| 摘要 |
PURPOSE:To obtain an image plane having extremely high contrast even under bright light, by forming a plastic plate body contg. a specific weight part of a light scattering material having specific grain sizes into such shape of the outside contour curve of a section intersecting orthogonally with the axial line direction of convex cylindrical lenses on one surface thereof that the ratio between the long axis and the short axis coincides with the curve on the long axial end side of the ellipse within a specific range and forming a light abosrbing film only on the non-condensing part of the other surface. CONSTITUTION:A sheet contains 0.5-5pts.wt. a light scattering material having about 0.5-30mu grain sizes in 100pts.wt. a plastic having the power for forming a transparent plastic plate body. The convex cylindrical lens group formed on the one surface of the sheet is made into the shape wherein the shape of the external contour curve in the section intersecting orthogonally with the axial line direction of the convex cylindrical lenses coincides with the curve on the long axis end side of the ellipse of which the ratio between the long axis and the short axis is in an 11X21/2/10-9X21/2/10:1 range; therefore, the spherical aberration of the convex cylindrical lens is virtually eliminated. Therefore, the area in the non-condensing part (n) in the other surface S2 is made considerably larger as compared to conventional sheets and the area of the coated film C by a light absorber is formed largely. |
