JPH03216836A - Magneto-optical recorder - Google Patents

Abstract

PURPOSE:To accomplish the switching of an optical modulation system and a magnetic field modulation system by integrally forming a magnetic head for the magnetic field modulation system and a magnetic head for the optical modulation system. CONSTITUTION:A composite magnetic head is formed of the 1st magnetic head capable of modulating the generated magnetic field in accordance with an information signal and the 2nd magnetic head capable of normally generating magnetic field without depending on the content of the information signal and switching the direction of the magnetic field and provided on a floating slider 107. Then, the intensity distributions of the generated magnetic field of the 1st and the 2nd magnetic heads are allowed to be concentrically overlapped on the magnetic film 100b of a disk 100. Thus, the switching of the magnetic field modulation system and the optical modulation system is accomplished just by allowing the composite magnetic head to ascend or descend by <=1mm in a vertical direction with respect to the disk 100.

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 called an optical modulation method is known and has been put into practical use. The recording process 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 loo is uniformly 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 tribe circuit for lighting the laser light source. The laser beam is focused on the magnetic film 1 0 0 b i by the optical system 103 . When a laser beam is irradiated, the area irradiated with the laser beam (spot)
As the temperature increases and reaches above the Cussot temperature, magnetization reversal becomes easier. On the other hand, the high-ass magnet 104 is supplied with a constant DC current from a constant current source 105 and generates a steady magnetic field B directed upward toward the disk surface. Therefore, magnetism II]
On 00b, only the part irradiated with the laser beam reverses its magnetization so that it points upward, passes through the part irradiated with the laser beam, and as the temperature decreases, the magnetization is preserved.

By turning on and off the laser beam, an information signal is recorded in the magnetic Ml0Ob by a pattern of magnetized regions that are approximately the same size (about Igm) as the laser spot.

In the figure, 100a is a protective film that protects the magnetic film 100b, and 100c is a glass or plastic substrate.

Furthermore, to reproduce the recorded information signal, the information signal recorded on the magnetic film 100b due to a change in the direction of magnetization is inputted with a laser beam of a constant intensity using the interaction between light and magnetism called the magnetic force effect. This is done by detecting the rotation of the polarization plane of the reflected laser light.

Magnetic force ~ effect is that when linearly polarized laser light is incident on a perpendicularly magnetized film, the polarization plane of the reflected light or the magnetization direction
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 high-ass 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, the optical modulation recording system currently in use does not allow direct overwriting of information signals.

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 App-1
ied Physics, Vo1.26 (1987)S
UPLEMENT 26-4, “Old GH Speed
Overwritable Magneto-Opt
icRecovdjng'') Description of this method [JX principle will be explained with reference to FIG. The laser beam is focused on the irradiated area (spot).
As the temperature increases to above the Curie temperature, magnetization reversal becomes easier. On the other hand, a magnetic head 108 is provided on the floating slider 107, and there is a magnetic head 108 between it and the surface of the disk 100.
It travels floating while maintaining a space of 0 μm or less.

However, if the floating toss lighter touches the disc surface,
In order to prevent the magnetic film 100b from being damaged by dust being drawn in, a special protective film 100a containing a filler or the like is provided on the disk 100, and is different from the disk used in the optical modulation method described above. In comparison, it has excellent durability. magnetic head 10
8 receives current supply from the magnetic head trites circuit 109, and the direction of the generated magnetic field is reversed in accordance with the information signal. When recording information signals at high speeds, the magnetic head is made smaller.
Because it is necessary to bring the magnetic head sufficiently close to the disk, it is preferable for magnetic field modulation type recording to have a structure in which the magnetic head is provided on a flying slider, unlike the above-mentioned optical modulation type recording.

In the magnetic film 100b, the temperature increases only at the laser beam irradiation position, and magnetization is formed in the direction of the magnetic field generated by the magnetic head 108 and the direction of rotation, and as the disk 00 rotates, after passing the laser beam irradiation position, When the temperature suddenly drops, the magnetization is preserved. In this way, due to the reversal of the magnetic field, the magnetic film 100b has the same size as the laser spot (1
Information signals are recorded based on the pattern of magnetized regions (on the order of pm). 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, it is possible to directly overwrite the information signal as many times as necessary. 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 0.2 tnm in diameter, and the range between the irradiated laser spot position and the irradiated laser spot position is 0.0 tnm.
Precise positioning of about 5mm is required. Therefore, in the case where both a large optical modulation type high-ass macnet and a small magnetic field modulation magnetic head are separately provided and their positions are mechanically switched depending on the type of disk used, a large moving mechanism is required. In particular, with a moving mechanism in a plane horizontal to the disk surface, 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. Furthermore, when the high-assembly net for optical modulation 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 has been 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] A magneto-optical recording device according to the present invention includes a composite magnetic head integrally formed with a first magnetic head for magnetic field modulation recording and a second magnetic head for optical modulation recording. There are things that I have. The intensity distribution of the magnetic field generated by the first magnetic head and the intensity distribution of the magnetic field generated by the second magnetic head are configured to overlap concentrically, and the center position of the laser spot on the magneto-optical recording body is 0.05m in advance so that it almost coincides with the center position of the magnetic field distribution generated by the first and second magnetic heads.
By adjusting the accuracy to about m, the first and second
It is possible to use both magnetic heads separately without installing a large movement mechanism that would impair the relative positional accuracy between the magnetic head and the laser spot position (relative positional accuracy in the horizontal plane with respect to the medium surface). Therefore, it is possible to combine the recording function of the conventional optical modulation method and the recording function of the magnetic field modulation method, which allows direct overwriting, with a simple configuration.

[Examples] Examples of the present invention will be described below with reference to FIGS. 1 to 3.

Figure 1 (A). (B) is a diagram illustrating the configuration and operation of the magneto-optical recording device according to the present invention. Further, for details of the flying sliver having a magnetic head, cross-sectional shapes are shown in FIGS. 3(A) to 3(D). 3(A) to 3(D) show different embodiments, each of which shows a first magnetic head Hl capable of modulating the generated magnetic field according to an information signal, and a steady magnetic head H1 that is not dependent on the content of the information signal. A second magnetic head H2 or a composite magnetic head capable of generating a magnetic field and switching the direction of the magnetic field is formed, and a composite magnetic head or a floating slitter 1 is formed.
This is a configuration provided on the 07. The composite magnetic head consists of a core C made of a soft magnetic material such as ferrite and a coil COI, C:02 wound around the core C.

The coil COI constitutes a magnetic head Hl, and the coil CO2 constitutes a magnetic head H2. Figure 3 especially (C) shows the coil COI
An embodiment is shown in which a thin film is formed on the magnetic pole end surface of the core C.

In addition, the embodiments shown in FIGS. 3A to 3C are either the core C of the composite magnetic head made of soft magnetic material or the floating slider 10.
7 is formed integrally with 7, whereas as shown in FIG. 3(D), it is made of ceramic or other material.
A composite magnetic head may be attached to the floating slider 107.

As shown in FIGS. 1A and 1B, a flying slider 107 equipped with a composite magnetic head is placed opposite to a laser light source 101 and an optical system 103 with a magneto-optical disk 100 serving as a magneto-optical recording medium interposed therebetween. and is supported by arm 110.

The arm t 1 0 is rotatable around a fulcrum 111 and has a mechanism for raising and lowering the floating slider 107 in a direction perpendicular to the medium surface of the disk 100 . This first
Figure (A). In (B), the floating slider 107 provided with a composite magnetic head has the configuration described in FIG. 3(A).

In this way, the first magnetic head H1 and the second magnetic head H
2 is provided on the floating slitter Iro 7. Further, the floating slider l07 provided with a composite magnetic head by the above-mentioned elevating mechanism is movable in a direction perpendicular to the medium surface of the disk 100, or cannot be moved in a direction horizontal to the medium surface. This is to prevent a shift between the magnetic head and the laser spot position due to movement of the flying slider 107. If the positions of the magnetic head and the laser spot shift in a direction parallel to the medium surface, good recording on the medium will not be possible.

Next, the operation of the magneto-optical recording device according to the present invention will be explained. Figure 1 (A) shows the operation when recording information signals using the magnetic field modulation method. The disk 100 has a particularly durable protective film 100a suitable for the magnetic field modulation method.
is provided on the surface. The floating slider 107 is lowered to the surface of the disk 100 by a lifting mechanism and moves from 5 to 1.
Disk 1 is loaded with a load of 0g but rotates at high speed.
Obtaining buoyancy from the airflow generated by 00, the disk 100
It is in a floating state with a distance of 10 gm or less between the surface of the

In response to a control signal generated by the control circuit 112, the laser light source drive circuit 102 supplies a constant DC current so that the laser light source 101 continuously emits light with a constant amount of light. The laser beam is transmitted through the optical system 103 to the magnetic film 1 in the disk lOa.
The light is focused on 00b. On the other hand, in response to a control signal from the control circuit 112, the magnetic head drive circuit 109 supplies a current modulated by the information signal to the coil COI of the magnetic head H1 for magnetic field modulation recording, and reverses the polarity according to the information signal. Generates a magnetic field. The state of the magnetic field generated at this time is shown in FIG. 2(A).

The in-plane equimagnetic field curves of the magnetic film 100b are concentric circles as shown by hl, and the closer to the center, the stronger the magnetic field. At this time, the center position of the laser beam spot LS is adjusted so as to be approximately at the center of the magnetic field distribution, and efficient recording is possible. Further, the constant current source 113 does not supply current to the optical modulation recording magnetic head H2 according to a control signal from the control circuit 112, and therefore the magnetic head H2 does not generate a magnetic field. Through the above operations, information signals are recorded based on the same principle as described in the description of the conventional magnetic field modulation recording method. With this magnetic field modulation method of recording, as mentioned earlier, it is easy to directly overwrite information signals onto the disk. Next, FIG. 1(B) shows the operation when recording an information signal using the optical modulation method. The protective film 100a of the disc 100 for the optical modulation method, which has been put into practical use, does not have sufficient durability and reliability for the floating movement of the floating slider 107. It is maintained at an interval of 0.1 to 0.9H. The laser light source drive circuit 102 controls the laser light source 101 according to the control signal generated by the control circuit 112.
A current is supplied so that the light emission repeats on and off according to the information signal. The laser beam is focused by the optical system 103 onto the magnetic film 100b in the disk 100.

On the other hand, a control signal from the control circuit 112 causes the magnetic head drive circuit 109 to control the coil Cot of the magnetic head Hl.
No current is supplied to the magnetic head Hl, and the magnetic head Hl does not generate a magnetic field. Further, the constant current source 113 supplies a constant DC current to the magnetic head H2 according to a control signal from the control circuit 112, and the magnetic head H2 generates a steady magnetic field. The state of this generated magnetic field is shown in FIG. 2(B). Magnetism! The in-plane isomagnetic field curve h2 of I100b is concentric, similar to the isomagnetic field curve hi of the magnetic field generated by the magnetic head H1 in the magnetic field modulation method shown in FIG. 2(A), and its position is also the same as the isomagnetic field curve h
This is the position that overlaps with l. In other words, since the center of the magnetic field generated by the magnetic head almost coincides with the center position of the laser beam spot LS, efficient recording is possible.

In this way, information signals are recorded using the same principle as described in the explanation of the conventional optical modulation method recording. As mentioned above, it is difficult to directly overwrite information signals in this optical modulation recording method, or it is possible to use a magneto-optical disk for the optical modulation method that has been put into practical use.

In this way, the magnetic field intensity distribution generated by the magnetic head H1 and the magnetic field intensity distribution generated by the magnetic head H2 on the magneto-optical disk overlap in a substantially concentric circle, and the center of the intensity distribution coincides with the center position of the beam spot. Both magnetic field modulation recording and optical modulation recording can be performed satisfactorily.

[Effects of the Invention] As described above, the magneto-optical recording device according to the present invention includes a composite magnetic head in which a first magnetic head for a magnetic field modulation method and a second magnetic head for an optical modulation method are integrally formed. Since the intensity distribution of the magnetic field generated by the first magnetic head and the intensity distribution of the magnetic field generated by the second magnetic head are configured to concentrically overlap on the magnetic film of the magneto-optical recording medium, It is possible to switch between the magnetic field modulation method and the optical modulation method simply by moving the magnetic head up and down by 1 mm or less in the direction perpendicular to the surface of the magneto-optical recording medium. The effective magnetic field range (magnetic field of the size necessary for recording) of the first magnetic head for magnetic field modulation is at most 0.2 diameter, and the laser beam spot is located within this range by 0.05 mm.
Is there any way to determine the position between the magnetic head and the laser beam spot with an accuracy on the order of milliliter?
The above-mentioned accuracy can be maintained by only raising and lowering the movement of about 1++v, and the entire device can also be made smaller.

With such a small device, it is possible to use both magneto-optical recording media for optical modulation recording that are in practical use and magneto-optical recording media for magnetic field modulation recording that can be directly overwritten.

[Brief explanation of drawings]

FIGS. 1(A) and 1(B) show the configuration of the magneto-optical recording device of the present invention,
Diagrams explaining the operation, Figures 2 (A) and (B) are similar to Figure 1 (A).
). A diagram showing the state of the magnetic field generated by the magnetic head shown in (B), and Figures 3 (A), (B), and (C). (D) is a diagram showing the configuration of the magnetic head of the present invention, FIG. 4 is a diagram showing the configuration of a conventional optical modulation system, and FIG. 5 is a diagram showing the configuration of a conventional magnetic field modulation system. H1... Magnetic head for magnetic field modulation H2... Magnetic head for optical modulation 100... Disk 101... Laser light source 102... Laser light source drive circuit 107... Flying slider 109... Magnetic head drive Circuit 112 ... Control circuit 113 ... Constant current source false) No./B (B) Shame 2 Haze (△) (A) Kan 3 Figure 14 mouth

Claims (2)

[Claims] (1) In a magneto-optical recording device that records or erases an information signal by applying a magnetic field while irradiating a light beam to a magneto-optical recording medium, the means for applying the magnetic field is a magneto-optical recording device that applies a magnetic field according to the information signal. Composite magnetism in which a first magnetic head capable of modulation and a second magnetic head capable of generating a steady magnetic field independent of the content of an information signal and switching the direction of the steady magnetic field are integrally formed. A magneto-optical recording device characterized by having a head. (2) The above-mentioned composite magnetic head is provided on a floating slider and has a mechanism for raising and lowering the floating slider in a direction perpendicular to the surface of the magneto-optical recording medium. In the case of performing optical modulation recording by lowering the slider toward the surface of the magneto-optical recording medium and levitating it while applying a magnetic field with the first magnetic head, the floating slider is 2. The magneto-optical recording device according to claim 1, wherein the magnetic field is applied by the second magnetic head while the magnetic head is raised and held away from the surface of the magneto-optical recording medium.