Patent ID: 8142032

Claim:
An optical system unit for projecting images, comprising: a light source-side optical system having a light smoothing unit for uniformly distributing an intensity of incident light and emitting the distributed light; a display device for forming an image by reflected light; and a projection-side optical system, whereby a light beam emitted from a light source unit is shone onto the display device via the light source-side optical system so as to form an image by the display device, and the formed image is projected onto a screen via the projection-side optical system, wherein the light smoothing unit is formed into a substantially truncated quadrangular pyramid such that upper, lower, left and right sides thereof are light reflection surfaces, an incident side thereof is formed into a square, and an emitting side thereof is formed into a horizontally elongated rectangle having an area which becomes larger than an area of the incident side, wherein only one of the left side and the right side of the light smoothing unit is made oblique relative to the incident side and the emitting side, and wherein said only one of the left side and the right side of the light smoothing unit is disposed obliquely at an angle of two degrees relative to a face line of the incident side.