WO2012128198A1 - Tête magnétique à assistance lumineuse et dispositif d'enregistrement magnétique à assistance lumineuse - Google Patents

Tête magnétique à assistance lumineuse et dispositif d'enregistrement magnétique à assistance lumineuse Download PDF

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Publication number
WO2012128198A1
WO2012128198A1 PCT/JP2012/056821 JP2012056821W WO2012128198A1 WO 2012128198 A1 WO2012128198 A1 WO 2012128198A1 JP 2012056821 W JP2012056821 W JP 2012056821W WO 2012128198 A1 WO2012128198 A1 WO 2012128198A1
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WO
WIPO (PCT)
Prior art keywords
light
assisted magnetic
magnetic head
mirror
optical element
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Application number
PCT/JP2012/056821
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English (en)
Japanese (ja)
Inventor
黒釜龍司
田中秀樹
Original Assignee
コニカミノルタアドバンストレイヤー株式会社
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Publication of WO2012128198A1 publication Critical patent/WO2012128198A1/fr

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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/127—Structure or manufacture of heads, e.g. inductive
    • G11B5/31—Structure or manufacture of heads, e.g. inductive using thin films
    • G11B5/3109—Details
    • G11B5/313—Disposition of layers
    • G11B5/3133—Disposition of layers including layers not usually being a part of the electromagnetic transducer structure and providing additional features, e.g. for improving heat radiation, reduction of power dissipation, adaptations for measurement or indication of gap depth or other properties of the structure
    • G11B5/314—Disposition of layers including layers not usually being a part of the electromagnetic transducer structure and providing additional features, e.g. for improving heat radiation, reduction of power dissipation, adaptations for measurement or indication of gap depth or other properties of the structure where the layers are extra layers normally not provided in the transducing structure, e.g. optical layers
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
    • G11B5/58—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B5/60—Fluid-dynamic spacing of heads from record-carriers
    • G11B5/6005—Specially adapted for spacing from a rotating disc using a fluid cushion
    • G11B5/6088—Optical waveguide in or on flying head
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B2005/0002—Special dispositions or recording techniques
    • G11B2005/0005—Arrangements, methods or circuits
    • G11B2005/0021—Thermally assisted recording using an auxiliary energy source for heating the recording layer locally to assist the magnetization reversal

Definitions

  • the present invention relates to an optically assisted magnetic recording head and an optically assisted magnetic recording apparatus, and more specifically, enables extremely high density magnetic recording by performing magnetic recording by heating and heating a magnetic recording medium by light irradiation.
  • the present invention relates to an optically assisted magnetic recording head and an optically assisted magnetic recording apparatus.
  • a method for generating near-field light a method in which light from a light source is guided to a plasmon probe fabricated in a minute shape and the plasmon probe generates a near-field is the mainstream.
  • the means using the optical fiber is to irradiate the plasmon probe with the light emitted from the light emitting end of the optical fiber combined with the light from the light source through the prism having a reflection function.
  • the means using the lens optical system is to collimate the light from the light source with the lens and to irradiate the plasmon probe by using a transparent condensing medium which is a reflecting means having a convergence function.
  • the light reflected by the prism is irradiated to the plasmon probe, so that the plasmon probe is irradiated when the prism is slightly deviated from the ideal position. There is a risk that the intensity of the emitted light will fall.
  • the spot diameter of the collected light is as small as several ⁇ m, so even if the angle of the transparent condensing medium is slight, If the position is shifted, the position of the spot is shifted from the position of the plasmon probe, and the intensity of the near-field light is reduced.
  • the present invention greatly reduces the accuracy of the process of guiding the light from the light source to the plasmon probe, improves the mass productivity by shortening the manufacturing time and improving the yield, and is resistant to environmental changes and changes over time.
  • An object is to provide an assist magnetic head and an optically assisted magnetic recording apparatus.
  • An optically assisted magnetic head comprising a light source and an optical waveguide in which light from the light source is coupled and a plasmon probe is disposed at an emission end, In the optical path from the light source to the optical waveguide, an optical element that includes a plurality of mirror surfaces and bends the direction of light emitted from the light source by a predetermined angle by reflection on the plurality of mirror surfaces, An optically assisted magnetic head characterized in that light emitted from the optical element is directly coupled to the optical waveguide.
  • the optical element includes a first mirror surface and a second mirror surface, 3.
  • the optically assisted magnetic head as described in 1 or 2 above, wherein light from the light source reflects the first mirror surface and the second mirror surface in this order.
  • optically assisted magnetic head according to claim 1, wherein the optical element is a prism, and each of the mirror surfaces is an inner surface of the prism.
  • optically assisted magnetic head according to claim 1, wherein the optical element is a prism, and each of the mirror surfaces is an outer surface of the prism.
  • the optical element comprises a plurality of mirrors; 4.
  • the optical element is a prism having a first mirror surface and a second mirror surface on the inner surface, and light from the light source reflects the first mirror surface and the second mirror surface in this order,
  • the predetermined angle is ⁇
  • an angle formed by a surface on which light enters the prism and a surface on which light is emitted from the prism is (180 ° ⁇ ), and the first mirror surface and 2.
  • the optically assisted magnetic head as described in 1 above, wherein the optically assisted magnetic head has a size twice the angle formed by the second mirror surface.
  • An optically assisted magnetic recording apparatus comprising the optically assisted magnetic head according to any one of 1 to 8 above.
  • An optically assisted magnetic recording apparatus can be provided.
  • FIG. 1 is a schematic configuration diagram of an optically assisted magnetic recording apparatus equipped with an optically assisted magnetic head 3.
  • FIG. 3 is an exploded perspective view of the optically assisted magnetic head 3 and the head support portion 4.
  • FIG. 3 is a cross-sectional view of the optically assisted magnetic head 3 of FIG. 2 as viewed in the direction of an arrow by cutting along a plane including an II line.
  • 3 is a perspective view of an optical element 31.
  • FIG. It is a schematic diagram of the planar waveguide 32a.
  • FIG. 4A is an example of an optical path diagram of the optical element 31.
  • FIG. 5A is an optical path diagram when the light incident angle is changed
  • FIG. 5B is an optical path diagram when the optical element is rotated
  • FIG. 5F is an optical path diagram of the projection of the prism 311 ′ onto the yz plane when the prism 311 ′ having the roof mirror DM rotates on the yz plane.
  • it is an optical path diagram to the planar waveguide 32a when the diffraction grating G1 is formed on one surface of the prism 311.
  • FIG. 6 is an optical path diagram showing another example (a) and (b) of the optical element 31.
  • FIG. 2A is a cross-sectional view of the function of the lens group 50, in which FIG. 2A is a cross-sectional view of the optically assisted magnetic head 3 of FIG. (B) is an optical path diagram of the LD 33, (c) is an optical path diagram of the lens group 50 viewed from the z direction, and (d) is an optical path diagram of the lens group 50 viewed from the x direction. It is a figure for demonstrating step 1, 2, 3 of the manufacturing method of the prism 312 using anisotropic etching.
  • FIG. 6 is a cross-sectional view of an optically assisted magnetic head 8 according to a second embodiment, cut along a plane including the line II in FIG. It is a schematic diagram of the planar waveguide 32b.
  • FIGS. 3 and 9A It is a schematic diagram of the incident end of the planar waveguide 32b. It is sectional drawing of the prism 311 which concerns on an Example. It is sectional drawing of the mirror 80 which concerns on a comparative example. The state where the lens 29 or the lens group 50 is omitted from the optically assisted magnetic head 3 shown in FIGS. 3 and 9A is shown.
  • FIG. 1 shows a schematic configuration of an optically assisted magnetic recording device (for example, a hard disk device) 1 equipped with an optically assisted magnetic head 3.
  • an optically assisted magnetic recording device for example, a hard disk device
  • the optically assisted magnetic recording apparatus 1 includes a plurality of rotatable disks (magnetic recording media) 2 for recording, a head support unit 4, a tracking actuator 6, an optically assisted magnetic head 3, and a drive device (not shown). Are provided in the housing 1A.
  • the head support portion 4 is provided to be rotatable in the direction of arrow A (tracking direction) with the support shaft 5 as a fulcrum.
  • the optically assisted magnetic head 3 is an optical head that uses light for information recording on the disk 2.
  • the tracking actuator 6 is attached to the head support 4.
  • the optically assisted magnetic head 3 is attached to the tip of the head support 4.
  • a drive device (not shown) rotates the disk 2 in the direction of arrow B.
  • the optically assisted magnetic recording apparatus 1 is configured such that the optically assisted magnetic head 3 can move relative to the upper surface (or lower surface) of the disk 2 while floating.
  • FIG. 2 is an exploded perspective view of the optically assisted magnetic head 3 and the head support 4.
  • FIG. 3 is a cross-sectional view of the optically assisted magnetic head 3 of FIG. 2 cut along a plane including the line II and viewed in the direction of the arrow.
  • the head support portion 4 includes a suspension arm 41 having one end attached to the support shaft 5 and a flexure (plate spring) 44.
  • the suspension arm 41 and the flexure 44 are fixed by welding or the like.
  • a rectangular opening 42 is formed at the tip of the suspension arm 41.
  • a pivot (protruding portion) 43 that protrudes toward the inside of the opening 42 is provided on one side of the opening 42.
  • a rectangular opening 45 is formed at the tip of the flexure 44.
  • a tongue piece 46 having a flat surface protrudes from one side of the opening 45 so as to protrude into the inside.
  • the tongue piece portion 46 has a joint surface 46a that is projected to be inclined with respect to the opening portion 42 and then bent so as to be substantially horizontal.
  • the optically assisted magnetic head 3 includes a slider 32, a rectangular plate-shaped LD 33 disposed on the slider 32, a lens 29, a planar waveguide 32a (optical waveguide), and the optical element 31 according to the present invention.
  • the lower surface of the joint surface 46 a of the flexure 44 is bonded to the upper surface of the LD 33 so that the optically assisted magnetic head 3 is fixed to the tip of the suspension arm 41. I can't.
  • the planar waveguide 32 a is provided below the optical element 31 and on the side surface of the slider 32.
  • a magnetic recording unit and a magnetic reproducing unit (not shown) are provided in the vicinity of the planar waveguide 32a.
  • the LD 33 emits light used for information recording on the disk 2.
  • the LD 33 is arranged with the laser beam exit 33 a facing the first mirror surface M 1 of the optical element 31.
  • the wavelength of light emitted from the LD 33 is preferably from visible light to near infrared.
  • the specific wavelength band is about 0.6 ⁇ m to 2 ⁇ m, and more specific wavelengths include 650 nm, 830 nm, 1310 nm, 1550 nm, and the like.
  • the lens 29 has a function of condensing the light from the LD 33 in at least one direction on the vertical plane of the same optical axis, reduces the divergence angle of the light from the LD 33, makes parallel light, converges light, etc. It has the function of.
  • FIG. 4 is a perspective view of the optical element 31.
  • an optical element 31 is a reflection optical system including a first mirror surface M1 and a second mirror surface M2 that reflect light.
  • the present invention is not limited to the pentaprism as shown in FIG. Details of the optical element 31 will be described later.
  • the surface of the slider 32 facing the disk 2 (the lower surface in FIG. 3) is an air bearing surface (ABS: Air Bearing Surface) for improving the floating characteristics, and forms a groove 32g for capturing the floating air.
  • ABS Air Bearing Surface
  • FIG. 5 is a schematic diagram of the planar waveguide 32a
  • FIG. 5 (a) is a schematic diagram of the planar waveguide 32a viewed from the y direction
  • FIG. 5 (b) is a planar waveguide viewed from the x direction. It is a schematic diagram of the waveguide 32a.
  • the planar waveguide 32a includes a waveguide W having a condensing function by a curved reflecting surface having a partially elliptical shape, and a coupling portion d1 for coupling light to the waveguide W.
  • the coupling part d1 is a diffractive functional element that generates diffracted light.
  • the diffraction function element is an optical element that generates diffracted light, and for example, a diffraction grating (grating) is preferably used.
  • grating diffraction grating
  • the waveguide W is composed of a high refractive index layer HL stacked on a substrate and a low refractive index layer LL stacked around the high refractive index layer HL.
  • the boundary surface between the high refractive index layer HL and the low refractive index layer LL forms a part of a substantially elliptical surface.
  • the guided light is condensed by the reflection action at the interface between the high refractive index layer HL and the low refractive index layer LL.
  • the interface between the high refractive index layer HL and the low refractive index layer LL is configured to cause total reflection due to the difference in refractive index. Since the boundary surface forms a part of a substantially elliptical surface, when divergent light enters the planar waveguide 32a, a light source image is formed at the focal position of the substantially elliptical surface. That is, in the planar waveguide 32a, a laser beam can be condensed in one direction by a mirror effect using total reflection, and a minute light spot can be formed.
  • the high refractive index layer HL and the low refractive index layer LL may have a structure that gives a difference in refractive index depending on the refractive index of the material, or a structure that gives a difference in equivalent refractive index. . Therefore, even if the refractive index of the material of the high refractive index layer HL and the low refractive index layer LL is the same, changing the thickness of the waveguide layer gives a difference in the equivalent refractive index and reflects the guided light. It is also possible.
  • FIG. 6 is an example of an optical path diagram of the optical element 31.
  • 6A is an optical path diagram when the light incident angle is changed
  • FIG. 6B is an optical path diagram when the optical element 31 is rotated
  • FIG. 6C is an optical path diagram.
  • FIG. 11 is an optical path diagram when the element 31 is an internally reflecting prism 311.
  • FIG. 6D is an optical path diagram in the case where the optical element 31 is an external reflection prism 312.
  • the optical element 31 is a reflection optical system that includes two or more mirror surfaces and bends the direction of light emitted from the light source by a predetermined angle.
  • the optical element 31 has a function of reflecting incident light twice in order.
  • the optical element 31 includes two mirrors, a mirror M11 and a mirror M22.
  • the mirror M11 and the mirror M22 are drawn as planes, but may be curved surfaces.
  • the mirror M11 and the mirror M22 are arranged so as to form a crossing angle of the mirror having an angle ⁇ 2 on the yz plane in the coordinate system of FIG.
  • a light source not shown
  • the light L1 is reflected by the mirror M11 and the mirror M22 in this order, and becomes light L3.
  • the angle formed by the light L1 and the light L3, that is, the bending angle ⁇ 1 and the angle ⁇ 2 have the relationship of the following relational expression (1).
  • the mirror M11 rotates around the rotation axis (not shown) and is arranged at the position of the mirror M11 ′, and the mirror M22 rotates around the rotation axis to mirror the mirror. Even if it is arranged at the position of M22 ′, it can be said that the angle formed by the light L1 and the light L3 in which the light L1 mirror sequentially reflects M11 ′ and the mirror M22 ′ is constant.
  • the angle ⁇ 1 is desired to be 80 °
  • the angle ⁇ 2 is 50 ° from the relational expression (1).
  • ⁇ 1 90 °.
  • the optical element 31 having such a function, even if the optical element 31 rotates in the yz plane, the light bending angle does not change, and the positional deviation of the light with respect to the planar waveguide 32a hardly occurs.
  • the mirror M11 and the mirror M22 are curved surfaces.
  • the mirror M11 and the mirror M22 are not limited to planes.
  • optical element 31 having such a function an element obtained by integrating the two mirrors M11 and M22 shown in FIG. 6A with a holding structure (not shown) may be used, or a prism shape may be used.
  • the prism-shaped optical element 31 preferably employs one of the two shapes described below.
  • the first prism 311 is shown in FIG. 4 and is a type that reflects incident light on the inner surface.
  • the prism 311 includes a first mirror surface M1 and a second mirror surface M2 corresponding to the mirror M11 and the mirror M22, respectively.
  • the surface on which the light L1 enters the prism 311 is S1, the surface on which the light L3 exits the prism 311 is S2, the angle at which the light L1 enters the surface S1 is ⁇ 3 , and the angle at which the light L3 exits the surface S2 is ⁇ 4.
  • ⁇ 3 is 90 °
  • ⁇ 4 is also 90 °.
  • the wavelength of light from the light source may fluctuate due to environmental temperature changes or drive current changes. Therefore, in the prism 311 as well, it is necessary to consider that the emission direction of the light L3 emitted from the prism 311 does not change when the wavelength variation occurs in the incident light L1.
  • the angle K1 sandwiched between the surfaces S1 and S2 may be 180 ° ⁇ 1 .
  • ⁇ 3 and ⁇ 4 are not 90 °, the direction of change of ⁇ 3 and ⁇ 4 is reversed even when ⁇ 3 and ⁇ 4 are changed due to the change of the wavelength of the light L1.
  • ⁇ 3 and ⁇ 4 may be set. This is also desirable because the position of the light coupled to the planar waveguide 32a is stabilized.
  • the prism 311 is a type that internally reflects incident light twice, but may be a prism 311 ′ having a roof mirror DM as shown in FIG.
  • the Dach mirror DM may be used for either the first mirror surface M1 or the second mirror surface M2.
  • a roof mirror DM is used instead of the second mirror surface M2.
  • the Dach mirror DM is a roof-type mirror having two mirrors DM1 and DM2.
  • FIG. 6F shows an optical path diagram of projection of the prism 311 ′ onto the yz plane when the prism 311 ′ including the roof mirror DM rotates on the yz plane.
  • the light reflection function can be regarded as one time in the roof mirror DM. Therefore, in the prism 311 ′ including the roof mirror DM, it can be considered that the light is reflected once twice by the first mirror surface M 1 and once by the roof mirror DM once in the yz plane.
  • the second prism 312 is a type that reflects incident light to the outside.
  • the prism 311 in FIG. 6C is a prism having a first mirror surface M1 and a second mirror surface M2 corresponding to the mirror M11 and the mirror M22 on the inner surface, but the prism 312 is shown in FIG. As described above, the prism includes a first mirror surface M1 and a second mirror surface M2 corresponding to the mirror M11 and the mirror M22 on the outer surface.
  • the angle ⁇ 2 of the crossing angle of the mirror is less likely to change due to environmental changes and secular changes, and is stable.
  • FIG. 7 is an optical path diagram to the planar waveguide 32a when the diffraction grating G1 is formed on one surface of the prism 311 as an example.
  • the wavelength of light from a light source such as an LD may change due to an environmental temperature change or a drive current change.
  • a diffraction grating is used for the coupling part d1 of the planar waveguide 32a, the incident angle from the diffraction grating to the waveguide W depends on the wavelength, so that the wavelength change of the light source leads to a change in the coupling efficiency to the waveguide W. It becomes a malfunction. Therefore, by forming the diffraction grating G1 on one surface of the prism 311, it is possible to cancel the diffraction angle change in the diffraction grating G1 at the time of wavelength change and the change in the incident angle to the waveguide W in the coupling part d1. Become.
  • the diffraction grating G1 is set so that the diffraction angle ⁇ 2 is larger than the incident angle ⁇ 1. Then, for example, when the wavelength increases, ⁇ 2 increases, and the incident angle ⁇ of the light L3 with respect to the coupling portion d1 of the planar waveguide 32a decreases. However, since the wavelength is small, the angle at which the light L3 enters the waveguide W is large. As a result, the light L3 is coupled in the waveguide mode without being in the radiation mode in the waveguide W, and the coupling efficiency is kept constant.
  • FIG. 8 is another example of an optical path diagram of the optical element 31.
  • FIG. 8A shows another example of the arrangement of the mirror M11 and the mirror M22.
  • the arrangement of the mirror M11 and the mirror M22 described with reference to FIG. 6A is such that the light L3 emitted from the optical element 31 is reflected in the direction of the light L1 incident on the optical element 31.
  • the arrangement of the mirror M11 and the mirror M22 shown in FIG. 8A the light L3 emitted from the optical element 31 is emitted in the direction of the light L1 incident on the optical element 31.
  • the angle ⁇ 1 of the bending angle and the angle ⁇ 2 have the relationship of the following relational expression (2).
  • FIG. 8B is an example of an optical system of the optical element 31 having a function of reflecting incident light four times in order.
  • the mirrors M11, M22, M3, and M4 can be arranged so that the angle formed by the light L3 and the light L1 is 90 degrees.
  • a lens group 50 composed of a plurality of lenses may be adopted as will be described next.
  • FIG. 9 is an explanatory diagram of the function of the lens group 50.
  • FIG. 9A is a cross-sectional view of the optically assisted magnetic head 3 of FIG. 2 cut along a plane including the line II and viewed in the direction of the arrow when the lens group 50 is used.
  • FIG. 9B is an optical path diagram of the LD 33.
  • FIG. 9C is an optical path diagram when the lens group 50 is viewed from the z direction.
  • FIG. 9D is an optical path diagram when the lens group 50 is viewed from the x direction.
  • the lens group 50 includes a collimating lens 52 and a beam expander optical system 51.
  • the beam expander optical system 51 includes a lens 51a that is a concave cylindrical lens and a lens 51b that is a convex cylindrical lens, and is an optical system that performs beam expansion only in one direction within the optical axis cross section of incident light.
  • light from the exit 33a of the LD 33 is collimated by the collimating lens 52, diverged in the xy plane by the lens 51a, and collimated in the xy plane by the lens 51b.
  • the light from the exit 33a of the LD 33 is collimated by the collimating lens 52, and the lens 51a and the lens 51b have no power in the xy plane.
  • the light is emitted as it is.
  • the light diameter in the xy plane and the light diameter in the yz plane can be shaped to a desired size. Accordingly, it is possible to optimize the utilization efficiency of light coupled to the planar waveguide 32a.
  • the lens 29 or the lens group 50 between LD33 and the optical element 31 has been shown so far, the lens 29 or the lens group 50 does not necessarily need to be used as shown in FIG.
  • FIG. 16 shows a state where the lens 29 or the lens group 50 is omitted from the optically assisted magnetic head 3 shown in FIGS. 3 and 9A. Also in the case of the optically assisted magnetic head 3 that does not use the lens 29, all the light rays that are emitted from the LD 29 and incident on the optical element 31 are fixed to each other, for example, in FIGS. 2 (a) to 2 (d). Even if the mirrors M11 and M22 are rotated in the yz plane, the light bending angle ⁇ 1 is not changed.
  • the light emitted from the LD 33 is reflected twice by the optical element 31 as described above, folded back by a predetermined angle in the yz plane, deflected in the z direction, and condensed by the lens group 50, and reaches the coupling portion d1.
  • the light enters the planar waveguide 32a.
  • the planar waveguide 32a At the exit end of the planar waveguide 32a, light is sufficiently focused in both the x and y directions, and a plasmon probe (not shown) formed on the exit end face of the waveguide is irradiated to generate near-field light from the plasmon probe.
  • the disk 2 is heated by the near-field light, the coercive force is lowered, and magnetic information is recorded by a magnetic recording unit (not shown).
  • the disk 2 moves from the optically assisted magnetic head 3 and is cooled, the coercive force is restored and magnetic information is retained.
  • the material of the optical element 31 is a transparent material such as plastic or glass.
  • the optical element 31 is produced by, for example, injection molding, imprint manufacturing, extrusion molding, or glass molding.
  • the resin for injection molding include polycarbonate (for example, AD5503, Teijin Chemicals Limited) and ZEONEX 480R (Nippon Zeon Corporation), which are thermoplastic resins.
  • the resin for imprint manufacturing include PAK-02 (Toyo Gosei Co., Ltd.), which is a photocurable resin.
  • FIG. 10 is an explanatory diagram of a method for manufacturing the prism 312 using anisotropic etching.
  • Anisotropic etching is a method for producing two surfaces that intersect at a predetermined angle by utilizing the fact that the etching rate differs for each crystal orientation plane in a crystal.
  • a manufacturing method for manufacturing the optical element 31 having a prism angle of about 70.5 ° using single crystal silicon will be taken as an example.
  • the ratio of the etching rates of ⁇ 100> and ⁇ 111> is 400: 1. With this speed ratio, two planes inclined relatively by 70.5 ° can be obtained.
  • step 1 first, a single crystal silicon plate 60 having a crystal orientation of ⁇ 100> is prepared. Next, in addition to the etched surface, for example, a silicon nitride mask 61 is applied as an etching mask. In order to fabricate the silicon nitride mask 61, a single crystal silicon plate 60 is placed for a predetermined time under a high temperature in a nitrogen atmosphere, and silicon nitride is grown on the entire surface, and then the predetermined shape is etched by photolithography. To do.
  • step 2 the intermediate produced in step 1 is immersed in a potassium hydroxide etching bath (not shown), and the single crystal silicon exposed from the silicon nitride mask 61 is anisotropically etched.
  • step 3 the silicon nitride mask 61 is removed from the intermediate obtained in step 2 by etching, and then cut into a predetermined size using a dicing saw or the like. Through the above steps, the optical element 31 having a predetermined shape can be obtained.
  • the manufacturing method of the optical element 31 having a prism angle of about 70.5 ° is taken as an example.
  • the prism angle can be set variously depending on the orientation of the single crystal silicon. Single crystal silicon that matches the required prism angle may be used.
  • the difference from the first embodiment is that direct coupling is performed as coupling of light to the waveguide.
  • the coupling part d1 of the planar waveguide 32a in the first embodiment includes a diffraction function element. If a diffractive functional element is used for the coupling part d1, the light from the LD 33 can be easily coupled to the planar waveguide 32a with a rough assembly adjustment accuracy.
  • the coupling part d1 since the coupling part d1 is directly coupled to the planar waveguide 32a without using a diffraction function element, adjustment accuracy is required, but since a diffraction function element is not used, it is necessary to manufacture a diffraction function element. Thus, an optically assisted magnetic head can be manufactured at low cost. Further, the coupling efficiency can be improved as compared with the case where the diffraction function element is used.
  • FIG. 11 is a cross-sectional view of the optically assisted magnetic head 8 according to the second embodiment cut along a plane including the line II in FIG. 2 and viewed in the direction of the arrow.
  • FIG. 12 is a schematic diagram of the planar waveguide 32b.
  • FIG. 13 is a schematic view of the incident end of the planar waveguide 32b.
  • optically assisted magnetic head 8 includes a planar waveguide 32b instead of the planar waveguide 32a, and the optical element 31 is directly disposed on the slider 32. It is a point.
  • the planar waveguide 32b (optical waveguide) includes a high-refractive index layer HL and a low-refractive index layer LL stacked on a substrate, like the planar waveguide 32a.
  • the waveguide structure and the function of condensing light are the same as those of the planar waveguide 32a.
  • the planar waveguide 32b does not have the coupling portion d1 unlike the planar waveguide 32b, but instead includes an incident end 70 that performs direct coupling.
  • the optical element 31 is disposed directly on the slider 32.
  • the light from the LD 33 is bent by the optical element 31 at a predetermined angle of 90 °.
  • the light coupling to the planar waveguide 32 b is perpendicularly incident on the incident end 70, and therefore a spot having a flatter cross section as compared with the case of the first embodiment.
  • Beam shaping is performed to form
  • the light emitted from the LD 33 passes through the lens group 50 and the optical element 31 and is condensed on the incident end 70 having a flat shape as shown in FIGS. Then, the light from the LD is beam-shaped by the lens group 50 so that the coupling efficiency to the incident end 70 is increased, and becomes a flat shape like the beam 500.
  • the light emitted from the LD 33 is reflected twice by the optical element 31 as described above, folded back by a predetermined angle in the yz plane, deflected in the z direction, and condensed by the lens group 50, and incident on the planar waveguide 32b. Is done.
  • the planar waveguide 32b At the exit end of the planar waveguide 32b, light is sufficiently narrowed in both the x and y directions, and a plasmon probe (not shown) formed on the exit end face of the waveguide is irradiated to generate near-field light from the plasmon probe.
  • the disk 2 is heated by the near-field light, the coercive force is lowered, and magnetic information is recorded by a magnetic recording unit (not shown).
  • the disk 2 is moved from the optically assisted magnetic head 8 and cooled, the coercive force is recovered and magnetic information is held.
  • optical element 31 in the optically assisted magnetic heads 3 and 8 of the present invention examples are shown below.
  • FIG. 14 is a cross-sectional view of the prism 311 according to the embodiment
  • FIG. 15 is a cross-sectional view of a mirror 80 according to the comparative example.
  • the unit of length in FIGS. 14 and 15 is ⁇ m.
  • the optically assisted magnetic heads 3 and 8 are very small, and the prism 311 and the mirror 80 are also on the order of ⁇ m.
  • Table 1 shows the calculation results of the values of the tilt angle and the shift amount of the reflected light when the prism 311 and the mirror 80 cause a mounting angle shift of 1 degree in the yz plane in both the example and the comparative example.
  • the rotation axis O1 of the prism 311 in FIG. 14 is the intersection of the optical axis of the light and the surface S1 on which the light is incident.
  • the rotation axis O2 of the mirror 80 in FIG. 15 is the intersection of the optical axis of the light and the reflection surface of the mirror 80.
  • a shift amount of 0.87 ⁇ m is generated at the incident end of the planar waveguide with respect to the mounting angle deviation per degree.
  • the shift amount is only 0.57 ⁇ m at the incident end of the planar waveguide with respect to the mounting angle deviation per degree.
  • the thickness of the waveguide layer of the planar waveguide 32b depends on the refractive index difference of the cladding of the waveguide layer, but is several times the wavelength used. For example, when light having a wavelength of 830 nm is used, the thickness of the waveguide layer is several ⁇ m.
  • the allowable value of the positional deviation of the optical axis of the light with respect to the optical axis of the waveguide layer needs to be suppressed within about 1 ⁇ m. Therefore, by adopting the prism 311 of this embodiment, it is possible to achieve the allowable value of this positional deviation.
  • the area of the coupling part d1 provided with the diffraction grating is as wide as several tens of ⁇ m to 100 ⁇ m, as disclosed in paragraph [0046] of JP 2010-182394 A. Therefore, although the influence of the shift of the light beam in the coupling part d1 is not large, this embodiment is preferable in that the shift that deteriorates the light coupling efficiency can be reduced compared to the mirror 80.
  • the influence of the tilt is larger than the influence of the shift for the coupling part d1 including the diffraction grating.
  • the mirror 80 of the comparative example having a large tilt angle when the mounting angle is shifted by 0.25 degrees, the incident angle is shifted by 0.5 degrees from the optimum incident angle, and the coupling efficiency is reduced by 50%.
  • the light flux can be guided to the waveguide at a predetermined incident angle without depending on the mounting angle deviation of the prism 311. Therefore, there is no change in the coupling efficiency, and the assembly adjustment at the time of manufacture is not required It becomes very easy to implement.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Recording Or Reproducing By Magnetic Means (AREA)
  • Magnetic Heads (AREA)

Abstract

L'invention concerne une tête magnétique à assistance lumineuse et un dispositif d'enregistrement magnétique à assistance lumineuse dans lesquels la résistance aux modifications environnementales et chronologiques est élevée et qui améliorent la productivité de masse en essayant de réduire considérablement la précision d'une étape de guidage de la lumière entre une source de lumière et un capteur plasmonique, raccourcissent le temps de fabrication et augmentent le rendement. Cette tête magnétique à assistance lumineuse est équipée d'une source de lumière et d'un guide d'ondes optique dans lequel est couplée la lumière provenant de la source de lumière, un capteur plasmonique étant disposé à une extrémité de sortie du guide d'ondes optique. La tête magnétique à assistance lumineuse est munie d'un élément optique doté d'une pluralité de surfaces réfléchissante sur le trajet entre la source de lumière et le guide d'ondes optique, l'élément optique étant adapté pour dévier selon un angle prédéterminé, par réflexion sur la pluralité de surfaces réfléchissantes, la direction de la lumière qui sort de la source de lumière; la tête magnétique à assistance lumineuse provoquant le couplage direct de la lumière sortant de l'élément optique dans le guide d'ondes optique.
PCT/JP2012/056821 2011-03-22 2012-03-16 Tête magnétique à assistance lumineuse et dispositif d'enregistrement magnétique à assistance lumineuse WO2012128198A1 (fr)

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JP2011061909A JP2014112452A (ja) 2011-03-22 2011-03-22 光アシスト磁気ヘッド及び光アシスト磁気記録装置
JP2011-061909 2011-03-22

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WO2012128198A1 true WO2012128198A1 (fr) 2012-09-27

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007310958A (ja) * 2006-05-18 2007-11-29 Konica Minolta Opto Inc 光記録ヘッド及び光記録装置
WO2009057429A1 (fr) * 2007-10-29 2009-05-07 Konica Minolta Opto, Inc. Tête optique et dispositif d'enregistrement optique

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007310958A (ja) * 2006-05-18 2007-11-29 Konica Minolta Opto Inc 光記録ヘッド及び光記録装置
WO2009057429A1 (fr) * 2007-10-29 2009-05-07 Konica Minolta Opto, Inc. Tête optique et dispositif d'enregistrement optique

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