Patent Application
20230071917
This application claims the benefit of Korean Patent Application No. 10-2021-0117570 filed on Sep. 3, 2021, in the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference for all purposes.
One or more example embodiments relate to an encapsulated organic light emitting device and a method for fabrication thereof.
An organic light emitting device is formed on an anode formed on a flexible or rigid substrate, and includes a hole transport layer that injects holes into an organic light emitting layer, the organic light emitting layer formed on the hole transport layer, an electron injection layer formed on the organic light emitting layer to inject electrons into the organic light emitting layer, and a cathode connected to the electron injection layer.
The organic light emitting device has excellent characteristics such as a wide viewing angle, high speed response, high contrast, high luminous efficiency, and no need for a separate light source.
The related art described above is possessed or acquired by the inventor in the process of deriving the disclosure of the present application, and is not necessarily known art published to the general public prior to the present application.
The organic light emitting device is very vulnerable to moisture and oxygen, and when electrode materials of the organic light emitting device are oxidized and its characteristics deteriorate, the lifespan of the organic light emitting device is rapidly reduced. Accordingly, in order to secure stability and reliability of the organic light emitting device, it may be required to develop a technology capable of efficiently blocking penetration of moisture and oxygen into the organic light emitting device.
However, the technical tasks are not limited to the above-described technical tasks, and other technical tasks may exist.
According to an aspect, there is provided an encapsulated organic light emitting device including a plurality of organic light emitting devices formed on a substrate, a partition wall disposed to separate the plurality of organic light emitting devices, a hydrophobic oil filling a housing structure defined by the partition wall, a polymer thin film formed on surfaces of the hydrophobic oil and the partition wall using a photo-curable precursor, and a multi-film laminated on the polymer thin film.
The height of the partition wall may be 0.5 µm to 5 µm, and the partition wall may be a trapezoidal pixel defining layer (PDL) with a lower portion wider than an upper portion.
The hydrophobic oil may have a refractive index of 1.29 to 1.6, a contact angle with water of 90 degrees or more, and a specific gravity of 1.2 or more, and may be one of fluorine oil, siloxane oil, paraffin oil, amorphous fluorine-based oil, silicone oil, mineral oil, almond oil, corn oil, cottonseed oil, linseed oil, tung oil, castor oil, cinnamin oil, and coconut oil. The fluorine oil may include an amorphous fluoropolymer, the siloxane oil may include polyphenyl-methyl siloxane, polydiphenyl siloxane, and polydimethyl siloxane, and the amorphous fluorine-based oil may include tetrafluoroethylene, trifluoroethylene, difluoroethylene, 2,2-bisfluoromethyl-4,5-difluoro-1,3-dixole, and chlorotrifluoroethylene.
The polymer thin film may have a thickness of 1 µm or less, and may be formed by coating the photo-curable precursor on the surfaces of the hydrophobic oil and the partition wall followed by a curing reaction or by filling the housing structure with a liquid in which the photo-curable precursor is mixed with the hydrophobic oil followed by a curing reaction of a phase-separated photo-curable precursor.
The photo-curable precursor may be a mixture in which one or more of a reactive precursor, a photoinitiator, and an additive are combined.
The reactive precursor may have a specific gravity of 1.0 to 1.2 and may have less miscibility and specific gravity than the hydrophobic oil, and the reactive precursor may include one or more of 1,6-hexandiol diacrylate (HAD), 2-hydroxyethyl methacrylate (2-HEMA), 2-ethylheeth acrylate, hydroxyethyl acrylate (HEA), methyl methacrylate (MMA), methacrylate (MA), isobornyl acrylate (IOBA), 2-(2-ethoxyethoxy) ethyl acrylate (EOEOEA), triethylopropane triacrylate (TMPTA), trimethylolpropane dially ether (TMPDE), tri(propylene glycol) diacrylate (TPGDA), pentaerythritol triacrylate (PETA), ethylene glycol dimethacrylate (EGDA), triethylopropane trimethacrylate (TMPTMA), 2-phenoxyethyl acrylate (2-PEA), trimethylolpropane ethoxylate triacrylate (TMPEOTA), tetrahydrofurfuryl acrylate (THFA), and urethane diacrylate.
The photoinitiator may have a weight of 0.1% to 10% of the polymer thin film and may be a mixture of two or more UV curing agents.
The curing reaction may use ultraviolet rays having a wavelength in a range of 300 nm to 400 nm, and use photocuring energy of 20 mJ to 2000 mJ.
The multi-film is formed by laminating an encapsulation layer on an adhesive sheet including one of a double-sided adhesive made using a double-sided adhesive film and the double-sided adhesive film, and the encapsulation layer may be one of an encapsulation film which is a film in which plastic and inorganic material are laminated or a multilayer film formed by laminating only the inorganic material, and a glass substrate.
The double-sided adhesive film may be coated with an adhesive layer including only one polymer of acrylate and epoxy-based polymers, and the double-sided adhesive may be formed by repeating a structure in which the adhesive layer, a support for supporting the adhesive layer, and the adhesive layer are laminated.
The encapsulated organic light emitting device may further include a moisture absorption layer for absorbing moisture and oxygen in the atmosphere between the encapsulation layer and the adhesive sheet or a moisture absorbent may be added to the double-sided adhesive.
According to an aspect, there is provided a fabrication method of fabricating an encapsulated organic light emitting device including forming a plurality of organic light emitting devices on a substrate, forming a partition wall disposed to separate the plurality of organic light emitting devices, filling a housing structure defined by the partition wall with a hydrophobic oil, forming a polymer thin film on surfaces of the hydrophobic oil and the partition wall using a photo-curable precursor, and laminating a multi-film on the polymer thin film.
The height of the partition wall may be 0.5 µm to 5 µm, and the partition wall may be a trapezoidal PDL with a lower portion wider than an upper portion.
The hydrophobic oil may have a refractive index of 1.29 to 1.6, a contact angle with water of 90 degrees or more, and a specific gravity of 1.2 or more.
The polymer thin film may have a thickness of 1 µm or less, and may be formed by coating the photo-curable precursor on the surfaces of the hydrophobic oil and the partition wall followed by a curing reaction or by filling the housing structure with a liquid in which the photo-curable precursor is mixed with the hydrophobic oil followed by a curing reaction of a phase-separated photo-curable precursor.
The photo-curable precursor may be a mixture in which one or more of a reactive precursor, a photoinitiator, and an additive are combined, the reactive precursor may have a specific gravity of 1.0 to 1.2 and may have less miscibility and specific gravity than the hydrophobic oil, and the photoinitiator may have a weight of 0.1% to 10% of the polymer thin film and may be a mixture of two or more UV curing agents.
The multi-film may be formed by laminating one of a double-sided adhesive made using a double-sided adhesive film and the double-sided adhesive film and an encapsulation layer, and the encapsulation layer may be one of an encapsulation film and a glass substrate.
The the double-sided adhesive film may be coated with an adhesive layer including only one polymer of acrylate and epoxy-based polymers, and the double-sided adhesive may be formed by repeating a structure in which the adhesive layer, a support for supporting the adhesive layer, and the adhesive layer are laminated.
The encapsulated organic light emitting device may further include a moisture absorption layer for absorbing moisture and oxygen in the atmosphere between the encapsulation layer and the adhesive sheet or a moisture absorbent may be added to the double-sided adhesive.
According to another aspect, there is provided a display including an encapsulated organic light emitting device and a thin film transistor (TFT) inserted between a substrate of the encapsulated organic light emitting device and an organic light emitting device. The encapsulated organic light emitting device may include a plurality of organic light emitting devices formed on the substrate, a partition wall disposed to separate the plurality of organic light emitting devices, a hydrophobic oil filling a housing structure defined by the partition wall, a polymer thin film formed on surfaces of the hydrophobic oil and the partition wall using a photo-curable precursor, and a multi-film laminated on the polymer thin film.
These and/or other aspects, features, and advantages of the invention will become apparent and more readily appreciated from the following description of example embodiments, taken in conjunction with the accompanying drawings of which:
Specific structural or functional descriptions of example embodiments are disclosed for purposes of illustration only, and may be changed and implemented in various forms. Accordingly, actual implementation is not limited to specific example embodiments disclosed, and the scope of the present specification includes changes, equivalents, or substitutes included in the technical spirit described as example embodiments.
Although terms such as first or second may be used to describe various elements, these terms should be interpreted merely for the purpose of distinguishing one element from another element. For example, a first element may be named a second element, and similarly, a second element may also be named a first element.
When an element is referred to as being “connected to” another element, it may be directly connected or joined to the other element, but it should be understood that another element may exist in between.
A singular expression includes a plural expression unless the context clearly dictates otherwise. In this specification, it should be understood that terms such as “comprise”, “include”, or “have” are intended to indicate that a described feature, number, step, operation, element, part, or combination thereof exists, and does not preclude in advance the possibility of addition or presence of one or more other features, numbers, steps, operations, elements, parts, or combinations thereof.
Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meanings as commonly understood by a person skilled in the art. Terms such as those defined in commonly used dictionaries should be interpreted as having meanings consistent with meanings in the context of the related art, and should not be interpreted in ideal or excessively formal meanings unless explicitly defined in the present specification.
Hereinafter, example embodiments will be described in detail with reference to the accompanying drawings. In descriptions with reference to the accompanying drawings, the same elements are indicated by the same reference numerals regardless of numerals in the drawings, and overlapping descriptions thereof will be omitted.
Referring to
Referring to
According to various example embodiments, a plurality of organic light emitting devices 200 may be formed on the substrate 122. The substrate 122 may be a flexible substrate made of one of plastic, thin glass, and metal foil. The partition wall 310 may have a PDL structure that divides a pixel boundary of the organic light emitting device 200 or another structure having substantially the same function as the PDL structure to separate each organic light emitting device 200 and may be disposed on the organic light emitting device 200. The partition wall 310 may be formed using a photosensitive high heat-resistant organic material and may have a trapezoidal shape with a lower portion wider than an upper portion, and the height of the partition wall 310 may be 0.5 µm to 5 µm.
According to various example embodiments, a housing structure defined by the partition wall 310 may be filled with the hydrophobic oil 320. The hydrophobic oil 320 may have excellent barrier properties against oxygen and moisture to be suitable for a barrier and heat-sink. The hydrophobic oil 320 may have a refractive index of 1.29 to 1.6, a contact angle with water of 90 degrees or more, and a specific gravity of 1.2 or more. For example, the hydrophobic oil 320 may be one of fluorine oil, siloxane oil, paraffin oil, amorphous fluorine-based oil, silicone oil, mineral oil, almond oil, corn oil, cottonseed oil, linseed oil, tung oil, castor oil, cinnamin oil, and coconut oil. The fluorine oil may include an amorphous fluoropolymer, the siloxane oil may include polyphenyl-methyl siloxane, polydiphenyl siloxane, and polydimethyl siloxane, and the amorphous fluorine-based oil may include tetrafluoroethylene, trifluoroethylene, difluoroethylene, 2,2-bisfluoromethyl-4,5-difluoro-1,3-dixole, and chl orotrifluoroethyl ene.
According to various example embodiments, the polymer thin film 400 may be formed using a photo-curable precursor on surfaces of the hydrophobic oil 320 and the partition wall 310 to fix the hydrophobic oil 320. The thickness of the polymer thin film 400 may be 1 µm or less.
According to various example embodiments, it is possible to prevent contamination from occurring due to movement of the hydrophobic oil 320 during an encapsulation process by the multi-film 500 and improve the reliability of the organic light emitting device 200, by forming the polymer thin film 400 on the surfaces of the hydrophobic oil 320 and the partition wall 310.
According to various example embodiments, the photo-curable precursor may be a mixture in which one or more of a reactive precursor, a photoinitiator, and an additive are combined. The reactive precursor may have a specific gravity of 1.0 to 1.2, and may have less miscibility and specific gravity than the hydrophobic oil 320. For example, the reactive precursors may include one or more of 1,6-hexandiol diacrylate (HAD), 2-hydroxyethyl methacrylate (2-HEMA), 2-ethylheeth acrylate, hydroxyethyl acrylate (HEA), methyl methacrylate (MMA), methacrylate (MA), isobornyl acrylate acrylate (IOBA), 2-(2-ethoxyethoxy) ethyl acrylate (EOEOEA), triethylopropane triacrylate (TMPTA), trimethylolpropane dially ether (TMPDE), tri(propylene glycol) diacrylate (TPGDA), pentaerythritol triacrylate (PETA), ethylene glycol dimethacrylate (EGDA), triethylopropane trimethacrylate (TMPTMA), 2-phenoxyethyl acrylate (2-PEA), trimethylolpropane ethoxylate triacrylate (TMPEOTA), tetrahydrofurfuryl acrylate (THFA), and urethane diacrylate.
According to various example embodiments, the photoinitiator may be 0.1% to 10% by weight of the polymer thin film 400 and may be a mixture of two or more UV curing agents to improve the curing rate during a curing reaction of the photo-curable precursor (for example, a photocuring reaction). For example, the UV curing agent may be one of Benzophenone, 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 907), JR Cure, 2-Methyl-1[4-(methylthio)phenyl]-2-morpholinopropane-1-one (Irgacure 184C), 1-Hydroxy-2-methyl-1-phenyl-propane-1-one (Darocur 1173), an initiator obtained by mixing 50 wt% of Irgacure 184C and 50 wt% of Benzophenone (Irgacure 500), an initiator obtained by mixing 20 wt% of Irgacure 184 and 80 wt% of Irgacure 1173 (Irgacure 1000), 2-Hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1 propanone (Irgacure 2959), Methylbenzoylformate (Darocur MBF), Alpha, alpha-dimethoxy-alpha-phenylacetophenone (Irgacure 651), 2-Benzyl-2-(dimethylamino)-1-[4-(morpholinyl) phenyl]-1-butanone (Irgacure 369), an initiator obtained by mixing 30 wt% of Irgacure 369 and 70 wt% of Irgacure 651 (Irgacure 1300), Diphenyl (2,4,6-trimethylbenzoyl)-phosphine oxide (Darocur TPO), an initiator obtained by mixing 50 wt% of Darocure TPO and 50 wt% of Darocur 1173 (Darocur 4265), Phosphine oxide, phenyl bis(2,4,6-trimethyl benzoyl) (Irgacure 819), 2-hydroxy-2-methyl-1-phenylpropane-1-one (Darocur 1173), an initiator obtained by mixing 5wt% of Irgacure 819 and 95 wt% of Darocure 1173 (Irgacure 2005), an initiator obtained by mixing 10 wt% of Irgacure 819 and 90 wt% of Darocure 1173 (Irgacure 2010), an initiator obtained by mixing 20 wt% of Irgacure 819 and 80 wt% of Darocure 1173 (Irgacure 2020), Bis(.eta. 5-2,4-cyclopentadien-1-yl) bis[2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl]titanium (Irgacure 784), a mixed initiator containing benzophenone (HSP 188), 1-hydroxy-cyclohexylphenyl-ketone (CPA), and 2,4,6,-trimethylbenzoyl-diphenyl-phosphineoxide (Darocur TPO). The additive may include one or more of a surfactant, an antifoaming agent, and a UV stabilizer.
According to various example embodiments, the multi-film 500 may be laminated on the polymer thin film 400. The multi-film 500 may protect the organic light emitting device 200 from the penetration of moisture and oxygen and damage caused by external shocks or scratches together with the hydrophobic oil 320.
According to various example embodiments, the encapsulated organic light emitting device 120 may include a moisture and oxygen barrier film formed in a desired shape in a short time at low production cost without using expensive equipment (for example, a physical/chemical vacuum chamber, and a vacuum pump) by encapsulation using the above-described hydrophobic oil 320, the polymer thin film 400, and the multi-film 500. Therefore, it is possible to easily manufacture a low-cost, light-weight, large-area device using the encapsulated organic light emitting device 120. Since the hydrophobic oil 320 and the multi-film 500 of the encapsulated organic light emitting device 120 block double moisture and oxygen, it is possible to increase the lifespan of the organic light emitting device 200 and improve the mechanical reliability and stability of the organic light emitting device 200 by effectively preventing the permeation of moisture and oxygen, which cause device degradation. In addition, the encapsulated organic light emitting device 120 may be bendable because it is based on the substrate 122 made from one of plastic, thin glass, and metal foil, plastics, and inorganic materials (for example, SiC, SiN, SiO, A12O3, A1N, SiON).
Referring to
Referring to
In operation 412, a hydrophobic oil (for example, the hydrophobic oil 320 of
In operation 414, a photo-curable precursor may be coated on surfaces of the hydrophobic oil 320 and the partition wall 310. The photo-curable precursor may be a combination of at least one of a reactive precursor, a photoinitiator, and an additive, and the reactive precursor may have a small miscibility with the hydrophobic oil 320 and a specific gravity of 1.0 to 1.2 which is less than the specific gravity of the hydrophobic oil 320.
In operation 416, the polymer thin film 400 may be formed by injecting light into the photo-curable precursor to induce a curing reaction of the photo-curable precursor. The photo-curable precursor may be cured in response to the light. UV light having a wavelength of 300 nm to 400 nm may be injected into the photo-curable precursor, and photocuring energy of 20 mJ to 2000 MJ may be used for the curing reaction.
Referring to
In operation 422, the encapsulated organic light emitting device 120 may include a housing structure defined by a partition wall (for example, the partition wall 310 of
In operation 424, the encapsulated organic light emitting device 120 may phase-separate the photo-curable precursor from the hydrophobic oil 320. The photo-curable precursor may be phase-separated due to the differences in miscibility and specific gravity from the hydrophobic oil 320 to be positioned on the surface of the hydrophobic oil 320.
In operation 426, the encapsulated organic light emitting device 120 may inject light into the phase-separated photo-curable precursor to induce a curing reaction of the photo-curable precursor to form a polymer thin film. The photo-curable precursor may be cured in response to the light. UV light having a wavelength of 300 nm to 400 nm may be injected into the photo-curable precursor, and photocuring energy of 20 mJ to 2000 mJ may be used for the curing reaction.
Referring to
According to various example embodiments, in the multi-film 500, the moisture absorption layer 530 may be inserted between the adhesive sheet 510 and the encapsulation layer 520 or a moisture absorbent may be added to the double-sided adhesive to absorb moisture and oxygen in the atmosphere. The moisture absorption layer and the moisture absorbent may include at least one of calcium, silica gel, zeolite, and alkali metal.
Referring to
In operation 610, the encapsulated organic light emitting device 120 may include a plurality of organic light emitting devices (for example, the organic light emitting device 200 of
In operation 620, the encapsulated organic light emitting device 120 may include the partition wall 310 disposed between the organic light emitting devices 200 to separate the plurality of organic light emitting devices 200. The partition wall 310 may have the PDL structure that separates the pixel boundary or may have another structure having the same function. The partition wall 310 may be formed using a photosensitive high heat-resistant organic material and may have a trapezoidal shape with a lower portion wider than an upper portion, and the height of the partition wall 310 may be 0.5 µm to 5 µm.
In operation 630, the housing structure defined by the partition wall 310 may be filled with the hydrophobic oil 320. The hydrophobic oil 320 may have excellent barrier properties against oxygen and moisture to be suitable for the barrier and heat-sink. The hydrophobic oil 320 may have a refractive index of 1.29 to 1.6, a contact angle with water of 90 degrees or more, and a specific gravity of 1.2 or more.
In operation 640, a polymer thin film (for example, the polymer thin film 400 of
In operation 650, a multi-film (for example, the multi-film 500 of
As described above, although the example embodiments have been described with reference to the limited drawings, those skilled in the art may apply various technical modifications and variations based thereon. For example, the described techniques may be performed in an order different from the described method, and/or the elements of the described system, structure, apparatus, circuit, etc. may be combined or organized in a different form from the described method or may be replaced or substituted by other elements or equivalents to achieve an appropriate result.
Therefore, other implementations, other example embodiments, and equivalents to the following claims also fall within the scope of the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2021-0117570 | Sep 2021 | KR | national |
