Method for manufacturing MIP element

Abstract

To provide a method for manufacturing an MIP element which can prevent a micro LED from being buried in an adhesive layer.SOLUTION: A method for manufacturing an MIP element 1 in which a plurality of micro LEDs 11, 12 and 13 are integrated with each other includes the steps of: press-fitting an integrated sealing sheet 2 in which a black curable resin layer, a transparent curable resin layer and a protective layer 25 are laminated in this order to the plurality of micro LEDs so as to bring a surface on the black curable resin layer side into contact with a side of a light-emitting surface 14; filling the plurality of micro LEDs with at least the black curable resin layer out of the black curable resin layer and the transparent curable resin layer; curing the black curable resin layer and the transparent curable resin layer and forming a black resin layer 30 and a transparent resin layer 31; and separating a fourth substrate from an electrode, and exposing the electrode to outside of the black resin layer obtained by curing the black curable resin layer.SELECTED DRAWING: Figure 14

Description

[Technical field]

[0001] The present invention relates to a method for producing an MIP element. [Background technology]

[0002] Light-emitting diodes (LEDs) have been trending toward miniaturization in recent years, as seen in mini LEDs and micro LEDs. When LEDs are used in displays, it is expected that by making the light-emitting unit smaller, higher definition, higher resolution, and improved image quality will be achieved. Meanwhile, the size of displays is tending to become larger than conventional displays. However, arranging many micro LEDs individually on a circuit board to fit a large display requires advanced technology and high manufacturing costs.

[0003] As a method to solve these problems, MIP (MicroLED in Package) elements, which fix multiple micro LEDs to a small substrate, have been devised. Since MIP elements contain multiple micro LEDs on a single substrate, it is easier to place MIP elements on a circuit board than to place individual micro LEDs on a substrate. As a result, it is expected that the cost of using LEDs in large displays will be reduced.

[0004] As a method for producing an MIP element, for example, the method described in Patent Document 1 has been conventionally known. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Chinese Patent Application Publication No. 113257964A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the conventional manufacturing method disclosed in the above Patent Document 1 requires a long time for manufacturing and is complicated since it includes multiple steps of transferring to the substrate, etching, and polishing the substrate.

[0007] In view of the above problems, the present inventors have found, prior to the present invention, a method for manufacturing an MIP element, in which an integrated encapsulating sheet, in which two or more curable resin layers including a light-shielding layer are laminated on one end of a film substrate, is pressure-bonded and cured to a micro LED transferred from a formation substrate to an auxiliary substrate. The inventors have found that by pressure-bonding and curing the sheet to the micro LED, an etching process for the light-shielding layer after formation is unnecessary, and an MIP element can be manufactured more simply and in a shorter time.

[0008] However, it was found that the technology developed prior to the present invention also required further improvement. During transportation, the micro LED is separated from the formation substrate by laser lift-off technology and fixed to the adhesive layer on the auxiliary substrate. When the micro LED is separated from the formation substrate, a large amount of energy is applied by the laser light, and it accelerates and reaches the auxiliary substrate, so it is exposed to impact and may be damaged. Therefore, a flexible adhesive layer with cushioning properties is used to mitigate the impact. However, the adhesive layer was so flexible that it sometimes caused the micro LED to be buried when the integrated encapsulating sheet was pressed.

[0009] The present invention has been made to solve the above problems, and aims to provide a manufacturing method for a MIP element that can prevent a micro LED from being buried in an adhesive layer. [Means for solving the problem]

[0010] (1) A method for producing an MIP element according to one embodiment for achieving the above object comprises the steps of: A method for manufacturing a MIP device integrating a plurality of micro LEDs, comprising the steps of: Fixing the light emitting surface side of the plurality of micro LEDs on a first substrate; A step of fixing electrodes located on a surface opposite to the light emitting surface of the plurality of micro LEDs to a first electrode adhesive layer on a second substrate, the first electrode adhesive layer having a cushioning property capable of absorbing an impact when the first substrate is separated from the light emitting surface; separating the first substrate from the light emitting surface; Fixing the light emitting surfaces of the plurality of micro LEDs to a light emitting surface adhesive layer on a third substrate; separating the second substrate from the electrode; Fixing the electrodes of the plurality of micro LEDs to a second electrode adhesive layer on a fourth substrate, the second electrode adhesive layer having a higher hardness than the first electrode adhesive layer; separating the third substrate from the light emitting surface; A step of pressing an integrated encapsulating sheet having a black curable resin layer, a transparent curable resin layer, and a protective layer laminated in this order onto the plurality of micro LEDs such that the surface of the black curable resin layer is in contact with the light emitting surface; Filling at least the black curable resin layer between the micro LEDs; and curing the black curable resin layer and the transparent curable resin layer; and separating the fourth substrate from the electrodes to expose the electrodes to the outside of the cured black curable resin layer. (2) A method for producing an MIP element according to another embodiment includes the steps of: A method for manufacturing a MIP device integrating a plurality of micro LEDs, comprising the steps of: Fixing the light emitting surface side of the plurality of micro LEDs on a first substrate; A step of bringing a first electrode adhesive layer, which is an adhesive layer on a second substrate and has a cushioning property capable of absorbing an impact when the first substrate is separated from the light emitting surface, close to an electrode located on a surface opposite to the light emitting surface of the plurality of micro LEDs, separating the light emitting surface from the first substrate and fixing the plurality of micro LEDs to the first electrode adhesive layer of the second substrate; Fixing the light emitting surfaces of the plurality of micro LEDs to a light emitting surface adhesive layer on a third substrate; separating the second substrate from the electrode; Fixing the electrodes of the plurality of micro LEDs to a second electrode adhesive layer on a fourth substrate, the second electrode adhesive layer having a higher hardness than the first electrode adhesive layer; separating the third substrate from the light emitting surface; A step of pressing an integrated encapsulating sheet having a black curable resin layer, a transparent curable resin layer, and a protective layer laminated in this order onto the plurality of micro LEDs such that the surface of the black curable resin layer is in contact with the light emitting surface; Filling at least the black curable resin layer between the micro LEDs; and curing the black curable resin layer and the transparent curable resin layer; and separating the fourth substrate from the electrodes to expose the electrodes to the outside of the cured black curable resin layer. (3) In another embodiment of the manufacturing method of an MIP element, the method may further include a step of forming a conductive layer on the electrode after separation from the second electrode adhesive layer on the fourth substrate, which enables current to be applied to the micro LED from the outside. (4) In the method for manufacturing an MIP element according to another embodiment, preferably, three micro LEDs are provided, and each of the micro LEDs may be an LED emitting red, green and blue light. (5) In another embodiment of the method for manufacturing an MIP element, preferably, the height of the black resin layer obtained by curing the black curable resin layer is 0.1 to 0.9 times the height of the multiple micro LEDs, and the height of the transparent resin layer obtained by curing the transparent curable resin layer is 0.1 to 5.0 times the height of the multiple micro LEDs. (6) In the method for producing an MIP element according to another embodiment, the protective layer may preferably be a glass layer. (7) In the method for producing an MIP element according to another embodiment, the glass layer may preferably have a thickness of 30 to 70 μm. (8) In the method for producing an MIP element according to another embodiment, the protective layer may preferably be a resin layer. (9) In the method for producing an MIP element according to another embodiment, the resin layer may preferably be a layer obtained by laminating at least a hard coat layer that protects the MIP element and a support film layer that supports the hard coat layer. Effect of the Invention

[0011] According to the present invention, a manufacturing method of a MIP element capable of preventing a micro LED from being buried in an adhesive layer can be provided. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 shows a cross-sectional view of an integrated encapsulating sheet used in a manufacturing method according to one embodiment, cut along its thickness direction. [Diagram 2] FIG. 2 shows a cross-sectional view taken in the same manner as FIG. 1 of another integrated encapsulating sheet used in a manufacturing method according to an embodiment. [Diagram 3] FIG. 3 shows a flow diagram of a manufacturing method according to one embodiment. [Figure 4] FIG. 4 is a cross-sectional view that illustrates a schematic state after the first fixing step in the manufacturing method according to one embodiment. [Diagram 5] FIG. 5 is a cross-sectional view that illustrates a schematic state after the second fixing step in the manufacturing method according to one embodiment. [Figure 6] FIG. 6 is a cross-sectional view that illustrates a schematic state after the first separation step in the manufacturing method according to one embodiment. [Figure 7] FIG. 7 is a cross-sectional view that illustrates a schematic state after the third fixing step in the manufacturing method according to one embodiment. [Figure 8] FIG. 8 is a cross-sectional view that illustrates a schematic state after the second separation step in the manufacturing method according to one embodiment. [Figure 9] FIG. 9 is a cross-sectional view that illustrates a schematic state after the fourth fixing step in the manufacturing method according to one embodiment. [Figure 10]FIG. 10 is a cross-sectional view that illustrates a schematic state after the third separation step in the manufacturing method according to one embodiment. [Figure 11] FIG. 11 is a cross-sectional view that shows a schematic state after the compression bonding step in the manufacturing method according to one embodiment. [Figure 12] FIG. 12 is a cross-sectional view that illustrates a schematic state after the filling step in the manufacturing method according to one embodiment. [Figure 13] FIG. 13 is a cross-sectional view that illustrates a schematic state after the curing step in the manufacturing method according to one embodiment. [Figure 14] FIG. 14 is a cross-sectional view that shows a schematic representation of the state after the fourth separation step in the manufacturing method according to one embodiment, that is, the MIP element. [Figure 15] FIG. 15 shows a flow diagram of a manufacturing method according to another embodiment. [Figure 16] FIG. 16 is a cross-sectional view showing a schematic state before and after a moving step in a manufacturing method according to another embodiment. [Figure 17] FIG. 17 shows a flow diagram of a manufacturing method according to another embodiment. [Figure 18] FIG. 18 is a cross-sectional view that illustrates a schematic state after a conductive layer forming step in a manufacturing method according to another embodiment. 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 addition, in this specification and claims, a numerical range expressed by "~" means a numerical range with the numerical values ​​before and after ~ as the lower and upper limits.

[0014] 1. Integrated encapsulating sheet First, the integrated encapsulating sheet 2 used in the manufacturing method according to the present embodiment will be described. FIG. 1 shows a cross-sectional view of the integrated encapsulating sheet used in the manufacturing method according to one embodiment when cut along its thickness direction. The integrated encapsulating sheet 2 is a laminate in which a black curable resin layer 20, a transparent curable resin layer 21, and a protective layer 25 are laminated in this order. In the integrated encapsulating sheet 2, the surface of the black curable resin layer 20 is pressure-bonded to the light-emitting surface 14 of the micro LEDs 11, 12, and 13 during a pressure-bonding process described later. In addition, the black curable resin layer 20 and the transparent curable resin layer 21 are in an uncured state until a curing process described later is performed. That is, the black curable resin layer 20 and the transparent curable resin layer 21 are cured by the curing process to become the black resin layer 30 and the transparent resin layer 31, respectively. Hereinafter, each layer constituting the integrated encapsulating sheet 2 will be described.

[0015] (1) Black curable resin layer The black curable resin layer 20 is a layer for blocking light between the micro LEDs 11, 12, and 13 and improving the contrast of the display. The black curable resin layer 20 is filled between the multiple micro LEDs 11, 12, and 13 fixed on the second substrate 60 in a compression process represented by thermocompression bonding. The black curable resin layer 20 is also a layer for preventing poor appearance due to expansion of gaps between the micro LEDs 11, 12, and 13 due to a curing process represented by thermosetting, and damage to the micro LEDs 11, 12, and 13 due to external factors in a later process.

[0016] [Lab value] The Lab values ​​of the black curable resin layer 20 in a cured state measured in accordance with JIS Z 8722 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 cured state are within the preferred ranges, the black curable resin layer 20 can block light between the micro LEDs 11, 12, and 13 after curing, thereby further improving the contrast of the display.

[0017] [Total light transmittance] The total light transmittance of the black curable resin layer 20 in a cured state is lower than that of the transparent curable resin layer 21 in a cured state. Specifically, the black curable resin layer 20 is prepared so that the total light transmittance of the black curable resin layer 20 in a cured state is 0 to 50%. The total light transmittance of the black curable resin layer 20 in a cured state is preferably prepared so that the total light transmittance is 0 to 40%, more preferably 0 to 30%. When the total light transmittance is equal to or less than the upper limit value such as 50%, 40%, or 30%, the black curable resin layer 20 can realize light shielding between the micro LEDs 11, 12, and 13 after curing. The total light transmittance in this specification can be measured by a haze meter in accordance with JIS K 7136. The total light transmittance in a cured state can be changed mainly by the presence or absence of carbon black or the amount of carbon black. The total light transmittance in a cured state can also be changed by the thickness of the black curable resin layer 20 and the type of resin composition.

[0018] [Storage modulus] The storage modulus of the black curable resin layer 20 in an uncured state is preferably smaller than the storage modulus of the transparent curable resin layer 21 in an uncured state. The storage modulus of the black curable resin layer 20 in an uncured state at 100° C. 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 4Pa or less. In an uncured state, the storage modulus of the black curable resin layer 20 at 100°C is a preferred upper limit or less, so that the black curable resin layer 20 exhibits sufficient fluidity when pressed onto the micro LEDs 11, 12, and 13, and can sufficiently fill the gaps between the micro LEDs 11, 12, and 13. In an uncured state, the storage modulus of the black curable resin layer 20 at 100°C is a preferred lower limit or more, so that pressure bias during thermocompression of the black curable resin layer 20 and the transparent curable resin layer 21 can be prevented, and a uniform appearance can be maintained. In addition, the outflow of the resin outside a predetermined range can be prevented, and the film thickness after pressing can be secured.

[0019] The storage modulus of the black curable resin layer 20 at 60° C. after heat treatment at 120° C. for 1 hour is preferably 7×10 8 Pa or more 2×10 10 Pa or less. When the storage modulus is equal to or less than the preferred upper limit, it is possible to prevent cracks from occurring in the cured black curable resin layer 20 when the edge of the MIP element 1 is cut. When the storage modulus is equal to or more than the preferred lower limit, it is possible to prevent the cured black curable resin layer 20 from deforming and expanding and contracting when the edge of the MIP element 1 is cut, and to prevent the integrated encapsulating sheet 2 on the edge side of the MIP element 1 from becoming wavy.

[0020] [Curable resin composition] The black curable resin layer 20 includes a curable resin composition. An example of the curable resin composition is a curable resin composition containing 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 containing an epoxy resin as a main component, or a composition containing an epoxy resin and a curing agent as main components.

[0021] When the black curable resin layer 20 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.

[0022] (Epoxy resin) In the present application, an epoxy resin is a compound having an epoxy group in a molecule. As an epoxy resin, one having two or more epoxy groups in one molecule is preferable. 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.

[0023] 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.

[0024] 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 resin 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, tetraphenyl glycidyl ether ethane, triphenyl glycidyl ether ethane, polyglycidyl ether of sorbitol, and polyglycidyl ether of polyglycerol; glycidyl amine-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.

[0025] Examples of epoxy resins that can be used 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.

[0026] 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.

[0027] Among the above epoxy resins, the epoxy resin used in the black curable resin layer 20 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 more 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 the performance of the cured product of the epoxy resin composition over long-term use, and increases the crosslink density. In addition, the heat resistance of the cured product is also improved.

[0028] 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.

[0029] The blending amount of the polyfunctional epoxy resin in the black curable resin layer 20 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 20. When the blending amount is equal to or more than the lower limit, the crosslinking density can be increased to impart chemical resistance and heat resistance. When the blending 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 20 can be ensured.

[0030] The black curable resin layer 20 preferably does not contain a high molecular weight epoxy resin, or if it contains a high molecular weight epoxy resin, it contains it in a smaller amount than the transparent curable resin layer 21. This makes it easier to ensure sufficient fluidity of the black curable resin layer 20 during thermocompression bonding. The amount of the high molecular weight epoxy resin in the black curable resin layer 20 is preferably less than 50 mass%, more preferably less than 30 mass%, and even more preferably less than 10 mass%, relative to 100 mass% of the total resin solid content of the black curable resin layer 20.

[0031] From the viewpoint of ensuring sufficient fluidity during thermocompression bonding, the black curable resin layer 20 preferably contains an epoxy resin having a softening point or melting point of 100° C. or less. From the viewpoint of handleability and heat resistance of the cured product, the black curable resin layer 20 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 easy to control the storage modulus of the black curable resin layer 20.

[0032] The total amount of epoxy resin in the black curable resin layer 20 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 20. Within the above range, the storage modulus of the black curable resin layer 20 can be easily 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 heat resistance of the black curable resin layer 20 after curing can be improved.

[0033] (Elastomer) The black curable resin layer 20 preferably contains an elastomer in addition to a resin such as an epoxy resin. By containing an elastomer, it becomes easier to control the storage modulus of the black curable resin layer 20, that is, to control the fluidity.

[0034] As the elastomer, a thermosetting elastomer, generally called "rubber", is preferred because it provides excellent heat resistance. Examples of the thermosetting elastomer 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. NBR has good compatibility with epoxy resins, making it easy to control the fluidity of the black curable resin layer 20 at around 100°C, and as a result, the adhesion between the black curable resin layer 20 and the transparent curable resin layer 21 is good.

[0035] The weight average molecular weight of the elastomer is preferably 100,000 to 1,000,000, more preferably 120,000 to 500,000, and even more 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 20 can be easily 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 between the elastomer and the epoxy resin is improved, and the flowability during thermal curing of the black curable resin layer 20 can be more effectively controlled.

[0036] In particular, when the black curable resin layer 20 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, since the modified elastomer can react and bond with the epoxy resin, the heat resistance and reliability against thermal shock after curing of the black curable resin layer 20 are improved. 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 20.

[0037] 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, acid groups and acid anhydride groups are preferred because they can be cured at low temperatures and can ensure a long working life. For the same reason, the functional group is particularly preferably a carboxy group or a carboxylic acid anhydride group.

[0038] That is, when the black curable resin layer 20 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.

[0039] The modified NBR having a carboxy group is preferably a carboxylated acrylonitrile rubber into which acrylic acid, methacrylic acid, maleic anhydride, etc. have been introduced. Commercially available products of the carboxylated acrylonitrile rubber include "NX775" and "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.

[0040] The amount of elastomer in the black curable resin layer 20 is preferably greater than the amount of elastomer in the transparent curable resin layer 21. This allows the storage modulus of the black curable resin layer 20 during thermocompression bonding to be adjusted to an appropriate range lower than that of the transparent curable resin layer 21, and allows flow during thermal curing to be suppressed, when the black curable resin layer 20 contains a large amount of low molecular weight components such as polyfunctional epoxy. As a result, the black curable resin layer 20 can have sufficient flowability during thermocompression bonding and can be prevented from flowing out during thermal curing.

[0041] The amount of the elastomer in the black curable resin layer 20 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 20. Within the above range, the storage modulus of the black curable resin layer 20 can be easily controlled, and appropriate fluidity of the black curable resin layer 20 during thermocompression bonding can be ensured. In addition, when the amount is equal to or greater than the above lower limit, the dispersibility of carbon black in the epoxy resin composition is improved. Furthermore, the film-forming property of the epoxy resin composition is improved, and the film thickness distribution can be narrowed when the epoxy resin composition is applied to form a film.

[0042] (hardening agent) When the black curable resin layer 20 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.

[0043] (curing catalyst) When the black curable resin layer 20 is composed 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 because they are easily soluble in epoxy resins. The blending 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 20. Within the above range, the curing of the black curable resin layer 20 can be sufficiently promoted, and the usable time of the integrated encapsulating sheet 2 can be secured. Two or more types of curing catalysts may be used in combination.

[0044] (Black pigment or black dye) The black curable resin layer 20 is colored black. For coloring, the black curable resin layer 20 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 curable resin layer 20 black, light blocking properties between the multiple micro LEDs 11, 12, and 13 can be achieved.

[0045] The particle size of the carbon black is preferably 10 to 500 nm, more preferably 10 to 300 nm, and even more preferably 10 to 100 nm. The particle size means the average particle size, and can be determined by a measuring device using the dynamic light scattering method. An example of the measuring device using the dynamic light scattering method is NanotracWave II UT151 manufactured by Microtrack Bell.

[0046] 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.

[0047] Among the above carbon blacks, gas black has many surface functional groups and is highly dispersible. It is preferred in that it has high dispersibility and exerts sufficient light-shielding properties even when added in a small amount. In addition, when the black curable resin layer 20 contains a modified elastomer having a functional group capable of reacting with an epoxy resin, the dispersibility is further increased by the interaction between the surface functional group of the gas black and the functional group of the modified elastomer having a functional group capable of reacting with an epoxy resin, and good light-shielding properties and coating liquid stability can be ensured.

[0048] The blending 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 20. When the blending amount of carbon black is equal to or more than the above lower limit, sufficient light blocking properties can be obtained. When the blending amount of carbon black is equal to or less than the above upper limit, the thixotropy of the black curable resin layer 20 is reduced, and the fluidity of the black curable resin layer 20 during thermocompression bonding is increased, so that the black curable resin layer 20 can sufficiently fill the spaces between the multiple micro LEDs 11, 12, and 13.

[0049] (Other Ingredients) The black curable resin layer 20 may contain an inorganic filler to improve flame retardancy and heat resistance and adjust the refractive index. The black curable resin layer 20 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.

[0050] (2)Transparent curable resin layer The transparent curable resin layer 21 is a layer for sufficiently pressing the black curable resin layer 20 between the multiple micro LEDs 11, 12, and 13 fixed on the second substrate 60 in a pressure bonding step described later.

[0051] [Total light transmittance] The total light transmittance of the transparent curable resin layer 21 in a cured state is preferably adjusted to be 30 to 99%, more preferably 35 to 95%, and even more preferably 40 to 90%.

[0052] When the total light transmittance is equal to or greater than the lower limit, even if the transparent curable resin layer 21 in a cured state remains on the micro LEDs 11, 12, and 13, it does not prevent light from reaching the viewer's side.

[0053] [Storage modulus] The storage elastic modulus of the transparent curable resin layer 21 in an uncured state is preferably greater than that of the black curable resin layer 20. Similarly, at 100° C. and 150° C., the storage elastic modulus of the transparent curable resin layer 21 is preferably greater than that of the black curable resin layer 20.

[0054] The storage elastic modulus of the transparent curable resin layer 21 is preferably greater than that of the black curable resin layer 20 at 100 to 150° C. When the storage elastic modulus of the transparent curable resin layer 21 is greater than that of the black curable resin layer 20 at 100° C. and 150° C., the storage elastic modulus of the transparent curable resin layer 21 is usually greater than that of the black curable resin layer 20 over the entire range of 100 to 150° C.

[0055] The storage modulus of the transparent curable resin layer 21 at 100° C. is preferably 1.0×10 3 Pa or more 1.0×10 7 Pa or less, more preferably 5.0×10 3 Pa or more 5.0×10 5 Pa or less.

[0056] Since the storage modulus of the transparent curable resin layer 21 at 100° C. is equal to or less than the preferred upper limit, appropriate flexibility is obtained that does not hinder the flow of the black curable resin layer 20 when it is pressure-bonded to the multiple micro LEDs 11, 12, and 13. In addition, the spaces between the multiple micro LEDs 11, 12, and 13 can be sufficiently filled.

[0057] By making the storage modulus of the transparent curable resin layer 21 at 100°C equal to or greater than the preferred lower limit, the fluidity of the transparent curable resin layer 21 can be suppressed, and the surface of the transparent curable resin layer 21 can be made smoother after thermocompression bonding in accordance with the micro-LEDs 11, 12, and 13. As a result, the appearance can be improved, and appearance defects such as a repellency phenomenon that creates recesses on the layer surface during thermal curing can be prevented from occurring.

[0058] The storage modulus of the transparent curable resin layer 21 at 150° C. is preferably 1.0×10 4Pa or more, more preferably 1.0×10 4 Pa or more 5.0×10 7 Pa or less, and even more preferably 1.0×10 5 Pa or more 5.0×10 6 Pa or less. When the storage modulus of the transparent curable resin layer 21 at 150°C is equal to or less than the preferred upper limit, cracks due to cure shrinkage during thermal curing are less likely to occur. When the storage modulus of the transparent curable resin layer 21 at 150°C is equal to or more than the preferred lower limit, flow during thermal curing of the transparent curable resin layer 21 can be suppressed, and poor appearance after curing, such as a repellency phenomenon, can be suppressed. Furthermore, problems are less likely to occur when etching is performed in a later step.

[0059] The storage elastic modulus of the transparent curable resin layer 21 at 100°C is preferably 10 to 1000 times, more preferably 30 to 500 times, the storage elastic modulus of the black curable resin layer 20. The storage elastic modulus of the transparent curable resin layer 21 at 150°C is preferably 5 to 10000 times, more preferably 10 to 1000 times, the storage elastic modulus of the black curable resin layer 20. When the storage elastic modulus of the transparent curable resin layer 21 is greater than that of the black curable resin layer 20 at 100°C and 150°C, the storage elastic modulus of the transparent curable resin layer 21 is usually greater than that of the black curable resin layer 20 over the entire range of 100 to 150°C.

[0060] The storage modulus of the transparent curable resin layer 21 at 60° C. after heat treatment at 120° C. for 1 hour is preferably 7×10 8 Pa or more 2×10 10 Pa or less. When the storage modulus is equal to or less than the preferred upper limit, it is possible to prevent cracks in the cured transparent curable resin layer 21. When the storage modulus is equal to or more than the preferred lower limit, it is possible to prevent deformation and expansion / contraction of the cured transparent curable resin layer 21. As a result, it is possible to prevent wavy distortion of the integrated encapsulating sheet 2 on the edge side of the MIP element 1.

[0061] [Curable resin composition] The transparent curable resin layer 21 is composed of a curable resin composition. As with the black curable resin layer 20, the curable resin composition may be a curable resin composition containing 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 these, an epoxy resin composition is preferred because it can be cured at low temperatures and has excellent heat resistance and reliability.

[0062] (Epoxy resin) Examples of epoxy resins used in the transparent curable resin layer 21 include the same types as those used in the black curable resin layer 20. From the viewpoint of imparting an appropriate viscosity during compression to the transparent curable resin layer 21, the transparent curable resin layer 21 preferably contains a high molecular weight epoxy resin having a weight average molecular weight of 10,000 to 100,000. In addition, 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 21 more preferably contains a high molecular weight epoxy resin having a weight average molecular weight of 10,000 to 35,000.

[0063] The transparent curable resin layer 21 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. Therefore, the storage modulus of the transparent curable resin layer 21 at 100 to 150° C. can be adjusted to a preferred range. The high molecular weight epoxy resin is preferably a phenoxy type epoxy resin because it has good compatibility with other epoxy resins.

[0064] 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 21 containing the phenoxy type epoxy resin in the range of 100 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 phenoxy type epoxy resin increases the crosslinking density and does not impair the heat resistance of the cured product or the reliability of the performance for long-term use. From the viewpoint of ensuring the storage modulus that presses the black curable resin layer 20 during thermocompression bonding, the glass transition temperature of the phenoxy type epoxy resin used in the transparent curable resin layer 21 is preferably 100°C or higher.

[0065] 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.

[0066] The blending amount of the high molecular weight epoxy resin in the transparent curable resin layer 21 is preferably 30 to 80 mass %, more preferably 40 to 70 mass %, and even more preferably 45 to 60 mass %, relative to 100 mass % of the total resin solid content of the transparent curable resin layer 21. The same is true for the preferred blending amount of the phenoxy type epoxy resin in the transparent curable resin layer 21.

[0067] When the blending amount is within the above range, it becomes easy to control the storage modulus. This ensures a storage modulus that presses the transparent curable resin layer 21 during thermocompression bonding. In addition, flow during thermosetting can be suppressed, and poor appearance after curing such as repellency can be suppressed. Furthermore, problems are less likely to occur when etching is performed in a later process. In addition, toughness is improved, and crack-like defects are less likely to occur during thermocompression bonding. In addition, when the blending amount is equal to or less than the above upper limit, the crosslink density of the transparent curable resin layer 21 in the cured state can be increased, and the heat resistance and chemical resistance can be improved.

[0068] Furthermore, the epoxy resin used in the transparent curable resin layer 21 preferably contains a polyfunctional epoxy resin. The polyfunctional epoxy resin can increase the crosslink density, thereby further improving the stability of the performance of the cured product of the epoxy resin composition over long-term use and improving the heat resistance. In addition, the viscosity of the polyfunctional epoxy resin is lower than that of the phenoxy type epoxy resin in the range of 100 to 150°C. Therefore, the storage modulus of the transparent curable resin layer 21 can be adjusted by combining the polyfunctional epoxy resin with the phenoxy type epoxy resin.

[0069] 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.

[0070] The blending amount of the polyfunctional epoxy resin in the transparent curable resin layer 21 is preferably 90% by mass or less, more preferably 10 to 80% by mass, and even more preferably 25 to 60% by mass, relative to 100% by mass of the total resin solid content of the transparent curable resin layer 21. Within the above range, the storage modulus of the transparent curable resin layer 21 during thermocompression bonding can be controlled, and heat resistance and chemical resistance can be imparted in the cured state.

[0071] From the viewpoint of ensuring sufficient fluidity during thermocompression bonding, the transparent curable resin layer 21 preferably contains an epoxy resin having a softening point or melting point of 120° C. or less, and from the viewpoint of handleability and heat resistance of the cured product, more preferably contains an epoxy resin having a softening point or melting point of 50 to 105° 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.

[0072] The total amount of epoxy resin in the transparent curable resin layer 21 is preferably 10 to 100% by mass, more preferably 30 to 99% by mass, and even more preferably 50 to 95% by mass, relative to 100% by mass of the total resin solid content of the transparent curable resin layer 21. Within the above range, the storage modulus is easily controlled. This ensures a storage modulus that presses the black curable resin layer 20 during thermocompression bonding. Furthermore, within the above range, flow during thermal curing can be suppressed, and poor appearance after curing, such as a repellency phenomenon, can be suppressed. Furthermore, problems are unlikely to occur when etching is performed in a subsequent process. Furthermore, when the amount is equal to or greater than the above lower limit, heat resistance is improved in the cured state.

[0073] (Elastomer) The transparent curable resin layer 21 preferably contains an elastomer in addition to a resin such as an epoxy resin. By containing an elastomer, it becomes easy to control the storage modulus. As the elastomer, the same types as those of the black curable resin layer 20 can be mentioned. Among them, NBR is preferable for the following reasons. NBR has good compatibility with epoxy resin. In addition, it is because it can increase the storage modulus of the transparent curable resin layer 21 at around 150°C, and as a result, the adhesion between the transparent curable resin layer 21 and the black curable resin layer 20 becomes good. The preferable weight average molecular weight of the elastomer is the same as that of the black curable resin layer 20.

[0074] In particular, when the transparent curable resin layer 21 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 also acts as a curing agent for the epoxy resin. In addition, since it can react and bond with the epoxy resin, it improves heat resistance and reliability against thermal shock. Furthermore, the difference in polarity between the functional group and the resin skeleton has a favorable effect on dispersibility. This allows good dispersibility to be obtained when carbon black is contained in the transparent curable resin layer 21.

[0075] Examples of functional groups capable of reacting with an epoxy group include the same types as those of the black curable resin layer 20. Among them, an acid group or an acid anhydride group is preferred, and a carboxy group or a carboxylic acid anhydride group is particularly preferred, since they can be cured at low temperatures and can ensure a long pot life.

[0076] When the transparent curable resin layer 21 is composed of an epoxy resin composition, it particularly preferably contains modified NBR having a carboxy group. Examples of modified NBR having a carboxy group include the same types as those of the black curable resin layer 20. Two or more types of modified elastomers having a functional group capable of reacting with an epoxy group may be used in combination.

[0077] The blending amount of the elastomer in the transparent curable resin layer 21 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 21. Within the above range, the storage modulus can be controlled. Furthermore, when the blending amount is equal to or less than the upper limit, the storage modulus can be secured to press the black curable resin layer 20 during thermocompression bonding. Furthermore, flow during thermal curing can be suppressed, and poor appearance after curing such as a repellent phenomenon can be suppressed. Furthermore, problems are unlikely to occur when etching is performed in a later process. Furthermore, when the blending amount is equal to or more than the lower limit, the dispersibility of carbon black is improved. Furthermore, the film-forming property is improved, and the distribution of film thickness can be narrowed when the epoxy resin composition is applied to form a film.

[0078] (hardening agent) When the transparent curable resin layer 21 is made of an epoxy resin composition, it may contain a curing agent for other epoxy resins in addition to 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 20. Two or more types of the other curing agents may be used in combination.

[0079] (curing catalyst) When the transparent curable resin layer 21 is made of an epoxy resin composition, it may contain 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 20, and the preferred embodiments are also the same.

[0080] The blending 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 21. Within the above range, curing can be sufficiently promoted and the pot life of the integrated encapsulating sheet 2 can be secured. Two or more types of curing catalysts may be used in combination.

[0081] (Other Ingredients) The transparent curable resin layer 21 may contain a black pigment or black dye in order to suppress uneven light emission or color unevenness.

[0082] When the transparent curable resin layer 21 contains carbon black, the blending 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 parts by mass or less, relative to 100 parts by mass of the total resin solid content, from the viewpoint of increasing the total light transmittance. The transparent curable resin layer 21 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.

[0083] (3) Protective layer The protective layer 25 may be made of various known materials as long as it can protect the MIP element 1, but is preferably a glass layer or a resin layer from the viewpoints of impact resistance, heat resistance, weather resistance, etc. The glass layer and the resin layer will be described below.

[0084] (glass layer) The glass layer is a layer for protecting the MIP element 1 from scratches, etc. In this specification, "glass" refers to inorganic glass. The glass used for the glass layer is preferably in the form of a thin film.

[0085] The inorganic glass used in the glass layer is not particularly limited as long as it does not prevent the transmission of light from the light-emitting element, and may be any of various known materials such as soda-lime glass, borosilicate glass, quartz glass, etc. In addition, according to classification based on the alkali component, it is preferable to use alkali-free glass, low-alkali glass, etc.

[0086] The glass layer may be formed from a raw material, or may be a commercially available glass used as is or after polishing to a desired thickness. An example of commercially available glass is "G-Leaf (registered trademark)" manufactured by Nippon Electric Glass Co., Ltd.

[0087] When forming the glass layer, any suitable method may be used. For example, the glass layer is produced by melting a mixture containing a main raw material such as silica, an antifoaming agent such as mirabilite or antimony oxide, and a reducing agent such as carbon at a temperature of 1400°C to 1600°C, forming it into a thin plate, and then cooling it. The forming method of the glass layer is, for example, a slot downdraw method, a fusion method, a float method, etc. Inorganic glass formed into a film by these methods may be chemically polished with a solvent such as hydrofluoric acid as necessary to make it thin or to increase the smoothness.

[0088] [Total light transmittance] The total light transmittance of the glass layer is not particularly limited as long as it does not prevent the transmission of light from the light emitting element, but is preferably 50% to 99%, more preferably 60% to 99%. By setting the total light transmittance of the glass layer to the lower limit or more, the light is not prevented from reaching the viewer side.

[0089] [Storage modulus] The storage modulus of the glass layer is not particularly limited, but is preferably 1.0×10 9 Pa or more 5.0×10 11 Pa or less, more preferably 2.0×10 9 Pa or more 3.0×10 11 Pa or less, and even more preferably 3.0×10 9 Pa or more 1.0×1011 Pa or less. By setting the storage modulus to a preferred upper limit or less, it is possible to impart appropriate flexibility that does not hinder the flow of the black curable resin layer 20 when it is pressed onto the multiple micro LEDs 11, 12, and 13. This allows the black curable resin layer 20 to sufficiently fill the spaces between the micro LEDs 11, 12, and 13. By setting the storage modulus to a preferred lower limit or more, the glass layer can reliably transmit pressure to the black curable resin layer 20 and the transparent curable resin layer 21 without being deformed when it is pressed onto the multiple micro LEDs 11, 12, and 13.

[0090] [Film thickness] The thickness of the glass layer is not particularly limited as long as it does not prevent the transmission of light from the light emitting element, but is preferably 30 to 70 μm, more preferably 40 to 60 μm, and even more preferably 45 to 55 μm. By setting the thickness to a preferable lower limit or more, sufficient strength for protecting the micro LEDs 11, 12, and 13 can be ensured. By setting the thickness to a preferable upper limit or less, the visibility of the light from the micro LEDs 11, 12, and 13 can be improved while the manufacturing cost can be reduced.

[0091] [hardness] The pencil hardness of the glass layer surface is preferably 7H or more, more preferably 8H or more, and even more preferably 9H or more. By setting the pencil hardness to be equal to or more than the lower limit, the integral encapsulating sheet 2 can be provided with sufficient durability as the protective layer 25. In addition, by using the glass layer, it is not necessary to form a hard coat layer for scratch prevention on the outer surface.

[0092] [Reflectance] The reflectance measured by a glossmeter (JIS Z 8741) on the glass layer side is preferably 1 to 50%, more preferably 3 to 30%, and even more preferably 5 to 25%. By setting the reflectance to be equal to or higher than the lower limit, production can be facilitated. Furthermore, by setting the reflectance to be equal to or lower than the upper limit, visibility of the display can be improved.

[0093] [Total light transmittance across both layers] The total light transmittance of the two layers, the transparent curable resin layer 21 and the glass layer, is preferably 30 to 95%, more preferably 35 to 95%, and even more preferably 40 to 95%. By setting the total light transmittance of the two layers to the lower limit or more, the light reaching the viewer side can be prevented as much as possible.

[0094] The glass layer may be colored to prevent uneven light emission and color.

[0095] (Resin layer) FIG. 2 shows a cross-sectional view of another integrated encapsulating sheet used in a manufacturing method according to an embodiment, taken along the same line as FIG. 1. The integrated encapsulating sheet may have a resin layer instead of a glass layer as a protective layer. The protective layer 25b, which is a resin layer, is preferably a layer obtained by laminating at least a hard coat layer 27 that protects the MIP element 1 and a support film layer 26 that supports the hard coat layer 27. That is, as shown in FIG. 2, the integrated encapsulating sheet 2b having the protective layer 25b is a laminate obtained by laminating a black curable resin layer 20, a transparent curable resin layer 21, a support film layer 26, and a hard coat layer 27 in this order. In the manufacturing method according to the present embodiment, the integrated encapsulating sheet 2b can be used in place of the integrated encapsulating sheet 2.

[0096] The hard coat layer 27 and / or the support film layer 26 may be colored to prevent uneven light emission and color unevenness.

[0097] (Support Film Layer) The support film layer 26 is a layer for protecting the micro LEDs 11, 12, and 13 from external physical impact, humidity, moisture, etc. The support film layer 26 also serves as the support film layer 26 for forming layers such as the black curable resin layer 20, the transparent curable resin layer 21, and the hard coat layer 27.

[0098] [Total Light Transmittance] The total light transmittance of the support film layer 26 is adjusted to be preferably 30 to 99%, more preferably 35 to 95%, and even more preferably 40 to 95%. When the total light transmittance of the support film layer 26 is equal to or greater than the lower limit, the light is not prevented from reaching the viewer's side.

[0099] [Storage modulus] The storage modulus of the support film layer 26 at 60° C. is preferably 7×10 8 Pa or more 2×10 10 Pa or less, and more preferably 1×10 9 Pa or more 1×10 10 Pa or less, and even more preferably 2×10 9 Pa or more 6×10 9 When the storage modulus at 60° C. of the support film layer 26 is equal to or less than the preferred upper limit, cracking of the support film layer 26 can be reduced.

[0100] [Resin] The support film layer 26 may be made of a thermoplastic resin or a thermosetting resin. Examples of the resin constituting the support film layer 26 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, and polyimide resin. In terms of heat resistance, weather resistance, availability, cost, and the like, it is preferable to include at least one resin selected from polyethylene terephthalate resin, polyethylene 2,6-naphthalate resin, polycarbonate resin, polycarbonate copolymer resin, and polyamide resin. By including these resins, deformation during pressure bonding can be prevented. The support film layer 26 may contain a black pigment or black dye to suppress uneven light emission and color unevenness.

[0101] [Film Thickness] The thickness of the support film layer 26 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 layer 26 is equal to or more than the preferable lower limit, it is possible to suppress the occurrence of wrinkles when the integrated encapsulating sheet 2 is thermocompression-bonded to the plurality of micro LEDs 11, 12, and 13, and also to improve the handling properties. When the thickness of the support film layer 26 is equal to or less than the preferable upper limit, it is possible to improve the visibility and reduce the cost.

[0102] (Hard Coat Layer) [Hardness] The hard coat layer 27 is a layer for protecting the light-emitting electronic component from scratches. The pencil hardness of the surface of the hard coat layer 27 is preferably H or more, more preferably 2H or more, and even more preferably 3H or more.

[0103] [Surface Roughness] The arithmetic surface roughness (Ra) of the surface of the hard coat layer 27 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 27 is equal to or greater than the preferred lower limit, the reflectance of the surface of the hard coat layer 27 can be reduced. When the Ra of the hard coat layer 27 is equal to or less than the preferred upper limit, production can be facilitated.

[0104] [Total Light Transmittance] The hard coat layer 27 is preferably prepared so that the total light transmittance is 30 to 99%, more preferably 50 to 99%, and further preferably 60 to 99%. When the total light transmittance of the hard coat layer 27 is equal to or higher than the lower limit, the light reaching the viewer side is not hindered.

[0105] [resin] The hard coat layer 27 may be made of either a thermoplastic resin or a thermosetting resin, and is preferably made of a thermosetting resin. Examples of the thermosetting resin constituting the hard coat layer 27 include an acrylic resin, a urethane resin, a silicone resin, a melamine resin, and the like, and the hard coat layer 27 may contain one or more of these. The hard coat layer 27 may contain a black pigment or dye.

[0106] [Fine Particles] The hard coat layer 27 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 them, silica fine particles are preferable. By containing fine particles, it is possible to adjust the surface roughness of the hard coat layer 27 and improve the surface hardness.

[0107] [Film Thickness] The thickness of the hard coat layer 27 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 27 is equal to or greater than the preferred lower limit, sufficient hardness can be ensured. When the thickness of the hard coat layer 27 is equal to or less than the preferred upper limit, defects such as curling are not caused.

[0108] (4) Protective sheet The protective sheets 22 and 23 have a role of protecting the integrated encapsulating sheets 2 and 2b. The protective sheet 22 can also be used as a sheet for applying a coating liquid of a curable resin composition when the integrated encapsulating sheets 2 and 2b are formed.

[0109] The protective sheets 22, 23 may be, for example, sheets made of polyesters such as polyethylene terephthalate and polyethylene naphthalate, thermoplastic resins such as polyimide, polyamide-imide, polyethylene, polytetrafluoroethylene, polypropylene, and polystyrene, or surface-treated paper.

[0110] Among these, polyester sheets are preferably used from the viewpoints of heat resistance, mechanical strength, ease of handling, etc. The thickness of the protective sheets 22, 23 is not particularly limited and is appropriately selected from the range of about 10 to 150 μm depending on the application. The surface of the protective sheet 22 on which the resin layer is to be provided may be subjected to a release treatment.

[0111] 2. Manufacturing method of integrated encapsulating sheet In order to obtain the integrated encapsulating sheet 2 having the protective layer 25 as a glass layer, first, a protective sheet 22 is prepared by applying and drying a coating liquid of a curable resin composition for the black curable resin layer 20, and a glass layer is prepared by applying and drying a coating liquid of a curable resin composition for the transparent curable resin layer 21.

[0112] Thereafter, these are stacked and laminated so that the transparent curable resin layer 21 and the black curable resin layer 20 are in contact with each other, thereby obtaining a laminate in which the black curable resin layer 20, the transparent curable resin layer 21, and the glass layer (i.e., the protective layer 25) are sequentially stacked on the protective sheet 22. A protective sheet 23 may be laminated on the outer surface of the glass layer as necessary.

[0113] When a resin layer is used as the protective layer 25b, it is preferable to prepare a layer in which a coating liquid of a curable resin composition for the transparent curable resin layer 21 is applied and dried on the surface of the support film layer 26 on which the hard coat layer 27 has been formed in advance, the surface being opposite the hard coat layer 27.

[0114] Thereafter, by laminating in the same manner as described above, a laminate is obtained in which the black curable resin layer 20, the transparent curable resin layer 21, the support film layer 26, and the hard coat layer 27 are laminated in this order on the protective sheet 22. A protective sheet 23 may be laminated on the outer surface of the hard coat layer 27 as necessary.

[0115] The coating liquid of the curable resin composition of the black curable resin layer 20 and / or the coating liquid of the curable resin composition of the transparent curable resin layer 21 preferably contains an organic solvent in an amount that provides a viscosity that allows coating to be performed without problems. The organic solvent is not particularly limited, and 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 in the coating liquid, carbon black powder may be added to the coating liquid, or a liquid in which carbon black has been previously dispersed (carbon black dispersion) may be added.

[0116] Examples of the method for applying the curable resin composition include methods using 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.

[0117] 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 to a preferred lower limit or higher, it is possible to ensure adhesion between the black curable resin layer 20 and the transparent curable resin layer 21 that allows handling even in uncured state. Furthermore, by setting the temperature to a preferred upper limit or lower, it is possible to prevent air bubbles from being trapped between the black curable resin layer 20 and the transparent curable resin layer 21 and the occurrence of wrinkles in each layer 20, 21. Lamination can be performed using, for example, a roll laminator, a press machine, a vacuum press machine, or the like.

[0118] 3. Manufacturing method of MIP element and MIP element (First embodiment) 3 is a flow diagram of a manufacturing method according to one embodiment. The manufacturing method of the MIP device 1 according to the present invention is a manufacturing method of the MIP device 1 integrating a plurality of micro LEDs 11, 12, and 13, and includes the steps described in (1) to (11) below. (1) A process of fixing the light emitting surfaces 14 of the micro LEDs 11, 12, and 13 on the first substrate 50 (hereinafter, referred to as a first fixing process). (2) A process of fixing the electrodes 15 located on the surface opposite to the light-emitting surface 14 of the multiple micro LEDs 11, 12, and 13 to the first electrode adhesive layer 61 on the second substrate 60 (hereinafter, referred to as the second fixing process). (3) A step of separating the first substrate 50 from the light-emitting surface 14 (hereinafter, referred to as a first separation step). (4) A process of fixing the light-emitting surfaces 14 of the multiple micro LEDs 11, 12, and 13 to the light-emitting surface adhesive layer 71 on the third substrate 70 (hereinafter, referred to as the third fixing process). (5) A step of separating the second substrate 60 from the electrode 15 (hereinafter, referred to as a second separation step). (6) A process of fixing electrodes of the multiple micro LEDs 11, 12, and 13 to the second electrode adhesive layer 81 on the fourth substrate 80 (hereinafter, referred to as a fourth fixing process). (7) A step of separating the third substrate 70 from the light-emitting surface 14 (hereinafter, referred to as a third separation step). (8) A process of pressing the integrated encapsulating sheet 2, in which the black curable resin layer 20, the transparent curable resin layer 21, and the protective layer 25 are laminated in this order, to the multiple micro LEDs 11, 12, and 13 so that the surface on the black curable resin layer 20 side is in contact with the light emitting surface 14 side (hereinafter referred to as a pressing process). (9) A process of filling at least the black curable resin layer 20 between the multiple micro LEDs 11, 12, and 13 (hereinafter, referred to as a filling process) of the black curable resin layer 20 and the transparent curable resin layer 21. (10) A step of curing the black curable resin layer 20 and the transparent curable resin layer 21 (hereinafter referred to as a curing step). (11) A process of separating the fourth substrate 80 from the electrode 15 and exposing the electrode 15 to the outside of the black resin layer 30 obtained by curing the black curable resin layer 20 (hereinafter, referred to as a fourth separation process).

[0119] Each of steps (1) to (11) will be described below.

[0120] (1) First fixing process (S110) 4 is a cross-sectional view showing a schematic state after a first fixing step in a manufacturing method according to an embodiment. The first fixing step is a step of fixing the light emitting surfaces 14 of the micro LEDs 11, 12, and 13 on the first substrate 50. In this embodiment, the micro LEDs 11, 12, and 13 each have a light emitting surface 14 and an electrode 15 on the surface opposite to the light emitting surface 14. After this step, the micro LEDs 11, 12, and 13 each have a light emitting surface 14 fixed to the first substrate 50 and an electrode 15 exposed.

[0121] The first substrate 50 is a substrate for supporting the multiple micro LEDs 11, 12, and 13 in a second fixing step described later. The first substrate 50 can be any known substrate capable of fixing the multiple micro LEDs 11, 12, and 13, but is preferably a substrate transparent to laser light, and more preferably a sapphire substrate, a GaAs substrate, or the like.

[0122] The method of fixing the micro LEDs 11, 12, and 13 to the first substrate 50 is not particularly limited, and any known method can be used. The micro LEDs 11, 12, and 13 fixed to the first substrate 50 may be formed on the first substrate 50 from a crystal layer such as gallium nitride (GaN), or may be formed on another substrate. Among them, a method of epitaxially growing a crystal layer such as GaN on the first substrate 50, processing it into a desired size and shape, and forming an electrode or the like on the upper portion is preferable. In addition, the micro LEDs 11, 12, and 13 are preferably fixed at equal intervals.

[0123] (2) Second fixing process (S120) 5 is a cross-sectional view showing a schematic state after a second fixing step in a manufacturing method according to an embodiment. The second fixing step is a step of fixing the electrodes 15 located on the surfaces of the micro LEDs 11, 12, and 13 opposite to the light emitting surfaces 14 to the first electrode adhesive layer 61 on the second substrate 60. After this step, the light emitting surfaces 14 of the micro LEDs 11, 12, and 13 are fixed to the first substrate 50 and the electrodes 15 are fixed to the first electrode adhesive layer 61 on the second substrate 60.

[0124] The second substrate 60 is a substrate for fixing the micro LEDs 11, 12, and 13 so that they do not separate from each other when the first substrate 50 is removed in a first separation step described later. The second substrate 60 includes a first electrode adhesive layer 61 having a predetermined adhesive strength for fixing the electrode 15. The second substrate 60 can be any known substrate such as a quartz substrate as long as it is capable of fixing the multiple micro LEDs 11, 12, and 13.

[0125] The first electrode adhesive layer 61 is an adhesive layer provided on the second substrate 60, and has cushioning properties that can absorb the impact when the first substrate 50 is separated from the light-emitting surface 14. The first electrode adhesive layer 61 may be made of any known material that can fix the electrode 15, such as polyimide, benzocyclobutene, or silicone resin. Among these, it is preferable to use silicone resin.

[0126] The thickness of the first electrode adhesive layer 61 is not particularly limited as long as it can absorb the impact when the first substrate 50 is separated from the light-emitting surface 14, but is preferably 5 to 10 times, more preferably 6 to 9 times, and even more preferably 7 to 8 times the height of the micro LEDs 11, 12, and 13.

[0127] (3) First separation step (S130) 6 is a cross-sectional view showing a schematic state after a first separation step in a manufacturing method according to an embodiment. The first separation step is a step of separating the first substrate 50 from the light-emitting surface 14. After this step, the electrodes 15 of the micro LEDs 11, 12, and 13 are fixed to the first electrode adhesive layer 61 on the second substrate 60, and the light-emitting surface 14 is exposed.

[0128] The method for separating the first substrate 50 from the light emitting surface 14 side can be any known method, but the laser lift-off technique is preferable.

[0129] (4) Third fixing process (S140)

[0130] 7 is a cross-sectional view showing a schematic state after a third fixing step in a manufacturing method according to an embodiment. The third fixing step is a step of fixing the light-emitting surfaces 14 of the micro LEDs 11, 12, and 13 to the light-emitting surface adhesive layer 71 on the third substrate 70. After this step, the light-emitting surfaces 14 of the micro LEDs 11, 12, and 13 are fixed to the light-emitting surface adhesive layer 71 on the third substrate 70 and the electrodes 15 are fixed to the first electrode adhesive layer 61 on the second substrate 60.

[0131] The third substrate 70 is a substrate for fixing the micro LEDs 11, 12, and 13 so that they do not separate from each other when the second substrate 60 is removed in a second separation step described later. The third substrate 70 includes a light-emitting surface adhesive layer 71 having a predetermined adhesive strength for fixing the light-emitting surface 14. The third substrate 70 can be any known substrate, such as a quartz substrate, as long as it is capable of fixing the multiple micro LEDs 11, 12, and 13.

[0132] The light-emitting surface adhesive layer 71 is an adhesive layer provided on the third substrate 70, and serves to fix the micro LEDs 11, 12, and 13 when the second substrate 60 is separated from the electrode 15. The material forming the light-emitting surface adhesive layer 71 may be the same as or different from the material forming the first electrode adhesive layer 61. In addition, the thickness of the light-emitting surface adhesive layer 71 is not particularly limited as long as it is capable of fixing the light-emitting surfaces 14 of the micro LEDs 11, 12, and 13.

[0133] (5) Second separation step (S150) 8 is a cross-sectional view showing a schematic state after a second separation step in the manufacturing method according to one embodiment. The second separation step is a step of separating the second substrate 60 from the electrode 15. After this step, the light-emitting surfaces 14 of the micro LEDs 11, 12, and 13 are fixed to the light-emitting surface adhesive layer 71 on the third substrate 70, and the electrode 15 is exposed.

[0134] The method for separating the second substrate 60 is not particularly limited, and various known methods may be used, preferably UV irradiation or heating.

[0135] (6) Fourth fixing process (S160) 9 is a cross-sectional view showing a schematic state after a fourth fixing step in the manufacturing method according to one embodiment. The fourth fixing step is a step of fixing the electrode 15 side of the micro LEDs 11, 12, and 13 to the second electrode adhesive layer 81 on the fourth substrate 80. After this step, the light emitting surface 14 side of the micro LEDs 11, 12, and 13 is fixed to the light emitting surface adhesive layer 71 on the third substrate 70, and the electrode 15 side is fixed to the second electrode adhesive layer 81 on the fourth substrate 80.

[0136] The fourth substrate 80 is a substrate for fixing the micro LEDs 11, 12, and 13 so that they do not separate from each other when the third substrate 70 is removed in a third separation step described later. The fourth substrate 80 also serves as a substrate for supporting the micro LEDs 11, 12, and 13 when the integrated encapsulating sheet 2 is press-bonded to the light emitting surface 14 side in a compression bonding step described later. The fourth substrate 80 includes a second electrode adhesive layer 81 having a predetermined adhesive force for fixing the electrode 15. The fourth substrate 80 can be any known substrate such as a quartz substrate as long as it can fix the micro LEDs 11, 12, and 13.

[0137] The second electrode adhesive layer 81 is an adhesive layer provided on the fourth substrate 80, and serves to fix the micro LEDs 11, 12, and 13 when the third substrate 70 is separated from the light emitting surface 14. The hardness of the second electrode adhesive layer 81 is higher than the hardness of the first electrode adhesive layer 61. This makes it difficult for the micro LEDs 11, 12, and 13 to be embedded in the adhesive layer in the compression bonding process described below. Here, the "hardness" is measured by a nanoindentation method.

[0138] The material forming the second electrode adhesive layer 81 may be the same as or different from the first electrode adhesive layer 61 described above. Among them, it is preferable to use a silicone resin. Also, the second electrode adhesive layer 81 is preferably formed thinner than the first electrode adhesive layer 61 in the drawings, but the embodiment of the present invention is not limited thereto. That is, the second electrode adhesive layer 81 may be formed to the same thickness as the first electrode adhesive layer 61 or thicker than the first electrode adhesive layer 61, so long as it has a higher hardness than the first electrode adhesive layer 61.

[0139] (7) Third separation step (S170) 10 is a cross-sectional view showing a schematic state after a third separation step in a manufacturing method according to an embodiment. The third separation step is a step of separating the third substrate 70 from the light-emitting surface 14. After this step, the electrodes 15 of the micro LEDs 11, 12, and 13 are fixed to the second electrode adhesive layer 81 on the fourth substrate 80, and the light-emitting surface 14 is exposed.

[0140] The method for separating the third substrate 70 is not particularly limited, and any known method similar to or different from the second separation step described above can be used.

[0141] (8) Crimping process (S180) 11 is a cross-sectional view showing a schematic state after a pressure bonding step in a manufacturing method according to an embodiment. The pressure bonding step is a step of pressure bonding an integrated encapsulating sheet 2 having a black curable resin layer 20, a transparent curable resin layer 21, and a protective layer 25 laminated in this order such that the surface of the black curable resin layer 20 is in contact with the light emitting surface 14. The pressure bonding is preferably thermal pressure bonding.

[0142] In one embodiment of the manufacturing method, first, as shown in FIG. 11, an integrated encapsulating sheet 2, from which the protective sheet 22 has been peeled off to expose the black curable resin layer 20, is placed on the surface of the fourth substrate 80 on which the micro LEDs 11, 12, and 13 are arranged, so that the black curable resin layer 20 is in contact with the surface.

[0143] Before thermocompression bonding, the thickness of the black curable resin layer 20 is preferably 10 to 95% of the height of the micro LEDs 11, 12, and 13. 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.

[0144] When the thickness of the black curable resin layer 20 is 10% or more of the height of the micro LEDs 11, 12, 13, the light-shielding function between the micro LEDs 11, 12, 13 is sufficient. In addition, when the storage modulus of the black curable resin layer 20 is relatively low and the layer 20 is highly fluid, the resin can be sufficiently filled between the micro LEDs 11, 12, 13. When the thickness of the black curable resin layer 20 is 15% or more of the height of the micro LEDs 11, 12, 13, even if the fluidity of the transparent curable resin layer 21 is relatively low, crack-like defects are unlikely to occur on the surface. When the thickness of the black curable resin layer 20 is 30% or more of the height of the micro LEDs 11, 12, 13, the black curable resin layer 20 having the light-shielding function can be appropriately filled between the micro LEDs 11, 12, 13.

[0145] If the thickness of the black curable resin layer 20 is 95% or less of the height of the micro LEDs 11, 12, and 13, leakage of the black curable resin layer 20 to the outside during thermocompression bonding can be prevented, and light from the micro LEDs 11, 12, and 13 is unlikely to be hindered from reaching the viewer. If the thickness of the black curable resin layer 20 is 85% or less of the height of the micro LEDs 11, 12, and 13, the film thickness of the black curable resin layer 20 that flows after pressing is unlikely to vary, and black shading is unlikely to occur. If the thickness of the black curable resin layer 20 is 75% or less of the height of the micro LEDs 11, 12, and 13, the black curable resin layer 20 having a light-shielding function can be appropriately filled between the micro LEDs 11, 12, and 13.

[0146] The thickness of the transparent curable resin layer 21 before compression bonding is preferably 10 to 500% of the height of the micro LEDs 11, 12, and 13. 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.

[0147] When the thickness of the transparent curable resin layer 21 is 10% or more relative to the height of the micro LEDs 11, 12, and 13, it is easy to function as a sealing layer covering the micro LEDs 11, 12, and 13. In addition, when the storage modulus of the transparent curable resin layer 21 is relatively high and the fluidity of the transparent curable resin layer 21 is suppressed, the transparent curable resin layer 21 can be suppressed from flowing together with the black curable resin layer 20 during thermal curing, and appearance defects are unlikely to occur on the surface. When the thickness of the transparent curable resin layer 21 is 20% or more relative to the height of the micro LEDs 11, 12, and 13, the range in which the transparent curable resin layer 21 can be allowed to flow is sufficient, and crack-like defects are unlikely to occur on the surface. When the thickness of the transparent curable resin layer 21 is 30% or more relative to the height of the micro LEDs 11, 12, and 13, the transparent curable resin layer 21 is easy to function as a sealing layer covering the micro LEDs 11, 12, and 13. Furthermore, when the storage modulus of the transparent curable resin layer 21 is relatively high and the fluidity of the transparent curable resin layer 21 is suppressed, the transparent curable resin layer 21 can sufficiently press into the black curable resin layer 20.

[0148] The total thickness of the black curable resin layer 20 and the transparent curable resin layer 21 before compression bonding is preferably 110 to 550% with respect to the height of the micro LEDs 11, 12, and 13. If the total thickness is equal to or more than the above-mentioned lower limit with respect to the height of the micro LEDs 11, 12, and 13, a part of the integrated encapsulating sheet 2 can be sufficiently embedded between the micro LEDs 11, 12, and 13. If the total thickness is equal to or less than the above-mentioned upper limit with respect to the height of the micro LEDs 11, 12, and 13, thickness unevenness is unlikely to occur during compression bonding, and appearance defects are unlikely to occur on the surface.

[0149] The ratio of the thickness of the black curable resin layer 20 before compression to the total thickness of the transparent curable resin layer 21 and the black curable resin layer 20 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 curable resin layer 20 is unlikely to remain on the micro LEDs 11, 12, and 13 during compression, and the brightness can be sufficiently improved.

[0150] (9) Filling process (S190) 12 is a cross-sectional view showing a schematic state after a filling step in a manufacturing method according to an embodiment. The filling step is a step of filling at least the black curable resin layer 20, which is the black curable resin layer 20 and the transparent curable resin layer 21, between the micro LEDs 11, 12, and 13. After this step, the integrated encapsulating sheet 2 is in a state where the black curable resin layer 20 side is pressed directly onto the second electrode adhesive layer 81.

[0151] 11, the black curable resin layer 20 and a part of the transparent curable resin layer 21 of the integrated encapsulating sheet 2 are embedded between the micro LEDs 11, 12, and 13 as shown in FIG. 12. At this time, if the storage modulus of the black curable resin layer 20 is relatively low and the fluidity of the layer 20 is ensured, the black curable resin layer 20 is likely to be filled between the micro LEDs 11, 12, and 13 by following the unevenness of the micro LEDs 11, 12, and 13, and is unlikely to remain on the micro LEDs 11, 12, and 13. As a result, the manufacturing method of the MIP element 1 according to this embodiment does not require a process of etching the black layer remaining on the light emitting surfaces 14 of the micro LEDs 11, 12, and 13, which contributes to shortening the process time.

[0152] The temperature in the thermocompression bonding is preferably 80 to 120°C, and more preferably 90 to 110°C. By setting the temperature at 80°C or higher, the fluidity of the black curable resin layer 20 and the transparent curable resin layer 21 is easily ensured. Furthermore, by setting the temperature at 120°C or lower, the micro LEDs 11, 12, and 13 are less likely to be damaged. By setting the temperature at 90 to 110°C, the fluidity of the black curable resin layer 20 and the transparent curable resin layer 21 can be more precisely controlled, and the occurrence of unevenness or crack-like defects can be suppressed.

[0153] The pressure in the thermocompression bonding is preferably 0.05 to 1.0 MPa, more preferably 0.1 to 0.5 MPa. By setting the pressure to a preferable lower limit or more, the black curable resin layer 20 does not remain on the micro LEDs 11, 12, and 13, and the light from the micro LEDs 11, 12, and 13 is not prevented from reaching the viewer. By setting the pressure to a preferable upper limit or less, the micro LEDs 11, 12, and 13 are less likely to be damaged. The thermocompression bonding is preferably performed using a vacuum press machine capable of molding in a vacuum state. This makes it easy to avoid defects caused by air being mixed into the obtained MIP element 1.

[0154] (10) Curing process (S200) FIG. 13 is a cross-sectional view showing a schematic state after a curing process in a manufacturing method according to an embodiment. The curing process is a process of curing the black curable resin layer 20 and the transparent curable resin layer 21 filled between the micro LEDs 11, 12, and 13. The curing is not particularly limited, but is preferably thermal curing. After this process, the micro LEDs 11, 12, and 13 are in a state in which the electrodes 15 are fixed to the second electrode adhesive layer 81 on the fourth substrate 80. In addition, the micro LEDs 11, 12, and 13 are in a state in which the light emitting surface 14 side to the electrodes 15 are sealed by the integrated sealing cured sheet 3 after the curing process of the integrated sealing sheet 2.

[0155] After the pressing and filling steps, as shown in FIG. 13, the protective sheet 23 is peeled off and then thermally cured, so that the black curable resin layer 20 of the integrated encapsulating sheet 2 becomes the black resin layer 30 (cured layer of the black curable resin layer 20), and the transparent curable resin layer 21 becomes the transparent resin layer 31 (cured layer of the transparent curable resin layer 21).

[0156] 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 black curable resin layer 20 and the transparent curable resin layer 21 can be reliably cured. By setting the curing temperature to 110° C. or higher, the curing time of the black curable resin layer 20 and the transparent curable resin layer 21 can be shortened. In addition, by setting the curing temperature to the above upper limit temperature or lower, the micro LEDs 11, 12, and 13 are less likely to be damaged.

[0157] 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 21 is relatively high and the fluidity of the layer 21 is suppressed at the curing temperature, poor appearance of the black curable resin layer 20 and the transparent curable resin layer 21 after curing can be suppressed.

[0158] (11) Fourth separation step (S210) 14 is a cross-sectional view showing a schematic state after a fourth separation step in the manufacturing method according to an embodiment. The fourth separation step is a step of separating the second electrode adhesive layer 81 on the fourth substrate 80 from the multiple micro LEDs 11, 12, and 13.

[0159] The method for separating the fourth substrate 80 is not particularly limited as long as it does not affect the sealing of the micro LEDs 11, 12, and 13 by the integrated sealing cured sheet 3, but is preferably UV irradiation or heating.

[0160] 4 to 14, the MIP element 1 is obtained in which the integrated encapsulation cured sheet 3 is pressure-bonded to the micro LEDs 11, 12, and 13. In the obtained MIP element 1, the black curable resin layer 20 and the transparent curable resin layer 21 are cured. Parts of the black resin layer 30 and the transparent resin layer 31 are filled between the multiple micro LEDs 11, 12, and 13. In addition, at least parts of the electrodes 15 of the multiple micro LEDs 11, 12, and 13 are exposed from the integrated encapsulation cured sheet 3.

[0161] The MIP element 1 is a light-emitting element in which multiple micro LEDs 11, 12, and 13 are integrated. As shown in Fig. 14, the MIP element 1 manufactured by the manufacturing method according to the present invention has a structure in which multiple micro LEDs 11, 12, and 13 are encapsulated by an integrated encapsulating cured sheet 3. The multiple micro LEDs 11, 12, and 13 are encapsulated by the integrated encapsulating cured sheet 3 except for at least a part of each electrode 15. The integrated encapsulating cured sheet 3 is a sheet obtained by curing the integrated encapsulating sheet 2, and includes a black resin layer 30, a transparent resin layer 31, and a protective layer 25 laminated in this order from the electrode 15 side.

[0162] The thickness of the transparent resin layer 31 is not particularly limited, but is preferably 0.1 to 5.0 times the height of the multiple micro LEDs 11, 12, and 13. The thickness of the black resin layer 30 is not particularly limited, but is preferably 0.1 to 0.9 times the height of the multiple micro LEDs 11, 12, and 13.

[0163] The number of micro LEDs 11, 12, 13 provided in the MIP element 1 is not particularly limited as long as it is a plurality, but is preferably three. The MIP element 1 manufactured by the manufacturing method according to this embodiment includes three micro LEDs. Although three micro LEDs 11, 12, 13 are illustrated in FIG. 14 , the number of micro LEDs 11, 12, 13 provided in the MIP element 1 may be two or four or more. Furthermore, the light emission colors of the micro LEDs 11, 12, 13 are not particularly limited, but are preferably LEDs that emit red, green, and blue light.

[0164] Second embodiment Next, the second embodiment will be described. The same reference numerals are used for parts common to the first embodiment, and duplicated explanations will be omitted. FIG. 15 shows a flow diagram of a manufacturing method according to another embodiment. FIG. 16 shows a cross-sectional view that shows a schematic state before and after a moving step in a manufacturing method according to another embodiment. The second embodiment includes a moving step (2-2) instead of the second fixing step (2) and the first separation step (3) among the steps (1) to (11) of the manufacturing method according to the first embodiment described above. That is, the second embodiment is performed in the order of the first fixing step (1), the moving step (2-2), and the third fixing step (4). The steps after (5) are the same as those in the first embodiment.

[0165] (2-2) Moving process (S125) The moving step is a step of bringing the first electrode adhesive layer 61 on the second substrate 60 close to the electrode 15 side of the multiple micro LEDs 11, 12, 13 fixed on the first substrate 50, separating the light emitting surface 14 from the first substrate 50, and fixing the multiple micro LEDs 11, 12, 13 to the first electrode adhesive layer 61. After this step, the multiple micro LEDs 11, 12, 13 are in a state where the electrode 15 side is fixed to the first electrode adhesive layer 61 on the second substrate 60 and the light emitting surface 14 side is exposed.

[0166] The distance between the first substrate 50 and the second substrate 60 during the above process is not particularly limited as long as the electrodes 15 of the multiple micro LEDs 11, 12, 13 separated from the first substrate 50 by laser lift-off or the like can be securely fixed to the first electrode adhesive layer 61 on the second substrate 60.

[0167] Third embodiment Next, a third embodiment will be described. The same reference numerals are used for parts common to the first or second embodiment, and duplicated explanations will be omitted. The third embodiment further includes a conductive layer forming step (12) of forming a conductive layer 40 on the electrode 15 after each of the steps (1) to (11) of the manufacturing method according to the first or second embodiment described above.

[0168] (12) Conductive layer formation process (S220) Fig. 17 shows a flow diagram of a manufacturing method according to another embodiment. Fig. 18 shows a cross-sectional view that shows a schematic state after a conductive layer forming step in a manufacturing method according to another embodiment. The conductive layer forming step is a step of forming a conductive layer 40 that allows electricity to be applied to the micro LED from the outside for each electrode 15 after the second substrate 60 is separated. After this step, an MIP element 1a is obtained in which each electrode 15 exposed from the integral encapsulation cured sheet 3 is covered with each conductive layer 40.

[0169] The conductive layer 40 is not particularly limited as long as it is a material capable of conducting electricity, and may be made of various known materials, such as copper, brass, silver, tungsten, graphite, and alloys or mixtures thereof. The conductive layer 40 may be made of a conductive resin composition, preferably containing a curable resin, a conductive filler such as a metal-based filler and / or a carbon-based filler, and additives, solvents, and the like, as necessary. The curable resin used for the conductive layer 40 may be the same as that used for the integrated sealing sheet 2, or may be another known curable resin.

[0170] The method for forming the conductive layer 40 is not particularly limited, and any known method can be used, and preferably a screen printing method, a dispensing method, an inkjet method, etc. When the conductive layer 40 is formed from the above-mentioned conductive resin composition, it is preferably formed on the electrode 15 by a known method, and then cured by heating or UV irradiation. [Industrial Applicability]

[0171] The present invention can be used in the production of MIP elements for use in displays and the like. [Explanation of symbols]

[0172] DESCRIPTION OF THE REFERENCE NUMERALS 1,1a...MIP element, 2,2b...integrated encapsulating sheet, 3...integrated encapsulating cured sheet, 11,12,13...micro LED, 14...light emitting surface, 15...electrode, 20...black curable resin layer, 21...transparent curable resin layer, 22,23...protective sheet, 25,25b...protective layer, 26...support film layer, 27...hard coat layer, 30...black resin layer, 31...transparent resin layer, 40...conductive layer, 50...first substrate, 60...second substrate, 61...first electrode adhesive layer, 70...third substrate, 80...fourth substrate, 81...second electrode adhesive layer.

Claims

1. A method for manufacturing a MIP device integrating a plurality of micro LEDs, comprising the steps of: Fixing the light emitting surface side of the plurality of micro LEDs on a first substrate; Fixing electrodes located on a surface opposite to the light emitting surface of the plurality of micro LEDs to a first electrode adhesive layer on a second substrate, the first electrode adhesive layer having a cushioning property capable of absorbing an impact when the first substrate is separated from the light emitting surface; separating the first substrate from the light emitting surface; Fixing the light emitting surfaces of the plurality of micro LEDs to a light emitting surface adhesive layer on a third substrate; separating the second substrate from the electrode; Fixing the electrodes of the plurality of micro LEDs to a second electrode adhesive layer on a fourth substrate, the second electrode adhesive layer having a harder hardness than the first electrode adhesive layer; separating the third substrate from the light emitting surface; A step of pressing an integrated encapsulating sheet having a black curable resin layer, a transparent curable resin layer, and a protective layer laminated in this order onto the plurality of micro LEDs such that a surface of the black curable resin layer is in contact with the light emitting surface; Filling at least the black curable resin layer between the micro LEDs; and curing the black curable resin layer and the transparent curable resin layer; separating the fourth substrate from the electrodes and exposing the electrodes to the outside of the cured black curable resin layer.

2. A method for manufacturing a MIP device integrating a plurality of micro LEDs, comprising the steps of: Fixing the light emitting surface side of the plurality of micro LEDs on a first substrate; a step of bringing a first electrode adhesive layer, which is an adhesive layer on a second substrate and has a cushioning property capable of absorbing an impact when the first substrate is separated from the light emitting surface, close to an electrode located on a surface opposite to the light emitting surface of the plurality of micro LEDs, separating the light emitting surface from the first substrate and fixing the plurality of micro LEDs to the first electrode adhesive layer of the second substrate; Fixing the light emitting surfaces of the plurality of micro LEDs to a light emitting surface adhesive layer on a third substrate; separating the second substrate from the electrode; Fixing the electrodes of the plurality of micro LEDs to a second electrode adhesive layer on a fourth substrate, the second electrode adhesive layer having a harder hardness than the first electrode adhesive layer; separating the third substrate from the light emitting surface; A step of pressing an integrated encapsulating sheet having a black curable resin layer, a transparent curable resin layer, and a protective layer laminated in this order onto the plurality of micro LEDs such that a surface of the black curable resin layer is in contact with the light emitting surface; Filling at least the black curable resin layer between the micro LEDs; and curing the black curable resin layer and the transparent curable resin layer; separating the fourth substrate from the electrodes and exposing the electrodes to the outside of the cured black curable resin layer.

3. 3. The method for manufacturing a MIP element according to claim 1, further comprising the step of forming a conductive layer on the electrode after separation from the second electrode adhesive layer, which enables current to be applied to the micro LED from the outside.

4. 3. The method for manufacturing a MIP element according to claim 1, further comprising the step of: providing three micro-LEDs, each of which is an LED that emits red, green and blue light.

5. 3. The method for manufacturing a MIP element according to claim 1, wherein the height of the black resin layer is 0.1 to 0.9 times the height of the micro LEDs, and the height of the transparent resin layer obtained by curing the transparent curable resin layer is 0.1 to 5.0 times the height of the micro LEDs.

6. 3. The method for producing a MIP element according to claim 1, wherein the protective layer is a glass layer.

7. 7. The method for producing a MIP element according to claim 6, wherein the thickness of the glass layer is 30 to 70 μm.

8. 3. The method for producing a MIP element according to claim 1, wherein the protective layer is a resin layer.

9. 9. The method for producing a MIP element according to claim 8, wherein the resin layer is a layer formed by laminating at least a hard coat layer for protecting the MIP element and a support film layer for supporting the hard coat layer.

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