Apparatus for recording a wobbling, spiral guide groove on an optical disc
First Claim
1. Apparatus for forming a wobbling, substantially spiral pregroove on a disc-shaped recording medium for use as a tracking guide when subsequently recording data on the recording medium, said apparatus comprising:
- means for rotating said disc-shaped recording medium;
a laser beam source for generating a laser beam;
means for moving said laser light beam source radially relative to said disc-shaped recording medium;
optical means for guiding said laser beam to said disc-shaped recording medium, said optical means including deflecting means for deflecting said laser beam in a radial direction of said disc-shaped recording medium in response to a modulated control signal while said disc-shaped recording medium rotates and said laser light beam source moves radially relative to said recording medium, whereby a wobbling, substantially spiral tracking guide pregroove is formed on said disc-shaped recording medium; and
control signal generating means connected to receive a first signal that has a first predetermined frequency and to receive a coded information second signal that has a second predetermined frequency at least an order of magnitude lower than said first predetermined frequency, said modulated control signal being generated by superimposing said second signal on said first signal, said modulated control signal being fed to said deflecting means for causing said laser light beam to wobble as the substantially spiral pregroove is formed on said recording medium in accordance with said modulated control signal.
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Accused Products
Abstract
Recording apparatus for forming a track on a disk-shaped recording medium capable of optical information reproduction, comprises a deflection device for deviating a recording beam from a light source in a radial direction of the disk-shape recording medium and a deflection-control signal generating device. The deflection control signal is developed from the superimposition of a first signal having a predetermined frequency and a second signal having a lower frequency than the predetermined frequency. The superimposition of the second signal can be done while retaining the predetermined frequency.
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Citations
6 Claims
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1. Apparatus for forming a wobbling, substantially spiral pregroove on a disc-shaped recording medium for use as a tracking guide when subsequently recording data on the recording medium, said apparatus comprising:
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means for rotating said disc-shaped recording medium; a laser beam source for generating a laser beam; means for moving said laser light beam source radially relative to said disc-shaped recording medium; optical means for guiding said laser beam to said disc-shaped recording medium, said optical means including deflecting means for deflecting said laser beam in a radial direction of said disc-shaped recording medium in response to a modulated control signal while said disc-shaped recording medium rotates and said laser light beam source moves radially relative to said recording medium, whereby a wobbling, substantially spiral tracking guide pregroove is formed on said disc-shaped recording medium; and control signal generating means connected to receive a first signal that has a first predetermined frequency and to receive a coded information second signal that has a second predetermined frequency at least an order of magnitude lower than said first predetermined frequency, said modulated control signal being generated by superimposing said second signal on said first signal, said modulated control signal being fed to said deflecting means for causing said laser light beam to wobble as the substantially spiral pregroove is formed on said recording medium in accordance with said modulated control signal. - View Dependent Claims (2, 3)
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4. A method of forming a wobbling, substantially spiral pregroove on a disc-shaped recording medium for use as a guide when subsequently recording data on the recording medium, said method comprising the steps of:
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rotating said disc-shaped recording medium; radiating a laser beam; guiding the laser beam to said disc-shaped recording medium and moving the laser beam radially on the rotating recording medium to form a substantially spiral pregroove, said guiding step including a step of deflecting the laser beam in a radial direction of said disc-shaped recording medium in response to a modulated control signal while said disc-shaped recording medium rotates and said laser light beam is moved radially on the rotating recording medium, whereby a wobbling, substantially spiral pregroove is formed on said disc-shaped recording medium; generating said modulated signal by switching on and off a first signal that has a first predetermined frequency in accordance with a second signal that contains coded information and has a second predetermined frequency at least an order of magnitude lower than said first predetermined frequency; and controlling said deflecting of said laser beam in accordance with said modulated control signal for wobbling said laser beam while forming said spiral pregroove on said recording medium. - View Dependent Claims (5)
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6. A disc-shaped recording medium capable of having a data signal optically recorded thereon and optically reproduced therefrom, said recording medium comprising:
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a substrate layer having first and second surfaces, said first surface having formed thereon a substantially spiral pregroove which is wobbled in a radial direction of said disc-shaped recording medium and formed by a control signal consisting of a first signal that has a predetermined frequency and that has been modulated by a second signal that contains coded information and that has a frequency at least an order of magnitude lower than said predetermined frequency; a recording layer formed on the first surface of said substrate layer and adapted for subsequent optically recording the data signal thereon; and a protective layer formed on said recording layer.
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Specification