OPTICAL HEAD, AN LD MODULE, AN OPTICAL RECORDING/REPRODUCING DEVICE AND A DIFFRACTION ELEMENT USED FOR THE OPTICAL RECORDING/REPRODUCING DEVICE, SPECIFICALLY IN REFERENCE TO EASILY CONDUCTING A TRACKING CONTROL OR A FOCUS CONTROL WITH A SIMPLE CONFIGURATION

摘要

PURPOSE: An optical head, an LD module, an optical recording/reproducing device and a diffraction element used for the optical recording/reproducing device are provided to have certain grating patterns or to use a diffraction element, thereby removing DC offset components while dividing a beam regardless of whether a lens shift exists. CONSTITUTION: A light source(1) consists of a laser unit. A diffraction element(2) divides a laser beam emitted from the light source(1) into plural beams. A collimator lens(3) emits the divided beams toward a beam splitter(4). The beam splitter(4) transmits the beams, and reflects a reflected light of an optical disk(5) toward a detector(6). An objective lens(7) condenses the beams. An anamorphic lens(8) focuses the reflected light on the detector(6). The detector(6) receives the reflected light.