Patent ID: 6877872
Filing Date: 2005-04-12
Classification: G02B

Abstract:
1. A spread illuminating apparatus comprising: a light conductive plate shaped substantially rectangular and made of a light-transmissible material; a spot-like light source disposed close to or in contact with a light entrance surface formed at a corner of said light conductive plate; a light reflection pattern formed on a major surface of said light conductive plate and including a plurality of grooves which each extend so as to shape a substantially minor arc with respect to said spot-like light source and which are arrayed concentrically wherein each of said grooves has its depth gradually increasing with increase in a distance from a diagonal line formed on said major surface of said light conductive plate; and a plurality of lenticular elements made of a light-transmissible material, provided on a major surface of said light conductive plate opposite to said major surface provided with said light reflection pattern, and having their respective longitudinal directions oriented perpendicular to said plurality of grooves of said light reflection pattern.