Further development of a self-referenced fiber optic temperature sensor using the contrast characteristics of an LCD segment

Julian Mason; Andreas T. Augousti

doi:10.1117/12.191856

1 November 1994 Further development of a self-referenced fiber optic temperature sensor using the contrast characteristics of an LCD segment

Julian Mason, Andreas T. Augousti

Author Affiliations +

Proceedings Volume 2292, Fiber Optic and Laser Sensors XII; (1994) https://doi.org/10.1117/12.191856
Event: SPIE's 1994 International Symposium on Optics, Imaging, and Instrumentation, 1994, San Diego, CA, United States

Abstract

The authors have previously reported the use of liquid crystals as transducing elements in novel configurations. The use of liquid crystals in these devices relies on the temperature dependence of their alignment and relaxation times when activated in an LCD, as opposed to their more conventional usage when it is their color change with temperature that is utilized. The liquid crystals in these latter instances have been thermotropic, and have not been activated in an electrical fashion. This paper reports the further development of a sensor which uses the temperature dependence of the activation voltage of the liquid crystals in an LCD. The device is self-referenced in that two time-multiplexed signals are produced when the LCD is alternately activated and inactivated. The output signal is a ratio of these two signals and the division is performed using a look-up table. The sensitivity of the system has been increased and additional features added to detect both damage to the probe head/optical fiber and excursion beyond the specific temperature range.

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Julian Mason and Andreas T. Augousti "Further development of a self-referenced fiber optic temperature sensor using the contrast characteristics of an LCD segment", Proc. SPIE 2292, Fiber Optic and Laser Sensors XII, (1 November 1994); https://doi.org/10.1117/12.191856

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