NOISE SUPPRESSION METHOD AND SYSTEM FOR TOUCH DETECTION AND TOUCH TERMINAL

• US 20150077402A1
• Filed: 11/20/2014
• Published: 03/19/2015
• Est. Priority Date: 07/19/2012
• Status: Active Grant

• Current Assignee: Shenzhen Goodix Technology Co., Ltd.
• Original Assignee: Shenzhen Huiding Technology Co., Ltd.
• Inventors: Ye, Jinchun, Wang, Haolei, Ruan, Bin
• Granted Patent: US 9,864,465 B2
• Time in Patent Office: Days
• US Class Current: 345/178
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally

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.

Claims

1. A noise suppression method for touch detection, comprising the following steps:

sequentially driving a touch detection system with all 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.

2. The noise suppression method for touch detection according to claim 1, wherein, the step of sequentially driving a touch detection system with all 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;

if yes, 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 all supported driving frequencies are obtained;

if 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, and backing the detected frequency point.

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 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.

4. The noise suppression method for touch detection according to claim 3, 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.

5. The noise suppression method for touch detection according to claim 4, 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;

if yes, calculating the plurality of interference strength values at the current driving frequency again;

if no, 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.

6. The noise suppression method for touch detection according to claim 2, 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;

if yes, using the minimum interference strength value as the predetermined first threshold value;

if no, using a sum of the minimum interference strength value and a predetermined interference constant value as the predetermined first threshold value.

7. The noise suppression method for touch detection according to claim 2, wherein, the step of if yes, 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 all supported driving frequencies are obtained;

if 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, and backing the detected frequency point includes the following steps;

if 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.

8. The noise suppression method for touch detection according to claim 7, wherein, the method further includes the following steps:

if 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;

if the judging result is yes, abandoning the interference strength values corresponding to this group of frequencies; and

if the result is no, abandoning the interference strength values corresponding to the latest two groups of scanned frequencies.

9. A noise suppression system for touch detection, comprising:

a driving unit configured to drive a touch detection system with a certain frequency;

a drive control unit configured to control the driving unit to sequentially drive the touch detection system with all driving frequencies supported by the touch detection system;

an interference detecting unit configured to detect an interference strength value of the touch detection system when the driving unit drives with each driving frequency; and

a frequency-hopping unit configured to frequency-hops to a driving frequency corresponding to the minimum interference strength value according to the detection result of the interference detecting unit, and thereby make the driving unit drive the touch detection system to perform a normal operation with the driving frequency corresponding to the minimum interference strength value.

10. The noise suppression system for touch detection according to claim 9, wherein, the interference detecting unit includes:

an interference strength detecting module configure to;

when the driving unit drives the touch detection system with a driving frequency supported by the touch detection system, obtain an interference strength value at the current driving frequency;

a first judging module configured to determine the interference strength value obtained by the interference strength detecting module and judge whether it is greater than a predetermined first threshold value; and

a driving frequency switching module configured to;

when the judging result of the first judging module is greater, further switch to another driving frequency supported by the touch detection system to drive the touch detection system, and trigger the drive control unit to control the driving unit to drive the touch detection system with the switched driving frequency;

wherein, the first judging module and the driving frequency switching module repeat the judging and switching processes many times until interference strength values at all supported frequencies are obtained;

during this process, if the first judging module consecutively detects that interference strength values at a plurality of frequencies are all less than a predetermined second threshold value, the current noise detection is quitted, and the detected frequency point is backed.

11. The noise suppression system for touch detection according to claim 10, wherein, the interference strength detecting module further includes:

an interference component calculating sub-module configured to;

at the current driving frequency, consecutively scan each driving electrode twice to obtain two groups of sampling data, calculate the difference value between the two groups of sampling data, and use the obtained difference value as an interference component of the corresponding driving electrode; and

a first interference strength calculating sub-module configured to;

calculate a sum of absolute values of the interference components obtained by the interference component calculating sub-module, and use the sum as the interference strength value of the touch detection system at the current driving frequency.

12. The noise suppression system for touch detection according to claim 11, wherein, the interference strength detecting module further includes:

a cycle control sub-module configured to control the interference component calculating sub-module and the first interference strength calculating sub-module to operate repeatedly and obtain a plurality of interference strength values at the current driving frequency; and

a second interference strength calculating sub-module configured to select the greatest value from the plurality of interference strength values obtained by the cycle control sub-module and use the greatest value as the interference strength value at the current driving frequency

13. The noise suppression system for touch detection according to claim 12, wherein, the interference strength detecting module further includes:

a second judging sub-module configured to;

judge whether the plurality of interference strength values obtained by the cycle control sub-module are all less than a predetermined third threshold value;

if yes, control the cycle control sub-module to perform a cycle control again; and

if no, control the second interference strength calculating sub-module to select the greatest value from the plurality of interference strength values and use the greatest value as the interference strength value at the current driving frequency.

14. The noise suppression system for touch detection according to claim 10, wherein, the noise suppression system for touch detection further includes:

a third judging module configured to;

judge whether the minimum interference strength value is greater than a predetermined fourth threshold value;

if yes, use the minimum interference strength value as the predetermined first threshold value; and

if no, use a sum of the minimum interference strength value and a predetermined interference constant value as the predetermined first threshold value.

15. The noise suppression system for touch detection according to claim 10, wherein, the interference detecting unit further includes:

a fourth judging module configured to judge whether interference strength values corresponding to a group of driving frequencies consecutively switched by the driving frequency switching module are all less than the predetermined second threshold value, and this group of driving frequencies is the first scanned group, or whether 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;

wherein, when the judging result of the fourth judging module is yes, the frequency-hopping unit selects one frequency corresponding to the minimum interference strength value from the switched frequencies, uses the selected frequency as a target frequency of frequency-hopping, and uses the minimum interference strength value as the first threshold value.

16. The noise suppression system for touch detection according to claim 15, wherein, the interference detecting unit further includes:

a fifth judging module configured to;

judge whether the interference strength values corresponding to the group of driving frequencies consecutively switched by the driving frequency switching module are all less than the predetermined second threshold value, and this group of driving frequencies is not the first scanned group; and

if yes, further judge whether the latest two groups of scanned frequencies are the first two groups of scanned frequencies;

wherein, if the judging result of the fifth judging module is yes, the frequency-hopping unit abandons the interference strength values corresponding to this group of frequencies; and

if the judging result is no, the frequency-hopping unit abandons the interference strength values corresponding to the latest two groups of scanned frequencies.

17. A touch terminal comprising a touch detection device;

wherein, the touch detection device includes a noise suppression system for touch detection of claim 9.