CAPACITIVE TOUCH SCREEN HAVING DYNAMIC CAPACITANCE CONTROL AND IMPROVED TOUCH-SENSING

• US 20120092288A1
• Filed: 08/29/2011
• Published: 04/19/2012
• Est. Priority Date: 08/27/2010
• Status: Active Grant

• Current Assignee: UICO, Inc.
• Original Assignee: UICO, Inc.
• Inventors: Wadia, Bahar N.
• Granted Patent: US 8,866,793 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/04186 Touch location disambiguation
• CPC Class Codes: G06F 3/044 by capacitive means

Abstract

Methods and apparatus for improving the sensing performance of a capacitive touch screen sensing device. The electrical potential of conductive structures proximate capacitive touch pads of the sensing device is altered to compensate for the effect of parasitic capacitance, based on external conditions such as water on the touch screen or an intervening user worn glove. The compensation for parasitic capacitance improves the signal to noise ratio and therefore the sensing performance of the device.

Claims

1. A method of improving the sensing performance of a capacitive touch screen device including at least one capacitive touch pad element, the method comprising:

selectively altering a magnitude of an electrical potential of at least one electrically conductive structure proximate the at least one capacitive touch pad element based on an electrical potential of the at least one capacitive touch pad element, to alter an effective capacitance of the at least one capacitive touch pad element; and

subsequently detecting a user touch of the at least capacitive touch pad element.

2. The method of claim 1, wherein the electrical potential of the at least one electrically conductive structure is altered to substantially match the electrical potential of the at least one capacitive touch pad element.

3. The method of claim 1, wherein the electrical potential of the at least one electrically conductive structure is altered to a magnitude substantially different from the electrical potential of the at least one capacitive touch pad element.

4. The method of claim 1, further comprising disposing a plurality of electrically conductive elements proximate the at least one capacitive touch pad element.

5. The method of claim 4, wherein an electrical potential of each of the plurality of electrically conductive elements is altered based on the electrical potential of the at least one capacitive touch pad element.

6. The method of claim 1, wherein the capacitive touch screen includes a plurality of capacitive touch pad elements, and wherein a plurality of electrically conductive elements is disposed proximate each capacitive touch pad element of the plurality.

7. The method of claim 1, wherein the at least one electrically conductive element is another capacitive touch pad element disposed proximate the at least one capacitive touch pad element.

8. A capacitance touch sensing device, comprising:

a plurality of capacitive touch sensing pads operatively coupled with a processor for sensing a user touch;

at least one electrically conductive element disposed proximate each one of the plurality of capacitive touch sensing pads; and

apparatus for selectively altering a magnitude of an electrical potential of the conductive elements based on a magnitude of an electrical potential of the capacitive touch sensing pads and based on an expected external condition.

9. The capacitive touch sensing device of claim 8, wherein the expected external condition is the presence of water on the capacitive touch sensing device, and wherein the electrical potential of the electrically conductive elements is altered to substantially match the electrical potential of the capacitive touch sensing pads.

10. The capacitive touch screen device of claim 8, wherein the expected external condition is a user glove intervening between a user'"'"'s finger and the capacitive touch sensing pads, and wherein the electrical potential of the electrically conductive elements is altered to substantially match the electrical potential of the capacitive touch sensing pads.

11. The capacitive touch screen sensing device of claim 8, wherein the electrically conductive elements are other capacitive touch pads of the plurality of capacitive touch pads.

12. The capacitive touch screen sensing device of claim 8, wherein the electrically conductive elements are conductive structures separate from the capacitive touch pads.

13. The capacitive touch screen sensing device of claim 12, wherein the electrically conductive elements are formed on a same substrate as the capacitive touch pads.

14. A method of compensating for parasitic capacitance in a capacitive touch screen device including at least one capacitive touch pad element, the method comprising:

selectively altering a magnitude of an electrical potential of at least one electrically conductive structure proximate the at least one capacitive touch pad element based on an electrical potential of the at least one capacitive touch pad element; and

subsequently detecting a user touch of the at least capacitive touch pad element.

15. The method of claim 14, wherein the electrical potential of the at least one electrically conductive structure is altered to substantially match the electrical potential of the at least one capacitive touch pad element.

16. The method of claim 14, wherein the electrical potential of the at least one electrically conductive structure is altered to a magnitude substantially different from the electrical potential of the at least one capacitive touch pad element.

17. The method of claim 14, further comprising disposing a plurality of electrically conductive elements proximate the at least one capacitive touch pad element.

18. The method of claim 17, wherein an electrical potential of each of the plurality of electrically conductive elements is altered based on the electrical potential of the at least one capacitive touch pad element.

19. The method of claim 14, wherein the capacitive touch screen includes a plurality of capacitive touch pad elements, and wherein a plurality of electrically conductive elements is disposed proximate each capacitive touch pad element of the plurality.

20. The method of claim 14, wherein the at least one electrically conductive element is another capacitive touch pad element disposed proximate the at least one capacitive touch pad element.