Large-aperture aspheric single lens

Abstract

Abstract PURPOSE: To obtain a large-aperture aplanat with diffraction limit which is used to an objective lens for reproduction of video disk, etc., by satisfying the prescribed conditions for an aspherical single lens both the 1st and 2nd faces of which have the positive refractive power. CONSTITUTION: The conditions of expressions (1)W(3) are satisfied for a single lens composed of an aspherical surface both the 1st and 2nd faces have the positive refractive power. In this case, (x) is the distance between a point on an aspherical surface having the height (h) from the optical axis, (c) is the curvature of the aspheric apex, (k) is a conical constant, A 21 (i: ≥2 integer) is the aspheric coefficient, R 1 and K 1 are the curvature radius and the conical coefficient of the 1st face, (f) is the focal distance, and (n) is a refractive index, respectively. In such way, a large-aperture aplanat is obtained with diffraction limit. COPYRIGHT: (C)1982,JPO&Japio

Inventors

• 👤 Norikazu Arai
• 👤 Shozo Ishiyama
• 👤 Tadashi Kojima

Bibliographic Details