CN100454412C - Optical pickup device - Google Patents
Optical pickup device Download PDFInfo
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- CN100454412C CN100454412C CNB2006101603497A CN200610160349A CN100454412C CN 100454412 C CN100454412 C CN 100454412C CN B2006101603497 A CNB2006101603497 A CN B2006101603497A CN 200610160349 A CN200610160349 A CN 200610160349A CN 100454412 C CN100454412 C CN 100454412C
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- laser
- compensating element
- spherical aberration
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Abstract
A wavefront of a laser light is adjusted using a phase correcting element. The phase correcting element includes an electrode layer, an electrode layer arranged facing the former electrode layer, orientation films arranged on a surface facing the electrode layers, and a liquid crystal layer filled between the orientation films. One of the two electrode layers is formed with an electrode pattern (ring shaped electrode) for providing a spherical aberration correcting effect to the laser light within a constant distance from a center of a beam incident diameter, and a continuous electrode is arranged on an outer side thereof. Occurrence of the aberration by a lens shift is effectively suppressed by omitting electrodes arranged slightly on an inner side of the conventional beam incident diameter.
Description
Technical field
The present invention relates to optical take-up apparatus, especially be suitable for the device that when suppressing spherical aberration, uses.
Background technology
In recent years, along with the densification of CD, and the object lens of employing high-NA.But,, then make laser produce aberration easily because of the thick error of substrate of CD etc. if use the object lens of high-NA.Therefore, under this situation, in optical take-up apparatus, need spherical aberration correction mechanism.
Open to disclose in the flat 10-269611 communique (patent documentation 1) the spy and use the example of liquid crystal panel as the spherical aberration correction element.In addition, the spy opens 2000-40249 communique (patent documentation 2) and spy and opens and disclose the example of use liquid crystal panel as astigmatism compensating element and broom shape (coma) aberration compensating element in the flat 10-289465 communique (patent documentation 3).
According to the invention of record in the patent documentation 1,, revise the corrugated state of laser, can suppress spherical aberration by the phase place correcting action of liquid crystal panel.But on the other hand, in case, the problem of aberration then can correspondingly occur producing in the laser because of the lens of object lens displacements (lens shift) or alignment error etc. produce optical axis deviation between liquid crystal panel and object lens.At this moment, in order between liquid crystal panel and object lens, not produce optical axis deviation, can adopt liquid crystal panel is installed on objective lens actuator, makes the structure of liquid crystal panel and object lens displacement integratedly.But, so, cause objective lens actuator to maximize, produce in addition the driving response and the kinetic characteristic of object lens are brought dysgenic problem.And, if produce the alignment error of liquid crystal panel with respect to objective lens actuator, then the optical axis deviation between object lens and the liquid crystal panel is immobilized, and its result produces following problem: the aberration that brings based on optical axis deviation is not limited to the shift position of object lens, but stably produces.
Summary of the invention
The present invention realizes in order to address the above problem that just its purpose is to provide a kind of optical take-up apparatus, even object lens produce lens displacement etc., also can suppress the aberration that produces therefrom effectively in laser.
An optical take-up apparatus that scheme is related of the present invention comprises: LASER Light Source; Object lens, the laser convergence that will penetrate from described LASER Light Source is to recording medium; With the phase place compensating element, be inserted between described LASER Light Source and the described object lens, and only give the spherical aberration correction effect to the part in the described laser in the effective diameter that is included in described object lens, described phase place compensating element is given the spherical aberration correction effect to the described laser in the scope of the center certain distance of the effective diameter of the described object lens of distance, and gives consistent phase place to the extraneous laser of described certain distance.
According to this scheme, do not give the spherical aberration correction effect, and only give the spherical aberration correction effect its part to the whole laser in the effective diameter scope.Thus, even between spherical aberration correction element and object lens, produce optical axis deviation, also can suppress consequent aberration.In addition, about this effect, carry out detailed checking by following embodiment.
In addition, because the present invention does not give the spherical aberration correction effect to the whole laser in the effective diameter scope as described above, and only give the spherical aberration correction effect to its part, so can in the scope of effective diameter, not need the zone of spherical aberration correction effect, the mechanism that configuration is used to give other optical effects.For example, can dispose the mechanism that is used to give the astigmatism correcting action in these other zones.Thus, by a phase place compensating element, can realize the correction of spherical aberration and the correction of astigmatism simultaneously.In addition, if use liquid crystal to constitute the phase place compensating element, then, just can give the correcting action of spherical aberration and the correcting action of astigmatism only by adjusting electrode pattern aptly.Thus, can realize the simplification of phase place compensating element structure.
In addition, when using liquid crystal to constitute the phase place compensating element, can be according to following formation, the phase place compensating element comprises: first electrode; Second electrode, itself and described first electrode contraposition dispose; First alignment films, it is configured in described first electrode and one side described second electrode contraposition; Second alignment films, it is configured in described second electrode and one side described first electrode contraposition; And liquid crystal layer, it is filled between described first alignment films and second alignment films, described first electrode has electrode pattern, and this electrode pattern is used for giving described spherical aberration correction effect to the described laser in the scope of the center certain distance of the described effective diameter of distance.
Description of drawings
Described and other purpose and new feature of the present invention, the following accompanying drawing that is added of contrast are read the explanation of the embodiment shown in following and can more clearly be understood.
Fig. 1 represents the optical system of the optical take-up apparatus that embodiment is related;
Fig. 2 A and B represent the formation and the electrode pattern thereof of the phase place compensating element that embodiment is related;
Fig. 3 A and B represent the formation and the electrode pattern thereof of the phase place compensating element that conventional example (comparative example) is related;
Fig. 4 A and B represent based on the checking result of the related electrode pattern of conventional example (comparative example) with based on the checking result of the related electrode pattern of embodiment;
Fig. 5 A and B represent the variation of the electrode pattern that embodiment is related;
Fig. 6 A～D is the figure of the related astigmatism correcting action of explanation embodiment;
Fig. 7 A and B represent the variation of the electrode pattern that embodiment is related;
Fig. 8 A and B represent the variation of the electrode pattern that embodiment is related.
Embodiment
Below, embodiments of the present invention are described.In addition, about present embodiment, be to have used the present invention in the employed optical take-up apparatus of DVD of future generation (Digital Versatile Disc) at the thick 0.6mm of substrate.
Fig. 1 represents the optical system of the optical take-up apparatus that embodiment is related.In addition, in the figure, for convenience, represented that the circuit that is used for this optical take-up apparatus of drive controlling constitutes (regenerative loop 201, servo circuit 202 and liquid crystal display drive circuit 203).
As shown in the figure, optical take-up apparatus comprises: semiconductor laser 11; Polarization beam splitter (polarized light BS) 12; Collimator (collimator) lens 13; Phase place compensating element 14; Catoptron 15; λ/4 plates 16; Object lens 17; Objective lens actuator 18; Detect lens 19; Photodetector 20.
Catoptron 15 is with will be from the laser of phase place compensating element 14 towards the mode of object lens 17 and erect.λ/4 plates 16 will be circularly polarized light from the laser beam transformation of catoptron 15, and will be from the laser beam transformation of object lens 17 and rectilinearly polarized light from the plane of polarisation quadrature of the laser of catoptron 15.Object lens 17 will be from the laser convergence of λ/4 plates 16 on dish.Objective lens actuator 18 drives object lens 17 according to the drive signal from servo circuit 202 along focus direction and tracking (tracking) direction.
Detect lens 19, can generate focus error signal, in the laser of astigmatism importing from polarized light BS12 based on method of astigmatism.Photodetector 20 is according to the output detection signal by the laser that detects lens 19 convergences.In addition, in photodetector 20, is furnished with the sensing patterns that is used to generate tracking error signal and focus error signal.
Then, with reference to Fig. 2 A, B the formation of phase place compensating element 14 is described.
Fig. 2 A is the sectional side view when the direction of passage of laser cuts off phase place compensating element 14.As shown in the figure, phase place compensating element 14 is made of glass substrate 141 and 142, electrode layer 143 and 144, alignment films 145, liquid crystal layer 146, encapsulant 147.
In addition, the related electrode pattern of present embodiment only disposes 2 ring electrode E12 and E13 in interior perimembranous shown in Fig. 2 B, only is furnished with 1 continual the same ring electrode E14 in its outside.Thus, in the inboard of beam incident diameter (diameter corresponding) and the zone between the electronics E13,, give consistent phase place to laser according to the current potential that is applied to electrode E14 with the effective diameter of object lens 17.
Fig. 3 A, B represent the configuration example of the phase place compensating element of record in the above-mentioned patent documentation 1.Shown in Fig. 3 B, at the electrode layer 143 of this phase place compensating element, at interior perimembranous side configuration circular electrode E21 and 3 ring electrode E22, E23, E24, further inboard slightly in beam incident diameter disposes 3 ring electrode E26 with concentric circles.In its outside, is furnished with ring electrode E27 then.Like this, different with the phase place compensating element that present embodiment is related in the phase place compensating element of above-mentioned patent documentation 1 record, at the inboard slightly electrode that also is formed with ring-type of beam incident diameter.
(checking)
The application's inventors, for the situation of the phase place compensating element that uses the related Fig. 2 of present embodiment with use the situation of the phase place compensating element of the related Fig. 3 of conventional example, carried out the comparatively validate of the generation situation of the corrugated aberration in the beam convergence position.Be explained below.
Fig. 4 A, B represent to verify result's (simulation).In addition, the condition of this checking is as described below.
Numerical aperture of objective: 0.65
Object focal point distance: 2.3mm
The substrate of dish is thick: and 0.585mm (error thick with respect to benchmark=0.015mm)
Use Wavelength of Laser: 407nm
(a-1) of Fig. 4 A, (a-2) and (a-3) be analog result (conventional example) when shown in Fig. 3 B, constituting the pattern of electrode layer 143 like that, (b-1) of Fig. 4 B, (b-2) and (b-3) be analog result (embodiment) when shown in Fig. 2 B, constituting the pattern of electrode layer 143 like that.
In addition, Fig. 4 A (a-1) and Fig. 4 B (b-1) be when not producing optical axis deviation (object lens are with respect to the lens displacement of the optical axis of phase place compensating element) between expression phase place compensating element and the object lens the preceding corrugated of correction (not carrying out the corrugated of corrugated when revising) by the phase place compensating element, revise the figure of relation between corrugated (carrying out revised corrugated, corrugated), back and the liquid crystal phase place (importing the distribution of the phase place of laser by the phase place compensating element) by the phase place compensating element.In addition, Fig. 4 A (a-2) and Fig. 4 B (b-2) be when being illustrated between phase place compensating element and the object lens optical axis deviation (lens displacement) that produces 0.5mm the preceding corrugated of correction, revise the relation between the corrugated and liquid crystal phase place afterwards.In these figure, transverse axis is represented 1/2 of the effective diameter of object lens is made as 1 o'clock diametric(al) distance apart from objective lens optical axis, and the longitudinal axis is represented the distribution standardization with corrugated and phase place.
In addition, Fig. 4 A (a-3) and Fig. 4 B (b-3) is the checking result of the relation of expression lens shift amount and corrugated aberration.In addition, represent at (a-3) with (b-3) except the corrugated aberration (solid line) that adds up to, only to extract the variation (dotted line) of 3 spherical aberrations.
In addition, in this checking, phase place compensating element and the embodiment related phase place compensating element related to conventional example apply the current potential of the liquid crystal phase place shown in (b-1) of (a-1) that produce Fig. 4 A and Fig. 4 B via the electrode E21～E27 of each electrode layer 143 and electrode E11～E14.
At first with reference to (a-1) of Fig. 4 A and (b-1) of Fig. 4 B, when object lens do not produce optical axis deviation (lens displacement), if use the related phase place compensating element of conventional example, then in gamut roughly, the corrugated state of laser is corrected, and if use the related phase place compensating element of embodiment, the corrugated state that then can be observed the beam diameter peripheral part produces bigger variation.At this moment, if ask for the corrugated aberration of beam convergence position, the corrugated aberration when then having used the related phase place compensating element of conventional example is 7.4m λ rms, and the corrugated aberration when using the related phase place compensating element of embodiment is 23.0m λ rms.Therefore, the aberration capability for correcting when not producing the lens displacement we can say that related phase place compensating element one side of conventional example is more excellent.
Relative therewith, produced optical axis deviation when displacement (lens) of 0.5mm at object lens, shown in Fig. 4 A (a-2) and Fig. 4 B (b-2), the situation of the phase place compensating element that the situation of the phase place compensating element that the use conventional example is related is related with using embodiment is compared, and it is big that the variation of the corrugated state of beam diameter direction becomes.At this moment, if ask for the corrugated aberration of beam convergence position, rise to 44.8m λ rms by leaps and bounds when then using the related phase place compensating element of conventional example, and be suppressed at 37.3m λ rms when using the related phase place compensating element of embodiment.Therefore as can be known, the aberration capability for correcting when producing the lens displacement, related phase place compensating element one side of embodiment is more excellent.
Further, with reference to (a-3) of Fig. 4 A and (b-3) of Fig. 4 B, the aberration capability for correcting that compares the related phase place compensating element of related phase place compensating element of conventional example and embodiment, about the corrugated aberration that adds up to, when the lens shift amount is the 0.2mm left and right sides, the aberration capability for correcting of two phase place compensating elements is a same degree, and big if the lens shift amount further becomes, then the phase place compensating element of present embodiment more can be brought into play excellent aberration capability for correcting.Especially, 3 spherical aberration compositions that cause about thick error of substrate etc., the lens shift amount surpasses about 0.15mm as can be known, and the aberration capability for correcting of two phase place compensating elements is a same degree, and the phase place compensating element of present embodiment can be brought into play more excellent capability for correcting afterwards.
Like this,, compare the corrugated aberration that produces in the time of more effectively to suppress the lens displacement with conventional example according to present embodiment.In addition,, relatively with reference to Fig. 2 A, B and Fig. 3 A, B as can be known, the quantity of the electrode pattern of electrode layer can be reduced, the simple in structure of phase place compensating element can be made according to present embodiment.
In addition, in the above-described embodiment,, not have the electrode E14 of interruption in the configuration of the outside of the electrode E13 of ring-type, but in this zone, can dispose the electrode that is used to revise other aberrations yet with reference to Fig. 2 A and B.
Configuration example when Fig. 5 A and B are the electrode E31 that use in the correction of the outside of the electrode E13 of ring-type configuration astigmatism～E38.In addition, because the aberration function of astigmatism and the aberration function of spherical aberration are independent of each other mutually, so even the electrode E31～E38 that uses in the correction of the outside of the electrode E13 of ring-type configuration astigmatism implements the astigmatism correcting action simultaneously like this, also can not can the correcting action of spherical aberration be impacted.
In addition, when revising astigmatism, the electrode that is in diagonal positions among electrode E31～E38 is mutually applied identical current potential.For example, shown in Fig. 6 A top, to E31 and E35 this is a pair of, with E34 and this a pair of current potential V1 that applies of E38, this is a pair of, this a pair ofly applies the current potential V2 different with current potential V1 with E33 and E37 to E32 and E36.Thus, shown in the below of Fig. 6 A, can make the phase place compensating element produce peak and the such PHASE DISTRIBUTION of paddy that occurs phase place along the light beam circumferencial direction by per 90 degree.Its result can import the astigmatism correcting action to the laser by the phase place compensating element.
In addition, shown in Fig. 6 B, C, D, suitably change, the direction of the astigmatism of light beam circumferencial direction is changed by making the electrode that is applied in current potential.Shown in Fig. 5 A, B, electrode along the circumferential direction by the situation of 8 five equilibriums under, the direction that can make astigmatism changes by per 22.5 degree.
In addition, shown in Fig. 7 A, B, also the electrode that can further the astigmatism correction be used is divided into two parts on the radiation direction.So, even the variation that also can have phase place on the radiation direction can import finer spherical aberration correction effect and astigmatism correcting action.
But, in above-mentioned, only dispose the electrode pattern of the correcting action that is used to import spherical aberration and astigmatism in the electrode layer 143 in 2 electrode layers 143,144, but can also in another electrode layer 144, dispose the electrode pattern that is used to revise other aberrations.
For example, in electrode layer 144,,, can make the phase place compensating element have the PHASE DISTRIBUTION that is used to give the coma aberration correcting action then by the current potential that applies of control electrode E41～E45 as if the electrode pattern shown in the arrangement plan 8A.In addition, because aberration function and the aberration function of astigmatism and the aberration function of spherical aberration of coma aberration is independent of each other mutually, even the electrode E41～E45 that uses in electrode layer 144 configuration coma aberration corrections implements the coma aberration correcting action simultaneously like this, can not impact the correcting action of spherical aberration and the correcting action of astigmatism yet.
In addition, electrode pattern that also can application drawing 2B is as the electrode pattern of electrode layer 143, for example, shown in Fig. 8 B, with the electrode pattern of electrode layer 144 as the electrode pattern that carries out the correcting action of astigmatism and coma aberration simultaneously.At this moment, the voltage that imposes on electrode E31～E38 by control is revised astigmatism, and the voltage that imposes on electrode E41～E43 by control is revised coma aberration.
More than, embodiments of the present invention are illustrated, but the present invention being defined in this, its embodiment also can have various changes in addition.
For example, in the above-described embodiment, illustration apply the present invention in the optical take-up apparatus that DVD of future generation uses, in addition, also can be applied in the exchange type optical take-up apparatus of light picker that DVD uses or DVD of future generation and DVD.In addition, in the above-described embodiment, configuration phase compensating element 14 is revised the aberration on the CD on 17 the light path from semiconductor laser 101 to object lens, but in order to revise the aberration on the photodetector 20, also can dispose other aberration compensating element on light path.
In addition, in the above-described embodiment, for example with reference to (b-1) of Fig. 4 B, liquid crystal phase place than the position scope more in the outer part about the center 0.5mm along the object lens direction of displacement apart from transverse axis is certain, but the liquid crystal phase place is certain start position is not to be defined in this, for example also can begin to make the liquid crystal phase place certain than 0.5mm position more in the outer part, distance center, at this moment, the width or the progression of the ring electrode of perimembranous in adjusting aptly.
And, in the above-described embodiment, same (b-1) with reference to Fig. 4 B, liquid crystal phase place than the position scope more in the outer part about the center 0.5mm along the object lens direction of displacement apart from transverse axis is certain, but for example also can be than the position scope more in the outer part about the 0.5mm of distance center, the liquid crystal phase place promoted a bit, begin so also can obtain and the roughly same effect of checking shown in Fig. 4 B from the position that has promoted for necessarily even make than this liquid crystal phase place more in the outer part.At this moment, dispose the electrode that is used to promote the liquid crystal phase place in addition.
In addition, embodiments of the present invention can be carried out various changes aptly in the scope of the technological thought shown in the scope of technical scheme.
Claims (5)
1. optical take-up apparatus, comprising:
LASER Light Source;
Object lens make the laser convergence that penetrates from described LASER Light Source to recording medium; With
The phase place compensating element is inserted between described LASER Light Source and the described object lens, and only gives the spherical aberration correction effect to the part in the described laser in the effective diameter that is included in described object lens,
Described phase place compensating element is given the spherical aberration correction effect to the described laser in the scope of the center certain distance of the effective diameter of the described object lens of distance, and gives consistent phase place to the extraneous laser of described certain distance.
2. optical take-up apparatus according to claim 1 is characterized in that,
Described phase place compensating element comprises:
First electrode;
Second electrode is with described first electrode contraposition configuration;
First alignment films is configured in described first electrode and one side described second electrode contraposition;
Second alignment films is configured in described second electrode and one side described first electrode contraposition; With
Liquid crystal layer is filled between described first alignment films and described second alignment films,
Described first electrode has electrode pattern, and this electrode pattern is used for giving described spherical aberration correction effect to the described laser in the center certain distance of described effective diameter.
3. optical take-up apparatus according to claim 1 is characterized in that,
Described phase place compensating element in the outside apart from the scope of the center certain distance of described effective diameter, imports the optical effect beyond the correcting action of described spherical aberration to described laser.
4. optical take-up apparatus according to claim 3 is characterized in that,
Described phase place compensating element comprises:
First electrode;
Second electrode is with described first electrode contraposition configuration;
First alignment films is configured in described first electrode and one side described second electrode contraposition;
Second alignment films is configured in described second electrode and one side described first electrode contraposition; With
Liquid crystal layer is filled between described first alignment films and described second alignment films,
Described first electrode has electrode pattern, this electrode pattern is given described spherical aberration correction effect to the described laser in the center certain distance of described effective diameter, and the optical effect beyond the correcting action of described laser being given described spherical aberration apart from the outside of the scope of the center certain distance of described effective diameter.
5. according to claim 3 or 4 described optical take-up apparatus, it is characterized in that,
Described phase place compensating element in the outside apart from the scope of the center certain distance of described effective diameter, is given the astigmatism correcting action to described laser.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2005334708 | 2005-11-18 | ||
| JP2005334708 | 2005-11-18 | ||
| JP2005341551 | 2005-11-28 |
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| CN1967682A CN1967682A (en) | 2007-05-23 |
| CN100454412C true CN100454412C (en) | 2009-01-21 |
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| Application Number | Title | Priority Date | Filing Date |
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| CNB2006101603497A Expired - Fee Related CN100454412C (en) | 2005-11-18 | 2006-11-15 | Optical pickup device |
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Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101566749B (en) * | 2008-04-25 | 2011-12-21 | 鸿富锦精密工业（深圳）有限公司 | Liquid crystal lens and lens module |
| CN105866998A (en) * | 2016-06-02 | 2016-08-17 | 京东方科技集团股份有限公司 | Display device |
| CN108188513A (en) * | 2018-01-02 | 2018-06-22 | 青岛理工大学 | Double-edge annular electrode for laser electrochemical composite machining |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1598942A (en) * | 2003-09-15 | 2005-03-23 | 三星电子株式会社 | Optical pick-up having a spherical aberration compensator and a method of compensating for spherical aberration |
| CN1685411A (en) * | 2002-11-08 | 2005-10-19 | 西铁城时计株式会社 | Liquid crystal optical element and optical device |
| WO2005106865A1 (en) * | 2004-04-28 | 2005-11-10 | Pioneer Corporation | Aberration corrector, aberration correcting method, optical pickup |
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2006
- 2006-11-15 CN CNB2006101603497A patent/CN100454412C/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1685411A (en) * | 2002-11-08 | 2005-10-19 | 西铁城时计株式会社 | Liquid crystal optical element and optical device |
| CN1598942A (en) * | 2003-09-15 | 2005-03-23 | 三星电子株式会社 | Optical pick-up having a spherical aberration compensator and a method of compensating for spherical aberration |
| WO2005106865A1 (en) * | 2004-04-28 | 2005-11-10 | Pioneer Corporation | Aberration corrector, aberration correcting method, optical pickup |
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