EP0298447A2
Expired / Lapsed
EP
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Optical information recording medium
Assignee: Maxell Ltd
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Filing: 1988-07-06
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Granted: —
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Expires: 2008-07-06
Abstract
Abstract There is disclosed an optical information recording medium having a pit array formed in one surface of a substrate (1), individual pits (3) of the pit array being patterned in accordance with a recording signal, wherein an angle (ϑ₁) subtended by the front wall surface (5a) of individual pits and a pit forming plane (1a) of the substrate and an angle (ϑ₁) subtended by the rear wall surface (5b) of the individual pits and the pit forming plane of the substrate are respectively made to be substantially equal to or larger than an angle (ϑ₂) subtended by each of the opposing side wall surface at the central portion of individual pits extending in the light bean scanning direction and the pit forming plane of the substrate. There is also disclosed a method of manufacturing the optical information recording medium by forming pits (3) in a photoresist layer on the surface of a master in a pattern corresponding to a recording signal by irradiating a recording light beam modulated with the recording signal on the photoresist layer, wherein the recording light beam is irradiated at high intensity in synchronism with the rise edge and fall edge of the recording signal and is irradiated in synchronism with an intermediate portion between the rise and fall edges at lower intensity than the high intensity for the irradiation of light beam in synchronism with the rise and fall edges.
Inventors
- 👤 Tamotsu Iida
- 👤 Atsuki Hirose
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 15:52
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/26; G11B7/2407; G11B7/24085; G11B7/002; G11B7/0033; G11B7/261
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
127 words
An optical information recording medium having a pit array (2) formed in one surface of a substrate (1), individual pits (3) of said pit array being patterned in accordance with a recording signal (35), wherein an angle (ϑ₁) subtended by the front wall surface (5a) of individual pits and a pit forming plane (1a) of said substrate and an angle (ϑ₁) subtended by the rear wall surface (5b) of the individual pits and said pit forming plane of said substrate are respectively made to be substantially equal to or larger than an angle (ϑ₂) subtended by each of the opposing side wall surfaces (5c) at the central portion (3c) of individual pits extending in the light beam scanning direction and said pit forming plane of said substrate.
Claim 2
Dependent Claim
127 words
An optical information recording medium having a pit array (2) formed in one surface of a substrate (1), individual pits (3) of said pit array being patterned in accordance with a recording signal (35), wherein an angle (ϑ₁) subtended by the front wall surface (5a) of individual pits and a pit forming plane (1a) of said substrate and an angle (ϑ₁) subtended by the rear wall surface (5b) of the individual pits and said pit forming plane of said substrate are respectively made to be substantially equal to or larger than an angle (ϑ₂) subtended by each of the opposing side wall surfaces (5c) at the central portion (3c) of individual pits extending in the light beam scanning direction and said pit forming plane of said substrate.
Claim 3
Dependent Claim
48 words
An optical information recording medium according to Claim 1 wherein when observing said substrate in its plan view, the width of the front and rear edges of a pit is larger than the width of the central portion of the pit extending in the light beam scanning direction.
Claim 4
Dependent Claim
38 words
An optical information recording medium according to Claim 1 wherein when observing said substrate in its plan view, the width of a pit is substantially uniform throughout the front edge, central portion and rear edge of the pit.
Claim 5
Dependent Claim
28 words
An optical information recording medium according to Claim 1 wherein a pit has the pit length which is larger than the diameter (d) of a reading light beam.
Claim 6
Dependent Claim
73 words
An information recording medium according to Claim 4 wherein the width (W₁) of the front and rear edges (3a, 3b) on the opening plane of the pit having the pit length smaller than the reading light spot diameter (d) is larger than the width (W₁) of the front and rear edges (3a, 3b) on the opening plane of a different pit having the pit length larger than the reading light spot diameter (d).
Claim 7
Dependent Claim
74 words
An optical information recording medium according to Claim 4 wherein the width (W₂) of the front and rear edges (4a, 4b) on the bottom plane of the pit having the pit length smaller than the reading light spot diameter (d) is larger than the width (W₂) of the front and rear edges (4a, 4b) on the bottom plane of a different pit having the pit length larger than the reading light spot diameter (d).
Claim 8
Dependent Claim
68 words
An optical information recording medium according to Claim 4 wherein the width (W₃) of the central portion (3c) on the opening plan of the pit having the pit length smaller than the reading light spot diameter (d) is larger than the width (W₃) of the central portion (3c) on the opening plane of a different pit having the pit length larger than the reading light spot diameter (d).
Claim 9
Dependent Claim
68 words
An optical information recording medium according to Claim 4 wherein the width (W₃) of the central portion (3c) on the bottom plane of the pit having the pit length smaller than the reading light spot diameter (d) is larger than the width (W₃) of the central portion (3c) on the bottom plane of a different pit having the pit length larger than the reading light spot diameter (d).
Claim 10
Dependent Claim
74 words
An optical information recording medium according to Claim 4 wherein an area by which the pit having the pit length smaller than the reading light spot diameter occupies the reading light spot on the opening plane of the pit is substantially equal to an area by which a different pit having the pit length larger than the reading light spot diameter occupies the reading light spot on the opening plane of the different pit.
Claim 11
Dependent Claim
74 words
An optical information recording medium according to Claim 4 wherein an area by which the pit having the pit length smaller than the reading light spot diameter occupies the reading light spot on the bottom plane of the pit is substantially equal to an area by which a different pit having the pit length larger than the reading light spot diameter occupies the reading light spot on the bottom plane of the different pit.
Claim 12
Dependent Claim
28 words
An optical information recording medium according to Claim 1 wherein the pit array has pits oriented longitudinally in a direction perpendicular to the reading light beam scanning direction.
Claim 13
Independent Claim
110 words
A method of manufacturing an optical information recording medium by forming pits (3) in a photoresist layer on the surface of a master (10) in a pattern corresponding to a recording signal (35) by irradiating a recording light beam (36) modulated with the recording signal on the photoresist layer, wherein the recording light beam is irradiated at high intensity in synchronism with the rise edge (35a) and fall edge (35b) of the recording signal and is irradiated in synchronism with an intermediate portion between the rise and fall edges at lower intensity than the high intensity for the irradiation of light beam in synchronism with the rise and fall edges.
Claim 14
Independent Claim
110 words
A method of manufacturing an optical information recording medium by forming pits (3) in a photoresist layer on the surface of a master (10) in a pattern corresponding to a recording signal (35) by irradiating a recording light beam (36) modulated with the recording signal on the photoresist layer, wherein the recording light beam is irradiated at high intensity in synchronism with the rise edge (35a) and fall edge (35b) of the recording signal and is irradiated in synchronism with an intermediate portion between the rise and fall edges at lower intensity than the high intensity for the irradiation of light beam in synchronism with the rise and fall edges.
Claim 15
Dependent Claim
64 words
A method for manufacture of an optical information recording medium according to Claim 12 wherein the recording light beam is irradiated for formation of a pit (3) having the pit length smaller than the reading light spot at higher intensity than that of the recording light beam irradiated for formation of a different pit having the pit length larger than the reading light spot.
Claim 16
Dependent Claim
41 words
A method for manufacture of an optical information recording medium according to Claim 12 wherein a light beam having the spot shape of an ellipse extending in a direction perpendicular to the scanning direction is used as the recording light beam.
Claim 17
Dependent Claim
111 words
An optical information recording medium having a pit array (2) formed in one surface of a substrate (1), individual pits (3) of said pit array being patterned in accordance with a recording signal (35), wherein the radius of an arc forming the front edge of the individual pits and the radius of an arc forming the area edge of the individual pits are respectively mode to be substantially equal to the distance between the center line in the light beam scanning direction of the individual pits and the line parallel to the center line and contouring the edge of each of the opposing side wall surfaces (5c) of the individual pits.
Claim 18
Dependent Claim
111 words
An optical information recording medium having a pit array (2) formed in one surface of a substrate (1), individual pits (3) of said pit array being patterned in accordance with a recording signal (35), wherein the radius of an arc forming the front edge of the individual pits and the radius of an arc forming the area edge of the individual pits are respectively mode to be substantially equal to the distance between the center line in the light beam scanning direction of the individual pits and the line parallel to the center line and contouring the edge of each of the opposing side wall surfaces (5c) of the individual pits.
References Cited (Backward Citations)
No citation records indexed.
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