EP0639830A1
Expired / Lapsed
EP
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Optical recording apparatus
Assignee: Panasonic Holdings Corp
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Filing: 1990-07-25
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Granted: —
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Expires: 2010-07-25
Abstract
Abstract An optical recording apparatus comprises optical recording mediums each of which comprises a single plate substrate and recording layers which are formed on both sides of the substrate and available for recording and reproduction or for recording, erasing and reproduction with irradiation of laser beams, both surfaces of the recording medium being available for the simultaneous access, and floating type optical thin heads which are provided at every side of the recording mediums and float from the respective surfaces of the recording mediums with maintaining specific distances therefrom for irradiating laser beams onto the recording mediums when the recording mediums are rotated. Combination of these optical recording mediums and optical heads makes it possible to stack plural pairs of them within a thin space, thus improving the on-line capacity of the optical recording apparatus to a great extent.
Inventors
- 👤 Noboru Yamada
- 👤 Isao Satoh
- 👤 Sadao Mizuno
- 👤 Yasuhiro Gotoh
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 18:31
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/26; G11B7/241; G11B7/252; G11B7/254; G11B7/004; G11B7/0045; G11B7/00454; G11B7/12; G11B7/122; G11B7/14; G11B7/242; G11B7/243; G11B2007/24302; G11B2007/24312; G11B2007/24314; G11B2007/24316; G11B2007/25408; G11B2007/25417; G11B7/257; G11B2007/25705; G11B2007/25706; G11B2007/2571; G11B2007/25715; G11B2007/25716; G11B7/258; G11B7/2595
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
142 words
An optical recording apparatus comprising at least one recording medium (1) having a single plate substrate (8) and a recording film (10) thereon capable of producing optically detectable changes, between plural states, due to laser irradiation; means (4) for rotating said recording medium (1); and at least one floating-type optical head (2), which floats on a respective surface of said recording medium (1) so as to maintain a specific distance therefrom, whereby a laser beam irradiates said recording medium (1) when it is rotated, in a fixed direction, by said rotating means (4), characterised in that a plurality (6) of recording media is provided, the recording film (1) being provided on both sides of each recording medium; and that an optically transparent protective layer having a thickness of several hundreds µm at most is formed on the surface of each recording film.
Claim 2
Dependent Claim
17 words
Apparatus according to Claim 1, wherein said plurality of recording media (1) are arranged in a stack.
Claim 3
Dependent Claim
30 words
Apparatus according to Claim 1 or 2 further including an air tight box (3) for housing said plurality of recording media, said rotating means (4) and said optical heads (2).
Claim 4
Dependent Claim
76 words
Apparatus according to any of the preceding Claims wherein the surface of each said substrate has a continuous groove, or a row of signal pits arranged along a spiral line to guide said laser beam to a desired position, directions of the spiral lines on upper and lower surfaces of the plurality of recording media being the same respectively, and directions of the spiral lines on said upper and lower surfaces being opposite from each other.
Claim 5
Dependent Claim
40 words
Apparatus according to any of the preceding Claims wherein said rotating means (4) provides a constant relative linear velocity to the plurality of recording media with respect to said optical heads (2), regardless of the positions of said optical heads.
Claim 6
Dependent Claim
42 words
Apparatus according to any of the preceding Claims wherein each of said optical heads (2) comprises a slider (12), an objective lens (13), and a deflection prism or mirror (14), which are all made of the same material in a monoblock body.
Claim 7
Dependent Claim
19 words
Apparatus according to Claim 6, wherein numerical aperture of said objective lens is equal to, or larger than 0.6.
Claim 8
Dependent Claim
23 words
Apparatus according to Claim 6, wherein the surfaces of said sliders (12), facing the recording media, are coated with DLC thin films (24).
Claim 9
Dependent Claim
16 words
Apparatus according to any preceding Claim, wherein a dielectric layer is formed on said recording film.
Claim 10
Dependent Claim
21 words
Apparatus according to any preceding Claim, wherein said optical recording medium (1) has reflective layers directly formed on said substrate (8).
Claim 11
Dependent Claim
36 words
Apparatus according to any preceding claim, wherein each of said optical heads produces a single laser beam as means for information rewriting, and having means for overwriting by modulating the irradiation power of said laser beam.
Claim 12
Dependent Claim
17 words
Apparatus according to any preceding claim, wherein the protective layer is composed of a DLC thin film.
Claim 13
Dependent Claim
21 words
Apparatus according to Claim 1, wherein the optically transparent protective layer has a thickness which is not smaller than 50 µm.
Claim 14
Dependent Claim
35 words
Apparatus according to Claim 1, wherein the optically transparent protective layer is formed by means of vacuum evaporation, CVD, or sputtering and has a thickness in the range from 0.1 µm to about 100 µm.
Claim 15
Dependent Claim
21 words
Apparatus according to Claim 15, wherein a layer of resin is formed on the optically transparent protective layer by spin coating.
Claim 16
Dependent Claim
89 words
Apparatus according to Claim 15, wherein the thickness of the optically transparent protective layer and the layer of resin is set at hundreds µm at the most, when an objective lens on the floating head (2) has an effective diameter of about 1 mm and an N.A. of about 0.5 to 0.9; and the thickness of the optically transparent protective layer is equal to, or less than 100 µm, or more preferably equal to, or smaller than 10 µm with an increase in the N.A. of the objective lens.
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