EP0994470A2
Expired / Lapsed
EP
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Optical recording medium and optical recording/reproducing apparatus
Assignee: Sony Corp
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Filing: 1999-10-13
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Granted: —
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Expires: 2019-10-13
Abstract
Abstract A high-density optical recording medium and an optical recording/reproducing apparatus uses short wavelength blue laser beams to perform recording and reproducing. A 0.6-mm thick light-transmitting layer is formed on an information-recording face of the recording medium. A laser beam having a wavelength λ of 390 nm ≤ λ ≤ 440 nm is transmitted via a lens system having an NA of 0.6 ≤ NA ≤ 0.72, through the light-transmitting layer. The optical recording medium allows recording and/or reproducing to be performed by use of the laser beam. Variation in the thickness of the light-transmitting layer is within a range of ±5.98 λ/(NA) 4 .
Inventors
- 👤 Toshiyuki c/o Sony Corporation Kashiwagi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 03:35
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/2403; G11B7/24065; G11B7/007; G11B7/08; G11B7/09; G11B7/095; G11B7/0956; G11B7/12; G11B7/125; G11B7/127; G11B7/2407; G11B7/24085; G11B7/14
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
74 words
An optical recording medium, comprising: a light-transmitting layer having a thickness of approximately 0.6 mm, which allows
at least one of recording and reproducing to be performed with a laser beam having a
wavelength of 390 nm ≤ λ ≤ 440 nm which is incident to said optical recording medium
through the light-transmitting layer; and wherein the variation in the thickness of the light-transmitting
layer is within a range of ±5.98 λ/(NA) 4 .
Claim 2
Dependent Claim
28 words
The optical recording medium of claim 1, wherein said laser beam is focused by a
lens system having a numerical aperture (NA) of 0.6 ≤ NA ≤ 0.72.
Claim 3
Dependent Claim
29 words
The optical recording medium of claim 2, further comprising a clamp section having a
thickness of at least 1.2 mm, thereby conforming to the format of a standard DVD.
Claim 4
Dependent Claim
32 words
The optical recording medium of claim 2, wherein a skew of the optical recording is
within a range of ± 0.133 λ/(NA) 3 (degrees), where the wavelength λ is measured in
micrometers.
Claim 5
Dependent Claim
48 words
The optical recording medium of claim 2, having at least a part of an information area
in which pit-string data has a track pitch ranging from 0.37 to 0.50 µm, a smallest pit length
is at most 0.27 µm, and a recording density is at most 0.18 µm/bit.
Claim 6
Dependent Claim
50 words
The optical recording medium of claim 2, having at least a part of an information area
in which pit-siring data has a track pitch ranging from 0.37 to 0.50 µm, a smallest pit length
ranges from 0.20 to 0.27 µm, and a recording density ranges from 0.13 to 0.18 µm/bit.
Claim 7
Dependent Claim
35 words
The optical recording medium of claim 2, including in an information recording area a
recordable area in which a track pitch is at most 0.54 µm and a recording density is at most
0.24 µm/bit.
Claim 8
Dependent Claim
39 words
The optical recording medium of claim 2, including, in an information recording area
a record area in which a track pitch ranges from 0.4 to at most 0.54 µm and a recording
density ranges from 0.18 to 0.24 µm/bit.
Claim 9
Dependent Claim
39 words
The optical recording medium of claim 2, including in an information recording area
having a land-and-groove structure a record area in which a track pitch is at most 0.50 µm
and a recording density is at most 0.28 µm/bit.
Claim 10
Dependent Claim
41 words
The optical recording medium of claim 2, including in an information recording area
having a land-and-groove structure a record area in which a truck pitch ranges from 0.37 to
0.50 µm and a recording density ranges from 0.21 to 0.28 µm/bit.
Claim 11
Dependent Claim
84 words
An optical recording/reproducing apparatus employing an optical recording medium
having a light-transmitting layer with a thickness of approximately 0.6 mm and variation in
the thickness within a range of ±5.98 λ/(NA) 4 , said apparatus comprising: an optical unit for performing at least one of recording on and reproducing from said
optical recording medium, said optical unit emitting a laser beam having a wavelength of 390
nm ≤ λ ≤ 440 nm which is incident to said optical recording medium through the light-transmitting
layer.
Claim 12
Dependent Claim
23 words
The optical recording/reproducing apparatus of claim 11, further comprising a lens
system having a numerical aperture (NA) of 0.6 ≤ NA ≤ 0.72.
Claim 13
Dependent Claim
28 words
The optical recording/reproducing apparatus of claim 11, further comprising
compensating means for compensating signal characteristics of reproduced data according to
a detected skew of the optical recording medium.
References Cited (Backward Citations)
No citation records indexed.
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