Detection method and device for touch point, touch driving circuit, and touch screen

• US 9,372,578 B2
• Filed: 12/13/2013
• Issued: 06/21/2016
• Est. Priority Date: 06/28/2013
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd., Chengdu BOE Optoelectronics Technology Company Limited (BOE Technology Group Co., Ltd.)
• Original Assignee: BOE Technology Group Co., Ltd., Chengdu BOE Optoelectronics Technology Company Limited (BOE Technology Group Co., Ltd.)
• Inventors: Lu, Youqiang, Qiu, Yun, Wang, Jing
• Primary Examiner(s): DINH, DUC Q
• Application Number:
  US14/357,935
• Publication Number:
  US 20150277659A1
• Time in Patent Office: 921 Days
• Field of Search: 345173-181
• US Class Current: 1/1
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/04186 Touch location disambiguation

Abstract

The present invention discloses a touch point detection method, device, a touch driving circuit and a touch panel. After determining a to-be-determined touch point among touch detection points of a touch panel, it is determined whether the to-be-determined touch point is influenced by noise of a display driving circuit according to a touch signal, a first noise value and a second noise value of touch detection points in a line where the to-be-determined touch point is located; and after it is determined that the to-be-determined touch point is influenced by the noise of the display driving circuit, it is determined whether the to-be-determined touch point is a touch point according to the second noise value and a preset first threshold value; the second noise value is the noise value of the touch driving circuit when the display driving circuit is turned on. Because it is determined whether the to-be-determined touch point is influenced by the noise of the display driving circuit before determining whether it is a touch point, it is possible to effectively identify interference of noise on the touch signals, improve signal-to-noise ratio of touch signals, and ensure accuracy of touch determining operation.

Claims

1. A touch point detection method comprising:

determining a to-be-determined touch point among touch detection points of a touch panel;

determining whether the to-be-determined touch point is influenced by noise of a display driving circuit according to a touch signal, a first noise value and a second noise value of touch detection points in a line where the to-be-determined touch point is located;

wherein the first noise value is a noise value of the touch driving circuit when the display driving circuit is not turned on, and the second noise value is a noise value of the touch driving circuit when the display driving circuit is turned on;

upon determining that the to-be-determined touch point is influenced by the noise of the display driving circuit, determining whether the to-be-determined touch point is a touch point according to the second noise value and a first threshold value;

the first threshold value being greater than the first noise value and smaller than the second noise value.

2. The method of claim 1, wherein before determining of a to-be-determined touch point among touch detection points of the touch panel, the method further comprises:

detecting the first noise value of the touch driving circuit when the display driving circuit is not turned on;

after receiving a synchronization signal sent by the display driving circuit, detecting the second noise value of the touch driving circuit when the display driving circuit is turned on; and

determining the first threshold value according to the first noise value and the second noise value.

3. The method of claim 2, further comprising:

determining a second threshold value according to the second noise value, the second threshold value being greater than the second noise value.

4. The method of claim 1, wherein determining of a to-be-determined touch point among touch detection points of the touch panel comprises:

charging and scanning the touch detection points of the touch panel line by line and acquiring touch signals for the touch detection points in sequence;

for each touch detection point, determining a magnitude relation between a touch signal of the touch detection point and the second threshold value;

upon determining that the touch signal of the touch detection point is greater than the second threshold value, determining the touch detection point to be the to-be-determined touch point.

5. The method of claim 4, further comprising:

recording scanning numbers of each line when charging and scanning the touch detection points of the touch panel line by line;

when the scanning numbers reach a preset third threshold value, detecting once again and updating the second noise value;

determining the first threshold value once again according to the first noise value and the updated second noise value.

6. The method of claim 1, wherein determining whether the to-be-determined touch point is influenced by the noise of the display driving circuit comprises:

calculating a weighted average of touch signals of touch detection points other than the to-be-determined touch point and its adjacent touch detection points in the line where the to-be-determined touch point is located;

determining whether an absolute value of difference between the weighted average and the second noise value is not greater than the first noise value;

if so, determining whether the to-be-determined touch point is influenced by the noise of the display driving circuit; and

if not, determining that the to-be-determined touch point is not influenced by the noise of the display driving circuit.

7. The method of claim 1, wherein, upon determining that the to-be-determined touch point is influenced by the noise of the display driving circuit, determining whether the to-be-determined touch point is a touch point comprises:

determining whether an absolute value of difference between the touch signal of the touch detection point and the second noise value is greater than the first threshold value;

if so, determining that the to-be-determined touch point is a touch point and reporting the touch point.

8. The method of claim 1, further comprising:

upon determining that the to-be-determined touch point is not influenced by the noise of the display driving circuit, determining whether the to-be-determined touch point is a touch point according to the first threshold value.

9. The method of claim 8, wherein upon determining that the to-be-determined touch point is not influenced by the noise of the display driving circuit, determining whether the to-be-determined touch point is a touch point comprises:

determining whether the touch signal of the touch detection point is greater than the first threshold value;

if so, determining that the to-be-determined touch point s a touch point and reporting the touch point.

10. A touch point detection device comprising:

a first determining module configured for determining a to-be-determined touch point among touch detection points of a touch panel;

a second determining module configured for determining whether the to-be-determined touch point is influenced by noise of the display driving circuit according to a touch signal, a first noise value and a second noise value of touch detection points in a line where the to-be-determined touch point is located;

wherein the first noise value is a noise value of the touch driving circuit when the display driving circuit is not turned on, and the second noise value is a noise value of the touch driving circuit when the display driving circuit is turned on;

a third determining module configured for, upon determining that the to-be-determined touch point is influenced by the noise of the display driving circuit, determining whether the to-be-determined touch point is a touch point according to the second noise value and a first threshold value;

the first threshold value being greater than the first noise value and smaller than the second noise value.

11. The device of claim 10, further comprising:

a first detection module configured for detecting the first noise value of the touch driving circuit when the display driving circuit is not turned on;

a second detection module configured for, after receiving a synchronization signal sent by the display driving circuit, detecting the second noise value of the touch driving circuit when the display driving circuit is turned on;

a fourth determining module configured for determining the first threshold value according to the first noise value and the second noise value.

12. The device of claim 10, further comprising:

a fifth determining module configured for determining the second threshold value according to the second noise value, the second threshold value being greater than the second noise value.

13. The device of claim 10, wherein the first determining module comprises:

a touch signal detection module configured for charging and scanning the touch detection points in the touch panel line by line and acquiring touch signals for the touch detection points in sequence;

a first judgment module configured for, for each touch detection point, determining a magnitude relationship between a touch signal of the touch detection point and the second threshold value, and upon determining that the touch signal of the touch detection point is greater than the second threshold value, determining the touch detection point to be the to-be-determined touch point.

14. The device of claim 13, wherein the first determining module further comprises:

a recording module configured for recording scanning numbers of each line when charging and scanning the touch detection points of the touch panel line by line;

an updating module configured for detecting once again and updating the second noise value when the scanning numbers reach a preset third threshold value; and

determining the first threshold value once again according to the first noise value and the updated second noise value.

15. The device of claim 10, wherein the second determining module comprises:

a first calculating module configured for calculating a weighted average of touch signals of touch detection points other than the to-be-determined touch point and its adjacent touch detection points in the line where the to-be-determined touch point is located;

a second judgment module configured for determining whether an absolute value of difference between the weighted average and the second noise value is not greater than the first noise value;

if so, determining that the to-be-determined touch point is influenced by the noise of the display driving circuit;

if not, determining that the to-be-determined touch point is not influenced by the noise of the display driving circuit.

16. The device of claim 10, wherein the third determining module is configured to determine whether an absolute value of difference between the touch signal of the touch detection point and the second noise value is greater than the first threshold value;

if so, determine the to-be-determined touch point to be a touch point and report the touch point.

17. The device of claim 10, further comprising:

a sixth determining module configured for, upon determining that the to-be-determined touch point is not influenced by the noise of the display driving circuit, determining whether the to-be-determined touch point is a touch point according to the first threshold value.

18. The device of claim 17, wherein the sixth determining module is configured to determine whether the touch signal for the touch detection point is greater than the first threshold value;

if so, determine the to-be-determined touch point to be a touch point and report the touch point.

19. A touch driving circuit comprising the touch point detection device of claim 10.

20. A touch panel comprising:

a display driving circuit and a touch driving circuit wherein the display driving circuit is configured to send a synchronization signal to the touch driving circuit after displaying a set number of frames of images;

the touch driving circuit is configured to detect a first noise value of the touch driving circuit when the display driving circuit is not turned on;

after receiving the synchronization signal sent by the display driving circuit, detect a second noise value of the touch driving circuit when the display driving circuit is turned on;

determine a to-be-determined touch point among touch detection points of the touch panel;

determine whether the to-be-determined touch point is influenced by noise of the display driving circuit according to a touch signal, a first noise value and a second noise value of the touch detection points in a line where the to-be-determined touch point is located;

upon determining that the to-be-determined touch point is influenced by the noise of the display driving circuit, determine whether the to-be-determined touch point is a touch point according to the second noise value and a first threshold value;

wherein the first threshold value is greater than the first noise value and smaller than the second noise value.