Patent EP0083475A1 successfully refreshed from Google Patents.
EP0083475A1
Expired / Lapsed
EP
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Optical data recording and reproducing apparatus
Assignee: Panasonic Holdings Corp
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Filing: 1982-12-03
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Granted: —
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Expires: 2002-12-03
Abstract
Abstract An apparatus for recording and reproducing digital data in an optical recording disc (8) having a plurality of sector region which has a greatly improved reliability of the recording quality is disclosed. An optical recording disc generally has a dropout which decreases the envelope of a recording or reproduced signal and causes a demodulation error. Before recording, each sector is checked for a dropout, and any sector containing a dropout harmful to the recording signal is skipped in recording, thereby greatly reducing a demodulation error. The apparatus further comprises a device for accurately detecting any form of dropout adversely affecting the recording signal.
Inventors
- 👤 Kenji Koishi
- 👤 Tomio Yoshida
- 👤 Isao Satoh
- 👤 Shunji Ohara
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 02:20
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/0948; G11B19/00; G11B19/02; G11B19/04; G11B20/00; G11B20/10; G11B20/18; G11B27/00; G11B27/10; G11B27/19; G11B27/28; G11B27/30; G11B27/3027; G11B27/36; G11B7/004; G11B7/0045
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
292 words
An optical data recording and reproducing apparatus for recording digital data in an optical recording disc (8) having an address signal region (N), a sector address region (n l , n 2 , n 3 , ....., n m ) and a data recording region (ℓ 1 , Q 2 , ℓ 3 , ....., ℓ m ), and for reproducing the digital data from said optical recording disc, comprising a light source (1), light illumination means (2, 3, 4, 5) for condensing the output light source to a very small diameter and for illuminating said optical recording disc, recording-reproducing means (10, 11) for recording and reproducing said digital data by the recording light and reproduced light of said light illumination means, recording-prohibited sector detector means (113, 114, 115) for causing said reproduced light to be radiated on said optical recording disc immediately before the recording of said digital data thereby to check each sector of the data recording region to be recorded with said digital data, said recording-prohibited sector detector means producing an output in the presence of a sector where the recording is prohibited, recording-prohibited sector memory means (118) for storing the address of the recording-prohibited sector in response to the output of said recording-prohibited sector detector means at least until said digital data begins to be recorded in said optical recording disc, comparator means (62) for comparing the sector address of said recording-prohibited sector stored in said recording-prohibited sector memory means wity the sector address read constantly from said optical recording disc, and recording signal output prohibiting means for prohibiting the output of the recording signal from said light source in response to a coincidence output of said comparator means and holding said recording signal until the next sector.
Claim 2
Dependent Claim
292 words
An optical data recording and reproducing apparatus for recording digital data in an optical recording disc (8) having an address signal region (N), a sector address region (n l , n 2 , n 3 , ....., n m ) and a data recording region (ℓ 1 , Q 2 , ℓ 3 , ....., ℓ m ), and for reproducing the digital data from said optical recording disc, comprising a light source (1), light illumination means (2, 3, 4, 5) for condensing the output light source to a very small diameter and for illuminating said optical recording disc, recording-reproducing means (10, 11) for recording and reproducing said digital data by the recording light and reproduced light of said light illumination means, recording-prohibited sector detector means (113, 114, 115) for causing said reproduced light to be radiated on said optical recording disc immediately before the recording of said digital data thereby to check each sector of the data recording region to be recorded with said digital data, said recording-prohibited sector detector means producing an output in the presence of a sector where the recording is prohibited, recording-prohibited sector memory means (118) for storing the address of the recording-prohibited sector in response to the output of said recording-prohibited sector detector means at least until said digital data begins to be recorded in said optical recording disc, comparator means (62) for comparing the sector address of said recording-prohibited sector stored in said recording-prohibited sector memory means wity the sector address read constantly from said optical recording disc, and recording signal output prohibiting means for prohibiting the output of the recording signal from said light source in response to a coincidence output of said comparator means and holding said recording signal until the next sector.
Claim 3
Dependent Claim
47 words
An optical data recording and reproducing apparatus according to Claim 1, wherein the length of the data recording region where a recording-prohibited sector is detected each time is not shorter than the length of the data recording region included in one revolution of said optical recording disc.
Claim 4
Dependent Claim
42 words
An optical data recording and reproducing apparatus according to Claim 1, wherein the length of the data recording region where a recording-prohibited sector is detected each time is determined by the length of the digital data to be recorded the next time.
Claim 5
Dependent Claim
57 words
An optical data recording and reproducing apparatus according to Claim 1, wherein said recording-prohibited sector detector means provides dropout checking-inspecting means (113, 114) for scanning said data recording region by a reproduced light beam, detecting a dropout signal, if any, checking the condition of the dropout, and producing an output in the presence of an unsatisfactory sector.
Claim 6
Dependent Claim
61 words
An optical data recording and reproducing apparatus according to Claim 4, wherein said dropout detector means measures the duration of a dropout, the number of dropouts in a sector and the frequency of generation thereof, and determines whether the sector should be prohibited from recording on the basis of the possibility of correction of the reproduced signal at error-correcting means (117).
Claim 7
Dependent Claim
56 words
An optical data recording and reproducing apparatus according to Claim 1, wherein said recording-prohibited sector detector means is comprised of envelope detector means (115) for scanning said data recording region with a reproduced light, determining whether the envelope of a recorded signal is contained therein, and producing an output in the presence of a recorded sector.
Claim 8
Dependent Claim
78 words
An optical data recording and reproducing apparatus according to Claim 4, further comprising a first clamp circuit (13) for clamping said dropout signal and a second clamp circuit (16) opposite in polarity to said first clamp circuit, wherein a dropout in said data recording region is detected by means (14, 17) for digitizing the output of said first and second clamp circuits by a predetermined threshold voltage and means (21) for counting the duration of said digitized output.
Claim 9
Dependent Claim
119 words
An optical data recording and reproducing apparatus according to Claim 1, further comprising means (19) for delaying the first digitized output of said first clamp circuit and the second digitized output of said second clamp circuit, and means (30, 31) for detecting the superposition between the trailing edge of the delayed output of said first digitized output and said second digitized output and the superposition between the trailing edge of the delayed output of said second digitized output and said first digitized output, thereby dampening the spurious output generated by discharge of a clamp capacitor (22) at the trailing edge of the dropout occurring in the forward direction of the clamp element of said first and second clamp circuits.
Claim 10
Dependent Claim
72 words
An optical data recording and reproducing apparatus according to Claim 4, wherein said dropout signal is such that selected one of the light relfected on and transmitted through said optical recording disc is received by a light detector (6) having at least two split planes, and the data recording region is checked for a dropout from at least one of the difference and sum signals of the output of said light detector.
Claim 11
Dependent Claim
77 words
An optical data recording and reproducing apparatus according to Claim 9, wherein the far field pattern of selected one of the light reflected on and the light transmitted through said optical recording disc is received by a light detector (6) having a split plane perpendicular to selected one of concentric and spiral tracks, said apparatus further comprising means (114) for checking said data recording region for a dropout from the difference signal produced from said light detector.
Claim 12
Dependent Claim
77 words
An optical data recording and reproducing apparatus according to Claim 9, wherein the far field pattern of selected one of the light reflected on and the light transmitted through said optical recording disc is received by a light detector (6) having a split plane parallel to selected one of concentric and spiral tracks, said apparatus further comprising means (114) for checking said data recording region for a dropout from the difference signal produced from said light detector.
Claim 13
Dependent Claim
58 words
An optical data recording and reproducing apparatus according to of Claims 9, further comprising focus control means (143) for constantly forming an image of the minute spot light on the optical recording disc, and means (114) for checking said data recording region for a dropout from a focuss error signal detected from said light detector for focus control.
References Cited (Backward Citations)
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