Pioneer Electronic Corporation

Sakashi Otaki

Hideki Hatano

Norikiyo Tajiri

Shigeru Kato

Mikio Kanai

Sigeru Kato

Disclosed is an optical recording medium having a vertical magnetization film on which information is recorded along with an optically readable sign indicating whether or not erasing of recorded information is permitted. Also disclosed is a system for recording information on the recording medium, whereby the erasing of the information recorded on the recording medium is inhibited or permitted in accordance with a sensed sign on the recording medium.

Magneto-optical recording medium and method for preventing the erasing

Disclosed is a system for recording and playing back information utilizing a magneto-optical disc memory having a vertical magnetization film on and from which the information is recorded and read out by an optical means. In order to simplify the construction of the system, an optical system including an objective lens and a tracking mirror is used both as a part of an optical path of a recording light beam and a part of an optical path of a readout light beam. The wavelengths of the recording light beam and the readout light beam are selected to be different so that the light beams are easily discriminated in the optical system.

System for recording and playing back information with magneto-optical

Disclosed is a method and system for recording and playing back information utilizing a recording medium having a vertical magnetization film on and from which the information is recorded and read out by an optical means, characterized by changing the direction of the magnetic field applied on the recording medium during the application of a recording light beam so as to maintain the recording track of portions of the recording medium on which the previously recorded information is erased by the application of the recording light beam during editing operations.

Method and system for optically recording and playing back information

Disclosed is an information recording system having a recording light beam passing through a focus lens, and a focus servo mechanism for adjusting the position of the focus lens, characterized by the provision of a bias beam of a weak intensity for producing a continuous control signal for the focus servo mechanism.

Growing community of inventors

Tokorozawa, Japan

Sakashi Otaki