WO2004097823A1 - 磁界発生器、光磁気情報記憶システム、および光磁気情報記憶装置 - Google Patents
磁界発生器、光磁気情報記憶システム、および光磁気情報記憶装置 Download PDFInfo
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- WO2004097823A1 WO2004097823A1 PCT/JP2003/005337 JP0305337W WO2004097823A1 WO 2004097823 A1 WO2004097823 A1 WO 2004097823A1 JP 0305337 W JP0305337 W JP 0305337W WO 2004097823 A1 WO2004097823 A1 WO 2004097823A1
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- coil
- magneto
- magnetic field
- recording
- information
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Classifications
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B11/00—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor
- G11B11/10—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field
- G11B11/105—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field using a beam of light or a magnetic field for recording by change of magnetisation and a beam of light for reproducing, i.e. magneto-optical, e.g. light-induced thermomagnetic recording, spin magnetisation recording, Kerr or Faraday effect reproducing
- G11B11/10532—Heads
- G11B11/10534—Heads for recording by magnetising, demagnetising or transfer of magnetisation, by radiation, e.g. for thermomagnetic recording
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B11/00—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor
- G11B11/10—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field
- G11B11/105—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field using a beam of light or a magnetic field for recording by change of magnetisation and a beam of light for reproducing, i.e. magneto-optical, e.g. light-induced thermomagnetic recording, spin magnetisation recording, Kerr or Faraday effect reproducing
- G11B11/1055—Disposition or mounting of transducers relative to record carriers
- G11B11/10552—Arrangements of transducers relative to each other, e.g. coupled heads, optical and magnetic head on the same base
- G11B11/10554—Arrangements of transducers relative to each other, e.g. coupled heads, optical and magnetic head on the same base the transducers being disposed on the same side of the carrier
Definitions
- magnetic field generator magneto-optical information storage system
- magneto-optical information storage device magneto-optical information storage device
- the present invention relates to a magnetic field generator for generating a magnetic field, and a magneto-optical information storage device for recording and reproducing information on a magneto-optical storage medium on which at least information is recorded by receiving light irradiation and a magnetic field.
- the present invention relates to a magneto-optical information storage system integrating a plurality of magneto-optical information storage devices.
- information recording media such as CD, CD-ROM, CD-R, DVD, PD, MO, and MD have been widely used as large-capacity recording media for storing audio signals and image signals.
- 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.
- 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.
- the temperature of a recording film of a recording medium is brought close to one point of a Curie by condensing a laser beam for recording, and in that state, the temperature is generated by a coil.
- a magnetic field 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.
- 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 using 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. This makes it possible to realize a magnetic field coil that can be driven at high speed.
- FIG. 1 is a schematic diagram showing a structure of a general front illumination type magnetic field generator.
- 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.
- a magnetic field coil composed of such a thin film can be manufactured by a semiconductor process.
- the coil when the coil is energized, the coil generates heat.
- the electrical resistance of a material increases with increasing temperature. Therefore, if the heat generated by the coil is not efficiently dissipated, the coil will generate a vicious cycle in which the heat generated by the coil will increase its own power consumption and increase the amount of heat generated. Since the thermal conductivity of the dielectric layer on which the coil is provided is not very good, the heat generated by the coil is not easily dissipated, the temperature of the coil rises at an accelerated rate, and the coil generates a magnetic field of a predetermined strength It may be damaged before doing so. Therefore, radiating the heat generated by the coil is an important issue.
- FIG. 2 is a diagram showing a state in which a metal having a high thermal conductivity is arranged around the coil.
- FIG. 3 is a diagram showing a state when current is supplied to the coil shown in FIG. 2 from the magneto-optical recording medium side.
- a coil 74 Inside a dielectric layer 73 made of alumina provided on a glass substrate 71 shown in FIG. 2, a coil 74, a yoke 75, and a heat radiator 76 are provided.
- the coil 74 is formed in a spiral shape so as to surround a region through which the laser light L passes.
- the heat radiator 76 is a nonmagnetic metal film that spreads around the coil 74.
- the yoke 75 is a magnetic film that extends between the coil 74 and the glass substrate 71 so as to cover the coil-side portion of the coil 74 and the radiator 75.
- the yoke 75 functions not only as a magnetic core of the coil but also as a heat radiating path for heat generated in the coil 74 because the yoke 75 has a higher thermal conductivity than the dielectric layer 73.
- the heat generated in the coil 74 shown in FIG. 2 is radiated to the outside from the radiator 76 through the yoke 75.
- the present invention provides a magnetic field generator capable of efficiently dissipating heat generated in a coil while suppressing a decrease in magnetic field generation efficiency due to eddy current, and a magneto-optical storage device including the magnetic field generator. It is an object of the present invention to provide a magneto-optical information storage system including a plurality of magneto-optical storage devices.
- a magnetic field generator according to the present invention that achieves the above object includes a coil that spirals in one plane and is covered with a dielectric material,
- a magnetic body provided in parallel with the plane so as to overlap with the coil, a projection extending in the plane so as to surround the coil and projecting toward the outermost periphery of the coil, and a projection direction of the projection
- a radiator having a thermal conductivity higher than that of the magnetic material, which is provided alternately and repeatedly with grooves depressed in the opposite direction.
- the eddy current flowing in the groove is smaller than the eddy current flowing in the protrusion because the eddy current is more distant from the coil than the portion.
- the reduction in efficiency can be kept within an acceptable range.
- the closer the tip of the protrusion is to the coil the easier it is to radiate the heat generated by the coil, and since the radiator spreads out to surround the coil, It is larger than the area of the spiral pattern of the coil, and has a sufficient heat radiation effect.
- the magnetic body extends parallel to the plane to a position corresponding to a position between the protrusions while avoiding overlap with the protrusions.
- the magnetic body extends parallel to the plane to a position corresponding to a position between the protrusions while avoiding overlap with the protrusions.
- the coil is spirally wound around a predetermined area of the plane
- the magnetic body is composed of a plurality of strips extending radially around a region overlapping the predetermined region.
- the magnetic material collects magnetic flux generated around the current flowing through the coil in itself. It has a function of bundling, and the generated magnetic flux is focused on a magnetic body extending to a position corresponding to between the protrusions, and the magnetic flux passing through the protrusions is reduced. For this reason, even if the tip of the protrusion is brought close to the coil in order to improve the heat dissipation efficiency, the amount of eddy current flowing through the protrusion is reduced, and the decrease in the magnetic field generation efficiency is suppressed.
- the non-magnetic material is disposed between the strips adjacent to each other, and extends so as to overlap the protrusion and the coil, and has a higher thermal conductivity than the dielectric material.
- An embodiment with a body is more preferred. Since the magnetic material has better thermal conductivity than the dielectric material covering the coil, it also functions as a heat radiation path for heat generated in the coil. The use of the magnetic material leads to a reduction in the area of the heat radiation path, and the heat radiation efficiency using the magnetic material is reduced. Therefore, by disposing the non-magnetic material, a heat radiation path for the heat generated in the coil is secured, and the heat radiation efficiency is further increased. The magnetic flux generated in the coil does not converge on the non-magnetic material. Therefore, the generation of the eddy current is compared with the magnetic material even in the portion of the non-magnetic material overlapping the coil. It is slight.
- the magnetic field generator further includes a magnetic material provided in the recess of the groove, covered with a dielectric material, and having a larger volume resistivity than the heat radiator.
- the magnetic material has a larger volume resistivity than the heat radiator, the eddy current generated in the magnetic material is more than the eddy current generated in the protrusion by omitting the magnetic material. Therefore, it is possible to suppress a decrease in the magnetic field generation efficiency and to reduce the amount of heat generated by the eddy current.
- the protrusion is an outermost periphery of the coil. It is also preferable that the width becomes narrower toward.
- the magneto-optical information storage system of the present invention that achieves the above object has a disk-shaped magneto-optical storage medium capable of recording and reproducing information and at least performing information recording by receiving light irradiation and application of a magnetic field.
- a plurality of magneto-optical information storage devices each comprising: a medium moving unit for moving the medium; and a blade housing that integrally holds the medium storing 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 radiator having a heat conductivity higher than that of the magnetic material, in which protrusions protruding toward the outermost periphery of the coil and grooves recessed in a direction opposite to the protrusion direction of the protrusions are alternately and repeatedly provided.
- a magnetic field generator having
- a magneto-optical information storage device that achieves the above object is a disk-shaped magneto-optical storage medium 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 by
- 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 section, the medium moving section, and the recording / reproducing section are arranged in a line, and the medium housing section, the medium moving section, and the recording / reproducing section 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 / reproducing unit is
- a radiator having a heat conductivity higher than that of the magnetic material, in which protrusions protruding toward the outermost periphery of the coil and grooves recessed in a direction opposite to the protrusion direction of the protrusions are alternately and repeatedly provided.
- a magnetic field generator having
- 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.
- a magnetic field generator capable of efficiently radiating heat generated in a coil while suppressing a decrease in magnetic field generation efficiency due to eddy current, and the magnetic field generator.
- a magneto-optical storage device and a magneto-optical information storage system including a plurality of the magneto-optical storage devices can be provided.
- Figure 1 shows the structure of a typical front illumination type magnetic field generator. It is a schematic diagram.
- Fig. 2 is a view showing a state in which a metal with high thermal conductivity is arranged around the coil.
- Fig. 3 is a view when the coil shown in Fig. 2 is energized, viewed from the magneto-optical recording medium side.
- FIG. 4 is an external view showing each embodiment of the optical information storage system and the optical information storage device of the present invention.
- FIG. 5 is a diagram showing details of the magazine.
- FIG. 6 is a diagram illustrating a hardware structure of the blade device.
- FIG. 7 is a functional block diagram showing the functional structure of the blade device.
- FIG. 8 is a diagram illustrating a structure near the head of the drive.
- FIG. 9 is a sectional view schematically showing a partial structure of the magnetic field generator shown in FIG.
- FIG. 10 is a schematic diagram showing the internal structure of the dielectric layer when the magnetic field generator is viewed from the MO disk side.
- FIG. 11 is a diagram of a state where power is applied to the coil surrounded by a radiator having a protrusion that becomes narrower toward the coil, as viewed from the MO disk side.
- FIG. 12 is a view of a dielectric layer in which a heat conductor is provided between strips adjacent to each other, as viewed from the glass substrate side.
- FIG. 13 is a cross-sectional view schematically showing a partial structure of the magnetic field generator of the second embodiment.
- FIG. 14 is a schematic diagram showing the internal structure of the dielectric layer when the magnetic field generator shown in FIG. 13 is viewed from the M ⁇ disk side.
- FIG. 4 is an external view showing each embodiment of the optical information storage system and the optical information storage device of the present invention.
- FIG. 4 shows a magneto-optical (MO) disk as an example of the optical storage medium according to the present invention.
- An optical information storage system according to the present invention in which a blade device 10 corresponding to one embodiment of the optical information storage device of the present invention and a plurality of (10 in this figure) blade devices 10 are incorporated.
- An aggregation system 20 corresponding to one embodiment is shown.
- the housing 11 of the blade device 10 has a length exceeding three times the diameter of the M ⁇ disk, a width slightly larger than the diameter of the MO disk (height in this figure), and a length greater than the diameter of the MO disk. Has a significantly smaller thickness (width in this figure), and a magazine 12 containing a plurality of M ⁇ 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.
- 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.
- the capacity can be easily expanded by increasing the number of MO 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. 5 is a diagram showing details of the magazine.
- Part (A) of FIG. 5 is a perspective view showing a state in which a plurality of MO disks 13 are stored in the magazine 12, and an enlarged view of a range P surrounded by a chain line.
- a cross-sectional view is shown in part (B) of FIG.
- a removable FRAM I 4 is inserted into the magazine 12, and the terminal 14 a of the FRAM 14 contacts the internal terminal 12 a provided in the magazine 12, and It is electrically connected to the external terminal 1 2b connected to the internal terminal 12a.
- the external terminal 12 b 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. RAM I 4 can be read and written.
- FR AM 14 has storage locations for each MO disk 13 in magazine 12 Is recorded.
- a MO disk 13 of a type capable of recording information on both sides is used, and a recording film is provided on both sides 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. 4 has a structure that can simultaneously access the front and back of the MO disk 13.
- FIG. 6 is a diagram illustrating a hardware structure of the blade device.
- the blade device 10 also illustrated in FIG. 4 includes the above-described magazine 12 and a drive 16 for recording and reproducing information on and from the MO disk 13 in a housing 11. Between the drive 12 and the drive 16, a changer 15 for moving the MO disk 13 between them is provided.
- the drive 16 corresponds to an example of the recording / reproducing unit according to the present invention
- the changer 15 corresponds to an example of the medium moving unit according to the present invention.
- the blade device 10 is a compact storage of the magazine 12, the changer 15, and the drive 16 in the housing 11, and as long as there is free space in the magazine 12, the MO disk
- the storage capacity can be easily expanded by increasing 13.
- maintenance can be easily performed by attaching / detaching or replacing the magazine 12 or the M ⁇ disk 13.
- a connector 17 a of an interface for transferring data between the blade device 10 and the outside is provided, and the blade device 10 is When the connector 17a is inserted into the housing 21 of the collective system 20 shown in FIG. 4, the connector 17a is joined to the connector of the collective system 20.
- the connector 17a corresponds to an example of the connecting portion according to the present invention.
- the changer 15 has a function to insert and remove the MO disk 13 from the magazine 12, a function to move the MO disk 13 up and down in the figure, and a function to set the M ⁇ disk 13 to the drive 16. It has a function to take out from drive 16.
- the housing 11 in the present embodiment has a length three times or more the length of the M ⁇ disk 13, but the changer 15 and the drive 16 are mounted on the changer 15.
- MO disk 13 and MO disk 13 loaded in drive 16 The blade housings can be arranged in such a positional relationship as to cause overlapping, and the length of the blade housing according to the present invention is preferably at least 2.5 times the diameter of the optical storage medium.
- FIG. 7 is a functional block diagram showing the functional structure of the blade device.
- 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 a data transfer between the blade device 10 and the outside.
- An interface 17 is also provided.
- the interface 17 is selected from well-known high-speed serial interfaces such as IEEE 1394, USB, serial ATA, etc., and the details are omitted.
- the drive 16 is provided with a spindle motor 161 for holding and rotating the MO disk, and a head 162 for irradiating light to the MO disk to record and reproduce information. Two are provided for each of the first and second sides of the MO disk (front and back).
- the drive 16 also includes a read / write channel 163 for each of the first and second sides, and a first-in first-out (FIFO) memory 164 that functions as a buffer.
- FIFO first-in first-out
- the control unit 18 receives, via the interface 17, designation information for designating an MO disk from outside the device via a path (not shown).
- the control unit 18 finds the designated M disk from among the plurality of MO disks stored in the magazine 12 based on the designated information, and sends the designated M disk to the changer 15. Instruct that the found MO disk should be set from magazine 12 to drive 16.
- the changer 15 takes out the MO disk specified by the control unit 18 from the magazine 12 and sets it in the drive 16. That is, since the control unit 18 can find the MO disk to be accessed based on the storage information of the FRAMI 4, the access can be started quickly even when the magazine 12 is replaced, for example. .
- 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 and bypassing the control unit 18, so that when the blade device 10 is turned off.
- the stored information of the FRAM 14 can be externally confirmed through the access path 19.
- FIG. 8 is a diagram illustrating a structure near the head of the drive.
- the drive 16 is provided with two heads 16 2.
- FIG. 8 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.
- Each head 16 2 is mounted on a drive base (not shown). It is composed of a fixed assembly 32 that is fixed, and a moving 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
- 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
- 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 M ⁇ ⁇ ⁇ disk 13, applies a magnetic field, and is further reflected by the MO disk 13. It has the function of returning the reflected light to the measurement 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.
- FIG. 9 is a cross-sectional view schematically showing a partial structure of the magnetic field generator shown in FIG. 8, and FIG. 10 is a view showing the internal structure of the dielectric layer when the magnetic field generator is viewed from the MO disk side.
- FIG. 10 is a cross-sectional view schematically showing a partial structure of the magnetic field generator shown in FIG. 8, and FIG. 10 is a view showing the internal structure of the dielectric layer when the magnetic field generator is viewed from the MO disk side.
- the magnetic field generator 40 shown in FIG. 9 has a glass substrate 42 provided with an optical lens 41 on one surface.
- a dielectric layer 43 is formed on a surface of the glass substrate 42 opposite to the surface on which the optical lens 41 is provided.
- the magnetic field generator 40 is mounted on the moving assembly 31 so that the optical lens 41 faces the condenser lens 35 and the dielectric layer 43 faces the M ⁇ disk 13 set on the drive 16.
- the laser beam narrowed down by the condenser lens 35 is further narrowed down by an optical lens 41 provided on the glass substrate 42 and transmitted through the glass substrate 42 and the dielectric layer 43.
- the M ⁇ disk 13 is irradiated.
- the dielectric layer 43 shown in FIG. 9 is made of alumina having a relatively high thermal conductivity, and its thermal conductivity is around 2 OW / mK.
- a coil 431, a yoke 432, and a heat radiator 433 are provided inside the dielectric layer 43.
- the coil 43 1 spirally surrounds the dielectric layer 43 so as to surround the transmission region C through which the laser beam passes. As shown in the figure, it is provided in two upper and lower stages. In the spiral coil 431 provided over the upper and lower two stages, the upper part and the lower part are connected to each other at the innermost end surrounding the transmission region C.
- the yoke 432 is disposed between the coil 431 and the glass substrate 42 so as to overlap the coil 431.
- the yoke 432 is formed of a plurality of strips made of a soft magnetic material such as a perm-type C O N i Fe alloy extending radially around the transmission region C.
- the thermal conductivity is higher than that of the alumina constituting the dielectric layer 43. Therefore, each of the strips 432 converges the magnetic flux generated around the current flowing through the coil 431 into itself, and also functions as a heat radiation path for the heat generated by the coil 431.
- the heat radiator 4 3 3 is a copper metal film that extends so as to surround the coil 4 3 1 in the same plane as the plane on which the coil 4 3 1 is provided, and its area is the area of the spiral pattern of the coil 4 3 1. Much larger than.
- the thermal conductivity of copper is about 40 OW / mK, which is 20 times that of alumina, and is higher than the thermal conductivity of a yoke 432 such as permalloy or a CoNiFe alloy. Therefore, the heat radiator 4 33 has a sufficient heat radiation effect.
- the heat radiator 433 is not limited to a copper metal film, but may be any material having a higher thermal conductivity than the yoke 432.
- the radiator 4 33 has a protrusion 4 3 3 1 protruding toward the outermost circumference of the coil 4 3 1, and a groove 4 which is recessed in a direction opposite to the protrusion direction of the protrusion 4 3 3 1. 3 3 and 2 are alternately repeated. As shown in FIG.
- the heat radiator 4 3 3 is provided on a plane different from the plane on which the yoke 4 3 2 is provided, and the plurality of strips 4 3 2 1 constituting the yoke 4 3 2 are As shown in FIG. 10, avoiding overlapping with the protrusions 4 3 3 1, the grooves 4 3 3 2 extend to the depressions, that is, the corresponding positions between the adjacent protrusions 4 3 3 1 .
- the heat generated in the upper portion of the coil 43 1 is transmitted to the radiator 4 3 3 via the strip 4 3 21, or Alternatively, the heat is directly transmitted to the protrusions 4 3 3 1 of the heat radiator 4 3 3, and in any case, the heat is radiated by the heat radiator 4 3 3.
- the heat generated in the lower portion of the coil 431 is mainly transmitted to the protrusion 433 of the radiator 433 and is radiated by the radiator 433. According to experiments, when a magnetic field of 200 [Oe] is generated in the coil at a driving frequency of 30 MHz, the temperature of the coil of the conventional structure shown in FIG.
- the protrusions 4 3 3 1 of the heat radiating section 4 3 3 were placed 7 to 10 m from the outermost circumference of the coil 4 3 1, and the width of the protrusions 4 3 3 1
- the temperature of the coil is suppressed to a rise of about 65 ° C, and the heat generated by the coil is reduced. It was confirmed that heat radiation was performed efficiently.
- the magnetic flux generated around the current flowing through the coil 431 by energizing the coil 431 focuses on the strip 4321, which extends to a position corresponding to the depression of the groove 4333. As a result, the magnetic flux passing through the protrusion 4 3 3 1 decreases.
- the width of the protrusion 4331 is reduced toward the coil 431.
- FIG. 11 is a diagram of a state where power is applied to a coil surrounded by a radiator having a protrusion that becomes narrower toward the coil as viewed from the M ⁇ disk side.
- the heat radiator 4 33 3 is a conductor because it is a copper metal film.
- An induced current eddy current
- the strength of the magnetic field created by the current is inversely proportional to the square of the distance.
- the protrusion 4331 when the protrusion 4331 is made narrower toward the coil 431, the magnetic flux passing through the protrusion 4331 can be further reduced.
- the eddy current flowing through the part 4 3 3 1 is further reduced. Since the groove 4 3 3 2 is farther from the coil 4 3 1 than the protrusion 4 3 3 1, the eddy current flowing in the groove 4 3 3 2 is smaller than the eddy current flowing in the protrusion 4 3 3 1. In view of the total amount of eddy current flowing through the heat radiator 4 3 3 However, it is kept within a range that can be sufficiently accepted.
- each of the plurality of strips 4 3 2 1 constituting the yoke 4 3 2 has a considerably narrow width in order to reduce the magnetic flux passing through the protrusions 4 3 3 1 so as to avoid overlapping with the protrusions 4 3 3 1. It has become. For this reason, when there is a concern that the function as a heat radiation path is reduced due to the decrease in the area of the yoke 432, it is preferable to dispose a heat transfer material between the strips 4321 adjacent to each other.
- FIG. 12 is a view of a dielectric layer in which a heat conductor is provided between strips adjacent to each other, as viewed from the glass substrate side.
- FIG. 12 when viewed from the glass substrate side, the yoke 4 32 is shown in front of the paper surface, and the coil 4 31 1 and the radiator 4 3 3 located on the back side of the yoke 4 3 2 are indicated by dotted lines. It is shown.
- FIG. 12 also shows a heat transfer body 44.
- the heat transfer body 44 shown in FIG. 12 is a metal film made of copper, and a protrusion 4 3 3 1 and a coil 4 3 1 of the heat radiator 4 3 3 are formed between the strips 4 3 2 1 adjacent to each other. And a peripheral part 442 connecting adjacent ones of the extending parts 441 via the strips 4321.
- the thermal conductivity of copper is about 400 [W / m K], which is much higher than the thermal conductivity of alumina that forms the dielectric layer, and is the permalloy that forms the yoke 4 32. Since the heat conductivity of the CoNiFe alloy is about 80 to 100 [W / mK], the heat transfer member 44 conducts heat more easily than the yoke 432. Therefore, the heat generated in the coil 431 is finally transmitted to the radiator 433 through the extending portion 441 of the heat transfer member 44, and the heat generated in the coil 431 is further reduced. Heat is dissipated efficiently.
- the heat transfer member 44 is a non-magnetic material because it is made of copper, and the magnetic flux generated by the coil 43 1 does not converge on the heat transfer member 44. For this reason, the generation of the eddy current is slight even in the portion of the extension portion 441 that overlaps the coil 431 as compared with the yoke 432 which is a magnetic material.
- FIG. 13 is a cross-sectional view schematically showing a partial structure of the magnetic field generator of the second embodiment.
- FIG. 14 is a view showing the inside of the dielectric layer when the magnetic field generator is viewed from the M ⁇ disk side. It is a schematic diagram which shows a structure. Also in this case, the same components as those described above are denoted by the same reference numerals, overlapping description will be omitted, and only the description of the characteristic points will be made.
- a characteristic point of the magnetic field generator 40 shown in FIG. 13 is that a magnetic body 45 is provided in a recess of the groove 4333 of the heat radiator 43. That is, as shown in FIG. 14, the magnetic material 45 is provided on the same surface of the dielectric layer 43 as the surface on which the coil 431 is provided.
- the magnetic body 45 is a plate piece having a larger volume resistivity than that of the heat radiator 433.
- the yoke 4 32 shown in FIG. 13 is a doughnut-shaped soft magnetic film surrounding a transmission region through which the laser light passes. This yoke 432 is not in contact with the projection 4333 of the heat radiator 433, and a dielectric material is interposed between the yoke 4332 and the projection 4331. However, as shown in FIG.
- the magnetic body 45 In the magnetic field generator 40 shown in FIG. 13, the magnetic material 45 attracts the magnetic flux generated around the current flowing through the coil 431, and the magnetic flux passing through the protrusion 4331 decreases. For this reason, the tip of the protrusion 4331 shown in FIG. 13 extends to a position closer to the coil 431, compared to the tip of the protrusion shown in FIG. 11, but the protrusion shown in FIG. At the tip of the part 4331, only the eddy current generated at the tip of the protrusion shown in Fig. 11 occurs.
- the heat radiation efficiency by the protrusion 4 3 3 1 is increased.
- the magnetic body 45 is made of a permalloy or a CoNiFe alloy like the yoke 432, the thermal conductivity is inferior to that of the heat radiator 433 made of copper.
- the protrusions 4331 and the magnetic material 45 are alternately arranged around the coil 431, and the protrusions 4331 contribute to heat radiation of the heat generated by the coil 431.
- the magnetic material 45 contributes to the reduction of eddy current.
- the heat radiator 43 3 made of copper is arranged close to the coil 4 31.
- the efficiency of heat radiation from the coil 431 is improved.
- it is possible to reduce the eddy current generated inside the heat radiating body 4 3 3 it is possible to reduce the magnetic field attenuation due to eddy currents.
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2004571286A JPWO2004097823A1 (ja) | 2003-04-25 | 2003-04-25 | 磁界発生器、光磁気情報記憶システム、および光磁気情報記憶装置 |
PCT/JP2003/005337 WO2004097823A1 (ja) | 2003-04-25 | 2003-04-25 | 磁界発生器、光磁気情報記憶システム、および光磁気情報記憶装置 |
AU2003235131A AU2003235131A1 (en) | 2003-04-25 | 2003-04-25 | Magnetic field generator, magneto-optical information storage system, and magneto-optical information storage device |
US11/082,173 US7583171B2 (en) | 2003-04-25 | 2005-03-16 | Magnetic field generator, photomagnetic information storing system, and photomagnetic information storing apparatus |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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PCT/JP2003/005337 WO2004097823A1 (ja) | 2003-04-25 | 2003-04-25 | 磁界発生器、光磁気情報記憶システム、および光磁気情報記憶装置 |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US11/082,173 Continuation US7583171B2 (en) | 2003-04-25 | 2005-03-16 | Magnetic field generator, photomagnetic information storing system, and photomagnetic information storing apparatus |
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WO2004097823A1 true WO2004097823A1 (ja) | 2004-11-11 |
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PCT/JP2003/005337 WO2004097823A1 (ja) | 2003-04-25 | 2003-04-25 | 磁界発生器、光磁気情報記憶システム、および光磁気情報記憶装置 |
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JP (1) | JPWO2004097823A1 (ja) |
AU (1) | AU2003235131A1 (ja) |
WO (1) | WO2004097823A1 (ja) |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0476844A (ja) * | 1990-07-19 | 1992-03-11 | Sony Corp | 磁界変調型オーバーライト磁気ヘッド及びその製法 |
JPH11250402A (ja) * | 1998-02-27 | 1999-09-17 | Sony Corp | 光磁気ディスク装置とこれに使用される磁界発生装置及びその製造方法 |
JP2000036141A (ja) * | 1998-05-11 | 2000-02-02 | Quantum Corp | フライング光ヘッドアセンブリおよび光ディスクドライブデ―タ記憶システム |
JP2001023260A (ja) * | 1999-07-08 | 2001-01-26 | Sony Corp | 磁界変調用磁気ヘッド、磁気光学素子、光学ピックアップ装置および光ディスク装置 |
JP2002230860A (ja) * | 2000-10-10 | 2002-08-16 | Hitachi Maxell Ltd | 光磁気ヘッド及びそれを用いた光磁気記録装置 |
JP2003051144A (ja) * | 2001-08-03 | 2003-02-21 | Fujitsu Ltd | 磁気ヘッド |
-
2003
- 2003-04-25 AU AU2003235131A patent/AU2003235131A1/en not_active Abandoned
- 2003-04-25 JP JP2004571286A patent/JPWO2004097823A1/ja active Pending
- 2003-04-25 WO PCT/JP2003/005337 patent/WO2004097823A1/ja active Application Filing
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0476844A (ja) * | 1990-07-19 | 1992-03-11 | Sony Corp | 磁界変調型オーバーライト磁気ヘッド及びその製法 |
JPH11250402A (ja) * | 1998-02-27 | 1999-09-17 | Sony Corp | 光磁気ディスク装置とこれに使用される磁界発生装置及びその製造方法 |
JP2000036141A (ja) * | 1998-05-11 | 2000-02-02 | Quantum Corp | フライング光ヘッドアセンブリおよび光ディスクドライブデ―タ記憶システム |
JP2001023260A (ja) * | 1999-07-08 | 2001-01-26 | Sony Corp | 磁界変調用磁気ヘッド、磁気光学素子、光学ピックアップ装置および光ディスク装置 |
JP2002230860A (ja) * | 2000-10-10 | 2002-08-16 | Hitachi Maxell Ltd | 光磁気ヘッド及びそれを用いた光磁気記録装置 |
JP2003051144A (ja) * | 2001-08-03 | 2003-02-21 | Fujitsu Ltd | 磁気ヘッド |
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AU2003235131A1 (en) | 2004-11-23 |
JPWO2004097823A1 (ja) | 2006-07-13 |
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