Display device and repair method

Abstract

To provide a display device capable of easily repairing a defective LED.SOLUTION: A display device 10 comprises: a drive circuit 20; and a transparent display 30 having micro LED units U1, U2 driven by the drive circuit 20. The micro LED unit U1 includes a transparent drive substrate 100 and a plurality of micro LEDs 110 mounted thereon. The micro LED unit U2 has a transparent repair substrate 200 and a repair LED 210R mounted thereon. The repair LED 210R is arranged in a position corresponding to a defective LED 110D on the transparent drive substrate 100.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a display device in which a plurality of light-emitting elements are formed on a substrate, and in particular to repair when a defect occurs in a micro LED (light-emitting diode). [Background technology]

[0002] In recent years, micro LEDs have been developed that can display images directly from light emitting diodes. Micro LEDs are arranged two-dimensionally to correspond to each pixel, and in color images, each pixel is composed of blue, green, and red sub-pixels.

[0003] For example, Patent Document 1 discloses a passive drive type LED stack for displays in which a first LED stack of red (R), a second LED stack of green (G), and a three LED stack of blue (B) are stacked vertically, the anodes of each light-emitting diode of the first LED stack to the third LED stack are commonly connected to a data wiring, and the cathodes are connected to scan wirings 1, 2, and 3, respectively, to independently drive the R, G, and B light-emitting diodes in the same pixel.

[0004] Patent Document 2 discloses an active-drive micro LED in which a thin film transistor (TFT) including a gate electrode, a drain electrode, and a source electrode is formed on a semiconductor layer, a planarization layer is formed to cover the TFT, a first electrode connected to the source electrode through a via hole in the planarization layer is formed on the planarization layer, and an LED is formed between the first electrode and a second electrode formed above the first electrode.

[0005] In a display using micro LEDs, when a micro LED breaks down or has a mounting defect, it is necessary to repair it. For example, Patent Document 3 discloses a repair method in which a defective LED chip is heated with a laser and transferred to an adhesive film from a substrate on which many LED chips are mounted, and then removed. Patent Document 4 discloses a chip repair method in which a transfer carrier holding a refill chip is prepared, a repair target portion of a substrate to be repaired and the refill chip held by the transfer carrier are aligned and opposed to each other, and the refill chip is transferred to the substrate to be repaired. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-504752 [Patent Document 2] U.S. Patent No. 11,171,270 [Patent Document 3] JP 2022-140934 A [Patent Document 4] JP 2023-3062 A Summary of the Invention [Problem to be solved by the invention]

[0007] Conventional methods for repairing micro LEDs require the steps of (1) detecting abnormal parts of defective micro LEDs on a substrate through inspection, (2) removing the defective micro LEDs from the substrate, and (3) remounting a repair micro LED on the substrate. However, when removing the micro LEDs, they must be heated with a laser to be removed, and the wiring pattern must not be damaged during the process, which requires delicate work and a large number of man-hours, resulting in a large cost impact.

[0008] An object of the present invention is to provide a display device and a repair method that can solve the above-mentioned problems and repair defective LEDs easily and at low cost. [Means for solving the problem]

[0009] The display device of the present invention includes a first substrate on which a plurality of light-emitting elements are arranged two-dimensionally, and a second substrate stacked on the first substrate, where at least the second substrate is transparent, and repair light-emitting elements are arranged on the second substrate at positions corresponding to defective light-emitting elements on the first substrate.

[0010] In one embodiment, the first substrate is common to the second substrate. In one embodiment, the first wiring formed on the surface of the first substrate has the same configuration as the second wiring formed on the surface of the second substrate. In one embodiment, the display device further includes a driving circuit connected to the first wiring and the second wiring, and the driving circuit drives the light-emitting element on the first substrate and the light-emitting element on the second substrate simultaneously. In one embodiment, a plurality of light-emitting elements are formed on the second substrate at positions that do not overlap with the plurality of light-emitting elements on the first substrate. In one embodiment, each of the first and second wirings includes a plurality of data lines and a plurality of scan lines, the first substrate includes a light-emitting element at each intersection of the plurality of data lines and the plurality of scan lines, and the second substrate includes a repair light-emitting element at an intersection of a selected data line and a selected scan line. In one embodiment, the light-emitting element is a micro LED.

[0011] The repair method of the present invention is a method for repairing a defective LED in a transparent display equipped with a plurality of micro LEDs, which comprises stacking a second transparent substrate on a first transparent substrate containing the defective LED, and attaching a repair LED to a position on the second transparent substrate corresponding to the defective LED. Effect of the Invention

[0012] According to the present invention, a repair light-emitting element is arranged on a second substrate stacked on a first substrate, eliminating the need for a process of removing the defective light-emitting element from the first substrate, thereby simplifying and streamlining the repair work and preventing cost increases. [Brief description of the drawings]

[0013] [Figure 1] 1 is a block diagram showing a schematic configuration of a display device according to an embodiment of the present invention. [Diagram 2] 1 is a schematic cross-sectional view of a transparent display according to an embodiment of the present invention. [Diagram 3] 1 is a schematic cross-sectional view of a transparent display of a display device according to a first embodiment of the present invention. [Figure 4] FIG. 4(A) is a schematic plan view of a transparent driving substrate according to the first embodiment, and FIG. 4(B) is a schematic plan view of a transparent repair substrate according to the first embodiment. [Diagram 5] FIG. 4 is a schematic cross-sectional view of a transparent display according to a second embodiment of the present invention. [Figure 6] FIG. 11 is a schematic cross-sectional view of a transparent display according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention relates to a display device including a substrate on which a plurality of light-emitting elements are formed, and in particular to a display device in which, when a defect in a light-emitting element is detected, a light-emitting element for repairing the defective light-emitting element is disposed on the substrate to be stacked. The light-emitting element is not particularly limited, but is, for example, a micro LED. It should be noted that the drawings referred to in the following description include exaggerated representations to facilitate understanding of the invention, and do not directly represent the shape and scale of the actual product.

[0015] 1 is a block diagram showing a configuration of a display device according to an embodiment of the present invention. As shown in the figure, the display device 10 includes a driving circuit 20 and a transparent display 30 driven by the driving circuit 20. The transparent display 30 includes a stack of two micro LED units U1 and U2, and the micro LED units U1 and U2 are each independently driven by the driving circuit 20.

[0016] 2 is a schematic cross-sectional view of a transparent display 30. The lower micro LED unit U1 includes a transparent driving substrate 100, a plurality of micro LEDs 110 arranged in a matrix on the transparent driving substrate 100, and a transparent protective agent 120 formed to cover the surface of the transparent driving substrate 100 including the plurality of micro LEDs 110. The upper micro LED unit U2 includes a transparent repair substrate 200, one or more repair LEDs 210 arranged on the transparent repair substrate 200, and a transparent protective agent 220 formed to cover the surface of the transparent repair substrate 200 including the repair LEDs 210. The transparent repair substrate 200 is laminated on the transparent driving substrate 110 so that its back surface is in contact with the transparent protective agent 120.

[0017] When a defective LED 110D is detected from among the multiple micro LEDs 110 mounted on the transparent drive substrate 100, a repair LED 210 is attached to the transparent repair substrate 200 at a position corresponding to the defective LED 110D, i.e., directly above the defective LED 110D. When an image is displayed on the transparent display 30, the transparent drive substrate 100 and the transparent repair substrate 200 are driven simultaneously, and a user E sees a composite image generated by the transparent drive substrate 100 and the transparent repair substrate 200.

[0018] In this way, by compensating for the defective LED 110D of the transparent drive substrate 100 with the LED 210 of the laminated transparent repair substrate 200, it is possible to eliminate the need to remove the defective LED 110D from the transparent drive substrate 100 as in the conventional method. Note that the upper micro LED unit U2 needs to be made of a transparent substrate, but the lower micro LED unit U1 does not necessarily need to be made of a transparent substrate.

[0019] Transparent displays using micro LEDs are equipped with LED chips of several tens of microns. In a full HD (High Definition) display, the number of pixels is 1920 x 1080, and the number of LED chips to be mounted is 1920 x 1080 x 3 (RGB), that is, about 6.22 million chips are mounted. Therefore, LED defects occur frequently, and repair work is essential. Conventional repair work requires many steps to remove and transfer defective LEDs, and these steps require delicacy so as not to damage the wiring pattern on the substrate, which leads to increased costs. In contrast, stacking a transparent repair substrate and mounting repair LEDs on it, as in this embodiment, can simplify the process and is also advantageous in terms of cost. EXAMPLES

[0020] Next, a first embodiment of the present invention will be described. Fig. 3 is a schematic cross-sectional view of a transparent display of a display device according to a first embodiment of the present invention, and the same components as those in Fig. 2 are given the same reference numerals.

[0021] The lower micro LED unit U1 includes a rectangular transparent drive substrate 100. The transparent drive substrate 100 is configured using, for example, a light-transmitting substrate such as glass, plastic, or acrylic, or a transparent film.

[0022] The substrate wiring 130 is formed on the surface of the transparent drive substrate 100. The material of the substrate wiring 130 is not particularly limited, but may be, for example, a conductive material such as Cu or a light-transmitting conductive material such as ITO, and a wiring pattern (for example, data electrode wiring, scan electrode wiring, etc.) is formed on the transparent drive substrate 100 by these conductive materials.

[0023] A plurality of micro LEDs 110 are mounted in a matrix or in any pattern (e.g., an 8-segment display) on the surface of the transparent driving substrate 100 so as to be electrically connected to the substrate wiring 130. For example, at each intersection of the data electrode wiring and the scan electrode wiring, one electrode of the micro LED is connected to the data electrode wiring, and the other electrode is connected to the scan electrode wiring.

[0024] A transparent protective agent 120 is formed on the transparent driving substrate 100 so as to cover the multiple micro LEDs 110. The transparent protective agent 120 is made of a material such as, but not limited to, PET (polyethylene terephthalate), PP (polypropylene), or PVC (polyvinyl chloride).

[0025] The upper micro LED unit U2 includes a transparent repair substrate 200, and a substrate wiring 230 is formed on the surface thereof. In one embodiment, the transparent repair substrate 200 has the same material, size, and substrate wiring as the transparent drive substrate 100, and therefore the transparent drive substrate 100 and the transparent repair substrate 200 are common. In another embodiment, the transparent repair substrate 200 may be made of a different material, size, and substrate wiring from the transparent drive substrate 200. However, the former embodiment is more cost-effective because the transparent substrate is common.

[0026] A repair LED 210 is mounted on the transparent repair substrate 200 at a position corresponding to a defective LED on the transparent drive substrate 100. The repair LED 210 is mounted on the transparent repair substrate 200 by, for example, thermocompression bonding a material containing conductive particles onto the substrate wiring 230. In addition, a transparent protective agent 220 is formed on the transparent repair substrate 200 so as to cover one or more repair LEDs 210.

[0027] FIG. 4(A) is a schematic plan view of a transparent driving substrate, and FIG. 4(B) is a schematic plan view of a transparent repair substrate. As shown in FIG. 4(A), on the transparent driving substrate 100, a plurality of scan electrode wirings S1, S2, . . . , S5, S6 extending in the row direction (X direction) and a plurality of data electrode wirings D1, D2, . . . , D5, D6 extending in the column direction (Y direction) are formed as substrate wirings 130, and micro LEDs 110 are connected to each intersection of the plurality of scan electrode wirings and the plurality of data electrode wirings. Here, for convenience, six passively driven scan electrode wirings and data electrode wirings are illustrated, but in reality, the number of scan electrode wirings and data electrode wirings corresponding to the number of pixels (pixel number) are formed. Note that switching elements may be disposed at the intersections of the scan electrode wirings and data electrode wirings to perform active driving.

[0028] Although the scan electrode wiring and the data electrode wiring are illustrated as straight lines, the shape and pattern of the wiring are appropriately determined according to the positions of the anode / cathode of the micro LED. At the intersection of the scan electrode wiring and the data electrode wiring, for example, the cathode electrode of the micro LED is electrically connected to the scan electrode wiring, and the anode electrode of the micro LED is electrically connected to the data electrode wiring.

[0029] In addition, in FIG. 4(A), one pixel (picture element) is illustrated as one micro LED, but when the transparent display 30 displays a color image, one pixel is composed of three sub-pixels that generate R (red), G (green), and B (blue). The configuration of the R, G, and B sub-pixels is not particularly limited, but may be composed of, for example, a diode that emits red light, a diode that emits green light, and a diode that emits blue light, or may be formed as R and G light-emitting elements using a fluorescent filter that generates red and green light from a diode that emits blue light. When the R, G, and B sub-pixels are included, each of the R, G, and B sub-pixels is connected to a scan electrode wiring and a data electrode wiring, respectively. The micro LED may be, for example, a white diode that generates white light, or an infrared diode that generates infrared light.

[0030] 4A illustrates two defective LEDs 110D at an intersection of the scan electrode wiring S5 and the data electrode wiring D6 and at an intersection of the scan electrode wiring S6 and the data electrode wiring D4. When the micro LED includes R, G, and B subpixels, the defective LED 110D represents a defect in one of the R, G, and B subpixels. The defect in the LED includes, for example, a connection failure between the anode / cathode electrodes of the micro LED and the wiring, or a failure or defect in the LED itself.

[0031] In one embodiment, the defective LED is detected by fully lighting all the micro LEDs 110 mounted on the transparent drive substrate 100, and identifying the position of the micro LED that is not lit at this time. For example, an imaging camera is used to capture the micro LEDs in the fully lit state of the transparent drive substrate 100, and the position of the micro LED that is not lit is detected from the captured image, and this is determined to be a defective LED. The detection process of the defective LED is performed, for example, using a computer device, and the position information of the defective LED is used when mounting the repair LED 210 on the transparent repair substrate 200.

[0032] The scan electrode wiring and data electrode wiring shown in Fig. 4(A) are wiring for passive driving. The driving circuit 20 shown in Fig. 1 drives the scan electrode wiring in a time-division manner at a constant scan frequency, and applies data signals (driving currents) corresponding to image data to be displayed to the data electrode wirings D1, D2, ..., D5, and D6 in synchronization with the scan frequency of the scan electrode wiring. This causes the micro LED to emit light with a brightness corresponding to the applied data signal.

[0033] For example, when the scan electrode wiring S1 is driven, data signals from the data electrode wirings D1, D2, ..., D5, D6 are applied to each micro LED at the intersection of the scan electrode wiring S1 and the data electrode wirings D1, D2, ..., D5, D6, and the micro LEDs of this line are turned on, and then when the scan electrode wiring S2 is driven, data signals from the data electrode wirings D1, D2, ..., D5, D6 are applied to each micro LED at the intersection of the scan electrode wiring S2, and the micro LEDs of this line are turned on. In this way, one frame is displayed by sequentially driving the scan electrode wirings from S1 to S6. In the example shown in the figure, the defective LED 110D at the intersection of the scan electrode wiring S5 and the data electrode wiring D6 and the defective LED 110D at the intersection of the scan electrode wiring S6 and the data electrode wiring D4 are not turned on.

[0034] 4(B), the transparent repair substrate 200 has the same substrate wiring as the transparent drive substrate 100, that is, the same scan electrode wiring and data electrode wiring. However, only the repair LED 210 for compensating for the defective LED 110D is mounted on the transparent repair substrate 200. For example, if the defective LED is an R micro LED of a subpixel, the repair LED is an R micro LED. When the transparent repair substrate 200 is aligned with the transparent drive substrate 100, the repair LED 210 is disposed at a position corresponding to the defective LED 110D.

[0035] The driving circuit 20 is connected to the micro LED units U1 and U2, respectively, and drives the micro LED units U1 and U2 simultaneously and independently. That is, it drives the scan electrode wiring and the data electrode wiring of the transparent driving electrode 100 and the transparent repair electrode 200 simultaneously. For example, when the scan electrode wiring S5 is scanned, the defective LED 110D of the data electrode wiring D6 of the transparent driving substrate 100 is not turned on, but the repair LED 210R of the transparent repair substrate 200 is turned on according to the data signal applied from the data electrode wiring D6, and then, when the scan electrode wiring S6 is scanned, the defective LED 110D of the data electrode wiring D4 of the transparent driving substrate 100 is not turned on, but the repair LED 210R of the transparent repair substrate 200 is turned on according to the data signal applied from the data electrode wiring D4.

[0036] According to this embodiment, by making the transparent drive substrate and the transparent repair substrate common to each other, repairs can be made using only the existing transparent drive substrate without starting a new transparent repair substrate, thereby enabling the cost of the display device to be reduced.

[0037] Next, a second embodiment of the present invention will be described. FIG. 5 is a schematic cross-sectional view of a transparent display according to the second embodiment. In the second embodiment, the substrate wiring 130 of the transparent drive substrate 100 used in the first embodiment and the substrate wiring 230 of the transparent repair substrate 200 are connected by wiring 240, and the connected wiring 240 is connected to the drive circuit 20. The drive circuit 20 drives the transparent drive substrate 100 and the transparent repair substrate 200 in common through the wiring 240. This makes it possible to eliminate the need for a dedicated drive circuit for the transparent repair substrate 200, thereby reducing costs. Note that since the transparent drive substrate 100 and the transparent repair substrate 200 are the same wiring substrate, the two can be easily connected by using an inter-substrate connector for wiring connection.

[0038] Next, a third embodiment of the present invention will be described. In the third embodiment, in order to realize a high-resolution and high-definition transparent display, a method of stacking transparent drive substrates on which micro LEDs are mounted is used, and a repair LED is mounted on the upper transparent drive substrate.

[0039] 6(A) is a schematic cross-sectional view of a transparent display 30A according to a third embodiment. The transparent display 30A includes a lower micro LED unit U1 and an upper micro LED unit U2 stacked together. The lower micro LED unit U1 includes a transparent driving lower substrate 300, a plurality of micro LEDs 310 mounted two-dimensionally on the transparent driving lower substrate 300, and a transparent protective agent 320 covering the surface of the transparent driving lower substrate 300. The upper micro LED unit U2 includes a transparent driving upper substrate 400, a plurality of micro LEDs 410 mounted two-dimensionally on the transparent driving upper substrate 400, and a transparent protective agent 420 covering the surface of the transparent driving upper substrate 400.

[0040] The micro LEDs 320 mounted on the transparent driving lower substrate 300 are arranged in positions that do not overlap with the micro LEDs 420 mounted on the transparent driving upper substrate 400, for example, so that the pitch in the row and column directions is shifted by 1 / 2, i.e., so that they are staggered.

[0041] When displaying an image on the transparent display 30A, the driving circuit 20 drives the micro LED unit U1 at a scanning frequency F1 in a time-division manner, and drives the micro LED unit 2 at a scanning frequency F2 (F2=F1) in a time-division manner. The light emitted from the micro LED 310 of the transparent driving lower substrate 300 enters the back surface of the transparent driving upper substrate 400 and is emitted from the front surface of the transparent protective agent 420. On the other hand, the light emitted from the micro LED 410 of the transparent driving upper substrate 400 is also emitted from the front surface through the transparent protective agent 420. This makes it possible to display a high-resolution, high-definition image in which the frame image generated by the micro LED unit U1 and the frame image generated by the micro LED unit U2 are synthesized.

[0042] Here, as shown in FIG. 6(B), when a defective LED 310D is detected on the transparent driving lower substrate 300, a repair LED 410R is attached to the transparent driving upper substrate 400 at a position corresponding to the defective LED 310D.

[0043] Thus, according to this embodiment, when a high-definition transparent display is constructed using a method in which transparent drive substrates are stacked, it is sufficient to place a repair LED on the upper transparent drive substrate, and a more cost-effective configuration can be realized without having to add a separate repair substrate, as in the first and second embodiments.

[0044] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes are possible within the scope of the gist of the invention described in the claims. [Explanation of symbols]

[0045] 10: Display device 10: Drive circuit 30: Transparent display 100: Transparent drive substrate 110: Micro LED 110D: Defective LED 120: Transparent protective agent 130: Board wiring 200: Transparent repair board 210R: Repair LED 220: Board wiring 230: Transparent protective agent 300: transparent drive lower substrate 400: transparent drive upper substrate U1, U2: Micro LED unit

Claims

1. a first substrate on which a plurality of light-emitting elements are arranged two-dimensionally; a second substrate laminated on the first substrate; A display device, wherein at least the second substrate is transparent, and repair light-emitting elements are disposed on the second substrate at positions corresponding to the defective light-emitting elements on the first substrate.

2. The display device according to claim 1 , wherein the first substrate is common to the second substrate.

3. 3. The display device according to claim 2, wherein the first wiring formed on the surface of the first substrate has the same configuration as the second wiring formed on the surface of the second substrate.

4. The display device according to claim 3 , further comprising a drive circuit connected to the first wiring and the second wiring, the drive circuit simultaneously driving the light-emitting element on the first substrate and the light-emitting element on the second substrate.

5. The display device according to claim 1 , wherein a plurality of light-emitting elements are formed on the second substrate at positions that do not overlap with the plurality of light-emitting elements on the first substrate.

6. each of the first and second wirings includes a plurality of data lines and a plurality of scan lines; the first substrate includes a light emitting element at each intersection of the plurality of data lines and the plurality of scan lines; 4. The display device of claim 3, wherein the second substrate includes repair light emitting elements at intersections of selected data lines and selected scan lines.

7. The display device according to claim 1 , wherein the light-emitting element is a micro LED.

8. 1. A method for repairing a defective LED in a display incorporating a plurality of micro LEDs, comprising: laminating a second transparent substrate on the first substrate including the defective LED; A repair method includes attaching a repair LED to a second transparent substrate at a position corresponding to the defective LED.

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