| 摘要 |
Apparatus for controlling reflected radiant energy to progressively vary distribution of the reflected radiant energy between spot and flood configurations comprises a housing body having a reflector surface, a lamp mounted in the housing body at the focal point of the reflector surface, and a dual light transmitting unit supported at an outer side of the housing body. The dual light transmitting unit includes a light transmitting disk component of circular shape fixed in abutting relation to the housing body, and a light transmitting disk cover component mounted for rotative movement about the central axis of the housing body and against the light transmitting disk. The light transmitting disk component is of generally circular shape and has an inner portion removed to form a substantially semi-circular opening. A remaining inner portion of the disk is formed with truncated arcuate mating portions which are light refracting and which present substantially V-shaped surfaces whose crests occur in concentrically spaced apart relationship to one another. The term "truncated" as herein employed is intended to define arcuate mating portions of limited annular extent. The rotatably mounted disk cover component is cylindrical in shape and has an end wall formed at an inner portion thereof with truncated arcuate mating portions also of light refracting character. These mating portions have substantially V-shaped surfaces which are complementary to the V-shaped surfaces of the disk component. A remaining inner portion of the end wall of the disk cover component is planar and of substantially semi-circular shape similar to the semi-circular opening in the disk component. The two sets of V-shaped surfaces are slidably engagable with one another. In a preferred embodiment, the openings in the light transmitting disk component and the planar portion of the end wall of the disk cover component are slightly less in circumferential extent than 180 DEG to insure that some part of the truncated arcuate mating portions are always in a position of engagement, and thus loss of register between the mating portions of the two components is avoided.
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