CN112180628A

CN112180628A - Liquid crystal writing device, local erasing method and display method

Info

Publication number: CN112180628A
Application number: CN202010955957.7A
Authority: CN
Inventors: 李清波; 史新立; 杨猛训
Original assignee: Shandong Lanbeisite Educational Equipment Group Co ltd
Current assignee: Shandong Lanbeisite Educational Equipment Group Co ltd
Priority date: 2020-09-11
Filing date: 2020-09-11
Publication date: 2021-01-05
Also published as: CN112748600A; CN112731706A; CN214151308U; CN112731707A; CN112711151A; CN114706241A; CN112731707B; CN112711151B; CN112731706B; CN112748600B

Abstract

The invention discloses a liquid crystal writing device, a local erasing method and a display method, which comprise the following steps: the conductive layer, the bistable liquid crystal layer and the substrate layer are arranged in sequence; a plurality of pixel units which are arranged in an array shape are integrated on the substrate layer, and a pixel electrode and a switch element connected with the pixel electrode are arranged in each pixel unit; the switching element is turned on to supply a voltage to the pixel electrode. The invention fully utilizes the structural principle of the TFT type liquid crystal display, integrates the array switch unit on the TFT glass layer at the bottom layer by adopting a semiconductor process, can reduce the pixel point to be within 1mm x 1mm, can ensure that the line breaking condition caused by continuous writing can not occur under the condition of the process of extremely small pixel points, reduces the process flow and the control complexity, and improves the control precision.

Description

Liquid crystal writing device, local erasing method and display method

Technical Field

The invention relates to the technical field of liquid crystal writing board structures, in particular to a liquid crystal writing device, a local erasing method and a display method.

Background

The liquid crystal writing film on the market at present has the working principle that the bistable characteristic of liquid crystal is utilized to display and/or erase the writing content on the liquid crystal writing board. For example, cholesteric liquid crystal is used as a writing film, the writing pressure track of a writing pen is recorded by changing the liquid crystal state at a pen point through the pressure acting on a liquid crystal writing board, and then corresponding writing contents are displayed; the cholesteric liquid crystal structure is changed by applying an electric field, so that the writing pressure track on the liquid crystal writing board disappears to realize erasing.

The liquid crystal writing film structure capable of realizing local erasing disclosed by the prior art is basically a soft film structure, namely a first layer of PET conducting layer, a liquid crystal layer and a second layer of PET conducting layer are sequentially arranged, the mode of realizing local erasing is basically that the two layers of PET conducting layers are respectively divided by an etching technology to form different conducting areas, and an erasing electric field is formed in an area to be erased by applying different voltages to each conducting area so as to achieve the aim of local erasing.

However, in this way, it is difficult to segment the extremely small pixels, and if the pixels are too small (e.g., less than 5mm × 5mm), the probability of generating line break is greatly increased; the smaller the pixel is, along with the increase of writing number of times, the more the risk that the broken string appears is, is unfavorable for producing the long-term stability of product performance.

Secondly, due to the limitation of the voltage loading method, when the erasing electric field is formed in the region to be erased, the electric field in the adjacent region cannot be completely zero, so that the other conductive regions may be affected by the erasing voltage and become shallow or disappear while the partial erasing is realized.

In addition, the existing bistable liquid crystal writing device does not have a circuit active display function, all contents need to be presented on the liquid crystal writing device in a writing mode, and for teachers, the existing bistable liquid crystal writing device has some complex formulas or views, so that the existing bistable liquid crystal writing device is very inconvenient to write, and is not beneficial to improving the teaching efficiency and quality.

Disclosure of Invention

In order to solve the problems, the invention provides a liquid crystal writing device, a local erasing method and a display method, each pixel point is independently controlled by using a TFT (thin film transistor) process, and the occurrence of line breakage caused by continuous writing can be avoided on the premise of realizing the segmentation of extremely small pixel points.

In order to achieve the above purpose, in some embodiments, the following technical solutions are adopted:

a liquid crystal writing apparatus comprising: the conductive layer, the bistable liquid crystal layer and the substrate layer are arranged in sequence; a plurality of pixel units which are arranged in an array shape are integrated on the substrate layer, and a pixel electrode and a switch element connected with the pixel electrode are arranged in each pixel unit; the switching element is turned on to supply a voltage to the pixel electrode.

Furthermore, a plurality of first conducting wires and a plurality of second conducting wires are respectively integrated on the substrate layer corresponding to each longitudinal column and each transverse column of the pixel units according to the arrangement mode of the pixel units; the first wire is used for providing a control voltage for enabling the switching element to be switched on or switched off; the second conductor is used for providing an input voltage for the switching element.

Still further, the switching element includes: the grid electrode of the TFT is connected with a first wire, and the source electrode of the TFT is connected with a second wire; the drain electrode of the TFT is connected with the corresponding pixel electrode;

and the drain electrode of the TFT can also be connected with an energy storage capacitor, and the leading-out electrode wire of each energy storage capacitor is connected with the leading-out electrode wire of the conducting layer.

In other embodiments, the following technical solutions are adopted:

a partial erasing method of a liquid crystal writing apparatus, comprising: controlling the on and input voltages of the switching element to apply a first voltage to the pixel unit covering the local erase region; applying a second voltage to the conductive layer; the first voltage and the second voltage form an erasing electric field at the position where the pixel unit and the conducting layer are overlapped in space, and local erasing is achieved.

The specific voltage application process comprises:

all the switch elements are conducted through the first conducting wires, and second voltages are respectively applied to all the pixel units and the conducting layers of the substrate layer through the second conducting wires;

keeping applying a second voltage to the conductive layer, and enabling the switching element of the pixel unit to be conducted through a first conducting wire connected with the pixel unit covering the local erasing area; applying a first voltage to the pixel unit through a second wire connected with the pixel unit covering the local erasing area;

for the rest pixel units connected with the first lead, the switch elements are also conducted, and second voltage is applied to the pixel units through second leads connected with the pixel units;

and the switch elements of the rest pixel units are controlled to be in a closed state, so that the local erasing area can be erased.

Further, in the first half period of the applied voltage, the second voltage is the erase voltage Vcom, and the first voltage V satisfies: v is more than or equal to 2.5Vcom and more than or equal to 1.5 Vcom;

in the second half period of the applied voltage, the second voltage is the erase voltage Vcom, and the first voltage V satisfies: v is more than or equal to 0.5Vcom and more than or equal to-0.5 Vcom.

The first half period and the second half period can be interchanged, and the erasing can be realized in any half period.

In other embodiments, the following technical solutions are adopted:

a display method of a liquid crystal writing device comprises the following steps:

receiving a display instruction of a control terminal for setting content, and acquiring a display position of the content;

applying a first voltage to a pixel unit covering the display position based on the on and input voltages of the display position control switch element; applying a second voltage to the conductive layer; the electric field formed by the first voltage and the second voltage at the position where the pixel unit and the conducting layer are overlapped in space can realize the display of the set content.

The specific voltage application process comprises:

enabling all the switch elements to be conducted through the first conducting wires, applying second voltage to all the pixel units of the substrate layer through the second conducting wires, and applying second voltage to the conducting layer;

keeping applying a second voltage to the conductive layer, and enabling the switch element of the pixel unit to be conducted through a first conducting wire connected with the pixel unit covering the display position; applying a first voltage to a pixel unit covering a display position through a second wire connected with the pixel unit;

and the switch elements of the rest pixel units are controlled to be in a closed state, so that the set content can be erased.

Further, the magnitude of the electric field formed by the first voltage and the second voltage at the position where the pixel unit is overlapped with the conducting layer in space is determined according to the liquid crystal characteristic in the bistable liquid crystal layer.

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention fully utilizes the structural principle of the TFT type liquid crystal display, integrates the array switch unit on the TFT glass layer at the bottom layer by adopting a semiconductor process, can reduce the pixel point to be within 1mm x 1mm, can ensure that the line breaking condition caused by continuous writing can not occur under the condition of the process of extremely small pixel points, reduces the process flow and the control complexity, and improves the control precision.

(2) The invention does not need to divide the top conductive layer, controls each pixel unit on the TFT glass layer independently, only needs to apply voltage to the pixel unit covering the local erasing area, and does not apply auxiliary voltage to other areas (similar to executing a one-key erasing function for each pixel unit independently), thereby avoiding the area outside the local erasing area from being shallowed or disappeared due to the influence of the erasing electric field.

(3) The liquid crystal writing device can also have a display function, namely, the liquid crystal writing device can display the appointed content on the computer terminal, so that a teacher can directly display some contents such as formulas or diagrams on the liquid crystal blackboard during teaching without writing by himself, a large amount of writing time is saved, and meanwhile, some complex contents can be displayed on the liquid crystal blackboard, and a better teaching purpose is achieved.

(4) The writing and local erasing positioning circuit is integrated on the TFT glass layer, so that the writing piece or the erasing piece can be positioned, on the basis, the gesture screen projection function can be added, and the cooperative interaction of the liquid crystal writing device and other terminals is realized.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the application and, together with the description, serve to explain the application and are not intended to limit the application.

FIG. 1 is a schematic structural diagram of a liquid crystal writing device disclosed in an embodiment of the present invention;

fig. 2 is a circuit configuration diagram of a switching element disclosed in the embodiment of the present invention;

FIG. 3 is a schematic diagram of a circuit structure integrated on a substrate layer according to an embodiment of the disclosure;

FIG. 4 is a turn-on characteristic curve of a TFT disclosed in an embodiment of the present invention;

FIGS. 5(a) - (b) are schematic diagrams of voltage application of each pixel unit on the TFT glass layer and voltage difference between the conductive layer and the TFT glass layer at the beginning in the second embodiment;

FIGS. 6(a) - (b) are the voltage application diagrams of each pixel unit on the TFT glass layer and the voltage difference between the conductive layer and the TFT glass layer in the first half period of the voltage application in the second embodiment;

FIGS. 7(a) - (b) are the second half cycle of voltage application, voltage application schematic diagram of each pixel unit on the TFT glass layer and the voltage difference between the conductive layer and the TFT glass layer in the second embodiment;

FIGS. 8(a) - (b) are diagrams illustrating voltage application of each pixel unit on the TFT glass layer and the voltage difference between the conductive layer and the TFT glass layer at the beginning in the third embodiment;

FIGS. 9(a) - (b) are the voltage application diagrams of each pixel unit on the TFT glass layer and the voltage difference between the conductive layer and the TFT glass layer in the first half period of the voltage application in the third embodiment;

fig. 10(a) - (b) are the second half cycle of voltage application, the schematic diagram of voltage application of each pixel unit on the TFT glass layer and the voltage difference between the conductive layer and the TFT glass layer in the third embodiment.

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

Example one

According to an embodiment of the present invention, an embodiment of a liquid crystal writing apparatus is disclosed, referring to fig. 1, including: the conductive layer, the bistable liquid crystal layer and the substrate layer are arranged from top to bottom in sequence. The conducting layer is not divided, a plurality of pixel units are integrated on the substrate layer, the pixel units are arranged in an array mode, and a pixel electrode and a switch element connected with the pixel electrode are arranged in each pixel unit; the switching element being on can provide a voltage to the pixel electrode connected thereto.

On the substrate layer, a plurality of first conducting wires and a plurality of second conducting wires are respectively integrated corresponding to each column and each row of the pixel units; the arrangement directions of the first conducting wire and the second conducting wire are mutually vertical; the switching element in each pixel unit is respectively connected with a first lead and a second lead adjacent to the switching element, and the first lead is used for providing voltage for enabling the switching element to be switched on or switched off; the second conductor is used for providing the input voltage of the switching element.

As an alternative embodiment, the switching element is further connected with an energy storage element, and an outgoing line of the energy storage element is connected with an electrode outgoing line of the conductive layer; the switching element is switched on to charge the energy storage element.

Specifically, the switching element includes: the TFT is characterized in that the TFT comprises a thin film transistor (hereinafter referred to as TFT), the grid electrode of the TFT is connected with a first lead, the source electrode of the TFT is connected with a second lead, and the drain electrode of the TFT is connected with a corresponding pixel electrode.

The drain of the TFT is also connected to one end of a storage capacitor C1, and the other end lead of the storage capacitor C1 is connected to the electrode lead of the conductive layer.

In this embodiment, the energy storage capacitor C1 is used to store energy, and certainly, the energy storage capacitor C1 may be used by a capacitor formed between the conductive layer and the substrate layer, so that the energy storage capacitor C1 may be omitted; in the following embodiments, the following embodiments are described by taking the storage capacitor C1 as an example, and it should be understood by those skilled in the art that this is not a limitation to the scope of the present disclosure, and in other embodiments, the storage capacitor C1 may not be provided, and the capacitor formed between the conductive layer and the substrate layer may be used for the purpose of energy storage.

Fig. 2 shows a circuit structure of the switching element module, wherein the first plate represents a pixel electrode region corresponding to each or some adjacent pixel units on the substrate layer; the second plate represents the conductive layer.

In this embodiment, the base layer is a TFT glass layer on which different circuit structures can be integrated by a semiconductor process. Fig. 3 is a schematic diagram showing a circuit structure integrated on the substrate layer in the present embodiment, and a circuit diagram of a switching element module thereon is an equivalent circuit diagram according to fig. 2.

In some embodiments, electrode lines are respectively led out from the TFT glass layer and the conductive layer; is used for connecting a voltage driving circuit which can provide required voltage.

As an optional implementation mode, the conductive particles are added into the frame glue, and the electrodes of the whole conductive layer are connected to the FPC golden fingers of the TFT glass layer, so that the electrode extraction of the whole module is extracted from the TFT glass layer, which is simpler and more stable than the original mode of extracting the electrodes from the conductive layer and the TFT glass layer respectively.

Example two

According to the embodiment of the invention, an embodiment of a local erasing method of a liquid crystal writing device is disclosed, and the method is based on the structure of the liquid crystal writing device disclosed in the first embodiment and is realized by the following steps: controlling the on and input voltages of the switching element to apply a first voltage to the pixel unit covering the local erase region; applying a second voltage to the conductive layer; the first voltage and the second voltage form an erasing electric field at the position where the pixel unit and the conducting layer are overlapped in space, and local erasing is achieved.

Specifically, the gate G of the TFT is supplied with a turn-on voltage through the first wire, and the source S of the TFT is supplied with a voltage required for partial erasing through the second wire, so as to implement a partial erasing function of the liquid crystal writing device.

The on-characteristic curve of the TFT is shown in fig. 4, where the abscissa in fig. 4 is voltage and the ordinate is current; applying a voltage V to the gate G_GoffWhen the TFT cut-off current is minimum, a voltage V is applied to the gate G_onWhen this occurs, the TFT approaches the maximum on current.

Referring to fig. 3, a voltage control method of implementing partial erase is as follows:

(1) and respectively applying a first voltage to each pixel unit of the TFT glass layer and the conductive layer, wherein the voltage difference between the conductive layer and each pixel unit of the TFT glass layer is zero.

Specifically, the TFT grid G of each pixel unit of the TFT glass layer is provided with a turn-on voltage V through a first lead_onA first voltage is provided for a TFT source electrode S of each pixel unit of the TFT glass layer through a second lead; thus, the TFT of each pixel unitAre turned on so that the voltage applied to each pixel electrode is the first voltage and the voltage across each storage capacitor C1 is precharged to the first voltage. And the voltage applied on the conductive layer is also the first voltage, so that the electric field of each pixel unit of the whole TFT glass layer and the corresponding area of the conductive layer are all zero, and local erasing can not occur at the moment.

(2) In the first half period of voltage application, applying a second voltage to pixel units covering a local erasing area in the TFT glass layer, keeping the rest pixel units at the first voltage, and keeping the voltage applied to the conductive layer at the first voltage; at this time, the voltage difference between the pixel unit and the conductive layer, which only covers the local erasing area, is the second voltage-the first voltage, the difference reaches the erasing electric field, and the voltage difference of the rest areas is still zero, so that the local erasing area can be erased.

Specifically, a first wire connected to a pixel cell covering a local erase region is supplied with a turn-on voltage V_onThereby providing turn-on voltage for the TFT gates G of all the pixel units connected with the first lead; the TFTs of all the pixel units connected with the first lead are conducted; providing voltage V for other pixel units through the remaining first conductor_GoffSo that the other pixel units are not conductive.

The second voltage is supplied to the second wire connected to the source electrode S of the TFT covering the pixel unit of the partial erase region, and the first voltage is supplied to the second wire connected to the source electrodes S of the TFTs of the remaining turned-on pixel units.

At this time, for the pixel unit covering the local erasing area, the on voltage of the TFT is the second voltage, the electric field formed between the area and the corresponding area of the conductive layer is the second voltage — the first voltage, and the difference reaches the erasing electric field; for the rest of the turned-on pixel units, the turn-on voltage of the TFT is a first voltage, and the electric fields formed between the regions and the corresponding regions of the conducting layer are all zero; for the non-conductive pixel units, because the TFT is not conductive, the voltage of the previously pre-charged energy storage capacitor C1 cannot be discharged, so that the voltages corresponding to the pixel units are equal to the voltage of the energy storage capacitor, which are all the first voltages, and the electric fields formed between the areas and the corresponding areas of the conductive layer are all zero.

Therefore, only the writing of the partially erased area is erased, and the writing of the rest area is not affected.

As an alternative embodiment, the second voltage is selected as the erase voltage Vcom, and the first voltage V satisfies: v is more than or equal to 2.5Vcom and more than or equal to 1.5 Vcom;

(3) in the second half period of voltage application, a third voltage is applied to the pixel units covering the local erasing area in the TFT glass layer, the rest pixel units still keep the first voltage, and the voltage applied to the conductive layer also keeps the first voltage; at this time, the voltage difference between the pixel unit and the conductive layer which covers only the local erasing area is the third voltage-the first voltage- (the second voltage-the first voltage), the difference reaches the erasing electric field, and the voltage difference of the rest area is still zero, so that the local erasing area can be erased.

The specific voltage control implementation is the same as the previous half cycle, and is not described again.

As an alternative embodiment, the second voltage is the erase voltage Vcom, and the third voltage V satisfies: v is more than or equal to 0.5Vcom and more than or equal to-0.5 Vcom.

Of course, the first half period and the second half period can be interchanged, and any half period can be used for erasing.

As a more specific embodiment, taking erasing the writing in the pixel unit K corresponding to VG1 and VS1 in fig. 3 as an example, the first voltage is selected as the erase voltage Vcom, the second voltage is selected as 2Vcom, and the third voltage is selected as zero; in the following figures, only the voltage application of 4 pixel units adjacent to the pixel unit and the voltage difference with the conductive layer are shown.

Initially, applying a voltage Vcom to each pixel unit of the TFT glass layer and the conductive layer respectively, wherein at this time, a voltage difference between the conductive layer and each pixel unit of the TFT glass layer is zero; a schematic diagram of voltage application of each pixel unit on the TFT glass layer and a voltage difference between the conductive layer and the TFT glass layer are shown in fig. 5(a) - (b).

In the first half period of voltage application, in the TFT glass layer, applying a conducting voltage to the connected TFT through a first conducting wire VG1, applying a voltage 2Vcom to the pixel unit K through a second conducting wire VS1, and applying a voltage Vcom to the rest pixel units connected with the first conducting wire VG1 through second conducting wires VS2-VS 6; an off-voltage is applied to the TFTs connected to it via first conductors VG2-VG4 so that none of these TFTs is conducting.

Thus, the voltage applied to the pixel unit K is 2Vcom, the remaining pixel units still maintain the voltage Vcom, and the voltage applied to the conductive layer also maintains the voltage Vcom; at this time, only the voltage difference between the pixel unit K and the conductive layer is the erasing voltage Vcom, and the voltage difference of the rest areas is still zero, so that the local erasing area can be erased; a schematic diagram of voltage application of each pixel unit on the TFT glass layer and a voltage difference between the conductive layer and the TFT glass layer are shown in fig. 6(a) - (b).

In the latter half period of voltage application, in the TFT glass layer, a first conducting wire VG1 is used for applying a conducting voltage to the connected TFT, a second conducting wire VS1 is used for applying a voltage 0 to the pixel unit K, and second conducting wires VS2-VS6 are used for applying a voltage Vcom to the rest pixel units connected with the first conducting wire VG 1; an off-voltage is applied to the TFTs connected to it via first conductors VG2-VG4 so that none of these TFTs is conducting.

Thus, the voltage applied to the pixel unit K is 0, the voltage Vcom is still maintained in the remaining pixel units, and the voltage applied to the conductive layer is also maintained as the voltage Vcom; at this time, only the voltage difference between the pixel unit K and the conductive layer is the erasing voltage-Vcom, and the voltage difference of the rest areas is still zero, so that the local erasing area can be erased; a schematic diagram of voltage application of each pixel unit on the TFT glass layer and a voltage difference between the conductive layer and the TFT glass layer are shown in fig. 7(a) - (b).

As can be seen from fig. 5(a) -7 (b), the voltage difference (electric field) formed between the pixel unit and the conductive layer covering only the local erasing area reaches the erasing electric field, and the electric fields at the rest positions are all zero and are not affected.

In this embodiment, the erasing voltage is a voltage required to completely erase the handwriting, and the erasing electric field is an electric field formed between corresponding areas of the two conductive layers by the erasing voltage.

The liquid crystal of this embodiment adoption TFT glass layer writes the device, compares in the membrane material structure of generally using on the existing market, realizes that the control process of local erasure is simpler and accurate, and control flexibility ratio increases, and it is better to erase the effect, can not exert an influence to other regions.

Simultaneously, the liquid crystal of adopting TFT glass layer of this embodiment writes the device, not only can realize writing and locally erase the function, still remains the liquid crystal and writes advantages such as energy-conservation, environmental protection, eyeshield, no blue light, no dust, no consumptive material, furthest's reduction teaching blackboard writing drawing doodle of device.

EXAMPLE III

According to the embodiment of the invention, an embodiment of a display method of a liquid crystal writing device is disclosed, and the method is based on the structure of the liquid crystal writing device disclosed in the first embodiment and is realized by the following steps:

Specifically, the gate G of the TFT is provided with a turn-on voltage through the first wire, and the source S of the TFT is provided with a voltage required for display through the second wire, so as to implement a display function of the liquid crystal writing device.

Referring to fig. 3, a voltage control method for realizing the display function is as follows:

Specifically, the TFT grid G of each pixel unit of the TFT glass layer is provided with a turn-on voltage V through a first lead_onA first voltage is provided for a TFT source electrode S of each pixel unit of the TFT glass layer through a second lead; in this way, the TFT of each pixel cell is turned on, so that the voltage applied to each pixel electrode is the first voltage, and the voltage across each storage capacitor C1 is also precharged to the first voltage. And the voltage applied on the conducting layer is also the first voltage, so that the electric field of each pixel unit of the whole TFT glass layer and the corresponding area of the conducting layer are all zero, and the electric field does not have any influence on the handwriting at the moment.

(2) In the first half period of voltage application, applying a second voltage to the pixel units covering the display positions in the TFT glass layer, keeping the rest pixel units at the first voltage, and keeping the voltage applied to the conductive layer at the first voltage; at this time, the voltage difference between the pixel unit covering the display position and the conductive layer is the second voltage-the first voltage, the difference reaches the electric field required by the liquid crystal display, and the voltage difference of the rest area is still zero, so that the display of the set content can be realized.

In particular, a first conductor connected to a pixel cell covering a display position is supplied with a turn-on voltage V_onThereby providing turn-on voltage for the TFT gates G of all the pixel units connected with the first lead; the TFTs of all the pixel units connected with the first lead are conducted; providing voltage V for other pixel units through the remaining first conductor_GoffSo that the other pixel units are not conductive.

The second voltage is supplied to the second wire connected to the source S of the TFT covering the pixel cell at the display position, and the first voltage is supplied to the second wire connected to the source S of the TFT of the remaining conducting pixel cell.

At this time, for the pixel unit covering the display position, the on voltage of the TFT is the second voltage, the electric field formed between the region and the corresponding region of the conductive layer is the second voltage-the first voltage, and the difference reaches the electric field required for liquid crystal display; for the rest of the turned-on pixel units, the turn-on voltage of the TFT is a first voltage, and the electric fields formed between the regions and the corresponding regions of the conducting layer are all zero; for the non-conductive pixel units, because the TFT is not conductive, the voltage of the previously pre-charged energy storage capacitor C1 cannot be discharged, so that the voltages corresponding to the pixel units are equal to the voltage of the energy storage capacitor, which are all the first voltages, and the electric fields formed between the areas and the corresponding areas of the conductive layer are all zero.

Therefore, the setting contents are displayed at the display position, and the remaining area is not affected.

(3) In the second half period of voltage application, a third voltage is applied to the pixel units covering the display positions in the TFT glass layer, the rest pixel units still maintain the first voltage, and the voltage applied to the conductive layer also maintains the first voltage; at this time, the voltage difference between the pixel unit covering only the display position and the conductive layer is the third voltage-the first voltage- (the second voltage-the first voltage), the difference reaches the electric field required by the liquid crystal display, and the voltage difference in the rest areas is still zero.

The first half period and the second half period can be interchanged, and any half period can be selected to realize display.

It can be understood that the values of the second voltage and the first voltage and the difference value thereof are determined by the characteristics of the bistable liquid crystal layer, and can be obtained by those skilled in the art through limited implementation.

As a more specific embodiment, taking the example of displaying the setting content in the pixel cell K corresponding to VG1 and VS1 in fig. 3 as an example, the value of the first voltage is selected as the erase voltage Vcom, the value of the second voltage is selected as 6Vcom, and the value of the third voltage is selected as zero; in the following figures, only the voltage application of 4 pixel units adjacent to the pixel unit and the voltage difference with the conductive layer are shown.

Initially, applying a voltage Vcom to each pixel unit of the TFT glass layer and the conductive layer respectively, wherein at this time, a voltage difference between the conductive layer and each pixel unit of the TFT glass layer is zero; a schematic diagram of voltage application of each pixel unit on the TFT glass layer and a voltage difference between the conductive layer and the TFT glass layer are shown in fig. 8(a) - (b).

In the first half period of voltage application, in the TFT glass layer, applying a conducting voltage to the connected TFT through a first conducting wire VG1, applying a voltage 6Vcom to the pixel unit K through a second conducting wire VS1, and applying a voltage Vcom to the rest pixel units connected with the first conducting wire VG1 through second conducting wires VS2-VS 6; an off-voltage is applied to the TFTs connected to it via first conductors VG2-VG4 so that none of these TFTs is conducting.

Thus, the voltage applied to the pixel unit K is 6Vcom, the remaining pixel units still maintain the voltage Vcom, and the voltage applied to the conductive layer also maintains the voltage Vcom; at this time, only the voltage difference between the pixel unit K and the conductive layer is the erase voltage 5Vcom, and the voltage difference of the rest regions is still zero, so that the display of the set content can be realized; a schematic diagram of voltage application of each pixel unit on the TFT glass layer and a voltage difference between the conductive layer and the TFT glass layer are shown in fig. 9(a) - (b).

In the latter half period of voltage application, in the TFT glass layer, a conducting voltage is applied to the TFT connected with the TFT through a first conducting wire VG1, a voltage-4 Vcom is applied to the pixel unit K through a second conducting wire VS1, and a voltage Vcom is applied to the rest pixel units connected with the first conducting wire VG1 through second conducting wires VS2-VS 6; an off-voltage is applied to the TFTs connected to it via first conductors VG2-VG4 so that none of these TFTs is conducting.

Thus, the voltage applied to the pixel cell K is-4 Vcom, the remaining pixel cells still maintain the voltage Vcom, and the voltage applied to the conductive layer also maintains the voltage Vcom; at this time, only the voltage difference between the pixel unit K and the conductive layer is the erase voltage of-5 Vcom, and the voltage difference of the rest regions is still zero, so that the display of the set content can be realized; a schematic diagram of voltage application of each pixel unit on the TFT glass layer and a voltage difference between the conductive layer and the TFT glass layer are shown in fig. 10(a) - (b).

As can be seen from fig. 8 a to 10 b, the voltage difference (electric field) formed between the pixel unit and the conductive layer at the display position reaches the electric field required for the liquid crystal display, and the electric fields at the rest positions are all zero and are not affected.

The display function of the liquid crystal writing device may be present alone or may be present together with the partial erasing function in the second embodiment, and the function may be switched as needed when the liquid crystal writing device is used.

The liquid crystal writing device of this embodiment can realize the demonstration to setting for the content, makes things convenient for mr to the demonstration of some complicated contents at the teaching in-process, avoids the restriction of blackboard writing.

Example four

On the basis of the liquid crystal writing device disclosed in the first embodiment, the second embodiment or the third embodiment, a positioning circuit is further integrated on the TFT glass layer, and is used for positioning a writing pen or an eraser so as to realize position positioning during partial erasing or position positioning of writing or other positioning functions.

The positioning circuit can be realized by adopting an electromagnetic positioning mode, a capacitance positioning mode, an infrared positioning mode, an ultrasonic positioning mode or an image positioning mode, the positioning modes are all the positioning modes disclosed in the prior art, and the specific realization process is not detailed.

When the capacitive positioning or infrared positioning mode is adopted, the gesture can be recognized in the positioning mode, so that the display terminal communicating with the liquid crystal writing device responds to the set execution action according to the recognized gesture type, and the gesture screen projection function is realized.

Such as: in a school or a classroom environment with a large area and an environment with a wide left-right width of the whole liquid crystal blackboard, since the display content of the large display screen needs to be switched back and forth between the synchronous display of the content of the liquid crystal blackboard and the display of other content, a teacher needs to walk back and forth to maximize and minimize the synchronous display software of the large display screen; the operation process is relatively complicated.

Through the gesture screen projection function of the embodiment, the cooperative interaction between the liquid crystal writing device and other terminals, such as a liquid crystal display large screen, can be realized. Specifically, the maximization and minimization operation of the synchronous display software of the large display screen end can be triggered by recognizing a specific gesture, so that when a teacher writes at the liquid crystal blackboard end, the displayed content can be controlled to be switched by the large display screen end only by making a set gesture, and the operation process is simple and rapid.

In other embodiments, the content displayed on the liquid crystal writing device may also be transmitted to the display terminal for displaying through the set gesture.

Of course, in order to prevent the gesture from being triggered by mistake, the gesture recognition and the moving distance condition may be simultaneously satisfied to perform the action response.

It should be noted that the above circuit structure is integrated on the TFT glass layer by using a semiconductor process, which is a relatively mature technology and can be fully implemented by those skilled in the art, and is not described in detail.

EXAMPLE five

On the basis of the liquid crystal writing device disclosed in the first embodiment, the second embodiment, the third embodiment or the fourth embodiment, specific application products of the liquid crystal writing device are disclosed, such as:

the liquid crystal writing device is applied to a writing board, a drawing board or a blackboard to realize the local erasing function or the display function or other functions disclosed above.

Specifically, the liquid crystal writing device according to the embodiment of the present invention may be applied to a light energy writing board, a light energy liquid crystal writing board, a light energy large liquid crystal writing blackboard, a light energy dust-free writing board, a light energy portable blackboard, an electronic drawing board, an lcd electronic writing board, an electronic notepad, a doodle board, a child writing board, a child doodle drawing board, an eraser function sketch board, a liquid crystal electronic drawing board, a color liquid crystal writing board, or other related products that can be known to those skilled in the art.

Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is not intended to limit the scope of the present invention, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive efforts by those skilled in the art based on the technical solution of the present invention.

Claims

1. A liquid crystal writing apparatus, comprising: the conductive layer, the bistable liquid crystal layer and the substrate layer are arranged in sequence; the array-shaped pixel array structure comprises a substrate layer, a plurality of pixel units are integrated on the substrate layer, a pixel electrode and a switch element connected with the pixel electrode are arranged in each pixel unit, and the switch element is switched on to provide voltage for the pixel electrode.

2. The liquid crystal writing apparatus according to claim 1, wherein a plurality of first conductive lines and a plurality of second conductive lines are respectively integrated on the base layer corresponding to each column and each row of the pixel units according to the arrangement of the pixel units; the first wire is used for providing a control voltage for enabling the switching element to be switched on or switched off; the second conductor is used for providing an input voltage for the switching element.

3. A liquid crystal writing apparatus as claimed in claim 2, wherein said switching element comprises: the grid electrode of the TFT is connected with a first wire, and the source electrode of the TFT is connected with a second wire; and the drain electrode of the TFT is connected with the corresponding pixel electrode.

4. The liquid crystal writing apparatus of claim 1, wherein the switching element is further connected to an energy storage element, and a lead line of the energy storage element is connected to an electrode lead line of the conductive layer.

5. The liquid crystal writing apparatus of claim 1, wherein the electrode lines of the conductive layer are connected to the base layer, and the electrodes are drawn only from the base layer.

6. The liquid crystal writing apparatus of claim 1, wherein the substrate layer has integrated thereon a positioning circuit; the positioning circuit realizes the positioning of the writing piece or the erasing piece by adopting an electromagnetic positioning mode, a capacitance positioning mode, an infrared positioning mode, an ultrasonic positioning mode or an image positioning mode.

7. The liquid crystal writing apparatus as claimed in claim 6, wherein when the positioning circuit adopts a capacitive positioning method or an infrared positioning method, the positioning circuit is further capable of recognizing a set gesture, so that a display terminal communicating with the liquid crystal writing apparatus responds to a set execution action according to the recognized gesture type.

8. A liquid crystal writing apparatus as claimed in any one of claims 1 to 7, wherein the liquid crystal writing apparatus comprises: blackboard, drawing board or writing board.

9. A partial erasing method of a liquid crystal writing apparatus as claimed in any one of claims 1 to 7, comprising: controlling the on and input voltages of the switching element to apply a first voltage to the pixel unit covering the local erase region; applying a second voltage to the conductive layer; the first voltage and the second voltage form an erasing electric field at the position where the pixel unit and the conducting layer are overlapped in space, and local erasing is achieved.

10. The local erasing method as claimed in claim 9, which is implemented based on the liquid crystal writing apparatus as claimed in claim 3, wherein the specific voltage applying process comprises:

11. The partial erasing method of claim 9 or 10,

in the first half period of the applied voltage, the second voltage is an erase voltage Vcom, and the first voltage V satisfies: v is more than or equal to 2.5Vcom and more than or equal to 1.5 Vcom;

alternatively, the first and second electrodes may be,

The first half period and the second half period can be interchanged, and any half period can be adopted to realize erasing.

12. A display method of a liquid crystal writing apparatus according to any one of claims 1 to 7, comprising:

13. The display method according to claim 12, which is implemented based on the liquid crystal writing apparatus according to claim 3, wherein the specific voltage application process includes:

and the switching elements of the rest pixel units are controlled to be in a closed state, so that the display of the set content can be realized.

14. The display method of claim 12, wherein the magnitude of the electric field formed by the first voltage and the second voltage at the location where the pixel cell spatially overlaps the conductive layer is determined by the characteristics of the liquid crystal in the bistable liquid crystal layer.