JPH0689448A - Driving device for objective lens - Google Patents

Driving device for objective lens

Info

Publication number
JPH0689448A
JPH0689448A JP23847492A JP23847492A JPH0689448A JP H0689448 A JPH0689448 A JP H0689448A JP 23847492 A JP23847492 A JP 23847492A JP 23847492 A JP23847492 A JP 23847492A JP H0689448 A JPH0689448 A JP H0689448A
Authority
JP
Japan
Prior art keywords
coil
yoke
magnetic gap
focusing
magnetic
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.)
Withdrawn
Application number
JP23847492A
Other languages
Japanese (ja)
Inventor
Yoshihiro Sekimoto
芳宏 関本
Toshiharu Inui
敏治 乾
Yasuo Nakada
泰男 中田
Nobuo Ogata
伸夫 緒方
Hideo Sato
秀朗 佐藤
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sharp Corp
Original Assignee
Sharp Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Sharp Corp filed Critical Sharp Corp
Priority to JP23847492A priority Critical patent/JPH0689448A/en
Publication of JPH0689448A publication Critical patent/JPH0689448A/en
Withdrawn legal-status Critical Current

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  • Optical Recording Or Reproduction (AREA)

Abstract

PURPOSE:To suppress the generation of the unwanted angular moment of a coil located outside a magnetic gap due to leaked magnetic flux and to make the device small in size by thickening only the thickness of a yoke facing a focusing coil outside a magnetic gap thicker than other parts by sticking an outside plate. CONSTITUTION:A lens holder 3 for holding an objective lens 2 is supported by an elestic body 5 so as to be movable in two directions and a focusing coil 6 and a tracking coil 7 are fixed into a hole at the central section of the holder 3. Some portions of the coils 6, 7 are arranged within the magnetic gap 9 of a magnetic circuit 8 extended from a fixing part 4 and the circuit 8 is composed of parmanent magnets 10a, 10b and a U-shaped yoke composed of yoke feet 11a, 11b mounted inside the magnets. The coil 6 is wound so as to surround the magnet 10a, the foot 11a and a outside plate of yoke 11c provided only on the foot 11a and a coil 6a which is a part unnecessary for generating driving force is located outside the gap 9. Consequently, angular moment caused by the action of the coil 6a is suppressed, the resonant peak is improved to be small and the miniaturization of the device is attained.

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【産業上の利用分野】本発明は、記録媒体に光ビームを
照射することによって、情報を光学的に記録,再生,ま
たは消去をすることができる光学的情報記録再生装置等
に配備される対物レンズ駆動装置に関するものである。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an objective provided in an optical information recording / reproducing apparatus capable of optically recording, reproducing, or erasing information by irradiating a recording medium with a light beam. The present invention relates to a lens driving device.

【0002】[0002]

【従来の技術】従来、対物レンズを介して光磁気ディス
ク等の情報記録媒体に照射される光ビームの集光位置
を、フォーカシング方向およびトラッキング方向に制御
するために、対物レンズを2軸駆動する対物レンズ駆動
装置が知られている。
2. Description of the Related Art Conventionally, an objective lens is biaxially driven in order to control a focusing position of a light beam applied to an information recording medium such as a magneto-optical disk through the objective lens in a focusing direction and a tracking direction. Objective lens drive devices are known.

【0003】図4はこのような対物レンズ駆動装置の一
例の斜視図である。対物レンズ駆動装置51には、対物
レンズ52を保持するレンズホルダ53が設けられてい
る。レンズホルダ53の両側面には、レンズホルダ53
を固定部54に対して2方向に可動に支持する弾性体5
5が上下にそれぞれ取付けられており、レンズホルダ5
3の中央部の孔には、フォーカシングコイル56および
トラッキングコイル57が固着されている。フォーカシ
ングコイル56は、レンズホルダ53を図の固定部に対
し垂直方向矢印A方向に動かし、トラッキングコイル5
7はレンズホルダ53を図の固定部に対し水平方向矢印
B方向に動かす。
FIG. 4 is a perspective view of an example of such an objective lens driving device. The objective lens driving device 51 is provided with a lens holder 53 that holds the objective lens 52. The lens holder 53 is provided on both sides of the lens holder 53.
Elastic body 5 for movably supporting the fixed portion 54 in two directions
5 are attached to the top and bottom respectively, and the lens holder 5
The focusing coil 56 and the tracking coil 57 are fixed to the hole at the center of the No. 3. The focusing coil 56 moves the lens holder 53 in the vertical arrow A direction with respect to the fixed portion in the drawing, and the tracking coil 5 is moved.
7 moves the lens holder 53 in the horizontal arrow B direction with respect to the fixed portion in the figure.

【0004】フォーカシングコイル56およびトラッキ
ングコイル57の一部は、固定部54から延びた磁気回
路58の磁気ギャップ59の中に配置され、磁気回路5
8は永久磁石60a,60bおよびそれらを内側に取付
けたU字状のヨーク61から構成されている。61aお
よび61bはヨーク61の脚である。フォーカシングコ
イル56は、対物レンズ52から遠い方の永久磁石60
aおよびその外側のヨーク脚61aを囲むように巻かれ
ており、駆動力を発生するのに不要な部分56aは磁気
ギャップ59の外に位置するようになっている。
A part of the focusing coil 56 and the tracking coil 57 is arranged in the magnetic gap 59 of the magnetic circuit 58 extending from the fixed portion 54, and the magnetic circuit 5 is provided.
Reference numeral 8 is composed of permanent magnets 60a and 60b and a U-shaped yoke 61 having them attached inside. 61a and 61b are legs of the yoke 61. The focusing coil 56 includes a permanent magnet 60 located farther from the objective lens 52.
It is wound so as to surround a and the yoke leg 61a on the outside thereof, and an unnecessary portion 56a for generating a driving force is located outside the magnetic gap 59.

【0005】[0005]

【発明が解決しようとする課題】ところが、上記の従来
の構造では、ヨーク脚61aの背面から漏れた磁束がフ
ォーカシングコイル56の磁気ギャップ59の外に位置
する部分56aに作用して、レンズホルダ53に対して
図5矢印のように回転モーメントが働き、図6(a),
(b)に示すような周波数特性上に共振ピークが生じる
ようになる。図6(a)は周波数とゲインに関するグラ
フであり、同図(b)は周波数と位相に関するグラフで
ある。
However, in the above-mentioned conventional structure, the magnetic flux leaking from the back surface of the yoke leg 61a acts on the portion 56a of the focusing coil 56 located outside the magnetic gap 59, and the lens holder 53 is covered. On the other hand, the rotation moment acts as shown by the arrow in FIG.
A resonance peak appears on the frequency characteristic as shown in (b). FIG. 6A is a graph relating to frequency and gain, and FIG. 6B is a graph relating to frequency and phase.

【0006】ヨーク脚61aの背面からの磁束の漏れを
減少させるためには、ヨーク61の厚さを大きくするこ
とや、両ヨーク脚61a,61b間を十分な厚さの強磁
性体で橋渡しして箱型にする等により飽和を防ぐことが
有効であるが、ヨーク61全体を厚くしたりあるいは厚
さの大きい強磁性体で箱型にしてヨーク61を高くして
しまうと、装置の小型化,薄型化が困難になってしま
う。
In order to reduce the leakage of the magnetic flux from the rear surface of the yoke leg 61a, the thickness of the yoke 61 is increased or the yoke legs 61a and 61b are bridged by a ferromagnetic material having a sufficient thickness. It is effective to prevent the saturation by making it into a box shape, but if the whole yoke 61 is made thicker or the ferromagnetic material having a large thickness is made into a box shape and the yoke 61 is made higher, the device becomes smaller. , It becomes difficult to reduce the thickness.

【0007】[0007]

【課題を解決するための手段】本発明による対物レンズ
駆動装置は、光ビームを集束して記録媒体に照射する集
光手段と、上記集光手段を保持する保持手段と、上記光
ビームの記録媒体に対する照射位置を少なくともフォー
カシング方向に制御するために、上記保持手段をフォー
カシング方向に変位させるコイル,ヨークおよび永久磁
石等からなる磁気回路を有するフォーカシング駆動手段
を備え、上記コイルは、その一部が上記磁気回路の磁気
ギャップ内に配置されるとともに、一部は磁気ギャップ
外で少なくともヨークを囲むように巻かれており、上記
コイルの磁気ギャップの外に位置する側の部分に面する
ヨークの厚さをヨークの他の部分よりも厚くした。
An objective lens driving device according to the present invention comprises a focusing means for focusing a light beam and irradiating the recording medium, a holding means for holding the focusing means, and a recording of the light beam. In order to control the irradiation position with respect to the medium at least in the focusing direction, a focusing driving means having a magnetic circuit composed of a coil, a yoke, a permanent magnet and the like for displacing the holding means in the focusing direction is provided, and the coil has a part thereof. The thickness of the yoke that is arranged in the magnetic gap of the magnetic circuit and is partially wound outside the magnetic gap so as to surround the yoke, and faces the portion of the coil that is located outside the magnetic gap. Thicker than the rest of the yoke.

【0008】[0008]

【作用】以上のようにすることにより、フォーカシング
コイルのうち、磁気ギャップの外に位置している部分に
作用する漏れ磁束の量を減らすことができるとともに、
ヨーク全体を厚くしたり、大きくしたりしていないた
め、装置の小型化,薄型化が可能である。
By the above, the amount of leakage magnetic flux acting on the portion of the focusing coil located outside the magnetic gap can be reduced, and at the same time,
Since the entire yoke is not made thick or large, the device can be made smaller and thinner.

【0009】[0009]

【実施例】図1は、本発明による一実施例の斜視図であ
り、全体の構成は図4の従来例とほぼ同じである。図1
の各符号は、図4の各符号から50を減じたものであ
る。
FIG. 1 is a perspective view of an embodiment according to the present invention, and the overall structure is almost the same as that of the conventional example of FIG. Figure 1
The reference numerals in FIG. 4 are obtained by subtracting 50 from the reference numerals in FIG.

【0010】対物レンズ2を保持するレンズホルダ3が
設けられ、レンズホルダ3の両側面には、レンズホルダ
3を固定部4に対して2方向に可動に支持する弾性体5
が上下にそれぞれ取付けられており、レンズホルダ3の
中央部の孔にはフォーカシングコイル6およびトラッキ
ングコイル7が固着されている。フォーカシングコイル
6およびトラッキングコイル7の一部は、固定部4から
延びた磁気回路8の磁気ギャップ9の中に配置され、磁
気回路8は永久磁石10a,10bおよびこれらを内側
に取付けたU字状のヨーク11から構成されている。ヨ
ーク11はヨーク脚11aおよび11bを備えている。
フォーカシングコイル6は一方の永久磁石10aおよび
ヨーク脚11a,ヨーク外板11cを囲むように巻かれ
ており、駆動力を発生するのに不要な部分6aは磁気ギ
ャップ9の外に位置するようになっている。
A lens holder 3 for holding the objective lens 2 is provided, and elastic bodies 5 for movably supporting the lens holder 3 in two directions with respect to a fixed portion 4 are provided on both side surfaces of the lens holder 3.
Are attached to the upper and lower sides, respectively, and the focusing coil 6 and the tracking coil 7 are fixed to the central hole of the lens holder 3. A part of the focusing coil 6 and the tracking coil 7 is arranged in the magnetic gap 9 of the magnetic circuit 8 extending from the fixed portion 4, and the magnetic circuit 8 has permanent magnets 10a and 10b and a U-shape in which these are attached. It is composed of a yoke 11. The yoke 11 includes yoke legs 11a and 11b.
The focusing coil 6 is wound so as to surround one permanent magnet 10a, the yoke leg 11a, and the yoke outer plate 11c, and the unnecessary portion 6a for generating a driving force is located outside the magnetic gap 9. ing.

【0011】図4の従来例と異なるところは、フォーカ
シングコイル6に囲まれた側のヨークの厚さがヨーク脚
11aとその外側のヨーク外板11cによりヨーク11
の他の部分に比べて厚くなっていることである。
The difference from the conventional example of FIG. 4 is that the thickness of the yoke on the side surrounded by the focusing coil 6 is such that the yoke leg 11a and the yoke outer plate 11c on the outer side of the yoke leg 11a make the thickness of the yoke 11 smaller.
It is thicker than other parts.

【0012】ヨーク11のフォーカシングコイルに囲ま
れる部分に外側を厚くする構成例としては、図2(a)
に示すようなヨーク脚11aが厚くなるような形状にヨ
ーク11を削り出し、または焼結によって作成するか、
図2(b)のように板金を曲げてヨーク11が構成され
ている場合には、ヨーク脚11aの背面に別の強磁性体
よりなる薄板のヨーク外板11cを張り付けることなど
が考えられる。図1はこの場合である。
As an example of the structure in which the outer side of the yoke 11 is surrounded by the focusing coil, the thickness is increased as shown in FIG.
The yoke 11 is machined into a shape such that the yoke leg 11a is thickened, or is formed by sintering, or
When the yoke 11 is formed by bending a metal plate as shown in FIG. 2B, it is conceivable to attach a thin yoke outer plate 11c made of another ferromagnetic material to the back surface of the yoke leg 11a. . FIG. 1 shows this case.

【0013】このように、磁気ギャップ9の外に位置す
る部分のフォーカシングコイル6aに作用する力を小さ
くして、回転モーメントを抑えることにより、フォーカ
シング方向の周波数特性は図3(a)および(b)のよ
うに共振ピークを小さく改善することができる。図3
(a)および(b)はそれぞれ図6(a)および(b)
に対応するものである。
As described above, the force acting on the focusing coil 6a located outside the magnetic gap 9 is reduced to suppress the rotation moment, so that the frequency characteristics in the focusing direction are shown in FIGS. 3 (a) and 3 (b). ), The resonance peak can be improved to be small. Figure 3
6 (a) and 6 (b) are shown in FIGS. 6 (a) and 6 (b), respectively.
It corresponds to.

【0014】なお、上記実施例ではヨーク脚11aおよ
び11bにそれぞれ永久磁石10aおよび10bが固着
されているものについて説明したが、永久磁石がヨーク
脚11aに固着されていない構造でも同様の効果を奏す
る。
Although the permanent magnets 10a and 10b are fixed to the yoke legs 11a and 11b, respectively, in the above embodiment, the same effect can be obtained even if the permanent magnets are not fixed to the yoke legs 11a. .

【0015】[0015]

【発明の効果】本発明による対物レンズ駆動装置は、以
上のような構造であるから、フォーカシングコイルのう
ち磁気ギャップの外に位置している部分に作用する漏れ
磁束の量を減らして、レンズホルダに対する回転モーメ
ントの発生を抑えることができるとともに、ヨーク全体
を厚くしたり、大きくしたりしていないため、小型薄型
の装置を供給できる。
Since the objective lens driving device according to the present invention has the above-described structure, the amount of leakage magnetic flux acting on the portion of the focusing coil located outside the magnetic gap is reduced, and the lens holder is reduced. It is possible to suppress the generation of a rotational moment with respect to the above, and since the yoke as a whole is not made thick or large, it is possible to supply a small and thin device.

【図面の簡単な説明】[Brief description of drawings]

【図1】本発明の一実施例の斜視図である。FIG. 1 is a perspective view of an embodiment of the present invention.

【図2】(a)および(b)は、それぞれ本発明の実施
例の側断面図である。
2 (a) and 2 (b) are side sectional views of an embodiment of the present invention.

【図3】(a)および(b)は、それぞれ周波数対ゲイ
ンおよび周波数対位相のグラフである。
3A and 3B are graphs of frequency versus gain and frequency versus phase, respectively.

【図4】従来の一例の斜視図である。FIG. 4 is a perspective view of a conventional example.

【図5】図4の磁気回路の側断面図である。5 is a side cross-sectional view of the magnetic circuit of FIG.

【図6】(a)および(b)はそれぞれ従来の装置にお
けるフォーカシング方向の周波数対ゲインおよび周波数
対位相のグラフである。
6A and 6B are graphs of frequency vs. gain and frequency vs. phase in the focusing direction in a conventional device, respectively.

【符号の説明】[Explanation of symbols]

1 対物レンズ駆動装置 2 対物レンズ 3 レンズホルダ 4 固定部 5 弾性体 6 フォーカシングコイル 7 トラッキングコイル 8 磁気回路 10 永久磁石 11 ヨーク 1 Objective Lens Driving Device 2 Objective Lens 3 Lens Holder 4 Fixed Part 5 Elastic Body 6 Focusing Coil 7 Tracking Coil 8 Magnetic Circuit 10 Permanent Magnet 11 Yoke

───────────────────────────────────────────────────── フロントページの続き (72)発明者 緒方 伸夫 大阪府大阪市阿倍野区長池町22番22号 シ ャープ株式会社内 (72)発明者 佐藤 秀朗 大阪府大阪市阿倍野区長池町22番22号 シ ャープ株式会社内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobuo Ogata 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Sharp Corporation (72) Hidero Sato 22-22 Nagaike-cho, Abeno-ku, Osaka, Osaka Within the corporation

Claims (1)

【特許請求の範囲】[Claims] 【請求項1】 光ビームを集束して記録媒体に照射する
集光手段と、上記集光手段を保持する保持手段と、上記
光ビームの記録媒体に対する照射位置を少なくともフォ
ーカシング方向に制御するために上記保持手段をフォー
カシング方向に変位させるコイル,ヨークおよび永久磁
石等からなる磁気回路を有するフォーカシング駆動手段
とを備え、 上記コイルは、その一部が上記磁気回路の磁気ギャップ
内に配置されるとともに、一部は磁気ギャップ外で少な
くともヨークを囲むように巻かれており、上記コイルの
磁気ギャップの外に位置する側の部分に面するヨークの
厚さを、ヨークの他の部分よりも厚くしたことを特徴と
する対物レンズ駆動装置。
1. A light condensing means for converging a light beam to irradiate a recording medium, a holding means for holding the light condensing means, and an irradiation position of the light beam on the recording medium for controlling at least a focusing direction. A coil for displacing the holding means in the focusing direction, a focusing drive means having a magnetic circuit composed of a yoke, a permanent magnet and the like, and a part of the coil is arranged in a magnetic gap of the magnetic circuit, and Part of the coil is wound outside the magnetic gap so as to surround at least the yoke, and the thickness of the yoke facing the part of the coil located outside the magnetic gap is made thicker than the other parts of the yoke. An objective lens driving device characterized by:
JP23847492A 1992-09-07 1992-09-07 Driving device for objective lens Withdrawn JPH0689448A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP23847492A JPH0689448A (en) 1992-09-07 1992-09-07 Driving device for objective lens

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP23847492A JPH0689448A (en) 1992-09-07 1992-09-07 Driving device for objective lens

Publications (1)

Publication Number Publication Date
JPH0689448A true JPH0689448A (en) 1994-03-29

Family

ID=17030781

Family Applications (1)

Application Number Title Priority Date Filing Date
JP23847492A Withdrawn JPH0689448A (en) 1992-09-07 1992-09-07 Driving device for objective lens

Country Status (1)

Country Link
JP (1) JPH0689448A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7076791B2 (en) 2001-12-21 2006-07-11 Hitachi Ltd Optical pickup and optical disc apparatus provided with the same
WO2011021489A1 (en) * 2009-08-20 2011-02-24 アルプス電気株式会社 Lens drive device

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7076791B2 (en) 2001-12-21 2006-07-11 Hitachi Ltd Optical pickup and optical disc apparatus provided with the same
WO2011021489A1 (en) * 2009-08-20 2011-02-24 アルプス電気株式会社 Lens drive device
JPWO2011021489A1 (en) * 2009-08-20 2013-01-24 アルプス電気株式会社 Lens drive device

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Legal Events

Date Code Title Description
A300 Withdrawal of application because of no request for examination

Free format text: JAPANESE INTERMEDIATE CODE: A300

Effective date: 19991130