PURPOSE: To adjust easily the illuminance distribution pattern of a belt-shaped illumination area, by making the arrayed pattern in the longitudinal direction of the first slit member different from that concerning the second slit member.
CONSTITUTION: When slit members 1 and 2 are so overlapped that left edges of leftmost light transmitting parts 11 and 21 of slit members 1 and 2 are matched to each other, a width L3 of light transmitting areas 31 is decreased according as going toward the center in respect to arrayed patterns of light transmitting areas 31 and light shielding areas 32. When the second slit member is displaced slightly to the right relatively to the first slit member 1, the width of light transmitting areas 31 is increased according as going toward the center in respect to arrayed patterns of light transmitting areas 31 and light shielding areas 32. An illuminance distribution pattern formed on the rear face side of an adjuster is changed in accordance with the relative slide length of the second slit member 2 to the first slit member 1. Consequently, the illuminance distribution pattern of the illumination area is adjusted easily.
SATOMI AKIRA
IMAMURA KENJI
