Patent ID: 8300175

Claim:
A lighting device, comprising: a light source; a light guiding plate having a light exit face, an opposed face opposite to the light exit face, a light entrance part that introduces light from the light source into the light guiding plate, and a plurality of reflecting parts formed on at least one of the light exit face and the opposed face for causing the introduced light to exit the light guiding plate from the light exit face; and a reflector disposed against the opposed face of the light guiding plate; wherein the plurality of reflecting parts are arranged on respective sets of arcs of concentric circles with each concentric circle having the light entrance part as its center, each of the plurality of reflecting parts having a long axis extending in a direction substantially orthogonal to a line connected between a center of the corresponding reflecting part and the center of the light entrance part; wherein for each of the sets of arcs of concentric circles, all of the reflecting parts are arranged at the same pitch; and wherein each of the plurality of reflecting parts arranged on one of the sets of arcs of concentric circles is positioned behind a space between two adjacent reflecting parts arranged on another of the sets of arcs of concentric circle adjacent to the one of the sets of concentric circles so as to partially overlap with each of the two adjacent reflecting parts.