JP4743782B2 - Near-field optical recording element, near-field optical head, and information recording / reproducing apparatus - Google Patents

Description

  The present invention relates to a near-field optical recording element capable of recording various kinds of information on a magnetic recording medium at a very high density using near-field light, a near-field optical head having the near-field optical recording element, and the near-field The present invention relates to an information recording / reproducing apparatus having an optical head.

  In recent years, the recording density of information within a single recording surface has increased as the capacity of hard disks and the like in computer equipment has increased. For example, in order to increase the recording capacity per unit area of the magnetic disk, it is necessary to increase the surface recording density. However, as the recording density increases, the recording area occupied by one bit on the recording medium decreases. When this bit size is reduced, the energy of 1-bit information is close to that of room temperature, and the recorded information is reversed or lost due to thermal fluctuation, etc. Will occur.

  In the in-plane recording method that has been generally used, the magnetism is recorded so that the direction of magnetization is in the in-plane direction of the recording medium. In this method, the recorded information is lost due to the thermal demagnetization described above. Is likely to occur. Therefore, in order to solve such a problem, a shift is being made to a perpendicular recording method in which a magnetization signal is recorded in a direction perpendicular to the recording medium. This method is a method for recording magnetic information on the principle of bringing a single magnetic pole closer to a recording medium. According to this method, the recording magnetic field is directed substantially perpendicular to the recording film. Information recorded by a perpendicular magnetic field is easy to maintain in energy stability because it is difficult for the N pole and the S pole to form a loop in the recording film surface. Therefore, this perpendicular recording method is more resistant to thermal demagnetization than the in-plane recording method.

  However, recent recording media are required to have a higher density in response to the need to record and reproduce a larger amount and higher density information. For this reason, in order to minimize the influence of adjacent magnetic domains and thermal fluctuations, those having a strong coercive force have begun to be adopted as recording media. For this reason, it is difficult to record information on a recording medium even in the above-described perpendicular recording system.

Therefore, in order to solve this problem, there is a hybrid magnetic recording method (near-field light assisted magnetic recording method) in which the magnetic domain is locally heated by near-field light to temporarily reduce the coercive force, and writing is performed during that time. Is provided. This hybrid magnetic recording system is a system that uses near-field light generated by the interaction between a minute region and an optical aperture formed in a size equal to or smaller than the wavelength of light formed in the near-field optical head. Thus, by using a small optical aperture that exceeds the diffraction limit of light, that is, a near-field light head having a near-field light generating element, the wavelength of light that has been limited in the conventional optical system can be reduced. It is possible to handle the optical information in the region. Therefore, it is possible to achieve a higher recording bit density than conventional optical information recording / reproducing apparatuses.
Note that the near-field light generating element is not limited to the above-described optical micro-aperture, and may be constituted by, for example, a protrusion formed in a nanometer size. This projection can also generate near-field light in the same manner as the optical minute aperture.

Various types of recording heads based on the hybrid magnetic recording system described above are provided, and one of them is a magnetic recording head in which the recording density is increased by reducing the size of the light spot. (For example, see Patent Documents 1 and 2).
This magnetic recording head mainly includes a main magnetic pole, an auxiliary magnetic pole, a coil winding in which a helical conductor pattern is formed inside an insulator, and a metal scatterer that generates near-field light from irradiated laser light. A planar laser light source that irradiates the metal scatterer with laser light, and a lens that focuses the irradiated laser light. Each of these components is attached to the front end surface of a slider fixed to the front end of the beam.

One end of the main magnetic pole is a surface facing the recording medium, and the other end is connected to the auxiliary electrode. That is, the main magnetic pole and the auxiliary electrode constitute a single magnetic pole type vertical head in which one magnetic pole (single magnetic pole) is arranged in the vertical direction. The coil winding is fixed to the auxiliary electrode so that part of the coil winding passes between the magnetic pole and the auxiliary electrode. These magnetic poles, auxiliary electrodes, and coil windings constitute an electromagnet as a whole.
The metal scatterer made of gold or the like is attached to the tip of the main magnetic pole. The planar laser light source is disposed at a position separated from the metal scatterer, and the lens is disposed between the planar laser light source and the metal scatterer.
Each component described above is attached in the order of the auxiliary magnetic pole, the coil winding, the main magnetic pole, the metal scatterer, the lens, and the planar laser light source from the front end surface side of the slider.

When the magnetic recording head configured in this way is used, various information is recorded on the recording medium by generating a near-field light and simultaneously applying a recording magnetic field.
In other words, laser light is irradiated from a planar laser light source. This laser beam is focused by a lens and irradiated onto a metal scatterer. Then, in the metal scatterer, the internal free electrons are uniformly oscillated by the electric field of the laser beam, so that the plasmon is excited to generate near-field light at the tip portion. As a result, the magnetic recording layer of the recording medium is locally heated by near-field light, and the coercive force temporarily decreases.
Simultaneously with the irradiation of the laser beam, a recording current is locally applied to the magnetic recording layer of the recording medium close to the main pole by supplying a driving current to the conductor pattern of the coil winding. Thereby, various types of information can be recorded on the magnetic recording layer whose coercive force has temporarily decreased. That is, recording on a recording medium can be performed by the cooperation of near-field light and a magnetic field.

Furthermore, a magnetic recording head in which a preheating mechanism is further combined with the above-described magnetic recording head is also known (for example, see Patent Document 3).
This magnetic recording head includes a resistance heater as a preheating mechanism between the main magnetic pole and the auxiliary magnetic pole described above. Since this resistance heater has a larger tip area than the main magnetic pole and the metal scatterer, the target area to be heated is wide and the temperature gradient is low. For this reason, the resistance heater can apply only heat that is preheated to the magnetic recording layer of the recording medium.
According to the magnetic recording head configured as described above, since the magnetic recording layer can be preheated by the resistance heater in advance, heat generation in the metal scatterer that generates near-field light can be reduced. Therefore, deterioration of the metal scatterer due to temperature rise, possibility of damage, and the like can be reduced, and durability can be improved.
JP 2004-158067 A JP-A-2005-4901 JP-A-2005-78689

However, the conventional magnetic recording head described above still has the following problems.
That is, in the magnetic recording heads described in Patent Documents 1 and 2, since the metal scatterer is provided outside the main pole so as to be located at the end in the scanning direction, information is stored in the magnetic recording layer. When recording, it is difficult to efficiently heat the position where the recording magnetic field is applied. That is, as the recording medium rotates, the magnetic recording layer moves in the order of the auxiliary magnetic pole, the magnetic pole, and the metal scatterer, so that the recording magnetic field is applied before being heated by the near-field light. For this reason, the peak position of the heating temperature due to the near-field light comes outside the area to which the recording magnetic field is applied, and the writing reliability is poor.
In particular, since the temperature gradient due to near-field light tends to be delayed with respect to the scanning direction of the recording medium, it is considered that the peak position of the heating temperature is shifted from directly below the metal scatterer. In consideration of this point, the peak position of the heating temperature is actually shifted in a direction further away from the recording magnetic field application region, and there is a high possibility that accurate writing cannot be performed.

  On the other hand, the magnetic recording head described in Patent Document 3 is provided with a preheating mechanism such as a resistance heater between the main magnetic pole and the auxiliary magnetic pole, so that the above-described problem of writing reliability is eliminated. However, on the other hand, since a preheating mechanism is further added as a component, there is a disadvantage that the configuration becomes more complicated and the size is increased.

  In the magnetic recording heads described in Patent Documents 1 to 3, when the recording track width is further reduced to achieve higher density recording, the distance between both magnetic poles is reduced or the size of the metal scatterer is reduced. It is necessary to further miniaturize the size of the component itself, for example, to design a smaller size. For this reason, the manufacturing is difficult and the cost is increased, and it cannot be easily performed.

  Further, in the conventional magnetic recording head, when a recording magnetic field is applied, not only the magnetic flux flows from the front end surface of the main magnetic pole facing the recording medium, but also the magnetic flux leaking from the side surface of the main magnetic pole flows to the recording medium. End up. Therefore, a part of the recording magnetic field flowing into the recording medium is not perpendicular to the surface of the magnetic field but is inclined. In other words, the magnetic field gradient was gradually reduced. As a result, part of the magnetic flux does not enter the magnetic recording layer of the recording medium straight, and it is difficult to efficiently perform magnetization reversal. Therefore, it has been difficult to cope with higher density recording.

  The present invention has been made in view of such circumstances, and its purpose is to easily manufacture at a low cost while achieving miniaturization, and to improve the writing reliability by efficiently generating near-field light. It is another object of the present invention to provide a near-field optical recording element, a near-field optical head, and an information recording / reproducing apparatus that can achieve higher density recording by reducing leakage magnetic flux.

The present invention provides the following means in order to solve the above problems.
The near-field optical recording element according to the present invention generates a near-field light from the introduced light flux, heats the magnetic recording medium rotating in a certain direction, and applies a perpendicular recording magnetic field to the magnetic recording medium. A near-field optical recording element that causes magnetization reversal and records information, and is arranged in parallel to a bottom surface on which the light beam is introduced and a position spaced apart from the bottom surface by a predetermined distance. A light-transmitting core formed in a quadrangular pyramid shape having an end face from which the near-field light is emitted and four side faces formed by connecting the bottom face and the apex of the end face, respectively, and a side face of the core Each of which is formed on two side surfaces facing each other and includes a main magnetic pole and an auxiliary magnetic pole for generating the recording magnetic field between them, and the auxiliary magnetic pole is formed on the core where the near-field light is generated. On the end side , And is characterized in that it comprises a protrusion protruding toward the one side said to be close to one side of the main magnetic pole.

In the near-field optical recording element according to the present invention, near-field light can be generated by using a core formed in a quadrangular pyramid shape, and information is written to a rotating magnetic recording medium. be able to.

When recording is performed here, a light beam is first introduced into the interior of the light transmissive core . The light beam introduced into the core leaks out from the end face as near-field light. The magnetic recording medium is locally heated by the near-field light, and the coercive force temporarily decreases.
Simultaneously with the introduction of the luminous flux, a recording magnetic field is generated between both the main magnetic pole and the auxiliary magnetic pole. That is, a recording magnetic field perpendicular to the magnetic recording medium is generated. Specifically, the magnetic flux generated from the main magnetic pole flows perpendicularly to the magnetic recording medium and returns to the auxiliary magnetic pole after passing through the magnetic recording medium. At this time, since the magnetic gap between the main magnetic pole and the auxiliary magnetic pole is a minute gap, the recording magnetic field acts locally on the magnetic recording medium. Thereby, the recording magnetic field can be applied to the local position of the magnetic recording medium whose coercive force is reduced by the near-field light. The direction of the recording magnetic field is reversed according to the information to be recorded.

  When the magnetic recording medium receives a recording magnetic field, the direction of magnetization is reversed in the vertical direction according to the direction of the recording magnetic field. As a result, information can be recorded. That is, information can be recorded by a near-field light assisted magnetic recording method in which near-field light and a recording magnetic field generated by both magnetic poles cooperate. In addition, since information can be recorded by the perpendicular magnetic recording method, it is difficult to receive the phenomenon of thermal fluctuation, and stable recording with high writing reliability can be performed.

In particular, since the near-field light can be generated between the main magnetic pole and the auxiliary magnetic pole, the peak position of the heating temperature by the near-field light can be set within the range where the recording magnetic field acts locally .
In addition, it is possible to achieve both near-field light generation and recording magnetic field generation simply by forming the main magnetic pole and auxiliary magnetic pole on the side surface of the core. Structure. Therefore, the configuration can be simplified, and the size can be reduced while facilitating the manufacture and reducing the cost.

  Further, when the recording magnetic field is generated, not only the magnetic flux flows from the front end surface of the main magnetic pole facing the surface of the magnetic recording medium, but also the magnetic flux leaks from the side surface of the main magnetic pole. However, since a part of the auxiliary magnetic pole is a protruding portion that protrudes toward the side surface of the main magnetic pole on the end surface side of the core as described above, the magnetic flux leaking from the side surface of the main magnetic pole flows to the magnetic recording medium. Before, it can flow into this protrusion. As a result, the leakage magnetic flux from the side surface is reduced, so that the magnetic flux can flow intensively from the front end surface of the main pole to the magnetic recording medium, and the magnetic field gradient can be made steeper than before. That is, the magnetic flux can flow more perpendicular to the magnetic recording medium. Therefore, the magnetization reversal of the magnetic recording medium can be performed more easily, and higher density recording can be achieved.

  In addition, since the main magnetic pole and the auxiliary magnetic pole are respectively formed on the side surfaces of the core, the track widths of both can be made the same. Therefore, when the magnetic flux emitted from the main magnetic pole returns to the auxiliary magnetic pole via the magnetic recording medium, the magnetic flux does not spread in the track width direction. Therefore, a sharp magnetization transition state can be formed, and track edge noise can be reduced as much as possible. In this respect as well, higher density recording can be achieved.

  As described above, the near-field optical recording element according to the present invention can be easily manufactured at a low cost while reducing the size, and can efficiently generate near-field light to improve writing reliability. can do. Further, the leakage magnetic flux from the side surface of the main magnetic pole can be reduced and the spread of the magnetic flux can be suppressed, so that higher density recording can be achieved.

  The near-field optical recording element according to the present invention includes an insulating layer formed on the other side surface of the main magnetic pole and a magnetic shield formed on the insulating layer in the near-field optical recording element of the present invention. And a layer.

In the near-field optical recording element according to the present invention, the magnetic shield layer is formed on the other side surface (the outer surface exposed to the outside rather than the inner surface on the core side) via the insulating layer. Thereby, when the recording magnetic field is generated, the magnetic flux leaking from the other side surface of the main pole can be blocked by the magnetic shield layer. That is, the magnetic flux leaking from the one side surface of the main magnetic pole can be absorbed by the protruding portion of the auxiliary magnetic pole, and the magnetic flux leaking from the other side surface of the main magnetic pole can be blocked by this magnetic shield.
Accordingly, the magnetic flux can flow more concentratedly from the front end surface of the main pole to the magnetic recording medium, and the magnetic field gradient can be further steepened. As a result, the magnetic flux can be made to flow more perpendicularly to the magnetic recording medium, and a much higher density recording can be achieved.

  Further, the near-field optical recording element according to the present invention is the near-field optical recording element according to the present invention, wherein the insulating layer is formed so as to surround all the side surfaces of the core, and the magnetic shield layer is It is characterized by being formed so as to further surround the periphery of the insulating layer that surrounds the periphery of all the side surfaces of the core.

In the near-field optical recording element according to the present invention, the insulating layer and the magnetic shield layer are formed so as to surround not only the other surface of the main pole but also the side surface of the core . In particular, since it is not necessary to form the insulating layer and the magnetic shield layer only on the target surface, it is easy to form the insulating layer and the magnetic shield layer. Therefore, the manufacturing can be facilitated.

  The near-field optical recording element according to the present invention is a metal that increases the light intensity of the near-field light between the main magnetic pole and the core in any of the near-field optical recording elements of the present invention. A film is formed.

  In the near-field optical recording element according to the present invention, when a light beam is introduced into the core, the light beam travels from the bottom surface side toward the end surface side, and leaks to the outside as near-field light from the end surface. At the same time, the light beam introduced into the core enters the metal film. When a light beam enters the metal film, surface plasmons are excited in the metal film. The excited surface plasmon propagates toward the end face through the interface between the metal film and the core while being enhanced by the resonance effect. And when it reaches the end face of the core, it becomes a near-field light with a strong light intensity and leaks outside. In particular, the near-field light propagated through the metal film has higher light intensity than the near-field light generated after being transmitted directly from the bottom surface toward the end surface, so that the light contributes by heating the magnetic recording medium.

  As described above, since the magnetic recording medium can be heated more efficiently by increasing the light intensity of the near-field light, the writing reliability can be further improved. In particular, since near-field light can be generated at the interface between the metal film and the core, it is not directly affected by the design size of each component. That is, near-field light having a high light intensity can be generated without being influenced by the physical design without making the size of the end face of the core smaller.

Further, the near-field optical recording element according to the present invention is sandwiched between the side surfaces of the core where the main magnetic pole and the auxiliary magnetic pole are respectively formed in the near-field optical recording element of the present invention. A metal film that increases the light intensity of the near-field light is formed on at least one side surface.

In the near-field optical recording element according to the present invention, the metal film for increasing the light intensity is formed on at least one of the side surfaces adjacent to the side surface on which the main magnetic pole and the auxiliary magnetic pole are formed. Therefore, this metal film is in a state parallel to the moving direction of the magnetic recording medium. When a light beam is introduced into the core, the light beam travels from the bottom surface side toward the end surface side, and leaks to the outside as near-field light from the end surface. At the same time, the light beam introduced into the core enters the metal film. When a light beam enters the metal film, surface plasmons are excited in the metal film. The excited surface plasmon propagates toward the end face through the interface between the metal film and the core while being enhanced by the resonance effect. And when it reaches the end face of the core, it becomes a near-field light with a strong light intensity and leaks outside. In particular, the near-field light propagated through the metal film has higher light intensity than the near-field light generated after being transmitted directly from the bottom surface toward the end surface, so that the light contributes by heating the magnetic recording medium.

  As described above, since the magnetic recording medium can be heated more efficiently by increasing the light intensity of the near-field light, the writing reliability can be further improved. In particular, since near-field light can be generated at the interface between the metal film and the core, it is not directly affected by the design size of each component. That is, near-field light having a high light intensity can be generated without being influenced by the physical design without making the size of the end face of the core smaller.

  Further, as described above, since the metal film is parallel to the moving direction of the magnetic recording medium, near-field light having a strong light intensity contributing to heating is generated in a line along the moving direction of the magnetic recording medium. Can do. That is, it can be generated in a line along the track direction of the magnetic recording medium. Therefore, information can be accurately recorded on a desired track without affecting the information recorded on the adjacent track.

The near-field optical recording element according to the present invention is characterized in that, in the near-field optical recording element of the present invention, the metal film is also formed on the main magnetic pole and the auxiliary magnetic pole. is there.
In the near-field optical recording element according to the present invention, since the metal film is formed not only on the side surface of the core but also on the main magnetic pole and the auxiliary magnetic pole, it is closer to the main magnetic pole and the auxiliary magnetic pole by the propagation of the surface plasmon. Field light can be generated. Therefore, the near-field light and the recording magnetic field can be more efficiently coordinated, and the writing reliability can be further improved.

The near-field optical recording element according to the present invention is the near-field optical recording element according to the present invention, wherein the main magnetic pole and the auxiliary magnetic pole are aligned in the rotation direction of the magnetic recording medium. It is.

Further, a near-field optical head according to the present invention is disposed with any one of the near-field optical recording elements of the present invention as described above in a state of being floated by a predetermined distance from the surface of the magnetic recording medium, and facing the surface of the magnetic recording medium. A slider having an opposing surface, a light beam introducing means for introducing the light beam into the core from a bottom surface side arranged in parallel to the end surface , a magnetic material, and the main magnetic pole and the auxiliary magnetic pole. A magnetic circuit to be connected and a coil that is supplied with a current modulated in accordance with the information and winds around the magnetic circuit around the magnetic circuit, and the core is disposed on the opposing surface of the slider. It is characterized in that the bottom surface is fixed in surface contact.

In the near-field optical head according to the present invention, the slider is disposed in a state where the slider floats a predetermined distance from the surface of the magnetic recording medium with the opposing surface facing the surface of the magnetic recording medium. The core of the near-field optical recording element is fixed with the bottom surface in surface contact with the opposing surface of the slider. As a result, the core is in a state of floating on the magnetic recording medium while the end face is opposed to the surface of the magnetic recording medium.
When recording is performed, the light beam is first introduced into the core from the bottom surface side by the light beam introducing means. At this time, unlike the conventional method of entering light, the light beam introducing means can easily and surely introduce the light beam in a substantially straight line from the upper surface side of the slider toward the end surface of the core, so that the near-field light is efficiently generated. be able to.
Simultaneously with the introduction of the luminous flux, a current modulated according to the information to be recorded is supplied to the coil. Then, due to the principle of the electromagnet, the current magnetic field generates a magnetic flux in the magnetic circuit, so that a recording magnetic field can be reliably generated between the main magnetic pole and the auxiliary magnetic pole.

  In particular, since the near-field optical recording element that can be easily manufactured at low cost while achieving miniaturization is provided, the near-field optical head itself can be reduced in size, cost, and manufacture. In addition, the near-field optical recording element that efficiently generates near-field light and has improved writing reliability. Similarly, the writing reliability of the near-field light head itself can be increased to improve the quality. it can. Furthermore, since the near-field optical element is designed to achieve high-density recording by reducing the leakage magnetic flux, the near-field optical head itself can be made to have high performance corresponding to high-density recording.

  Further, the near-field optical head according to the present invention is the near-field optical head according to the present invention, wherein the magnetic circuit has in part a vertical circuit portion along a direction perpendicular to the facing surface of the slider. Is formed in a state in which the periphery of the vertical circuit portion is spirally wound so as to spread along the facing surface.

In the near-field optical head according to the present invention, a part of the magnetic circuit connecting the main magnetic pole and the auxiliary magnetic pole is a vertical circuit portion along a direction perpendicular to the opposed surface of the slider. And the coil is formed in a state in which the periphery of the vertical circuit portion is spirally wound around the vertical circuit portion so as to spread along the opposing surface of the slider. That is, the coil is in a state parallel to the facing surface of the slider.
Therefore, even if the number of coils is increased. Since it does not affect the thickness of the slider, it is possible to increase the strength of the recording magnetic field while reducing the thickness. Further, since the coil can be produced on a horizontal plane instead of a vertical plane, it can be easily produced by a conventional method without using a special method. Therefore, the degree of freedom in design can be improved, such as making the coil thinner or increasing the number of windings. In addition, since the coil can be designed freely, it is easy to design the magnetic circuit freely, for example, by increasing the width. Thus, a magnetic circuit and a coil can be designed freely according to the situation, and a reliable electromagnet can be manufactured.

  An information recording / reproducing apparatus according to the present invention is movable in a direction parallel to the surface of the magnetic recording medium and the near-field optical head of the present invention, and is parallel to the surface of the magnetic recording medium and orthogonal to each other. A beam that supports the near-field optical head on the tip side while being rotatable about two axes, a light source that makes the light beam incident on the light beam introducing means, and a base end side of the beam. An actuator for moving the beam in a direction parallel to the surface of the magnetic recording medium, a rotation drive unit for rotating the magnetic recording medium in the fixed direction, and supplying the current to the coil, and the light source And a control unit for controlling the operation of the apparatus.

  In the information recording / reproducing apparatus according to the present invention, after the magnetic recording medium is rotated in a certain direction by the rotation driving unit, the beam is moved by the actuator to scan the near-field optical head. Then, the near-field optical head is arranged at a desired position on the magnetic recording medium. At this time, the near-field optical head is supported by the beam so that it can rotate about two axes parallel to the surface of the magnetic recording medium and orthogonal to each other, that is, can be twisted about the two axes. Yes. Therefore, even if waviness occurs in the magnetic recording medium, changes in wind pressure due to waviness can be absorbed by twisting, and the near-field optical head can be stably levitated.

Thereafter, the control unit activates the light source and simultaneously supplies a current modulated according to information to the coil. Thereby, the near-field light head can record information on the magnetic recording medium by cooperating the near-field light and the recording magnetic field.
In particular, since the near-field optical head having the above-mentioned near-field optical recording element is provided, it is possible to reduce the size and cost, and to improve the writing reliability and the quality. . Further, it is possible to achieve a high quality that can cope with high density recording.

  The near-field optical recording element according to the present invention can be easily manufactured at a low cost while reducing the size, and can efficiently generate near-field light to improve the writing reliability. Further, by reducing the leakage magnetic flux from the side surface of the main magnetic pole and suppressing the spread of the magnetic flux, further high density recording can be achieved.

  Further, according to the near-field optical head and the information recording / reproducing apparatus according to the present invention, since the near-field optical recording element described above is provided, it is possible to reduce the size, reduce the cost, and facilitate the manufacture. The reliability of writing is increased, and the quality can be improved. In addition, it is possible to achieve high performance corresponding to high density recording.

  Hereinafter, an embodiment of a near-field optical recording element, a near-field optical head, and an information recording / reproducing apparatus according to the present invention will be described with reference to FIGS. Note that the information recording / reproducing apparatus 1 of the present embodiment is an apparatus for writing on a disk (magnetic recording medium) D having a perpendicular recording layer d2 by a perpendicular recording method.

  As shown in FIG. 1, the information recording / reproducing apparatus 1 of this embodiment includes an optical near-field optical head 2 having a near-field optical recording element 20 described later, and an XY parallel to a disk surface (surface of a magnetic recording medium) D1. A beam 3 that supports the near-field optical head 2 on the tip side in a state that is movable around two axes (X-axis and Y-axis) that are parallel to the disk surface D1 and orthogonal to each other. An optical signal controller (light source) 5 for causing the light beam L to enter the optical waveguide 4 from the proximal end side of the waveguide 4 and an XY parallel to the disk surface D1 while supporting the proximal end side of the beam 3 An actuator 6 that scans and moves in a direction, a spindle motor (rotation drive unit) 7 that rotates the disk D in a certain direction, and a current modulated in accordance with information is supplied to a coil 24 that will be described later, and an optical signal. Con A control unit 8 for controlling the operation of the roller 5, and a housing 9 that houses the respective components therein.

  The housing 9 is made of a metal material such as aluminum and has a quadrangular shape when viewed from above, and a recess 9a for accommodating each component is formed inside. Further, a lid (not shown) is detachably fixed to the housing 9 so as to close the opening of the recess 9a. The spindle motor 7 is attached to substantially the center of the recess 9a, and the disc D is detachably fixed by fitting a center hole into the spindle motor 7. The actuator 6 is attached to the corner of the recess 9a. A carriage 11 is attached to the actuator 6 via a bearing 10, and a beam 3 is attached to the tip of the carriage 11. The carriage 11 and the beam 3 are both movable in the XY directions by driving the actuator 6.

  The carriage 11 and the beam 3 are retracted from the disk D by driving the actuator 6 when the rotation of the disk D is stopped. The near-field light head 2 and the beam 3 constitute a suspension 12. The optical signal controller 5 is mounted in the recess 9 a so as to be adjacent to the actuator 6. The control unit 8 is attached adjacent to the actuator 6.

  As shown in FIGS. 2 and 3, the near-field optical head 2 is disposed with the near-field optical recording element 20 in a state of floating by a predetermined distance H from the disk surface D1, and has a facing surface that faces the disk surface D1. A magnetic circuit that is formed of a magnetic material and connects a main magnetic pole 31 and an auxiliary magnetic pole 32, which will be described later, and a slider 21 having the slider 21, a light beam introducing means 22 for introducing a light beam L into the core 30 from the bottom surface 30a side of the core 30 described later. 23 and a coil 24 wound around the magnetic circuit 23 around the magnetic circuit 23.

The near-field light recording element 20 generates near-field light R from the introduced light beam L to heat the disk D, and causes a magnetization reversal by applying a perpendicular recording magnetic field to the disk D. Information is recorded.
That is, the near-field optical recording element 20 includes a core 30 that generates near-field light R, and a main magnetic pole 31 and an auxiliary magnetic pole 32 formed on the core 30, as shown in FIGS. In the present embodiment, a case where the protruding portion 32a of the auxiliary magnetic pole 32 is formed in a part of the end face 30b of the core 30 will be described as an example.

The core 30 is formed of a light-transmitting material such as quartz glass, and is formed in a quadrangular pyramid shape having a bottom surface 30a, an end surface 30b, and four side surfaces 30c. Specifically, the bottom surface 30a is formed in a square shape in plan view so as to have at least one set of two sides parallel to each other, arranged in a state parallel to the disk surface D1, and the light flux L is introduced from the bottom surface 30a. An end surface 30b formed in the same shape (square shape in plan view) with a small area and disposed at a predetermined distance from the bottom surface 30a, and four side surfaces 30c formed by connecting the bottom surface 30a and the apex of the end surface 30b, respectively. It is processed to have.
However, in the present embodiment, as described above, since the protruding portion 32a is formed so as to be partially embedded in the end surface 30b, the step portion 30d is formed on the end surface 30b.

  The bottom surface 30a and the end surface 30b of the core 30 are not limited to a square shape, and may be formed in a square shape in plan view. For example, it may be a plan view, a rectangular shape, a parallelogram shape, or a trapezoidal shape. Further, the bottom surface 30a and the end surface 30b may be formed in a square shape in plan view, and may not have the same shape.

  The end face 30b of the core 30 is formed to a size that generates near-field light R when the light beam L is introduced into the core 30. That is, the size of the end face 30b of the core 30 is designed so as to be much finer than the wavelength of the light beam L (for example, one side has a size of about several tens of nanometers), and transmits normal propagation light. However, the near-field light R can be leaked to the vicinity. Therefore, the four side surfaces 30c are in a slope state in which the distance from the side surface 30c facing each other gradually decreases toward the end surface 30b.

  Of the four side surfaces 30c of the core 30, on the two side surfaces 30c facing each other in a state of being aligned in the rotation direction of the disk D, the main magnetic pole 31 and the auxiliary magnetic pole 32 that generate the recording magnetic field therebetween. Is formed. These magnetic poles 31 and 32 are formed by a thin film deposition technique such as vapor deposition of a high saturation magnetic flux density (Bs) material (for example, CoNiFe alloy, CoFe alloy, etc.) having a high magnetic flux density.

Further, a part of the auxiliary magnetic pole 32 protrudes toward the one side surface so as to be close to one side surface (surface facing the auxiliary magnetic pole 32) of the main magnetic pole 31 on the end surface 30b side of the core 30. 32a. Moreover, the protruding portion 32a is formed so as to be buried in a part of the end face 30b. Therefore, the end surface 30b and the surface of the protrusion 32a are flush with each other. Due to the protrusion 32a, the exposed region of the end face 30b has a smaller size. Further, the interval (magnetic gap G) between the main magnetic pole 31 and the protruding portion 32a is very small (for example, several nm to several tens of nm).
The film thickness of the auxiliary magnetic pole 32 is adjusted so as to be larger than the film thickness of the main magnetic pole 31. In addition, the thickness of the protruding portion 32a is adjusted to be even thinner (for example, several tens to several hundreds nm).

  As shown in FIGS. 2 and 3, the core 30 configured in this manner is fixed in a state where the bottom surface 30 a is in surface contact with the facing surface 21 a of the slider 21. At this time, in the core 30, the main magnetic pole 31 and the auxiliary magnetic pole 32 are arranged along the moving direction of the disk D, and the main magnetic pole 31 is positioned on the moving direction side (traveling direction side) of the disk D relative to the auxiliary magnetic pole 32. After the orientation is adjusted, it is fixed.

  Similar to the core 30, the slider 21 is formed in a rectangular parallelepiped shape by a light transmissive material such as quartz glass. The slider 21 is supported so as to hang from the tip of the beam 3 via the gimbal portion 35 with the facing surface 21a facing the disk D side. The gimbal portion 35 is a component whose movement is restricted so as to be displaced only in the Z direction perpendicular to the disk surface D1, around the X axis, and around the Y axis. As a result, the slider 21 is rotatable about two axes (X axis, Y axis) that are parallel to the disk surface D1 and orthogonal to each other as described above.

  On the opposing surface 21 a of the slider 21, a convex portion 21 b is formed that generates a pressure for rising from the viscosity of the air flow generated by the rotating disk D. In this embodiment, the case where the two convex-shaped parts 21b extended along the longitudinal direction are formed so that it may rank with a rail shape is made into the example. However, the present invention is not limited to this case, and the slider 21 is optimally adjusted by adjusting the positive pressure for separating the slider 21 from the disk surface D1 and the negative pressure for attracting the slider 21 to the disk surface D1. Any irregular shape may be used as long as it is designed to float in a state. The surface of the convex portion 21b is a surface called ABS (Air Bearing Surface).

  The slider 21 receives a force that rises from the disk surface D1 by the two convex portions 21b, and also receives a force that is pressed by the beam 3 toward the disk surface D1. The slider 21 floats in a state where it is separated from the disk surface D1 by a predetermined distance H as described above due to the balance of both forces.

Further, as described above, since the core 30 is fixed to the facing surface 21a of the slider 21 with the bottom surface 30a being in surface contact, the end surface 30b of the core 30 is similarly the facing surface 21a of the slider 21 and the disk surface. It is in a parallel state with respect to D1. At this time, the height of the core 30 is set so that the height of the end face 30b is the same as the height of the convex portion 21b.
Note that the core 30 and the slider 21 may be separately manufactured and then fixed to each other, or may be manufactured integrally from quartz glass or the like. In particular, it is more preferable to manufacture them integrally because the manufacturing process can be simplified and the manufacturing time can be shortened.

In addition, a lens 36 is formed on the upper surface of the slider 21 at a position that is directly above the core 30. This lens 36 is, for example, an aspherical microlens formed by etching using a gray scale mask. Further, an optical waveguide 4 such as an optical fiber is attached to the upper surface of the slider 21. The optical waveguide 4 has a mirror surface 4 a with the tip cut at approximately 45 degrees, and the mounting position is adjusted so that the mirror surface 4 a is positioned directly above the lens 36. The optical waveguide 4 is drawn out and connected to the optical signal controller 5 via the beam 3 and the carriage 11.
As a result, the optical waveguide 4 can guide the light beam L incident from the optical signal controller 5 to the tip side, reflect the light beam L by the mirror surface 4a, change the direction, and then emit it to the lens 36. The emitted light beam L is focused by the lens 36, then passes through the slider 21 and is introduced into the bottom surface 30 a of the core 30. That is, the optical waveguide 4 and the lens 36 constitute the light flux introducing means 22 described above.

  As shown in FIG. 3, the magnetic circuit 23 is formed by patterning in the slider 21 with a magnetic material. Both ends of the magnetic circuit 23 are connected to the main magnetic pole 31 and the auxiliary magnetic pole 32, respectively, and as shown in FIG. 7, a portion corresponding to the approximate middle of the circuit is in a direction perpendicular to the facing surface 21a of the slider 21. The vertical circuit portion 23a is bent along.

  The coil 24 is formed along the opposing surface 21 a of the slider 21 in a state in which the periphery of the above-described vertical circuit portion 23 a of the magnetic circuit 23 is spirally wound. At this time, the coil 24 is insulated between adjacent wires and the magnetic circuit 23 so as not to be short-circuited. The coil 24 is electrically connected to the control unit 8 via the beam 3 and the carriage 11, and a current modulated according to information is supplied from the control unit 8. That is, the magnetic circuit 23 and the coil 24 constitute an electromagnet as a whole.

  Further, as shown in FIGS. 2 and 3, a magnetoresistive film 37 whose electric resistance is converted according to the magnitude of the magnetic field leaking from the perpendicular recording layer d2 of the disk D is provided on the front end surface of the slider 21. Is formed. A bias current is supplied to the magnetoresistive effect film 37 from the control unit 8 via a lead film (not shown). As a result, the control unit 8 can detect a change in the magnetic field leaking from the disk D as a change in voltage, and reproduces a signal from the change in voltage. That is, the magnetoresistive film 37 functions as a reproducing element.

The disk D of the present embodiment is a perpendicular structure composed of at least two layers: a perpendicular recording layer d2 having an easy axis in the direction perpendicular to the disk surface D1, and a soft magnetic layer d3 made of a high magnetic permeability material. A double layer disc D is used. As such a disk D, for example, as shown in FIG. 2, a soft magnetic layer d3, an intermediate layer d4, a perpendicular recording layer d2, a protective layer d5, and a lubricating layer d6 are sequentially formed on a substrate d1. Use the film.
Examples of the substrate d1 include an aluminum substrate and a glass substrate. The soft magnetic layer d3 is a high magnetic permeability layer. The intermediate layer d4 is a crystal control layer of the perpendicular recording layer d2. The perpendicular recording layer d2 is a perpendicular anisotropic magnetic layer, and for example, a CoCrPt alloy is used. The protective layer d5 is for protecting the perpendicular recording layer d2, and for example, a DLC (Diamond Like Carbon) film is used. For the lubrication layer d6, for example, a fluorine-based liquid lubricant is used.

  Here, a manufacturing method of the near-field optical recording element 20 of the present embodiment will be described below with reference to FIG. Here, the case where the slider 21 and the core 30 are integrally manufactured from one substrate T will be described as an example. However, the manufacturing method of the core 30 will be mainly described. Therefore, the convex portion 21b, the lens 36, and the like may be appropriately formed during the process described below. In FIG. 8, sectional views from different viewpoints are shown on the left side and the right side, respectively. The left cross-sectional view shows a cross-sectional view along the plane A shown in FIG. Further, the left sectional view shows a sectional view along a plane B shown in FIG.

First, after preparing a substrate T of quartz glass or the like, as shown in FIG. 8A, an etching mask M1 for forming a step portion 30d of the end face 30b on the substrate T is patterned only in a predetermined region. The etching mask M1 is a photoresist thin film processed by a photolithography technique.
Next, the surface of the substrate T is etched using the etching mask M1 as a mask. The etching process may be wet etching or dry etching. Then, by removing the etching mask M1, a step portion 30d can be formed on the substrate T as shown in FIG. Note that the etching is performed so that the depth of the stepped portion 30d falls within the range of several tens of nm to several hundreds of nm.

Next, as shown in FIG. 8C, the etching mask M2 for forming the end face 30b on the substrate T is patterned only in a predetermined region including a part of the step portion 30d. At this time, the etching mask M2 is substantially square when viewed from above.
Next, the substrate T is etched using the etching mask M2 as a mask. At this time, isotropic etching is performed although either dry etching or wet etching may be performed. Thereby, the etchant also enters a part of the surface of the substrate T hidden under the etching mask M2, and the quadrangular pyramid shaped core 30 can be formed. When quartz glass is used as the substrate T, isotropic wet etching with a hydrofluoric acid aqueous solution is preferable.

  Subsequently, after removing the etching mask M2, as shown in FIG. 8D, a metal film M3 for forming the main magnetic pole 31 and the auxiliary magnetic pole 32 is formed on the surface of the substrate T by sputtering or the like. As a result, the metal film M3 is formed on all of the four side surfaces 30c and the end surface 30b of the core 30.

Next, as shown in FIG. 8E, an etching mask M4 is formed on a part of the formed metal film M3 using a film forming method having directivity such as a spray coating method. Specifically, on the two side surfaces 30c on which the main magnetic pole 31 and the auxiliary magnetic pole 32 will be formed later, on one of the two side surfaces 30c sandwiched between these two side surfaces 30c, and the end surface An etching mask M4 is formed on each of the metal films M3 formed on 30b.
Next, the metal film M3 is etched using the etching mask M4 as a mask. Then, the state shown in FIG. 8F is obtained by removing the etching mask M3.

  Next, an etching mask (not shown) is formed again on a part of the remaining metal film M3 by using a directional film forming method such as a spray coating method. Specifically, an etching mask is formed on the metal film M3 formed on the two side surfaces 30c and the end surface 30b where the main magnetic pole 31 and the auxiliary magnetic pole 32 will be formed later. Then, the metal film M3 is etched again using this etching mask as a mask. Then, the state shown in FIG. 8G is obtained by removing the etching mask.

  Finally, polishing is performed from above the end face 30b of the core 30 substantially in parallel with the end face 30b. As a result, as shown in FIG. 8H, the core 30 on which the main magnetic pole 31 and the auxiliary magnetic pole 32 having the protruding portion 32 a are formed can be manufactured in a state of being fixed to the slider 21. Moreover, since the stepped portion 30d is formed, the protruding portion 32a can be formed in a state of being embedded in the end surface 30b, and the end surface 30b and the surface of the protruding portion 32a can be flush with each other.

As described above, the core 30, the main magnetic pole 31, the auxiliary magnetic pole 32, and the slider 21 can be easily manufactured integrally using a commonly used photolithography technique and semiconductor processing techniques such as etching. Therefore, it can manufacture efficiently and can suppress manufacturing cost.
Further, since the protruding portion 32a can be formed only by forming the step portion 30d by etching and forming the metal film M3 thereon, the thickness of the protruding portion 32a can be easily reduced. In addition, the advantage of making the protrusion part 32a thin is demonstrated later.

Next, a case where various kinds of information is recorded / reproduced on / from the disk D by the information recording / reproducing apparatus 1 configured as above will be described below.
First, the spindle motor 7 is driven to rotate the disk D in a certain direction. Next, the actuator 6 is operated to scan the beam 3 in the XY directions via the carriage 11. As a result, the near-field optical head 2 can be positioned at a desired position on the disk D as shown in FIG. At this time, the near-field light head 2 receives a force that rises by the two convex portions 21 b formed on the opposing surface 21 a of the slider 21, and is pressed against the disk D by a predetermined force by the beam 3 or the like. The near-field optical head 2 floats to a position separated by a predetermined distance H from the disk D as shown in FIG.

  Further, even if the near-field optical head 2 receives wind pressure generated due to the undulation of the disk D, the gimbal portion 35 can be displaced about the Z direction and the XY axis. It is possible to absorb wind pressure caused by. Therefore, the near-field light head 2 can be floated in a stable state.

Here, when recording information, the control unit 8 operates the optical signal controller 5 and supplies a current modulated according to the information to the coil 24.
In response to an instruction from the control unit 8, the optical signal controller 5 causes the light beam L to enter from the proximal end side of the optical waveguide 4. The incident light beam L travels toward the front end side in the optical waveguide 4 and is emitted from the optical waveguide 4 while changing its direction by approximately 90 degrees on the mirror surface 4a as shown in FIG. The emitted light beam L is transmitted through the slider 21 while being focused by the lens 36, and enters the core 30 of the near-field optical recording element 20 provided almost directly below the lens 36 from the bottom surface 30a side. That is, the light beam L is introduced from the upper surface side of the slider 21 toward the core 30 in a substantially straight line by the light beam introducing means 22.

The light beam introduced into the core 30 travels from the bottom surface 30a side toward the end surface 30b side, and leaks to the outside as near-field light R from the end surface 30b facing the disk surface D1, as shown in FIG. Due to the near-field light R, the disk D is locally heated and the coercivity is temporarily reduced.
Both magnetic poles 31 and 32 are preferably formed from a light-impermeable material. By doing so, it is possible to prevent the light flux from leaking to the outside of the core 30 from the side surface 30c where the magnetic poles 31 and 32 are formed.

  On the other hand, when a current is supplied to the coil 24 by the control unit 8, a current magnetic field generates a magnetic flux in the magnetic circuit 23 according to the principle of an electromagnet, and therefore recording between the magnetic poles 31 and 32 in a direction perpendicular to the disk D is performed. Magnetic field is generated. Then, the magnetic flux generated from the main magnetic pole 31 side passes straight through the perpendicular recording layer d2 of the disk D and reaches the soft magnetic layer d3 as shown in FIG. As a result, recording can be performed in a state where the magnetization of the perpendicular recording layer d2 is directed perpendicular to the disk surface D1. The magnetic flux reaching the soft magnetic layer d3 returns to the auxiliary magnetic pole 32 via the soft magnetic layer d3. At this time, when returning to the auxiliary magnetic pole 32, the magnetization direction is not affected. This is because the area of the auxiliary magnetic pole 32 facing the disk surface D1 is larger than that of the main magnetic pole 31, so that the magnetic flux density is large and a force sufficient to reverse the magnetization does not occur. That is, recording can be performed only on the main magnetic pole 31 side.

  As a result, information can be recorded by the near-field light assisted magnetic recording method in which the near-field light R and the recording magnetic field generated by the magnetic poles 31 and 32 cooperate. Moreover, since the recording is performed by the vertical recording method, it is difficult to be affected by the thermal fluctuation phenomenon and the like, and stable recording can be performed. Therefore, writing reliability can be improved.

  Next, when reproducing information recorded on the disk D, the magnetoresistive film 37 formed on the tip surface of the slider 21 receives a magnetic field leaking from the perpendicular recording layer d2 of the disk D. The electric resistance changes depending on the size. Therefore, the voltage of the magnetoresistive film 37 changes. As a result, the control unit 8 can detect a change in the magnetic field leaking from the disk D as a change in voltage. And the control part 8 can reproduce | regenerate information by reproducing | regenerating a signal from the change of this voltage.

In particular, according to the information recording / reproducing apparatus 1 of the present embodiment, unlike the conventional method of entering light, the light beam L is easily and surely introduced in a substantially straight line from the upper surface side of the slider 21 toward the end surface 30b of the core 30. Therefore, the near-field light R can be generated efficiently.
In addition, the generation of the near-field light R and the generation of the recording magnetic field can be achieved simultaneously by fixing the core 30 to the facing surface 21a of the slider 21 and forming both magnetic poles 31 and 32 on the side surface 30c of the core 30. Therefore, a simple structure can be achieved without a complicated configuration as in the prior art. Therefore, the configuration can be simplified and the size can be reduced.

Further, since the magnetic cap G between the main magnetic pole 31 and the auxiliary magnetic pole 32 is a minute gap, the recording magnetic field acts locally on the disk D. Thereby, the recording magnetic field can be applied to the local position where the coercive force is reduced by the near-field light R.
In particular, since the near-field light R can be generated between the main magnetic pole 31 and the auxiliary magnetic pole 32, the peak position of the heating temperature by the near-field light R can be set within the range where the recording magnetic field acts locally. it can. Moreover, even if the temperature gradient of the heating by the near-field light R is delayed with respect to the moving direction of the disk D, the dotted line indicates the generation region of the near-field light R, and the solid line indicates the heating temperature distribution by the near-field light R. The two-dot chain line shows the magnetic field intensity distribution generated from both magnetic poles 31 and 32), and the peak position of the heating temperature can be brought close to the main magnetic pole 31. Therefore, the writable area A is substantially directly below the first main magnetic pole 31, and recording can be reliably performed at a local position of the disk D.

  In addition, since only the main magnetic pole 31 and the auxiliary magnetic pole 32 are formed on the side surface 30c of the core 30, the generation of the near-field light R and the generation of the recording magnetic field can be achieved at the same time. Can be simple configuration. Therefore, the configuration can be simplified and the size can be reduced. Further, as described in the manufacturing method described above, manufacturing can be performed easily and at low cost.

  Further, when the recording magnetic field is generated, not only the magnetic flux flows from the front end surface of the main magnetic pole 31 facing the surface of the disk D, but also the magnetic flux leaks from the side surface 30 c of the main magnetic pole 31. However, as shown in FIG. 9, since a part of the auxiliary magnetic pole 32 is a protruding portion 32a, the magnetic flux leaking from the side surface 30c of the main magnetic pole 31 flows into the protruding portion 32a before flowing into the disk D. Can be made. As a result, the leakage magnetic flux from the side surface 30c of the main magnetic pole 31 is reduced, so that the magnetic flux can flow intensively from the front end surface of the main magnetic pole 31 to the disk D, and the magnetic field gradient can be made steeper than before. . That is, the magnetic flux can flow more perpendicularly to the disk D. Therefore, the magnetization reversal of the disk D can be performed more easily, and higher density recording can be achieved.

  Moreover, it is preferable to make the thickness of the protrusion part 32a thin from several micrometers to several tens of micrometers. By reducing the thickness of the protrusion 32a, it is possible to prevent the magnetic flux from flowing excessively from the main magnetic pole 31 toward the protrusion 32a. If the thickness of the protrusion 32a is increased, in addition to the magnetic flux leaking from the side surface 30c of the main magnetic pole 31, there is a possibility that the magnetic flux flowing from the front end surface to the disk D (magnetic flux necessary for contributing to information recording) may flow. is there. Therefore, it is preferable to make the protrusion 32a as thin as possible. In particular, as described in the manufacturing method described above, since the thin protrusion 32a can be easily manufactured, only the magnetic flux leaking from the side surface 30c can be obtained without affecting the magnetic flux required for writing information. Can be absorbed.

  Also, since the main magnetic pole 31 and the auxiliary magnetic pole 32 are respectively formed on the side surface 30c of the core 30, as shown in FIG. 10, the track widths (W1, W2) of both can be made the same width. Therefore, when the magnetic flux emitted from the main magnetic pole 31 returns to the auxiliary magnetic pole 32 via the disk D, the magnetic flux does not spread in the track width direction. Therefore, a sharp magnetization transition state can be formed, and track edge noise can be reduced as much as possible. In this respect as well, higher density recording can be achieved.

  Further, as shown in FIG. 7, the coil 24 is formed in a state in which the periphery of the vertical circuit portion 23 a of the magnetic circuit 23 is spirally wound, and is parallel to the facing surface 21 a of the slider 21. Therefore, even if the number of windings of the coil 24 is increased, the thickness of the slider 21 is not affected. Therefore, the strength of the recording magnetic field can be increased while reducing the thickness. Further, since the coil 24 can be produced on a horizontal plane instead of a vertical plane, it can be easily produced by a conventional method without using a special method. Therefore, the degree of freedom in design can be improved, such as making the coil 24 thinner or increasing the number of windings. In addition, since the coil 24 can be designed freely, the magnetic circuit 23 can be designed easily by increasing the width. Thus, the magnetic circuit 23 and the coil 24 can be freely designed according to the situation, and a reliable electromagnet can be manufactured.

As described above, according to the near-field optical recording element 20 of the present embodiment, it can be easily manufactured at a low cost while reducing the size, and the near-field light R is efficiently generated to improve the writing reliability. Can be improved. Further, the leakage magnetic flux from the side surface 30c of the main magnetic pole 31 can be reduced and the spread of the magnetic flux can be suppressed, so that further high density recording can be achieved.
According to the near-field optical head 2 and the information recording / reproducing apparatus 1 of the present embodiment, since the near-field optical recording element 20 described above is provided, it is possible to achieve downsizing, cost reduction, and ease of manufacture. Therefore, the writing reliability is improved and the quality can be improved. In addition, it is possible to achieve high performance corresponding to high density recording.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the shape of the bottom surface 30a and the end surface 30b of the core 30 is a square shape when viewed from above, but is not limited to this case. For example, as shown in FIG. 11, it may be formed in a parallelogram shape in a top view, or in a trapezoid shape in a top view as shown in FIG. Furthermore, as shown in FIG. 13, the four sides may be formed in a quadrangular shape in a top view in which none of the four sides is in a parallel relationship. In any case, the core 30 may be formed in a quadrangular pyramid shape.

  Moreover, in the said embodiment, although the protrusion part 32a was formed so that it might be embedded in a part of end surface 30b of the core 30, it is not restricted to this case. For example, as shown in FIGS. 14 and 15, the protruding portion 32 a may be formed so as to overlap the end surface 30 b of the core 30. In this case, the main magnetic pole 31 may be formed so as to slightly protrude toward the end face 30 b of the core 30. By doing so, the protrusion 32 a can be brought close to the side surface 30 c of the main magnetic pole 31 on the end surface 30 b side of the core 30. Even in this case, the same effects as those of the above-described embodiment can be achieved. In particular, in this case, it is not necessary to form the step portion 30d on the end face 30b, so that the manufacture becomes easier.

In the above embodiment, as shown in FIGS. 16 and 17, the insulating layer 40 is formed on the other side surface of the main pole 31 (the outer surface exposed to the outside rather than the inner surface on the core 30 side), A magnetic shield layer 41 (for example, made of NiFe or the like) may be formed on the insulating layer 40.
By doing so, the magnetic shield layer 41 can block the magnetic flux leaking from the other side surface of the main pole 31 when the recording magnetic field is generated. That is, the magnetic flux leaking from one side surface of the main magnetic pole 31 can be absorbed by the protrusion 32 a of the auxiliary magnetic pole 32, and the magnetic flux leaking from the other side surface of the main magnetic pole 31 can be blocked by the magnetic shield layer 41. . Therefore, the magnetic flux can flow more concentratedly from the front end surface of the main magnetic pole 31 to the disk D, and the magnetic field gradient can be further steepened. As a result, the magnetic flux can flow more perpendicularly to the disk D, and a much higher density recording can be achieved.

When forming the insulating layer 40 and the magnetic shield layer 41, as shown in FIG. 18, the insulating layer 40 is formed so as to surround the entire side surface 30c of the core 30, and the insulating layer 40 of the core 30 is also formed. The magnetic shield layer 41 may be formed so as to further surround the periphery. That is, the insulating layer 40 and the magnetic shield layer 41 are respectively formed so as to surround the four side surfaces 30c except for the end surface 30b and the bottom surface 30a of the core 30.
Even in this case, the same operational effects as those described above can be achieved. In addition, since it is not necessary to form the insulating layer 40 and the magnetic shield layer 41 only on the target surface, the insulating layer 40 and the magnetic shield layer 41 can be easily formed. Therefore, the manufacturing can be facilitated.

As shown in FIGS. 19 and 20, a metal film 45 that increases the light intensity of the near-field light R may be formed between the main magnetic pole 31 and the core 30. The metal film 45 is, for example, an Au film, and is formed on the side surface 30c of the core 30 by vapor deposition or the like.
When the metal film 45 is formed in this way, when the light beam L is introduced into the core 30, the light beam L travels from the bottom surface 30a side to the end surface 30b side and from the end surface 30b to the near-field light R. And leak out. At the same time, the light beam L introduced into the core 30 also enters the metal film 45. When the light beam L is incident on the metal film 45, surface plasmons are excited on the metal film 45. The excited surface plasmon propagates toward the end face 30b through the interface between the metal film 45 and the core 30 while being enhanced by the resonance effect. Then, when reaching the end face 30b of the core 30, the near-field light R having a high light intensity leaks to the outside. In particular, the near-field light R propagated through the metal film 45 has a higher light intensity than the near-field light R generated after being transmitted directly from the bottom surface 30a toward the end surface 30b. It becomes.

By forming the metal film 45 as described above, the optical intensity of the near-field light R can be increased and the disk D can be heated more efficiently, so that the writing reliability can be further improved. In particular, since the near-field light R can be generated at the interface between the metal film 45 and the core 30, the design size itself of each component is not affected. That is, the near-field light R having a high light intensity can be generated without being affected by the physical design without making the size of the end face 30b of the core 30 finer. .
Here, the case where both the metal film 45 and the magnetic shield layer 41 are formed simultaneously is taken as an example, but only the metal film 45 may be formed. However, it is preferable to form the metal film 45 and the magnetic shield layer 41 simultaneously.

Further, when the metal film 45 is formed, the metal film 45 is formed between the main magnetic pole 31 and the core 30 in FIGS. 19 and 20, but the present invention is not limited to this, and as shown in FIGS. 21 and 22, the main magnetic pole 31 is formed. Alternatively, the metal film 45 may be formed on one side surface 30c sandwiched between the side surfaces 30c on which the auxiliary magnetic poles 32 are formed. Even in this case, the same effects can be achieved.
In addition, since the metal film 45 is parallel to the moving direction of the disk D, the near-field light R having a high light intensity contributing to heating is generated in a line along the moving direction of the disk D. Can do. That is, it can be generated in a line along the track direction of the disk D. Specifically, as shown in FIG. 23, even if the width of the end face 30b of the core 30 is W1 (W2), the line-shaped near-field light R having a high light intensity generated by the metal film 45 is about W3. It becomes the width of. Therefore, the recording track width can be further reduced, and information can be accurately recorded on a desired track without affecting the information recorded on the adjacent track.

  21 and 22, the metal film 45 is formed only on the side surface 30c of the core 30. However, the present invention is not limited to this, and the metal film 45 is formed on the main magnetic pole 31 and the auxiliary magnetic pole 32 as shown in FIG. It may be formed so as to cover. By doing so, the near-field light R can be generated closer to the main magnetic pole 31 and the auxiliary magnetic pole 32 by the propagation of the surface plasmon. Therefore, it becomes easier to superimpose the recording magnetic field and the peak position of the heating temperature by the near-field light R in a spot manner. Therefore, the near-field light R and the recording magnetic field can be more efficiently coordinated, and the writing reliability can be further improved.

Further, as shown in FIG. 25, the metal films 45 may be formed on the two side surfaces 30c sandwiched between the side surfaces 30c on which the main magnetic pole 31 and the auxiliary magnetic pole 32 are respectively formed. Furthermore, as shown in FIG. 26, a metal film 45 may be formed so as to surround the periphery of the core 30. Even in these cases, the same effects can be obtained.
In addition, when the metal film 45 is formed on the two side surfaces 30c of the core 30, as shown in FIG. 27, the insulating layer 40 and the magnetic shield layer 41 may be formed simultaneously so as to surround the core 30. Absent. In this case, the effect of the metal film 45 and the effect of the magnetic shield layer 41 can be achieved simultaneously.

In the above embodiment, the light signal controller 5 is mounted in the housing 9 and the light beam L is incident from the proximal end side of the optical waveguide 4 constituting the light beam introducing means 22, thereby guiding the light beam L to the core 30. Although the configuration is adopted, it is not limited to this case.
For example, as shown in FIG. 28, the light flux introducing means 22 may be configured by only the lens 36, and the optical signal controller 5 may be provided between the lens 36 and the gimbal portion 35. In this case, the optical signal controller 5 and the control unit 8 may be electrically connected by arranging wirings or the like along the beam 3. Even in this case, the light beam L can be reliably incident on the light beam introducing means 22 from the optical signal controller 5. In particular, since the light beam L can be directly incident on the lens 36, the near-field light R can be generated more efficiently.

It is a block diagram which shows one Embodiment of the information recording / reproducing apparatus provided with the near-field optical head which has a near-field optical recording element based on this invention. It is an expanded sectional view of the near-field optical head shown in FIG. FIG. 3 is a diagram of the near-field optical head shown in FIG. 2 viewed from the disk surface side. FIG. 4 is a perspective view of a near-field optical recording element of the near-field optical head shown in FIG. 3. It is a side view of the near-field optical recording element shown in FIG. FIG. 5 is an enlarged view of the end face side of the near-field optical recording element shown in FIG. 4. It is sectional drawing which shows the attachment positional relationship of the coil and magnetic circuit of the near-field optical head shown in FIG. FIG. 5 is a process diagram for manufacturing the near-field optical recording element shown in FIG. 4, wherein the left side is a cross-sectional view along the plane A shown in FIG. 4 and the right side is a cross-sectional view along the plane B shown in FIG. 4. It is. FIG. 3 is a diagram showing a state during recording on a disk by the near-field optical head shown in FIG. 2, and is an enlarged cross-sectional view centering on a core. It is the figure which showed the relationship between the near field light at the time of recording on a disc, and a magnetic field. It is a figure which shows the modification of the near-field optical recording element which concerns on this invention, Comprising: It is the enlarged view which looked at the core in which the bottom face and the end surface were formed in the shape of a parallelogram from the end surface side. It is a figure which shows the modification of the near-field optical recording element which concerns on this invention, Comprising: It is the enlarged view which looked at the core in which the bottom face and the end surface were formed in trapezoid shape from the end surface side. It is a figure which shows the modification of the near-field optical recording element which concerns on this invention, Comprising: The enlarged view which looked at the core by which the bottom face and the end surface were formed in quadrilateral shape so that none of four sides became parallel relation from the end surface side It is. It is a figure which shows the modification of the near-field optical recording element which concerns on this invention, Comprising: It is a perspective view of the near-field optical recording element formed so that the protrusion part of an auxiliary | assistant magnetic pole may cover the end surface of a core. It is a side view of the near-field optical recording element shown in FIG. It is a figure which shows the modification of the near field optical recording element which concerns on this invention, Comprising: It is a perspective view of the near field optical recording element by which the insulating layer and the magnetic-shielding layer are formed on the main pole. FIG. 17 is a side view of the near-field optical recording element shown in FIG. 16. It is a figure which shows the modification of the near-field optical recording element which concerns on this invention, Comprising: It is a perspective view of the near-field optical recording element in which the insulating layer and the magnetic-shielding layer are formed so that the circumference | surroundings of a core may be enclosed. FIG. 6 is a diagram showing a modification of the near-field optical recording element according to the present invention, in which an insulating layer and a magnetic shield layer are formed on the main pole, and a metal film is formed between the main pole and the core. It is a perspective view of a near-field optical recording element. FIG. 20 is a side view of the near-field optical recording element shown in FIG. 19. FIG. 10 is a diagram showing a modification of the near-field optical recording element according to the present invention, and a near-field light in which a metal film is formed on one side surface sandwiched between side surfaces on which a main magnetic pole and an auxiliary magnetic pole are formed It is a perspective view of a recording element. FIG. 22 is a side view of the near-field optical recording element shown in FIG. 21. It is the figure which showed the relationship between near-field light and a magnetic field at the time of recording on a disc by the near-field light recording element shown in FIG. It is a figure which shows the modification of the near-field optical recording element shown in FIG. 21, Comprising: The enlarged view which looked at the near-field optical recording element formed so that a metal film might cover the main magnetic pole and the auxiliary | assistant magnetic pole from the end surface side of the core It is. It is a figure which shows the modification of the near field optical recording element which concerns on this invention, Comprising: The near field light by which the metal film is formed on two side surfaces pinched | interposed into the side surface in which the main magnetic pole and the auxiliary | assistant magnetic pole are formed It is a perspective view of a recording element. It is a figure which shows the modification of the near field optical recording element which concerns on this invention, Comprising: It is a perspective view of the near field optical recording element in which the metal film is formed so that the circumference | surroundings of a core may be enclosed. FIG. 7 is a diagram showing a modification of the near-field optical recording element according to the present invention, in which a metal film is formed on two side surfaces sandwiched between side surfaces on which a main magnetic pole and an auxiliary magnetic pole are formed, and a metal film FIG. 3 is a perspective view of a near-field optical recording element in which an insulating layer and a magnetic shield layer are formed so as to surround the periphery of a core. It is a figure which shows the modification of the near-field optical head which concerns on this invention, Comprising: It is sectional drawing of the near-field optical head provided with the optical signal controller between the lens and the gimbal part.

Explanation of symbols

D disk (magnetic recording medium)
D1 disk surface (surface of magnetic recording medium)
L Light flux R Near-field light 1 Information recording / reproducing apparatus 2 Near-field light head 3 Beam 5 Light source (optical signal controller)
6 Actuator 7 Spindle motor (rotary drive)
8 Control unit 20 Near-field optical recording element 21 Slider 22 Light flux introducing means
DESCRIPTION OF SYMBOLS 23 Magnetic circuit 23a Vertical circuit part 24 Coil 30 Core 30a Core bottom face 30b Core end face 30c Core side face 31 Main magnetic pole 32 Auxiliary magnetic pole 32a Protrusion part 40 Insulating layer 41 Magnetic shield layer 45 Metal film

Claims (10)

The near-field light is generated from the introduced light beam to heat the magnetic recording medium that rotates in a certain direction, and the perpendicular magnetic field is applied to the magnetic recording medium to cause magnetization reversal and record information. A near-field optical recording element comprising:
The bottom surface into which the light beam is introduced is connected in parallel to a position spaced apart from the bottom surface by a predetermined distance, and the end surface from which the near-field light is emitted when the light beam is introduced is connected to the bottom surface and the vertex of the end surface, respectively. A light-transmitting core formed in a quadrangular pyramid shape having four side surfaces formed by :
A main magnetic pole and an auxiliary magnetic pole that are respectively formed on two side surfaces facing each other among the side surfaces of the core, and that generate the recording magnetic field between them,
The auxiliary magnetic pole includes a protruding portion that protrudes toward the one side surface so as to be close to one side surface of the main magnetic pole on the end surface side of the core where the near-field light is generated. Near-field optical recording element. The near-field optical recording element according to claim 1,
An insulating layer formed on the other side surface of the main pole;
A near-field optical recording element comprising: a magnetic shield layer formed on the insulating layer. The near-field optical recording element according to claim 2,
The insulating layer is formed so as to surround all the side surfaces of the core,
The near-field optical recording element according to claim 1, wherein the magnetic shield layer is formed so as to further surround the periphery of the insulating layer surrounding all sides of the core. The near-field optical recording element according to any one of claims 1 to 3,
A near-field optical recording element, wherein a metal film for increasing the light intensity of the near-field light is formed between the main magnetic pole and the core. The near-field optical recording element according to any one of claims 1 to 3,
A metal film for increasing the light intensity of the near-field light is formed on at least one side surface sandwiched between the side surfaces on which the main magnetic pole and the auxiliary magnetic pole are respectively formed among the side surfaces of the core. A near-field optical recording element characterized. The near-field optical recording element according to claim 5,
The near-field optical recording element, wherein the metal film is also formed on the main magnetic pole and the auxiliary magnetic pole. The near-field optical recording element according to any one of claims 1 to 6 ,
The near-field optical recording element, wherein the main magnetic pole and the auxiliary magnetic pole are arranged in a rotation direction of the magnetic recording medium. The near-field optical recording element according to any one of claims 1 to 7 ,
A slider disposed in a state of floating a predetermined distance from the surface of the magnetic recording medium and having a facing surface facing the surface of the magnetic recording medium;
A light beam introducing means for introducing the light beam into the core from the bottom surface side arranged in parallel to the end surface;
A magnetic circuit formed of a magnetic material and connecting the main magnetic pole and the auxiliary magnetic pole;
A current that is modulated in accordance with the information is provided, and a coil that winds around the magnetic circuit around the magnetic circuit;
The near-field optical head according to claim 1, wherein the core is fixed in a state where the bottom surface is in surface contact with a facing surface of the slider. The near-field optical head according to claim 8 ,
The magnetic circuit has in part a vertical circuit portion along a direction perpendicular to the facing surface of the slider,
The near-field optical head according to claim 1, wherein the coil is formed in a state in which the coil is spirally wound around the vertical circuit portion so as to spread along the facing surface. A near-field optical head according to claim 8 or 9 ,
The near-field optical head is supported on the tip side in a state that it can move in a direction parallel to the surface of the magnetic recording medium and is rotatable about two axes parallel to the surface of the magnetic recording medium and orthogonal to each other. With the beam,
A light source for making the light beam incident on the light beam introducing means;
An actuator for supporting the base end side of the beam and moving the beam in a direction parallel to the surface of the magnetic recording medium;
A rotation drive unit for rotating the magnetic recording medium in the fixed direction;
An information recording / reproducing apparatus comprising: a controller for supplying the current to the coil and controlling the operation of the light source.

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