Display device and method for fabricating display device

Abstract

To provide a method for fabricating a display device which can suppress positional displacement and breakage of a light-emitting element.SOLUTION: A method for fabricating a display device includes the steps of: forming a light-emitting element in a first substrate; applying an elastic member in a second substrate; and transferring the light-emitting element from the first substrate to the second substrate by using a laser beam, while the first substrate and the second substrate are being separate from each other. The storage elastic modulus of the elastic member is at least 0.01 Pa, the loss elastic modulus of the elastic member is at least 10.0 Pa, and the viscosity of the elastic member is at least 1.8 Pas.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a display device and a method for manufacturing a display device.

Background Art

[0002] In recent years, display devices have been proposed in which the image resolution is improved by mounting light-emitting elements at high density. In a method for manufacturing such a display device, in order to mount light-emitting elements at high density, a step of transferring the light-emitting elements provided on a substrate to another substrate is adopted.

[0003] Patent Document 1 discloses a laser lift-off (LLO) method of transferring a light-emitting element by irradiating the light-emitting element on a substrate with laser light.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the LLO method, the light-emitting element irradiated with laser light flies at high speed. Therefore, the light-emitting element is strongly impacted when being transferred to the substrate, and positional deviation, cracks, chips, and breakage of the light-emitting element may occur.

[0006] An object of the present invention is to provide a method for manufacturing a display device capable of suppressing quality degradation such as cracks and chips and positional deviation of a light-emitting element.

Means for Solving the Problems

[0007] According to one aspect of the present invention, there is provided a method for manufacturing a display device, comprising: a step of forming a light-emitting element on a first substrate; a step of applying an elastic member on a second substrate; and a step of transferring the light-emitting element from the first substrate to the second substrate using laser light while the first substrate and the second substrate are separated from each other, wherein the storage elastic modulus of the elastic member is 0.01 Pa or more, the loss elastic modulus of the elastic member is 10.0 Pa or more, and the viscosity of the elastic member is 1.8 Pa·s or more.

[0008] According to another aspect of the present invention, there is provided a display device comprising: a substrate; an elastic member formed on the substrate; and a light-emitting element formed on the substrate, wherein the storage elastic modulus of the elastic member is 0.01 Pa or more, the loss elastic modulus of the elastic member is 10.0 Pa or more, and the viscosity of the elastic member is 1.8 Pa·s or more.

Advantages of the Invention

[0009] According to the present invention, it is possible to provide a method for manufacturing a display device capable of suppressing displacement and damage of a light-emitting element.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

[0011] Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. Elements having common functions throughout the drawings are denoted by the same reference numerals, and redundant descriptions may be omitted or simplified.

[0012] [First Embodiment] FIG. 1 is a block diagram of a display device according to the present invention. The display device according to the present embodiment can be a television display, a computer display, a smartphone, a tablet computer, a signage, a flexible display, or the like. The display device includes a display panel 1, a controller 2, a data driver 3, and a gate driver 4. In FIG. 1, the horizontal direction of the display panel 1 is defined as the X direction, the vertical direction of the display panel 1 is defined as the Y direction, and the direction perpendicular to the display surface of the display panel 1 is defined as the Z direction.

[0013] The display panel 1 can be an LED (LED: Light-Emitting Diode) panel or the like. The display panel 1 includes a plurality of pixels 10 arranged in an array, and each pixel includes a micro LED. The display panel 1 displays an image based on a signal supplied from the controller 2.

[0014] The controller 2 controls the timing for supplying image data to the display panel 1. The controller 2 receives various timing signals including a main clock signal, a horizontal synchronization signal, a vertical synchronization signal, and a data enable signal from the host system. The timing controller 2 generates a data signal data and a data control signal DCS, and outputs them to the data driver 3. Further, the controller 2 generates a gate control signal GCS and outputs it to the gate driver 4.

[0015] The data driver 3 is connected to the display panel 1 via a plurality of data lines DL. The data driver 3 converts the data signal data from a digital signal to an analog signal based on the data control signal DCS. The data driver 3 supplies the data signal to a plurality of pixels 10 of the display panel 1 via the plurality of data lines DL.

[0016] The gate driver 4 is connected to the display panel 1 via a plurality of gate lines GL. The gate driver 4 generates a gate signal based on the gate control signal GCS. The gate driver 4 sequentially scans the plurality of gate lines GL and supplies the gate signal to a plurality of pixels 10 of the display panel 1.

[0017] Each of the controller 2, the data driver 3, and the gate driver 4 may be constituted by one or more semiconductor integrated circuits. Also, some or all of the controller 2, the data driver 3, and the gate driver 4 may be integrally constituted as one semiconductor integrated circuit.

[0018] FIG. 2 is a cross-sectional view of the display device according to the present embodiment and is a cross-sectional view of the display panel 1 taken along the line I-I' in FIG. 1. For simplicity of explanation, only four LED elements 15 are shown in FIG. 2 and the following description. The display panel 1 includes a substrate 11, an elastic member 12, a pad 13, a connection member 14, an LED element 15, an insulating layer 16, and a glass substrate 17.

[0019] The substrate 11 is made of a material having rigidity such as glass. Also, the substrate 11 may be a stretchable flexible substrate. When the substrate 11 is a flexible substrate, the substrate 11 is made of a plastic such as polyimide or polyester. The substrate 11 has a thin film transistor (TFT: Thin Film Transistor) (not shown). The thin film transistor constitutes the pixel circuit of the pixel 10.

[0020] The elastic member 12 is provided on the substrate 11. In order to suppress the displacement and breakage of the LED element 15, the elastic member 12 preferably has a storage elastic modulus of 0.01 Pa or more and a loss elastic modulus of 10.0 Pa or more before curing, and has a viscosity of 1.8 Pas or more. The thickness of the elastic member 12 is 10 μm or less, preferably 1 μm or more and 5 μm or less, and desirably not more than the height of the LED element 15 described later. The elastic member 12 is composed of a thermosetting resin. The thermosetting resin may include, for example, an acrylic compound, a silicone compound, an epoxy compound, an epoxy acrylate compound, an oxetane compound, an episulfide compound, an acrylic silicone compound, a methacrylic compound, a phenol compound, an amino compound, an unsaturated polyester compound, and a polyurethane compound.

[0021] The acrylic compound may be ethoxylated bisphenol A diacrylate represented by Chemical Formula 1. In Chemical Formula 1, R independently represents a hydrogen atom or an organic group, and m and n independently represent an integer of 0 or more.

Chemical formula

[0022] Further, the acrylic compound may be a divinylbenzylfluorene acrylic compound represented by Chemical Formula 2. In Chemical Formula 2, R 1a , R 1b , R 2a , R 2b , R 3a , R 3b , R 4a , R 4b independently represents a hydrogen atom or an organic group, and k1, k2, m1, m2, n1, n2, p1, and p2 independently represent an integer of 0 or more.

Chemical formula

[0023] Furthermore, the acrylic compound may be tris-(2-acryloxyethyl) isocyanurate represented by Chemical Formula 3. In Chemical Formula 3, X independently represents a hydrogen atom or an organic group, and l, m, and n represent integers of 0 or more.

Chem.

[0024] The silicone compound may be an epoxy-modified organosiloxane represented by Chemical Formula 4. In Chemical Formula 4, R1, R2, and E1 independently represent a hydrogen atom or an organic group, and l, m, and n independently represent integers of 0 or more.

Chem.

[0025] Also, the silicone compound may be an epoxy-modified organosiloxane represented by Chemical Formula 5.

Chem.

[0026] The epoxy compound may be, for example, a phenol novolak type epoxy compound, a cresol novolak type epoxy compound, a bisphenol A type epoxy compound, a bisphenol F type epoxy compound, phenyl glycidyl ether, p-butylphenol glycidyl ether, triglycidyl isocyanurate, diglycidyl isocyanurate, allyl glycidyl ether, or glycidyl methacrylate.

[0027] Also, the epoxy compound may be a divinylbenzylfluorene epoxy compound represented by Chemical Formula 6. In Chemical Formula 6, R 1 , R 2 , R 3 , R 4 independently represent a hydrogen atom or an organic group, and k and m represent integers of 0 or more.

Chem.

[0028] Furthermore, the epoxy compound can be a bisphenol A diglycidyl ether acrylate adduct represented by Chemical Formula 7.

Chemical formula

[0029] The elastic member 12 may be composed of an ultraviolet curable resin instead of the thermosetting resin. The ultraviolet curable resin can be, for example, a (meth)acrylate compound such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, glycerol (meth)acrylate. Note that "(meth)acrylate" means one or both of acrylate and methacrylate, and "(meth)acrylic acid" means one or both of acrylic acid and methacrylic acid.

[0030] The pad 13 is provided on the substrate 11. The pad 13 is embedded in the elastic member 12. The pad 13 can be composed of a metal such as aluminum (Al), gold (Au), copper (Cu), nickel (Ni).

[0031] The connecting member 14 is provided on the pad 13. The connecting member 14 can be made of a solder-based material. The solder-based material can include metals such as tin (Sn), nickel (Ni), copper (Cu), antimony (Sb), aluminum (Al), zinc (Zn), iron (Fe), gold (Au), silver (Ag), titanium (Ti), germanium (Ge), tellurium (Te), cobalt (Co), bismuth (Bi), manganese (Mn), chromium (Cr), molybdenum (Mo), palladium (Pd), indium (In), etc. Note that the connecting member 14 may be made of an organic conductive material or conductive nanoparticles instead of the solder-based material.

[0032] The LED element 15 includes terminals 151, 152, and a semiconductor layer 153, and the LED element 15 is electrically connected to the connecting member 14 via the terminals 151, 152. The LED element 15 is provided on the elastic member 12. The terminals 151 and 152 can be made of metals such as gold, silver, tin, nickel, palladium, etc. The semiconductor layer 153 is connected to the terminals 151 and 152. The semiconductor layer 153 is composed of a p-type semiconductor and an n-type semiconductor and functions as an LED. The height of the LED element 15 is preferably equal to or greater than the thickness of the elastic member 12. The height of the LED element 15 can be 100 μm or less, for example, 1 μm or more and 10 μm or less. The LED element 15 corresponds to a sub-pixel of the pixel 10. For example, the pixel 10 has three LED elements 15, namely, an LED element 15 (red LED) that emits red light, an LED element 15 (green LED) that emits green light, and an LED element 15 (blue LED) that emits blue light.

[0033] The insulating layer 16 is provided on the elastic member 12. The insulating layer 16, together with the elastic member 12, covers the LED element 15. The insulating layer 16 may be made of an inorganic insulating material such as silicon oxide (SiOx) or silicon nitride (SiNx), or may be made of an insulating organic substance or the like.

[0034] The glass substrate 17 is provided on the insulating layer 16. The glass substrate 17 may be made of an inorganic insulating material such as silicon oxide (SiOx) or silicon nitride (SiNx), or may be made of an insulating organic material or the like. The glass substrate 17 has a function of preventing the intrusion of impurities such as moisture or oxygen from the outside.

[0035] FIG. 3 is a schematic diagram showing a method for manufacturing the display panel 1 according to the present embodiment. FIGS. 3(a) to 3(d) show the steps of forming the LED element 15 on the wafer 5. For the sake of simplicity of explanation, FIG. 3 shows one LED element 15 out of a plurality of LED elements 15 formed on the wafer 5.

[0036] First, as shown in FIG. 3(a), a wafer 5 is prepared. The wafer 5 can be, for example, a sapphire substrate composed of a single crystal of aluminum oxide. The wafer 5 can be manufactured by a well-known method such as the CZ (CZ: Czochralski) method or the EFG (EFG: Edge-defined Film-fed Growth) method. Note that the wafer 5 is provided for each color emitted by the LED element 15. For example, when the display panel 1 has three types of LED elements 15, namely red LEDs, green LEDs, and blue LEDs, three wafers 5 for forming the LED elements 15 of each color are prepared.

[0037] Next, as shown in FIG. 3(b), a semiconductor layer 153 composed of three layers, an n-type layer 154, a light-emitting layer 155, and a p-type layer 156, is formed on the wafer 5. The n-type layer 154 can be formed by adding an n-type impurity such as phosphorus (P) or arsenic (As) to gallium nitride (GaN). The light-emitting layer 155 can be formed of indium gallium nitride (InGaN) or the like. The p-type layer 156 can be formed by adding a p-type impurity such as boron (B) or aluminum to gallium nitride. The n-type layer 154, the light-emitting layer 155, and the p-type layer 156 can be formed by a well-known method such as the LPE (LPE: Liquid Phase Epitaxy) method or the MOVPE (MOVPE: Metal Organic Vapor Phase Epitaxy) method.

[0038] Next, as shown in FIG. 3(c), a part of the light-emitting layer 155 and the p-type layer 156 is removed to expose the n-type layer 154. The removal of the light-emitting layer 155 and the p-type layer 156 can be performed by well-known methods such as photolithography, electron beam lithography, and laser patterning.

[0039] Next, as shown in FIG. 3(d), a through-hole penetrating the light-emitting layer 155 and the p-type layer 156 is formed to expose the n-type layer 154. The through-hole can be formed, for example, by etching. Next, the insulating layer 158 is embedded in the through-hole. The insulating layer 158 may be composed of an inorganic insulating material such as silicon oxide (SiOx) or silicon nitride (SiNx), or may be composed of an insulating organic substance or the like. Next, a through-hole penetrating the insulating layer 158 is formed to expose the n-type layer 154. The through-hole can be formed, for example, by etching. Next, the through electrode 157 is formed in the through-hole. The through electrode 157 can be composed of a metal such as gold, silver, tin, nickel, or palladium. Next, the terminal 151 is formed on the p-type layer 156, and the terminal 152 is formed on the through electrode 157. Thus, the LED element 15 including the terminals 151 and 152, the n-type layer 154, the light-emitting layer 155, the p-type layer 156, the through electrode 157, and the insulating layer 158 is formed on the wafer 5. The LED element 15 formed in this way is transferred to the substrate 11 in the manufacturing process of the display panel 1 described later.

[0040] FIG. 4 is a schematic diagram showing a method for manufacturing the display panel 1. FIGS. 4(a) to 4(g) show the steps of forming the elastic member 12, the pad 13, the connection member 14, the LED element 15, the insulating layer 16, and the glass substrate 17 on the substrate 11.

[0041] First, as shown in FIG. 4(a), the substrate 11 is prepared. Next, as shown in FIG. 4(b), the pad 13 and the connection member 14 are sequentially formed on the substrate 11. The pad 13 and the connection member 14 can be formed by well-known methods such as photolithography, electron beam lithography, and laser patterning.

[0042] Next, as shown in FIG. 4(c), the elastic member 12 is applied onto the substrate 11 using the nozzle 6. In FIG. 4(c), the arrow shown above the nozzle 6 represents the traveling direction of the nozzle 6. The thickness of the elastic member 12 is set to a predetermined thickness. The predetermined thickness can be 10 μm or less, preferably 1 μm or more and 5 μm or less. Note that FIG. 4(c) shows an example in which the elastic member 12 is applied while the nozzle 6 moves on the substrate 11, but the present invention is not limited thereto. For example, the elastic member 12 may be applied while moving the substrate 11 with respect to the fixed nozzle 6.

[0043] Next, as shown in FIG. 4(d), the wafer 5 is opposed to the substrate 11 at a predetermined interval. The wafer 5 and the substrate 11 are positioned by a stage (not shown) that can move up and down. The gap distance between the wafer 5 and the substrate 11 can be set to a predetermined distance by moving the stage (not shown) up and down.

[0044] Next, as shown in FIG. 4(e), by the LLO method, the laser light L is irradiated from a laser light source (not shown) to the LED element 15 from the back surface of the wafer 5, and the LED element 15 is transferred onto the substrate 11. The laser light source can be an excimer laser, a solid laser, or the like. The laser light L is absorbed by the gallium nitride that constitutes the n-type layer 154 of the LED element 15, and the gallium nitride is decomposed into gallium and nitrogen. By decomposing the portion of the n-type layer 154 that contacts the wafer 5, the LED element 15 is peeled off from the wafer 5. The peeled-off LED element 15 flies toward the elastic member 12. The LED element 15 is caught in the elastic member 12, and the terminals 151 and 152 of the LED element 15 are electrically connected to the pads 13 via the connection member 14. As described above, the LED element 15 can be transferred from wafers 5 that are different for each color of the LED element 15.

[0045] Next, as shown in FIG. 4(f), after the transfer of all the LED elements 15 is completed, the wafer 5 is separated from above the substrate 11. In this way, the LED elements 15 are formed on the substrate 11.

[0046] Next, as shown in FIG. 4(g), the elastic member 12 is cured by heat or the like, and an insulating layer 16 and a glass substrate 17 are sequentially formed on the elastic member 12. The heating of the elastic member 12 can be performed by any heat source such as a hot plate, an infrared lamp, or an infrared laser. Thus, the display panel 1 is manufactured.

[0047] Note that the melting point of the connection member 14 may be equal to or lower than the heating temperature when the elastic member 12 is heat-cured. In this case, the connection member 14 melts during the heat-curing of the elastic member 12 and can reinforce the electrical connection between the pad 13 and the terminals 151 and 152 of the LED element 15.

[0048] In the present embodiment, by setting the elastic modulus and viscosity of the elastic member 12 to predetermined values, displacement and breakage of the LED element 15 are suppressed. FIG. 5 is a schematic diagram for explaining the displacement of the LED element 15 according to the present embodiment. The LED element 15 receives kinetic energy E1 due to irradiation with laser light and flies toward the elastic member 12. For example, when the LED element 15 has a size of 20×30 μm and a thickness of 10 μm, the LED element 15 can fly at a speed of 80 m / s (288 km / h). When the LED element 15 collides with the elastic member 12, the LED element 15 receives kinetic energy E2 in the direction opposite to the kinetic energy E1 as a repulsive force from the elastic member 12. Here, when the elastic modulus and viscosity of the elastic member 12 are not appropriate, the elastic member 12 cannot sufficiently absorb the kinetic energy E1 of the LED element 15. As a result, the LED element 15 receives a large kinetic energy E2, and displacement of the LED element 15 and breakage such as chipping of the LED element 15 may occur.

[0049] In this embodiment, by setting the elastic modulus and viscosity of the elastic member 12 to predetermined values, the elastic member 12 can effectively absorb the kinetic energy E1 of the LED element 15 and reduce the kinetic energy E2 as the repulsive force. As a result, it becomes possible to effectively suppress the displacement and breakage of the LED element 15. Further, when the elastic member 12 is heat-cured, the LED element 15 is covered by the elastic member 12 having elasticity. Thereby, the elastic member 12 can have a function of protecting the LED element 15 from external forces.

[0050] Note that the LED element 15 may be transferred at a pitch different from the pitch of the LED element 15 on the wafer 5. For example, the LED element 15 may be transferred at the pitch of the LED element 15 in the display panel 1 after manufacturing. Thereby, a process for converting the pitch of the LED element 15 becomes unnecessary, and the manufacturing time can be shortened.

[0051] [Second Embodiment] Subsequently, a method for manufacturing a display device according to the second embodiment will be described. The method for manufacturing a display device according to this embodiment is different from the first embodiment in that a filler 18 is filled in the elastic member 12 instead of the connection member 14. Hereinafter, the description will focus on the configuration different from the first embodiment.

[0052] FIG. 6 is a cross-sectional view of a display device according to the second embodiment, corresponding to the cross-sectional view taken along line I-I' in FIG. 1. The display panel 1 has a filler 18 instead of the connection member 14. The filler 18 is filled in the elastic member 12. The filler 18 electrically connects the pad 13 and the terminals 151 and 152. The filler 18 can be made of a solder-based material. The solder-based material may contain metals such as tin, nickel, copper, antimony, aluminum, zinc, iron, gold, silver, titanium, germanium, tellurium, cobalt, bismuth, manganese, chromium, molybdenum, palladium, and indium.

[0053] The particle size of the filler 18 is preferably equal to or less than the distance between the terminal 151 and the terminal 152. For example, it is preferably 10 μm or less. If the particle size of the filler 18 is greater than 10 μm, the filler 18 may be electrically connected to both the terminal 151 and the terminal 152, resulting in a short circuit.

[0054] FIG. 7 is a schematic diagram showing a method of manufacturing the display panel 1 according to the present embodiment. FIGS. 7(a) to 7(h) show the steps of forming the elastic member 12, the pad 13, the LED element 15, the insulating layer 16, the glass substrate 17, and the filler 18 on the substrate 11.

[0055] First, as shown in FIG. 7(a), the substrate 11 is prepared. Next, as shown in FIG. 7(b), the pad 13 is formed on the substrate 11. Next, as shown in FIG. 7(c), the elastic member 12 is applied onto the substrate 11 using the nozzle 6. Next, as shown in FIG. 7(d), the elastic member 12 is filled with the filler 18. The filling of the filler 18 may be performed using a laser beam or a nozzle. Alternatively, an elastic member 12 pre-filled with the filler 18 may be applied. In this case, filling of the filler 18 after application of the elastic member 12 is unnecessary.

[0056] Next, as shown in FIG. 7(e), the wafer 5 is opposed to the substrate 11 at a predetermined interval. Next, as shown in FIG. 7(f), the LED element 15 is transferred onto the substrate 11 by the LLO method. Next, as shown in FIG. 7(g), after the transfer of all the LED elements 15 is completed, the wafer 5 is separated from above the substrate 11. Next, as shown in FIG. 7(h), after the elastic member 12 is heat-cured, the insulating layer 16 and the glass substrate 17 are sequentially formed on the elastic member 12. In this way, the display panel 1 is manufactured.

[0057] Also in this embodiment, the elastic member 12 can effectively absorb the kinetic energy of the LED element 15. Therefore, displacement and breakage of the LED element 15 can be suppressed. Further, in this embodiment, instead of forming the connection member 14 on the pad 13, the elastic member 12 is filled with the filler 18. Therefore, when the process of forming the connection member 14 on the pad 13 is complicated, the configuration in this embodiment can be effective.

[0058] [Third Embodiment] Subsequently, a method for manufacturing a display device according to the third embodiment will be described. The method for manufacturing a display device in this embodiment is different from the first embodiment in that a pitch conversion substrate is prepared. Hereinafter, the description will focus on the configuration different from the first embodiment.

[0059] FIG. 8 is a schematic diagram showing a method for manufacturing the display panel 1 according to this embodiment. FIGS. 8(a) to 8(e) show the process of transferring the LED element 15 from the pitch conversion substrate 8.

[0060] First, as shown in FIG. 8(a), the laser beam L is irradiated from the back surface of the wafer 5 onto the LED element 15 to transfer the LED element 15 to the temporary substrate 7. The temporary substrate 7 is made of a material having rigidity such as glass. An adhesive member 71 is provided on the upper surface of the temporary substrate 7. The adhesive member 71 can be a pressure-bonding resin material, an adhesive, an adhesive tape, or the like. The positioning of the wafer 5 and the temporary substrate 7 is performed by a stage (not shown) that can be raised and lowered. The distance between the LED element 15 and the adhesive member 71 can be set to a predetermined distance by raising and lowering the stage (not shown).

[0061] Next, as shown in FIG. 8(b), the laser light L is irradiated onto the LED element 15 from the back surface of the temporary substrate 7, and the LED element 15 is transferred onto the pitch conversion substrate 8. The pitch conversion substrate 8 is made of a material having rigidity such as glass. An adhesive member 81 is provided on the upper surface of the pitch conversion substrate 8. The adhesive member 81 can be a pressure-bonding resin material, an adhesive, an adhesive tape, or the like. The laser light L irradiates the LED element 15 at a pitch different from the pitch of the LED element 15 on the temporary substrate 7. Thereby, the pitch of the LED element 15 transferred onto the pitch conversion substrate 8 can be changed from the pitch of the LED element 15 on the temporary substrate 7.

[0062] Next, as shown in FIG. 8(c), after the transfer of the LED element 15 is completed, the temporary substrate 7 is separated from above the pitch conversion substrate 8. In this way, the LED element 15 is formed on the pitch conversion substrate 8.

[0063] Next, as shown in FIG. 8(d), the pitch conversion substrate 8 is opposed to the substrate 11 at a predetermined interval. In FIG. 8(d), an elastic member 12, a pad 13, and a connection member 14 are formed on the substrate 11. Next, as shown in FIG. 8(e), the LED element 15 is transferred onto the substrate 11 by the LLO method.

[0064] Also in this embodiment, the elastic member 12 can effectively absorb the kinetic energy of the LED element 15. Therefore, displacement and breakage of the LED element 15 can be suppressed. Further, in this embodiment, a pitch conversion substrate 8 is prepared. Therefore, when the process of directly transferring the LED element 15 from the wafer 5 to the substrate 11 and arranging the LED elements 15 at a desired pitch is complicated, the configuration in this embodiment can be effective.

[0065] [Fourth Embodiment] Subsequently, a method for manufacturing a display device according to the fourth embodiment will be described. The method for manufacturing a display device in this embodiment is different from the first embodiment in that it has a repair process for the LED element 15. Hereinafter, the description will focus on the configuration different from the first embodiment.

[0066] FIG. 9 is a schematic diagram showing a method for manufacturing the display panel 1 according to the fourth embodiment. FIGS. 9(a) to 9(g) show the repair process of the LED element 15. The repair process can be performed after transferring the LED element 15 to the substrate 11 and before forming the insulating layer 16 on the elastic member 12.

[0067] First, as shown in FIG. 9(a), the misaligned and transferred LED element 15 is irradiated with the laser light L. As shown in FIG. 9(b), the LED element 15, the connection member 14, and the elastic member 12 are removed by the irradiation of the laser light L.

[0068] As shown in FIG. 9(c), a new connection member 14 is formed on the pad 13. The new connection member 14 may be formed by a nozzle, or may be formed by flying the connection member 14 from another substrate onto the pad 13 by LLO.

[0069] Next, as shown in FIG. 9(d), the elastic member 12 is filled with the filler 18 using the nozzle 6. As shown in FIG. 9(e), the thickness of the elastic member 12 filled here is preferably equal to the thickness of the surrounding elastic member 12. Next, as shown in FIG. 9(f), the LED element 15 is transferred from the wafer 5 to the substrate 11 by the LLO method. Next, as shown in FIG. 9(g), the elastic member 12 is cured by heat or the like, and the LED element 15 that is the target of repair can be removed and the LED element 15 can be newly transferred to the desired position.

[0070] Also in this embodiment, the elastic member 12 can effectively absorb the kinetic energy of the LED element 15. Therefore, it is possible to suppress the displacement and breakage of the LED element 15 during the transfer of the LED element 15 in the repair process. Thereby, the time required for the repair process of the LED element 15 can be shortened.

[0071] Note that the repair process according to this embodiment may be applied to the manufacturing process of a conventional display panel. A conventional display panel has, for example, an LED element 15 formed of an anisotropic conductive film (ACF: Anisotropic Conductive Film) instead of the elastic member 12. When the repair process according to this embodiment is applied to such a display panel, the repaired display panel has the LED element 15 provided in the ACF and the LED element 15 provided in the elastic member 12.

[0072] Hereinafter, the results of experiments on the elastic member according to the embodiment of the present invention will be described.

[0073]

Table 1

[0074] Table 1 shows the content (g) of material A, the content (g) of material B, the storage elastic modulus (Pa), the loss elastic modulus (Pa), the viscosity (Pa·s) of the uncured elastic member, and the evaluation of the displacement and breakage of the LED element in Examples 1 to 5 and Comparative Example 1. In the examples and the comparative example, the thickness of the elastic member is 5 μm. The storage elastic modulus and the loss elastic modulus were measured by dynamic viscoelastic measurement. Also, the viscosity was measured in accordance with JIS Z8803:2011 using a vibrating viscometer or a tuning fork vibrating viscometer.

[0075] The "evaluation" in Table 1 indicates whether the displacement and breakage of the LED element are suppressed when a display device is manufactured using the elastic members according to the examples and the comparative example. When the displacement and breakage of the LED element are sufficiently suppressed, the evaluation is determined to be good (OK), and when the displacement and breakage of the LED element are not sufficiently suppressed, the evaluation is determined to be bad (NG).

[0076] In Example 1, the content of Material A was 4.0548 g, and the content of Material B was 10.0091 g. The storage elastic modulus of the elastic member was 0.01538 Pa. The loss elastic modulus of the elastic member was 12.91 Pa. The viscosity of the elastic member was 2.054 Pas. The ratio of LED elements with displacement and breakage met the standard, and the evaluation was good (OK).

[0077] In Example 2, the content of Material A was 5.4943 g, and the content of Material B was 10.0031 g. The storage elastic modulus of the elastic member was 0.0322 Pa. The loss elastic modulus of the elastic member was 18.98 Pa. The viscosity of the elastic member was 3.02 Pas. The ratio of LED elements with displacement and breakage met the standard, and the evaluation was good (OK).

[0078] In Example 3, the content of Material A was 6.9336 g, and the content of Material B was 10.0073 g. The storage elastic modulus of the elastic member was 0.04773 Pa. The loss elastic modulus of the elastic member was 19.21 Pa. The viscosity of the elastic member was 3.057 Pas. The ratio of LED elements with displacement and breakage met the standard, and the evaluation was good (OK).

[0079] In Example 4, the content of Material A was 8.3749 g, and the content of Material B was 10.0048 g. The storage elastic modulus of the elastic member was 0.09388 Pa. The loss elastic modulus of the elastic member was 29.62 Pa. The viscosity of the elastic member was 4.714 Pas. The ratio of LED elements with displacement and breakage met the standard, and the evaluation was good (OK).

[0080] In Example 5, the content of Material A was 9.8113 g, and the content of Material B was 10.0033 g. The storage elastic modulus of the elastic member was 0.1298 Pa. The loss elastic modulus of the elastic member was 29.62 Pa. The viscosity of the elastic member was 4.714 Pas. The ratio of LED elements with displacement and breakage met the standard, and the evaluation was good (OK).

[0081] In Comparative Example 1, the content of Material A was 2.6115 g, and the content of Material B was 10.0061 g. The storage elastic modulus of the elastic member was 0.00298 Pa. The loss elastic modulus of the elastic member was 9.745 Pa. The viscosity of the elastic member was 1.551 Pas. The ratio of the LED elements that had displacement and breakage did not meet the standard, and the evaluation was poor (NG).

[0082] As described above, according to the present embodiment, it is possible to provide a method for manufacturing a display device capable of suppressing displacement and breakage of a light-emitting element.

[0083] Further, the elastic member 12 preferably has a storage elastic modulus of 0.01 Pa or more and a loss elastic modulus of 10.0 Pa or more, and has a viscosity of 1.8 Pas or more. Thereby, the elastic member 12 can effectively absorb the kinetic energy of the LED element 15.

[0084] Further, the thickness of the elastic member 12 is preferably equal to or less than the height of the LED element 15, and the thickness of the elastic member 12 is preferably 10 μm or less, more preferably 5 μm or less. Thereby, the elastic member 12 can more effectively absorb the kinetic energy of the LED element 15.

[0085] Further, the elastic member 12 preferably has a storage elastic modulus of 100 Pa or less and a loss elastic modulus of 1000 Pa or less. Thereby, the elastic member 12 can more effectively absorb the kinetic energy of the LED element 15.

[0086] The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, an example in which a part of the configuration of one embodiment is added to another embodiment, or an example in which a part of the configuration of another embodiment is replaced, is also an embodiment of the present invention. In addition, regarding parts that are not particularly described or illustrated in the embodiment, well-known techniques and publicly known techniques in the relevant technical field can be appropriately applied.

Explanation of Reference Numerals

[0087] 1 Display panel 2 Controller 3 Data driver 4 Gate driver 10 Pixel 11 Substrate 12 Elastic member 13 Pad 14 Connection member 15 LED element 16 Insulating layer 17 Glass substrate

Claims

1. A step of forming a light-emitting element on a first substrate; A step of applying an elastic member to a second substrate; A step of transferring the light-emitting element from the first substrate to the second substrate using laser light while the first substrate and the second substrate are separated from each other; and The storage elastic modulus of the elastic member is 0.01 Pa or more; The loss elastic modulus of the elastic member is 10.0 Pa or more; A method for manufacturing a display device, characterized in that the viscosity of the elastic member is 1.8 Pas or more.

2. The method for manufacturing a display device according to claim 1, characterized in that the thickness of the elastic member is equal to or less than the height of the light-emitting element.

3. The method for manufacturing a display device according to claim 1, characterized in that the storage elastic modulus of the elastic member is 100 Pa or less.

4. The method for manufacturing a display device according to claim 1, characterized in that the loss elastic modulus of the elastic member is 1000 Pa or less.

5. The method for manufacturing a display device according to claim 1, characterized in that the viscosity of the elastic member is 5.612 Pas or less.

6. The method for manufacturing a display device according to claim 1, characterized in that the elastic member is formed of a thermosetting resin.

7. The method for manufacturing a display device according to claim 6, characterized in that the thermosetting resin is at least one of an acrylic compound, a silicone compound, an epoxy compound, an epoxy acrylate compound, an oxetane compound, an episulfide compound, an acrylic silicone compound, a methacrylic compound, a phenol compound, an amino compound, an unsaturated polyester compound, and a polyurethane compound.

8. The acrylic compound is a compound represented by Chemical Formula 1; In Chemical Formula 1, R independently represents a hydrogen atom or an organic group, and m and n independently represent integers of 0 or more. The method for manufacturing a display device according to claim 7. 【Chemical 1】

9. The acrylic compound is a compound represented by Chemical Formula 2; In the chemical formula 2, R １ａ , R １ｂ , R ２ａ , R ２ｂ , R ３ａ , R ３ｂ , R ４ａ , R ４ｂ independently represents a hydrogen atom or an organic group, and k1, k2, m1, m2, n1, n2, p1, and p2 independently represent integers of 0 or more. The method for manufacturing a display device according to claim 7, characterized in that. [Chemical Formula 2]

10. The acrylic compound is a compound represented by Chemical Formula 3; In Chemical Formula 3, X independently represents a hydrogen atom or an organic group, and l, m, and n represent integers of 0 or more. The method for manufacturing a display device according to claim 7. 【Chemical Formula 3】

11. The silicone compound is a compound represented by Chemical Formula 4; In the chemical formula 4, R １ , R ２ , E １ each independently represents a hydrogen atom or an organic group, and l, m, and n each independently represent an integer of 0 or more. The method for manufacturing a display device according to claim 7, characterized in that. 【Chemical Formula 4】

12. The method for manufacturing a display device according to claim 7, characterized in that the silicone compound is a compound represented by Chemical Formula 5. 【Chemical Formula 5】

13. The epoxy compound is a compound represented by Chemical Formula 6, In the chemical formula 6, R １ , R ２ , R ３ , R ４ each independently represents a hydrogen atom or an organic group, and k and m represent integers of 0 or more. A method for manufacturing a display device according to claim 7, characterized in that. 【Chemical Formula 6】

14. The manufacturing method of the display device according to claim 7, wherein the epoxy compound is a compound represented by Chemical Formula 7. 【Chemical Formula 7】

15. The manufacturing method of the display device according to claim 1, wherein the elastic member is formed of an ultraviolet curable resin.

16. The manufacturing method of the display device according to claim 1, wherein the first substrate is a sapphire substrate.

17. In the transferring step, the pitch of the light-emitting elements formed on the first substrate is different from the pitch of the light-emitting elements transferred to the second substrate. The manufacturing method of the display device according to claim 1.

18. Before the coating step, the manufacturing method of the display device according to claim 1, further comprising a step of forming a connection member for electrically connecting the light-emitting element and the second substrate on the second substrate.

19. The manufacturing method of the display device according to claim 1, further comprising a step of filling a filler for electrically connecting the light-emitting element and the second substrate into the elastic member.

20. The manufacturing method of the display device according to claim 1, wherein the light-emitting element formed on the temporary substrate is transferred to the first substrate, thereby forming the light-emitting element on the first substrate.

21. After the transferring step, a step of removing the light-emitting element and the elastic member on the second substrate; a step of applying the elastic member to the second substrate; The manufacturing method of the display device according to claim 1, further comprising a step of transferring the other light-emitting element from the third substrate to the second substrate using laser light in a state where the third substrate on which the other light-emitting element is formed and the second substrate are separated.

22. The manufacturing method of the display device according to any one of claims 1 to 21, wherein the light-emitting element is a micro LED.

23. A substrate, an elastic member formed on the substrate, and a light-emitting element formed on the substrate, wherein a storage elastic modulus of the elastic member is 0.01 Pa or more, a loss elastic modulus of the elastic member is 10.0 Pa or more, and a viscosity of the elastic member is 1.8 Pas or more. A display device.

24. The display device according to claim 23, wherein a thickness of the elastic member is equal to or less than a height of the light-emitting element.

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