Light emitting electronic component and method for manufacturing light emitting electronic component

Abstract

To make the gap between substrates on which light emitting elements are placed difficult to see from the display side.SOLUTION: The present invention relates to a light emitting electronic component 1 which has a substrate 12 with two or more elements having the form of a plurality of light emitting elements 11 arranged on a substrate 10, a resin layer 21 in the state of being crimped to the substrate surface from above the plurality of light emitting elements 11 in the substrate with respective elements 12, and a coating layer 30 covering the gap 40 between substrates 12 with elements and the two or more resin layers 21 from the top of the two or more resin layers 21, in which the resin layer 30 is a layer that can transmit light from the light emitting element 11, and a method for manufacturing the same.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a light-emitting electronic component and a method for manufacturing a light-emitting electronic component. [Background technology]

[0002] In recent years, displays using extremely small light-emitting diodes called mini-LEDs or micro-LEDs have been attracting attention. There are roughly two known methods for using such extremely small light-emitting diodes in displays. One is to arrange a large number of light-emitting diodes on a substrate to form a backlight for liquid crystal, and to locally control the brightness of the backlight. The other is to make light-emitting diodes of each color (red, green, and blue) emit light, sending each color of light to the viewer's eyes on a pixel-by-pixel basis.

[0003] Light-emitting diodes such as mini LEDs or micro LEDs are generally arranged on a substrate. When multiple light-emitting diodes (referred to as light-emitting elements) are arranged on a substrate, it is necessary to prevent light diffusion between adjacent light-emitting elements. As a method for shielding light between multiple light-emitting elements with a resin having a light diffusion prevention function, for example, a method using a dry film is known (see Patent Document 1). The dry film is a film obtained by applying and drying a light-diffusing resin composition on a protective film.

[0004] When the dry film is pressed onto a plurality of light-emitting elements on a substrate, a light-diffusing resin layer is formed not only in the gaps between the light-emitting elements but also on the upper surface (light-emitting surface) of the light-emitting elements. Under such circumstances, the resin layer may block the light from reaching the viewer of the display. To prevent this, the above-mentioned conventional technology employs a method in which the light-emitting surface of the light-emitting element is etched by plasma treatment or the like to remove the resin layer on the light-emitting surface, and the removed surface is covered with a light-transmitting sealant.

[0005] However, the above-mentioned conventional technology requires a long time for the etching process, which leads to an increase in manufacturing costs. Also, it is difficult to completely remove the resin layer on the light-emitting surface of the light-emitting element, and as a result, it is difficult to completely prevent the diffusion of light that should reach the viewer side of the display. In addition, a step of laminating a highly transparent sealing film is required after the etching process, which increases the number of manufacturing processes.

[0006] As a sheet capable of solving the above problems, an encapsulating sheet is known in which a protective film (first layer), a highly light-transmitting curable resin layer (second layer), and a curable resin layer (third layer) with excellent light diffusion properties are arranged in that order (see Patent Document 2). By using the encapsulating sheet, it is possible to reduce the optical interference between light-emitting elements on a substrate and realize a structure that does not block light emitted from each light-emitting element. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent Publication No. 2022-22562 [Patent Document 2] China Patent Application Publication No. 114220902 Summary of the Invention [Problem to be solved by the invention]

[0008] However, because the encapsulating sheet is laminated for each substrate, when multiple substrates are arranged behind a large display, a user may be able to see the gaps between the substrates as seams from the display side. This situation may impair the appearance of the display.

[0009] The present invention has been made in view of the above-mentioned problems, and has an object to make the gaps between the substrates on which the light-emitting elements are arranged difficult to see from the display side. [Means for solving the problem]

[0010] (1) To achieve the above object, a light-emitting electronic component according to one embodiment comprises: Two or more element-mounted substrates each having a plurality of light-emitting elements disposed on the substrate; a resin layer that is pressure-bonded to a substrate surface from above the plurality of light-emitting elements in each of the element-mounted substrates; a covering layer that covers the gaps between the element-mounted substrates and the two or more resin layers from above the two or more resin layers; Equipped with The resin layer is a layer that is capable of transmitting light from the light emitting element. (2) In a light-emitting electronic component according to another embodiment, the resin layers may be laminated in the following order from the side closest to the substrate: a first resin layer, and a second resin layer having higher light transmittance than the first resin layer. (3) In the light-emitting electronic component according to another embodiment, the covering layer may preferably include a hard coat layer on the surface of the support film. (4) In the light-emitting electronic component according to another embodiment, the first resin layer may preferably contain a black pigment or dye. (5) In order to achieve the above object, a method for manufacturing a light-emitting electronic component according to one embodiment is a method for manufacturing any of the light-emitting electronic components described above, comprising the steps of: contacting the curable resin layer, in an uncured state, on the plurality of light-emitting elements; filling a portion of the curable resin layer between the plurality of light-emitting elements by pressing; A step of curing the curable resin layer after the press bonding; covering the gaps between the element-mounted substrates and the two or more resin layers with the covering layer from above the two or more cured resin layers; Includes. Effect of the Invention

[0011] According to the present invention, the gap between the substrates on which the light emitting elements are arranged can be made difficult to see from the display side. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a vertical cross-sectional view of a light-emitting electronic component according to an embodiment. [Diagram 2] FIG. 2 shows a vertical cross-sectional view of an encapsulating sheet having a curable resin layer in a state before the resin layer in FIG. 1 is cured. [Diagram 3] FIG. 3 shows a flow of main steps in manufacturing a light-emitting electronic component according to an embodiment. [Figure 4] FIG. 4 shows a cross-sectional view of an initial step in the flow of FIG. [Diagram 5] FIG. 5 shows a cross-sectional view of the intermediate process following FIG. [Figure 6] FIG. 6 shows a cross-sectional view of a later process subsequent to FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Next, an embodiment of the present invention will be described with reference to the drawings. Note that the embodiment described below does not limit the invention according to the claims, and not all of the elements and combinations described in the embodiment are necessarily essential to the solution of the present invention. In this specification and claims, the main component means a component that accounts for 50% by mass or more of the total solid content of the entire composition. A numerical range represented by "~" means a numerical range with the numbers before and after ~ as the lower and upper limits.

[0014] 1. Light-emitting electronic components FIG. 1 is a vertical cross-sectional view of a light-emitting electronic component according to an embodiment.

[0015] The light-emitting electronic component 1 according to this embodiment includes two or more element-mounted substrates 12 having a configuration in which a plurality of light-emitting elements 11 are arranged on a substrate 10, a resin layer 21 in each of the element-mounted substrates 12 being pressed against the substrate surface from above the plurality of light-emitting elements 11, and a covering layer 30 covering the gaps 40 between the element-mounted substrates 12 and the two or more resin layers 21 from above the two or more resin layers 21. The resin layer 21 is a layer that can transmit light from the light-emitting elements 11. It is sufficient for the covering layer 30 to cover at least a portion of the gaps 40 and at least a portion of the two or more resin layers 21, but it is preferably a single layer that covers all the gaps 40 and all the resin layers 30. Details of the light-emitting electronic component 1 will be described below.

[0016] (1) Substrate with elements The element-mounted substrate 12 has a plurality of light-emitting elements 11 arranged on a substrate 10. There are no particular restrictions on the material of the substrate 10, and a known printed circuit board can be suitably used. Known printed circuit boards include a glass epoxy substrate, a fluororesin substrate, a ceramic substrate, and a glass substrate.

[0017] The light emitting element 11 is typically a light emitting diode. This embodiment is particularly suitable for use when the light emitting element 11 is extremely small. For example, a light emitting diode having a height of 1000 nm to 200 μm and a side length of 0.001 to 0.5 mm can be used. As the element-mounted substrate 12 on which mini LEDs or micro LEDs are arranged, a substrate using light emitting diodes of three colors, R, G, and B, or a blue light emitting diode as the light emitting element 11 can be exemplified.

[0018] (2) Resin layer The resin layer 21 is preferably a layer laminated in the order of, from the side closer to the substrate 10, a black resin layer 22, which is an example of a first resin layer, and a transparent resin layer 23, which is an example of a second resin layer having higher light transmittance than the first resin layer.

[0019] [First resin layer] The black resin layer 22, which is an example of the first resin layer, is a layer filled in the gaps between the light emitting elements 11, and is preferably a layer having a thickness equal to or less than the height of the light emitting elements 11. A more suitable thickness of the black resin layer 22 is 0.1 to 0.9 times the height of the light emitting elements 11. When the thickness of the black resin layer 22 is 0.1 times or more the height of the light emitting elements 11, the function of preventing light diffusion between the light emitting elements 11 is sufficient. When the thickness of the black resin layer 22 is 0.9 times or less the height of the light emitting elements 11, the black resin layer 22 is unlikely to prevent the light from the light emitting elements 11 from reaching the viewer side.

[0020] The black resin layer 22 is a layer in a cured state of the curable first resin layer, as described later. The curable first resin layer is preferably a black curable resin layer. The black resin layer 22 is a layer capable of suppressing or preventing light diffusion (which may also be called optical interference) between the light emitting elements 11. To achieve this purpose, the black resin layer 22 preferably contains a black pigment or a black dye. However, the first resin layer is not limited to the black resin layer 22. The first resin layer does not have to be a black layer as long as it is a layer with lower optical transparency than the second resin layer.

[0021] (Main material) The black resin layer 22 mainly contains at least one resin selected from the group consisting of epoxy resin, acrylic resin, polyester resin, polyurethane resin, and silicone resin. Among these resins, epoxy resin is preferred because it can be cured at low temperatures and has excellent heat resistance and reliability. Epoxy resin will be described in detail in the section on the encapsulating sheet.

[0022] (Black pigment or black dye) The black resin layer 22 is preferably colored black. For coloring, the black resin layer 22 preferably contains a black pigment or a black dye, more preferably contains a black pigment, and further preferably contains carbon black. By coloring the black resin layer 22 black, a high light diffusion prevention function between the multiple light emitting elements 11 of the element-mounted substrate 12 can be obtained.

[0023] The particle size of carbon black, which is an example of a black pigment, is preferably 10 to 500 nm, more preferably 10 to 300 nm, and even more preferably 10 to 100 nm. In this embodiment, the "particle size" refers to the average particle size, and can be determined by a measuring device using a dynamic light scattering method. An example of a measuring device using the dynamic light scattering method is NanotracWave II UT151 manufactured by Microtrack Bell.

[0024] As the carbon black, one or more of known carbon blacks such as gas black, channel black, furnace black, thermal black, and lamp black can be used. Resin-coated carbon black may also be used. Furthermore, carbon nanofibers and carbon nanotubes may also be used.

[0025] Among the above carbon blacks, gas black is preferred because it has a large amount of surface functional groups, has high dispersibility, and exerts a sufficient light diffusion preventing function even when added in a small amount. In addition, when the uncured black curable resin layer of the black resin layer 22 contains a modified elastomer having a functional group capable of reacting with an epoxy resin, the dispersibility is further increased due to the interaction between the surface functional groups of the gas black and the functional groups of the modified elastomer having a functional group capable of reacting with an epoxy resin, and good light diffusion preventing properties and coating liquid stability can be ensured.

[0026] The amount of carbon black is preferably 0.1 to 15 mass %, more preferably 0.3 to 5 mass %, based on the total solid content of the black curable resin layer. When the amount of carbon black is equal to or more than the lower limit, sufficient light blocking properties can be obtained. When the amount of carbon black is equal to or less than the upper limit, the thixotropy of the black curable resin layer can be kept low, a decrease in fluidity during thermocompression bonding can be prevented, and the black curable resin layer can be sufficiently filled between the multiple light emitting elements 11 of the element-mounted substrate 12.

[0027] (Other Ingredients) The black resin layer 22 may contain an inorganic filler to improve flame retardancy or heat resistance or to adjust the refractive index. The black resin layer 22 may further contain, as necessary, a resin other than the epoxy resin and the elastomer, a thickener, a defoamer and / or a leveling agent, an adhesion imparting agent such as a coupling agent, and a flame retardant.

[0028] (Lab value) In the black resin layer 22, the Lab values ​​measured in accordance with JIS Z8722 using a light source of D65, a field of view of 2°, and a transmission method are preferably L: 5 to 60, a: -3 to 7, and b: -20 to 20, and more preferably L: 10 to 50, a: -2 to 5, and b: -15 to 15. When the Lab values ​​in the black resin layer 22 are in the above-mentioned preferred ranges, light diffusion between the light emitting elements 11 can be further prevented, and the contrast of the display can be further improved.

[0029] (Total light transmittance) The total light transmittance of the black resin layer 22 is lower than that of the transparent resin layer 23. Specifically, the total light transmittance of the black resin layer 22 is preferably adjusted to be 0 to 50%. The total light transmittance is more preferably adjusted to be 0 to 40%, and even more preferably adjusted to be 0 to 30%. When the total light transmittance is equal to or less than the upper limit value such as 50%, 40%, or 30%, light diffusion between the light emitting elements 11 can be further prevented. The total light transmittance in this specification can be measured by a haze meter in accordance with JIS K 7136. The total light transmittance can be changed mainly by the presence or absence of carbon black, the amount of carbon black, the thickness of the black resin layer 22, and the type of resin as the main material.

[0030] [Second resin layer] The transparent resin layer 23, which is an example of the second resin layer, is a layer having a higher light transmittance than the black resin layer 22. The transparent resin layer 23 is a layer located mainly above the light emitting surface (upper surface) of the light emitting element 11. However, a part of the transparent resin layer 23 may be present on the side surface of the light emitting element 11. The transparent resin layer 23 is a layer that transmits light emitted from the light emitting element 11 in the thickness direction of the transparent resin layer 23, and therefore is a layer having a higher light transmittance than the black resin layer 22. The second resin layer is not limited to the transparent resin layer 23. The second resin layer does not need to be a transparent layer as long as it is a layer having a higher light transmittance than the first resin layer. The more preferable thickness of the transparent resin layer 23 is 0.1 to 5.0 times the height of the light emitting element 11. When the thickness of the transparent resin layer 23 is 0.1 times or more the height of the light emitting element 11, the transparent resin layer 23 is likely to function as a sealing layer that covers the light emitting element 11. When the thickness of the transparent resin layer 23 is 5.0 times or less the height of the light-emitting element 11, even if the transparency of the transparent resin layer 23 is slightly low, the transparent resin layer 23 is unlikely to hinder the transmission of light from the light-emitting element 11.

[0031] (Main material) The transparent resin layer 23 mainly contains at least one resin selected from epoxy resin, acrylic resin, polyester resin, polyurethane resin, and silicone resin, similar to the black resin layer 22. Among these resins, epoxy resin is preferable because it can be cured at low temperature and has excellent heat resistance and reliability.

[0032] (Other Ingredients) The transparent resin layer 23 may contain a black pigment or black dye to suppress uneven light emission and color, provided that the transparent resin layer 23 has a higher light transmittance than the black resin layer 22 .

[0033] (Total light transmittance) The total light transmittance of the transparent resin layer 23 is preferably adjusted to be 30 to 99%. The total light transmittance is more preferably adjusted to be 35 to 95%, and even more preferably adjusted to be 40 to 90%. When the total light transmittance is equal to or greater than the above lower limit, even if the transparent resin layer 23 is located above the light emitting element 11, the light is less likely to be prevented from reaching the viewer's side.

[0034] (3) Covering layer The covering layer 30 is a layer that covers the multiple element-mounted substrates 12. The covering layer 30 is preferably a semi-transparent layer, and is a layer having lower light transmittance than the transparent resin layer 23. However, the light transmittance of the covering layer 30 may be the same as that of the transparent resin layer 23.

[0035] In this specification, "semi-transparent" refers to a transparency between completely transparent and completely opaque, and refers to a property in which the total light transmittance measured using a haze meter in accordance with JIS K 7136 is 30% or more and 95% or less.

[0036] The covering layer 30 covers the plurality of resin layers 21 including the gaps 40 between the element-mounted substrates 12. Therefore, when the plurality of element-mounted substrates 12 are arranged on the back side of the display, the covering layer 30 has a function of making the gaps 40 difficult to see from the front of the display. The covering layer 30 has a function of protecting the resin layer 21 from external damage. The covering layer 30 preferably has a hard coat layer 33 on the surface of the support film 32. The covering layer 30 may have a coating layer on the support film 32 in place of the hard coat layer 33. The coating layer is a layer for adjusting the total light transmittance of the covering layer 30 to an appropriate value. The covering layer 30 may also have a hard coat layer 33 on the coating layer. Furthermore, the covering layer 30 may be only the support film 32. The covering layer 30 can be fixed to the transparent resin layer 23 of the resin layer 21 via, for example, an adhesive layer 31.

[0037] (Total light transmittance) The total light transmittance of the coating layer 30 is preferably 30% or more and 95% or less, more preferably 40% or more and 90% or less. When the total light transmittance is equal to or more than each of the lower limits, light is less likely to be prevented from reaching the viewer side.

[0038] Next, each member constituting the coating layer 30 will be described.

[0039] [Support film] The support film 32 is a layer for protecting the light emitting element 11 from external physical impact, humidity, moisture, etc. The support film 32 also serves as a support for forming layers such as a curable resin layer described below, the coating layer described above, and the hard coat layer 33.

[0040] (Main material) The support film 32 may be mainly composed of a thermoplastic resin or a thermosetting resin. Examples of the main resins constituting the support film 32 include polyethylene terephthalate resin, polybutylene terephthalate resin, polyethylene 2,6-naphthalate resin, polyamide resin, polycarbonate resin, polycarbonate copolymer resin, triacetyl cellulose resin, polymethylpentene resin, phenoxy resin, syndiotactic polystyrene resin, polyimide resin, etc., and at least one resin selected from polyethylene terephthalate resin, polyethylene 2,6-naphthalate resin, polycarbonate resin, polycarbonate copolymer resin, and polyamide resin can be exemplified in terms of heat resistance, weather resistance, ease of availability, cost, etc. By mainly including the above resin in the support film 32, deformation when fixing the coating layer 30 to the resin layer 21 can be prevented. The support film 32 may contain a black pigment or black dye to suppress uneven light emission and color unevenness.

[0041] (Film thickness) The thickness of the support film 32 is preferably 10 to 250 μm, more preferably 20 to 225 μm, and even more preferably 25 to 150 μm. When the thickness of the support film 32 is equal to or greater than the preferred lower limit, the generation of wrinkles when the support film 32 is fixed to the resin layer 21 can be suppressed, and the handleability can be improved. When the thickness of the support film 32 is equal to or less than the preferred upper limit, the effects of improved visibility and reduced costs can be obtained.

[0042] (Total light transmittance) The support film 32 is preferably adjusted to have a total light transmittance of 30 to 99%, more preferably 35 to 95%, and even more preferably 40 to 95%. When the total light transmittance of the support film 32 is equal to or greater than the above-mentioned lower limit, light is less likely to be prevented from reaching the viewer's side.

[0043] [Hard coat layer] (Main material of hard coat layer) The main material of the hard coat layer 33 may contain either a thermoplastic resin or a thermosetting resin, and preferably contains a thermosetting resin. Examples of the thermosetting resin constituting the hard coat layer 33 include an acrylic resin, a urethane resin, a silicone resin, a melamine resin, and the like, and the hard coat layer 33 may contain one or more of these. The hard coat layer 33 may contain a black pigment or dye.

[0044] (fine particles) The hard coat layer 33 preferably contains fine particles. As the fine particles, one or both of inorganic fine particles and organic fine particles can be used. As inorganic fine particles, silica fine particles and titanium fine particles can be mentioned. As organic fine particles, polymethyl methacrylate resin (PMMA resin) and urethane resin can be mentioned. Among these fine particles, silica fine particles are preferable. By including fine particles in the hard coat layer 33, it is possible to adjust the surface roughness of the hard coat layer 33 and to improve the surface hardness.

[0045] (hardness) The hard coat layer 33 is a layer for effectively protecting the light-emitting electronic component 1 from scratches. The pencil hardness of the surface of the hard coat layer 33 is preferably H or more, more preferably 2H or more, and even more preferably 3H or more.

[0046] (Surface roughness) The arithmetic surface roughness (Ra) of the surface of the hard coat layer 33 is preferably 0.1 to 1 μm, more preferably 0.2 to 1 μm, and even more preferably 0.3 to 1 μm. When the Ra of the hard coat layer 33 is equal to or greater than the preferred lower limit, the reflectance of the surface of the hard coat layer 33 can be reduced. When the Ra of the hard coat layer 33 is equal to or less than the preferred upper limit, production becomes easier.

[0047] (Total light transmittance) The total light transmittance of the hard coat layer 33 is adjusted to be preferably 30 to 99%, more preferably 50 to 99%, and further more preferably 60 to 99%. When the total light transmittance of the hard coat layer 33 is equal to or greater than the lower limit, light is not prevented from reaching the viewer side.

[0048] (Film thickness) The thickness of the hard coat layer 33 is preferably 1 to 20 μm, more preferably 2 to 10 μm, and even more preferably 3 to 8 μm. When the thickness of the hard coat layer 33 is equal to or greater than the preferred lower limit, sufficient hardness can be ensured. When the thickness of the hard coat layer 33 is equal to or less than the preferred upper limit, problems such as curling of the coating layer 30 can be prevented.

[0049] (reflectance) The reflectance measured by a gloss meter (JIS-Z-8741) on the hard coat layer 33 side is preferably 1 to 50%, more preferably 3 to 30%, and even more preferably 5 to 25%. If the reflectance is equal to or higher than the lower limit, production is easy. If the reflectance is equal to or lower than the preferred upper limit, the visibility of the display is improved.

[0050] 2. Encapsulating sheet Next, the encapsulating sheet 20 including the curable resin layer in a state before curing of the resin layer 21 to be pressure-bonded and filled in the element-mounted substrate 12 will be described.

[0051] FIG. 2 shows a vertical cross-sectional view of an encapsulating sheet having a curable resin layer in a state before the resin layer in FIG. 1 is cured.

[0052] In this embodiment, the encapsulating sheet 20 preferably includes protective sheets 25, 26 on both sides of the curable resin layer 21a in the thickness direction. The curable resin layer 21a is a layer of the resin layer 21 in a pre-cured state. The curable resin layer 21a is a layer including at least a curable first resin layer and a curable second resin layer. The protective sheet 25 is attached to the black curable resin layer 22a, which is an example of the curable first resin layer, in an easily separable state. The protective sheet 26 is attached to the transparent curable resin layer 23a, which is an example of the curable second resin layer, in an easily separable state. The black curable resin layer 22a is a layer of the black resin layer 22 in a pre-cured state. The transparent curable resin layer 23a is a layer of the transparent resin layer 23 in a pre-cured state. The encapsulating sheet 20 can be manufactured, for example, by the following method. First, the black curable resin layer 22a is formed on one side of the protective sheet 25. Next, a transparent curable resin layer 23a is formed on one surface of the protective sheet 26. Finally, the black curable resin layer 22a of the protective sheet 25 and the transparent curable resin layer 23a of the protective sheet 26 are bonded together to complete the encapsulating sheet 20. The curable resin layer 21a of the encapsulating sheet 20 is pressure-bonded to the surface of the element-mounted substrate 12 on which the multiple light-emitting elements 11 are arranged.

[0053] A more detailed manufacturing method of the encapsulating sheet 20 is as follows. To obtain the encapsulating sheet 20, first, a protective sheet 25 is prepared by applying a coating liquid of a curable resin composition for the black curable resin layer 22a to one side thereof and drying it, and a protective sheet 26 is prepared by applying a coating liquid of a curable resin composition for the transparent curable resin layer 23a to one side thereof and drying it. Then, these are stacked and laminated so that the transparent curable resin layer 23a and the black curable resin layer 22a are in contact with each other, thereby obtaining the encapsulating sheet 20 in which the protective sheet 25, the black curable resin layer 22a, the transparent curable resin layer 23a, and the protective sheet 26 are stacked in this order.

[0054] The coating liquid of the curable resin composition of the black curable resin layer 22a and / or the coating liquid of the curable resin composition of the transparent curable resin layer 23a preferably contains an organic solvent in an amount that provides a viscosity that allows coating without hindrance. The organic solvent is not particularly limited, but examples thereof include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, and petroleum-based solvents. Specific examples of the organic solvent include ketones such as methyl ethyl ketone, cyclohexanone, methyl butyl ketone, and methyl isobutyl ketone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, and triethylene glycol monoethyl ether; ethyl acetate, butyl acetate, isobutyl acetate, ethyl ... Examples of the solvent include esters such as propylene glycol monoethyl ether acetate, dipropylene glycol methyl ether acetate, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, and propylene glycol butyl ether acetate; alcohols such as ethanol, propanol, 2-methoxypropanol, n-butanol, isobutyl alcohol, isopentyl alcohol, ethylene glycol, and propylene glycol; aliphatic hydrocarbons such as octane and decane; petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha, as well as N,N-dimethylformamide (DMF), tetrachloroethylene, and turpentine. When carbon black is blended into the coating liquid, carbon black powder may be added, or a liquid in which carbon black has been previously dispersed (carbon black dispersion) may be added.

[0055] Examples of the method for applying the curable resin composition include various coaters such as a die coater, a gravure coater, a roll coater, a curtain flow coater, a spin coater, a bar coater, a reverse coater, a kiss coater, a fountain coater, a rod coater, an air doctor coater, a knife coater, a blade coater, a cast coater, a screen coater, etc. The drying temperature is preferably 60 to 160°C, more preferably 80 to 130°C, and even more preferably 90 to 120°C.

[0056] The temperature during lamination is preferably 20 to 120°C, more preferably 30 to 100°C, and even more preferably 40 to 80°C. By setting the temperature during lamination to a preferable lower limit or higher, it is possible to ensure adhesion between the black curable resin layer 22a and the transparent curable resin layer 23a that allows handling even when uncured. In addition, by setting the temperature during lamination to a preferable upper limit or lower, it is possible to prevent the formation of air bubbles and wrinkles. Lamination can be performed using, for example, a roll laminator, a press machine, a vacuum press machine, or the like.

[0057] Next, the black curable resin layer 22a, which is an example of the first curable resin layer, the transparent curable resin layer 23a, which is an example of the second curable resin layer, and the protective sheets 25 and 26 will be described.

[0058] (1) Curable first resin layer The black curable resin layer 22a, which is an example of the curable first resin layer, becomes the black resin layer 22 by curing, and is a layer for preventing light diffusion between the light emitting elements 11 and improving the contrast of the display. The black curable resin layer 22a also serves to sufficiently fill the gaps between the multiple light emitting elements 11 arranged on the element-mounted substrate 12 in a pressure bonding process represented by thermocompression bonding, and to prevent poor appearance due to expansion of unfilled gaps in a curing process represented by thermosetting, and damage to the light emitting elements 11 due to external factors in a later process.

[0059] Before compression bonding, the thickness of the black curable resin layer 22a is preferably 10 to 95% of the height of the light emitting element 11. The lower limit is more preferably 15% or more, and even more preferably 30% or more. The upper limit is more preferably 85% or less, and even more preferably 75% or less.

[0060] When the thickness of the black curable resin layer 22a is 10% or more of the height of the light emitting element 11, the function of preventing light diffusion between the light emitting elements 11 is sufficient. In addition, when the storage modulus of the black curable resin layer 22a is relatively low and the layer 22a is highly fluid, the resin can be sufficiently filled between the light emitting elements 11. When the thickness of the black curable resin layer 22a is 15% or more of the height of the light emitting element 11, even if the fluidity of the transparent curable resin layer 23a described below is relatively low, crack-like defects are unlikely to occur on the surface. When the thickness of the black curable resin layer 22a is 30% or more of the height of the light emitting element 11, the black curable resin layer 22a having the light diffusion prevention function can be appropriately filled between the light emitting elements 11.

[0061] If the thickness of the black curable resin layer 22a is 95% or less of the height of the light emitting element 11, leakage of the black curable resin layer 22a to the outside during thermocompression bonding can be prevented, and light from the light emitting element 11 is less likely to be hindered from reaching the viewer. If the thickness of the black curable resin layer 22a is 85% or less of the height of the light emitting element 11, the film thickness of the black curable resin layer 22a that flows after pressing is less likely to vary, and black shading is less likely to occur. If the thickness of the black curable resin layer 22a is 75% or less of the height of the light emitting element 11, the black curable resin layer 22a having a light diffusion prevention function can be appropriately filled between the light emitting elements 11.

[0062] (Main material) The black curable resin layer 22a includes a curable resin composition. An example of the curable resin composition is a curable resin composition including at least one resin selected from an epoxy resin, an acrylic resin, a polyester resin, a polyurethane resin, and a silicone resin, and a curing agent. Among the above curable resin compositions, an epoxy resin composition that can achieve curing at low temperatures and has excellent heat resistance and reliability is preferred. In this specification, the epoxy resin composition is a composition that includes an epoxy resin as a main component, or a composition that includes an epoxy resin and a curing agent as main components.

[0063] When the black curable resin layer 22a is made of an epoxy resin composition, it may contain a curing agent for epoxy resin other than the modified elastomer having a functional group capable of reacting with an epoxy group. Examples of the other curing agent include known curing agents such as phenol-based curing agents, acid anhydride-based curing agents, and amine-based curing agents. Two or more types of the other curing agents may be used in combination.

[0064] In the present application, an epoxy resin is a compound having an epoxy group in a molecule. The epoxy resin used in this embodiment is preferably one having two or more epoxy groups in one molecule. This is because a crosslinked structure is formed by reaction with a modified resin having a functional group capable of reacting with an epoxy group, and the cured product can exhibit high heat resistance. In addition, when an epoxy resin having two or more epoxy groups is used, the degree of crosslinking with a curing agent having a functional group capable of reacting with an epoxy group is sufficient, and sufficient heat resistance is obtained in the cured product.

[0065] Examples of epoxy resins include bifunctional epoxy resins having two epoxy groups in a molecule, polyfunctional epoxy resins having three or more epoxy groups in a molecule, and high molecular weight epoxy resins having a weight average molecular weight of 10,000 or more. They may also be hydrogenated epoxy resins. In this application, high molecular weight epoxy resins are not classified as bifunctional epoxy resins or polyfunctional epoxy resins, but as phenoxy-type epoxy resins, regardless of the number of epoxy groups in the molecule. The weight average molecular weight of an epoxy resin is a polystyrene-equivalent molecular weight measured by gel permeation chromatography.

[0066] Examples of epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, phenoxy type epoxy resins obtained by polymerizing these resins, and hydrogenated versions of these resins; glycidyl ester-based epoxy resins such as diglycidyl phthalate, diglycidyl isophthalate, diglycidyl terephthalate, glycidyl p-hydroxybenzoate, diglycidyl tetrahydrophthalate, diglycidyl succinate, diglycidyl adipic acid, diglycidyl sebacate, and triglycidyl trimellitate; ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, Examples of the epoxy resins include, but are not limited to, glycidyl ether-based epoxy resins such as 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, tetraphenylglycidyl ether ethane, triphenylglycidyl ether ethane, polyglycidyl ether of sorbitol, and polyglycidyl ether of polyglycerol; glycidylamine-based epoxy resins such as triglycidyl isocyanurate and tetraglycidyl diaminodiphenylmethane; and linear aliphatic epoxy resins such as epoxidized polybutadiene and epoxidized soybean oil. In addition, novolac-type epoxy resins such as xylene structure-containing novolac epoxy resins, naphthol novolac-type epoxy resins, phenol novolac epoxy resins, o-cresol novolac epoxy resins, and bisphenol A novolac epoxy resins can also be used.

[0067] Examples of epoxy resins include brominated bisphenol A type epoxy resins, phosphorus-containing epoxy resins, fluorine-containing epoxy resins, dicyclopentadiene skeleton-containing epoxy resins, naphthalene skeleton-containing epoxy resins, anthracene type epoxy resins, tertiary butyl catechol type epoxy resins, triphenylmethane type epoxy resins, tetraphenylethane type epoxy resins, biphenyl type epoxy resins, and bisphenol S type epoxy resins.

[0068] Examples of high molecular weight epoxy resins that can be used include phenoxy type epoxy resins, epoxy modified polybutadiene, copolymers of glycidyl methacrylate and methyl methacrylate, modified polymers obtained by epoxy modifying other resins, etc. These epoxy resins may be used alone or in combination of two or more.

[0069] Among the above epoxy resins, the epoxy resin used in the black curable resin layer 22a is preferably a multifunctional epoxy resin from the viewpoint of increasing the crosslink density after curing. Among the multifunctional epoxy resins, novolac-type epoxy resins are particularly preferable for the following reasons. Novolac-type epoxy resins are epoxy resins that can be appropriately introduced with a flexible skeleton and can adjust the flexibility and softening point. This makes the cured product less likely to undergo brittle fracture, improves the stability of performance over long-term use of the cured product of the epoxy resin composition, increases the crosslink density, and improves heat resistance.

[0070] Specific examples of novolac-type epoxy resins include "YX7700" manufactured by Mitsubishi Chemical Corporation, "NC7000L", "XD1000", and "EOCN-1020" manufactured by Nippon Kayaku Co., Ltd., "ESN485" manufactured by Nippon Steel Chemical & Material Co., Ltd., and "N-690", "N-695", and "HP-7200H" manufactured by DIC Corporation.

[0071] The amount of the polyfunctional epoxy resin in the black curable resin layer 22a is preferably 10 to 99% by mass, more preferably 40 to 95% by mass, and even more preferably 60 to 90% by mass, based on 100% by mass of the total resin solid content of the black curable resin layer 22a. When the amount is equal to or greater than the lower limit, the crosslinking density can be increased to provide chemical resistance and heat resistance. When the amount is equal to or less than the upper limit, the storage modulus during thermocompression bonding can be adjusted, and the fluidity of the black curable resin layer 22a can be ensured.

[0072] The black curable resin layer 22a does not contain a high molecular weight epoxy resin, or if it contains a high molecular weight epoxy resin, it preferably contains it in a smaller amount than the transparent curable resin layer 23a. This makes it easier to ensure sufficient fluidity during thermocompression bonding. The amount of high molecular weight epoxy resin in the black curable resin layer 22a is preferably less than 50% by mass, more preferably less than 30% by mass, and even more preferably less than 10% by mass, relative to 100% by mass of the total resin solid content of the black curable resin layer 22a.

[0073] From the viewpoint of ensuring sufficient fluidity during thermocompression bonding, the black curable resin layer 22a preferably contains an epoxy resin having a softening point or melting point of 100° C. or less. Furthermore, in order to improve handling properties and the heat resistance of the cured product, the black curable resin layer 22a more preferably contains an epoxy resin having a softening point or melting point of 40 to 95° C. By containing an epoxy resin having a softening point or melting point within the above range, it becomes possible to control the storage modulus.

[0074] The total amount of epoxy resin in the black curable resin layer 22a is preferably 10 to 100% by mass, more preferably 20 to 99% by mass, and even more preferably 35 to 95% by mass, relative to 100% by mass of the total resin solid content of the black curable resin layer 22a. Within the above range, the storage modulus of the black curable resin layer 22a can be controlled, and appropriate fluidity during thermocompression bonding can be ensured. Furthermore, if the amount is equal to or greater than the above lower limit, the heat resistance of the black curable resin layer 22a after curing can be improved.

[0075] (Elastomer) The black curable resin layer 22a preferably contains an elastomer in addition to a resin such as an epoxy resin, etc. By containing an elastomer, it becomes easier to control the storage modulus, that is, the fluidity.

[0076] As the elastomer, a thermosetting elastomer, generally called "rubber", is preferred because it provides excellent heat resistance. Examples of thermosetting elastomers include acrylonitrile butadiene rubber (NBR), which is a random copolymer of butadiene and acrylonitrile, acrylic rubber, styrene butadiene rubber, vinyl acetate resin, silicone resin, and the like. Among these, NBR is preferred because NBR has good compatibility with epoxy resins. As a result, it becomes possible to control the fluidity of the black curable resin layer 22a at around 100°C, and the adhesion to the transparent curable resin layer 23a and the element-mounted substrate 12 becomes good.

[0077] The weight average molecular weight of the elastomer is preferably 100,000 to 1,000,000, more preferably 120,000 to 500,000, and further preferably 150,000 to 300,000. When the weight average molecular weight of the elastomer is within the above range, the storage modulus of the black curable resin layer 10 can be controlled, and the flowability during thermocompression bonding can be ensured. When the weight average molecular weight of the elastomer is equal to or less than the above upper limit, the compatibility with the epoxy resin is improved, and the flowability during thermal curing can be more effectively controlled.

[0078] In particular, when the black curable resin layer 22a is composed of an epoxy resin composition, the black curable resin layer 22a preferably contains a modified elastomer having a functional group capable of reacting with an epoxy group. The reasons are as follows. The modified elastomer having a functional group capable of reacting with an epoxy group also acts as a curing agent for the epoxy resin. In addition, the modified elastomer can react with and bond to the epoxy resin, improving the heat resistance and reliability against thermal shock. Furthermore, the difference in polarity between the functional group capable of reacting with the epoxy resin and the resin skeleton has a favorable effect on dispersibility, and good dispersibility can be obtained when carbon black is contained in the black curable resin layer 22a.

[0079] Examples of functional groups that can react with epoxy groups include acid groups such as carboxy groups, sulfo groups, nitro groups, and phosphoric acid groups, as well as their acid anhydride groups, hydroxyl groups, and amino groups. Among these groups, acid groups and acid anhydride groups are preferred because they can be cured at low temperatures and can ensure a long working life. Furthermore, carboxy groups and carboxylic anhydride groups are more preferred.

[0080] That is, when the black curable resin layer 22a is composed of an epoxy resin composition, it preferably contains an acid-modified elastomer having an acid group or an acid anhydride group, more preferably contains an acid-modified elastomer having a carboxy group, and even more preferably contains modified NBR having a carboxy group.

[0081] The modified NBR having a carboxy group is preferably a carboxylated acrylonitrile rubber into which acrylic acid, methacrylic acid, maleic anhydride, etc. are introduced. Commercially available products of the carboxylated acrylonitrile rubber include Nipol (registered trademark) NX775 and Nipol 1072CGJ manufactured by Zeon Corporation. Two or more types of modified elastomers having a functional group capable of reacting with an epoxy group may be used in combination.

[0082] The amount of elastomer in the black curable resin layer 22a is preferably greater than the amount of elastomer in the transparent curable resin layer 23a. As a result, the black curable resin layer 22a contains a large amount of low molecular weight components such as polyfunctional epoxy, so that the storage modulus of the black curable resin layer 22a during thermocompression bonding can be adjusted to an appropriate range lower than that of the transparent curable resin layer 23a, and flow during thermal curing can be suppressed. As a result, sufficient flow during thermocompression bonding in the black curable resin layer 22a and suppression of outflow during thermal curing can be achieved.

[0083] The amount of the elastomer in the black curable resin layer 22a is preferably 0.01 to 90% by mass, more preferably 1 to 80% by mass, and even more preferably 5 to 65% by mass, based on 100% by mass of the total resin solid content of the black curable resin layer 22a. Within the above range, the storage modulus can be controlled, and appropriate fluidity during thermocompression bonding can be ensured. Furthermore, when the amount is equal to or greater than the above lower limit, the dispersibility of carbon black is improved. Furthermore, the film-forming property is improved, and the film thickness distribution can be narrowed when the epoxy resin composition is applied to form a film.

[0084] (hardening agent) When the black curable resin layer 22a is made of an epoxy resin composition, it may contain a curing agent for epoxy resin other than the modified elastomer having a functional group capable of reacting with an epoxy group. Examples of the other curing agent include known curing agents such as phenol-based curing agents, acid anhydride-based curing agents, and amine-based curing agents. Two or more types of the other curing agents may be used in combination.

[0085] (curing catalyst) When the black curable resin layer 22a is made of an epoxy resin composition, it may contain a curing catalyst that promotes the curing reaction of the epoxy resin. Examples of the curing catalyst include imidazole-based, tertiary amine-based, and phosphorus compound-based. Among them, imidazole-based catalysts are preferred because they are compatible with epoxy resins and do not easily cause yellowing. Among imidazole-based curing catalysts, those having a cyanoethyl group are particularly preferred. This is because they are easily dissolved in epoxy resins. The amount of the curing catalyst is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 4 parts by mass, and even more preferably 0.1 to 3 parts by mass, relative to 100 parts by mass of the total resin solid content of the black curable resin layer 22a. Within the above range, curing can be sufficiently promoted and the usable time of the curable resin layer 21a can be secured. Two or more types of curing catalysts may be used in combination.

[0086] (Storage modulus) The storage modulus of the black curable resin layer 22a in an uncured state is preferably smaller than the storage modulus of the transparent curable resin layer 23a in an uncured state. The storage modulus of the black curable resin layer 22a in an uncured state is preferably 1.0×10 5 Pa or less, more preferably 1.0×10 2 Pa or more 1.0×10 5 Pa or less, and even more preferably 1.0×10 3 Pa or more 5.0×10 4 Pa or less. By having the storage modulus be equal to or less than the above upper limit, sufficient fluidity can be obtained during compression bonding to the element-mounted substrate 12, and the gaps between the plurality of light-emitting elements 11 can be sufficiently filled by following the unevenness of the element-mounted substrate 12 caused by the plurality of light-emitting elements 11. Furthermore, by having the storage modulus be equal to or more than the above lower limit, it is possible to prevent uneven pressure during thermocompression bonding, and a uniform appearance can be maintained. Furthermore, it is possible to prevent the resin from flowing out of the desired range, and it is possible to ensure the film thickness after compression bonding.

[0087] (2) Curable second resin layer The transparent curable resin layer 23a, which is an example of the curable second resin layer, is cured to become the transparent resin layer 23. The curable second resin layer 22a is a layer for sufficiently pressing the black curable resin layer 22a between the multiple light emitting elements 11 arranged on the element-mounted substrate 12 in the thermocompression bonding process.

[0088] The thickness of the transparent curable resin layer 23a before compression bonding is preferably 10 to 500% of the height of the light emitting element 11. The lower limit is more preferably 20% or more, and even more preferably 30% or more. The upper limit is more preferably 200% or less, and even more preferably 150% or less.

[0089] When the thickness of the transparent curable resin layer 23a is 10% or more of the height of the light emitting element 11, the cured transparent curable resin layer 23a is likely to function as a sealing layer covering the light emitting element 11. In addition, when the storage modulus of the transparent curable resin layer 23a is relatively high and the fluidity of the transparent curable resin layer 23a is suppressed, the transparent curable resin layer 23a can be suppressed from flowing together with the black curable resin layer 22a during thermal curing, and appearance defects are unlikely to occur on the surface. When the thickness of the transparent curable resin layer 23a is 20% or more of the height of the light emitting element 11, the range in which the transparent curable resin layer 23a can flow is sufficient, and crack-like defects are unlikely to occur on the surface. When the thickness of the transparent curable resin layer 23a is 30% or more of the height of the light emitting element 11, the cured transparent curable resin layer 23a is likely to function as a sealing layer covering the light emitting element 11. Furthermore, when the storage modulus of the transparent curable resin layer 23a is relatively high and the fluidity of the layer 23a is suppressed, the transparent curable resin layer 23a can sufficiently press into the black curable resin layer 22a.

[0090] The total thickness of the black curable resin layer 22a and the transparent curable resin layer 23a before compression bonding is preferably 110 to 550% of the height of the light emitting element 11. If the total thickness is equal to or greater than the above-mentioned lower limit value with respect to the height of the light emitting element 11, a part of the curable resin layer 21a of the encapsulating sheet 20 can be sufficiently embedded between the light emitting elements 11. If the total thickness is equal to or less than the above-mentioned upper limit value with respect to the height of the light emitting element 11, thickness unevenness is unlikely to occur during compression bonding, and appearance defects are unlikely to occur on the surface.

[0091] The ratio of the thickness of the black cured resin layer 22a before compression to the total thickness of the transparent cured resin layer 23a and the black cured resin layer 22a before compression is preferably 10 to 90%, more preferably 15 to 70%. If the thickness ratio is equal to or greater than the lower limit, the degree of blackness can be increased and the contrast of the display can be sufficiently improved. If the thickness ratio is equal to or less than the upper limit, the black cured resin layer 22a is unlikely to remain on the light emitting element 11 during compression, and the brightness can be sufficiently improved.

[0092] (Main material) The transparent curable resin layer 23a is composed of a curable resin composition. As with the black curable resin layer 22a, the curable resin composition may be a curable resin composition containing at least one resin selected from epoxy resin, acrylic resin, polyester resin, polyurethane resin, and silicone resin, and a curing agent. Among them, an epoxy resin composition is preferred because it can be cured at low temperature and has excellent heat resistance and reliability.

[0093] Examples of epoxy resins used in the transparent curable resin layer 23a include the same types as those used in the black curable resin layer 22a. From the viewpoint of imparting an appropriate viscosity during compression to the transparent curable resin layer 23a, the transparent curable resin layer 23a preferably contains a high molecular weight epoxy resin having a weight average molecular weight of 10,000 to 100,000. From the viewpoint of having good compatibility with other resin components and being able to dissolve without mixing with a high boiling point solvent that may remain in the dry film even after drying, the transparent curable resin layer 23a more preferably contains a high molecular weight epoxy resin having a weight average molecular weight of 10,000 to 35,000.

[0094] The transparent curable resin layer 23a has an appropriate viscosity when heated because it contains a high molecular weight epoxy resin with a weight average molecular weight of 10,000 to 100,000 as the epoxy resin. As a result, the storage modulus of the transparent curable resin layer 23a in the range of 100°C to 150°C can be adjusted to a preferred range. As the high molecular weight epoxy resin used in the transparent curable resin layer 23a, a phenoxy type epoxy resin that has good compatibility with other epoxy resins is preferable.

[0095] Among epoxy resins, the phenoxy type epoxy resin has a relatively large molecular weight and has a suitable viscosity when heated. Therefore, the storage modulus of the transparent curable resin layer 23a in the range of 100°C to 150°C can be adjusted to a preferred range. Moreover, unlike other thermoplastic resins such as polyester, the phenoxy type epoxy resin can be cured as an epoxy resin. Therefore, the crosslink density can be increased, and the heat resistance of the cured product and the reliability of performance for long-term use are not impaired. From the viewpoint of ensuring a storage modulus that presses the black curable resin layer 22a during thermocompression bonding, the glass transition temperature of the phenoxy type epoxy resin used in the transparent curable resin layer 23a is preferably 100°C or higher.

[0096] Specific examples of phenoxy type epoxy resins include "1256", "YX7200", "YX8100", and "YX7180" manufactured by Mitsubishi Chemical Corporation, "YP-50", "YP-50S", and "YP-70" manufactured by Nippon Steel Chemical & Material Co., Ltd., "N-690" manufactured by DIC Corporation, and "H-157" and "EXA-192" manufactured by DIC Corporation.

[0097] The amount of the high molecular weight epoxy resin in the transparent curable resin layer 23a is preferably 30 to 80% by mass, more preferably 40 to 70% by mass, and even more preferably 45 to 60% by mass, based on 100% by mass of the total resin solid content of the transparent curable resin layer 23a. The same is true for the preferred amount of the phenoxy type epoxy resin in the transparent curable resin layer 23a. When the amount is within the above range, it is possible to control the storage modulus, and it is possible to ensure a storage modulus sufficient to press the black curable resin layer 22a during thermocompression bonding. In addition, it is possible to suppress flow during thermosetting, suppressing appearance defects after curing such as repelling, and further, it is difficult to cause problems when performing etching treatment in a later process. In addition, toughness is improved, and crack-like defects are less likely to occur during thermocompression bonding. In addition, when it is equal to or less than the above upper limit, it is possible to increase the crosslink density of the transparent resin layer 23 in the cured state, and improve heat resistance and chemical resistance.

[0098] Furthermore, the epoxy resin used in the transparent curable resin layer 23a is preferably a polyfunctional epoxy resin. By including a polyfunctional epoxy resin in the transparent curable resin layer 23a, the crosslink density can be increased, the stability of the performance of the cured product of the epoxy resin composition for long-term use can be further improved, and the heat resistance can also be improved. In addition, the polyfunctional epoxy resin has a lower viscosity in the range of 100°C to 150°C than the phenoxy type epoxy resin. Therefore, by combining a polyfunctional epoxy resin with a phenoxy type epoxy resin, the storage modulus of the transparent curable resin layer 23a can be easily adjusted.

[0099] Specific examples of polyfunctional epoxy resins include "YX7700", "157S70", and "1032S60" manufactured by Mitsubishi Chemical Corporation, "NC7000L", "XD1000", and "EOCN-1020" manufactured by Nippon Kayaku Co., Ltd., "ESN485" manufactured by Nippon Steel Chemical & Material Co., Ltd., and "N-690", "N-695", and "HP-7200H" manufactured by DIC Corporation.

[0100] The amount of the polyfunctional epoxy resin in the transparent curable resin layer 23a is preferably 90% by mass or less, more preferably 10 to 80% by mass, and even more preferably 25 to 60% by mass, based on 100% by mass of the total resin solid content of the transparent curable resin layer 23a. Within the above range, the storage modulus of the transparent curable resin layer 23a during thermocompression bonding can be controlled, and the heat resistance and chemical resistance after curing can be improved.

[0101] From the viewpoint of ensuring sufficient fluidity during thermocompression bonding, the transparent curable resin layer 23a preferably contains an epoxy resin having a softening point or melting point of 120° C. or less. To improve handleability and heat resistance of the cured product, the transparent curable resin layer 23a more preferably contains an epoxy resin having a softening point or melting point of 50 to 105° C. The transparent curable resin layer 23a contains an epoxy resin having a softening point or melting point within the above range, which makes it possible to control the storage modulus.

[0102] The total amount of epoxy resin in the transparent curable resin layer 23a is preferably 10 to 100% by mass, more preferably 30 to 99% by mass, and even more preferably 50 to 95% by mass, based on 100% by mass of the total resin solid content of the transparent curable resin layer 23a. Within the above range, the storage modulus can be controlled, and the storage modulus for pressing the black curable resin layer 22a during thermocompression bonding can be ensured. Furthermore, within the above range, the flow of the transparent curable resin layer 23a during thermal curing can be suppressed, and poor appearance after curing such as repelling can be suppressed, and further, problems are less likely to occur when etching is performed in a later process. Furthermore, if the amount is equal to or greater than the above lower limit, the heat resistance of the transparent curable resin layer 23a after curing is further improved.

[0103] (Elastomer) The transparent curable resin layer 23a preferably contains an elastomer in addition to a resin such as an epoxy resin. The transparent curable resin layer 23a contains an elastomer, which makes it easy to control the storage modulus. The elastomer may be the same as that of the black curable resin layer 22a. Among them, NBR is more preferable. NBR has good compatibility with epoxy resin. As a result, the storage modulus of the transparent curable resin layer 23a at about 150°C can be increased, and the adhesion between the transparent curable resin layer 23a and the black curable resin layer 22a can be improved. The preferable weight average molecular weight of the elastomer is the same as that of the black curable resin layer 22a.

[0104] In particular, when the transparent curable resin layer 23a is composed of an epoxy resin composition, it preferably contains a modified elastomer having a functional group capable of reacting with an epoxy group. The modified elastomer having a functional group capable of reacting with an epoxy group also acts as a curing agent for the epoxy resin. In addition, the modified elastomer can react with and bond to the epoxy resin. This improves the heat resistance and reliability against thermal shock of the transparent resin layer 23. Furthermore, the difference in polarity between the functional group capable of reacting with the epoxy resin and the resin skeleton has a favorable effect on dispersibility, and when carbon black is contained in the transparent curable resin layer 23a, good dispersibility is obtained.

[0105] Examples of functional groups capable of reacting with epoxy groups include those of the black curable resin layer 22a. Among them, acid groups or acid anhydride groups, which can be cured at low temperatures and can ensure a long working time, are preferred, and carboxy groups or carboxylic anhydride groups are more preferred.

[0106] When the transparent curable resin layer 23a is made of an epoxy resin composition, it preferably contains modified NBR having a carboxy group. The modified NBR having a carboxy group may be the same as that of the black curable resin layer 22a. Two or more types of modified elastomers having a functional group capable of reacting with an epoxy group may be used in combination.

[0107] The blending amount of the elastomer in the transparent curable resin layer 23a is preferably 0 to 50% by mass, more preferably 1 to 70% by mass, and even more preferably 5 to 50% by mass, based on 100% by mass of the total resin solid content of the transparent curable resin layer 23a. Within the above range, the storage modulus of the transparent curable resin layer 23a can be controlled. Furthermore, when it is equal to or less than the above upper limit, it is possible to ensure a storage modulus that presses the black curable resin layer 22a during thermocompression bonding. Furthermore, it is possible to suppress flow during thermal curing, suppressing appearance defects after curing such as repelling, and furthermore, it is difficult to cause problems when performing etching treatment in a later process. Furthermore, when it is equal to or more than the above lower limit, the dispersibility of carbon black is improved. Furthermore, the film-forming property is improved, and the distribution of film thickness when the epoxy resin composition is applied to form a film can be narrowed.

[0108] (hardening agent) When the transparent curable resin layer 23a is made of an epoxy resin composition, it preferably contains a curing agent for an epoxy resin other than the modified elastomer having a functional group capable of reacting with an epoxy group. Examples of the other curing agent include the same curing agent as that for the black curable resin layer 22a. Two or more types of the other curing agents may be used in combination.

[0109] (curing catalyst) When the transparent curable resin layer 23a is made of an epoxy resin composition, it preferably contains a curing catalyst that accelerates the curing reaction of the epoxy resin. Examples of the curing catalyst include the same curing catalysts as those for the black curable resin layer 22a, and the preferred embodiments are also the same.

[0110] The amount of the curing catalyst is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 4 parts by mass, and even more preferably 0.1 to 3 parts by mass, relative to 100 parts by mass of the total resin solid content of the transparent curable resin layer 23a. Within the above range, curing can be sufficiently promoted and the pot life of the curable resin layer 21a can be secured. Two or more types of curing catalysts may be used in combination.

[0111] (Other Ingredients) The transparent curable resin layer 23a may contain a black pigment or black dye in order to suppress uneven light emission or color unevenness.

[0112] When the transparent curable resin layer 23a contains carbon black from the viewpoint of increasing the total light transmittance, the amount of carbon black is preferably less than 5 parts by mass, more preferably 1 part by mass or less, and even more preferably 0.1 part by mass or less, relative to 100 parts by mass of the total resin solid content. The transparent curable resin layer 23a may further contain, as necessary, a resin other than the epoxy resin and the elastomer, a thickener, a defoamer and / or a leveling agent, an adhesion imparting agent such as a coupling agent, and a flame retardant.

[0113] (Storage modulus) The storage modulus of the transparent curable resin layer 23a in an uncured state is preferably greater than the storage modulus of the black curable resin layer 22a in an uncured state. At 100° C., the storage modulus of the transparent curable resin layer 23a in an uncured state is preferably greater than the storage modulus of the black curable resin layer 22a in an uncured state. At 150° C., the storage modulus of the transparent curable resin layer 23a in an uncured state is preferably greater than the storage modulus of the black curable resin layer 22a in an uncured state.

[0114] The storage modulus of the transparent curable resin layer 23a in an uncured state is preferably greater than the storage modulus of the black curable resin layer 22a in an uncured state at 100° C. to 150° C. If the storage modulus of the transparent curable resin layer 23a in an uncured state is greater than the storage modulus of the black curable resin layer 22a in an uncured state at 100° C. and 150° C., the storage modulus of the transparent curable resin layer 23a in an uncured state is usually greater than the storage modulus of the black curable resin layer 22a in an uncured state over the entire range of 100° C. to 150° C.

[0115] The storage modulus of the transparent curable resin layer 23a in an uncured state at 100° C. is preferably 1.0×10 7 Pa or less, more preferably 1.0×10 3 Pa or more 1.0×10 7 Pa or less, and even more preferably 5.0×10 4 Pa or more 5.0×10 6 Pa or less.

[0116] In an uncured state, the transparent curable resin layer 23a has a storage modulus at 100°C equal to or less than a preferred upper limit, so that sufficient fluidity is obtained without impeding the flow of the black curable resin layer 22a when it is pressure-bonded to the element-mounted substrate 12. As a result, the black curable resin layer 22a can follow the unevenness of the element-mounted substrate 12 caused by the plurality of light-emitting elements 11 and sufficiently fill the gaps between the plurality of light-emitting elements 11.

[0117] In an uncured state, the storage modulus of the transparent curable resin layer 23a at 100°C is equal to or greater than the preferred lower limit, so that the fluidity of the transparent curable resin layer 23a is suppressed, and the surface of the transparent curable resin layer 23a can be made smoother after thermocompression bonding to match the light emitting element 11. As a result, the appearance can be improved, and appearance defects such as repelling are less likely to occur during thermal curing.

[0118] In an uncured state, the storage modulus of the transparent curable resin layer 23a at 150° C. is preferably 1.0×10 4 Pa or more, more preferably 1.0×104 ~5.0×10 7 Pa, and even more preferably 1.0×10 5 ~5.0×10 6 Pa. In an uncured state, the storage modulus of the transparent curable resin layer 23a at 150°C is equal to or less than the preferred upper limit, so that cracks due to cure shrinkage are less likely to occur during thermal curing. In an uncured state, the storage modulus of the transparent curable resin layer 23a at 150°C is equal to or more than the preferred lower limit, so that flow of the transparent curable resin layer 23a during thermal curing can be suppressed, and defects in appearance after curing, such as repelling, can be suppressed. Furthermore, problems are less likely to occur when performing an etching process in a later step.

[0119] In an uncured state, the storage modulus of the transparent curable resin layer 23a at 100° C. is preferably 10 to 1000 times, more preferably 30 to 500 times, that of the black curable resin layer 22a. In an uncured state, the storage modulus of the transparent curable resin layer 23a at 150° C. is preferably 5 to 10000 times, more preferably 10 to 1000 times, that of the black curable resin layer 22a. When the storage modulus of the transparent curable resin layer 23a is higher than that of the black curable resin layer 22a at 100° C. and 150° C., the storage modulus of the transparent curable resin layer 23a is usually higher than that of the black curable resin layer 22a in the entire range of 100° C. to 150° C.

[0120] (3) Protective sheet The protective sheets 25 and 26 have a role of protecting the curable resin layer 21a, and can also be used as sheets onto which a coating liquid of a curable resin composition is applied when the encapsulating sheet 20 is formed.

[0121] Examples of the protective sheets 25, 26 that can be used include polyester films such as polyethylene terephthalate and polyethylene naphthalate, films made of thermoplastic resins such as polyimide films, polyamideimide films, polyethylene films, polytetrafluoroethylene films, polypropylene films, and polystyrene films, as well as surface-treated paper.

[0122] Among these, polyester film is preferably used from the viewpoints of heat resistance, mechanical strength, ease of handling, etc. The thickness of the protective sheets 25, 26 is not particularly limited and is appropriately selected within the range of about 10 to 150 μm depending on the application. The surfaces of the protective sheets 25, 26 to which the curable resin composition is applied may be subjected to a release treatment.

[0123] 3. Manufacturing method of light-emitting electronic components Next, a method for manufacturing a light-emitting electronic component will be described.

[0124] The manufacturing method of the light-emitting electronic component according to this embodiment includes the steps of contacting the curable resin layer 21a, which is in an uncured state of the resin layer 21, with the plurality of light-emitting elements 11, filling a portion of the curable resin layer 21a between the plurality of light-emitting elements 11 by press bonding, curing the curable resin layer 21a after press bonding, and covering the gaps 40 between the element-mounted substrates 12 and the two or more resin layers 21 with a covering layer 30 from above the two or more cured resin layers 21.

[0125] Fig. 3 shows a flow of main manufacturing steps of a light-emitting electronic component according to one embodiment. Fig. 4 shows a cross-sectional view of an early stage of the flow of Fig. 3. Fig. 5 shows a cross-sectional view of a middle stage of the process following Fig. 4. Fig. 6 shows a cross-sectional view of a later stage of the process following Fig. 5. Hereinafter, a method for manufacturing a light-emitting electronic component according to one embodiment will be described with reference to Figs. 3 to 6.

[0126] The method for manufacturing a light-emitting electronic component according to this embodiment preferably includes a preparing step (S110), a contacting step (S120), a filling step (S130), a curing step (S140), an arranging step (S150), and a covering step (S160).

[0127] (1) Preparation process (S110) The preparation step is a step of preparing a curable resin layer 21a in a pre-cured state of the resin layer 21. Specifically, as shown in Fig. 4(4A), an encapsulating sheet 20 is prepared.

[0128] (2) Contact process (S120) The contact step is a step of contacting the curable resin layer 21a onto the plurality of light-emitting elements 11. Specifically, as shown in (4B) and (4C) of Fig. 4, the protective sheet 25 of the encapsulating sheet 20 is peeled off to expose the black curable resin layer 22a and bring it into contact with the upper surfaces of the plurality of light-emitting elements 11.

[0129] (3) Filling process (S130) The filling step is a step of filling a part of the curable resin layer 21a (mainly the black curable resin layer 22a) between the plurality of light emitting elements 11 by press bonding. In the press bonding, heat is preferably also applied. For this reason, the press bonding may be called thermocompression bonding. Specifically, as shown in FIG. 5 (5A), the black curable resin layer 22a and a part of the transparent curable resin layer 23a of the encapsulating sheet 20 are embedded between the light emitting elements 11 by thermocompression bonding. At this time, if the storage modulus of the black curable resin layer 22a is relatively low and the fluidity of the layer 22a is ensured, the black curable resin layer 22a is likely to be filled between the light emitting elements 11 while following the unevenness formed by the plurality of light emitting elements 11. In addition, the black curable resin layer 22a is unlikely to remain on the light emitting elements 11.

[0130] The temperature in thermocompression bonding is preferably 80 to 120° C., and more preferably 90 to 110° C. By setting the temperature in thermocompression bonding to 80° C. or higher, the fluidity of the curable resin layer 21a is easily ensured. Furthermore, by setting the temperature in thermocompression bonding to 120° C. or lower, damage to the light emitting element 11 is unlikely to occur. By setting the temperature in thermocompression bonding to 90 to 110° C., the fluidity can be controlled more precisely, and the occurrence of unevenness or crack-like defects can be suppressed.

[0131] The pressure in the thermocompression bonding is preferably 0.05 to 1.0 MPa, and more preferably 0.1 to 0.5 MPa. By setting the pressure in the thermocompression bonding to be equal to or greater than the preferred lower limit, the black curable resin layer 22a is unlikely to remain on the light emitting element 11, and the light from the light emitting element 11 is not prevented from reaching the viewer. Furthermore, by setting the pressure in the thermocompression bonding to be equal to or less than the preferred upper limit, the light emitting element 11 is unlikely to be damaged. The thermocompression bonding is preferably performed using a vacuum press machine capable of molding in a vacuum state. This makes it easier to avoid defects that may occur due to air being mixed into the obtained light emitting electronic component 1.

[0132] (4) Curing process (S140) The curing step is a step of curing the curable resin layer 21a after the press bonding. Specifically, after the filling step is completed, the protective sheet 26 is peeled off. Then, the curable resin layer 21a is cured (see (5B) of FIG. 5). As a result, a resin layer-element-mounted substrate 50, which is the element-mounted substrate 12 sealed with the resin layer 21, is completed.

[0133] The curing temperature is preferably 100 to 160° C., and more preferably 110 to 150° C. By setting the curing temperature to 100° C. or higher, the curable resin layer 21a can be cured reliably. By setting the curing temperature to 110° C. or higher, the curing time of the curable resin layer 21a can be shortened. Furthermore, by setting the curing temperature to the above upper limit temperature or lower, the light emitting element 11 is less likely to be damaged.

[0134] The curing time varies depending on the curing temperature, but is preferably 30 to 360 minutes, and more preferably 45 to 180 minutes. If the storage modulus of the transparent curable resin layer 23a is relatively high and the fluidity of the layer 23a is suppressed, poor appearance after curing is suppressed.

[0135] (5) Arrangement step (S150) The arrangement process is a process of arranging a plurality of resin layer-element-mounted substrates 50 in accordance with the size of the display. The resin layer-element-mounted substrates 50 are preferably arranged in a rectangular region with m substrates vertically and n substrates horizontally. Here, m and n are integers of 1 or more, and preferably integers of 2 or more, provided that neither of them is 1. FIG. 6 (6A) shows a vertical cross-sectional view of only a portion of the plurality of resin layer-element-mounted substrates 50 arranged. When the plurality of resin layer-element-mounted substrates 50 are arranged, there are gaps 40 between the resin layer-element-mounted substrates 50.

[0136] (6) Covering process (S160) The covering step is a step of covering the gaps 40 between the element-mounted substrates 12 and the two or more resin layers 21 with a covering layer 30 from above the two or more cured resin layers 21. Specifically, as shown in FIG. 6 (6B), the covering layer 30 is preferably attached to the upper surfaces of the multiple transparent resin layers 23 by an adhesive layer 31. This step causes the covering layer 30 to cover the top of the gaps 40. Therefore, a user looking from the display side arranged above the covering layer 30 can hardly or not at all see the gaps 40. When the covering layer 30 is a translucent layer, the gaps 40 cannot be seen in particular.

[0137] An example of a method for forming the hard coat layer 33 on the surface of the support film 32 is to apply a coating agent for the hard coat layer 33 to the surface of the support film 32 and then harden the coating agent. Examples of methods for applying the coating agent include various coaters such as a die coater, gravure coater, roll coater, curtain flow coater, spin coater, bar coater, reverse coater, kiss coater, fountain coater, rod coater, air doctor coater, knife coater, blade coater, cast coater, and screen coater. Examples of methods for hardening the coating agent include heat hardening, ultraviolet hardening, and electron beam hardening.

[0138] Through the above steps, the light-emitting electronic component 1 is completed. [Industrial Applicability]

[0139] The light-emitting electronic component according to the present invention can be used, for example, as a light-emitting device disposed on the back side of a display. [Explanation of symbols]

[0140] DESCRIPTION OF SYMBOLS 1...light-emitting electronic component, 10...substrate, 11...light-emitting element, 12...substrate with element, 20...encapsulating sheet, 21...resin layer, 21...curable resin layer, 22...black resin layer (an example of a first resin layer), 22a...black curable resin layer (an example of a curable first resin layer), 23...transparent resin layer (an example of a second resin layer), 23a...transparent curable resin layer (an example of a curable second resin layer), 30...covering layer, 32...support film, 33...hard coat layer, 40...gap.

Claims

1. Two or more element-mounted substrates each having a plurality of light-emitting elements disposed on the substrate; a resin layer that is pressure-bonded to a substrate surface from above the plurality of light-emitting elements in each of the element-mounted substrates; a covering layer that covers the gaps between the element-mounted substrates and the two or more resin layers from above the two or more resin layers; Equipped with The light-emitting electronic component is characterized in that the resin layer is a layer capable of transmitting light from the light-emitting element.

2. The light-emitting electronic component according to claim 1, characterized in that the resin layers are laminated in the following order from the side closest to the substrate: a first resin layer, and a second resin layer having higher light transmittance than the first resin layer.

3. 2. The light-emitting electronic component according to claim 1, wherein the covering layer comprises a hard coat layer on the surface of a support film.

4. The light-emitting electronic component according to claim 1 , wherein the first resin layer contains a black pigment or dye.

5. A method for producing a light-emitting electronic component according to any one of claims 1 to 4, comprising the steps of: contacting the curable resin layer, in an uncured state, on the plurality of light-emitting elements; filling a portion of the curable resin layer between the plurality of light-emitting elements by pressing; A step of curing the curable resin layer after the press bonding; covering the gaps between the element-mounted substrates and the two or more resin layers with the covering layer from above the two or more cured resin layers; A method for producing a light-emitting electronic component comprising the steps of:

Images