| 摘要 |
<p>PURPOSE:To remove the restriction of a wavelength range and to increase the ratio of light based upon the ON and OFF of light by rotating a movable thin film upon a torsion shaft by electrostatic power to change an optical path and control the quantity of light. CONSTITUTION:When a voltage Vf s impressed between a common electrode 22 and the movable thin film 25, the thin film 25 is attracted to the electrode side 22 by the electrostatic power applied between positive electric charge impressed to the thin film 25 and negative charge generated in the thin film 25. Since only one side of the electrode 22 is opposed to a supporting shaft to be the tortion shaft 26 of the thin film 25, moment is generated around the shaft 26 of the thin film 25 and the thin film 25 is rotated. When a potential difference between the electrode 22 and the thin film 25 is turned to '0', the moment to be applied to the thin film 25 is removed and the thin film 25 is returned to the original balanced position. When the thin film 25 is located on the balanced position, an optical beam F1 is reflected by the thin film 25 and the reflected optical beam is transmitted through an upper base plate 20 to expose a photosensitive body. When the thin film 25 is located on a rotated position, the reflected optical beam is not transmitted through the base plate 20 and the photosensitive body is not exposed.</p> |
