JPH01276455A - Magneto-optical disk device - Google Patents

Abstract

PURPOSE:To cause a magnetic field generating part for magnetic field impression to be compact and light and to reduce energy consumption and heating quantity to be needed for the changing and moving of the magnetic field generating part by supporting the magnetic field generating member of a magneto- optical disk with being movable respectively in the radius direction and thickness direction of the disk. CONSTITUTION:A carriage 33, with which an optical pick-up optical system 32 itself to be provided to an optical disk 31 is positioned on the lower surface of the disk 31 and seek-moved by a driving source in the disk radius direction, a second beam splitter 35 and a photo-detecting element for track signal detection are provided on a base 36. A magnetic head 41 is arranged as the magnetic field generating member in the upper side of the disk 31 and a coil is wound to the central leg of a magnetic path material, which is almost mountain-shaped in a head 41. Then, the direction of a current to the coil is changed and the magnetic field of recording/erasing is impressed to the disk 31. This, head 41 is fitted to the tip of an oscillating member 42 and supported with being freely movable in the radius direction and thickness direction of the disk 31.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a magneto-optical disk device capable of recording/reproducing/erasing information.

BACKGROUND OF THE INVENTION Conventionally, a magneto-optical disk device of this type has been configured as shown in FIG. 10, for example. First, a laser beam emitted from a semiconductor laser 1 is collimated by a coupling lens 2 and then beam-shaped by a beam shaping prism 3. Thereafter, the beam is reflected by the roof prism 4 toward the first beam splitter 5, and by the first beam splitter 5, it is reflected toward the second beam splitter 6. The direction of this reflection is toward the magneto-optical disk 7, and the objective lens 8 focuses the light into a minute spot. The reflected light from the magneto-optical disk 7 passes through the objective lens 8 again, a part of which is reflected by the second beam splitter 6, and further reflected by the first beam splitter 6.
The beam splitter 5 separates the beam from the incident light. The detection light separated by the first beam splitter 5 is made into convergent light by a condensing lens 9, and is divided into two parts by a Knifezi prism 10 into one for focus detection and one for detecting a magneto-optical signal.

First, a light beam for focus detection that travels straight toward the Naifezi prism 10 is reflected by a mirror 11 and directed toward a focus detection light receiving element 12, where a focus signal is detected by the well-known Naifezi method and is provided for focus servo. . On the other hand, the light for detecting the magneto-optical signal reflected by the Naifezi prism 10 passes through the λ/2 plate 13 and the Wollaston prism 14, and is imaged on the two-split light receiving element 15, and the magnitude of the p-polarized light/s-polarized light component is The magneto-optical signal is detected. Note that a light receiving element (not shown) for detecting a track signal is arranged below the second beam splitter 6, and the track signal is detected by the light reflected from the magneto-optical disk 7 and transmitted through the second beam splitter 6. Detected.

22. As shown in FIG. 11, the magneto-optical disk 7 is set on a turntable 16 and rotated by a spindle motor 17. The optical pickup optical system described above has a separated optical pickup configuration in which it is divided into two parts, a fixed optical system 18 and a carriage 19, which is a moving optical system, as shown in FIG. The carriage 19 is driven to seek back and forth in the radial direction of the magneto-optical disk 7 by roller members 20 and the like, and is equipped with an objective lens 8, a second beam splitter 6, and a light receiving element for detecting track signals. The remaining optical members are housed in a fixed optical system 18 whose position is fixed.

In such a magneto-optical disk device, in order to write information to the magneto-optical disk 7 or erase written information, a magnetic field is applied to the magneto-optical disk 7, and an objective lens 8 is placed at the location where the magnetic field is applied. The system is designed to irradiate a minute spot laser beam. That is, the magnetization is made easily reversible by laser light, and information is written or erased depending on the direction of the applied magnetic field.

Therefore, in a magneto-optical disk device, the magneto-optical disk 7
A magnetic field generating member, a so-called magnetic head, is required to apply a magnetic field to the magnetic field.

Therefore, conventionally, a magnetic head 21 is provided on the upper surface side of the magneto-optical disk 7, as shown in FIGS. 10 and 11. This magnetic head 21 has an electromagnetic structure in which a coil 23 is wound around a magnetic path material 22 having a mountain-shaped shape, for example, and the direction of the magnetic field shown by the arrow in FIG.
It changes depending on the direction of the current flowing through. Also, when the width of the recording area of the magneto-optical disk 7 is W, this magnetic head 2
1 has a length that can generate a magnetic field over the entire recording area W, and is arranged in correspondence with the seek movement direction of the carriage 19. In other words, it is arranged so that at least a magnetic field can be applied to the minute spot irradiation position by the objective lens 8.

However, this conventional method has the following drawbacks. First, because it is necessary to be able to apply a magnetic field over the entire recording area of the magneto-optical disk 7, the size of the magnetic head 21 should be set to a length equivalent to the width W of the recording area (
It requires a size approximately equal to the radius of the magneto-optical disk 7, resulting in a large disk. Second, since it is generally necessary to apply a magnetic field of about 300 to 500 (Oe) to the recording surface of the magneto-optical disk 7, the coil 2 of the magnetic head 21
3. The number of turns must be increased. From this point of view,
The magnetic head 21 also increases in size in terms of the width in the circumferential direction of the magneto-optical disk 7 and the height in the thickness direction of the magneto-optical disk 7. Thirdly, due to the number of turns of the coil 23 and the current, the amount of heat generated by the magnetic head 21 increases, and the temperature inside the drive device increases sharply. As a result, this becomes a cause of performance deterioration due to temperature changes in the optical components and deformation such as warpage of the magneto-optical disk 7.

Fourth, a motor with high power consumption is required to move the magnetic head 21. First, it is necessary to perform a loading operation to guide the magneto-optical disk 7 onto the turntable 16 in the drive device. During such a loading operation, the magnetic head 21 also assumes the position shown by the solid line in FIG. 12, and after the disk is chucked. It is necessary to move up and down in the disk thickness direction so as to take the position shown by the imaginary line. That is, the magneto-optical disk 7 is connected to the turntable 16.
During the loading operation, which is placed on or discharged,
The magnetic head 21 must be located at the retracted position as shown by the solid line so as not to interfere with the movement of the magneto-optical disk 7 or damage it. On the other hand, when the magneto-optical disk 7 is chucked on the turntable 16 as shown by the imaginary line, the magnetic head 21 is moved as shown in FIG. As shown by the imaginary line, it is necessary to face the surface of the magneto-optical disk 7 with a gap set therebetween.

For this reason, a driving source such as a motor is required to move the magnetic head 21 up and down, but as described above, the size of the magnetic head 21 has become larger and its weight has increased. The moving force for displacement also increases. Therefore, if a motor with this displacement is used, a motor with large power consumption will be required.

Purpose The present invention was made in view of the above points, and aims to reduce the size and weight of a magnetic field generating member for applying a magnetic field to a magneto-optical disk, and to reduce the power consumption and heat generation required to drive the displacement of the magnetic field generating member. It is an object of the present invention to provide a magneto-optical disk device which is capable of reducing the size of the entire device.

Structure In order to achieve the above object, the present invention includes a magnetic field generating member that applies a magnetic field to a magneto-optical disk, and an optical pickup optical system that moves in a radial direction of the magneto-optical disk. In a magneto-optical disk device for optically recording information on a magneto-optical disk, or reproducing or erasing information recorded on the magneto-optical disk, the magnetic field generating member is arranged in two directions, one in the radial direction and the other in the thickness direction of the magneto-optical disk.
A swing member is provided to support the magnetic field generating member individually in a direction, and a drive source is provided that is separate from a drive source for the optical pickup optical system and drives the magnetic field generating member to displace via the swing member. It is characterized by:

That is, by supporting the magnetic field generating member so that it can move freely in the radial direction and thickness direction of the magneto-optical disk by the swinging member, the magnetic field generating member itself does not need to have a size that spans the width of the recording area of the magneto-optical disk. , since it can be made smaller, the burden on the drive source etc. can be reduced.

A first embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

First, an optical pickup optical system 32 is provided for the magneto-optical disk 31 . This optical pickup optical system 32
The structure itself is similar to that shown in FIG. 10, etc., and a carriage 33 (located on the lower surface of the magneto-optical disk 31 and moved in the disk radial direction by a drive source (not shown))
An objective lens 34, a second beam splitter 35, and a light receiving element for detecting track signals (with built-in light receiving element) are provided on a base 36. The description of the fixed optical system side will be omitted. 37 is a roller member.

On the other hand, a magnetic head 41 as a magnetic field generating member is provided above the magneto-optical disk 31 . This magnetic head 41 has a structure similar to the magnetic head 21 shown in FIG. 10, in which a coil is wound around the center leg of a substantially mountain-shaped magnetic path material, and by changing the direction of the current to the coil, A magnetic field for recording/erasing is applied to the magneto-optical disk 31. However, in terms of size, the magnetic head 41 of this embodiment does not have a length corresponding to the width W of the recording area of the magneto-optical disk 31, but has a length that is extremely short compared to the width W. ing.

The magnetic head 41 is attached to the tip of the swinging member 42 and is supported so as to be movable in the radial direction relative to the magneto-optical disk 31 and movable in the thickness direction of the magneto-optical disk 31. .

The swinging member 42 includes a first arm 43 extending in the radial direction to which the magnetic head 41 is directly attached, and a first arm 43 that directly attaches the magnetic head 41.
3 (orthogonal to the moving direction of the carriage 33).

Here, the other end of the second arm 44 is rotatably supported via a rolling bearing 46 with respect to a first shaft 45 perpendicular to the base 36 . That is, the magnetic head 41 moves around the first axis 45 together with the swinging arm 42 and the magneto-optical disk 41.
It can move in the radial direction (strictly speaking, it is an arc movement). Further, a voice coil type linear motor 47 is provided as a drive source for rotationally displacing the second arm 44 in the horizontal plane in this manner. This linear motor 47
A coil 48 made of wire attached to the tip of the other end of the arm 44
, a fan-shaped yoke 49 (inner yoke 49a, outer yoke 49b) disposed at the other end of the second arm 44 so that the coil 48 can cross the magnetic flux; and a magnet 50 attached to the inside of the yoke 49. It becomes more.

As a result, the magnetic flux crosses the coil 48, causing the second arm 44, and hence the swinging member 42, to rotate in a horizontal plane with the first shaft 45 as a rotational fulcrum, thereby moving the magnetic head 41 in the radial direction of the magneto-optical disk 41. It will be moved and displaced.

At this time, it is necessary for both to move so that the position of the magnetic head 41 always corresponds to the position of the objective lens 34. For this reason, an arc-shaped linear scale 51 is attached to a part of the second arm 44, and a reflective sensor 52 attached to the base 36 side compares the rotational position and therefore the position of the magnetic head 41, and the drive system It is configured to track the position by giving feedback to the position.

On the other hand, the first shaft 45 is not fixed on the base 36, but can be freely lowered around a second shaft 56 provided horizontally on the base 36 by means of a support 55, that is, the second arm 45 When looking at the magnetic head 41, it can be freely displaced in the thickness direction of the magneto-optical disk 41. first,
The second axis 56 is disposed perpendicular to the first axis 45 and along the moving direction of the carriage 33.
5 is integrally fixed to a bearing portion 57 of a second shaft 56. 58 is a rolling bearing. In addition, the tip side of the bearing portion 57 (
The second arm 44 and the opposite side) extend as a plunger arm 59 and are directly connected to a plunger 61 of a solenoid 60 serving as a driving source. This causes solenoid 60
By controlling the current supply to the plunger arm S9, the plunger arm S9 moves up and down, and the first shaft 45 and the swinging member 42 move toward the second shaft 5.
6 as a rotational fulcrum. Therefore,
The magnetic head 41 is driven to be displaced in the thickness direction of the magneto-optical disk 41 . Here, the solenoid 60 is energized and controlled in response to detection of insertion/ejection of the magneto-optical disk 31 into the drive device, and when the magneto-optical disk 31 is set at a predetermined position, the plunger arm 5
9 side is raised, and the magnetic head 41 is attached to the magneto-optical disk 31.
However, by stopping the rotation of the bearing section 57 at this time by bringing the rotation stop arm 63 into contact with the rotation stop section 62, a predetermined distance is created between the magneto-optical disk 31 and the magnetic head 41. It is configured to ensure a gap.

The linear motor 47 is configured so that the coil 48, yoke 49, magnet 50, etc. do not come into contact even if the second arm 44 etc. rotate in the thickness direction of the magneto-optical disk 41. Such a configuration allows both axes 45.
56 are arranged close to each other, this can be easily done without requiring a large space.

According to this embodiment, the magnetic head 41 is connected to the magneto-optical disk 3.
Since the magnetic head 41 is displaced in the radial direction of the disk 1, it is only necessary to match the positional relationship with the objective lens 34, and the magnetic head 41 can be made small. Of course, the power consumption by the drive source (solenoid 60) that drives the magnetic head 41 in the disk thickness direction can be reduced, and the amount of heat generated can also be reduced. Furthermore, the overall device can be made thinner and smaller.

By the way, considering the magneto-optical disk 31 more realistically, it is normally inserted into and removed from the drive device while being housed in a rectangular box-shaped cartridge 65 as shown in FIG. This is because if dirt or dust adheres to the disk surface or if the surface is scratched, it will cause errors during recording/reproducing/erasing operations. Here, since the cartridge 65 is not a completely sealed box and it is necessary to irradiate the recording surface with a minute spot from the objective lens 34 or apply a magnetic field, the shutter guide 66
A slidable shutter 67 is provided, and when the loading chuck is carried out, this shutter 67 moves to open a window 68 so that a part of the magneto-optical disk 31 is exposed to the objective lens 34 and the magnetic head 41. It is composed of Furthermore, the shutter 67 is configured to close when the magneto-optical disk 31 is ejected from the drive device.

Therefore, the objective lens 34 and the magnetic head 41 are
It is necessary to enter the inside of the cartridge 65 from the inside and be located at a position close to the surface of the magneto-optical disk 31. For this reason, the amount of movement of the magnetic head 41 in the disk thickness direction shown in FIG. 2 etc. must also take into account the amount of movement into the cartridge 65. That is, at the same time that the cartridge 65 is inserted into the drive device, the solenoid 60 is actuated to move the magnetic head 41 onto the magneto-optical disk 3.
When the magneto-optical disk 31 is chucked, it is necessary to lower the magnetic head 41 to a position close to the surface of the magneto-optical disk 31 through the window 68. Moreover, the situation is reversed when the disc is ejected. Therefore, the amount of movement is larger than in the case of the magneto-optical disk 31 alone, but since the solenoid 60, which is its driving source, is provided near the second shaft 56, a larger amount of movement can be ensured by the magnetic ped 4. is easy.

Secondly, a linear movement method is conceivable for moving the magnetic head 41 in the disk radial direction, but in the case of a linear movement method, it is necessary to move the entire linear movement mechanism forward and backward relative to the cartridge when loading the cartridge. However, the linear movement mechanism or its driving source becomes large. In this regard, according to the present embodiment, the driving source 47.6o for rotation in two directions is present near the fulcrum (first degree second axis 45, 56) of the swinging member 42, and displacement operation in two directions is provided. Since it is a oscillating motion, the weight of moving parts is small and a small drive source is required.
It consumes less power and is more space efficient.

Furthermore, the drive source for driving the magnetic head 41 to displace in the radial direction of the magneto-optical disk 31 is not limited to the linear motor 47, but may be configured by, for example, a pulse motor. The pulse motor eliminates the need for the linear scale 52, and only requires a sensor for detecting the home position of the magneto-optical disk 31.

Next, a second embodiment of the present invention will be described with reference to FIGS. 5 to 7. In this embodiment, instead of the magnetic head 41, a floating magnetic head 71 is used as a magnetic field applying means. This magnetic head 71 is connected to the magnetic head 41.
and has a tapered portion 72a in a part of the magnetic path material 72 formed in a substantially U-shape with respect to the rotation direction of the magneto-optical disk 31 as shown in FIG. It is lightweight and has a coil 73 wound around the other end. Such a magnetic helad 71 is connected to the second arm 44 forming the swinging member 42.
However, instead of the first arm 43, it is connected and supported by a plate spring 74. More specifically, as shown in FIG. 6, the position of the magnetic head 71 is lower than the position of the second arm 44 (
magneto-optical disk 31 side). Second
The structure after the arm 44 is the same as in the previous embodiment.

In this embodiment, since the magnetic helad 71 is light, it floats due to the air flow generated between the disk and the magnetic head when the magneto-optical disk 31 rotates in the direction shown in FIG. Here, since the gap between the disk and the magnetic head due to air levitation is extremely small, only a few microns, the applied magnetic field can be weakened.
can be made more compact. That is, in the case of a system that attempts to maintain a fixed gap between the magnetic head and the disk as in the above-mentioned embodiment, it is necessary to determine the gap taking into account the surface runout of the magneto-optical disk 31, and the gap due to surface runout must be determined. Since the strength of the applied magnetic field also changes as the gap changes, it is necessary to apply a large magnetic field with some margin, and the magnetic head becomes somewhat larger. In this regard, according to the air floating type magnetic head 71 as in this embodiment, the magneto-optical disk 31
Even if there is surface runout, it follows it, so the gap with the disk surface is always maintained constant. In other words, the strength of the magnetic field applied to the magneto-optical disk 31 does not vary.

Furthermore, a third embodiment of the present invention will be explained with reference to FIGS. 8 and 9. In this embodiment, the magnetic head 41 (or 71
) to the magneto-optical disk 31 in the thickness direction, the drive source of the solenoid 60 is omitted, and the drive is performed by a link mechanism 80 based on the insertion and removal operation of the magneto-optical disk 31 (cartridge 65). It is. Here, in this embodiment, a portion corresponding to the plunger arm 59 in the bearing portion 57 of the first embodiment is shown as an arm 81, and as this arm 81 moves toward and away from the base 36, the Similarly, the second arm 44 and the like are oscillated about the two shafts 56. Here,
The arm 81 is normally biased toward the base 36 by a spring 82, and the magnetic head 41 (or 71) is separated from the magneto-optical disk 31, so that the disk can be inserted and removed.

The link mechanism 80 has a shaft 85a that is guided by a horizontal guide hole 84 formed in a side plate 83, and is connected to an arm 85 that is pushed in by its tip when the cartridge 65 is inserted into the drive device, and to this arm 85 by a shaft 86. and an arm 88 that converts horizontal movement of the arm 85 into vertical movement by having a shaft 88a guided by a vertical guide hole 87 formed in the side plate 83;
The arm 8 is rotatably supported on the side plate 83 by a shaft 89a and converts the movement of the shaft 88a into rotational displacement.
1 and an arm 89 for vertically rotating the robot.

As a result, before inserting the cartridge 65,
The arm 81 supports the magnetic head 4 under the biasing force of the spring 82.
1 (or 71) takes a position away from the magneto-optical disk 31. When the cartridge 65 is inserted as shown in FIG. 8(b), the arm 85 is pushed in and the shaft 88a of the arm 88 is lowered. As a result, the arm 89 is rotationally displaced, and the arm 81 is upwardly displaced against the spring 82. As a result, the magnetic head 41 (or 71) is displaced toward the magneto-optical disk 31 via the swinging member 42. In the case of the magnetic head 41, it is positioned at a position where a predetermined gap is maintained between it and the magneto-optical disk 31. In the case of the magnetic head 71, the magnetic head 71 is positioned at a position where it contacts the magneto-optical disk 31.

According to this embodiment, there is no need for a driving source for the magnetic head in the disk thickness direction, and the link mechanism 80 is
This can be done by

As a result, the magnetic head only needs a drive source in the disk radial direction, and power consumption can be reduced.

Effects As described above, the present invention includes a swinging member that supports the magnetic field generating member so that it can move independently in two directions, the radial direction and the thickness direction of the magneto-optical disk. It is possible to reduce the size and weight by shortening the length in the radial direction, and therefore, the power consumption of the drive source for displacing the magnetic head can also be reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view showing a first embodiment of the present invention, and FIG.
The figure is a schematic side view, Figure 3 is a longitudinal front view near the pivot point,
4 is a schematic plan view showing the cartridge configuration, FIG. 5 is a schematic plan view showing a second embodiment of the present invention, FIG. 6 is a schematic front view of a part thereof, and FIG. 7 is a schematic plan view showing the magnetic head portion. 8 is a schematic front view showing a third embodiment of the present invention, FIG. 9 is a schematic plan view, FIG. 10 is a schematic perspective view showing a conventional example, and FIG. 11 is a schematic side view showing an enlarged view. FIG. 12 is a schematic front view showing the state before and after loading. 31... Magneto-optical disk, 33... Optical pickup optical system, 41... Magnetic field generating member, 42... Swinging member, 47... Drive source, 60... Drive source, 71...・Magnetic field generating member JLL Figure 36 Figure J 7 Figure 35, J, , 10 Figure

Claims (1)

[Claims] a magnetic field generating member that applies a magnetic field to the magneto-optical disk;
and an optical pickup optical system that seeks in the radial direction of the magneto-optical disk, and optically records information on the magneto-optical disk or reproduces or erases information recorded on the magneto-optical disk. In the magnetic disk device, a swinging member is provided that supports the magnetic field generating member movably independently in two directions, a radial direction and a thickness direction of the magneto-optical disk, and is separate from a drive source for the optical pickup optical system. A magneto-optical disk device, characterized in that a drive source for displacing and driving the magnetic field generating member via the swinging member is provided.