Position detecting apparatus and pointing device thereof
First Claim
1. A position detecting system which detects positions of at least two different cordless pointing devices on a two-dimensional plane and is equipped with a command electromagnetic-wave transmitting circuit for transmitting a command to said pointing devices, the position detecting system comprising:
- a first group of antennae arranged successively in a first one of two directions orthogonal to each other within said two-dimensional plane;
a second group of antennae arranged successively in a second of the two directions that is orthogonal to said first direction within said two-dimensional plane;
selection means for selecting at least an antenna of said first and second antennae groups, which allows transmission of an electromagnetic wave to a first one of said pointing devices to be measured, said electromagnetic wave from the selected antenna being more strongly coupled to said first pointing device than to the other or second pointing device; and
transmission means for transmitting said electromagnetic wave from said antenna, selected by said selection means, to said first pointing device to be measured.
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Accused Products
Abstract
A position detecting system capable of making communications with a plurality of pointing devices without changing resonance circuits of said pointing devices, and a pointing device suitable for the position detecting system. The position detecting system detects positions of at least two cordless pointing devices on a two-dimensional plane and is equipped with a command electromagnetic wave transmitting circuit to transmit a command to the pointing device. Included in the position detecting system are a first group of antennae X1 to X11 arranged successively in one of the directions orthogonal to each other within the two-dimensional plane 11, a second group of antennae Y1 to Y8 arranged successively in the other direction orthogonal to the one direction within the two-dimensional plane 11, a selection circuit for, from the first and second antenna groups, selecting an antenna which is more strongly coupled to the pointing device to be measured than to the other pointing device in transmitting an electromagnetic wave, and a transmission circuit for transmitting an electromagnetic wave from the selected antenna to the pointing device to be measured.
68 Citations
11 Claims
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1. A position detecting system which detects positions of at least two different cordless pointing devices on a two-dimensional plane and is equipped with a command electromagnetic-wave transmitting circuit for transmitting a command to said pointing devices, the position detecting system comprising:
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a first group of antennae arranged successively in a first one of two directions orthogonal to each other within said two-dimensional plane; a second group of antennae arranged successively in a second of the two directions that is orthogonal to said first direction within said two-dimensional plane; selection means for selecting at least an antenna of said first and second antennae groups, which allows transmission of an electromagnetic wave to a first one of said pointing devices to be measured, said electromagnetic wave from the selected antenna being more strongly coupled to said first pointing device than to the other or second pointing device; and transmission means for transmitting said electromagnetic wave from said antenna, selected by said selection means, to said first pointing device to be measured. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A pointing device having a resonance circuit at least comprising a coil and a capacitor, and used in connection with a position detecting system without requiring a cord between said pointing device and said position detecting system, said pointing device comprising:
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a reception circuit for receiving external command information from the detecting system; and a resonance state changing circuit for changing a resonance state of said resonance circuit in accordance with said command information which the reception circuit receives. - View Dependent Claims (9, 10)
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11. A position detecting system for detecting positions of first and second pointing devices that are on a two-dimensional coordinate plane at the same time, the position detecting system comprising:
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scanning means for scanning a plurality of X-axial antenna elements and Y-axial antenna elements at an initial resonant frequency f0 in order to obtain and measure reception signal strengths of said first and second pointing devices on said two-dimensional plane and allow approximate position measurement of said first and second pointing devices which are both initially receptive to said initial frequency f0 ; selection means for selecting at least a first antenna element based upon the measured signal strengths obtained by said scanning means, said selected first antenna element when transmitting being more strongly coupled to said first pointing device than to said second pointing device, said selected antenna element for transmitting a command signal to said first pointing device in order to change the resonant frequency of said first pointing device from said initial frequency f0 to a second different resonant frequency f1 so that said first pointing device is no longer receptive to said initial resonant frequency f0 and so that said first and second pointing devices on said two-dimensional plane are receptive to different resonant frequencies; and detection means for measuring the coordinate position of said first pointing device based upon signals transmitted at said second resonant frequency f1.
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Specification