Sliding contact control switch pad

• US 5,367,199 A
• Filed: 09/15/1992
• Issued: 11/22/1994
• Est. Priority Date: 05/01/1992
• Status: Expired due to Fees

• Current Assignee: Trial Technologies, Inc.
• Original Assignee: Trial Technologies, Inc.
• Inventors: Lefkowitz, Leonard R., Armstrong, Albert L. Jr.
• Primary Examiner(s): Pellinen, A. D.
• Assistant Examiner(s): Krishnan, Aditya
• Application Number:
  US07/944,918
• Time in Patent Office: 798 Days
• Field of Search: 307/112, 307/116, 340/517, 340/524, 340/806-807, 340/549, 200/DIG. 2
• US Class Current: 307/116
• CPC Class Codes: G06F 2203/04809 Textured surface identifying touch areas, e.g. overlay structure for a virtual keyboard
• CPC Class Codes: G06F 3/03547 Touch pads, in which fingers can move on a surface
• CPC Class Codes: H03K 17/9622 using a plurality of detectors, e.g. keyboard
• CPC Class Codes: H03K 2217/96066 Thumbwheel, potentiometer, scrollbar or slider simulation by touch switch

Abstract

A controller is provided which includes a plurality of equally spaced sensors disposed symmetrically about an intersection of at least two orthogonal axes and spaced from such axes by a null zone which is concentric with such sensors. Control circuitry is electrically connected to the sensors to control movement of a controlled object in a direction which is related to the position of an operator'"'"'s finger and the like relative to such intersection.

Claims

1. A sliding contact touch activated switch pad, comprising:

a plurality of sensors disposed about an intersection of at least two intersecting axes, each sensor of said plurality of sensors being a capacitive sensor and being separated from an adjacent sensor of said plurality of sensors by a non-conductive area;

a null zone disposed concentric with said plurality of sensors and located between said intersection and said plurality of sensors; and

means electrically connected to each sensor for producing (a) a final first-output signal when a controlling object is in conductive engagement with a sensor or a pair of adjacent sensors, and (b) a final second-output signal when said controlling object is not in conductive engagement with a sensor or pair of sensors.

2. The sliding contact touch activated switch pad of claim 1 wherein there are two intersecting axes which are orthogonal axes.

3. The sliding contact touch activated switch pad of claim 1 wherein said plurality of sensors comprise a ring-like configuration of capacitive sensors disposed symmetrically about said intersection, each sensor of said ring-like configuration of capacitive sensors being separated from an adjacent sensor of said ring-like configuration of capacitive sensors by a non-conductive strip.

4. The sliding contact touch activated switch pad of claim 3 wherein said producing means is electrically connected to each sensor of said ring-like configuration of capacitive sensors for producing (a) a final-first output signal when a controlling object is in conductive engagement with at least one sensor, and (b) a final second output-signal when said controlling object is not in conductive engagement with a sensor.

5. The sliding contact touch activated switch pad of claim 4 wherein said non-conductive strip is radially oriented relative to said intersection.

6. The sliding contact touch activated switch pad of claim 1 wherein said plurality of sensors comprise a ring-like configuration of four capacitive electrodes, each electrode of said four capacitive electrodes occupying substantially all of a quadrant of said ring-like configuration, said four capacitive electrodes being arranged symmetrically about said intersection, each electrode being separated from an adjacent electrode by a non-conductive strip.

7. The sliding contact touch activated switch pad of claim 1 wherein said plurality of sensors and said null zone are part of an upper surface of a housing, and further comprising means adjacent said upper surface for guiding said controlling object relative to said plurality of sensors.

8. The sliding contact touch activated switch pad of claim 7 wherein said guiding means comprises a plurality of raised ribs which are selectively disposed upon said upper surface.

9. The sliding contact touch activated switch pad of claim 8 wherein said guiding means also comprises a plurality of indentations which are selectively disposed upon said upper surface.

10. The sliding contact touch activated switch pad of claim 8 wherein said guiding means comprises a plurality of raised ribs which are selectively disposed upon said upper surface.

11. The sliding contact touch activated switch pad of claim 1 wherein one output signal is a logic low signal and the other output signal is a logic high signal.

12. The sliding contact touch activated switch pad of claim 11 wherein said producing means includes (a) a respective resistor electrically connected to each sensor and (b) means electrically connected to each respective resistor for applying a stream of narrow-negative going voltage pulses to each respective sensor through a respective resistor, said logic low signal being produced when the voltage value of a sensor is greater than a fixed threshold value at the time of sampling, which results from said controlling object being in conductive engagement with a sensor, and said logic high signal being produced when the voltage value of a respective sensor is less than said fixed threshold value at the time of sampling which results from said controlling object not being in conductive engagement with a sensor.

13. The sliding contact touch activated switch pad of claim 12 wherein said first final-output signal is a logic low signal and said second final-output signal is a logic high signal.

14. The sliding contact touch activated switch pad of claim 1, wherein said producing means includes a plurality of dedicated capacitance sensing circuits, each dedicated capacitance sensing circuit of said plurality of dedicated capacitance sensing circuits being electrically connected to a respective sensor, each dedicated capacitance sensing circuit producing (a) a final first-output signal when a controlling object is in conductive engagement with a respective sensor, and a final second-output signal when said controlling object is not in conductive engagement with a respective sensor.

15. The sliding contact touch activated switch pad of claim 14 wherein each dedicated capacitance sensing circuit includes a respective resistor electrically connected to a respective sensor and wherein said producing means further includes means electrically connected to each respective resistor for applying a stream of narrow voltage pulses to each respective sensor through a respective resistor, said final first-output signal being produced when the voltage value of a respective sensor at the time of sampling, is greater than a fixed threshold value, and said final second-output signal being produced when the voltage value of a respective sensor at the time of sampling is less than said fixed threshold value.

16. The sliding contact touch activated switch pad of claim 15 wherein one final output signal is a logic low signal and the other final output signal is a logic high signal.

17. The sliding contact touch activated switch pad of claim 16 wherein each dedicated capacitance sensing circuit includes means for preventing occasional noise input at a respective sensor from affecting said first final-output signal and said second final-output signal.

18. The sliding contact touch activated switch pad of claim 17 wherein said preventing means is a voltage-time integrating low-pass filter.

19. The sliding contact touch activated switch pad of claim 15 wherein each dedicated capacitance sensing circuit includes means for sampling periodically the state of the switch pad and providing an output signal state that is representative of the time average of more than 10 consecutive samplings.

20. The sliding contact touch activated switch pad of claim 15 wherein each dedicated capacitance sensing circuit includes means for providing a plurality of output signals each the result of time averaging, via a low pass filter, of more than 10 samplings of the respective sensor pad, such samplings made by applying a narrow negative voltage pulse to the sensor pad through a resistor and latching the condition of whether or not the pad voltage exceeded a threshold voltage at the end of the pulse, the final output value of said final first-output signals and said final second output signals being dependent upon the cumulative results of the voltage-time integration of said samplings.

21. The sliding contact touch activated switch pad of claim 15 wherein each dedicated capacitance sensing circuit includes means for excluding signals representing unwarranted activation of one or more of said sensors.

22. The sliding contact touch activated switch pad of claim 15 wherein each dedicated capacitance sensing circuit includes means for excluding signals representing the coincident activation of more than two physically adjacent sensors.

23. The sliding contact touch activated switch pad of claim 15 wherein each dedicated capacitance sensing circuit includes means for excluding signals representing the coincident activation of opposing sensor pads.

24. In a sliding contact touch activated switch pad wherein conductive engagement of one or more sensors by a controlling object causes a final control switching response, wherein the improvement comprises:

means disposed about a point for conductive engagement by a controlling object, including a plurality of sensors disposed about said point, each sensor being separated from an adjacent sensor by a non-conductive strip, each sensor being of sufficient size to accommodate placement of said controlling object thereon to effect a final control switching response without causing a final control switching response in another sensor of said plurality of sensors; and

means disposed between said point and said conductive engagement means for non-conductive engagement by said controlling object, including a surface of sufficient size to accommodate placement of said controlling object thereon without affecting a final control switching response in any sensor of said plurality of sensors.

25. The sliding contact touch activated switch pad of claim 24 wherein said point is located at the intersection of at least two intersecting axes and said plurality of sensors is disposed symmetrically about said intersection.

26. The sliding contact touch activated switch pad of claim 24 wherein each sensor comprises a side adjacent said non-conductive engagement means, said sides collectively enclosing said non-conductive engagement means, each side being of sufficient size to accommodate sliding passage of said controlling object to and from a respective sensor without causing a final control switching response in another sensor of said plurality of sensors .

27. The sliding contact touch activated switch pad of claim 26 wherein said surface is at least 0.66 inches wide in any direction.

28. The sliding contact touch activated switch pad of claim 26 wherein each side is at least one half inch wide.

29. The sliding contact touch activated switch pad of claim 26 wherein said surface has a perimeter which is at least equal to the number of adjoining sensors multiplied by one half inch.

30. The sliding contact touch activated switch pad of claim 26 wherein said surface includes a pressure actuated switch.

31. The sliding contact touch activated switch pad of claim 24 wherein said plurality of sensors is disposed about said point in a racetrack configuration, said surface being elongated.

32. The sliding contact touch activated switch pad of claim 26 further including means electrically connected to said conductive engagement means for directing a controlled object in a manner which is dependent upon the position of said controlling object relative to said non-conductive engagement means when said controlling object engages said conductive engagement means.

33. A controller comprising a plurality of electrically independent conductive touch sensitive electrodes surrounding a non-conductive center null zone of sufficient size to accommodate an operator'"'"'s digit pad thereon without affecting final control output response of any of said electrodes, each of said electrodes being switch responsive to the placement of at least a part of the operator'"'"'s digit pad thereon, so as to produce a single final output switch response that is indicative of the position of the operator'"'"'s digit pad with respect to the null zone when a single electrode is touched, and a dual final output switch response that is indicative of the position of the operator'"'"'s digit pad with respect to the null zone when at least a part of the operator'"'"'s digit pad comes in contact with each of a pair of adjacent electrodes.