Liquid crystal handwriting board

Patent metadata

Field	Value
Publication number	US-12366783-B2
Application number	US-202318698331-A
Country	US
Kind code	B2
Filing date	May 24, 2023
Priority date	May 31, 2022
Publication date	Jul 22, 2025
Grant date	Jul 22, 2025

Abstract

A liquid crystal handwriting board is provided. The liquid crystal handwriting board includes a first substrate and a second substrate that are disposed opposite to each other, and a liquid crystal layer disposed between the first substrate and the second substrate; wherein the first substrate includes: a first base substrate, and a transistor and a pixel electrode disposed at a side, proximal to the second substrate, of the first base substrate, the transistor being electrically connected to the pixel electrode; wherein the transistor includes a channel region, wherein a ratio of an area of the channel region to an on-current of the transistor is greater than a ratio of an area of a channel region of a reference transistor to an on-current of the reference transistor.

First claim

The invention claimed is:

1. A liquid crystal handwriting board, comprising: a first substrate and a second substrate that are disposed opposite to each other, and a liquid crystal layer disposed between the first substrate and the second substrate, the liquid crystal layer comprising bistable liquid crystal molecules;
wherein the first substrate comprises: a first base substrate, and a transistor and a pixel electrode disposed at a side, proximal to the second substrate, of the first base substrate, the transistor being electrically connected to the pixel electrode;
wherein the transistor comprises a channel region, wherein a ratio of an area of the channel region to an on-current of the transistor is greater than a ratio of an area of a channel region of a reference transistor to an on-current of the reference transistor, the ratio of the area of the channel region of the reference transistor to the on-current of the reference transistor being 32.5.

2. The liquid crystal handwriting board according to claim 1 , wherein a length of the channel region of the transistor is N times a length of the channel region of the reference transistor, and a width of the channel region of the transistor is N times a width of the channel region of the reference transistor, wherein N is greater than one.

3. The liquid crystal handwriting board according to claim 2 , wherein N is less than or equal to two.

4. The liquid crystal handwriting board according to claim 1 , wherein the channel region of the transistor comprises: a first sub-channel region and a second sub-channel region that are connected to each other, a length of the first sub-channel region is greater than a length of the second sub-channel region;
wherein the length of the second sub-channel region is equal to a length of the channel region of the reference transistor; and a sum of a width-to-length ratio of the first sub-channel region and a width-to-length ratio of the second sub-channel region is equal to a width-to-length ratio of the reference transistor.

5. The liquid crystal handwriting board according to claim 4 , wherein the channel region of the transistor is U-shaped, one of the first sub-channel region and the second sub-channel region comprises two sub-channel regions, and the two sub-channel regions are arranged at two sides of the other one of the first sub-channel region and the second sub-channel region.

6. The liquid crystal handwriting board according to claim 5 , wherein the two sub-channel regions are both strip-shaped, and the other one of the first sub-channel region and the second sub-channel region is U-shaped.

7. The liquid crystal handwriting board according to claim 4 , wherein a width W 1 of the first sub-channel and a width W 2 of the second sub-channel region satisfy the following relationship:
W 1/ M+W 2= W 3,
wherein W 3 represents a width of the channel region of the reference transistor, and M represents a ratio of the length of the first sub-channel region to the length of the channel region of the reference transistor, wherein M is greater than one.

8. The liquid crystal handwriting board according to claim 1 , wherein the transistor comprises: K first sub-transistors connected in series, wherein each of the first sub-transistors comprises a third sub-channel region, and the K third sub-channel regions are separately disposed, K being an integer greater than one;
wherein a length of the third sub-channel region is equal to a length of the channel region of the reference transistor, and a width of the third sub-channel region is K times a width of the channel region of the reference transistor.

9. The liquid crystal handwriting board according to claim 8 , wherein each of the third sub-channel regions is strip-shaped.

10. The liquid crystal handwriting board according to claim 1 , wherein the channel region of the transistor is annular, a length of the channel region of the transistor is equal to a length of the channel region of the reference transistor, and a width of the channel region of the transistor is equal to a width of the channel region of the reference transistor.

11. The liquid crystal handwriting board according to claim 10 , wherein the channel region of the transistor is shaped as a square annular.

12. The liquid crystal handwriting board according to claim 1 , wherein the transistor comprises: J second sub-transistors connected in parallel, wherein each of the second sub-transistors comprises an annular fourth sub-channel region, and the J fourth sub-channel regions are separately disposed, J being an integer greater than one;
wherein a length of the fourth sub-channel region is equal to a length of the channel region of the reference transistor, and a sum of widths of the J fourth sub-channel regions is equal to a width of the channel region of the reference transistor.

13. The liquid crystal handwriting board according to claim 12 , wherein the fourth sub-channel regions are equal in area, and the width of each of the fourth sub-channel regions is 1/J of the width of the channel region of the reference transistor.

14. The liquid crystal handwriting board according to claim 12 , wherein the fourth sub-channel region is shaped as a square annular.

15. The liquid crystal handwriting board according to claim 1 , wherein the on-current of the transistor has a same magnitude as the on-current of the reference transistor.

16. The liquid crystal handwriting board according to claim 1 , wherein the first substrate further comprises: a gate line and a data line, wherein the gate line is electrically connected to a gate electrode of the transistor, and the data line is electrically connected to a first electrode of the transistor, wherein a second electrode of the transistor is electrically connected to the pixel electrode.

17. The liquid crystal handwriting board according to claim 16 , wherein the second substrate comprises: a second base substrate and a common electrode disposed at a side, proximal to the first substrate, of the second base substrate, wherein one of the first base substrate and the second base substrate is a flexible base substrate; and
the transistor is configured to: be turned on upon irradiation of target light, enable the data line connected to the transistor to apply a pixel voltage to the pixel electrode connected to the transistor, and thus create a voltage difference between the pixel electrode to which the pixel voltage is applied and the common electrode.

18. The liquid crystal handwriting board according to claim 17 , wherein the flexible base substrate is disposed at a writing side of the liquid crystal handwriting board.

19. The liquid crystal handwriting board according to claim 1 , wherein a difference value between the ratio of the area of the channel region of the transistor to the on-current of the transistor and the ratio of the area of the channel region of the reference transistor to the on-current of the reference transistor is greater than or equal to 1.8.

20. The liquid crystal handwriting board according to claim 19 , wherein the difference value between the ratio of the area of the channel region of the transistor to the on-current of the transistor and the ratio of the area of the channel region of the reference transistor to the on-current of the reference transistor is less than or equal to 80.

Assignees

• Beijing Boe Optoelectronics Tech Co Ltd
• Boe Technology Group Co Ltd
• Shandong Lanbeisite Educational Equipment Group

Inventors

• Zhao Yu
• Wu Xiaojuan
• Feng Dawei
• Yu Zhiqiang
• Ge Yang
• Wang Jiaxing
• Bi Yao
• Yang Mengxun
• Wang Jian
• Wang Xiuliang
• Han Tianyang

Classifications

• G02F1/1391

  Bistable or multi-stable liquid crystal cells (G02F1/141 takes precedence) · CPC title

• G02F1/13624

  having more than one switching element per pixel · CPC title

• G02F1/13338

  Input devices, e.g. touch panels · CPC title

• G02F1/133305

  Flexible substrates, e.g. plastics, organic film · CPC title

• G02F1/13

  based on liquid crystals, e.g. single liquid crystal display cells · CPC title