Mesogen polarizer
The present invention relates to a polarization filter for ophthalmic lenses. The polarization filter comprises a mesogen layer coated onto a retardation film, either directly or through an adhesive layer. The present invention further discloses that the polarization filter formed by employing a thin film or sheet, having a defined level of retardation between the light source and the mesogen layer, for example, a cholesteric mesogen layer, the multilayered laminate structure demonstrates linear polarization of the light transmitted through the mesogen laminate structure, and, hence, can be used in ophthalmic lenses, e.g. spectacle or eyeglass lenses. The polarization filter enhances the performance by allowing transmission of the polarization filter closer to the theoretical maximum transmission.
1. A multi-layer laminate for ophthalmic lenses comprising:
a thin film layer having a defined level of retardation;
at least one mesogen coating layer disposed on one side of said retardation thin-film layer; and
wherein said laminate exhibits, in a visible region, both a polarization efficiency of greater than 50% and a percentage of luminous transmission of greater than 50% layer.
2. The laminate of claim 1 , wherein said at least one mesogen layer is attached to said retardation thin film through an adhesive layer.
3. The laminate of claim 2 , wherein said adhesive layer includes a urethane adhesive, an acrylate adhesive or an epoxy adhesive.
4. The laminate of claim 3 , wherein a thickness of said adhesive layer is in a range of 0.1 to 5 microns.
5. The laminate of claim 1 , wherein said at least one mesogen layer is interposed between two retardation thin films.
6. The laminate of claim 1 , wherein a support layer is attached to a side of said at least one mesogen layer opposite to a side said retardation thin film is attached.
7. The laminate of claim 6 , wherein said support layer comprises a polycarbonate film or a polyvinyl alcohol film.
8. The laminate of claim 7 , wherein said support layer is attached to said side of said at least one mesogen layer through an adhesion layer.
9. The laminate of claim 1 , wherein said thin film having said defined level of retardation is in a range of 50-260 nm with a target of 147 nm.
10. The laminate of claim 1 , wherein a plurality of mesogen layers are coated onto said retardation thin film.