Cholesterol liquid crystal display device

Abstract

The utility model provides a cholesterol liquid crystal display device. The cholesterol liquid crystal display device comprises a plurality of stacked cholesterol liquid crystal modules and a light absorption layer arranged at the bottommost part. Each of the plurality of cholesterol liquid crystal modules includes a cholesterol liquid crystal layer and at least one photo-alignment layer. The cholesterol liquid crystal layer comprises a plurality of pixels, and the optical alignment layer is arranged on the cholesterol liquid crystal layer. The optical alignment layer of one of the plurality of cholesteric liquid crystal modules provides an alignment direction for the pixels of the one of the plurality of cholesteric liquid crystal modules, and the optical alignment layer of another one of the plurality of cholesteric liquid crystal modules provides another alignment direction for the pixels of another one of the plurality of cholesteric liquid crystal modules. The alignment direction is different from the other alignment direction. Therefore, the uniformity of the reflectivity under different visual angles can be effectively improved.

Description

Technical Field

[0001] This disclosure relates to a display device, and more particularly to a cholesteric liquid crystal display device using a photoalignment process. Background Technology

[0002] The photoelectric properties of Cholesteric Liquid Crystal Displays (ChLCDs) are closely related to the alignment technology of the liquid crystals. Contact alignment technologies, such as rubbing alignment, utilize lint to rub the alignment film. After being rubbed, the long chains on the alignment film surface provide regular and directional surface energy, driving the liquid crystal molecules to align regularly along the direction of friction. However, rubbing alignment is a destructive process; the friction between the lint and the alignment film surface easily causes bright and dark spots, scratches, and electrostatic discharge, resulting in poor product quality. Furthermore, another problem with rubbing alignment is that the reflected light from cholesteric liquid crystals has a focusing effect, causing ambient light to be concentrated at the positive viewing angle. Therefore, this can easily lead to uneven reflectivity of cholesteric liquid crystals at different viewing angles in image display.

[0003] Non-contact alignment technologies, such as photo-alignment, involve coating a photosensitive material onto the substrate of a liquid crystal display (LCD) and then irradiating it with ultraviolet light. Upon illumination, the photosensitive material undergoes a change in its molecular structure, forming a specific microstructure or molecular orientation that guides the liquid crystal molecules to align in a particular direction. While photo-alignment reduces the defects of brush alignment, it still suffers from uneven reflectivity at different viewing angles, leading to visual defects in the display image, such as uneven brightness and color distortion. Utility Model Content

[0004] Therefore, the purpose of this disclosure is to provide a cholesteric liquid crystal display device that uses a photoalignment process to precisely control the alignment direction of the photoalignment layer on the cholesteric liquid crystal layer, and the cholesteric liquid crystal layers in different cholesteric liquid crystal modules are respectively assigned different alignment directions, thereby effectively improving the uniformity of reflectivity at different viewing angles and expanding the potential of cholesteric liquid crystal display devices in high-resolution and wide-viewing-angle display applications.

[0005] According to one embodiment of the present disclosure, a cholesteric liquid crystal display device is provided, comprising a plurality of cholesteric liquid crystal modules and a light-absorbing layer. The plurality of cholesteric liquid crystal modules are stacked on top of each other, each of the plurality of cholesteric liquid crystal modules comprising a cholesteric liquid crystal layer and at least one photoalignment layer. The cholesteric liquid crystal layer comprises a plurality of pixels. The at least one photoalignment layer is disposed on the cholesteric liquid crystal layer. The light-absorbing layer is disposed at the bottom of one of the plurality of cholesteric liquid crystal modules. The at least one photoalignment layer of one of the plurality of cholesteric liquid crystal modules selectively provides an alignment direction for at least one of the plurality of pixels of that one of the plurality of cholesteric liquid crystal modules based on a photoalignment process, and the at least one photoalignment layer of another of the plurality of cholesteric liquid crystal modules selectively provides another alignment direction for at least one of the plurality of pixels of that other of the plurality of cholesteric liquid crystal modules based on a photoalignment process.

[0006] Other embodiments of the aforementioned implementation are as follows: the number of the aforementioned at least one photoalignment layer is two, namely a first photoalignment layer and a second photoalignment layer. A cholesteric liquid crystal layer is disposed between the first photoalignment layer and the second photoalignment layer. Each of the plurality of cholesteric liquid crystal modules further includes a first transparent substrate and a second transparent substrate. The first photoalignment layer is disposed on the first transparent substrate, and the second photoalignment layer is disposed on the second transparent substrate.

[0007] Other embodiments of the aforementioned implementation are as follows: the aforementioned first photoalignment layer provides a first alignment direction for at least one of the plurality of pixels, the second photoalignment layer provides a second alignment direction for at least one of the plurality of pixels, and the first alignment direction and the second alignment direction differ by 90 degrees.

[0008] Other embodiments of the aforementioned implementation are as follows: the aforementioned alignment direction is different from the other alignment direction.

[0009] Other embodiments of the aforementioned implementation are as follows: an adhesive layer is provided between adjacent stacked cholesterol liquid crystal modules mentioned above.

[0010] Other embodiments of the aforementioned implementation are as follows: the rotation pitch of the liquid crystal molecules in each of the plurality of cholesterol liquid crystal modules described above is different.

[0011] Other embodiments of the aforementioned implementation are as follows: the liquid crystal molecules in each of the plurality of cholesterol liquid crystal modules described above have the same rotation pitch.

[0012] Other embodiments of the aforementioned implementation are as follows: the liquid crystal optical rotation of adjacent stacked cholesterol liquid crystal modules is different from that of each other.

[0013] Other embodiments of the foregoing implementation are as follows: At least one photoalignment layer of the aforementioned plurality of cholesterol liquid crystal modules includes a plurality of alignment units, each of the plurality of alignment units having a plurality of alignment directions. One of the plurality of alignment directions differs from another of the plurality of alignment directions by 45 degrees.

[0014] Other embodiments of the aforementioned implementation are as follows: the aforementioned plurality of alignment units are arranged alternately and at intervals to form a grid pattern or a stripe pattern.

[0015] Other embodiments of the aforementioned implementation are as follows: the aforementioned at least one optical alignment layer further includes an unaligned unit, which has a grid-like structure. Attached Figure Description

[0016] Figure 1 This is a schematic diagram illustrating a cholesterol liquid crystal display device in a first embodiment of the first embodiment according to the present disclosure;

[0017] Figure 2A It is a drawing Figure 1 A schematic diagram of the alignment direction of the upper liquid crystal cell in a cholesterol liquid crystal display device;

[0018] Figure 2B It is a drawing Figure 1 A schematic diagram of the alignment direction of the lower liquid crystal cell in a cholesterol liquid crystal display device;

[0019] Figure 3 This is a schematic diagram illustrating the alignment direction of the first photoalignment layer of the upper liquid crystal cell of the cholesterol liquid crystal display device in a second embodiment of the first embodiment of the present disclosure;

[0020] Figure 4 This is a schematic diagram illustrating the alignment direction of the first photoalignment layer of the upper liquid crystal cell of the cholesterol liquid crystal display device in a third embodiment of the first embodiment of the present disclosure;

[0021] Figure 5 This is a schematic diagram illustrating the alignment direction of the first photoalignment layer of the upper liquid crystal cell of the cholesterol liquid crystal display device in the fourth embodiment of the first embodiment of the present disclosure;

[0022] Figure 6 This is a schematic diagram illustrating the alignment direction of the first photoalignment layer of the upper liquid crystal cell in the fifth embodiment of the cholesterol liquid crystal display device according to the first embodiment of this disclosure; and

[0023] Figure 7 This is a flowchart illustrating a method for manufacturing a cholesterol liquid crystal display device according to a second embodiment of the present disclosure.

[0024] The reference numerals in the attached figures are explained as follows:

[0025] 10, 10a, 10b, 10c, 10d: Cholesterol LCD display device

[0026] 100, 200: Cholesterol LCD module

[0027] 101: Adhesive layer

[0028] 110, 210: First transparent substrate

[0029] 111,211: First transparent substrate

[0030] 112,212: First transparent electrode layer

[0031] 120, 220: Second transparent substrate

[0032] 121,221: Second transparent substrate

[0033] 122,222: Second transparent electrode layer

[0034] 130,230: Cholesterol liquid crystal layer

[0035] 141, 141a, 141b, 141c, 141d, 241: First photoalignment layer

[0036] 142,242: Second photoalignment layer

[0037] 20: Manufacturing method of cholesterol liquid crystal display device

[0038] 300: Light Absorption Layer

[0039] D1, D3: First alignment direction

[0040] D2, D4: Second alignment direction

[0041] S01, S02, S03, S04: Steps

[0042] U1: First Alignment Unit

[0043] U2: Second Alignment Unit

[0044] U3: Third Alignment Unit

[0045] U4: Fourth Alignment Unit

[0046] UN: Non-alignment unit Detailed Implementation

[0047] Several embodiments of this disclosure will be described below with reference to the accompanying drawings. For clarity, many practical details will be set forth in the following description. However, it should be understood that these practical details should not be used to limit the scope of this disclosure. That is, in some embodiments of this disclosure, these practical details are not essential. Furthermore, for the sake of simplicity, some conventional structures and elements will be illustrated in the drawings in a simple schematic manner; and repeated elements may be denoted by the same reference numerals.

[0048] Furthermore, in this document, when a component (or unit or module, etc.) is "connected / linked" to another component, it can mean that the component is directly connected / linked to the other component, or it can mean that the component is indirectly connected / linked to the other component, that is, there is another component between the component and the other component. Only when it is explicitly stated that a component is "directly connected / linked" to another component does it mean that there is no other component between the component and the other component. The terms "first," "second," and "third" are only used to describe different components and do not limit the components themselves; therefore, "first component" can also be referred to as "second component." Moreover, the combinations of components / units / circuits in this document are not combinations generally known, conventional, or existing in this field. Whether the component / unit / circuit itself is existing cannot be used to determine whether its combination relationship is easily accomplished by someone of ordinary skill in the art.

[0049] Please see Figure 1 , Figure 1 This is a schematic diagram illustrating a cholesterol liquid crystal display device according to a first embodiment of the first embodiment of the present disclosure. Figure 1 As shown, the cholesteric liquid crystal display device 10 includes a plurality of cholesteric liquid crystal modules 100 and 200 and a light absorption layer 300. The cholesteric liquid crystal modules 100 and 200 are stacked on top of each other. The cholesteric liquid crystal module 100 includes a cholesteric liquid crystal layer 130 and at least one photoalignment layer, with the photoalignment layer of the cholesteric liquid crystal module 100 disposed on the cholesteric liquid crystal layer 130. The cholesteric liquid crystal module 200 includes a cholesteric liquid crystal layer 230 and at least one photoalignment layer, with the photoalignment layer of the cholesteric liquid crystal module 200 disposed on the cholesteric liquid crystal layer 230. Each of the cholesteric liquid crystal layers 130 and 230 includes a plurality of pixels. The light absorption layer 300 is disposed at the bottom of the cholesteric liquid crystal modules 100 and 200.

[0050] The photoalignment layer of the cholesteric liquid crystal module 100 selectively provides an alignment direction to at least one of the plurality of pixels of the cholesteric liquid crystal layer 130 based on a photoalignment process. The photoalignment layer of the cholesteric liquid crystal module 200 selectively provides another alignment direction to at least one of the plurality of pixels of the cholesteric liquid crystal layer 230 based on a photoalignment process. The alignment direction provided by the photoalignment layer of the cholesteric liquid crystal module 100 may be different from the other alignment direction provided by the photoalignment layer of the cholesteric liquid crystal module 200. Therefore, the cholesteric liquid crystal display device 10 of this disclosure can precisely control the photoalignment layers of the cholesteric liquid crystal modules 100 and 200 to respectively impart different alignment directions to the cholesteric liquid crystal layers 130 and 230 through a photoalignment process, thereby effectively improving the uniformity of reflectivity at different viewing angles and expanding the potential of the cholesteric liquid crystal display device 10 in high-resolution and wide-viewing-angle display applications.

[0051] In the first embodiment, the cholesteric liquid crystal module 100 may have two photoalignment layers, and these two photoalignment layers are a first photoalignment layer 141 and a second photoalignment layer 142, respectively. A cholesteric liquid crystal layer 130 is disposed between the first photoalignment layer 141 and the second photoalignment layer 142. Specifically, the cholesteric liquid crystal module 100 may further include a first transparent substrate 110 and a second transparent substrate 120. The first photoalignment layer 141 is disposed between the first transparent substrate 110 and the cholesteric liquid crystal layer 130, while the second photoalignment layer 142 is disposed between the second transparent substrate 120 and the cholesteric liquid crystal layer 130.

[0052] The first transparent substrate 110 includes a first transparent base material 111 and a first transparent electrode layer 112. The first transparent electrode layer 112 is disposed between the first transparent base material 111 and the first photoalignment layer 141. In some embodiments, the first transparent base material 111 may be, but is not limited to, a rigid substrate or a flexible substrate. The rigid substrate may be, for example, a glass plate or polymethyl methacrylate (PMMA), i.e., an acrylic plate. The flexible substrate may be, for example, a substrate made of polyimide (PI) or polyethylene terephthalate (PET). The first transparent electrode layer 112 may be made of a transparent conductive material, such as a transparent conductive oxide (TCO), a conductive polymer, or a metal thin film, for example, indium tin oxide (ITO), indium zinc oxide (IZO), poly-3,4-ethylenedioxythiophene (PEDOT), copper metal mesh film, or silver nanowire.

[0053] The second transparent substrate 120 may include a second transparent substrate 121 and a second transparent electrode layer 122. The second transparent electrode layer 122 is disposed between the second transparent substrate 121 and the second photoalignment layer 142. The material of the second transparent substrate 121 is the same as the material of the first transparent substrate 111, and the material of the second transparent electrode layer 122 is the same as the material of the first transparent electrode layer 112.

[0054] Furthermore, the internal structure of the cholesteric liquid crystal module 200 is the same as that of the cholesteric liquid crystal module 100. The cholesteric liquid crystal module 200 may have two photoalignment layers, specifically a first photoalignment layer 241 and a second photoalignment layer 242. A cholesteric liquid crystal layer 230 is disposed between the first photoalignment layer 241 and the second photoalignment layer 242. The cholesteric liquid crystal module 200 may also include a first transparent substrate 210 and a second transparent substrate 220. The first photoalignment layer 241 is disposed between the first transparent substrate 210 and the cholesteric liquid crystal layer 230, while the second photoalignment layer 242 is disposed between the second transparent substrate 220 and the cholesteric liquid crystal layer 230.

[0055] The first transparent substrate 210 includes a first transparent substrate 211 and a first transparent electrode layer 212. The first transparent electrode layer 212 is disposed between the first transparent substrate 211 and the first photoalignment layer 241. The second transparent substrate 220 may include a second transparent substrate 221 and a second transparent electrode layer 222. The second transparent electrode layer 222 is disposed between the second transparent substrate 221 and the second photoalignment layer 242. In the first embodiment, the materials of the first transparent substrate 211 and the second transparent substrate 221 are the same as the material of the first transparent substrate 111, and the materials of the first transparent electrode layer 212 and the second transparent electrode layer 222 are the same as the material of the first transparent electrode layer 112.

[0056] In some embodiments, an adhesive layer 101 may be provided between adjacent stacked cholesteric liquid crystal modules 100 and 200. The adhesive layer 101 may be composed of optical clear adhesive (OCA). Since the thickness of the adhesive layer 101 is only between tens and hundreds of micrometers, it is negligible, thus allowing the cholesteric liquid crystal modules 100 and 200 to fit tightly together. Additionally, a light-absorbing layer 300 is configured to absorb light passing through the cholesteric liquid crystal modules 100 and 200, thereby improving the contrast of the image displayed in the cholesteric liquid crystal display device 10. The light-absorbing layer 300 may be, but is not limited to, a black photoresist material, a black thin film, or other suitable light-absorbing film layer.

[0057] In some embodiments, the rotation pitch of the liquid crystal molecules within each of the cholesteric liquid crystal modules 100 and 200 may be different. As mentioned earlier, the internal structures of the cholesteric liquid crystal modules 100 and 200 are identical, but the difference lies in the different rotation pitches of the cholesteric liquid crystal molecules within the cholesteric liquid crystal layers 130 and 230 of the modules. The rotation pitch of the liquid crystal molecules is closely related to the wavelength of the reflected light. In essence, if the rotation pitch of the liquid crystal molecules is the same as the wavelength of a certain color of light, then when the cholesteric liquid crystal is energized and rotates, it can reflect light of that color. In other words, the cholesteric liquid crystal modules 100 and 200 can reflect different colors of light. In other embodiments, the cholesteric liquid crystal display device may include three stacked cholesteric liquid crystal modules, which respectively reflect red, green, and blue light. Thus, the cholesteric liquid crystal display device, after light mixing control, can serve as a full-color cholesteric liquid crystal display (ChLCD) with high contrast.

[0058] Please refer to the following: Figure 1 , Figure 2A and Figure 2B ,in Figure 2A It is a drawing Figure 1A schematic diagram of the alignment direction of the upper liquid crystal cell in a cholesterol liquid crystal display device. Figure 2B It is a drawing Figure 1 This is a schematic diagram of the alignment direction of the lower liquid crystal cell in a cholesteric liquid crystal display device. It should be noted that in the cholesteric liquid crystal display device 10, the first photoalignment layer 141 and the second photoalignment layer 142 in the upper liquid crystal cell, and the first photoalignment layer 241 and the second photoalignment layer 242 in the lower liquid crystal cell, can have different alignment directions after photo-alignment processing; that is, each photoalignment layer corresponds to a different photoalignment angle. The photoalignment process involves irradiating the photoalignment layer with alignment light (e.g., linearly polarized light) to provide an alignment direction to the cholesteric liquid crystal in the cholesteric liquid crystal layer. The direction of the alignment light determines the corresponding alignment direction of the photoalignment layer.

[0059] like Figure 2A As shown, the first photoalignment layer 141 in the upper liquid crystal cell provides a first alignment direction D1 (e.g., 90°) for each pixel of the cholesteric liquid crystal layer 130 along the solid arrow, while the second photoalignment layer 142 provides a second alignment direction D2 (e.g., 0°) for each pixel of the cholesteric liquid crystal layer 130 along the dashed arrow. Figure 2A The angle between the solid and dashed arrows in the diagram is used as a reference, and the first alignment direction D1 and the second alignment direction D2 differ by 90 degrees. For example... Figure 2B As shown, the first photoalignment layer 241 in the lower liquid crystal cell provides a first alignment direction D3 (e.g., 45°) for each pixel of the cholesteric liquid crystal layer 230 along the solid arrow, while the second photoalignment layer 242 provides a second alignment direction D4 (e.g., 315° or -45°) for each pixel of the cholesteric liquid crystal layer 230 along the dashed arrow. Figure 2B Based on the angle between the solid and dashed arrows, the first alignment direction D3 and the second alignment direction D4 differ by 90 degrees. Furthermore, the first alignment direction D1 of the upper liquid crystal cell and the first alignment direction D3 of the lower liquid crystal cell differ by 45 degrees, and the second alignment direction D2 of the upper liquid crystal cell and the second alignment direction D4 of the lower liquid crystal cell also differ by 45 degrees.

[0060] In some embodiments, the liquid crystal molecules in each of the adjacent stacked cholesteric liquid crystal modules 100 and 200 may have the same rotation pitch, while the optical rotation of the cholesteric liquid crystal modules 100 and 200 may be different. Specifically, one of the cholesteric liquid crystal modules 100 and 200 may have left-handed optical rotation, while the other may have right-handed optical rotation. Left-handed cholesteric liquid crystal molecules can only reflect left-handed circularly polarized light, while right-handed circularly polarized light will pass through. Conversely, right-handed cholesteric liquid crystal molecules can only reflect right-handed circularly polarized light, while left-handed circularly polarized light will pass through. Thus, the cholesteric liquid crystal display device 10 includes two cholesteric liquid crystal modules 100 and 200 with the same rotation pitch of liquid crystal molecules, and the upper and lower left-handed and right-handed liquid crystal cells are given different alignment directions and their photoalignment angles can be spaced at different angular periods, which not only improves reflectivity and contrast, but also compensates for the reflection intensity at different viewing angles, making the reflectivity closer to uniform.

[0061] Please refer to the following: Figure 1 , Figure 2A , Figure 2B and Figure 3 ,in Figure 3 This is a schematic diagram illustrating the alignment direction of the first photoalignment layer of the upper liquid crystal cell in a second embodiment of a cholesterol liquid crystal display device according to the first embodiment of this disclosure. It should be noted that... Figure 3 The internal structure configuration of the cholesterol liquid crystal display device 10a is the same as that of the other two. Figure 1 The cholesterol liquid crystal display device 10 differs from the previous one in that the first photoalignment layer 141a in the upper liquid crystal cell of the cholesterol liquid crystal display device 10a may include multiple alignment units, each of which has multiple alignment directions. One of the multiple alignment directions may differ from another of the multiple alignment directions by 45 degrees.

[0062] Specifically, the plurality of alignment units can be divided into a plurality of first alignment units U1 and a plurality of second alignment units U2. The plurality of first alignment units U1 and the plurality of second alignment units U2 are arranged alternately to form a grid pattern. Each of the first alignment units U1 may have a first alignment direction, which is equivalent to... Figure 2A The first alignment direction D1. Each of the second alignment elements U2 may have a second alignment direction, which is equivalent to the first alignment direction D1. Figure 2B The first alignment direction D3 in the first alignment unit U1 is 45 degrees different from the second alignment direction (e.g., 45°) of the second alignment unit U2.

[0063] In some embodiments, each of the second photoalignment layer in the upper liquid crystal cell and the first and second photoalignment layers in the lower liquid crystal cell of the cholesteric liquid crystal display device 10a may also include a plurality of first alignment units (not shown) and a plurality of second alignment units (not shown). Please refer to Table 1, which provides examples of the alignment directions of the first and second photoalignment layers in the upper and lower liquid crystal cells of the cholesteric liquid crystal display device 10a, but the present disclosure is not limited thereto.

[0064]

[0065] As shown in Table 1, the first alignment unit of the second photoalignment layer in the upper liquid crystal cell can have the same characteristics as... Figure 2A The second alignment direction D2 (e.g., 0°) in the upper liquid crystal cell. The second alignment unit of the second photoalignment layer in the upper liquid crystal cell may have an equivalent to Figure 2B The second alignment direction D4 (e.g., -45°) is used. Therefore, in the second photoalignment layer of the upper liquid crystal cell, the first alignment direction (e.g., 0°) of the first alignment unit differs from the second alignment direction (e.g., -45°) of the first alignment unit by 45 degrees. The other photoalignment layers follow the same principle and will not be described in detail.

[0066] In the second embodiment, the cholesteric liquid crystal display device 10a employs mask blocking and photoalignment technology to precisely control the first alignment direction and second alignment direction of the first alignment unit U1 and the second alignment unit U2 of the first photoalignment layer 141a to the cholesteric liquid crystal layer, and so on for the remaining photoalignment layers. This allows the cholesteric liquid crystal display device 10a to perform photoalignment on a single pixel or multiple pixel basis. For each alignment unit (i.e., the first alignment unit U1 or the second alignment unit U2), by changing the pattern design of the mask, adjacent alignment units can have different alignment directions, thereby effectively reducing the variation of reflectivity at different viewing angles and improving the viewing angle uniformity of the cholesteric liquid crystal display device 10a.

[0067] Furthermore, the first photoalignment layer 141a in the upper liquid crystal cell of the cholesteric liquid crystal display device 10a may also include an unaligned unit UN, which has a grid-like structure. Specifically, the unaligned unit UN is located in the gap region between the electrodes in the first transparent electrode layer 112, and the unaligned unit UN represents the area on the first photoalignment layer 141a that has not undergone photoalignment processing. In this way, the cholesteric liquid crystal molecules aligned with the unaligned unit UN are not directly interfered with by the electric field in the switching state. The scattered arrangement of the cholesteric liquid crystal molecules makes them appear darker, allowing the cholesteric liquid crystal molecules aligned with the unaligned unit UN to maintain their original state during display, without changing their alignment direction with changes in the electric field. This provides more stable optical properties and significantly improves the contrast of the displayed image.

[0068] Please refer to the following: Figure 1 , Figure 4 and Figure 5 ,in Figure 4 This is a schematic diagram illustrating the alignment direction of the first photoalignment layer of the upper liquid crystal cell in a third embodiment of a cholesterol liquid crystal display device according to the first embodiment of this disclosure. Figure 5 This is a schematic diagram illustrating the alignment direction of the first photoalignment layer of the upper liquid crystal cell in a fourth embodiment of a cholesterol liquid crystal display device according to the first embodiment of this disclosure. It should be noted that... Figure 4 and Figure 5 The internal structure configurations of the cholesterol liquid crystal display devices 10b and 10c are the same as those in the above-mentioned devices. Figure 1 The cholesterol liquid crystal display device 10 in the middle.

[0069] like Figure 4 and Figure 5 As shown, in the first photoalignment layers 141b and 141c of the cholesteric liquid crystal display devices 10b and 10c, a plurality of first alignment units U1 and a plurality of second alignment units U2 are arranged alternately to form a striped pattern. The difference between the cholesteric liquid crystal display device 10b and the cholesteric liquid crystal display device 10c is that the striped pattern of the cholesteric liquid crystal display device 10b is a stripe extending along the longitudinal direction, while the striped pattern of the cholesteric liquid crystal display device 10c is a stripe extending along the transverse direction. However, this disclosure is not limited to the number of first alignment units U1 and second alignment units U2.

[0070] Please refer to the following: Figure 1 , Figure 2A , Figure 2B and Figure 6 ,in Figure 6 This is a schematic diagram illustrating the alignment direction of the first photoalignment layer of the upper liquid crystal cell in the fifth embodiment of the cholesterol liquid crystal display device according to the first embodiment of this disclosure. It should be noted that... Figure 6 The internal structure configuration of the cholesterol liquid crystal display device 10d is the same as that of Figure 1 The difference between the cholesteric liquid crystal display device 10 and the cholesteric liquid crystal display device 10d is that the first photoalignment layer 141d in the upper liquid crystal cell of the cholesteric liquid crystal display device 10d may include a plurality of first alignment units U1, a plurality of second alignment units U2, a plurality of third alignment units U3, and a plurality of fourth alignment units U4. One of the plurality of first alignment units U1, one of the plurality of second alignment units U2, one of the plurality of third alignment units U3, and one of the plurality of fourth alignment units U4 are arranged sequentially at intervals to form a grid pattern.

[0071] In detail, each of the first alignment units U1 has a first alignment direction, and it is equivalent to... Figure 2A The first alignment direction D1. Each of the second alignment elements U2 may have a second alignment direction, which is equivalent to the first alignment direction D1. Figure 2B The first alignment direction D3. Each of the third alignment elements U3 may have a third alignment direction, and it is equivalent to the first alignment direction D3. Figure 2A The second alignment direction D2 in the second alignment direction. Each of the fourth alignment elements U4 may have a fourth alignment direction, and it is equivalent to the fourth alignment direction. Figure 2B The second alignment direction is D4. Therefore, the first alignment direction of the first alignment unit U1 (e.g., 90°), the second alignment direction of the second alignment unit U2 (e.g., 45°), the third alignment direction of the third alignment unit U3 (e.g., 0°), and the fourth alignment direction of the fourth alignment unit U4 (e.g., -45°) are sequentially 45 degrees apart.

[0072] In some embodiments, each of the second photoalignment layer in the upper liquid crystal cell and the first and second photoalignment layers in the lower liquid crystal cell of the cholesteric liquid crystal display device 10d may also include a plurality of first alignment units (not shown), a plurality of second alignment units (not shown), a plurality of third alignment units (not shown), and a plurality of fourth alignment units (not shown). Please refer to Table 2, which provides examples of the alignment directions of the first and second photoalignment layers in the upper and lower liquid crystal cells of the cholesteric liquid crystal display device 10d, but the present disclosure is not limited thereto.

[0073]

[0074] As shown in Table 2, within the same liquid crystal cell, the alignment directions of the first and second photoalignment layers can differ by 90°. Furthermore, within the same liquid crystal cell and the same photoalignment layer, the alignment directions of different alignment units can sequentially differ by 45°. Because the alignment directions of each alignment unit in each photoalignment layer are different, the cholesteric liquid crystal display device 10d can more effectively reduce the variation in reflectivity at different viewing angles compared to cholesteric liquid crystal display devices 10, 10a, 10b, and 10c, thereby improving the viewing angle uniformity of the cholesteric liquid crystal display device 10d. In other embodiments, the positions of the first to fourth alignment units can be randomly distributed to avoid overly periodic arrangements that are easily discernible to the human eye or form a moiré pattern effect.

[0075] Please refer to the following: Figure 1 , Figure 2A , Figure 2B and Figure 7 ,in Figure 7 This is a flowchart illustrating a method for manufacturing a cholesterol liquid crystal display device according to a second embodiment of the present disclosure. Figure 7As shown, the manufacturing method 20 for a cholesterol liquid crystal display device includes steps S01, S02, S03, and S04, and can be used to manufacture cholesterol liquid crystal display devices 10, 10a, 10b, 10c, and 10d. The following will take the manufacture of a cholesterol liquid crystal display device 10 having dual liquid crystal cells (i.e., having cholesterol liquid crystal modules 100 and 200 stacked together) as an example.

[0076] Step S01 involves forming at least one photoalignment layer on at least one of the first transparent substrate 110 and the second transparent substrate 120. In this embodiment, step S01 may include forming a first photoalignment layer 141 and a second photoalignment layer 142 on the first transparent substrate 110 and the second transparent substrate 120, respectively. Before forming the first photoalignment layer 141 and the second photoalignment layer 142, step S01 may further include providing a first transparent substrate 111 and forming a first transparent electrode layer 112 on the first transparent substrate 111, and providing a second transparent substrate 121 and forming a second transparent electrode layer 122 on the second transparent substrate 121. Furthermore, in step S01, the process for forming each electrode layer and each photoalignment layer may be a coating process, a deposition process, or other suitable processes. The deposition process may include, for example, atomic layer deposition (ALD), physical vapor deposition (PVD), chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), or other suitable deposition processes.

[0077] Step S02 involves irradiating at least one photoalignment layer with an alignment light source for exposure. In this embodiment, step S02 may include irradiating the first photoalignment layer 141 and the second photoalignment layer 142 with alignment light for exposure, such that after exposure, the first photoalignment layer 141 and the second photoalignment layer 142 respectively possess… Figure 2A The first alignment direction D1 and the second alignment direction D2 in the middle.

[0078] Step S03 involves assembling the first transparent substrate 110 and the second transparent substrate 120, and injecting liquid crystal molecules between the first transparent substrate 110 and the second transparent substrate 120 to form the cholesteric liquid crystal layer 130 in the cholesteric liquid crystal module 100. Thus, the cholesteric liquid crystal module 100 can be fabricated via steps S01 to S03, and the cholesteric liquid crystal module 200 is fabricated similarly. Furthermore, the first photoalignment layer 241 and the second photoalignment layer 242 in the cholesteric liquid crystal module 200 can respectively possess [specific properties] after exposure. Figure 2BThe first alignment direction D3 and the second alignment direction D4 are respectively provided in the cholesteric liquid crystal module 100. Therefore, the first photoalignment layer 141 and the second photoalignment layer 142 of the cholesteric liquid crystal module 100 can provide the first alignment direction D1 and the second alignment direction D2 for each pixel of the cholesteric liquid crystal layer 130. Similarly, the first photoalignment layer 241 and the second photoalignment layer 242 of the cholesteric liquid crystal module 200 can provide the first alignment direction D3 and the second alignment direction D4 for each pixel of the cholesteric liquid crystal layer 230.

[0079] Step S04 involves stacking multiple cholesterol liquid crystal modules 100 and 200, and setting a light absorption layer 300 at the bottom of the multiple cholesterol liquid crystal modules 100 and 200 to form a cholesterol liquid crystal display device 10.

[0080] In some embodiments, before performing step S02, the method 20 for manufacturing a cholesteric liquid crystal display device may further include covering the at least one photoalignment layer with a patterned mask to selectively block alignment light, so that the at least one photoalignment layer is divided into multiple alignment units after exposure, and the multiple alignment units may have different alignment directions. Specifically, taking the manufacturing of a cholesteric liquid crystal display device 10a as an example, before performing step S02, a designed patterned mask may be first covered on the first photoalignment layer 141a. The patterned mask is mainly used to selectively block alignment light, so that only the unblocked areas in the first photoalignment layer 141a can be exposed, thereby dividing the first photoalignment layer 141a into multiple first alignment units U1 and multiple second alignment units U2 (e.g., ...). Figure 3 As shown in the figure, the remaining photoalignment layers follow the same principle and will not be described in detail again. Therefore, the manufacturing method 20 of the cholesterol liquid crystal display device of this disclosure can employ masking technology to achieve multiple alignment directions as shown in Tables 1 and 2 above. By changing the pattern design of the mask, alignment can be performed on a unit of single pixel or multiple pixels, so that adjacent alignment units have different alignment directions, thereby effectively reducing the variation of reflectivity at different viewing angles and improving viewing angle uniformity.

[0081] In summary, the cholesteric liquid crystal display device and its manufacturing method disclosed herein have the following advantages: First, they can effectively reduce the variation of reflectivity at different viewing angles to improve viewing angle uniformity and overall reflectivity, and also expand the potential of cholesteric liquid crystal display devices in high-resolution and wide-viewing-angle display applications. Second, by configuring unaligned units in an arbitrary photoalignment layer, the cholesteric liquid crystal molecules aligned with the unaligned units can maintain their original state during the display process, without changing their alignment orientation with changes in the electric field, thereby providing more stable optical properties and significantly improving the contrast of the displayed image. Third, alignment units with different alignment orientations can be flexibly configured in the photoalignment layer, thereby avoiding overly periodic arrangement that could lead to moiré patterns.

[0082] Although the present disclosure has been described above with reference to embodiments, it is not intended to limit the present disclosure. Any person skilled in the art may make various changes and modifications without departing from the concept and scope of the present disclosure. Therefore, the scope of protection of the present disclosure shall be determined by the claims.

Claims

1. A cholesterol liquid crystal display device, characterized in that, Include: Multiple cholesterol liquid crystal modules are stacked on top of each other, wherein each of the multiple cholesterol liquid crystal modules comprises: A cholesterol liquid crystal layer containing multiple pixels; and At least one photoalignment layer is disposed on the cholesterol liquid crystal layer; and A light-absorbing layer is disposed at the bottom of the plurality of cholesterol liquid crystal modules; In this embodiment, at least one photoalignment layer of one of the plurality of cholesteric liquid crystal modules selectively provides an alignment direction for at least one of the plurality of pixels of that plurality of cholesteric liquid crystal modules based on a photoalignment process, and at least one photoalignment layer of another of the plurality of cholesteric liquid crystal modules selectively provides another alignment direction for at least one of the plurality of pixels of that other of the plurality of cholesteric liquid crystal modules based on the photoalignment process.

2. The cholesterol liquid crystal display device as described in claim 1, characterized in that, The number of at least two photoalignment layers is two, namely a first photoalignment layer and a second photoalignment layer, and the cholesteric liquid crystal layer is disposed between the first photoalignment layer and the second photoalignment layer; and Each of the plurality of cholesteric liquid crystal modules further includes a first transparent substrate and a second transparent substrate, wherein the first photoalignment layer is disposed on the first transparent substrate and the second photoalignment layer is disposed on the second transparent substrate.

3. The cholesterol liquid crystal display device as described in claim 2, characterized in that, The first photoalignment layer provides a first alignment direction for at least one of the plurality of pixels, and the second photoalignment layer provides a second alignment direction for at least one of the plurality of pixels, wherein the first alignment direction and the second alignment direction differ by 90 degrees.

4. The cholesterol liquid crystal display device as described in claim 1, characterized in that, This alignment direction is different from the other alignment direction.

5. The cholesterol liquid crystal display device as described in claim 1, characterized in that, An adhesive layer is provided between adjacent stacked cholesterol liquid crystal modules.

6. The cholesterol liquid crystal display device as claimed in claim 1, characterized in that, The rotational pitch of the liquid crystal molecules in each of the plurality of cholesterol liquid crystal modules is different.

7. The cholesterol liquid crystal display device as claimed in claim 1, characterized in that, The liquid crystal molecules in each of the plurality of cholesterol liquid crystal modules have the same rotational pitch.

8. The cholesterol liquid crystal display device as claimed in claim 1, characterized in that, The optical rotation of adjacent stacked cholesterol liquid crystal modules is different from that of each other.

9. The cholesterol liquid crystal display device as claimed in claim 1, characterized in that, The at least one photoalignment layer of the plurality of cholesterol liquid crystal modules includes a plurality of alignment units, each of the plurality of alignment units having a plurality of alignment directions, one of the plurality of alignment directions being 45 degrees away from another of the plurality of alignment directions.

10. The cholesterol liquid crystal display device as claimed in claim 9, characterized in that, The multiple alignment units are arranged alternately to form a grid pattern or a stripe pattern.

11. The cholesterol liquid crystal display device as claimed in claim 9, characterized in that, The at least one optical alignment layer also includes an unaligned unit, which has a grid-like structure.

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