Indication device

Abstract

To maintain the adhered position of a color separation element board and a liquid crystal panel at the initial position, even after reliability test under a high temperature environment is carried out.SOLUTION: A display device according to an embodiment comprises: a liquid crystal panel that injects backlight coming from a light source and absorbs a designated color component by a color filter in accordance with a display video; and a color separation element board which is disposed between the liquid crystal panel and the light source, and in which a color separation element is formed on one plane of a transparent material board. A junction area of a given width is provided at a circumferential edge of a plane of the color separation element board that faces the liquid crystal panel, and a color separation groove, which serves as a color separation element, is formed in an effective display area in the inside of the junction area. A junction area of a given width is provided at a circumferential edge of the transparent material board on the backlight incident surface side of the liquid crystal panel, and a polarizing plate is disposed in the inside of the junction area. The junction area of the color separation element board and the junction area of the liquid crystal panel are joined together via a sealant layer to which a coating of sealant is applied and then cured.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION Embodiments of the present invention relate to display devices that use color separation element technology. [Background technology]

[0002] Color filter (CF) type display devices used in liquid crystal display modules have liquid crystal panels (panels consisting of a TFT (thin-film-transistor) substrate laminated with a CF substrate) that have RGB CF formed on a pixel-by-pixel basis. By illuminating white backlight from a light source through the filters of each RGB pixel in accordance with the displayed image, light with wavelengths of the CF color is transmitted and light with wavelengths other than CF is absorbed. This results in low light utilization efficiency. Therefore, light separation element technology has been proposed to improve light utilization efficiency.

[0003] Color separation element technology uses a color separation element, which has color separation grooves formed on the surface of a glass substrate with a predetermined pattern of unevenness, to diffract and separate white backlight into specific directions for each RGB wavelength component. In a CF-type display device, this technology places a glass substrate with the color separation element (hereinafter referred to as the color separation element substrate) between the backlight light source and the TFT substrate, facing each other. The color separation element separates the backlight into wavelengths corresponding to the RGB CFs, diffracts them in specific directions, and allows only the light with wavelengths corresponding to the CFs to enter the filters of each RGB pixel via the TFT substrate. This reduces absorption of light other than those corresponding to the CFs, improving light (brightness) utilization efficiency.

[0004] However, an air gap (air gap) is required between the color separation element substrate and the TFT substrate to spatially separate the diffracted light for each color. Therefore, a method is being considered in which the edge of the TFT substrate and the periphery of the color separation element substrate are attached with double-sided tape shaped roughly like a square, and the thickness of the double-sided tape is used to form the gap.

[0005] However, when using double-sided tape for adhesion, warping can occur in the TFT substrate during reliability tests simulating high-temperature environments, causing the adhesion position to shift from its initial position. This occurs because the polarizing plate attached to the TFT substrate shrinks during testing, causing the TFT substrate to bend, which in turn deforms the double-sided tape and causes misalignment. This can hinder reliability tests under high-temperature environments and make it difficult to accommodate narrower frame sizes for display devices. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2018-146750 A [Patent Document 2] Japanese Patent Publication No. 2020-158358 Summary of the Invention [Problem to be solved by the invention]

[0007] As described above, in conventional CF-type display devices, when adopting light separation element technology, a method of bonding the color separation element substrate and liquid crystal panel with double-sided tape has been considered. However, when bonding with double-sided tape, a problem occurs in which the bonding position shifts from its initial position due to warping of the liquid crystal panel when reliability tests are conducted in a high-temperature environment.

[0008] Therefore, the present embodiment aims to provide a display device that can maintain the adhesive position between the color separation element substrate and the liquid crystal panel in the initial position even after conducting a reliability test assuming a high-temperature environment. [Means for solving the problem]

[0009] The display device according to this embodiment is With color filters An LCD panel, a light source that irradiates white light toward the liquid crystal panel;The color separation element substrate is disposed between the liquid crystal panel and the light source, and has a transparent material substrate on one side of which a color separation element is formed. The color separation element substrate has a bonding area of ​​a certain width on the periphery of the surface facing the liquid crystal panel, and a color separation groove that becomes the color separation element is formed in the effective display area inside the bonding area. The liquid crystal panel has light A bonding region of a certain width is provided on the periphery of the transparent material substrate on the incident surface side of the polarizer, and a polarizer is disposed inside the bonding region. A first groove having a width of 1 μm to 3 μm and a depth of 3 μm to 4 μm is provided in the bonding region of the color separation element substrate, and the sealing material layer is disposed in the first groove. . [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is an exploded perspective view showing the basic configuration of a display device according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing a layered structure of the display device according to the embodiment. [Figure 3] FIG. 3 is a front view showing the structure of a color separation element substrate of the display device according to the embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing a warpage state when a reliability test is performed in a high-temperature environment on the display device according to the embodiment. [Figure 5] FIG. 5 is a front view showing another structure of the color separation element substrate of the display device according to the embodiment. [Figure 6] FIG. 6 is a cross-sectional view showing a specific structure of the color separation element applied to this embodiment. [Figure 7] FIG. 7 is a cross-sectional view showing a specific example of processing of the color separation element shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, with reference to the drawings, a detailed description will be given of the best mode for carrying out the present invention (hereinafter simply referred to as an embodiment). It should be noted that the disclosure is merely an example, and appropriate modifications that a person skilled in the art can easily conceive while maintaining the gist of the invention are naturally included within the scope of the present invention. Furthermore, in order to clarify the explanation, the drawings may show the width, thickness, shape, etc. of each part schematically compared to the actual embodiment, but these are merely examples and are not intended to limit the interpretation of the present invention. Furthermore, in this specification and each drawing, components that perform the same or similar functions as those described above with reference to the previous drawings are designated by the same reference numerals, and redundant detailed descriptions may be omitted as appropriate.

[0012] First, the color separation element applied to this embodiment will be described with reference to FIGS.

[0013] FIG. 6 is a cross-sectional view showing a specific structure of a color separation element, and FIG. 7 is a cross-sectional view showing an example of color separation of backlight by the color separation element shown in FIG.

[0014] That is, the color separation element is formed by forming grooves with a minimum structural width of 1 μm to 3 μm and a maximum depth of 3 μm to 4 μm in a predetermined pattern corresponding to RGB on a glass substrate, as shown in Fig. 6. Hereinafter, these grooves will be referred to as color separation grooves 111. Furthermore, the glass substrate on which the color separation grooves 111 are formed will be referred to as color separation element substrate 11.

[0015] When backlight (white light) emitted from a light source is incident directly on the color filters, the R, G, and B filters absorb all light except for R, G, and B, as shown in Figure 7(a). In contrast, when backlight (white light) is incident on the color filters via the color separation element substrate 11, the R, G, and B light is diffracted in different directions and focused on the filters of each color, as shown in Figure 7(b). This reduces light absorption in the color filters, thereby improving the efficiency of light (brightness).

[0016] Hereinafter, an embodiment of a display device using the above-described color separation element substrate 11 will be described.

[0017] (First embodiment) Fig. 1 is an exploded perspective view showing the basic configuration of a display device according to a first embodiment, Fig. 2 is a cross-sectional view showing the layered configuration of the display device according to the embodiment, and Fig. 3 is a front view showing the structure of a color separation element substrate of the display device according to the embodiment. The display device shown in Figs. 1 and 2 has a layered structure in which a color separation element substrate 11 and a liquid crystal panel 21 are bonded together via a sealant layer 31.

[0018] First, a bonding region of a certain width is secured on the periphery of the color separation element substrate 11, and a color separation groove 111 is formed in the effective display area on the inner upper surface of the bonding region. In addition, a color separation groove 112 having a smaller width than the bonding region is formed separately in the center of the bonding region, perpendicular to the longitudinal direction, as shown in Fig. 3.

[0019] On the other hand, the liquid crystal panel 21 has a structure in which, from the incident side of the backlight emitted from the light source 41, a lower polarizer 211, a TFT substrate 212, a liquid crystal layer 213, a CF layer 214, a CF glass substrate 215, and an upper polarizer 216 are laminated. A bonding region of a certain width from the periphery is secured on the backlight incident side of the TFT substrate 212. The lower polarizer 211 is attached to the effective display area inside the bonding region.

[0020] Although not described in detail, pixel TFTs are formed on the glass substrate of the TFT substrate 212, each of which is provided for each of a plurality of pixels. A CF glass substrate 215 including a CF layer 214 is referred to as a CF substrate. The TFT substrate 212 and the CF substrate are bonded together by a sealant layer, and the liquid crystal layer 213 is sealed between the TFT substrate 212 and the CF substrate by the sealant layer.

[0021] To assemble a display device with the above configuration, a liquid sealant 31 containing filler is applied to the adhesive surface of the color separation element substrate 11 in the bonding area around the periphery of the substrate 11. The sealant 31 is applied, for example, by drawing a frame shape using a dispenser. After the sealant 31 is applied, it is bonded to the bonding area around the periphery of the TFT substrate 212 and fixed by thermal curing or ultraviolet curing. Here, since the color separation grooves 112 are formed in the bonding area of ​​the color separation element substrate 11, the liquid sealant 31 penetrates into the grooves when applied, thereby improving adhesive strength. Here, the sealant 31 is in a state before thermal curing or ultraviolet curing, and the sealant 31 after thermal curing or ultraviolet curing is referred to as the sealant layer 31.

[0022] In addition, a cutout portion that serves as an air hole 32 is formed in a part of the sealing material layer 31. The air hole 32 functions as a dew condensation prevention measure for the internal space, preventing the inside from fogging up (condensation) due to a temperature difference occurring between the outside of the display device and the area between the color separation element substrate 11 and the lower polarizing plate 211.

[0023] The effects of the display device having the above configuration will be described below in comparison with the conventional display device.

[0024] In the conventional double-sided tape adhesion structure, the color separation element substrate 11 and the TFT substrate 212 are adhered with double-sided tape, so after a reliability test (high-temperature environment) is conducted, misalignment occurs between the color separation element substrate 11 and the TFT substrate 212, resulting in an RGB display area that differs from the initial state. This is because the polarizing plate shrinks during the reliability test in a high-temperature environment, causing the liquid crystal panel to bend, which in turn deforms the double-sided tape and causes misalignment.

[0025] In contrast, when a sealant 31 is used as the bonding material and is formed by thermal or ultraviolet curing, it is less likely to deform than tape. Therefore, in this embodiment, a sealant adhesive structure is adopted to increase the rigidity of the adhesive and prevent deformation, taking into account the fact that the deformation of the adhesive due to the bending of the LCD panel caused by the contraction of the polarizing plate can cause misalignment. As a result of this structure, no misalignment was observed even after reliability testing in a high-temperature environment. Furthermore, it was confirmed that when the sealant comes into contact with the color separation grooves formed in the bonding area, it spreads due to capillary action. This increases the bonding area, strengthening the bond and making it less likely to cause misalignment.

[0026] FIG. 5 is a front view showing another structure of the color separation element substrate of the display device according to the embodiment. In the above embodiment, the color separation groove 112 is formed in the bonding region of the color separation element substrate 11. However, as shown in FIG. 5, it is also preferable to form inner grooves 113 and 114 and outer grooves 115 and 116, respectively, on the inside and outside of the color separation groove 112 along the long side of the substrate 11. That is, the color separation element substrate 11 has the color separation grooves 111 and 112 formed in a direction perpendicular to the longitudinal direction, but two horizontal grooves are added to each of the upper and lower longitudinal sides of the color separation groove 112 formed on the periphery. These grooves 113 to 116 are wider and deeper than the color separation groove 112. This can prevent the sealant from spilling out when applied. In particular, this can prevent spilling into the effective display area and prevent degradation of color separation performance.

[0027] 5, it is preferable to provide a square-shaped groove 117 that is wider and deeper than the color separation groove 112 around the entire periphery of the effective display area between the grooves 113 to 116 and the color separation groove 112. This can reliably prevent the sealant from entering the effective display area.

[0028] In addition, in FIG. 5, the inner grooves 113 and 114 and the outer grooves 115 and 116 are formed, but only the inner grooves 113 and 114 may be formed.

[0029] As described above, according to this embodiment, the color separation element substrate 11 and the liquid crystal panel 21 can be firmly integrated with a uniform gap and without misalignment. In this embodiment, the number of joining steps increases because separate members are used for joining, but the use of a sealant sufficiently reduces the risk of misalignment compared to when double-sided tape is used.

[0030] In the above embodiment, the color separation element substrate and the TFT substrate are both processed glass materials, but they may be made of a transparent material such as resin.

[0031] Furthermore, the present invention is not limited to the above-described embodiments, and in the implementation stage, the components can be modified and embodied without departing from the spirit of the invention. Furthermore, various inventions can be formed by appropriately combining multiple components disclosed in the above-described embodiments. For example, some components may be omitted from all the components shown in the embodiments. Furthermore, components from different embodiments may be appropriately combined. [Explanation of symbols]

[0032] 11...color separation element substrate, 111, 112...color separation groove, 113, 114...inner groove, 115, 116...outer groove, 117...R-shaped groove, 21...liquid crystal panel, 211...lower polarizing plate, 212...TFT substrate, 213...liquid crystal layer, 214...CF layer, 215...CF glass substrate, 216...upper polarizing plate, 31...sealing material layer, 32...air hole, 41...light source.

Claims

1. A liquid crystal panel equipped with a color filter; a light source that irradiates white light toward the liquid crystal panel; a color separation element substrate disposed between the liquid crystal panel and the light source, the color separation element being formed on one surface of a transparent material substrate; Equipped with a bonding region of a certain width is provided on the peripheral edge of the surface of the color separation element substrate facing the liquid crystal panel, and a color separation groove serving as a color separation element is formed in an effective display area inside the bonding region; The liquid crystal panel has a bonding region of a certain width provided on the periphery of the transparent material substrate on the light incident surface side, and a polarizing plate disposed inside the bonding region, the bonding area of ​​the color separation element substrate and the bonding area of ​​the liquid crystal panel are bonded via a sealant layer formed by applying and curing a thermosetting or ultraviolet curing sealant; a first groove having a width of 1 μm to 3 μm and a depth of 3 μm to 4 μm is provided in the bonding region of the color separation element substrate; The display device has the sealing material layer disposed in the first groove.

2. 2. A display device according to claim 1, wherein a second groove for preventing the sealing material from overflowing is formed in a direction perpendicular to the formation direction of the first groove, at least on the effective display area side of the color separation groove formed in the center of the bonding area of ​​the color separation element substrate.

3. 2. A display device according to claim 1, wherein a third groove for preventing the sealing material from spilling out is formed around the periphery of the effective display area of ​​the color separation element substrate.

4. 2. The display device according to claim 1, wherein the sealing material layer has a cutout portion formed in a part thereof to serve as an air hole.

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