EP0411525A2
Expired / Lapsed
EP
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A method of making optical disk master and an optical disk
Assignee: Hitachi Ltd
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Filing: 1990-07-30
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Granted: —
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Expires: 2010-07-30
Abstract
Abstract An optical disk master (19) having a diffraction structure including guide grooves (8) and small pre- pits (9) of a width narrower than a diffraction limit determined by a wavelength of light used is produced by preparing a photoresist layer (21) subjected to anti-dissolution surface treatment, narrowing the spot diameter of a zero-th diffracted beam irradiated on the photoresist layer by means of a super resolution optics (22), and effecting high contrast development to leave behind, as it is, a portion of the photoresist layer exposed to adverse higher order diffracted beams caused by super resolution. An optical disk (45) produced from the master has a diffraction structure including tracks and/or pre-pits formed along a spiral track or concentric tracks (7) and having a width narrower than a diffraction limit determined by a wavelength of light used in the course of formation of the diffraction structure.
Inventors
- 👤 Masaru Ito
- 👤 Masumi Fujita
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 13:25
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/26; G11B7/261; G03; G03F; G03F7/00; G03F7/26; G03F7/70; G03F7/70216; G03F7/70241; G03F7/70308; G11B7/004; G11B7/2407; G11B7/24085; G11B7/12; G11B7/135; G11B7/1372; G11B2007/13727
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
86 words
A method of making an optical disk master comprising the steps of: preparing a disk (20) deposited with a photoresist layer (21) having its surface (30) subjected to an anti-dissolution treatment; focusing a light beam intensity-modulated by a signal to be recorded on said photoresist layer by means of a super resolution optical system (22); and moving said disk and said light beam relative to each other to form, in said photoresist layer, a latent image pattern (32, 33) corresponding to said signal to be recorded.
Claim 2
Independent Claim
86 words
A method of making an optical disk master comprising the steps of: preparing a disk (20) deposited with a photoresist layer (21) having its surface (30) subjected to an anti-dissolution treatment; focusing a light beam intensity-modulated by a signal to be recorded on said photoresist layer by means of a super resolution optical system (22); and moving said disk and said light beam relative to each other to form, in said photoresist layer, a latent image pattern (32, 33) corresponding to said signal to be recorded.
Claim 3
Dependent Claim
55 words
An optical disk master making method according to Claim 1 wherein said super resolution optical system includes an optical filter (13, 14) for modulating said light beam in at least one of amplitude distribution and phase distribution, and a lens (17) for focusing the light beam passing through said optical filter on said photoresist layer.
Claim 4
Dependent Claim
69 words
An optical disk master making method according to Claim 2 wherein said optical filter has at its central portion a linear modulation area (27, 29) having a width narrower than a cross-sectional area of the light beam incident to said optical filter so that an optical spot (31) to be focused on said photoresist layer may be elongated in a direction parallel to a track on the photoresist layer.
Claim 5
Dependent Claim
40 words
An optical disk master making method according to Claim 2 wherein said optical filter includes at its central portion a circular modulation area (26) having a cross-sectional area smaller than that of the light beam incident to said optical filter.
Claim 6
Dependent Claim
32 words
An optical disk master making method according to any one of Claims 2 to 4 wherein said optical system includes means (15) for deflecting the light beam passing through said optical filter.
Claim 7
Dependent Claim
51 words
An optical disk master making method according to Claim 2 wherein used said optical filter includes a plurality of optical filters (13, 14; 13 , 14 having differently shaped modulation areas, and a plurality of light beams passing through said plurality of filters are incident to said lens at different angles.
Claim 8
Dependent Claim
41 words
An optical disk master making method according to any one of Claims 1 to 6 wherein said anti- dissolution treatment includes the steps of immersing said photoresist layer still remaining unexposed in a developer, washing it with water and drying it.
Claim 9
Dependent Claim
29 words
An optical disk having a replica disk (40) produced from the optical disk master made by the making method as recited in any one of Claims 1 to 7.
Claim 10
Dependent Claim
50 words
An optical disk comprising: a disk (40) having one major surface in which a diffraction structure having a width falling within a range of from 0.2 to 0.4 I lm is formed along a spiral track or concentric tracks (7); and a recording film (44) formed on said major surface.
Claim 11
Dependent Claim
50 words
An optical disk comprising: a disk (40) having one major surface in which a diffraction structure having a width falling within a range of from 0.2 to 0.4 I lm is formed along a spiral track or concentric tracks (7); and a recording film (44) formed on said major surface.
Claim 12
Dependent Claim
25 words
An optical disk according to Claim 9 wherein the boundary area between said diffraction structure and said major surface is not rounded but is sharpened.
Claim 13
Dependent Claim
26 words
An optical disk according to Claim 9 wherein said diffraction structure includes a guide groove (8) for guiding the light beam irradiated on said optical disk.
Claim 14
Dependent Claim
21 words
An optical disk according to Claim 9 wherein said diffraction structure includes pre-pits representative of a record of a pre-formatted signal.
Claim 15
Dependent Claim
44 words
A double sided recording optical disk comprising two of the optical disks as recited in any one of Claims 8 to 12, said two optical disks being put together through an adhesive layer (47) such that their recording films (44) oppose to each other.
Claim 16
Dependent Claim
130 words
An optical disk master cutting machine comprising: a super resolution optical system for generating a light beam intensity-modulated by a signal to be recorded (22); and drive means for relatively moving said super resolution optical system and a master disk (19) having on its surface a photoresist layer (21) to form, in said photoresist layer, a latent image pattern corresponding to said signal to be recorded; said super resolution optical system including light source means (11, 12) for emitting a light beam representative of a pre-formatted signal, an optical filter (13, 14) for modulating the light beam in at least one of amplitude distribution and phase distribution, and a recording lens (17) for focusing the light beam passing through said optical filter on said photoresist layer of said master disk.
Claim 17
Dependent Claim
130 words
An optical disk master cutting machine comprising: a super resolution optical system for generating a light beam intensity-modulated by a signal to be recorded (22); and drive means for relatively moving said super resolution optical system and a master disk (19) having on its surface a photoresist layer (21) to form, in said photoresist layer, a latent image pattern corresponding to said signal to be recorded; said super resolution optical system including light source means (11, 12) for emitting a light beam representative of a pre-formatted signal, an optical filter (13, 14) for modulating the light beam in at least one of amplitude distribution and phase distribution, and a recording lens (17) for focusing the light beam passing through said optical filter on said photoresist layer of said master disk.
References Cited (Backward Citations)
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