Noise suppression method and system for touch detection and touch terminal

Patent metadata

Field	Value
Publication number	US-9864465-B2
Application number	US-201414548954-A
Country	US
Kind code	B2
Filing date	Nov 20, 2014
Priority date	Jul 19, 2012
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

The present invention is applicable to the technical field of touch control. Provided are a touch detection system and a noise suppression method therefor. The method includes the steps of: sequentially driving a touch detection system with all driving frequencies that the touch detection system supports, and detecting a currently existing interference strength value when driving with each driving frequency; and frequency-hopping to the driving frequency corresponding to the minimum interference strength value, and driving the touch detection system with the driving frequency corresponding to the minimum interference strength value to perform a normal operation. By detecting an interference strength value at each driving frequency and then using the driving frequency corresponding to the minimum interference strength value as an operating frequency of a touch terminal, the present invention minimizes the signal interference of a touch detection system.

First claim

What is claimed is:

1. A noise suppression method for touch detection, comprising the following steps:
before a normal scan, detecting an interference strength value at the current operating frequency point; when the interference strength value is less than a first threshold value, driving a touching detection system with a driving frequency corresponding to the interference strength value at the current operating frequency point, else performing following steps:
sequentially driving a touch detection system with a plurality of driving frequencies supported by the touch detection system, and detecting an interference strength value of the touch detection system when driving with each driving frequency; and frequency-hopping to a driving frequency corresponding to the minimum interference strength value, and driving the touch detection system to perform a normal operation with the driving frequency corresponding to the minimum interference strength value,
wherein, the step of sequentially driving a touch detection system with a plurality of driving frequencies supported by the touch detection system, and detecting an interference strength value of the touch detection system when driving with each driving frequency includes the following steps:
driving the touch detection system with one driving frequency supported by the touch detection system, and obtaining an interference strength value at the current driving frequency;
judging whether the obtained interference strength value at the current driving frequency is greater than a predetermined first threshold value;
when the obtained interference strength value at the current driving frequency is greater than a predetermined first threshold value, further switching to another driving frequency supported by the touch detection system to drive the touch detection system, detecting and judging whether the current interference strength value is greater than the predetermined first threshold value, until interference strength values at a plurality of supported driving frequencies are obtained;
when consecutively detecting that interference strength values at a plurality of frequencies are all less than a predetermined second threshold value, quitting the current noise detection.

2. The noise suppression method for touch detection according to claim 1 , wherein, the step of driving the touch detection system with one driving frequency supported by the touch detection system, and obtaining an interference strength value at the current driving frequency includes the following steps:
at the current driving frequency, consecutively scanning the same driving electrode twice to obtain two groups of sampling data, calculating the difference value between the two groups of sampling data, and using the obtained difference value as an interference component of the current driving electrode; obtaining interference components of a plurality of driving electrodes at the current driving frequency according to this method, calculating a sum of absolute values of the interference components, and using the sum as the interference strength value of the touch detection system at the current driving frequency.

3. The noise suppression method for touch detection according to claim 2 , wherein, the step of driving the touch detection system with one driving frequency supported by the touch detection system, and obtaining an interference strength value at the current driving frequency further includes the following steps:
calculating a plurality of interference strength values at the current driving frequency; and
selecting the greatest value from the plurality of obtained interference strength values and using the greatest value as the interference strength value at the current driving frequency.

4. The noise suppression method for touch detection according to claim 3 , wherein, between the step of calculating a plurality of interference strength values at the current driving frequency and the step of selecting the greatest value from the plurality of obtained interference strength values and using the greatest value as the interference strength value at the current driving frequency, the method further includes the following step:
judging whether the plurality of obtained interference strength values are all less than a predetermined third threshold value; when the plurality of obtained interference strength values are all less than a predetermined third threshold value, calculating the plurality of interference strength values at the current driving frequency again; else selecting the greatest value from the plurality of obtained interference strength values and using the greatest value as the interference strength value at the current driving frequency.

5. The noise suppression method for touch detection according to claim 1 , wherein, after the step of frequency-hopping to a driving frequency corresponding to the minimum interference strength value, and driving the touch detection system to perform a normal operation with the driving frequency corresponding to the minimum interference strength value, the method further includes the following step:
judging whether the minimum interference strength value is greater than a predetermined fourth threshold value; when the minimum interference strength value is greater than a predetermined fourth threshold value, using the minimum interference strength value as the predetermined first threshold value; else using a sum of the minimum interference strength value and a predetermined interference constant value as the predetermined first threshold value.

6. The noise suppression method for touch detection according to claim 1 , wherein, the step of when the obtained interference strength value at the current driving frequency is greater than a predetermined first threshold value, further switching to another driving frequency supported by the touch detection system to drive the touch detection system, detecting and judging whether the current interference strength value is greater than the predetermined first threshold value, until interference strength values at a plurality of supported driving frequencies are obtained; when consecutively detecting that interference strength values at a plurality of frequencies are all less than a predetermined second threshold value, quitting the current noise detection includes the following steps:
when interference strength values corresponding to a group of consecutively switched driving frequencies are all less than the predetermined second threshold value, and this group of driving frequencies is the first scanned group, or the interference strength values corresponding to the group of consecutively switched driving frequencies are all not less than the predetermined second threshold value, but all frequencies have been switched, selecting a driving frequency corresponding to the minimum interference strength value from the switched driving frequencies, using the selected driving frequency as a target frequency of frequency-hopping, and using the minimum interference strength value as the predetermined first threshold value.

7. The noise suppression method for touch detection according to claim 6 , wherein, the method further includes the following steps:
when the interference strength values corresponding to the group of consecutively switched driving frequencies are all less than the predetermined second threshold value, and this group of driving frequencies is not the first scanned group, further judging whether the latest two groups of scanned frequencies are the first two groups of scanned frequencies;
when the judging result is yes, abandoning the interference strength values corresponding to this group of frequencies; and when the judging result is no, abandoning the

Assignees

• Shenzhen Goodix Tech Co Ltd

Inventors

• Ye Jinchun
• Wang Haolei
• Ruan Bin

Classifications

• G06F3/0418 Primary

  for error correction or compensation, e.g. based on parallax, calibration or alignment · CPC title

• G06F3/04184 Primary

  Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally · CPC title