Thermotropic optical shutter incorporating coatable polarizers
AssigneeRavenBrick LLC
InventorWil McCarthy
Life of this patent
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Abstract
A thermotropic optical shutter device incorporates coatable, thin-film polarizers with a thermotropic depolarizer. The coatable polarizers provide a mechanism for adjusting the polarizer properties (i.e., absorption, reflection, or diffusion) by changing the thickness of the coating. For example, a thicker film may have a higher relative polarizing efficiency while a thinner film may have a lower relative polarizing efficiency. Using the same base materials and manufacturing process, the contrast ratio and other properties of a thermotropic or thermochromic shutter device (e.g., a liquid crystal-based smart window film) may be adjusted in real time on the manufacturing line.
Claims15
A thermotropic shutter device comprising
- a first transparent substrate;
- a second transparent substrate;
- one or more thin film polarizing coatings applied to at least the first transparent substrate, the one or more polarizing coatings acting as a linear polarizer when applied to at least the first transparent substrate;
- and
- a thermotropic liquid crystal depolarizer supported by the first and second transparent substrates that rotates a polarity of light perpendicular to that of the thin film polarizing coatings on the first substrate and passing therethrough to a perpendicular polarity when in a twisted nematic state;
- wherein
- in a cold state the thermotropic liquid crystal depolarizer is in the twisted nematic state and the device exhibits a high transmission within a given wavelength band, and
- in a hot state the thermotropic liquid crystal depolarizer is not in the twisted nematic state and the device exhibits a low transmission within a given wavelength band.
A method for altering one or more of absorption, reflection, diffusion, polarizing efficiency, contrast ratio, or visible light transmission properties of a thermotropic shutter device, wherein the thermotropic shutter device comprises a first transparent substrate, a second transparent substrate, one or more thin film polarizing coatings that are applied to at least the first transparent substrate and that act as a linear polarizer when applied to at least the first transparent substrate, and a thermotropic liquid crystal depolarizer supported by the first and second transparent substrates that rotates a polarity of light perpendicular to that of the thin film linear polarizing coating on the first substrate and passing therethrough to a perpendicular polarity when in a twisted nematic state, the method comprising
- adjusting a thickness of at least one of the thin film polarizing coatings while applying the thin film polarizing coatings to at least the first transparent substrate.
A method for altering one or more of absorption, reflection, diffusion, polarizing efficiency, contrast ratio, visible light transmission, bandwidth, center wavelength, UV resistance, chemical resistance, adhesion, or temperature stability properties of a thermotropic shutter device, wherein the thermotropic shutter device comprises a first transparent substrate, a second transparent substrate, one or more thin film polarizing coatings that are applied to at least the first transparent substrates and that act as a linear polarizer when applied to at least the first transparent substrate, and a thermotropic liquid crystal depolarizer supported by the first and second transparent substrates that rotates a polarity of light perpendicular to that of the thin film linear polarizing coating on the first substrate and passing therethrough to a perpendicular polarity when in a twisted nematic state, the method comprising
- adjusting a composition of at least one of the thin film polarizing coatings before applying at least one of the thin film polarizing coatings onto the transparent substrate.
A method on a manufacturing line for adjusting properties of a thermotropic optical filter incorporating a thermotropic liquid crystal depolarizer supported on a first transparent substrate, the method comprising
- incorporating a coating station that deposits a thin film linear polarizing coating on the first transparent substrate, wherein the thin film polarizing coating acts as a linear polarizer when applied to at least the first transparent substrate, and the thermotropic liquid crystal depolarizer rotates a polarity of light perpendicular to that of the thin film linear polarizing coating on the first transparent substrate and passing therethrough to a perpendicular polarity when in a twisted nematic state;
- adjusting one or more of a thickness, composition, or coating condition of the thin film polarizing coating to thereby adjust one or more of an absorption, refection, or diffusion parameter of the polarizing coating;
- applying the thermotropic liquid crystal depolarizer on the thin film polarizer coating;
- placing a second transparent substrate on the thermotropic liquid crystal depolarizer;
- and
- sealing the first and second transparent substrates together to form the thermotropic optical filter.
Dependencies are inferred from the claim text.