Matrix LED display

Abstract

To provide a matrix LED display which can be constituted of a one layer wiring board.SOLUTION: In the matrix LED display, a plurality of LED chips 20 are arranged in a matrix on a wiring board 10 provided with common wiring 11 extending in a first direction and segment wiring 12 extending in a second direction. A common wiring 11 arranged at a position where a plurality of LED chips 20 arrayed in a first direction are cut off is connected to an n-type electrode 24, and a segment wiring 12 arranged at a position where a plurality of LED chips 20 arrayed in a second direction are cut off is connected to a p-type electrode 25, so that a conductive path in the first direction and a conductive path in the second direction are three-dimensionally crossed in the LED chips 20, and the common wiring 11 and the segment wiring 12 are prevented from crossing each other on a wiring board 10, thereby constituting a matrix LED display with a single-layer wiring board 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a matrix LED display in which minute LEDs are arranged in a matrix at individual pixel positions. [Background technology]

[0002] A matrix LED display is a flat panel display that consists of tiny LEDs arranged in a matrix at each pixel position, and is superior in contrast, response speed, and energy efficiency compared to existing backlit LCD displays. The multiple LEDs arranged in a matrix are connected to a drive circuit, etc. by wiring on the board on which the LEDs are mounted.

[0003] As shown in Fig. 6, the wiring on the substrate 100 includes common wiring 101 and segment wiring 102 arranged in mutually orthogonal directions. The common wiring 101 is a wiring common to the multiple LED chips 200 arranged in the same row, and is connected to, for example, the n-type electrodes (cathode electrodes) of the LED chips 200. The segment wiring 102 is a wiring for each segment of the multiple LED chips 200 arranged in the same column, and is connected to, for example, the p-type electrodes (anode electrodes) of the LED chips 200. Note that Fig. 6 schematically shows the wiring structure on the wiring substrate 100 as seen from above the wiring substrate 100 through the LED chips 200 to the electrodes.

[0004] As shown by the dotted circle in Figure 6, the common wiring 101 and the segment wiring 102 intersect on the substrate 100, which requires two conductive layers on the substrate 100, and requires through-holes to connect the wiring between the two layers via via conductors. For example, Patent Documents 1 and 2 disclose such two-layer wiring. However, the need for two conductive layers and through-holes makes it difficult to implement certain types of displays using microLED technology. For example, transmissive displays that allow the user to see through the display and flexible displays require the use of transparent substrates, film substrates, or stretchable substrates, but it is difficult to realize substrates with high transmittance or flexibility using a two-layer structure.

[0005] In addition, a micro LED display is known in which, in a sub-pixel having an X-direction terminal connected to a wiring extending in the X direction and a Y-direction terminal connected to a wiring extending in the Y direction, the Y-direction terminal is formed by a first region and a second region spaced apart from the first region (the Y-direction terminal is divided in a direction intersecting the Y direction), the wiring extending in the X direction is passed between the first region and the second region in the Y-direction terminal to be continuously provided in the X direction, and the first region and the second region are bridge-connected by an LED electrode (see, for example, Patent Document 3). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-182613 [Patent Document 2] Patent Publication No. 2021-504752 [Patent Document 3] Japanese Patent Publication No. 2022-61868 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made to solve the problems described above, and aims to make it possible to construct a matrix LED display using a single layer wiring board, without relying on a configuration in which separated Y-direction terminals are bridge-connected using LED electrodes. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the present invention provides a matrix LED display in which a plurality of LED chips are arranged in a matrix on a wiring substrate provided with a plurality of common wirings extending in a first direction and a plurality of segment wirings extending in a second direction perpendicular to the first direction, wherein each LED chip is formed as a pn junction in which a p-type semiconductor layer and an n-type semiconductor layer are joined in a vertical structure, the n-type electrode and the p-type electrode of the LED chip are arranged in an insulated state, a common wiring is arranged at a position cutting through the plurality of LED chips arranged in an array in the first direction and the common wiring is connected to one of the p-type electrode and the n-type electrode of the plurality of LED chips, and a segment wiring is arranged at a position cutting through the plurality of LED chips arranged in an array in the second direction and the segment wiring is connected to the other electrode of the plurality of LED chips. [Effects of the Invention]

[0009] According to the present invention configured as described above, the vertical structure of the pn junction of the LED chip is utilized to create a three-dimensional intersection within the LED chip between a first-direction conduction path formed by connecting one of the p-type and n-type electrodes to the common wiring and a second-direction conduction path formed by connecting the other electrode to the segment wiring, thereby eliminating the need for the common wiring and segment wiring to cross on the wiring substrate. This makes it possible to configure a matrix LED display using a single-layer wiring substrate, without relying on a configuration in which LED electrodes bridge separate Y-direction terminals as in Patent Document 3. [Brief explanation of the drawings]

[0010] [Figure 1]FIG. 2 is a diagram showing an example of wiring in a matrix LED display according to the present embodiment. [Figure 2] FIG. 2 is a diagram schematically illustrating an example of a cross-sectional side structure of an LED chip. [Figure 3] FIG. 10 is a diagram showing another wiring example of the matrix LED display according to the present embodiment. [Figure 4] FIG. 10 is a diagram schematically showing another example of the side cross-sectional structure of the LED chip. [Figure 5] FIG. 10 is a diagram schematically showing another example of the side cross-sectional structure of the LED chip. [Figure 6] FIG. 1 is a diagram showing an example of wiring in a conventional matrix LED display. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a diagram showing an example of wiring in a matrix LED display according to this embodiment. Fig. 1 schematically shows the wiring structure on a wiring substrate 10 of the matrix LED display, seen from above the wiring substrate 10, with the LED chip 20 seen through to the electrodes 24 and 25.

[0012] As shown in FIG. 1, the matrix LED display of this embodiment is configured by arranging a plurality of LED chips 20 in a matrix on a wiring substrate 10 provided with a plurality of common wirings 11 extending in a first direction (row direction) and a plurality of segment wirings 12 extending in a second direction (column direction) perpendicular to the first direction.

[0013] In this embodiment, a common wiring 11 is arranged at a position cutting through the plurality of LED chips 20 arranged in an array in the first direction, and a segment wiring 12 is arranged at a position cutting through the plurality of LED chips 20 arranged in an array in the second direction. Here, the common wiring 11 is connected to the n-type electrode 24 (cathode electrode) of the LED chip 20, and the segment wiring 12 is connected to the p-type electrode 25 (anode electrode) of the LED chip 20.

[0014] Fig. 2 is a diagram schematically illustrating an example of a side cross-sectional structure of each LED chip 20. As shown in Fig. 2, the LED chip 20 is configured as a pn junction in which an n-type semiconductor layer 22 and a p-type semiconductor layer 23 are vertically bonded on a substrate 21. The n-type semiconductor layer 22 has a substantially U-shaped cross section, and is configured so that an end face of the n-type semiconductor layer 22 is aligned with an end face of the p-type semiconductor layer 23.

[0015] The LED chip 20 has an n-type electrode 24 to which the common wiring 11 is connected and a p-type electrode 25 to which the segment wiring 12 is connected, and the n-type electrode 24 and the p-type electrode 25 are provided in an insulated state. In this embodiment, the LED chip 20 has two n-type electrodes 24 and one p-type electrode 25. As shown in FIG. 1 , the two n-type electrodes 24 are arranged on both sides of the p-type electrode 25 along the first direction in which the common wiring 11 is arranged.

[0016] Two n-type electrodes 24 are connected to n-type semiconductor layer 22, and one p-type electrode 25 is connected to p-type semiconductor layer 23. As described above, the end face of n-type semiconductor layer 22 and the end face of p-type semiconductor layer 23 are configured to be flush with each other and have the same height, so the two n-type electrodes 24 and p-type electrode 25 are provided in the same layer in an insulated state.

[0017] As described above, the common wiring 11 is disposed at a position that cuts through the plurality of LED chips 20 that are arrayed in the first direction, and is connected to the two n-type electrodes 24 of the plurality of LED chips 20. As a result, a conduction path in the first direction is formed in such a manner that the following connection relationship is repeated in the first direction: common wiring 11 → one n-type electrode 24 of the LED chip 20 → n-type semiconductor layer 22 of the LED chip 20 → other n-type electrode 24 of the LED chip 20 → common wiring 11 → ...

[0018] On the other hand, the segment wiring 12 is arranged at a position that cuts through the plurality of LED chips 20 arranged in an array in the second direction, and is connected to the p-type electrode 25 of one of the plurality of LED chips 20. As a result, a conduction path in the second direction is formed in such a manner that the connection relationship of segment wiring 12 → p-type electrode 25 of LED chip 20 → segment wiring 12 → ... is repeated in the second direction.

[0019] According to the matrix LED display of this embodiment configured as described above, by utilizing the vertical structure of the pn junction of the LED chip 20, a conduction path in a first direction formed by connecting the n-type electrode 24 and the common wiring 11 and a conduction path in a second direction formed by connecting the p-type electrode 25 and the segment wiring 12 intersect at an intersection within the LED chip 20, so that the common wiring 11 and the segment wiring 12 do not intersect on the wiring substrate 10. This makes it possible to configure a matrix LED display using a single wiring substrate 10.

[0020] In the above embodiment, the LED chip 20 is a monochromatic light-emitting chip, and one p-type electrode 25 is provided between two n-type electrodes 24 to emit monochromatic light, but the present invention is not limited to this. For example, as shown in Fig. 3, this embodiment can also be applied to a matrix LED display using a multicolor light-emitting LED chip 20A in which multiple p-type electrodes 25 are provided between two n-type electrodes 24 to emit multiple colors.

[0021] In the example shown in FIG. 3, three p-type electrodes 25 are provided corresponding to the three colors of red, green, and blue light. -R ,twenty five -G ,twenty five -B is provided between the two n-type electrodes 24. The segment wiring 12 is provided corresponding to each of the multiple colors, and the segment wiring 12 for each color -R ,12 -G ,12 -B 25 p-type electrodes for each color -R ,twenty five -G ,twenty five -BThe common wiring 11 and the two n-type electrodes 24 are connected in the same manner as in FIG.

[0022] In the above embodiment, the n-type electrode 24 and the p-type electrode 25 of the LED chip 20 are provided on the same layer as shown in FIG. 2 , but the present invention is not limited to this. For example, as in the LED chip 20B shown in FIG. 4 or the LED chip 20C shown in FIG. 5 , the n-type electrodes 24, 24′ and the p-type electrode 25 may be provided on different layers in an insulated state. In this case, the common wiring 11 of the wiring substrate 10 and the n-type electrodes 24, 24′ of the LED chips 20A, 20B are connected by wire bonding or the like. The configuration shown in FIG. 2 is preferable to the configurations shown in FIGS. 4 and 5 because it does not require wire bonding.

[0023] 5 shows an example of a vertical LED chip configuration in which the n-type electrode 24C and the p-type electrode 25 are arranged vertically. That is, the LED chip 20C is configured as a pn junction in which the n-type semiconductor layer 22 and the p-type semiconductor layer 23′ are joined entirely in a vertical structure, and the p-type electrode 25 is connected to the p-type semiconductor layer 23′, and one n-type electrode 24′ is provided on the back surface of the substrate 21.

[0024] 5, a conduction path in the first direction is formed by repeating the connection relationship of the common wiring 11 → n-type electrode 24' of the LED chip 20C → common wiring 11 → ... in the first direction. Also, a conduction path in the second direction is formed by repeating the connection relationship of the segment wiring 12 → p-type electrode 25 of the LED chip 20C → segment wiring 12 → ... in the second direction.

[0025] In the above embodiment, the p-type and n-type may be reversed.

[0026] Furthermore, the above-described embodiments are merely examples of specific embodiments for carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereby. In other words, the present invention can be carried out in various forms without departing from the gist or main characteristics thereof. [Explanation of symbols]

[0027] 10. Wiring board 11 Common wiring 12 segment wiring 20, 20A, 20B, 20C LED chips 21 PCB 22 n-type semiconductor layer 23,23' p-type semiconductor layer 24,24' n-type electrode 25 p-type electrode

Claims

1. A matrix LED display comprising a wiring substrate provided with a plurality of common wirings extending in a first direction and a plurality of segment wirings extending in a second direction perpendicular to the first direction, and a plurality of LED chips arranged in a matrix on the wiring substrate, the LED chip is configured with a pn junction in which a p-type semiconductor layer and an n-type semiconductor layer are joined in a vertical structure, and has one of a p-type electrode and an n-type electrode to which the common wiring is connected, and the other of the p-type electrode and the n-type electrode to which the segment wiring is connected, the n-type electrode and the p-type electrode being provided in an insulated state; the common wiring is disposed at a position that cuts through the plurality of LED chips that are arrayed in the first direction, and is connected to the one electrodes of the plurality of LED chips; The segment wiring is disposed at a position that cuts through the plurality of LED chips that are arrayed in the second direction, and is connected to the other electrodes of the plurality of LED chips. A matrix LED display.

2. the LED chip includes two n-type electrodes as the one electrode, the two n-type electrodes being connected to the n-type semiconductor layer, and the p-type electrode as the other electrode being connected to the p-type semiconductor layer; The two n-type electrodes are disposed on both sides of the p-type electrode.

2. The matrix LED display according to claim 1.

3. the LED chip includes two p-type electrodes as the one electrode, the two p-type electrodes being connected to the p-type semiconductor layer, and the n-type electrode as the other electrode being connected to the n-type semiconductor layer; The two p-type electrodes are disposed on both sides of the n-type electrode.

2. The matrix LED display according to claim 1.

4. 4. The matrix LED display according to claim 1, wherein the LED chip is a single-color light-emitting chip, and the other electrode is provided in a single piece corresponding to the single-color light emission.

5. the LED chip is a multi-color light-emitting chip, and the other electrode is provided in plurality to correspond to the multi-color light emission; The segment wiring is provided corresponding to each of the plurality of colors, and the segment wiring for each color is connected to the other electrode for each color, respectively.

4. The matrix LED display according to claim 1, wherein the matrix LED display is a light-emitting diode (LED) display.

6. 4. The matrix LED display according to claim 1, wherein the n-type electrode and the p-type electrode of the LED chip are provided in the same layer in an insulated state.

7. 4. The matrix LED display according to claim 1, wherein the n-type electrode and the p-type electrode of the LED chip are provided in different layers in an insulated state.

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