Methods and systems for detecting a position-based attribute of an object using digital codes

• US 8,809,702 B2
• Filed: 02/11/2014
• Issued: 08/19/2014
• Est. Priority Date: 11/15/2005
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Reynolds, J. Kurth
• Primary Examiner(s): Nguyen, Kevin M
• Application Number:
  US14/177,566
• Publication Number:
  US 20140160071A1
• Time in Patent Office: 189 Days
• Field of Search: 345/173, 178/19.07, 178/18.04
• US Class Current: 178/18.06
• 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 controller configured to sense an input object in a sensing region of a sensing device, the controller comprising:

drive circuitry coupled to a first transmitter electrode and a second transmitter electrode and configured to simultaneously apply a first modulation signal to the first transmitter electrode and a second modulation signal to the second transmitter electrode, wherein the first modulation signal is based on a first one of a plurality of distinct digital codes and the second modulation signal is based on a second one of the plurality of distinct digital codes; and

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

wherein the controller is configured to determine positional information for the input object based on the on the resultant signals.

2. The controller of claim 1, wherein the controller is further configured to determine the positional information for a second input object in the sensing region based on the resultant signals.

3. The controller of claim 2, wherein the first and second input objects comprise fingers.

4. The controller of claim 2, wherein the first input object comprises a part of a human hand and the second input object comprises a stylus.

5. The controller of claim 2, wherein the controller is configured to reject information relating to the second input object.

6. The controller of claim 1, wherein the receive circuitry is configured to receive second resultant signals with the plurality of receiver electrodes and wherein the controller is further configured to adjust a frequency of the first and second modulation signals based on observed noise in the second resultant signals.

7. The controller of claim 1, wherein the drive circuitry is configured to simultaneously apply the first modulation signal to the first transmitter electrode and the second modulation signal to the second transmitter electrode during a first operating mode and simultaneously apply a third modulation signal to the first transmitter electrode and the second transmitter electrode during a second operating mode.

8. The controller of claim 1, further comprising:

a demodulator configured to demodulate the resultant signals.

9. The controller of claim 1, wherein the first one of the plurality of distinct digital codes comprises a shifted digital bit sequence of the second one of the plurality of distinct digital codes.

10. The controller of claim 1, wherein simultaneously applying the first modulation signal and the second modulation signal comprises frequency modulating a carrier signal according to the first one and the second one of the plurality of distinct digital codes.

11. The controller of claim 1, wherein simultaneously applying the first modulated signal and the second modulated signal comprises one of:

phase modulating a carrier signal according to the first one and the second one of the plurality of distinct digital codes; and

amplitude modulating a carrier signal according to the first one and the second one of the plurality of distinct digital codes.

12. The controller of claim 1, wherein the plurality of distinct digital codes are mathematically independent.

13. The controller of claim 1, wherein the plurality of distinct digital codes is selected from a group consisting of Pseudo-Random codes, Walsh-Hadamard codes, m-sequences, Gold codes, Kasami codes, Barker codes, and delay line multiple tap sequences.

14. The controller of claim 1, wherein the first one and the second one of the plurality of distinct digital codes define the first modulated signal to be in phase with the second modulated signal during a first time, and the first modulated signal to be out of phase with the second modulated signal during a second time.

15. The controller of claim 1, wherein the controller is further configured to determine proximity information for the first input object based on the resultant signals.

16. The controller of claim 1, wherein the controller is configured to determine a gesture based on the positional information for the first input object.

17. A sensing device comprising:

a plurality of transmitter electrodes;

a plurality of receiver electrodes; and

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

simultaneously apply a first modulation signal to a first transmitter electrode of the plurality of transmitter electrodes and a second modulation signal to a second transmitter electrode of the plurality of transmitter electrodes, wherein the first modulation signal is based on a first one of a plurality of distinct digital codes and the second modulation signal is based on a second one of the plurality of distinct digital codes;

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

determine positional information for each of a first input object and a second input object in a sensing region of the sensing device based on the on the resultant signals.

18. The sensing device of claim 17, wherein the plurality of transmitter electrodes and the plurality of receiver electrodes are configured to be non-moveable with respect to each other.

19. The sensing device of claim 17, wherein the plurality of transmitter electrodes and the plurality of receiver electrodes are disposed in a non-overlapping arrangement on one side of a substrate.

20. The sensing device of claim 17, wherein the plurality of transmitter electrodes and the plurality of receiver electrodes are disposed in an overlapping arrangement.

21. The sensing device of claim 17, wherein simultaneously applying the first modulated signal and the second modulated signal comprises one of:

frequency modulating a carrier signal according to the first one and the second one of the plurality of distinct digital codes;

phase modulating a carrier signal according to the first one and the second one of the plurality of distinct digital codes; and

amplitude modulating a carrier signal according to the first one and the second one of the plurality of distinct digital codes.

22. The sensing device of claim 17, wherein the plurality of distinct digital codes are mathematically independent.

23. The sensing device of claim 17, further comprising a substantially rigid surface disposed over the plurality of transmitter electrodes and the plurality of receiver electrodes.

24. The sensing device of claim 17, further comprising a plurality of signal paths configured to individually couple the controller with each of the transmitter electrodes, respectively.

25. The sensing device of claim 17, wherein the plurality of transmitter electrodes are disposed on a flexible substrate.

26. A method for capacitive sensing, the method comprising:

simultaneously applying a first modulation signal to a first transmitter electrode and a second modulation signal to a second transmitter electrode, wherein the first modulation signal is based on a first one of a plurality of distinct digital codes and the second modulation signal is based on a second one of the plurality of distinct digital codes;

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 positional information for an input object based on the on the resultant signals.

27. The method of claim 26, further comprising:

determining positional information for a second input object based on the resultant signals; and

rejecting the positional information relating to the second object.

28. The method of claim 26, further comprising receiving second resultant signals with the plurality of receiver electrodes and wherein the controller is further configured to adjust a frequency of the first and second modulation signals based on observed noise in the second resultant signals.

29. The method of claim 26, further comprising simultaneously applying a first modulation signal to the first transmitter electrode and a second modulation signal to the second transmitter electrode during a first operating mode, and simultaneously applying a third modulation signal to the first transmitter electrode and the second transmitter electrode during a second operating mode.

30. The method of claim 26, further comprising determining a gesture based on the positional information for the first input object.