Oblon,
Method of mixed illumination
 Beautifully and balanced colored shadows can be cast of an object by using a lamp for emitting colored light in the range yellow to red, a lamp for emitting green colored light and a lamp for emitting colored light in the range violet to blue to give intensity ratios of illumination in the ranges of EQU 0.05 .ltoreq. I.sub.R /(I.sub.R + I.sub.G + I.sub.B) .ltoreq. 0.85; EQU 0.05 .ltoreq. i.sub.g /(i.sub.r + i.sub.g + i.sub.b) .ltoreq. 0.8; and EQU 0.02 .ltoreq. I.sub.B /(I.sub.R + I.sub.G + I.sub.B) .ltoreq. 0.8 wherein I.sub.R designates an intensity of illumination caused by irradiating with only the lamp in the R group the shadow of an object cast by both of the lights of the lamps in the G group and the B group; I.sub.G designates an intensity of illumination caused by irradiating with only the lamp in the G group the shadow of the object cast by both of the lights of the lamps in the R group and the B group and I.sub.B designates an intensity of illumination caused by irradiating with only the lamp in the B group the combination of the shadow of the object cast by the light of the lamp in the R group and the shadow of another object cast by the light of the lamp in the G group. 
Mitsubishi Denki Kabushiki Kaisha
F
F21W
additional
Koichiro Makoto Michihiro Masato Yasushi Osamu Hidetoshi
Maeyama Yamanoshita Tsuchihashi Saito Uchida Myodo Katsura