Position detecting device and position detecting method
First Claim
1. A position detecting device defining a position detecting area, for use with a position indicator, to detect a position indicated by the position indicator on the position detecting area, comprising:
- an excitation coil arranged to surround a periphery of the position detecting area to supply an excitation signal to the position indicator;
a sensor configured to detect a signal transmitted from the position indicator based on the excitation signal supplied to the position indicator from the excitation coil, to thereby detect a position indicated by the position indicator on the position detecting area; and
a controller configured to control a signal level of the excitation signal supplied from the excitation coil to the position indicator based on the detected position indicated by the position indicator.
1 Assignment
0 Petitions
Accused Products
Abstract
An excitation coil (19) surrounding the periphery of the position detecting area is connected to an oscillating circuit (21), which oscillates at a frequency f0, through a drive circuit (20). A CPU (18) supplies control signals to a selecting circuit (12), a sample-and-hold circuit (16), an A/D conversion circuit (17), and the drive circuit (20). Based on the control signal output from the CPU (18), the drive circuit (20) controls the power of the signal output from the excitation coil (19) to ON or OFF. Further, the strength of the excitation signal supplied from the excitation coil (19) is controlled based on information obtained by analyzing a signal received from a position indicator (40), such as the position indicated by the position indicator on the position detecting area and/or a strength of the signal received from the position indicator.
52 Citations
21 Claims
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1. A position detecting device defining a position detecting area, for use with a position indicator, to detect a position indicated by the position indicator on the position detecting area, comprising:
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an excitation coil arranged to surround a periphery of the position detecting area to supply an excitation signal to the position indicator; a sensor configured to detect a signal transmitted from the position indicator based on the excitation signal supplied to the position indicator from the excitation coil, to thereby detect a position indicated by the position indicator on the position detecting area; and a controller configured to control a signal level of the excitation signal supplied from the excitation coil to the position indicator based on the detected position indicated by the position indicator. - View Dependent Claims (2, 3, 17, 18, 19, 20, 21)
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4. A position detecting device defining a position detecting area, for use with a position indicator, to detect a position indicated by the position indicator on the position detecting area, comprising:
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a sensor configured to be arranged on a front surface of a liquid crystal display device to detect a signal transmitted from the position indicator to thereby detect a position indicated by the position indicator on the position detecting area, which is defined relative to the liquid crystal display device; an excitation coil arranged to surround a periphery of the position detecting area to supply driving power to circuitry of the position indicator; and a controller configured to dynamically control a power level of a signal supplied to the excitation coil based on the detected position indicated by the position indicator. - View Dependent Claims (5, 6, 7, 8, 9)
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10. A method of controlling power usage in a device that includes a position detecting device for detecting a position indicated by a position indicator on a position detecting area of the position detecting device, comprising:
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supplying an excitation signal to the position indicator with an excitation coil provided to surround a periphery of the position detecting area of the position detecting device; detecting, in the position detecting area, an AC signal transmitted from the position indicator based on the excitation signal supplied from the excitation coil; detecting a position indicated by the position indicator on the position detecting area based on the detected AC signal transmitted from the position indicator; and controlling a strength of the excitation signal supplied from the excitation coil, based on the detected position indicated by the position indicator. - View Dependent Claims (11, 12)
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13. A position detecting method for detecting a position indicated by a position indicator on a position detecting area of a position detecting device, comprising:
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detecting the position indicated by the position indicator on the position detecting area of the position detecting device with a sensor arranged on a front surface of a liquid crystal display device, the position detecting area being defined relative to the liquid crystal display device; supplying driving power to circuitry provided in the position indicator with an excitation coil that surrounds a periphery of the position detecting area of the position detecting device; and dynamically controlling a power level of a signal supplied to the excitation coil based on the detected position indicated by the position indicator on the position detecting area. - View Dependent Claims (14, 15, 16)
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Specification