201007322 六、發明說明： 【發明所屬之技術領域】 本發明係關於搭載於附照相機之行動電話等之小型透鏡 驅動裝置。 【先前技術】 近年來作為搭載於附照相機之行動電話等之透鏡驅動 裝置’期望擴大透鏡之安裝空間。先前，作為紅該要求 之透鏡驅動裝置，已知有將㈣⑽架之磁性電路設於透 鏡架之四方者（例如，參照專利文獻1)。該透鏡驅動裝置藉 由於透鏡架之四方設磁性電路，較之跨透鏡架之全周設磁 性電路之情形，其透鏡之安裝空間變大。 該專利文獻1所記載之透鏡驅動裝置具備：安裝透鏡之 透鏡架；以平面視形成為矩形狀之基座；及形成環狀之耗 架’且’係以包圍透鏡架之方式將軛架安裝於基座而構 成。輛架係以具有外周壁部與内周壁部之剖面u字形形 成’且於姉之外龍部與内周壁部之間置有圓筒狀的空 怒線圏，其以包圍透鏡架之方式設置。又，空芯線圈之外 侧及耗架之外周壁部之内側，以對應基座之四角之方式設 有4個具有圓弧狀磁極面的磁石。且，透鏡驅動裝置藉由 輛架與4個圓弧狀磁石形成磁性電路，而藉由於空芯線圈 通電產生之電磁力使透鏡架於光軸方向上移動。 又’先前’作為於透鏡架之四方設置磁性電路者，已知 有於以八角形之筒狀形成之外罩之相對面設置磁性電洛者 (例如，參照專散獻2)。該專利文獻2所記載之透鏡驅動 141246.doc 201007322 裝置具備：安裝透鏡之透鏡架··；以平面視其形成為矩形狀 之基座；及以八角形之筒狀形成之金屬製外罩；且，係以 包圍透鏡架之方式將外罩安裝於基座而構成。於透鏡架之 周圍配置有八角形之空芯線圈’而於八角形之外罩之相對 面設有4個平板狀之磁石。且，透鏡驅動裝置藉由筒狀之 外罩與4個板狀磁石形成磁性電路，而藉由於空芯線圈通 電產生之電磁力使透鏡架於光軸方向上移動。 [專利文獻1]曰本特開2007-1398 10號公報 [專利文獻2]曰本實用新案登錄第3 132165號公報 【發明内容】 [發明所欲解決之問題] 然而，專利文獻1所記載之透鏡驅動裝置，由於使用了 具有平行於圓筒狀線圏之外周面的磁極面的圓弧狀磁石， 因此使磁石之加工變得困難，有生產成本增加之問題。 又’專利文獻2所記載之透鏡驅動裝置，由於金屬製外 罩未以將磁石產生之磁束導入線圏之方式彎曲形成，因此 由磁石朝向線圈之磁束量較少，未能賦與透鏡架充分的驅 動力。 本發明係鑒於上述問題點而完成者，其目的在於提供一 種可擴大透鏡之安裝空間的同時，兼可降低生產成本，且 可獲得充分之驅動力的透鏡驅動裝置。 [解決問題之技術手段] 本發明之透鏡驅動裝置，其特徵為具備：保持透鏡之透 鏡架；及使上述透鏡架於光轴方向上移動之透鏡驅動部； 141246.doc 201007322 且，上述透鏡驅動部具有：八角形之空芯線圈，其配置於 上述透鏡架之周圍；軛架，其包含具有八角形内周面的外 壁。卩、及與上述外壁部隔著間隔而相對之内壁部，且以使 上述空芯線圈位於上述外壁部與上述内壁部之間之方式覆 蓋上述空芯線圈；及平板狀磁石，其設於上述軛架之外壁 部之相對之四面；再者，上述軛架之内壁部之一部分與上 述磁石之磁極面相對，且成平行。 根據該構成，由於軛架之外壁部具有八角形之内周面， 且該外壁部相對之四面設有磁石，因此，較之於透鏡架之 四方形成磁性電路、與跨透鏡架之全周形成磁性電路之情 形，可擴大透鏡之安裝空間。 又，由於使用加工容易之平板狀之磁石，故可降低生產 成本。 再者’由於内壁部之一部分與磁石之磁極面相對，且成[Technical Field] The present invention relates to a small lens driving device mounted on a mobile phone with a camera or the like. [Prior Art] In recent years, it has been desired to enlarge the mounting space of the lens as a lens driving device mounted on a mobile phone with a camera. In the prior art, it is known that the magnetic circuit of the (4) (10) frame is provided in the lens holder (see, for example, Patent Document 1). Since the lens driving device is provided with a magnetic circuit in all directions of the lens holder, the mounting space of the lens becomes larger as compared with the case where the magnetic circuit is provided over the entire circumference of the lens holder. The lens driving device described in Patent Document 1 includes a lens holder to which a lens is attached, a pedestal formed in a rectangular shape in plan view, and a ring-shaped rack "and" for mounting the yoke so as to surround the lens holder Constructed on the base. The frame is formed in a U-shape having a cross section of the outer peripheral wall portion and the inner peripheral wall portion, and a cylindrical hollow line 置 is disposed between the dragon portion and the inner peripheral wall portion outside the cymbal, and is disposed to surround the lens holder. . Further, on the outer side of the air-core coil and the inner side of the outer peripheral wall portion of the consumable frame, four magnets having arc-shaped magnetic pole faces are provided so as to correspond to the four corners of the base. Further, the lens driving device forms a magnetic circuit by the frame and the four arc-shaped magnets, and the lens holder moves in the optical axis direction by the electromagnetic force generated by the energization of the air core coil. Further, it is known that a magnetic circuit is provided on the four sides of the lens holder, and it is known to provide a magnetic shovel on the opposite surface of the outer cover formed in an octagonal shape (for example, refer to the exclusive scatter 2). The lens drive 141246.doc 201007322 described in Patent Document 2 includes a lens holder on which a lens is attached, a pedestal formed in a rectangular shape in plan view, and a metal cover formed in an octagonal cylindrical shape; The outer cover is attached to the base so as to surround the lens holder. An octagonal hollow core coil is disposed around the lens holder, and four flat magnets are disposed on the opposite side of the octagonal outer cover. Further, the lens driving device forms a magnetic circuit by the cylindrical cover and the four plate-shaped magnets, and the lens holder moves in the optical axis direction by the electromagnetic force generated by the energization of the air-core coil. [Patent Document 1] Japanese Unexamined Patent Application Publication No. Publication No. Publication No. Publication No. No. No. No. No. No. No. No. No. No. No. In the lens driving device, since an arc-shaped magnet having a magnetic pole surface parallel to the circumferential surface of the cylindrical coil is used, processing of the magnet becomes difficult, and there is a problem that the production cost increases. Further, in the lens driving device described in Patent Document 2, since the metal cover is not bent so as to introduce the magnetic flux generated by the magnet into the wire, the amount of magnetic flux from the magnet toward the coil is small, and the lens holder is not sufficiently provided. Driving force. The present invention has been made in view of the above problems, and an object thereof is to provide a lens driving device which can enlarge a mounting space of a lens and at the same time reduce production cost and obtain sufficient driving force. [Means for Solving the Problems] The lens driving device of the present invention includes: a lens holder that holds a lens; and a lens driving unit that moves the lens holder in the optical axis direction; 141246.doc 201007322 The portion has an octagonal hollow core coil disposed around the lens holder, and a yoke including an outer wall having an octagonal inner peripheral surface. And an inner wall portion that faces the outer wall portion with a gap therebetween, and covers the hollow core coil so that the air core coil is located between the outer wall portion and the inner wall portion; and the flat magnet is provided on the The opposite sides of the outer wall portion of the yoke; further, a portion of the inner wall portion of the yoke is opposed to the magnetic pole surface of the magnet and is parallel. According to this configuration, since the outer wall portion of the yoke has an octagonal inner peripheral surface, and the outer wall portion is provided with magnets on opposite sides, the magnetic circuit is formed in all directions of the lens holder, and the entire circumference of the lens holder is formed. In the case of a magnetic circuit, the installation space of the lens can be enlarged. Further, since the flat magnet is easily processed, the production cost can be reduced. Furthermore, since one part of the inner wall portion is opposite to the magnetic pole surface of the magnet,
平行地形成轭架，因此由磁石朝向空芯線圈之磁束量增 多，可獲得充分之驅動力。 曰 又’本發明之上述透鏡驅動裝置之特徵為，其中上述軛 架僅於相對於上述心之磁極面之部分具有上述内壁部， 且，上述内壁部係藉由切割而形成。 根據該構成，由於内壁部将益+ — 立丨係藉由切割而形成，因此，較 之藉由深衝而形成之情形，其 刀工工數減少，可降低生產 成本。 之特徵為’其中上述軛 又，本發明之上述透鏡驅動裝置 架之相鄰内壁部之間形成有缺口部 141246.doc 201007322 壁部之間形成有缺口 根據該構成，由於軛架之相鄰内 部，因此可順利進行切割。 又，本發明之上述透鏡驅動裝置之特徵為，其中於上述 透鏡架之外周面形成有突狀部；上述缺口部係以容許形成 有上述突狀部之上述透鏡架之光轴 疋和万向的移動而形成。 根據該構成’即使於透鏡架 <y卜周面设有突狀部，亦可 使透鏡架於光軸方向上移動。Since the yoke is formed in parallel, the amount of magnetic flux from the magnet toward the air-core coil is increased, and a sufficient driving force can be obtained. Further, the lens driving device according to the invention is characterized in that the yoke has the inner wall portion only at a portion facing the magnetic pole surface of the core, and the inner wall portion is formed by cutting. According to this configuration, since the inner wall portion is formed by cutting, the number of cutters is reduced as compared with the case of deep drawing, and the production cost can be reduced. The feature is that the yoke and the adjacent inner wall portion of the lens driving device frame of the present invention are formed with a notch portion 141246. doc 201007322. A gap is formed between the wall portions according to the configuration, due to the adjacent interior of the yoke Therefore, the cutting can be carried out smoothly. Further, in the lens driving device of the present invention, the peripheral surface of the lens holder is formed with a projecting portion, and the notch portion is configured to allow the optical axis and the universal direction of the lens holder in which the protruding portion is formed. The movement is formed. According to this configuration, even if a projection portion is provided on the peripheral surface of the lens holder <y, the lens holder can be moved in the optical axis direction.
又’本發明之上述透鏡驅動裝置之特徵為，其中上述突 狀部係用以由内側支撐上述空芯線圈之線圈支撑部。 根據該構成，即使於透鏡架之外周面設有線圈支撲部， 亦可使透鏡架於光軸方向上移動。 [發明之效果] 根據本發明，可擴大透鏡之安裝空間的同時，兼可降低 生產成本，且可獲得充分之驅動力。 【實施方式】Further, in the above lens driving device of the present invention, the protruding portion is configured to support the coil supporting portion of the hollow core coil from the inner side. According to this configuration, even if the coil support portion is provided on the outer peripheral surface of the lens holder, the lens holder can be moved in the optical axis direction. [Effects of the Invention] According to the present invention, it is possible to enlarge the installation space of the lens, and at the same time, it is possible to reduce the production cost and obtain a sufficient driving force. [Embodiment]
以下，茲參照附加圖式詳細說明本發明之實施形態。圖 1係本發明之實施形態之透鏡驅動裝置的整體立禮圖。圖2 係本發明之實施形態之透鏡驅動裝置的分解立體圖。 如圖1及圖2所示’透鏡驅動裝置1上安裝有未圖示之透 鏡，且该透鏡驅動裝置係被安裝於裝有未圖示之圖像感測 器之基板上，相對於圖像感測器使透鏡於光轴方向上驅 動’而調整焦點距離者’且其構成安裝有：下機殼U，其 安裝内板12及下板彈簧13;透鏡架14，其載置於下機殼11 上，空芯線圈15，其固定於透鏡架14;耗架π，其覆蓋空 141246.doc 201007322 芯線圈15並於内部配設磁石16;及頂罩19，其安裝上板彈 簧18。 下機殼11係由矩形之板狀構件構成，且中央形成有圓形 開口 21。於下機殼11之四角分別形成有朝上方突出之—對 突出部22a、22b，而藉由該一對突出部22a、22b於前後左 右定位軛架Π、内板12、及下板彈簧13。又，於四角分別 形成之突_出部22a、22b中’爽開口 21而相對之一組突出部 22a、22b之間分別形成有朝上方突出之扣合栓23，而另一 組突出部22a、22b之間分別設有連接空芯線圈15之端部之 端子部24。又’於下機殼11之開口 21之周緣形成有階梯部 25 ° 内板12，係由中央具有直徑大於下機殼丨丨之開口 21之開 口 31的環狀部34、及由該環狀部3 4之四方朝控向外側突出 之突出片32a、32b構成。夾著内板12之開口 31而相對之突 出片係以同一形狀形成’且突出片32a上形成有扣合於下 機殼11之扣合栓23之扣合孔33，而突出片32b係以窄幅形 成’以避開下機殼11之端子部24。内板12係藉由將突出片 32a之扣合孔33扣合於扣合栓23，且將各突出片32a、32b 分別扣合於各突出部22a、22b，而前後左右被載置定饭於 下機殼11。 下板彈簧13係由中央具有直徑大致相同於内板12之開口 31之開口 35的彈簧部38、及由該彈簀部38之四方朝徑句外 側突出之突出片36a、36b構成。夾著下板彈簧13之開口 35 而相對之突出片係以同一形狀形成，且突出片36a上形成 141246.doc 201007322 有扣合於下機殼11之扣合栓23之扣合孔37，而突出片36b 係以窄幅形成，以避開下機殼11之端子部24。下板彈菁！ 3 係藉由將突出片36a之扣合孔37扣合於扣合栓23，且將各 突出片36a、36b分別扣合於各突出部22a、22b，而前後左 右被定位於下機殼11並配置於内板12上。 透鏡架14係由具有大致八角形之外周面的筒部41、由筒 部4 1之外周面朝徑向外側突出之鍔部42、及筒部41之下部 被部分切割而形成之3個圓弧狀的扣合突部43構成。於筒 部4 1之内周面形成有母螺紋部44，該母螺紋部44安裝有具 備未圖示之透鏡之透鏡單元。又，筒部41之外周面突出形 成有線圈支樓部45，其由内側支撐空芯線圈15。 鍔部42之上面成為固定空芯線圈15之底面的固定面，且 空芯線圈15，由於底面固定於鳄部42之上面，同時内周面 由線圈支撐部45部分支撐，因此空芯線圈15之申心軸與透 鏡架14之中心軸被以一致之狀態保持。3個扣合突部43將 下板彈簧1 3之開口 3 5及内板12之開口 3 1插通，而分別扣合 於下機设11之階梯部25。透鏡架14，藉由3個扣合突部43 扣合於階梯部25 ’而以鳄部42之下面藉由下板彈篑13向上 方賦與勢能之狀態被載置於下機殼11上。 空心線圈15係將導線以八角形之筒狀捲繞而形成，且以 藉由線圈支樓部4 5由内側支樓之狀態，以包圍筒部41之周 圍之方式固定於鳄部42之上面。此時，空芯線圈15與筒部 41之間形成有介有軛架17之内壁部56(參照圖3)之程度的間 隙。又’空芯線圈15較之線圈支撐部45於光軸方向形成較 141246.doc 201007322 短，在空芯線圈15固定於透鏡架Μ之狀態下，線圈支撐部 45之上部稍露出於空芯線圈15之上方。又，空芯線圈15之 一對端部被分別連接於下機殼11之端子部24。 軛架17係以八角形之環狀形成，且軛架17内對應下機殼 11之四角配設有磁石16 〇軛架17係以覆蓋空芯線圈15之方 式以定位狀態安裝於下機殼11，於軛架17之中央之開口部 分置有透鏡架14之筒部41。且，由軛架17與磁石16形成磁 性電路，驅動固定有空芯線圈15之透鏡架14。另，軛架17 與磁石16之詳細說明如後述。又，請求項之透鏡驅動部係 由本實施形態之軛架17、磁石16、及空芯線圈15構成。 上板彈簧18係由具有直徑小於軛架17之開口部分的開口 47且以環狀形成之支撐部48、及形成於支撐部48之内惻之 彈簧部49構成。上板彈簧18載置於軛架17之上面，彈簧部 49抵接於透鏡架14之筒部41的上面。頂罩19係由中央具有 圓形開口 51之矩形之板狀部52、及由板狀部52之四角朝下 方延伸之4個腳部5 3形成，且係藉由經由上板彈簧18霞蓋 軛架17而安裝。如此，藉由由下順序安裝下機殼η、内板 12、下板彈簧13、透鏡架14、空芯線圈15、軛架17'上板 彈簧18、及頂罩19，將各構件配置於同軸上。 此處，參照圖3詳細說明軛架及磁石之構成。圖3係以水 平面切斷圖1之透鏡驅動裝置的橫剖面圖。 如圖3所示，軛架17之構成具有：以八角形形成之外周 壁部55 ;及對於外周壁部55之四角以間隔相對之4個内壁 部56。該4個内壁部56係藉由切割而形成，且鄰接之内壁 141246.doc 201007322 部56間形成有缺口部57。該缺口部57於十刀割内壁部％時形 成，藉由於鄰接之内壁部56間形成缺口部57，可順利進行 切割。如此，各内壁部56由於係藉由切割形成，因此可減 少加工工數而降低生產成本。 又，缺口部57置有形成於透鏡架14之外周面之線圈支撐 部45，根據該構成，即使於透鏡架14之側面設置線圈支撐 部45等之突狀部之情形，亦容許透鏡架“之光轴方向之驅 動。又，各内壁部56係以平行於外周壁部55而形成。 外周壁部55之八角形之内周面之四角固定有平板狀之磁 石16，且各磁石16之磁極面平行於内壁部56之壁面。又， 外周壁部55與内壁部56之間收納有空芯線圈15，而於軛架 17之四角，在磁石16與内壁部56之間配置有空芯線圈15。 其後’參照圖4說明透鏡架之驅動動作。圖4係將圖1之 透鏡驅動裝置以沿對角線之平面切斷的縱刮面圖。 如圖4所示，透鏡驅動裝置1中，由於軛架17之外周壁部 55之四角固定有磁石16’且相對於磁石16之磁極面置有内 壁部56，因此於透鏡驅動裝置1之四角形成有磁性電路。 該磁性電路係磁石16之磁極面產生之磁束通過空芯線圈15 朝向内壁部56而形成’當在該狀態下將空芯線圈15通電 時’空芯線圈15之光軸方向將產生電磁力。 然後’透鏡架14抵抗上板彈簧18及下板彈簧13之賦能 力’藉由空芯線圈15產生之電磁力於光軸方向上移動，調 整未圖示之透鏡與圖像感測器之焦點距離。該情形，由於 軛架17之内壁部56與磁石16之磁極面係平行，因此通過空 141246.doc •10· 201007322 怒線圈15之磁束量多，即使僅於透鏡驅動裝置1之四角形 成磁性電路，亦可產生充分之驅動力。 如上所述，根據本實施形態之透鏡驅動裝置1，由於輛 架17之外周壁部55具有八角形之内周面，且該外周壁部55 之相對之四面設有磁石16，因此於透鏡架14之四方形成磁 性電路’較之跨透鏡架1 4之全周形成磁性電路之情形，可 擴大透鏡之安裝空間。 又’由於可擴大透鏡之安裝空間，因此可以圓柱形狀形 成透鏡架14之筒部41，可於安裝透鏡驅動裝置1後安裝透 鏡單元。 又’由於使用了加工容易之平板狀磁石16，因此可降低 生產成本。 再者’由於以内壁部56與磁石16之磁極面相對且平行之 方式形成軛架17’因此由磁石16朝向空芯線圈15之磁東量 多，可獲得充分之驅動力。 另，本實施形態之構成係於鄰接之内壁部56間形成缺口 部57後切割内壁部56，然而亦可係於鄰接之内壁部56間代 替缺口部57而形成切口後切割内壁部56之構成。該情形， 於透鏡架14之筒部41之外周面將不形成線圈支撐部45等之 突狀部。 又，本實施形態之構成係使内壁部56之壁面平行於磁石 16之磁極面，然而亦可係使内壁部5 6之壁面稍傾斜於磁石 16之磁極面的構成。該情形下’藉由使用磁力強的磁石而 獲得透鏡架14之驅動力。 141246.doc 11 201007322 又，本次揭示之實施形態之所有要點僅為例示，本發明 並非限定於該實施形態。本發明之範圍並非僅為上述實施 开> 態之說明，其根據申請專利之範圍所示，包含與申請專 利之範圍均等之意義及範圍内所有更改之内容。 [產業上之可利用性] 如上說明，本發明具有可擴大透鏡之安裝空間之同時， 亦可降低生產成本、且獲得充分之驅動力的效果尤其有 用於附照相機之行動電話等所搭載之小型透鏡驅動裝置。 【圖式簡單說明】 圖1係顯示本發明之透鏡驅動裝置之實施形態的圖其 係透鏡驅動裝置之整體立體圖； 圖2係顯示本發明之透鏡驅動裝置之實施形態的圖其 係透鏡驅動裝置之分解立體圖； 圖3係顯示本發明之透鏡驅動裝置之實施形態的圖，其 係以水平面切斷圖丨之透鏡驅動裝置的橫剖面圖；及 圖4係顯示本發明之透鏡驅動裝置之實施形態的圖，其 係將圖1之透鏡驅動裝置以沿對角線之平面切斷的縱剖面 φ 圖。 【主要元件符號說明】 1 透鏡驅動裴置 11 下機殼 12 内板 14 透鏡架 15 空芯線圈（透鏡驅動部） 141246.doc 201007322 16 17 19 45 55 56 57 磁石（透鏡驅動部） 軛架（透鏡驅動部） 頂罩 線圈支撐部 外周壁部（外壁部） 内壁部 缺口部 141246.doc -13-Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Fig. 1 is a perspective view of the entire lens driving device according to an embodiment of the present invention. Fig. 2 is an exploded perspective view of the lens driving device according to the embodiment of the present invention. As shown in FIGS. 1 and 2, a lens (not shown) is attached to the lens driving device 1, and the lens driving device is mounted on a substrate on which an image sensor (not shown) is mounted, with respect to the image. The sensor drives the lens in the optical axis direction to adjust the focus distance' and is configured to be mounted with a lower casing U that mounts the inner panel 12 and the lower plate spring 13; the lens holder 14 is placed on the lower machine On the casing 11, an air-core coil 15 is fixed to the lens holder 14; it consumes π, which covers the core 141246.doc 201007322 core coil 15 and is internally provided with a magnet 16; and a top cover 19 to which the upper leaf spring 18 is mounted. The lower casing 11 is constituted by a rectangular plate-like member, and a circular opening 21 is formed in the center. The four corners of the lower casing 11 are respectively formed with the protruding portions 22a and 22b protruding upward, and the yoke frame, the inner plate 12, and the lower plate spring 13 are positioned by the pair of protruding portions 22a and 22b. . Further, in the protruding-out portions 22a and 22b formed at the four corners, a cool opening 21 is formed, and a pair of protruding portions 22a and 22b are respectively formed with a locking bolt 23 protruding upward, and the other group of protruding portions 22a. Terminal portions 24 that connect the ends of the air-core coils 15 are provided between 22b and 22b. Further, a step portion 25° inner plate 12 is formed on the periphery of the opening 21 of the lower casing 11, and an annular portion 34 having an opening 31 having a diameter larger than the opening 21 of the lower casing 、 is formed, and the ring is formed by the ring The four portions of the portion 34 are formed by the projecting pieces 32a and 32b which protrude outward. The protruding piece 31 of the inner panel 12 is opposed to the protruding piece formed in the same shape, and the protruding piece 32a is formed with a fastening hole 33 fastened to the fastening bolt 23 of the lower casing 11, and the protruding piece 32b is A narrow width is formed 'to avoid the terminal portion 24 of the lower casing 11. The inner panel 12 is fastened to the respective engaging portions 22a and 22b by engaging the engaging holes 33 of the protruding piece 32a with the engaging holes 33, and the protruding pieces 32a and 32b are respectively engaged with the protruding portions 22a and 22b. In the lower case 11. The lower plate spring 13 is composed of a spring portion 38 having a center having a diameter substantially the same as the opening 35 of the opening 31 of the inner panel 12, and projecting pieces 36a and 36b projecting outward from the outer side of the elastic portion 38. The protruding piece 35 of the lower plate spring 13 is formed to be formed in the same shape, and the protruding piece 36a is formed with a fastening hole 37 which is fastened to the fastening bolt 23 of the lower casing 11 by the 141246.doc 201007322. The protruding piece 36b is formed in a narrow width to avoid the terminal portion 24 of the lower casing 11. The next board is playing! 3, the fastening holes 37 of the protruding piece 36a are fastened to the fastening bolts 23, and the protruding pieces 36a, 36b are respectively fastened to the respective protruding portions 22a, 22b, and are positioned to the lower casing 11 in front, rear, left and right. And disposed on the inner panel 12. The lens holder 14 is composed of a cylindrical portion 41 having a substantially octagonal outer peripheral surface, a crotch portion 42 projecting radially outward from the outer peripheral surface of the tubular portion 41, and three circles formed by partial cutting of the lower portion of the tubular portion 41. The arcuate fastening projection 43 is formed. A female screw portion 44 is formed on the inner circumferential surface of the tubular portion 41, and a lens unit having a lens (not shown) is attached to the female screw portion 44. Further, the outer peripheral surface of the tubular portion 41 is formed with a coil branch portion 45 which supports the hollow core coil 15 from the inner side. The upper surface of the crotch portion 42 serves as a fixing surface for fixing the bottom surface of the air-core coil 15, and the air-core coil 15 is fixed to the upper surface of the crocodile portion 42 while the inner peripheral surface is partially supported by the coil supporting portion 45, so that the air core coil 15 is provided. The center axis of the application spindle and the lens holder 14 are held in a consistent state. The three engaging projections 43 are inserted into the opening 35 of the lower plate spring 13 and the opening 3 1 of the inner plate 12, and are respectively engaged with the step portion 25 of the lower machine 11. The lens holder 14 is attached to the lower casing 11 by the three fastening projections 43 being engaged with the stepped portion 25' and with the lower surface of the crocodile portion 42 being biased upward by the lower plate magazine 13 . The air-core coil 15 is formed by winding a wire in an octagonal cylindrical shape, and is fixed to the upper surface of the crocodile portion 42 so as to surround the circumference of the tubular portion 41 by the state of the inner side branch of the coil branch portion 45. . At this time, a gap is formed between the air-core coil 15 and the tubular portion 41 to the extent that the inner wall portion 56 (see Fig. 3) of the yoke 17 is interposed. Further, the air core coil 15 is shorter than the coil support portion 45 in the optical axis direction by 141246.doc 201007322, and the upper portion of the coil support portion 45 is slightly exposed to the air core coil in a state where the air core coil 15 is fixed to the lens frame Μ. Above the 15th. Further, a pair of end portions of the air-core coil 15 are respectively connected to the terminal portions 24 of the lower casing 11. The yoke 17 is formed in an octagonal ring shape, and the yoke 17 is disposed at the four corners of the lower casing 11 with a magnet 16 yoke 17 to cover the hollow core coil 15 to be mounted in the lower casing in a positioning state. 11. A cylindrical portion 41 of the lens holder 14 is placed at an opening portion in the center of the yoke 17. Further, a magnetic circuit is formed by the yoke 17 and the magnet 16, and the lens holder 14 to which the hollow core coil 15 is fixed is driven. The detailed description of the yoke 17 and the magnet 16 will be described later. Further, the lens driving unit of the request item is composed of the yoke 17 of the present embodiment, the magnet 16, and the air core coil 15. The upper plate spring 18 is composed of a support portion 48 having an opening 47 having a diameter smaller than the opening portion of the yoke 17, and being formed in an annular shape, and a spring portion 49 formed in the inner portion of the support portion 48. The upper plate spring 18 is placed on the upper surface of the yoke 17, and the spring portion 49 abuts against the upper surface of the cylindrical portion 41 of the lens holder 14. The top cover 19 is formed by a rectangular plate-like portion 52 having a circular opening 51 at the center, and four leg portions 53 extending downward from the four corners of the plate-like portion 52, and is covered by the upper plate spring 18 The yoke 17 is mounted. In this manner, the lower casing η, the inner plate 12, the lower plate spring 13, the lens holder 14, the air core coil 15, the yoke 17' upper leaf spring 18, and the top cover 19 are mounted in the following order, and the respective members are disposed. On the coaxial. Here, the configuration of the yoke and the magnet will be described in detail with reference to Fig. 3 . Fig. 3 is a cross-sectional view showing the lens driving device of Fig. 1 cut horizontally. As shown in Fig. 3, the yoke 17 has a peripheral wall portion 55 formed in an octagonal shape and four inner wall portions 56 opposed to each other at four corners of the outer peripheral wall portion 55. The four inner wall portions 56 are formed by cutting, and a notch portion 57 is formed between the adjacent inner wall 141246.doc 201007322 portion 56. The notch portion 57 is formed when the inner wall portion is cut by ten, and the notch portion 57 is formed between the adjacent inner wall portions 56, so that the cutting can be smoothly performed. Thus, since each of the inner wall portions 56 is formed by cutting, the number of processing can be reduced and the production cost can be reduced. Further, the notch portion 57 is provided with a coil supporting portion 45 formed on the outer circumferential surface of the lens holder 14, and according to this configuration, even if a protruding portion such as the coil supporting portion 45 is provided on the side surface of the lens holder 14, the lens holder is allowed. Further, each of the inner wall portions 56 is formed in parallel with the outer peripheral wall portion 55. The flat-shaped magnets 16 are fixed at the four corners of the inner peripheral surface of the octagonal outer peripheral wall portion 55, and the magnets 16 are The magnetic pole surface is parallel to the wall surface of the inner wall portion 56. Further, the air core coil 15 is accommodated between the outer peripheral wall portion 55 and the inner wall portion 56, and the hollow core is disposed between the magnet 16 and the inner wall portion 56 at four corners of the yoke 17. Coil 15. Next, the driving operation of the lens holder will be described with reference to Fig. 4. Fig. 4 is a longitudinal plan view of the lens driving device of Fig. 1 taken along a plane perpendicular to the diagonal. As shown in Fig. 4, the lens driving device is shown. In the first embodiment, since the magnet 16' is fixed to the four corners of the peripheral wall portion 55 of the yoke 17, and the inner wall portion 56 is provided with respect to the magnetic pole surface of the magnet 16, a magnetic circuit is formed at the four corners of the lens driving device 1. The magnetic flux generated by the magnetic pole surface of the magnet 16 passes through the hollow core The ring 15 is formed toward the inner wall portion 56. 'When the air-core coil 15 is energized in this state, the optical axis direction of the air-core coil 15 will generate an electromagnetic force. Then, the lens holder 14 resists the upper plate spring 18 and the lower plate spring 13 The ability to move by the electromagnetic force generated by the air core coil 15 in the direction of the optical axis adjusts the focal length of the lens (not shown) and the image sensor. In this case, the inner wall portion 56 of the yoke 17 and the magnet Since the magnetic pole faces of 16 are parallel, the amount of magnetic flux of the anger coil 15 is large by the 141246.doc •10·201007322, and a sufficient driving force can be generated even if the magnetic circuit is formed only at the four corners of the lens driving device 1. As described above, According to the lens driving device 1 of the present embodiment, since the outer peripheral wall portion 55 of the frame 17 has an octagonal inner peripheral surface, and the outer peripheral wall portion 55 is provided with the magnets 16 on the opposite sides thereof, it is formed on the four sides of the lens holder 14. The magnetic circuit can enlarge the mounting space of the lens compared to the case where the magnetic circuit is formed over the entire circumference of the lens holder 14. Further, since the mounting space of the lens can be enlarged, the cylindrical portion of the lens holder 14 can be formed in a cylindrical shape. 41. The lens unit can be mounted after the lens driving device 1 is mounted. Further, since the flat magnet 16 which is easy to process is used, the production cost can be reduced. Further, since the inner wall portion 56 is opposite to and parallel to the magnetic pole surface of the magnet 16 In this manner, the yoke 17' is formed so that the magnetic flux of the magnet 16 toward the air-core coil 15 is large, and a sufficient driving force can be obtained. Further, the configuration of the present embodiment is formed by forming the notch portion 57 between the adjacent inner wall portions 56. The inner wall portion 56 may be formed by cutting the inner wall portion 56 after forming a slit instead of the notch portion 57 between the adjacent inner wall portions 56. In this case, the coil support portion will not be formed on the outer peripheral surface of the cylindrical portion 41 of the lens holder 14. a 45-shaped bulge. Further, in the configuration of the present embodiment, the wall surface of the inner wall portion 56 is parallel to the magnetic pole surface of the magnet 16, but the wall surface of the inner wall portion 56 may be slightly inclined to the magnetic pole surface of the magnet 16. In this case, the driving force of the lens holder 14 is obtained by using a magnet having a strong magnetic force. 141246.doc 11 201007322 Further, all the points of the embodiments disclosed herein are merely illustrative, and the present invention is not limited to the embodiments. The scope of the present invention is not limited to the above-described embodiments, and is intended to cover all modifications within the meaning and scope of the application. [Industrial Applicability] As described above, the present invention has an effect of increasing the installation space of the lens, reducing the production cost, and obtaining sufficient driving force, and is particularly small for use in a mobile phone with a camera. Lens drive unit. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall perspective view showing a lens driving device according to an embodiment of a lens driving device of the present invention; FIG. 2 is a view showing a lens driving device of an embodiment of a lens driving device according to the present invention; 3 is a perspective view showing an embodiment of a lens driving device of the present invention, which is a cross-sectional view of a lens driving device with a horizontal plane cut away; and FIG. 4 shows an implementation of the lens driving device of the present invention. The figure of the form is a longitudinal section φ diagram of the lens driving device of Fig. 1 cut along a plane of a diagonal line. [Description of main components] 1 Lens drive unit 11 Lower case 12 Inner plate 14 Lens holder 15 Air core coil (lens drive unit) 141246.doc 201007322 16 17 19 45 55 56 57 Magnet (lens drive unit) Yoke ( Lens drive unit) Top cover coil support portion outer peripheral wall portion (outer wall portion) inner wall portion notch portion 141246.doc -13-