Image display device

Abstract

To provide a picture display unit whose border (joint) between display panels is hardly recognized.SOLUTION: A picture display unit (100) includes: a panel array (1) with a plurality of display panels (11, 12, 13) arranged in line on a single plane; a front transparent plate (5) arranged on a visible side surface of the panel array; and an adhesive sheet (2) arranged between the panel array and the front transparent plate. The adhesive sheet includes a light transmission area and light-shielding areas (56, 57) with a relatively smaller visible light transmission ratio. On a border between display panels neighboring the panel array, the light-shielding areas of the adhesive sheet are arranged.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an image display device in which a plurality of display panels are arranged side by side. Place Regarding. [Background technology]

[0002] Micro LED displays are attracting attention as the next generation of displays. Micro LED displays can achieve high definition and a wide viewing angle by densely packing LED elements. In addition, LED displays do not require color filters, so they can consume less power and have higher brightness.

[0003] As a technique for enlarging a display device such as an LED display, a tiling technique is known in which multiple display panels are arranged on the same surface to form a single image. In a tiling display device in which multiple display panels are arranged, it is expected that the seams (boundaries) between adjacent display panels will be recognized by the viewer. In Patent Document 1, the positional accuracy of the tiling is improved by providing an alignment member on the side of the display panel. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-45718 A Summary of the Invention [Problem to be solved by the invention]

[0005] In a tiling display device, even when display panels are arranged with no gaps between them, the boundaries between adjacent display panels may be visible due to diffuse reflection of external light or light from the display panels. In view of this problem, an object of the present invention is to provide an image display device in which the boundaries (seams) between display panels are difficult to see. [Means for solving the problem]

[0006] The image display device of the present invention includes a panel array in which a plurality of display panels are arranged side by side on the same plane, and a front transparent plate arranged on the viewing side surface of the panel array, and the display panels constituting the panel array and the front transparent plate are bonded together via a double-sided adhesive sheet. The display panel may be an LED panel.

[0007] The adhesive sheet has a light-transmitting region and a light-shielding region. The light-shielding region has a smaller visible light transmittance than the light-transmitting region, and the visible light transmittance of the light-shielding region is preferably 50% or less. The light-shielding region of the adhesive sheet is disposed on the boundary between adjacent display panels of the panel array. For example, when a plurality of display panels are disposed in a tiled pattern in the panel array, the boundary region has a lattice pattern so as to cover the boundary line between the display panels.

[0008] The pressure-sensitive adhesive sheet may have a patterned colored layer on a transparent pressure-sensitive adhesive layer. The colored layer is preferably provided on the main surface of the pressure-sensitive adhesive layer facing the display panel. The pressure-sensitive adhesive sheet may have a transparent pressure-sensitive adhesive layer laminated on both sides of a transparent substrate film, and a colored layer may be provided on one or both main surfaces of the transparent substrate film. The colored layer is preferably provided on the main surface of the transparent substrate film facing the display panel. In these pressure-sensitive adhesive sheets, the colored layer is provided in the light-shielding region. Effect of the Invention

[0009] By arranging a light-shielding area of ​​the adhesive sheet on the boundary between adjacent display panels of the panel array, the boundary between the display panels is difficult to see from the outside, and a seamless display can be achieved. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is an exploded perspective view of the image display device. [Diagram 2] FIG. 1 is a cross-sectional view of an image display device. [Diagram 3] FIG. 1 is a cross-sectional view of an LED panel array. [Figure 4] FIG. 2 is a cross-sectional view of the adhesive sheet. [Diagram 5] FIG. 1 is a cross-sectional view of an image display device. [Figure 6] FIG. 2 is a cross-sectional view of the adhesive sheet. [Figure 7] FIG. 1 is a cross-sectional view of an image display device. [Figure 8] FIG. 2 is a cross-sectional view of the adhesive sheet. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] 1 is an exploded perspective view of an image display device according to an embodiment. The image display device 100 includes a panel array 1 in which a plurality of display panels 11-19 are arranged in a tiled pattern on the same surface, and a front transparent plate 5 is arranged on the viewing side (light exit side) of the panel array 1. The display panels 11-19 constituting the panel array 1 and the front transparent plate 5 are bonded together with an adhesive sheet 2 arranged therebetween.

[0012] The adhesive sheet 2 has light-transmitting regions 31-39 and light-shielding regions in a grid pattern consisting of strip-shaped regions 51, 53 extending in the x direction and strip-shaped regions 56, 58 extending in the y direction. The visible light transmittance of the light-shielding regions is smaller than that of the light-transmitting regions. The light-transmitting regions 31-39 correspond to the positions of the display panels 11-19 constituting the panel array 1. The light-shielding regions 51, 53, 56, 58 of the adhesive sheet 2 are arranged on the boundary lines between adjacent display panels.

[0013] The adhesive sheet 2 is a double-sided adhesive sheet, and the first main surface on the viewing side is bonded to the front transparent plate 5, and the second main surface is bonded to the display panel. In the following, the main surface on the viewing side of each member may be referred to as the "first main surface" and the main surface on the opposite side (panel array side) as the "second main surface". The adhesive sheet may be a substrate-less adhesive sheet, or may be one in which adhesive layers are laminated on both sides of a transparent substrate film, as shown in Figs. 6 and 8. The light-shielding region of the adhesive sheet 2 may not have adhesive properties.

[0014] A front transparent plate 5 is disposed on the viewing side surface of the panel array 1, and each of the display panels 11 to 19 constituting the panel array 1 is bonded to the front transparent plate 5 via an adhesive sheet 2. The front transparent plate 5 is a transparent plate made of glass or resin having appropriate mechanical strength and thickness, and the provision of the front transparent plate makes it possible to prevent the image display panel from being damaged or scratched due to impact from the outer surface. A position sensor such as a touch panel may be provided on the front transparent plate.

[0015] Fig. 2 is a cross-sectional view taken along line AA in Fig. 1. Display panels 11-13 include a display element 7 on a support substrate 8. Types of display panels include self-luminous display panels such as LED panels and organic electroluminescence (EL) panels; and non-luminous display panels such as liquid crystal panels and electronic paper. The support substrate 8 and display element 7 in the display panels are appropriately determined depending on the type of display panel.

[0016] In the following, a case where the display panel is an LED panel will be described as an example. Fig. 3 is a cross-sectional view of a panel array 1 in which LED panels 11, 12, and 13, each having an LED array, are arranged in a tiled pattern on a support substrate 8.

[0017] The support substrate 8 is a member that supports the LED elements that constitute the display element 7, and is made of glass or various resin materials. The support substrate may be transparent or opaque. The thickness of the support substrate is not particularly limited as long as it can support the display element 7, and is, for example, about 10 μm to 2 mm.

[0018] The display element 7 of the LED panel is an LED array including a plurality of LED elements, and typically, a pixel P is composed of three color LED elements, a red LED element 6R, a green LED element 6G, and a blue LED element 6B, and a plurality of pixels are arranged in a tile pattern. LED elements can be miniaturized, making them suitable for achieving high definition. In a micro LED, the size (length of one side) of one LED element is, for example, about 5 μm to 200 μm, and the pixel pitch is about 20 μm to 1 mm. A transparent resin layer (not shown) may be provided on the surface of the LED element so as to cover the LED element.

[0019] A gap 96 exists at the boundary between adjacent display panels 11, 12, and a gap 98 exists at the boundary between adjacent display panels 12, 13. Even if the gap between adjacent display panels is made as small as possible, a step may occur due to a slight difference in height of the upper surface (element formation surface) of the support substrate 8. When external light from the viewing side or light from the LED elements is irradiated onto the gap between the panels or the step at the boundary, the light is diffusely reflected. Therefore, the intensity and color of the reflected light at the boundary differs from other areas of the display array, causing the boundary to be visually recognized.

[0020] As shown in FIG. 2, if the light-shielding areas 56, 58 of the adhesive sheet 2 are disposed on the boundary between adjacent display panels, the incidence of external light into the boundary area between the display panels can be reduced. In addition, even if light from the display element 7 is irradiated onto the boundary area, the light-shielding areas 56, 58 block the reflected light, so that the emission of the reflected light from the boundary area to the visible side can be reduced. Therefore, the boundary (seam) between the display panels is difficult to see (recognize) from the outside, and a seamless display can be realized. In addition, since the light-shielding areas are provided on the adhesive sheet 2 used for bonding the display panels 11, 12, 13 and the front transparent plate 5, the distance from the image display panel to the light-shielding areas is small, and light diffusely reflected at the boundary between the adjacent display panels can be efficiently blocked.

[0021] The width of the light-shielding region of the adhesive sheet 2 may be appropriately set depending on the gap between the display panels and the interval between adjacent pixels, for example, about 5 μm to 200 μm. When a gap exists between adjacent display panels, the width of the light-shielding region is preferably larger than the width of the gap between the panels. In addition, the width of the light-shielding region is preferably smaller than the distance L between the display elements of the adjacent display panels.

[0022] The visible light transmittance in the light-shielding region of the pressure-sensitive adhesive sheet 2 is preferably 50% or less, more preferably 30% or less, and even more preferably 10% or less. The visible light transmittance in the light-shielding region may be 5% or less, 3% or less, or 1% or less. From the viewpoint of efficiently emitting light from the display panel to the viewing side, the visible light transmittance in the light-transmitting region is preferably 75% or more, more preferably 80% or more, and even more preferably 85% or less.

[0023] The adhesive sheet 2 is a layer of adhesive. The adhesive may be selected from a variety of adhesives, including acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyvinyl ethers, vinyl acetate / vinyl chloride copolymers, modified polyolefins, epoxy-based, fluorine-based, and rubber-based polymers such as natural rubber and synthetic rubber. In particular, acrylic adhesives or rubber-based adhesives are preferred, as they have excellent optical transparency and adhesive properties such as appropriate wettability, cohesiveness, and adhesiveness.

[0024] A photocurable adhesive may be used as the adhesive constituting the adhesive sheet 2. The photocurable adhesive contains a base polymer and a photocuring agent, and further contains a photopolymerization initiator and / or a sensitizer. The photocurable adhesive is soft before photocuring, and has high conformability to unevenness and steps. Therefore, the adhesive can be easily filled without gaps even on the surface of an LED array having gaps between adjacent LED elements. The adhesive is photocured after the display panel and the front transparent plate are bonded together, thereby improving adhesion reliability.

[0025] In order to improve the filling ability of steps and unevenness, the light transmitting region of the adhesive sheet 2 has a shear storage modulus of 1×10 at a frequency of 1 Hz and 25° C. 6 Pa or less, and 5×10 5 It is more preferable that the shear storage modulus of the adhesive sheet at a frequency of 1 Hz and 25° C. is 1×10 Pa or less. Note that the light-shielding area of ​​the adhesive sheet 2 may have different characteristics from the light-transmitting area because it is not disposed on the display element of the display panel. From the viewpoint of preventing the adhesive from protruding from the edge and contamination due to the transfer of the adhesive, the shear storage modulus of the adhesive sheet at a frequency of 1 Hz and 25° C. is 1×10 4 Pa or more is preferable, 3×10 4 It is more preferable that the shear storage modulus is at least 1 Pa. When the pressure-sensitive adhesive sheet is photocurable, it is preferable that the shear storage modulus before photocuring is in the above range.

[0026] The thickness of the adhesive sheet 2 is not particularly limited, but may be, for example, about 10 to 500 μm, or about 20 to 300 μm. The light transmitting region of the adhesive sheet 2 preferably has an adhesive strength to a glass plate of 3 N / 20 mm or more. When the adhesive sheet is photocurable, the adhesive strength to glass after photocuring of the adhesive is preferably 3 N / 20 mm or more. The adhesive strength is the test strength when a 20 mm wide adhesive sheet is attached to a glass plate and a 180° peel test is performed at a peel speed of 300 mm / min.

[0027] The method of providing the patterned light-shielding region on the adhesive sheet 2 is not particularly limited. For example, the adhesive of the light-shielding region can be impregnated with a dye or pigment to color it, thereby imparting light-shielding properties. The light-shielding region of the adhesive sheet 2 does not need to have light-shielding properties over the entire thickness direction of the adhesive sheet. For example, the light-shielding region may be formed by impregnating the adhesive layer with a dye or pigment near the surface. The light-shielding region of the adhesive sheet does not need to be colored by the adhesive itself. For example, the light-shielding region may be formed by providing a colored layer on a transparent adhesive layer by printing or the like.

[0028] 4 is a cross-sectional view of an adhesive sheet 41 having colored layers 66, 68 provided on one main surface of a transparent adhesive layer 21. In this adhesive sheet 41, the areas where the colored layers 66, 68 are provided are light-shielding areas. As the transparent adhesive layer 21, an adhesive layer made of the same adhesive as described for the adhesive sheet above is suitably used.

[0029] 5 is a cross-sectional view of an image display device 101 in which the colored layer-forming surface of the adhesive sheet 41 is arranged to face the panel array. In this configuration, the colored layers 66, 68 are arranged in the gaps between the display elements 7 of adjacent display panels, making it difficult to visually recognize the boundaries between the display panels from the outside. In addition, the incidence of external light into the gaps between the panels is suppressed, and further, the light reflected at the boundary regions between the adjacent panels is blocked by the colored layers 66, 68, making it difficult to recognize the boundaries of the panel array.

[0030] The colored layers 66, 68 may be provided on either the first or second main surface of the transparent adhesive layer 21, or the colored layers may be provided on both surfaces. If the colored layer is provided on the second main surface (the surface facing the panel array), the colored layer is disposed directly above the image display panel or in the gap between adjacent image display panels, so that reflected light is less likely to be emitted to the outside, and the boundary region becomes less visible.

[0031] The method for providing a colored layer on the transparent adhesive layer is not particularly limited, and various printing methods such as inkjet printing, screen printing, etc. can be applied. Instead of forming a colored layer directly on the transparent adhesive layer, a colored pattern may be printed on another substrate, and the colored layer may be transferred onto the adhesive layer.

[0032] The thickness of the colored layer is not particularly limited and may be set according to the transmittance of the light-shielding region. In order to sufficiently reduce the light transmittance of the light-shielding region, the thickness of the colored layer is preferably 2 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. The thickness of the colored layer may be 50 μm or less, 40 μm or less, or 30 μm or less. The thickness of the colored layer is preferably 50% or less, more preferably 40% or less of the thickness of the adhesive layer.

[0033] 6 is a cross-sectional view of an adhesive sheet 43 according to another embodiment. The adhesive sheet 43 is a substrate-attached double-sided adhesive sheet in which adhesive layers are laminated on both sides of a transparent substrate film 81, with a first transparent adhesive layer 23 laminated on a first main surface of the transparent substrate film 81 and a second transparent adhesive layer 25 laminated on a second main surface of the transparent substrate film 81. Colored layers 76, 78 are provided on the second main surface of the transparent substrate film 81. In this adhesive sheet 44, the region in which the colored layers 76, 78 are provided on the transparent substrate film 81 is a light-shielding region.

[0034] Examples of plastic materials constituting the transparent substrate film 81 include polyester resins, polyolefin resins, cyclic polyolefin resins, polyamide resins, polyimide resins, polyether ether ketone, polyether sulfone, etc. The visible light transmittance of the transparent substrate film 81 is preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more. The thickness of the transparent substrate film is, for example, about 10 to 100 μm.

[0035] The method of providing a colored layer on a transparent substrate film is not particularly limited, and various printing methods such as inkjet printing and screen printing can be applied. When a colored layer is formed on a transparent substrate film, it has the advantage of being easier to print and having higher printing accuracy than when printing is performed on a pressure-sensitive adhesive layer. The thickness of the colored layer, the transmittance of the light-shielding region, etc. are as described above for the embodiment in FIG. 4.

[0036] The first transparent adhesive layer 23 and the second transparent adhesive layer 25 are preferably adhesive layers made of the same adhesive as that described for the adhesive sheet above. The first transparent adhesive layer 23 and the second transparent adhesive layer 25 may be the same or different in composition and thickness. Either or both of the first transparent adhesive layer 23 and the second transparent adhesive layer 25 may be a photocurable adhesive layer. Both the first transparent adhesive layer 23 and the second transparent adhesive layer 25 preferably have an adhesive strength to a glass plate of 3N / 20mm or more. At least the second transparent adhesive layer 25 to be attached to the display panel preferably has an adhesive strength to glass of 3N / 20mm or more.

[0037] 7 is a cross-sectional view of an image display device 103 in which the second transparent adhesive layer 25 of the adhesive sheet 43 is disposed so as to face the panel array. In this configuration, the colored layers 76, 78 provided on the second main surface of the transparent substrate film 81 have the effect of suppressing the incidence of external light into the gaps between the panels and blocking light reflected at the boundary regions between adjacent panels, making it difficult to recognize the boundaries of the panel array.

[0038] The colored layers 76, 78 may be provided on either the first or second main surface of the transparent substrate film 81, or the colored layers may be provided on both surfaces. If the colored layer is provided on the second main surface (the surface facing the panel array), the distance between the image display panel and the colored layer is small, so that reflected light is less likely to be emitted to the outside, and the boundary region becomes less visible.

[0039] From the viewpoint of reducing the distance between the image display panel and the colored layer to suppress the boundary region from being visible, the thickness of the second transparent adhesive layer 25 may be made smaller than the thickness of the first transparent adhesive layer 23. From the viewpoint of filling the unevenness of the image display panel surface (for example, gaps between adjacent LED elements) with the adhesive without any gaps and enhancing adhesion reliability, a photocurable adhesive may be used as the second transparent adhesive layer 25.

[0040] In the embodiment shown in FIG. 6, an example in which a colored layer is provided on the surface of the transparent substrate film 81 is shown, but as in the adhesive sheet 44 shown in FIG. 8, the resin constituting the transparent substrate film 82 may be colored in regions 86 and 88 to form light-shielding regions. The method of coloring the resin constituting the substrate film is not particularly limited. For example, a colored resin material may be used to form the light-shielding regions and a transparent resin material may be used to form the light-transmitting regions by using 3D printing technology or the like. In addition, the resin constituting the substrate film may be colored by impregnating the transparent resin film with a dye or pigment.

[0041] The above explanation has focused on the case where the display panel is an LED panel (LED array), but the technology of making the gaps between panels less visible by using an adhesive sheet with a light-shielding area can also be applied to display panels other than LED panels. In addition, the arrangement of multiple display panels does not need to be in a tiled (grid) pattern, and can be changed as appropriate depending on the shape of the display panel, the shape of the array, etc. The pattern shape of the light-shielding area of ​​the adhesive sheet can be designed to cover the boundary line between the display panels. [Explanation of symbols]

[0042] 1 Panel Array 11~19 Display Panel 7 Display element 8 Supporting substrate 2,41,43,44 Adhesive sheet 21, 23, 25 Adhesive layer 31~39 Light transmission area 51,53,56,58 Shade area 5 Front transparent plate 81 Transparent substrate film 66,68,76,78 Colored layer (shading area) 100,101,103 Image display increase value

Claims

1. A panel array in which multiple display panels are arranged side by side on the same surface; a front transparent plate disposed on the viewing surface of the panel array; and an adhesive sheet provided between the panel array and the front transparent plate; a first main surface of the adhesive sheet is bonded to the transparent plate, and a second main surface of the adhesive sheet is bonded to the display panel; the pressure-sensitive adhesive sheet has a light-transmitting region and a light-shielding region having a visible light transmittance lower than that of the light-transmitting region, the light-transmitting region of the pressure-sensitive adhesive sheet having a shear storage modulus of 1×10 6 Pa or less at a frequency of 1 Hz and 25° C.; An image display device, wherein a light-shielding area of ​​the adhesive sheet is disposed on a boundary between adjacent display panels of the panel array.

2. The image display device described in Claim 1, wherein the adhesive sheet comprises a transparent adhesive layer and a patterned colored layer provided on a light-shielding area of ​​at least one main surface of the transparent adhesive layer.

3. An image display device as described in claim 1, wherein the multiple display panels are arranged in a tiled pattern in the panel array.

4. An image display device described in any one of claims 1 to 3, wherein the display panel is an LED panel.

5. An image display device described in any one of claims 1 to 3, wherein the adhesive sheet is a substrateless adhesive sheet that does not include a substrate film.

6. An image display device described in any one of claims 1 to 3, wherein the second main surface of the adhesive sheet has an adhesive strength to glass of 3 N / 20 mm or more.

Images