| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a belt type dimming control unit easy to carry out fine adjustment. SOLUTION: This dimming control unit is produced by turning a soft belt 1 made of urethane or rubber base material around the circumference of a plurality of rotatable guides 2, 3, 4, 5 and carries out dimming control by rotating the belt 1 by sliding operation of the belt 1. In this case, friction force is so applied as not to rotate at least one guide 3 by operational force at a prescribed level or lower and as to rotate the guide by operational force over the prescribed level or higher.</p> |
