LCD and touch-control method thereof

• US 7,379,054 B2
• Filed: 07/17/2003
• Issued: 05/27/2008
• Est. Priority Date: 07/18/2002
• Status: Expired due to Fees

• Current Assignee: Gigno Technology Co., Ltd.
• Original Assignee: Gigno Technology Co., Ltd.
• Inventors: Lee, Yu-Tuan
• Primary Examiner(s): Awad; Amr A.
• Assistant Examiner(s): Sherman; Stephen G.
• Application Number:
  US10/620,455
• Publication Number:
  US 20040150629A1
• Time in Patent Office: 1,776 Days
• Field of Search: 345173-178, 345/104, 178 1801- 1811, 200512-517, 3404071-4072
• US Class Current: 345/173
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells

Abstract

A touch-control method of an LCD is provided. During the idling time in-between the writing periods, the first touch-position sensing step detects the values of liquid crystal capacitances formed between the scan lines and the counter electrode, and detects a scan-line-direction touch position (Y) according to the values of the liquid crystal capacitances formed between the scan lines and the counter electrode. The charging step charges a voltage signal into each of the data lines needed to be detected after the scan-line-direction touch position (Y) is detected. After the voltage signal is charged, the second touch-position sensing step detects the values of liquid crystal capacitance formed between the data lines and the counter electrode, and detects a data-line-direction touch position (X) according to the values of the liquid crystal capacitance formed between the data lines and the counter electrode.

Claims

1. A touch-control method of an LCD, which is to sense a touch point on an LCD screen of the LCD when a pressure is applied to the LCD screen, the LCD comprising a counter electrode and a substrate having a plurality of data lines and a plurality of scan lines and a plurality of pixels, wherein the scan lines are connected to a gate of a TFT in each respective pixel, and the data lines are connected to a source of the TFT in each respective pixel, the method comprising:

a first touch-position sensing step, which detects values of liquid crystal capacitances formed between the scan lines needed to be detected and the counter electrode, respectively, and detects a scan-line-direction touch position according to the values of the liquid crystal capacitances formed between the scan lines needed to be detected and the counter electrode during idling time in-between writing periods, each of the scan lines turning on sequentially to write image data into the LCD screen in the writing periods, wherein a part of the counter electrode corresponding to the pressure is indented, the distance between the part of the counter electrode and scan line is reduced, and the distance between the part of the counter electrode and data line is reduced;

a charging step, which charges a voltage signal into each of the data lines needed to be detected after the scan-line-direction touch position is detected; and

a second touch-position sensing step, which detects values of liquid crystal capacitances formed between the data lines needed to be detected and the counter electrode, respectively, and detects a data-line-direction touch position according to the values of the liquid crystal capacitances formed between the data lines needed to be detected and the counter electrode after the voltage signal is charged,

wherein, the scan-line-direction touch position and the data-line-direction touch position indicate a position of the touch point.

2. The method of claim 1, wherein when the scan-line-direction touch position is not detected in the first touch-position sensing step, the first touch-position sensing step is repeated.

3. The method of claim 1, wherein when the data-line-direction touch position is not detected in the second touch-position sensing step, the first touch-position sensing step is repeated.

4. The method of claim 1, wherein the substrate is a TFT substrate.

5. The method of claim 1, wherein when detecting the liquid crystal capacitances formed between the scan lines and the counter electrode, at least one of the scan lines is skipped in the first touch-position sensing step.

6. The method of claim 1, wherein when detecting the liquid crystal capacitances formed between the data lines and the counter electrode, at least one of the data lines is skipped in the second touch-position sensing step.

7. The method of claim 1, further comprising:

a comparing-value setting step, which sets at least one scan-line comparing value and at least one data-line comparing value.

8. The method of claim 7, wherein when a liquid crystal capacitance (C_k) formed between one of the scan lines and the counter electrode is greater than the scan-line comparing value, the first touch-position sensing step determines the location of the scan line corresponding to the liquid crystal capacitance (C_k) is the scan-line-direction touch position.

9. The method of claim 7, wherein when a liquid crystal capacitance (C₁) formed between one of the data lines and the counter electrode is greater than the data-line comparing value, the second touch-position sensing step determines the location of the data line corresponding to the liquid crystal capacitance (C₁) is the data-line-direction touch position.

10. The method of claim 7, wherein the scan-line comparing value is equal to a predetermined value plus a minimum value of the liquid crystal capacitances formed between the scan lines needed to be detected and the counter electrode.

11. The method of claim 7, wherein the data-line comparing value is equal to a predetermined value plus a minimum value of the liquid crystal capacitances formed between the data lines needed to be detected and the counter electrode.

12. The method of claim 7, wherein the scan-line comparing value is equal to a predetermined value plus one of the values of the previously detected liquid crystal capacitances formed between the counter electrode and the scan lines.

13. The method of claim 7, wherein the data-line comparing value is equal to a predetermined value plus one of the values of the previously detected liquid crystal capacitances formed between the counter electrode and the data lines.

14. The method of claim 7, wherein the scan-line comparing value is equal to a predetermined value plus an average of at least two values of the liquid crystal capacitances formed between the scan lines needed to be detected and the counter electrode.

15. The method of claim 7, wherein the data-line comparing value is equal to a predetermined value plus an average of at least two values of the liquid crystal capacitances formed between the data lines needed to be detected and the counter electrode.

16. An LCD (liquid crystal display), which has a counter electrode and a substrate having a plurality of data lines, and a plurality of scan lines and a plurality of pixels, wherein the scan lines are connected to a gate of a TFT in each respective pixel, and the data lines are connected to a source of the TFT in each respective pixel, the LCD comprising:

a first sensing circuit, which respectively electrically connects to the scan lines needed to be detected, detects values of liquid crystal capacitances formed between the scan lines needed to be detected and the counter electrode, and detects a scan-line-direction touch position according to the values of the liquid crystal capacitances formed between the scan lines needed to be detected and the counter electrode, wherein a part of the counter electrode corresponding to a pressure is indented, the distance between the part of the counter electrode and scan line is reduced, and the distance between the part of the counter electrode and data line is reduced;

a timing control circuit, which electrically connects to the first sensing circuit and controls the first sensing circuit to detect the liquid crystal capacitances formed between the scan lines needed to be detected and the counter electrode during idling time in-between writing periods, each of the scan lines turning on sequentially to write image data into the LCD screen in the writing periods;

a voltage-signal generating circuit, which electrically connects to the timing control circuit and each of the data lines, wherein the timing control circuit controls the voltage-signal generating circuit to charge a voltage signal into each of the data lines needed to be detected after the scan-line-direction touch position is detected; and

a second sensing circuit, which respectively electrically connects to each of the data lines needed to be detected, detects values of liquid crystal capacitances formed between the data lines needed to be detected and the counter electrode, and detects a data-line-direction touch position according to the values of the liquid crystal capacitances formed between the data lines needed to be detected and the counter electrode after the voltage signal is charged.

17. The LCD of claim 16, wherein when the first sensing circuit detects the liquid crystal capacitances formed between the scan lines needed to be detected and the counter electrode, at least one of the scan lines is skipped.

18. The LCD of claim 16, wherein when the second sensing circuit detects the liquid crystal capacitances formed between the data lines needed to be detected and the counter electrode, at least one of the data lines is skipped.

19. The LCD of claim 16, wherein the substrate is a TFT substrate.

20. The LCD of claim 16, further comprising:

a comparing-value setting circuit, which respectively electrically connects to the first sensing circuit and the second sensing circuit, and sets at least one scan-line comparing value to be input to the first sensing circuit and at least one data-line comparing value to be input to the second sensing circuit.

21. The LCD of claim 20, wherein when a liquid crystal capacitance (C_k) formed between one of the scan lines and the counter electrode is greater than the scan-line comparing value, the first sensing circuit determines that the location of the scan line corresponding to the liquid crystal capacitance (C_k) is the scan-line-direction touch position.

22. The LCD of claim 20, wherein when a liquid crystal capacitance (C₁) formed between one of the data lines and the counter electrode is greater than the data-line comparing value, the second sensing circuit determines that the location of the data line corresponding to the liquid crystal capacitance (C₁) is the data-line-direction touch position.

23. The LCD of claim 20, wherein the scan-line comparing value is equal to a predetermined value plus a minimum value of the liquid crystal capacitances formed between the scan lines needed to be detected and the counter electrode.

24. The LCD of claim 20, wherein the data-line comparing value is equal to a predetermined value plus a minimum value of the liquid crystal capacitances formed between the data lines needed to be detected and the counter electrode.

25. The LCD of claim 20, wherein the scan-line comparing value is equal to a predetermined value plus one of the values of the previously detected liquid crystal capacitance formed between the counter electrode and the scan lines.

26. The LCD of claim 20, wherein the data-line comparing value is equal to a predetermined value plus one of the values of the previously detected liquid crystal capacitance formed between the counter electrode and the data lines.

27. The LCD of claim 20, wherein the scan-line comparing value is equal to a predetermined value plus an average of at least two values of the liquid crystal capacitances formed between the scan lines needed to be detected and the counter electrode.

28. The LCD of claim 20, wherein the data line comparing value is equal to a predetermined value plus an average of at least two values of the liquid crystal capacitances formed between the data lines needed to be detected and the counter electrode.