CAPACITIVE STYLUS FOR A TOUCH SCREEN
First Claim
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1. An apparatus comprising:
- a capacitive sense array comprised of rows and columns of electrodes, configured to detect a presence of a passive touch object and a stylus, wherein the capacitive sense array is configured to receive a signal from the stylus via capacitive coupling; and
a processing device, coupled to the capacitive sense array, configured to receive the signal received by the capacitive sense array, wherein the processing device is further configured to synchronize the capacitive sense array to the stylus based on the signal received by the capacitive sense array.
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Abstract
A system comprising a sensing device and a capacitive sense array configured to track the position of a stylus and synchronize the capacitive sense array to the stylus transmit signal. The system is configured to track the position of both a stylus and a passive touch object. The system is further configured to track the position of the stylus using self capacitance sensing and track the position of the passive touch object using mutual capacitance sensing. The system further configured to modulate the stylus transmit signal to include additional data to support additional stylus functions.
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Citations
20 Claims
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1. An apparatus comprising:
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a capacitive sense array comprised of rows and columns of electrodes, configured to detect a presence of a passive touch object and a stylus, wherein the capacitive sense array is configured to receive a signal from the stylus via capacitive coupling; and a processing device, coupled to the capacitive sense array, configured to receive the signal received by the capacitive sense array, wherein the processing device is further configured to synchronize the capacitive sense array to the stylus based on the signal received by the capacitive sense array. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 17)
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12. A method comprising:
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receiving a transmit signal at a capacitive sense array from a stylus via a capacitive coupling between the capacitive sense array and the stylus; synchronizing the operation of the capacitive sense array to the stylus, wherein the stylus is a timing master, and wherein the capacitive sense array is configured to operate in a first mode for finger position tracking of a touch object and a second mode for stylus position tracking of the stylus; and when synchronized, switching the capacitive sense array between the first mode and the second mode. - View Dependent Claims (13, 14)
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- 15. The method of claim 15, wherein said differentiating further comprises demodulating the transmit signal to extract additional data that is modulated into the transmit signal by at least one of amplitude shift keying, frequency shift keying, binary phase shift modulation, or quadrature phase shift modulation.
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18. A system comprising:
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a capacitive sense array; a stylus, wherein the stylus is configured to provide a transmit signal to the capacitive sense array via capacitive coupling; and a sensing device coupled to the capacitive sense array, wherein the sensing device is configured to receive the transmit signal from the stylus via the capacitive coupling, and to synchronize the operation of the capacitive sense array to the operation of the stylus. - View Dependent Claims (19, 20)
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Specification