JP2788334B2 - Magnetic field generation mechanism of magneto-optical recording device - Google Patents

Description

The present invention irradiates a magneto-optical recording medium with a laser beam and applies a magnetic field from the opposite side to magneto-optically record and erase information. The present invention relates to a magnetic field generating mechanism of a magneto-optical recording apparatus.

2. Description of the Related Art When recording and erasing information in a magneto-optical recording apparatus of this type, a laser beam emitted from a semiconductor laser is irradiated onto, for example, a disk-shaped magneto-optical medium, and the irradiation position is determined. A magnetic field generating element such as a permanent magnet or an electromagnet is disposed on the magneto-optical recording medium to apply an external magnetic field to the magneto-optical recording medium in a vertical direction. The magneto-optical recording device is, for example, a disk-shaped magneto-optical recording medium 5 as shown in FIG.
The magnetic field generating mechanism 7 and the optical head 6 are disposed above and below the optical recording medium, respectively, and are configured to be able to be simultaneously moved in the radial direction of the magneto-optical recording medium 5 by the driving mechanisms 71 and 61, respectively. By this movement, a seek to a required track of the recording medium was performed, and a magnetic field generated by the magnetic field generating mechanism, and emitted from the semiconductor laser 62 of the optical head and converged on the recording medium via the objective lens 63. Recording and erasing of information can be performed by a laser beam.

However, in such a configuration, it is necessary to move both the optical head and the magnetic field generating mechanism at the same time, so that the weight of the movable part increases and the structure becomes complicated, and seek operation in processing such as recording and reproduction of information is performed. It is difficult to increase the speed.

Therefore, it has been proposed to arrange a plurality of magnetic field generating units in the magnetic field generating element in the seek direction to cover the recording area and to make the magnetic field generating mechanism fixed. That is, for example, as shown in FIG. 7, a block 8 made of a magnetic material is formed in the magnetic field generating element so as to be long in the radial direction of the recording medium 5, and a number of spiral magnetic coils 81, 82,. Is arranged, only the optical head 6 needs to perform the seek operation, the weight of the movable part can be reduced, and the structure can be simplified. Therefore, the access operation can be speeded up. The magnetic field generating element is usually
The configuration is as shown in the figure. That is, the block 8 is made of a high-permeability, low-loss magnetic material, and winding coils 81, 82,... Are disposed on the surface facing the recording medium. The magnetic field is strongest, and the portion H therebetween has the weakest non-uniform magnetic field distribution. This is inconvenient in securing a stable magnetic field strength required for recording and erasing.

[Problem to be Solved by the Invention] Therefore, it is conceivable to make the interval between the winding coils as small as possible, but there is a structural limit. Therefore, it is conceivable to partially overlap the adjacently arranged winding coils as shown in FIG. 9 or FIG. 10, but both are simply attached to the lower surface of the block, and the center of the magnetic field generated by each winding coil is determined. Since the pole piece is not located in the portion, the gap m between the center position of the generated magnetic field and the recording medium becomes substantially large, and there is a drawback that a sufficient magnetic field strength cannot be ensured. Since every other strength differs, a uniform magnetic field strength cannot be obtained as described above.

[Object of the Invention] The present invention has been made based on the above circumstances, and by devising the configuration of the block of the magnetic field generating element and the winding method of the winding coil, the magnetic field generated by each winding coil of the magnetic field generating element is improved. To provide a magnetic field generating mechanism for a magneto-optical recording device that ensures that the center of the magnetic field is sufficiently close to the recording medium to secure the required magnetic field strength and that the entire magnetic field strength can be made uniform over the recording area. It is.

[Means for Solving the Problems] For this reason, in the present invention, a light from a semiconductor laser is applied to a magneto-optical recording medium, and a magnetic field is generated from a magnetic field generating element having a plurality of magnetic field generating units from the opposite side. In the magnetic field generating mechanism of a magneto-optical recording apparatus for recording and erasing information, the magnetic field generating element is formed of a block of a high-permeability low-loss magnetic material or a high-permeability low-loss magnetic material and a non-magnetic material. Are alternately arranged, and the coil winding portions protruding on both sides in the magnetic field generation direction corresponding to each magnetic field generation portion are formed on the block or the portion of the high permeability low loss magnetic material, and the coil The winding coil is wound around the winding part with a magnetic pole crossing over it.

[Operation] Therefore, the center of the magnetic field generated by each winding coil of the magnetic field generating element can be substantially brought close to the recording medium without complicating the structure, and the magnetic field strength in the seek direction can be reduced. Can be uniform.

Examples Examples of the present invention will be specifically described below with reference to the drawings. In the drawing, reference numeral 1 denotes a block made of a high-permeability, low-loss magnetic material, 2 denotes a conductive coil wound around the block, 3
Is a coil winding portion protruding from the surface A of the block 1,
Reference numeral 4 denotes a coil winding portion protruding from the surface B of the block 1 facing the surface A. In addition, the said lead wire coil 2 with respect to the said block 1 WHEREIN: Both coil winding parts 3,
It is wound with a cross over four.

Such a magnetic field generating element is preferably formed by a manufacturing procedure as shown in FIG. That is, first, a high-permeability, low-loss magnetic material is cut out from a ferrite or the like on a block (FIG. 2A). At this time, the length l in the longitudinal direction of the block 1
Is larger than at least the distance over which the laser emitting / receiving element operates. Next, a plurality of convex portions are formed on one surface (A surface) of the cut block and a surface (B surface) opposed thereto.
That is, the coil winding portions 3 and 4 are formed.

It should be noted that any of the following methods may be employed to form the above-mentioned convex portions. That is, (1) It is formed by a dicing machine having an outer peripheral blade.

(2) Immerse in a wet etching solution to remove unnecessary portions.

(3) An unnecessary portion is removed by a dry etching method such as ion milling.

(4) An unnecessary portion is removed by an assist etching method using a laser beam.

And so on. At this time, it is not necessary that the convex portions formed on the surface A and the surface B have the same shape, but it is desirable that they correspond one to one (FIG. 2B). Then, the lead wire coil is crossed over the convex portion so as to be inserted into the concave portion (gap between the convex portions) 20 formed on the surface A and the concave portion 21 formed on the surface B shifted by one pitch in the longitudinal direction of the block 1. 2 (FIG. 2 (c)). Thus, the magnetic field generating element can be configured. In addition, at this time, the coil-wound portion constituted by the convex portion functions as a magnetic pole approaching the surface of the recording medium,
A generated magnetic field having a substantially large magnetic field intensity can act on the recording layer of the recording medium. In the longitudinal direction of the block, the adjacent conductor coils are in an overlapping state, and the magnetic field can be made uniform.

In this embodiment, since the coil is wound around the convex portion by crossing, the distance between the adjacent convex portions can be made as small as possible, so that the turn position becomes longer by winding the coil diagonally. The disadvantage (decrease in efficiency) can be compensated for by reducing the interval.

FIG. 3 shows the relationship between the magnetic field generating element 10 according to the present invention, the magneto-optical disk-shaped recording medium 5, and the laser emitting / receiving element 6. In terms of the operation, the laser light emitting / receiving element 6 seeks a predetermined track on the recording medium 5 and then moves in a predetermined direction from a magnetic field generating portion closest to a region irradiated with the laser beam. A magnetic field is generated to record or erase the information signal.

According to the experiments of the present inventors, the distance t between the convex portions is t =
A uniform and sufficient magnetic field strength can be obtained with a length of 300 μm, a length m of one side of the protrusion m = 500 μm, a distance x between the magnetic field generating element and the recording medium x = 150 μm, and the number of turns = 20 turns.

FIG. 4 shows another embodiment of the present invention. The main feature here is that the blocks in the magnetic field generating element
A portion corresponding to 31 is made of a high-permeability, low-loss magnetic material, and a portion corresponding to the recess 32 is made of a non-magnetic material. The combination member is alternately connected in the longitudinal direction of the block. In this case, the conductor coil is wound by crossing in the same manner as in the above-described embodiment.

One example of a method for manufacturing such a magnetic field generating element is shown in FIG. Here, first, the thickness of ferrite
Repeating a thin plate 31 of a 500 μm low-loss magnetic material and a rod-shaped non-magnetic material 32 of about 300 μm in thickness, such as glass,
Affix (FIG. 5 (a)). Next, as shown in FIG. 5B, cutting is performed from the dotted line K to form a block. The cut block is shown in FIG. 5 (c). Finally, the conductor coil is wound as shown in FIG. 5 (d). Since the magnetic poles adjacent to each other are separated from each other by a non-magnetic material, the magnetic field generating element configured as described above has an advantage that the magnetic field generation efficiency in the vertical direction becomes extremely high. Furthermore,
Compared with the previous embodiment, since the magnetic path size in each magnetic field generating portion is shorter, the inductance L can be suppressed, and high-speed switching corresponding to a higher frequency signal can be performed.

[Effects of the Invention] As described in detail above, the present invention is configured such that a magnetic field generating element is formed from a block of a high magnetic permeability and low loss magnetic material, or alternatively, a high magnetic permeability and a low loss magnetic material and a nonmagnetic material are alternately arranged. The coil wrapping portion, which is formed of a block and protrudes on both sides in the magnetic field generation direction corresponding to each magnetic field generating portion, is configured in the block or the portion of the high magnetic permeability low loss magnetic material, and the coil wrapping portion is used as a magnetic pole there. Since the winding coil is wound by crossing, the distance between the coil winding portions can be reduced, and the magnetic pole can be close to the recording medium, thereby generating a sufficient magnetic field intensity and a uniform magnetic field. it can. Further, by configuring the magnetic field generating element with a combination of a high magnetic permeability and low loss magnetic material and a non-magnetic material, a magnetic field generating mechanism with higher efficiency and capable of high-frequency driving can be configured.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, and FIG.
(C) is a perspective view showing an example of a manufacturing procedure of the magnetic field generating element in the above embodiment, FIG. 3 is a schematic configuration diagram of a magneto-optical recording apparatus using the above element, and FIG. 4 is a perspective view of another embodiment. FIGS. 5 (a) to 5 (d) are perspective views showing an example of a manufacturing procedure of the magnetic field generating element, FIGS. 6 and 7 are schematic diagrams showing the configuration of a conventional example, and FIG. FIGS. 9 and 10 are schematic structural views showing still another conventional example of a conventional magnetic field generating element. DESCRIPTION OF SYMBOLS 1 ... Block 2 ... Conductor coil 3, 4 ... Coil winding part (convex part) 5 ... Recording medium 6 ... Laser emission / light receiving element

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Fujihiro Ito 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yutaka Kusano 3-30-2 Shimomaruko, Ota-ku, Tokyo (56) References JP-A-2-137150 (JP, A) JP-A-2-50829 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G11B 11 / 10 G11B 5/02

Claims (2)

(57) [Claims] 1. A method for irradiating a magneto-optical recording medium with light from a semiconductor laser and generating a magnetic field from a magnetic field generating element having a plurality of magnetic field generating sections from the opposite side to record and erase information. In the magnetic field generating mechanism of the magneto-optical recording device, the magnetic field generating element is made of a block of a high magnetic permeability and low loss magnetic material, and a coil winding portion protruding on both sides in a magnetic field generating direction corresponding to each magnetic field generating portion is formed in the block. A magnetic field generating mechanism for a magneto-optical recording apparatus, wherein the coil winding portion is a magnetic pole and the winding coil is wound with a cross over the magnetic pole. 2. A method for irradiating light from a semiconductor laser onto a magneto-optical recording medium and generating a magnetic field from a magnetic field generating element having a plurality of magnetic field generating sections from the opposite side to record and erase information. In the magnetic field generating mechanism of the magneto-optical recording device, the magnetic field generating element is composed of blocks formed by alternately arranging high magnetic permeability and low loss magnetic materials and non-magnetic materials, and corresponds to each magnetic field generating portion on both sides in the magnetic field generating direction. A magneto-optical device comprising: a coil winding portion protruding from the high-permeability low-loss magnetic material portion of the block; and the coil winding portion being wound around the coil winding portion as a magnetic pole. Magnetic field generation mechanism of recording device