Stylus and stylus circuitry for capacitive touch screens
First Claim
1. A circuit for a capacitive touch screen stylus, the circuit comprising:
- a. a conductive tip for providing capacitive coupling with a capacitive touch screen;
b. an inverting charge integrator connected to the conductive tip for providing an output signal proportional to a charge induced at the conductive tip;
c. an inverting amplifier for generating an amplified signal proportional to the signal output from the inverting charge integrator;
d. a conductive contact for providing electrical or capacitive coupling between the amplified signal and an exterior of the stylus; and
e. a power supply circuit for powering the inverting charge integrator and the inverting amplifier.
2 Assignments
0 Petitions
Accused Products
Abstract
A stylus for a capacitive touch screen includes an inverting charge integrator circuit is connected to a conductive tip for providing an output signal proportional to a charge induced at the conductive tip. An inverting amplifier generates an amplified signal proportional to the signal output from the inverting charge integrator. A conductive contact provides electrical or capacitive coupling between the amplified signal and an exterior of the stylus which may provide electrical or capacitive coupling with a person holding the stylus. In other embodiments, the order of the inverting charge integrator and the inverting amplifier may be reversed. A power supply circuit powers the inverting charge integrator and the inverting amplifier. Shielding may be implemented to isolate the stylus circuitry and prevent oscillation. The provided circuitry may enable a ball point or other fine point stylus tip configurations.
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Citations
36 Claims
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1. A circuit for a capacitive touch screen stylus, the circuit comprising:
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a. a conductive tip for providing capacitive coupling with a capacitive touch screen; b. an inverting charge integrator connected to the conductive tip for providing an output signal proportional to a charge induced at the conductive tip; c. an inverting amplifier for generating an amplified signal proportional to the signal output from the inverting charge integrator; d. a conductive contact for providing electrical or capacitive coupling between the amplified signal and an exterior of the stylus; and e. a power supply circuit for powering the inverting charge integrator and the inverting amplifier. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A circuit for a capacitive touch screen stylus, the circuit comprising:
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a. a conductive tip for providing capacitive coupling with a capacitive touch screen; b. an inverting transimpedance amplifier connected to the conductive tip for generating an output signal proportional to a current induced at the conductive tip; c. an inverting integrator for providing an output voltage proportional to an integrated output signal of the inverting transimpedance amplifier; d. a conductive contact for providing electrical or capacitive coupling between the output voltage from the inverting integrator to an exterior portion of the stylus; and e. a power supply circuit for powering the inverting transimpedance amplifier first and the inverting integrator. - View Dependent Claims (24, 25)
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26. A stylus for a capacitive touch screen, the stylus comprising:
a. an elongated barrel for enclosing a stylus circuit comprising; i. an integrator circuit connected to a conductive tip of the stylus for generating an output signal proportional to a charge induced at the conductive tip; ii. an amplifier circuit for providing an output voltage proportional to the output signal from the integrator circuit; and iii. a conductive contact for providing electrical or capacitive coupling between the output voltage from the amplifier circuit and a surface of the stylus. - View Dependent Claims (27, 28)
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29. A stylus for a capacitive touch screen, the stylus comprising:
a. an elongated barrel for enclosing a stylus circuit comprising; i. an amplifier circuit for providing an output signal proportional to the current induced at a conductive tip of the stylus; ii. an integrator circuit for generating an output voltage proportional to the output signal from the amplifier circuit; and iii. a conductive contact for providing electrical or capacitive coupling between the output voltage from the integrator circuit and a surface of the stylus. - View Dependent Claims (30, 31)
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32. A capacitive touch screen stylus comprising:
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a. an amplifier circuit for providing an output signal proportional to the current induced at a conductive tip of the stylus; b. an integrator circuit for generating an output voltage proportional to the output signal from the amplifier circuit; and c. a conductive contact for providing electrical or capacitive coupling between the output voltage from the integrator circuit and a surface of the stylus. - View Dependent Claims (33, 34)
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35. A method for charging a tip of a stylus for a capacitive touch screen, the method comprising:
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a. determining an amount of charge induced at a stylus tip by a positive or negative going drive line transition in a capacitive touch screen; and b. outputting to an exterior of the stylus a positive or negative going voltage change that is proportional to the determined amount of charge wherein a positive going drive line transition results in a positive going output voltage change, and a negative going drive line transition results in a negative going output voltage change.
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36. A stylus for a capacitive touch screen comprising:
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a. circuitry for determining an amount of charge induced at a stylus tip by a positive or negative going drive line transition in a capacitive touch screen; and b. circuitry for outputting to an exterior of the stylus a positive or negative going voltage change that is proportional to the determined amount of charge wherein a positive going drive line transition results in a positive going output voltage change, and a negative going drive line transition results in a negative going output voltage change.
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Specification