JPS59180802A - Optical magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain the optical magnetic recording and reproduction with high accuracy by setting a flaky auxiliary magnetic pole opposite to a magnetic field generating means of an optical head part by holding a recording medium and therefore avoiding an adverse effect of the magnetic field generating means to an automatic focusing mechanism to a condensing means. CONSTITUTION:A laser beam B made incident to an objective lens 10 is focused and stopped down into a microspot on a magnetic disk 7. Thus the temperature is selectively raised up at the area irradiated by the beam B, and therefore the coercive force of the irradiated area is lowered. Both a magnetic oil 12 and an auxiliary magnetic pole 14 coact to the area S irradiated by said microspot to form a uniform magnetic field along the thickness direction. Therefore only the area S of a magnetic disk 7 is selectively magnetized toward an external magnetic field to form a microbit. The bits are formed for the 1-round course during a revolution of te disk 7. Thus the formation of bits is started to a new track obtained by giving a scan equivalent to a track performed by an optical head part H in the radius direction of the disk 7. In such a way, a microbit is formed at a recording part 7' of the disk 7 with high density and high accuracy in accordance with the input information.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a magnetic recording and reproducing device, and more particularly to a magneto-optical recording and reproducing device that uses light as a writing and reading means.

BACKGROUND OF THE INVENTION A recording head section in a conventional magneto-optical recording/reproducing apparatus is normally constructed as shown in FIG.

In FIG. 1, a magnetic disk 1 serving as a recording medium is fixed to a rotating shaft 2 and is rotatably arranged by a motor 3. As shown in FIG. The magnetic disk 1 is formed of a magnetic thin film having magnetic anisotropy in the thickness direction. The optical head H that irradiates light onto the magnetic disk 1 includes an objective lens 4 that focuses the supplied light onto the magnetic disk 1 in the shape of a minute spot, and an objective lens 4 that focuses the supplied light onto the magnetic disk 1 in the form of a minute spot, and an optical head H that is arranged perpendicularly to the magnetic disk 1, that is, along its thickness direction. It is comprised of a magnetic coil 5 that applies a magnetic field and an actuator 6 that controls the position of these with respect to the magnetic disk 1.

The principle of magneto-optical recording, which is one type of thermomagnetic recording performed by the recording head configured as described above, is as follows. That is, a light beam B modulated and outputted from a light source (not shown) according to input information is focused by an objective lens 4 onto a microspora 1 and irradiated onto the magnetic disk 1, so that the temperature of the irradiated portion increases. increases and the coercive force decreases. However, since an external magnetic field is applied to this portion by the magnetic coil 5 in the thickness direction of the magnetic disk 1,
It heals in that direction and only that part is selectively magnetized.

In this way, minute magnetic domains, ie, bits, are formed on the magnetic disk 1 according to input information, and information is recorded. In this case, in order to form a uniform bit, in addition to maintaining the size of the irradiated minute spot constant and making the temperature distribution of the irradiated area constant, it is also necessary to It is necessary to control each element so that the strength of the magnetic field is also constant. For this reason, for example, actuator 6
A servo mechanism or the like is incorporated in the optical head H to closely follow the subtle vertical movements and irregularities on the surface of the opposing magnetic disk 1 to maintain a constant distance W between these two surfaces with high precision to create a light spot for irradiation. An autofocus mechanism is used to keep the size constant.

However, the weight of the optical head H is quite heavy due to the attachment of the objective lens 4, magnetic coil 5, etc., and as a result, the ability of the optical head H to follow the magnetic disk 1 becomes slow, making it difficult to adjust the facing distance W with high precision. It is difficult to secure. Further, the magnetic field formed by the magnetic coil 5 has an adverse effect on the servo mechanism built into the actuator 6, contributing to the occurrence of errors. Furthermore, since a relatively large current is applied to the magnetic coil 5, the amount of heat generated is large and has an adverse effect on the objective lens 4, but the error caused by this cannot be ignored.

Purpose The present invention has been made in view of the above points, and provides magneto-optical recording which avoids the negative influence of the magnetic field generation means on the autofocus mechanism of the focusing means and enables highly accurate magneto-optical recording and reproducing processing. The purpose is to provide a regeneration processing device.

Configuration The configuration of the present invention will be explained below based on specific examples. FIG. 2 is a schematic diagram showing a recording section of a magneto-optical recording reciprocating device to which the present invention is applied. In FIG. 2, a disk-shaped magnetic disk 7 serving as a recording medium is fixed to a rotating shaft 8 and is mounted so as to be rotatable by a motor 9. As shown in FIG. The magnetic disk 7 is made of 7bFe, GdTbFe, T
It is made of an amorphous magnetic material such as bFeCo and has perpendicular magnetic anisotropy in the thickness direction.

For example, in this example, on the lower side of the magnetic disk 7 in the figure, an optical beam B supplied from a light supply means (not shown) equipped with a light source is focused and squeezed onto the magnetic disk 7 into a minute spora I shape. A 1° objective lens for irradiation is provided. This objective lens 1o is held by a base 11, and this base 11
A magnetic coil 12 is attached to the magnetic disk 7 to apply an external magnetic field perpendicular to the thickness direction of the magnetic disk 7, thereby forming an optical head section H. Furthermore, this optical head portion H is provided on the base body 11.
An actuator 13 is provided which causes the optical head section H to scan the magnetic disk 7 in a predetermined direction in a stepwise manner in the radial direction of the magnetic disk 7.

The actuator 13 also includes a servo m that controls the distance W between the optical head H and the magnetic disk 7 to a constant distance with high precision.
The autofocus mechanism is installed internally, and is configured to take advantage of the effects of the autofocus mechanism described above. That is, by sensitively detecting subtle vertical movements and irregularities on the surface of the magnetic disk 7, the optical head section H
The position is feedback-controlled, and the distance W between the two is maintained at a constant distance with high precision. In addition, as a light source (not shown),
Laser light such as an Ar laser, a He-Ne laser, or a semiconductor laser is suitable.

An auxiliary magnetic pole 14 is disposed on the opposite side of the optical head H with the magnetic disk 7 interposed therebetween.

As shown in FIG. 3, the auxiliary magnetic pole 14 is formed into a thin piece of soft magnetic material, and its longitudinal end surface 1
The optical head 4a is arranged so as to face the magnetic disk 7 and to extend its longitudinal direction along the radial direction of the magnetic disk 7, that is, the scanning direction of the optical head section H. here,
The thickness dimension a is sufficiently smaller than the diameter of the magnetic pole surface 12a of the magnetic coil 12 that covers and sandwiches the magnetic disk 7, and the length dimension ρ is at least the recording portion 7' of the magnetic disk 7.
It is necessary to form the auxiliary magnetic pole 14 so that it is longer than the radial width P of It becomes possible to form a magnetic field in the thickness direction of the magnetic disk 7. That is, as shown in FIGS. 4 and 5, when the recording head section is viewed from the front and side, - the lines of magnetic force emitted from the magnetic coil 12 pass through the magnetic disk 7 and reach the end surface 14a of the auxiliary magnetic pole 14 on the opposite side. Since the magnetic flux is focused, the magnetic flux density is higher and more uniform in the thickness direction in the desired target area of the magnetic disk 7, that is, in the spot irradiation area, than in the case where the auxiliary magnetic pole 14 shown in FIG. 6 is not provided. A strong magnetic field can be created. Therefore,
It is possible to reduce the number of windings of the conductive wire of the magnetic coil 12 as a magnetic field generating means, thereby reducing the weight of the optical head H and improving its ability to follow the surface of the magnetic disk 7. Further, as shown in FIG. 5, since the lines of magnetic force are concentrated in the vertical direction in the figure, a stable and uniform magnetic field is applied without being affected by vertical movement or unevenness of the surface of the magnetic disk 7. This makes it possible to always accurately form uniform bits without adjusting the magnetic field in response to changes in the relative position of the auxiliary magnetic pole 14 with respect to the magnetic disk 7.

Furthermore, by reducing the size of the magnetic coil 12, the adverse effects of the generated heat and magnetic field are reduced, the accuracy of the autofocus mechanism is improved, and more accurate magneto-optical recording processing becomes possible.

The operation of this embodiment configured as described above will be explained below.

For example, l-
The 1e-Ne laser beam B is supplied to the objective lens 10 through optical elements such as various mirrors.

The laser beam B incident on the objective lens 10 is focused there and is focused onto the magnetic disk 7 in the form of a minute spot. As a result, the temperature of the irradiated portion of the micro spot increases selectively, and the coercive force decreases. However, in the irradiated portion S of this minute spot, the magnetic coil 12 and the auxiliary magnetic pole 14 cooperate to form a uniform magnetic field along the thickness direction. Therefore, the irradiated portion S of the magnetic disk 7
are selectively magnetized along the direction of the external magnetic field, forming tiny bits. In this case, the position of the light head H whose weight has been reduced is controlled with high precision by an autofocus mechanism, and the size of the irradiated spora t-S is always maintained constant. Further, a highly concentrated external magnetic field is uniformly applied to the irradiated portion S. Therefore, bits can be stably and extremely accurately formed regardless of slight vertical movements or irregularities on the surface of the magnetic disk 7.

In this way, when the bit formation for one round course (one track) is performed during one rotation of the magnetic disk 7, the optical head H scans one track in the radial direction of the magnetic disk 7 and creates a new bit. Bit formation on the track begins. As described above, minute bits corresponding to the input information are accurately formed in the recording portion 7' of the magnetic disc with high density.
Recording of information is completed.

In the above embodiment, an auxiliary magnetic pole having a long magnetic pole surface that can cover the entire scanning area of the optical head H is fixed, but the auxiliary magnetic pole is not limited to this. It is also possible to have a configuration in which both of them are left facing each other and scan in a predetermined direction in synchronization.

Further, the present invention is also applicable to a magneto-optical recording/reproducing apparatus in which the optical head section H is used as a head for both recording and reproduction.

Effects As detailed above, according to the present invention, by arranging the flaky auxiliary magnetic pole to face the magnetic field generating means of the optical head section with the recording medium sandwiched therebetween, the magnetic field generating means can be miniaturized and the weight of the optical head section can be reduced. is reduced, improving autofocus function. Further, the adverse effects of the heat and magnetic field generated by the magnetic field generating means on the autofocus mechanism are also suppressed. Furthermore, the external magnetic field is formed with high density along the thickness direction of the recording medium. Therefore, the temperature distribution and magnetic field of the spot irradiated portion of the recording medium are kept uniform at all times with high precision, making it possible to form accurate bits, that is, to stably perform magneto-optical recording and reproducing processing. It should be noted that the present invention should not be limited to the specific embodiments described above, and it goes without saying that various modifications can be made within the technical scope of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a conventional magneto-optical recording/reproducing device, FIG. 2 is a schematic diagram showing an embodiment of the present invention, FIG. 3 is a perspective view showing an auxiliary magnetic pole 11, and FIG. FIG. 5 is a front view and a side view showing a recording head section according to an embodiment of the present invention, respectively, and FIG. 6 is a front view showing a conventional recording head section. (Explanation of symbols) 1.7: Magnetic disk 4.10: Objective lens 5.12: ! 1st coil 14: Auxiliary Fi1 pole No. 11J No. 3 1゛yu, 1

Claims (1)

[Claims] 1. A recording medium comprising a magnetic thin film with magnetic anisotropy;
A light supply means including a light source; a condensing means for focusing the light supplied from the light supply means on the magnetic thin film in a spot shape; and an auxiliary magnetic pole disposed to face each other on opposite sides sandwiching the magnetic field generating means and the recording medium, the width dimension of the opposing magnetic pole surface of the auxiliary magnetic pole being A magneto-optical recording generator characterized in that a dimension corresponding to the width dimension of the opposing magnetic pole surface of the magnetic field generating means is sufficiently smaller. 2. In the above item 1, the auxiliary magnetic pole is fixed so that the longitudinal direction of the opposing magnetic pole surface extends in the moving direction of the magnetic field generating means, and the longitudinal dimension is at least as large as that of the recording medium. A magneto-optical recording/reproducing device characterized in that the length is longer than the length in the longitudinal direction of the spot irradiation area by the light condensing means.