Patent Application
20240417320
The present disclosure relates generally to foldable substrates and methods of making and, more particularly, to foldable substrates comprising a first central surface area recessed from a first major surface and methods of making foldable substrates.
Glass-based substrates are commonly used, for example, in display devices, for example, liquid crystal displays (LCDs), electrophoretic displays (EPD), organic light-emitting diode displays (OLEDs), plasma display panels (PDPs), or the like.
There is a desire to develop foldable versions of displays as well as foldable protective covers to mount on foldable displays. Foldable displays and covers should have good impact and puncture resistance. At the same time, foldable displays and covers should have small minimum bend radii (e.g., about 10 millimeters (mm) or less). However, plastic displays and covers with small minimum bend radii tend to have poor impact and/or puncture resistance. Furthermore, conventional wisdom suggests that ultra-thin glass-based sheets (e.g., about 75 micrometers (μm or microns) or less thick) with small minimum bend radii tend to have poor impact and/or puncture resistance. Furthermore, thicker glass-based sheets (e.g., greater than 125 micrometers) with good impact and/or puncture resistance tend to have relatively large minimum bend radii (e.g., about 30 millimeters or more). Consequently, there is a need to develop foldable apparatus that have low minimum bend radii and good impact and puncture resistance.
There are set forth herein foldable substrates, foldable apparatus comprising foldable substrates, and methods of making foldable substrates comprising foldable substrates that comprise a first portion and a second portion and foldable apparatus comprising foldable substrates. The portions can comprise glass-based and/or ceramic-based portions, which can provide good dimensional stability, reduced incidence of mechanical instabilities, good impact resistance, and/or good puncture resistance. The first portion and/or the second portion can comprise glass-based and/or ceramic-based portions comprising one or more compressive stress regions, which can further provide increased impact resistance and/or increased puncture resistance. By providing a substrate comprising a glass-based and/or ceramic-based substrate, the substrate can also provide increased impact resistance and/or puncture resistance while simultaneously facilitating good folding performance. In aspects, the substrate thickness can be sufficiently large (e.g., from about 80 micrometers (microns or μm) to about 2 millimeters (mm)) to further enhance impact resistance and puncture resistance. Providing foldable substrates comprising a central portion comprising a central thickness that is less than a substrate thickness can enable a small parallel plate distance (e.g., about 10 millimeters or less) based on the reduced thickness in the central portion.
In aspects, the foldable apparatus and/or foldable substrates can comprise a recess, for example, a first central surface area recessed from a first major surface by a first distance. Providing a recess can increase bendability of the foldable apparatus since the central thickness can be less than the substrate thickness. Additionally, controlling properties of a material positioned in the recess can control the position of a neutral axis of the foldable apparatus and/or foldable substrates, which can reduce (e.g., mitigate, eliminate) the incidence of mechanical instabilities, apparatus fatigue, and/or apparatus failure.
Providing a blunted edge between the first major surface and the second major surface and/or between the first central surface area and the second major surface can increase an impact resistance and/or decrease an incidence of failure of the foldable substrate. Providing the blunted edge extending around an entire periphery of the foldable substrate can further increase an impact resistance and/or decrease an incidence of failure of the foldable substrate. Further, providing the blunted edge comprising the first blunted surface area, the second blunted surface area, and the central blunted surface area can reduce and/or avoid mechanical instabilities. For example, the foldable substrate can be symmetric about a first plane extending in a direction of the central thickness and along a midline between the first portion and the second portion, and/or the foldable substrate can be symmetric about a second plane extending in the direction of the central thickness and perpendicular to the first plane. Providing a central region of the central portion that can be symmetric about a third plane extending parallel to the first central surface area and the second central surface area at a midpoint therebetween. Since mechanical instabilities can develop from an asymmetry in a region of the foldable substrate as a region where stress and/or strain concentrates, providing the central region symmetric about the first plane, the second plane, and/or the third plane can reduce the incidence of mechanical instabilities. Since the regions comprising the smallest thickness are the most susceptible to mechanical instabilities (e.g., lower critical buckling strain, less stress required to reach a critical buckling strain), reducing the chance of mechanical instabilities in the central region comprising the central thickness reduces the incidence of mechanical instabilities for the foldable substrate overall.
Providing the foldable substrate with a central portion that can be substantially unstrengthened can reduce an incidence of mechanical instabilities. For example, the unstrengthened central portion can result in a chemical strengthening induced expansion strain profile of the foldable substrate measured from a midline of the central portion that monotonically increase, which can reduce an incidence of mechanical instabilities. Similarly, a profile of absolute values of the maximum tensile stress or the maximum compressive stress of the foldable substrate measured from a midline of the central portion can monotonically increase. Alternatively, providing a central portion comprising a depth of compression and/or depth of layer as a percentage of the central thickness that is less than or equal to the corresponding depth of the first portion as a percentage of the substrate thickness can reduce an incidence of mechanical instabilities while increasing the puncture resistance of the entire foldable substrate.
Method aspects of the disclosure can reduce an incidence of mechanical instabilities while increasing an impact resistance and/or increase a puncture resistance of the foldable apparatus. For example, methods can produce the blunted edge described above that includes the central blunted surface area. Using the method of aspects of the disclosure comprising etching the foldable substrate after removing an initial edge can produce an edge surface with minimal surface flaws (e.g., preexisting or generated during prior processing) since surface flaws can be treated (e.g., blunted, removed, reduced) during the etching. By forming the edge surface before chemically strengthening the foldable substrate, mechanical instabilities of the foldable substrate can be avoided during processing as well as in the final foldable substrate. Providing the first barrier layer and the second barrier layer over the central portion can reduce mechanical instabilities by establishing the chemical strengthening induced expansion strain profile, maximum tensile stress profile, and/or compressive stress profile described above, which can reduce an incidence of mechanical instabilities. Providing a barrier layer comprising a covalent solid can minimize an amount of material needed to achieve one of the above-mentioned profiles. Providing a barrier layer comprising aluminum nitride, aluminum oxynitride, and/or sputtered silicon nitride can achieve one of the above-mentioned profiles while being removable without damaging the foldable substrate.
Some example aspects of the disclosure are described below with the understanding that any of the features of the various aspects may be used alone or in combination with one another.
Aspect 1. A foldable substrate comprising:
Aspect 2. The foldable substrate of aspect 1, wherein a first thickness of the first blunted surface area in a direction of the substrate thickness is in a range from about 1 micrometer to about 50 micrometers, and a second thickness of the second blunted surface area in the direction of the substrate thickness is in a range from about 1 micrometer to about 50 micrometers.
Aspect 3. The foldable substrate of aspect 1, wherein a first thickness of the first blunted surface area in a direction of the substrate thickness is in a range from about 5 micrometers to about 25 micrometers, and a second thickness of the second blunted surface area in the direction of the substrate thickness is in a range from about 5 micrometers to about 25 micrometers.
Aspect 4. The foldable substrate of any one of aspects 1-3, wherein the first blunted surface area comprises a chamfered surface.
Aspect 5. The foldable substrate of any one of aspects 1-4, wherein the second blunted surface area comprises a chamfered surface.
Aspect 6. The foldable substrate of any one of aspects 1-5, wherein the first distance is about 20% to about 80% of the substrate thickness.
Aspect 7. The foldable substrate of aspect 6, wherein the first distance is about 50% to about 75% of the substrate thickness.
Aspect 8. The foldable substrate of any one of aspects 1-7, wherein the first portion comprises a first compressive stress region extending from the first major surface to a first depth of compression from the first major surface and a second compressive stress region extending from the second major surface to a second depth of compression from the second major surface, the second portion comprises a third compressive stress region extending from the first major surface to a third depth of compression from the first major surface and a fourth compressive stress region extending from the second major surface to a fourth depth of compression from the second major surface.
Aspect 9. The foldable substrate of aspect 8, further comprising a first depth of layer of one or more alkali metal ions associated with the first depth of compression, a second depth of layer of one or more alkali metal ions associated with the second depth of compression, a third depth of layer of one or more alkali metal ions associated with the third depth of compression, and a fourth depth of layer of one or more alkali metal ions associated with the fourth depth of compression.
Aspect 10. The foldable substrate of aspect 9, wherein the first depth of layer as a percentage of the substrate thickness is in a range from about 10% to about 30%, the second depth of layer as a percentage of the substrate thickness is in a range from about 10% to about 30%, the third depth of layer as a percentage of the substrate thickness is in a range from about 10% to about 30%, and the fourth depth of layer as a percentage of the substrate thickness is in a range from about 10% to about 30%.
Aspect 11. The foldable substrate of aspect 10, wherein the first depth of layer is substantially equal to the second depth of layer.
Aspect 12. The foldable substrate of any one of aspects 10-11, wherein the first depth of layer is substantially equal to the third depth of layer.
Aspect 13. The foldable substrate of any one of aspects 8-12, wherein the first depth of compression as a percentage of the substrate thickness is in a range from about 10% to about 30%, the second depth of compression as a percentage of the substrate thickness is in a range from about 10% to about 30%, the third depth of compression as a percentage of the substrate thickness is in a range from about 10% to about 30%, and the fourth depth of compression as a percentage of the substrate thickness is in a range from about 10% to about 30%.
Aspect 14. The foldable substrate of any one of aspects 9-13, wherein the first compressive stress region comprises a first maximum compressive stress of about 500 MegaPascals or more, the second compressive stress region comprises a second maximum compressive stress, the third compressive stress region comprises a third maximum compressive stress of about 500 MegaPascals or more, and the fourth compressive stress region comprises a fourth maximum compressive stress.
Aspect 15. The foldable substrate of aspect 14, wherein the second maximum compressive stress is about 500 MegaPascals or more, and the fourth maximum compressive stress is about 500 MegaPascals or more.
Aspect 16. The foldable substrate of any one of aspects 1-15, further comprising a first central compressive stress region extending to a first central depth of compression from the first central surface area, and a second central compressive stress region extending to a second central depth of compression extending from the second central surface area.
Aspect 17. The foldable substrate of aspect 16, wherein the first central depth of compression as a percentage of the central thickness is about 10% or less, and the second central depth of compression as a percentage of the central thickness is about 10% or less.
Aspect 18. The foldable substrate of any one of aspects 1-15, wherein the central portion is substantially unstrengthened.
Aspect 19. The foldable substrate of any one of aspects 1-18, wherein the foldable substrate is substantially symmetric about a first plane extending in the direction of the central thickness and along a midline between the first portion and the second portion.
Aspect 20. The foldable substrate of aspect 19, wherein the foldable substrate is substantially symmetric about a second plane extending in the direction of the central thickness and perpendicular to the first plane.
Aspect 21. The foldable substrate of any one of aspects 1-19, wherein a central region corresponding to the first central surface area is substantially symmetric about a third plane extending parallel to the first central surface area and positioned at a midpoint between the first central surface area and the second central surface area in a direction of central thickness.
Aspect 22. The foldable substrate of any one of aspects 1-21, wherein the substrate thickness is in a range from about 125 micrometers to about 200 micrometers.
Aspect 23. The foldable substrate of any one of aspects 1-22, wherein the central thickness is in a range from about 25 micrometers to about 80 micrometers.
Aspect 24. The foldable substrate of any one of aspects 1-23, wherein the foldable substrate comprises a glass-based substrate.
Aspect 25. The foldable substrate of any one of aspects 1-24, wherein the foldable substrate comprises a ceramic-based substrate.
Aspect 26. The foldable substrate of any one of aspects 1-25, wherein the foldable substrate achieves a parallel plate distance of 10 millimeters.
Aspect 27. The foldable substrate of any one of aspects 1-26, wherein the foldable substrate comprises a minimum parallel plate distance in a range from about 2 millimeters to about 10 millimeters.
Aspect 28. A foldable apparatus comprising:
Aspect 29. The foldable apparatus of aspect 28, further comprising a polymer-based portion at least partially positioned in a recess defined between a first central plane defined by the first major surface and a second central plane defined by the first central surface area, the polymer-based portion comprising a third contact surface and a fourth contact surface opposite the third contact surface, the third contact surface facing the first central surface area, and the fourth contact surface area facing the first contact surface.
Aspect 30. The foldable apparatus of aspect 28, wherein at least a portion of the adhesive is positioned in a recess defined between a first central plane defined by the first major surface and a second central plane defined by the first central surface area.
Aspect 31. The foldable apparatus of any one of aspects 28-30, further comprising a display device attached to the second contact surface of the adhesive.
Aspect 32. The foldable apparatus of any one of aspects 28-31, further comprising a polymer layer disposed over the second major surface of the foldable substrate.
Aspect 33. A method of making a foldable substrate comprising a substrate thickness defined between a first major surface and a second major surface opposite the first major surface, a central thickness less than the substrate thickness defined between a first central surface area and a second central surface area opposite the first central surface area, the first central surface area recessed from the first major surface by a first distance, and a central portion comprising the central thickness positioned between a first portion and a second portion, the method comprising:
Aspect 34. A method of making a foldable substrate comprising a substrate thickness defined between a first major surface and a second major surface opposite the first major surface, the method comprising:
Aspect 35. The method of aspect 34, further comprising, before the contacting the central portion of the foldable substrate with the first etchant, disposing a third etch mask over the entire second major surface of the foldable substrate.
Aspect 36. The method of any one of aspects 34-35, wherein the first etchant comprises an acid.
Aspect 37. The method of aspect 36, wherein the first etchant comprises hydrofluoric acid.
Aspect 38. The method of any one of aspects 33-37, wherein the first barrier layer comprises one of aluminum nitride, aluminum oxynitride, sputtered silicon nitride, or combinations thereof.
Aspect 39. The method of any one of aspects 33-38, wherein the second barrier layer comprises the same material as the first barrier layer.
Aspect 40. The method of any one of aspects 33-39, wherein the disposing the first barrier layer comprises sputtering, chemical vapor deposition, thermal evaporation, or electron-beam deposition.
Aspect 41. The method of aspect 40, wherein the disposing the first barrier layer comprises sputtering.
Aspect 42. The method of any one of aspects 33-41, wherein a first barrier thickness of the first barrier layer is in a range from about 10 nanometers to about 2 micrometers.
Aspect 43. The method of any one of aspects 33-42, further comprising, before chemically strengthening the first portion and the second portion:
Aspect 44. The method of aspect 43, wherein removing the another portion of the first barrier layer comprises contacting the another portion of the first barrier layer with an alkaline solution.
Aspect 45. The method of any one of aspects 43-44, further comprising, before chemically strengthening the first portion and the second portion:
Aspect 46. The method of aspect 45, wherein removing the another portion of the second barrier layer comprises contacting the another portion of the second barrier layer with an alkaline solution.
Aspect 47. The method of any one of aspects 33-43, wherein removing the first barrier layer comprises contacting the first barrier layer with an alkaline solution.
Aspect 48. The method of any one of aspects 33-43, wherein removing the second barrier layer comprises contacting the second barrier layer with an alkaline solution.
Aspect 49. The method of any one of aspects 44 and 46-48 inclusive, wherein the alkaline solution comprises a temperature in a range from about 40° C. to about 90° C.
Aspect 50. The method of any one of aspects 33-49, wherein the second etchant comprises an acid.
Aspect 51. The method of aspect 50, wherein the second etchant comprises hydrofluoric acid.
Aspect 52. The method of any one of aspects 33-51, wherein the first etchant comprises the same composition as the second etchant.
Aspect 53. The method of any one of aspects 33-52, wherein a first thickness of the first blunted surface area in a direction of the substrate thickness is in a range from about 1 micrometer to about 50 micrometers, and a second thickness of the second blunted surface area in the direction of the substrate thickness is in a range from about 1 micrometer to about 50 micrometers.
Aspect 54. The method of any one of aspects 33-52, wherein a first thickness of the first blunted surface area in a direction of the substrate thickness is in a range from about 5 micrometers to about 25 micrometers, and a second thickness of the second blunted surface area in the direction of the substrate thickness is in a range from about 5 micrometers to about 25 micrometers.
Aspect 55. The method of any one of aspects 33-54, wherein contacting the intermediate edge with a second etchant comprises removing from about 1 micrometer to about 50 micrometers of material from the intermediate edge.
Aspect 56. The method of any one of aspects 33-55, wherein the first blunted surface area comprises a chamfered surface.
Aspect 57. The method of any one of aspects 33-56, wherein the second blunted surface area comprises a chamfered surface.
Aspect 58. The method of any one of aspects 33-57, wherein, before the chemically strengthening, the foldable substrate is substantially unstrengthened.
Aspect 59. The method of any one of aspects 33-58, further comprising, after removing the first etch mask and removing the second edge mask, further chemically strengthening the foldable substrate.
Aspect 60. The method of any one of aspects 33-59, wherein the first distance is about 20% to about 80% of the substrate thickness.
Aspect 61. The method of aspect 60, wherein the first distance is about 50% to about 75% of the substrate thickness.
Aspect 62. The method of any one of aspects 33-61, wherein the substrate thickness is in a range from about 125 micrometers to about 200 micrometers.
Aspect 63. The method of any one of aspects 33-62, wherein the foldable substrate comprises a glass-based substrate.
Aspect 64. The method of any one of aspects 33-63, wherein the foldable substrate comprises a ceramic-based substrate.
Aspect 65. The method of any one of aspects 33-64, wherein the foldable substrate achieves a parallel plate distance of 10 millimeters.
Aspect 66. The method of any one of aspects 33-65, wherein the foldable substrate comprises a minimum parallel plate distance in a range from about 2 millimeters to about 10 millimeters.
Aspect 67. The method of any one of aspects 33-66, wherein the foldable substrate is substantially symmetric about a first plane extending in the direction of the central thickness and along a midline between the first portion and the second portion.
Aspect 68. The method of aspect 67, wherein the foldable substrate is substantially symmetric about a second plane extending in the direction of the central thickness and perpendicular to the first plane.
Aspect 69. The method of any one of aspects 33-67, wherein a central region corresponding to the first central surface area is substantially symmetric about a third plane extending parallel to the first central surface area and positioned at a midpoint between the first central surface area and the second central surface area in a direction of the central thickness.
The above and other features and advantages of aspects of the present disclosure are better understood when the following detailed description is read with reference to the accompanying drawings, in which:
Throughout the disclosure, the drawings are used to emphasize certain aspects. As such, it should not be assumed that the relative size of different regions, portions, and substrates shown in the drawings are proportional to its actual relative size, unless explicitly indicated otherwise.
Aspects will now be described more fully hereinafter with reference to the accompanying drawings in which example aspects are shown. Whenever possible, the same reference numerals are used throughout the drawings to refer to the same or like parts.
The foldable apparatus 101, 301, and 401 comprise a first portion 221, a second portion 231, and a central portion 281 positioned between the first portion 221 and the second portion 231. In aspects, as shown in
Throughout the disclosure, with reference to
The foldable substrate 201 can comprise a glass-based substrate and/or a ceramic-based substrate having a pencil hardness of 8H or more, for example, 9H or more. As used herein, pencil hardness is measured using ASTM D 3363-20 with standard lead graded pencils. Providing a glass-based foldable substrate and/or a ceramic-based foldable substrate can enhance puncture resistance and/or impact resistance.
In aspects, the foldable substrate 201 can comprise a glass-based substrate. As used herein, “glass-based” includes both glasses and glass-ceramics, wherein glass-ceramics have one or more crystalline phases and an amorphous, residual glass phase. A glass-based material (e.g., glass-based substrate) may comprise an amorphous material (e.g., glass) and optionally one or more crystalline materials (e.g., ceramic). Amorphous materials and glass-based materials may be strengthened. As used herein, the term “strengthened” may refer to a material that has been chemically strengthened, for example, through ion exchange of larger ions for smaller ions in the surface of the substrate, as discussed below. However, other strengthening methods, for example, thermal tempering, or utilizing a mismatch of the coefficient of thermal expansion between portions of the substrate to create compressive stress and central tension regions, may be utilized to form strengthened substrates. Exemplary glass-based materials, which may be free of lithia or not, comprise soda lime glass, alkali aluminosilicate glass, alkali-containing borosilicate glass, alkali-containing aluminoborosilicate glass, alkali-containing phosphosilicate glass, and alkali-containing aluminophosphosilicate glass. In aspects, glass-based material can comprise an alkali-containing glass or an alkali-free glass, either of which may be free of lithia or not. In aspects, the glass material can be alkali-free and/or comprise a low content of alkali metals (e.g., R2O of about 10 mol % or less, wherein R2O comprises Li2O Na2O, K2O, or the more expansive list provided below). In one or more aspects, a glass-based material may comprise, in mole percent (mol %): SiO2 in a range from about 40 mol % to about 80%, Al2O3 in a range from about 5 mol % to about 30 mol %, B2O3 in a range from 0 mol % to about 10 mol %, ZrO2 in a range from 0 mol % to about 5 mol %, P2O5 in a range from 0 mol % to about 15 mol %, TiO2 in a range from 0 mol % to about 2 mol %, R2O in a range from 0 mol % to about 20 mol %, and RO in a range from 0 mol % to about 15 mol %. As used herein, R2O can refer to an alkali-metal oxide, for example, Li2O, Na2O, K2O, Rb2O, and Cs2O. As used herein, RO can refer to MgO, CaO, SrO, BaO, and ZnO. In aspects, a glass-based substrate may optionally further comprise in a range from 0 mol % to about 2 mol % of each of Na2SO4, NaCl, NaF, NaBr, K2SO4, KCl, KF, KBr, As2O3, Sb2O3, SnO2, Fe2O3, MnO, MnO2, MnO3, Mn2O3, Mn3O4, Mn2O7. “Glass-ceramics” include materials produced through controlled crystallization of glass. In aspects, glass-ceramics have about 1% to about 99% crystallinity. Examples of suitable glass-ceramics may include Li2O—Al2O3—SiO2 system (i.e., LAS-System) glass-ceramics, MgO—Al2O3—SiO2 system (i.e., MAS-System) glass-ceramics, ZnO×Al2O3×nSiO2 (i.e., ZAS system), and/or glass-ceramics that include a predominant crystal phase including β-quartz solid solution, β-spodumene, cordierite, petalite, and/or lithium disilicate. The glass-ceramic substrates may be strengthened using the chemical strengthening processes. In one or more aspects, MAS-System glass-ceramic substrates may be strengthened in Li2SO4 molten salt, whereby an exchange of 2Li+ for Mg2+ can occur.
In aspects, the foldable substrate 201 can comprise a ceramic-based substrate. As used herein, “ceramic-based” includes both ceramics and glass-ceramics, wherein glass-ceramics have one or more crystalline phases and an amorphous, residual glass phase. Ceramic-based materials may be strengthened (e.g., chemically strengthened). In aspects, a ceramic-based material can be formed by heating a glass-based material to form ceramic (e.g., crystalline) portions. In further aspects, ceramic-based materials may comprise one or more nucleating agents that can facilitate the formation of crystalline phase(s). In aspects, ceramic-based materials can comprise one or more oxides, nitrides, oxynitrides, carbides, borides, and/or silicides. Example aspects of ceramic oxides include zirconia (ZrO2), zircon (ZrSiO4), an alkali-metal oxide (e.g., sodium oxide (Na2O)), an alkali earth metal oxide (e.g., magnesium oxide (MgO)), titania (TiO2), hafnium oxide (Hf2O), yttrium oxide (Y2O3), iron oxides, beryllium oxides, vanadium oxide (VO2), fused quartz, mullite (a mineral comprising a combination of aluminum oxide and silicon dioxide), and spinel (MgAl2O4). Example aspects of ceramic nitrides include silicon nitride (Si3N4), aluminum nitride (AlN), gallium nitride (GaN), beryllium nitride (Be3N2), boron nitride (BN), tungsten nitride (WN), vanadium nitride, alkali earth metal nitrides (e.g., magnesium nitride (Mg3N2)), nickel nitride, and tantalum nitride. Example aspects of oxynitride ceramics include silicon oxynitride, aluminum oxynitride, and a SiAlON (a combination of alumina and silicon nitride and can have a chemical formula, for example, Si12−m−nAlm+nOnN16−n, Si6−nAlnOnN8−n, or Si2−nAlnO1+nN2−n, where m, n, and the resulting subscripts are all non-negative integers). Example aspects of carbides and carbon-containing ceramics include silicon carbide (SiC), tungsten carbide (WC), an iron carbide, boron carbide (B4C), alkali-metal carbides (e.g., lithium carbide (Li4C3)), alkali earth metal carbides (e.g., magnesium carbide (Mg2C3)), and graphite. Example aspects of borides include chromium boride (CrB2), molybdenum boride (Mo2B5), tungsten boride (W2B5), iron boride, titanium boride, zirconium boride (ZrB2), hafnium boride (HfB2), vanadium boride (VB2), Niobium boride (NbB2), and lanthanum boride (LaB6). Example aspects of silicides include molybdenum disilicide (MoSi2), tungsten disilicide (WSi2), titanium disilicide (TiSi2), nickel silicide (NiSi), alkali earth silicide (e.g., sodium silicide (NaSi)), alkali-metal silicide (e.g., magnesium silicide (Mg2Si)), hafnium disilicide (HfSi2), and platinum silicide (PtSi).
Throughout the disclosure, a tensile strength, ultimate elongation (e.g., strain at failure), and yield point of a polymeric material (e.g., adhesive, polymer-based portion) is determined using ASTM D638 using a tensile testing machine, for example, an Instron 3400 or Instron 6800, at 23° C. and 50% relative humidity with a type I dogbone shaped sample. Throughout the disclosure, an elastic modulus (e.g., Young's modulus) and/or a Poisson's ratio is measured using ISO 527-1:2019. In aspects, the foldable substrate 201 can comprise an elastic modulus of about 1 GigaPascal (GPa) or more, about 3 GPa or more, about 5 GPa or more, about 10 GPa or more, about 100 GPa or less, about 80 GPa or less, about 60 GPa or less, or about 20 GPa or less. In aspects, the foldable substrate 201 can comprise an elastic modulus in a range from about 1 GPa to about 100 GPa, from about 1 GPa to about 80 GPa, from about 3 GPa to about 80 GPa, from about 3 GPa to about 60 GPa, from about 5 GPa to about 60 GPa, from about 5 GPa to about 20 GPa, from about 10 GPa to about 20 GPa, or any range or subrange therebetween. In further aspects, the foldable substrate 201 can comprise a glass-based material or a ceramic-based material comprising an elastic modulus in a range from about 10 GPa to about 100 GPa, from about 40 GPa to about 100 GPa, from about 60 GPa to about 100 GPa, from about 60 GPa to about 80 GPa, from about 80 GPa to about 100 GPa, or any range or subrange therebetween.
In aspects, the foldable substrate 201 can be optically transparent. As used herein, “optically transparent” or “optically clear” means an average transmittance of 70% or more in the wavelength range of 400 nm to 700 nm through a 1.0 mm thick piece of a material. In aspects, an “optically transparent material” or an “optically clear material” may have an average transmittance of 75% or more, 80% or more, 85% or more, or 90% or more, 92% or more, 94% or more, 96% or more in the wavelength range of 400 nm to 700 nm through a 1.0 mm thick piece of the material. The average transmittance in the wavelength range of 400 nm to 700 nm is calculated by measuring the transmittance of whole number wavelengths from about 400 nm to about 700 nm and averaging the measurements.
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In aspects, the third plane 204c can be substantially parallel to the first plane 204a and/or the second plane 204b. In further aspects, as shown in
A central thickness 217 can be defined between the first central surface area 211 and the second central surface area 213, which can be measured as the distance between the third plane 204c and the second plane 204b. In aspects, the central thickness 217 can be about 1 μm or more, about 5 μm or more, about 10 μm or more, about 25 μm or more, about 40 μm or more, about 200 μm or less, about 150 μm or less, about 100 μm or less, about 80 μm or less, about 60 μm or less, or about 50 μm or less. In aspects, the central thickness 217 can be in a range from about 1 μm to about 200 μm, from about 1 μm to about 150 μm from about 1 μm to about 100 μm, from about 5 μm to about 100 μm, from about 10 μm to about 100 μm, from about 10 μm to about 80 μm, from about 25 μm to about 80 μm, from about 25 μm to about 60 μm, from about 40 μm to about 60 μm, or any range or subrange therebetween. In aspects, the central thickness 217 can be in a range from about 5 μm to about 200 μm, from about 10 μm to about 200 μm, from about 25 μm to about 200 μm, from about 25 μm to about 150 μm, from about 40 μm to about 150 μm, from about 40 μm to about 100 μm, from about 40 μm to about 80 μm, or any range or subrange therebetween. In aspects, the central thickness 217 as a percentage of the substrate thickness 207 can be about 0.5% or more, about 1% or more, about 2% or more, about 5% or more, about 6% or more, about 20% or less, about 13% or less, about 10% or less, or about 8% or less. In aspects, the central thickness 217 as a percentage of the substrate thickness 207 can be in a range from about 0.5% to about 20%, from about 0.5% to about 13%, from about 1% to about 13%, from about 1% to about 10%, from about 2% to about 10%, from about 2% to about 8%, from about 5% to about 8%, from about 6% to about 8%, or any range or subrange therebetween. In aspects, the central region 248 of the central portion 281 can correspond to a region comprising the central thickness 217. By providing the first central surface area 211 of the central portion 281 extending along the third plane 204c parallel to the second central surface area 213 of the central portion 281 extending along the second plane 204b, a uniform central thickness 217 may extend across the central portion 281 that can provide enhanced folding performance at a predetermined thickness for the central thickness 217. A uniform central thickness 217 across the central portion 281 can improve folding performance by preventing stress concentrations that would occur if a portion of the central portion 281 was thinner than the rest of the central portion 281.
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Throughout the disclosure, an edge is considered to be “blunted” if a first surface area of the edge forms an obtuse internal angle with the first major surface, a second surface area of the edge forms an obtuse internal angle with the second major surface, and/or a central surface area of the edge forms an obtuse internal angle with the first central surface area. An angle is measured using two points of each surface, where each set of points is spaced along the corresponding surface by at least 1 μm. For example, as shown in
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Foldable substrates (e.g., foldable substrate 201) can be subject to a variety of types of mechanical instabilities. Throughout the disclosure, mechanical instabilities include localized mechanical instabilities as well as systemic mechanical instabilities. As used herein, a localized mechanical instability manifests as a deviation (e.g., a plurality of deviations) from a plane of a surface (e.g., first central surface area) without distorting the surface as a whole, for example, buckling and/or wrinkling. As used herein, a systemic mechanical instability manifests as a distortion of an entire surface from a plane, for example, warpage. An onset of mechanical instability (e.g., localized mechanical instability) may occur when a critical strain (e.g., critical buckling strain) of a portion (e.g., central portion) of the foldable substrate is exceeded. For example, a critical buckling strain of a central portion resembling the foldable substrate 201 of
Chemical strengthening induced expansion strain of the central portion of the foldable substrate resulting from chemically strengthening the foldable substrate is proportional to a product of the network dilation coefficient (B), a concentration difference (C), and a difference between a depth of layer of the central portion divided by the central thickness and a depth of layer of the first portion (or second portion) divided by the substrate thickness. As used herein, a network dilation coefficient refers to how much a volume of a foldable substrate (e.g., first portion, second portion, central portion) expands as a result of an increase in the concentration of one or more alkali ions exchanged into the substrate (e.g., as a result of chemical strengthening). In aspects, a network dilation constant of the first portion and/or a network dilation constant of the second portion can be substantially equal to a network dilation constant of the central portion, for example, if the first portion and/or the second portion and the central portion all comprise the same material prior to the chemically strengthening. Without wishing to be bound by theory, it has been observed that mechanical instabilities in the central portion occur when the chemical strengthening induced expansion strain of the central portion is not greater than that in the first transition region and/or the second transition region.
One way to reduce and/or avoid mechanical instabilities is to produce a chemical strengthening induced expansion strain profiles where the strain monotonically increases as thickness increases (i.e., away from a midline of the central portion between the first portion and the second portion). For example, by providing a substantially unstrengthened central portion (e.g., first transition region, central region, second transition region), the chemical strengthening induced expansion strain can be 0 in the central portion with positive chemically strengthened induced expansion strain in the first portion and the second portion. In aspects, the maximum tensile stress of the central region can be less than or equal to the maximum tensile stress of the first transition region and/or the second transition region. In aspects, a depth of layer of the central region as a percentage of the central thickness can be less than or equal to a depth of layer of the first transition region and/or the second transition region as a percentage of a local thickness where the measurement was taken. In aspects, a depth of compression of the central region as a percentage of the central thickness can be less than or equal to a depth of compression of the first transition region and/or the second transition region as a percentage of a local thickness where the measurement was taken.
Another way to reduce and/or avoid mechanical instabilities is to provide a central portion (e.g., central region) that is symmetric along one or more planes. Without wishing to be bound by theory, mechanical instabilities can develop from an asymmetry in a region of the foldable substrate, where the strain concentrates. In aspects, as discussed above with reference to
As used herein, if a first layer and/or component is described as “disposed over” a second layer and/or component, other layers may or may not be present between the first layer and/or component and the second layer and/or component. Furthermore, as used herein, “disposed over” does not refer to a relative position with reference to gravity. For example, a first layer and/or component can be considered “disposed over” a second layer and/or component, for example, when the first layer and/or component is positioned underneath, above, or to one side of a second layer and/or component. As used herein, a first layer and/or component described as “bonded to” a second layer and/or component means that the layers and/or components are bonded to each other, either by direct contact and/or bonding between the two layers and/or components or via an adhesive layer. As used herein, a first layer and/or component described as “contacting” or “in contact with” a second layer and/or components refers to direct contact and includes the situations where the layers and/or components are bonded to each other.
As shown in
In aspects, as shown in
In aspects, the adhesive layer 261 can comprise one or more of a polyolefin, a polyamide, a halide-containing polymer (e.g., polyvinylchloride or a fluorine-containing polymer), an elastomer, a urethane, phenolic resin, parylene, polyethylene terephthalate (PET), and polyether ether ketone (PEEK). Example aspects of polyolefins include low molecular weight polyethylene (LDPE), high molecular weight polyethylene (HDPE), ultrahigh molecular weight polyethylene (UIMWPE), and polypropylene (PP). Example aspects of fluorine-containing polymers include polytetrafluoroethylene (PTFE), polyvinylfluoride (PVF), polyvinylidene fluoride (PVDF), perfluoropolyether (PFPE), perfluorosulfonic acid (PFSA), a perfluoroalkoxy (PFA), fluorinated ethylene propylene (FEP) polymers, and ethylene tetrafluoro ethylene (ETFE) polymers. Example aspects of elastomers include rubbers (e.g., polybutadiene, polyisoprene, chloroprene rubber, butyl rubber, nitrile rubber) and block copolymers (e.g., styrene-butadiene, high-impact polystyrene, poly(dichlorophosphazene). In further aspects, the adhesive layer 261 can comprise an optically clear adhesive. In even further aspects, the optically clear adhesive can comprise one or more optically transparent polymers: an acrylic (e.g., polymethylmethacrylate (PMMA)), an epoxy, silicone, and/or a polyurethane. Examples of epoxies include bisphenol-based epoxy resins, novolac-based epoxies, cycloaliphatic-based epoxies, and glycidylamine-based epoxies. In even further aspects, the optically clear adhesive can comprise, but is not limited to, acrylic adhesives, for example, 3M 8212 adhesive, or an optically transparent liquid adhesive, for example, a LOCTITE optically transparent liquid adhesive. Exemplary aspects of optically clear adhesives comprise transparent acrylics, epoxies, silicones, and polyurethanes. For example, the optically transparent liquid adhesive could comprise one or more of LOCTITE AD 8650, LOCTITE AA 3922, LOCTITE EA E-05MR, LOCTITE UK U-09LV, which are all available from Henkel.
In aspects, the adhesive layer 261 can comprise an elastic modulus of about 0.001 MegaPascals (MPa) or more, about 0.01 MPa or more, about 0.1 MPa or more, about 1 MPa or less, about 0.5 MPa or less, about 0.1 MPa or less, or about 0.05 MPa or less. In aspects, the adhesive layer 261 can comprise an elastic modulus in a range from about 0.001 MPa to about 1 MPa, from about 0.01 MPa to about 1 MPa, from about 0.01 MPa to about 0.5 MPa, from about 0.05 MPa to about 0.5 MPa, from about 0.1 MPa to about 0.5 MPa, from about 0.001 MPa to about 0.5 MPa, from about 0.001 MPa to about 0.01 MPa, or any range or subrange therebetween. In aspects, the adhesive layer can comprise an elastic modulus within one or more of the ranges discussed below for the elastic modulus of the polymer-based portion 241.
As shown in
In aspects, the polymer-based portion 241 comprises a polymer (e.g., optically transparent polymer). In further aspects, the polymer-based portion 241 can comprise one or more of an optically transparent: an acrylic (e.g., polymethylmethacrylate (PMMA)), an epoxy, a silicone, and/or a polyurethane. Examples of epoxies include bisphenol-based epoxy resins, novolac-based epoxies, cycloaliphatic-based epoxies, and glycidylamine-based epoxies. In further aspects, the polymer-based portion 241 comprise one or more of a polyolefin, a polyamide, a halide-containing polymer (e.g., polyvinylchloride or a fluorine-containing polymer), an elastomer, a urethane, phenolic resin, parylene, polyethylene terephthalate (PET), and polyether ether ketone (PEEK). Example aspects of polyolefins include low molecular weight polyethylene (LDPE), high molecular weight polyethylene (HDPE), ultrahigh molecular weight polyethylene (UHMWPE), and polypropylene (PP). Example aspects of fluorine-containing polymers include polytetrafluoroethylene (PTFE), polyvinylfluoride (PVF), polyvinylidene fluoride (PVDF), perfluoropolyether (PFPE), perfluorosulfonic acid (PFSA), a perfluoroalkoxy (PFA), fluorinated ethylene propylene (FEP) polymers, and ethylene tetrafluoro ethylene (ETFE) polymers. Example aspects of elastomers include rubbers (e.g., polybutadiene, polyisoprene, chloroprene rubber, butyl rubber, nitrile rubber) and block copolymers (e.g., styrene-butadiene, high-impact polystyrene, poly(dichlorophosphazene), for example, comprising one or more of polystyrene, polydichlorophosphazene, and poly(5-ethylidene-2-norbornene). In aspects, the polymer-based portion can comprise a sol-gel material. Example aspects of polyurethanes comprise thermoset polyurethanes, for example, Dispurez 102 available from Incorez and thermoplastic polyurethanes, for example, KrystalFlex PE505 available from Huntsman. In even further aspects, the second portion can comprise an ethylene acid copolymer. An exemplary aspect of an ethylene acid copolymer includes SURLYN available from Dow (e.g., Surlyn PC-2000, Surlyn 8940, Surlyn 8150). An additional exemplary aspect for the second portion comprises Eleglass w802-GL044 available from Axalta with from 1 wt % to 2 wt % cross-linker. In aspects, the polymer-based portion 241 can further comprise nanoparticles, for example, carbon black, carbon nanotubes, silica nanoparticles, or nanoparticles comprising a polymer. In aspects, the polymer-based portion can further comprise fibers to form a polymer-fiber composite.
In aspects, the polymer-based portion 241 can comprise an elastic modulus of about 0.001 MegaPascals (MPa) or more, about 0.001 MP or more, about 1 MPa or more, about 10 MPa or more, about 20 MPa or more, about 100 MPa or more, about 200 MPa or more, about 1,000 MPa or more, about 5,000 MPa or less, about 3,000 MPa or less, about 1,000 MPa or less, about 500 MPa or less, or about 200 MPa or less. In aspects, the polymer-based portion 241 can comprise an elastic modulus in a range from about 0.001 MPa to about 5,000 MPa, from about 0.01 MPa to about 3,000 MPa, from about 0.01 MPa to about 1,000 MPa, from about 0.01 MPa to about 500 MPa, from about 0.01 MPa to about 200 MPa, from about 1 MPa to about 200 MPa, from about 10 MPa to about 200 MPa, from about 100 MPa to about 200 MPa, or any range or subrange therebetween. In aspects, the polymer-based portion 241 can comprise an elastic modulus in a range from about 1 MPa to about 5,000 MPa, from about 10 MPa to about 5,000 MPa, from about 10 MPa to about 1,000 MPa, from about 20 MPa to about 1,000 MPa, from about 20 MPa to about 200 MPa, or any range or subrange therebetween. In aspects, the elastic modulus of the polymer-based portion 241 can be in a range from about 1 GPa to about 20 GPa, from about 1 GPa to about 18 GPa, from about 1 GPa to about 10 GPa, from about 1 GPa to about 5 GPa, from about 1 GPa to about 3 GPa, or any range or subrange therebetween. By providing a polymer-based portion 241 with an elastic modulus in a range from about 0.001 MPa to about 5,000 MPa (e.g., in a range from about 10 MPa to about 3 GPa), folding of the foldable apparatus without failure can be facilitated. In aspects, the adhesive layer 261 comprises an elastic modulus greater than the elastic modulus of the polymer-based portion 241, which arrangement provides improved performance in puncture resistance. In aspects, the elastic modulus of the polymer-based portion 241 can be less than the elastic modulus of the foldable substrate 201. In aspects, the adhesive layer 261 may comprise an elastic modulus within the ranges listed above in this paragraph. In further aspects, the adhesive layer 261 may comprise substantially the same elastic modulus as the elastic modulus of the polymer-based portion 241. In further aspects, the elastic modulus of the adhesive layer 261 can be in a range from about 1 GPa to about 20 GPa, from about 1 GPa to about 18 GPa, from about 1 GPa to about 10 GPa, from about 1 GPa to about 5 GPa, from about 1 GPa to about 3 GPa, or any range or subrange therebetween. In aspects, the elastic modulus of the polymer-based portion 241 can be less than the elastic modulus of the foldable substrate 201.
In aspects, although not shown, a coating can be disposed over the second major surface 205 of the foldable substrate 201. In further aspects, the coating can be disposed over the first portion 221, the second portion 231, and the central portion 281. In aspects, the coating can contact the foldable substrate 201. In aspects, although not shown, a coating can be disposed over the first major surface 203 of the foldable substrate 201 with one or more of an adhesive layer, polymer-based portion, release liner, or display device facing the second major surface 205 instead of the first major surface 203. In further aspects, at least a part of the coating can be positioned in the recess 219. In even further aspects, the coating can fill the recess 219. In aspects, the coating can comprise a coating thickness defined as a minimum distance in the direction 202 of the substrate thickness 207. In further aspects, the coating thickness can be about 0.1 μm or more, about 1 μm or more, about 5 μm or more, about 10 μm or more, about 15 μm or more, about 20 μm or more, about 25 μm or more, about 40 μm or more, about 50 μm or more, about 60 μm or more, about 70 μm or more, about 80 μm or more, about 90 μm or more, about 200 μm or less, about 100 μm or less, or about 50 μm or less, about 30 μm or less, about 25 μm or less, about 20 μm or less, about 20 μm or less, about 15 μm or less, or about 10 μm or less. In aspects, the coating thickness can be in a range from about 0.1 μm to about 200 μm, from about 1 μm to about 200 μm, from about 10 μm to about 200 μm, from about 50 μm to about 200 μm, from about 0.1 μm to about 100 μm, from about 1 μm to about 100 μm, from about 10 μm to about 100 μm, from about 20 μm to about 100 μm, from about 30 μm to about 100 μm, from about 40 μm to about 100 μm, from about 50 μm to about 100 μm, from about 60 μm to about 100 μm, from about 70 μm to about 100 μm, from about 80 μm to about 100 μm, from about 90 μm to about 100 μm, from about 0.1 μm to about 50 μm, from about 1 μm to about 50 μm, from about 10 μm to about 50 μm, or any range or subrange therebetween. In further aspects, the coating thickness can be in a range from about 0.1 μm to about 50 μm, from about 0.1 μm to about 30 μm, from about 0.1 μm to about 25 μm, from about 0.1 μm to about 20 μm, from about 0.1 μm to about 15 μm, from about 0.1 μm to about 10 μm, from about 1 μm to about 30 μm, from about 1 μm to about 25 μm, from about 1 μm to about 20 μm, from about 1 μm to about 15 μm, from about 1 μm to about 10 μm, from about 5 μm to about 30 μm, from about 5 μm to about 25 μm, from about 5 μm to about 20 μm, from about 5 μm to about 15 μm, from about 5 μm to about 10 μm, from about 10 μm to about 30 μm, from about 10 μm to about 25 μm, from about 10 μm to about 20 μm, from about 10 μm to about 15 μm, from about 15 μm to about 30 μm, from about 15 μm to about 25 μm, from about 15 μm to about 20 μm, from about 20 μm to about 30 μm, from about 20 μm to about 25 μm, or any range or subrange therebetween.
In aspects, the coating can comprise a polymeric hard coating. In further aspects, the polymeric hard coating can comprise one or more of an ethylene-acid copolymer, a polyurethane-based polymer, an acrylate resin, and a mercapto-ester resin. Example aspects of ethylene-acid copolymers include ethylene-acrylic acid copolymers, ethylene-methacrylic acid copolymers, and ethylene-acrylic-methacrylic acid terpolymers (e.g., Nucrel, manufactured by DuPont), ionomers of ethylene acid copolymers (e.g., Surlyn, manufactured by DuPont), and ethylene-acrylic acid copolymer amine dispersions (e.g., Aquacer, manufactured by BYK). Example aspects of polyurethane-based polymers include aqueous modified polyurethane dispersions (e.g., Eleglas®, manufactured by Axalta). Example aspects of acrylate resins that can be UV curable include acrylate resins (e.g., Uvekol® resin, manufactured by Allinex), cyanoacrylate adhesives (e.g., Permabond® UV620, manufactured by Krayden), and UV radical acrylic resins (e.g., Ultrabond windshield repair resin, for example, Ultrabond (45CPS)). Example aspects of mercapto-ester resins include mercapto-ester triallyl isocyanurates (e.g., Norland optical adhesive NOA 61). In further aspects, the polymeric hard coating can comprise ethylene-acrylic acid copolymers and ethylene-methacrylic acid copolymers, which may be ionomerized to form ionomer resins through neutralization of the carboxylic acid residue with typically alkali-metal ions, for example, sodium and potassium, and also zinc. Such ethylene-acrylic acid and ethylene-methacrylic acid ionomers may be dispersed in water and coated onto the substrate to form an ionomer coating. Alternatively, such acid copolymers may be neutralized with ammonia which, after coating and drying liberates the ammonia to reform the acid copolymer as the coating. By providing a coating comprising a polymeric coating, the foldable apparatus can comprise low energy fracture.
In aspects, the coating can comprise a polymeric hard coating comprising an optically transparent polymeric hard-coat layer. Suitable materials for an optically transparent polymeric hard-coat layer include but are not limited to a cured acrylate resin material, an inorganic-organic hybrid polymeric material, an aliphatic or aromatic hexafunctional urethane acrylate, a siloxane-based hybrid material, and a nanocomposite material, for example, an epoxy and urethane material with nanosilicate. In aspects, an optically transparent polymeric hard-coat layer may consist essentially of one or more of these materials. In aspects, an optically transparent polymeric hard-coat layer may consist of one or more of these materials. As used herein, “inorganic-organic hybrid polymeric material” means a polymeric material comprising monomers with inorganic and organic components. An inorganic-organic hybrid polymer is obtained by a polymerization reaction between monomers having an inorganic group and an organic group. An inorganic-organic hybrid polymer is not a nanocomposite material comprising separate inorganic and organic constituents or phases, for example, inorganic particulates dispersed within an organic matrix. More specifically, suitable materials for an optically transparent polymeric (OTP) hard-coat layer include, but are not limited to, a polyimide, a polyethylene terephthalate (PET), a polycarbonate (PC), a poly methyl methacrylate (PMMA), organic polymer materials, inorganic-organic hybrid polymeric materials, and aliphatic or aromatic hexafunctional urethane acrylates. In aspects, an OTP hard-coat layer may consist essentially of an organic polymer material, an inorganic-organic hybrid polymeric material, or aliphatic or aromatic hexafunctional urethane acrylate. In aspects, an OTP hard-coat layer may consist of a polyimide, an organic polymer material, an inorganic-organic hybrid polymeric material, or aliphatic or aromatic hexafunctional urethane acrylate. In aspects, an OTP hard-coat layer may include a nanocomposite material. In aspects, an OTP hard-coat layer may include a nano-silicate at least one of epoxy and urethane materials. Suitable compositions for such an OTP hard-coat layer are described in U.S. Pat. Pub. No. 2015/0110990, which is hereby incorporated by reference in its entirety by reference thereto. As used herein, “organic polymer material” means a polymeric material comprising monomers with only organic components. In aspects, an OTP hard-coat layer may comprise an organic polymer material manufactured by Gunze Limited and having a hardness of 9H, for example Gunze's “Highly Durable Transparent Film.” As used herein, “inorganic-organic hybrid polymeric material” means a polymeric material comprising monomers with inorganic and organic components. An inorganic-organic hybrid polymer is obtained by a polymerization reaction between monomers having an inorganic group and an organic group. An inorganic-organic hybrid polymer is not a nanocomposite material comprising separate inorganic and organic constituents or phases, for example, inorganic particulates dispersed within an organic matrix. In aspects, the inorganic-organic hybrid polymeric material may include polymerized monomers comprising an inorganic silicon-based group, for example, a silsesquioxane polymer. A silsesquioxane polymer may be, for example, an alkyl-silsesquioxane, an aryl-silsesquioxane, or an aryl alkyl-silsesquioxane having the following chemical structure: (RSiO1.5)n, where R is an organic group for example, but not limited to, methyl or phenyl. In aspects, an OTP hard-coat layer may comprise a silsesquioxane polymer combined with an organic matrix, for example, SILPLUS manufactured by Nippon Steel Chemical Co., Ltd. In aspects, an OTP hard-coat layer may comprise 90 wt % to 95 wt % aromatic hexafunctional urethane acrylate (e.g., PU662NT (Aromatic hexafunctional urethane acrylate) manufactured by Miwon Specialty Chemical Co.) and 10 wt % to 5 wt % photo-initiator (e.g., Darocur 1173 manufactured by Ciba Specialty Chemicals Corporation) with a hardness of 8H or more. In aspects, an OTP hard-coat layer composed of an aliphatic or aromatic hexafunctional urethane acrylate may be formed as a stand-alone layer by spin-coating the layer on a polyethylene terephthalate (PET) substrate, curing the urethane acrylate, and removing the urethane acrylate layer from the PET substrate. In aspects, an OTP coating layer may be an aliphatic or aromatic hexafunctional urethane acrylate material layer having a thickness within one or more of the thickness ranges discussed above for the coating thickness.
In aspects, the coating, if provided, may also comprise one or more of an easy-to-clean coating, a low-friction coating, an oleophobic coating, a diamond-like coating, a scratch-resistant coating, or an abrasion-resistant coating. A scratch-resistant coating may comprise an oxynitride, for example, aluminum oxynitride or silicon oxynitride with a thickness of about 500 micrometers or more. In such aspects, the abrasion-resistant layer may comprise the same material as the scratch-resistant layer. In aspects, a low friction coating may comprise a highly fluorinated silane coupling agent, for example, an alkyl fluorosilane with oxymethyl groups pendant on the silicon atom. In such aspects, an easy-to-clean coating may comprise the same material as the low friction coating. In other aspects, the easy-to-clean coating may comprise a protonatable group, for example an amine, for example, an alkyl aminosilane with oxymethyl groups pendant on the silicon atom. In such aspects, the oleophobic coating may comprise the same material as the easy-to-clean coating. In aspects, a diamond-like coating comprises carbon and may be created by applying a high voltage potential in the presence of a hydrocarbon plasma.
Additionally, controlling properties of a first material (e.g., coating, polymer-based portion 241) positioned in a first recess can control the position of a neutral axis of the foldable apparatus and/or foldable substrates, which can reduce (e.g., mitigate, eliminate) the incidence of mechanical instabilities, apparatus fatigue, and/or apparatus failure. In aspects, a strain at yield of the polymer-based portion and/or adhesive layer can be about 5% or more, about 6% or more, about 7% or more, about 8% or more, about 9% or more, about 500% or less, about 100% or less, about 50% or less, about 20% or less, about 15% or less, about 12% or less, or about 10% or less. In aspects, the strain at yield of the polymer-based portion and/or adhesive layer can be in a range from about 5% to about 500%, from about 5% to about 100%, from about 6% to about 100%, from about 6% to about 50%, from about 7% to about 50%, from about 7% to about 20%, from about 8% to about 20%, from about 8% to about 15%, from about 9% to about 15%, from about 9% to about 10%, from about 5% to about 15%, from about 5% to about 10%, or any range or subrange therebetween.
In aspects, as shown in
In aspects, as shown in
Aspects of the disclosure can comprise a consumer electronic product. The consumer electronic product can comprise a front surface, a back surface, and side surfaces. The consumer electronic product can further comprise electrical components at least partially within the housing. The electrical components can comprise a controller, a memory, and a display. The display can be at or adjacent to the front surface of the housing. The display can comprise a liquid crystal display (LCD), an electrophoretic display (EPD), an organic light-emitting diode (OLED) display, or a plasma display panel (PDP). The consumer electronic product can comprise a cover substrate disposed over the display. In aspects, at least one of a portion of the housing or the cover substrate comprises the foldable apparatus discussed throughout the disclosure. The consumer electronic product can comprise a portable electronic device, for example, a smartphone, a tablet, a wearable device, or a laptop.
The foldable apparatus disclosed herein may be incorporated into another article, for example, an article with a display (or display articles) (e.g., consumer electronics, including mobile phones, tablets, computers, navigation systems, wearable devices (e.g., watches), and the like), architectural articles, transportation articles (e.g., automotive, trains, aircraft, sea craft, etc.), appliance articles, or any article that may benefit from some transparency, scratch-resistance, abrasion resistance or a combination thereof. An exemplary article incorporating any of the foldable apparatus disclosed herein is shown in
In aspects, the foldable substrate 201 can comprise a glass-based substrate and/or a ceramic-based substrate, and the first portion 221, the second portion 231, and/or the central portion 281 can comprise one or more compressive stress regions. In aspects, a compressive stress region may be created by chemically strengthening. Chemically strengthening may comprise an ion exchange process, where ions in a surface layer are replaced by—or exchanged with—larger ions having the same valence or oxidation state. Methods of chemically strengthening will be discussed later. Without wishing to be bound by theory, chemically strengthening the first portion 221, the second portion 231, and/or the central portion 281 can enable good impact and/or puncture resistance (e.g., resists failure for a pen drop height of about 15 centimeters (cm) or more, about 20 cm or more, about 50 cm or more). Without wishing to be bound by theory, chemically strengthening the first portion 221, the second portion 231, and/or the central portion 281 can enable small (e.g., smaller than about 10 mm or less) bend radii because the compressive stress from the chemical strengthening can counteract the bend-induced tensile stress on the outermost surface of the substrate. A compressive stress region may extend into a portion of the first portion and/or the second portion for a depth called the depth of compression. As used herein, depth of compression means the depth at which the stress in the chemically strengthened substrates and/or portions described herein changes from compressive stress to tensile stress. Depth of compression may be measured by a surface stress meter or a scattered light polariscope (SCALP, wherein values reported herein were made using SCALP-5 made by Glasstress Co., Estonia) depending on the ion exchange treatment and the thickness of the article being measured. Where the stress in the substrate and/or portion is generated by exchanging potassium ions into the substrate, a surface stress meter, for example, the FSM-6000 (Orihara Industrial Co., Ltd. (Japan)), is used to measure depth of compression. Unless specified otherwise, compressive stress (including surface CS) is measured by surface stress meter (FSM) using commercially available instruments, for example the FSM-6000, manufactured by Orihara. Surface stress measurements rely upon the accurate measurement of the stress optical coefficient (SOC), which is related to the birefringence of the glass. Unless specified otherwise, SOC is measured according to Procedure C (Glass Disc Method) described in ASTM standard C770-16, entitled “Standard Test Method for Measurement of Glass Stress-Optical Coefficient,” the contents of which are incorporated herein by reference in their entirety. Where the stress is generated by exchanging sodium ions into the substrate, and the article being measured is thicker than about 400 μm, SCALP is used to measure the depth of compression and central tension (CT). Where the stress in the substrate and/or portion is generated by exchanging both potassium and sodium ions into the substrate and/or portion, and the article being measured is thicker than about 400 μm, the depth of compression and CT are measured by SCALP. Without wishing to be bound by theory, the exchange depth of sodium may indicate the depth of compression while the exchange depth of potassium ions may indicate a change in the magnitude of the compressive stress (but not the change in stress from compressive to tensile). The refracted near-field (RNF; the RNF method is described in U.S. Pat. No. 8,854,623, entitled “Systems and methods for measuring a profile characteristic of a glass sample”, which is incorporated herein by reference in its entirety) method also may be used to derive a graphical representation of the stress profile. When the RNF method is utilized to derive a graphical representation of the stress profile, the maximum central tension value provided by SCALP is utilized in the RNF method. The graphical representation of the stress profile derived by RNF is force balanced and calibrated to the maximum central tension value provided by a SCALP measurement. As used herein, “depth of layer” (DOL) means the depth that the ions have exchanged into the substrate and/or portion (e.g., sodium, potassium). Through the disclosure, when the maximum central tension cannot be measured directly by SCALP (as when the article being measured is thinner than about 400 μm) the maximum central tension can be approximated by a product of a maximum compressive stress and a depth of compression divided by the difference between the thickness of the substrate and twice the depth of compression, wherein the compressive stress and depth of compression are measured by FSM.
In aspects, the first portion 221 comprising the glass-based portion and/or ceramic-based portion may comprise a first compressive stress region at the first surface area 223 that can extend to a first depth of compression from the first surface area 223. In aspects, the first portion 221 comprising a first glass-based and/or ceramic-based portion may comprise a second compressive stress region at the second surface area 225 that can extend to a second depth of compression from the second surface area 225. In aspects, the first depth of compression and/or the second depth of compression as a percentage of the substrate thickness 207 can be about 1% or more, about 5% or more, about 10% or more, about 30% or less, about 25% or less, or about 20% or less. In aspects, the first depth of compression and/or the second depth of compression as a percentage of the substrate thickness 207 can be in a range from about 1% to about 30%, from about 5% to about 30%, from about 5% to about 25%, from about 5% to about 20%, from about 10% to about 30%, from about 10% to about 25%, from about 10% to about 20%, or any range or subrange therebetween. In further aspects, the first depth of compression and/or the second depth of compression as a percentage of the substrate thickness 207 can be about 10% or less, for example, from about 1% to about 10%, from about 1% to about 8%, from about 3% to about 8%, from about 5% to about 8%, or any range or subrange therebetween. In further aspects, the first depth of compression can be substantially equal to the second depth of compression. In aspects, the first depth of compression and/or the second depth of compression can be about 1 μm or more, about 10 μm or more, about 30 μm or more, about 50 μm or more, about 200 μm or less, about 150 μm or less, about 100 μm or less, or about 60 μm or less. In aspects, the first depth of compression and/or the second depth of compression can be in a range from about 1 μm to about 200 μm, from about 1 μm to about 150 μm, from about 10 μm to about 150 μm, from about 10 μm to about 100 μm, from about 30 μm to about 100 μm, from about 30 μm to about 60 μm, from about 50 μm to about 60 μm, or any range or subrange therebetween. By providing a first portion comprising a first glass-based and/or ceramic-based portion comprising a first depth of compression and/or a second depth of compression in a range from about 1% to about 30% of the first thickness, good impact and/or puncture resistance can be enabled.
In aspects, the first compressive stress region can comprise a maximum first compressive stress. In aspects, the second compressive stress region can comprise a maximum second compressive stress. In further aspects, the maximum first compressive stress and/or the maximum second compressive stress can be about 100 MegaPascals (MPa) or more, about 300 MPa or more, about 500 MPa or more, about 600 MPa or more, about 700 MPa or more, about 1,500 MPa or less, about 1,200 MPa or less, about 1,000 MPa or less, or about 800 MPa or less. In further aspects, the maximum first compressive stress and/or the maximum second compressive stress can be in a range from about 100 MPa to about 1,500 MPa, from about 100 MPa to about 1,200 MPa, from about 300 MPa to about 1,200 MPa, from about 300 MPa to about 1,000 MPa, from about 500 MPa to about 1,000 MPa, from about 600 MPa to about 1,000 MPa, from about 600 MPa to about 1,000 MPa, from about 700 MPa to about 1,000 MPa, from about 700 MPa to about 800 MPa, from about 500 MPa to about 800 MPa, or any range or subrange therebetween. By providing a maximum first compressive stress and/or a maximum second compressive stress in a range from about 100 MPa to about 1,500 MPa, good impact and/or puncture resistance can be enabled.
In aspects, the first portion 221 can comprise a first depth of layer of one or more alkali-metal ions associated with the first compressive stress region. In aspects, the first portion 221 can comprise a second depth of layer of one or more alkali-metal ions associated with the second compressive stress region and the second depth of compression. As used herein, the one or more alkali-metal ions of a depth of layer of one or more alkali-metal ions can include sodium, potassium, rubidium, cesium, and/or francium. In aspects, the one or more alkali ions of the first depth of layer of the one or more alkali ions and/or the second depth of layer of the one or more alkali ions comprises potassium. In aspects, the first depth of layer and/or the second depth of layer as a percentage of the substrate thickness 207 can be about 1% or more, about 5% or more, about 10% or more, about 40% or less, about 35% or less, about 30% or less, about 25% or less, or about 20% or less. In aspects, the first depth of layer and/or the second depth of layer as a percentage of the substrate thickness 207 can be in a range from about 1% to about 40%, from about 1% to about 35%, from about 1% to about 30%, from about 1% to about 25%, from about 1% to about 20%, from about 5% to about 30%, from about 5% to about 25%, from about 5% to about 20%, from about 10% to about 30%, from about 10% to about 25%, from about 10% to about 20%, or any range or subrange therebetween. In further aspects, the first depth of layer of the one or more alkali-metal ions and/or the second depth of layer of the one or more alkali-metal ions as a percentage of the substrate thickness 207 can be about 10% or less, for example, from about 1% to about 10%, from about 1% to about 8%, from about 3% to about 8%, from about 5% to about 8%, or any range or subrange therebetween. In aspects, the first depth of layer of the one or more alkali-metal ions and/or the second depth of layer of the one or more alkali-metal ions can be about 1 μm or more, about 10 μm or more, about 30 μm or more, about 50 μm or more, about 200 μm or less, about 150 μm or less, about 100 μm or less, or about 60 μm or less. In aspects, the first depth of layer of the one or more alkali-metal ions and/or the second depth of layer of the one or more alkali-metal ions can be in a range from about 1 μm to about 200 μm, from about 1 μm to about 150 μm, from about 10 μm to about 150 μm, from about 10 μm to about 100 μm, from about 30 μm to about 100 μm, from about 30 μm to about 60 μm, from about 50 μm to about 60 μm, or any range or subrange therebetween.
In aspects, the first portion 221 may comprise a first tensile stress region. In aspects, the first tensile stress region can be positioned between the first compressive stress region and the second compressive stress region. In aspects, the first tensile stress region can comprise a maximum first tensile stress. In further aspects, the maximum first tensile stress can be about 10 MPa or more, about 20 MPa or more, about 30 MPa or more, about 100 MPa or less, about 80 MPa or less, or about 60 MPa or less. In further aspects, the maximum first tensile stress can be in a range from about 10 MPa to about 100 MPa, from about 10 MPa to about 80 MPa, from about 10 MPa to about 60 MPa, from about 20 MPa to about 100 MPa, from about 20 MPa to about 80 MPa, from about 20 MPa to about 60 MPa, from about 30 MPa to about 100 MPa, from about 30 MPa to about 80 MPa, from about 30 MPa to about 60 MPa, or any range or subrange therebetween. Providing a maximum first tensile stress in a range from about 10 MPa to about 100 MPa can enable good impact and/or puncture resistance while providing low energy fractures, as discussed below.
In aspects, the second portion 231 comprising a second glass-based and/or ceramic-based portion may comprise a third compressive stress region at the third surface area 233 that can extend to a third depth of compression from the third surface area 233. In aspects, the second portion 231 comprising a second glass-based and/or ceramic-based portion may comprise a fourth compressive stress region at the fourth surface area 235 that can extend to a fourth depth of compression from the fourth surface area 235. In aspects, the third depth of compression and/or the fourth depth of compression as a percentage of the substrate thickness 207 can be about 1% or more, about 5% or more, about 10% or more, about 30% or less, about 25% or less, or about 20% or less. In aspects, the third depth of compression and/or the fourth depth of compression as a percentage of the substrate thickness 207 can be within one or more of the ranges discussed above for the first depth of compression and/or the second depth of compression as a percentage of the substrate thickness 207. In further aspects, the third depth of compression can be substantially equal to the fourth depth of compression. In aspects, the third depth of compression and/or the fourth depth of compression can be within one or more of the ranges discussed above for the first depth of compression and/or the second depth of compression. By providing a second portion comprising a glass-based and/or ceramic-based portion comprising a third depth of compression and/or a fourth depth of compression in a range from about 1% to about 30% of the substrate thickness, good impact and/or puncture resistance can be enabled.
In aspects, the third compressive stress region can comprise a maximum third compressive stress. In aspects, the fourth compressive stress region can comprise a maximum fourth compressive stress. In further aspects, the maximum third compressive stress and/or the maximum fourth compressive stress can be within one or more of the ranges discussed above for the maximum first compressive stress and/or the maximum second compressive stress. By providing a maximum third compressive stress and/or a maximum fourth compressive stress in a range from about 100 MPa to about 1,500 MPa, good impact and/or puncture resistance can be enabled.
In aspects, the second portion 231 can comprise a third depth of layer of one or more alkali-metal ions associated with the third compressive stress region and the third depth of compression. In aspects, the second portion 231 can comprise a fourth depth of layer of one or more alkali-metal ions associated with the fourth compressive stress region and the fourth depth of compression. In aspects, the one or more alkali ions of the third depth of layer of the one or more alkali ions and/or the fourth depth of layer of the one or more alkali ions comprises potassium. In aspects, the third depth of layer and/or the fourth depth of layer as a percentage of the substrate thickness 207 can be within one or more of the ranges discussed above for the first depth of layer and/or the second depth of layer as a percentage of the substrate thickness 207. In aspects, the third depth of layer of the one or more alkali-metal ions and/or the fourth depth of layer of the one or more alkali-metal ions can be equal to the first depth of layer and/or the second depth of layer.
In aspects, the second portion 231 may comprise a second tensile stress region. In aspects, the second tensile stress region can be positioned between the third compressive stress region and the fourth compressive stress region. In aspects, the second tensile stress region can comprise a maximum second tensile stress. In further aspects, the maximum second tensile stress can be within one or more of the ranges discussed above for the maximum first tensile stress. In aspects, the maximum first tensile stress can be substantially equal to the maximum second tensile stress. Providing a maximum second tensile stress in a range from about 10 MPa to about 100 MPa can enable good impact and/or puncture resistance while providing low energy fractures, as discussed below.
In aspects, the first depth of compression can be substantially equal to the third depth of compression. In aspects, the second depth of compression can be substantially equal to the fourth depth of compression. In aspects, the maximum first compressive stress can be substantially equal to the maximum third compressive stress. In aspects, the maximum second compressive stress can be substantially equal to the maximum fourth compressive stress. In aspects, the first depth of layer of one or more alkali-metal ions can be substantially equal to the third depth of layer of one or more alkali-metal ions. In aspects, the second depth of layer of one or more alkali-metal ions can be substantially equal to the fourth depth of layer of one or more alkali-metal ions.
In aspects, the central portion (e.g., the central region) can be substantially unstrengthened (e.g., unstressed, not chemically strengthened, not thermally strengthened) with substantially no tensile stress region or a small magnitude maximum tensile stress. As used herein, substantially unstrengthened refers to a substrate comprising either no depth of layer or a depth of layer in a range from 0% to about 5% of the substrate thickness. In further aspects, the central region can be substantially unstrengthened while the first transition portion and/or the second transition portion can be chemically strengthened.
In aspects, the central portion 281 (e.g., central region 248) can comprise a first central compressive stress region at the first central surface area 211 that can extend to a first central depth of compression from the first central surface area 211. In aspects, the central portion 281 (e.g., central region 248) can comprise a second central compressive stress region at the second central surface area 213 that can extend to a second central depth of compression from the second central surface area 213. In further aspects, the first central compressive stress region and/or the second compressive stress region can be within the central region 248 of the central portion 281 (e.g., coextensive with the first central surface area 211 and/or the second central surface area 213). In further aspects, the first central depth of compression and/or the second central depth of compression as a percentage of the central thickness 217 can be within one or more of the ranges discussed above for the first depth of compression and/or the second depth of compression as a percentage of the substrate thickness 207. In further aspects, the first central depth of compression and/or the second central depth of compression as a percentage of the central thickness 217 can be about 10% or more, for example, from about 10% to about 30%, from about 10% to about 25%, from about 15% to about 25%, from about 15% to about 20%, or any range or subrange therebetween. In further aspects, the first central depth of compression can be substantially equal to the second central depth of compression. In aspects, the first central depth of compression and/or the second central depth of compression can be within one or more of the ranges discussed above for the first depth of compression and/or the second depth of compression. By providing a central portion comprising a glass-based and/or ceramic-based portion comprising a first central depth of compression and/or a second central depth of compression in a range from about 1% to about 30% of the central thickness, good impact and/or puncture resistance can be enabled.
In aspects, the first central compressive stress region can comprise a maximum first central compressive stress. In aspects, the second central compressive stress region can comprise a maximum second central compressive stress. In further aspects, the maximum first central compressive stress and/or the maximum second central compressive stress can be within one or more of the ranges discussed above for the maximum first compressive stress and/or the maximum second compressive stress. By providing a maximum first central compressive stress and/or a maximum second central compressive stress of about 500 MPa or more or in a range from about 100 MPa to about 1,500 MPa, good impact and/or puncture resistance can be enabled.
In aspects, the central portion 281 can comprise a first central depth of layer of one or more alkali-metal ions associated with the first central compressive stress region and the first central depth of compression. In aspects, the central portion 281 can comprise a second central depth of layer of one or more alkali-metal ions associated with the second central compressive stress region and the second central depth of compression. In aspects, the one or more alkali ions of the first central depth of layer of the one or more alkali ions and/or the second central depth of layer of the one or more alkali ions comprises potassium. In aspects, the first central depth of layer and/or the second central depth of layer as a percentage of the central thickness 217 can be within one or more of the ranges discussed above for the first depth of layer and/or the second depth of layer as a percentage of the substrate thickness 207. In aspects, the first central depth of layer of the one or more alkali-metal ions and/or the second central depth of layer of the one or more alkali-metal ions can be within one or more of the ranges discussed above for the first depth of layer and/or the second depth of layer. In aspects, the first depth of compression and/or the third depth of compression can be greater than the first central depth of compression. In aspects, the second depth of compression and/or the fourth depth of compression can be greater than the second central depth of compression. In aspects, the first depth of layer and/or the third depth of layer can be greater than the first central depth of layer. In aspects, the second depth of layer and/or the fourth depth of layer can be greater than the second central depth of layer.
In aspects, the central portion 281 may comprise a central tensile stress region. In aspects, the central tensile stress region can be positioned between the first central compressive stress region and the second central compressive stress region. In aspects, the central tensile stress region can comprise a maximum central tensile stress. In further aspects, the maximum central tensile stress can be about 125 MPa or more, about 150 MPa or more, about 200 MPa or more, about 375 MPa or less, about 300 MPa or less, or about 250 MPa or less. In further aspects, the maximum central tensile stress can be in a range from about 125 MPa to about 375 MPa, from about 125 MPa to about 300 MPa, from about 125 MPa to about 250 MPa, from about 150 MPa to about 375 MPa, from about 150 MPa to about 300 MPa, from about 150 MPa to about 250 MPa, from about 200 MPa to about 375 MPa, from about 200 MPa to about 300 MPa, from about 200 MPa to about 250 MPa, or any range or subrange therebetween. Providing a maximum central tensile stress in a range from about 125 MPa to about 375 MPa can enable low minimum bend radii.
In aspects, the first transition region 212 can comprise a first transition compressive stress region at the first transition surface area 283 that can extend to a first transition depth of compression from the first transition surface area 283. In aspects, the second transition region 218 can comprise a second transition compressive stress region at the second transition surface area 285 that can extend to a second transition depth of compression from the second transition surface area 285. In further aspects, the first transition depth of compression can be substantially equal to the second transition depth of compression. In aspects, the first transition depth of compression and/or the second transition depth of compression can be within one or more of the ranges discussed above for the first depth of compression and/or the second depth of compression. In aspects, the first transition compressive stress region can comprise a maximum first transition compressive stress. In aspects, the second transition compressive stress region can comprise a maximum second transition compressive stress. In further aspects, the maximum first transition compressive stress and/or the maximum second transition compressive stress can be within one or more of the ranges discussed above for the maximum first compressive stress and/or the maximum second compressive stress.
In aspects, the first transition region 212 can comprise a first transition depth of layer of one or more alkali-metal ions associated with the first transition compressive stress region and the first depth of compression. In aspects, the second transition region 218 can comprise a second transition depth of layer of one or more alkali-metal ions associated with the second transition compressive stress region and the second depth of compression. In aspects, the one or more alkali ions of the first transition depth of layer of the one or more alkali ions and/or the second transition depth of layer of the one or more alkali ions comprises potassium. In aspects, the first transition depth of layer of the one or more alkali-metal ions and/or the second transition depth of layer of the one or more alkali-metal ions can be within one or more of the ranges discussed above for the first depth of layer and/or the second depth of layer. In aspects, the first transition region 212 may comprise a first transition tensile stress region. In aspects, the second transition region 218 may comprise a second transition tensile stress region. In aspects, the first transition tensile stress region can comprise a maximum first transition tensile stress. In aspects, the second transition tensile stress region can comprise a maximum second transition tensile stress. In further aspects, the maximum first transition tensile stress and/or the maximum second transition tensile stress can be within one or more of the ranges discussed above for the maximum central tensile stress.
In aspects, the maximum first transition tensile stress can be greater than or equal to the maximum central tensile stress. In further aspects, the maximum first transition tensile stress can be less than or equal to the maximum first tensile stress of the first tensile stress region. In further aspects, the maximum first tensile stress of the first tensile stress region can be greater than or equal to the maximum central tensile stress. In aspects, the maximum second transition tensile stress can be greater than or equal to the maximum central tensile stress. In further aspects, the maximum second transition tensile stress can be less than or equal to the maximum second tensile stress of the second tensile stress region. In further aspects, the maximum second tensile stress of the second tensile stress region can be greater than or equal to the maximum central tensile stress. Providing a maximum first transition tensile stress and/or a maximum second transition tensile stress greater than or equal to a maximum central tensile stress can reduce the incidence of mechanical instabilities (e.g., of the central portion).
In aspects, the first depth of compression as a percentage of the substrate thickness can be greater than or equal to the first central depth of compression as a percentage of the central thickness. In even further aspects, the third depth of compression as a percentage of the substrate thickness can be greater than or equal to the first central depth of compression as a percentage of the central thickness. In aspects, the second depth of compression as a percentage of the substrate thickness can be greater than or equal to the second central depth of compression as a percentage of the central thickness. In further aspects, the fourth depth of compression as a percentage of the substrate thickness can be greater than or equal to the second central depth of compression as a percentage of the central thickness.
In aspects, the first depth of layer as a percentage of the substrate thickness can be greater than or equal to the first central depth of layer as a percentage of the central thickness. In even further aspects, the third depth of layer as a percentage of the substrate thickness can be greater than or equal to the first central depth of layer as a percentage of the central thickness. In aspects, the second depth of layer as a percentage of the substrate thickness can be greater than or equal to the second central depth of layer as a percentage of the central thickness. In further aspects, the fourth depth of layer as a percentage of the substrate thickness can be greater than or equal to the second central depth of layer as a percentage of the central thickness.
In aspects, the polymer-based portion 241 can be optically clear. The polymer-based portion 241 can comprise a first index of refraction. The first refractive index may be a function of a wavelength of light passing through the optically clear adhesive. For light of a first wavelength, a refractive index of a material is defined as the ratio between the speed of light in a vacuum and the speed of light in the corresponding material. Without wishing to be bound by theory, a refractive index of the optically clear adhesive can be determined using a ratio of a sine of a first angle to a sine of a second angle, where light of the first wavelength is incident from air on a surface of the optically clear adhesive at the first angle and refracts at the surface of the optically clear adhesive to propagate light within the optically clear adhesive at a second angle. The first angle and the second angle are both measured relative to a direction normal to a surface of the optically clear adhesive. As used herein, the refractive index is measured in accordance with ASTM E1967-19, where the first wavelength comprises 589 nm. In aspects, the first refractive index of the polymer-based portion 241 may be about 1 or more, about 1.3 or more, about 1.4 or more, about 1.45 or more, about 1.49 or more, about 3 or less, about 2 or less, or about 1.7 or less, about 1.6 or less, or about 1.55 or less. In aspects, the first refractive index of the polymer-based portion 241 can be in a range from about 1 to about 3, from about 1 to about 2 from about 1 to about 1.7, from about 1.3 to about 1.7, from about 1.4 to about 1.7, from about 1.4 to about 1.6, from about 1.45 to about 1.55, from about 1.49 to about 1.55, or any range or subrange therebetween.
In aspects, the foldable substrate 201 can comprise a second index of refraction. In aspects, the second refractive index of the foldable substrate 201 may be about 1 or more, about 1.3 or more, about 1.4 or more, about 1.45 or more, about 1.49 or more, about 3 or less, about 2 or less, or about 1.7 or less, about 1.6 or less, or about 1.55 or less. In aspects, the second refractive index of the foldable substrate 201 can be in a range from about 1 to about 3, from about 1 to about 2 from about 1 to about 1.7, from about 1.3 to about 1.7, from about 1.4 to about 1.7, from about 1.4 to about 1.6, from about 1.45 to about 1.55, from about 1.49 to about 1.55, or any range or subrange therebetween. In aspects, a differential equal to the absolute value of the difference between the second index of refraction of the foldable substrate 201 and the first index of refraction of the polymer-based portion 241 can be about 0.1 or less, about 0.07 or less, about 0.05 or less, about 0.001 or more, about 0.01 or more, or about 0.02 or more. In aspects, the differential is in a range from about 0.001 to about 0.1, from about 0.001 to about 0.07, from about 0.001 to about 0.05, from about 0.01 to about 0.1, from about 0.01 to about 0.07, from about 0.01 to about 0.05, from about 0.02 to about 0.1, from about 0.02 to about 0.07, from about 0.02 to about 0.05, or any range or subrange therebetween. In aspects, the second index of refraction of the foldable substrate 201 may be greater than the first index of refraction of the polymer-based portion 241. In aspects, the second index of refraction of the foldable substrate 201 may be less than the first index of refraction of the polymer-based portion 241.
In aspects, the adhesive layer 261 can comprise a third index of refraction. In aspects, the third index of refraction of the adhesive layer 261 can be within one or more of the ranges discussed above with regards to the first index of refraction of the polymer-based portion 241. In aspects, a differential equal to the absolute value of the difference between the third index of refraction of the adhesive layer 261 and the first index of refraction of the polymer-based portion 241 can be about 0.1 or less, about 0.07 or less, about 0.05 or less, about 0.001 or more, about 0.01 or more, or about 0.02 or more. In aspects, the differential is in a range from about 0.001 to about 0.1, from about 0.001 to about 0.07, from about 0.001 to about 0.05, from about 0.01 to about 0.1, from about 0.01 to about 0.07, from about 0.01 to about 0.05, from about 0.02 to about 0.1, from about 0.02 to about 0.07, from about 0.02 to about 0.05, or any range or subrange therebetween. In aspects, the third index of refraction of the adhesive layer 261 may be greater than the first index of refraction of the polymer-based portion 241. In aspects, the third index of refraction of the adhesive layer 261 may be less than the first index of refraction of the polymer-based portion 241.
In aspects, a differential equal to the absolute value of the difference between the third index of refraction of the adhesive layer 261 and the second index of refraction of the foldable substrate 201 can be about 0.1 or less, about 0.07 or less, about 0.05 or less, about 0.001 or more, about 0.01 or more, or about 0.02 or more. In aspects, the differential is in a range from about 0.001 to about 0.1, from about 0.001 to about 0.07, from about 0.001 to about 0.05, from about 0.01 to about 0.1, from about 0.01 to about 0.07, from about 0.01 to about 0.05, from about 0.02 to about 0.1, from about 0.02 to about 0.07, from about 0.02 to about 0.05, or any range or subrange therebetween. In aspects, the third index of refraction of the adhesive layer 261 may be greater than the second index of refraction of the foldable substrate 201. In aspects, the third index of refraction of the adhesive layer 261 may be less than the second index of refraction of the foldable substrate 201.
As used herein, “foldable” includes complete folding, partial folding, bending, flexing, or multiple capabilities. As used herein, the terms “fail,” “failure” and the like refer to breakage, destruction, delamination, or crack propagation. Likewise, a foldable apparatus achieves a parallel plate distance of “X,” or has a parallel plate distance of “X,” or comprises a parallel plate distance of “X” if it resists failure when the foldable apparatus is held at a parallel plate distance of “X” for 24 hours at about 85° C. and about 85% relative humidity.
As used herein, the “parallel plate distance” of a foldable apparatus and/or foldable substrate is measured with the following test configuration and process using a parallel plate apparatus 801 (see
For determining a “parallel plate distance”, the distance between the parallel plates is reduced at a rate of 50 μm/second until the parallel plate distance 811 or 911 is equal to the “parallel plate distance” to be tested. Then, the parallel plates are held at the “parallel plate distance” to be tested for 24 hours at about 85° C. and about 85% relative humidity. As used herein, the “minimum parallel plate distance” is the smallest parallel plate distance that the foldable apparatus can withstand without failure under the conditions and configuration described above.
In aspects, the foldable apparatus 101, 301, 401, 701, 901, and/or 1001 can achieve a parallel plate distance of 100 mm or less, 50 mm or less, 20 mm or less, 10 mm or less, 5 mm or less, or 3 mm or less. In further aspects, the foldable apparatus 101, 301, 401, 701, 901, and/or 1001 can achieve a parallel plate distance of 50 millimeters (mm), or 20 mm, or 10 mm, of 5 mm, or 3 mm. In aspects, the foldable apparatus 101, 301, 401, 701, 901, and/or 1001 can comprise a minimum parallel plate distance of about 40 mm or less, about 20 mm or less, about 10 mm or less, about 5 mm or less, about 3 mm or less, about 1 mm or less, about 1 mm or more, about 3 mm or more, about 5 mm or more, or about 10 mm or more. In aspects, the foldable apparatus 101, 301, 401, 701, 901, and/or 1001 can comprise a minimum parallel plate distance in a range from about 1 mm to about 40 mm, from about 1 mm to about 20 mm, from about 1 mm to about 10 mm, from about 1 mm to about 5 mm, from about 1 mm to about 3 mm. In aspects, the foldable apparatus 101, 301, 401, 701, 901, and/or 1001 can achieve a minimum parallel plate distance in a range from about 2 mm to about 40 mm, from about 2 mm to about 20 mm, from about 2 mm to about 10 mm, from about 3 mm to about 10 mm, from about 3 mm to about 5 mm, from about 5 mm to about 10 mm, or any range or subrange therebetween.
A width 282 of the central portion 281 of the foldable substrate 201 is defined between the first portion 221 and the second portion 231 in the direction 106 of the length 105. In aspects, the width 282 of the central portion 281 of the foldable substrate 201 can extend from the first portion 221 to the second portion 231. A width 282 of the first central surface area 211 of the foldable substrate 201 is defined between the first transition region 212 and the second transition region 218, for example, as the portion comprising the central thickness 217, in the direction 106 of the length 105. In aspects, the width 282 of the central portion 281 of the foldable substrate 201 and/or the width 282 of the first central surface area 211 of the foldable substrate 201 can be about 1.4 times or more, about 1.6 times or more, about 2 times or more, about 2.2 times or more, about 3 times or less, or about 2.5 times or less the minimum parallel plate distance. In aspects, the width 282 of the central portion 281 of the foldable substrate 201 and/or the width 282 of the first central surface area 211 of the foldable substrate 201 as a multiple of the minimum parallel plate distance can be in a range from about 1.4 times to about 3 times, from about 1.6 times to about 3 times, from about 1.6 times to about 2.5 times, from about 2 times to about 2.5 times, from about 2.2 times to about 2.5 times, from about 2.2 times to about 3 times, or any range or subrange therebetween. Without wishing to be bound by theory, the length of a bent portion in a circular configuration between parallel plates can be about 1.6 times the parallel plate distance 811 or 911. Without wishing to be bound by theory, the length of a bend portion in an elliptical configuration between parallel plates can be about 2.2 times the parallel plate distance 811 or 911. In aspects, the width 282 of the central portion 281 of the foldable substrate 201 and/or the width 282 of the first central surface area 211 of the foldable substrate 201 can be about 1 mm or more, about 3 mm or more, about 5 mm or more, about 8 mm or more, about 10 mm or more, about 15 mm or more, about 20 mm or more, about 100 mm or less, about 60 mm or less, about 50 mm or less, about 40 mm or less, about 35 mm or less, about 30 mm or less, or about 25 mm or less. In aspects, the width 282 of the central portion 281 of the foldable substrate 201 and/or the width 282 of the first central surface area 211 of the foldable substrate 201 can be in a range from about 1 mm to about 100 mm, from about 3 mm to about 100 mm, from about 3 mm to about 60 mm, from about 5 mm to about 60 mm, from about 5 mm to about 50 mm, from about 8 mm to about 50 mm, from about 8 mm to about 40 mm, from about 10 mm to about 40 mm, from about 10 mm to about 35 mm, from about 15 mm to about 35 mm, from about 15 mm to about 30 mm, from about 20 mm to about 30 mm, from about 20 mm to about 25 mm, or any range of subrange therebetween. In aspects, the width 282 of the central portion 281 of the foldable substrate 201 and/or the width 282 of the first central surface area 211 of the foldable substrate 201 can be about 2.8 mm or more, about 6 mm or more, about 9 mm or more, about 60 mm or less, about 40 mm, or less, or about 24 mm or less. In aspects, the width 282 of the central portion 281 of the foldable substrate 201 and/or the width 282 of the first central surface area 211 of the foldable substrate 201 can be in a range from about 2.8 mm to about 60 mm, from about 2.8 mm to about 40 mm, from about 2.8 mm to about 24 mm, from about 6 mm to about 60 mm, from about 6 mm to about 40 mm, from about 6 mm to about 24 mm, from about 9 mm to about 60 mm, from about 9 mm to about 40 mm, from about 9 mm to about 24 mm, or any range of subrange therebetween. By providing a width within the above-noted ranges for the central portion (e.g., between the first portion and the second portion), folding of the foldable apparatus without failure can be facilitated.
The foldable apparatus 101, 301, 401, 701, 901, and/or 1001 may have an impact resistance defined by the capability of a region of the foldable apparatus (e.g., a region comprising the first portion 221, a region comprising the second portion 231, a region comprising the polymer-based portion 241 and/or central portion 281) to avoid failure at a pen drop height (e.g., 5 centimeters (cm) or more, 10 centimeters or more, 20 cm or more), when measured according to the “Pen Drop Test.” As used herein, the “Pen Drop Test” is conducted such that samples of foldable apparatus are tested with the load (i.e., from a pen dropped from a certain height) imparted to a major surface (e.g., second major surface 205 of the foldable substrate 201) configured as in the parallel plate test with 100 μm thick sheet 907 of PET attached to the test adhesive layer 909 having a thickness of 50 μm instead of the release liner 271 shown in
A tube is used for the Pen Drop Test to guide a pen to an outer surface of the foldable apparatus. For the foldable apparatus 101, 301, 401, 701, 901, and/or 1001 illustrated in
For the Pen Drop Test, the pen is dropped with the cap attached to the top end (i.e., the end opposite the tip) so that the ballpoint can interact with the test sample. In a drop sequence according to the Pen Drop Test, one pen drop is conducted at an initial height of 1 cm, followed by successive drops in 0.5 cm increments up to 20 cm, and then after 20 cm, 2 cm increments until failure of the test sample. After each drop is conducted, the presence of any observable fracture, failure, or other evidence of damage to the sample is recorded along with the particular pen drop height. Using the Pen Drop Test, multiple samples can be tested according to the same drop sequence to generate a population with improved statistical accuracy. For the Pen Drop Test, the pen is to be changed to a new pen after every 5 drops, and for each new sample tested. In addition, all pen drops are conducted at random locations on the sample at or near the center of the sample, with no pen drops near or on the edge of the samples.
For purposes of the Pen Drop Test, “failure” means the formation of a visible mechanical defect in a laminate. The mechanical defect may be a crack or plastic deformation (e.g., surface indentation). The crack may be a surface crack or a through crack. The crack may be formed on an interior or exterior surface of a laminate. The crack may extend through all or a portion of the foldable substrate 201 and/or coating. A visible mechanical defect has a minimum dimension of 0.2 mm or more.
In aspects, the foldable apparatus can resist failure for a pen drop in a region comprising the first portion 221 or the second portion 231 at a pen drop height of 10 centimeters (cm), 12 cm, 14 cm, 16 cm, or 20 cm. In aspects, a maximum pen drop height that the foldable apparatus can withstand without failure over a region comprising the first portion 221 or the second portion 231 may be about 10 cm or more, about 12 cm or more, about 14 cm or more, about 16 cm or more, about 40 cm or less, or about 30 cm or less, about 20 cm or less, about 18 cm or less. In aspects, a maximum pen drop height that the foldable apparatus can withstand without failure over a region comprising the first portion 221 or the second portion 231 can be in a range from about 10 cm to about 40 cm, from about 12 cm to about 40 cm, from about 12 cm to about 30 cm, from about 14 cm to about 30 cm, from about 14 cm to about 20 cm, from about 16 cm to about 20 cm, from about 18 cm to about 20 cm, or any range or subrange therebetween.
In aspects, the foldable apparatus can resist failure for a pen drop in a region (e.g., central portion 281) comprising the polymer-based portion 241 between the first portion 221 and the second portion 231 at a pen drop height of 1 cm, 2 cm, 3 cm, 4 cm, 5 cm, or more. In aspects, a maximum pen drop height that the foldable apparatus can withstand without failure over a region comprising the polymer-based portion 241 between the first portion 221 and the second portion 231 may be about 1 cm or more, about 2 cm or more, about 3 cm or more, about 4 cm or more, about 20 cm or less, about 10 cm or less, about 8 cm or less, or about 6 cm or less. In aspects, a maximum pen drop height that the foldable apparatus can withstand without failure over a region comprising the polymer-based portion 241 between the first portion 221 and the second portion 231 can be in a range from about 1 cm to about 20 cm, from about 2 cm to about 20 cm, from about 2 cm to about 10 cm, from about 3 cm to about 10 cm, from about 3 cm to about 8 cm, from about 4 cm to about 8 cm, from about 4 cm to about 6 cm, or any range or subrange therebetween. In aspects, a maximum pen drop height that the foldable apparatus can withstand without failure of a region comprising the polymer-based portion 241 between the first portion 221 and the second portion 231 can be in a range from about 1 cm to about 10 cm, from about 1 cm to about 8 cm, from about 1 cm to about 5 cm, from about 2 cm to about 5 cm, from about 3 cm to about 5 cm, from about 4 cm to about 5 cm, or any range or subrange therebetween.
Aspects of methods of making the foldable apparatus and/or foldable substrate in accordance with aspects of the disclosure will be discussed with reference to the flow chart in
After step 1301, as shown in
In aspects, as shown in
In further aspects, as shown by comparing
In further aspects, as shown by comparing
In aspects, as shown in
In aspects, after step 1301 or 1303, as shown in
After step 1301 or 1305, as shown in
After step 1307, as shown by comparing
After step 1309, as shown by comparing
After step 1311, as shown in
In aspects, the first barrier layer 2401 and/or the second barrier layer 2403 can reduce the diffusion of alkali metal ions therethrough during chemical strengthening in step 1315 (discussed below). In further aspects, the first barrier layer 2401 and/or the second barrier layer 2403 can prevent the diffusion of alkali metal ions therethrough during chemical strengthening in step 1315 (discussed below). In further aspects, the first barrier layer 2401 and/or the second barrier layer 2403 can comprise a covalent solid, as compared with an ionic solid. Without wishing to be bound by theory, a covalent solid can reduce (e.g., prevent, block) the diffusion of alkali metal ions therethrough. In further aspects, the first barrier layer 2401 and/or the second barrier layer 2403 can comprise one aluminum nitride (AlN), aluminum oxynitride (AlON, as described above), sputtered silicon nitride (Si3N4), or combinations thereof. In aspects, the second barrier layer 2403 can comprise the same material as the first barrier layer 2401. In aspects, disposing the first barrier layer 2401 and/or the second barrier layer 2403 can comprise sputtering, chemical vapor deposition, thermal evaporation, or electron-beam deposition. An exemplary aspect of disposing the first barrier layer 2401 and/or the second barrier layer 2403 comprises sputtering. In aspects, as shown in
Without wishing to be bound by theory, an increased density of a barrier layer can further reduce the diffusion of alkali metal ions therethrough. Without wishing to be bound by theory, an increased density of a barrier layer can correspond to a greater index of refraction relative to a lower density barrier layer of the same composition. In aspects, a refractive index of the first barrier layer and/or the second barrier layer can be about 1.5 or more, about 1.6 or more, about 1.7 or more, about 1.8 or more, about 2.1 or more, about 2.5 or less, about 2.3 or less, about 2.2 or less, about 2.1 or less, about 2 or less, or about 1.9 or less. In aspects, a refractive index of the first barrier layer and/or the second barrier layer can be in a range from about 1.5 to about 2.5, from about 1.6 to about 2.5, from about 1.6 to about 2.3, from about 1.7 to about 2.2, from about 1.7 to about 2.1, from about 1.7 to about 2, from about 1.7 to about 1.9, or any range or subrange therebetween. In aspects, a refractive index of the first barrier layer and/or the second barrier layer can be in range from about 1.7 to about 2.5, from about 1.8 to about 2.5, from about 2.1 to about 2.5, from about 2.1 to about 2.3, from about 2.2 to about 2.3, or any range or subrange therebetween.
In aspects, as shown in
In further aspects, as shown between
Although not shown in
After step 1309, 1311, or 1313, as shown in
In aspects, chemically strengthening the foldable substrate 201 in step 1315 can comprise chemically strengthening the first portion 221 comprising at least a portion of the first surface area 223 to form a first compressive stress region extending to a first depth of compression from the first surface area 223. In further aspects, chemically strengthening the foldable substrate 201 in step 1315 can comprise chemically strengthening the second portion 231 comprising at least a portion of the third surface area 233 to form a third compressive stress region extending to a third depth of compression from the first surface area 223. In aspects, chemically strengthening the foldable substrate 201 in step 1315 can comprise chemically strengthening the first portion 221 comprising at least a portion of the second surface area 225 to form a second compressive stress region extending to a second depth of compression from the second surface area 225. In aspects, chemically strengthening the foldable substrate 201 in step 1315 can comprise chemically strengthening the second portion 231 comprising at least a portion of the fourth surface area 235 to form a second compressive stress region extending to a second depth of compression from the fourth surface area 235. Without wishing to be bound by theory, chemically strengthening the foldable substrate 1405 without performing at least steps 1307 and 1309 can result in mechanical instabilities at least due to the lack of symmetry of the central region 248 of the central portion 281.
In aspects, the first depth of compression, second depth of compression, third depth of compression, and/or the fourth depth of compression, as a percentage of the substrate thickness 207 (see
In aspects, at the end of step 1315, the first compressive stress region can extend for less than the entire first surface area 223, for example, because the first barrier layer 2401 covers a portion of the first surface area 223 (see
After step 1315, as shown in
After step 1317, as shown in
In aspects, as shown in
After step 1315, 1317, or 1319, as shown in
In further aspects, as shown in
In aspects, methods of making a foldable apparatus in accordance with aspects of the disclosure can proceed along steps 1301, 1303, 1305, 1307, 1309, 1311, 1313, 1315, 1317, 1319, 1321, and 1323 of the flow chart in FIG. 13 sequentially, as discussed above. In aspects, arrow 1302 can be followed from step 1301 to step 1305, for example, when the foldable substrate 1405 already comprises the recess 219. In aspects, arrow 1304 can be followed from step 1301 to step 1307, for example, when the foldable substrate 1405 already comprises a laminate with the recess 219. In aspects, arrow 1308 can be followed from step 1309 to step 1315, for example, when the support layers comprise the same material as the barrier layers. In aspects, arrow 1310 can be followed from step 1311 to step 1315, for example, when the central portion 281 of the foldable substrate 201 to be chemically strengthened in step 1315. In aspects, arrow 1312 can be followed from step 1315 to step 1321, for example, when the foldable substrate 201 is not to be further chemically strengthened during the method. In aspects, arrow 1314 can be followed from step 1317 to step 1321, for example, when the foldable substrate 201 is not further chemically strengthened. In aspects, arrow 1306 can be followed from step 1311 to step 1323, for example, when the foldable substrate 201 is complete after step 1311. In aspects, arrow 1318 can be followed from step 1315 to step 1323, for example, when the method is complete after the foldable substrate 201 is chemically strengthened in step 1315. For example, the barrier layers may be part of a larger device that the foldable substrate is to be incorporated into, the barrier layers may be useful for subsequent processing (e.g., in another method), and/or for storage of the foldable substrate prior to subsequent processing (e.g., in another method). In aspects, arrow 1316 can be followed from step 1317 to step 1323, for example, when the method is complete after removing the barrier layers in step 1317. In aspects, arrow 1320 can be followed from step 1319 to step 1323, for example, when the method is complete after the further chemically strengthening the foldable substrate 201 in step 1319. Any of the above options may be combined to make a foldable apparatus in accordance with aspects of the disclosure.
Various aspects will be further clarified by the following examples. Examples A-H and AA comprise a glass-based substrate (Composition 1 having a nominal composition in mol % of: 63.6 SiO2; 15.7 Al2O3; 10.8 Na2O; 6.2 Li2O; 1.16 ZnO; 0.04 SnO2; and 2.5 P2O5) with a substrate thickness 207 of 100 μm, a central thickness 217 of 30 μm, a width 282 of the central portion 281 of 20 mm, and the transition between the central region and the first portion or second portion comprised a width of about 100 μm. Examples A-H were processed following the methods described above with the barrier layers (e.g., first barrier layer 2401 and second barrier layer 2403 shown in
Table 1 presents the durability of barrier layer through the chemical strengthening in step 1315 and removal in step 1317. Ideally, the barrier layer serves as a barrier to ions from the salt bath and does not crack or dissolve during step 1317, but the barrier layer can easily be removed in step 1317 with an etching solution. For Example A-H and AA, step 1315 comprised immersing the foldable substrate in a salt bath consisting of 100 wt % KNO3 maintained at 390° C. for 30 minutes. As shown in Table 1, Example D (SiC) cracked due to thermal shock when placed in the salt bath. Example E (Al2O3) was at least partially dissolved in the salt bath. Examples A-C survived the chemical strengthening of step 1315 without problems. However, Example C (SiAlON) was hard to remove using the etching solution without damaging a surface of the foldable substrate. Examples A-B (AlN and AlON) were removed using the etching solution without damaging the foldable substrate.
As shown in Table 2, the barrier layer of Examples F—H comprise AlON while Example AA is a comparative example. In Table 2, “compressive stress” refers to the maximum compressive stress of the first central surface area measured using the FSM-6000 after the barrier layer is removed at the end of step 1317 while the “depth of layer” is determined from using the SCALP-5 at the end of step 1317. Examples F-G were able to prevent diffusion of the ions in the salt bath such that no compressive stress nor depth of layer was detectable. In contrast, Example H cracked due to thermal shock upon being placed in the salt bath. Consequently, providing a thickness of an AlON barrier layer of less than 300 nm can prevent cracking due to thermal shock. Example AA comprised a compressive stress of 1,000 MPa and a depth of layer of 10.2 μm. Comparing Examples F-G with Example AA, 100% of the compressive stress and depth of layer was prevented by the AlON, which had a barrier thickness as low as 38 nm in Example F. Examples F-G were tested in the parallel plate apparatus to a parallel plate distance of 3 mm. Examples F-G were able to obtain the parallel plate distance of 3 mm without encountering any mechanical instabilities.
The above observations can be combined to provide foldable substrates, foldable apparatus comprising foldable substrates, and methods of making foldable substrates that comprise a first portion and a second portion and foldable apparatus comprising foldable substrates. The portions can comprise glass-based and/or ceramic-based portions, which can provide good dimensional stability, reduced incidence of mechanical instabilities, good impact resistance, and/or good puncture resistance. The first portion and/or the second portion can comprise glass-based and/or ceramic-based portions comprising one or more compressive stress regions, which can further provide increased impact resistance and/or increased puncture resistance. By providing a substrate comprising a glass-based and/or ceramic-based substrate, the substrate can also provide increased impact resistance and/or puncture resistance while simultaneously facilitating good folding performance. In aspects, the substrate thickness can be sufficiently large (e.g., from about 80 micrometers (microns or μm) to about 2 millimeters) to further enhance impact resistance and puncture resistance. Providing foldable substrates comprising a central portion comprising a central thickness that is less than a substrate thickness can enable a small parallel plate distance (e.g., about 10 millimeters or less) based on the reduced thickness in the central portion.
In aspects, the foldable apparatus and/or foldable substrates can comprise a recess, for example, a first central surface area recessed from a first major surface by a first distance. Providing a recess can increase bendability of the foldable apparatus since the central thickness can be less than the substrate thickness. Additionally, controlling properties of a material positioned in the recess can control the position of a neutral axis of the foldable apparatus and/or foldable substrates, which can reduce (e.g., mitigate, eliminate) the incidence of mechanical instabilities, apparatus fatigue, and/or apparatus failure.
Providing a blunted edge between the first major surface and the second major surface and/or between the first central surface area and the second major surface can increase an impact resistance and/or decrease an incidence of failure of the foldable substrate. Providing the blunted edge extending around an entire periphery of the foldable substrate can further increase an impact resistance and/or decrease an incidence of failure of the foldable substrate. Further, providing the blunted edge comprising the first blunted surface area, the second blunted surface area, and the central blunted surface area can reduce and/or avoid mechanical instabilities. For example, the foldable substrate can be symmetric about a first plane extending in a direction of the central thickness and along a midline between the first portion and the second portion, and/or the foldable substrate can be symmetric about a second plane extending in the direction of the central thickness and perpendicular to the first plane. Providing a central region of the central portion that can be symmetric about a third plane extending parallel to the first central surface area and the second central surface area at a midpoint therebetween. Since mechanical instabilities can develop from an asymmetry in a region of the foldable substrate as a region where stress and/or strain concentrates, providing the central region symmetric about the first plane, the second plane, and/or the third plane can reduce the incidence of mechanical instabilities. Since the regions comprising the smallest thickness are the most susceptible to mechanical instabilities (e.g., lower critical buckling strain, less stress required to reach a critical buckling strain), reducing the chance of mechanical instabilities in the central region comprising the central thickness reduces the incidence of mechanical instabilities for the foldable substrate overall.
Providing the foldable substrate with a central portion that can be substantially unstrengthened can reduce an incidence of mechanical instabilities. For example, the unstrengthened central portion can result in a chemical strengthening induced expansion strain profile of the foldable substrate measured from a midline of the central portion that monotonically increase, which can reduce an incidence of mechanical instabilities. Similarly, a profile of absolute values of the maximum tensile stress or the maximum compressive stress of the foldable substrate measured from a midline of the central portion can monotonically increase. Alternatively, providing a central portion comprising a depth of compression and/or depth of layer as a percentage of the central thickness that is less than or equal to the corresponding depth of the first portion as a percentage of the substrate thickness can reduce an incidence of mechanical instabilities while increasing the puncture resistance of the entire foldable substrate.
Method aspects of the disclosure can reduce an incidence of mechanical instabilities while increasing an impact resistance and/or increase a puncture resistance of the foldable apparatus. For example, methods can produce the blunted edge described above that includes the central blunted surface area. Using the method of aspects of the disclosure comprising etching the foldable substrate after removing an initial edge can produce an edge surface with minimal surface flaws (e.g., preexisting or generated during prior processing) since surface flaws can be treated (e.g., blunted, removed, reduced) during the etching. By forming the edge surface before chemically strengthening the foldable substrate, mechanical instabilities of the foldable substrate can be avoided during processing as well as in the final foldable substrate. Providing the first barrier layer and the second barrier layer over the central portion can reduce mechanical instabilities by establishing the chemical strengthening induced expansion strain profile, maximum tensile stress profile, and/or compressive stress profile described above, which can reduce an incidence of mechanical instabilities. Providing a barrier layer comprising a covalent solid can minimize an amount of material needed to achieve one of the above-mentioned profiles. Providing a barrier layer comprising aluminum nitride, aluminum oxynitride, and/or sputtered silicon nitride can achieve one of the above-mentioned profiles while being removable without damaging the foldable substrate.
Directional terms as used herein—for example, up, down, right, left, front, back, top, bottom—are made only with reference to the figures as drawn and are not intended to imply absolute orientation.
It will be appreciated that the various disclosed aspects may involve features, elements, or steps that are described in connection with that aspect. It will also be appreciated that a feature, element, or step, although described in relation to one aspect, may be interchanged or combined with alternate aspects in various non-illustrated combinations or permutations.
It is also to be understood that, as used herein the terms “the,” “a,” or “an,” mean “at least one,” and should not be limited to “only one” unless explicitly indicated to the contrary. For example, reference to “a component” comprises aspects having two or more such components unless the context clearly indicates otherwise. Likewise, a “plurality” is intended to denote “more than one.”
As used herein, the term “about” means that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and/or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art. Ranges can be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, aspects include from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. Whether or not a numerical value or endpoint of a range in the specification recites “about,” the numerical value or endpoint of a range is intended to include two aspects: one modified by “about,” and one not modified by “about.” It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint and independently of the other endpoint.
The terms “substantial,” “substantially,” and variations thereof as used herein are intended to note that a described feature is equal or approximately equal to a value or description. For example, a “substantially planar” surface is intended to denote a surface that is planar or approximately planar. Moreover, as defined above, “substantially similar” is intended to denote that two values are equal or approximately equal. In aspects, “substantially similar” may denote values within about 10% of each other, for example, within about 5% of each other, or within about 2% of each other.
Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that any particular order be inferred.
While various features, elements or steps of particular aspects may be disclosed using the transitional phrase “comprising,” it is to be understood that alternative aspects, including those that may be described using the transitional phrases “consisting of” or “consisting essentially of,” are implied. Thus, for example, implied alternative aspects to an apparatus that comprises A+B+C include aspects where an apparatus consists of A+B+C and aspects where an apparatus consists essentially of A+B+C. As used herein, the terms “comprising” and “including”, and variations thereof shall be construed as synonymous and open-ended unless otherwise indicated.
The above aspects, and the features of those aspects, are exemplary and can be provided alone or in any combination with any one or more features of other aspects provided herein without departing from the scope of the disclosure.
It will be apparent to those skilled in the art that various modifications and variations can be made to the present disclosure without departing from the spirit and scope of the disclosure. Thus, it is intended that the present disclosure cover the modifications and variations of the aspects herein provided they come within the scope of the appended claims and their equivalents.
This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application Ser. No. 63/275,053 filed on Nov. 3, 2021, the content of which is relied upon and incorporated herein by reference in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2022/047827 | 10/26/2022 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63275053 | Nov 2021 | US |
