Normalizing capacitive sensor array signals

• US 8,086,417 B2
• Filed: 07/03/2008
• Issued: 12/27/2011
• Est. Priority Date: 07/03/2007
• Status: Expired

• Current Assignee: Monterey Research, LLC (Vector Capital Corporation)
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Seguine, Ryan D.
• Primary Examiner(s): TSAI, CAROL S W
• Application Number:
  US12/167,552
• Publication Number:
  US 20090009194A1
• Time in Patent Office: 1,272 Days
• Field of Search: 702/105, 702/150, 702/158, 324/662, 324/664, 324/686, 324/684, 345/174, 345/173, 345/168, 345/157, 345/156, 345/176, 345/177, 345/178, 178/18.06, 178/18.07, 178/19.03, 178/18.01, 341/33, 341/10, 341/34, 200/600
• US Class Current: 702/105
• CPC Class Codes: G01D 5/24 by varying capacitance

Abstract

An embodiment of the present invention is directed to a method for processing a position signal. The method includes receiving a first position signal from a capacitive sensor and determining a proximity of the capacitive sensor to a connection of an array of capacitive sensors. The sensitivity of the capacitive sensor is then adjusted and a second position signal is received from the capacitive sensor. The second position signal may then be reported. The present invention facilitates more accurate readings from an array of capacitive sensors.

Claims

1. A method for reporting position information, the method comprising:

receiving position information regarding an interaction with a capacitive array, said position information originating from active sensors of said capacitive array;

accessing respective adjustment values corresponding to said active sensors, the respective adjustment values derived from the position information;

adjusting said position information based on said respective adjustment values corresponding to said active sensors to produce adjusted position information;

determining a position of said interaction based on said adjusted position information; and

reporting said position of said interaction.

2. The method of claim 1, wherein said respective adjustment values corresponding to said active sensors further are based on locations of said active sensors within said capacitive array.

3. The method of claim 1, wherein said adjusting comprises multiplying said position information said respective adjustment values.

4. The method of claim 1, wherein said position information comprises output values for said active sensors.

5. The method of claim 1, wherein said determining a position of said interaction comprises computing a centroid computation based on said adjusted position information.

6. The method of claim 1, wherein said sensor array comprises a high impedance substrate.

7. A system for processing position information, the system comprising:

a position signal receiver for receiving a first position signal from a capacitive sensor array;

a position information module for accessing sensitivity information corresponding to and derived from said first position signal;

a sensor sensitivity control module for adjusting the sensitivity of capacitance sensors within said capacitive sensor array corresponding to said sensitivity information; and

a position signal reporting module for determining a second position signal based on said capacitor sensor array with adjusted sensitivity.

8. The system of claim 7, wherein said sensitivity information corresponding with said first position signal comprises location information of active capacitive sensors within said capacitive sensor array.

9. The system of claim 7, wherein said position information module accesses a value for adjusting a sensitivity of a capacitive sensor.

10. The system of claim 7, wherein said sensor sensitivity control module adjusts the sensitivity of one or more active capacitive sensors.

11. The system of claim 7, wherein said sensor sensitivity control module adjusts the sensitivity of a plurality of sensors within said capacitive sensor array.

12. The system of claim 7, wherein said sensor sensitivity control module adjusts the sensitivity of one or more capacitive sensors by adjusting a scan time of said one or more capacitive sensors.

13. The system of claim 7, wherein said sensor sensitivity module adjusts the sensitivity of one or more capacitive sensors based on locations of said one or more capacitive sensors within said array of capacitive sensors.

14. A method for processing a position signal, the method comprising:

receiving a first position signal from a capacitive sensor of an array of capacitive sensors;

determining a proximity of a contact object to said capacitive sensor of an array of capacitive sensors;

adjusting a sensitivity of said capacitive sensor based on said proximity;

receiving a second position signal from said capacitive sensor having its sensitivity adjusted; and

reporting said second position signal.

15. The method of claim 14, wherein said adjusting of said sensitivity of said capacitive sensor comprises adjusting a scan time of said capacitive sensor.

16. The method of claim 14, wherein said adjusting of said sensitivity of said capacitive sensor comprises adjusting a current for charging a capacitor.

17. The method of claim 14, wherein said adjusting of said sensitivity of said capacitive sensor comprises adjusting a capacitance of a modification capacitor.

18. The method of claim 14, wherein said adjusting of said sensitivity of said capacitive sensor comprises adjusting a voltage threshold.

19. A method for processing a position signal, the method comprising:

receiving first position signals from a plurality of active capacitive sensors;

determining individual proximities of said plurality of active capacitive sensors to at least one contact object;

adjusting sensitivities of the active capacitive sensors based on said individual proximities;

receiving second position signals from said plurality of active capacitive sensors having their sensitivity adjusted; and

reporting said second position signals.

20. The method of claim 19, wherein said adjusting comprise individually adjusting scan times of said plurality of active capacitive sensors.

21. The method of claim 19, wherein said adjusting is based on said individual proximities of said plurality of active capacitive sensors.