METHODS AND SYSTEMS FOR DETECTING A POSITION-BASED ATTRIBUTE OF AN OBJECT USING DIGITAL CODES

• US 20150185920A1
• Filed: 12/23/2014
• Published: 07/02/2015
• Est. Priority Date: 11/15/2005
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Reynolds, J. Kurth
• Granted Patent: US 9,348,477 B2
• Time in Patent Office: 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 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• CPC Class Codes: G06F 3/04186 Touch location disambiguation
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: H03K 17/962 Capacitive touch switches

Abstract

Methods, systems and devices are described for detecting a position-based attribute of a finger, stylus or other object with a touchpad or other sensor having a touch-sensitive region that includes a plurality of electrodes. Modulation signals for one or more electrodes are produced as a function of any number of distinct digital codes. The modulation signals are applied to an associated at least one of the plurality of electrodes to obtain a resultant signal that is electrically affected by the position of the object. The resultant signal is demodulated using the plurality of distinct digital codes to discriminate electrical effects produced by the object. The position-based attribute of the object is then determined with respect to the plurality of electrodes from the electrical effects.

Claims

1. A method of capacitive sensing with a position sensor, the method comprising:

simultaneously transmitting a first modulation signal with a first transmitter electrode and a second modulation signal with a second transmitter electrode, wherein the first and second modulation signals are distinct modulation signals based different ones of a plurality of distinct digital codes, and further wherein at least one of the plurality of distinct digital codes indicates driven and un-driven states;

receiving resultant signals with a plurality of receiver electrodes, wherein the resultant signals comprise electrical effects associated with the first and second modulation signals; and

determining a first position-based attribute of a first object and second position-based attribute of a second object based on the resultant signals.

2. The method of claim 1 wherein each of the plurality of distinct digital codes comprises one of a binary, ternary, and multi-level code.

3. The method of claim 1 wherein simultaneously transmitting the first modulation signal with the first transmitter electrode and the second modulation signal with the second transmitter electrode comprises one of:

frequency modulating a carrier signal according to the distinct digital codes;

amplitude modulating a carrier signal according to the distinct digital codes; and

phase modulating a carrier signal according to the distinct digital codes.

4. The method of claim 1 wherein determining the first position-based attribute and the second position-based attribute comprises determining positional information for the first and second objects with respect to a sensing region of the position sensor.

5. The method of claim 1, wherein the distinct digital codes are mathematically independent.

6. The method of claim 1, wherein each of the plurality of distinct digital codes comprises a code selected from the group consisting of Walsh-Hadamard codes, Gold codes, Kasami Codes, Barker Codes and Psuedo-Random Digital Codes.

7. The method of claim 1, wherein the first position-based attribute comprises one of a speed, velocity, acceleration and a change in position of the first input object.

8. A controller for a capacitive position sensor, the controller comprising:

drive circuitry configured to simultaneously transmit a first modulation signal with a first transmitter electrode and a second modulation signal with a second transmitter electrode, wherein the first and second modulation signals are distinct signals based on distinct digital codes, respectively, and further wherein at least one of the distinct digital codes indicates driven and un-driven states; and

receiver circuitry configured to receive resultant signals with a plurality of receiver electrodes, the resultant signals comprising electrical effects associated with the first and second modulation signals;

wherein the controller is configured determine a first position-based attribute of a first object and a second position-based attribute of a second object based on the resultant signals.

9. The controller of claim 8, wherein the distinct digital codes comprise one of a binary, ternary, and multi-level code.

10. The controller of claim 8, wherein the drive circuitry is configured to simultaneously transmit the first modulation signal with the first transmitter electrode and the second modulation signal with the second transmitter electrode by one of:

frequency modulating a carrier signal according to the distinct digital codes;

amplitude modulating a carrier signal according to the distinct digital codes; and

phase modulating a carrier signal according to the distinct digital codes.

11. The controller of claim 8, wherein the distinct digital codes are mathematically independent.

12. The controller of claim 8, wherein each of the distinct digital codes comprises a code selected from the group consisting of Walsh-Hadamard codes, Gold codes, Kasami Codes, and Barker Codes.

13. The controller of claim 8, wherein the distinct digital codes comprise Pseudo-Random codes.

14. The controller of claim 8, further configured to generate the distinct digital codes by shifting a digital bit sequence.

15. The controller of claim 8, wherein the drive circuitry comprises respective connections between the controller and the first and second transmitter electrodes.

16. The controller of claim 8, further configured to demodulate the resulting signals using the plurality of digital codes to thereby discriminate electrical effects produced by the first and second objects.

17. A position sensor comprising:

a plurality of transmitter electrodes;

a plurality of receiver electrodes; and

a controller coupled to the plurality of transmitter electrodes and to the plurality of receiver electrodes and configured to;

simultaneously transmit a first modulation signal with a first transmitter electrode and a second modulation signal with a second transmitter electrode, wherein the first and second modulation signals are distinct modulation signals based different ones of a plurality of distinct digital codes, and further wherein at least one of the plurality of distinct digital codes indicates driven and un-driven states;

receiving resultant signals with a plurality of receiver electrodes, wherein the resultant signals comprise electrical effects associated with the first and second modulation signals; and

determining a first position-based attribute of a first object and second position-based attribute of a second object based on the resultant signals.

18. The position sensor of claim 17, wherein the distinct digital codes are mathematically independent.

19. The position sensor of claim 17, wherein each of the plurality of distinct digital codes comprises one of a binary, ternary, and multi-level code.

20. The position sensor of claim 17, wherein the controller is configured to simultaneously transmit the first modulation signal with the first transmitter electrode and the second modulation signal with the second transmitter electrode by one of:

frequency modulating a carrier signal according to the distinct digital codes;

amplitude modulating a carrier signal according to the distinct digital codes; and

phase modulating a carrier signal according to the distinct digital codes.

21. The position sensor of claim 17, wherein each of the distinct digital codes comprises a code selected from the group consisting of Walsh-Hadamard codes, Gold codes, Kasami Codes, Barker Codes and Pseudo-Random codes.

22. The position sensor of claim 17, wherein the controller is further configured to generate the distinct digital codes by shifting a digital bit sequence.

23. The position sensor of claim 17, wherein the plurality of transmitter electrodes are disposed in a first direction and the plurality of receiver electrodes are disposed in a second direction substantially orthogonal to the second direction.

24. The position sensor of claim 17, wherein the controller is further configured to determine at least a partial image for an input object interacting with the position sensor.