POLARIZED HOLOGRAM ELEMENT AND A PHOTO DETECTOR, AND AN OPTICAL PICKUP DEVICE COMPRISING THE HOLOGRAM ELEMENT AND THE PHOTO DETECTOR, SPECIFICALLY SO AS TO IMPROVE LIGHT EFFICIENCY AND SIMPLIFY A PICKUP CONTROL FUNCTION

摘要

PURPOSE: A polarized hologram element and a photo detector, and an optical pickup device comprising the hologram element and the photo detector are provided to form a polarized hologram for effectively separating light while reducing the number of optical splitting plates in order to receive a light passing through a polarized hologram element, thereby improving optical recording/reproducing performance. CONSTITUTION: An optical pickup device(30) comprises as follows. A light source(21) generates a light. An optical path separating element(23) separates an optical path of the light, and progresses the incident light of the light source(21) toward an optical disk(D) while progressing a reflected light of the disk(D) toward a photo detector(10). An objective lens(27) focuses the incident light on the disk(D). A polarized hologram element(17) separates the reflected light into different diffraction order lights. The photo detector(10) separately receives the incident light according to a diffraction order.