Floating capacitive couplers used to enhance signal coupling in a capacitive touchpad

• US 8,456,427 B2
• Filed: 03/31/2008
• Issued: 06/04/2013
• Est. Priority Date: 03/29/2007
• Status: Active Grant

• Current Assignee: Cirque Corporation
• Original Assignee: Cirque Corporation
• Inventors: Bytheway, Jared G.
• Primary Examiner(s): Dharia, Prabodh M
• Application Number:
  US12/059,842
• Publication Number:
  US 20080245582A1
• Time in Patent Office: 1,891 Days
• Field of Search: 345157-174, 345/55, 345/211, 178/18.06, 324658-660
• US Class Current: 345/173
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G06F 3/0448 Details of the electrode shape, e.g. for enhancing the detection of touches, for generating specific electric field shapes, for enhancing display quality

Abstract

A capacitive touchpad comprised of drive electrodes and at least one sense electrodes disposed on or within an insulating substrate material, wherein an electrically floating capacitive coupler is disposed adjacent to both the drive electrodes and the sense electrode to thereby enhance signal coupling between the drive electrodes and the sense electrode caused by introduction of a pointing object.

Claims

1. A method for increasing the effect of a pointing object that influences the coupling of a signal between electrodes of a capacitive sensor used in a touchpad, said method comprising:

1) providing at least one drive electrode for generating a signal and at least one sense electrode for measuring a portion of the signal that is coupled to the at least one sense electrode;

2) providing at least one permanently electrically floating capacitive coupler that is disposed so as to be in a fixed position relative to and adjacent to the at least one drive electrode and the at least one sense electrode, the floating capacitive coupler being disposed in a same plane and between the at least one drive electrode and the at least one sense electrode; and

3) introducing a pointing object so as to be in proximity of the at least one drive electrode and the at least one sense electrode, wherein a presence of the pointing object is sufficient to cause a change in coupling of a signal between the at least one drive electrode and the at least one sense electrode, wherein the at least one electrically floating capacitive coupler enhances the effect of the change in coupling of the signal whenever a low impedance path created between the at least one electrically floating capacitive coupler and the pointing object.

2. The method as defined in claim 1 wherein the method further comprises the step of causing a decrease in coupling of the signal between the at least one drive electrode and the at least one sense electrode when the pointing object is a conductive material.

3. The method as defined in claim 1 wherein the method further comprises the step of causing an increase in coupling of the signal between the at least one drive electrode and the at least one sense electrode when the pointing object is an insulating material.

4. The method as defined in claim 1 wherein the method further comprises the step of disposing the at least one drive electrode, the at least one sense electrode, and the at least one electrically floating capacitive coupler within an insulated substrate.

5. The method as defined in claim 4 wherein the method further comprises the step of disposing the at least one drive electrode, the at least one sense electrode and the at least one electrically floating capacitive coupler on three separate planes within the insulated substrate.

6. The method as defined in claim 4 wherein the method further comprises the step of disposing the at least one drive electrode, the at least one sense electrode and the at least one electrically floating capacitive coupler on two separate planes within the insulated substrate, wherein two of the three electrodes are disposed on the same plane.

7. The method as defined in claim 4 wherein the method further comprises the step of disposing the at least one drive electrode, the at least one sense electrode and the at least one electrically floating capacitive coupler on a single plane within the insulated substrate.

8. The method as defined in claim 5 wherein the method further comprises the step of disposing the at least one electrically floating capacitive coupler nearest to a surface of a capacitive sensor to thereby enhance the effect of the pointing object.

9. The method as defined in claim 1 wherein the method further comprises the step of reducing a voltage induced on the at least one sense electrode by the at least one drive electrode.

10. The method as defined in claim 1 wherein the method further comprises the step of increasing spacing between the at least one drive electrode and the at least one sense electrode without reducing the ability of the at least one drive electrode and the at least one sense electrode to function as part of a capacitive sensor.

11. A system for increasing the effect of a pointing object that influences the coupling of a signal between electrodes of a capacitive sensor in a touchpad, said system comprised of:

at least one drive electrode and means for generating a signal;

at least one sense electrode and means for measuring a portion of the signal that is coupled to the at least one sense electrode; and

at least one permanently electrically floating capacitive coupler that is in a fixed position relative to and disposed so as to be adjacent to the at least one drive electrode and the at least one sense electrode, the floating capacitive coupler being disposed in a same plane and between the at least one drive electrode and the at least one sense electrode such that when the pointing object is in proximity of the at least one drive electrode and the at least one sense electrode, the presence of the pointing object is sufficient to cause a change in coupling of a signal between the at least one drive electrode and the at least one sense electrode whenever a low impedance path is created between the at least one electrically floating capacitive coupler and the pointing object.

12. The system as defined in claim 11 wherein the system is further comprised of an insulated substrate, wherein the at least one drive electrode, the at least one sense electrode and the at least one electrically floating capacitive coupler are disposed within the insulated substrate.

13. The system as defined in claim 12 wherein the at least one drive electrode, the at least one sense electrode and the at least one electrically floating capacitive coupler are disposed on three separate planes within the insulated substrate.

14. The system as defined in claim 12 wherein the at least one drive electrode, the at least one sense electrode and the at least one electrically floating capacitive coupler are disposed on two separate planes within the insulated substrate, wherein two of the three electrodes are disposed on the same plane.

15. The system as defined in claim 12 wherein the at least one drive electrode, the at least one sense electrode and the at least one electrically floating capacitive coupler are disposed on a single plane within the insulated substrate.

16. The system as defined in claim 13 wherein the at least one electrically floating capacitive coupler is disposed nearest to a surface of a capacitive sensor.

17. The system as defined in claim 11 wherein spacing between the at least one drive electrode and the at least one sense electrode is increased without reducing the ability of the at least one drive electrode and the at least one sense electrode to function as part of a capacitive sensor.

18. The system as defined in claim 11 wherein the at least one electrically floating capacitive coupler is disposed adjacent to a plurality of drive electrodes and at least one sense electrode.

19. The system as defined in claim 11 wherein the at least one electrically floating capacitive coupler includes at least a portion that overlaps on a separate plane the at least one drive electrode and the at least one sense electrode.

20. The system as defined in claim 11 wherein the at least one electrically floating capacitive coupler includes at least a portion that is disposed immediately adjacent to an edge of the at least one drive electrode and the at least one sense electrode in a same plane.

21. The system as defined in claim 11 wherein the at least one drive electrode and the at least one sense electrode are disposed orthogonally to each other in separate planes of an insulated substrate.