초록 ▼

The present invention discloses a multilayer dielectric optical structure wherein one of the optical materials in the multilayer structure shows an optically isotropic state above and a birefringent state below a characteristic temperature Tc near the room temperature. The optical structure reflects

The present invention discloses a multilayer dielectric optical structure wherein one of the optical materials in the multilayer structure shows an optically isotropic state above and a birefringent state below a characteristic temperature Tc near the room temperature. The optical structure reflects a predetermined wavelength range of electromagnetic radiation above the Tc but allow the same to transmit through below the Tc. The predetermined wavelength can be the near infrared radiation from 700 nm to 2500 nm, and the optical structure rejects solar heat in warm summer days but admits the same to interior on a colder winter day.

대표청구항 ▼

What is claimed is: 1. A multilayer dielectric optical structure, for selectively reflecting a predetermined wavelength, comprising:a transparent substrate;a plurality of alternating first layers and second layers on the substrate, wherein the first layers comprise a first optical material having a

What is claimed is: 1. A multilayer dielectric optical structure, for selectively reflecting a predetermined wavelength, comprising:a transparent substrate;a plurality of alternating first layers and second layers on the substrate, wherein the first layers comprise a first optical material having a first optical axis and a first refractive index along the first optical axis, and wherein the second layers comprise a second optical material having a second optical axis and a second refractive index along the second optical axis below a characteristic transition temperature (Tc) and a third refractive index above the Tc, wherein the second optical material includes a liquid crystal material having an isotropic-to-ordered state transition temperature between 15 and 35 degrees Celsius, wherein the first and second optical axes are substantially parallel and the first and second refractive indices are substantially equal, and wherein the third refractive index differs from the second refractive index and from the first refractive index; andwherein the optical thickness of each of the first layers is equal to ¼ times the predetermined wavelength and the optical thickness of each of the second layers is equal to ¼ times the predetermined wavelength when the temperature is above the Tc.