CN101149938A - Objective lens actuator, diffractive optical element, and optical pickup device - Google Patents

Objective lens actuator, diffractive optical element, and optical pickup device Download PDF

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Publication number
CN101149938A
CN101149938A CNA2007101533605A CN200710153360A CN101149938A CN 101149938 A CN101149938 A CN 101149938A CN A2007101533605 A CNA2007101533605 A CN A2007101533605A CN 200710153360 A CN200710153360 A CN 200710153360A CN 101149938 A CN101149938 A CN 101149938A
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China
Prior art keywords
object lens
optical element
diffractive optical
protuberance
fixture
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CNA2007101533605A
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Chinese (zh)
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田中聪弘
中沼宽
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Ricoh Co Ltd
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Ricoh Co Ltd
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  • Optical Recording Or Reproduction (AREA)

Abstract

An objective lens is directly fixed to one surface of a lens holder. Driving coils that generate focusing thrust and tracking thrust are provided in the lens holder, which is elastically supported by supporting springs according to an amount of thrust generated by the driving coils. A compatible diffractive optical element that outputs a laser beam and is compatible with a reflection signal of the laser beam is directly fixed to the lens holder on the rear side of the objective lens. An inertia ballast is provided on the other surface of the lens holder.

Description

Objective lens actuator, diffractive optical element and optical pick-up device
The application number that it is 2006-253053 that the application is included in the application number of Japanese publication on September 19th, 2006 by reference, apply on November 16th, 2006 is 2006-310093, apply on November 24th, 2006 application number is 2006-316732 and applies on Dec 28th, 2006 application number and be the priority document of 2006-353594 and advocate the right of priority of these files.
Technical field
The present invention relates to objective lens actuator, diffractive optical element and optical pick-up device.
Background technology
Objective lens actuator is used to apply focus control and tracking Control to object lens in optical pick-up device etc.For example, No. the 3754225th, Jap.P. and Japanese publication have disclosed a kind of objective lens actuator 2005-310315 number and 2004-103076 number, use the electric object lens location of directly regulating when controlling high speed of drive coil.
Move it the expectation position in order to control object lens, the weight that comprises the removable unit of the object lens fixture that keeps object lens must be light, thereby the structure of removable unit must be firm can be owing to high-speed motion etc. makes internal modification, the structure of removable unit and assembly must be able to be resisted the heat that the power consumption of drive coil causes and take place, must satisfy the Abbe principle, this is for the necessary principle of the structure of accurate driving mechanism.
According to the Abbe principle, in order to prevent that when expecting the removable unit of translation or preventing the phenomenon of violating the Abbe principle removable unit from tilting, when driving mechanism has low frequency driving feature, driving force need act on the center of the support spring of supporting removable unit, when driving mechanism had high-frequency driving feature, driving force need act on the center of inertia of removable unit.
In other words, under the situation of objective lens actuator, the center of inertia of the elastic center of the support spring of the thrust center of drive coil, the removable unit of support and the mass distribution of removable unit must overlap each other.
On the other hand, the high density that is applied to pickup regulator or is applied to the high aperture of having of a plurality of optical maser wavelengths ratio has relative big quality with the high capacity object lens.
Therefore, in order to satisfy the Abbe principle, inevitably, the inertia ballast quality in the center of inertia that is used to regulate object lens is just big.
When the compatible diffractive optical element that will be used for a plurality of optical maser wavelengths was increased to removable unit, the quality of removable unit increased.Because the increase of removable element quality worsens the susceptibility in inertia zone (high-frequency zone), power consumption also can increase.
Therefore, because the hot generating capacity of drive coil increases, the increase of power consumption can worsen the heat hardiness of removable unit block.When the assembly that will have big relatively quality is connected to removable unit outside, be difficult to guarantee structure firm of removable unit.In addition, the internal modification of decline of mass distribution rate and removable unit makes resonance characteristics worsen.The result is that the controlling features of removable unit can be worsened.
Figure 28 A to 28C is the synoptic diagram of regulator, has wherein increased the compatible diffractive optical element that is used for a plurality of optical maser wavelengths on removable unit.Figure 28 A is the front view of objective lens actuator, and Figure 28 B is a side view, and Figure 28 C is a backplan.In Figure 28 A, the vertical direction on the paper surface is the tangential direction on CD, and vertical direction as for paper surface is a focus direction, and the horizontal direction on the paper surface is radial direction (tracking direction).In the following description, vertical direction and horizontal direction are based on Figure 28 A.
Objective lens actuator comprises the stator unit 1 on the optical information recording/reclaim equiment that is installed in optical pick-up device for example.Stator unit 1 comprises rectangular basically base portion 2, lay respectively at the top and following yoke 2a and the 2b of base portion 2, be fixed on magnet 3a and 3b on yoke 2a respect to one another and the 2b, the removable unit 4 between magnet 3a and 3b and be fixed on another surperficial base 5 of yoke 2a.
Removable unit 4 comprises the object lens fixture 7 that keeps object lens 6, the drive coil 8 that is used to focus on, the drive coil 9 that is used to follow the tracks of, a plurality of (in this example, totally 4) support spring 10 (end is inserted through base 5), (other end of supporting spring 10 is by the welding function to be used for fixing the printed-wiring board (PWB) 11 of supporting spring and feeding drive coil power, for example machinery welding and electric welding, be fixed on the printed-wiring board (PWB) 11) and be fixed on the rear surface and the main inertia ballast 12 of eliminating the inertia main force square of object lens 6 of object lens fixture 7.Support an end of spring 10 to be connected with the welding function of electric welding and to be fixed on the flexible printed-wiring board (PWB) 13 by for example machinery welding, printed-wiring board (PWB) 13 is arranged in base 5 flexibly.
But diffractive optical element 14 and object lens 6 are fixed on the object lens fixture 7 as compatible elements by picture frame 15, can be in many type disks recorded information and regenerating information or recorded information and regenerating information from many type disks.
In above-mentioned objective lens actuator, object lens 6 and diffractive optical element 14 are fixed to object lens fixture 7 by object lens fixture 7.Therefore, because the thickness of picture frame 15, the profile of object lens fixture 7 has increased in radial direction and tangential direction.The result is that the quality of removable unit 4 can increase, its firm can reduction.
Because the aperture of object lens 6 and CD is than relation, object lens 6 must be positioned at the position near the upper end of removable unit 4.Object lens 6, diffraction Guangyuan part 14 and picture frame 15 all are positioned on the structure centre of thrust center that comprises drive coil 8 and the center of supporting spring 10 in focus direction.The result is that the weight of the inertia ballast 12 of the inertia main force square of cancellation object lens 6, diffraction Guangyuan part 14 and picture frame 15 must increase.
Be used for diffractive optical element 14 when forming the diffractive optical element 14 of superior structural when having the resin material lower than the heat hardiness of glass material, opposing drive coil 8 and 9 pyrogenetic reliability can be worsened.This is because diffractive optical element 14 is surrounded by the removable unit 4 in the environment that is in relatively hot.
As the device of store video information, acoustic information or data on computers, the optical recording media that for example has the CD that recording capacity is 0.65 GB (GB) (CD) and have a Digital video disc that recording capacity is 4.7 GB (GB) (DVD) just is used widely.In the last few years, more and more stronger demand was arranged with further raising recording density and increase recording capacity.
As the device of the recording density that improves these optical recording medias, increase to severals holes of optical recording media write information or the object lens from the optical pick-up of optical recording media read message (NA) thereby or the wavelength that the reduces light source diameter that reduces the beam spot that is formed on the optical recording media and compresses by object lens be effective.
Therefore, for example, in " CD optical recording media ", the NA of object lens be set to 0.50 and the wavelength of light source be set to 780nm.On the other hand, have than " CD optical recording media " more in " the DVD optical recording media " of high record density, the NA of object lens be set to 0.65 and the wavelength of light source be set to 660nm.As mentioned above, recording density and the recording capacity of more and more stronger demand with further raising optical recording media arranged.Therefore, the NA of object lens need be increased to greater than 0.65 or the wavelength of light source is reduced to less than 60nm.
For such high capacity optical recording media and optical information processing device, " Blu-ray disc " (BD) standard has been proposed, use the capacity of guaranteeing to equal 22GB at the light source in blue light wavelength zone and object lens with NA of 0.85.
Also have a standard be " HD-DVD " (HD), use the capacity of guaranteeing to equal 20GB at the same light source in blue light wavelength zone and object lens with 0.65NA.
In last standard,, increase capacity by reducing wavelength and increasing NA than those DVD optical recording medias.In one standard of back, handle rather than do not carry out increase NA by modelled signal and can improve linear recording density, and by adopting bank/ditch record increase capacity.
BD and HD are common, because used the royal purple semiconductor laser light source with the oscillation wavelength that is approximately 405nm.Yet optical recording media has the substrate thickness that is respectively 0.1mm and 0.6mm.
Even the record that can carry out high density information and regenerate arbitrary or both optical pick-up in, need guarantee the recording of information of the CD that is used for providing in a large number and DVD and regeneration is arbitrary or both.Expectation has the light source of suitable wavelength according to the type selecting of optical recording media (be used for recorded information or from its regenerating information), to the suitable optical processing of selected light source applications, and proofreaies and correct because the spherical aberration that the difference of the substrate thickness of optical recording media causes.For example, Japanese patent application has disclosed a kind of technology of proofreading and correct aberration for 2006-12393 number, proposes a kind of aberration correction element with diffraction structure.
Yet the aberration correction element (diffractive optical element) with this spline structure has at the lip-deep meticulous coaxial and concentric diffraction structure of plane component.This diffraction structure is formed at two surfaces of aberration correction element (diffractive optical element).Each surface has different diffraction structures and the aberration correction function that has corresponding to the standard of Different Light wavelength and different optical recording media.
When such planar diffraction optical element is installed in optical pick-up etc. and goes up, anti-if the front-end and back-end of element connect, just can not get suitable aberration correction function.In addition, as the component shape in past, element has the external structure with the thickness direction symmetry on a surface, and finish outside the zone on cylindrical aberration correcting element surface on another outside surface.Therefore, be easy to the front-end and back-end of element are connected on the object lens holding member instead.
In the example in the past, can realize reducing the regulator that diffractive optical element is installed removable cellular construction weight and increase that it is firm, and prevent pyrolytic damage to diffractive optical element.Yet consideration connects the accuracy and the angle of diffractive optical element.When complete coaxial connection of object lens and diffractive optical element, thereby the regular reflection of the planar section of diffractive optical element can be changed into back light and generate flash of light and causes confusion etc.
Consider to prevent flash of light, Japanese patent application has disclosed a kind of exemplary device that prevents this problem for 2006-139874 number.Yet, existing problems aspect the function of removable cellular construction described later and reliability.
Thereby proposed to install obliquely diffractive optical element and prevented the measure of glistening.Proposed the structure that this inclination is installed, that is, diffraction Guangyuan part is installed as the structure with respect to the inclined light shaft of object lens.
Usually, for improve as the axle rotor optical element degree easy to manufacture be connected accuracy, provide cylindrical in the outside of optical element or the cylindricality axostylus axostyle, provide circular hole or classification circular hole on the relative parts of optical element having connected, by axostylus axostyle being assemblied in the location of carrying out in the circular hole to optical element.
When using concentric diffractive optical element, following requirement is arranged to satisfy the function of element as compatible elements.At first, need the optical axis of location, high precision ground object lens and the optical axis of diffractive optical element.Secondly, because it is the plane that two surfaces of compatible diffractive optical element all have the end face of step (step) and step, the integrated plane that is equal to whole effective diameter to the plane of these steps, and, because the flash of light that causes of regular reflection, the screen portions of step need be done a little inclination with respect to the vertical direction of the optical axis of object lens in order to prevent.
When the clinoplane part, the center of diffractive optical element that should location, high precision ground with respect to the optical axis of object lens is actually the center of object lens side surface.Be used for can the use of using in the future have three or the situation of the diffractive optical element of the compatible light system of the light source of a plurality of wavelength under, select with two wavelength in the past or the hole limiting element is compared, require extreme high precision location.
The center on the surface that tilts for high precision ground location need be at the relative parts of objective lens actuator shown in Figure 28, for example as the object lens fixture 7 of movable housing, in provide the hole with respect to object lens 6 to tilt the hole,
When having used the parts that are used to form the shape that is difficult for formation, reliability is worsened probably.
In the example in above-mentioned past, object lens are as the installed with built-in component that is used for the mirror frame of object lens fully.Yet, use this mirror frame that is used for object lens fully to cause the increase of movable housing size and the quality that is used for the counterweight of object lens, mirror frame and movable housing increases.The increase of size and the increase of quality cause the reduction of high-order resonant frequency.Particularly, when by fixing use mirror frame such as welding have the inner matter mirror assembly of big quality and moment of inertia the time because the firm deficiency of welding, the influence of the deterioration of high-order resonance characteristics is just greatly.
Summary of the invention
The objective of the invention is to solve the problems of the prior art to small part.
According to an aspect of the present invention, objective lens actuator comprises the object lens fixture that object lens is remained on the first surface side, be provided in the object lens fixture and produce and focus on thrust and the drive coil of following the tracks of thrust, flexibly support the elastic supporting member of object lens fixture according to the thrust amount of drive coil generation, be positioned at object lens light incident side, outgoing laser beam and and the diffractive optical element of the reflected signal compatibility of laser beam and be positioned at the inertia ballast of object lens fixture second surface side.Object lens and diffractive optical element directly are fixed to object lens fixture.
According to a further aspect in the invention, in the diffractive optical element of support corresponding to the compatibility of the optical recording media of at least three kinds of various criterions of the light source of at least three kinds of different wave lengths, diffractive optical element is concentric diffraction.Diffractive optical element comprises first surface and second surface, each surface all comprises the aberration correction zone that corresponds respectively to different wave length and various criterion, first outer peripheral areas on the first surface and second outer peripheral areas on the second surface, first outer peripheral areas and second outer peripheral areas are that appearance is asymmetrical.
Read following detailed description in conjunction with the accompanying drawings and can understand above and other objects of the present invention, feature, advantage and technology and industrial significance better about the preferred embodiment of the present invention.
Description of drawings
Figure 1A is the front view according to the objective lens actuator of first embodiment of the invention;
Figure 1B is the side view of the objective lens actuator shown in Figure 1A;
Fig. 1 C is the backplan of the objective lens actuator shown in Figure 1A;
Fig. 2 A is the front view according to the objective lens actuator of second embodiment of the invention;
Fig. 2 B is the side view of the objective lens actuator shown in Fig. 2 A;
Fig. 2 C is the backplan of the objective lens actuator shown in Fig. 2 A;
Fig. 3 A is the front view according to the objective lens actuator of third embodiment of the invention;
Fig. 3 B is the side view of the objective lens actuator shown in Fig. 3 A;
Fig. 3 C is the backplan of the objective lens actuator shown in Fig. 3 A;
Fig. 4 A is the front view according to the objective lens actuator of fourth embodiment of the invention;
Fig. 4 B is the routine view of the objective lens actuator shown in Fig. 4 A;
Fig. 4 C is the backplan of the objective lens actuator shown in Fig. 4 A;
Fig. 5 is the synoptic diagram according to the optical pick-up of fifth embodiment of the invention;
Fig. 6 is the sectional view of the amplification of aberration correction element;
Fig. 7 A is the planimetric map of first Difraction surface of aberration correction element;
Fig. 7 B is the planimetric map of second Difraction surface of aberration correction element;
Fig. 8 is the sectional view of the amplification of the part by the aberration correction element;
Fig. 9 A is the synoptic diagram that is connected to the aberration correction element with classification circular outer shape on the object lens fixture parts;
Fig. 9 B is the synoptic diagram that is connected to the aberration correction element with classification square outer shape on the object lens fixture parts;
Figure 10 A is the synoptic diagram that is connected to the aberration correction element with awl circular outer shape on the object lens fixture parts;
Figure 10 B is the synoptic diagram that is connected to the aberration correction element with awl square outer shape on the object lens fixture parts;
Figure 11 A is a synoptic diagram of describing flash of light incident on light receiving element;
Figure 11 B describes the synoptic diagram of flash of light away from the state of light receiving element;
Figure 12 A is a synoptic diagram of having considered the aberration correction element that is connected to the classification circular outer shape on the object lens fixture parts of flash of light;
Figure 12 B is a synoptic diagram of having considered the aberration correction element that is connected to the classification square outer shape on the object lens fixture parts of flash of light;
Figure 13 A is a synoptic diagram of having considered the aberration correction element that is connected to the awl circular outer shape on the object lens fixture parts of flash of light;
Figure 13 B is a synoptic diagram of having considered the aberration correction element that is connected to the awl square outer shape on the object lens fixture parts of flash of light;
Figure 14 is the skeleton view of the regulator of optical pick-up;
Figure 15 is the block diagram of optical information processing apparatus;
Figure 16 is the fragmentary cross-sectional view according to the object lens fixture of the objective lens actuator of seventh embodiment of the invention;
Figure 17 is the fragmentary cross-sectional view according to the object lens fixture of the objective lens actuator of eighth embodiment of the invention;
Figure 18 is the fragmentary cross-sectional view according to the object lens fixture of the objective lens actuator of ninth embodiment of the invention;
Figure 19 is the fragmentary cross-sectional view according to the object lens fixture of the objective lens actuator of tenth embodiment of the invention;
Figure 20 is the fragmentary cross-sectional view according to the object lens fixture of the objective lens actuator of eleventh embodiment of the invention;
Figure 21 A is the sectional view according to the object lens fixture of the objective lens actuator of twelveth embodiment of the invention;
Figure 21 B is the backplan of the last shell of the objective lens actuator shown in Figure 21 A;
Figure 22 is the fragmentary cross-sectional view according to the object lens fixture of the objective lens actuator of thriteenth embodiment of the invention;
Figure 23 is the fragmentary cross-sectional view according to the object lens fixture of the objective lens actuator of fourteenth embodiment of the invention;
Figure 24 is the fragmentary cross-sectional view according to the object lens fixture of the objective lens actuator of fifteenth embodiment of the invention;
Figure 25 is the fragmentary cross-sectional view according to the object lens fixture of the objective lens actuator of sixteenth embodiment of the invention;
Figure 26 is the fragmentary cross-sectional view according to the object lens fixture of the objective lens actuator of seventeenth embodiment of the invention;
Figure 27 is the synoptic diagram according to the optical pick-up device that objective lens actuator is installed of embodiment;
Figure 28 A is the front view of existing objective lens actuator;
Figure 28 B is the side view of existing objective lens actuator; With
Figure 28 C is the backplan of existing objective lens actuator.
Embodiment
Describe example embodiment of the present invention in detail below with reference to accompanying drawing.In all accompanying drawings, identical Reference numeral indication corresponding elements.
Figure 1A is the front view according to the objective lens actuator of first embodiment of the invention.Figure 1B is the side view of the objective lens actuator shown in Figure 1A.Fig. 1 C is the backplan of the objective lens actuator shown in Figure 1A.The vertical direction of paper surface is the tangential direction on CD in Figure 1A, and vertical direction as for paper surface is to focus on, and the horizontal direction of paper surface is radial direction (tracking direction).In the following description, vertical direction and horizontal direction are all based on Figure 1A.
Objective lens actuator comprises the stator unit 21 that is installed on optical information recording/reclaim equiment.Stator unit 21 comprises rectangular basically base portion 22, lay respectively at the top and following yoke 22a and the 22b of base portion 22, be fixed on magnet 23a and 23b on yoke 22a respect to one another and the 22b, removable unit 24 between magnet 23a and 23b and be fixed on another surperficial base 25 of yoke 22a.
Removable unit 24 comprises the object lens fixture 27 that keeps object lens 26, the drive coil 28 that is used to focus on, the drive coil 29 that is used to follow the tracks of, a plurality of (in this example, totally 4) support spring 30 (end is inserted through base 5), (other end of supporting spring 30 is by the welding function to be used for fixing the printed-wiring board (PWB) 11 of supporting spring and feeding drive coil power, for example machinery welding and electric welding, be fixed on the printed-wiring board (PWB) 31) and be fixed on the rear surface and the main inertia ballast 32 of eliminating the inertia main force square of object lens 26 of object lens fixture 27.
The optical axis that removable unit 24 is configured to its operation center and object lens 25 overlaps each other.Support an end of spring 30 to be connected with the welding function of electric welding and to be fixed on the flexible printed-wiring board (PWB) 33 by for example machinery welding, printed-wiring board (PWB) 33 is arranged in base 25 flexibly.The padded coaming (figure does not show) that is used for slowing down vibration is embedded in base 25 and supports spring 30 to surround.
Drive coil 28 that is used to focus on and the drive coil 29 that is used to follow the tracks of are electrically connected to be used for fixing on the printed circuit board (PCB) 31 supports spring and feeding drive coil power.
In this embodiment, support that spring 30 is metal springs.As the fixing method of supporting spring 30, support spring 30 to be fixed on the printed circuit board (PCB) 31 with fixing spring and the feeding drive coil power supported by the welding function of machinery welding and electric welding.Yet, can use the support spring 30 of any material and any section shape.As the fixing method of supporting spring 30, can use the method for for example welding and insert molding.
But object lens 26 directly are fixed on the object lens fixture 27 as compatible elements, with diffractive optical element 34 separately the time, can be in many type disks recorded information and regenerating information or recorded information and regenerating information from many type disks.
On the other hand, diffractive optical element 34 directly is fixed on the end of the object lens fixture 27 of the offside that is positioned at object lens 26.Diffractive optical element 34 is formed from a resin.Therefore, can make fine pattern with low cost in high precision ground, and easily diffractive optical element 34 is connected to object lens fixture 27, also can carry out the center adjustment of diffractive optical element 34 etc.
In this structure, can make the picture frame 15 (seeing Figure 28) in the above-mentioned structure in the past unnecessary, and the outer shape of removable unit 24 be reduced the thickness of picture frame 15.Therefore, can help reducing the size and the weight of removable unit 24.
The inertia main force square of diffractive optical element 34 has the effect of the inertia main force square that remedies object lens 26.Therefore, can reduce the weight of inertia ballast 32 and help further reducing the weight of removable unit 24.
In addition, there is not installation component to be assemblied on the object lens fixture 27 to prevent object lens 26 and diffractive optical element 34.Therefore, can easily object lens 26 and diffractive optical element 34 be assemblied on the object lens fixture 27.
Fig. 2 A is the front view according to the objective lens actuator of second embodiment of the invention.Fig. 2 B is the side view of objective lens actuator.Fig. 2 C is the backplan of objective lens actuator.According to the objective lens actuator of second embodiment basically with first embodiment in identical, same description has not just repeated.
In this second embodiment, inertia ballast 42 is sheet metals, can easily make and inexpensive.Inertia ballast 42 is installed on the whole substantially surface of lowermost end of object lens fixture 47, and diffractive optical element 34 is foreclosed.This feasible structure that can strengthen comprising object lens fixture 47 and inertia ballast 42 by mutual reinforcing, independent each in object lens fixture 47 and the inertia ballast 42 all can not guarantee to realize reducing the firm of weight easily.
Inertia ballast 42 can be positioned at the position of diffractive optical element 34 from the heat shielding of drive coil 28 and 29, and can form by having the position of highdensity material at distance diffractive optical element fixed range.Therefore, can estimate the effect of heat sink and further improve the pyrogenetic heat hardiness of opposing drive coil 28 and 29 by the zone of regulating inertia ballast 42.
Fig. 3 A is the front view according to the objective lens actuator of third embodiment of the invention.Fig. 3 B is the side view of objective lens actuator.Fig. 3 C is the backplan of objective lens actuator.According to the objective lens actuator of the 3rd embodiment basically with first embodiment in identical, same description has not just repeated.
In the 3rd embodiment, inertia ballast 52 is fixed on four angles of periphery of object lens fixture 57 to form breach 50.Therefore, even take place in moulding or connection procedure in object lens fixture 57, inertia ballast 52 etc. or surround or take place because sinking or the encirclement that heat causes, the effect of mutual reinforcing that can be by object lens fixture 57, inertia ballast 52 etc. remedies or encirclement.
Fig. 4 A is the front view according to the objective lens actuator of fourth embodiment of the invention.Fig. 4 B is the side view of objective lens actuator.Fig. 4 C is the backplan of objective lens actuator.According to the objective lens actuator of the 4th embodiment basically with first embodiment in identical, same description has not just repeated.
In the 4th embodiment, shown in Fig. 4 B and 4C, the drive coil 28 of object lens fixture 67 and 29 and inertia ballast 62 between filled silicon materials 60.Form passage from drive coil 28 and 29 to inertia ballast 62 with low heat hardiness as heat sink as thermal source.In this way, the heat that prevents drive coil 28 and 29 is sent to diffractive optical element 34.
As mentioned above, can when increasing, the quality that minimizes removable unit 4 generate passage with low heat hardiness.Therefore, can allow the heat of drive coil 28 and 29 to flee from, strengthen inertia ballast 62 as the function of heat sink and improve the reliability of the optical property of objective lens actuator to inertia ballast 62 sides rather than object lens fixture 27 sides.
Be mounted in according to the objective lens actuator of the embodiment of the invention and be used on CD recorded information on the adapter and, can drive two the axle translations of object lens in above-mentioned focus direction and radial direction from the objective lens actuator of optical disc reproducing information.In addition, do not say that the present invention can be applied to, for example, except this diaxon driven in translation, can comprise that radial axle and tangent line axle slant correction three or four axles drive the regulator of object lens and the drive coil that the diaxon that is used for removable unit at least drives be installed or be used for that three of removable unit drive or the regulator of four shaft-driven drive coils.
Fig. 5 is the synoptic diagram according to the optical pick-up of fifth embodiment of the invention.This optical pick-up be record the information in for example use the Different Light wavelength in three kinds of optical recording medias (BD, DVD and CD recording medium) in the different numbers hole (NA) of single object lens 108 and from the compatible light adapter of these three kinds of optical recording media regenerating informations.
BD, DVD and CD optical recording media 109a, the substrate thickness of 109b and 109c is respectively 0.1mm, 0.6mm and 1.2mm.Corresponding to BD, DVD and CD optical recording media 109a, several holes (NA) of 109b and 109c are respectively 0.85,0.65 and 0.50.The wavelength X 1 of first, second and the 3rd light source, λ 2 and λ 3 are respectively 395nm to 415nm, 650nm to 670nm and 770nm to 805nm.
Optical pick-up comprises, for BD optical record medium 109a, semiconductor laser 101, calibration mirror 102, polarization electron beam splitter 103, wavelength are selected electron beam splitter 104, deviation prism 105,1/4 ripple plate 106, aberration correction element (diffractive optical element) 107, object lens 108, are detected mirror 110 and light receiving element 112.Centre wavelength as the semiconductor laser 101 of first light source is 405nm, and several holes (NA) of object lens 108 are 0.85.BD optical recording media 109a has the substrate that thickness is 0.1mm.
The light that calibration mirror 102 sends semiconductor laser 101 is converted to substantially parallel light.The light by calibration mirror 102 has been incident on the polarization electron beam splitter 103 and by deviation prism 105 deflections.1/4 ripple plate 106 is converted to round polarized light with light, and by aberration correction element 107 and object lens 108 light is compressed on BD optical recording media 109a, thereby carries out recording of information and regeneration.By behind the 1/4 ripple plate 106, be converted into the linearly polarized photon that hangs down as for the polarisation of light direction on the passage forwardly from the emission light of BD optical recording media 109a.Light is reflected, separates, guides to light receiving element 112 by 103 deflections of polarization electron beam splitter and by detecting mirror 110 from incident light.The result detects regenerated signal, focus error signal and trail-and-error signal.
This optical pick-up has two wavelength laser unit 120, generates laser beam that is used for DVD optical recording media 109b and the laser beam that is used for CD optical recording media 109c.In other words, optical pick-up can send the different laser beam of wavelength each other.
From DVD semiconductor laser 113a send have centre wavelength be 660nm to the light of DVD optical recording media 109b through calibration mirror 115 with wavelength is selected electron beam splitter 104 and by deviation prism 105 deflections.By 1/4 ripple plate 106, aberration correction element 107 and object lens 108 light is compressed on the DVD optical recording media 109b then.The substrate thickness of DVD optical recording media 109b is 0.6mm, and several holes (NA) of object lens 108 are 0.65.The switching of aberration correction element 107 restriction NA.After by object lens 108 and 1/4 ripple plate 106, select electron beam splitter 104 deflections by wavelength from the reflected light of DVD optical recording media 109b.Light is separated from incident light and is guided to DVD light receiving element 113c by holographic element 114.The result detects regenerated signal, focus error signal and trail-and-error signal.
From CD semiconductor laser 116a send have centre wavelength be 785nm to the light of CD optical recording media 109c through calibration mirror 115 with wavelength is selected electron beam splitter 104 and by deviation prism 105 deflections.By 1/4 ripple plate 106, aberration correction element 107 and object lens 108 light is compressed on the CD optical recording media 109c then.The substrate thickness of CD optical recording media 109c is 1.2mm, and several holes (NA) of object lens 108 are 0.50.The switching of aberration correction element 107 restriction NA.After by object lens 108 and 1/4 ripple plate 106, select electron beam splitter 104 deflections by wavelength from the reflected light of DVD optical recording media 109b.Light is separated from incident light and is guided to CD light receiving element 116c by holographic element 114.The result detects regenerated signal, focus error signal and trail-and-error signal.
Fig. 6 is the sectional view of the amplification of aberration correction element 107.Fig. 7 A and 7B are the synoptic diagram of the Difraction surface of aberration correction element 107.
Proofread and correct because the compatible elements of the hole limitation function of the spherical aberration that the difference that the NA of substrate thickness and object lens 108 switches is caused by photoconduction in object lens 108 but aberration correction element 107 has, this only has the light to as shown in Figure 5 DVD optical recording media 109b that centre wavelength is 660nm from what DVD semiconductor laser 113a sent.Proofread and correct because the compatible elements of the hole limitation function of the spherical aberration that the difference that the NA of substrate thickness and object lens 108 switches is caused by photoconduction in object lens 108 but aberration correction element 107 also has, this only has the light to CD optical recording media 109c that centre wavelength is 785nm from what CD semiconductor laser 116a sent.
The diffraction region section of aberration correction element 107 comprises a plurality of band concave surfaces and the convex surface section that forms with as shown in Figure 6 concentric shape.The pitch of band concave surface and convex surface section narrows down laterally gradually from the inboard of diffraction region, thereby this diffraction structure has the mirror effect.
Shown in Fig. 7 A and 7B, aberration correction element 107 has the plane section of the outer peripheral areas (second area 151a and 152b) of the circular central region (first area 151a and 152a) that forms diffractive grooves and central area on the electron beam effective diameter.Thereby diffraction region proofreaies and correct beam diffraction by the difference of the substrate thickness of information recording carrier and the spherical aberration that difference of wavelength causes.This diffraction structure is formed on two surfaces of aberration correction element 107.Aberration correction element 107 has different aberration correction functions on each surface.Remaining area is formed on effective diameter between the peripheral diameter as the periphery.
Fig. 8 is the constructed profile of aberration correction element 107 and object lens 108.As shown in Figure 8, aberration correction element 107 and object lens 108 are coaxial integrated by object lens holding member 108b.Especially, aberration correction element 107 is fixed on the end of object lens holding member 108b, and object lens 108 are fixed on the other end, thereby along integrated aberration correction element 107 of light shaft coaxle and object lens 108.
During when recorded information in optical recording media with from the optical recording media regenerating information, object lens 108 with respect to the vertical direction of optical axis according to tracking Control probably ± move in the scope of 0.5mm.Yet, since to the light of DVD optical recording media 109b and CD optical recording media 109c by aberration correction element 107 diffraction, when aberration correction element 107 does not move and when having only object lens 108 to move, aberration and compression point takes place worsen.Therefore, thus aberration correction element 107 and object lens 108 are integrated and move as a whole in tracking Control and obtain satisfied compression point.
107 need of aberration correction element are the elements that the UV resin bed are provided and provide diffraction structure to form at this resin bed by on glass, resin or glass substrate.As the material of aberration correction element 107, resin is suitable, because for glass, and light, the easily moulding and easy production in enormous quantities of weight resin.Expectation is light according to the aberration correction element 107 of the 5th embodiment, is used for focusing on and following the tracks of because aberration correction element 107 moves.The example of resin comprises organic glass (PMMA: the indices of diffraction are respectively 1.51,1.49 and 1.48 when wavelength 405nm, 660nm and 785nm) and Zeonex (registered trademark), and Zeonex is the photopolymer resin that Zeon company makes, and has the high moist feature that absorbs.
As the method for making diffraction structure, when material is glass, only need to make diffraction structure by etching or moulding.When material is resin, only need to make diffraction structure by impression or moulding.
Shown in Fig. 7 A and 7B, be the circle concentric in the surface configuration of the aberration correction element 107 of vertical direction with diffraction region with respect to optical axis.As mentioned above, the advantage that has of the resin of the PMMA that for example uses among the 5th embodiment is that resin can injection moulding.Therefore, resin is to be widely used in optical assembly most, and can easily carry out large batch of production.Yet on the other hand, the moist absorption is the inferior position of resin.This inferior position has not only changed for example light feature of the indices of diffraction and transfer coefficient, and shows as distortion.By aberration correction element 107 is formed and diffraction region and plane domain between borderline phase with circle, it is unitized to absorb the alteration of form that causes owing to PMMA is moist.Therefore, can reduce undulatory property and the optical pickup unit of high precision is provided.Circle comprises polygon.When forming sexangle, aberration correction element 107 can obtain identical effect.When the outer shape of aberration correction element 107 had diameter than light beam effective diameter big 30%, the aberration correction element formed circle or polygon.When outer shape was bigger, aberration correction element 107 can form square.
Above-described compatible optical adapter record the information in for example use the Different Light wavelength in three kinds of optical recording medias (BD, DVD and CD recording medium) in the different numbers hole (NA) of single object lens 108 and from these three kinds of optical recording media regenerating informations.Yet the compatible optical adapter can record the information in the four kinds of optical recording medias (BD, HD, DVD and CD recording medium) with different effectively pupil radiuses and from these four kinds of optical recording media regenerating informations.
Aberration correction element 107 is that four kinds of optical recording medias are proofreaied and correct aberration.Aberration correction unit 107 has the aberration correction function of the DVD that is used on a Difraction surface shown in Figure 6 and CD optical recording media and is used for aberration correction function at the HD of another Difraction surface optical recording media.
Aberration correction element (diffractive optical element) has identical with the said elements structure at the lip-deep meticulous coaxial and concentric diffraction structure of plane component.This diffraction structure is formed on two surfaces of aberration correction element (diffractive optical element).Each surface has different diffraction structures and aberration correction function corresponding to the standard of Different Light wavelength and different optical recording medias.Therefore, be difficult to from visually discerning the textural difference of aberration correction element front-end and back-end.Yet,, can prevent from the front-end and back-end of element are connected instead, and obtain suitable aberration correction function by forming the shape of diffractive optical element in this way.
In structure, use optical pick-up and the total element of diffractive optical element (aberration correction element) in the past, except diffractive optical element being connected to the method for object lens holding member according to the 5th embodiment.Therefore, in the description about structure, the element relevant with this embodiment only described below.
At first, detailed description is according to the outer shape of the aberration correction element of the 5th embodiment.Shown in Fig. 6, Fig. 7 A and 7B, the lip-deep diffraction structure that is formed on aberration correction element 107 has meticulous band shape.Be difficult to from visually discerning the textural difference of aberration correction element 107 front-end and back-end.Yet this diffraction structure has different aberration correction functions on each surface.Therefore, when the front-end and back-end of aberration correction unit are not connected to correct direction, just can not get suitable aberration correction function.In the component shape in the past, the outer shape of aberration correction element 107 is cylindrical, the thickness direction symmetry of outer peripheral end and first and second Difraction surface 151 and 152.Therefore, can cause connection error to take place owing to connect anti-front-end and back-end with respect to object lens holding member 108b.
As first example of the 5th embodiment, shown in Fig. 9 A, the outer shape of aberration correction element 107 be on the outer peripheral end place of aberration correction element 107 first Difraction surface 151 and second Difraction surface 152 on asymmetrical shape.The diffraction region that has with respect to the aberration correction function of the optical axis of object lens 108 forms circular concentric.Yet, as aberration correction element 107 other regional outer peripheral end, the second Difraction surface overall diameter 162 is set to bigger than the first Difraction surface overall diameter 161, the outer peripheral end of first Difraction surface 151 forms the classification shape, protrudes to inside from the outside.
First Difraction surface 151 has the overall diameter (the first Difraction surface overall diameter 161) of the opening that is equal to or less than object lens holding member 108b.Second Difraction surface 152 has greater than the overall diameter of the opening of object lens holding member 108b (the second Difraction surface overall diameter 162).Thereby when the front-end and back-end of aberration correction element 107 connected instead to object lens holding member 108b, aberration correction element 107 can not correctly be fixed.Therefore, the front-end and back-end that can prevent aberration correction element 107 are connected instead.Shown in Fig. 9 B, if can guarantee to have the zone of aberration correction function, the outer shape of object lens holding member 108b and aberration correction element can be a square.
As second example of the 5th embodiment, shown in Figure 10 A and 10B, the outer shape of aberration correction element 107 on first Difraction surface 151 and second Difraction surface 152 on asymmetric.The diffraction region that has with respect to the aberration correction function of the optical axis of object lens 108 forms circular concentric.As in first example, outer peripheral end at aberration correction element 107, the second Difraction surface overall diameter 162 is set to bigger than the first Difraction surface overall diameter 161, the outer peripheral end of first Difraction surface 151 forms taper, protrude when the opening of object lens holding member 108b tilts with the same manner from the periphery to inside, if the front-end and back-end of object lens holding member 108b connect anti-, object lens holding member 108b just can not correctly fix.Therefore, can prevent from front-end and back-end are connected instead.
When the plane component that for example used according to the aberration correction element 107 of the 5th embodiment, must consider flash of light.The not transmission of the incidence surface by optical assembly and change into regular reflection light of 108 part light from light source to object lens.When aberration correction element 107 is arranged to the vertical incidence light time, shown in Figure 11 A, regular reflection light may cover the reflected light from optical recording media 109, i.e. flashlight, and change into noise light.In order to handle this problem, it is plane of incidence on the slight inclination optical assembly that a kind of method is arranged.Can prevent that by inclination aberration correction element 107 shown in Figure 11 B the regular reflection optical superposition is on flashlight.
As the 3rd example of the 5th embodiment, shown in Figure 12 A and 12B and Figure 13 A and 13B, that describes in the outer shape of aberration correction element 107 and first and second example is similar, has only the surface that the forms diffraction structure inclined light shaft with respect to object lens 108.Therefore, be connected to that object lens holding member 108b goes up and the regular reflection optical superposition to flashlight the time, can not prevented to connect the front-end and back-end of aberration correction element 107 anti-when aberration correction element 107.
The regulator and the optical information processing apparatus that comprise diffractive optical element (aberration correction element) as sixth embodiment of the invention are described below.Figure 14 has shown the schematic construction of the regulator of optical pick-up.The regulator of optical pick-up comprises object lens 108 and keeps the object lens holding member 108b of object lens 108.The regulator of optical pick-up also comprise the base unit 125 of supporting object lens holding member 108 and be inserted in base unit 125 and object lens holding member 108b between elasticity supporting mechanism 126 and 127.Thereby elasticity supporting mechanism 126 and 127 flexibly supports object lens holding member 108b to allow object lens holding member 108b to move at both direction with respect to pedestal 125, i.e. focus direction and tracking direction.Focus direction refers to the Z-direction (optical axis directions of object lens 108) among Figure 14 and tracking direction refers to the X-direction (radial direction of optical recording media 109) among Figure 14.
The regulator of optical pick-up comprises driver element (figure does not show).This driver element comprises voice loop motor (comprising the permanent magnet that is provided on the object lens holding member 108b) and the drive coil of fixing with respect to base unit 125.Driver element drives object lens holding member 108b according to the input current to drive coil at both direction.The input current of drive coil that is controlled to driver element to be to carry out focus servo and tracking servo, and the record that makes predetermined laser beam spot follow on the information recording surface of optical recording media 109 is followed the tracks of.
Figure 15 is the block diagram of optical information processing apparatus.Optical information processing apparatus uses according to the optical pick-up with diffractive optical element of the 5th embodiment and one of carries out in information regeneration, information record and the information erasing with respect to optical recording media at least.
Optical information processing apparatus comprises the optical pick-up 91 that is equal to above-mentioned optical pick-up.Optical information processing apparatus further comprises the Spindle Motor 98 that drives optical recording media 109 rotations, the optical pick-up 91 that uses in the record of execution information signal and the regeneration, optical pick-up 91 is moved to the feeding motor 92 of optical recording media 109 inner peripheral, carry out predetermined modulation and conciliate the modulating/demodulating system circuit 94 of modulation treatment, the servo control circuit 93 of the servocontrol of execution optical pick-up 91 etc. and execution are to the system controller 96 of the control of overall optical messaging device.
Control Spindle Motor 98 is driven by servo control circuit 93 and rotates with predetermined number of revolutions.As the optical recording media 109 of record and regeneration target by chuck on the drive shaft rod of Spindle Motor 98 and Be Controlled drive by servo control circuit 93.Optical recording media 109 is driven by Spindle Motor 98 and rotates with predetermined number of revolutions.
When information signal recording during at optical recording media 109 or from optical recording media 109 regeneration, as mentioned above, the back light of optical pick-up 91 illuminating laser beam and detection laser beam on the optical recording media 109 that is driven in rotation.Optical pick-up 91 is connected on the modulating/demodulating system circuit 94.When recording information signal, the signal input of handling through the predetermined modulation of modulating/demodulating system circuit 94 from external circuit 95 is provided to optical pick-up 91.The signal that optical pick-up 91 provides based on modulating/demodulating system circuit 94 will be through the laser beam irradiation of light intensity modulation on optical recording media 109.When the regenerating information signal, optical pick-up 91 with the laser beam irradiation of constant power on the optical recording media 109 that is driven in rotation.Generate regenerated signal and this regenerated signal is offered modulating/demodulating system circuit 94 from the back light of laser beam.
Optical pick-up 91 also is connected on the servo control circuit 93.When record and regenerating information signal, as mentioned above, generate focus servo signal and tracking servo signal from optical recording media 109 reflections that are driven in rotation and the back light that returns optical pick-up 91.Servosignal is provided for servo control circuit 93.
Modulating/demodulating system circuit 94 is connected to system controller 96 and external circuit 95.When information signal was recorded in the optical recording media 109, modulating/demodulating system circuit 94 received the signal that will be recorded in the optical recording media 109 and handles to this signal application predetermined modulation under the control of system controller 96 from external circuit 95.
The signal of modulating/demodulating system circuit 94 modulation is offered optical pick-up 91.When from optical recording media 109 regenerating information signals, modulating/demodulating system circuit 94 receives from the regenerated signal of optical recording media 109 regeneration and under the control of system controller 96 from optical pick-up 91 and uses predetermined rectification processing to this regenerated signal.Export the signal of modulating by modulating/demodulating system circuit 94 to external circuit 95 from modulating/demodulating system circuit 94.
Feeding motor 92 is the motors that in the radial direction of optical recording media 109 optical pick-up 91 moved to the precalculated position when the record of carrying out information signal and regeneration the time.Drive feeding motor 92 based on control signal from servo control circuit 93.Feeding motor 92 is connected to servo control circuit 93 and is controlled by servo control circuit 93.
Under the control of system controller 96, servo control circuit 93 control feeding motors 92 move to precalculated position with respect to optical recording media 109 with optical pick-up 91.Servo control circuit 93 also is connected to Spindle Motor 98 and controls the operation of Spindle Motor 98 under the control of system controller 96.When information signal recording during in optical recording media 109 or from information recording carrier 109 regeneration, servo control circuit 93 control Spindle Motors 98 are with predetermined number of revolutions driven in rotation optical recording media 109.
Can use tracking servo signal and focus servo signal method as the type of resolved light recording medium 109.By in multiple optical recording medium information with optical pick-up according to the embodiment of the invention is provided, can improve in optical recording media 109 recorded information and from the accuracy of its regenerating information with substrates of different thickness from the optical information processing apparatus of their regenerating informations.
As mentioned above, according to the 6th embodiment, when aberration correction element (diffractive optical element) 107 is connected to the object lens holding member 108b that is used for objective lens actuator, optical pick-up and optical information processing apparatus, can prevent that thereby the front-end and back-end of aberration correction element 107 are connected anti-and single object lens is formed on polytype optical recording media with substrates of different thickness (BD for example, HD, DVD and CD optical recording media) lip-deep suitable point.Also can obtain suitable aberration correction function and be used on optical recording media, implementing optimum record, regeneration and erasure information Signal Processing.
According to diffractive optical element and objective lens actuator, the optical pick-up of the embodiment of the invention with comprise in the optical information processing apparatus of diffractive optical element, the outer shape of diffractive optical element forms that to make that the front-end and back-end that can not say diffraction Guangyuan part connect anti-.According to diffractive optical element and objective lens actuator, the optical pick-up of the embodiment of the invention with comprise in the optical information processing apparatus of diffractive optical element, the outer shape of diffractive optical element forms that to make that the front-end and back-end that can not say diffraction Guangyuan part connect anti-.In the manufacture process of diffractive optical element, can prevent from the front-end and back-end of diffractive optical element are connected anti-to object lens and obtain suitable aberration correction function.Diffractive optical element and objective lens actuator, optical pick-up and optical information processing apparatus have three kinds of different recording density as processing or the compatible equipment of more eurypalynous optical recording media is useful.
Figure 16 is the fragmentary cross-sectional view according to the object lens fixture of the objective lens actuator that is used for optical pick-up of seventh embodiment of the invention.In object lens fixture 201 as shell, object lens 202 are provided on top, diffractive optical element 203 is provided in the bottom.
Object lens 202 are gone up compression light beam to form light beam spot at the CD (figure does not show) as optical information recording medium.Diffractive optical element 203 makes can compatibility (following will the detailed description in detail) corresponding to the CD of three or multiple disk standard of the light beam of at least three kinds of wavelength.
In the 7th embodiment, optical axis by diffractive optical element 203 is set to the inclined light shaft with respect to object lens 202, and object lens 202 and diffractive optical element 203 are provided, locate and be fixed in the single object lens fixture 201, the regulator with little and light removable unit of light can be provided.In addition, can prevent to disturb owing to the inclined light shaft with respect to object lens 202 connects the light that regular reflection that diffractive optical element 203 brings causes.
In this embodiment, on the contact side of the upside of the downside of object lens fixture 201 and flange section 203a, three points or three zonules are provided with necessary inclination.Especially, as shown in figure 16, provide three types protuberance 213 highlightedly at the downside of object lens fixture 201, protuberance 213 is set to contact with the planar side of the upside of flange section 203a.Protuberance 213 on the front end does not show in Figure 16.
Protuberance 213 and be not limited to said structure corresponding to the plane surface of protuberance 213.It is exactly enough protuberance 213 being provided in one of object lens fixture 201 and diffractive optical element 203 and forming plane surface on another.
In this embodiment, need separately execution to the aligning of optical axis.Yet for example reference light transmitting beam feature is regulated the optical axis that is registered to object lens 202 with the optical axis at the center of the optical surface of object lens side in the diffractive optical element 203.
After regulating, use the bonding welding process of known for example ultraviolet curing that object lens fixture 201 and flange section 203a are welded.
Figure 17 is the fragmentary cross-sectional view according to the object lens fixture of the objective lens actuator of eighth embodiment of the invention.
In the 8th embodiment, three positions of the object lens 202 in object lens fixture 201 provide hemisphere recess 214, and these three positions distribute every 120 degree along its optical axis.Relevant with recess 214, three hemisphere protuberances 215 are provided in flange section 203a.Recess 214 and protuberance 215 are contacted with each other so that relative position and inclination to be set.Recess 214 and protuberance 215 on the front end do not show in Figure 17.
In the 8th embodiment, three protuberances 215 of flange section 203a are arranged on the height identical with respect to the reference surface of diffractive optical element 203.When reference surface tilts with the position of the recess 214 of object lens fixture 201 sides and depth adjustment position to protuberance 215.Therefore, can carry out the location of diffractive optical element 203 exactly and, need not provide structure with respect to the inclined light shaft of object lens 202 with respect to the adjusting of the inclination of object lens 202.
Figure 18 is the fragmentary cross-sectional view according to the object lens fixture of the objective lens actuator of ninth embodiment of the invention.The difference of the 9th embodiment and the 8th embodiment is to be arranged to the position of recess 214 and protuberance 215 opposite.In the 9th embodiment, three positions of the object lens 202 in object lens fixture 201 provide hemisphere protuberance 215, and these three positions distribute every 120 degree along its optical axis.Relevant with protuberance 215, three hemisphere recesses 214 are provided in flange section 203a.Recess 214 and protuberance 215 are contacted with each other so that relative position and inclination to be set.
In the 9th embodiment, three recesses 214 of flange section 203a are arranged on the height identical with respect to the reference surface of diffractive optical element 203.When reference surface tilts with the position of the protuberance 215 of object lens fixture 201 sides and depth adjustment position to recess 214.Therefore, can carry out the location of diffractive optical element 203 exactly and, need not provide structure with respect to the inclined light shaft of object lens 202 with respect to the adjusting of the inclination of object lens 202.
Figure 19 is the fragmentary cross-sectional view according to the object lens fixture of the objective lens actuator of tenth embodiment of the invention.In the tenth embodiment, three positions of the object lens 202 in object lens fixture 201 provide tapered recess 216, and these three positions distribute every 120 degree along its optical axis.Relevant with recess 216, three hemisphere protuberances 217 are provided in flange section 203a.Recess 216 and protuberance 217 are contacted with each other so that relative position and inclination to be set.Recess 216 and protuberance 217 on the front end do not show in Figure 17.
In the tenth embodiment, three protuberances 217 of flange section 203a are arranged on the height identical with respect to the reference surface of diffractive optical element 203.When reference surface tilts with the position of the recess 216 of object lens fixture 201 sides and depth adjustment position to protuberance 217.Therefore, can carry out the location of diffractive optical element 203 exactly and, need not provide structure with respect to the inclined light shaft of object lens 202 with respect to the adjusting of the inclination of object lens 202.
Figure 20 is the fragmentary cross-sectional view according to the object lens fixture of the objective lens actuator of eleventh embodiment of the invention.The difference of the 11 embodiment and the tenth embodiment is to be arranged to the position of recess 216 and protuberance 217 opposite.In the 11 embodiment, three positions of the object lens 202 in object lens fixture 201 provide hemisphere protuberance 217, and these three positions distribute every 120 degree along its optical axis.Relevant with protuberance 217, three tapered recess 216 are provided in flange section 203a.Recess 216 and protuberance 217 are contacted with each other so that relative position and inclination to be set.
In the 11 embodiment, three recesses 216 of flange section 203a are arranged on the height identical with respect to the reference surface of diffractive optical element 203.When reference surface tilts with the position of the protuberance 217 of object lens fixture 201 sides and depth adjustment position to recess 216.Therefore, can carry out the location of diffractive optical element 203 exactly and, need not provide structure with respect to the inclined light shaft of object lens 202 with respect to the adjusting of the inclination of object lens 202.
Figure 21 A is the sectional view according to the object lens fixture of the objective lens actuator of twelveth embodiment of the invention.Figure 21 B is its backplan.In the 12 embodiment, three positions of the object lens 202 in object lens fixture 201 provide the V-arrangement recess 218 of the axis of symmetry with the optical axis of striding object lens 202, and these three positions distribute every 120 degree along its optical axis.Relevant with recess 218, three hemisphere protuberances 219 are provided in the lower casing 212 of diffractive optical element 203.Recess 218 and protuberance 219 are contacted with each other so that relative position and inclination to be set.
In the 12 embodiment, three protuberances 219 of flange section 203a are arranged on the height identical with respect to the reference surface of diffractive optical element 203.When reference surface tilts with the position of the recess 218 of object lens fixture 201 sides and depth adjustment position to protuberance 219.Therefore, can carry out the location of diffractive optical element 203 exactly and, need not provide structure with respect to the inclined light shaft of object lens 202 with respect to the adjusting of the inclination of object lens 202.
Figure 22 is the fragmentary cross-sectional view according to the object lens fixture of the objective lens actuator of thriteenth embodiment of the invention.The difference of the 13 embodiment and the 12 embodiment is to be arranged to the position of recess 218 and protuberance 219 opposite.In the 13 embodiment, three positions of the object lens 202 in object lens fixture 201 provide V-arrangement recess 218, and these three positions distribute every 120 degree along its optical axis.Relevant with recess 218, provide three hemisphere protuberances 219 in the lower casing 212 of diffractive optical element 203.Recess 218 and protuberance 219 are contacted with each other so that relative position and inclination to be set.
In the 13 embodiment, three recesses 218 of flange section 203a are arranged on the height identical with respect to the reference surface of diffractive optical element 203.When reference surface tilts with the position of the protuberance 219 of object lens fixture 201 sides and depth adjustment position to recess 218.Therefore, can carry out the location of diffractive optical element 203 exactly and, need not provide structure with respect to the inclined light shaft of object lens 202 with respect to the adjusting of the inclination of object lens 202.
Figure 23 is the fragmentary cross-sectional view according to the object lens fixture of the objective lens actuator of fourteenth embodiment of the invention.In the 14 embodiment, with high-end the contacting with each other of the low side and the flange section 203a of object lens fixture 201.Contact jaw at object lens fixture 201 and flange section 203a provides the recess 220 with the shape (radius of sphericity is R) that forms the part spheroid, and the center of this shape is near the lip-deep center O of the object lens 202 on the optical axis of diffractive optical element 203.Relevant with recess 220, provide protuberance 221 at protuberance 221 at the contact jaw of object lens fixture 201 and flange section 203a with the shape that also forms the part spheroid, the center of this shape is near lip-deep center O.Recess 220 and protuberance 221 are contacted with each other so that relative position and inclination to be set.
Although Figure 23 does not show tilt adjustment mechanism, fixedly object lens fixture 201 and flange section 203a after adjusting.Alternatively, can protuberance be provided and protuberance contact inclination and holding flange section 203a with definite flange section 203a with object lens fixture 201 at the flange section 203a that tilts.Therefore, can carry out the location of diffractive optical element 203 exactly and, need not provide structure with respect to the inclined light shaft of object lens 202 with respect to the adjusting of the inclination of object lens 202.
Figure 24 is the fragmentary cross-sectional view according to the object lens fixture of the objective lens actuator of fifteenth embodiment of the invention.The 15 embodiment and the 14 embodiment something in common are high-end the contacting with each other of the low side and the flange section 203a of object lens fixture 201.Contact jaw at object lens fixture 201 and flange section 203a provides the protuberance 221 with the shape (radius of sphericity is R) that forms the part spheroid, and the center of this shape is near the lip-deep center O of the object lens 202 on the optical axis of diffractive optical element 203.Flange section 203a is set to form the conical surfaces 222 relevant with protuberance 221 at the contact jaw of object lens fixture 201.Protuberance 221 and surface 222 are contacted with each other so that relative position to be set.
Although Figure 24 does not show tilt adjustment mechanism, fixedly object lens fixture 201 and flange section 203a after adjusting.Alternatively, can protuberance be provided and protuberance contact inclination and holding flange section 203a with definite flange section 203a with object lens fixture 201 at the flange section 203a that tilts.Therefore, can carry out the location of diffractive optical element 203 exactly and, need not provide structure with respect to the inclined light shaft of object lens 202 with respect to the adjusting of the inclination of object lens 202.
Figure 25 is the fragmentary cross-sectional view according to the object lens fixture of the objective lens actuator of sixteenth embodiment of the invention.In the 16 embodiment, in object lens fixture 201, form groove 223 with width identical with the diameter of the outer cylinder surface of flange section 203a with the symmetrical of object lens 202 ground.The outer cylinder surface of flange section 203a is fit to this groove 223.
Protuberance 224 with cylindrical shape laterally is provided on the outer cylinder surface of flange section 203a, and this cylindrical shape has the central shaft on the axle of the center O on the surface of object lens 202 sides of passing through diffractive optical element 203.Hang down as for form groove 223 within the walls the direction of groove 223, protuberance 224 rectangular recess 225 relevant that be fit to provide with protuberance 224.
According to this structure, in the 16 embodiment, in hanging down as for the plane of the optical axis of object lens 202 can both direction carry out to the location of optical axis and by with element around the cylinder protuberance 224 rotations diffractive optical element 203 that tilts.
Although Figure 25 does not show tilt adjustment mechanism, fixedly object lens fixture 201 and flange section 203a after adjusting.Alternatively, can protuberance be provided and protuberance contact inclination and holding flange section 203a with definite flange section 203a with object lens fixture 201 at the flange section 203a that tilts.Therefore, can carry out the location of diffractive optical element 203 exactly and, need not provide structure with respect to the inclined light shaft of object lens 202 with respect to the adjusting of the inclination of object lens 202.
Figure 26 is the fragmentary cross-sectional view according to the object lens fixture of the objective lens actuator of seventeenth embodiment of the invention.The difference of the 17 embodiment and the 16 embodiment only is that the rectangular recess 225 among the 16 embodiment has just become v-depression 226.Therefore, as in the 16 embodiment, can carry out the location of diffractive optical element 203 exactly and, need not provide structure with respect to the inclined light shaft of object lens 202 with respect to the adjusting of the inclination of object lens 202.
Figure 27 is the synoptic diagram according to the optical pick-up device that objective lens actuator is installed of embodiment.Optical pick-up device be record the information in for example use the Different Light wavelength in three kinds of optical recording medias (BD, DVD and CD recording medium) in the different numbers hole (NA) of single object lens 202 and from the compatible optical adapter of these three kinds of optical recording media regenerating informations.Just do not repeated about the identical description of Fig. 5 with above-mentioned.
In the 18th embodiment of the present invention, optical recording/reproducing apparatus comprises the optical pick-up that is equal to optical pick-up device shown in Figure 27.Be equipped with optical pick-up optical recording/reproducing apparatus structure basically with Fig. 5 in describe identical.Therefore, just do not repeat identical description at this.
Have the optical pick-up according to the embodiment of the invention, optical recording/reclaim equiment can record the information in to high precision in the polytype optical recording media with substrates of different thickness and from these optical recording media regenerating informations.
Clearly describe although the present invention has been carried out complete sum, do not limit claim of the present invention with reference to specific embodiment.In the scope of basic teaching of the present invention, those of ordinary skills can carry out various modification and alternative constructions.

Claims (19)

1. objective lens actuator comprises:
Object lens fixture remains on the first surface side with object lens;
Drive coil is provided in the object lens fixture and generation focuses on thrust and follows the tracks of thrust;
Elastic supporting member is flexibly supported object lens fixture according to the thrust amount that drive coil produces;
Diffractive optical element, be positioned at object lens light incident side, outgoing laser beam and and the reflected signal compatibility of laser beam; And
The inertia ballast is positioned at object lens fixture second surface side, wherein
Object lens and diffractive optical element directly are fixed on the object lens fixture.
2. objective lens actuator according to claim 1, wherein diffractive optical element is positioned at the second surface side of object lens fixture.
3. objective lens actuator according to claim 1, wherein diffractive optical element is formed from a resin.
4. objective lens actuator according to claim 1, wherein the inertia ballast is made by sheet metal.
5. objective lens actuator according to claim 1, wherein the inertia ballast covers except the whole second surface corresponding to the extra-regional object lens fixture of diffractive optical element.
6. diffractive optical element is supported corresponding to the compatibility between the optical recording media of three kinds of various criterions of the light source of three kinds of different wave lengths, wherein at least at least
Diffractive optical element is concentric diffraction, and described diffractive optical element comprises:
First surface and second surface, each surface all comprise the aberration correction zone that corresponds respectively to different wave length and various criterion; With
First outer peripheral areas on the first surface and second outer peripheral areas on the second surface, first outer peripheral areas and second outer peripheral areas are that appearance is asymmetrical.
7. diffractive optical element according to claim 6, wherein any of first outer peripheral areas and second outer peripheral areas all protruded from the outside to internal classification.
8. diffractive optical element according to claim 6, wherein any of first outer peripheral areas and second outer peripheral areas all is to the interior tapered convergent from the outside.
9. diffractive optical element according to claim 6, wherein the shape of first outer peripheral areas and second outer peripheral areas is to make the optical axis in aberration correction zone with respect to the shape of the inclined light shaft predetermined angular of object lens.
10. an objective lens actuator comprises diffractive optical element according to claim 6.
11. an optical pick-up device comprises diffractive optical element according to claim 6.
12. objective lens actuator according to claim 1, wherein
Diffractive optical element support corresponding to the compatibility between the optical recording media of a plurality of standards of the light source of a plurality of different wave lengths and
Diffractive optical element is arranged so that the inclined light shaft of the optical axis of diffractive optical element with respect to object lens.
13. objective lens actuator according to claim 12, wherein
Any of object lens fixture and diffractive optical element comprises protuberance, and this protuberance has the shape of semisphere or three positions formation part spheroids around the optical axis of object lens,
Another of object lens fixture and diffractive optical element comprise corresponding to the hemispherical concave depressions of protuberance and
Protuberance and recess are located diffractive optical element with respect to the optical axis of object lens.
14. objective lens actuator according to claim 12, wherein
Any of object lens fixture and diffractive optical element comprises protuberance, and this protuberance has the shape of semisphere or three positions formation part spheroids around the optical axis of object lens,
Another of object lens fixture and diffractive optical element comprise corresponding to the tapered recess of protuberance and
Protuberance and recess are located diffractive optical element with respect to the optical axis of object lens.
15. objective lens actuator according to claim 12, wherein
Any of object lens fixture and diffractive optical element comprises protuberance, and this protuberance has the shape of semisphere or three positions formation part spheroids around the optical axis of object lens,
Another of object lens fixture and diffractive optical element be included in hang down as for the direction of the optical axis of object lens corresponding to the section V-arrangement recess of protuberance and
Protuberance and recess are located diffractive optical element with respect to the optical axis of object lens.
16. objective lens actuator according to claim 12, wherein
Object lens fixture comprises first contact portion,
Diffractive optical element comprises second contact portion that contacts with first contact portion,
Second contact portion comprises spherical protuberance, and this sphere protuberance has the center of the centre of surface of the object lens side on the optical axis of close diffractive optical element,
First contact portion comprise corresponding to the recess of protuberance and
Protuberance and recess are with respect to the optical axis of object lens and regulate the position of diffractive optical element.
17. objective lens actuator according to claim 12, wherein
Object lens fixture comprises first contact portion,
Diffractive optical element comprises second contact portion that contacts with first contact portion,
Second contact portion comprises spherical protuberance, and this sphere protuberance has the center of the centre of surface of the object lens side on the optical axis of close diffractive optical element,
First contact portion comprise corresponding to the surface of protuberance and
The position of diffractive optical element is regulated on protuberance and surface with respect to the optical axis of object lens.
18. objective lens actuator according to claim 12, wherein
Object lens fixture and diffractive optical element be arbitrary to include horizontal cylinder protuberance, and this horizontal cylinder protuberance has the central shaft of the centre of surface of the object lens side on the optical axis of close diffractive optical element,
Another of object lens fixture and diffractive optical element be included in objective lens optical axis intersect direction corresponding to the section rectangular recess of protuberance and
Protuberance and groove are with respect to the optical axis of object lens and diffractive optical element is located.
19. objective lens actuator according to claim 12, wherein
Object lens fixture and diffractive optical element be arbitrary to include horizontal cylinder protuberance, and this horizontal cylinder protuberance has the central shaft of the centre of surface of the object lens side on the optical axis of close diffractive optical element,
Another of object lens fixture and diffractive optical element be included in objective lens optical axis intersect direction corresponding to the section v-depression of protuberance and
Protuberance and groove are with respect to the optical axis of object lens and diffractive optical element is located.
CNA2007101533605A 2006-09-19 2007-09-18 Objective lens actuator, diffractive optical element, and optical pickup device Pending CN101149938A (en)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
JP2006253053 2006-09-19
JP2006253053A JP2008077708A (en) 2006-09-19 2006-09-19 Objective lens actuator
JP2006310093 2006-11-16
JP2006316732 2006-11-24
JP2006353594 2006-12-28

Publications (1)

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CN101149938A true CN101149938A (en) 2008-03-26

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CNA2007101533605A Pending CN101149938A (en) 2006-09-19 2007-09-18 Objective lens actuator, diffractive optical element, and optical pickup device

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CN (1) CN101149938A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102024475A (en) * 2009-09-14 2011-04-20 三星电子株式会社 Optical pickup apparatus having multi-sectional polarizer

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102024475A (en) * 2009-09-14 2011-04-20 三星电子株式会社 Optical pickup apparatus having multi-sectional polarizer

Also Published As

Publication number Publication date
JP2008077708A (en) 2008-04-03

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