LIGHT GUIDE TYPE LENS

摘要

PURPOSE:To form a lens in an accurate shape by forming a groove in each zone of a Fresnel lens so that the groove increases in depth and decreases in maximum length outwardly from an optical axis. CONSTITUTION:The Fresnel lens 30 having grooves which narrow down in width outwardly from the optical axis Z and have the width of a square-low distribution in the direction of the optical axis are formed in a light guide layer 23 formed on a substrate 21 across a buffer layer 22. A groove 32 in each zone decreases in maximum length and increases in depth outwardly from the optical axis. Therefore, zones closer to the outside have less effective refractive indexes and the shapes of the grooves do not become sharp, so that the lens is formed in the accurate shape in accordance with a designed pattern.