EP0302666A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Optical information processing apparatus provided with means for holding an optical system in a predetermined position when abnormality occurs to tracking or focusing control
Assignee: Canon Inc
•
Filing: 1988-07-28
•
Granted: —
•
Expires: 2008-07-28
Abstract
Abstract An optical information processing apparatus comprises an optical head (18) having an optical system contained in a frame and effecting at least one of recording and reproduction of information by applying a light beam condensed by the optical system to a recording medium (1), a detector for detecting at least one of a tracking signal and a focusing signal, a controller for moving at least a portion of the optical system in accordance with at least one of the tracking signal and the focusing signal, a detector for detecting the position of the moving portion of the optical system relative to the frame, a position controller for controlling the moving portion so as to be held in a predetermined position, on the basis of the output signal of the position detecting detector, a detector for detecting the abnormality of at least one of the tracking and focusing controls, and a switching device for alternatively operating the tracking and focusing controller and the position controller and rendering the tracking and focusing controller inoperative and operating the position controller when the abnormality of the tracking or focusing controll is detected.
Inventors
- 👤 Shigeto Kanda
- 👤 Hiroto Kitai
- 👤 Etsuo Yamada
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 12:20
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/002; G11B7/0033; G11B19/00; G11B19/02; G11B19/04; G11B7/08; G11B7/09; G11B7/0946
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
195 words
An optical information processing apparatus comprising: an optical head having an optical system contained in a frame and effecting at least one of recording and reproduction of information by applying a light beam condensed by said optical system to a recording medium; means for detecting a tracking signal indicative of the positional deviation between the applied position of said light beam and a track provided on said medium; tracking control means for moving at least a portion of said optical system in accordance with said tracking signal so that said light beam is accurately applied onto the track; means for detecting the position of the moving portion of said optical system relative to said frame; position control means for controlling said moving portion so as to be held in a predetermined position, on the basis of the output signal of said position detecting means; means for detecting the abnormality of said tracking control; and switching means for alternatively operating said tracking control means and said position control means, said switching means being effective to render said tracking control means inoperative and operate said position control means when the abnormality of said tracking control is detected.
Claim 2
Dependent Claim
195 words
An optical information processing apparatus comprising: an optical head having an optical system contained in a frame and effecting at least one of recording and reproduction of information by applying a light beam condensed by said optical system to a recording medium; means for detecting a tracking signal indicative of the positional deviation between the applied position of said light beam and a track provided on said medium; tracking control means for moving at least a portion of said optical system in accordance with said tracking signal so that said light beam is accurately applied onto the track; means for detecting the position of the moving portion of said optical system relative to said frame; position control means for controlling said moving portion so as to be held in a predetermined position, on the basis of the output signal of said position detecting means; means for detecting the abnormality of said tracking control; and switching means for alternatively operating said tracking control means and said position control means, said switching means being effective to render said tracking control means inoperative and operate said position control means when the abnormality of said tracking control is detected.
Claim 3
Dependent Claim
38 words
An optical information processing apparatus according to Claim 1, wherein said tracking control means comprises means for driving the moving portion of said optical system, and a circuit for feeding back said tracking signal to said driving means.
Claim 4
Dependent Claim
72 words
An optical information processing apparatus according to Claim 2, wherein said position control means comprises a circuit for storing therein a signal corresponding to the output of said position detecting means when said moving portion is in said predetermined position, a circuit for differentiating the stored signal and the output signal of said position detecting means, and a circuit for feeding back the output of said differentiating circuit to said driving means.
Claim 5
Dependent Claim
48 words
An optical information processing apparatus according to Claim 3, further comprising means for comparing the output of said differentiating circuit with a predetermined value, and means for moving said optical head in the tracking direction when the output of said differentiating circuit is greater than said predetermined value.
Claim 6
Dependent Claim
22 words
An optical information processing apparatus according to Claim 4, further comprising means for counting the amount of movement of said optical head.
Claim 7
Dependent Claim
31 words
An optical information processing apparatus according to Claim 1, wherein said predetermined position is the position of said moving portion when the operation of said tracking control means has been started.
Claim 8
Dependent Claim
56 words
An optical information processing apparatus according to Claim 1, wherein said position detecting means comprises a light-emitting element mounted on said frame, a reflecting member mounted on said moving means for reflecting the light emitted from said light-emitting element, and a light-receiving element mounted on said frame for detecting the light reflected by said reflecting member.
Claim 9
Dependent Claim
204 words
An optical information processing apparatus comprising: an optical head having an optical system contained in a frame and effecting at least one of recording and reproduction of information by applying a light beam condensed by said optical system to a recording medium; means for detecting a focusing signal indicative of the positional deviation in the direction of the optic axis between the focus position of said light beam and the surface of said medium; focusing control means for moving at least a portion of said optical system in accordance with said focusing signal so that said light beam is accurately focused to the surface of said medium; means for detecting the position of the moving portion of said optical system relative to said frame; position control means for controlling said moving portion so as to be held in a predetermined position, on the basis of the output signal of said position detecting means; means for detecting the abnormality of said focusing control; and switching means for alternatively operating said focusing control means and said position control means, said switching means being effective to render said focusing control means inoperative and operate said position control means when the abnormality of said focusing control is detected.
Claim 10
Dependent Claim
204 words
An optical information processing apparatus comprising: an optical head having an optical system contained in a frame and effecting at least one of recording and reproduction of information by applying a light beam condensed by said optical system to a recording medium; means for detecting a focusing signal indicative of the positional deviation in the direction of the optic axis between the focus position of said light beam and the surface of said medium; focusing control means for moving at least a portion of said optical system in accordance with said focusing signal so that said light beam is accurately focused to the surface of said medium; means for detecting the position of the moving portion of said optical system relative to said frame; position control means for controlling said moving portion so as to be held in a predetermined position, on the basis of the output signal of said position detecting means; means for detecting the abnormality of said focusing control; and switching means for alternatively operating said focusing control means and said position control means, said switching means being effective to render said focusing control means inoperative and operate said position control means when the abnormality of said focusing control is detected.
Claim 11
Dependent Claim
38 words
An optical information processing apparatus according to Claim 8, wherein said focusing control means comprises means for driving the moving portion of said optical system, and a circuit for feeding back said focusing signal to said driving means.
Claim 12
Dependent Claim
72 words
An optical information processing apparatus according to Claim 9, wherein said position control means comprises a circuit for storing therein a signal corresponding to the output of said position detecting means when said moving portion is in said predetermined position, a circuit for differentiating the stored signal and the output signal of said position detecting means, and a circuit for feeding back the output of said differentiating circuit to said driving means.
Claim 13
Dependent Claim
31 words
An optical information processing apparatus according to Claim 8, wherein said predetermined position is the position of said moving portion when the operation of said focusing control means has been strated.
Claim 14
Dependent Claim
44 words
An optical information processing apparatus according to Claim 11, wherein said abnormality detecting means outputs an abnormality detection signal when the difference between said predetermined position and the position of said moving portion detected by said position detecting means is outside a predetermined range.
Claim 15
Dependent Claim
118 words
An optical data storage apparatus comprising an optical head for reading from and/or writing to an optical recording medium, means for scanning the medium and the head relative to each other, a first closed loop control system including the recording medium in the loop for cotrolling of the position of the head and medium relative to each other, a second closed loop control system not including the recording medium in the loop for controlling of the position of the head and the medium relative to each other, means for detecting abnormality of the first closed loop control system and for transferring control from the first to the second closed loop control system in response to such a detection.
Claim 16
Dependent Claim
118 words
An optical data storage apparatus comprising an optical head for reading from and/or writing to an optical recording medium, means for scanning the medium and the head relative to each other, a first closed loop control system including the recording medium in the loop for cotrolling of the position of the head and medium relative to each other, a second closed loop control system not including the recording medium in the loop for controlling of the position of the head and the medium relative to each other, means for detecting abnormality of the first closed loop control system and for transferring control from the first to the second closed loop control system in response to such a detection.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.