Temperature activated optical films
First Claim
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 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, the first and second optical axis are substantially parallel and the first and second refractive indices are substantially equal, the third refractive index differ from the second refractive index and from the first refractive index; and
wherein the optical thickness of each of the first layer is equal to ¼
times the predetermined wavelength and the optical thickness of each of the second layer when the temperature is above the Tc is equal to ¼
times the predetermined wavelength.
4 Assignments
0 Petitions
Accused Products
Abstract
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.
-
Citations
23 Claims
-
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 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, the first and second optical axis are substantially parallel and the first and second refractive indices are substantially equal, the third refractive index differ from the second refractive index and from the first refractive index; and wherein the optical thickness of each of the first layer is equal to ¼
times the predetermined wavelength and the optical thickness of each of the second layer when the temperature is above the Tc is equal to ¼
times the predetermined wavelength. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
-
-
17. A method of manufacturing multilayer optical structure, comprising:
-
providing a polymer layer;
deploying a mesh on the polymer layer, wherein the polymer mesh is substantially uniform in height and partition the layer into sections;depositing a layer of liquid crystal mixture into the sections on the polymer layer forming a liquid crystal layer; applying a top layer sealing liquid crystal layer; and stretching the formed polymer layer and liquid crystal layer structure changing refractive indices along the stretching direction of the polymer layers to a predetermined value and to align liquid crystal to the stretch direction below a characteristic transition temperature. - View Dependent Claims (18, 19, 20, 21, 22)
-
-
23. A multilayer dielectric optical system, comprising:
-
a transparent substrate; a plurality of dielectric pairs, wherein each pair comprise a first layer of a first optical material having a first refractive index and a liquid crystal layers having a third isotropic refractive index when temperature is above transition, optical thickness of the first layer equals to the optical thickness of the liquid crystal layer equals to ¼
of a predetermined wavelength λ
0, wherein the number of dielectric pairs is between 1 to 500; andthe Optical thickness of each adjacent pair is in accordance to the formula;
dN+1=r dN
first layer d1=¼
λ
0where dN is the optical thickness of Nth pair, it is the two times the optical thickness of each layer in the pair and r is a numerical number between 0.85 to 0.999.
-
Specification