Patent ID: 8292438

Claim:
A projection image display device comprising: a light source; an illumination optical system that uniformly irradiates a surface of an image modulating element with a light beam emitted from the light source, the surface of the image modulating element being a primary image surface; and a projection optical system that performs extended projection at a secondary image surface on image information provided at the primary image surface and modulated by the image modulating element, wherein the projection optical system includes a first optical system having a positive refractive power, and a second optical system having a concave reflecting surface, and wherein the first optical system has a common optical axis at which all optical components of the first optical system have rotationally symmetric surfaces, and a screen shift function that causes the secondary image surface to be moved by moving at least one of the optical components of the first optical system substantially perpendicularly to the optical axis, wherein a refractive power Φs of the at least one of the optical components and a refractive power Φ 1 of the first optical system during standard projection satisfy Conditional Expression (1): 0.2<|φ s/φ 1|<1.2 (1).