| 摘要 |
PURPOSE:To realize smooth diaphragm action without affecting a light shielding plate by using strong ultraviolet rays as exposing light by providing a projection part on the sliding surfaces of plural light shielding plates and bringing the light shielding plates into fine contact with each other through the projection parts. CONSTITUTION:An oscillating element 10 functioning as the projection part such as a piezoelectric element is fixed on the sliding surface of the light shielding plate 1a, and comes in point-contact with the light shielding plate so that a very small area being only the tip of the element 10 may come in contact with the light shielding plate 1b. A very small gap is formed between the light shielding plates 1a and 1b other than the contact part. The element 10 is oscillated in an up-and-down direction with a specified frequency through a lead wire 11 according to the command of an oscillation control part. In such a case, the element 10 and the lead wire 11 are positioned in an area where a return luminous flux is not made incident. Thus, a specified aperture diameter is obtained by smooth turning action. |
