Horizontal capacitively sensed pointing device

• US 8,125,445 B1
• Filed: 01/25/2008
• Issued: 02/28/2012
• Est. Priority Date: 01/26/2007
• Status: Active Grant

• Current Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Anderson, Erik
• Primary Examiner(s): Lao, Lun-Yi
• Assistant Examiner(s): SHENG, TOM V
• Application Number:
  US12/011,403
• Time in Patent Office: 1,495 Days
• Field of Search: 345/156, 345/157, 345/160, 345/161, 345/167, 345/184, 178/18.06, 178/19.03, 324/658, 324/686
• US Class Current: 345/157
• CPC Class Codes: G06F 3/0338 with detection of limited linear or angular displacement of an operating part of the device from a neutral position, e.g. isotonic or isometric joysticks

Abstract

Systems and methods for horizontal capacitively sensed pointing devices. Embodiments in accordance with the present invention capacitively sense planar movement with structures that are substantially perpendicular to the plane of movement. In accordance with a first embodiment of the present invention, a sensing mechanism for a pointing device operable to accept movement in a plane includes structures of the mechanism that are substantially perpendicular to the plane. The structures may include a parallel plate capacitor.

Claims

1. A capacitive sensing mechanism for a pointing device, comprising:

an inner moveable ring operable to accept movement parallel to a plane; and

an outer fixed ring substantially surrounding the inner moveable ring, wherein at least a portion of a surface for each of the inner moveable ring and the outer fixed ring is substantially perpendicular to said plane, and wherein a change in separation between said inner moveable ring and said outer fixed ring produces a change in capacitance of said sensing mechanism which forms a sensing signal for controlling the movement of the pointer.

2. The sensing mechanism of claim 1 wherein said inner moveable ring and outer fixed ring compose a parallel plate capacitor.

3. The sensing mechanism of claim 1 wherein said inner moveable ring resists movement perpendicular to said plane.

4. The sensing mechanism of claim 1 wherein said outer fixed ring comprises a plurality of metal segments electrically isolated from one another.

5. The sensing mechanism of claim 4 wherein said outer fixed ring comprises a non-conductive portion and wherein said metal segments are physically isolated from said inner moveable ring by the non-conductive portion of said outer fixed ring.

6. A capacitive sensing mechanism for a pointing device comprising:

an annular puck of non conducting material comprising a puck conductive material on its edge, wherein said puck has a puck radius; and

a circular ring having a radius of at least said puck radius, said circular ring surrounding said puck, wherein said circular ring comprises at least two ring conductive areas substantially in the plane of said puck and wherein said ring conductive areas are substantially in a plane of said puck conductive material, wherein further said ring conductive areas are electrically isolated from one another, and wherein a change in separation between said puck conductive material and said circular ring produces a change in capacitance of said capacitive sensing mechanism which forms a sensing signal for controlling the movement of the pointer.

7. The capacitive sensing mechanism of claim 6 wherein said puck is substantially cylindrical in shape.

8. The capacitive sensing mechanism of claim 6 wherein said puck conductive material is substantially the height of said puck.

9. The capacitive sensing mechanism of claim 8 wherein said ring conductive areas are substantially the height of said puck.

10. The capacitive sensing mechanism of claim 6 wherein said puck conductive material is electrically continuous.

11. The capacitive sensing mechanism of claim 6 wherein a sensed position of said position sensing mechanism is substantially insensitive to vertical force applied to said position sensing mechanism.

12. A capacitive sensing mechanism for a pointing device comprising:

an annular puck of non conducting material comprising a puck conductive material on its edge, wherein said puck has a puck radius; and

a circular ring having a radius of at least said puck radius, said circular ring surrounding said puck, wherein said circular ring comprises at least two ring conductive areas substantially in the plane of said puck and wherein said ring conductive areas are substantially in a plane of said puck conductive material, and wherein further said ring conductive areas are electrically isolated from one another, and wherein a change in separation between said puck conductive material and said circular ring produces a change in capacitance of said capacitive sensing mechanism which forms a sensing signal for controlling the movement of the pointer.

13. The capacitive sensing mechanism of claim 12 further comprising a pointing stick coupled to said annular puck, wherein movement of said pointing stick produces said change in separation between said puck conductive material and said circular ring.

14. The capacitive sensing mechanism of claim 12 wherein said circular ring provides mechanical restraint to said annular puck.

15. The capacitive sensing mechanism of claim 12 wherein said at least two ring conductive areas comprise at least eight ring conductive areas.

16. The capacitive sensing mechanism of claim 12 forming a parallel plate capacitor wherein said puck conductive material forms a first plate of said parallel plate capacitor and one of said at least two ring conductive areas forms a second plate of said parallel plate capacitor.

17. The capacitive sensing mechanism of claim 16 wherein movement of said puck results in a very small change in plate area of said capacitive sensing mechanism.

18. The capacitive sensing mechanism of claim 12 wherein a sensed position of said position sensing mechanism is substantially insensitive to vertical force applied to said position sensing mechanism.