Patent ID: 6938350

Claim:
An apparatus to project a reference plane comprising: a housing; and a projection unit within the housing, the projection unit including: five lasers each configured and arranged to emit a light beam; a collimator corresponding to each of the lasers to collided each light beam; an optical element corresponding to each of the lasers to convert each collimated light beam into an output line, the output lines being projected from the housing in different, substantially constant directions along the same plane to only form a single 360 degree reference plane; and a mounting device corresponding to each of the optical elements to mount the optical element to the projection unit, each mounting device operable to position the optical element to produce a substantially straight output line, each mounting device including; a plate onto which the optical element is mounted, the plate having at least one slotted opening for laterally displacing the optical element such that a corresponding collimated light beam is incident substantially on a center of the optical element.