Optical apparatus having a luminous flux shaping filter

摘要

An optical apparatus including a luminous flux shaping filter for converting a shape of an incident beam without bending an optical path of the incident beam. A light beam emitted from a focusing laser source comprising a semiconductor laser is converted into a parallel light beam by a collimator lens, and then enters the luminous flux shaping filter. The luminous flux shaping filter is positioned on an optical path in the apparatus in the manner that a major axis of an oval light beam from the collimator lens is perpendicular to a longitudinal area in which the transmittance is the highest in the filter. As a result, the luminous flux shaping filter converts the oval light beam into a substantially circular light beam without bending an optical path of the light beam.