JP2006099938A - Near-field optical head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a constitution for making a near-field light-generating element adjacent to a recording medium, by securing reliability of connection of a near-field optical head and an optical fiber with each other. <P>SOLUTION: The near-field optical head 106 consists of a mirror substrate 202 having a V groove 208 for fixing an optical fiber 103; and a slider substrate 201 having the near-field light generating element 205. The area of the mirror substrate 202 is larger than that of the slider substrate 201. Thus, the mirror substrate 202 has a first projecting part 210 on the insertion side of an optical fiber 103 and a second projecting part 211 on the side of a flow outlet end 204. The V groove 208 and a mirror 209 are formed on the first projecting part 210 and the second projecting part 211, as well. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a near-field optical head that records and reproduces information at a recording density exceeding the diffraction limit of light.

  For information recording / reproducing apparatuses that are increasing in capacity and downsizing, a recording / reproducing technique capable of obtaining a higher recording density is required. Information recording / reproducing technology using near-field light can handle optical information in a minute area exceeding the diffraction limit of light, so that it is possible to obtain a high recording density that cannot be achieved by conventional recording / reproducing technology using light. Expected.

In general, the configuration of a recording / reproducing apparatus using near-field light is almost the same as that of a magnetic disk apparatus (HDD), but it is composed of optical minute apertures, minute protrusions, etc. instead of magnetic elements such as GMR elements and coils. The difference is that the near-field light generating element is mounted on the flying head slider and an optical fiber or an optical waveguide is incorporated instead of the electric wiring. (See, for example, Patent Document 1.) How to efficiently guide light to the near-field light generating element and the recording medium using an optical fiber or an optical waveguide having a lower degree of freedom of wiring than electrical wiring. In such a near-field optical head, which is an important element of recording / reproducing technology, an optical fiber or optical waveguide is connected to the side of the head, and light from the optical fiber or optical waveguide propagating in the horizontal direction to the media surface is transmitted. A technique has been devised in which a minute beam spot is made incident on an optical minute aperture by using a light reflecting surface that reflects and directs the propagation direction to the aperture direction. (See Patent Document 1.)
FIG. 7 is a three-view diagram of a typical structure of a near-field optical head 1000 according to the prior art. The near-field optical head 1000 has a structure in which a mirror substrate 1001 and a slider substrate 1002 are bonded, and an optical fiber 103 is sandwiched between the two substrates. The mirror substrate 1001 is made of silicon and has a V-groove 1003 and a mirror 1004. Both the V-groove 1003 and the mirror 1004 are formed of a surface formed by silicon crystal anisotropic etching and having an angle of about 55 degrees from the substrate surface. The optical fiber 103 is fixed to the V groove 1003 and bonded. The slider substrate 1002 is made of glass, has a lens 1005 on its upper surface, and has an air bearing surface (ABS) 1006 and a near-field light generating element 1007 on its lower surface.

The near-field light generating element 1007 has one or more elements such as an optical minute aperture, a minute protrusion, a metal thin film having a thickness of several to several hundreds nm, and a minute scatterer. Light from a laser (not shown) is introduced into the near-field optical head 1000 by the optical fiber 103, reflected by the mirror surface 1004 from the end face of the optical fiber 103, condensed by the lens 1005, and near-field light generating element 1007. To. A part of the light energy is distributed as near-field light from the near-field light generating element 1007. This near-field light is allowed to interact with a data mark on the surface of the recording medium (not shown), and the scattered light generated as a result is detected, thereby enabling high-density information recording / reproduction.
International Patent Publication No. 00/28536 pamphlet (pages 41-46, Fig. 5-6)

  However, in the near-field optical head according to the above-described prior art, the optical fiber 103 and the V-groove 1003 are bonded, but the bonding margin is not always sufficient, which is serious particularly when the size of the near-field optical head is reduced. It becomes a problem. In the near-field optical head 1000 shown in FIG. 7, the bonding margin is less than half of one side of the near-field optical head 1000. If the bonding margin is not sufficient, the optical fiber 103 is easily peeled off from the near-field optical head 1000, and in this case, the operation of the information recording / reproducing apparatus is fatally affected.

  In addition, the near-field optical head that floats by the air flying force from the rotating disk is actually slightly inclined, and the outflow end is closer to the disk surface than the inflow end of air. Since the near-field light attenuates exponentially with the distance from the opening, it is desirable that the near-field light generating element 1007 be as close to the disk surface as possible. That is, the near-field light generating element 1007 is preferably brought closer to the outflow end. When the near-field light generating element 1007 is at a position away from the disk surface, the near-field light from the near-field light generating element 1007 spreads weakly on the disk that is the recording medium, and the detection signal S / N deteriorates. Moreover, the problem that density increase becomes difficult is produced.

  However, with the near-field optical head according to the prior art, it is difficult to bring the near-field light generating element 1007 close to the outflow end. As shown in FIG. 7, since the V-groove 1003 and the mirror 1004 are structures in the mirror substrate 1002, they are included in the near-field optical head 1000. Therefore, the light spot from the optical fiber 103 fixed to the V-groove 1003 to the surface of the aperture substrate 1001 via the mirror 1004 and the lens 1005 is at least half the width of the V-groove 1003 from the end of the near-field optical head 1000. The near field light generating element 1007 provided at the spot cannot be brought close to the outflow end.

  A first aspect of the present invention that solves the above problems includes a first substrate having a near-field light generating element that generates near-field light, and a support groove provided on the first substrate and fixing an optical fiber. A near-field optical head comprising a second substrate having the second substrate, wherein the second substrate has a projecting portion projecting from the first substrate.

  Such an overhanging portion makes the area of the surface of the second substrate facing the first substrate larger than the area of the surface of the first substrate facing the second substrate. The substrate is offset and fixed, the contour shape of the surface of the first substrate facing the second substrate is made different from the contour shape of the surface of the second substrate facing the first substrate, etc. It is characterized by using a technique.

  According to a second aspect of the present invention, there is provided a near-field optical head according to the first aspect, wherein a part or all of a support groove is provided in the projecting portion.

  According to a third aspect of the present invention, there is provided a near-field optical head according to the first or second aspect, wherein the support groove and the optical fiber are fixed using an adhesive.

  A fourth aspect of the present invention is the near-field optical head according to any one of the first to third aspects, wherein the support groove is a V-groove.

  A fifth aspect of the present invention is a near-field optical head according to any one of the first to fourth aspects, wherein one side surface of the support groove is a reflecting surface.

  According to a sixth aspect of the present invention, there is provided a near-field optical head according to the fifth aspect, wherein a part or all of the reflecting surface is provided on the projecting portion.

  According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the near-field optical head that floats on air, wherein a line connecting the outflow end and the inflow end and the support groove are substantially orthogonal to each other. It is in the near-field optical head.

  According to an eighth aspect of the present invention, in any one of the first to sixth aspects, the near-field optical head that floats in air, wherein a line connecting the outflow end and the inflow end and the support groove are substantially parallel. It is in the characteristic near-field optical head.

  A ninth aspect of the present invention is the near-field optical head according to any one of the first to eighth aspects, wherein the end face of the optical fiber is substantially perpendicular to the axial direction of the optical fiber.

  A tenth aspect of the present invention is the near-field optical head according to any one of the first to eighth aspects, wherein the end face of the optical fiber is inclined with respect to the axial direction of the optical fiber. .

  As described above, according to the present invention, since the near-field optical head has the overhanging portion, it is possible to sufficiently secure the length of the support groove, that is, sufficiently secure the margin for fixing the support groove and the optical fiber. I can do it. Thereby, it is possible to easily ensure the reliability of the connection between the near-field optical head and the optical fiber, which becomes a problem particularly when the near-field optical head is downsized.

  Further, according to the present invention, the near-field optical head has the projecting portion, and the support groove is applied to the projecting portion, whereby the optical fiber can be brought close to the outflow end. As a result, the near-field light generating element can be provided in the vicinity of the outflow end, so that the near-field light generating element can be brought closer to the surface of the recording disk, and the near-field light with high intensity and fine localization can be obtained. By interacting with the recording disk via the, a near-field optical head having a good S / N of the detection signal and corresponding to a high recording density can be realized.

  Moreover, a part or all of the reflecting surface can be provided on the projecting portion. This also makes it possible to place the near-field light generating element in the vicinity of the outflow end.

  Further, according to the present invention, an adhesive can be used for fixing the support groove and the optical fiber, so that a near-field optical head can be easily manufactured.

  In addition, according to the present invention, the support groove is a V-groove, so that the optical fiber can be easily fixed with high positional accuracy.

  In addition, according to the present invention, since the end face of the optical fiber can be a vertical surface that can be easily processed, a high-performance near-field optical head can be easily realized.

The best mode for carrying out the present invention will be described below with reference to the drawings.
(Embodiment 1)
FIG. 1 shows an outline of an information recording / reproducing apparatus using a near-field optical head in Embodiment 1 of the present invention. The information recording / reproducing apparatus in the present embodiment is similar in basic structure to a conventional magnetic disk apparatus, and a near-field optical head 106 having a near-field light generating element (not shown) that generates near-field light is used as a recording medium 107. In order for the near-field optical head 106 to always float with the recording medium 107 at a fixed relative position, the flexure 105 is suspended from the suspension arm. It is formed at the tip of 104. The suspension arm 104 is movable in the radial direction of the recording medium 107 by a voice coil motor (not shown). Here, the near-field light head 106 is disposed so that the near-field light generating element faces the recording medium 107.

  The light propagation unit that guides the light beam from the laser 101 to the near-field optical head 106 includes an optical fiber 103 fixed to the lens 102 and the suspension arm 104.

  If necessary, the laser 101 can be intensity-modulated by the circuit system 108. In order to make the outline easy to understand, the suspension arm 104, the flexure 105, and the near-field optical head 106 are shown in an exploded form, but in actuality, they are connected and fixed as necessary.

  FIG. 2 shows a three-view diagram of the near-field optical head 106 and the optical fiber 103 and the flexure 105 fixed thereto in the first embodiment of the present invention. The near-field optical head 106 includes a slider substrate 201 made of glass and a mirror substrate 202 made of silicon.

  The slider substrate 201 is a rectangular substrate. One side of the lower surface of the slider substrate 201 is an inflow end 203 and the opposite side is an outflow end 204. The slider substrate 201 has a near-field light generating element 205 and two strip-shaped ABS (air bearing surface) 206 arranged in parallel on the lower surface thereof. The longitudinal direction of the ABS 206 is orthogonal to the inflow end 203 and the outflow end 204. The shape of the ABS 204 is not limited to two strip shapes, but may be a try pad shape. The near-field light generating element 102 has one or more elements such as an optical minute aperture, a minute protrusion, a metal thin film having a thickness of several to several hundreds nm, and a minute scatterer. Further, the slider substrate 201 has a lens 207 disposed on the upper surface thereof so as to face the near-field light generating element 203.

The mirror substrate 202 has a V-groove 208 on its lower surface. The V groove 208 starts from one side surface of the mirror substrate 202 and has an end in the mirror substrate 202, and this end surface is a mirror 209. Since the V-groove 206 and the mirror 207 are formed by crystal anisotropic etching, the mirror 207 forms an angle of about 55 degrees with respect to the mirror substrate 202 surface. The optical fiber 103 is fixed to the V groove 208. The upper surface of the slider substrate 201 and the lower surface of the mirror substrate 202 are bonded so that the inflow end 203 and the outflow end 204 are parallel to the optical fiber 103. The end face of the optical fiber 103 forms a plane of about 55 degrees with respect to the axis of the optical fiber 103. Therefore, the light emitted from the optical fiber 103 is bent by the mirror 209 and emitted perpendicularly to the mirror substrate 202. The light bent by the mirror 209 is guided to the near-field light generating element 205 through the lens 207.
A flexure 105 is bonded to the upper surface of the mirror substrate 202.

  The mirror substrate 202 has a larger area than the slider substrate 201. For this reason, the mirror substrate 202 has a first projecting portion 210 on the insertion side of the optical fiber 103 and a second projecting portion 211 on the outflow end 204 side. It is important that the V groove 208 and the mirror 209 are also formed on the first projecting portion 210 and the second projecting portion 211.

  In the present embodiment, the near-field optical head 106 has the first projecting portion 210, so that the length of the V-groove 208 is sufficiently secured, that is, the margin for bonding the V-groove 208 and the optical fiber 103 is sufficiently secured. I can do it. As a result, the reliability of the connection between the near-field optical head 106 and the optical fiber 103, which becomes a problem particularly when the near-field optical head 106 is downsized, can be easily ensured.

Further, the near-field optical head 106 has the second projecting portion 211, and the V-groove 208 is applied to the second projecting portion 211, whereby the optical fiber 103 can be brought closer to the outflow end 204. As a result, the near-field light generating element 205 can be provided in the vicinity of the outflow end 204, so that the near-field light generating element 205 can be brought closer to the surface of the recording disk, and has high strength and is finely localized. By interacting with the recording disk via near-field light, a near-field optical head having a good S / N of the detection signal and corresponding to a high recording density can be realized.
(Embodiment 2)
FIG. 3 is a diagram showing a configuration of a near-field optical head according to Embodiment 2 of the present invention. The upper figure is a side view of the near-field optical head, and the lower figure is a plan view.

  The near-field optical head here is almost the same as the near-field optical head according to the first embodiment. However, the difference is that the first projecting portion 302 constituting the mirror substrate 301 is notched except for the V groove 208, the mirror 209, and the vicinity thereof.

In the present embodiment, in addition to the effects of the first embodiment, the mass of the entire near-field optical head is reduced because the first overhanging portion 302 is reduced. Therefore, the near-field optical head can be moved at high speed, and an information recording / reproducing apparatus having a higher data transfer rate can be realized.
(Embodiment 3)
FIG. 4 is a diagram showing the configuration of a near-field optical head according to Embodiment 3 of the present invention. The upper figure is a side view of the near-field optical head, and the lower figure is a plan view.

  As in the first embodiment, the near-field optical head in the present embodiment includes a slider substrate 401 made of glass and a mirror substrate 402 made of silicon.

  Similarly to the first embodiment, the slider substrate 401 is a rectangular substrate, has an inflow end 403 and an outflow end 404, and similarly, two near-field light generating elements 205 are arranged in parallel. A strip-shaped ABS 406 and a lens 205 are provided.

  The mirror substrate 402 has a V-groove 408 and a mirror 409 as in the first embodiment, and the optical fiber 400 is fixed to the V-groove 408.

  Here, the point that the upper surface of the slider substrate 401 and the lower surface of the mirror substrate 402 are joined so that the inflow end 403 and the outflow end 404 are orthogonal to the optical fiber 400 is different from the first embodiment.

The end face of the optical fiber 400 is perpendicular to the axis of the optical fiber 400. Further, since the V groove 408 and the mirror 409 are formed by crystal anisotropic etching, the mirror 409 forms an angle of about 55 degrees with respect to the mirror substrate 402 surface. Therefore, when the light emitted from the optical fiber 400 is bent by the mirror 409, the light is inclined about 20 degrees toward the fiber 401 from the vertical. The light bent by the mirror 409 is guided to the near-field light generating element 405 through the lens 407.
As in the first embodiment, the flexure 105 is bonded to the upper surface of the mirror substrate 402.

  The mirror substrate 402 has a larger area than the slider substrate 401, and therefore, the mirror substrate 402 has an overhanging portion 410 on the outflow end 404 side. Here, it is important that the V groove 408 and the mirror 409 or the vicinity thereof are on the projecting portion 410.

  Further, similarly to the second embodiment, the protruding portion 410 may have a shape that is cut away leaving the V groove 408, the mirror 409, and the vicinity thereof.

  In the present embodiment, the near-field optical head has the protruding portion 410, and the V-groove 408 and the mirror 409, or their vicinity, are applied to the protruding portion 410, so that the optical fiber 400 can be brought close to the outflow end 404. . As a result, the near-field light generating element 405 can be provided in the vicinity of the outflow end 404, so that the near-field light generating element 405 can be brought closer to the surface of the recording disk, and has high strength and is finely localized. By interacting with the recording disk via near-field light, a near-field optical head having a good S / N of the detection signal and corresponding to a high recording density can be realized.

Further, since the end surface of the optical fiber 400 is a vertical surface that can be easily processed, a high-performance near-field optical head can be easily realized.
(Embodiment 4)
FIG. 5 is a diagram showing the configuration of a near-field optical head according to Embodiment 4 of the present invention. The upper figure is a side view of the near-field optical head, and the lower figure is a plan view.

The near-field optical head here is substantially the same as the near-field optical head according to the first embodiment, but differs in that a smaller head size is realized. The slider 501 in the present embodiment is smaller than the slider 201 in the first embodiment. The near-field light generating element 505 is provided between two strip-shaped ABSs 506a and ABS 506b arranged in parallel and closer to one ABS 506a. It has been. Therefore, although the slider 501 is smaller than the slider 201 in the first embodiment, the length of the V groove 508 can be sufficiently secured, that is, the margin for bonding the V groove 508 and the optical fiber 103 can be sufficiently secured. I can do it.
Also in this case, since the near-field optical head 506 has the first projecting portion 510, in addition to the above-described configuration, it contributes to sufficiently securing a bonding margin between the V groove 508 and the optical fiber 103. Of course.
(Embodiment 5)
FIG. 6 is a diagram showing a configuration of a near-field optical head according to the fifth embodiment of the present invention. The upper figure is a side view of the near-field optical head, and the lower figure is a plan view.

  The near-field optical head here is almost the same as the near-field optical head according to the first embodiment except that the area of the mirror substrate 602 and the area of the slider substrate 601 are equal. Since the mirror substrate 602 and the slider substrate 601 are bonded with an offset, the mirror substrate 602 has a first projecting portion 610 on the insertion side of the optical fiber 103 and a second projecting portion 611 on the outflow end 604 side. Have. As a result, a sufficient margin for bonding the V groove 608 and the optical fiber 103 can be secured.

It is the schematic of the information recording / reproducing apparatus using the near-field optical head concerning Embodiment 1 of this invention. It is a three-view figure of the near-field optical head concerning Embodiment 1 of this invention, the optical fiber fixed to it, and a flexure. It is a figure which shows the structure of the near-field optical head concerning Embodiment 2 of this invention. It is a figure which shows the structure of the near-field optical head concerning Embodiment 3 of this invention. It is a figure which shows the structure of the near-field optical head concerning Embodiment 4 of this invention. It is a figure which shows the structure of the near-field optical head concerning Embodiment 5 of this invention. It is a trihedral view showing the configuration of a near-field optical head according to the prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Laser 102 Lens 103 Optical fiber 104 Suspension arm 105 Flexure 106 Near field optical head 107 Recording medium 108 Circuit system 201 Slider substrate 202 Mirror substrate 203 Inflow end 204 Outflow end 205 Near field light generation element 206 ABS
207 Lens 208 V groove 209 Mirror 210 First overhanging portion 211 Second overhanging portion 301 Mirror substrate 302 First overhanging portion 400 Optical fiber 401 Slider substrate 402 Mirror substrate 403 Inflow end 404 Outflow end 405 Near-field light generating element 406 ABS
407 Lens 408 V groove 409 Mirror 410 Overhang portion 501 Slider substrate 502 Mirror substrate 503 Inflow end 504 Outflow end 505 Near-field light generating element 506a, b ABS
507 Lens 508 V groove 509 Mirror 510 First overhanging portion 511 Second overhanging portion 601 Slider substrate 602 Mirror substrate 603 Inflow end 604 Outflow end 605 Near-field light generating element 606 ABS
607 Lens 608 V-groove 609 Mirror 610 First overhang 611 Second overhang 1000 Near-field optical head 1001 Mirror substrate 1002 Slider substrate 1003 V-groove 1004 Mirror 1005 Lens 1006 ABS
1007 Near-field light generating element

Claims (13)

  A near-field optical head comprising a first substrate having a near-field light generating element for generating near-field light, and a second substrate provided on the first substrate and having a support groove for fixing an optical fiber. The near-field optical head according to claim 1, wherein the second substrate has a projecting portion projecting from the first substrate.   The near-field optical head according to claim 1, wherein a part or all of the support groove is provided in the projecting portion.   The near-field optical head according to claim 1, wherein the support groove and the optical fiber are fixed using an adhesive.   The near-field optical head according to claim 1, wherein the support groove is a V-groove.   5. The near-field optical head according to claim 1, wherein one side surface of the support groove is a reflection surface.   6. The near-field optical head according to claim 5, wherein a part or all of the reflecting surface is provided on the projecting portion.   7. The near-field optical head according to claim 1, wherein the near-field optical head floats in air, and the line connecting the outflow end and the inflow end is substantially orthogonal to the support groove.   The near-field optical head according to claim 1, wherein the near-field optical head floats on the air, and the line connecting the outflow end and the inflow end is substantially parallel to the support groove.   9. The near-field optical head according to claim 1, wherein an end face of the optical fiber is substantially perpendicular to an axial direction of the optical fiber.   The near-field optical head according to claim 1, wherein an end face of the optical fiber is inclined with respect to an axial direction of the optical fiber.   11. The area of the surface of the second substrate facing the first substrate is larger than the area of the surface of the first substrate facing the second substrate. The near-field optical head described in the above.   The contour shape of the surface of the first substrate facing the second substrate is substantially the same as the contour shape of the surface of the second substrate facing the first substrate, and the first substrate and the The near-field optical head according to claim 1, wherein the second substrate is offset and fixed.   The contour shape of the surface of the first substrate facing the second substrate is different from the contour shape of the surface of the second substrate facing the first substrate. The near-field optical head according to any one of the above.

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