Liquid crystal temperature control by resistive heating
AssigneePalo Alto Research Center Incorporated
InventorAlex Hegyi
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Abstract
An optical device includes a first transparent substrate having a first transparent electrode disposed on a surface of the first transparent substrate and a second substrate having a second electrode disposed on a surface of the second substrate and facing the first transparent electrode. A liquid-crystal (LC) material is sandwiched between the first and second electrodes such that a voltage applied between the first and second electrodes controls orientation of the liquid-crystal material. The device includes a control system that applies a current through at least one electrode of the first and second electrodes to resistively heat the LC material.
Claims20
A device comprising:
- a first transparent substrate;
- a first transparent electrode disposed on a surface of the first transparent substrate;
- a second substrate;
- a second electrode disposed on a surface of the second substrate facing the first transparent electrode;
- a liquid-crystal material disposed between the first and second electrodes such that a voltage applied between the first and second electrodes controls orientation of the liquid-crystal material;
- and
- a control system configured to apply an electrical current through at least one electrode of the first and second electrodes to resistively heat the liquid-crystal material,
- characterized in that the electrical current is selected based on thermal time constants of the at least one electrode, the liquid-crystal material, and at least a portion of the first transparent substrate and the second substrate.
A hyperspectral imaging system comprising:
- a first polarizer;
- a second polarizer;
- a liquid-crystal variable retarder disposed between the first polarizer and the second polarizer, the liquid-crystal retarder comprising:
- a first transparent substrate;
- a first transparent electrode disposed on a surface of the first transparent substrate;
- a second transparent electrode;
- a second transparent electrode disposed on a surface of the second transparent substrate facing the first transparent electrode;
- and
- liquid-crystal material disposed between the first electrode and the second electrode, the first and second electrodes arranged such that a voltage applied between the first electrode and the second electrode controls orientation of the liquid-crystal material and an electrical current applied through at least one electrode of the first and second electrodes resistively heats the liquid-crystal material;
- and
- an image sensor arranged to receive light from the second polarizer,
- characterized in that the electrical current is selected based on thermal time constants of the at least one electrode, the liquid-crystal material, and at least a portion of the first transparent substrate and the second substrate.
A method of controlling a liquid-crystal cell comprising a first transparent electrode, a second transparent electrode, and liquid-crystal material disposed between the first electrode and the second electrode, the method comprising:
- controlling orientation of the liquid-crystal material by controlling a voltage between the first electrode and the second electrode;
- and
- resistively heating the liquid-crystal material by controlling an electrical current through at least one electrode of the first and second electrodes,
- characterized in that the electrical current is selected based on thermal time constants of the at least one electrode, the liquid-crystal material, and at least a portion of the first transparent substrate and the second substrate.
Dependencies are inferred from the claim text.