Method and apparatus for detecting light from a multilayered object

摘要

An apparatus and method for reproducing signals from a multi-layer structured recording object wherein a linearly polarized laser beam illuminate the multi-layer structured object, such as a phase change recording medium via an objective lens system having an effective numerical aperture greater than 0.6. A light beam reflective from the object is passed to a filtering mask disposed to receive the reflected light beam. The filtering mask includes a first area that has a first transmissivity and a second area having a second transmissivity different than the first transmissivity. The reflected laser beam passed through the filtering mask is detected to reproduce signals from the recording medium.