Patent Number: 6,166,858

Title: Image-forming optical system using prism elements

Abstract: A high-performance image-forming optical system made compact and thin by folding an optical path using reflecting surfaces arranged to minimize the number of reflections. The image-forming optical system has a first prism placed on the object side and a second prism placed on the image side and does not form an intermediate image. The first prism has a first surface through which a light beam enters the first prism, a second surface reflecting the incident light beam in the prism, a third surface reflecting the reflected light beam in the prism, and a fourth surface through which the light beam exits from the prism. At least one of the second and third surfaces has a rotationally asymmetric curved surface configuration that gives a power to a light beam and corrects aberrations due to decentration. The second prism has at least one reflecting surface that reflects a light beam in the prism. The reflecting surface has a rotationally asymmetric surface configuration that gives a power to a light beam and corrects aberrations due to decentration.

Inventors: Togino; Takayoshi (Hachioji, JP), Oode; Hisashi (Hachioji, JP)

Assignee: Olympus Optical Co., Ltd.

International Classification: G02B 17/08 (20060101); G02B 027/14 ()

Expiration Date: 12/26/2017