Morrison & Foerster LLP
Method and apparatus for reproducing an optical signal
An apparatus for reproducing information stored in an optical recording medium which comprises marks or pits which are arranged at a pitch less than λ/2NA, wherein λ is a wavelength of light used for reproduction and NA is an numerical aperture of an objective lens. The apparatus generally comprises a laser diode, a polarization beam splitter, an objective lens, beam splitters, a low-frequency light detecting system with a photodetector, a high-frequency light detecting system with a photodetector, and a signal processing circuit for combining detection signals from the photodetectors. In the high-frequency light detecting system, before a convergent lens, a shielding band is provided so as to shield the middle of a bundle of rays of reproduction light.
Minolta Co., Ltd. National Institute of Advanced Industrial Science and Technology TDK Corporation
G G G
G11B G11B G11B
inventional inventional inventional
Takashi Akira Nobufumi Takashi Manami Junji
Kikukawa Sato Atoda Nakano Kuiseko Tominaga