Display device

Abstract

Display device (10B), comprising: a substrate (100); an organic insulating layer (170B) over the substrate (100); an inorganic insulating layer (172B) with a predetermined pattern over the organic insulating layer (170B); a metal layer (190B) over the inorganic insulating layer (172B); and a light-emitting element (200) over the metal layer (190B), wherein the inorganic insulating layer (172B) overlaps the light-emitting element (200) and the metal layer (190B) covers the inorganic insulating layer (172B) and comprises a step section along a side face of the inorganic insulating layer (172B).

Description

[Technical area]

[0001] The present invention relates to a display device, in particular a display device that uses a micro-LED. [Background art]

[0002] In small to medium-sized display devices such as smartphones, displays using liquid crystals or OLEDs (Organic Light Emitting Diodes) have become commercially available. In particular, an OLED display device, which uses OLEDs that are self-illuminating elements, offers the advantages of high contrast and does not require backlighting compared to a liquid crystal display device. However, because OLEDs are made of organic compounds, ensuring high reliability of the OLED display device is challenging due to the degradation of these compounds.

[0003] On the other hand, a so-called micro-LED display has been developed as a next-generation display. In this type of display, pixels are arranged in a matrix, and tiny micro-LEDs are placed within each pixel. Micro-LEDs are self-emissive elements similar to OLEDs, but unlike OLEDs, micro-LEDs are made of inorganic compounds containing gallium (Ga) or indium (In). Therefore, compared to OLED displays, it is easier to ensure a highly reliable micro-LED display. Furthermore, micro-LEDs have high luminous efficacy and high brightness. Thus, the micro-LED display is expected to be the next-generation display, offering high reliability, high brightness, and high contrast.

[0004] Similar to conventional LEDs, micro-LEDs are formed on a substrate such as sapphire and separated into individual micro-LEDs by cutting the substrate. As described above, in the micro-LED display, the cubed micro-LEDs are transferred and bonded into the pixels of a display substrate (for example, patent literature 1).

[0005] Furthermore, patent literature 2 describes a method for manufacturing a display device, comprising a step for forming a sublayer on a substrate, wherein the sublayer has a projection, and a step for applying a lens section material to form a film whose shape follows the shape of the sublayer.

[0006] Patent literature 3 describes a light-emitting device. This comprises a light-emitting element and a wiring substrate with a substrate body having a projecting section at a position where the light-emitting device is arranged, as well as wiring patterns arranged on the substrate body and electrically connected to the light-emitting element.

[0007] Patent literature 4 describes a display device. This comprises a substrate, a first light-emitting diode (LED) arranged on the substrate and emitting a first light, a second LED arranged on the substrate and emitting a second light, a first cover layer arranged on the first LED, and a second cover layer arranged on the second LED and having optical properties that differ from those of the first cover layer. [List of citations][Patent literature] Patent literature 1: US 2017 / 0 288 102 A1 Patent literature 2: US 2012 / 0 305 950 A1 Patent literature 3: US 2008 / 0 030 139 A1 Patent literature 4: US 2017 / 0 242 549 A1 [Summary of the invention][Problems to be solved by the invention]

[0008] However, if the adhesion between the metal layer to which the micro-LED is bonded and the organic insulating layer beneath the metal layer is weak, the metal layer may detach due to heat during treatment at the time of bonding at the interface between the metal layer and the organic insulating layer.

[0009] In light of the problems mentioned above, one object of the present invention is to reduce the stress on the metal layer to which the light-emitting layer of the display device is bonded and to suppress delamination at the interface between the metal layer and the organic insulating layer. A further object of the present invention is to improve the reliability of the display device. [Solution to solve the problems]

[0010] This problem is solved, among other things, by a display device according to claim 1. Further embodiments are the subject of the dependent claims. [Brief description of the drawings] Fig. Figure 1 is a schematic cross-sectional view of a display device according to an embodiment of the present invention. Fig. Figure 2A is a schematic, partially enlarged view of a display device according to an embodiment of the present invention. Fig. Figure 2B is a schematic top view of a display device according to an embodiment of the present invention. Fig. Figure 3 is a schematic, partially enlarged view of a display device according to an embodiment of the present invention. Fig. Figure 4 is a schematic, partially enlarged view of a display device according to an embodiment of the present invention. Fig. Figure 5 is a schematic top view of a display device according to an embodiment of the present invention. Fig. Figure 6A is a schematic, partially enlarged view of a display device according to a method for manufacturing a display device according to an embodiment of the present invention. Fig. Figure 6B is a schematic, partially enlarged view of the display device in the method for manufacturing the display device according to the embodiment of the present invention. Fig. Figure 6C is a schematic, partially enlarged view of the display device in the method for manufacturing the display device according to the embodiment of the present invention. [Description of the embodiments]

[0011] Exemplary embodiments of the present invention are described below with reference to the drawings. For the sake of clarity, the drawings may be presented schematically with respect to the widths, thicknesses, shapes, and the like of the respective sections in comparison to actual embodiments. However, the shapes shown are merely examples and are not intended to limit the interpretation of the present invention.

[0012] In the present description, the expressions “α includes A, B or C”, “α includes one of A, B and C”, and “α includes one selected from the group consisting of A, B and C” do not exclude the case where α includes several combinations of A to C, unless otherwise specified. Furthermore, these expressions do not exclude the case where α contains other elements.

[0013] In the present description, although the terms "above" or "upper direction" or "lower direction" are used for the sake of simplicity, the direction from a substrate to a structure is, in principle, referred to as "above" or "upper direction" with respect to a substrate in which the structure is formed. Conversely, the direction from the structure to the substrate is referred to as "below" or "under." Therefore, in the expression of a light-emitting element above a substrate, one surface of the light-emitting element in the direction facing the substrate is the lower surface of the light-emitting element, and the other surface is the upper surface of the light-emitting element.Furthermore, the expression "a light-emitting element above a substrate" only describes the vertical relationship between the substrate and the light-emitting element, and another element may be positioned between the substrate and the light-emitting element. Moreover, the terms "above" or "above the direction" or "below" or "below the direction" refer to the order of the stacked layers in the structure, where a multitude of layers are stacked, and do not necessarily refer to the position of the layers overlapping in a top view.

[0014] In this description, "display device" is intended to encompass a wide range of devices that display a still image or moving images using the light-emitting element, and may include not only a display field and a display module, but also a device to which other optical elements (e.g., a polarizing element or a touch field, etc.) are attached.

[0015] The following examples of implementation can be combined with each other, as long as there is no technical contradiction. <First embodiment>

[0016] A display device 10 according to an embodiment of the present invention is described with reference to the Fig. 1 and Fig. 2 described. [Display device configuration 10]

[0017] Fig. Figure 1 is a schematic cross-sectional view of a display device 10 according to an embodiment of the present invention. In particular, Fig. 1 a cross-sectional view cut to include pixels of the display device 10.

[0018] As in Fig. As shown in Figure 1, the display device 10 includes a substrate 100, a first wiring layer 110, a second wiring layer 120, a first insulating layer 130, a second conductive layer 140, a second insulating layer 150, a first conductive layer 160, an organic insulating layer 170, a first connecting electrode 180, a metal layer 190, a light-emitting element 200, a leveling layer 250 and a second connecting electrode 210.

[0019] The first wiring layer 110 and the second wiring layer 120 are provided on the substrate 100. The first insulating layer 130, the second conductive layer 140, the second insulating layer 150, and the first conductive layer 160 are stacked in that order above the first wiring layer 110 and the second wiring layer 120. Above the first wiring layer 110, the first insulating layer 130 and the second insulating layer 150 are open, and the first conductive layer 160 is electrically connected to the first wiring layer 110 through the openings in the first insulating layer 130 and the second insulating layer 150. Furthermore, above the second wiring layer 120, the first insulating layer 130 is open, and the second conductive layer 140 is electrically connected to the second wiring layer 120 through the opening in the first insulating layer 130.

[0020] Furthermore, the organic insulating layer 170 is provided with an opening above the second insulating layer 150 and the first conductive layer 160. A first connecting electrode 180 is provided in the opening of the organic insulating layer 170, and the first connecting electrode 180 is electrically connected to the first conductive layer 160 through the opening of the organic insulating layer 170. A metal layer 190 is provided on the first connecting electrode 180, and the metal layer 190 is electrically connected to the first connecting electrode 180. A light-emitting element 200 is provided on the metal layer 190. A second connecting electrode 210 is provided on the light-emitting element 200. The space between the organic insulating layer 170 and the second connecting electrode 210 can be filled with an organic resin for the leveling layer 250.

[0021] Substrate 100 can support any layer above it. For example, a flexible substrate such as a polyimide substrate, an acrylic substrate, a siloxane substrate, a fluorinated resin substrate, or the like can be used as substrate 100. Impurities can be introduced into the flexible substrate to improve its heat resistance. If transparency is not required, impurities that reduce its transparency can be used. Conversely, if flexibility is not required, a rigid, transparent substrate such as a glass substrate, a quartz substrate, or a sapphire substrate can be used as substrate 100.Furthermore, substrate 100 can be a non-transparent substrate, such as a silicon substrate, a silicon carbide substrate, a semiconductor substrate, such as a compound semiconductor substrate, or a conductive substrate, such as a stainless steel substrate. Additionally, substrate 100 can also be a substrate on which a silicon oxide film or a silicon nitride film is formed.

[0022] A single metal material can be used for each of the following: the first wiring layer 110, the second wiring layer 120, the first conductive layer 160, the second conductive layer 140, and the first connecting electrode 180. While the metal material could be, for example, copper (Cu), aluminum (Al), titanium (Ti), chromium (Cr), cobalt (Co), nickel (Ni), molybdenum (Mo), hafnium (Hf), tantalum (Ta), tungsten (W), bismuth (Bi), or alloys or compounds thereof, the metal material is not limited to these. Furthermore, the first wiring layer 110, the second wiring layer 120, the first conductive layer 160, the second conductive layer 140, or the first connecting electrode 180 could have a structure in which the aforementioned metal materials are stacked.

[0023] One insulating material can be used for each of the first insulating layer 130 and the second insulating layer 150. The insulating material could be, for example, an inorganic insulating material such as silicon dioxide (SiO₂). x ), silicon oxynitride (SiO₂) x Ny), silicon nitride (SiN x ), silicon nitride oxide (SiN x O y ), aluminum oxide (AlO x ), Aluminum oxynitride (AlO x N y ), aluminum nitride oxide (AlN x O y ), Aluminum nitride (AlN x ) or the like, the insulating material is not limited to these. Here, SiO₂ is used. x N y and AlO x N y Silicon compounds and aluminum compounds containing nitrogen in a smaller amount than oxygen. Furthermore, SiN x O y and AlN x O ySilicon compounds and aluminum compounds containing oxygen in a lower quantity than nitrogen. Furthermore, not only the above-mentioned inorganic insulating material, but also an organic insulating material can be used for both the first insulating layer 130 and the second insulating layer 140. Although the organic insulating material is, for example, a resin such as a polyimide resin, an acrylic resin, an epoxy resin, a silicone resin, a fluorinated resin, a siloxane resin, or the like, the organic insulating material is not limited to these. Furthermore, the first insulating layer 130 and the second insulating layer 140 can have a structure in which the inorganic material or the organic material can be used alone or stacked together.

[0024] The organic insulating layer 170 can smooth a step in the layer below it. The material of the organic insulating layer 170 can be a photosensitive organic material, such as a photosensitive acrylic resin or a photosensitive polyimide resin. Alternatively, the material of the organic insulating layer 170 can be the same inorganic insulating material used for the first insulating layer 130 and the second insulating layer 150. Furthermore, the organic insulating layer 170 can have a stacked structure. For example, the organic insulating layer 170 can have a stacked structure of the photosensitive organic material and the inorganic insulating material, or a stacked structure of the organic insulating material and the inorganic insulating material.

[0025] A convex section 171 is provided on an upper surface of the organic insulating layer 170. For example, the height of the convex section 171 (the distance from the upper surface of a section of the organic insulating layer 170 where the convex section 171 is not provided (hereinafter simply referred to as the upper surface of the organic insulating layer 170) to an upper surface of the convex section 171) is greater than or equal to 0.2 µm and less than or equal to 10.0 µm. The height of the organic insulating layer 170 is preferably greater than or equal to 1 / 2 the thickness of the metal layer 190, more preferably a height greater than the thickness of the metal layer 190.

[0026] One side face of the convex section 171 may be tapered. That is, the side face of the convex section 171 need not be perpendicular to the upper surface of the organic insulating layer 170. The angle formed by the upper surface of the organic insulating layer 170 and the side face of the convex section 171 is, for example, greater than or equal to 20 degrees and less than or equal to 90 degrees, preferably greater than or equal to 30 degrees and less than or equal to 80 degrees, and more preferably greater than 40 degrees and less than or equal to 70 degrees.

[0027] Furthermore, the shape of the convex section 171 can be circular, elliptical, or polygonal in a top view. Preferably, the shape of the convex section 171 corresponds to the shape of the light-emitting element 200. For example, if the shape of the light-emitting element 200 is rectangular, it is preferred that the shape of the convex section 171 is also rectangular.

[0028] The metal layer 190 can reflect the light emitted by the light-emitting element 200. Furthermore, the metal layer 190 is conductive enough to electrically connect an electrode of the light-emitting element 200 and the first connecting electrode 180. For example, a metallic material with high reflectivity, such as aluminum (Al), silver (Ag), or platinum (Pt), is preferably used as the material of the metal layer 190. Additionally, metallic materials used for the first wiring layer 110, the second wiring layer 120, the first conductive layer 160, the second conductive layer 140, and the first connecting electrode 180 can also be used as the material of the metal layer 190.

[0029] The metal layer 190 is provided such that it covers the convex section 171 of the organic insulating layer 170. That is, the metal layer 190 is provided such that it overlaps a top surface and the side surface of the convex section 171. The thickness of the metal layer 190 is, for example, greater than or equal to 0.2 µm and less than or equal to 3 µm, preferably greater than or equal to 0.5 µm and less than or equal to 2 µm, and particularly preferably greater than or equal to 0.5 µm and less than or equal to 0.75 µm. If the thickness of the metal layer 190 is small, not only will its resistance be high, but it will also be difficult to relieve the stress on the metal layer 190. Furthermore, if the thickness of the metal layer 190 is large, it takes time to form and process the metal layer 190, thus increasing the cycle time for manufacturing the display device 10. Therefore, the thickness of the metal layer 190 is preferably in the range above.

[0030] For example, the light-emitting element 200 is a light-emitting diode (LED) or a laser diode (LD). Furthermore, the light-emitting diode contains a mini-LED or a micro-LED.

[0031] The light-emitting element 200 is provided in each pixel of the display device, and each pixel also contains a red light-emitting element, a green light-emitting element, and a blue light-emitting element. By combining the red light emission from the red light-emitting element, the green light emission from the green light-emitting element, and the blue light emission from the blue light-emitting element, the display device 10 can be used for a full-color display. Furthermore, the display device 10 can also be used for a full-color display by placing a white light-emitting element, as the light-emitting element 200, in each pixel and extracting red light, green light, and blue light emission from the white light emitted by the white light-emitting element via a color filter.Furthermore, the display device 10 for a full color display is also possible by arranging an ultraviolet light emitting element as the light emitting element 200 in each pixel, converting ultraviolet light from the ultraviolet light emitting element via a red phosphor, a green phosphor and a blue phosphor and extracting red light emission, green light emission and blue light emission.

[0032] In the display device 10, the multiple light-emitting elements 200 can be arranged in a matrix or can be arranged in a zigzag or striped pattern.

[0033] The structure of the light-emitting element 200 is not limited to a vertical electrode structure, in which the electrodes are arranged vertically. A horizontal electrode structure, in which the electrodes are arranged horizontally, is also possible for the light-emitting element 200. The in Fig. 1 The light-emitting element 200 shown has the vertical electrode structure, one of the electrodes of the light-emitting element 200 is electrically connected to the metal layer 190, and the other of the electrodes of the light-emitting element 200 is electrically connected to the second connecting electrode 210.

[0034] The light-emitting element 200 is provided above the metal layer 190, and the metal layer 190 and the light-emitting element 200 are bonded and electrically connected to each other by a solder such as tin (Sn) or an alloy containing tin, a silver (Ag) paste, or a conductive material such as ACF.

[0035] The second connecting electrode 210 can transmit light emitted by the light-emitting element 200. Furthermore, the second connecting electrode 210 preferably has high conductivity. For example, a transparent conductive oxide such as indium tin oxide (ITO) or indium zinc oxide (IZO) can be used as the material for the second connecting electrode 210.

[0036] Next, an effect of the metal layer 190 provided on the convex section 171 will be described with reference to Fig. 2 described.

[0037] Fig. 2A and Fig. Figures 2B are a schematic, partially enlarged view and a schematic top view of the display device 10 according to the embodiment of the present invention. In particular, Fig. 2A an enlarged cross-sectional view of an area 11, which is located in Fig. is surrounded by the dashed line shown in point 1. Furthermore, Fig. 2B a top view corresponding to area 11 of Fig. 2A corresponds to. Fig. 2A and Fig. For the sake of simplicity, the second connecting electrode 210 on the light-emitting element 200 (2B) has been omitted.

[0038] As in Fig. As shown in Figure 2A, the metal layer 190 provided on the convex section 171 covers not only the upper surface of the convex section 171, but also the side surface of the convex section 171. That is, since the metal layer 190 is provided along the side surface of the convex section 171, the metal layer 190 includes a step 191.

[0039] Furthermore, as in Fig. 2B shows the stage 191 of the metal layer 190 being designed to surround the light-emitting element 200.

[0040] As described above, the metal layer 190 and the light-emitting element 200 are joined by a material such as solder, silver paste, or ACF, and a heat treatment is performed at the time of joining. Since the material of the organic insulating layer 170 and the material of the metal layer 190 generally have different coefficients of thermal expansion, the stress generated during expansion or contraction due to the heat treatment differs between the organic insulating layer 170 and the metal layer 190. Therefore, if the stress difference between the organic insulating layer 170 and the metal layer 190 is large, peeling occurs at the interface between the organic insulating layer 170 and the metal layer 190.

[0041] In the present embodiment, however, the metal layer 190 incorporates the step 191. By including the step 191 in the metal layer 190, the stress on the metal layer 190 includes not only the horizontal component but also the vertical component, and the stress on the metal layer 190 is distributed. In other words, the stress on the metal layer 190 can be said to be reduced by including the step 191 in the metal layer 190. Since the stress on the metal layer 190 is reduced not only by the heat treatment during the bonding of the light-emitting element 200 but also by the thermal changes in the operating environment of the display device 10, the reliability of the display device 10 is improved.

[0042] As described above, in the display device 10 of the present embodiment, the metal layer 190 incorporates the step 191 due to the convex section 171 provided on the organic insulating layer 170. Therefore, during the heat treatment for bonding the light-emitting element 200, the stress in the metal layer 190 is relieved, thus preventing delamination at the interface between the metal layer 190 and the organic insulating layer 170. Furthermore, since the display device 10 is resistant to thermal changes, its reliability is improved.

[0043] The display device 10 can be modified or redesigned in various ways. Therefore, a display device 10A and a display device 10B, which are modifications of the display device 10, are described with reference to sections 1 and 2, 3 and 4. Furthermore, a modification of the display device 10 is not limited to the following modification. [Modification 1]

[0044] Fig. Figure 3 is a schematic, partially enlarged view of the display device 10A according to the embodiment of the present invention. In particular, Fig. 3 a partially enlarged view of an area 11A of the display device 10A corresponding to the area 11, which is defined by the in Fig. The area is surrounded by the dashed line shown in section 1.

[0045] As in Fig. As shown in Figure 3, the indicator device 10A comprises an organic insulating layer 170A, a metal layer 190A, and a light-emitting element 200. The organic insulating layer 170A has a recessed section 171A, which is recessed from an upper surface of the organic insulating layer 170A. The metal layer 190A is designed to cover the recessed section 171A. The light-emitting element 200 is connected to the metal layer 190A by a conductive material, such as solder, silver paste, or ACF.

[0046] The depth of the recessed section 171A (the distance from the upper surface of the organic insulating layer 170A to the lower surface of the recessed section 171A) is, for example, greater than or equal to 0.2 µm and less than or equal to 10 µm. Furthermore, the depth of the recessed section 171A is preferably greater than or equal to 1 / 2 the thickness of the metal layer 190, and more preferably a depth greater than the thickness of the metal layer 190. Additionally, one side face of the recessed section 171A may be tapered. That is, the side face of the recessed section 171A need not be perpendicular to the upper surface of the organic insulating layer 170A.The angle formed by the upper surface of the organic insulating layer 170A and the side surface of the recessed section 171A is, for example, greater than or equal to 20 degrees and less than or equal to 90 degrees, preferably greater than or equal to 30 degrees and less than or equal to 80 degrees, and more preferably greater than or equal to 40 degrees and less than or equal to 70 degrees.

[0047] Furthermore, the shape of the recessed section 171A can be circular, elliptical, or polygonal in a top view. It is preferred that the shape of the recessed section 171A corresponds to the shape of the light-emitting element 200. For example, if the shape of the light-emitting element 200 is rectangular, it is preferred that the shape of the recessed section 171A is also rectangular.

[0048] As in Fig. As shown in Figure 3, the metal layer 190A provided on the recessed section 171A covers not only the upper surface of the recessed section 171A, but also the side surface of the recessed section 171A. That is, since the metal layer 190A is provided along the side surface of the recessed section 171A, the metal layer 190A contains a step 191A. Because the metal layer 190A contains the step 191A, the stress in the metal layer 190 is also reduced during the heat treatment in the display device 10A at the time of bonding the light-emitting element 200.

[0049] As described above, in the indicator device 10A of the present embodiment, the metal layer 190A includes the step 191A due to the recessed section 171A provided on the organic insulating layer 170A. Therefore, during the heat treatment for bonding the light-emitting element 200, the stress on the metal layer 190A is relieved, thus preventing delamination at the interface between the metal layer 190A and the organic insulating layer 170A. Furthermore, since the indicator device 10A is resistant to thermal changes, its reliability is improved. [Modification 2]

[0050] Fig. Figure 4 is a schematic, partially enlarged view of the display device 10B according to the embodiment of the present invention. In particular, Fig. 4 a partially enlarged view of an area 11B of the display device 10B corresponding to the area 11, which is defined by the in Fig. The area is surrounded by the dashed line shown in section 1.

[0051] As in Fig. As shown in Figure 4, the indicator device 10B comprises an organic insulating layer 170B, an inorganic insulating layer 172B, a metal layer 190B, and a light-emitting element 200. The inorganic insulating layer 172B has a predetermined pattern and is provided on the organic insulating layer 170B. The metal layer 190B is provided to cover the inorganic insulating layer 172B. The light-emitting element 200 is connected to the metal layer 190B by a conductive material such as solder, silver paste, or ACF.

[0052] The thickness of the inorganic insulating layer 172b is, for example, greater than or equal to 0.2 nm and less than or equal to 10 nm, preferably greater than or equal to 1 / 2 the thickness of the metal layer 190 and more preferably a thickness greater than the thickness of the metal layer 190.

[0053] One side face of the inorganic insulating layer 172B may be tapered. That is, the side face of the inorganic insulating layer 172B need not be perpendicular to a top face of the organic insulating layer 170B. The angle formed by the top face of the organic insulating layer 170B and the side face of the inorganic insulating layer 172B is, for example, greater than or equal to 20 degrees and less than or equal to 90 degrees, preferably greater than or equal to 30 degrees and less than or equal to 80 degrees, and more preferably greater than or equal to 40 degrees and less than or equal to 70 degrees.

[0054] For the inorganic insulating layer 172B, an insulating material can be used. For example, the insulating material could be an inorganic insulating material such as silicon dioxide (SiO₂). x ), silicon oxynitride (SiO₂) x N y ), silicon nitride (SiN x ), silicon nitride oxide (SiN x O y ), aluminum oxide (AlO x ), Aluminum oxynitride (AlO x N y ), aluminum nitride oxide (AlN x O y ), Aluminum nitride (AlN x ) or the like, the insulating material is not limited to these. Here, SiO₂ is used. x N y and AlO x N y Silicon compounds and aluminum compounds containing nitrogen in a smaller amount than oxygen. Furthermore, SiN x O y and AlN x O ySilicon compounds and aluminum compounds containing oxygen in a lower quantity than nitrogen. Furthermore, the inorganic insulating layer 172b can be stacked with these materials.

[0055] Furthermore, the inorganic insulating layer 172B has a predetermined pattern in a top view, and the shape of the pattern can be circular, elliptical, or polygonal. Preferably, the shape of the pattern of the inorganic insulating layer 172B corresponds to the shape of the light-emitting element 200. For example, if the shape of the light-emitting element 200 is rectangular, it is preferred that the shape of the inorganic insulating layer 172B is also rectangular.

[0056] As in Fig. As shown in Figure 4, the metal layer 190B provided on the inorganic insulating layer 172B covers not only the upper surface of the inorganic insulating layer 172B, but also the side surface of the inorganic insulating layer 172B. That is, since the metal layer 190B is provided along the side surface of the inorganic insulating layer 172B, the metal layer 190B contains a step 191B. Since the metal layer 190B contains the step 191B, the stress in the metal layer 190B is also reduced during heat treatment in the display device 10B at the time of bonding the light-emitting element 200.

[0057] As described above, in the display device 10B of the present embodiment, the metal layer 190B contains the step 191B due to the inorganic insulating layer 172B, which is provided on the organic insulating layer 170B. Therefore, during the heat treatment for bonding the light-emitting element 200, the stress in the metal layer 190B is relieved, so that delamination at the interface between the metal layer 190B and the organic insulating layer 170B can be suppressed. Furthermore, since the display device 10B is resistant to thermal changes, its reliability is improved. < Second embodiment>

[0058] A display device 20 according to an embodiment of the present invention is described with reference to Fig. 5 described.

[0059] Fig. Figure 5 is a schematic top view of the display device 20 according to the embodiment of the present invention. In particular, Fig. 5 a top view in an area 11C which includes two adjacent light-emitting elements 200.

[0060] As in Fig. As shown in Figure 5, the display device 20 comprises an organic insulating layer 170C, a first metal layer 190C-1, a second metal layer 190C-2, a first light-emitting element 200-1, and a second light-emitting element 200-2. A convex section 171C is provided on an upper surface of the organic insulating layer 170C and extends such that it overlaps the two light-emitting elements 200. In other words, the convex section 171C is provided in a striped pattern. The first metal layer 190C-1 and the second metal layer 190C-2 are provided such that they cover the convex section 171C. The first light-emitting element 200-1 is connected to the first metal layer 190C-1 and the second light-emitting element 200-2 is connected to the second metal layer 190C-2 by a conductive material such as solder, silver paste or ACF.

[0061] Although in Fig. Since the convex section 171C extends in only one direction, it can be extended in two directions. In other words, the convex section can be positioned so that the two straight lines intersect in a top view. In this case, the light-emitting element 200 is located at the intersection of the two straight lines.

[0062] As in Fig. As shown in Figure 5, the first metal layer 190C-1 and the second metal layer 190C-2 provided on the convex section 171C cover not only a top surface of the convex section 171C, but also a side surface of the convex section 171C. That is, since the first metal layer 190C-1 and the second metal layer 190C-2 are provided along the side surface of the convex section 171C, the first metal layer 190C-1 and the second metal layer 190C-2 include a first stage 191C-1 and a second stage 191C-2, respectively. Since the first metal layer 190C-1 and the second metal layer 190C-2 contain the first stage 191C-1 and the second stage 191C-2 respectively, the stresses of the first metal layer 190C-1 and the second metal layer 190C-2 also occur in the display device 20 and are relieved during the heat treatment at the time of bonding the light-emitting element 200.

[0063] As described above, in the indicator device 20 of the present embodiment, the first metal layer 190C-1 and the second metal layer 190C-2, due to their convexity, contain the first stage 191C-1 and the second stage 191C-2, respectively, section 171C, which is provided and extended on the organic insulating layer 170C. Therefore, during the heat treatment for bonding the light-emitting element 200, the stress on the first metal layer 190C-1 and the second metal layer 190C-2 is relieved, thus preventing delamination at the interface between the first metal layer 190C-1 and the organic insulating layer 170C-1 or the second insulating layer 170C-2. Furthermore, since the indicator device 20 is resistant to thermal changes, its reliability is improved. < Third embodiment >

[0064] A method for manufacturing the display device 10 according to an embodiment of the present invention is described with reference to Fig. 6 described.

[0065] Fig. Figures 6A to 6C are schematic, partially enlarged views of the display device 10 in the method for manufacturing the display device 10 according to the embodiment of the present invention. In particular Fig. Figures 6A to 6C are partially enlarged views of area 11, which is surrounded by the dashed line shown in Fig. 1 is shown in each step of the manufacturing process. In the Fig. In 6A to 6C, the layer beneath the organic insulating layer 170 is omitted. The layer beneath the organic insulating layer 170 can be produced using a standard procedure.

[0066] First, the organic insulating layer 170 is formed. The organic insulating layer 170 can be formed by spin coating, slot coating, printing, inkjet printing, or the like. Next, a photoresist 300 is applied to the organic insulating layer 170, exposure is carried out using the photoresist 300 as a mask, and the organic insulating layer 170 is semi-etched ( Fig. 6A). Alternatively, the photoresist 300 can be exposed as a halftone mask on the organic insulating layer 170 to etch the organic insulating layer 170. The photoresist 300 is removed by the removal solution. The above procedure forms the convex section 171 on the upper surface of the organic insulating layer 170.

[0067] Next, the metal layer 190 is formed. The metal layer 190 can be formed by sputtering, CVD, or the like. Next, the photoresist 310 is applied to the metal layer 190, exposure is carried out using the photoresist 310 as a mask, and the metal layer 190 is etched ( Fig. 6B). The photoresist 310 is removed by the removal solution. By the above procedure, a step 191 is formed on the metal layer 190, which covers the convex section 171.

[0068] Next, a bonding material 230, such as solder, silver paste or ACF, is applied to the metal layer 190, and the light-emitting element 200 is bonded ( Fig. 6C). In addition, heat treatment can be carried out when the light-emitting element 200 is bonded.

[0069] As described above, according to the manufacturing process of the indicator device 10 of the present embodiment, the metal layer 190 contains the step 191 due to the convex section 171 provided on the organic insulating layer 170. Therefore, during the heat treatment for bonding the light-emitting element 200, the stress in the metal layer 190 is relieved, thus suppressing delamination at the interface between the metal layer 190 and the organic insulating layer 170. Since the temperature of the heat treatment can be increased, the bond strength between the metal layer 190 and the light-emitting element 200 can be improved. Furthermore, since the indicator device 10 is resistant to thermal changes, its reliability is enhanced.

[0070] Other effects that differ from those produced by each of the embodiments described above, but which are evident from the description herein or which can be easily predicted by those skilled in the art, shall of course be understood as being produced by the present invention. [Explanation of reference symbols]

[0071] 10, 10A, 10B, 20: Display device, 11, 11A, 11B, 11C: Area, 100: Substrate, 110: First wiring layer, 120: Second wiring layer, 130: First insulating layer, 140: Second conductive layer, 150: Second insulating layer, 160: First conductive layer, 170: Organic insulating layer, 170A, 170B, 170C: Organic layer, 171: Convex section, 171A: Recessed section, 171C: Convex section, 172B: Inorganic insulating layer, 180: First connecting electrode, 190, 190A, 190B: Metal layer, 190C-1: First metal layer, 190C-2: Second metal layer, 191, 191A, 191B: Step, 191C-1: First step, 191C-2: Second step, 200: Light-emitting layer, 200-1: First light-emitting layer, 200-2: Second light-emitting layer, 210: Second connecting electrode, 230: Connecting material, 250: Leveling layer, 300, 310: Photoresist

Claims

Display device (10B) comprising: a substrate (100); an organic insulating layer (170B) over the substrate (100); an inorganic insulating layer (172B) with a predetermined pattern over the organic insulating layer (170B); a metal layer (190B) over the inorganic insulating layer (172B); and a light-emitting element (200) over the metal layer (190B), wherein the inorganic insulating layer (172B) overlaps the light-emitting element (200) and the metal layer (190B) covers the inorganic insulating layer (172B) and comprises a step section along a side face of the inorganic insulating layer (172B). Display device (10B) according to claim 1, wherein the thickness of the inorganic insulating layer (172B) is greater than or equal to 0.2 µm and less than or equal to 10 µm. Display device (10B) according to claim 1, wherein the side surface of the inorganic insulating layer (172B) has a taper and an angle formed by an upper surface of the organic insulating layer (170B) and the side surface of the inorganic insulating layer (172B) is greater than or equal to 20 degrees and less than or equal to 90 degrees. Display device (10B) according to claim 1, wherein one form of the predetermined pattern in a top view is circular, elliptical or polygonal. Display device (10B) according to claim 1, wherein the display device (10B) comprises several light-emitting elements (200) and the inorganic insulating layer (172B) extends such that it overlaps at least two of the light-emitting elements (200). Display device (10B) according to claim 1, wherein the light-emitting element (200) is a micro-LED.

Images