EP0116467A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Optical disc players
Assignee: Sony Corp
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Filing: 1984-02-09
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Granted: —
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Expires: 2004-02-09
Abstract
Abstract An optical disc player is operative to cause a light beam to impinge through an object lens (7) on a recording surface of a record disc (1) and to receive a reflected light beam passing through the object lens (7) from the recording surface by photodetecting means (10), so as to reproduce an information signal recorded on the disc (1). A first signal varying in response to positional movements of the object lens (7) and a second signal varying in response to variations of a position on the photodetecting means (10) where the reflected light beam is received and which result from the positional movements of the object lens (7) are mixed with each other to produce a mixed signal with which an inclination of an optical axis of the light beam incident upon the recording surface with respect to a normal line at a location where the light beam impinges on the recording surface is detected.
Inventors
- 👤 Hajime C/O Patent Division Yano
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 23:18
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/095; G11B7/0956
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
261 words
An optical disc player for reproducing optically an information signal recorded in a record track formed on a recording surface of a disc (1), the optical disc player comprising; light source means (2) for generating a light beam; optical means (11) including an object lens (7) for directing said light beam to the recording surface of the disc (1) and allowing a reflected light beam from the recording surface of the disc (1) to pass through the optical means; and photodetecting means (10) for receiving said reflected light beam from said object lens (7) to produce in response to the received light beam a detected output from which a reproduced information signal can be obtained; characterized by: control means comprising first detecting means (21) for producing a first signal varying in response to variations of a position where said light beam impinges on the recording surface of the disc (1), second detecting means (12) for producing from the detected output of said photodetecting means ; (10) a second signal varying in response to variations of the position on said photodetecting means (10) where said reflected light beam is received, and mixing means (19) for mixing said first and second signals so as to cancel a component of said second signal which results from the variations of the position where said light beam impinges on the recording surface of the disc (1) and thereby to produce a third signal with which a skew occuring in connection with said light beam incident upon the recording surface of the disc (1) can be detected.
Claim 2
Dependent Claim
261 words
An optical disc player for reproducing optically an information signal recorded in a record track formed on a recording surface of a disc (1), the optical disc player comprising; light source means (2) for generating a light beam; optical means (11) including an object lens (7) for directing said light beam to the recording surface of the disc (1) and allowing a reflected light beam from the recording surface of the disc (1) to pass through the optical means; and photodetecting means (10) for receiving said reflected light beam from said object lens (7) to produce in response to the received light beam a detected output from which a reproduced information signal can be obtained; characterized by: control means comprising first detecting means (21) for producing a first signal varying in response to variations of a position where said light beam impinges on the recording surface of the disc (1), second detecting means (12) for producing from the detected output of said photodetecting means ; (10) a second signal varying in response to variations of the position on said photodetecting means (10) where said reflected light beam is received, and mixing means (19) for mixing said first and second signals so as to cancel a component of said second signal which results from the variations of the position where said light beam impinges on the recording surface of the disc (1) and thereby to produce a third signal with which a skew occuring in connection with said light beam incident upon the recording surface of the disc (1) can be detected.
Claim 3
Dependent Claim
31 words
An optical disc player according to claim 1 wherein said first detecting means (21) comprises positional shift detecting means (21) for detecting shift in the position of said object lens (7).
Claim 4
Dependent Claim
46 words
An optical disc player according to claim 2 wherein said positional shift detecting means (21) comprises a circuit for generating a voltage varying in response to variations in a driving voltage supplied to driving means (8) for causing said object lens (7) to have positional shift.
Claim 5
Dependent Claim
73 words
An optical disc player according to claim 1 wherein said photodetect ing means (10) comprises first, second, third and fourth photodetecting elements (PD J , PD 2 , PD3, PD 4 ) and a subtracting circuit (29) for deriving the difference between the sum of outputs of said first and second photodetecting elements (PD 1 , PD2) and the sum of outputs of said third and fourth photodetecting elements (PD3, PD 4 ).
Claim 6
Dependent Claim
42 words
An optical disc player according to claim 1 wherein said first detecting means (21) comprises signal generating means for generating said first signal when said object lens (7) is moved in a direction transverse to the record track on the disc (1).
Claim 7
Dependent Claim
42 words
An optical disc player according to claim 5 wherein said signal generating means comprises means for detecting the movement of said object lens (7) in the direction transverse to the record track on the disc (1) and producing an additional detected output.
Claim 8
Dependent Claim
62 words
An optical disc player according to claim 1 wherein said second detecting means (12) comprises signal generating means for generating said second signal when the position on said photodetecting means (10) where said reflected light beam is received is shifted as a result of movement of said object lens (7) in a direction transverse to the record track on the disc (1).
Claim 9
Dependent Claim
62 words
An optical disc player according to claim 7 wherein said signal generating means comprises means for detecting the shift of the position on said photodetecting means (10) where said reflected light beam is received which results from the movement of said object lens (7) in the direction transverse to the record track on the disc (1) and producing an additional detected output.
References Cited (Backward Citations)
No citation records indexed.
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