Optical recording/reproducing apparatus

摘要

An optical recording apparatus which reduces light loss by expanding the laser beam diameters irradiated from a plurality of beam sources, and reducing the expanded beam diameters immediately before focusing the beams onto an information recording medium to make the beams circular, thereby minimizing deviation of the laser beam from the optical axis. An optical system for use in recording apparatus with a multi-beam optical head provided with a plurality of laser beam sources in a fixed unit which reduces light loss by minimizing deviation of the laser beam from the optical axis, and also by maintaining the laser power of each laser beam at a predetermined intensity independent of changes in distance between the fixed unit half and the moving unit half of the optical system by detecting intensities of the laser beams focused on a recording medium.