Worm optical recording medium

• US 8,147,942 B2
• Filed: 04/01/2008
• Issued: 04/03/2012
• Est. Priority Date: 04/02/2007
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Sasa, Noboru, Fujiwara, Masayuki, Hayashi, Yoshitaka, Fujii, Toshishige, Sasaki, Toshihide, Sekiguchi, Hiroyoshi, Yasufuku, Hideyuki, Tanaka, Kawori, Makita, Kengo, Iwata, Noriyuki
• Primary Examiner(s): MULVANEY, ELIZABETH EVANS
• Application Number:
  US12/303,231
• Publication Number:
  US 20090197117A1
• Time in Patent Office: 1,463 Days
• Field of Search: 428/64.4, 430/270.12
• US Class Current: 428/64.1
• CPC Class Codes: G11B 2007/2431 group 13 elements (B, Al, Ga, In)
• CPC Class Codes: G11B 2007/24314 group 15 elements (e.g. Sb, Bi)
• CPC Class Codes: G11B 2007/24316 group 16 elements (i.e. chalcogenides, Se, Te)
• CPC Class Codes: G11B 2007/2432 Oxygen
• CPC Class Codes: G11B 2007/25706 containing transition metal elements (Zn, Fe, Co, Ni, Pt)
• CPC Class Codes: G11B 2007/2571 containing group 14 elements except carbon (Si, Ge, Sn, Pb)
• CPC Class Codes: G11B 2007/25711 containing carbon
• CPC Class Codes: G11B 2007/25713 containing nitrogen
• CPC Class Codes: G11B 2007/25715 containing oxygen
• CPC Class Codes: G11B 2007/25716 containing sulfur
• CPC Class Codes: G11B 7/24035 Recording layers substrates also used as recording layers G11B7/24047
• CPC Class Codes: G11B 7/246 containing dyes
• CPC Class Codes: G11B 7/2578 consisting essentially of inorganic materials
• CPC Class Codes: Y10T 428/21 Circular sheet or circular blank

Abstract

A write-once-read-many optical recording medium is disclosed that includes a support substrate; a recording layer on the support substrate, the recording layer containing an oxide of one of a metal and a metalloid as a principal component; and a layer adjacent to the recording layer. The recording layer includes a region where a constituent element of the adjacent layer is dispersed. Recording and reproduction are performable with laser light of a blue wavelength region.

Claims

1. A write-once-read-many optical recording medium, comprising:

a support substrate; and

a recording layer and a layer adjacent to the recording layer on the support substrate, the recording layer containing an oxide of one of a metal and a metalloid as a principal component,

wherein the recording layer includes a region where a constituent element of the adjacent layer is dispersed, and

recording and reproduction are performable with laser light of a blue wavelength region, and

wherein the write-once-read-many optical recording medium further comprises;

an additional layer adjacent to the recording layer, wherein positions at which a number of atoms of the one of the metal and the metalloid of the oxide is a half of a maximum of the number of atoms in the recording layer in an analysis of a composition of the write-once-read-many optical recording medium in a direction of a film thickness thereof are defined as interfaces between the recording layer and the adjacent layer and the additional adjacent layer, and a ratio of the element of the adjacent layer at a center of the recording layer is more than or equal to 5 at % of elements of the recording layer, the center of the recording layer being determined by the interfaces.

2. The write-once-read-many optical recording medium as claimed in claim 1, wherein the recording and the reproduction are performed from a side of the support substrate, and the adjacent layer is provided on a side of the recording layer opposite to the side of the support substrate.

3. The write-once-read-many optical recording medium as claimed in claim 1, wherein the recording and the reproduction are performed from a side opposite to the support substrate, and the adjacent layer is provided on a side of the recording layer opposite to the support substrate.

4. The write-once-read-many optical recording medium as claimed in claim 1, wherein the adjacent layer contains one of an oxide, a nitride, a carbide, a fluoride, and a sulfide, and the constituent element of the adjacent layer dispersed in the region in the recording layer is bonded to one of oxygen, nitrogen, carbon, fluorine, and sulfur in the one of the oxide, the nitride, the carbide, the fluoride, and the sulfide.

5. The write-once-read-many optical recording medium as claimed in claim 4, wherein the adjacent layer contains ZnS as a principal component, and the constituent element of the adjacent layer dispersed in the region in the recording layer is Zn.

6. The write-once-read-many optical recording medium as claimed in claim 1, further comprising:

a protective layer, wherein the recording layer, the adjacent layer, and the protective layer are successively stacked in order, and the adjacent layer contains a simple substance of at least one element M as a principal component, the at least one element M reinforcing a light absorbing function with respect to the laser light.

7. The write-once-read-many optical recording medium as claimed in claim 1, wherein the one of the metal and the metalloid is bismuth.

8. The write-once-read-many optical recording medium as claimed in claim 1, wherein a value of an imaginary part of a complex index of refraction of the recording layer is more than or equal to 0.30 and a value of a real part of the complex index of refraction of the recording layer is more than or equal to 2.20 when the recording layer is exposed to the laser light.

9. A write-once-read-many optical recording medium, comprising:

a support substrate; and

a recording layer and a layer adjacent to the recording layer on the support substrate, the recording layer containing an oxide of one of a metal and a metalloid and a simple substance of at least one element M as a principal component,

wherein the recording layer includes a region where a constituent element of the adjacent layer is dispersed,

recording and reproduction are performable with laser light of a blue wavelength region, and

the at least one element M reinforces a light absorbing function with respect to the laser light, and

wherein the write-once-read-many optical recording medium further comprises;

an additional layer adjacent to the recording layer, wherein positions at which a number of atoms of the one of the metal and the metalloid of the oxide is a half of a maximum of the number of atoms in the recording layer in an analysis of a composition of the write-once-read-many optical recording medium in a direction of a film thickness thereof are defined as interfaces between the recording layer and the adjacent layer and the additional adjacent layer, and a ratio of the element of the adjacent layer at a center of the recording layer is more than or equal to 5 at % of elements of the recording layer, the center of the recording layer being determined by the interfaces.

10. The write-once-read-many optical recording medium as claimed in claim 9, wherein the recording and the reproduction are performed from a side of the support substrate, and the adjacent layer is provided on a side of the recording layer opposite to the side of the support substrate.

11. The write-once-read-many optical recording medium as claimed in claim 9, wherein the recording and the reproduction are performed from a side opposite to the support substrate, and the adjacent layer is provided on a side of the recording layer opposite to the support substrate.

12. The write-once-read-many optical recording medium as claimed in claim 9, wherein the adjacent layer contains one of an oxide, a nitride, a carbide, a fluoride, and a sulfide, and the constituent element of the adjacent layer dispersed in the region in the recording layer is bonded to one of oxygen, nitrogen, carbon, fluorine, and sulfur in the one of the oxide, the nitride, the carbide, the fluoride, and the sulfide.

13. The write-once-read-many optical recording medium as claimed in claim 12, wherein the adjacent layer contains ZnS as a principal component, and the constituent element of the adjacent layer dispersed in the region in the recording layer is Zn.

14. The write-once-read-many optical recording medium as claimed in claim 9, further comprising:

a protective layer, wherein the recording layer, the adjacent layer, and the protective layer are successively stacked in order.

15. The write-once-read-many optical recording medium as claimed in claim 9, wherein the one of the metal and the metalloid is bismuth.

16. The write-once-read-many optical recording medium as claimed in claim 9, wherein a value of an imaginary part of a complex index of refraction of the recording layer is more than or equal to 0.30 and a value of a real part of the complex index of refraction of the recording layer is more than or equal to 2.20 when the recording layer is exposed to the laser light.

17. A write-once-read-many optical recording medium, comprising:

a support substrate; and

a recording layer on the support substrate,

wherein recording and reproduction are performable with laser light of a blue wavelength region,

the recording layer includes an M element dispersion region formed of at least one element M reinforcing a light absorbing function with respect to the laser light, the at least one element M being buried in the recording layer after formation of the recording layer, and

the recording layer is one of

(a) a recording layer containing an oxide of one of a metal and a metalloid as a principal component;

(b) a recording layer containing an oxide of one of a metal and a metalloid and a simple substance of an element of the oxide which element is bonded to oxygen as a principal component;

(c) a recording layer containing an oxide of one of a metal and a metalloid and the simple substance of the at least one element M as a principal component;

(d) a recording layer containing an oxide of one of a metal and a metalloid, the simple substance of the at least one element M, and an oxide of the at least one element M as a principal component; and

(e) a recording layer containing an oxide of one of a metal and a metalloid, a simple substance of an element of the oxide which element is bonded to oxygen, the simple substance of the at least one element M, and an oxide of the at least one element M as a principal component, and

wherein a value of an imaginary part of a complex index of refraction of the recording layer is more than or equal to 0.30 and a value of a real part of the complex index of refraction of the recording layer is more than or equal to 2.20 when the recording layer is exposed to the laser light.