Reflective display device and driving method

Abstract

The invention discloses a reflective display device and a driving method. The reflective display device comprises a first liquid crystal box and a second liquid crystal box stacked on the light emitting side of the first liquid crystal box. Second cholesteric liquid crystal molecules of the second liquid crystal box reflect first color light in a reflection state, first cholesteric liquid crystal molecules of the first liquid crystal box reflect complementary color light of the first color light in the reflection state, and a second color resistance layer and a third color resistance layer are arranged on the reflective display device. The projection of the second color resistance layer and the projection of the third color resistance layer on the reflective display device are completely staggered, at least one of the second color resistance layer and the third color resistance layer is arranged on the first opposite substrate, and the filtering wavelength of the second color resistance layer and the filtering wavelength of the third color resistance layer are partially overlapped with the wavelength of the complementary color light. Therefore, the reflective display device can realize color display by adopting the double liquid crystal boxes, the colors are richer, the box thickness is smaller, the display of three primary colors can be realized by only needing two sub-pixels, and the aperture opening ratio is larger.

Description

Technical Field

[0001] This invention relates to the field of display technology, and in particular to a reflective display device and its driving method. Background Technology

[0002] Display panels offer advantages such as thinness, durability, and low power consumption, which are energy-efficient and environmentally friendly. However, they require a backlight, resulting in a thicker module and higher cost. Electronic paper displays (reflective displays) have emerged as a solution to meet the needs of the general public. Unlike LCD displays, which require a backlight, electronic paper displays can use external light sources to display images. Therefore, even in strong sunlight, the information on the electronic paper remains clearly visible without viewing angle issues. Furthermore, due to their energy efficiency, high reflectivity, and high contrast ratio, electronic paper displays are now widely used in e-readers (such as e-books and e-newspapers) and other electronic components (such as price tags).

[0003] Existing electronic paper displays typically employ E-Ink microcapsule technology (microcapsule electronic ink technology), SiPix microcup technology (microcup electrophoretic display technology), Bridgestone electronic liquid powder technology, cholesteric liquid crystal display (CLCD) technology, microelectromechanical systems (MEMS) technology, or electrowetting technology. However, existing electronic paper display technologies are less mature than liquid crystal display technologies, have lower mass production efficiency, higher manufacturing costs, and cannot achieve color display.

[0004] Existing reflective display devices using cholesteric liquid crystals (CLCs) suffer from limitations due to the pitch requirements of CLCs. A single-pitch CLC can only reflect one color while transmitting other colors. Therefore, single-layer CLC reflective display devices typically display text in yellow on a black background, black on a yellow background, black on a red background, or red on a black background, unable to achieve white text on a black background or black text on a white background like in a book. This significantly limits their application. Furthermore, the color quality of the reflected light from CLCs is poor, affecting the display effect. To achieve white or color display, reflective display devices require three layers of CLC cells, reflecting red, green, and blue light respectively. However, three-layer CLC cells are not only thicker but also require a thin-film transistor array substrate for each layer, increasing costs. Summary of the Invention

[0005] In order to overcome the shortcomings and deficiencies of the existing technology, the purpose of this invention is to provide a reflective display device and driving method to solve the problem that the existing technology requires a three-layer cholesteric liquid crystal cell to achieve full-color reflective display.

[0006] The objective of this invention is achieved through the following technical solution: The present invention provides a reflective display device, including a first liquid crystal cell and a second liquid crystal cell stacked on the light-emitting side of the first liquid crystal cell. The first liquid crystal cell has a plurality of first pixel units arranged in an array, and the second liquid crystal cell has a plurality of second pixel units arranged in an array. Each second pixel unit corresponds to at least one first pixel unit. The first liquid crystal cell includes a first opposing substrate, a first array substrate disposed opposite to the first opposing substrate, and a first cholesteric liquid crystal layer located between the first opposing substrate and the first array substrate. The first opposing substrate is located on the side of the first liquid crystal cell facing the second liquid crystal cell. The first cholesteric liquid crystal layer includes first cholesteric liquid crystal molecules. The first cholesteric liquid crystal molecules reflect light of the same color in the reflective state. The first array substrate is provided with a first pixel electrode corresponding to the first pixel unit. The first opposing substrate is provided with a first common electrode that cooperates with the first pixel electrode. The second liquid crystal cell includes a second opposing substrate, a second array substrate disposed opposite to the second opposing substrate, and a second cholesteric liquid crystal layer located between the second opposing substrate and the second array substrate. The second cholesteric liquid crystal layer includes second cholesteric liquid crystal molecules, all of which reflect light of the same color in the reflective state. The second array substrate is provided with a second pixel electrode corresponding to the second pixel unit, and the second opposing substrate is provided with a second common electrode that cooperates with the second pixel electrode. The second cholesteric liquid crystal molecule reflects the first color light in the reflective state, and the first cholesteric liquid crystal molecule reflects the complementary color light of the first color light in the reflective state. The reflective display device is provided with a second color resist layer and a third color resist layer. The projections of the second color resist layer and the third color resist layer on the reflective display device are completely staggered, and at least one of them is provided on the first opposing substrate. The filtering wavelengths of the second color resist layer and the third color resist layer partially overlap with the wavelength of the complementary color light.

[0007] Furthermore, each second pixel unit corresponds to two first pixel units of different colors. The second color resist layer and the third color resist layer are both disposed on the first opposing substrate and each corresponds to a different first pixel unit. The second opposing substrate is transparent in the area corresponding to the second pixel unit.

[0008] Furthermore, the first pixel unit and the second pixel unit correspond one-to-one, and the second opposing substrate is located on the side of the second liquid crystal cell away from the first liquid crystal cell; the third color resist layer is disposed on the first opposing substrate, the second color resist layer is disposed on the second opposing substrate, the first opposing substrate is transparent in the area corresponding to the second color resist layer, and the second opposing substrate is transparent in the area corresponding to the third color resist layer.

[0009] Furthermore, the first pixel unit and the second pixel unit correspond one-to-one, and the second opposing substrate is located on the side of the second liquid crystal cell away from the first liquid crystal cell; the second color resist layer is disposed on the first opposing substrate, the third color resist layer is disposed on the second opposing substrate, the first opposing substrate is transparent in the area corresponding to the third color resist layer, and the second opposing substrate is transparent in the area corresponding to the second color resist layer.

[0010] Furthermore, the first color is blue, and one of the second and third colors is red, while the other is green; Alternatively, the first color is red, and one of the second and third colors is blue, while the other is green; Alternatively, the first color is green, and one of the second and third colors is red, while the other is blue.

[0011] Furthermore, the reflective display device includes a light-absorbing layer disposed over its entire surface. The light-absorbing layer is located on the side of the first liquid crystal cell away from the second liquid crystal cell and is used to absorb light passing through the first liquid crystal cell and the second liquid crystal cell.

[0012] Furthermore, a first black matrix is ​​provided on the first opposing substrate, which is used to separate the plurality of first pixel units from each other. The second opposing substrate is provided with a second black matrix, which is used to separate multiple second pixel units from each other.

[0013] This application also provides a driving method for a reflective display device, used to drive the reflective display device as described above, the driving method comprising: When displaying the first color, the second cholesteric liquid crystal molecules in the corresponding area of ​​the second pixel unit are controlled to be in a reflective state and the first cholesteric liquid crystal molecules in the corresponding area are in a transparent or hazy state. At this time, the second pixel unit reflects the first color light. When displaying the second color, the second cholesteric liquid crystal molecules in the region corresponding to the second pixel unit are controlled to be in a transparent or hazy state, the first cholesteric liquid crystal molecules in the region corresponding to the second color resist layer are controlled to be in a reflective state, and the first cholesteric liquid crystal molecules in the region corresponding to the third color resist layer are controlled to be in a transparent or hazy state. At this time, the first pixel unit in the region corresponding to the second color resist layer reflects the second color light. When displaying the third color, the second cholesteric liquid crystal molecules in the region corresponding to the second pixel unit are controlled to be in a transparent or hazy state, the first cholesteric liquid crystal molecules in the region corresponding to the third color resist layer are controlled to be in a reflective state, and the first cholesteric liquid crystal molecules in the region corresponding to the second color resist layer are controlled to be in a transparent or hazy state. At this time, the first pixel unit in the region corresponding to the third color resist layer reflects the third color light. In the dark state, the second cholesteric liquid crystal molecules in the region corresponding to the second pixel unit are controlled to be either transparent or hazy, and the first cholesteric liquid crystal molecules in the region corresponding to the first pixel unit are controlled to be either transparent or hazy. At this time, light passes directly through the first cholesteric liquid crystal layer and the second cholesteric liquid crystal layer.

[0014] This application also provides a driving method for a reflective display device, used to drive the reflective display device as described above, the driving method comprising: When displaying the first color, the first cholesteric liquid crystal molecules and the second cholesteric liquid crystal molecules in the region corresponding to the second color resist layer are controlled to be in a transparent or hazy state, the second cholesteric liquid crystal molecules in the region corresponding to the third color resist layer are controlled to be in a reflective state, and the first cholesteric liquid crystal molecules in the region corresponding to the third color resist layer are controlled to be in a transparent or hazy state. At this time, the second pixel unit corresponding to the third color resist layer reflects the first color light. When displaying the second color, the second cholesteric liquid crystal molecules in the region corresponding to the second pixel unit are controlled to be in a transparent or hazy state, the first cholesteric liquid crystal molecules in the region corresponding to the second color resist layer are controlled to be in a reflective state, and the first cholesteric liquid crystal molecules in the region corresponding to the third color resist layer are controlled to be in a transparent or hazy state. At this time, the first pixel unit in the region corresponding to the second color resist layer reflects the second color light. When displaying the third color, the second cholesteric liquid crystal molecules in the region corresponding to the second pixel unit are controlled to be in a transparent or hazy state, the first cholesteric liquid crystal molecules in the region corresponding to the third color resist layer are controlled to be in a reflective state, and the first cholesteric liquid crystal molecules in the region corresponding to the second color resist layer are controlled to be in a transparent or hazy state. At this time, the first pixel unit in the region corresponding to the third color resist layer reflects the third color light. In the dark state, the second cholesteric liquid crystal molecules in the region corresponding to the second pixel unit are controlled to be either transparent or hazy, and the first cholesteric liquid crystal molecules in the region corresponding to the first pixel unit are controlled to be either transparent or hazy. At this time, light passes directly through the first cholesteric liquid crystal layer and the second cholesteric liquid crystal layer.

[0015] This application also provides a driving method for a reflective display device, used to drive the reflective display device as described above, the driving method comprising: When displaying the first color, the first cholesteric liquid crystal molecules and the second cholesteric liquid crystal molecules in the region corresponding to the third color resist layer are controlled to be in a transparent or hazy state, the second cholesteric liquid crystal molecules in the region corresponding to the second color resist layer are controlled to be in a reflective state, and the first cholesteric liquid crystal molecules in the region corresponding to the second color resist layer are controlled to be in a transparent or hazy state. At this time, the second pixel unit corresponding to the second color resist layer reflects the first color light. When displaying the second color, the second cholesteric liquid crystal molecules in the region corresponding to the second pixel unit are controlled to be in a transparent or hazy state, the first cholesteric liquid crystal molecules in the region corresponding to the second color resist layer are controlled to be in a reflective state, and the first cholesteric liquid crystal molecules in the region corresponding to the third color resist layer are controlled to be in a transparent or hazy state. At this time, the first pixel unit in the region corresponding to the second color resist layer reflects the second color light. When displaying the third color, the second cholesteric liquid crystal molecules in the region corresponding to the second pixel unit are controlled to be in a transparent or hazy state, the first cholesteric liquid crystal molecules in the region corresponding to the third color resist layer are controlled to be in a reflective state, and the first cholesteric liquid crystal molecules in the region corresponding to the second color resist layer are controlled to be in a transparent or hazy state. At this time, the first pixel unit in the region corresponding to the third color resist layer reflects the third color light. In the dark state, the second cholesteric liquid crystal molecules in the region corresponding to the second pixel unit are controlled to be either transparent or hazy, and the first cholesteric liquid crystal molecules in the region corresponding to the first pixel unit are controlled to be either transparent or hazy. At this time, light passes directly through the first cholesteric liquid crystal layer and the second cholesteric liquid crystal layer.

[0016] The beneficial effects of this invention are as follows: By setting a first liquid crystal cell and a second liquid crystal cell stacked on the light-emitting side of the first liquid crystal cell in the reflective display device, the second cholesteric liquid crystal molecules of the second liquid crystal cell reflect the first color light in the reflective state, and the first cholesteric liquid crystal molecules of the first liquid crystal cell reflect the complementary color light of the first color light in the reflective state. The projections of the second color resist layer and the third color resist layer on the reflective display device are completely staggered, and at least one of them is disposed on the first opposing substrate of the first liquid crystal cell. The filtering wavelengths of the second color resist layer and the third color resist layer partially overlap with the wavelengths of the complementary color light. Thus, the reflective display device can achieve full-color display with dual liquid crystal cells, resulting in richer colors, a smaller cell thickness, and the ability to display the three primary colors with only two sub-pixels. It also has a larger pixel aperture ratio, requires fewer IC channels, and is cheaper, thus featuring low cost and low power consumption. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the reflective display device in its initial state according to Embodiment 1 of the present invention.

[0018] Figure 2 This is a schematic diagram of the planar structure of the reflective display device in Embodiment 1 of the present invention.

[0019] Figure 3 This is a schematic diagram of the color resist arrangement structure of the first liquid crystal cell in Embodiment 1 of the present invention.

[0020] Figure 4 This is a schematic diagram of the planar structure of the first array substrate in Embodiment 1 of the present invention.

[0021] Figure 5 This is a schematic diagram of the planar structure of the second array substrate in Embodiment 1 of the present invention.

[0022] Figure 6 This is a schematic diagram illustrating the principle of the three state transformations of cholesteric liquid crystal in Embodiment 1 of the present invention.

[0023] Figure 7 This is a schematic diagram of the driving signals for the three state transitions of cholesteric liquid crystal in Embodiment 1 of the present invention.

[0024] Figure 8 This is a schematic diagram of the structure of the reflective display device in Embodiment 1 of the present invention when displaying a pure blue image.

[0025] Figure 9 This is a schematic diagram of the structure of the reflective display device in Embodiment 1 of the present invention when displaying a pure red image.

[0026] Figure 10 This is a schematic diagram of the structure of the reflective display device in Embodiment 1 of the present invention when displaying a pure green image.

[0027] Figure 11 This is a schematic diagram of the reflective display device in Embodiment 1 of the present invention when displaying a color image.

[0028] Figure 12 This is a schematic diagram of the structure of the reflective display device in Embodiment 1 of the present invention when displaying a pure black image.

[0029] Figure 13 This is one of the structural schematic diagrams of the reflective display device in its initial state in Embodiment 2 of the present invention.

[0030] Figure 14 This is the second schematic diagram of the reflective display device in its initial state in Embodiment 2 of the present invention.

[0031] Figure 15 This is a schematic diagram of the reflective display device in its initial state according to Embodiment 3 of the present invention.

[0032] Figure 16 This is a schematic diagram of the planar structure of the second array substrate in Embodiment 3 of the present invention.

[0033] Figure 17 This is a schematic diagram of the structure of the reflective display device in Embodiment 3 of the present invention when displaying a pure blue image.

[0034] Figure 18 This is a schematic diagram of the reflective display device in Embodiment 3 of the present invention when displaying a pure red image.

[0035] Figure 19 This is a schematic diagram of the reflective display device in Embodiment 3 of the present invention when displaying a pure green image.

[0036] Figure 20 This is a schematic diagram of the reflective display device in Embodiment 3 of the present invention when displaying a color image.

[0037] Figure 21 This is a schematic diagram of the reflective display device in Embodiment 3 of the present invention when displaying a pure black image.

[0038] Figure 22 This is a schematic diagram of the reflective display device in its initial state according to Embodiment 4 of the present invention. Detailed Implementation

[0039] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following detailed description, in conjunction with the accompanying drawings and preferred embodiments, provides a detailed explanation of the specific implementation methods, structures, features, and effects of the reflective display device and driving method proposed according to the present invention: [Example 1] Figure 1This is a schematic diagram of the reflective display device in its initial state according to Embodiment 1 of the present invention. Figure 2 This is a schematic diagram of the planar structure of the reflective display device in Embodiment 1 of the present invention. Figure 3 This is a schematic diagram of the color resist arrangement structure of the first liquid crystal cell in Embodiment 1 of the present invention. Figure 4 This is a schematic diagram of the planar structure of the first array substrate in Embodiment 1 of the present invention. Figure 5 This is a schematic diagram of the planar structure of the second array substrate in Embodiment 1 of the present invention.

[0040] like Figures 1 to 5 As shown, a reflective display device provided in Embodiment 1 of the present invention includes a first liquid crystal cell 10 and a second liquid crystal cell 20 stacked on the light-emitting side of the first liquid crystal cell 10, that is, the second liquid crystal cell 20 is closer to the external environment than the first liquid crystal cell 10. The first liquid crystal cell 10 has a plurality of first pixel units P1 arranged in an array, and the second liquid crystal cell 20 has a plurality of second pixel units P2 arranged in an array, each second pixel unit P2 corresponding to at least one first pixel unit P1. In this embodiment, each second pixel unit P2 corresponds to two first pixel units P1 of different colors, that is, the projection of the second pixel unit P2 onto the first liquid crystal cell 10 covers two first pixel units P1 of different colors.

[0041] The first liquid crystal cell 10 includes a first opposing substrate 11, a first array substrate 12 disposed opposite to the first opposing substrate 11, and a first cholesteric liquid crystal layer 13 located between the first opposing substrate 11 and the first array substrate 12. The first opposing substrate 11 is located on the side of the first liquid crystal cell 10 facing the second liquid crystal cell 20, and the first array substrate 12 is located on the side of the first liquid crystal cell 10 away from the second liquid crystal cell 20. The first cholesteric liquid crystal layer 13 includes first cholesteric liquid crystal molecules 131, all of which reflect light of the same color in the reflective state.

[0042] Furthermore, the first array substrate 12 is provided with a first pixel electrode 121, and each first pixel unit P1 is provided with a corresponding first pixel electrode 121. The first pixel electrode 121 corresponds one-to-one with the first pixel unit P1, and the first pixel electrode 121 is a block electrode corresponding to the first pixel unit P1. The first opposing substrate 11 is provided with a first common electrode 111 that cooperates with the first pixel electrode 121. The first common electrode 111 is a planar electrode that covers the entire surface of the first opposing substrate 11.

[0043] The second liquid crystal cell 20 includes a second opposing substrate 21, a second array substrate 22 disposed opposite to the second opposing substrate 21, and a second cholesteric liquid crystal layer 23 located between the second opposing substrate 21 and the second array substrate 22. The second opposing substrate 21 is located on the side of the second liquid crystal cell 20 away from the first liquid crystal cell 10, and the second array substrate 22 is located on the side of the second liquid crystal cell 20 closer to the first liquid crystal cell 10. Optionally, the second array substrate 22 can share a substrate with the first opposing substrate 11, that is, the second array substrate 22 can be reused as the first opposing substrate 11, thereby reducing the cell thickness. The second cholesteric liquid crystal layer 23 includes second cholesteric liquid crystal molecules 231, which all reflect light of the same color in the reflective state. Among them, the second cholesteric liquid crystal molecules 231 reflect light of the first color in the reflective state, and the first cholesteric liquid crystal molecules 131 reflect the complementary color light of the first color light in the reflective state.

[0044] Optionally, since the first liquid crystal cell 10 is located on the side of the second liquid crystal cell 20 that is far from the external environment, the reflected light from the first liquid crystal cell 10 is subject to more interference than the reflected light from the second liquid crystal cell 20. Therefore, the cell thickness of the first liquid crystal cell 10 is set to 1.5 to 2 times that of the second liquid crystal cell 20, for example, the cell thickness of the first liquid crystal cell 10 is 4 to 6 μm and the cell thickness of the second liquid crystal cell 20 is 8 to 10 μm, in order to improve the reflectivity of the second liquid crystal cell 20 and reduce the brightness difference between the first color light, the second color light and the third color light, thereby improving the display effect.

[0045] Furthermore, the reflective display device is provided with a color resist layer 113, which includes a second color resist layer 113a and a third color resist layer 113b. The projections of the second color resist layer 113a and the third color resist layer 113b on the reflective display device are completely staggered, and at least one of the second color resist layer 113a and the third color resist layer 113b is disposed on the first opposing substrate 11. The filtering wavelengths of the second color resist layer 113a and the third color resist layer 113b both partially overlap with the wavelengths of complementary color rays. In this embodiment, both the second color resist layer 113a and the third color resist layer 113b are disposed on the first opposing substrate 11, and each corresponds to a different first pixel unit P1. The area corresponding to the second pixel unit P2 on the second opposing substrate 21 is transparent. That is, each first pixel unit P1 corresponds to a color resist layer 113 of one color, and each second pixel unit P2 corresponds to a first pixel unit P1 of a second color and a first pixel unit P1 of a third color.

[0046] Furthermore, the second array substrate 22 is provided with a second pixel electrode 221, and each second pixel unit P2 is provided with a corresponding second pixel electrode 221. The second pixel electrode 221 corresponds one-to-one with the second pixel unit P2, and the second pixel electrode 221 is a block electrode corresponding to the second pixel unit P2, that is, the first pixel electrode 121 corresponds one-to-one with the second pixel electrode 221. The second opposing substrate 21 is provided with a second common electrode 211 that cooperates with the second pixel electrode 212. The second common electrode 211 is a planar electrode that covers the entire surface of the second opposing substrate 21.

[0047] The cholesteric liquid crystal molecules (first cholesteric liquid crystal molecule 131 and second cholesteric liquid crystal molecule 231) possess three stable textures: P-state (Planar, reflective state), FC-state (Focal Conic, hazy state), and H-state (transparent state). In the P-state, the cholesteric liquid crystal's reflection spectrum is in the visible spectrum, reflecting bright colored light; the specific reflected color can be set according to the pitch of the cholesteric liquid crystal. In the FC-state, the cholesteric liquid crystal no longer reflects the aforementioned colored light, and light can be scattered and transmitted through it. In the H-state, the cholesteric liquid crystal no longer reflects the aforementioned colored light, and light can pass directly through it without scattering. Under a certain electric field, these three states can interconvert.

[0048] Figure 6 This is a schematic diagram illustrating the principle of the three state transformations of cholesteric liquid crystal in Embodiment 1 of the present invention. Figure 7 This is a schematic diagram of the driving signals for the three state transitions of cholesteric liquid crystal in Embodiment 1 of the present invention. Combined with... Figure 1 , Figure 6 and Figure 7As shown, a common voltage signal Vcom is applied to the common electrode (first common electrode 111, second common electrode 211), and a first electrical signal V1 is continuously applied to the pixel electrode (first pixel electrode 121, second pixel electrode 221). There is a voltage difference (about 20V) between the common voltage signal Vcom and the first electrical signal V1. A strong vertical electric field is formed between the common electrode and the pixel electrode, and the cholesteric liquid crystal molecules rotate and remain in the H state (transparent state). A common voltage signal Vcom is applied to the common electrode (first common electrode 111, second common electrode 211), and a second electrical signal V2 is applied to the pixel electrode (first pixel electrode 121, second pixel electrode 221). There is a voltage difference (e.g., 20V) between the second electrical signal V2 and the common voltage signal Vcom, and the second electrical signal V2 gradually becomes the same as the common voltage signal Vcom within a first preset time. That is, the second electrical signal V2 first has a large voltage difference with the common voltage signal Vcom, and then slowly decreases and becomes the same as the common voltage signal Vcom. Therefore, a strong vertical electric field is first formed between the common electrode and the pixel electrode, and then the vertical electric field slowly disappears, causing the cholesteric liquid crystal molecules to rotate and stagnate in the FC state, which is a scattering state and has a light-scattering effect. A common voltage signal Vcom is applied to the common electrodes (first common electrode 111, second common electrode 211), and a third electrical signal V3 is applied to the pixel electrodes (first pixel electrode 121, second pixel electrode 221). There is a voltage difference (e.g., 30V) between the third electrical signal V3 and the common voltage signal Vcom. The third electrical signal V3 directly becomes the same as the common voltage signal Vcom at a second preset time. The second preset time is shorter than the first preset time; that is, the third electrical signal V3 initially has a large voltage difference with the common voltage signal Vcom, and then rapidly decreases to become the same as the common voltage signal Vcom. Therefore, a strong vertical electric field is initially formed between the common electrode and the pixel electrode, and then the vertical electric field rapidly disappears, causing the cholesteric liquid crystal molecules to rotate and stagnate in the P state, which is a reflective state. The different arrangement directions of the cholesteric liquid crystal molecules result in different reflected visible light spectra, while the remaining spectrum is transmitted. The P state and FC state do not require voltage to maintain. The reflection spectrum band (Δλ) of cholesteric liquid crystal molecules is proportional to the pitch (Po) and average refractive index (n=(ne+no) / 2) of the cholesteric liquid crystal molecules, and the formula is: Δλ=nPo. Therefore, cholesteric liquid crystal molecules with different pitches can reflect different colors of light in the reflective state.

[0049] like Figure 4As shown, a first array substrate 12 is provided with multiple first scan lines 101 and multiple first data lines 102. The multiple first scan lines 101 and multiple first data lines 102 are mutually insulated and intersecting to form multiple first pixel units P1. Each first pixel unit P1 is provided with a first thin-film transistor 103 and a first pixel electrode 121. The first pixel electrode 121 is electrically connected to the first scan line 101 and the first data line 102 adjacent to the first thin-film transistor 103 through the first thin-film transistor 103. The first thin-film transistor 103 includes a first gate, a first active layer, a first drain, and a first source. The first gate and the first scan line 101 are located on the same layer and are electrically connected. The first gate and the first active layer are isolated by an insulating layer. The first source is electrically connected to the first data line 102. The first drain is electrically connected to the first pixel electrode 121 through a contact hole.

[0050] like Figure 5 As shown, the second array substrate 22 is provided with multiple second scan lines 201 and multiple second data lines 202. The multiple second scan lines 201 and multiple second data lines 202 are mutually insulated and intersecting to form multiple second pixel units P2. The second array substrate 22 provides a second thin film transistor 203 and a second pixel electrode 221 in each second pixel unit P2. The second pixel electrode 221 is electrically connected to the second scan line 201 and the second data line 202 adjacent to the second thin film transistor 203 through the second thin film transistor 203. The second thin film transistor 203 includes a second gate, a second active layer, a second drain, and a second source. The second gate and the second scan line 201 are located on the same layer and are electrically connected. The second gate and the second active layer are isolated by an insulating layer. The second source is electrically connected to the second data line 202. The second drain is electrically connected to the second pixel electrode 221 through a contact hole.

[0051] Optionally, the projection of the second scan line 201 on the first array substrate 122 overlaps with the first scan line 101, the projection of the second data line 202 on the first array substrate 12 overlaps with the first data line 102, the projection of the second thin film transistor 203 on the first array substrate 12 overlaps with the first thin film transistor 103, and the projection of the second pixel electrode 221 on the first array substrate 12 covers the two first pixel electrodes 121.

[0052] In this embodiment, the first cholesteric liquid crystal molecule 131 reflects the fourth color light in its reflective state, and the second cholesteric liquid crystal molecule 231 reflects the first color light in its reflective state. The first and fourth colors are complementary colors, meaning that the first and fourth colors mix to produce white. The first, second, and third colors are each one of red, green, and blue. In this embodiment, the first color is blue, and one of the second and third colors is red, while the other is green. For example, the first cholesteric liquid crystal molecule 131 is a yellow cholesteric liquid crystal molecule, the second cholesteric liquid crystal molecule 231 is a blue cholesteric liquid crystal molecule, the second dye liquid crystal molecule 232 is a blue dye liquid crystal molecule, the second color resist layer 113a is a red color resist, and the third color resist layer 113b is a green color resist. Alternatively, in other embodiments, the first cholesteric liquid crystal molecule 131 is a yellow cholesteric liquid crystal molecule, the second cholesteric liquid crystal molecule 231 is a blue cholesteric liquid crystal molecule, the second dye liquid crystal molecule 232 is a blue dye liquid crystal molecule, the second color resist layer 113a is a green color resist, and the third color resist layer 113b is a red color resist.

[0053] Furthermore, the reflective display device includes a light-absorbing layer 30 disposed across its entire surface. The light-absorbing layer 30 is located on the side of the first liquid crystal cell 10 away from the second liquid crystal cell 20 and is used to absorb light passing through the first liquid crystal cell 10 and the second liquid crystal cell 20, thereby making the reflective display device appear darker in black, thus improving contrast. Optionally, the light-absorbing layer 30 uses black ink with an L value (representing brightness) greater than 25 and an OD value (optical density) greater than 4, thus giving the light-absorbing layer 30 high blackness and good gloss, ensuring a deeper black image. Of course, the light-absorbing layer 30 can be made of BM material. In this embodiment, the light-absorbing layer 30 is a planar structure covering the entire surface of the first array substrate 12, and the light-absorbing layer 30 covers the side of the first array substrate 12 away from the first cholesteric liquid crystal layer 13.

[0054] Furthermore, the first opposing substrate 11 is provided with a first black matrix 112, which is used to space out multiple first pixel units P1 from each other; the second opposing substrate 21 is provided with a second black matrix 212, which is used to space out multiple second pixel units P2 from each other. The size of the holes in the second black matrix 212 is twice the size of the holes in the first black matrix 112.

[0055] The first opposing substrate 11, the first array substrate 12, the second opposing substrate 21, and the second array substrate 22 can be made of transparent substrates such as glass, acrylic, and polycarbonate. The first common electrode 111, the first pixel electrode 121, the second common electrode 211, and the second pixel electrode 221 can all be made of transparent electrodes such as indium tin oxide (ITO) or indium zinc oxide (IZO).

[0056] This application also provides a driving method for a reflective display device, used to drive the reflective display device as described above. The driving method includes: When displaying the first color, the second cholesteric liquid crystal molecule 231 in the corresponding area of ​​the second pixel unit P2 is controlled to be in a reflective state and the first cholesteric liquid crystal molecule 131 in the corresponding area is in a transparent state or a hazy state. At this time, the second pixel unit P2 reflects the first color light. Figure 8 This is a schematic diagram of the reflective display device in Embodiment 1 of the present invention when displaying a pure blue image. Figure 8 As shown, when displaying the first color (blue), the second cholesteric liquid crystal molecule 231 in the area corresponding to the second pixel unit P2 is controlled to lie flat, so that the second cholesteric liquid crystal molecule 231 in the area corresponding to the second pixel unit P2 is in a reflective state. The first cholesteric liquid crystal molecule 131 in the area corresponding to the second pixel unit P2 is controlled to stand vertically or be in a disordered tilted state, so that the first cholesteric liquid crystal molecule 131 in the area corresponding to the second pixel unit P2 is in a transparent state or a foggy state. At this time, the second pixel unit P2 reflects the first color light (blue light) through the second cholesteric liquid crystal molecule 231.

[0057] When displaying the second color, the second cholesteric liquid crystal molecule 231 in the region corresponding to the second pixel unit P2 is controlled to be in a transparent or hazy state, the first cholesteric liquid crystal molecule 131 in the region corresponding to the second color resist layer 113a is controlled to be in a reflective state, and the first cholesteric liquid crystal molecule 131 in the region corresponding to the third color resist layer 113b is controlled to be in a transparent or hazy state. At this time, the first pixel unit P1 in the region corresponding to the second color resist layer 113a reflects the second color light. Figure 9 This is a schematic diagram of the reflective display device in Embodiment 1 of the present invention when displaying a pure red image. Figure 9 As shown, when displaying the second color (red), the second cholesteric liquid crystal molecules 231 in the region corresponding to the second pixel unit P2 are controlled to stand vertically or be in a disordered tilted state, so that the second cholesteric liquid crystal molecules 231 in the region corresponding to the second pixel unit P2 are in a transparent state or a hazy state; the first cholesteric liquid crystal molecules 131 in the region corresponding to the second color resist layer 113a are controlled to lie flat, so that the first cholesteric liquid crystal molecules 131 in the region corresponding to the second color resist layer 113a are in a reflective state; and the first cholesteric liquid crystal molecules 131 in the region corresponding to the third color resist layer 113b are controlled to stand vertically or be in a disordered tilted state, so that the first cholesteric liquid crystal molecules 131 in the region corresponding to the third color resist layer 113b are in a transparent state or a hazy state; at this time, the first pixel unit P1 in the region corresponding to the second color resist layer 113a reflects the second color light (red light) through the first cholesteric liquid crystal molecules 131 and is emitted from the second color resist layer 113a.

[0058] When displaying the third color, the second cholesteric liquid crystal molecule 231 in the region corresponding to the second pixel unit P2 is controlled to be in a transparent or hazy state, the first cholesteric liquid crystal molecule 131 in the region corresponding to the third color resist layer 113b is controlled to be in a reflective state, and the first cholesteric liquid crystal molecule 131 in the region corresponding to the second color resist layer 113a is controlled to be in a transparent or hazy state. At this time, the first pixel unit P1 in the region corresponding to the third color resist layer 113b reflects the third color light. Figure 10 This is a schematic diagram of the reflective display device in Embodiment 1 of the present invention when displaying a pure green image. Figure 10 As shown, when displaying the third color (green), the second cholesteric liquid crystal molecules 231 in the region corresponding to the second pixel unit P2 are controlled to stand vertically or be in a disordered tilted state, so that the second cholesteric liquid crystal molecules 231 in the region corresponding to the second pixel unit P2 are in a transparent state or a foggy state; the first cholesteric liquid crystal molecules 131 in the region corresponding to the third color resist layer 113b are controlled to lie flat, so that the first cholesteric liquid crystal molecules 131 in the region corresponding to the third color resist layer 113b are in a reflective state; and the first cholesteric liquid crystal molecules 131 in the region corresponding to the second color resist layer 113a are controlled to stand vertically or be in a disordered tilted state, so that the first cholesteric liquid crystal molecules 131 in the region corresponding to the second color resist layer 113a are in a transparent state or a foggy state; at this time, the first pixel unit P1 in the region corresponding to the third color resist layer 113b reflects the third color light (green light) through the first cholesteric liquid crystal molecules 131 and is emitted from the third color resist layer 113b.

[0059] Figure 11 This is a schematic diagram of the reflective display device in Embodiment 1 of the present invention when displaying a color image. Figure 11 As shown, when the reflective display device displays a color image or a pure white image, it controls the brightness of each of the second pixel units P2 and the corresponding first pixel unit P1. Through the principle of mixing red, green and blue light, various colors of light are formed, thereby realizing the display of a color or pure white image.

[0060] In the dark state, the second cholesteric liquid crystal molecules 231 in the region corresponding to the second pixel unit P2 are both in a transparent state or a hazy state, and the first cholesteric liquid crystal molecules 131 in the region corresponding to the first pixel unit P1 are both in a transparent state or a hazy state. At this time, light passes directly through the first cholesteric liquid crystal layer 13 and the second cholesteric liquid crystal layer 23. Figure 12 This is a schematic diagram of the reflective display device in Embodiment 1 of the present invention when displaying a pure black image. Figure 12As shown, the second cholesteric liquid crystal molecules 231 in the region corresponding to the second pixel unit P2 are all in a vertical standing posture or in a disordered tilted state, so that the second cholesteric liquid crystal molecules 231 in the region corresponding to the second pixel unit P2 are all in a transparent state or a hazy state. Similarly, the first cholesteric liquid crystal molecules 131 in the region corresponding to the first pixel unit P1 are all in a vertical standing posture or in a disordered tilted state, so that the first cholesteric liquid crystal molecules 131 in the region corresponding to the first pixel unit P1 are all in a transparent state or a hazy state. At this time, light passes directly through the first cholesteric liquid crystal layer 13 and the second cholesteric liquid crystal layer 23 and is absorbed by the light-absorbing layer 30, resulting in a black or hazy black color.

[0061] [Example 2] Figure 13 This is one of the structural schematic diagrams of the reflective display device in its initial state in Embodiment 2 of the present invention. Figure 14 This is the second schematic diagram of the reflective display device in its initial state according to Embodiment 2 of the present invention. Figure 13 and Figure 14 As shown, the reflective display device and driving method provided in Embodiment 2 of the present invention are the same as those in Embodiment 1. Figures 1 to 12 The reflective display devices and driving methods in the above are basically the same, the difference being: In this embodiment, as Figure 13 As shown, the first color is red, and one of the second and third colors is blue, while the other is green; for example, the first cholesteric liquid crystal molecule 131 is a cyan cholesteric liquid crystal molecule, the second cholesteric liquid crystal molecule 231 is a red cholesteric liquid crystal molecule, the second dye liquid crystal molecule 232 is a red dye liquid crystal molecule, the second color resist layer 113a is a green color resist, and the third color resist layer 113b is a blue color resist. Alternatively, in other embodiments, the first cholesteric liquid crystal molecule 131 is a cyan cholesteric liquid crystal molecule, the second cholesteric liquid crystal molecule 231 is a red cholesteric liquid crystal molecule, the second dye liquid crystal molecule 232 is a red dye liquid crystal molecule, the second color resist layer 113a is a blue color resist, and the third color resist layer 113b is a green color resist.

[0062] Of course, such as Figure 14As shown, the first color can also be green, and one of the second and third colors can be red, while the other can be blue; for example, the first cholesteric liquid crystal molecule 131 is a purple cholesteric liquid crystal molecule, the second cholesteric liquid crystal molecule 231 is a green cholesteric liquid crystal molecule, the second dye liquid crystal molecule 232 is a green dye liquid crystal molecule, the second color resist layer 113a is a red color resist, and the third color resist layer 113b is a blue color resist. Alternatively, in other embodiments, the first cholesteric liquid crystal molecule 131 is a purple cholesteric liquid crystal molecule, the second cholesteric liquid crystal molecule 231 is a green cholesteric liquid crystal molecule, the second dye liquid crystal molecule 232 is a green dye liquid crystal molecule, the second color resist layer 113a is a blue color resist, and the third color resist layer 113b is a red color resist.

[0063] Those skilled in the art should understand that the remaining structures and working principles of this embodiment are the same as those of Embodiment 1, and will not be repeated here.

[0064] [Example 3] Figure 15 This is a schematic diagram of the reflective display device in its initial state according to Embodiment 3 of the present invention. Figure 16 This is a schematic diagram of the planar structure of the second array substrate in Embodiment 3 of the present invention. Figure 15 and Figure 16 As shown, the reflective display device and driving method provided in Embodiment 3 of the present invention are the same as those in Embodiment 1. Figures 1 to 12 Example 2 Figure 13 and Figure 14 The reflective display devices and driving methods in the above are basically the same, the difference being: In this embodiment, the first pixel unit P1 and the second pixel unit P2 correspond one-to-one, that is, the projection of the second pixel electrode 221 on the first array substrate 12 corresponds one-to-one with the first pixel electrode 121. The third color resist layer 113b is disposed on the first opposing substrate 11, and the second color resist layer 113a is disposed on the second opposing substrate 21. The area of ​​the first opposing substrate 11 corresponding to the second color resist layer 113a is transparent, and the area of ​​the second opposing substrate 21 corresponding to the third color resist layer 113b is transparent. Compared to Embodiment 1, this embodiment sets the aperture ratio of the first pixel unit P1 and the second pixel unit P2 to be the same, thereby reducing the brightness difference between the first color light, the second color light, and the third color light, and improving the display effect.

[0065] like Figure 16As shown, the second array substrate 22 is provided with multiple second scan lines 201 and multiple second data lines 202. The multiple second scan lines 201 and multiple second data lines 202 are mutually insulated and intersecting to form multiple second pixel units P2. The second array substrate 22 provides a second thin film transistor 203 and a second pixel electrode 221 in each second pixel unit P2. The second pixel electrode 221 is electrically connected to the second scan line 201 and the second data line 202 adjacent to the second thin film transistor 203 through the second thin film transistor 203. The second thin film transistor 203 includes a second gate, a second active layer, a second drain, and a second source. The second gate and the second scan line 201 are located on the same layer and are electrically connected. The second gate and the second active layer are isolated by an insulating layer. The second source is electrically connected to the second data line 202. The second drain is electrically connected to the second pixel electrode 221 through a contact hole.

[0066] Optionally, the projections of the first scan line 101 and the second scan line 201 on the second array substrate 22 overlap, the projections of the first data line 102 and the second data line 202 on the second array substrate 22 overlap, the projections of the first thin film transistor 103 and the second thin film transistor 203 on the second array substrate 22 overlap, and the projections of the first pixel electrode 121 and the second pixel electrode 221 on the second array substrate 22 overlap.

[0067] This application also provides a driving method for a reflective display device, used to drive the reflective display device as described above. The driving method includes: When displaying the first color, the first cholesteric liquid crystal molecule 131 and the second cholesteric liquid crystal molecule 231 in the region corresponding to the second color resist layer 113a are both in a transparent state or a hazy state, the second cholesteric liquid crystal molecule 231 in the region corresponding to the third color resist layer 113b is in a reflective state, and the first cholesteric liquid crystal molecule 131 in the region corresponding to the third color resist layer 113b is in a transparent state or a hazy state. At this time, the second pixel unit P2 corresponding to the third color resist layer 113b reflects the first color light. Figure 17 This is a schematic diagram of the reflective display device in Embodiment 3 of the present invention when displaying a pure blue image. Figure 17As shown, when displaying the first color (blue), the first cholesteric liquid crystal molecules 131 and the second cholesteric liquid crystal molecules 231 in the corresponding area of ​​the second color resist layer 113a are controlled to be either vertically upright or randomly tilted, making both the first cholesteric liquid crystal molecules 131 and the second cholesteric liquid crystal molecules 231 in the corresponding area of ​​the second color resist layer 113a transparent or hazy; the second cholesteric liquid crystal molecules 231 in the corresponding area of ​​the third color resist layer 113b are controlled to be horizontally lying down, making them reflective; and the first cholesteric liquid crystal molecules 131 in the corresponding area of ​​the third color resist layer 113b are controlled to be either vertically upright or randomly tilted, making them transparent or hazy. At this time, the second pixel unit P2 corresponding to the third color resist layer 113b reflects the first color light (blue light).

[0068] When displaying the second color, the second cholesteric liquid crystal molecule 231 in the region corresponding to the second pixel unit P2 is controlled to be in a transparent or hazy state, the first cholesteric liquid crystal molecule 131 in the region corresponding to the second color resist layer 113a is controlled to be in a reflective state, and the first cholesteric liquid crystal molecule 131 in the region corresponding to the third color resist layer 113b is controlled to be in a transparent or hazy state. At this time, the first pixel unit P1 in the region corresponding to the second color resist layer 113a reflects the second color light. Figure 18 This is a schematic diagram of the reflective display device in Embodiment 3 of the present invention when displaying a pure red image. Figure 18 As shown, when displaying the second color (red), the second cholesteric liquid crystal molecules 231 in the region corresponding to the second pixel unit P2 are controlled to stand vertically or be in a disordered tilted state, so that the second cholesteric liquid crystal molecules 231 in the region corresponding to the second pixel unit P2 are in a transparent state or a hazy state; the first cholesteric liquid crystal molecules 131 in the region corresponding to the second color resist layer 113a are controlled to lie flat, so that the first cholesteric liquid crystal molecules 131 in the region corresponding to the second color resist layer 113a are in a reflective state; and the first cholesteric liquid crystal molecules 131 in the region corresponding to the third color resist layer 113b are controlled to stand vertically or be in a disordered tilted state, so that the first cholesteric liquid crystal molecules 131 in the region corresponding to the third color resist layer 113b are in a transparent state or a hazy state; at this time, the first pixel unit P1 in the region corresponding to the second color resist layer 113a reflects the second color light (red light) through the first cholesteric liquid crystal molecules 131 and is emitted from the second color resist layer 113a.

[0069] When displaying the third color, the second cholesteric liquid crystal molecule 231 in the region corresponding to the second pixel unit P2 is controlled to be in a transparent or hazy state, the first cholesteric liquid crystal molecule 131 in the region corresponding to the third color resist layer 113b is controlled to be in a reflective state, and the first cholesteric liquid crystal molecule 131 in the region corresponding to the second color resist layer 113a is controlled to be in a transparent or hazy state. At this time, the first pixel unit P1 in the region corresponding to the third color resist layer 113b reflects the third color light. Figure 19 This is a schematic diagram of the reflective display device in Embodiment 3 of the present invention when displaying a pure green image. Figure 19 As shown, when displaying the third color (green), the second cholesteric liquid crystal molecules 231 in the region corresponding to the second pixel unit P2 are controlled to stand vertically or be in a disordered tilted state, so that the second cholesteric liquid crystal molecules 231 in the region corresponding to the second pixel unit P2 are in a transparent state or a foggy state; the first cholesteric liquid crystal molecules 131 in the region corresponding to the third color resist layer 113b are controlled to lie flat, so that the first cholesteric liquid crystal molecules 131 in the region corresponding to the third color resist layer 113b are in a reflective state; and the first cholesteric liquid crystal molecules 131 in the region corresponding to the second color resist layer 113a are controlled to stand vertically or be in a disordered tilted state, so that the first cholesteric liquid crystal molecules 131 in the region corresponding to the second color resist layer 113a are in a transparent state or a foggy state; at this time, the first pixel unit P1 in the region corresponding to the third color resist layer 113b reflects the third color light (green light) through the first cholesteric liquid crystal molecules 131 and is emitted from the third color resist layer 113b.

[0070] Figure 20 This is a schematic diagram of the reflective display device in Embodiment 3 of the present invention when displaying a color image. Figure 20 As shown, when the reflective display device displays a color image or a pure white image, it controls the brightness of each of the second pixel units P2 and the corresponding first pixel unit P1. Through the principle of mixing red, green and blue light, various colors of light are formed, thereby realizing the display of a color or pure white image.

[0071] In the dark state, the second cholesteric liquid crystal molecules 231 in the region corresponding to the second pixel unit P2 are both in a transparent state or a hazy state, and the first cholesteric liquid crystal molecules 131 in the region corresponding to the first pixel unit P1 are both in a transparent state or a hazy state. At this time, light passes directly through the first cholesteric liquid crystal layer 13 and the second cholesteric liquid crystal layer 23. Figure 21 This is a schematic diagram of the reflective display device in Embodiment 3 of the present invention when displaying a pure black image. Figure 21As shown, the second cholesteric liquid crystal molecules 231 in the region corresponding to the second pixel unit P2 are all in a vertical standing posture or in a disordered tilted state, so that the second cholesteric liquid crystal molecules 231 in the region corresponding to the second pixel unit P2 are all in a transparent state or a hazy state. Similarly, the first cholesteric liquid crystal molecules 131 in the region corresponding to the first pixel unit P1 are all in a vertical standing posture or in a disordered tilted state, so that the first cholesteric liquid crystal molecules 131 in the region corresponding to the first pixel unit P1 are all in a transparent state or a hazy state. At this time, light passes directly through the first cholesteric liquid crystal layer 13 and the second cholesteric liquid crystal layer 23 and is absorbed by the light-absorbing layer 30, resulting in a black or hazy black color.

[0072] Those skilled in the art should understand that the remaining structures and working principles of this embodiment are the same as those of Embodiment 1 and Embodiment 2, and will not be repeated here.

[0073] [Example 4] Figure 22 This is a schematic diagram of the reflective display device in its initial state according to Embodiment 4 of the present invention. Figure 22 As shown, the reflective display device and driving method provided in Embodiment 4 of the present invention are the same as those in Embodiment 1. Figures 1 to 12 Example 2 Figure 13 and Figure 14 The reflective display devices and driving methods in the above are basically the same, the difference being: In this embodiment, the first pixel unit P1 and the second pixel unit P2 correspond one-to-one, that is, the projection of the second pixel electrode 221 on the first array substrate 12 corresponds one-to-one with the first pixel electrode 121. A second color resist layer 113a is disposed on the first opposing substrate 11, and a third color resist layer 113b is disposed on the second opposing substrate 21. The first opposing substrate 11 is transparent in the area corresponding to the third color resist layer 113b, and the second opposing substrate 21 is transparent in the area corresponding to the second color resist layer 113a. Compared to Embodiment 1, this embodiment sets the aperture ratio of the first pixel unit P1 and the second pixel unit P2 to be the same, thereby reducing the brightness difference between the first color light, the second color light, and the third color light, and improving the display effect.

[0074] refer to Figure 16As shown, the second array substrate 22 is provided with multiple second scan lines 201 and multiple second data lines 202. The multiple second scan lines 201 and multiple second data lines 202 are mutually insulated and intersecting to form multiple second pixel units P2. The second array substrate 22 provides a second thin film transistor 203 and a second pixel electrode 221 in each second pixel unit P2. The second pixel electrode 221 is electrically connected to the second scan line 201 and the second data line 202 adjacent to the second thin film transistor 203 through the second thin film transistor 203. The second thin film transistor 203 includes a second gate, a second active layer, a second drain, and a second source. The second gate and the second scan line 201 are located on the same layer and are electrically connected. The second gate and the second active layer are isolated by an insulating layer. The second source is electrically connected to the second data line 202. The second drain is electrically connected to the second pixel electrode 221 through a contact hole.

[0075] Optionally, the projections of the first scan line 101 and the second scan line 201 on the second array substrate 22 overlap, the projections of the first data line 102 and the second data line 202 on the second array substrate 22 overlap, the projections of the first thin film transistor 103 and the second thin film transistor 203 on the second array substrate 22 overlap, and the projections of the first pixel electrode 121 and the second pixel electrode 221 on the second array substrate 22 overlap.

[0076] This application also provides a driving method for a reflective display device, used to drive the reflective display device as described above. The driving method includes: When displaying the first color, the first cholesteric liquid crystal molecules 131 and the second cholesteric liquid crystal molecules 231 in the region corresponding to the third color resist layer 113b are controlled to be either transparent or hazy. The second cholesteric liquid crystal molecules 231 in the region corresponding to the second color resist layer 113a are controlled to be in a reflective state, and the first cholesteric liquid crystal molecules 131 in the region corresponding to the second color resist layer 113a are controlled to be either transparent or hazy. At this time, the second pixel unit P2 corresponding to the second color resist layer 113a reflects the first color light. (Reference) Figure 17As shown, when displaying the first color (blue), the first cholesteric liquid crystal molecules 131 and the second cholesteric liquid crystal molecules 231 in the region corresponding to the third color resist layer 113b are controlled to be either vertically upright or randomly tilted, making both the first cholesteric liquid crystal molecules 131 and the second cholesteric liquid crystal molecules 231 in the region corresponding to the third color resist layer 113b transparent or hazy; the second cholesteric liquid crystal molecules 231 in the region corresponding to the second color resist layer 113a are controlled to be horizontally lying down, making them reflective; and the first cholesteric liquid crystal molecules 131 in the region corresponding to the second color resist layer 113a are controlled to be either vertically upright or randomly tilted, making them transparent or hazy. At this time, the second pixel unit P2 corresponding to the second color resist layer 113a reflects the first color light (blue light).

[0077] When displaying the second color, the second cholesteric liquid crystal molecules 231 in the region corresponding to the second pixel unit P2 are controlled to be in a transparent or hazy state; the first cholesteric liquid crystal molecules 131 in the region corresponding to the second color resist layer 113a are controlled to be in a reflective state; and the first cholesteric liquid crystal molecules 131 in the region corresponding to the third color resist layer 113b are controlled to be in a transparent or hazy state. At this time, the first pixel unit P1 in the region corresponding to the second color resist layer 113a reflects the second color light. (Reference) Figure 18 As shown, when displaying the second color (red), the second cholesteric liquid crystal molecules 231 in the region corresponding to the second pixel unit P2 are controlled to stand vertically or be in a disordered tilted state, so that the second cholesteric liquid crystal molecules 231 in the region corresponding to the second pixel unit P2 are in a transparent state or a hazy state; the first cholesteric liquid crystal molecules 131 in the region corresponding to the second color resist layer 113a are controlled to lie flat, so that the first cholesteric liquid crystal molecules 131 in the region corresponding to the second color resist layer 113a are in a reflective state; and the first cholesteric liquid crystal molecules 131 in the region corresponding to the third color resist layer 113b are controlled to stand vertically or be in a disordered tilted state, so that the first cholesteric liquid crystal molecules 131 in the region corresponding to the third color resist layer 113b are in a transparent state or a hazy state; at this time, the first pixel unit P1 in the region corresponding to the second color resist layer 113a reflects the second color light (red light) through the first cholesteric liquid crystal molecules 131 and is emitted from the second color resist layer 113a.

[0078] When displaying the third color, the second cholesteric liquid crystal molecules 231 in the region corresponding to the second pixel unit P2 are controlled to be in a transparent or hazy state; the first cholesteric liquid crystal molecules 131 in the region corresponding to the third color resist layer 113b are controlled to be in a reflective state; and the first cholesteric liquid crystal molecules 131 in the region corresponding to the second color resist layer 113a are controlled to be in a transparent or hazy state. At this time, the first pixel unit P1 in the region corresponding to the third color resist layer 113b reflects the third color light. (Reference) Figure 19 As shown, when displaying the third color (green), the second cholesteric liquid crystal molecules 231 in the region corresponding to the second pixel unit P2 are controlled to stand vertically or be in a disordered tilted state, so that the second cholesteric liquid crystal molecules 231 in the region corresponding to the second pixel unit P2 are in a transparent state or a foggy state; the first cholesteric liquid crystal molecules 131 in the region corresponding to the third color resist layer 113b are controlled to lie flat, so that the first cholesteric liquid crystal molecules 131 in the region corresponding to the third color resist layer 113b are in a reflective state; and the first cholesteric liquid crystal molecules 131 in the region corresponding to the second color resist layer 113a are controlled to stand vertically or be in a disordered tilted state, so that the first cholesteric liquid crystal molecules 131 in the region corresponding to the second color resist layer 113a are in a transparent state or a foggy state; at this time, the first pixel unit P1 in the region corresponding to the third color resist layer 113b reflects the third color light (green light) through the first cholesteric liquid crystal molecules 131 and is emitted from the third color resist layer 113b.

[0079] refer to Figure 20 As shown, when the reflective display device displays a color image or a pure white image, it controls the brightness of each of the second pixel units P2 and the corresponding first pixel unit P1. Through the principle of mixing red, green and blue light, various colors of light are formed, thereby realizing the display of a color or pure white image.

[0080] In the dark state, the second cholesteric liquid crystal molecules 231 in the region corresponding to the second pixel unit P2 are controlled to be either transparent or hazy, and the first cholesteric liquid crystal molecules 131 in the region corresponding to the first pixel unit P1 are also controlled to be either transparent or hazy. At this time, light passes directly through the first cholesteric liquid crystal layer 13 and the second cholesteric liquid crystal layer 23. (Reference) Figure 21As shown, the second cholesteric liquid crystal molecules 231 in the region corresponding to the second pixel unit P2 are all in a vertical standing posture or in a disordered tilted state, so that the second cholesteric liquid crystal molecules 231 in the region corresponding to the second pixel unit P2 are all in a transparent state or a hazy state. Similarly, the first cholesteric liquid crystal molecules 131 in the region corresponding to the first pixel unit P1 are all in a vertical standing posture or in a disordered tilted state, so that the first cholesteric liquid crystal molecules 131 in the region corresponding to the first pixel unit P1 are all in a transparent state or a hazy state. At this time, light passes directly through the first cholesteric liquid crystal layer 13 and the second cholesteric liquid crystal layer 23 and is absorbed by the light-absorbing layer 30, resulting in a black or hazy black color.

[0081] Those skilled in the art should understand that the remaining structures and working principles of this embodiment are the same as those of Embodiment 1 and Embodiment 2, and will not be repeated here.

[0082] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content without departing from the scope of the technical solution of the present invention, which are equivalent embodiments with equivalent changes. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the technical solution of the present invention shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. A reflective display device, characterized in that, The system includes a first liquid crystal cell (10) and a second liquid crystal cell (20) stacked on the light-emitting side of the first liquid crystal cell (10). The first liquid crystal cell (10) has a plurality of first pixel units (P1) arranged in an array, and the second liquid crystal cell (20) has a plurality of second pixel units (P2) arranged in an array. Each second pixel unit (P2) corresponds to at least one first pixel unit (P1). The first liquid crystal cell (10) includes a first opposing substrate (11), a first array substrate (12) disposed opposite to the first opposing substrate (11), and a first cholesteric liquid crystal layer (13) located between the first opposing substrate (11) and the first array substrate (12). The first opposing substrate (11) is located on the side of the first liquid crystal cell (10) facing the second liquid crystal cell (20). The first cholesteric liquid crystal layer (13) includes first cholesteric liquid crystal molecules (131). The first cholesteric liquid crystal molecules (131) reflect light of the same color in the reflective state. The first array substrate (12) is provided with a first pixel electrode (121) corresponding to the first pixel unit (P1). The first opposing substrate (11) is provided with a first common electrode (111) cooperating with the first pixel electrode (121). The second liquid crystal cell (20) includes a second opposing substrate (21), a second array substrate (22) disposed opposite to the second opposing substrate (21), and a second cholesteric liquid crystal layer (23) located between the second opposing substrate (21) and the second array substrate (22). The second cholesteric liquid crystal layer (23) includes second cholesteric liquid crystal molecules (231). The second cholesteric liquid crystal molecules (231) reflect light of the same color in the reflective state. The second array substrate (22) is provided with a second pixel electrode (221) corresponding to the second pixel unit (P2). The second opposing substrate (21) is provided with a second common electrode (211) cooperating with the second pixel electrode (212). The second cholesteric liquid crystal molecule (231) reflects the first color light in the reflective state, and the first cholesteric liquid crystal molecule (131) reflects the complementary color light of the first color light in the reflective state. The reflective display device is provided with a second color resist layer (113a) and a third color resist layer (113b). The projections of the second color resist layer (113a) and the third color resist layer (113b) on the reflective display device are completely staggered, and at least one of them is provided on the first opposing substrate (11). The filtering wavelength of the second color resist layer (113a) and the filtering wavelength of the third color resist layer (113b) both partially overlap with the wavelength of the complementary color light.

2. The reflective display device according to claim 1, characterized in that, Each second pixel unit (P2) corresponds to two first pixel units (P1) of different colors. The second color resist layer (113a) and the third color resist layer (113b) are both disposed on the first opposing substrate (11) and each corresponds to a different first pixel unit (P1). The second opposing substrate (21) is transparent in the area corresponding to the second pixel unit (P2).

3. The reflective display device according to claim 1, characterized in that, The first pixel unit (P1) and the second pixel unit (P2) correspond one-to-one. The second opposing substrate (21) is located on the side of the second liquid crystal cell (20) away from the first liquid crystal cell (10). The third color resist layer (113b) is disposed on the first opposing substrate (11), and the second color resist layer (113a) is disposed on the second opposing substrate (21). The first opposing substrate (11) is transparent in the area corresponding to the second color resist layer (113a), and the second opposing substrate (21) is transparent in the area corresponding to the third color resist layer (113b).

4. The reflective display device according to claim 1, characterized in that, The first pixel unit (P1) and the second pixel unit (P2) correspond one-to-one. The second opposing substrate (21) is located on the side of the second liquid crystal cell (20) away from the first liquid crystal cell (10). The second color resist layer (113a) is disposed on the first opposing substrate (11), and the third color resist layer (113b) is disposed on the second opposing substrate (21). The first opposing substrate (11) is transparent in the area corresponding to the third color resist layer (113b), and the second opposing substrate (21) is transparent in the area corresponding to the second color resist layer (113a).

5. The reflective display device according to any one of claims 1-4, characterized in that, The first color is blue, and one of the second and third colors is red, while the other is green; Alternatively, the first color is red, and one of the second and third colors is blue, while the other is green; Alternatively, the first color is green, and one of the second and third colors is red, while the other is blue.

6. The reflective display device according to any one of claims 1-4, characterized in that, The reflective display device includes a light-absorbing layer (30) that is disposed on the side of the first liquid crystal cell (10) away from the second liquid crystal cell (20) and is used to absorb light passing through the first liquid crystal cell (10) and the second liquid crystal cell (20).

7. The reflective display device according to any one of claims 1-4, characterized in that, The first opposing substrate (11) is provided with a first black matrix (112), which is used to separate the plurality of first pixel units (P1) from each other; The second opposing substrate (21) is provided with a second black matrix (212), which is used to separate multiple second pixel units (P2) from each other.

8. A driving method for a reflective display device, characterized in that, The driving method for driving the reflective display device as described in claim 2 includes: When displaying the first color, the second cholesteric liquid crystal molecule (231) in the corresponding area of ​​the second pixel unit (P2) is controlled to be in a reflective state and the first cholesteric liquid crystal molecule (131) in the corresponding area is in a transparent state or a hazy state. At this time, the second pixel unit (P2) reflects the first color light. When displaying the second color, the second cholesteric liquid crystal molecules (231) in the region corresponding to the second pixel unit (P2) are controlled to be in a transparent or hazy state, the first cholesteric liquid crystal molecules (131) in the region corresponding to the second color resist layer (113a) are controlled to be in a reflective state, and the first cholesteric liquid crystal molecules (131) in the region corresponding to the third color resist layer (113b) are controlled to be in a transparent or hazy state. At this time, the first pixel unit (P1) in the region corresponding to the second color resist layer (113a) reflects the second color light. When displaying the third color, the second cholesteric liquid crystal molecule (231) in the region corresponding to the second pixel unit (P2) is controlled to be in a transparent or hazy state, the first cholesteric liquid crystal molecule (131) in the region corresponding to the third color resist layer (113b) is controlled to be in a reflective state, and the first cholesteric liquid crystal molecule (131) in the region corresponding to the second color resist layer (113a) is controlled to be in a transparent or hazy state. At this time, the first pixel unit (P1) in the region corresponding to the third color resist layer (113b) reflects the third color light. In the dark state, the second cholesteric liquid crystal molecules (231) in the region corresponding to the second pixel unit (P2) are controlled to be either transparent or hazy, and the first cholesteric liquid crystal molecules (131) in the region corresponding to the first pixel unit (P1) are controlled to be either transparent or hazy. At this time, light passes directly through the first cholesteric liquid crystal layer (13) and the second cholesteric liquid crystal layer (23).

9. A driving method for a reflective display device, characterized in that, The driving method for driving the reflective display device as described in claim 3 includes: When displaying the first color, the first cholesteric liquid crystal molecules (131) and the second cholesteric liquid crystal molecules (231) in the region corresponding to the second color resist layer (113a) are controlled to be in a transparent or hazy state, the second cholesteric liquid crystal molecules (231) in the region corresponding to the third color resist layer (113b) are controlled to be in a reflective state, and the first cholesteric liquid crystal molecules (131) in the region corresponding to the third color resist layer (113b) are controlled to be in a transparent or hazy state. At this time, the second pixel unit (P2) corresponding to the third color resist layer (113b) reflects the first color light. When displaying the second color, the second cholesteric liquid crystal molecules (231) in the region corresponding to the second pixel unit (P2) are controlled to be in a transparent or hazy state, the first cholesteric liquid crystal molecules (131) in the region corresponding to the second color resist layer (113a) are controlled to be in a reflective state, and the first cholesteric liquid crystal molecules (131) in the region corresponding to the third color resist layer (113b) are controlled to be in a transparent or hazy state. At this time, the first pixel unit (P1) in the region corresponding to the second color resist layer (113a) reflects the second color light. When displaying the third color, the second cholesteric liquid crystal molecule (231) in the region corresponding to the second pixel unit (P2) is controlled to be in a transparent or hazy state, the first cholesteric liquid crystal molecule (131) in the region corresponding to the third color resist layer (113b) is controlled to be in a reflective state, and the first cholesteric liquid crystal molecule (131) in the region corresponding to the second color resist layer (113a) is controlled to be in a transparent or hazy state. At this time, the first pixel unit (P1) in the region corresponding to the third color resist layer (113b) reflects the third color light. In the dark state, the second cholesteric liquid crystal molecules (231) in the region corresponding to the second pixel unit (P2) are controlled to be either transparent or hazy, and the first cholesteric liquid crystal molecules (131) in the region corresponding to the first pixel unit (P1) are controlled to be either transparent or hazy. At this time, light passes directly through the first cholesteric liquid crystal layer (13) and the second cholesteric liquid crystal layer (23).

10. A driving method for a reflective display device, characterized in that, The driving method for driving the reflective display device as described in claim 4 includes: When displaying the first color, the first cholesteric liquid crystal molecules (131) and the second cholesteric liquid crystal molecules (231) in the region corresponding to the third color resist layer (113b) are controlled to be in a transparent or hazy state, the second cholesteric liquid crystal molecules (231) in the region corresponding to the second color resist layer (113a) are controlled to be in a reflective state, and the first cholesteric liquid crystal molecules (131) in the region corresponding to the second color resist layer (113a) are controlled to be in a transparent or hazy state. At this time, the second pixel unit (P2) corresponding to the second color resist layer (113a) reflects the first color light. When displaying the second color, the second cholesteric liquid crystal molecules (231) in the region corresponding to the second pixel unit (P2) are controlled to be in a transparent or hazy state, the first cholesteric liquid crystal molecules (131) in the region corresponding to the second color resist layer (113a) are controlled to be in a reflective state, and the first cholesteric liquid crystal molecules (131) in the region corresponding to the third color resist layer (113b) are controlled to be in a transparent or hazy state. At this time, the first pixel unit (P1) in the region corresponding to the second color resist layer (113a) reflects the second color light. When displaying the third color, the second cholesteric liquid crystal molecule (231) in the region corresponding to the second pixel unit (P2) is controlled to be in a transparent or hazy state, the first cholesteric liquid crystal molecule (131) in the region corresponding to the third color resist layer (113b) is controlled to be in a reflective state, and the first cholesteric liquid crystal molecule (131) in the region corresponding to the second color resist layer (113a) is controlled to be in a transparent or hazy state. At this time, the first pixel unit (P1) in the region corresponding to the third color resist layer (113b) reflects the third color light. In the dark state, the second cholesteric liquid crystal molecules (231) in the region corresponding to the second pixel unit (P2) are controlled to be either transparent or hazy, and the first cholesteric liquid crystal molecules (131) in the region corresponding to the first pixel unit (P1) are controlled to be either transparent or hazy. At this time, light passes directly through the first cholesteric liquid crystal layer (13) and the second cholesteric liquid crystal layer (23).

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