FLAT PLATE MICROLENS ARRAY WITH REFLECTION SURFACE AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To make it possible to change an optical path length without affecting optical characteristics by forming a surface formed with lenses as a substrate front surface and the surface on the side opposite thereto as a substrate rear surface and reflecting the incident light from the substrate front surface along the optical axis in a direction exclusive of the optical axis direction by the substrate rear surface. SOLUTION: The surface of this flat plate microlens 104 on which the microlenses 101 are formed within a transparent substrate, for example, a glass substrate 100, is formed as the substrate front surface 500 and the surface on the side opposite thereto is formed as the substrate rear surface 501. In such a case, the substrate rear surface 501 is sloped at an inclination ofθwith the optical axis of the microlenses 101. The substrate rear surface 501 has a structure to reflect the incident light from the substrate front surface 500 along the optical axis toward the front surface 502 exclusive of the direction of the optical axis. The angle 6 that the refractive indices 501 forms with the optical axis of the microlenses 101 is so selected as to attain the angle satisfying the conditionθ=cos<-1> (1/n) under which the incident light is totally reflected when the circumference of the flat plate microlens is formed of the atm. air and the refractive index of the glass substrate is defined as a real number (n) larger than 1.