Technique for increasing the sensitivity of capacitive sensor arrays

• US 20080024455A1
• Filed: 07/25/2006
• Published: 01/31/2008
• Est. Priority Date: 07/25/2006
• Status: Active Grant

• Current Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Lee, Mark R., Seguine, Ryan D.
• Granted Patent: US 9,507,465 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G01D 5/2417 by varying separation
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/04847 Interaction techniques to control parameter settings, e.g. interaction with sliders or dials

Abstract

A technique for operating a capacitive sensor array. The technique includes logically grouping capacitance sensors of an array of capacitance sensors into sensor groups. The sensor groups each include at least two capacitance sensors of the array of capacitance sensors. Values indicative of a capacitance for each of the sensor groups are measured. The measured values are then analyzed to determine a location of a user interaction with the array of capacitance sensors.

Claims

1. A method, comprising:

logically grouping capacitance sensors of an array of capacitance sensors into sensor groups, wherein each sensor group includes at least two of the capacitance sensors;

measuring a value indicative of a capacitance for each of the sensor groups; and

analyzing the values of the sensor groups to determine a location of a user interaction with the array of capacitance sensors.

2. The method of claim 1, wherein logically grouping the capacitance sensors comprises sequentially connecting the sensor groups to a shared capacitance sensor circuit, wherein each of the sensor groups comprises a temporal electrical connection between a different set of two or more of the capacitance sensors.

3. The method of claim 1, further comprising assigning the value measured for each of the sensor groups to a particular capacitance sensor within each corresponding one of the sensor groups.

4. The method of claim 3, wherein the sensor groups include physically adjacent capacitance sensors within the array of capacitance sensors.

5. The method of claim 4, wherein the sensor groups each comprise an odd number of the capacitance sensors and wherein assigning the value measured for each of the sensor groups to the particular capacitance sensor within each corresponding one of the sensor groups comprises assigning the value measured for each of the sensor groups to a middle capacitance sensor of each corresponding one of the sensor groups.

6. The method of claim 4, wherein adjacent sensor groups include at least one common capacitance sensor.

7. The method of claim 1, wherein analyzing the values of the sensor groups comprises interpolating a center of the location of the user interaction with the array of capacitance sensors based on the values.

8. The method of claim 1, wherein the array of capacitance sensors comprises a linear slider of a user interface.

9. The method of claim 1, wherein the array of capacitance sensors comprises a circular slider of a user interface.

10. The method of claim 1, wherein the array of capacitance sensors comprises a touch pad of a user interface.

11. The method of claim 1, further comprising:

discretely scanning each of the capacitance sensors within the array of capacitance sensors individually; and

determining an approximate location of the user interaction based on the scanning,

wherein measuring the value indicative of the capacitance for each of the sensor groups comprises measuring the value indicative of the capacitance for a portion of the sensor groups localized about the approximate location to more precisely determine the location after discretely scanning each of the capacitance sensors,

wherein the portion of the sensor groups is less than all of the sensor groups within the array of capacitance sensors.

12. A machine-readable medium that provides instructions that, if executed by a machine, will cause the machine to perform operations comprising:

measuring a value indicative of a combined capacitance of a sensor group including two or more capacitance sensors of an array of capacitance sensors;

scanning the array of capacitance sensors to obtain a plurality of values corresponding to a plurality of sensor groups each including two or more capacitance sensors within the array of capacitance sensors; and

determining a location of a user interaction with the array of capacitance sensors based on the plurality of values.

13. The machine-readable medium of claim 12, wherein the sensor groups include physically adjacent capacitance sensors.

14. The machine-readable medium of claim 13, wherein adjacent sensor groups include at least one common capacitance sensor.

15. The machine-readable medium of claim 12, further providing instructions that, if executed by the machine, will cause the machine to perform further operations, comprising:

discretely scanning each of the capacitance sensors within the array of capacitance sensors individually; and

determining an approximate location of the user interaction based on the scanning,

wherein scanning the array of capacitance sensors to obtain the plurality of values comprises scanning a portion of the array of capacitance sensor to obtain the plurality of values corresponding to sensor groups localized about the approximate location to more precisely determine the location after discretely scanning each of the capacitance sensors,

wherein the portion of the sensor groups is less than all of the sensor groups within the array of capacitance sensors.

16. An apparatus, comprising:

a processing device;

a user interface including an array of capacitance sensors coupled to the processing device; and

a memory unit coupled to the processing device, the memory unit having stored therein instructions that, if executed by the processing device, will cause the processing device to perform operations comprising;

measuring a value indicative of a combined capacitance of a sensor group including two or more capacitance sensors within the array of capacitance sensors;

scanning the array of capacitance sensors to obtain a plurality of values corresponding to a plurality of sensor groups each including two or more capacitance sensors within the array of capacitance sensors; and

determining a location of a user interaction with the array of capacitance sensors based on the plurality of values.

17. The apparatus of claim 16, wherein the sensor groups include physically adjacent capacitance sensors and wherein adjacent sensor groups include at least one common capacitance sensor.

18. The apparatus of claim 16, wherein the processing device includes:

a capacitance sensor coupled to measure the plurality of values; and

an analog multiplexer bus coupled to sequentially couple the plurality of sensor groups to the capacitance sensor.

19. The apparatus of claim 18, wherein the capacitance sensor includes a relaxation oscillator circuit.

20. The apparatus of claim 19, wherein the user interface comprises one of a linear slider, a circular slider, or a touch pad.