Position detecting apparatus and method for detecting position pointing device
First Claim
1. A position detecting apparatus for detecting a position indicated by a first position pointing device using electromagnetic induction between the first position pointing device and a tablet;
- the first position pointing device comprising;
a resonance circuit having at least two selectable resonance frequencies;
means for selecting one of the at least two resonance frequencies; and
means for receiving frequency selecting information for the frequency selecting means; and
the tablet comprising;
means for transmitting the frequency selecting information to the receiving means to set an initial resonance frequency in the resonance circuit of the first position pointing device;
means for detecting the first position pointing device having the initial resonance frequency;
means for selectively changing the resonance frequency of the first position pointing device to a second resonance frequency;
means for detecting an additional position pointing device by transmitting a signal equal to the initial resonance frequency; and
means for detecting the first position pointing device using the second resonance frequency.
1 Assignment
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Accused Products
Abstract
A position detecting apparatus capable of detecting position pointing devices of any combination simultaneously out of plural position pointing devices, thereby providing a user a friendly apparatus. A frequency of a resonance circuit provided inside a position pointing device is set by a command signal transmitted from a tablet, causing plural position pointing devices placed on the tablet to have a different frequencies, thereby suppressing electromagnetic interference among position pointing devices on the tablet, so that a simultaneous detection becomes available.
137 Citations
33 Claims
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1. A position detecting apparatus for detecting a position indicated by a first position pointing device using electromagnetic induction between the first position pointing device and a tablet;
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the first position pointing device comprising;
a resonance circuit having at least two selectable resonance frequencies;
means for selecting one of the at least two resonance frequencies; and
means for receiving frequency selecting information for the frequency selecting means; andthe tablet comprising;
means for transmitting the frequency selecting information to the receiving means to set an initial resonance frequency in the resonance circuit of the first position pointing device;
means for detecting the first position pointing device having the initial resonance frequency;
means for selectively changing the resonance frequency of the first position pointing device to a second resonance frequency;
means for detecting an additional position pointing device by transmitting a signal equal to the initial resonance frequency; and
means for detecting the first position pointing device using the second resonance frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A position detecting apparatus for detecting a position indicated by a first position pointing device using electromagnetic induction between the first position pointing device and a tablet;
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the first position pointing device comprising;
a resonance circuit having first and second selectable resonance frequencies;
means for selecting one of the first and second resonance frequencies; and
means for receiving frequency selecting information for the frequency selecting means; andthe tablet comprising means for transmitting an electromagnetic wave as the frequency selecting information to the receiving means to set the first resonance frequency in the resonance circuit of the first position pointing device, the electromagnetic wave having a first frequency corresponding to the first resonance frequency of the first position pointing device;
means for selectively changing the resonance frequency of the first position pointing device to the second resonance frequency;
means for detecting an additional position pointing device by transmitting a signal equal to the first resonance frequency, and means for detecting the first position pointing device using the second resonance frequency. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A position detecting apparatus for detecting positions indicated by first and second position pointing devices using electromagnetic induction between the pointing devices and a tablet;
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the first position pointing device comprising;
a resonance circuit having at least two selectable resonance frequencies;
means for selecting one of the at least two resonance frequencies; and
means for receiving frequency selecting information for the frequency selecting means;the second position pointing device comprising;
a resonance circuit having at least two selectable resonance frequencies;
means for selecting one of the at least two resonance frequencies; and
means for receiving frequency selecting information for the frequency selecting means; andthe tablet comprising means for transmitting the frequency selecting information to the receiving means to set an initial resonance frequency in the resonance circuit of the first position pointing device;
means for detecting the first position pointing device having the initial resonance frequency;
means for selectively changing the resonance frequency of the first position pointing device to a second resonance frequency;
means for detecting the second position pointing device by transmitting a signal equal to the initial resonance frequency of the first position pointing device; and
means for detecting the first position pointing device using the second resonance frequency of the first position pointing device. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30)
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31. A method for detecting more than one position pointing device used on a tablet, each position pointing device indicating the position through an electromagnetic induction between the position pointing device and the tablet, and each position pointing device having a resonance circuit having at least two resonance frequencies, the method comprising the steps of:
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scanning for a first position pointing device using a first frequency; detecting a first position pointing device have a resonance circuit with the first frequency as the resonance frequency; changing the resonance frequency of the resonance circuit of the first position pointing device to a second frequency; detecting the position of the first position pointing device using the second frequency; and scanning for a second position pointing device using the first frequency. - View Dependent Claims (32, 33)
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Specification