SYSTEM AND METHOD FOR SENSOR DEVICE SIGNALING USING A POLARITY RESET INTERVAL

• US 20120319988A1
• Filed: 06/15/2011
• Published: 12/20/2012
• Est. Priority Date: 06/15/2011
• Status: Abandoned Application

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: SCHWARTZ, Adam
• Application Number:
  US13/161,267
• Publication Number:
  US 20120319988A1
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 2203/04112 Electrode mesh in capacitive digitiser: electrode for touch sensing is formed of a mesh of very fine, normally metallic, interconnected lines that are almost invisible to see. This provides a quite large but transparent electrode surface, without need for ITO or similar transparent conductive material
• 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

A capacitive sensing method includes transmitting a first transmitter signal with a first transmitter electrode such that the first transmitter signal includes a first plurality of sensing cycles. A resulting signal is received with a receiver electrode, wherein the resulting signal comprises effects corresponding to the first transmitter signal. The polarity of each sensing cycle of the first plurality of sensing cycles corresponds to a respective bit within a bit sequence of a first spreading code, and each sensing cycle of the first plurality of sensing cycles comprises a measurement interval and a polarity reset interval.

Claims

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

transmitter module comprising transmitter circuitry, the transmitter module configured to transmit a first transmitter signal with a first transmitter electrode, wherein the first transmitter signal comprises a first plurality of sensing cycles, the polarity of each sensing cycle of the first plurality of sensing cycles corresponds to a respective bit within a bit sequence of a first spreading code, and wherein each sensing cycle of the first plurality of sensing cycles comprises a measurement interval and a polarity reset interval; and

receiver module comprising receiver circuitry, the receiver module configured to receive a resulting signal with a receiver electrode, wherein the resulting signal comprises effects corresponding to the first transmitter signal.

2. The processing system of claim 1, wherein, during the polarity reset interval, a transient response corresponding to a polarity reversal of the resulting signal substantially settles prior to the measurement interval.

3. The processing system of claim 1, wherein the receiver circuitry is configured to receive the resulting signal during the measurement interval.

4. The processing system of claim 1, wherein:

a sensing cycle of the first plurality of sensing cycles has a period;

a polarity reset interval of the sensing cycle lasts for a first duration of the period; and

a measurement interval of the sensing cycle lasts for a second duration of the period, wherein the second duration is longer than the first duration.

5. The processing system of claim 1, wherein the transmitter module is further configured to transmit a second transmitter signal with a second transmitter electrode, wherein the second transmitter signal comprises a second plurality of sensing cycles, the polarity of each sensing cycle of the second plurality of sensing cycles corresponds to a respective bit within a bit sequence of a second spreading code, and each sensing cycle of the second plurality of sensing cycles comprises a measurement interval and a polarity reset interval, and wherein the first transmitter signal and second transmitter signal are simultaneously transmitted.

6. The processing system of claim 5, wherein the first spreading code and the second spreading code are substantially orthogonal.

7. The processing system of claim 5, wherein the first spreading code and the second spreading code are pseudo-random sequences codes.

8. The processing system of claim 1, wherein the processing system further comprises:

calculation module configured to acquire a measurement of a change in capacitive coupling between the first transmitter electrode and the receiver electrode, the measurement based on the resulting signal; and

determination module configured to determine positional information for an input device based on the measurement.

9. The processing system of claim 5, wherein the resulting signal further comprises effects corresponding to the second transmitter signal, and wherein the processing system further comprises:

calculation module configured to acquire a measurement of a change in capacitive coupling between the first transmitter electrode and the receiver electrode and between the second transmitter electrode and the receiver electrode by deconvolving the resulting signal based on the first and second spreading codes; and

determination module configured to determine positional information for an input device based on the measurement.

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

transmitting a first transmitter signal with a first transmitter electrode, the first transmitter signal comprising a first plurality of sensing cycles; and

receiving a resulting signal with a receiver electrode, wherein the resulting signal comprises effects corresponding to the first transmitter signal;

wherein the polarity of each sensing cycle of the first plurality of sensing cycles corresponds to a respective bit within a bit sequence of a first spreading code; and

wherein each sensing cycle of the first plurality of sensing cycles comprises a measurement interval and a polarity reset interval.

11. The method of claim 10, wherein, during the polarity reset interval, a transient response corresponding to a polarity reversal of the resulting signal substantially settles prior to the measurement interval.

12. The method of claim 10, wherein:

a sensing cycle of the first plurality of sensing cycles has a period;

a polarity reset interval of the sensing cycle lasts for a first duration of the period; and

a measurement interval of the sensing cycle for a second duration of the period, wherein the second duration is longer than the first duration.

13. The method of claim 10, further comprising:

transmitting a second transmitter signal with a second transmitter electrode, the second transmitter signal comprising a second plurality of sensing cycles;

wherein the polarity of each sensing cycle of the second plurality of sensing cycles corresponds to a respective bit within a bit sequence of a second spreading code;

wherein each sensing cycle of the second plurality of sensing cycles comprises a measurement interval and a polarity reset interval; and

wherein the first transmitter signal and the second transmitter signal are simultaneously transmitted.

14. The method of claim 13, wherein the first spreading code and the second spreading code are substantially orthogonal.

15. The method of claim 13, wherein the resulting signal further comprises effects corresponding to the second transmitter signal, and wherein the method further comprises:

acquiring a measurement of a change in capacitive coupling between the first transmitter electrode and the receiver electrode and between the second transmitter electrode and the receiver electrode by deconvolving the resulting signal based on the first and second spreading codes; and

determining positional information for an input device based on the measurement.

16. A capacitive sensor device comprising:

a first transmitter electrode;

a receiver electrode; and

a processing system communicatively coupled to the first transmitter electrode and receiver electrode, the processing system configured to;

transmit a first transmitter signal with the first transmitter electrode, wherein the first transmitter signal comprises a first plurality of sensing cycles, the polarity of each of the first plurality of sensing cycles corresponds to a respective bit within a bit sequence of a first spreading code, and each of the first plurality of sensing cycles comprises a measurement interval and a polarity reset interval; and

receive a resulting signal with the receiver electrode, wherein the resulting signal comprises effects corresponding to the first transmitter signal.

17. The capacitive sensor device of claim 16, wherein, during the polarity reset interval, a transient response corresponding to a polarity reversal of the resulting signal substantially settles prior to the measurement interval.

18. The capacitive sensor device of claim 16, wherein:

a sensing cycle of the first plurality of sensing cycles has a period;

a polarity reset interval of the sensing cycle lasts for a first duration of the period; and

a measurement interval of the sensing cycle lasts for a second duration of the period, wherein the second duration is longer than the first duration.

19. The capacitive sensor device of claim 16, further comprising:

a second transmitter electrode;

wherein the processing system is configured to transmit a second transmitter signal with the second transmitter electrode while simultaneously transmitting the first transmitter signal; and

wherein the second transmitter signal comprises a second plurality of sensing cycles, the polarity of each sensing cycle of the second plurality of sensing cycles corresponds to a respective bit within a bit sequence of a second spreading code, and each sensing cycle of the second plurality of sensing cycles comprises a measurement interval and a polarity reset interval.

20. The capacitive sensor device of claim 19, wherein the first spreading code and the second spreading code are substantially orthogonal.