Optical element and method for producing optical element

Abstract

An optical element having a substrate and a light-shielding film on part of an outer portion of the substrate further contains a coating on the light-shielding film, the coating containing a cured mixture of a melamine or benzoguanamine resin, and a phenolic resin, in proportions by mass of 1:5 to 7:5.

What is claimed is: 
     
         1 . A method for producing an optical element, the method comprising:
 forming a light-shielding film on an outer portion of a substrate; and   forming a coating on a surface of the light-shielding film, the coating containing a cured mixture of a methylol melamine or methylol benzoguanamine resin, and a phenolic resin, in proportions of 1:5 to 7:5.   
     
     
         2 . The method according to  claim 1 , wherein the coating contains a condensation product of the methylol melamine or methylol benzoguanamine resin and the phenolic resin. 
     
     
         3 . The method according to  claim 2 , wherein the coating contains a condensation product of the benzoguanamine resin and the phenolic resin. 
     
     
         4 . The method according to  claim 3 , wherein the substrate is a piece of glass. 
     
     
         5 . The method according to  claim 4 , wherein the optical element is a lens or a prism. 
     
     
         6 . The method according to  claim 1 , further comprising:
 forming an antireflection film on the substrate after the formation of the coating,   wherein the formation of the antireflection film involves forming a film of aluminum oxide and making the film of aluminum oxide in contact with water at a temperature of 40° C. or more and 100° C. or less to give a surface of the film of aluminum oxide a textured structure formed by crystals mainly of an aluminum hydroxide or a hydrate of an aluminum oxide.   
     
     
         7 . The method according to  claim 6 , further comprising:
 washing the substrate with an alkaline solution before the formation of the antireflection film.   
     
     
         8 . An optical equipment comprising:
 a lens including the optical element produced by the method defined in  claim 1 ; or   a prism including the optical element produced by the method defined in  claim 1 ; or   a reflector including the optical element produced by the method defined in  claim 1 ; or   a diffraction grating including the optical element produced by the method defined in  claim 1 .   
     
     
         9 . A camera comprising a lens including the optical element produced by the method defined in  claim 1 .