| 摘要 |
PURPOSE:To reduce the number of parts of an optical pickup by using a photo diode consisting of an amorphous thin film essentially consisting of Si. CONSTITUTION:A photo diode 16 which consists of an amorphous thin film essentially consisting of Si and has the pin structure is formed on one face of quartz 17, and a micro Fresnel lens 15 is formed on the other face. The light from a semiconductor laser 10 passes a half prism 11 and a collimator lens 12 and is condensed on a recording medium 14 by an objective lens 13, and the reflected light including information on the medium 14 turns the optical path by the prism 11 and passes the lens 15 and is made incident on the diode 16. The lens 15 and the diode 16 are integrated on quartz 17 to not only reduce the number of parts but also facilitate positioning, and the light whose wavelength is <=700nm is used to obtain a sufficient output. |
