Frishauf, Holtz, Goodman & Woodward
Optical memory device
 An optical memory device comprises a modulator for modulating a laser beam in accordance with recording data, an objective lens for focusing the output laser beam from the modulator on a recording medium, a photosensor arranged at the conjugate position with the focal point of the objective lens, and a judging circuit for detecting erroneous writing in accordance with an output from the photosensor and a source of the recording data. The photosensor is divided into first and second segments by a line which is perpendicular to a direction corresponding to relative movement of the focused light beam on the recording medium. The difference signal between the outputs from the first and second segments is supplied to the judging circuit. 
Olympus Optical Co., Ltd.
G G
G11B G11B
inventional inventional
Kiichi
Kato