Patent ID: 7530719

Claim:
A light source device comprising: a light conductor which has a first light incident end surface and a second light incident end surface that extend in substantially parallel directions relative to each other and that are positioned on mutually opposite sides, and a light emitting surface; a first primary light source and a second primary light source which are disposed respectively adjacent to said first light incident end surface and said second light incident end surface; and a light deflecting element which has a light incident surface disposed facing said light emitting surface and a light emitting surface positioned on the side opposite from this light incident surface, wherein a directional light emitting functional part with an average inclination angle of 0.5 to 15° is formed on at least one surface of said light conductor, i.e., the light emitting surface or the back surface positioned on the side opposite from this light emitting surface, a plurality of mutually parallel prism rows that extend in a direction substantially parallel to said first light incident end surface and said second light incident end surface are formed on the light incident surface of said light deflecting element, each of these prism rows has a first prism surface on the side close to said first primary light source and a second prism surface on the side close to said second primary light source, said first prism surface has a first region that extends in the direction of extension of said prism rows and a second region that extends in the direction of extension of said prism rows, the vertical angle of the prism rows is 80 to 120°, the difference in the angle of inclination between said first region and said second region is 5 to 20°, and said second region has a smaller angle of inclination with respect to the normal direction of the prism row formation plane than said first region.