| 摘要 |
PURPOSE: An optical pickup having plural LEDs(Light Emitting Diodes) is provided to change an arranged location and a diffraction pattern of an SWPF(Short Wave Pass Filter), included in the optical pickup reproducing by read or recording digital data respectively recorded in a CD(Compact Disc) and DVD(Digital Versatile Disc) having mutually different formats, so as to prevent light losses. CONSTITUTION: A first light source(21) emits light having a wavelength appropriate for a DVD. A second light source(31) emits light having a wavelength appropriate for a CD. A polarized beam splitter(20) selectively transmits or reflects at an angle of 90 degrees light respectively emitted from the first and second light sources. A collimator lens(11) converts the transmitted or reflected light into parallel light. A reflective mirror(12) reflects the parallel light at an angle of 90 degrees in a disk direction. An objective lens(15) having 0.6 aperture number connects the reflected light with a recording surface of the CD or DVD for focusing. And an SWPF(130) secures an aperture number appropriate for the CD, between the second light source and the polarized beam splitter(20). |
