JPH0294123A - Object lens driving device - Google Patents
Object lens driving deviceInfo
- Publication number
- JPH0294123A JPH0294123A JP24804688A JP24804688A JPH0294123A JP H0294123 A JPH0294123 A JP H0294123A JP 24804688 A JP24804688 A JP 24804688A JP 24804688 A JP24804688 A JP 24804688A JP H0294123 A JPH0294123 A JP H0294123A
- Authority
- JP
- Japan
- Prior art keywords
- track
- magnetic gap
- track direction
- magnets
- object lens
- 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
- 230000004907 flux Effects 0.000 claims abstract description 15
- 230000002093 peripheral effect Effects 0.000 abstract 1
- 230000007423 decrease Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
Landscapes
- Optical Recording Or Reproduction (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、光デイスク装置における対物レンズ駆動装置
に関し、特に対物レンズを駆動する磁気回路に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an objective lens driving device in an optical disk device, and more particularly to a magnetic circuit for driving an objective lens.
従来、この種の対物レンズ駆動装置は第４図に示す様に
、対物レンズ１を保持している可動部２が４本のワイヤ
３ａ、３ｂ、３ｃ、３ｄを介して固定部４に支持されて
いる。可動部２にはフォーカス方向駆動用のフォーカス
コイル５とトラック方向駆動様の２対のトラックコイル
６ａ、６ｂ６ｃ、６ｄが形成されている。また、磁気回
路は、１対の磁石７ａ、７ｂとセンターヨーク８ａおよ
びサイドヨーク８ｂならびにヨーク８ａ、８ｂを連絡す
るボトムヨーク（第３図には図示せず）とサイドヨーク
８ｂに固着された磁石７ａ、７ｂとからなる磁気回路が
設けられ、磁石７ａ、７ｂとサイドヨーク８ｂの間に磁
気ギャップ９が形成されている。可動部２はフォーカス
コイル５に駆動電流を流すことによって上下方向に駆動
され、トラックコイル６ａ、６ｂ、６ｃ、６ｄへ駆動電
流を流すことによって左右方向、すなわちトラック方向
（トラックに直交する方向）に駆動される構戒となって
いた。Conventionally, in this type of objective lens driving device, as shown in FIG. 4, a movable part 2 holding an objective lens 1 is supported by a fixed part 4 via four wires 3a, 3b, 3c, and 3d. ing. A focus coil 5 for driving in the focus direction and two pairs of track coils 6a, 6b6c, and 6d for driving in the track direction are formed in the movable part 2. In addition, the magnetic circuit includes a pair of magnets 7a, 7b, a center yoke 8a, a side yoke 8b, a bottom yoke (not shown in FIG. 3) that connects the yokes 8a, 8b, and a magnet fixed to the side yoke 8b. A magnetic circuit consisting of magnets 7a and 7b is provided, and a magnetic gap 9 is formed between the magnets 7a and 7b and the side yoke 8b. The movable part 2 is driven in the vertical direction by passing a drive current through the focus coil 5, and in the left-right direction, that is, in the track direction (direction perpendicular to the track) by passing a drive current through the track coils 6a, 6b, 6c, and 6d. It was a driven stance.
上述した従来の対物レンズ駆動装置は、対物レンズ１を
駆動するための磁気回路を形成している磁気ギャップに
おいて、ヨークが平面で形成されているので、磁気ギャ
ップ中の磁束密度は、磁気ギャップ中心に比べて中心か
らトラック方向へすれると減少する。In the conventional objective lens driving device described above, the yoke is formed in a flat plane in the magnetic gap forming the magnetic circuit for driving the objective lens 1. Therefore, the magnetic flux density in the magnetic gap is centered at the center of the magnetic gap. Compared to , it decreases as it slides away from the center towards the track.
第５図（ａ＞に示す様に、対物レンズ１が静止状態では
１対のトラックコイル６ａ、６ｂは磁気回路のトラック
方向に対しての中心線Ａにおいて、左右対象に置かれて
いるので、トラック方向に発生する力のバランスは平衡
になっている。第５図（ｂ）に示す様に対物レンズ１が
トラック方向く図では右方向）へ移動すると、トラック
コイル６ｂは磁束密度が高い方向へ移動し、トラックコ
イル６ａは磁束密度が低くなる方向へ移動するため、同
一電流を流した場合、各々のコイルに発生する力はトラ
ックコイル６ｂに発生する力がトラックコイル６ａに発
生ずる力より大きくなるため、力のバランスがくずれる
。As shown in FIG. 5(a), when the objective lens 1 is in a stationary state, the pair of track coils 6a and 6b are placed symmetrically on the center line A with respect to the track direction of the magnetic circuit. The balance of forces generated in the track direction is balanced.As shown in FIG. , and the track coil 6a moves in the direction where the magnetic flux density becomes lower. Therefore, when the same current is applied, the force generated in each coil is greater than the force generated in the track coil 6b than the force generated in the track coil 6a. As it becomes larger, the balance of forces is disrupted.
従って、上述した様に磁気ギャップ中で磁束密度が均一
でない磁気回路で同一の巻数で形成した第５図に示す様
な一対のトラックコイルに、同一電流を流して駆動する
と、対物レンズ１がトラック方向へ移動すると一対のト
ラックコイルに発生する力のバランスがくずれるので、
トラック方向に対してのねじり剛性が弱くなるという欠
点がある。Therefore, when the same current is applied to and driven a pair of track coils as shown in FIG. 5, which are formed with the same number of turns in a magnetic circuit in which the magnetic flux density is not uniform in the magnetic gap as described above, the objective lens 1 is When moving in this direction, the balance of forces generated between the pair of track coils will be disrupted, so
The disadvantage is that the torsional rigidity in the track direction is weakened.
本発明の対物レンズ駆動装置は、磁石およびヨークなら
びに磁気ギャップからなる磁気回路と、対物レンズを保
持する可動部と、この可動部に取り付けられ前記磁気ギ
ャップ中に電流を生ずることにより前記可動部をトラッ
ク方向に動かすトラックコイルとを含み、前記磁気ギャ
ップの寸法がトラック方向に対して中心部で最も長く周
辺部で短くし前記磁気ギャップ内の磁束密度がトラック
方向に対し一様であるようにしたことを特徴とする。The objective lens driving device of the present invention includes a magnetic circuit including a magnet, a yoke, and a magnetic gap, a movable part that holds the objective lens, and a movable part that is attached to the movable part and drives the movable part by generating a current in the magnetic gap. a track coil that moves in the track direction, and the dimensions of the magnetic gap are longest at the center and shortest at the periphery in the track direction so that the magnetic flux density within the magnetic gap is uniform in the track direction. It is characterized by
次に、本発明について図面を参照して説明する。 Next, the present invention will be explained with reference to the drawings.
第１図＜ａ）および（ｂ）はそれぞれ本発明の一実施例
の平面図およびＡＡ’断面図である。第２図（ａ、 ）
および（ｂ）はそれぞれ可動部２の平面図および側面図
である。第３図は本発明の詳細な説明するための図であ
る。FIGS. 1A and 1B are a plan view and a sectional view taken along line AA' of an embodiment of the present invention, respectively. Figure 2 (a, )
and (b) are a plan view and a side view of the movable part 2, respectively. FIG. 3 is a diagram for explaining the present invention in detail.
本実施例は、対物レンズ１．可動部２，４本ワイヤ３ａ
、３ｂ、３ｃ、３ｄ、固定部４．フォーカスコイル５．
トラックコイル６ａ、６ｂ。In this embodiment, objective lens 1. Movable part 2, 4 wires 3a
, 3b, 3c, 3d, fixed part 4. Focus coil5.
Track coils 6a, 6b.
６ｃ、６ｄ、磁石７ａ、７ｂ、ヨーク８ｂの部分は第３
図に示す従来の対物レンズ駆動装置と同じ構成であるが
、磁気回路の一部である磁石７ａ。6c, 6d, magnets 7a, 7b, and yoke 8b are the third
Although it has the same configuration as the conventional objective lens drive device shown in the figure, a magnet 7a is part of the magnetic circuit.
７ｂの形状が異っている。すなわち、磁石７ａ。The shape of 7b is different. That is, the magnet 7a.
７ｂのヨーク８ａと対向する面が従来は平面であったの
に対し、本実施例では、磁石７ａ、７ｂの中心部分にお
ける磁気ギャップ９の寸法を磁石７ａ、、７ｂの外周部
におけるものより長くし、磁気ギャップ９中の磁束密度
がトラック方向に対して、常に一定となる様に磁石７ａ
、７ｂを凹面状に形成する。Conventionally, the surface of the magnet 7b facing the yoke 8a was flat, but in this embodiment, the dimension of the magnetic gap 9 at the center of the magnets 7a, 7b is longer than that at the outer periphery of the magnets 7a, 7b. The magnet 7a is arranged so that the magnetic flux density in the magnetic gap 9 is always constant in the track direction.
, 7b are formed in a concave shape.
第３図に、本発明の原理を示す。同図（ａ）には従来の
対物レンズ駆動装置の磁気ギャップ９の構成を示す。す
なわち、磁石７ａから磁束が発生し、磁気ギャップ９．
ヨーク８ａを介して、ヨーク８ｂを通る磁気回路が構成
されている。第２図（ａ＞に示す磁気ギャップ９におけ
るトラック方向に対しての磁束密度の分布１２は図に示
す様に、トラック方向の距離１０に対して磁束密度１１
は磁気ギャップ９の中心部分で高く、周囲部分で低下す
る実験低下を得ている。これは周囲の部分のもれ磁束が
大きくなるためと考えられる。FIG. 3 shows the principle of the invention. FIG. 2A shows the configuration of a magnetic gap 9 of a conventional objective lens driving device. That is, magnetic flux is generated from the magnet 7a, and the magnetic gap 9.
A magnetic circuit is configured that passes through the yoke 8b via the yoke 8a. The magnetic flux density distribution 12 with respect to the track direction in the magnetic gap 9 shown in FIG. 2 (a) is as shown in the figure.
We obtained an experimental decrease in which is high at the center of the magnetic gap 9 and decreases at the periphery. This is thought to be due to the increase in leakage magnetic flux in the surrounding areas.
これに対して、本実施例の対物レンズ駆動装置は同図（
ｂ）に示す様に磁気ギャップ９中でトラック方向の中心
部分の磁気ギャップ９長を外周部よりも長くなるように
磁石７ａ、７ｂを形成し、磁気ギャップ９中の磁束密度
がトラック方向に対して常に一定になっている。On the other hand, the objective lens driving device of this embodiment is shown in the same figure (
As shown in b), the magnets 7a and 7b are formed so that the length of the magnetic gap 9 at the center portion in the track direction is longer than that at the outer periphery, so that the magnetic flux density in the magnetic gap 9 is is always constant.
＝ ５
以上説明したように本発明は、磁気ギャップ中の磁束密
度がトラック方向に対して常に一定であるので、各トラ
ックコイルに同一電流を流して対物レンズをトラック方
向へ移動しても、各トラックコイルに発生ずる力は常に
一定であるがら、力のバランスはくずれない。従って、
トラック方向に対してのねじれ剛性が強くなるので、安
定なザーボ特性が得られる効果がある。= 5 As explained above, in the present invention, since the magnetic flux density in the magnetic gap is always constant in the track direction, even if the same current is passed through each track coil and the objective lens is moved in the track direction, each Although the force generated in the track coil is always constant, the force balance remains unchanged. Therefore,
Since the torsional rigidity in the track direction is increased, stable servo characteristics can be obtained.
３ｃ、３ｄ・・・ワイヤ、４・・・固定部、５・・・フ
ォーカスコイル、６ａ、６ｂ、６ｃ、６ｄ・・・トラッ
クコイル、７ａ、７ｂ＝−磁石、８ａ、８ｂ−・・ヨー
ク、９・・・磁気ギャップ、］０・・・トラック方向の
距離、１１・・・磁束密度、１２・・・磁気ギャップ中
における磁束密度。3c, 3d... Wire, 4... Fixed part, 5... Focus coil, 6a, 6b, 6c, 6d... Track coil, 7a, 7b=-magnet, 8a, 8b-... Yoke, 9...Magnetic gap, ]0...Distance in the track direction, 11...Magnetic flux density, 12...Magnetic flux density in the magnetic gap.
Claims (1)
路と、対物レンズを保持する可動部と、この可動部に取
り付けられ前記磁気ギャップ中に電流を生ずることによ
り前記可動部をトラック方向に動かすトラックコイルと
を含み、前記磁気ギャップの寸法がトラック方向に対し
て中心部で最も長く周辺部で短くし前記磁気ギャップ内
の磁束密度がトラック方向に対し一様であるようにした
ことを特徴とする対物レンズ駆動装置。A magnetic circuit including a magnet, a yoke, and a magnetic gap, a movable part that holds an objective lens, and a track coil that is attached to the movable part and moves the movable part in the track direction by generating a current in the magnetic gap. , an objective lens driving device characterized in that the dimensions of the magnetic gap are longest at the center and shortest at the periphery in the track direction so that the magnetic flux density within the magnetic gap is uniform in the track direction. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24804688A JPH0294123A (en) | 1988-09-30 | 1988-09-30 | Object lens driving device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24804688A JPH0294123A (en) | 1988-09-30 | 1988-09-30 | Object lens driving device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0294123A true JPH0294123A (en) | 1990-04-04 |
Family
ID=17172391
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP24804688A Pending JPH0294123A (en) | 1988-09-30 | 1988-09-30 | Object lens driving device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0294123A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7026902B2 (en) | 2001-09-27 | 2006-04-11 | Samsung Electronics Co., Ltd. | Magnet used with an optical pickup actuator |
| WO2007139012A1 (en) * | 2006-05-30 | 2007-12-06 | Panasonic Corporation | Optical head carrying device, integrated circuit for optical head carrying device, focusing lens driving device and integrated circuit for focusing lens driving device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63129848A (en) * | 1986-11-17 | 1988-06-02 | Toshiba Corp | Linear actuator |
-
1988
- 1988-09-30 JP JP24804688A patent/JPH0294123A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63129848A (en) * | 1986-11-17 | 1988-06-02 | Toshiba Corp | Linear actuator |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7026902B2 (en) | 2001-09-27 | 2006-04-11 | Samsung Electronics Co., Ltd. | Magnet used with an optical pickup actuator |
| KR100772363B1 (en) * | 2001-09-27 | 2007-11-01 | 삼성전자주식회사 | Magnet for optical pickup actuator |
| WO2007139012A1 (en) * | 2006-05-30 | 2007-12-06 | Panasonic Corporation | Optical head carrying device, integrated circuit for optical head carrying device, focusing lens driving device and integrated circuit for focusing lens driving device |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP2002373435A (en) | Actuator for optical pickup | |
| JPH0294123A (en) | Object lens driving device | |
| JP2000011408A (en) | Pickup device of disk player | |
| US4011417A (en) | Dynamic type pickup | |
| KR100218427B1 (en) | An optical pickup actuator | |
| JPH03113732A (en) | Optical system drive device | |
| JPH0454565Y2 (en) | ||
| JPH0287961A (en) | Linear actuator | |
| JP2700005B2 (en) | Objective lens drive | |
| JPH0212618A (en) | Objective lens driving device | |
| JPH0253230A (en) | Optical driving device | |
| KR100218428B1 (en) | An optical pickup actuator | |
| JP2842553B2 (en) | Objective lens drive | |
| JPH1166586A (en) | Optical head actuator | |
| KR19990066900A (en) | Actuator device with optical pickup | |
| JPH04102235A (en) | Objective lens driving device | |
| JPS63114556A (en) | Positioning device | |
| JPH0770077B2 (en) | Objective lens drive | |
| JPH05114152A (en) | Objective lens actuator | |
| JPS63114557A (en) | Positioning device | |
| JPS63114559A (en) | Positioning device | |
| JPS5968834A (en) | Actuator for optical head | |
| JPS62287444A (en) | Lens driving device | |
| JPH0391122A (en) | Objective lens driving device | |
| JPH02226522A (en) | Optical system driver |