Patent ID: 8643795

Claim:
A thermoreflective or thermoabsorptive filter comprising a diffractive-type polarizer having a first index of refraction; a thermotropic material adjacent to the diffractive-type polarizer; wherein the thermotropic material is configured such that below a threshold temperature the thermotropic material has a second index of refraction that is substantially similar to the first index of refraction such that incident light is not substantially refracted at an interface between the diffractive-type polarizer and the thermotropic material and thus the filter is largely transparent; and the thermotropic material is configured such that above the threshold temperature the thermotropic material has a third index of refraction that is substantially different from the first index of refraction such that incident light is substantially refracted at the interface between the diffractive-type polarizer and the thermotropic material and thus the filter is attenuating to the incident light.