| 摘要 |
PURPOSE:To obtain high contrast by providing the shape of a renticular lens on one surface of a transparent substrate and the shape of a circular Fresnel lens on the other surface and providing light shielding parts by projecting the same from the projecting parts of the circular Fresnel lens. CONSTITUTION:A transmission type screen 1 is provided with a renticular lens surface 3 on one side of a substrate 2, and a circular Fresnel lens surface 4 on the other side. Further, projecting parts 5 are provided on the surface 4 and light shielding parts 6 on the parts 5. A sheet 3 is extruded with an extruder 7 by a melt extrusion method for resins and the shapes of the lenses 3, 4 are applied successively in the extruded sheet by using a die roll 9 formed with the inverse type of the lens 3 on the surface and a die roll 10 having the inverse type shape of the lens 4 and recesses deeper than the recesses of the inverse type shape of the lens 4. When such screen is viewed from an observer, the reflection of room lights, etc. is prevented, the unnecessary light brought by projected rays is shielded and the images of high contrast are obtained. |
