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

• US 6,790,503 B2
• Filed: 01/15/2003
• Issued: 09/14/2004
• Est. Priority Date: 06/22/1998
• Status: Expired due to Term

• Current Assignee: Target Technology Company LLC
• Original Assignee: Target Technology Company LLC
• Inventors: Nee, Han H.
• Primary Examiner(s): Mulvaney, Elizabeth
• Application Number:
  US10/342,649
• Publication Number:
  US 20030138591A1
• Time in Patent Office: 608 Days
• Field of Search: 428/64.1, 428/64.4, 428/457, 428/913, 430/270.11, 430/270.12, 430/495.1, 430/945
• US Class Current: 428/64.1
• 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
• CPC Class Codes: Y10T 428/31678 Of metal

Abstract

A silver-based alloy thin film is provided for the highly reflective or semi-reflective layer of optical discs. Alloy additions to silver include gold, palladium, copper, rhodium, ruthenium, osmium, iridium, and platinum. These alloys have moderate to high reflectivity and reasonable corrosion resistance in the ambient environment.

Claims

1. An optical storage medium, comprising:

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

a semi-reflective coating adjacent the first feature pattern;

said semi-reflective coating including a first metal alloy;

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

a reflective coating adjacent the second feature pattern, the reflective coating including a second metal alloy;

a spacer layer located between the first and the second layer; and

said first metal alloy including silver and copper wherein the relationship between the amount of silver and copper is defined by Ag_xCu_t where 0.900<

x<

0.999 and 0.001<

t<

0.100.

2. The medium of claim 1, wherein 0.001<

t<

0.05.

3. The medium of claim 1, said second metal alloy including silver and copper wherein the relationship between the amounts of silver and copper is defined by Ag_xCu_t where 0.900<

x<

0.999 and 0.001<

t<

0.100.

4. The medium of claim 1, wherein 0.001<

t<

0.02.

5. The medium of claim 1, wherein 0.02<

t<

0.03.

6. The medium of claim 1, wherein 0.03<

t<

0.065.

7. The medium of claim 1, wherein 0.065<

t<

0.090.

8. The medium of claim 1, wherein 0.090<

t<

0.100.