Transmissive LED display

Abstract

To provide a "transmissive LED display" capable of preventing light emitted when an LED is turned on from leaking to an opposite side of a transparent substrate.SOLUTION: A plurality of LEDs 15 and 25 are disposed on a first surface of a transparent substrate 1 and a second surface opposite to the first surface, an electrode 22 on the second surface is disposed in a second surface shielding region including a region shielding an optical path LP1 in a direction from the LED 15 disposed on the first surface toward the transparent substrate 1, and an electrode 12 on the first surface is disposed in a first surface shielding region including a region shielding an optical path LP2 in a direction from the LED 25 disposed on the second surface toward the transparent substrate 1. Thereby, light emitted in a direction from a back surface of the LED 15 on the first surface toward the transparent substrate 1 is blocked by the electrode 22 on the second surface, and light emitted in a direction from the back surface of the LED 25 on the second surface toward the transparent substrate 1 is blocked by the electrode 12 on the first surface.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a transmissive LED display, and is particularly suitable for use in a display in which a plurality of LEDs are arranged between a plurality of sets of electrodes arranged in an array on a transparent substrate, and a plurality of openings are provided where no electrodes are arranged, allowing light to pass through the openings. [Background technology]

[0002] Conventionally, transmissive displays have been known that differ from ordinary displays in that they allow the viewer to see through to what is behind them. Transmissive displays have multiple light sources arranged in an array on a transparent substrate, and multiple openings without electrodes are provided, allowing light to pass from the back to the front of the display through the openings. The ratio of the area of ​​the openings to the area of ​​one pixel is called the aperture ratio, and the higher the aperture ratio, the more background light can be taken in, resulting in a display that appears more transparent.

[0003] There are various types of transmissive displays, but transmissive LED displays in particular are expected to be used in a variety of applications because they can achieve a high transmittance of 70% or more. When constructing a transmissive LED display, it is preferable to use a technology called micro LED, in which LEDs used as light sources are miniaturized and arranged in an array. Displays using micro LEDs are disclosed, for example, in Patent Document 1.

[0004] However, when a transmissive LED display is constructed using micro LEDs, there is a problem in that the light emitted from the LED 100 to project information on the display surface leaks to the back side of the transparent substrate 103 through the gap between the anode electrode 101 and the cathode electrode 102, as shown in Figure 5. In a transmissive LED display, the substrate placed on the back side of the LED 100 is also made of the transparent substrate 103, so when the LED 100 is turned on, light leaks from the back side of the LED 100 to the back side of the display through the gap between the electrodes 101 and 102.

[0005] A display device is known that allows light emitted from the backside of a light-emitting element chip to be extracted to the front (see, for example, Patent Document 2). The display device described in Patent Document 2 has an LED chip on a circuit board, and the wiring pattern of the circuit board is made of a light-reflective material, such as aluminum. By using a part of the light-reflective wiring pattern as a chip-mounting layer and directly mounting a light-emitting element chip on this chip-mounting layer, it is possible to extract light emitted from the backside of the light-emitting element chip to the front with a simple configuration. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-52156 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-204370 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made to solve the above-mentioned problems, and aims to prevent light emitted when an LED is turned on from leaking to the opposite side of the transparent substrate in a transmissive LED display. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the present invention provides a transmissive LED display in which a plurality of LEDs are arranged between a plurality of sets of electrodes arranged in an array on a transparent substrate, and a plurality of openings on the transparent substrate where no electrodes are arranged are provided, thereby allowing light to pass through the plurality of openings.A plurality of LEDs are arranged on a first surface of the transparent substrate and a second surface opposite the first surface, and an electrode on the second surface is arranged in a second surface shielding area that includes an area that shields the optical path from the LEDs arranged on the first surface toward the transparent substrate, and an electrode on the first surface is arranged in a first surface shielding area that includes an area that shields the optical path from the LEDs arranged on the second surface toward the transparent substrate. [Effects of the Invention]

[0009] According to the present invention configured as described above, in a transmissive LED display, when the LEDs on the first surface are turned on, the light irradiated from the back surface of the LEDs on the first surface toward the transparent substrate is blocked by the electrode on the second surface, and when the LEDs on the second surface are turned on, the light irradiated from the back surface of the LEDs on the second surface toward the transparent substrate is blocked by the electrode on the first surface, thereby preventing the light irradiated by the LEDs from leaking to the opposite surface of the transparent substrate. [Brief explanation of the drawings]

[0010] [Figure 1] 1A and 1B are diagrams illustrating an example of an LED arrangement in a transmissive LED display according to an embodiment of the present invention. [Figure 2] 1 is a diagram showing an example of a cross-sectional configuration of an LED arrangement structure of a transmissive LED display according to an embodiment of the present invention. [Figure 3] 10 is a diagram showing another example of a cross-sectional configuration of the LED arrangement structure of the transmissive LED display according to the present embodiment. FIG. [Figure 4] 10 is a diagram showing another example of a cross-sectional configuration of the LED arrangement structure of the transmissive LED display according to the present embodiment. FIG. [Figure 5] 1A and 1B are diagrams showing the structure of a light-emitting part of a transmissive LED display. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment of the present invention will be described below with reference to the drawings. Figures 1 and 2 are diagrams showing an example of an LED arrangement structure of a transmissive LED display according to this embodiment. Figure 1 schematically shows the LED arrangement structure of the transmissive LED display as viewed from above (the side of the first surface described below) of a transparent substrate 1. As an example, this embodiment shows an example of the configuration of a transmissive LED display using micro LED elements.

[0012] 1, the transmissive LED display of this embodiment is a display in which a plurality of LEDs 15 are arranged between a plurality of sets of electrodes (not shown) arranged in an array on a transparent substrate 1, and a plurality of openings 30 where no electrodes are arranged are provided on the transparent substrate 1, thereby allowing light to pass through the openings 30. This allows background light to pass through from behind the display to the front side, allowing the background of the display to be seen through from the front side.

[0013] In the LED arrangement shown in Fig. 1, one pixel 10 is composed of three subpixels (shown as 10R, 10G, and 10B in Fig. 2) each having an LED 15 (red LED, green LED, and blue LED) for each of RGB. An opening 30 is formed between adjacent subpixels 10R, 10G, and 10B and between adjacent pixels 10. Note that while an example of a configuration with subpixels in which three RGB LEDs 15 are arranged in one pixel 10 is shown here, a configuration without subpixels in which one LED 15 is arranged in one pixel may also be used.

[0014] 2 is a diagram showing an example of a cross-sectional configuration of the LED arrangement structure of this embodiment when viewed from the side, in which the upper part of the figure shows the first surface of the transparent substrate 1, and the lower part of the figure shows the second surface of the transparent substrate 1 opposite to the first surface.

[0015] As shown in Fig. 2, in the transmissive LED display of this embodiment, a plurality of LEDs 15, 25 are arranged on the first and second surfaces of a transparent substrate 1, respectively. Fig. 2 shows the LED arrangement structure of one pixel. On the first surface, one pixel includes a plurality of subpixels 10R, 10G, 10B corresponding to red, green, and blue light emission, and an LED 15 is arranged for each of the subpixels 10R, 10G, 10B. Similarly, on the second surface, one pixel includes a plurality of subpixels 20R, 20G, 20B, and an LED 25 is arranged for each of the subpixels 20R, 20G, 20B.

[0016] Each of the subpixels 10R, 10G, and 10B on the first surface has a pair of anode electrode 11 and cathode electrode 12 arranged at a predetermined interval on the transparent substrate 1, and an LED 15 is arranged between and electrically connected to the electrodes 11 and 12. In the example of Fig. 2, the LED 15 is mounted via a bump 14 on a bonding material 13 formed on the electrodes 11 and 12. An opening 30 where the electrodes 11 and 12 are not arranged is provided between adjacent subpixels 10R, 10G, and 10B.

[0017] The second surface of the transparent substrate 1 is configured in the same manner as the first surface. That is, for each of the subpixels 20R, 20G, and 20B on the second surface, a pair of an anode electrode 21 and a cathode electrode 22 is arranged at a predetermined interval on the transparent substrate 1, and an LED 25 is arranged between and electrically connected to the electrodes 21 and 22. In the example of Fig. 2, the LED 25 is mounted via a bump 24 on a bonding material 23 formed on the electrodes 21 and 22. An opening 40 where the electrodes 21 and 22 are not arranged is provided between adjacent subpixels 20R, 20G, and 20B.

[0018] In this embodiment, the cathode electrode 22 on the second surface is arranged in the second surface shielding area including an area that shields the optical path LP1 (indicated by the dotted arrow) in the direction from the back of the LED 15 arranged on the first surface toward the transparent substrate 1, and the cathode electrode 12 on the first surface is arranged in the first surface shielding area including an area that shields the optical path LP2 (indicated by the dotted arrow) in the direction from the back of the LED 25 arranged on the second surface toward the transparent substrate 1.

[0019] That is, the cathode electrodes 12 (corresponding to one electrode in the claims) of each of the subpixels 10R, 10G, and 10B on the first surface are arranged in the first surface shielding region facing the corresponding subpixels 20R, 20G, and 20B on the second surface, and the cathode electrodes 22 (one electrode) of each of the subpixels 20R, 20G, and 20B on the second surface are arranged in the second surface shielding region facing the corresponding subpixels 10R, 10G, and 10B on the first surface.

[0020] The second-surface shielding region including the region blocking the optical path LP1 means that it is sufficient to include at least the region blocking the optical path LP1 (the region of the second surface facing the region of the first surface blocking the gap between the electrodes 11 and 12), and may be an area the same size as the region blocking the optical path LP1, or a larger area. Similarly, the first-surface shielding region including the region blocking the optical path LP2 means that it is sufficient to include at least the region blocking the optical path LP2 (the region of the first surface facing the region of the second surface blocking the gap between the electrodes 21 and 22), and may be an area the same size as the region blocking the optical path LP2, or a larger area. Figure 2 shows an example in which the first-surface shielding region and the second-surface shielding region are regions the same size as the regions blocking the optical paths LP1 and LP2.

[0021] With this LED arrangement structure, when the LEDs 15 on the first surface are turned on, light along optical path LP1 that is emitted from the back surface of the LEDs 15 on the first surface in a direction toward the transparent substrate 1 is blocked by the cathode electrode 22 on the second surface. Furthermore, when the LEDs 25 on the second surface are turned on, light along optical path LP2 that is emitted from the back surface of the LEDs 25 on the second surface in a direction toward the transparent substrate 1 is blocked by the cathode electrode 12 on the first surface. This makes it possible to prevent the light emitted by the LEDs 15, 25 from leaking to the opposite surface of the transparent substrate 1.

[0022] The anode electrodes 11 (corresponding to the other electrodes in the claims) of the sub-pixels 10R, 10G, and 10B on the first surface are arranged in a first surface region including an area not facing the sub-pixels 20R, 20G, and 20B on the second surface (an area facing the openings 40 on the second surface). The anode electrodes 21 (the other electrodes) of the sub-pixels 20R, 20G, and 20B on the second surface are arranged in a first surface region including an area not facing the sub-pixels 10R, 10G, and 10B on the first surface (an area facing the openings 30 on the first surface).

[0023] 2, the first surface region on the first surface where the anode electrode 11 is arranged is a region including a region facing the entire region of the openings 40 formed between the sub-pixels 20R, 20G, and 20B on the second surface. Also, the second surface region on the second surface where the anode electrode 21 is arranged is a region including a region facing the entire region of the openings 30 formed between the sub-pixels 10R, 10G, and 10B on the first surface.

[0024] The first surface region including the region facing the entire region of opening 40 means that it is sufficient to include at least the region facing the entire region of opening 40, and may be a region the same size as that region or a larger region. Similarly, the second surface region including the region facing the entire region of opening 30 means that it is sufficient to include at least the region facing the entire region of opening 30, and may be a region the same size as that region or a larger region. Figure 2 shows an example in which the first surface region and the second surface region are regions the same size as the region facing the entire regions of openings 30 and 40.

[0025] With this configuration, when the LEDs 15 on the first surface are turned on, light that may leak out of the subpixels 10R, 10G, and 10B from the back surface of the LEDs 15 on the first surface is blocked by the anode electrode 21 on the second surface. Furthermore, when the LEDs 25 on the second surface are turned on, light that may leak out of the subpixels 20R, 20G, and 20B from the back surface of the LEDs 25 on the second surface is blocked by the anode electrode 11 on the first surface. This makes it possible to more effectively prevent the light emitted by the LEDs 15 and 25 from leaking to the opposite surface of the transparent substrate 1.

[0026] 3, the first surface region on the first surface where the anode electrode 11 is disposed may be configured to face a partial region of the opening 40 on the second surface, and the second surface region on the second surface where the anode electrode 21 is disposed may be configured to face a partial region of the opening 30 on the first surface. This configuration can increase the aperture ratio of the transmissive LED display and enhance transparency while preventing, to some extent, light that may leak out of the subpixels 10R, 10G, 10B, 20R, 20G, and 20B from the rear surfaces of the LEDs 15 and 25 to the opposite surface of the transparent substrate 1. FIG. 3 shows an example in which the first surface shielding region and the second surface shielding region are larger than the regions shielding the light paths LP1 and LP2 (an example in which the cathode electrodes 12 and 22 are larger than the regions shielding the light paths LP1 and LP2).

[0027] The electrodes arranged in the first surface shielding region and the second surface shielding region may be configured in the opposite manner to the above embodiment. That is, the anode electrode 11 on the first surface may be arranged in the first surface shielding region facing the subpixels 20R, 20G, and 20B on the second surface, and the cathode electrode 12 may be arranged in the first surface region including the region not facing the subpixels 20R, 20G, and 20B on the second surface, while the anode electrode 21 on the second surface may be arranged in the first surface shielding region facing the subpixels 10R, 10G, and 10B on the first surface, and the cathode electrode 22 may be arranged in the second surface region including the region not facing the subpixels 10R, 10G, and 10B on the first surface.

[0028] 4, a reflective material 16 having optical reflectivity may be arranged between each pair of electrodes 11, 12 on the first surface, and a reflective material 26 may be arranged between each pair of electrodes 21, 22 on the second surface. Fig. 4 shows a configuration example in which a reflective material 16 is arranged in the area that fills the gap between electrodes 11, 12 on the first surface, and a reflective material 26 is arranged in the area that fills the gap between electrodes 21, 22 on the second surface. Note that it is not essential to arrange the reflective materials 16, 26 in the areas that completely fill the gap.

[0029] 4, the light along optical path LP1 emitted from the back surface of LED 15 on the first surface toward transparent substrate 1 is reflected toward the information display surface of the first surface, and the light along optical path LP2 emitted from the back surface of LED 25 on the second surface toward transparent substrate 1 is reflected toward the information display surface of the second surface, thereby improving light utilization efficiency. In addition, light that may otherwise pass through the reflectors 16, 26 can be blocked by the cathode electrodes 12, 22 on the first and second surfaces.

[0030] In addition, although the above embodiment describes the configuration of a transmissive LED display using micro LED elements, the present invention is not limited to this. That is, the LED arrangement structure of this embodiment can be applied to a transmissive LED display having a structure in which LED light leaks through the gap between the electrodes.

[0031] 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]

[0032] 1 Transparent substrate 11,21 Anode electrode 12,22 Cathode electrode 15,25 LED 16,26 Reflective material 10R, 10G, 10B Subpixels on the first surface 20R, 20G, 20B Second surface subpixel 30 First side opening 40 Second side opening

Claims

1. A transmissive LED display has a plurality of LEDs arranged between a plurality of sets of electrodes arranged in an array on a transparent substrate, and a plurality of openings on the transparent substrate where no electrodes are arranged, thereby allowing light to pass through the openings, A transmissive LED display characterized in that the plurality of LEDs are arranged on a first surface of the transparent substrate and on a second surface opposite the first surface, respectively, and the electrodes on the second surface are arranged in a second surface shielding area including an area that shields the optical path from the LEDs arranged on the first surface toward the transparent substrate, and the electrodes on the first surface are arranged in a first surface shielding area including an area that shields the optical path from the LEDs arranged on the second surface toward the transparent substrate.

2. 2. The transmissive LED display according to claim 1, wherein a reflective material having optical reflectivity is disposed between each pair of electrodes on the first surface, and the reflective material is disposed between each pair of electrodes on the second surface.

3. One pixel includes a plurality of sub-pixels, and the LED is disposed for each of the sub-pixels; For each pair of electrodes disposed on the first surface, one electrode is disposed in the first surface shielding region facing the subpixels of the second surface, and the other electrode is disposed in a first surface region including a region not facing the subpixels of the second surface; For each pair of electrodes arranged on the second surface, one electrode is arranged in the second surface shielding region facing the subpixels of the first surface, and the other electrode is arranged in the second surface region including a region not facing the subpixels of the first surface.

3. The transmissive LED display according to claim 1 or 2.

4. the first surface region in which the other electrode is arranged on the first surface includes a region facing the entire region of the opening formed between the subpixels on the second surface, The second surface region in which the other electrode is arranged on the second surface is a region including a region facing the entire region of the opening formed between the subpixels on the first surface.

4. The transmissive LED display according to claim 3.

5. the first surface region in which the other electrode is arranged on the first surface is a region facing a partial region of the opening portion formed between subpixels on the second surface, The second surface region in which the other electrode is arranged on the second surface is a region facing a partial region of the opening formed between the subpixels on the first surface.

4. The transmissive LED display according to claim 3.

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