Patent ID: 7253853

Claim:
A lighting unit comprising: a light guide including a rear surface facing an object to be illuminated, a front surface opposite to the rear surface, a first side surface extending between the rear surface and the front surface, and a second side surface spaced from the first side surface; a lighting source adjacent to the light guide for supplying light to be directed from the first side surface toward the second side surface; and a reflector for reflecting light incident on the second side surface toward the first side surface; wherein the front surface of the light guide is formed with first slant portions and second slant portions, the first slant portions reflecting the light, traveling from the first side surface toward the second side surface, toward the rear surface of the light guide, the second slant portions reflecting the light, traveling from the second side surface toward the first side surface, toward the rear surface of the light guide, wherein the front surface of the light guide is also formed with flat portions and flat regions, said flat portions and said flat regions being parallel to the rear surface of the light guide and arranged to alternate with each other in a direction proceeding from the first side surface toward the second side surface of the light guide, each of said flat portions extending between paired first and second slant portions and cooperating with these slant portions to define a protrusion in the front surface of the light guide, each of said flat regions extending between paired first and second slant portions and cooperating with these slant portions to define a groove in the front surface of the light guide, said flat regions being closer to the rear surface of the light guide than said flat portions are, wherein the front surface of the light guide includes a preliminary flat region which is adjacent to the first side surface of the light guide and parallel to the rear surface of the light guide, the preliminary flat region being closer to the first side surface than any one of the first and the second slant portions, the preliminary flat region being closer to the rear surface of the light guide than any one of said flat portions in the front surface of the light guide, wherein the first side surface of the light guide is parabolic and convex away from the second side surface, light emitted from the light source being reflected by the first side surface toward the second side surface.