Display apparatus and control method

Abstract

The invention discloses a display device and a control method, the display device comprises a bistable liquid crystal box and a pressure detection unit, the bistable liquid crystal box is used for controlling picture display in a reflection mode, and the pressure detection unit is used for detecting a real-time pressure value borne by the display device; when it is detected that the real-time pressure value borne by the display device is larger than or equal to the preset pressure value, the bistable liquid crystal box is controlled to refresh the same picture displayed at present again. The pressure detection unit is arranged in the display device to detect the real-time pressure value borne by the display device, and when it is detected that the real-time pressure value is larger than or equal to the preset pressure value, the bistable liquid crystal box is controlled to refresh the currently displayed same picture again, so that the influence of external pressure on the display picture is eliminated, and the display effect is improved. The problem of non-uniform display is avoided; and the refreshing state of the bistable liquid crystal box under the external pressure is accurately controlled, so that the refreshing power consumption of the bistable liquid crystal box is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a display device and a control method. BACKGROUND

[0002] The display panel has the advantages of thinness, durability, low power consumption and environmental protection, but it needs to be used with a backlight source, resulting in a thick module and high cost. Electronic paper display (reflective display) has become a display that meets the needs of the public. Electronic paper display can use external light source to display images, unlike liquid crystal display which needs a backlight source. Therefore, in the outdoor environment with strong sunlight, the information on the electronic paper can still be clearly seen without the problem of viewing angle. In addition, electronic paper display has the advantages of power saving, high reflectivity and contrast ratio, and is now widely used in electronic readers (such as electronic books and electronic newspapers) or other electronic components (such as price tags).

[0003] The existing electronic paper display usually adopts E-Ink microcapsule technology (microcapsule electronic ink technology), SiPix microcup technology (microcup type electrophoretic display technology), Bridgestone electronic liquid powder technology, cholesteric liquid crystal molecule display (CLCD) technology, micro-electro-mechanical system (MEMS) technology or electrowetting technology. However, the existing electronic paper display technology is not very mature compared with liquid crystal display technology, the production efficiency is low, the manufacturing cost is relatively high, and the existing electronic paper display cannot realize color display.

[0004] Figure 1 is a schematic diagram of the structure of the cholesteric liquid crystal cell in the prior art, as shown in Figure 1 The display device using cholesteric liquid crystal molecules in the prior art can only reflect one color and transmit light of other colors due to the requirement of the cholesteric liquid crystal molecule pitch. Therefore, the display device with single-layer cholesteric liquid crystal molecules is mostly displayed in the form of yellow background and black characters or black background and yellow characters, black background and red characters or red background and black characters, which cannot realize black background and white characters or white background and black characters like a book, thus greatly limiting the product application. In order to realize white display or color display, the bistable liquid crystal display is usually overlapped with the conventional liquid crystal display panel, so that monochrome reflective display and color transmissive display can be realized.

[0005] Figure 2 is a schematic diagram of the structure of the cholesteric liquid crystal cell in the prior art after being pressed in the reflective state. Figure 3 is a schematic diagram of the structure of the cholesteric liquid crystal cell in the prior art after the pressure disappears in the reflective state. Figure 4is a structural schematic diagram of a cholesteric phase liquid crystal cell in a fog state after being pressed in the prior art. Figure 5 is a structural schematic diagram of a cholesteric phase liquid crystal cell after the pressure disappears in a fog state in the prior art. As shown in Figures 2 to 5 , since the cholesteric phase liquid crystal molecules have a bistable state characteristic, no driving voltage is required to maintain in the reflection state and the fog state, low-power consumption display can be achieved, for example, when used in electronic tags, it is possible to not consume power for several days. However, the cholesteric phase liquid crystal cell will be pressed to the cholesteric phase liquid crystal molecules under the action of a larger external force, resulting in a phase state transition, and cannot recover by itself. For example, the reflection state is pressed to change to the fog state Figure 2 , the fog state still remains after the external force disappears Figure 3 ; or the fog state is pressed to change to the reflection state Figure 4 , the fog state still remains after the external force disappears Figure 5 , cannot recover by itself, so that the display screen changes in color, Mura (display unevenness) is formed, affecting the display effect and reducing the use experience. SUMMARY

[0006] In order to overcome the shortcomings and deficiencies in the prior art, the purpose of the present application is to provide a display device and a control method to solve the problem that the bistable liquid crystal molecule display device in the prior art will appear Mura after being pressed by an external force.

[0007] The purpose of the present application is achieved by the following technical solutions: The present application provides a display device, comprising: a bistable liquid crystal cell for controlling picture display in a reflection mode, and a pressure detection unit for detecting a real-time pressure value borne by the display device. When it is detected that the real-time pressure value borne by the display device is greater than or equal to a preset pressure value, the bistable liquid crystal cell is controlled to refresh the same picture currently displayed.

[0008] Further, the bistable liquid crystal cell comprises an opposite substrate, a first array substrate oppositely arranged with the opposite substrate, and a bistable liquid crystal layer located between the opposite substrate and the first array substrate, the opposite substrate is provided with a first common electrode, and the first array substrate is provided with a first pixel electrode matched with the first common electrode. The pressure detection unit is arranged between the opposite substrate and the first array substrate.

[0009] Further, the display device comprises a transmissive display liquid crystal cell and a backlight module, the bistable liquid crystal cell, the transmissive display liquid crystal cell and the backlight module are sequentially stacked, and the transmissive display liquid crystal cell is used to control picture display in a transmissive mode.

[0010] Furthermore, the pressure detection unit is located between the bistable liquid crystal cell and the transmissive display liquid crystal cell.

[0011] Furthermore, the pressure detection unit includes a strain gauge pressure sensor, a piezoresistive pressure sensor, a capacitive pressure sensor, or a piezoelectric pressure sensor.

[0012] Furthermore, the display device has a display area and a non-display area located around the periphery of the display area, and the pressure detection unit is located in the non-display area.

[0013] Furthermore, the pressure detection unit is located near the top corner of the non-display area, and / or the pressure detection unit is located in the middle area near the edge of the non-display area.

[0014] Furthermore, the capacitive pressure sensor includes a first electrode, a dielectric layer, and a second electrode stacked sequentially, wherein both the first electrode and the second electrode are annular structures arranged around the periphery of the display area.

[0015] This application also provides a control method for a display device, used to control the display device as described above, the control method comprising: Detect the real-time pressure value experienced by the display device; The real-time pressure value is compared with the preset pressure value. When the real-time pressure value is greater than or equal to the preset pressure value, the bistable liquid crystal cell is controlled to refresh the currently displayed same image; when the real-time pressure value is less than the preset pressure value, the bistable liquid crystal cell is controlled to maintain the currently displayed image.

[0016] Furthermore, the display device includes a transmissive liquid crystal cell and a backlight module, wherein the bistable liquid crystal cell, the transmissive liquid crystal cell, and the backlight module are stacked sequentially. In reflection mode, both the transmissive display liquid crystal cell and the backlight module are controlled to be in a turned-off state, and the bistable liquid crystal cell is controlled to display the image. In transmissive mode, both the transmissive display liquid crystal cell and the backlight module are controlled to be in the open state, the entire surface of the bistable liquid crystal cell is controlled to be in a fog or transparent state, and the transmissive display liquid crystal cell is controlled to display the image.

[0017] The beneficial effects of this invention are as follows: By incorporating a pressure detection unit into the display device, the unit can detect the real-time pressure value borne by the display device. When the detected real-time pressure value is greater than or equal to a preset pressure value, the bistable liquid crystal cell is controlled to refresh the currently displayed image, thereby eliminating the influence of external pressure on the display image, avoiding uneven display, and improving display effect and user experience. Since the bistable liquid crystal cell is only controlled to refresh the currently displayed image when the pressure value detected by the pressure detection unit exceeds the phase transition threshold of the bistable liquid crystal molecules, the refresh state of the bistable liquid crystal cell under external pressure can be precisely controlled, thus reducing the power consumption of the bistable liquid crystal cell during refresh. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a cholesteric phase liquid crystal cell in the prior art.

[0019] Figure 2 This is a schematic diagram of the structure of a cholesteric liquid crystal cell in the reflective state after being pressed in the prior art.

[0020] Figure 3 This is a schematic diagram of the structure of a cholesteric liquid crystal cell after the disappearance of reflective pressure in the prior art.

[0021] Figure 4 This is a schematic diagram of the structure of a cholesteric liquid crystal cell after it is pressed in a foggy state in the prior art.

[0022] Figure 5 This is a schematic diagram of the structure of a cholesteric liquid crystal cell after the fog pressure disappears in the prior art.

[0023] Figure 6 This is a schematic diagram of the display device in its initial state according to Embodiment 1 of the present invention.

[0024] Figure 7 This is a schematic diagram of the planar structure of the first array substrate in Embodiment 1 of the present invention.

[0025] Figure 8 This is a schematic diagram of the planar structure of the second array substrate in Embodiment 1 of the present invention.

[0026] Figure 9 This is one of the structural schematic diagrams of the pressure detection unit distributed on the display device in Embodiment 1 of the present invention.

[0027] Figure 10 This is the second schematic diagram of the distribution of the pressure detection unit on the display device in Embodiment 1 of the present invention.

[0028] Figure 11 This is a schematic diagram illustrating the principle of the three state transformations of cholesteric liquid crystal molecules in this invention.

[0029] Figure 12 This is a schematic diagram of the driving signals for the three state transitions of cholesteric liquid crystal molecules in this invention.

[0030] Figure 13 This is a schematic diagram of the control flow of the control method for the display device in Embodiment 1 of the present invention.

[0031] Figure 14 This is a schematic diagram of signal transmission in the display device according to Embodiment 1 of the present invention.

[0032] Figure 15 This is a schematic diagram of the display device in reflection mode according to Embodiment 1 of the present invention.

[0033] Figure 16 This is a schematic diagram of the display device in transmission mode according to Embodiment 1 of the present invention.

[0034] Figure 17 This is a schematic diagram of the display device in its initial state according to Embodiment 2 of the present invention.

[0035] Figure 18 This is a schematic diagram of the distribution of the pressure detection unit on the display device in Embodiment 2 of the present invention.

[0036] Figure 19 This is a schematic diagram of the pressure detection unit after it is pressed in Embodiment 2 of the present invention.

[0037] Figure 20 This is a graph showing the relationship between the capacitance value and pressure of the pressure detection unit in Embodiment 2 of the present invention.

[0038] Figure 21 This is a schematic diagram of the display device in its initial state according to Embodiment 3 of the present invention. Detailed Implementation

[0039] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following detailed description, in conjunction with the accompanying drawings and preferred embodiments, provides a detailed explanation of the specific implementation methods, structures, features, and effects of the display device and control method proposed according to the present invention: [Example 1] Figure 6 This is a schematic diagram of the display device in its initial state according to Embodiment 1 of the present invention. Figure 7 This is a schematic diagram of the planar structure of the first array substrate in Embodiment 1 of the present invention. Figure 8 This is a schematic diagram of the planar structure of the second array substrate in Embodiment 1 of the present invention.

[0040] like Figures 6 to 8As shown, a display device provided in Embodiment 1 of the present invention includes: a bistable liquid crystal cell 10 and a pressure detection unit 20. The bistable liquid crystal cell 10 is used to control the display of the screen in the reflection mode, and the pressure detection unit 20 is used to detect the real-time pressure value borne by the display device.

[0041] The bistable liquid crystal cell 10 includes a counter substrate 11, a first array substrate 12 disposed opposite to the counter substrate 11, and a bistable liquid crystal layer 13 located between the counter substrate 11 and the first array substrate 12. The bistable liquid crystal layer 13 uses cholesteric liquid crystal molecules, which, in their reflective state, can reflect light corresponding to their pitch. Of course, the bistable liquid crystal layer 13 can also use other bistable liquid crystal molecules, such as cholesteric liquid crystal molecules.

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

[0043] like Figure 7 As shown, a first array substrate 12 is provided with multiple first scan lines 101 and multiple first data lines 102. The multiple first scan lines 101 and multiple first data lines 102 are mutually insulated and intersecting to form multiple first pixel units P1. Each first pixel unit P1 is provided with a first thin-film transistor 103 and a first pixel electrode 121. The first pixel electrode 121 is electrically connected to the first scan line 101 and the first data line 102 adjacent to the first thin-film transistor 103 through the first thin-film transistor 103. The first thin-film transistor 103 includes a first gate, a first active layer, a first drain, and a first source. The first gate and the first scan line 101 are located on the same layer and are electrically connected. The first gate and the first active layer are isolated by an insulating layer. The first source is electrically connected to the first data line 102. The first drain is electrically connected to the first pixel electrode 121 through a contact hole.

[0044] Cholesteric liquid crystal molecules possess three stable textures: P-state (Planar, reflective), FC-state (FocalConic, hazy), and H-state (transparent). In the P-state, the reflection spectrum of cholesteric liquid crystal molecules is in the visible spectrum, reflecting bright colored light. The specific color reflected can be set according to the pitch of the cholesteric liquid crystal molecules. In the FC-state, cholesteric liquid crystal molecules no longer reflect the aforementioned colored light, and light can be scattered and passed through them. In the H-state, cholesteric liquid crystal molecules no longer reflect the aforementioned colored light, and light can pass directly through them without scattering. Under a certain electric field, these three states can interconvert. The reflection spectrum band (Δλ) of cholesteric liquid crystal molecules is proportional to the pitch (Po) and average refractive index (n=(ne+no) / 2) of the cholesteric liquid crystal molecules, with the formula: Δλ=nPo. Therefore, cholesteric liquid crystal molecules with different pitches can reflect different colors of light in the reflective state.

[0045] Figure 11 This is a schematic diagram illustrating the principle of the three-state transformation of cholesteric liquid crystal molecules in this invention. Figure 12 This is a schematic diagram of the driving signals for the three state transitions of cholesteric liquid crystal molecules in this invention. (See diagram below.) Figure 11 and Figure 12As shown, a common voltage signal Vcom is applied to the first common electrode 111, and a first electrical signal V1 is continuously applied to the first pixel electrode 121. There is a first voltage difference (about 20V) between the common voltage signal Vcom and the first electrical signal V1. A strong vertical electric field is formed between the first common electrode 111 and the first pixel electrode 121, and the cholesteric liquid crystal molecules rotate and stagnate in the H state (transparent state). A common voltage signal Vcom is applied to the first common electrode 111, and a second electrical signal V2 is applied to the first pixel electrode 121. There is a second voltage difference (e.g., 30V) between the second electrical signal V2 and the common voltage signal Vcom. The second electrical signal V2 directly becomes the same as the common voltage signal Vcom at a first preset time. That is, the second electrical signal V2 first has a large voltage difference with the common voltage signal Vcom, and then rapidly decreases and becomes the same as the common voltage signal Vcom. Therefore, a strong vertical electric field is first formed between the first common electrode 111 and the first pixel electrode 121. Then the vertical electric field disappears rapidly, causing the cholesteric liquid crystal molecules to first rotate into the H state, and then rotate and stagnate in the P state, which is the reflective state. A common voltage signal Vcom is applied to the first common electrode 111, and a third electrical signal V3 is applied to the first pixel electrode 121. A first voltage difference (e.g., 20V) exists between the third electrical signal V3 and the common voltage signal Vcom. The third electrical signal V3 gradually becomes the same as the common voltage signal Vcom within a second preset time period; that is, the third electrical signal V3 initially has a large voltage difference with the common voltage signal Vcom, then slowly decreases and becomes the same as the common voltage signal Vcom. The first preset time is less than the second preset time. Therefore, a strong vertical electric field is initially formed between the first common electrode 111 and the first pixel electrode 121, and then the vertical electric field slowly disappears, causing the cholesteric liquid crystal molecules to first rotate into the H state, and then rotate and remain stationary in the FC state. This is a scattering state and has a light-scattering effect. The cholesteric liquid crystal molecules have different arrangement directions, resulting in different reflected visible light spectra. The remaining spectrum is transmitted, and the P state and FC state do not require voltage to maintain.

[0046] In this embodiment, the display device further includes a transmissive liquid crystal cell 30 and a backlight module 50. The bistable liquid crystal cell 10, the transmissive liquid crystal cell 30, and the backlight module 50 are stacked sequentially. The transmissive liquid crystal cell 30 is used to control the image display in transmissive mode, and the backlight module 50 is used to provide a backlight source for the transmissive liquid crystal cell 30 in transmissive mode. Optionally, the pressure detection unit 20 is disposed between the bistable liquid crystal cell 10 and the transmissive liquid crystal cell 30, and the bistable liquid crystal cell 10 and the transmissive liquid crystal cell 30 are bonded together with an adhesive (e.g., OCA adhesive). Of course, in other embodiments, the pressure detection unit 20 may also be disposed between the opposing substrate 11 and the first array substrate 12, that is, disposed within the bistable liquid crystal cell 10.

[0047] The transmissive display liquid crystal cell 30 includes a color filter substrate 31, a second array substrate 32 disposed opposite to the color filter substrate 31, and a liquid crystal layer 33 located between the color filter substrate 31 and the second array substrate 32. Preferably, the liquid crystal layer 33 uses positive liquid crystal molecules, that is, liquid crystal molecules with positive dielectric anisotropy. Figure 6 As shown, in the initial state, the positive liquid crystal molecules in the liquid crystal layer 33 are aligned parallel to the color filter substrate 31 and the second array substrate 32. The alignment directions of the positive liquid crystal molecules on the side closer to the color filter substrate 31 and the positive liquid crystal molecules on the side closer to the second array substrate 32 are parallel or antiparallel.

[0048] The color filter substrate 31 has color resist layers 312 arranged in an array and black matrix 311 separating the color resist layers 312. The color resist layers 312 include color resist materials of red (R), green (G) and blue (B) colors, and correspondingly form sub-pixels of red (R), green (G) and blue (B) colors.

[0049] like Figure 6 and Figure 8 As shown, the second array substrate 32 has multiple second scan lines 301 and multiple second data lines 302 on the side facing the liquid crystal layer 33. The multiple second scan lines 301 and multiple second data lines 302 are mutually insulated and intersecting to form multiple second pixel units P2. The second array substrate 32 has a second thin film transistor 303 and a second pixel electrode 322 in each second pixel unit P2. The second pixel electrode 322 is electrically connected to the second scan line 301 and the second data line 302 adjacent to the second thin film transistor 303 through the second thin film transistor 303. The second thin film transistor 303 includes a second gate, a second active layer, a second drain, and a second source. The second gate and the second scan line 301 are located on the same layer and are electrically connected. The second gate and the second active layer are isolated by an insulating layer. The second source is electrically connected to the second data line 302. The second drain is electrically connected to the second pixel electrode 322 through a contact hole.

[0050] Furthermore, each first pixel unit P1 corresponds to at least one second pixel unit P2. For example, the first pixel unit P1 and the second pixel unit P2 are in one-to-one correspondence. Of course, each first pixel unit P1 can also correspond to multiple second pixel units P2.

[0051] In this embodiment, a second common electrode 321 is further provided on the side of the second array substrate 32 facing the liquid crystal layer 33. The second common electrode 321 and the second pixel electrode 322 are located on different layers and are insulated from each other by an insulating layer. The second common electrode 321 may be located above or below the second pixel electrode 322. Figure 6The diagram shows the second common electrode 321 located below the second pixel electrode 322. Preferably, the second common electrode 321 is a planar electrode with its entire surface disposed, and the second pixel electrode 322 is a slit electrode with multiple electrode strips within each second pixel unit P2 to form a fringe field switching (FFS) mode. Of course, in other embodiments, the second pixel electrode 322 and the second common electrode 321 may be located on the same layer, but they are insulated from each other. Each of the second pixel electrode 322 and the second common electrode 321 may include multiple electrode strips, and the electrode strips of the second pixel electrode 322 and the second common electrode 321 are arranged alternately to form an in-plane switching (IPS) mode; or, in other embodiments, the second array substrate 32 has the second pixel electrode 322 on the side facing the liquid crystal layer 33, and the color filter substrate 31 has the second common electrode 321 on the side facing the liquid crystal layer 33 to form a TN mode or a VA mode. For further descriptions of the TN mode and VA mode, please refer to the prior art, which will not be repeated here.

[0052] Furthermore, a first polarizer 41 is provided on the side of the transmissive liquid crystal cell 30 away from the bistable liquid crystal cell 10, and a second polarizer 42 is provided between the bistable liquid crystal cell 10 and the transmissive liquid crystal cell 30. The light transmission axis of the first polarizer 41 and the light transmission axis of the second polarizer 42 are perpendicular to each other.

[0053] The opposing substrate 11, the first array substrate 12, the color filter substrate 31, and the second array substrate 32 can be made of materials such as glass, acrylic, and polycarbonate. The materials of the first common electrode 111, the first pixel electrode 121, the second common electrode 321, and the second pixel electrode 322 can be indium tin oxide (ITO) or indium zinc oxide (IZO), etc.

[0054] The pressure detection unit 20 includes a strain gauge pressure sensor, a piezoresistive pressure sensor, a capacitive pressure sensor, or a piezoelectric pressure sensor. In this embodiment, the pressure detection unit 20 is a piezoresistive pressure sensor, which is a resistor made using the piezoresistive effect. Its material is a semiconductor material, which is sensitive to pressure. When pressure is applied, the internal crystal lattice structure deforms, causing a change in the mobility of charge carriers or holes, and its resistivity also changes, resulting in a significant decrease in resistance.

[0055] Figure 9 This is one of the structural schematic diagrams of the pressure detection unit distributed on the display device in Embodiment 1 of the present invention. Figure 10 This is a second schematic diagram showing the distribution of the pressure detection unit on the display device in Embodiment 1 of the present invention. Figure 9 and Figure 10As shown, the display device has a display area 110 and a non-display area 120 located around the periphery of the display area 110, and the pressure detection unit 20 is disposed in the non-display area 120. Optionally, as... Figure 9 As shown, the pressure detection unit 20 is located at the top corner near the non-display area 120; of course, as... Figure 10 As shown, the pressure detection unit 20 can also be located in the middle area near the edge of the non-display area 120; or, the pressure detection unit 20 can be located at the top corner of the non-display area 120 and in the middle area of ​​the edge of the non-display area 120, thereby increasing the accuracy of pressure detection.

[0056] Figure 13 This is a schematic diagram of the control flow of the control method for the display device in Embodiment 1 of the present invention. Figure 14 This is a schematic diagram of signal transmission in the display device according to Embodiment 1 of the present invention. Figure 13 and Figure 14 As shown, this application also provides a control method for a display device, used to control the display device as described above. The control method includes: The device displays the real-time pressure value it is subjected to. Compare the real-time pressure value with the preset pressure value. When the real-time pressure value is greater than or equal to the preset pressure value, the bistable liquid crystal cell 10 is controlled to refresh the currently displayed same screen; when the real-time pressure value is less than the preset pressure value, the bistable liquid crystal cell 10 is controlled to maintain the currently displayed screen.

[0057] Specifically, if the pressure detection unit 20 does not detect that the display device is being pressed, or if the real-time pressure value is less than the preset pressure value, it maintains the bistable display mode and does not require applying a screen drive signal. If the pressure detection unit 20 detects that the real-time pressure value of the display device being pressed is greater than or equal to the preset pressure value, the screen drive chip re-inputs the screen drive signal according to the currently displayed image of the bistable liquid crystal cell, that is, it re-applies the corresponding state drive signal to all first pixel units P1. For example, when the corresponding first pixel unit is in the FC state, it inputs the corresponding FC state drive waveform; when the corresponding first pixel unit is in the P state, it inputs the corresponding P state drive waveform. Figure 14As shown, when the real-time pressure value (F) is 0N, the impedance of the piezoresistive pressure sensor (R2) is 1000K ohms, and the sampling voltage of the DAC (analog-to-digital converter) is 3V. When the real-time pressure value reaches the threshold (preset pressure value), the pressure on the piezoresistive pressure sensor is negatively correlated with its impedance, which is 50K, and the DAC voltage is 1.1V. The reference voltage Vref (reference voltage) is set to 1.1V. When the real-time pressure is greater than the threshold, the impedance of the piezoresistive pressure sensor is less than 50K, the DAC voltage is less than 1.1V, triggering the reset signal (Reset) of the bistable liquid crystal cell 10 driver, and refreshing the correct image. The preset pressure value can be set according to actual conditions; for example, it can be the minimum pressure required for the bistable liquid crystal molecules to undergo a phase transition.

[0058] Figure 15 This is a schematic diagram of the display device in reflection mode according to Embodiment 1 of the present invention. Figure 16 This is a schematic diagram of the display device in transmission mode according to Embodiment 1 of the present invention. Figure 15 and Figure 16 As shown, the control method includes: In reflective mode, both the transmissive display liquid crystal cell 30 and the backlight module 50 are turned off, and the bistable liquid crystal cell 10 is controlled to display the image. Specifically, in reflective mode, neither the transmissive display liquid crystal cell 30 nor the backlight module 50 is operational; the display of the image is controlled by the bistable liquid crystal cell 10. Figure 12 and Figure 15As shown, for the first pixel unit P1 in the bright state: a common voltage signal Vcom is applied to the first common electrode 111, and a second electrical signal V2 is applied to the corresponding first pixel electrode 121. There is a voltage difference (e.g., 30V) between the second electrical signal V2 and the common voltage signal Vcom, and the second electrical signal V2 directly becomes the same as the common voltage signal Vcom at the first preset time. That is, the second electrical signal V2 first has a large voltage difference with the common voltage signal Vcom, and then rapidly decreases and becomes the same as the common voltage signal Vcom. Therefore, a strong vertical electric field is first formed between the first common electrode 111 and the first pixel electrode 121, and then the vertical electric field disappears rapidly, causing the corresponding cholesteric liquid crystal molecules to first rotate to the H state, and then rotate and remain in the P state, which is a reflective state, so as to reflect ambient light and present a bright state. For the first pixel unit P1 in the dark state: a common voltage signal Vcom is applied to the first common electrode 111, and a third electrical signal V3 is applied to the corresponding first pixel electrode 121. There is a first voltage difference (e.g., 20V) between the third electrical signal V3 and the common voltage signal Vcom. The third electrical signal V3 gradually becomes the same as the common voltage signal Vcom within a second preset time period; that is, the third electrical signal V3 initially has a large voltage difference with the common voltage signal Vcom, then slowly decreases and becomes the same as the common voltage signal Vcom. The first preset time is less than the second preset time. Therefore, a strong vertical electric field is first formed between the first common electrode 111 and the first pixel electrode 121, and then the vertical electric field slowly disappears, causing the corresponding cholesteric liquid crystal molecules to first rotate to the H state, and then rotate and remain in the FC state. Light passes through the bistable liquid crystal cell 10 and appears dark. Alternatively, the cholesteric liquid crystal molecules corresponding to the first pixel unit P1 in the dark state can be controlled to be in the H state.

[0059] In transmissive mode, both the transmissive display liquid crystal cell 30 and the backlight module 50 are turned on, the bistable liquid crystal cell 10 is controlled to be either fogged or transparent, and the transmissive display liquid crystal cell 30 is controlled to display the image. Specifically, in reflective mode, both the transmissive display liquid crystal cell 30 and the backlight module 50 operate normally, the bistable liquid crystal cell 10 is either fogged or transparent, and the image display is controlled by the transmissive display liquid crystal cell 30. For example... Figure 12 and Figure 16As shown, for the bistable liquid crystal display cell 10: a common voltage signal Vcom is applied to the first common electrode 111, and a third electrical signal V3 is applied to all the first pixel electrodes 121. There is a first voltage difference (e.g., 20V) between the third electrical signal V3 and the common voltage signal Vcom, and the third electrical signal V3 gradually becomes the same as the common voltage signal Vcom within a second preset time. That is, the third electrical signal V3 initially has a large voltage difference with the common voltage signal Vcom, then slowly decreases and becomes the same as the common voltage signal Vcom. The first preset time is less than the second preset time. Therefore, a strong vertical electric field is first formed between the first common electrode 111 and the first pixel electrodes 121, and then the vertical electric field slowly disappears, causing all the cholesteric liquid crystal molecules to first rotate to the H state, and then rotate and remain stationary in the FC state, allowing light to pass through the bistable liquid crystal cell 10. Of course, it is also possible to control all the cholesteric liquid crystal molecules to be in the H state. A common voltage signal Vcom is applied to the second common electrode 321, and a corresponding grayscale voltage is applied to the second pixel electrode 322. A voltage difference is formed between the second pixel electrode 322 and the second common electrode 321, generating a horizontal electric field. Figure 16 E1) causes positive liquid crystal molecules to deflect in the horizontal direction in a direction parallel to the horizontal electric field. The gray level voltage includes gray level voltages from 0 to 255. When different gray level voltages are applied to the second pixel electrode 322, the corresponding second pixel unit P2 presents different brightness, thereby displaying different images to achieve normal display in transmission mode.

[0060] In both reflection and transmission modes, the pressure detection unit 20 operates normally and monitors the real-time pressure value borne by the display device. When the real-time pressure value is greater than or equal to the preset pressure value, it controls the bistable liquid crystal cell 10 to refresh the currently displayed same image.

[0061] [Example 2] Figure 17 This is a schematic diagram of the display device in its initial state according to Embodiment 2 of the present invention. Figure 18 This is a schematic diagram showing the distribution of the pressure detection unit on the display device in Embodiment 2 of the present invention. Figure 17 and Figure 18 As shown, the display device and control method provided in Embodiment 2 of the present invention are the same as those in Embodiment 1. Figures 6 to 16 The display devices and control methods in the two are basically the same, the difference being: In this embodiment, the pressure detection unit 20 is a capacitive pressure sensor. The capacitive pressure sensor includes a first electrode 21, a dielectric layer 22, and a second electrode 23 stacked sequentially. Both the first electrode 21 and the second electrode 23 are annular structures arranged around the periphery of the display area 110, thereby avoiding affecting the transmittance. Optionally, a conductive material (e.g., ITO, copper, aluminum, etc.) film is deposited on the side of the first array substrate 12 away from the bistable liquid crystal layer 13 using a masking process, and then etched to form the first electrode 21; similarly, a conductive material (e.g., ITO, copper, aluminum, etc.) film is deposited on the side of the second polarizer 42 away from the liquid crystal layer 33, and then etched to form the second electrode 23. The bistable liquid crystal cell 10 and the transmissive display liquid crystal cell 30 are bonded together with an adhesive (e.g., OCA adhesive), and the first electrode 21 and the second electrode 23 form a parallel plate capacitor architecture. The adhesive serves as the dielectric layer 22 of the capacitive pressure sensor.

[0062] Figure 19 This is a schematic diagram of the pressure detection unit after it is pressed in Embodiment 2 of the present invention. Figure 20 This is a graph showing the relationship between the capacitance value and pressure of the pressure detection unit in Embodiment 2 of the present invention. Figure 19 and Figure 20 As shown, the detection principle is as follows: 1. When an object (finger) presses the display device, the dielectric layer 22 between the first electrode 21 and the second electrode 23 deforms, and the gap in the pressing area changes from d1 to d2; 2. The sensing capacitance of a capacitive pressure sensor is C = ε0 * ε A / d, and F=K / d, d changes, thus the relationship between pressure F and capacitance C can be detected, where ε0 is the vacuum permittivity, ε is the relative permittivity (determined by the dielectric material), A is the effective area of ​​the plates, d is the distance between the plates, and K is the deformation coefficient.

[0063] 3. When the pressure (F) reaches a certain value Fth, the bistable liquid crystal molecules undergo a phase transition, and the display image is abnormal. The capacitance at this time is recorded as Cth. When C > Cth, wait for the pressure to disappear, and the processor immediately provides a reset signal (Reset) to the driver of the bistable liquid crystal cell 10 to refresh the correct image and avoid affecting the image quality due to pressing.

[0064] Those skilled in the art should understand that the remaining structures and working principles of this embodiment are the same as those of Embodiment 1, and will not be repeated here.

[0065] [Example 3] Figure 21 This is a schematic diagram of the display device in its initial state according to Embodiment 3 of the present invention. The display device and control method provided in Embodiment 3 of the present invention are the same as those in Embodiment 1.Figures 6 to 16 Example 2 Figures 17 to 20 The display devices and control methods in the two are basically the same, the difference being: In this embodiment, the display device includes a bistable liquid crystal cell 10 and a pressure detection unit 20, eliminating the need for a transmissive display liquid crystal cell 30 and a backlight module 50, thus achieving single-cell display and reducing the cell thickness of the display device. The bistable liquid crystal cell 10 controls the image display in reflective mode, and the pressure detection unit 20 detects the real-time pressure value experienced by the display device. Therefore, the display device can achieve reflective display through the bistable liquid crystal cell 10, but cannot achieve transmissive display.

[0066] Furthermore, the pressure detection unit 20 is disposed between the opposing substrate 11 and the first array substrate 12. For example, the pressure detection unit 20 can be disposed at the sealant between the opposing substrate 11 and the first array substrate 12.

[0067] Optionally, a light-absorbing layer 122 is further provided on the side of the first array substrate 12 away from the bistable liquid crystal layer 13. The light-absorbing layer 122 is used to absorb light passing through the bistable liquid crystal cell 10, thereby making the display device darker in black and improving contrast. Optionally, the light-absorbing layer 122 uses black ink with an L value (representing brightness) greater than 25 and an OD value (optical density) greater than 4, thus giving the light-absorbing layer 122 characteristics such as high blackness and good gloss, ensuring a darker black image. Of course, the light-absorbing layer 122 can be made of BM material.

[0068] Those skilled in the art should understand that the remaining structures and working principles of this embodiment are the same as those of Embodiment 1 and Embodiment 2, and will not be repeated here.

[0069] In this document, the directional terms such as up, down, left, right, front, and back are defined according to the position of the structures in the accompanying drawings and the relative positions of the structures, and are only used for clarity and convenience in expressing the technical solution. It should be understood that the use of these directional terms should not limit the scope of protection claimed in this application. It should also be understood that the terms "first" and "second," etc., used herein are only used for distinction in name and are not used to limit the number or order.

[0070] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content without departing from the scope of the technical solution of the present invention, which are equivalent embodiments with equivalent changes. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the technical solution of the present invention shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. A display device, characterized in that, include: A bistable liquid crystal cell (10) and a pressure detection unit (20) are provided. The bistable liquid crystal cell (10) is used to control the display screen in reflective mode, and the pressure detection unit (20) is used to detect the real-time pressure value borne by the display device. When the real-time pressure value of the display device is detected to be greater than or equal to the preset pressure value, the bistable liquid crystal cell (10) is controlled to refresh the currently displayed same screen.

2. The display device according to claim 1, characterized in that, The bistable liquid crystal cell (10) includes an opposing substrate (11), a first array substrate (12) disposed opposite to the opposing substrate (11), and a bistable liquid crystal layer (13) located between the opposing substrate (11) and the first array substrate (12). The opposing substrate (11) is provided with a first common electrode (111), and the first array substrate (12) is provided with a first pixel electrode (121) cooperating with the first common electrode (111). The pressure detection unit (20) is disposed between the opposing substrate (11) and the first array substrate (12).

3. The display device according to claim 1, characterized in that, The display device includes a transmissive liquid crystal cell (30) and a backlight module (50). The bistable liquid crystal cell (10), the transmissive liquid crystal cell (30), and the backlight module (50) are stacked sequentially. The transmissive liquid crystal cell (30) is used to control the display of the screen in transmissive mode.

4. The display device according to claim 3, characterized in that, The pressure detection unit (20) is located between the bistable liquid crystal cell (10) and the transmissive display liquid crystal cell (30).

5. The display device according to any one of claims 1-4, characterized in that, The pressure detection unit (20) includes a strain gauge pressure sensor, a piezoresistive pressure sensor, a capacitive pressure sensor, or a piezoelectric pressure sensor.

6. The display device according to claim 5, characterized in that, The display device has a display area (110) and a non-display area (120) located around the periphery of the display area (110), and the pressure detection unit (20) is located in the non-display area (120).

7. The display device and control method according to claim 6, characterized in that, The pressure detection unit (20) is located near the top corner of the non-display area (120), and / or the pressure detection unit (20) is located in the middle area near the edge of the non-display area (120).

8. The display device and control method according to claim 6, characterized in that, The capacitive pressure sensor includes a first electrode (21), a dielectric layer (22), and a second electrode (23) stacked in sequence. Both the first electrode (21) and the second electrode (23) are annular structures arranged around the periphery of the display area (110).

9. A control method for a display device, characterized in that, The control method for controlling the display device as described in any one of claims 1-8 includes: Detect the real-time pressure value experienced by the display device; The real-time pressure value is compared with the preset pressure value. When the real-time pressure value is greater than or equal to the preset pressure value, the bistable liquid crystal cell (10) is controlled to refresh the currently displayed same screen; when the real-time pressure value is less than the preset pressure value, the bistable liquid crystal cell (10) is controlled to maintain the currently displayed screen.

10. The control method for the display device according to claim 9, characterized in that, The display device includes a transmissive liquid crystal cell (30) and a backlight module (50), wherein the bistable liquid crystal cell (10), the transmissive liquid crystal cell (30) and the backlight module (50) are stacked sequentially. In reflection mode, both the transmissive display liquid crystal cell (30) and the backlight module (50) are controlled to be in the off state, and the bistable liquid crystal cell (10) is controlled to display the image; In the transmission mode, both the transmission display liquid crystal cell (30) and the backlight module (50) are controlled to be in the open state, the entire surface of the bistable liquid crystal cell (10) is controlled to be in a fog or transparent state, and the transmission display liquid crystal cell (30) is controlled to display the image.

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