Reflective display device and driving method

Abstract

The invention discloses a reflective display device and a driving method, the reflective display device comprises a bistable liquid crystal box, the bistable liquid crystal box comprises a color film substrate, an array substrate and a liquid crystal layer, and the liquid crystal layer comprises bistable liquid crystal molecules and black dye molecules which are mixed with each other. All the bistable liquid crystal molecules reflect invisible light in a reflection state, a reflective pixel electrode is arranged on the array substrate, and a common electrode is arranged on the color film substrate; the bistable liquid crystal box is provided with a plurality of pixel units distributed in an array mode, a reflective pixel electrode is correspondingly arranged in each pixel unit, and the color film substrate is provided with a color resistance layer in the area corresponding to the pixel units. The black dye molecules and the bistable liquid crystal molecules which reflect invisible light rays in a reflection state are mixed with each other, and the reflective pixel electrode and the color film substrate are matched, so that the reflective display device can realize color reflective display with a better display effect, and is simple in structure, smaller in box thickness and lower in manufacturing cost.

Description

Technical Field

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

[0002] Display panels have the advantages of being thin, light, durable, and energy-saving and environment-friendly with low power consumption. However, they need to be used with a backlight, resulting in a thick module and high cost. 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 liquid crystal displays that require a backlight. Therefore, in an outdoor environment with strong sunlight, the information on the electronic paper can still be clearly seen without the problem of viewing angles. Moreover, due to their advantages such as power saving, high reflectivity, and contrast ratio, electronic paper displays are now widely used in e-readers (such as e-books, e-newspapers) or other electronic components (such as price tags).

[0003] Existing electronic paper displays usually adopt E-Ink microcapsule technology (microcapsule electronic ink technology), SiPix microcup technology (microcup electrophoretic display technology), Bridgestone electronic liquid powder technology, bistable liquid crystal display (Cholesteric Liquid Crystal Display, CLCD) technology, microelectromechanical system (MEMS) technology, or electrowetting technology. However, existing electronic paper display technologies are not as mature as liquid crystal display technologies, with low mass production efficiency, relatively high manufacturing costs, and existing electronic paper displays cannot achieve color display.

[0004] In a reflective display device using bistable liquid crystals in the prior art, due to the requirements of the pitch of bistable liquid crystals, bistable liquid crystals with one pitch can only reflect one color and transmit light of other colors. Therefore, most reflective display devices with a single layer of bistable liquid crystals are displayed in the form of yellow background with black characters or black background with yellow characters, black background with red characters or red background with black characters, etc., and cannot achieve black background with white characters or white background with black characters like a book, which greatly limits the product application; moreover, the color of the light reflected by bistable liquid crystals is poor, affecting the display effect. Figure 1 is a schematic structural diagram of a reflective display device using a three-layer bistable liquid crystal cell in the prior art, as Figure 1 shown. If white display or color display needs to be achieved, the reflective display device needs to use a three-layer bistable liquid crystal cell to reflect red / green / blue light respectively, so as to achieve white display and color display. However, the three-layer bistable liquid crystal cell not only has a relatively large cell thickness but also a high cost. If double-sided reflection display needs to be achieved, the cell thickness of the display device will be even larger, which is not conducive to the development of the display device towards thinness and lightness.

[0005] In the prior art, there are also a small number of display devices that use single-layer bistable liquid crystals to achieve full-color reflective display. Two color resistive layers and a color dye molecule need to cooperate with each other to achieve full-color reflective display. This single-layer bistable liquid crystal reflective display device not only has a complex manufacturing process, but also has a poor full-color reflective display effect. Summary of the Invention

[0006] In order to overcome the disadvantages and deficiencies in the prior art, the purpose of the present invention is to provide a reflective display device and a driving method to solve the problems of complex manufacturing process and poor full-color reflective display effect of the reflective display device in the prior art.

[0007] The purpose of the present invention is achieved through the following technical solutions: The present invention provides a reflective display device, including a bistable liquid crystal cell. The bistable liquid crystal cell includes a color film substrate, an array substrate disposed opposite to the color film substrate, and a liquid crystal layer located between the color film substrate and the array substrate. The liquid crystal layer includes bistable liquid crystal molecules and black dye molecules mixed with the bistable liquid crystal molecules. The black dye molecules rotate synchronously with the bistable liquid crystal molecules. All the bistable liquid crystal molecules reflect non-visible light in the reflective state. A reflective pixel electrode is provided on the array substrate, and a common electrode cooperating with the reflective pixel electrode is provided on the color film substrate; The bistable liquid crystal cell has a plurality of pixel units arranged in an array. Each pixel unit is correspondingly provided with the reflective pixel electrode, and a color resistive layer is provided on the color film substrate in the area corresponding to the pixel unit; When the pixel unit is in the bright state, the bistable liquid crystal molecules in the corresponding area of the pixel unit are all in the transparent state or the fog state; when the pixel unit is in the dark state, the bistable liquid crystal molecules in the corresponding area of the pixel unit are all in the reflective state.

[0008] Further, the bistable liquid crystal molecules are infrared bistable liquid crystal molecules and reflect infrared light in the reflective state; Or, the bistable liquid crystal molecules are ultraviolet bistable liquid crystal molecules and reflect ultraviolet light in the reflective state.

[0009] Further, among the plurality of pixel units, there are green pixel units, blue pixel units, and red pixel units. The color resistive layer includes a green color resistive layer, a blue color resistive layer, and a red color resistive layer. The green color resistive layer corresponds to the green pixel unit, the blue color resistive layer corresponds to the blue pixel unit, and the red color resistive layer corresponds to the red pixel unit.

[0010] Further, a black matrix is provided on the color film substrate, and the black matrix separates the plurality of pixel units from each other.

[0011] Further, the projection of the reflective pixel electrode on the color film substrate partially coincides with the black matrix.

[0012] Further, the reflective display device includes a light-absorbing layer, and the light-absorbing layer is provided on a side of the bistable liquid crystal cell close to the array substrate, and the light-absorbing layer is used for absorbing light passing through the bistable liquid crystal cell.

[0013] Further, the number of the bistable liquid crystal cells is two and they are stacked on each other, and the array substrates of the two bistable liquid crystal cells face each other.

[0014] The present application further provides a driving method for a reflective display device for driving the reflective display device as described above, and the driving method includes: When the pixel unit is in a bright state, controlling all the bistable liquid crystal molecules in the corresponding area of the pixel unit to be in a transparent state or a mist state. At this time, the pixel unit reflects light corresponding to the color of the color resist layer; when the pixel unit is in a dark state, controlling all the bistable liquid crystal molecules in the corresponding area of the pixel unit to be in a reflective state, and ambient light is jointly absorbed by the color resist layer and the black dye molecules.

[0015] Further, among the plurality of pixel units, there are green pixel units, blue pixel units, and red pixel units, the color resist layer includes a green color resist layer, a blue color resist layer, and a red color resist layer, the green color resist layer corresponds to the green pixel unit, the blue color resist layer corresponds to the blue pixel unit, the red color resist layer corresponds to the red pixel unit, and the driving method includes: When the reflective display device displays green, controlling all the green pixel units to be in a bright state, and controlling all the blue pixel units and the red pixel units to be in a dark state; when the reflective display device displays blue, controlling all the blue pixel units to be in a bright state, and controlling all the green pixel units and the red pixel units to be in a dark state; when the reflective display device displays red, controlling all the red pixel units to be in a bright state, and controlling all the green pixel units and the blue pixel units to be in a dark state; when the reflective display device displays white, controlling all the green pixel units, the blue pixel units, and the red pixel units to be in a bright state.

[0016] Further, the driving method includes: When the bistable liquid crystal molecules are switched to the transparent state, a first common voltage is applied to the common electrode, and a first driving voltage is applied to the reflective pixel electrode. The first common voltage and the first driving voltage are always alternating voltages with a first voltage difference and opposite polarities. When the bistable liquid crystal molecules are switched to the fog state, a second common voltage is applied to the common electrode, and a second driving voltage is applied to the reflective pixel electrode. The second common voltage and the second driving voltage are alternating voltages with a first voltage difference and opposite polarities in a first time period, the second common voltage and the second driving voltage are direct currents with no voltage difference in a second time period, the second common voltage and the second driving voltage are alternating voltages with a second voltage difference and opposite polarities in a third time period, and the second common voltage and the second driving voltage are direct currents with no voltage difference in a fourth time period. The second voltage difference is smaller than the first voltage difference. When the bistable liquid crystal molecules are switched to the reflective state, a third common voltage is applied to the common electrode, and a third driving voltage is applied to the reflective pixel electrode. The third common voltage and the third driving voltage are alternating voltages with a first voltage difference and opposite polarities in a first time period, and then, the third common voltage and the third driving voltage are always direct currents with no voltage difference.

[0017] The beneficial effects of the present invention are as follows: By mixing black dye molecules with bistable liquid crystal molecules that can reflect non-visible light in the reflective state, and combining with a reflective pixel electrode and a color filter substrate, a color resist layer is provided on the color filter substrate, and the light is filtered by the color resist layer, so that the reflective display device can achieve a color reflective display with better display effects, and has a simple structure, a smaller cell thickness, and a lower manufacturing cost. Description of the Drawings

[0018] Figure 1 It is a schematic structural diagram of a reflective display device using a three-layer bistable liquid crystal cell in the prior art.

[0019] Figure 2 It is a schematic structural diagram of the reflective display device in the initial state in Embodiment 1 of the present invention.

[0020] Figure 3 It is a schematic structural diagram of the pixel arrangement of the reflective display device in Embodiment 1 of the present invention.

[0021] Figure 4 It is a schematic plan view of the array substrate in Embodiment 1 of the present invention.

[0022] Figure 5 It is a schematic diagram of the principle of the transformation of the three states of the bistable liquid crystal molecules in Embodiment 1 of the present invention.

[0023] Figure 6 It is one of the schematic diagrams of the driving signals for the transformation of the three states of the bistable liquid crystal molecules in the first embodiment of the present invention.

[0024] Figure 7 It is the second schematic diagram of the driving signals for the bistable liquid crystal molecules in the transparent state in the first embodiment of the present invention.

[0025] Figure 8 It is the second schematic diagram of the driving signals for the bistable liquid crystal molecules in the fog state in the first embodiment of the present invention.

[0026] Figure 9 It is the second schematic diagram of the driving signals for the bistable liquid crystal molecules in the reflective state in the first embodiment of the present invention.

[0027] Figure 10 It is one of the schematic diagrams of the structure of the reflective display device in the first embodiment of the present invention when displaying a pure red screen.

[0028] Figure 11 It is the second schematic diagram of the structure of the reflective display device in the first embodiment of the present invention when displaying a pure red screen.

[0029] Figure 12 It is one of the schematic diagrams of the structure of the reflective display device in the first embodiment of the present invention when displaying a pure green screen.

[0030] Figure 13 It is the second schematic diagram of the structure of the reflective display device in the first embodiment of the present invention when displaying a pure green screen.

[0031] Figure 14 It is one of the schematic diagrams of the structure of the reflective display device in the first embodiment of the present invention when displaying a pure blue screen.

[0032] Figure 15 It is the second schematic diagram of the structure of the reflective display device in the first embodiment of the present invention when displaying a pure blue screen.

[0033] Figure 16 It is one of the schematic diagrams of the structure of the reflective display device in the first embodiment of the present invention when displaying a white screen.

[0034] Figure 17 It is the second schematic diagram of the structure of the reflective display device in the first embodiment of the present invention when displaying a white screen.

[0035] Figure 18 It is the schematic diagram of the structure of the reflective display device in the first embodiment of the present invention when displaying a pure black screen.

[0036] Figure 19 It is the schematic diagram of the structure of the reflective display device in the second embodiment of the present invention in the initial state. Detailed implementation mode

[0037] To further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the specific implementation manners, structures, features, and effects of the reflective display device and the driving method proposed according to the present invention are described in detail below with reference to the accompanying drawings and preferred embodiments: [Embodiment 1] Figure 2 FIG. 7 is a schematic structural diagram of the reflective display device in the initial state in Embodiment 1 of the present invention. Figure 3 FIG. 9 is a schematic structural diagram of the pixel arrangement of the reflective display device in Embodiment 1 of the present invention. Figure 4 FIG. 11 is a schematic plan view of the array substrate in Embodiment 1 of the present invention.

[0038] As Figures 2 to 4 shown, a reflective display device provided in Embodiment 1 of the present invention includes a bistable liquid crystal cell 10. The bistable liquid crystal cell 10 includes a color filter substrate 11, an array substrate 12 disposed opposite to the color filter substrate 11, and a liquid crystal layer 13 located between the color filter substrate 11 and the array substrate 12. The liquid crystal layer 13 includes bistable liquid crystal molecules 131 and black dye molecules 132 mixed with the bistable liquid crystal molecules 131. The black dye molecules 132 rotate synchronously with the bistable liquid crystal molecules 131, and all the bistable liquid crystal molecules 131 reflect non-visible light in the reflective state.

[0039] The bistable liquid crystal cell 10 has a plurality of pixel units P arranged in an array. A reflective pixel electrode 121 is provided on the array substrate 12, a common electrode 111 cooperating with the reflective pixel electrode 121 is provided on the color filter substrate 11, and a color resist layer 113 is provided in the area corresponding to each pixel unit P. A reflective pixel electrode 121 and a color resist layer 113 are correspondingly provided in each pixel unit P. The reflective pixel electrode 121 is a block-shaped electrode corresponding to each pixel unit P one by one. A common electrode 111 cooperating with the reflective pixel electrode 121 is provided on the color filter substrate 11, and the common electrode 111 is a planar electrode covering the entire color filter substrate 11. The reflective pixel electrode 121 can not only cooperate with the common electrode 111 to control the deflection of the bistable liquid crystal molecules 131 and the black dye molecules 132 in the liquid crystal layer 13, but also reflect the ambient light irradiated onto the reflective pixel electrode 121. Among them, the reflective pixel electrode 121 is disposed on the side of the array substrate 12 closest to the liquid crystal layer 13, and the common electrode 111 is disposed on the side of the color filter substrate 11 closest to the liquid crystal layer 13, which can not only improve the reflection efficiency but also enhance the response speed of the liquid crystal layer 13.

[0040] When the pixel unit P is in the bright state, both the bistable liquid crystal molecules 131 and the black dye molecules 132 in the corresponding area of the pixel unit P are perpendicular to the color film substrate 11 and the array substrate 12 or both exhibit a disordered tilted state, so that the bistable liquid crystal molecules 131 in the corresponding area of the pixel unit P are all in the transparent state or the fog state. When the pixel unit P is in the dark state, both the bistable liquid crystal molecules 131 and the black dye molecules 132 in the corresponding area of the pixel unit P are in a lying flat posture, so that the bistable liquid crystal molecules 131 in the corresponding area of the pixel unit P are all in the reflective state. Visible light in the ambient light is jointly absorbed by the color filter layer 113 and the black dye molecules 132, while the bistable liquid crystal molecules 131 reflect non-visible light to present black.

[0041] Among them, the bistable liquid crystal molecules 131 have three stable textures: the P state (Planar, planar texture state, reflective state), the FC state (Focal Conic, focal conic state, fog state), and the H state (transparent state). In the P state, the reflection spectrum of the bistable liquid crystal molecules 131 is in the non-visible spectral band, and the bistable liquid crystal molecules 131 reflect non-visible light. The specific light they reflect can be set according to the pitch of the bistable liquid crystal molecules 131, and the reflected wavelength satisfies the condition of λ = n * P (λ is the wavelength, P is the pitch, and n is the refractive index); when in the FC state, the bistable liquid crystal molecules 131 no longer reflect the above light, and the light can be scattered and transmitted through the bistable liquid crystal molecules 131; when in the H state, the bistable liquid crystal molecules 131 also no longer reflect the above light, and the light can be directly transmitted through the bistable liquid crystal molecules 131 without scattering the light. Under the action of a certain electric field, these three states can be converted into each other. The bistable liquid crystal molecules 131 are, for example, cholesteric liquid crystal molecules.

[0042] In this embodiment, the bistable liquid crystal molecules 131 are infrared bistable liquid crystal molecules and reflect infrared light in the reflective state, that is, the main reflection wavelength is above 780 nm. Of course, the bistable liquid crystal molecules 131 can also be ultraviolet bistable liquid crystal molecules and reflect ultraviolet light in the reflective state, that is, the main reflection wavelength is below 380 nm. Thus, the bistable liquid crystal molecules 131 reflect light invisible to the human eye in the reflective state, while visible light is jointly absorbed by the color filter layer 113 and the black dye molecules 132, achieving a better black state effect and improving the contrast.

[0043] The black dye molecule 132 uses a positive dye liquid crystal molecule. The light absorption ability of the long axis of the positive dye liquid crystal molecule is greater than that of the short axis. The positive dye liquid crystal molecule has the characteristic that the light absorption ability of the long axis is strong and the light absorption ability of the short axis is very weak. That is, in this application, the long axis of the black dye molecule 132 can absorb light in the full wavelength range and present black, so as to achieve a better black state effect and improve the contrast. Among them, the concentration of the black dye molecule 132 in the liquid crystal layer 13 is preferably 0.5% - 2%, so that the bistable liquid crystal molecule 131 can present a black state effect in the reflective state, and has little influence on the bistable liquid crystal molecule 131 in the transparent state or fog state, and can still transmit visible light.

[0044] In this embodiment, among the multiple pixel units P, there are a green pixel unit P1, a blue pixel unit P2, and a red pixel unit P3. The color filter layer 113 includes a green color filter layer 113a, a blue color filter layer 113b, and a red color filter layer 113c. The green color filter layer 113a corresponds to the green pixel unit P1, the blue color filter layer 113b corresponds to the blue pixel unit P2, and the red color filter layer 113c corresponds to the red pixel unit P3. Thus, the reflective display device can achieve the display of various colors according to the color mixing principle of red / green / blue three primary colors. Among them, as Figure 3 shown, a column of green pixel units P1, a column of blue pixel units P2, and a column of red pixel units P3 are alternately arranged in the reverse direction in sequence.

[0045] As Figure 4 shown, a plurality of scan lines 101 and a plurality of data lines 102 are provided on the array substrate 12. The plurality of scan lines 101 and the plurality of data lines 102 are insulated and cross-defined to form a plurality of pixel units P. The array substrate 12 is provided with a thin film transistor 103 and a reflective pixel electrode 121 in each pixel unit P. The reflective pixel electrode 121 is electrically connected to the scan line 101 and the data line 102 adjacent to the thin film transistor 103 through the thin film transistor 103. Among them, the thin film transistor 103 includes a gate, an active layer, a drain, and a source. The gate and the scan line 101 are located on the same layer and are electrically connected. The gate and the active layer are separated by an insulating layer. The source is electrically connected to the data line 102, and the drain is electrically connected to the reflective pixel electrode 121 through a contact hole.

[0046] Furthermore, a black matrix 112 is provided on the color filter substrate 11, and the black matrix 112 is used to separate the multiple pixel units P from each other, that is, the black matrix 112 is used to separate the green color resist layer 113a, the blue color resist layer 113b and the red color resist layer 113c from each other on the color filter substrate 11, so as to avoid the problem of color mixing between adjacent pixel units P. The projection of the black matrix 112 on the array substrate 12 corresponds to the scan line 101, the data line 102 and the thin film transistor 103, so that the scan line 101, the data line 102 and the thin film transistor 103 can correspond to each other and play a light effect.

[0047] Furthermore, the projection of the reflective pixel electrode 121 on the color film substrate 11 partially overlaps with the black matrix 112, that is, the width and length of the reflective pixel electrode 121 are both greater than the width and length of the transparent area in the black matrix 112. Optionally, the width of the projection of the reflective pixel electrode 121 on the color film substrate 11 that partially overlaps with the black matrix 112 is less than half the width of the black matrix 112 and is greater than 0, so as to maximize the reflection area and enhance the reflection effect.

[0048] In this embodiment, the reflective display device includes a light absorbing layer 20, which is arranged on the side of the bistable liquid crystal box 10 close to the array substrate 12. The light absorbing layer 20 is used to absorb the light passing through the bistable liquid crystal box 10, so that the reflective display device is darker in the black state, so as to improve the contrast and display quality. Optionally, the light absorbing layer 20 uses black ink, and the L value (representing the 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 20 has the characteristics of high blackness and good glossiness, ensuring that the black screen is darker. Of course, the light absorbing layer 20 can be made of BM material or black opaque glue. In this embodiment, the light absorbing layer 20 is a planar structure that covers the entire surface of the array substrate 12, and the light absorbing layer 20 covers the side of the array substrate 12 away from the liquid crystal layer 13.

[0049] In this embodiment, there are two bistable liquid crystal cells 10 and they are stacked on each other. The array substrates 12 of the two bistable liquid crystal cells 10 are arranged facing each other and share a light absorbing layer 20, so that the reflective display device can achieve double-sided display, and the images displayed on both sides of the two bistable liquid crystal cells 10 will not affect each other, and different images can be displayed independently. The light absorbing layer 20 is arranged between the array substrates 12 of the two bistable liquid crystal cells 10. The light absorbing layer 20 is preferably a black opaque glue, so that it can not only play a bonding role for the two bistable liquid crystal cells 10, but also absorb the light passing through the two bistable liquid crystal cells 10.

[0050] Among them, the color filter substrate 11 and the array substrate 12 can be made of transparent substrates such as glass, acrylic, and polycarbonate. The material of the common electrode 111 can be made of a transparent electrode such as indium tin oxide (ITO) or indium zinc oxide (IZO). The material of the reflective pixel electrode 121 can be made of a metal with a high reflectivity such as aluminum or silver.

[0051] This application also provides a driving method for a reflective display device, which is used to drive the reflective display device as described above. The driving method includes: When the pixel unit P is in the bright state, control the bistable liquid crystal molecules 131 and the black dye molecules 132 in the corresponding area of the pixel unit P to be perpendicular to the color filter substrate 11 and the array substrate 12 or to be in a disordered inclined state, so that the bistable liquid crystal molecules 131 in the corresponding area of the pixel unit P are all in the transparent state or the fog state. At this time, the pixel unit P reflects the light corresponding to the color of the color resist layer 113. When the pixel unit P is in the dark state, control the bistable liquid crystal molecules 131 and the black dye molecules 132 in the corresponding area of the pixel unit P to be in a lying posture, so that the bistable liquid crystal molecules 131 in the corresponding area of the pixel unit P are all in the reflective state. The ambient light is jointly absorbed by the color resist layer 113 and the black dye molecules 132, and the bistable liquid crystal molecules 131 reflect non-visible light to present black.

[0052] In one embodiment, Figure 5 is a schematic diagram of the principle of the transformation of the three states of the bistable liquid crystal in the present invention, Figure 6 is a schematic diagram of the driving signal for the transformation of the three states of the bistable liquid crystal in the present invention. As Figure 5 and Figure 6As shown in the figure, a common voltage Vcom is applied to the common electrode 111, and a first driving voltage V1 is continuously applied to the reflective pixel electrode 121. There is a voltage difference (about 30V) between the common voltage Vcom and the first driving voltage V1. A strong vertical electric field will be formed between the common electrode 111 and the reflective pixel electrode 121, and the bistable liquid crystal molecules 131 will rotate and stop in the H state (transparent state). A common voltage Vcom is applied to the common electrode 111, and a second driving voltage V2 is applied to the reflective pixel electrode 121. There is a voltage difference (for example, 30V) between the second driving voltage V2 and the common voltage Vcom, and the second driving voltage V2 gradually becomes the same as the common voltage Vcom within a first preset time, that is, the second driving voltage V2 first has a large voltage difference from the common voltage Vcom and then slowly decreases and becomes the same as the common voltage Vcom. Therefore, a strong vertical electric field will be formed between the common electrode 111 and the reflective pixel electrode 121 first, and then the vertical electric field slowly disappears, so that the bistable liquid crystal molecules 131 in the bistable liquid crystal molecules 131 rotate and stop in the FC state, which is a scattering state and has a light scattering effect. A common voltage Vcom is applied to the common electrode 111, and a third driving voltage V3 is applied to the reflective pixel electrode 121. There is a voltage difference (for example, 30V) between the third driving voltage V3 and the common voltage Vcom, and the third driving voltage V3 directly becomes the same as the common voltage Vcom at a second preset time, and the second preset time is less than the first preset time, that is, the third driving voltage V3 first has a large voltage difference from the common voltage Vcom and then quickly decreases and becomes the same as the common voltage Vcom. Therefore, a strong vertical electric field will be formed between the common electrode 111 and the reflective pixel electrode 121 first, and then the vertical electric field quickly disappears, so that the bistable liquid crystal molecules 131 rotate and stop in the P state, which is a reflective state. Among them, the common voltage Vcom is a DC common voltage signal of 0V, and the first driving voltage V1, the second driving voltage V2, and the third driving voltage V3 are all AC voltage signals that fluctuate up and down with the DC common voltage signal. The arrangement directions of the bistable liquid crystal molecules 131 are different, and the reflected visible light spectra are different, and the remaining spectra are transmitted. The P state and the FC state do not require voltage to maintain. The reflection spectral band (Δλ) of the bistable liquid crystal molecules 131 is proportional to the pitch (Po) of the bistable liquid crystal molecules 131 and the average refractive index (n=(ne+no) / 2), and its formula is: Δλ=nPo. Therefore, bistable liquid crystal molecules 131 with different pitches can reflect light of different colors in the reflective state.

[0053] In another embodiment, Figure 7 is the second schematic diagram of the driving signal of the bistable liquid crystal in the transparent state in the first embodiment of the present invention. Figure 8 is the second schematic diagram of the driving signal of the bistable liquid crystal in the fog state in the first embodiment of the present invention. Figure 9This is the second schematic diagram of the driving signal of the bistable liquid crystal in the reflective state in the first embodiment of the present invention. As Figure 7 shown, when the bistable liquid crystal molecule 131 is switched to the transparent state, a first common voltage Vcom1 is applied to the common electrode 111, and a first driving voltage V1 is applied to the reflective pixel electrode 121. The first common voltage Vcom1 and the first driving voltage V1 are always AC voltages with a first voltage difference and opposite polarities. A strong vertical electric field will be formed between the common electrode 111 and the reflective pixel electrode 121, and the bistable liquid crystal molecule 131 will rotate and stop in the H state (transparent state). Among them, the first common voltage Vcom1 and the first driving voltage V1 have the same frequency, both 30~60Hz; their amplitudes can be the same or different. For example, the amplitude of the first common voltage Vcom1 is 15V~30V, and the amplitude of the first driving voltage V1 is 15V~20V.

[0054] As Figure 8As shown, when the bistable liquid crystal molecules 131 are switched to the fog state, a second common voltage Vcom2 is applied to the common electrode 111, and a second driving voltage V2 is applied to the reflective pixel electrode 121. The second common voltage Vcom2 and the second driving voltage V2 are AC voltages with a first voltage difference and opposite polarities in the first time period T1, DC voltages without a voltage difference in the second time period T2, AC voltages with a second voltage difference and opposite polarities in the third time period T3, and DC voltages without a voltage difference in the fourth time period T4. The second voltage difference is less than the first voltage difference, that is, the second driving voltage V2 first has a large voltage difference from the second common voltage Vcom2 in the first time period T1, then rapidly decreases and becomes the same as the second common voltage Vcom2 in the second time period T2. Then, the second driving voltage V2 and the second common voltage Vcom2 have a large voltage difference again in the third time period T3, and finally rapidly decreases and becomes the same as the second common voltage Vcom2. Therefore, a strong vertical electric field is first formed between the common electrode 111 and the reflective pixel electrode 121, then the vertical electric field rapidly disappears, then there is a smaller vertical electric field, and finally the vertical electric field rapidly disappears again, causing the bistable liquid crystal in the bistable liquid crystal molecules 131 to rotate and stagnate in the FC state. This is the scattering state and has a light scattering effect, which can make the effect of the bistable liquid crystal molecules 131 in the fog state better. Among them, the second common voltage Vcom2 and the second driving voltage V2 have the same frequency, both 30 - 60 Hz; the amplitude of the second common voltage Vcom2 in the first time period T1 is 15 V - 30 V, the amplitude of the second driving voltage V2 in the first time period T1 is 15 V - 20 V, the amplitude of the second common voltage Vcom2 in the third time period T3 is 0 V - 15 V, the amplitude of the second driving voltage V2 in the third time period T3 is 0 V - 30 V, and the second common voltage Vcom2 and the second driving voltage V2 are both DC common voltage signals of 0 V in the second time period T2 and the fourth time period T4.

[0055] As Figure 9As shown, when the bistable liquid crystal molecules 131 are switched to the reflective state, a third common voltage Vcom3 is applied to the common electrode 111, and a third driving voltage V3 is applied to the reflective pixel electrode 121. The third common voltage Vcom3 and the third driving voltage V3 are AC voltages with a first voltage difference and opposite polarities during the first time period T1. After that, the third common voltage Vcom3 and the third driving voltage V3 are DC voltages without a voltage difference all the time, that is, the third driving voltage V3 first has a large voltage difference from the third common voltage Vcom3 and then rapidly decreases to be the same as the third common voltage Vcom3. Therefore, a strong vertical electric field will be formed between the common electrode 111 and the reflective pixel electrode 121 first, and then the vertical electric field rapidly disappears, causing the bistable liquid crystal molecules 131 to rotate and stop in the P state, which is the reflective state. Among them, the frequencies of the third driving voltage V3 and the third common voltage Vcom3 are the same, both being 30 - 60 Hz; the amplitude of the third common voltage Vcom3 during the first time period T1 is 15 V - 30 V, the amplitude of the third driving voltage V3 during the first time period T1 is 15 V - 20 V, and the third driving voltage V3 and the third common voltage Vcom3 are both DC common voltage signals of 0 V during the second time period T2, the third time period T3, and the fourth time period T4.

[0056] Figure 10 It is one of the structural schematic diagrams of the reflective display device in Embodiment 1 of the present invention when displaying a pure red picture. Figure 11 It is the second structural schematic diagram of the reflective display device in Embodiment 1 of the present invention when displaying a pure red picture. As Figure 10 and Figure 11 shown, when the reflective display device is displaying red, all the red pixel units P3 are controlled to be in the bright state, and all the green pixel units P1 and blue pixel units P2 are controlled to be in the dark state. Specifically, as Figure 10 shown, the bistable liquid crystal molecules 131 and the black dye molecules 132 in the corresponding areas of the green pixel units P1 and blue pixel units P2 are controlled to be in a lying posture, so that the bistable liquid crystal molecules 131 in the corresponding areas of the green pixel units P1 and blue pixel units P2 are all in the reflective state. The ambient light is jointly absorbed by the color filter layer 113 and the black dye molecules 132, and the bistable liquid crystal molecules 131 reflect non-visible light to present black; and the bistable liquid crystal molecules 131 and the black dye molecules 132 in the corresponding area of the red pixel unit P3 are controlled to be in a disordered inclined state, so that the bistable liquid crystal molecules 131 in the corresponding area of the red pixel unit P3 are all in the fog state. At this time, the red pixel unit P3 reflects the light (red light) corresponding to the color of the red color filter layer 113c. Since the bistable liquid crystal molecules 131 are in the fog state, the red pixel unit P3 is in a diffuse reflection state, realizing the fog red display effect. Or, as Figure 11As shown, the bistable liquid crystal molecules 131 and the black dye molecules 132 in the corresponding areas of the green pixel unit P1 and the blue pixel unit P2 are both in a lying posture, so that the bistable liquid crystal molecules 131 in the corresponding areas of the green pixel unit P1 and the blue pixel unit P2 are both in a reflective state. The ambient light is jointly absorbed by the color resist layer 113 and the black dye molecules 132, and the bistable liquid crystal molecules 131 reflect non-visible light to present black; and the bistable liquid crystal molecules 131 and the black dye molecules 132 in the corresponding area of the red pixel unit P3 are both perpendicular to the color film substrate 11 and the array substrate 12, so that the bistable liquid crystal molecules 131 in the corresponding area of the red pixel unit P3 are both in a transparent state. At this time, the red pixel unit P3 reflects light (red light) corresponding to the color of the red color resist layer 113c.

[0057] Figure 12 It is one of the schematic structural diagrams of the reflective display device in Embodiment 1 of the present invention when displaying a pure green picture. Figure 13 It is the second schematic structural diagram of the reflective display device in Embodiment 1 of the present invention when displaying a pure green picture. As Figure 12 and Figure 13 shown, when the reflective display device displays green, all green pixel units P1 are controlled to be in the bright state, and all blue pixel units P2 and red pixel units P3 are controlled to be in the dark state. Specifically, as Figure 12 shown, the bistable liquid crystal molecules 131 and the black dye molecules 132 in the corresponding areas of the blue pixel unit P2 and the red pixel unit P3 are both in a lying posture, so that the bistable liquid crystal molecules 131 in the corresponding areas of the blue pixel unit P2 and the red pixel unit P3 are both in a reflective state. The ambient light is jointly absorbed by the color resist layer 113 and the black dye molecules 132, and the bistable liquid crystal molecules 131 reflect non-visible light to present black; and the bistable liquid crystal molecules 131 and the black dye molecules 132 in the corresponding area of the green pixel unit P1 are both in a disordered inclined state, so that the bistable liquid crystal molecules 131 in the corresponding area of the green pixel unit P1 are all in a fog state. At this time, the green pixel unit P1 reflects light (green light) corresponding to the color of the green color resist layer 113a. Since the bistable liquid crystal molecules 131 are in a fog state, the green pixel unit P1 is in a diffuse reflection state, realizing a foggy green display effect. Or, as Figure 13As shown, the bistable liquid crystal molecules 131 and the black dye molecules 132 in the corresponding areas of the blue pixel unit P2 and the red pixel unit P3 are both in a lying posture, so that the bistable liquid crystal molecules 131 in the corresponding areas of the blue pixel unit P2 and the red pixel unit P3 are both in a reflective state. The ambient light is jointly absorbed by the color filter layer 113 and the black dye molecules 132, and the bistable liquid crystal molecules 131 reflect non-visible light to present black; and the bistable liquid crystal molecules 131 and the black dye molecules 132 in the corresponding area of the green pixel unit P1 are both perpendicular to the color film substrate 11 and the array substrate 12, so that the bistable liquid crystal molecules 131 in the corresponding area of the green pixel unit P1 are both in a transparent state. At this time, the green pixel unit P1 reflects light (green light) corresponding to the color of the green color filter layer 113a.

[0058] Figure 14 It is one of the schematic structural diagrams of the reflective display device in Embodiment 1 of the present invention when displaying a pure blue picture. Figure 15 It is the second schematic structural diagram of the reflective display device in Embodiment 1 of the present invention when displaying a pure blue picture. As Figure 14 and Figure 15 shown, when the reflective display device displays blue, all the blue pixel units P2 are controlled to be in the bright state, and all the green pixel units P1 and red pixel units P3 are controlled to be in the dark state. Specifically, as Figure 12 shown, the bistable liquid crystal molecules 131 and the black dye molecules 132 in the corresponding areas of the green pixel unit P1 and the red pixel unit P3 are both in a lying posture, so that the bistable liquid crystal molecules 131 in the corresponding areas of the green pixel unit P1 and the red pixel unit P3 are both in a reflective state. The ambient light is jointly absorbed by the color filter layer 113 and the black dye molecules 132, and the bistable liquid crystal molecules 131 reflect non-visible light to present black; and the bistable liquid crystal molecules 131 and the black dye molecules 132 in the corresponding area of the blue pixel unit P2 are both in a disordered inclined state, so that the bistable liquid crystal molecules 131 in the corresponding area of the blue pixel unit P2 are all in a fog state. At this time, the blue pixel unit P2 reflects light (blue light) corresponding to the color of the blue color filter layer 113b. Since the bistable liquid crystal molecules 131 are in a fog state, the blue pixel unit P2 is in a diffuse reflection state, realizing a fog blue display effect. Or, as Figure 13As shown, the bistable liquid crystal molecules 131 and the black dye molecules 132 in the corresponding areas of the green pixel unit P1 and the red pixel unit P3 are both in a lying posture, so that the bistable liquid crystal molecules 131 in the corresponding areas of the green pixel unit P1 and the red pixel unit P3 are both in a reflective state. The ambient light is jointly absorbed by the color resist layer 113 and the black dye molecules 132, and the bistable liquid crystal molecules 131 reflect non-visible light to present black; and the bistable liquid crystal molecules 131 and the black dye molecules 132 in the corresponding area of the blue pixel unit P2 are both perpendicular to the color film substrate 11 and the array substrate 12, so that the bistable liquid crystal molecules 131 in the corresponding area of the blue pixel unit P2 are both in a transparent state. At this time, the blue pixel unit P2 reflects light (blue light) corresponding to the color of the blue color resist layer 113b.

[0059] Figure 16 It is one of the schematic structural diagrams of the reflective display device in the first embodiment of the present invention when displaying a white picture. Figure 17 It is the second schematic structural diagram of the reflective display device in the first embodiment of the present invention when displaying a white picture. As Figure 16 and Figure 17 shown, when the reflective display device displays white, all the green pixel units P1, blue pixel units P2, and red pixel units P3 are controlled to be in a bright state. Specifically, as Figure 16 shown, the bistable liquid crystal molecules 131 and the black dye molecules 132 in the corresponding area of the red pixel unit P3 are both in a disordered inclined state, so that the bistable liquid crystal molecules 131 in the corresponding area of the red pixel unit P3 are all in a fog state. At this time, the red pixel unit P3 reflects light (red light) corresponding to the color of the red color resist layer 113c. Since the bistable liquid crystal molecules 131 are in a fog state, the red pixel unit P3 is in a diffuse reflection state to achieve a fog red display effect; the bistable liquid crystal molecules 131 and the black dye molecules 132 in the corresponding area of the green pixel unit P1 are both in a disordered inclined state, so that the bistable liquid crystal molecules 131 in the corresponding area of the green pixel unit P1 are all in a fog state. At this time, the green pixel unit P1 reflects light (green light) corresponding to the color of the green color resist layer 113a. Since the bistable liquid crystal molecules 131 are in a fog state, the green pixel unit P1 is in a diffuse reflection state to achieve a fog green display effect; the bistable liquid crystal molecules 131 and the black dye molecules 132 in the corresponding area of the blue pixel unit P2 are both in a disordered inclined state, so that the bistable liquid crystal molecules 131 in the corresponding area of the blue pixel unit P2 are all in a fog state. At this time, the blue pixel unit P2 reflects light (blue light) corresponding to the color of the blue color resist layer 113b. Since the bistable liquid crystal molecules 131 are in a fog state, the blue pixel unit P2 is in a diffuse reflection state to achieve a fog blue display effect. Or, as Figure 17As shown in the figure, the bistable liquid crystal molecules 131 and the black dye molecules 132 in the area corresponding to the red pixel unit P3 are both perpendicular to the color filter substrate 11 and the array substrate 12, so that the bistable liquid crystal molecules 131 in the area corresponding to the red pixel unit P3 are all in a transparent state. At this time, the red pixel unit P3 reflects the light corresponding to the color of the red color resist layer 113c (red light); the bistable liquid crystal molecules 131 and the black dye molecules 132 in the area corresponding to the green pixel unit P1 are both perpendicular to the color filter substrate 11 and the array substrate 12, so that the bistable liquid crystal molecules 131 in the area corresponding to the green pixel unit P1 are all in a transparent state. At this time, the green pixel unit P1 reflects the light corresponding to the color of the green color resist layer 113a (green light); the bistable liquid crystal molecules 131 and the black dye molecules 132 in the area corresponding to the blue pixel unit P2 are both perpendicular to the color filter substrate 11 and the array substrate 12, so that the bistable liquid crystal molecules 131 in the area corresponding to the blue pixel unit P2 are all in a transparent state. At this time, the blue pixel unit P2 reflects the light corresponding to the color of the blue color resist layer 113b (blue light). Among them, white light is formed by mixing red / green / blue three-color light with each other.

[0060] Figure 18 is a schematic structural diagram of the reflective display device in the first embodiment of the present invention when displaying a pure black picture. As Figure 18 shown, when the reflective display device is displaying a pure black picture, all the green pixel units P1, blue pixel units P2 and red pixel units P3 are controlled to be in a dark state. Specifically, the bistable liquid crystal molecules 131 and the black dye molecules 132 in the areas corresponding to the green pixel unit P1, blue pixel unit P2 and red pixel unit P3 are all in a lying posture, so that the bistable liquid crystal molecules 131 in the areas corresponding to the green pixel unit P1, blue pixel unit P2 and red pixel unit P3 are all in a reflective state. The ambient light is jointly absorbed by the color color resist layer 113 and the black dye molecules 132, and the bistable liquid crystal molecules 131 reflect non-visible light to present black.

[0061] In this embodiment, the reflective display device can also display colors. When the reflective display device displays colors, it is only necessary to control the corresponding green pixel unit P1, blue pixel unit P2, and red pixel unit P3 to be in the bright state. Specifically, control the bistable liquid crystal molecules 131 and black dye molecules 132 in the corresponding area of the red pixel unit P3 to be perpendicular to the color film substrate 11 and the array substrate 12 or to be in a disordered inclined state, so that the bistable liquid crystal molecules 131 in the corresponding area of the red pixel unit P3 are in a transparent state or a fog state. At this time, the red pixel unit P3 reflects light (red light) corresponding to the color of the red color resist layer 113c; and control the bistable liquid crystal molecules 131 and black dye molecules 132 in the corresponding area of the corresponding green pixel unit P1 to be perpendicular to the color film substrate 11 and the array substrate 12 or to be in a disordered inclined state, so that the bistable liquid crystal molecules 131 in the corresponding area of the green pixel unit P1 are in a transparent state or a fog state. At this time, the green pixel unit P1 reflects light (green light) corresponding to the color of the green color resist layer 113a; and control the bistable liquid crystal molecules 131 and black dye molecules 132 in the corresponding area of the corresponding blue pixel unit P2 to be perpendicular to the color film substrate 11 and the array substrate 12 or to be in a disordered inclined state, so that the bistable liquid crystal molecules 131 in the corresponding area of the blue pixel unit P2 are in a transparent state or a fog state. At this time, the blue pixel unit P2 reflects light (blue light) corresponding to the color of the blue color resist layer 113b. According to the principle of color mixing of red, green, and blue light, various colors of light are formed, thereby realizing color display.

[0062] [Embodiment 2] Figure 19 is a schematic structural diagram of the reflective display device in the initial state in Embodiment 2 of the present invention. As Figure 19 shown, the reflective display device and driving method provided in Embodiment 2 of the present invention are basically the same as those in Embodiment 1 ( Figures 2 to 18 ), the difference is that: In this embodiment, the number of bistable liquid crystal cells 10 is one, so that single-sided full-color reflection display can be realized, and the thickness of the reflective display device is thinner than that in Embodiment 1.

[0063] Those skilled in the art should understand that the rest of the structure and working principle of this embodiment are the same as those in Embodiment 1, and will not be described here again.

[0064] In this document, the orientation terms such as "upper", "lower", "left", "right", "front", and "back" are defined based on the positions of the structures in the accompanying drawings and their relative positions to each other, solely for the clarity and convenience of expressing the technical solution. It should be understood that the use of these orientation terms should not limit the scope of protection claimed in this application. It should also be understood that the terms "first" and "second" used herein are only for distinction in name and do not limit the quantity and sequence.

[0065] As described above, these are merely preferred embodiments of the present invention and do not impose any formal limitations on the present invention. Although the present invention has been disclosed above in preferred embodiments, it is not intended to limit the present invention. Any person skilled in the relevant art can make some modifications or refinements using the disclosed technical content within the scope of the technical solution of the present invention, which are equivalent embodiments of equivalent changes. However, as long as the content of the technical solution of the present invention is not departed from, any simple modifications, equivalent changes, and refinements made to the above embodiments based on the technical essence of the present invention still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A reflective display device, characterized in that, It includes a bistable liquid crystal cell (10), the bistable liquid crystal cell (10) includes a color filter substrate (11), an array substrate (12) disposed opposite to the color filter substrate (11), and a liquid crystal layer (13) located between the color filter substrate (11) and the array substrate (12). The liquid crystal layer (13) includes bistable liquid crystal molecules (131) and black dye molecules (132) mixed with the bistable liquid crystal molecules (131). The black dye molecules (132) rotate synchronously with the bistable liquid crystal molecules (131). All the bistable liquid crystal molecules (131) reflect non-visible light in the reflective state. A reflective pixel electrode (121) is provided on the array substrate (12), and a common electrode (111) matching the reflective pixel electrode (121) is provided on the color filter substrate (11). The bistable liquid crystal cell (10) has a plurality of pixel units (P) arranged in an array. The reflective pixel electrode (121) is correspondingly provided in each pixel unit (P), and a color resist layer (113) is provided on the color filter substrate (11) in the area corresponding to the pixel unit (P). When the pixel unit (P) is in the bright state, the bistable liquid crystal molecules (131) in the corresponding area of the pixel unit (P) are all in the transparent state or the fog state; when the pixel unit (P) is in the dark state, the bistable liquid crystal molecules (131) in the corresponding area of the pixel unit (P) are all in the reflective state.

2. The reflective display device according to claim 1, wherein The bistable liquid crystal molecules (131) are infrared bistable liquid crystal molecules and reflect infrared light in the reflective state. Alternatively, the bistable liquid crystal molecules (131) are ultraviolet bistable liquid crystal molecules and reflect ultraviolet light in the reflective state.

3. The reflective display device according to claim 1, wherein Among the plurality of pixel units (P), there are green pixel units (P1), blue pixel units (P2), and red pixel units (P3). The color resist layer (113) includes a green color resist layer (113a), a blue color resist layer (113b), and a red color resist layer (113c). The green color resist layer (113a) corresponds to the green pixel unit (P1), the blue color resist layer (113b) corresponds to the blue pixel unit (P2), and the red color resist layer (113c) corresponds to the red pixel unit (P3).

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

5. The reflective display device according to claim 4, wherein The projection of the reflective pixel electrode (121) on the color filter substrate (11) partially overlaps with the black matrix (112).

6. The reflective display device according to any one of claims 1-5, characterized in that, The reflective display device includes an absorbing layer (20), and the absorbing layer (20) is provided on one side of the bistable liquid crystal cell (10) close to the array substrate (12). The absorbing layer (20) is used to absorb the light passing through the bistable liquid crystal cell (10).

7. The reflective display device according to any one of claims 1-5, characterized in that, The number of the bistable liquid crystal cells (10) is two and they are stacked on top of each other, and the array substrates (12) of the two bistable liquid crystal cells (10) face each other.

8. A driving method for a reflective display device, characterized in that, For driving a reflective display device as described in any one of claims 1-7, the driving method includes: When the pixel unit (P) is in the bright state, controlling all the bistable liquid crystal molecules (131) in the corresponding area of the pixel unit (P) to be in the transparent state or the fog state. At this time, the pixel unit (P) reflects light corresponding to the color of the color filter layer (113); when the pixel unit (P) is in the dark state, controlling all the bistable liquid crystal molecules (131) in the corresponding area of the pixel unit (P) to be in the reflective state, and ambient light is jointly absorbed by the color filter layer (113) and the black dye molecules (132).

9. The driving method of the reflective display device according to claim 8, characterized in that, Among the multiple pixel units (P), there are green pixel units (P1), blue pixel units (P2), and red pixel units (P3). The color filter layer (113) includes a green color filter layer (113a), a blue color filter layer (113b), and a red color filter layer (113c). The green color filter layer (113a) corresponds to the green pixel unit (P1), the blue color filter layer (113b) corresponds to the blue pixel unit (P2), and the red color filter layer (113c) corresponds to the red pixel unit (P3). The driving method includes: When the reflective display device displays green, controlling all the green pixel units (P1) to be in the bright state, and controlling all the blue pixel units (P2) and the red pixel units (P3) to be in the dark state; when the reflective display device displays blue, controlling all the blue pixel units (P2) to be in the bright state, and controlling all the green pixel units (P1) and the red pixel units (P3) to be in the dark state; when the reflective display device displays red, controlling all the red pixel units (P3) to be in the bright state, and controlling all the green pixel units (P1) and the blue pixel units (P2) to be in the dark state; when the reflective display device displays white, controlling all the green pixel units (P1), the blue pixel units (P2), and the red pixel units (P3) to be in the bright state.

10. The driving method of the reflective display device according to claim 8, characterized in that, The driving method includes: When the bistable liquid crystal molecules (131) are switched to the transparent state, applying a first common voltage (Vcom1) to the common electrode (111), and applying a first driving voltage (V1) to the reflective pixel electrode (121). The first common voltage (Vcom1) and the first driving voltage (V1) are always AC voltages with a first voltage difference and opposite polarities. When the bistable liquid crystal molecules (131) are switched to the fog state, a second common voltage (Vcom2) is applied to the common electrode (111), and a second driving voltage (V2) is applied to the reflective pixel electrode (121). The second common voltage (Vcom2) and the second driving voltage (V2) are AC voltages with a first voltage difference and opposite polarities in the first time period (T1), the second common voltage (Vcom2) and the second driving voltage (V2) are DC voltages without a voltage difference in the second time period (T2), the second common voltage (Vcom2) and the second driving voltage (V2) are AC voltages with a second voltage difference and opposite polarities in the third time period (T3), the second common voltage (Vcom2) and the second driving voltage (V2) are DC voltages without a voltage difference in the fourth time period (T4), and the second voltage difference is less than the first voltage difference; When the bistable liquid crystal molecules (131) are switched to the reflective state, a third common voltage (Vcom3) is applied to the common electrode (111), and a third driving voltage (V3) is applied to the reflective pixel electrode (121). The third common voltage (Vcom3) and the third driving voltage (V3) are AC voltages with a first voltage difference and opposite polarities in the first time period (T1), and thereafter, the third common voltage (Vcom3) and the third driving voltage (V3) are always DC voltages without a voltage difference.

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