JP3826053B2

JP3826053B2 - Endoscope

Info

Publication number: JP3826053B2
Application number: JP2002060936A
Authority: JP
Inventors: 勝司渡辺
Original assignee: Olympus Corp
Current assignee: Olympus Corp
Priority date: 2002-03-06
Filing date: 2002-03-06
Publication date: 2006-09-27
Anticipated expiration: 2022-03-06
Also published as: JP2003260029A

Description

【０００１】
【発明の属する技術分野】
本発明は挿入部先端に固体撮像素子を設けた電子式内視鏡に関する。
【０００２】
【従来の技術】
一般に電子式内視鏡は術者が把持・操作する部位である操作部、体腔内に挿入する部位である挿入部及び上記操作部から延出したユニバーサルコードに設けられたコネクタを備えて構成される。内視鏡を使用するときは上記コネクタを光源装置や画像処理装置に接続する。挿入部の先端部位には体腔内を照明する照明光を導入するライトガイドや体腔内視野を撮像する撮像ユニット等が設けられ、照明した体腔内視野を撮像してその像をモニタ等に表示して観察するようになっている。
【０００３】
ところで、挿入部の先端部を構成する部材はその強度上金属で作られる。このため、何らの電気的絶縁処理を施さないと、体腔内で電気メス等の高周波処置具と併用して患部の処置を行うとき、高周波処置具の電極に接触している体液に高周波処置具に流れている高周波電流が漏洩し、この体液を通して漏洩した高周波電流が挿入部先端金属部分の露出箇所より内視鏡に流れ込み、操作部側へ流れてしまい、焼灼部位に十分な高周波電流が流れず、有効な処置ができない。また、固体撮像素子に高周波電流が流れた場合にはその固体撮像素子自体に異常をきたす虞がある。
【０００４】
そこで、これらの不都合を解決するため、例えば、特開平８−２９９２５８号公報に示されるように金属製の先端部材および挿入部外周を絶縁カバーおよび外装チューブで完全に覆うことで電気的に絶縁したり、特開２００１−４６３２２号公報に示されるように固体撮像素子と先端部材との間にセラミック製の絶縁枠を介在して設けて電気的に絶縁するようにしたり、あるいは特開昭６３−３１３９７０号公報に示されるように先端部材全体を一体にモールド成形したものが知られている。
【０００５】
【発明が解決しようとする課題】
しかしながら、特開平８−２９９２５８号公報に示される方式では先端部材および挿入部外周に絶縁部材を被覆するものであるため、その絶縁部材の厚み分、先端部が肉増しになる。また、その結果、挿入部の先端面から湾曲部までの先端硬質長が長くなったり、挿入部外径が太くなったりして、内視鏡の操作使用上、不利な構造になっていた。また、絶縁部材を被覆する方式であるため、部品数が増え、また、それらの組立作業が煩雑になるなどのデメリットもあった。
【０００６】
特開２００１−４６３２２号公報に示される方式では先端部材に固定された金属製のレンズ枠と固体撮像素子の両者を、別部材の絶縁枠を介して連結固定するため、絶縁枠はそれ自体の強度を持たせるようその厚肉を厚く形成する必要が生じる。その結果、撮像ユニット自体が大型化してしまい、挿入部を細径化するには不利な構造であった。また、この形式ではレンズ枠と固体撮像素子とは正確に位置決めして接合する必要があるため、絶縁枠を含む各部品に高度の寸法精度が要求され、部品原価が高くなるなどのデメリットもあった。
【０００７】
特開昭６３−３１３９７０号公報に示される方式では先端部本体全体が樹脂で一体にモールド成形したものであるため、先端部本体の強度が一般に乏しくなり、耐性上、問題がある。
【０００８】
本発明は上記事情に鑑みてなされたものであり、挿入部の外径を太くすることなく、かつ簡単・安価・強固な構造で内視鏡先端部と固体撮像素子との間の電気的絶縁対策を確実にとることができ、また、挿入部の先端部における限られた面積の中に、照明光を導光するライトガイドを効率よく配置可能であり、挿入部の細径化も同時に達成することのできる内視鏡を提供することを目的としている。
【０００９】
【課題を解決するための手段】
請求項１に係る発明は、固体撮像素子を挿入部先端に設けた内視鏡において、上記挿入部先端は、固体撮像素子を保持する先端部本体と、この先端部本体に組み付けられる先端枠と、この先端枠の外側に配置される外装用先端筒部材とを備え、上記先端枠と上記先端筒部材を金属製の略円筒状の部品で構成するとともに、上記先端枠の内部に上記先端部本体を配置し、更に、上記先端部本体を電気的絶縁性のある素材で形成したことを特徴とする内視鏡である。
請求項２に係る発明は、上記先端枠と上記先端部本体を組み合わせたとき、その部材間に形成した空間にライトガイドを配置したことを特徴とする請求項１の内視鏡である。
このような構成の発明によって、簡単・安価・強固な構造で、挿入部先端と固体撮像素子の確実な絶縁効果を得るとともに、挿入部の細径化も同時に達成可能とする。
【００１０】
【発明の実施の形態】
本発明の一実施形態に係る内視鏡を、図１乃至図１１を参照して具体的に説明する。
【００１１】
図１は本実施形態の内視鏡装置全体を示す斜視図、図２はその内視鏡の挿入部先端面を拡大して示す正面図、図３はその挿入部の先端近傍部分をその長手方向に沿って図２のＡ−Ａ線沿う面で縦断して示す断面図、図４は上記挿入部の先端近傍部分をその長手方向に沿って図２のＢ−Ｏ線に沿う面で縦断して示す断面図、図５は上記挿入部を図３のＣ−Ｃ線に沿う面で横断して示す断面図、図６は上記挿入部を図３のＤ−Ｄ線に沿う面で横断して示す断面図、図７は上記挿入部を図３のＥ−Ｅ線に沿う面で横断して示す断面図、図８は上記挿入部の先端部材と湾曲管との接合部における部分を図７の矢視Ｆの向きから見た外観図、図９は上記挿入部の先端近傍部分をその長手方向に沿って図５のＯ−Ｆ線に沿う面で縦断して示す断面図、図１０は上記挿入部の先端における位置決めピンを図９の矢視Ｇの向きから見た図、図１１は上記挿入部の先端部品を分解して示す斜視図である。
【００１２】
（構成）図１に示すように本実施形態の内視鏡１は例えば先端部側にＣＣＤ等の固体撮像素子を有する撮像ユニットを内蔵した細長な挿入部２と、この挿入部２の基端に設けられた把持部を兼ねる操作部３と、この操作部３の基端側から延設されたユニバーサルケーブル４と、このユニバーサルケーブル４の後端部に設けられ図示しない光源装置に接続されるライトガイドコネクタ５と、このライトガイドコネクタ５の側壁部から延出されたカメラケーブル６と、このカメラケーブル６の延出先端部に設けられ図示しないカメラコントロールユニット（以下ＣＣＵと呼ぶ）に接続されるカメラコネクタ７とを主な部分として構成されている。
尚、上記カメラコネクタ７が接続される図示しないＣＣＵには図示しないモニタが接続されるようになっていて、被検部の光学像を撮像ユニットの固体撮像素子で撮像した後、上記ＣＣＵで信号処理し、上記モニタでその被検部の画像を表示するようになっている。
【００１３】
上記挿入部２は最先端位置に先端部８を設け、この先端部８の基端に隣接して湾曲自在な湾曲部９を連設しており、さらに湾曲部９の基端に隣接して長尺で硬性の硬性部１０を連設した構成である。上記操作部３は硬性部１０の基端に連結される。操作部３の挿入部側部位は術者が内視鏡１を把持する把持部としてのグリップ１１を構成している。グリップ１１よりも手元側に位置する操作部３の部分には上記湾曲部９を異なる向きにそれぞれ湾曲操作するための２つの湾曲操作レバー１２ａ，１２ｂが設けられている。これらの湾曲操作レバー１２ａ，１２ｂをそれぞれ回動する操作を行なうことで、上記湾曲部９を湾曲することができる。上記湾曲操作レバー１２ａ，１２ｂに隣接する位置にはその湾曲操作レバー１２ａ，１２ｂを所望の位置で固定（すなわち湾曲状態を所望の状態で固定）するための湾曲固定レバー１３ａ（湾曲操作レバー１２ｂに対する湾曲固定レバー１３ｂについては不図示）が設けられている。上記グリップ１１には図示しないＶＴＲなどの映像記録装置や図示しないＣＣＵなどを遠隔操作する複数のリモートスイッチ１４が設けられている。
【００１４】
上記ライトガイドコネクタ５の側壁面には内視鏡本体の内外の連通状態を選択可能な通気口金１５が設けられていて、この通気口金１５より内視鏡本体内に空気を供給し、内視鏡１を水中に浸漬することにより気泡の漏れ等によって内視鏡１の水漏れ検査できるようになっている。通気口金１５は通常、閉塞されており、これによって内視鏡１の内部に水が浸入しない水密な状態にある。
【００１５】
上記挿入部２には主に湾曲部９の保護用としての保護シース１６が装着できる。この保護シース１６は可撓性の高いチューブ状のシース１７の部分と、そのシース１７の基端部に設けられた口元部１８の部分とから成る。上記挿入部２の先端部８を上記口元部１８の開口部分より差し込んで挿入部２をシース１７内に挿通させ、口元部１８の開口端部内面に設けた係合凸部１９をグリップ１１の先端側に設けたグリップ凸部２０を乗り越えて操作部３に係合させることで保護シース１６を内視鏡１に装着した状態で固定できるようになっている。
【００１６】
図２乃至図４に示すように上記挿入部２の先端部８には体腔内の被検部を照明するための照明光を導光して先端面に固定した照明窓２１から照明光を被検部に照射する照明光学系としてのライトガイド２２と、このライトガイド２２からの照明光で照明された被検部の光学像を取り入れ、ＣＣＤ等の固体撮像素子２３に結像させる対物光学系として、レンズ群２４を金属製のレンズ枠２５に組み込んだ構成の対物レンズ系２６と、上記固体撮像素子２３を内蔵した撮像部２７を備えた撮像ユニット２８とが設置されている。このライトガイド２２と撮像ユニット２８はいずれも上記先端部８の先端部本体２９に固定されている。ここで、ライトガイド２２は例えばライトガイドファイバ束によって形成され、そのファイバ束の断面形状はその端部近傍を接着剤などを用いて規定の形状に成形し、その他は変形自在なものである。
【００１７】
上記撮像ユニット２８の外装部品はそのユニット外径を小さく、かつ強度をもたせるため、金属製の薄肉円管部材３１より構成される。上記撮像ユニット２８の外周面は例えば樹脂製の電気的絶縁性チューブ３２で被覆されており、このチューブ３２で外装金属部との電気的絶縁をとっている。
【００１８】
上記撮像ユニット２８において、上記固体撮像素子２３の後ろ側には電子回路基板３３を介して撮像ケーブル３４が接続されている。この撮像ケーブル３４は内視鏡１の挿入部２、操作部３、ユニバーサルケーブル４、ライトガイドコネクタ５及びカメラケーブル６内を通じて、上記カメラコネクタ７に導かれ、そのカメラコネクタ７により図示しないビデオプロセッサ等に接続される。
【００１９】
図１１に示すように、上記挿入部２の先端部８の基体は大きく分けて、上記先端部本体２９と、この先端部本体２９に被嵌される略円筒状の先端枠３５と、この先端枠３５に外装部分として被嵌される略円筒状の先端円筒部材３６の３つの先端部品により構成されている。
【００２０】
上記先端部本体２９は樹脂やセラミックなどの電気的導電性の無い素材により形成されている。先端部本体２９の略中央には上記撮像ユニット２８の先端部分を嵌入して、上記撮像ユニット２８を水密的に固定する対物収納孔３７が形成されている。図３及び図５に示すように、先端部本体２９には対物収納孔３７に直交するようにネジ孔３８が形成されており、そのネジ孔３８には先端部本体２９の下方からビス３９がねじ込まれ、このビス３９によって撮像ユニット２８を先端部本体２９に固定する。このビス固定後はねじ込み部の水密を確保するため、残ったネジ孔３８内には充填材４１を密に充填する。
【００２１】
図１１に示すように、先端部本体２９の外周部には接着剤などで断面形状を略矩形の形状に成形することにより上記ライトガイド２２の端部が配置される略矩形溝のライトガイド受け部２９ｂが形成されている。また、挿入部２の先端面として外部に露出する面側の、上記ライトガイド受け部２９ｂが形成された位置には平板ガラスより成る照明窓２１を落とし込むための段部２９ｄが形成されている。この段部２９ｄが切り欠かれていない部分はフランジ状の部分として残り、このフランジ部２９ｅは上記先端枠３５を組み付ける際の突き当て位置決め部となる。また、図１１に示すように先端部本体２９の他の外周部には上記３部品の位置決め用としてのピン４０を係入する位置決め穴２９ｃが所定の位置に設けられている。
【００２２】
上記先端枠３５は薄肉で金属製の円管形状を成し、その一端は段付き肉厚部３５ｃとし、その開口部には上記先端部本体２９を嵌入したとき、各々の端部が同面となるよう先端部本体２９のフランジ部２９ｅが当接する当接部３５ａを形成している。他端側からは一定幅のスリット状の切欠き部３５ｂを設け、図６に示すように撮像ユニット２８の最大外径の周辺部分を入り込ませて撮像ユニット２８と先端枠３５の干渉を無くし、挿入部外径寸法を小さく抑えている。さらに先端枠３５には上記ピン４０を係入させる穴３５ｄが所定の位置に設けられていて、上記ピン４０により、先端部本体２９と先端枠３５の位置を決めるようになっている。
【００２３】
図１１に示すように上記先端円筒部材３６は金属製の薄肉円管状を成しており、その先端側筒状部分は上記先端枠３５の外周にぴったりと嵌入する内径の太径筒部３６ａとなっている。先端円筒部材３６の後端側部分は段付きの細径部３６ｂとなっている。先端円筒部材３６の太径筒部３６ａにおける先端部分にはスリット３６ｃが形成されている。上記スリット３６ｃの幅は上記ピン４０の細径部４０ａの直径と略等しい。そして、先端円筒部材３６内に先端枠３５を嵌入させ、先端円筒部材３６の先端が先端枠３５の肉厚部３５ｃの段付き部に当接する際、先端円筒部材３６のスリット３６ｃに上記ピン４０の細径部４０ａを係入させるようにして相互の位置関係を決めるようになっている。
【００２４】
すなわち、図９及び図１０に示すように、上記ピン４０を先端部本体２９と先端枠３５の位置決め穴３５ｄに嵌め込んだのち、上記先端枠３５の外周面に突き出した上記ピン４０の細径部４０ａを、その直径と略等しい幅のスリット３６ｃに係入させるようにして先端円筒部材３６を先端枠３５に組み付けることにより、上記３つの先端部品相互の位置を決めると共に上記ピン４０の脱落を防止する。さらに上記ピン４０は先端部本体２９が先端枠３５から脱落することを防止する。なお、先端枠３５と先端円筒部材３６との接合は両者の嵌合長さを十分にとることによって接着面積を増し、両者の接着強度を確保する。
【００２５】
上記先端円筒部材３６の他端側部分は段付き細径部３６ｂを成しているが、この段付き細径部３６ｂには図３に示すように挿入部２の湾曲部９の外装芯部材を構成する節輪４３の最先端に位置するものの一端部分が嵌合しており、さらに両者は接着固定される。このとき、図７及び図１１に示すように、節輪４３に内嵌する段付き細径部３６ｂの所定位置にはカシメ孔４４が設けられており、細径部３６ｂに外嵌する上記節輪４３の同位置部分をＵ字状に切欠くことによって節輪４３に舌片４５を設ける（図８を参照）。この舌片４５は図７のように上記カシメ孔４４に係入するように内側に折り曲げる。上記カシメ孔４４に舌片４５を係止しているため、万一、部品同士の接着部が剥離することがあっても部品同士が離脱することが無い。
【００２６】
上記舌片４５は節輪４３の円周方向に向かって舌部が設けられるため、上記先端円筒部材３６と上記節輪４３の嵌合代を短く構成し、結果として先端硬質長の短縮を図ることができる。仮に、舌片４５の舌部を挿入部２の長手方向に設けると、充分な折り曲げ代を確保するために嵌合代は舌片４５の長さに必然的に合わせて長くする必要がある。この場合、節輪４３の開口端が舌片４５の折曲げ部に近いと、開口部が変形してしまう虞があるため、さらに長手方向に十分な余裕が必要となる。
【００２７】
内視鏡１の挿入部２の先端部８において一端部分を固定したライトガイド２２はその基端が上記ライトガイドコネクタ５に固定され、図示しない光源装置からの照明光をそのライトガイド２２を通じて挿入部先端まで導光する。ライトガイド２２の先端部分は左右に分かれて上記先端部本体２９の略矩形溝のライトガイド受け部２９ｂ内に密な状態でそれぞれ配置される。上記先端部本体２９と上記先端枠３５とで構成される凹部空間内に配置される。つまり、上記先端部本体２９と上記先端枠３５を組み合わせたとき、その部材間に位置して形成される空間内に照明用のファイバー束のライトガイド２２が密に配置される。
【００２８】
そして、このライトガイド２２を通じて送り込まれた照明光は先端部８の端部において上記先端部本体２９と上記先端枠３５とで構成される凹部（すなわち上記ライトガイド２２の出射端部）に接着固定された照明窓２１（図２を参照）を通して被検部に出射される。
【００２９】
また、図４および図６に示すように上記ライトガイド２２は挿入部２の先端部８に配置されるが、この場合、先端枠３５の内部において、上記撮像ユニット２８を避けた部位及び空間を利用して効率良く配置されるため、挿入部２の細径化を達成する。また、ライトガイド２２を略矩形（扁平）に成形することで、先端部８内のデットスペースをより少なくすることができる。さらに図４に示すように撮像ユニット２８の最大外径部分を避けるように長手方向に沿ってライトガイド成形部をＳ字状にして配置し、その組立性を向上させている。また、ライトガイド２２の成形部に組立時や湾曲操作時のストレスがかかってもライトガイド２２の素線を折れにくくするために先端枠３５の長手方向全長にわたり、その先端枠３５の内周面とライトガイド２２との側面を接着固定するようにする。
【００３０】
また、先端部８にライトガイド２２を配置するためにはその先端部８にライトガイド成形部と略同形状の挿通孔が必要になるが、本実施形態においては先端部本体２９と先端枠３５の２部品の組み合せにより出来る空間を利用して矩形（或いは円形以外の異形)の挿通孔を形成している。
【００３１】
（作用）本構成の内視鏡観察下において、高周波処置具を用い、治療を行う。高周波処置具の通電中、内視鏡１の挿入部２が患者の組織に触れても、内視鏡１の先端部８と撮像ユニット２８とは非導電性の先端部本体２９が介在しているので、撮像ユニット２８を経由して内視鏡側に高周波電流が漏洩することが無い。また、挿入部外装金属はコネクタ部で電気的に絶縁されているため、光源装置あるいはビデオプロセッサに高周波電流が漏洩することがない。
【００３２】
（効果）本実施形態においては先端部品を複数の部品で構成し、また、撮像ユニット２８を保持する先端部品としての先端部本体２９を電気的絶縁部材で構成したことにより、挿入部外装と撮像ユニット２８の間に確実な絶縁効果が得られるため、安全・確実な高周波処置が可能となる。さらに、挿入部先端や挿入部外周に絶縁被覆部材を設ける必要がないので、先端硬質長を短くかつ挿入部外径を細くすることができ、内視鏡の操作性向上につながる。また、従来、撮像ユニット内部に設けていた寸法精度が要求される絶縁部品が不要となるので原価低減や撮像ユニット自体の組立作業の簡略化が可能となる。
【００３３】
固体撮像素子２３とレンズ枠２５との間に絶縁部材を介在させる必要が無く、薄肉の金属枠で接合させることができるので挿入部２の細径化が可能となる。
【００３４】
複数部品で構成した先端部品のうち、非導電性の先端部本体２９を外装する先端枠３５や先端円筒部材３６等の先端部品を金属パイプで構成することにより、十分な強度を確保することができる。
【００３５】
挿入部２を細径化するために、その先端部８におけるスペースの有効利用を計り、略矩形（或いは円形以外の異形）のライトガイド２２を先端部８に配置させる場合、１部品にライトガイド固定用の挿通孔を精度良く加工することは非常に難しく、加工コストも高くなる。しかし、本実施形態においては２部品の接合部分に略矩形孔を形成するようにしたので、その加工が容易となり、加工コストが低減される。
【００３６】
尚、本発明は前述した実施形態に限定されるものではなく、他の形態にも適用が可能である。
【００３７】
＜付記＞
付記項１．固体撮像素子を挿入部先端に設けた内視鏡において、
上記挿入部先端を複数の先端部品を組み合せて構成し、そのうち少なくとも上記固体撮像素子を保持する先端部品を電気的絶縁性のある素材で形成したことを特徴とする内視鏡。
付記項２．上記挿入部先端を構成する複数部品のうち、外装部分の先端部品を金属製の円筒部品で構成するとともに、上記固体撮像素子を保持する先端部品をその金属製の円筒部品の内部に配置したことを特徴とする付記項１の内視鏡。
付記項３．上記金属製の円筒部品と上記固体撮像素子を保持する先端部品の組み合わせることによって形成される空間に照明用のファイバー束を配置したことを特徴とする付記項１の内視鏡。
【００３８】
付記項４．上記複数の先端部品の各々に対し、相互の組付け状態を規定するための位置決め手段を設けた付記項１の内視鏡。
付記項５．上記位置決め手段が、太径部と細径部とを有する段付き形状のピン部材と、これが嵌入あるいは係合する先端部品に設けた孔あるいはスリットであり、上記ピン部材の細径部が上記先端部品の最外装部品に設けたスリットに係入するよう構成した付記項４の内視鏡。
付記項６．先端部品とこれに連接する挿入部との接合がパイプ状部品の嵌合からなり、内嵌する部品に設けた孔に対し、外嵌する部品にＵ字状のスリットを設けて形成した舌片を折り曲げ、係合させるようにした付記項１の内視鏡。
付記項７．上記舌片の方向を、上記パイプ状部品の円周方向に設けた付記項６の内視鏡。
【００３９】
【発明の効果】
以上説明したように本発明によれば、簡単な構造、少ない部品数で、挿入部外径の細径化を図りつつ、挿入部外装と撮像ユニットの間の確実な電気的絶縁を行うことができるという効果がある。
【図面の簡単な説明】
【図１】本発明の一実施形態に係る内視鏡装置全体を示す斜視図である。
【図２】本実施形態に係る内視鏡の挿入部先端面を拡大して示す正面図である。
【図３】本実施形態に係る内視鏡の挿入部の先端近傍部分をその長手方向に沿って図２のＡ−Ａ線沿う面で縦断して示す断面図である。
【図４】上記挿入部の先端近傍部分をその長手方向に沿って図２のＢ−Ｏ線に沿う面で縦断して示す断面図である。
【図５】上記挿入部を図３のＣ−Ｃ線に沿う面で横断して示す断面図である。
【図６】上記挿入部を図３のＤ−Ｄ線に沿う面で横断して示す断面図である。
【図７】上記挿入部を図３のＥ−Ｅ線に沿う面で横断して示す断面図である。
【図８】上記挿入部の先端部材と湾曲管との接合部における図７の矢視Ｆの向きから見た外観図である。
【図９】上記挿入部の先端近傍部分をその長手方向に沿って図５のＯ−Ｆ線に沿う面で縦断して示す断面図である。
【図１０】上記挿入部の先端における位置決めピンを図９の矢視Ｇの向きから見た図である。
【図１１】上記挿入部の先端部品を分解して示す斜視図である。
【符号の説明】
１…内視鏡
２…挿入部
３…操作部
４…ユニバーサルケーブル
５…ライトガイドコネクタ
６…カメラケーブル
７…カメラコネクタ
８…先端部
９…湾曲部
１０…硬性部
１１…グリップ
２１…照明窓
２２…ライトガイド
２３…固体撮像素子
２６…対物レンズ系
２７…撮像部
２８…撮像ユニット
２９…先端部本体
３３…電子回路基板
３４…撮像ケーブル
３５…先端枠
３６…先端円筒部材
３６…円筒部材[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic endoscope in which a solid-state image sensor is provided at the distal end of an insertion portion.
[0002]
[Prior art]
In general, an electronic endoscope is configured to include an operation unit that is a part that an operator grasps and operates, an insertion part that is a part that is inserted into a body cavity, and a connector that is provided on a universal cord extending from the operation part. The When using an endoscope, the connector is connected to a light source device or an image processing device. A light guide for introducing illumination light for illuminating the inside of the body cavity and an imaging unit for imaging the in-vivo field of view are provided at the distal end portion of the insertion portion, and the illuminated in-vivo field of view is imaged and displayed on a monitor or the like. To observe.
[0003]
By the way, the member which comprises the front-end | tip part of an insertion part is made with the metal on the strength. For this reason, when no electrical insulation treatment is performed, the high-frequency treatment instrument is applied to the body fluid that is in contact with the electrode of the high-frequency treatment instrument when the affected area is treated in combination with a high-frequency treatment instrument such as an electric knife within the body cavity. The high-frequency current flowing in the body fluid leaks, and the high-frequency current leaked through this body fluid flows into the endoscope from the exposed portion of the insertion portion tip metal part and flows to the operation unit side, so that sufficient high-frequency current flows to the ablation site. Therefore, effective treatment cannot be performed. Further, when a high-frequency current flows through the solid-state image sensor, there is a risk that the solid-state image sensor itself may be abnormal.
[0004]
Therefore, in order to solve these disadvantages, for example, as shown in JP-A-8-299258, the metal tip member and the outer periphery of the insertion portion are completely covered with an insulating cover and an outer tube so as to be electrically insulated. Or, as disclosed in Japanese Patent Laid-Open No. 2001-46322, a ceramic insulating frame is interposed between the solid-state imaging device and the tip member so as to be electrically insulated, or Japanese Patent Laid-Open No. 63-63. As shown in Japanese Patent No. 313970, one in which the entire tip member is integrally molded is known.
[0005]
[Problems to be solved by the invention]
However, in the method disclosed in Japanese Patent Application Laid-Open No. 8-299258, since the tip member and the outer periphery of the insertion portion are covered with an insulating member, the tip portion is thickened by the thickness of the insulating member. As a result, the distal end rigid length from the distal end surface of the insertion portion to the curved portion is increased, or the outer diameter of the insertion portion is increased, resulting in an unfavorable structure for use of the endoscope. In addition, since the insulating member is coated, the number of parts is increased and the assembling work thereof is complicated.
[0006]
In the method disclosed in Japanese Patent Application Laid-Open No. 2001-46322, both the metal lens frame fixed to the tip member and the solid-state imaging device are connected and fixed via an insulating frame as a separate member. The thick wall needs to be formed thick so as to have strength. As a result, the imaging unit itself is increased in size, which is a disadvantageous structure for reducing the diameter of the insertion portion. In this format, the lens frame and the solid-state image sensor must be accurately positioned and joined, so that each part including the insulating frame requires a high degree of dimensional accuracy, and there are also disadvantages such as high part costs. It was.
[0007]
In the method disclosed in Japanese Patent Laid-Open No. 63-313970, since the entire tip body is integrally molded with resin, the strength of the tip body is generally poor, and there is a problem with durability.
[0008]
The present invention has been made in view of the above circumstances, and does not increase the outer diameter of the insertion portion, and it is an electrical insulation between the endoscope distal end portion and the solid-state imaging device with a simple, inexpensive, and strong structure. Measures can be taken reliably, and the light guide that guides the illumination light can be efficiently placed in the limited area at the tip of the insertion section, and the insertion section can be made thinner at the same time. It aims at providing the endoscope which can do.
[0009]
[Means for Solving the Problems]
The invention according to claim 1 is an endoscope in which a solid-state imaging device is provided at the distal end of the insertion portion, wherein the distal end of the insertion portion is a distal-end portion main body that holds the solid-state imaging device, and a distal-end frame that is assembled to the distal-end portion main body. A front end cylindrical member disposed outside the front end frame, and the front end frame and the front end cylindrical member are made of a substantially cylindrical part made of metal , and the front end portion is formed inside the front end frame. The endoscope is characterized in that a main body is disposed, and further, the distal end body is formed of an electrically insulating material.
The invention according to claim 2, when a combination of the tip frame and the distal end portion main body, an endoscope according to claim 1, characterized in that a light guide space formed between the members.
According to the invention having such a configuration, it is possible to obtain a reliable insulating effect between the distal end of the insertion portion and the solid-state imaging device with a simple, inexpensive, and strong structure, and to simultaneously reduce the diameter of the insertion portion.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
An endoscope according to an embodiment of the present invention will be specifically described with reference to FIGS.
[0011]
FIG. 1 is a perspective view showing the entire endoscope apparatus of the present embodiment, FIG. 2 is an enlarged front view showing the distal end surface of the insertion portion of the endoscope, and FIG. 3 is a longitudinal view of the vicinity of the distal end of the insertion portion. FIG. 4 is a cross-sectional view taken along the line AA in FIG. 2 along the direction, and FIG. 4 is a longitudinal section along the longitudinal direction of the portion near the tip of the insertion part along the line B-O in FIG. FIG. 5 is a cross-sectional view of the insertion portion taken along the line CC in FIG. 3, and FIG. 6 is a cross-section of the insertion portion along the line DD in FIG. FIG. 7 is a cross-sectional view of the insertion portion taken along the line EE in FIG. 3, and FIG. 8 is a cross-sectional view of the insertion portion between the distal end member and the bending tube. FIG. 9 is an external view as seen from the direction of arrow F in FIG. 7, and FIG. 9 is a cross-sectional view showing the vicinity of the distal end of the insertion section along the longitudinal direction along the line O-F in FIG. 1 The view of the positioning pin at the tip of the insertion portion from the direction of arrow G in FIG. 9, FIG. 11 is an exploded perspective view of the distal end part of the insertion portion.
[0012]
(Configuration) As shown in FIG. 1, an endoscope 1 according to the present embodiment includes, for example, an elongated insertion portion 2 containing an imaging unit having a solid-state imaging device such as a CCD on the distal end side, and a proximal end of the insertion portion 2 The operation unit 3 also serving as a gripping unit provided on the universal cable 4, a universal cable 4 extending from the proximal end side of the operation unit 3, and a light source device (not shown) provided at the rear end of the universal cable 4. The light guide connector 5, the camera cable 6 extending from the side wall portion of the light guide connector 5, and a camera control unit (hereinafter referred to as “CCU”) provided at the extending distal end portion of the camera cable 6. The camera connector 7 is a main part.
Note that a monitor (not shown) is connected to the CCU (not shown) to which the camera connector 7 is connected. After an optical image of the test part is picked up by the solid-state image pickup device of the image pickup unit, the signal is sent from the CCU. The processed image is displayed on the monitor.
[0013]
The insertion portion 2 is provided with a distal end portion 8 at the foremost position, and a bendable bending portion 9 is provided adjacent to the proximal end of the distal end portion 8, and further adjacent to the proximal end of the bending portion 9. This is a configuration in which long and hard rigid portions 10 are continuously provided. The operation unit 3 is connected to the proximal end of the rigid unit 10. The insertion portion side portion of the operation portion 3 constitutes a grip 11 as a grasping portion where the operator grasps the endoscope 1. Two bending operation levers 12a and 12b for bending the bending portion 9 in different directions are provided at the portion of the operation portion 3 located closer to the hand than the grip 11. The bending portion 9 can be bent by performing an operation of rotating these bending operation levers 12a and 12b. In a position adjacent to the bending operation levers 12a and 12b, a bending fixing lever 13a (for the bending operation lever 12b) for fixing the bending operation levers 12a and 12b at a desired position (that is, fixing the bending state in a desired state). A curved fixing lever 13b is provided (not shown). The grip 11 is provided with a plurality of remote switches 14 for remotely operating a video recording device such as a VTR (not shown) or a CCU (not shown).
[0014]
The side wall surface of the light guide connector 5 is provided with a vent base 15 capable of selecting the internal / external communication state of the endoscope main body, and air is supplied from the vent base 15 into the endoscope main body. By immersing the mirror 1 in water, the endoscope 1 can be inspected for water leakage due to leakage of bubbles or the like. The vent cap 15 is normally closed, and thus is in a watertight state in which water does not enter the endoscope 1.
[0015]
A protective sheath 16 mainly for protecting the bending portion 9 can be attached to the insertion portion 2. The protective sheath 16 is composed of a highly flexible tube-shaped sheath 17 portion and a mouth portion 18 portion provided at the base end portion of the sheath 17. The distal end portion 8 of the insertion portion 2 is inserted from the opening portion of the mouth portion 18 so that the insertion portion 2 is inserted into the sheath 17, and the engaging convex portion 19 provided on the inner surface of the opening end portion of the mouth portion 18 is formed on the grip 11. The protective sheath 16 can be fixed in a state of being attached to the endoscope 1 by overcoming the grip convex portion 20 provided on the distal end side and engaging with the operation portion 3.
[0016]
As shown in FIGS. 2 to 4, the distal end portion 8 of the insertion portion 2 receives illumination light from an illumination window 21 that guides illumination light for illuminating the test portion in the body cavity and is fixed to the distal end surface. A light guide 22 as an illumination optical system that irradiates the inspection unit, and an objective optical system that takes an optical image of the test unit illuminated by illumination light from the light guide 22 and forms an image on a solid-state imaging device 23 such as a CCD. As shown, an objective lens system 26 having a configuration in which the lens group 24 is incorporated in a metal lens frame 25 and an imaging unit 28 having an imaging unit 27 incorporating the solid-state imaging element 23 are installed. Both the light guide 22 and the imaging unit 28 are fixed to the tip body 29 of the tip 8. Here, the light guide 22 is formed of, for example, a light guide fiber bundle, and the cross-sectional shape of the fiber bundle is formed in a prescribed shape using an adhesive or the like in the vicinity of the end portion, and the others are freely deformable.
[0017]
The exterior part of the image pickup unit 28 is composed of a metal thin circular tube member 31 in order to reduce the outer diameter of the unit and to provide strength. The outer peripheral surface of the imaging unit 28 is covered with an electrically insulating tube 32 made of resin, for example, and the tube 32 is electrically insulated from the exterior metal part.
[0018]
In the imaging unit 28, an imaging cable 34 is connected to the rear side of the solid-state imaging device 23 via an electronic circuit board 33. The imaging cable 34 is guided to the camera connector 7 through the insertion portion 2, the operation portion 3, the universal cable 4, the light guide connector 5 and the camera cable 6 of the endoscope 1, and a video processor (not shown) is connected to the camera connector 7. Connected to etc.
[0019]
As shown in FIG. 11, the base of the distal end portion 8 of the insertion portion 2 is roughly divided into the distal end portion main body 29, a substantially cylindrical distal end frame 35 fitted on the distal end portion main body 29, and the distal end. It is constituted by three tip parts of a substantially cylindrical tip cylindrical member 36 fitted as an exterior part to the frame 35.
[0020]
The tip body 29 is made of a material having no electrical conductivity such as resin or ceramic. An objective accommodation hole 37 for fitting the distal end portion of the imaging unit 28 and fixing the imaging unit 28 in a watertight manner is formed in the approximate center of the distal end portion main body 29. As shown in FIGS. 3 and 5, a screw hole 38 is formed in the tip portion main body 29 so as to be orthogonal to the objective accommodation hole 37, and a screw 39 is inserted into the screw hole 38 from below the tip portion main body 29. The image pickup unit 28 is fixed to the tip end body 29 by the screw 39. After the screws are fixed, the remaining screw hole 38 is filled with a filler 41 in order to ensure water tightness of the screwed portion.
[0021]
As shown in FIG. 11, a light guide receiver having a substantially rectangular groove in which the end of the light guide 22 is disposed on the outer peripheral portion of the tip body 29 by forming the cross-sectional shape into a substantially rectangular shape with an adhesive or the like. A portion 29b is formed. Further, a step portion 29d for dropping the illumination window 21 made of flat glass is formed at a position where the light guide receiving portion 29b is formed on the surface exposed to the outside as the distal end surface of the insertion portion 2. The portion where the step portion 29d is not cut out remains as a flange-like portion, and the flange portion 29e serves as an abutment positioning portion when the tip frame 35 is assembled. Further, as shown in FIG. 11, a positioning hole 29c for engaging the pin 40 for positioning the three parts is provided at a predetermined position on the other outer peripheral portion of the tip end body 29.
[0022]
The distal end frame 35 has a thin and metal circular tube shape, one end of which is a stepped thick portion 35c, and when the distal end main body 29 is fitted into the opening, each end is flush. A contact portion 35a with which the flange portion 29e of the tip end body 29 contacts is formed. A slit-shaped notch 35b having a constant width is provided from the other end side, and the peripheral portion of the maximum outer diameter of the imaging unit 28 is inserted as shown in FIG. 6 to eliminate the interference between the imaging unit 28 and the distal end frame 35. The outer diameter of the insertion part is kept small. Further, a hole 35d for engaging the pin 40 is provided at a predetermined position in the distal end frame 35, and the positions of the distal end main body 29 and the distal end frame 35 are determined by the pin 40.
[0023]
As shown in FIG. 11, the distal end cylindrical member 36 has a thin circular tube made of metal, and the distal end side tubular portion thereof has a large diameter tubular portion 36a having an inner diameter that fits snugly into the outer periphery of the distal end frame 35. It has become. The rear end side portion of the distal end cylindrical member 36 is a stepped narrow diameter portion 36b. A slit 36 c is formed at the distal end portion of the large diameter cylindrical portion 36 a of the distal end cylindrical member 36. The width of the slit 36c is substantially equal to the diameter of the small diameter portion 40a of the pin 40. Then, when the distal end frame 35 is fitted into the distal end cylindrical member 36 and the distal end of the distal end cylindrical member 36 contacts the stepped portion of the thick portion 35 c of the distal end frame 35, the pin 40 is inserted into the slit 36 c of the distal end cylindrical member 36. The mutual positional relationship is determined by engaging the small-diameter portion 40a.
[0024]
That is, as shown in FIG. 9 and FIG. 10, after the pin 40 is fitted into the positioning hole 35 d of the tip body 29 and the tip frame 35, the small diameter of the pin 40 protruding from the outer peripheral surface of the tip frame 35. By assembling the distal end cylindrical member 36 to the distal end frame 35 so that the portion 40a is engaged with a slit 36c having a width substantially equal to the diameter thereof, the positions of the three distal end components are determined and the pin 40 is removed. To prevent. Further, the pin 40 prevents the tip body 29 from falling off the tip frame 35. In addition, joining of the front-end | tip frame 35 and the front-end | tip cylindrical member 36 increases a bonding area by taking sufficient fitting length of both, and ensures both adhesive strength.
[0025]
The other end portion of the tip cylindrical member 36 forms a stepped small diameter portion 36b. The stepped small diameter portion 36b includes an outer core member of the bending portion 9 of the insertion portion 2 as shown in FIG. One end portion of the node ring 43 that is located at the foremost part of the joint ring 43 is fitted, and both are bonded and fixed. At this time, as shown in FIGS. 7 and 11, a caulking hole 44 is provided at a predetermined position of the stepped small-diameter portion 36b fitted into the node ring 43, and the above-mentioned node fitted outside the small-diameter portion 36b. A tongue piece 45 is provided on the node ring 43 by cutting out the same position portion of the ring 43 into a U-shape (see FIG. 8). The tongue piece 45 is bent inward so as to engage with the caulking hole 44 as shown in FIG. Since the tongue piece 45 is locked in the caulking hole 44, the parts do not come apart even if the bonding portion between the parts is peeled off.
[0026]
Since the tongue piece 45 is provided with a tongue portion in the circumferential direction of the node ring 43, the fitting margin between the tip cylindrical member 36 and the node ring 43 is shortened, and as a result, the tip rigid length is shortened. be able to. If the tongue portion 45 of the tongue piece 45 is provided in the longitudinal direction of the insertion portion 2, it is necessary to make the fitting allowance longer in accordance with the length of the tongue piece 45 in order to ensure a sufficient bending margin. In this case, if the opening end of the node ring 43 is close to the bent portion of the tongue piece 45, the opening may be deformed, so that a sufficient margin in the longitudinal direction is required.
[0027]
The light guide 22 having one end fixed at the distal end portion 8 of the insertion portion 2 of the endoscope 1 is fixed at the base end to the light guide connector 5, and illumination light from a light source device (not shown) is inserted through the light guide 22. The light is guided to the tip of the part. The front end portion of the light guide 22 is divided into left and right portions and is arranged in a dense state in the light guide receiving portion 29b of the substantially rectangular groove of the front end portion main body 29. It is disposed in a recessed space constituted by the tip portion main body 29 and the tip frame 35. That is, when the distal end body 29 and the distal end frame 35 are combined, the light guides 22 of the fiber bundle for illumination are densely arranged in a space formed between the members.
[0028]
The illumination light sent through the light guide 22 is bonded and fixed at the end portion of the tip end portion 8 to a concave portion formed by the tip portion main body 29 and the tip end frame 35 (that is, the emission end portion of the light guide 22). The light is emitted to the test part through the illuminated window 21 (see FIG. 2).
[0029]
4 and 6, the light guide 22 is disposed at the distal end portion 8 of the insertion portion 2. In this case, a portion and a space avoiding the imaging unit 28 in the distal end frame 35 are provided. Since it is efficiently arranged by using, the diameter of the insertion portion 2 is reduced. Moreover, the dead space in the front-end | tip part 8 can be decreased more by shape | molding the light guide 22 in a substantially rectangular shape (flat). Further, as shown in FIG. 4, the light guide molding portion is arranged in an S shape along the longitudinal direction so as to avoid the maximum outer diameter portion of the image pickup unit 28, thereby improving the assemblability. The inner peripheral surface of the distal end frame 35 extends over the entire length of the distal end frame 35 in order to make it difficult to break the strands of the light guide 22 even when stress is applied to the molded portion of the light guide 22 during assembly or bending operation. And the side surfaces of the light guide 22 are bonded and fixed.
[0030]
Further, in order to arrange the light guide 22 at the distal end portion 8, an insertion hole having substantially the same shape as the light guide molded portion is required at the distal end portion 8. In the present embodiment, the distal end portion main body 29 and the distal end frame 35 are provided. A rectangular (or irregular shape other than circular) insertion hole is formed using a space formed by combining the two parts.
[0031]
(Operation) Under the endoscope observation of this configuration, treatment is performed using a high-frequency treatment tool. Even when the insertion portion 2 of the endoscope 1 touches the patient's tissue while the high-frequency treatment instrument is energized, the distal end portion 8 of the endoscope 1 and the imaging unit 28 are interposed by the non-conductive distal end portion main body 29. Therefore, no high-frequency current leaks to the endoscope side via the imaging unit 28. Further, since the outer metal of the insertion portion is electrically insulated at the connector portion, the high frequency current does not leak to the light source device or the video processor.
[0032]
(Effect) In the present embodiment, the tip part is composed of a plurality of parts, and the tip part main body 29 as the tip part for holding the imaging unit 28 is constructed of an electrically insulating member, so that the insertion part exterior and the imaging part are captured. Since a reliable insulation effect is obtained between the units 28, a safe and reliable high-frequency treatment can be performed. Furthermore, since there is no need to provide an insulating coating member at the distal end of the insertion portion or the outer periphery of the insertion portion, the distal end rigid length can be shortened and the outer diameter of the insertion portion can be reduced, leading to improved operability of the endoscope. In addition, since it is not necessary to provide an insulating part that requires a dimensional accuracy, which is conventionally provided in the imaging unit, the cost can be reduced and the assembling work of the imaging unit itself can be simplified.
[0033]
There is no need to interpose an insulating member between the solid-state imaging device 23 and the lens frame 25, and the thin portion can be joined with a thin metal frame, so that the diameter of the insertion portion 2 can be reduced.
[0034]
Of the tip parts composed of a plurality of parts, the tip parts such as the tip frame 35 and the tip cylindrical member 36 that sheath the non-conductive tip part main body 29 are made of metal pipes, thereby ensuring sufficient strength. it can.
[0035]
In order to reduce the diameter of the insertion portion 2, the space at the distal end portion 8 is effectively used, and when a light guide 22 having a substantially rectangular shape (or an irregular shape other than a circle) is disposed at the distal end portion 8, the light guide is a single component. It is very difficult to accurately process the fixing insertion hole, and the processing cost is increased. However, in the present embodiment, since a substantially rectangular hole is formed at the joining part of the two parts, the processing becomes easy and the processing cost is reduced.
[0036]
In addition, this invention is not limited to embodiment mentioned above, It can apply also to another form.
[0037]
<Appendix>
Additional Notes 1. In an endoscope provided with a solid-state image sensor at the distal end of the insertion portion,
An endoscope characterized in that the distal end of the insertion portion is formed by combining a plurality of distal end components, and at least the distal end component for holding the solid-state imaging device is formed of a material having electrical insulation properties.
Additional Item 2. Among the plurality of parts constituting the distal end of the insertion portion, the tip part of the exterior part is made of a metal cylindrical part, and the tip part holding the solid-state imaging device is arranged inside the metal cylindrical part The endoscope of Additional remark 1 characterized by these.
Additional Item 3. The endoscope according to additional item 1, wherein a fiber bundle for illumination is arranged in a space formed by combining the metal cylindrical part and the tip part holding the solid-state imaging device.
[0038]
Additional Item 4. The endoscope according to additional item 1, wherein positioning means for defining a mutual assembly state is provided for each of the plurality of tip parts.
Additional Item 5. The positioning means is a stepped pin member having a large diameter portion and a small diameter portion, and a hole or a slit provided in a tip part into which the pin member is fitted or engaged, and the small diameter portion of the pin member is the tip end The endoscope according to additional item 4, configured to engage with a slit provided in an outermost part of the part.
Additional Item 6. A tongue piece formed by providing a U-shaped slit in a part to be externally fitted to a hole provided in a part to be internally fitted, in which a joint between a tip part and an insertion portion connected thereto is formed by fitting a pipe-like part. The endoscope according to additional item 1, wherein the endoscope is bent and engaged.
Additional Item 7. The endoscope according to additional item 6, wherein a direction of the tongue piece is provided in a circumferential direction of the pipe-shaped part.
[0039]
【The invention's effect】
As described above, according to the present invention, it is possible to perform reliable electrical insulation between the exterior of the insertion portion and the imaging unit while reducing the outer diameter of the insertion portion with a simple structure and a small number of parts. There is an effect that can be done.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an entire endoscope apparatus according to an embodiment of the present invention.
FIG. 2 is an enlarged front view showing the distal end surface of the insertion portion of the endoscope according to the present embodiment.
3 is a cross-sectional view of a portion near the distal end of the insertion portion of the endoscope according to the present embodiment, which is vertically cut along a plane along the line AA in FIG.
4 is a cross-sectional view showing a portion in the vicinity of the distal end of the insertion portion, which is vertically cut along a plane along the line B-O in FIG. 2 along the longitudinal direction thereof.
FIG. 5 is a cross-sectional view showing the insertion portion across the plane along the line CC in FIG. 3;
6 is a cross-sectional view showing the insertion portion crossed by a plane along the line DD in FIG. 3; FIG.
FIG. 7 is a cross-sectional view showing the insertion portion crossed by a plane along the line EE in FIG. 3;
8 is an external view seen from the direction of arrow F in FIG. 7 at the joint between the distal end member of the insertion portion and the bending tube.
9 is a cross-sectional view showing a portion in the vicinity of the distal end of the insertion portion, which is longitudinally cut along a surface along the line O-F in FIG. 5 along the longitudinal direction thereof.
10 is a view of the positioning pin at the distal end of the insertion portion as seen from the direction of arrow G in FIG. 9;
FIG. 11 is an exploded perspective view showing a tip part of the insertion portion.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Endoscope 2 ... Insertion part 3 ... Operation part 4 ... Universal cable 5 ... Light guide connector 6 ... Camera cable 7 ... Camera connector 8 ... Tip part 9 ... Curved part 10 ... Hard part 11 ... Grip 21 ... Illumination window 22 ... light guide 23 ... solid-state imaging device 26 ... objective lens system 27 ... imaging part 28 ... imaging unit 29 ... tip body 33 ... electronic circuit board 34 ... imaging cable 35 ... tip frame 36 ... tip cylindrical member 36 ... cylindrical member

Claims

In an endoscope provided with a solid-state image sensor at the distal end of the insertion portion,
The distal end of the insertion portion includes a distal end portion main body that holds a solid-state imaging device, a distal end frame that is assembled to the distal end portion main body, and an exterior distal end cylindrical member that is disposed outside the distal end frame. The tip tube member is made of a substantially cylindrical metal part, the tip body is disposed inside the tip frame, and the tip body is made of an electrically insulating material. Endoscope characterized by.

The endoscope according to claim 1 , wherein when the distal end frame and the distal end main body are combined, a light guide is disposed in a space formed between the members.