Touch recognition method and system for a capacitive touch apparatus

• US 9,367,190 B2
• Filed: 09/15/2014
• Issued: 06/14/2016
• Est. Priority Date: 09/13/2013
• Status: Active Grant

• Current Assignee: Apex Material Technology Corp., Imagination Broadway Ltd.
• Original Assignee: Apex Material Technology Corp., Imagination Broadway Ltd.
• Inventors: Ding, Ke-hao, Liao, Zong-Bin, Qiu, Zhong-peng, Lee, Shang-Li
• Primary Examiner(s): Snyder, Adam J
• Application Number:
  US14/486,049
• Publication Number:
  US 20150077389A1
• Time in Patent Office: 638 Days
• Field of Search: 345/174, 178/18.06
• US Class Current: 1/1
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• 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

The present invention discloses a method and system for touch signal recognition adapted to be used in a capacitive touch panel or apparatus. In order to achieve an objection of enhancement of a touch signal for recognition and getting rid of noise impact simultaneously, the present invention discloses a touch recognition method that actually includes two different measurement cycles to acquire two different sample voltage values. Consequently, noise impact can be removed by calculation of a sample voltage value difference between two different sample voltage values, at the same time, and the sample voltage value difference can provide a double magnitude as disclosed in the prior art to enhance accuracy for recognizing a user touch input while preventing from influence of noise.

Claims

1. A method for a capacitive touch panel having a plurality of driving electrodes and a plurality of sensing electrodes, said method comprising:

a plurality of first measurement cycles, acquiring a plurality of first sample voltage values, each of the first measurement cycle comprising;

(1) charging the driving electrode to a High electric potential by supplying a driving current to the driving electrode, wherein the sensing electrode is configured in a floating potential;

(2) measuring the sensing voltage on the sensing electrode with a charge sensing circuit, wherein the sensing electrode is configured in a floating potential and coupled to the charge sensing circuit;

a plurality of second measurement cycles, acquiring a plurality of second sample voltage values, each of the second measurement cycle comprising;

(1) charging the sensing electrode for a predetermined time interval by supplying a charging current while the driving electrode is driven continuously at the High electric potential, wherein the sensing electrode is configured in the floating potential and switched to be coupled to an charging circuit;

(2) terminating charging the sensing electrode, wherein the sensing electrode is configured continuously in the floating potential;

(3) measuring the sensing voltage on the sensing electrode with the charge sensing circuit, wherein the sensing electrode is configured in a floating potential and coupled to the charge sensing circuit while the driving electrode is switched to be configured in a ground potential; and

generating a sensing signal with calculating and processing of a plurality of difference sample voltage values between the first sample voltage values and the second sample voltage values, wherein the sensing signal is defined as a baseline signal if there is no any finger or other object in close proximity to the surface of the capacitive touch panel.

2. The method according to claim 1, wherein the driving electrodes and the sensing electrodes are initially configured in a ground potential, and the sensing electrodes are reset to be configured in a ground potential upon completion of acquiring the first plurality of voltage values.

3. The method according to claim 1, wherein the first measurement cycles are performed after the second measurement cycles in order.

4. The method according to claim 1, wherein the sensing signal is defined as a contact signal if there is a finger or other object in close proximity to the surface of the capacitive touch panel.

5. The method according to claim 4, wherein a signal difference between the contact signal and the baseline signal is defined as a touch signal, and the touch signal is recognized to be a valid signal and outputted when the voltage magnitude of the touch signal is above or equal to a default threshold value.

6. The method according to claim 4, wherein a signal difference between the contact signal and the baseline signal is defined as a touch signal, and the touch signal is recognized to be an invalid signal and discarded when the voltage magnitude of the touch signal is below a default threshold value.

7. A capacitive sensor device, comprising:

a plurality of driving electrodes and a plurality of sensing electrodes, and

a processing system respectively coupled to the driving electrodes and the sensing electrodes, said processing system for touch signal recognition is configured to;

perform a plurality of first measurement cycles to acquire a plurality of first sample voltage values, each of the first measurement cycle comprising;

(1) charging the driving electrode to a High electric potential by supplying a driving current to the driving electrode, wherein the sensing electrode is configured in a floating potential;

(2) measuring the sensing voltage on the sensing electrode with a charge sensing circuit, wherein the sensing electrode is configured in a floating potential and coupled to an charge sensing circuit;

perform a plurality of second measurement cycles to acquire a plurality of second sample voltage values, each of the second measurement cycle comprising;

(1) charging the sensing electrode for a predetermined time interval by supplying a charging current while the driving electrode is driven continuously at the High electric potential, wherein the sensing electrode is configured in the floating potential and switched to be coupled to an charging circuit;

(2) terminating charging the sensing electrode, wherein the sensing electrode is configured continuously in the floating potential;

(3) measuring the sensing voltage on the sensing electrode with the charge sensing circuit, wherein the sensing electrode is configured in a floating potential and coupled to the charge sensing circuit while the driving electrode is switched to be configured in a ground potential; and

generate a sensing signal by calculating and processing a plurality of difference sample voltage values between the first sample voltage values and the second sample voltage values, wherein the sensing signal is defined as a baseline signal if there is no finger or other object in close proximity to the surface of the capacitive touch panel.

8. The device according to claim 7, wherein the driving electrodes and the sensing electrodes are initially configured in a ground potential, and the sensing electrodes are reset to be configured in a ground potential upon completion of acquiring the first plurality of voltage values.

9. The device according to claim 7, wherein the first measurement cycles are performed after the second measurement cycles in order.

10. The device according to claim 7, wherein the sensing signal is defined as a contact signal if there is a finger or other object in close proximity to the surface of the capacitive touch panel.

11. The device according to claim 10, wherein a signal difference between the contact signal and the baseline signal is defined as a touch signal, and the touch signal is recognized to be a valid signal and outputted when the voltage magnitude of the touch signal is above or equal to a default threshold value.

12. The device according to claim 10, wherein a signal difference between the contact signal and the baseline signal is defined as a touch signal, and the touch signal is recognized to be an invalid signal and discarded when the voltage magnitude of the touch signal is below a default threshold value.

13. A capacitive touch apparatus, comprising:

a capacitive touch screen unit which comprises a plurality of driving electrodes and a plurality of sensing electrodes to form a plurality of capacitive sensors for sensing a touch;

a driving circuit operable to drive the driving electrodes for inducing charge onto the capacitive sensors;

a charge sensing circuit operable to perform a charge measurement;

a charging circuit operable to supply a charging current to the sensing electrodes; and

a control unit coupled to the driving circuit, the charge sensing circuit, and the charging circuit, wherein the control unit is operable to perform operations for touch signal recognition comprising;

controlling to perform a plurality of first measurement cycles to acquire a plurality of first sample voltage values, wherein the driving electrodes are controlled to be charged to a High electric potential and the sensing electrodes are controlled to be configured in a floating potential and coupled to the charge sensing circuits and then the capacitive sensors are sequentially measured with the charge sensing circuits to acquire the first sample voltage values;

controlling to perform a plurality of second measurement cycles to acquire a plurality of second sample voltage values, wherein the sensing electrode are controlled to be charged for a predetermined time interval and terminated to be charged with the charging circuit and then the capacitive sensors are sequentially measured with the charge sensing circuits to acquire the second sample voltage values, and wherein the sensing electrodes are controlled to be configured in the floating potential while the driving electrodes are charged continuously at the High electric potential; and

wherein the sensing electrodes are configured continuously in the floating potential as well as coupled to the charge sensing circuit while the driving electrodes are switched to be configured in a ground potential; and

processing to generate a sensing signal by calculating a plurality of difference sample values between the first sample voltage values and the second sample voltage values, wherein the sensing signal is defined as a baseline signal if there is no finger or other object in close proximity to the surface of the capacitive touch panel.

14. The apparatus according to claim 13, wherein the sensing electrodes are coupled to the charging circuit during charging period.

15. The apparatus according to claim 13, wherein the sensing electrodes are coupled to the charge sensing circuit for measurement to acquire the second sample voltage values.

16. The apparatus according to claim 13, wherein the driving electrodes and the sensing electrodes are initially configured in a ground potential, and the sensing electrodes are reset to be configured in a ground potential upon completion of acquiring the first plurality of voltage values.

17. The apparatus according to claim 13, wherein the first measurement cycles are performed after the second measurement cycles in order.

18. The apparatus according to claim 13, wherein the sensing signal is defined as a contact signal if there is a finger or other object in close proximity to the surface of the capacitive touch panel.

19. The apparatus according to claim 18, wherein a signal difference between the contact signal and the baseline signal is defined as a touch signal, and the touch signal is recognized to be a valid signal and outputted when the voltage magnitude of the touch signal is above or equal to a default threshold value.

20. The apparatus according to claim 18, wherein a signal difference between the contact signal and the baseline signal is defined as a touch signal, and the touch signal is recognized to be an invalid signal and discarded when the voltage magnitude of the touch signal is below a default threshold value.