Magneto-optic overwrite disk recording system for erasing and overwriting in a single pass

Number of patents in Portfolio can not be more than 2000

United States of America Patent

PATENT NO 5390156
SERIAL NO

08130848

Stats

ATTORNEY / AGENT: (SPONSORED)

Importance

Loading Importance Indicators... loading....

Abstract

See full text

A magneto-optic overwrite disk recording system capable of canceling shifts of the front edge and the rear edge of the record mark due to accumulation of heat. The recording system includes a magneto-optic overwrite disk having a memory magnetic film and a record magnetic film, a first magnet for applying an initialization magnetic field with a first strength vertically to the disk, and a second magnet for applying a bias magnetic field with a second strength smaller than the first magnetic field to the disk in the direction opposite to the initialization magnetic field. The recording system further includes a laser diode for generating laser beams, an optical head for focusing the laser beam on the disk, a pulse generator for generating square wave pulses with a predetermined period, and a duty ratio controller for alternately increasing and decreasing the duty ratio of the square wave pulses every time data '1' of binary record data is generated. The laser diode is driven by a constant-current circuit for write power. There is connected a switch between the laser diode and the constant-current circuit for write power. The switch is turned on/off in accordance with the output pulse of the duty ratio controller so that the laser diode emits a pulsed beam.

Loading the Abstract Image... loading....

First Claim

See full text

Family

Loading Family data... loading....

Patent Owner(s)

  • FUJITSU LIMITED

International Classification(s)

  • [Classification Symbol]
  • [Patents Count]

Inventor(s)

Inventor Name Address # of filed Patents Total Citations
Izumi, Haruhiko Kawasaki, JP 44 463
Moritsugu, Masaharu Kawasaki, JP 19 226
Taguchi, Masakazu Kawasaki, JP 86 1039

Cited Art Landscape

Load Citation

Patent Citation Ranking

Forward Cite Landscape

Load Citation