Pointing device using capacitance sensor

• US 8,902,173 B2
• Filed: 09/24/2007
• Issued: 12/02/2014
• Est. Priority Date: 09/29/2006
• Status: Active Grant

• Current Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Seguine, Dennis
• Primary Examiner(s): HERNANDEZ, JESUS J
• Application Number:
  US11/903,878
• Publication Number:
  US 20080078590A1
• Time in Patent Office: 2,626 Days
• Field of Search: None
• US Class Current: 345/173
• CPC Class Codes: G06F 3/03548 Sliders, in which the moving part moves in a plane
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• 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

Apparatuses and methods for determining a deflection of a moveable conductive plate that is moved over a capacitive sensing device. The method may include moving the moveable conductive plate over sensor elements of the capacitive sensing device, and determining the deflection of the moveable conductive plate. In determining the deflection, a deflection magnitude and a deflection direction may be determined by calculating a vector of x- and y-directions or a vector of a radius and an angle.

Claims

1. A pointing device comprising:

a moveable object comprising a ring-shaped conductive surface;

a plurality of radial sensor elements in a ring configuration disposed on a substrate and configured to capacitively couple with the ring-shaped conductive surface of the moveable object, the ring configuration of the plurality of radial sensor elements having an outer circumference and an inner circumference, wherein the ring-shaped conductive surface is disposed in a default position such surface-area overlaps of the plurality of radial sensor elements and respective portions of the ring-shaped conductive surface are substantially equal, wherein the surface-area overlaps change when the moveable object is moved from the default position, and wherein the diameter of the ring-shaped conductive surface is greater than the diameter of the plurality of radial sensor elements;

a sensing area disposed within the inner circumference of the plurality of radial sensor elements and configured to capacitively couple with another conductive surface of the moveable object when a live hinge molded into the moveable object is depressed in a direction perpendicular to a first plane, wherein the other conductive surface is fixed to the live hinge; and

a processing device coupled to the substrate, the processing device configured to scan the plurality of radial sensor elements, sense movement of the moveable object parallel to the substrate based on changes in capacitances of the plurality of radial sensor elements and sense movement of the moveable object perpendicular to the substrate based on a change in capacitance of the sensing area, wherein the changes in capacitances of the plurality of radial sensor elements is caused by the changes in the surface-area overlaps of the respective portions of the ring-shaped conductive surface.

2. The pointing device of claim 1, further comprising a self-centering device coupled to the moveable object, wherein the self-centering device is configured to center the moveable object to the default position after being moved, wherein the self-centering device comprises a spring component.

3. The pointing device of claim 1, further comprising an insulating layer between the first plane and a second plane in which the moveable object is configured to move.

4. The pointing device of claim 1, wherein the plurality of radial sensor elements are disposed in a substantially circular pattern, wherein the moveable object comprises a conductive trace, wherein the outer circumference of the plurality of radial sensor elements in the substantially circular pattern is substantially aligned with the center of the conductive trace when the moveable object is in a default position, and wherein each of the plurality of radial sensor elements comprises a tapered shape that tapers towards the center of the substantially circular pattern.

5. The pointing device of claim 1, wherein the outer circumference of the plurality of radial sensor elements in the ring configuration is substantially aligned with the center of the conductive trace when the moveable object is in a default position, and further comprising a button disposed in the sensing area.

6. The pointing device of claim 1, further comprising a sensing element disposed in the sensing area and configured to detect the movement of the moveable object perpendicular to the first plane.

7. The pointing device of claim 1 further comprising a spring component configured to return the moveable object to the default position.

8. The pointing device of claim 7, wherein the single spring component is an o-ring of elastic material.

9. The pointing device of claim 7 further comprising a plurality of posts disposed to surround the outer circumference of the moveable object, wherein the spring component is a single spring disposed around the plurality of posts and at least in partial contact with the outer circumference of the moveable object.

10. An apparatus comprising:

a processing device configured to perform a plurality of scans to receive a plurality of signals from a plurality of radial sensor elements, the processing device configured to scan the plurality of radial sensor elements to determine a deflection of a moveable ring-shaped conductive plate, of a moveable object, that is moved relative to the plurality of radial sensor elements based on the plurality of signals;

the plurality of radial sensor elements in a ring configuration disposed in a first plane and configured to be used by the processing device to sense movement of the moveable ring-shaped conductive plate parallel to the first plane, the plurality of radial sensor elements disposed on a surface of a circuit board, the ring configuration of plurality of radial sensor elements having an outer circumference and an inner circumference, wherein the moveable ring-shaped conductive surface is disposed in a default position such that surface-area overlaps of the plurality of radial sensor elements and respective portions of the moveable ring-shaped conductive surface are substantially equal, wherein the surface-area overlaps change when the moveable object is moved from the default position, and wherein the diameter of the moveable ring-shaped conductive surface is greater than the diameter of the plurality of radial sensor elements;

a sensing area disposed on the surface of the circuit board and within the inner circumference of the plurality of radial sensor elements and configured to be used by the processing device to sense movement of a switch plate fixed to a live hinge molded into the moveable object, wherein the movement of the switch plate is perpendicular to the first plane when live hinge is depressed;

wherein the processing device is coupled to the circuit board;

a housing coupled to the circuit board, wherein circuit board is stationary relative to the housing; and

an insulating layer disposed between the plurality of radial sensor elements and the moveable conductive plate.

11. The apparatus of claim 10, wherein the housing, circuit board, and moveable object are disposed in a joystick of a keyboard.

12. The apparatus of claim 10, wherein the live hinge comprises a button configured to be depressed by perpendicular movement of a center switch plate coupled to the live hinge.

13. The apparatus of claim 10, further comprising a sensing element disposed in the sensing area and configured to detect the movement of the moveable object perpendicular to the first plane.

14. The apparatus of claim 10 further comprising the moveable ring-shaped conductive plate coupled to the housing by a spring component, wherein the spring component is configured to return the moveable conductive plate to a default position after being moved.

15. The apparatus of claim 14 further comprising a plurality of posts disposed to surround the outer circumference of the moveable conductive plate, wherein the spring component is a single spring disposed around the plurality of posts and at least in partial contact with the outer circumference of the moveable object.