The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 09, 1998
Filed:
Jun. 14, 1996
Rifat A Hikmet, Eindhoven, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
The invention relates to a switchable cholesteric filter. Said filter comprises an optically active layer which is situated between two substrates which are both provided with an electrode for applying an electric field. The optically active layer comprises a liquid-crystalline material which is in the cholesteric phase. In accordance with the invention, the optically active layer comprises a three-dimensional polymer network which consists of the polymerization product of maximally 2 wt. % of monomers with at least two polymerizable groups and maximally 30 wt. % of liquid-crystalline monomers with one polymerizable group, and the rest of the optically active layer consists predominantly of a mixture of chiral and achiral liquid-crystalline molecules. An optically active layer of this composition can be switched in a simple and reproducible manner by means of an electric field. The invention also relates to a luminaire comprising such a switchable cholesteric filter.