CONTROL CIRCUIT AND CONTROL METHOD FOR TOUCH PANEL
First Claim
1. A control method, for a touch panel comprising a first terminal, a second terminal, a third terminal, a first resistive film arranged such that one edge thereof is connected to the first terminal and an edge that is opposite to the aforementioned one edge is connected to the second terminal, and a second resistive film arranged with a gap between it and the first resistive film such that one edge thereof is connected to the third terminal, the control method comprising:
- applying a predetermined first bias voltage and a predetermined second bias voltage to the first and second terminals, respectively;
detecting a panel voltage that occurs at the third terminal;
detecting a panel current that flows through a path including the first terminal, the first resistive film, and the second terminal; and
determining coordinates touched by a user, based upon the panel voltage and the panel current.
1 Assignment
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Accused Products
Abstract
A first resistive film is arranged such that one edge thereof is connected to a first terminal, and an edge that is opposite to the aforementioned edge is connected to a second terminal. A second resistive film is arranged with a gap between it and the first resistive film such that one edge thereof is connected to a third terminal. A voltage generating unit applies a predetermined first bias voltage and a predetermined second bias voltage to the first terminal and the second terminal, respectively. A voltage detection unit detects a panel voltage that occurs at the third terminal. A current detection unit detects a panel current that flows through a path including the first terminal, the first resistive film, and the second terminal. A computation unit determines the coordinates touched by the user, based upon the values of the panel voltage and the panel current.
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Citations
36 Claims
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1. A control method, for a touch panel comprising a first terminal, a second terminal, a third terminal, a first resistive film arranged such that one edge thereof is connected to the first terminal and an edge that is opposite to the aforementioned one edge is connected to the second terminal, and a second resistive film arranged with a gap between it and the first resistive film such that one edge thereof is connected to the third terminal, the control method comprising:
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applying a predetermined first bias voltage and a predetermined second bias voltage to the first and second terminals, respectively; detecting a panel voltage that occurs at the third terminal; detecting a panel current that flows through a path including the first terminal, the first resistive film, and the second terminal; and determining coordinates touched by a user, based upon the panel voltage and the panel current. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A control circuit configured to control a touch panel comprising a first terminal, a second terminal, a third terminal, a first resistive film arranged such that one edge thereof is connected to the first terminal and an edge that is opposite to the aforementioned one edge is connected to the second terminal, and a second resistive film arranged with a gap between it and the first resistive film such that one edge thereof is connected to the third terminal, the control circuit comprising:
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a voltage generating unit configured to apply a predetermined first bias voltage and a predetermined second bias voltage to the first and second terminals, respectively; a voltage detection unit configured to detect a panel voltage that occurs at the third terminal; a current detection unit configured to detect a panel current that flows through a path including the first terminal, the first resistive film, and the second terminal; and a coordinate determination unit configured to determine the coordinates touched by the user, based upon the panel voltage and the panel current thus detected. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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15. A control circuit configured to control a touch panel comprising a first terminal, a second terminal, a third terminal, a first resistive film arranged such that one edge thereof is connected to the first terminal and an edge that is opposite to the aforementioned one edge is connected to the second terminal, and a second resistive film arranged with a gap between it and the first resistive film such that one edge thereof is connected to the third terminal, the control circuit comprising:
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a voltage generating unit configured to apply a predetermined first bias voltage and a predetermined second bias voltage to the first and second terminals, respectively; a voltage detection unit configured to detect a panel voltage that occurs at the third terminal; a current detection unit configured to detect a panel current that flows through a path including the first terminal, the first resistive film, and the second terminal; and a coordinate determination unit configured to determine the coordinates touched by the user, based upon the panel voltage and the panel current thus detected, and wherein the voltage generating unit comprises a regulator which includes an output transistor provided as an extension to a path on the first terminal side that includes the first terminal, the first resistive film, and the second terminal, and which is configured to apply the first bias voltage to the first terminal, and wherein the current detection unit comprises a detection transistor connected to the output transistor in a current mirror manner, and a detection resistor arranged on a path of the detection transistor, and wherein the current detection unit is configured to output a value that corresponds to a voltage drop that occurs at the detection resistor as a value which represents the panel current. - View Dependent Claims (20, 21, 22, 23, 24, 25)
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16. A control circuit configured to control a touch panel comprising a first terminal, a second terminal, a third terminal, a fourth terminal, a first resistive film arranged such that one edge thereof is connected to the first terminal and an edge that is opposite to the aforementioned one edge is connected to the second terminal, and a second resistive film arranged with a gap between it and the first resistive film such that one edge thereof is connected to the third terminal and an edge that is opposite to the aforementioned one edge is connected to the fourth terminal, the control circuit comprising:
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a voltage generating unit configured to apply a predetermined first bias voltage and a predetermined second bias voltage to respectively the first and second terminals and set the third and fourth terminals to a high-impedance state in a first state, and to apply a predetermined first bias voltage and a predetermined second bias voltage to respectively the third and fourth terminals and set to the first and second terminals to a high-impedance state in a second state; a voltage detection unit configured to detect a panel voltage that occurs at one of the third and fourth terminals in the first state, and to detect a panel voltage that occurs at one of the first and second terminals in the second state; a current detection unit configured to detect, in the first state, a panel current that flows through a path including the first terminal, the first resistive film, and the second terminal, and to detect, in the second state, a panel current that flows through a path including the third terminal, the second resistive film, and the fourth terminal; and a coordinate determination unit configured to determine coordinates touched by the user, based upon the values of the panel voltage and the panel current thus detected, and wherein the voltage generating unit comprises a regulator which includes an output transistor, and which is configured to generate the first bias voltage, and a selector which is arranged such that the first bias voltage is received via an input terminal thereof, a first output terminal thereof is connected to the first terminal, and a second output terminal thereof is connected to the third terminal, and which is configured such that the first output terminal side is on in the first state, and the second output terminal side is on in the second state, and wherein the current detection unit comprises a detection transistor connected to the output transistor in a current mirror manner, and a detection resistor arranged on a path of the detection transistor, and wherein the current detection unit is configured to output a value that corresponds to a voltage drop that occurs at the detection resistor as a value which represents the panel current. - View Dependent Claims (18, 19, 29, 31, 33, 34)
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17. A control circuit configured to control a touch panel comprising a first terminal, a second terminal, a third terminal, a fourth terminal, a first resistive film arranged such that one edge thereof is connected to the first terminal and an edge that is opposite to the aforementioned one edge is connected to the second terminal, and a second resistive film arranged with a gap between it and the first resistive film such that one edge thereof is connected to the third terminal and an edge that is opposite to the aforementioned one edge is connected to the fourth terminal, the control circuit comprising:
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a voltage generating unit configured to apply a predetermined first bias voltage and a predetermined second bias voltage to respectively the first and second terminals and to set the third and fourth terminals to a high-impedance state in a first state, and to apply a predetermined first bias voltage and a predetermined second bias voltage to respectively the third and fourth terminals and to set the first and second terminals to a high-impedance state, a voltage detection unit configured to detect each of the panel voltages that respectively occur at the third and fourth terminals in the first state, and to detect each of the panel voltages that respectively occur at the first and second terminals in the second state; a current detection unit configured to detect, in the first state, a panel current that flows through a path including the first terminal, the first resistive film, and the second terminal, and to detect, in the second state, a panel current that flows through a path including the third terminal, the second resistive film, and the fourth terminal; and a coordinate determination unit configured to determine coordinates touched by the user, based upon the panel voltage and the panel current thus detected, and wherein the voltage generating unit comprises a regulator which includes an output transistor, and which is configured to generate the first bias voltage, and a selector which is arranged such that the first bias voltage is received via an input terminal thereof, a first output terminal thereof is connected to the first terminal, and a second output terminal thereof is connected to the third terminal, and which is configured such that the first output terminal side is on in the first state, and the second output terminal side is on in the second state, and wherein the current detection unit comprises a detection transistor connected to the output transistor in a current mirror manner, and a detection resistor arranged on a path of the detection transistor, and wherein the current detection unit is configured to output a value that corresponds to a voltage drop that occurs at the detection resistor as a value which represents the panel current. - View Dependent Claims (27, 28, 30, 32, 35, 36)
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26. A control method for a touch panel comprising a first terminal, a second terminal, a third terminal, a first resistive film arranged such that one edge thereof is connected to the first terminal and an edge that is opposite to the aforementioned one edge is connected to the second terminal, and a second resistive film arranged with a gap between it and the first resistive film such that one edge thereof is connected to the third terminal, the control method comprising:
- applying a predetermined first bias voltage and a predetermined second bias voltage to the first and second terminals using a regulator which includes an output transistor provided as an extension to a path on the first terminal side including the first terminal, the first resistive film, and the second terminal, and which is configured to apply the first bias voltage to the first terminal;
detecting a panel voltage that occurs at the third terminal; detecting a value that corresponds to a voltage drop that occurs at the detection resistor as a panel current that flows through a path including the first terminal, the first resistive film, and the second terminal, using a detection transistor connected to the output transistor in a current mirror manner and a detection resistor arranged on a path of the detection transistor; and determining coordinates touched by the user, based upon the panel voltage and the panel current.
- applying a predetermined first bias voltage and a predetermined second bias voltage to the first and second terminals using a regulator which includes an output transistor provided as an extension to a path on the first terminal side including the first terminal, the first resistive film, and the second terminal, and which is configured to apply the first bias voltage to the first terminal;
Specification