PHASE DELAY DEVICE AND OPTICAL PICKUP APPARATUS INCLUDING SAME

摘要

The present invention relates to a phase delay device and an optical pickup apparatus including same, and more specifically the objective of the present invention is to provide a phase delay device having first and second phase delay layers laminated, wherein the phase delay value ratio of the phase delay value of said first delay layer to the phase delay value of the second phase delay layer is optimized so that phase delay may be carried out by 1/4 of a wavelength of two respective laser rays with different wavelengths. To this end, the phase delay device of the present invention is a phase delay device that is arranged in the optical pathways of a laser ray for CD and a laser ray for DVD, thereby converting the polarization states of said laser rays, the phase device comprising first and second phase delay layers laminated, wherein the phase delay value of the second phase delay layer ranges from 140-190nm, and the phase delay value of said first phase delay layer ranges from 450-1300nm.