WO2008062676A1 - Proximity field light generation element, proximity field light head, and information recording/reproducing device - Google Patents

Abstract

A proximity field light generation element (22) includes a polyhedral core (40) and a clad (41) for covering the core in such a manner that the clad is in contact with the side surfaces of the core (40). The polyhedral core (40) has: a reflection surface (40a) for reflecting a light flux (L) in a direction different from the direction of introduction; a light flux collecting unit (40b) which is narrow-molded into such a shape that a cross sectional area orthogonally intersecting the longitudinal direction from one end to the other end is gradually reduced so as to collect the reflected light flux to propagate to the other end side; and a proximity field light generation unit (40c) which is further narrow-molded from the end of the light flux collecting unit to the other end side so as to generate a proximity field light (R) from the collected light and emit it outside from the other end side. An end surface (40d) has a size not greater than the wavelength of the light and the side surface of the proximity field light generation unit is shaded by a light-shading film (42).

Description

 Specification

 Near-field light generating element, near-field light head, and information recording / reproducing apparatus

 Technical field

 The present invention relates to a near-field light generating element that condenses an introduced light beam and generates near-field light from the light beam, and magnetic recording using the near-field light generated by the near-field light generating element The present invention relates to a near-field optical head for recording various kinds of information on a medium at an ultra-high density and an information recording / reproducing apparatus having the near-field optical head.

 Background art

 In recent years, the recording density of information within a single recording surface has increased with an increase in the capacity of hard disks and the like in computer equipment. 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 force recording density increases, the recording area occupied by one bit on the recording medium decreases. When this bit size is reduced, the energy power of 1-bit information is close to the thermal energy at room temperature, and the recorded demagnetization problem may be reversed or lost due to thermal fluctuations. It will occur.

 In a generally used in-plane recording method, force is a method for recording magnetism so that the direction of magnetization is in the in-plane direction of the recording medium. In this method, the recording information by thermal demagnetization described above is recorded. Disappearance 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 in a perpendicular magnetic field is easy to maintain in energy stability because it is difficult for the N and S poles to form a loop in the recording film plane. Therefore, this perpendicular recording method is more resistant to thermal demagnetization than the in-plane recording method!

[0004] However, recent recording media are required to have higher density in response to the need to record and reproduce a larger amount of high-density information. Therefore, in order to minimize the influence of adjacent magnetic domains and thermal fluctuations, a recording medium with a strong coercive force is used. Has begun to be adopted. Therefore, it has been difficult to record information on a recording medium even with the above-described perpendicular recording method.

 [0005] Therefore, in order to solve this problem, a hybrid magnetic recording method (near-field light assisted magnetism) 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. Recording system). This hybrid magnetic recording system uses near-field light generated by the interaction between a microscopic area and an optical aperture formed in a size smaller than the wavelength of the light formed in the near-field optical head. In this way, by using a small optical aperture that exceeds the diffraction limit of light, that is, a near-field optical head having a near-field light generating element, it is less than the wavelength of light that has been limited by conventional optical systems. It is possible to handle the optical information in the area. Therefore, it is possible to increase the density of recording bits exceeding the conventional optical information recording / reproducing apparatus.

 [0006] Note that the near-field light generating element may be constituted by a protrusion formed in a nanometer size, for example, not only by the above-described optical micro-aperture. This projection can also generate near-field light as in the case of the optical minute aperture.

 [0007] Various types of recording heads using the hybrid magnetic recording system described above are provided, and one of them is a near-field in which the recording density is increased by reducing the size of the light spot. Optical heads are known (see, for example, JP 2004-158067 and JP 2005 4901).

 [0008] This near-field optical head generates near-field light mainly from a main magnetic pole, an auxiliary magnetic pole, a coil winding in which a helical conductor pattern is formed inside an insulator, and irradiated laser light. A metal scatterer to be irradiated, a planar laser light source for irradiating the metal scatterer with laser light, and a lens for focusing the irradiated laser light. Each of these components is attached to the side surface of a slider fixed to the front end of the beam.

[0009] The main magnetic pole has one end facing the recording medium and the other end connected to the auxiliary magnetic pole. In other words, the main magnetic pole and the auxiliary magnetic pole 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 magnetic pole so that part of the coil winding passes between the magnetic pole and the auxiliary magnetic pole. These magnetic poles, auxiliary magnetic poles, and coil windings constitute an electromagnet as a whole! [0010] The metal scatterer made of gold or the like is attached to the tip of the main 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 side surface side of the slider.

 [0012] When the near-field light head configured as described above is used, various information can be recorded on the recording medium by generating a near-field light and simultaneously applying a recording magnetic field! .

 That is, laser light is emitted from a planar laser light source. This laser light is collected by a lens and irradiated onto a metal scatterer. Then, in the metal scatterer, the free electrons inside 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. As a result, the magnetic recording layer of the recording medium is locally heated by near-field light, and the coercive force temporarily decreases.

 [0014] Simultaneously with the laser light irradiation, a recording magnetic field is locally applied to the magnetic recording layer of the recording medium adjacent to the main pole by supplying a driving current to the conductor pattern of the coil winding. To do. As a result, it is possible to record various information on the magnetic recording layer whose coercive force is temporarily reduced. In other words, with the cooperation of near-field light and magnetic field, the recording force on the recording medium is controlled by the force S.

 Patent Document 1: Japanese Patent Application Laid-Open No. 2004_158067

 Patent Document 2: JP 2005-4901

 Disclosure of the invention

 Problems to be solved by the invention

However, the conventional near-field optical head described above still has the following problems.

That is, when generating near-field light indispensable for recording information, a laser beam is irradiated from a planar laser light source to the metal scatterer via the lens. However, since a metal scatterer was attached to the tip of the force main pole, it was inevitable to irradiate laser light obliquely from a planar laser light source. Therefore, the laser beam cannot be incident along the metal scatterer, and the laser beam is lost due to scattering or the like on the way, and the near-field light is generated efficiently. It was difficult. In particular, since the metal scatterer cannot intentionally change the direction of the introduced light, it has been forced to irradiate the laser beam obliquely and enter the metal scatterer as described above. .

 [0017] In addition, since it is necessary to dispose a lens between the planar laser light source and the metal scatterer in consideration of interference with the recording medium, a semicircular one is used. Therefore, it is difficult to efficiently focus the laser beam on the metal scatterer. This was also a factor in reducing the generation efficiency of near-field light.

 Means for solving the problem

[0018] The present invention has been made in view of such circumstances, and an object of the present invention is to efficiently collect near-field light by collecting light flux while changing the direction of the introduced light flux. It is possible to provide a near-field light generating element, a near-field light head having the near-field light generating element, and an information recording / reproducing apparatus having the near-field light head.

The present invention provides the following means in order to solve the above problems.

[0020] The near-field light generating element according to the present invention propagates the light beam introduced to one end side while condensing to the other end side in a direction different from the introduction direction, and generates the near-field light after generating the near-field light. A near-field light generating element that emits light at a reflection surface that reflects the introduced light flux in a direction different from the introduction direction, and a cross-sectional area perpendicular to the longitudinal direction from the one end side toward the other end side is gradually reduced. A light beam condensing unit that condenses and reflects the reflected light beam and propagates it toward the other end side, and further stops the end of the light beam condensing unit from the end to the other end side. A polyhedral core having a near-field light generating unit that generates the near-field light from the shaped and condensed light flux and emits the other-side force toward the outside, and has a refractive index higher than that of the core. In a state of being made of a low level material and with the other end of the core exposed to the outside The near-field light generating part has an end face exposed to the outside on the other end side having a size equal to or smaller than the wavelength of light, and has at least one side face. Is shielded from light by a light shielding film.

[0021] In the near-field light generating element according to the present invention, a polyhedral core formed integrally by the reflecting surface, the light beam condensing unit, and the near-field light generating unit, and a cladding for confining the core inside The near-field light from the other end side is introduced into the core from one end side. As outside] ¾ to be emitted by ¾.

 [0022] The clad is formed so as to be in close contact with the side surface of the core by a material having a refractive index lower than that of the core, and confines the core so that no gap is formed between the clad and the core. Here, when a light beam is introduced into the core from one end side, the light beam is reflected by the reflecting surface and changes its direction. That is, the direction changes in a direction different from the introduction direction. The light flux whose direction has been changed propagates in the core from one end side to the other end side by the light flux collecting section.

 [0023] At this time, the light beam condensing part is drawn so that the cross-sectional area perpendicular to the longitudinal direction from one end side to the other end side gradually decreases. Therefore, when the light beam passes through the light beam condensing portion, it is gradually condensed while repeating reflection on the side surface and propagates inside the core. In particular, since the clad is in close contact with the side surface of the core, light does not leak to the outside of the core, and the introduced light beam can be propagated to the other end side without being wasted.

 Then, the light beam propagated to the end of the light beam condensing unit is incident on the near-field light generating unit. This near-field light generating part is further drawn toward the other end, and the end face exposed to the outside at the other end is a size smaller than the wavelength of light (a minute size exceeding the light diffraction limit). It has become. However, at least one of the side surfaces of the near-field light generator is shielded by the light shielding film. Therefore, the light beam incident on the near-field light generating part can be propagated toward the end face without leaking to the clad side. Therefore, the force S that generates near-field light is the force S that is emitted from the edge surface force.

 As described above, the light beam introduced from one end side of the core can be converted into near-field light, and the near-field light can be emitted to the outside from the other end side. In addition, since the introduced light beam can be reflected by the reflecting surface and freely redirected toward the other end side, the light beam can be reliably introduced from the other end side in the near field regardless of the direction from which the light beam is introduced. The power S can be generated as light. Furthermore, since the light beam condensing part and the near-field light generating part are formed in a body-like manner, it is not necessary to align the positions as in the conventional lens and metal scatterer.

[0026] Because of these factors, the near-field light generating element can be easily used in various devices that require near-field light, and the degree of freedom in design can be improved. In particular, since near-field light can be generated efficiently regardless of the direction of light flux introduction, it is easy to handle and excellent in convenience. [0027] Further, the near-field light generating element according to the present invention is the near-field light generating element of the present invention, wherein the cladding force is formed with one end side of the core exposed to the outside. Is a special feature.

 In the near-field light generating element according to the present invention, since the clad is formed in a state where one end side of the core is exposed to the outside, it is possible to directly introduce the light flux into the core without passing through the clad. In addition, it can be converted into near-field light more efficiently and emitted from the end face to the outside.

 [0029] Further, in the near-field light generating element according to the present invention, in the near-field light generating element of the present invention, the near-field light generating unit has a predetermined length on the other end side that is the same as the end face. It is characterized by being shaped into a straight shape.

 [0030] In the near-field light generating element according to the present invention, the predetermined length on the other end side is not the end where the near-field light generating unit is not drawn from the end of the light beam condensing unit to the end surface. It is formed in a straight shape with the same size as the surface. Therefore, in the manufacturing process of the near-field light generating element, when the end surface is formed by dicing the other end side of the core and the clad, even if a small dicing error or a draw forming error occurs. The end face size can always be the same. Therefore, even if a large number of near-field light generating elements are manufactured, variations (individual differences) among the near-field light generating elements can be eliminated, and the same quality can be stably manufactured. Therefore, the yield can be improved.

 [0031] Further, in the near-field light generating element according to the present invention, in the near-field light generating element of any of the above-described present invention, all side surfaces of the near-field light generating unit are shielded from light by the light-shielding film. ! /, That is special.

 In the near-field generating element according to the present invention, since all the side surfaces of the near-field light generating unit are shielded by the light shielding film, the light beam incident on the near-field light generating unit leaks to the cladding side. There is no. Therefore, loss of light flux can be minimized, and near-field light can be generated more efficiently.

[0033] In the near-field light generating element according to the present invention, in the near-field light generating element of the present invention, the light shielding film is a metal film that increases the light intensity of the near-field light. It is that characteristic. In the near-field generating element according to the present invention, it is possible to generate a force S that generates near-field light having a higher light intensity. That is, the light beam collected by the light beam condensing unit is incident on the metal film by the near-field light generating unit. Then, surface plasmons are excited in this metal film. The excited surface plasmon propagates through the interface between the metal film and the core toward the end face while being enhanced by the resonance effect. And when it reaches the end face, it becomes near-field light with strong light intensity and leaks outside. In particular, since near-field light having a high light intensity can be generated at the interface between the metal film and the core, it is not directly affected by the design size of the end face itself. In other words, it is possible to reliably generate near-field light with a high light intensity that is not affected by the physical design, without having to make the end face size finer.

 [0035] Further, in the near-field light generating element according to the present invention, in the near-field light generating element of the present invention described above, the side surface of the near-field light generating portion provided with the metal film has the light flux collecting portion. The angle is adjusted so that the light beam condensed by the optical part is incident on the metal film at a resonance angle and the surface plasmon is excited by the energy of the light beam.

 In the near-field light generating element according to the present invention, the light beam condensed by the light beam condensing unit is incident on the metal film at a resonance angle at which the light energy is most utilized for excitation of the surface plasmon. Power S can be. Therefore, the surface plasmon can be excited most efficiently, and near-field light having a higher combing force and a higher light intensity can be generated. Therefore, further high density recording can be achieved.

[0037] Further, the near-field optical head according to the present invention heats the magnetic recording medium rotating in a certain direction and applies a recording magnetic field in the perpendicular direction to the magnetic recording medium, thereby causing magnetization reversal and information. A near-field optical head for recording a magnetic recording medium, a slider disposed opposite to the surface of the magnetic recording medium, an auxiliary magnetic pole fixed to the front end surface of the slider, and connected to the auxiliary magnetic pole via a magnetic circuit, A main magnetic pole that generates the recording magnetic field with the auxiliary magnetic pole, a coil that is supplied with a current modulated according to the information, and spirally wound around the magnetic circuit, and the other end side of the coil The near-field light generating element according to any one of the present invention, which is fixed adjacent to the main magnetic pole in a state facing the magnetic recording medium, and the slider arranged in parallel to the slider. Fixed and said one end It said from A light beam introducing means for introducing the light beam into the core, and the near-field light generating unit generates the near-field light in the vicinity of the main magnetic pole.

 In the near-field light head according to the present invention, the near-field light assisted magnetic recording method in which the near-field light generated by the near-field light generating element and the recording magnetic field generated by both magnetic poles cooperate with each other. Information can be recorded on the rotating magnetic recording medium.

 [0039] First, the slider is arranged in a state of facing the surface of the magnetic recording medium. An auxiliary magnetic pole is fixed to the front end surface of the slider, and a main magnetic pole is connected to the auxiliary magnetic pole via a magnetic circuit. Furthermore, a near-field light generating element is fixed adjacent to the main magnetic pole. That is, an auxiliary magnetic pole, a magnetic circuit, a main magnetic pole, and a near-field light generating element are arranged in this order from the slider side on the front end surface of the slider.

 In addition, the near-field light generating element is fixed in a state where the other end side where the near-field light is generated faces the magnetic recording medium side. Therefore, one end side where the light flux is introduced is directed to a position away from the magnetic recording medium. A light beam introducing means fixed to the slider is connected to one end side.

 [0041] When recording is performed here, the light beam is introduced into the core from the light beam introducing means. At this time, the light beam can be introduced in a direction parallel to the slider. Then, the introduced light beam is bent by approximately 90 degrees by the reflecting surface, and then propagates while being condensed by the light beam condensing unit toward the other end side located on the magnetic recording medium side. Then, near-field light is generated by the near-field light generation unit and leaks from the end face to the outside. The near-field light locally heats the magnetic recording medium and temporarily reduces the coercive force. In particular, the near-field light generator generates near-field light in the vicinity of the main magnetic pole, so that the coercivity of the magnetic recording medium can be reduced at a position as close as possible to the main magnetic pole.

On the other hand, simultaneously with the introduction of the light flux, a current modulated according to information to be recorded is supplied to the coil. Then, due to the electromagnet principle, the current magnetic field generates a magnetic flux in the magnetic circuit, so that a force S can be generated between the main magnetic pole and the auxiliary magnetic pole in a direction perpendicular to the magnetic recording medium. 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. As a result, the local position of the magnetic recording medium whose coercive force is reduced by near-field light is reduced. A recording magnetic field can be applied at a pinpoint. Note that the direction of this recording magnetic field is reversed according to the information to be recorded.

 Then, when the magnetic recording medium receives a recording magnetic field, the magnetization direction is reversed in the vertical direction in accordance with the direction of the recording magnetic field. As a result, information can be recorded. In other words, it is possible to record information by the near-field light assisted magnetic recording method in which the near-field light and the recording magnetic field cooperate. In addition, since recording is performed 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.

 [0044] In particular, since the coercive force of the magnetic recording medium can be reduced in the vicinity of the main magnetic pole, the peak position of the heating temperature can be set at a position where the recording magnetic field acts locally. Therefore, recording can be performed more reliably and high-density recording can be realized.

[0045] Further, since the near-field light generating element capable of efficiently generating near-field light is provided, the writing reliability of the near-field light head itself can be improved, and the quality can be improved. And force S. Further, since it is also a near-field light generating element that generates the light beam as near-field light from the other end side regardless of the direction from which the light beam is introduced, even if the light beam introducing means is arranged in parallel with the slider, the light beam The light beam from the introducing means can be made near-field light in the vicinity of the main magnetic pole. As described above, since the light beam introducing means can be arranged without being influenced by the direction of introducing the light beam, the design of the near-field optical head can be made compact. In addition, unlike the conventional way of entering light, there is no need to propagate the light beam in the air, so the light guide loss can be reduced as much as possible.

 [0046] Further, since the auxiliary magnetic pole, the main magnetic pole, the near-field light generating element, and the like are sequentially arranged on the leading end surface of the slider, it is possible to prevent as much as possible that each component other than the light beam introducing means overlaps in the slider thickness direction. is doing. Therefore, the near-field optical head itself can be thinned.

 [0047] Further, in the near-field optical head according to the present invention, a groove that exposes a side surface of the near-field light generating unit is formed in the clad in the near-field optical head of the present invention. In particular, the main magnetic pole force S and the protruding portion that comes into contact with the side surface of the near-field light generating portion through the groove portion are provided.

[0048] In the near-field optical head according to the present invention, the groove portion in which the main magnetic pole is formed in the cladding is provided. Since the projecting portion is in contact with the side surface of the near-field light generating portion, the position where the near-field light is generated and the position where the recording magnetic field is generated can be made as close as possible. Accordingly, the near-field light and the recording magnetic field can be made to cooperate more efficiently, and the force S can cope with the higher density recording.

 [0049] Further, the near-field optical head according to the present invention is the near-field optical head according to the present invention, wherein the light-shielding film is disposed between the protrusion and the side surface of the near-field light generating unit. Is formed.

 [0050] In the near-field light head according to the present invention, since the light shielding film is formed between the protrusion and the side surface of the near-field light generator, near-field light is generated more concentrated near the protrusion. The power to do S. Therefore, it is possible to achieve further high density recording.

 [0051] Further, the near-field optical head according to the present invention is the above-described contact-field optical head according to the present invention, wherein the protruding portion and the light-shielding film are electrically or magnetically connected. At least! /, A shield film that cuts off one of the connections is formed! /.

 In the near-field light head according to the present invention, information can be recorded by a near-field light-assisted magnetic recording method in which near-field light and a recording magnetic field are more effectively collaborated.

 [0053] Also, the information recording / reproducing apparatus according to the present invention is movable in the direction parallel to the surface of the magnetic recording medium and the! / A beam that supports the near-field light head on the tip side in a state of being rotatable about two axes that are parallel to the surface of the magnetic recording medium and perpendicular to each other, and the light beam is incident on the light beam introducing means A light source, 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, and a rotational drive for rotating the magnetic recording medium in the fixed direction And a controller for supplying the current to the coil and controlling the operation of the light source.

In the information recording / reproducing apparatus according to the present invention, after rotating the magnetic recording medium in a certain direction by the rotation drive 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 heads are parallel to the surface of the magnetic recording medium and orthogonal to each other. It is supported by the beam so that it can rotate about two axes, that is, it can be twisted about the two axes. Therefore, even if waviness occurs in the magnetic recording medium, changes in wind pressure due to waviness or waviness directly transmitted can be absorbed by twisting, and the attitude of the near-field optical head can be stabilized. it can.

[0055] Thereafter, the control unit activates the light source and supplies a current modulated according to the 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.

[0056] In particular, since the near-field optical head described above is provided, it is possible to cope with high-density recording with high writing reliability, and high quality can be achieved. At the same time, the power S is used to reduce the thickness.

 Brief Description of Drawings

 FIG. 1 is a configuration diagram showing an embodiment of an information recording / reproducing apparatus including a near-field light head having a near-field light generating element according to the present invention.

 2 is an enlarged cross-sectional view of the near-field optical head shown in FIG.

 FIG. 3 is a view of the near-field optical head shown in FIG. 2 as viewed from the disk surface side.

 4 is an enlarged cross-sectional view of the side surface on the outflow end side of the near-field light head shown in FIG. 2, showing the configurations of the near-field light generating element and the recording element, and the near-field light during recording. It is the figure which showed the relationship between and a magnetic field.

 FIG. 5 is a view of the core of the near-field light generating element shown in FIG. 4 as viewed from the direction of arrow A.

 FIG. 6 is an enlarged view of the other end side of the core shown in FIG.

 7 is an enlarged view of the other end side of the near-field light generating element shown in FIG.

 FIG. 8 is a view of the near-field light generating element shown in FIG. 7 as viewed from the end face side.

 FIG. 9 is a view showing a modification of the near-field light generating element according to the present invention, and is a view showing a core in which a part of the near-field light generating part is formed in a straight shape.

 10 is a cross-sectional view of the near-field light generating element having the core shown in FIG.

 FIG. 11 is a view of the near-field light generating element shown in FIG. 10 as viewed from the end face side.

FIG. 12 is a view showing a modification of the near-field light generating element according to the present invention, and is a cross-sectional view of the near-field light generating element in which a light shielding film is formed on all side surfaces of the near-field light generating part. 13] FIG. 13 is a view of the near-field light generating element shown in FIG. 12 as viewed from the end face side.

FIG. 14 is a diagram showing a modification of the near-field light generating element according to the present invention, in which a light-shielding film is formed on all side surfaces of the near-field light generating unit, and one of the light-shielding films is a metal film. 2 is a cross-sectional view of a near-field light generating element.

15] FIG. 15 is a view of the near-field light generating element shown in FIG.

 FIG. 16 is a view showing a modification of the near-field light generating element according to the present invention, and is a cross-sectional view of the near-field light generating element in which a metal film is formed on one of the side surfaces of the near-field light generating part. is there. 17] FIG. 17 is a view of the near-field light generating element shown in FIG. 16 as viewed from the end face side.

18] A diagram showing a modification of the near-field light head according to the present invention, and is a partially enlarged view of the near-field light head provided with the main magnetic pole in contact with the side surface of the near-field light generator.

19] FIG. 19 is a view of the near-field optical head shown in FIG. 18 as viewed from the end face side.

 FIG. 20 is a diagram showing a modification of the near-field light head according to the present invention, and a near-field light in which a light shielding film is formed between the main magnetic pole shown in FIG. 18 and the side surface of the near-field light generating unit. It is a partially enlarged view of the head.

En 21] FIG. 21 is a view of the near-field optical head shown in FIG. 20 as viewed from the end surface side.

22] A diagram showing a modification of the near-field optical head according to the present invention, and is a partially enlarged view of the near-field optical head using the light shielding film shown in FIG. 20 as a metal film.

En 23] FIG. 23 is a view of the near-field optical head shown in FIG. 22 as viewed from the end surface side.

 FIG. 24 is a view showing a modification of the near-field light head according to the present invention, and is one of the near-field light heads whose angle is adjusted on the side surface of the near-field light generating part on which the metal film shown in FIG. FIG.

25] FIG. 25 is a view of the near-field optical head shown in FIG. 24 as viewed from the end surface side.

 FIG. 26 is a diagram for explaining the relationship between the incident angle of light that excites surface plasmons and the intensity of reflected light.

FIG. 27 is a diagram showing a modification of the near-field optical head according to the present invention, and is a partially enlarged view of the near-field optical head in which a part of the metal film shown in FIG. 22 overlaps the clad.

En 28] FIG. 28 is a view of the near-field optical head shown in FIG. 27 as viewed from the end surface side.

29] A diagram showing a modification of the near-field optical head according to the present invention, wherein the metal shown in FIG. FIG. 4 is a partially enlarged view of a near-field optical head in which a shield film is formed between the film and the protrusion.

30 is a view of the near-field optical head shown in FIG. 29 as viewed from the end surface side.

 BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of a near-field light generating element, a near-field light head, and an information recording / reproducing apparatus according to the present invention will be described with reference to FIGS. 1 to 8. 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. In the present embodiment, an air floating type in which the near-field optical head 2 is floated using an air flow in which the disk D rotates will be described as an example.

 As shown in FIG. 1, the information recording / reproducing apparatus 1 of the present embodiment includes an optical near-field optical head 2 having a spot size converter (near-field light generating element) 22 described later, and a disk surface (magnetic The surface of the recording medium) The near-field optical head is movable in the X and Y directions parallel to D1 and is rotatable about two axes (X axis and Y axis) that are parallel to the disk surface D1 and perpendicular to each other. 2 that supports 2 on the distal end side, an optical signal controller (light source) 5 that makes the light beam L incident on the optical waveguide 4 from the proximal end side of the optical waveguide (flux introducing means) 4, and the proximal end of the beam 3 An actuator 6 that scans and moves the beam 3 in the XY directions parallel to the disk surface D1, a spindle motor (rotary drive unit) 7 that rotates the disk D in a fixed direction, and information. In response to this, a modulated current is supplied to the coil 33 described later. With a control unit 8 for controlling the operation of the optical signal controller 5, and a housings 9 that houses the respective components therein.

 [0060] The housing 9 is formed of a metal material such as aluminum in a square 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.

[0061] The spindle motor 7 is attached to the approximate center of the recess 9a, and the disc D is detachably fixed by fitting the center hole into the spindle motor 7. The above-mentioned actuator 6 is attached to the corner of the recess 9a. This actuator 6 has a shaft A carriage 11 is attached via a receiver 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.

 It should be noted that 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 controller 8 is attached adjacent to the actuator 6.

 [0063] The near-field optical head 2 heats the rotating disk D and applies a perpendicular recording magnetic field to the disk D to cause magnetization reversal and record information. As shown in FIGS. 2 and 3, the near-field optical head 2 is arranged so as to face the disk D in a state where it floats by a predetermined distance H from the disk surface D1, and has a slider 2 Oa facing the disk surface D1. 20, a recording element 21 fixed to the front end surface of the slider 20 (hereinafter referred to as a side surface on the outflow end side), a spot size converter 22 fixed adjacent to the recording element 21, An optical waveguide 4 for introducing a light beam L from the optical signal controller 5 is provided in a core 40 (to be described later) of the spot size converter 22. Further, the near-field light head 2 of the present embodiment includes a reproducing element 23 fixed adjacent to the spot size converter 22.

 [0064] The slider 20 is formed in a rectangular parallelepiped shape using a light-transmitting material such as quartz glass or a ceramic such as AlTiC (altic). The slider 20 is supported so as to hang from the tip of the beam 3 via the gimbal portion 24 with the opposing surface 20a facing the disk D. The gimbal portion 24 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 can be rotated around two axes (X axis, Y axis) that are parallel to the disk surface D1 and orthogonal to each other as described above.

The opposed surface 20a of the slider 20 is formed with a ridge portion 20b that generates pressure for rising due to the viscosity of the air flow generated by the rotating disk D. In the present embodiment, an example is given in which two ridges 20b extending in the longitudinal direction are formed so as to be arranged in a rail shape. However, not limited to this case, there is 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. As long as the slider 20 is designed to float in an optimal state by adjusting the height, any uneven shape may be used. The surface of this ridge portion 20b is a surface called ABS (Air Bearing Surface).

[0066] The slider 20 receives a force that rises from the disk surface D1 by the two ridges 20b. In addition, the beam 3 is steeped in the Z direction perpendicular to the disk surface D1, and absorbs the floating force of the slider 20. That is, the slider 20 receives a force pressed by the beam 3 to the disk surface D1 side 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. However, since the slider 20 is rotated about the X axis and the Y axis by the gimbal portion 24, the slider 20 always floats in a stable posture.

 [0067] Note that the air flow generated by the rotation of the disk D flows from the inflow end side (base end side of the beam 3) of the slider 20 and then flows along the ABS, and flows out along the outflow end side of the slider 20 (beam The tip of 3 is missing.

 As shown in FIG. 4, the recording element 21 is connected to the auxiliary magnetic pole 30 fixed to the side surface on the outflow end side of the slider 20 and the auxiliary magnetic pole 30 via the magnetic circuit 31, and is connected to the disk D. A main magnetic pole 32 that generates a perpendicular recording magnetic field with the auxiliary magnetic pole 30, and a coil 33 that spirally winds around the magnetic circuit 31 around the magnetic circuit 31. That is, the auxiliary magnetic pole 30, the magnetic circuit 31, the coil 33, and the main magnetic pole 32 are arranged in order from the outflow end side of the slider 20.

[0069] Both the magnetic poles 30, 32 and the magnetic circuit 31 are formed of a high saturation magnetic flux density (Bs) material (for example, CoNiFe alloy, CoFe alloy, etc.) having a high magnetic flux density. In addition, the coil 33 is arranged so that there is a gap between adjacent coil wires, between the magnetic circuit 31 and between the magnetic poles 30 and 32 so as not to be short-circuited. Molded by 34. The coil 33 is supplied with a current modulated in accordance with information from the control unit 8. That is, the magnetic circuit 31 and the coil 33 constitute an electromagnet as a whole. The main magnetic pole 32 and the auxiliary magnetic pole 30 are designed so that the end surfaces facing the disk D are flush with the ABS of the slider 20. As shown in FIGS. 4 and 5, the spot size converter 22 is adjacent to the recording element 21 with one end side facing the upper side of the slider 20 and the other end side facing the disk D side. Is fixed. More specifically, it is fixed adjacent to the main pole 32. FIG. 5 is a view of a core 40 described later as seen from the direction of arrow A shown in FIG.

 [0071] The spot size converter 22 propagates the light flux L introduced to one end side while condensing to the other end side in a direction different from the introduction direction, and generates the near-field light R and then emits it to the outside. As shown in FIGS. 4 to 8, the element is composed of a polyhedral core 40 and a clad 41 for confining the core 40 therein, and is formed in a substantially plate shape as a whole.

 FIG. 6 is an enlarged view of the other end side of the core 40 shown in FIG. 5, FIG. 7 is an enlarged view of the other end side of the spot size converter 22 shown in FIG. 4, and FIG. FIG. 8 is a view of the spot size converter 22 shown in FIG. 7 as viewed from the end face 40d side.

 [0073] The core 40 is integrally formed by the reflecting surface 40a, the light beam condensing unit 40b, and the near-field light generating unit 40c. In the present embodiment, the light beam condensing unit 40b and the near-field light generating unit 40c are each formed to have three side surfaces, and one of the side surfaces is arranged to face the main magnetic pole 32. It's like! /

 [0074] The reflection surface 40a reflects the light beam L introduced by the optical waveguide 4 from one end side in a direction different from the introduction direction. In the present embodiment, the light beam L is reflected so that the direction of the light beam L changes by approximately 90 degrees. The light beam condensing part 40b is a part formed by drawing so that the cross-sectional area perpendicular to the longitudinal direction (Z direction) from one end side to the other end side is gradually reduced, and is reflected by the reflecting surface 40a. The light beam L is condensed and propagated toward the other end. In other words, the light beam condensing unit 40b can reduce the spot size of the introduced light beam L to a small size.

[0075] The near-field light generating unit 40c is a portion that is further formed into a diaphragm from the end of the light beam condensing unit 40b toward the other end. That is, the near-field light generation unit 40c can further reduce the spot size narrowed down by the light beam condensing unit 40b. At this time, as shown in FIG. 8, the near-field light generating unit 40c is drawn so that the end face 40d located on the other end side has a size equal to or smaller than the wavelength of light. In other words, the maximum linear length L1 1S that can be secured on the end face 40d is designed to be less than the wavelength of the light. The size of this light is less than the wavelength. In particular, it is preferably in the range of lnm; m, and more preferably in the range of lnm force, 500 nm.

 [0076] As a result, the spot size can be reduced to the same size as the maximum linear length L1, that is, the diameter can be reduced to about In m to l ^ m (or about l nm to 500 nm). It can be emitted from the end face 40d to the outside as the incident light R.

 In the present embodiment, the light beam condensing unit 40b and the near-field light generating unit 40c are both gradually drawn toward the main magnetic pole 32 as shown in FIG. As a result, the end face 40d is positioned on the main magnetic pole 32 side. As a result, the near-field light R having the above size can be generated in the vicinity of the main magnetic pole 32. The term “near” in the present invention refers to a region within a range separated from the main magnetic pole 32 by a distance approximately equal to or less than the diameter of the near-field light R generated from the end face 40d. Therefore, in the present embodiment, the distance force between the main magnetic pole 32 and the end face 40d of the near-field light generator 40c is approximately the same as the diameter (maximum linear length L1) of the near-field light R from lnm to l ^ m It is designed to be a distance (or about lnm to 500nm) or less!

 As shown in FIGS. 4 and 5, the clad 41 is formed of a material having a refractive index lower than that of the core 40. The clad 41 is in close contact with the side surface of the core 40 to confine the core 40 inside. Yes. Therefore, there is no gap between the core 40 and the clad 41. Further, the clad 41 of the present embodiment is formed so that the end face 40d on the other end side is also exposed to the outside, like the one end side of the core 40.

 [0079] An example of a combination of materials used as the clad 41 and the core 40 is described. For example, a combination in which the core 40 is formed of quartz (SiO 2), and the clad 41 is formed of quartz doped with fluorine. Can be considered. In this case, when the wavelength of the light beam L is 400 nm, the refractive index of the core 40 is 1.47, and the refractive index of the clad 41 is less than 1.47, which is a preferable combination. A combination in which the core 40 is formed of quartz doped with germanium and the cladding 41 is formed of quartz (SiO 2) is also conceivable. In this case, when the wavelength of the light beam L is 4 OOnm, it becomes larger than the refractive skew force 1.47 of the core 40 and becomes the refractive skew force 47 of the clad 41.

[0080] In particular, the larger the refractive index difference between the core 40 and the clad 41, the more confined the light flux L in the core 40. Therefore, the tantalum oxide (TaO: refractive index 2.16 when the wavelength is 550 nm) is used for the core 40 and quartz is used for the clad 41 to increase the difference in refractive index between the two. More preferably. In addition, when the luminous flux L in the infrared region is used, it is also effective to form the core 40 with silicon (Si: refractive index is about 4) which is a material transparent to infrared light.

 In addition, a light shielding film 42 that shields the light flux L is formed on two of the three side surfaces of the near-field light generating unit 40c except for one side surface that faces the main magnetic pole 32. This prevents the light flux L from leaking from the near-field light generating unit 40c to the clad 41 side. The near-field light generating unit 40c generates near-field light R from the light beam L collected by the light beam condensing unit 40b and emits it from the end face 40d to the outside by the light shielding film 42 and the above-described aperture forming. It can be done. However, since the end face 40d is formed on the main magnetic pole 32 side, the near-field light R can be generated in the vicinity of the main magnetic pole 32. The end surface 40d of the spot size converter 22 is designed to be flush with the ABS of the slider 20.

 As shown in FIGS. 4 and 5, the optical waveguide 4 is a biaxial waveguide composed of a core 4a and a clad 4b, and the light flux L propagates through the core 4a. The optical waveguide 4 is fixed in a state of being fitted in a groove portion 41 a formed in the clad 41 and a groove portion (not shown) formed in the upper surface of the slider 20. As a result, the optical waveguide 4 is placed in parallel with the slider 20.

 Further, the tip end of the optical waveguide 4 is connected to one end side of the spot size converter 22, and the light flux L is introduced into the core 40. Further, the base end side of the optical waveguide 4 is drawn out to the optical signal controller 5 through the beam 3 and the carriage 11 and then connected to the optical signal controller 5.

 As shown in FIG. 5, the positions of the spot size converter 22 and the optical waveguide 4 are arranged so that the light beam L introduced from the optical waveguide 4 into the core 40 enters the approximate center of the reflecting surface 40a. The relationship has been adjusted.

Further, the reproducing element 23 is a magnetoresistive film whose electric resistance is converted according to the magnitude of the magnetic field leaking from the perpendicular recording layer d2 of the disk D. A bias current is supplied to the reproducing element 23 from the control unit 8 via a lead film (not shown). As a result, the control unit 8 detects a change in the magnetic field leaking from the disk D as a change in voltage. The signal can be reproduced from the change in voltage.

 Note that the disk D of the present embodiment is composed of at least two layers: a perpendicular recording layer d2 having an easy axis of magnetization in a direction perpendicular to the disk surface D1, and a soft magnetic layer d3 made of a high permeability material. Use vertical double-layer discs. 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 dl. Use the film.

 [0087] The substrate dl is, for example, an aluminum substrate or a glass substrate. The soft magnetic layer d3 is a high 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.

 Next, the case where various kinds of information is recorded / reproduced on / from the disk D by the information recording / reproducing apparatus 1 configured as described above will be described below.

 [0089] First, the spindle motor 7 is driven to rotate the disk D in a certain direction. Next, the actuator 6 is actuated to scan the beam 3 in the XY directions via the carriage 11. As a result, as shown in FIG. 1, a force S for positioning the near-field optical head 2 at a desired position on the disk D can be achieved. At this time, the near-field optical 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 side with a predetermined force by the beam 3 or the like. Attached. The near-field optical head 2 floats to a position separated from the disk D by a predetermined distance H as shown in FIG.

 In addition, even when the near-field optical 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 the gimbal portion 24 rotates around the XY axis. Therefore, it is possible to absorb the wind pressure caused by the swell. Therefore, the near-field optical 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 in accordance with the information to the coil 33. First, 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 core 4a of the optical waveguide 4 and is introduced into the core 40 from one end side of the spot size converter 22, as shown in FIG. At this time, the light beam L is introduced into the core 40 in a direction parallel to the slider 20. Then, the introduced light beam L is reflected by the reflecting surface 40a and changes its direction by approximately 90 degrees. That is, the direction changes in a direction different from the introduction direction. Then, the light beam L whose direction has changed is propagated while being collected by the light beam condensing unit 40b toward the other end side located on the disk D side, and is incident on the near-field light generating unit 40c.

 [0093] At this time, the light beam condensing part 40b is drawn so that the direction force from one end side to the other end side and the cross-sectional area perpendicular to the longitudinal direction gradually decrease. Therefore, when the light beam L passes through the light beam condensing part 40b, it is gradually condensed while being reflected on the side surface and propagates inside the core 40. In particular, since the clad 41 is in close contact with the side surface of the core 40, it is possible to propagate the introduced light flux L to the other end side without losing the introduced light flux L without leaking light to the outside of the core 40. Touch with S.

 Then, the light beam L propagated to the end of the light beam condensing unit 40b is incident on the near-field light generating unit 40c. The near-field light generation unit 40c is further drawn toward the other end, and the end surface 40d has a size equal to or smaller than the light wavelength. However, the two side surfaces of the near-field light generating unit 40c are shielded from light by the light shielding film 42. Therefore, the light beam L incident on the near-field light generating unit 40c can be propagated toward the end face 40d without leaking to the clad 41 side. Therefore, the near-field light R can be generated, and the near-field light R is emitted from the end face 40d.

 The near-field light R causes the disk D to be heated locally, and the coercive force is temporarily reduced. In particular, the near-field light generation unit 40c generates the near-field light R in the vicinity of the main magnetic pole 32, that is, in a range separated from the main magnetic pole 32 by a distance approximately equal to the diameter of the near-field light R. The coercive force of disk D can be reduced as close as possible to the main pole 32.

On the other hand, when a current is supplied to the coil 33 by the control unit 8, the current magnetic field generates a magnetic field in the magnetic circuit 31 according to the principle of the electromagnet, so that the demagnetization between the main magnetic pole 32 and the auxiliary magnetic pole 30 occurs. A recording magnetic field perpendicular to the disk D can be generated. Then, the magnetic flux generated from the main magnetic pole 32 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 in which the magnetization of the perpendicular recording layer d2 is directed perpendicular to the disk surface D1. Further, the magnetic flux reaching the soft magnetic layer d3 returns to the auxiliary magnetic pole 30 via the soft magnetic layer d3. At this time, when returning to the auxiliary magnetic pole 30, the direction of magnetization is not affected. This is because the area force of the auxiliary magnetic pole 30 facing the disk surface D1 is larger than the main magnetic pole 32, 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 32 side.

 As a result, information can be recorded by a near-field light assisted magnetic recording method in which the near-field light R and the recording magnetic fields generated by the magnetic poles 30 and 32 cooperate with each other. In addition, since recording is performed by the perpendicular recording method, stable recording that is hardly affected by the thermal fluctuation phenomenon or the like can be performed. Therefore, writing reliability can be improved.

 In particular, since the coercive force of the disk D can be reduced in the vicinity of the main magnetic pole 32, the peak position of the heating temperature can be set at a position where the recording magnetic field acts locally. Therefore, recording can be performed reliably, reliability can be improved, and high density recording can be achieved with the power S.

 Next, when reproducing the information recorded on the disc D, the reproducing element 23 fixed adjacent to the spot size converter 22 leaks from the perpendicular recording layer d2 of the disc D. In response to a magnetic field, the electrical resistance changes according to the magnitude. Therefore, the voltage of the reproducing element 23 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. The control unit 8 can reproduce information by reproducing the signal from the change in voltage.

[0100] As described above, the near-field optical head 2 of the present embodiment includes the spot size converter 22 that can generate the near-field light R efficiently! 2 The reliability of writing itself can be improved and the quality can be improved. In addition, in the present embodiment, the clad 41 is formed with the end face 40d on one end side and the other end side of the core 40 exposed to the outside, so that the light flux L is directly applied to the core 40 without passing through the clad 41. Can be introduced, and more efficiently converted to near-field light R and emitted from the end face 40d to the outside. Can do.

 [0101] In particular, since the spot size converter 22 can freely change the direction of the introduced light beam L by reflecting it with the reflecting surface 40a, even if the optical waveguide 4 is arranged parallel to the slider 20, The light beam L from the optical waveguide 4 can be converted into near-field light R in the vicinity of the main magnetic pole 32. Therefore, the optical waveguide 4 can be arranged without being affected by the direction in which the light flux L is introduced. Therefore, the design of the near-field optical head 2 can be made compact. Moreover, unlike the conventional way of entering light, it is not necessary to propagate the light beam L in the air, so that the light guide loss can be reduced as much as possible. Furthermore, since the recording element 21, the spot size converter 22 and the reproducing element 23 are arranged in this order on the side surface on the outflow end side of the slider 20, each component other than the optical waveguide 4 overlaps in the thickness direction of the slider 20. To prevent that. Therefore, it is possible to reduce the thickness of the near-field optical head 2 itself with the force S.

 [0102] Further, when the near-field optical head 2 of the present embodiment is manufactured, it can be manufactured by using a semiconductor technology such as a photolithography technology and an etching processing technology. That is

Even if the spot size converter 22 is provided, the spot size converter 22 can be created at the same time in the flow of the conventional manufacturing process without using a special method.

More specifically, after the slider 20 is processed into a predetermined outer shape, the recording element 21 is formed on the side surface on the outflow end side of the slider 20 using the semiconductor technology. Next, a spot size converter 22 is formed on the recording element 21 in the same manner using semiconductor technology. Finally, the reproducing element 23 may be built on the spot size converter 22. As described above, the near-field optical head 2 can be easily manufactured by adding only one manufacturing process of the spot size converter 22 in the course of manufacturing each component in order from the slider 20 side.

Note that when manufacturing the spot size converter 22, first, the cladding 41 is formed on the main magnetic pole 32. At this time, in order to connect the optical waveguide 4 to one end side later, the clad 41 is patterned so that the groove 41a is formed. Next, after the core 40 is formed in a convex shape on the clad 41, etching is performed as appropriate to form the reflecting surface 40a, the light beam condensing unit 40b, and the near-field light generating unit 40c. Next, light is blocked on the side surface of the near-field light generating unit 40c. A film 42 is formed. Next, the clad 41 is formed again so as to confine the core 40 inside. Finally, the outer shape of the clad 41 is processed into a predetermined shape. At this time, the end face 40d can be formed by cutting the other end side of the spot size converter 22 by dicing or the like. In this way, it is possible to easily manufacture the spot size converter 22 using semiconductor technology.

 [0105] Further, according to the information recording / reproducing apparatus 1 of the present embodiment, since the near-field optical head 2 described above is provided, it is possible to cope with high-density recording with high writing reliability. Ability to improve quality. At the same time, the thickness can be reduced.

 In the above-described embodiment, it is preferable to introduce the light beam L into the optical waveguide 4 after adjusting the polarization component of the light beam L in the arrow L2 direction shown in FIG. By doing this, the near-field light R can be concentrated and localized near the side surface (region S shown in FIG. 8) of the near-field light generation unit 40c facing the main magnetic pole 32 side. Therefore, it is possible to achieve higher density recording.

 It should be noted that the technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

 For example, in the above embodiment, the case where the spot size converter 22 is applied to the near-field light head 2 has been described as an example. However, the present invention is not limited to the near-field light head 2, and the near-field light R is not limited to the near-field light head 2. It may be applied to various necessary devices. In particular, in the above-described embodiment, when applied to the near-field light head 2, the introduced light beam L is designed to change its direction by approximately 90 degrees on the reflecting surface 40a, but the reflection angle is limited to this angle. is not. In other words, with the design of the reflecting surface 40a! /, The light beam L introduced from one end side can be reflected by the reflecting surface 40a and changed in direction toward the other end side at a free angle. Accordingly, the light flux L can be reliably generated as the near-field light R from the other end regardless of the direction from which the light flux is introduced. Therefore, it can be used for various devices that are easy to handle.

Further, in the above embodiment, as shown in FIGS. 9 to 11, the near-field light generating part 40c is formed so that the predetermined length L3 on the other end side is the same size as the end face 40d and is straight. It doesn't matter. That is, the predetermined length L3 on the other end side is not straight when the near-field light generating unit 40c is not drawn from the end of the light beam condensing unit 40b to the end surface 40d. It is formed in a shape.

 [0110] Therefore, in the manufacturing process of the spot size converter 22, when the other end side of the core 40 and the clad 41 is diced to form the end face 40d, a slight dicing error or a drawing molding error occurs. The end face 40d can always have the same size. Therefore, even if the spot size converters 22 are manufactured in large quantities, variations (individual differences) among the spot size converters 22 can be eliminated, and it is possible to stably manufacture products of the same quality. Therefore, the yield can be improved.

 [0111] In the above embodiment, only the two side surfaces of the three side surfaces of the near-field light generating unit 40c are shielded by the light-shielding film 42. At least one side surface may be shielded from light. Absent. Even in this case, the near-field light R can be generated.

 However, as shown in FIGS. 12 and 13, it is preferable that all the side surfaces (three side surfaces) be shielded by the light shielding film 42. By doing so, the light beam L incident on the near-field light generating unit 40c does not leak to the clad 41 side. Therefore, the loss of the luminous flux L can be minimized, and the near-field light R can be generated more efficiently.

 [0113] Furthermore, the light shielding film 42 formed on any one of the side surfaces may be a metal film 43 that enhances the light intensity of the near-field light R. For example, as shown in FIGS. 14 and 15, a light shielding film formed on the side surface facing the main magnetic pole 32 may be used as the metal film 43 that enhances the light intensity of the near-field light R. By doing so, near-field light R with higher light intensity can be generated. That is, the light beam L condensed by the light beam condensing unit 40b is incident on the metal film 43 by the near-field light generating unit 40c. Then, surface plasmons are excited in the metal film 43. The excited surface plasmon propagates toward the end face 40d through the interface between the metal film 43 and the core 40 while being enhanced by the resonance effect. And when it reaches the end face 40d, it leaks as near-field light R with high light intensity. Therefore, higher density recording can be achieved.

[0114] In particular, since the near-field light R having a high light intensity can be generated at the interface between the metal film 43 and the core 40, the design size of the end face 40d is not directly affected. In other words, the near-field light R having a high light intensity that is not affected by the physical design can be reliably generated without making the size of the end face 40d finer. [0115] The metal film 43 is, for example, a gold film, a silver film, a platinum film, or the like. Among these, it is preferable to use a gold film because it is resistant to oxidation and excellent in durability. It is also possible to use the light shielding film as the metal film 43! /

 [0116] Furthermore, the metal film 43 may be formed on only one or two of the three side surfaces of the near-field light generating unit 40c. For example, as shown in FIGS. 16 and 17, the metal film 43 may be formed on one of the three side surfaces of the near-field light generating unit 40c other than the side surface facing the main magnetic pole 32. . Even in this case, the force S can be generated in a state where the near-field light R having high light intensity is localized at the interface between the metal film 43 and the core 40 without being influenced by the physical design. Therefore, further high density recording can be achieved.

 [0117] In particular, since the metal film 43 is formed on only one of the three side surfaces of the near-field light generating unit 40c, it is easier to make compared with the case where the metal film 43 is formed on two or three side surfaces.

 Further, in the above embodiment, as shown in FIGS. 18 and 19, a groove 41b that exposes the side surface of the near-field light generating part 40c is formed in the clad 41, and the near field through the groove 41b. The main magnetic pole 32 may be provided with a protruding portion 32a that contacts the side surface of the light generating portion 40c.

 [0119] By doing this, the force S can be as close as possible to the position where the near-field light R is generated and the position where the recording magnetic field is generated. Therefore, the near-field light R and the recording magnetic field can be made to cooperate more efficiently, and this can be dealt with by high-density recording.

 [0120] In particular, when the protrusion 32a is provided, as shown in FIGS. 20 and 21, when the light-shielding film 42 is formed between the protrusion 32a and the side surface of the near-field light generator 40c. More preferred. By doing so, the near-field light R can be intensively generated in the vicinity of the projecting portion 32a, so that higher density recording can be achieved.

 Furthermore, when the protrusion 32a is provided, as shown in FIGS. 22 and 23, it is formed on the side surface facing the main magnetic pole 32 among the three side surfaces of the near-field light generating unit 40c. The light shielding film is preferably a metal film 43 as in the case shown in FIGS. By doing so, it is possible to generate force S with a strong light intensity and a near-field light R localized at a position near / to the protruding portion 32a. Therefore, the near-field light R and the recording magnetic field can be more efficiently collaborated, and higher density recording can be achieved.

[0122] Further, when the metal film 43 is provided as shown in FIG. 22 and FIG. It is possible to generate near-field light R with a higher light intensity.

[0123] For example, the light beam L collected by the light beam condensing unit 40b is incident on the metal film 43 at the resonance angle Θ, and surface plasmon is excited on the surface of the metal film 43 by the energy of the light beam L. As shown in FIGS. 24 and 25, the angle of the side surface of the near-field light generating unit 40c on which the metal film 43 is formed may be adjusted.

[0124] Here, the incident angle of the light beam L and the reflected light intensity will be briefly described.

As shown in FIG. 26, when the light L1 is incident on the prism P1 having the metal film P2 on the bottom surface under the total reflection condition, the incident angle Θ (a straight line perpendicular to the surface of the metal film P2 The reflected light intensity changes according to the angle formed with the light L1. This is because the energy of light L1 is used to excite surface plasmons. When the reflected light intensity is detected by changing the incident angle, there is an incident angle at which the reflected light intensity is minimized. This is because the energy of light L1 is most utilized for excitation of surface plasmons. The incident angle at which the reflected light intensity is minimized is generally referred to as the resonance angle.

Therefore, as shown in FIG. 24, surface plasmon can be excited most efficiently by making the light beam L collected by the light beam condensing unit 40b enter the metal film 43 at the resonance angle Θ. It is possible to generate near-field light R with higher efficiency and higher light intensity.

[0127] The light flux L introduced into the core 40 is gradually condensed while being reflected on the side surface of the core 40, and is gradually condensed and is advanced to the end face 40d. The direction to go is determined. That is, when the core 40 is designed, it is possible to grasp how the main component of the light flux L propagates through the core 40 while proceeding. Therefore, as shown in FIG. 24, the angle of the side surface of the near-field light generating unit 40c may be adjusted so that the main component of the light beam L is incident on the metal film 43 at the resonance angle Θ.

In addition, when the collected light beam L is incident on the metal film 43 at the resonance angle Θ, as shown in FIGS. 27 and 28, if the metal film 43 is designed to partially overlap the clad 41, good. As described above, it is known that the light beam L is incident on the metal film 43 at the resonance angle Θ, so that the surface plasmon is efficiently excited. Only the dielectric thin film is adsorbed on the metal film P2 of the prism P1. It is also generally known that the resonance angle Θ changes at. Therefore, as shown in FIG. 27, the metal film 43 and the clad 41 are partially overlapped so that the resonance angle Θ Can be adjusted in degrees. Therefore, even in the case shown in FIG. 27, it becomes possible to make the collected light beam L incident on the metal film 43 at the resonance angle Θ, and similarly, the near-field light R having a higher light intensity is more efficiently used. It can be generated well.

 [0129] In particular, even when it is difficult to mechanically adjust the angle of the side surface of the near-field light generating unit 40c, the resonance angle Θ itself can be changed, so that mechanical design can be assisted. The Therefore, the degree of freedom in design can be improved.

 Furthermore, when the metal film 43 is provided as shown in FIGS. 22 and 23, the shield film 44 shown in FIGS. 29 and 30 may be provided between the metal film 43 and the protruding portion 32a. I do not care. The shield film 44 blocks at least one of the electrical connection or the magnetic connection between the protrusion 42a and the metal film 43. In this way, it is possible to use the near-field light assisted magnetic recording method that more effectively collaborates the near-field light R and the recording magnetic field to achieve the ability to record information.

 Further, in each of the above embodiments, the air floating type information recording / reproducing apparatus 1 in which the near-field optical head 2 is levitated has been described as an example. However, the present invention is not limited to this and is directed to the disk surface D1. As long as it is arranged, the disk D and the slider 20 may be in contact with each other. That is, the near-field optical head 2 according to the present invention may be a contact slider type head! / Even in this case, the same effects can be achieved.

 Industrial applicability

 [0132] According to the near-field light generating element of the present invention, the light beam introduced from one end side of the core can be efficiently converted into near-field light, and the near-field light is externally transmitted from the other end side. Power S can be generated. In particular, the ability to generate near-field light efficiently regardless of the direction in which the light flux is introduced can be used, making it easy to handle and convenient. Therefore, it can be easily used for various devices that require near-field light, and the degree of design freedom can be improved.

[0133] Further, according to the near-field light head according to the present invention, since the near-field light generating element described above is provided, the writing reliability can be improved and the quality can be improved. In addition, since the light beam introduction means can be arranged without being influenced by the direction in which the light beam is introduced, it is possible to make the design compact. Moreover, unlike the conventional method of entering light, it is not necessary to propagate the light beam in the air, so that the light guide loss can be reduced as much as possible. Other than the light beam introducing means Each component is prevented from overlapping in the thickness direction of the slider as much as possible.

 Further, according to the information recording / reproducing apparatus of the present invention, since the near-field optical head described above is provided, it is possible to cope with high-density recording with high writing reliability, and to achieve high quality. Power S can be. At the same time, the thickness can be reduced.

Claims

The scope of the claims  [1] A near-field light generating element that propagates a light beam introduced to one end side while condensing to the other end side in a direction different from the introduction direction, and generates the near-field light and then emits it to the outside. The reflected light beam is reflected in a direction different from the introduction direction, and the cross-sectional area perpendicular to the longitudinal direction from the one end side to the other end side is gradually reduced and reflected. A light beam condensing part that propagates the light beam toward the other end side while condensing the light beam, and further drawn from the end of the light beam condensing part toward the other end side, and the proximity from the condensed light flux A polyhedral core having a near-field light generation unit that generates field light and emits the light from the other end side toward the outside;  A clad that is formed of a material having a refractive index lower than that of the core, tightly contacts the side of the core with the other end of the core exposed to the outside, and traps the core inside.  The near-field light generating unit is characterized in that an end surface exposed to the outside on the other end side has a size equal to or less than a wavelength of light, and at least one side surface is shielded by a light-shielding film. Generating element.  [2] The near-field light generating element according to claim 1! /,  The near-field light generating element, wherein the clad is formed with one end of the core exposed to the outside! /. [3] The near-field light generating element according to claim 1! /,  The near-field light generating element, wherein the near-field light generating part is formed in a straight shape with a predetermined length on the other end side being the same size as the end face. [4] The near-field light generating element according to claim 1! /,  All the side surfaces of the near-field light generating part are shielded by the light-shielding film, and the near-field light generating element is characterized in that: [5] The near-field light generating element according to claim 1! /,  The near-field light generating element, wherein the light-shielding film is a metal film that increases the light intensity of the near-field light. [6] The near-field light generating element according to claim 5, The metal film is provided! /, And the side surface of the near-field light generating unit is the light beam condensing unit. The near-field light generating element, wherein the condensed light beam is incident on the metal film at a resonance angle, and the surface plasmon is excited by the energy of the light beam.  [7] A magnetic recording medium rotating in a certain direction is heated, and a perpendicular recording magnetic field is applied to the magnetic recording medium to cause magnetization reversal, so that the near-field light is used to record information. And  A slider disposed opposite to the surface of the magnetic recording medium;  An auxiliary magnetic pole fixed to the front end surface of the slider;  A main magnetic pole connected to the auxiliary magnetic pole through a magnetic circuit and generating the recording magnetic field with the auxiliary magnetic pole;  A coil that is supplied with a current modulated according to the information and spirally wound around the magnetic circuit;  The near-field light generating element according to claim 1, wherein the near-field light generating element is fixed adjacent to the main magnetic pole with the other end side facing the magnetic recording medium side.  A light beam introducing means fixed to the slider in a state of being arranged in parallel to the slider and introducing the light beam into the core from the one end side;  The near-field light head is characterized in that the near-field light generator generates the near-field light in the vicinity of the main magnetic pole. [8] The near-field optical head according to claim 7,  The clad is formed with a groove that exposes the side surface of the near-field light generating unit, and the main magnetic pole has a protrusion that contacts the side surface of the near-field light generating unit via the groove. / Near-field optical head characterized by squeezing. [9] The near-field optical head according to claim 8,  A near-field light head, wherein the light shielding film is formed between the protruding portion and the side surface of the near-field light generating portion, and is V-shaped. [10] The near-field optical head according to claim 9, Between the protruding portion and the light shielding film, among the electrical or magnetic connection between them, A near-field optical head, characterized in that a shielding film that cuts off at least one of the connections is formed. The near-field optical head according to claim 7,  The near-field optical head can be moved 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. A supporting 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 control unit that supplies the current to the coil and controls the operation of the light source.