OPTICAL TYPE DATA RECORDER

摘要

An optical data recording device for focusing a laser beam (52) on a recording medium (60) for storing and reading out information therefrom. The device is characterized by using a high efficiency holographic grating (30) as a polarization beam splitter. In a forward collimated light path the holographic grating diffracts a light beam from a laser (54) on an objective lens. The beam is reflected from the surface towards the recording medium (60) and transmitted through the grating onto a light detector (64). The grating (30) further provides for correcting a typical elliptical light beam shape from the laser (54) to a circular beam shape as well as for correcting the astigmatism typically found in the wave fronts emitting from a laser diode.