CN113759623B - Liquid crystal writing board, display method and writing device thereof - Google Patents

Abstract

The application provides a liquid crystal writing board, a display method thereof and a writing device, wherein a bistable liquid crystal layer in the liquid crystal writing board comprises a plurality of pixel units, each pixel unit comprises a first liquid crystal subunit, a second liquid crystal subunit and a third liquid crystal subunit which are arranged side by side along the direction parallel to a first transparent substrate, and any two adjacent liquid crystal subunits are isolated by a transparent spacer; the first liquid crystal subunit, the second liquid crystal subunit and the third liquid crystal subunit are configured to reflect red light, green light and blue light respectively under the action of a first preset electric field, and are configured to be in a scattering state under the action of a second preset electric field. The bistable liquid crystal layer displays white under the action of a first preset electric field, each liquid crystal subunit is converted into a scattering state under the action of a second preset electric field, the color of the shading substrate is displayed, black or color handwriting can be written under a white background, and the handwriting definition of the writing board is greatly improved.

Description

Liquid crystal writing board, display method and writing device thereof

Technical field

The present application relates to the field of display technology, and specifically to a liquid crystal writing board, a display method thereof, and a writing device.

Background technique

Currently, there are three types of educational writing boards on the market: traditional blackboards, white plastic boards, and electronic handwriting blackboards. Traditional blackboards are made of black frosted glass and need to be written with white chalk. The accumulation of chalk dust over time has an impact on human health, such as irritating the upper respiratory tract mucosa. White plastic You need to buy paint pens for the board. It is often encountered that the paint pens run out of ink, and traditional blackboards and whiteboards will encounter problems with wiping them clean over a long period of time.

Therefore, with the development of liquid crystal display technology, liquid crystal writing tablets are increasingly used in fields such as education and business applications. However, the comprehensive display brightness and contrast of common writing tablets currently on the market are low, resulting in low handwriting clarity and poor user experience.

Contents of the invention

In response to the above problems, the present application provides a liquid crystal writing board, a display method thereof, and a writing device, which can solve the technical problem of low handwriting clarity in electronic writing boards in the prior art.

In a first aspect, the present application provides a liquid crystal writing tablet, including: a first transparent substrate and a light-shielding substrate arranged oppositely, and a bistable liquid crystal layer located between the first transparent substrate and the light-shielding substrate;

Wherein, the first transparent substrate is provided with a first transparent electrode plate on a side close to the bistable liquid crystal layer;

The light-shielding substrate is provided with a second transparent electrode plate on a side close to the bistable liquid crystal layer;

The bistable liquid crystal layer includes a plurality of pixel units, each pixel unit including a first liquid crystal sub-unit, a second liquid crystal sub-unit and a third liquid crystal sub-unit arranged side by side in a direction parallel to the first transparent substrate, Any two adjacent liquid crystal sub-units are separated by transparent spacers;

The first liquid crystal sub-unit, the second liquid crystal sub-unit and the third liquid crystal sub-unit are configured to respectively reflect red light, green light and blue light under the action of a first preset electric field, and are configured to It is in a scattering state under the action of the second preset electric field.

In some embodiments, in the above-mentioned liquid crystal writing tablet, the second preset electric field is greater than the first preset electric field;

When the bistable liquid crystal layer is under the first preset electric field and the side of the first transparent substrate away from the bistable liquid crystal layer is pressed, the bistable liquid crystal layer is at the pressed position. The electric field is transformed from the first preset electric field to the second preset electric field.

In some embodiments, the above-mentioned liquid crystal writing pad further includes a touch component.

In some embodiments, in the above-mentioned liquid crystal writing tablet, the first transparent electrode plate includes a plurality of first sub-electrodes arranged in an array;

The second transparent electrode plate includes a plurality of second sub-electrodes arranged in an array.

In some embodiments, in the above-mentioned liquid crystal writing tablet, the color of the light-shielding substrate is configured to be the color of writing handwriting.

In some embodiments, in the above-mentioned liquid crystal writing board, the color of the light-shielding substrate is selected from any color except white.

In some embodiments, in the above-mentioned liquid crystal writing board, the materials of the first liquid crystal subunit, the second liquid crystal subunit and the third liquid crystal subunit all include cholesteric liquid crystal.

In some embodiments, in the above-mentioned liquid crystal writing board, the liquid crystal molecules in the first liquid crystal subunit, the second liquid crystal subunit and the third liquid crystal subunit are in a plane state under the first preset electric field. The texture state is in the focal conic texture state under the second preset electric field.

In some embodiments, in the above-mentioned liquid crystal writing tablet, the light-shielding substrate includes a second transparent substrate, and a light-shielding layer disposed between the second transparent substrate and the second transparent electrode plate.

In some embodiments, in the above-mentioned liquid crystal writing tablet, the light-shielding layer is provided with a plurality of protrusions on a side close to the second transparent electrode plate.

In some embodiments, the above-mentioned liquid crystal writing tablet also includes:

a driving unit electrically connected to the first transparent electrode plate and the second transparent electrode plate, the driving unit being configured to apply a voltage between the first transparent electrode plate and the second transparent electrode plate, To apply a corresponding electric field to the bistable liquid crystal layer.

In a second aspect, this application provides a display method for a liquid crystal writing tablet as described in any one of the first aspects, including:

A first voltage is applied between the first transparent electrode plate and the second transparent electrode plate to apply the first preset electric field to the bistable liquid crystal layer, so that the first liquid crystal subunit, The second liquid crystal subunit and the third liquid crystal subunit respectively reflect red light, green light and blue light under the action of the first preset electric field, so that the bistable liquid crystal layer is in the first preset electric field. Displays white under the action of the preset electric field;

In response to a writing operation acting on the side of the first transparent substrate away from the bistable liquid crystal layer, the electric field of the bistable liquid crystal layer at the writing position is transformed from the first preset electric field to the The second preset electric field, so that the first liquid crystal sub-unit, the second liquid crystal sub-unit and the third liquid crystal sub-unit at the writing position transform under the action of the second preset electric field into a scattering state, so that the bistable liquid crystal layer displays the color of the light-shielding substrate at the writing position.

In some embodiments, the above liquid crystal writing tablet display method further includes:

In response to the received erasure instruction, a third voltage is applied between the first transparent electrode plate and the second transparent electrode plate to apply a third preset electric field to the bistable liquid crystal layer, so that all The liquid crystal molecules in the first liquid crystal subunit, the second liquid crystal subunit and the third liquid crystal subunit transform into a vertical texture state under the action of the third preset electric field; wherein, the third liquid crystal subunit The third preset electric field is greater than the second preset electric field;

Return to the step of applying a first voltage between the first transparent electrode plate and the second transparent electrode plate, so that all the first liquid crystal sub-units, the second liquid crystal sub-unit and the third liquid crystal sub-unit The liquid crystal molecules in the liquid crystal subunit change from the vertical texture state to the planar texture state under the action of the first preset electric field, so that the bistable liquid crystal layer returns to display white.

In some embodiments, the above liquid crystal writing tablet display method further includes:

In response to the received erasing instruction, a third voltage is applied between the first sub-electrode of the first transparent electrode plate and the second sub-electrode of the second transparent electrode plate at the writing position to apply The bistable liquid crystal layer at the writing position applies a third preset electric field, so that the first liquid crystal sub-unit, the second liquid crystal sub-unit and the third liquid crystal sub-unit at the writing position The liquid crystal molecules inside transform into a vertical texture state under the action of the third preset electric field; wherein the third preset electric field is greater than the second preset electric field;

Return to the step of applying a first voltage between the first transparent electrode plate and the second transparent electrode plate, so that the first liquid crystal subunit and the second liquid crystal subunit at the writing position And the liquid crystal molecules in the third liquid crystal subunit transform from the vertical texture state to a planar texture state under the action of the first preset electric field, so that the bistable liquid crystal layer returns to display white.

In a third aspect, the present application provides a writing device, including a liquid crystal writing tablet and a writing pen as described in any one of the first aspects.

Using the above technical solutions, at least the following technical effects can be achieved:

The present application provides a liquid crystal writing board, a display method thereof, and a writing device. The liquid crystal writing board includes a first transparent substrate and a light-shielding substrate that are arranged oppositely, and a double-layered screen between the first transparent substrate and the light-shielding substrate. Stable liquid crystal layer; the bistable liquid crystal layer includes a plurality of pixel units, each pixel unit including a first liquid crystal subunit, a second liquid crystal subunit and a third liquid crystal subunit arranged side by side in a direction parallel to the first transparent substrate. Three liquid crystal sub-units, any two adjacent liquid crystal sub-units are separated by transparent spacers; the first liquid crystal sub-unit, the second liquid crystal sub-unit and the third liquid crystal sub-unit are configured to It reflects red light, green light and blue light respectively under the action of a preset electric field, and is configured to be in a scattering state under the action of a second preset electric field. By arranging three types of liquid crystal sub-units that can respectively reflect red light, green light and blue light under the action of the first preset electric field in each pixel unit of the bistable liquid crystal layer, the bistable liquid crystal layer is made in the first White is displayed under the action of the preset electric field, and each liquid crystal sub-unit is transformed into a scattering state under the action of the second preset electric field, showing the color of the light-shielding substrate. It is possible to write black or colored handwriting on a white background and display brightness and contrast. All are greatly improved, greatly improving the clarity of writing on the writing board and improving the user experience.

Description of the drawings

The accompanying drawings are used to provide a further understanding of the present application and constitute a part of the specification. They are used to explain the present application together with the following specific embodiments, but do not constitute a limitation of the present application. In the attached picture:

Figure 1 is a schematic cross-sectional structural diagram of a liquid crystal writing tablet according to an exemplary embodiment of the present application;

Figure 2 is a schematic diagram of the pixel arrangement of a liquid crystal writing tablet according to an exemplary embodiment of the present application;

Figure 3(a) is a schematic diagram of the arrangement structure of cholesteric liquid crystal molecules in a planar texture state according to an exemplary embodiment of the present application;

Figure 3(b) is a schematic diagram of the arrangement structure of cholesteric liquid crystal molecules in a focal conic texture state according to an exemplary embodiment of the present application;

Figure 3(c) is a schematic diagram of the arrangement structure of cholesteric liquid crystal molecules in a vertical texture state according to an exemplary embodiment of the present application;

Figure 4 is a schematic diagram showing the relationship between reflectivity and voltage of a liquid crystal subunit in the initial state according to an exemplary embodiment of the present application;

Figure 5 is a schematic cross-sectional structural diagram of a liquid crystal writing tablet in a writing state according to an exemplary embodiment of the present application;

Figure 6 is a schematic diagram of the relationship between reflectivity and voltage of a liquid crystal subunit in a writing state according to an exemplary embodiment of the present application;

Figure 7 is a schematic diagram of the relationship between reflectivity and voltage of a liquid crystal subunit in an erased state according to an exemplary embodiment of the present application;

In the drawings, identical parts use the same reference numerals and the drawings are not drawn to actual scale;

The reference numbers are:

11-First transparent substrate; 12-Light-shielding substrate; 121-Second transparent substrate; 122-Light-shielding layer; 13-Bistable liquid crystal layer; 131-First liquid crystal subunit; 132-Second liquid crystal subunit; 133- Third liquid crystal subunit; 134-transparent spacer; 14-first transparent electrode plate; 15-second transparent electrode plate; 16-driving unit.

Detailed ways

The embodiments of the present application will be described in detail below with reference to the accompanying drawings and examples, so that the implementation process of how the present application applies technical means to solve technical problems and achieve corresponding technical effects can be fully understood and implemented accordingly. The embodiments of the present application and various features in the embodiments can be combined with each other without conflict, and the resulting technical solutions are within the protection scope of the present application. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity. The same reference numbers refer to the same elements throughout.

It will be understood that, although the terms "first," "second," "third," etc. may be used to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections do not should be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the application.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It will also be understood that the terms "consisting of" and/or "comprising", when used in this specification, identify the presence of stated features, integers, steps, operations, elements and/or parts but do not exclude one or more others The presence or addition of features, integers, steps, operations, elements, parts, and/or groups. When used herein, the term "and/or" includes any and all combinations of the associated listed items.

In order to fully understand the present application, detailed structures and steps will be provided in the following description to illustrate the technical solutions proposed in the present application. The preferred embodiments of the present application are described in detail below. However, in addition to these detailed descriptions, the present application may also have other implementations.

The present application provides a liquid crystal writing tablet, as shown in FIG. 1 , including a first transparent substrate 11 and a light-shielding substrate 12 arranged opposite each other, and a bistable liquid crystal layer 13 located between the first transparent substrate 11 and the light-shielding substrate 12 .

Among them, the first transparent substrate 11 is provided with a first transparent electrode plate 14 on a side close to the bistable liquid crystal layer 13 .

The light-shielding substrate 12 is provided with a second transparent electrode plate 15 on a side close to the bistable liquid crystal layer 13 .

The bistable liquid crystal layer 13 includes a plurality of pixel units (not labeled in the figure). As shown in FIG. 2 , each pixel unit includes a first liquid crystal sub-unit 131 and a first liquid crystal sub-unit 131 arranged side by side in a direction parallel to the first transparent substrate 11 . The second liquid crystal sub-unit 132 and the third liquid crystal sub-unit 133 are separated by transparent spacers 134 between any two adjacent liquid crystal sub-units.

The transparent spacer 134 is disposed between two adjacent liquid crystal sub-units in the same pixel unit and between two adjacent pixel units. The transparent spacer 134 plays a blocking role without blocking the light.

In some embodiments, the width W of the orthographic projection of the first liquid crystal sub-unit 131 , the second liquid crystal sub-unit 132 and the third liquid crystal sub-unit 133 on the light-shielding substrate 12 is at least 100 μm, and the length L is at least 40 μm.

In some embodiments, correspondingly, the width W of the pixel unit is at least 100 μm, and the length L is at least 120 μm.

The first liquid crystal sub-unit 131, the second liquid crystal sub-unit 132 and the third liquid crystal sub-unit 133 are configured to respectively reflect red light, green light and blue light under the action of the first preset electric field, and are configured to reflect red light, green light and blue light under the second preset electric field. Assume that it is in a scattering state under the action of an electric field.

Under the action of the first preset electric field, the first liquid crystal sub-unit 131, the second liquid crystal sub-unit 132 and the third liquid crystal sub-unit 133 respectively reflect red light, green light and blue light, and the pixel unit displays white.

Under the action of the second preset electric field, the first liquid crystal sub-unit 131, the second liquid crystal sub-unit 132 and the third liquid crystal sub-unit 133 are in a scattering state, and the pixel unit displays the color of the light-shielding substrate 12.

In some embodiments, in the initial state of the liquid crystal writing tablet, the entire bistable liquid crystal layer 13 is under the action of the first preset electric field, and the entire bistable liquid crystal layer 13 displays white. At this time, the liquid crystal writing tablet is for writing. whiteboard.

The magnitudes of the second preset electric field and the first preset electric field depend on the voltage and distance between the first transparent electrode plate 14 and the second transparent electrode plate 15 .

In some embodiments, the second preset electric field is greater than the first preset electric field. When the bistable liquid crystal layer 13 is under the first preset electric field and the first transparent substrate 11 is away from the side of the bistable liquid crystal layer 13 (writing side) is pressed (including writing pressure by a writing pen or a user's finger), at the pressing position, the distance between the first transparent electrode plate 14 and the second transparent electrode plate 15 decreases, and the bistable liquid crystal layer 13 is pressed The electric field at the position increases and can change from the first preset electric field to the second preset electric field. The bistable liquid crystal layer 13 has the first liquid crystal sub-unit 131, the second liquid crystal sub-unit 132 and the third liquid crystal at the pressing position. The sub-unit 133 changes from the state of reflecting red light, green light and blue light to the scattering state, displays the color of the light-shielding substrate 12, and realizes writing on the white liquid crystal writing board.

In some embodiments, the liquid crystal writing pad 11 includes a touch component.

For example, the touch component may be an infrared touch component (not shown in the figure). The infrared touch component may be disposed around the first transparent substrate and used to locate the user's touch or writing position on the liquid crystal writing pad 11 .

In some embodiments, the touch component may be disposed on the side (writing side) of the first transparent substrate 11 away from the bistable liquid crystal layer 13; wherein the touch component may be a capacitive touch component or a resistive touch component.

Further, in some embodiments, the first transparent electrode plate 14 includes a plurality of first sub-electrodes (not shown in the figure) arranged in an array, and the second transparent electrode plate 15 includes a plurality of first sub-electrodes arranged in an array. Two sub-electrodes (not shown in the figure).

Further, in some embodiments, the first sub-electrode and the second sub-electrode correspond one to one.

Correspondingly, when the touch component recognizes that the writing side of the first transparent substrate 11 is touched (for example, the user's writing touch operation), the driving unit 16 can be controlled to control the first sub-electrode and the second sub-electrode at the touch position. A preset voltage is applied between the electrodes, causing the bistable liquid crystal layer 13 to generate a second preset electric field at the touch position. The first liquid crystal sub-unit 131, the second liquid crystal sub-unit 132 and the third liquid crystal at the touch position The sub-unit 133 changes from the state of reflecting red light, green light and blue light to the scattering state, displays the color of the light-shielding substrate 12, and realizes writing on the white liquid crystal writing board.

Under this writing board structure, users can perform writing operations and display handwriting on the writing board through touch, which can improve writing sensitivity.

It should be noted that in the writing board structure provided with a touch component, when the first liquid crystal sub-unit 131, the second liquid crystal sub-unit 132 and the third liquid crystal sub-unit 133 are under the action of 0 electric field, they can maintain reflection respectively. In the states of red light, green light and blue light, the magnitude of the first preset electric field may be 0, that is, the voltage applied between the first transparent electrode plate 14 and the second transparent electrode plate 15 in the initial state of displaying white. The magnitude can be 0V.

In some embodiments, the color of the light-shielding substrate 12 is configured to be the color of writing.

In some embodiments, the color of the light-shielding substrate 12 is selected from any color except white, and can be black or colored, and can be set according to actual needs.

This solution for displaying writing on a white LCD writing board greatly improves the display brightness and contrast of the writing board, greatly improves the clarity of writing on the writing board, and enhances the user experience.

In some embodiments, the materials of the first liquid crystal sub-unit 131, the second liquid crystal sub-unit 132 and the third liquid crystal sub-unit 133 include cholesteric liquid crystal with bistable properties, or can be processed through a special orientation method. Achieving bistable nematic liquid crystal.

In some embodiments, the materials of the first liquid crystal sub-unit 131, the second liquid crystal sub-unit 132 and the third liquid crystal sub-unit 133 each include cholesteric liquid crystal.

Cholesteric liquid crystal has a unique spiral arrangement. The liquid crystal molecules are layered and twisted. The molecules lie flat in each layer, and the layers are parallel to each other. In each layer, the molecules tend to be parallel to each other like the nematic phase. Arrangement, but the director of the molecules rotates basically uniformly and continuously along the normal direction of the layer. The distance between the layers when the director rotates 360° is called the pitch P0. Cholesteric liquid crystal includes planar texture state (Planar Texture, P state), focal conic texture state (Focal Conic Texture, FC state) and vertical structure state (Homeotropic, H state). Among them, the planar texture state (P state) and the focal cone texture state (FC state) can be stably maintained without voltage maintenance. As shown in Figure 3(a), when the cholesteric liquid crystal presents a planar texture state (P state), the liquid crystal molecules are arranged in a spiral shape in space around the spiral axis perpendicular to the substrate surface. When light is incident on the liquid crystal surface, the liquid crystal Molecules selectively reflect light of a specific wavelength λ. As shown in Figure 3(b), when the cholesteric liquid crystal exhibits a focal conic texture state (FC state), the liquid crystal molecules are still arranged in a spiral, but the directions of the spiral axes of the liquid crystal domains are randomly distributed, and the molecules are in a multi-domain state. Light is scattered at the junction of adjacent liquid crystal domains due to sudden changes in refractive index, and can pass through the color of the underlying substrate. There is a potential barrier with a certain height between the planar texture state (P state) and the focal cone texture state (FC state). This potential barrier can be overcome by applying an external electric field to realize the planar texture state (P state) and the focal cone texture state. The transformation of the structural state (FC state), if the cholesteric liquid crystal is initially in the planar texture state (P state), when the electric field increases to the threshold electric field (such as the second preset electric field), the planar texture state (P state) occurs. ) to the focal cone texture state (FC state). The focal cone texture state (FC state) is a stable state. Even if the electric field or voltage drops to zero, it will always maintain the focal cone texture state (FC state), further increasing the When a large external electric field reaches a saturated electric field (such as the third preset electric field, applied in the erasure mode), the focal conic texture state (FC state) changes to the vertical structure state (H state) as shown in Figure 3(c) , because the vertical structure state (H state) is not a stable state, if the voltage is quickly reduced to a certain threshold or zero, the liquid crystal transitions to the initial planar texture state (P state), and the focal conic texture state (FC state) can go to the vertical state. The structural state (H state) and then to the planar texture state (P state) can be achieved, for example, by high-voltage pulses.

Correspondingly, in this embodiment, the liquid crystal molecules in the first liquid crystal subunit 131, the second liquid crystal subunit 132 and the third liquid crystal subunit 133 are in a planar texture state (P state) under the first preset electric field. It is in the focal cone texture state (FC state) under the second preset electric field.

The first liquid crystal sub-unit 131, the second liquid crystal sub-unit 132 and the third liquid crystal sub-unit 133 use polymers to induce the formation of different liquid crystal domains. The directions of the helical axes of the liquid crystals in the domains are different, and the effective refractive index is different. In the planar texture state (P state), it can selectively reflect light of a specific wavelength λ, thereby reflecting blue light, green light and red light respectively.

Correspondingly, the transparent shield can be a polymer network, which can induce the cholesteric liquid crystal to form different liquid crystal domains and reflect light of different spectra.

Correspondingly, the bistable liquid crystal layer 13 can be prepared by forming transparent spacers 134 on the substrate, and then forming the first liquid crystal sub-unit 131, the second liquid crystal sub-unit 132 and the third liquid crystal at the corresponding positions through fine processes such as dripping. subunit 133, thereby forming a bistable liquid crystal layer 13.

Correspondingly, when the liquid crystal writing tablet is in the initial state, the entire bistable liquid crystal layer 13 is under the action of the first preset electric field, and the first liquid crystal subunit 131, the second liquid crystal subunit 132 and the third liquid crystal subunit 133 The liquid crystal molecules inside are in a planar texture state (P state) under the first preset electric field, reflecting blue light, green light and red light respectively. The entire bistable liquid crystal layer 13 shows white, and the liquid crystal writing board is a writing whiteboard at this time. .

When the bistable liquid crystal layer 13 is under the first preset electric field and the side (writing side) of the first transparent substrate 11 away from the bistable liquid crystal layer 13 is pressed (including writing pressure by a writing pen or a user's finger), At the pressing position, the distance between the first transparent electrode plate 14 and the second transparent electrode plate 15 decreases, and the electric field of the bistable liquid crystal layer 13 at the pressing position increases, which can change from the first preset electric field to the second Preset electric field, the liquid crystal molecules in the first liquid crystal sub-unit 131, the second liquid crystal sub-unit 132 and the third liquid crystal sub-unit 133 at the pressing position transform from the planar texture state (P state) to the focal conic texture state (FC). state), scattering occurs, and the bistable liquid crystal layer 13 displays the color of the light-shielding substrate 12 at the pressed position, enabling writing to be displayed on a white liquid crystal writing board.

And the focal cone texture state (FC state) is a stable state. Even if the pressure at the pressing position is reduced or disappears, the electric field received by the bistable liquid crystal layer 13 returns to the initial state (first preset electric field), and the liquid crystal writing board The handwriting will not disappear.

Correspondingly, for a writing pad structure provided with a touch component, when the liquid crystal molecules of the first liquid crystal subunit 131, the second liquid crystal subunit 132 and the third liquid crystal subunit 133 are under the action of 0 electric field, they can maintain a planar surface. In the texture state (P state), the magnitude of the first preset electric field can be 0, that is, in the initial state of displaying white, the magnitude of the voltage applied between the first transparent electrode plate 14 and the second transparent electrode plate 15 can be is 0V.

In some embodiments, the light-shielding substrate 12 includes a second transparent substrate 121 and a light-shielding layer 122 disposed between the second transparent substrate 121 and the second transparent electrode plate 15 .

In some embodiments, the material of the light shielding layer 122 may be a black matrix layer or a color photoresist layer.

In some embodiments, the material of the second transparent substrate 121 may be the same as the material of the above-mentioned first transparent substrate 11 , and may be glass or a transparent PET protective film.

In some embodiments, the material of the second transparent substrate 121 may be different from the material of the above-mentioned first transparent substrate 11. Preferably, in order to improve the writing sensitivity of the writing board, the first transparent substrate 11 may be made of polyethylene with a larger elastic modulus. Ethylene terephthalate, the second transparent substrate 121 may be made of glass.

In some embodiments, the light-shielding layer 122 is provided with a plurality of protrusions on a side close to the second transparent electrode plate 15, so that when the liquid crystal molecules of the bistable liquid crystal layer 13 are in a focal cone texture state (FC state), The light passes through the bistable liquid crystal layer 13 and the second transparent electrode plate 15, and is diffusely reflected on the side of the light shielding layer 122 close to the second transparent electrode plate 15, so that the bistable liquid crystal layer 13 displays the color of the light shielding substrate 12. More obvious, making the handwriting more obvious.

In some embodiments, the above-mentioned liquid crystal writing tablet further includes: a driving unit 16 electrically connected to the first transparent electrode plate 14 and the second transparent electrode plate 15 , and the driving unit 16 is configured to drive the first transparent electrode plate 14 and the second transparent electrode plate 15 . A voltage is applied between the transparent electrode plates 15 to apply a corresponding electric field to the bistable liquid crystal layer 13 .

In some embodiments, the driving unit 16 is configured to apply a corresponding voltage between the first transparent electrode plate 14 and the second transparent electrode plate 15 according to the user's turning on or erasing instruction, so as to apply the corresponding voltage to the bistable liquid crystal layer 13 Apply the corresponding electric field.

In some embodiments, corresponding to a writing pad structure provided with a touch component, the driving unit 16 may be configured to apply corresponding voltages between all first sub-electrodes and second sub-electrodes according to the user's erasure instruction, such that The entire bistable liquid crystal layer 13 returns to the initial state (whiteboard state), and the handwriting is erased. Alternatively, the driving unit 16 may be configured to apply a corresponding voltage between the first sub-electrode and the second sub-electrode whose voltage state is not the initial state according to the user's erasure instruction, so as to only cause the liquid crystal molecules at the position where the note is written to Restore the initialization state, and the handwriting can also be erased.

Optionally, when the touch component recognizes that the writing side of the first transparent substrate 11 is performing an erasing operation, the driving unit 16 can be controlled to load a preset voltage on the first sub-electrode and the second sub-electrode at the touch position. , causing the bistable liquid crystal layer 13 to generate a third preset electric field at the touch position. The third preset electric field is greater than the potential barrier for the cholesteric liquid crystal molecules to transform into a vertical texture state (H state). Therefore, the touch position is The liquid crystal molecules in the first liquid crystal sub-unit 131, the second liquid crystal sub-unit 132 and the third liquid crystal sub-unit 133 transform into an unstable vertical texture state (H state) under the action of the third preset electric field. Finally, when the first sub-electrode and the second sub-electrode return to the initial voltage (that is, the voltage that maintains the planar texture state of the liquid crystal molecules), the cholesteric liquid crystal molecules in the bistable liquid crystal layer 13 change from unstable vertical The texture state (H state) directly returns to the stable planar texture state (P state), so that the bistable liquid crystal layer 13 returns to display white and returns to the initial state, thereby achieving local erasure.

It can be understood that when all the liquid crystal molecules in the first liquid crystal sub-unit 131, the second liquid crystal sub-unit 132 and the third liquid crystal sub-unit 133 are acted upon by the third preset electric field at the same time or at a similar time, writing on the liquid crystal can be achieved. Overall erasure of board 11.

In this application, three types of liquid crystal sub-units that can respectively reflect red light, green light and blue light under the action of the first preset electric field are provided in each pixel unit of the bistable liquid crystal layer 13 so that the bistable liquid crystal layer 13 White is displayed under the action of the first preset electric field, and each liquid crystal sub-unit is transformed into a scattering state under the action of the second preset electric field, showing the color of the light-shielding substrate 12, enabling black or colored handwriting to be written on a white background. The display brightness and contrast have been greatly improved, which greatly improves the clarity of writing on the writing board and enhances the user experience.

This application also provides a display method for a liquid crystal writing board, including:

Step S110: Apply a first voltage between the first transparent electrode plate 14 and the second transparent electrode plate 15 to apply a first preset electric field to the bistable liquid crystal layer 13, so that the first liquid crystal subunit 131 and the second liquid crystal The subunit 132 and the third liquid crystal subunit 133 respectively reflect red light, green light and blue light under the action of the first preset electric field, so that the bistable liquid crystal layer 13 displays white under the action of the first preset electric field.

In some embodiments, when the material of the first liquid crystal sub-unit 131, the second liquid crystal sub-unit 132 and the third liquid crystal sub-unit 133 is cholesteric liquid crystal, as shown in Figure 4, in the initial state, toward the first The first voltage _Va is applied between the transparent electrode plate 14 and the second transparent electrode plate 15. At this time, the writing pad is not pressed, and the equivalent voltage at each position of the bistable liquid crystal layer 13 is _Va , and _Va remains constant. changes, and the first voltage _Va is less than or equal to the maximum voltage V _w when the bistable liquid crystal layer 13 is in the planar texture state (P state), so as to apply the first preset electric field to the bistable liquid crystal layer 13, so that the first The liquid crystal molecules in the liquid crystal subunit 131, the second liquid crystal subunit 132 and the third liquid crystal subunit 133 are all in a planar texture state (P state) under the action of the first preset electric field, reflecting red light, green light and Blue light causes the bistable liquid crystal layer 13 to display white under the action of the first preset electric field.

Since the first voltage _Va ≤ _{V w} , even if V _w is 0V and the first voltage _Va is 0V, because each liquid crystal subunit is already in a planar texture state (P state), during the voltage application period and after the voltage is removed and stabilized, , each liquid crystal subunit is always in a planar texture state (P state), and the reflectivity does not change. At this time, the reflectance is Rp, and the first liquid crystal subunit 131, the second liquid crystal subunit 132 and the third liquid crystal subunit 133 respectively reflect Red light, green light, and blue light can reflect the entire visible light and appear white.

The first voltage is applied via the drive unit 16 .

Step S120: In response to the writing operation acting on the side of the first transparent substrate 11 away from the bistable liquid crystal layer 13, the electric field of the bistable liquid crystal layer 13 at the writing position is transformed from the first preset electric field to the second preset electric field. An electric field is set so that the first liquid crystal sub-unit 131, the second liquid crystal sub-unit 132 and the third liquid crystal sub-unit 133 at the writing position transform into a scattering state under the action of the second preset electric field, thereby making the bistable liquid crystal layer 13 displays the color of the light-shielding substrate 12 at the writing position.

In some embodiments, the second preset electric field is greater than the first preset electric field. As shown in FIG. 5 , the electric field change at the writing position may be caused by the first transparent electrode plate 14 and the second transparent electrode plate 15 due to the writing pressure. When the distance between the first transparent electrode plate 14 and the second transparent electrode plate 15 decreases to the point where the electric field between them is greater than the cholesteric phase liquid crystal molecules change from the planar texture state (P state) When transitioning to the potential barrier of the focal cone texture state (FC state), that is, when the second preset electric field is used, the first liquid crystal subunit 131, the second liquid crystal subunit 132 and the third liquid crystal subunit 133 at the writing position The liquid crystal molecules transform from the planar texture state (P state) to the focal conic texture state (FC state) under the action of the second preset electric field, so that the bistable liquid crystal layer 13 displays the shape of the light-shielding substrate 12 at the writing position. color.

As shown in Figure 6, in the writing state, the voltage applied between the first transparent electrode plate 14 and the second transparent electrode plate 15 is still the first voltage Va _{= Vw} , and the bistable liquid crystal at the unwritten position The equivalent voltage of layer 13 (liquid crystal cell) is still Va ₌ V _w . The liquid crystal molecules at the unwritten position are still in the planar texture state (P state). The display color of the writing board reflects the entire visible light and appears white. The display principle The same as the initial state; when writing, pressing will cause the distance between the electrode plates at the pressed position to become smaller, thereby increasing the electric field intensity between the electrode plates. At this time, it is assumed that the equivalent voltage in the bistable liquid crystal layer 13 at the pressed position is V _f , At this time, V _f is within the range of V _K (the minimum voltage at which the cholesteric liquid crystal reaches the FC state) and V _g (the maximum voltage at which the cholesteric liquid crystal reaches the FC state). V _f varies depending on the pressing force of writing, V _K The specific values of and V _g need to be determined according to the properties of different bistable liquid crystal materials. When V _K ≤ V _f ≤ V _g , the liquid crystal molecules transform from the P state to the FC state, the reflectivity decreases, and the reflectivity decreases from Rp To Rfc, the liquid crystal subunit scatters, and the display color at the pressed position is the color of the light-shielding substrate 12, which can be black or colored. Even when the writing stops and the pressing disappears, the voltage of the bistable liquid crystal layer 13 (liquid crystal cell) at the writing position and the unwritten position returns to the original state, that is, the voltage at each position is V _a =V w , and the voltage at each position is V a =V _w . The electric field intensity at the position returns to the initial size, but because the liquid crystal molecules in the written area remain in a stable FC state, as long as the voltage does not exceed V _g , this part of the liquid crystal molecules remains in the FC state. Therefore, the color distinction between the writing position and the unwritten position is realized, and black or colored handwriting is displayed on the white writing board.

In addition, for a writing board structure provided with a touch component, in response to a writing operation acting on the side of the first transparent substrate 11 away from the bistable liquid crystal layer 13 , the driving unit 16 can be used to move the first transparent substrate 11 to the writing position. A second voltage is applied between one sub-electrode and the second sub-electrode, so that the electric field of the bistable liquid crystal layer 13 at the writing position changes from the first preset electric field to the second preset electric field, so that the first preset electric field at the writing position The liquid crystal sub-unit 131, the second liquid crystal sub-unit 132 and the third liquid crystal sub-unit 133 transform into a scattering state under the action of the second preset electric field, so that the bistable liquid crystal layer 13 displays the light shielding substrate 12 at the writing position. color.

Step S130: In response to the received erasure instruction, apply a third voltage between the first transparent electrode plate 14 and the second transparent electrode plate 15 to apply a third preset electric field to the bistable liquid crystal layer 13, so that all The liquid crystal molecules in the first liquid crystal sub-unit 131, the second liquid crystal sub-unit 132 and the third liquid crystal sub-unit 133 transform into a vertical texture state under the action of the third preset electric field; wherein the third preset electric field is greater than the second Default electric field.

The third preset electric field is greater than the potential barrier for the cholesteric liquid crystal molecules to transform into the vertical texture state (H state). When the driving unit 16 applies the third preset electric field to the bistable liquid crystal layer 13, the writing position (with writing The cholesteric liquid crystal molecules at the unwritten position (the position without handwriting) change from the focal cone texture state (FC state) to the vertical texture state (H state). The structural state (P state) first transforms into the focal conic texture state (FC state) and then into the vertical texture state (H state), but the cholesteric liquid crystal molecules directly transform from the focal conic texture state (FC state) to the vertical texture state (FC state). Whether the texture state (H state) or from the planar texture state (P state) first to the focal cone texture state (FC state) and then to the vertical texture state (H state), the transition time is very fast. The two methods can be approximately regarded as being completed at the same time.

As shown in Figure 7, when the liquid crystal writing board is in the erasing state, a third voltage V _b is applied between the first transparent electrode plate 14 and the second transparent electrode plate 15. V _b is equal to the transition of the cholesteric liquid crystal molecules into the H state. The barrier voltage V _p , where V _w < V _g < V _p , the specific value of V _p needs to be determined according to the properties of different bistable liquid crystal materials. In the erasing state, the first transparent substrate 11 is not pressed, and the first transparent substrate 11 is not pressed. The distance between the first transparent electrode plate 14 and the second transparent electrode plate 15 is in the original state, and the equivalent voltage of the bistable liquid crystal layer 13 (liquid crystal cell) is equal to V _p . At this time, the bistable liquid crystal layer is at the writing and pressing position. The liquid crystal molecules in the bistable liquid crystal layer 13 at the unwritten and pressed position first change from the P state to the FC state and then to the H state.

Step S140: Return to the step of applying the first voltage between the first transparent electrode plate 14 and the second transparent electrode plate 15 (ie step S110), so that all the first liquid crystal sub-units 131, the second liquid crystal sub-unit 132 and the third The liquid crystal molecules in the liquid crystal subunit 133 change from a vertical texture state to a planar texture state under the action of the first preset electric field, so that the bistable liquid crystal layer 13 returns to display white.

Since the vertical texture state (H state) is an unstable state, the driving unit 16 resumes applying the first voltage after applying the third voltage, so that the cholesteric liquid crystal molecules in the bistable liquid crystal layer 13 change from unstable vertical texture to The structural state (H state) directly returns to the stable planar texture state (P state), so that the bistable liquid crystal layer 13 returns to display white and returns to the initial state.

That is to say, because the H state is not a stable state, applying a pulse voltage will cause the bistable liquid crystal at the pressed position to quickly change from the FC state to the P state, and the reflectivity returns to Rp. At this time, the electronic whiteboard becomes the initial state. , the whole can reflect the entire visible light and appear white, thereby realizing the erasing function. During the erasing process, the equivalent voltage change process of the bistable liquid crystal layer 13 (liquid crystal cell) is first from V _w to V _f and then to V _p and finally to restore V _w .

In some embodiments, for a writing board structure provided with a touch component, the above erasing method can be used, or the following erasing methods can be used, including:

Step S132: In response to the received erasing instruction, a third voltage is applied between the first sub-electrode of the first transparent electrode plate 14 and the second sub-electrode of the second transparent electrode plate 15 at the writing position to apply the third voltage to the writing position. The bistable liquid crystal layer 13 at the writing position applies a third preset electric field, so that the liquid crystal molecules in the first liquid crystal subunit 131, the second liquid crystal subunit 132 and the third liquid crystal subunit 133 at the writing position are in the third preset position. Transformed into a vertical texture state (H state) under the action of an electric field; where the third preset electric field is greater than the second preset electric field;

Step S142: Return to the step of applying the first voltage between the first transparent electrode plate 14 and the second transparent electrode plate 15 (that is, step S110), so that the first liquid crystal subunit 131 and the second liquid crystal subunit 132 at the writing position The liquid crystal molecules in the third liquid crystal sub-unit 133 transform from the vertical texture state (H state) to the planar texture state (P state) under the action of the first preset electric field, so that the bistable liquid crystal layer 13 resumes display. White.

That is to say, for a writing board structure provided with a touch component, in addition to erasing the handwriting by initializing the entire surface, it is also possible to initialize only the writing position to erase the handwriting.

An embodiment of the present application also provides a writing device, including the liquid crystal writing board and writing pen described in any one of the above.

In some embodiments, the tip size of the writing pen is 1 mm to 3 mm, which is much larger than the size of the pixel unit.

The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application shall be included in the protection scope of this application. Although the embodiments disclosed in this application are as above, the contents are only used to facilitate the understanding of this application and are not intended to limit this application. Any skilled person in the technical field to which this application belongs can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in this application. However, the protection scope of this application remains The scope defined by the appended claims shall prevail.

Claims (14)

1. A liquid crystal writing tablet, characterized in that it includes: a first transparent substrate and a light-shielding substrate arranged oppositely, and a bistable liquid crystal layer located between the first transparent substrate and the light-shielding substrate; Wherein, the first transparent substrate is provided with a first transparent electrode plate on a side close to the bistable liquid crystal layer; The light-shielding substrate is provided with a second transparent electrode plate on a side close to the bistable liquid crystal layer; The bistable liquid crystal layer includes a plurality of pixel units, each pixel unit including a first liquid crystal sub-unit, a second liquid crystal sub-unit and a third liquid crystal sub-unit arranged side by side in a direction parallel to the first transparent substrate, Any two adjacent liquid crystal sub-units are separated by transparent spacers; The first liquid crystal sub-unit, the second liquid crystal sub-unit and the third liquid crystal sub-unit are configured to respectively reflect red light, green light and blue light under the action of a first preset electric field, and are configured to It is in a scattering state under the action of the second preset electric field; The second preset electric field is greater than the first preset electric field; When the bistable liquid crystal layer is under the first preset electric field and the side of the first transparent substrate away from the bistable liquid crystal layer is pressed, the bistable liquid crystal layer is at the pressed position. The electric field is transformed from the first preset electric field to the second preset electric field. 2. The liquid crystal writing tablet according to claim 1, wherein the liquid crystal writing tablet further comprises a touch component. 3. The liquid crystal writing tablet according to claim 2, wherein the first transparent electrode plate includes a plurality of first sub-electrodes arranged in an array; The second transparent electrode plate includes a plurality of second sub-electrodes arranged in an array. 4. The liquid crystal writing tablet according to claim 1, wherein the color of the light-shielding substrate is configured to be the color of writing handwriting. 5. The liquid crystal writing tablet according to claim 4, wherein the color of the light-shielding substrate is selected from any color except white. 6. The liquid crystal writing tablet according to claim 1, wherein the materials of the first liquid crystal sub-unit, the second liquid crystal sub-unit and the third liquid crystal sub-unit all include cholesteric liquid crystal. 7. The liquid crystal writing tablet according to claim 6, wherein the liquid crystal molecules in the first liquid crystal subunit, the second liquid crystal subunit and the third liquid crystal subunit are in the first preset state. It is assumed that it is in a planar texture state under an electric field and is in a focal conic texture state under the second preset electric field. 8. The liquid crystal writing tablet according to claim 1, wherein the light-shielding substrate includes a second transparent substrate, and a light-shielding layer disposed between the second transparent substrate and the second transparent electrode plate. 9. The liquid crystal writing tablet according to claim 8, wherein the light-shielding layer is provided with a plurality of protrusions on a side close to the second transparent electrode plate. 10. The liquid crystal writing tablet according to claim 1, further comprising: a driving unit electrically connected to the first transparent electrode plate and the second transparent electrode plate, the driving unit being configured to apply a voltage between the first transparent electrode plate and the second transparent electrode plate, To apply a corresponding electric field to the bistable liquid crystal layer. 11. A display method for a liquid crystal writing board according to any one of claims 1 to 10, characterized in that it includes: A first voltage is applied between the first transparent electrode plate and the second transparent electrode plate to apply the first preset electric field to the bistable liquid crystal layer, so that the first liquid crystal subunit, The second liquid crystal subunit and the third liquid crystal subunit respectively reflect red light, green light and blue light under the action of the first preset electric field, so that the bistable liquid crystal layer is in the first preset electric field. Displays white under the action of the preset electric field; In response to a writing operation acting on the side of the first transparent substrate away from the bistable liquid crystal layer, the electric field of the bistable liquid crystal layer at the writing position is transformed from the first preset electric field to the The second preset electric field, so that the first liquid crystal sub-unit, the second liquid crystal sub-unit and the third liquid crystal sub-unit at the writing position transform under the action of the second preset electric field into a scattering state, so that the bistable liquid crystal layer displays the color of the light-shielding substrate at the writing position. 12. The method for displaying a liquid crystal writing tablet according to claim 11, further comprising: In response to the received erasure instruction, a third voltage is applied between the first transparent electrode plate and the second transparent electrode plate to apply a third preset electric field to the bistable liquid crystal layer, so that all The liquid crystal molecules in the first liquid crystal subunit, the second liquid crystal subunit and the third liquid crystal subunit transform into a vertical texture state under the action of the third preset electric field; wherein, the third liquid crystal subunit The third preset electric field is greater than the second preset electric field; Return to the step of applying a first voltage between the first transparent electrode plate and the second transparent electrode plate, so that all the first liquid crystal sub-units, the second liquid crystal sub-unit and the third liquid crystal sub-unit The liquid crystal molecules in the liquid crystal subunit change from the vertical texture state to the planar texture state under the action of the first preset electric field, so that the bistable liquid crystal layer returns to display white. 13. The display method of the liquid crystal writing tablet according to claim 11, further comprising: In response to the received erasing instruction, a third voltage is applied between the first sub-electrode of the first transparent electrode plate and the second sub-electrode of the second transparent electrode plate at the writing position to apply The bistable liquid crystal layer at the writing position applies a third preset electric field, so that the first liquid crystal sub-unit, the second liquid crystal sub-unit and the third liquid crystal sub-unit at the writing position The liquid crystal molecules inside transform into a vertical texture state under the action of the third preset electric field; wherein the third preset electric field is greater than the second preset electric field; Return to the step of applying a first voltage between the first transparent electrode plate and the second transparent electrode plate, so that the first liquid crystal subunit and the second liquid crystal subunit at the writing position And the liquid crystal molecules in the third liquid crystal subunit transform from the vertical texture state to a planar texture state under the action of the first preset electric field, so that the bistable liquid crystal layer returns to display white. 14. A writing device, characterized by comprising the liquid crystal writing board and writing pen according to any one of claims 1 to 10.