The Visual Effects of Exposure to Electroluminescent Instrument Lighting

This report describes two experiments with electroluminescent aircraft instrument lighting. In the first experiment, white electroluminescent, green electroluminescent, and red incandescent lighting were compared for their effects on dark-crdapted. scotopic absolute and acuity thresholds. using a simulated T-38 instrument panel for light exposure. I n the second experiment, white, green, and yellow electroluminescent and red incandescent light were compared in terms of legibility of a transillumi-wted lettermuity chart. Exposure to red incandescent lighting at 0.05 f t. 4 produced the lowest absolutq and acuity thresholds, with white and green electroluminescent producing higher thresholds in that order. Although threshold differences between lighting colors were statistically significant. the absolute differences in visual sensitivity were small for practical purposes. Luminances required for equal legibility of transilluminated letters o f various sizes were about the same for red incandescent, and white, green, and yellow electroluminescent lamps. Electroluminescent lighting of aircraj? instruments is discussed. 1NTRODUCTlON The purpose of this investigation was to determine the effects of exposure to an electro-luminescent-lighted aircraft instrument panel on human dark-adapted vision, The research was prompted by concern with the color and type of aircraft instrument lighting that best ‘enables a pilot to detect dimly illuminated targets outside his aircraft at night. For this purpose, several colors of electroluminescent lighting were compared with aviation red incan-descent lighting. Visual factors considered were scotopic sensitivity, scotopic acuity, and instru-ment panel legibility. Aircraft illumination systems have generally depended on incandescent lamps mounted in flood or integral lighting fixtures, with illumi-nant color varying between unfiltered white, ultra-violet, red, and blue-filtered white (Bake