Abstract: A discharge lamp having a large light output and a stable discharge. On an external surface of a cylindrical glass bulb enclosing a rare gas such as xenon, a pair of beltlike electrodes are mounted so as to face each other. A light output part is provided between the electrodes, and the electrodes are situated close to each other on the opposite side to the light output part. An image display device is constituted by arranging a plurality of the discharge lamps.

Abstract: A surface luminous lighting unit has a light panel comprising a plurality of light guiding plates laminated in different lengths. The longer side of the light panel is made shorter than the distance between filaments of a lamp, and longer than the distance between the portions where a luminance of the lamp is equal to 75% of the maximum luminance of the lamp. The surface luminous lighting unit comprises a light guide which comprises a plurality of light guiding plates in different length laminated in such a manner that the sides of those plates where light enters are made level with each other, where the other sides thereof are arranged in a step-like. A linear light source is affixed to the light entering side of the light guide, and a reflector is affixed to the light exiting side of the light guide in such a manner as to extend thereover.

Abstract: A new type of display unit is provided. A light emitting body such as a fluorescent lamp is disposed behind an elongated display panel. The middle section of the fluorescent lamp extends parallel to the elongated display panel to face it from end to end. The opposite ends of the lamp are bent if necessary.

Abstract: Beautifully and balanced colored shadows can be imparted by arranging an R unit for light sources for yellow to red; a G unit for light sources for green and a B unit for light sources for violet to blue with each predetermined space wherein each unit comprises a plurality of light sources in each group adjacent each other.

Abstract: Beautifully and balancedly colored shadows can be imparted by arranging color lamps in three R, G and B groups, illuminating an object to obtain colored shadows of the object to give the ratios of illuminances by the color light lamps; ##EQU1## in a range surrounded by the following ratios of j-k-l-m-n-e-f-j in the triangular coordinate of FIG. 2 wherein I.sub.R designates an illuminance by only the lamp in the R group; I.sub.G designates an illuminance by only the lamp in the G group and I.sub.B designates an illuminance by only the lamp in the B group.______________________________________ Symbol i.sub.R i.sub.G i.sub.B ______________________________________ j 0.78 0.2 0.02 k 0.65 0.2 0.15 l 0.65 0.05 0.3 m 0.55 0.05 0.4 n 0.2 0.4 0.4 e 0.05 0.8 0.15 f 0.18 0.8 0.

Abstract: Beautifully and balancedly colored shadows can be imparted by arranging color lamps in three R, G and B groups and a white light lamp for white light (W group), illuminating objects to obtain colored shadows of the objects, giving the ratio of illuminance by the white light lamp: ##EQU1## wherein I.sub.W designates an illuminance at the part illuminated by only the white light lamp, and also the illuminance in the shadows to the lights of the lamps of the three R, G and B groups; and I.sub.R designates an illuminance at the part illuminated by only the lamp of the R group in the shadow of the object to both of the lights of the lamps of the G group and the B group; I.sub.G designates an illuminance at the part illuminated by only the lamp in the G group in the shadow of the object to both of the lights of the lamps in the R group and the B group and I.sub.

Abstract: 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 of0.05 .ltoreq. I.sub.R /(I.sub.R + I.sub.G + I.sub.B) .ltoreq. 0.85;0.05 .ltoreq. i.sub.g /(i.sub.r + i.sub.g + i.sub.b) .ltoreq. 0.8; and0.02 .ltoreq. I.sub.B /(I.sub.R + I.sub.G + I.sub.B) .ltoreq. 0.8wherein 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.