Patent ID: 9664984
Date: 2017-05-30
CPC Classifications: G03B,H04N

Claim:
1. An optical unit having a reflective picture display device for displaying a picture by projecting light, the optical unit comprising: a light source generating the light; an illumination lens applying the light emitted from the light source to the picture display device; an opening determining an F-number of the illumination lens; and a projection optical device displaying a picture by projecting the light reflected by the picture display device, wherein the picture display device has a first state in which the applied light is reflected in an optical axis equivalent direction of an image to be displayed and a second state in which the applied light is reflected so as to have a component in a vertical equivalent direction of an image to be projected, a plane including an entire optical axis of the applied light reflected by the picture display device in the second state that differs from a plane formed by an optical axis of the light incident on the picture display device and an optical axis of the applied light reflected by the picture display device in the first state, and an opening size of the opening in a horizontal equivalent direction of the image to be projected is greater than in the vertical equivalent direction of the image to be projected, wherein, when an angle θonoff is formed by the optical axis of the light reflected by the picture display device in the first state and the optical axis of the light reflected by the picture display device in the second state and an F-number is determined by the opening, the condition cos θonoff<(2×F-number×F-number−1)/(2×F-number×F-number+1) is satisfied.