JPH03263639A - Magneto-optical recording device - Google Patents

Abstract

PURPOSE:To obtain a magneto-optical recording device, which can use both of a magneto-optical recording medium for optical modulation recording and a magneto-optical recording medium for magnetic field modulation recording where direct overwriting can be executed, without making the scale of the device large by making the constitution of the device that a magnetic field is impressed on the magneto-optical recording medium through a floating slider. CONSTITUTION:A magnetic head H which modulates a magnetic field is pro vided on the floating slider 5 and a bias magnet 7 which generates the steady magnetic field is fixedly arranged to the upper part of the slider 5. At an action time, the slider 5 is lifted to the extent of 0.1-0.9mm and held. Besides, the magnetic field generated by the magnet 7 is impressed on the magneto-optical recording medium through the slider 5. In such a case, since a large moving mechanism is not used for the head H, an error between the position of the head H by the elevating and lowering action of the slider 5 and the position of a laser spot by an optical head 1 is kept to be <=0.05mm. Thus, both of the medium for optical modulation system recording and the medium for mag netic field system recording where the direct overwriting can be executed can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magneto-optical recording device capable of both magnetic field modulation recording and optical modulation recording.

[Prior Art] Conventionally, a magneto-optical recording device modulates the intensity of a light beam with an information signal and irradiates it onto a magneto-optical disk, which is a magneto-optical recording medium, while applying an external magnetic field to the irradiated portion to generate an information signal. A recording method, so-called optical modulation recording, is known and has been put into practical use. The recording principle of this method will be explained with reference to FIG. It is assumed that in the initial state before recording, the magnetization of the magnetic film 100b in the magneto-optical disk 100 is uniformly directed downward. Here, the on/off of the laser light source 101 that generates the light beam is controlled by the information signal. 102 is a turn-off circuit that turns on the laser light source. The laser beam is focused onto the magnetic film 100b by the optical system 103. When a laser beam is irradiated, the temperature of the area (spot) irradiated with the laser beam increases, and when the temperature reaches the Curie temperature or higher, magnetization reversal becomes easy. On the other hand, the bias magnet 104 is connected to the constant current source 10
A constant DC current is supplied from 5 to generate an upward steady magnetic field B against the disk surface. Therefore, the magnetization of only the portion of the magnetic film 100b that is irradiated with the laser beam is reversed so that it points upward, and as the magnet passes through the portion of the laser beam that is irradiated and the temperature decreases, the magnetization is preserved. By turning on and off the laser beam, an information signal is recorded in the magnetic film 100b by a pattern of magnetized regions approximately the same size as the laser spot (about 1ILm). Here 1008 in the figure
100C is a protective film that holds the magnetic film 100b, and 100C is a glass or plastic substrate.

In addition, to reproduce the recorded information signal, the information signal recorded on the magnetic film 100b is reflected by changing the direction of magnetization by injecting a laser beam of a certain intensity using the interaction between light and magnetism called the magnetic Kerr effect. This is done by detecting the rotation of the polarization plane of the laser beam.

The magnetic Kerr effect is when linearly polarized laser light is incident on a perpendicularly magnetized film, the polarization plane of the reflected light changes according to the direction of magnetization.
This is a phenomenon of rotation to the left or right. This rotation is converted into a change in light amount by an analyzer to reproduce the information signal.

In this method, when rewriting the contents of the recorded information signal, the direction of the magnetic field generated by the bias magnet 104 is reversed (
(downward), the laser beam is continuously irradiated without modulation,
After so-called erasing is performed to uniformly align the direction of magnetization of the magnetic film 100b downward, an information signal is recorded using the procedure described above.

In other words, in the optical modulation recording system that is in practical use, it is necessary to erase the original signal when rewriting the information signal, and it is necessary to directly overwrite the new information signal on top of the original information signal. I can't.

In response to this, recently a device has been proposed that allows direct overwriting of information signals using magnetic field modulation recording. (For example, Japanese Journal of AppIl
ed Physics, Vol. 26 (1987) Su
pplement 2B-4゜“old gh 5peed
Overwritable Magneto-Opti
The recording principle of this method will be explained with reference to FIG.
The light is focused on the top. When the temperature of the portion (spot) irradiated with the laser beam increases and reaches the Curie temperature or higher, magnetization reversal becomes easy. On the other hand, a magnetic head 108 is provided on the floating slider 107, and flies while maintaining a space of 1101L or less between it and the surface of the disk 100.

However, in order to prevent the magnetic film 100b from being damaged by the flying slider coming into contact with the disk surface or by getting dust involved, a special protection l1100a containing filler or the like is provided on the disk 100. The 6 magnetic heads 1.08, which are more durable than the disk protective film used for optical modulation recording, receive a current of 4 # and lees from the magnetic head try circuit 109. The direction of the generated magnetic field is reversed depending on the information signal. To record information signals at high speeds, it is necessary to downsize the magnetic head and bring it close enough to the disk, so unlike the optical modulation method described above, magnetic field modulation recording requires the magnetic head to be placed on a floating squiter. #Precepts are desirable.

In the magnetic film 100b, the temperature rises only at the laser beam irradiation position, and magnetization is formed in the same direction as the magnetic field generated by the magnetic head 108, and as the disk 100 rotates, after passing the laser beam irradiation position, The temperature drops rapidly and the magnetization is preserved. In this way, due to the reversal of the magnetic field, the magnetic film 00b has the same size as the laser spot (1
An information signal is recorded by the pattern of the magnetized region (about 100 gm). In this method, when rewriting the contents of the information signal, there is no need for an erasing operation to uniformly align the direction of magnetization once, and by repeating the above operation, direct overwriting is possible any number of times. Furthermore, the reproduction of the information signal is exactly the same as the optical modulation method described above.

In this way, there are optical modulation type magneto-optical recording devices that are in practical use that cannot directly overwrite information signals, and magnetic field modulation type magneto-optical recording devices that have been proposed for the purpose of direct overwriting of information signals. The protective film of the disk, which is the magneto-optical recording medium used, and the structure of the magnetic field applying means are different, making them completely incompatible. In particular, the effective magnetic field range generated by the magnetic field modulation type magnetic head is as small as a diameter of 0.01 mm, and the range of the effective magnetic field generated is 0.05 mm between the irradiated laser spot position and the irradiated laser spot position.
Precise positioning on the order of mm is required. Therefore, if both a large bias magnet for optical modulation and a small magnetic head for magnetic field modulation are separately provided and their positions are mechanically replaced depending on the type of disk used, it is necessary to use a large moving mechanism, especially The positional accuracy of 0.05 mm between the laser spot and the magnetic head of the magnetic field modulation method described above cannot be guaranteed with respect to the moving mechanism in the horizontal plane with respect to the disk surface. Furthermore, when the bias magnet for optical modulation method and the magnetic head for magnetic field modulation are separately provided in this way, there is a problem that the entire device becomes larger.

[Object of the Invention] The present invention was made based on the above circumstances, and provides a magneto-optical recording medium for magnetic field modulation recording that can be directly overwritten with a magneto-optical recording medium for optical modulation recording without increasing the size of the device. The aim is to provide a magneto-optical recording device that can be used for both.

[Means for Solving the Problems] The magneto-optical recording device according to the present invention, like the conventional magnetic field modulation type recording device, has a magnetic head for magnetic field modulation on the floating slider, and also has a bias near the floating slider. When recording using a magnetic field modulation method, the magnetic field modulation method recording device operates in the same way as a conventional magnetic field modulation method recording device, and when recording using an optical modulation method, the floating slider is brought close to the bias mucket and the bias mucket is operated. , the magnetic field is applied to the magneto-optical recording medium through the floating slider, thereby making it possible to use both types of magneto-optical recording media.

[Example] The operation of the magneto-optical recording apparatus according to the present invention will be explained below with reference to FIGS. 1(a) and 1(b).

(a) shows the operation when recording an information signal using the magnetic field modulation method, and (b) shows the operation when recording the information signal using the optical modulation method. 1 is a laser light source, and 2 is a TRIZ circuit for lighting the laser light source. Laser light is optical system 3
The light is focused onto the magnetic film 4b in the magneto-optical disk 4. 4a is a protective film that protects the magnetic film 4b, and 4c is a glass or plastic substrate. The floating slider 5 is provided with a magnetic core C2 and a magnetic head H. The magnetic core C2 is provided so as to be exposed on the upper or lower surface of the floating slider, and 6 is a trife circuit for driving the magnetic head H. For example, as shown schematically in FIG. 2, a circular groove is machined on the lower surface (the surface facing the disk) of the cylindrical magnetic core C2, which is more powerful than a ferromagnetic material such as ferrite. The winding W may be provided inside the magnetic head H for magnetic field modulation, or the magnetic core C2 and the magnetic head H may be manufactured separately. The bias magnet 7 is fixedly disposed near and above the floating slider 5, separated from the magnetic core C1 and the winding WB. The floating slider 5, in which 9 is a constant current source for driving a bias magnet, is supported by an arm 8, and is floated and travels with a distance of 10 gm or less between the disk surface and the disk surface by means of an elevating means (not shown). It is possible to maintain a distance of 0.1 to Q, 9 mm above the .

When recording using magnetic field modulation method,! $1 As shown in FIG. 1(a), the floating slider 5 flies above the surface of the disk 4. The disk 4 is a disk for a magnetic field modulation system, and a protective film 4a having sufficient strength, lubricating properties, etc. is formed on the surface of the disk to prevent the magnetic film 4b from being damaged by contact with the flying slider 5.

The laser light source 1 emits a constant amount of light by a control signal from the control circuit 10, regardless of the content of the information signal, and by a constant current supplied from the laser light source drive circuit 2. Laser light is made magnetic by optical system 3! ! The light is focused on 4b.

Further, the magnetic head H is supplied with an information signal (and thus a modulated current) from the magnetic head trites circuit 6 in response to a control signal from the control circuit 10, and a magnetic field that changes according to the information signal is generated and applied to the disk 4. B indicates the magnetic flux generated by the magnetic head H.In this way, information signals are recorded in the same manner as in the conventional magnetic field modulation recording method.At this time, no current is supplied to the bias magnet 7. , no magnetic field is generated.Furthermore, when recording by optical modulation method, as shown in FIG. 1(b), the floating slider 5
is held at a distance of 031 to 0.9 mm above the disk 4.

At this time, if the magnetic cores C1 and C2 are configured to be in close contact with each other, the leakage of the magnetic field in the lateral direction is reduced, which not only improves efficiency, but also attracts the magnetic core C2 by the magnetic attraction force of the bias magnet 7. This is convenient because the floating slider 5 is fixed.

The laser light [1] turns on and off the light emission according to the information signal by a current modulated by the information signal supplied from the laser light source drive circuit 2 according to the control signal from the control circuit IO. The laser beam is focused by the optical system 3 onto the magnetic film 4b.

Further, a current is supplied to the bias magnet 7 from a constant current source 9 according to a control signal from a control circuit 10 to generate a steady magnetic field. In addition, the direction of the steady magnetic field can be switched by the bias magnet. B indicates the magnetic flux generated by the bias magnet 7. The steady magnetic field uses the magnetic core C2 on the floating slider 5 as part of the magnetic path, and is applied to the disk 4 from the surface of the magnetic core C2 facing the disk 4, so that the attenuation of the magnetic field strength due to magnetic field divergence is minimized. It is possible to apply a sufficient magnetic field to the disk 4 while limiting the magnetic field. At this time, magnetic head H
does not generate a magnetic field. In this way, information signals are recorded in the same manner as in the conventional optical modulation method recording. Here, the floating slider 5 is held upward, and the disk 4
Since there is no contact with the surface, it is possible to use a light modulating disk 4 whose protective film, which has already been put into practical use, has insufficient performance.

With such a configuration, the magnetic core C on the floating slider 5
2 can be regarded as part of the magnetic core CI of the bias magnet.

Also, when using a bias magnet, magnetic core C1 and magnetic core C2
It is possible to generate a magnetic field on the disk even if they are not in perfect contact with each other for a while.

[Effects of the Invention] As described above, the magneto-optical recording device according to the present invention includes a magnetic head for modulating a magnetic field provided on a flying slider, and
A bias macnet that generates a steady magnetic field is fixedly placed above the floating slider, and when the bias macnet is in operation, the levitating slider is lifted and held upward by about 0.1 to 0.9 mm, and the magnetic field generated by the bias macnet penetrates the floating slider. Since no large moving mechanism is used for the magnetic head for magnetic field modulation, the error in the position of the laser spot due to the vertical movement of the floating slider between the magnetic head for magnetic field modulation and the optical head is zero.
．． It is kept below 0.05mm. Therefore, it is possible to use both optical modulation recording media that have already been put into practical use and magnetic field modulation recording media that can be directly overwritten.

Furthermore, by providing a part of the magnetic core of the bias mucknet on the floating slider, it is not only possible to efficiently apply the magnetic field generated by the high ass mcnet to the medium, but also the magnetic field attraction of the bias mcnet It is possible to fix the position of the floating slider by force.

[Brief explanation of drawings]

FIGS. 1(a) and (b) are diagrams explaining the operation of the magneto-optical recording device according to the present invention, FIG. 2 is a sketch of the magnetic core C2 and the magnetic head of the magneto-optical recording device according to the present invention, and FIG. FIG. 4 is a diagram illustrating the operation of a conventional optical modulation type recording apparatus, and FIG. 4 is a diagram illustrating the operation of a conventional magnetic field modulation type recording apparatus. l... Laser light source 2... Laser light source try circuit 4... Disk 5... Flying slider 6... Magnetic head try circuit 7... Bias magnet 9... Constant current source O...・Control circuit H...Magnetic head C2...Magnetic core Figure 3

Claims (3)

[Claims] (1) In a magneto-optical recording device that records or erases information signals by applying a magnetic field while irradiating a light beam to a magneto-optical recording medium, a first and a second magnetic field generating means that generates a steady magnetic field regardless of the content of the information signal, the first magnetic field generating means is provided on the floating slider, and the second magnetic field generating means is provided on the floating slider. The second magnetic field generating means is arranged near the floating slider, and the steady magnetic field generated by the second magnetic field generating means is applied to the magneto-optical recording medium through the floating slider. Features of magneto-optical recording device. (2) The magneto-optical recording device according to claim 1, wherein at least a part of the magnetic core of the second magnetic field generating means is provided on a floating slider. (3) When the second magnetic field generating means operates, the second magnetic field generating means
3. The magneto-optical recording device according to claim 2, wherein the floating slider is fixed by a magnetic attraction force between the magnetic field generating means and a magnetic core provided on the floating slider.