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US 2019/0162989 A1Published application
Thermally and electrically switched windows for combined visible and infrared light attenuation
AssigneeRavenBrick LLC
InventorsWilder IGLESIAS, Piotr POPOV
Life of this patent
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Abstract
Thermally and electrically driven dynamic filters for smart windows are configured to filter electromagnetic radiation in the infrared range of wavelengths. Some thermochromic filters embodiments are configured to filter both electromagnetic radiation in the infrared range of wavelengths and electromagnetic radiation in the visible range of wavelengths.
Claims20
A filter assembly, comprising:
- a first chiral nematic liquid crystal layer having a first handedness;
- a second chiral nematic liquid crystal layer having a second handedness;
- and
- a nematic liquid crystal layer having a nematic-isotropic clearing point temperature chosen to be within the working temperature of the filter positioned between the first and second chiral nematic liquid crystal layers;
- wherein
- in the nematic state,
- the first chiral nematic liquid crystal layer blocks a first half of infrared light incident on the filter as infrared light of a first circular polarization and transmits a second half of the incident infrared light as polarized light of a second circular polarization to the nematic liquid crystal layer;
- and
- the nematic liquid crystal layer functions as a half wave plate and inverts the transmitted infrared light into light of the first circular polarization, which is then transmitted through the second chiral nematic liquid crystal layer;
- and
- in the isotropic state,
- the first chiral nematic liquid crystal layer blocks a first half of infrared light incident on the filter as light of a first circular polarization and transmits a second half of the incident infrared light as polarized light of a second circular polarization to the nematic liquid crystal layer;
- and
- the half-wave plate function of the nematic liquid crystal layer vanishes and the transmitted infrared light is blocked by the second chiral nematic liquid crystal layer as infrared light of a second circular polarization.
11 more elements
A filter assembly, comprising:
- a first chiral nematic liquid crystal layer having a first handedness;
- a second chiral nematic liquid crystal layer having a second handedness;
- and
- a nematic liquid crystal layer having a nematic-isotropic clearing point temperature chosen to be outside of the working temperature of the filter positioned between the first and second chiral nematic liquid crystal layers;
- a transparent conducting layer positioned adjacent to the nematic liquid crystal layer;
- wherein
- in a first voltage state applied to the transparent conducting layer,
- the first chiral nematic liquid crystal layer blocks a first half of infrared light incident on the filter as light of a first circular polarization and transmits a second half of the incident infrared light as polarized infrared light of a second circular polarization to the nematic liquid crystal layer;
- and
- the nematic liquid crystal layer functions as a half wave plate and inverts the transmitted infrared light into infrared light of the first circular polarization, which is then transmitted through the second chiral nematic liquid crystal layer;
- and
- in a second voltage state applied to the transparent conducting layer,
- the first chiral nematic liquid crystal layer blocks a first half of infrared light incident on the filter as infrared light of a first circular polarization and transmits a second half of the incident infrared light as polarized infrared light of a second circular polarization to the nematic liquid crystal layer;
- and
- the half-wave plate function of the nematic liquid crystal layer vanishes and the transmitted infrared light is blocked by the second chiral nematic liquid crystal layer as infrared light of a second circular polarization.
12 more elements
Dependencies are inferred from the claim text.