JP2011165276A - Method for manufacturing near-field optical head, near-field optical head and information recording and playback device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a near-field optical head while enhancing design flexibility and easily adjusting conditions of a distance between a near-field light generating element and a recording element and light intensity of near-field light and the like, as desired, to provide the near-field optical head and to provide an information recording and playback device. <P>SOLUTION: A core forming step includes a filling step for filling a liquid core material 50 in a recessed part 24c so that an exposed surface of the core material 50 is curved to an aperture surface of the recessed part 24c by surface tension with the recessed part 24c and a curing step for curing the core material 50 to form a core 23 having a curved surface 23c curved to the aperture surface. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a near-field optical head manufacturing method, a near-field optical head, and an information recording / reproducing apparatus for recording and reproducing various kinds of information on a magnetic recording medium by using near-field light collected by a light beam.

  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 eliminate the above-described problems, the coercive force is temporarily reduced by locally heating the magnetic domain using spot light that has collected light, or near-field light that has collected light, In the meantime, an information recording / reproducing apparatus (recording / reproducing head) of a hybrid magnetic recording system that performs writing on a recording medium is provided. In particular, when near-field light is used, it is possible to handle optical information in a region that is less than or equal to the wavelength of light, which is a limit in conventional optical systems. Therefore, it is possible to achieve a higher recording bit density than conventional information recording / reproducing apparatuses.

  A recording / reproducing head (near-field optical head) using near-field light includes an electromagnetic coil element having a main magnetic pole and an auxiliary magnetic pole, and a near-field light generating layer that generates near-field light by receiving laser light from an optical fiber, (For example, refer to Patent Documents 1 and 2). Each of these components is attached in the order of the auxiliary magnetic pole, the main magnetic pole, and the near-field light generating layer on the side surface of the slider fixed to the tip of the beam while being covered with the coating layer. The coating layer includes a layer that serves as an optical waveguide for guiding the laser light emitted from the optical fiber to the near-field light generation layer, and has a multilayer structure in which layers formed of different materials are stacked. ing.

  When the recording / reproducing head configured as described above is used, various information is recorded on the recording medium by generating a near-field light and simultaneously applying a recording magnetic field. That is, when laser light is irradiated from the optical fiber, the laser light propagates through the coating layer and then reaches the near-field light generating layer. Then, in the near-field light generating layer, the internal free electrons are uniformly vibrated by the electric field of the laser beam, so that the plasmon is excited and generates 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 laser light irradiation, a drive current is supplied to the electromagnetic coil element to locally apply a recording magnetic field to the magnetic recording layer of the recording medium close to the main magnetic pole. 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 cooperation between the thermal assist of the near-field light and the magnetic field.

JP 2007-164935 A JP 2007-164936 A

By the way, in order to perform precise and efficient thermal assist using near-field light, conditions such as the distance between the near-field light generation layer and the main magnetic pole (electromagnetic coil element) and the light intensity of the near-field light are required. It is necessary to set the desired conditions.
However, the conventional recording / reproducing head has a problem that it is difficult to adjust the above-described conditions, and the degree of freedom in design is low.

  Therefore, the present invention has been made in view of such circumstances, and its purpose is to improve the degree of design freedom, the distance between the near-field light generating element and the recording element, and the light intensity of the near-field light. It is an object to provide a near-field optical head manufacturing method, a near-field optical head, and an information recording / reproducing apparatus that can easily adjust such conditions as desired conditions.

The present invention provides the following means in order to solve the above-described problems.
A method of manufacturing a near-field optical head according to the present invention includes a light flux propagating element that propagates a light beam toward a magnetic recording medium rotating in a fixed direction, and a near-field light that generates near-field light from the light beam toward the magnetic recording medium. A field light generating element; and a recording element that applies a recording magnetic field to the magnetic recording medium. The magnetic recording medium is heated by the near-field light, and the recording magnetic field is applied to the magnetic recording medium. A method of manufacturing a near-field optical head for recording information by causing magnetization reversal, wherein the light flux propagation element sandwiches the core and a core that guides the magnetic recording medium while reflecting the light flux A first clad forming step for forming the first clad, and a table in which the second clad in the first clad is disposed. Forming a concave portion along the thickness direction, forming a core in the concave portion, and generating the near-field light on the exposed surface of the core formed in the concave portion. A near-field light generating element forming step of forming an element; a second clad forming step of stacking the second clad on the surface side of the first clad so as to seal the core; and the second clad A recording element disposing step of disposing the recording element on the opposite side of the core with a core interposed therebetween, wherein the core forming step includes a liquid core material in the recess and a surface tension with the recess. The filling step of filling the exposed surface of the core material so as to bend with respect to the opening surface of the recess, and the core having a curved surface formed by bending the core material to be curved with respect to the opening surface A curing step to form, And wherein the Rukoto.

According to this configuration, in the core forming step, the liquid core material is filled in the recess, so that the exposed surface of the core material from the recess is curved with respect to the opening surface of the recess due to surface tension with the recess. become. And the core which has a curved surface curved with respect to the opening surface of a recessed part can be formed by hardening a core material in this state. In this case, the radius of curvature of the curved surface of the core is determined by the surface tension of the core material. That is, the distance between the near-field light generating element disposed on the core and the recording element is determined by the curvature radius of the curved surface.
In addition, by forming the core in a curved shape, the area of the orthogonal portion between the normal direction of the curved surface and the in-plane direction of the near-field light generating element (compared to the case where the core is formed flush with the opening surface of the recess) (Area of the interface between the curved surface and the near-field light generating element) can be reduced. As a result, the near-field light can be more localized at the interface between the curved surface and the near-field light generating element, so that the light intensity of the near-field light can be increased and the magnetic recording medium can be heated more efficiently. it can. As a result, the magnetic recording density can be improved. In this case, since the radius of curvature of the curved surface of the core is determined by the surface tension of the core material as described above, the area of the orthogonal portion between the normal direction of the curved surface and the in-plane direction of the near-field light generating element is curved. Determined by the radius of curvature of the surface. That is, the light intensity of near-field light is determined by the curvature radius of the curved surface.
As described above, conditions such as the distance between the near-field light generating element and the recording element and the light intensity of the near-field light can be determined at the manufacturing stage depending on the surface tension of the core material. Conditional near-field optical head can be easily manufactured.

Further, the filling step includes a surface tension adjusting step of adjusting a surface tension of the core material with the concave portion by adjusting a temperature of the core material.
According to this configuration, the surface tension of the core material with the recess can be adjusted by adjusting the temperature of the core material before the core material is cured. That is, the radius of curvature of the curved surface of the core can be adjusted at the manufacturing stage, and the conditions such as the distance between the near-field light generating element and the recording element and the light intensity of the near-field light can be set to desired conditions. The degree of freedom can be further improved.

In the surface tension adjusting step, the exposed surface of the core material is curved in a convex shape with respect to the opening surface.
According to this structure, the core which has the curved surface which curves in a convex shape from a recessed part can be formed by curving the exposed surface of a core material convexly with respect to the opening surface of a recessed part. In this case, the distance between the near-field light generating element and the recording element can be reduced as compared with the case where the core is formed flush with the opening surface of the recess. For this reason, the near-field light can be generated in a state of being brought close to the recording element. As a result, the place where the recording magnetic field is applied and the place heated by the near-field light approach each other, so that the near-field light can accurately and efficiently perform the heat assist, thereby improving the magnetic recording density. Can be planned.
Further, the area of the orthogonal portion between the normal direction of the curved surface and the in-plane direction of the near-field light generating element can be reduced as compared with the case where the core is formed flush with the opening surface of the recess. Thereby, near-field light can be more localized at the interface between the curved surface and the near-field light generating element, so that the light intensity of the near-field light can be increased.

In the surface tension adjusting step, the exposed surface of the core material is curved in a concave shape with respect to the opening surface.
According to this structure, the core which has a curved surface which curves in a concave shape from a recessed part can be formed by curving the exposed surface of a core material concavely with respect to the opening surface of a recessed part. In this case, the second clad enters the recess in the second clad forming step. Therefore, compared to the case where the core is formed flush with the opening surface of the recess, the distance from the opening surface of the recess to the recording element (the thickness of the second cladding) can be reduced. That is, the thickness of the second cladding can be reduced without changing the distance between the near-field light generating element and the recording element. Therefore, it is possible to reduce the thickness of the light propagating element and to reduce the size of the near-field optical head.
Further, the area of the orthogonal portion between the normal direction of the exposed surface and the in-plane direction of the near-field light generating element can be reduced as compared with the case where the core is formed flush with the opening surface of the recess. Thereby, near-field light can be more localized at the interface between the curved surface and the near-field light generating element, so that the light intensity of the near-field light can be increased.

Further, the near-field optical head according to the present invention is a recording / reproducing head manufactured using the method for manufacturing a near-field optical head according to the present invention, wherein the curved surface is formed in a concave shape with respect to the opening surface. It is characterized by being.
According to this configuration, since the second cladding enters the recess, the distance from the opening surface of the recess to the recording element (the second cladding) as compared with the case where the core is formed flush with the opening surface of the recess. Thickness) can be reduced. That is, the thickness of the second cladding can be reduced without changing the distance between the near-field light generating element and the recording element. Therefore, it is possible to reduce the thickness of the light propagating element and to reduce the size of the near-field optical head.

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 that moves the beam in a direction parallel to the surface of the magnetic recording medium, a rotation drive unit that rotates the magnetic recording medium in the fixed direction, and a control unit that controls the operation of the light source. It is characterized by having.
According to this configuration, since the near-field optical head of the present invention is provided, writing reliability is high, high-density recording can be supported, and high quality can be achieved.

According to the method of manufacturing a near-field light head and the near-field light head according to the present invention, the conditions such as the distance between the near-field light generating element and the recording element, the light intensity of the near-field light, and the like can be easily adjusted to desired conditions. It is possible to perform precise and efficient heat assist.
The information recording / reproducing apparatus according to the present invention has high writing reliability, can cope with high density recording, and can achieve high quality.

It is a block diagram of the information recording / reproducing apparatus in embodiment of this invention. It is an expanded sectional view of the recording / reproducing head in 1st Embodiment. FIG. 3 is an enlarged cross-sectional view of a side surface on the outflow end side of the recording / reproducing head in the first embodiment. It is A arrow directional view of FIG. FIG. 4 is a view taken in the direction of arrow B in FIG. 3. It is the figure which expanded the periphery of a laser light source. FIG. 6 is a process diagram illustrating a method for manufacturing a recording / reproducing head, and is a plan view corresponding to FIG. 5. FIG. 6 is a process diagram illustrating a method for manufacturing a recording / reproducing head, and is a plan view corresponding to FIG. 5. It is explanatory drawing at the time of recording / reproducing information with an information recording / reproducing apparatus, Comprising: It is an expanded sectional view corresponded in FIG. FIG. 6D is a process diagram showing a recording / reproducing head manufacturing method according to a second embodiment, and is a plan view corresponding to FIG. 5. FIG. 6 is an enlarged plan view of a recording / reproducing head in a second embodiment. FIG. 10 is a process diagram illustrating a method of manufacturing a recording / reproducing head in a modification of the second embodiment, and is a plan view corresponding to FIG. 5. It is an enlarged plan view of a recording / reproducing head in a modification of the second embodiment. It is an expanded sectional view of the recording / reproducing head in 3rd Embodiment. It is E arrow line view of FIG. It is explanatory drawing at the time of recording / reproducing information with an information recording / reproducing apparatus, Comprising: It is an expanded sectional view corresponded in FIG. It is explanatory drawing at the time of recording / reproducing information with an information recording / reproducing apparatus, Comprising: It is an expanded sectional view corresponded in FIG. FIG. 16 is an enlarged plan view corresponding to FIG. 15 showing a modification of the third embodiment.

(First embodiment)
Next, a first embodiment of the present invention will be described with reference to the drawings.
Note that the information recording / reproducing apparatus 1 of the present embodiment uses the hybrid magnetic recording method in which the near-field light R and the recording magnetic field cooperate with the disk D (magnetic recording medium) D having the perpendicular recording layer d2. This is an apparatus for recording and reproducing (see FIG. 2).

(Information recording / reproducing device)
FIG. 1 is a block diagram of an information recording / reproducing apparatus.
As shown in FIG. 1, the information recording / reproducing apparatus 1 of the present embodiment includes a recording / reproducing head 2, a beam 3 that supports the recording / reproducing head 2, and a laser beam (light beam) L (see FIG. 2). ), An actuator 5 that moves the beam 3, a spindle motor (rotation drive unit) 6 that rotates the disk D in a fixed direction, and a control unit that comprehensively controls each of the above-described components. 8 and a housing 9 that accommodates each component 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. A spindle motor 6 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 6. In the present embodiment, the case where three disks D are fixed to the spindle motor 6 is described as an example. However, the number of disks D is not limited to three.

  An actuator 5 is attached to the corner of the recess 9a. A carriage 11 is attached to the actuator 5 via a bearing 10. The carriage 11 is formed by cutting, for example, a metal material, and a portion from the base end portion 11 a fixed to the actuator 5 via the bearing 10 toward the front end is disposed on the upper surface of the three disks D. Thus, it has a three-layer structure. That is, it is formed so as to be E-shaped when the carriage 11 is viewed from the side. The proximal end side of the beam 3 is fixed to each distal end of the carriage 11 divided into three layers. Therefore, the actuator 5 supports the base end side of the beam 3 via the carriage 11 and can scan and move the beam 3 in the XY directions parallel to the disk surface (the surface of the magnetic recording medium) D1. It is like that.

  The beam 3 is movable in the XY direction together with the carriage 11 by the actuator 5 as described above, and is rotatable about two axes (X axis, Y axis) parallel to the disk surface D1 and orthogonal to each other. In this state, the recording / reproducing head 2 is supported on the tip side. The beam 3 and the carriage 11 are retracted from the disk D by driving the actuator 5 when the rotation of the disk D is stopped.

(Recording / reproducing head)
FIG. 2 is an enlarged sectional view of the recording / reproducing head, and FIG. 3 is an enlarged sectional view of the side surface on the outflow end side of the recording / reproducing head.
As shown in FIGS. 2 and 3, the recording / reproducing head 2 is a head that records and reproduces various information on a rotating disk D using near-field light R generated from laser light L. The recording / reproducing head 2 includes a slider 20 that is opposed to the disk D in a state of floating a predetermined distance H from the disk surface D1, a recording element 21 that records information on the disk D, and information recorded on the disk D. A reproducing element 22 for reproducing and a near-field light generating element 26 for generating near-field light R (see FIG. 9) from the introduced laser light L are provided. Further, the recording / reproducing head 2 of this embodiment includes a light flux propagation element 25 including a core 23 and a clad 24.

  The slider 20 is formed in a rectangular parallelepiped shape from a light transmissive material such as quartz glass, a ceramic such as AlTiC (altic), or the like. The slider 20 has a facing surface 20a facing the disk D, and is supported so as to hang from the tip of the beam 3 via a gimbal portion 30 (see FIG. 2). The gimbal portion 30 is a component whose movement is restricted so as to be displaced only around the X axis and around the Y axis. As a result, the slider 20 is rotatable about two axes (X axis and Y axis) that are parallel to the disk surface D1 and orthogonal to each other as described above.

  Further, on the facing surface 20a, there is formed a ridge portion 20b that generates a pressure for rising from the viscosity of the air flow generated by the rotating disk D. The ridges 20b are formed so as to extend along the longitudinal direction (X direction), and two are formed on the left and right sides (Y direction) at intervals so as to be arranged in a rail shape. However, the ridge portion 20b is not limited to this case, and adjusts a positive pressure for separating the slider 20 from the disk surface D1 and a negative pressure for attracting the slider 20 to the disk surface D1, Any uneven shape may be used as long as the slider 20 is designed to float in an optimal state. The surface of the ridge portion 20b is called an ABS (Air Bearing Surface) 20c.

The slider 20 receives a force that rises from the disk surface D1 by the two ridges 20b. On the other hand, the beam 3 is bent in the Z direction perpendicular to the disk surface D1, and absorbs the flying force of the slider 20. That is, the slider 20 receives a force pressed against the disk surface D1 side by the beam 3 when it floats. Therefore, the slider 20 floats in a state of being separated from the disk surface D1 by a predetermined distance H as described above due to the balance between the forces of the two. Moreover, since the slider 20 is rotated about the X axis and the Y axis by the gimbal portion 30, it always floats in a state where the posture is stable.
The air flow generated by the rotation of the disk D flows from the inflow end side (the X direction base end side of the beam 3) of the slider 20 and then flows along the ABS 20c, and flows out of the slider 20 (the beam 3). From the X direction tip side).

  As shown in FIG. 3, the recording element 21 is an element that records information by applying a recording magnetic field to the disk D, and includes an auxiliary magnetic pole 31 fixed to a side surface (tip surface) on the outflow end side of the slider 20. The main magnetic pole 33 is connected to the auxiliary magnetic pole 31 via the magnetic circuit 32 and generates a recording magnetic field perpendicular to the disk D between the auxiliary magnetic pole 31 and the magnetic circuit 32 around the magnetic circuit 32. And a coil 34 wound spirally. That is, the auxiliary magnetic pole 31, the magnetic circuit 32, the coil 34, and the main magnetic pole 33 are arranged in order from the outflow end side of the slider 20.

  Both the magnetic poles 31 and 33 and the magnetic circuit 32 are made of a high saturation magnetic flux density (Bs) material (for example, a CoNiFe alloy, a CoFe alloy, etc.) having a high magnetic flux density. The coil 34 is arranged so that there is a gap between adjacent coil wires, between the magnetic circuit 32 and between the magnetic poles 31 and 33 so as not to be short-circuited. Molded. The coil 34 is supplied with a current modulated according to information from the control unit 8. That is, the magnetic circuit 32 and the coil 34 constitute an electromagnet as a whole. The main magnetic pole 33 and the auxiliary magnetic pole 31 are designed such that the end face (Z-direction end face) facing the disk D is flush with the ABS 20c of the slider 20.

4 is a view as seen from an arrow A in FIG. 3, and FIG. 5 is a view as seen from an arrow B in FIG.
As shown in FIGS. 3 to 5, the light beam propagation element 25 has an incident side (one end side in the Z direction) of the laser light L facing upward of the slider 20 and an emission side (the other end side in the Z direction) on the disk D side. In the state of facing, is fixed adjacent to the X direction side of the main magnetic pole 33 of the recording element 21. The light flux propagation element 25 is composed of a core 23 for propagating the laser light L introduced from one end side to the other end side facing the disk D, and a clad 24 in close contact with the core 23. It is formed in a shape.

  The core 23 is gradually drawn from one end side to the other end side so that the laser beam L can be propagated while being gradually condensed inside. Specifically, the core 23 has a reflecting surface 23a, a light beam condensing unit 23b, and a near-field light generating unit 23g from one end side, and is formed in a fan shape when viewed from the optical axis direction of the laser light L. . In addition, as a material which forms the core 23 of this embodiment, it is preferable to use an ultraviolet curable resin material.

The reflection surface 23a reflects laser light L introduced from an optical waveguide 42 described later in a direction different from the introduction direction. In the present embodiment, the direction of the laser beam L is reflected so as to change approximately 90 degrees. The laser light L introduced from the optical waveguide 42 by the reflecting surface 23a propagates toward the other end side while repeating total reflection in the core 23.
The light beam condensing part 23b is a portion formed by drawing so that the cross-sectional area (cross-sectional area in the XY direction) perpendicular to the longitudinal direction (Z direction) from one end side to the other end side gradually decreases. The laser light L is condensed and propagated toward the other end side. That is, the spot size of the laser beam L introduced into the light beam condensing unit 23b can be gradually reduced to a smaller size.
The near-field light generating part 23g is a part that is further drawn from the end of the light beam condensing part 23b toward the other end. Specifically, in the vicinity of the other end side of the core 23, an inclined surface 23h formed so as to face the reproducing element 21 while being inclined with respect to the optical axis (Z direction) of the laser light L propagating inside. Is drawn. Due to the inclined surface 23h, the core 23 is pointed on the other end side.

  In the present embodiment, the light beam condensing unit 23b and the near-field light generating unit 23g are formed to have three side surfaces, and one of the side surfaces has the clad 24 (base end side clad 24a) therebetween. It is arranged so as to face the main magnetic pole 33 with being sandwiched. In this case, a surface facing the main magnetic pole 33 is formed on a curved surface 23c that curves convexly toward the main magnetic pole 33, and a flat surface 23d that tapers toward the reproducing element 22 from both ends in the circumferential direction of the curved surface 23c. By being formed, the core 23 is formed in a fan shape when viewed from the optical axis direction of the laser beam L. Therefore, as shown in FIG. 5, the end surface 23e exposed to the outside on the other end side of the near-field light generating unit 23g is formed in a fan shape. The end face 23e is designed to be flush with the ABS 20c of the slider 20. The radius of curvature of the curved surface 23c is formed as R0.

  3 and 4, the clad 24 is formed of a material having a refractive index lower than that of the core 23, and the end surface 23e on one end side and the other end side of the core 23 is exposed to the outside. In close contact with the side surface (curved surface 23c) of the core 23, the core 23 is sealed inside. Specifically, the clad 24 includes a base-side clad (second clad) 24a formed between the core 23 and the recording element 21 (main magnetic pole 33) so as to cover the curved surface 23c side of the core 23, and the core. A front end side clad (first clad) 24b formed so as to cover the flat surface 23d side. As described above, the base end side clad 24 a and the front end side clad 24 b are in close contact with the side surface of the core 23, so that no gap is generated between the core 23 and the clad 24.

As shown in FIG. 5, the near-field light generating element 26 is a metal film made of, for example, gold (Au), platinum (Pt), aluminum (Al), or the like, and is formed on the curved surface 23c of the near-field light generating unit 23g. Is formed. That is, the near-field light generating element 26 is disposed to face the main magnetic pole 33 with the proximal end side cladding 24a interposed therebetween. The near-field light emitting element 26 generates near-field light R from the laser light L propagating in the core 23 and localizes the near-field light R between the other end side of the light flux propagation element 25 and the disk D. Is. In the present embodiment, the distance between the near-field light generating element 26 and the main magnetic pole 33 is set to d0.
Further, the polarization direction of the laser light L of the present embodiment is adjusted so as to be linearly polarized light parallel to the disk D (the direction of arrow P in FIG. 5). For this reason, the polarization direction of the laser light L coincides with the thickness direction (X direction) of the near-field light generating element 26 when the laser light L reaches the near-field light generating unit 23g.

  Incidentally, as shown in FIG. 3, an optical waveguide 42 is fixed to the upper surface (one end side in the Z direction) of the slider 20. The optical waveguide 42 is a biaxial waveguide composed of a core 42a and a clad 42b, and the laser light L propagates through the core 42a. The tip of the optical waveguide 42 is connected to one end side of the core 23 of the light flux propagation element 25, and emits the laser light L toward the reflecting surface 23a. The core 42a and the clad 42b are made of the same material as the core 23 and the clad 24 described above.

On the other hand, the base end side of the optical waveguide 42 is drawn out along the beam 3 and the carriage 11 and then connected to the laser light source 43 as shown in FIG. As shown in FIGS. 1 and 6, the laser light source 43 is mounted on the control board 44 attached to the side surface of the base end portion 11 a of the carriage 11 together with various electronic components such as an IC chip (not shown). In particular, the laser light source 43 emits the laser light L in a linearly polarized state. That is, the laser light source 43 and the optical waveguide 42 function as a light beam incident mechanism 4 that causes the laser light L to enter the recording / reproducing head 2 in a linearly polarized state. FIG. 6 is an enlarged view of the periphery of the laser light source.
The control board 44 on which the laser light source 43 is mounted is connected to the control unit 8 by a flexible flat cable (flexible board) 45. Thus, the control unit 8 performs an overall control by sending an electrical signal to each component. In particular, the timing at which the laser light source 43 emits the laser light L is controlled by the control unit 8.

  The reproducing element 22 is a magnetoresistive film whose electric resistance is converted in accordance with the magnitude of the magnetic field leaking from the perpendicular recording layer d2 of the disk D. What is the recording element 21 with the light flux propagation element 25 interposed therebetween? It is formed on the surface of the opposite clad 24 (front end clad 24b). A bias current is supplied to the reproducing element 22 from the control unit 8 via a lead film (not shown). Thus, the control unit 8 can detect a change in the magnetic field leaking from the disk D as a change in voltage, and can reproduce a signal from the change in voltage.

As shown in FIG. 2, the disk D of this embodiment includes at least a perpendicular recording layer d2 having an easy magnetization axis in a direction perpendicular to the disk surface D1, and a soft magnetic layer d3 made of a high magnetic permeability material. A vertical two-layer disc D composed of two layers is used. As such a disk D, for example, a disk in which 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 is used. .
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.

(Method for manufacturing recording / reproducing head)
Next, a method for manufacturing the recording / reproducing head described above will be described. In the following description, a method for manufacturing the light flux propagation element 25 in the recording / reproducing head 2 described above will be mainly described. 7 and 8 show a plane corresponding to FIG. 5, and are process diagrams for explaining a method of manufacturing the recording / reproducing head.
First, as shown in FIG. 7A, the leading end side cladding 24b is formed on the reproducing element 22 (first cladding forming step). Then, in the formation region of the core 24 in the distal clad 24b, a concave portion 24c cut along the thickness direction of the surface where the proximal clad 24a is disposed later is formed (recess formation step). Specifically, the recess 24c can be formed by performing wet etching, ion etching, RIE (Reactive Ion Etching), nanoimprinting, pressing, or the like on the core 24 forming region of the front-side clad 24b. By using the method as described above, a V-shaped concave portion 24c is formed on the front end side cladding 24b. In addition, as shown in FIG. 3, this recessed part 24c is formed so that a depth may become shallow as it goes to the other end side from the one end side of the front end side clad 24b. As a result, the cross-sectional area in the XY direction of the core 23 to be formed in the recess 24c later is drawn as it goes from one end side to the other end side.

Next, the core 23 is formed in the recessed part 24c of the front end side clad 24b (core formation process).
First, as shown in FIG. 7C, the liquid core material 50 that will later become the core 23 is filled into the recess 24 c formed in the recess forming process by using, for example, an injection method or a spin coat method (filling). Process). In addition, when filling the core material 50 using the injection method mentioned above, the core material 50 is directly filled into the recessed part 24c from a nozzle. Thereby, the core material 50 can be filled with high precision only in the recess 24c. Further, when the core material 50 is filled by using the spin coating method, the core material 50 is applied to a portion other than the concave portion 24c and the concave portion 24c (the surface of the front end side clad 24b), and then the reproducing element 22 and the front end side clad 24b. Is rotated to cause the core material 50 formed in a portion other than the recess 24c to scatter, leaving the core material 50 only in the recess 24c. Thereby, after reducing manufacturing cost, the core material 50 can be filled only in the recessed part 24c with high precision. In this state, the temperature of the core material 50 is T0.

  Here, the surface of the core material 50 filled in the recess 24c (exposed surface from the recess 24c) is an opening surface of the recess 24c (the base in the front cladding 24b) due to surface tension with the recess 24c (tip cladding 24b). It has a convex curved surface (exposed surface) 50a that rises from the surface facing the end clad 24a. That is, when the adhesion force between the inner surface of the recess 24c and the core material 50 is W and the surface tension when the temperature of the core material 50 is T0 is S0, the intermolecular force A0 (A0 = S0 cos θ0) of the core material 50 is the adhesion force W. (A0> W). In this state, the radius of curvature of the curved surface 50a of the core material 50 is R0, and the height of the protruding portion of the curved surface 50a from the surface of the tip side cladding 24b is h0.

  Next, as shown in FIG. 7D, the core material 50 filled in the recess 24c is cured by irradiating the core material 50 with ultraviolet rays (curing step). Thereby, the core 23 having the flat surface 23d formed following the inner surface of the recess 24c and the curved surface 23c (curvature radius R0, height h0) curved in a convex shape from the opening surface of the recess 24c can be formed.

Then, as shown in FIG. 8A, a metal film made of Al or the like is formed on the curved surface 23c of the core 23 using an evaporation method or the like, and is patterned, so that the curved surface of the near-field light generating unit 23g. The near-field light generating element 26 is formed on 23c.
Next, as shown in FIG. 8B, the base-side clad 24a is formed so as to cover the curved surface 23c of the core 23 (second clad forming step). Thereby, the light flux propagation element 25 sealed with the core 23 in close contact with each other can be formed inside the distal end side cladding 24b and the proximal end side cladding 24a.

  Subsequently, as shown in FIG. 8C, the main magnetic pole 33 is formed so as to face the near-field light generating element 26 with the proximal-side clad 24a interposed therebetween. Thereafter, although not shown, the magnetic circuit 32, the coil 34, and the auxiliary magnetic pole 31 are formed, and these are molded by the insulator 35. Thereby, the light flux propagation element 25, the near-field light element 26, and the recording element 21 are formed on the reproducing element 22. In this state, the recording / reproducing head 2 can be formed by fixing the recording element 21 to the side surface of the slider 20. In the above description, the case where the recording element 21 is formed on the reproducing element 22 and then fixed to the side surface of the slider 20 has been described. However, while the element up to the light beam propagation element 25 is formed on the reproducing element 22, the slider 20 Alternatively, the recording elements 21 may be formed on the side surfaces and combined.

(Information recording and playback method)
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, as shown in FIG. 1, the spindle motor 6 is driven to rotate the disk D in a certain direction. Next, the actuator 5 is operated to scan the beam 3 in the XY directions via the carriage 10. Thereby, the recording / reproducing head 2 can be positioned at a desired position on the disk D. At this time, the recording / reproducing head 2 receives a force that rises by the two ridges 20b formed on the opposing surface 20a of the slider 20, and is pressed against the disk D by a predetermined force by the beam 3 or the like. The recording / reproducing head 2 floats to a position separated from the disk D by a predetermined distance H as shown in FIG.

  Further, even if the recording / reproducing head 2 receives wind pressure generated due to the undulation of the disk D, the displacement in the Z direction is absorbed by the beam 3 and can be displaced around the XY axis by the gimbal portion 30. Since it has become possible, it can absorb the wind pressure caused by the swell. Therefore, the recording / reproducing head 2 can be floated in a stable state.

FIG. 9 is an explanatory diagram when information is recorded / reproduced by the information recording / reproducing apparatus, and is an enlarged sectional view corresponding to FIG.
Here, as shown in FIG. 9, when recording information, the control unit 8 operates the laser light source 43 to emit linearly polarized laser light L, and a current modulated in accordance with the information is supplied to the coil 34. Then, the recording element 21 is operated.
First, laser light is incident on the optical waveguide 42 from the laser light source 43 to guide the laser light L to the slider 20 side. The laser light L emitted from the laser light source 43 travels in the core 42 a of the optical waveguide 42 toward the tip (outflow end) side and propagates into the core 23 of the light flux propagation element 25. The laser beam L that has propagated into the core 23 is reflected by approximately 90 degrees on the reflecting surface 23a, and then propagates in the light beam condensing part 23b. The laser light L propagating through the light beam condensing unit 23b propagates while repeating total reflection between the core 23 and the clad 24 toward the other end side located on the disk D side. In particular, since the clad 24 is in close contact with the side surface of the core 23, light does not leak outside the core 23. Therefore, the introduced laser light L can be propagated to the other end side without being wasted and incident on the near-field light generating element 26 without being wasted.
At this time, the core 23 is drawn so that the cross-sectional area perpendicular to the longitudinal direction (Z direction) from one end side to the other end side gradually decreases. Therefore, the laser beam L is gradually narrowed down as it propagates in the light flux collecting rear part 23b, and the spot size is reduced.

  Subsequently, the laser beam L having a reduced spot size is incident on the near-field light generator 23g. Then, the laser light L enters the near-field light generating element 26 of the exposed portion 23f. As a result, surface plasmons are excited in the near-field light generating element 26. The excited surface plasmon propagates toward the other end of the core 23 along the interface between the near-field light generating element 26 and the core 23 (near-field light generating unit 23g) while being enhanced by the resonance effect. And when it reaches the other end side, it becomes a near-field light R with a strong light intensity and leaks outside. That is, the near-field light R can be localized between the other end side of the light flux propagation element 25 and the disk D. Then, the disk D is locally heated by the near-field light R, and the coercive force is temporarily reduced.

  Here, the surface of the core 23 (near-field light generating part 23g) facing the main magnetic pole 33 is formed on the curved surface 23c. Therefore, as compared with the case where the surface facing the main magnetic pole 33 is formed as a flat surface, the orthogonal portion between the polarization direction of the laser light L (arrow P in FIG. 5) and the in-plane direction of the near-field light generating element 26. (The area (contact area) of the interface between the curved surface 23c and the near-field light generating element 26) can be reduced. As a result, the near-field light R can be more localized at the interface between the curved surface 23c and the near-field light generating element 26, so that the light intensity of the near-field light R can be increased and the disk D can be made more efficient. Can be heated.

  On the other hand, when a current is supplied to the coil 34 by the control unit 8, a current magnetic field generates a magnetic field in the magnetic circuit 32 according to the principle of an electromagnet. A perpendicular recording magnetic field can be generated. Then, the magnetic flux generated from the main magnetic pole 33 side passes straight through the perpendicular recording layer d2 of the disk D and reaches the soft magnetic layer d3. 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 31 via the soft magnetic layer d3. At this time, when returning to the auxiliary magnetic pole 31, the direction of magnetization is not affected. This is because the area of the auxiliary magnetic pole 31 facing the disk surface D1 is larger than that of the main magnetic pole 33, 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 33 side.

  As a result, information can be recorded by the hybrid magnetic recording method in which the thermal assist by the near-field light R and the recording magnetic field generated by the magnetic poles 31 and 33 cooperate. In addition, 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.

Further, when reproducing information recorded on the disk D, the reproducing element 22 receives a magnetic field leaking from the perpendicular recording layer d2 of the disk D when the coercive force of the disk D is temporarily reduced. Thus, the electrical resistance changes according to the size. Therefore, the voltage of the reproducing element 22 changes. Thereby, the control unit 8 can detect a change in the magnetic field leaking from the disk D as a change in voltage. The control unit 8 can reproduce information recorded on the disk D by reproducing a signal from the change in voltage.
When recording / reproduction is not performed, the operation of the laser light source 43 is stopped.

Therefore, according to the present embodiment, in the core forming step, the liquid core material 50 is filled into the recess 24c, so that the exposed surface of the core material 50 from the recess 24c is recessed by the surface tension S0 with the recess 24c. It will curve with respect to the opening surface of 24c.
And the core 23 which has the curved surface 23c curved with respect to the opening surface of the recessed part 24c can be formed by hardening the core material 50 in this state. In this case, the curvature radius R0 of the curved surface 23c of the core 23 is determined by the surface tension S0 of the core material 50. That is, the distance between the near-field light generating element 26 disposed on the core 23 and the recording element 21 is determined by the radius of curvature of the curved surface 23c.

Accordingly, the distance d0 between the near-field light generating element 26 and the main magnetic pole 33 can be reduced as compared with the case where the surface of the core 23 facing the main magnetic pole 33 is formed as a flat surface. R can be generated in a state of being close to the main magnetic pole 33. As a result, the place where the recording magnetic field is applied and the place heated by the near-field light R approach each other, so that the near-field light R can perform heat assist accurately and efficiently, and the magnetic recording density Improvements can be made.
Further, by curving the core 23 as described above, the light intensity of the near-field light R can be increased compared to the case where the surface of the core 23 facing the main magnetic pole 33 is formed as a flat surface. The disk D can be heated more efficiently. As a result, the magnetic recording density can be improved. In this case, as described above, the curvature radius R0 of the curved surface 23c of the core 23 is determined by the surface tension S0 of the core material 50, so that the polarization direction of the laser light L (arrow P in FIG. 5) and the near-field light generating element. The area of the portion perpendicular to the in-plane direction of 26 is determined by the radius of curvature R0 of the curved surface 23c. That is, the light intensity of the near-field light R is determined by the radius of curvature of the curved surface 23c.

As described above, conditions such as the distance d0 between the near-field light generating element 26 and the main magnetic pole 33 and the light intensity of the near-field light R can be determined by the surface tension S0 of the core material 50 at the manufacturing stage. The recording / reproducing head 2 under desired conditions can be easily manufactured. Therefore, precise and efficient heat assist can be performed.
Since the information recording / reproducing apparatus 1 of the present invention includes the recording / reproducing head 2 described above, information can be recorded / reproduced with high accuracy and high quality.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. FIG. 10 is a process diagram for explaining a core formation process in the second embodiment. In the present embodiment, a method for adjusting the radius of curvature of the curved surface 23c in the core forming step described above will be described. Therefore, in the following description, the core forming process will be mainly described, and the description of the same configuration as that of the first embodiment will be omitted. A chain line C in the figure indicates the curved surface 50a of the core material 50 at the temperature T0.
As shown in FIG. 10, after completion of the filling step, the core material 50 is cooled and adjusted to a temperature T1 lower than the temperature T0 of the core material 50 of the first embodiment (T0> T1). Thereby, the surface tension S1 of the core material 50 becomes larger than the surface tension S0 when the temperature is T0 (S1> S0), and the core material 50 rises greatly from the opening surface of the recess 24c. That is, the intermolecular force A1 at the temperature T1 in the core material 50 is larger than the intermolecular force A0 at the temperature T0 (A1> A0), and therefore the intermolecular force A1 of the core material 50 (A1 = S1 cos θ1). Becomes larger than the adhesive force W (A1> W). As a result, the curvature radius R1 of the curved surface 50a is smaller than the curvature radius R0 of the first embodiment (R0> R1), and the height h1 of the curved surface 50a is also increased (h0 <h1).

  And after hardening the core material 50 in the state which kept the temperature of the core material 50 at T1, by passing through the process similar to 1st Embodiment mentioned above, as shown in FIG. 11, curvature radius R1 and height The recording / reproducing head 100 having the curved surface 23c of h1 can be formed.

According to this configuration, the surface tension between the core material 50 and the recess 24c can be adjusted by adjusting the temperature of the core material 50 before the core material 50 is cured. That is, since the curvature radius and height of the curved surface 23c of the core 23 can be adjusted at the manufacturing stage, conditions such as the distance between the near-field light generating element 26 and the main magnetic pole 33, the light intensity of the near-field light R, and the like are desired. Can be set to conditions. As a result, the degree of freedom in design can be improved.
Here, as described above, by increasing the height h1 of the curved surface 23c as compared with the first embodiment, the near-field light generating element 26 can be brought closer to the main magnetic pole 33 as compared with the first embodiment. (Distance d1 in FIG. 11) Therefore, heat assist can be performed more precisely and efficiently.
Further, since the radius of curvature of the curved surface 23c can be reduced, the area of the orthogonal portion between the polarization direction of the laser light L and the in-plane direction of the near-field light generating element 26 can be further reduced as compared with the first embodiment. . As a result, the near-field light R can be more localized at the interface between the curved surface 23c and the near-field light generating element 26, so that the light intensity of the near-field light R can be increased and the disk D can be made more efficient. Can be heated.

(Modification)
FIG. 12 is a process diagram for explaining a core formation process in a modification of the second embodiment. In the second embodiment described above, the method of cooling the core material 50 in order to increase the intermolecular force A1 of the core material 50 in the surface tension adjustment step has been described. However, the intermolecular force is heated by heating the core material 50. It is also possible to reduce A2.
Specifically, as shown in FIG. 12, after completion of the filling process, the regenerative element 22 is transferred to a heating device such as a hot plate or an oven, and the temperature of the core material 50 is set to the temperature of the core material 50 of the first embodiment. The temperature is adjusted to a temperature T2 higher than T0 (T2> T0). Thereby, the surface tension S2 of the core material 50 becomes smaller than the surface tension S0 when the temperature is T0 (S0> S2), and the core material 50 is bent in a concave shape so as to be recessed from the opening surface of the recess 24c. That is, the intermolecular force A2 at the temperature T2 in the core material 50 is smaller than the intermolecular force A0 at the temperature T0 (A0> A2), so the intermolecular force A2 of the core material 50 (A2 = S2 cos θ2). Becomes smaller than the adhesive force W (A2 <W). In this case, the radius of curvature of the curved surface 50a is R2, and the height of the curved surface 50a (the depth from the surface of the distal clad 24b) is h2.

  And after hardening the core material 50 in the state which maintained the temperature of the core material 50 at T2, as shown in FIG. 13 by going through the process similar to 1st Embodiment mentioned above, curvature radius R2 and height The recording / reproducing head 150 having the curved surface 23c of h2 can be formed.

According to this configuration, the same effects as those of the second embodiment described above can be obtained, and the curved surface 23c is formed in a concave shape with respect to the surface of the distal end side cladding 24b. The base end side cladding 24a enters the recess 24c (inside the curved surface 23c of the core 23). Therefore, compared to the case where the core 23 is formed on a flat surface, the distance from the opening surface of the recess 24c to the main magnetic pole 33 (the thickness of the base-side clad 24a) can be reduced. That is, the thickness of the base-end-side cladding 23a can be reduced without changing the distance d0 between the near-field light generating element 26 and the main magnetic pole 33. Therefore, the length of the recording / reproducing head 150 in the X direction can be shortened and the size can be reduced.
Further, since the surface facing the near-field light generating element 26 is the curved surface 23c, the near-field light R is more localized at the interface between the curved surface 23c and the near-field light generating element 26 as in the above-described embodiment. And the light intensity of the near-field light R can be increased.

(Third embodiment)
(Recording / reproducing head)
Next, a third embodiment of the present invention will be described. FIG. 14 is an enlarged cross-sectional view of the side surface on the outflow end side of the recording / reproducing head in the third embodiment, and FIG. 15 is a view taken in the direction of arrow E in FIG. The third embodiment is different from the first embodiment described above in that a space is provided between the near-field light generating element 26 and the main magnetic pole 33.
As shown in FIGS. 14 and 15, the recording / reproducing head 200 of this embodiment is turned from the end surface on the other end side (the ABS 20 c side of the slider 20) of the proximal end side cladding 24 a in the light beam propagation element 25 toward one end side. A cutout portion 24d is formed therethrough. This notch 24d is located at the center of the slider 20 in the width direction (Y direction in FIG. 15), that is, in the region where the curved surface 23c of the core 23 and the main magnetic pole 33 face each other. It is formed with a depth equivalent to the length in the Z direction of the near-field light generator 23g from the end face. Thereby, on the other end side of the light flux propagation element 25, a space 51 is formed between the near-field light generating element 26 and the main magnetic pole 33, and the curved surface 23c (near-field light) of the near-field light generating part 23g. An exposed portion 23f is formed in which the generating element 26) is exposed toward the notch 24d. In this case, the near-field light generating element 26 and the main magnetic pole 33 are disposed to face each other across the interval d0 in the X direction.

  When the recording / reproducing head of this embodiment is manufactured, the base-side clad 24a may be patterned so that the near-field light generating element 26 is exposed in the above-described second clad formation step.

(Information recording and playback method)
Next, a recording / reproducing method using the recording / reproducing head of this embodiment will be described. 16 and 17 are explanatory diagrams when information is recorded / reproduced by the information recording / reproducing apparatus. FIG. 16 is an enlarged sectional view corresponding to FIG. 14, and FIG. 17 is an enlarged plan view corresponding to FIG. In the following description, the operation of the space 51 during recording / reproduction will be mainly described.
As shown in FIGS. 16 and 17, when the laser light L is introduced into the light flux propagation element 25 (core 23), the near-field light generating element 26 and the light flux propagation element 25 are heated by the heat of the laser light L. Then, along with this temperature change, the exposed portion 23 f is thermally expanded so as to protrude toward the main magnetic pole 33, thereby bringing the near-field light generating element 26 closer to the main magnetic pole 33. As a result, the distance d3 between the near-field light generating element 26 and the main magnetic pole 33 in the operating state where the laser light L is introduced is narrower than the distance d0 in the initial state where the laser light L is not introduced. . Therefore, the near-field light R can be generated in a state where the near-field light R is closer to the main magnetic pole 33.

  Further, since the exposed portion 23f is formed on the curved surface 23c, the curvature radius R3 of the exposed portion 23f is smaller than the curvature radius R0 of the exposed portion 23f in the initial state due to thermal expansion of the exposed portion 23f ( R0> R3). Therefore, the area of the orthogonal portion between the polarization direction of the laser light L (arrow P in FIG. 17) and the in-plane direction of the near-field light generating element 26 (area of the interface between the exposed portion 23f and the near-field light generating element 26 (contact) Area)) can be reduced. As a result, the near-field light R can be more localized at the interface between the exposed portion 23f and the near-field light generating element 26, so that the light intensity of the near-field light R can be increased and the disk D can be made more efficient. Can be heated.

By the way, if the near-field light generating element 26 continues to be disposed in the vicinity of the main magnetic pole 33, the magnetic characteristics of the main magnetic pole 33 change due to the heat generated when the near-field light R is generated, which may adversely affect the magnetic recording performance.
On the other hand, in this embodiment, since the space 51 is formed between the exposed portion 23f (near-field light generating element 26) and the main magnetic pole 33, the heat generated in the near-field light generating element 26 is The heat is efficiently radiated to the atmosphere. Therefore, it is possible to suppress the heat generated by the near-field light generating element 26 from being transmitted to the main magnetic pole 33 side. Further, when the laser light source 43 is stopped, the temperature of the near-field light generating element 26 is quickly lowered. Then, the light flux propagation element 25 contracts along with this temperature change, so that the distance between the near-field light generating element 26 and the main magnetic pole 33 is expanded and restored to the initial distance d0. Thereby, it is possible to reliably suppress the heat generated by the near-field light generating element 26 from being transmitted to the main magnetic pole 33 side.

  As described above, according to the present embodiment, the same effects as those of the first embodiment described above can be obtained. First, at the time of recording / reproducing (when the laser beam L is introduced), the exposed portion 23f is caused by the heat of the near-field light R. By thermal expansion, the near-field light generating element 26 can be brought close to the main magnetic pole 33. As a result, the near-field light R can be generated in a state of being closer to the main magnetic pole 33 side. In this case, the place where the recording magnetic field is applied on the disk D and the place heated by the near-field light R are close to each other, so that heat assistance can be performed accurately and efficiently, and the magnetic recording density is improved. be able to.

On the other hand, when recording / reproduction is stopped (when the laser beam L is not introduced), the heat generated by the near-field light generating element 26 is efficiently radiated into the space 51 (atmosphere), thereby generating near-field light. The temperature of the element 26 quickly decreases, and the exposed portion 23f contracts. Thereby, since the near-field light generating element 26 is separated from the main magnetic pole 33 to the distance d0, it is possible to suppress the heat of the near-field light generating element 26 from being transmitted to the main magnetic pole 33 side. Thereby, it is possible to suppress the deterioration of the magnetic characteristics of the main magnetic pole 33 due to heat and to extend the life.
As a result, the influence of the near-field light R due to heat can be suppressed, and precise and efficient heat assist can be performed by the near-field light R. Moreover, since it is a simple structure which only provides the notch part 24d, it can implement | achieve the lifetime improvement, after suppressing the increase in manufacturing cost.

(Modification)
As shown in FIG. 18, the recording / reproducing head 250 having the concave curved surface 23c in the modified example of the second embodiment described above may be provided with a notch.
In this case, since the exposed portion 23f is previously formed in a concave shape with respect to the distal end side cladding 24b, the distance between the near-field light generating element 26 and the main magnetic pole 33 is the same as in the modification of the second embodiment described above. The thickness of the base end side cladding 23a can be reduced without changing d0. Therefore, the length of the recording / reproducing head 250 in the X direction can be shortened and the size can be reduced.

The technical scope of the present invention is not limited to the above-described embodiments, and includes those in which various modifications are made to the above-described embodiments without departing from the spirit of the present invention. In other words, the configuration described in the above-described embodiment is merely an example, and can be changed as appropriate.
For example, in the above-described embodiment, the air floating type information recording / reproducing apparatus in which the recording / reproducing head is levitated has been described as an example. However, the present invention is not limited to this case. The reproducing head may be in contact. That is, the recording / reproducing head of the present invention may be a contact slider type recording / reproducing head. Even in this case, the same effects can be achieved.

In the third embodiment, it is not necessary to form the entire core 23 on a curved surface, and only the exposed portion 23 f may be curved or protruded toward the main magnetic pole 33.
In the embodiment described above, the temperature of the core 23 can be adjusted by controlling the light intensity of the laser light L incident on the core 23, and the degree of thermal expansion of the core 23 (exposed portion 23f) can also be adjusted. It is. As a result, it is possible to control the distance d1 between the near-field light generating element 26 and the main magnetic pole 33 during recording and reproduction. That is, the near-field light generating element 26 can be freely brought close to the main magnetic pole 33 for the convenience of recording, so that heat assist can be accurately and efficiently performed at a desired position with respect to the main magnetic pole 33. The magnetic recording density can be improved. Further, since the structure is simple with only light intensity control, it is possible to extend the service life while suppressing an increase in cost.

  The case where the core 23 of the light beam propagation element 25 is gradually drawn from one end side to the other end side is described as an example. However, the present invention is not limited to this, and the core 23 may be formed straight. Further, although the light flux propagation element 25 in which the core 23 and the clad 24 are integrally formed of different materials has been described as an example, it may be formed in a hollow shape. In this case, the hollow air portion becomes the core and the portion surrounding the periphery becomes the cladding. Even in the light beam propagation element configured as described above, the laser light L can be propagated and incident on the near-field light generating element 26.

In the above-described embodiment, the case where the light propagation element is formed from the reproducing element 22 side has been described. However, the present invention is not limited to this, and the light propagation element may be formed from the recording element 21 side. In this case, a base end side clad (first clad) is formed on the main magnetic pole 33 of the recording element 21, and a concave portion is formed in the base end side clad. Then, a core having a curved surface on the reproducing element side can be formed by filling the recess with a core material. Thereafter, the front end side cladding (second clad) and the near-field light generating element are formed, and the reproducing element 22 is formed on the front end side cladding.
Also in this configuration, the formation surface of the near-field light generating element can be formed as a curved surface, so that near-field light with high light intensity can be generated.

Further, in the above-described embodiment, the case where the resin material is used for the light propagation element has been described. However, the present invention is not limited thereto, and quartz, tantalum oxide silicon, or the like may be used.
In the above-described embodiment, the case where the recording / reproducing head 2 of the present invention is employed in a perpendicular magnetic recording system that applies a recording magnetic field perpendicular to the disk D has been described. You may employ | adopt for the in-plane recording system which gives a horizontal recording magnetic field.

DESCRIPTION OF SYMBOLS 1 ... Information recording / reproducing apparatus 2,100,150,200,250 ... Recording / reproducing head (near-field optical head) 3 ... Beam 5 ... Actuator 6 ... Spindle motor (rotation drive part) 8 ... Control part 20 ... Slider 21 ... Recording Element 23 ... Core 24 ... Cladding 24a ... Proximal side cladding (second cladding) 24b ... Tip side cladding (first cladding) 24c ... Recess 24d ... Notch 25 ... Light flux propagation element 26 ... Near-field light generating element 43 ... Laser light source (light source) 50 ... Core material 50a ... Curved surface (exposed surface) D ... Disk (magnetic recording medium)

Claims (6)

A light flux propagation element that propagates a light flux toward the magnetic recording medium rotating in a certain direction;
A near-field light generating element for generating near-field light from the luminous flux to the magnetic recording medium side;
A recording element that applies a recording magnetic field to the magnetic recording medium,
A method of manufacturing a near-field optical head that records information by heating the magnetic recording medium with the near-field light and applying the recording magnetic field to the magnetic recording medium to cause magnetization reversal,
The light flux propagation element includes a core that guides the light flux in the direction of the magnetic recording medium while reflecting the light flux, and a first clad and a second clad that are sealed so as to sandwich the core.
A first cladding forming step of forming the first cladding;
A recess forming step of forming a recess along a thickness direction on a surface of the first cladding on which the second cladding is disposed;
A core forming step of forming the core in the recess;
A near-field light generating element forming step of forming the near-field light generating element on the exposed surface of the core formed in the recess;
A second clad forming step of laminating the second clad on the surface side of the first clad so as to seal the core;
A recording element disposing step of disposing the recording element on the opposite side of the core with the second cladding interposed therebetween,
The core forming step includes
A filling step of filling the liquid core material into the recess so that the exposed surface of the core material is curved with respect to the opening surface of the recess by surface tension with the recess;
And a curing step of curing the core material to form the core having a curved surface that is curved with respect to the opening surface.   2. The near-field light according to claim 1, wherein the filling step includes a surface tension adjusting step of adjusting a surface tension of the core material with the concave portion by adjusting a temperature of the core material. Manufacturing method of the head.   3. The method of manufacturing a near-field optical head according to claim 2, wherein, in the surface tension adjusting step, the exposed surface of the core material is curved in a convex shape with respect to the opening surface.   3. The method of manufacturing a near-field optical head according to claim 2, wherein, in the surface tension adjustment step, the exposed surface of the core material is curved in a concave shape with respect to the opening surface. In the near-field optical head manufactured using the manufacturing method of the near-field optical head according to any one of claims 1 to 4,
The near-field optical head according to claim 1, wherein the curved surface is curved to be concave with respect to the opening surface. A near-field optical head according to claim 5;
The near-field optical head is supported on the front end side so as to be movable in a direction parallel to the surface of the magnetic recording medium and rotatable about two axes parallel to the surface of the magnetic recording medium and orthogonal to each other. With the beam,
A light source that causes the light beam to enter the light beam propagation element;
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 control unit that controls the operation of the light source.

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