US PATENT SUBCLASS 349 / 120
.~.~.~.~ Including at least one with negative intrinsic birefringence

Current as of: June, 1999
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349 /   HD   LIQUID CRYSTAL CELLS, ELEMENTS AND SYSTEMS

56  DF  PARTICULAR STRUCTURE {7}
84  DF  .~ Having significant detail of cell structure only {17}
117  DF  .~.~ Compensator or retarder (i.e., not using liquid crystal cell) {3}
119  DF  .~.~.~ Multiple compensators {1}
120.~.~.~.~ Including at least one with negative intrinsic birefringence

DEFINITION

Classification: 349/120

Including at least one with negative intrinsic birefringence:

(under subclass 119) Subject matter wherein at least one of the plural compensators or retarders has a negative refractive index anisotropy.

(1) Note. Materials that have a negative intrinsic birefringence include polystyrene and styrene copolymers, whereas materials that have a positive intrinsic birefringence include polycarbonate.