Patent ID: 8488080

Claim:
An illumination system comprising: a light source that emits light; and a light guide that introduces the light through a light-incident end face facing the light source and that lets out the light from a light-exiting surface adjacent to the light-incident end face, wherein the light source is disposed adjacent to the light-incident end face and a position between a center line that divides the light-exiting surface of the light guide equally in the light-exiting direction of the light source and a line parallel to the center line, the line parallel to the center line being half way between the center line and an edge of the light guide; the light-incident end face of the light guide has at least one projection or recess in a direction intersecting the light-exiting direction of the light source; the projection or recess is inclined in one direction intersecting the light-exiting direction of the nearest of the light source and a second light source; the projection refracts the light in the direction of inclination intersecting the light-exiting direction, and the recess refracts the light in the direction opposite to the direction of inclination intersecting the light-exiting direction; and the projection or recess is configured to change a first optical axis of the light emitted from the light source and a second optical axis of the light emitted from the second light source, wherein changing the direction of the optical axes of the light emitted from the light source and the second light source prevents the light emitted from each of the light source and the second light source from overlapping at a central area in the light guide.