JP3631056B2

JP3631056B2 - Light wave reflection tomography observation device

Info

Publication number: JP3631056B2
Application number: JP23988299A
Authority: JP
Inventors: 直弘丹野
Original assignee: Japan Science and Technology Agency; National Institute of Japan Science and Technology Agency
Current assignee: Japan Science and Technology Agency; National Institute of Japan Science and Technology Agency
Priority date: 1999-08-26
Filing date: 1999-08-26
Publication date: 2005-03-23
Anticipated expiration: 2019-08-26
Also published as: JP2001066245A

Description

【０００１】
【発明の属する技術分野】
本発明は、光波反射断層像観測装置に係り、例えば、高光散乱媒体である生体などの内部に分布する微小物体などを散乱中心とする、散乱ポテンシャルからの後方散乱光波を検出し、高光散乱媒体からの反射光波であってもコヒーレンスが残存することを利用し、低コヒーレント光のコヒーレント長の短さを利用した干渉計測手段で散乱位置情報と反射振幅情報を取得するものであり、これらの検出を物体内部の走査により、１次元あるいは２次元さらには３次元の多次元画像情報を構築する技術に関し、例えば、生体などの高光散乱媒体の断層像を遠隔装置にて容易に観測できるようにした光波反射断層像観測装置に関するものである。
【０００２】
【従来の技術】
高光散乱媒体である生体の反射断層像を得る試みは、低コヒーレント光を用いて干渉計を構成することから始まる。
【０００３】
図１２及び図１３を例示して、従来技術を説明する。
【０００４】
図１２は従来の光波反射像測定装置の構成図である。この装置は本願発明者によって特公平６−３５９４６号として既に特許されたものである。
【０００５】
この装置は、低コヒーレント（部分的コヒーレントとも表現する）光源５１からの光束を直ちにマイケルソン干渉計に導入し、ビームスプリッター５３により光束を分割し、一方を参照光として周波数シフトを与え、物体奥行き情報の走査を兼ねる可動反射鏡５２により反射して光検出素子５５に入射させる。
【０００６】
また、他方の透過光は物体照射光とし、物体５４の深部に至る屈折率の異なる散乱体の層から散乱反射され、物体反射光波となり、ビームスプリッター５３により前記参照光と合波干渉され光検出素子５５よりビート信号が検出されるものである。その照射光と物体５４の位置関係を変化走査して、検出された電気信号はフィルターや増幅信号処理部５６ａを経て、コンピュータ５６で記録・画像化されて反射断層像が得られる。
【０００７】
他方、本原理に基づく構成の光路に光ファイバーを配置して、外部振動対策や取り扱いを簡便化したのが図１３であり、特表平６−５１１３１２号公報として開示されている。なお、図１２と同じ部分については同じ符号を付してそれらの説明は省略する。
【０００８】
これによれば、光源５１からの光束はファイバー６１内を導波し、分岐合波回路５７を経て、一方はファイバー６１の出射端よりプローブ装置５８の凸レンズ５８ａにて集光され、物体５４より物体反射光波が形成される。他方の光束はピエゾ振動位相シフター５９により周波数シフトが与えられ、可動反射鏡６０により反射されて参照光を形成し、分岐合波回路５７を経て前記物体反射光波と合波干渉されて光検出素子５５に入射し、上記した先行技術と同様にして反射断層像が観測される。
【０００９】
しかしながら、従来の干渉測定法では、何れも光走査する際に、１ビームのみをプローブ光として物体に照射し物体反射光波も散乱ポテンシャルからの近軸反射光線のみを捕捉することで、ヘテロダイン検波を行っており、物体照射光束の横断面積の直径で分解能が決まるので、空間コヒーレンスを必要とし、結像関係の像情報は散逸していた。
【００１０】
【発明が解決しようとする課題】
上記した従来の方法で共通することは、いずれも参照光路と物体反射光路とが異なる経路を経て合波干渉されていることであり、また、前述のように結像関係の回折反射光の像情報は無視していることである。
【００１１】
特に、物体へのプローブの役割を果たす、図１３の光ファイバー６１を用いる場合は遠隔計測には向いているが、両光路とも長距離となるため、外部環境の温度によって光路長が変化し、実用化においては温度補償技術を必要としている。
【００１２】
特に、コヒーレント長が数ミクロンと短い高空間分解能の装置を構成する場合には、広帯域のスペクトルに対する分散も影響してきて重大な位相障害となる。
【００１３】
後者の先行技術には光ファイバー束を用いて、照射ビームを走査する方法も開示されているが、ファイバー束の各ファイバー光路長のサブミクロン程度の伸び縮みによる位相擾乱が生じ、ビート信号の著しい低減を招くため、実用は至難であり、また、光ファイバーには単一モードファイバが使用されるのが一般的であるので、いずれも鉛直断面画像の伝送は不可能である。
【００１４】
その結果、その画素信号は軽微なものとなり、著しくＳＮが悪く、物体深部の情報を得て画像化するのが困難であった。また、従来は物体深部からの反射光波が偏光解消し、ヘテロダイン検波ではその偏光選択性から参照光波と同一の偏光ベクトルを有する成分のみしか検出できないため、物体深部からの情報は検出が困難であった。特に、物体表面からの直線偏光成分の反射光波が著しく強いため、光検出器が飽和し、弱いヘテロダインビート信号は埋没され、著しくＳＮが悪化し画像信号の検出は困難であった。
【００１５】
本発明は、上記問題点を解決するために、物体照射直前において略平行光束の断面分布を保持して前駆参照光波を予め生成し、この前駆参照光波を物体反射光波より時間にして、例えば、０．１ｎｓｅｃ程度先行させて、同時に同一光路を伝搬させ、経路内の分散や位相擾乱をその鉛直断面分布にわたり両光波に同一の位相変化を与え、断面分布の各画素ごとに光検出する。ヘテロダイン光検出法は、２乗検波特性を有し両者の光電界の共役な波面同士が干渉し出力される。
【００１６】
その結果、互いの同相の位相変化は相殺されて検出されず、途中光路の擾乱や分散はヘテロダイン検波出力に影響しないで検出できるように構成でき、さらに、物体深部の反射光波ほど偏光解消することに注目し、光ヘテロダイン検出特性を利用して物体深部信号をより効率良く検出するように構成し、さらには散乱ポテンシャルからの回折散乱反射光波をも捕捉し、空間コヒーレンスを考慮した合波干渉信号を利用して、広ダイナミックレンジでさらに高ＳＮで反射信号を走査抽出して、生体などの深部断層の静的あるいは動的構造を検知し、多次元画像化して観測可能とする光波反射像観測装置を提供することを目的とする。
【００１７】
【課題を解決するための手段】
本発明は、上記目的を達成するため、低コヒーレント光源からの光波を略平行光束とし、その断面分布の波面を保持して被検体直前にて２分割し、一方を照射光波とし、この照射光波による物体深部からの回折散乱光による鉛直断面像を有する物体反射光波を得て、他方をこの物体反射光波に対し相対的に前駆する参照光波となす手段と、この前駆参照光波と前記物体反射光波とが光検出器に至る長光路の擾乱や分散による位相変化を受けることにおいて、相互に共役な波面との後述の合成干渉検出法により前記位相変化を相殺できる同一光路と、前記前駆参照光波を連続的に遅延し前記物体反射光波と前記分割波面に対応して時空間コヒーレント長以内で合波干渉する手段と、前記前駆参照光波と前記物体反射光波間に相対的周波数シフトを与える手段と、前記物体反射光波が鉛直断面像を形成するに際し、その画素相当の部分波に対し、前記合波干渉光の画素を走査抽出する手段と、この抽出光を光電変換することにより前記周波数シフトに相当するヘテロダインビート周波数を検出する手段と、ビート信号と遅延手段とにより前記鉛直断面分布像の各画素に対し物体奥行きの反射断層像の構成要素とする振幅と位置情報を得て画素信号とする手段とを、具備して光波反射断層像を観測できるようにしたものである。
【００１８】
また、光源からの光束を直線偏光とし、前記前駆参照光波は同一直線偏光成分とし、前記物体反射光波は物体表面近傍からの反射成分はこの直線偏光成分が多く、他方物体深部に至るほど高光散乱媒体である生体などにおいては偏光解消したこの直線偏光に直交する成分が多くなることにおいて、前記合波干渉光に対し、この直線偏光に直交する成分を多く透過させ、この直線偏光成分の前駆参照光波と物体表面からの物体反射光波成分とを少なく透過させるように所定の偏光角にて偏光板を配置し、物体表面の強い反射光波を低減させ物体深部の弱い反射情報を捕捉できる手段とを、具備して光波反射断層像を観測できるようにしたものである。
【００１９】
さらには、非測定物体が動的散乱ポテンシャル部分を含みドップラーシフト周波数となる物体反射光波を生成する場合に、前記鉛直断面分布を有する合波干渉光の光検出手段から出力されるそのドップラーシフトビート成分を検出して複数の各空間分割成分信号を合成することにより、前記動的散乱ポテンシャルからの散乱光波の振幅情報を検出する手段と、前記ドップラーシフトビート成分周波数より動的散乱ポテンシャルの移動速度及び方向を前記鉛直断面像と奥行き反射像の３次元画素ごとに計算し表示する手段と、を具備して生体深部の動的構造なども可視化できるようにしたものである。
【００２０】
また、高速化を図るために、被測定検体の所望の領域に亘り深部情報を検知し、各画素毎の各再生信号を記録蓄積し信号処理を施し多次元深部断層像として表示するコンピュータと表示器と、を具備し光波散乱断層像観測装置を構成したことに特徴がある。
【００２１】
【発明の実施の形態】
以下、本発明の実施形態について詳細に説明する。
【００２２】
図１は本発明の実施例を示す遅延参照光ヘテロダイン検波光反射断層像観測装置の構成図である。
【００２３】
この図に示すように、低コヒーレント光源１からの光束をコンデンサレンズ系２で収束光３とし、半透明反射鏡４を介して空間フィルター５の開口を通過させ凸レンズ６により略平行光束とする。
【００２４】
被測定検体（単に、被検体又は物体という場合もある）９の近傍に配置した平面半透明反射鏡６ａにより、略平行光束を波面を保持して反射させ前駆参照光波７を発生させる。平面半透明反射鏡６ａからの透過光は対物レンズ８により集光して被測定検体９に照射する。
【００２５】
被測定検体９の深部からの物体反射光波１０は対物レンズ８で捕捉され、前駆参照光波７と同一の光路を経て、最終的に光検出器１９に至る。
【００２６】
本原理による物体反射光波面と前駆参照光波面の形成法を図２に示す。ここで、図２（１）は物体照射光が凸レンズによる収束光の場合、図２（２）は略平行光の場合をそれぞれ示している。
【００２７】
図２（１）、図２（２）において、光源からの波面は平面半透明反射鏡６ａで分割され、反射光波面は前駆参照光波７となる。他方、透過光は対物レンズ８で収束され、物体照射光となる。被測定検体９の深層にある細胞などの散乱ポテンシャル９ａからの物体反射光波１０は対物レンズ８で捕捉される。
【００２８】
対物レンズ８は、この時前焦点を通る光軸方向の回折散乱反射成分のみを選択的に捕捉する作用と空間フィルター５の作用により周辺の余分な散乱光を除去し、所望の位置の散乱ポテンシャル９ａのみの画素情報を取得できることになる。これは、前焦点前後の光軸に沿った断面分布をもつ反射光波成分のみを捕捉するために共焦点系を構成しているのであり、通常の共焦点顕微鏡のように焦点のみの狭い一点の画素信号を捕捉するための構成でない。ここでは、通常の共焦点顕微鏡と基本的に異なる作用を利用し、物体深層の断面分布９ｂの反射画像を検知していることが重要である。
【００２９】
このように、分岐された各光波は、一方は物体反射光波、他方は前駆参照光波となるが同一光路を伝搬する。この時、前駆参照光波７と被測定検体９からの物体反射光波１０の光路差は前述のように数ｃｍと離れておらず、時間差にして、０．１ｎｓｅｃ程度に過ぎないので、前駆参照光波７と物体反射光波１０の両者は同一光路でほぼ同一の擾乱や分散による位相変移を経験する。
【００３０】
各光波は、図１に示すように凸レンズ１１により平行光束１２ａを成し、マイケルソン型干渉計１０１に入射する。そして、半透明反射鏡１３により各光波の一部は反射され反射鏡１４で反射され再度往復光１２ｂとなる。
【００３１】
一方、透過光は可動反射鏡１５ａで反射して往復光１２ｃとなる。この時、往復光１２ｂに対し、往復光１２ｃを相対的に遅らせる。すなわち、半透明反射鏡１３から可動反射鏡１５ａまでの光路長を長く取り、図３に示すように両者の光電界を重畳させるようにする。
【００３２】
図３（ａ）を往復光１２ｂとすると図３（ｂ）が遅延させた往復光１２ｃである。前駆させた反射参照光波が遅延により反射物体光波と合波して、図１に示す合波光１２ｄを構成する。さらに、可動反射鏡１５ａを微細に移動し遅延参照光を物体反射光波と順次重ねていく。なお、１５ｂは可動反射鏡制御台、１７ｂはガルバノミラー制御台である。
【００３３】
物体反射光波は深部反射光波ほど遅れて反射して来る成分を有しているので、所望の深部反射光波位置まで、遅延反射光波を移動して重ねる。その結果、物体反射光波面と前駆参照光波面が合波重畳されて光検出器１９に入射され、前記各波面を有する各画素ごとのビート信号が検出される。ここで、遅延参照光電界Ｅｒ（ｘ，ｙ，ｚ）と反射物体光電界Ｅｓ（ｘ，ｙ，ｚ）を次式として表すことができる。
【００３４】
【数１】

【００３５】
【数２】

ここで、ｆは光周波数、ｆ_bは可動反射鏡１５ａの移動に基づくドップラー周波数、ｄ_r，ｄ_Sはそれぞれの往復光路長、ｚは被測定検体９の表面からの深部距離でｘ，ｙ面は深部断層面位置座標、Φ（Ｌ）は前述の同一光路で各光束が経る位相変移の総和である。
【００３６】
合波光１２ｄは、凸レンズ１６により集光され、ガルバノミラー１７ａに焦点を結ぶ。反射光波は発散光となるために、開口スリット１８に一画素相当分の光束１２ｅを入射するようにして、ガルバノミラー１７ａを適宜傾斜して深部断層面のｘ−ｙ位置を走査する。開口スリット１８からの通過光は光検出器１９により２乗検波される。この時、光検出器１９からの出力電気信号Ｉ（ｘ，ｙ，ｚ）は次式となる。
【００３７】
【数３】

ここで、Δｆは光源１の周波数幅、Ｇ（ｆ）はその周波数分布関数を表し、ここではガウス分布を仮定した。〔ＤＣｔｅｒｍｓ〕は背景雑音となる直流成分を表す。τ＝（ｄ_r−ｄ_S）／ｃで前記の遅延時間を表す。
【００３８】
上記式（３）より、ガウス関数がビート周波数ｆａで変調を受け、そのピークの位置が光波反射物体の座標ｚを表すことが分かる。この時、前記位相項Φ（Ｌ）は電界の共役との積で相殺されて、出力に影響を及ぼさない。その結果、光路途中の位相擾乱は出力の変動を招かないので、光路の歪みの補償回路などを必要とせずに安定した出力信号を得ることができる。
【００３９】
１画素の信号に対して、可動反射鏡１５ａを移動して得られる被測定検体９の奥行き信号が反射物体の深層の散乱ポテンシャルの構造情報となる。可動反射鏡１５ａを傾斜走査して画素ごとに深層の信号を得て、２次元断層像が構成される。
【００４０】
可動反射鏡１５ａの制御と送り信号は制御器２０ａにより行い、ガルバノミラー１７ａの制御は制御器２０ｂで行う。光検出器１９からの出力信号は、ビート周波数を選別するフィルター及び増幅器２０ｃで信号を信号処理装置（コンピュータ）２０に送り、記録を蓄積し適当な画像処理を経て、多次元的に断層像を表示する。鉛直断面像を観測したい場合には、可動反射鏡１５ａを被測定検体９の深層の所の位置に対応させ、ガルバノミラー１７ａをｘ−ｙ面で走査して、観測することができる。
【００４１】
図４は本発明の他の実施例を示す偏波制御ヘテロダイン検波光反射断層像観測装置の構成図である。なお、上記した実施例と同じ部分には同じ符号を付してその説明は省略する。
【００４２】
この実施例では、低コヒーレント光源のスペクトルを制御してコヒーレント長を可変とし、ｚ軸上の空間分解能を任意に設定する。
【００４３】
例えば、ヨウ素ランプを光源として、波長域を０．５〜１．３μｍとすると、空間分解能０．４５μｍを得る。図４に示すように、所定の帯域を透過する色ガラスや誘電体蒸着フィルター等をカラーフィルター１ａに配置して実現する。さらに、光束の偏光特性を直線偏光として使用するために、直線偏光フィルター２１ａを図のように配置する。
【００４４】
したがって、物体照射光波と前駆参照光波７を、例えば、紙面に平行なｐ−偏光とする。被測定検体９に照射された光束は、屈折率境界で後方散乱を生じると同時に、その散乱光波は深部からの散乱ほど偏光解消となり、入射直線偏光成分と同一の偏光特性を持たなくなることが知られている。
【００４５】
それ故、深部からの後方散乱光ほどｓ−偏光成分が増大することと、ｐ−偏光成分は物体表面からの不用な反射が著しいことに注目し、ｓ−偏光成分の反射物体光電界Ｅｓを検出する方法を見出した。
【００４６】
即ち、前記遅延参照光波を作る図４に示すマイケルソン干渉計１０１において、遅延反射用の可動反射鏡１５ａの直前に四分の一波長板２１ｂを配置し、反射遅延参照光波をｓ−偏光成分として、ｓ−偏光成分の反射物体光電界Ｅｓと合波して干渉信号を得るものである。
【００４７】
一般に生体などの高光散乱媒質では、深部からの信号反射光波は著しく減衰するが、この方法により偏光解消した成分を遅延参照光波の偏光回転でヘテロダイン検出することにより補填できることになる。
【００４８】
さらには、四分の一波長板２１ｂの代わりに可変偏光移相器等を配置すると、ｐ−偏光、ｓ−偏光や円偏光成分を適宜案分して、被測定媒質の複屈折性を考慮するなどして最適な信号特性を得ることも出来る。図４におけるその他の動作は図１の実施例と同様であるので省略する。
【００４９】
次に、光検出器に２次元アレイセンサーを用いた光波反射像観測装置を図５に示す。
【００５０】
ここでは、合波光１２ｄを集光し、迷光を空間フィルター２３で除去した後、レンズ１６ａで反射映像を光アレイセンサー２４の面に結像して、各干渉画素をヘテロダイン検出するものである。
【００５１】
所望の画素数に相当する光検出素子数を備えた光アレイセンサー２４は、画素毎にヘテロダイン検波して映像信号を検出する。各検出器からの信号は、信号処理装置（コンピュータ）２０のビート周波数のバンドパスフィルターを経てロックインアンプで増幅集積し、ＤＣ出力とし、ディスプレイに画像表示などをして、被測定検体９内部の多次元断層像の観測を実現するものである。
【００５２】
この実施例では、図１のガルバノミラー１７ａが不要となり、即ち画素信号の検出に光走査をすることなく、瞬時に画像信号を検出することができ、高速映像化が可能となる。
【００５３】
また、被測定検体９の深部鉛直断面の反射像を瞬時に映像化でき、深部検出位置を可動反射鏡１５ａを、例えばｚ−軸上で１０μｍ毎に鉛直断面映像信号を記録蓄積して、３次元断層像を任意の切り口で再生して映像化できるものである。
【００５４】
また、この実施例では対物レンズに相当する集光レンズ８を可動台２２により、光軸方向に前後して、適宜集光点位置を可変にする機構も備え、照射光波強度と反射光波強度を最適化できるという特徴も備えている。
【００５５】
次に、被測定検体９への光路に光バンドルファイバーをプローブとして用いた光バンドルファイバー付光反射断層像観測装置の構成例を図６に示す。
【００５６】
これは、図１における半透明反射鏡４より被測定検体９に至る光路を図６に示す光バンドルファイバー３１ｄとする方法である。
【００５７】
また、光源１からの光路にはテーパ型ファイバー３１ａを配置して、光の集光性を容易にしている。このテーパ型ファイバー３１ａからの略平行光束を凸レンズ２ｂで平行光束にして半透明反射鏡３８で反射してプローブ用光バンドルファイバー３１ｄに入射する。この光バンドルファイバー３１ｄの出射端面に半透明光反射膜６ｂを密着して作り、前駆参照光波７を発生させる。なお、３９はレンズホルダーである。
【００５８】
透過照射光は凸レンズ８ａで集光し、被測定検体９に照射する。前記前駆参照光波７と被測定検体９からの物体反射光波１０とは、バンドル内の同一のファイバーを経由して、干渉計１０１に入射して、図１における動作により、反射断層像を得る。
【００５９】
このように構成することにより、長尺のファイバーであっても、前述の位相擾乱の相殺方法により、ファイバーによる擾乱とそれによる雑音を消去出来るので、高い雑音対信号比で画素信号を得ることが可能となる。このような光バンドルファイバーのプローブ使用により、例えば、胃カメラやファイバーカテーテルとの併用により、胃壁の写真と同時に胃壁の深層の断層像を映像化することができる。
【００６０】
次に、被測定検体への光路に屈折率分布ファイバーをプローブとして用いた屈折率分布ファイバー付光反射断層像観測装置の実施例を図７に示す。
【００６１】
ここでは、光源１からの光バンドルファイバー３１ｂを通った光束を凸レンズ２ｂで結合し、光束を屈折率分布ファイバー３１ｅまたテーパ型屈折率分布ファイバー３１ｆに入射する。入射光束は屈折率分布に応じて収束分散を周期的に繰り返し出射端に至る。なお、４は半透明反射鏡である。
【００６２】
このファイバー長と先のレンズの結合を適宜選択すると、出射端からの光束を略平行に出来る。その出射端面に部分的光反射膜６ｃを密着して、略平行光束から前駆参照光波を発生させる。透過光は前記と同様に被測定検体９に入射し、物体反射光波１０を得る。
【００６３】
前記実施例の光バンドルファイバーの場合と異なり、前駆参照光波７と物体反射光波１０は屈折率分布ファイバー３１ｅ内を収束発散を繰り返して伝搬するが、屈折率分布ファイバー３１ｅ内で受ける位相擾乱は、共に同一の位相擾乱を受けるため、前記原理により、両者の位相擾乱は相殺されて干渉信号が検出できる。画素信号を検出する他の動作は、図１の実施例に基づくものであるので説明は省略する。
【００６４】
次に、被測定検体への光路に映像を撮像するＣＣＤカメラ付光反射断層像観測装置の構成例を図８に示す。
【００６５】
ここでは、前駆参照光波７と物体反射光波１０が干渉計ｌ０１に至る途中の光路に半透明反射鏡２５を配置して、反射光波を、例えば１０％ほど取り出す。その反射光波は強い前駆参照光波７を含み、前駆参照光波７は映像ではないので、直線偏光フィルタ２１ｃを配置して、偏光面を直交して減衰させて影響を取り除く。
【００６６】
物体反射光波１０は前記したように偏光解消によって、直交した直線偏光フィルタ２１ｃを透過する反射映像成分を有するので、結像レンズ系２６によってＣＣＤ検出器２７に結像される。このＣＣＤ検出器２７では、被測定検体９の照射光内の顕微鏡像が対物レンズに相当する集光レンズ８と結像レンズ系２６との作用で観測できる。
【００６７】
この実施例では、断層像観測面の映像を予めこのＣＣＤ検出器２７によって観測しつつ、所望の位置の断層像を観測できることに特徴がある。図６及び図７の実施例における光バンドルファイバーや屈折率分布ファイバーにおいても、各実施例の構成では、断層像観測面の映像が伝送でき、本実施例を組み込んだ装置も構成可能である。
【００６８】
次に、被測定検体への側面照射付光反射断層像観測装置の構成例を図９に示す。ここでは、光源１からの光束を一旦集光し、その発散光の一部を断層像観測用照射光２８ａとなし、凸レンズ６を経て物体反射光波１０を形成する。
【００６９】
他方、レンズ６の周辺部の光束２８ｂは、コーン型の透明プラスチックより成る光導波体２９に導かれ、筒状内を全反射を繰り返し導波して切り込まれた先端部より、被測定検体９の表面に側面より照射される側面照射光３０となる。
【００７０】
生体などの半透明な物質を観測する場合、正面照射より側面照射の方が表面の強い反射光波を避けて映像化できることが知られており、この実施例では強い反射光波が生じる垂直入射の照射を低減し、深層に至る映像化が高効率にできる特徴がある。
【００７１】
次に、被測定検体への光ファイバー導波側面照射付光反射断層像観測装置の構成例を図１０に示す。
【００７２】
ここでは、光源からの光束を半透明反射鏡４で分割して、図示するように反射光波を凸レンズ３２で集光して円周分布型ファイバー束３１ｃに導波して図９の構成例と同様にコーン型光導波体３３に導波し、側面照射光を形成するものである。
【００７３】
この実施例ではＣＣＤカメラ装置１０３とコーン型光導波体３３を含むプローブ装置１０４等を一体化して観測に至便な装置とできる特徴がある。干渉系１０１への光束の導入は、光バンドルファイバー３１ｂや屈折率分布ファイバーなどを用いて、プローブ装置１０４等を遠隔操作ができるように離して構成することもできる。
【００７４】
次に、ＣＣＤカメラ映像用光源を別途備えた２光源方式光反射断層像観測装置の構成例を図１１に示す。
【００７５】
ここでは、ＣＣＤカメラ映像用光源３６には、例えばハロゲンランプを備え、光源の熱線を除去するため色ガラスフィルター３６ａを配置し、光束を光バンドルファイバー３１ｄを用いてプローブ装置１０４に導入して、前記実施例と同様に側面照射光を形成する。なお、３７は凸レンズである。
【００７６】
他方、低コヒーレント光源１としては、ヨウ素ランプの代りにスーパールミネッセントダイオードの低コヒーレント光を用いて、前記実施例と同様に動作して断層像を得る。
【００７７】
この実施例では、光源をそれぞれ独立に用意することで、光源のスペクトル成分を可変にして、例えば、ＣＣＤカメラ映像用光源３６のスペクトル成分は昼光色となし、低コヒーレント光源１には生体などを透過しやすい赤外域のスペクトル成分を多くするなどして、高効率でそれぞれの映像化を達成できる特徴がある。
【００７８】
この実施例のいずれの構成においても、被測定検体が動的散乱ポテンシャル部分を含みドップラーシフト周波数となる物体反射光波を生成する場合、前記鉛直断面分布を有する合波干渉光の光検出器から出力されるそのドップラーシフトビート成分を電気的フィルターを通過して検出して複数の各空間画素成分信号を合成することにより、前記動的散乱ポテンシャルからの散乱光波の振幅情報を抽出し、前記ドップラーシフトビート成分周波数より動的散乱ポテンシャルの移動速度及び方向を前記鉛直断面像と奥行き反射像の３次元画素ごとに計算し表示するコンピュータを具備し、例えば生体深部の血流分布などの動的構造を可視化できるようにしたことを特徴とする光波反射断層像観測装置が構成できる。
【００７９】
前記各実施例で示した各構成を本発明の趣旨を違えることなく、適宜組み合わせを変化させても本発明の範囲内にあることは明らかである。
【００８０】
また、本発明は、上記実施例に限定されるものではなく、本発明の趣旨に基づき種々の変形や単独使用も可能であり、それらを本発明の範囲から排除するものではない。
【００８１】
【発明の効果】
以上、詳細に説明した様に、本発明は、低コヒーレント光源からの光波を略平行光束とし、その断面分布の波面を保持して被検体直前にて２分割し、一方を照射光波とし、この照射光波による物体深部からの回折散乱光による鉛直断面像を有する物体反射光波を得て、他方をこの物体反射光波に対し相対的に前駆する参照光波となす手段と、この前駆参照光波とこの物体反射光波とが光検出器に至る長光路の擾乱や分散による位相変化を受けることに際し相互に共役な波面との後述の合成干渉検出法により前記位相変化を相殺できる同一光路と、前記前駆参照光波を連続的に遅延し前記物体反射光波と前記分割波面に対応して時空間コヒーレント長以内で合波干渉する手段と、前記前駆参照光波と前記物体反射光波間に相対的周波数シフトを与える手段と、この物体反射光波が鉛直断面像を形成するためにその画素相当の部分波に対し、この合波干渉光の画素を走査抽出する手段と、この抽出光を光電変換することにより、この周波数シフトに相当するヘテロダインビート周波数を検出する手段と、このビート信号とこの遅延手段により前記鉛直断面分布像の各画素に対し物体奥行きの反射断層像の構成要素となる振幅と位置情報を得て画素信号とする手段とを具備して光波反射断層像を観測できる。
【００８２】
また、光源からの光束を直線偏光とし、前記前駆参照光波は同一直線偏光成分とし、前記物体反射光波は、物体表面近傍からの反射成分は該直線偏光成分が多く、他方物体深部に至るほど高光散乱媒体である生体などにおいては偏光解消したこの直線偏光に直交する成分が多くなるため、前記合波干渉光に対し、この直線偏光に直交する成分を多く透過させ、この直線偏光成分の前駆参照光波と物体表面からの物体反射光波成分とを少なく透過させるように所定の偏光角にて偏光板を配置し、物体表面の強い反射光波を低減させ物体深部の弱い反射情報を捕捉できる手段とを具備して光波反射断層像を観測できる。
【００８３】
さらには、被測定検体が動的散乱ポテンシャル部分を含みドップラーシフト周波数となる物体反射光波を生成するにおいて、前記鉛直断面分布を有する合波干渉光の光検出手段から出力される該ドップラーシフトビート成分を検出して複数の各空間分割成分信号を合成することにより、前記動的散乱ポテンシャルからの散乱光波の振幅情報を検出する手段と、前記ドップラーシフトビート成分周波数より動的散乱ポテンシャルの移動速度および方向を前記鉛直断面像と奥行き反射像の３次元画素ごとに計算し表示する手段とを具備して生体深部の動的構造なども可視化できるようにした光波反射断層像観測装置である。
【００８４】
また、高速化を図るために、被測定検体の所望の領域に渡り深部情報を検知し、各画素毎の各再生信号を記録蓄積し、信号処理を施し多次元深部断層像として表示するコンピュータと表示器とを具備し光波散乱断層像観測装置を構成することができる。
【００８５】
以上のように、本発明によれば、生体を構成する細胞や組織などの散乱ポテンシャルからの回折散乱反射光波をも捕捉し空間コヒーレンスを考慮した合波干渉信号を利用して、広ダイナミックレンジでさらに高ＳＮで反射信号を走査抽出して、生体などの深部断層の静的あるいは動的構造を検知し多次元画像化して形態学的情報や血流分布などの医療情報や半導体をはじめとする諸材料の組織学的情報などを非侵襲、非破壊的に顕微鏡レベルの高空間分解能で観測可能とし、新規な光波反射像観測装置を提供することができる。
【図面の簡単な説明】
【図１】本発明の実施例を示す遅延参照光ヘテロダイン検波光反射断層像観測装置の構成図である。
【図２】本原理による物体反射光波面と前駆参照光波面の形成法を示す説明図であり、図２（１）は物体照射光が凸レンズによる収束光の場合、図２（２）は略平行光の場合である。
【図３】前駆参照光波を遅延させて物体反射光波と合波してヘテロダイン干渉ビート信号により物体反射信号を検出する方法と位相擾乱Φ（Ｌ）を相殺する方法の説明図である。
【図４】本発明の他の実施例を示す偏波制御ヘテロダイン検波光反射断層像煽測装置の構成図である。
【図５】光検出器に２次元アレイセンサーを用いた光波反射像観測装置の実施例図である。
【図６】光バンドルファイバーをプローブとして用いた光バンドルファイバー付光反射断層像観測装置の構成図である。
【図７】屈折率分布ファイバーをプローブとして用いた屈折率分布ファイバー付光反射断層像観測装置の構成図である。
【図８】被測定検体への光路に映像を撮像するＣＣＤカメラ付光反射断層像観測装置の構成図である。
【図９】被測定検体への側面照射付光反射断層像観測装置の構成図である。
【図１０】被測定検体への光ファイバー導波側面照射付光反射断層像観測装置の構成図である。
【図１１】ＣＣＤカメラ映像用光源を別途備えた２光源方式光反射断層像観測装置の構成図である。
【図１２】従来の光波反射像測定装置の構成図である。
【図１３】図１２の原理に基づく構成の光路に光ファイバーを配置して、外部振動対策や取り扱いを簡便化した構成図である。
【符号の説明】
１低コヒーレント光源
１ａカラーフィルター
２コンデンサレンズ系
２ｂ，６，８ａ，１１，１６，３２，３７凸レンズ
３収束光
４，１３，２５，３８半透明反射鏡
５，２３空間フィルター
６ａ平面半透明反射鏡
６ｂ半透明光反射膜
６ｃ部分的光反射膜
７前駆参照光波
８対物レンズ
９被測定検体
９ａ散乱ポテンシャル
９ｂ断面分布
１０物体反射光波
１２ａ平行光束
１２ｂ，１２ｃ往復光
１２ｄ合波光
１２ｅ光束
１４反射鏡
１５ａ可動反射鏡
１５ｂ可動反射鏡制御台
１６ａレンズ
１７ａカルバノミラー
１７ｂガルバノミラー制御台
１８開口スリット
１９光検出器
２０信号処理装置（コンピュータ）
２０ａ，２０ｂ制御器
２０ｃフィルター及び増幅器
２１ａ，２１ｃ直線偏光フィルター
２１ｂ四分の一波長板
２２可動台
２４光アレイセンサー
２６結像レンズ系
２７ＣＣＤ検出器（ＣＣＤカメラ）
２８ａ断層像観測用照射光
２８ｂ周辺部の光束
２９光導波体
３０側面照射光
３１ａテーパ型ファイバー
３１ｂ，３１ｄ光バンドルファイバー
３１ｃ円周分布型ファイバー束
３１ｅ屈折率分布ファイバー
３１ｆテーパ型屈折率分布ファイバー
３３コーン型光導波体
３６ＣＣＤカメラ映像用光源
３６ａ色ガラスフィルター
３９レンズホルダー
１０１干渉計
１０３ＣＣＤカメラ装置
１０４プローブ装置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light wave reflection tomographic image observation apparatus, for example, with a small object distributed inside a living body or the like as a high light scattering medium as a scattering center. , Detects backscattered light waves from the scattering potential light scattering Medium Interferometer using the short coherent length of low-coherent light, utilizing the fact that coherence remains even in the reflected light wave from the body Measurer Acquire scattering position information and reflection amplitude information in stages Is, These detections relate to a technique for constructing one-dimensional, two-dimensional or three-dimensional multidimensional image information by scanning the inside of an object. High The present invention relates to a light wave reflection tomographic image observation apparatus that can easily observe a tomographic image of a light scattering medium with a remote device.
[0002]
[Prior art]
An attempt to obtain a reflected tomographic image of a living body, which is a high light scattering medium, starts with the construction of an interferometer using low coherent light.
[0003]
The prior art will be described with reference to FIGS. 12 and 13.
[0004]
FIG. 12 is a block diagram of a conventional light wave reflection image measuring apparatus. This device has already been patented by the present inventor as Japanese Patent Publication No. 6-35946.
[0005]
This apparatus immediately introduces a light beam from a low-coherent (also referred to as partially coherent) light source 51 into a Michelson interferometer, splits the light beam by a beam splitter 53, and gives a frequency shift using one as a reference light. The light is reflected by the movable reflecting mirror 52 also serving as information scanning and is incident on the light detection element 55.
[0006]
The other transmitted light is object irradiation light, which is scattered and reflected from a scatterer layer having a different refractive index that reaches the deep part of the object 54, becomes an object reflected light wave, and is combined and interfered with the reference light by the beam splitter 53 to detect light. A beat signal is detected from the element 55. The positional relationship between the irradiation light and the object 54 is changed and scanned, and the detected electrical signal passes through a filter and an amplification signal processing unit 56a, and is recorded and imaged by the computer 56 to obtain a reflected tomographic image.
[0007]
On the other hand, configuration based on this principle of FIG. 13 shows the arrangement of an optical fiber in the optical path to simplify external vibration countermeasures and handling, which is disclosed in JP-T-6-511112. In addition, the same code | symbol is attached | subjected about the same part as FIG. 12, and those description is abbreviate | omitted.
[0008]
According to this, the light beam from the light source 51 is guided in the fiber 61, passes through the branching / multiplexing circuit 57, and one is condensed by the convex lens 58 a of the probe device 58 from the emission end of the fiber 61, and from the object 54. An object reflected light wave is formed. The other light beam is frequency-shifted by a piezo vibration phase shifter 59, reflected by a movable reflecting mirror 60 to form a reference light, and is combined and interfered with the object reflected light wave via a branching and combining circuit 57 to be detected by a light detecting element. The reflected tomographic image is observed in the same manner as in the prior art described above.
[0009]
However, in any of the conventional interferometry methods, when scanning light, heterodyne detection is performed by irradiating an object with only one beam as probe light and capturing only the paraxial reflected light from the scattering potential. Since the resolution is determined by the diameter of the cross-sectional area of the object irradiation light beam, spatial coherence is required, and image-related image information is dissipated.
[0010]
[Problems to be solved by the invention]
What is common in the above conventional methods is Z This is that the reference optical path and the object reflection optical path are combined and interfered through different paths, and the image information of the diffracted reflected light in the imaging relation is ignored as described above.
[0011]
In particular, when the optical fiber 61 of FIG. 13 is used, which serves as a probe for an object, it is suitable for remote measurement. However, since both optical paths are long distances, the optical path length changes depending on the temperature of the external environment. In order to achieve this, temperature compensation technology is required.
[0012]
In particular, when a high spatial resolution apparatus having a coherent length as short as several microns is constructed, dispersion on a broadband spectrum is also affected, which becomes a serious phase obstacle.
[0013]
Although the latter prior art also discloses a method of scanning an irradiation beam using an optical fiber bundle, phase disturbance occurs due to submicron expansion and contraction of each fiber optical path length of the fiber bundle, and the beat signal is significantly reduced. Therefore, practical use is difficult, and single-mode fibers are generally used for optical fibers. Because Yes Z Even in this case, transmission of a vertical cross-sectional image is impossible.
[0014]
As a result, the pixel signal is slight, the SN is remarkably poor, and it is difficult to obtain information on the deep part of the object and image it. Conventionally, the reflected light wave from the deep part of the object is depolarized, and in heterodyne detection, the polarization is selected. sex Thus, only the component having the same polarization vector as that of the reference light wave can be detected, so that it is difficult to detect information from the deep part of the object. In particular, since the reflected light wave of the linearly polarized component from the object surface is extremely strong, the photodetector is saturated, the weak heterodyne beat signal is buried, the SN is remarkably deteriorated, and the detection of the image signal is difficult.
[0015]
In order to solve the above problems, the present invention generates a precursor reference light wave in advance while maintaining a cross-sectional distribution of a substantially parallel light beam immediately before object irradiation, This precursor reference light wave Object reflected light wave Than In time, for example, the same optical path is propagated at the same time, for example, leading about 0.1 nsec, and the same phase change is given to both light waves over the vertical cross-sectional distribution of dispersion and phase disturbance in the path, for each pixel of the cross-sectional distribution. To detect light. The heterodyne light detection method has square detection characteristics, and conjugate wavefronts of both optical electric fields interfere with each other and are output.
[0016]
As a result, phase changes in the same phase are canceled out and not detected, and disturbances and dispersions in the optical path can be detected without affecting the heterodyne detection output. In order to detect the object deep signal more efficiently by utilizing the optical heterodyne detection characteristics, it also captures the diffracted scattered reflected light wave from the scattering potential. , Using the combined interference signal considering spatial coherence, the reflected signal is scanned and extracted at a high SN with a wide dynamic range to detect the static or dynamic structure of a deep fault such as a living body, and to create a multidimensional image It is an object of the present invention to provide a light wave reflection image observation apparatus that enables observation.
[0017]
[Means for Solving the Problems]
In order to achieve the above object, the present invention makes a light wave from a low-coherent light source a substantially parallel light beam, maintains a wavefront of its cross-sectional distribution and divides it into two immediately before the subject, and sets one light as an irradiation light wave. Means for obtaining an object-reflected light wave having a vertical cross-sectional image by diffracted and scattered light from the deep part of the object, and making the other a reference light wave that is precursor relative to the object-reflected light wave, and the precursor reference light wave and the object reflected light wave Receiving the phase change due to disturbance or dispersion of the long optical path leading to the photodetector, the same optical path that can cancel the phase change by a synthetic interference detection method described later with a wavefront that is conjugate to each other, and the precursor reference light wave Means for continuously delaying and interfering with the object reflected light wave and the split wavefront within a spatio-temporal coherent length, and a relative frequency shift between the precursor reference light wave and the object reflected light wave And a means for scanning and extracting a pixel of the combined interference light with respect to a partial wave corresponding to the pixel when the object reflected light wave forms a vertical cross-sectional image, and photoelectrically converting the extracted light by photoelectric conversion. A pixel that obtains amplitude and position information as a component of a reflection tomographic image of an object depth for each pixel of the vertical cross-sectional distribution image by means for detecting a heterodyne beat frequency corresponding to a frequency shift, and a beat signal and a delay means. A signal means is provided so that a light-wave reflection tomographic image can be observed.
[0018]
The light beam from the light source is linearly polarized, the precursor reference light wave has the same linearly polarized light component, and the reflected light wave from the object has a large amount of linearly polarized light reflected from the vicinity of the object surface. In a living body such as a medium, since there are many components orthogonal to the linearly polarized light that has been depolarized, a large amount of the component orthogonal to the linearly polarized light is transmitted to the combined interference light. A polarizing plate is arranged at a predetermined polarization angle so as to transmit a light wave and an object reflected light wave component from the object surface to a small extent, and a means for reducing a strong reflected light wave on the object surface and capturing weak reflected information in the deep part of the object. , So that a light wave reflection tomographic image can be observed.
[0019]
Further, when a non-measurement object generates an object reflected light wave including a dynamic scattering potential portion and having a Doppler shift frequency, the Doppler shift beat output from the combined interference light detection means having the vertical cross-sectional distribution is provided. Means for detecting the amplitude information of the scattered light wave from the dynamic scattering potential by detecting a component and synthesizing a plurality of spatial division component signals, and the moving speed of the dynamic scattering potential from the Doppler shift beat component frequency And means for calculating and displaying the direction for each three-dimensional pixel of the vertical cross-sectional image and the depth reflection image so that the dynamic structure of the deep part of the living body can be visualized.
[0020]
In addition, in order to increase the speed, a computer and a display that detect deep information over a desired region of the sample to be measured, record and store each reproduction signal for each pixel, perform signal processing, and display it as a multidimensional deep tomographic image And a light wave scattering tomographic image observation apparatus.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
[0022]
FIG. 1 is a configuration diagram of a delayed reference beam heterodyne detection light reflection tomographic image observation apparatus showing an embodiment of the present invention.
[0023]
As shown in this figure, the light beam from the low-coherent light source 1 is made into convergent light 3 by the condenser lens system 2, passed through the opening of the spatial filter 5 through the semitransparent reflecting mirror 4, and made into a substantially parallel light beam by the convex lens 6.
[0024]
Sample to be measured (Sometimes simply referred to as a subject or object) By the flat translucent reflecting mirror 6a disposed in the vicinity of 9, a substantially parallel light beam is reflected while holding the wavefront, and the precursor reference light wave 7 is generated. The transmitted light from the flat translucent reflecting mirror 6a is condensed by the objective lens 8 and applied to the sample 9 to be measured.
[0025]
The object reflected light wave 10 from the deep part of the sample 9 to be measured is captured by the objective lens 8, and finally reaches the photodetector 19 through the same optical path as that of the precursor reference light wave 7.
[0026]
According to this principle Object reflected light A method for forming the wavefront and the precursor reference light wavefront is shown in FIG. Here, FIG. 2 (1) shows the case where the object irradiation light is convergent light by the convex lens, and FIG. 2 (2) shows the case of substantially parallel light.
[0027]
In FIG. 2 (1) and FIG. 2 (2), the wavefront from the light source is divided by the planar translucent reflecting mirror 6 a, and the reflected light wavefront becomes the precursor reference light wave 7. On the other hand, the transmitted light is converged by the objective lens 8 and becomes object irradiation light. The object reflected light wave 10 from the scattering potential 9 a such as a cell in the deep layer of the sample 9 to be measured is captured by the objective lens 8.
[0028]
The objective lens 8 is This In this case, only the diffraction scattering reflection component in the optical axis direction passing through the front focal point is selectively captured. For and The extraneous scattered light in the vicinity is removed by the action of the spatial filter 5, and pixel information of only the scattering potential 9a at a desired position can be acquired. This is because the confocal system is configured to capture only the reflected light wave component having a cross-sectional distribution along the optical axis before and after the front focal point. It is not a configuration for capturing a pixel signal. Here, it is important to detect a reflection image of the cross-sectional distribution 9b of the deep object layer by using an action basically different from that of a normal confocal microscope.
[0029]
As described above, one of the branched light waves is the object reflected light wave and the other is the precursor reference light wave, but propagates in the same optical path. At this time, precursor reference light Wave 7 And from the sample 9 to be measured Object reflection

light Wave

10 As described above, the optical path difference is not as far as several centimeters, and the time difference is only about 0.1 nsec. 7 And object reflected light wave 10 Both experience phase shift due to almost the same disturbance and dispersion in the same optical path.
[0030]
As shown in FIG. 1, each light wave forms a parallel light beam 12 a by a convex lens 11 and enters a Michelson interferometer 101. A part of each light wave is reflected by the translucent reflecting mirror 13 and reflected by the reflecting mirror 14. again It becomes the reciprocating light 12b.
[0031]
On the other hand, the transmitted light is reflected by the movable reflecting mirror 15a and becomes the reciprocating light 12c. At this time, the reciprocating light 12c is delayed relative to the reciprocating light 12b. That is, the optical path length from the translucent reflecting mirror 13 to the movable reflecting mirror 15a is made long, and the optical fields of both are superimposed as shown in FIG.
[0032]
If FIG. 3A is a round trip light 12b, FIG. 3B is a round trip light 12c delayed. Precursed reflected reference light wave Reflected object light due to delay wave And the combined light 12d shown in FIG. Further, the movable reflecting mirror 15a is moved finely, and the delayed reference light is sequentially superimposed on the object reflected light wave. In addition, 15b is a movable reflector control stand, and 17b is a galvanometer mirror control stand.
[0033]
Since the object reflected light wave has a component that reflects later as the deep reflected light wave, the delayed reflected light wave is moved and overlapped to a desired deep reflected light wave position. As a result, the object reflected light wavefront and the precursor reference light wavefront are combined and superimposed on the photodetector 19, and a beat signal for each pixel having each wavefront is detected. Here, the delayed reference light electric field Er (x, y, z) and the reflected object light electric field Es (x, y, z) can be expressed as the following equations.
[0034]
[Expression 1]

[0035]
[Expression 2]

Where f is the optical frequency and f _b Is the Doppler frequency based on the movement of the movable reflector 15a, d _r , D _S Is the reciprocal optical path length, z is the depth distance from the surface of the specimen 9 to be measured, the x and y planes are the coordinates of the deep tomographic plane position, and Φ (L) is the sum of the phase shifts that each light beam passes through the same optical path. is there.
[0036]
The combined light 12d is collected by the convex lens 16 and focused on the galvanometer mirror 17a. Since the reflected light wave becomes diverging light, the light beam 12e corresponding to one pixel is incident on the aperture slit 18, and the galvano mirror 17a is appropriately tilted to scan the xy position on the deep tomographic plane. The passing light from the aperture slit 18 is square-detected by the photodetector 19. At this time, the output electric signal I (x, y, z) from the photodetector 19 is expressed by the following equation.
[0037]
[Equation 3]

Where Δf is the light source 1 , G (f) represents its frequency distribution function, and a Gaussian distribution is assumed here. [DCterms] represents a DC component that becomes background noise. τ = (d _r -D _S ) / C represents the delay time.
[0038]
From the above equation (3), it can be seen that the Gaussian function is modulated at the beat frequency fa, and the peak position represents the coordinate z of the light wave reflecting object. At this time, the phase term Φ (L) is canceled by the product of the conjugate of the electric field and does not affect the output. As a result, phase disturbance in the middle of the optical path does not cause output fluctuations, so that a stable output signal can be obtained without the need for a compensation circuit for optical path distortion.
[0039]
The depth signal of the sample 9 to be measured obtained by moving the movable reflecting mirror 15a with respect to the signal of one pixel becomes the structure information of the scattering potential of the deep layer of the reflecting object. A two-dimensional tomographic image is formed by tilting the movable reflecting mirror 15a to obtain a deep signal for each pixel.
[0040]
Control of the movable reflector 15a and the feed signal are performed by the controller 20a, and the galvanometer mirror 17a. Control Is performed by the controller 20b. The output signal from the photodetector 19 is sent to a signal processing device (computer) 20 by a filter and an amplifier 20c for selecting a beat frequency, and recorded. The The tomogram is displayed in a multidimensional manner through accumulation and appropriate image processing. When a vertical cross-sectional image is to be observed, the movable reflecting mirror 15a can be made to correspond to the position of the deep layer of the sample 9 to be measured, and the galvanometer mirror 17a can be scanned on the xy plane for observation.
[0041]
FIG. 4 is a configuration diagram of a polarization control heterodyne detection light reflection tomographic image observation apparatus showing another embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the part same as the above-mentioned Example, and the description is abbreviate | omitted.
[0042]
In this embodiment, the spectrum of the low-coherent light source is controlled to make the coherent length variable, and the spatial resolution on the z-axis is arbitrarily set.
[0043]
For example, when an iodine lamp is used as a light source and the wavelength range is 0.5 to 1.3 μm, a spatial resolution of 0.45 μm is obtained. As shown in FIG. 4, a color glass or a dielectric deposition filter that transmits a predetermined band is arranged on the color filter 1a. Further, in order to use the polarization characteristic of the light beam as linearly polarized light, the linearly polarizing filter 21a is arranged as shown in the figure.
[0044]
Therefore, object irradiation light wave And precursor reference light wave 7 Is, for example, p-polarized light parallel to the paper surface. Sample 9 to be measured It is known that the light beam irradiated on the surface undergoes back scattering at the refractive index boundary, and at the same time, the scattered light wave is depolarized as it scatters from the deep part and does not have the same polarization characteristics as the incident linearly polarized light component.
[0045]
Therefore, paying attention to the fact that the s-polarized light component increases with backscattered light from the deep part and that the p-polarized light component is significantly reflected from the object surface. Shoot A method for detecting the object light electric field Es has been found.
[0046]
That is, the Michelson interferometer shown in FIG. 101 , The quarter-wave plate 21b is disposed immediately before the movable reflecting mirror 15a for delayed reflection, and the reflected delayed reference light wave is combined with the reflected object light electric field Es of the s-polarized component as the s-polarized component. An interference signal is obtained.
[0047]
In general, in a high light scattering medium such as a living body, a signal reflected light wave from a deep part is significantly attenuated. However, a component depolarized by this method can be compensated by heterodyne detection by polarization rotation of a delayed reference light wave.
[0048]
Furthermore, when a variable polarization phase shifter or the like is disposed instead of the quarter-wave plate 21b, p-polarized light, s-polarized light, and circularly polarized light components are appropriately distributed to take into account the birefringence of the measured medium. It is also possible to obtain optimum signal characteristics. Other operations in FIG. 4 are the same as those in the embodiment of FIG.
[0049]
Next, a light wave reflection image observation apparatus using a two-dimensional array sensor as a photodetector is shown in FIG.
[0050]
Here, the combined light 12d is collected, stray light is removed by the spatial filter 23, and then a reflected image is formed on the surface of the optical array sensor 24 by the lens 16a to detect each interference pixel heterodyne.
[0051]
The optical array sensor 24 having the number of photodetecting elements corresponding to the desired number of pixels detects a video signal by performing heterodyne detection for each pixel. The signal from each detector passes through a band pass filter of the beat frequency of the signal processing device (computer) 20 and is amplified and accumulated by a lock-in amplifier to obtain a DC output, and an image is displayed on the display. Sample 9 to be measured Realizes the observation of internal multidimensional tomographic images.
[0052]
In this embodiment, FIG.

Galvano mirror

17a becomes unnecessary, that is, an image signal can be detected instantaneously without performing optical scanning for detection of a pixel signal, and high-speed imaging can be realized.
[0053]
Also measured

Inspection

body

9 The reflection image of the deep vertical section can be instantly visualized, and the depth detection position is recorded and accumulated in the movable reflector 15a, for example, every 10 μm on the z-axis, and the three-dimensional tomographic image is arbitrarily stored. It can be played back and converted into a video.
[0054]
In this embodiment, the condenser lens 8 corresponding to the objective lens is also moved back and forth in the direction of the optical axis by the movable base 22 so as to appropriately change the focal point position. wave It also has the feature that the intensity and reflected light wave intensity can be optimized.
[0055]
Next, FIG. 6 shows a configuration example of a light reflection tomographic image observation apparatus with an optical bundle fiber using an optical bundle fiber as a probe in the optical path to the sample 9 to be measured.
[0056]
This is the translucent reflector in FIG. 4 Than Sample 9 to be measured This is a method of using the optical bundle fiber 31d shown in FIG.
[0057]
Also light source 1 A tapered fiber 31a is disposed in the optical path from the side to facilitate light condensing. The substantially parallel light beam from the tapered fiber 31a is converted into a parallel light beam by the convex lens 2b and reflected by the translucent reflecting mirror 38 to be used for the probe. light The light enters the bundle fiber 31d. this light A semi-transparent light reflecting film 6b is formed in close contact with the exit end face of the bundle fiber 31d, and the precursor reference light wave 7 is generated. Reference numeral 39 denotes a lens holder.
[0058]
The transmitted irradiation light is condensed by the convex lens 8a and irradiated to the sample 9 to be measured. The precursor reference light wave 7 and the object reflected light wave 10 from the sample 9 to be measured are incident on the interferometer 101 via the same fiber in the bundle, and a reflected tomographic image is obtained by the operation in FIG.
[0059]
With this configuration, even with a long fiber, the above-described phase disturbance canceling method can eliminate the disturbance caused by the fiber and the noise caused thereby, so that a pixel signal can be obtained with a high noise-to-signal ratio. It becomes possible. like this light By using a bundle fiber probe, a tomographic image of a deep layer of the stomach wall can be visualized simultaneously with a photograph of the stomach wall, for example, in combination with a stomach camera or a fiber catheter.
[0060]
next, Covered Measurement Inspection An embodiment of an optical reflection tomographic image observation apparatus with a refractive index distribution fiber using a refractive index distribution fiber as a probe in the optical path to the body is shown in FIG.
[0061]
Here, the light source 1 from light Bundle fiber 31 passed b The luminous flux is coupled by the convex lens 2b, and the luminous flux is incident on the refractive index distribution fiber 31e or the tapered refractive index distribution fiber 31f. The incident light beam periodically repeats the convergence dispersion according to the refractive index distribution and reaches the exit end. Reference numeral 4 denotes a translucent reflecting mirror.
[0062]
By appropriately selecting the coupling between the fiber length and the previous lens, the light flux from the emission end can be made substantially parallel. The partial light reflecting film 6c is brought into close contact with the emission end face to generate a precursor reference light wave from a substantially parallel light beam. The transmitted light is incident on the sample 9 to be measured in the same manner as described above, and an object reflected light wave 10 is obtained.
[0063]
Of the above embodiment light Unlike the bundle fiber, the precursor reference light wave 7 and the object reflected light wave 10 propagate through the refractive index distribution fiber 31e by repeated convergence and divergence. However, the phase disturbance received in the refractive index distribution fiber 31e is the same phase disturbance. Therefore, according to the above principle, the phase disturbance between the two is canceled and the interference signal can be detected. Other operations for detecting the pixel signal are based on the embodiment of FIG.
[0064]
next, Covered Measurement Inspection A configuration example of a light reflection tomographic image observation apparatus with a CCD camera that captures an image on the optical path to the body is shown in FIG.
[0065]
Here, the translucent reflecting mirror 25 is arranged on the optical path where the precursor reference light wave 7 and the object reflected light wave 10 reach the interferometer 1001, and about 10% of the reflected light wave is extracted. The reflected light wave contains a strong precursor reference light wave 7, precursor Since the reference light wave 7 is not an image, the linear polarization filter 21c is arranged to attenuate the polarization plane orthogonally to remove the influence.
[0066]
As described above, the object reflected light wave 10 has a reflected image component transmitted through the orthogonal linear polarization filter 21c by depolarization as described above, and is thus imaged on the CCD detector 27 by the imaging lens system 26. In the CCD detector 27, a microscope image in the irradiation light of the specimen 9 to be measured can be observed by the action of the condenser lens 8 corresponding to the objective lens and the imaging lens system 26.
[0067]
This embodiment is characterized in that a tomographic image at a desired position can be observed while observing an image of the tomographic image observation surface with the CCD detector 27 in advance. 6 and 7 in the embodiment light Also in the bundle fiber and the refractive index distribution fiber, in the configuration of each embodiment, the image of the tomographic image observation surface can be transmitted, and an apparatus incorporating this embodiment can also be configured.
[0068]
next, Covered Measurement Inspection FIG. 9 shows a configuration example of the light reflection tomographic image observation apparatus with side irradiation on the body. Here, the light source 1 Is once condensed, and a part of the divergent light is formed as tomographic image observation irradiation light 28 a, and the object reflected light wave 10 is formed through the convex lens 6.
[0069]
On the other hand, the light beam 28b in the peripheral portion of the lens 6 is guided to an optical waveguide 29 made of a cone-shaped transparent plastic, and is measured from the front end portion that has been cut through repeated internal reflection in the cylindrical shape. Inspection It becomes the side irradiation light 30 irradiated to the surface of the body 9 from the side.
[0070]
When observing a translucent material such as a living body, it is known that side irradiation can be imaged while avoiding strong reflected light waves on the surface rather than front irradiation. In this embodiment, normal incidence irradiation that generates strong reflected light waves is known. The feature is that it is possible to reduce the image quality and make the imaging into the deep layer highly efficient.
[0071]
next, Covered Measurement Inspection FIG. 10 shows a configuration example of a light reflection tomographic image observation apparatus with an optical fiber waveguide side-surface irradiation on the body.
[0072]
Here, the luminous flux from the light source is divided by the translucent reflecting mirror 4, and the reflected light wave is condensed by the convex lens 32 and guided to the circumferentially distributed fiber bundle 31c as shown in FIG. Similarly, the light is guided to the cone-type optical waveguide 33 to form side irradiation light.
[0073]
This embodiment is characterized in that the CCD camera device 103 and the probe device 104 including the cone type optical waveguide 33 can be integrated into a device that is convenient for observation. The introduction of the light beam into the interference system 101 is an optical bundle fiber. 31b Alternatively, the probe device 104 or the like can be configured to be remotely controlled using a refractive index distribution fiber or the like.
[0074]
Next, FIG. 11 shows a configuration example of a two-light source type light reflection tomographic image observation apparatus separately provided with a CCD camera image light source.
[0075]
Here, the CCD camera image light source 36 includes, for example, a halogen lamp, and a colored glass filter 36a is disposed to remove the heat rays of the light source, so light The bundle fiber 31d is used to introduce the probe device 104, and the side surface irradiation light is formed in the same manner as in the above embodiment. Reference numeral 37 denotes a convex lens.
[0076]
On the other hand, the low coherent light source 1 operates in the same manner as in the above embodiment using a low coherent light of a superluminescent diode instead of an iodine lamp to obtain a tomographic image.
[0077]
In this embodiment, the light source is prepared independently so that the spectral component of the light source is variable. For example, the spectral component of the CCD camera image light source 36 is daylight, and the low-coherent light source 1 transmits a living body or the like. It has the feature that each imaging can be achieved with high efficiency by increasing the spectral components in the infrared region that are easy to perform.
[0078]
In this example Z Even in this configuration, when the object to be measured generates an object reflected light wave including a dynamic scattering potential portion and having a Doppler shift frequency, the Doppler output from the combined interference light photodetector having the vertical cross-sectional distribution. By detecting the shift beat component through an electrical filter and synthesizing each of the plurality of spatial pixel component signals, the amplitude information of the scattered light wave from the dynamic scattering potential is extracted, and from the Doppler shift beat component frequency A computer that calculates and displays the moving speed and direction of the dynamic scattering potential for each of the three-dimensional pixels of the vertical cross-sectional image and the depth reflection image so as to visualize a dynamic structure such as a blood flow distribution in the deep part of the living body. An optical wave tomographic image observation apparatus characterized by the above can be configured.
[0079]
It is apparent that the configurations shown in the above embodiments are within the scope of the present invention even if the combinations are changed as appropriate without changing the spirit of the present invention.
[0080]
Further, the present invention is not limited to the above-described embodiments, and various modifications and single use are possible based on the spirit of the present invention, and they are not excluded from the scope of the present invention.
[0081]
【The invention's effect】
As described above in detail, the present invention converts the light wave from the low coherent light source into a substantially parallel light beam. , Hold the wavefront of the cross-sectional distribution and divide it into two just before the subject. , Means for obtaining an object reflected light wave having a vertical cross-sectional image by diffracted scattered light from the deep part of the object due to one of the irradiated light waves and making the other a reference light wave that is relatively precursor to the object reflected light wave; When the precursor reference light wave and the object reflected light wave are subjected to a phase change due to disturbance or dispersion of a long optical path leading to the photodetector, the same phase change can be canceled by a synthetic interference detection method described later with a wavefront conjugated to each other. An optical path, means for continuously delaying the precursor reference light wave and interfering with the object reflected light wave and the split wavefront within a spatio-temporal coherent length, and a relative relationship between the precursor reference light wave and the object reflected light wave A means for applying an optical frequency shift, a means for scanning and extracting a pixel of the combined interference light with respect to a partial wave corresponding to the pixel in order to form a vertical sectional image of the object reflected light wave, Means for detecting a heterodyne beat frequency corresponding to this frequency shift by photoelectrically converting light, and constituent elements of a reflection tomographic image of the object depth for each pixel of the vertical cross-sectional distribution image by this beat signal and this delay means The light wave reflection tomographic image can be observed by providing means for obtaining the amplitude and position information to be a pixel signal.
[0082]
The light beam from the light source is linearly polarized light, the precursor reference light wave is the same linearly polarized light component, and the object reflected light wave is , Reflection component from near object surface Is the There are many linearly polarized light components. On the other hand, in the living body, which is a high light scattering medium, the component perpendicular to the depolarized linearly polarized light increases as it reaches the deep part of the object. For The combined interference light has a predetermined polarization angle so that a large amount of the component orthogonal to the linearly polarized light is transmitted and the precursor reference light wave and the reflected object light wave component from the object surface are transmitted in a small amount. And a means for reducing the strong reflected light wave on the surface of the object and capturing weak reflected information in the deep part of the object.
[0083]
Further, when the object to be measured generates an object reflected light wave including a dynamic scattering potential portion and having a Doppler shift frequency, the Doppler shift beat component output from the light detection means of the combined interference light having the vertical section distribution And detecting the amplitude information of the scattered light wave from the dynamic scattering potential by synthesizing a plurality of spatial division component signals, and the moving speed of the dynamic scattering potential from the Doppler shift beat component frequency and A light-wave reflection tomographic image observation apparatus comprising a means for calculating and displaying the direction for each three-dimensional pixel of the vertical cross-sectional image and depth reflection image so that the dynamic structure of the deep part of the living body can be visualized.
[0084]
In order to increase the speed, a computer that detects depth information over a desired region of the sample to be measured, records and stores each reproduction signal for each pixel, performs signal processing, and displays it as a multidimensional deep tomographic image; And a light wave scattering tomographic image observation apparatus.
[0085]
As described above, according to the present invention, a circuit from a scattering potential of a cell or tissue constituting a living body is recovered. Occasionally By using a combined interference signal that captures scattered reflected light waves and considers spatial coherence, the reflected signal is scanned and extracted with a high SN with a wide dynamic range, and the static or dynamic structure of a deep fault such as a living body can be obtained. Detects and multi-dimensionally visualizes medical information such as morphological information and blood flow distribution, and histological information of various materials including semiconductors in a non-invasive and non-destructive manner with high spatial resolution at the microscope level Thus, a novel light wave reflection image observation apparatus can be provided.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a delayed reference light heterodyne detection light reflection tomographic image observation apparatus showing an embodiment of the present invention.
FIG. 2 is an explanatory diagram showing a method of forming an object reflected light wavefront and a precursor reference light wavefront according to the present principle. FIG. 2 (1) is a case where the object irradiation light is a convergent light by a convex lens, and FIG. This is the case of parallel light.
FIG. 3 is an explanatory diagram of a method of delaying a precursor reference light wave and combining it with an object reflected light wave to detect an object reflected signal by a heterodyne interference beat signal and a method of canceling out phase disturbance Φ (L).
FIG. 4 is a configuration diagram of a polarization control heterodyne detection optical reflection tomographic image measuring apparatus showing another embodiment of the present invention.
FIG. 5 is a diagram illustrating an embodiment of a light wave reflection image observation apparatus using a two-dimensional array sensor as a photodetector.
FIG. 6 shows light using an optical bundle fiber as a probe. Ba It is a block diagram of a light reflection tomographic image observation apparatus with a handle fiber.
FIG. 7 is a configuration diagram of a light reflection tomographic image observation apparatus with a refractive index distribution fiber using a refractive index distribution fiber as a probe.
[Fig. 8] Covered Measurement Inspection It is a block diagram of the light reflection tomographic image observation apparatus with a CCD camera which images an image on the optical path to the body.
FIG. 9 Covered Measurement Inspection It is a block diagram of the light reflection tomographic image observation apparatus with side irradiation to a body.
FIG. 10 Covered Measurement Inspection It is a block diagram of the optical reflection tomogram observation apparatus with an optical fiber waveguide side surface irradiation to a body.
FIG. 11 is a configuration diagram of a two-light-source light reflection tomographic image observation apparatus separately provided with a CCD camera image light source.
FIG. 12 is a configuration diagram of a conventional lightwave reflection image measuring apparatus.
13 is a configuration based on the principle of FIG. of It is the block diagram which arrange | positioned the optical fiber in the optical path and simplified the countermeasure against external vibration and handling.
[Explanation of symbols]
1 Low coherent light source
1a Color filter
2 Condenser lens system
2b, 6, 8a, 11, 16, 32, 37 Convex lens
3 convergent light
4, 13, 25, 38 Translucent reflector
5,23 Spatial filter
6a Flat translucent reflector
6b Translucent light reflecting film
6c Partial light reflection film
7 Precursor reference light wave
8 Objective lens
9 Sample to be measured
9a Scattering potential
9b Cross-section distribution
10 Object reflected light wave
12a Parallel light flux
12b, 12c round-trip light
12d combined light
12e luminous flux
14 Reflector
15a Movable reflector
15b Movable reflector control stand
16a lens
17a Carbanomirror
17b Galvano mirror control stand
18 Opening slit
19 Photodetector
20 Signal processing device (computer)
20a, 20b controller
20c Filter and amplifier
21a, 21c linear polarizing filter
21b Quarter-wave plate
22 Movable stand
24 Optical array sensor
26 Imaging lens system
27 CCD detector (CCD camera)
28a Irradiation light for tomographic image observation
28b Luminous flux at the periphery
29 Optical waveguide
30 Side-illuminated light
31a Tapered fiber
31b, 31d light Bundle fiber
31c Circumferentially distributed fiber bundle
31e Refractive index distribution fiber
31f Tapered gradient index fiber
33 Cone-type optical waveguide
36 Light source for CCD camera image
36a color glass filter
39 Lens holder
101 Interferometer
103 CCD camera device
104 Probe device

Claims

(A) The light wave from the low-coherent light source is made into a substantially parallel light beam , the wavefront of the cross-sectional distribution is maintained and divided into two immediately before the subject , one is set as the irradiation light wave, and the other is relatively relative to the irradiation light wave Means to provide a reference light wave to be precursor ;
(B) means for obtaining an object reflected light wave having a vertical cross-sectional image from the deep part of the object by the irradiation light wave;
(C) the Upon precursor reference light wave and said object reflected light waves undergoes a phase change due to disturbances or dispersion of the long optical path to the light detector, offsetting the phase change by combining interference detection methods and mutually conjugate wavefront With the same optical path
( D ) means for continuously delaying the precursor reference light wave to provide a relative frequency shift between the precursor reference light wave and the object reflected light wave;
(E) means for combining and interfering with the object-reflected light wave and the wavefronts conjugate to each other ;
( F ) means for scanning and extracting a part of the combined interference light with respect to the partial wave corresponding to the pixel so that the object reflected light wave forms a vertical cross-sectional image;
( G ) means for detecting a heterodyne beat frequency corresponding to a frequency shift by photoelectrically converting the extracted light;
( H ) means for obtaining a depth direction pixel signal by obtaining amplitude and position information as components of a reflection tomographic image of the object depth for each pixel of the vertical cross-sectional distribution image by the beat signal and the delay means;
A light wave reflection tomographic image observation apparatus comprising:

In the light wave reflected tomographic image observing apparatus according to claim 1, wherein arranged convex lens system shall be the substantially parallel illumination light waves light waves from the low coherent light source, and the substantially parallel light flux is arranged in proximity to the object plane Reflected by a transflective mirror to generate the precursor reference light wave, condensing the transmitted light of the planar transflective mirror with an objective lens to be irradiated light, and reflected light wave based on a scattering potential at a predetermined position in the deep part of the object wherein substantially a parallel beam object reflected light waves to capture a vertical sectional distribution image to the optical axis at the objective lens, the semitransparent reflecting mirror that the said precursor reference light wave and said object reflected light waves allowed propagating a coaxial optical path, the lens system , interferometer and through the beam scanning system to form the same optical path leading to the photodetector, the progenitor reference light wave with giving a frequency shift, the object reflected light waves and coupling wave interference causes delays movable to successive delays Reflection Place a Michelson interferometer having the place which have been multiplexed substantially determine the condenser lens system and the galvanometer mirror and the pixel area extracting unit that extracts a partial interference from parallel light wave opening, the cross-sectional distribution image Scanning the extraction unit over the entire surface, for each pixel of the vertical cross-sectional image by scanning the cross-sectional distribution, the positional information of the scattering potential is converted from the scanning distance of the delay movable reflector, based on the reference light wave, and said photodetector for photoelectrically converting portion interference waves the extracted, the reflection position information and amplitude information of the reflected light waves from the deep scattering potential by detecting a heterodyne beat component output from the photodetector the resulting light wave reflected tomographic image observing apparatus according to claim and Turkey to form a pixel signal of the tomographic image.

3. The light wave reflection tomogram observation apparatus according to claim 2, wherein means for recording and storing the pixel signal of the scattered light wave amplitude and the scattering position information from each of the scattering potentials and displaying the multidimensional tomogram after arithmetic processing is provided. An apparatus for observing a light wave reflection tomogram, comprising:

3. The light wave reflection tomogram observation apparatus according to claim 2, further comprising a spatial filter that selectively captures an object reflection light wave that passes through one front focal point of the convex lens.

In the light wave reflected tomographic image observing apparatus according to claim 2, the distance of the spectra of the low coherent light source is arranged a color filter changes, reflecting distribution image according to pre-SL was member reflected light waves by changing thereby the coherence length of the time domain A light-wave reflection tomography observation apparatus characterized by controlling the resolution.

3. The light wave reflection tomographic image observation apparatus according to claim 2, wherein the light beam from the low coherent light source is linearly polarized light, the precursor reference light wave is the same linearly polarized light component, and the object reflected light wave is reflected from the vicinity of the object surface. In the living body, which is a highly light scattering medium as the depth of the object increases, the component perpendicular to the linearly polarized light increases as the amount of the component orthogonal to the depolarized linearly polarized light increases. many is transmitted, placing the polarizing plate at a predetermined polarization angle so as to reduce transmission of the object reflecting light wave components from the precursor reference light wave and the test surface of the linearly polarized light component, reducing the strong reflected light waves of the object surface An apparatus for observing light-wave reflection tomograms capable of capturing weak reflection information in the deep part of an object.

3. The light wave reflection tomogram observation apparatus according to claim 2, wherein an optical array detector is arranged as a photodetector for combined interference light, and a heterodyne beat signal is detected independently for each element. Lightwave reflection tomography observation device.

In the light wave reflected tomographic image observing apparatus according to claim 2, a light beam to form a substantially parallel light beam while converging the light to the light beam from the light source by disposing a tapered waveguide, the optical image transmitted before Symbol same optical path to further A waveguide is disposed, the precursor reference light wave is generated by a transflective mirror provided on the output end face of the optical image transmission waveguide, the other partially transmitted light is used as an object irradiation light wave, and the object reflected light wave is captured. Even if both the precursor reference light wave and the object reflected light wave propagate through the long optical path of the optical image transmission waveguide, they can be canceled in the combined interference in order to experience the same phase change, and the reflected tomographic image is constructed. Light-wave reflection tomographic image observation device.

9. The optical reflection tomography observation apparatus according to claim 8, wherein the optical image transmission waveguide includes an optical fiber bundle in which a translucent light reflection film for forming the precursor reference light wave and an irradiation light wave is applied to a light irradiation end face. A light wave tomographic image observation apparatus characterized by

9. The light wave reflection tomographic image observation apparatus according to claim 8, wherein a refractive index distribution optical fiber having a partial light reflection film for forming the precursor reference light wave and an irradiation light wave on a light irradiation end face is disposed in the optical image transmission waveguide. A light-wave reflection tomography observation apparatus characterized by

3. The light wave reflection tomographic image observation apparatus according to claim 2, wherein a semitransparent reflecting mirror is arranged in the middle of an optical path leading to the interferometer to extract a part of the object reflected light wave, and a polarizing plate is provided to reduce the precursor reference light wave. In addition, an imaging lens system is arranged to form an object reflection image on the imaging device so that it can be observed, and the cut surface position of the reflection tomogram can be observed simultaneously. Observation device.

In the light wave reflected tomographic image observing apparatus according to claim 2, the converging lens of the object illumination beam so that it can move the focal position in the subject body deep and movable in the optical axis direction, before Symbol focal position at the same time An optical reflection tomographic image observation apparatus, wherein the delay movable reflector is configured to be movable so that a combined interference signal can be detected.

3. The light wave reflection tomographic image observation apparatus according to claim 2, wherein a light beam from a light source is a diffused beam, part of which is used for the precursor reference light wave and object reflected light wave, and another part is an object made of a cone-shaped hollow transparent body. A light wave reflection tomographic image observation apparatus, wherein an illumination head is arranged and guided to form the reflected light observation illumination light according to claim 11.

3. The light wave reflection tomographic image observation apparatus according to claim 2, wherein the optical image waveguide is arranged with respect to a light beam from a light source and introduced into a translucent reflecting mirror for splitting the light beam, and transmitted light is the precursor reference light wave and object reflected light wave. 12. The object illumination head according to claim 11, wherein the reflected light wave is guided through an optical fiber bundle having a circumferentially arranged exit end through a lens, and an object illumination head made of a cone-shaped hollow transparent body in close contact with the exit end. A light-wave reflection tomographic image observation apparatus characterized by forming illumination light for reflection image observation.

15. The light wave reflection tomographic image observation apparatus according to claim 14, wherein a component ahead of the optical image waveguide and an imaging device unit are made into a single-portable portable type, and a refractive index distribution optical fiber for the precursor reference light wave and object reflected light wave is provided. A light wave reflection tomographic image observation apparatus characterized in that it is arranged and guided to a multiplexing interferometer.

In the light wave reflected tomographic image observing apparatus according to claim 14, wherein disposed separately daylight color light source of the light source of the reflected image observation illumination light, the optical fiber bundle waveguide to form an illumination light, for observation reflected tomographic image Is a light wave reflection tomographic image observing apparatus characterized in that the light source is arranged and an independent light source is provided .

In the light wave reflected tomographic image observing apparatus according to claim 2, wherein, when generating the object reflection light wave test body is the Doppler shift frequency include dynamic scattering potential portion, the light of the combined interference light having the vertical sectional distribution by combining a plurality of the space dividing component signal by detecting the Doppler shift beat component output from the detector means for detecting amplitude information of the scattered light waves from the dynamic scattering potential, the Doppler shift beat Means for calculating and displaying the moving speed and direction of the dynamic scattering potential for each three-dimensional pixel of the vertical cross-sectional image and the depth reflection image based on the component frequency so that the dynamic structure of the deep part of the living body can be visualized; A light reflection tomography observation device.