EP0320975A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Information recording/reproducing method and apparatus
Assignee: Hitachi Ltd
•
Filing: 1988-12-16
•
Granted: —
•
Expires: 2008-12-16
Abstract
Abstract Data recording and/or reproduction on or from a recording medium (1) on which tracking signal detection marks (2; 74-83) are intermittently provided along each track in a pattern wobbling alternately across the track center line with a very small lateral displacement therefrom, wherein data recording areas (D) are defined between king signal detection marks. A servo control system (12) for controlling a write/read light spot (4) so as to follow the track with the aid of a tracking signal obtained by detecting the tracking signal detection marks is provided with a low-pass filter circuit (11) having a cut-off frequency lower than the frequency at which the tracking signal detection marks (2) are detected. A data is recorded or reproduced on or from the recording areas (D) of the recording medium while following the track under the control of the servo system. A blank area (X s ) where data recording is inhibited is provided between the data recording area and the tracking signal detecting mark (prepit) to suppress interference of the mark to the data. A specific access prepit pattern (Figs. 12 to 15) which allows track addresses to be at least approximately detected upon passing of the light spot (4) over the tracks of the recording medium is previously provided together with synchronizing marks (84, 85, 86, 87) is a synchronizing area (SYNC).
Inventors
- 👤 Takeshi Maeda
- 👤 Yoshito Tsunoda
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 22:55
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/0938; G11B11/00; G11B11/10; G11B11/105; G11B11/1055; G11B11/10556; G11B11/10563; G11B11/10565; G11B11/10576; G11B11/10578; G11B21/00; G11B21/02; G11B21/10; G11B21/106
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
135 words
A method of recording and/or reproducing information on or from a recording medium (1) on which tracking signal detecting marks (2) are intermittently provided along each track in a pattern wobbling alternately across the track center with a very small displacement therefrom, wherein data recording areas (D) are defined between said marks (2; 74, 75, 76, 77, 78, 79, 80, 81, 82, 83) and a tracking signal is obtained by detecting said tracking signal detecting marks, characterized in that a data is recorded or reproduced on or from said recording areas while following the track by means of a servo system (12) including a low-pass filter circuit (11; 42) having a cut-off frequency which is lower than a frequency at which said tracking signal detecting marks make appearance in the course of the detection thereof.
Claim 2
Independent Claim
135 words
A method of recording and/or reproducing information on or from a recording medium (1) on which tracking signal detecting marks (2) are intermittently provided along each track in a pattern wobbling alternately across the track center with a very small displacement therefrom, wherein data recording areas (D) are defined between said marks (2; 74, 75, 76, 77, 78, 79, 80, 81, 82, 83) and a tracking signal is obtained by detecting said tracking signal detecting marks, characterized in that a data is recorded or reproduced on or from said recording areas while following the track by means of a servo system (12) including a low-pass filter circuit (11; 42) having a cut-off frequency which is lower than a frequency at which said tracking signal detecting marks make appearance in the course of the detection thereof.
Claim 3
Independent Claim
110 words
A method of recording and/or reproducing information on or from a recording medium on which wobbling prepits (2, 74-83) are intermittently provided along each track in a pattern wobbling alternately across the track center with a very small displacement therefrom, wherein data recording areas (D) are defined between said prepits, characterized in that a synchronizing prepit (84, 85; 86, 87; 95, 96; 88, 89, 97) is provided for every predetermined number of pairs of said wobbling prepits (2; 74-83), and that positional information for the access to the track is detected by detecting the phase of said wobbling prepits with the aid of a signal derived from said synchronizing prepits.
Claim 4
Independent Claim
110 words
A method of recording and/or reproducing information on or from a recording medium on which wobbling prepits (2, 74-83) are intermittently provided along each track in a pattern wobbling alternately across the track center with a very small displacement therefrom, wherein data recording areas (D) are defined between said prepits, characterized in that a synchronizing prepit (84, 85; 86, 87; 95, 96; 88, 89, 97) is provided for every predetermined number of pairs of said wobbling prepits (2; 74-83), and that positional information for the access to the track is detected by detecting the phase of said wobbling prepits with the aid of a signal derived from said synchronizing prepits.
Claim 5
Dependent Claim
189 words
An information recording/reproducing apparatus for recording and/or reproducing information on or from a recording medium (1) on which tracking signal detecting marks (2; 74-83) are intermittently provided along each track in a pattern wobbling alternately across the track center with a very small displacement therefrom, wherein data recording areas (D) are defined between said marks (2; 74-83), characterized by a head (104) for illuminating said data recording areas (D) of said recording medium (1) with a light beam (4), a track deviation detecting circuit (114) for obtaining a tracking signal by detecting said tracking signal detecting marks by sampling with said light beam, and a servo system (12) including a control circuit (109) for performing control operation with the aid of said tracking signal such that said light beam follows said track, and that said servo system includes a low-pass filter circuit (11; 42) having a cut-off frequency lower than the frequency at which said tracking signal detecting marks are detected, wherein a data is recorded or reproduced on or from said recording area of said recording medium (1) while following the track by means of said servo system.
Claim 6
Dependent Claim
189 words
An information recording/reproducing apparatus for recording and/or reproducing information on or from a recording medium (1) on which tracking signal detecting marks (2; 74-83) are intermittently provided along each track in a pattern wobbling alternately across the track center with a very small displacement therefrom, wherein data recording areas (D) are defined between said marks (2; 74-83), characterized by a head (104) for illuminating said data recording areas (D) of said recording medium (1) with a light beam (4), a track deviation detecting circuit (114) for obtaining a tracking signal by detecting said tracking signal detecting marks by sampling with said light beam, and a servo system (12) including a control circuit (109) for performing control operation with the aid of said tracking signal such that said light beam follows said track, and that said servo system includes a low-pass filter circuit (11; 42) having a cut-off frequency lower than the frequency at which said tracking signal detecting marks are detected, wherein a data is recorded or reproduced on or from said recording area of said recording medium (1) while following the track by means of said servo system.
Claim 7
Dependent Claim
182 words
An information recording/reproducing apparatus for recording and/or reproducing information on or from a recording medium on which wobbling prepits (2; 74-83) are intermittently provided along each track in a pattern wobbling alternately across the track center with a very small displacement therefrom, wherein data recording areas (D) are defined between said prepits, characterized by a synchronizing prepit (84, 85; 86, 87; 95, 96; 88, 89, 97) provided for every predetermined number of pairs of said wobbling prepits (2; 74-83), a head 104) for illuminating said data recording areas (D) on said recording medium (1) with a light beam (4), a servo system (12) including a track deviation detecting circuit (114) for obtaining a tracking signal by detecting said prepits through sampling with said light beam (4) and a control circuit (109) for performing control operation with the aid of said tracking signal such that said light beam follows said track, and positional information detecting means (Fig. 11) for detecting positional information for access by detecting the phase of said wobbling prepits with the aid of a signal obtained from said synchronizing prepit.
Claim 8
Dependent Claim
182 words
An information recording/reproducing apparatus for recording and/or reproducing information on or from a recording medium on which wobbling prepits (2; 74-83) are intermittently provided along each track in a pattern wobbling alternately across the track center with a very small displacement therefrom, wherein data recording areas (D) are defined between said prepits, characterized by a synchronizing prepit (84, 85; 86, 87; 95, 96; 88, 89, 97) provided for every predetermined number of pairs of said wobbling prepits (2; 74-83), a head 104) for illuminating said data recording areas (D) on said recording medium (1) with a light beam (4), a servo system (12) including a track deviation detecting circuit (114) for obtaining a tracking signal by detecting said prepits through sampling with said light beam (4) and a control circuit (109) for performing control operation with the aid of said tracking signal such that said light beam follows said track, and positional information detecting means (Fig. 11) for detecting positional information for access by detecting the phase of said wobbling prepits with the aid of a signal obtained from said synchronizing prepit.
Claim 9
Dependent Claim
32 words
The invention of any of claims 1 to 4, wherein the cut-off frequency of said low-pass filter circuit (11; 42) is higher than a frequency band required bY said servo system 12
Claim 10
Dependent Claim
51 words
The invention of any of claims 1 to 5, wherein a blank area (X s ) where no data is recorded is provided between said tracking signal detecting mark (2) and said data recording area (D) to thereby reduce interference between said mark and the data recorded in said recording area.
Claim 11
Dependent Claim
67 words
The invention of any of claims 1 to 6, wherein a synchronizing mark (84, 85; 86, 87, 95, 96; 88, 89, 97) is provided in said recording area for every predetermined number of pairs of said tracking signal detecting marks, and that a timing signal for sampling said tracking signal detecting marks is generated on the basis of said synchronizing marks and said tracking signal detecting marks.
Claim 12
Dependent Claim
48 words
The invention of any of claims 1 to 7, wherein the phase of the clock signal obtained from said tracking signal detecting marks is so shifted as to coincide with the phase of a reproduced signal of said data for deriving said clock signal for demodulating said data.
Claim 13
Dependent Claim
26 words
The invention of claim 7 or 8, wherein address signal marks for access (B13, ..., B5, ..., B0) are provided together with said synchronizing mark (SYNC).
Claim 14
Dependent Claim
23 words
The invention of claim 9, wherein at least more significant bits (B₁₃, ..., B5) of said address signal are provided between the tracks.
Claim 15
Dependent Claim
32 words
The invention of claim 9 or 10, wherein positions of said tracking signal detecting marks are displaced in accordance with at least less significant bits (B4, ..., B0) of said address signal.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.