| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup which can obtain a desirable signal by shaping a beam composed of a plurality of wavelengths, correcting tilt to the light axis, and correcting displacement with a simple and compact configuration. <P>SOLUTION: The optical pickup 10 of three wavelengths to one lens has a beam shaping mirror 7 which transform light intensity distribution of the laser beams B1 to B3 of respective wavelengths from elliptic shape to circular shape by emitting respective laser beams B1 to B3 from a transparent plane 7a to a light path between an objective lens 8 and a laser source 1a, 1b, reflect the beam on a reflection plane 7b not parallel to the transparent plane 7a, and emit it from the transparent plane 7a. The beam shaping mirror 7 is constructed by a liquid crystal 7c which forms the transparent plane 7a and the reflection plane 7b in a fully filled condition with a trapezoidal cross section, and a liquid crystal display driving source 11 is prepared to electrically drive the liquid crystal 7c for keeping a constant reflactive index of the liquid crystal 7c regardless of the wavelength of the laser beam B1 to B3 emitted to the beam shaping mirror 7. <P>COPYRIGHT: (C)2008,JPO&INPIT |
