Projection optical system, projection-type image display device, imaging device, and method of manufacturing optical element

Abstract

The invention provides a projection optical system, a projection-type image display device, an imaging device, and a method of manufacturing an optical element. The projection optical system has an optical element in which two members having different refractive indexes are bonded to each other, and is easy to manufacture. The projection optical system (3B) comprises a first optical system (31) and a second optical system (32) from a de-magnifying side, and an intermediate image (33) is formed between a de-magnifying side image formation plane and a magnifying-side image formation plane. The second optical system (32) is an optical element (35A). The optical element (35A) has a first transmissive surface (41), a reflective surface (42), and a second transmissive surface (43) from the de-magnifying side to a magnifying side. The optical element (35A) has a first part and a second part having a refractive index different from that of the first part on the optical path of light passing through the optical element (35A). The second part is spherical, and the first part is in close contact with the outer peripheral surface of the second part.

Description

technical field [0001] The present invention relates to production of a projection optical system having a concave reflective surface on the magnification side of an intermediate image, a projection type image display device having the projection optical system, an imaging device having the projection optical system, and an optical element having a concave reflective surface method. Background technique [0002] Patent Document 1 describes a projection-type image display device that magnifies and projects a projection image formed by an image forming unit using a projection optical system. The projection optical system of this document is composed of a first optical system and a second optical system in order from the reduction side toward the enlargement side. The first optical system has a refractive optical system. The second optical system is constituted by a reflective mirror having a concave reflective surface. The image forming unit has a light source and a light v...

AI Technical Summary

Problems solved by technology

Therefore, with regard to a projection optical system having only a concave reflector on the magnification side of the intermediate image, there is a problem that the reflector tends to increase in size when the projection distance is shortened.

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