Electret stylus for touch-sensor device

• US 9,285,930 B2
• Filed: 05/09/2008
• Issued: 03/15/2016
• Est. Priority Date: 05/09/2007
• Status: Active Grant

• Current Assignee: Wacom Co Limited (Wacom)
• Original Assignee: Wacom Co Limited (Wacom)
• Inventors: Grivna, Edward L.
• Primary Examiner(s): HARRIS, DOROTHY H
• Application Number:
  US12/151,858
• Publication Number:
  US 20120043142A1
• Time in Patent Office: 2,867 Days
• Field of Search: 178/19.3, 178/19.03, 345/179
• US Class Current: 1/1
• CPC Class Codes: G06F 3/03545 Pens or stylus

Abstract

A method and apparatus to couple a piece of electret material to a touch-sensor device stylus, where the electret material emits an electrostatic field to be sensed by a touch-sensor device.

Claims

1. A touch-sensor device stylus, comprising:

a body having a first end and a second end;

a piece of electret material coupled to the first end of the body, wherein the piece of electret material emits a first field to be sensed by a capacitive touch-sensor device by measuring an effect of the first field emitted by the piece of electret material on a second field emitted by the capacitive touch-sensor device, wherein the effect of the first field is determined by comparing a combined field that is formed by an interference of the first field emitted by the piece of electret material with the second field emitted by the capacitive touch-sensor device to the second field, wherein the effect of the first field is used to determine a position of the touch-sensor device stylus, and wherein the piece of electret material comprises a metal core in the piece of electret material that is associated with a direction of the first field, and wherein the piece of electret material further comprises a metal probe that is coupled to the metal core and extends out of the piece of electret material to couple the piece of electret material to the body of the touch-sensor device stylus; and

a socket to receive the first end of the body, wherein an interior surface of the socket is lined with a conductive material to contact a surface of the piece of electret material to short the surface of the piece of electret material emitting the first field when the first end of the body is inserted into the socket.

2. The touch-sensor device stylus of claim 1, wherein the piece of electret material at the first end of the body tapers to a point.

3. The touch-sensor device stylus of claim 1, wherein the second end of the body comprises a handle.

4. An apparatus comprising the touch-sensor device stylus of claim 1, wherein the socket is within the capacitive touch-sensor device.

5. The apparatus of claim 4, wherein the conductive material is disposed within the socket to contact substantially an entire surface of the piece of electret material.

6. The touch-sensor device stylus of claim 1, wherein the piece of electret material comprises a fluoropolymer.

7. The touch-sensor device stylus of claim 1, wherein the piece of electret material comprises a wax.

8. The touch-sensor device stylus of claim 1, wherein the piece of electret material comprises a resin.

9. The touch-sensor device stylus of claim 1, wherein the piece of electret material comprises polypropylene.

10. The touch-sensor device stylus of claim 1, wherein the piece of electret material comprises a synthetic polymer.

11. The touch-sensor device stylus of claim 1, wherein the first field is an electrostatic field, and wherein the second field is generated by a charge being driven through conductors of the capacitive touch-sensor device.

12. A method, comprising

providing a touch-sensor device stylus having a piece of electret material coupled to a first end of the stylus;

emitting a first field from the piece of electret material to be sensed by a capacitive touch-sensor device by measuring an effect of the first field emitted by the piece of electret material on a second field emitted by the capacitive touch-sensor device, and wherein the effect of the first field is determined by comparing a combined field that is formed by an interference of the first field emitted by the piece of electret material with the second field emitted by the capacitive touch-sensor device to the second field, wherein the effect of the first field is used to determine a position of the touch-sensor device stylus, wherein the piece of electret material comprises a metal core in the piece of electret material that is associated with a direction of the first field, and wherein the piece of electret material further comprises a metal probe that is coupled to the metal core and extends out of the piece of electret material to couple the piece of electret material to a body of the touch-sensor device stylus; and

providing a socket to receive the first end of the touch-sensor device stylus, wherein an interior surface of the socket is lined with a conductive material to contact a surface of the piece of electret material to short the surface of the piece of electret material emitting the first field when the first end of the touch-sensor device stylus is inserted into the socket.

13. The method of claim 12, further comprising:

sensing the first field from the piece of electret material and determining the position of the stylus in relation to the capacitive touch-sensor device.

14. The method of claim 13, wherein determining the position of the stylus comprises comparing the second field produced by the capacitive touch-sensor device to the combined field produced by the capacitive touch-sensor device and the piece of electret material.

15. The method of claim 12, wherein the capacitive touch-sensor device is a touchpad device.

16. The method of claim 12, wherein the capacitive touch-sensor device is a touch screen device.

17. The method of claim 12, wherein the first field is an electrostatic field, and wherein the second field is generated by a charge being driven through conductors of the capacitive touch-sensor device.

18. A method, comprising:

providing a body of a touch-sensor device stylus having a first end and a second end;

coupling a piece of electret material to the first end of the body, wherein the piece of electret material emits a first field to be sensed by a capacitive touch-sensor device by measuring an effect of the first field emitted by the piece of electret material on a second field emitted by the capacitive touch-sensor device, wherein the effect of the first field is determined by comparing a combined field that is formed by an interference of the first field emitted by the piece of electret material with the second field emitted by the capacitive touch-sensor device to the second field, and wherein the effect of the first field is used to determine a position of the touch-sensor device stylus, and wherein the piece of electret material comprises a metal core in the piece of electret material that is associated with a direction of the first field, and wherein the piece of electret material further comprises a metal probe that is coupled to the metal core and extends out of the piece of electret material to couple the piece of electret material to the body of the touch-sensor device stylus; and

providing a socket to receive the first end of the body, wherein an interior surface of the socket is lined with a conductive material to contact a surface of the piece of electret material to short the surface of the piece of electret material emitting the first field when the first end of the body is inserted into the socket.

19. The method of claim 18, wherein coupling the piece of electret material to the first end of the body comprises affixing the piece of electret material to the first end of the body.

20. The method of claim 18, wherein the piece of electret material comprises a fluoropolymer.