Process for producing a gradient index optical element

Abstract

A gradient index optical element is disclosed which comprises a surface perpendicular to an optical axis, this surface having points of equal refractive index whose connection provides substantially elliptic lines. This gradient index optical element can be produced, for example, by first pouring a raw material sol into a vessel suited for preparing a rodlike base material comprising a surface perpendicular to its lengthwise direction, said surface having the shape of a rectangle, a rhombus or a polygon symmetrical with respect to its center of gravity, each as is, or having a rounded or elliptical corner subsequently converting the sol to a gel, then subjecting the gel to distribution providing treatment and finally drying and firing the distribution providing gel. A gradient index optical element having, along its X- and Y-directions, refractive index distribution profiles different from each other can be produced at low cost, which permits one construct an optical system suitable for use in a technique of effecting image compression along a lateral direction and which attains a substantial miniaturization of a lens system, for example, a TV lens system.