Noise frequency detection method and touch apparatus

• US 8,957,870 B2
• Filed: 10/24/2012
• Issued: 02/17/2015
• Est. Priority Date: 07/06/2012
• Status: Active Grant

• Current Assignee: AU Optronics Corporation
• Original Assignee: AU Optronics Corporation
• Inventors: Lee, Ching-Min
• Primary Examiner(s): Pham, Long D
• Application Number:
  US13/658,896
• Publication Number:
  US 20140009408A1
• Time in Patent Office: 846 Days
• Field of Search: 345/173
• US Class Current: 345/173
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

A noise frequency detection method includes steps of: providing a frequency of system clock; fixing an operation frequency band of a sensing signal; adjusting a pulse width of the sensing signal and sampling a noise, wherein each pulse width of the sensing signal corresponds to a noise value of the noise; and referring the pulse width corresponding to a preset value of the noise to as a critical value, and obtaining a noise frequency from dividing the frequency of system clock by the critical value. A touch apparatus is also provided.

Claims

1. A noise frequency detection method, comprising:

providing a frequency of system clock;

fixing an operation frequency band of a sensing signal;

adjusting a pulse width of the sensing signal and sampling a noise, wherein each pulse width of the sensing signal corresponds to a noise value of the noise; and

referring the pulse width corresponding to a preset value of the noise to as a critical value, and obtaining a noise frequency from dividing the frequency of system clock by the critical value.

2. The noise frequency detection method according to claim 1, wherein the pulse width of the sensing signal is adjusted from large to small while the noise is being sampled.

3. The noise frequency detection method according to claim 1, wherein the pulse width of the sensing signal is adjusted from small to large while the noise is being sampled.

4. The noise frequency detection method according to claim 1, further comprising executing a noise filtering operation once the noise frequency is obtained.

5. The noise frequency detection method according to claim 4, wherein the noise filtering operation is for filtering out the noise frequency.

6. The noise frequency detection method according to claim 1, wherein the sensing signal has a minimum interference from the noise if the pulse width of the sensing signal is equal to or multiple of a cycle of the noise.

7. The noise frequency detection method according to claim 1, wherein the preset value is a minimum noise value of the noise.

8. The noise frequency detection method according to claim 1, wherein the preset value is a maximum noise value of the noise.

9. The noise frequency detection method according to claim 1, wherein the operation frequency band of the sensing signal is smaller than the frequency of system clock.

10. The noise frequency detection method according to claim 1, wherein the unit of the pulse width is number of system clock.

11. A touch apparatus, comprising:

a touch panel comprising a plurality of driving lines and at least one sensing line; and

a control circuit electrically connected to the touch panel and comprising;

a driving unit electrically connected to the driving lines;

a sensing unit electrically connected to the at least one sensing line; and

a processing unit, electrically connected to the driving unit and the sensing unit, configured to obtain a sensing signal through the sensing unit and adjust the obtained sensing signal to have a pulse width equal to or multiple of a cycle of a noise;

wherein the processing unit is further configured to execute a noise frequency detection operation, the noise frequency detection operation comprises;

providing a frequency of system clock;

fixing an operation frequency band of the sensing signal;

adjusting the pulse width of the sensing signal and sampling the noise, wherein each pulse width of the sensing signal corresponds to a noise value of the noise; and

referring the pulse width corresponding to a minimum noise value to as a critical value, and obtaining a frequency of the noise from dividing the frequency of system clock by the critical value.

12. The touch apparatus according to claim 11, wherein the pulse width of the sensing signal is adjusted from large to small while the noise is being sampled.

13. The touch apparatus according to claim 11, wherein the pulse width of the sensing signal is adjusted from small to large while the noise is being sampled.

14. The touch apparatus according to claim 11, wherein the sensing signal has a minimum interference from the noise if the pulse width of the sensing signal is equal to or multiple of a cycle of the noise.

15. The touch apparatus according to claim 11, wherein the touch apparatus is a capacitive touch apparatus.

16. The touch apparatus according to claim 11, further comprising:

a filtering unit configured to filter out the noise.

17. The touch apparatus according to claim 11, wherein the operation frequency band of the sensing signal is smaller than the frequency of system clock.

18. The touch apparatus according to claim 11, wherein the unit of the pulse width is number of system clock.