Method and system for measuring position on surface capacitance touch panel using a flying capacitor
First Claim
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1. A method for measuring the position of a pointing object on a surface capacitance touch panel, said method comprising the steps of:
- 1) providing a touch panel comprised of an insulating substrate, a resistive material disposed on the substrate, and a dielectric disposed on the resistive material;
2) connecting a capacitor to opposite first and second edges of the touch panel and measuring current X1 across the surface thereof;
3) switching connections of the capacitor between the first and second edges of the touch panel and measuring current X2 across the surface thereof;
4) connecting the capacitor to opposite third and fourth edges of the touch panel and measuring current X3 across the surface thereof;
5) switching connections of the capacitor between the third and fourth edges of the touch panel and measuring current X4 across the surface thereof; and
6) triangulating a position of the pointing object using a current measurement circuit to obtain the current measurements X1, X2, X3 and X4.
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Abstract
A touch panel having a substantially even coating of a conductive material on a non-conductive substrate and then covering the conductive material with a dielectric material, wherein a novel current measuring circuit reduces the effect of stray capacitance on the accuracy of a current measurement so that the relative X and Y position of an object on the touch panel can be determined using simple ratio equations.
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Citations
13 Claims
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1. A method for measuring the position of a pointing object on a surface capacitance touch panel, said method comprising the steps of:
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1) providing a touch panel comprised of an insulating substrate, a resistive material disposed on the substrate, and a dielectric disposed on the resistive material; 2) connecting a capacitor to opposite first and second edges of the touch panel and measuring current X1 across the surface thereof; 3) switching connections of the capacitor between the first and second edges of the touch panel and measuring current X2 across the surface thereof; 4) connecting the capacitor to opposite third and fourth edges of the touch panel and measuring current X3 across the surface thereof; 5) switching connections of the capacitor between the third and fourth edges of the touch panel and measuring current X4 across the surface thereof; and 6) triangulating a position of the pointing object using a current measurement circuit to obtain the current measurements X1, X2, X3 and X4. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification