Patent ID: 9523908
Filing Date: 2016-12-20
CPC Classification: G02B,G03B

Claim Text:
1. An image projection apparatus, comprising: a projection optical system including one or more lenses, a concave mirror, and a plane mirror that are provided in order from a light incidence side on which incident light is incident, and configured to project an image using the incident light, wherein the one or more lenses are configured to form an intermediate-focused image on a near side of the concave mirror, and the plane mirror has an aspect ratio of 1.9 or more; and a transparent flat plate on an optical path connecting the concave mirror and the plane mirror, wherein the one or more lenses configure a symmetric optical system disposed on an optical axis, and wherein a distance, at which each of a passing beam centroid position on the light incidence side of the transparent flat plate and a passing beam centroid position on a light emission side of the transparent flat plate are disposed from the optical axis of the one or more lenses, is based on a focal distance of the projection optical system.