Liquid crystal display device

Abstract

Provided is a liquid crystal display device in which the boundary between a display region and a light-blocking region is seamless. A liquid crystal display device (100) is provided with a liquid crystal module (20), a cover glass (40) provided on the liquid crystal module (20), a black mask (42) as a light-blocking region formed on the outer periphery of the rear surface side of the cover glass (40), and an antireflection layer (110) formed on the front surface side of the cover glass (40). The anti-reflection layer (110) includes a first anti-reflection layer (110A) corresponding to the display region and a second anti-reflection layer (110B) corresponding to the black mask (42), and the reflectivity generated on the surface of the second anti-reflection layer (110B) is greater than the reflectivity generated on the surface of the first anti-reflection layer (110A).

Description

Technical Field

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

[0002] The 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 mounted on the surface thereof. 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 for defining the light shielding area is formed on the periphery of the protective cover. The black mask is, for example, an area printed with black on the protective cover. For example, the liquid crystal display device of Patent Document 1 prevents the black mask from being conspicuous by providing an intermediate layer such as a checkered pattern on the black mask.

[0003] [Prior art literature]

[0004] [Patent Document]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-15772 Summary of the invention

[0006] Figure 1 The schematic cross section of a conventional liquid crystal display device is shown. The liquid crystal display device 10 is configured to include a liquid crystal module 20 in a housing, a cover glass 40 provided on the liquid crystal module 20 via an optical adhesive resin (OCR: optical clear film) or an optical adhesive material (OCA: optical clear adhesive) 30, and an anti-reflection layer (AR: Anti reflection) or an antistatic film (ASF: Antistatic film) 50 formed on the surface of the cover glass 40.

[0007] The liquid crystal module 20 is composed of a polarizing plate 21, a glass substrate 22, an AR substrate (TFT: Thin film transistor, AR: Array) 23 with TFT formed on the glass substrate 22, a liquid crystal panel 24 including RGB filters and liquid crystal molecules, a glass substrate 25, a shielding electrode 26, and a polarizing plate 27. In addition, a backlight (not shown) is arranged below the liquid crystal module 20.

[0008] The liquid crystal panel 24 is, for example, an IPS type in which liquid crystal molecules rotate in a direction horizontal to the panel under the action of a voltage applied via TFTs. Generally, in the IPS type, a shielding electrode 26 for releasing the electric charge charged above the liquid crystal panel 24 to GND (reference potential) is arranged between the glass substrate 25 and the polarizing plate 27. The shielding electrode 26 is made of a transparent metal material that transmits light, such as ITO.

[0009] A black mask 42 is formed around the outer periphery of the cover glass 40 so as to surround an active area for displaying an image. The black mask 42 is formed by, for example, screen-printing a black pigment on the bottom surface of the cover glass 40, and defines a light-shielding area.

[0010] In such a liquid crystal display device 10 , the following reflection occurs due to light from above (that is, when the liquid crystal display device is viewed from above), the reflectivity of the surface, and the reflectivity of the interface between the layers.

[0011] R1: Reflection on the surface of the anti-reflection film / antistatic film 50, reflectivity = about 0.3%,

[0012] R2: Reflection of the interface of the black mask region 42, reflectivity = about 0.2%

[0013] R3: Reflection at the interface between the shielding electrode 26 and the glass substrate 25, reflectivity = about 0.7%

[0014] R4: Reflection at the interface between the glass substrate 25 and the liquid crystal panel 24, reflectivity = about 0.2%

[0015] R5: Reflection at the interface between the liquid crystal panel 24 and the TFT 23, reflectivity = about 0.2%

[0016] In addition, since the refractive index of the polarizing plate, OCA, and glass is approximately 1.5, reflection at the interface due to the refractive index difference hardly occurs.

[0017] The reflectivity R of the active area A For R A =R1+R3+R4+R5≈1.4%, the reflectivity of the black mask area R B For R B =R1+R2≈0.5%, the reflectivity of the active area R A Higher reflectivity R than the black mask area B In the past, in order to make the boundary less visible, the reflectivity R of the black mask area was increased. B , or reduce the reflectivity R of the active area A , or a method of changing the reflectivity of the two.

[0018] However, in the conventional method, in order to increase the reflectivity R B , the pigment was adjusted, but due to reliability, color material constraints and other reasons, pigment adjustment has a limit and cannot significantly improve the reflectivity. On the other hand, in order to reduce the reflectivity R of the active area AIt is also possible to change the metal material (eg, ITO) of the shielding electrode 26 to an organic conductive material (eg, conductive plastic, etc.), but in this case, the resistance value of the shielding electrode 26 becomes higher, and the discharge of the charge caused by ESD (Electrical Static Discharge) may become insufficient.

[0019] The present invention is to solve such conventional technical problems, and an object of the present invention is to provide a liquid crystal display device that realizes a seamless boundary between a display area for displaying an image and a light shielding area.

[0020] The liquid crystal display device of the present invention comprises a liquid crystal module, a cover glass arranged on the liquid crystal module, a light-shielding region formed on the outer periphery of the back side of the cover glass, and an anti-reflection layer formed on the surface side of the cover glass, wherein the anti-reflection layer comprises a first anti-reflection layer corresponding to a display region for displaying an image and a second anti-reflection layer corresponding to the light-shielding region, and the reflectivity generated on the surface of the second anti-reflection layer is greater than the reflectivity generated on the surface of the first anti-reflection layer.

[0021] In one embodiment, the reflectivity of the first anti-reflection layer and the second anti-reflection layer is determined so that the sum of the reflectivity generated at the interface of the light shielding area and the reflectivity generated at the surface of the second anti-reflection layer is substantially equal to the sum of the reflectivity generated at the interface of each layer in the liquid crystal module in the display area and the reflectivity generated at the surface of the first anti-reflection layer. In one embodiment, the reflectivity generated at the interface of each layer in the liquid crystal module includes the reflectivity generated at the interface of the sealing electrode and the glass substrate, the reflectivity generated at the interface of the glass substrate and the liquid crystal panel substrate, and the reflectivity generated at the interface of the liquid crystal panel and the TFT substrate.

[0022] Furthermore, the liquid crystal display device of the present invention comprises a liquid crystal module, a cover glass arranged on the liquid crystal module, a shading area formed on the periphery of the back side of the cover glass, an adhesive portion formed on the surface side of the cover glass, and an anti-reflection layer formed on the adhesive portion, the adhesive portion comprising a first adhesive portion corresponding to a display area for displaying an image and a second adhesive portion corresponding to the shading area, and a reflectivity generated at an interface between the second adhesive portion and the anti-reflection layer is greater than a reflectivity generated at an interface between the first adhesive portion and the anti-reflection layer.

[0023] In one embodiment, the reflectivity of the first adhesive portion and the second adhesive portion is determined so that the sum of the reflectivity generated at the interface of the light shielding area, the reflectivity generated at the interface of the second adhesive portion, and the reflectivity generated on the surface of the anti-reflection layer is substantially equal to the sum of the reflectivity generated at the interface of each layer in the liquid crystal module in the display area, the reflectivity generated at the interface of the first adhesive portion, and the reflectivity generated on the surface of the anti-reflection layer. In one embodiment, the reflectivity generated at the interface of each layer in the liquid crystal module includes the reflectivity generated at the interface of the glass substrate and the liquid crystal panel substrate, and the reflectivity generated at the interface of the liquid crystal panel and the TFT substrate. In one embodiment, the shielding electrode is composed of an organic conductive film to suppress reflection generated at the interface of the sealing electrode and the glass substrate.

[0024] [Effects of the invention]

[0025] According to the present invention, by making the reflectivity generated on the surface of the second anti-reflection layer corresponding to the light-shielding area greater than the reflectivity generated on the surface of the first anti-reflection layer corresponding to the display area, the reflectivity difference between the light-shielding area and the display area can be reduced, and the boundary between the light-shielding area and the display area can be seamless and inconspicuous. Furthermore, according to the present invention, by making the reflectivity generated on the interface of the second adhesive portion corresponding to the light-shielding area greater than the reflectivity generated on the interface of the first adhesive portion corresponding to the display area, the reflectivity difference between the light-shielding area and the display area can be reduced, and the boundary between the light-shielding area and the display area can be seamless and inconspicuous. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a cross-sectional view schematically showing the structure of a conventional liquid crystal display device.

[0027] Figure 2 (A) is a schematic top view of a liquid crystal display device according to a first embodiment of the present invention. Figure 2 (B) is a schematic cross-sectional view taken along line AA.

[0028] Figure 3 It is a cross-sectional view showing an example of the manufacturing process of the antireflection layer in the first embodiment.

[0029] Figure 4 It is a schematic cross-sectional view of a liquid crystal display device according to a second embodiment of the present invention. DETAILED DESCRIPTION

[0030] The present invention is applicable not only to a liquid crystal display device having a normal image display function, but also to a liquid crystal display device equipped with a touch panel function as a user interface, and a liquid crystal display device equipped with a function of detecting the approach of a user's finger or the like using infrared rays or the like.

[0031] [Example]

[0032] Next, embodiments of the present invention will be described with reference to the accompanying drawings. The scales of the drawings are exaggerated to facilitate understanding of the invention and do not necessarily represent the scales of actual products.

[0033] Figure 2 (A) is a schematic top view of a liquid crystal display device according to a first embodiment of the present invention. Figure 2 (B) is a schematic cross-sectional view when cut along line AA. Figure 2 As shown in (A), the liquid crystal display device 100 of this embodiment is configured to accommodate a backlight or a liquid crystal module 200 in a roughly rectangular housing. When the liquid crystal display device 100 is observed from above, it has a rectangular active area (display area) P that displays an image and a shading area Q surrounding the periphery of the active area P. The shading area Q is a non-display area where no image is displayed. In the case where a touch panel is mounted in the liquid crystal display device 100, the active area P is also an area where touch operations can be performed. The dotted line B virtually represents the boundary between the active area P and the shading area Q, but in reality, such a boundary B cannot be visually recognized, or even if it can be visually recognized, it is almost inconspicuous.

[0034] like Figure 2 As shown in (B), the liquid crystal display device 100 includes a liquid crystal module 20. The liquid crystal module 20 and Figure 1 The liquid crystal module 20 shown is similarly constructed, that is, the liquid crystal module 20 is constructed by stacking, from the bottom, a polarizing plate 21, a glass substrate 22, an AR substrate (TFT: Thin film transistor, AR: Array) 23 with TFT formed on the glass substrate 22, a liquid crystal panel 24 including RGB filters and liquid crystal molecules, a glass substrate 25, a shielding 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 the horizontal direction with the panel by a voltage applied via the TFT.

[0035] A cover glass (protective glass) 40 is attached to the polarizing plate 27 of the liquid crystal panel 20 via an optical adhesive resin (OCR) or an optical adhesive material (OCA) 30. A black mask 42 defining a light shielding region Q is formed on the back side of the cover glass 40 by screen printing or the like.

[0036] An anti-reflection layer 110 is formed on the 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 region P and a second anti-reflection layer 110B having a shape corresponding to the black mask 42 or the light shielding region Q. The second anti-reflection layer 110B is configured to have a surface reflectance greater than that of the first anti-reflection layer 110A. More specifically, the reflectance R of the active region is 1 / 2. A (R A =R1+R3+R4+R5) and the reflectivity R of the black mask area B (R B =R BM +R2) or in a manner that the difference in reflectivity between the two is reduced (R A ≈R B ), adjusting the reflectivity R1 of the first anti-reflection layer 110A and the reflectivity R2 of the second anti-reflection layer 110B BM .

[0037] The cover glass 40 usually has a reflectivity of 3% to 4%, but its reflectivity is reduced by forming the anti-reflection layer 110. The first anti-reflection layer 110A is not particularly limited in terms of its material and film thickness, but is composed of a single-layer film or a multi-layer film. In the case of a multi-layer film, for example, a low-refractive material (such as MgF2, SiO2, Al2O3, etc.) and a high-refractive material (such as ZrO2, CeO2, ZnS, etc.) are alternately stacked, so that a high reflectivity reduction can be obtained. The first anti-reflection layer 110A is formed, for example, by evaporating, sputtering, or coating a material on the surface of the cover glass 40. For example, the reflectivity of the surface of the first anti-reflection layer 110A is about Figure 1 Similarly, in the antireflection layer of the liquid crystal display device 10, R1≈0.3%.

[0038] The second anti-reflection layer 110B is not particularly limited in terms of material and thickness, and may be made of, for example, a resin or coating of hollow nano-silica. For example, when the reflectivity R1 of the first anti-reflection layer 110A is ≈ 0.3%, the reflectivity R2 of the second anti-reflection layer 110B is ≈ 0.3%. BM For R BM ≈1.2%.

[0039] Figure 3 An example of a method for manufacturing the first anti-reflection layer 110A and the second anti-reflection layer 110B is shown. Figure 3 As shown in (A), a mask member 120 patterned in such a manner as to expose the active region P is formed on the cover glass 40, and then, as shown in Figure 3 As shown in (B), a material for forming the first anti-reflection layer 110A is deposited in the region exposed by the mask member 120. Figure 3 As shown in (C), after removing the mask part 120, as shown in Figure 3As shown in (D), a material for forming a second anti-reflection layer 110B is applied to the region surrounding the first anti-reflection layer 110A. Thus, an anti-reflection layer 110 having two anti-reflection layers with different reflectivities, namely, a first anti-reflection layer 110A corresponding to the active region P and a second anti-reflection layer 110B corresponding to the light shielding region Q, is formed on the cover glass 40.

[0040] In the liquid crystal display device 100 configured in this way, the reflectivity when viewed from above is determined by the reflectivity of the surface and the reflectivity of the interface. A For R A = R1 (0.3%) + R3 (0.7%) + R4 (0.2%) + R5 (0.2%) = 1.4%. On the other hand, the reflectivity R B For R B =R BM (1.2%)1+R2(0.2%)=1.4%, the reflectivity of the active area R A and the reflectivity R of the black mask area B In this way, by eliminating the reflectivity difference between the active region P and the black mask region, the boundary B between the active region P and the light shielding region Q can be made inconspicuous, and the boundary B can be made seamless.

[0041] Next, the second embodiment of the present invention is 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, but in the second embodiment, an adhesive material having different refractive indices is formed on the cover glass 40, and the anti-reflection layer is formed thereon.

[0042] Figure 4 is a cross-sectional view showing a schematic structure of a liquid crystal display device according to a second embodiment. Figure 2 The same structures as shown are marked with the same reference numerals. Figure 4 As shown in FIG. 2 (A), in the liquid crystal display device 100A of the second embodiment, a film-like antireflection film 200 is attached to the surface of the cover glass 40 via an adhesive material 210 .

[0043] The adhesive material 210 includes a first adhesive portion 210A having a shape corresponding to the active region 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 greater reflectivity at the interface than the first adhesive portion 210A. Figure 4 (B) is in Figure 4 (A) shows an example of a reflectivity graph, more specifically, the reflectivity R of the active area. A (R A =R1+R AA +R3+R4+R5) and the reflectivity R of the black mask areaB (R B =R BM +R2) is approximately equal or the difference in reflectivity between the two is reduced (R A ≈R B ), adjusting the reflectivity R of the first adhesive portion 210 AA The reflectivity R of the second adhesive portion 210B BM .

[0044] The material and thickness of the anti-reflection film 200 are not particularly limited, and can be, for example, configured in the same manner as the first anti-reflection layer 110A in the first embodiment. The material and thickness of the first adhesive portion 210A are not particularly limited, and can be, for example, an acrylic adhesive. The acrylic adhesive generally has a refractive index of 1.49. In this case, the reflectivity R of the interface with the anti-reflection film 200 is 1.49. AA For R AA ≈0.01%. The material and thickness of the second adhesive part 210B are not particularly limited, and for example, a silicon-based adhesive material can be used. The silicon-based adhesive material generally has a refractive index of 1.4. In this case, the reflectivity R of the interface with the anti-reflection film 200 is BM For R BM ≈0.17%.

[0045] The first and second adhesive portions 210A and 210B can be applied to the surface of the cover glass 40 by any method, and after application, the anti-reflection film 200 is attached to the first and second adhesive portions 210A and 210B. Conversely, the first and second adhesive portions 210A and 210B can be applied to the back surface of the anti-reflection film 200 and attached to the surface of the cover glass 40.

[0046] In the second embodiment, the shielding electrode 26A of the liquid crystal module 20A is formed of an organic conductive film such as conductive plastic. When a metal material such as ITO is used for the shielding electrode, the refractive index of ITO is high, so the reflectivity R3 of the interface with the glass substrate 25 becomes high (at Figure 2 In the example, R2≈0.7%), in the case of an organic conductive material, the refractive index becomes smaller than that of a metal material, and the reflectivity R2 of the interface with the glass substrate 25 can be roughly suppressed to be substantially zero.

[0047] When the liquid crystal display device 100A of the second embodiment is viewed from above, the reflectivity R of the active region is A For R A =R1(0.3%)+R AA (0.01%) + R3 (0%) + R4 (0.2%) + R5 (0.2%) = 0.71%, the reflectivity of the black mask area R B For R B =R1(0.3%)+RBM (0.17%)1+R2(0.2%)=0.67%. By making the shielding electrode 26A an organic conductive material, the reflectivity R3≈0%. In this way, the reflectivity R A and the reflectivity R of the black mask area 42 B to the same extent.

[0048] Thus, 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, a material having a uniform refractive index such as an anti-reflection film can be used, and the manufacturing process can be simplified and the cost can be reduced. In addition, similarly to the first embodiment, by eliminating the reflectivity difference between the active area P and the light shielding area Q, a seamless interface can be achieved in which the boundary B is not noticeable.

[0049] In addition, in the above-mentioned embodiment, an example of a liquid crystal module including an IPS type liquid crystal panel is illustrated, but the present invention is not limited thereto, and a liquid crystal module may also use a VA type or TN type liquid crystal panel. In addition, the first embodiment and the second embodiment are described separately, but the present invention may also include a combination of the first embodiment and the second embodiment.

[0050] As mentioned above, although the preferred embodiment of the present invention is described in detail, the present invention is not limited to the specific embodiment, and various modifications and changes can be made within the scope of the gist of the invention described in the claims.

[0051] [Explanation of Reference Numerals]

[0052] 10, 100, 100A: liquid crystal display device 20, 20A: liquid crystal module

[0053] 21, 27: Polarizing plate 22, 25: Glass

[0054] 23: TFT with AR 24: LCD panel

[0055] 26, 26A: shielding electrode 30: optical bonding resin / optical bonding material

[0056] 40: Cover glass 42: Black mask

[0057] 50: Anti-reflection layer 110, 200: Anti-reflection layer

[0058] 210: Adhesive material

Claims

1. A liquid crystal display device comprising: LCD module; A cover glass disposed on the liquid crystal module; a light shielding region formed on the outer periphery of the back side of the cover glass; and an antireflection layer formed on the surface side of the cover glass, The anti-reflection layer includes 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. The reflectivity generated on the surface of the second antireflection layer is higher than the reflectivity generated on the surface of the first antireflection layer.

2. The liquid crystal display device according to claim 1, wherein: The reflectivity of the first anti-reflection layer and the second anti-reflection layer is determined in such a way that the sum of the reflectivity generated at the interface of the shading area and the reflectivity generated at the surface of the second anti-reflection layer is approximately equal to the sum of the reflectivity generated at the interface of each layer in the liquid crystal module in the display area and the reflectivity generated at the surface of the first anti-reflection layer.

3. The liquid crystal display device according to claim 2, wherein: The reflectivity generated at the interfaces of the layers in the liquid crystal module includes the reflectivity generated at the interface between the sealing electrode and the glass substrate, the reflectivity generated at the interface between the glass substrate and the liquid crystal panel substrate, and the reflectivity generated at the interface between the liquid crystal panel and the TFT substrate.

4. A liquid crystal display device comprising: LCD module; A cover glass disposed on the liquid crystal module; a light shielding region formed on the outer periphery of the back side of the cover glass; an adhesive portion formed on the surface side of the cover glass; and an antireflection 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. The reflectivity generated at the interface between the second adhesive portion and the anti-reflection layer is greater than the reflectivity generated at the interface between the first adhesive portion and the anti-reflection layer.

5. The liquid crystal display device according to claim 4, wherein: The reflectivity of the first anti-reflection layer and the second anti-reflection layer is determined in such a manner that the sum of the reflectivity generated at the interface of the shading area, the reflectivity generated at the interface of the second adhesive portion, and the reflectivity generated on the surface of the anti-reflection layer is approximately equal to the sum of the reflectivity generated at the interfaces of each layer in the liquid crystal module in the display area, the reflectivity generated at the interface of the first adhesive portion, and the reflectivity generated on the surface of the anti-reflection layer.

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

7. The liquid crystal display device according to claim 6, wherein: The shielding electrode is formed of an organic conductive film and suppresses reflection generated at the interface between the sealing electrode and the glass substrate.

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