Touch sensitive device with stylus support
First Claim
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1. A touch sensitive system comprising:
- a touch panel comprising a transparent capacitive sensing medium including a first set of electrodes and a second set of electrodes;
a touch panel drive unit configured to provide a drive signal to electrodes that comprise the first set of electrodes and that comprise second set of electrodes in the touch panel;
a stylus electrode;
a stylus sense unit having a differentiation circuit coupled to the stylus electrode, the stylus sense unit configured to generate stylus response signals from signals received by the stylus electrode, the stylus response signals comprising an output signal from the differentiation circuit, the output signal being substantially a derivative with respect to time of an input signal received by the differentiation circuit, the amplitude of the stylus response signals being responsive to the coupling capacitance between the stylus electrode and one of the plurality of drive electrodes;
a stylus measurement unit communicatively coupled to the stylus sense unit and configured to measure the amplitude of the stylus response signals; and
a touch panel controller configured to receive information indicative of the measurements and to determine therefrom the position the stylus, if present, on the touch surface.
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Abstract
A touch-sensitive device with stylus includes a touch panel, a touch panel drive unit, a stylus sense unit, and a measurement unit. A touch by a stylus proximate to a touch panel electrode changes a capacitive coupling between the touch panel electrode and a stylus electrode. The amplitude of the response signal is responsive to the capacitive coupling between the touch panel electrode and the stylus electrode, and is measured to provide an indication of the position of the stylus electrode relative to the touch panel.
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Citations
19 Claims
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1. A touch sensitive system comprising:
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a touch panel comprising a transparent capacitive sensing medium including a first set of electrodes and a second set of electrodes; a touch panel drive unit configured to provide a drive signal to electrodes that comprise the first set of electrodes and that comprise second set of electrodes in the touch panel; a stylus electrode; a stylus sense unit having a differentiation circuit coupled to the stylus electrode, the stylus sense unit configured to generate stylus response signals from signals received by the stylus electrode, the stylus response signals comprising an output signal from the differentiation circuit, the output signal being substantially a derivative with respect to time of an input signal received by the differentiation circuit, the amplitude of the stylus response signals being responsive to the coupling capacitance between the stylus electrode and one of the plurality of drive electrodes; a stylus measurement unit communicatively coupled to the stylus sense unit and configured to measure the amplitude of the stylus response signals; and a touch panel controller configured to receive information indicative of the measurements and to determine therefrom the position the stylus, if present, on the touch surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification