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US 4,806,289 AGranted
Method of making a hollow light pipe
AssigneeThe Dow Chemical Company
InventorsLarry J. Laursen, Virgil W. Coomer, Walter J. Schrenk
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Abstract
A hollow light conductor with enhanced light-transmitting properties is formed by the coextrusion of polymeric materials. The hollow light conductor comprises a continuous annular core layer encased in inner and outer cladding layers.
Claims8
A method of constructing a hollow light conductor, comprising the steps of:
- heat plasticizing a core material which is capable of conducting light;
- heat plasticizing a cladding material which has an index of refraction that is lower than the index of refraction of said core material;
- coextruding said cladding material along the inner and outer surfaces of said core material to form a tri-layer hollow light conductor having smooth surfaces between said core material and said cladding material with said core material being formed in a predetermined shape;
- and
- cooling said light conductor below the glass transition temperatures of said cladding and core materials so that said light conductor will maintain said predetermined shape.
2 more elements
Dependencies are inferred from the claim text.