Lens holder having an adjustment groove of a taper shape

摘要

Disposed in a corner portion formed by a base plate (122) and a vertical wall (124) with being always pressed against the corner portion by a presser bar spring (16), a lens holder (14A) has an adjustment groove (14Aa) extending in a direction perpendicular to the vertical wall. The adjustment groove (14Aa) has a taper shape where a width thereof becomes narrower in proportion to near to the vertical wall and the width thereof becomes wider in proportion to apart from the vertical wall. By moving an adjustment pin (18a) with the adjustment pin inserted in the adjustment groove (14Aa) through a hole (122b) formed in the base plate, the lens holder is moved along an optical axis (OA) of a laser beam, thereby adjusting a position of a beam spread lens (BSL) without a center axis (CA) thereof out of the optical axis.