Top stabilized photochromic lens system
AssigneeExxene Corporation
InventorsEdward A. Bernheim, Benjamin W. Raglin
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Abstract
A method and apparatus for the stabilizing of napthopyran and spiroxazine photochromic dye in a coating or plastic media is presented. As prolonged exposure to light causes degradation of the photochromic properties of the dyes, a two-tiered layering system is utilized in which a hindered amine stabilizer (HALS) and/or an ultraviolet light (UV) absorber, is placed as a clear coat layer above a bottom layer containing the photochromic dyes. The bottom layer is constructed containing the photochromic dyes by either a coating of a surface of a lens or an imbuing of the photochromic dyes into the lens material, and can further optionally contain a HALS and/or UV blocking compound itself.
Claims9
An optical part including an optical substrate providing a photochromic dye, a light transmitting protective layer on the substrate, the protective layer consisting essentially of 75-99.9% by weight of a binder, 0.1-20% by weight of a protectant selected from the group consisting essentially of a hindered amine light stabilizer, an ultraviolet light absorber, and mixtures thereof and 0-5% by weight anti-oxidant so that selected wave lengths of light passing through the protective layer are filtered before they reach and destabilize the photochromic dye.
Dependencies are inferred from the claim text.