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, and the reflective display device is provided with a first color pixel unit, a second color pixel unit and a third color pixel unit; a color film substrate of the first liquid crystal box is in a transparent state in an area corresponding to a first color pixel unit, and a second color resistance layer and a third color resistance layer corresponding to a third color pixel unit are arranged in an area corresponding to a second color pixel unit; one of first cholesteric liquid crystal molecules of the first liquid crystal box and second cholesteric liquid crystal molecules of the second liquid crystal box reflects first color light in a reflection state, and the other one reflects complementary color light of the first color light in the reflection state; 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.

Description

Technical Field

[0001] The present invention relates to the technical field of displays, and in particular to a reflective display device and a driving method. Background Art

[0002] Display panels are thin, durable, and energy-saving and environmentally friendly with low power consumption, but they need to be used with a backlight, resulting in thick modules and high costs. Electronic paper displays (reflective displays) have become a type of display that meets the needs of the public. Electronic paper displays can use external light sources to display images, unlike LCD displays that require backlights. Therefore, in outdoor environments with strong sunlight, the information on the electronic paper can still be clearly seen without viewing angle issues. In addition, electronic paper displays are now widely used in electronic readers (such as e-books, e-newspapers) or other electronic components (such as price tags) due to their advantages such as power saving, high reflectivity and contrast ratio.

[0003] Existing electronic paper displays usually use 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, micro-electromechanical system (MEMS) technology or electrowetting technology. However, compared with liquid crystal display technology, existing electronic paper display technology is not very mature, mass production efficiency is low, manufacturing cost is relatively high, and existing electronic paper displays cannot achieve color display.

[0004] In the prior art, the reflective display device using cholesteric liquid crystal can only reflect one color and transmit light of other colors due to the requirements of the cholesteric liquid crystal pitch. Therefore, the reflective display device of the single-layer cholesteric liquid crystal is mostly displayed in the form of black text on a yellow background, yellow text on a black background, red text on a black background, or black text on a red background, and cannot achieve a display of white text on a black background or black text on a white background like a book, which is greatly limited in product application; and the color of the light reflected by the cholesteric liquid crystal is poor, which affects the display effect. Figure 1 Schematic diagram of the structure of a reflective display device using a three-layer cholesteric liquid crystal cell in the prior art. Figure 1 As shown, if white display or color display is required, the reflective display device needs to use a three-layer cholesteric liquid crystal box to reflect red / green / blue light respectively, so as to achieve white display and color display. However, the three-layer cholesteric liquid crystal box not only has a large box thickness, but also has a high cost. Summary of the invention

[0005] In order to overcome the shortcomings and deficiencies in the prior art, an object of the present invention is to provide a reflective display device and a driving method to solve the problem of poor reflection color of the reflective display device of the single-layer cholesteric liquid crystal in the prior art.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] The present invention provides a reflective display device, comprising a first liquid crystal box and a second liquid crystal box stacked on the light incident side of the first liquid crystal box, wherein the reflective display device has a plurality of pixel units distributed in an array, wherein the plurality of pixel units include a first color pixel unit, a second color pixel unit and a third color pixel unit;

[0008] The first liquid crystal box comprises a color filter substrate, a first array substrate arranged opposite to the color filter substrate, and a first liquid crystal layer located between the color filter substrate and the first array substrate, the color filter substrate is located on a side of the first liquid crystal box away from the second liquid crystal box, the first liquid crystal layer comprises first cholesteric liquid crystal molecules, the first cholesteric liquid crystal molecules all reflect light of the same color in a reflective state, the color filter substrate is transparent in an area corresponding to the first color pixel unit, a second color color resist layer is provided in an area corresponding to the second color pixel unit, and a third color color resist layer is provided corresponding to the third color pixel unit, a first pixel electrode corresponding to the pixel unit is provided on the first array substrate, and a first common electrode matched with the first pixel electrode is provided on the color filter substrate;

[0009] The second liquid crystal box comprises an opposing substrate, a second array substrate arranged opposite to the opposing substrate, and a second liquid crystal layer located between the opposing substrate and the second array substrate, the second liquid crystal layer comprises second cholesteric liquid crystal molecules, the second cholesteric liquid crystal molecules all reflect light of the same color in a reflective state, a second pixel electrode corresponding to the pixel unit is disposed on the second array substrate, and a second common electrode matched with the second pixel electrode is disposed on the opposing substrate;

[0010] One of the first cholesteric liquid crystal molecules and the second cholesteric liquid crystal molecules reflects a first color light in a reflective state, and the other reflects a complementary color light of the first color light in a reflective state, and the filtering wavelength of the second color color resist layer and the filtering wavelength of the third color color resist layer both partially overlap with the wavelength of the complementary color light.

[0011] Furthermore, the first liquid crystal layer includes first dye liquid crystal molecules that are mixed with the first cholesteric liquid crystal molecules, and the first dye liquid crystal molecules have the same color as the first cholesteric liquid crystal molecules and rotate synchronously with the first cholesteric liquid crystal molecules.

[0012] Furthermore, the second liquid crystal layer includes second dye liquid crystal molecules mixed with the second cholesteric liquid crystal molecules, the second dye liquid crystal molecules are of the same color as the second cholesteric liquid crystal molecules and rotate synchronously with the second cholesteric liquid crystal molecules.

[0013] Further, the first color, the second color, and the third color are each one of red, green, and blue.

[0014] Further, the first cholesteric liquid crystal molecules reflect the first color light in the reflective state, and the second cholesteric liquid crystal molecules reflect the fourth color light in the reflective state; or, the first cholesteric liquid crystal molecules reflect the fourth color light in the reflective state, and the second cholesteric liquid crystal molecules reflect the first color light in the reflective state;

[0015] The first color and the fourth color are complementary colors.

[0016] Furthermore, the reflective display device includes a light absorbing layer disposed on the entire surface, wherein the light absorbing layer is disposed on a side of the second liquid crystal cell away from the first liquid crystal cell and is used to absorb light passing through the first liquid crystal cell and the second liquid crystal cell.

[0017] Furthermore, a black matrix is ​​provided on the color filter substrate, and the black matrix is ​​used to separate the plurality of pixel units from each other.

[0018] The present application also provides a driving method of a reflective display device, which is used to drive the reflective display device as described above, wherein the first cholesteric liquid crystal molecules reflect fourth color light in a reflective state, and the second cholesteric liquid crystal molecules reflect first color light in a reflective state, and the first color and the fourth color are complementary colors, and the driving method comprises:

[0019] When the first color pixel unit is in a bright state, the second cholesteric liquid crystal molecules in the area corresponding to the first color pixel unit are controlled to be in a reflective state, and the first cholesteric liquid crystal molecules in the area corresponding to the first color pixel unit are controlled to be in a transparent state or a foggy state. At this time, the second liquid crystal layer in the area corresponding to the first color pixel unit reflects the first color light; when the first color pixel unit is in a dark state, the first cholesteric liquid crystal molecules and the second cholesteric liquid crystal molecules in the area corresponding to the first color pixel unit are controlled to be in a transparent state or a foggy state. At this time, the light directly passes through the first liquid crystal layer and the second liquid crystal layer;

[0020] When the second color pixel unit is in a bright state, the first cholesteric liquid crystal molecules in the area corresponding to the second color pixel unit are controlled to be in a reflective state, and the second cholesteric liquid crystal molecules in the area corresponding to the second color pixel unit are controlled to be in a transparent state, a foggy state or a reflective state. At this time, the first liquid crystal layer in the area corresponding to the second color pixel unit reflects the second color light; when the second color pixel unit is in a dark state, the first cholesteric liquid crystal molecules in the area corresponding to the second color pixel unit are controlled to be in a transparent state or a foggy state, and the second cholesteric liquid crystal molecules in the area corresponding to the second color pixel unit are controlled to be in a light-transmitting state, a foggy state or a reflective state. At this time, the light directly passes through the first liquid crystal layer and the second liquid crystal layer;

[0021] When the third color pixel unit is in a bright state, the first cholesteric liquid crystal molecules in the area corresponding to the third color pixel unit are controlled to be in a reflective state, and the second cholesteric liquid crystal molecules in the area corresponding to the third color pixel unit are controlled to be in a transparent state, a foggy state or a reflective state. At this time, the first liquid crystal layer in the area corresponding to the third color pixel unit reflects the third color light; when the third color pixel unit is in a dark state, the first cholesteric liquid crystal molecules in the area corresponding to the third color pixel unit are controlled to be in a transparent state or a foggy state, and the second cholesteric liquid crystal molecules in the area corresponding to the third color pixel unit are controlled to be in a translucent state, a foggy state or a reflective state. At this time, the light directly passes through the first liquid crystal layer and the second liquid crystal layer.

[0022] The present application also provides a driving method of a reflective display device, which is used to drive the reflective display device as described above, wherein the first cholesteric liquid crystal molecules reflect a first color light in a reflective state, and the second cholesteric liquid crystal molecules reflect a fourth color light in a reflective state, and the first color and the fourth color are complementary colors, and the driving method comprises:

[0023] When the first color pixel unit is in a bright state, the first cholesteric liquid crystal molecules in the area corresponding to the first color pixel unit are controlled to be in a reflective state, and the second cholesteric liquid crystal molecules in the area corresponding to the first color pixel unit are controlled to be in a transparent state or a foggy state. At this time, the first liquid crystal layer in the area corresponding to the first color pixel unit reflects the first color light; when the first color pixel unit is in a dark state, the first cholesteric liquid crystal molecules and the second cholesteric liquid crystal molecules in the area corresponding to the first color pixel unit are controlled to be in a transparent state or a foggy state. At this time, the light directly passes through the first liquid crystal layer and the second liquid crystal layer;

[0024] When the second color pixel unit is in a bright state, the second cholesteric liquid crystal molecules in the area corresponding to the second color pixel unit are controlled to be in a reflective state, and the first cholesteric liquid crystal molecules in the area corresponding to the second color pixel unit are controlled to be in a transparent state, a foggy state or a reflective state. At this time, the second liquid crystal layer in the area corresponding to the second color pixel unit reflects the second color light; when the second color pixel unit is in a dark state, the second cholesteric liquid crystal molecules in the area corresponding to the second color pixel unit are controlled to be in a transparent state or a foggy state, and the first cholesteric liquid crystal molecules in the area corresponding to the second color pixel unit are controlled to be in a light-transmitting state, a foggy state or a reflective state. At this time, the light directly passes through the first liquid crystal layer and the second liquid crystal layer;

[0025] When the third color pixel unit is in a bright state, the second cholesteric liquid crystal molecules in the area corresponding to the third color pixel unit are controlled to be in a reflective state, and the first cholesteric liquid crystal molecules in the area corresponding to the third color pixel unit are controlled to be in a transparent state, a foggy state or a reflective state. At this time, the second liquid crystal layer in the area corresponding to the third color pixel unit reflects the third color light; when the third color pixel unit is in a dark state, the second cholesteric liquid crystal molecules in the area corresponding to the third color pixel unit are controlled to be in a transparent state or a foggy state, and the first cholesteric liquid crystal molecules in the area corresponding to the third color pixel unit are controlled to be in a translucent state, a foggy state or a reflective state. At this time, the light directly passes through the first liquid crystal layer and the second liquid crystal layer.

[0026] Furthermore, the driving method includes:

[0027] When the reflective display device displays a first color, all the first color pixel units are controlled to be in a bright state, and all the second color pixel units and the third color pixel units are controlled to be in a dark state;

[0028] When the reflective display device displays a second color, all of the first color pixel units and the third color pixel units are controlled to be in a dark state, and all of the second color pixel units are controlled to be in a bright state;

[0029] When the reflective display device displays a third color, all of the first color pixel units and the second color pixel units are controlled to be in a dark state, and all of the third color pixel units are controlled to be in a bright state;

[0030] When the reflective display device displays a color image, all of the first color pixel units, the second color pixel units, and the third color pixel units are controlled to display corresponding brightness.

[0031] The beneficial effects of the present invention are as follows: by arranging a first liquid crystal box and a second liquid crystal box in a reflective display device, the color film substrate of the first liquid crystal box is in a transparent state in an area corresponding to the first color pixel unit, a second color color resist layer is arranged in an area corresponding to the second color pixel unit, and a third color color resist layer is arranged in an area corresponding to the third color pixel unit, and one of the first cholesteric liquid crystal molecules of the first liquid crystal box and the second cholesteric liquid crystal molecules of the second liquid crystal box reflects the first color light in a reflective state, and the other reflects the complementary color light of the first color light in a reflective state, and the filtering wavelength of the second color color resist layer and the filtering wavelength of the third color color resist layer both partially overlap with the wavelength of the complementary color light, so that the reflective display device can realize color display by using dual liquid crystal boxes, the colors are richer, and the box thickness is smaller. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the structure of a reflective display device using a three-layer cholesteric liquid crystal box in the prior art.

[0033] Figure 2 1 is a schematic structural diagram of the reflective display device in the initial state in the first embodiment of the present invention.

[0034] Figure 3 Schematic diagram of the pixel arrangement structure of the reflective display device in the first embodiment of the present invention.

[0035] Figure 4 It is a schematic diagram of the planar structure of the first array substrate in the first embodiment of the present invention.

[0036] Figure 5 It is a schematic diagram of the planar structure of the second array substrate in the first embodiment of the present invention.

[0037] Figure 6 It is a schematic diagram of the principle of the transformation of the three states of the cholesteric liquid crystal in the first embodiment of the present invention.

[0038] Figure 7 It is a schematic diagram of the driving signal for the three-state transformation of the cholesteric liquid crystal in the first embodiment of the present invention.

[0039] Figure 8 This is one of the structural schematic diagrams of the reflective display device in the first embodiment of the present invention when displaying a pure red picture.

[0040] Fig. 9 This is the second structural schematic diagram of the reflective display device in the first embodiment of the present invention when displaying a pure red image.

[0041] Fig.10 This is the third structural schematic diagram of the reflective display device in the first embodiment of the present invention when displaying a pure red image.

[0042] Fig.11This is one of the structural schematic diagrams of the reflective display device in the first embodiment of the present invention when displaying a pure green picture.

[0043] Fig.12 This is the second structural schematic diagram of the reflective display device in the first embodiment of the present invention when displaying a pure green picture.

[0044] Fig.13 This is the third structural schematic diagram of the reflective display device in the first embodiment of the present invention when displaying a pure green picture.

[0045] Fig.14 This is one of the structural schematic diagrams of the reflective display device in the first embodiment of the present invention when displaying a pure blue picture.

[0046] Fig.15 This is the second structural schematic diagram of the reflective display device in the first embodiment of the present invention when displaying a pure blue picture.

[0047] Fig.16 This is the third structural schematic diagram of the reflective display device in the first embodiment of the present invention when displaying a pure blue picture.

[0048] Fig.17 This is one of the structural schematic diagrams of the reflective display device in the first embodiment of the present invention when displaying a pure black picture.

[0049] Fig.18 This is the second structural schematic diagram of the reflective display device in the first embodiment of the present invention when displaying a pure black picture.

[0050] Fig.19 This is the third structural schematic diagram of the reflective display device in the first embodiment of the present invention when displaying a pure black picture.

[0051] Fig. 20 This is one of the structural schematic diagrams of the reflective display device in the first embodiment of the present invention when displaying a color picture.

[0052] Fig.21 This is the second structural schematic diagram of the reflective display device in the first embodiment of the present invention when displaying a color picture.

[0053] Fig. 22 This is the third structural schematic diagram of the reflective display device in the first embodiment of the present invention when displaying a color picture.

[0054] Fig.23 It is a schematic structural diagram of the reflective display device in the initial state in the second embodiment of the present invention.

[0055] Fig.24 This is one of the structural schematic diagrams of the reflective display device in the initial state in the third embodiment of the present invention.

[0056] Fig.25 This is the second structural schematic diagram of the reflective display device in the initial state in the third embodiment of the present invention.

[0057] Fig.26 This is the third structural schematic diagram of the reflective display device in the initial state in the third embodiment of the present invention. DETAILED DESCRIPTION

[0058] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the reflective display device and driving method proposed by the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments:

[0059] [Example 1]

[0060] Figure 2 1 is a schematic structural diagram of the reflective display device in the initial state in the first embodiment of the present invention. Figure 3 Schematic diagram of the pixel arrangement structure of the reflective display device in the first embodiment of the present invention. Figure 4 It is a schematic diagram of the planar structure of the first array substrate in the first embodiment of the present invention. Figure 5 It is a schematic diagram of the planar structure of the second array substrate in the first embodiment of the present invention.

[0061] like Figures 2 to 5 As shown, a reflective display device provided by the first embodiment of the present invention includes a second liquid crystal cell 20 and a first liquid crystal cell 10 stacked on the light-emitting side of the second liquid crystal cell 20, that is, the side of the first liquid crystal cell 10 closer to the external environment than the second liquid crystal cell 20. The reflective display device has a plurality of pixel units P distributed in an array, wherein the plurality of pixel units P include a first color pixel unit P1, a second color pixel unit P2, and a third color pixel unit P3, and each of the first color pixel unit P1, the second color pixel unit P2, and the third color pixel unit P3 is one of a red pixel unit (R), a green pixel unit (G), and a blue pixel unit (B).

[0062] The first liquid crystal cell 10 includes a color filter substrate 11, a first array substrate 12 arranged opposite to the color filter substrate 11, and a first liquid crystal layer 13 located between the color filter substrate 11 and the first array substrate 12. The color filter substrate 11 is located on the side of the first liquid crystal cell 10 away from the second liquid crystal cell 20, and the first array substrate 12 is located on the side of the first liquid crystal cell 10 close to the second liquid crystal cell 20. The first liquid crystal layer 13 includes first cholesteric liquid crystal molecules 131, and the first cholesteric liquid crystal molecules 131 reflect light of the same color in a reflective state. The color filter substrate 11 is transparent in the area corresponding to the first color pixel unit P1, and is provided with a second color color resist layer 113a in the area corresponding to the second color pixel unit P2 and a third color color resist layer 113b in the area corresponding to the third color pixel unit P3. Specifically, for example, the color filter substrate 11 is provided with a transparent color resist W in the area corresponding to the first color pixel unit P1 or covered by a flat layer, and is provided with a second color color resist layer 113a in the area corresponding to the second color pixel unit P2 and a third color color resist layer 113b in the area corresponding to the third color pixel unit P3. In other embodiments, the color filter substrate 11 may not be provided with a transparent color resist W in the area corresponding to the first color pixel unit P1 , which is not limited here.

[0063] Furthermore, a first pixel electrode 121 is provided on the first array substrate 12, and a first pixel electrode 121 is correspondingly provided in each pixel unit P, and the first pixel electrode 121 corresponds to the pixel unit P one by one, and the first pixel electrode 121 is a block electrode corresponding to the pixel unit P. A first common electrode 111 matched with the first pixel electrode 121 is provided on the color filter substrate 11, and the first common electrode 111 is a planar electrode covering the entire surface of the color filter substrate 11.

[0064] The second liquid crystal cell 20 includes an opposing substrate 21, a second array substrate 22 disposed opposite to the opposing substrate 21, and a second liquid crystal layer 23 located between the opposing substrate 21 and the second array substrate 22. The opposing substrate 21 is located on the side of the second liquid crystal cell 20 close to the first liquid crystal cell 10, and the second array substrate 22 is located on the side of the second liquid crystal cell 20 away from the first liquid crystal cell 10; optionally, the opposing substrate 21 can share a substrate with the first array substrate 12, that is, the opposing substrate 21 is reused as the first array substrate 12, thereby reducing the film thickness. The second liquid crystal layer 23 includes second cholesteric liquid crystal molecules 231, and the second cholesteric liquid crystal molecules 231 reflect the same color light in the reflection state. Among them, one of the first cholesteric liquid crystal molecules 131 and the second cholesteric liquid crystal molecules 231 reflects the first color light in the reflection state, and the other reflects the complementary color light of the first color light in the reflection state, and the filtering wavelength of the second color color blocking layer 113a and the filtering wavelength of the third color color blocking layer 113b both overlap with the wavelength of the complementary color light.

[0065] Furthermore, a second pixel electrode 221 is provided on the second array substrate 22, and a second pixel electrode 221 is correspondingly provided in each pixel unit P, and the second pixel electrode 221 corresponds to the pixel unit P one by one, and the second pixel electrode 221 is a block electrode corresponding to the pixel unit P, that is, the first pixel electrode 121 corresponds to the second pixel electrode 221 one by one. A second common electrode 211 matched with the second pixel electrode 212 is provided on the opposing substrate 21, and the second common electrode 211 is a planar electrode covering the entire surface of the opposing substrate 21.

[0066] Among them, the cholesteric liquid crystal molecules (the first cholesteric liquid crystal molecules 131, the second cholesteric liquid crystal molecules 231) have three stable textures: P state (Planar, planar texture state, reflection state), FC state (Focal Conic, focal conic state, fog state) and H state (transparent state). In the P state, the reflection spectrum of the cholesteric liquid crystal is in the visible spectrum, and the cholesteric liquid crystal reflects 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 above colored light, and the light can be scattered and passed through the cholesteric liquid crystal; in the H state, the cholesteric liquid crystal no longer reflects the above colored light, and the light can directly pass through the cholesteric liquid crystal, and it does not have a scattering effect on the light. Under the action of a certain electric field, these three states can be converted to each other.

[0067] Figure 6 It is a schematic diagram of the principle of the transformation of the three states of the cholesteric liquid crystal in the first embodiment of the present invention. Figure 7 It is a schematic diagram of the driving signal for the three-state transformation of the cholesteric liquid crystal in the first embodiment of the present invention.

[0068] Combination Figure 2 , Figure 6 and Figure 7As shown, a common voltage signal Vcom is applied to the common electrodes (the first common electrode 111 and the second common electrode 211), and a first electrical signal V1 is continuously applied to the pixel electrodes (the first pixel electrode 121 and the second pixel electrode 221). There is a voltage difference (about 20V) between the common voltage signal Vcom and the first electrical signal V1, and a strong vertical electric field is formed between the common electrodes and the pixel electrodes, so that the cholesteric liquid crystal molecules rotate and stagnate in the H state (transparent state). A common voltage signal Vcom is applied to the common electrodes (the first common electrode 111 and the second common electrode 211), and a second electric signal V2 is applied to the pixel electrodes (the first pixel electrode 121 and the second pixel electrode 221). There is a voltage difference (for example, 20V) between the second electric signal V2 and the common voltage signal Vcom, and the second electric signal V2 gradually becomes the same as the common voltage signal Vcom within a first preset time, that is, the second electric 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 (the first common electrode 111 and the second common electrode 211), and a third electric signal V3 is applied to the pixel electrodes (the first pixel electrode 121 and the second pixel electrode 221). There is a voltage difference (for example, 30V) between the third electric signal V3 and the common voltage signal Vcom, and the third electric signal V3 directly becomes the same as the common voltage signal Vcom at the second preset time, and the second preset time is less than the first preset time, that is, the third electric signal V3 first has a large voltage difference with the common voltage signal Vcom, and then quickly 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 disappears quickly, causing the cholesteric liquid crystal molecules to rotate and stagnate in the P state, which is a reflective state. Among them, the arrangement directions of the cholesteric liquid crystal molecules are different, the reflected visible light spectra are different, and the remaining spectra are transmitted, and the P state and the FC state do not require voltage to maintain. The reflection spectrum band (Δλ) of the cholesteric liquid crystal molecules is proportional to the helical pitch (Po) and the 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 helical pitches can reflect light of different colors in the reflection state.

[0069] like Figure 4As shown, a plurality of first scan lines 101 and a plurality of first data lines 102 are provided on the first array substrate 12, and the plurality of first scan lines 101 and the plurality of first data lines 102 are insulated from each other and cross to define a plurality of pixel units P. The first array substrate 12 is provided with a first thin film transistor 103 and a first pixel electrode 121 in each pixel unit P, and 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 in the same layer and are electrically connected, the first gate and the first active layer are separated by an insulating layer, the first source is electrically connected to the first data line 102, and the first drain is electrically connected to the first pixel electrode 121 through a contact hole.

[0070] like Figure 5 As shown, a plurality of second scan lines 201 and a plurality of second data lines 202 are provided on the second array substrate 22, and the plurality of second scan lines 201 and the plurality of second data lines 202 are mutually insulated and cross-defined to form a plurality of pixel units P. The second array substrate 22 is provided with a second thin film transistor 203 and a second pixel electrode 221 in each pixel unit P, and 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 is located in the same layer as the second scan line 201 and is electrically connected, the second gate is separated from the second active layer by an insulating layer, the second source is electrically connected to the second data line 202, and the second drain is electrically connected to the second pixel electrode 221 through a contact hole.

[0071] Optionally, the projections of the first scan line 101 and the second scan line 201 on the second array substrate 22 overlap with each other, the projections of the first data line 102 and the second data line 202 on the second array substrate 22 overlap with each other, the projections of the first thin film transistor 103 and the second thin film transistor 203 on the second array substrate 22 overlap with each other, and the projections of the first pixel electrode 121 and the second pixel electrode 221 on the second array substrate 22 overlap with each other.

[0072] In this embodiment, the second liquid crystal layer 23 also includes second dye liquid crystal molecules 232 that are mixed with the second cholesteric liquid crystal molecules 231. The second dye liquid crystal molecules 232 are the same color as the second cholesteric liquid crystal molecules 231 and rotate synchronously with the second cholesteric liquid crystal molecules 231. The second dye liquid crystal molecules 232 use positive dye liquid crystal molecules. The light absorption capacity of the long axis of the positive dye liquid crystal molecules is greater than the light absorption capacity of the short axis. The positive dye liquid crystal molecules have the characteristics of strong light absorption capacity of the long axis and weak light absorption capacity of the short axis. The long axis absorbs part of the light, thereby presenting a color corresponding to the second dye liquid crystal molecules 232. For example, the second dye liquid crystal molecules 232 use purple dye liquid crystal molecules, and the long axis of the purple dye liquid crystal molecules can absorb the green band and present purple; similarly, if it is a red dye liquid crystal molecule, the long axis of the red dye liquid crystal molecule can absorb the cyan band and present red. Of course, the second dye liquid crystal molecules 232 can also use other single-color dye liquid crystal molecules, such as blue, green, yellow, etc.

[0073] In this embodiment, the first cholesteric liquid crystal molecules 131 reflect the fourth color light in the reflection state, and the second cholesteric liquid crystal molecules 231 reflect the first color light in the reflection state. The first color and the fourth color are complementary colors, that is, the first color and the fourth color are mixed with each other to form white. Among them, the first color, the second color and the third color are each one of red, green and blue. In this embodiment, the first cholesteric liquid crystal molecules 131 are cyan cholesteric liquid crystal molecules, the second cholesteric liquid crystal molecules 231 are red cholesteric liquid crystal molecules, the second dye liquid crystal molecules 232 are red dye liquid crystal molecules, the second color color resist layer 113a is green color resist, and the third color color resist layer 113b is blue color resist. Of course, in other embodiments, the first cholesteric liquid crystal molecules 131 are cyan cholesteric liquid crystal molecules, the second cholesteric liquid crystal molecules 231 are red cholesteric liquid crystal molecules, the second dye liquid crystal molecules 232 are red dye liquid crystal molecules, the second color resist layer 113a is blue resist, and the third color resist layer 113b is green resist; or, the first cholesteric liquid crystal molecules 131 are purple cholesteric liquid crystal molecules, the second cholesteric liquid crystal molecules 231 are green cholesteric liquid crystal molecules, the second dye liquid crystal molecules 232 are green dye liquid crystal molecules, the second color resist layer 113a is red resist, and the third color resist layer 113b is blue resist; or, the first cholesteric liquid crystal molecules 131 are purple cholesteric liquid crystal molecules, the second cholesteric liquid crystal molecules 231 are green cholesteric liquid crystal molecules , the second dye liquid crystal molecules 232 are green dye liquid crystal molecules, the second color resist layer 113a is blue resist, and the third color resist layer 113b is red resist; or, the first cholesteric liquid crystal molecules 131 are yellow cholesteric liquid crystal molecules, the second cholesteric liquid crystal molecules 231 are blue cholesteric liquid crystal molecules, the second dye liquid crystal molecules 232 are blue dye liquid crystal molecules, the second color resist layer 113a is red resist, and the third color resist layer 113b is green resist; or, the first cholesteric liquid crystal molecules 131 are yellow cholesteric liquid crystal molecules, the second cholesteric liquid crystal molecules 231 are blue cholesteric liquid crystal molecules, the second dye liquid crystal molecules 232 are blue dye liquid crystal molecules, the second color resist layer 113a is green resist, and the third color resist layer 113b is red resist. No limitation is made here.

[0074] Further, the reflective display device includes a light absorbing layer 30 disposed on the entire surface, and the light absorbing layer 30 is disposed on the side of the second liquid crystal cell 20 away from the first liquid crystal cell 10 and is used to absorb light passing through the first liquid crystal cell 10 and the second liquid crystal cell 20, so that the reflective display device is darker in the black state to improve the contrast. Optionally, the light absorbing layer 30 uses black ink, and the L value (representing brightness) of the black ink is greater than 25 and the OD value (optical density) is greater than 4, so that the light absorbing layer 30 has the characteristics of high blackness and good glossiness, ensuring that the black screen is darker. 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 that covers the entire surface of the second array substrate 22, and the light absorbing layer 30 covers the side of the second array substrate 22 away from the second liquid crystal layer 23.

[0075] Furthermore, a black matrix 112 is provided on the color filter substrate 11 . The black matrix 112 is used to separate the plurality of pixel units P from each other, thereby avoiding the problem of color mixing between adjacent pixel units P.

[0076] The color filter substrate 11, the first array substrate 12, the counter substrate 21 and the second array substrate 22 can be made of transparent substrates such as glass, acrylic and polycarbonate. The materials of 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).

[0077] The present application also provides a driving method of a reflective display device, which is used to drive the reflective display device as described above. The driving method comprises:

[0078] When the first color pixel unit P1 is in a bright state, the first cholesteric liquid crystal molecules 131 in the area corresponding to the first color pixel unit P1 are controlled to be in a vertical standing posture or in a disordered tilted state, so that the first cholesteric liquid crystal molecules 131 in the area corresponding to the first color pixel unit P1 are in a transparent state or a foggy state, and light can pass through the first liquid crystal layer 13; and the second cholesteric liquid crystal molecules 231 in the area corresponding to the first color pixel unit P1 are controlled to be in a lying posture, so that the second cholesteric liquid crystal molecules 231 in the area corresponding to the first color pixel unit P1 are in a reflective state. At this time, the second liquid crystal layer 23 in the area corresponding to the first color pixel unit P1 reflects the first color light (red light), and the second dye liquid crystal molecules 232 can filter the reflected first color light, so that the color of the reflected light is purer. When the first color pixel unit P1 is in a dark state, the first cholesteric liquid crystal molecules 131 and the second cholesteric liquid crystal molecules 231 in the area corresponding to the first color pixel unit P1 are controlled to be in a vertical standing posture or in a disordered tilted state, so that the first cholesteric liquid crystal molecules 131 and the second cholesteric liquid crystal molecules 231 in the area corresponding to the first color pixel unit P1 are in a transparent state or a foggy state. At this time, light directly passes through the first liquid crystal layer 13 and the second liquid crystal layer 23, and is absorbed by the light absorption layer 30, appearing black or foggy black.

[0079] When the second color pixel unit P2 is in the bright state, the first cholesteric liquid crystal molecules 131 in the area corresponding to the second color pixel unit P2 are controlled to be in a lying posture, so that the first cholesteric liquid crystal molecules 131 in the area corresponding to the second color pixel unit P2 are all in a reflective state. Since the filtering wavelength of the second color color resist layer 113a partially overlaps with the wavelength of the complementary color light (i.e., the light reflected by the first liquid crystal layer 13 in the reflective state), at this time, the first liquid crystal layer 13 in the area corresponding to the second color pixel unit P2 can reflect part of the second color light (green light); and the second cholesteric liquid crystal molecules 231 in the area corresponding to the second color pixel unit P2 are controlled to be in a transparent state, a foggy state or a reflective state. Since the second liquid crystal layer 23 cannot reflect the second color light, the second cholesteric liquid crystal molecules 231 can be in any state. When the second color pixel unit P2 is in the dark state, the first cholesteric liquid crystal molecules 131 in the area corresponding to the second color pixel unit P2 are controlled to be in a vertical standing posture or in a disordered tilted state, so that the first cholesteric liquid crystal molecules 131 in the area corresponding to the second color pixel unit P2 are in a transparent state or a foggy state; and the second cholesteric liquid crystal molecules 231 in the area corresponding to the second color pixel unit P2 are controlled to be in a light-transmitting state, a foggy state or a reflective state. Since the second liquid crystal layer 23 cannot reflect the second color light, the second cholesteric liquid crystal molecules 231 can be in any state. At this time, the light directly passes through the first liquid crystal layer 13 and the second liquid crystal layer 23, and is absorbed by the light absorption layer 30, showing black or foggy black. Of course, when the second cholesteric liquid crystal molecules 231 are in a reflective state or a foggy state, part of the second color light will also be absorbed by the second dye liquid crystal molecules 232 to enhance the black state effect.

[0080] When the third color pixel unit P3 is in the bright state, the first cholesteric liquid crystal molecules 131 in the area corresponding to the third color pixel unit P3 are controlled to be in a lying posture, so that the first cholesteric liquid crystal molecules 131 in the area corresponding to the third color pixel unit P3 are all in a reflective state. Since the filtering wavelength of the third color color resist layer 113b partially overlaps with the wavelength of the complementary color light (i.e., the light reflected by the first liquid crystal layer 13 in the reflective state), at this time, the first liquid crystal layer 13 in the area corresponding to the third color pixel unit P3 can reflect part of the third color light (blue light); and the second cholesteric liquid crystal molecules 231 in the area corresponding to the third color pixel unit P3 are controlled to be in a transparent state, a foggy state or a reflective state. Since the second liquid crystal layer 23 cannot reflect the second color light, the second cholesteric liquid crystal molecules 231 can be in any state. When the third color pixel unit P3 is in the dark state, the first cholesteric liquid crystal molecules 131 in the area corresponding to the third color pixel unit P3 are controlled to be in a vertical standing posture or in a disordered tilted state, so that the first cholesteric liquid crystal molecules 131 in the area corresponding to the third color pixel unit P3 are in a transparent state or a foggy state; and the second cholesteric liquid crystal molecules 231 in the area corresponding to the third color pixel unit P3 are controlled to be in a light-transmitting state, a foggy state or a reflective state. Since the second liquid crystal layer 23 cannot reflect the third color light, the second cholesteric liquid crystal molecules 231 can be in any state. At this time, the light directly passes through the first liquid crystal layer 13 and the second liquid crystal layer 23, and is absorbed by the light absorption layer 30, showing black or foggy black. Of course, when the second cholesteric liquid crystal molecules 231 are in a reflective state or a foggy state, part of the third color light will also be absorbed by the second dye liquid crystal molecules 232 to enhance the black state effect.

[0081] Table 1 below is a state analysis table of the first cholesteric liquid crystal molecules 131 and the second cholesteric liquid crystal molecules 231 corresponding to the first color pixel unit P1 , the second color pixel unit P2 , and the third color pixel unit P3 in the bright / dark state:

[0082]

[0083] Figure 8 This is one of the structural schematic diagrams of the reflective display device in the first embodiment of the present invention when displaying a pure red picture. Fig. 9 This is the second structural schematic diagram of the reflective display device in the first embodiment of the present invention when displaying a pure red image. Fig.10 This is the third structural diagram of the reflective display device in the first embodiment of the present invention when displaying a pure red image. Figures 8 to 10 As shown, when the reflective display device displays the first color, all first color pixel units P1 are controlled to be in a bright state and reflect the first color light (red light), and all second color pixel units P2 and third color pixel units P3 are controlled to be in a dark state.

[0084] Fig.11 This is one of the structural schematic diagrams of the reflective display device in the first embodiment of the present invention when displaying a pure green picture. Fig.12 This is the second structural schematic diagram of the reflective display device in the first embodiment of the present invention when displaying a pure green picture. Fig.13 This is the third structural diagram of the reflective display device in the first embodiment of the present invention when displaying a pure green picture. Figures 11 to 13 As shown, when the reflective display device displays the second color, all first color pixel units P1 and third color pixel units P3 are controlled to be in a dark state, and all second color pixel units P2 are controlled to be in a bright state and reflect the second color light (green light).

[0085] Fig.14 This is one of the structural schematic diagrams of the reflective display device in the first embodiment of the present invention when displaying a pure blue picture. Fig.15 This is the second structural schematic diagram of the reflective display device in the first embodiment of the present invention when displaying a pure blue picture. Fig.16 This is the third structural diagram of the reflective display device in the first embodiment of the present invention when displaying a pure blue picture. Figures 14 to 16 As shown, when the reflective display device displays the third color, all first color pixel units P1 and second color pixel units P2 are controlled to be in a dark state, and all third color pixel units P3 are controlled to be in a bright state and reflect the third color light (blue light).

[0086] Fig.17 This is one of the structural schematic diagrams of the reflective display device in the first embodiment of the present invention when displaying a pure black picture. Fig.18 This is the second structural schematic diagram of the reflective display device in the first embodiment of the present invention when displaying a pure black picture. Fig.19 This is a third structural diagram of the reflective display device in the first embodiment of the present invention when displaying a pure black screen. Figures 17 to 19 As shown, when the reflective display device displays a pure black image, all the first color pixel units P1 , the second color pixel units P2 , and the third color pixel units P3 are controlled to be in a dark state.

[0087] Fig. 20 This is one of the structural schematic diagrams of the reflective display device in the first embodiment of the present invention when displaying a color picture. Fig.21 This is the second structural schematic diagram of the reflective display device in the first embodiment of the present invention when displaying a color picture. Fig. 22 This is a third structural diagram of the reflective display device in the first embodiment of the present invention when displaying a color image. Figure 20 to Figure 22As shown, when the reflective display device displays a color image, all the first color pixel units P1, the second color pixel units P2 and the third color pixel units P3 are controlled to display corresponding brightness respectively, and various colors of light are formed through the principle of mutual mixing of red, green and blue light, thereby realizing color display.

[0088] [Example 2]

[0089] Fig.23 Schematic diagram of the structure of the reflective display device in the initial state in the second embodiment of the present invention. Fig.23 As shown, the reflective display device and driving method provided in the second embodiment of the present invention are similar to those in the first embodiment ( Figures 2 to 22 ) are basically the same, except that:

[0090] In this embodiment, the first liquid crystal layer 13 includes first dye liquid crystal molecules 132 that are mixed with the first cholesteric liquid crystal molecules 131. The first dye liquid crystal molecules 132 are the same color as the first cholesteric liquid crystal molecules 131 and rotate synchronously with the first cholesteric liquid crystal molecules 131. The first dye liquid crystal molecules 132 use positive dye liquid crystal molecules. The light absorption capacity of the long axis of the positive dye liquid crystal molecules is greater than the light absorption capacity of the short axis. The positive dye liquid crystal molecules have the characteristics of strong light absorption capacity of the long axis and weak light absorption capacity of the short axis. The long axis absorbs part of the light, thereby presenting a color corresponding to the first dye liquid crystal molecules 132. For example, the first dye liquid crystal molecules 132 use purple dye liquid crystal molecules, and the long axis of the purple dye liquid crystal molecules can absorb the green band and present purple; similarly, if it is a red dye liquid crystal molecule, the long axis of the red dye liquid crystal molecule can absorb the cyan band and present red. Of course, the first dye liquid crystal molecules 132 can also use other single-color dye liquid crystal molecules, such as blue, green, yellow, etc.

[0091] Further, the first cholesteric liquid crystal molecules 131 reflect the first color light in the reflection state, and the second cholesteric liquid crystal molecules 231 reflect the fourth color light in the reflection state, and the first color and the fourth color are complementary colors. The first color, the second color, and the third color are each one of red, green, and blue. In this embodiment, the first cholesteric liquid crystal molecules 131 are red cholesteric liquid crystal molecules, the first dye liquid crystal molecules 132 are red dye liquid crystal molecules, the second cholesteric liquid crystal molecules 231 are cyan cholesteric liquid crystal molecules, the second color color resist layer 113a is green color resist, and the third color color resist layer 113b is blue color resist. Of course, in other embodiments, the first cholesteric liquid crystal molecules 131 are red cholesteric liquid crystal molecules, the first dye liquid crystal molecules 132 are red dye liquid crystal molecules, the second cholesteric liquid crystal molecules 231 are cyan cholesteric liquid crystal molecules, the second color resist layer 113a is a blue resist, and the third color resist layer 113b is a green resist; or, the first cholesteric liquid crystal molecules 131 are green cholesteric liquid crystal molecules, the first dye liquid crystal molecules 132 are green dye liquid crystal molecules, the second cholesteric liquid crystal molecules 231 are purple cholesteric liquid crystal molecules, the second color resist layer 113a is a red resist, and the third color resist layer 113b is a blue resist; or, the first cholesteric liquid crystal molecules 131 are green cholesteric liquid crystal molecules, the first dye liquid crystal molecules 132 are green dye liquid crystal molecules, the second cholesteric liquid crystal molecules 231 are purple cholesteric liquid crystal molecules, the second color resist layer 113a is a red resist, and the third color resist layer 113b is a blue resist; The second cholesteric liquid crystal molecules 231 are purple cholesteric liquid crystal molecules, the second color resist layer 113a is a blue color resist, and the third color resist layer 113b is a red color resist; or, the first cholesteric liquid crystal molecules 131 are blue cholesteric liquid crystal molecules, the first dye liquid crystal molecules 132 are blue dye liquid crystal molecules, the second cholesteric liquid crystal molecules 231 are yellow cholesteric liquid crystal molecules, the second color resist layer 113a is a red color resist, and the third color resist layer 113b is a green color resist; or, the first cholesteric liquid crystal molecules 131 are blue cholesteric liquid crystal molecules, the first dye liquid crystal molecules 132 are blue dye liquid crystal molecules, the second cholesteric liquid crystal molecules 231 are yellow cholesteric liquid crystal molecules, the second color resist layer 113a is a green color resist, and the third color resist layer 113b is a red color resist. This is not limited here.

[0092] The present application also provides a driving method of a reflective display device, which is used to drive the reflective display device as described above. The driving method comprises:

[0093] When the first color pixel unit P1 is in a bright state, the first cholesteric liquid crystal molecules 131 in the area corresponding to the first color pixel unit P1 are controlled to be in a lying posture, so that the first cholesteric liquid crystal molecules 131 in the area corresponding to the first color pixel unit P1 are in a reflective state. At this time, the first cholesteric liquid crystal molecules 131 in the area corresponding to the first color pixel unit P1 reflect the first color light (red light), and the first dye liquid crystal molecules 132 can filter the reflected first color light, so that the color of the reflected light is purer; and the second cholesteric liquid crystal molecules 231 in the area corresponding to the first color pixel unit P1 are controlled to be in a vertical standing posture or in a disordered tilted state, so that the second cholesteric liquid crystal molecules 231 in the area corresponding to the first color pixel unit P1 are in a transparent state or a foggy state, and the remaining light can pass through the second liquid crystal layer 23. When the first color pixel unit P1 is in a dark state, the first cholesteric liquid crystal molecules 131 and the second cholesteric liquid crystal molecules 231 in the area corresponding to the first color pixel unit P1 are controlled to be in a vertical standing posture or in a disordered tilted state, so that the first cholesteric liquid crystal molecules 131 and the second cholesteric liquid crystal molecules 231 in the area corresponding to the first color pixel unit P1 are in a transparent state or a foggy state. At this time, light directly passes through the first liquid crystal layer 13 and the second liquid crystal layer 23, and is absorbed by the light absorption layer 30, appearing black or foggy black.

[0094] When the second color pixel unit P2 is in the bright state, the second cholesteric liquid crystal molecules 231 in the area corresponding to the second color pixel unit P2 are controlled to be in a flat position, so that the second cholesteric liquid crystal molecules 231 in the area corresponding to the second color pixel unit P2 are in a reflective state. Since the filtering wavelength of the second color color resist layer 113a partially overlaps with the wavelength of the complementary color light (i.e., the light reflected by the second liquid crystal layer 23 in the reflective state), at this time, the second liquid crystal layer 23 in the area corresponding to the second color pixel unit P2 can reflect part of the second color light (green light); and The first cholesteric liquid crystal molecules 131 in the area corresponding to the second color pixel unit P2 are all in a transparent state, a foggy state or a reflective state. Since the first liquid crystal layer 13 cannot reflect the second color light, the first cholesteric liquid crystal molecules 131 can be in any state. However, when the first cholesteric liquid crystal molecules 131 are in a reflective state or a foggy state, part of the second color light will also be absorbed by the first dye liquid crystal molecules 132, resulting in a decrease in the utilization rate of the light by the second color pixel unit P2. Therefore, the first cholesteric liquid crystal molecules 131 in the area corresponding to the second color pixel unit P2 are preferably in a transparent state. When the second color pixel unit P2 is in the dark state, the second cholesteric liquid crystal molecules 231 in the area corresponding to the second color pixel unit P2 are controlled to be in a vertical standing posture or in a disordered tilted state, so that the second cholesteric liquid crystal molecules 231 in the area corresponding to the second color pixel unit P2 are in a transparent state or a foggy state; and the first cholesteric liquid crystal molecules 131 in the area corresponding to the second color pixel unit P2 are controlled to be in a light-transmitting state, a foggy state or a reflective state. Since the first liquid crystal layer 13 cannot reflect the second color light, the first cholesteric liquid crystal molecules 131 can be in any state. At this time, the light directly passes through the first liquid crystal layer 13 and the second liquid crystal layer 23, and is absorbed by the light absorption layer 30, showing black or foggy black. Of course, when the first cholesteric liquid crystal molecules 131 are in a reflective state or a foggy state, part of the second color light will also be absorbed by the first dye liquid crystal molecules 132 to enhance the black state effect.

[0095] When the third color pixel unit P3 is in a bright state, the second cholesteric liquid crystal molecules 231 in the area corresponding to the third color pixel unit P3 are controlled to be in a flat position, so that the second cholesteric liquid crystal molecules 231 in the area corresponding to the third color pixel unit P3 are in a reflective state. Since the filtering wavelength of the third color color resist layer 113b partially overlaps with the wavelength of the complementary color light (i.e., the light reflected by the second liquid crystal layer 23 in the reflective state), at this time, the second liquid crystal layer 23 in the area corresponding to the third color pixel unit P3 can reflect part of the third color light (blue light); and The first cholesteric liquid crystal molecules 131 in the area corresponding to the third color pixel unit P3 are all in a transparent state, a foggy state or a reflective state. Since the first liquid crystal layer 13 cannot reflect the third color light, the first cholesteric liquid crystal molecules 131 can be in any state. However, when the first cholesteric liquid crystal molecules 131 are in a reflective state or a foggy state, part of the third color light will also be absorbed by the first dye liquid crystal molecules 132, resulting in a decrease in the utilization rate of the light by the third color pixel unit P3. Therefore, the first cholesteric liquid crystal molecules 131 in the area corresponding to the third color pixel unit P3 are preferably in a transparent state. When the third color pixel unit P3 is in the dark state, the second cholesteric liquid crystal molecules 231 in the area corresponding to the third color pixel unit P3 are controlled to be in a vertical standing posture or in a disordered tilted state, so that the second cholesteric liquid crystal molecules 231 in the area corresponding to the third color pixel unit P3 are in a transparent state or a foggy state; and the first cholesteric liquid crystal molecules 131 in the area corresponding to the third color pixel unit P3 are controlled to be in a light-transmitting state, a foggy state or a reflective state. Since the first liquid crystal layer 13 cannot reflect the third color light, the first cholesteric liquid crystal molecules 131 can be in any state. At this time, the light directly passes through the first liquid crystal layer 13 and the second liquid crystal layer 23, and is absorbed by the light absorption layer 30, showing black or foggy black. Of course, when the first cholesteric liquid crystal molecules 131 are in a reflective state or a foggy state, part of the third color light will also be absorbed by the first dye liquid crystal molecules 132 to enhance the black state effect.

[0096] Table 2 below is a state analysis table of the first cholesteric liquid crystal molecules 131 and the second cholesteric liquid crystal molecules 231 corresponding to the first color pixel unit P1 , the second color pixel unit P2 and the third color pixel unit P3 in the bright / dark state:

[0097]

[0098] Please refer to Table 2 above:

[0099] When the reflective display device displays the first color, all first color pixel units P1 are controlled to be in a bright state and reflect the first color light (red light), and all second color pixel units P2 and third color pixel units P3 are controlled to be in a dark state.

[0100] When the reflective display device displays the second color, all the first color pixel units P1 and the third color pixel units P3 are controlled to be in a dark state, and all the second color pixel units P2 are controlled to be in a bright state and reflect the second color light (green light).

[0101] When the reflective display device displays the third color, all first color pixel units P1 and second color pixel units P2 are controlled to be in a dark state, and all third color pixel units P3 are controlled to be in a bright state and reflect the third color light (blue light).

[0102] When the reflective display device displays a pure black image, all the first color pixel units P1 , the second color pixel units P2 , and the third color pixel units P3 are controlled to be in a dark state.

[0103] When the reflective display device displays a color image, all the first color pixel units P1, the second color pixel units P2 and the third color pixel units P3 are controlled to display corresponding brightness respectively, and various colors of light are formed through the principle of mutual mixing of red, green and blue light, thereby realizing color display.

[0104] It should be understood by those skilled in the art that the rest of the structure and working principle of this embodiment are the same as those of the first embodiment and will not be described in detail here.

[0105] [Example 3]

[0106] The reflective display device and driving method provided in the third embodiment of the present invention are similar to those in the first embodiment ( Figures 2 to 22 )、Example 2 ( Fig.23 ) are basically the same, except that:

[0107] Fig.24 FIG. 1 is one of the structural schematic diagrams of the reflective display device in the initial state in the third embodiment of the present invention. Fig.24As shown, in one embodiment, the first liquid crystal layer 13 includes first dye liquid crystal molecules 132 mixed with the first cholesteric liquid crystal molecules 131, and the first dye liquid crystal molecules 132 and the first cholesteric liquid crystal molecules 131 are of the same color and rotate synchronously with the first cholesteric liquid crystal molecules 131. At the same time, the second liquid crystal layer 23 also includes second dye liquid crystal molecules 232 mixed with the second cholesteric liquid crystal molecules 231, and the second dye liquid crystal molecules 232 and the second cholesteric liquid crystal molecules 231 are of the same color and rotate synchronously with the second cholesteric liquid crystal molecules 231. The first dye liquid crystal molecules 132 can filter the light reflected by the first cholesteric liquid crystal molecules 131, so that the color of the light reflected by the first cholesteric liquid crystal molecules 131 is purer. The second dye liquid crystal molecules 232 can filter the light reflected by the second cholesteric liquid crystal molecules 231, so that the color of the light reflected by the second cholesteric liquid crystal molecules 231 is purer.

[0108] Fig.25 FIG. 2 is a second structural diagram of the reflective display device in the initial state in the third embodiment of the present invention. Fig.25 As shown, in one embodiment, the first cholesteric liquid crystal molecules 131 are yellow cholesteric liquid crystal molecules, the first dye liquid crystal molecules 132 are yellow dye liquid crystal molecules, the second cholesteric liquid crystal molecules 231 are blue cholesteric liquid crystal molecules, the second dye liquid crystal molecules 232 are blue dye liquid crystal molecules, the second color resist layer 113a is red resist, and the third color resist layer 113b is green resist.

[0109] Fig.26 FIG. 3 is a third structural diagram of the reflective display device in the initial state in the third embodiment of the present invention. Fig.26 As shown, in one embodiment, the first cholesteric liquid crystal molecules 131 are purple cholesteric liquid crystal molecules, the first dye liquid crystal molecules 132 are purple dye liquid crystal molecules, the second cholesteric liquid crystal molecules 231 are green cholesteric liquid crystal molecules, the second dye liquid crystal molecules 232 are green dye liquid crystal molecules, the second color resist layer 113a is a blue color resist, and the third color resist layer 113b is a red color resist.

[0110] It should be understood by those skilled in the art that the rest of the structure and working principle of this embodiment are the same as those of Embodiment 1 and Embodiment 2, and will not be described in detail here.

[0111] In this document, the directional words such as up, down, left, right, front, and back are defined by the positions of the structures in the drawings and the positions of the structures relative to each other, just for the sake of clarity and convenience in expressing the technical solution. It should be understood that the use of the directional words should not limit the scope of protection claimed in this application. It should also be understood that the terms "first" and "second" used in this document are only used to distinguish names and are not used to limit quantity and order.

[0112] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to the technical contents disclosed above without departing from the scope of the technical solution of the present invention, which are equivalent embodiments of equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A reflective display device, characterized in that: The reflective display device comprises a first liquid crystal box (10) and a second liquid crystal box (20) stacked on the light incident side of the first liquid crystal box (10), wherein the reflective display device comprises a plurality of pixel units (P) distributed in an array, wherein the plurality of pixel units (P) comprise a first color pixel unit (P1), a second color pixel unit (P2) and a third color pixel unit (P3); The first liquid crystal box (10) comprises a color film substrate (11), a first array substrate (12) arranged opposite to the color film substrate (11), and a first liquid crystal layer (13) located between the color film substrate (11) and the first array substrate (12); the color film substrate (11) is located on a side of the first liquid crystal box (10) away from the second liquid crystal box (20); the first liquid crystal layer (13) comprises first cholesteric liquid crystal molecules (131); the first cholesteric liquid crystal molecules (131) all reflect light of the same color in a reflection state. The color film substrate (11) is transparent in an area corresponding to the first color pixel unit (P1), a second color resist layer (113a) is provided in an area corresponding to the second color pixel unit (P2), and a third color resist layer (113b) is provided in an area corresponding to the third color pixel unit (P3); a first pixel electrode (121) corresponding to the pixel unit (P) is provided on the first array substrate (12); and a first common electrode (111) matched with the first pixel electrode (121) is provided on the color film substrate (11); The second liquid crystal box (20) comprises an opposing substrate (21), a second array substrate (22) arranged opposite to the opposing substrate (21), and a second liquid crystal layer (23) located between the opposing substrate (21) and the second array substrate (22); the second liquid crystal layer (23) comprises second cholesteric liquid crystal molecules (231); the second cholesteric liquid crystal molecules (231) all reflect light of the same color in a reflective state; a second pixel electrode (221) corresponding to the pixel unit (P) is provided on the second array substrate (22); and a second common electrode (211) matched with the second pixel electrode (212) is provided on the opposing substrate (21); One of the first cholesteric liquid crystal molecules (131) and the second cholesteric liquid crystal molecules (231) reflects a first color light in a reflective state, and the other reflects a complementary color light of the first color light in a reflective state, and the filtering wavelength of the second color color resist layer (113a) and the filtering wavelength of the third color 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: The first liquid crystal layer (13) comprises first dye liquid crystal molecules (132) that are mixed with the first cholesteric liquid crystal molecules (131); the first dye liquid crystal molecules (132) and the first cholesteric liquid crystal molecules (131) are of the same color and rotate synchronously with the first cholesteric liquid crystal molecules (131).

3. The reflective display device according to claim 1 or 2, characterized in that: The second liquid crystal layer (23) comprises second dye liquid crystal molecules (232) that are mixed with the second cholesteric liquid crystal molecules (231); the second dye liquid crystal molecules (232) are of the same color as the second cholesteric liquid crystal molecules (231) and rotate synchronously with the second cholesteric liquid crystal molecules (231).

4. The reflective display device according to claim 1, characterized in that: The first color, the second color, and the third color are each one of red, green, and blue.

5. The reflective display device according to claim 1, characterized in that: The first cholesteric liquid crystal molecules (131) reflect light of the first color in the reflective state, and the second cholesteric liquid crystal molecules (231) reflect light of the fourth color in the reflective state; or the first cholesteric liquid crystal molecules (131) reflect light of the fourth color in the reflective state, and the second cholesteric liquid crystal molecules (231) reflect light of the first color in the reflective state; The first color and the fourth color are complementary colors.

6. The reflective display device according to claim 1, wherein: The reflective display device comprises a light absorbing layer (30) disposed on the entire surface. The light absorbing layer (30) is disposed on a side of the second liquid crystal box (20) away from the first liquid crystal box (10) and is used to absorb light passing through the first liquid crystal box (10) and the second liquid crystal box (20).

7. The reflective display device according to claim 1, wherein: A black matrix (112) is provided on the color film substrate (11), and the black matrix (112) is used to separate the plurality of pixel units (P) from each other.

8. A method for driving a reflective display device, characterized in that: Used to drive the reflective display device according to any one of claims 1 to 7, the first cholesteric liquid crystal molecules (131) reflect fourth color light in the reflective state, the second cholesteric liquid crystal molecules (231) reflect first color light in the reflective state, the first color and the fourth color are complementary colors, and the driving method comprises: When the first color pixel unit (P1) is in a bright state, the second cholesteric liquid crystal molecules (231) in the area corresponding to the first color pixel unit (P1) are controlled to be in a reflective state, and the first cholesteric liquid crystal molecules (131) in the area corresponding to the first color pixel unit (P1) are controlled to be in a transparent state or a foggy state. At this time, the second liquid crystal layer (23) in the area corresponding to the first color pixel unit (P1) reflects the first color light. When the first color pixel unit (P1) is in a dark state, the first cholesteric liquid crystal molecules (131) and the second cholesteric liquid crystal molecules (231) in the area corresponding to the first color pixel unit (P1) are controlled to be in a transparent state or a foggy state. At this time, the light directly passes through the first liquid crystal layer (13) and the second liquid crystal layer (23); When the second color pixel unit (P2) is in a bright state, the first cholesteric liquid crystal molecules (131) in the area corresponding to the second color pixel unit (P2) are controlled to be in a reflective state, and the second cholesteric liquid crystal molecules (231) in the area corresponding to the second color pixel unit (P2) are controlled to be in a transparent state, a foggy state or a reflective state. At this time, the first liquid crystal layer (13) in the area corresponding to the second color pixel unit (P2) reflects the second color light. When the second color pixel unit (P2) is in a dark state, the first cholesteric liquid crystal molecules (131) in the area corresponding to the second color pixel unit (P2) are controlled to be in a transparent state or a foggy state, and the second cholesteric liquid crystal molecules (231) in the area corresponding to the second color pixel unit (P2) are controlled to be in a light-transmitting state, a foggy state or a reflective state. At this time, the light directly passes through the first liquid crystal layer (13) and the second liquid crystal layer (23); When the third color pixel unit (P3) is in a bright state, the first cholesteric liquid crystal molecules (131) in the area corresponding to the third color pixel unit (P3) are controlled to be in a reflective state, and the second cholesteric liquid crystal molecules (231) in the area corresponding to the third color pixel unit (P3) are controlled to be in a transparent state, a foggy state or a reflective state. At this time, the first liquid crystal layer (13) in the area corresponding to the third color pixel unit (P3) reflects the third color light. When the third color pixel unit (P3) is in a dark state, the first cholesteric liquid crystal molecules (131) in the area corresponding to the third color pixel unit (P3) are controlled to be in a transparent state or a foggy state, and the second cholesteric liquid crystal molecules (231) in the area corresponding to the third color pixel unit (P3) are controlled to be in a light-transmitting state, a foggy state or a reflective state. At this time, the light directly passes through the first liquid crystal layer (13) and the second liquid crystal layer (23).

9. A method for driving a reflective display device, characterized in that: Used to drive the reflective display device according to any one of claims 1 to 7, the first cholesteric liquid crystal molecules (131) reflect a first color light in a reflective state, the second cholesteric liquid crystal molecules (231) reflect a fourth color light in a reflective state, the first color and the fourth color are complementary colors, and the driving method comprises: When the first color pixel unit (P1) is in a bright state, the first cholesteric liquid crystal molecules (131) in the area corresponding to the first color pixel unit (P1) are controlled to be in a reflective state, and the second cholesteric liquid crystal molecules (231) in the area corresponding to the first color pixel unit (P1) are controlled to be in a transparent state or a foggy state. At this time, the first liquid crystal layer (13) in the area corresponding to the first color pixel unit (P1) reflects the first color light. When the first color pixel unit (P1) is in a dark state, the first cholesteric liquid crystal molecules (131) and the second cholesteric liquid crystal molecules (231) in the area corresponding to the first color pixel unit (P1) are controlled to be in a transparent state or a foggy state. At this time, the light directly passes through the first liquid crystal layer (13) and the second liquid crystal layer (23); When the second color pixel unit (P2) is in a bright state, the second cholesteric liquid crystal molecules (231) in the area corresponding to the second color pixel unit (P2) are controlled to be in a reflective state, and the first cholesteric liquid crystal molecules (131) in the area corresponding to the second color pixel unit (P2) are controlled to be in a transparent state, a foggy state or a reflective state. At this time, the second liquid crystal layer (23) in the area corresponding to the second color pixel unit (P2) reflects the second color light. When the second color pixel unit (P2) is in a dark state, the second cholesteric liquid crystal molecules (231) in the area corresponding to the second color pixel unit (P2) are controlled to be in a transparent state or a foggy state, and the first cholesteric liquid crystal molecules (131) in the area corresponding to the second color pixel unit (P2) are controlled to be in a light-transmitting state, a foggy state or a reflective state. At this time, the light directly passes through the first liquid crystal layer (13) and the second liquid crystal layer (23); When the third color pixel unit (P3) is in a bright state, the second cholesteric liquid crystal molecules (231) in the area corresponding to the third color pixel unit (P3) are controlled to be in a reflective state, and the first cholesteric liquid crystal molecules (131) in the area corresponding to the third color pixel unit (P3) are controlled to be in a transparent state, a foggy state or a reflective state. At this time, the second liquid crystal layer (23) in the area corresponding to the third color pixel unit (P3) reflects the third color light. When the third color pixel unit (P3) is in a dark state, the second cholesteric liquid crystal molecules (231) in the area corresponding to the third color pixel unit (P3) are controlled to be in a transparent state or a foggy state, and the first cholesteric liquid crystal molecules (131) in the area corresponding to the third color pixel unit (P3) are controlled to be in a light-transmitting state, a foggy state or a reflective state. At this time, the light directly passes through the first liquid crystal layer (13) and the second liquid crystal layer (23).

10. The driving method of the reflective display device according to claim 8 or 9, characterized in that: The driving method comprises: When the reflective display device displays a first color, all the first color pixel units (P1) are controlled to be in a bright state, and all the second color pixel units (P2) and the third color pixel units (P3) are controlled to be in a dark state; When the reflective display device displays a second color, all of the first color pixel units (P1) and the third color pixel units (P3) are controlled to be in a dark state, and all of the second color pixel units (P2) are controlled to be in a bright state; When the reflective display device displays a third color, all of the first color pixel units (P1) and the second color pixel units (P2) are controlled to be in a dark state, and all of the third color pixel units (P3) are controlled to be in a bright state; When the reflective display device displays a color image, all of the first color pixel units (P1), the second color pixel units (P2) and the third color pixel units (P3) are controlled to display corresponding brightness.

Images