OPTICAL PICKUP DEVICE OF WAVEGUIDE TYPE CONVERGING SECONDARY BEAMS

摘要

PURPOSE: An optical pickup device of wave guide type converging secondary beams is provided to improve playback efficiency and to easily detect an error signal by increasing the amount of beam returned to an optical detector. CONSTITUTION: Laser beam is outputted from a laser diode(10) for being reflected on the lower surface of a waveguide optical element(20). The laser beam is irradiated to a duplex lens(30). The laser beam is collected on an optical disk(D) by a main beam object lens(32) for being diffracted. A certain part of the laser beam passing through the main object lens is transferred to a waveguide(22) by a grate surface(24). The laser beam is collected in first and second error optical detectors(48,50) to detect focus error signals. The laser beams passing through first and second auxiliary beam object lenses(34,36) are collected on first and second auxiliary beam detectors(44,46) for outputting RF signal.