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

Abstract

A silver-based alloy thin film is provided for the highly reflective or semi-reflective coating layer of optical discs. Elements that can be added to silver to produce useful silver alloys include zinc, aluminum, copper, manganese, germanium, yttrium, bismuth, scandium, and cobalt. These alloys have moderate to high reflectivity and reasonable corrosion resistance in the ambient environment.

1 . An optical storage medium, comprising:
 a first layer formed of a transparent resin and having a first stamped or molded pattern of pits and lands in at least one major surface; and   a first coating adjacent and conforming to said pit-and-land pattern,   said first coating being semi-reflective, and   said first coating including a metal alloy,   said metal alloy including silver and yttrium,   wherein the relationship between the amounts of silver and yttrium in the metal alloy is defined by Ag x Y w  where 0.9500<x<0.9999 and 0.0001<w<0.05.   
   
   
       2 . The optical storage medium of  claim 1 , wherein 0.001<w<0.03. 
   
   
       3 . The optical storage medium of  claim 1 , further comprising:
 a second layer formed of a transparent resin and having a second stamped or molded pattern of pits and lands in at least one major surface; and   a second coating adjacent and conforming to said pit-and-land pattern,   said second coating being highly reflective.   
   
   
       4 . The optical storage medium of  claim 3 , wherein said second coating includes said metal alloy. 
   
   
       5 . An optical storage medium, comprising:
 a first layer formed of a transparent resin and having a first stamped or molded pattern of pits and lands in at least one major surface; and   a first coating adjacent and conforming to said pit-and-land pattern,   said first coating being semi-reflective, and   said first coating including a metal alloy,   said metal alloy including silver and scandium,   wherein the relationship between the amounts of silver and scandium in the metal alloy is defined by Ag x Sc w  where 0.9500<x<0.9999 and 0.0001<w<0.05.   
   
   
       6 . The optical storage medium of  claim 5 , wherein 0.001<w<0.03. 
   
   
       7 . The optical storage medium of  claim 5 , further comprising:
 a second layer formed of a transparent resin and having a second stamped or molded pattern of pits and lands in at least one major surface; and   a second coating adjacent and conforming to said pit-and-land pattern,   said second coating being highly reflective.   
   
   
       8 . The optical storage medium of  claim 7 , wherein said second coating includes said metal alloy. 
   
   
       9 . An optical storage medium, comprising:
 a first layer formed of a transparent resin and having a first stamped or molded pattern of pits and lands in at least one major surface; and   a first coating adjacent and conforming to said pit-and-land pattern,   said first coating being semi-reflective, and   said first coating including a metal alloy,   said metal alloy including silver and bismuth,   wherein the relationship between the amounts of silver and bismuth in the metal alloy is defined by Ag x Bi w  where 0.9500<x<0.9999 and 0.0001<w<0.05.   
   
   
       10 . The optical storage medium of  claim 9 , wherein 0.001<w<0.03. 
   
   
       11 . The optical storage medium of  claim 9 , further comprising:
 a second layer formed of a transparent resin and having a second stamped or molded pattern of pits and lands in at least one major surface; and   a second coating adjacent and conforming to said pit-and-land pattern,   said second coating being highly reflective.   
   
   
       12 . The optical storage medium of  claim 9 , wherein said second coating includes said metal alloy. 
   
   
       13 . An optical storage medium, comprising:
 a first layer formed of a transparent resin and having a first stamped or molded pattern of pits and lands in at least one major surface; and   a first coating adjacent and conforming to said pit-and-land pattern,   said first coating being semi-reflective, and   said first coating including a metal alloy,   said metal alloy including silver, copper, and element A, where A is selected from the group of elements consisting of yttrium, scandium, and bismuth,   wherein the relationship between the amounts of silver, copper, and element A in the metal alloy is defined by Ag x Cu z A w  where 0.85<x<0.9998, 0.0001<z<0.10, and 0.0001<w<0.05.   
   
   
       14 . The optical storage medium of  claim 1 , wherein 0.001<w<0.03. 
   
   
       15 . The optical storage medium of  claim 1 , further comprising:
 a second layer formed of a transparent resin and having a second stamped or molded pattern of pits and lands in at least one major surface; and   a second coating adjacent and conforming to said pit-and-land pattern,   said second coating being highly reflective.   
   
   
       16 . The optical storage medium of  claim 3 , wherein said second coating includes said metal alloy.