| 摘要 |
PURPOSE:To perform switching between a soft and a sharp image by arranging a liquid crystal cell which has a liquid crystal layer between orienting films and a polarizing plate in an optical system, and controlling the axis of polarization of incident light to the liquid crystal layer or projection light from the liquid crystal layer and decreasing the sharpness of an image formed by the optical system. CONSTITUTION:Homogeneous orienting films 18 and 19 which orient liquid crystal molecules 22 horizontally and homeotropic orienting films 20 and 21 which orient them vertically are formed on glass substrates 16 and 17 opposite each other, and the liquid crystal layer 23 is sandwiched between them to constitute the liquid crystal cell 15. The liquid crystal optical phase filter consisting of this liquid crystal cell 15 and the polarizing plate 25 is used to decrease the image sharpness over the entire range of visible light; when a soft photograph is taken, the polarizing plate 25 is rotated on the liquid crystal cell 15 to obtain a desired soft quantity according to the quantity of rotation and when a sharp photograph is taken, the axis of polarization of the polarizing plate 25 is set at right angles to the orientation direction of liquid crystal molecules in an area of homeotropic orientation. Consequently, the switching between the soft image and sharp image is performed without impressing any electric field.
|
