JPH04162239A - Recording-reproducing apparatus of information for magnetoopeical recording medium - Google Patents

Abstract

PURPOSE:To make it possible to hold back a vertical motion of a disk part in the vicinity of an objective lens to the focal depth of a focus or below by a construction wherein a field means and a light pickup generating an air viscous flow on the opposite sides of a magnetooptical recording medium are disposed on the opposite sides of the medium, respectively. CONSTITUTION:A field means 2 is constructed so that an air viscous flow is generated between a surface 2a thereof opposite to a magnetooptical recording medium 1 and a surface of the magnetoopitcal recording medium when the magentooptical recording medium 1 rotates, and a pickup 3 is constructed so that the air viscous flow is generated between a surface thereof opposing the magnetooptical recording medium 1 and a surface of the magnetooptical recording medium when the magnetooptical recording medium 1 rotates and that a prescribed gap is maintained between it and the surface of the magnetooptical recording medium. The shapes of the surface 2a of the field recording medium. The shapes off the surface 2a of the field means 2 being opposite to the magnetooptical recording medium 1 and of the surface 3a of the light pickup 3 opposing the magnetooptical recording medium, at least, are formed to be symmetric. According to this constitution, a vertical motion of a magneto optical disk 1 can be held back to the focal depth or below of the focus of the light pickup 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an information recording/reproducing apparatus for a magneto-optical recording medium such as a magneto-optical disk.

[Conventional technology]

Conventionally, information recording and reproducing devices optically record and reproduce information by rotating a rigid disk-shaped information recording medium and irradiating the surface of the information recording medium with a light beam. In this case, a focus servo is applied to irradiate the light beam onto the information recording medium surface as a proper light spot, and
In order to perform this focus servo, a complex control II
1 structure and control circuit.

Therefore, some conventional techniques have been proposed in which a flexible information recording medium is rotated and information is recorded and reproduced without using complicated focus servo means.

For example, in Japanese Patent Application Laid-Open No. 48-81509, a flexible disk is configured to rotate on a fixed plate having two inclined sliding surfaces. The content of the arrangement of the sliding bodies is described.

An air flow is generated between the sliding body and the disk to stabilize the disk so that recording and reproduction by the optical pickup can be performed appropriately.

Furthermore, in Japanese Patent Application Laid-Open No. 2-10568, a lens is similarly provided on one side of a flexible disk, a magnetic head is placed on the other side, and there is a gap between the magnetic head and the disk. The content that led to the creation of air bearings is described. The disk is maintained in a stable state, and the light from the optical head can be stably focused on the disk surface.

[Problem to be solved by the invention]

However, among the above conventional examples, Japanese Patent Application Laid-Open No. 48-8150
The device disclosed in Publication No. 9 is provided with a large fixed plate having a sliding surface, and a groove must be formed in this fixed plate in which a member for moving the sliding body in the disk radial direction is movably disposed. Therefore, there is a problem that the information recording/reproducing apparatus becomes larger. In addition, although flexible disks are used in a curved manner, the center of the disk is supported horizontally, so when the disk rotates, distortion occurs in the middle of the disk radius, which is especially large at the inner circumference of the disk. There is a problem in that it causes vertical vibration.

The device disclosed in Japanese Patent Application Laid-Open No. 2-10568 creates an air bearing only on one side of the flexible disk, so the optical head and the disk that are disposed on the other side of the disk are There is a problem in that it is difficult to maintain an appropriate distance.

The present invention is proposed to solve the above-mentioned problems.
In addition to not using complicated focus servo means, when recording and reproducing information using a flexible disk, the disk part near the objective lens that irradiates the light beam maintains a stable state with as little vertical movement as possible. It is an object of the present invention to provide an information recording/reproducing apparatus for a magneto-optical recording medium that can perform the following steps.

[Means and effects for solving the problems] In order to achieve the above-mentioned object, the present invention mounts a flexible magneto-optical recording medium having a magnetic layer for magneto-optical recording, and a magnetic layer on one side of the magneto-optical recording medium. In an information recording and reproducing apparatus for a magneto-optical recording medium, the field means is arranged on one side and an optical pickup is arranged on the other side for recording and reproducing information. The pickup is configured so that when the medium rotates, an air viscous flow is generated between the surface facing the magneto-optical recording medium and the surface of the magneto-optical recording medium, and the pickup is configured to perform magneto-optical recording when the magneto-optical recording medium rotates. A viscous air flow is generated between the surface facing the medium and the magneto-optical recording medium surface, and
The magneto-optical recording medium is configured to maintain a predetermined distance from the surface of the magneto-optical recording medium, and the shape of at least the surface of the field means facing the magneto-optical recording medium and the surface of the optical pickup facing the magneto-optical recording medium are adjusted. This is an information recording/reproducing device for a magneto-optical recording medium having a symmetrical structure.

As described above, the field means that generates an air viscous flow and the optical pickup are placed on both sides of the magneto-optical recording medium, so the vertical movement of the disk near the objective lens is suppressed to below the depth of focus. It becomes possible.

〔Example〕

FIG. 1 shows a first embodiment of the present invention, in which figure A is a side view and figure B is a plan view. A field coil body 2 and an optical pickup 3 are arranged at corresponding positions with the magneto-optical disk 1 interposed therebetween. The field coil body 2 is used during recording to irradiate a light beam onto the magneto-optical disk l, and generates an external magnetic field in order to raise the temperature of the irradiated area and reverse the magnetization while reducing Hc. . In this way,
Spot-like magnetic domains are recorded. Note that the direction of the magnetic field of the field coil body 2 is changed depending on the direction of the current flowing through the coil, and recording and erasing are performed. On the other hand, optical pickup 3
is for irradiating a light beam when recording information on the magneto-optical disk 1 or when reproducing information.

Although the internal configurations of the field coil body 2 and the optical pickup 3 are not shown in FIG. 1, their external shapes are as shown. In other words, as shown in Figure A, the side surface has a streamlined shape in the direction of rotation of the magneto-optical disk 1 and in the opposite direction, and as shown in Figure B, it has a rectangular shape when viewed from above the magneto-optical disk 1. It is formed. Furthermore, the surfaces 2a and 3a of the field coil body 2 and the optical pickup 3, which face the magneto-optical disk l, are symmetrically formed.

Although the magneto-optical disk 1 is made of a material that can be flexibly deformed, large distortions will occur if it is rotated in a deformed state, so it is rotated while maintaining a horizontal state.

Therefore, the amount of surface runout of the magneto-optical disk during rotation is approximately 50 .mu.-. Of course, the amount of surface runout varies depending on the softness of the magneto-optical disk.

The field coil body 2 and the optical pickup 3 configured as described above are arranged so as to be close to the surface of the magneto-optical disk. Further, when the optical pickup 3 is brought close to the rotating magneto-optical disk l, some of the viscous flow of air generated by the rotation is transferred between the magneto-optical disk 1 and the optical pickup. 3, and the others pass outside the optical pickup 3. In this way, by pressing the optical pickup 3 against the magneto-optical disk 1 to the extent that it does not touch the magneto-optical disk 1, the optical pickup can be maintained at a certain distance from the magneto-optical disk 1. Become.

The above state is caused by the area of the surface of the optical pickup 3 facing the magneto-optical disk 1 that acts as a rectifying plate (the projected area on the magneto-optical disk surface) and the viscous flow between the optical pickup 3 and the magneto-optical disk l. This becomes possible when the ratio of the amount passing between the two and the amount passing outside the optical pickup 3 is a predetermined ratio. If the proportion of the viscous flow passing between the optical pickup 3, which acts as a rectifying plate, and the magneto-optical disk 1 is too small, the rectifying plate will come into contact with the magneto-optical disk 1, and conversely, the rectifying plate and the optical If too much viscous flow passes between the magneto-optical disk 1 and the magnetic disk, the magneto-optical disk 1 will vibrate in the vertical direction. Furthermore, if the projected area of the rectifying plate is too small, the effect of suppressing the vertical vibration of the magneto-optical disk 1 will be reduced, and if the projected area is too large, the viscous flow passing between the magneto-optical disk 1 and the rectifying plate will decrease. This makes it difficult for the magneto-optical disk 1 to become uniform, resulting in vertical vibration of the magneto-optical disk 1.

Therefore, by understanding the parameters of the ratio of the viscous flow rate and the projected area of the rectifier plate, it becomes possible to easily maintain a predetermined distance between the magneto-optical disk l and the optical pickup 3. In this way, the predetermined distance between the optical pickup 3 and the magneto-optical disk 1 can be maintained by using the viscous flow generated by the rotation of the magneto-optical disk 1.
Appropriate focus servo can be performed without providing a complicated focus control means.

Furthermore, the field coil body 2, which is the other rectifying plate, is brought closer to the magneto-optical disk 1 from a position corresponding to the optical pickup 3. Then, similarly, part of the viscous flow of air passes between the field coil body 2 and the magneto-optical disk 1, and the other part passes outside the field coil body 2. In this way, as in the case of the optical pickup 3, a predetermined distance between the field coil body 2 and the magneto-optical disk l can be maintained. In this way, the current plate uses the viscous flow of air from both sides of the magneto-optical disk 1 to maintain a predetermined distance from the magneto-optical disk 1, so it suppresses the vertical vibration of the magneto-optical disk 1. It can be suppressed. Also,
Since the optical pickup 3 and the field coil body 2 are positioned in correspondence with each other with the magneto-optical disk 1 in between, it is possible to improve the stability of the sandwiched portion of the magneto-optical disk 1. An optical pickup 3 and a field coil body 2
This makes it possible to bring the magneto-optical disk closer to the magneto-optical disk 1. In this way, the rectifying plate uses the viscous flow of air from both sides of the magneto-optical disk 1 to maintain a predetermined distance from the magneto-optical disk 1.
It is possible to suppress the vertical vibration of the Further, the thickness of the device in the direction perpendicular to the magneto-optical disk 1 can be reduced.

Note that if the two upper and lower current plates are fixed via one support member 14 as shown in Fig. 6, resonance will occur as is clear from the principle of a tuning fork, so it is recommended that they be supported individually. Configure. Further, the field coil body 2, which is one of the rectifying plates, may be fixed to the magneto-optical disk 1 with a required spacing therebetween.

As described above, this embodiment can perform focus servo without using complicated focus servo means,
Compared to using a conventional rigid magneto-optical disk, it is heavier, slows access speed, requires more power, and increases costs due to the magnet for driving the objective lens and many other components. This eliminates the need for actuators and control circuits for them. Conventionally, the reason for requiring the above-mentioned complicated configuration is that although the magneto-optical disk is rotated by a high-precision spindle motor, the amount of surface runout of the magneto-optical disk is 100%.
In addition, for magneto-optical disks that perform high-density recording, an objective lens with an NAo of 5 or more must be used, and for this reason, the depth of focus must be set to 1μ- and focus servo must be applied. This is because there is.

Furthermore, compared to the case of using a conventional flexible magneto-optical disk, it is possible to eliminate the disadvantages of requiring a large device to support the magneto-optical disk and causing large vertical vibrations of the magneto-optical disk.

FIG. 2 shows a second embodiment of the present invention, which has a coil 2b on the upper surface side of the magneto-optical disk l, a field coil body 2 long in the radial direction of the magneto-optical disk, and An optical pickup 3 having an objective lens 3b is disposed on the lower surface side of the disk l. The magneto-optical disk 1 is rotated by a spindle motor 4 while maintaining a substantially horizontal state. Note that the optical pickup 2 according to this embodiment
is a so-called separate type, which includes an objective lens 3b and a mirror 3.
Only the moving optical system with c moves. The light beam from the semiconductor laser 5 provided in the fixed optical system passes through a beam splitter 6 and the like, and then is bent toward the magneto-optical disk 1 by the mirror 3C and irradiated onto the magneto-optical disk 1. The light beam reflected by the magneto-optical disk 1 returns to the fixed optical system via the mirror 3C, passes through the beam splitter 6 and the polarizing beam splitter 7, and is then received by photodetectors 8a and 8b for signal detection. Note that the photodetector 9 is a servo light receiving element that receives light through a critical angle prism 10.

In the case of this embodiment as well, the field coil body 2 and the optical pickup 3
Each has the function of a rectifying plate, and the magneto-optical disk 1 is rotated by utilizing the viscous flow generated by the rotation of the magneto-optical disk 1.
A predetermined distance between the optical pickup 3 and the optical pickup 3 can be maintained. In addition, the reason why one of the rectifying plates is configured to be long in the radial direction of the magneto-optical disk 1 as in this embodiment is because if it is short as shown in FIG. 7, when the magneto-optical disk 1 is rotated, This is because the vibrations cannot be suppressed. Therefore, as shown in FIG. 2B, at least one of the current plates is configured to be long in the radial direction of the magneto-optical disk l.

FIG. 3 shows a third embodiment of the present invention, in which the current plate is not configured to be long in the radial direction of the magneto-optical disk 1 as in the second embodiment, but auxiliary current plates 11 and 12 are provided. This is an attempt to achieve a similar effect.

In this embodiment, a yoke 2d consisting of a part of a rectifying plate, a field coil body 2 having a coil 2b, and an optical pickup 3
are arranged corresponding to the upper and lower positions of the magneto-optical disk 1 to function as a rectifying plate, and the - side auxiliary rectifier plate 11 is placed on the outer periphery of the magneto-optical disk 1 on the same radius where the field coil body 2 is located. The other auxiliary rectifying plate 12 is disposed at a position corresponding to the auxiliary rectifying plate 11 with the magneto-optical disk 1 interposed therebetween. With this configuration, vertical vibration of the magneto-optical disk 1 can be suppressed in the same way as when a long rectifying plate is provided.

FIG. 4 shows a fourth embodiment of the present invention, in which an iron core 2e and a rotatable permanent magnet 2f are used as the field means. The reason why the permanent magnet 2f is rotatable and the direction of the magnetic pole can be changed is to change the direction of the magnetic field of the magnetic field means during recording and erasing. Further, a cover glass 3d is provided on the objective lens 3b on the surface 3a of the optical pink-up 3 facing the magneto-optical disk l. This is to prevent the viscous flow from being disturbed by the step near the objective lens 3b. In the case of this embodiment, the current plate is configured to be long in the radial direction of the magneto-optical disk 1 as in the second embodiment, or an auxiliary current plate is provided as in the third embodiment to rotate the magneto-optical disk. It goes without saying that it is necessary to suppress vertical vibration of the disk.

FIG. 5 shows a fifth embodiment of the present invention, which is an embodiment applied to an overridable device. In other words, the magneto-optical disk 1 has a two-layer structure including a bias layer and a recording layer.
The recording on the recording layer is erased by the initializing magnet 13 disposed at a position shifted by .degree., but the bias layer is left as is. In this device, the magneto-optical disk 1 is rotated and recorded while being aligned in the direction of the magnetic field of the bias layer at the position where the field coil body 2 is disposed.

The same configuration as the fourth embodiment shown in FIG. 4 can be applied to such an overridable device, and in this embodiment, an initialization magnet 13 having a rectifying effect is further provided, and the magneto-optical disk 1 is rotated in the vertical direction. We are trying to further suppress vibrations.

〔Effect of the invention〕

As described above, according to the present invention, by providing the air rectifying plates at the upper and lower positions of the magneto-optical disk, there is no need to use a complicated focus control mechanism, and even when a flexible magneto-optical disk is used, it is possible to avoid the use of a complicated focus control mechanism, and even when a flexible magneto-optical disk is used, it is possible to avoid the use of air rectifying plates in the upper and lower positions of the magneto-optical disk. The magneto-optical disk can be stabilized. Therefore, the vertical movement of the magneto-optical disk can be suppressed to below the depth of focus of the optical pickup.

[Brief explanation of drawings]

FIG. 1 is a side view and a plan view of a first embodiment of the present invention, FIG. 2 is a perspective view and a side view of a second embodiment of the present invention, and FIG. 3 is a third embodiment of the present invention. 4 is a sectional view according to the fourth embodiment of the present invention; FIG. 5 is a plan view and a sectional view according to the fifth embodiment of the present invention; FIGS. 6 and 7 The figure is a diagram for explaining the problem. 2...Field coil body 3...Optical pickup Figure 1 Figure 3 Figure 4 Figure 5 Procedure Amendment February 1, 1991 Mr. Satoshi Uematsu, Commissioner of the Japan Patent Office 1, Indication of the incident 1990 Patent Application No. 287295 2 Name of the invention Information recording/reproducing device for magneto-optical recording medium 3 Relationship with the case by the person making the amendment Patent applicant (037) Olympus Optical Industry Co., Ltd. 4 Agent 1゜Specifications In the 4th line of page 8 of the book, ``outside the viscous flow of air generated by rotation'' was deleted, and in the 7th line of the same page, ``outside the optical pickup 3'' was changed to ``outside the optical pickup 3 and the field coil body 2.'' Correct the outside to ``.

Claims (1)

[Claims] 1. A flexible magneto-optical recording medium having a magnetic layer for magneto-optical recording is mounted, a field means is provided on one surface of the magneto-optical recording medium, and a field means is provided on the other surface. In an information recording and reproducing device for a magneto-optical recording medium, which is equipped with an optical pickup to record and reproduce information, the field means is connected to a surface facing the magneto-optical recording medium when the magneto-optical recording medium rotates. The optical pickup is configured to generate a viscous air flow between the surface of the magneto-optical recording medium and the surface of the magneto-optical recording medium when the magneto-optical recording medium rotates. A viscous air flow is generated between the magneto-optical recording medium and at least a surface of the field means facing the magneto-optical recording medium and a magneto-optical recording medium of the optical pickup. 1. An information recording/reproducing device for a magneto-optical recording medium, characterized in that its shape is symmetrical with respect to a surface facing the medium.