Method of manufacturing a switchable cholesteric filter as well as a luminaire having such a filter
First Claim
1. A method of manufacturing a switchable cholesteric filter comprising an optically active layer, in which a mixture of polymerizable, liquid-crystalline molecules is provided between two, substantially parallel substrates, which are each provided with an electrode for applying an electric field, said mixture subsequently being polymerized by means of UV light to form an optically active layer of cholesteric order comprising a three-dimensional network, characterized in that a quantity of a photo-stabilizing compound is added to the mixture, said quantity being not greater than about 5 wt. % of the overall volume of the mixture.
1 Assignment
0 Petitions
Accused Products
Abstract
The invention provides a simple method of manufacturing a broadband, switchable cholesteric filter. To this end, a mixture of polymerizable, liquid-crystalline molecules is provided between two, substantially parallel substrates, which are each provided with an electrode. This mixture is subsequently polymerized with UV light to form an optically active layer of cholesteric order comprising a three-dimensional polymeric network. If the mixture also contains a quantity of a photo-stabilizing compound, a broadband, cholesteric filter is obtained. The mixture preferably comprises, in addition to maximally 5 wt. % of the photo-stabilizing compound, maximally 2 wt. % of monomers having at least two polymerizable groups, maximally 90 wt. % of liquid-crystalline monomers having one polymerizable group, as well as a mixture of chiral and/or achiral liquid-crystalline molecules without a polymerizable group. Switchable cholesteric filters having a bandwidth of 200 nm and more can be obtained in this manner.
168 Citations
8 Claims
- 1. A method of manufacturing a switchable cholesteric filter comprising an optically active layer, in which a mixture of polymerizable, liquid-crystalline molecules is provided between two, substantially parallel substrates, which are each provided with an electrode for applying an electric field, said mixture subsequently being polymerized by means of UV light to form an optically active layer of cholesteric order comprising a three-dimensional network, characterized in that a quantity of a photo-stabilizing compound is added to the mixture, said quantity being not greater than about 5 wt. % of the overall volume of the mixture.
Specification