US5124232A
Expired / Lapsed
US
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Optical recording medium
Assignee: Toray Industries Inc
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Filing: 1990-08-02
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Granted: 1992-06-23
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Expires: 2010-08-02
Abstract
Abstract An optical recording medium includes at least a substrate and a recording layer formed on the substrate, said recording layer being irradiated with an energy beam to change the optical properties thereof by directly or indirectly generated heat, thereby recording information, wherein said recording layer comprises four elements of tellurium (Te), germanium (Ge), gallium (Ga) and bismuth (Bi) and has a composition represented by the following formula: (Te.sub.x Ge.sub.1-x).sub.1-y (Ga.sub.z Bi.sub.1-z).sub.y wherein 0.40≦x≦0.75 0.02≦y≦0.30 and 0.05≦z≦0.50, x is the molar fraction of Te in Te-Ge, y is the molar fraction of the total amount of Bi and Ga in the recording layer, and z is the molar fraction of Ga in Ga-Bi. The optical recording medium of the present invention exhibits excellent CNR and recording sensitivity, no significant noise, a large amplitude of read-out signal, no significant jitter fluctuation excellent capability for high-speed and high-density recording, excellent life of media and resistance to moisture-and-heat, and high reliability.
Inventors
- 👤 Toshiharu Nakanishi
- 👤 Naoya Seo
- 👤 Gentaro Ohbayashi
- 👤 Osamu Watanabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 04:34
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/241; G11B7/252; G11B7/257; G11B7/242; G11B7/243; G11B2007/24302; G11B2007/2431; G11B2007/24312; G11B2007/24314; G11B2007/24316; G11B2007/25705; G11B2007/2571; G11B2007/25713; G11B7/253; G11B7/2533; G11B7/2534; G11B7/2578; Y; Y10; Y10S; Y10S430/00; Y10S430/146
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
112 words
An optical recording medium comprising at least a substrate and a recording layer formed on the substrate, said recording layer being irradiated with an energy beam to change the optical properties thereof by directly or indirectly generated heat, thereby recording information, wherein said recording layer comprises four elements of tellurium (Te), germanium (Ge), gallium (Ga) and bismuth (Bi) and has a composition represented by the following formula: (Te.sub.x Ge.sub.1-x).sub.1-y (Ga.sub.z Bi.sub.1-z).sub.y wherein 0.40≦x≦0.75, 0.02≦y≦0.30 and 0.05≦z≦0.50, x is the molar fraction of Te in Te-Ge, y is the molar fraction of the total amount of Bi and Ga in the recording layer, and z is the molar fraction of Ga in Ga-Bi.
Claim 2
Dependent Claim
112 words
An optical recording medium comprising at least a substrate and a recording layer formed on the substrate, said recording layer being irradiated with an energy beam to change the optical properties thereof by directly or indirectly generated heat, thereby recording information, wherein said recording layer comprises four elements of tellurium (Te), germanium (Ge), gallium (Ga) and bismuth (Bi) and has a composition represented by the following formula: (Te.sub.x Ge.sub.1-x).sub.1-y (Ga.sub.z Bi.sub.1-z).sub.y wherein 0.40≦x≦0.75, 0.02≦y≦0.30 and 0.05≦z≦0.50, x is the molar fraction of Te in Te-Ge, y is the molar fraction of the total amount of Bi and Ga in the recording layer, and z is the molar fraction of Ga in Ga-Bi.
Claim 3
Dependent Claim
27 words
An optical recording medium according to claim 1, wherein the composition of said recording layer is represented by the following formula: (Te.sub.x Ge.sub.1-x).sub.1-y (Ga.sub.z Bi.sub.1-z).sub.y wherein 0.45≦x≦0.70,
Claim 4
Dependent Claim
39 words
05≦y≦0.25 and 0.07≦z≦0.40, x is the molar fraction of Te in Te-Ge, y is the molar fraction of the total amount of Bi and Ga in the recording layer, and z is the molar fraction of Ga in Ga-Bi.
Claim 5
Dependent Claim
39 words
05≦y≦0.25 and 0.07≦z≦0.40, x is the molar fraction of Te in Te-Ge, y is the molar fraction of the total amount of Bi and Ga in the recording layer, and z is the molar fraction of Ga in Ga-Bi.
Claim 6
Dependent Claim
30 words
An optical recording medium according to claim 1 or 2, which further comprises a reflective layer provided on the side of the said recording layer remote from the said substrate.
Claim 7
Dependent Claim
21 words
An optical recording medium according to claim 3, wherein the said reflective layer is mainly composed of Te, Bi and Ga.
Claim 8
Dependent Claim
21 words
An optical recording medium according to claim 3, wherein the said reflective layer has a thickness of 10 to 80 nm.
Claim 9
Dependent Claim
30 words
An optical recording medium according to claim 1 or 2, which further comprises a light absorption layer provided on the side of said recording layer remote from the said substrate.
Claim 10
Dependent Claim
22 words
An optical recording medium according to claim 6, wherein the said light absorption layer has a thickness of 10 to 160 nm.
Claim 11
Dependent Claim
63 words
An optical recording medium according to claim 6, wherein the said light absorption layer has a coefficient of thermal diffusion, α, and a heat capacity, H, each at 25° C. respectively falling within the following ranges: 0.003≦α≦0.02 100≦H≦500 wherein α=k/(c.p) wherein k is the thermal conductivity (kcal/m.hr.K), c is the specific heat (kcal/kg.K) and p is the density (kg/m 3 ); and H=c.p.
Claim 12
Dependent Claim
31 words
An optical recording medium according to claim 6, wherein the said light absorption layer comprises a member selected from the group consisting of Ta nitride, Bi 2 Te 3 and TePb.
Claim 13
Dependent Claim
38 words
An optical recording medium according to claim 1 or 2, which further comprises a protective layer between the said substrate and the said recording layer and/or on the side of said recording layer remote from the said substrate.
Claim 14
Dependent Claim
54 words
An optical recording medium according to claim 10, wherein the said protective layer comprises an inorganic film selected from the group consisting of films of ZnS and MgF 2 , or oxides, carbides and nitrides of Si, Al, Ti, Zr, Te and Ge, and a mixture of said sulfides, fluorides, oxides, carbides and nitride.
Claim 15
Dependent Claim
62 words
An optical recording medium according to claim 10, wherein the said protective layer comprises an inorganic film selected from the group consisting of a compound film comprising ZrC and SiO 2 , a compound film comprising ZnS and SiO 2 , a compound film comprising TiC and SiO 2 , a compound film comprising ZnS and MgF 2 and an SiAlON film.
Claim 16
Dependent Claim
26 words
An optical recording medium according to claim 3, which further comprises a diffusion blocking layer provided between the said recording layer and the said reflective layer.
Claim 17
Dependent Claim
27 words
An optical recording medium according to claim 6, which further comprises a diffusion blocking layer provided between the said recording layer and the said light absorption layer.
Claim 18
Dependent Claim
27 words
An optical recording medium according to claim 1 or 2, which further comprises a surface coat layer provided on the surface of the said optical recording medium.
Claim 19
Dependent Claim
29 words
An optical recording medium according to claim 10, wherein the said protective layer comprises an inorganic film selected from the group consisting of films of SiO 2 and ZrC.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-06-23 | 1995-12-23 | 1996-06-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-06-23 | 1999-12-23 | 2000-06-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-06-23 | 2003-12-23 | 2004-06-23 | $7700.00 | Window Closed / Lapsed |