EP0326343A2
Expired / Lapsed
EP
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Optical information recording apparatus
Assignee: Canon Inc
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Filing: 1989-01-25
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Granted: —
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Expires: 2009-01-25
Abstract
Abstract An optical information recording apparatus comprises an optical head for recording information by irradiating a recording medium with a light beam, a tracking servo circuit for correcting an error in position between the irradiating position of the light beam and a track formed on said medium, a circuit for detecting abnormality in the tracking servo, and a control circuit for reducing the power of the light beam irradiating the medium to a non-zero level not enough for recording, in response to a detection signal from the abnormality detecting circuit.
Inventors
- 👤 Shigeto Kanda
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 23:28
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/0946
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
89 words
An optical information recording apparatus comprising: an optical head for recording information by irradiating a recording medium with a light beam; a tracking servo circuit for correcting an error in position between the irradiating position of said light beam, and a track formed on said medium; a circuit for detecting abnormality in said tracking servo; and a control circuit for reducing the power of the light beam irradiating said medium to a non-zero level not enough for recording, in response to a detection signal from said abnormality detecting circuit.
Claim 2
Dependent Claim
89 words
An optical information recording apparatus comprising: an optical head for recording information by irradiating a recording medium with a light beam; a tracking servo circuit for correcting an error in position between the irradiating position of said light beam, and a track formed on said medium; a circuit for detecting abnormality in said tracking servo; and a control circuit for reducing the power of the light beam irradiating said medium to a non-zero level not enough for recording, in response to a detection signal from said abnormality detecting circuit.
Claim 3
Dependent Claim
64 words
An optical information recording apparatus according to claim 1, wherein said optical head comprises a lens for condensing said light beam onto the medium and rendered movable for the purpose of tracking in a direction perpendicular to the optical axis thereof; and said abnormality detecting circuit is adapted to release a detection signal when the moving velocity of said lens exceeds a predetermined value.
Claim 4
Dependent Claim
59 words
An optical information recording apparatus according to claim 2, wherein said abnormality detecting circuit comprises a displacement detector for detecting the displacement of said lens, a velocity detecting circuit for detecting the velocity of said lens from the output of said displacement detector, and a comparator for comparing the output of said velocity detecting circuit with a predetermined level.
Claim 5
Dependent Claim
65 words
An optical information recording apparatus according to claim 1, wherein said abnormality detecting circuit comprises a displacement detector for detecting the displacement of said lens, a high-pass filter for extracting, from the output of said displacement detector, components of a predetermined frequency or higher, and comparator means for releasing a detection signal when the output of said high-pass filter becomes out of a predetermined range.
Claim 6
Dependent Claim
51 words
An optical information recording apparatus according to claim 4, wherein said comparator means comprises two comparators for respectively comparing the output of said high-pass filter with an upper limit value and a lower limit value, and an OR circuit for releasing a logic sum signal of the outputs of said comparators.
Claim 7
Dependent Claim
57 words
An optical information recording apparatus according to claim 1, wherein said abnormality detecting circuit comprises a displacement detector for detecting the displacement of said lens, a differentiating circuit for differentiating the output of said displacement detector, and comparator means for releasing a detection signal when the output of said differentiating circuit becomes out of a predetermined range.
Claim 8
Dependent Claim
51 words
An optical information recording apparatus according to claim 6, wherein said comparator means comprises two comparators for respectively comparing the output of said differentiating circuit with an upper limit value and a lower limit value, and an OR circuit for releasing a logic sum signal of the outputs of said comparators.
Claim 9
Dependent Claim
70 words
An optical information recording apparatus according to claim 1, wherein said abnormality detecting circuit comprises a displacement detector for detecting the displacement of said lens, a low-pass filter for transmitting a part of the output of said displacement detector, and comparator means for releasing a detection signal when the difference of the outputs transmitted by said low-pass filter and the original output of the displacement detector exceeds a predetermined value.
Claim 10
Dependent Claim
83 words
An optical information recording apparatus according to claim 8, wherein said comparator means comprises two voltage sources for adding first or second predetermined values to the output transmitted by said low-pass filter; first and second comparators respectively receiving said output added at an inverted input terminal and an uninverted input terminal thereof, and further receiving the original output of said displacement detector at the remaining input terminals; and an OR circuit for releasing a logic sum signal of the outputs of said comparators.
Claim 11
Dependent Claim
27 words
An optical information recording apparatus according to claim 1, wherein said control circuit comprises a system controller for controlling a driving circuit for driving said light source.
Claim 12
Dependent Claim
75 words
An optical information recording apparatus in which information is recorded by applying light from a light beam to a recording medium, the apparatus responding to the detection of an abnormal condition such that said recording should be halted, characterised in that the said response of the apparatus is to reduce the power of the light beam to a non-zero level such that the light applied to the recording medium has insufficient power to cause recording.
Claim 13
Dependent Claim
75 words
An optical information recording apparatus in which information is recorded by applying light from a light beam to a recording medium, the apparatus responding to the detection of an abnormal condition such that said recording should be halted, characterised in that the said response of the apparatus is to reduce the power of the light beam to a non-zero level such that the light applied to the recording medium has insufficient power to cause recording.
References Cited (Backward Citations)
No citation records indexed.
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