Touch controller
First Claim
1. A touch controller comprising:
- (a) a touch sensor comprising a position resistor having a definite length wherein the impedance of the position resistor changes in response to touch from a disjunct member;
(b) a current regulator electrically connected to the touch sensor for generating a pressure signal by maintaining a prescribed current through the touch sensor whereby the voltage produced by the current regulator changes as a function of the pressure applied to the touch sensor by the disjunct member; and
(c) a differential amplifier electrically connected to the position resistor for generating a position signal by amplifying the differential voltage across the length of the position resistor whereby the differential voltage across the length of the position resistor changes as a function of the position of the disjunct member on the touch sensor.
2 Assignments
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Accused Products
Abstract
A touch controller is presented that comprises a touch sensor employing a resistive membrane, and an analog electronic circuit that accurately measures the touch position and the touch pressure on the sensor. Several variations of the electronic circuit are presented based on the principle of providing a constant current through the touch sensor, measuring the position with a differential amplifier, and measuring the touch pressure at the output of the current regulator. The touch sensors that may be used include resistive coatings such are used in overlays for computer displays, and force-sensing resistors. The circuits are simple, accurate and low-cost, yet provide measurements of the touch position that are fully decoupled from the pressure measurement, without approximation. The result is that the useful range of touch sensitivity is extended to include very light touches, without sacrificing position accuracy.
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Citations
11 Claims
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1. A touch controller comprising:
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(a) a touch sensor comprising a position resistor having a definite length wherein the impedance of the position resistor changes in response to touch from a disjunct member; (b) a current regulator electrically connected to the touch sensor for generating a pressure signal by maintaining a prescribed current through the touch sensor whereby the voltage produced by the current regulator changes as a function of the pressure applied to the touch sensor by the disjunct member; and (c) a differential amplifier electrically connected to the position resistor for generating a position signal by amplifying the differential voltage across the length of the position resistor whereby the differential voltage across the length of the position resistor changes as a function of the position of the disjunct member on the touch sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification