US5745475A
Expired / Lapsed
US
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Optical information recording medium
Assignee: Panasonic Holdings Corp
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Filing: 1997-06-27
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Granted: 1998-04-28
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Expires: 2017-06-27
Abstract
Abstract An optical information recording medium includes: a substrate including a groove having a concave shape and a land having a convex shape adjacent to the groove; and a recording layer on the substrate, wherein the recording layer consists of a material which changes between a first state and a second state whose optical property is different from that of the first state, a first portion of the optical information recording medium including a portion in the first state of the recording layer having a first reflectance, and a second portion of the optical information recording medium including a region in the second state of the recording layer having a second reflectance which is different from the first reflectance, whereby information is recorded onto the groove and the land, and wherein a ratio of the first reflectance to the second reflectance, a phase of reflected light from the first portion and a phase of reflected light from the second portion are set such that at least one of an amplitude and a carrier to noise ratio (CNR) of a signal obtained by reproducing information from the groove is approximately identical to that from the land.
Inventors
- 👤 Eiji Ohno
- 👤 Kenichi Nishiuchi
- 👤 Yoshitaka Sakaue
- 👤 Kazuhisa Ide
- 👤 Naoyasu Miyagawa
- 👤 Nobuo Akahira
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:19
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/007; G11B7/00718; G11B7/24; G11B7/2407; G11B7/24085
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
227 words
An optical information recording medium comprising: a substrate including a groove having a concave shape and a land having a convex shape adjacent to the groove; and a recording layer on the substrate, wherein the recording layer consists of a material which changes between a first state and a second state whose optical property is different from that of the first state, a first portion of the optical information recording medium consisting of said material in the first state having a first reflectance, said first portion being located on both the land and the groove, and a second portion of the optical information recording medium consisting of said material in the second state having a second reflectance which is different from the first reflectance, said second portion being located on both the land and the groove, said first and second portions including user recording marks, whereby information is recorded onto the groove and the land, and wherein a ratio of the first reflectance to the second reflectance, a phase of reflected light from said material in the first state and a phase of reflected light from said material in the second state are set such that at least one of an amplitude and a carrier to noise ratio (CNR) of a signal obtained by reproducing information from the groove is approximately identical to that from the land.
Claim 2
Dependent Claim
227 words
An optical information recording medium comprising: a substrate including a groove having a concave shape and a land having a convex shape adjacent to the groove; and a recording layer on the substrate, wherein the recording layer consists of a material which changes between a first state and a second state whose optical property is different from that of the first state, a first portion of the optical information recording medium consisting of said material in the first state having a first reflectance, said first portion being located on both the land and the groove, and a second portion of the optical information recording medium consisting of said material in the second state having a second reflectance which is different from the first reflectance, said second portion being located on both the land and the groove, said first and second portions including user recording marks, whereby information is recorded onto the groove and the land, and wherein a ratio of the first reflectance to the second reflectance, a phase of reflected light from said material in the first state and a phase of reflected light from said material in the second state are set such that at least one of an amplitude and a carrier to noise ratio (CNR) of a signal obtained by reproducing information from the groove is approximately identical to that from the land.
Claim 3
Dependent Claim
112 words
An optical information recording medium according to claim 1, wherein a difference D in height between the groove and the land satisfies a relation expressed by: λ/(8n)<D<λ/(4n), where a width of the groove is wider than that of the land, a wavelength of reproducing light is λ and a refractive index of the substrate is n, a relation expressed by: 0≦R2/R1≦0.2 is satisfied, where the first reflectance is R1 and the second reflectance is R2, and a relation expressed by: 2mπ<φ1 -φ2<(1+2m)π (m is an integer), where the phase of the reflected light from the first portion is φ1, and the phase of the reflected light from the second portion is φ2.
Claim 4
Dependent Claim
112 words
An optical information recording medium according to claim 1, wherein a difference D in height between the groove and the land satisfies a relation expressed by: λ/(8n)<D<λ/(4n), where a width of the groove is approximately identical to that of the land, a wavelength of reproducing light is λ and a refractive index of the substrate is n, a relation expressed by: 0≦R2/R1≦0.2 is satisfied, where the first reflectance is R1 and the second reflectance is R2, and a relation expressed by: 2mπ<φ1-φ2<(1+2m)π (m is an integer), where the phase of the reflected light from the first portion is φ1, and the phase of the reflected light from the second portion is φ2.
Claim 5
Dependent Claim
165 words
An optical information recording medium according to claim 1, wherein the substrate is duplicated from a stamper previously having a convex portion and a concave portion on a surface, the substrate being fabricated so that a land face of the substrate corresponds to a transcription face of a resist face of a glass master disk for fabricating the stamper and a groove face corresponds to a transcription face of a glass face of the glass master disk, a difference D in height between the groove and the land satisfies a relation expressed by: λ/(8n)<D<λ/(4n), where a wavelength of reproducing light is λ and a reflectance of the substrate is n, a relation expressed by: 0≦R2/R1≦0.2 is satisfied, where the first reflectance is R1 and the second reflectance is R2, and a relation expressed by: 2mπ<φ1-φ2<(1+2m)π (m is an integer), where the phase of the reflected light from the first portion is φ1, and the phase of the reflected light from the second portion is φ2.
Claim 6
Dependent Claim
122 words
An optical information recording medium according to claim 1, wherein the substrate is reproduced by an injection method from a stamper previously having a convex portion and a concave portion on a surface, a difference D in height between the groove and the land satisfies a relation expressed by: λ/(8n)<D<λ/(4n), where a wavelength of reproducing light is λ and a refractive index of the substrate is n, a relation expressed by: 0≦R2/R1≦0.2 is satisfied, where the first reflectance is R1 and the second reflectance is R2, and a relation expressed by: 2mπ<φ1-φ2<(1+2m)π (m is an integer), where the phase of the reflected light from the first portion is φ1, and the phase of the reflected light from the second portion is φ2.
Claim 7
Dependent Claim
111 words
An optical information recording medium according to claim 1, wherein a difference D in height between the groove and the land satisfies a relation expressed by: λ/(8n)<D<λ/(4n), where a width of the land is wider than that of the groove, a wavelength of reproducing light is λ and a refractive index of the substrate is n, a relation expressed by: 0≦R2/R1≦0.2 is satisfied, where the first reflectance is R1 and the second reflectance is R2, and a relation expressed by: (2m-1)π<φ1-φ2<2mπ (m is an integer), where the phase of the reflected light from the first portion is φ1, and the phase of the reflected light from the second portion is φ2.
Claim 8
Dependent Claim
65 words
An optical information recording medium according to claim 1, wherein a difference D in height between the groove and the land satisfies a relation expressed by: λ/(8n)<D<λ/(4n), where a width of the groove is approximately identical to that of the land, a wavelength of reproducing light is λ and a refractive index of the substrate is n, and the second reflectance R2 is approximately 0%.
Claim 9
Dependent Claim
93 words
An optical information recording medium according to claim 1, wherein a difference D in height between the groove and the land satisfies a relation expressed by: λ/(8n)<D<λ/(4n), where a width of the groove is approximately identical to that of the land, a wavelength of reproducing light is λ and a refractive index of the substrate is n, and a relation expressed by: φ1-φ2=(1+2m)π (m is an integer), where the phase of the reflected light from the first portion is φ1, and the phase of the reflected light from the second portion is φ2.
Claim 10
Dependent Claim
93 words
An optical information recording medium according to claim 1, wherein a difference D in height between the groove and the land satisfies a relation expressed by: λ/(8n)<D<λ/(4n), where a width of the groove is approximately identical to that of the land, a wavelength of reproducing light is λ and a refractive index of the substrate is n, and a relation expressed by: φ1-φ2=2mπ (m is an integer), where the phase of the reflected light from the first portion is φ1, and the phase of the reflected light from the second portion is φ2.
Claim 11
Dependent Claim
165 words
An optical information recording medium according to claim 1, wherein the substrate is duplicated from a stamper previously having a convex portion and a concave portion on a surface, the substrate being fabricated such that a groove face of the substrate corresponds to a transcription face of a resist face of a glass master disk for fabricating the stamper and a land face corresponds to a transcription face of a glass face of the glass master disk, a difference D in height between the groove and the land satisfies a relation expressed by: λ/(8n)<D<λ/(4n), where a wavelength of reproducing light is λ and a reflectance of the substrate is n, a relation expressed by: 0≦R2/R1≦0.2 is satisfied, where the first reflectance is R1 and the second reflectance is R2, and a relation expressed by: (2m-1)π<φ1-φ2<2mπ (m is an integer), where the phase of the reflected light from the first portion is φ1, and the phase of the reflected light from the second portion is φ2.
Claim 12
Dependent Claim
30 words
An optical information recording medium according to any one of claims 2 to 10, wherein the difference D in height between the groove and the land satisfies a relation: λ/(8n)<D≦λ/(5n).
Claim 13
Dependent Claim
25 words
An optical information recording medium according to claim 11, wherein the difference D in height between the groove and the land satisfies a relation: λ/(7n)≦D≦λ/(5n).
Claim 14
Dependent Claim
32 words
An optical information recording medium according to claim 1, wherein the material which consists of the recording layer reversibly changes between the first state and the second state due to light irradiation.
Claim 15
Dependent Claim
21 words
An optical information recording medium according to claim 13, wherein the first state and the second state belong to different phases.
Claim 16
Dependent Claim
33 words
An optical information recording medium according to claim 1, wherein a first dielectric layer, the recording layer, a second dielectric layer and a reflective layer are formed on the substrate in this order.
Claim 17
Dependent Claim
21 words
An optical information recording medium according to any one of claims 2 to 10, wherein m in the relation is 0.
References Cited (Backward Citations)
JPS6357859A
Cited
JPH0273537A
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US5249175A
Cited
US5274623A
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JPH05128589A
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JPH05282705A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-04-27 | 2001-10-27 | 2002-04-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-04-27 | 2005-10-27 | 2006-04-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-04-27 | 2009-10-27 | 2010-04-28 | $7700.00 | Window Closed / Lapsed |