Patent ID: 7361963

Claim:
An optical film formed on a major surface of a substrate, the optical film comprising: a metal film formed on the major surface of the substrate; and at least one set of a plurality of first island structures formed scattered as islands on a major surface of said metal film and a plurality of second island structures formed scattered as islands on the major surface of the substrate; wherein said at least one set of the plurality of first island structures and the plurality of second island structures are made of at least one selected from the group consisting of metals and metal oxides having a different standard electrode potential to a metal of said metal film, and wherein said metal film is made of at least one selected from the group consisting of metals having a positive standard electrode potential, and said at least one set of the plurality of first island structures and the plurality of secon disland structures are made of at least one selected from the group consisting of metals and metal oxides having a negative standard electrode potential.