Method and apparatus for improving capacitive sensing detection

• US 10,025,428 B2
• Filed: 11/19/2015
• Issued: 07/17/2018
• Est. Priority Date: 11/19/2015
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Khazeni, Kasra, Berget, Damien, Reynolds, Joseph Kurth
• Primary Examiner(s): DANIELSEN, NATHAN ANDREW
• Application Number:
  US14/946,746
• Publication Number:
  US 20170147141A1
• Time in Patent Office: 971 Days
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• CPC Class Codes: G06F 2203/04106 Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection
• 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 3/041662 using alternate mutual and self-capacitive scanning
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes

Abstract

Embodiments of the disclosure provided herein provide a device and method of using the device that is able to improve the detection of user input provided to an input device while one or more sources of noise are present during the detection process. One or more of the embodiments disclosed herein may include a scanning process and a signal processing technique that is able to more reliably detect the presence and position of an input object by reducing the effect of noise on a resulting signal that is generated during a capacitive sensing process. In some configurations, the scanning and signal processing techniques disclosed herein can be improved by increasing a capacitive sensing device'"'"'s ability to detect the presence of an input object by improving the signal-to-noise ratio of the data collected during a capacitive sensing process.

Claims

1. A method of detecting the position of an input object within a sensing region of an input device, comprising:

generating a first composite resulting signal, wherein the first composite resulting signal comprises a first sum of capacitive sensing measurements received from two or more sensor electrodes in a first scanned group of sensor electrodes in an array of sensor electrodes;

generating a second composite resulting signal, wherein the second composite resulting signal comprises a second sum of capacitive sensing measurements received from two or more sensor electrodes in a second scanned group of sensor electrodes in the array of sensor electrodes, wherein the two or more sensor electrodes in the first scanned group and the two or more sensor electrodes in the second scanned group have at least one sensor electrode in common; and

analyzing the first composite resulting signal and the second composite resulting signal to determine a resulting signal value from each of the sensor electrodes in the first scanned group and the second scanned group.

2. The method of claim 1, wherein the generated first composite resulting signal and the generated second composite resulting signal are formed using an absolute sensing type capacitive sensing technique.

3. The method of claim 1, wherein the array of sensor electrodes is one of a plurality of arrays of sensors electrodes that form at least part of a sensing region of the input device.

4. The method of claim 3, wherein each of the arrays of sensors electrodes in the plurality of arrays of sensors electrodes include the same number of sensor electrodes.

5. The method of claim 1, wherein analyzing the first composite resulting signal and the second composite resulting signal comprises:

inserting the first and second composite resulting signals into a measurement matrix; and

multiplying the measurement matrix times an inverted sample matrix, wherein the inverted sample matrix comprises a sampling pattern used to create the first scanned group and a sampling pattern used to create the second scanned group.

6. The method of claim 1, wherein the array of sensor electrodes comprises at least three sensor electrodes, and the first scanned group and the second scanned group comprise at least one less sensor electrode than the total number of sensor electrodes in the array of sensor electrodes.

7. The method of claim 1, further comprising:

forming a capacitive image during one scanning cycle of a sensing region of the input device, wherein the scanning cycle comprises a plurality of sequential and equal time intervals of a scanning sequence,

wherein the generated first composite resulting signal and the generated second composite resulting signal are each formed during the plurality of sequential and equal time intervals.

8. The method of claim 1, wherein the first composite resulting signal and the second composite signal are generated by a multiplexor assembly.

9. The method of claim 8, wherein the generated first composite resulting signal and the generated second composite resulting signal are each formed during one sequential and equal time interval.

10. A method of detecting the position of an input object within a sensing region of an input device, comprising:

calculating a resulting signal for each sensor electrode in a first array of sensor electrodes, wherein calculating the resulting signal comprises;

generating a first composite resulting signal, wherein the first composite resulting signal comprises a first sum of capacitive sensing measurements received from two or more sensor electrodes in a first scanned group of sensor electrodes in the first array of sensor electrodes;

generating a second composite resulting signal, wherein the second composite resulting signal comprises a second sum of capacitive sensing measurements received from two or more sensor electrodes in a second scanned group of sensor electrodes in the first array of sensor electrodes, wherein the two or more sensor electrodes in the first scanned group and the two or more sensor electrodes in the second scanned group have at least one sensor electrode in common; and

analyzing the first composite resulting signal and the second composite resulting signal to determine a resulting signal value from each of the sensor electrodes in the first scanned group and the second scanned group;

calculating a resulting signal for each sensor electrode in a second array of sensor electrodes, wherein calculating the resulting signal comprises;

generating a third composite resulting signal, wherein the third composite resulting signal comprises a third sum of capacitive sensing measurements received from two or more sensor electrodes in a third scanned group of sensor electrodes in the second array of sensor electrodes;

generating a fourth composite resulting signal, wherein the fourth composite resulting signal comprises a fourth sum of capacitive sensing measurements received from two or more sensor electrodes in a fourth scanned group of sensor electrodes in the second array of sensor electrodes; and

analyzing the third composite resulting signal and the fourth composite resulting signal to determine a resulting signal value from each of the two or more sensor electrodes in the second array of sensor electrodes; and

combining the calculated resulting signal for each sensor electrode in the first array and the second array to form at least part of a capacitive image of the sensing region of the input device.

11. The method of claim 10, wherein the generated first, second, third and fourth composite resulting signals are formed using an absolute sensing type capacitive sensing technique.

12. The method of claim 10, wherein the first and second arrays of sensor electrodes are two of a plurality of arrays of sensors electrodes that form the sensing region of the input device.

13. The method of claim 12, wherein each of the arrays of sensors electrodes in the plurality of arrays of sensors electrodes include the same number of sensor electrodes.

14. The method of claim 10, wherein analyzing the first composite resulting signal and the second composite resulting signal comprises:

inserting the first and second composite resulting signals into a measurement matrix; and

multiplying the measurement matrix times an inverted sample matrix, wherein the inverted sample matrix comprises a sampling pattern used to create the first scanned group and a sampling pattern used to create the second scanned group.

15. The method of claim 10, wherein the first and the second arrays of sensor electrodes comprise at least four sensor electrodes, and the first, second, third and fourth scanned groups comprise at least one less sensor electrode than the total number of sensor electrodes in the first and the second arrays of sensor electrodes.

16. An input device, comprising:

a processing system; and

a non-transitory memory having stored therein a number of instructions which, when executed by the processing system, causes the processing system to perform operations comprising;

generating a first composite resulting signal, wherein the first composite resulting signal comprises a first sum of capacitive sensing measurements received from two or more sensor electrodes in a first scanned group of sensor electrodes in an array of sensor electrodes;

generating a second composite resulting signal, wherein the second composite resulting signal comprises a second sum of capacitive sensing measurements received from two or more sensor electrodes in a second scanned group of sensor electrodes in the array of sensor electrodes, wherein the two or more sensor electrodes in the first scanned group and the two or more sensor electrodes in the second scanned group have at least one sensor electrode in common; and

analyzing the first composite resulting signal and the second composite resulting signal to determine a resulting signal value from each of the sensor electrodes in the first scanned group and the second scanned group.

17. The input device of claim 16, wherein the generated first composite resulting signal and the generated second composite resulting signal are formed using an absolute sensing type capacitive sensing technique.

18. The input device of claim 16, wherein the array of sensor electrodes is one of a plurality of arrays of sensors electrodes that form a sensing region of the input device.

19. The input device of claim 18, wherein each of the arrays of sensors electrodes in the plurality of arrays of sensors electrodes includes the same number of sensor electrodes.

20. The input device of claim 16, wherein analyzing the first composite resulting signal and the second composite resulting signal comprises:

inserting the first and second composite resulting signals into a measurement matrix; and

multiplying the measurement matrix times an inverted sample matrix, wherein the inverted sample matrix comprises a sampling pattern used to create the first scanned group and a sampling pattern used to create the second scanned group.

21. The input device of claim 16, wherein the array of sensor electrodes comprises at least four sensor electrodes, and the first scanned group and the second scanned group comprise at least one less sensor electrode than the total number of sensor electrodes in the array of sensor electrodes.