The disclosure relates generally to sealed electronic device housing and specifically to hermetically sealed, glass structures for electronic devices, such as organic LEDs (OLEDs). In general, hermetic sealing of OLED displays is needed to provide barriers against materials, such as water and oxygen. Typically, frit sealing is used to adhesively bond together two substrates around each OLED cell in an OLED display.
One embodiment of the disclosure relates to a laser-welded, sealed electronic device housing. The housing includes a first substrate having a first surface and a second substrate having a second surface facing the first surface. The housing includes a recess formed in the first substrate, and the recess faces the second surface such that the second surface and the recess define a chamber. The housing includes a laser weld bonding the first surface to the second surface, and the laser weld surrounds the chamber. The housing includes a functional film supported by at least one of the first surface and the second surface, and the functional film extends from the chamber and across the laser weld.
An additional embodiment of the disclosure relates to a sealed electronic device. The device includes a first glass substrate having a first surface and a second glass substrate having a second surface facing the first surface. The device includes a chamber defined between the first surface and the second surface. The device includes a hermetic seal surrounding the chamber, and the seal is formed from a portion of the first substrate joined together with a portion of the second substrate. The device includes a functional film forming extending from the chamber and across the seal.
An additional embodiment of the disclosure relates to a method of forming a sealed electronic device housing. The method includes providing a first substrate having a first surface. The method includes providing a second substrate having a second surface. The method includes forming a recess in the first surface of the first substrate. The method includes placing the first substrate adjacent to the second substrate such that first surface faces the second surface and the recess forms a chamber with an opposing portion of the second surface of the second substrate. The method includes providing a functional film on at least one of the first surface and the second surface. The method includes forming a weld between the first surface and the second surface using a laser, wherein the weld surrounds the chamber and traverses the functional film, and the functional film extends from the chamber across the weld.
Additional features and advantages will be set forth in the detailed description that follows, and, in part, will be readily apparent to those skilled in the art from the description or recognized by practicing the embodiments as described in the written description and claims hereof, as well as the appended drawings.
It is to be understood that both the foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework to understand the nature and character of the claims.
The accompanying drawings are included to provide a further understanding and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiment(s), and together with the description serve to explain principles and the operation of the various embodiments.
Referring generally to the figures, various embodiments of a sealed electronic device, such as a sealed OLED device, are shown and described. In general, the sealed electronic device discussed herein includes two opposing substrates (e.g., glass sheet substrates) with a recess or chamber formed between the two substrates, and an active component, such as an OLED, located within the chamber. A weld surrounds the chamber hermetically sealing the active component within the chamber. In specific embodiments, the weld is a laser weld formed by portions of the first and second substrates that are joined or melted together using a laser. Thus, in general the laser welds discussed herein are cohesive structures which form a strong and hermetic seal around the chamber. In various embodiments, a functional film is located on at least one of the substrates and forms a path extending from the chamber and across the laser weld, and in specific embodiments, the functional film is a conductive material forming first and second electrically conductive leads extending across the laser weld providing electrical conduction to the active component located with the chamber. As will be understood, sealing of conventional electronic devices that utilize frit-based sealing is based on adhesive bonding between the frit and the adjacent substrate materials. In contrast to the conventional frit sealed devices, the laser-welded electronic devices discussed herein provides cohesive laser welds having low thickness and high weld strength as compared to frit sealed devices.
Referring to
At least one of substrates 12 and 14 includes a recess formed in the material of the substrate. In the embodiment shown, a recess 20 is formed in upper substrate 14. When upper substrate 14 is located on lower substrate 12, as shown in
In various embodiments, OLED device 10 may be used in a variety of applications such as electronic displays, and may be used in small displays such as mobile device displays or large displays such as TV displays, monitors, etc. In various embodiments, the active component may be any electronic component, including various semi-conductor devices, including photovoltaic devices. In various embodiments, the hermetic encapsulation of an active component using the materials and methods disclosed here can facilitate long-lived operation of devices otherwise sensitive to degradation by oxygen and/or moisture. In exemplary embodiments, device 10 includes flexible, rigid or semi-rigid organic LEDs, OLED lighting, OLED televisions, MEMs displays, electrochromic windows, fluorophores, alkali metal electrodes, transparent conducting oxides, quantum dots, etc.
Device 10 includes a hermetic seal, shown as laser weld 26 surrounding chamber 22. In general, laser weld 26 bonds together substrates 12 and 14 coupling the substrates relative to each other and hermetically sealing OLED 24 within chamber 22. In one embodiment, laser weld 26 is a closed perimeter seal formed between substrates 12 and 14.
As will be understood, frit sealed electronic devices include a bead of frit that is melted between opposing substrates such that adhesive bonds are formed between the frit and both of the opposing substrates, and in this type of arrangement, the frit material adhesively bonded between the substrates act to form the hermetic seal around the OLED. In contrast to frit sealed devices, laser weld 26 is a cohesive structure formed from opposing portions of substrates 12 and 14 that are joined together, such as by melting. It is believed that the cohesive weld structure of laser weld 26 provides stronger bonding with a lower overall thickness as compared to the adhesive-based bonding structure of a frit sealed electronic device. It should be understood that as used herein joining together of substrates includes a weld formed by one or both of the substrates attaining viscoelastic flow from increased temperatures (e.g., laser induced temperatures) and being thermo-compressed together, a diffusion weld and/or a weld formed where the melting point of the substrates is exceeded. In various embodiments, within laser weld 26, the fictive temperature of the material of substrates 12 and 14 is changed relative to the fictive temperature of the material of substrates 12 and 14 outside of laser weld 26. In specific embodiments, within laser weld 26, the fictive temperature of the material of substrates 12 and 14 is greater than the fictive temperature of the material of substrates 12 and 14 outside of laser weld 26. In one embodiment, laser weld 26 can be reinforced with a perimeter seal surrounding OLED 24.
Device 10 includes at least one functional film material supported by at least one of substrates 12 and 14 and that forms a path extending from within chamber 22 and across laser weld 26. In the embodiment shown in
In various embodiments, laser weld 26 may be formed in a variety of suitable ways in which the materials of substrates 12 and 14 are melted together through the use of laser energy shown schematically in
In various embodiments, laser weld 26, leads 30 and 32, and laser absorbing film 38 are sized and structured to facilitate formation of a low-thickness, hermetically sealed electronic device. As shown in
Referring to
In various embodiments, the relative sizes of leads 30 and 32, chamber 22 and laser weld 26 facilitate formation of device 10 having a low total thickness. For example, in one embodiment, T2 is less than 20% of H1. In another embodiment, T1 is less than 20% of H2. In a specific embodiment, both T1 and T2 are less than 20% of H1. In such embodiments, thicknesses or heights of the components discussed herein are the dimensions of the components measured in a direction perpendicular to the major surfaces of the substrates. In some embodiments, the widths, thicknesses and heights discussed herein represent maximum measured dimensions, and in other embodiments, the widths, thicknesses and heights discussed herein represent average measured dimensions. In various embodiments, the width of laser weld 26 is larger than absorbing film 38 thickness. For example, the width and/or thickness of the portion of the substrates that have a change in glass fictive temperature around laser weld 26 is greater than the thickness of absorbing film 38. In various embodiments, the width and/or thickness of of the entire weld region (including the residual stress portion) exceeds the thickness of the absorbing film 38. A survey of the local density distribution, or fictive temperature distribution, in the vicinity of the weld can be used to determine this relative dimensions.
As noted above, in various embodiments, because laser 34 forms laser weld 26 over and around leads 30 and 32, leads 30 and 32 are structured to maintain a satisfactory level of conductivity following formation of laser weld 26. In particular, leads 30 and 32 are structured such that the temperature needed to cause the melting of the materials of substrates 12 and 14 does not eliminate or significantly reduce the conductivity of leads 30 and 32. In various exemplary embodiments, leads 30 and 32 are formed from a material having a melting temperature that is greater than the melting temperature of the material of substrates 12 and 14. In various embodiments, leads 30 and 32 are formed from a material having a melting temperature that is at least 10% greater than the melting point temperature and/or the softening point temperature of the material of substrates 12 and 14. In a specific embodiment, leads 30 and 32 are formed from a material having a melting temperature that is greater than 700 degrees C., and in another embodiment, leads 30 and 32 are formed from a material having a melting temperature that is greater than 800 degrees C. In a specific embodiment, leads 30 and 32 are formed from a material having a melting temperature that is between 800 degrees C. and 900 degrees C. In such embodiments, substrates 12 and 14 may be made from a soda-lime glass material having a softening point of about 700 degrees C., and in other embodiments, substrates 12 and 14 may be made from Eagle XG® glass sheet material available from Corning, Inc. which has a softening point of about 970 degrees C. In various embodiments, leads 30 and 32 are made from a material that experiences an increase in resistivity following formation of laser weld 26 that is less than 30%.
In various embodiments, leads 30 and 32 may be formed from any suitable conductive material. In specific embodiments, leads 30 and 32 are formed from at least one of indium tin oxide (ITO), molybdenum, silver, or copper. In various embodiments, laser absorbing film 38 is formed from any material suitable for absorbing laser energy to facilitate melting of substrates 12 and 14 to form laser weld 26. In various embodiments, laser absorbing film 38 is a material that absorbs any suitable wavelength of laser energy including ultraviolet spectrum laser energy, infrared spectrum laser energy, near infrared spectrum laser energy and visible spectrum laser energy. In specific embodiments, laser absorbing film 38 is a material that absorbs in the 200-410 nm wavelength range, and in other embodiments, laser absorbing film 38 is a material that absorbs in the 800-1900 nm wavelength range.
In specific embodiments, laser absorbing film 38 is formed from at least one of a low melting glass (LMG) having a Tg less than 600 degrees C., ZnO, SnO, TiO2, Nb2O5, and a glass film doped with a transition metal, such as Fe, Mn, Cu, Va, Cr. In some embodiments, laser absorbing film 38 is absorbing at a non-visible spectrum of laser 34 while being transparent/translucent to visible light. In a specific embodiment, the laser absorbing film and substrates 12 and 14 are transparent to light within a wavelength range of 420 nm to 750 nm. In some other embodiments, laser absorbing film 38 is absorbing at a non-visible spectrum of laser 34 while being opaque to visible light.
It should be understood that while most of the embodiments discussed herein discuss formation of a device having a functional film material that acts as leads for an active device such as OLED 24, in other embodiments, device 10 may include other functional films. For example, in one embodiment, the functional film traversing laser weld 26 may be a protective film material, such as an SiN film. Further, it should be understood that while
Referring to
As shown in
As shown in
As will be understood, in embodiments in which a laser absorbing film 38 is used, laser 34 has a wavelength selected to interact with the particular laser absorbing film. As noted above, laser 34 may be a UV, IR or visible light laser, and laser absorbing film 38 is selected to absorb within the wavelength of laser 34. In addition, various aspects of laser 34 may be controlled to facilitate formation of laser weld 36 while maintaining the functionality of leads 30 and 32. In various embodiments, the power and scanning speed of laser 34 may be controlled during formation of laser weld 26. For example in some embodiments, laser 34 is a 355 nm laser with a power between 0.1 W and 1.0 W, and specifically, 0.1 W and 0.5 W. In a specific embodiment, laser 34 is a 355 nm laser with a power of 0.6 W and a scanning speed of between 10 mm/s and 50 mm/s, and specifically of 25 mm/s, and laser absorbing film 38 is LMG film coating. In such embodiments, the LMG film coating 38 has a thickness of 1 μm, and leads 30 and 32 are ITO leads that have a thickness of 150 nm. In other embodiments, laser 34 may be a laser, such as a short pulse laser, capable of forming laser weld 26 without the absorbing film. In various specific embodiments, the lasers, processes and materials may be any of those disclosed in U.S. Publication No. 2015/0027168 (U.S. application Ser. No. 14/271,797, filed May 7, 2014), which is incorporated herein by reference in its entirety.
As used herein, a hermetic seal and/or hermetically sealed device is one which, for practical purposes, is considered substantially airtight and substantially impervious to moisture and/or oxygen. By way of example, laser weld 26 can be configured to limit the transpiration (diffusion) of oxygen to less than about 10−2 cm3/m2/day (e.g., less than about 10−3 cm3/m2/day), and limit the transpiration (diffusion) of water to about 10−2 g/m2/day (e.g., less than about 10−3, 10−4, 10−5 or 10−6 g/m2/day). In such embodiments, the hermetic seal substantially inhibits air and water from contacting a protected active element, such as OLED 24.
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 in no way intended that any particular order be inferred. In addition, as used herein, the article “a” is intended to include one or more than one component or element, and is not intended to be construed as meaning only one.
It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the disclosed embodiments. Since modifications, combinations, sub-combinations and variations of the disclosed embodiments incorporating the spirit and substance of the embodiments may occur to persons skilled in the art, the disclosed embodiments should be construed to include everything 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. 62/208,900, filed on Aug. 24, 2015, the content of which is relied upon and incorporated herein by reference in its entirety.
Filing Document | Filing Date | Country | Kind |
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PCT/US16/48103 | 8/23/2016 | WO | 00 |
Number | Date | Country | |
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62208900 | Aug 2015 | US |