Dichroic guest-host polarizer comprising an oriented polymer film
A dichroic guest-host polarizer comprises an oriented polymerized liquid crystal host and aligned therewith a dichroic guest. The dichroic ratio of the polarizer is about 15 or more. The polarizer may have a small thickness, be manufactured using a wet deposition method, optionally in accordance with a desired pattern, and be provided on the inside of a liquid crystal cell. Polymerizable liquid crystals having a highly ordered mesophase which may be suitable used to obtain highly oriented polymer films such as polarizer films are disclosed.
1. A guest-host polarizer comprising an oriented polymer film including an oriented polymerized liquid crystal host and a dichroic light-absorbing guest dispersed and oriented in the host, the oriented polymer film having a dichroic ratio of about 15 or more; wherein the orientation of the oriented polymer film is or corresponds to the orientation of a smectic phase S x wherein the smectic phase S x is not smectic A phase or smectic C phase, and wherein the oriented polymerized liquid crystal host is obtained by polymerizing an oriented polymerizable liquid crystal.
2. A guest-host polarizer as claimed in claim 1 , wherein the oriented polymer film has a film thickness of about 10 μm or less.
3. A guest-host polarizer as claimed in claim 1 , wherein the dichroic light-absorbing guest is a blue absorbing dichroic colorant and the polarizer further comprises a thin film obtained from a perylene-based, naphthalene-based or anthraquinone-based lyotropic liquid crystal or combination thereof.
4. A liquid crystal cell comprising a substrate, a liquid crystal layer and a guest-host polarizer as claimed in claim 1 .
5. The liquid crystal cell of claim 4 wherein the guest-host polarizer is arranged between the liquid crystal layer and the substrate.
6. A liquid crystal cell as claimed in claim 5 wherein at least one of a compensation layer, a retarder layer, a color filter layer and a viewing angle layer or other optical layer is arranged between the substrate and the liquid crystal layer.
7. A method of manufacturing a guest-host polarizer comprising an oriented polymer film including an oriented polymerized liquid crystal host and a dichroic light-absorbing guest dispersed and oriented in the host, the oriented polymer film having a dichroic ratio of about 15 or more, the method comprising:
providing a thin film of a polymerizable liquid crystal host and, dispersed therein, a dichroic light-absorbing guest;
orienting the polymerizable liquid crystal host and the dichroic light-absorbing guest to obtain an oriented thin film of oriented polymerizable liquid crystal host and a dichroic light-absorbing guest dispersed and oriented in the host, the oriented thin film having a dichroic ratio of about 15 or more;
polymerizing the polymerizable liquid crystal host in the oriented state to obtain an oriented polymer film including an oriented polymerized liquid crystal host and a dichroic light-absorbing guest dispersed and oriented in the host, the oriented polymer film having a dichroic ratio of about 15 or more, and the orientation of the oriented polymer film is or corresponds to the orientation of a smectic phase S x wherein the smectic phase S x is not smectic A phase or smectic C phase.