CN1755829B - Optical pick-up apparatus and lens unit therefor, lens frame for lens unit, assembly method of the lens unit - Google Patents

Abstract

A lens unit for a light picker is provided with an objective lens for converging the emergent light coming from a light source to an information recording surface of a light information recording medium; a phase control element of an optical surface, which is provided with a phase structure controlling the phase of the emergent light coming from the light source and is arranged at the light source side corresponding to the objective lens; and a supporting component for supporting the objective lens and the phase control element, wherein, the phase control element prescribes the angle according to the optical axis inclination of the objective lens corresponding to an optical axis of the phase control element; moreover, the junction of the optical axis of the phase control element and the optical surface with the phase structure is kept by the state arranged on the central prolonged optical length of the optical axis of the objective lens.

Description

Optical Pickup device and lens unit thereof, lens unit are with picture frame and assembly method

Technical field

The optical elements such as object lens that the present invention relates in the optical head that light picker is used to be assembled, the optical Pickup device be made up of a plurality of optical elements such as these object lens are with lens unit, lens unit assembly method and this optical Pickup device with picture frame, lens unit.

Background technology

Up to now, be used for the optical information recording medium of CD (CD), DVD (Digital video disc) etc. is carried out the regeneration of information and/or the exploitation of various light pickers (opticalpickup) device quilt, the manufacturing and general universal of record.(optical read/write head: device optical head) exists the object lens body is fixed in retainer with phase control element and integrated so that CD and DVD both sides stablize the way that writes down, regenerates as the optical head of in this optical Pickup device, being assembled.At this moment, on object lens body and phase control element, be provided with respectively central shaft to the telltale mark that share to prevent off-centre and to realize the attenuating (with reference to patent documentation 1) of corrugated aberration.

[patent documentation 1] Jap.P. Publication Laid-Open 2001-6203 communique

But the off-centre of the optic probe device as above-mentioned prevents method, object lens body and the prerequisite of aiming at of phase control element be both very near being configured, both are overstepping the bounds of propriety from just decline more of alignment precision.In addition, above-mentioned off-centre prevents that method from so that the optical axis of above-mentioned object lens body and the optical axis of position control component are remained basic prerequisite abreast, under the situation that both tilt, just having the possibility that alignment precision is low or aberration takes place.

In addition, can see also that recently object lens body and phase control element as above-mentioned is through directly or indirect joint the and as through incorporate lens unit, be assembled into the situation in the optic probe device.Lens unit like this carries out under the situation of instrumentation to imaging characteristic; For example utilize interferometer to carry out instrumentation, but when this instrumentation, make the situation that interference fringe (interference fringe) is disorderly or its contrast low, the instrumentation precision reduces with regard to having because of back light from phase control element.

In addition, when the optical Pickup device of such lens unit has been assembled in use, also there is back light from phase control element to incide photodetector and brings dysgenic worry equally with above-mentioned.

And then; Recently; BD of densification (Blu-ray) or HD (HD DVD) optical Pickup device that is is developed more, and have to the exchange type corresponding with DVD and BD or DVD and HD, or with the needs of the object lens of the corresponding 3 wavelength exchange type of CD, DVD and BD or CD, DVD and HD.In this object lens; Generally speaking have by means of phase control element and will give formation with respect to BD or HD for the interchangeability of CD, DVD or CD and DVD through the object lens body of aberration correction; So for the position of the object lens body of phase control element or inclination, particularly; Just bring significant impact for the displacement of the object lens body that makes the formed phase structure of phase control element is eccentric, so on the aligning of phase control element, just require several microns precision to the DVD system of long wavelength side or the imaging characteristic of CD system.

Summary of the invention

Problem of the present invention is considered the problems referred to above, is distance or the mutual inclination of optical axis lens unit that both alignment precisions are improved simply between phase control object lens body and the phase control element no matter purpose provides a kind of.

And a kind of lens unit that the imaging characteristic that exchanges the type object lens is improved simply just can be provided as a result of.

In addition, the objective of the invention is in object lens body and the incorporate lens unit of phase control element, to prevent generation from the back light of phase control element, and the instrumentation that makes imaging characteristic high precision int simply.

The purpose of this invention is to provide a kind ofly when the use of optical Pickup device in addition, also can prevent the dysgenic lens unit that causes because of back light photodetector from phase control element.

In addition, the purpose of this invention is to provide and a kind ofly can make the lens unit that the imaging characteristic corresponding to the exchange type object lens of BD or HD is improved simply and do not make assembly process complicated.

In addition, the purpose of this invention is to provide a kind of assembly method that is suitable for obtaining optical element, picture frame and the lens unit of said lens unit.

In addition, the high-precision optical Pickup device that the purpose of this invention is to provide a kind of lens unit as above-mentioned of having packed into.

Above-mentioned purpose of the present invention is achieved through following technical scheme of the present invention.

(1) a kind of optical Pickup device is used lens unit, it is characterized in that, comprising:

Object lens are configured in the optical information recording medium side and have the 1st intrinsic optical axis;

Phase control element is configured in light source side and holds the 2nd intrinsic optical axis and have opposed two optical surfaces; And

Holding components; Under the state that above-mentioned the 2nd optical axis tilts with ormal weight with respect to above-mentioned the 1st optical axis, the above-mentioned relatively object lens of above-mentioned phase control element are fixed, and be held within two optical surfaces of above-mentioned phase control element, the central point that formed the optical surface of phase structure prolongs the state through aiming on the light path at the center through above-mentioned the 1st optical axis extending.

(2) a kind of optical Pickup device is used optical element, it is characterized in that, comprising:

The 1st optical surface with the 1st phase structure; And

Be arranged on and opposed the 2nd optical surface of going up, having the 2nd phase structure of above-mentioned the 1st optical surface,

The optical axis of the optical axis of above-mentioned the 1st optical surface and above-mentioned the 2nd optical surface is parallel to each other and separates formation with predetermined distance.

(3) a kind of optical Pickup device of a plurality of optical elements that keeps is used picture frame, it is characterized in that, comprising:

The 1st maintaining part has the 1st reference field that position the 1st optical element, optical axis direction is limited and the 1st fitting portion to limiting perpendicular to the position of the direction of optical axis; And

The 2nd maintaining part; Also be provided with, have the 2nd reference field that the position 2nd optical element, optical axis direction different with above-mentioned the 1st optical element limited and the 2nd fitting portion than above-mentioned the 1st maintaining part to limiting perpendicular to the position of the direction of optical axis by light source side

One side of the above-mentioned the 1st and the 2nd reference field forms with respect to the face tilt vertical with optical axis.

(4) a kind of optical Pickup device; Be used to emergent light from light source carry out information to the 1st optical information recording medium with protective substrate thickness t 1 and record and/or the information of each information recording surface of the 2nd optical information recording medium with protective substrate thickness t 2 from the regeneration of each information recording surface; T1≤t2 wherein; This optical Pickup device is characterised in that, comprising:

Outgoing has the 1st light source of the 1st laser of wavelength X 1;

Outgoing has the 2nd light source of the 2nd laser of wavelength X 2, and wherein λ 1＜λ 2;

Make the object lens of the above-mentioned the 1st and the 2nd laser difference optically focused at the 1st and the 2nd optical information recording medium; And

Above-mentioned relatively object lens are configured in light source side, possess the phase control element of the optical surface with phase structure,

Above-mentioned phase control element, the intersection point that intersects with respect to the inclined light shaft predetermined angular of above-mentioned object lens and optical axis that makes above-mentioned phase control element and the optical surface with above-mentioned phase structure with the optical axis of above-mentioned phase control element prolong the consistent state of light path about the center of the optical axis through above-mentioned object lens and are able to maintenance.

(5) a kind of optical Pickup device is with the assembly method of lens unit; This optical Pickup device has holding components with lens unit; Make emergent light from light source be focused at object lens on the information recording surface of optical information recording medium and the phase control element with the optical surface that forms phase structure, this assembly method is characterised in that:

The 1st step of above-mentioned object lens is installed at above-mentioned holding components;

Above-mentioned phase control element is installed on above-mentioned holding components so that the optical axis of optical surface with above-mentioned phase structure with respect to the 2nd step of the inclined light shaft of above-mentioned object lens;

The phase control element of being installed on the above-mentioned holding components and above-mentioned object lens are carried out the position adjustment, so that the intersection point that the optical axis of the optical surface of the formation phase structure of above-mentioned phase control element and the optical surface with above-mentioned phase structure intersect is about the 3rd consistent step of center prolongation light path of the optical axis extending through above-mentioned object lens;

The 4th step that the above-mentioned relatively holding components of above-mentioned phase control element is fixed; And

The 5th step that the above-mentioned relatively holding components of above-mentioned object lens is fixed.。

In addition, said here " center prolongation light path " is meant the light path that Snell's law is refraction law (the n1sin θ 1=n2sin θ 2) light that carries out passing through of following of optical axis through object lens.

In addition, said here " phase control element " means the optical element with phase structure, and " phase structure " is the jump with a plurality of the 2nd optical axis directions, to the general name of the structure of incident beam additional optical path difference (phase differential).The optical path difference that is additional to incident beam according to this jump both can be the integral multiple of the wavelength of incident beam, also can be wavelength non-integral multiple of incident beam.Optical path difference as the object lesson of such phase structure has diffraction structure that above-mentioned jump disposes with periodic interval in the optical axis vertical direction or above-mentioned jump to dispose with acyclic interval in the optical axis vertical direction is given structure (be also referred to as phase differential and give structure).

In addition, said here central point or intersection point be meant for " prolonging corresponding to state on the light path at the center " perhaps " prolongs the state through aiming on the light path at the center " having on above-mentioned " center prolongation light path " central point or intersection point, or should " center prolongation light path " and this central point or intersection point between distance be in the state of several μ m with interior (0～3 μ m).

In order to solve above-mentioned problem, the optical Pickup device relevant with technical scheme 1 comprises with the invention of lens unit: object lens are configured in the optical information recording medium side and have the 1st intrinsic optical axis; Phase control element is configured in light source side and holds the 2nd intrinsic optical axis and have opposed two optical surfaces; And holding components; Under the state that above-mentioned the 2nd optical axis tilts with ormal weight with respect to above-mentioned the 1st optical axis, the above-mentioned relatively object lens of above-mentioned phase control element are fixed, and be held within two optical surfaces of above-mentioned phase control element, the central point that formed the optical surface of phase structure prolongs the state through aiming on the light path at the center through above-mentioned the 1st optical axis extending.

In the said lens unit; Because holding components keeps to prolong on the light path at the center through the 1st optical axis extending at least one of 2 central points on the counter surface of phase control element through the state of aiming at, so no matter how the tilt quantity of phase control element can both reduce the coma aberration as lens unit.Promptly; In the both sides' that utilize object lens body and phase control element imaging; Even if phase control element tilts with respect to the object lens body; Be configured after aiming on the light path through a side of the central point of phase control element is prolonged at the center of the 1st optical axis extending that sees through the object lens body, just can suppress the generation of coma aberration.Thereby, no matter be that distance or mutual relative tilt between object lens body and the phase control element can both make the optical property of lens unit be improved simply.

In addition; The invention of the lens unit that technical scheme 2 is put down in writing is in the invention of the lens unit that technical scheme 1 is put down in writing; Phase control element will be given and the object lens body for the interchangeability that making of at least 2 different wavelengths used up; Use at least 2 make use up among when the long side of wavelength, numerical aperture just becomes the state more than or equal to 0.6.

In the case; Just can carry out highdensity record by means of the lens unit of high NA; Though on the aligning of phase control element, require the for example precision below the sub-micron; But can as above-mentioned, suppress the generation of coma aberration, thereby can reach the desired optical property of lens unit simply.

In addition; The invention of the lens unit that technical scheme 3 is put down in writing is in the lens unit that technical scheme 1,2 is put down in writing; Phase control element will be given and the object lens body for the interchangeability that making of at least 2 different wavelengths used up; Use at least 2 make use up among when the long side of wavelength, make the 2nd optical axis with respect to the situation of the 1st optical axis with 3 μ m parallel displacements under, to establish wavelength be λ and make it to take place the coma aberration (coma aberration) more than the 5m λ RMS.

Wherein, RMS representes " root mean square: Root Meam Square ".In the case, though on the aligning of phase control element, require the precision below several microns, can as above-mentioned, suppress the generation of coma aberration, thereby can reach the desired optical property of lens unit simply.

In addition; The invention of the lens unit that technical scheme 4 is put down in writing is in the lens unit that technical scheme 2 to 3 is put down in writing; Phase control element is flat parts; Middle section (centralregion) around at least one side's of above-mentioned opposed two optical surfaces above-mentioned the 2nd optical axis has phase structure, and the neighboring area (peripheralregion) around above-mentioned the 2nd optical axis has tabular surface.

In the case, just can utilize optically focused and the optically focused that utilizes to the higher NA of ratio of the comprehensive incident light of phase control element to the incident light of the middle section of phase control element.

In addition; The invention of the lens unit that technical scheme 5 is put down in writing is in the lens unit that technical scheme 4 is put down in writing; Use at least 2 make use up among when the long side of wavelength, make the making of length of this wavelength use up the middle section that incides phase control element.

In the case; Generally, use up the optically focused that utilizes the comprehensive higher NA of phase control element with making of the short wavelength more higher than general record density with the lower long wavelength's of recording density the optically focused that makes the phase structure of using up the middle section that utilizes phase control element.In addition, when the optically focused that making of short wavelength used up, for example then make phase structure inoperative to optically focused.

In addition; The invention of the lens unit that technical scheme 6 is put down in writing is in the lens unit that technical scheme 1 to 5 is put down in writing; On at least one side of the central point of opposed two optical surfaces of at least one side of the central point of above-mentioned opposed two optical surfaces of above-mentioned phase control element and the above-mentioned object lens that above-mentioned the 1st optical axis passes through, be formed with telltale mark.

In this case, utilized that set specifically labelled easy the aligning just becomes possibility on the both sides of phase control element and object lens body.

In addition, the invention of the lens unit that technical scheme 7 is put down in writing is in the lens unit that technical scheme 6 is put down in writing, and above-mentioned object lens have above-mentioned telltale mark on the central point of the optical surface of above-mentioned phase control element side.

In the case, just become and be easy to come the viewing objective body from the phase control element side.

In addition; The invention of the lens unit that technical scheme 8 is put down in writing is in the lens unit that technical scheme 6,7 is put down in writing, and above-mentioned phase control element has above-mentioned telltale mark on the central point of the optical surface that forms phase structure among opposed two optical surfaces of above-mentioned phase control element.

In the case, can with the phase structure of phase control element the aligning that benchmark carries out phase control element just.

In addition; The invention of the lens unit that technical scheme 9 is put down in writing is in the lens unit that technical scheme 1 to 8 is put down in writing; Phase control element has diffraction structure (diffractivestructure) and optical path difference and gives among the structure (optical pass difference providingstructure) at least 1 as phase structure.

In addition, the invention of the lens unit that technical scheme 10 is put down in writing is in the lens unit that technical scheme 9 is put down in writing, phase structure at least 2 make use up among the short side of wavelength do not attach and phase differential, and the side that wavelength is grown attaches and phase differential.

In the case, just using up the optically focused that utilizes the object lens body with short the making of wavelength just becomes possibility, and using up the optically focused that utilizes object lens body and phase control element with long the making of wavelength just becomes possibility.

In addition; The invention of the lens unit that technical scheme 11 is put down in writing is in the lens unit that technical scheme 1 is put down in writing; Being used to making of at least 2 different wavelengths uses up; One side of opposed two optical surfaces of above-mentioned phase control element; Have acting the 1st phase structure of light to the 1st wavelength of using up one of them at least as making of above-mentioned 2 different wavelengths, the opposing party of above-mentioned opposed two optical surfaces has acting the 2nd phase structure of light to the 2nd wavelength of another one among using up as making of above-mentioned at least 2 different wavelengths.

In the case, just can make lens unit have optically focused characteristic, reduce the generation of coma aberration as lens unit, and the optical property of lens unit is improved corresponding to 2 wavelength or 3 wavelength.

In addition; The invention of the lens unit that technical scheme 12 is put down in writing is in the lens unit that technical scheme 11 is put down in writing; As benchmark, above-mentioned relatively object lens main body is kept by above-mentioned holding components through the involutory state in position above-mentioned phase control element with the side that the influence of the coma aberration that takes place because of off-centre among the above-mentioned the 1st and the 2nd phase structure is bigger.

In the case, through critically aiming at, the optical property of lens unit is improved on all for the bigger phase structure side of coma aberration influence.

In addition; The lens unit that technical scheme 13 is put down in writing is in the lens unit that technical scheme 12 is put down in writing; The object lens main body has telltale mark on the central point of the optical surface of above-mentioned phase control element side, phase control element has telltale mark on the central point of the formed optical surface of the bigger side of influence of the coma aberration that takes place because of off-centre among the above-mentioned the 1st and the 2nd phase structure simultaneously.

In addition; The lens unit that technical scheme 14 is put down in writing is in the lens unit that technical scheme 1 is put down in writing; As being used to the lens unit that making of at least 2 different wavelengths used up; One side of counter surface; Has acting the 1st phase structure of light to the 1st wavelength of one of using up as making of at least 2 different wavelengths; The opposing party of counter surface has acting the 2nd phase structure of light as the 2nd wavelength that makes the another one of using up of 2 different wavelengths at least, and holding components keeps at the state that the reverse direction that prolongs light path perpendicular to this center has squinted 2 central points on the counter surface of phase control element are prolonged light path from the center.

In the case; Just can make lens unit have optically focused characteristic corresponding to 2 wavelength or 3 wavelength, and can be on one side to the generation of adjustment one side minimizing that suit of the coma aberration of each wavelength of taking place because of the 1st and the 2nd phase structure as the coma aberration of lens unit.

In addition; The lens unit that technical scheme 15 is put down in writing is in the lens unit that technical scheme 14 is put down in writing, and the influence of the coma aberration that phase control element takes place respectively to be supported through the involutory state in position that parts are kept with respect to the object lens body so that because of the off-centre of the 1st and the 2nd phase structure is roughly balanced.

In the case, the coma aberration of each wavelength that is taken place because of the 1st and the 2nd phase structure is balanced each other.

In addition; The lens unit that technical scheme 16 is put down in writing is in the lens unit that technical scheme 15 is put down in writing; The object lens body has telltale mark on the central point of phase control element side, phase control element has telltale mark on each central point on the counter surface.

In addition; The lens unit that technical scheme 17 is put down in writing is in the lens unit that technical scheme 1 to 16 is put down in writing, at least 1 inclination mark with expression the 2nd optical axis with respect to the vergence direction of the 1st optical axis in phase control element, object lens body and the holding components.

In the case, optical Pickup device is assembled in the inclination that just can consider phase control element.

In addition; The optical Pickup device that technical scheme 18 is put down in writing; Possess the lens unit that is used on the information recording surface of optical information recording medium, forming luminous point that technical scheme 1 to 17 is put down in writing, and can read the information of optical information recording medium, perhaps writing information in optical information recording medium.

In above-mentioned optical Pickup device can be with assembly process because the optical property of lens unit is improved complicated, so can carry out the record and/or the regeneration of optical information accurately.

In addition, the optical Pickup device that technical scheme 19 is put down in writing, the lens unit that is used on the information recording surface of optical information recording medium, forming luminous point that the scheme that possesses skills 11 is put down in writing; The light of the 1st wavelength can take place, and prolongs the 1st light source that is configured through the state of aiming on the light path with the center at lens unit; And the light that the 2nd wavelength can take place; Be configured so that the 2nd light source that the coma aberration of the lens unit that relevant the 2nd wavelength is taken place reduces from the center prolongation light path dislocation of lens unit; It can read the information of optical information recording medium, perhaps can be in optical information recording medium writing information.

In above-mentioned optical Pickup device can be with assembly process because the optical property of lens unit is improved complicated, so can carry out the record and/or the regeneration of optical information accurately.In the case, the coma aberration of each wavelength that just can realize being taken place because of the 1st and the 2nd phase structure by means of the dislocation of the aligning of the 1st phase structure and the 2nd light source, and can the generation as the coma aberration of lens unit be lowered as far as possible.

In addition, the optical Pickup device that technical scheme 20 is put down in writing is in the optical Pickup device of technical scheme 19 record, and compare with the 2nd phase structure influence of the coma aberration that takes place because of off-centre of the 1st phase structure is bigger.

In the case, just can lower the elimination of coma aberration by means of the dislocation of the 2nd light source, and the burden that can lower design or make.

In addition; The optical Pickup device that technical scheme 21 is put down in writing is in the optical Pickup device of technical scheme 20 records; The object lens main body has telltale mark on the central point of the optical surface of above-mentioned phase control element side, above-mentioned phase control element has telltale mark on the central point of the formed optical surface of the bigger side of influence of the coma aberration that takes place because of off-centre among the above-mentioned the 1st and the 2nd phase structure simultaneously.

In addition; The lens unit that technical scheme 22 is put down in writing is in the said lens unit of technical scheme 1 to 17 record; On the outside surface of above-mentioned holding components and optical information recording medium subtend, the surface with optical information recording medium side optical surface of more above-mentioned object lens also be projected into above-mentioned optical information recording medium side, with teat that elastic body constituted.

According to the said lens unit,, the damage of optical information recording medium is alleviated even if, also can prevent the damage of object lens by means of teat in that optical information recording medium takes place is approaching and collide under the situation of such state of affairs with object lens.

In addition, the lens unit that technical scheme 23 is put down in writing is that on the outside surface of the optical information recording medium subtend of above-mentioned holding components, being coated with fluorine family tree fat is the coating of principal ingredient in the said lens unit of technical scheme 1 to 17 record.

According to the said lens unit, even if, also can the damage of object lens or optical information recording medium alleviated by means of teat in that optical information recording medium takes place is approaching and collide under the situation of such state of affairs with object lens.

In addition, the optical Pickup device relevant with technical scheme 24 is with the invention of lens unit, and possess: object lens are configured in the optical information recording medium side and have intrinsic primary optical axis; Phase control element; Constitute and be configured in the 1st optical surface and 2nd optical surface relative with above-mentioned the 1st optical surface that forms the 2nd phase structure that light source side has formation the 1st phase structure, the 1st secondary optical axis of above-mentioned the 1st optical surface and the 2nd secondary optical axis of above-mentioned the 2nd optical surface are parallel to each other and separate predetermined distance; And holding components, above-mentioned relatively object lens keep above-mentioned phase control element, so that above-mentioned the 1st secondary optical axis and above-mentioned the 2nd secondary optical axis are with respect to above-mentioned primary optical axis inclination predetermined angular.

In the said lens unit; The the 1st and the 2nd secondary optical axis is with respect to the primary optical axis predetermined angular that tilts because holding components is fixed the relative object lens body of phase control element; So phase control element just becomes the state that relative object lens body tilts, just can prevent that back light from phase control element from inciding the imageing sensor of interferometer etc.Thereby, just can reduce influence, and can make the instrumentation high precision int of imaging characteristic simply the back light when the lens unit instrumentation imaging characteristic.

Here, because being parallel to each other, the 1st and the 2nd secondary optical axis separates predetermined distance, so just can the position of the 2nd phase structure on the optical axis vertical direction relatively be adjusted with respect to the position of the 1st phase structure.This just means about the 1st and the 2nd phase structure can distinguish the influence of independent control to imaging characteristic.Its result, for example acquisition has improved the lens unit of imaging characteristic as following.That is to say; Even if the 1st and the 2nd secondary optical axis that is the relative primary optical axis of phase control element are tilted; Through in phase control element, make the 1st and the 2nd secondary optical axis with corresponding to tilt quantity suitably separating appropriate intervals on the direction, just can offset resulting from the influence of the issuable therefrom aberration generation of relative dislocation etc. of the 1st and the 2nd phase structure that inclination took place of phase control element.Particularly, no matter the angle of inclination of phase control element how, all can be aimed at the 1st and the 2nd phase structure with respect to the primary optical axis of object lens body, the imaging characteristic of lens unit is improved.

In addition, the lens unit that technical scheme 25 is put down in writing is in the lens unit that technical scheme 24 is put down in writing, and the 1st and the 2nd secondary optical axis is parallel to the plane that comprises the 1st and the 2nd secondary optical axis with respect to the direction that primary optical axis tilts.

In the case; Owing to can make the vergence direction of constructional dislocation direction and phase control element between the 1st and the 2nd phase structure consistent; So can be just can enough phase control element self prevent to result from the generation of the coma aberration etc. of its inclination, and the imaging characteristic of lens unit is improved.

In addition; The lens unit that technical scheme 26 is put down in writing is in the lens unit that technical scheme 24,25 is put down in writing; Above-mentioned holding components prolongs the above-mentioned relatively object lens of state that process is aimed on the light path at the center of extending through above-mentioned primary optical axis and keeps above-mentioned phase control element with the central point of above-mentioned the 1st optical surface and the central point of above-mentioned the 2nd optical surface.

In the case, just can lower coma aberration exactly according to the tilt quantity of phase control element as lens unit.Thereby, no matter be that distance or mutual relative tilt between object lens body and phase control element can both make the optical property of lens unit be improved simply.

In addition; The lens unit that technical scheme 27 is put down in writing is in the lens unit that technical scheme 26 is put down in writing, and at least one side of the central point of at least one side of the central point of the above-mentioned the 1st and the 2nd optical surface of above-mentioned phase control element and opposed two optical surfaces of above-mentioned object lens that above-mentioned primary optical axis passes through, is formed with telltale mark.

In the case, utilize the specifically labelled easy contraposition that is arranged on phase control element and the object lens body both sides just to become possibility.

In addition, the lens unit that technical scheme 28 is put down in writing is in the lens unit that technical scheme 27 is put down in writing, and the object lens body has telltale mark on the central point of phase control element side.

In the case, just become and be easy to come the viewing objective body from the phase control element side.

In addition; The lens unit that technical scheme 29 is put down in writing is in the lens unit that technical scheme 24 to 28 is put down in writing; Phase control element will be given and the object lens body for the interchangeability that making of 3 different wavelengths used up; Among making of different wavelengths used up, use when the wavelength by at least one side among 2 wavelength of phase control element additive phase, the numerical aperture of the system-wide optical information recording medium side of lens unit becomes the state more than or equal to 0.6.

In the case, though can carry out highdensity record by means of the lens unit of high NA, need make the instrumentation high precision int of the imaging characteristic of lens unit, the aligning that makes phase control element is for example at the following high precision int of sub-micron.According to this lens unit, owing to as above-mentioned, make the instrumentation high precision int of imaging characteristic, the generation of inhibition coma aberration etc. just become possibility, so can make the lens unit that satisfies desired specification expeditiously.

In addition; The lens unit that technical scheme 30 is put down in writing is in the lens unit that technical scheme 24 to 28 is put down in writing; Phase control element is to give the element with the object lens body with the interchangeability of using up for making of 3 different wavelengths; And among making of different wavelengths used up, use the wavelength by at least one side among 2 wavelength of phase control element additive phase to make under the situation of at least one side with respect to primary optical axis parallel displacement 3 μ m of the 1st and the 2nd secondary optical axis, establishing wavelength is λ and the element that makes it to take place the above coma aberration of 5m λ RMS.

Wherein, RMS representes " root mean square: Root Meam Square ".In the case; Also need make the instrumentation high precision int of the imaging characteristic of lens unit; The aligning that makes phase control element is for example at the following high precision int of sub-micron; But because as above-mentioned that works makes the instrumentation high precision int of imaging characteristic and suppress the generation etc. of coma aberration, so can make the lens unit that satisfies desired specification expeditiously.In addition, the coma aberration that takes place about skews such as the secondary optical axis 3 μ m because of phase control element is as being about 5～50m λ RMS in the significant best scope of practicality.

In addition, the lens unit that technical scheme 31 is put down in writing is in the lens unit that technical scheme 24 to 30 is put down in writing, and phase control element has diffraction structure and optical path difference and gives among the structure at least 1 as the 1st and the 2nd phase structure.

In addition; The lens unit that technical scheme 32 is put down in writing is in the lens unit that technical scheme 24 to 29 is put down in writing; Phase control element is to give the element with the object lens body with the interchangeability of using up for making of 3 different wavelengths; And among making of 3 different wavelengths used up the shortest making of the 1st wavelength use up not additional phase error, and among making of 3 different wavelengths used up 2nd and 3rd wavelength also longer than the 1st wavelength make element with the light additional phase error.

In the case, just can make lens unit have optically focused characteristic, thereby the optical property of lens unit is improved corresponding to 3 wavelength.

In addition, the lens unit that technical scheme 32 is put down in writing is in the lens unit that technical scheme 31 is put down in writing, and the object lens body is used up for making of the 1st wavelength and made the spherical aberration correction optimization.

Here, " spherical aberration correction is optimised " is meant and utilizing making of the 1st wavelength to use up corrugated aberration on the information recording surface of institute's optical information recording medium of regenerating or writing down below 0.07 λ RMS.Here λ is the wavelength value of the 1st wavelength.

In addition, the lens unit that technical scheme 33 is put down in writing is in the lens unit that technical scheme 24 to 32 is put down in writing, and has to be used for confirming the mark of the 1st and the 2nd secondary optical axis with respect to the direction of primary optical axis inclination.

In the case, being marked in object lens body, phase control element and the holding components any one goes up directly and forms, or installs as their adjunct.

In addition; The lens unit that technical scheme 34 is put down in writing is in the said lens unit of technical scheme 24 to 33 records; On the outside surface of above-mentioned holding components and optical information recording medium subtend, the surface with optical information recording medium side optical surface of more above-mentioned object lens also be projected into above-mentioned optical information recording medium side, with teat that elastic body constituted.

According to the said lens unit,, the damage of optical information recording medium is alleviated even if, also can prevent the damage of object lens by means of teat in that optical information recording medium takes place is approaching and collide under the situation of such state of affairs with object lens.

In addition, the lens unit that technical scheme 35 is put down in writing is that on the outside surface of above-mentioned holding components and optical information recording medium subtend, being coated with fluorine family tree fat is the coating of major component in the said lens unit of technical scheme 24 to 33 records.

According to the said lens unit, even if, also can the damage of object lens or optical information recording medium alleviated by means of teat in that optical information recording medium takes place is approaching and collide under the situation of such state of affairs with object lens.

In addition, the optical Pickup device that technical scheme 36 is put down in writing is used lens unit, possesses: object lens are configured in the optical information recording medium side and have intrinsic primary optical axis; Phase control element is configured in light source side, has counter surface simultaneously and has the 1st phase structure a side of this counter surface, has the 2nd phase structure the opposing party of this counter surface; And the holding components counter surface tilts with respect to primary optical axis, prolongs on the light path at the center of extending through primary optical axis with the central point of the central point of the 1st phase structure and the 2nd phase structure simultaneously to keep phase control element through the relative object lens body of aiming at of state.

In the said lens unit; Because holding components fix the relative object lens body of phase control element so that counter surface tilts with respect to primary optical axis, incide the imageing sensor of interferometer (interferometer) etc. or the interior light detecting sensor of optical Pickup device so just can prevent back light from phase control element.Thereby, just can alleviate influence to the back light when the lens unit instrumentation imaging characteristic, and the instrumentation that can make imaging characteristic (imagingcharacter) high precision int simply.Equally also can provide a kind of in addition the influence of back light is alleviated, the optical Pickup device that optical property is improved.In addition; In the said lens unit; Because the central point of the 1st phase structure prolongs on the light path through aiming at, so although the tilt quantity of phase control element still can alleviate the coma aberration as lens unit exactly at the center of extending through primary optical axis with the central point of the 2nd phase structure.Thereby, no matter be distance or the mutual relative tilt between object lens body and phase control element, the optical property of lens unit is improved simply.

In addition, the optical Pickup device that technical scheme 37 is put down in writing possesses: the lens unit that technical scheme 22 to 33 is put down in writing, and can read the information of optical information recording medium or writing information in optical information recording medium.

In above-mentioned optical Pickup device can be with assembly process because the optical property of lens unit is improved complicated, so can carry out the record and/or the regeneration of optical information accurately.Particularly; Because can be when the optical characteristics of instrumentation lens unit; Can make the instrumentation high precision int of optical characteristics simply so will lower, and can utilize more high performance lens unit that high precision, optical Pickup device that reliability is high are provided from the back light of lens unit.

In addition; The lens unit that technical scheme 38 is put down in writing is in the said lens unit of technical scheme 36 records; On the outside surface of above-mentioned holding components and optical information recording medium subtend, the surface with optical information recording medium side optical surface of more above-mentioned object lens also is projected into teat above-mentioned optical information recording medium side, that constitute with elastic body.

According to the said lens unit,, the damage of optical information recording medium is alleviated even if, also can prevent the damage of object lens by means of teat in that optical information recording medium takes place is approaching and collide under the situation of such state of affairs with object lens.

In addition, the lens unit that technical scheme 39 is put down in writing is that on the outside surface of above-mentioned holding components and optical information recording medium subtend, being coated with fluorine family tree fat is the coating of major component in the said lens unit of technical scheme 36 records.

According to the said lens unit, even if, also can the damage of object lens or optical information recording medium alleviated by means of teat in that optical information recording medium takes place is approaching and collide under the situation of such state of affairs with object lens.

In addition, the optical Pickup device that technical scheme 40 is put down in writing is used lens unit, has: object lens converge on the information recording surface of optical information recording medium the emergent light from light source; Phase control element, the optical element as be configured in light source side with respect to above-mentioned object lens has the optical surface that is formed with phase structure; And holding components; Keep above-mentioned phase control element; Above-mentioned phase control element, the intersection point that intersects with respect to the optical axis of the inclined light shaft predetermined angular of above-mentioned object lens and above-mentioned phase control element and the optical surface with above-mentioned phase structure with the optical axis of above-mentioned phase control element prolong at the center of the optical axis through above-mentioned object lens that corresponding to state is able to keep on the light path.

In the said lens unit; Because the phase control element that will have a phase structure is supported parts with the state with respect to object lens inclining and is kept, incide the light detecting sensor in the imageing sensor of interferometer etc. or the optical Pickup device so just can prevent back light from phase control element.Thereby, a kind of influence that alleviates the back light when the lens unit instrumentation imaging characteristic just can be provided, and the instrumentation that makes imaging characteristic high precision int simply, the optical Pickup device of optical property through improving.And then; How position like this owing to the intersection point of the optical surface with phase structure and its optical axis is consistent on the optical axis extending center prolongation light path through above-mentioned object lens, so no matter the tilt quantity of phase control element can both lower the coma aberration as lens unit exactly.

In addition, the object lens of technical scheme 41 record is in the lens unit of technical scheme 40 records, and a certain side in above-mentioned holding components and above-mentioned phase control element and the above-mentioned object lens is integrated and form.

According to the said lens unit, through a certain side in phase control element or the object lens is constituted with holding components is integrated with integrally formed etc., just do not need this optical element separately to the maintenance operation of holding components.

In addition, the lens unit of technical scheme 42 records is that above-mentioned phase control element comprises opposed two optical surfaces, has only formed phase structure on a certain side's in light source side and object lens side the optical surface in the lens unit of technical scheme 40 or 41 records.

According to the said lens unit, owing to can use the preferred exchange optical Pickup device of a plurality of wavelength light to use lens unit so can provide to having the wavelength light of giving and being fit to at least 2 object lens that make the interchangeability of using up.

In addition; The lens unit of technical scheme 43 records is in the lens unit of technical scheme 40 or 41 records; Above-mentioned phase control element comprises opposed two optical surfaces, has formed the 2nd phase structure having formed on the 1st optical surface of light source side on the 1st phase structure and the 2nd optical surface in above-mentioned object lens side.

According to the said lens unit; Because can be to having the wavelength light of giving and being fit to, so the lens unit that is suitable for the optical information recording medium of 3 kinds of using 3 wavelength light is had the optical Pickup device of interchangeability can be provided at least 3 object lens that make the interchangeability of using up.

In addition; The lens unit of technical scheme 44 records is in the lens unit of technical scheme 43 records; Above-mentioned holding components; The 2nd intersection point that the 1st intersection point that intersects with the optical axis and above-mentioned the 1st optical surface of above-mentioned the 1st optical surface of above-mentioned phase control element and the optical axis of above-mentioned the 2nd optical surface and above-mentioned the 2nd optical surface intersect, the state that prolongs the light path unanimity about the center of the optical axis through above-mentioned object lens keeps.

According to the said lens unit, no matter how the tilt quantity of phase control element can both lower the coma aberration as lens unit exactly.No matter thereby how the distance between object lens and the phase control element or mutual relative tilt can both make all optical properties of lens unit be improved simply.

In addition; The lens unit of technical scheme 45 records is emergent lights that the lens unit of technical scheme 40 to 42 records is used to have at least 2 different wavelengths light; Above-mentioned phase control element; State in the use at least 2 make use up among when the long side of wavelength, under the situation of optical axis that makes optical axis with respect to above-mentioned object lens, make it to take place the element of the coma aberration more than the 5m λ RMS (λ is a wavelength) with 3 μ m parallel displacements.

According to the said lens unit, even if this element that on the location, requires the precision below the number μ m also can suppress the generation of coma aberration well, and can realize the desired optical property of lens unit simply.

In addition; The lens unit of technical scheme 46 records is in the lens unit of technical scheme 40 to 45 records; Above-mentioned phase control element is the flat-shaped part with opposed two optical surfaces; Above-mentioned phase structure forms on the middle section of at least one face among above-mentioned two optical surfaces, and more above-mentioned middle section constitutes with tabular surface in the neighboring area in the radial direction outside.

According to the said lens unit; Just can utilize to the optically focused of the incident light of the middle section of phase control element with up to the optically focused of the higher NA of ratio that all is used to the incident light that is positioned at its peripheral neighboring area, very effective as the optical Pickup device that is used to through the optical information recording medium of densification with just.

In addition, the lens unit of technical scheme 47 record is in the lens unit of technical scheme 40 to 46 records, on the intersection point of the optical axis of the optical surface of above-mentioned the 1st intersection point of above-mentioned phase control element and above-mentioned object lens and above-mentioned object lens, has telltale mark.

According to the said lens unit, utilize the specifically labelled easy contraposition that is arranged at phase control element and object lens both sides just to become possibility.

In addition; The lens unit of technical scheme 48 records is in the lens unit of technical scheme 40 to 47 records; Be used to have the emergent light of at least 2 different wavelengths light; Above-mentioned phase control element to above-mentioned at least 2 make use up among the short side of wavelength additional phase error not, wavelength is grown side's additional phase error.

According to the said lens unit, short with wavelength once the making to use up and utilize the optically focused of object lens to become possibility of side, carry out good optically focused at phase control element and object lens and become possibility with long the using up of wavelength once making of side.

In addition; The lens unit of technical scheme 49 records is that at least one in above-mentioned phase control element, above-mentioned object lens and the above-mentioned holding components has the mark of expression for the vergence direction of the optical axis of above-mentioned object lens in the lens unit of technical scheme 40 to 48 records.

According to the said lens unit, in the assembly process of optical Pickup device, just can consider the assembling of the inclination of phase control element in advance.

In addition; The lens unit of technical scheme 50 records is in the lens unit of technical scheme 40 to 49 records; Being used to making of at least 2 different wavelengths uses up; One side of opposed two optical surfaces of above-mentioned phase control element; Be formed with acting the 1st phase structure of the 1st wavelength light to one of using up as making of above-mentioned at least 2 different wavelengths, the opposing party is formed with another acting the 2nd phase structure of the 2nd wavelength light among using up that makes as above-mentioned 2 different wavelengths at least.

According to the said lens unit, just can make lens unit have optically focused characteristic, and can provide and make coma aberration that the lens unit that alleviates, optical characteristics is good take place also to be able to corresponding to 2 wavelength or 3 wavelength.

In addition, the optical Pickup device of technical scheme 51 records comprises: the lens unit that technical scheme 50 is put down in writing; Above-mentioned the 1st wavelength light can take place, and prolongs consistent and the 1st light source that is able to keep on the light path at the above-mentioned center of said lens unit; And above-mentioned the 2nd wavelength light can take place; Prolong from the above-mentioned center of said lens unit that the light path dislocation is configured so that the 2nd light source that the coma aberration of the said lens unit that relevant above-mentioned the 2nd wavelength light is taken place reduces, its can carry out optical information recording medium the reading of information, perhaps information is write optical information recording medium.

According to above-mentioned optical Pickup device, owing to can make the optical property improvement of lens unit simply and can not follow the complicated of assembly process, so can carry out the record and/or the regeneration of optical information accurately.

In addition; The lens unit of technical scheme 52 records is in the lens unit of technical scheme 51 records; Optical surface with above-mentioned the 1st phase structure is because of the eccentric coma aberration amount that takes place, the coma aberration amount that takes place greater than the off-centre because of optical surface with above-mentioned the 2nd phase structure.

According to above-mentioned optical Pickup device, just can reduce coma aberration, the burden that can also reduce design or make by means of the dislocation of the 2nd light source.

In addition; The lens unit of technical scheme 53 records is in the lens unit of technical scheme 52 records; Telltale mark with point that the optical surface of phase control element side of optical axis and the above-mentioned object lens of the above-mentioned object lens of expression intersects, above-mentioned phase control element is formed with telltale mark on the point of the optical axis intersection of the bigger side's of the influence of the coma aberration that takes place because of off-centre among each optical surface that forms the above-mentioned the 1st and the 2nd phase structure optical surface and above-mentioned phase control element.

According to above-mentioned optical Pickup device, owing to can preferentially reduce the bigger coma aberration of influence, so design can be provided or the burden made is more high efficiency, the optical Pickup device of excellent optical characteristics.

In addition, the optical Pickup device of technical scheme 54 record is used lens unit, has: make emergent light from light source be focused at the object lens on the information recording surface of optical information recording medium; Be configured in optical element light source side, that comprise opposed two optical surfaces as above-mentioned relatively object lens, on the 1st optical surface of light source side within above-mentioned opposed two optical surfaces, have the 1st phase structure and have the phase control element of the 2nd phase structure at the 2nd optical surface of above-mentioned object lens side; And the holding components that keeps above-mentioned phase control element; The 2nd intersection point that above-mentioned holding components, the 1st intersection point that intersects with respect to the inclined light shaft predetermined angular of above-mentioned object lens and above-mentioned the 1st optical axis and above-mentioned the 1st optical surface with the 2nd optical axis of the 1st optical axis of above-mentioned the 1st optical surface and above-mentioned the 2nd optical surface and above-mentioned the 2nd optical axis and above-mentioned the 2nd optical surface intersect is keeping above-mentioned phase control element about the center consistent state of prolongation light path of the optical axis through above-mentioned object lens respectively.

According to the said lens unit, just can prevent to incide imageing sensor of interferometer etc. from the back light of phase control element, in addition, can also prevent that this back light incides optical sensor when optical Pickup device uses.No matter and, so can provide optical characteristics to use lens unit through the optical Pickup device after improving because how this phase control element can both lower coma aberration exactly with respect to the tilt quantity of object lens.

In addition, the lens unit of technical scheme 55 record is in the lens unit of technical scheme 54 records, and a certain side in above-mentioned holding components and above-mentioned phase control element and the above-mentioned object lens is integrated and form.

According to the said lens unit, through a certain side in phase control element or the object lens is constituted with holding components is integrated with integrally formed etc., like this with regard to do not need this optical element separately to the maintenance operation of holding components.

In addition; The lens unit of technical scheme 56 records is in the lens unit of technical scheme 54 or 55 records; Be used to the lens unit that making of at least 2 different wavelengths used up; Above-mentioned phase control element state in the use at least 2 make use up among when the long side of wavelength, under the situation of optical axis that makes optical axis with respect to anterior object lens, make it to take place the element of the coma aberration more than the 5m λ RMS (λ is a wavelength) with 3 μ m parallel displacements.

According to the said lens unit, even if this element that on the location, requires the precision below the number μ m also can suppress the generation of coma aberration well, and can realize the desired optical property of object lens simply.Though instrumentation high precision int and the aligning that makes phase control element of imaging characteristic that just need make object lens is for example with the following high precision int of sub-micron (μ m); But owing to can make the instrumentation high precision int of imaging characteristic and suppress the generation etc. of coma aberration, so can make the lens unit that satisfies desired specification expeditiously.In addition, the coma aberration that takes place because of the light shaft offset 3 μ m of phase control element is as being about 5～50m λ RMS in scope best in the practicality.

In addition; The lens unit of technical scheme 57 records is in the lens unit of technical scheme 54 to 56 records; Be used to the lens unit that making of at least 3 different wavelengths used up; Above-mentioned phase control element, the making of the 1st wavelength of the shortest wavelength used up not additional phase error among will using up for making of above-mentioned 3 different wavelengths, and making of the 2nd and the 3rd wavelength also longer than above-mentioned the 1st wavelength among making of above-mentioned 3 different wavelengths used up used the light additional phase error.

According to the said lens unit, just can make lens unit have optically focused characteristic, and the optical property of lens unit is improved corresponding to 3 wavelength.

In addition, the optical Pickup device of technical scheme 58 record can utilize the lens unit of technical scheme 54 to 57 records, reads the information of optical information recording medium, perhaps information is write optical information recording medium.

In addition, the optical Pickup device of technical scheme 59 record has with lens unit: make emergent light from light source be focused at the object lens on the information recording surface of optical information recording medium; Above-mentioned relatively object lens are configured in light source side and comprise opposed two optical surfaces, are forming the phase control element that forms the 2nd phase structure on the 1st phase structure and the 2nd optical surface in above-mentioned object lens side on the 1st optical surface of light source side among above-mentioned opposed two optical surfaces; And the holding components that keeps above-mentioned phase control element; Above-mentioned holding components with respect to the inclined light shaft predetermined angular of above-mentioned object lens and make among the above-mentioned the 1st and the 2nd optical surface, because of the bigger side's of influence of the eccentric coma aberration that takes place the optical surface and the intersection point of optical axis intersection, the state of unanimity is keeping above-mentioned phase control element on the center prolongation light path of the optical axis extending through above-mentioned object lens.

According to the said lens unit, owing to can the bigger coma aberration of influence preferentially be lowered, so the optical property of lens unit is improved as a whole.

In addition, the object lens of technical scheme 59 record is in the lens unit of technical scheme 58 records, and a certain side in above-mentioned holding components and above-mentioned phase control element and the above-mentioned object lens is integrated and form.

According to the said lens unit, through a certain side in phase control element or the object lens is constituted with holding components is integrated with integrally formed etc., like this with regard to do not need this optical element separately to the maintenance operation of holding components.

In addition; The lens unit of technical scheme 60 records is in the lens unit of technical scheme 58 or 59 records; This lens unit is used to making of at least 2 different wavelengths and uses up; One of optical surface of above-mentioned phase control element; Be formed with acting the 1st phase structure of the 1st wavelength light to one of using up as making of above-mentioned at least 2 different wavelengths, another is formed with another acting the 2nd phase structure of the 2nd wavelength light among using up that makes as above-mentioned 2 different wavelengths at least.

According to the said lens unit, just can make lens unit have optically focused property corresponding to 2 wavelength or 3 wavelength, can suppress to influence bigger coma aberration effectively as lens unit, and optical property is improved as lens unit.

In addition; The object lens of technical scheme 61 records is in the lens unit of technical scheme 58 to 60 records; Above-mentioned object lens have telltale mark on the central point of the optical surface of above-mentioned phase control element side, above-mentioned phase control element has telltale mark on the central point because of the bigger formed optical surface of a side of the influence of the eccentric coma aberration that takes place among the above-mentioned the 1st and the 2nd phase structure.

According to the said lens unit, owing to become easily with the location of the bigger optical surface of coma aberration generating capacity, so can the lens unit of optical property through improvement be provided through simple operation.

In addition; The lens unit of technical scheme 62 records is that at least one in above-mentioned phase control element, above-mentioned object lens and the above-mentioned holding components has the mark of expression with respect to the vergence direction of the optical axis of above-mentioned object lens in the lens unit of technical scheme 58 to 61 records.

According to the said lens unit, the inclination that just can consider phase control element is assembled optical Pickup device simply and is used lens unit.

In addition, the optical Pickup device of technical scheme 63 records possesses the lens unit of technical scheme 58 to 62 records, and can read the information of optical information recording medium, perhaps information is write optical information recording medium.

According to the said lens unit, the optical Pickup device of optical property through improving just can be provided.

In addition, the optical Pickup device of technical scheme 64 record is used lens unit, has: make emergent light from light source be focused at the object lens on the information recording surface of optical information recording medium; Above-mentioned relatively object lens are configured in light source side, comprise opposed two optical surfaces, are forming the phase control element that forms the 2nd phase structure on the 1st phase structure and the 2nd optical surface in above-mentioned object lens side on the 1st optical surface of light source side among above-mentioned opposed two optical surfaces; And the holding components that keeps above-mentioned phase control element; Above-mentioned holding components, to prolong the light path dislocation from the center of the optical axis extending through above-mentioned object lens respectively with respect to the 2nd intersection point of the 1st intersection point of the inclined light shaft predetermined angular of above-mentioned object lens and above-mentioned the 1st optical surface and its optical axis and above-mentioned the 2nd optical surface and its optical axis so that because of the above-mentioned the 1st and the coma aberration that takes place respectively of the off-centre of the 2nd optical surface roughly the state of equilibrium keeping above-mentioned phase control element.

The said lens unit just can make by optical surface with the 1st phase structure and the coma aberration balance that the optical surface with the 2nd phase structure takes place respectively and reduce well, and can provide as the good lens unit of optical characteristics.

In addition, the lens unit of technical scheme 65 record is in the lens unit of technical scheme 64 records, and a certain side in above-mentioned holding components and above-mentioned phase control element and the above-mentioned object lens is integrated and form.

According to the said lens unit, through a certain side in phase control element or the object lens is constituted with holding components is integrated with integrally formed etc., like this with regard to do not need this optical element separately to the maintenance operation of holding components.

In addition; The lens unit of technical scheme 66 records is in the lens unit of technical scheme 64 or 65 records; Be used to the lens unit that making of at least 2 different wavelengths used up; One side of opposed two optical surfaces of above-mentioned phase control element; Have acting the 1st phase structure of one the 1st wavelength light in using up as making of above-mentioned at least 2 different wavelengths, the opposing party has another acting the 2nd phase structure of the 2nd wavelength light in using up that makes to above-mentioned at least 2 different wavelengths.

According to the said lens unit, just can make lens unit have optically focused property corresponding to 2 wavelength or 3 wavelength, can suppress to influence bigger coma aberration effectively as lens unit, and optical property is improved as lens unit.

In addition; The lens unit of technical scheme 67 records is in the lens unit of technical scheme 64 to 66 records; Above-mentioned object lens with the intersection point of the optical axis of the optical surface of above-mentioned phase control element side on form telltale mark, above-mentioned phase control element has telltale mark respectively on the above-mentioned the 1st and the 2nd intersection point.

According to the said lens unit, owing to become easily with the location of the bigger optical surface of coma aberration generating capacity, so can the lens unit of optical property through improvement be provided through simple operation.

In addition, the invention of technical scheme 67 records is that at least one in above-mentioned phase control element, above-mentioned object lens and the above-mentioned holding components has the mark of expression with respect to the vergence direction of the optical axis of above-mentioned object lens in the lens unit of technical scheme 64 to 67 records.

According to the said lens unit, the inclination that just can consider phase control element is assembled optical Pickup device simply and is used lens unit.

In addition, the optical Pickup device of technical scheme 68 records possesses the lens unit of technical scheme 64 to 68 records, and can read the information of optical information recording medium, perhaps information is write optical information recording medium.

According to the said lens unit, the optical Pickup device of optical property through improving just can be provided.

In addition, the optical Pickup device of technical scheme 69 record is used lens unit, has: make emergent light from light source be focused at the object lens on the information recording surface of optical information recording medium; Above-mentioned relatively object lens are configured in light source side, comprise opposed two optical surfaces, are forming the phase control element that forms the 2nd phase structure on the 1st phase structure and the 2nd optical surface in above-mentioned object lens side on the 1st optical surface of light source side among above-mentioned opposed two optical surfaces; And the holding components that keeps above-mentioned phase control element; Above-mentioned phase control element constitutes each optical axis that makes the above-mentioned the 1st and the 2nd optical surface and is parallel to each other and separates predetermined distance, and above-mentioned holding components is keeping above-mentioned phase control element with each optical axis of the above-mentioned the 1st and the 2nd optical surface with respect to the state that the inclined light shaft predetermined angular of above-mentioned object lens tilts.

According to the said lens unit, incide the imageing sensor of interferometer etc. owing to can prevent back light from position control component, so the instrumentation that just can make imaging characteristic high precision int simply.In addition, because because the back light from this phase control element the during use of optical Pickup device incides the situation of optical sensor also can prevent equally, so the optical Pickup device of optical property through improvement just can be provided.And then; Because the position with respect to the 1st phase structure of phase control element is relatively adjusted the position of the optical axis vertical direction of the 2nd phase structure, just can be controlled independently each phase structure; So through make in phase control element each optical axis with corresponding to tilt quantity suitably separating appropriate intervals on the direction, just can offset resulting from the influence of the issuable therefrom aberration generation of relative dislocation etc. of the 1st and the 2nd phase structure that inclination took place of phase control element.Each optical axis that can also make phase control element in addition is all along consistent on the prolongation light path of the optical axis extending of object lens and no matter the angle of inclination how, and can make the optical characteristics of lens unit improve more.

In addition, the optical Pickup device of technical scheme 70 records is used optical element, has: the 1st optical surface of the 1st phase structure; And be arranged on and opposed the 2nd optical surface of going up, having the 2nd phase structure of above-mentioned the 1st optical surface, the optical axis of the optical axis of above-mentioned the 1st optical surface and above-mentioned the 2nd optical surface is parallel to each other and separates formation with predetermined distance.

Above-mentioned optical element can also prevent when optical Pickup device uses that the back light of the incident light on this optical element from inciding optical sensor, also can prevent to incide the situation of the imageing sensor etc. of interferometer in addition during instrumentation equally in imaging.And then, even if because under the situation that this optical element tilts, also can and other optical elements between to carry out the good optical axis of precision involutory, so few optical system of the problem of coma aberration or optical Pickup device etc. can be provided.

In addition, the optical Pickup device of technical scheme 71 record is used picture frame, comprising: the 1st maintaining part has the 1st reference field that position the 1st optical element, optical axis direction is limited and the 1st fitting portion to limiting perpendicular to the position of the direction of optical axis; And the 2nd maintaining part; Also be provided with, have the 2nd reference field that the position 2nd optical element, optical axis direction different with above-mentioned the 1st optical element limited and the 2nd fitting portion than above-mentioned the 1st maintaining part to limiting perpendicular to the position of the direction of optical axis by light source side; One side of the wherein above-mentioned the 1st and the 2nd reference field forms with respect to the face tilt vertical with optical axis.

According to above-mentioned picture frame; Bring the influence of sensor etc. owing to the back light of considering the incident light that a plurality of optical elements of reason take place; Constitute after making the 1st or the 2nd reference field with respect to the face tilt vertical in advance, so alleviate with producing effect and need not consider that optical element tilts and just become possibility simply installing with optical axis.

In addition; The picture frame of technical scheme 72 records; In the picture frame of technical scheme 71 records, at least one side of the above-mentioned the 1st and the 2nd fitting portion has in the above-mentioned the 1st and the 2nd reference field of at least one side's butt of the 1st and the 2nd optical element of butt can be in the gap of carrying out the position adjustment perpendicular to the direction of optical axis.

According to above-mentioned picture frame, the influence because of the coma aberration that optical element caused that kept is suppressed to keep just to become possibility.

In addition; The picture frame that technical scheme 73 is put down in writing; Be in the picture frame of technical scheme 71 or 72 records; With the outside surface of the optical information recording medium subtend of above-mentioned picture frame on, the surface with optical information recording medium side optical surface of more above-mentioned object lens also is projected into teat above-mentioned optical information recording medium side, that constitute with elastic body.

According to above-mentioned picture frame,, the damage of optical information recording medium is alleviated even if, also can prevent the damage of object lens by means of teat in that optical information recording medium takes place is approaching and collide under the situation of such state of affairs with object lens.

In addition, the picture frame that technical scheme 74 is put down in writing is that on the outside surface of the optical information recording medium subtend of above-mentioned holding components, being coated with fluorine family tree fat is the coating of principal ingredient in the picture frame of technical scheme 71 or 72 records.

According to above-mentioned picture frame, even if, also can the damage of object lens or optical information recording medium alleviated by means of teat in that optical information recording medium takes place is approaching and collide under the situation of such state of affairs with object lens.

In addition; The optical Pickup device of technical scheme 75 records; Be used to emergent light from light source and carry out information to the 1st optical information recording medium and have protective substrate thickness t 2 (record of each information recording surface of the 2nd optical information recording medium of t1≤t2) and/or information are from the regeneration of each information recording surface, and this optical Pickup device comprises: outgoing has the 1st light source of the 1st laser of wavelength X 1 with protective substrate thickness t 1; Outgoing has the 2nd light source of the 2nd laser of wavelength X 2 (λ 1＜λ 2); Make the object lens of the above-mentioned the 1st and the 2nd laser difference optically focused at the 1st and the 2nd optical information recording medium; And above-mentioned relatively object lens are configured in light source side; Possesses phase control element to the optical surface of controlling from the phase place of the emergent light of above-mentioned light source with phase structure; Wherein, Above-mentioned object lens and above-mentioned phase control element, the 1st intersection point that intersects with respect to the inclined light shaft predetermined angular of above-mentioned object lens and optical axis that makes above-mentioned phase control element and the optical surface with above-mentioned phase structure with the optical axis of above-mentioned phase control element prolong the consistent state of light path about the center of the optical axis through above-mentioned object lens and are able to maintenance.

According to above-mentioned optical Pickup device; Use the wavelength light of different wavelength to carry out in the optical Pickup device of recording of information and/or regeneration at optical information recording medium to different at least 2 kinds; Just can prevent to bring the influence of sensor etc., and optical Pickup device influence, that optical characteristics is good of the coma aberration that has alleviated phase control element can be provided because of the back light of the incident light that comes from phase control element.

In addition, the optical Pickup device of technical scheme 76 record is in the optical Pickup device of technical scheme 75 records, and above-mentioned object lens and above-mentioned phase control element are to be able to the lens unit that keeps by means of holding components.

According to above-mentioned optical Pickup device, just can carry out object lens body and the relative positioning of phase control element on the optical axis vertical direction with high precision in advance.

In addition; The optical Pickup device of technical scheme 77 records is further in the optical Pickup device of technical scheme 74 or 75 records; (record of the information recording surface of the 3rd optical information recording medium of t2＜t3) and/or information are from the regeneration of information recording surface, and this optical Pickup device also comprises: outgoing is to the 3rd light source of used the 3rd laser with wavelength X 3 (λ 2＜λ 3) of above-mentioned the 3rd optical information recording medium to having the 3rd protective substrate thickness t 3 for the information of carrying out.

According to above-mentioned optical Pickup device; Used in the optical Pickup device of wavelength light of 3 different wavelength at optical information recording medium different at least 3 kinds; Just can prevent to bring the influence of sensor etc., and optical Pickup device influence, that optical characteristics is good of the coma aberration that has alleviated phase control element can be provided because of the back light of the incident light that comes from phase control element.

In addition; The optical Pickup device of technical scheme 78 records; To the 1st optical information recording medium with protective substrate thickness t 1, have protective substrate thickness t 2 (the 2nd optical information recording medium of t1≤t2) and have protective substrate thickness t 3 (each the information recording surface recorded information of the 3rd optical information recording medium of t2≤t3) and/or the information of carrying out are from the regeneration of each information recording surface, and this optical Pickup device comprises: outgoing has the 1st light source of the 1st laser of wavelength X 1; Outgoing has the 2nd light source of the 2nd laser of wavelength X 2 (λ 1＜λ 2); Outgoing has the 3rd light source of the 3rd laser of wavelength X 3 (λ 2＜λ 3); Make the object lens of above-mentioned the 1st, the 2nd and the 3rd laser difference optically focused at the 1st, the 2nd and the 3rd optical information recording medium; And above-mentioned relatively object lens are configured in light source side, comprise opposed two optical surfaces; Forming the phase control element that forms the 2nd phase structure on the 1st phase structure and the 2nd optical surface on the 1st optical surface of light source side among above-mentioned opposed two optical surfaces in above-mentioned object lens side; Wherein, The 2nd intersection point that above-mentioned phase control element, the 1st intersection point that intersects with respect to the inclined light shaft predetermined angular of above-mentioned object lens and above-mentioned the 1st optical axis and above-mentioned the 1st optical surface with the 2nd optical axis of the 1st optical axis of above-mentioned the 1st optical surface and above-mentioned the 2nd optical surface and above-mentioned the 2nd optical axis and above-mentioned the 2nd optical surface intersect prolongs the consistent state of light path about the center of the optical axis through above-mentioned object lens respectively and is able to maintenance.

According to above-mentioned optical Pickup device; Used in the optical Pickup device of wavelength light of 3 different wavelength at optical information recording medium different at least 3 kinds; Just can prevent to incide imageing sensor of interferometer etc. from the back light of phase control element; And because no matter how this phase control element can both reduce coma aberration exactly for the tilt quantity of object lens, so the optical Pickup device that can provide optical characteristics to improve more.

In addition, the optical Pickup device of technical scheme 79 record is in the optical Pickup device of technical scheme 78 records, and above-mentioned object lens and above-mentioned phase control element are to be able to the lens unit that keeps by means of holding components.

In addition; The optical Pickup device of technical scheme 80 records is further in the optical Pickup device of technical scheme 78 or 79 records; (record of the information recording surface of the 3rd optical information recording medium of t2＜t3) and/or information are from the regeneration of information recording surface, and this optical Pickup device also comprises: outgoing is to the 3rd light source of used the 3rd laser with wavelength X 3 (λ 2＜λ 3) of above-mentioned the 3rd optical information recording medium to having the 3rd protective substrate thickness t 3 for the information of carrying out.

According to above-mentioned optical Pickup device; Used in the optical Pickup device of wavelength light of 3 different wavelength at optical information recording medium for different at least 3 kinds; Just can prevent to bring the influence of sensor because of the incident light that comes from phase control element, no matter and optical Pickup device influence, that optical characteristics is good and phase control element that the coma aberration that has alleviated phase control element can be provided for the tilt quantity of object lens how.

In addition; The optical Pickup device of technical scheme 81 records; To the 1st optical information recording medium with protective substrate thickness t 1, have protective substrate thickness t 2 (the 2nd optical information recording medium of t1≤t2) and have protective substrate thickness t 3 (each the information recording surface recorded information of the 3rd optical information recording medium of t2≤t3) and/or the information of carrying out are from the regeneration of each information recording surface, and this optical Pickup device comprises: outgoing has the 1st light source of the 1st laser of wavelength X 1; Outgoing has the 2nd light source of the 2nd laser of wavelength X 2 (λ 1＜λ 2); Outgoing has the 3rd light source of the 3rd laser of wavelength X 3 (λ 2＜λ 3); Make the object lens of above-mentioned the 1st, the 2nd and the 3rd laser difference optically focused at the 1st, the 2nd and the 3rd optical information recording medium; And above-mentioned relatively object lens are configured in light source side, comprise opposed two optical surfaces; Forming the phase control element that forms the 2nd phase structure on the 1st phase structure and the 2nd optical surface on the 1st optical surface of light source side among above-mentioned opposed two optical surfaces in above-mentioned object lens side; Wherein, Above-mentioned object lens and above-mentioned phase control element, with respect to the inclined light shaft predetermined angular of above-mentioned object lens and make among the above-mentioned the 1st and the 2nd optical surface, because of the intersection point of the bigger side's of the influence of the coma aberration that off-centre was taken place optical surface and optical axis intersection, prolong the consistent state of light path about the center of the optical axis extending through above-mentioned object lens and be able to maintenance.

According to above-mentioned optical Pickup device; Used in the optical Pickup device of wavelength light of 3 different wavelength at optical information recording medium different at least 3 kinds; Just can prevent to bring the influence of sensor etc., and can suppress to influence the influence of bigger coma aberration, the optical Pickup device that provides optical characteristics to improve effectively because of the back light of the incident light that comes from phase control element.

In addition, the optical Pickup device of technical scheme 82 record is in the optical Pickup device of technical scheme 81 records, and above-mentioned object lens and above-mentioned phase control element are to be able to the lens unit that keeps by means of holding components.

In addition; The optical Pickup device of technical scheme 83 records; To the 1st optical information recording medium with protective substrate thickness t 1, have protective substrate thickness t 2 (the 2nd optical information recording medium of t1≤t2) and have protective substrate thickness t 3 (each the information recording surface recorded information of the 3rd optical information recording medium of t2≤t3) and/or the information of carrying out are from the regeneration of each information recording surface, and this optical Pickup device comprises: outgoing has the 1st light source of the 1st laser of wavelength X 1; Outgoing has the 2nd light source of the 2nd laser of wavelength X 2 (λ 1＜λ 2); Outgoing has the 3rd light source of the 3rd laser of wavelength X 3 (λ 2＜λ 3); Make the object lens of above-mentioned the 1st, the 2nd and the 3rd laser difference optically focused at the 1st, the 2nd and the 3rd optical information recording medium; And above-mentioned relatively object lens are configured in light source side, comprise opposed two optical surfaces; Forming the phase control element that forms the 2nd phase structure on the 1st phase structure and the 2nd optical surface on the 1st optical surface of light source side among above-mentioned opposed two optical surfaces in above-mentioned object lens side; Above-mentioned phase control element; With inclined light shaft predetermined angular with respect to above-mentioned object lens, and the 2nd intersection point of the 1st intersection point of above-mentioned the 1st optical surface and its optical axis and above-mentioned the 2nd optical surface and its optical axis prolong the light path dislocation from the center of the optical axis extending through above-mentioned object lens respectively so that because of the above-mentioned the 1st and the roughly balanced state of coma aberration that takes place respectively of the off-centre of the 2nd optical surface be able to maintenance.

According to above-mentioned optical Pickup device; Used in the optical Pickup device of wavelength light of 3 different wavelength at optical information recording medium different at least 3 kinds; Just can prevent that the back light because of the incident light that comes from phase control element from bringing the influence of optical sensor; And can make by optical surface with the 1st phase structure and the coma aberration balance that the optical surface with the 2nd phase structure is taken place separately and lower well, thereby the optical Pickup device that does well as optical characteristics can be provided.

In addition, the optical Pickup device of technical scheme 84 record is in the optical Pickup device of technical scheme 83 records, and above-mentioned object lens and above-mentioned phase control element are to be able to the lens unit that keeps by means of holding components.

In addition; The optical Pickup device of technical scheme 85 records; To the 1st optical information recording medium with protective substrate thickness t 1, have protective substrate thickness t 2 (the 2nd optical information recording medium of t1≤t2) and have protective substrate thickness t 3 (each the information recording surface recorded information of the 3rd optical information recording medium of t2≤t3) and/or the information of carrying out are from the regeneration of each information recording surface, and this optical Pickup device comprises: outgoing has the 1st light source of the 1st laser of wavelength X 1; Outgoing has the 2nd light source of the 2nd laser of wavelength X 2 (λ 1＜λ 2); Outgoing has the 3rd light source of the 3rd laser of wavelength X 3 (λ 2＜λ 3); Make the object lens of above-mentioned the 1st, the 2nd and the 3rd laser difference optically focused at the 1st, the 2nd and the 3rd optical information recording medium; And above-mentioned relatively object lens are configured in light source side, comprise opposed two optical surfaces; Forming the phase control element that forms the 2nd phase structure on the 1st phase structure and the 2nd optical surface on the 1st optical surface of light source side among above-mentioned opposed two optical surfaces in above-mentioned object lens side; Wherein, Above-mentioned phase control element; Each optical axis of the above-mentioned the 1st and the 2nd optical surface is parallel to each other separates formation, be able to keep with respect to the state of the inclined light shaft predetermined angular of above-mentioned object lens with each optical axis of the above-mentioned the 1st and the 2nd optical surface simultaneously with predetermined distance.

According to above-mentioned optical Pickup device; Used in the pickup apparatus of wavelength light of 3 different wavelength at optical information recording medium different at least 3 kinds; Just can prevent to incide optical sensor from the back light of position control component; In addition through in phase control element with each optical axis suitably to separate appropriate intervals on the direction corresponding to tilt quantity; Though then the angle of inclination how also can make phase control element each optical axis all along consistent on the prolongation light path of the optical axis extending of object lens, and the optical Pickup device that can improve optical characteristics can be provided.

In addition, the optical Pickup device of technical scheme 86 record is in the optical Pickup device of technical scheme 85 records, and above-mentioned object lens and above-mentioned phase control element are to be able to the lens unit that keeps by means of holding components.

In addition; The optical Pickup device of technical scheme 87 records is with the assembly method of lens unit; This optical Pickup device has holding components with lens unit; Make emergent light from light source be focused at object lens on the information recording surface of optical information recording medium and the phase control element with the optical surface that forms phase structure, this assembly method comprises: the 1st step that above-mentioned object lens are installed at above-mentioned holding components; Above-mentioned phase control element is installed on above-mentioned holding components so that the optical axis of optical surface with above-mentioned phase structure with respect to the 2nd step of the inclined light shaft of above-mentioned object lens; The phase control element of being installed on the above-mentioned holding components and above-mentioned object lens are carried out the position adjustment, so that the intersection point that the optical axis of the optical surface of the formation phase structure of above-mentioned phase control element and the optical surface with above-mentioned phase structure intersect places the center of the optical axis extending through above-mentioned object lens to prolong the 3rd step on the light path; The 4th step that the above-mentioned relatively holding components of above-mentioned phase control element is fixed; And the 5th step that the above-mentioned relatively holding components of above-mentioned object lens is fixed.

According to according to above-mentioned assembly method; Just can prevent that back light because of the incident light that incides phase control element from bringing the harmful effect of optical sensor etc., and can provide the influence that reduced the coma aberration that causes because of phase control element, the lens unit of optical characteristics through improving.

In addition; The assembly method of technical scheme 88 records is in the assembly method of technical scheme 87 records; Above-mentioned phase control element; To give and above-mentioned object lens for the interchangeability that making of at least 2 different wavelengths used up; One side of two optical surfaces of subtend has acting the 1st phase structure of light to the 1st wavelength of one of using up as making of above-mentioned at least 2 different wavelengths, and the opposing party has another acting the 2nd phase structure of the 2nd wavelength light in using up that makes as above-mentioned 2 different wavelengths at least.

According to above-mentioned assembly method,, the lens unit of optical characteristics through improving just can be provided as the lens unit that has corresponding to the optically focused property of 2 wavelength or 3 wavelength.

In addition; The assembly method of technical scheme 89 record is in the assembly method of technical scheme 87 or 88 records, and above-mentioned the 3rd step is to carry out the position adjustment so that the 1st optical surface of above-mentioned the 1st phase structure of the formation of above-mentioned phase control element and forming among the 2nd optical surface of the 2nd phase structure because of the optical axis of the bigger side's of the influence of the eccentric coma aberration that takes place optical surface and the crossing intersection point of this optical surface is configured on the center prolongation light path of the optical axis extending through above-mentioned object lens.

According to above-mentioned assembly method, as the lens unit that has corresponding to the optically focused property of 2 wavelength or 3 wavelength, just can provide and make that the bigger coma aberration of influence is able to alleviate effectively, optical characteristics is through the lens unit of improvement.

In addition; The optical Pickup device of technical scheme 90 records is with the assembly method of lens unit; This optical Pickup device has holding components with lens unit; Make emergent light from light source be focused at the object lens on the information recording surface of optical information recording medium and have the 1st optical surface that forms the 1st phase structure and have the phase control element of the 2nd optical surface of the 2nd phase structure, this assembly method comprises: the 1st step that above-mentioned object lens are installed at above-mentioned holding components; Above-mentioned phase control element is installed, so that its 2nd step that tilts with respect to the direction vertical with the optical axis of above-mentioned object lens on above-mentioned holding components; Above-mentioned phase control element of installing is carried out position adjustment, and the state that the 2nd intersection point of the 1st intersection point of above-mentioned the 1st optical surface and its optical axis and above-mentioned the 2nd optical surface and its optical axis is configured to misplace from the center prolongation light path of the optical axis extending through above-mentioned object lens is so that because of the above-mentioned the 1st and the coma aberration that takes place respectively of the off-centre of the 2nd optical surface the 3rd step of equilibrium roughly; The 4th step that the above-mentioned relatively holding components of above-mentioned phase control element is fixed; And the 5th step that the above-mentioned relatively holding components of above-mentioned object lens is fixed.

According to above-mentioned assembly method; Bring the harmful effect of imageing sensor etc. owing to can prevent back light because of the incident light that incides phase control element; And can make the coma aberration balance that is taken place separately because of optical surface with the 1st phase structure and optical surface be able to well lower, so can provide as the good lens unit of optical characteristics with the 2nd phase structure.

In addition; The assembly method of technical scheme 91 records is in the assembly method of technical scheme 90 records; Above-mentioned phase control element will be given and above-mentioned object lens for the interchangeability that making of at least 2 different wavelengths used up; The light of one the 1st wavelength during the optical surface with above-mentioned the 1st phase structure is used up for making of above-mentioned 2 different wavelengths at least works, and the optical surface with above-mentioned the 2nd phase structure works for another the 2nd wavelength light in using up that makes of above-mentioned 2 different wavelengths at least.

According to above-mentioned assembly method,, the lens unit of optical characteristics through improving just can be provided as the lens unit that has corresponding to the optically focused property of 2 wavelength or 3 wavelength.

The present invention itself and other characteristics and advantage combine the following detailed description of accompanying drawing will be able to best appreciated through reference.

Description of drawings

Fig. 1 is the side sectional drawing of the lens unit of the 1st embodiment.

Fig. 2 is the front view (FV) that constitutes the diffraction lens of lens unit.

Fig. 3 (a)～(h) is the sectional drawing of explanation at the concrete example of the formed phase structure of middle section of diffraction lens.

Fig. 4 (a)～(h) is the sectional drawing of explanation at the concrete example of the formed phase structure of middle section of diffraction lens.

Fig. 5 is the expanded view of aligning of the object lens of key diagram 1.

Fig. 6 is the expanded view of aligning of the object lens of key diagram 1.

Fig. 7 is the expanded view of aligning of the object lens of explanation the 2nd embodiment.

Fig. 8 is the side sectional drawing of the lens unit of the 3rd embodiment.

Fig. 9 is the side sectional drawing of the lens unit of the 4th embodiment.

Figure 10 is the front view (FV) of diffraction lens that constitutes the lens unit of the 5th embodiment.

Figure 11 is the block diagram of structure of the optical Pickup device of explanation the 6th embodiment.

Figure 12 is the cross-sectional side view of the lens unit of the 7th embodiment.

Figure 13 is the expanded view of aligning of the object lens of explanation the 7th embodiment.

Figure 14 is the figure that the optical Pickup device of lens unit shown in Figure 13 has been assembled in expression.

Figure 15 is the cross-sectional side view of the lens unit of the 8th embodiment.

Figure 16 is the expanded view of aligning of the object lens of explanation the 8th embodiment.

Figure 17 is lens unit is observed in expression from light source side a state.

Figure 18 is the expanded view of the aligning of the object lens in explanation the 9th embodiment.

Figure 19 is the figure of the optical Pickup device of expression the 9th embodiment.

Figure 20 is the figure that the vertical section structure of the 3 wavelength semiconductor laser of in optical Pickup device shown in Figure 19, being assembled is described.

Figure 21 is the side sectional drawing of the lens unit of the 10th embodiment.

Figure 22 (a)～(h) is the sectional drawing of explanation at the concrete example of the formed phase structure of single face of diffraction lens.

Figure 23 (a)～(h) is the sectional drawing of explanation at the concrete example of the formed phase structure of single face of diffraction lens.

Figure 24 is the figure that the position deviation of the two phase place structural plane that constitutes diffraction lens is described.

Figure 25 is the expanded view of aligning of the object lens of explanation Figure 21.

Figure 26 is the expanded view of aligning of the object lens of explanation Figure 21.

Figure 27 is that explanation is used for the figure to the device of the object lens instrumentation optical characteristics of Figure 21.

Figure 28 is the side sectional drawing of the lens unit of the 11st embodiment.

Figure 29 is the figure of the optical Pickup device of expression the 12nd embodiment.

In the explanation, run through a plurality of accompanying drawings and specify same or analogous parts with reference to label below with identical.

Embodiment

(the 1st embodiment)

Fig. 1 is the cross-sectional side view of the object lens 50 used with the relevant light picker of the present invention's the 1st embodiment; This object lens 50 has interchangeability for the mutual different two kinds of CDs (for example DVD and BD) of specification (recording density etc.), can on these CDs, constitute on recording/reproducing information ground.In addition, this object lens 50 has convergence forms focal point from the laser (make and use up) of not shown light source and on not shown CD the object lens body 1 as object optical element; Be used to form the diffraction lens 2 as phase control element of diffraction light; And be used for the integrated picture frame 3 that fixes of object lens body 1 and diffraction lens 2 as the barrel shape of holding components.Here, object lens body 1 is for example formed by materials such as glass, and diffraction lens 2 forms with picture frame 3 for example adds the fine glass particle of tens of number percents by plastics or in plastics material.

Object lens body 1 is as the big projection of the 1st 1a of the optical surface of diffraction lens 2 sides and the 2nd the aspheric biconvex lens that 1b relatively is formed flatly of CD side (figure right side of face), and the diffraction light or the non-diffracted light corresponding to a pair of different wave length of self-diffraction lens 2 regulation that converges at each CD is local in the future.

Diffraction lens 2 has phase structure on the 1st 2a of conduct for the optical surface of object lens body 1 opposition side, just can form diffraction light thus.In addition, be tabular surface in the case as the 2nd 2b of the optical surface of object lens body 1 side, can not have influence on imaging.

That kind as shown in Figure 2, it is the middle section CA of central circular and the neighboring area PA on every side of middle section CA that the 1st 2a of diffraction lens 2 is divided into optical axis OA2.Middle section CA has phase structure, and neighboring area PA is a tabular surface.Middle section CA has diffractive for the laser of the wavelength 655nm that DVD uses, but the laser of the wavelength 405nm that uses for BD does not have diffractive.That is; Incide at the laser of the wavelength 655nm that DVD uses under the situation of middle section CA and disperse with the power of regulation because of diffraction effect laser, the next laser of situation that the laser of the wavelength 405nm that uses at BD incides middle section CA and neighboring area PA remain untouched through and do not produce diffraction effect.That is; Under the situation of this embodiment; Through object lens body 1 combination with diffraction lens 2, for DVD with and two kinds of laser using of BD just can carry out interchangeable imaging with desirable precision, and can each laser be read light as the information of each CD or the information recording light is used.

In addition, the optical axis OA2 of said here diffraction lens 2 is so because the 2nd 2b is that tabular surface is consistent with the optical axis of the 2nd 2a.

In addition, on object lens body 1 and diffraction lens 2, be formed with mark M1, the M2 of circular overshooting shape respectively, as the telltale mark of the benchmark that is used for separately optical axis OA1, center that OA2 passes through are positioned each other.

Fig. 3 (a)～(f) is the sectional drawing of explanation concrete example of formed multi-stage type diffraction structure as phase structure on the middle section CA of the 1st 2a that is arranged at diffraction lens 2.This multi-stage type diffraction structure has and the section configuration that comprises optical axis OA2 is set as stair-stepping pattern is concentric circles and arranges; Number to regulation grade face number (in Fig. 3 (a)～(f), being 5 grade faces) makes the structure of ladder displacement one by one with the height corresponding to the exponent number of this grade face number part (is 4 rank) in Fig. 3 (a)～(f), and the situation with laser incident of the wavelength 655nm that uses at DVD issues living diffraction light and do not produce the characteristic that diffraction effect ground does not remain untouched it is seen through in that the situation of the laser incident of wavelength 405nm is next.About this multi-stage type diffraction structure at ISOM ' 03 (INTERNATIONAL SYMPOSIUM ONOPTICAL MEMORY 2003) thus 230 pages～231 pages of technical digests in to some extent record omit detailed explanation here.Fig. 3 (a) and (b) represent that the inclination of each pattern is the example that benchmark becomes unidirectional multi-stage type diffraction structure with optical axis OA2; Fig. 3 (c), (d) are illustrated in the example that periphery is provided with the multi-stage type diffraction structure of phase inversion portion (paraphase portion), and Fig. 3 (e), (f) represent that the inclination of each pattern is become the example of opposite multi-stage type diffraction structure in the outside by phase inversion portion.

In addition; As phase structure; The zigzag diffraction structure or all jumps shown in Fig. 4 (e), (f) that also can be zigzag fashion with the section configuration that comprises optical axis OA2 shown in Fig. 3 (g), (h) and Fig. 4 (a)～(d) are that benchmark becomes unidirectional stepped diffraction structure, perhaps the optical path difference towards from the way, beginning to replace of the jump shown in Fig. 4 (g), (h) is given structure with optical axis OA2, are formed on the middle section CA of the 1st 2a that is arranged at diffraction lens 2.Fig. 3 (g), (h) represent that the inclination of each sawtooth is the example that benchmark becomes unidirectional zigzag diffraction structure with optical axis OA2; Fig. 4 (a) and (b) are illustrated in the example that periphery is provided with the zigzag diffraction structure of phase inversion portion, and Fig. 4 (c), (d) represent that the inclination of each sawtooth is become the example of opposite zigzag diffraction structure in the outside by phase inversion portion.

Turn back to Fig. 1, picture frame 3 is cylindric the 1st and the 2nd fitting portion 4,5 that has the jump shape at two ends; The the 1st and the 2nd reference field 6,7 of ring-type; The 3rd reference field 11 of the diaphragm 10 of ring-type, ring-type and the 3rd fitting portion 12.The the 1st and the 2nd fitting portion the 4, the 5th has the cylinder inner face of jump respectively, and flange (mounting edge) 1f, the 2f of object lens body 1 and diffraction lens 2 fixed along the optical axis vertical direction respectively.The the 1st and the 2nd reference field 6,7 is connected respectively to the 1st and the 2nd fitting portion 4,5 and forms, and for when the installation of object lens body 1 and diffraction lens 2, is used for flange 1f, 2f are carried out reference of reference along optical axis OA1, OA2 direction.The 2nd fitting portion 5 is provided with play (gap) 8.This play 8 can be in the inching to the center is coincide with respect to object lens body 1 of diffraction lens 2.The bonding agent that is formed with the chamfering shape in the end of the 1st and the 2nd fitting portion 4,5 accumulates portion 9.Flange part 1f, the cooperation of 2f periphery of accumulating portion 9 and object lens body 1 and diffraction lens 2 through this bonding agent form V-shaped groove, bonding afterwards or around preventing that bonding agent from spilling in bonding at two lens 1,2.Between the 1st fitting portion 4 and the 2nd fitting portion 5 and the diaphragm 10 that is disposed at picture frame 3 inwalls carry out the cut-out (cut) of the unwanted light of object lens 50 when using or the adjustment of light quantity.The 3rd reference field 11 is that with the optical axis OA1 direction or the relevant reference for installation that tilts, the 3rd fitting portion 12 is the benchmark relevant with the optical axis vertical direction when installing as the retainer of the parts of optical Pickup device etc.

In addition, the 1st of diffraction lens 2 the 2a tilts with respect to object lens body 1 a little.That is the optical axis OA2 of diffraction lens 2 has non-vanishing tiny inclination angle with respect to the optical axis OA1 of object lens body 1.Shape error when this inclination results from the manufacturing of picture frame 3 or manufacturing variation remaining etc. and taking place exaggerates showing in Fig. 1, but littler usually.As above,, then follow in this middle section CA to tilt on direction, to squint simultaneously perpendicular to optical axis OA1 with respect to optical axis OA1 if the 1st 2a of diffraction lens 2 tilts.Such inclination or skew; Do not influence bringing especially because of the relevant optically focused characteristic of laser of the wavelength 405nm that uses with BD that do not receive diffraction at the formed multi-stage type diffraction structure of middle section CA; But the relevant optically focused characteristic of laser of the wavelength 655nm that uses with DVD that receives diffraction because of the multi-stage type diffraction structure then brought to be influenced, and aberration might take place when optically focused.In the object lens 50 of this embodiment; Though details is narrated in the back but is applied effort through the aligning to object lens body 1 and diffraction lens 2; Even if under the situation of diffraction lens 2, also can realize certain above imaging precision with respect to the optical axis OA inclination of object lens body 1.

In addition, the situation that also has optical axis OA1 to tilt because of the foozle of object lens body 1 etc.The optical axis OA2 of diffraction lens 2 also relatively tilts with respect to the optical axis OA1 of object lens body 1 in the case, gets final product so the result handles as the relative tilt of the 1st 2a of diffraction lens 2.

Below, describe with regard to the manufacturing process of the object lens in this embodiment 50.At first, object lens body 1 is installed on picture frame 3.Making the flange surface of object lens body 1 be connected to the 1st reference field 6 injects bonding agent with bonding agent and accumulates portion 9.Thus, object lens body 1 just is fixed on assigned position.At this moment, because remaining bonding agent stays bonding agent and accumulates portion 9, so around just can preventing that bonding agent from spilling in bonding or after bonding.

Then, with picture frame 3 on the object lens body installed 1 a mutually opposed side diffraction lens 2 is installed.Make the flange surface of diffraction lens 2 be connected to the 2nd reference field 7 and carry out the location with object lens body 1.At this moment, it is also bigger slightly than the profile of diffraction lens 2 that the 2nd fitting portion 5 is designed to its internal diameter, and this difference just becomes play 8.Thus, diffraction lens 2 is movable on the direction vertical with respect to optical axis direction, on the optical axis vertical direction, carries out relative location while just can observe opposed object lens body 1.

Behind the location of having carried out diffraction lens 2, bonding agent is injected bonding agent accumulate portion 9.Thus, diffraction lens 2 is just to be able to fix through the state of aiming at.At this moment, because remaining bonding agent stays bonding agent and accumulates portion 9, so around just can preventing that bonding agent from spilling in bonding or after bonding.In addition, diaphragm 10 prevents that in addition bonding agent from getting into the effect of drip when picture frame 3 inside.

Make object lens 50 through above processing.As above-mentioned, object lens 50 is to constitute except that object lens body 1 and three parts that also further used picture frame 3 diffraction lens 2.Thus, just can carry out the relative positioning on the optical axis vertical direction of object lens body 1 and diffraction lens 2 in advance accurately.

In addition, in this explanation, be to establish object lens body 1 formerly about the order of installing, diffraction lens 2 after.This is to observe the convenience in such design in order when the location, to be easy to the diffraction lens less from focal power 2 one sides.But, for example object lens body 1 is being set as under the situation about positioning behind, it is also harmless to change the order of installing.Under the situation that changes erection sequence, play is set in the 1st fitting portion 4 sides.In addition, as other fixing means, for example, can also two lens 1,2 be fixed with respect to picture frame 3 through laser bonding.In addition, not only can also play all be arranged the both sides of diffraction lens 2 and object lens body 1 in diffraction lens 2 sides.

Fig. 5 and Fig. 6 conceptually explain the expanded view of diffraction lens 2 for the state before and after the aligning of object lens body 1.As shown in Figure 5, under the state before aligning, allow the inclination of diffraction lens 2, the optical axis OA2 that establishes diffraction lens 2 with the inboard center IC as the intersection point of the 2nd 2b and optical axis OA2 be fulcrum, with respect to the optical axis OA1 tilt angle theta of object lens body 1.Like this; Even if tilt also not make the imaging characteristic deterioration of object lens 50 for diffraction lens 2; Hope that kind as shown in Figure 6, for example from the laser LL of the optical axis OA1 incident abreast of light source side and object lens body 1 through mark M2 as the heart among the diffraction lens 2, and then; Through mark M1, and advance along optical axis OA1 and to aim at like this as the heart among the object lens body 1.Like this, on optical axis OA1 direction, make object lens body 1 consistent, then no matter how the value of the tiltangle of diffraction lens 2 can both lower the coma aberration that takes place as object lens 50 at least with the center of diffraction lens 2 through utilizing mark M1, M2.As shown in Figure 5, under the state before aligning, squint by distance X on the optical axis vertical direction in the position of two mark M1, M2.This distance X is that d, pitch angle are to utilize following formula X=d (sin θ-sin (θ/n)) to provide after the refractive index of θ and diffraction lens 2 is n at the thickness of establishing diffraction lens 2.Before aligning owing to resulting from this offset X the relevant coma aberration of wavelength 655nm used with DVD takes place; So need make mark M2 on optical axis vertical direction the respective offsets distance X of the mark M1 of object lens body 1 through aligning, come to suppress the generation of coma aberration thus substantively with respect to diffraction lens 2.Such aligning can be realized fairly simplely; Particularly; The object lens body 1 that on one side on optical axis OA1, is installed on picture frame 3 from the drawing left sides is the side configuration diffraction lens 2 in the front of object lens body 1 on one side, and two mark M1, the consistent diffraction lens 2 that makes like this of M2 are moved in the 2nd fitting portion 5 of picture frame 3.Thus, just be able to realize such as state shown in Figure 6, and can guarantee the imaging characteristic of object lens 50.In addition, because the optical axis OA1 direction of object lens body 1 can determine by means of various measuring devices fairly simplely, so wait viewing objective body 1 and diffraction lens 2 by means of microscope from such optical axis OA1 direction that determines.When observing, as long as two mark M1, M2 is consistent in picture aims at like this.

Below, with reference to Fig. 5 and Fig. 6, with regard to the generation of concrete aberration and proofread and correct and describe.In addition, for the ease of explanation, establishing diffraction lens 2 and be with the inboard center IC as the intersection point of the 2nd 2b and optical axis OA2 is fulcrum with respect to object lens body 1 cant angle theta=3 °.Under this state, be these three kinds of the inclinations of the skew of the inclination of the 1st 2a, the 1st 2a, the 2nd 2b with the eccentric error that takes place.The pitch angle of the pitch angle of the 1st 2a and the 2nd 2b is 3 °, and the relevant coma aberration of wavelength 655nm with DVD uses that takes place thus is respectively+105m λ RMS ,-105 λ m λ RMS and cancelled out each other.But, so just be-71m λ RMS for-71m λ RMS as the whole coma aberrations of object lens 50 owing to result from the relevant coma aberration of the wavelength 655nm that uses with DVD of skew of the 1st 2a.In addition, if the refractive index n of the wavelength 655nm that to establish the thickness d of diffraction lens 2 be 0.92mm, diffraction lens 2 uses for DVD is 1.505 then the offset X of the 1st 2a just is 16 μ m.

In addition, if consider to prevent the effect of the influence of back light, the optical effect for incident light of this phase control element (for example for using the dispersing of wavelength light, converging action etc.) then as the angle of inclination preferably more than or equal to 1 ° smaller or equal to 5 °.

The aberration of the constant object lens of using as DVD 50 of former state just will be above マ レ シ ヤ Le boundary, i.e. practical permissible range like this.Being roughly zero aligning with regard to the coma aberration that makes object lens 50 below describes.That kind as shown in Figure 6 is utilized mark M1, M2, make object lens body 1 center (optical axis of object lens body 1 and the intersection point of optical surface) and diffraction lens 2 center (intersection point of the optical axis OA2 of the 1st, the 2nd 2a, 2b and this diffraction lens 2 of diffraction lens 2) about in the optical axis OA1 side of object lens body 1 upwardly extending light path consistent.Thus, just become 0m λ as object lens 50 whole coma aberrations.Thereby, no matter how the value of the refractive index n of the thickness d of the tiltangle of diffraction lens 2, diffraction lens 2 and diffraction lens 2 can both make the coma aberration that takes place as object lens 50 be roughly zero.

(the 2nd embodiment)

Below, describe with regard to the object lens of the 2nd embodiment.The object lens of the 2nd embodiment is out of shape the object lens 50 of the 1st embodiment shown in Figure 1, and is then common with the 1st embodiment as for the part that does not describe especially.

Fig. 7 is the expanded view that is used to explain the object lens of the 2nd embodiment.Under the situation of the object lens 150 of this embodiment, the 2nd of object lens body 1 side the 102b has phase structure among the diffraction lens 102, and the 1st 102a of opposition side is tabular surface.

In addition, identical with the 1st embodiment, because diffraction lens 102 also is that the 1st 102a forms with tabular surface, so the optical axis OA2 of diffraction lens 102 is consistent with the optical axis of the 2nd 102b.

Identical with the situation of the 1st embodiment, establish the optical axis OA1 tilt angle theta of the optical axis OA2 of diffraction lens 102 with respect to object lens body 1.Even if tilt also not make the imaging characteristic deterioration of object lens 150 like this for diffraction lens 102; For example hope that laser LL from the optical axis OA1 incident abreast of light source side and object lens body 1 is through the mark M2 as the heart among the diffraction lens 102; And then; Through mark M1, and advance along optical axis OA1 as the heart among the object lens body 1.Like this, on optical axis OA1 direction, make object lens body 1 consistent, then no matter how the value of the tiltangle of diffraction lens 102 can both lower the coma aberration that takes place as object lens 150 at least with the center of diffraction lens 102 through utilizing mark M1, M2.

Be disposed at the way on the optical axis OA1 of object lens body 1 as mark M2 with diffraction lens 102; The object lens body 1 that on one side on optical axis OA1, is installed on not shown picture frame from the drawing left sides is the side configuration diffraction lens 102 in the front of object lens body 1 on one side, and two mark M1, the consistent diffraction lens 102 that makes like this of M2 are moved in picture frame.Thus, just be able to realize such as state shown in Figure 7, and can guarantee the imaging characteristic of object lens 150.

Below, the concrete example that is roughly zero aligning with regard to the coma aberration that makes object lens 150 describes.That kind as shown in Figure 7 utilizes mark M1, M2 in the prolongation of the optical axis OA1 of object lens body 1, to make the center of diffraction lens 2 consistent.The pitch angle of also establishing the 1st and the 2nd 102a, 102b in the case is 3 °.Under this state; The relevant coma aberration of wavelength 655nm with DVD uses of skew of the 1st 102a of resulting from is 0m λ; The coma aberration of inclination of the 1st 102a of resulting from is+105m λ; The coma aberration of inclination of the 2nd 2b of resulting from is-105m λ, so be 0m λ just as object lens 150 whole coma aberrations.Thereby, no matter how the value of the tiltangle of diffraction lens 102 can both make the coma aberration that takes place as object lens 150 be roughly zero.

(the 3rd embodiment)

Below, describe with regard to the object lens of the 3rd embodiment.The object lens of the 3rd embodiment is out of shape object lens 50 grades of the 1st embodiment shown in Figure 1, and is then common with the 1st embodiment or the 2nd embodiment as for the part that does not describe especially.

Fig. 8 is the cross-sectional side view of the object lens 250 relevant with the 3rd embodiment.Under the situation of this object lens 250, the optical axis OA2 of diffraction lens 202 also has non-vanishing tiny inclination angle with respect to the optical axis OA1 of object lens body 1.But, such inclination be not result from the foozle of picture frame 203 etc. and produce but result from diffraction lens 202 self foozle etc. and produce.Like this if the 1st 202a and the 2nd 202b of diffraction lens 202 tilt; Though then the relevant optically focused of laser to the wavelength 405nm that uses with BD does not bring influence especially; But the relevant optically focused of laser to the wavelength 655nm that uses with DVD brings influence, when optically focused, aberration will take place.Such aberration, identical with the situation of the 2nd embodiment shown in Figure 6 etc., offset through the aligning that utilizes mark M1, M2, even if at the imaging precision that also can realize under the situation that diffraction lens 202 tilts with respect to the optical axis OA1 of object lens body 1 more than certain.

(the 4th embodiment)

Below, describe with regard to the object lens of the 4th embodiment.The object lens of the 4th embodiment is out of shape the object lens 50 of the 1st embodiment shown in Figure 1, and is then common with the 1st embodiment as for the part that does not describe especially.

Fig. 9 is the cross-sectional side view of the object lens 350 relevant with the 4th embodiment.Under the situation of this object lens 350, on picture frame 3, be formed with otch (breach) 303d of the conduct inclination mark of the direction that the optical axis OA2 that is used to represent diffraction lens 2 tilts.Through utilizing this otch 303d just can control, except that the optical characteristics of diffraction lens 2, can also control inclination for seeing through light or catoptrical influence to the vergence direction of diffraction lens 2.In addition, picture frame 3 comprises the 1st embodiment in shape asymmetry situation also comprises situation about deliberately being provided with interior and be not limited to the involuntary situation about causing of foozle etc.Asymmetry in picture frame 3 shapes is under the involuntary situation about causing; The vergence direction that waits to confirm optical axis OA2 through the instrumentation after making is with formation otch 303d; On the other hand; In the asymmetry of picture frame 3 shapes under the situation about deliberately causing, then according to its vergence direction that designs to confirm optical axis OA2 with formation otch 303d.

In addition, the vergence direction that shows optical axis OA2 is not limited to otch 303d and can also adopts and comprise three-dimensional shape, painted etc. at interior various marks.

(the 5th embodiment)

Below, describe with regard to the object lens of the 5th embodiment.The object lens of the 5th embodiment is out of shape the object lens 250 of the 3rd embodiment shown in Figure 8, and is then common with the 3rd embodiment as for the part that does not describe especially.

Figure 10 is the front view (FV) of diffraction lens among the object lens relevant with the 5th embodiment.Under the situation of this object lens, at diffraction lens 2 otch 402d from the conduct inclination mark that is formed with the direction that is used to represent that optical axis OA2 tilts on one's body.Through utilizing this otch 402d, just can control the vergence direction of the 1st 2a etc. of diffraction lens 2, except that the optical characteristics of diffraction lens 2, can also control inclination for seeing through light or catoptrical influence.In addition, diffraction lens 2 comprises the 3rd embodiment in shape asymmetry situation also comprises situation about deliberately being provided with interior and be not limited to involuntary situation about causing such as foozle.Asymmetry in diffraction lens 2 shapes is under the involuntary situation about causing; The vergence direction that waits to confirm optical axis OA2 through the instrumentation after making is with formation otch 402d; On the other hand; In the asymmetry of diffraction lens 2 shapes under the situation about deliberately causing, then according to its vergence direction that designs to confirm optical axis OA2 with formation otch 402d.

In addition, the vergence direction that shows optical axis OA2 is not limited to otch 402d and can also adopts and comprise three-dimensional shape, painted etc. at interior various marks.

(the 6th embodiment)

Figure 11 has diagrammatically represented to pack into the figure of formation of optical Pickup device of the relevant object lens 50,150,250,350 of above-mentioned the 1st～the 5th embodiment.

This optical Pickup device; Have 2 long wavelength semiconductor lasers 61 of the laser (for example using medium wavelength to be 405nm, NA0.85) that the information regeneration of laser (for example using medium wavelength to be 655nm, NA0.60 at DVD) that information regeneration that the 1st CD D1 takes place uses and the 2nd CD D2 uses, promptly can penetrate the mutual different laser of wavelength at BD.Laser from semiconductor laser 61 utilizes object lens 50,150,250,350, and CD D1, D2 as optical information recording medium are shone, and from the reflected light of CD D1, D2, then utilizes object lens 50～350 to carry out optically focused.

At first, under the situation that the 1st CD D1 is regenerated, from the laser of semiconductor laser 61 outgoing wavelength 655nm, the light beam of institute's outgoing sees through collimator 62, polarization beam splitter 63,1/4 wavelength plate 64 and becomes the parallel beam of circularly polarized light.This light beam is converged to the information recording surface MS1 of the 1st CD D1 through object lens 50～350.

On information recording surface MS1 according to the light beam of information concave point (pit) through the ovennodulation back reflection; See through object lens 50～350,1/4 wavelength plate 64 once more; Incide polarization beam splitter 63; Reflect the back at this and give by cylindrical lens (cylinder lenses) 65 and astigmatism, incident on photodetector 67, and utilize its output signal and obtain to attend at the 1st CD D1 the signal that reads of institute's information recorded.

In addition, to detecting because of the caused light quantity of change in shape, the change in location of luminous point changes, and focus (focusings) detects or follows the tracks of detection on photodetector 67.Based on this detection; Be installed in the two-dimensional adjustment device 72 on the retainer 71 that keeps object lens 50～350; Object lens 50～350 is being moved on the optical axis direction so that be imaged on the information recording surface MS1 of the 1st CD D1 from the light beam of semiconductor laser 61, object lens 50～350 is moved on the direction perpendicular to optical axis so that be carried out to picture with the track (track) of regulation from the light beam of this semiconductor laser 61.

On the other hand; Under the situation that the 2nd CD D2 is regenerated; From the laser beam of semiconductor laser 61 outgoing wavelength 405nm, the light beam of institute's outgoing sees through collimator 62, polarization beam splitter 63,1/4 wavelength plate 64 and becomes the parallel beam of circularly polarized light.This light beam is converged at the information recording surface MS2 of the 2nd CD D2 through object lens 50～350.

On information recording surface MS2 according to the light beam of information concave point through the ovennodulation back reflection; See through object lens 50～350,1/4 wavelength plate 64 once more; Incide polarization beam splitter 63; Reflect the back at this and give and astigmatism by cylindrical lens 65, incident on photodetector 67, and utilize its output signal and obtain to attend at the 2nd CD D2 the signal that reads of institute's information recorded.

In addition; Identical with the situation of the 1st CD D1; On photodetector 67 to detecting because of the caused light quantity of change in shape, the change in location of luminous point changes; And focus and detect or follow the tracks of and detect, be installed in the two-dimensional adjustment device 72 on the retainer that keeps object lens 50～350, in order to focus on and track and object lens 50～350 is moved.

In the 6th above embodiment, can use with semiconductor laser 61 and photodetector 67 integrated component after integrated, in the case, just do not need polarization beam splitter 63 etc.Otherwise, can also semiconductor laser 61 be divided into the lasing light emitter of wavelength 655nm and the lasing light emitter of wavelength 405nm, will synthesize with the polarization beam splitter that appends from the laser beam of two laser source.

(the 7th embodiment)

Below, describe with regard to the object lens of the 7th embodiment.The object lens of the 7th embodiment is out of shape the object lens 50 of the 1st embodiment shown in Figure 1, and is then common with the 1st embodiment as for the part that does not describe especially.

Figure 12 is the cross-sectional side view of the object lens 550 relevant with the 7th embodiment.Under the situation of this object lens 550, diffraction lens 502 not only has phase structure on the 1st 502a with respect to object lens body 1 inboard, on the 2nd 502b with respect to object lens body 1 table side, also has phase structure.

The 1st 502a of diffraction lens 502, the laser of the wavelength 655nm that uses for DVD has diffractive, but the laser of the laser of the wavelength 405nm that uses for BD or wavelength 780nm that CD is used does not have diffractive.On the other hand, the 2nd 502b has diffractive for the laser of the wavelength 780nm that CD uses, but the laser of the wavelength 405nm that BD is used or the laser of the wavelength 655nm that DVD uses do not have diffractive.In addition, object lens body 1 designs as object with the laser of the wavelength 405nm that BD uses, is aspheric glass lens or plastic lens.

Laser at the wavelength 655nm that DVD uses incides under the situation of this lens unit 550 from light source side (drawing left side); Laser on the 1st 502a of diffraction lens 502 because of diffraction effect with the suitable power optically focused of regulation or disperse, and the DVD that is converged at the figure right side of face through object lens body 1 is with information recording surface (not shown).In addition; Laser at the wavelength 780nm that CD uses incides under the situation of this lens unit 550 from light source side; Laser on the 2nd 502b of diffraction lens 502 because of diffraction effect with the suitable power optically focused of regulation or disperse, and the CD that is converged at the figure right side of face through object lens body 1 is with information recording surface (not shown).In addition; Laser at the wavelength 405nm that BD uses incides under the situation of this lens unit 550 from light source side; Laser is not passed through by diffraction ground former state in diffraction lens 502,, and the BD that converges at the figure right side of face through object lens body 1 is with information recording surface (not shown).That is; Under the situation of this embodiment; Through object lens body 1 combination, just can carry out interchangeable imaging with each laser that, CD usefulness and BD use with desirable precision, and can each laser be read light as the information of each CD or the information recording light is used DVD with diffraction lens 502.

Figure 13 conceptually explains the expanded view of diffraction lens 502 with respect to the aligning of object lens body 1.As can knowing from figure, allow the inclination of diffraction lens 502, the optical axis OA2 of diffraction lens 502 is with respect to the optical axis OA1 tilt angle theta of object lens body 1.Just must be if diffraction lens 502 tilts then like this with respect to the optical axis OA1 occurrence positions of object lens body 1 not just (dislocation) as at least one side among inboard center (intersection point of the optical axis of the 2nd 502b and the 2nd the 502b) IC of the mark M2 at the center (intersection point of the optical axis of the 1st 502a and the 1st 502a) of the 1st 502a and the 2nd 502b.That is; The 1st 502a carried out with respect to optical axis OA1 under the situation of aiming at; Just occurrence positions is not just with the distance X X=d that yet once explained Fig. 5 (sin θ-sin (θ/n)) from optical axis OA1 at the center of the 2nd 502b; Otherwise the 2nd 502b carried out the situation of aiming at respect to optical axis OA1 under (with reference to the light LL ' among Figure 13), just in the opposite direction occurrence positions be not just with the distance X of mistake illustrated in fig. 5 from optical axis OA1 at the center of the 1st 502a.

In addition, as can knowing, in this example, on the 1st 502a, the 2nd 502b, be formed with phase structure respectively, and the optical axis OA2 of the optical axis of each face and diffraction lens 502 is consistent from Figure 13.

Generally speaking, because of the center of the 1st 502a or the 2nd 502b departing from the coma aberration that produces from the light LL that optical axis OA1 has been prolonged, reciprocal proportional with the substrate thickness of 3 powers of the NA value of object lens 550, CD and Wavelength of Laser.Here, the 1st 502a for example is that DVD uses, NA0.60, substrate thickness 0.6mm, wavelength 655nm, and the 2nd 502b for example is that CD uses, NA0.45, substrate thickness 1.2mm, wavelength 780nm.Thereby the coma aberration that produces in the malposition of establishing the 2nd 502b that uses because of CD is 1 o'clock, and the coma aberration that the malposition of the 1st 502a that uses because of DVD produces just becomes about 2～6 times.Can know from this point and this means under the offset of the 1st 502a and situation that the offset of the 2nd 502b equates; The off-centre of the 1st 502a just becomes the 2nd 502b to the contribution degree of coma aberration off-centre is to about 2～6 times of the coma aberration contribution degree, and the offset that reduces by the 1st 502a compared with the offset that reduces by the 2nd 502b seek overall performance improve aspect on meaningful.

On the other hand, under the situation that diffraction lens 502 tilts, can't avoid a certain side in the off-centre of eccentric or the 2nd 502b of the 1st 502a.That is, under the situation at the center that has disposed the 1st 502a on the light LL that advances along optical axis OA1 (being that the center prolongs light path), the center that just can't on light LL, dispose the 2nd 502b.Otherwise, with the center configuration of the 2nd 502b under the situation on the light LL, just can't be on light LL with the center configuration of the 1st 502a.For this reason; In this embodiment; Through in the 1st 502a, being formed centrally mark M2 and this mark M2 being configured on the light LL, just will be taken as Min. because of the 1st coma aberration that 502a produces that DVD uses, also allow the 2nd coma aberration of using because of CD that 502b produces simultaneously.That is, shown in figure 13, make the center of object lens body 1 and the light path mutually consistent attenuating of seeking as a whole aberration of center about extending of diffraction lens 502 through utilizing mark M1, M2 in the optical axis OA1 of object lens body 1 direction.

Figure 14 has diagrammatically represented to pack into the figure of formation of optical Pickup device of object lens shown in Figure 13 550.

In this optical Pickup device; Laser from each semiconductor laser 61B, 61D, 61C utilizes object lens 550 to be irradiated to CD DB, DD, DC as optical information recording medium; Reflected light from each CD DB, DD, DC utilizes shared object lens 550 to put together, and finally is imported into each photodetector 67B, 67D, 67C.

Here; The laser (for example BD usefulness, wavelength 405nm, NA0.85) that the information regeneration of the 1st CD DB is used takes place in the 1st semiconductor laser 61B; The laser (for example DVD usefulness, wavelength 655nm, NA0.60) that the information regeneration of the 2nd CD DD is used takes place in the 2nd semiconductor laser 61D, and the laser (for example CD usefulness, wavelength 780nm, NA0.54) that the information regeneration of the 3rd CD DC is used takes place the 3rd semiconductor laser 61C.In addition; The 1st photodetector 67B attendes institute's information recorded with the 1st CD DB and detects as light signal (for example BD with, wavelength 405nm); The 2nd photodetector 67D attendes institute's information recorded with the 2nd CD DD and detects as light signal (for example DVD with, wavelength 655nm), and the 3rd photodetector 67C attendes institute's information recorded with the 3rd CD DC and detects as light signal (for example CD with, wavelength 780nm).

At first, under the situation that the 1st CD DB is regenerated, from the 1st semiconductor laser 61B outgoing laser of wavelength 405nm for example, the light beam of institute's outgoing sees through collimator 62B, polarization beam splitter 63B and becomes parallel beam.After this light beam sees through other polarization beam splitter 64D, 64C, converge to the information recording surface MB of the 1st CD DB by object lens 550.

On information recording surface MB according to the light beam of information concave point through the ovennodulation back reflection; See through object lens 550 etc. once more; Incide polarization beam splitter 63B; Reflect the back at this and give and astigmatism, go up incident, and utilize its output signal and obtain the signal that reads that the 1st CD DB attendes institute's information recorded to the 1st photodetector 67B by cylindrical lens 65B.

In addition, to detecting because of the caused light quantity of change in shape, the change in location of luminous point changes, and focus (focusings) detects or follows the tracks of detection on the 1st photodetector 67B.Based on this detection; Be installed in the two-dimensional adjustment device 72 on the retainer 71 that keeps object lens 550; Object lens 550 is being moved on the optical axis direction so that image on the information recording surface MB of the 1st CD DB from the light beam of the 1st semiconductor laser 61B, object lens 550 is moved on the direction perpendicular to optical axis so that be carried out to picture with the track of regulation from the light beam of the 1st semiconductor laser 61B.

Then, under the situation that the 2nd CD DD is regenerated, from the 2nd semiconductor laser 61D outgoing laser of wavelength 655nm for example, the light beam of institute's outgoing sees through collimator 62D, polarization beam splitter 63D and becomes parallel beam.After this light beam sees through other polarization beam splitter 64D, 64C, converge to the information recording surface MD of the 2nd CD DD by object lens 550.

On information recording surface MD according to the light beam of information concave point through the ovennodulation back reflection; See through thing lens unit 550 etc. once more;, polarization beam splitter 64D incides polarization beam splitter 63D after reflecting; Reflect the back at this and give and astigmatism, go up incident, and utilize its output signal and obtain the signal that reads that the 2nd CD DD attendes institute's information recorded to the 2nd photodetector 67D by cylindrical lens 65D.

In addition; Identical with the situation of the 1st CD DB; On the 2nd photodetector 67D to detecting because of the caused light quantity of change in shape, the change in location of luminous point changes; The line focusing of going forward side by side detects or follows the tracks of and detect, and is installed in the two-dimensional adjustment device 72 that the retainer that keeps object lens 550 is assembled, in order to focus on and track and object lens 550 is moved.

Then; Under the situation that the 3rd CD DC is regenerated; From the 3rd semiconductor laser 61C outgoing laser of wavelength 780nm for example, the light beam of institute's outgoing sees through collimator 62C, polarization beam splitter 63C becomes parallel beam after in polarization beam splitter 64C, reflecting.This light beam is converged to the information recording surface MC of the 3rd CD DC by object lens 550.

On information recording surface MC according to the light beam of information concave point through the ovennodulation back reflection; See through object lens 550 etc. once more; With inciding polarization beam splitter 63C after the polarization beam splitter 64C reflection; Reflect the back at this and give and astigmatism, go up incident, and utilize its output signal and obtain to attend the signal that reads of institute's information recorded at the 3rd CD DC to the 3rd photodetector 67C by cylindrical lens 65C.

In addition; Identical with the situation of the 1st and the 2nd CD DB, DD; On the 3rd photodetector 67C to detecting because of the caused light quantity of change in shape, the change in location of luminous point changes; The line focusing of going forward side by side detects or follows the tracks of and detect, and is installed in two-dimensional adjustment device 72 on the retainer that keeps object lens 550 in order to focus on and track and object lens 550 is moved.

In addition, though in above embodiment, the 1st 502a that establishes diffraction lens 502 is that DVD uses, the 2nd 502b is CD usefulness, also can establish the 1st 502a and is CD and use and establish the 2nd 502b and use as DVD.In the case, just with the center configuration of the 2nd 502b on the light LL that advances along optical axis OA1.

(the 8th embodiment)

Below, describe with regard to the object lens of the 8th embodiment.The object lens of the 8th embodiment is out of shape the object lens 550 of the 7th embodiment shown in Figure 12, and is then common with the 7th embodiment as for the part that does not describe especially.

Figure 15 is the cross-sectional side view of the object lens 650 relevant with the 8th embodiment.Under the situation of this object lens 650, in diffraction lens 602, not only in the 1st 502a, be formed centrally mark M2 ' and also in the 2nd 502b, be formed centrally mark M2 ".

Figure 16 conceptually explains the expanded view of diffraction lens 602 with respect to the aligning of object lens body 1.As can knowing from figure, allow the inclination of diffraction lens 602, the optical axis OA2 of diffraction lens 602 is with respect to the optical axis OA1 tilt angle theta of object lens body 1.If diffraction lens 602 tilts then as the mark M2 ' at the center of the 1st 502a with as the mark M2 at the center of the 2nd 502b like this " in the just inevitable optical axis OA1 occurrence positions with respect to object lens body 1 of at least one side not just (dislocation).

As also once explaining in the 7th embodiment; Generally speaking, because of as the mark M2 ' at the center of the 1st 502a or as the mark M2 at the center of the 2nd 502b " substrate thickness, Wavelength of Laser reciprocal proportional of departing from 3 powers, the CD of the NA value of the coma aberration that produces and object lens 650 from the light LL that optical axis OA1 has been prolonged.So as long as the offset of the 1st 502a and the offset of the 2nd 502b are suited to adjust; Just can make result from the 1st 502a off-centre coma aberration with result from the coma aberration approximate equality ground of off-centre of the 2nd 502b and carry out balance, perhaps, can also by desirable ratio set result from the 1st 502a off-centre coma aberration with result from the coma aberration of off-centre of the 2nd 502b.

Figure 17 representes to observe the microscopic field of view MF behind the lens unit 650 shown in Figure 15 from light source side.On optical axis OA1, be installed on one side the object lens body 1 of the picture frame 3 of lens unit 650 from the drawing left sides; Diffraction lens 602 is configured in the front side of object lens body 1 on one side, and diffraction lens 602 is moved in the 2nd fitting portion 5 of picture frame 3 so that mark M1 is positioned at position two mark M2 ', M2 " between.For example want to make result from the 1st 502a off-centre coma aberration with result under the situation of coma aberration approximate equality balanced of off-centre of the 2nd 502b, diffraction lens 602 is aimed at so that mark M1 is positioned at the off-centre of the 1st 502a that the off-centre of the contribution degree of coma aberration and the 2nd 502b is got final product the position that the inverse of the ratio of the contribution degree of coma aberration carries out branch.Here, the 1st 502a for example is that DVD uses, NA0.60, substrate thickness 0.6mm, wavelength 655nm, and the 2nd 502b for example is that CD uses, NA0.45, substrate thickness 1.2mm, wavelength 780nm.Thereby the coma aberration that produces in the malposition of establishing the 2nd 502b that uses because of CD is 1 o'clock, and the coma aberration that the malposition of the 1st 502a that uses because of DVD produces just becomes about 2～6 times.Thus; Can know for make result from the 1st 502a off-centre coma aberration with result from the coma aberration approximate equality balanced of off-centre of the 2nd 502b; For example under the coma aberration that the malposition of the 1st 502a that uses because of DVD causes is 2 times situation, make mark M1 be present in two mark M2 ', M2 " between and from mark M2 ' 0.33D, from mark M2 " 0.66 position gets final product.Through being that benchmark is adjusted two mark M2 ', M2 with mark M1 like this " the position, just can suitably adjust and result from the generation balance of coma aberration of inclination of two sides 502a, 502b.

(the 9th embodiment)

Be the figure that diagrammatically representes the formation of the optical Pickup device relevant below with the 9th embodiment.This optical Pickup device utilizes the object lens 550 relevant with the 7th embodiment shown in Figure 12.

Figure 18 is the expanded view that the state after diffraction lens 502 is with respect to the aligning of object lens body 1 conceptually is described.As can knowing from figure, allow the inclination of diffraction lens 502, the optical axis OA2 of diffraction lens 502 is with respect to the optical axis OA1 tilt angle theta of object lens body 1.As also once explaining in the 7th embodiment; Generally speaking; Because of the center of the 1st 502a or the 2nd 502b departing from the coma aberration that produces from the light LL that optical axis OA1 has been prolonged, reciprocal proportional with the substrate thickness of 3 powers of the NA value of object lens 550, CD and Wavelength of Laser.If explain with concrete example; Then can know and this means under the offset of the 1st 502a and situation that the offset of the 2nd 502b equates; The off-centre of the 1st 502a just becomes the 2nd 502b to the contribution degree of coma aberration off-centre is to about 2～6 times of the coma aberration contribution degree, and the offset that reduces by the 1st 502a compared with the offset that reduces by the 2nd 502b in that to seek overall performance meaningful aspect improving.Thereby, through in the 1st 502a, being formed centrally mark M2 and this mark M2 being configured on the light LL, just will be taken as Min. because of the 1st coma aberration that 502a produces that DVD uses, also allow the 2nd coma aberration of using because of CD that 502b produces simultaneously.On the other hand, if can also lower, then can greatly reduce the aberration of object lens 550 with the coma aberration that additive method will produce because of the off-centre of the 2nd 502b.Based on such purpose, the light source position through wavelength 780nm that CD is used is disposed at the position that the light source position used from BD or DVD leaves, and lowers the coma aberration that the off-centre because of the 2nd 502b produces.

Figure 19 is the figure of formation that diagrammatically representes the optical Pickup device of this embodiment.This optical Pickup device, packed into Figure 12, the object lens shown in 18 550 have same structure with the optical Pickup device relevant with the 6th embodiment shown in Figure 11 except that light source.

Figure 20 is the figure that the vertical section structure of 3 long wavelength semiconductor lasers of in optical Pickup device shown in Figure 19, being assembled 761 is described.As can knowing from figure, be formed with the 1st and the 2nd laser diode 761a, the 761b of 2 layers of structure in the left part of semiconductor laser chip 761X, be formed with the 3rd independent laser diode 761 in the right portions of semiconductor laser 761.The laser that the information regeneration of the 1st CD DB uses (for example BD with, wavelength 405nm) takes place in the 1st laser diode 761a; The laser that the information regeneration of the 2nd CD DD uses (for example DVD with, wavelength 655nm) takes place in the 2nd laser diode 761b, and the laser that the information regeneration of the 3rd CD DC uses (for example CD with, wavelength 780nm) takes place the 3rd laser diode 761c.As illustrating, the 1st and the 2nd laser diode 761a, 761b aim at along optical axis OA and are configured, and are configured but the 3rd laser diode 761c then leaves distance, delta X from optical axis OA.Coma aberration will take place in its result when the imaging of the 3rd laser diode 761c, but such coma aberration, the coma aberration size in the opposite direction that produces like the off-centre because of the 2nd 5b2b in the illustrated mistake of Figure 18 is identical.That is, just approach zero at 405nm that BD uses, 655nm that DVD uses, 780nm that CD uses in all by the coma aberration of object lens 550 formed focal points, and reach good aberration correction.

(the 10th embodiment)

Figure 21 is the cross-sectional side view of the object lens 50 relevant with the 10th embodiment.Under the situation of this object lens 50, have interchangeability for the mutual different three kinds of CDs (for example CD, DVD and BD) of specification (recording density etc.), can on these CDs, constitute on recording/reproducing information ground.In addition, this object lens 50 has convergence forms focal point from the laser (make and use up) of not shown light source and on not shown CD the object lens body 1 as object optical element; Be used to form diffraction light as the diffraction lens 2 of phase control element and be used for the integrated picture frame 3 that fixes of object lens body 1 and diffraction lens 2 as the barrel shape of holding components.Here, object lens body 1 is for example formed by materials such as glass, and diffraction lens 2 forms with picture frame 3 for example adds the fine glass particle of tens of number percents by plastics or in plastics material.

Object lens body 1 is the big projection of the 1st 1a of diffraction lens 2 sides and the 2nd the aspheric biconvex lens that 1b relatively is formed flatly of CD side (figure right side of face), the regulation place that will converge at each CD respectively through the diffraction light or the non-diffracted light corresponding to 3 different wave lengths of diffraction lens 2.In addition, object lens body 1 has the intrinsic optical axis OA0 by the 1st 1a and the 2nd 1b defined as primary optical axis.

Diffraction lens 2 just can form making of specific wavelength used up the diffraction light of restraining or dispersing with desirable degree through having phase structure respectively as the 1st 2a of the optical surface inboard with respect to object lens body 1 with on as the 2nd 2b with respect to the optical surface of object lens body 1 table side.

If specifically describe, the laser that is exactly the wavelength 655nm that uses for DVD of the 1st 2a of diffraction lens 2 has diffractive, but the laser of the wavelength 405nm that uses for BD or the laser of the wavelength 780nm that CD uses do not have diffractive.On the other hand, the 2nd 2b has diffractive for the laser of the wavelength 780nm that CD uses, but the laser of the wavelength 405nm that uses for BD or the laser of the wavelength 655nm that DVD uses do not have diffractive.In addition, the laser of the wavelength 405nm that uses with BD of object lens body 1 designs as object.

Laser at the wavelength 655nm that DVD uses incides under the situation of this object lens 50 from light source side (drawing left side); Laser on the 1st 2a of diffraction lens 2 because of diffraction effect with the regulation suitable power optically focused or disperse, the DVD that is converged to the figure right side of face through object lens body 1 is with information recording surface (not shown).In addition; Laser at the wavelength 780nm that CD uses incides under the situation of this object lens 50 from light source side; Laser on the 2nd 2b of diffraction lens 2 because of diffraction effect with the regulation suitable power optically focused or disperse, the CD that is converged to the figure right side of face through object lens body 1 is with information recording surface (not shown).In addition, incide from light source side under the situation of this object lens 50 at the laser of the wavelength 405nm that BD uses, laser diffraction lens 2 do not receive diffraction and remain untouched through, the BD that is converged to the figure right side of face through object lens body 1 is with information recording surface (not shown).That is; Under the situation of this embodiment; Combination through object lens body 1 and diffraction lens 2 can to CD with, DVD with and each laser of using of BD carry out interchangeable imaging with desirable precision, and can each laser be read light as the information of each CD or the information recording light is used.

In addition, on object lens body 1 and diffraction lens 2, be formed with mark M1, the M2 of circular overshooting shape respectively, as the telltale mark of the benchmark that is used for separately optical axis OA1, center that OA2 passes through are positioned each other.

Figure 22 (a)～(f) is the sectional drawing of explanation concrete example of formed multi-stage type diffraction structure as phase structure on the 1st 2a of diffraction lens 2.This multi-stage type diffraction structure has and the section configuration that comprises optical axis OA1 is set as stair-stepping pattern is concentric circles and arranges; Number to regulation grade face number (in Figure 22 (a)～(f), being 5 grade faces) makes the structure of ladder displacement one by one with the height corresponding to the exponent number (is 4 rank) of this grade face number part in Figure 22 (a)～(f), and the situation with laser incident of the wavelength 655nm that uses at DVD issues living diffraction light and do not produce the characteristic that diffraction effect ground does not remain untouched it is seen through in that the situation of the laser incident of wavelength 405nm, 780nm is next.About this multi-stage type diffraction structure at ISOM ' 03 (INTERNATIONAL SYMPOSIUM ON OPTICALMEMORY 2003) thus 230 pages～231 pages of technical digests in to some extent record omit detailed explanation here.In the above; Figure 22 (a) and (b) represent that the inclination of each pattern is the example that benchmark becomes unidirectional multi-stage type diffraction structure with optical axis OA1; Figure 22 (c), (d) are illustrated in the example that periphery is provided with the multi-stage type diffraction structure of phase inversion portion (paraphase portion), and Figure 22 (e), (f) represent that the inclination of each pattern is become the example of opposite multi-stage type diffraction structure in the outside by phase inversion portion.

In addition; As phase structure; The zigzag diffraction structure or all jumps shown in Figure 23 (e), (f) that also can be zigzag fashion with the section configuration that comprises optical axis OA1 shown in Figure 22 (g), (h) and Figure 23 (a)～(d) are that benchmark becomes unidirectional stepped diffraction structure, perhaps the optical path difference towards from the way, beginning to replace of the jump shown in Figure 23 (g), (h) is given structure with optical axis OA1, are formed on the 1st 2a of diffraction lens 2.Figure 22 (g), (h) represent that the inclination of each sawtooth is the example that benchmark becomes unidirectional zigzag diffraction structure with optical axis OA1; Figure 23 (a) and (b) are illustrated in the example that periphery is provided with the zigzag diffraction structure of phase inversion portion, and Figure 23 (c), (d) represent that the inclination of each sawtooth is become the example of opposite zigzag diffraction structure in the outside by phase inversion portion.

More than be formed in the explanation of the phase structure on the 1st 2a of diffraction lens 2, on the 2nd 2b of diffraction lens 2, also be formed with same phase structure.But at formed phase structure on the 1st 2a and formed phase structure on the 2nd 2b, its pattern or size are different, and the diffraction of the laser that laser of using for CD or DVD use is different.That is, have under the situation of the laser incident of the wavelength 780nm that CD uses diffraction light does not take place, at wavelength 405nm, remaining untouched under the situation of the laser incident of 655nm sees through it and the characteristic of diffraction effect can not take place.In addition, formed phase structure is the state of mutual dislocation with formed phase structure on the 2nd 2b on the 1st 2a of diffraction lens 2.Figure 24 is the figure of the malposition of explanation each face 2a of constituting diffraction lens 2,2b.With respect to the whole vertical optical axis OA1 of the 1st 2a is through the 1st secondary optical axis of the central point of formed phase structure on the 1st 2a of diffraction lens 2, on the central point of this phase structure, is formed with mark M2.In addition, be the 2nd secondary optical axis with respect to the whole vertical optical axis OA2 of the 2nd b of diffraction lens 2 through the central point of formed phase structure on the 2nd 2b of diffraction lens 2.Under the situation of this embodiment, these optical axises OA1, OA2 are parallel to each other, separate with predetermined distance.Its result as after state, tilt through on the AB direction, making diffraction lens 2, even if the 1st 2a produces dislocation relatively with the 2nd 2b on perpendicular to the direction of optical axis OA0, the relative dislocation counteracting that the result also can be such is with the generation of inhibition coma aberration.

Manufacturing approach with regard to diffraction lens 2 discussed above describes simply; Diffraction lens 2 is for example made through mold formed, can the phase structure of jump structure that on the profile corresponding to a pair of shaping die of the 1st 2a and the 2nd 2b, should form etc. be misplaced in advance.In addition, through so that form cavity (die cavity), just can access like such diffraction lens 2 shown in Figure 24 waits corresponding to the corresponding state that has carried out relative dislocation of relative magnitude of misalignment of a pair of shaping die of the 1st 2a and the 2nd 2b and optical axis OA1, OA2.And then, prepare transparent plectane as the mother metal of diffraction lens 2, after applying the UV hardening resin in right amount, carry out pressing mold on its two sides, just can access the 1st 2a and the 2nd 2b.In the case; Make corresponding to a pair of forging die (pressing mold) of the 1st 2a and the 2nd 2b to push the mother metal of diffraction lens 2 with the corresponding state that has carried out relative dislocation of the relative magnitude of misalignment of optical axis OA1, OA2, irradiation UV light makes the sclerosis of UV hardening resin under this state.Just can access the diffraction lens 2 shown in Figure 24 etc. if remove a pair of forging die.

Turn back to Figure 21, picture frame 3 is cylindric the 1st and the 2nd fitting portion 4,5 that has the jump shape at two ends; The the 1st and the 2nd reference field 6,7 of ring-type; The 3rd reference field 11 of the diaphragm 10 of ring-type, ring-type and the 3rd fitting portion 12.The the 1st and the 2nd fitting portion the 4, the 5th has the cylinder inner face of jump respectively, and flange 1f, the 2f of object lens body 1 and diffraction lens 2 fixed along the vertical direction of optical axis OA0 respectively.The the 1st and the 2nd reference field 6,7 is connected respectively to the 1st and the 2nd fitting portion 4,5 and forms, and for when the installation of object lens body 1 and diffraction lens 2, is used for flange 1f, 2f are carried out reference of reference along optical axis OA0 direction.Wherein be provided with play (gap) 8 in the 2nd fitting portion 5 upper edge optical axis vertical direction.This play 8 can be in the inching to the center is coincide with respect to object lens body 1 of diffraction lens 2.The bonding agent that is formed with the chamfering shape in the end of the 1st and the 2nd fitting portion 4,5 accumulates portion 9.Flange part 1f, the cooperation of 2f periphery of accumulating portion 9 and object lens body 1 and diffraction lens 2 through this bonding agent form V-shaped groove, bonding afterwards or around preventing that bonding agent from spilling in bonding at two lens 1,2.Between the 1st fitting portion 4 and the 2nd fitting portion 5 and the diaphragm 10 that is disposed at picture frame 3 inwalls carry out the cut-out of the unwanted light of object lens 50 when using or the adjustment of light quantity.The 3rd reference field 11 is that with the optical axis OA0 direction or the relevant reference for installation that tilts, the 3rd fitting portion 12 is benchmark relevant with the optical axis vertical direction when installing as the retainer of the parts of optical Pickup device etc.

In addition, in picture frame 3, the 2nd reference field 7 with diffraction lens 2 is aimed in optical axis OA0 direction tilts along the AB direction with respect to the 1st reference field 6 that object lens body 1 is aimed in optical axis OA0 direction a little.Its result, the 1st 2a and the 2nd 2b of diffraction lens 2 tilt on the AB direction with respect to object lens body 1 a little.When carrying out instrumentation at the imaging characteristic to object lens 50, preventing simply lowly needs such inclination because of the back light from diffraction lens 2 makes interference image disorder or its contrast.That is; Through being tilted a little, diffraction lens 2 just can prevent to incide imageing sensor of interferometer etc. from the back light (from the reflected light of diffraction pattern self or its peripheral flat site) of the 1st 2a or the 2nd 2b; The noise of back light of resulting from just is difficult to get into the instrumentation image, so just can make the instrumentation high precision int about the imaging characteristic of object lens 50.Certainly will when the optical Pickup device of such lens unit has been adopted in use, also can prevent to incide optical sensor, can also prevent influence regenerated signal etc. from the back light of diffraction lens 2.In addition, show though in Figure 21, exaggerate, the inclination of diffraction lens 2 is littler usually, for example at 3 ° below the degree.As above,, then follow in this 1st 2a or the 2nd 2b to tilt, on direction, squint simultaneously perpendicular to optical axis OA0 with respect to optical axis OA0 if diffraction lens 2 tilts.Such inclination or skew; The relevant optically focused characteristic of laser of the wavelength 405nm that uses with BD that do not receive diffraction because of diffraction patterns such as multi-stage type diffraction structures do not brought especially to be influenced; But the relevant optically focused characteristic of each laser of the wavelength 655nm that the wavelength 780nm that uses with CD that receives diffraction because of such diffraction pattern or DVD are used then brings and influences, and aberration might take place when optically focused.For this reason, in the object lens 50 of this embodiment, as in that also explanation once is such among Fig. 4, optical axis OA1 and the optical axis OA2 of the central point through the 2nd 2b of the central point of the 1st 2a through diffraction lens 2 are misplaced abreast.Like this, misplace, on the aligning of diffraction lens 2, apply effort simultaneously, even if the imaging precision more than also can reaching necessarily under the situation of diffraction lens 2 with respect to the optical axis OA0 inclination of object lens body 1 for object lens body 1 through deliberately making two sides 2a, 2b.

On picture frame 3, be formed with the otch 3d as azimuth mark of the AB direction of expression the 2nd reference field 7 relative the 1st reference fields 6 inclinations.In addition, on diffraction lens 2, also be formed with the otch 2d that is used to represent to make the AB direction that this diffraction lens 2 tilts as azimuth mark.Through utilizing these otch 2d, 3d just can set the vergence direction of diffraction lens 2 for desirable direction, and can suitably control the influence of inclination for the optical characteristics of diffraction lens 2.

In addition, the vergence direction that shows diffraction lens 2 is not limited to otch 2d, 3d and can also adopts and comprise three-dimensional shape, painted etc. at interior various marks.In addition, can also on diffraction lens 2 or picture frame 3, replace otch 2d, 3d and paste the mark of sheet.

Below, describe with regard to the manufacturing process of the object lens in this embodiment 50.At first, object lens body 1 is installed on picture frame 3.Making the flange surface of object lens body 1 be connected to the 1st reference field 6 injects bonding agent with bonding agent and accumulates portion 9.Thus, object lens body 1 just is fixed on assigned position.At this moment, because remaining bonding agent stays bonding agent and accumulates portion 9, so around just can preventing that bonding agent from spilling in bonding or after bonding.

Then, with picture frame 3 on the object lens body installed 1 relative opposite side diffraction lens 2 is installed.Under the consistent state in the orientation that makes otch 2d, 3d, make the flange surface of diffraction lens 2 be connected to the 2nd reference field 7 and carry out the location with object lens body 1.At this moment, it is also bigger slightly than the profile of diffraction lens 2 that the 2nd fitting portion 5 is designed to its internal diameter, and this difference just becomes play 8.Thus, diffraction lens 2 is movable on the optical axis vertical direction, on the optical axis vertical direction, carries out relative location while just can observe opposed object lens body 1.

Behind the location of having carried out diffraction lens 2, bonding agent is injected bonding agent accumulate portion 9.Thus, diffraction lens 2 is just to be able to fix through the state of aiming at.At this moment, because remaining bonding agent stays bonding agent and accumulates portion 9, so around just can preventing that bonding agent from spilling in bonding or after bonding.In addition, diaphragm 10 prevents that in addition bonding agent from getting into the effect of drip when picture frame 3 inside.

Make object lens 50 through above processing.As above-mentioned, object lens 50 is to constitute except that object lens body 1 and three parts that also further used picture frame 3 diffraction lens 2.Thus, just can carry out the relative positioning on the optical axis vertical direction of object lens body 1 and diffraction lens 2 in advance accurately.

In addition, in this explanation, be to establish object lens body 1 formerly about the order of installing, diffraction lens 2 after.This is to observe the convenience in such design in order when the location, to be easy to the diffraction lens less from focal power 2 one sides.But, for example object lens body 1 is being set as under the situation about positioning behind, it is also harmless to change the order of installing.Under the situation that changes erection sequence, play is set in the 1st fitting portion 4 sides.In addition, as other fixing means, for example, can also two lens 1,2 be fixed with respect to picture frame 3 through laser bonding.In addition, not only can also play all be arranged the both sides of diffraction lens 2 and object lens body 1 in diffraction lens 2 sides.

Figure 25 and Figure 26 conceptually explain the expanded view of diffraction lens 2 for the state before and after the aligning of object lens body 1.Shown in figure 25; Under the state before aligning; Diffraction lens 2 is forced in the AB direction, establish diffraction lens 2 the 1st 2a intrinsic optical axis OA1 be fulcrum with rotation center RC as the intersection point of the 2nd 2b and optical axis OA1, with respect to the optical axis OA0 tilt angle theta of object lens body 1.In the case; Even if tilt also not make the imaging characteristic deterioration of object lens 50 for diffraction lens 2; Hope that kind shown in figure 26; For example from the laser LL of the optical axis OA0 incident abreast of light source side and object lens body 1 mark M2 through the heart (intersection point of the optical axis OA1 of the 1st 2a and the 1st 2a) among the 1st 2a that is equivalent to diffraction lens 2, through the central point C2 (intersection point of the optical axis OA2 of the 2nd 2b and the 2nd 2b) of the 2nd 2b, and then; Through being equivalent to the mark M1 of the heart among the object lens body 1, and advancing along optical axis OA1 and to aim at like this.Like this; Through utilizing mark M1, M2 on optical axis OA0 direction, to make the central point of each face 2a, 2b of the central point of object lens body 1 and diffraction lens 2 consistent, then no matter how the value of the tiltangle of diffraction lens 2 can both lower the coma aberration that takes place as object lens 50 at least.

Shown in figure 25, under the state before aligning, squint by distance X on the vertical direction of primary optical axis OA0 in the position of two mark M1, M2.This distance X is that d, pitch angle are to utilize following formula X=d (sin θ-sin (θ/n)) after the refractive index of θ and diffraction lens 2 is n at the thickness of establishing diffraction lens 2 ... (1) provides.Before aligning owing to resulting from this offset X the relevant coma aberration of wavelength 655nm used with DVD takes place; So need make the mark M1 of object lens body 1 through aligning; As after state with respect to mark M2 respective offsets distance X on the optical axis vertical direction of diffraction lens 2, come to suppress the generation of the relevant coma aberration of the wavelength 655nm that uses with DVD thus substantively.Such aligning can be realized fairly simplely; Particularly; The object lens body 1 that on one side on optical axis OA0, is installed on picture frame 3 from the drawing left sides is the side configuration diffraction lens 2 in the front of object lens body 1 on one side, and two mark M1, the consistent diffraction lens 2 that makes like this of M2 are moved in the 2nd fitting portion 5 of picture frame 3.Thus, just be able to realize that completion object lens body 1 is aimed at diffraction lens 2 such as state shown in Figure 26.In addition, because the optical axis OA0 direction of object lens body 1 can determine by means of various measuring devices fairly simplely, so wait viewing objective body 1 and diffraction lens 2 by means of microscope from such optical axis OA0 direction that determines.When observing, as long as two mark M1, M2 is consistent in picture aims at like this.

As above, the mark M1 of object lens body 1 is being involuted under the situation into the state of Figure 26 at the enterprising line position of optical axis vertical direction with respect to the mark M2 of diffraction lens 2; The generation of the coma aberration that the wavelength 655nm that not only can suppress to use with DVD is relevant can also suppress the generation of the relevant coma aberration of the wavelength 780nm that uses with CD substantively.Specifically describe, then the mark M2 as the central point of the 1st 2a is optically aimed at the central point C2 of the 2nd 2b through dislocation at the optical axis OA1 of the diffraction lens 2 of the illustrated that kind of Figure 24, OA2.That is, prolong at the center that the optical axis OA0 through object lens body 1 extends and not only can dispose the 2nd 2 the central point C2 that can also dispose diffraction lens 2 as the mark M2 of the central point of the 1st 2a of diffraction lens 2 on the light path.In order to realize this aligning, the 1st 2a1 and the 2nd 2b of diffraction lens 2 have dislocation in advance on the AB direction.Such magnitude of misalignment offsets the influence of the inclination of diffraction lens 2, and with appended in above-mentioned formula (1) and offset X consistent.That is; The optics dislocation of the optical axis OA0 direction that takes place because of the inclination of diffraction lens 2 is consistent with offset X; In order such offset X to be offseted and to adopt each the face 2a that makes diffraction lens 2, the central point of 2b on the AB direction, to carry out the structure of inverse offset, just can realize thus with respect to object lens body the 1, the 1st and the 2nd aligning that 2a, 2b are the optical axis vertical direction of diffraction lens 2.Thus, just can the imaging characteristic of object lens 50 be made as less high-precision such as coma aberration.

Figure 27 representes to be used for the interferometer of the optical characteristics (particularly being corrugated aberration etc.) of instrumentation object lens shown in Figure 21 50.This interferometer is made up of the interferometer of Tai Man-Green (Twyman-Green) formula, has light supply apparatus 62 as optical system, collimator lens 63; Beam splitter (beam splitter) 64; Checked object is with platform 65, reference plane catoptron 66, imaging lens system 67 and ccd sensor 68.In addition, this interferometer has laser driver 71,72,73 as driving control system, platform drive unit 74, and scanning mirror circuit 75, the computing machine 77 of their action is controlled on image processing apparatus 76 and the ground of being all together.

Light supply apparatus 62 has 3 semiconductor laser 62a, 62b, 62c, 2 beam splitter 62e, 62f.Can be made as for example 780nm, 655nm and 405nm from the inspection light wavelength of these semiconductor lasers 62a, 62b, the outgoing of 62c institute; In the case, can instrumentation to various CD with laser, DVD with laser and BD with the corrugated aberration of the object lens 50 of laser etc.

The built-in BPF. of beam splitter 62e; Make inspection light transmission from the 1st semiconductor laser 62a; And make inspection light reflection from the 2nd semiconductor laser 72b, will import same light path from the different inspection light of the wavelength of two halves conductor laser 62a, 62b thus.In addition; Beam splitter 62f built-in BPF.; Make inspection light transmission through beam splitter 62e; And make inspection light reflection from the 3rd semiconductor laser 62c, will import same light path from the different inspection light of the wavelength of all- semiconductor laser instrument 62a, 62b, 62c thus.

Collimator lens 63 makes the light of respectively checking that penetrates from light supply apparatus 62 become parallel beam.In addition, in the case, since bigger from the inspection light wavelength difference of each semiconductor laser 62a, 62b, 62c, so use achromat or collimator lens 63 be replaced with corresponding lens by each wavelength as collimator lens 63.

Beam splitter 64 is transparent panels of parallel flat shape, for example on light beam divisional plane 64a, forms the semi-permeable mirror film.The part that beam splitter 64 will incide its inspection light is made as with reference to light after light beam divisional plane 64a reflects, and is made as seized light after making remaining inspection light transmission.

Checked object can drive by means of not shown man-operated mechanism or platform drive unit 74 with platform 65, and the object lens 50 as checked object is moved to remain in correct position three-dimensionally.In addition; Carry out under the situation of instrumentation for object lens 50 and to its imaging characteristic as illustrating at checked object; Reflect seized light in the configuration of the rear of object lens 50 with reference to concave mirror 81 through object lens 50; After object lens 50 becomes the almost parallel light beam, turn back to beam splitter 64 once more, it is interfered with reference to light.In addition, object lens 50b is designed to carry out optically focused via the parallel plane substrate of regulation, so between with reference to concave mirror 81 and object lens 50, dispose cover plate 82.

Reference plane catoptron 66 is fixed on the holding device 92 via piezoelectric element 91.Piezoelectric element 91 is as the phase place feed mechanism, can stretch according to the control voltage from scanning mirror circuit 75, and makes with reference to catoptron and on the direction of optical axis OAI, critically move back and forth with wavelength level.

Imaging lens system 67 will through beam splitter 64 synthetic, from the seized light of object lens 50 with carry out optically focused with reference to light as synthetic light from reference plane catoptron 66.

In addition, in case projected on the ccd sensor 68 as interference fringe by the synthetic light behind imaging lens system 67 optically focused.The pattern of this interference fringe is outputed to image processing apparatus 76 as electric signal.This electric signal conduct is outputed to computing machine 77 with the corresponding picture signal of interference figure that is projected to ccd sensor 68.

Computing machine 77 can move on optical axis direction through making control scanning mirror circuit 75, reference plane catoptron 66, controls moving of the interference fringe that projected to ccd sensor 68, and can carry out the position control of interference fringe.In addition, computing machine 77 can be to analyzing with the corrugated aberration of instrumentation from the seized light of object lens 50 with the mobile of ccd sensor 68 detected interference fringes.

Below, describe with regard to the action of interference measuring device shown in Figure 27.At first, will be placed on checked object as the object lens 50 of checked object with on the platform 65.Secondly, for example make 71 actions of the 1st laser driver so that CD with laser as checking that light is from the 1st semiconductor laser 62a outgoing.Then, control signal is outputed to scanning mirror circuit 75 so that piezoelectric element 91 changes from computing machine 77.Thus, can make reference plane catoptron 66 carry out the scanning that phase place is sent to, just can carry out high-precision corrugated instrumentation with wavelength for CD.Then, make the action of the 2nd laser driver 72 so that DVD with laser as checking that light is from the 2nd semiconductor laser 62b outgoing.Below same, through reference plane catoptron 66 is carried out scanning that phase place sends to come instrumentation because of object lens 50 that cause with DVD with the relevant corrugated variation of wavelength.Then, make the action of the 3rd laser driver 73 so that BD with laser as checking that light is from the 3rd semiconductor laser 62c outgoing.Below same, through reference plane catoptron 66 is carried out scanning that phase place sends to come instrumentation because of object lens 50 that cause with BD with the relevant corrugated variation of wavelength.

By means of interference measuring device discussed above, just can to object lens 50 with CD with wavelength, DVD with wavelength and BD with the relevant corrugated aberration of wavelength, be that optical characteristics is measured.At this moment; Owing to be the state that makes diffraction lens 2 and tilt with small angle with respect to the optical axis of the object lens body 1 that constitutes object lens 50, so can prevent to incide ccd sensor 68 through beam splitter 64 or imaging lens system 67 from the back light of diffraction lens 2.That is, since result from the noise of back light be difficult to get into ccd sensor 68 scoop up the interference figure of shadow, so can make the corrugated instrumentation high precision int of object lens 50.

In addition; In the object lens as this embodiment 50; Moving diffraction lens 2 under the situation of 3 μ m along the optical axis vertical direction; That is, the optical axis OA1 of diffraction lens 2, OA2 with under the parallel situation of carrying out skew of 3 μ m, are that benchmark make it 5m λ RMS degree or coma aberration it more than take place with the wavelength X with respect to optical axis OA0.In order to suppress such coma aberration as far as possible, not only need make diffraction lens 2 to be aligned in high precision int below several microns but also to need to result from diffraction lens 2 be the pitch angle of optical axis OA1, OA2 and the 1st 2a taking place and the coma aberration of the 2nd 2b reduce simultaneously.Particularly, hope to be suppressed to the coma aberration of 5～50m λ RMS.In this embodiment, optical axis OA1, the OA2 of two sides 2a, 2b is made as optical axis independently, just can the coma aberration of the 1st 2a and the 2nd 2b all be minimized through their interval adjustment result.Its result just can suppress the generation of coma aberration effectively, and can make the object lens 50 that satisfies desired specification expeditiously on the imaging characteristic of object lens 50.

(the 11st embodiment)

Below, describe with regard to the object lens of the 11st embodiment.The object lens of the 11st embodiment is out of shape the object lens 50 of the 10th embodiment shown in Figure 21, and is then common with the 10th embodiment as for the part that does not describe especially.

Figure 28 is the cross-sectional side view of the object lens 150 relevant with the 11st embodiment.Under the situation of this object lens 150, a pair of close optical axis OA1 that connects, the OA2 that are arranged at diffraction lens 102 also have non-vanishing small skew with respect to the optical axis OA0 of object lens body 1.But such inclination is not to result from the shape of picture frame 103 to produce, but result from diffraction lens 102 self flange shape took place.Like this; If the 1st 102a and the 2nd 102b of diffraction lens 102 tilt; Then the relevant optically focused of laser for the wavelength 405nm that uses with BD can not bring special influence; But the relevant optically focused of laser of the wavelength 655nm that uses for the wavelength 780nm that uses with CD and DVD is then given and influence, and aberration might take place when optically focused.Such aberration; The situation of implementing shape etc. with the 1st shown in Figure 26 waits is identical; Be able to offset through the aligning that utilizes mark M1, M2; How the generation that can prevent back light no matter diffraction lens 102 tilts with respect to the optical axis OA0 of object lens body 1 still can realize certain above imaging precision.

(the 12nd embodiment)

Figure 29 has diagrammatically represented to pack into the figure of formation of optical Pickup device of object lens shown in Figure 21 50 or object lens 150 shown in Figure 28.

In this optical Pickup device; Laser from each semiconductor laser 261B, 261D, 261C; Utilize object lens 50,150 to be irradiated to CD DB, DD, DC as optical information recording medium; From the reflected light of each CD DB, DD, DC, finally be imported into each photodetector 267B, 267D, 267C via common object lens 50,150.

Here, the laser that the information regeneration of the 1st CD DB uses (for example BD with, wavelength 405nm) takes place in the 1st semiconductor laser 261B, and laser carries out optically focused with object lens 50,150, the suitable luminous point of formation NA0.85 on information recording surface.The laser that the information regeneration of the 2nd CD DD uses (for example DVD with, wavelength 655nm) takes place in the 2nd semiconductor laser 261D, and laser carries out optically focused with object lens 50,150 afterwards, the suitable luminous point of formation NA0.65 on information recording surface.The laser that the information regeneration of the 3rd CD DC uses (for example CD with, wavelength 780nm) takes place in the 3rd semiconductor laser 261C, and laser carries out optically focused with object lens 50,150 afterwards, the suitable luminous point of formation NA0.51 on information recording surface.In addition; The 1st photodetector 267B attendes institute's information recorded with the 1st CD DB and detects as light signal (for example BD with, wavelength 405nm); The 2nd photodetector 267D attendes institute's information recorded with the 2nd CD DD and detects as light signal (for example DVD with, wavelength 655nm), and the 3rd photodetector 267C attendes institute's information recorded with the 3rd CD DC and detects as light signal (for example CD with, wavelength 780nm).

At first, under the situation of regeneration the 1st CD DB, from the 1st semiconductor laser 261B outgoing laser of wavelength 405nm for example, the light beam of institute's outgoing becomes parallel beam through collimator 262B.This light beam, after seeing through polarization beam splitter 263B, 264D, 264C, through object lens 50,150 by optically focused on the information recording surface MB of the 1st CD DB.

On information recording surface MB according to the light beam of information concave point through the ovennodulation back reflection; See through object lens 50,150 etc. once more; Incide polarization beam splitter 263B; Reflect the back at this and give and astigmatism, and be incident on the 1st photodetector 267B, utilize this output signal and obtain to attend the signal that reads of institute's information recorded at the 1st CD DB by cylindrical lens 265B.

In addition, on the 1st photodetector 267B to detecting focus (focusings) because of the caused light quantity of change in shape, the change in location of luminous point changes) detect or follow the tracks of detection.Based on this detection; The two-dimensional adjustment device of on the retainer 271 that keeps object lens 50,150, being assembled 272; Object lens 50,150 is being moved on the optical axis direction so that be imaged on the information recording surface MB of the 1st CD DB from the light beam of the 1st semiconductor laser 261B, object lens 50,150 is moved on the direction perpendicular to optical axis so that be carried out to picture by the track of regulation from the light beam of the 1st semiconductor laser 261B.

Then, under the situation of regeneration the 2nd CD DD, from the 2nd semiconductor laser 261D outgoing laser of wavelength 655nm for example, the light beam of institute's outgoing becomes parallel beam by collimator 262D.This light beam sees through polarization beam splitter 263D, and 264D reflects with polarization beam splitter, afterwards through after the polarization beam splitter 264C, through object lens 50,150 by optically focused on the information recording surface MD of the 2nd CD DD.

On information recording surface MD according to the light beam of information concave point through the ovennodulation back reflection; See through object lens 50,150 etc. once more; Incide polarization beam splitter 263D after reflecting with polarization beam splitter 264D; Here give and astigmatism by cylindrical lens 265D, and incide on the 2nd photodetector 267D, utilize this output signal and obtain attending the signal that reads of institute's information recorded at the 2nd CD DD through reflection back.

In addition; Identical with the situation of the 1st CD DB; On the 2nd photodetector 267D, detect carrying out focus detection or to follow the tracks of and detect changing because of the caused light quantity of change in shape, the change in location of luminous point, the two-dimensional adjustment device of on the retainer that keeps object lens 50,150, being assembled 272 is in order to focus on and track and object lens 50,150 is moved.

Then; Under the situation of regeneration the 3rd CD DC; From the 3rd semiconductor laser 261C outgoing laser of wavelength 780nm for example; The light beam of institute's outgoing becomes parallel beam by collimator 262C, after seeing through polarization beam splitter 263C and being reflected with polarization beam splitter 264C, through object lens 50,150 by optically focused on the information recording surface MC of the 3rd CD DC.

On information recording surface MC according to the light beam of information concave point through the ovennodulation back reflection; See through object lens 50,150 etc. once more; With inciding polarization beam splitter 263C after the polarization beam splitter 264C reflection; Reflect the back at this and give and astigmatism, and be incident on the 3rd photodetector 267C, utilize its output signal and obtain to attend the signal that reads of institute's information recorded at the 3rd CD DC by cylindrical lens 265C.

In addition; With the 1st and the 2nd CD DB; The situation of DD is identical; To detecting because of the caused light quantity of change in shape, the change in location of luminous point changes, carrying out focus detection or to follow the tracks of and detect, the two-dimensional adjustment device of on the retainer that keeps object lens 50,150, being assembled 272 is in order to focus on and track and object lens 50,150 is moved on the 3rd photodetector 267C.

Though describe the present invention in conjunction with above embodiment, the present invention is not limited to above-mentioned embodiment, can also carry out various distortion.For example with regard to the 1st～the 9th example; About comprising mutatis mutandis mark M1, the concavo-convex profile of M2 etc. are not limited to the situation of example in the example in interior shape, then can also consider and be easy to usability and use various shapes as long as can visually observe via instrumentation equipment etc.

In addition; Though in the above-described embodiment; To the object lens of forming by 2 optical elements 50～350,550; 650,750 be illustrated, but under the situation of the object lens of forming by the optical element more than 3, also can be to aim at for example adjacent any 2 optical elements with the same telltale mark of above-mentioned embodiment.In the case, the assembling of object lens also becomes simple and optical property is also improved.

In addition; Though in the above-described embodiment; Object lens body 1 and diffraction lens 2,102,502,602 and picture frame 3 are made as different piece; But can also make object lens body 1 and picture frame 3 integrated and be made as object lens body 1 with cylindrical flange, diffraction lens 2,102,502,602 and picture frame 3 is integrated and be made as the diffraction lens 2,102,502,602 with cylindrical flange, can both eliminate coma aberration through illustrated aligning in Fig. 6, Fig. 7 etc. in either case.

In addition, in the above-mentioned the 7th and the 8th embodiment, the vergence direction (with reference to the otch 303d of Fig. 9) of inclination mark with the diffraction lens 502,602 of definite object lens 550,650 can be set on picture frame 3 grades.

In addition; Though in the above-described embodiment; Just BD is illustrated as the object lens 50,150,250,350,550,650 of the exchange usefulness of object in being included in, but can also the present invention be applicable to certainly and for example replaces BD and the object lens of exchange usefulness in HD is included in as object etc.Describe particularly; Object lens 50,150,250,350 about the 1st～the 5th embodiment; For example can make it be directed against DVD and HD holds interchangeability, and, then for example can make it be directed against CD, DVD and HD and hold interchangeability about the object lens 550,650 of the 7th～the 9th embodiment.

In addition, though in the 10th and the 11st embodiment, only the 1st of diffraction lens 2,102 the 2a, 102a are provided with mutatis mutandis mark M2, also can be only last the setting mutatis mutandis mark M2 of the 2nd 2b, the 102b of diffraction lens 2,102.In the case, as long as diffraction lens 2,102 tilt quantity with respect to object lens body 1 are able to control, then can the 1st 2a, 102a be aimed at optical mode with the 2nd 2b, 102b simultaneously.In addition, can also be at two sides 2a, the 2b of diffraction lens 2,102,102a, 102b is last to be provided with mutatis mutandis mark.In the case, can be to the 1st 2a, 102a and the 2nd 2b, the optical alignment of 102b is visually confirmed.

In addition, though in the above-described embodiment, the 1st 1a of object lens body 1 is provided with mark M1, can also on the 2nd 1b of object lens body 1, mark M1 be set.

In addition; Be not limited to the situation of embodiment example about comprising concavo-convex or profile to mutatis mutandis mark M1, M2 etc. in interior shape, then can also consider and be easy to usability and use various shapes as long as can visually observe via instrumentation equipment etc.

In addition; In the above-described embodiment; Object lens 50,150 to being made up of 2 optical elements is illustrated; But under the situation of the object lens of forming by the optical element more than 3, also can be to aim at for example adjacent any 2 optical elements with the same telltale mark of above-mentioned embodiment.In the case, can also prevent the back light of the phase control element of diffraction lens 2 that kind freely, the assembling of object lens also becomes simple and optical property is also improved.

In addition; Though in the above-described embodiment; Object lens body 1 and diffraction lens 2,102 and picture frame 3,103 are made as different piece; But can also make object lens body 1 and picture frame 3,103 integrated and be made as object lens body 1 with cylindrical flange portion, perhaps that diffraction lens 2,102 and picture frame 3,103 is integrated and be made as the diffraction lens 2,102 with cylindrical flange portion, can both eliminate coma aberration through illustrated aligning in Fig. 5, Fig. 6 etc. in either case.

In addition; Though in the above-described embodiment; Just BD is illustrated as the object lens 50,150 of the exchange usefulness of object in being included in, but can also the present invention be applicable to certainly and for example replaces BD and the object lens of exchange usefulness in HD is included in as object etc.Describe particularly,, make it be directed against BD, DVD and CD and hold interchangeability, but can also make it for example hold interchangeability to CD, DVD and HD about the object lens 50,150 of the 1st and the 2nd embodiment.

In addition; In the record or regeneration of the used optical information recording medium of the present invention; Normally be used to make the focus of light beam to be focused at the focus servo of the signal recording layer of CD;, object lens that at this moment, fears are entertained that makes it to focus and optical information recording medium make optical information recording medium or object lens damage but colliding.Particularly, optical information recording medium in recent years is that BD, HD DVD etc., high capacity, densification constantly make progress, and the distance between object lens and the dielectric surface (WD) also becomes narrow, thereby this collision possibility increases.Therefore; On opposed of the picture frame that relates to lens unit of the present invention and CD, apply the good material of sliding, for example be the overlay of principal ingredient, also can be employed in the structure that has elasticity material A such as silica resin, rubber on the part that optical information recording medium side surface than object lens also is projected into side medium with fluorine family tree fat.Thus, even if WD shortens and make the collision frequency of object lens and optical information recording medium increase, also can prevent that object lens or optical information recording medium or its both sides from damaging by means of this structure.

It is complicated that problem of the present invention just provides a kind of assembly process that can not make, the lens unit that the imaging characteristic corresponding to the object lens of the exchange type of BD is improved simply.

For this reason, according to one of technical scheme of the present invention, utilize mark M1, M2 on the light path that the optical axis OA1 of object lens body 1 direction is extended, to make the center of center and diffraction lens 2 of object lens body 1 consistent.In the case, the pitch angle of the 1st and the 2nd 2a, 2b is 3 °, and the amount of movement of the 1st 2a is 11 μ m.Under this state; Because the relevant coma aberration of the wavelength 655nm that uses with DVD of skew of the 1st 2a of resulting from is+71m λ; The coma aberration of inclination of the 1st 2a of resulting from is+35m λ; The coma aberration of inclination of the 2nd 2b of resulting from is-105m λ, pretends to object lens 50 whole coma aberrations just to be 0m λ.Thereby, no matter how the value of the tiltangle of diffraction lens 2 can both make the coma aberration that takes place as object lens 50 be roughly zero.

It is to be noted that various distortion and modification are obvious to those skilled in the art.Thereby, have only these distortion and revise not exceed scope of the present invention they just should be interpreted as and include therein.

Claims (83)

1. an optical Pickup device is used lens unit, it is characterized in that, comprising:

Object lens are configured in the optical information recording medium side, have the 1st intrinsic optical axis;

Phase control element is configured in light source side, holds the 2nd intrinsic optical axis and has opposed two optical surfaces with respect to above-mentioned object lens; And

Holding components; With respect to above-mentioned object lens above-mentioned phase control element is held in: among the state that above-mentioned the 2nd optical axis tilts with ormal weight with respect to above-mentioned the 1st optical axis and two optical surfaces of above-mentioned phase control element, central point with at least one optical surface of phase structure prolonged the state on the light path in alignment with the center through above-mentioned the 1st optical axis extending

An optical surface of above-mentioned opposed two optical surfaces of above-mentioned phase control element has the 1st phase structure, and another optical surface has the 2nd phase structure.

2. use lens unit according to the described optical Pickup device of claim 1, it is characterized in that:

The interchangeability that above-mentioned phase control element will be used up for making of at least 2 different wavelengths is given and above-mentioned object lens, state in the use at least 2 make use up among when the long side of wavelength, numerical aperture becomes the state more than or equal to 0.6.

3. use lens unit according to the described optical Pickup device of claim 1, it is characterized in that:

Above-mentioned phase control element will be given and above-mentioned object lens for the interchangeability that making of at least 2 different wavelengths used up; State in the use at least 2 make use up among when the long side of wavelength; Make above-mentioned the 2nd optical axis with respect to above-mentioned the 1st optical axis parallel displacement under the situation of 3 μ m, make it to take place the above coma aberration of 5m λ RMS when establishing wavelength for λ.

4. use lens unit according to the described optical Pickup device of claim 3, it is characterized in that:

Above-mentioned phase control element is flat parts, and the middle section around at least one side's of above-mentioned opposed two optical surfaces above-mentioned the 2nd optical axis has phase structure, and the neighboring area around above-mentioned the 2nd optical axis has tabular surface.

5. use lens unit according to the described optical Pickup device of claim 4, it is characterized in that:

State in the use at least 2 make use up among when the long side of wavelength, make this wavelength grow make and use up the above-mentioned middle section that incides above-mentioned phase control element.

6. use lens unit according to the described optical Pickup device of claim 1, it is characterized in that:

On at least one side of the central point of opposed two optical surfaces of at least one side of the central point of above-mentioned opposed two optical surfaces of above-mentioned phase control element and the above-mentioned object lens that above-mentioned the 1st optical axis passes through, be formed with telltale mark.

7. use lens unit according to the described optical Pickup device of claim 5, it is characterized in that:

On at least one side of the central point of opposed two optical surfaces of at least one side of the central point of above-mentioned opposed two optical surfaces of above-mentioned phase control element and the above-mentioned object lens that above-mentioned the 1st optical axis passes through, be formed with telltale mark.

8. use lens unit according to the described optical Pickup device of claim 7, it is characterized in that:

Above-mentioned object lens have above-mentioned telltale mark on the central point of the optical surface of above-mentioned phase control element side.

9. use lens unit according to the described optical Pickup device of claim 7, it is characterized in that:

Above-mentioned phase control element has above-mentioned telltale mark on the central point of the optical surface that forms phase structure among opposed two optical surfaces of above-mentioned phase control element.

10. use lens unit according to the described optical Pickup device of claim 9, it is characterized in that:

The phase structure of above-mentioned phase control element has diffraction structure and optical path difference is given at least one in the structure.

11. use lens unit according to the described optical Pickup device of claim 10, it is characterized in that:

The phase structure of above-mentioned phase control element to above-mentioned at least 2 make use up among the short side of wavelength additional phase error not, side's additional phase error that wavelength is grown.

12. use lens unit according to the described optical Pickup device of claim 1, it is characterized in that:

Being used to making of at least 2 different wavelengths uses up; One side of opposed two optical surfaces of above-mentioned phase control element; Has acting the 1st phase structure of light to the 1st wavelength of using up one of them at least as making of above-mentioned 2 different wavelengths; The opposing party of above-mentioned opposed two optical surfaces has acting the 2nd phase structure of light to the 2nd wavelength of another one among using up as making of above-mentioned at least 2 different wavelengths.

13. use lens unit according to the described optical Pickup device of claim 12, it is characterized in that:

As benchmark, above-mentioned relatively object lens main body is kept by above-mentioned holding components through the involutory state in position above-mentioned phase control element with the side that the influence of the coma aberration that takes place because of off-centre among the above-mentioned the 1st and the 2nd phase structure is bigger.

14. use lens unit according to the described optical Pickup device of claim 13, it is characterized in that:

Above-mentioned object lens have telltale mark on the central point of the optical surface of above-mentioned phase control element side, above-mentioned phase control element has telltale mark on the central point of the bigger side's of influence who is formed with the coma aberration that takes place because of off-centre among the above-mentioned the 1st and the 2nd phase structure optical surface simultaneously.

15. use lens unit according to the described optical Pickup device of claim 1, it is characterized in that:

Above-mentioned holding components with the opposed outside surface of optical information recording medium on, the surface with optical information recording medium side optical surface of more above-mentioned object lens also be projected into above-mentioned optical information recording medium side, with teat that elastic body constituted.

16. use lens unit according to the described optical Pickup device of claim 1, it is characterized in that:

Above-mentioned holding components with the opposed outside surface of optical information recording medium on, being coated with fluorine family tree fat is the coating of principal ingredient.

17. an optical Pickup device is characterized in that:

Possess the lens unit that claim 1 is put down in writing, and read the information of optical information recording medium or writing information in optical information recording medium.

18. an optical Pickup device is characterized in that:

Possess the lens unit that claim 14 is put down in writing, and read the information of optical information recording medium or writing information in optical information recording medium.

19. an optical Pickup device carries out the reading of information of optical information recording medium, perhaps information is characterized in that possessing to the writing of optical information recording medium:

The lens unit that claim 12 is put down in writing;

The light of above-mentioned the 1st wavelength can take place, to be prolonged the 1st light source that the state on the light path is configured by the above-mentioned center in alignment with the said lens unit; And

The light of above-mentioned the 2nd wavelength can take place, and prolongs from the above-mentioned center of said lens unit that the light path dislocation is configured so that the 2nd light source that the coma aberration of the said lens unit that is taken place about above-mentioned the 2nd wavelength reduces.

20., it is characterized in that according to the described optical Pickup device of claim 19:

Above-mentioned the 1st phase structure is bigger because of the influence of the eccentric coma aberration that takes place compared with above-mentioned the 2nd phase structure.

21., it is characterized in that according to the described optical Pickup device of claim 20:

Above-mentioned object lens; On the central point of the optical surface of above-mentioned phase control element side, have telltale mark, above-mentioned phase control element has telltale mark on the central point that is formed with among the above-mentioned the 1st and the 2nd phase structure because of the bigger side's of influence of the eccentric coma aberration that takes place optical surface simultaneously.

22. an optical Pickup device is used lens unit, it is characterized in that, comprising:

Object lens are configured in the optical information recording medium side and have intrinsic primary optical axis;

Phase control element; Constitute and be configured in the 1st optical surface and 2nd optical surface relative with above-mentioned the 1st optical surface that forms the 2nd phase structure that light source side has formation the 1st phase structure, the 1st secondary optical axis of above-mentioned the 1st optical surface and the 2nd secondary optical axis of above-mentioned the 2nd optical surface are parallel to each other and separate predetermined distance; And

Holding components, above-mentioned relatively object lens keep above-mentioned phase control element, so that above-mentioned the 1st secondary optical axis and above-mentioned the 2nd secondary optical axis are with respect to above-mentioned primary optical axis inclination predetermined angular.

23. use lens unit according to the described optical Pickup device of claim 22, it is characterized in that:

The the above-mentioned the 1st and the 2nd secondary optical axis of above-mentioned phase control element is parallel to the plane that comprises the 1st and the 2nd secondary optical axis with respect to the direction that above-mentioned primary optical axis tilts.

24. use lens unit according to the described optical Pickup device of claim 22, it is characterized in that:

Above-mentioned holding components is to keep above-mentioned phase control element with the central point of above-mentioned the 1st optical surface and the central point of above-mentioned the 2nd optical surface in alignment with state, the above-mentioned relatively object lens that the center of extending through above-mentioned primary optical axis prolongs on the light path.

25. use lens unit according to the described optical Pickup device of claim 22, it is characterized in that:

On at least one side of the central point of opposed two optical surfaces of at least one side of the central point of the above-mentioned the 1st and the 2nd optical surface of above-mentioned phase control element and the above-mentioned object lens that above-mentioned primary optical axis passes through, be formed with telltale mark.

26. use lens unit according to the described optical Pickup device of claim 25, it is characterized in that:

Above-mentioned object lens have above-mentioned telltale mark on the above-mentioned central point of the optical surface of above-mentioned phase control element side.

27. use lens unit according to the described optical Pickup device of claim 22, it is characterized in that:

Above-mentioned phase control element; To give and above-mentioned object lens for the interchangeability that making of 3 different wavelengths used up; Among making of above-mentioned different wavelengths used up, use when the wavelength by at least one side among 2 wavelength of above-mentioned phase control element additive phase, the numerical aperture of the system-wide optical information recording medium side of lens unit becomes the state more than or equal to 0.6.

28. use lens unit according to the described optical Pickup device of claim 22, it is characterized in that:

Above-mentioned phase control element; To give and above-mentioned object lens for the interchangeability that making of 3 wavelength used up;, making of above-mentioned different wavelengths use among using up when the wavelength by at least one side in 2 wavelength of above-mentioned phase control element additive phase; At least one side who makes the above-mentioned the 1st and the 2nd secondary optical axis with respect to above-mentioned primary optical axis parallel displacement under the situation of 3 μ m, make it to take place the above coma aberration of 5m λ RMS when establishing wavelength for λ.

29. use lens unit according to the described optical Pickup device of claim 22, it is characterized in that:

Above-mentioned phase control element is as the above-mentioned the 1st and the 2nd phase structure, has diffraction structure and optical path difference and gives among the structure at least one.

30. use lens unit according to the described optical Pickup device of claim 22, it is characterized in that:

Above-mentioned phase control element will be given and above-mentioned object lens for the interchangeability that making of 3 different wavelengths used up; The making of the 1st wavelength that wavelength is lacked most among simultaneously making of above-mentioned 3 different wavelengths being used up used up not additional phase error, and making of the 2nd and the 3rd wavelength also longer than above-mentioned the 1st wavelength among making of above-mentioned 3 different wavelengths used up used the light additional phase error.

31. use lens unit according to the described optical Pickup device of claim 30, it is characterized in that:

Above-mentioned object lens are used up for making of above-mentioned the 1st wavelength and are made spherical aberration correction carry out optimization.

32. use lens unit according to the described optical Pickup device of claim 22, it is characterized in that:

Above-mentioned phase control element has the mark that is used for the direction that the specific the above-mentioned the 1st and the 2nd secondary optical axis tilts with respect to above-mentioned primary optical axis.

33. use lens unit according to the described optical Pickup device of claim 22, it is characterized in that:

Above-mentioned holding components with the opposed outside surface of optical information recording medium on, the surface with optical information recording medium side optical surface of more above-mentioned object lens also be projected into above-mentioned optical information recording medium side, with teat that elastic body constituted.

34. use lens unit according to the described optical Pickup device of claim 22, it is characterized in that:

Above-mentioned holding components with the opposed outside surface of optical information recording medium on, being coated with fluorine family tree fat is the coating of principal ingredient.

35. an optical Pickup device is used lens unit, it is characterized in that, comprising:

Object lens make emergent light from light source be focused on the information recording surface of optical information recording medium, have an intrinsic primary optical axis;

Phase control element is to be configured in light source side, to have the optical element of opposed two optical surfaces with respect to above-mentioned object lens, on side's optical surface, has the 1st phase structure, on the opposing party, has the 2nd phase structure; And

Holding components, above-mentioned relatively object lens keep above-mentioned phase control element,

Above-mentioned phase control element is held in alignment with state, the above-mentioned relatively object lens main body that the center of extending through above-mentioned primary optical axis prolongs on the light path with the central point of the optical surface that will be formed with above-mentioned the 1st phase structure and the central point of the optical surface that is formed with above-mentioned the 2nd phase structure when to be above-mentioned opposed two optical surfaces with respect to above-mentioned primary optical axis tilt.

36. use lens unit according to the described optical Pickup device of claim 35, it is characterized in that:

Read the information of optical information recording medium or writing information in optical information recording medium.

37. use lens unit according to the described optical Pickup device of claim 35, it is characterized in that:

Above-mentioned holding components with the opposed outside surface of optical information recording medium on, the surface with optical information recording medium side optical surface of more above-mentioned object lens also is projected into teat above-mentioned optical information recording medium side, that constitute with elastic body.

38. use lens unit according to the described optical Pickup device of claim 35, it is characterized in that:

Above-mentioned holding components with the opposed outside surface of optical information recording medium on, being coated with fluorine family tree fat is the coating of principal ingredient.

39. an optical Pickup device is used lens unit, it is characterized in that, comprising:

Object lens converge on the information recording surface of optical information recording medium the emergent light from light source;

Phase control element is the optical element that is configured in light source side with respect to above-mentioned object lens, has the optical surface that has formed phase structure; And

Holding components keeps above-mentioned phase control element,

Above-mentioned phase control element, the intersection point that intersects with respect to the optical axis of the inclined light shaft predetermined angular of above-mentioned object lens and above-mentioned phase control element and the optical surface with above-mentioned phase structure with the optical axis of above-mentioned phase control element prolong the corresponding to state of light path for the center at the optical axis through above-mentioned object lens and are able to keep.

40. use lens unit according to the described optical Pickup device of claim 39, it is characterized in that:

Above-mentioned holding components, integrated and form with a certain side in above-mentioned phase control element and the above-mentioned object lens.

41. use lens unit according to the described optical Pickup device of claim 39, it is characterized in that:

Above-mentioned phase control element comprises opposed two optical surfaces, has only formed phase structure on a certain side's in light source side and object lens side the optical surface.

42. use lens unit according to the described optical Pickup device of claim 39, it is characterized in that:

Above-mentioned phase control element comprises opposed two optical surfaces, has formed the 2nd phase structure having formed on the 1st optical surface of light source side on the 1st phase structure and the 2nd optical surface in above-mentioned object lens side.

43. use lens unit according to the described optical Pickup device of claim 42, it is characterized in that:

Above-mentioned holding components; The 2nd intersection point that the 1st intersection point that intersects with the optical axis and above-mentioned the 1st optical surface of above-mentioned the 1st optical surface of above-mentioned phase control element and the optical axis of above-mentioned the 2nd optical surface and above-mentioned the 2nd optical surface intersect keeps for the center corresponding to state of prolongation light path of the optical axis through above-mentioned object lens.

44. use lens unit according to the described optical Pickup device of claim 39, it is characterized in that:

Be used to have the emergent light of at least 2 different wavelengths light; Above-mentioned phase control element; State in the use at least 2 make use up among when the long side of wavelength; Under the situation of optical axis that makes optical axis with respect to above-mentioned object lens with 3 μ m parallel displacements, make it to take place the above coma aberration of 5m λ RMS, wherein λ is a wavelength.

45. use lens unit according to the described optical Pickup device of claim 39, it is characterized in that:

Above-mentioned phase control element is the flat-shaped part with opposed two optical surfaces; Above-mentioned phase structure forms on the middle section of at least one face among above-mentioned two optical surfaces, and more above-mentioned middle section constitutes with tabular surface in the neighboring area in the radial direction outside.

46. use lens unit according to the described optical Pickup device of claim 39, it is characterized in that:

On the intersection point of the optical axis of the optical surface of above-mentioned the 1st intersection point of above-mentioned phase control element and above-mentioned object lens and above-mentioned object lens, has telltale mark.

47. use lens unit according to the described optical Pickup device of claim 39, it is characterized in that:

Be used to have the emergent light of at least 2 different wavelengths light, above-mentioned phase control element to above-mentioned at least 2 make use up among the short side of wavelength additional phase error not, wavelength is grown side's additional phase error.

48. use lens unit according to the described optical Pickup device of claim 39, it is characterized in that:

In above-mentioned phase control element, above-mentioned object lens and the above-mentioned holding components at least one has the mark of expression for the vergence direction of the optical axis of above-mentioned object lens.

49. use lens unit according to the described optical Pickup device of claim 39, it is characterized in that:

Being used to making of at least 2 different wavelengths uses up; One side of opposed two optical surfaces of above-mentioned phase control element; Be formed with acting the 1st phase structure of the 1st wavelength light to one of using up as making of above-mentioned at least 2 different wavelengths, the opposing party is formed with another acting the 2nd phase structure of the 2nd wavelength light among using up that makes as above-mentioned 2 different wavelengths at least.

50. an optical Pickup device is characterized in that, comprising:

The lens unit that claim 49 is put down in writing;

Above-mentioned the 1st wavelength light can take place, and the above-mentioned center that is configured in the said lens unit prolongs the 1st light source on the light path; And

Above-mentioned the 2nd wavelength light can take place, and prolongs from the above-mentioned center of said lens unit that the light path dislocation is configured so that the 2nd light source that the coma aberration of the said lens unit that is taken place about above-mentioned the 2nd wavelength light reduces,

Carry out optical information recording medium the reading of information, or information is write optical information recording medium.

51., it is characterized in that according to the described optical Pickup device of claim 50:

Optical surface with above-mentioned the 1st phase structure is because of the eccentric coma aberration amount that takes place, the coma aberration amount that takes place greater than the off-centre because of optical surface with above-mentioned the 2nd phase structure.

52., it is characterized in that according to the described optical Pickup device of claim 51:

Telltale mark with point that the optical surface of phase control element side of optical axis and the above-mentioned object lens of the above-mentioned object lens of expression intersects, above-mentioned phase control element is formed with telltale mark on the point of the optical axis intersection of the bigger side's of the influence of the coma aberration that takes place because of off-centre among each optical surface that forms the above-mentioned the 1st and the 2nd phase structure optical surface and above-mentioned phase control element.

53. an optical Pickup device is used lens unit, it is characterized in that, comprising:

Make emergent light from light source be focused at the object lens on the information recording surface of optical information recording medium;

Above-mentioned relatively object lens are configured in light source side and comprise opposed two optical surfaces, are forming the phase control element that forms the 2nd phase structure on the 1st phase structure and the 2nd optical surface in above-mentioned object lens side on the 1st optical surface of light source side among above-mentioned opposed two optical surfaces; And

The holding components that keeps above-mentioned phase control element,

Above-mentioned holding components is with respect to the inclined light shaft predetermined angular of above-mentioned object lens and make among the above-mentioned the 1st and the 2nd optical surface, keeping above-mentioned phase control element for the center consistent state of prolongation light path of the optical axis extending through above-mentioned object lens because of the intersection point of the bigger side's of influence of the eccentric coma aberration that takes place optical surface and optical axis intersection.

54. use lens unit according to the described optical Pickup device of claim 53, it is characterized in that:

A certain side in above-mentioned holding components and above-mentioned phase control element and the above-mentioned object lens is integrated and form.

55. use lens unit according to the described optical Pickup device of claim 53, it is characterized in that:

This lens unit is used to making of at least 2 different wavelengths and uses up; One of optical surface of above-mentioned phase control element; Be formed with acting the 1st phase structure of the 1st wavelength light to one of using up as making of above-mentioned at least 2 different wavelengths, another is formed with another acting the 2nd phase structure of the 2nd wavelength light among using up that makes as above-mentioned 2 different wavelengths at least.

56. use lens unit according to the described optical Pickup device of claim 53, it is characterized in that:

Above-mentioned object lens have telltale mark on the central point of the optical surface of above-mentioned phase control element side, above-mentioned phase control element has telltale mark on the central point of the bigger side's of the influence that is formed with the coma aberration that takes place because of off-centre among the above-mentioned the 1st and the 2nd phase structure optical surface.

57. use lens unit according to the described optical Pickup device of claim 53, it is characterized in that:

In above-mentioned phase control element, above-mentioned object lens and the above-mentioned holding components at least one has the mark of expression with respect to the vergence direction of the optical axis of above-mentioned object lens.

58. an optical Pickup device is characterized in that:

Have the lens unit that claim 53 is put down in writing, and read the information of optical information recording medium or information is write optical information recording medium.

59. an optical Pickup device is used lens unit, it is characterized in that, comprising:

Make emergent light from light source be focused at the object lens on the information recording surface of optical information recording medium;

Above-mentioned relatively object lens are configured in light source side, comprise opposed two optical surfaces, are forming the phase control element that forms the 2nd phase structure on the 1st phase structure and the 2nd optical surface in above-mentioned object lens side on the 1st optical surface of light source side among above-mentioned opposed two optical surfaces; And

The holding components that keeps above-mentioned phase control element,

Above-mentioned holding components, to prolong the light path dislocation from the center of the optical axis extending through above-mentioned object lens respectively with respect to the 2nd intersection point of the 1st intersection point of the inclined light shaft predetermined angular of above-mentioned object lens and above-mentioned the 1st optical surface and its optical axis and above-mentioned the 2nd optical surface and its optical axis so that because of the above-mentioned the 1st and the coma aberration that takes place respectively of the off-centre of the 2nd optical surface roughly the state of equilibrium keeping above-mentioned phase control element.

60. use lens unit according to the described optical Pickup device of claim 59, it is characterized in that:

A certain side in above-mentioned holding components and above-mentioned phase control element and the above-mentioned object lens is integrated and form.

61. use lens unit according to the described optical Pickup device of claim 59, it is characterized in that:

This lens unit is used to making of at least 2 different wavelengths and uses up; One side of opposed two optical surfaces of above-mentioned phase control element; Have acting the 1st phase structure of the 1st wavelength light to one of using up as making of above-mentioned at least 2 different wavelengths, the opposing party has another acting the 2nd phase structure of the 2nd wavelength light in using up that makes as above-mentioned 2 different wavelengths at least.

62. use lens unit according to the described optical Pickup device of claim 59, it is characterized in that:

Above-mentioned object lens with the intersection point of the optical axis of the optical surface of above-mentioned phase control element side on form telltale mark, above-mentioned phase control element has telltale mark respectively on the above-mentioned the 1st and the 2nd intersection point.

63. use lens unit according to the described optical Pickup device of claim 59, it is characterized in that:

Above-mentioned phase control element has at least one mark with respect to the vergence direction of the optical axis of above-mentioned object lens of above-mentioned object lens of expression and above-mentioned holding components.

64. an optical Pickup device is characterized in that, has the lens unit that claim 59 is put down in writing, and reads the information of optical information recording medium or information is write optical information recording medium.

65. an optical Pickup device is used lens unit, it is characterized in that, comprising:

Make emergent light from light source be focused at the object lens on the information recording surface of optical information recording medium;

Above-mentioned relatively object lens are configured in light source side, comprise opposed two optical surfaces, are forming the phase control element that forms the 2nd phase structure on the 1st phase structure and the 2nd optical surface in above-mentioned object lens side on the 1st optical surface of light source side among above-mentioned opposed two optical surfaces; And

The holding components that keeps above-mentioned phase control element,

Above-mentioned phase control element constitutes each optical axis that makes the above-mentioned the 1st and the 2nd optical surface and is parallel to each other and separates predetermined distance, and above-mentioned holding components is keeping above-mentioned phase control element with each optical axis of the above-mentioned the 1st and the 2nd optical surface with respect to the state of the inclined light shaft predetermined angular of above-mentioned object lens.

66. an optical Pickup device is used optical element, it is characterized in that, comprising:

The 1st optical surface with the 1st phase structure; And

Be arranged on and opposed the 2nd optical surface of going up, having the 2nd phase structure of above-mentioned the 1st optical surface,

Wherein, the optical axis of the optical axis of above-mentioned the 1st optical surface and above-mentioned the 2nd optical surface is parallel to each other and separates formation with predetermined distance.

67. optical Pickup device; Be used to from the emergent light of light source to the 1st optical information recording medium with protective substrate thickness t 1 and have protective substrate thickness t 2 the 2nd optical information recording medium each information recording surface recorded information and/or from each information recording surface regenerating information; T1≤t2 wherein; This optical Pickup device is characterised in that, comprising:

Outgoing has the 1st light source of the 1st laser of wavelength X 1;

Outgoing has the 2nd light source of the 2nd laser of wavelength X 2, and wherein λ 1＜λ 2;

Make the object lens of the above-mentioned the 1st and the 2nd laser difference optically focused at the 1st and the 2nd optical information recording medium; And

Above-mentioned relatively object lens are configured in light source side, possess the phase control element of the optical surface with phase structure,

Above-mentioned phase control element, the intersection point that intersects with respect to the inclined light shaft predetermined angular of above-mentioned object lens and optical axis that makes above-mentioned phase control element and the optical surface with above-mentioned phase structure with the optical axis of above-mentioned phase control element prolong the consistent state of light path for the center of the optical axis through above-mentioned object lens and are able to maintenance.

68., it is characterized in that according to the described optical Pickup device of claim 67:

Have above-mentioned object lens and above-mentioned phase control element and be able to the lens unit that keeps by means of holding components.

69., it is characterized in that according to the described optical Pickup device of claim 67:

To the information recording surface recorded information of the 3rd optical information recording medium and/or from the information recording surface regenerating information with the 3rd protective substrate thickness t 3; T2＜t3 wherein; This optical Pickup device also comprises; Outgoing is by the 3rd light source of used the 3rd laser with wavelength X 3 of above-mentioned the 3rd optical information recording medium, and wherein λ 2＜λ 3.

70. optical Pickup device; To the 1st optical information recording medium with protective substrate thickness t 1, have the 2nd optical information recording medium of protective substrate thickness t 2 and have protective substrate thickness t 3 the 3rd optical information recording medium each information recording surface recorded information and/or from each information recording surface regenerating information; T1≤t2 wherein; T2≤t3, this optical Pickup device is characterised in that, comprising:

Outgoing has the 1st light source of the 1st laser of wavelength X 1;

Outgoing has the 2nd light source of the 2nd laser of wavelength X 2, and wherein λ 1＜λ 2;

Outgoing has the 3rd light source of the 3rd laser of wavelength X 3, and wherein λ 2＜λ 3;

Make the object lens of above-mentioned the 1st, the 2nd and the 3rd laser difference optically focused at the 1st, the 2nd and the 3rd optical information recording medium; And

Above-mentioned relatively object lens are configured in light source side, comprise opposed two optical surfaces; Forming the phase control element that forms the 2nd phase structure on the 1st phase structure and the 2nd optical surface on the 1st optical surface of light source side among above-mentioned opposed two optical surfaces in above-mentioned object lens side

The 2nd intersection point that above-mentioned phase control element, the 1st intersection point that intersects with respect to the inclined light shaft predetermined angular of above-mentioned object lens and above-mentioned the 1st optical axis and above-mentioned the 1st optical surface with the 2nd optical axis of the 1st optical axis of above-mentioned the 1st optical surface and above-mentioned the 2nd optical surface and above-mentioned the 2nd optical axis and above-mentioned the 2nd optical surface intersect prolongs the consistent state of light path for the center of the optical axis through above-mentioned object lens respectively and is able to maintenance.

71., it is characterized in that according to the described optical Pickup device of claim 70:

Above-mentioned object lens and above-mentioned phase control element are to be able to the lens unit that keeps by means of holding components.

72., it is characterized in that according to the described optical Pickup device of claim 69:

To the information recording surface recorded information of the 3rd optical information recording medium and/or from the information recording surface regenerating information with the 3rd protective substrate thickness t 3; T2＜t3 wherein; This optical Pickup device also comprises; Outgoing is by the 3rd light source of used the 3rd laser with wavelength X 3 of above-mentioned the 3rd optical information recording medium, and wherein λ 2＜λ 3.

73. optical Pickup device; To the 1st optical information recording medium with protective substrate thickness t 1, have the 2nd optical information recording medium of protective substrate thickness t 2 and have protective substrate thickness t 3 the 3rd optical information recording medium each information recording surface recorded information and/or from each information recording surface regenerating information; T1≤t2 wherein; T2≤t3, this optical Pickup device is characterised in that, comprising:

Outgoing has the 1st light source of the 1st laser of wavelength X 1;

Outgoing has the 2nd light source of the 2nd laser of wavelength X 2, and wherein λ 1＜λ 2;

Outgoing has the 3rd light source of the 3rd laser of wavelength X 3, and wherein λ 2＜λ 3;

Make the object lens of above-mentioned the 1st, the 2nd and the 3rd laser difference optically focused at the 1st, the 2nd and the 3rd optical information recording medium; And

Above-mentioned relatively object lens are configured in light source side, comprise opposed two optical surfaces; Forming the phase control element that forms the 2nd phase structure on the 1st phase structure and the 2nd optical surface on the 1st optical surface of light source side among above-mentioned opposed two optical surfaces in above-mentioned object lens side

Above-mentioned object lens and above-mentioned phase control element are with respect to the inclined light shaft predetermined angular of above-mentioned object lens and make among the above-mentioned the 1st and the 2nd optical surface, be able to maintenance because of the intersection point of the bigger side's of the influence of the coma aberration that off-centre was taken place optical surface and optical axis intersection prolongs the consistent state of light path for the center of the optical axis extending through above-mentioned object lens.

74., it is characterized in that according to the described optical Pickup device of claim 73:

Above-mentioned object lens and above-mentioned phase control element are to be able to the lens unit that keeps by means of holding components.

75. optical Pickup device; To the 1st optical information recording medium with protective substrate thickness t 1, have the 2nd optical information recording medium of protective substrate thickness t 2 and have protective substrate thickness t 3 the 3rd optical information recording medium each information recording surface recorded information and/or from each information recording surface regenerating information; T1≤t2 wherein; T2≤t3, this optical Pickup device is characterised in that, comprising:

Outgoing has the 1st light source of the 1st laser of wavelength X 1;

Outgoing has the 2nd light source of the 2nd laser of wavelength X 2, and wherein λ 1＜λ 2;

Outgoing has the 3rd light source of the 3rd laser of wavelength X 3, and wherein λ 2＜λ 3;

Make the object lens of above-mentioned the 1st, the 2nd and the 3rd laser difference optically focused at the 1st, the 2nd and the 3rd optical information recording medium; And

Above-mentioned relatively object lens are configured in light source side, comprise opposed two optical surfaces; Forming the phase control element that forms the 2nd phase structure on the 1st phase structure and the 2nd optical surface on the 1st optical surface of light source side among above-mentioned opposed two optical surfaces in above-mentioned object lens side

Above-mentioned phase control element and above-mentioned object lens; With inclined light shaft predetermined angular with respect to above-mentioned object lens, and the 2nd intersection point of the 1st intersection point of above-mentioned the 1st optical surface and its optical axis and above-mentioned the 2nd optical surface and its optical axis prolong the light path dislocation from the center of the optical axis extending through above-mentioned object lens respectively so that because of the above-mentioned the 1st and the roughly balanced state of coma aberration that takes place respectively of the off-centre of the 2nd optical surface be able to maintenance.

76., it is characterized in that according to the described optical Pickup device of claim 75:

Above-mentioned object lens and above-mentioned phase control element are to be able to the lens unit that keeps by means of holding components.

77. optical Pickup device; To the 1st optical information recording medium with protective substrate thickness t 1, have the 2nd optical information recording medium of protective substrate thickness t 2 and have protective substrate thickness t 3 the 3rd optical information recording medium each information recording surface recorded information and/or from each information recording surface regenerating information; T1≤t2 wherein; T2≤t3, this optical Pickup device is characterised in that, comprising:

Outgoing has the 1st light source of the 1st laser of wavelength X 1;

Outgoing has the 2nd light source of the 2nd laser of wavelength X 2, and wherein λ 1＜λ 2;

Outgoing has the 3rd light source of the 3rd laser of wavelength X 3, and wherein λ 2＜λ 3;

Make the object lens of above-mentioned the 1st, the 2nd and the 3rd laser difference optically focused at the 1st, the 2nd and the 3rd optical information recording medium; And

Above-mentioned relatively object lens are configured in light source side, comprise opposed two optical surfaces; Forming the phase control element that forms the 2nd phase structure on the 1st phase structure and the 2nd optical surface on the 1st optical surface of light source side among above-mentioned opposed two optical surfaces in above-mentioned object lens side

Above-mentioned phase control element is parallel to each other each optical axis of the above-mentioned the 1st and the 2nd optical surface and separates formation with predetermined distance, is able to keep with respect to the state of the inclined light shaft predetermined angular of above-mentioned object lens with each optical axis of the above-mentioned the 1st and the 2nd optical surface simultaneously.

78., it is characterized in that according to the described optical Pickup device of claim 77:

Above-mentioned object lens and above-mentioned phase control element are to be able to the lens unit that keeps by means of holding components.

79. an optical Pickup device is with the assembly method of lens unit; This optical Pickup device has holding components with lens unit; Make emergent light from light source be focused at object lens on the information recording surface of optical information recording medium and phase control element with the optical surface that forms phase structure; This assembly method is characterised in that: comprise

The 1st step of above-mentioned object lens is installed at above-mentioned holding components;

Above-mentioned phase control element is installed on above-mentioned holding components so that the optical axis of optical surface with above-mentioned phase structure with respect to the 2nd step of the inclined light shaft of above-mentioned object lens;

The phase control element of being installed on the above-mentioned holding components and above-mentioned object lens are carried out the position adjustment, so that the intersection point that the optical axis of the optical surface of the formation phase structure of above-mentioned phase control element and the optical surface with above-mentioned phase structure intersect is for the 3rd consistent step of center prolongation light path of the optical axis extending through above-mentioned object lens;

The 4th step that above-mentioned phase control element is fixed above-mentioned holding components; And

The 5th step that the above-mentioned relatively holding components of above-mentioned object lens is fixed.

80., it is characterized in that according to the described assembly method of claim 79:

Above-mentioned phase control element; To give and above-mentioned object lens for the interchangeability that making of at least 2 different wavelengths used up; One side of opposed two optical surfaces; Have acting the 1st phase structure of light to the 1st wavelength of one of using up as making of above-mentioned at least 2 different wavelengths, the opposing party has another acting the 2nd phase structure of the 2nd wavelength light in using up that makes as above-mentioned 2 different wavelengths at least.

81., it is characterized in that according to the described assembly method of claim 80:

Above-mentioned the 3rd step is to carry out position adjustment so that the 1st optical surface of above-mentioned the 1st phase structure of the formation of above-mentioned phase control element and forming among the 2nd optical surface of the 2nd phase structure because of the optical axis of the bigger side's of the influence of the eccentric coma aberration that takes place optical surface and the crossing intersection point of this optical surface is configured on the center prolongation light path of the optical axis extending through above-mentioned object lens.

82. an optical Pickup device is with the assembly method of lens unit; This optical Pickup device has holding components with lens unit; Make emergent light from light source be focused at the object lens on the information recording surface of optical information recording medium and have the 1st optical surface that forms the 1st phase structure and have the phase control element of the 2nd optical surface of the 2nd phase structure; This assembly method is characterised in that: comprise

The 1st step of above-mentioned object lens is installed at above-mentioned holding components;

Above-mentioned phase control element is installed, so that its 2nd step that tilts with respect to the direction vertical with the optical axis of above-mentioned object lens on above-mentioned holding components;

Above-mentioned phase control element of installing is carried out position adjustment, so that the state that the 2nd intersection point of the 1st intersection point that will above-mentioned the 1st optical surface and its optical axis and above-mentioned the 2nd optical surface and its optical axis is configured to misplace from the center prolongation light path of the optical axis extending through above-mentioned object lens is so that because of the above-mentioned the 1st and the coma aberration that takes place respectively of the off-centre of the 2nd optical surface the 3rd step of equilibrium roughly;

The 4th step that above-mentioned phase control element is fixed above-mentioned holding components; And

The 5th step that the above-mentioned relatively holding components of above-mentioned object lens is fixed.

83., it is characterized in that according to the described assembly method of claim 82:

Above-mentioned phase control element; To give and above-mentioned object lens for the interchangeability that making of at least 2 different wavelengths used up; Optical surface with above-mentioned the 1st phase structure works to the light of the 1st wavelength one of used up as making of above-mentioned at least 2 different wavelengths, and the optical surface with above-mentioned the 2nd phase structure works to another the 2nd wavelength light in using up that makes as above-mentioned 2 different wavelengths at least.

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