Method for manufacturing a display device

Abstract

The present invention provides a display device that can obtain excellent light transmittance and aesthetic appeal, and a method for manufacturing the display device. [Solution] The display device 10 comprises a plurality of light-emitting elements 20, a substrate 30 on which the light-emitting elements 20 are arranged in subpixel units constituting one pixel, and a cured resin film 40 connecting the plurality of light-emitting elements 20 and the substrate 30. The cured resin film 40 consists of a plurality of individual pieces, and has exposed portions 30a between the individual pieces where the substrate 30 is exposed. This makes it possible to obtain excellent light transmittance and aesthetics.

Description

[Technical Field]

[0001] This technology relates to a display device comprising an array of light-emitting elements, and a method for manufacturing such a display device. [Background technology]

[0002] Mini-LED and micro-LED (Light Emitting Diode) displays, which consist of tiny light-emitting elements arranged on a substrate, eliminate the need for a backlight required for liquid crystal displays, enabling thinner displays, wider color gamuts, higher resolution, and lower power consumption. Furthermore, because micro-LED displays have smaller light-emitting elements than conventional displays, they are also expected to be used in transparent display applications.

[0003] Patent Document 1 describes connecting a wafer on which LEDs are arranged in subpixel units to a corresponding substrate using an anisotropic conductive adhesive, and Patent Document 2 describes providing grooves between the LEDs to suppress connection failures due to the flow of the anisotropic conductive adhesive.

[0004] However, with conventional anisotropic conductive adhesives, adhesive resin and conductive particles remain between each LED pitch, preventing good light transmission and compromising the aesthetics of the display device and light-emitting device. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2017-157724 [Patent Document 2] Japanese Patent Publication No. 2017-216321 [Overview of the project] [Problems that the invention aims to solve]

[0006] The present technology has been proposed in view of such a conventional situation, and provides a display device capable of obtaining excellent light transmittance and aesthetics, and a method for manufacturing the display device.

Means for Solving the Problems

[0007] The display device according to the present technology includes a plurality of light-emitting elements, a substrate on which the light-emitting elements are arranged in sub-pixel units constituting one pixel, and a cured resin film connecting the plurality of light-emitting elements and the substrate. The cured resin film is composed of a plurality of pieces, and has an exposed portion where the substrate is exposed between the pieces.

[0008] The method for manufacturing a display device according to the present technology includes a piece forming step of forming a plurality of pieces made of a curable resin film on a base material, a pasting step of pasting the plurality of pieces on a substrate, and a mounting step of mounting light-emitting elements on the pieces pasted on the substrate in sub-pixel units constituting one pixel.

[0009] The light-emitting device according to the present technology includes a plurality of light-emitting elements, a substrate on which the light-emitting elements are arranged, and a cured resin film connecting the plurality of light-emitting elements and the substrate. The cured resin film is composed of a plurality of pieces, and has an exposed portion where the substrate is exposed between the pieces.

[0010] The method for manufacturing a light-emitting device according to the present technology includes a piece forming step of removing a part of a curable resin film formed on a base material and forming a plurality of pieces made of a curable resin film on the base material, a pasting step of pasting the plurality of pieces on a substrate, and a mounting step of mounting light-emitting elements on the pieces pasted on the substrate.

Advantages of the Invention

[0011] According to the present technology, by providing an exposed portion where the substrate is exposed between the pieces on which the light-emitting elements are mounted, excellent light transmittance and aesthetics can be obtained.

Brief Description of the Drawings

[0012] [Figure 1] FIG. 1 is a cross-sectional view schematically showing a configuration example of a display device. [Figure 2] FIG. 2 is a cross-sectional view schematically showing a configuration example when the size of each piece is smaller than the size of the light-emitting element. [Figure 3] FIG. 3 is a cross-sectional view schematically showing a configuration example when the size of each piece is larger than the size of the light-emitting element. [Figure 4] FIG. 4 is a cross-sectional view schematically showing a configuration example of a conventional display device. [Figure 5] FIG. 5(A) is a top view schematically showing a configuration example of a curable resin film formed on the entire surface of a base film, and FIG. 5(B) is a cross-sectional view schematically showing the configuration example of FIG. 5(A). [Figure 6] FIG. 6(A) is a top view schematically showing a configuration example of partial removal of the curable resin film, and FIG. 6(B) is a cross-sectional view schematically showing the configuration example of FIG. 6(A). [Figure 7] FIG. 7(A) is a top view schematically showing a configuration example of each piece of the curable resin film, and FIG. 7(B) is a cross-sectional view schematically showing the configuration example of FIG. 7(A). [Figure 8] FIG. 8 is a cross-sectional view schematically showing a method of irradiating laser light from the base material side, removing the removal portion, and forming each piece. [Figure 9] FIG. 9 is a cross-sectional view schematically showing a state where a light-emitting element provided on a base material and each piece on a substrate are opposed to each other. [Figure 10] FIG. 10 is a cross-sectional view schematically showing a state where laser light is irradiated from the substrate side, the light-emitting element is transferred to a predetermined position on the substrate, and arranged. [Figure 11] FIG. 11 is a cross-sectional view schematically showing a state where each piece is arranged on an electrode of a wiring substrate. [Figure 12] FIG. 12 is a cross-sectional view schematically showing a state where a light-emitting element is mounted on each piece arranged in electrode units.

MODE FOR CARRYING OUT THE INVENTION

[0013] Hereinafter, embodiments of the present technology will be described in detail in the following order with reference to the drawings. 1. Display device 2. Method for manufacturing a display device 3. Examples

[0014] <1.Display device> The display device according to this embodiment comprises a plurality of light-emitting elements, a substrate on which the light-emitting elements are arranged in sub-pixel units constituting one pixel, and a cured resin film connecting the plurality of light-emitting elements and the substrate. The cured resin film consists of a plurality of individual pieces, and has exposed portions between the pieces where the substrate is exposed. The exposed portion can also be described as a gap portion where there is no curable resin film contributing to the connection. This makes it possible to obtain excellent light transmittance and aesthetics.

[0015] Figure 1 is a schematic cross-sectional view showing an example of the configuration of a display device. As shown in Figure 1, the display device 10 comprises a plurality of light-emitting elements 20, a substrate 30 on which the light-emitting elements are arranged in subpixel units constituting one pixel, and a cured resin film 40 connecting the plurality of light-emitting elements 20 and the substrate 30.

[0016] The light-emitting element 20 comprises a main body 21, a first conductivity type electrode 22, and a second conductivity type electrode 23, and a so-called flip-chip type LED can be used which has a horizontal structure in which the first conductivity type electrode 22 and the second conductivity type electrode 23 are arranged on the same plane. The main body 21 comprises, for example, a first conductivity type cladding layer made of n-GaN and, for example, In x Al y Ga 1-x-y The device comprises an active layer made of an N layer and a second conductivity type cladding layer made of, for example, p-GaN, and has a so-called double heterostructure. The first conductivity type electrode 22 is formed in a part of the first conductivity type cladding layer by a passivation layer, and the second conductivity type electrode 23 is formed in a part of the second conductivity type cladding layer. When a voltage is applied between the first conductivity type electrode 22 and the second conductivity type electrode 23, carriers concentrate in the active layer and light emission occurs through recombination.

[0017] The size of the light-emitting element 20 may be 200 μm or less, preferably less than 150 μm, more preferably less than 50 μm, and even more preferably less than 20 μm. The thickness of the light-emitting element 20 is, for example, 1 to 20 μm. Here, the size of the light-emitting element 20 is, for example, the larger of the height or width when it is roughly rectangular.

[0018] The light-emitting elements 20 are arranged on the substrate 30 corresponding to each subpixel that makes up one pixel, forming a light-emitting element array. One pixel may be composed of, for example, three subpixels R (red), G (green), and B (blue), four subpixels RGBW (white) and RGBY (yellow), or two subpixels RG and GB.

[0019] Methods for arranging subpixels include, for example, stripe arrangement, mosaic arrangement, and delta arrangement for RGB. Stripe arrangement arranges RGB pixels in vertical stripes, enabling high-resolution images. Mosaic arrangement arranges identical RGB colors diagonally, producing a more natural image than stripe arrangement. Delta arrangement arranges RGB pixels in a triangle, with each dot shifted by half a pitch between fields, resulting in a more natural image display.

[0020] Table 1 shows the estimated lateral pitch between RGB chips, estimated chip size, and estimated electrode size relative to the PPI (Pixels Per Inch) when each RGB chip is arranged horizontally. The minimum chip distance is assumed to be 5 μm, and the estimated RGB distance is maximized when the chips are evenly spaced. These values ​​were calculated as reference values ​​to consider this technology with a clear application in mind.

[0021] [Table 1]

[0022] As shown in Table 1, a chip size of 10 × 20 μm allows for a resolution of up to 500 PPI. Furthermore, a chip size of 7 × 14 μm allows for a resolution of up to 1000 PPI, and by further reducing the chip size, resolutions exceeding 1000 PPI can be achieved. Note that the chip does not necessarily have to be rectangular; it may be square. Also, the chip is not limited to rectangular shapes; it may have similar shapes such as a rhombus.

[0023] The substrate 30 has a circuit pattern for a first conductivity type and a circuit pattern for a second conductivity type on the base material 31, and has a first electrode 32 and a second electrode 33 at positions corresponding to the first conductivity type electrode on the p side and the second conductivity type electrode on the n side, respectively, so that the light-emitting element 20 is arranged in units of subpixels that constitute one pixel. The substrate 30 also forms circuit patterns such as data lines and address lines for matrix wiring, and makes it possible to turn the light-emitting element corresponding to each subpixel that constitutes one pixel on and off. The substrate 30 is preferably a transparent substrate, the base material 31 is preferably a light-transmitting material such as glass or PET (Polyethylene Terephthalate), and the circuit patterns, the first electrode 32 and the second electrode 33 are preferably transparent conductive films such as ITO (Indium-Tin-Oxide), IZO (Indium-Zinc-Oxide), ZnO (Zinc-Oxide), or IGZO (Indium-Gallium-Zinc-Oxide).

[0024] The cured resin film 40 is formed by curing a curable resin film, as described later. The cured resin film 40 consists of a plurality of individual pieces 42, and between the individual pieces 42 of the cured resin film 40 there are exposed portions 30a where the substrate 30 is exposed. The arrangement of the individual pieces 42 on the substrate 30 is not particularly limited as long as the effect of light transmission is obtained, but it is preferable that it be in subpixel units corresponding to the light-emitting elements 20. By arranging the individual pieces 42 in subpixel units, the exposed portions 30a can be increased, and very good light transmission can be obtained. Alternatively, a plurality of closely spaced light-emitting elements 20 in subpixel units may be connected by a single individual piece. This makes it possible to shorten the mounting speed (increase mounting efficiency) and also broaden the range of acceptable specifications depending on the transparency and color conditions of the substrate.

[0025] Furthermore, the individual pieces 42 made of the cured resin film 40 are preferably cured films of an adhesive film, a conductive film containing conductive particles 41, or an anisotropic conductive film (hereinafter, conductive films and anisotropic conductive films will be described as an anisotropic conductive film). This makes it possible to connect multiple light-emitting elements 20 to the substrate 30 even if the light-emitting elements 20 are not provided with connection parts such as solder bumps. Also, if the electrodes of the light-emitting elements 20 are in the form of protrusions, and an electrical connection can be made with the wiring of the substrate 30, the cured resin film 40 does not need to contain conductive particles 41.

[0026] The cured film of an anisotropic conductive film may have conductive particles arranged randomly, but it is preferable that the conductive particles are arranged in a planar direction. By arranging the conductive particles in a planar direction, the particle surface density becomes uniform, and conductivity and insulation properties can be improved. An example of a state in which conductive particles are arranged in a planar direction is a planar lattice pattern having one or more arrangement axes in which conductive particles are arranged at a predetermined pitch in a predetermined direction, such as an orthorhombic lattice, hexagonal lattice, tetragonal lattice, rectangular lattice, or parallelepiped lattice. Furthermore, the anisotropic conductive film may have multiple regions with different planar lattice patterns.

[0027] In addition, the particle surface density of the cured film of the anisotropic conductive film can be appropriately designed according to the electrode size of the light-emitting element 40. The lower limit of the particle surface density is 500 particles / mm 2 or more, 20,000 particles / mm 2 or more, 40,000 particles / mm 2 or more, 50,000 particles / mm 2 or more, and the upper limit of the particle surface density can be 1,500,000 particles / mm 2 or less, 1,000,000 particles / mm 2 or less, 500,000 particles / mm 2 or less, 100,000 particles / mm 2 or less. Thereby, excellent conductivity and insulation can be obtained even when the electrode size of the light-emitting element 20 is small. The particle surface density of the cured film of the anisotropic conductive film is that of the conductive particles when formed into a film during manufacturing. This is the same whether it is measured in the randomly arranged part or in the arranged part. When obtaining the particle number density from a plurality of individual pieces 42, the particle surface density can be obtained from the number of particles and the area obtained by removing the space between the individual pieces 42 from the area including the individual pieces 42 and the space. In some cases, it may be inappropriate to represent the individual pieces by the number density, and in some cases, it may be appropriate to represent them by the occupation area ratio of the particles in one individual piece, the particle diameter, the center distance between particles, and the number.

[0028] The number of conductive particles per individual piece can be appropriately designed according to the electrode size of the light-emitting element 40. The lower limit is, for example, 2 or more, preferably 4 or more, more preferably 10 or more, and the upper limit is 6000 or less, preferably 500 or less, more preferably 100 or less.

[0029] The average transmittance of visible light after the individual pieces are placed (mounted) on the substrate is preferably 20% or more, more preferably 35% or more, and even more preferably 50% or more. This makes it possible to obtain a display device with excellent light transmittance and aesthetics. Even if the substrate is not transparent, the individual pieces can be attached to plain glass or a transparent substrate for evaluation, and the average transmittance can be determined using this as a reference (Ref). The average transmittance of visible light when the light-emitting element is mounted will be lower. When the light-emitting element is mounted, the measurement should be taken when it is not lit. The average transmittance of visible light can be measured, for example, using an ultraviolet-visible spectrophotometer.

[0030] Figure 2 is a schematic cross-sectional view showing an example configuration where the size of the individual chips is small relative to the size of the light-emitting element, Figure 3 is a schematic cross-sectional view showing an example configuration where the size of the individual chips is large relative to the size of the light-emitting element, and Figure 4 is a schematic cross-sectional view showing an example configuration of a conventional display device.

[0031] The size of the individual pieces of the cured resin film 40 relative to the size of the light-emitting element 20 may be smaller than the size of the light-emitting element 20, as shown in Figure 2, provided that conductivity is achieved. Furthermore, the individual pieces of the cured resin film 40 may be arranged not only directly beneath the light-emitting element, but also around its periphery, as shown in Figure 3, provided that the light-transmitting effect of the display device is achieved.

[0032] The amount of protrusion of individual pieces from the light-emitting element 20 is preferably less than 30 μm, more preferably less than 10 μm, and even more preferably less than 5 μm. If there is no protrusion of individual pieces, the amount of protrusion may be zero or negative. This makes it possible to obtain a superior light transmittance compared to the configuration example of a conventional display device 100 in which a cured resin film 140 is provided on the entire surface of the substrate 130 as shown in Figure 4. The amount of protrusion of individual pieces from the light-emitting element 20 is the maximum distance from the periphery of the light-emitting element 20 to the periphery of the individual piece. Alternatively, if one side of the light-emitting element 20 is considered as 1, the amount of protrusion of individual pieces is 0.3 or less, preferably 0.1 or less.

[0033] According to the display device of this embodiment, by having exposed portions 30a where the substrate 30 is exposed between individual pieces of the cured resin film 40, it is possible to obtain excellent light transmittance, conductivity, and insulation that could not be achieved with conventional connections such as ACP, ACF, and NCF, and a high-brightness, high-definition transparent display can be obtained.

[0034] In the above-described embodiment, a display device as a display in which light-emitting elements 20 are arranged in subpixel units was given as an example, but this technology is not limited to this and can also be applied to a light-emitting device as a light source, for example. The light-emitting device comprises a plurality of light-emitting elements, a substrate on which the light-emitting elements are arranged, and a cured resin film connecting the plurality of light-emitting elements and the substrate, wherein the cured resin film consists of a plurality of individual pieces and has exposed portions between the individual pieces where the substrate is exposed. With such a light-emitting device, the number of chips per wafer can be increased because the light-emitting elements 20 are made very small, so the cost can be reduced, and industrial advantages such as thinner and more energy-efficient light-emitting devices can be obtained.

[0035] <2. Manufacturing method of the display device> The method for manufacturing a display device according to this embodiment includes a piece formation step of forming a plurality of pieces made of a curable resin film on a substrate, a bonding step of bonding the plurality of pieces to a substrate, and a mounting step of mounting light-emitting elements on the pieces bonded to the substrate in subpixel units that constitute one pixel. As a result, exposed portions are formed between the pieces where the substrate is exposed, so that excellent light transmittance can be obtained.

[0036] Furthermore, the method for manufacturing the adhesive film according to this embodiment involves irradiating a section of the substrate where a curable resin film has been removed with laser light to form individual pieces made of the curable resin film on the substrate. The adhesive film according to this embodiment comprises a substrate and a plurality of individual pieces made of the curable resin film formed on the substrate, with a distance between the individual pieces being 3 μm or more and 3000 μm or less. Examples of substrates include PET (Poly Ethylene Terephthalate), OPP (Oriented Polypropylene), PMP (Poly-4-methylpentene-1), PTFE (Polytetrafluctuating ethylene oxide), and glass. Preferably, the substrate is one in which at least the surface facing the curable resin film has been peeled off with, for example, a silicone resin. The adhesive film may be wound on a reel, or it may be in the form of a sheet (single leaf) or a plate.

[0037] The following describes the individual piece formation process (A) in which multiple individual pieces are formed, the attachment process (B) in which multiple individual pieces are attached to a substrate, and the mounting process (C) in which a light-emitting element is mounted, with reference to Figures 5 to 11.

[0038] [Individual piece formation process (A)] The method for forming the individual pieces is not particularly limited, and for example, methods such as removing a portion of the curable resin film by laser or cutting, or forming them by printing or inkjet methods can be used. Processing after forming a film on the substrate beforehand is preferable in terms of the degree of freedom in shape design and the ease of the conductive particle placement process.

[0039] Figures 5-7 show examples of forming individual pieces by removing a portion of the curable resin film with a laser. Figure 5(A) is a schematic top view showing an example of the structure of a curable resin film formed over the entire surface of a substrate film. Figure 5(B) is a schematic cross-sectional view showing the structure example of Figure 5(A). Figure 6(A) is a schematic top view showing an example of the structure of partial removal of the curable resin film. Figure 6(B) is a schematic cross-sectional view showing the structure example of Figure 6(A). Figure 7(A) is a schematic top view showing an example of the structure of individual pieces of the curable resin film. Figure 7(B) is a schematic cross-sectional view showing the structure example of Figure 7(A).

[0040] First, as shown in Figures 5(A) and 5(B), a curable resin film 60 is formed on a substrate 50 to prepare a curable resin film substrate. The curable resin film 60 is formed, for example, by known methods such as mixing, coating, and drying.

[0041] (base material) The substrate 50 can be any material that is transparent to laser light, and is preferably quartz glass that has high light transmittance across all wavelengths. Furthermore, when forming individual pieces by printing, inkjet printing, or the like, the substrate 50 can be PET (Polyethylene Terephthalate), PC (Polycarbonate), polyimide, etc.

[0042] (curable resin film) The curable resin film 60 is not particularly limited as long as it hardens with energy such as heat or light, and can be appropriately selected from, for example, thermosetting binders, photocuring binders, and heat / light combined curing binders. As a specific example, a thermosetting binder containing a film-forming resin, a thermosetting resin, and a curing agent will be described. The thermosetting binder is not particularly limited and can be, for example, a thermoanionic polymerization resin composition containing an epoxy compound and a thermoanionic polymerization initiator, a thermocation polymerization resin composition containing an epoxy compound and a thermocation polymerization initiator, or a thermoradical polymerization resin composition containing a (meth)acrylate compound and a thermoradical polymerization initiator. Note that (meth)acrylate compounds include both acrylic monomers (oligomers) and methacrylic monomers (oligomers).

[0043] Among these thermosetting binders, it is preferable that the thermosetting resin contains an epoxy compound and the curing agent is a thermal cationic polymerization initiator. This suppresses the curing reaction when forming individual pieces with laser light, and allows for rapid curing by heat during thermal bonding. In the following, a specific example will be given of a thermal cationic polymerization resin composition containing a film-forming resin, an epoxy compound, and a thermal cationic polymerization initiator.

[0044] The film-forming resin is, for example, a high molecular weight resin with an average molecular weight of 10,000 or more, and from the viewpoint of film formation, an average molecular weight of about 10,000 to 80,000 is preferred. Examples of film-forming resins include various resins such as butyral resin, phenoxy resin, polyester resin, polyurethane resin, polyester urethane resin, acrylic resin, and polyimide resin, which may be used individually or in combination of two or more types. Among these, butyral resin is preferred from the viewpoint of film formation state and connection reliability. The content of the film-forming resin is preferably 20 to 70 parts by mass, more preferably 30 to 60 parts by mass or less, and even more preferably 45 to 55 parts by mass, per 100 parts by mass of the thermosetting binder.

[0045] The epoxy compound is not particularly limited as long as it is an epoxy compound having one or more epoxy groups in its molecule. For example, it may be a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, or a urethane-modified epoxy resin. Among these, hydrogenated bisphenol A glycidyl ether is preferably used. A specific example of hydrogenated bisphenol A glycidyl ether is the product "YX8000" manufactured by Mitsubishi Chemical Corporation. The epoxy compound content is preferably 30 to 60 parts by mass, more preferably 35 to 55 parts by mass or less, and even more preferably 35 to 45 parts by mass, per 100 parts by mass of the thermosetting binder.

[0046] As the thermal cationic polymerization initiator, known thermal cationic polymerization initiators for epoxy compounds can be used. For example, those that generate an acid capable of cationic polymerization of cationic polymer-type compounds upon heating, such as known iodonium salts, sulfonium salts, phosphonium salts, ferrocenes, etc., can be used. Among these, aromatic sulfonium salts that exhibit good latent properties with respect to temperature are preferably used. A specific example of an aromatic sulfonium salt-based polymerization initiator is, for example, the product name "SI-60L" manufactured by Sanshin Chemical Industry Co., Ltd. The content of the thermal cationic polymerization initiator is preferably 1 to 20 parts by mass, more preferably 5 to 15 parts by mass or less, and even more preferably 8 to 12 parts by mass, per 100 parts by mass of the thermosetting binder.

[0047] In addition, other additives that may be incorporated into the thermosetting binder, as needed, include rubber components, inorganic fillers, silane coupling agents, diluent monomers, fillers, softeners, colorants, flame retardants, thixotropic agents, etc.

[0048] The rubber component is not particularly limited as long as it is an elastomer with high cushioning (shock absorption) properties. Specific examples include acrylic rubber, silicone rubber, butadiene rubber, and polyurethane resin (polyurethane elastomer). Inorganic fillers such as silica, talc, titanium dioxide, calcium carbonate, and magnesium oxide can be used. Inorganic fillers may be used alone or in combination of two or more types.

[0049] Furthermore, the curable resin film 60 is preferably an anisotropic conductive film further containing conductive particles. The conductive particles can be appropriately selected from those used in known anisotropic conductive films. Examples include metal particles such as nickel, copper, silver, gold, palladium, and solder, or metal-coated resin particles in which the surface of resin particles such as polyamide and polybenzoguanamine is coated with a metal such as nickel or gold. This enables conductivity even when connection points such as solder bumps are not provided on the chip component.

[0050] Anisotropic conductive films are preferably constructed by arranging conductive particles in a planar direction. This arrangement of conductive particles results in a uniform particle density, improving conductivity and insulation. Furthermore, anisotropic conductive films can be configured to have a region where conductive particles are concentrated at positions corresponding to electrodes, and a region where conductive particles are absent at other positions. From the viewpoint of capture, the concentration region is preferably at least 0.8 times the electrode size, more preferably at least 1.0 times, and from the viewpoint of reducing conductive particles, it is preferable that it be at least 1.2 times the electrode size, more preferably 1.5 times. The removed portion can be reused for quality control or inspection purposes.

[0051] Furthermore, the particle surface density of the anisotropic conductive film can be appropriately designed according to the electrode size of the light-emitting element 40, similar to the cured film, and the lower limit of the particle surface density is 500 particles / mm². 2 More than 20000 pieces / mm 2 More than 40000 pieces / mm 2 More than 50000 pieces / mm 2The above can be achieved, and the upper limit of the particle surface density is 1,500,000 particles / mm³. 2 Below 1000000 pieces / mm 2 Below 500000 pieces / mm 2 Below 100000 pieces / mm 2 The following can be achieved. This makes it possible to obtain excellent conductivity and insulation even when the electrode size of the light-emitting element 20 is small. The particle surface density of the cured film of the anisotropic conductive film is that of the portion where the conductive particles are arranged when the film is formed during manufacturing. When determining the particle number density from multiple pieces, the particle surface density can be determined from the area obtained by subtracting the space between pieces from the area including the pieces and the space between them, and the number of particles.

[0052] The particle size of the conductive particles is not particularly limited, but the lower limit of the particle size is preferably 1 μm or more, and the upper limit of the particle size is preferably 50 μm or less, and more preferably 20 μm or less, from the viewpoint of the capture efficiency of conductive particles in the connecting structure. Depending on the size of the electrode, it may be required to be less than 3 μm, preferably less than 2.5 μm. The particle size of the conductive particles can be the value measured by an image-type particle size analyzer (for example, FPIA-3000: manufactured by Malvern). The number of particles is preferably 1000 or more, preferably 2000 or more.

[0053] The lower limit of the thickness of the curable resin film 60 may be, for example, 60% or more of the particle diameter of the conductive particles, or 90% or more to accommodate relatively small particle diameters, but preferably it can be 1.3 times or more of the conductive particle diameter or 3 μm or more. The upper limit of the thickness of the connecting film can be, for example, 20 μm or less or 3 times or less of the particle diameter of the conductive particles, preferably 2 times or less. Furthermore, the curable resin film 60 may be laminated with an adhesive layer or tack layer that does not contain conductive particles, and the number of layers and the lamination surface can be appropriately selected according to the target and purpose. In addition, the same insulating resin as the curable resin film 60 can be used for the adhesive layer or tack layer. The film thickness can be measured using a known micrometer or digital thickness gauge. The film thickness can be determined by measuring at, for example, 10 or more locations and averaging the results.

[0054] The tack force of the front and back surfaces of the curable resin film 60, measured by probe method, was, for example, 1.0 kPa (0.1 N / cm²) on at least one of the front and back surfaces when the probe pressing speed was 30 mm / min, the pressing force was 196.25 gf, the pressing time was 1.0 sec, the peeling speed was 120 mm / min, and the measurement temperature was 23°C ± 5°C. 2 It can be set to 1.5 kPa (0.15 N / cm²) or higher. 2 It is preferable to set it to 3 kPa (0.3 N / cm²) or higher, 2 It is more preferable that the value is higher than the specified value. The measurement can be performed, for example, by attaching one side of a curable resin film 60 of 3 cm x 3 cm or larger to a piece of plain glass (for example, 0.3 mm thick) and measuring the tack force of the other side. By having the tack force of at least one of the front and back sides of the curable resin film 60 within the above range, the adhesion of the curable resin film 60 to the substrate 50 can be maintained, and the adhesion of multiple individual pieces to the substrate 30 can be maintained in the adhesion process (B) described later.

[0055] Next, as shown in Figures 6(A) and 6(B), laser light is irradiated onto the removal section 61 of the curable resin film 60, and individual pieces 62 made of the curable resin film are formed on the substrate 50, as shown in Figures 7(A) and 7(B).

[0056] The dimensions (length × width) of each individual piece 62 are appropriately set according to the dimensions of the light-emitting element 20, which is a chip component. The ratio of the area of ​​each individual piece 62 to the area of ​​the light-emitting element 20 is preferably 0.5 to 5.0, more preferably 0.5 to 4.0, and even more preferably 0.5 to 2.0. The thickness of each individual piece 62 is preferably 2 to 10 μm, more preferably 3 to 8 μm or less, and even more preferably 4 to 6 μm or less. It is preferable that all individual pieces have the same dimensions, but multiple types may exist to increase the design flexibility of the connection structure. This makes it possible to obtain a connection structure with excellent light transmittance, conductivity, and insulation properties that could not be achieved with conventional connections such as ACP, ACF, NCF, and adhesives.

[0057] Furthermore, the distance between individual pieces 62 arranged at predetermined positions on the substrate 50 is preferably 3 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. The upper limit of the distance between individual pieces is preferably 3000 μm or less, more preferably 1000 μm or less, and even more preferably 500 μm or less. If the distance between individual pieces is too small, it becomes difficult to obtain excellent light transmittance and aesthetics, and if the distance between individual pieces is too large, it becomes difficult to obtain a display device with high PPI.

[0058] Figure 8 is a schematic cross-sectional view illustrating a method for removing the removal portion 61 and forming individual pieces 62 by irradiating the substrate with laser light from the substrate side. For example, a LIFT (Laser Induced Forward Transfer) device can be used to remove the removal portion 61. The LIFT device includes, for example, a telescope that makes the pulsed laser light emitted from the laser device into parallel light, a shaping optical system that uniformly shapes the spatial intensity distribution of the pulsed laser light that has passed through the telescope, a mask that allows the pulsed laser light shaped by the shaping optical system to pass through in a predetermined pattern, a field lens located between the shaping optical system and the mask, and a projection lens that reduces and projects the laser light that has passed through the pattern on the mask onto the donor substrate, and holds the curable resin film substrate, which is the donor substrate, on a donor stage.

[0059] As the laser device, for example, an excimer laser that emits laser light with a wavelength of 180 nm to 360 nm can be used. The oscillation wavelengths of the excimer laser are, for example, 193, 248, 308, and 351 nm, and can be suitably selected from these oscillation wavelengths according to the light absorption properties of the material of the curable resin film 60. In addition, if a release material is provided between the substrate 50 and the curable resin film 60, it can be suitably selected according to the light absorption properties of the material of the release material.

[0060] The mask uses a pattern in which a predetermined number of windows of a predetermined size are formed at a predetermined pitch so that the projection at the interface between the substrate 50 and the curable resin film 60 results in a desired laser beam pattern. The mask is patterned, for example, by chrome plating, so that the unplated window areas transmit the laser beam, while the chrome-plated areas block the laser beam.

[0061] The light emitted from the laser device enters the telescopic optical system and propagates to the shaping optical system beyond it. The laser light is adjusted by the telescopic optical system so that it is approximately parallel at any position within the X-axis movement range of the donor stage just before it enters the shaping optical system. Therefore, it always enters the shaping optical system at approximately the same size and angle (perpendicular).

[0062] The laser light that has passed through the shaping optical system enters the mask via a field lens that, in combination with the projection lens, constitutes an image-side telecentric reduction projection optical system. The laser light that has passed through the mask pattern has its propagation direction changed vertically downward by the reflected light mirror and enters the projection lens. The laser light emitted from the projection lens enters from the substrate 50 side and is accurately projected onto a predetermined position on the curable resin film 60 formed on its surface (bottom surface) at a reduced size of the mask pattern.

[0063] There are no particular restrictions on the laser energy intensity used in laser irradiation, and it can be appropriately selected according to the purpose, but it is preferably between 5% and 100%, and more preferably between 5% and 50%. Laser energy intensity refers to a laser irradiation intensity of 10,000 mJ / cm². 2 This is the intensity expressed as a percentage of the output power, with the value set to 100. For example, a laser energy intensity of 10% means a laser irradiation intensity of 1,000 mJ / cm². 2 It means...

[0064] Furthermore, there are no particular restrictions on the number of laser irradiations, and they can be appropriately selected according to the purpose, but 1 to 10 times is preferable. The total laser irradiation intensity during laser irradiation is 500 mJ / cm². 2 More than 10,000mJ / cm 2 The following is preferable: 1,000 mJ / cm² 2 More than 5,000mJ / cm 2 The following is more preferable. Here, the total laser irradiation intensity is the irradiation intensity calculated as the sum of the laser irradiation intensities of n laser irradiations during the laser irradiation. Here, "n" indicates the number of laser irradiations.

[0065] For removing the anisotropic conductive layer, pulsed laser ablation devices such as the LMT-200 (Toray Engineering Co., Ltd.), C.MSL-LLO1.001 (Takano Corporation), and DFL7560L (DISCO Corporation) can be used.

[0066] By using such a lifting device, a shock wave can be generated in the curable resin film 60 irradiated with laser light at the interface between the substrate 50 and the curable resin film 60, causing the removal portion 61 to peel off and be removed from the substrate 50, and allowing the individual pieces 62 of the curable resin film 60 to be arranged on the substrate 50 with high precision and efficiency.

[0067] Depending on the method, if the removal portion 61 on the substrate 50 is removed, "peeling" may occur on the individual pieces 62. If the portion where the resin layer has become doubled due to peeling is attached to the electrode portion, connection failure may occur. Also, the distortion of the shape of the individual pieces 62 may also be a cause of adhesion failure. It is preferable that the peeled portion of the individual pieces 62 is less than 20% of the predetermined area of ​​the individual pieces 62. Also, when attaching the individual pieces 62 to the substrate 30, "peeling" may occur on the periphery of the individual pieces 62, but in this case as well, it is preferable that the peeled portion of the individual pieces 62 is less than 20% of the predetermined area of ​​the individual pieces 62. This can suppress connection failure and adhesion failure. Also, it is preferable that the predetermined shape of the individual pieces 62 is rectangular. If the shape of the individual pieces 62 is distorted, the dimensions can be determined by converting the film area to a rectangle. The dimensions of one side of the individual pieces 62 can be approximated from the original shape. Furthermore, if a piece 62 is peeled back, it may be approximated as a rectangle based on its unpeeled shape. If there are multiple pieces 62, the predetermined area of ​​the unpeeled pieces 62 can be used as 100% for calculation. These can be determined by the observation method described later.

[0068] [Pasting process (B)] In the attachment process (B), multiple individual pieces 62 arranged on the substrate 50 are attached to the substrate 30. The method of attaching the individual pieces 62 is not particularly limited, and one example is to temporarily attach the individual pieces 62 from the substrate 50 to the substrate 30 and then transfer them.

[0069] In the individual piece formation step (A), if individual pieces are formed on the substrate 50 in subpixel units, it is preferable in the attachment step (B) to transfer the individual pieces 62 on the substrate 50 onto the substrate 30. By aligning the substrate 50 and the substrate 30 and transferring the pieces, the individual pieces 62 can be arranged on the substrate 30 in subpixel units. Furthermore, if the size of the substrate 30 is larger than the size of the substrate 50, the individual pieces 62 can be arranged in subpixel units within the screen area of ​​the substrate 30 by transferring the individual pieces 62 on the substrate 50 onto the substrate 30 multiple times.

[0070] The average visible light transmittance of the substrate 30 to which the multiple pieces 62 are attached after the attachment process (B) is preferably 20% or more, more preferably 35% or more, and even more preferably 50% or more. This makes it possible to obtain a display device with excellent light transmittance and aesthetic appeal.

[0071] [Implementation Process (C)] In the mounting process (C), first, the light-emitting elements 20 are mounted on individual pieces 62 of the substrate 30. There are no particular limitations on the method of mounting the light-emitting elements 20 to the substrate 30, but examples include a method of directly transferring and placing the light-emitting elements 20 from the wafer substrate to the substrate 30 using the laser lift-off method (LLO method), or a method of transferring and placing the light-emitting elements 20 from the transfer substrate to the substrate 30 using a transfer substrate to which the light-emitting elements 20 have been previously attached.

[0072] The process of irradiating the light-emitting elements onto the individual pieces by laser light will be described below with reference to Figures 9 and 10. Figure 9 is a schematic cross-sectional view showing the state in which the light-emitting elements provided on the substrate and the individual pieces on the substrate are facing each other, and Figure 10 is a schematic cross-sectional view showing the state in which laser light is irradiated from the substrate side, transferring the light-emitting elements to predetermined positions on the substrate and arranging them.

[0073] As shown in Figure 9, first, a chip component substrate 70 on which the light-emitting element 20 is provided is placed opposite a piece 62 made of a curable resin film on a substrate 30.

[0074] The chip component substrate 70 comprises a base material 71, a release material 72, and a light-emitting element 20, with the light-emitting element 20 attached to the surface of the release material 72. The substrate 71 can be any material that is transparent to laser light, and is preferably quartz glass having high light transmittance across all wavelengths. The release material 72 can be any material that has absorption characteristics with respect to the wavelength of laser light, and generates a shock wave when irradiated with laser light, which propels the light-emitting element 20 toward the substrate 30. Polyimide can be used as an example of the release material 72.

[0075] The distance D between the light-emitting element 20 and the individual pieces 62 is, for example, 10 to 100 μm. The width W20 of the light-emitting element 20 is preferably less than 150 μm, more preferably less than 50 μm, and even more preferably less than 20 μm. The thickness T20 of the light-emitting element 20 is, for example, 1 to 20 μm. The thickness T12 of the release material 72 is, for example, 1 μm or more. The dimensions (length × width) of the individual pieces 62 are appropriately set according to the dimensions of the light-emitting element 20, and it is preferable that the area ratio of the individual pieces 62 to the light-emitting element 20 is 0.5 to 5.0. The thickness T62 of the individual pieces 62 is preferably 2 to 10 μm, more preferably 3 to 8 μm or more, and even more preferably 4 to 6 μm or less. The distance D between the light-emitting element 20 and the individual pieces 62 can be observed and confirmed, for example, using an optical microscope, laser microscope, white light microscope, etc. Conductive particle diameter, conductive particle arrangement shape, and inter-conductive particle distance can also be determined in the same way.

[0076] Next, as shown in Figure 10, laser light 80 is irradiated from the substrate 71 side to transfer and arrange the light-emitting elements 20 onto the individual pieces 62 of the substrate 30. For the transfer of the light-emitting elements 20, for example, the aforementioned lift device can be used, in which the chip component substrate 70, which is the donor substrate, is held on the donor stage, and the substrate 30, which is the receptor substrate, is held on the receptor stage. The laser light 80 that has passed through the mask pattern is incident from the substrate 71 side and is accurately projected onto predetermined positions on the release material 72 formed on its surface (bottom surface) at a reduced size of the mask pattern. At the interface between the substrate 71 and the release material 72, a shock wave is generated in the release material 72 by irradiation with laser light 80, causing multiple light-emitting elements 20 to peel off from the substrate 71 and be lifted toward the substrate 30, landing on the individual pieces 62 of the substrate 30. This suppresses the occurrence of defects such as displacement, deformation, breakage, and detachment of the light-emitting elements 20, and enables the transfer and arrangement of the light-emitting elements 20 with high precision and efficiency, thereby shortening the cycle time.

[0077] Next, the light-emitting elements 20 arranged at predetermined positions on the substrate 30 are thermocompressed onto the substrate via individual pieces 62. As a method for thermocompressing the light-emitting elements 20 onto the substrate 30, a thermocompression bonding method used for known curable resin films can be appropriately selected and used. For example, the thermocompression bonding conditions are a temperature of 150°C to 260°C, a pressure of 1 MPa to 60 MPa, and a time of 5 seconds to 300 seconds. A cured resin film is formed when the curable resin film hardens. Furthermore, if the conductive particles are solder particles, they may be connected by reflow soldering.

[0078] According to the manufacturing method of the display device of this embodiment, the light-emitting element 20 can be connected to the substrate 30 with exposed portions 30a provided between the individual pieces of the cured resin film 40, where the substrate 30 is exposed. This makes it possible to obtain excellent light transmittance, conductivity, and insulation that could not be achieved with conventional connections such as ACP, ACF, NCF, and adhesives, and to obtain a high-brightness, high-definition transparent display.

[0079] In the above-described embodiment, a method for manufacturing a display device as a display in which light-emitting elements 20 are arranged in subpixel units was given as an example. However, this technology is not limited to this, and can also be applied to a method for manufacturing a light-emitting device as a light source, for example. The method for manufacturing a light-emitting device includes a piece formation step of removing a portion of a curable resin film formed on a substrate and forming a plurality of individual pieces made of curable resin film on the substrate, a bonding step of bonding the plurality of individual pieces onto a substrate, and a mounting step of mounting light-emitting elements on the individual pieces bonded to the substrate. According to such a method for manufacturing a light-emitting device, it is possible to reduce costs and obtain industrial advantages such as making the light-emitting device thinner and saving energy.

[0080] Furthermore, in the above-described embodiment, the individual pieces are formed in the individual piece formation step (A) in units of light-emitting elements, i.e., in units of subpixels. However, the invention is not limited to this, and for example, they may be formed in units of electrodes of light-emitting elements.

[0081] When individual pieces are formed in units of electrodes of a light-emitting element, the dimensions (length × width) of the individual pieces are appropriately set according to the dimensions of the electrodes of the light-emitting element. Similar to when individual pieces are formed in units of light-emitting elements, the ratio of the area of ​​the individual piece to the area of ​​the electrode is preferably 0.5 to 5.0, more preferably 0.5 to 4.0, and even more preferably 0.5 to 2.0. The thickness of the individual pieces is preferably 2 to 10 μm, more preferably 3 to 8 μm or less, and even more preferably 4 to 6 μm or less.

[0082] Figure 11 is a schematic cross-sectional view showing the individual pieces arranged on the electrodes of a wiring board, and Figure 12 is a schematic cross-sectional view showing the light-emitting element mounted on the individual pieces arranged in electrode units. When individual pieces are formed in the individual piece formation process (A) in electrode units of the light-emitting element 20, in the attachment process (B), the individual pieces 63 are attached to the electrodes of the substrate 30. That is, as shown in Figure 11, the first individual piece 63A and the second individual piece 63B are attached to the first electrode 32 and the second electrode 33, which correspond to, for example, the first conductivity type electrode 22 on the p side and the second conductivity type electrode 23 on the n side of the light-emitting element 20, respectively. Then, as shown in Figure 12, in the mounting process (C), the light-emitting element 20 is mounted on the individual pieces 63 arranged in electrode units on the wiring board 30. This further improves the transparency of the display device.

[0083] Furthermore, in the individual piece formation process (A), when a portion of the curable resin film is removed by a laser to form individual pieces, the curable resin film may be pre-treated to efficiently remove the unnecessary portion of the curable resin film. Examples of pre-treatment include cuts in the shape of individual pieces, such as light-emitting units or electrode units, and grid-like cuts where multiple vertical cuts and multiple horizontal cuts intersect. The cuts can be made using mechanical methods, chemical methods, lasers, etc. Note that the cuts do not need to be deep enough to reach the substrate, and half-cuts are acceptable. This helps to suppress the occurrence of peeling of the individual pieces.

[0084] Furthermore, in the bonding process (B), the lifting device described above may be used to transfer the multiple individual pieces 62 of the light-emitting units or the multiple individual pieces 63 of the electrode units arranged on the substrate 50 to the substrate 30. By using the lifting device, a shock wave is generated at the interface between the substrate and the individual pieces when laser light is irradiated onto the individual pieces, peeling the individual pieces away from the substrate and lifting them toward the substrate 30, thereby landing the individual pieces at predetermined positions on the substrate 30 with high precision. This makes it possible to shorten the cycle time.

[0085] Alternatively, using the aforementioned lifting device, multiple individual pieces 62 of light-emitting units or multiple individual pieces 63 of electrode units arranged on the substrate 50 may be transferred to the light-emitting units 20 arranged on the chip component substrate 70, and the light-emitting units 20 with the transferred pieces may be re-transferred onto the substrate 30. This can shorten the cycle time. [Examples]

[0086] <3. Examples> In this example, the dimensions of the connecting material were varied relative to the dimensions of the chip during mounting, and the visible light transmittance, amount of adhesive overflow, and the amount of alignment deviation before and after mounting were evaluated. Conductivity and insulation resistance were also evaluated. Note that this technology is not limited to these examples.

[0087] [Example 1] A resin film was obtained by mixing, coating, and drying (60°C - 3 min) a mixture containing 50 wt% polyvinyl butyral resin (product name: KS-10, manufactured by Sekisui Chemical Co., Ltd.), 40 wt% hydrogenated bisphenol A glycidyl ether (product name: YX8000, manufactured by Mitsubishi Chemical Corporation), and 10 wt% cationic polymerization initiator (product name: SI-60L, manufactured by Sanshin Chemical Industry Co., Ltd.).

[0088] Conductive particles (average particle size 2.2 μm, resin core metal coated fine particles, 0.2 μm thick Ni plating, manufactured by Sekisui Chemical Co., Ltd.) were pressed onto the obtained resin film using the method described in Patent No. 6187665, so that the conductive particles were approximately aligned with one interface of the resin film, resulting in a thickness of 4.0 μm and a particle surface density of 58,000 particles / mm². 2 An anisotropic conductive film was obtained. The arrangement of conductive particles in the anisotropic conductive film in a plan view was such that it was arranged in a hexagonal lattice.

[0089] A portion of an anisotropic conductive film on glass was removed by laser ablation, forming individual pieces of anisotropic conductive film with a thickness of 4.0 μm and an area ratio of 15 × 30 μm (area ratio 1.0) on the glass in a predetermined arrangement. The laser irradiation conditions were as follows. Laser type: YAG Laser Laser wavelength: 266nm Laser energy intensity: 10% Number of laser treatments: 1

[0090] Then, individual pieces were temporarily attached and arranged on a glass substrate in a predetermined position so that 15 × 30 μm microchips, resembling microLEDs, would be equivalent to 110 ppi (chip area ratio: 2.46%, total number of chips: 12,288) within a 1.5 × 1.5 cm area. After that, the microchips were thermocompressed (temperature 170°C, pressure 30 MPa, time 30 sec) via the individual pieces to obtain a mounted assembly.

[0091] [Example 2] A mounting body was obtained in the same manner as in Example 1, except that individual pieces of an anisotropic conductive film with a thickness of 4.0 μm and an area ratio of 10.6 × 21.2 μm (area ratio of 0.5) were formed on glass in a predetermined arrangement.

[0092] [Example 3] A mounting body was obtained in the same manner as in Example 1, except that individual pieces of an anisotropic conductive film with a thickness of 4.0 μm and an area ratio of 33.5 × 67.1 μm (area ratio of 5.0) were formed on glass in a predetermined arrangement.

[0093] [Example 4] Thickness 6.0 μm, particle surface density 58,000 particles / mm² 2 After obtaining the anisotropic conductive film, a mounting body was obtained in the same manner as in Example 1, except that individual pieces of the anisotropic conductive film, each 6.0 μm thick and 15 × 30 μm in size, were formed on glass in a predetermined arrangement.

[0094] [Example 5] Thickness 4.0 μm, particle surface density 100,000 particles / mm² 2 After obtaining the anisotropic conductive film, a mounting body was obtained in the same manner as in Example 1, except that individual pieces of the anisotropic conductive film, each 4.0 μm thick and 15 × 30 μm in size, were formed on glass in a predetermined arrangement.

[0095] [Example 6] A resin composition is prepared by mixing 50 wt% polyvinyl butyral resin (product name: KS-10, manufactured by Sekisui Chemical Co., Ltd.), 40 wt% hydrogenated bisphenol A glycidyl ether (product name: YX8000, manufactured by Mitsubishi Chemical Corporation), and 10 wt% cationic polymerization initiator (product name: SI-60L, manufactured by Sanshin Chemical Industry Co., Ltd.), with a particle surface density of 58,000 particles / mm². 2 Conductive particles (the same conductive particles as in Example 1) were mixed together, coated, and dried (60°C - 3 min) to obtain an anisotropic conductive film with a thickness of 4.0 μm. Then, a mounting body was obtained in the same manner as in Example 1, except that individual pieces of the anisotropic conductive film, each 4.0 μm thick and 15 × 30 μm in size, were formed on glass in a predetermined arrangement.

[0096] [Comparative Example 1] A resin composition was prepared by mixing 95 wt% hydrogenated bisphenol A glycidyl ether (product name: YX8000, manufactured by Mitsubishi Chemical Corporation) and 5 wt% aluminum chelate latent curing agent. Conductive particles (the same conductive particles as in Example 1) and titanium dioxide (10 vol%) were dispersed in this mixture to obtain an anisotropic conductive paste.

[0097] An anisotropic conductive paste was applied to the entire surface of the glass to obtain an anisotropic conductive film with a thickness of 4.0 μm. Then, a 15 × 30 μm microchip, modeled after a micro-LED, was thermocompressed onto the anisotropic conductive film within a 1.5 × 1.5 cm area to achieve a resolution equivalent to 110 ppi, thereby obtaining a mounted assembly.

[0098] [Comparative Example 2] A resin composition is prepared by mixing 50 wt% polyvinyl butyral resin (product name: KS-10, manufactured by Sekisui Chemical Co., Ltd.), 40 wt% hydrogenated bisphenol A glycidyl ether (product name: YX8000, manufactured by Mitsubishi Chemical Corporation), and 10 wt% cationic polymerization initiator (product name: SI-60L, manufactured by Sanshin Chemical Industry Co., Ltd.), with a particle surface density of 58,000 particles / mm². 2 Conductive particles (the same conductive particles as in Example 1) were mixed together, coated, and dried (60°C - 3 min) to obtain an anisotropic conductive film with a thickness of 4.0 μm. Then, the anisotropic conductive film was attached to the entire surface of the glass to obtain an anisotropic conductive film with a thickness of 4.0 μm. After that, a 15 × 30 μm microchip, modeled after a micro-LED, was thermocompressed (temperature 170°C - pressure 30 MPa - time 30 sec) via the anisotropic conductive film to obtain a mounted body, so that the microchip would be equivalent to 110 ppi within a 1.5 × 1.5 cm area.

[0099] [Comparative Example 3] A resin film is bonded to a substrate on which conductive particles (the same conductive particles as in Example 1) are arranged in a predetermined pattern. The conductive particles are then transferred to the resin film, resulting in a thickness of 4.0 μm and a particle density of 58,000 particles / mm². 2 An anisotropic conductive film was obtained. The anisotropic conductive film was then applied to the entire surface of the glass to obtain an anisotropic conductive film with a thickness of 4.0 μm. A 15 × 30 μm microchip, modeled after a microLED, was then thermocompressed (temperature 170°C - pressure 30 MPa - time 30 sec) via the anisotropic conductive film to obtain a mounted assembly, so that the microchip had an equivalent of 110 ppi within a 1.5 × 1.5 cm area.

[0100] [Evaluation of visible light transmittance] Using a transmittance measuring device (Shimadzu UV-2450, JIS Z 8729, light source Type-C, field of view 2°), the average transmittance of visible light (wavelength 400-700 nm) was measured for quartz glass (thickness 0.4 mm) equipped with individual piece arrangements (Examples 1-6), anisotropic conductive films (Comparative Examples 2 and 3), or anisotropic conductive films coated with anisotropic conductive paste (Comparative Example 1). The visible light transmittance was evaluated with a rating from A to D according to the average visible light transmittance. A rating of C or higher is desirable for the visible light transmittance evaluation. A: 50% or more B: 35% or more, less than 50% C: 20% to less than 35% D: Less than 20%

[0101] [Evaluation of overhang amount] After mounting a microchip that mimicked a micro-LED, the external appearance of the microchip was inspected using a metallurgical microscope, and the amount of adhesive protruding from the microchip was measured. The amount of adhesive protrusion was evaluated using the following criteria from A to D. A rating of C or higher is desirable for the amount of adhesive protrusion. A: Less than 5 μm B: 5 μm or more and less than 10 μm C: 10 μm or more and less than 30 μm D:30μm or more

[0102] [Evaluation of alignment discrepancies before and after implementation] Microchips, modeled after micro-LEDs, were temporarily fixed to an anisotropic conductive film on glass. Their appearance was then examined using a metallurgical microscope, and after chip mounting, the appearance was again examined from the microchip side using a metallurgical microscope. Alignment deviations were checked before and after mounting, and if any, the amount of deviation was measured. Chip deviation was evaluated using a rating system from A to D, depending on the amount of deviation. A rating of C or higher is desirable. A: Less than 0.1 μm B: 0.1 μm or more and less than 1 μm C: 1 μm or more and less than 2 μm D:2μm or more

[0103] [Evaluation of conductivity and insulation resistance] Using the respective connecting materials from Examples 1-6 and Comparative Examples 1-3, an evaluation IC chip (outer dimensions: 5mm x 5mm, thickness: 0.15mm, electrode size: 15μm x 30μm, electrode: Au, protrusion height: 10μm) was thermocompressed (temperature 170℃ - pressure 30Mpa - time 30sec) onto an evaluation glass substrate (outer dimensions: 28mm x 65mm, thickness: 0.5mm, electrode: ITO / MoNb wiring) to obtain a connected body.

[0104] The continuity resistance of the connections was measured using the four-terminal method. The continuity resistance was evaluated using the following criteria A to D, depending on the value of the continuity resistance. A continuity resistance evaluation of C or higher is desirable. A: Less than 30Ω B: 30Ω or more and less than 100Ω C: 100Ω or more and less than 300Ω D: 300Ω or more

[0105] The insulating space between electrodes (7 μm) was measured at 100 locations, and 10 7 A value of Ω or less was counted as a short circuit. Insulation resistance was evaluated using a classification from A to D based on the number of short circuits. A C or higher rating is desirable for conductivity resistance. A: There are 0 short circuits. B: There is one short circuit. C: There are two short circuits. D: Three or more short circuits

[0106] Table 1 shows the evaluation results for visible light transmittance, adhesive overflow, chip displacement, conductivity resistance, and insulation resistance for Examples 1-6 and Comparative Examples 1-3.

[0107] [Table 2]

[0108] As shown in Table 1, in Comparative Example 1 using ACP, due to the paste nature, the resin flow during mounting was large, resulting in the presence of ACP adhesive resin and conductive particles between the microchip pitches, which hindered light transmission and prevented good transparency from being obtained. In addition, in Comparative Example 1 using ACP, the electrode size of the evaluation IC chip was small, so good evaluation of conduction resistance and insulation resistance could not be obtained.

[0109] In Comparative Examples 2 and 3, which used ACF, the ACF was attached to the entire surface of the glass substrate to mount the microchip. Similar to Comparative Example 1, the adhesive resin and conductive particles of the ACF were present between the microchip pitches, hindering light transmission and resulting in poor transparency. Furthermore, in Comparative Example 2, which used randomly arranged ACF, the small electrode size of the evaluation IC chip prevented a good evaluation of conduction resistance and insulation resistance.

[0110] On the other hand, Examples 1-6, which used individual pieces of anisotropic conductive film, had exposed areas where the glass substrate was exposed between the pitches of the microchip, resulting in high transmittance of visible light and a good evaluation of the amount of overflow. Furthermore, the particle density in the arrangement was 40,000 to 80,000 particles / mm². 2 Examples 1 to 4, which used individual pieces, yielded a good evaluation of insulation resistance. [Explanation of Symbols]

[0111] 10 Display device, 20 Light-emitting element, 21 Main body, 22 First conductive electrode, 23 Second conductive electrode, 30 Substrate, 30a Exposed part, 31 Base material, 32 First electrode, 33 Second electrode, 40 Cured resin film, 41 Conductive particles, 42 Pieces, 50 Base material, 60 Curable resin film, 61 Removal part, 62 Pieces, 63 Pieces, 70 Chip component substrate, 71 Base material, 72 Release material, 80 Laser light, 100 Display device, 120 Light-emitting element, 121 Main body, 130 Substrate, 131 Base material, 140 Cured resin film, 141 Conductive particles

Claims

1. Multiple light-emitting elements, A substrate on which light-emitting elements are arranged in units of subpixels that constitute one pixel, The system comprises a cured resin film connecting the plurality of light-emitting elements and the substrate, A display device in which the cured resin film consists of a plurality of individual pieces, and the substrate is exposed between the individual pieces.

2. The display device according to claim 1, wherein the individual pieces are arranged on the substrate in subpixel units.

3. The display device according to claim 1 or 2, wherein the amount of the individual pieces protruding from the light-emitting element is less than 30 μm.

4. The display device according to any one of claims 1 to 3, wherein the substrate is a transparent substrate.

5. The display device according to any one of claims 1 to 4, wherein the size of the light-emitting element is less than 200 μm.

6. The display device according to any one of claims 1 to 5, wherein the cured resin film contains conductive particles, and the conductive particles are arranged in a planar direction.

7. A piece formation step involves removing a portion of the curable resin film formed on a substrate and forming a plurality of individual pieces made of the curable resin film on the substrate, The process of attaching the plurality of pieces onto the substrate, A mounting step is to mount light-emitting elements on individual pieces attached to the substrate, in units of subpixels that constitute one pixel. A method for manufacturing a display device having [a certain feature].

8. In the individual piece formation step, the individual pieces are formed on the substrate in subpixel units, The method for manufacturing a display device according to claim 7, wherein in the pasting step, the individual pieces on the substrate are transferred onto the substrate.

9. The method for manufacturing a display device according to claim 7 or 8, wherein the substrate is a transparent substrate.

10. A method for manufacturing a display device according to any one of claims 7 to 9, wherein the average transmittance of visible light of the substrate to which the plurality of pieces are attached after the attachment step is 20% or more.

11. A method for manufacturing a display device according to any one of claims 7 to 10, wherein the size of the light-emitting element is less than 200 μm.

12. A method for manufacturing a display device according to any one of claims 7 to 11, wherein the ratio of the area of ​​the individual pieces to the area of ​​the light-emitting element is 0.5 to 5.

0.

13. The method for manufacturing a display device according to any one of claims 7 to 12, wherein the curable resin film contains conductive particles, and the conductive particles are arranged in a planar direction.

14. Multiple light-emitting elements, A substrate on which the light-emitting elements are arranged, The system comprises a cured resin film connecting the plurality of light-emitting elements and the substrate, The light-emitting device wherein the cured resin film consists of a plurality of individual pieces, and the substrate is exposed between the individual pieces.

15. A piece formation step involves removing a portion of the curable resin film formed on a substrate and forming a plurality of individual pieces made of the curable resin film on the substrate, The process of attaching the plurality of pieces onto the substrate, The process involves mounting light-emitting elements onto individual pieces attached to the substrate. A method for manufacturing a light-emitting device having [a specific feature].

16. The device comprises a base material and a plurality of individual pieces, each made of a curable resin film formed on the base material. An adhesive film in which the distance between the individual pieces is 3 μm or more and 3000 μm or less.

17. A method for manufacturing an adhesive film, comprising irradiating a laser beam onto a portion of the substrate where a curable resin film has been formed, thereby forming individual pieces made of a curable resin film on the substrate.

Images