Methods and apparatus for data input

• US 5,861,875 A
• Filed: 12/11/1996
• Issued: 01/19/1999
• Est. Priority Date: 07/13/1992
• Status: Expired due to Term

• Current Assignee: Cirque Corporation
• Sponsoring Entity: Cirque Corporation
• Inventors: Gerpheide, George E.
• Primary Examiner(s): Hjerpe, Richard A.
• Assistant Examiner(s): FATAHI YAR, MAHMOUD
• Time in USPTO: 769 Days
• Field of Search: 345/168, 345/173, 345/174, 345/179, 341/20, 341/23, 178/18.06, 178/19.03
• US Class Current: 345/174
• CPC Class Codes: G06F 3/041 : Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/044 : by capacitive means

Abstract

Methods and apparatus for data input. Devices are provided in accordance with this invention which utilize capacitive coupling of an object to the device to sense the object'"'"'s position. The devices are comprised of a plurality of electrode strips which form virtual electrodes. The virtual electrodes are selectively connected to form virtual dipole electrodes which are responsive to the object'"'"'s position.

Claims

1. Apparatus for determining position of a conductive passive object such as a person'"'"'s finger, hand, or conductive object held in the person'"'"'s hand comprising

at least one first electrode strip,

at least one second electrode strip disposed adjacent to the first electrode strip to cross thereover and define a cross-over region,

means for supplying electrical charges to the at least one first electrode strip and the at least one second electrode strip, to thereby develop electric fields such that a mutual capacitance is present therebetween, said mutual capacitance decreasing when the object is positioned in proximity to the cross-over region, the degree of such decrease depending upon the relative position of the passive object to the cross-over region,

means for measuring the decrease in mutual capacitances between the strips, and

means responsive to said measuring means for determining the position of the object relative to the cross-over region.

2. Apparatus as in claim 1 wherein the electrode strips are elongate and substantially longer than the length or width of the cross-over region.

3. Apparatus as in claim 2 further comprising

a plurality of spaced-apart second electrode strips disposed adjacent to the first electrode strip to cross thereover and define a plurality of cross-over regions, such that mutual capacitances are present between the first electrode strip and each of the second electrode strips,

means for measuring the decrease in mutual capacitances between the first electrode strip and each of the second electrode strips, and

means responsive to said measuring means for determining the position of the object relative to the cross-over regions.

4. Apparatus as in claim 3 wherein the second electrode strips are arranged generally parallel with one another, and generally at right angles with the first electrode strip.

5. Apparatus as in claim 3 further comprising

a plurality of spaced-apart first electrode strips disposed adjacent to the second electrode strips to cross thereunder and define a cross-over region at each location where one of the second electrode strips crosses over one of the first electrode strips, such that mutual capacitances are present between each of the first electrode strips and each of the second electrode strips,

means for measuring the decrease in mutual capacitances between the first electrode strips and the second electrode strips, and

means responsive to said measuring means for determining the position of the object relative to the cross-over regions.

6. Apparatus as in claim 5 wherein the first electrode strips are arranged generally parallel with one another, wherein the second electrode strips are arranged generally parallel with one another, and wherein the second electrode strips cross over the first electrode strips generally at right angles.

7. Apparatus as in claim 5 further including insulator means disposed between the first electrode strips and the second electrode strips.

8. Apparatus as in claim 5 further including

control means operatively coupled to the synthesis means for supplying control signals to the synthesis means to thereby specify which of the first electrode strips and second electrode strips are to constitute the positive halves and negative halves.

9. Apparatus as in claim 8 wherein said position determining means comprises

balance ratio measuring means for determining electrical balance ratios from the mutual capacitances among the virtual dipole electrode halves, and

means for determining the position of the passive object from the balance ratios.

10. Apparatus for determining the position of a conductive passive object such as a person'"'"'s finger or hand or conductive object held in the person'"'"'s hand comprising

pad means for sensing the object'"'"'s position, the pad means including

a plurality of first electrode strips spaced apart in a first array

one or more second electrode strips disposed to cross over the first electrode strips to define overlapping regions on the first electrode strips by the second electrode strip,

wherein mutual capacitances are developed between the first electrode strips and second electrode strip,

wherein the object perturbs the mutual capacitances when the object comes in proximity to the pad means, thereby decreasing the mutual capacitances, and

measurement means operatively coupled to the pad means for measuring the decrease in mutual capacitances in the pad means to thereby determine the position of the object relative to the pad means.

11. Apparatus as in claim 10 wherein said measurement means includes

synthesis means responsive to control signals for selecting first electrode strips and the second electrode strip, between which electric fields are to be developed in the course of measuring mutual capacitance decreases,

control means for supplying control signals to the synthesis means to designate the selected first electrode strips, and

means for measuring the charge supplied to the strips to thereby measure the mutual capacitances in the pad means and this determine the location of the object.

12. Apparatus as in claim 11 wherein the pad means further comprises

insulator means having first and second sides electrically interfaced with the plurality of first electrode strips on the first side for providing an insulating substrate for the pad means, and

said second electrode strip being interfaced with the insulator means on the second side.

13. Apparatus as in claim 12 wherein said pad means further comprises a plurality of second electrode strips spaced apart in a second array to extend at an angle to the direction in which the first electrode strips extend so that each electrode strip in the second array crosses over each electrode strip in the first array to define a plurality of overlapping regions of the first electrode strips by the second electrode strips, wherein the synthesis means includes means responsive to control signals for selecting second electrode strips and first electrode strips between which electric fields are to be developed in the course of measuring mutual capacitance decreases, wherein the control means includes means for supplying control signals to the synthesis means to designate the selected second electrode strips, and first electrode strips, and wherein the charge supplying means includes means for supplying electrical charges to selected electrode strips in the first array and second array to thereby establish electric fields between the selected electrode strips of the first array and the selected electrode strips of the second array at the overlapping regions.

14. Apparatus as in claim 13 wherein said charge supplying means further includes means for supplying electrical charges to selected pairs of electrode strips in the first array to thereby form selected virtual dipole electrodes in the first array, and to selected pairs of electrode strips in the second array to thereby form selected virtual dipole electrodes in the second array, each virtual dipole electrode having a positive half electrode strip and a negative half electrode strip such that electric fields are established between selected halves of each polarity in the first array, and selected halves of each polarity in the second array.