Display device and repair method of display device

Abstract

To provide a display device making it possible to replace an LED chip with another even in a case where a defective pixel arises, and a repair method of a display device capable of replacing an LED chip of a defective pixel with another.SOLUTION: A display device includes a first LED chip disposed at a pixel, a first mounting pad disposed at the pixel and connected to the first LED chip, a second mounting pad disposed at the pixel and electrically connected to the first mounting pad while being superposed on the first mounting pad in a plan view, and an insulating layer between the first mounting pad and second mounting pad.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] One embodiment of the present invention relates to a display device and a method for repairing the display device, and more particularly to a display device on which an LED (Light Emitting Diode) chip is mounted and a method for repairing the display device. [Background technology]

[0002] In recent years, LED displays, in which tiny LED chips are mounted in each pixel, have been developed as the next generation of display devices. LED displays have a structure in which multiple LED chips are mounted on a circuit board that forms a pixel array. The circuit board has drive circuits for emitting light from the LEDs at positions corresponding to each pixel. These drive circuits are electrically connected to each LED chip.

[0003] There are various methods for mounting multiple LED chips on a circuit board. For example, a method is known in which LED chips mounted on a support substrate are attached to the circuit board, and then only the support substrate is removed. For example, Patent Document 1 describes a technology in which a light-shielding mask is used to selectively irradiate LED chips with laser light at high throughput. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-005830 Summary of the Invention [Problem to be solved by the invention]

[0005] In display devices that incorporate LED chips, a major issue is the yield when mounting the LED chips from the support substrate to the circuit board. For example, poor connection between the LED chip and the circuit board can occur. Such poor connection can cause defects in the pixels. To repair such defects, a redundant design can be considered, providing spare mounting pads for the pixels.

[0006] However, providing spare LED chip mounting pads within a pixel increases the area per pixel, making it difficult to miniaturize pixels and making it impossible to accommodate higher resolution.

[0007] An object of one embodiment of the present invention is to provide a display device in which an LED chip can be replaced even if a defective pixel occurs.An object of one embodiment of the present invention is to provide a display device repair method in which an LED chip of a defective pixel can be replaced. [Means for solving the problem]

[0008] One embodiment of the present invention is a display device that includes a first LED chip disposed in a pixel, a first mounting pad disposed in the pixel and connected to the first LED chip, a second mounting pad disposed in the pixel and overlapping and electrically connected to the first mounting pad in a plan view, and an insulating layer between the first mounting pad and the second mounting pad.

[0009] One embodiment of the present invention is a method for repairing a display device, which includes irradiating a first LED chip disposed in a pixel and determined to be defective with a first laser beam to remove the first LED chip, irradiating a first mounting pad disposed in the pixel and connected to the first LED chip with a second laser beam to remove the first mounting pad, irradiating an insulating layer overlapping the first mounting pad with a third laser beam to remove the insulating layer, thereby exposing a second mounting pad overlapping the first mounting pad in a planar view, and mounting a second LED chip on the second mounting pad. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a plan view showing a schematic configuration of a display device according to an embodiment of the present invention; [Figure 2] 1 is a block diagram showing a circuit configuration of a display device according to an embodiment of the present invention. [Figure 3] 1 is an example of a circuit diagram showing a configuration of a pixel circuit of a display device according to an embodiment of the present invention. [Figure 4] 1 is a plan view showing a configuration of a pixel of a display device according to an embodiment of the present invention. [Figure 5] 1 is a cross-sectional view showing a configuration of a pixel of a display device according to one embodiment of the present invention. [Figure 6] 1 is a plan view showing a configuration of a pixel of a display device according to an embodiment of the present invention. [Figure 7] 1 is a cross-sectional view showing a configuration of a pixel of a display device according to one embodiment of the present invention. [Figure 8] FIG. 1 is a flowchart illustrating a method for repairing a display device according to an embodiment of the present invention. [Figure 9] 1A to 1C are cross-sectional views illustrating a method for repairing a display device according to an embodiment of the present invention. [Figure 10] 1A to 1C are cross-sectional views illustrating a method for repairing a display device according to an embodiment of the present invention. [Figure 11] 1A to 1C are cross-sectional views illustrating a method for repairing a display device according to an embodiment of the present invention. [Figure 12] 1A to 1C are cross-sectional views illustrating a method for repairing a display device according to an embodiment of the present invention. [Figure 13] 1A to 1C are cross-sectional views illustrating a method for repairing a display device according to an embodiment of the present invention. [Figure 14] FIG. 10 is a plan view showing the configuration of a pixel after repair of a display device according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention can be implemented in various forms without departing from the spirit of the present invention. The present invention should not be interpreted as being limited to the description of the embodiments exemplified below. In order to clarify the explanation, the drawings may show the width, thickness, shape, etc. of each part more schematically than the actual form. However, the drawings are merely examples and do not limit the interpretation of the present invention.

[0012] When describing embodiments of the present invention, the direction from the substrate toward the LED chip is referred to as "upper," and the opposite direction is referred to as "lower." However, the terms "upper" and "lower" merely describe the upper-level relationship of each element. For example, the term "LED chip is disposed on a substrate" also includes cases where other components are interposed between the substrate and the LED chip. Furthermore, the terms "upper" and "lower" include not only cases where elements overlap in a plan view, but also cases where they do not overlap.

[0013] When describing embodiments of the present invention, elements having the same functions as elements already described may be designated by the same reference numeral or by the same reference numeral with an alphabet or other symbol, and the description thereof may be omitted. Furthermore, when it is necessary to describe a certain element separately for each of the RGB colors, the reference numeral for that element is followed by an R, G, or B symbol to distinguish between them. However, when it is not necessary to describe a certain element separately for each of the RGB colors, the element will be described using only the reference numeral for that element.

[0014] First Embodiment In this embodiment, a display device 10, which is one embodiment of the present invention, will be described.

[0015] (Display device configuration) Fig. 1 is a plan view showing a schematic configuration of a display device 10 according to one embodiment of the present invention. As shown in Fig. 1, the display device 10 has a circuit board 100, a flexible printed circuit board 160 (FPC 160), and an IC chip 170. The display device 10 has a display area 112, a peripheral area 114, and a terminal area 116.

[0016] The display area 112 is an area in which a plurality of pixels 110, each including an LED chip 202, are arranged in the row direction (D1 direction) and column direction (D2 direction). Specifically, in this embodiment, a pixel 110R including a red LED chip 202R, a pixel 110G including a green LED chip 202G, and a pixel 110B including a blue LED chip 202B are arranged. FIG. 1 shows an example in which the pixel 110R, pixel 110G, and pixel 110B are treated as sub-pixels and form one pixel 110. The display area 112 functions as an area for displaying an image in accordance with a video signal.

[0017] The peripheral region 114 is a region surrounding the display region 112. The peripheral region 114 is a region where driver circuits (data driver circuit 130 and gate driver circuit 140 shown in FIG. 2) for controlling pixel circuits (pixel circuits 120 shown in FIG. 2) provided in each pixel 110 are provided.

[0018] The terminal area 116 is an area where multiple wirings connected to the driver circuit described above are aggregated. The flexible printed circuit board 160 is electrically connected to the multiple wirings in the terminal area 116. A video signal (data signal) or a control signal output from an external device (not shown) is input to the IC chip 170 via wirings (not shown) provided on the flexible printed circuit board 160. The IC chip 170 performs various signal processing on the video signal and generates control signals required for display control. The video signal and control signal output from the IC chip 170 are input to the display device 10 via the flexible printed circuit board 160.

[0019] (Circuit configuration of display device 10) Fig. 2 is a block diagram showing the circuit configuration of a display device 10 according to one embodiment of the present invention. As shown in Fig. 2, a pixel circuit 120 is provided in a display region 112 corresponding to each pixel 110. In this embodiment, a pixel circuit 120R, a pixel circuit 120G, and a pixel circuit 120B are provided in correspondence with pixels 110R, 110G, and 110B, respectively. That is, a plurality of pixel circuits 120 are arranged in the row direction (direction D1) and the column direction (direction D2) in the display region 112.

[0020] 3 is a circuit diagram showing the configuration of a pixel circuit 120 of a display device 10 according to one embodiment of the present invention. The pixel circuit 120 is disposed in an area surrounded by a data line 121, a gate line 122, an anode power line 123, and a cathode power line 124. The pixel circuit 120 of this embodiment includes a selection transistor 126, a drive transistor 127, a storage capacitor 128, and an LED 129. The LED 129 corresponds to the LED chip 202 shown in FIG. 1. The circuit elements of the pixel circuit 120 other than the LED 129 correspond to the drive circuit 102 provided on the circuit board 100. In other words, the pixel circuit 120 is completed when the LED chip 202 is mounted on the circuit board 100.

[0021] 3, the source electrode, gate electrode, and drain electrode of the selection transistor 126 are connected to the data line 121, gate line 122, and gate electrode of the drive transistor 127, respectively. The source electrode, gate electrode, and drain electrode of the drive transistor 127 are connected to the anode power supply line 123, the drain electrode of the selection transistor 126, and the LED 129, respectively. A storage capacitor 128 is connected between the gate electrode and source electrode of the drive transistor 127. That is, the storage capacitor 128 is connected to the drain electrode of the selection transistor 126. The anode and cathode of the LED 129 are connected to the drain electrode of the drive transistor 127 and the cathode power supply line 124, respectively.

[0022] A grayscale signal that determines the light emission intensity of the LED 129 is supplied to the data line 121. A gate signal that selects a selection transistor 126 to which the grayscale signal is written is supplied to the gate line 122. When the selection transistor 126 is turned on, the grayscale signal is stored in a storage capacitor 128. After that, when the drive transistor 127 is turned on, a drive current corresponding to the grayscale signal flows through the drive transistor 127. When the drive current output from the drive transistor 127 is input to the LED 129, the LED 129 emits light at a light emission intensity corresponding to the grayscale signal.

[0023] 2 again, a data driver circuit 130 is disposed adjacent to the display area 112 in the column direction (direction D2). A gate driver circuit 140 is disposed adjacent to the display area 112 in the row direction (direction D1). In this embodiment, two gate driver circuits 140 are provided on both sides of the display area 112, but only one of them may be provided.

[0024] The data driver circuit 130 and the gate driver circuit 140 are both arranged in the peripheral region 114. However, the region in which the data driver circuit 130 is arranged is not limited to the peripheral region 114. For example, the data driver circuit 130 may be arranged on a flexible printed circuit board 160.

[0025] 3 extends in the direction D2 from the data driver circuit 130 and is connected to the source electrode of the selection transistor 126 in each pixel circuit 120. The gate line 122 extends in the direction D1 from the gate driver circuit 140 and is connected to the gate electrode of the selection transistor 126 in each pixel circuit 120.

[0026] A terminal section 150 is arranged in the terminal region 116. The terminal section 150 is connected to the data driver circuit 130 via a connection wiring 151. Similarly, the terminal section 150 is connected to the gate driver circuit 140 via a connection wiring 152. Furthermore, the terminal section 150 is connected to a flexible printed circuit board 160.

[0027] (Structure of pixel 110) 4 is a plan view showing the configuration of a pixel of a display device according to one embodiment of the present invention. The pixel 110 includes an LED chip 202, a first mounting pad 25a-1, a second mounting pad 25a-2, and a conductive layer 30. As shown in FIG. 4, the pixel 110 may include regions for arranging a red LED chip 202R, a green LED chip 202G, and a blue LED chip 202B.

[0028] The mounting pad in this embodiment is an area formed of a metal film for mounting the LED chip on the substrate, and is an electrode. The shape of the mounting pad in plan view is arbitrary, and it can be designed appropriately to suit the electrode shape and electrode arrangement of the LED chip.

[0029] In a plan view, the LED chip 202 overlaps the first mounting pad 25a-1, the second mounting pad 25a-2, and the conductive layer 30. In a plan view, the area of ​​the LED chip 202 is smaller than the areas of the first mounting pad 25a-1, the second mounting pad 25a-2, and the conductive layer 30. By reducing the area of ​​the LED chip 202, it is possible to apply a voltage to the entire LED chip 202.

[0030] The first mounting pad 25a-1 can have an area that overlaps with the LED chip 202 and the second mounting pad 25a-2, and an area that does not overlap with the LED chip 202.

[0031] As will be described in detail below, a new LED chip 402 (not shown) can be mounted in the area overlapping with the LED chip 202 and second mounting pad 25a-2, replacing the currently mounted LED chip 202. When mounting the new LED chip 402, the first mounting pad 25a-1 disposed in the area overlapping with the LED chip 202 and second mounting pad 25a-2 is removed.

[0032] In the region where the first mounting pad 25a-1 and the LED chip 202 do not overlap, the first mounting pad 25a-1 can be directly or electrically connected to the second mounting pad 25a-2. As shown in Fig. 4, the first mounting pad 25a-1 is connected to the second mounting pad 25a-2 via a contact hole 262 arranged in the region where the first mounting pad 25a-1 and the second mounting pad 25a-2 overlap. By connecting the first mounting pad 25a-1 and the second mounting pad 25a-2, the same potential can be applied to the first mounting pad 25a-1 and the second mounting pad 25a-2.

[0033] The first mounting pad 25a-1 can be formed to surround the LED chip 202. As shown in Fig. 4, the first mounting pad 25a-1 can have a portion surrounding the LED chip 202 and a portion extending from the portion surrounding the LED chip 202 toward the outer edge 110e of the pixel 110. Here, the portion surrounding the LED chip 202 corresponds to the region of the first mounting pad 25a-1 that overlaps with the LED chip 202 and the second mounting pad 25a-2, and the portion extending from the portion surrounding the LED chip 202 toward the outer edge 110e of the pixel 110 corresponds to the region of the first mounting pad 25a-1 that does not overlap with the LED chip 202.

[0034] The area of ​​the first mounting pad 25a-1 may be smaller than the area of ​​the second mounting pad 25a-2. Because the area of ​​the first mounting pad 25a-1 is small, when the pixel 110 is provided with a plurality of red LED chips 202R, green LED chips 202G, and blue LED chips 202B, as shown in FIG. 4, the distance between the first mounting pads 25a-1 connected to each of the plurality of LED chips 202 is increased, making it easy to remove the first mounting pad 25a-1 connected to one of the plurality of LED chips 202. However, depending on the arrangement of the plurality of LED chips 202 in the pixel 110, the area of ​​the first mounting pad 25a-1 may be larger than the area of ​​the second mounting pad 25a-2.

[0035] The second mounting pad 25a-2 can be formed to surround the LED chip 202 and the first mounting pad 25a-1. As shown in Fig. 4, the second mounting pad 25a-2 can have a portion surrounding the LED chip 202 and a portion extending from the portion surrounding the LED chip 202 toward the outer edge 110e of the pixel 110. The portion surrounding the LED chip 202 corresponds to the repair region RP, and the portion surrounding the LED chip 202 and the portion extending from the portion surrounding the LED chip 202 toward the outer edge 110e of the pixel 110 correspond to the region OT.

[0036] The repair area RP is an area where, if the currently mounted LED chip 202 is determined to be defective, a new LED chip 302 is mounted in place of the LED chip 202. The area OT is an area where a portion to be connected to the first mounting pad 25a-1 is located.

[0037] The first mounting pad 25a-1 and the second mounting pad 25a-2 are arranged at a distance from adjacent first mounting pads 25a-1 and second mounting pads 25a-2. When multiple LED chips 202 are arranged in the pixel 110, the first mounting pads 25a-1 and second mounting pads 25a-2 connected to each of the multiple LED chips 202 are arranged at a distance from each other. As shown in Fig. 4, the first mounting pad 25a-1 and second mounting pad 25a-2 overlapping and electrically connecting with the red LED chip 202R are arranged at a distance from the first mounting pad 25a-1 and second mounting pad 25a-2 overlapping and electrically connecting with the adjacent green LED chip 202G.

[0038] The conductive layer 30 can be electrically connected to the LED chip 202. The conductive layer 30 is disposed overlapping the LED chip 202, the first mounting pad 25a-1, and the second mounting pad 25a-2. The conductive layer 30 can be formed to surround the LED chip 202. As shown in FIG. 4, the conductive layer 30 can have a portion surrounding the LED chip 202 and a portion extending from the portion surrounding the LED chip 202 toward the outer edge 110e of the pixel 110. When multiple LED chips 202 are provided in the pixel 110, the portion of the conductive layer 30 extending toward the outer edge 110e of the pixel 110 connects to conductive layers 30 electrically connected to other LED chips 202. For example, as shown in FIG. 4, the conductive layer 30 overlapping and electrically connecting with the red LED chip 202R can be connected to the conductive layer 30 overlapping and electrically connecting with the green LED chip 202G at the portion extending toward the outer edge 110e of the pixel 110. In this way, the conductive layers 30 electrically connected to the multiple LED chips 202 in the same pixel 110 are connected to each other, so that the same potential can be applied to these conductive layers 30 .

[0039] Fig. 5 is a cross-sectional view showing the configuration of a pixel of a display device according to one embodiment of the present invention. Specifically, Fig. 5 is a cross-sectional view taken along line A1-A2 in Fig. 4. In Fig. 5, the same components as those of pixel 110 shown in Fig. 4 are assigned the same reference numerals, and redundant explanations will be omitted.

[0040] The pixel 110 has a drive transistor 127 provided on an insulating substrate 11. The insulating substrate 11 can be a transparent substrate in which an insulating layer is provided on a glass substrate or a resin substrate.

[0041] The driving transistor 127 includes a semiconductor layer 12, a gate insulating layer 13, and a gate electrode 14. A source electrode 16 and a drain electrode 17 are connected to the semiconductor layer 12 via an insulating layer 15. Although not shown, the gate electrode 14 is connected to the drain electrode of the selection transistor 126 shown in FIG.

[0042] Wiring 18 is provided on the same layer as the source electrode 16 and the drain electrode 17. Wiring 18 functions as the anode power line 123 shown in FIG. 3. Therefore, the source electrode 16 and wiring 18 are electrically connected by a connection wiring 20 provided on a planarization layer 19. The planarization layer 19 is a transparent resin layer made of a resin material such as polyimide or acrylic. The connection wiring 20 is a transparent conductive layer made of a metal oxide material such as ITO. However, this is not limiting, and other metal materials can also be used for the connection wiring 20.

[0043] An insulating layer 21 made of silicon nitride or the like is provided on the connection wiring 20. A conductive layer 22 and a conductive layer 23 are provided on the insulating layer 21. In this embodiment, the conductive layer 22 and the conductive layer 23 are electrodes made of a light-shielding metal material. The conductive layer 22 is connected to the drain electrode 17 via a contact hole (opening) provided in the planarization layer 19 and the insulating layer 21.

[0044] A planarizing layer 24 is provided on the conductive layer 22 and the conductive layer 23. The planarizing layer 24 is a transparent resin layer made of a resin material such as polyimide or acrylic.

[0045] A second mounting pad 25a-2 is formed on the planarization layer 24. The second mounting pad 25a-2 is connected to the conductive layer 22 via a contact hole 264 provided in the planarization layer 24.

[0046] An insulating layer 28 is provided on the second mounting pad 25a-2. The thickness of the insulating layer 28 is 1 μm or more and 2 μm or less. The insulating layer 28 is an organic insulating layer made of a photosensitive resin material or the like. By using an organic insulating layer with a thickness of 1 μm or more and 2 μm or less as the insulating layer 28, it becomes easy to remove it using a laser or the like.

[0047] First mounting pad 25a-1 and mounting pad 25b are provided on insulating layer 28. First mounting pad 25a-1 is arranged to overlap second mounting pad 25a-2 in a cross-sectional view. Insulating layer 28 is arranged between first mounting pad 25a-1 and second mounting pad 25a-2.

[0048] The first mounting pad 25a-1 is connected to the second mounting pad 25a-2 through a contact hole 262 provided in the insulating layer 28. Connecting the first mounting pad 25a-1 and the second mounting pad 25a-2 allows them to be provided with the same potential, as described above. Since the second mounting pad 25a-2 has the same potential as the first mounting pad 25a-1 and is located within the same pixel 110, the second mounting pad 25a-2 can function as a spare mounting pad for the first mounting pad 25a-1. Furthermore, since the second mounting pad 25a-2 is located overlapping the first mounting pad 25a-1, it can be used as a spare mounting pad for the first mounting pad 25a-1 by removing the first mounting pad 25a-1.

[0049] Mounting pad 25b is connected to conductive layer 23 via contact hole 263 provided in planarization layer 24 and insulating layer 28. In FIG. 5, mounting pad 25b is connected to conductive layer 23 only via contact hole 263, but electrical connection may also be made via multiple contact holes, as in the connection between first mounting pad 25a-1 and conductive layer 22. First mounting pad 25a-1, second mounting pad 25a-2, and mounting pad 25b are made of a metal material such as aluminum, titanium, molybdenum, tantalum, or tungsten.

[0050] The LED chip 202 is provided on the first mounting pad 25a-1. The LED chip 202 is arranged so as to overlap the first mounting pad 25a-1, the second mounting pad 25a-2, and the insulating layer 28. The LED chip 202 is arranged so as not to overlap the contact hole 262 and the contact hole 264. The contact hole 262 may be arranged between the LED chip 202 and the contact hole 264. By arranging the contact hole 262 between the LED chip 202 and the contact hole 264 without overlapping the LED chip 202 with the contact hole 262 and the contact hole 264, damage to the contact hole 264 due to removal of the LED chip 202 can be prevented when a new LED chip 402 (not shown) is installed in place of the LED chip 202.

[0051] The LED chip 202 corresponds to the LED 129 in the circuit diagram shown in Fig. 3. The anode 203a of the LED chip 202 is connected to the conductive layer 22 which is connected to the drain electrode 17 of the drive transistor 127. The cathode 203b of the LED chip 202 is connected to the conductive layer 23. The conductive layer 23 is electrically connected to the cathode power supply line 124 shown in Fig. 3. Note that the arrangement of the anode 203a and the cathode 203b shown in Fig. 5 is just an example, and the arrangement of the anode 203a and the cathode 203b may be reversed.

[0052] A first connection electrode 103a is provided between the first mounting pad 25a-1 and the LED chip 202. In this embodiment, an electrode made of tin (Sn) is disposed as the first connection electrode 103a.

[0053] The first connection electrode 103a is bonded to the anode 203a of the LED chip 202. The anode 203a is provided on one surface of the LED chip 202. Meanwhile, the cathode 203b is electrically connected to the conductive layer 30 provided on the other surface of the LED chip 202a. The conductive layer 30 functions as a connection electrode of the LED chip 202 and is electrically connected to the conductive layer 23. In this embodiment, the anode 203a and the cathode 203b may be electrodes made of gold (Au). The first connection electrode 103a and the anode 203a of the LED chip 202 may be bonded to each other by irradiating them with laser light and performing a heat treatment. As the laser light, laser light that is absorbed by the first connection electrode 103a or the anode 203a can be selected.

[0054] A planarization layer 26 is provided on the first mounting pad 25a-1 and the mounting pad 25b. The planarization layer 26 covers the entire side surface of the LED chip 202. The conductive layer 30 is connected to the mounting pad 25b, which is connected to the conductive layer 23, through a contact hole 261 provided in the planarization layer 26. The planarization layer 26 is a transparent resin layer made of an insulating resin material such as polyimide or acrylic.

[0055] As described above, the display device 10 according to this embodiment includes an LED chip 202 disposed in each pixel 110, a first mounting pad 25a-1 disposed in the pixel 110 and connected to the LED chip 202, a second mounting pad 25a-2 disposed in the pixel 110 and overlapping and electrically connected to the first mounting pad 25a-1 in a plan view, and an insulating layer 28 between the first mounting pad 25a-1 and the second mounting pad 25a-2. In the pixel 110 where the first mounting pad 25a-1 is disposed, the second mounting pad 25a-2 overlaps and is electrically connected to the first mounting pad 25a-1. This allows the second mounting pad 25a-2 to be provided as a spare mounting pad without requiring an additional area for the second mounting pad 25a-2 in the pixel 110. The display device 10 has a small area per pixel, allowing more pixels to be provided in the display region 112, thereby providing a high-resolution display device.

[0056] (Variation) The embodiment of the present invention described above is an LED chip with a so-called vertical structure, in which a semiconductor layer and an active layer (not shown) are sandwiched between a pair of anode 203a and cathode 203b on circuit board 100. However, the connection between the LED chip and the connection electrodes provided on insulating substrate 11 is not limited to the vertical structure.

[0057] FIG. 6 is a plan view showing the configuration of pixel 110a of display device 10 according to a modified example of one embodiment of the present invention. FIG. 7 is a cross-sectional view showing the configuration of pixel 110a of display device 10 according to a modified example of one embodiment of the present invention. As shown in FIG. 7, in pixel 110a according to the modified example, LED chip 202aR has, on one surface thereof, an anode 203a electrically connected to conductive layer 22 and a cathode 203b electrically connected to conductive layer 23, which are electrically connected to first mounting pad 25a-1 and first mounting pad 25b-1, respectively, in a so-called flip-chip mounting manner. In FIGS. 6 and 7, components identical to those of pixel 110 shown in FIGS. 4 and 5 are designated by the same reference numerals, and redundant description will be omitted.

[0058] The pixel 110a is provided with an LED chip 202a, a first mounting pad 25a-1, and a second mounting pad 25b-2. The pixel 110a can be provided with multiple LED chips 202, and multiple LED chips 202aR, 202aG, and 202aB can be arranged as shown in FIG.

[0059] In plan view, the LED chip 202a overlaps the first mounting pad 25a-1, the second mounting pad 25a-2, the first mounting pad 25b-1, and the second mounting pad 25b-2.

[0060] The first mounting pad 25a-1 overlaps the second mounting pad 25a-2 in a planar view. The first mounting pad 25b-1 overlaps the second mounting pad 25b-2 in a planar view. The first mounting pad 25b-1 can be connected to the second mounting pad 25b-2 in a region that does not overlap with the LED chip 202a. The first mounting pad 25b-1 can have a portion that extends from the portion that overlaps with the LED chip 202a toward the outer edge 110e of the pixel 110. As shown in FIG. 6, the portion of the first mounting pad 25b-1 that extends toward the outer edge 110e of the pixel 110 corresponds to the region that does not overlap with the LED chip 202a. The first mounting pad 25b-1 can be connected via a contact hole 267 arranged in the region that does not overlap with the LED chip 202a. By connecting the second mounting pad 25b-2 to the first mounting pad 25b-1, the second mounting pad 25b-2 can be given the same potential as the first mounting pad 25b-1. Since the second mounting pad 25b-2 has the same potential as the first mounting pad 25b-1 and is arranged within the same pixel 110, the second mounting pad 25b-2 can function as a spare mounting pad for the first mounting pad 25b-1. Furthermore, since the second mounting pad 25b-2 is arranged overlapping the first mounting pad 25b-1, it can be used as a spare mounting pad for the first mounting pad 25b-1 by removing the first mounting pad 25b-1.

[0061] The pixel 110a has a driving transistor 127 provided on an insulating substrate 11. The structure of the driving transistor 127 shown in FIG. 7 is the same as that of the driving transistor 127 shown in FIG. 4. A wiring 18 is provided in the same layer as the source electrode 16 and drain electrode 17 of the driving transistor 127. A planarization layer 19 is provided on the source electrode 16, the drain electrode 17, and the wiring 18. The source electrode 16 and the wiring 18 are electrically connected by a connection wiring 20 provided on the planarization layer 19.

[0062] An insulating layer 21 made of silicon nitride or the like is provided on the connection wiring 20, and a conductive layer 22 and a conductive layer 23 are provided thereon. The conductive layer 22 is connected to the drain electrode 17 via a contact hole (opening) provided in the planarizing layer 19 and the insulating layer 21.

[0063] Conductive layer 22 and conductive layer 23 are connected to second mounting pad 25a-2 and second mounting pad 25b-2, respectively, via contact holes 264 and 265 provided in planarization layer 24. Second mounting pad 25b-2 can be configured similarly to second mounting pad 25a-2.

[0064] An insulating layer 28 is provided on second mounting pad 25a-2 and second mounting pad 25b-2. First mounting pad 25a-1 and first mounting pad 25b-1 are provided on insulating layer 28. First mounting pad 25a-1 and first mounting pad 25b-1 are connected to second mounting pad 25a-2 and second mounting pad 25b-2, respectively, via contact holes 262 and contact holes 267 provided in insulating layer 28. First mounting pad 25b-1 can be configured similarly to first mounting pad 25a-1.

[0065] The first mounting pad 25a-1 electrically connected to the anode 203a and the first mounting pad 25b-1 electrically connected to the cathode 203b are provided on the insulating layer 28 and correspond to the first p-electrode pad 25a-1 and the first n-electrode pad 25b-1 corresponding to the LED chip 202a. The second mounting pad 25a-2 electrically connected to the anode 203a and the second mounting pad 25b-2 electrically connected to the cathode 203b are provided on the planarizing layer 24 and correspond to the second p-electrode pad 25a-2 and the second n-electrode pad 25b-2 corresponding to the LED chip 202a.

[0066] A first connection electrode 103a is provided between the first p-electrode pad 25a-1 and the anode 203a, and a first connection electrode 103b is provided between the first n-electrode pad 25b-1 and the cathode 203b. The first connection electrode 103b can be configured in the same way as the first connection electrode 103a.

[0067] Second Embodiment In this embodiment, a method for repairing a display device 10 including the pixel 110 described in the first embodiment will be described. Descriptions of configurations that are the same as or similar to those described in the first embodiment may be omitted.

[0068] (Display Device Repair Method) Fig. 8 is a flowchart showing a method for repairing a display device according to one embodiment of the present invention. Specifically, Fig. 8 shows a process for removing an LED chip determined to be defective from among a plurality of LED chips 202 formed on a circuit board 100 and mounting a new LED chip. Figs. 9 to 13 are cross-sectional views showing a method for repairing a display device according to one embodiment of the present invention. Figs. 9 to 13 show a simplified configuration of the pixel 110 shown in Fig. 5. Here, Fig. 8 will be used to explain the process for removing an LED chip determined to be defective from the circuit board 100 and mounting a new LED chip on the circuit board 100.

[0069] First, in step S11 of FIG. 8, the red LED chip 202R disposed in the pixel 110 and determined to be defective is removed. For example, if the red LED chip 202R shown in FIG. 4 is determined to be defective, the red LED chip 202R disposed in the pixel 110 and determined to be defective is irradiated with laser light 50E, thereby removing the red LED chip 202R from the pixel 110. As shown in FIG. 9, the red LED chip 202R determined to be defective is irradiated with laser light 50E from the direction opposite to the insulating substrate 11. By irradiating the red LED chip 202R with laser light 50E, the energy of the laser light 50E is absorbed by the red LED chip 202R, destroying and removing the red LED chip 202R. Furthermore, by irradiating the red LED chip 202R with laser light 50E, the electrode between the red LED chip 202R and the first mounting pad 25a-1 is damaged, allowing the red LED chip 202R to be removed in whole or in part. Here, Figure 9 shows an example in which laser light 50E is irradiated only onto the repair area RP, but the irradiation area of ​​laser light 50E is not limited to the repair area RP as long as adjacent structures such as LED chip 202 are not irradiated by laser light 50E.

[0070] The laser light 50E may be selected to be absorbed by the red LED chip 202R. In this embodiment, for example, ultraviolet light may be used as the laser light 50E. An excimer laser or the like may be used as the light source of the laser light 50E.

[0071] Next, in step S12 of FIG. 8, the first mounting pad 25a-1 to which the red LED chip 202R was connected is removed. For example, the first mounting pad 25a-1 to which the red LED chip 202R was connected is irradiated with laser light 50P to remove the first mounting pad 25a-1 from the pixel 110. This process exposes the insulating layer 28 that overlapped the red LED chip 202R determined to be defective. As shown in FIG. 10, the first mounting pad 25a-1 to which the red LED chip 202R was connected is irradiated with laser light 50P from the direction opposite to the insulating substrate 11. By irradiating the first mounting pad 25a-1 with laser light 50P, the energy of the laser light 50E is absorbed by the first mounting pad 25a-1, and the first mounting pad 25a-1 is sublimated and removed.

[0072] 10 shows an example in which the first mounting pad 25a-1 disposed in the contact hole 262 is not irradiated with laser light 50P in step S12, and the electrode between the red LED chip 202R and the first mounting pad 25a-1 remains partially, but the entire first mounting pad 25a-1 may be irradiated with laser light 50P to remove the first mounting pad 25a-1 so as not to interfere with the newly mounted LED 402. In this case, in step S12, the partially remaining electrode can also be removed by irradiating it with laser light 50P.

[0073] The laser light 50P may be selected to be absorbed by the first mounting pad 25a-1. In this embodiment, for example, infrared light or visible light with a wavelength centered around 800 nm may be used as the laser light 50P. An ultrashort pulse laser such as a femtosecond laser may be used as the laser light P. The laser light 50P may have a different wavelength from the laser light 50E.

[0074] 8, the insulating layer 28 overlapping the first mounting pad 25a-1 removed in step S12 is removed. For example, the insulating layer 28 overlapping the first mounting pad 25a-1 is irradiated with laser light 50C to remove the insulating layer 28. This process exposes the second mounting pad 25a-2 overlapping the first mounting pad 25a-1, as shown in FIG. 12. As shown in FIG. 11, the insulating layer 28 overlapping the first mounting pad 25a-1 is irradiated with laser light 50P from the direction opposite the insulating substrate 11. By irradiating the insulating layer 28 with laser light 50C, the energy of the laser light 50C is absorbed by the insulating layer 28, and the insulating layer 28 is removed.

[0075] The laser light 50C may be selected to be absorbed by the insulating layer 28. In this embodiment, for example, far-infrared rays may be used as the laser light 50C. A gas laser such as a carbon dioxide (CO2) laser may be used as the laser light 50C. The laser light 50C may have a wavelength different from that of the laser light 50E and the laser light 50P.

[0076] Finally, in step S14 of FIG. 8, a new LED chip 402 is mounted on the second mounting pad 25a-2 exposed in step S13. A known LED chip mounting method may be used to mount the new LED chip 402. For example, a conductive bonding layer 406 may be provided on the second mounting pad 25a-2 in advance, and the first connection electrode 303a of the new LED chip 402 may be bonded to the conductive bonding layer 406. As shown in FIG. 13, the new LED chip 402 is provided with the first connection electrode 303a, terminal electrode 403a, and terminal electrode 403b in advance, and can be electrically connected to the second mounting pad 25a-2 via the conductive bonding layer 406.

[0077] A conductive bonding material may be used for the conductive bonding layer 406. Examples of the conductive bonding material include solder such as tin (Sn) or an alloy containing tin, silver paste, and an anisotropic conductive film (ACF).

[0078] As described above, a new LED chip 402 can be mounted in the same pixel 110 as the red LED chip 202R determined to be defective on the circuit board 100. If multiple LED chips 202 are provided in the pixel 110 and one of the red LED chips 202R is determined to be defective and an LED chip 402 is mounted in place of the red LED chip 202R, the red LED chip 202R, the first mounting pad 25a-1, and the insulating layer 28 are removed in the repair region on the second mounting pad 25a-2, and the LED chip 402 is mounted on the second mounting pad 25a-2 in place of the red LED chip 202R, as shown in Fig. 14. The portion from which the insulating layer 28 has been removed is shown as region 28a.

[0079] As described above, according to the display device repair method of this embodiment, the LED chip 202 determined to be defective, the first mounting pad 25a-1 overlapping the LED chip 202, and the insulating layer 28 are removed to expose the second mounting pad 25a-2 overlapping the first mounting pad 25a-1, and a new LED chip 402 can be mounted on the second mounting pad 25a-2. By mounting the new LED chip 402 on the second mounting pad 25a-2 overlapping the first mounting pad 25a-1, the second mounting pad 25a-2 can be used as a spare mounting pad without providing an additional area for the second mounting pad 25a-2 in the pixel 110 in a plan view.

[0080] The above-described embodiments of the present invention can be combined as appropriate as long as they are not mutually inconsistent. Furthermore, even if a person skilled in the art appropriately adds or deletes components or modifies the design of a display device of each embodiment, or adds or omits processes or modifies conditions, such a display device is included in the scope of the present invention as long as it includes the gist of the present invention.

[0081] Even if there are other effects and advantages different from those brought about by the aspects of each of the above-mentioned embodiments, those that are clear from the description in this specification or that can be easily predicted by a person skilled in the art are naturally understood to be brought about by the present invention. [Explanation of symbols]

[0082] 10: display device, 11: insulating substrate, 12: semiconductor layer, 13: gate insulating layer, 14: gate electrode, 15: insulating layer, 16: source electrode, 17: drain electrode, 18: wiring, 19: planarization layer, 20: connection wiring, 21: insulating layer, 22: conductive layer, 23: conductive layer, 24: planarization layer, 25a-1: first p-electrode side pad, first mounting pad, 25a-2: second p-electrode side pad, second mounting pad, 25b: mounting pad, 25b-1: first n-electrode side pad, first mounting pad, 25b-2 : second n-electrode side pad, second mounting pad, 26: planarization layer, 28: insulating layer, 28a: region, 30: conductive layer, 50C: laser light, 50E: laser light, 50P: laser light, 100: circuit board, 102: drive circuit, 103a: first connection electrode, 104: display, 110: pixel, 110a: pixel, 110B: pixel, 110e: outer edge, 110G: pixel, 110R: pixel, 112: display region, 114: peripheral region, 116: terminal region, 120: pixel circuit, 120B: pixel circuit, 120G : pixel circuit, 120R: pixel circuit, 121: data line, 122: gate line, 123: anode power line, 124: cathode power line, 126: selection transistor, 127: drive transistor, 128: storage capacitor, 130: data driver circuit, 140: gate driver circuit, 150: terminal section, 151: connection wiring, 152: connection wiring, 160: flexible printed circuit board, 170: IC chip, 202: LED chip, 202a: LED chip, 202b: LED chip, 20 2aG: LED chip, 202aR: LED chip, 202B: blue LED chip, 202G: green LED chip, 202R: red LED chip, 203a: anode, 203b: cathode, 261: contact hole, 262: contact hole, 263: contact hole, 264: contact hole, 265: contact hole, 267: contact hole, 303a: first connection electrode, 402: LED chip, 403a: terminal electrode, 403b: terminal electrode, 406: conductive junction layer,

Claims

1. a first LED chip disposed in the pixel; a first mounting pad disposed at the pixel and connected to the first LED chip; a second mounting pad disposed at the pixel, overlapping and electrically connected to the first mounting pad in a plan view; an insulating layer between the first mounting pad and the second mounting pad; Display device.

2. The insulating layer has a thickness of 1 μm or more and 2 μm or less. The display device according to claim 1 .

3. the first mounting pad includes a first n-electrode pad corresponding to the first LED chip and a first p-electrode pad; the second mounting pad comprises, in plan view, a second n-electrode side pad overlapping the first n-electrode side pad and a second p-electrode side pad overlapping the first p-electrode side pad; the first n-electrode side pad and the second n-electrode side pad are electrically connected, and the first p-electrode side pad and the second p-electrode side pad are electrically connected; The display device according to claim 1 .

4. the pixel includes a plurality of regions in which the first LED chip, the first mounting pad, the insulating layer, and the second mounting pad overlap in a plan view, At least one of the plurality of regions has a repair area on the second mounting pad from which the first LED chip, the first mounting pad, and the insulating layer have been removed; In the repair region, a second LED chip is electrically connected to the second mounting pad in place of the first LED chip. The display device according to claim 1 .

5. irradiating a first laser beam onto a first LED chip disposed in a pixel and determined to be defective, thereby removing the first LED chip; irradiating a first mounting pad disposed in the pixel and connected to the first LED chip with a second laser beam to remove the first mounting pad; irradiating an insulating layer overlapping the first mounting pad with a third laser beam to remove the insulating layer and expose a second mounting pad overlapping the first mounting pad in a plan view; Mounting a second LED chip on the second mounting pad; A method for repairing a display device.

6. the first laser beam, the second laser beam, and the third laser beam have different wavelengths; The method for repairing a display device according to claim 5 .

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