| 摘要 |
PURPOSE:To obtain a moire-free lens by employing a polygonal plane shape for fractionized unit segments of a spot convergent type Fresnel lens which has grades cut in a transparent substrate while the curved surface of the lens is fractionized in the optical-axis direction. CONSTITUTION:The Fresnel lens is fractionized in a mosaic shape so that a linear pattern cut in the Fresnel lens is not superposed upon the linear pattern of an array of unit lens of a micro lens in parallel, and plane shape of the frictionized unit segments is preferably reactangular or square. Then, the linear pattern is allowed to cross the linear pattern of the micro lens array at some angle (45 deg. in a figure) without being superposed in parallel, obtaining a high-contrast screen which eliminates moire. |
