CN100359578C - Solid immersion lens and method of manufacturing same - Google Patents
Solid immersion lens and method of manufacturing same Download PDFInfo
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- CN100359578C CN100359578C CNB2005101096356A CN200510109635A CN100359578C CN 100359578 C CN100359578 C CN 100359578C CN B2005101096356 A CNB2005101096356 A CN B2005101096356A CN 200510109635 A CN200510109635 A CN 200510109635A CN 100359578 C CN100359578 C CN 100359578C
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Abstract
A convex portion is provided on the objective side of a solid immersion lens so as to protrude toward an optical recording medium and a difference-in-level portion or a concave portion is provided at least on a part of this convex portion. Then, there are provided a solid immersion lens for satisfactorily holding the bonding state of a lens holding member, a focusing lens using this solid immersion lens, an optical pickup apparatus, an optical recording and reproducing apparatus and a method of forming a solid immersion lens.
Description
The cross reference of related application
The present invention comprises the relevant theme of submitting in Jap.P. office in the Japanese patent application JP2004-267397 of Jap.P. office submission, on February 22nd, 2005 with on September 14th, 2004 of Japanese patent application JP2005-045736, and its full content is incorporated into herein as a reference.
Technical field
The method that the present invention relates generally to a kind of solid immersion lens (SIL), the condenser lens that uses solid immersion lens, optical take-up apparatus, optics (or optomagnetic) record and regeneration (reproducing) device and form solid immersion lens.More specifically, the present invention relates to a kind of relation record of so-called near field and regenerative system of being suitable for, wherein by using optical lens to have the numerical aperture that big refractive index materials improves condenser lens, record the information in thus on optics (or the light-magnetic) recording medium and from its regeneration, and use condenser lens, the optical recording of this solid immersion lens and install and form the method for solid immersion lens again.
Background technology
With compact disk (CD), mini-disk (MD) and digital universal disc (DVD) is the optical record medium (comprising Magnetooptic recording medium) of representative, is widely used in storing therein the storage matrix of music information, video information, data, program etc.Yet, along with music information, video information, data, program etc. are improved day by day, and become longer, memory capacity of become on tune quality, picture quality higher, writing time and playing time becomes bigger, this requires optical record medium should improve on storage volume, and should realize writing down and regenerating this optical recording and regenerating unit (comprising magneto-optical recorder and regenerating unit) of optical record mediums of storage in a large number.
Therefore, in order to satisfy above-mentioned requirements, in optical recording and regenerating unit, it is the wavelength decreases of the light source of semiconductor laser for example, and the numerical aperture of condenser lens improves, and the diameter of the light beam spot that converges by condenser lens reduces thus.
For example, with regard to semiconductor laser, the GaN semiconductor laser comes into operation, and the wavelength of its emitted laser is reduced to the 400nm band from the 635nm of the red laser of correlation technique, has therefore reduced the diameter of light beam spot.And, about being reduced to wavelength greater than above-mentioned short wavelength, for example can launch the extreme ultraviolet solid-state laser of single wavelength laser of 266nm continuously, on market, can commercially obtain (to produce now by S0ny company, the trade mark is UW-1020), so can further reduce spot diameter.In addition, researching and developing now secondaries laser instrument (266nm band), the adamas laser instrument (235nm band) of Nd:YAG, the secondaries laser instrument (202nm band) of GaN laser instrument etc.
After deliberation so-called near-field optical recording and regenerative system, wherein by using by the optical lens with big digital aperture of solid immersion lens (SIL) as representative, can realize having digital aperture greater than 1 condenser lens, and the objective lens surface of wherein utilizing this condenser lens is near optical record medium, distance is about 10/1 of its optical source wavelength, can write down and regenerate (for example referring to quoting patent reference as proof, US Patent No.5125750).
In this near-field optical recording and regenerative system, importantly in the distance that remains under the high-precision optical contact condition between optical record medium and the condenser lens.And, because enter into the beam diameter of condenser lens reduces from light source, and the distance between optical record medium and condenser lens reduces and becomes very little, it is less than about tens nanometers, be that so-called degree of tilt between optical record medium and condenser lens can become very little, so condenser lens inevitably is subjected to the very big restriction of fixed in shape point (shape standpoint).
When the condenser lens with above-mentioned layout was applied to optical recording and regenerating unit, for example it was installed in and has two-axis adjuster and thus the distance between optical record medium and the condenser lens is remained on the optics contact condition.When above-mentioned condenser lens was applied to magneto-optical recorder, the magnetic head assembly that will be used for magnetic recording and regeneration was assembled in optical take-up apparatus, similarly the distance between optical record medium and the condenser lens can be remained on the optics contact condition thus.
In above-mentioned near-field optical recording and regenerative system, be controlled at respect to the focus direction of optical record medium and/or seek the condenser lens that drives on rail (tracking) direction for stable, also in order stably to write down and the optical record medium of regenerating, must between the objective lens surface of optical record medium and condenser lens, keep a certain amount of degree of tilt simultaneously.
Therefore, the application's assignee has proposed solid immersion lens before, it is open in U.S. Patent application No.11/063608, for example wherein on the object lens side of immersion lens, form jut as circular vertebra shape jut or pyramid shape jut, and its end portion is processed into planar section so that objective lens surface to be provided, therefore, even when the distance between objective lens surface and the optical record medium is chosen to about tens nanometers, also can keep the degree of tilt of ± 0.1 degree approximately.Therefore, can provide stable optical recording of optical take-up apparatus and record and reproducing characteristic and regenerating unit.
In the solid immersion lens that on object lens side as mentioned above, forms with jut, increase along with the digital aperture NA of solid immersion lens, the incident angle that is laser increases, and the protrusion angles of jut should reduce, so that do not influence the input path of laser.For example, when solid immersion lens be shaped as the circular cone solid immersion lens time, should improve the angle of cone apex angle.
As a result, the bond area of solid immersion lens with lens keeper of the solid immersion lens that is used to keep to have big digital aperture NA reduces, and under the situation that applies very little vibrations, produces the danger that lens keeper and solid immersion lens separate.
Equally, along with the reduction of the spherical part radius of solid immersion lens or along with the increase of solid immersion lens refractive index, the bond area with solid immersion lens of the lens keeper that is used to keep this solid immersion lens reduces.And above-mentioned bond area is equally along with in the increase of optically focused planar section (the being objective lens surface) radius on jut top and reduce.
Particularly, in order to satisfy the requirement of making high-density optical record medium and manufacturing dimension compactness and lightweight optical take-up apparatus in the future, should increase the digital aperture of solid immersion lens and make the solid immersion lens microminiaturization.So, even when the bond area of the solid immersion lens that can reduce to have the lens keeper that is used to keep this solid immersion lens greatly, solid immersion lens also can be fixed with being stabilized and be kept.
Summary of the invention
In view of above-mentioned aspect, the present invention attempts to provide a kind of be used for keeping the satisfactorily solid immersion lens of bond state, the condenser lens, optical take-up apparatus, optical recording and the regenerating unit that use this solid immersion lens and the formation method of solid immersion lens between solid immersion lens and lens keeper.
According to a scheme of the present invention, a kind of solid immersion lens is provided, it is included in the jut that is provided with on the object lens side of solid immersion lens and the level difference that is provided with at least part or sunk part on the part jut.
According to another aspect of the present invention, provide a kind of condenser lens, it comprises solid immersion lens; The optical lens that its optical axis is consistent with solid immersion lens, it is positioned at the opposition side of object lens side; The jut that on the object lens side of solid immersion lens, is provided with highlightedly and the level difference that on the part jut, is provided with at least part or sunk part.
According to another aspect of the present invention, provide a kind of optical take-up apparatus, which comprises at least solid immersion lens; The optical lens that its optical axis is consistent with light source, they are located successively from the object lens side; Be used to assemble light by light emitted to form the condenser lens of light beam spot; On the object lens side of solid immersion lens, be provided with the jut of giving prominence to optical record medium and the level difference that on the part jut, is provided with at least part or sunk part.
According to further scheme of the present invention, a kind of optical recording and regenerating unit are provided, which comprises at least optical take-up apparatus, be used for light being concentrated on the record position of optical record medium, with record and/or regeneration optical record medium by condenser lens; And accessory drive, be used for seeking rail direction mobile focusing lens and optical take-up apparatus at focus direction and/or optical record medium, focalizer comprises the condenser lens of the solid immersion lens that is positioned at the object lens side at least, and jut is arranged on the object lens side of solid immersion lens has level difference part or the sunk part that is provided with at least with and jut outstanding to optical record medium on its part.
Still according to further scheme of the present invention, a kind of formation method of solid immersion lens is provided, comprises the steps: on the object lens side of solid immersion lens, to form jut and on the part outshot, form level difference part or sunk part at least by the focused ion beam disposal route.
As mentioned above, according to solid immersion lens of the present invention, because outstanding jut is arranged on the object lens side of solid immersion lens, the jut of level difference part or sunk part is arranged on the part outshot at least, can improve bonded areas with the lens keeper, so compare with correlation technique, the scioptics keeper can more stably keep solid immersion lens.
And, according to condenser lens of the present invention, optical take-up apparatus and optical recording and regenerating unit, can stably keep the solid immersion lens that uses with condenser lens, have the solid immersion lens of big digital aperture by use, can provide can be with respect to optical take-up apparatus and the optical recording and the regenerating unit of optical record medium stable motion.
And, according to the formation method of solid immersion lens of the present invention, under the situation of incident light not being exerted one's influence, can form accurately and can be compared the solid immersion lens that stably keeps.
Description of drawings
Fig. 1 illustrates the synoptic diagram of use according to the layout of the condenser lens example of the solid immersion lens (SIL) of prior art;
Fig. 2 is the synoptic diagram that illustrates according to the layout of condenser lens example of the present invention;
Fig. 3 illustrates the synoptic diagram of arranging according to the major part of optical take-up apparatus example of the present invention;
Fig. 4 illustrates the synoptic diagram of arranging according to the major part of optical recording of the present invention and regenerating unit example;
Fig. 5 A illustrates the schematic side view that can be applied to solid immersion lens example of the present invention;
Fig. 5 B illustrates the floor map that can be applied to solid immersion lens example of the present invention;
Fig. 6 A illustrates the schematic side view that can be applied to another example of solid immersion lens of the present invention;
Fig. 6 B illustrates the floor map that can be applied to another example of solid immersion lens of the present invention;
Fig. 7 A illustrates the schematic side view that can be applied to the further example of solid immersion lens of the present invention;
Fig. 7 B illustrates the floor map that can be applied to the further example of solid immersion lens of the present invention;
Fig. 8 A remains the schematic side view that can be applied to another example of solid immersion lens of the present invention is shown;
Fig. 8 B remains the floor map that can be applied to another example of solid immersion lens of the present invention is shown;
Fig. 9 is the schematic side view that solid immersion lens is shown;
Figure 10 is the synoptic diagram that the solid immersion lens example arrangement states that keeps by keeper is shown;
Figure 11 is the synoptic diagram that the solid immersion lens example arrangement states that keeps by keeper is shown;
Figure 12 illustrates the cross sectional representation of arranging according to solid immersion lens example of the present invention;
Figure 13 illustrates the cross sectional representation of arranging according to another example of solid immersion lens of the present invention;
Figure 14 illustrates the cross sectional representation that the further example of solid immersion lens according to the present invention is arranged;
Figure 15 remains the cross sectional representation that the further example of solid immersion lens according to the present invention is arranged is shown;
Figure 16 still illustrates the cross sectional representation that the further example of solid immersion lens according to the present invention is arranged;
Figure 17 is a reference view of explaining the shape of solid immersion lens example; And
Figure 18 is a reference view of explaining the shape of another example of solid immersion lens.
Embodiment
Although describe embodiments of the invention below with reference to accompanying drawing, need not superfluous words, the invention is not restricted to the following examples.
The present invention can be applied to the condenser lens that is made of solid immersion lens and optical lens, and wherein optical lens has the optical axis consistent with solid immersion lens, and it is positioned at the opposite of object lens side.And the present invention can be applied to comprise the optical take-up apparatus of this condenser lens, optical recording and regenerating unit that it uses so-called near-field optical recording and regenerative system and comprises this optical take-up apparatus.
Before describing, will the embodiment that wherein applies the present invention to condenser lens, optical take-up apparatus and optical recording and regenerating unit be described with reference to figs. 2 to 4 according to solid immersion lens of the present invention.In Fig. 2 to 4,, provide the shape of solid immersion lens by simplifying the example of arranging according to the present invention in order to help to illustrate the layout and the setting of solid immersion lens.Much less, the shape of this solid immersion lens can adopt layout of the present invention, comprises that Fig. 5 A and 5B reach the example of following accompanying drawing.
Fig. 2 is the synoptic diagram that illustrates according to the layout of condenser lens example of the present invention.As shown in Figure 2, the solid immersion lens of arranging according to the present invention 11 and optical lens 12 with this order by this way with the lens target for example optical record medium become the opposed relationship setting.Thereby their optical axis is consistent each other.The semisphere that being shaped as of solid immersion lens 11 has radius-of-curvature r or spherical mostly.When solid immersion lens forms semisphere, will be chosen as r along its its thickness of optical axis extending.When solid immersion lens 11 forms semisphere as the example among the figure,, be chosen as r (1+1/n) along its thickness of optical axis extending if refractive index is chosen as n.Arrange according to this, the condenser lens 13 that has above the digital aperture of the digital aperture NA of optical lens 12 can be provided.
Though solid immersion lens 11 does not contact each other with optical record medium 10 in actual applications, but it is enough little that the interval between solid immersion lens 11 and optical record medium 10 is compared with the thickness of solid immersion lens 11, to such an extent as to so little interval is not shown in Fig. 2 to 4.Distance between solid immersion lens 11 and the optical record medium 10 is shorter than the Wavelength of Laser from light emitted.Particularly, when optical maser wavelength was 405nm, the distance between solid immersion lens 11 and the optical record medium 10 was in very close each other state, and distance is 85nm or 25nm.
Fig. 3 be illustrate use solid immersion lens shown in Figure 2 and condenser lens the synoptic diagram of layout example of optical system of optical take-up apparatus.For example, although first and second beam splitters 14 and 15 not shown, and constitute condenser lens 13 by solid immersion lens 11 and optical lens 12 between light source and photo-detector.For example, if it is shaped as dish type, optical record medium 10 is installed on the spindle motor (not shown), and rotates with desired speed.
And the optical take-up apparatus shown in Fig. 2 and 3 has the parts that are used for seeking rail direction and focus direction mobile focusing lens 13.
As these parts, can be enumerate pick up the two-axis adjuster of using with normal optical, the slider that uses with magnetic head assembly.
These controlling and driving examples of members of using together with condenser lens 13 will be described below.
Fig. 4 is the synoptic diagram of layout that the optical take-up apparatus example of a part of optical recording of formation according to the present invention and regenerating unit is shown, and promptly uses the example of two-axis adjuster as the optical take-up apparatus of controlling and driving parts.As shown in Figure 4, by lens keeper 20 fixed focus lenses 13, the optical axis of solid immersion lens 11 and optical lens 12 can be consistent each other thus.This lens keeper 20 is fixed to and can and/or seeks the two-axis adjuster 16 that the rail direction drives in focus direction.
As shown in Figure 4, two-axis adjuster 16 is made of with the focusing coil 18 that is used at focus direction driving condenser lens 13 the path circle 17 of seeking that is used for seeking rail direction driving condenser lens 13.
Then, for example by monitoring the quantity of back light, this two-axis adjuster 16 can be controlled the distance between optical record medium 10 and the solid immersion lens 11, can feed back the range information of gained thus.As a result, the distance between optical record medium 10 and the solid immersion lens 11 can keep substantial constant, and can stop solid immersion lens 11 and optical record medium 10 to collide each other.
And, by monitoring that this two-axis adjuster 16 can move to required track with the focused beam acts point, can feed back the positional information of gained thus in the quantity of seeking back light on the rail direction.
Refer back to Fig. 3 again, will describe the illustrative arrangement of optical take-up apparatus below.As shown in Figure 3, to become directional light (L1) from outside optical alignment by the collimation lens (not shown), through first beam splitter 14 (L) and converge to by condenser lens 13 on the information recording surface of optical record medium 10 as the light emitted of semiconductor laser.Inside light process condenser lens 13 in the information recording surface reflection also enters second beam splitter 15 thus by the reflection of first beam splitter 14 (L2).Then, the inside light (L3 and L4) that is separated by second beam splitter 15 focuses on focused light detector (not shown) and the flashlight detector (not shown), and detects the rub-out signal that focuses on, the pit signal of regeneration etc. thus.
And, for example, focus on by the inside light of second beam splitter 15 reflection and to seek the rail photo-detector, and detect thus and seek the rail rub-out signal.If necessary, in this optical take-up apparatus, in order to eliminate rotation fluctuation from the dish of optical record medium 10, can proofread and correct the focusing error component and by change two between the lens the interval and the relay lens of the error component that in the assembling process of condenser lens, forms can be inserted between first beam splitter 14 and the optical lens 12, wherein, condenser lens 13 two-axis adjuster 16 fixed thereon can not exclusively be followed (follow) described focusing error component.
Although it is not shown, when condenser lens is installed on the slider, parts as the error component that is used to proofread and correct all the other focusing error components of following slider and produces at the assembling process of condenser lens, condenser lens can be fixed to slider, by the suitable components of for example piezoelectric element, optical lens can move on optical axis direction.
And in the situation of optical recording and regeneration, wherein spindle motor comprises the parts that a plurality of optical record mediums are installed, and slider can comprise that the mirror that is used for basic crooked 90 degree of optical axis is suitable.Can reduce interval between the optical record medium because have the optical recording of above-mentioned layout and regenerating unit, institute is the little and thin thickness of size so that device can become.
Above-mentioned optical take-up apparatus only can comprise for regenerating information separately design the reproduced light pick device, only for recorded information separately design the recording light pick device and be the record and the reproduced light pick device of record and regenerating information design.Can revise above-mentioned optical take-up apparatus separately, make magnetic coil etc. to be assembled into the part optical take-up apparatus.This optics also will be used for thermo magnetic recording and regenerative system.And, optical recording and regenerating unit only can comprise for regenerating information separately design regenerating unit, only be the recorded information pen recorder of design and the record and the regenerating unit that can write down and regenerate separately.
Next the example that is suitable for the lens shape of solid immersion lens according to of the present invention will be described.
Fig. 5 A and 5B are schematic side view and the floor map that illustrates according to solid immersion lens example of the present invention.In this example, head 1 be shaped as hemispherical portion, and have solid immersion lens 11, wherein radius-of-curvature is assumed to be r, refractive index is assumed to be n, the thickness that extends along the direction of optical axis c is assumed to be r (1+1/n).The jut 2 outstanding towards optical record medium is arranged on the object lens side.
In Fig. 5 A and 5B, dotted line R represents xsect, and wherein radius is r on xsect, and this xsect is perpendicular to the optical axis of solid immersion lens 11.
In this solid immersion lens 11, the shape of jut 2 can be tapered segment or pyramid part.
In addition, shown in Fig. 6 A and 6B, the shape of head 1 can be chosen as the hemispherical portion of r for its thickness, and the shape of jut is essentially circular cone or pyramid part.Like this, can form the shape that is restricted to ball basically in the objective lens surface 3 of head portion, shown in dotted line f, its radius is essentially r/2.In this case, has following advantage, promptly even when the optical axis of the optical axis of the incident light of for example laser and solid immersion lens 11 tilts a little, can prevent that also incident light wherein from changing through the distance of solid immersion lens 11, so incident light concentrates on the objective lens surface satisfactorily.
And, shown in Fig. 7 A and 7B, the shape of head 1 can be hemispherical portion, the shape of jut 2 is essentially taper shape or pyramid, objective lens surface 3 at head portion can form the shape that is restricted to ball basically, shown in dot-and-dash line line g, for example, its radius is gathered in r/n.Equally in this case, has following advantage, promptly even when the optical axis of the optical axis of the incident light of for example laser and solid immersion lens 11 tilts a little, can prevent that also wherein the distance of incident light process solid immersion lens 11 changes, so incident light concentrates on the objective lens surface satisfactorily.
And shown in Fig. 8 A and 8B, for example, jut 2 can form the various curved surfaces that comprise spherical surface.
In Fig. 6 A and 6B, Fig. 7 A and 7B and Fig. 8 A and 8B, represent and Fig. 5 A and same element and the part of 5B by same reference number, therefore need not to describe.
The pitch angle of jut 2 is set at greater than incident angle, so that do not influence incident light from laser.When the lens material that uses refractive index in about scope of 2 to 3, it with the angle of objective lens surface 3 basically in the scopes of 10 to 30 degree.
And, because near-field optical recording relevant with optical record medium and regenerative system need magnetic field when record and/or regeneration, so on the part of the objective lens surface 3 of solid immersion lens 11 or around objective lens surface 3 additional suitable device, for example magnetic coils of solid immersion lens 11.
As the material of this solid immersion lens 11, as mentioned above, can use the material that has big refractive index, big transmissivity and little absorptivity with respect to the wavelength of the lasing light emitter of optical recording and regenerating unit and optical take-up apparatus suitably.For example, by the S-LAH79 (trade mark) that OHARA company produces, it is a glass of high refractive index, Bi
4Ge
3O
12, SrTiO
3, ZrO
2, HfO
2, SiC, KtaO
3, adamas, these high index ceramic or high index of refraction monocrystal material also can be suitable materials.
And, need these materials should have non crystalline structure, if they are monocrystal materials, need them should have cubic structure.If lens material has non crystalline structure or cubic structure, so because do not change etch-rate or etching characteristic, so obtained being used to handle known semi-conductive engraving method and etch system by the angle, grain arrangement.
Then, in solid immersion lens according to the present invention, level difference (difference-in-level) part or sunk part are arranged on to the small part jut.
When handling this level difference part or sunk part, if the level difference part is by constituting more than two inclined surfaces, its have sunk part the degree of depth or along in the xsect of the optical axis extending of solid immersion lens with respect to the different pitch angle of optical axis.The caustic solution that is used for semiconductor processes and the etching system at the pitch angle of high Precision Processing dip plane have been obtained being used for.Particularly, when handling the pitch angle of very little sloping portion or depression and shape for lugs, preferably by use the focused ion beam disposal methods they, this method is based on the focused ion beam disposal system, for example the focused ion beam check system FB-2100 (trade mark) that makes of HITACCHI company.When forming inclined surface, curved surface etc. by the focused ion beam disposal route, have and can high precision regulate pitch angle etc. and can reliable treatments level difference part under the situation that does not influence incident light or the advantage of sunk part.
Then, before describing the effect that obtains by level difference part and sunk part, the mode that solid immersion lens and keeper bond together is described with reference to the drawings earlier according to solid immersion lens of the present invention.
Fig. 9 is the cross-sectional view that the amplification that the major part of example of the solid immersion lens 11 of the jut 2 with head 1 and circular vertebra shape or pyramid shape arranges is shown.As shown in Figure 9, in this example, head 1 be shaped as hemispherical portion, wherein its radius-of-curvature is assumed to be r, be assumed to be θ along the angle along the plane (b represents by dotted line) of objective lens surface 3 in the optical axis c xsect of jut 2, the radius of objective lens surface 3 is assumed to be d, the thickness of solid immersion lens 11 is assumed to be r (1+1/n), height from the objective lens surface 3 of jut 2 to the marginal portion 4 of head 1 is assumed to be x, 4 distance is assumed to be y from the optical axis to the marginal portion, and the refractive index of the wavelength that has in the solid immersion lens 11 is assumed to be n.In Fig. 9, dotted line a represents to pass the xsect of the marginal portion 4 of head 1, and it is the xsect of r that dotted line R is illustrated in perpendicular to radius in the xsect of optical axis c.
At this moment, calculate from objective lens surface 3 to head 1 tiltangle and the relation the height x from following equation (1) and (2):
tanθ＝x/(y-d) ……(1)
r
2＝y
2+((r/n)-x)
2 ……(2)
For example, when radius r was chosen as 0.45mm, the radius d of objective lens surface 3 was chosen as 20 μ m, and the refractive index n of lens is chosen as 2.075, spend when in 30 degree scopes, changing 10 when tiltangle, calculate from objective lens surface 3 to head the height of 1 marginal portion 4, i.e. difference in height x.
The lens keeper is bonded on the lens by this way, i.e. its surface (with the optical record medium facing surfaces) surplus certain at interval with objective lens surface 3.In this surplus, when the difference in height on lens keeper and lens objectives surface is 50 μ m, the value of the height of the bonded areas between lens keeper and lens (difference in height) x ' deducts 50 μ m by above-mentioned difference in height x and produces, and the length y ' of the bonded areas in xsect shown in Figure 9 is obtained by y '=x '/(sin θ).List the result in the table 1 below.
Table 1
| Tiltangle (degree) | Difference in height x (μ m) from the objective lens surface of marginal portion | The difference in height x ' of bonded areas (μ m) | The length y ' of bonded areas (μ m) |
| 10 | 71.6 | 21.6 | 124.4 |
| 15 | 111.9 | 61.9 | 239.1 |
| 20 | 155 | 105 | 307 |
| 25 | 200.4 | 150.4 | 355.9 |
| 30 | 247.7 | 197.7 | 395.4 |
Very clear from the result of table 1, when the tiltangle of jut 2 is 30 when spending, can keep 1 the difference in height of 250 μ m nearly from objective lens surface 3 to head.Yet, when tiltangle is 30 when spending, can keep the difference in height of 1 marginal portion 4 of 70 μ m nearly at most from objective lens surface 3 to head.Studies show that the difference in height x of 1 marginal portion 4 is with the reducing and reduce of tiltangle from objective lens surface 3 to head, and the difference in height x ' of bonded areas and length y ' reduce also.
In solid immersion lens, along with the increase of digital aperture NA, i.e. the increase at laser pitch angle, or along with the radius r of solid immersion lens reduce and along with the reducing of refractive index n, the tiltangle of jut 2 reduces.Therefore clearly, along with the increase of the digital aperture NA of solid immersion lens, the height of 1 marginal portion 4 reduces from objective lens surface 3 to head, and has reduced the size and the weight of solid immersion lens.
Figure 10 and 11 is illustrative arrangement that each example of solid immersion lens is shown, in solid immersion lens with above-mentioned jut 2, the part inclined surface of jut 2 is used as the bonded areas 5 of lens keeper 20, cementing agent 6 by the material that is fit to of for example ultraviolet-curing resin or thermosetting resin is made fixedly is bonded to bonded areas 5 with lens keeper 20.When the plane is seen, lens keeper 20 be shaped as annular ring with circular hole around objective lens surface 3.The shape of cross section of lens keeper 20 on optical axis is triangle, wherein forms acute angle towards objective lens surface 3.
Because at the radius of the objective lens surface 3 of the end of the jut 2 of solid immersion lens 11 in about several microns to tens microns scope, the pitch angle of jut 2, promptly the angle θ that forms with respect to objective lens surface 3 spends in the scopes of 30 degree about 10, the height x between the surface of objective lens surface 3 and the lens keeper 20 relative with the optical record medium (not shown) about tens microns in the scope of hundreds of micron.
Figure 10 illustrates the examples that angle θ wherein is about 20 degree, and Figure 11 illustrates wherein that angle θ is the examples of about 10 degree.In Figure 10 and 11, represent and Fig. 9 components identical and part by identical reference number, therefore do not need to describe.
Result of study to above-mentioned table 1 and Figure 10 and 11 shows, along with reducing of the tiltangle of jut 2, bonded areas reduces.
Particularly, as shown in figure 10, when tiltangle relatively became big, 4 difference in height x became greatly head 1 relatively to the marginal portion by objective lens surface 3, and can keep bonded areas 5.On the other hand, as shown in figure 11, when tiltangle diminished relatively, 4 difference in height x's head 1 relatively diminished to the marginal portion by objective lens surface 3.As a result, be appreciated that with the example of Figure 10 and compare that the area of bonded areas 5 obviously reduces.
And, shown in the example of Figure 11, when the tiltangle of jut 2 diminishes, when difference in height between the surface of objective lens surface 3 and the lens keeper 20 relative with optical record medium diminishes, the interval between lens keeper 20 and the optical record medium also reduces.Like this, in order to keep the pitch angle between a certain amount of optical record medium and the lens keeper 20, the size that should suppress lens keeper 20 increases, so bonded areas reduces manyly.
For example, as mentioned above, when the difference in height between the surface of the objective lens surface 3 of solid immersion lens and the lens keeper 20 relative with optical record medium is chosen as 50 μ m, shown in above-mentioned table 1, if tiltangle be 30 the degree, can keep about 400 μ m bonded areas length y ' so yet, if tiltangle be 10 the degree, be appreciated that the difference in height x ' that only can keep 20 μ m and the length y ' of about 120 μ m so.
As mentioned above, very little when regional when lens keeper 20 is bonded as, because bonded areas diminishes, so lens keeper 20 is bonded to little bonded areas inevitably, this is very unstable in actual applications.
In order to address this problem,, on the part jut, form level difference part or sunk part at least according to the present invention.
At first, referring to figs. 12 to 15 the example that wherein forms sunk part on the bonded areas of the jut of being with keeper is described.
Figure 12 shows an example, wherein jut 2 be shaped as tapered segment, for example on the bonded areas 5 of the taper inclined surface of lens keeper 20, form sunk part 7 with triangular cross section.When on bonded areas 5 as mentioned above, forming sunk part 7, increase bonded areas by on bonded areas 5, forming very little uneven surface with cementing agent 6, therefore compared with prior art, solid immersion lens 11 enough can be firmly held on the lens keeper 20.
When handling sunk part 7, preferably handle sunk part 7 by the focused ion beam method, this method is based on the focused ion beam disposal system, and for example the focused ion beam of being made by HITACHI company is handled detection system FB-2100 (trade mark).When forming sunk part 7 by focused ion beam disposal route as mentioned above, can form the shape of sunk part 7 accurately, its degree of depth for example, and can avoid influencing the incident light of representing by dotted arrow Li that enters in the solid immersion lens 11.In Figure 12, represent element and the part same by same reference number with Fig. 9, therefore need not to describe.
Figure 13 represents an example, wherein sunk part 7 is shaped to have square xsect.Equally, by sunk part 7 is provided, can increase the bonded areas in the bonded areas 5 equally, and solid immersion lens 11 fixedly can be bonded to keeper with enough big intensity.
In Figure 12, represent element and the part same by same reference number with Fig. 9, therefore need not to describe.
As mentioned above, when jut 2 be shaped as circular cone, pyramid and curved surface any the time, a kind of solid immersion lens that can maintain can be provided with being stabilized, wherein, just can remain on bonded areas in this solid immersion lens by simple relatively shape.
The shape of solid immersion lens 11 is not limited to Figure 12 and 13 shown those examples, head can be configured as hemispherical part.And as shown in Figure 4, for example, the shape of solid immersion lens 11 can be identical with the above-mentioned example of Fig. 7, wherein objective lens surface 3 formed such shape, promptly limits a sphere basically, and shown in dot-and-dash line g, radius is r/n, for example as shown in figure 14.And, as shown in figure 15, jut 2 can be formed curve form, promptly jut 2 can be formed above-mentioned example similar shapes with Fig. 8.As mentioned above, shown in Figure 14 and 15, when on bonded areas 5 sunk part 7 being set, it becomes and solid immersion lens 11 fixedly can be bonded to lens keeper 20, and has enough big intensity.In Figure 14 and 15, represent element and the part same by same reference number with Figure 12, therefore need not to describe.
As mentioned above, when on part bonded areas 5, forming sunk part 7 at least, relatively will be clear with the above-mentioned example of Figure 11, the amount by the non-uniform areas of processing in the sunk part 7 of jut 2 can increase bond area.So, owing to can stably keep solid immersion lens, even when the size of solid immersion lens is done compactly, also can stably keep solid immersion lens, therefore can make the relative motion of solid immersion lens and optical record medium etc. stable.
Particularly, when the tiltangle of jut 2 is done relatively hour, promptly when laser incident angle θ i increase of arriving solid immersion lens 11 and digital aperture NA increase, or when the refractive index n of solid immersion lens 11 becomes big, and then when the radius r of solid immersion lens 11 diminishes,, can keep bonded areas by above-mentioned sunk part is provided, by this bonded areas, solid immersion lens 11 stably can be remained on the lens keeper 20.
Next the example that wherein forms the level difference part on the part jut will be described.In the example shown in Figure 16, the level difference part 8 that forms on jut 2 is made of plural inclined surface, this inclined surface is oblique with different angle lappings with respect to the optical axis c in the xsect that extends at the optical axis c along solid immersion lens 11, i.e. first surface 9A and the second surface 9B that forms successively from objective lens surface 3 in an example shown.
As mentioned above, if the sloping portion of jut 2 is processed into respect to optical axis with different angle tilts, the part that promptly has a plurality of pitch angle, even increase when increasing the digital aperture of solid immersion lens 11 from optical axis when the pitch angle of jut 2, by inclined surface is provided, wherein the pitch angle from optical axis reduces with respect to lens keeper 20 in bonded areas 5, like this, second surface 9B, it in this inclined surface, can increase bonded areas relatively, so can remain to solid immersion lens 11 on the lens keeper 20 with respect to lens keeper 20.
Yet in this case, need to consider that incident angle θ i selects the pitch angle of second surface 9B, so that do not interfere with the incident light Li of solid immersion lens 11.
Particularly, by the radius d of objective lens surface 3, the pitch angle of the jut 2 of solid immersion lens 11 can be formed with the surplus with respect to the incident angle θ i that arrives solid immersion lens 11.In other words, by using this surplus, can provide its from the pitch angle of objective lens surface 3 the second surface 9B greater than the pitch angle of first surface 9A.As a result, the length of raising sloping portion that can be bigger can be kept the bond area with respect to lens keeper 20 thus.
Equally in this case, when the pitch angle of jut became relative hour, when the incident angle of the incident light when at solid immersion lens becomes big, when digital aperture NA becomes big, when the refractive index of solid immersion lens is big or when the radius of solid immersion lens hour, can keep stable bonded areas.
In Figure 16, represent element and the part same by same reference number with Figure 12, therefore need not to describe.
Next the example that wherein forms sunk part or level difference part under the situation that does not influence incident light will be described, as example 1 and 2.
(1) example 1:
As solid immersion lens, use is also arranged by synoptic diagram shown in Figure 17 by the glass of high refractive index material S-LAH79 (trade mark) that OHARA company makes, produce the solid immersion lens of example 1 like this, wherein the radius r of solid immersion lens 11 is chosen as 0.45mm, its thickness r (1+1/n) is chosen as 0.667mm, at the circular cones that have 20 degree pitch angle with respect to objective lens surface 3 that are shaped as of the jut 2 of object lens side.At this moment, the radius d of objective lens surface 3 is chosen as 20 μ m.
In this example 1, when head 1 when 4 height x is 155.0 μ m to the marginal portion from objective lens surface 3, the height Xi of the incoming position from objective lens surface 3 to incident light Li is 216.6 μ m.Therefore, according to the processing based on focused ion beam system, the height x by cutting 61.6 μ m and the part of the difference between the xi form the very little sunk part shown in Figure 12, and sunk part are bonded to the lens keeper 20 of solid immersion lens 11.As a result, as shown in figure 10, and do not compare by the situation that forms sunk part according to the cutting of machining, it is proved to be has improved cohesive strength.
(2) example 2:
Next example 2 is described.As solid immersion lens, the glass of high refractive index material S-LAH79 (trade mark) that use is made by OHARA company and as shown in figure 18, produce the solid immersion lens of example 2 like this, wherein the radius r of solid immersion lens 11 is chosen as 0.45mm, its thickness r (1+1/n) is chosen as 0.667mm, at the circular cones that have 10 degree pitch angle with respect to objective lens surface 3 that are shaped as of the jut 2 of object lens side.At this moment, the radius d of objective lens surface 3 is chosen as 20 μ m.
At this moment, when head 1 when 4 height x is 71.6 μ m to the marginal portion from objective lens surface 3, the height Xi of the incoming position from objective lens surface 3 to incident light Li is 130 μ m.Therefore, according to focused ion beam system, the height x by handling 58.4 μ m and the part of the difference between the xi form the level difference shape shown in Figure 16, and this level difference partly are bonded to the lens keeper 20 of solid immersion lens 11.As a result, compare with the situation that does not form this level difference part, it is proved to be has improved cohesive strength.
Incident angle θ i, the tiltangle of example 1 and 2, height x and the height x of incoming position and poor (xi-x) between the height xi of marginal portion have been listed in the table 2 below.
Table 2
| Incident angle θ i (degree) | Tiltangle (degree) | Height x (μ m) from objective lens surface to the marginal portion | Poor (μ m) between X and the Xi | |
| Example 1 | 64.3 | 20 | 155 | 61.6 |
| Example 2 | 73.6 | 10 | 71.6 | 58.4 |
As mentioned above, height xi by considering incoming position and from the objective lens surface to the rims of the lens part difference in height x and suitably be chosen in the degree of depth of the sunk part that forms on the bonded areas, can keep bonded areas and not disturb incident light, therefore solid immersion lens can be bonded on the lens keeper securely.
As mentioned above, according to solid immersion lens of the present invention,, jut can improve tilt margins with respect to optical record medium by being provided.And, by to the small part projection, forming sunk part or level difference part, between solid immersion lens and lens keeper, can keep enough big bonded areas.
Then, according to the present invention, can stably keep little solid immersion lens, it can realize having the condenser lens of big digital aperture.Therefore, can realize that the solid condenser lens moves with respect to the stable of optical record medium, so it can improve the stability of record and regeneration.Like this, can construct record and the regenerative system stable that uses near-field recording and regenerative system with respect to optical record medium.
And, because can realize little lightweight condenser lens according to solid immersion lens of the present invention, can improve servo characteristic, for example focus servo, rail searching servo and search time by using.So, it optical recording and regenerating unit are become size is little, thin thickness, performance height.
As a result, according to the present invention,, can realize having more high record density and the more optical record medium of large storage capacity by using near-field recording and regenerative system.
The invention is not restricted to above-mentioned indivedual example, under the situation that does not break away from layout of the present invention, by in jut, forming the shape of cross section of sunk part, for example corrugated, irregular or level difference shape, it can carry out various modifications and variations, and the curved surface that has different curvature radius thus can close on each other.In addition, need not superfluous words, the shape of the material of solid immersion lens, layout, lens keeper etc. also can modifications and variations.
As mentioned above, according to solid immersion lens of the present invention, because jut is arranged on the object lens side of solid immersion lens, level difference part or sunk part are arranged on to the small part jut, therefore can improve bonded areas with the lens keeper, so compared with prior art, the scioptics keeper can more stably keep solid immersion lens.
And, according to condenser lens of the present invention, optical take-up apparatus and optical recording and regenerating unit, can stably keep the solid immersion lens that uses with condenser lens, have the solid immersion lens of big digital aperture by use, can provide can be with respect to optical take-up apparatus and the optical recording and the regenerating unit of optical record medium stable motion.
And, according to the formation method of solid immersion lens of the present invention, under the situation of incident light not being exerted one's influence, can form the solid immersion lens that can be compared stable maintenance accurately.
Those skilled in the art will appreciate that according to designing requirement and other factors can carry out various modifications, combination, subgroup is closed and select, they all drop in the scope of additional claim and equivalent thereof.
Claims (9)
1. solid immersion lens comprises:
Be arranged on the jut on the object lens side of described solid immersion lens; With
Be arranged on level difference part or sunk part on a part of described jut;
Wherein, described sunk part is arranged on a part of bonded areas of the keeper that keeps described solid immersion lens at least.
2. according to the described solid immersion lens of claim 1, wherein, described level difference part is made of plural clinoplane, and described clinoplane tilts with different angles with respect to the optical axis of described solid immersion lens.
3. according to the described solid immersion lens of claim 1, wherein, described jut has focusing block in centre, and described level difference part or described sunk part are arranged on the position except that described focusing block.
4. condenser lens comprises:
Solid immersion lens;
Optical lens, its optical axis is consistent with described solid immersion lens, and this optical lens is positioned at the opposition side of object lens side;
Be arranged on the jut on the object lens side of described solid immersion lens highlightedly; And
At least be arranged on level difference part or sunk part on a part of described jut;
Wherein, described sunk part is arranged on a part of bonded areas of the keeper that keeps described solid immersion lens at least.
5. according to the described condenser lens of claim 4, wherein, described jut has focusing block in centre, and described level difference part or described sunk part are arranged on the position except that described focusing block.
6. optical take-up apparatus comprises:
Solid immersion lens and optical lens, the optical axis of this optical lens is consistent with light source, and this solid immersion lens and this optical lens sequentially are provided with from the object lens side;
Be used to assemble light by described light emitted to form the condenser lens of light beam spot;
Be arranged on the object lens side of described solid immersion lens with to the outstanding jut of optical record medium;
At least be arranged on level difference part or sunk part on a part of jut;
Be used to keep the keeper of described solid immersion lens, described sunk part is arranged on a part of bonded areas of described keeper at least; And
Regulator is used for focusing on and/or seeking mobile described solid immersion lens on the rail direction.
7. optical recording and regenerating unit comprise:
At least one optical take-up apparatus is used for by condenser lens light being concentrated on the record position of optical record medium, with the record and/or the described optical record medium of regenerating;
Be used to keep the keeper of described solid immersion lens, described sunk part is arranged on a part of bonded areas of described keeper at least;
Regulator is used for focusing on and/or seeking mobile described solid immersion lens on the rail direction;
Accessory drive, be used in the focus direction of described optical record medium and/or seek and move described condenser lens and described optical take-up apparatus on the rail direction, described condenser lens comprises the solid immersion lens that is positioned on the object lens side at least, and jut is arranged on the object lens side of described solid immersion lens has level difference part or the sunk part that is arranged at least on its part with and described jut outstanding to described optical record medium.
8. a method that forms solid immersion lens comprises the steps:
On the object lens side of described solid immersion lens, form jut; And
On the described outshot of a part, form level difference part or sunk part by the focused ion beam disposal route.
9. the formation method of described solid immersion lens according to Claim 8, wherein, described jut be shaped as any in taper shape, pyramid and the curved.
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| JP2004267397 | 2004-09-14 | ||
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| US10545309B2 (en) | 2014-09-26 | 2020-01-28 | Hamamatsu Photonics K.K. | Solid immersion lens holder and image acquisition device |
| DE102020111715A1 (en) * | 2020-04-29 | 2021-11-04 | Carl Zeiss Microscopy Gmbh | IMMERSION LENS AND PROCEDURE FOR IMMERSION MICROSCOPY |
| CN114646291A (en) * | 2020-12-17 | 2022-06-21 | 均豪精密工业股份有限公司 | Detection equipment and method for detecting fitting degree of objective lens |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000251340A (en) * | 1999-02-26 | 2000-09-14 | Yamaha Corp | Optical/magneto-optical head |
| US6594430B1 (en) * | 2000-05-11 | 2003-07-15 | Carnegie Mellon University | Solid immersion lenses for focusing collimated light in the near-field region |
| US6594086B1 (en) * | 2002-01-16 | 2003-07-15 | Optonics, Inc. (A Credence Company) | Bi-convex solid immersion lens |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000251340A (en) * | 1999-02-26 | 2000-09-14 | Yamaha Corp | Optical/magneto-optical head |
| US6594430B1 (en) * | 2000-05-11 | 2003-07-15 | Carnegie Mellon University | Solid immersion lenses for focusing collimated light in the near-field region |
| US6594086B1 (en) * | 2002-01-16 | 2003-07-15 | Optonics, Inc. (A Credence Company) | Bi-convex solid immersion lens |
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