Light Generator for Various Waveform

Abstract

Experimental equipment by which various waveform of light can be generated has been developed for the psychophysical research on human visual temporal characteristics. For the light source of the equipment, electrodeless fluorescent lamps using short persistence phosphors driven by UHF electromagnetic wave are employed. The various waveform consisting of sequential short light pulses of more than 250 microseconds long, is generated by a typical feedback control in which the waveform of the UHF signal is modified temporally, based on the result of the sequential comparison between the measured intensity of the light output from the fluorescent lamps and the value of the waveform data. With the above mentioned control technique, the performance of the system realized is: circular light stimuli of 200mm diameter, the maximum luminance of 2000 cd/m²; the luminous uniformity, 0.8 (minimum/maximum); light color of white (correlated color temperature 5400K).