A color cholesteric liquid crystal display device

Abstract

The utility model discloses a kind of colour cholesteric liquid crystal display devices, including blue display module, green display module and red display module from top to bottom are sequentially arranged, and the side of red display module away from green display module is equipped with light-absorbing layer, by increasing photoexcitation material or photoluminescent layer in display device, red, green light is generated by using the part of blue light that is not reflected, to make up the problem of insufficient red, green reflectivity of lower layer of three-layer colour cholesteric liquid crystal display structure, improve overall reflectivity, while solve the problem of white picture blue when displaying.

Description

Technical Field

[0001] This utility model relates to the field of cholesteric liquid crystal display technology, and in particular to a color cholesteric liquid crystal display device. Background Technology

[0002] Cholesteric liquid crystal electronic paper relies on a twisted cholesteric liquid crystal layer to reflect light of a specific wavelength and on the bistable property of the cholesteric liquid crystal to maintain the image even after power loss. Common single-layer cholesteric display device structures include... Figure 1 As shown, the display includes upper and lower substrates and a liquid crystal layer between them. Electrodes are provided on the surfaces of both the upper and lower substrates. By applying different pulse voltages to the liquid crystal layer through the upper and lower electrodes, two stable states can be achieved: a planar state (P-state) and a focal conic state (FC-state). When the cholesteric liquid crystal layer is in the FC-state, external light entering the display is absorbed by the bottom black ink, displaying black. When the cholesteric liquid crystal layer is in the P-state, the cholesteric liquid crystal layer reflects light of the corresponding wavelength, and the remaining light passing through the cholesteric liquid crystal layer is also completely absorbed by the bottom black ink layer.

[0003] Adjusting the pitch of the cholesteric liquid crystal allows for the reflection of different colors of light, such as red, green, and blue. Cholesteric liquid crystal displays typically employ a three-layer stacking method to achieve full-color display. Cholesteric liquid crystal displays generally use a blue, green, and red sequence to form the three-layer display module, with a light-absorbing layer coated on the bottom red cholesteric liquid crystal cell side. The molecules of cholesteric liquid crystals are arranged in a helical shape, and depending on the direction of the helix, they can be classified as left-handed or right-handed. Cholesteric liquid crystals only reflect light with the same helical direction as their own structure; light with the other helix direction passes through the liquid crystal layer without reflection. The other helix direction of blue, green, and red light passes through the lower medium sequentially and is ultimately absorbed by the light-absorbing layer. In reflective mode, such as... Figure 2 As shown, green and red reflected light are affected by the layers of media above, resulting in a decrease in reflectivity. Since the reflectivity of red light is less than that of green light, which is less than that of blue light, this leads to an overall low reflectivity of the display screen, and also causes a bluish tint to white images. Utility Model Content

[0004] To address the technical problems existing in the background art, this utility model proposes a color cholesteric liquid crystal display device.

[0005] The present invention proposes a color cholesteric liquid crystal display device, comprising a blue display module, a green display module and a red display module arranged sequentially from top to bottom;

[0006] The blue display module includes a first upper substrate, a first lower substrate, and a blue cholesteric liquid crystal layer sandwiched between the two. The green display module includes a second upper substrate, a second lower substrate, and a green cholesteric liquid crystal layer sandwiched between the two. The red display module includes a third upper substrate, a third lower substrate, and a red cholesteric liquid crystal layer sandwiched between the two. A light-absorbing layer is provided on the side of the red display module away from the green display module.

[0007] A green excitation material is disposed between the blue cholesteric liquid crystal layer and the green cholesteric liquid crystal layer. The green excitation material generates green light when excited by blue light.

[0008] And / or, a red excitation material is provided between the green cholesteric liquid crystal layer and the red cholesteric liquid crystal layer, and the red excitation material generates red light when excited by blue light.

[0009] Preferably, a first OCA layer is provided between the first lower substrate and the second upper substrate, and a second OCA layer is provided between the second lower substrate and the third upper substrate.

[0010] Preferably, the green excitation material is located within the first OCA layer, and the red excitation material is located within the second OCA layer.

[0011] Preferably, a green excitation material layer is provided between the second upper substrate and the green cholesteric liquid crystal layer.

[0012] Preferably, a red excitation material layer is provided between the third upper substrate and the red cholesteric liquid crystal layer.

[0013] Preferably, the green excitation material and / or the red excitation material are fluorescent materials or quantum dot materials.

[0014] Preferably, the emission wavelength range of the green excitation material is the same as the liquid crystal reflection wavelength of the green cholesteric liquid crystal layer, and the emission wavelength range of the red excitation material is the same as the liquid crystal reflection wavelength of the red cholesteric liquid crystal layer.

[0015] This utility model also proposes a color cholesteric liquid crystal display device, including a blue display module, a green display module and a red display module arranged sequentially from top to bottom;

[0016] The blue display module includes a first upper substrate, a first lower substrate, and a blue cholesteric liquid crystal layer sandwiched between the two. The green display module includes a second upper substrate, a second lower substrate, and a green cholesteric liquid crystal layer sandwiched between the two. The red display module includes a third upper substrate, a third lower substrate, and a red cholesteric liquid crystal layer sandwiched between the two. A light-absorbing layer is provided on the side of the red display module away from the green display module.

[0017] The green cholesteric liquid crystal layer contains a green excitation material, which generates green light when excited by blue light; and / or, the red cholesteric liquid crystal layer contains a red excitation material, which generates red light when excited by blue light.

[0018] The proposed color cholesteric liquid crystal display device includes a blue display module, a green display module, and a red display module arranged sequentially from top to bottom. The red display module has a light-absorbing layer on the side away from the green display module. By adding a photoexcitation material or a photoluminescent layer inside the display device, red and green light are generated by exciting the unreflected blue light, thereby compensating for the insufficient red and green reflectivity of the lower layer of the three-layer color cholesteric liquid crystal display structure, improving the overall reflectivity, and solving the problem of the white screen appearing bluish during display. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a prior art color cholesteric liquid crystal display device.

[0020] Figure 2 This is a reflectance spectrum of a prior art color cholesteric liquid crystal display device.

[0021] Figure 3 This is a schematic diagram of one embodiment of a color cholesteric liquid crystal display device proposed in this utility model.

[0022] Figure 4 This is a schematic diagram of another embodiment of the color cholesteric liquid crystal display device proposed in this utility model.

[0023] Figure 5 This is a schematic diagram of another embodiment of the color cholesteric liquid crystal display device proposed in this utility model.

[0024] Figure 6 for Figure 5 The reflectance spectrum of a color cholesteric liquid crystal display device. Detailed Implementation

[0025] Reference Figure 3 and 4 The present invention proposes a color cholesteric liquid crystal display device, comprising a blue display module, a green display module and a red display module arranged sequentially from top to bottom;

[0026] The blue display module includes a first upper substrate 11, a first lower substrate 12 and a blue cholesteric liquid crystal layer 13 sandwiched between the two; the green display module includes a second upper substrate 21, a second lower substrate 22 and a green cholesteric liquid crystal layer 23 sandwiched between the two; the red display module includes a third upper substrate 31, a third lower substrate 32 and a red cholesteric liquid crystal layer 33 sandwiched between the two; and a light-absorbing layer 4 is provided on the side of the red display module away from the green display module.

[0027] A green excitation material is disposed between the blue cholesteric liquid crystal layer 13 and the green cholesteric liquid crystal layer 23. The green excitation material generates green light when excited by blue light.

[0028] A red excitation material is disposed between the green cholesteric liquid crystal layer 23 and the red cholesteric liquid crystal layer 33. The red excitation material generates red light when excited by blue light.

[0029] In the specific operation of the color cholesteric liquid crystal display device of this embodiment, by applying different pulse voltages to the liquid crystal layer through the upper and lower electrodes, two stable states can be achieved: a planar state (P-state) and a focal conic state (FC-state). When the cholesteric liquid crystal layer is in the FC-state, external light entering the display screen is absorbed by the bottom black ink, displaying black. When the cholesteric liquid crystal layer is in the P-state, the cholesteric liquid crystal layer reflects light of the corresponding wavelength, and the remaining light passing through the cholesteric liquid crystal layer is also completely absorbed by the bottom black ink layer. Since the molecules of cholesteric liquid crystal are arranged in a helical shape, single-layer liquid crystals can be divided into left-handed and right-handed helical depending on the direction of the helix. Cholesteric liquid crystals only reflect the portion of light with the same helix direction as their own structure, while light with the other helix direction passes through the liquid crystal layer without reflection. Therefore, the blue light component in the incident light passes through the blue cholesteric liquid crystal layer, and the blue light with one helix direction is reflected normally, while the blue light with the other helix direction passes through the blue liquid crystal layer and enters the display module below. The green excitation material generates green light after being excited by blue light, which enhances the green incident light of the green liquid crystal layer and improves its green light reflection effect. Similarly, the red excitation material generates red light after being excited by blue light, which enhances the red incident light of the red liquid crystal layer and improves its red light reflection effect.

[0030] In this embodiment, the proposed color cholesteric liquid crystal display device includes a blue display module, a green display module, and a red display module arranged sequentially from top to bottom. The red display module has a light-absorbing layer on the side away from the green display module. By adding a photoexcitation material or a photoluminescent layer inside the display device, red and green light are generated by exciting the unreflected blue light, thereby compensating for the insufficient red and green reflectivity of the lower layer of the three-layer color cholesteric liquid crystal display structure, improving the overall reflectivity, and solving the problem of the white screen appearing bluish during display.

[0031] In the selection of excitation materials, fluorescent materials or quantum dot materials are used for green excitation materials and / or red excitation materials.

[0032] Reference Figure 3 In one specific embodiment, in order to reduce light loss between the lower substrate of the upper display module and the upper substrate of the lower display module, a first OCA layer 51 is provided between the first lower substrate 12 and the second upper substrate 21, and a second OCA layer 52 is provided between the second lower substrate 22 and the third upper substrate 31. The upper and lower modules are bonded together by OCA optical adhesive to reduce the influence of the refractive index of the air-substrate interface on light.

[0033] Furthermore, the green excitation material is located within the first OCA layer 51, and the red excitation material is located within the second OCA layer 52. The excitation materials can be directly added to the OCA layer above the corresponding liquid crystal layer. When the green excitation material in the first OCA layer is excited by blue light, it radiates green light; when the red excitation material in the second OCA layer is excited by blue light, it radiates red light. The radiated green and red light are reflected by the green cholesteric liquid crystal layer and the red cholesteric liquid crystal layer, respectively, thus increasing the reflectivity of the green and red light.

[0034] Reference Figure 4 In another specific embodiment, a green excitation material layer 61 is provided between the second upper substrate 21 and the green cholesteric liquid crystal layer 23. A red excitation material layer 62 is provided between the third upper substrate 31 and the red cholesteric liquid crystal layer 33. Alternatively, the excitation material layer can be coated on the inner side of the substrate of the display module. Specifically, the excitation wavelengths of the green and red excitation materials are in the range of 250-480 nm. The photoluminescence wavelength of the green excitation material is in the range of 480-600 nm, which is the same as the reflection wavelength range of the green cholesteric liquid crystal. The photoluminescence wavelength of the red excitation material is in the range of 600-720 nm, which is the same as the reflection wavelength range of the red cholesteric liquid crystal.

[0035] Reference Figure 5 and 6 This embodiment also proposes a color cholesteric liquid crystal display device, including a blue display module, a green display module and a red display module arranged sequentially from top to bottom;

[0036] The blue display module includes a first upper substrate 11, a first lower substrate 12 and a blue cholesteric liquid crystal layer 13 sandwiched between the two; the green display module includes a second upper substrate 21, a second lower substrate 22 and a green cholesteric liquid crystal layer 23 sandwiched between the two; the red display module includes a third upper substrate 31, a third lower substrate 32 and a red cholesteric liquid crystal layer 33 sandwiched between the two; and a light-absorbing layer 4 is provided on the side of the red display module away from the green display module.

[0037] The green cholesteric liquid crystal layer 23 contains a green excitation material, which generates green light when excited by blue light; and / or, the red cholesteric liquid crystal layer 33 contains a red excitation material, which generates red light when excited by blue light.

[0038] In practice, the excitation material can also be directly mixed into the corresponding liquid crystal layer, with the content of the excitation material ranging from 0.1 to 5 wt%.

[0039] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A color cholesteric liquid crystal display device, characterized in that, It includes a blue display module, a green display module, and a red display module arranged from top to bottom; The blue display module includes a first upper substrate (11), a first lower substrate (12) and a blue cholesteric liquid crystal layer (13) sandwiched between the two. The green display module includes a second upper substrate (21), a second lower substrate (22) and a green cholesteric liquid crystal layer (23) sandwiched between the two. The red display module includes a third upper substrate (31), a third lower substrate (32) and a red cholesteric liquid crystal layer (33) sandwiched between the two. A light-absorbing layer (4) is provided on the side of the red display module away from the green display module. A green excitation material is provided between the blue cholesteric liquid crystal layer (13) and the green cholesteric liquid crystal layer (23), and the green excitation material generates green light when excited by blue light; And / or, a red excitation material is provided between the green cholesteric liquid crystal layer (23) and the red cholesteric liquid crystal layer (33), and the red excitation material generates red light when excited by blue light.

2. The color cholesteric liquid crystal display device according to claim 1, characterized in that, A first OCA layer (51) is provided between the first lower substrate (12) and the second upper substrate (21), and a second OCA layer (52) is provided between the second lower substrate (22) and the third upper substrate (31).

3. The color cholesteric liquid crystal display device according to claim 2, characterized in that, The green excitation material is located in the first OCA layer (51), and the red excitation material is located in the second OCA layer (52).

4. The color cholesteric liquid crystal display device according to claim 1, characterized in that, A green excitation material layer (61) is provided between the second upper substrate (21) and the green cholesteric liquid crystal layer (23).

5. The color cholesteric liquid crystal display device according to claim 1, characterized in that, A red excitation material layer (62) is provided between the third upper substrate (31) and the red cholesteric liquid crystal layer (33).

6. The color cholesteric liquid crystal display device according to claim 1, characterized in that, Green and / or red excitation materials are made of fluorescent or quantum dot materials.

7. The color cholesteric liquid crystal display device according to claim 1, characterized in that, The emission wavelength range of the green excitation material is the same as the liquid crystal reflection wavelength of the green cholesteric liquid crystal layer (23), and the emission wavelength range of the red excitation material is the same as the liquid crystal reflection wavelength of the red cholesteric liquid crystal layer (33).

8. A color cholesteric liquid crystal display device, characterized in that, It includes a blue display module, a green display module, and a red display module arranged from top to bottom; The blue display module includes a first upper substrate (11), a first lower substrate (12) and a blue cholesteric liquid crystal layer (13) sandwiched between the two. The green display module includes a second upper substrate (21), a second lower substrate (22) and a green cholesteric liquid crystal layer (23) sandwiched between the two. The red display module includes a third upper substrate (31), a third lower substrate (32) and a red cholesteric liquid crystal layer (33) sandwiched between the two. A light-absorbing layer (4) is provided on the side of the red display module away from the green display module. The green cholesteric liquid crystal layer (23) contains a green excitation material, which generates green light when excited by blue light; and / or, the red cholesteric liquid crystal layer (33) contains a red excitation material, which generates red light when excited by blue light.

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