JP4324368B2

JP4324368B2 - Lens drive device

Info

Publication number: JP4324368B2
Application number: JP2002340120A
Authority: JP
Inventors: 守正吉江; 陽介千代原
Original assignee: Shicoh Co Ltd
Current assignee: Shicoh Co Ltd
Priority date: 2002-10-18
Filing date: 2002-10-18
Publication date: 2009-09-02
Anticipated expiration: 2022-10-18
Also published as: JP2004138992A

Description

【０００１】
【発明の属する技術分野】
本発明は、携帯型小形カメラに用いられ、被写像をズームするレンズ駆動装置に関する。
【０００２】
【従来の技術】
この種のレンズ駆動装置としては、ステッピングモータと送りねじ伝動機構との組合せによる装置が知られており、このレンズ駆動装置を図５に示す。
図５に示す様に、レンズ駆動装置１００は、回転するステッピングモータ１０１のシャフトを歯車１０２を介して送りねじ１０３に伝達して、回転運動を直運動に変換している。送りねじ１０３上を案内駆動されるナット１０４上には、レンズ１０５が固定されている。従って、ステッピングモータ１０１の回転角度に従って、レンズ１０５の直線位置が決定される。
【０００３】
【発明が解決しようとする課題】
しかし、上述の技術では、ステッピングモータ１０１、歯車１０２、送りねじ１０３及びナット１０４と言った複雑な伝動機構が必要となるので、装置が大形となり且つ、レンズ１０５の位置の精度が悪いという課題がある。
【０００４】
そこで、本発明は、小型軽量で且つ、レンズを直線移動させても位置精度の良いレンズ駆動装置を提供することを目的とする。
【０００５】
【課題を解決するための手段】
請求項１に記載の発明は、前方レンズと、前方レンズを支持する前方レンズ枠と、前方レンズ枠を支持する前方支持体と、前方支持体に取り付けられる前方コイルと、前方支持体に取り付けられる前方バネと、後方レンズと、後方レンズを支持する後方支持体と、後方支持体に取り付けられる後方コイルと、後方支持体に取り付けられる後方バネと、マグネットと、マグネット支持体と、内壁と外壁とを筒状に形成して底壁で連結したヨークとを備え、マグネット支持体はヨークの内壁と外壁との間に設けてこれらの各壁との間に隙間をあけてマグネットを配置しており、マグネットはラジアル方向に磁化してあり、前方コイルは、マグネットとヨーク外壁との間の外側ギャップに周方向に巻回して配置し、後方コイルは、マグネットとヨーク内壁との間の内側ギャップに周方向に巻回して配置し、前方コイルに電流を印加することによって前側レンズに前後方向の駆動力を付与し、前方レンズを前方バネの弾性力と釣合う位置に移動させ、後方コイルに電流を印加することによって後側レンズに前後方向の駆動力を付与し、後方レンズを後方バネの弾性力と釣合う位置に移動させるレンズ駆動装置であって、前方バネ及び後方バネは各々、略半円状の内周側部と外周側部とを有し、内周側部と外周側部は周方向の一端が連結してあり、内周側部の周方向の他端である内端部と外周側部の周方向の他端である外端部とを有する板バネを２つ組合わせて略リング状としてあり、各板バネは組付け前は平坦であり、組付け時に内端部と外端部とで段差を生じる様に伸ばして弾性変形した状態で組付けてあり、前方バネは外端部が前方支持体の前端に固着され内端部がマグネット支持体の前端に固着されており、後方バネは内端部がマグネット支持体の後端に固着され外端部が後方支持体の後端に固着されていることを特徴とする。
【０００６】
この請求項１に記載の発明では、ヨークの内壁と外壁との間にこれらと隙間をあけてラジアル方向に磁化したマグネットを配置し、各隙間に対応する前方コイルと後方コイルをヨークの周方向に巻回してヨーク内に配置しているので、装置の構造を小型なものにすることができる。更に、前方コイル及び後方コイルに印加する電流によって生じる各レンズの前後方向の駆動力と両バネの弾性力とが釣合う位置に移動させているので、それぞれのコイルに流す電流量だけで、移動量を決定することができる。これによって、装置の構造を更に小形なものにすることができる。尚、図５に示す従来技術に比較して、モータ１０１、歯車１０２、送りねじ１０３を用いていないので、装置が小型軽量であり、歯車やねじのがたがないので位置精度が良い。
前方バネ及び後方バネは、伸ばされて組立てられる構造としたので、バネ定数の初期歪を避けることができる。
【０００７】
請求項２に記載の発明は、請求項１に記載の発明において、前方バネを前方コイルへの給電経路としてあり、後方バネを後方コイルへの供電経路としてあることを特徴とする。
【０００８】
【０００９】
【発明の実施の形態】
以下、添付した図面を参照しながら、本発明の実施の形態を説明する。
図１は、本発明に係るレンズ駆動装置を示す断面図であり、図２は図１のレンズ駆動装置の６０度異なる断面を示す断面図であり、図３は図１のレンズ駆動装置の分解斜視図であり、図４は、図１のレンズ駆動装置の動作を示す断面図である。
【００１０】
レンズ駆動装置１は、前方レンズ２と、前方レンズ枠３１と、前方支持体３と、前方コイル４と前方バネ５と、後方レンズ６と、後方支持体７と、後方コイル８と、後方バネ９と、マグネット１０と、マグネット支持体２１と、ヨーク１１とを備えており、前方コイル４はマグネット１０とヨーク１１間の外側ギャップに周方向に巻回して配置し、後方コイル８はマグネット１０とヨーク１１間の内側ギャップに周方向に巻回して配置し、前方コイル４に直流電流を印加することにより、前方レンズ２に前方の駆動力を付与して移動し、後方コイル８に直流電流を印加することにより、後方レンズ６に前方の駆動力を付与して移動する様になっている。尚、本明細書においては、前方及び後方の文言を適宜、使用するが、これはカメラから被写体に向って、相対的に前方及び後方の位置関係を表わすものである。
【００１１】
リング状Ｄ前方支持体３は合成樹脂等の成形品（電気的絶縁体）であり、上部で前方レンズ枠３１を支持し、外周後方に前方コイル４を備え、最前方部分の突起には、前方バネ５の外端部５ａが固着されており、内周部後方部分の９０度毎４個所に突起２２を設けて抜け止めとして作用させていると共に、最後尾には小さな突起であるリブ２３を備えて、マグネット支持体２１の外周部との摺動を行わせている。前方コイル４のリード線は、前方支持体３の外周部分の溝を通って、最前方部分の突起の近傍で前方バネ５の外端部５ａに半田付接続される。前方レンズ枠３１は、内周部分で前方レンズ２を支持している。
【００１２】
同様に、リング状の後方支持体７は、合成樹脂等の成形品（電気的絶縁体）であり、中央部で後方レンズ６を支持し、内周部と腕部７ａの間に後方コイル８を備え、後方部の底面上の突起には後方バネ９の内端部９ｂが固着されている。
【００１３】
リング状のヨーク１１は、軟鉄等の磁性体であり、外壁１１ａと内壁１１ｂ及び底面１１ｃから成る形状を有し、外壁１１ａは内壁１１ｂより壁高が大であり、内壁１１ｂには９０度間隔で４個所の切欠１１ｄを備え、後方支持枠７の腕部７ａは切欠１１ｄを貫通している。
【００１４】
マグネット支持体２１は合成樹脂等の成形品（電気的絶縁体）であり、上下のリングを４本の支柱が支える籠形状とし、４本の支柱の間には、４個のマグネット１０がハメ込まれて支持されている。量産時には一体成形で製作すると好都合である。マグネット１０は、矩形の円弧形状の同一の４片から成り、ラジアル方向に磁化されており、マグネット支持体２１の籠形状は、マグネット１０の反発力に対抗できる構造の堅固さを確保している。
【００１５】
マグネット支持体２１は、底部でヨーク１１の底部１１ｃに勘合固定され、最前方部分の突起には、前方バネ５の内端部５ｂが固着され、本突起の近傍の内周部分に縦溝２１ａを備えている。縦溝２１ａには、金属性の前方端子３２が挿入されており、最前方部分で前方バネ５の内端部５ｂと半田付接続され、前後方部分は、ヨーク１１の底面１１ｃを貫通して前方コイル４への給電端子として作用する。周辺部の外周上端部には突部２１ｃを備えて、前方支持体３の突起２２と突き当たる抜け止めとして作用し、また、突起２１ｃの側面部は、前方バネ５に対して径方向の衝撃から掛る変位を機械的に抑える構造となっている。周辺部の内周部（４個所）には、細長のリブを設け、後方支持体７の外周部との摺動を容易にしている。
【００１６】
後方コイル８のリード線は、腕部７ａの側面に沿って切欠１１ｄを貫通して、後方バネ９の内端部９ｂに半田付接続される。後方バネ９の外端部９ａは、マグネット支持体２１の最後方底部の突起に固着され、バネ押さえと共に給電端子として作用する。
【００１７】
前方コイル４は、マグネット１０と外壁１１ａから成る外側ギャップ間に配置されており、同様に後方コイル８は、マグネット１０と内壁１１ｂから成る内側ギャップ間に配置されており、マグネット１０から外壁１１ａ、底面１１ｃ、内壁１１ｂを経由してマグネット１０に戻る磁路を形成している。
【００１８】
前方バネ５及び後方バネ９は、リン青銅等金属性の板バネであり、バネ性を持つと共に、前方コイル４及び後方コイル８への給電経路としても作用している。前方バネ５の外端部５ａは前方支持体３の突起にハメ込まれてバネ押さえ５ａａで押さえて固着（熱カシメ）され、内端部５ｂはマグネット支持体２１の突起にハメ込まれてバネ押さえ５ｂｂで押さえて固着される。前方支持体３をヨーク１１に挿入する時点で、前方支持体３のフランジ部３ａがヨーク１１の外壁１１ａの上面部に突き当たることによって、外端部５ａと内端部５ｂ間に段差が生じ、前方バネ５は伸ばされて組立てられる。バネ押さえ５ｂｂは、内周方向に突出した形状とされ、後方支持体７に対する抜け止めの役割をも担っている。
前方バネ５及び後方バネ９は各々、略半円状の内周側部と外周側部とを有し、内周側部と外周側部は周方向の一端が連結してあり、内周側部の周方向の他端である内端部と外周側部の周方向の他端である外端部とを有する板バネを２つ組合わせて略リング状としてある。
【００１９】
後方バネ９の外端部９ａは、マグネット支持体２１の突起にハメ込まれてバネ押さえ９ａａで押さえて固着され、内端部９ｂは後方支持体７の突起にハメ込まれてバネ押さえ９ｂｂで押さえて固着される。後方支持体７をヨーク１１に挿入する時点で、後方支持体７の突起部７ｂ（４個所）がヨーク１１の底面１１ｃに突き当たることによって、外端部９ａと内端部９ｂ間に段差が生じ、後方バネ９も伸ばされて組立てられている。この様に、前方バネ５及び後方バネ９は、最後方に納められた状態でも伸ばされて組立てられているので、板バネに固有のバネ定数の初期歪を避けることができる。
【００２０】
次に、上述した構成に基づき、本実施の形態の作用を説明する。レンズ駆動装置１を組立てるには、先ず最初に、前方コイル４を前方支持体３に組込み、後方レンズ６と後方コイル８を後方支持体７に組込んで、それぞれを固着する。前方コイル４のリード線は、予め前方支持体３の２箇所の外周凹部内に沿わせて固着し、引出しておく。また、マグネット１０をマグネット支持体２１に組込んでおく。
【００２１】
次に、後方支持体７をマグネット支持体２１に組込み、後方バネ９及びバネ押さえ９ａａ，９ｂｂを取付け、続いて前方支持体３と前方端子３２をマグネット支持体２１に組込み、前方バネ５及びバネ押さえ５ａａ，５ｂｂを取り付ける。後方コイル８のリード線及び前方コイル４のリード線はそれぞれ内端部９ｂ、外端部５ａに半田付接続し、前方端子３２も半田付接続する。
【００２２】
引続き、ヨーク１１をマグネット支持体２１に組込み、底面１１ｃ部分で固定（圧入）する。前方レンズ２は予め、前方レンズ枠３１に組込んでおき、前方レンズ枠３１をマグネット支持体２１の最前方部分に固着する。
【００２３】
上述した組立結線によって、ヨーク１１の底面１１ｃの貫通孔部分に、前方コイル４への２個の外部入力が２個の前方端子３２として得られ、後方コイル８への２個の外部入力は、後方バネ９の２個の外端部９ａとして得られる。
【００２４】
図４は、前方コイル４及び、後方コイル８に直流電流を印加して、レンズ駆動装置１をズーム状態に作動させた時の断面図を示している。
【００２５】
前方コイル４に電流が印加されると、前方レンズ２に前方（図４では、上方）への電磁力が働くが、前方バネ５の弾性力は変位に比例して後方（図４では、下方）へ働く。従って、前方レンズ２の位置即ち前方への移動距離は、電磁力と弾性力が釣合った点となる。
【００２６】
これによって、前方コイル４に印加する電流量によって、前方レンズ２の移動量を決定することができる。同様に、後方コイル８に印加する電流量によって、後方レンズ６の移動量を決定することができる。
【００２７】
即ち、前方コイル４及び後方コイル８に印加するそれぞれの電流量によって、前方レンズ２及び後方レンズ６それぞれの移動量を決定することができるので、後方レンズ６の更に後方（図４では、下方）のカメラ内部に位置する固定レンズの作用と共に、ＣＣＤなどによる像平面上に、被写体像をズームしてフォーカスさせることができる。
【００２８】
後方支持体７は、内周部と腕部７ａの間に後方コイル８を備え、後方コイル８の２本のリード線は、腕部７ａの側面に沿って切欠１１ｄを貫通して２個の後方バネ９の内端部９ｂｂに接続する構造としたので、後方支持体７をマグネットの内側に配置することができ、小形な構造を実現している。
【００２９】
前方支持体３は、突起２２の最後尾部分で、９０度間隔４個所で極く小さな突起であるリブ２３を備えてマグネット支持体２１の外周部と摺動する。４個のリブ２３は対抗配置となるので精度良く成形でき且つ、摺動面積が小さいので、前方レンズ２のスムーズでブレの少ない移動を実現している。
【００３０】
マグネット支持体２１は、外周上端部に突部２１ｃを備え、前方支持枠３の突起２２と突き当たる抜け止めとして作用し、前方支持体３の脱落を防止すると共に、突起２１ｃの側面部は、前方バネ５に対して径方向の衝撃から掛る変位を機械的に抑える構造となっている。
【００３１】
また、マグネット支持体２１は、上下のリングを４本の支柱が支える籠形状としたので、マグネット１０の反発力に対して堅固な構造を実現している。
【００３２】
更に、前方バネ５及び後方バネ９は、最後方に納められた状態でも伸ばされて組立てられる様にしたので、バネ定数の初期歪を避けることができる。
【００３３】
【発明の効果】
請求項１に記載の発明では、後方レンズをマグネットの内側に配置することができ且つ、印加する電流量を制御することによって、前方レンズ及び後方レンズ、それぞれの移動量を制御できるので、装置の構造を小形で廉価なものにすることができると共に、強度を向上することができる。
【００３４】
請求項２に記載の発明では、請求項１に記載の発明と同様な効果を奏すると共に、バネ定数の歪を抑制して前方レンズ及び後方レンズの位置の精度を向上することができる。
【図面の簡単な説明】
【図１】本発明に係るレンズ駆動装置を示す断面図である。
【図２】図１のレンズ駆動装置の６０度異なる断面を示す断面図である。
【図３】図１のレンズ駆動装置の分解斜視図である。
【図４】図１のレンズ駆動装置の動作を示す断面図である。
【図５】従来に係るレンズ駆動装置を示す斜視図である。
【符号の説明】
１レンズ駆動装置
２前方レンズ
３前方支持体
４前方コイル
５前方バネ
６後方レンズ
７後方支持体
８後方コイル
９後方バネ
１０マグネット
１１ヨーク
２１マグネット支持体
３１前方レンズ枠[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lens driving device that is used in a portable small camera and zooms an object.
[0002]
[Prior art]
As this type of lens driving device, a device using a combination of a stepping motor and a feed screw transmission mechanism is known, and this lens driving device is shown in FIG.
As shown in FIG. 5, the lens driving device 100 transmits the shaft of the rotating stepping motor 101 to the feed screw 103 via the gear 102 to convert the rotational motion into a linear motion. A lens 105 is fixed on a nut 104 guided and driven on the feed screw 103. Therefore, the linear position of the lens 105 is determined according to the rotation angle of the stepping motor 101.
[0003]
[Problems to be solved by the invention]
However, the above-described technique requires complicated transmission mechanisms such as the stepping motor 101, the gear 102, the feed screw 103, and the nut 104, so that the apparatus becomes large and the accuracy of the position of the lens 105 is poor. There is.
[0004]
SUMMARY OF THE INVENTION An object of the present invention is to provide a lens driving device that is small and light and has good positional accuracy even when the lens is linearly moved.
[0005]
[Means for Solving the Problems]
The invention according to claim 1 is attached to the front lens, the front lens frame that supports the front lens, the front support that supports the front lens frame, the front coil that is attached to the front support, and the front support. A front spring, a rear lens, a rear support for supporting the rear lens, a rear coil attached to the rear support, a rear spring attached to the rear support, a magnet, a magnet support, an inner wall and an outer wall; The magnet support is provided between the inner wall and the outer wall of the yoke, and a magnet is arranged with a gap between each wall. , magnet Yes magnetized in the radial direction, the forward coil, arranged wound around the outer gap in the circumferential direction between the magnet and the yoke outer wall, the rear coil, magnet and yaw Wound inside the gap in the circumferential direction between the inner wall and disposed to impart longitudinal direction of the driving force to the front lens by applying a current to the forward coil, position balance the front lens and the elastic force of the front spring A lens driving device that applies a current to the rear coil to apply a driving force in the front-rear direction to the rear lens, and moves the rear lens to a position that balances the elastic force of the rear spring. And the rear spring each have a substantially semicircular inner peripheral side portion and an outer peripheral side portion, and the inner peripheral side portion and the outer peripheral side portion are connected at one end in the circumferential direction, and the circumferential direction of the inner peripheral side portion Two leaf springs having an inner end that is the other end and an outer end that is the other end in the circumferential direction of the outer peripheral side are combined into a substantially ring shape, and each leaf spring is flat before assembly. Yes, and stretched to create a step between the inner and outer ends when assembled and elastically deformed The front end of the front spring is fixed to the front end of the front support, the inner end is fixed to the front end of the magnet support, and the rear end of the rear spring is the rear end of the magnet support. And the outer end portion is fixed to the rear end of the rear support.
[0006]
In the first aspect of the present invention, magnets magnetized in the radial direction with a gap therebetween are arranged between the inner wall and the outer wall of the yoke, and the front coil and the rear coil corresponding to each gap are arranged in the circumferential direction of the yoke. Since it is wound around and arranged in the yoke, the structure of the apparatus can be made small. Furthermore, since moving the elastic force and are balanced position in the longitudinal direction of the driving force and the two spring of each lens produced depending on the current applied to the front coil and the rear coil, only the amount of current flowing through the respective coils, The amount of movement can be determined. As a result, the structure of the apparatus can be further reduced. Compared with the prior art shown in FIG. 5, since the motor 101, the gear 102, and the feed screw 103 are not used, the apparatus is small and light, and the positional accuracy is good because the gears and screws are not loose.
Since the front spring and the rear spring are structured to be extended and assembled, initial strain of the spring constant can be avoided.
[0007]
The invention according to claim 2 is characterized in that, in the invention according to claim 1, the front spring is used as a power supply path to the front coil, and the rear spring is used as a power supply path to the rear coil.
[0008]
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
1 is a cross-sectional view showing a lens driving device according to the present invention, FIG. 2 is a cross-sectional view showing a cross section of the lens driving device of FIG. 1 at 60 degrees, and FIG. 3 is an exploded view of the lens driving device of FIG. 4 is a perspective view, and FIG. 4 is a cross-sectional view showing the operation of the lens driving device of FIG.
[0010]
The lens driving device 1 includes a front lens 2, a front lens frame 31, a front support 3, a front coil 4, a front spring 5, a rear lens 6, a rear support 7, a rear coil 8, and a rear spring. 9, a magnet 10, a magnet support 21, and a yoke 11, the front coil 4 is wound around the outer gap between the magnet 10 and the yoke 11 in the circumferential direction, and the rear coil 8 is a magnet 10. and arranged wound inside the gap in the circumferential direction between the yoke 11, by applying a direct current to the front coil 4, to move by applying a forward driving force to the front lens 2, the DC current to the rear coil 8 by applying, it has become as to move the rear lens 6 by applying a forward driving force. In the present specification, the terms “front” and “rear” are used as appropriate. This indicates the positional relationship between the front and the rear relative to the subject from the camera.
[0011]
The ring-shaped D front support 3 is a molded product (electrical insulator) such as a synthetic resin, supports the front lens frame 31 at the top, includes the front coil 4 at the outer periphery rear, The outer end 5a of the front spring 5 is fixed, and projections 22 are provided at four positions every 90 degrees on the rear part of the inner periphery to act as a retaining member, and a rib 23 which is a small projection at the rear end. And sliding with the outer peripheral portion of the magnet support 21. The lead wire of the front coil 4 is soldered to the outer end portion 5a of the front spring 5 in the vicinity of the protrusion on the frontmost portion through the groove on the outer peripheral portion of the front support 3. The front lens frame 31 supports the front lens 2 at the inner peripheral portion.
[0012]
Similarly, the ring-shaped rear support 7 is a molded product (electrical insulator) such as a synthetic resin, supports the rear lens 6 at the center, and the rear coil 8 between the inner periphery and the arm 7a. The inner end portion 9b of the rear spring 9 is fixed to the protrusion on the bottom surface of the rear portion.
[0013]
The ring-shaped yoke 11 is a magnetic material such as soft iron and has a shape including an outer wall 11a, an inner wall 11b, and a bottom surface 11c. The outer wall 11a has a wall height larger than the inner wall 11b, and is spaced by 90 degrees from the inner wall 11b. The four cutouts 11d are provided, and the arm portion 7a of the rear support frame 7 passes through the cutout 11d.
[0014]
The magnet support 21 is a molded product (electrical insulator) made of synthetic resin, etc., and the upper and lower rings have a bowl shape supported by the four columns, and the four magnets 10 are fitted between the four columns. Is supported. For mass production, it is convenient to manufacture by integral molding. The magnet 10 is composed of four identical rectangular arc-shaped pieces, and is magnetized in the radial direction, and the bowl shape of the magnet support 21 ensures the rigidity of the structure that can counter the repulsive force of the magnet 10. .
[0015]
The magnet support 21 is fitted and fixed to the bottom portion 11c of the yoke 11 at the bottom, and the inner end portion 5b of the front spring 5 is fixed to the projection at the foremost portion, and the vertical groove 21a is formed at the inner peripheral portion near the projection. It has. A metal front terminal 32 is inserted into the vertical groove 21a, and is soldered to the inner end 5b of the front spring 5 at the foremost part, and the front / rear part penetrates the bottom surface 11c of the yoke 11. It acts as a power supply terminal to the front coil 4. A protrusion 21c is provided on the outer peripheral upper end of the peripheral portion, and acts as a retaining stopper that abuts against the protrusion 22 of the front support 3, and the side surface of the protrusion 21c is against the front spring 5 from a radial impact. It has a structure that mechanically suppresses the applied displacement. Elongated ribs are provided in the inner peripheral part (four places) of the peripheral part to facilitate sliding with the outer peripheral part of the rear support 7.
[0016]
The lead wire of the rear coil 8 penetrates the notch 11d along the side surface of the arm portion 7a and is soldered to the inner end portion 9b of the rear spring 9. The outer end portion 9a of the rear spring 9 is fixed to the protrusion at the bottom of the rearmost portion of the magnet support 21 and acts as a power supply terminal together with the spring retainer.
[0017]
The front coil 4 is disposed between the outer gap formed by the magnet 10 and the outer wall 11a. Similarly, the rear coil 8 is disposed between the inner gap formed by the magnet 10 and the inner wall 11b. A magnetic path returning to the magnet 10 via the bottom surface 11c and the inner wall 11b is formed.
[0018]
The front spring 5 and the rear spring 9 are metallic leaf springs such as phosphor bronze, have a spring property, and also act as a power feeding path to the front coil 4 and the rear coil 8. The outer end 5a of the front spring 5 is screwed into the protrusion of the front support 3 and pressed and fixed (heat caulking) with the spring retainer 5aa, and the inner end 5b is screwed into the protrusion of the magnet support 21 and springed. It is pressed and fixed with the presser 5bb. When the front support 3 is inserted into the yoke 11, the flange portion 3a of the front support 3 abuts against the upper surface portion of the outer wall 11a of the yoke 11, so that a step is generated between the outer end 5a and the inner end 5b. The front spring 5 is extended and assembled. The spring retainer 5bb has a shape protruding in the inner peripheral direction, and also plays a role of preventing the rear support 7 from coming off.
Each of the front spring 5 and the rear spring 9 has a substantially semicircular inner peripheral side portion and an outer peripheral side portion, and the inner peripheral side portion and the outer peripheral side portion are connected at one end in the circumferential direction. Two leaf springs having an inner end portion which is the other end in the circumferential direction of the portion and an outer end portion which is the other end in the circumferential direction of the outer peripheral side portion are combined into a substantially ring shape.
[0019]
The outer end 9a of the rear spring 9 is inserted into the protrusion of the magnet support 21 and is fixed by pressing with the spring retainer 9aa, and the inner end 9b is inserted into the protrusion of the rear support 7 with the spring retainer 9bb. Hold down and fix. When the rear support 7 is inserted into the yoke 11, the protrusions 7b (four locations) of the rear support 7 abut against the bottom surface 11c of the yoke 11, thereby creating a step between the outer end 9a and the inner end 9b. The rear spring 9 is also extended and assembled. Thus, since the front spring 5 and the rear spring 9 are stretched and assembled even when they are housed in the rearmost direction, it is possible to avoid initial distortion of the spring constant inherent to the leaf spring.
[0020]
Next, the operation of the present embodiment will be described based on the configuration described above. To assemble the lens driving device 1, first, the front coil 4 is assembled into the front support 3, the rear lens 6 and the rear coil 8 are assembled into the rear support 7, and each is fixed. The lead wire of the front coil 4 is fixed in advance along two outer peripheral recesses of the front support 3 and pulled out in advance. Further, the magnet 10 is incorporated in the magnet support 21.
[0021]
Next, the rear support 7 is assembled into the magnet support 21, the rear spring 9 and the spring retainers 9aa and 9bb are attached, and then the front support 3 and the front terminal 32 are assembled into the magnet support 21, the front spring 5 and the spring. The pressers 5aa and 5bb are attached. The lead wire of the rear coil 8 and the lead wire of the front coil 4 are connected by soldering to the inner end portion 9b and the outer end portion 5a, respectively, and the front terminal 32 is also connected by soldering.
[0022]
Subsequently, the yoke 11 is assembled into the magnet support 21 and fixed (press-fit) at the bottom surface 11c. The front lens 2 is incorporated in the front lens frame 31 in advance, and the front lens frame 31 is fixed to the forefront portion of the magnet support 21.
[0023]
As a result of the assembly connection described above, two external inputs to the front coil 4 are obtained as two front terminals 32 in the through-hole portion of the bottom surface 11c of the yoke 11, and the two external inputs to the rear coil 8 are It is obtained as two outer end portions 9 a of the rear spring 9.
[0024]
FIG. 4 shows a cross-sectional view when a DC current is applied to the front coil 4 and the rear coil 8 to operate the lens driving device 1 in the zoom state.
[0025]
When a current is applied to the front coil 4, an electromagnetic force forward (upward in FIG. 4) acts on the front lens 2, but the elastic force of the front spring 5 is rearward (downward in FIG. 4) in proportion to the displacement. ) Work. Therefore, the position of the front lens 2, that is, the moving distance forward is a point where the electromagnetic force and the elastic force are balanced.
[0026]
Thereby, the amount of movement of the front lens 2 can be determined by the amount of current applied to the front coil 4. Similarly, the amount of movement of the rear lens 6 can be determined by the amount of current applied to the rear coil 8.
[0027]
That is, the amount of movement of each of the front lens 2 and the rear lens 6 can be determined by the respective current amounts applied to the front coil 4 and the rear coil 8, so that the rear lens 6 is further rearward (downward in FIG. 4). In addition to the action of a fixed lens located inside the camera, the subject image can be zoomed and focused on an image plane such as a CCD.
[0028]
The rear support 7 is provided with a rear coil 8 between the inner peripheral portion and the arm portion 7a, and two lead wires of the rear coil 8 pass through the notch 11d along the side surface of the arm portion 7a. Since the structure is connected to the inner end 9bb of the rear spring 9, the rear support 7 can be disposed inside the magnet, and a small structure is realized.
[0029]
The front support 3 includes ribs 23 that are extremely small protrusions at four positions at 90 ° intervals at the rearmost portion of the protrusions 22 and slides on the outer periphery of the magnet support 21. Since the four ribs 23 are opposed to each other, they can be molded with high precision and have a small sliding area, so that the front lens 2 can be moved smoothly and with less blur.
[0030]
The magnet support 21 is provided with a protrusion 21c at the outer peripheral upper end, and acts as a retaining stopper that abuts against the protrusion 22 of the front support frame 3 to prevent the front support 3 from falling off. The spring 5 has a structure that mechanically suppresses the displacement applied from the radial impact.
[0031]
Further, since the magnet support 21 has a hook shape in which the upper and lower rings are supported by the four support columns, a firm structure is realized against the repulsive force of the magnet 10.
[0032]
Furthermore, since the front spring 5 and the rear spring 9 are extended and assembled even when they are housed in the rearmost position, initial strain of the spring constant can be avoided.
[0033]
【The invention's effect】
In the first aspect of the invention, the rear lens can be disposed inside the magnet, and the amount of movement of each of the front lens and the rear lens can be controlled by controlling the amount of current applied. The structure can be made small and inexpensive, and the strength can be improved.
[0034]
According to the second aspect of the invention, the same effects as those of the first aspect of the invention can be achieved, and the distortion of the spring constant can be suppressed to improve the accuracy of the positions of the front lens and the rear lens.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a lens driving device according to the present invention.
FIG. 2 is a cross-sectional view showing a cross section of the lens driving device of FIG.
3 is an exploded perspective view of the lens driving device of FIG. 1. FIG.
4 is a cross-sectional view showing the operation of the lens driving device of FIG. 1. FIG.
FIG. 5 is a perspective view showing a conventional lens driving device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Lens drive device 2 Front lens 3 Front support body 4 Front coil 5 Front spring 6 Rear lens 7 Back support body 8 Back coil 9 Back spring 10 Magnet 11 Yoke 21 Magnet support body 31 Front lens frame

Claims

A front lens, a front lens frame that supports the front lens, a front support that supports the front lens frame, a front coil that is attached to the front support, a front spring that is attached to the front support, a rear lens, and a rear A rear wall that supports the lens, a rear coil that is attached to the rear support, a rear spring that is attached to the rear support, a magnet, a magnet support, an inner wall, and an outer wall are formed in a cylindrical shape to form a bottom wall The magnet support is provided between the inner wall and the outer wall of the yoke, and the magnet is arranged with a gap between each wall, and the magnet is magnetized in the radial direction. There, the front coil is arranged by winding the outer gap in the circumferential direction between the magnet and the yoke outer wall, the rear coil, the inner gap between the magnet and the yoke inner wall Circumferentially winding arranged to impart longitudinal direction of the driving force to the front lens by applying a current to the forward coil, it is moved to a position where balance the front lens and the elastic force of the front spring, the rear coil A lens driving device that applies a driving force in the front-rear direction to the rear lens by applying an electric current, and moves the rear lens to a position that balances the elastic force of the rear spring,
Each of the front spring and the rear spring has a substantially semicircular inner peripheral side portion and an outer peripheral side portion, and the inner peripheral side portion and the outer peripheral side portion are connected at one end in the circumferential direction. Two leaf springs having an inner end portion which is the other end in the circumferential direction and an outer end portion which is the other end in the circumferential direction on the outer peripheral side portion are combined into a substantially ring shape. It is flat and assembled in a state where it is stretched and elastically deformed to create a step between the inner end and the outer end during assembly. The outer end of the front spring is fixed to the front end of the front support. The lens is characterized in that the portion is fixed to the front end of the magnet support, the rear spring has an inner end fixed to the rear end of the magnet support, and an outer end fixed to the rear end of the rear support. Drive device.

2. The lens driving device according to claim 1, wherein the front spring is used as a power supply path to the front coil, and the rear spring is used as a power supply path to the rear coil.