Touchpad with dual sensor that simplifies scanning

• US 5,543,589 A
• Filed: 05/23/1994
• Issued: 08/06/1996
• Est. Priority Date: 05/23/1994
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Eardley, Richard A., Tizzard, Anthony R., Buchana, William A., Utley, Brian G.
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): Shankar, Vijay
• Application Number:
  US08/247,730
• Time in Patent Office: 806 Days
• Field of Search: 178/18-20, 345/173-175, 345/179
• US Class Current: 178/18.03
• CPC Class Codes: H03K 17/9618 using a plurality of detectors, e.g. keyboard

Abstract

Disclosed is a dual sensor comprising first and second touchpad sensors having different resolutions and being sandwiched to form a single sensor. Each of the touchpad sensors include a first plurality of electrically conductive strips positioned proximate to a second plurality of electrically conductive strips. The conductive strips in each plurality lie substantially in a single plane and the two pluralities are skewed relative to one-another in plan view. The conductive strips are separated by insulators that extend beyond the surface of the conductors to separate the conductors of one plurality from the conductors of the other plurality until a localized pressure is applied to a region of the pad. Two such touchpad sensors are sandwiched to form the dual sensor of the present invention. The two touchpad sensors are configured and positioned such that a single touch of a finger, stylus, or the like is capable of being detected by both sensors.

Claims

1. A dual sensor comprising:

(a) a first touchpad sensor having first and second pluralities of conductors associated therewith, and a first touchpad resolution; and

(b) a second touchpad sensor substantially the same size as said first touchpad sensor, having a second touchpad resolution, and positioned proximate to said first touchpad sensor, said second touchpad sensor having third and fourth pluralities of conductors associated therewith;

(1) wherein said first touchpad resolution is different from said second touchpad resolution; and

(2) wherein said first and second touchpad sensors are configured and positioned such that a single touch of a finger, stylus, or the like is detectable by both said first touchpad sensor and said second touchpad sensor, said single touch causing at least one of said first plurality of conductors to coact with at least one of said second plurality of conductors such that the location of the touch can be determined therefrom and further causes at least one of said third plurality of conductors to coact with at least one of said fourth plurality of conductors such that the location of the touch can be determined therefrom.

2. The dual sensor of claim 1 wherein said first touchpad sensor is aligned substantially orthogonally with respect to said second touchpad sensor in plan view.

3. The dual sensor of claim 1 wherein said first touchpad sensor has one fourth the resolution of said second touchpad sensor.

7. The dual sensor of any one of claims 1, 4, or 6 further comprising:

(a) a plurality of drivers in circuit communication with said first plurality of conductors and said third plurality of conductors for placing an electrical signal onto any conductor of said first or third pluralities of conductors, each of said drivers being in circuit communication with one conductor of said first plurality of conductors and each of said drivers being in circuit communication with at least two conductors of said third plurality of conductors;

(b) a plurality of receivers in circuit communication with said second plurality of conductors and said fourth plurality of conductors for detecting an electrical signal on any conductor of said second or fourth pluralities of conductors, each of said receivers being in circuit communication with one conductor of said second plurality of conductors and each of said receivers being in circuit communication with at least two conductors of said fourth plurality of conductors.

8. The dual sensor of any one of claims 1, 4, or 6 further comprising a plurality of drivers in circuit communication with said third plurality of conductors for placing an electrical signal onto any conductor of said third plurality of conductors, each of said drivers being in circuit communication with at least two conductors of said third plurality of conductors.

9. The dual sensor of any one of claims 1, 4, or 6 further comprising a plurality of receivers in circuit communication with said fourth plurality of conductors for detecting an electrical signal on any conductor of said fourth plurality of conductors, each of said receivers being in circuit communication with at least two conductors of said fourth plurality of conductors.

4. A dual sensor comprising:

(a) a first plurality of parallel conductors each spaced from adjacent conductors of said first plurality of parallel conductors by a pair of insulators of a first plurality of insulators;

(b) a second plurality of parallel conductors proximate to said first plurality of conductors, positioned skewed with respect to said first plurality of conductors in plan view, and each spaced from adjacent conductors of said second plurality of parallel conductors by a pair of insulators of a second plurality of insulators;

(c) a third plurality of parallel conductors proximate to said first plurality of conductors and each of said third plurality of conductors spaced from adjacent conductors of said third plurality of parallel conductors by a pair of insulators of a third plurality of insulators; and

(d) a fourth plurality of parallel conductors proximate to said third plurality of conductors, positioned skewed with respect to said third plurality of conductors in plan view, and each spaced from adjacent conductors of said fourth plurality of parallel conductors by a pair of insulators of a fourth plurality of insulators;

(1) wherein said first plurality of conductors are configured to lie substantially in a first plane;

(2) wherein each of said first plurality of insulators extends beyond said first plane toward said second plurality of conductors;

(3) wherein said third plurality of conductors are configured to lie substantially in a second plane; and

(4) wherein each of said third plurality of insulators extends beyond said second plane toward said fourth plurality of conductors.

5. The dual sensor of claim 4 wherein said first plurality of conductors is aligned substantially orthogonally with respect to said second plurality of conductors and said third plurality of conductors is aligned substantially orthogonally with respect to said fourth plurality of conductors in plan view.

10. The dual sensor of any one of claims 4 or 6 wherein said insulators of said first and second pluralities of insulators comprise air and said insulators of said third and fourth pluralities of insulators comprise a different dielectric.

11. The dual sensor of any one of claims 4 or 6 wherein said conductors of said first plurality of conductors comprise copper covered with gold flash and said conductors of said second, third, and fourth pluralities of conductors comprise silver ink.

12. The dual sensor of any one of claims 4 or 6 wherein said conductors and insulators are deposited onto at least three substrates.

6. A dual sensor comprising:

(a) a first plurality of conductors that are flexible, spaced from adjacent conductors by a first plurality of insulators, and substantially parallel to each other;

(b) a second plurality of conductors proximate to said first plurality of conductors, substantially parallel to each other, skewed with respect to said first plurality of conductors in plan view, and spaced from adjacent conductors of said second plurality of conductors by a second plurality of insulators;

(c) a stylus surface proximate to said first plurality of conductors for accepting pressure from a finger, a stylus, or the like;

(d) a third plurality of conductors that are flexible, positioned proximate to said first plurality of conductors, spaced from adjacent conductors by a third plurality of insulators, and substantially parallel to each other; and

(e) a fourth plurality of conductors proximate to said third plurality of conductors, substantially parallel to each other, skewed with respect to said third plurality of conductors in plan view, and spaced from adjacent conductors of said fourth plurality of conductors by a fourth plurality of insulators;

(1) wherein each of said conductors of said first and second pluralities of conductors and each of said insulators of said first and second pluralities of insulators is configured and positioned such that each of said first plurality of conductors has two states;

a relaxed state and a flexed state;

said relaxed state being characterized by said conductor not being in electrically conducting contact with any of said conductors of said second plurality of conductors; and

said flexed state being characterized by said conductor being in electrically conducting contact with at least one conductor of said second plurality of conductors;

(2) wherein each of said conductors of said first and second pluralities of conductors and each of said insulators of said first and second pluralities of insulators is further configured such that the asserting a predetermined amount of pressure from a finger, stylus, or the like to said stylus surface causes at least one of said first plurality of conductors in said relaxed state to enter said flexed state and removing the predetermined amount of pressure from said stylus surface causes said at least one of said conductors in said flexed state to enter said relaxed state;

(3) wherein each of said conductors of said third and fourth pluralities of conductors and each of said insulators of said third and fourth pluralities of insulators is configured and positioned such that each of said third plurality of conductors has two states;

a relaxed state and a flexed state;

said relaxed state being characterized by said conductor not being in electrically conducting contact with any of said conductors of said fourth plurality of conductors; and

said flexed state being characterized by said conductor being in electrically conducting contact with at least one conductor of said fourth plurality of conductors; and

(4) each of said conductors of said third and fourth pluralities of conductors and each of said insulators of said third and fourth pluralities of insulators is further configured such that the asserting a predetermined amount of pressure from a finger, stylus, or the like to said stylus surface causes at least one of said third plurality of conductors in said relaxed state to enter said flexed state and removing the predetermined amount of pressure from said stylus surface causes said at least one of said conductors in said flexed state to enter said relaxed state.

13. A method of fabricating a touchpad sensor comprising the steps of:

(a) affixing a first plurality of conductors onto a first substrate;

(b) affixing a second plurality of conductors onto the first side of a second substrate;

(c) affixing a first plurality of insulators onto the first side of said second substrate;

(d) affixing a third plurality of conductors onto the second side of said second substrate;

(e) affixing a second plurality of insulators onto the second side of said second substrate;

(f) affixing a fourth plurality of conductors onto a third substrate; and

(g) positioning said first, second, and third substrates such that said insulators of said first plurality of insulators are in physical contact with said first plurality of conductors, said insulators of said second plurality of insulators are in physical contact with said fourth plurality of conductors, said insulators of said first plurality of insulators prevent physical contact between said conductors of said first and second pluralities of conductors until a localized pressure is applied, said insulators of said second plurality of insulators prevent physical contact between said conductors of said third and fourth pluralities of conductors until a localized pressure is applied, said first and second pluralities of conductors are skewed in plan view, said third and fourth pluralities of conductors are skewed in plan view.

14. The method of claim 13 wherein said step of affixing said first plurality of conductors onto said first substrate comprises the steps of:

(a) providing a copper-clad substrate; and

(b) etching copper from said substrate leaving longitudinal conductive paths of copper affixed to said substrate.

15. The method of claim 13 wherein said step of affixing said second and third pluralities of conductors onto said second substrate comprises the steps of:

(a) providing a flexible substrate; and

(b) printing conductive paths of a conductive ink onto both sides of said flexible substrate.

16. The method of claim 13 wherein said step of affixing said first and second pluralities of insulators onto said second substrate comprises the steps of:

(a) providing a flexible substrate; and

(b) printing insulating paths of a printable insulating material onto both sides of said flexible substrate.