WO2005001826A1

WO2005001826A1 - Magnetic field generator, magnetooptical information storing system, and magnetooptical information storage device

Info

Publication number: WO2005001826A1
Application number: PCT/JP2003/008140
Authority: WO
Inventors: Tsuyoshi Matsumoto
Original assignee: Fujitsu Limited
Priority date: 2003-06-26
Filing date: 2003-06-26
Publication date: 2005-01-06

Abstract

A magnetic field generator for generating a magnetic field, a magnetoopical information storage device for recording information onto and reproducing it from a magnetooptical storage medium that at least records information upon the application of light or magnetic field, and a magnetooptical information storage system that integrates a plurality of magnetoopical information storage devices. The generator comprises a first conductor (4413) that makes almost one round of and along a specified shape having a laterally symmetrical inner edge (4413a), a second conductor (4415) that spirally extends around the outer side of the first conductor (4413) in the same plane as that the first conductor (4413) makes a round and in the same direction as that the first conductor (4413) makes a round, and a third conductor (4416) that connects to the extending-direction end of the first conductor (4413) and to the extending-direction start of the second conductor (4415).

Description

Description Magnetic field generator, magneto-optical information storage system, and magneto-optical information storage device

The present invention provides a magnetic field generator that generates a magnetic field, a magneto-optical information storage device that records and reproduces information on a magneto-optical storage medium on which information is recorded at least by receiving light irradiation and application of a magnetic field, and The present invention relates to a magneto-optical information storage system obtained by integrating a plurality of magneto-optical information storage devices. Background art

Conventionally, information recording media such as CD, CD-ROM, CD-R, DVD, PD, M〇, and MD have been widely used as large-capacity recording media for storing audio signals and image signals. . In particular, magneto-optical storage media on which information is recorded at least by receiving light irradiation and application of a magnetic field are attracting attention as high-density recording media on which information can be rewritten. R & D is being actively conducted. In addition, research and development of a magneto-optical information storage device for performing high-speed information reproduction and information storage on such a magneto-optical recording medium have been actively performed. An optical modulation method of recording information on a recording medium by optical modulation is employed. However, with the increase in recording density as described above, information is recorded by magnetic field modulation according to information instead of the conventional optical modulation method. There has been a tendency to employ a magnetic field modulation method (see, for example, Patent Documents 1 to 5). In the magneto-optical information storage device using the magnetic field modulation method, the temperature of the recording film of the recording medium was brought close to one point by condensing a laser beam for recording, and in that state, the temperature was generated by a coil. By applying a magnetic field to the recording film, information is recorded with the magnetization direction of the recording film oriented in a direction corresponding to the information.

In a magneto-optical information storage device using such a magnetic field modulation method, in order to execute high-speed recording and reproduction of large-capacity data, an optical system for condensing light on a recording medium and a magnetic field are generated. It is desirable to have a front illumination type configuration in which the coils to be generated are arranged on the same side as viewed from the recording medium. In this configuration, an optical system is arranged on one surface of the glass substrate, and a spiral is arranged on the other surface. It is common to arrange a magnetic coil in the shape of a circle. In order to perform high-speed recording and reproduction by the magnetic field modulation method, it is necessary to switch the direction of the magnetic field applied to the recording film at a high frequency. With the above configuration, it is possible to reduce the power consumption and to reduce the inductance. A magnetic field coil becomes possible, and a magnetic field coil that can be driven at high speed can be realized.

FIG. 1 is a schematic diagram showing the structure of a general magnetic field generator of the front illumination type.

In the magnetic field generator 7 shown in FIG. 1, an optical lens 72 is disposed on an upper surface of a glass substrate 71, and a dielectric layer 73 is provided on a lower surface opposite to the upper surface. A lens 8 for focusing the laser light L toward the optical lens 72 is provided on the magnetic field generator 7, and the laser light L focused by the lens 8 is applied to a glass substrate 7 1 The light is further stopped down by an optical lens 72 provided on the upper surface of the magnetic recording medium 9, passes through the glass substrate 71 and the dielectric layer 73, and irradiates the recording layer 91 of the magnetic recording medium 9. A coil is disposed in the dielectric layer 73. This coil is spirally wound in the direction in which the dielectric layer 73 spreads so as to surround the area where the laser light L is transmitted.

FIG. 2 is a diagram of the coil included in the magnetic field generator shown in FIG. 1 when viewed from the optical lens side.

The coil 74 shown in FIG. 2 has a shape in which the diameter increases gradually from the inner peripheral end 7401 to the outer peripheral end 7402. The spot diameter of the laser beam when passing through the coil 74 is equivalent to the diameter of a circle C1 shown by a solid line. However, in this coil 74, there is a margin for alignment and the like during assembly of the magnetic field generator. In consideration of this, an area larger than the circle C1 having a diameter corresponding to the spot diameter of the laser light is secured as a transmission area through which the laser light can pass. That is, an area of a circle C2 indicated by a dotted line obtained by adding a width M as a margin to a circle C1 having a diameter corresponding to the diameter of the laser beam is secured as a transmission area.

By the way, this coil 74 has a diameter from the inner peripheral end 7401 toward the outer peripheral end 7402. The shape of the area surrounded by the innermost circle does not become circular, but is hatched to the shape of the circle C2, which is a transmission area, as shown in Fig. 2. The shape is obtained by adding the shape of the region S indicated by. In other words, in the coil 74 shown in FIG. 2, the region through which the laser light can pass is too large, and the coil 74 is larger by the extra region S. It is preferable that the diameter of the coil is as small as possible in order to increase the magnetic field generation efficiency.In the coil 74 shown in FIG. 2, the loss in the magnetic field generation efficiency is reduced by the area S indicated by hatching. Will be.

Also, when assembling the magnetic field generator, when disposing the optical lens 72 on the upper surface of the glass substrate 71 on which the coil is formed as shown in FIG. 1, the positioning of the optical lens 72 is performed by positioning the optical lens 72. This is done by aligning the optical axis with the center of the coil. However, in the case of the coil 74 shown in FIG. 2, it is difficult to determine the center of the coil, resulting in poor workability.

Next, a conventional magnetic field generator different from the magnetic field generator shown in FIG. 1 will be described with reference to FIG. Here, the same components as those described so far will be described using the same reference numerals as those used so far.

FIG. 3 is a diagram showing a part of a magnetic field generator in which coils wound in a spiral shape are provided in upper and lower layers.

The magnetic field generator 7 shown in FIG. 3 has two layers of coils 741 and 742 disposed in a dielectric layer 73. Each of these coils 741 and 742 spirals in a direction in which the dielectric layer 73 spreads so as to surround a region through which the laser beam passes. Each of these coils 741 and 742 has a shape whose diameter gradually increases from the inner peripheral end toward the outer peripheral end, and is represented by a dotted line obtained by adding the width M as a margin to the spot diameter of the laser beam L. The region indicated by is secured as a transmission region through which the laser light can pass. In FIG. 3, the spot diameter of the upper layer (hereinafter, referred to as the second layer) is smaller than that of the lower layer (hereinafter, referred to as the first layer) in FIG. The coil 742 provided in the layer has a smaller transmission area than the coil 741 provided in the first layer.

FIG. 4 is a diagram when the coil of the magnetic field generator shown in FIG. 3 is viewed from the optical lens side. The two coils 741 and 42 shown in FIG. 4 are connected to each other at their inner ends 7411 and 7412, forming one conductor. Even when assembling the magnetic field generator 7 shown in FIG. 3, it is necessary to align the optical axis of the optical lens 72 with the center of the coil when positioning the optical lens, but in the magnetic field generator 7 shown in FIG. Since the sizes of the transmission areas of the coils 741, 742 provided in the upper and lower two layers are different from each other, the center of each coil 741, 742 is more difficult to determine than the coil shown in FIG. Significantly lower workability.

By the way, a protective film is provided on the surface of the coil to protect the coil from corrosion and collision with other objects. In addition, the transmission area secured in the center of the coil needs to be optically uniform and transparent.

FIG. 5 is a schematic diagram showing, in an enlarged manner, a portion of a conventional front-illumination type magnetic field generator provided with coils.

Here, the same components as those described so far will be described using the same reference numerals as those used up to now.

Generally, resin materials have a birefringence and are optically non-uniform. For this reason, some magnetic field generators in which the dielectric layer 73 covering the coil is made of a resin material do not cover the transmission region through which the laser light is transmitted. In the magnetic field generator 7 shown in FIG. 5, a projection 711 made of a glass material is provided integrally with a glass substrate 71, and a dielectric layer 7 made of a resin material is provided around the projection 711. Three are provided. In the dielectric layer 73, there is provided a coil 74 that spirals around the projection 711, and the transmission area of the laser light L is formed by the projection 7111 made of a glass material. I am trying to become. The coil 74 must be completely covered with the dielectric layer 73, and therefore, in the magnetic field generator 7 shown in FIG. 5, the coil 74 is located inside the innermost circumferential portion 7400 of the coil 74. The diameter of the innermost circumferential portion 7403 of the coil is larger than the diameter of the protrusion 711 by the amount of the dielectric layer 73 interposed (Fig. 5). (See r in the figure.) The problem is that the efficiency of magnetic field generation decreases.

Figure 6 shows an enlarged view of the portion of a conventional magnetic field generator in which a dielectric material is provided by vacuum evaporation to provide uniform optical characteristics of the protective film covering the coil, in which the coil is provided. FIG.

In the magnetic field generator 7 shown in FIG. 6, the optically uniform dielectric layer 73 is formed by vacuum evaporation, so that unlike the magnetic field generator shown in FIG. 5, the projections 7 11 made of a glass material are unnecessary. The dielectric layer 73 extends over the entire surface of the glass substrate 71 on which the coil 74 is provided, and the dielectric layer 73 extends to the laser light L transmission region. By doing so, the problem caused by the magnetic field generator shown in FIG. 5 is solved, and the diameter of the innermost circumferential portion 7403 of the coil can be reduced.

By the way, as shown in FIG. 3, when the coils are provided in the upper and lower two layers, first, the coil 71 of the first layer is formed, and then the dielectric is vacuumed on the surface of the coil 741 of the first layer. After being formed by vapor deposition and covering the first layer coil 741 with a dielectric material, the second layer coil 742 is formed on the dielectric layer. In forming the second layer coil 742, first, in order to make the surface of the dielectric layer covering the first layer coil 741 flat, the surface of the dielectric layer is polished. A second layer coil 7 42 is formed. FIG. 7 is a diagram showing a state before polishing the surface of the dielectric layer formed by vacuum deposition, and FIG. 8 is a diagram showing a state after polishing the surface of the dielectric layer shown in FIG. It is.

In FIG. 7, the dielectric material P is not sufficiently filled between the radially adjacent circumferential portions 7404 of the coil 74, so that a gap g is generated. This gap g extends to a position higher than the surface of the coil 74, and by polishing, the gap g appears on the surface 731a of the dielectric layer 731 as shown in FIG. The opening gl has occurred. If post-processes such as forming a coil of the second layer are performed on the surface 731a of the dielectric layer where the opening g1 is formed, foreign matter enters through the opening g1 to cause a product defect, Alternatively, the opening g1 adversely affects the formation of the coil pattern of the second layer. In order to prevent a void from being formed between the radially adjacent circling portions of the coil 74, it is sufficient to make it easier for the dielectric material to enter between the adjacent circling portions. In the magnetic field generator 7 shown in FIG. 6, the interval w between the adjacent orbiting portions is set to about twice the thickness h of the coil 74. However, the distance w between adjacent orbiting parts can be increased. The larger the coil, the larger the diameter of the coil as it gets closer to the outer periphery, and the lower the efficiency of magnetic field generation.

Also, as one of the techniques for reducing the diameter of the coil, a technique for forming a thin dielectric film on the coil has been proposed (for example, see Patent Document 6).

FIG. 9 is a diagram showing a coil on which a thin dielectric film is formed, and FIG. 10 is an enlarged view of a region surrounded by a chain line in FIG.

FIG. 9 shows upper and lower two-layer coils 741, 742. In order to form the upper and lower two-layer coils 741 and 742 shown in FIG. 9, first, the first-layer coil 741 is formed, and then a thin dielectric is formed so as to cover the coil 741. A film 732 is formed. Next, a coil pattern of the second layer coil 742 is formed between the radially adjacent circulating portions 7414 of the coil 741. The upper and lower two-layer coils 741 and 742 obtained in this way are placed in the hollow b between the radially adjacent circulating portions 7414 of the first-layer coil 741, and a thin dielectric The radially adjacent portion 7 4 2 4 of the coil 7 42 of the second layer via the body membrane 7 32 is located, and the coil 7 4 1 of the first layer 7 Even if it is 42, the diameter can be small. However, as shown in FIG. 10, the corners of the depression b of the thin dielectric film 732 become the weakened portions 7321, and the first layer coil 741 and the second layer coil 7 There is a problem that the insulation between the two is easily broken.

Furthermore, the coil 74 is not limited to the coils 741, 742 shown in FIG. 9, and when the coil 74 is energized, the coil 74 generates heat. In general, the electrical resistance of a material increases with increasing temperature. For this reason, if the heat generated in the coil 74 is not efficiently radiated, the coil 74 enters a vicious circle in which its own heat consumption increases its power consumption and further increases its calorific value. Although the coil 74 of the magnetic field generator 7 described in FIG. 5 is covered with a resin material, since the thermal conductivity of the resin material is not so good, the heat generated by the coil 74 is hardly radiated, and The temperature of 74 may rise at an accelerating rate, and the coil 74 may be broken before generating a magnetic field of a predetermined strength. In addition, the resin material can be thermally sensitive and can provide the required magnetic field. There is also a problem that it is difficult to flow a current for the purpose.

(Patent Document 1)

JP 2002-203302 A

(Patent Document 2)

JP-A-63-259814

(Patent Document 3) ''

JP-A-3-276410

(Patent Document 4)

Japanese Patent Application Laid-Open No. 5-242430

(Patent Document 5)

JP-A-7-302409

(Patent Document 6)

JP 2001-185419A DISCLOSURE OF THE INVENTION

In view of the above circumstances, the present invention provides a magnetic field generator that efficiently generates a magnetic field, a magneto-optical storage device including the magnetic field generator, and a magneto-optical information storage system including a plurality of the magneto-optical storage devices. The purpose is to do.

A first magnetic field generator according to the present invention that achieves the above object has a first conductor whose inner edge is substantially circumscribed along a predetermined shape that is bilaterally symmetric,

A second conductor spirally circling the outside of the first conductor in the same direction as the circling direction of the first conductor in the same plane as the plane on which the first conductor circulates;

A third conductor that connects a circumferential end of the first conductor and a circumferential start of the second conductor.

According to the first magnetic field generator of the present invention, since the inner peripheral shape defined by the first conductor is a symmetrical shape, it does not include an extra area S as shown in FIG. The diameter of the coil composed of the second conductor and the third conductor is reduced, and a magnetic field can be generated efficiently. In addition, as the diameter of the coil decreases, the inductance of the coil also decreases, and the driving frequency of the magnetic field generator increases. be able to. Further, since the inner peripheral shape determined by the first conductor is a symmetrical shape, the center of the first conductor can be easily determined.

Further, in the first magnetic field generator of the present invention, the first conductor has a predetermined width portion which is circulated from a start end in a circling direction of the first conductor with an inner edge and an outer edge kept at equal intervals, and an outer edge is formed on the inner edge. It is preferable that the widened portion is formed so as to gradually extend outward and extend from the end of the predetermined width portion in the circumferential direction to the end of the first conductor in the circumferential direction.

In this embodiment, the first conductors are connected by a smooth curve, and the periphery of the first conductors can be easily filled with an insulator or the like, which facilitates manufacturing.

Further, in the first magnetic field generator of the present invention, the second conductor has a first circling portion circling at an equal interval with the predetermined width portion, and circling at an equal interval with an outer edge of the widening portion. It is also preferable that the second circling portion is alternately provided.

By doing so, the diameter of the second conductor is minimized, a magnetic field can be generated more efficiently, and the driving frequency of the magnetic field generator can be further increased.

A second magnetic field generator of the present invention that achieves the above object is a dielectric layer made of alumina,

A conductor spirally circulating in the same plane inside the dielectric layer, wherein the conductor has a constant interval between adjacent radiating portions in the radial direction, and the interval is equal to the thickness of the conductor. It is characterized by being 0.4 times or more and 0.8 times or less. In the second magnetic field generator of the present invention, even if a gap is formed between the orbital portions adjacent in the radial direction, the gap remains closed as long as the tip of the created gap is prevented from appearing on the surface. It was found that there was no problem in this state, and the gap was narrowed to prevent the tip of the void from appearing on the surface. Here, if the interval is less than 0.4 times the thickness of the conductor, the alumina does not enter between the adjacent circulating portions too much, and a problem occurs in insulation between the adjacent circulating portions. On the other hand, if it exceeds 0.8 times, the tip of the void tends to appear on the surface. As described above, according to the second magnetic field generator of the present invention, since the interval between the orbital portions is narrowed, the diameter of the conductor is reduced, and a magnetic field can be generated efficiently. In addition, as the diameter of the conductor decreases, the inductance of the conductor also decreases. Can be increased. In addition, since the dielectric layer is made of alumina, the heat dissipation is higher than that of the dielectric layer made of a resin material. In this respect, it is larger than that of the magnetic field generator having the dielectric layer made of the resin material. A magnetic field can be generated, and the optical properties of the dielectric layer can be uniform. In the second magnetic field generator of the present invention, the conductor has an edge extending in a circumferential direction with a chamfer. It is preferred that it is done.

In the second magnetic field generator of the present invention, since the interval between the orbital portions is narrowed, it is difficult to insert alumina between the orbital portions, but this makes it easier to insert alumina.

Further, in the second magnetic field generator of the present invention, the dielectric layer is provided on a glass substrate surface,

It is also preferable that the magnetic field generator has an aspect in which an adhesion film for increasing the adhesion between the conductor and the dielectric layer is provided on the surface of the conductor opposite to the glass substrate. There is a difference between the coefficient of thermal expansion of the conductor and the coefficient of thermal expansion of alumina. When the conductor is energized, the conductor generates heat and the temperature rises. Cracks may occur, and the alumina covering the orbital portion may come off. This crack is more likely to occur because the narrower the space between the orbital portions, the thinner the alumina between them. In this aspect, even if cracks occur, the adhesive film can prevent the alumina in the orbital portion from peeling off.

Further, in the second magnetic field generator of the present invention, the conductor is inclined such that an outer edge thereof is separated from a second peripheral circuit part radially adjacent to the innermost peripheral part of the innermost periphery. It has an end connected to the inner circumference part,

The diameter of the magnetic field generator is calculated from the midpoint at the boundary between the innermost circumference part and the end part, which divides the distance between the innermost circumference part and the second circumference part into two equal parts. Let L be the distance to the center of a circle that is 1.5 times the thickness of the body and touches both the outer edge of its end and the inner edge of its second orbital, and The relationship 2 X d> L holds when the distance from to the conductor surface is d. It is also preferable.

This makes it easier for alumina to be packed between the end portion and the second orbital portion, thereby more reliably preventing the appearance of voids. '

A first magneto-optical information storage system according to the present invention, which achieves the above object, is a disk-shaped optical disk capable of recording and reproducing information, and at least performing information recording by receiving light irradiation and application of a magnetic field. A medium storage unit in which a plurality of magnetic storage media are stored; a recording / reproducing unit for recording and / or reproducing information on / from the magneto-optical storage medium; A plurality of magneto-optical information storage devices each including a medium moving unit that moves a magnetic storage medium, and a blade housing that integrally holds the medium storage unit, the medium moving unit, and the recording / reproducing unit; A system housing on which the plurality of magneto-optical information storage devices are mounted and which detachably holds the plurality of magneto-optical information storage devices;

A control unit that controls recording and / or reproduction of information in each of the plurality of magneto-optical information storage devices mounted on the system housing,

The recording / reproducing unit is

A first conductor whose inner edge is substantially circumnavigated along a predetermined shape that is symmetrical left and right, and the outside of the first conductor is defined as the circling direction of the first conductor in the same plane as the plane on which the first conductor circulates. A magnetic field generator having a second conductor spirally wound in the same direction, and a third conductor connecting a circumferential end of the first conductor to a circumferential start of the second conductor;

With a light source that emits light,

By applying a magnetic field generated by the magnetic field generator to the magneto-optical storage medium and irradiating light emitted from the light source, information is recorded on the magneto-optical storage medium. I do.

A second magneto-optical information storage system according to the present invention, which achieves the above object, has a disk-shaped optical system capable of recording and reproducing information, and at least performing information recording by receiving light irradiation and application of a magnetic field. A medium storage unit in which a plurality of magnetic storage media are stored; a recording / reproducing unit for recording and / or reproducing information on / from the magneto-optical storage medium; and a light source between the medium storage unit and the recording / reproducing unit. Medium for moving magnetic storage medium A plurality of magneto-optical information storage devices each including a moving unit, a blade housing that integrally holds the medium storing unit, the medium moving unit, and the recording / reproducing unit; and the plurality of magneto-optical information storages. A system housing on which the device is mounted and which detachably holds the plurality of magneto-optical information storage devices;

The recording / reproducing unit is

A dielectric layer made of alumina, and a conductor spirally wrapped in the same plane inside the dielectric layer, wherein the conductor has a constant distance between adjacent radiating portions in the radial direction, A magnetic field generator whose spacing is at least 0.4 times and at most 0.8 times the thickness of the conductor;

With a light source that emits light,

The first magneto-optical information storage device of the present invention that achieves the above object has a disk-shaped magneto-optical device capable of recording and reproducing information, and at least performing information recording by receiving light irradiation and application of a magnetic field. A magneto-optical information storage device for recording and / or reproducing information to and from a storage medium,

A medium storage unit in which a plurality of the magneto-optical storage media are stored,

A recording / reproducing unit that records and / or reproduces information on the magneto-optical storage medium; a medium moving unit that moves the magneto-optical storage medium between the medium storage unit and the recording / reproducing unit;

A blade housing in which the medium storage unit, the medium moving unit, and the recording / reproducing unit are arranged in a line, and the medium housing unit, the medium moving unit, and the recording / reproducing unit are integrally held;

A system housing in which a plurality of the information storage devices are mounted, a connection unit for detachably connecting the information storage device,

The recording / playback unit, A first conductor whose inner edge is substantially circumnavigated along a predetermined shape that is symmetrical left and right, and in the same plane as the plane around which the first conductor circulates, the outside of the first conductor is defined as the circling direction of the first conductor. A magnetic field generator having a second conductor spirally wound in the same direction, and a third conductor connecting a circumferential end of the first conductor to a circumferential start of the second conductor;

With a light source that emits light,

A second magneto-optical information storage device of the present invention that achieves the above object is a disk-shaped magneto-optical device capable of recording and reproducing information, and at least recording information by receiving light irradiation and application of a magnetic field. A magneto-optical information storage device for recording and / or reproducing information on and from a storage medium,

The recording / reproducing unit is

With a light source that emits light,

When a magnetic field generated by the magnetic field generator is applied to the magneto-optical storage medium, Both are characterized in that information is recorded on the magneto-optical storage medium by irradiating the light emitted from the light source.

It is to be noted that, for each of the magneto-optical information storage system and the magneto-optical information storage device according to the present invention, only the basic form is shown here, but this is simply to avoid duplication. The magneto-optical information storage system and the magneto-optical information storage device described above include not only the above-described basic mode but also various modes corresponding to the above-described modes of the magnetic field generator.

As described above, according to the present invention, a magnetic field generator that efficiently generates a magnetic field, a magneto-optical storage device including the magnetic field generator, and a magneto-optical information storage system including a plurality of the magneto-optical storage devices Can be provided. Brief Description of Drawings

FIG. 4 is a diagram when the coil of the magnetic field generator shown in FIG. 3 is viewed from the optical lens side.

Fig. 6 is a schematic diagram showing an enlarged view of the part where a coil is installed in a conventional magnetic field generator where a dielectric material is installed by vacuum evaporation to make the optical characteristics of the protective film covering the coil uniform. FIG.

FIG. 7 is a diagram showing a state before polishing the surface of the dielectric layer formed by vacuum deposition.

FIG. 8 is a diagram showing a state after the surface of the dielectric layer shown in FIG. 7 has been polished. FIG. 9 is a diagram showing a coil on which a thin dielectric film is formed. FIG. 10 is an enlarged view of a range surrounded by a chain line in FIG.

FIG. 11 is an external view showing each embodiment of the optical information storage system and the optical information storage device of the present invention.

FIG. 12 is a diagram showing details of the magazine.

FIG. 13 is a diagram illustrating a hardware structure of the blade device.

FIG. 14 · is a functional block diagram illustrating a functional structure of the blade device.

FIG. 15 is a diagram showing the structure near the head of the drive.

FIG. 16 is a diagram showing a part of the magnetic field generator shown in FIG.

FIG. 17 is a diagram showing a state of the finishing processing of the first coil.

FIG. 18 is a view showing a state before polishing the surface of the alumina layer formed by vacuum evaporation.

FIG. 19 is a view showing a state after polishing the surface of the alumina layer shown in FIG. 18. FIG. 20 is a view showing cracks generated between the orbital portions.

FIG. 21 is a diagram showing a coil in which a measure has been taken to prevent the alumina between adjacent orbiting portions from peeling off.

FIG. 22 is a diagram of the coil of the magnetic field generator shown in FIG. 16 when viewed from the optical lens side.

FIG. 23 is a diagram illustrating the first coil when viewed from the optical lens side.

FIG. 24 is a diagram showing how the coil and the optical lens are aligned.

FIG. 25 is an enlarged view of the inner peripheral end portion of the first coil shown in FIG. 23 from the optical lens side.

FIG. 26 is a diagram when the inner peripheral end portion of the first coil shown in FIG. 23 is sectioned in the direction in which the coil rotates.

FIG. 27 is a diagram illustrating a coil whose inner peripheral shape is elliptical.

FIG. 28 is a diagram showing a coil whose inner peripheral shape is an ellipse. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described. In the following explanation, "information" And "data" are sometimes used without distinction.

FIG. 11 shows a blade device 10 corresponding to one embodiment of the optical information storage device of the present invention using a magneto-optical (MO) disk as an example of the optical storage medium of the present invention, An aggregate system 20 corresponding to one embodiment of the optical information storage system of the present invention, in which 10 blade devices 10 are incorporated in the figure, is shown. The housing 11 of the blade unit 10 has a length that is more than three times the diameter of the MO disk, a width slightly larger than the diameter of the M0 disk (height in this figure), and a greater diameter than the diameter of the MO disk. In this case, a magazine 12 containing a plurality of MO disks is removably arranged at one end of the housing 11.

A plurality of blade devices 10 are mounted in the housing 21 of the collective system 20 so that they can be freely inserted and removed.The magazine 12 of each blade device 10 is equipped with the blade device 10 in the housing of the integrated system 20. It is detachable even when inserted into the body 21. In addition, the collective system 20 is also provided with a control device 22 that controls recording and reproduction of information in each of the plurality of blade devices 10.

Such a collective system 20 is a compact and large-capacity storage system in which a plurality of blade devices 10 are compactly housed in a housing 21. In addition, the capacity can be easily expanded by increasing the number of M〇 disks and blade devices 10, and maintenance can be easily performed by attaching / detaching or replacing the magazine 12 or the blade device 10.

FIG. 12 is a diagram showing details of the magazine.

In part (A) of FIG. 12, a perspective view showing a state in which a plurality of MO disks 13 are stored in the magazine 12 is shown, and the area P 2 surrounded by a chain line is enlarged. A cross-sectional view is shown in part (B) of FIG.

A removable FRAM 14 is inserted into the magazine 12, and the terminal 14 a of the FRAM 14 contacts an internal terminal 12 a provided in the magazine 12, and the internal It is electrically connected to the external terminal 12b connected to the terminal 12a. This outside The terminal 1 2b is electrically connected to the internal wiring of the blade device 10 when the magazine 12 is mounted on the blade device 10 shown in FIG. I4 can be read and written.

The storage location of each MO disk 13 in the magazine 12 is recorded in the FRAM 14.

In the present embodiment, a MO disk 13 of a type capable of recording information on both front and back surfaces is used, and a recording film is provided on both front and back surfaces of the MO disk 13. Irradiation of light and application of a magnetic field are performed on the recording film on each of the front and back surfaces, as will be described in detail later, and information is recorded and reproduced. Each blade device 10 shown in FIG. 11 has a structure capable of simultaneously accessing the front and back of the MO disk 13. FIG. 13 is a diagram showing a hardware structure of the blade device.

The blade device 10 also shown in FIG. 11 includes the above-mentioned magazine 12 and a drive 16 for recording and reproducing information on and from the M〇 disk 13 in a housing 11. A changer 15 for moving the MO disk 13 between them is provided between the magazine 12 and the drive 16. The drive 16 corresponds to an example of a recording / reproducing unit according to the present invention, and the changer 15 corresponds to an example of a medium moving unit according to the present invention.

As described above, the blade device 10 is a compact device in which the magazine 12, the changer 15, and the drive 16 are housed in the housing 11. The storage capacity can be easily expanded by increasing the number of disks 13. In addition, maintenance can be easily performed by attaching and detaching and replacing the magazine 12 and the MO disk 13.

One end of the blade device 10 opposite to the magazine 12 is provided with an interface connector 17a for transferring data between the blade device 10 and the outside. When the connector 17a is inserted into the housing 21 of the collective system 20 shown in FIG. 1, the connector 17a is joined to the connector of the collective system 20. This connector 17a corresponds to an example of the connecting portion according to the present invention.

Changer 15 is a machine that inserts and removes MO disk 13 from magazine 12 It has a function to move the MO disk 13 up and down in the figure, and a function to set the M〇 disk 13 into and out of the drive 16. As described with reference to FIG. 11, the housing 11 in the present embodiment has a length that is three times or more the length of the M〇 disk 13, but the changer 15 and the drive 16 are The M〇 disk 13 on 5 and the MO disk 13 loaded in the drive 16 can be arranged in a positional relationship such that they overlap each other.The length of the blade housing according to the present invention is: It is preferable that the diameter is at least 2.5 times the diameter of the optical storage medium. FIG. 14 is a functional block diagram showing the functional structure of the blade device.

As described above, the blade device 10 includes the magazine 12, the changer 15, and the drive 16, and further includes a control unit 18 that controls the changer 15 and the drive 16, and the blade device 1. There is also an interface 17 for data transfer between 0 and the outside world. This interface 17 is selected from well-known high-speed serial interfaces such as IEEE 1394, USB, and serial ATA, and the detailed description is omitted. I do.

The drive 16 is equipped with a spindle motor 16 1 that holds and rotates the MO disk, and a head 16 2 that irradiates light to the M〇 disk to record and reproduce information. Two heads 16 2 are provided for the first side and the second side (front and back) of the MO disk, respectively. Drive 16 also has read / write channels 163 for the first and second sides, respectively, and a first-in first-out (FIFO) memory 1664 that acts as a buffer. I have.

To the control unit 18, designation information for designating an MO disk is input from outside the device via a path (not shown) via the interface 17. When the designated information is input, the control unit 18 finds the designated MO disk from among a plurality of M〇 disks stored in the magazine 12 based on the designated information, and changes the changer 15 Is instructed to set the found M〇 disk from magazine 12 to drive 16. The changer 15 takes out the M〇 disk specified by the control unit 18 from the magazine 12 and sets it in the drive 16. In other words, the control unit 18 determines the M〇 disk to be accessed based on the stored information Since it is possible to find a disk, it is possible to quickly start access even when, for example, the magazine 12 is exchanged.

The blade device 10 is provided with an access path 19 for directly accessing the FRAM 14 from the outside of the blade device 10 bypassing the control unit 18. Even when the power is turned off, the stored information of FRAM 14 can be externally confirmed through this access path 19.

FIG. 15 is a diagram showing the structure near the head of the drive.

The drive 16 is provided with two heads 16 2, and FIG. 15 shows a structure near the two heads 16 2. These two heads 16 2 are arranged with a MO disk 13 held and rotated by a spindle motor 16 1 interposed therebetween, and each head 16 2 is fixed to a drive base (not shown). Fixed assembly 32 and a movable assembly (carriage) 31 that can move in the radial direction of the MO disk.

The fixed assembly 32 includes a laser diode 321, which is an example of a light source according to the present invention, which generates a laser beam used for reading and writing information, and light reflected by the MO disk 13 In addition to a built-in photodetector 322 that detects a signal corresponding to information stored in the MO disk 13, various optical elements are also built in.

The moving assembly 31 1 moves in the radial direction of the MO disk 13, irradiates a laser beam to a desired position on the MO disk 13, applies a magnetic field, and is further reflected by the MO disk 13. It has the function of returning light to the fixed assembly 32. The moving assembly 31 includes a carriage base 33, a rising mirror 34 for reflecting laser light, a magnetic field generator 40 having a coil, and a laser beam focused toward the magnetic field generator 40. It has a condenser lens 35 and a lens actuator 36 that moves the condenser lens 35.

The magnetic field generator 40 shown in FIG. 16 has a glass substrate 41 provided with an optical lens (not shown) on one surface. The surface of the glass substrate 41 opposite to the surface on which the optical lens is provided is a flat surface, and the dielectric layer 43 is formed on the flat surface. The In the magnetic field generator 40, the optical lens faces the condenser lens 35 shown in FIG. 15 and the dielectric layer 43 faces the MO disk 13 set in the drive 16 shown in FIG. So the moving assembly is deployed in 31. The laser beam L narrowed down by the condenser lens 35 is further narrowed down by the optical lens provided on the glass substrate 41, passes through the glass substrate 41 and the dielectric layer 43, and is Irradiated on 13.

The dielectric layer 43 shown in FIG. 16 is made of alumina having relatively high thermal conductivity, and its thermal conductivity is about 2 OW / mK. Inside this dielectric layer 43, two layers of coils 441 and 442 are provided. Each of these coils 4 41 and 4 42 is spirally wound so as to surround a region through which the laser light L passes. Here, a coil spirally wound in the same plane on the side of the glass substrate 41 is referred to as a first coil 441, and the same coil that is further away from the glass substrate 41 than the first coil 441. The coil that spirals around inside is referred to as a second coil 442. In the magnetic field generator 40 shown in FIG. 16, the coils 44 1 and 44 2 are covered with alumina having a higher thermal conductivity than a general resin material, so that the coils 4 4 1 and 4 4 2 The heat generated by the coil is easily dissipated, preventing damage to the coil and making it easy to pass current to obtain the required magnetic field. ·

In each of these coils 4 41 and 4 42, the area indicated by the dotted line obtained by adding the width M as a margin to the spot diameter of the laser beam L (see the solid line SP) is the laser beam L. Is secured as a transmissive area through which the light can pass. Alumina exists in the transmission region, and the alumina, that is, the dielectric layer 43 is formed by vacuum evaporation. The optical properties of alumina formed by vacuum evaporation are uniform, and therefore, uniform optical properties are guaranteed even in the transmission region. Unlike the magnetic field generator 7 shown in FIG. 1 1 becomes unnecessary. As a result, in the magnetic field generator 40 shown in FIG. 16, the innermost circumference of the coil 4 4 1 3, 4 4 2 3 is larger than the coil 74 provided in the magnetic field generator 7 shown in FIG. 5. Can be made smaller, and a magnetic field can be generated efficiently.

In forming the first coil 4 41 and the second coil 4 42 shown in FIG. 16, First, after forming the first coil 441, an alumina layer made of alumina is formed on the surface of the first coil 441 by vacuum evaporation, and the first coil 441 is covered with alumina. The surface of the layer is flattened by polishing, and then the second coil 442 is formed.

First, the formation of the first coil 441 will be described with reference to FIG.

In forming the conductor portion 4 4 18 of the coil, an electrolytic plating method is used. A region other than the coil portion is covered with a resist on a glass substrate 41 on which a thin electrode film has been formed in advance. The cross section of the resist is formed in a rectangular shape by the photolithography technique at this time. By performing the electroplating in this state, a conductor such as copper is selectively formed in a portion of the electrode film that is not covered with the resist. After the plating, the resist is removed, and the electrode film portion where the conductor is not formed by etching is removed to obtain a coil in which the conductor 4 4 18 with a rectangular cross section shown in Fig. 17 spirals around. . Next, a mask 950 shown in FIG. 17 is applied to the surface 4418a of the conductor 4418 with a resist or the like. The mask 950 is applied to the center of the conductor 418 in the width direction so as not to reach the edge 418 b extending in the circumferential direction of the conductor 418. Subsequently, using a device such as ion milling, the surface 418 a of the conductor is lightly shaved. In this way, the edge 4 4 18 b without the mask 950 is cut more than the center where the mask is applied, and extends in the circumferential direction of the conductor 4 18 緣 4 4 18 b is chamfered (See the dotted line in the figure). When the dielectric layer is formed by vacuum deposition due to the chamfering of the edges 4 4 18 b extending in the circumferential direction of the conductor 4 4 18, the alumina is used to form a conductor ( It is easy to get in between

Next, formation of the alumina layer will be described.

FIG. 18 is a diagram showing a state before polishing the surface of the alumina layer formed by vacuum evaporation, and FIG. 19 is a diagram showing a state after polishing the surface of the alumina layer shown in FIG. 18. It is.

In FIG. 18, the alumina A1 is not sufficiently filled between the radially adjacent orbiting portions 4414 of the first coil 441, so that a gap g is generated. The tip of this gap g Even if the surface of the alumina layer 431 is polished at a position lower than the surface 41a of the first coil 441, as shown in FIG. It does not appear on the polished surface 431a, and the gap g remains closed.

In the first coil 4 41 formed in this way, the interval w between the orbiting portions 4 4 1 1 adjacent in the radial direction is constant, and the interval w is 0 mm of the thickness h of the first coil 4 4 1. . Equivalent to 6 times. In a conventional magnetic field generator, the gap w between the radially adjacent circling portions is set to be as wide as possible in order to completely prevent the formation of a gap between the radially adjacent circling portions of the coil. However, in the magnetic field generator according to the present embodiment, even if a gap occurs, the gap remains closed as long as the tip of the created gap does not appear on the surface after polishing. Does not penetrate or adversely affect the pattern formation of the second coil, and by daringly narrowing the interval w, the tip of the gap g becomes the surface of the first coil 4 4 1 a It is prevented from extending to a higher position. Here, the interval w is set to 0.6 times the thickness of the coil, but is not limited to this, and may be set to 0.4 times or more and 0.8 times or less. If it is less than 0.4 times, the alumina does not enter too much between the adjacent circulating portions 4 4, and a problem occurs in insulation between the adjacent circulating portions. On the other hand, if it exceeds 0.8 times, the tip of the gap g extends to a position higher than the alumina surface 431a, and an opening occurs after polishing. The above description is for the first coil 4 41, but for the second coil 4 42, as in the case of the first coil 4 41, the interval between the circumferentially adjacent circling portions is constant, and The interval w corresponds to 0.6 times the thickness of the second coil 442. As described above, in the magnetic field generator according to the present embodiment, the diameter of the coil is reduced by narrowing the interval between the orbital portions adjacent to each other in the radial direction of the coil, so that the magnetic field is generated efficiently and The inductance is also reduced, and the driving frequency can be increased. The formation of the second coil 442 is performed in the same manner as the formation of the first coil 441.

As described above, in the magnetic field generator according to the present embodiment, the interval between the orbital portions of the coil that are adjacent in the radial direction is narrower than before. However, as the distance is reduced, cracks may occur due to the difference in the coefficient of thermal expansion.

FIG. 20 is a diagram showing cracks generated between the orbital portions. In the coil 44 'shown in FIG. 20, the distance between the orbital portions 4404' that are adjacent in the radial direction is less than 0.4 times the thickness of the coil 44 '. The smaller this spacing, the thinner the thickness of alumina between adjacent circulating portions 4404 '. When current is applied to generate a magnetic field in the coil 44 ', the coil 44' generates heat and its temperature rises. There is a difference in the coefficient of thermal expansion between the coil 44 'and alumina, and this difference in coefficient of thermal expansion causes a crack f as shown in Fig. 20 in the alumina between the adjacent orbiting parts 4404', and in the worst case In this case, the alumina covering the orbital portion 4404 'may come off and the surface 44'a of the coil may be exposed. The problem of this crack f is a problem that remains even if the distance between the circling parts adjacent in the radial direction is more than 0.4 times the thickness of the coil, and prevents the alumina in the circulating part from peeling off It is preferable to take countermeasures.

FIG. 21 is a diagram showing a coil in which measures have been taken to prevent the alumina in the orbiting portion from peeling off.

On the surface 61a of the coil 61 shown in FIG. 21, that is, on the surface on the side opposite to the glass substrate 62, an adhesion film 63 for increasing the adhesion to alumina is formed. The adhesion film 63 is, for example, a film made of chromium or titanium and having a thickness of about several hundred A. Even if a crack f occurs as shown in FIG. 20, in the magnetic field generator having the adhesion film 63 formed thereon, the alumina covering the coil 61 is tied up by the adhesion film 63 to prevent the alumina from falling off.

FIG. 22 is a diagram when the coil of the magnetic field generator shown in FIG. 16 is viewed from the optical lens side.

The first coil 441 and the second coil 442 shown in FIG. 22 are connected to each other at portions overlapping each other near the inner peripheral ends 4411 and 4421 to form one conductor. As shown in FIG. 22, the inner edges 4413a and 4423a of the innermost circumferential portions 4413 and 4423 are formed along the true circle regardless of the first coil 441 or the second coil 442. It is a round of the circle. That is, each of the inner edges 4413a and 4423a is formed by making substantially one round of the predetermined shape along the left-right symmetric predetermined shape. Therefore, each of the innermost circumferential portions 4413 and 4423 corresponds to an example of the first conductor according to the present invention. Hereinafter, the description will be focused on the first coil 4 41, but the description here is also applicable to the second coil 4 42.

The spot diameter of the laser beam when passing through the first coil 4 41 shown in FIG. 23 corresponds to the diameter of the circle C 1 shown by the solid line. In consideration of a margin for alignment and the like at the time of assembling, an area larger than a circle C1 having a diameter corresponding to the spot diameter of the laser light is secured as a laser light transmission area. That is, an area of a circle C2 indicated by a dotted line obtained by adding a margin to a circle C1 having a diameter corresponding to the diameter of the laser light is secured as a transmission area. The inner edge 4 4 13 a of the innermost peripheral portion 4 4 13 of the first coil 4 41 is formed by substantially making one round of the circle C 2 along the circle C 2 corresponding to this transmission area And its inner edge 4 4 1 3a approaches the circle C 2 to its limit. Therefore, unlike the coil 74 shown in FIG. 2, the first coil 441 shown in FIG. 23 does not include the extra area S shown in FIG. It generates a magnetic field more efficiently than 4. Also, the inductance of the conductor is reduced, the driving frequency of the magnetic field generator 40 in the present embodiment can be increased, and high-speed access to the MO disk is possible. In the first coil 441, shown in Fig. 23, the current is reduced by about 2 to 3% and the power consumption is reduced by about 4 to 6%, depending on the wire width and the number of turns of the coil. The inductance is reduced by about 10%.

Furthermore, since the inner edge 4 4 13 a of the innermost circumference 4 4 13 is substantially one round of the circle C 2 along the circle C 2, the center of the first coil 4 4 1 When the optical lens is positioned at the time of assembling the magnetic field generator shown in FIG. 16, it is easy to align the optical axis of the optical lens with the center of the first coil 441, thereby improving workability. Is improved.

FIG. 24 is a diagram showing how the coil and the optical lens are aligned.

In positioning the coil and the optical lens, a glass substrate 41 on which a coil 44 is formed is placed between the opposed microscopes 90 1 and 90 2, and an optical lens 4 2 is placed on the glass substrate 41. Put. The microscope 90 1 on the optical lens 42 side detects the position of the optical lens 42, and the microscope 90 2 on the glass substrate 41 side detects the position of the coil 44. To detect. Then, based on the detected positions, the glass substrate 41 and the optical lens 4 2 are adjusted so that the optical axis of the optical lens 42 matches the center of the coil 44 (see the dashed line in the figure). Is moved (see the arrow in the figure), and after positioning, the optical lens 42 is fixed to the glass substrate 41 using an ultraviolet-curing adhesive or the like. The positioning of the coil and the optical lens is not limited to the method described with reference to FIG. 24, but usually the positioning is often performed based on the shape of the inner circumference of the coil, as shown in FIG. 23. In the first coil 441, since the shape of the inner periphery is symmetrical, the positioning can be performed easily and accurately. As a result, it is possible to underestimate a margin in consideration of an error in the alignment between the coil and the optical lens, and to reduce the inner diameter of the coil by reducing the margin.

In addition, the innermost circumference 4 4 13 shown in FIG. 23 has an inner edge 4 4 13 a and an outer edge 4 4 13 b at equal intervals, and the inner edge 4 4 1 1 e to 5 Z Predetermined width part 4 4 1 3-1, which has circulated to a position of about 6 laps, and predetermined width part 4 4 1 3-1, while the outer edge 4 4 13 b gradually expands outward with respect to the inner edge 4 4 13a And a widened portion 4 13-2 circulating from the end in the circumferential direction to the end of the innermost circumferential portion 4 13. The widened portion 4 4 1 3-2 has a circumference of about 1/6. The innermost peripheral portion 4 4 13 is connected by a smooth curve, and the periphery of the innermost peripheral portion 4 4 13 is easily filled with alumina, which facilitates production.

The first coil 4 41 shown in FIG. 23 has the innermost peripheral portion 4 4 13 and the innermost peripheral portion 4 4 13 in the same plane as the plane around which the first coil 4 4 Spiral part 4 4 1 5 Spiral part 4 4 1 5 spiraling in the same direction as the innermost part 4 4 13 It consists of a connecting part 4 4 16 connecting the end in the circumferential direction of 4 13 and the start of the spiral in 4 4 15, and the spiral part corresponds to an example of the second conductor according to the present invention. The connection portion 4 4 16 corresponds to an example of the third conductor according to the present invention. The spiral portion 4 4 1 5 is composed of a first orbital portion 4 4 1 5—1 and an outer edge 4 4 1 3—2 of which a predetermined width portion 4 4 1 3—1 is equally spaced and a widened portion 4 4 1 3—2. It has alternately 3-2a and second circulating portions 4 4 1 5-2 which are circulated at equal intervals. In this way, by tracing the shape of the innermost circumferential portion 4 4 13 after the second round, the radial position approaches the point of application of the magnetic field. In this case, the generation efficiency of the magnetic field has been further enhanced.

FIG. 25 is an enlarged view of the inner peripheral end of the first coil shown in FIG. 23 from the optical lens side, and FIG. 26 is an inner peripheral end of the first coil shown in FIG. FIG. 4 is a diagram when an end portion is sectioned in a circumferential direction of the coil.

In the explanation here, the innermost peripheral portion 4 4 13 is divided into an inner peripheral end 4 4 11 and a peripheral portion connected to the inner peripheral end 4 4 1 1. The inner circumference part 51 will be referred to as the inner circumference part 51, and the circumference part adjacent to the innermost circumference part 51 in the radial direction will be referred to as the second circumference part 52.

The inner peripheral end portion 4411 of the first coil is such that an outer edge 4411a is inclined away from the second circular portion 52.

Here, as shown in FIG. 25, the distance between the innermost peripheral portion 51 and the second peripheral portion 52 at the boundary between the innermost peripheral portion 51 and the inner peripheral end portion 4411 is determined. From the midpoint A where the diameter is bisected, the diameter is 1.5 times the thickness h of the first coil 4 41 and the outer edge 4 4 1 1 a of the inner peripheral end 4 4 1 1 a and the second round Let L be the distance to the center B of the circle C 3 that touches both the inner edge 52 a of the orbiting portion 52 and L, as shown in FIG. 26, from the surface 43 a of the dielectric layer 43. The distance to the surface 4 4 1 a of one coil 4 4 1 is d.

In the first coil 4 41 of the present embodiment, a relationship of 2 X d> L is established. If the relationship of 2 X d> L is not established, the tip of the gap g ′ extending between the innermost orbital portion 51 and the second orbital portion 52 is indicated by a one-dot chain line in FIG. And appear on the polished surface of the layer made of alumina, that is, on the surface 43a of the dielectric layer 43, and an opening gl 'occurs. The inside of the gap g 'is in a vacuum state immediately after the formation of the dielectric layer 43, and the gap g' is filled with the abrasive (slurry) and the like at the moment when it appears on the surface by polishing. May be sucked into. Inhaled abrasive can cause corrosion of the coil. Also, when a resist is applied on the surface 43a where the opening gl 'is formed and the temperature is raised to dry the applied resist, the air in the gap g' expands and the opening g1 ' Air may blow out and create bubbles in the resist. In the area where bubbles are formed, the exposure of the coil pattern is insufficient when the coil pattern is exposed, resulting in an insufficient amount of exposure. When this is developed, the bubble portion remains as it is, making it impossible to form a proper pattern. However However, in the first coil 4 41 of the present embodiment, since the relationship of 2 X d> L holds, the gap g is formed by the dielectric layer 43 being clogged as indicated by the arrow in FIG. 26. The growth of ′ is suppressed, and the gap g ′ does not appear on the surface 43 a of the dielectric layer 43 (see the portion shown by the solid line).

Subsequently, a modified example of the first coil 441 shown in FIG. 23 will be described with reference to FIGS. 27 and 28. FIG.

FIG. 27 is a diagram illustrating a coil having an elliptical inner peripheral shape, and FIG. 28 is a diagram illustrating a coil having an elliptical inner peripheral shape.

In the coil 64 shown in FIG. 27, the inner edge 6 4 13 a of the innermost circumferential portion 6 4 13 a is substantially one round of the ellipse along the ellipse. In addition, the coil 65 shown in FIG. 28 has an inner edge 6513 a of the innermost peripheral portion 6513 a that extends along an ellipse that is a shape that connects two semicircles by a straight line. It is a round of the circle. When the passing position of the laser beam is decentered for the purpose of tracking the M〇 disk, it is preferable that the inner peripheral shape of the coil is such an ellipse or an ellipse. In the case of an elliptical or elliptical inner peripheral coil, the diameter of the coil is made larger than necessary by adjusting the eccentric direction of the laser beam (the direction of the tracking support) to the major axis direction of the inner peripheral shape. It becomes unnecessary.

In both coils 64 and 65 shown in Fig. 27 and Fig. 28, the inner peripheral shape is symmetrical to the left and right, making it easy to find the center of the coil, and the workability of positioning the coil and optical lens Is improved. Also, these coils 64 and 65, like the first coil 441 shown in FIG. 23, do not include the extra area S shown in FIG. A magnetic field is generated more efficiently than the coil 74. Further, in each of the coils 64, 65, as in the case of the first coil 441, shown in FIG. 23, the innermost orbital portions 641, 13 and 6513 and the spiral portion 64 It has 15 6 5 15 and connecting portions 6 4 16 6 5 16 and is the area indicated by the arrow in the figure among the innermost circumferential portions 6 4 13 3 and 65 13 The portion that enters is equivalent to the widened portion 4 4 1 3—2 of the first coil 4 41 shown in FIG. 23, and the portion outside that region is equivalent to the predetermined width portion 4 4 1 3—1. . Further, of the spiral portions 6415 and 6515, the portion that falls within the region indicated by the arrow in the figure is the second orbital portion 4411 referred to as the first coil 441 shown in FIG. 5-2, and the portion outside the area corresponds to the first orbital section 4 4 15 -1. In this case, the magnetic field generator having the upper and lower two-layer coils has been described. The present invention can be applied to a magnetic field generator having a coil or a magnetic field generator having a multilayer coil of three or more layers.

As described above, by making the inner peripheral shape of the coil symmetrical, the efficiency of generating the magnetic field of the coil can be increased. In addition, when the coil and the optical lens are aligned, it is easy to use the inner circumference of the coil as a reference, thereby improving the accuracy of the alignment and reducing the margin. As a result, the inner diameter of the coil can be reduced as much as the margin is reduced, and the magnetic field generation efficiency is further increased. Also, the inductance of the coil is reduced, and the coil can be driven at a higher frequency.

In addition, by setting the distance between the coil conductors to 0.4 to 0.8 times the thickness of the coil and forming a dielectric layer made of alumina by vacuum deposition, problems such as heat and insulation characteristics may occur. Without this, the diameter of the coil can be made smaller. In this way, the efficiency of generating the magnetic field is increased, and the power consumption is further reduced. In addition, the inductance of the coil is further reduced, and the coil can be driven at a higher frequency.

Claims

The scope of the claims

1. A first conductor having an inner edge substantially circling the shape along a predetermined shape symmetrical to the left and right, and an outside of the first conductor in the same plane as a plane around which the first conductor circulates. A second conductor spirally circling in the same direction as the circling direction;

A magnetic field generator comprising: a third conductor connecting a circumferential end of the first conductor and a circumferential start of the second conductor.

2. The first conductor has a predetermined width portion that is circulated from the start end in the circling direction of the first conductor with the inner edge and the outer edge kept at equal intervals, and the predetermined width portion where the outer edge gradually expands outward with respect to the inner edge. 2. The magnetic field generator according to claim 1, wherein the magnetic field generator comprises a widened portion which extends from a circumferential end of the first conductor to a circumferential end of the first conductor.

3. The second conductor alternately has a first circling portion circling at an equal interval with the predetermined width portion and a second circling portion circling at an equal interval with the outer edge of the widened portion. 2. The magnetic field generator according to claim 1, wherein:

4. a dielectric layer made of alumina;

A conductor spirally circling in the same plane inside the dielectric layer, wherein the conductor has a constant distance between adjacent radiating portions in the radial direction, and the distance is a thickness of the conductor. Magnetic field generation characterized by being 0.4 times or more and 0.8 times or less of

5. The magnetic field generator according to claim 4, wherein the conductor has a beveled edge extending in a circumferential direction.

6. The dielectric layer is provided on a glass substrate surface,

The claim is characterized in that the magnetic field generator is provided with an adhesion film for increasing the adhesion between the conductor and the dielectric layer on a surface of the conductor opposite to the glass substrate. 4. Magnetic field generator according to 4.

7. The conductor has an end that is inclined such that an outer edge is separated from a second circumferential part radially adjacent to the innermost circumferential part of the innermost circumference and that is connected to the innermost circumferential part. Thing,

The magnetic field generator may be configured such that the innermost circumference at a boundary between the innermost circumference portion and the end portion is From the midpoint that bisects the distance between the circling portion and the second circling portion, the outer edge of the end is 1.5 times the thickness of the conductor and the outer rim of the end and the second circulating portion. When the distance from the center of the circle tangent to both inner edges of the conductor is L and the distance from the surface of the dielectric layer to the surface of the conductor is d, the relationship 2 X d> L holds. 5. The magnetic field generator according to claim 4, wherein:

8. A medium storage unit that stores a plurality of disk-shaped magneto-optical storage media capable of recording and reproducing information and at least recording information by receiving light irradiation and a magnetic field, and the magneto-optical storage. A recording / reproducing unit for recording and / or reproducing information on / from a medium; a medium moving unit for moving the magneto-optical storage medium between the medium storing unit and the recording / reproducing unit; A plurality of magneto-optical information storage devices each including the medium moving unit and a blade housing integrally holding the recording / reproducing unit;

A system housing on which the plurality of magneto-optical information storage devices are mounted and which detachably holds the plurality of magneto-optical information storage devices;

A control unit that controls recording and / or reproduction of information in each of the plurality of magneto-optical information storage devices mounted on the system housing;

The recording and playback unit,

A first conductor whose inner edge is substantially wrapped around the shape along a predetermined shape symmetrical to the left and right, in the same plane as the plane around which the first conductor wrapped, A magnetic field generator having a second conductor spirally wound in the same direction, a third conductor connecting a circumferential end of the first conductor and a circumferential start of the second conductor, and a light source for emitting light With

Information is recorded on the magneto-optical storage medium by applying a magnetic field generated by the magnetic field generator to the magneto-optical storage medium and irradiating light emitted from the light source. Magneto-optical information storage system.

9. A medium storage unit that stores a plurality of disk-shaped magneto-optical storage media capable of recording and reproducing information and at least recording information by receiving light irradiation and a magnetic field, and the magneto-optical storage. A recording / reproducing unit for recording and / or reproducing information on / from a medium; and the magneto-optical storage medium between the medium storage unit and the recording / reproducing unit. A plurality of magneto-optical information storage devices each including a medium moving unit that moves a body, and a blade housing that integrally holds the medium storing unit, the medium moving unit, and the recording and reproducing unit;

The recording and playback unit,

A dielectric layer made of alumina; and a conductor spirally circulating in the same plane inside the dielectric layer, wherein the conductor has a constant interval between circling portions adjacent in the radial direction. A magnetic field generator having an interval of 0.4 to 0.8 times the thickness of the conductor;

With a light source that emits light,

10. Magneto-optical information that records and / or reproduces information on a disk-shaped magneto-optical storage medium on which information recording can be performed at least by receiving light irradiation and a magnetic field capable of recording and reproducing information A storage device,

A recording / reproducing unit that records and / or reproduces information with respect to the magneto-optical storage medium; a medium moving unit that moves the magneto-optical storage medium between the medium storage unit and the recording / reproducing unit;

The recording / reproducing unit, ^ 1 conductor whose inner edge is substantially circumnavigated along a predetermined shape symmetrical to the left and right, in the same plane as the plane around which the first conductor circulates, the outside of the first conductor and the circling direction of the first conductor A magnetic field generator having a second conductor spirally wound in the same direction, a third conductor connecting a circumferential end of the first conductor and a circumferential start of the second conductor, and a light source for emitting light With

Information is recorded on the magneto-optical storage medium by applying a magnetic field generated by the magnetic field generator to the magneto-optical storage medium and irradiating light emitted from the light source. Magneto-optical information storage device.

1 1. Magneto-optics for recording and / or reproducing information on a disk-shaped magneto-optical storage medium on which information can be recorded and reproduced by at least information recording by receiving light irradiation and magnetic field application An information storage device,

The recording and playback unit,

With a light source that emits light,