System and method for mathematically independent signaling in gradient sensor devices

• US 9,134,827 B2
• Filed: 12/28/2011
• Issued: 09/15/2015
• Est. Priority Date: 12/28/2011
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Small, Jeffrey A.
• Primary Examiner(s): Johnson, Gerald
• Application Number:
  US13/339,125
• Publication Number:
  US 20130169581A1
• Time in Patent Office: 1,357 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• 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

Abstract

A processing system for an input device includes a transmitter module, a receiver module, and a determination module. The transmitter module is configured to simultaneously drive a first end of a transmitter electrode with a first drive signal and drive a second end of the transmitter electrode with a second drive signal to produce a voltage gradient across the transmitter electrode, wherein the first drive signal and the second drive signal are mathematically independent. The receiver module is configured to receive a resulting signal with a receiver electrode, the resulting signal comprising effects of the voltage gradient. The determination module is configured to determine positional information for an input object based on the resulting signal.

Claims

1. A processing system for an input device, the processing system comprising:

a transmitter module including a first transmitter and a second transmitter,

wherein the first transmitter is configured to drive a first end of a transmitter electrode with a first drive signal comprising a first plurality of voltage transitions and the second transmitter is configured to drive a second end of the transmitter electrode with a second drive signal comprising a second plurality of voltage transitions,

wherein the first drive signal and the second drive signal are configured to be driven simultaneously and to produce a voltage gradient across the transmitter electrode,

wherein the first drive signal and the second drive signal are mathematically independent, and

wherein the first drive signal is different from the second drive signal;

a receiver module, the receiver module configured to receive a resulting signal with a receiver electrode, the resulting signal comprising effects of the voltage gradient; and

a determination module configured to determine positional information for an input object based on the resulting signal.

2. The processing system of claim 1, wherein the first drive signal and the second drive signal are mathematically independent in at least one of frequency and phase.

3. The processing system of claim 1, wherein the first drive signal and the second drive signal are mathematically independent in code.

4. The processing system of claim 1, wherein the first drive signal and second drive signal are substantially orthogonal to one another.

5. The processing system of claim 1, wherein the first drive signal and second drive signal are orthogonal to one another.

6. The processing system of claim 1, wherein the transmitter electrode comprises a substantially uniform resistive material.

7. The processing system of claim 1, wherein the transmitter electrode and the receiver electrode are arranged substantially parallel or substantially perpendicular to one another.

8. A capacitive sensor device comprising:

a transmitter electrode;

a receiver electrode; and

a processing system comprising a first transmitter and a second transmitter, wherein the processing system is communicatively coupled to the transmitter electrode and the receiver electrode, and wherein the processing system is configured to;

simultaneously drive, using the first transmitter, a first end of a transmitter electrode with a first drive signal comprising a first plurality of voltage transitions and drive, using the second transmitter, a second end of the transmitter electrode with a second drive signal comprising a second plurality of voltage transitions to produce a voltage gradient across the transmitter electrode,

wherein the first drive signal and the second drive signal are mathematically independent, and

wherein the first drive signal is different from the second drive signal;

receive a resulting signal with a receiver electrode, the resulting signal comprising effects of the voltage gradient;

demodulate the resulting signal to produce a first demodulated signal based on the first drive signal, and a second demodulated signal based on the second drive signal; and

determine positional information for an input object based on the first and second demodulated signals.

9. The capacitive sensor device of claim 8, wherein the first drive signal and the second drive signal are mathematically independent in at least one of frequency and phase.

10. The capacitive sensor device of claim 8, wherein the first drive signal and the second drive signal are mathematically independent in code.

11. The capacitive sensor device of claim 8, wherein the first drive signal and second drive signal are substantially orthogonal to one another.

12. The capacitive sensor device of claim 8, wherein the first drive signal and second drive signal are orthogonal to one another.

13. The capacitive sensor device of claim 8, wherein the transmitter electrode and the receiver electrode are disposed in a single layer on a common substrate.

14. The capacitive sensor device of claim 8, wherein the transmitter electrode and the receiver electrode are arranged substantially parallel or substantially perpendicular to one another.

15. A method of capacitive sensing, the method comprising:

simultaneously driving, by a first transmitter, a first end of a transmitter electrode with a first drive signal comprising a first plurality of voltage transitions and driving, by a second transmitter, a second end of the transmitter electrode with a second drive signal comprising a second plurality of voltage transitions to produce a voltage gradient across the transmitter electrode, wherein the first drive signal and the second drive signal are mathematically independent, and

wherein the first drive signal is different from the second drive signal;

receiving a resulting signal with a receiver electrode, the resulting signal comprising effects of the voltage gradient;

demodulating the resulting signal to produce a first demodulated signal based on the first drive signal, and a second demodulated signal based on the second drive signal; and

determining positional information for an input object based on the first and second demodulated signals.

16. The method of claim 15, wherein the first drive signal and the second drive signal are mathematically independent in at least one of frequency and phase.

17. The method of claim 15, wherein the first drive signal and the second drive signal are mathematically independent in code.

18. The method of claim 15, wherein the first drive signal and second drive signal are substantially orthogonal to one another.

19. The method of claim 15, wherein the first drive signal and second drive signal are orthogonal to one another.

20. The method of claim 15, wherein the transmitter electrode and the receiver electrode are arranged substantially parallel or substantially perpendicular to one another.