Display device and method for manufacturing the same

Abstract

To provide a display device and a method for manufacturing the display device which can secure the connection stability of a light emitting element and an array board.SOLUTION: A display device comprises: an array board; a plurality of mounting electrodes provided on the array board; a columnar conductor for connection that is provided on each of the plurality of mounting electrodes; a plurality of light emitting elements provided on the array board; a first electrode provided on surfaces of the plurality of light emitting elements that face the array board, and connected to one of the anode and cathode of the light emitting element; a second electrode connected to the other of the anode and cathode of the light emitting element; and a connecting member for covering each of the first and second electrodes. The columnar conductor is made from a material which is harder than the connecting member, and the end of the columnar conductor on the light emitting element side is electrically connected to the connecting member.SELECTED DRAWING: Figure 6

Description

[Technical field]

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

[0002] Display devices using minute light-emitting diodes (micro LEDs) as display elements have been attracting attention (see, for example, Patent Documents 1 to 3). In Patent Documents 1 to 3, conductive connection posts formed on the light-emitting diodes are connected to electrodes on the array substrate, and the light-emitting diodes are mounted on the array substrate. As another connection method, Patent Document 4 describes a technique in which the light-emitting diodes are connected to the array substrate via an anisotropic conductive film containing conductive particles. As a mounting method for such light-emitting diodes, a method is known in which a light-emitting diode formed on a sapphire substrate or the like is picked up by a carrier substrate and then transferred from the carrier substrate to the array substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2018 / 0090394 [Patent Document 2] US Patent Application Publication No. 2018 / 0226287 [Patent Document 3] US Patent Application Publication No. 2017 / 0213803 [Patent Document 4] Patent Publication No. 2021-4988 Summary of the Invention [Problem to be solved by the invention]

[0004] In such a display device, if a conductive connection post is formed on the light-emitting diode, the transfer process of the light-emitting diode to the array substrate may become complicated. On the other hand, if an anisotropic conductive film is used, it may be difficult to ensure connection stability if the anode electrode and cathode electrode of the light-emitting diode are formed at different height positions.

[0005] An object of the present invention is to provide a display device capable of ensuring stable connection between a light emitting element and an array substrate, and a method for manufacturing the display device. [Means for solving the problem]

[0006] A display device according to one embodiment of the present invention comprises an array substrate, a plurality of mounting electrodes provided on the array substrate, a columnar conductor for connection provided on each of the plurality of mounting electrodes, a plurality of light-emitting elements provided on the array substrate, a first electrode provided on a surface of the plurality of light-emitting elements facing the array substrate, the first electrode being connected to one of the anode and cathode of the light-emitting elements, a second electrode being connected to the other of the anode and cathode of the light-emitting elements, and a connecting member covering each of the first electrode and the second electrode, wherein the columnar conductor is made of a material harder than the connecting member, and an end of the columnar conductor on the light-emitting element side is electrically connected to the connecting member.

[0007] A manufacturing method of a display device according to one embodiment of the present invention includes the steps of forming a first electrode and a second electrode of opposite polarity on one surface of the light-emitting element, and forming a connecting member covering each of the first electrode and the second electrode, forming a plurality of mounting electrodes on an array substrate, and forming a columnar conductor for connection to each of the plurality of mounting electrodes, and applying pressure to the light-emitting element to electrically connect the columnar conductor and the connecting member.

[0008] A display device according to one embodiment of the present invention includes an array substrate, a plurality of mounting electrodes provided on the array substrate, a plurality of light-emitting elements provided on the array substrate, a first electrode provided on a surface of the plurality of light-emitting elements facing the array substrate, the first electrode being connected to one of the anode and cathode of the light-emitting element, a second electrode being connected to the other of the anode and cathode of the light-emitting element, and a connecting member covering each of the first electrode and the second electrode, and further includes conductive particles for connection provided on each of the plurality of mounting electrodes, and a sealing material formed of an insulating material and provided around the conductive particles between the array substrate and the plurality of light-emitting elements, the conductive particles being made of a material harder than the connecting member, and the particle size of the first conductive particles overlapping the first electrode being smaller than the particle size of the second conductive particles overlapping the second electrode. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a plan view illustrating a display device according to a first embodiment. [Diagram 2] FIG. 2 is a plan view showing a plurality of pixels. [Diagram 3] FIG. 3 is a circuit diagram showing a pixel circuit. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV' of FIG. [Diagram 5] FIG. 5 is a plan view illustrating a schematic view of the light-emitting element. [Figure 6] FIG. 6 is a cross-sectional view showing a schematic connection configuration between the light-emitting element and the array substrate. [Figure 7] FIG. 7 is a cross-sectional view illustrating a schematic connection configuration between a light-emitting element and an array substrate according to a first modified example of the first embodiment. [Figure 8] FIG. 8 is a plan view diagrammatically illustrating a light emitting element according to a second modified example of the first embodiment. [Figure 9] FIG. 9 is a flowchart illustrating the method for manufacturing the display device according to the first embodiment. [Figure 10] FIG. 10 is a cross-sectional view that typically illustrates the light-emitting element at step ST14 in FIG. [Figure 11]FIG. 11 is a cross-sectional view that typically shows the array substrate at step ST17 in FIG. [Figure 12] FIG. 12 is a cross-sectional view showing a schematic connection configuration between a light-emitting element and an array substrate according to the second embodiment. [Figure 13] FIG. 13 is a cross-sectional view illustrating a connection configuration between a light-emitting element and an array substrate according to a third modified example of the second embodiment. [Figure 14] FIG. 14 is an explanatory diagram for explaining a step of forming an anisotropic conductive film in the manufacturing method of the display device according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The form (embodiment) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiment. In addition, the components described below include those that a person skilled in the art can easily imagine and those that are substantially the same. Furthermore, the components described below can be appropriately combined. Note that the disclosure is merely an example, and those that a person skilled in the art can easily imagine appropriate modifications while maintaining the gist of the invention are naturally included in the scope of the present invention. In addition, in order to make the explanation clearer, the drawings may be schematic in terms of the width, thickness, shape, etc. of each part compared to the actual embodiment, but they are merely examples and do not limit the interpretation of the present invention. In addition, in this specification and each figure, elements similar to those described above with respect to the previous figures may be given the same reference numerals, and detailed explanations may be omitted as appropriate.

[0011] In this specification and the claims, when expressing an aspect of arranging another structure on top of a certain structure, the term "on top" is used, unless otherwise specified, to include both a case in which another structure is arranged directly on top of a certain structure so as to be in contact with the certain structure, and a case in which another structure is arranged above a certain structure via yet another structure.

[0012] (First embodiment) Fig. 1 is a plan view showing a display device according to a first embodiment. As shown in Fig. 1, the display device 1 includes an array substrate 2, pixels Pix, a driving circuit 12, a driving IC (Integrated Circuit) 210, and a cathode wiring 60. The array substrate 2 is a driving circuit substrate for driving each pixel Pix, and is also called a backplane or an active matrix substrate. The array substrate 2 includes a substrate 21, a plurality of transistors, a plurality of capacitors, various wirings, and the like.

[0013] As shown in Fig. 1, the display device 1 has a display area AA and a peripheral area GA. The display area AA is an area that is arranged to overlap with a plurality of pixels Pix and displays an image. The peripheral area GA is an area that does not overlap with the plurality of pixels Pix and is arranged outside the display area AA.

[0014] A plurality of pixels Pix are arranged in a first direction Dx and a second direction Dy in the display area AA of the substrate 21. The first direction Dx and the second direction Dy are parallel to the surface of the substrate 21. The first direction Dx is perpendicular to the second direction Dy. However, the first direction Dx may intersect with the second direction Dy without being perpendicular thereto. The third direction Dz is perpendicular to the first direction Dx and the second direction Dy. The third direction Dz corresponds to, for example, the normal direction of the substrate 21. In the following, a planar view refers to a positional relationship when viewed from the third direction Dz.

[0015] The drive circuit 12 is a circuit that drives multiple gate lines (e.g., a reset control signal line L5, an output control signal line L6, a pixel control signal line L7, and an initialization control signal line L8 (see FIG. 3)) based on various control signals supplied via wiring drawn out from the drive IC 210. The drive circuit 12 selects multiple gate lines sequentially or simultaneously, and supplies gate drive signals to the selected gate lines. In this way, the drive circuit 12 selects multiple pixels Pix connected to the gate lines.

[0016] The driving IC 210 is a circuit that controls the display of the display device 1. A plurality of wirings are drawn from the driving IC 210 toward a plurality of pixels Pix (for example, a video signal line L2, a reset power line L3, and an initialization power line L4 (see FIG. 3)). The driving IC 210 is mounted as a COG (chip on glass) in the peripheral area GA of the substrate 21. However, the driving IC 210 may be mounted on a flexible printed circuit board or a rigid substrate connected to the peripheral area GA of the substrate 21.

[0017] The cathode wiring 60 is provided in the peripheral area GA of the substrate 21. The cathode wiring 60 is provided to surround the pixels Pix in the display area AA and the drive circuit 12 in the peripheral area GA. The cathodes of the light-emitting elements 3 are connected to a common cathode wiring 60, and a fixed potential (e.g., ground potential) is supplied to the cathode wiring 60. More specifically, the cathode electrode 33 (see FIG. 4) of the light-emitting element 3 is connected to the cathode wiring 60 via a columnar conductor 25 and a mounting electrode 24 (see FIG. 4) formed on the array substrate 2.

[0018] FIG. 2 is a plan view showing a plurality of pixels. As shown in FIG. 2, one pixel Pix includes a plurality of sub-pixels 49. For example, the pixel Pix has a sub-pixel 49R, a sub-pixel 49G, and a sub-pixel 49B. The sub-pixel 49R displays a primary color red as a first color. The sub-pixel 49G displays a primary color green as a second color. The sub-pixel 49B displays a primary color blue as a third color. As shown in FIG. 2, in one pixel Pix, the sub-pixels 49R and 49G are arranged in a first direction Dx. The sub-pixels 49G and 49B are arranged in a second direction Dy. Note that the first color, the second color, and the third color are not limited to red, green, and blue, respectively, and any color such as a complementary color can be selected. In the following, when it is not necessary to distinguish between the sub-pixels 49R, 49G, and 49B, they are simply referred to as the sub-pixels 49.

[0019] Each of the sub-pixels 49 has a light-emitting element 3 and a mounting electrode 24. In FIG. 2, one mounting electrode 24 is shown for one light-emitting element 3 to make the drawing easier to see, but in reality, a plurality of mounting electrodes 24 are provided for one light-emitting element 3 corresponding to the anode electrode 32 and the cathode electrode 33 (see FIG. 4). The display device 1 displays an image by emitting different light for each of the light-emitting elements 3R, 3G, and 3B in the sub-pixels 49R, 49G, and 49B. The light-emitting element 3 is an inorganic light-emitting diode (LED: Light Emitting Diode) chip having a size of about 3 μm or more and 300 μm or less in a plan view, and is called a micro LED. The display device 1 having a micro LED in each pixel is also called a micro LED display device. The "micro" in micro LED does not limit the size of the light-emitting element 3.

[0020] The light-emitting elements 3 may emit four or more different colors of light. The arrangement of the sub-pixels 49 is not limited to the configuration shown in Fig. 2. For example, the sub-pixel 49R may be adjacent to the sub-pixel 49B in the second direction Dy. The sub-pixels 49R, 49G, and 49B may be repeatedly arranged in this order in the first direction Dx.

[0021] Fig. 3 is a circuit diagram showing a pixel circuit. Fig. 3 shows a pixel circuit PICA provided in one sub-pixel 49, and the pixel circuit PICA is provided in each of the sub-pixels 49. As shown in Fig. 3, the pixel circuit PICA includes a light-emitting element 3, five transistors, and two capacitances. Specifically, the pixel circuit PICA includes a drive transistor DRT, an output transistor BCT, an initialization transistor IST, a pixel selection transistor SST, and a reset transistor RST. The drive transistor DRT, the output transistor BCT, the initialization transistor IST, the pixel selection transistor SST, and the reset transistor RST are each composed of an n-type TFT (Thin Film Transistor). The pixel circuit PICA also includes a first capacitance Cs1 and a second capacitance Cs2.

[0022] The cathode (cathode electrode 33) of the light-emitting element 3 is connected to the cathode power line L10. The anode (anode electrode 32) of the light-emitting element 3 is connected to the anode power line L1 via the anode wiring 23, the drive transistor DRT, and the output transistor BCT. The anode power line L1 is supplied with an anode power potential PVDD. The cathode power line L10 is supplied with a cathode power potential PVSS via the cathode wiring 60 and the cathode electrode 33. The anode power potential PVDD is a higher potential than the cathode power potential PVSS.

[0023] The anode power line L1 supplies the sub-pixel 49 with an anode power potential PVDD, which is a drive potential. Specifically, the light-emitting element 3 ideally emits light when a forward current (drive current) is supplied thereto by the potential difference (PVDD-PVSS) between the anode power potential PVDD and the cathode power potential PVSS. In other words, the anode power potential PVDD has a potential difference with respect to the cathode power potential PVSS that causes the light-emitting element 3 to emit light. The anode electrode 32 of the light-emitting element 3 is electrically connected to the anode wiring 23, and a second capacitance Cs2 is formed between the anode wiring 23 and the anode power line L1.

[0024] A source electrode of the driving transistor DRT is connected to the anode electrode 32 of the light-emitting element 3 via the anode wiring 23, and a drain electrode of the driving transistor DRT is connected to the source electrode of the output transistor BCT. A gate electrode of the driving transistor DRT is connected to the first capacitance Cs1, the drain electrode of the pixel selection transistor SST, and the drain electrode of the initialization transistor IST.

[0025] The gate electrode of the output transistor BCT is connected to an output control signal line L6, to which an output control signal BG is supplied, and the drain electrode of the output transistor BCT is connected to an anode power supply line L1.

[0026] A source electrode of the initialization transistor IST is connected to an initialization power line L4. An initialization potential Vini is supplied to the initialization power line L4. A gate electrode of the initialization transistor IST is connected to an initialization control signal line L8. An initialization control signal IG is supplied to the initialization control signal line L8. That is, when the initialization transistor IST is turned on, the initialization power line L4 is connected to the gate electrode of the drive transistor DRT via the initialization transistor IST.

[0027] A source electrode of the pixel selection transistor SST is connected to a video signal line L2. A video signal Vsig is supplied to the video signal line L2. A gate electrode of the pixel selection transistor SST is connected to a pixel control signal line L7. A pixel control signal SG is supplied to the pixel control signal line L7.

[0028] A source electrode of the reset transistor RST is connected to a reset power line L3. A reset power potential Vrst is supplied to the reset power line L3. A gate electrode of the reset transistor RST is connected to a reset control signal line L5. A reset control signal RG is supplied to the reset control signal line L5. A drain electrode of the reset transistor RST is connected to the anode wiring 23 (anode electrode 32 of the light-emitting element 3) and the source electrode of the drive transistor DRT. The reset operation of the reset transistor RST resets the voltages held in the first capacitance Cs1 and the second capacitance Cs2.

[0029] A first capacitance Cs1 is formed between the drain electrode of the reset transistor RST and the gate electrode of the drive transistor DRT. The pixel circuit PICA can suppress fluctuations in the gate voltage due to the parasitic capacitance and leakage current of the drive transistor DRT by the first capacitance Cs1 and the second capacitance Cs2.

[0030] In the following description, the anode power line L1 and the cathode power line L10 may be simply referred to as power lines. The video signal line L2, the reset power line L3, and the initialization power line L4 may be referred to as signal lines. The reset control signal line L5, the output control signal line L6, the pixel control signal line L7, and the initialization control signal line L8 may be referred to as gate lines.

[0031] A potential corresponding to the video signal Vsig (or a gradation signal) is supplied to the gate electrode of the drive transistor DRT. That is, the drive transistor DRT supplies a current corresponding to the video signal Vsig to the light-emitting element 3 based on the anode power supply potential PVDD supplied via the output transistor BCT. In this way, the anode power supply potential PVDD supplied to the anode power line L1 is dropped by the drive transistor DRT and the output transistor BCT, so that a potential lower than the anode power supply potential PVDD is supplied to the anode electrode 32 of the light-emitting element 3.

[0032] One electrode of the second capacitance Cs2 is supplied with the anode power supply potential PVDD via the anode power supply line L1, and the other electrode of the second capacitance Cs2 is supplied with a potential lower than the anode power supply potential PVDD. That is, one electrode of the second capacitance Cs2 is supplied with a potential higher than that of the other electrode of the second capacitance Cs2. One electrode of the second capacitance Cs2 is, for example, the counter electrode 26 connected to the anode power supply line L1 shown in FIG. 4, and the other electrode of the second capacitance Cs2 is the anode wiring 23 connected to the source of the drive transistor DRT shown in FIG. 4.

[0033] In the display device 1, the drive circuit 12 (see FIG. 1) selects a plurality of pixel rows in sequence, starting from the top row (for example, the pixel row located at the top in the display area AA in FIG. 1). The drive IC 210 writes a video signal Vsig (video write potential) to the sub-pixels 49 of the selected pixel row, causing the light-emitting element 3 to emit light. For each horizontal scanning period, the drive IC 210 supplies the video signal Vsig to the video signal line L2, supplies a reset power supply potential Vrst to the reset power supply line L3, and supplies an initialization potential Vini to the initialization power supply line L4. In the display device 1, these operations are repeated for each frame of images.

[0034] Next, a cross-sectional configuration of the display device 1 will be described. Fig. 4 is a cross-sectional view taken along line IV-IV' in Fig. 1. As shown in Fig. 4, the light-emitting element 3 is provided on an array substrate 2. The array substrate 2 has a substrate 21, various transistors, various wirings, and various insulating films. The substrate 21 is an insulating substrate, and for example, a glass substrate, a resin substrate, or a resin film is used.

[0035] In this specification, the direction perpendicular to the surface of the substrate 21 from the substrate 21 toward the light-emitting element 3 is referred to as the "upper side" or simply "upper". Also, the direction from the light-emitting element 3 toward the substrate 21 is referred to as the "lower side" or simply "lower".

[0036] The drive transistor DRT and the output transistor BCT are provided on one surface side of the substrate 21. The semiconductor layers 61, 65 are provided on the substrate 21. An undercoat film may be provided between the semiconductor layers 61, 65 and the substrate 21. The insulating film 91 is provided on the substrate 21, covering the semiconductor layers 61, 65. The insulating film 91 is, for example, a silicon oxide film.

[0037] The gate electrodes 64 and 66 are provided on the insulating film 91. In the example shown in Fig. 4, each transistor has a so-called top gate structure. However, each transistor may have a bottom gate structure in which a gate electrode is provided on the lower side of a semiconductor layer, or a dual gate structure in which gate electrodes are provided on both the upper and lower sides of a semiconductor layer.

[0038] The insulating film 92 is provided on the insulating film 91, covering the gate electrodes 64, 66. The insulating film 92 has, for example, a laminated structure of a silicon nitride film and a silicon oxide film. The source electrode 62, the drain electrode 67, and the anode power line L1 are provided on the insulating film 92. The source electrode 62 is electrically connected to the semiconductor layer 61 via a contact hole that penetrates the insulating films 91, 92. In addition, the drain electrode 67 is electrically connected to the semiconductor layer 65 via a contact hole provided in the insulating films 91, 92.

[0039] A plurality of insulating films (first organic insulating film 93, insulating film 94, insulating film 95, and second organic insulating film 96) are provided to cover the respective transistors. The first organic insulating film 93 and the second organic insulating film 96 are made of an organic material such as photosensitive acrylic. Compared to inorganic insulating materials formed by CVD or the like, organic materials such as photosensitive acrylic are superior in coverage of wiring steps and surface flatness. The insulating films 94 and 95 are inorganic insulating films, and may be made of the same material as the insulating films 91 and 92 described above, for example, a silicon nitride film.

[0040] Specifically, the first organic insulating film 93 is provided on the insulating film 92, covering the source electrode 62, the drain electrode 67, and the anode power line L1. The counter electrode 26, the insulating film 94, and the anode wiring 23 are laminated in this order on the first organic insulating film 93. The counter electrode 26 is made of a conductive material having translucency, such as ITO (Indium Tin Oxide). The counter electrode 26 is connected to the anode power line L1 at the bottom of a contact hole CH1 provided in the first organic insulating film 93.

[0041] The insulating film 94 is provided to cover the counter electrode 26. The anode wiring 23 faces the counter electrode 26 via the insulating film 94. Contact holes CH2 and CH3 with the source electrode 62 as the bottom surface are provided in the first organic insulating film 93 and the insulating film 94. The anode wiring 23 is electrically connected to the source electrode 62 via the contact holes CH2 and CH3. As a result, the anode wiring 23 is electrically connected to the drive transistor DRT.

[0042] The anode wiring 23 has, for example, a laminated structure of titanium (Ti) and aluminum (Al). However, without being limited thereto, the anode wiring 23 may have a laminated structure of aluminum (Al) containing one or more metals of molybdenum and titanium. Alternatively, the anode wiring 23 may be an alloy containing one or more of molybdenum and titanium, or a light-transmitting conductive material. In addition, a second capacitance Cs2 is formed between the anode wiring 23 and the counter electrode 26, which face each other via the insulating film 94.

[0043] The insulating film 95 is provided on the insulating film 94, covering the anode wiring 23. The second organic insulating film 96 is provided on the insulating film 95. That is, the first organic insulating film 93 is provided on the drive transistor DRT, and the second organic insulating film 96 is stacked on the upper side of the first organic insulating film 93. The insulating film 95 is provided between the first organic insulating film 93 and the second organic insulating film 96. A contact hole CH4 is provided in the second organic insulating film 96. A contact hole CH5 is provided in the insulating film 95 so as to overlap with the contact hole CH4. The anode wiring 23 is provided at the bottom of the contact holes CH4 and CH5. The anode wiring 23 is provided to face at least a part of the mounting electrode 24.

[0044] The mounting electrode 24 is provided on the second organic insulating film 96, and is electrically connected to the anode wiring 23 via contact holes CH4 and CH5. The mounting electrode 24 has a laminated structure of titanium and aluminum, similar to the anode wiring 23. However, the mounting electrode 24 may be made of a conductive material different from that of the anode wiring 23. Furthermore, the second organic insulating film 96 may be made of an organic material different from that of the first organic insulating film 93.

[0045] The light-emitting element 3 (3R) is mounted on the mounting electrode 24. Although Fig. 4 shows the light-emitting element 3R, other light-emitting elements 3G and 3B (not shown in Fig. 4) are also mounted on the corresponding mounting electrodes 24. Fig. 4 shows a schematic configuration of the light-emitting element 3 and a connection configuration between the light-emitting element 3 and the array substrate 2, and a detailed description will be given later with reference to Figs. 5 and 6.

[0046] The light-emitting element 3 has a semiconductor layer 31, an anode electrode 32, and a cathode electrode 33. The light-emitting element 3 is a flip-chip type light-emitting element in which the anode electrode 32 (p-type electrode) and the cathode electrode 33 (n-type electrode) are provided on the same surface facing the array substrate 2. The light-emitting element 3 has a plurality of anode electrodes 32 and one cathode electrode 33, and one cathode electrode 33 is disposed between the plurality of anode electrodes 32. A connection member 34 is provided to cover the plurality of anode electrodes 32 and the one cathode electrode 33.

[0047] The mounting electrode 24 includes a first mounting electrode 24A facing the anode electrode 32 and a second mounting electrode 24B facing the cathode electrode 33. A columnar conductor 25 for connection is provided on each of the mounting electrodes 24. The columnar conductor 25 is a columnar member extending in a direction perpendicular to the array substrate 2 (substrate 21), and the lower ends (ends on the array substrate 2 side) of the columnar conductors 25 are connected to the mounting electrodes 24, respectively, and the upper ends (ends on the light-emitting element 3 side) of the columnar conductors 25 are connected to the connection member 34. As a result, each of the anode electrodes 32 and one cathode electrode 33 is electrically connected to the mounting electrode 24 via the columnar conductor 25 and the connection member 34.

[0048] A sealant 97 is provided between the plurality of light-emitting elements 3. The sealant 97 is formed of an insulating resin material. The sealant 97 is provided between the lower surface of the light-emitting element 3 and the array substrate 2, and covers the side surface of the light-emitting element 3. The sealant 97 is formed flat so that the upper surface of the sealant 97 and the upper surface of the light-emitting element 3 form the same plane. However, the position of the upper surface of the sealant 97 may be different from the position of the upper surface of the light-emitting element 3, and the sealant 97 may cover the peripheral portion of the upper surface of the light-emitting element 3.

[0049] Fig. 5 is a plan view showing a schematic diagram of a light-emitting element. Fig. 5 shows a plan view of the light-emitting element 3 as seen from its lower surface (i.e., the surface facing the array substrate 2). As shown in Fig. 5, the semiconductor layer 31 of the light-emitting element 3 has a quadrangular shape in plan view. However, the shape is not limited to this, and the semiconductor layer 31 may have other shapes, such as a rectangular shape, a polygonal shape, or a circular shape, in plan view.

[0050] 5, a recess 31a is formed in the center of the lower surface of the light emitting element 3 (semiconductor layer 31). The anode electrode 32 (first electrode) is provided in an area of ​​the lower surface of the semiconductor layer 31 where the recess 31a is not formed. A total of four anode electrodes 32 are provided, one on each side of the semiconductor layer 31. The cathode electrode 33 (second electrode) is provided at the bottom of the recess 31a.

[0051] In plan view, the cathode electrode 33 is disposed between the two anode electrodes 32 in the first direction Dx. Moreover, the cathode electrode 33 is disposed between the two anode electrodes 32 in the second direction Dy.

[0052] The connection members 34 are provided to cover the anode electrode 32 and the cathode electrode 33, respectively. In FIG. 5, the connection members 34 are shown hatched to make the drawing easier to see. The connection members 34 include a first connection member 34a that covers the anode electrode 32, and a second connection member 34b that covers the cathode electrode 33. The first connection member 34a is formed in a ring shape surrounding the second connection member 34b and the cathode electrode 33. The second connection member 34b is formed inside the recess 31a.

[0053] In the following description, when there is no need to distinguish between the first connection member 34a and the second connection member 34b, they will be simply referred to as the connection member 34. In addition, the first connection member 34a is not limited to a configuration formed in a continuous ring shape, and may be provided in a plurality of separate pieces covering each of the plurality of anode electrodes 32.

[0054] With this configuration, the anode electrode 32 and the cathode electrode 33 are arranged symmetrically in the first direction Dx and the second direction Dy, so that even if the cathode electrode 33 is formed in the recess 31a, the light-emitting element 3 can be prevented from being connected at an angle to the array substrate 2.

[0055] Furthermore, the number, shape, and arrangement of the anode electrodes 32 and the cathode electrodes 33 are merely examples and may be changed as appropriate. For example, the number of anode electrodes 32 is not limited to four, and it is sufficient that at least one or more is provided, and five or more may be provided. The shape of the anode electrodes 32 and the cathode electrodes 33 in a plan view is quadrangular, but is not limited thereto, and the anode electrodes 32 and the cathode electrodes 33 may be other shapes, such as rectangular, polygonal, or circular.

[0056] 5, a plurality of fine recesses 38a in the high resistance layer 38 formed on the upper surface of the light emitting element 3 (i.e., the surface opposite to the surface facing the array substrate 2) are indicated by dotted lines. To make the drawing easier to see, only a portion of the fine recesses 38a is shown, but in reality, the fine recesses 38a are arranged over the entire upper surface of the light emitting element 3.

[0057] Fig. 6 is a cross-sectional view showing a schematic connection configuration between a light-emitting element and an array substrate. Fig. 6 is a cross-sectional view taken along the line VI-VI' in Fig. 5, for example. As shown in Fig. 6, the semiconductor layer 31 of the light-emitting element 3 is formed by laminating a high-resistance layer 38, an n-type cladding layer 37, an active layer 36, and a p-type cladding layer 35. The semiconductor layer 31 is formed by laminating the p-type cladding layer 35, the active layer 36, the n-type cladding layer 37, and the high-resistance layer 38 in this order from the array substrate 2 side. The semiconductor layer 31 is made of a compound semiconductor such as gallium nitride (GaN), aluminum indium phosphide (AlInP), or indium gallium nitride (InGaN). The semiconductor layer 31 may be made of different materials for the light-emitting elements 3R, 3G, and 3B.

[0058] For the active layer 36, a multiple quantum well structure (MQW structure) is adopted in which well layers and barrier layers each consisting of several atomic layers are periodically stacked in order to increase efficiency. A recess 31a in the semiconductor layer 31 is formed penetrating the p-type cladding layer 35 and the active layer 36, and the n-type cladding layer 37 is exposed at the bottom of the recess 31a (the surface located on the upper side in the recess 31a in FIG. 6). The cathode electrode 33 is connected to the n-type cladding layer 37 in the recess 31a. The anode electrode 32 is connected to the p-type cladding layer 35 in a region of the lower surface of the semiconductor layer 31 where the recess 31a is not formed.

[0059] The high resistance layer 38 is formed to cover the entire upper surface of the n-type cladding layer 37. The high resistance layer 38 is formed of a semiconductor material (e.g., gallium nitride (GaN)) that is not doped with impurities. The sheet resistance of the high resistance layer 38 is larger than the sheet resistance of the n-type cladding layer 37.

[0060] A plurality of fine recesses 38a are formed on the upper surface of the high resistance layer 38. The fine recesses 38a are formed by transferring the surface shape of a sapphire substrate (see FIG. 9) having a PSS (Patterned Sapphire Substrate) structure. The fine recesses 38a are formed in a hexagonal pyramid shape. That is, in a plan view, the opening shape of each of the fine recesses 38a is a hexagon (see FIG. 5), and the side walls are tapered. By providing the fine recesses 38a, the light emitting element 3 can suppress reflection of external light and suppress deterioration of display quality.

[0061] The fine recesses 38a are not limited to a hexagonal pyramid, and may be of other shapes, such as a cone or a triangular pyramid. The fine recesses 38a are arranged in a matrix in plan view. The fine recesses 38a are not limited to this, and may be arranged in other patterns, such as a triangular lattice. The high resistance layer 38 is not limited to a configuration in which it is provided so as to cover the entire upper surface of the n-type cladding layer 37, and may not be formed on a part of the upper surface of the n-type cladding layer 37.

[0062] The bottom and side surfaces of the light-emitting element 3 are covered with a protective insulating film 39 (e.g., silicon nitride (SiN), aluminum oxide (Al2O3), silicon oxide (SiO2), or the like). The insulating film 39 is formed so as to cover the recess 31a of the semiconductor layer 31. The anode electrode 32 and the cathode electrode 33 are connected to the p-type cladding layer 35 and the n-type cladding layer 37, respectively, through contact holes formed in the insulating film 39.

[0063] As described above, the connection members 34 (first connection member 34a and second connection member 34b) are connected to the anode electrode 32 and the cathode electrode 33, respectively. The width of the first connection member 34a is greater than that of the anode electrode 32. The width of the second connection member 34b is greater than that of the cathode electrode 33. The connection members 34 are formed of a material having a lower hardness (Mohs hardness) than the surrounding metal materials such as the columnar conductors 25, the anode electrode 32, and the cathode electrode 33. The connection members 34 are formed of a metal material containing at least one of tin (Sn) and indium (In), for example.

[0064] The volume of the second connection member 34b is smaller than the volume of the space in the recess 31a of the semiconductor layer 31. The height of the second connection member 34b is smaller than the height of the recess 31a of the semiconductor layer 31. In addition, the width of the second connection member 34b on the bottom side of the recess 31a is smaller than the width of the recess 31a of the semiconductor layer 31. This makes it possible to prevent the second connection member 34b from flowing out of the recess 31a even if the second connection member 34b is made of a flexible material and is deformed in the process of connecting the columnar conductor 25. As a result, it is possible to prevent a short circuit between the second connection member 34b connected to the cathode electrode 33 and the first connection member 34a connected to the anode electrode 32.

[0065] The array substrate 2 is provided with the above-mentioned multiple mounting electrodes 24 (first mounting electrode 24A and second mounting electrode 24B) and multiple columnar conductors 25. Each of the multiple columnar conductors 25 is a columnar member extending in a direction perpendicular to the array substrate 2. The multiple columnar conductors 25 are formed of a material (e.g., tungsten (W)) harder than the multiple connection members 34.

[0066] The columnar conductor 25 includes a first columnar conductor 25A electrically connected to the anode electrode 32 and a second columnar conductor 25B electrically connected to the cathode electrode 33. The lower end (end on the array substrate 2 side) of the first columnar conductor 25A is connected to the first mounting electrode 24A, and the upper end (end on the light-emitting element 3 side) of the first columnar conductor 25A is directly connected to the first connecting member 34a. As a result, the anode electrode 32 is electrically connected to the first mounting electrode 24A. The lower end (end on the array substrate 2 side) of the second columnar conductor 25B is connected to the second mounting electrode 24B, and the upper end (end on the light-emitting element 3 side) of the second columnar conductor 25B is directly connected to the second connecting member 34b. As a result, the cathode electrode 33 is electrically connected to the second mounting electrode 24B.

[0067] In other words, in the region overlapping with the anode electrode 32, the first mounting electrode 24A, the first columnar conductor 25A, the first connecting member 34a, the anode electrode 32, and the semiconductor layer 31 (p-type cladding layer 35) of the light-emitting element 3 are laminated in this order in the direction perpendicular to the array substrate 2. Also, in the region overlapping with the cathode electrode 33, the second mounting electrode 24B, the second columnar conductor 25B, the second connecting member 34b, the cathode electrode 33, and the semiconductor layer 31 (n-type cladding layer 37) of the light-emitting element 3 are laminated in this order in the direction perpendicular to the array substrate 2.

[0068] In this embodiment, the height h1 of the first columnar conductor 25A is smaller than the height h2 of the second columnar conductor 25B. The width of the first columnar conductor 25A is smaller than the width of the first connecting member 34a. A recess is formed in the portion of the first connecting member 34a connected to the first columnar conductor 25A. Similarly, the width of the second columnar conductor 25B is smaller than the width of the second connecting member 34b. A recess is formed in the portion of the second connecting member 34b connected to the second columnar conductor 25B. With this configuration, even if the anode electrode 32 and the cathode electrode 33 of the light-emitting element 3 are formed at different height positions, the connection stability between the anode electrode 32 and the cathode electrode 33 of the light-emitting element 3 and the first mounting electrode 24A and the second mounting electrode 24B of the array substrate 2 can be ensured.

[0069] The difference between the height h1 of the first columnar conductor 25A and the height h2 of the second columnar conductor 25B is set according to the difference in height between the anode electrode 32 and the cathode electrode 33 (i.e., the height of the recess 31a). However, even if there is variation in the heights of the first columnar conductor 25A and the second columnar conductor 25B, since the connecting member 34 is provided with a lower hardness than the first columnar conductor 25A and the second columnar conductor 25B, the connecting member 34 can flexibly deform to absorb the variation in the height of the columnar conductors 25 and ensure connection stability.

[0070] The sealing material 97 is provided between the light-emitting element 3 and the array substrate 2, filling the periphery of the plurality of columnar conductors 25. The sealing material 97 covers the side surface of the light-emitting element 3 and the peripheral portion of the upper surface of the light-emitting element 3. More specifically, the sealing material 97 covers a part of the minute recesses 38a in the peripheral portion of the high-resistance layer 38. This can improve the connection strength between the light-emitting element 3 and the array substrate 2.

[0071] The columnar conductor 25 has a cylindrical or prismatic shape (triangular or rectangular prism shape, etc.), but is not limited thereto and may have other shapes, such as a cone or pyramid shape.

[0072] (First Modification of the First Embodiment) 7 is a cross-sectional view showing a connection configuration between a light-emitting element and an array substrate according to a first modification of the first embodiment. In the following description, the same components as those described in the above embodiment are denoted by the same reference numerals, and duplicated description will be omitted.

[0073] 7, in the display device 1A according to the first modification, a columnar conductor connecting member 28 is provided at the upper end (the end on the light-emitting element 3 side) of the columnar conductor 25. The columnar conductor connecting member 28 is made of a material having a lower hardness than the columnar conductor 25. More preferably, the columnar conductor connecting member 28 is made of the same material as the connecting member 34 of the light-emitting element 3. The columnar conductor connecting member 28 is made of, for example, a metal material containing at least one of tin (Sn) and indium (In).

[0074] First columnar conductor connecting member 28a is provided at the upper end of first columnar conductor 25A, and first columnar conductor connecting member 28a is in contact with first connecting member 34a on the light-emitting element 3 side. Second columnar conductor connecting member 28b is provided at the upper end of second columnar conductor 25B, and second columnar conductor connecting member 28b is in contact with second connecting member 34b on the light-emitting element 3 side. The widths of first columnar conductor connecting member 28a and second columnar conductor connecting member 28b are formed smaller than the widths of first connecting member 34a and second connecting member 34b, respectively.

[0075] In the first modified example, the columnar conductor connecting members 28 and the connecting members 34, which are made of the same material, are in contact with each other, so that the connection stability between the light emitting elements 3 and the array substrate 2 can be improved.

[0076] (Second Modification of the First Embodiment) 8 is a plan view illustrating a light-emitting element according to a second modified example of embodiment 1. A light-emitting element 3A according to the second modified example is different in the number of anode electrodes 32 from the light-emitting element 3 according to the above-described first embodiment.

[0077] 8, two anode electrodes 32 are arranged side by side in the first direction Dx, and the cathode electrode 33 is disposed between the anode electrodes 32 adjacent to each other in the first direction Dx. The first connection member 34a extends in the second direction Dy, covering each of the anode electrodes 32. The anode electrode 32 and the first connection member 34a are not provided in a position adjacent to the cathode electrode 33 on the second direction Dy side.

[0078] In the second modified example as well, the anode electrodes 32 and the cathode electrodes 33 are disposed symmetrically at least in the first direction Dx, so that connection to the array substrate 2 at an angle can be prevented.

[0079] (Display Device Manufacturing Method) Fig. 9 is a flowchart for explaining the method for manufacturing the display device according to the first embodiment. As shown in Fig. 9, the method for manufacturing the display device includes a light-emitting element forming step (steps ST11 to ST14) and an array substrate forming step (steps ST15 to ST17).

[0080] In the light emitting device forming process, the manufacturing equipment forms a semiconductor layer 31 on a sapphire substrate (step ST11). Specifically, the manufacturing equipment forms a high resistance layer 38, an n-type cladding layer 37, an active layer 36, and a p-type cladding layer 35 in this order on one surface of the sapphire substrate. In addition, a PSS structure is formed on one surface of the sapphire substrate.

[0081] Next, the manufacturing equipment patterns the semiconductor layer 31 to form recesses 31a, and forms an insulating film 39, an anode electrode 32 (first electrode) and a cathode electrode 33 (second electrode) having different polarities (step ST12). However, the anode electrode 32 and the cathode electrode 33 may be made of different materials. As described above, the anode electrode 32 is provided in an area of ​​the semiconductor layer 31 where the recesses 31a are not formed. The cathode electrode 33 is provided in an area of ​​the semiconductor layer 31 where the recesses 31a are formed.

[0082] Next, the manufacturing equipment forms the connection members 34 to cover the anode electrodes 32 and the cathode electrodes 33 (step ST13).

[0083] Next, the manufacturing equipment transfers the light emitting element 3 on the sapphire substrate to the carrier substrate 200 by laser lift-off or the like (step ST14). FIG. 10 is a cross-sectional view that shows a schematic diagram of the light emitting element in step ST14 of FIG. 9. As shown in FIG. 10, the light emitting element 3 is transferred from the sapphire substrate at least twice, and the high resistance layer 38, the n-type cladding layer 37, the active layer 36, and the p-type cladding layer 35 are arranged on the carrier substrate 200 in this order. In the light emitting element forming step, the connection member 34 is located on the outermost surface of the light emitting element 3, and the columnar conductor 25 is not formed on the light emitting element 3. Therefore, the transfer step can be performed more easily than when the columnar conductor 25 is formed on the light emitting element 3 side. Alternatively, damage to the columnar conductor 25 in the transfer step can be suppressed compared to when the columnar conductor 25 is formed on the light emitting element 3 side.

[0084] In the array substrate forming process, first, the manufacturing equipment forms each transistor such as the drive transistor DRT and each wiring on the substrate 21 (step ST15).

[0085] Next, the manufacturing equipment forms a plurality of mounting electrodes 24 (first mounting electrodes 24A and second mounting electrodes 24B) on the array substrate 2 (step ST16). The first mounting electrodes 24A and the second mounting electrodes 24B are patterned in accordance with the arrangement of the anode electrodes 32 and the cathode electrodes 33 of the light-emitting elements 3.

[0086] Next, the manufacturing equipment forms columnar conductors 25 (first columnar conductor 25A and second columnar conductor 25B) on a plurality of mounting electrodes 24 (first mounting electrode 24A and second mounting electrode 24B) provided on the array substrate 2 (step ST17). Fig. 11 is a cross-sectional view showing a schematic view of the array substrate at step ST17 in Fig. 9. The first columnar conductor 25A and the second columnar conductor 25B are formed to different heights h1 and h2, respectively, corresponding to the height positions of the anode electrode 32 and the cathode electrode 33 of the light-emitting element 3.

[0087] Next, the manufacturing equipment forms a sealant 97 on the array substrate 2 so as to cover the plurality of columnar conductors 25 (step ST18). The sealant 97 is made of an uncured resin material (for example, epoxy resin).

[0088] Next, the manufacturing equipment arranges the carrier substrate 200 (see FIG. 10) on which the light-emitting element 3 is formed and the array substrate 2 (see FIG. 11) on which the columnar conductors 25 are formed so as to face each other, and applies pressure to transfer the light-emitting element 3 from the carrier substrate 200 to the array substrate 2 (step ST19). This connects the columnar conductors 25 of the array substrate 2 and the connecting members 34 of the light-emitting element 3.

[0089] 6 and 10, the side surface of the light emitting element 3 and the side surface of the recess 31a are each formed to be inclined. Therefore, when the light emitting element 3 is transferred onto the array substrate 2 covered with the sealing material 97, the sealing material 97 flows along the side surface of the light emitting element 3 and the side surface of the recess 31a. As a result, after the transfer, the sealing material 97 covers the side surface of the light emitting element 3 and is satisfactorily filled in the recess 31a.

[0090] Next, the manufacturing equipment drives the pixel circuits PICA (see FIG. 3) of the array substrate 2 while the sealing material 97 is in an uncured state, and performs a lighting inspection of the light-emitting elements 3 (step ST20). If any light-emitting element 3 does not light up, it is replaced with another light-emitting element 3 and repaired.

[0091] Next, after the lighting inspection and repair are completed, a current larger than the current used during the lighting inspection is passed through the light-emitting element 3 to light it up (step ST21). As a result, the sealant 97 is hardened by the heat of the light-emitting element 3 that is turned on. At this time, only the sealant 97 around the light-emitting element 3 that is turned on is hardened, and the sealant 97 formed in the area where the light-emitting element 3 is not mounted remains unhardened. For example, among the light-emitting elements 3R, 3G, and 3B, when the light-emitting element 3R is mounted and the light-emitting elements 3G and 3B are not mounted, in step ST21, only the sealant 97 around the light-emitting element 3R is hardened. The sealant 97 in the area corresponding to the light-emitting elements 3G and 3B remains unhardened. In step ST21, the value of the current flowing through the light-emitting element 3 is set so that the heat of the light-emitting element 3 is in a range of not less than the temperature at which the sealant 97 is hardened (for example, about 140° C. to 160° C.) and not more than the melting point of the connection member 34 (for example, about 200° C.).

[0092] Next, the manufacturing equipment repeatedly executes steps ST19 to ST21 for each of the light-emitting elements 3R, 3G, and 3B (step ST22).

[0093] In this way, by passing a current through the light-emitting element 3 and hardening the sealant 97 by utilizing the heat of the light-emitting element 3, it is possible to easily perform a lighting inspection and repair of the light-emitting element 3. That is, in a method in which the light-emitting element 3 is mounted and the entire sealant 97 is hardened before performing a lighting inspection, it is difficult to remove a defective light-emitting element 3 from the array substrate 2, whereas in this embodiment, it is possible to harden the sealant 97 for each non-defective light-emitting element 3, and the sealant 97 is not hardened around the defective light-emitting element 3. As a result, the manufacturing method of the display device 1 of this embodiment makes it possible to easily perform a lighting inspection and repair of the light-emitting element 3.

[0094] It should be noted that the manufacturing method shown in FIG. 9 is merely an example and can be modified as appropriate.

[0095] As described above, the display device 1 of the present embodiment includes the array substrate 2, a plurality of mounting electrodes 24 provided on the array substrate 2, a columnar conductor 25 for connection provided on each of the plurality of mounting electrodes 24, a plurality of light-emitting elements 3 provided on the array substrate 2, a first electrode (e.g., anode electrode 32) provided on a surface of the plurality of light-emitting elements 3 facing the array substrate 2 and connected to one of the anode and cathode of the light-emitting elements 3, a second electrode (e.g., cathode electrode 33) connected to the other of the anode and cathode of the light-emitting elements 3, and a connection member 34 covering each of the first electrode and the second electrode. The columnar conductor 25 is made of a material harder than the connection member 34, and an end of the columnar conductor 25 on the light-emitting element 3 side is electrically connected to the connection member 34.

[0096] In addition, the manufacturing method of the display device 1 of this embodiment includes the steps of forming an anode electrode 32 (first electrode) and a cathode electrode 33 (second electrode) of opposite polarity on one surface of the light-emitting element 3, and forming a connection member 34 covering each of the anode electrode 32 (first electrode) and the cathode electrode 33 (second electrode) (steps ST12, ST13), forming a plurality of mounting electrodes 24 on the array substrate 2, and forming a columnar conductor 25 for connection on each of the plurality of mounting electrodes 24 (steps ST16, ST17), and applying pressure to the light-emitting element 3 to electrically connect the columnar conductor 25 and the connection member 34.

[0097] According to this, since the columnar conductors 25 for connection are provided on the array substrate 2 side, the transfer step can be performed more easily than when the columnar conductors 25 are formed on the light-emitting element 3 side. Also, compared to when the columnar conductors 25 are formed on the light-emitting element 3 side, damage to the columnar conductors 25 can be suppressed even when the transfer step is repeated multiple times. Therefore, the display device 1 can ensure connection stability.

[0098] Second embodiment Fig. 12 is a cross-sectional view showing a connection between the light-emitting element and the array substrate according to the second embodiment. As shown in Fig. 12, in the display device 1B according to the second embodiment, an anisotropic conductive film 70 (ACF) is provided between the array substrate 2 and the light-emitting element 3 instead of the columnar conductor 25.

[0099] The anisotropic conductive film 70 includes an insulating resin material 71 and conductive particles 72 dispersed in the insulating resin material 71. The conductive particles 72 include first conductive particles 72a and second conductive particles 72b having different particle sizes. The particle size of the first conductive particles 72a is smaller than the particle size of the second conductive particles 72b. The first conductive particles 72a are disposed on the first mounting electrode 24A and connected to the first connection member 34a of the light-emitting element 3. As a result, the anode electrode 32 is electrically connected to the first mounting electrode 24A via the first connection member 34a and the first conductive particles 72a.

[0100] The second conductive particles 72b are disposed on the second mounting electrode 24B and connected to the second connection member 34b of the light emitting element 3. As a result, the cathode electrode 33 is electrically connected to the second mounting electrode 24B via the second connection member 34b and the second conductive particles 72b.

[0101] In other words, in the region overlapping with the anode electrode 32, the first mounting electrode 24A, the first conductive particles 72a, the first connecting member 34a, the anode electrode 32, and the semiconductor layer 31 (p-type cladding layer 35) of the light-emitting element 3 are laminated in this order in the direction perpendicular to the array substrate 2. Also, in the region overlapping with the cathode electrode 33, the second mounting electrode 24B, the second conductive particles 72b, the second connecting member 34b, the cathode electrode 33, and the semiconductor layer 31 (n-type cladding layer 37) of the light-emitting element 3 are laminated in this order in the direction perpendicular to the array substrate 2.

[0102] The conductive particles 72 (first conductive particles 72a and second conductive particles 72b) are made of a material harder than the connection members 34 (first connection members 34a and second connection members 34b). Therefore, a recess is formed in a portion of the first connection member 34a connected to the first conductive particles 72a. Also, a recess is formed in a portion of the second connection member 34b connected to the second conductive particles 72b. This increases the contact area between the conductive particles 72 and the connection members 34, ensuring connection stability.

[0103] In the process of transferring the light-emitting element 3 to the array substrate 2 (see step ST19 in FIG. 9), pressure is applied to each conductive particle 72 between the light-emitting element 3 and the array substrate 2, whereby the conductive particles 72 are deformed. After the light-emitting element 3 is mounted, the height h1a of the first conductive particles 72a is smaller than the height h2a of the second conductive particles 72b. In addition, the width of the first conductive particles 72a is smaller than the width of the second conductive particles 72b. In other words, the particle size of the first conductive particles 72a overlapping the anode electrode 32 is smaller than the particle size of the second conductive particles 72b overlapping the cathode electrode 33. With this configuration, even if the anode electrode 32 and cathode electrode 33 of the light-emitting element 3 are formed at different height positions, by arranging the first conductive particles 72a and the second conductive particles 72b of the anisotropic conductive film 70 on the first mounting electrode 24A and the second mounting electrode 24B, respectively, it is possible to ensure the stability of the connection between the anode electrode 32 and the cathode electrode 33 of the light-emitting element 3 and the first mounting electrode 24A and the second mounting electrode 24B of the array substrate 2.

[0104] The insulating resin material 71 is formed of an insulating material and is provided around the conductive particles 72 between the array substrate 2 and the plurality of light-emitting elements 3. The insulating resin material 71 also functions as a sealant. The upper surface 71a of the insulating resin material 71 coincides with the upper surface of the light-emitting element 3. However, this is not limited, and the upper surface 71a of the insulating resin material 71 may be in a position shifted from the upper surface of the light-emitting element 3. For ease of understanding, FIG. 12 shows a configuration in which one conductive particle 72 is disposed on one mounting electrode 24. However, this is not limited, and a plurality of conductive particles 72 may be aggregated on one mounting electrode 24.

[0105] (Third modified example of the second embodiment) Fig. 13 is a cross-sectional view showing a connection configuration between a light-emitting element and an array substrate according to a third modified example of the second embodiment. As shown in Fig. 13, in a display device 1C according to the third modified example of the second embodiment, a mounting electrode connection member 29 is provided on a mounting electrode 24. The mounting electrode connection member 29 is formed of a material having a lower hardness than the conductive particles 72. More preferably, the columnar conductor connection member 28 is formed of the same material as the connection member 34 of the light-emitting element 3. The mounting electrode connection member 29 is formed of a metal material containing at least one of tin (Sn) and indium (In), for example.

[0106] More specifically, a first mounting electrode connecting member 29a is provided on the first mounting electrode 24A. The first conductive particles 72a are provided between the first mounting electrode connecting member 29a on the array substrate 2 side and the first connecting member 34a on the light-emitting element 3 side. In addition, a second mounting electrode connecting member 29b is provided on the second mounting electrode 24B. The second conductive particles 72b are provided between the second mounting electrode connecting member 29b on the array substrate 2 side and the second connecting member 34b on the light-emitting element 3 side.

[0107] In the third modification, the mounting electrode connecting member 29 and the connecting member 34 made of the same material are in contact with each other in the vertical direction of the conductive particles 72, so that the pressure applied to the conductive particles 72 during mounting of the light-emitting element 3 is alleviated. Therefore, in the third modification, the height h1b of the first conductive particles 72a and the height h2b of the second conductive particles 72b after mounting of the light-emitting element 3 are maintained to be greater than the height h1a of the first conductive particles 72a and the height h2a of the second conductive particles 72b in the second embodiment described above. As a result, in the third modification, unintended deformation of the conductive particles 72 can be suppressed, and short-circuiting of adjacent mounting electrodes 24 can be suppressed. Therefore, the connection stability between the light-emitting element 3 and the array substrate 2 can be improved.

[0108] Fig. 14 is an explanatory diagram for explaining a step of forming an anisotropic conductive film in the manufacturing method of the display device according to the second embodiment. The manufacturing method of the display device 1B of the second embodiment and the display device 1C according to the third modification can employ a flow similar to that of Fig. 9 described above. However, instead of the step of forming the columnar conductor 25 in Fig. 9 (step ST17), the step (step ST17A) shown in Fig. 14 is performed. Also, the step of forming the sealing material 97 in Fig. 9 (step ST18) is omitted.

[0109] 14, in the manufacturing method of the second embodiment, an anisotropic conductive film 70 is formed on the array substrate 2 on which the mounting electrodes 24 are provided (step ST17A). When forming the anisotropic conductive film 70, the first conductive particles 72a having a small particle size are arranged on the first mounting electrodes 24A, and the second conductive particles 72b having a large particle size are arranged on the second mounting electrodes 24B. An insulating resin material 71 is provided on the array substrate 2, covering the first conductive particles 72a and the second conductive particles 72b.

[0110] 9 and subsequent steps are performed, whereby the light-emitting element 3 is mounted on the array substrate 2 via the first conductive particles 72a and the second conductive particles 72b of the anisotropic conductive film 70. The lighting inspection and repair shown in steps ST20 and ST21 in FIG. 9 can also be applied to the display devices 1B and 1C of the second embodiment.

[0111] Although the preferred embodiment of the present invention has been described above, the present invention is not limited to such an embodiment. The contents disclosed in the embodiment are merely examples, and various modifications are possible within the scope of the present invention. Appropriate modifications made within the scope of the present invention naturally belong to the technical scope of the present invention. At least one of various omissions, substitutions, and modifications of components can be made within the scope of the gist of each of the above-mentioned embodiments and each modified example. [Explanation of symbols]

[0112] 1, 1A, 1B, 1C display device 2 Array Board 3, 3A, 3R, 3G, 3B Light-emitting element 12 Drive circuit 21 Substrate 24 Mounting electrode 25 Pillar Conductor 26 Counter electrode 28 Pillar conductor connection member 29 Mounting electrode connection material 31 Semiconductor layer 31a Recess 32 Anode electrode 33 Cathode Electrode 34 Connection parts 35 p-type cladding layer 36 Active layer 37 n-type cladding layer 38 High resistance layer 38a Micro recess 39 Insulating Film 70 Anisotropic Conductive Film 71 Insulating resin materials 72 Conductive Particles 97 Encapsulating materials

Claims

1. An array substrate; A plurality of mounting electrodes provided on the array substrate; a columnar conductor for connection provided on each of the plurality of mounting electrodes; A plurality of light emitting elements provided on the array substrate; a first electrode provided on a surface of the plurality of light-emitting elements facing the array substrate, the first electrode being connected to one of the anode and the cathode of the light-emitting element, and a second electrode being connected to the other of the anode and the cathode of the light-emitting element; a connection member covering each of the first electrode and the second electrode, the columnar conductor is made of a material harder than the connection member, and an end of the columnar conductor on the side of the light emitting element is electrically connected to the connection member; A plurality of the first electrodes are provided. the second electrode is disposed in a recess formed on a surface of the light-emitting element facing the array substrate, the second electrode is disposed between a plurality of the first electrodes in a plan view from a surface of the light-emitting element facing the array substrate; the columnar conductor includes a first columnar conductor electrically connected to the first electrode and a second columnar conductor electrically connected to the second electrode; The height of the first columnar conductor is smaller than the height of the second columnar conductor. Display device.

2. The mounting electrode, the columnar conductor, the connection member, the first electrode, or the second electrode are laminated in this order in a direction perpendicular to the array substrate. The display device according to claim 1 .

3. a sealing material provided between the array substrate and the plurality of light emitting elements and made of an insulating material; The sealing material is provided to cover the peripheral portion of the upper surface of the light-emitting element. The display device according to claim 1 or 2.

4. an end of the columnar conductor on the side of the light emitting element is directly connected to the connection member; A recess is formed in a portion of the connection member that is connected to the columnar conductor. The display device according to claim 1 .

5. An array substrate; A plurality of mounting electrodes provided on the array substrate; a columnar conductor for connection provided on each of the plurality of mounting electrodes; A plurality of light emitting elements provided on the array substrate; a first electrode provided on a surface of the plurality of light-emitting elements facing the array substrate, the first electrode being connected to one of the anode and the cathode of the light-emitting element, and a second electrode being connected to the other of the anode and the cathode of the light-emitting element; a connection member covering each of the first electrode and the second electrode, the columnar conductor is made of a material harder than the connection member, and an end of the columnar conductor on the side of the light emitting element is electrically connected to the connection member; an end of the columnar conductor on the side of the light emitting element is directly connected to the connection member; A recess is formed in a portion of the connection member that is connected to the columnar conductor. Display device.

6. a columnar conductor connecting member made of a material having a lower hardness than the columnar conductor is provided at an end of the columnar conductor on the side of the light emitting element; The columnar conductor connecting member is in contact with the connecting member provided on the light emitting element. The display device according to claim 1 .

7. An array substrate; A plurality of mounting electrodes provided on the array substrate; a columnar conductor for connection provided on each of the plurality of mounting electrodes; A plurality of light emitting elements provided on the array substrate; a first electrode provided on a surface of the plurality of light-emitting elements facing the array substrate, the first electrode being connected to one of the anode and the cathode of the light-emitting element, and a second electrode being connected to the other of the anode and the cathode of the light-emitting element; a connection member covering each of the first electrode and the second electrode, the columnar conductor is made of a material harder than the connection member, and an end of the columnar conductor on the side of the light emitting element is electrically connected to the connection member; a columnar conductor connecting member made of a material having a lower hardness than the columnar conductor is provided at an end of the columnar conductor on the side of the light emitting element, The columnar conductor connecting member is in contact with the connecting member provided on the light emitting element. Display device.

8. The connection member contains at least one of tin (Sn) and indium (In). The display device according to claim 1 .

9. forming a first electrode and a second electrode having different polarities on one surface of a light-emitting element, and forming a connection member covering each of the first electrode and the second electrode; forming a plurality of mounting electrodes on an array substrate and forming connecting columnar conductors on each of the plurality of mounting electrodes; applying pressure to the light emitting element to electrically connect the columnar conductor and the connection member; forming a sealant on the array substrate to cover the columnar conductors for connection after the step of forming the columnar conductors for connection and before the step of connecting the light emitting elements; and after the step of connecting the light-emitting element, a step of applying a current to the light-emitting element to harden the sealing material around the light-emitting element. A method for manufacturing a display device.

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