Lens alignment apparatus

A lens alignment apparatus comprising:

• a main lens holding frame having a main lens secured thereto;
• an adjusting lens holding frame to which an adjusting lens to be aligned with the main lens is secured;
• a plurality of radial grooves formed in one of adjacent end surfaces of the main lens holding frame and the adjusting lens holding frame, said radial grooves being arranged on a common circle whose center is located on an optical axis;
• a plurality of alignment holes corresponding to said radial grooves, formed in the other of said adjacent end surfaces of the main lens holding frame and the adjusting lens holding frame, said alignment holes including at least one alignment pin hole and at least one regular polygonal hole;
• at least one alignment pin including a cylindrical pillar portion which is relatively rotatably inserted in said alignment pin hole, and an eccentric cylindrical pillar portion which is relatively rotatably fitted in one of said radial grooves, said eccentric cylindrical pillar portion being eccentric with respect to said cylindrical pillar portion;
• and
• at least one alignment member including a centering pillar portion which can be inserted in said regular polygonal hole at different angular phases, and an aligning portion which can be engaged in another of said radial grooves regardless of the angular phase with respect to said regular polygonal hole, said aligning portion being provided with a plurality of pairs of parallel alignment surfaces having an identical width and different distances from the axis of the centering pillar portion.