Accession Number : ADA296455

Title :   The Liquid Crystal Smart Reflector.

Corporate Author : BRANDEIS UNIV WALTHAM MA DEPT OF PHYSICS

Personal Author(s) : Chang, Ching-Chao ; Lonberg, Franklin ; Meyer, Robert B.

Report Date : 08 JUN 1994

Pagination or Media Count : 11

Abstract : We report the first demonstration of a liquid crystal smart reflector. This is an optical reflector based on cholesteric liquid crystals, in which as light intensity increases, so does the reflectivity. This is achieved by having an optically absorbing layer behind the cholesteric liquid crystal layer, and in thermal contact with it, acting as a sensor of light. The liquid crystal is chosen to have a highly temperature dependent helix pitch, so that when it is heated by the absorption of light in the sensor layer, its pitch changes rapidly. This is the computational function of the device. The change in helix pitch results in an increase in reflectivity of light, the actuator function of the device. The increased reflectivity stabilizes the device by negative feedback, keeping it at an effective operating point. We report experiments and computer simulations of the device demonstrating its successful function. (MM)

Descriptors :   *LIQUID CRYSTALS, *LIGHT TRANSMISSION, *REFLECTORS, THERMAL PROPERTIES, COMPUTERIZED SIMULATION, OPTICAL PROPERTIES, SYMPOSIA, DETECTORS, INTENSITY, OPTICAL MATERIALS, FEEDBACK, ABSORPTION SPECTRA, REFLECTIVITY, HELIXES.

Subject Categories : Physical Chemistry
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE