Capacitive touch device, capacitive communication device and communication system

• US 9,389,742 B2
• Filed: 12/10/2014
• Issued: 07/12/2016
• Est. Priority Date: 12/10/2014
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: PixArt Imaging Incorporated
• Inventors: Touney, David, Crandall, Ken, Lo, Chung-Wen, Murphy, Tom, Chen, Hsin-Chia
• Primary Examiner(s): Cheng, Joe H
• Application Number:
  US14/565,622
• Publication Number:
  US 20160170516A1
• Time in Patent Office: 580 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 3/04162 for exchanging data with external devices, e.g. smart pens, via the digitiser sensing hardware
• CPC Class Codes: G06F 3/04164 Connections between sensors and controllers, e.g. routing lines between electrodes and connection pads
• 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

There is provided a capacitive touch device including a touch panel, a detection circuit and a processing unit. The touch panel includes a plurality of drive electrodes and a plurality of receiving electrodes configured to form a coupling electric field with an external touch panel, and the receiving electrodes are respectively configured to output a detection signal. The detection circuit is coupled to one of the receiving electrodes and configured to modulate the detection signal with two signals to generate two detection components. The processing unit is configured to obtain a phase value according to the two detection components to accordingly decode transmission data.

Claims

1. A capacitive touch device, configured to perform a near field communication with an external touch panel, the capacitive touch device comprising:

a touch panel comprising a plurality of drive electrodes and a plurality of receiving electrodes configured to form a coupling electric field with the external touch panel, wherein the receiving electrodes are respectively configured to output a detection signal according to the coupling electric field;

a detection circuit, coupled to one of the receiving electrodes, configured to modulate the detection signal respectively with two signals to generate two detection components; and

a processing unit configured to obtain a norm of vector according to the two detection components to accordingly identify a touch event and obtain a phase value according to the two detection components to accordingly decode transmission data.

2. The capacitive touch device a s claimed in claim 1, further comprising a plurality of drive circuits respectively configured to output a drive signal to the drive electrodes, wherein the drive signal is a phase-fixed drive signal or a phase-modulated drive signal.

3. The capacitive touch device as claimed in claim 1, wherein the two signals are orthogonal to each other.

4. The capacitive touch device as claimed in claim 1, wherein the processing unit is configured to calculate the norm of vector and the phase value according to an identical pair of the two detection components.

5. The capacitive touch device as claimed in claim 1, wherein the processing unit is configured to alternatively calculate the norm of vector and the phase value according to different pairs of the two detection components.

6. The capacitive touch device as claimed in claim 1, wherein the processing unit is configured to decode the transmission data but stop identifying the touch event when identifying that a correlation between a plurality of transmission data and a predetermined code sequence exceeds a threshold.

7. The capacitive touch device as claimed in claim 6, wherein the predetermined code sequence includes Barker codes.

8. The capacitive touch device as claimed in claim 1, wherein the processing unit is configured to decode the transmission data but stop identifying the touch event when identifying that a plurality of transmission data match a predetermined code sequence.

9. A communication system comprising:

a first touch panel; and

a second touch panel comprising;

a plurality of drive electrodes and a plurality of receiving electrodes configured to form a coupling electric field with the first touch panel, wherein the receiving electrodes are respectively configured to output a second detection signal according to the coupling electric field;

a second drive circuit, coupled to one of the drive electrodes, configured to output a phase-fixed drive signal or a phase-modulated drive signal to the drive electrode coupled thereto;

a second detection circuit, coupled the receiving electrode associated with the drive electrode coupled to the second drive circuit, configured to modulate the second detection signal respectively with two signals to generate two detection components; and

a second processing unit configured to obtain a norm of vector according to the two detection components to accordingly identify a touch event.

10. The communication system as claimed in claim 9, wherein the phase-modulated drive signal is a phase shift keying signal or a differential phase shift keying signal, and the two signals have different phases.

11. The communication system as claimed in claim 9, wherein the phase-fixed drive signal is outputted when the second drive circuit does not receive a communication enabling signal, whereas the phase-modulated signal is outputted when the second drive circuit receives the communication enabling signal.

12. The communication system as claimed in claim 11, wherein the second processing unit is configured to output the communication enabling signal to the second drive circuit when receiving a trigger signal of a predetermined application or a press signal of a button.

13. The communication system as claimed in claim 11, wherein the second processing unit is further configured to decode a phase value according to the two detection components, and output the communication enabling signal to the second drive circuit when identifying that a plurality of phase values match a predetermined code sequence.

14. The communication system as claimed in claim 11, wherein the second processing unit is further configured to decode a phase value according to the two detection components, and output the communication enabling signal to the second drive circuit when identifying that a correlation between a plurality of phase values and a predetermined code sequence exceeds a threshold.

15. The communication system as claimed in claim 14, wherein the predetermined code sequence includes Barker codes.

16. The communication system as claimed in claim 14, wherein the first touch panel comprises:

at least one drive electrode configured to form the coupling electric field with the receiving electrodes of the second touch panel; and

a first drive circuit configured to output a phase-modulated drive signal of the predetermined code sequence to the at least one drive electrode of the first touch panel.

17. A capacitive communication device, configured to perform a near field communication with an external electric field, the capacitive communication device comprising:

at least one receiving electrode, configured as a receiving antenna and configured to form a coupling electric field with the external electric field, wherein the receiving electrode is configured to output a detection signal according to the coupling electric field;

a detection circuit, coupled to the at least one receiving electrode, configured to modulate the detection signal respectively with two signals to generate two detection components; and

a processing unit configured to obtain a phase value according to the two detection components to accordingly decode transmission data.

18. The capacitive communication device as claimed in claim 17, wherein the processing unit is further configured to perform a synchronization process in which the processing unit is configured to compare a plurality of transmission data with a predetermined code sequence.

19. The capacitive communication device as claimed in claim 18, wherein the predetermined code sequence includes Barker codes.

20. The capacitive communication device as claimed in claim 17, wherein the processing unit is configured to obtain the phase value by calculating an arctangent function of the two detection components, and the two signals have different phases.