Disc-shaped recording medium, manufacturing method thereof, and disc drive device
AssigneeSony Corporation
InventorsYoshiyuki Teraoka, Makoto Watanabe
Life of this patent
Estimating the term…
Abstract
A magneto-optical disk which reproduces information with an optical pickup head which uses an electromagnetic force as the driving force is provided. Other areas than at least the recording track are magnetized uniformly in a direction of canceling the influence of external magnetic field applied by the optical pickup head or a recording pattern having a frequency higher than modulation transfer function (MTF) of the optical pickup head is recorded to the other areas than at least the recording track. Read signals SP12 and SP14 from the magneto-optical disk are low in bit error rate.
Claims24
A disk-shaped recording medium to be played in a disk drive unit which reproduces information recorded in the disk-shaped recording medium by an optical pickup head including a drive means which uses an electromagnetic force as the driving force,
- the recording medium having recorded therein a signal which reduces the influence of an electromagnetic field applied by the optical pickup head, and
- the recording medium is a magneto-optical disk which is played by the domain wall displacement detection (DWDD) method.
A method of producing a disk-shaped recording medium to be played in a disk drive unit which reproduces information recorded in the disk-shaped recording medium by an optical pickup head including a drive means which uses an electromagnetic force as the driving force, the method comprising the step of:
- recording to the recording medium a signal which reduces the influence of an electromagnetic field applied by the optical pickup head, wherein
- the recording medium is a magneto-optical disk which is played by the domain wall displacement detection (DWDD) method.
A disk drive unit which reproduces information recorded in a disk-shaped recording medium by an optical pickup head including a drive means which uses an electromagnetic force as the driving force, the apparatus comprising:
- a recording means for recording to the disk-shaped recording medium a signal which reduces the influence of an electromagnetic field applied by the optical pickup head, wherein
- the signal recorded thereto is a recording pattern signal having a frequency higher than a modulation transfer function (MTF) of the optical pickup head.
A disk-shaped recording medium to be played in a disk drive unit which reproduces information recorded in the disk-shaped recording medium by an optical pickup head including a drive means which uses an electromagnetic force as the driving force,
- the recording medium having recorded therein a signal which reduces the influence of an electromagnetic field applied by the optical pickup head, wherein
- the signal recorded thereto is a recording pattern signal having a frequency higher than a modulation transfer function (MTF) of the optical pickup head.
A method of producing a disk-shaped recording medium to be played in a disk drive unit which reproduces information recorded in the disk-shaped recording medium by an optical pickup head including a drive means which uses an electromagnetic force as the driving force, the method comprising the step of:
- recording to the recording medium a signal which reduces the influence of an electromagnetic field applied by the optical pickup head, wherein
- the signal recorded thereto is a recording pattern signal having a frequency higher than a modulation transfer function (MTF) of the optical pickup head.
Dependencies are inferred from the claim text.