Tag reading method and apparatus
First Claim
1. A tag reading method for supplying power to at least one of a plurality of superimposed tags and reading information from the tag, comprising the steps of:
- supplying power, which is produced by high-frequency signals, to each tag by generating electromagnetic waves from a plurality of locations by the high-frequency signals and causing the electromagnetic waves to interfere on the tags; and
controlling a phase difference between the high-frequency signals in accordance with the position of a tag from which information is read.
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Accused Products
Abstract
Disclosed in a reading apparatus for supplying power to at least one of a plurality of superimposed RF tags and reading information from the tag while power is being supplied thereto. The apparatus includes means for generating high-frequency signals; electromagnetic wave generating means to which the high-frequency signals are input for generating electromagnetic waves from a plurality of locations, e.g., from both sides of the superimposed tags, by the high-frequency signals and causing the electromagnetic waves to interfere with each other on the tags; means for controlling the phase difference between the high-frequency signals, which are supplied to the electromagnetic wave generating means provided on both sides of the tags, in accordance with the position of a tag from which information is read; and phase shifting means for controlling the phase of at least one high-frequency signal so to produce the phase difference.
9 Citations
20 Claims
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1. A tag reading method for supplying power to at least one of a plurality of superimposed tags and reading information from the tag, comprising the steps of:
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supplying power, which is produced by high-frequency signals, to each tag by generating electromagnetic waves from a plurality of locations by the high-frequency signals and causing the electromagnetic waves to interfere on the tags; and
controlling a phase difference between the high-frequency signals in accordance with the position of a tag from which information is read. - View Dependent Claims (2, 7)
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3. A tag reading method for supplying power to at least one of a plurality of superimposed tags and reading information from the tag, comprising the steps of:
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supplying power, which is produced by a high-frequency signal, to each tag from one side of the superimposed tags;
placing a reflector, which reflects electromagnetic waves produced by the high-frequency signal, on the other side of the tags;
causing the electromagnetic wave and the reflected electromagnetic wave to interfere with each other on the superimposed tags; and
controlling the position of the reflector in accordance with the position of a tag from which information is read.
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4. A tag reading method for supplying power to at least one of a plurality of superimposed tags and reading information from the tag, comprising the steps of:
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supplying power, which is produced by a high-frequency signal, to each tag from one side of the superimposed tags;
placing a reflector, which reflects electromagnetic waves produced by the high-frequency signal, on the other side of the tags;
causing the electromagnetic wave and the reflected electromagnetic wave to interfere with each other on the superimposed tags; and
controlling reflectivity of the reflector in accordance with the position of a tag from which information is read.
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5. A tag reading method for supplying power to at least one of a plurality of superimposed tags and reading information from the tag, comprising the steps of:
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supplying power, which is produced by a high-frequency signal, to each tag by generating electromagnetic waves from a plurality of locations by the high-frequency signal and causing the electromagnetic waves to interfere on the tags;
causing the high-frequency signal to branch at a branch point;
imparting a difference in propagation length between propagation lengths from the branch point to points at which respective ones of the electromagnetic waves are generated;
when the frequency of the high-frequency signal is changed from a low frequency to a high frequency, deciding the difference in propagation length in such a manner that a phase difference between the branched high-frequency signals is rotated by a required angle; and
controlling the frequency of the high-frequency signal in accordance with the position of a tag from which information is read. - View Dependent Claims (6)
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8. A tag reading method for supplying power to at least one of a plurality of superimposed tags and reading information from the tag, comprising the steps of:
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placing a transmission line along which there is leakage of electromagnetic waves at the periphery of the superimposed tags;
causing a high-frequency signal to branch and inputting the branched high-frequency signals to respective ones of both ends of the transmission line to thereby cause the signals to interfere with each other;
controlling a phase difference between the branched high-frequency signals in accordance with the position of a tag from which information is read; and
causing electromagnetic waves to leak from the transmission line to thereby supply power, which is produced by the high-frequency signal, to the tag.
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9. A tag reading method for supplying power to at least one of a plurality of superimposed tags and reading information from the tag, comprising the steps of:
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placing a transmission line along which there is leakage of electromagnetic waves at the periphery of the superimposed tags;
inputting a high-frequency signal to one end of the transmission line and connecting a reflecting circuit, which is for reflecting the high-frequency signal, to the other end of the transmission line;
controlling reflectivity of the reflecting circuit in accordance with the position of a tag from which information is read; and
causing the high-frequency signal and the reflected high-frequency signal to interfere with each other and causing electromagnetic waves to leak from the transmission line to thereby supply power, which is produced by the high-frequency signal, to the tag.
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10. A tag reading method for supplying power to at least one of a plurality of superimposed tags and reading information from the tag, comprising the steps of:
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placing a transmission line along which there is leakage of electromagnetic waves at the periphery of the superimposed tags;
causing a high-frequency signal to branch at a branch point and inputting the branched high-frequency signals to respective ones of both ends of the transmission line to thereby cause the signals to interfere with each other;
imparting a difference in propagation length between propagation lengths from the branch point to both ends of the transmission line;
when the frequency of the high-frequency signal is changed from a low frequency to a high frequency, deciding the difference in propagation length in such a manner that a phase difference between the branched high-frequency signals is rotated by a required angle;
controlling the frequency of the high-frequency signal in accordance with the position of a tag from which information is read; and
causing electromagnetic waves to leak from the transmission line to thereby supply power, which is produced by the high-frequency signal, to the tag.
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11. A tag reading apparatus for supplying power to at least one of a plurality of superimposed tags and reading information from the tag, comprising:
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means for generating high-frequency signals;
electromagnetic wave generating means to which the high-frequency signals are input for generating electromagnetic waves from a plurality of locations by the high-frequency signals and causing the electromagnetic waves to interfere on the tags;
means for deciding a phase difference between the high-frequency signals in accordance with the position of a tag from which information is read; and
phase shifting means for controlling the phase of at least one high-frequency signal so to produce the phase difference. - View Dependent Claims (12, 17)
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13. A tag reading apparatus for supplying power to at least one of a plurality of superimposed tags and reading information from the tag, comprising:
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means for generating a high-frequency signal;
electromagnetic wave generating means to which the high-frequency signal is input for generating electromagnetic waves from one side of the superimposed tags by the high-frequency signal;
a reflector provided on the other side of the tags for reflecting the electromagnetic waves produced by the high-frequency signal and causing the electromagnetic waves and the reflected electromagnetic waves to interfere on the superimposed tags;
moving means for moving said reflector; and
control means for controlling the position of the reflector in accordance with the position of a tag from which information is read.
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14. A tag reading apparatus for supplying power to at least one of a plurality of superimposed tags and reading information from the tag, comprising:
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means for generating a high-frequency signal;
electromagnetic wave generating means to which the high-frequency signal is input for generating electromagnetic waves from one side of the superimposed tags by the high-frequency signal;
a reflector provided on the other side of the tags for reflecting the electromagnetic waves produced by the high-frequency signal and causing the electromagnetic waves and the reflected electromagnetic waves to interfere on the superimposed tags;
reflectivity changing means for changing reflectivity of said reflector; and
control means for controlling reflectivity of said reflector in accordance with the position of a tag from which information is read.
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15. A tag reading apparatus for supplying power to at least one of a plurality of superimposed tags and reading information from the tag, comprising:
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means for generating a high-frequency signal;
branching means for branching the high-frequency signal at a branch point;
electromagnetic wave generating means for generating electromagnetic waves from a plurality of locations by the branched high-frequency signals and causing the electromagnetic waves to interfere on the tags;
a propagation path which, when the frequency of the high-frequency signal is changed from a low frequency to a high frequency, is for imparting a difference in propagation length between propagation lengths from the signal branch point to points at which the electromagnetic waves are generated, in such a manner that a phase difference between the branched high-frequency signals is rotated by a required angle; and
control means for controlling the frequency of the high-frequency signal in accordance with the position of a tag from which information is read. - View Dependent Claims (16)
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18. A tag reading apparatus for supplying power to at least one of a plurality of superimposed tags and reading information from the tag, comprising:
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a transmission line, which is provided at the periphery of the superimposed tags, along which there is leakage of electromagnetic waves;
means for generating a high-frequency signal;
means for branching the high-frequency signal and inputting the branched high-frequency signals to respective ones of both ends of said transmission line;
means for deciding a phase difference between the branched high-frequency signals based upon the position of a tag from which information is read; and
means for controlling the phase of at least one high-frequency signal so as to produce the phase difference;
wherein electromagnetic waves are caused to leak from said transmission line to thereby supply power, which is produced by the high-frequency signal, to the tag.
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19. A tag reading apparatus for supplying power to at least one of a plurality of superimposed tags and reading information from the tag, comprising:
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a transmission line, which is provided at the periphery of the superimposed tags, along which there is leakage of electromagnetic waves;
means for generating a high-frequency signal and inputting a high-frequency signal to one end of said transmission line;
a reflecting circuit connected to the other end of said transmission line for reflecting the high-frequency signal; and
means for controlling reflectivity of said reflecting circuit in accordance with the position of a tag from which information is read;
wherein the high-frequency signal and the reflected high-frequency signal are made to interfere with each other and electromagnetic waves are caused to leak from the transmission line to thereby supply power, which is produced by the high-frequency signal, to the tag.
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20. A tag reading apparatus for supplying power to at least one of a plurality of superimposed tags and reading information from the tag, comprising:
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a transmission line, which is provided at the periphery of the superimposed tags, along which there is leakage of electromagnetic waves;
means for generating a high-frequency signal;
means for branching the high-frequency signal at a branch point and inputting the branched high-frequency signals to respective ones of both ends of said transmission line;
a propagation path which, when the frequency of the high-frequency signal is changed from a low frequency to a high frequency, is for imparting a difference in propagation length between propagation lengths from the signal branch point to points at which the electromagnetic waves are generated, in such a manner that a phase difference between the branched high-frequency signals is rotated by a required angle; and
control means for controlling the frequency of the high-frequency signal in accordance with the position of a tag from which information is read.
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Specification