External magnetic field generation apparatus capable of light intensity modulation and magnetic field modulation
First Claim
1. An external magnetic field generation apparatus for use in a recording and reproduction apparatus which records information on a magneto-optical recording medium based on a magnetic field modulation system and a light modulation system, and said apparatus applying a magnetic field to a portion of the magneto-optical recording medium where the light beam is projected, comprising:
- first magnetic field generation means for generating an a.c. magnetic field which is reversed at a high speed, said first magnetic field generation means being used for the magnetic field modulation system;
second magnetic field generation means for generating a strong d.c. magnetic field such that power consumption coincides with that of said first magnetic field generation means, said second magnetic field generation means being integral with said first magnetic field generation means, said second magnetic field generation means being used for the light modulation system; and
power supply means for selecting one of said first magnetic field generation means and said second magnetic field generation means responsive to a switching signal, and for supplying power to said selected magnetic field generation means.
1 Assignment
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Accused Products
Abstract
An external magnetic field generation apparatus is used for a recording and reproduction apparatus which records information on a magneto-optical recording medium based on the magnetic field modulation system and the light modulation system, and applies a magnetic field to the portion of the magneto-optical recording medium where the light beam is projected. The apparatus has the first electro-magnet, used for the magnetic field modulation system, for generating an a.c. magnetic field which is reversed at a high speed. The apparatus has the second electro-magnet, used for the light modulation system, for generating a strong d.c. magnetic field such that power consumption coincides with that of the first electro-magnet.
The second electro-magnet is integral with the first electro-magnet. The apparatus has a driver for selecting one of the electro-magnets in response to a switching signal, and the driver supplies power to the selected electro-magnet.
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Citations
14 Claims
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1. An external magnetic field generation apparatus for use in a recording and reproduction apparatus which records information on a magneto-optical recording medium based on a magnetic field modulation system and a light modulation system, and said apparatus applying a magnetic field to a portion of the magneto-optical recording medium where the light beam is projected, comprising:
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first magnetic field generation means for generating an a.c. magnetic field which is reversed at a high speed, said first magnetic field generation means being used for the magnetic field modulation system; second magnetic field generation means for generating a strong d.c. magnetic field such that power consumption coincides with that of said first magnetic field generation means, said second magnetic field generation means being integral with said first magnetic field generation means, said second magnetic field generation means being used for the light modulation system; and power supply means for selecting one of said first magnetic field generation means and said second magnetic field generation means responsive to a switching signal, and for supplying power to said selected magnetic field generation means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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- 10. An external magnetic field generation apparatus for use in a recording and reproduction apparatus which records information on a magneto-optical recording medium, the apparatus comprising a first winding wire and a second winding wire wound about differing ends of a common magnetic core to form a first magnetic field generation means and a second magnetic field generation means, respective lengths and diameters of the first winding wire and the second winding wire being chosen so that the first winding wire and the second winding wire have the same electrical resistance.
Specification