JP3336829B2 - Compound objective lens - Google Patents
Compound objective lensInfo
- Publication number
- JP3336829B2 JP3336829B2 JP27040695A JP27040695A JP3336829B2 JP 3336829 B2 JP3336829 B2 JP 3336829B2 JP 27040695 A JP27040695 A JP 27040695A JP 27040695 A JP27040695 A JP 27040695A JP 3336829 B2 JP3336829 B2 JP 3336829B2
- Authority
- JP
- Japan
- Prior art keywords
- lens
- objective lens
- optical
- actuator
- lens elements
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
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- Lenses (AREA)
- Moving Of The Head For Recording And Reproducing By Optical Means (AREA)
- Optical Recording Or Reproduction (AREA)
- Optical Head (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明はＣＤ（コンパクトデ
ィスク）や次世代高密度光ディスク等、透明基板厚みの
異なる２種類以上の異種光記憶媒体を同一装置で再生ま
たは記録可能とする光ピックアップ装置または光記憶装
置に関する。特にこのような光記憶装置に最適な対物レ
ンズの形状に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup device capable of reproducing or recording two or more different types of optical storage media having different transparent substrate thicknesses, such as a CD (compact disk) and a next-generation high-density optical disk. The present invention relates to an optical storage device. In particular, the present invention relates to an optimum shape of an objective lens for such an optical storage device.
【０００２】[0002]
【従来の技術】従来この種の光記憶媒体は、ＣＤ規格
（いわゆるレッドブック）に代表される如く透明基板厚
みが１．２ｍｍの１種類しか存在しなかった。ところが
近年、光記憶媒体の大容量化に向けた技術開発が急速に
進行するなかで、透明基板厚みを０．６ｍｍ程度まで薄
くする規格（ＳＤ−ＢＯＯＫ、Ａｐｒｉｌ−１９９５等
を参照）が有力視されている。これは光記憶媒体の製造
バラツキによるティルト（面振れによる傾き）に起因し
て発生する光学的収差が、透明基板厚みが少ないほど低
減するためであり、高密度化に必要な極小の結像スポッ
トを安定して結像できるようにして、最終的に再生信号
のジッターマージンを確保しようとするものである。2. Description of the Related Art Conventionally, there is only one type of optical storage medium of this type having a transparent substrate thickness of 1.2 mm as represented by the CD standard (so-called Red Book). However, in recent years, while technology development for increasing the capacity of an optical storage medium is progressing rapidly, a standard for reducing the thickness of a transparent substrate to about 0.6 mm (see SD-BOOK, April-1995, etc.) is promising. Have been. This is because the optical aberration generated due to the tilt (tilt due to surface runout) due to the manufacturing variation of the optical storage medium is reduced as the thickness of the transparent substrate is reduced. Is intended to stably form an image, and finally, a jitter margin of a reproduced signal is to be ensured.
【０００３】上述のように透明基板厚みが異なる２種類
以上の光記憶媒体が共存する時代に入り、これら異種記
憶媒体に対して１台で兼用して記録再生できるような光
記憶装置が強く要望されている。この目的のために、図
５，図６に示すように２種類の透明基板厚みのそれぞれ
に最適に光学設計された２種類の個別の独立した対物レ
ンズ２６０，２７０をアクチュエータ２１０の可動部２
１１に搭載し、所望の光記憶媒体に適した対物レンズを
選択する方法が従来から提案されている。ところがこの
ように２種類の個別の独立した対物レンズを搭載する従
来形式の光ピックアップ装置２９０には以下に述べるよ
うな問題点があった。In the era when two or more types of optical storage media having different transparent substrate thicknesses coexist as described above, there is a strong demand for an optical storage device capable of recording and reproducing data on and from these different types of storage media. Have been. For this purpose, as shown in FIGS. 5 and 6, two individual independent objective lenses 260 and 270 which are optimally optically designed for each of the two types of transparent substrate thicknesses are connected to the movable part 2 of the actuator 210.
Conventionally, there has been proposed a method of selecting an objective lens suitable for a desired optical storage medium mounted on the optical disk. However, the conventional type optical pickup device 290 equipped with two types of independent objective lenses has the following problems.
【０００４】＜レンズ移動距離の問題＞図５で個々の対
物レンズ２６０，２７０は従来からある成形法（射出成
形など）で造られるが、必要な瞳径ｄ（通常３ｍｍ程
度）に対して外径Ｄが２倍以上（約６．５ｍｍ）必要と
されている。これはレンズ面２６１，２７１に傷が付か
ないよう保護し、成形歪みを矯正するためのフランジ部
２６２，２７２が必要となっているからである。従って
個々の対物レンズの光軸２６３，２７３の間隔Ｌ’は、
対物レンズ外径間の隙間（最低１ｍｍ）を加味して約８
ｍｍ必要となってしまう。すると光記憶媒体の種類に応
じて対物レンズ２６０，２７０を選択する際に、この距
離Ｌ’（約８ｍｍ）だけ移動するようアクチュエータ２
１０の可動部２１１を大きく回動しなくてはならない。
これはアクチュエータの大型化、対物レンズ選択時間の
増加、消費電流の増加といった問題を引き起こす。<Problem of lens moving distance> In FIG. 5, the individual objective lenses 260 and 270 are formed by a conventional molding method (such as injection molding). The diameter D is required to be twice or more (about 6.5 mm). This is because the lens surfaces 261 and 271 need to be protected from being damaged, and the flange portions 262 and 272 for correcting molding distortion are required. Therefore, the distance L ′ between the optical axes 263 and 273 of each objective lens is
Approximately 8 taking into account the gap between the outer diameters of the objective lens (minimum 1 mm)
mm. Then, when selecting the objective lenses 260 and 270 according to the type of the optical storage medium, the actuator 2 is moved so as to move by this distance L ′ (about 8 mm).
The ten movable parts 211 must be pivoted greatly.
This causes problems such as an increase in the size of the actuator, an increase in the objective lens selection time, and an increase in current consumption.
【０００５】＜レンズ取付け工程の問題＞対物レンズは
樹脂の射出成形で造られることが多いが、射出成形工程
においてゲートから流れ込む流動樹脂の方向に樹脂の結
晶成分が配向する。この配向現象により、成形後の対物
レンズには複屈折が発生して結像スポットの形状に悪影
響を与える。通常はこの複屈折の影響を最小限に抑える
ため、図６でゲート位置２６４，２７４は、入射光束２
３３の偏光面に対して所定角度に来るよう位置設定され
てアクチュエータ２１０の可動部２１１に接着固定され
る。図６に示すような形式の光ピックアップ装置２９０
では２個の対物レンズ２６０，２７０に対して、それぞ
れのゲート位置２６４，２７４を角度設定する必要があ
る。これは人手に頼る工程であり組立工程の複雑化をも
たらすと同時に取付け精度を管理しにくかった。<Problem of lens mounting process> Although an objective lens is often made by injection molding of a resin, a crystal component of the resin is oriented in a direction of a flowing resin flowing from a gate in the injection molding process. Due to this orientation phenomenon, birefringence occurs in the molded objective lens, which has an adverse effect on the shape of the imaged spot. Normally, to minimize the effect of birefringence, the gate positions 264 and 274 in FIG.
The position is set so as to be at a predetermined angle with respect to the polarization plane of 33, and is fixed to the movable section 211 of the actuator 210 by bonding. Optical pickup device 290 of the type shown in FIG.
Then, it is necessary to set the angles of the respective gate positions 264 and 274 with respect to the two objective lenses 260 and 270. This is a process that relies on manual labor, which complicates the assembly process and makes it difficult to control the mounting accuracy.
【０００６】＜コストの問題＞対物レンズには通常１０
０円単位の部品コストがかかっており、光ピックアップ
装置のコストに占める割合も大きい。従って図５，図６
のように対物レンズを複数個搭載する場合には、それだ
け部品コストの上昇を伴ってしまうため、一般市場に広
く普及させるうえでの障害となっていた。<Cost problem> Usually, 10
A component cost of 0 yen unit is required, and a large proportion of the cost of the optical pickup device is large. Therefore, FIGS. 5 and 6
When a plurality of objective lenses are mounted as described above, the cost of parts increases accordingly, which has been an obstacle to widespread use in the general market.
【０００７】[0007]
【発明が解決しようとする課題】本発明は上記課題を解
決するためのものであり、対物レンズ選択時の移動距離
を少なくしてアクチュエータ動作の負担を軽減し、対物
レンズ選択時間の短縮と消費電流の低減を図ること、対
物レンズ取付け工程を簡略化して組立て性を向上するこ
と、異種光記憶媒体に対して記録再生可能な、小型で低
コストな光ピックアップ装置を実現することを主な目的
とする。SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and reduces the moving distance when selecting an objective lens, thereby reducing the load on the operation of the actuator, and shortening and consuming the objective lens selection time. The main objectives are to reduce the current, improve the assemblability by simplifying the mounting process of the objective lens, and realize a small and low-cost optical pickup device capable of recording and reproducing data on and from different types of optical storage media. And
【０００８】[0008]
【課題を解決するための手段】上記課題を解決する本発
明の複合対物レンズは、 １）透明基板厚みの異なる異種光記憶媒体のそれぞれに
略無収差で合焦可能なレンズ素子を複数備え、該レンズ
素子のそれぞれの光軸を平行に揃えて一体の光学部材と
して形成した前記複数のレンズ素子は、それぞれの入射
瞳径ｄが略同一であり、前記複数のレンズ素子は対応す
る光記憶媒体に合焦する際に、一体化された光学部材と
光記憶媒体との作動距離（ＷＤ）が略同一であること、
かつ前記複数のレンズ素子を取り囲むようにフランジ部
が形成され、前記レンズ素子どうしの光軸間隔Ｌは、入
射瞳径ｄの２倍以下に設定されていることを特徴とす
る。According to the present invention, there is provided a compound objective lens comprising: a plurality of lens elements capable of focusing with substantially no aberration on different types of optical storage media having different transparent substrate thicknesses; The plurality of lens elements formed as an integral optical member with their respective optical axes aligned in parallel have substantially the same entrance pupil diameter d, and the plurality of lens elements correspond to the corresponding optical storage medium. The working distance (WD) between the integrated optical member and the optical storage medium is substantially the same when focusing on
In addition, a flange portion is formed so as to surround the plurality of lens elements, and an optical axis interval L between the lens elements is set to be equal to or smaller than twice an entrance pupil diameter d.
【０００９】[0009]
【００１０】[0010]
【００１１】[0011]
【００１２】２）上記１）に関し、樹脂またはガラスで
一体成形され、取付部が非円筒形状であることを特徴と
する。2) Regarding the above item 1), it is characterized in that it is integrally formed of resin or glass, and the mounting portion has a non-cylindrical shape.
【００１３】[0013]
【００１４】[0014]
【作用】本発明の上記構成によれば、 １）従来個別に必要であった対物レンズを複合化できる
ため、小型で低コストな複合対物レンズが得られる。ま
た入射瞳を選択することで異なった仕様の対物レンズと
して機能させることができるうえ、それぞれのレンズ素
子の入射瞳径が略同一であるため、入射瞳を選択して異
なった仕様の対物レンズとして機能させた場合に、検出
光学系に戻る光束径が同等となる。また、入射瞳を選択
して異なった仕様の対物レンズとして機能させた場合で
も、作動距離（ＷＤ）が一定であるため、アクチュエー
タ可動部をフォーカス方向に移動させる必要が無い。更
に、個々のレンズ素子間にはフランジが存在しないた
め、レンズ素子の光軸間隔Ｌは極限まで縮小できる。さ
らに複合対物レンズも軽量化される。更にまた、複合対
物レンズのそれぞれの光軸間隔が短くなり、対物レンズ
選択時のアクチュエータ動作量が少なくなるため、対物
レンズ選択時間が短縮される。また複合対物レンズは軽
量なため、アクチュエータの性能が向上し消費電流が低
減する。さらにはアクチュエータが小型化される。According to the above construction of the present invention: 1) Since the objective lenses that have been individually required conventionally can be combined, a compact and low-cost composite objective lens can be obtained. In addition, by selecting the entrance pupil, it is possible to function as an objective lens with different specifications.Because the entrance pupil diameter of each lens element is almost the same, the entrance pupil is selected and used as an objective lens with different specifications. When functioning, the beam diameter returning to the detection optical system becomes equal. Even when the entrance pupil is selected to function as an objective lens having different specifications, it is not necessary to move the actuator movable section in the focus direction because the working distance (WD) is constant. Further, since there is no flange between the individual lens elements, the distance L between the optical axes of the lens elements can be reduced to the limit. Furthermore, the weight of the compound objective lens is also reduced. Furthermore, the distance between the optical axes of the compound objective lens is shortened, and the amount of operation of the actuator when the objective lens is selected is reduced, so that the objective lens selection time is shortened. Further, since the compound objective lens is lightweight, the performance of the actuator is improved and the current consumption is reduced. Further, the size of the actuator is reduced.
【００１５】[0015]
【００１６】[0016]
【００１７】[0017]
【００１８】２）一体成形であるため成形時の流動方向
が規定され複屈折方向が一義的に決る。また取付け部の
形状が円筒形状でないため取付け時の角度設定も不要と
なる。2) Because of the integral molding, the flow direction during molding is defined, and the birefringence direction is uniquely determined. Further, since the shape of the mounting portion is not cylindrical, it is not necessary to set an angle at the time of mounting.
【００１９】[0019]
【００２０】[0020]
（実施の形態１）実施の形態１は本発明による複合対物
レンズに関するものであり、樹脂の射出成形で造る場合
の実施の形態である。図１は実施の形態１における複合
対物レンズ６０を示す断面図、図２は斜視図である。(Embodiment 1) Embodiment 1 relates to a compound objective lens according to the present invention, and is an embodiment in the case of manufacturing by injection molding of a resin. FIG. 1 is a cross-sectional view showing a compound objective lens 60 according to Embodiment 1, and FIG. 2 is a perspective view.
【００２１】実施の形態１の複合対物レンズ６０は、第
１レンズ６１と第２レンズ６４の二つのレンズ素子を複
合した２焦点対物レンズとして機能する。これらレンズ
素子６１，６４は個別に光学設計されており、図１に示
すように、第１レンズ６１は透明基板厚みＤ１＝０．６
ｍｍの第１光記憶媒体７１の情報記憶層７２に正確に第
１スポット７３を結像するようレンズ面６２，６３を非
球面形状に形成される。一方第２レンズ６４は、透明基
板厚みＤ２＝１．２ｍｍの第２光記憶媒体７４の情報記
憶層７５に正確に第２スポット７６を結像するようレン
ズ面６５，６６を非球面形状に形成される。本実施の形
態の複合、対物レンズ６０はＰＭＭＡ（光学アクリル樹
脂）やＡＰＯ（非晶質ポリオレフィン）等の樹脂で射出
成形して造られる。 ６７は複合対物レンズ６０のレン
ズ面６２，６３，６５，６６の周囲を取囲むように形成
されたフランジであり、これらレンズ面に容易に傷が付
かないよう保護し、さらに射出成形後の残留歪みを矯正
するための補強リブとして機能する。６８は上記のフラ
ンジ６７の一部を成し、アクチュエータ可動部１１の穴
１２（非円形の穴）に挿入される取付部となる。The compound objective lens 60 according to the first embodiment functions as a bifocal objective lens in which two lens elements of a first lens 61 and a second lens 64 are combined. These lens elements 61 and 64 are individually optically designed. As shown in FIG. 1, the first lens 61 has a transparent substrate thickness D1 = 0.6.
The lens surfaces 62 and 63 are formed in an aspherical shape so that an image of the first spot 73 is accurately formed on the information storage layer 72 of the first optical storage medium 71 of mm. On the other hand, the second lens 64 has lens surfaces 65 and 66 formed in an aspherical shape so as to accurately form an image of the second spot 76 on the information storage layer 75 of the second optical storage medium 74 having a transparent substrate thickness D2 = 1.2 mm. Is done. The composite and objective lens 60 of the present embodiment is manufactured by injection molding with a resin such as PMMA (optical acrylic resin) or APO (amorphous polyolefin). Reference numeral 67 denotes a flange formed so as to surround the lens surfaces 62, 63, 65, and 66 of the compound objective lens 60. The flange 67 protects these lens surfaces from being easily damaged, and further has a residue after injection molding. Functions as a reinforcing rib for correcting distortion. Reference numeral 68 forms a part of the flange 67, and serves as a mounting portion to be inserted into the hole 12 (non-circular hole) of the actuator movable portion 11.
【００２２】フランジ６７は図２に示すように第１レン
ズ６１と第２レンズ６４の周囲を取り囲んでいるが、こ
れらのレンズ素子６１，６４の間にはフランジが無い。
従ってレンズ素子６１と６４同士を極限まで接近させる
ことが可能となり、光軸６１ａと光軸６４ａとの距離Ｌ
（光軸間隔）はこの実施の形態の場合約４ｍｍとなる。
これは前述した従来例におけるＬ’＝約８ｍｍに対して
格段に縮小されたことを意味する。ここで、実施の形態
１の第１レンズ６１と第２レンズ６４の設計仕様をまと
めると、次のようになっている。Although the flange 67 surrounds the first lens 61 and the second lens 64 as shown in FIG. 2, there is no flange between these lens elements 61 and 64.
Therefore, the lens elements 61 and 64 can be brought close to each other as much as possible, and the distance L between the optical axis 61a and the optical axis 64a can be reduced.
(Optical axis interval) is about 4 mm in this embodiment.
This means that L '= about 8 mm in the above-described conventional example is significantly reduced. Here, the design specifications of the first lens 61 and the second lens 64 of the first embodiment are summarized as follows.
【００２３】 λ（使用波長）＝６５０ｎｍ ｄ（入射瞳径）＝φ３ｍｍ ＷＤ（作動距離）＝１．６ｍｍ ＮＡ（開口数）＝０．６（第１レンズ） ／ ０．４２（第２レンズ） ｆ（焦点距離）＝２．５ｍｍ（第１レンズ） ／ ３．６ｍｍ（第２レンズ） 媒体の基板厚み＝０．６ｍｍ（第１レンズ） ／ １．２ｍｍ（第２レンズ） 上記のような光学仕様で設計された第１レンズ６１と第
２レンズ６４は、入射瞳径ｄが共通であるという特徴が
ある。これは光ピックアップ装置を構成するうえで非常
に重要であり、レンズ素子６１，６４のどちらを選択し
ても信号検出系に取込まれる受光スポット径が同等にな
るという利点があるため、信号検出の信頼性が確保され
る。また、ＷＤが共通であるのも本発明の特徴的事項の
一つである。これにより、入射瞳を選択して異なった仕
様の対物レンズとして機能させた場合でも、アクチュエ
ータ可動部１１をフォーカス方向に移動させる必要が無
い。Λ (used wavelength) = 650 nm d (entrance pupil diameter) = φ3 mm WD (working distance) = 1.6 mm NA (numerical aperture) = 0.6 (first lens) /0.42 (second lens) f (focal length) = 2.5 mm (first lens) /3.6 mm (second lens) Substrate thickness of medium = 0.6 mm (first lens) /1.2 mm (second lens) Optics as described above The first lens 61 and the second lens 64 designed according to the specification have a feature that the entrance pupil diameter d is common. This is very important in the construction of the optical pickup device. There is an advantage that the diameter of the light receiving spot taken into the signal detection system becomes equal regardless of which of the lens elements 61 and 64 is selected. Reliability is ensured. The fact that the WD is common is also one of the characteristic features of the present invention. Accordingly, even when the entrance pupil is selected and functions as an objective lens having different specifications, it is not necessary to move the actuator movable section 11 in the focus direction.
【００２４】前述のように光軸間隔Ｌは約４ｍｍとして
いるが、一般化して記述すると、 Ｌ≦２×ｄ （ｄは入射瞳径） にするのが良い。これはレンズ素子６１，６４を一体化
したことにより初めて可能となった。Ｌがこの範囲内で
あれば、後述の実施の形態３で示すように対物レンズ選
択時のアクチュエータ可動部を回動が最小限になり、ア
クチュエータ動作の負担が軽減するとともに小型化メリ
ットが生きる。As described above, the optical axis interval L is set to about 4 mm. However, in general terms, it is preferable that L ≦ 2 × d (d is the entrance pupil diameter). This was made possible for the first time by integrating the lens elements 61 and 64. If L is within this range, the rotation of the actuator movable portion when the objective lens is selected is minimized as described in a third embodiment described below, so that the load on the actuator operation is reduced and the advantage of downsizing is realized.
【００２５】図２で複合対物レンズ６０のフランジ６７
にはゲート６９ａが設置され、射出成形時にはこのゲー
ト６９ａから流動樹脂が入り込み金型内に充填される。
金型（非図示）の内部では流動樹脂が一定方向に流れ、
成形後の複合対物レンズ６０には矢印Ｇ方向に樹脂の結
晶成分が配向する。この結晶成分の配向により、複合対
物レンズ６０は若干の複屈折性を有することになる。一
般に、こうした複屈折は対物レンズの焦点スポット形状
に影響するため、入射光束の偏光面と上記配向方向をそ
ろえるようにして、複屈折によるスポット形状の悪化を
最小限に抑える努力がされている。In FIG. 2, the flange 67 of the compound objective lens 60 is shown.
Is provided with a gate 69a, and at the time of injection molding, a fluid resin enters from the gate 69a and is filled in the mold.
Inside the mold (not shown), the flowing resin flows in a certain direction,
In the composite objective lens 60 after molding, the crystal component of the resin is oriented in the direction of arrow G. Due to the orientation of the crystal components, the composite objective lens 60 has some birefringence. In general, since such birefringence affects the focal spot shape of the objective lens, efforts are made to minimize the deterioration of the spot shape due to birefringence by aligning the polarization plane of the incident light beam with the above-described orientation direction.
【００２６】本発明の複合対物レンズ６０は取付部６８
の形状が非円筒形状であるため、アクチュエータ可動部
１１の取付穴１２の形状を取付部６８に合せることで、
自動的に可動部１１と複合対物レンズ６０との角度が規
定される。すなわち、従来のように対物レンズの角度設
定をゲート位置を目視確認しながら調整する方法に対し
て、格段に作業性が向上するとともに角度設定の精度が
向上する。従ってスポット７３，７６は複屈折による形
状悪化を最小限に抑えることができる。The compound objective lens 60 of the present invention has a mounting portion 68.
Is a non-cylindrical shape, so that the shape of the mounting hole 12 of the actuator movable portion 11 matches the mounting portion 68,
The angle between the movable section 11 and the compound objective lens 60 is automatically determined. That is, in contrast to the conventional method of adjusting the angle setting of the objective lens while visually checking the gate position, the workability is remarkably improved and the angle setting accuracy is improved. Therefore, the spots 73 and 76 can minimize shape deterioration due to birefringence.
【００２７】なお、ゲート６９ａに加え反対側にもゲー
ト６９ｂ（図２参照）を追加することも可能であり、射
出成形時の金型内部への樹脂流動速度が速くなるため生
産性が向上する。この場合、複合対物レンズ６０の中央
を横断する位置でウェルド６９ｗ（流動樹脂同士がぶつ
かる境界面）が発生し易くなるが、レンズ素子６１，６
４の間に位置するため光学特性に悪影響を与えずに済
む。このようにゲート数あるいはゲート位置を変更する
ことも本発明の範疇に属する改善内容である。In addition, it is possible to add a gate 69b (see FIG. 2) on the opposite side in addition to the gate 69a, so that the flow rate of the resin into the mold during injection molding is increased, thereby improving the productivity. . In this case, a weld 69w (a boundary surface at which the flowing resins collide) is likely to occur at a position crossing the center of the compound objective lens 60, but the lens elements 61 and 6
4, there is no need to adversely affect the optical characteristics. Changing the number of gates or the gate position in this way is also an improvement that belongs to the category of the present invention.
【００２８】また、以上説明した複合対物レンズ６０は
二つのレンズ素子を有する形式であるが、これを発展さ
せてさらに第３のレンズ素子を形成することも可能であ
る。例えば透明基板厚みが０．６ｍｍ／０．８ｍｍ／
１．２ｍｍと３種類の光記憶媒体のそれぞれに最適設計
された三つのレンズ素子を備えることが可能となる。Further, the compound objective lens 60 described above is of a type having two lens elements, but it is possible to develop this and further form a third lens element. For example, if the thickness of the transparent substrate is 0.6 mm / 0.8 mm /
It is possible to provide three lens elements optimally designed for each of the 1.2 mm and three types of optical storage media.
【００２９】（実施の形態２）実施の形態２は、ガラス
プレス法により複合対物レンズ１６０の成形する実施の
形態であり、図３に複合対物レンズ１６０の斜視図を示
す。複合対物レンズ１６０は第１レンズ１６１と第２レ
ンズ１６４の二つのレンズ素子を複合した２焦点対物レ
ンズとして機能する。(Embodiment 2) Embodiment 2 is an embodiment in which the compound objective lens 160 is formed by a glass pressing method. FIG. 3 is a perspective view of the compound objective lens 160. The compound objective lens 160 functions as a bifocal objective lens in which two lens elements of a first lens 161 and a second lens 164 are combined.
【００３０】図３の複合対物レンズ１６０はガラスプレ
ス法で造られるため、前述の実施の形態１のようなゲー
トは無く複屈折も極めて少ないのが特徴である。また、
ガラスプレス法は金型精度が成形品に正確に転写される
ため、レンズ素子１６１，１６４の面精度は極めて高
い。従って高信頼性が要求される分野にはこのようなガ
ラスプレス法で複合対物レンズ１６０を造るのが望まし
い。Since the compound objective lens 160 shown in FIG. 3 is manufactured by a glass press method, it is characterized in that there is no gate and the birefringence is extremely small as in the first embodiment. Also,
In the glass press method, since the mold accuracy is accurately transferred to the molded product, the surface accuracy of the lens elements 161 and 164 is extremely high. Therefore, in a field where high reliability is required, it is desirable to form the compound objective lens 160 by such a glass press method.
【００３１】この実施の形態２では、レンズ素子１６
１，１６４を取り囲むよう形成されたフランジ部がその
まま取付部１６８として機能する。取付部１６８は図３
に示すように長円形状であり、アクチュエータ可動部
（非図示）に形成された長円穴にはめ込むことで位置設
定される。In the second embodiment, the lens element 16
The flange portion formed so as to surround 1, 164 functions as the mounting portion 168 as it is. The mounting part 168 is shown in FIG.
As shown in the figure, the position is set by fitting into an oval hole formed in an actuator movable portion (not shown).
【００３２】レンズ素子１６１，１６４の光学仕様は前
述の実施の形態１に記載したレンズ素子６１，６４と同
様であり、実施の形態１で説明したような効果を同様に
発揮する。The optical specifications of the lens elements 161 and 164 are the same as those of the lens elements 61 and 64 described in the first embodiment, and the same effects as described in the first embodiment are exhibited.
【００３３】（実施の形態３）実施の形態３は、以上説
明した複合対物レンズを使って所望のレンズ素子を選択
する形式の光ピックアップ９０に関するものである。図
４は前述の実施の形態１で開示した形式の複合対物レン
ズ６０を搭載した光ピックアップ９０を示す斜視図であ
る。(Embodiment 3) Embodiment 3 relates to an optical pickup 90 of a type in which a desired lens element is selected using the compound objective lens described above. FIG. 4 is a perspective view showing an optical pickup 90 equipped with a compound objective lens 60 of the type disclosed in the first embodiment.
【００３４】アクチュエータ１０の可動部１１には複合
対物レンズ６０が搭載され、複合対物レンズ６０は２種
類の透明基板厚みに対応して最適設計された２つのレン
ズ素子６１，６４を機能複合したものである。可動部１
１は回動軸１２を中心に所定角度回動自在に支持され、
第１レンズ６１と第２レンズ６４のいずれかを選択して
光ピックアップ装置９０の光学系９１に組み入れること
ができる。The movable part 11 of the actuator 10 has a composite objective lens 60 mounted thereon. The composite objective lens 60 is a functional composite of two lens elements 61 and 64 optimally designed for two types of transparent substrate thicknesses. It is. Movable part 1
1 is supported so as to be rotatable by a predetermined angle about a rotary shaft 12,
Either the first lens 61 or the second lens 64 can be selected and incorporated into the optical system 91 of the optical pickup device 90.
【００３５】アクチュエータ１０の具体的な機構動作の
詳細は省略するが、第１レンズ６１が光学系９１の光軸
９２に略一致する位置と、第２レンズ６４が光軸９２に
略一致する位置の２点の近傍で、復元力が作用する構造
（いわゆる二安定機構）を採用し、これら二安定位置の
切替えとトラックサーボ用の機構は共通の磁気回路上に
構成されている。またフォーカスサーボ用の磁気回路も
アクチュエータ１０内部に構成されている。Although the details of the specific mechanical operation of the actuator 10 are omitted, the position where the first lens 61 substantially coincides with the optical axis 92 of the optical system 91 and the position where the second lens 64 approximately coincides with the optical axis 92 In the vicinity of the above two points, a structure in which a restoring force acts (a so-called bistable mechanism) is adopted, and the mechanism for switching between the bistable positions and the track servo is configured on a common magnetic circuit. A magnetic circuit for focus servo is also formed inside the actuator 10.
【００３６】次に光ピックアップ９０の動作について、
対物レンズ選択工程を中心に説明する。ここで、光ピッ
クアップ９０は主に新規高密度光ディスクすなわち透明
基板厚みＤ１が０．６ｍｍと薄い媒体を再生する機会が
多いとして、これに対応した第１レンズ６１が光学系の
光軸上に来るよう初期設定される。Next, the operation of the optical pickup 90 will be described.
The description will focus on the objective lens selection step. Here, it is assumed that the optical pickup 90 mainly plays a new high-density optical disc, that is, a medium having a thin transparent substrate thickness D1 of 0.6 mm, and the first lens 61 corresponding to this is located on the optical axis of the optical system. Is initialized as follows:
【００３７】次に光記憶装置側の動作を立上げ、光ピッ
クアップの光学系９１から生成される再生信号等を確認
して、透明基板厚みの識別を行う。この透明基板厚みの
識別方法については詳細な説明を省くが、本出願人によ
る先願の明細書に開示されている方法が使える。ここで
光記憶媒体の透明基板厚みがＤ２（＝１．２ｍｍ）であ
ると識別された場合には、アクチュエータ可動部１１を
図４の矢印Ｒ方向に回動させて、第２レンズ６４が光学
系９１に組込まれるように動作（対物レンズ選択工程）
させれば良い。Next, the operation of the optical storage device is started, and a reproduction signal or the like generated from the optical system 91 of the optical pickup is confirmed to determine the thickness of the transparent substrate. Although a detailed description of the method of identifying the thickness of the transparent substrate is omitted, the method disclosed in the specification of the earlier application by the present applicant can be used. If it is determined that the thickness of the transparent substrate of the optical storage medium is D2 (= 1.2 mm), the actuator movable unit 11 is rotated in the direction of arrow R in FIG. Operate to be incorporated in system 91 (objective lens selection step)
You can do it.
【００３８】このように構成された光ピックアップ装置
９０は、前述の実施の形態１で説明した数々の特徴が反
映される。すなわちレンズ素子６１，６４の光軸間隔Ｌ
が非常に短いため、上記の対物レンズ選択に要する時間
は短縮され、消費電流も僅かで済む。また光軸間隔Ｌの
短縮はアクチュエータ９０の小型化にも大いに寄与す
る。なお複合対物レンズ６０の重量も軽いためアクチュ
エータ動作特性を損なうものでは無い。また対物レンズ
選択時にＷＤ（作動距離）が変化しないため、アクチュ
エータ可動部９１をフォーカス方向に移動させる必要が
無く、アクチュエータ動作の負担にならない。さらにレ
ンズ素子６１，６４の入射瞳径ｄが共通であるため、光
学系９１の信号検出特性は変化しない。The optical pickup device 90 configured as described above reflects various features described in the first embodiment. That is, the optical axis interval L between the lens elements 61 and 64
Is very short, the time required for selecting the objective lens is reduced, and the current consumption is small. Also, the reduction of the optical axis interval L greatly contributes to the miniaturization of the actuator 90. In addition, since the weight of the compound objective lens 60 is light, the operation characteristics of the actuator are not impaired. Further, since the WD (working distance) does not change when the objective lens is selected, there is no need to move the actuator movable section 91 in the focus direction, and there is no burden on the operation of the actuator. Further, since the entrance pupil diameter d of the lens elements 61 and 64 is common, the signal detection characteristics of the optical system 91 do not change.
【００３９】なお補足すると、これまで説明してきた実
施の形態では複合対物レンズを構成するレンズ素子に平
行光束を入射させる形式の、いわゆる無限光学系を用い
ていたが、発散光束が入射する形式の有限光学系として
構成させても良い。また、光ピックアップ装置９０は再
生専用または記録形のいずれの方式にも応用可能であ
る。It should be noted that, in the embodiments described above, a so-called infinite optical system of a type in which a parallel light beam is made incident on a lens element constituting a compound objective lens is used, but a type in which a divergent light beam is made incident. It may be configured as a finite optical system. Further, the optical pickup device 90 can be applied to either a read-only or recording type.
【００４０】このようにして、２種類以上の透明基板厚
みのそれぞれに最適設計された複数のレンズ素子を搭載
した光ピックアップ装置９０において、異なった透明基
板厚みに対応したレンズ素子を簡単に選択できる。よっ
て信頼性の高い記録／再生動作が可能となり、１台の光
ピックアップ装置９０で透明基板厚みの異なる各種光記
憶媒体に対して記録／再生可能となるため、光記憶装置
システムの商品価値は格段に向上する。In this manner, in the optical pickup device 90 equipped with a plurality of lens elements optimally designed for two or more transparent substrate thicknesses, lens elements corresponding to different transparent substrate thicknesses can be easily selected. . Therefore, highly reliable recording / reproducing operation is possible, and recording / reproducing can be performed with respect to various optical storage media having different transparent substrate thicknesses by one optical pickup device 90. To improve.
【００４１】[0041]
【発明の効果】以上説明したように本発明によれば、 １）請求項１に対応する本発明により、従来個別に必要
であった対物レンズを複合化できるため、小型で低コス
トな複合対物レンズが得られ、それぞれのレンズ素子の
入射瞳径が略同一であるため、入射瞳を選択して異なっ
た仕様の対物レンズとして機能させた場合に、検出光学
系に戻る光束径が同等となり信号検出の性能が維持され
る。また、入射瞳を選択して異なった仕様の対物レンズ
として機能させた場合でも、アクチュエータ可動部をフ
ォーカス方向に移動させる必要が無いため、アクチュエ
ータ動作の負担が軽減する。特に、複合対物レンズのそ
れぞれの光軸間隔を格段に短くすることができ、対物レ
ンズ選択時のアクチュエータ動作量が少なくなるため、
対物レンズ選択時間が短縮される。また複合対物レンズ
は軽量なため、アクチュエータの性能が向上し消費電流
が低減する。さらにはアクチュエータが小型化される。As described above, according to the present invention, 1) According to the present invention corresponding to the first aspect, since the objective lens which has been individually required conventionally can be compounded, a compact and low-cost compound objective can be obtained. Since a lens is obtained and the entrance pupil diameter of each lens element is substantially the same, when the entrance pupil is selected and functions as an objective lens with different specifications, the beam diameter returning to the detection optical system becomes equal and the signal Detection performance is maintained. Further, even when the entrance pupil is selected and functions as an objective lens having different specifications, it is not necessary to move the actuator movable section in the focus direction, so that the burden on the actuator operation is reduced. In particular, since the distance between the optical axes of the compound objective lens can be significantly reduced, and the amount of actuator operation when the objective lens is selected is reduced,
Objective lens selection time is reduced. Further, since the compound objective lens is lightweight, the performance of the actuator is improved and the current consumption is reduced. Further, the size of the actuator is reduced.
【００４２】[0042]
【００４３】[0043]
【００４４】[0044]
【００４５】２）請求項２に対応する本発明により、取
付け時の角度設定も不要となるため、組立性が大幅に向
上する。2) According to the second aspect of the present invention, it is not necessary to set an angle at the time of attachment, so that the assemblability is greatly improved.
【００４６】[0046]
【００４７】従って透明基板厚みの異なる異種光記憶媒
体にたいして、最適な対物レンズを選択して記録再生で
きる光ピックアップ装置が実現でき、装置コストが抑え
られ、低消費電流化も可能となる。Therefore, it is possible to realize an optical pickup device capable of selecting and recording and reproducing an optimal objective lens with respect to different types of optical storage media having different transparent substrate thicknesses, thereby reducing the device cost and reducing the current consumption.
【図１】 本発明の実施の形態１の複合対物レンズを示
す断面図である。FIG. 1 is a cross-sectional view illustrating a compound objective lens according to a first embodiment of the present invention.
【図２】 本発明の実施の形態１の複合対物レンズを示
す斜視図である。FIG. 2 is a perspective view showing a compound objective lens according to Embodiment 1 of the present invention.
【図３】 本発明の実施の形態２の複合対物レンズを示
す斜視図である。FIG. 3 is a perspective view showing a compound objective lens according to Embodiment 2 of the present invention.
【図４】 本発明の実施の形態３の光ピックアップ装置
を示す斜視図である。FIG. 4 is a perspective view showing an optical pickup device according to a third embodiment of the present invention.
【図５】 従来形式の対物レンズを示す断面図である。FIG. 5 is a sectional view showing a conventional type objective lens.
【図６】 従来形式の光ピックアップ装置を示す斜視図
である。FIG. 6 is a perspective view showing a conventional optical pickup device.
１０，２１０ アクチュエータ １１，２１１ 可動部 ６０，１６０ 複合対物レンズ ６１，１６１ 第１レンズ ６４，１６４ 第２レンズ ６７ フランジ ６８，１６８ 取付部 ７１，７４ 光記憶媒体 ７３，７６ スポット ９０，２９０ 光ピックアップ装置 ９１ 光学系 10, 210 Actuator 11, 211 Moving part 60, 160 Compound objective lens 61, 161 First lens 64, 164 Second lens 67 Flange 68, 168 Mounting part 71, 74 Optical storage medium 73, 76 Spot 90, 290 Optical pickup device 91 Optical system
Claims (2)
れぞれに略無収差で合焦可能なレンズ素子を複数備え、
該レンズ素子のそれぞれの光軸を平行に揃えて一体の光
学部材として形成した前記複数のレンズ素子は、それぞ
れの入射瞳径ｄが略同一であり、かつ前記複数のレンズ
素子を取り囲むようにフランジ部が形成され、前記レン
ズ素子どうしの光軸間隔Ｌは、入射瞳径ｄの２倍以下に
設定されていることを特徴とする複合対物レンズ。A plurality of lens elements capable of focusing with substantially no aberration on each of different kinds of optical storage media having different transparent substrate thicknesses;
The plurality of lens elements formed as an integrated optical member with their respective optical axes aligned in parallel are substantially the same in entrance pupil diameter d, and are flanged so as to surround the plurality of lens elements. A compound objective lens, wherein a portion is formed, and an optical axis interval L between the lens elements is set to be equal to or smaller than twice an entrance pupil diameter d.
が非円筒形状であることを特徴とする請求項１記載の複
合対物レンズ。2. The compound objective lens according to claim 1, wherein the mounting portion is formed integrally with resin or glass, and the mounting portion has a non-cylindrical shape.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27040695A JP3336829B2 (en) | 1995-10-18 | 1995-10-18 | Compound objective lens |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27040695A JP3336829B2 (en) | 1995-10-18 | 1995-10-18 | Compound objective lens |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09115170A JPH09115170A (en) | 1997-05-02 |
| JP3336829B2 true JP3336829B2 (en) | 2002-10-21 |
Family
ID=17485827
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP27040695A Expired - Lifetime JP3336829B2 (en) | 1995-10-18 | 1995-10-18 | Compound objective lens |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3336829B2 (en) |
Families Citing this family (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7102981B2 (en) | 2001-12-05 | 2006-09-05 | Koninklijke Philips Electronics N.V. | Optical scanning device |
| KR20040068176A (en) * | 2001-12-05 | 2004-07-30 | 코닌클리케 필립스 일렉트로닉스 엔.브이. | Optical scanning device |
| JP2007026507A (en) | 2005-07-14 | 2007-02-01 | Matsushita Electric Ind Co Ltd | Optical pickup device |
| JP4525531B2 (en) * | 2005-08-29 | 2010-08-18 | コニカミノルタオプト株式会社 | Objective lens unit and optical pickup device |
| JP4525530B2 (en) * | 2005-08-29 | 2010-08-18 | コニカミノルタオプト株式会社 | Objective lens unit and optical pickup device |
| JP4753769B2 (en) | 2006-04-04 | 2011-08-24 | 三洋電機株式会社 | Objective lens holding device, optical pickup device |
| JP4528751B2 (en) * | 2006-08-30 | 2010-08-18 | 株式会社日立メディアエレクトロニクス | Lens driving device and optical pickup |
| JP2008077721A (en) * | 2006-09-20 | 2008-04-03 | Funai Electric Co Ltd | Objective lens actuator and optical pickup |
| JP2008146748A (en) * | 2006-12-11 | 2008-06-26 | Konica Minolta Opto Inc | Optical element for optical pickup device and optical pickup device |
| US20100067356A1 (en) * | 2006-12-20 | 2010-03-18 | Hideyuki Fujii | Optical element for optical pickup device, optical pickup device and method for assembling optical pickup device |
| JPWO2008093510A1 (en) * | 2007-01-31 | 2010-05-20 | コニカミノルタオプト株式会社 | Optical element, optical pickup device, and optical pickup device assembly method |
| JPWO2008099631A1 (en) * | 2007-02-14 | 2010-05-27 | コニカミノルタオプト株式会社 | Composite optical element, optical pickup device, mold, and method of manufacturing composite optical element |
| JPWO2008111380A1 (en) * | 2007-03-15 | 2010-06-24 | コニカミノルタオプト株式会社 | Optical element for optical pickup device and optical pickup device |
| JPWO2008117640A1 (en) * | 2007-03-27 | 2010-07-15 | コニカミノルタオプト株式会社 | Lens unit for optical pickup device and optical pickup device |
| JPWO2008117587A1 (en) * | 2007-03-28 | 2010-07-15 | コニカミノルタオプト株式会社 | Optical element for optical pickup device and optical pickup device |
| WO2008120594A1 (en) * | 2007-03-29 | 2008-10-09 | Konica Minolta Opto, Inc. | Optical pickup device lens unit and optical pickup device |
| KR101024094B1 (en) * | 2009-05-18 | 2011-03-22 | (주)옵티스 | Optical pickup equipment for blu ray |
-
1995
- 1995-10-18 JP JP27040695A patent/JP3336829B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09115170A (en) | 1997-05-02 |
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