Patent ID: 7458713

Claim:
An illumination device comprising: a light guide plate having: an incident end face; an end face opposite the incident end face; an emergent surface extending from the incident end face to the end face; and a reflecting surface opposite the emergent surface and extending from the incident end face to the end face; and at least one light source provided at the incident end face of the light guide plate; the reflecting surface of the light guide plate including at least one of: concave portions arranged in rows juxtaposed to one another in a first direction parallel to the incident end face, each of the concave portions being elongated in a second direction that is perpendicular to the incident end face, concave portions in the same row being spaced apart from each other in the second direction, concave portions in adjacent rows being offset from each other in the second direction; and convex portions arranged in rows juxtaposed to one another in a first direction parallel to the incident end face, each of the convex portions being elongated in a second direction that is perpendicular to the incident end face, convex portions in the same row being spaced apart from each other in the second direction, convex portions in adjacent rows being offset from each other in the second direction.