JPH07153103A - Driving device - Google Patents
Driving deviceInfo
- Publication number
- JPH07153103A JPH07153103A JP29695493A JP29695493A JPH07153103A JP H07153103 A JPH07153103 A JP H07153103A JP 29695493 A JP29695493 A JP 29695493A JP 29695493 A JP29695493 A JP 29695493A JP H07153103 A JPH07153103 A JP H07153103A
- Authority
- JP
- Japan
- Prior art keywords
- yoke
- length
- permanent magnet
- tracking
- coil
- 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.)
- Pending
Links
Landscapes
- Optical Recording Or Reproduction (AREA)
- Reciprocating, Oscillating Or Vibrating Motors (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、小型の可動コイル型ア
クチュエータに係わり、例えばＣＤプレーヤのピックア
ップの如き微小な焦点合わせを行う駆動装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small moving coil type actuator, and more particularly to a driving device for fine focusing such as a pickup of a CD player.
【０００２】[0002]
【従来の技術】従来より、ＣＤプレーヤのような光学的
情報信号再生装置においては、光ディスクの表面に情報
読取り用レンズにて収束されたレーザ光を照射すること
により各種情報信号の再生を行っている。この種装置で
は、前記レンズを所定位置に移動させるための手段とし
て、ヨークと永久磁石を含む磁気回路内にレンズを保持
したボビンに駆動コイルを巻回した可動部材を設けた可
動コイル型のアクチュエータ（レンズ駆動装置）が使用
されている。この駆動装置によればレンズを光軸方向に
移動して光ディスクに形成された情報トラックに対し、
光スポットを適正径にて照射させるためのフォーカス制
御と、レンズを光ディスクの適正位置に照射、追跡させ
るためのトラッキング制御とが行われる。図３（ａ）に
その一例であるＣＤピックアップ装置の斜視図、図３
（ｂ）に同平面図を示す。１は、厚さ方向に着磁され、
同極性の磁極が対向するように配置された励磁用永久磁
石、２は永久磁石１により発生した磁界内でレンズ４を
上下方向に駆動するフォーカスコイル、３は前記磁界内
でレンズ４を前後方向に駆動するトラッキングコイル、
５はフォーカスコイル２とトラッキングコイル３に電流
を供給するための給電ワイヤであり、フォーカスコイル
２とトラッキングコイル３の巻回されたレンズ保持部材
７を支持している。６は２次元的に閉ループを形成した
ヨークであり、６ａと６ｂは各々メインヨーク部位とサ
イドヨーク部位である。そしてこの駆動装置において
は、従来より前記の永久磁石として高性能の希土類鉄ホ
ウ素系磁石や希土類コバルト系磁石が多用され、特に前
記ヨークに内接する永久磁石のＹ方向の長さＬ1とし
て、前記ヨークの内側長さＬ2に近いものが多用されて
いた。2. Description of the Related Art Conventionally, in an optical information signal reproducing apparatus such as a CD player, various information signals are reproduced by irradiating the surface of an optical disk with laser light focused by an information reading lens. There is. In this type of device, as a means for moving the lens to a predetermined position, a movable coil type actuator in which a movable member having a drive coil wound around a bobbin holding the lens in a magnetic circuit including a yoke and a permanent magnet is provided. (Lens drive) is used. According to this drive device, the lens is moved in the optical axis direction to the information track formed on the optical disc,
Focus control for irradiating a light spot with an appropriate diameter and tracking control for irradiating and tracking a lens at an appropriate position on an optical disk are performed. FIG. 3 (a) is a perspective view of a CD pickup device as an example, FIG.
The plan view is shown in FIG. 1 is magnetized in the thickness direction,
Exciting permanent magnets arranged so that magnetic poles of the same polarity are opposed to each other, 2 is a focus coil for vertically driving the lens 4 in a magnetic field generated by the permanent magnet 1, and 3 is a front-back direction of the lens 4 in the magnetic field. Tracking coil to drive
Reference numeral 5 is a power supply wire for supplying a current to the focus coil 2 and the tracking coil 3, and supports a lens holding member 7 around which the focus coil 2 and the tracking coil 3 are wound. Reference numeral 6 is a yoke having a two-dimensional closed loop, and 6a and 6b are a main yoke portion and a side yoke portion, respectively. In this drive device, conventionally, high-performance rare earth iron boron-based magnets and rare earth cobalt-based magnets are frequently used as the permanent magnets, and in particular, as the length L 1 in the Y direction of the permanent magnets inscribed in the yoke, The inner length L 2 of the yoke was often used.
【０００３】[0003]
【発明が解決しようとする課題】前述の如く、従来より
前記永久磁石の長さＬ1を前記ヨークの内側長さＬ2に近
ずけることによりフォーカス感度およびトラッキング感
度が高くなると考えられて来た。しかしながら前記永久
磁石の両端部から発生する磁束が空隙部位を介して透磁
率の高いサイドヨーク部位６ｂ側に流れるために、トラ
ッキングに有効な磁場成分が小さくなり、トラッキング
感度がむしろ低化するケースが発生した。As described above, it has been conventionally considered that the focus sensitivity and the tracking sensitivity are increased by bringing the length L 1 of the permanent magnet closer to the inner length L 2 of the yoke. It was However, since the magnetic flux generated from both ends of the permanent magnet flows to the side yoke portion 6b side having a high magnetic permeability through the air gap portion, the magnetic field component effective for tracking becomes small and the tracking sensitivity is rather lowered in some cases. Occurred.
【０００４】本発明は、前記従来技術に存在する問題点
を解消し、トラッキングコイルへの有効磁場成分を向上
させてトラッキング感度を向上することのできる駆動装
置を提供することを目的とする。SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems existing in the prior art and to provide a driving device capable of improving the effective magnetic field component to the tracking coil to improve the tracking sensitivity.
【０００５】[0005]
【課題を解決するための手段】前記目的を達成するため
に、本発明においては２次元的に閉ループを形成したヨ
ークと前記ヨークに内接固着され、同極性の磁極が対向
するように配置された一対の永久磁石を有する固定部材
と、前記固定部材の内側に配設された情報の記録再生に
係わる機能部材を保持する可動部材とを有し、前記可動
部材の外周にフォーカスコイルとトラッキングコイルと
を巻回した駆動装置において、前記ヨークの内側長さに
対する前記永久磁石の長さの比率を０．８２〜０．９９
とすることによりコイル感度を改善するという技術的手
段を採用した。In order to achieve the above object, according to the present invention, a yoke having a two-dimensionally closed loop and the yoke are inscribed and fixed internally, and the magnetic poles of the same polarity are arranged so as to face each other. A fixed member having a pair of permanent magnets, and a movable member disposed inside the fixed member for holding a functional member for recording and reproducing information, and a focus coil and a tracking coil on the outer periphery of the movable member. In the drive device in which and are wound, the ratio of the length of the permanent magnet to the inner length of the yoke is 0.82 to 0.99.
The technical means of improving the coil sensitivity was adopted.
【０００６】本発明においては、前記ヨークの内側長さ
に対する前記永久磁石の長さの比率を０．８５〜０・９
６とすることがコイル感度の改善の点から更に好まし
い。In the present invention, the ratio of the length of the permanent magnet to the inner length of the yoke is 0.85 to 0.9.
A value of 6 is more preferable from the viewpoint of improving the coil sensitivity.
【０００７】[0007]
【作用】前述の構成により、特にトラッキングコイルへ
の有効磁場成分が増加し、駆動装置のトラッキング感度
の向上が可能となる。With the above-mentioned structure, the effective magnetic field component to the tracking coil is increased, and the tracking sensitivity of the driving device can be improved.
【０００８】[0008]
【実施例】図１は本発明の一実施例を示す平面図であ
り、図示以外の構成部材の配置は図３（ａ）、図３
（ｂ）と同様であり、同一部分は同一の参照符号で示
す。図１において、永久磁石１としてＮｄ−Ｆｅ−Ｂ系
の焼結磁石（日立金属（株）製ＨＳ−４０ＡＨ）を使用
し、一対の永久磁石１の同極性の磁極が対向するように
配置した。この永久磁石の寸法は長さＬ1ｍｍ（Ｙ方
向）、高さ３ｍｍ（Ｚ方向）、厚さ１．６ｍｍ（Ｘ方
向）である。ヨーク６として２次元的に閉ループを形成
した鉄系のヨークを使用し、このヨークの内側寸法を１
７．５ｍｍ（Ｌ2）×１４．６ｍｍとした。本実施例に
おいてはヨークの内側長さＬ2１７．５ｍｍに対して永
久磁石の長さＬ1を変化させた場合のトラッキング感度
の測定を行った。図２に永久磁石長さＬ1と相対トラッ
キング感度との関係を示す。また、表１にヨークの内側
長さ（Ｌ2）に対する永久磁石長さ（Ｌ1）の比率（Ｌ1
／Ｌ2）と相対トラッキング感度との関係を示す。図２
および表１から、永久磁石長さＬ1＝１４．３〜１７．
３ｍｍ（ヨーク内側長さＬ2対比０．８２〜０．９９）
において相対トラッキング感度が向上し、特に永久磁石
長さＬ1＝１４．８〜１６．８ｍｍ（ヨーク内側長さＬ2
対比０．８５〜０．９６）にてトラッキング感度が大幅
に向上することがわかる。DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a plan view showing an embodiment of the present invention, and the arrangement of components other than those shown in FIGS.
Similar to (b), the same parts are denoted by the same reference numerals. In FIG. 1, an Nd-Fe-B based sintered magnet (HS-40AH manufactured by Hitachi Metals, Ltd.) was used as the permanent magnet 1, and the permanent magnets 1 were arranged so that the magnetic poles of the same polarity face each other. . The dimensions of this permanent magnet are length L 1 mm (Y direction), height 3 mm (Z direction), and thickness 1.6 mm (X direction). An iron-based yoke having a two-dimensional closed loop is used as the yoke 6, and the inside dimension of this yoke is set to 1
It was 7.5 mm (L 2 ) × 14.6 mm. In this example, the tracking sensitivity was measured when the length L 1 of the permanent magnet was changed with respect to the inner length L 2 of the yoke of 17.5 mm. FIG. 2 shows the relationship between the permanent magnet length L 1 and the relative tracking sensitivity. Table 1 also shows the ratio (L 1 ) of the permanent magnet length (L 1 ) to the inner length (L 2 ) of the yoke.
/ L 2 ) and the relative tracking sensitivity are shown. Figure 2
From Table 1 and Table 1, the permanent magnet length L 1 = 14.3 to 17.
3 mm (compared to the inner length L 2 of the yoke 0.82 to 0.99)
The relative tracking sensitivity is improved, and in particular the permanent magnet length L 1 = 14.8 to 16.8 mm (yoke inner length L 2
It can be seen that the tracking sensitivity is significantly improved at a contrast of 0.85 to 0.96).
【０００９】[0009]
【表１】 [Table 1]
【００１０】なお、本実施例においては永久磁石の形状
が単純ブロック状の場合について記述したが、異形状で
も同等の効果が得られる。In this embodiment, the case where the permanent magnet has a simple block shape has been described, but the same effect can be obtained even if the permanent magnet has a different shape.
【００１１】[0011]
【発明の効果】本発明は以上記述のような構成および作
用であるから、前記駆動装置の磁気回路を構成する永久
磁石長さとヨーク内側長さとの比率を特定の範囲に設定
することによりトラッキング感度を大幅に向上すること
ができる。Since the present invention has the structure and operation as described above, the tracking sensitivity is set by setting the ratio of the length of the permanent magnet and the length of the inner side of the yoke forming the magnetic circuit of the driving device within a specific range. Can be greatly improved.
【図１】本発明の一実施例に係わる磁気回路を示す平面
図である。FIG. 1 is a plan view showing a magnetic circuit according to an embodiment of the present invention.
【図２】永久磁石長さと相対トラッキング感度との関係
を示す図である。FIG. 2 is a diagram showing a relationship between a permanent magnet length and relative tracking sensitivity.
【図３】ＣＤ用ピックアップ装置の一例を示す斜視図
（ａ）、同平面図（ｂ）である。FIG. 3 is a perspective view (a) and a plan view (b) showing an example of a CD pickup device.
１ 励磁用永久磁石 ２ フォーカスコイル ３ トラッキングコイル ４ レンズ ５ 電流供給ワイヤ ６ ヨーク ６ａ メインヨーク部位 ６ｂ サイドヨーク部位 ７ レンズ保持部材 1 Excitation Permanent Magnet 2 Focus Coil 3 Tracking Coil 4 Lens 5 Current Supply Wire 6 Yoke 6a Main Yoke Part 6b Side Yoke Part 7 Lens Holding Member
Claims (2)
前記ヨークに内接固着され、同極性の磁極が対向するよ
うに配置された一対の永久磁石を有する固定部材と、前
記固定部材の内側に配設された情報の記録再生に係わる
機能部材を保持する可動部材とを有し、前記可動部材の
外周にフォーカスコイルとトラッキングコイルとを巻回
した駆動装置において、 前記ヨークの内側長さに対する前記永久磁石の長さの比
率を０．８２〜０．９９としたことを特徴とする駆動装
置。1. A fixed member having a two-dimensionally closed yoke and a pair of permanent magnets that are internally fixed to the yoke and arranged so that magnetic poles of the same polarity face each other, and the inside of the fixed member. A movable member that holds a functional member relating to recording and reproducing of information, which is disposed in the drive member, in which a focus coil and a tracking coil are wound around the outer periphery of the movable member. A drive device characterized in that the ratio of the lengths of the permanent magnets is 0.82 to 0.99.
石の長さの比率を０．８５〜０．９６としたことを特徴
とする請求項１に記載の駆動装置。2. The drive device according to claim 1, wherein the ratio of the length of the permanent magnet to the inner length of the yoke is 0.85 to 0.96.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29695493A JPH07153103A (en) | 1993-11-26 | 1993-11-26 | Driving device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29695493A JPH07153103A (en) | 1993-11-26 | 1993-11-26 | Driving device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07153103A true JPH07153103A (en) | 1995-06-16 |
Family
ID=17840339
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29695493A Pending JPH07153103A (en) | 1993-11-26 | 1993-11-26 | Driving device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07153103A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100344586B1 (en) * | 1998-11-18 | 2002-10-31 | 삼성전자 주식회사 | Pick-up actuator |
| US6941829B1 (en) | 2003-07-30 | 2005-09-13 | Scott J. Long | Leak detector |
-
1993
- 1993-11-26 JP JP29695493A patent/JPH07153103A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100344586B1 (en) * | 1998-11-18 | 2002-10-31 | 삼성전자 주식회사 | Pick-up actuator |
| US6941829B1 (en) | 2003-07-30 | 2005-09-13 | Scott J. Long | Leak detector |
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