EP0545472A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Closed information system with physical copy protection
Assignee: Koninklijke Philips NV
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Filing: 1992-11-25
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Granted: —
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Expires: 2012-11-25
Abstract
Abstract An information system comprises a record carrier (1) and a playback apparatus. Information have been recorded on the record carrier (1) in the form of variations of a first physical parameter. The playback apparatus scans the record carrier by means of a transducer (41) which is responsive to said variations of said first physical parameter. An information recovering circuit (42) recovers the information from a detection signal received from the transducer (41). The record carrier (1) exhibits a second variation of a second physical parameter, which differs from said first physical parameter but which is of type that is detectable by means of said transducer (41). A detection circuit (43) detects the a presence of the second variation on the basis of a detection signal received from the transducer (41). A circuit (44) responsive to the detection means enables the information recovering circuit (42) in the event that the presence of said second variations is detected. Copying machines of usual types only copies the variations in physical parameters which represent the information without copying the variations of the second physical parameter. The information on copy obtained by means of such copying machine can not be recovered. So copying of record carriers is made less easily.
Inventors
- 👤 Jozef Maria Karel Timmermans
- 👤 Erik Christian Schylander
- 👤 Johannes Jan Mons
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 02:20
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/007; G11B7/00736; G11B19/00; G11B19/02; G11B19/04; G11B19/12; G11B20/00; G11B20/00086; G11B20/0021; G11B20/00217; G11B20/00253; G11B20/00405; G11B20/00485; G11B20/00492; G11B20/00572; G11B20/00586; G11B20/00594; G11B20/00601; G11B20/10; G11B20/18; G11B20/1806; G11B20/1809; G11B5/00; G11B5/74; G11B5/86; G11B7/24; G11B7/2407; G11B7/24073; G11B7/24082; G11B7/24085; H; H04; H04N; H04N5/00; H04N5/76; H04N5/91; H04N5/913; G11B13/00; G11B23/00; G11B23/28; G11B23/283; G11B23/284; G11B5/012; G11B7/002; G11B7/0037; G11B7/004; G11B7/005; G11B7/08; G11B7/09; G11B7/0901; G11B7/0938; G11B9/00; H04N2005/91307; H04N2005/91342; H04N2005/91357; H04N2005/91364
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
153 words
Information system comprising a record carrier on which information have been recorded in the form of variations of a first physical parameter and a playback apparatus provided with means for scanning the record carrier by means of a transducer which is responsive to said variations of said first physical parameter, means for recovering the information from a detection signal received from said transducer, characterized in that said record carrier exhibits a second variation of a second physical parameter, which differs from said first physical parameter but which is of type that is detectable by means of said transducer, and in that the playing apparatus comprises detection means for a detection of a presence of said second variation on the basis of a detection signal received from the transducer, means responsive to the detection means for enabling the recovery of the information in the event that the presence of said second variations is detected.
Claim 2
Dependent Claim
51 words
Information system as claimed in claim 1, characterized in that the second variation exhibits a modulation pattern representing a code, that the detection means comprises demodulation means for recovering the said code from the detection signal and means for activating the enabling means in response to the recovery of said code.
Claim 3
Dependent Claim
77 words
Information system as claimed in claim 2 , characterized the information recorded is of a type which is recoverable by means of a predetermined data processing, the code represented by the modulation pattern of the second variation indicating the type of data processing to be used for recovering the information, the apparatus being provided with means for setting the recovery means in a mode in which the predetermined data processing indicated by the code recovered is performed.
Claim 4
Dependent Claim
65 words
Information system as claimed in one of the preceding claims, characterized in that said record carrier is of an optical readable type, in which the information has been recorded a patterns of optically detectable marks arranged along a track, and in that said transducer comprises a radiation sensitive detector and means for directing a radiation beam on the radiation sensitive detector via the record carrier,
Claim 5
Dependent Claim
106 words
Information system as claimed in claim 4, characterized by servo control means for controlling the scanning in order to control at least one scanning parameter to a predetermined value on the basis of a detection signal received from the radiation sensitive detector and which is affected by said second physical parameter, which servo control means having a predetermined frequency bandwidth, said variation of said second physical parameter causes variations in the detection signal which exhibit a frequency spectrum which is located outside the bandwidth of servo control means and outside the frequency spectrum of the signal variations caused by the variation of the first physical parameter.
Claim 6
Dependent Claim
36 words
Information system as claimed in claim 5, characterized in that said servo control tracking control means, the variations of the second physical parameter being variations in track position in a direction transverse to the track direction.
Claim 7
Dependent Claim
72 words
Information system as claimed in claim 5 characterized in that the servo control means comprises scanning speed control means, the variations of the second physical parameter being the mean value of the length of the optically detectable areas and the intermediate areas, the player apparatus comprising means for data clock recovery, the detection means comprises means for detecting variations in the clock frequency caused by the variation in the said mean value.
Claim 8
Dependent Claim
58 words
Information system as claimed in claim 5, characterized that the servo control means comprises focus control means for maintaining a focal point of the scanning beam substantially in the plane in which the optically detectable areas and the intermediate ares are located, the variation of the second physical parameter being variation in the position of the said plane.
Claim 9
Dependent Claim
67 words
Information system as claimed in one of the claims 6, 7 or 8, characterized in that the record carrier is a Compact Disc, and that the variations in the second physical parameter result in a variation in the detection signal with a frequency substantially corresponding to 22 kHz in the event that the track is scanned with a scanning speed between 1.2 to 1.4 meter per second.
Claim 10
Dependent Claim
135 words
A playback apparatus for playing a record carrier on which information have been recorded in the form of variations of a first physical parameter, the playback apparatus being provided with means for scanning the record carrier by means of a transducer which is responsive to said variations of said first physical parameter, means for recovering the information from a detection signal received from said transducer, characterized in that the playing apparatus comprises detection means for a detection of a presence of a second variation of a second physical parameter, which differs from said first physical parameter said second variation on the basis of a detection signal received from the transducer, means responsive to the detection means for enabling the recovery of the information in the event that the presence of said second variations is detected.
Claim 11
Dependent Claim
39 words
Playback apparatus as claimed in claim 10, characterized in that the detection means comprises demodulation means for recovering a code from the detection signal and means for activating the enabling means in response to the recovery of said code.
Claim 12
Dependent Claim
38 words
Playback apparatus as claimed in claim 11 , characterized in that the apparatus is provided with means for setting the recovery means in a mode in which a predetermined data processing indicated by the code recovered is performed.
Claim 13
Dependent Claim
40 words
Playback apparatus as claimed in any one of the claims 10, 11 or 12, characterized in that said transducer comprises a radiation sensitive detector and means for directing a radiation beam on the radiation sensitive detector via the record carrier.
Claim 14
Dependent Claim
68 words
Playback apparatus as claimed in claim 13, characterized by servo control means for controlling the scanning in order to control at least one scanning parameter to a predetermined value on the basis of an error signal derived from a detection signal received from the radiation sensitive detector, the detection means being arranged to detect the presence of variations of said second parameter on the basis said error signal.
Claim 15
Dependent Claim
41 words
Playback apparatus as claimed in claim 14, characterized in that said servo control means comprise tracking control means for controlling the tracking on the basis of a tracking error signal derived from a detection signal received from said radiation sensitive detector.
Claim 16
Dependent Claim
41 words
Playback apparatus as claimed in claim 14, characterized in that the servo control means comprises scanning speed control means, the player apparatus further comprising means for data clock recovery, the detection means comprises means for detecting variations in the clock frequency.
Claim 17
Dependent Claim
61 words
Playback apparatus as claimed in claim 14, characterized that the servo control means comprises focus control means for maintaining a focal point of the scanning beam substantially in the plane in which the optically detectable areas and the intermediate ares are located on the basis of an focus error signal derived from a detection signal received from the radiation sensitive detector.
Claim 18
Dependent Claim
50 words
Record carrier on which information have been recorded in the form of variations of a first physical parameter, said record carrier exhibiting a second variation of a second physical parameter, which differs from said first physical parameter, characterized in that the second variation exhibits a modulation pattern representing a code.
Claim 19
Dependent Claim
50 words
Record carrier as claimed in claim 18 , characterized the information recorded is of a type which is recoverable by means of a predetermined data processing, the code represented by the modulation pattern of the second variation indicating the type of data processing to be used for recovering the information.
Claim 20
Dependent Claim
39 words
Record carrier as claimed in claim 19 or 20, characterized in that said record carrier is of an optical readable type, in which the information has been recorded as a pattern of optically detectable marks arranged along a track.
Claim 21
Dependent Claim
30 words
Record carrier as claimed in claim 20, characterized in that the variations of the second physical parameter being variations in track position in a direction transverse to the track direction.
Claim 22
Dependent Claim
33 words
Record carrier as claimed in claim 20, characterized in that the variations of the second physical parameter being the mean value of the length of the optically detectable areas and the intermediate areas.
Claim 23
Dependent Claim
32 words
Record carrier as claimed in claim 20, characterized that the variation of the second physical parameter being variation in the position of a plane in which said optically detectable marks are situated.
Claim 24
Dependent Claim
66 words
Record carrier as claimed in one of the claims 21,22 or 23, characterized in that the record carrier is a Compact Disc, and that the variations in the second physical parameter result in a variation in the detection signal with a frequency substantially corresponding to 22 kHz in the event that the track is scanned with a scanning speed between 1.2 to 1.4 meter per second.
References Cited (Backward Citations)
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