Display device and repair method

Abstract

The present invention addresses the problem of providing a display device in which a defective LED can be easily repaired. A display device (10) according to the present invention is configured to include 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) comprises a transparent driving substrate (100) and a plurality of micro LEDs (110) mounted on the transparent driving substrate (100). The micro LED unit (U2) includes a transparent repair substrate (200) and a repair LED (210R) mounted on the transparent repair substrate (200). The repair LED (210R) is disposed at a position corresponding to the defective LED (110D) on the transparent drive substrate (100).

Description

Technical Field

[0001] The present invention relates to a display device having a plurality of light-emitting elements formed on a substrate, and more particularly to repairing a micro LED (light-emitting diode) when a defect occurs. Background Art

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

[0003] For example, Patent Document 1 discloses a passively driven LED stack for a display, in which a first red (R) LED stack, a second green (G) LED stack, and a third blue (B) LED stack are stacked in a vertical direction, and the anodes of the light-emitting diodes of the first LED stack to the third LED stack are commonly connected to the data wiring, and the cathodes are respectively connected to the scanning wirings 1, 2, and 3, so that the R, G, and B light-emitting diodes in the same pixel are driven independently.

[0004] Patent document 2 discloses an actively driven 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 in a manner covering the TFT, a first electrode connected to the source electrode via a conductive 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 thereon.

[0005] In a display using micro-LEDs, if a micro-LED fails or is poorly installed, it needs to be repaired. For example, Patent Document 3 discloses a repair method, which heats a defective LED chip with a laser and transfers it to an adhesive film to remove it from a substrate on which a plurality of LED chips are mounted. Patent Document 4 discloses a chip repair method, which prepares a transfer carrier holding a supplementary chip, aligns and faces a repair target portion of a repair target substrate with a supplementary chip held by the transfer carrier, and transfers the supplementary chip to the repair target substrate.

[0006] Prior art literature:

[0007] Patent Literature:

[0008] Patent Document 1: Japanese Patent Application Publication No. 2021-504752

[0009] Patent Document 2: U.S. Patent No. 11,171,270

[0010] Patent Document 3: Japanese Patent Application Publication No. 2022-140934

[0011] Patent Document 4: Japanese Patent Application Publication No. 2023-3062 Summary of the invention

[0012] Problems to be solved by the invention:

[0013] The conventional method of repairing micro-LEDs requires the following steps: (1) detecting the abnormal position of the defective micro-LED on the substrate by inspection, (2) removing the defective micro-LED from the substrate, and (3) reinstalling the repaired micro-LED on the substrate. However, when removing the micro-LED, it is necessary to heat it with a laser without damaging the wiring pattern, which requires delicate operations and a lot of man-hours, and there is a problem of increasing the impact of costs.

[0014] An object of the present invention is to solve such conventional problems and to provide a display device and a repair method capable of repairing a defective LED easily and at a reduced cost.

[0015] Means used to solve the problem:

[0016] The display device involved in the present invention includes a first substrate on which a plurality of light-emitting elements are arranged in a two-dimensional shape, and a second substrate stacked on the first substrate, at least the second substrate is transparent, and on the second substrate, light-emitting elements for repair are arranged at positions corresponding to defective light-emitting elements on the first substrate.

[0017] In one embodiment, the first substrate and the second substrate are common. In one embodiment, the first wiring formed on the surface of the first substrate and the second wiring formed on the surface of the second substrate have the same structure. In one embodiment, the display device also includes a driving circuit connected to the first wiring and the second wiring, and the driving circuit drives the light-emitting elements on the first substrate and the light-emitting elements on the second substrate at the same time. In one embodiment, on the second substrate, a plurality of light-emitting elements are formed at positions that do not overlap with the plurality of light-emitting elements on the first substrate. In one embodiment, the first wiring and the second wiring each include 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 light-emitting element for repair at the intersection of a selected data line and a selected scan line. In one embodiment, the light-emitting element is a micro-LED.

[0018] The repair method involved in the present invention is a method for repairing a defective LED in a transparent display installed with multiple micro LEDs, wherein a second transparent substrate is stacked on a first transparent substrate including the defective LED, and a repair LED is installed at a position on the second transparent substrate corresponding to the defective LED.

[0019] Effect of the invention:

[0020] According to the present invention, a light emitting element for repair is arranged on the second substrate stacked on the first substrate, so there is no need to remove the defective light emitting element from the first substrate, thereby simplifying and improving the efficiency of the repair operation and suppressing the increase in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a block diagram showing a schematic configuration of a display device according to an embodiment of the present invention.

[0022] Figure 2 It is a schematic cross-sectional view of a transparent display according to an embodiment of the present invention.

[0023] Figure 3 It is a schematic cross-sectional view of a transparent display of a display device according to a first embodiment of the present invention.

[0024] Figure 4 (A) is a schematic plan view of the transparent drive substrate involved in the first embodiment, Figure 4 (B) is a schematic plan view of the transparent repair substrate involved in the first embodiment.

[0025] Figure 5 It is a schematic cross-sectional view of a transparent display according to a second embodiment of the present invention.

[0026] Figure 6 It is a schematic cross-sectional view of a transparent display according to a third embodiment of the present invention.

[0027] Description of reference numerals:

[0028] 10: Display device 20: Driving circuit

[0029] 30: Transparent display 100: Transparent drive substrate

[0030] 110: Micro LED 110D: Defective LED

[0031] 120: Transparent protective agent 130: Substrate wiring

[0032] 200: Transparent repair substrate 210R: Repair LED

[0033] 220: Substrate wiring 230: Transparent protective agent

[0034] 300: Transparent drive lower substrate 400: Transparent drive upper substrate

[0035] U1, U2: Micro LED units DETAILED DESCRIPTION

[0036] The present invention relates to a display device including a substrate on which a plurality of light-emitting elements are formed, and more particularly to a display device in which a light-emitting element for repairing a defective light-emitting element is arranged on a laminated substrate when a defect of the light-emitting element is detected. The light-emitting element is not particularly limited, and may be, for example, a micro LED. It should be noted that the drawings referred to in the following description include exaggerated displays for the purpose of making the invention easier to understand, and do not represent the shape or proportion of an actual product as it is.

[0037] Figure 1 1 is a block diagram showing the structure of a display device according to an embodiment of the present invention. As shown in the figure, the display device 10 is configured to include 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 independently driven by the driving circuit 20.

[0038] Figure 2 : is a schematic cross-sectional view of the transparent display 30. The micro LED unit U1 on the lower side 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 in a manner to cover the surface of the transparent driving substrate 100 including the plurality of micro LEDs 110. The micro LED unit U2 on the upper side 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 in a manner 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 in a manner that the back surface thereof is in contact with the transparent protective agent 120.

[0039] When a defective LED 110D is detected from among the plurality of micro LEDs 110 mounted on the transparent drive substrate 100, a repair LED 210 is mounted at a position corresponding to the defective LED 110D of the transparent repair substrate 200, that is, at a position directly above the defective LED 110D. When the transparent display 30 displays an image, the transparent drive substrate 100 and the transparent repair substrate 200 are driven simultaneously, and the user E sees a composite image generated by the transparent drive substrate 100 and an image generated by the transparent repair substrate 200.

[0040] In this way, by compensating the defective LED 110D of the transparent driving substrate 100 with the LED 210 of the laminated transparent repair substrate 200, it is possible to eliminate the conventional operation of removing the defective LED 110D from the transparent driving substrate 100. In addition, although the upper micro LED unit U2 needs to be composed of a transparent substrate, the lower micro LED unit U1 does not necessarily need to be a transparent substrate.

[0041] Transparent displays using micro-LEDs are equipped with LED chips of tens of um. In a full HD (High Definition) display, the number of pixels is 1920×1080, and the number of LED chips installed is 1920×1080×3 (RGB), which means that approximately 6.22 million LED chips are installed. Therefore, LED defects are frequent and repair operations are required. In previous repair operations, the removal or transfer of defective LEDs required a lot of man-hours. These processes required delicate operations to avoid damaging the wiring pattern on the substrate, resulting in increased costs. In contrast, as in the present embodiment, by stacking a transparent repair substrate and installing a repair LED thereon, the process can be simplified and is also cost-effective.

[0042] [Example]

[0043] Next, a first embodiment of the present invention will be described. Figure 3 is a schematic cross-sectional view of a transparent display of a display device according to a first embodiment of the present invention, Figure 2 The same reference numerals are attached to the same structures.

[0044] The lower micro LED unit U1 includes a rectangular transparent drive substrate 100. The transparent drive substrate 100 is formed by using a light-transmitting substrate such as glass, plastic, or acrylic, or a transparent film.

[0045] A substrate wiring 130 is formed on the surface of the transparent driving substrate 100. The material of the substrate wiring 130 is not particularly limited, and may be, for example, a conductive material such as Cu, or a light-transmitting conductive material such as ITO, and a wiring pattern (such as a data electrode wiring or a scanning electrode wiring, etc.) is formed on the transparent driving substrate 100 by these conductive materials.

[0046] A plurality of micro LEDs 110 are mounted on the surface of the transparent drive substrate 100 in a matrix or arbitrary pattern (e.g., 8-segment display) in a manner electrically connected to the substrate wiring 130. For example, at each intersection of the data electrode wiring and the scanning electrode wiring, one electrode of the micro LED is connected to the data electrode wiring, and the other electrode is connected to the scanning electrode wiring.

[0047] A transparent protective agent 120 is formed on the transparent driving substrate 100 so as to cover the plurality of micro LEDs 110. The transparent protective agent 120 is not particularly limited and is made of a material such as PET (polyethylene terephthalate), PP (polypropylene), or PVC (polyvinyl chloride).

[0048] The upper micro LED unit U2 includes a transparent repair substrate 200, on the surface of which a substrate wiring 230 is formed. In a certain embodiment, the transparent repair substrate 200 has the same material, the same size, and the same substrate wiring as the transparent drive substrate 100, so the transparent drive substrate 100 and the transparent repair substrate 200 are common. In other embodiments, the transparent repair substrate 200 can also be composed of a different material, a different size, and a different substrate wiring than the transparent drive substrate 200. However, the former embodiment is cost-effective because the transparent substrate is made common.

[0049] On the transparent repair substrate 200, a repair LED 210 is mounted at a position corresponding to the defective LED on the transparent drive substrate 100. The repair LED 210 is mounted on the transparent repair substrate 200 by, for example, thermally pressing a material containing conductive particles on 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.

[0050] Figure 4 (A) is a schematic plan view of a transparent driving substrate, Figure 4 (B) is a schematic plan view of a transparent repair substrate. Figure 4 As shown in (A), on the transparent driving substrate 100, as substrate wiring 130, a plurality of scanning 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, and micro LEDs 110 are connected at each intersection of the plurality of scanning electrode wirings and the plurality of data electrode wirings. Here, for convenience, 6 passively driven scanning electrode wirings and data electrode wirings are illustrated, but in fact, scanning electrode wirings and data electrode wirings corresponding to the number of pixels (Pixel number) are formed. In addition, a switching element can also be configured at the intersection of the scanning electrode wiring and the data electrode wiring to set it as active drive.

[0051] The scanning electrode wiring and the data electrode wiring are illustrated as straight lines, but the shape or pattern of the wiring is appropriately determined according to the position of the anode / cathode of the micro LED. At the intersection of the scanning electrode wiring and the data electrode wiring, for example, the cathode electrode of the micro LED is electrically connected to the scanning electrode wiring, and the anode electrode of the micro LED is electrically connected to the data electrode wiring.

[0052] In addition, Figure 4In (A), one pixel 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 composition of the R, G, and B sub-pixels is not particularly limited. For example, they can be composed of a diode that emits red light, a diode that emits green light, and a diode that emits blue light, or they can be formed by using a fluorescent filter that generates red and green from a diode that emits blue light to form R and G light-emitting elements. In the case of sub-pixels including R, G, and B, each of the R, G, and B sub-pixels is connected to the scanning electrode wiring and the data electrode wiring, respectively. In addition, the micro-LED can also be, for example, a white diode that generates white light or an infrared diode that generates infrared light.

[0053] exist Figure 4 In (A), two defective LEDs 110D are illustrated at the intersection of the scanning electrode wiring S5 and the data electrode wiring D6 and the intersection of the scanning electrode wiring S6 and the data electrode wiring D4. In the case where the micro-LED includes sub-pixels of R, G, and B, the defective LED 110D represents a defect in one of the sub-pixels of R, G, and B. The defect of the LED includes, for example, a poor connection between the anode / cathode electrodes of the micro-LED and the wiring, or a failure or defect of the LED itself.

[0054] In a certain mode, when detecting a defective LED, all micro LEDs 110 mounted on the transparent drive substrate 100 are fully lit, and the positions of the micro LEDs that are not lit at this time are identified. For example, a camera is used to capture images of the micro LEDs in the fully lit state of the transparent drive substrate 100, and the positions of the micro LEDs that are not lit are detected from the captured images, and are determined to be defective LEDs. 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.

[0055] Figure 4 The scanning electrode wiring and the data electrode wiring shown in (A) are wirings for passive driving. Figure 1 The driving circuit 20 shown in the figure drives the scanning electrode wiring in time division at a certain scanning frequency, and applies a data signal (driving current) corresponding to the image data to be displayed to the data electrode wiring D1, D2, ..., D5, D6 in synchronization with the scanning frequency of the scanning electrode wiring. As a result, the micro LED emits light at a brightness corresponding to the applied data signal.

[0056] For example, if the scanning electrode wiring S1 is driven, the data signals from the data electrode wirings D1, D2, ..., D5, and D6 are applied to each micro-LED at the intersection of the scanning electrode wiring S1 and the data electrode wirings D1, D2, ..., D5, and D6, and the micro-LEDs on the line light up. Next, if the scanning electrode wiring S2 is driven, the data signals from the data electrode wirings D1, D2, ..., D5, and D6 are applied to each micro-LED at the intersection of the scanning electrode wiring S2, and the micro-LEDs on the line light up. By driving the scanning electrode wirings sequentially from S1 to S6 in this way, one frame of display is performed. In the example, the defective LED 110D at the intersection of the scanning electrode wiring S5 and the data electrode wiring D6, and the defective LED 110D at the intersection of the scanning electrode wiring S6 and the data electrode wiring D4 are not lit.

[0057] The transparent repair substrate 200 is as follows Figure 4 As shown in (B), the transparent repair substrate 200 has the same substrate wiring as the transparent drive substrate 100, that is, the same scanning electrode wiring and data electrode wiring as the transparent drive substrate 100. However, only the repair LED 210 for compensating the defective LED 110D is mounted on the transparent repair substrate 200. For example, if the defective LED is the micro LED of R in the sub-pixel, the repair LED is the micro LED of R. When the transparent repair substrate 200 is aligned with the transparent drive substrate 100, the repair LED 210 is arranged at the position corresponding to the defective LED 110D.

[0058] The driving circuit 20 is connected to the micro LED units U1 and U2, respectively, and drives the micro LED units U1 and U2 independently and simultaneously. That is, the scanning electrode wiring and the data electrode wiring of each of the transparent driving electrode 100 and the transparent repair electrode 200 are driven simultaneously. For example, when the scanning electrode wiring S5 is scanned, although the defective LED 110D of the data electrode wiring D6 of the transparent driving substrate 100 is not lit, the repair LED 210R of the transparent repair substrate 200 is lit in accordance with the data signal applied from the data electrode wiring D6. Next, when the scanning electrode wiring S6 is scanned, although the defective LED 110D of the data electrode wiring D4 of the transparent driving substrate 100 is not lit, the repair LED 210R of the transparent repair substrate 200 is lit in accordance with the data signal applied from the data electrode wiring D4.

[0059] According to this embodiment, by making the transparent drive substrate and the transparent repair substrate common, repair can be performed using only the existing transparent drive substrate without developing a new transparent repair substrate, resulting in a reduction in the cost of the display device.

[0060] Next, a second embodiment of the present invention will be described. Figure 51 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 driving substrate 100 used in the first embodiment is coupled to the substrate wiring 230 of the transparent repair substrate 200 through the wiring 240, and the coupled wiring 240 is connected to the driving circuit 20. The driving circuit 20 drives the transparent driving substrate 100 and the transparent repair substrate 200 in common through the wiring 240. Thus, a dedicated driving circuit for the transparent repair substrate 200 is not required, and the cost can be reduced. In addition, since the transparent driving substrate 100 and the transparent repair substrate 200 are the same wiring substrate, when connecting the wiring, if a substrate-to-substrate connector is used, the two can be easily connected.

[0061] Next, a third embodiment of the present invention is described. In the third embodiment, in order to realize a high-resolution and high-definition transparent display, a method of stacking transparent drive substrates with micro LEDs mounted thereon is used, and a repair LED is mounted on the upper transparent drive substrate.

[0062] Figure 6 (A) is a schematic cross-sectional view of the transparent display 30A involved in the third embodiment. The transparent display 30A includes a stack of a micro LED unit U1 on the lower side and a micro LED unit U2 on the upper side. The micro LED unit U1 on the lower side includes a transparent driving lower substrate 300, a plurality of micro LEDs 310 mounted in a two-dimensional shape on the transparent driving lower substrate 300, and a transparent protective agent 320 covering the surface of the transparent driving lower substrate 300. The micro LED unit U2 on the upper side includes a transparent driving upper substrate 400, a plurality of micro LEDs 410 mounted in a two-dimensional shape on the transparent driving upper substrate 400, and a transparent protective agent 420 covering the surface of the transparent driving upper substrate 400.

[0063] The micro LEDs 320 mounted on the transparent driving lower substrate 300 are arranged at positions that do not overlap with the micro LEDs 420 mounted on the transparent driving upper substrate 400 , for example, arranged in a manner that the pitches in the row and column directions are offset by 1 / 2, that is, arranged in a staggered manner.

[0064] When the driving circuit 20 displays an image on the transparent display 30A, the micro LED unit U1 is time-division driven at a scanning frequency F1, and the micro LED unit 2 is time-division driven at a scanning frequency F2 (F2=F1). The light emitted from the micro LED 310 of the transparent driven lower substrate 300 is incident from the back of the transparent driven upper substrate 400, and is emitted from the surface of the transparent protective agent 420. On the other hand, the light emitted from the micro LED 410 of the transparent driven upper substrate 400 is also emitted from its surface via the transparent protective agent 420. Thus, a high-resolution, high-definition image that is synthesized by the frame image generated by the micro LED unit U1 and the frame image generated by the micro LED unit U2 can be displayed.

[0065] Here, if Figure 6 As shown in (B), when a defective LED 310D is detected in the transparent driving lower substrate 300 , a repair LED 410R is mounted at a position corresponding to the defective LED 310D on the transparent driving upper substrate 400 .

[0066] As described above, according to this embodiment, when a high-definition transparent display is formed by stacking transparent driving substrates, it is sufficient to configure a repair LED on the transparent driving upper substrate, without the need to newly add a repair substrate as in the first and second embodiments, thereby achieving a more cost-effective structure.

[0067] 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 can be made within the scope of the gist of the invention described in the claims.

Claims

1. A display device, wherein: include: A first substrate having a plurality of light emitting elements arranged in a two-dimensional shape; as well as The second substrate is stacked on the first substrate. At least the second substrate is transparent, and a repair light emitting element is arranged on the second substrate at a position corresponding to the defective light emitting element on the first substrate.

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

3. The display device according to claim 2, wherein: The first wiring formed on the surface of the first substrate and the second wiring formed on the surface of the second substrate have the same structure.

4. The display device according to claim 3, wherein: 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.

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

6. The display device according to claim 3, wherein: The first wiring and the second wiring each include a plurality of data lines and a plurality of scan lines. The first substrate includes a light emitting element at each intersection of a plurality of data lines and a plurality of scanning lines. The second substrate includes a light emitting element for repair at an intersection of a selected data line and a selected scanning line.

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

8. A repair method for a defective LED in a display having a plurality of micro-LEDs installed therein, wherein: stacking a second transparent substrate on the first substrate including the defective LED, A repair LED is mounted on the second transparent substrate at a position corresponding to the defective LED.

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