| 摘要 |
PURPOSE: To detect tracking error easily by employing a three beam tracking system optical pickup having a light source generating a laser beam split into three. CONSTITUTION: A laser light source 30 radiates a main beam through a first laser light emitting element 301 for reading out a data from a data recording medium D, a first guide beam through a second movable laser light emitting element 302, and a second guide beam through a second movable laser light emitting element 303. In order to radiate a laser beam from the laser light source 30 and read out information recorded on the data recording medium D, lens groups 36, 38 determine a path for beam incident on the data recording medium D and a path for beam being reflected therefrom. The pickup further comprises a lens group including objective lenses 36, 38 for focusing a beam incident on the surface of data recording medium D, and means for receiving a part of beam reflected on the data recording medium D in order to detect tracking error. |
