Position detecting device
First Claim
1. A position detecting device including a sensor having an electrode pattern formed of a plurality of first electrodes arranged in a first direction and a plurality of second electrodes arranged in a second direction intersecting with the first direction, the position detecting device supplying a drive signal to the first electrodes and detecting a position of an indicator on the electrode pattern from a reception signal obtained from the second electrodes, the position detecting device comprising:
- a first selection circuit configured to select two sets of the second electrodes, which are separate from each other by a distance equivalent to a second predetermined number of electrodes, from the plurality of second electrodes;
a second selection circuit configured to select two sets of the first electrodes, which are separate from each other by a distance equivalent to a first predetermined number of electrodes, from the plurality of first electrodes;
a drive signal supply circuit configured to supply the drive signal to each of the two sets of the first electrodes selected by the second selection circuit by outputting two signals having phases inverted from each other;
a differential amplifier circuit having a non-inverting input terminal, to which one set of the two sets of the second electrodes selected by the first selection circuit is connected, and an inverting input terminal, to which the other set of the two sets of the second electrodes is connected;
a detection circuit configured to detect the position of the indicator on the electrode pattern from an output signal of the differential amplifier circuit; and
a control circuit that controls selection by the first and second selection circuits by determining the first and second predetermined numbers in such a manner that, when positions of plural indicators are detected by the detection circuit, only one intersection among four intersections, which are respectively formed by the two sets each of electrodes selected by the first and second selection circuits, is near the position of one of the plural indicators and the three other intersections are not near any of the plural indicators.
1 Assignment
0 Petitions
Accused Products
Abstract
A position detecting device is provided, which is capable of stably detecting an indicator with less susceptibility to the influence of noise by using a differential amplifier circuit and multi-touch. The device includes a sensor having an electrode pattern formed of plural first electrodes arranged in a first direction and plural second electrodes arranged in a second direction. The device selects two sets of the first electrodes separate from each other by a distance equivalent to a predetermined number of electrodes and supplies two drive signals having phases inverted from each other. The device selects two sets of the second electrodes separate from each other by a distance equivalent to a predetermined number of electrodes and connects the selected second electrodes to two differential inputs of a differential amplifier circuit. The device controls selection of two sets of the first electrodes and two sets of the second electrodes.
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Citations
11 Claims
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1. A position detecting device including a sensor having an electrode pattern formed of a plurality of first electrodes arranged in a first direction and a plurality of second electrodes arranged in a second direction intersecting with the first direction, the position detecting device supplying a drive signal to the first electrodes and detecting a position of an indicator on the electrode pattern from a reception signal obtained from the second electrodes, the position detecting device comprising:
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a first selection circuit configured to select two sets of the second electrodes, which are separate from each other by a distance equivalent to a second predetermined number of electrodes, from the plurality of second electrodes; a second selection circuit configured to select two sets of the first electrodes, which are separate from each other by a distance equivalent to a first predetermined number of electrodes, from the plurality of first electrodes; a drive signal supply circuit configured to supply the drive signal to each of the two sets of the first electrodes selected by the second selection circuit by outputting two signals having phases inverted from each other; a differential amplifier circuit having a non-inverting input terminal, to which one set of the two sets of the second electrodes selected by the first selection circuit is connected, and an inverting input terminal, to which the other set of the two sets of the second electrodes is connected; a detection circuit configured to detect the position of the indicator on the electrode pattern from an output signal of the differential amplifier circuit; and a control circuit that controls selection by the first and second selection circuits by determining the first and second predetermined numbers in such a manner that, when positions of plural indicators are detected by the detection circuit, only one intersection among four intersections, which are respectively formed by the two sets each of electrodes selected by the first and second selection circuits, is near the position of one of the plural indicators and the three other intersections are not near any of the plural indicators. - View Dependent Claims (2, 3, 4)
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5. A position detecting device including a sensor having a lattice-shaped electrode pattern formed of a plurality of first electrodes arranged in a first direction and a plurality of second electrodes arranged in a second direction intersecting with the first direction, the position detecting device supplying a transmission signal to the first electrodes and detecting a position of a first indicator on the electrode pattern from a reception signal obtained from the plurality of second electrodes, the position detecting device comprising:
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a drive signal supply circuit configured to supply a predetermined drive signal to the first electrodes; a first selection circuit configured to select two sets of the second electrodes, which are separate from each other by a distance equivalent to a predetermined number of electrodes, from the plurality of second electrodes; a second selection circuit configured to select the first electrode, to which the drive signal is supplied; a differential amplifier circuit having a non-inverting input terminal, to which one set of the two sets of the second electrodes is connected, and an inverting input terminal, to which the other set is connected; a detection circuit configured to detect the position of the first indicator on the electrode pattern from an output signal of the differential amplifier circuit; and a control circuit that carries out, for the first selection circuit, first selection control to select the two sets of the second electrodes in such a manner that, when positions of plural indicators including the first indicator are detected by the detection circuit and when a signal from the second electrode at the detected position of the first indicator is supplied to one terminal of the non-inverting input terminal and the inverting input terminal of the differential amplifier circuit, a signal from the second electrode where none of the plural indicators is at is supplied to the other terminal of the differential amplifier circuit. - View Dependent Claims (6, 7, 8, 9, 10, 11)
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Specification