System and method for determining touch positions based on position-dependent electrical charges
First Claim
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1. An apparatus for determining the position of a touching implement on the sensing surface of a device, comprising:
- a signal generation circuit, including four circuit paths arranged relative to different positions on the sensing surface and configured to be synchronously operated, to create a position-dependent electrical charge on a touching implement that has engaged an area on the sensing surface of the device; and
a signal processing circuit, responsive to the position-dependent electrical charge, to locate the area on the sensing surface of the device by respective measurements relative to four different values from the four circuit paths, the signal processing circuit and the four circuit paths being configured and arranged to compute the position of the touching implement on the sensing surface.
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Abstract
Systems and methods determine the position of a touch on a surface of a device, such as a touch-sensitive device, by using position-dependent electrical charges. In such a method, the position of a touching implement is determined on the sensing surface of a device. The method includes generating signals on the surface of the device to create a position-dependent electrical charge on the touching implement; and measuring the position-dependent electrical charge to indicate a coordinate on the sensing surface for establishing the position of the touching implement.
71 Citations
25 Claims
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1. An apparatus for determining the position of a touching implement on the sensing surface of a device, comprising:
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a signal generation circuit, including four circuit paths arranged relative to different positions on the sensing surface and configured to be synchronously operated, to create a position-dependent electrical charge on a touching implement that has engaged an area on the sensing surface of the device; and a signal processing circuit, responsive to the position-dependent electrical charge, to locate the area on the sensing surface of the device by respective measurements relative to four different values from the four circuit paths, the signal processing circuit and the four circuit paths being configured and arranged to compute the position of the touching implement on the sensing surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for determining the position of a touching implement on the sensing surface of a device, comprising:
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a signal drive circuit, coupled to the surface of the device, including four circuit paths arranged relative to different positions on the sensing surface and configured to be synchronously operated, to generate signals on the surface for creating a position-dependent electrical charge on the touching implement; and a charge measurement circuit, coupled to the surface of the device, to measure the position-dependent electrical charge for indicating a coordinate on the sensing surface for establishing the position of the touching implement, by respective measurements relative to four different values from the four circuit paths, the charge measurement circuit and the four circuit paths being configured and arranged to compute the position of the touching implement on the sensing surface. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method for determining the position of a touching implement on the sensing surface of a device, comprising:
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generating signals on the surface of the device, using four circuit paths arranged relative to different positions on the sensing surface, to create a position-dependent electrical charge on the touching implement; and measuring the position-dependent electrical charge via different values from the four circuit paths, to indicate a coordinate on the sensing surface for establishing the position of the touching implement.
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21. A method for determining the position of a touching implement on a sensing surface of a touch-sensitive device, the method comprising:
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(a.) during a first time period, connecting two adjacent corners of the sensing surface to a reference voltage while maintaining the two opposite corners in a floating state disconnected from any voltage source, the first time period being sufficient to raise the potential of the sensing surface edge between the two adjacent corners to a level at or near the reference voltage while the potential of the sensing surface edge between the two opposite corners remains at a level lower than the reference voltage commensurate with an R-C time constant delay across the sensing surface; and (b) at the end of the first time period, disconnecting the two adjacent corners from the reference voltage, and connecting the sensing surface to an integrator capacitor for a second time period sufficient for the integrator capacitor to accumulate the charge from the sensing surface; (c) repeating steps (a) and (b) to accumulate sufficient charge in the integrator capacitor for measurement, and in response thereto measuring the charge stored in the integrator capacitor. - View Dependent Claims (22, 23, 24, 25)
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Specification