Position sensing computer input device

• US 5,365,461 A
• Filed: 04/30/1992
• Issued: 11/15/1994
• Est. Priority Date: 04/30/1992
• Status: Expired due to Term

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: MicroTouch Systems, Inc. (3M Company)
• Inventors: Stein, Robert A., Woringer, Charles A., Logan, James D.
• Primary Examiner(s): Harvey, Jack B.
• Assistant Examiner(s): Peeso, Thomas
• Application Number:
  US07/860,054
• Time in Patent Office: 929 Days
• Field of Search: 364/550, 178/19
• US Class Current: 700/298
• CPC Class Codes: G01B 7/004 for measuring coordinates of points

Abstract

A position sensing computer input device including a sensor with a sensing surface including a conductive sheet on which a human touch and the touch of an inanimate object may both be sensed. The device is able to discriminate between the two types of touch for allowing input with at least one of an inanimate object and a human touch.

Claims

1. A position sensing input device, comprising:

a sensor having on analog sensing surface and including a single layer of one or more conductive sheets;

means for detecting without electromagnetic radiation either a human touch or the touch of an inanimate object or both on said sensor; and

means for discriminating between the two types of touch for allowing input with at least one of an inanimate object and a human touch.

2. The input device of claim 1 in which said sensor includes an insulative substrate with a single conductive surface coating.

3. The input device of claim 1 in which said means for detecting a human touch includes means for supplying current to each said conductive sheet.

4. The input device of claim 3 in which said means for detecting a human touch further includes means for determining the current flow to each said conductive sheet responsive to the human touch.

5. The input device of claim 3 in which said current is time-varying.

6. The input device of claim 2 in which said inanimate object is conductive.

7. The input device of claim 6 in which said means for detecting an inanimate object touch includes means for supplying a current to said inanimate object.

8. The input device of claim 7 in which said means for detecting an inanimate object touch further includes means for determining the current flow through said inanimate object into said conductive surface coating responsive to the inanimate object touch on said sensing sensor surface.

9. The input device of claim 1 in which said means for discriminating includes means for alternately enabling said means for detecting a human touch and said means for detecting an inanimate object touch.

10. The input device of claim 1 in which said means for discriminating includes means for detecting the inanimate object touch when that touch is concurrent with a human touch to establish touch priority to the inanimate object touch.

11. The input device of claim 1 further including means for determining the inanimate touch location on said surface.

12. The input device of claim 9 in which said means for alternately enabling includes a switch.

13. The input device of claim 12 in which said switch is mounted on the inanimate object for operator control.

14. The input device of claim 9 in which said means for alternately enabling includes means for resolving human touch on the inanimate object.

15. The input device of claim 14 in which said means for resolving includes one or more capacitive sensors.

16. The input device of claim 14 in which said means for resolving includes a pair of resistive contacts.

17. The input device of claim 9 in which said means for alternately enabling includes means for determining the relative attitude of said inanimate object.

18. The input device of claim 17 in which said means for determining the relative attitude includes a tilt-sensitive switch for said inanimate object.

19. The input device of claim 9 in which said means for alternately enabling includes a sensor in an inanimate-object holding device.

20. The input device of claim 1 further including means for determining the human touch location on said surface.

21. The input device of claim 5 in which said means for determining the current flow includes means for detecting current out of phase with the voltage.

22. The input device of claim 8 in which said means for determining the current flow includes means for detecting current in phase with the voltage.

23. The input device of claim 1 in which said means for detecting includes a phase-sensitive detector.

24. The input device of claim 1 further including means for allowing human or inanimate object touch selection of discrete portions of said sensor for providing preestablished touch-sensitive areas.

25. The input device of claim 1 in which said means for detecting includes separate human touch and inanimate object touch sensors aligned to accurately report touch prints.

26. The input device of claim 1 further including means for calibrating touch position of both a human touch and an inanimate-object touch.

27. A position sensing input device, comprising:

an insulative substrate with a single conductive surface coating;

means for supplying time-varying current to said surface coating;

means for resolving current flow to said surface coating out of phase with the supply voltage responsive to a human touch on said surface coating for detecting the human touch;

a conductive stylus;

means for supplying time-varying current to said stylus;

means for resolving current flow from said stylus to said surface coating in phase with the supply voltage responsive to stylus touch on said surface coating for detecting the stylus touch; and

means for discriminating between the human and stylus touch for allowing input with at least one of said stylus and a human touch.

28. The input device of claim 27 in which said means for supplying time-varying current to said surface coating and said means for resolving current flow from said stylus to said surface coating includes a current buffer.

29. A position sensing input device, comprising:

an insulative substrate with a single conductive surface coating;

means for supplying time-varying current to said surface coating;

means for resolving current flow to said surface coating out of phase with the supply voltage responsive to a human touch on said surface coating for detecting the human touch;

a conductive stylus;

means for supplying time-varying current to said stylus;

means for resolving current flow from said stylus to said surface coating in phase with the supply voltage responsive to stylus touch on said surface coating for detecting the stylus touch; and

means for alternately enabling said means for resolving current flow to said surface coating responsive to a human touch and said means for resolving current flow from said stylus to said surface coating for discriminating between the two types of touch.

30. The input device of claim 29 in which said means for alternately enabling includes means for detecting stylus touch when that touch is concurrent with human touch to establish touch priority to the stylus touch.

31. A position sensing input device, comprising:

a sensor having an analog sensing surface;

an input stylus;

means for detecting without electromagnetic radiation either a human touch or a stylus touch or both on said sensor;

means for determining when the stylus is being used; and

means, responsive to said means for determining, for reporting only stylus touch points when said stylus is being used, to allow the user to physically touch the sensing surface while using the stylus.