Liquid crystal display device

Abstract

To provide a liquid crystal display device in which a boundary between a display region and a light-shielding region is made seamless.SOLUTION: A liquid crystal display device 100 includes: a liquid crystal module 20; a cover glass 40 provided on the liquid crystal module 20; a black mask 42 as a light-shielding region formed on an outer periphery of a back surface side of the cover glass 40; and an antireflection layer 110 formed on a front surface side of the cover glass 40. The antireflection layer 110 includes a first antireflection layer 110A corresponding to a display region and a second antireflection layer 110B corresponding to the black mask 42. A reflectance generated at a front surface of the second antireflection layer 110B is greater than a reflectance generated at a front surface of the first antireflection layer 110A.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a liquid crystal display device, and more particularly to making the boundary between a display area for displaying an image and a light-shielding area seamless. [Background technology]

[0002] A liquid crystal display device includes a liquid crystal module housed in a housing, and the liquid crystal module is configured to include a liquid crystal panel and a protective cover attached to the surface of the liquid crystal panel. The liquid crystal display device has a display area (active area) for displaying an image and a light-shielding area surrounding the display area, and a so-called black mask that defines the light-shielding area is formed on the outer periphery of the protective cover. The black mask is, for example, an area printed in black on the protective cover. For example, the liquid crystal display device of Patent Document 1 provides an intermediate layer with a checkered pattern or the like in the black mask to prevent the black mask from being noticeable. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-15772 A Summary of the Invention [Problem to be solved by the invention]

[0004] A schematic cross section of a conventional liquid crystal display device is shown in Fig. 1. The liquid crystal display device 10 includes a liquid crystal module 20, a cover glass 40 provided on the liquid crystal module 20 via an optical clear film (OCR) or an optical clear adhesive (OCA) 30, and an anti-reflection layer (AR) or an anti-static film (ASF) 50 formed on the surface of the cover glass 40, all of which are housed within a housing.

[0005] The liquid crystal module 20 is configured by laminating, in order from the bottom, a polarizing plate 21, a glass substrate 22, an AR substrate with TFTs (TFT: Thin film transistor, AR: Array) 23 formed on the glass substrate 22, a liquid crystal panel 24 including RGB filters and liquid crystal molecules, a glass substrate 25, a shield electrode 26, and a polarizing plate 27. In addition, a backlight (not shown) is disposed below the liquid crystal module 20.

[0006] The liquid crystal panel 24 is, for example, an IPS type in which liquid crystal molecules rotate in a direction parallel to the panel when a voltage is applied via a TFT. Normally, in an IPS type, a shield electrode 26 for discharging the electric charge stored above the liquid crystal panel 24 to GND (reference potential) is disposed between the glass substrate 25 and the polarizing plate 27. The shield electrode 26 is made of, for example, a transparent metal material that transmits light, such as ITO.

[0007] A black mask 42 is formed on the outer periphery of the cover glass 40 so as to surround an active area that displays an image. The black mask 42 is formed, for example, by screen printing a black pigment on the bottom surface of the cover glass 40, and the black mask 42 defines a light-shielding region.

[0008] In such a liquid crystal display device 10, light from above (that is, when the liquid crystal display device is viewed from above) causes the following reflections depending on the reflectance of the surfaces and the reflectance of the interfaces of the layers. R1: reflection of the surface of the anti-reflection film / anti-static film 50, reflectance = about 0.3%, R2: Reflection at the interface of the black mask area 42, reflectance = approximately 0.2% R3: Reflection at the interface between the shield electrode 26 and the glass substrate 25, reflectance = approximately 0.7% R4: Reflection at the interface between the glass substrate 25 and the liquid crystal panel 24, reflectance = approximately 0.2% R5: Reflection at the interface between the liquid crystal panel 24 and the TFT 23, reflectance = approximately 0.2% In addition, since the refractive index of polarizing plates, OCA, and glass is approximately 1.5, there is almost no reflection at the interface due to the difference in refractive index.

[0009] Active area reflectance R A is R A = R1 + R3 + R4 + R5 ≒ 1.4%, and the reflectance of the black mask area R B is R B = R1 + R2 ≒ 0.5%, and the reflectance of the active area R A is the reflectance of the black mask area R B Conventionally, in order to make this boundary less visible, the reflectance R B or increase the reflectance of the active area R A Approaches have been taken to modify the reflectance, either by lowering the reflectance or by both.

[0010] However, in the conventional method, the reflectance R of the black mask area B In order to increase the reflectance, the pigment was adjusted, but due to reasons such as reliability and material restrictions due to color, there is a limit to how much the pigment can be adjusted, and it is not possible to increase the reflectance significantly. A In order to reduce this, it is possible to change the metal material (e.g., ITO) of the shield electrode 26 to an organic conductive material (e.g., conductive plastic, etc.); however, this increases the resistance value of the shield electrode 26, which may result in insufficient discharge of charges due to ESD (Electrical Static Discharge).

[0011] The present invention is intended to solve such problems in the prior art, and has an object to provide a liquid crystal display device that makes the boundary between the display area for displaying an image and the light-shielding area seamless. [Means for solving the problem]

[0012] The liquid crystal display device of the present invention comprises a liquid crystal module, a cover glass provided on the liquid crystal module, a light-shielding area formed on the outer periphery of the back surface side of the cover glass, and an anti-reflection layer formed on the front surface side of the cover glass, the anti-reflection layer including a first anti-reflection layer corresponding to a display area for displaying an image and a second anti-reflection layer corresponding to the light-shielding area, and the reflectance generated on the surface of the second anti-reflection layer is greater than the reflectance generated on the surface of the first anti-reflection layer.

[0013] In one embodiment, the reflectances of the first and second antireflection layers are determined so that the sum of the reflectance occurring at the interface of the light-shielding region and the reflectance occurring at the surface of the second antireflection layer is approximately equal to the sum of the reflectance occurring at the interface of each layer in the liquid crystal module in the display region and the reflectance occurring at the surface of the first antireflection layer. In one embodiment, the reflectance occurring at the interface of each layer in the liquid crystal module includes the reflectance occurring at the interface between the seal electrode and the glass substrate, the reflectance occurring at the interface between the glass substrate and the liquid crystal panel substrate, and the reflectance occurring at the interface between the liquid crystal panel and the TFT substrate.

[0014] Furthermore, the liquid crystal display device of the present invention comprises a liquid crystal module, a cover glass provided on the liquid crystal module, a light-shielding area formed on the outer periphery of the back side of the cover glass, an adhesive portion formed on the front side of the cover glass, and an anti-reflection layer formed on the adhesive portion, the adhesive portion including a first adhesive portion corresponding to a display area for displaying an image and a second adhesive portion corresponding to the light-shielding area, and the reflectance generated at the interface between the second adhesive portion and the anti-reflection layer is greater than the reflectance generated at the interface between the first adhesive portion and the anti-reflection layer.

[0015] In one embodiment, the reflectances of the first and second adhesive parts are determined so that the sum of the reflectance occurring at the interface of the light-shielding region, the reflectance occurring at the interface of the second adhesive part, and the reflectance occurring at the surface of the antireflection layer is approximately equal to the sum of the reflectance occurring at the interface of each layer in the liquid crystal module in the display region, the reflectance occurring at the interface of the first adhesive part, and the reflectance occurring at the surface of the antireflection layer. In one embodiment, the reflectance occurring at the interface of each layer in the liquid crystal module includes the reflectance occurring at the interface between the glass substrate and the liquid crystal panel substrate, and the reflectance occurring at the interface between the liquid crystal panel and the TFT substrate. In one embodiment, the shield electrode is made of an organic conductive film, and reflection occurring at the interface between the seal electrode and the glass substrate is suppressed. Effect of the Invention

[0016] According to the present invention, by making the reflectance occurring at the surface of the second antireflection layer corresponding to the light-shielding region larger than the reflectance occurring at the surface of the first antireflection layer corresponding to the display region, the reflectance difference between the light-shielding region and the display region is reduced, and the boundary between the light-shielding region and the display region can be made seamless so as not to be noticeable.Furthermore, according to the present invention, by making the reflectance occurring at the interface of the second adhesive portion corresponding to the light-shielding region larger than the reflectance occurring at the interface of the first adhesive portion corresponding to the display region, the reflectance difference between the light-shielding region and the display region is reduced, and the boundary between the light-shielding region and the display region can be made seamless so as not to be noticeable. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic configuration of a conventional liquid crystal display device. [Diagram 2] FIG. 2A is a schematic plan view of a liquid crystal display device according to a first embodiment of the present invention, and FIG. 2B is a schematic cross-sectional view taken along line AA of FIG. [Diagram 3] 3A to 3C are cross-sectional views illustrating an example of a manufacturing process for the antireflection layer in the first embodiment. [Figure 4] FIG. 4 is a schematic cross-sectional view of a liquid crystal display device according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The present invention is applicable to liquid crystal display devices equipped with a touch panel function as a user interface, and liquid crystal display devices equipped with a function for detecting the approach of a user's finger or the like by using infrared rays, in addition to liquid crystal display devices equipped with a normal image display function. EXAMPLES

[0019] Next, an embodiment of the present invention will be described with reference to the drawings. Note that the scale of the drawings is exaggerated in order to facilitate understanding of the invention, and does not necessarily represent the scale of an actual product.

[0020] FIG. 2(A) is a schematic plan view of a liquid crystal display device according to a first embodiment of the present invention, and FIG. 2(B) is a schematic cross-sectional view taken along line AA. As shown in FIG. 2(A), the liquid crystal display device 100 according to this embodiment is configured by accommodating a backlight and a liquid crystal module 200 in a roughly rectangular housing. When viewed from above, the liquid crystal display device 100 has a rectangular active area (display area) P that displays an image, and a light-shielding area Q that surrounds the periphery of the active area P. The light-shielding area Q is a non-display area in which no image is displayed. When the liquid crystal display device 100 is equipped with a touch panel, the active area P is also an area where a touch operation is possible. The dashed line B virtually indicates the boundary between the active area P and the light-shielding area Q, but in reality, such a boundary B is not visible, or even if it is visible, it is barely noticeable.

[0021] 2(B), the liquid crystal display device 100 includes a liquid crystal module 20, which is configured similarly to the liquid crystal module 20 shown in Fig. 1. That is, the liquid crystal module 20 is configured by laminating, from the bottom, a polarizing plate 21, a glass substrate 22, an AR substrate with TFT (TFT: Thin film transistor, AR: Array) 23 formed on the glass substrate 22, a liquid crystal panel 24 including RGB filters and liquid crystal molecules, a glass substrate 25, a shield electrode 26, and a polarizing plate 27. The liquid crystal panel 24 is, for example, an IPS type in which liquid crystal molecules rotate in a direction horizontal to the panel due to a voltage applied via the TFT.

[0022] A cover glass (protective glass) 40 is attached on the polarizing plate 27 of the liquid crystal panel 20 via an optically adhesive resin (OCR) or an optically adhesive cohesive (OCA) 30. A black mask 42 that defines a light-shielding region Q is formed on the back side of the cover glass 40 by screen printing or the like.

[0023] An anti-reflection layer 110 is formed on the front surface side of the cover glass 40. The anti-reflection layer 110 includes a first anti-reflection layer 110A having a shape corresponding to the active area P and a black mask 42. or a second antireflection layer 110B having a shape corresponding to the light-shielding region Q. The second antireflection layer 110B is configured to have a higher surface reflectance than the first antireflection layer 110A. More specifically, the reflectance R A (R A =R1+R3+R4+R5) and the reflectance of the black mask area R B (R B =R BM +R2) are roughly equal, or the difference in reflectance between the two is small (R A ≒R B ), the reflectance R1 of the first antireflection layer 110A and the reflectance R of the second antireflection layer 110B BM is adjusted.

[0024] The cover glass 40 normally has a reflectance of 3 to 4%, but the reflectance can be reduced by forming the antireflection layer 110. The first antireflection layer 110A is not particularly limited in terms of its material or thickness, but may be composed of a single layer or a multilayer. In the case of a multilayer, for example, a low refractive index material (e.g., MgF 2 , SiO 2 , Al 2 O 3 ) and high refractive index materials (e.g., ZrO 2 , CEO 2 A high reduction in reflectance can be achieved by alternately laminating a ZnS layer and a ZnS layer. The first antireflection layer 110A is formed, for example, by evaporating, sputtering, or applying a material onto the surface of the cover glass 40. For example, the reflectance of the surface of the first antireflection layer 110A is R1≈0.3%, similar to the antireflection layer of the liquid crystal display device 10 of FIG.

[0025] The second antireflection layer 110B is not particularly limited in terms of its material or thickness, but may be made of, for example, a resin or paint containing hollow nano-silica. For example, the reflectance R BM When the reflectance R1 of the first antireflection layer 110A is ≈0.3%, R BM ≒1.2%.

[0026] FIG. 3 shows an example of a method for manufacturing the first antireflection layer 110A and the second antireflection layer 110B. As shown in FIG. 3(A), a mask member 120 patterned to expose the active area P is formed on the cover glass 40, and then, as shown in FIG. 3(B), a material for forming the first antireflection layer 110A is evaporated in the area exposed by the mask member 120. Then, as shown in FIG. 3(C), the mask member 120 is removed, and then, as shown in FIG. 3(D), a material for forming the second antireflection layer 110B is applied to the area surrounding the first antireflection layer 110A. As a result, an antireflection layer 110 having two antireflection layers with different reflectances, the first antireflection layer 110A corresponding to the active area P and the second antireflection layer 110B corresponding to the light-shielding area Q, is formed on the cover glass 40.

[0027] In the liquid crystal display device 100 configured as above, the reflectance when viewed from above is determined by the reflectance of the surface and the reflectance of the interface. A is R A = R1 (0.3%) + R3 (0.7%) + R4 (0.2%) + R5 (0.2%) = 1.4%. On the other hand, the reflectance R B is R B =R BM (1.2%)1+R2(0.2%)=1.4%, and the reflectance of the active area R A and the reflectance of the black mask area R B In this way, by eliminating the difference in reflectance between the active area and the black mask area, the boundary B between the active area P and the light-shielding area Q can be made inconspicuous, and the boundary B can be made seamless.

[0028] Next, a second embodiment of the present invention will be described. In the first embodiment, the first anti-reflection layer 110A and the second anti-reflection layer 110B having different refractive indices are formed on the cover glass 40. In the second embodiment, however, an adhesive material having different refractive indices is formed on the cover glass 40, and an anti-reflection layer is formed on the adhesive material.

[0029] Fig. 4 is a cross-sectional view showing a schematic configuration of a liquid crystal display device of the second embodiment, and the same reference numerals are used for the same components as those shown in Fig. 2. As shown in Fig. 4(A), in a liquid crystal display device 100A of the second embodiment, a film-like anti-reflection film 200 is attached to the surface of a cover glass 40 via an adhesive material 210.

[0030] The adhesive material 210 has a first adhesive portion 210A having a shape corresponding to the active area P, and a second adhesive portion 210B having a shape corresponding to the light-shielding region Q or the black mask 42. The second adhesive portion 210B is configured to have a higher interface reflectance than the first adhesive portion 210A. FIG. 4(B) illustrates an example of the reflectance in FIG. 4(A), and more specifically, the reflectance R of the active area. A (R A=R1+R AA +R3+R4+R5) and the reflectance of the black mask area R B (R B =R BM +R2) are roughly equal or the difference in reflectance between the two is small (R A ≒R B ), the reflectance R of the first adhesive portion 210 AA and the reflectance R of the second adhesive portion 210B BM is adjusted.

[0031] The material and thickness of the anti-reflection film 200 are not particularly limited, but for example, it is configured similarly to the first anti-reflection layer 110A in the first embodiment. The material and thickness of the first adhesive portion 210A are not particularly limited, but for example, an acrylic adhesive is used. The refractive index of the acrylic adhesive is usually 1.49, and in this case, the reflectance R of the interface with the anti-reflection film 200 is 1.49. AA is R AA The reflectance R of the interface with the anti-reflection film 200 is about 1.4. The material and thickness of the second adhesive portion 210B are not particularly limited, but for example, a silicon-based adhesive is used. The silicon-based adhesive usually has a refractive index of 1.4. BM is R BM ≒0.17%.

[0032] The first and second adhesive portions 210A, 210B can be applied to the surface of the cover glass 40 by any method, and after application, the antireflection film 200 is attached onto the first and second adhesive portions 210A, 210B. Conversely, the first and second adhesive portions 210A, 210B may be applied to the back surface of the antireflection film 200, and this may be attached to the surface of the cover glass 40.

[0033] In the second embodiment, the shield electrode 26A of the liquid crystal module 20A is made of an organic conductive film such as conductive plastic. If a metal material such as ITO is used for the shield electrode, the reflectance R3 at the interface with the glass 25 becomes high (R2 ≈ 0.7% in the example of FIG. 2) because the refractive index of ITO is high, but in the case of an organic conductive material, the refractive index is smaller than that of a metal material, and the reflectance R2 at the interface with the glass 25 can be made almost zero or almost suppressed.

[0034] When the liquid crystal display device 100A of the second embodiment is viewed from above, the reflectance R A is R A =R1(0.3%)+R AA (0.01%) + R3 (0%) + R4 (0.2%) + R5 (0.2%) = 0.71%, and the reflectance of the black mask area R B is R B =R1(0.3%)+R BM (0.17%)1 + R2 (0.2%) = 0.67%. By using an organic conductive material for the shield electrode 26A, the reflectance R3 is approximately 0%. Thus, the reflectance R A and the reflectance R of the black mask area 42 B and can be made to be equivalent.

[0035] In this way, in the second embodiment, by changing the refractive index of the adhesive material corresponding to the display area and the adhesive material corresponding to the light-shielding area, it becomes possible to use a material with a uniform refractive index, such as an anti-reflection film, and the manufacturing process can be simplified and the cost can be reduced. Also, as in the first embodiment, by eliminating the difference in reflectance between the active area P and the light-shielding area Q, it is possible to realize a seamless display in which the boundary B is not noticeable.

[0036] In the above embodiment, the liquid crystal module includes an IPS type liquid crystal panel, but the present invention is not limited to this, and the liquid crystal module may use a VA type or TN type liquid crystal panel. Also, the first embodiment and the second embodiment have been described separately, but the present invention may include a combination of the first embodiment and the second embodiment.

[0037] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes are possible within the scope of the gist of the invention described in the claims. [Explanation of symbols]

[0038] 10, 100, 100A: Liquid crystal display device 20, 20A: Liquid crystal module 21, 27: Polarizing plate 22, 25: Glass 23: TFT with AR 24: LCD panel 26, 26A: Shield electrode 30: Optical adhesive resin / optical adhesive 40: Cover glass 42: Black mask 50: Anti-reflection layer 110, 200: Anti-reflection layer 210: Adhesive material

Claims

1. A liquid crystal module; a cover glass provided on the liquid crystal module; a light-shielding region formed on the outer periphery of the rear surface of the cover glass; An anti-reflection layer formed on the front surface side of the cover glass, the antireflection layer includes a first antireflection layer corresponding to a display area for displaying an image and a second antireflection layer corresponding to the light-shielding area, A liquid crystal display device, wherein the reflectance generated on the surface of the second antireflection layer is greater than the reflectance generated on the surface of the first antireflection layer.

2. 2. The liquid crystal display device of claim 1, wherein the reflectances of the first and second anti-reflection layers are determined so that the sum of the reflectance occurring at the interface of the light-shielding region and the reflectance occurring at the surface of the second anti-reflection layer is approximately equal to the sum of the reflectance occurring at the interface of each layer in the liquid crystal module in the display region and the reflectance occurring at the surface of the first anti-reflection layer.

3. 3. The liquid crystal display device according to claim 2, wherein the reflectance occurring at the interface of each layer in the liquid crystal module includes the reflectance occurring at the interface between the sealing electrode and the glass substrate, the reflectance occurring at the interface between the glass substrate and the liquid crystal panel substrate, and the reflectance occurring at the interface between the liquid crystal panel and the TFT substrate.

4. A liquid crystal module; a cover glass provided on the liquid crystal module; a light-shielding region formed on the outer periphery of the rear surface of the cover glass; An adhesive portion formed on the front surface side of the cover glass; An anti-reflection layer formed on the adhesive portion, the adhesive portion includes a first adhesive portion corresponding to a display area for displaying an image and a second adhesive portion corresponding to the light-shielding area; a reflectance occurring at an interface between the second adhesive portion and the antireflection layer is greater than a reflectance occurring at an interface between the first adhesive portion and the antireflection layer.

5. 5. The liquid crystal display device of claim 4, wherein the reflectances of the first and second adhesive portions are determined so that the sum of the reflectance occurring at the interface of the light-shielding region, the reflectance occurring at the interface of the second adhesive portion, and the reflectance occurring at the surface of the anti-reflection layer is approximately equal to the sum of the reflectance occurring at the interfaces of each layer in the liquid crystal module in the display region, the reflectance occurring at the interface of the first adhesive portion, and the reflectance occurring at the surface of the anti-reflection layer.

6. 6. The liquid crystal display device according to claim 5, wherein the reflectance occurring at the interface of each layer in the liquid crystal module includes a reflectance occurring at the interface between a glass substrate and a liquid crystal panel substrate, and a reflectance occurring at the interface between the liquid crystal panel and the TFT substrate.

7. 7. The liquid crystal display device according to claim 6, wherein the shield electrode is made of an organic conductive film, and reflection occurring at an interface between the shield electrode and the glass substrate is suppressed.

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