Electronic handwriting board

Abstract

The embodiment of the utility model discloses an electronic handwriting board. The electronic handwriting board comprises a handwriting panel, an erasing module and a control module, the handwriting panel comprises a color substrate, a first conductive layer, a bistable liquid crystal layer, a second conductive layer and a cover plate, the first conductive layer, the bistable liquid crystal layer, the second conductive layer and the cover plate are sequentially stacked on the color substrate; the first conductive layer, the second conductive layer and the erasing module are all connected with the control module, the erasing module is used for generating an erasing signal, and the control module is used for applying an erasing voltage to the handwriting panel according to the erasing signal so as to erase a picture displayed on the handwriting panel. According to the scheme, the production cost of the electronic handwriting board can be reduced, and the display color purity is improved.

Description

Technical Field

[0001] This utility model relates to the field of display panel technology, and in particular to an electronic handwriting tablet. Background Technology

[0002] Currently, due to the requirements of liquid crystal pitch, bistable liquid crystal display technology generally only supports monochrome or black-and-white displays with a single-cell architecture. If color display is required, a three-layer liquid crystal cell architecture is needed, with different colors of bistable liquid crystal injected at different locations to achieve color pattern display. This approach is characterized by complex manufacturing processes, high costs, and low color purity. Utility Model Content

[0003] This utility model provides an electronic handwriting tablet to reduce the production cost of the electronic handwriting tablet and improve the purity of the displayed colors.

[0004] This utility model provides an electronic handwriting tablet, which includes a handwriting panel, an erasing module, and a control module;

[0005] The handwriting panel includes a color substrate, a first conductive layer, a bistable liquid crystal layer, a second conductive layer, and a cover plate;

[0006] The first conductive layer, the bistable liquid crystal layer, the second conductive layer, and the cover plate are sequentially stacked on the color substrate;

[0007] The first conductive layer, the second conductive layer, and the erasure module are all connected to the control module. The erasure module is used to generate an erasure signal, and the control module is used to apply an erasure voltage to the handwriting panel according to the erasure signal to erase the display screen of the handwriting panel.

[0008] Optionally, the average refractive index of the bistable liquid crystal layer is 1.6;

[0009] The bistable liquid crystal layer includes bistable liquid crystals with a helical pitch greater than 500 nm or less than 250 nm.

[0010] Optionally, the thickness of the bistable liquid crystal layer is an integer multiple of the helical pitch of the bistable liquid crystal.

[0011] Optionally, the color substrate includes a color resist layer, a reflective layer, and a first substrate;

[0012] The color resist layer is disposed on the side of the first conductive layer away from the bistable liquid crystal layer;

[0013] The reflective layer is disposed between the color resist layer and the first substrate; or, the first substrate is disposed between the color resist layer and the reflective layer.

[0014] Optionally, the color resist layer includes at least one color.

[0015] Optionally, the reflective layer may include a metallic reflective layer or a white base plate.

[0016] Optionally, the color substrate includes a second substrate and a removable substrate;

[0017] The second substrate is disposed on the side of the first conductive layer away from the bistable liquid crystal layer, and the removable substrate is disposed on the side of the second substrate away from the first conductive layer;

[0018] The removable substrate includes at least one color.

[0019] Optionally, the second conductive layer includes at least one conductive region;

[0020] The erasure module includes at least one erasure button;

[0021] Each of the erase buttons is connected to at least one of the conductive areas.

[0022] Optionally, the erasure voltage includes a first-stage pulse voltage, a second-stage pulse voltage, and a third-stage voltage;

[0023] The first-stage pulse voltage is used to drive the bistable liquid crystal layer to switch from the P-plane textured state or the FC focal cone state to the H-field nematic phase state;

[0024] The second-stage pulse voltage and the third-stage voltage are used to drive the bistable liquid crystal layer to switch from the H-field nematic phase state to the FC focal cone state.

[0025] Optionally, the first stage pulse voltage is ±20V-±30V, the second stage pulse voltage is ±10V-±15V, and the third stage voltage is 0V.

[0026] This invention's handwriting panel is based on the characteristics of a bistable liquid crystal layer. A control module applies pulse voltages to the first and second conductive layers, causing the bistable liquid crystal layer to change from a P-plane textured state to an FC focal conic state, resulting in a bistable liquid crystal layer entirely composed of FC focal conic states. Through localized external force, the bistable liquid crystal layer, previously entirely composed of FC focal conic states, is transformed into a bistable liquid crystal layer simultaneously comprising both FC focal conic and P-plane textured states. The P-plane textured bistable liquid crystal reflects the color of the color substrate to display a color pattern. By applying a large voltage to the first and second conductive layers and gradually decreasing the voltage, the color pattern reflected by the P-plane textured bistable liquid crystal is erased. Therefore, compared to existing technologies that use bistable liquid crystals of different colors injected at different locations to display color patterns, this solution offers advantages such as low cost and high color purity. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A schematic diagram of the structure of an electronic handwriting tablet provided in an embodiment of this utility model;

[0029] Figure 2 A cross-sectional view of a handwriting panel provided in an embodiment of this utility model;

[0030] Figure 3 A helical structure for a bistable liquid crystal provided in this embodiment of the present invention;

[0031] Figure 4 A schematic diagram of the state transition of a bistable liquid crystal layer 130 provided in an embodiment of this utility model;

[0032] Figure 5 A cross-sectional view of another handwriting panel provided in an embodiment of this utility model;

[0033] Figure 6 A cross-sectional view of another handwriting panel provided in an embodiment of this utility model;

[0034] Figure 7 A cross-sectional view of another handwriting panel provided in an embodiment of this utility model;

[0035] Figure 8 A cross-sectional view of another handwriting panel provided in an embodiment of this utility model;

[0036] Figure 9 This is a schematic diagram of an erase signal provided in an embodiment of the present invention. Detailed Implementation

[0037] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0038] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0039] Figure 1 This is a schematic diagram of the structure of an electronic handwriting tablet provided in an embodiment of the present invention. Figure 2 This is a cross-sectional view of a handwriting panel provided in an embodiment of the present utility model. Figure 1 and Figure 2 As shown, the electronic handwriting tablet includes a handwriting panel 100, an erasing module 200, and a control module 300;

[0040] The handwriting panel 100 includes a color substrate 110, a first conductive layer 120, a bistable liquid crystal layer 130, a second conductive layer 140, and a cover plate 150; the first conductive layer 120, the bistable liquid crystal layer 130, the second conductive layer 140, and the cover plate 150 are sequentially stacked on the color substrate 110.

[0041] The first conductive layer 120, the second conductive layer 140, and the erasure module 200 are all connected to the control module 300. The erasure module 200 is used to generate an erasure signal, and the control module 300 is used to apply an erasure voltage to the handwriting panel 100 according to the erasure signal to erase the display screen of the handwriting panel 100.

[0042] The bistable liquid crystal layer 130 is a layered structure composed of multiple layers of bistable liquid crystals. The bistable liquid crystals are flat and have a periodic helical structure, with their major axis parallel to the layer plane. By changing the pitch of their helical spirals, they can selectively reflect light of different wavelengths, thereby changing the color of the reflected light. For example, Figure 3 A helical structure for a bistable liquid crystal is provided in this embodiment of the present invention.

[0043] The control module 300 can apply different voltages to the first conductive layer 120 and the second conductive layer 140 to cause the bistable liquid crystal layer 130 to change between the P-plane textured state (stable state), the FC focal cone state (stable state), and the H-field nematic phase state (non-stable state). For example, Figure 4 A schematic diagram of the state transition of a bistable liquid crystal layer 130 provided for an embodiment of this utility model is shown below. Figure 4 As shown, when the control module 300 provides a pulse voltage to the first conductive layer 120 and the second conductive layer 140, the bistable liquid crystal layer 130 will change from the P-plane textured state to the FC focal conic state. When the bistable liquid crystal layer 130 in the FC focal conic state is pressed by an external force, it will change from the FC focal conic state to the P-plane textured state. When the control module 300 provides a large voltage to the first conductive layer 120 and the second conductive layer 140, the bistable liquid crystal layer 130 will change from the P-plane textured state or the FC focal conic state to the H-field nematic phase state. When the control module 300 rapidly de-energizes the first conductive layer 120 and the second conductive layer 140 (e.g., by directly changing the voltage from 30V to 0V), the bistable liquid crystal layer 130 will change from the H-field nematic phase state to the P-plane textured state. When the control module 300 slowly de-energizes the first conductive layer 120 and the second conductive layer 140 (for example, by gradually reducing the voltage directly from 20V to 0V), the bistable liquid crystal layer 130 will change from the H-field nematic phase state to the FC focal cone state.

[0044] Furthermore, the p-planar textured bistable liquid crystal layer 130 has the following characteristics: when the wavelength of the incident light matches the pitch of the bistable liquid crystal, the incident light of a specific wavelength is strongly reflected, while light of other wavelengths is transmitted through the bistable liquid crystal layer 130. Thus, the bistable liquid crystal can exhibit bright colors and has high reflectivity and contrast. The bistable liquid crystal is flat and arranged in layers, with the bistable liquid crystals within each layer parallel to each other. The long axis of the bistable liquid crystal is parallel to the layer plane, and the arrangement direction of the multiple layers of bistable liquid crystals gradually twists into a spiral, forming a spiral structure arranged along the normal direction of the layer. The p-planar textured state is the lowest energy state of the bistable liquid crystal. In this state, the arrangement of the bistable liquid crystal is relatively ordered, and the system energy is relatively stable. Therefore, the p-planar textured state of the bistable liquid crystal can exist stably for a long time without the action of an external electric field.

[0045] The FC focal conic state bistable liquid crystal layer 130 has the following characteristics: the pitch distribution of the bistable liquid crystal is disordered, and light entering it is diffusely reflected, resulting in a blurry and opaque appearance. The bistable liquid crystal is randomly arranged within the layer, and its long axis no longer has a regular orientation. The FC focal conic state is a relatively high-energy state of the bistable liquid crystal. In this state, the bistable liquid crystal is relatively unstable and, under the influence of external pressure and other factors, it will transform from the FC focal conic state to the P-planar textured state.

[0046] The H-field nematic phase state has the following characteristics: the bistable liquid crystals become more ordered, reducing the scattering of light and making the bistable liquid crystal layer 130 transparent, allowing light to pass through it relatively easily. The bistable liquid crystal layer 130 in the H-field nematic phase state is unstable and will return to the FC focal cone state as the voltage gradually decreases.

[0047] As explained above, the control module 300 can apply different voltages to the first conductive layer 120 and the second conductive layer 140, causing the bistable liquid crystal layer 130 to change between the P-plane textured state (stable state), the FC focal conic state (stable state), and the H-field nematic phase state (non-stable state). Therefore, the control module can erase the pattern displayed on the electronic handwriting pad (the bistable liquid crystal layer 130 includes bistable liquid crystals in the FC focal conic state and the P-plane textured state) by applying a large voltage to the first conductive layer 120 and the second conductive layer 140 and gradually decreasing the voltage. Clearly, the erasure signal generated by the erasure module 200 can cause the control module 300 to apply a large voltage to the handwriting panel 100 and gradually decrease the voltage.

[0048] Furthermore, the bistable liquid crystal layer 130 in this design can reflect the colors of the color substrate 110 in the P-plane textured state, allowing the display pattern of the electronic handwriting tablet to be presented in color. The cover plate 150 includes a substrate made of transparent materials such as glass or acrylic.

[0049] The handwriting panel 100 designed in this embodiment of the invention is based on the characteristics of the bistable liquid crystal layer 130. A pulse voltage is applied to the first conductive layer 120 and the second conductive layer 140 by the control module 300, causing the bistable liquid crystal layer 130 to change from a P-plane textured state to an FC focal conic state, thus achieving a bistable liquid crystal layer 130 entirely in the FC focal conic state. Through localized external force, the bistable liquid crystal layer 130, which is entirely in the FC focal conic state, is transformed into a bistable liquid crystal layer 130 that simultaneously includes both the FC focal conic state and the P-plane textured state. The color pattern is displayed by reflecting the color of the color substrate 110 through the P-plane textured bistable liquid crystal. By applying a large voltage to the first conductive layer 120 and the second conductive layer 140 and then gradually decreasing the voltage, the color pattern reflected by the color of the color substrate 110 through the P-plane textured bistable liquid crystal is erased. Therefore, compared with the existing technology of injecting different colors into bistable liquid crystal display color patterns at different positions, this solution has the advantages of low cost and high color purity.

[0050] Based on the above embodiments, optionally, the average refractive index of the bistable liquid crystal layer 130 is 1.6; the helical pitch of the bistable liquid crystal included in the bistable liquid crystal layer 130 is greater than 500 nm or less than 250 nm.

[0051] In this case, the helical pitch of the bistable liquid crystal is greater than 500 nm or less than 250 nm, and the average refractive index of the bistable liquid crystal layer 130 is 1.6. This allows the wavelength of the reflected light from the P-plane textured bistable liquid crystal to be non-visible, with a reflected light wavelength <400 nm or >800 nm. This makes the P-plane textured bistable liquid crystal appear transparent, while applying a pulse voltage transforms it into an FC focal conic state, resulting in a milky white, hazy state. This provides users with a writing experience for color images on a white background.

[0052] Based on the above embodiments, optionally, the thickness of the bistable liquid crystal layer 130 is an integer multiple of the helical pitch of the bistable liquid crystal.

[0053] The thickness of the bistable liquid crystal layer 130 affects the filling performance, response time, and power consumption of the liquid crystal cell. A smaller bistable liquid crystal layer 130 thickness typically requires a higher voltage to drive the orientation change of the bistable liquid crystal, thus increasing power consumption. Simultaneously, an excessively small bistable liquid crystal layer 130 thickness also increases the difficulty of filling the liquid crystal cell, easily leading to uneven filling. Therefore, setting the thickness of the bistable liquid crystal layer 130 to an integer multiple of the helical pitch of the bistable liquid crystal reduces the filling difficulty, enabling the bistable liquid crystal layer 130 to produce stable Bragg reflection and achieve good display results.

[0054] Based on the above embodiments, optionally, Figure 5A cross-sectional view of another handwriting panel provided in this embodiment of the utility model. Figure 6 A cross-sectional view of another handwriting panel provided in an embodiment of this utility model. (See figure) Figure 5 and Figure 6 As shown, the color substrate 110 includes a color resist layer 111, a reflective layer 112, and a first substrate 113;

[0055] The color resist layer 111 is disposed on the side of the first conductive layer 120 away from the bistable liquid crystal layer 130; the reflective layer 112 is disposed between the color resist layer 111 and the first substrate 113; or, the first substrate 113 is disposed between the color resist layer 111 and the reflective layer 112.

[0056] Among them, the color resist layer 111 is a colored photoresist layer, which uses different colored photoresist layers to absorb or reflect light of specific wavelengths, thereby realizing color display. The color resist layer 111 has the characteristics of high resolution and high color purity, which can achieve more detailed image display and more accurate color reproduction.

[0057] The reflective layer 112 can reflect incident ambient light, allowing the handwriting panel 100 to display the image without a backlight, utilizing ambient light. The stronger the ambient light, the brighter the displayed image.

[0058] The first substrate 113 includes a substrate made of transparent materials such as glass or acrylic.

[0059] Based on the above embodiments, the reflective layer 112 may optionally include a metallic reflective layer or a white base plate.

[0060] The metallic reflective layer and white base plate can reflect visible light of all wavelengths, thereby further enhancing the brightness of the display and improving the purity of the colors.

[0061] Optionally, based on the above embodiments, the color resist layer 111 includes at least one color.

[0062] The color group layer can include one or more colors, which can be set as needed. This solution does not impose specific limitations on this.

[0063] Based on the above embodiments, optionally, Figure 7 A cross-sectional view of another handwriting panel provided in an embodiment of this utility model. (See figure) Figure 7 As shown, the color substrate 110 includes a second substrate 114 and a removable substrate 115; the second substrate 114 is disposed on the side of the first conductive layer 120 away from the bistable liquid crystal layer 130, and the removable substrate 115 is disposed on the side of the second substrate 114 away from the first conductive layer 120; the removable substrate 115 includes at least one color.

[0064] The removable substrate 115 can be freely removed, and users can install the substrate of the desired color according to their color requirements so that the handwriting panel 100 can display the desired color pattern.

[0065] Based on the above embodiments, optionally, Figure 8 A cross-sectional view of another handwriting panel provided in an embodiment of this utility model. (See figure) Figure 8 As shown, the second conductive layer 140 includes at least one conductive area 121; the erasure module 200 includes at least one erasure button; each erasure button is connected to at least one conductive area.

[0066] In cases where the electronic handwriting tablet has multiple erase buttons, different erase buttons can erase the display screen of different areas of the handwriting panel 100 through the control module 300. Thus, users can erase the display screen of part of the display area as needed, without having to erase the entire display screen.

[0067] Based on the above embodiments, optionally, Figure 9 This is a schematic diagram of an erase signal provided for an embodiment of the present invention. Figure 9 As shown, the erasure voltage includes a first-stage pulse voltage, a second-stage pulse voltage, and a third-stage voltage;

[0068] The first-stage pulse voltage is used to drive the bistable liquid crystal layer 130 to switch from the P-plane textured state or the FC focal cone state to the H-field nematic phase state;

[0069] The second-stage pulse voltage and the third-stage voltage are used to drive the bistable liquid crystal layer 130 to switch from the H-field nematic phase state to the FC focal cone state.

[0070] Specifically, the control module 300 continuously applies a voltage of 0V to the second conductive layer 140, applies a voltage of ±20V to ±30V to the first conductive layer 120 in the first stage, applies a voltage of ±10V to ±15V to the first conductive layer 120 in the second stage, and applies a voltage of 0V to the first conductive layer 120 in the third stage.

[0071] Based on the above embodiments, optionally, the first stage pulse voltage is ±20V-±30V, the second stage pulse voltage is ±10V-±15V, and the third stage voltage is 0V.

[0072] The pulse voltage in the second stage can be half of the pulse voltage in the first stage.

[0073] It should be understood that the various forms of the process shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this utility model can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this utility model can be achieved, and this is not limited herein.

[0074] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. An electronic handwriting pad, characterized by The handwriting panel, the erasing module and the control module are included. The handwriting panel includes a color substrate, a first conductive layer, a bistable liquid crystal layer, a second conductive layer and a cover plate. The first conductive layer, the bistable liquid crystal layer, the second conductive layer and the cover plate are sequentially stacked on the color substrate. The first conductive layer, the second conductive layer and the erasing module are connected with the control module, the erasing module is used to generate an erasing signal, and the control module is used to apply an erasing voltage to the handwriting panel according to the erasing signal to erase the display picture of the handwriting panel.

2. The electronic handwriting pad of claim 1, wherein, The average refractive index of the bistable liquid crystal layer is 1.

6. The bistable liquid crystal layer includes a bistable liquid crystal with a helical pitch greater than 500 nm or less than 250 nm.

3. The electronic handwriting pad of claim 2, wherein, The thickness of the bistable liquid crystal layer is an integer multiple of the helical pitch of the bistable liquid crystal.

4. The electronic handwriting pad of claim 1, wherein, The color substrate includes a color resist layer, a reflective layer and a first substrate. The color resist layer is arranged on the side of the first conductive layer away from the bistable liquid crystal layer. The reflective layer is arranged between the color resist layer and the first substrate, or the first substrate is arranged between the color resist layer and the reflective layer.

5. The electronic handwriting pad of claim 4, wherein, The color resist layer includes at least one color.

6. The electronic handwriting pad of claim 4, wherein, The reflective layer includes a metal reflective layer or a white substrate.

7. The electronic handwriting pad of claim 1, wherein, The color substrate includes a second substrate and a detachable substrate. The second substrate is arranged on the side of the first conductive layer away from the bistable liquid crystal layer, and the detachable substrate is arranged on the side of the second substrate away from the first conductive layer. The detachable substrate includes at least one color.

8. The electronic handwriting pad of claim 1, wherein, The second conductive layer includes at least one conductive area. The erasing module includes at least one erasing button. Each erasing button is connected with at least one conductive area.

9. The electronic handwriting pad of claim 1, wherein, The erasing voltage includes a first stage pulse voltage, a second stage pulse voltage and a third stage voltage. The first stage pulse voltage is used to drive the bistable liquid crystal layer to switch from a P plane texture state or a FC focal conic state to an H field nematic phase state. The second stage pulse voltage and the third stage voltage are used to drive the bistable liquid crystal layer to switch from the H field nematic phase state to the FC focal conic state.

10. The electronic handwriting pad of claim 9, wherein, The first stage pulse voltage is ±20V-±30V, the second stage pulse voltage is ±10V-±15V, and the third stage voltage is 0V.

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