Optical pick-up apparatus and optical disc unit therefor

摘要

Provided are a thin optical pick-up apparatus which can record and reproduce data to and from both high recording density disc and low recording density disc, and a thin optical disc unit using this optical pick-up apparatus. The optical pick-up apparatus comprises a short wave LDA 11, a long wave LDAB 12, a beam splitter 41, a riser prism 23 for turning an optical axis into an optical axis perpendicular to the optical disc, a composite filter 33 being integrally incorporated with the objective lens 32 while a surface of the composite filter 33 is opposed to an oblique surface of the riser prism 23 in parallel with each other.