EP0265984A1
Expired / Lapsed
EP
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Optically readable record carrier for recording information, method and apparatus for manufacturing such a record carrier, apparatus for recording information on such a record carrier, and apparatus for reading information recorded on such a record carrier
Assignee: Koninklijke Philips NV
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Filing: 1987-10-05
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Granted: —
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Expires: 2007-10-05
Abstract
Abstract A record carrier (40) comprises a radiation-sensitive layer (43) upon a disc-shaped substrate (42) and is provided with an information-recording area arranged in accordance with a spiral-shaped or concentric pattern of preformed tracks (41). The track exhibits a track modulation in the form of a radial wobble whose frequency is modulated with a position-information signal (Ip). Further, an apparatus (1) is disclosed for forming the track pattern during the manufacture of the record carrier (40). When an information signal (Vi) is recorded on the record carrier (40) and the recorded signal is read an FM demodulation device (60) recovers the position-information signal Ip from the variations in the scanning beam (54, 54a) produced by the track modulation. Moreover, a clock signal for the purpose of scanning-velocity control is recovered from these variations in the scanning beam.
Inventors
- 👤 Wilhelmus Petrus Maria Raaymakers
- 👤 Franciscus Lambertus Johannus Maria Kuijpers
- 👤 Aartje Willemina Veenis
- 👤 Johannes Hermanus Theodorus Pasman
- 👤 Hendricus Antonius Maria Mulder
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 13:11
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/26; G11B27/00; G11B27/10; G11B27/19; G11B27/24; G11B23/00; G11B23/0057; G11B27/28; G11B27/30; G11B27/3027; G11B7/2407; G11B7/24073; G11B7/24082; G11B7/261; G11B2220/00; G11B2220/20; G11B2220/21; G11B2220/215; G11B2220/218; G11B2220/25; G11B2220/2537; G11B2220/2545
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
79 words
An optically readable record carrier comprising a radiation-sensitive layer upon a disc-shaped substrate and provided with an information recording area arranged in accordance with a spiral or concentric track pattern, which record carrier is intended for the recording and/or reproduction of the information in the information recording area by means of a radiation beam, which information recording area exhibits a periodic track modulation, characterized in that the frequency of the track modulation is modulated with a digital position-information signal.
Claim 2
Dependent Claim
79 words
An optically readable record carrier comprising a radiation-sensitive layer upon a disc-shaped substrate and provided with an information recording area arranged in accordance with a spiral or concentric track pattern, which record carrier is intended for the recording and/or reproduction of the information in the information recording area by means of a radiation beam, which information recording area exhibits a periodic track modulation, characterized in that the frequency of the track modulation is modulated with a digital position-information signal.
Claim 3
Dependent Claim
72 words
A record carrier as claimed in Claim 1, in which the clock signal is utilized for controlling the velocity with which the information-recording area is scanned by the radiation beam during recording and/or reproduction, characterized in that at the nominal scanning velocity of the information-recording area the frequency components produced in the clock signal by the digital position-information signal are situated at least substantially outside the frequency band used for velocity control.
Claim 4
Dependent Claim
50 words
A record carrier as claimed in any one of the preceding Claims, characterized in that the position-information signal indicates the time necessary for covering the distance from the beginning of the track pattern to the location where the position-inform ation is present when scanning is effected with the nominal velocity.
Claim 5
Dependent Claim
42 words
A record carrier as claimed in any one of the preceding Claims, the information area being provided with a track modulation in the form of a periodic radial wobble of the track, characterized in that the periodic wobble exhibits the frequency modulation.
Claim 6
Dependent Claim
31 words
A record carrier as claimed in Claim 4, characterized in that the track is constituted by substantially spiral-shaped or concentric ridges of substantially constant width, which ridges exhibit the radial wobble.
Claim 7
Dependent Claim
26 words
A record carrier as claimed in Claim 5, characterized in that the width of the ridges is larger than the average width of the intermediate grooves.
Claim 8
Dependent Claim
119 words
A method of manufacturing a record carrier as claimed in Claim 5, a master disc provided with a track pattern being obtained by scanning a substrate provided with a radiation-sensitive layer with a radiation beam along substantially concentric or spiral-shaped paths which exhibit a radial wobble, the scanned portions of the radiation-sensitive layer being removed by subsequently developing the radiation-sensitive layer of the substrate, characterized in that the information layer is scanned along a path which is the complement of the desired path of the track on the record carrier to be manufactured, the record carrier with a track pattern which is the complement of the track pattern on the master disc being manufactured starting from the master disc.
Claim 9
Dependent Claim
111 words
A method of manufacturing a record carrier as claimed in Claim 5, a master disc being obtained by scanning a substrate provided with a radiation-sensitive layer with a radiation beam along a path corresponding to the desired spiral-shaped or concentric path of the track on the record carrier to be manufactured, which track is provided with a radial wobble and by subsequent local removal of the radiation-sensitive layer by developing said layer, after which the record carriers are obtained by copying the track pattern on the master disc, characterized in that the radiation-sensitive layer is constituted by a radiation-sensitive material of which exclusively the non-exposed portions can be removed by development.
Claim 10
Independent Claim
83 words
An apparatus for manufacturing a record carrier as claimed in any one of the Claims 1 to 6, comprising a writing device for writing the track pattern by means of a radiation beam and a control device for generating a periodic control signal for the writing device so as to obtain a track modulation whose frequency corresponds to the frequency of the periodic control signal, characterized in that the apparatus comprises frequency-modulation means for frequency-modulating the control signal with a digital position-information signal.
Claim 11
Dependent Claim
51 words
An apparatus as claimed in Claim 9, characterized in that the apparatus comprises means for generating a digital position-information signal indicating the time necessary for covering the distance from the beginning of the track to the location where the digital position-information is recorded when scanning is effected with the nominal velocity.
Claim 12
Independent Claim
85 words
An apparatus for recording information on a record carrier as claimed in any one of the Claims 1 to 6, comprising means for scanning the information-recording area by means of a radiation beam, a modulation device for modulating the radiation beam depending on an information signal, an optical system with a detector for detecting the radiation reflected or transmitted by the record carrier during scanning, characterized in that the recording apparatus comprises an FM demodulation device for recovering the position-information signal from the clock signal.
Claim 13
Independent Claim
112 words
An apparatus for reading a record carrier as claimed in any one of the Claims 1 to 6, on which record carrier an information signal is recorded in the information-recording area, comprising a scanning device for scanning the information-recording area with a substantially constant velocity by me ans of a radiation beam, an optical system with a detector for detecting the radiation reflected or transmitted by the record carrier during scanning by means of a device for deriving from the radiation detected by the detector an information signal representing the recorded information, characterized in that the reading apparatus comprises an FM demodulation device for recovering the position-information signal from the clock signal.
References Cited (Backward Citations)
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