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US 5,793,456 AGranted
Cholesteric polarizer and the manufacture thereof
AssigneeU.S. Philips Corporation
InventorsDirk J. Broer, Johan Lub
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AssigneeU.S. Philips Corporation
InventorsDirk J. Broer, Johan Lub
Estimating the term…
Cholesteric polarizer and the manufacture thereof. A broadband cholesteric polarizer is described, as well as a method of manufacturing such a polarizer. Said polarizer comprises an optically active layer of a polymer material having a cholesteric order, said material being oriented so that the axis of the molecular helix extends transversely to the layer. In accordance with the invention, the polarizer is characterized in that the pitch of the molecular helix in the layer is varied in such a manner that the difference between the maximum pitch and the minimum pitch is at least 100 nm. The optically active layers are preferably provided on substrates which bring about a conversion of circularly polarized light into linearly polarized light. Three different methods of manufacturing such broadband polarizers are described.
A cholesteric polarizer comprising an optically active layer of a polymer material, the polymer material having a cholesteric order and a molecular helix, the molecular helix having an axis extending transversely to the layer, wherein a pitch of the molecular helix in the layer varies with a difference between a maximum pitch and a minimum pitch of at least 100 nm, said polymer material further comprising a three-dimensional network.
A lighting device comprising a socket for an electric light source, a reflector and a cholesteric polarizer which is provided with a quarter-wave plate, wherein said cholesteric polarizer comprises an optically active layer of a polymer material, the polymer material having a cholesteric order and a molecular helix, the molecular helix having an axis extending transversely to the layer, wherein a pitch of the molecular helix in the layer varies with a difference between a maximum pitch and a minimum Pitch of at least 100 nm, said polymer material further comprising a three-dimensional network.
A lighting device comprising a socket for an electric light source, a reflector, and a cholesteric polarizer which is provided with a quarter-wave plate, characterized in that said cholesteric polarizer comprises an optically active layer of a polymer material, the polymer material having a cholesteric order and a molecular helix, the molecular helix having an axis extending transversely to the layer, wherein a pitch of the molecular helix in the layer varies with a difference between a maximum pitch and a minimum pitch of at least 100 nm, further characterized in that the pitch of the molecular helix increases substantially continuously from a minimum value at one surface of the layer to a maximum value at the other surface of the layer, further wherein said polymer material further comprises a three-dimensional network.
Dependencies are inferred from the claim text.