US Patent 7618908 Visible light optical polarizer made from stretched H

The invention is directed to a method for preparing visible light optical polarizers using a non-halide silver salt and any glass composition that the non-halide silver salts is soluble, provided that the glass composition, including the silver salt, was a halide content that is, on a molar basis, 10% or less than the silver content, on a molar basis, of the glass composition. The silver containing glass is hydrogen reduced prior to stretching to form an optical polarizer. The invention enables one to form a visible light polarizer having a polarizing layer thickness in the range 10-40 μm in which the silver particles have a surround index sufficiently removed from the blue polarizer region to allow good contrast.