Metal alloys for the reflective or the semi-reflective layer of an optical storage medium

• US 20070104918A1
• Filed: 05/10/2005
• Published: 05/10/2007
• Est. Priority Date: 07/21/2000
• Status: Active Grant

• Current Assignee: Target Technology Company LLC
• Original Assignee: Target Technology Company LLC
• Inventors: Nee, Han
• Granted Patent: US 7,314,657 B2
• Time in Patent Office: Days
• US Class Current: 428/64.400
• CPC Class Codes: C22C 5/06 Alloys based on silver
• CPC Class Codes: C22C 5/08 with copper as the next major constituent
• CPC Class Codes: C22F 1/14 of noble metals or alloys based thereon
• CPC Class Codes: C23C 14/185 by cathodic sputtering
• CPC Class Codes: G11B 11/10584 characterised by the form, e.g. comprising mechanical protection elements
• CPC Class Codes: G11B 11/10586 characterised by the selection of the material
• CPC Class Codes: G11B 2007/24312 group 14 elements (e.g. Si, Ge, Sn)
• 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 7/00454 involving phase-change effects
• CPC Class Codes: G11B 7/00455 involving reflectivity, absorption or colour changes
• CPC Class Codes: G11B 7/24038 Multiple laminated recording layers
• CPC Class Codes: G11B 7/243 comprising inorganic materials only, e.g. ablative layers
• CPC Class Codes: G11B 7/246 containing dyes
• CPC Class Codes: G11B 7/2534 polycarbonates [PC]
• CPC Class Codes: G11B 7/257 of layers having properties involved in recording or reproduction, e.g. optical interference layers or sensitising layers or dielectric layers, which are protecting the recording layers
• CPC Class Codes: G11B 7/258 of reflective layers
• CPC Class Codes: G11B 7/259 based on silver
• CPC Class Codes: G11B 7/2595 based on gold
• CPC Class Codes: Y10T 428/21 Circular sheet or circular blank

Abstract

A silver-based alloy thin film is provided for the highly reflective or the semi-reflective layer of optical discs. Alloy additions to silver include gold, rhodium, ruthenium, osmium, platinum, palladium, copper, silicon, cadmium, tin, lithium, nickel, cobalt, manganese, indium, chromium, antimony, gallium, boron, molybdenum, zirconium, beryllium, titanium, aluminum, germanium and zinc. These alloys have moderate to high reflectivity and reasonable corrosion resistance in ambient environments.

Claims

1. An optical storage medium, comprising:

a first layer having a pattern of features in at least one major surface;

a semi-reflective layer adjacent the pattern of features in said first layer, the semi-reflective layer including a metal alloy, said metal alloy including silver, copper and manganese, wherein the relationship between the amounts of silver, copper and manganese in said metal alloy is defined by Ag_xCu_yMn_z, wherein 0.9<

x<

0.9998, 0.0001<

y<

0.05 and 0.0001<

z<

0.05;

a second layer having a pattern of features in at least one major surface; and

a reflective layer adjacent the pattern of features in said second layer.

2. The optical storage medium according to claim 1, wherein said metal alloy includes titanium and wherein the relationship between the amounts of silver and titanium in the metal alloy is Ag_xTi_t wherein 0.95<

x<

0.9999, 0.0001<

t<

0.05.

3. The optical storage medium according to claim 2, wherein 0.91<

x<

0.997, 0.001<

y<

0.03, 0.001<

z<

0.03, and 0.001<

t<

0.03.

4. An optical storage medium, comprising:

a first layer having a pattern of features in at least one major surface;

a semi-reflective layer adjacent the pattern of features in said first layer, the semi-reflective layer including a metal alloy, said metal alloy including silver, copper and titanium, wherein the relationship between the amounts of silver, copper and titanium in said metal alloy is defined by Ag_xCu_yTi_t, wherein 0.9<

x<

0.9998, 0.0001<

y<

0.05 and 0.0001<

t<

0.05;

a second layer having a pattern of features in at least one major surface; and

a reflective layer adjacent the pattern of features in said second layer.

5. The optical storage medium according to claim 4, wherein said metal alloy includes manganese and wherein the relationship between the amounts of silver and manganese in the metal alloy is Ag_xMn_z wherein 0.95<

z<

0.9999, 0.0001<

t<

0.05.

6. The optical storage medium according to claim 5, wherein 0.91<

x<

0.997, 0.001<

y<

0.03, 0.001<

z<

0.03, and 0.001<

t<

0.03.

7. An optical storage medium, comprising:

a first layer having a pattern of features in at least one major surface;

a semi-reflective layer adjacent the pattern of features in said first layer, the semi-reflective layer including a metal alloy, said metal alloy including silver, copper and tin, wherein the relationship between the amounts of silver, copper, and tin in said metal alloy is defined by Ag_xCu_ySn_s, wherein 0.9<

x<

0.9998, 0.0001<

y<

0.05 and 0.0001<

s<

0.05;

a second layer having a pattern of features in at least one major surface; and

a reflective layer adjacent the pattern of features in said second layer.

8. The optical storage medium according to claim 7, wherein 0.94<

x<

0.997, 0.001<

y<

0.03, 0.001<

s<

0.03.