Fresnel lens

Abstract

Abstract PURPOSE:To prevent the occurrence of a rainblow on the screen surface, by lengthening the focal length of the lens gradually toward the outside edge part from the lens center. CONSTITUTION:Prism faces in the form of concentric circles formed on one face of the molding mold are transferred and formed on one face of the transparent plastic to obtain a Fresnel lens, and in this case, lens tilt angle theta is made small in the outside edge part as shown by the solid line so that the focal length of the light, which passes through each prism and is refracted, for the optical axis of the center of the lens becomes longer gradually toward the outside edge part from the center. As a result, the light incident to eyes of the observer is not incident as separated colors apparently, so that the occurrence of a rainblow on the screen surface is prevented, and the observer does not feel fatigued due to long-time observation.

Inventors

• 👤 Yasutomo Funakoshi
• 👤 Tamotsu Wakahata

Bibliographic Details