Patent Publication Number: US-2023134866-A1

Title: Liquid crystal handwriting board, handwriting device, and method for controlling handwriting device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a U.S. national stage of international application No. PCT/CN2021/123853, filed on Oct. 14, 2021, which claims priority to Chinese Patent Application No. 202011293671.3 filed on Nov. 18, 2020 and entitled “LIQUID CRYSTAL HANDWRITING PAD HANDWRITING DEVICE, AND METHOD FOR CONTROLLING HANDWRITING DEVICE,” and the disclosures of which are herein incorporated by references in their entireties. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to the field of display technologies, and in particular, relates to a liquid crystal handwriting board, a handwriting board device, and a method for controlling a handwriting board device. 
     BACKGROUND 
     A handwriting board is an electronic device for achieving word writing and drawing. A liquid crystal handwriting board has a less power consumption and clear writing, and thus occupies a greater market share in recent years. However, the present liquid crystal handwriting board merely achieves entire plane erasing, and has a poor flexibility. 
     SUMMARY 
     Embodiments of the present disclosure provide a liquid crystal handwriting board, a handwriting board device, and a method for controlling a handwriting board device. The technical solutions are as follows. 
     According to some embodiments of the present disclosure, a liquid crystal handwriting board is provided. The liquid crystal handwriting board includes: 
     a liquid crystal panel, and a drive assembly electrically connected to the liquid crystal panel; wherein 
     the liquid crystal panel includes: a first substrate and a second substrate that are opposite to each other, and a liquid crystal layer disposed between the first substrate and the second substrate, wherein the first substrate includes a plurality of bulk pixel electrodes, and the second substrate includes a planar common electrode; and 
     the drive assembly is configured to apply, based on position information of a region to be erased, a pixel voltage to a pixel electrode in the region to be erased in the case that the liquid crystal handwriting board is in an erasing mode, such that a voltage difference is developed between the pixel electrode in the region to be erased and the common electrode. 
     In some embodiments, the first substrate further includes: a plurality of thin-film transistors electrically connected to the drive assembly, wherein the pixel electrode is electrically connected to at least one of the plurality of thin-film transistors. 
     In some embodiments, the thin-film transistor includes: a first electrode and a second electrode, wherein the first electrode includes a U-shaped structure, the second electrode includes a strip-shaped structure, one end of the second electrode is disposed within the U-shaped structure, and the other end of the second electrode is electrically connected to the pixel electrode. 
     In some embodiments, the first substrate further includes: a first base, wherein both the thin-film transistor and the pixel electrode are disposed on the first base; and 
     the thin-film transistor further includes: a gate, an active layer pattern, and a gate insulation layer, 
     wherein the gate is disposed on a side, proximal to the first base, of the active layer pattern, the gate insulation layer is disposed between the gate and the active layer pattern, both the first electrode and the second electrode are disposed on a side, distal from the first base, of the active layer pattern, and both the first electrode and the second electrode are in contact with the active layer pattern. 
     In some embodiments, the first substrate further includes: a data line and a gate line that are disposed on the first base and provided with extension directions intersected with each other, wherein the data line is electrically connected to the first electrode, the gate line is electrically connected to the gate, and both the data line and the gate line are electrically connected to the drive assembly. 
     In some embodiments, the first substrate further includes a secondary electrode line disposed on the first base and in a same layer as the gate line, wherein an extension direction of the secondary electrode line is consistent with the extension direction of the gate line. 
     In some embodiments, the first substrate further includes: a first planarization layer disposed on the thin-film transistor, wherein the pixel electrode is disposed on the first planarization layer and is in contact with the first planarization layer, a via hole is disposed in the first planarization layer, and the pixel electrode is electrically connected to the second electrode via the via hole. 
     In some embodiments, the first substrate further includes a second planarization layer disposed on the pixel electrode. 
     In some embodiments, the liquid crystal panel further includes a spacer disposed between the first substrate and the second substrate. 
     In some embodiments, the liquid crystal layer includes bistable liquid crystal molecules. 
     According to some embodiments of the present disclosure, a handwriting board device is provided. The handwriting board device includes: 
     above liquid crystal handwriting board, and a position determination assembly electrically connected to a drive assembly in the liquid crystal handwriting board; 
     wherein the position determination assembly is configured to acquire position information of a region to be erased in a liquid crystal panel in the liquid crystal handwriting board, and send the position information of the region to be erased to the drive assembly. 
     In some embodiments, the handwriting board device further includes a toggling switch electrically connected to the position determination assembly; wherein the toggling switch is configured to control switching of the liquid crystal handwriting board between an erasing mode and a writing mode; and 
     the position determination assembly is further configured to stop acquiring the position information of the region to be erased in the liquid crystal panel in the case that the liquid crystal handwriting board is in the writing mode. 
     In some embodiments, the position determination assembly includes an infrared sensor. 
     According to some embodiments of the present disclosure, a method for controlling a handwriting board device is provided. The method is applicable to the handwriting board device according to any one of above embodiments, and includes: 
     acquiring, in the case that liquid crystal handwriting board is in an erasing mode, position information of a region to be erased in a liquid crystal panel in the liquid crystal handwriting board by a position determination assembly, and sending the position information of the region to be erased to a drive assembly; and 
     applying, based on the position information of the region to be erased, a pixel voltage to a pixel electrode in the region to be erased by the drive assembly, such that a voltage difference is developed between the pixel electrode in the region to be erased and a common electrode. 
     In some embodiments, the method further includes: controlling the position determination assembly to stop acquiring the position information of the region to be erased in the liquid crystal panel in the case that the liquid crystal handwriting board is in a writing mode. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For clearer descriptions of the technical solutions in the embodiments of the present disclosure, the following briefly introduces the accompanying drawings required for describing the embodiments. Apparently, the accompanying drawings in the following description show merely some embodiments of the present disclosure, and a person of ordinary skill in the art still derives other drawings from these accompanying drawings without creative efforts. 
         FIG.  1    is a structural diagram of film layers of a liquid crystal handwriting board known to the inventors; 
         FIG.  2    is a schematic structural diagram of a liquid crystal handwriting board according to some embodiments of the present disclosure; 
         FIG.  3    is a schematic structural diagram of film layers of a liquid crystal panel in a liquid crystal handwriting board according to some embodiments of the present disclosure; 
         FIG.  4    is a top view of the liquid crystal panel in the liquid crystal handwriting board shown in  FIG.  3    at a thin-film transistor region; 
         FIG.  5    is a top view of the liquid crystal panel in the liquid crystal handwriting board shown in  FIG.  3   ; 
         FIG.  6    is a schematic structural diagram of film layers of another liquid crystal panel in a liquid crystal handwriting board according to some embodiments of the present disclosure; 
         FIG.  7    is a top view of the liquid crystal panel in the liquid crystal handwriting board shown in  FIG.  6   ; 
         FIG.  8    is a schematic structural diagram of film layers of another liquid crystal panel in a liquid crystal handwriting board according to some embodiments of the present disclosure; 
         FIG.  9    is a schematic structural diagram of a handwriting board device according to some embodiments of the present disclosure; and 
         FIG.  10    is a flowchart of a method for controlling a handwriting board device according to some embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     For clearer descriptions of the objectives, technical solutions, and advantages in the present disclosure, the embodiments of the present disclosure are described in detail hereinafter in combination with the accompanying drawings. 
     Referring to  FIG.  1   ,  FIG.  1    is a structural diagram of film layers of a liquid crystal handwriting board known to the inventors. The liquid crystal handwriting board  00  generally includes: a first substrate  01  and a second substrate  02  that are opposite to each other, and a liquid crystal layer  03  disposed between the first substrate  01  and the second substrate  02 . A planar electrode  011  is disposed on a side, proximal to the second substrate  03 , of the first substrate  01 , and a planar electrode  021  is disposed on a side, proximal to the first substrate  01 , of the second substrate  02 . Both the planar electrode  011  and the planar electrode  021  are entire plane electrodes. 
     In the case that the liquid crystal handwriting board  00  is in a writing mode, a part of liquid crystal molecules in the liquid crystal layer  03  reflect visible light under an action of an external pressure, and the liquid crystal handwriting board  00  displays a handwriting. In the case that the liquid crystal handwriting board  00  is in an erasing mode, the liquid crystal handwriting board  00  applies a voltage to the planar electrode  011  and the planar electrode  021  that are respectively disposed on two sides of the liquid crystal layer  03 , such that a voltage difference is developed between the planar electrode  011  and the planar electrode  021 , and the liquid crystal molecules in the liquid crystal layer  03  rearrange under the action of the voltage difference to erase the handwriting displayed on the liquid crystal handwriting board. 
     However, as both the planar electrode  011  in the first substrate  01  and the planar electrode  021  in the second substrate  02  are entire plane electrodes, all liquid crystal molecules in the liquid crystal layer  03  rearrange under the action of the voltage difference between the planar electrode  011  and the planar electrode  021  in the case that the liquid crystal handwriting board  00  is in the erasing mode, such that the liquid crystal handwriting board  00  merely achieves entire plane erasing, and the flexibility in use is poor. 
     Referring to  FIG.  2   ,  FIG.  2    is a schematic structural diagram of a liquid crystal handwriting board according to some embodiments of the present disclosure. The liquid crystal handwriting board  000  includes: 
     a liquid crystal panel  001  and a drive assembly  002 . 
     The liquid crystal panel  001  includes: a first substrate  100  and a second substrate  200  that are opposite to each other, and a liquid crystal layer  300  disposed between the first substrate  100  and the second substrate  200 . The first substrate  100  includes a plurality of bulk pixel electrodes  101 , and the second substrate  200  includes a planar common electrode  201 . In some embodiments, the plurality of bulk pixel electrodes  101  are arranged in a matrix, and an orthogonal projection of the common electrode  201  on the first substrate  100  covers a region of the plurality of bulk pixel electrodes  101 . 
     The drive assembly  002  is electrically connected to the liquid crystal panel  001 , and is configured to apply, based on position information of a region to be erased, a pixel voltage to a pixel electrode  101  in the region to be erased in the case that the liquid crystal handwriting board  000  is in an erasing mode, such that a voltage difference is developed between the pixel electrode  101  in the region to be erased and the common electrode  201 . 
     In summary, the liquid crystal handwriting board in the embodiments of the present disclosure includes: a liquid crystal panel and a drive assembly. The liquid crystal panel includes: a first substrate and a second substrate that are opposite to each other, and a liquid crystal layer disposed between the first substrate and the second substrate. As the pixel electrodes in the first substrate in the liquid crystal panel are a plurality of bulk electrodes, the drive assembly electrically connected to the liquid crystal panel applies, based on position information of a region to be erased, a pixel voltage to a pixel electrode in the region to be erased in the case that the liquid crystal handwriting board is in an erasing mode, such that a voltage difference is developed between the pixel electrode in the region to be erased and the common electrode. Thus, the liquid crystal molecules in the region to be erased in the liquid crystal layer rearrange under the action of the voltage difference. As such, a local region of the liquid crystal handwriting board is erased, and the flexibility of the liquid crystal handwriting board in use is improved. 
     In other way, in the case that the liquid crystal handwriting board is in the erasing mode, the liquid crystal handwriting board needs to apply a voltage to two inner planar electrodes. As both the two planar electrodes are entire planar electrodes, the liquid crystal handwriting board applies the voltage to the entire planar electrodes by enlarging a drive voltage, such that a power consumption of the liquid crystal handwriting board is increased, and a use life of the liquid crystal handwriting board is reduced. 
     In the present disclosure, referring to  FIG.  3   ,  FIG.  3    is a schematic structural diagram of film layers of a liquid crystal panel in a liquid crystal handwriting board according to some embodiments of the present disclosure. The first substrate  100  in the liquid crystal panel  001  further includes a plurality of thin-film transistors  102  (TFT) electrically connected to the drive assembly  002 . Each pixel electrode  101  is electrically connected to at least one of the plurality of thin-film transistors  102 . As such, the drive assembly  002  selectively applies a pixel voltage to the pixel electrodes  101  in the liquid crystal panel  001  through the plurality of thin-film transistors  102 , so as to apply the pixel voltage to the pixel electrodes  101  in part of regions in the liquid crystal panel  001 , and erase the local region of the liquid crystal handwriting board  000  in the erasing mode. In addition, in the case that the liquid crystal handwriting board  000  is in the erasing mode, it is not necessary to apply the pixel voltage to all pixel electrodes  101  in the liquid crystal panel  001 , and the pixel voltage applied to each pixel electrode  101  is generally less. Thus, the power consumption of the liquid crystal handwriting board  000  is efficiently reduced, and the use life of the liquid crystal handwriting board  000  is prolonged. 
     In some embodiments, referring to  FIG.  3    and  FIG.  4   ,  FIG.  4    is a top view of the liquid crystal panel in the liquid crystal handwriting board shown in  FIG.  3    at a thin-film transistor region. The thin-film transistor  102  includes a first electrode  102   a  and a second electrode  102   b . The first electrode  102   a  is one of a source and a drain, and the second electrode  102   b  is the other of the source and the drain. The first electrode  102   a  includes a U-shaped structure, and the second electrode  102   b  includes a strip-shaped structure. One end of the second electrode  102   b  is disposed within the U-shaped structure in the first electrode  102   a,  and the other end of the second electrode  102   b  is electrically connected to the pixel electrode  101 . 
     In some embodiments, as shown in  FIG.  4   , the first electrode  102   a  includes a first extension portion A, a second extension portion B, and a third extension portion C that are sequentially connected. An extension direction of the first extension portion A of the first electrode  102   a  is consistent with the extension direction of the third extension portion C of the first electrode  102   a,  and an extension direction of the second extension portion B of the first electrode  102   a  is perpendicular to the extension direction of the first extension portion A of the first electrode  102   a  and the extension direction of the third extension portion C of the first electrode  102   a.  As such, the first extension portion A, the second extension portion B, and the third extension portion C that are sequentially connected form the U-shaped structure of the first electrode  102   a.    
     The second electrode  102   b  includes: a first connection portion D disposed between the first extension portion A of the first electrode  102   a  and the third extension portion C of the first electrode  102   a,  and a second connection portion E connected to the first connection portion D. The first connection portion D of the second electrode  102   b  is the strip-shaped structure in the second electrode  102   b,  and the second connection portion E of the second electrode  102   b  is in a bulk-shaped structure and is electrically connected to the pixel electrode  101 . 
     In the embodiments of the present disclosure, as shown in  FIG.  3    and  FIG.  4   , the thin-film transistor  102  further includes an active layer pattern  102   c  in contact with the first electrode  102   a  and the second electrode  102   b.  In the case that the first electrode  102   a  in the thin-film transistor  102  includes the U-shaped structure, and the second electrode  102   b  in the thin-film transistor  102  includes the strip-shaped structure with one end extending to the U-shaped structure, a channel region F of the active layer pattern  102   c  is a U-shaped channel region. It is noted that, the channel region F of the active layer pattern  102   c  refers to a region in the active layer pattern  102   c  where the active layer pattern  102   c  is in contact with the first electrode  102   a , and a region between regions where the active layer pattern  102   c  is in contact with the second electrode  102   b.    
     In the case that the channel region F of the active layer pattern  102   c  in the thin-film transistor  102  is the U-shaped channel region, the thin-film transistor  102  withstands a higher breakdown voltage due to a larger aspect ratio of the U-shaped channel region, such that the use life of the liquid crystal handwriting board  000  is further prolonged. 
     In some embodiments, the channel region F of the active layer pattern  102   c  includes two first strip regions with the same extension direction and the same length, and two second strip regions configured to connect the two first strip regions. A width of the first strip region is equal to a width of the second strip region. In the present disclosure, a length of the channel region F of the active layer pattern  102   c  is a sum of the lengths of the two first strip regions, and a width of the channel region F is a sum of the width of the first strip region and the width of the second strip region. 
     In some embodiments, an aspect ratio of the channel region F of the active layer pattern  102   c  is 50/4 μm. As such, the thin-film transistor  102  meets a current required to drive the pixel, and withstands the higher breakdown voltage. 
     In the embodiments of the present disclosure, referring to  FIG.  3   , the first substrate  100  further includes a first base  103 . Both the thin-film transistor  102  and the pixel electrode  101  are disposed on the first base  103 . The thin-film transistor  102  further includes: a gate  102   d  and a gate insulation layer  102   e.  The gate  102   d  is disposed on a side, proximal to the first base  103 , of the active layer pattern  102   c,  and the gate insulation layer  102   e  is disposed between the gate  102   d  and the active layer pattern  102   c.  Both the first electrode  102   a  and the second electrode  102   b  are disposed on a side, distal from the first base  103 , of the active layer pattern  102   c,  and both the first electrode  102   a  and the second electrode  102   b  are in contact with the active layer pattern  102   c.  That is, the thin-film transistor  102  is a bottom-gate thin-film transistor. In some embodiments, the thin-film transistor  102  is a top-gate thin-film transistor, which is not limited in the embodiments of the present disclosure. 
     In some embodiments, the first base  103  is a glass base. 
     In the present disclosure, as shown in  FIG.  3    and  FIG.  5   ,  FIG.  5    is a top view of the liquid crystal panel in the liquid crystal handwriting board shown in  FIG.  3   . The first substrate  100  further includes a data line  104  and a gate line  105  that are disposed on the first base  103  and provided with extension directions intersected with each other. The data line  104  and the gate line  105  provided with extension directions intersected with each other define a plurality of pixel regions  001   a  in the liquid crystal panel  001 . In some embodiments, any two adjacent data lines  104  and any two adjacent gate lines  105  form a pixel region  001   a.  Each pixel electrode  101  in the first substrate  100  is disposed in one pixel region  001   a.    
     In some embodiments, the pixel region  001   a  is a rectangle region with a length and a width being 1 mm. As such, a dizzy sense of a user in viewing the liquid crystal panel is reduced, and a greater resolution of the liquid crystal panel  001  is ensured. In the case that the resolution of the liquid crystal panel  001  is greater, an area of a minimum erasable region (that is, the pixel region) of the liquid crystal handwriting board  000  is less, and thus a precision of erasing the liquid crystal handwriting board  000  is efficiently improved. 
     In the embodiments of the present disclosure, the data line  104  is electrically connected to the first electrode  102   a  in the thin-film transistors  102 , and the gate line  105  is electrically connected to the gate  102   d  in the thin-film transistors  102 . In some embodiments, the data line  104  is disposed in a same layer as the first electrode  102   a  and the second electrode  102   b.  That is, the data line  104 , the first electrode  102   a,  and the second electrode  102   b  are formed by one pattern process. The gate line  105  is disposed in the same layer as the gate  102   d.  That is, the gate line  105  and the gate  102   d  are formed by one pattern process. 
     In some embodiments, a thickness between the data line  104  and the first electrode  102   a  and a thickness between the gate line  105  and the gate  102   d  range from 350 nm to 450 nm. In some embodiments, both the thickness between the data line  104  and the first electrode  102   a  and the thickness between the gate line  105  and the gate  102   d  are 400 nm. Both a material of the data line  104  and a material of the gate line  105  include metal materials, such as, aluminum, molybdenum, an alloy, or the like. As such, resistances of the data line  104  and the gate line  105  are reduced. 
     In the embodiments of the present disclosure, both the data line  104  and the gate line  105  are further electrically connected to the drive assembly  002 . The drive assembly  002  includes a timing controller (TCON), a source driver, and a gate driver. In some embodiments, the timing controller is electrically connected to the source driver and the gate driver, the data line  104  in the liquid crystal panel  001  is electrically connected to the source driver, and the gate line  105  in the liquid crystal panel  001  is electrically connected to the gate driver. 
     A main function of the timing controller is to process the position information of the region to be erased, so as to determine positions of the pixel electrodes in the region to be erased, and generate corresponding data signals and control signals. The data signal is sent to the source driver, the source driver converts the received data signal to a pixel voltage, and the pixel voltage is written to a corresponding pixel region in the liquid crystal panel  001  through the data line  104 . The control signal is sent to the gate driver, the gate driver converts the received control signal to a gate voltage, and the gate voltage is written to a corresponding pixel region in the liquid crystal panel  001  through the gate line  105 . Thus, independent control over one pixel in the liquid crystal panel  001  is achieved. 
     In some embodiments, a width of the data line  104  and a width of the gate line  105  ranges from 8 μm to 12 μm. In some embodiments, both the width of the data line  104  and the width of the gate line  105  are 10 μm. As such, the resistances of the data line  104  and the gate line  105  are further reduced, a possibility of visible grid lines in the liquid crystal panel  001  due to reflection of the data line  104  and the gate line  105  is reduced, and a display effect of the liquid crystal handwriting board  000  is improved. 
     In some embodiments, pitches between the plurality of bulk pixel electrodes  101  range from 18 μm to 22 μm. In some embodiments, the pitches between the plurality of bulk pixel electrodes  101  are 20 μm. As such, pitches between the pixel electrode  101 , and the data line  104  and gate line  105  are greater, and parasitical capacitors between the pixel electrode  101 , and the data line  104  and gate line  105  are reduced. 
     In the embodiments of the present disclosure, referring to  FIG.  6    and  FIG.  7   ,  FIG.  6    is a schematic structural diagram of film layers of another liquid crystal panel in a liquid crystal handwriting board according to some embodiments of the present disclosure, and  FIG.  7    is a top view of the liquid crystal panel in the liquid crystal handwriting board shown in  FIG.  6   . The first substrate  100  further includes: a secondary electrode line  106  disposed on the first base  103  and in the same layer as the gate line  105 . An extension direction of the secondary electrode line  106  is consistent with an extension direction of the gate line  105 . 
     In some embodiments, the pixel electrodes  101  in the first substrate  100  are arranged in multiple rows, and a number of the secondary electrode lines  106  is equal to a number of rows of the pixel electrodes  101 . An orthogonal projection of each secondary electrode line  106  on the first base  103  is overlapped with an orthogonal projection of a corresponding row of the pixel electrodes  101  on the first base  103 , and the secondary electrode line  106  and each pixel electrode  101  in the corresponding row of the pixel electrodes  101  form a storage capacitor. The storage capacitor is configured to hold a charging voltage of the pixel electrode  101 . Furthermore, the storage capacitor prevents a change of a voltage of the pixel region  001   a  being erased from affecting a voltage of surrounded pixel regions  001   a,  and thus, an effect on the display effect of the surrounded pixel regions  001   a  is avoided. 
     In some embodiments, referring to  FIG.  3    and  FIG.  6   , the first substrate  100  further includes a first planarization layer  107  disposed on the thin-film transistor  102 . The pixel electrode  101  is disposed on the first planarization layer  107  and is in contact with the first planarization layer  107 , and a via hole a is disposed in the first planarization layer  107 . The pixel electrode  101  is electrically connected to the second electrode  102   b  via the via hole a. The first planarization layer  107  is configured to protect the thin-film transistor  102 . 
     In the embodiments of the present disclosure, referring to  FIG.  8   ,  FIG.  8    is a schematic structural diagram of film layers of another liquid crystal panel in a liquid crystal handwriting board according to some embodiments of the present disclosure. The first substrate  100  further includes a second planarization layer  108  disposed on the pixel electrode  101 . In the case that the first substrate  100  and the second substrate  200  are opposite to each other, a foreign material is present between the first substrate  100  and the second substrate  200  due to a dusty facility environment. The second planarization layer  108  is configured to avoid the foreign material between the first substrate  100  and the second substrate  200 , and conduct the pixel electrode  101  in the first substrate  100  and the common electrode  201  in the second substrate  200 . 
     In the embodiments of the present disclosure, referring to  FIG.  3   ,  FIG.  6   , and  FIG.  8   , the liquid crystal panel  001  further includes a spacer  400  disposed between the first substrate  100  and the second substrate  200 . The spacer  400  is configured to separate the first substrate  100  from the second substrate  200 , and the spacer  400  provides, due to an elasticity, an elastic deformation in the case that the liquid crystal handwriting board  000  experiences an external pressure. In addition, the spacer  400  functions as a support for the liquid crystal layer  300 , such that an effect on an arrangement manner of the liquid crystal molecules in the liquid crystal layer  300  is avoided in the case that the liquid crystal panel  001  is pressed, and the display effect of the liquid crystal handwriting board  000  is improved. 
     In the embodiments of the present disclosure, the liquid crystal layer  300  includes bistable liquid crystal molecules. The bistable liquid crystal molecule has a planar texture status (a P status), a focal conic texture status (a FC status), and a hometropic texture status (a H status). The P status and the FC status are steady statuses, and are held without the voltage. The H status is a non-steady status, and is present in sustained applying of voltage. In the case that the liquid crystal handwriting board  000  experiences the external pressure, the bistable liquid crystal molecules in the liquid crystal layer  300  are converted to the P status under the action of the external pressure and reflect the visible light, and thus a region experiencing the external pressure in the liquid crystal panel  001  displays the handwriting. In the case that the drive assembly  002  in the liquid crystal handwriting board  000  applies the pixel voltage to the pixel electrode  101  in the region to be erased, a voltage difference is developed between the pixel electrode  101  in the region to be erased and the common electrode  201 . The bistable liquid crystal molecules in the region to be erased are rearranged as the FC status under the action of the voltage difference, and does not reflect the visible light. In this case, the handwriting in the region to be erased is erased. 
     In the embodiments of the present disclosure, as shown in  FIG.  3   ,  FIG.  6   , and  FIG.  8   , the second substrate  200  further includes a second base  202 . The second base  202  is a flexible base, and a material of the second base  202  includes polyethylene terephthalate (PET). The common electrode  201  is disposed on the second base  202 . 
     In summary, the liquid crystal handwriting board in the embodiments of the present disclosure includes: a liquid crystal panel and a drive assembly. The liquid crystal panel includes: a first substrate and a second substrate that are opposite to each other, and a liquid crystal layer disposed between the first substrate and the second substrate. As the pixel electrodes in the first substrate in the liquid crystal panel are a plurality of bulk electrodes, the drive assembly electrically connected to the liquid crystal panel applies, based on position information of a region to be erased, a pixel voltage to a pixel electrode in the region to be erased in the case that the liquid crystal handwriting board is in an erasing mode, such that a voltage difference is developed between the pixel electrode in the region to be erased and the common electrode. Thus, the liquid crystal molecules in the region to be erased in the liquid crystal layer rearrange under the action of the voltage difference. As such, a local region of the liquid crystal handwriting board is erased, and the flexibility of the liquid crystal handwriting board in use is improved. 
     A method for manufacturing a liquid crystal panel is further provided. The method for manufacturing the liquid crystal panel is used to manufacture the liquid crystal panel shown in  FIG.  8   . The method for manufacturing the liquid crystal panel includes the following steps. 
     In step A1, a first substrate is acquired by forming a gate pattern, a gate insulation layer, an active layer pattern, a source and drain pattern, a first planarization layer, a pixel electrode, and a second planarization layer on a first base. 
     In some embodiments, a gate layer is formed on the first base, and the gate pattern is formed by performing one pattern process on the gate layer. The gate pattern includes a gate, and a gate line and a secondary electrode line that are connected to the gate. In some embodiments, the first base is a glass base. A material of the gate pattern includes a metal material, such as, aluminum, molybdenum, an alloy, or the like. The gate line is used to apply a gate voltage to the gate. 
     Then, the gate insulation layer is formed on the first base with the gate pattern. The gate insulation layer is used to protect the gate line. In some embodiments, a material of the gate insulation layer includes a silicon dioxide, a silicon nitride, or a mixture of the silicon dioxide and the silicon nitride. 
     Then, an active material thin film is formed on the first base with the gate insulation layer, and the active layer pattern is formed by performing the one pattern process on the active material thin film. In some embodiments, a material of the active layer pattern includes polycrystalline silicon, amorphous silicon, or a semiconductor material such as an oxide semiconductor. 
     Then, a source and drain material layer is formed on the first base with the active layer pattern, and the source and drain pattern is formed by performing the one pattern process on the source and drain material layer. The source and drain pattern includes a first electrode, a second electrode, and a data line. The first electrode is one of a source and a drain, and the second electrode is the other of the source and the drain. In some embodiments, a material of the source and drain pattern includes aluminum. 
     Then, a planarization thin film is formed on the first base with the source and drain pattern, and the first planarization layer is formed by performing the one pattern process on the planarization thin film. The first planarization layer is used to protect the thin-film transistor. A via hole is disposed in the first planarization layer, and the subsequently formed pixel electrode is electrically connected to the second electrode via the via hole. In some embodiments, a material of the first planarization layer includes a silicon dioxide, a silicon nitride, or a mixture of the silicon dioxide and the silicon nitride. 
     Then, a first conductive thin film is formed on the first base with the first planarization layer, and a plurality of bulk pixel electrodes are formed by performing the one pattern process on the first conductive thin film. In some embodiments, materials of the plurality of pixel electrodes include transparent conductive materials, such as an indium tin oxide (ITO), an indium zinc oxide (IZO), or the like. 
     Eventually, a planarization thin film is formed on the first base with the pixel electrode, and a second planarization layer is formed by performing the one pattern process on the planarization thin film. 
     It is noted that the first substrate is formed by above processes. In some embodiments, it is further noted that the one pattern process in above embodiments includes: photoresist coating, exposing, developing, etching, and photoresist removing. 
     In some embodiments, in above processes, the two patterning processes of forming the active layer pattern and the source and drain pattern are combined to one pattern process by a halftone mask. 
     In step A2, a spacer and a sealant are formed on the first substrate. 
     In some embodiments, an organic thin film is formed on the second planarization layer in the first substrate, and the spacer is formed by performing the one pattern process on the organic thin film. 
     Then, the sealant is formed by coating a sealant material in a periphery of the first substrate with the spacer. 
     It is noted that in some embodiments, the one pattern process in above embodiments includes: photoresist coating, exposing, developing, etching, and photoresist removing. 
     In step A3, a second substrate is acquired by forming a common electrode on a second base. 
     In some embodiments, a second conductive thin film is formed on the second base, and the common electrode is formed by performing the one pattern process on the second conductive thin film. 
     In some embodiments, the second base is a flexible base, and a material of the second base includes PET. The common electrode is a plane electrode, and a material of the common electrode includes ITO or IZO. 
     It is noted that the second substrate is formed by above processes. It is further noted that the one pattern process in above embodiments includes: photoresist coating, exposing, developing, etching, and photoresist removing. 
     In step A4, a liquid crystal layer is formed by introducing a liquid crystal molecule into the sealant. 
     In some embodiments, the liquid crystal molecule includes bistable liquid crystal molecules. 
     In step A5, the second substrate covers the liquid crystal layer, such that the common electrode in the second substrate faces towards the first substrate, and the pixel electrode in the first substrate faces towards the second substrate. 
     It is noted that the liquid crystal panel in  FIG.  8    is formed by steps A1 to A5. 
     A handwriting board device is further provided in the embodiments of the present disclosure. Referring to  FIG.  9   ,  FIG.  9    is a schematic structural diagram of a handwriting board device according to some embodiments of the present disclosure. The handwriting board device includes above liquid crystal handwriting board  000  and a position determination assembly  010 . The position determination assembly  010  is electrically connected to a drive assembly in the liquid crystal handwriting board  000 . 
     The position determination assembly  010  is configured to acquire position information of a region to be erased in a liquid crystal panel in the liquid crystal handwriting board  000 , and send the position information of the region to be erased to the drive assembly. 
     As such, upon receiving position information of a region to be erased, the drive assembly applies, based on the position information of the region to be erased, a pixel voltage to a pixel electrode in the region to be erased, such that a voltage difference is developed between the pixel electrode in the region to be erased and the common electrode. Furthermore, the liquid crystal molecules in the region to be erased in the liquid crystal layer rearrange under the action of the voltage difference to erase the handwriting displayed on the region to be erased in the liquid crystal panel. 
     In the present disclosure, the position determination assembly  010  includes an infrared sensor. In the case that the liquid crystal handwriting board  000  is in an erasing mode, the infrared sensor emits an infrared signal to a display region of the liquid crystal handwriting board  000 , so as to detect whether the display region of the liquid crystal handwriting board  000  includes an erasing tool, and determine position information of the erasing tool in the display region of the liquid crystal handwriting board  000 . A position of the erasing tool in the display region of the liquid crystal handwriting board  000  is acted as a region to be erased in the liquid crystal handwriting board  000 . In some embodiments, the erasing tool is an eraser. 
     In the embodiments of the present disclosure, the handwriting board device further includes a toggling switch  020 . The toggling switch  020  is electrically connected to the position determination assembly  010 . The toggling switch  020  is configured to control switching of the liquid crystal handwriting board  000  between the erasing mode and the writing mode. The position determination assembly  010  is further configured to stop acquiring the position information of the region to be erased in the liquid crystal panel in the case that the liquid crystal handwriting board  000  is in the writing mode. 
     In some embodiments, the handwriting board device further includes a controller electrically connected to the toggling switch  020  and the position determination assembly  010 . The controller controls the position determination assembly  010  to be in an operation state or a non-operation state when receiving a control instruction from the toggling switch  020 . In some embodiments, the controller controls the position determination assembly  010  to be in the operation state in the case that the controller receives a control instruction sent from the toggling switch  020  and configured to control the liquid crystal handwriting board  000  to be in the erasing mode. The controller controls the position determination assembly  010  to be in the non-operation state in the case that the controller receives a control instruction sent from the toggling switch  020  and configured to control the liquid crystal handwriting board  000  to be in the writing mode. 
     In the present disclosure, switching of the liquid crystal handwriting board  000  between the erasing mode and the writing mode is performed in many implementations, and the embodiments of the present disclosure illustrate by taking two possible implementations hereinafter as an example. 
     In a first possible implementation, the user taps the toggling switch  020 , and the controller controls the position determination assembly  010  to be in the operation state, such that the liquid crystal handwriting board  000  is in the erasing mode. In this case, it is assumed that the user determines the position information of the erasing tool in the display region of the liquid crystal handwriting board  000  by the position determination assembly  010  in the case that the user performs the erasing operation on the liquid crystal handwriting board  000  through the erasing tool. The position of the erasing tool in the display region of the liquid crystal handwriting board  000  is acted as the region to be erased in the liquid crystal handwriting board  000 . As such, the position information of the region to be erased is acquired by the position determination assembly  010 . Then, the position determination assembly  010  sends the position information of the region to be erased to the drive assembly. As such, the drive assembly applies, based on the position information of the region to be erased, the pixel voltage to the pixel electrode in the region to be erased, such that a voltage difference is developed between the pixel electrode in the region to be erased and the common electrode. Furthermore, the liquid crystal molecules in the region to be erased in the liquid crystal layer rearrange under the action of the voltage difference to erase the handwriting displayed on the region to be erased in the liquid crystal panel. 
     In the case that the user taps the toggling switch  020  again, the controller controls the position determination assembly  010  to be in the non-operation state, such that the liquid crystal handwriting board  000  changes to the writing mode. In this case, the position determination assembly  010  stops acquiring the position information of the region to be erased in the liquid crystal panel, and the user writes on the liquid crystal handwriting board  000  through a writing tool (such as, a writing pen). A part of liquid crystal molecules in the liquid crystal layer  03  convert and reflect visible light under an action of an external pressure, and the liquid crystal handwriting board  000  displays the handwriting. 
     In a second possible implementation, the user taps the toggling switch  020 , and the controller controls the position determination assembly  010  to be in the operation state, such that the liquid crystal handwriting board  000  is in the erasing mode. In this case, it is assumed that the user determines the position information of the erasing tool in the display region of the liquid crystal handwriting board  000  by the position determination assembly  010  in the case that the user performs the erasing operation on the liquid crystal handwriting board  000  through the erasing tool. The position of the erasing tool in the display region of the liquid crystal handwriting board  000  is acted as the region to be erased in the liquid crystal handwriting board  000 . As such, the position information of the region to be erased is acquired by the position determination assembly  010 . Then, the position determination assembly  010  sends the position information of the region to be erased to the drive assembly. As such, the drive assembly applies, based on the position information of the region to be erased, the pixel voltage to the pixel electrode in the region to be erased, such that a voltage difference is developed between the pixel electrode in the region to be erased and the common electrode. Furthermore, the liquid crystal molecules in the region to be erased in the liquid crystal layer rearrange under the action of the voltage difference to erase the handwriting board displayed on the region to be erased in the liquid crystal panel. 
     In the case that the position determination assembly  010  does not acquire the position information of the region to be erased within a predetermined duration, the controller controls the position determination assembly  010  to be in the non-operation state, such that the liquid crystal handwriting board  000  converts to the writing mode. In this case, the position determination assembly  010  stops acquiring the position information of the region to be erased in the liquid crystal panel, and the user writes on the liquid crystal handwriting board  000  through a writing pen. A part of liquid crystal molecules in the liquid crystal layer convert and reflect visible light under an action of an external pressure, and the liquid crystal handwriting board  000  displays the handwriting. 
     In some embodiments, the predetermined duration is one to five seconds. 
     In some embodiments, the erasing mode of the liquid crystal handwriting board  000  further includes an entire plane erasing mode. In some embodiments, the controller in the handwriting board device is further electrically connected to the drive assembly in the liquid crystal handwriting board  000 . In the case that the controller receives a control instruction sent from the toggling switch  020  and configured to control the liquid crystal handwriting board  000  to be in the entire plane erasing mode, the controller sends a corresponding entire plane erasing instruction to the drive assembly, such that the drive assembly applies a pixel voltage to all pixel electrodes in the liquid crystal panel. Thus, voltage differences are developed between all pixel electrodes in the liquid crystal panel and the common electrode, and all liquid crystal molecules in the liquid crystal layer rearrange under the action of the voltage difference to erase the handwriting displayed on all regions in the liquid crystal panel. 
     It is noted that the control instruction configured to control the liquid crystal handwriting board  000  to be in the entire plane erasing mode is an instruction triggered when the user performs a long-press operation on the toggling switch  020 . 
     It is further noted that in the case that the liquid crystal handwriting board  000  is in the entire plane erasing mode, it is necessary to control the position determination assembly  010  to stop acquiring the position information of the region to be erased in the liquid crystal panel. 
     In summary, the handwriting board device in the embodiments of the present disclosure controls switching of the liquid crystal handwriting board between the erasing mode and the writing mode by the toggling switch. The drive assembly electrically connected to the liquid crystal panel applies, based on the position information of the region to be erased acquired by the position determination assembly, the pixel voltage to the bulk pixel electrode in the region to be erased in the case that the liquid crystal handwriting board is in the erasing mode, such that a voltage difference is developed between the pixel electrode in the region to be erased and the common electrode. Thus, the liquid crystal molecules in the region to be erased in the liquid crystal layer rearrange under the action of the voltage difference. As such, a local region of the liquid crystal handwriting board is erased, and the flexibility of the liquid crystal handwriting board in use is improved. 
     A method for controlling a handwriting board device is further provided in the embodiments of the present disclosure. As shown in  FIG.  10   ,  FIG.  10    is a flowchart of a method for controlling a handwriting board device according to some embodiments of the present disclosure. The method for controlling the handwriting board device is applicable to the handwriting board device in above embodiments. In some embodiments, the handwriting board device is the handwriting board device in  FIG.  9   . The method for controlling the handwriting board device includes the following steps. 
     In S 1001 , in the case that liquid crystal handwriting board is in an erasing mode, position information of a region to be erased in a liquid crystal panel in the liquid crystal handwriting board is acquired by a position determination assembly, and the position information of the region to be erased is sent to a drive assembly. 
     In the embodiments of the present disclosure, the liquid crystal handwriting board is controlled to be in the erasing mode by a toggling switch. 
     In S 1002 , a pixel voltage is applied, based on the position information of the region to be erased, to a pixel electrode in the region to be erased by the drive assembly, such that a voltage difference is developed between the pixel electrode in the region to be erased and a common electrode. 
     In summary, in the method for controlling the handwriting board device in the embodiments of the present disclosure, the drive assembly electrically connected to the liquid crystal panel applies, based on position information of a region to be erased, a pixel voltage to a pixel electrode in the region to be erased in the case that the liquid crystal handwriting board is in an erasing mode, such that a voltage difference is developed between the pixel electrode in the region to be erased and the common electrode. Thus, the liquid crystal molecules in the region to be erased in the liquid crystal layer rearrange under the action of the voltage difference. As such, a local region of the liquid crystal handwriting board is erased, and the flexibility of the liquid crystal handwriting board in use is improved. 
     In some embodiments, the method for controlling the handwriting board device further includes the following steps. 
     In step B1, the position determination assembly is controlled to stop acquiring the position information of the region to be erased in the liquid crystal panel in the case that the liquid crystal handwriting board is in a writing mode. 
     In the embodiments of the present disclosure, switching of the liquid crystal handwriting board between the erasing mode and the writing mode is controlled by the toggling switch. 
     In step B2, a pixel voltage is applied to all pixel electrodes by the drive assembly in the case that the liquid crystal handwriting board is in an entire plane erasing mode, such that voltage differences are developed between all pixel electrodes in the region to be erased and the common electrode. 
     It is further noted that in the case that the liquid crystal handwriting board is in the entire plane erasing mode, it is necessary to control the position determination assembly to stop acquiring the position information of the region to be erased in the liquid crystal panel. 
     It is obvious for those skilled in the art that to understand that, above specific operation principles of the method for controlling the handwriting board device are referred to corresponding process in the structure of the handwriting board device in above embodiments for convenient and simply description, which is not repeated herein. 
     It is noted that in the accompanying drawings, the sizes of the layers and regions are exaggerated for clear illustration. In addition, it is understood that when an element or a layer is disposed “on” another element or layer, the element is directly disposed on the another element or there is an intervening layer. In addition, it is understood that when an element or a layer is disposed “under” another element or layer, the element is directly disposed under the another element or there are more than one intervening layer or element. In addition, it is further understood that when a layer or an element is disposed “between” two layers or elements, the layer or element is the only one layer between the two layers or elements or there are more than one intervening layer or element. Similar reference numerals indicate similar elements throughout the present disclosure. 
     In the context, the term “the same layer” refers to a relationship of layers simultaneously formed in one step. In some embodiments, in the case that the gate line and the secondary electrode line are formed by performing one or more steps of the same pattern process, they are in the same layer. In other embodiments, the gate line and the secondary electrode line are formed in the same layer by simultaneously performing the steps of forming the gate line and the secondary electrode line. The term “the same layer” does not always indicate that the thicknesses of the layer or the layers in a cross-section view are the same. 
     In the present disclosure, the terms “first” and “second” are used to descriptive purposes, and are not construed to indicate or imply relative importance. Unless expressly limited otherwise, the term “a plurality of” refers to two or more. 
     Described above are example embodiments of the present disclosure, and are not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements and the like made within the spirit and principles of the present disclosure are included within the scope of protection of the present disclosure.