| 摘要 |
An optical pick-up is provided to obtain a stable servo signal and to improve reproducing/recording performance by shielding a part of beam to prevent beam from entering an optical detecting unit using a beam shielding element. An optical pick-up(200) comprises a light source(210), an objective lens, a beam splitter(230), a diffraction element, a sensor lens, an optical detecting unit(290), and a beam shielding element. The light source emits beam of specified wavelength. The objective lens collects beam in an optical storage medium. The beam splitter permeates or reflects beam that is emitted from the light source or reflected from the optical storage medium. The diffraction element generates sub beam to generate a signal corresponding to the location of beam on the track. The sensor lens generates astigmatism for beam that is reflected from the optical storage medium. The optical detecting unit has a main detecting unit which receives main beam that passes through the diffraction element and two sub detecting units which receive sub beam that is generated by the diffraction element. The beam shielding element prevents beam that is reflected from another layer from entering the optical detecting unit by shielding a part of the beam.
|
