EP0540345A1
Expired / Lapsed
EP
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Method and apparatus for recording and reproducing information
Assignee: Canon Inc
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Filing: 1992-10-30
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Granted: —
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Expires: 2012-10-30
Abstract
Abstract Information represented by arrangement of codes of three or more kinds is recorded on a recording medium having a track as following manner. The codes of the information is caused to correspond to information pits of three or more kinds respectively. The information pit corresponding to each code is formed on the track so as to be arranged along the track. Each information pit is recognized by the length thereof along the longitudinal direction of the track and the distance between the center of the pit in the longitudinal direction of the track and a reference position determined by a reference clock.
Inventors
- 👤 Masakuni C/O Canon Kabushiki Kaisha Yamamoto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 10:29
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/2407; G11B7/24085; G11B20/00; G11B20/10; G11B20/16; G11B7/004; G11B7/0045; G11B7/005; G11B7/12; G11B7/13
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
114 words
A method for recording information, represented by the arrangement of codes of at least three kinds, on a recording medium having a track, comprising steps of: making the codes of said information to respectively correspond to information pits of at least three kinds; and forming the information pits corresponding to the codes on the recording medium, in an arrangement along the track, wherein the information pits of different kinds can be mutually identified by the length along the longitudinal direction of track, and the distance along the longitudinal direction of track between the center of pit on the recording medium and a reference position determined on the medium according to a reference clock signal.
Claim 2
Dependent Claim
26 words
A method according to claim 1, wherein said information pit is recorded by forming a projection or a recess on the substrate of said recording medium.
Claim 3
Dependent Claim
32 words
A method according to claim 1, wherein said recording medium is composed of a magneto-optical recording medium, and said information pit is recorded by forming a magnetic domain on said recording medium.
Claim 4
Independent Claim
102 words
A method for recording information, represented by the arrangement of codes of at least three kinds, on a recording medium having a track, comprising steps of: setting, on said track, reference positions at predetermined intervals corresponding to a reference clock signal; and recording information pits, corresponding to the codes of said information, respectively on said reference positions, wherein the information pits corresponding to different codes are mutually different in the length along the longitudinal direction of said track and/or in the amount of shift from the reference position to the center position of said pits in the longitudinal direction of the track.
Claim 5
Dependent Claim
26 words
A method according to claim 4, wherein said information pit is recorded by forming a projection or a recess on the substrate of said recording medium.
Claim 6
Dependent Claim
32 words
A method according to claim 4, wherein said recording medium is composed of a magneto-optical recording medium, and said information pit is recorded by forming a magnetic domain on said recording medium.
Claim 7
Independent Claim
121 words
A method for reproducing information from a recording medium bearing an arrangement, along a track, of information pits of at least three kinds which are mutually different in the length along the longitudinal direction of track and/or in the amount of shift from a reference position corresponding to a reference clock signal to the center position of said information pit along the longitudinal direction of track, comprising steps of: scanning said track with a light spot; detecting, in synchronization with said reference clock signal, the light amount distribution of the reflected or transmitted light when the information pit is irradiated by the light spot; and reproducing information by identifying the kinds of information pits based on the detected light amount distribution.
Claim 8
Independent Claim
130 words
An apparatus for reproducing information from a recording medium bearing an arrangement, along a track, of information pits of at least three kinds which are mutually different in the length along the longitudinal direction of track and/or in the amount of shift from a reference position corresponding to a reference clock signal to the center position of-the information pit in the longitudinal direction of track, comprising: means for scanning said track with a light spot; a photodetector for detecting, in synchronization with said reference clock signal, the light amount distribution of the reflected or transmitted light when the information pit is irradiated by the light spot; and an information recognition circuit for reproducing the information by identifying the kinds of the information pits based on the detected light amount distribution.
Claim 9
Dependent Claim
58 words
An apparatus according to claim 8, wherein said information recognition circuit includes memory means storing the light amount distributions obtained from the information pits of different kinds, and identification means for identifying the kinds of the information pits by calculating the correlation between the light amount distribution obtained by the photodetector and that stored in the memory means.
Claim 10
Dependent Claim
17 words
An apparatus according to claim 8, wherein said information recognition circuit is composed of a neural network.
Claim 11
Dependent Claim
52 words
An apparatus according to claim 10, wherein said photodetector has a light receiving face divided into plural elements, and said neural network includes a circuit for weighting the outputs from said divided elements, and a circuit for identifying the kind of the information pit by effecting calculation on the weighted plural outputs.
Claim 12
Dependent Claim
53 words
An apparatus according to claim 11, wherein said information pit is composed of a projection or a recess formed on the substrate of said recording medium, with a height or a depth equal to λ/4n wherein n is the refractive index of the substrate while λ is the wavelength of the light spot.
Claim 13
Dependent Claim
96 words
An information recording and/or reproducing method or apparatus or an information carrier in which at least 3 value levels are encoded in spots recorded along an information carrier track, a spot of a first value level differing from a spot of a second value level at least in its extent in the direction along the track and a spot of a third value level different from a spot of the first value level at least in its position, relative to a respective one of a predetermined series of reference positions, in the direction along the track.
Claim 14
Dependent Claim
23 words
A method, apparatus or carrier according to claim 13 in which a spot is defined by an optical difference from the surrounding background.
Claim 15
Dependent Claim
19 words
A method, apparatus or carrier according to claim 14 in which the optical difference is a difference in height.
Claim 16
Dependent Claim
23 words
A method, apparatus or carrier according to claim 13 in which a spot is defined by a magnetic difference from the surrounding background.
References Cited (Backward Citations)
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