Optical information recording/reproducing apparatus including a beam axis adjusting device for adjusting a position of a beam incident to a diffraction grating

摘要

In an optical information recording and/or reproducing apparatus, a light beam from an irradiation optical system is split into a plurality of beams by a diffraction grating. The plurality of light beams split by the diffraction grating are caused to irradiate an optical information recording medium. A light beam from the optical information recording medium is detected by a detection optical system. A beam axis adjusting mechanism is provided in an optical path between the irradiation optical system and the diffraction grating so as to adjust a position of a beam incident to the diffraction grating.