JPS6318552A - Magneto-optical recording device - Google Patents

Abstract

PURPOSE:To remove the interference of magnetic field and to normally record and erase information by providing a first moving means to move a first optical head and a second moving means to move a second optical head. CONSTITUTION:The first head moving means 81 that moves the first optical head so that its information recording point on one surface of a magneto-optical recording medium is modified along a prescribed, fixed first locus 86, is provided as well as the second head moving means 83 that moves the second optical head so that the head moves along a second locus 88 which is determined preliminarily so that the information recording point of the second optical head on the other surface of the magneto-optical recording medium does not cross with the first within the information recording area of the medium when seen from the direction perpendicular to the surface of the recording medium. Since the second locus 88 is so preliminarily determined as not to cross with the first locus 86 as seen from the direction perpendicular to the surface of the magneto- optical recording medium 10, the information recording point of the first optical head 70 moved by the first transferring means 81, and that of the second optical head 72 moved by the second moving means 83 do not come close to each other in the information recording area of the medium 10.

Description

TECHNICAL FIELD The present invention relates to an apparatus for recording information on a magneto-optical disk.

Prior Art In magneto-optical disks in which information is written by locally magnetizing the magneto-optical recording layer, prior to writing new information, magnetization corresponding to previous information existing at the location where the new information is to be recorded is created. Since a clearing process is required, there is a drawback that the information writing time is longer than that of the overwriting method used in conventional magnetic disks, that is, the override method.

In contrast, magneto-optical recording layers are provided on both sides of the magneto-optical disk, and recording areas that form pairs with each other are provided in the magneto-optical recording layers on both sides of the magneto-optical disk. With the optical head of
While recording new information in one of the paired recording areas where information has been previously erased, the information recorded in the other of the paired recording areas is cleared in preparation for the next recording. A pseudo-override method can be considered.

Problems to be Solved by the Invention However, in such a pseudo-override system, the optical heads disposed on both sides of the magneto-optical disk are usually equipped with magnetic field forming coils for recording or erasing information. When recording new information, a magnetic field for recording new information in a predetermined recording area on one side of the magneto-optical disk is generated from one optical head, and at the same time, a magnetic field is generated on the other side of the magneto-optical disk. A magnetic field is generated from the other optical head for erasing previously recorded information in a recording area that is paired with the recording area. Therefore, when a pair of optical heads are substantially opposed to each other with the magneto-optical disk in between, that is, when the position where information is written by one of the optical heads and the position where information is erased by the other optical head are close to each other, There is a drawback that the magnetic fields formed by both magnetic field forming devices interfere with each other, making it impossible to record or erase information normally.

Means for Solving the Problems The present invention has been made against the background of the above circumstances.
The gist is that a magneto-optical recording medium is provided with magneto-optical recording layers on both sides of a substrate, and a first magnetic field forming device is arranged to face one surface of the magneto-optical recording medium. A first optical head and a second optical head disposed to face the other surface of the magneto-optical recording medium and provided with a second magnetic field forming device, the pair of first optical head and second optical head are respectively provided. In a magneto-optical recording device in which information is recorded in each of the magneto-optical recording layers by an optical head, an information recording point on one surface of the magneto-optical recording medium of the first optical head is set at a predetermined constant point. (2) a first moving means for moving the first optical head such that the information recording point on the other surface of the magneto-optical recording medium by the second optical head is changed along a first trajectory; The second optical head is moved along a predetermined second trajectory so as not to intersect within the information recording location of the magneto-optical recording medium when viewed from a direction perpendicular to the trajectory and the surface of the magneto-optical recording medium. and a second moving means for moving the.

In this way, since the second locus is predetermined so as not to intersect with the first locus when viewed from the direction perpendicular to the surface of the magneto-optical recording medium, the first moving means The information recording point of the first optical head that is moved and the information recording point of the second optical head that is moved by the second moving means do not approach each other within the information recording location of the magneto-optical recording medium. Therefore, the magnetic field generated from the magnetic field forming device of the first optical head and the magnetic field generated from the magnetic field forming device of the second optical head do not interfere with each other.
Information is normally recorded or erased regardless of the relative positions of the optical heads, and the above-mentioned override is reliably made possible.

Here, the magneto-optical recording medium is a disk-shaped magneto-optical disk having magneto-optical recording layers on both sides, and the first moving means and the second moving means preferably include the first optical head and the magneto-optical disk. a common holder that supports a second optical head on both sides of the magneto-optical disk at positions on the outer circumference side and an inner circumference side of the magneto-optical disk; a guide device that guides the holder so that the head moves from the outer circumference side position to the inner circumference side position and from the inner circumference side position to the outer circumference side position, and the first trajectory and the second trajectory They are formed in the radial direction on both sides of the rotation center of the magnetic disk.

Further, the magneto-optical recording medium is a disc-shaped magneto-optical disk having magneto-optical recording layers on both sides, and preferably the first
The moving means moves the first optical head so that the information recording point of the first optical head follows a first locus passing through the rotation center of the magneto-optical disk, and the second moving means moves A second optical head in which the information recording point of the second optical head intersects the first locus at the center of the magneto-optical disk.
The second optical head is moved along the trajectory.

EXAMPLE Hereinafter, an example of the present invention will be described in detail based on the drawings.

In FIGS. 1 and 2, a disk-shaped magneto-optical disk 10 serving as a magneto-optical recording medium is continuously driven to rotate about its axis by a rotary drive motor 12. As shown in FIGS. As shown in detail in FIG. 3, the magneto-optical disk IO includes non-magnetic layers 16 and 18, a first magneto-optical recording layer 20 and a second magneto-optical recording layer 22, a non-magnetic layer 24 and 26, a pair of transparent substrates 28 and 30 are provided in a stacked state. Glass or a transparent resin such as acrylic resin or PMMA is suitably used for the transparent substrates 28 and 30, and the non-magnetic layers 16, 18, 24, 26 include:
Transparent nonmagnetic materials such as aluminum nitride, silicon oxide, silicon dioxide, and silicon nitride are preferably used, and the first magneto-optical recording layer 20 and the second magneto-optical recording layer 22 include amorphous GdTbFe, TbFe, TbFeCo,
Materials having a remarkable magneto-optical effect such as GdCo, GdDyFe, polycrystalline MnCuBi+single crystal TbFe0z, and rare earth iron garnet are preferably used. The bonding layer 14 is made of a well-known adhesive such as a rubber adhesive, and is a transparent substrate on which a non-magnetic layer 24, a first magneto-optical recording layer 20, and a non-magnetic layer 16 are sequentially laminated on the negative side. 28 and a transparent substrate 30 on which a non-magnetic layer 26, a second magneto-optical recording layer N22, and a non-magnetic layer 18 are sequentially laminated on the negative side. Note that, if necessary, a reflective layer such as an aluminum vapor deposited layer may be provided between the bonding layer 14 and the nonmagnetic layers 16 and 18.

A pair of first optical disks 32 and a second optical head 38 are disposed to face one and the other surface of the magneto-optical disk 10, respectively. The first optical helad 32 is fixed to a semiconductor laser element (not shown), an objective lens 34 that focuses the laser beam output from the semiconductor laser element onto one point of the first magneto-optical recording layer 20, and the outer periphery of the objective lens 34. and a first magnetic field forming coil 36 having an annular shape. Similarly, the second optical head 38 also includes a semiconductor laser element (not shown), an objective lens 40 that focuses the laser beam output from the semiconductor laser element onto one point of the second magneto-optical recording layer 22, and an outer periphery of the objective lens 40. and an annular 21st field forming coil 42 fixed to.

A pair of guide rods 4 are provided on the sides of the magneto-optical disk 10.
4.46, a moving block 48 is movably guided in a direction perpendicular to the rotation axis of the magneto-optical disk 10, and a pair of arms 50 and 52 protrude from the moving block 4B to both sides of the magneto-optical disk 10. A holder 53 is provided. The first optical head 32 and the second optical head 38 are supported at the tips of the pair of arms 50 and 52, and are positioned with the center of the magneto-optical disk 10 in between.

The moving block 48 is threaded with a feed screw 56 connected in series to the output shaft of a pulse motor 54, and the first optical head 32 and the second optical head 38 are connected to their first magneto-optical recording layer. 20 and second magneto-optical recording layer 22
information recording point or erasing point, i.e., focal point 58
and 60 are moved along a first locus 62 and a second locus 64, respectively, which are located on a straight line passing through the center of the magneto-optical disk 10. That is, in this embodiment, the pulse motor 54 and the like correspond to a first moving means and a second moving means for moving and positioning the first optical head 32 and the second optical head 38, respectively. As is clear from FIG. 2, the first trajectory 62, which is the moving line of the focusing point 58, and the second trajectory 64, which is the moving line of the focusing point 60, intersect with each other when viewed from the perpendicular direction to the magneto-optical disk 10. For example, the condensing point of the first optical head 32 is located on the magneto-optical disk 10.
When the second optical head is located at the outer circumference of the magneto-optical disk 10, the second optical head 3's focal point 60 is located at the inner circumference of the magneto-optical disk 10.

A large number of concentric tracks or spiral tracks are provided on both sides of the magneto-optical disk 10 so as to intersect with the first locus 62 and the second locus 64, respectively. If a spiral track is provided, the spiral direction on one side of the magneto-optical disk 10 is opposite to that on the other side. magneto-optical disk 1
A large number of recording areas are formed in the trunk on one side of the magneto-optical disk 10, and a large number of recording areas that form pairs with the above-mentioned storage areas are also formed in the tracks on the other side of the magneto-optical disk 10.

When writing new information to the first magneto-optical recording layer 20 in the magneto-optical recording device configured as described above, the write control device 66 drives the pulse motor 54 to control the first optical disc 32 and the first optical disc. 2. Position the optical head 38 on a predetermined track.

Next, in one of the many recording areas on both sides of the magneto-optical disk 10 and cleared in the previous cycle, the optical head, for example, the first optical head 32 side, uses its first magnetic field forming coil 36 to perform a predetermined magnetic field formation. from the first optical head 32 with a magnetic field formed in the direction of
For example, when light modulated in accordance with the information to be recorded is focused toward the magneto-optical recording N20, that part is heated and the previous magnetization is eliminated, and when it is cooled, the magnetization that has already been formed there is removed. Information is recorded by being magnetized in the direction of the magnetic field. At the same time, in accordance with a command from the write control device 66, a magnetic field is formed from the second magnetic field forming coil 42 in a direction to clear the recording area that is paired with the above recording area, and is continuously maintained from the second optical head 38. The laser beam is irradiated onto the recording area, and the previously stored information is cleared by uniformly local magnetizing (perpendicular magnetization in this embodiment) the recording area s3. In the next cycle, on the contrary, new information is stored on the second optical head 38 side, and the recording area is cleared on the first optical head 32 side. In this way, since the above-mentioned operation is repeated every time new information is recorded, there is no need to take time to clear the recording area in which new information is to be recorded in advance when writing information.

Here, the first optical head 32 and the second optical head 38
records or erases information as described above, and these first optical head 32 and second optical head 38
The focal points 58 and 60 of are moved along the first locus 62 and the second locus 64, respectively, while maintaining a constant interval.

Therefore, the first optical head 32 and the second optical head 3
The focal points 58 and 60 of the magneto-optical disk 10 do not come close to each other when viewed from the direction perpendicular to the magneto-optical disk 10, and are generated from the first magnetic field forming coil 36 and the second magnetic field forming coil 42, respectively, when recording or erasing information. The magnetic fields generated do not interfere with each other.

Further, as described above, the magnetic fields generated from the first VA field forming coil 36 and the second magnetic field forming coil 42 do not interfere with each other, so the first optical head 32 and the second optical head 38 can write information independently. Can be done. Therefore, in the magneto-optical recording device configured as described above, the pseudo override method as described above and
Both the normal writing method and the normal writing method can be used selectively.

Note that the magnetic disk 10 on which information is recorded as described above
For example, when reproducing (reading) information from
A laser beam of a predetermined wavelength is made incident on the first magneto-optical recording layer 20 or the second magneto-optical recording layer 22 from a magneto-optical reproducing device, and the reflected light is taken out to perform magneto-optical reproduction of the Kerr rotation angle difference with respect to the incident light. By detecting it in the apparatus, the signals recorded in the first magneto-optical recording layer 20 and the second magneto-optical recording layer 22 are read out separately.

Next, another embodiment of the present invention will be described. In the following description, parts common to those in the above-described embodiments are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIGS. 4 and 5, the first optical head 70
The second optical head 72 is equipped with a first magnetic field forming coil 74 and a second magnetic field forming coil 76 as in the above-described embodiment, and the magneto-optical disk is guided by guide rods 78 and 80 provided at fixed positions. 10 radial directions. Further, the first optical head 70 and the second optical head 72 are screwed together with screw shafts fixed to the output shafts of the first pulse motor 81 and the second pulse motor 83, respectively. Positioning is performed by a second pulse motor 83. That is, the first pulse motor 81 and the second pulse motor 83 correspond to a first moving means and a second moving means for moving the first optical head 70 and the second optical head 72, respectively.

A first locus 86 of the condensing point 82 of the first optical head 70 and a second locus 88 of the converging point 84 of the second optical head 72 extend in the radial direction of the magneto-optical disk 10, and their extension lines extend in the radial direction of the magneto-optical disk 10. intersect at the center of the magneto-optical disk 10. Therefore, in this embodiment as well, the condensing points 82 and 84 of the first optical head 70 and the second optical head 72 do not come close to each other when viewed from the direction perpendicular to the magneto-optical disk 10, and when recording or erasing information. The magnetic fields generated from the first magnetic field forming coil 74 and the second fIi field forming coil 76 do not interfere with each other.

In FIG. 6, the first optical head moving section 90 and the second optical head moving section 92 are moved by guide rods 94 and 96, similar to the first optical head 70 and the second optical head 72 in the above-described embodiment. The magneto-optical recording layer 20 and the second magneto-optical recording layer 22 are guided in the radial direction of the magneto-optical disk 10 by the first optical head moving section 90 and the second optical head moving section 92. The light condensing point formed is controlled by the first locus 86 and the second locus 8 by a pulse motor (not shown) similar to the above-described embodiment.
8 and a first locus 98 and a second locus 100 having the same mutual relationship.

The first optical head moving unit 90 and the second optical head moving unit 92 have the same structure, and as shown in FIG. 7, for example, the objective lens 102 facing the magneto-optical disk 10 and the first trajectory 98 and second locus 10
Each mirror 104 is provided with a mirror 104 that reflects a ray parallel to zero toward the optical axis of the objective lens 102. On the other hand, the optical head main body 106 provided in a fixed position includes a light source element 108, a collimating lens 1) 0, and a mixing mirror 1.
) 2, etc. are provided, and the beam output from the light source element 108 is transmitted from the mixing mirror 1) 2 to the first modulator 1) 6.
a first trajectory 9 toward the first optical head moving section 90 through the
8 and the second modulator 1)
8 and is launched towards a fixed mirror 1) 4 whose position is fixed. The light emitted toward the fixed mirror 1) 4 follows a second trajectory 100 toward the second optical head moving section 92.
is reflected in a direction parallel to In this embodiment, the first optical head moving section 90 and the optical head main body 106 correspond to the first optical head, and the second optical head moving section 92 and the optical head main body 106 correspond to the second optical head.

According to the present embodiment, the condensing points of the first optical head moving section 90 and the second optical head moving section 92 are located at the first trajectory 98 and the second trajectory 88, which have the same relationship as the first trajectory 86 and the second trajectory 88, respectively. Since it is moved along the trajectory 100, the same effects as the embodiments of FIGS. 4 and 5 can be obtained. Also,
Since the first optical head moving section 90 and the second optical head moving section 92 are only equipped with an objective lens 102 and a mirror 104 as optical components, they have the advantage of being lightweight and allowing high-speed access.

Although one embodiment of the present invention has been described above based on the drawings,
The invention also applies in other aspects.

For example, in the embodiment of FIG.
2 and the second optical head 38, the magneto-optical disk 10
A half mirror 1 detection lens, an analyzer, a photosensor, etc. may be provided to read the information recorded on the half mirror 1.

Also, in the embodiment of FIG. 4, the first trajectory 86 and the second trajectory 88 may be parallel to each other.

In short, it is sufficient that the first locus 86 and the second locus 88 do not intersect at least in the portion where the information is recorded when viewed from a direction perpendicular to the magneto-optical disk 10.

Furthermore, although the magneto-optical disk 10 of the embodiment described above has a single magneto-optical recording layer on both sides, it may also have multiple layers.

Note that the above-mentioned embodiment is merely one embodiment of the present invention, and various modifications may be made to the present invention without departing from the spirit thereof.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams for explaining the configuration of an embodiment of the present invention, with FIG. 1 being a front view and FIG. 2 being a plan view. FIG. 3 is a diagram illustrating the configuration of the magneto-optical disk used in FIGS. 1 and 2. FIG. FIGS. 4 and 5 are diagrams illustrating essential parts of another embodiment of the present invention, with FIG. 4 being a plan view and FIG. 5 being a front view. FIG. 6 is a diagram showing a main part of another embodiment of the present invention. Figure 7 is the 6th
It is a figure explaining the structure of the optical head moving part of a figure. lO: magneto-optical disk (magneto-optical recording medium) 32.70:
First optical head 38.12: Second optical head 62.86, 98: First trajectory 64.88. too: Second trajectory 54: Pulse motor (first moving means and second moving means) 81: First pulse motor (first moving means) 83: Second pulse motor (second moving means) Applicant: Brother Industries, Ltd. Figure 1 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (3)

[Claims] (1) A magneto-optical recording medium having magneto-optical recording layers on both sides of a substrate, and a first optical head disposed to face one surface of the magneto-optical recording medium and including a first magnetic field forming device. and a second optical head disposed to face the other surface of the magneto-optical recording medium and provided with a second magnetic field forming device, the pair of first and second optical heads In a magneto-optical recording device in which information is recorded in each magneto-optical recording layer, a focal point of the first optical head on one surface of the magneto-optical recording medium is arranged along a predetermined constant first locus. a first moving means for moving the first optical head so that the second optical head focuses light on the other surface of the magneto-optical recording medium between the first locus and the magneto-optical recording medium; a second moving means for moving the second optical head along a predetermined constant second locus so as not to intersect when viewed from a direction perpendicular to the plane of the light. Magnetic recording device. (2) The magneto-optical recording medium is a disc-shaped magneto-optical disk having magneto-optical recording layers on both sides, and the first moving means and the second moving means are the first optical head and the second optical head. a common holder that supports the magneto-optical disk at an outer circumferential side position and an inner circumferential side position on both sides of the rotation center of the magneto-optical disk; a guide device that guides the holder to move from the side position to the inner circumferential position and from the inner circumferential side position to the outer circumferential side position,
2. The magneto-optical recording device according to claim 1, wherein the first trajectory and the second trajectory are formed on both sides of the rotation center of the magneto-optical disk. (3) The magneto-optical recording medium is a disk-shaped magneto-optical disk having magneto-optical recording layers on both sides, and the first moving means is arranged so that the light converging point of the first optical head is on the magneto-optical disk. The first optical head is moved along a first trajectory on a straight line passing through the center of rotation, and the second moving means is configured to move the second optical head so that the light converging point of the second optical head is an extension of the first trajectory. 2. The magneto-optical recording device according to claim 1, wherein the second optical head is moved along a second locus located on a straight line intersecting at the center of the magneto-optical disk.