JP5397200B2 - Thermally assisted magnetic head and recording / reproducing apparatus - Google Patents

Description

  The present invention relates to a heat-assisted magnetic head capable of high-density magnetic recording and a recording / reproducing apparatus using the same.

  2. Description of the Related Art Conventionally, as a next-generation technology for an information recording / reproducing apparatus such as an HDD (Hard Disc Drive), a heat-assisted magnetic recording technology that performs high-density magnetic recording using light with a minute spot size has been developed. In this heat-assisted magnetic recording, in order to achieve high density recording, it is necessary to make the spot size of the light used smaller.

  As one technique for reducing the light spot size, a technique using a surface plasmon resonance phenomenon that occurs when a conductor is irradiated with propagating light has been proposed. In this method, minute light such as near-field light is generated at the end of the conductor due to the surface plasmon resonance phenomenon. Therefore, by generating near-field light using this method, it is possible to irradiate the recording medium with minute light having a minute spot size that could not be realized by a conventional optical system.

  In the above-described method, in order to generate a surface plasmon resonance phenomenon in the conductor to generate near-field light, the size of the conductor is set to about several tens to several hundreds of nm. In addition, when the target magnetic recording density is increased, it is necessary to further reduce the size of the end portion of the conductor that generates near-field light. In order to collect and irradiate light emitted from a light source such as an LD (laser diode), for example, to a conductor having a minute dimension at its end, it has good integration and high propagation efficiency. An optical system is required.

  In view of this, conventionally, various optical systems having good integration and high propagation efficiency have been proposed for thermally-assisted magnetic heads (see, for example, Patent Document 1). In Patent Document 1, an optical waveguide is created in the vicinity of the magnetic recording / reproducing head using a process similar to the manufacturing process of the magnetic recording / reproducing head, and a light source such as an LD is disposed near the entrance of the waveguide. A configuration is proposed.

JP 2008-59693 A

  As described above, in the optical system disclosed in Patent Document 1, a configuration in which an optical waveguide is provided between a light source and a magnetic recording / reproducing head has been proposed. However, such a configuration causes the following problems. There is a fear.

  First, if the size of the optical waveguide is made larger than the beam diameter of light emitted from a light source such as an LD, the coupling efficiency of light in the optical waveguide increases, but the light propagating in the optical waveguide becomes multimode, so the mode Interference occurs between them.

  If the waveguide length is about the same as or shorter than the wavelength, the light intensity distribution in the waveguide can be predicted even if there is some interference between modes. The shape of the emission port can be formed with high accuracy. However, when the waveguide length is relatively longer than the wavelength, it is difficult to predict the light intensity distribution in the waveguide, so that it is possible to obtain outgoing light having a stable wavefront at the exit of the optical waveguide. It becomes difficult. That is, there arises a problem that it becomes difficult to efficiently propagate light from the light source to the light irradiation element.

  The present invention has been made in view of the above problems. SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-assisted magnetic head and a recording / reproducing apparatus using the heat-assisted magnetic head that are excellent in integration (manufacturability) and efficiently transmit light from a light source to a light irradiation element. is there.

In order to solve the above-described problems, a thermally-assisted magnetic head according to the present invention includes an optical substrate, a first light collecting unit, a second light collecting unit, a light irradiation element, a waveguide, and a magnetic recording element. The configuration is as follows. The optical substrate has a condensing portion for condensing light from a light source incident from the side opposite to the medium facing surface side of the slider substrate formed on the surface of the slider substrate opposite to the medium facing surface side. Connected to the medium facing surface side. The first condensing unit is provided with a plurality of material layers having different refractive indexes on a side surface perpendicular to the medium facing surface of the slider substrate in a direction perpendicular to the side surface of the slider substrate. Is condensed in a direction perpendicular to the side surface of the slider substrate, and the condensed first light is emitted. The second condensing part is thinner than the thickness in the direction perpendicular to the side surface of the slider substrate of the first condensing unit on the side surface of the slider substrate and on the first light exit side of the first condensing unit. Provided in a direction orthogonal to the side surface of the slider substrate, the thickness in the direction orthogonal to the side surface of the slider substrate is constant, the incident surface of the first light is a convex curved surface, and is emitted from the first light collecting unit The first light is condensed in a direction parallel to the side surface of the slider substrate and perpendicular to the propagation direction of the first light, and the condensed second light is emitted. The light irradiation element is provided on the side surface of the slider substrate and on the second light emitting side of the second light collecting unit, and the recording light is applied to the recording medium by the second light emitted from the second light collecting unit. And the recording light is emitted. The waveguide is provided between the second light collecting unit and the light irradiation element on the side surface of the slider substrate, and guides the second light emitted from the second light collecting unit to the light irradiation element. The magnetic recording element is provided on the side surface of the slider substrate via an insulating layer with respect to the waveguide , generates a recording magnetic field, and applies the generated recording magnetic field to a region of the recording medium irradiated with the recording light. .

  The information recording apparatus of the present invention includes the above-described heat-assisted magnetic head of the present invention and a drive unit that drives the heat-assisted magnetic head.

As described above, in the thermally-assisted magnetic head of the present invention, in addition to the magnetic recording element and the light irradiation element, the optical substrate that condenses the light emitted from the light source by the condensing unit, and the light from the optical substrate. A first light collecting unit and a second light collecting unit having a function of collecting light in different directions, and a waveguide for guiding light from the second light collecting unit to the light irradiation element . Specifically, the optical substrate has a condensing part that collects light from a light source incident from the side opposite to the medium facing surface side of the slider substrate on the surface opposite to the medium facing surface side of the slider substrate. Formed and connected to the medium facing surface side of the slider substrate. The first condensing unit is provided with a plurality of material layers having different refractive indexes on a side surface perpendicular to the medium facing surface of the slider substrate in a direction perpendicular to the side surface of the slider substrate. From the slider substrate in a direction perpendicular to the side surface of the slider substrate. On the other hand, the second light condensing unit is thinner on the side surface of the slider substrate and on the first light exit side of the first light condensing unit than the thickness in the direction perpendicular to the side surface of the slider substrate of the first light condensing unit. The thickness of the first substrate is set in a direction orthogonal to the side surface of the slider substrate, the thickness in the direction orthogonal to the side surface of the slider substrate is constant, and the incident surface of the first light is a convex curved surface. Has a function of condensing the emitted light (first light) in a direction parallel to the side surface of the slider substrate and perpendicular to the propagation direction of the first light. That is, in the present invention, the light from the optical substrate is collected in two steps in different one-dimensional directions. Therefore, even when the above-described light source that emits light having a relatively large spot diameter, such as an LD, is used as the light source of the thermally assisted magnetic head, light having a light spot of a desired size can be easily irradiated with the light irradiation element. Can be introduced. As a result, in the present invention, the light collecting unit, the first light collecting unit, and the second light collecting unit can suppress a decrease in light utilization efficiency when light from the light source is introduced into the light irradiation element. .

  Further, since the first condensing part and the second condensing part are formed on the side surface orthogonal to the medium facing surface side of the slider substrate, the side surface of the slider substrate is utilized by utilizing the existing manufacturing process of the magnetic head element. A 1st condensing part and a 2nd condensing part can be manufactured easily on the top. For example, the first light collecting unit can be formed by sequentially laminating layers having different materials and shapes on the side surface of the slider substrate, and has a desired light collecting function in a direction perpendicular to the side surface of the slider substrate. The structure which has can be manufactured easily. In addition, the second light collecting unit, for example, applies a first light from the first light collecting unit in parallel with the side surface of the slider substrate and a first refractive index layer using a technique such as photolithography. It can be formed by patterning into a shape that condenses light in a direction orthogonal to the light propagation direction. In other words, in the present invention, the second light condensing part can also be easily manufactured on the side surface of the slider substrate.

  As described above, in the present invention, the first condensing part and the second condensing part can be easily formed on the side surface of the slider substrate, and the first condensing part and the second condensing part provide a light source. Can be efficiently propagated to the light irradiation element. Therefore, according to the present invention, there are provided a thermally assisted magnetic head that is excellent in integration (manufacturability) and can efficiently propagate light from a light source to a light irradiation element, and a recording / reproducing apparatus using the same. be able to.

1 is a schematic cross-sectional view of a thermally-assisted magnetic head according to a first embodiment of the present invention. It is a schematic plan view of the 2nd condensing part of the thermally assisted magnetic head which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating the condensing effect | action of the 1st and 2nd condensing part in the heat-assisted magnetic head which concerns on the 1st Embodiment of this invention. It is a schematic perspective view of the 1st condensing part of the thermally-assisted magnetic head which concerns on the 1st Embodiment of this invention. It is a figure which shows the light intensity distribution of the incident light at the time of using the 1st condensing part shown in FIG. 4, and the condensed light. FIG. 10 is a schematic cross-sectional view of a first light collecting unit in a heat-assisted magnetic head according to Modification 1. FIG. 10 is a schematic cross-sectional view of a first light collecting unit in a heat-assisted magnetic head according to Modification 2. FIG. 10 is a schematic plan view of a second light collecting unit in a heat-assisted magnetic head according to Modification 3. FIG. 10 is a schematic cross-sectional view of a heat-assisted magnetic head of modification example 4. FIG. 10 is a view for explaining the light condensing action of the first and second light converging parts in the heat-assisted magnetic head of Modification Example 5. FIG. 10 is a schematic plan view of first and second light collecting portions in an assist magnetic head according to Modification Example 5. It is a schematic perspective view of the recording / reproducing apparatus which concerns on the 2nd Embodiment of this invention. It is an enlarged side view of the vicinity of the flying slider of the recording / reproducing apparatus according to the second embodiment of the present invention.

The best mode for carrying out the present invention will be described below, but the present invention is not limited to the following examples. The description will be made in the following order.
1. First embodiment (thermally assisted magnetic head)
(1) Configuration of thermally assisted magnetic head (2) Description of light collecting action by first and second light collecting parts (3) Light collecting characteristic of first light collecting part Modified example of the first embodiment (thermally assisted magnetic head)
3. Second embodiment (recording / reproducing apparatus)

<1. First Embodiment (Heat Assisted Magnetic Head)>
As a technique for obtaining a stable wavefront by propagating light from a light source for a long distance in a waveguide, a technique for propagating light in a single mode in the waveguide can be considered. In this case, however, the core size of the waveguide is usually smaller than the spot size of light emitted from a light source such as an LD. For example, the core of the waveguide is formed of Ta ₂ O ₅ (n = 2.15), the surrounding cladding material is formed of Al ₂ O ₃ (n = 1.65), and the wavelength of incident light in the waveguide Is 850 nm, the core cross-sectional size is about 300 nm or less in order to propagate light in a single mode. On the other hand, the field shape of light emitted from a typical LD is about several μm.

  That is, there is a difference of about one digit between the core size of the single mode propagation path and the spot size of the light emitted from the light source. Therefore, when light from a light source such as an LD is directly incident on the optical waveguide, light that is not introduced into the core of the waveguide becomes radiated light as it is. In such direct coupling between the light source and the waveguide, the light utilization efficiency is greatly deteriorated. Therefore, when a single mode waveguide is used as the optical waveguide, a condensing means for condensing light from the light source and introducing it into the optical waveguide is required.

  Therefore, in the present embodiment, a configuration example of a heat-assisted magnetic head having such a light condensing function and having a structure that can be easily manufactured by a procedure of an existing manufacturing process will be described.

(1) Configuration of Thermally Assisted Magnetic Head FIG. 1 shows a schematic sectional configuration example of a thermally assisted magnetic head according to the first embodiment of the present invention. FIG. 1 illustrates a cross-sectional structure across the medium facing surface 2 and the side surface 3 of the slider substrate 1.

  The heat-assisted magnetic head 50 of the present embodiment is formed on the side 3 on the air outflow side that is substantially perpendicular to the medium facing surface 2 of the slider substrate 1, the so-called air bearing surface (hereinafter referred to as ABS surface). . Therefore, the surface opposite to the side surface 3 side of the thermally assisted magnetic head 50 formed on the side surface 3 is the trailing surface.

  In the example shown in FIG. 1, a light source such as a Fabry-Perot type LD or a surface emitting laser is provided on a surface opposite to the medium facing surface 2 of the slider substrate 1 via a connecting portion 61 made of, for example, an adhesive. A substrate 71 on which (not shown) is formed is provided. As the surface emitting laser, for example, a VCSEL (Vertically Cavity Surface Emitting LASER) can be used.

The slider substrate 1 is a plate-like member in which the medium facing surface 2 is processed into a predetermined shape. The shape of the medium facing surface 2 is such that, for example, when the slider substrate 1 travels at a predetermined speed relative to the surface of a recording medium such as a disk, the slider substrate 1 floats with an appropriate flying height. To be processed. As a material for forming the slider substrate 1, for example, ceramic such as AlTiC (Al ₂ O ₃ —TiC) is used.

  The heat-assisted magnetic head 50 includes a magnetic shield layer 5, a magnetic reproducing element 6, a return magnetic pole 8, a recording magnetic pole 10 (magnetic recording element), a waveguide 11, a coil 14, a light irradiation element 20, a first light collecting unit 30, It is comprised with the 2nd condensing part 40 and the insulating layer provided between each part.

  The heat-assisted magnetic head 50 is manufactured by laminating an insulating layer, a magnetic layer, and the like in a predetermined order on the side surface 3 of the slider substrate 1. In the example shown in FIG. 1, the left direction in the drawing is the stacking direction of the insulating layer, the magnetic layer, and the like. Specifically, for example, the heat-assisted magnetic head 50 can be manufactured by the following method. First, the insulating layer 4, the magnetic shield layer 5, and the insulating layer 7 are laminated in this order on the side surface 3 of the slider substrate 1, and the magnetic reproducing element 6 is formed at the end of the insulating layer 7 on the medium facing surface 2 side. . Next, the return magnetic pole 8 and the insulating layer 9 are laminated on the insulating layer 7 in this order. Then, the waveguide 11, the insulating layer 13, the coil 14, the recording magnetic pole 10, and the insulating layer 15 are laminated in this order on the insulating layer 9.

  At this time, the first light collecting portion 30 is formed by alternately laminating the high refractive index material layers 31 and the insulating layers at a predetermined interval on the light incident surface 51 side opposite to the medium facing surface 2. . Further, the second light collecting unit 40 is formed on the light incident surface 51 side of the waveguide 11 and is formed so as to be connected to the end of the waveguide 11 on the light incident surface 51 side. In the present embodiment, the heat-assisted magnetic head 50 is produced on the side surface 3 of the slider substrate 1 as described above.

  However, in the manufacturing process of the heat-assisted magnetic head 50, the recording magnetic pole 10 is formed so that a part thereof penetrates the insulating layer 13 and crosses the waveguide 11 and is connected to the return magnetic pole 8. At this time, the recording magnetic pole 10 is formed so as not to contact the waveguide 11. For example, a through hole is provided in one of the recording magnetic pole 10 and the waveguide 11, and one component part where no through hole is provided is formed in the through hole of the other component part via an insulating layer. For example, the waveguide 11 may be formed in a pattern that bypasses the recording magnetic pole 10. For example, the arrangement of the recording magnetic pole 10 and the waveguide 11 such as an arrangement relationship can be applied as long as it does not contact the recording magnetic pole 10 and the waveguide 11.

  In the manufacturing process of the heat-assisted magnetic head 50, the coil 14 embedded in the insulating layer 13 is formed so as to surround a part of the recording magnetic pole 10. The end of the recording magnetic pole 10 on the medium facing surface 2 side is formed so as to be positioned in the vicinity of the waveguide 11, and the film thickness of the end is made thinner than the film thickness of the other part of the recording magnetic pole 10. Further, the light irradiation element 20 is disposed at the end of the waveguide 11 on the medium facing surface 2 side. As the light irradiation element 20, any element can be used as long as it can perform heat-assisted magnetic recording by irradiating light to a desired minute region. For example, as the light irradiation element 20, a near-field light generating element that generates surface plasmon when light of a predetermined wavelength is irradiated and thereby generates near-field light can be used.

  The insulating layers 4, 7, 9, 13 and 15, the magnetic shield layer 5, the return magnetic pole 8, the recording magnetic pole 10, and the like constituting the heat-assisted magnetic head 50 are made of the same materials as those of the conventional heat-assisted magnetic head. Available. For example, the insulating layer can be formed of alumina or the like, and the magnetic shield layer 5 and each magnetic pole can be made of a magnetic material such as NiFe or CoFeNi. Further, the thickness, width, length, shape, and the like of each part constituting the heat-assisted magnetic head 50 can be the same as those of the conventional heat-assisted magnetic head. The heat-assisted magnetic head 50 can have any configuration as long as it can generate a desired recording magnetic field and the waveguide 11 and the recording magnetic pole 10 are not in direct contact with each other.

  Further, as the magnetic reproducing element 6, for example, a magnetoresistive effect (MR) element such as an in-plane conduction type (CIP) giant magnetoresistive effect (GMR) element or a tunnel magnetoresistive effect (TMR) element can be used. The material and configuration of the magnetic reproducing element 6 are not particularly limited as long as the material and configuration are recorded by heat-assisted magnetic recording and can reproduce high-density magnetic recording.

  Here, the structure of the 1st condensing part 30 and the 2nd condensing part 40 provided in the heat-assisted magnetic head 50 is demonstrated in detail. The first light collecting unit 30 and the second light collecting unit 40 condense light incident from the external light source via the light incident surface 51 toward the waveguide 11.

  In the example shown in FIG. 1, a plurality of high refractive index material layers extending in a direction perpendicular to the paper surface of FIG. 1 in the stacking direction of each part of the thermally-assisted magnetic head 50 (direction perpendicular to the side surface 3 of the slider substrate 1). 31 (material layer) is provided at a predetermined interval via an insulating layer (material layer) to constitute the first light collecting unit 30. Such a pattern of the stripe-like high refractive index material layer 31 can be easily formed by an existing manufacturing process. For example, first, after a layer made of a high refractive index material such as SiN having a high refractive index with respect to the insulating layer is formed on the insulating layer, the layer is patterned into a rod shape extending in a predetermined direction. A high refractive index material layer 31 is formed. Then, by repeating this process, a plurality of high refractive index material layers 31 are stacked in a direction perpendicular to the side surface 3 of the slider substrate 1 with an insulating layer interposed therebetween, whereby the first light collecting portion 30 is formed.

  The first condensing unit 30 having the above-described configuration functions as a diffraction grating type condensing unit (Fresnel lens-shaped condensing lens), and as shown by an arrow L1 in FIG. The emitted light (first light) is collected in a direction orthogonal to the side surface 3 of the slider substrate 1.

  The first condensing unit 30 is formed by appropriately adjusting the material, thickness, width, and the like of each high refractive index material layer 31, the distance between the high refractive index material layers 31, and the like. (Not shown) can be reduced in a predetermined ratio in a direction perpendicular to the side surface 3 of the slider substrate 1. As a result, in the 1st condensing part 30 of this embodiment, the incident light from a light source can be efficiently condensed on the light-incidence surface of the 2nd condensing part 40 which has thin thickness.

  In the present embodiment, an example is shown in which the end surface on the light incident surface 51 side of the high refractive index material layer 31 constituting the first light collecting unit 30 is formed so as to be exposed to the light incident surface 51. Is not limited to this. For example, if it is possible to introduce a sufficient amount of light from the light incident surface 51 side to the first light collecting unit 30, the end surface of the high refractive index material layer 31 on the light incident surface 51 side is referred to as the light incident surface 51. It may not be provided so as to be exposed. However, as in the present embodiment, the first light collecting unit 30 is configured such that the end surface on the light incident surface 51 side of the high refractive index material layer 31 is exposed to the light incident surface 51, thereby reducing the light utilization efficiency. Can be suppressed. That is, in the configuration of the first light collecting unit 30 of the present embodiment, incident light from the outside can be efficiently introduced into the waveguide 11.

  Further, in the present embodiment, the first light collecting unit 30 is arranged on the light incident surface 51 side, that is, in the preceding stage in the light propagation direction from the other units constituting the heat-assisted magnetic head 50. Such a configuration of the present embodiment also provides the following effects.

  In order to improve the light collection efficiency in the direction orthogonal to the side surface 3 of the slider substrate 1 in the first light collection unit 30, the thickness of the first light collection unit 30 having a laminated structure of a plurality of high refractive index material layers 31. It is preferable that the height is approximately the same as the spot size of incident light. However, in the manufacturing process of the heat-assisted magnetic head 50, the larger the thickness of the heat-assisted magnetic head 50, the more time-consuming and costly the process becomes. Therefore, as in the present embodiment, when the first light collecting unit 30 is disposed closer to the light incident surface 51 than the other components constituting the heat-assisted magnetic head 50, only the first light collecting unit 30 is present in that region. It is formed. That is, since it is not necessary to form any one of the other parts constituting the heat-assisted magnetic head 50 and the first light collecting unit 30 in the stacking direction, the thickness of the heat-assisted magnetic head 50 as a whole is increased. Can be suppressed. Therefore, as in the present embodiment, by arranging the first light collecting unit 30 closer to the light incident surface 51 than the other components constituting the heat-assisted magnetic head 50, the manufacturing time of the heat-assisted magnetic head 50 and An increase in cost can be suppressed. Note that, in the second modification (FIG. 7) of the first light collecting unit 30 to be described later, even when the first light collecting unit has a thick film structure, the other parts constituting the heat-assisted magnetic head 50 and the first Since it is not necessary to form the condensing part in the stacking direction, the same effect as that of the present embodiment can be obtained.

  Next, the structure of the 2nd light collection part 40 of this embodiment is demonstrated, referring FIG. FIG. 2 is a schematic top view of the second light collecting unit 40 and the waveguide 11 as seen from the direction (stacking direction) orthogonal to the side surface of the slider substrate 1. The 2nd condensing part 40 is a flat member with constant thickness, The surface has a plano-convex lens shape. In the present embodiment, the convex end surface (convex curved surface) of the second light collecting unit 40 is located on the light incident side, and the flat end surface on the opposite side is connected to the waveguide 11. Moreover, the 2nd light collection part 40 can be formed with high refractive index materials, such as SiN, for example. By making the 2nd condensing part 40 the above structure, the emitted light L1 from the 1st condensing part 30 which injects into the convex-shaped end surface of the 2nd condensing part 40 is a convex end surface, The light is condensed in the in-plane direction of the second light collecting unit 40 (the direction along the side surface 3 of the slider substrate 1) and in the direction orthogonal to the light propagation direction.

  In the present embodiment, the diameter of the light L1 from the first light collecting portion 30 is adjusted by appropriately adjusting the configuration of the second light collecting portion 40, for example, the shape, dimensions, curvature of the convex end surface, forming material, and the like. 1 can be reduced at a predetermined ratio in a direction along the side surface 3 of one and in a direction orthogonal to the light propagation direction. As a result, in the second light collecting unit 40 of the present embodiment, the light L1 from the first light collecting unit 30 can be efficiently collected on the waveguide 11.

  In addition, when the final condensing position of the light condensed by the 1st condensing part 30 and the 2nd condensing part 40 can be set to the vicinity of the light irradiation element 20, it does not provide the waveguide 11 The emitted light L2 from the second light collecting unit 40 may be directly introduced into the light irradiation element 20. However, depending on the size of the side surface 3 of the slider substrate 1, it may be difficult to collect light on the light irradiation element 20 using only the first light collecting unit 30 and the second light collecting unit 40. Further, when the condensed light crosses the recording magnetic pole 10, there is a possibility that the magnetic characteristic or the condensing characteristic of the heat-assisted magnetic head 50 is deteriorated. Therefore, when the size of the side surface 3 of the slider substrate 1 is relatively large, the waveguide 11 is provided between the second light collecting unit 40 and the light irradiation element 20 as in the present embodiment to avoid the inconvenience. It is preferable to do. However, in this case, the shape, arrangement position, and the like of the waveguide 11 are appropriately selected in consideration of the positional relationship between the recording magnetic pole 10 and the waveguide 11.

  As described above, each layer from the insulating layer 4 to the insulating layer 15 formed on the slider substrate 1 can be manufactured in a series of manufacturing steps by an existing film forming method and a patterning method such as photolithography. Therefore, in the present embodiment, the second light collecting unit 40 can be formed simultaneously with the step of forming the waveguide 11. On the other hand, the 1st condensing part 30 can be formed as follows, for example.

  When the high refractive index material layer 31 and the other layers of the first light collecting unit 30 are not arranged on the same plane, the film formation of the high refractive index material layer 31 is appropriately performed during the process of forming the other layers. The 1st condensing part 30 can be formed by putting the process of patterning. Alternatively, after forming each part other than the first light collecting part 30, the region on the light incident surface 51 side may be partially etched away to form the first light collecting part 30. In addition, the formation method of the 1st condensing part 30 is arbitrary, For example, it can change suitably according to the structure of each part other than the 1st condensing part 30, etc.

  Further, in the present embodiment, emitted light from a light source (not shown) is condensed by a condensing unit 72 such as a microlens formed on a substrate 71 separate from the slider substrate 1 to be thermally assisted. Although the structure which injects into the 1st condensing part 30 of the magnetic head 50 is shown, this invention is not limited to this. When a sufficient condensing function (condensing angle) is obtained by the first condensing unit 30 and the second condensing unit 40, the condensing unit 72 may not be provided. In the present embodiment, the heat-assisted magnetic head 50 may include a light source.

  However, when a sufficient condensing angle (condensing angle corresponding to the numerical aperture NA of the lens) cannot be obtained by the first condensing unit 30 and the second condensing unit 40, as in the present embodiment, external It is preferable to provide an optical system on the optical path to obtain a desired condensing angle. In particular, when the desired condensing angle cannot be obtained with only the first condensing unit 30 and the second condensing unit 40 due to restrictions on the type of light source, the spread angle of the emitted light, the manufacturing method, etc. As in the embodiment, it is preferable to secure desired light collecting characteristics in combination with an external optical system (light collecting element).

(2) Description of light collecting operation by first and second light collecting units The light collecting operation by the first light collecting unit 30 and the second light collecting unit 40 described above will be described with reference to FIG. FIG. 3 is a schematic perspective view of the heat-assisted magnetic head 50. In FIG. 3, portions corresponding to those in FIG. 1 are denoted by the same reference numerals, and description of the corresponding portions is omitted. Moreover, in FIG. 3, only the 1st condensing part 30, the 2nd condensing part 40, and the light irradiation element 20 are shown in order to simplify description, and another structure part is abbreviate | omitted. Further, in FIG. 3, the direction perpendicular to the side surface 3 of the slider substrate 1 (the stacking direction of the first light collecting portions 30) is the x-axis direction, the in-plane direction of the side surface 3 of the slider substrate 1, and the incident light Li A direction orthogonal to the incident direction (track width direction of the recording medium 240) is taken as a y-axis direction. In FIG. 3, the direction orthogonal to the x-axis and y-axis directions, that is, the propagation direction of the incident light Li is defined as the z-axis direction.

  In the present embodiment, as shown in FIG. 3, the first light collecting unit 30 and the second light collecting unit 40 are formed on the side surface 3 of the slider substrate 1 in a stacked manner. For example, the light Li of the light spot B emitted from an external light source (not shown) such as an LD is incident from the light incident surface 51 side opposite to the medium facing surface 2 side of the heat-assisted magnetic head 50. . As described above, the first light collecting unit 30 is preferably provided on the light incident surface 51 side and configured as a diffraction grating type (Fresnel lens type) lens element. By adopting such a configuration, it is not necessary to form the high refractive index material layer 31 so as to extend to the light incident surface of the second light collecting section 40, and the width and thickness of the high refractive index material layer 31 are not required. And the arrangement position can be accurately and easily controlled by an existing manufacturing process.

  In the present embodiment, as shown in FIG. 3, the thickness of the first light collecting unit 30 made of a plurality of high refractive index material layers 31 in the x-axis direction is set to the entire diameter of the light spot B of the incident light Li. It is preferable to set the thickness so that the first light collecting unit 30 can receive light. That is, it is preferable that the width of the pattern of the striped high refractive index material layer 31 in the x-axis direction and the y-direction is larger than the diameter of the light spot B of the incident light Li. With this configuration, the incident light Li can be efficiently condensed in the x-axis direction as indicated by the emitted light L1 (first light) of the first light collecting unit 30 in FIG.

  At this time, the light collecting action by the first light collecting unit 30 does not work in the y-axis direction, and the spot shape of the emitted light L1 becomes an elliptical shape elongated in the y-axis direction. That is, the diameter of the light spot B of the incident light Li is a direction perpendicular to the side surface 3 of the slider substrate 1 in the first light collecting unit 30 (thickness direction of the first light collecting unit 30: x-axis direction in FIG. 3). Reduced to The reduction ratio of the spot diameter is determined by the thickness (width in the x-axis direction), the width (width in the z-axis direction), the length in the y-axis direction, the distance between the high-refractive index material layers 31, and the surroundings. It can be appropriately adjusted depending on the difference in refractive index from the material. In the present embodiment, an example in which four high refractive index material layers 31 are provided is shown, but the present invention is not limited to this. The number of layers of the high-refractive index material layer 31 can be appropriately selected depending on, for example, a necessary condensing angle, a spot diameter of light from a light source, and the like.

  On the other hand, the 2nd condensing part 40 is arrange | positioned so that the convex incident end surface may be located in the condensing position vicinity of the emitted light L1 from the 1st condensing part 30. FIG. The second light collecting unit 40 is formed of a high refractive index material layer having a predetermined thickness (width in the x-axis direction), and the thickness is the total thickness of the first light collecting unit 30 (x-axis direction). Thinner). In addition, the second light collector 40 is arranged so that the center of the convex incident end face of the second light collector 40 and the center of the first light collector 30 are coaxial in the z-axis direction. The In this way, by arranging the second light collector 40, the formation pattern of the high refractive index material layer 31 of the first light collector 30 as viewed from the center of the convex incident end face of the second light collector 40. Is symmetric in the x-axis direction. As a result, the emitted light L1 from the first light collecting unit 30 can be efficiently introduced into the convex incident end face of the second light collecting unit 40. In addition, when the light introduced into the 1st condensing part 30 has a light intensity distribution which is not symmetrical, the arrangement configuration of each high refractive index material layer 31 of the 1st condensing part 30 is matched with it. You may make it asymmetric with respect to the center of the optical part 30. FIG.

  Moreover, by making the thickness of the second light collecting portion 40 constant, it can be formed by a single film formation and patterning. Then, by configuring the end surface (side surface) on the light incident side of the second light collecting unit 40 with a convex lens-like curved surface, the light L1 incident on the second light collecting unit 40 from the first light collecting unit 30 is 2 Condensed at the convex lens-shaped end surface of the condensing unit 40. At this time, the light incident on the convex lens-shaped end surface of the second light collecting section 40 is orthogonal to the light propagation direction in the in-plane direction of the side surface 3 of the slider substrate 1 as indicated by light L2 in FIG. The light is condensed in the direction, that is, the y-axis direction (track width direction of the recording medium 240) in FIG. That is, when the light L1 having a spot elongated in the y-axis direction in FIG. 3 emitted from the first light collecting unit 30 is incident on the second light collecting unit 40, the spot diameter in the longitudinal direction is the second. The light is reduced by the light collecting unit 40. As a result, light L2 (second light) having a narrow spot diameter that is almost circular is obtained at the exit of the second light collecting unit 40. The reduction ratio of the spot diameter of the incident light in the second light collecting unit 40 is the length, width (length in the y axis direction), convex length of the light propagation direction (z axis direction) of the second light collecting unit 40. Can be accurately adjusted according to the curvature, material, and the like of the end face. Further, the shape parameters of the second light collecting unit 40 can be easily and accurately adjusted by an existing manufacturing process.

  As described above, the light is condensed two-dimensionally in the x-axis direction (stacking direction) by the first light collecting unit 30, and in the y-axis direction (direction orthogonal to the stacking direction) by the second light collecting unit 40. The two-dimensionally condensed light is introduced into the waveguide 11 arranged in the vicinity of the condensing location of the second condensing unit 40. Then, the light introduced into the waveguide 11 propagates through the waveguide 11 and irradiates the light irradiation element 20 disposed at the exit of the waveguide 11. When a near-field light generating element using a surface plasmon resonance phenomenon is used for the light irradiation element 20, when the light irradiation element 20 is irradiated with the propagation light of the waveguide 11, the surface plasmon is excited in the light irradiation element 20. , Near-field light having a predetermined intensity and spot diameter is generated. The near-field light generated by the light irradiation element 20 is emitted toward a predetermined minimum region of the recording medium 240. In addition, simultaneously with the irradiation of the near-field light onto the recording medium 240, a magnetic field having a predetermined intensity is applied to the light irradiation area by the recording magnetic pole 10 (not shown in FIG. 3), thereby thermally assisted magnetic recording on the recording medium 240. It can be performed. In the present invention, the light irradiation element 20 is not limited to the near-field light generating element. As long as it is an element that can irradiate minute light locally to a desired minute region capable of high-density recording, a light irradiation element of any configuration can be used, and the same effect can be obtained. .

  By the way, as described above, the waveguide 11 is preferably provided as appropriate according to the size of the slider substrate 1, for example. However, at this time, it is preferable that the waveguide 11 is constituted by a single mode waveguide, not a multimode waveguide in which inter-mode interference occurs. When the waveguide 11 is configured by a single mode waveguide, the incident light can be propagated in a single mode regardless of the length (extending length) of the light propagation direction of the waveguide 11. As a result, variations in light intensity caused by inter-mode interference can be suppressed or made almost zero. As described above, the light intensity distribution due to the inter-mode interference usually appears periodically in the light propagation direction. Therefore, when the light propagation length (extension length of the waveguide 11) is relatively short, the light intensity It is possible to accurately predict the position where becomes large. However, for example, when light is propagated over a relatively long distance of about several hundred μm or more, the mode of inter-mode interference changes due to, for example, the formation error of the length of the waveguide 11 or internal crystal defects, and the light It is difficult to accurately control the positions that strengthen each other. Therefore, when connecting the 2nd condensing part 40 and the light irradiation element 20 with the waveguide 11, it is preferable to comprise the waveguide 11 with a single mode waveguide.

  In order to make the waveguide 11 a single mode waveguide, the width and thickness are constant with respect to the extending direction, that is, the cross-sectional shape of the waveguide 11 is constant, and the dimensions thereof are set to, for example, the wavelength of the propagating light. Accordingly, the waveguide mode is appropriately adjusted so as to be single. For example, when light having a wavelength of 850 nm is introduced into the waveguide 11, the width and thickness of the waveguide 11 need to be about 300 nm or less. That is, in this case, the LD used for the light source usually has a spot diameter on the order of several μm, and since it is a divergent light, the light spot size increases as it propagates. Needs to be reduced by about one digit or more of the diameter of the light emitted from the light source. In this case, when light from the light source is directly incident on the waveguide 11, the light that is not introduced into the core of the waveguide becomes radiated light as it is. Therefore, the light utilization efficiency (coupling efficiency) in the waveguide 11 is deteriorated.

  On the other hand, in the heat-assisted magnetic head 50 of this embodiment, as described above, the first light collecting unit 30 and the second light collecting unit 40 cause the light from the light source to be emitted in two stages in the x-axis direction and the y-axis direction. Then, the condensed light is introduced into the waveguide 11. At this time, for example, in the first light collecting unit 30 shown in FIG. 3, the spot diameter of the incident light Li in the x-axis direction (stacking direction) is first reduced to about 1/10. Subsequently, the second condensing unit 40 reduces the spot diameter of the emitted light L1 from the first condensing unit 30 in the y-axis direction (track width direction of the recording medium 240) to about 1/10. As a result, the spot diameter of the light L2 introduced into the waveguide 11 is about one digit smaller than that of the incident light Li. Therefore, in the heat-assisted magnetic head 50 of the present embodiment, it is possible to easily suppress the deterioration of the light utilization efficiency (coupling efficiency) in the waveguide 11 described above, and efficiently emit light from the light source to the light irradiation element. 20 can be led. As a result, light having sufficient intensity can be stably introduced into the light irradiation element 20.

  Even when the diameter of the light from the light source is larger than the dimension of the waveguide 11 (about several tens of times), by appropriately setting the configuration (for example, size, shape, etc.) of each condensing unit, The light Li can be easily condensed (reduced) to a desired spot diameter, and the same effect can be obtained.

(3) Condensing characteristic of first condensing unit In the present embodiment, the condensing characteristic of the above-described Fresnel lens-shaped (diffraction grating type) first condensing unit 30 was examined by simulation analysis. FIG. 4 shows a model outline of the first light collecting unit 30 used in the simulation analysis.

  In the model of the first light collecting unit 30 shown in FIG. 4, four high-refractive index material layers 31 a, 31 b, 31 c, and 31 d are provided via the insulating layer 15 on the light incident side of the light spot B. Arranged in stripes. In such a model, in the present embodiment, a light intensity distribution (electric field intensity distribution) at a position entering the first light collecting unit 30 side by 2 μm from the light incident surface of the light spot B is calculated, and the first collection is performed. The condensing characteristic of the optical part 30 was investigated by simulation analysis.

The parameters used in this simulation analysis are as follows.
T1: 2200 [nm]
T2: 3220 [nm]
T3: 4060 [nm]
T4: 4820 [nm]
L: 850 [nm]
Spot diameter of incident light Φ (1 / e ² ): 3000 [nm]
Light source wavelength λ: 850 [nm]

The parameter “T1” is the distance between the side surfaces facing each other between the high refractive index material layer 31b and the high refractive index material layer 31c, and the parameter “T2” is the distance between the side surfaces not facing each other. The parameter “T3” is the distance between the side surfaces facing each other between the high refractive index material layer 31a and the high refractive index material layer 31d, and the parameter “T4” is the distance between the side surfaces not facing each other. Further, the parameter “L” is the length of the light propagation direction (z-axis direction) of each of the high refractive index material layers 31a to 31d. The spot diameter Φ of incident light is a diameter at which the intensity is 1 / e ^{2 of the} maximum intensity.

FIG. 5 shows the simulation results. In FIG. 5, the vertical axis indicates the electric field intensity | E | 2, and the horizontal axis indicates the position in the x-axis direction from the center of the incident light. Also, the characteristic a in FIG. 5 is the electric field intensity distribution of the incident light before being incident on the first light collecting unit 30, and the characteristic b enters the first light collecting unit 30 side by 2 μm from the incident surface. It is an electric field strength distribution of light at a position.

  As apparent from the result of FIG. 5, the spot diameter of the incident light before being incident on the first condensing unit 30 is about 3000 nm, whereas the incident light enters the first condensing unit 30 side by 2 μm. It can be seen that the spot diameter in the x-axis direction (stacking direction) is as small as about 940 nm at this position. In addition, it can be seen that the peak value of the light intensity also increases about twice as much as the incident light ratio.

  From the above results, it is possible to condense incident light two-dimensionally by configuring the first condensing unit 30 with a Fresnel lens-like (diffraction grating type) element as in this embodiment. It can be seen that the peak value of the light intensity can also be increased. From this, it can be seen that the configuration of the present embodiment can condense incident light and efficiently guide it to the waveguide 11.

<2. Modified Example of First Embodiment (Heat Assisted Magnetic Head)>
Next, various modifications of the first and second light converging units in the heat-assisted magnetic head 50 of the first embodiment will be described.

[Modification 1]
In FIG. 6, the schematic sectional drawing of the 1st and 2nd condensing part of the modification 1 is shown. The first light collector 32 of the first modification includes two refractive index material layers 33a and 33e having a refractive index n1, two refractive index material layers 33b and 33d having a refractive index n2, and a refractive index material layer having a refractive index n3. 33c. The relationship between the refractive index of each refractive index material layer and the refractive index n0 of the surrounding insulating layers 16 and 17 is as follows:
n0 <n1 <n2 <n3
It is. Hereinafter, the refractive index material layers (material layers) having the refractive indexes n1, n2, and n3 are referred to as a low refractive index material layer, a middle refractive index material layer, and a high refractive index material layer, respectively.

  For example, the low refractive index material layer is made of quartz (refractive index: 1.45), the medium refractive index material layer is made of alumina (refractive index: 1.65), and the high refractive index material layer is made of tantalum oxide. When formed with (refractive index: 2.15), the above-described refractive index relationship can be satisfied.

  The first condensing part 32 of Modification 1 includes, from the lower layer side, a low refractive index material layer 33a, a medium refractive index material layer 33b, a high refractive index material layer 33c, a medium refractive index material layer 33d, and a low refractive index material. The layer 33e is configured by being laminated adjacently in this order. That is, the first light collecting portion 32 of this example is configured such that the refractive index decreases with increasing distance from the vertical direction (thickness direction) about the high refractive index material layer 33c.

  Further, in this example, the second light collecting unit 40 is formed of a refractive index material layer having a refractive index n3, and is integrally formed on the same surface as the high refractive index material layer 33c of the first light collecting unit 32.

  Thus, when the refractive index is increased at the center in the stacking direction and the first light collecting section 32 is configured by stacking layers whose refractive index decreases as the distance from the center increases, as light propagates through the first light collecting section 32. In the high refractive index material layer 33c having the highest refractive index, the light intensity can be relatively increased. Therefore, the first light collecting unit 32 can substantially collect the light spot in the stacking direction. In this configuration, for example, the low-refractive index material layer 33a, the medium-refractive index material layer 33b, and the like can be continuously formed by one patterning, and therefore, compared to the configuration of the first light collecting unit 30 shown in FIG. This has the advantage that the number of processes can be reduced.

[Modification 2]
In FIG. 7, the schematic sectional drawing of the 1st and 2nd condensing part of the modification 2 is shown. In this example, the first light collecting unit 34 is configured by a single refractive index material layer 35. In this example, when the refractive indexes of the upper and lower insulating layers 18 and 19 of the first light collecting portion 34 are n0, and the refractive indexes of the refractive index material layer 35 and the second light collecting portion 40 are n1,
n0 <n1
The material of each layer is selected so that

  Further, in the first light collector 34 of this example, the refractive index material layer 35 is formed with a uniform thickness from the incident side of the first light collector 34 to the second light collector 40. Moreover, the thickness is made thicker than the thickness of the second light collecting unit 40. That is, in this example, the first condensing part 32 configured by stacking a plurality of refractive index material layers having different refractive indexes described in Modification 1 (FIG. 6) is replaced with one refractive index material layer 35. It becomes the composition. Other configurations are the same as those of the first modification.

  In the first light collecting section 34 having such a structure, a place where the light intensity is increased is formed at a specific place due to multimode interference. What is necessary is just to form the incident part of the 2nd condensing part 40 in the part. Further, in the first light collecting section 34 of this example, incident light (diverging light) is reflected at the interface between the refractive index material layer 35 and the upper and lower insulating layers 18 and 19. Therefore, also in this example, it is possible to collect the light spot in the thickness direction of the first light collecting unit 34.

[Modification 3]
In the above-described first embodiment (FIG. 2), the surface shape of the second light collecting unit 40 (the shape of the surface parallel to the side surface 3 of the slider substrate 1) is a plano-convex lens shape. It is not limited to, It can comprise in various shapes. Modification 3 shows an example thereof.

  In FIG. 8, the schematic structure of the 2nd condensing part in the modification 3 is shown. In this example, the surface shape of the second light collecting portion 42 is substantially triangular, the apex angle portion is connected to the waveguide 11, and the end surface on the base side is on the incident side (first light collecting portion side) of the light L1. It is arranged to be located. That is, the second light collecting portion 42 in this example has a shape that gradually decreases in width from the incident side of the light L1. If the 2nd condensing part 42 is made into such a structure, the light L1 (light condensed in the thickness direction of the 2nd condensing part 42) incident on the end face of the bottom side of the 2nd condensing part 42 will be As shown by an arrow L2 in FIG. 8, the light is collected in a direction orthogonal to the light propagation direction in the plane of the second light collecting unit 42. As a result, the light condensed at the target spot diameter reaches the entrance of the waveguide 11. Therefore, also in this example, it is possible to satisfactorily introduce light into the waveguide 11 without causing a decrease in light utilization efficiency.

  When a near-field light generating element that generates surface plasmons and emits near-field light is used as the light irradiation element 20, it is necessary to irradiate the light irradiation element 20 while maintaining the polarization direction of light in a specific direction. There is. Therefore, in the second light collecting unit including the example shown in FIG. 2 (first embodiment) and FIG. 8 (modified example 3), the inclination angle of the end surface (side surface) portion inclined with respect to the light propagation direction, It is preferable to select the size appropriately so that the phase of the light at the light exit of the second light collecting unit is aligned.

[Modification 4]
In the first embodiment (FIG. 1), in order to obtain a desired light collection angle, a substrate 71 is provided between the first light collection unit 30 and the light source in addition to the first and second light collection units. Although the example which provides the convex lens-shaped condensing part 72 in the light source side of the board | substrate 71 was demonstrated, this invention is not limited to this. In Modification 4, another configuration example of a condensing optical system provided outside the thermally-assisted magnetic head will be described.

  FIG. 9 shows a schematic cross-sectional configuration in the vicinity of the thermally-assisted magnetic head of Modification 4. In this example, a substrate 81 is attached to a surface opposite to the medium facing surface 2 of the slider substrate 1 via a connecting portion 61 made of, for example, an adhesive, and a light source 83 such as a VCSEL is mounted on the substrate 81. Provided. The light source 83 is disposed at a position facing the first light collecting unit 30.

  In this example, a condensing optical system 82 such as a microlens is formed on the surface of the substrate 81 facing the first condensing unit 30. Also in this example, as in the first embodiment, by separating the condensing function between the inside and outside of the thermally-assisted magnetic head, the design conditions and design accuracy are eased compared to the case where the condensing function is realized by only one side. Has the advantage of being

  In the example shown in the first embodiment (FIG. 1) and the modification 4 (FIG. 9), the lens is used as the light collecting unit provided outside the heat-assisted magnetic head. However, the present invention is not limited to this. . As the external optical system, for example, a waveguide having a similar light collecting function may be used, or a waveguide and an optical system including the lens described above may be combined.

[Modification 5]
In the first embodiment and the various modifications, the example in which the light incident on the heat-assisted magnetic head from the light source is one is described, but the present invention is not limited to this, and in order to increase the light intensity, A plurality of lights may be incident on the thermally assisted magnetic head. A plurality of lights may be emitted from a plurality of light sources, respectively, or a plurality of light emitting units may be arranged in an array in one light source to generate a plurality of lights. In Modified Example 5, a configuration example of a thermally assisted magnetic head using a plurality of lights generated by the latter method will be described.

FIG. 10 shows a schematic configuration of the heat-assisted magnetic head of Modification 5 . In FIG. 10, parts corresponding to those in the configuration of the first embodiment (FIGS. 1 and 3) are denoted by the same reference numerals, and redundant description thereof is omitted. In order to simplify the description, FIG. 10 shows only the part necessary for generating the recording light, and omits the part necessary for generating the recording magnetic field.

  In the heat-assisted magnetic head 50 of this example, the first condensing unit has the same configuration as that of the first embodiment. On the other hand, as shown in FIG. 11, the second condensing unit 140 has a fan-shaped surface shape (a shape parallel to the side surface 3 of the slider substrate 1), and an end surface on the long side of the arc shape is the first. It arrange | positions so that 1 condensing part may be opposed. Note that the width of the end surface on the long side of the arc of the second light collecting unit 140 is set to such a width that all of the plurality of lights are introduced. Also in this example, by making the thickness (width in the direction orthogonal to the side surface 3 of the slider substrate 1) constant for the second light collecting portion 140, it can be easily manufactured without increasing the number of steps in the existing process. can do.

  In this example, a light source (not shown) in which a plurality of surface emitting lasers such as VCSELs that are easily arrayed is arranged, and light spots B1, B2, B3,. The light is collected in two stages by the first light collecting unit 130 and the second light collecting unit 140. In the example shown in FIG. 10, an example in which a plurality of surface emitting lasers (light emitting units) are arranged in the y-axis direction along the track width direction of the recording medium 240 is shown.

  The light condensing operation in the configuration of this example is as follows. First, a plurality of lights respectively emitted from a plurality of surface emitting lasers are incident on the first light collecting unit 130. Each high refractive index material layer 131 constituting the first light collecting unit 130 is formed such that its longitudinal direction extends in the y-axis direction over a region irradiated with a plurality of lights. Therefore, the plurality of lights incident on the first light collecting unit 130 can be condensed in the stacking direction of the high refractive index material layer 131 without impairing the light utilization efficiency, as in the first embodiment. it can.

  Then, the light condensed in the stacking direction of the high refractive index material layer 131 by the first light collecting unit 130 is incident on the end surface of the second light collecting unit 140 on the long side of the arc. As shown in FIGS. 10 and 11, the second condensing unit 140 becomes narrower in the light propagation region from the light incident surface toward the waveguide 11. Therefore, the light incident on the second light collector 140 is condensed toward the entrance of the waveguide 11 in the plane of the second light collector 140, as indicated by an arrow L2 in FIG. be able to. That is, the light incident on the second light collecting unit 140 is collected in a direction orthogonal to the light propagation direction in the plane of the second light collecting unit 140.

  As described above, also in this example, a plurality of light incident on the heat-assisted magnetic head 50 can be obtained by performing a one-dimensional condensing operation in two stages as in the first embodiment. Light having a spot diameter can be efficiently introduced into the waveguide. Therefore, also in this example, a larger optical power can be obtained, and it becomes possible to irradiate a narrow area with higher intensity light.

  10 and 11 show three examples of light incident on the thermally-assisted magnetic head 50. However, the present invention is not limited to this, and the number of incident light is two or four. It may be more than one.

  When a near-field light generating element that generates surface plasmons and emits near-field light is used as the light irradiation element 20, it is necessary to irradiate the light irradiation element 20 while maintaining the polarization direction of light in a specific direction. There is. Therefore, also in the second light collecting portion 140 of this example, the inclination angle and size of the end face (side surface) portion that is inclined with respect to the light propagation direction are appropriately selected, and the light collecting port at the light collecting port of the second light collecting portion is selected. It is preferable to align the phases of the light.

  Further, the near-field light generating element is usually composed of a metal structure, and the generation form of surface plasmons varies depending on the structure (for example, shape, extending direction, etc.). Therefore, when such a near-field light generating element is used as the light irradiating element 20, thermal assist is performed so that high-intensity surface plasmon is generated at a predetermined position according to the structure of the near-field light generating element. It is preferable to adjust the polarization direction of the light incident on the magnetic head 50.

<3. Second Embodiment>
FIG. 12 shows a schematic configuration example of a recording / reproducing system when a recording medium (magnetic recording medium) is attached to the recording / reproducing apparatus according to the second embodiment of the present invention. In this embodiment, a recording / reproducing apparatus that emits near-field light from a heat-assisted magnetic head to an information recording medium and records and / or reproduces information will be described.

  The recording / reproducing apparatus 210 mainly includes a flying slider 211, a suspension 212 that supports the flying slider 211, a head actuator 213 (driving unit) that drives the flying slider 211, and a spindle 214. The recording medium 240 is fixed to a mounting table or the like (not shown) on the rotation shaft 215 of the spindle 214 and is driven to rotate.

  In the present embodiment, the recording medium 240 is a disk-shaped medium and has the same configuration as the recording medium described in the first embodiment. That is, the recording medium 240 includes a substrate (not shown) and a magnetic recording layer formed on the substrate. Then, the recording medium 240 is mounted on the spindle 214 so that the magnetic recording layer faces the lower surface of the flying slider 211. In addition, a lubricant and a protective film are appropriately formed on the surface of the recording medium 240 to have a thin thickness in order to prevent damage due to contact between the flying slider 211 and the recording medium 240 during operation of the recording / reproducing apparatus 210.

  FIG. 13 shows an enlarged side view of the vicinity of the flying slider 211 of the recording / reproducing apparatus 210 of the present embodiment. The flying slider 211 includes a slider body 216 and a heat-assisted magnetic head 220 mounted at the tip of the slider body 216.

  The slider body 216 is disposed in close proximity to the recording medium 240 when the recording / reproducing apparatus 210 operates. At this time, the heat-assisted magnetic head 220 is also disposed so as to face the recording medium 240.

  In the present embodiment, as the heat-assisted magnetic head 220, for example, a heat-assisted magnetic head having the same configuration as that of the above-described first embodiment or the heat-assisted magnetic head 50 of various modifications is used. Therefore, according to the present embodiment, a decrease in light utilization efficiency is further suppressed, heat-assisted recording using minute light with sufficient light intensity is possible, and high-density magnetic recording can be performed satisfactorily.

  Further, as described above, in the present embodiment, since the heat-assisted magnetic head according to the first embodiment is used, output light from a light source such as an LD, for example, is output in a one-dimensional direction in the heat-assisted magnetic head. The light can be condensed by performing the light condensing operation in two stages. Specifically, in the first stage of the light condensing operation, first, a laminated structure of a plurality of refractive index material layers (near the light incident surface 51 opposite to the medium facing surface 2 of the thermally-assisted magnetic head) ( The incident light is condensed in the stacking direction of the refractive index material layers by the first condensing unit 30 including FIGS. Next, in the second stage of the light condensing operation, light is condensed in a direction orthogonal to the light propagation direction within the plane of the second light condensing portion made of a single refractive index material layer.

  In the case of adopting such a condensing method in which the one-dimensional condensing operation is performed in two stages, a laminating process in the same direction as the laminating direction of each part in the manufacturing process when manufacturing the heat-assisted magnetic head on the slider substrate is performed. There is an advantage that the above-described light collecting function can be realized. That is, in this embodiment, since the heat-assisted magnetic head according to the first embodiment is used, a structure having a light collecting function easily by a stacking process in the same direction as the stacking direction of each part in the manufacturing process of the heat-assisted magnetic head. A body (first and second light condensing portions) can be produced.

  1. 1. slider substrate, 2. medium facing surface; Side, 4, 7, 9, 13, 15-19. 4. insulating layer; 5. magnetic shield layer; 7. magnetic reproducing element; Return pole, 10. 10. magnetic pole for recording; Optical waveguide, 14. Coil, 20. Light irradiation element, 30, 32, 34. First light collecting unit, 31. High refractive index material layer, 40, 42. Second light collecting section, 50. 51 heat-assisted magnetic head; Light incident surface, 61. Connection part, 71, 81. Substrate 72, 82. Condensing part, 210. Recording / reproducing apparatus, 211. Flying slider, 212. Suspension, 213. Head actuator, 220. Heat-assisted magnetic head, 240. recoding media

Claims (7)

A condensing part for condensing light from a light source incident from the side opposite to the medium facing surface side of the slider substrate is formed on the surface of the slider substrate opposite to the medium facing surface side, An optical substrate connected to the medium facing surface side;
A plurality of material layers having different refractive indexes are laminated in a direction perpendicular to the side surface of the slider substrate on the side surface orthogonal to the medium facing surface of the slider substrate, and the light from the optical substrate is transmitted. A first condensing unit that condenses light in a direction perpendicular to the side surface of the slider substrate and emits the condensed first light;
On the side surface of the slider substrate and on the emission side of the first light of the first light collecting portion , the thickness of the first light collecting portion is smaller than the thickness in the direction perpendicular to the side surface of the slider substrate. Provided in a direction orthogonal to the side surface of the slider substrate, the thickness in the direction orthogonal to the side surface of the slider substrate is constant, the incident surface of the first light is a convex curved surface, The first light emitted from the second light is condensed in a direction parallel to the side surface of the slider substrate and perpendicular to the propagation direction of the first light, and the second light that is collected is emitted. A light collecting part;
Recording that is provided on the side surface of the slider substrate and on the second light output side of the second light collecting unit, and irradiates the recording medium with the second light emitted from the second light collecting unit. A light irradiation element that generates light and emits the recording light; and
A waveguide that is provided on the side surface of the slider substrate between the second light converging unit and the light irradiation element, and guides the second light emitted from the second light converging unit to the light irradiation element. When,
Magnetic recording is provided on the side surface of the slider substrate via an insulating layer , generates a recording magnetic field, and applies the generated recording magnetic field to an area irradiated with the recording light of the recording medium A heat-assisted magnetic head comprising the element. Said waveguide is thermally assisted magnetic head according to claim 1, which is a single mode waveguide. The thermally assisted magnetic head according to claim 1 or 2 the shape and dimensions of the cross section of the waveguide is constant perpendicular to the extending direction of the waveguide. The thermally-assisted magnetic head according to claim 1, wherein the light irradiation element is a near-field light generating element that generates near-field light using surface plasmons. The heat-assisted magnetic head according to any one of claims 1 to 4, further comprising the light source. A condensing part for condensing light from a light source incident from the side opposite to the medium facing surface side of the slider substrate is formed on the surface of the slider substrate opposite to the medium facing surface side, A diffraction grating in which an optical substrate connected to the medium facing surface side and a plurality of material layers having different refractive indexes are laminated on a side surface perpendicular to the medium facing surface of the slider substrate in a direction perpendicular to the side surface of the slider substrate. A first condensing part that condenses light from the optical substrate in a direction perpendicular to the side surface of the slider substrate, and emits the condensed first light, and the slider substrate On the side surface of the slider substrate with a thickness smaller than the thickness of the first light collecting portion in the direction perpendicular to the side surface of the slider substrate on the side surface and on the first light emitting side of the first light collecting portion. provided in a direction perpendicular side surfaces of the slider substrate The thickness of the orthogonal directions is constant, the incident surface of the first light is a convex curved surface, and a said emitted from the first condensing unit first light parallel to the side surface of the slider substrate A second condensing unit that condenses light in a direction perpendicular to the propagation direction of the first light and emits the condensed second light; and the second condensing unit on the side surface of the slider substrate. A light irradiation element that is provided on the emission side of the second light of the unit, generates recording light to be emitted to the recording medium by the second light emitted from the second light collecting unit, and emits the recording light A waveguide that is provided between the second light collecting unit and the light irradiation element and guides the second light emitted from the second light collecting unit to the light irradiation element, and the slider substrate It provided so as not to contact with the waveguide on the side, to generate a recording magnetic field, prior to the recording magnetic field thus generated in the recording medium A thermally assisted magnetic head and a magnetic recording element to be applied to the area where the recording light is irradiated,
A recording / reproducing apparatus comprising: a drive unit that drives the thermally-assisted magnetic head. The recording / reproducing apparatus according to claim 6 , wherein the heat-assisted magnetic head further includes a magnetic reproducing element for reproducing information recorded on the recording medium.

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