JPH02130701A - Magneto-optical recording device - Google Patents

Abstract

PURPOSE:To highly accurately record information on an optical disk with low power by providing plural modulation coils and respectively connecting current supply circuits to the modulation coils. CONSTITUTION:The 1st and 2nd current supply circuits 8A and 8B of this magneto-optical recording device respectively supply electric currents corresponding to signals to be recorded on a magneto-optical disk 1 to modulation coils 7A and 7B when the signals are generated by means of a recording signal generation circuit 9 and inputted to the circuits 8A and 8B. Therefore, the coils 7A and 7B are conducted and excited by means of an exciting element 6 in corresponding to the signals to be recorded and modulating magnetic fields produced by the coil 7A and 7B are applied to the optical disk 1. Therefore, when a laser light beam 5 is projected on one surface side of the disk 1 while the modulating magnetic field is applied to the other surface side, information to be recorded can be recorded on the magneto-optical disk 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a magneto-optical recording device that records information by applying light and a magnetic field to a magneto-optical disk.

[Conventional technology]

A magneto-optical recording device projects a laser beam onto one side of a magneto-optical disk on which information is to be recorded, and emits a magnetic field related to the signal to be recorded on the other side of the magneto-optical disk at the position where the laser beam is projected. and is configured to record information on the magneto-optical disk.

FIG. 2 is a schematic partial cross-sectional perspective view showing the main parts of this type of magneto-optical recording device. An optical head 4 that emits a laser beam is located on one surface side of the magneto-optical disk 1, and the laser beam 5 is transmitted through the substrate 2 of the magneto-optical disk 1 to form a recording film 3.
It is projected so that it is in focus. On the other side of the magneto-optical disk 1, an excitation element 6 having a single modulation coil 7 for inputting a signal of information to be recorded is located.

This excitation element 6 is formed, for example, in the shape of a rectangular parallelepiped,
The negative side shaft end surface 6a faces the magneto-optical disk 1. By energizing the modulation coil 7, the excitation element 6 can apply a perpendicular magnetic field to the information recording position of the magneto-optical disk 1 in a direction corresponding to the information to be recorded. That is, the information recording position of the magneto-optical disk 1 heated at the focused position of the laser beam moves away from the irradiation position of the laser beam due to the rotation of the magneto-optical disk 1, and the temperature decreases.
When the temperature drops to the Curie point of the recording film 3, the magnetic field applied from the excitation element 6 serves as a position where the magnetization direction of the recording film 3 can be fixed in the direction of the magnetic field. is positioned. On the other hand, a recording signal from a recording information generation circuit 9 that generates a signal of information to be recorded is inputted to a current supply circuit 86.
The output B is connected to the modulation coil 7.

In this magneto-optical recording device, when a signal to be recorded on a magneto-optical disk is generated by a recording signal generation circuit 9 and the signal is input to a current supply circuit 8, the current supply circuit 8 generates a current corresponding to the input signal. is supplied to the modulation coil 7. Thereby, the excitation element 6 applies a modulated magnetic field to the magneto-optical disk 1 in accordance with the signal to be recorded. Information to be recorded is recorded on the magneto-optical disk 1 by projecting the laser beam 5 onto one side of the magneto-optical disk 1 and applying the above-described modulated magnetic field to the other side.

[Problem to be solved by the invention]

The conventional magneto-optical recording device described above includes a single modulation coil 7 in the excitation element 6. The inductance of this modulation coil 7 is usually several μH, and a high frequency current of several MHz or more is passed through this modulation coil 7. Therefore, the excitation power of the modulation coil 7 is large, and the rise of the excitation current that is passed through it is large. The problem is that it takes a long time.

In view of such problems, it is an object of the present invention to provide a magneto-optical recording device in which the excitation power of the excitation element can be reduced and the rise time of the excitation current of the modulation coil is short.

[Means to solve the problem]

In the magneto-optical recording device according to the present invention, the excitation element is provided with a plurality of modulation coils, and each of the modulation coils is connected to a separate current supply circuit.

[Effect]

A recording signal is commonly input to the plurality of current supply circuits. Each current supply circuit separately supplies current to its corresponding modulation coil. Each modulation coil generates a modulation magnetic field corresponding to a recording signal. A modulated magnetic field that is the sum of each modulated magnetic field is applied to the magneto-optical disk.

As a result, if the strength of the magnetic field generated by a single modulation coil is generated by multiple modulation coils whose total number of turns is equal to the number of turns of the single modulation coil, the current in each modulation coil will decrease. Therefore, the excitation power of the excitation element decreases.

〔Example〕

The present invention will be described in detail below with reference to drawings showing embodiments thereof. FIG. 1 is a schematic partial cross-sectional perspective view showing the main parts of a magneto-optical recording device according to the present invention. An optical head 4 that emits a laser beam is located on one side of the magneto-optical disk 1, and the laser beam 5 is transmitted through the substrate 2 of the magneto-optical disk 1 and projected onto the recording film 3 so as to obtain a focused point. has been done. On the other side of the magneto-optical disk 1, there is a first disk for inputting a signal of information to be recorded.
゜An excitation element 6 made of magnetic material is located which is provided with two second modulation coils 7A and 7B, respectively. These modulation coils 7A and 7B have, for example, the same winding direction and the same number of turns, and are each selected to have the same number of turns as the number of turns when one modulation coil is used.

This excitation element 6 is formed, for example, in the shape of a rectangular parallelepiped,
The negative side shaft end surface 6a faces the magneto-optical disk 1. By energizing the modulation coil 7, the excitation element 6 can apply a perpendicular magnetic field to the information recording position of the magneto-optical disk 1 in a direction corresponding to the information to be recorded. That is, the information recording position of the magneto-optical disk 1 heated at the focal point position of the laser beam moves away from the irradiation position of the laser beam due to the rotation of the magneto-optical disk l, and the temperature decreases, and the temperature reaches the Curie point of the recording film 3. When it descended to
The excitation element 6 is a position where the magnetization direction of the recording film 3 can be fixed in the direction of the magnetic field by the magnetic field applied from the excitation element 6.
This is for positioning the shaft end surface 6a on one side. On the other hand, the recording signal of the recording information generation circuit 9 that generates the signal of information to be recorded is transmitted to the first current supply circuit 8A and the second current supply circuit 8.
B, and each output side of the current supply circuits 8A and 8B is connected to the first.B. It is connected to second modulation coils 7A and 7B.

In the magneto-optical recording device of the present invention configured as described above, the recording signal generating circuit 9 generates a signal to be recorded on the magneto-optical disk 1, and the signal is transmitted to the first . second current supply circuit 8A,
8B, each current supply circuit 8A, 8B modulates the current corresponding to the input signal to the modulating coil 7A, 7B.
supply to Thereby, the modulation coils 7A, 7B are energized, the excitation element 6 is excited in accordance with the signal to be recorded, and the modulated magnetic field generated by each modulation coil 7A, 7B is applied to the magneto-optical disk 1. Therefore, information to be recorded is recorded on the magneto-optical disk 1 by projecting the laser beam 5 onto one surface of the magneto-optical disk 1 and applying the above-described modulated magnetic field to the other surface.

Incidentally, the modulating magnetic field H generated by each modulating coil 7Δ, 7B is proportional to the current of each modulating coil.

Also, the rise of the current in the modulation coil elf/eat is θ t L However, ■ is the current of the modulation coil t is time ■ is the output voltage of the current supply circuit is the inductance of the modulation coil It is expressed as

Therefore, in order to obtain the strength of the magnetic field generated by a single modulation coil with the modulation coils 7A and 7B, the respective current of each modulation coil 7A and 7B should be twice the current of the single modulation coil. This shortens the rise time of the current.

Furthermore, since each excitation power of the modulation coil 74.7B is the product of the inductance of the modulation coil and the square of the current flowing through it, if the current of each modulation coil is, for example, A, the excitation power of each modulation coil is is χ, and the excitation power of the two modulation coils 7A and 7B is 2, which is A times the number of modulation coils. Therefore, when using multiple modulation coils, the excitation power required to obtain the same magnetic field strength as when using a single modulation coil can be reduced by the number of modulation coils, allowing information to be recorded with low power. obtain.

Furthermore, high-density recording is possible and the transfer rate can be increased.

Although two modulation coils are used in this embodiment, it is possible to use a larger number of modulation coils, and it goes without saying that as the number of modulation coils increases, the excitation power can be further reduced. .

Further, in this embodiment, the optical head 4 and the excitation element 6 are located separately on different sides of the magneto-optical disk 1, but the structure is such that the optical head 4 and the excitation element 6 are located on one side. However, the same effect as described above can be obtained.

Furthermore, although the excitation element 6 is formed into a rectangular parallelepiped shape (■-shape), it may be substantially C-shaped, U-shaped, E-shaped, etc., but is not limited to this. Furthermore, the same effect can be achieved even if the number of turns of the modulation coils 7A and 7B is not made the same, but the current of each modulation coil is made different, and the excitation element 6 is wound with a modulation coil having a different number of turns in relation to each current. Needless to say, this effect can be obtained. Further, although this embodiment uses a magneto-optical recording device, similar effects can be obtained even if a magneto-optical recording/reproducing device is used.

〔Effect of the invention〕

As detailed above, according to the magneto-optical recording device of the present invention,
Information to be recorded can be recorded on a magneto-optical disk with low power and with high precision. Further, it has excellent effects such as enabling high-density recording and increasing the transfer rate.

[Brief explanation of drawings]

FIG. 1 is a schematic partial cross-sectional perspective view showing the main parts of a magneto-optical recording apparatus according to the present invention, and FIG. 2 is a schematic partial cross-sectional perspective view showing the main parts of a conventional magneto-optical recording apparatus. 1... Magneto-optical disk 3... Recording film 4... Optical head 6... Excitation element 7^, 7B... Modulation coils 8A, 8B... Current supply circuit 9... Recording signal generation Circuit Note that in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1. In a magneto-optical recording device provided with an excitation element having a modulation coil in order to apply an external magnetic field to a magneto-optical disk, a plurality of the modulation coils are provided, and each modulation coil 1. A magneto-optical recording device characterized in that a separate current supply circuit is connected to each.