Patent ID: 8681831

Claim:
A light scanning unit, comprising: a substrate; a plurality of vertical cavity surface emitting lasers (VCSELs) which are respectively provided at a plurality of positions on a surface of the substrate, each VCSEL comprising a light emitting surface which emits a light, each of said light emitting surfaces having a first, peripheral portion and a second, interior portion; an isolator which is provided to electrically and optically isolate each VCSEL on the substrate and to directly contact the substrate; a monitoring detector provided on only the isolator and the first, peripheral portion of each light emitting surface to receive directly only a part of the light emitted from each VCSEL so as to monitor an amount of the light emitted from each VCSEL, wherein a remainder of the light passes through the second, interior portion of each light emitting surface; and a beam deflecting unit which deflects the remainder of the light emitted from each of the respective VCSELs in a main scanning direction of a photosensitive medium, wherein the light emitting surface emits the light beam in a vertical direction to the substrate, and wherein the entire light emitting surface having the first, peripheral portion and the second, interior portion is flat and parallel to the substrate.