JP2005148656A - Lens, optical pickup, and optical disk unit - Google Patents

Lens, optical pickup, and optical disk unit Download PDF

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JP2005148656A
JP2005148656A JP2003389834A JP2003389834A JP2005148656A JP 2005148656 A JP2005148656 A JP 2005148656A JP 2003389834 A JP2003389834 A JP 2003389834A JP 2003389834 A JP2003389834 A JP 2003389834A JP 2005148656 A JP2005148656 A JP 2005148656A
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lens
optical
lens body
optical axis
axis direction
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Hiroyuki Ueda
博之 上田
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Sony Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens for performing effective astigmatism correction by a sufficient non-axial symmetry in compact shape in which a space in a direction of an optical axis is effectively used without expanding a flange part externally. <P>SOLUTION: In a lens for astigmatism correction in which a main body part 100 of a lens and a flange part 110 are formed in one body by a plastic injection molding, the non-axial symmetry of the main body part 100 of the lens is obtained by forming projecting parts 120 which are projected in the direction of the optical axis on the side face of the flange part 110 and by controlling the behavior of the contraction of resin in the molding die in the resin molding by these projecting parts 120. The projecting parts 120 have, for example, structure to be used as a lens protector for protecting the lens and are formed in symmetrical circular-arc shape in both sides across the optical axis of the lens as projecting parts which correct, for example, the astigmatism by 90 degrees in the direction of the circumference of the optical axis. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、各種の光学装置において光の非点収差補正を行なうための非軸対称性を有するレンズと、このレンズを光学系に用いた光ピックアップ及び光ディスク装置に関する。   The present invention relates to a lens having non-axisymmetric property for correcting astigmatism of light in various optical devices, and an optical pickup and optical disk device using this lens in an optical system.

従来より、例えば光ディスク装置の光学系、例えば対物レンズやコリメータレンズ等の光学素子において、レーザ光源から出射されるスポット光等に含まれる非点収差を除去するために、このスポット光を逆に非点収差を発生させる補正用のレンズを透過させることにより、適正なスポット光に変換することが行なわれており、このような非点収差を発生させるレンズは、例えばレンズの光学面自体を非軸対称に加工することにより実現できるものである。
しかしながら、プラスチック製レンズで光学面自体を非軸対称に加工するには、射出成形用の金型の光学面形成領域の形状を高精度に非軸対称形状に加工するには高度な加工技術が必要となり、種々の困難が伴うことになる。例えば、加工対象である金型を回転させながら、レンズの半径方向に加工する際に、１回転に２周期の速度で工具を変位させる必要があるため、特殊な加工機が必要となる。また、仮に特殊な加工機を実現できたとしても、型加工プロセスの問題点として、切削加工で工具を回転させない場合に、工具を変位させる追従性に限界があるため、金型の高速回転が困難となり、相対速度の低下によって面粗度が低下し、良好な光学面が得られないといった問題が生じる。また、切削加工で工具を回転させる場合に、継続加工となり、工具自体の摩耗や破壊が発生しやすく、量産性に欠ける問題がある。
また、研削加工の場合には、切削加工と異なり、金型と工具の相対速度はコントロール可能であるが、工具自体の摩耗を考えると量産性に欠ける問題がある。 Conventionally, in order to remove astigmatism contained in spot light emitted from a laser light source, for example, in an optical element of an optical disk device, for example, an optical element such as an objective lens or a collimator lens, the spot light is reversed. By passing through a correction lens that generates astigmatism, it is converted into an appropriate spot light. A lens that generates such astigmatism is, for example, a non-axial optical surface of the lens. It can be realized by processing symmetrically.
However, in order to process the optical surface itself non-axisymmetrically with a plastic lens, advanced processing technology is required to process the shape of the optical surface forming region of the mold for injection molding into a non-axisymmetric shape with high accuracy. It becomes necessary and comes with various difficulties. For example, when processing in the radial direction of the lens while rotating the mold to be processed, it is necessary to displace the tool at a speed of two cycles per rotation, so a special processing machine is required. Even if a special processing machine can be realized, the problem with the die machining process is that if the tool is not rotated during cutting, there is a limit to the ability to displace the tool. It becomes difficult, and the surface roughness decreases due to a decrease in the relative speed, resulting in a problem that a good optical surface cannot be obtained. Further, when the tool is rotated by cutting, it is a continuous process, and the tool itself is likely to be worn or broken, resulting in a lack of mass productivity.
In the case of grinding, unlike the cutting, the relative speed between the mold and the tool can be controlled. However, considering the wear of the tool itself, there is a problem of lack of mass productivity.

そこで従来は、レンズの光学面自体に非軸対称性を加工する代わりに、レンズの外周に設けられるフランジ部の形状を工夫することにより、成形時における樹脂の挙動を制御し、光学面の非軸対称性を得るようにしたものが提案されている（例えば、特許文献１参照）。
すなわち、この特許文献１（以下、従来例という）においては、フランジ部の対称位置に小径部を形成することにより、非軸対称性を有するレンズを形成し、非点収差を生じるような構成となっている。
特開平１１−９５００６号公報 Therefore, conventionally, instead of processing the non-axisymmetric property on the optical surface of the lens itself, the shape of the flange portion provided on the outer periphery of the lens is devised to control the behavior of the resin at the time of molding, so There has been proposed one that obtains axial symmetry (see, for example, Patent Document 1).
That is, in Patent Document 1 (hereinafter referred to as a conventional example), a lens having a non-axisymmetric property is formed by forming a small diameter portion at a symmetrical position of the flange portion, and astigmatism is generated. It has become.
Japanese Patent Laid-Open No. 11-95006

しかしながら、上述した従来例では、フランジ部の対称位置に小径部を形成するために、フランジ部の外周部が半径方向に凹凸を有するものとなり、十分な非軸対称性を得ようとすると、半径方向に十分広いフランジ部を設け、半径方向の凹凸を大きくする必要があり、レンズの横幅が広くなって、光学径内に配置することが困難になる。
一方、レンズの光軸方向については、焦点距離等の条件に基づいて隣接する光学素子に対して所定の間隔を設ける必要があるため、フランジ部の光軸方向の空間は十分なスペースを有することが一般的であるが、上記従来例のレンズでは、この光軸方向のスペースが行かされていないという課題がある。
そこで本発明は、フランジ部を外側に広げることなく、光軸方向のスペースを有効利用したコンパクトな形状で、十分な非軸対称性による有効な非点収差補正を行なうことができるレンズ、並びに、このレンズを光学系に搭載した光ピックアップ及び光ディスク装置を提供することを目的とする。 However, in the above-described conventional example, in order to form a small diameter portion at the symmetrical position of the flange portion, the outer peripheral portion of the flange portion has irregularities in the radial direction. It is necessary to provide a sufficiently wide flange portion in the direction to increase the unevenness in the radial direction, and the lateral width of the lens becomes wide, making it difficult to dispose within the optical diameter.
On the other hand, with respect to the optical axis direction of the lens, it is necessary to provide a predetermined interval with respect to adjacent optical elements based on conditions such as the focal length, so that the space in the optical axis direction of the flange portion has sufficient space. However, in the conventional lens, there is a problem that the space in the optical axis direction is not left.
Accordingly, the present invention provides a lens capable of performing effective astigmatism correction with sufficient non-axisymmetricity in a compact shape that effectively utilizes the space in the optical axis direction without expanding the flange portion outward, and It is an object of the present invention to provide an optical pickup and an optical disc apparatus in which this lens is mounted in an optical system.

上述の目的を達成するため、本発明のレンズは、光軸方向に対して両側面に光学面を有するレンズ本体部と、前記レンズ本体部の外周に沿って形成されたフランジ部と、前記フランジ部の少なくとも光軸方向の一方の側面に光軸方向に突出して形成された突起部とが樹脂成形によって一体形成され、前記突起部はレンズ本体部の外周に沿って所定の間隔おきに間欠的に複数形成され、前記樹脂成形時に成形型内における樹脂収縮の挙動を制御してレンズ本体部の非軸対称性を得ることを特徴とする。 また、本発明のレンズは、光軸方向に対して両側面に光学面を有するレンズ本体部と、前記レンズ本体部の外周に沿って形成されたフランジ部と、前記フランジ部の少なくとも光軸方向の一方の側面に光軸方向に突出して形成された突起部とが樹脂成形によって一体形成され、前記突起部はレンズ本体部の外周に沿って不均一な断面形状を有する円環状に形成され、前記樹脂成形時に成形型内における樹脂収縮の挙動を制御してレンズ本体部の非軸対称性を得ることを特徴とする。   In order to achieve the above-described object, the lens of the present invention includes a lens body portion having optical surfaces on both sides with respect to the optical axis direction, a flange portion formed along an outer periphery of the lens body portion, and the flange. And at least one side surface in the optical axis direction is integrally formed by resin molding, and the protrusions are intermittently formed at predetermined intervals along the outer periphery of the lens body. And a non-axisymmetric property of the lens body is obtained by controlling the behavior of resin shrinkage in the mold during the resin molding. The lens of the present invention includes a lens body having optical surfaces on both sides with respect to the optical axis direction, a flange formed along the outer periphery of the lens body, and at least the optical axis direction of the flange A protrusion formed on the one side surface of the lens body in an optical axis direction is integrally formed by resin molding, and the protrusion is formed in an annular shape having a non-uniform cross-sectional shape along the outer periphery of the lens body. The non-axisymmetric property of the lens body is obtained by controlling the behavior of resin shrinkage in the mold during the resin molding.

また、本発明の光ピックアップは、光記録媒体にレーザ光を照射し、その戻り光を検出することにより、前記光記録媒体に対する情報の記録または再生を行なう光学系内に光の非点収差補正を行なうレンズを有し、前記レンズは、光軸方向に対して両側面に光学面を有するレンズ本体部と、前記レンズ本体部の外周に沿って形成されたフランジ部と、前記フランジ部の少なくとも光軸方向の一方の側面に光軸方向に突出して形成された突起部とが樹脂成形によって一体形成され、前記突起部はレンズ本体部の外周に沿って所定の間隔おきに間欠的に複数形成され、前記樹脂成形時に成形型内における樹脂収縮の挙動を制御してレンズ本体部の非軸対称性を得ることを特徴とする。
また、本発明の光ピックアップは、光軸方向に対光記録媒体にレーザ光を照射し、その戻り光を検出することにより、前記光記録媒体に対する情報の記録または再生を行なう光学系内に光の非点収差補正を行なうレンズを有し、前記レンズは、光軸方向に対して両側面に光学面を有するレンズ本体部と、前記レンズ本体部の外周に沿って形成されたフランジ部と、前記フランジ部の少なくとも光軸方向の一方の側面に光軸方向に突出して形成された突起部とが樹脂成形によって一体形成され、前記突起部はレンズ本体部の外周に沿って不均一な断面形状を有する円環状に形成され、前記樹脂成形時に成形型内における樹脂収縮の挙動を制御してレンズ本体部の非軸対称性を得ることを特徴とする。 The optical pickup according to the present invention corrects astigmatism of light in an optical system for recording or reproducing information on the optical recording medium by irradiating the optical recording medium with laser light and detecting the return light. The lens includes a lens body portion having optical surfaces on both side surfaces with respect to the optical axis direction, a flange portion formed along an outer periphery of the lens body portion, and at least one of the flange portions. Protrusions that protrude in the optical axis direction are integrally formed on one side surface in the optical axis direction by resin molding, and a plurality of the protrusions are intermittently formed at predetermined intervals along the outer periphery of the lens body. In addition, the non-axisymmetric property of the lens body is obtained by controlling the behavior of the resin shrinkage in the mold during the resin molding.
Further, the optical pickup of the present invention irradiates the optical recording medium with laser light in the direction of the optical axis, and detects the return light, thereby allowing the optical pickup to record or reproduce information on the optical recording medium. A lens body part that has optical surfaces on both sides with respect to the optical axis direction, a flange part formed along the outer periphery of the lens body part, A projection formed to protrude in the optical axis direction on at least one side surface of the flange portion is integrally formed by resin molding, and the projection has a non-uniform cross-sectional shape along the outer periphery of the lens body portion And a non-axisymmetric property of the lens body portion is obtained by controlling the behavior of the resin shrinkage in the mold during the resin molding.

また、本発明の光ディスク装置は、光ディスクにレーザ光を照射し、その戻り光を検出することにより、前記光ディスクに対する情報の記録または再生を行なう光学系内に光の非点収差補正を行なうレンズを有し、前記レンズは、光軸方向に対して両側面に光学面を有するレンズ本体部と、前記レンズ本体部の外周に沿って形成されたフランジ部と、前記フランジ部の少なくとも光軸方向の一方の側面に光軸方向に突出して形成された突起部とが樹脂成形によって一体形成され、前記突起部はレンズ本体部の外周に沿って所定の間隔おきに間欠的に複数形成され、前記樹脂成形時に成形型内における樹脂収縮の挙動を制御してレンズ本体部の非軸対称性を得ることを特徴とする。
また、本発明の光ディスク装置は、光ディスクにレーザ光を照射し、その戻り光を検出することにより、前記光ディスクに対する情報の記録または再生を行なう光学系内に光の非点収差補正を行なうレンズを有し、前記レンズは、光軸方向に対して両側面に光学面を有するレンズ本体部と、前記レンズ本体部の外周に沿って形成されたフランジ部と、前記フランジ部の少なくとも光軸方向の一方の側面に光軸方向に突出して形成された突起部とが樹脂成形によって一体形成され、前記突起部はレンズ本体部の外周に沿って不均一な断面形状を有する円環状に形成され、前記樹脂成形時に成形型内における樹脂収縮の挙動を制御してレンズ本体部の非軸対称性を得ることを特徴とする。 The optical disc apparatus of the present invention includes a lens that corrects astigmatism of light in an optical system that records or reproduces information on the optical disc by irradiating the optical disc with laser light and detecting the return light. The lens includes a lens body portion having optical surfaces on both side surfaces with respect to the optical axis direction, a flange portion formed along an outer periphery of the lens body portion, and at least an optical axis direction of the flange portion. Protrusions formed on one side surface so as to protrude in the optical axis direction are integrally formed by resin molding, and a plurality of the protrusions are intermittently formed at predetermined intervals along the outer periphery of the lens body. It is characterized in that the non-axial symmetry of the lens body is obtained by controlling the behavior of resin shrinkage in the mold during molding.
The optical disc apparatus of the present invention includes a lens that corrects astigmatism of light in an optical system that records or reproduces information on the optical disc by irradiating the optical disc with laser light and detecting the return light. The lens includes a lens body portion having optical surfaces on both side surfaces with respect to the optical axis direction, a flange portion formed along an outer periphery of the lens body portion, and at least an optical axis direction of the flange portion. A protrusion formed on one side surface so as to protrude in the optical axis direction is integrally formed by resin molding, and the protrusion is formed in an annular shape having a non-uniform cross-sectional shape along the outer periphery of the lens body. It is characterized in that the non-axial symmetry of the lens body is obtained by controlling the behavior of resin shrinkage in the mold during resin molding.

本発明にかかるレンズ、光ピックアップ、及び光ディスク装置によれば、光の非点収差補正を行なうレンズのフランジ部に、光軸方向に突出し、レンズ本体部の外周に沿って所定の間隔おきに間欠的に複数形成された突起部、または、レンズ本体部の外周に沿って不均一な断面形状を有する円環状に形成された突起部を設け、この突起部によって、レンズの樹脂成形時に成形型内における樹脂収縮の挙動を制御してレンズ本体部の非軸対称性を得るようにしたことから、フランジ部を外側に広げることなく、光軸方向のスペースを有効利用したコンパクトな形状で、十分な非軸対称性による有効な非点収差補正を行なうことができる。したがって、特殊な加工機や加工方法を用いてレンズの光学面自体を軸非対称形に直接加工することなく、容易に軸非対称性を得ることができ、光学系の各種光学特性の改善等に寄与できる効果がある。   According to the lens, the optical pickup, and the optical disc apparatus according to the present invention, the lens protrudes in the optical axis direction to the flange portion of the lens for correcting the astigmatism of light, and intermittently at predetermined intervals along the outer periphery of the lens body portion. A plurality of protrusions are formed, or a protrusion formed in an annular shape having a non-uniform cross-sectional shape is provided along the outer periphery of the lens main body, and this protrusion allows the inside of the mold to be formed during resin molding of the lens. Since the non-axisymmetric property of the lens body is obtained by controlling the resin shrinkage behavior, the compact shape that effectively utilizes the space in the optical axis direction without expanding the flange part outside is sufficient. Effective astigmatism correction by non-axial symmetry can be performed. Therefore, it is possible to easily obtain axial asymmetry without directly processing the lens optical surface itself into an axially asymmetric shape using a special processing machine or processing method, contributing to improvement of various optical characteristics of the optical system, etc. There is an effect that can be done.

本実施の形態では、プラスチック射出成形によってレンズ本体部とフランジ部とを一体に成形される非点収差補正用のレンズにおいて、フランジ部の側面に光軸方向に突出した突起部を形成し、この突起部によって樹脂成形時に成形型内における樹脂収縮の挙動を制御してレンズ本体部の非軸対称性を得るようにしたものである。
この突起部は、例えばレンズを保護するためのレンズプロテクタを兼用する構造を有し、例えば非点収差を光軸回り方向に９０°補正する突起部として、レンズの光軸を挟んで両側に対称形の円弧状に形成されている。そして、突起部の半径方向の断面積Ｓ、この突起部と隣接するレンズ本体部の光学面部分の断面積ＳＳ、レンズ外径Ｄ（Ｌｅｎｓ）、レンズ本体部の非球面または球面の有効径Ａｐｅ（ａｓｐ）、非球面または球面の中の光学有効径Ａｐｅ（ｏｐｔ）、非球面または球面の有効径Ａｐｅ（ａｓｐ）から突起部の内周縁部までの間隔ｄ１、１つの突起部が形成されている領域の角度α、２つの突起部の間欠領域の角度β、突起部の体積Ｖが下記の式１で表される関係を満たすように形成される。 In the present embodiment, in the lens for correcting astigmatism in which the lens main body portion and the flange portion are integrally molded by plastic injection molding, a protrusion protruding in the optical axis direction is formed on the side surface of the flange portion. The protrusions control the resin shrinkage behavior in the mold during resin molding to obtain the non-axisymmetric property of the lens body.
This protrusion has a structure that also serves as a lens protector for protecting the lens, for example, and is symmetrical on both sides of the optical axis of the lens as a protrusion that corrects astigmatism by 90 ° around the optical axis. It is formed in a circular arc shape. Then, the cross-sectional area S in the radial direction of the protrusion, the cross-sectional area SS of the optical surface portion of the lens main body adjacent to the protrusion, the lens outer diameter D (Lens), the effective diameter Ape of the aspherical surface or spherical surface of the lens main body. (Asp), an effective optical diameter Ape (opt) in the aspherical surface or spherical surface, a distance d1 from the effective diameter Ape (asp) of the aspherical surface or spherical surface to the inner peripheral edge portion of the protruding portion, and one protruding portion is formed. Is formed so that the angle α of the region in which the region is located, the angle β of the intermittent region of the two protrusions, and the volume V of the protrusion satisfy the relationship represented by the following formula 1.

Figure 2005148656
なお、突起部の形状としては、種々変形が可能であり、例えば、レンズ本体部の外周に沿って不均一な断面形状を有する円環状に形成されたものであってもよく、必要とする非点収差補正の特性に応じて適宜採用できるものとする。
Figure 2005148656
 The shape of the protrusion can be variously modified. For example, it may be formed in an annular shape having a non-uniform cross-sectional shape along the outer periphery of the lens main body, and may be required. It can be adopted as appropriate according to the characteristics of the point aberration correction.

図１は本発明の実施例によるレンズの形状を示す斜視図であり、図２は図１のレンズを一部破断して示す斜視図である。
また、図３は図１に示すレンズの寸法条件を示す説明図であり、図４はレンズの寸法条件と非点収差補正効果との相関関係を示す説明図である。
さらに、図５は図１に示すレンズによる非点収差補正光の波面の変化を示す説明図である。 FIG. 1 is a perspective view showing the shape of a lens according to an embodiment of the present invention, and FIG. 2 is a perspective view showing a partially broken lens of FIG.
3 is an explanatory diagram showing the dimensional condition of the lens shown in FIG. 1, and FIG. 4 is an explanatory diagram showing the correlation between the dimensional condition of the lens and the astigmatism correction effect.
Further, FIG. 5 is an explanatory diagram showing changes in the wavefront of the astigmatism correction light by the lens shown in FIG.

図１に示すように、本実施例のレンズは、プラスチックの射出成形加工により、光軸方向に対して両側面に光学面を有するレンズ本体部１００と、このレンズ本体部１００の外周に沿って形成されたフランジ部１１０と、このフランジ部１１０の光軸方向の一方の側面に突出して形成された一対の突起部１２０とが一体形成されたものである。
突起部１２０は、レンズ本体部の外周に沿って所定の間隔おきに間欠的な円弧状に形成され、光軸を挟んで対称形に設けられている。このような突起部１２０を設けることにより、樹脂成形時に成形型内における樹脂収縮の挙動を制御してレンズ本体部の非軸対称性を得るようになっている。すなわち、レンズ本体部１００の光学面において、突起部１２０を設けた部分と、設けていない部分とで、溶融樹脂の流れに差異が生じ、収縮、硬化後の曲面が微妙に変化することになり、非軸対称形状によって非点収差の補正作用を得ることができる。
なお、図１に示す例では、フランジ部１１０の片方の面だけに突起部１２０を設けているが、両面に設けてもよいし、さらに、他のレンズプロテクタが設けられていてもよいものとする。
また、図１の例では、レンズ本体部１００の両側の光学面１００Ａ、１００Ｂが凸レンズである例を示しているが、凹レンズの場合であっても同様に適用し得るものである。 As shown in FIG. 1, the lens according to the present embodiment includes a lens main body 100 having optical surfaces on both side surfaces with respect to the optical axis direction and an outer periphery of the lens main body 100 by plastic injection molding. The formed flange portion 110 and a pair of projecting portions 120 formed so as to protrude from one side surface of the flange portion 110 in the optical axis direction are integrally formed.
The protrusions 120 are formed in an intermittent arc shape at predetermined intervals along the outer periphery of the lens body, and are provided symmetrically across the optical axis. By providing such a protrusion 120, the resin shrinkage behavior in the mold is controlled during resin molding to obtain the non-axisymmetric property of the lens body. That is, on the optical surface of the lens body 100, a difference occurs in the flow of the molten resin between the portion where the protrusion 120 is provided and the portion where the protrusion 120 is not provided, and the curved surface after shrinkage and curing slightly changes. Astigmatism correction action can be obtained by the non-axisymmetric shape.
In the example shown in FIG. 1, the protrusion 120 is provided on only one surface of the flange 110, but it may be provided on both surfaces, and another lens protector may be provided. To do.
In the example of FIG. 1, an example in which the optical surfaces 100A and 100B on both sides of the lens main body 100 are convex lenses is shown, but the present invention can be similarly applied even in the case of a concave lens.

このような突起部の寸法は、例えば図３に示す式１に基づいて決定することが可能である。この場合、例えば図４に示すように、レンズの光学面（球面または非球面）の有効径外周と突起部（レンズプロテクタ）の内周との間の距離ｄ１を小さくすれば、それだけ補正される非点収差量が大きくなる。なお、図４は突起部の大きさを一定とした場合の測定例であり、横軸が距離ｄ１（ｍｍ）、縦軸が非点収差量（λｒｍｓ）を示している。そこで、突起部の大きさや位置を設計することにより、所望とする非点収差補正量を得ることが可能となる。
なお、本例のように光軸に対称形状で一対の突起部を設けた場合には、光軸回りに９０°回転方向の非点収差を発生させる作用を得ることができ、例えば、図５に示すように、９０°回転方向の非点収差を有する入射光２００を本実施例のレンズ２１０を透すことにより、非点収差のない出射光（補正光）２２０を得ることが可能となる。
なお、本例では、一対の突起部によって光軸回りに９０°回転方向の非点収差を発生させる作用を得る場合について説明しているが、例えば４５°回転方向の非点収差を発生させる作用を得る場合には、例えば４つの突起部を設けることで可能となり、突起部の具体的形状については、必要に応じて適宜に採用できるものとする。
また、本実施例では、互いに分離した複数の突起部をフランジ部に設けた例を示しているが、例えば円環状の突起部で、部分的に高さを変えたり、厚みを変えるといった不均一な断面形状を設けることで、本実施例の突起部と同様の作用効果を得ることができるものである。 The dimensions of such a protrusion can be determined based on, for example, Equation 1 shown in FIG. In this case, for example, as shown in FIG. 4, if the distance d1 between the outer periphery of the effective diameter of the optical surface (spherical surface or aspherical surface) of the lens and the inner periphery of the protrusion (lens protector) is reduced, the correction is made accordingly. The amount of astigmatism increases. FIG. 4 shows an example of measurement when the size of the protrusion is constant. The horizontal axis indicates the distance d1 (mm), and the vertical axis indicates the amount of astigmatism (λrms). Therefore, a desired astigmatism correction amount can be obtained by designing the size and position of the protrusion.
In addition, when a pair of protrusions having a symmetrical shape on the optical axis is provided as in this example, an effect of generating astigmatism in a 90 ° rotation direction around the optical axis can be obtained. For example, FIG. As shown in FIG. 5, the incident light 200 having astigmatism in the rotation direction of 90 ° is transmitted through the lens 210 of the present embodiment, so that it is possible to obtain outgoing light (correction light) 220 having no astigmatism. .
In this example, the case of obtaining the action of generating astigmatism in the 90 ° rotation direction around the optical axis by the pair of protrusions has been described. For example, the action of generating astigmatism in the 45 ° rotation direction is described. For example, it is possible to provide four protrusions, and the specific shape of the protrusions can be appropriately adopted as necessary.
Further, in this embodiment, an example in which a plurality of protrusions separated from each other is provided on the flange portion, but for example, an uneven shape such as an annular protrusion that partially changes the height or the thickness is uneven. By providing a simple cross-sectional shape, it is possible to obtain the same effects as the protrusions of the present embodiment.

最後に、上述のような非収差補正用のレンズを設ける光ピックアップ及び光ディスク装置の構成例について説明する。なお、本例のレンズは種々の光学機器に広く応用可能であり、また、光ピックアップ及び光ディスク装置についても多種多様であり、以下に説明する構成が本発明を限定するものでないことはもちろんである。
図６は本実施例の光ディスク装置の構成例を示すブロック図である。
図示のように、この光ディスク装置は、光ディスク３００を回転駆動するスピンドルモータ３１０と、光ディスク３００に対して信号の記録や再生を行なう光ピックアップ３２０と、スピンドルモータ３１０や光ピックアップ３２０の駆動制御を行なうサーボ制御部３３０と、記録信号や再生信号、並びに各種サーボ制御用信号の処理を行なう信号処理部３４０と、本光ディスク装置のシステム全体の制御を行なうシステム制御部３５０とを有する。
このような構成の光ディスク装置において、例えば光ピックアップの対物レンズやコリメータレンズ等で必要となる非点収差補正を上述した図１〜図３に示すレンズを用いて補正することにより、適正な信号の再生や記録を行なうことが可能となる。 Finally, a configuration example of an optical pickup and an optical disc apparatus provided with the above-described non-aberration correction lens will be described. Note that the lens of this example can be widely applied to various optical devices, and there are various types of optical pickups and optical disk devices. Of course, the configuration described below does not limit the present invention. .
FIG. 6 is a block diagram showing a configuration example of the optical disc apparatus of the present embodiment.
As shown in the figure, this optical disc apparatus performs a spindle motor 310 for rotationally driving the optical disc 300, an optical pickup 320 for recording and reproducing signals on the optical disc 300, and drive control of the spindle motor 310 and the optical pickup 320. It has a servo control unit 330, a signal processing unit 340 that processes recording signals and reproduction signals, and various servo control signals, and a system control unit 350 that controls the entire system of the optical disk apparatus.
In the optical disk apparatus having such a configuration, for example, by correcting the astigmatism correction necessary for an objective lens or a collimator lens of an optical pickup using the lens shown in FIGS. Playback and recording can be performed.

本発明の実施例によるレンズの形状を示す斜視図である。It is a perspective view which shows the shape of the lens by the Example of this invention. 図１のレンズを一部破断して示す斜視図である。FIG. 2 is a perspective view showing a partially broken lens of FIG. 1. 図１に示すレンズの寸法条件を示す説明図である。It is explanatory drawing which shows the dimension conditions of the lens shown in FIG. レンズの寸法条件と非点収差補正効果との相関関係を示す説明図である。It is explanatory drawing which shows the correlation with the dimension conditions of a lens, and the astigmatism correction effect. 図１に示すレンズによる非点収差補正光の波面の変化を示す説明図である。It is explanatory drawing which shows the change of the wave front of the astigmatism correction light by the lens shown in FIG. 本発明の実施例の光ディスク装置の構成例を示すブロック図である。It is a block diagram which shows the structural example of the optical disk apparatus of the Example of this invention.

符号の説明Explanation of symbols

１００……レンズ本体部、１１０……フランジ部、１２０……突起部。   100 ... Lens body, 110 ... Flange, 120 ... Protrusion.

Claims (14)

光軸方向に対して両側面に光学面を有するレンズ本体部と、前記レンズ本体部の外周に沿って形成されたフランジ部と、前記フランジ部の少なくとも光軸方向の一方の側面に光軸方向に突出して形成された突起部とが樹脂成形によって一体形成され、
前記突起部はレンズ本体部の外周に沿って所定の間隔おきに間欠的に複数形成され、前記樹脂成形時に成形型内における樹脂収縮の挙動を制御してレンズ本体部の非軸対称性を得る、
ことを特徴とするレンズ。 A lens body having optical surfaces on both sides with respect to the optical axis direction, a flange formed along the outer periphery of the lens body, and an optical axis direction on at least one side surface of the flange in the optical axis direction And a protrusion formed so as to protrude integrally with resin molding,
A plurality of the protrusions are intermittently formed at predetermined intervals along the outer periphery of the lens body, and the non-axisymmetric property of the lens body is obtained by controlling the behavior of resin shrinkage in the mold during the resin molding. ,
A lens characterized by that. 前記突起部はレンズ本体の両側に一対、互いに軸対称形状で設けられていることを特徴とする請求項１記載のレンズ。   The lens according to claim 1, wherein a pair of the projecting portions are provided on both sides of the lens body so as to be axisymmetric with each other. 前記突起部の半径方向の断面積Ｓ、前記突起部と隣接するレンズ本体部の光学面部分の断面積ＳＳ、レンズ外径Ｄ（Ｌｅｎｓ）、レンズ本体部の非球面または球面の有効径Ａｐｅ（ａｓｐ）、前記非球面または球面の中の光学有効径Ａｐｅ（ｏｐｔ）、前記非球面または球面の有効径Ａｐｅ（ａｓｐ）から前記突起部の内周縁部までの間隔ｄ１、１つの突起部が形成されている領域の角度α、２つの突起部の間欠領域の角度β、突起部の体積Ｖが下記の式１で表される関係を満たすことを特徴とする請求項２記載のレンズ。
Figure 2005148656
 The cross-sectional area S in the radial direction of the protrusion, the cross-sectional area SS of the optical surface portion of the lens main body adjacent to the protrusion, the lens outer diameter D (Lens), the effective diameter Ape of the aspherical or spherical surface of the lens main body ( asp), an effective optical diameter Ape (opt) in the aspherical surface or spherical surface, a distance d1 from the effective diameter Ape (asp) of the aspherical surface or spherical surface to the inner peripheral edge portion of the protruding portion, and one protruding portion is formed. 3. The lens according to claim 2, wherein the angle α of the projected region, the angle β of the intermittent region of the two protrusions, and the volume V of the protrusion satisfy the relationship represented by the following formula 1.
Figure 2005148656
 前記突起部はレンズ本体の保護を行なうレンズプロテクタの少なくとも一部を兼用していることを特徴とする請求項１記載のレンズ。   The lens according to claim 1, wherein the protrusion serves as at least a part of a lens protector that protects the lens body. 光軸方向に対して両側面に光学面を有するレンズ本体部と、前記レンズ本体部の外周に沿って形成されたフランジ部と、前記フランジ部の少なくとも光軸方向の一方の側面に光軸方向に突出して形成された突起部とが樹脂成形によって一体形成され、
前記突起部はレンズ本体部の外周に沿って不均一な断面形状を有する円環状に形成され、前記樹脂成形時に成形型内における樹脂収縮の挙動を制御してレンズ本体部の非軸対称性を得る、
ことを特徴とするレンズ。 A lens body having optical surfaces on both sides with respect to the optical axis direction, a flange formed along the outer periphery of the lens body, and an optical axis direction on at least one side surface of the flange in the optical axis direction And a protrusion formed so as to protrude integrally with resin molding,
The protrusion is formed in an annular shape having a non-uniform cross-sectional shape along the outer periphery of the lens body, and the non-axisymmetric property of the lens body is controlled by controlling the behavior of resin shrinkage in the mold during the resin molding. obtain,
A lens characterized by that. 前記突起部はレンズ本体の保護を行なうレンズプロテクタの少なくとも一部を兼用していることを特徴とする請求項１記載のレンズ。   The lens according to claim 1, wherein the protrusion serves as at least a part of a lens protector that protects the lens body. 光記録媒体にレーザ光を照射し、その戻り光を検出することにより、前記光記録媒体に対する情報の記録または再生を行なう光学系内に光の非点収差補正を行なうレンズを有し、
前記レンズは、光軸方向に対して両側面に光学面を有するレンズ本体部と、前記レンズ本体部の外周に沿って形成されたフランジ部と、前記フランジ部の少なくとも光軸方向の一方の側面に光軸方向に突出して形成された突起部とが樹脂成形によって一体形成され、
前記突起部はレンズ本体部の外周に沿って所定の間隔おきに間欠的に複数形成され、前記樹脂成形時に成形型内における樹脂収縮の挙動を制御してレンズ本体部の非軸対称性を得る、
ことを特徴とする光ピックアップ。 A lens for correcting astigmatism of light in an optical system for recording or reproducing information on the optical recording medium by irradiating the optical recording medium with laser light and detecting the return light;
The lens includes a lens body portion having optical surfaces on both side surfaces with respect to the optical axis direction, a flange portion formed along an outer periphery of the lens body portion, and at least one side surface of the flange portion in the optical axis direction. And a protrusion formed so as to protrude in the optical axis direction are integrally formed by resin molding,
A plurality of the protrusions are intermittently formed at predetermined intervals along the outer periphery of the lens body, and the non-axisymmetric property of the lens body is obtained by controlling the behavior of resin shrinkage in the mold during the resin molding. ,
An optical pickup characterized by that. 前記突起部はレンズ本体の保護を行なうレンズプロテクタの少なくとも一部を兼用していることを特徴とする請求項７記載の光ピックアップ。   8. The optical pickup according to claim 7, wherein the protrusion also serves as at least a part of a lens protector that protects the lens body. 光軸方向に対光記録媒体にレーザ光を照射し、その戻り光を検出することにより、前記光記録媒体に対する情報の記録または再生を行なう光学系内に光の非点収差補正を行なうレンズを有し、
前記レンズは、光軸方向に対して両側面に光学面を有するレンズ本体部と、前記レンズ本体部の外周に沿って形成されたフランジ部と、前記フランジ部の少なくとも光軸方向の一方の側面に光軸方向に突出して形成された突起部とが樹脂成形によって一体形成され、
前記突起部はレンズ本体部の外周に沿って不均一な断面形状を有する円環状に形成され、前記樹脂成形時に成形型内における樹脂収縮の挙動を制御してレンズ本体部の非軸対称性を得る、
ことを特徴とする光ピックアップ。 A lens that corrects astigmatism of light in an optical system that records or reproduces information on the optical recording medium by irradiating the optical recording medium with laser light in the optical axis direction and detecting the return light. Have
The lens includes a lens body portion having optical surfaces on both side surfaces with respect to the optical axis direction, a flange portion formed along an outer periphery of the lens body portion, and at least one side surface of the flange portion in the optical axis direction. And a protrusion formed so as to protrude in the optical axis direction are integrally formed by resin molding,
The protrusion is formed in an annular shape having a non-uniform cross-sectional shape along the outer periphery of the lens body, and the non-axisymmetric property of the lens body is controlled by controlling the behavior of resin shrinkage in the mold during the resin molding. obtain,
An optical pickup characterized by that. 前記突起部はレンズ本体の保護を行なうレンズプロテクタの少なくとも一部を兼用していることを特徴とする請求項９記載の光ピックアップ。   The optical pickup according to claim 9, wherein the protrusion also serves as at least a part of a lens protector that protects the lens body. 光ディスクにレーザ光を照射し、その戻り光を検出することにより、前記光ディスクに対する情報の記録または再生を行なう光学系内に光の非点収差補正を行なうレンズを有し、
前記レンズは、光軸方向に対して両側面に光学面を有するレンズ本体部と、前記レンズ本体部の外周に沿って形成されたフランジ部と、前記フランジ部の少なくとも光軸方向の一方の側面に光軸方向に突出して形成された突起部とが樹脂成形によって一体形成され、
前記突起部はレンズ本体部の外周に沿って所定の間隔おきに間欠的に複数形成され、前記樹脂成形時に成形型内における樹脂収縮の挙動を制御してレンズ本体部の非軸対称性を得る、
ことを特徴とする光ディスク装置。 A lens for correcting astigmatism of light in an optical system for recording or reproducing information on the optical disc by irradiating the optical disc with laser light and detecting its return light;
The lens includes a lens body portion having optical surfaces on both side surfaces with respect to the optical axis direction, a flange portion formed along an outer periphery of the lens body portion, and at least one side surface of the flange portion in the optical axis direction. And a protrusion formed so as to protrude in the optical axis direction are integrally formed by resin molding,
A plurality of the protrusions are intermittently formed at predetermined intervals along the outer periphery of the lens body, and the non-axisymmetric property of the lens body is obtained by controlling the behavior of resin shrinkage in the mold during the resin molding. ,
An optical disc device characterized by the above. 前記突起部はレンズ本体の保護を行なうレンズプロテクタの少なくとも一部を兼用していることを特徴とする請求項１１記載の光ディスク装置。   12. The optical disk apparatus according to claim 11, wherein the protrusion also serves as at least a part of a lens protector that protects the lens body. 光ディスクにレーザ光を照射し、その戻り光を検出することにより、前記光ディスクに対する情報の記録または再生を行なう光学系内に光の非点収差補正を行なうレンズを有し、
前記レンズは、光軸方向に対して両側面に光学面を有するレンズ本体部と、前記レンズ本体部の外周に沿って形成されたフランジ部と、前記フランジ部の少なくとも光軸方向の一方の側面に光軸方向に突出して形成された突起部とが樹脂成形によって一体形成され、
前記突起部はレンズ本体部の外周に沿って不均一な断面形状を有する円環状に形成され、前記樹脂成形時に成形型内における樹脂収縮の挙動を制御してレンズ本体部の非軸対称性を得る、
ことを特徴とする光ディスク装置。 A lens for correcting astigmatism of light in an optical system for recording or reproducing information on the optical disc by irradiating the optical disc with laser light and detecting its return light;
The lens includes a lens body portion having optical surfaces on both side surfaces with respect to the optical axis direction, a flange portion formed along an outer periphery of the lens body portion, and at least one side surface of the flange portion in the optical axis direction. And a protrusion formed so as to protrude in the optical axis direction are integrally formed by resin molding,
The protrusion is formed in an annular shape having a non-uniform cross-sectional shape along the outer periphery of the lens body, and the non-axisymmetric property of the lens body is controlled by controlling the behavior of resin shrinkage in the mold during the resin molding. obtain,
An optical disc device characterized by the above. 前記突起部はレンズ本体の保護を行なうレンズプロテクタの少なくとも一部を兼用していることを特徴とする請求項１３記載の光ディスク装置。   14. The optical disk apparatus according to claim 13, wherein the protrusion serves also as at least a part of a lens protector that protects the lens body.
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011159334A (en) * 2010-01-29 2011-08-18 Ricoh Co Ltd Optical element, lens actuator for optical pickup using the same, optical pickup, and optical disk drive
JP2020021064A (en) * 2018-08-04 2020-02-06 エーエーシー テクノロジーズ ピーティーイー リミテッド Optical lens and optical lens unit

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011159334A (en) * 2010-01-29 2011-08-18 Ricoh Co Ltd Optical element, lens actuator for optical pickup using the same, optical pickup, and optical disk drive
JP2020021064A (en) * 2018-08-04 2020-02-06 エーエーシー テクノロジーズ ピーティーイー リミテッド Optical lens and optical lens unit

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