WO2021079424A1

WO2021079424A1 - Image display device

Info

Publication number: WO2021079424A1
Application number: PCT/JP2019/041459
Authority: WO
Inventors: 智彦澤中; 村井　偉志
Original assignee: 三菱電機株式会社
Priority date: 2019-10-23
Filing date: 2019-10-23
Publication date: 2021-04-29

Abstract

Provided is an image display device (100) comprising a substrate (10) that has a main surface (10a), and a holding case (6) that holds the substrate (10). A plurality of LEDs (8) and protruding parts (9) are provided to the main surface (10a) of the substrate (10). A protective panel (7) covers the plurality of LEDs (8) and the protruding parts (9). The protruding parts (9) are configured so that the protective panel (7) does not come into contact with the plurality of LEDs (8).

Description

Video display device

The present invention relates to an image display device that displays an image using a light emitting element.

In recent years, home-use televisions that display high-resolution images called 4K or 8K have been released. In order to display high-resolution video with high quality, a video display device with a large screen size is required. Therefore, the size of the video display device is increasing. In addition, as information terminals, large-scale video display devices are increasingly installed in public places, and there is an increasing need for larger-sized video display devices.

For example, Patent Document 1 discloses a configuration using a self-luminous organic light emitting element (hereinafter, also referred to as “related configuration A”). In the related configuration A, the size of the display device is increased by arranging a plurality of element substrates on which the organic light emitting element is mounted.

Japanese Patent No. 4059153

In the related configuration A, the organic light emitting element as the light emitting element is in close contact with the sealing substrate which is the protective panel via the protective film, the adhesive layer and the like. Therefore, in the related configuration A, when a pressure is applied to the sealing substrate which is a protective panel, the pressure is transmitted to the organic light emitting element, and there is a problem that the organic light emitting element may be damaged.

Therefore, it is required that the light emitting element is not in close contact with the protective panel.

The present invention has been made to solve such a problem, and an object of the present invention is to provide an image display device in which a light emitting element is not in close contact with a protective panel.

In order to achieve the above object, the image display device according to one aspect of the present invention displays images. The image display device includes a substrate having a main surface which is a surface on the viewing side and a holding housing for holding the substrate, and a plurality of LEDs (Lights) for expressing the image are provided on the main surface of the substrate. (Emitting Diode) and a convex portion are provided, and the image display device further includes the plurality of LEDs and a protective panel covering the convex portion, and the convex portion protects the convex portion from the main surface. The convex portion is configured so as to extend toward the panel and prevent the protective panel from contacting the plurality of LEDs.

According to the present invention, a plurality of LEDs and a convex portion are provided on the main surface of the substrate. The protective panel covers the plurality of LEDs and the convex portion. The convex portion is configured so that the protective panel does not come into contact with the plurality of LEDs.

This makes it possible to provide an image display device in which each LED as a light emitting element is not in close contact with the protective panel.

The purpose, features, aspects, and advantages of the present invention will be made clearer by the following detailed description and accompanying drawings.

It is an external view of the image display device which concerns on Embodiment 1. FIG. It is sectional drawing of the panel part which concerns on Embodiment 1. FIG. It is an enlarged view of a part of the panel part which concerns on Embodiment 1. FIG. It is an enlarged view of the area where the electric wiring is provided in the substrate. It is a figure for demonstrating how the light emitted from an LED travels. It is sectional drawing of the panel part which has the structure of the modification 1. FIG. It is an enlarged view of a part of the panel part which has the structure of the modification 1. It is an enlarged view of the area where the electric wiring is provided in the substrate which has the structure of the modification 1. It is a figure for demonstrating the way of advancing the light emitted from the LED in the modification 1.

Hereinafter, embodiments will be described with reference to the drawings. In the drawings below, the same components are designated by the same reference numerals. The names and functions of the components with the same reference numerals are the same. Therefore, detailed description of some of the components having the same reference numerals may be omitted.

The dimensions, materials, shapes, relative arrangements, and the like of the components exemplified in the embodiment may be appropriately changed depending on the configuration of the device, various conditions, and the like. In addition, the dimensions of the components in the figure may differ from the actual dimensions.

<Embodiment 1>
FIG. 1 is an external view of the video display device 100 according to the first embodiment. The image display device 100 is a device that displays an image. Note that FIG. 1 shows the coordinate axes of the xyz Cartesian coordinate system for ease of explanation.

In FIG. 1, the x-direction, the y-direction, and the z-direction are orthogonal to each other. The x, y, and z directions shown in the figure below are also orthogonal to each other. In the following, the direction including the x direction and the direction opposite to the x direction (−x direction) is also referred to as “x-axis direction”. Further, in the following, the direction including the y direction and the direction opposite to the y direction (−y direction) is also referred to as “y-axis direction”. Further, in the following, the direction including the z direction and the direction opposite to the z direction (−z direction) is also referred to as “z axis direction”.

Further, in the following, a plane including the x-axis direction and the y-axis direction is also referred to as an “xy plane”. Further, in the following, a plane including the x-axis direction and the z-axis direction is also referred to as an “xz plane”. Further, in the following, a plane including the y-axis direction and the z-axis direction is also referred to as a “yz plane”.

With reference to FIG. 1, the image display device 100 includes a panel portion 50, a bezel 2, a design housing 3, and a stand 4. The panel unit 50 has a function of displaying an image. The bezel 2 holds the panel portion 50. The design housing 3 covers the back surface portion of the panel portion 50. The stand 4 supports the bezel 2 that holds the panel portion 50 and the design housing 3.

The x-axis direction corresponds to the horizontal direction of the image display device 100. The y-axis direction corresponds to the vertical direction of the image display device 100. The z-axis direction corresponds to the depth direction of the image display device 100. The x direction included in the x-axis direction corresponds to the right direction included in the horizontal direction in the panel portion 50. The −x direction included in the x-axis direction corresponds to the left direction included in the horizontal direction in the panel portion 50.

Further, the y direction included in the y-axis direction corresponds to the upward direction included in the vertical direction in the panel portion 50. Further, the −y direction included in the y-axis direction corresponds to the downward direction included in the vertical direction in the panel portion 50. Further, the z direction included in the z-axis direction corresponds to the direction from the back surface of the image display device 100 toward the panel unit 50. Further, the −z direction included in the z-axis direction corresponds to a direction from the front surface of the panel portion 50 of the image display device 100 toward the back surface of the design housing 3.

FIG. 2 is a cross-sectional view of the panel portion 50 according to the first embodiment. FIG. 3 is an enlarged view of a part of the panel portion 50 according to the first embodiment. With reference to FIGS. 2 and 3, the panel unit 50 includes a holding housing 6, a plurality of video display boards 5, and a protective panel 7. The back surface 6b of the holding housing 6, which will be described later, is covered with the design housing 3 of FIG. The holding housing 6, the plurality of video display boards 5, and the protective panel 7 are arranged in the order of the holding housing 6, the plurality of video display boards 5, and the protective panel 7 from the design housing 3 side in the z direction. It is arranged in.

Each image display board 5 is the board 10 provided with a plurality of LEDs (Light Emitting Diodes 8) and a plurality of convex portions 9 on the board 10. The substrate 10 has a main surface 10a and a back surface 10b. The main surface 10a is a surface on the viewing side. The surface on the viewing side is a surface to be visually recognized by the user. Specifically, a plurality of LEDs 8 and a plurality of convex portions 9 are provided on the main surface 10a of the substrate 10.

In the following, red, green and blue are also referred to as R, G and B, respectively. Further, in the following, red light, green light and blue light are also referred to as R light, G light and B light, respectively.

The plurality of LEDs 8 are LEDs that express images. Each LED 8 is an LED chip for expressing one pixel in an image. The pixels represented by each LED 8 are different. Each LED 8 is, for example, a micro LED. Each LED 8 may be a mini-LED.

Each LED 8 includes three LED elements (not shown). The three LED elements can emit R light, G light, and B light, respectively. The three LED elements represent three sub-pixels in one pixel.

In the following, the length of one side of the light emitting portion of the LED element, which is one subpixel included in one LED, is also referred to as "light emitting portion length". A micro LED is an LED having a light emitting portion having a length in the range of, for example, several μm to about 30 μm. By arranging a plurality of micro LEDs in a matrix, it is possible to realize a video display device having the following merits.

The merit is that, for example, it is more environmentally resistant than a video display device using an organic light emitting element. Further, the merit is that, for example, it is possible to output a high-brightness image as compared with an image display device using an organic light emitting element. Further, the merit is that the power consumption is smaller than that of, for example, an image display device using an organic light emitting element.

In recent years, as LEDs for televisions, micro LEDs having a light emitting portion length in the range of 10 μm to about 30 μm have been developed. Further, as an LED for a smart watch, a micro LED having a light emitting portion length of several μm has been developed.

Also, the mini-LED is a larger LED than the micro LED. In the following, a value larger than the upper limit value of the light emitting portion length of the micro LED is also referred to as “value v”. An LED having a light emitting portion length in a range of, for example, about 800 μm from the minimum value of the value v is a mini-LED. Mini-LEDs are used, for example, in public signage.

The video display device 100 includes an electrical unit (not shown) and an input / output unit (not shown). The electrical unit and the input / output unit are housed in the design housing 3. The electric unit has a function of controlling the panel unit 50. The input / output unit has a function of inputting / outputting a signal to the outside.

In the video display device 100, the electrical unit sends a control signal to the panel unit 50 based on the signal input to the input / output unit. The panel unit 50 controls switching between lighting and extinguishing of each of the plurality of LEDs 8 based on the control signal. As a result, the panel unit 50 displays the image.

Further, the plurality of video display boards 5 are arranged so as not to overlap each other. The holding housing 6 holds a plurality of boards 10 as the image display board 5. The holding housing 6 is made of a non-transparent material. Specifically, the holding housing 6 has a main surface 6a and a back surface 6b. The main surface 6a is a flat surface. A plurality of video display boards 5 are arranged on the main surface 6a of the holding housing 6. That is, the plurality of image display boards 5 (boards 10) are arranged along a specific direction which is a direction parallel to the main surface 6a. The plurality of image display boards 5 are fixed to the main surface 6a with an adhesive (not shown).

Note that, in FIG. 2, as an example, two video display boards 5 arranged along the y-axis direction are shown, but the number of video display boards 5 is not limited to two. The number of the image display boards 5 may be 3 or more. Further, the plurality of video display boards 5 may be arranged not only in the y-axis direction but also in the x-axis direction. For example, the plurality of video display boards 5 may be arranged in a matrix along the xy plane.

Further, the holding housing 6 has a function of dissipating the heat generated by the LED 8. The holding housing 6 is made of, for example, sheet metal, glass, or the like.

The protective panel 7 is a transparent plate-shaped member. The protective panel 7 is made of resin or glass. The protective panel 7 has flexibility. The protective panel 7 does not have to be flexible. The protective panel 7 is held by a housing (not shown) of the panel portion 50. The housing of the panel portion 50 is a member that forms the outer surface of the panel portion 50. The protective panel 7 may be held by the bezel 2.

The protective panel 7 protects the plurality of LEDs 8 so that the user cannot directly touch the plurality of LEDs 8. Specifically, the protective panel 7 faces the main surface 10a of the plurality of substrates 10. That is, the protective panel 7 covers the plurality of LEDs 8 and the plurality of convex portions 9.

The shape of the convex portion 9 is columnar and long. One of the two ends of the convex portion 9 in the longitudinal direction of the convex portion 9 is fixed to the main surface 10a of the substrate 10 by a transparent adhesive. Therefore, the convex portion 9 extends from the main surface 10a toward the protective panel 7.

The convex portion 9 has translucency. Specifically, the convex portion 9 is made of a transparent resin so that it is difficult to see. That is, the convex portion 9 is transparent. The transparent resin is an acrylic resin such as PMMA (Polymethyl methyllate), a silicone resin, or the like. The convex portion 9 is not limited to being transparent as long as it has translucency.

Further, the refractive index of the convex portion 9 is the same as or equivalent to the refractive index of the protective panel 7. In the present specification, the "refractive index" is the "refractive index of light".

In the following, the state in which the protective panel 7 is bent so that a part of the protective panel 7 approaches the plurality of LEDs 8 is also referred to as a “deflection state”. The bending state protective panel 7 is, for example, the protective panel 7 in a state in which the protective panel 7 is bent by an external force. Further, in the following, the state of the protective panel 7 in a state where the protective panel 7 is not deformed is also referred to as a “normal state”.

In a situation where the protective panel 7 is in a normal state, the light emitting portion of each LED 8 is not in direct or indirect contact with the protective panel 7. The light emitting portion of each LED 8 is a portion of the LED 8 from which light is emitted. Further, the light emitting portion of each LED 8 is a portion of the LED 8 facing the protective panel 7.

Further, the convex portion 9 is configured so that the protective panel 7 does not come into contact with the light emitting portions of the plurality of LEDs 8. That is, the convex portion 9 is configured so that the protective panel 7 does not come into contact with the plurality of LEDs 8. For example, the convex portion 9 is configured so that the protective panel 7 does not come into contact with the plurality of LEDs 8 even if the state of the protective panel 7 shifts from the normal state to the flexed state.

Specifically, the height of the convex portion 9 is higher than the height of each LED 8. The height of the convex portion 9 is k times the height of each LED 8. "K" is a positive real number. “K” is, for example, a value included in the range of 1.1 to 10. Further, even if the state of the protective panel 7 shifts from the normal state to the flexed state, the protective panel 7 contacts a part or all of the plurality of convex portions 9, and the protective panel 7 does not contact the plurality of LEDs 8. As described above, the plurality of convex portions 9 are provided on the main surface 10a.

Further, as described above, the protective panel 7 does not have to have flexibility. Here, it is assumed that an external force is applied to the protective panel 7 so that the inflexible protective panel 7 approaches the plurality of LEDs 8. In this case, when the height of the convex portion 9 is higher than the height of each LED 8, the inflexible protective panel 7 contacts the convex portion 9, and the protective panel 7 contacts the plurality of LEDs 8. do not.

Further, the convex portion 9 is not in contact with the protective panel 7 in the normal state.

Note that there is a joint 11 which is a boundary between the two adjacent boards 10 as the image display board 5. In FIGS. 2 and 3, the joint 11 extends in the x-axis direction. The two adjacent substrates 10 are included in a plurality of substrates 10 included in the panel portion 50. An adhesive portion 12 is provided on the main surface 10a of each of the two adjacent substrates 10. The adhesive portion 12 is an adhesive. The adhesive portion 12 is provided so that the adhesive portion 12 covers the joint 11. Specifically, the adhesive portion 12 covers the joint 11 along the extending direction of the joint 11. As a result, the two adjacent substrates 10 are fixed.

Further, as shown in FIGS. 2 and 3, the color of the main surface 10a of the substrate 10 is black. Specifically, the main surface 10a side of the substrate 10 is colored black. Due to the coloring of black, when the LED 8 is turned off, the periphery of the turned off LED 8 becomes darker. As a result, the contrast of the image displayed by the panel unit 50 is improved.

Further, the color of the adhesive portion 12 is the same as the color of the main surface 10a of each of the two adjacent substrates 10. Specifically, the color of the adhesive portion 12 is the same as the color of the main surface 10a of each of the two adjacent substrates 10. The color of the adhesive portion 12 is, for example, black. As a result, the joint 11 covered by the adhesive portion 12 can be made inconspicuous. The expression "the color of the adhesive portion 12 is the same as the color of the main surface 10a" also includes the meaning that the color of the adhesive portion 12 is the same as the color of the main surface 10a.

Also, the color of the main surface 10a is not limited to black. The color of the main surface 10a may be a color close to black (for example, gray). In this case, the color of the adhesive portion 12 may be the color of the main surface 10a (that is, a color close to black). As a result, the joint 11 can be made inconspicuous.

Further, electrical wiring 13 is provided at least at one place on the board 10 as each video display board 5. FIG. 4 is an enlarged view of a region of the substrate 10 where the electrical wiring 13 is provided. In FIG. 4, black, which is the color of the adhesive portion 12, is represented by a light color in order to make it easier to see one end side of the electrical wiring 13.

With reference to FIG. 4, the electrical wiring 13 is a signal line for driving the LED 8. One end of the electrical wiring 13 is connected to the substrate 10. The other end of the electrical wiring 13 is connected to an electrical section (not shown). The plurality of LEDs 8 mounted on the substrate 10 are connected to each other by printed wiring (not shown) printed on the main surface 10a of the substrate 10. One end of the electrical wiring 13 is connected to the printed wiring to which each LED 8 is connected.

Further, the holding housing 6 is provided with a wiring hole 14. The wiring hole 14 is provided in a region corresponding to the position of the joint 11. The other end of the electric wiring 13 is connected to an electric portion (not shown) existing on the back surface 6b side of the holding housing 6 via a wiring hole 14.

The color of the electrical wiring 13 is often different from the color (black) of the main surface 10a of the substrate 10. Therefore, the electrical wiring 13 is easily visible from the outside of the panel portion 50. Further, the joint portion between the electrical wiring 13 and the substrate 10 is very fragile.

Therefore, the adhesive portion 12 is provided at the joint portion between the electric wiring 13 and the substrate 10 so that the adhesive portion 12 covers one end side of the electric wiring 13. As a result, the electric wiring 13 is fixed to the substrate 10, and the electric wiring 13 is hard to be visually recognized from the outside of the panel portion 50.

Next, how the light emitted from the LED 8 travels will be described. In the following, the light emitted from the LED 8 toward the protective panel 7 is also referred to as “light L1”. FIG. 5 is a diagram for explaining how the light L1 emitted from the LED 8 travels. The color of the main surface 10a is black, and the main surface 10a absorbs light. Therefore, in FIG. 5, only the light L1 emitted from the LED 8 toward the protective panel 7 is shown.

Light L1 propagates along the yz plane as an example. In the following, the two substances in contact with each other are also referred to as substances A and B, respectively. It is assumed that the refractive indexes of substances A and B are different.

According to Fresnel's equation, light has the following properties a, b, c, d. Property a is a property that when light is irradiated to the interface between substances A and B, a part of the light is reflected at the interface. Further, the property b is that when the interface between the substances A and B is irradiated with light, another part of the light is refracted at the interface and passes through the inside of either the substance A or B. is there.

Further, the property c is a property that the larger the difference in the refractive indexes of the substances A and B, the easier it is for light to be reflected. The property d is that light easily propagates to a substance having a high refractive index among the substances A and B.

In the following, the configuration in which the convex portion 9 does not exist on the lateral side of the LED 8 is also referred to as “comparative configuration Na”. The comparative configuration Na has a configuration different from that of the present embodiment. FIG. 5A is a diagram for explaining how light travels in the comparative configuration Na.

In the comparative configuration Na, the light L1 first reaches the protective panel 7. The refractive index of the protective panel 7 is larger than the refractive index of air. Therefore, most of the light L1 propagates inside the protective panel 7, and another part of the light L1 is reflected by the protective panel 7.

In the following, the angle formed by the direction in which the light L1 propagates and the z-axis direction is also referred to as the “light L1 angle”. According to Snell's law, in the region of the protective panel 7 where the light L1 is irradiated, the larger the light L1 angle, the more the light component reflected by the protective panel 7.

In the following, the configuration of the first embodiment is also referred to as “configuration A”. In the configuration A, the convex portion 9 exists on the lateral side of the LED 8. Further, in the configuration A, the convex portion 9 is not in contact with the protective panel 7.

FIG. 5B is a diagram for explaining how light travels in the configuration of the present embodiment. In the configuration A, the light L1 first reaches the protective panel 7. In the configuration A, a thin air layer exists between the convex portion 9 and the protective panel 7. Therefore, as in FIG. 5A, most of the light L1 propagates inside the protective panel 7, and another part of the light L1 is reflected by the protective panel 7.

In the following, the configuration in which the convex portion 9 exists on the lateral side of the LED 8 and the convex portion 9 is in contact with the protective panel 7 is also referred to as “comparative configuration Nb”. The comparative configuration Nb has a configuration different from that of the present embodiment. FIG. 5C is a diagram for explaining how light travels in the comparative configuration Nb.

In the comparative configuration Nb, there is no thin air layer between the convex portion 9 and the protective panel 7. Therefore, in the comparative configuration Nb, the light L1 first reaches the convex portion 9. In this case, most of the light L1 propagates inside the convex portion 9, and another part of the light L1 is reflected by the convex portion 9.

Most of the light L1 propagating inside the convex portion 9 reaches the protective panel 7. There is almost no difference between the refractive index of the convex portion 9 and the refractive index of the protective panel 7. Therefore, most of the light L1 propagates inside the protective panel 7.

In the following, in the comparative configuration Nb, another part of the light L1 reflected by the convex portion 9 is also referred to as “convex reflected light”. The convex reflected light reaches the protective panel 7. In this case, most of the convex reflected light propagates inside the protective panel 7. Another part of the convex reflected light is reflected by the protective panel 7. At this time, the amount of light reflected by the protective panel 7 is very small. Therefore, most of the light L1, which corresponds to most of the convex reflected light, propagates inside the protective panel 7.

Therefore, in the situation where the panel portion 50 having the comparative configuration Nb displays the image, the peripheral portion of the portion where the convex portion 9 is in contact with the protective panel 7 becomes unnecessarily bright. Therefore, there is a problem that bright spots are observed. That is, the comparative configuration Nb is an unfavorable configuration. Therefore, it is necessary to prevent the convex portion 9 from directly contacting the protective panel 7.

Therefore, in the present embodiment, for example, after the adhesive for fixing the convex portion 9 is cured, the convex portion 9 is provided so that the convex portion 9 does not come into contact with the protective panel 7.

As described above, according to the present embodiment, the main surface 10a of the substrate 10 is provided with a plurality of LEDs 8 and a convex portion 9. The protective panel 7 covers the plurality of LEDs 8 and the convex portion 9. The convex portion 9 is configured so that the protective panel 7 does not come into contact with the plurality of LEDs 8.

Further, according to the present embodiment, the light emitting element for expressing the pixel is not an organic light emitting element but an LED. Further, the LED 8 as the LED is a micro LED or a mini-LED. Further, a plurality of convex portions 9 are provided on the main surface 10a of the substrate 10. As a result, in the present embodiment, it is not necessary to use a protective film, an adhesive layer, or the like as in the related configuration A described above. Therefore, the weight of the image display device 100 can be reduced. Further, by arranging a plurality of video display boards 5 side by side, it is possible to increase the size of the screen of the video display device 100. As a result, it is possible to reduce the weight of the image display device 100 and increase the size of the screen of the image display device 100.

Further, it is not necessary to bury a protective film, an adhesive layer, or the like between the substrate 10 and the protective panel 7. Therefore, the material cost and the cost of the manufacturing apparatus can be reduced.

Further, according to the present embodiment, the height of the convex portion 9 is higher than the height of each LED 8. This makes it possible to prevent the protective panel 7 from coming into contact with each LED 8.

Further, a plurality of convex portions 9 are provided on the main surface 10a of the substrate 10. As a result, it is possible to prevent the protective panel 7 from coming into contact with the LED 8 and destroying the LED 8.

Further, the convex portion 9 is not in contact with the protective panel 7. This makes it possible to prevent bright spots from appearing on the panel portion 50.

Further, an adhesive portion 12 is provided on the main surface 10a of the two adjacent substrates 10. The adhesive portion 12 is provided so that the adhesive portion 12 covers the joint 11. As a result, the two adjacent substrates 10 can be securely fixed.

Further, the adhesive portion 12 is provided at the joint portion between the electric wiring 13 and the substrate 10 so that the adhesive portion 12 covers one end side of the electric wiring 13. Therefore, the electrical wiring 13 can be securely fixed to the substrate 10.

Further, the color of the adhesive portion 12 is the same as the color of the main surface 10a of the two adjacent substrates 10. As a result, it is possible to prevent the joint 11, the electrical wiring 13, and the like from being visually recognized from the visual side of the panel portion 50.

The above-mentioned related configuration A is a configuration that reduces deterioration of the organic light emitting element due to moisture, oxygen, or the like. Specifically, in the related configuration A, the entire element substrate on which the organic light emitting element is mounted is covered with a protective film, an adhesive layer, or the like. Therefore, there is a problem that the weight of the display device as a product in the related configuration A is heavy.

Therefore, the video display device 100 of the present embodiment has a configuration for achieving the above effects. Therefore, the image display device 100 of the present embodiment can solve the above problem.

<Modification example 1>
The configuration of this modification is applied to the first embodiment. FIG. 6 is a cross-sectional view of the panel portion 50 having the configuration of the modified example 1. FIG. 7 is an enlarged view of a part of the panel portion 50 having the configuration of the modified example 1.

In the configuration of the first embodiment, the holding housing 6 is made of a non-transparent material. Further, the color of the adhesive portion 12 is the same as the color of the main surface 10a of the substrate 10. The color of the main surface 10a of the substrate 10 and the color of the adhesive portion 12 are, for example, black.

On the other hand, in this modification, as shown in FIGS. 6 and 7, each of the substrate 10 and the holding housing 6 is transparent. Therefore, the main surface 10a of the substrate 10 is also transparent. Further, the holding housing 6 is made of a transparent material. The transparent material constituting the holding housing 6 is, for example, glass, resin, or the like.

Further, in this modification, the adhesive portion 12 is transparent. That is, the color of the adhesive portion 12 is the same as the color of the main surface 10a of each of the two adjacent substrates 10. The adhesive portion 12 is made of a transparent adhesive. That is, the image display device 100 of this modification has a configuration in which the image display device 100 can be seen through when each LED 8 is turned off. In this modification, the refractive index of the convex portion 9 is equal to or less than the refractive index of the substrate 10.

Further, at least one place of the substrate 10 as each video display substrate 5 is provided with electrical wiring 13 as in the first embodiment. FIG. 8 is an enlarged view of a region of the substrate 10 having the configuration of the first modification in which the electrical wiring 13 is provided. With reference to FIG. 8, the electrical wiring 13 of this modification is not transparent. Therefore, if a non-transparent adhesive is used to fix the electrical wiring 13 to the substrate 10, the adhesive is more easily visible than the electrical wiring 13.

Therefore, the adhesive portion 12 is provided at the joint portion between the electric wiring 13 and the substrate 10 so that the transparent adhesive portion 12 covers one end side of the electric wiring 13. As a result, the electrical wiring 13 is fixed to the substrate 10.

Next, how the light emitted from the LED 8 travels will be described. In the following, the light emitted from the LED 8 toward the substrate 10 is also referred to as “light L2”. FIG. 9 is a diagram for explaining how the light L2 emitted from the LED 8 travels in the first modification. The light L1 emitted from the LED 8 toward the protective panel 7 is the same as in FIG. Therefore, in FIG. 9, only the light L2 emitted from the LED 8 toward the substrate 10 is shown.

Light L2 propagates along the yz plane as an example. According to Fresnel's equation, light has the above-mentioned properties a, b, c, d.

In the following, a configuration in which the convex portion 9 does not exist on the lateral side of the LED 8 is also referred to as a “comparative configuration Nam”. The comparative configuration Nam has a configuration different from that of the present modification. FIG. 9A is a diagram for explaining how light travels in the comparative configuration Nam.

In the comparative configuration Nam, the light L2 first reaches the substrate 10. The refractive index of the substrate 10 is larger than the refractive index of air. Therefore, most of the light L2 propagates inside the substrate 10, and another part of the light L2 is reflected by the substrate 10.

In the following, the angle formed by the direction in which the light L2 propagates and the z-axis direction is also referred to as the “light L2 angle”. According to Snell's law, in the region of the substrate 10 where the light L2 is irradiated, the larger the light L2 angle, the more the light component reflected by the substrate 10.

In the following, the configuration of the modified example 1 is also referred to as “configuration Am”. In the configuration Am, the convex portion 9 exists on the lateral side of the LED 8. Further, in the configuration Am, the refractive index of the convex portion 9 is equal to or lower than the refractive index of the substrate 10.

FIG. 9B is a diagram for explaining how light travels in the configuration of the first modification. In the configuration Am of the first modification, the light L2 first reaches the convex portion 9. In this case, most of the light L2 propagates inside the convex portion 9, and another part of the light L2 is reflected by the convex portion 9. Another portion of the light L2 reflected by the protrusion 9 is directed towards the LED 8 or the substrate 10.

In the following, in the configuration Am, most of the light L2 propagating inside the convex portion 9 is also referred to as “convex portion propagating light”. The convex propagating light reaches the substrate 10. The refractive index of the convex portion 9 is equal to or lower than the refractive index of the substrate 10. Therefore, most of the convex propagating light propagates inside the substrate 10. Another part of the convex propagating light is reflected by the substrate 10.

Another part of the convex portion propagating light reflected by the substrate 10 reaches the side surface of the convex portion 9. Another part of the light propagating to the convex portion 9 that has reached the side surface of the convex portion 9 is divided into light that passes through the side surface of the convex portion 9 and light that is reflected by the side surface of the convex portion 9. Therefore, a very small amount of light goes to the protective panel 7.

In the following, a configuration in which the convex portion 9 exists on the lateral side of the LED 8 and the refractive index of the convex portion 9 is larger than the refractive index of the substrate 10 is also referred to as “comparative configuration Nbm”. The comparative configuration Nbm has a configuration different from that of the present modification. FIG. 9C is a diagram for explaining how light travels in the comparative configuration Nbm.

In the comparative configuration Nbm, the light L2 first reaches the convex portion 9. In this case, as in FIG. 9B, most of the light L2 propagates inside the convex portion 9, and another part of the light L2 is reflected by the convex portion 9.

In the following, in the comparative configuration Nbm, most of the light L2 propagating inside the convex portion 9 is also referred to as “convex portion propagating light”. The convex propagating light reaches the substrate 10. The refractive index of the convex portion 9 is larger than the refractive index of the substrate 10. Therefore, most of the convex propagating light is reflected by the substrate 10. Another part of the convex propagating light propagates inside the substrate 10.

In the following, most of the convex-propagated light reflected by the substrate 10 is also referred to as "reflected convex-propagated light". The reflected convex portion propagating light reaches the side surface of the convex portion 9. In this case, most of the reflected light propagating from the convex portion passes through the side surface of the convex portion 9 and heads toward the protective panel 7. Further, another part of the reflected convex portion propagating light is reflected by the side surface of the convex portion 9. At this time, the light transmitted through the side surface of the convex portion 9 is transmitted through the region of the protective panel 7 slightly distant from the convex portion 9.

Therefore, in the comparative configuration Nbm shown in FIG. 9C, in addition to the light that directly reaches the protective panel 7 and is transmitted through the protective panel 7, among the light L2, a large amount of light reflected by the substrate 10 is generated. The area of the protective panel 7 that is distant from the LED 8 is transmitted. Therefore, in the situation where the panel unit 50 having the comparative configuration Nbm displays the image, the image is not clear and is a blurry image. Therefore, the refractive index of the convex portion 9 needs to be equal to or lower than the refractive index of the substrate 10.

As described above, according to this modification, the same effect as that of the first embodiment is obtained. Further, according to this modification, the refractive index of the convex portion 9 is equal to or less than the refractive index of the substrate 10 in the configuration using the transparent substrate 10 and the transparent holding housing 6. As a result, the quality of the image displayed by the panel unit 50 can be improved.

Further, according to this modification, the adhesive portion 12 is transparent in the configuration using the transparent substrate 10 and the transparent holding housing 6. As a result, it is possible to prevent the joint 11 from being visually recognized from the visual side of the panel portion 50.

(Other variants)
In the present invention, the embodiments and modifications can be freely combined, and the embodiments and modifications can be appropriately modified or omitted within the scope of the invention.

For example, the number of substrates 10 as the video display substrate 5 is not limited to a plurality, and may be 1.

Further, the number of the convex portions 9 provided on the main surface 10a of the substrate 10 is not limited to a plurality, and may be 1.

Although the present invention has been described in detail, the above description is exemplary in all embodiments and the invention is not limited thereto. It is understood that innumerable variations not illustrated can be assumed without departing from the scope of the present invention.

5 video display board, 6 holding housing, 7 protective panel, 8 LED, 9 convex part, 10 board, 12 adhesive part, 50 panel part, 100 video display device.

Claims

A video display device that displays video
A substrate having a main surface, which is a surface on the viewing side,
A holding housing for holding the substrate is provided.
A plurality of LEDs (Light Emitting Diodes) for expressing the image and a convex portion are provided on the main surface of the substrate.
The video display device further
The plurality of LEDs and a protective panel covering the convex portion are provided.
The convex portion extends from the main surface toward the protective panel.
The convex portion is configured so that the protective panel does not come into contact with the plurality of LEDs.
Video display device.
Each said LED is a micro LED or a mini-LED for representing a pixel in the image.
The video display device according to claim 1.
The height of the convex portion is higher than the height of each of the LEDs.
The video display device according to claim 1 or 2.
The convex portion is not in contact with the protective panel,
The video display device according to any one of claims 1 to 3.
A plurality of convex portions including the convex portion are provided on the main surface of the substrate.
The video display device according to any one of claims 1 to 4.
The holding housing holds a plurality of substrates including the substrate, and holds the substrate.
The plurality of substrates are arranged along a specific direction, and the plurality of substrates are arranged.
An adhesive portion is provided on the main surface of each of the two adjacent substrates included in the plurality of substrates.
The adhesive portion is provided so that the adhesive portion covers the joint which is the boundary between the two substrates.
The video display device according to any one of claims 1 to 5.
The color of the bonded portion is the same as the color of the main surface of each of the two substrates.
The video display device according to claim 6.
The adhesive portion is transparent,
The video display device according to claim 6 or 7.
Each of the substrate and the holding housing is transparent and
The refractive index of the convex portion is equal to or lower than the refractive index of the substrate.
The video display device according to any one of claims 1 to 8.