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Proceedings Paper

Dynamic heater for display elements
Author(s): Brian P. Dehmlow; Gary D. Bishop; Martin J. Steffensmeier; James D. Sampica; Mark C. Skarohlid
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Paper Abstract

Liquid crystal display (LCD) deliver optimal performance when the entire display surface is isothermal and at a controllable temperature. This condition creates uniform electro-optical properties within the liquid crystal layer. This paper describes a dynamic, multicontact heater system that actively compensates for uneven heat loads, thereby creating the desired isothermal condition. The heater system includes a uniform resistive sheet, with multiple electrical contacts around the perimeter. A switch network connects each heater contact to a power supply, ground potential, or a high impedance. A microprocessor monitors the display temperature, and detects non-uniformity, and selectively applies heat to cold areas of the display. The dynamic heater system employs a variety of heating patterns to create the desired isothermal condition.Heating patterns vary in duration, power applied, and location on the display face. The microprocessor control loop can also detect and isolate faulty drive elements, and compensate for non- uniformity in the heater itself. The heater prevents stress- induced delaminations, mechanical distortions, and stress- induced birefringence in optical components. Test results indicate that a dynamic heater can be beneficial in the thermal design of LCD products.

Paper Details

Date Published: 1 July 1997
PDF: 9 pages
Proc. SPIE 3057, Cockpit Displays IV: Flat Panel Displays for Defense Applications, (1 July 1997); doi: 10.1117/12.276978
Show Author Affiliations
Brian P. Dehmlow, Rockwell Corp. (United States)
Gary D. Bishop, Rockwell Corp. (United States)
Martin J. Steffensmeier, Rockwell Corp. (United States)
James D. Sampica, Rockwell Corp. (United States)
Mark C. Skarohlid, Rockwell Corp. (United States)


Published in SPIE Proceedings Vol. 3057:
Cockpit Displays IV: Flat Panel Displays for Defense Applications
Darrel G. Hopper, Editor(s)

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