| 摘要 |
PURPOSE: An optical pick-up is provided to increase the ratio of a main laser beam to a sub laser beam to improve optical efficiency. CONSTITUTION: An optical pick-up includes a laser diode(31) for generating a laser beam, a grating(33) for dividing the laser beam into three laser beams and controlling transmissivity of the divided laser beams, a collimator lens(35) for converting the three laser beams into parallel beams, and a prism(37) for controlling the direction of the parallel beams. The optical pick-up further includes a beam splitter(39) for passing the laser beams that have passed through the prism or refracting a laser beam reflected from an optical disk(45) vertically, a reflecting mirror for reflecting the laser beam toward the optical disk, an object lens(43) for refracting the reflected laser beam to form an optical spot, a flying spot lens(47) for irradiating the optical spot on a data track of the optical disk and focusing the reflected laser beam on photo-diodes, and a detector(%0) for detecting data from the reflected beam inputted from the flying spot lens. Liquid crystal is injected into the grating to control the transmissivity so as to adjust output power of the divided laser beams. |
