JP4126792B2 - Radiation thermometer - Google Patents

Description

【００４３】
で与えられるＬ３だけ前記集光素子の焦点よりも集光素子から遠くに設置したものである。
【００４４】
そして、筐体には集光素子で集光された赤外線が入射し、また筐体の開口部は集光素子の焦点距離ｆと、筐体の開口部の半径ｒＳと、仮想先端点と光軸との距離ｒαと、仮想先端点と集光素子との距離Ｌαと、集光素子の半径ｒ３を用いて、前記の式で与えられるＬ３だけ集光素子の焦点よりも集光素子から遠くに設置することで、プローブ内壁から集光素子に入射する赤外線を筐体の開口部以外の位置へ進行させることができ、受光領域を制限することができる。そして筐体の開口部に入射した赤外線が赤外受光素子に入射するので、鼓膜および／またはその近傍から放射されプローブを通過した放射光のみをスポット的に検出することが可能となる。
【００４５】
本発明の請求項１４にかかる放射体温計は、筐体の開口部を、集光素子の縁から光軸に対して前記集光素子の縁と同じ側のプローブの内壁に接するように引いた直線が前記プローブの先端の面と交叉する仮想先端点の集光素子による像点よりも前記集光素子から遠い領域に設置するものである。
【００４６】
そして、筐体には集光素子で集光された赤外線が入射し、また筐体の開口部を、集光素子の縁から光軸に対して前記集光素子の縁と同じ側のプローブの内壁に接するように引いた直線が前記プローブの先端の面と交叉する仮想先端点の集光素子による像点よりも前記集光素子から遠い領域に設置することで、プローブ内壁から集光素子に入射する赤外線を筐体の開口部以外の位置へ進行させることができ、受光領域を制限することができる。そして筐体の開口部に入射した赤外線が赤外受光素子に入射するので、鼓膜および／またはその近傍から放射されプローブを通過した放射光のみをスポット的に検出することが可能となる。
【００４７】
本発明の請求項１５にかかる放射体温計は、筐体の開口部を、集光素子の縁から光軸に対して前記集光素子の縁と同じ側のプローブの内壁に接するように引いた直線が前記プローブの先端の面と交叉する仮想先端点から光軸を挟んで前記仮想先端点と反対側の前記集光素子の縁を通過して前記集光素子による前記仮想先端点の像点へ到達する前記集光素子の子午面内の２つの光路で挟まれた領域に設置するものである。
【００４８】
そして、筐体には集光素子で集光された赤外線が入射し、また筐体の開口部を、集光素子の縁から光軸に対して前記集光素子の縁と同じ側のプローブの内壁に接するように引いた直線が前記プローブの先端の面と交叉する仮想先端点から光軸を挟んで前記仮想先端点と反対側の前記集光素子の縁を通過して前記集光素子による前記仮想先端点の像点へ到達する前記集光素子の子午面内の２つの光路で挟まれた領域に設置することで、プローブ内壁から集光素子に入射する赤外線を筐体の開口部以外の位置へ進行させることができ、受光領域を制限することができる。そして筐体の開口部に入射した赤外線が赤外受光素子に入射するので、鼓膜および／またはその近傍から放射されプローブを通過した放射光のみをスポット的に検出することが可能となる。
【００４９】
本発明の請求項１６にかかる放射体温計は、筐体の開口部を、集光素子の焦点距離ｆと、前記筐体の開口部の半径ｒＳと、前記集光素子の縁から光軸に対して前記集光素子の縁と同じ側の前記プローブの内壁に接するように引いた直線が前記プローブの先端の面と交叉する仮想先端点と光軸との距離ｒαと、前記仮想先端点と前記集光素子との距離Ｌαと、前記集光素子の半径ｒ３を用いて、
【００５０】
【数４】

【００５１】
で表されるＬ３だけ前記集光素子の焦点よりも集光素子から遠くに設置したものである。
【００５２】
そして、筐体には集光素子で集光された赤外線が入射し、また筐体の開口部は集光素子の焦点距離ｆと、筐体の開口部の半径ｒＳと、仮想先端点と光軸との距離ｒαと、仮想先端点と前記集光素子との距離Ｌαと、集光素子の半径ｒ３を用いて、前記の式で表されるＬ３だけ前記集光素子の焦点よりも集光素子から遠くに設置することで、プローブ内壁から集光素子に入射する赤外線を筐体の開口部以外の位置へ進行させることができ、受光領域を制限することができる。そして筐体の開口部に入射した赤外線が赤外受光素子に入射するので、鼓膜および／またはその近傍から放射されプローブを通過した放射光のみをスポット的に検出することが可能となる。
【００５３】
本発明の請求項１７にかかる放射体温計は、集光素子は屈折レンズで構成している。
【００５４】
そして屈折レンズにより、筐体の開口部には集光された赤外線が入射する。
【００５５】
本発明の請求項１８にかかる放射体温計は、集光素子は集光ミラーで構成している。
【００５６】
そして集光ミラーにより、筐体の開口部には集光された赤外線が入射する。
【００５７】
本発明の請求項１９にかかる放射体温計は、集光ミラーは、前記集光ミラーに入射する第１の光軸と、前記集光ミラーから射出し筐体の開口部に入射する第２の光軸とを屈曲させるものである。
【００５８】
そして、外耳道に挿入して測定する放射体温計としての使い勝手を考慮しプローブと本体を屈曲させたとき、この角度に併せて光学系も屈曲させることができる。従って、使い勝手がよく、耳孔に挿入しやすくなることで挿入方向が安定しやすく精度よく体温測定ができる。
【００５９】
本発明の請求項２０にかかる放射体温計は、筐体は少なくとも内面を反射率の高い材料で構成したものである。
【００６０】
そして、筐体の内面を反射率の高い材料とすることで、赤外受光素子には筐体の開口部から入射する赤外線を反射させながら有効に入射させることができる。
【００６１】
本発明の請求項２１にかかる放射体温計は、筐体は金属で構成したものである。
【００６２】
そして、金属は一般に反射率が高いので、筐体を簡易に構成できる。
【００６３】
【実施例】
（実施例１）
以下、本発明の実施例１を図１〜図４を参照しながら説明する。図１は本発明の放射体温計の構成図である。図２〜図３は複数のプローブの側面図、図４は受光部およびプローブの構成図である。
【００６４】
図１において１はプローブで体温測定に際して外耳道に挿入する部分であり、鼓膜に向かう側の先端方向に細くした形状で、先端は開口していて、反対側の端部には本体５と着脱可能なように突起部６を備えている。そしてプローブ１を本体５に取り付ける時は、押し圧により突起部６が内側に歪んで本体５に取り付けられる。はずすときはプローブ１を指で押さえることで、同様に突起部６を内側に歪ませてはずす。本体５には収納部７があり、体温測定をしないときはプローブ１をはずして収納部７に収納する。収納部７は蓋８を備え、収納時に開閉する。非測定時にプローブ１をはずすことで本体そのものの形状となり、収納しやすい形状となる。またはずしたプローブ１は収納部７で保管するので紛失する可能性は少ない。
【００６５】
９は受光部でプローブ１の開口を通過した赤外線のみを受光し、その赤外線量に応じた電気信号を出力する。４は信号処理手段で受光部９から入力する信号に基づいて温度換算する。ここで換算される温度は赤外線の照射源温度であり、鼓膜および／またはその近傍の温度に相当する。
【００６６】
信号処理手段４で換算された温度を体温として報知手段１０で使用者に報知する。報知手段１０は信号処理手段４で換算した体温を数字で表示する数字表示手段１１と音声報知手段１２から成る。数字表示手段１１は例えば液晶表示器であり、音声報知手段１２は例えばスピーカである。
【００６７】
ここで、受光部９は後に詳述するようにプローブ１の開口を通過した赤外線のみを受光するのでプローブ１の温度変動の影響を受けることはなく、また導波管も必要ない。プローブ１は着脱自在であり、複数個具備していて、例えば図２に示すようにそれぞれ、異なる記号を印刷している。図２では（ａ）には「Ａ」、（ｂ）には「Ｂ」、（ｃ）には「Ｃ」、（ｄ）には「Ｄ」の記号を印刷している。例えば家庭で使う場合、４人家族であれば個人ごとに使うプローブを決めておけば、記号が目印になって間違うことはなく耳からの感染は避けることができる。また導波管を持たないのでプローブ１の先端部分は開口していてもよく、膜で覆うようなことはないので、膜の赤外線透過率のばらつきによる温度誤差はない。
【００６８】
個人ごとに使うプローブを間違えないように目視で判断可能な差異を設ける方法として前記した記号の違いの他に、色を変えたり異なる図柄を印刷してもよい。また図３に示すように寸法を変えてもよい。図３では（ａ）を最も短く、（ｂ）、（ｃ）、（ｄ）の順に長くしている。この場合には目視で判断可能な差異により使うプローブを間違えない他に、耳の小さい幼児ならば（ａ）、耳の大きい大人は（ｄ）を使うなどすれば最も耳に挿入しやすい寸法を選択できるという効果もある。
【００６９】
また音声報知手段１２で音声報知するので、暗闇で測定する場合や目の不自由な人が測定する場合でも検温結果を知ることができる。また数字表示手段１１でも報知しているので、騒音の大きい環境で測定する場合や耳の不自由な人が測定する場合でも検温結果を知ることができる。耳で温度を測定するので音声報知手段１２は十分小さな音量で被験者に報知することができ、被験者にのみ検温結果が聞こえ、被験者以外には検温結果が聞こえないようにできて、被験者の周囲に不要な雑音で迷惑をかけることはない。また被験者のプライバシーも守ることができる。
【００７０】
受光部９の構成を図４により説明する。図４において、１３は集光素子である屈折レンズ、３は赤外受光素子で、反射率の高い金属により構成された筐体１４に内蔵され、筐体１４には赤外線が入射する開口部１５が設けられている。１６は遮光体である。遮光体１６は少なくともその内面は後に詳述する合成樹脂等の反射率の低い反射抑制手段で構成している。Ａ、Ａ’は屈折レンズ１３の縁からこの縁と同じ側のプローブ１の内壁に接するように引いた直線とプローブ１の先端の面との交点で、図４のように開口から本体装着部分までの間が直線的なプローブであればプローブ１の先端内壁に位置する点である。Ｂはプローブ１の内壁における点、即ち受光したくない領域の点、Ｆは屈折レンズ１３の焦点、ＦＡは屈折レンズ１３によるＡの像点、ＦＡ’は屈折レンズ１３によるＡ’の像点、ＦＢは屈折レンズ１３によるＢの像点、Ｋ１ＡはＡから光軸に対して同じ側の屈折レンズ１３の縁を通過してＦＡへ進行する光（マージナル光線）の光路、Ｋ２ＡはＡから光軸と平行に進んで焦点Ｆを通過してＦＡに到達する光の光路、Ｋ３ＡはＡから屈折レンズ１３の中心を通過してＦＡに到達する光の光路、Ｋ４ＡはＡから光軸を挟んで反対側の屈折レンズ１３の縁を通過してＦＡに到達する光（マージナル光線）の光路である。また同様にＫ１Ａ’はＡ’から光軸に対して同じ側の屈折レンズ１３の縁を通過してＦＡ’へ進行する光（マージナル光線）の光路、Ｋ２Ａ’はＡ’から光軸と平行に進んで焦点Ｆを通過してＦＡ’に到達する光の光路、Ｋ３Ａ’はＡ’から屈折レンズ１３の中心を通過してＦＡ’に到達する光の光路、Ｋ４Ａ’はＡ’から光軸を挟んで反対側の屈折レンズ１３の縁を通過してＦＡ’に到達する光（マージナル光線）の光路、Ｋ３ＢはＢから屈折レンズ１３の中心を通過してＦＢに到達する光の光路、ＦＸは光路Ｋ１Ａと光路Ｋ１Ａ’の交点である。
【００７１】
プローブ１の開口を通過する赤外線のみが筐体１４の開口部１５に入射するような光学系を設計する。
【００７２】
筐体１４を遮光体１６に取り付け、屈折レンズ１３を通過しない赤外線は筐体１４が受光しないようにする。屈折レンズ１３を通った赤外線のみ受光する構成にした上で以下の設計を行う。
【００７３】
Ａから放射される光は光路Ｋ１Ａ、Ｋ２Ａ、Ｋ３Ａ、Ｋ４Ａなどを通ってＡの像点ＦＡに到達する。幾何光学で周知の通り、Ａの像点ＦＡは光軸を挟んでＡと反対側に形成される。図４中に示すように、光路Ｋ２Ａを通る光は、屈折レンズ１３を通過してＦで光軸と交叉したのち光軸から離れながらＦＡに到達する。同じように、光路Ｋ１Ａを通る光は、屈折レンズ１３を通過して光軸と交叉したのち光軸から離れながらＦＡに到達する。光路Ｋ３Ａを通る光は、屈折レンズ１３で光軸と交叉したのち光軸から離れながらＦＡに到達する。光路Ｋ４Ａを通る光は、光軸と交叉して屈折レンズ１３を通過し、屈折レンズ１３を通過してからは光軸と交叉せずにＦＡに到達する。このように、光路Ｋ１Ａと光軸が交叉する点ＦＸよりも屈折レンズ１３から離れた位置かつＦＡよりも屈折レンズ１３に近い位置で、Ａから放射される光が通過しない領域が存在する。この領域は、ＦＸとＦＡとＦＡ’が形成する三角形の内側となる。この三角形の内側に筐体１４の開口部１５を設置することで、Ａ、Ａ’から放射される光は、筐体１４の内部には入射せず赤外受光素子３では受光しない受光部が得られる。
【００７４】
受光したくないプローブ１内壁の領域中のＢ点は、Ａよりも光軸から遠いため、屈折レンズ１３によるＢの像点ＦＢがＦＡより光軸から遠くなることは周知の通りである。従って、ＦＸとＦＡとＦＡ’が形成する三角形の内側に筐体１４の開口部１５を設置することによってＡ、Ａ’から放射される赤外線が筐体１４の内部に入射しないようにすれば、自動的にＢからの赤外線も入射せず、赤外受光素子３では受光しない構成となる。
【００７５】
以上のように、ＦＸとＦＡとＦＡ’が形成する三角形の内側に筐体１４の開口部１５を設置することによって、光軸付近の受光したい領域、即ちプローブ１の開口を通過した鼓膜および／またはその近傍から放射される赤外線のみを赤外受光素子３が受光するような受光部が得られる。
【００７６】
（実施例２）
次に本発明の実施例２を図５を用いて説明する。図５は本発明の実施例２における放射体温計の受光部およびプローブを示す構成図である。図５において、１３は屈折レンズ、３は赤外受光素子で、反射率の高い金属により構成された筐体１４に内蔵され、筐体１４には赤外線が入射する開口部１５が設けられている。１６は遮光体である。Ａ、Ａ’は屈折レンズ１３の縁からプローブ１の内壁に接するように引いた直線とプローブ１の先端の面との交点で、図５のように開口から本体装着部までの間が直線的なプローブであればプローブ１の先端内壁に位置する点である。Ｂはプローブ１の内壁における点、即ち受光したくない領域の点、Ｆは屈折レンズ１３の焦点、ＦＡは屈折レンズ１３によるＡの像点、ＦＡ’は屈折レンズ１３によるＡ’の像点、ＦＢは屈折レンズ１３によるＢの像点、Ｋ１ＡはＡから光軸に対して同じ側の屈折レンズ１３の縁を通過してＦＡへ進行する光（マージナル光線）の光路、Ｋ２ＡはＡから光軸と平行に進んで焦点Ｆを通過してＦＡに到達する光の光路、Ｋ３ＡはＡから屈折レンズ１３の中心を通過してＦＡに到達する光の光路、Ｋ４ＡはＡから光軸を挟んで反対側の屈折レンズ１３の縁を通過してＦＡに到達する光（マージナル光線）の光路、Ｋ１Ａ’はＡ’から光軸に対して同じ側の屈折レンズ１３の縁を通過してＦＡ’へ進行する光（マージナル光線）の光路、Ｋ２Ａ’はＡ’から光軸と平行に進んで焦点Ｆを通過してＦＡ’に到達する光の光路、Ｋ３Ａ’はＡ’から屈折レンズ１３の中心を通過してＦＡ’に到達する光の光路、Ｋ４Ａ’はＡ’から光軸を挟んで反対側の屈折レンズ１３の縁を通過してＦＡ’に到達する光（マージナル光線）の光路、Ｋ３ＢはＢから屈折レンズ１３の中心を通過してＦＢに到達する光の光路、Ｋ４ＢはＢから光軸を挟んで反対側の屈折レンズ１３の縁を通過してＦＢに到達する光（マージナル光線）の光路、ＦＸは光路Ｋ１Ａと光路Ｋ１Ａ’の交点、ＦＹは光路Ｋ４Ａと光路Ｋ４Ａ’の交点である。
【００７７】
プローブ１の開口を通過する赤外線のみが筐体１４の開口部１５に入射するような光学系を設計する。
筐体１４を遮光体１６に取り付け、屈折レンズ１３を通過しない赤外線は筐体１４が受光しないようにする。屈折レンズ１３を通った赤外線のみ受光する構成にした上で以下の設計を行う。
【００７８】
Ａから放射される光は光路Ｋ１Ａ、Ｋ２Ａ、Ｋ３Ａ、Ｋ４Ａなどを通ってＡの像点ＦＡに到達する。幾何光学で周知の通り、Ａの像点ＦＡは光軸を挟んでＡと反対側に形成される。図５中に示すように、光路Ｋ２Ａを通る光は、屈折レンズ１３を通過してＦで光軸と交叉してＦＡに到達し光軸から離れていく。同じように、光路Ｋ１Ａを通る光は、屈折レンズ１３を通過して光軸と交叉してＦＡに到達し光軸から離れていく。光路Ｋ３Ａを通る光は、屈折レンズ１３で光軸と交叉してＦＡに到達し光軸から離れていく。光路Ｋ４Ａを通る光は、光軸と交叉して屈折レンズ１３を通過し、屈折レンズ１３を通過してからは光軸と交叉せずにＦＡに到達し、その後光軸に近づくかあるいは遠ざかっていく。
【００７９】
このように、Ａの像点ＦＡよりも屈折レンズから離れた位置でＡから放射される光が通過しない領域が存在する。この領域は、ＦＡよりも屈折レンズ１３から遠い部分の光路Ｋ４Ａと、ＦＡ’よりも屈折レンズ１３から遠い部分の光路Ｋ４Ａ’で挟まれた領域である。この領域に筐体１４の開口部１５を設置することで、Ａ、Ａ’から放射される光は、筐体１４の内部には入射せず赤外受光素子３では受光しない受光部が得られる。
【００８０】
受光したくないプローブ１内壁の領域中のＢ点は、Ａよりも光軸から遠いため、屈折レンズ１３によるＢの像点ＦＢがＦＡより光軸から遠くなることは周知の通りである。従って、ＦＡよりも屈折レンズ１３から遠い部分の光路Ｋ４Ａと、ＦＡ’よりも屈折レンズ１３から遠い部分の光路Ｋ４Ａ’で挟まれた領域内に筐体１４の開口部１５を設置することによってＡ、Ａ’から放射される赤外線が筐体１４の内部に入射しないようにすれば、自動的にＢからの赤外線も入射せず、赤外受光素子３では受光しない構成となる。
【００８１】
以上のように、ＦＡよりも屈折レンズ１３から遠い部分の光路Ｋ４Ａと、ＦＡ’よりも屈折レンズ１３から遠い部分の光路Ｋ４Ａ’で挟まれた領域内に筐体１４の開口部１５を設置することによって、光軸付近の受光したい領域、即ちプローブ１の開口を通過した鼓膜および／またはその近傍から放射される赤外線のみを赤外受光素子３が受光するような受光部が得られる。
【００８２】
（実施例３）
次に本発明の実施例３を図６を用いて説明する。図６は本発明の実施例３における放射体温計の受光部およびプローブを示す構成図である。ここでプローブ１は前記実施例と異なり、より外耳道に挿入し易いようＲ付けの部分を持たせている。図６において、１３は屈折レンズ、３は赤外受光素子で、反射率の高い金属により構成された筐体１４に内蔵され、筐体１４には赤外線が入射する開口部１５が設けられている。１６は遮光体である。α、α’は屈折レンズ１３の縁からこの縁と光軸に対して同じ側のプローブ１内壁へ接する直線がプローブ１の先端面と交わる仮想先端点、Ｆは屈折レンズ１３の焦点、Ｆα、Ｆα’はそれぞれ屈折レンズ１３によるα、α’の像点、Ｋ１αはαから光軸に対して同じ側の屈折レンズ１３の縁を通過してＦαへ進行する光（マージナル光線）の光路、Ｋ２αはαから光軸と平行に進んで焦点Ｆを通過してＦαに到達する光の光路、Ｋ３αはαから屈折レンズ１３の中心を通過してＦαに到達する光の光路、Ｋ４αはαから光軸を挟んで反対側の屈折レンズ１３の縁を通過してＦαに到達する光（マージナル光線）の光路、Ｋ１α’はα’から光軸に対して同じ側の屈折レンズ１３の縁を通過してＦα’へ進行する光（マージナル光線）の光路、Ｋ２α’はα’から光軸と平行に進んで焦点Ｆを通過してＦα’に到達する光の光路、Ｋ３α’はα’から屈折レンズ１３の中心を通過してＦα’に到達する光の光路、Ｋ４α’はα’から光軸を挟んで反対側の屈折レンズ１３の縁を通過してＦα’に到達する光（マージナル光線）の光路、ＦＸは光路Ｋ１αと光軸との交点である。
【００８３】
プローブ１の開口を通過する赤外線のみが筐体１４の開口部１５に入射するような光学系を設計する。
【００８４】
筐体１４を遮光体１６に取り付け、屈折レンズ１３を通過しない赤外線は筐体１４が受光しないようにする。屈折レンズ１３を通った赤外線のみ受光する構成にした上で以下の設計を行う。
【００８５】
鼓膜および／またはその近傍から発せられプローブ１の開口を通過した赤外光のみ筐体１４の開口部１５に入射するようにするためには、プローブ１から放射される赤外光を受光しないようにすればよい。そのため、受光したい領域と受光したくない領域の境界に位置する点を仮想し、この点から、光軸に対してこの仮想した境界に位置する点と同じ側の屈折レンズ１３の縁を通過する光（マージナル光線）の光路よりも、光軸から遠くに位置するようにプローブ１を設置すればよい。そこで、上記仮想の境界に位置する点を、屈折レンズ１３の縁からこの縁と光軸に対して同じ側のプローブ１内壁へ接する直線がプローブ１の先端面と交わる点α、α’として、ＦαとＦα’とＦＸで形成される三角形の内側に筐体１４の開口部１５を設置する。これにより、プローブ１をαと屈折レンズ１３の間で光路Ｋ１α、Ｋ１α’よりも光軸から遠くに位置させることになるため、プローブ１からの光を受光しない光学系が得られる。
【００８６】
上記について詳細を以下に述べる。αから放射される光は光路Ｋ１α、Ｋ２α、Ｋ３α、Ｋ４αなどを通ってαの像点Ｆαに到達する。幾何光学で周知の通り、αの像点Ｆαは光軸を挟んでαと反対側に形成される。図６中に示すように、光路Ｋ２αを通る光は、屈折レンズ１３を通過してＦで光軸と交叉したのち光軸から離れながらＦαに到達する。同じように、光路Ｋ１αを通る光は、屈折レンズ１３を通過して光軸と交叉したのち光軸から離れながらＦαに到達する。光路Ｋ３αを通る光は、屈折レンズ１３で光軸と交叉したのち光軸から離れながらＦαに到達する。光路Ｋ４αを通る光は、光軸と交叉して屈折レンズ１３を通過し、屈折レンズ１３を通過してからは光軸と交叉せずにＦαに到達する。このように、光路Ｋ１αと光軸が交叉する点ＦＸよりも屈折レンズ１３から離れた位置かつＦαよりも屈折レンズ１３に近い位置で、αから放射される光が通過しない領域が存在する。同じように、α’についても、光路Ｋ１α’と光軸が交叉する点よりも屈折レンズ１３から離れた位置かつＦα’よりも屈折レンズ１３に近い位置で、α’から放射される光が通過しない領域が存在する。この、Ｆα、Ｆα’、ＦＸで形成される三角形の内側よりに筐体１４の開口部１５を設置することで、α、α’から放射される光を赤外受光素子３が受光しない受光部が得られる。αと屈折レンズ１３の間の光路Ｋ１αより光軸から遠い部分からの光は、αと同じ面内で光軸からの距離がαより大きい点からの光と置き換えられる。この点の屈折レンズ１３による像点はＦαよりも光軸から遠くなることは幾何光学で周知の通りである。そのため、αからの光を受光しないようにすれば、αよりも光軸から遠い点からの光を受光せず、従ってプローブ１からの光を受光しない。同様に、α’と屈折レンズ１３の間の光路Ｋ１α’より光軸から遠い部分からの光は、α’と同じ面内で光軸からの距離がα’より大きい点からの光と置き換えられる。この点の屈折レンズ１３による像点はＦα’よりも光軸から遠くなることは幾何光学で周知の通りである。そのため、α’からの光を受光しないようにすれば、α’よりも光軸から遠い点からの光を受光せず、従ってプローブ１からの光を受光しない。
【００８７】
このように、ＦαとＦα’とＦＸで形成される三角形の内側に筐体１４の開口部１５を設置することでα、α’から放射される赤外線が入射しないようにすれば、自動的にプローブ１から放射される赤外線も筐体１４の内部には入射せず赤外受光素子３が受光しない構成となる。
【００８８】
以下、αからの光を受光しないような筐体１４の開口部１５の位置を求める。
【００８９】
開口部１５はＦαよりも屈折レンズ１３に近い。この時、次式が成り立つ。
【００９０】
ＬαＦ≧ｆ＋Ｌ３ （１）
したがって
Ｌ３≦ＬαＦ−ｆ （２）
ここでＬαＦは屈折レンズ１３の中心からαの像点Ｆαまでの距離、ｆは屈折レンズ１３の中心から焦点Ｆまでの距離、Ｌ３は焦点Ｆから開口部１５までの距離である。
【００９１】
図６に示すように、受光面は光路Ｋ１αと光軸が交わる点ＦＸとＦαとの間であるので、αからＦαまでの各光路のうち受光面で開口部１５に最も近づくものはＫ１αである。したがって、αからの光が開口部１５に入射しないためには、次式を満たす必要がある。
【００９２】
ｒαＳ１＞ｒＳ （３）
ここで、ｒαＳ１は光路Ｋ１αと開口部１５の受光面との交点ＦαＳ１から光軸までの距離、ｒＳは開口部１５の半径である。また屈折レンズ１３の半径をｒ３、光軸から像点Ｆαまでの距離をｒαＦとしたとき、幾何光学で周知の通りｒ３、ｒαＦ、ｒαＳ１、Ｌ３、ｆは幾何関係として（式４）を満たす。
【００９３】
【数５】

【００９４】
したがって、（式５）を満たす。
【００９５】
【数６】

【００９６】
（式５）を（式３）へ代入することで（式６）が得られる。
【００９７】
【数７】

【００９８】
（式２）、（式６）から、αから放射される光が開口部１５から入射しないための条件は（式７）となる。
【００９９】
【数８】

【０１００】
さらにαから光軸までの距離をｒα、プローブ１の先端から屈折レンズ１３の中心までの距離をＬαとしたときに、幾何光学で周知の通り、ｒα、Ｌα、ｒαＦ、ＬαＦは幾何関係として（式８）を満たす。
【０１０１】
【数９】

【０１０２】
したがって、（式９）を満たす。
【０１０３】
【数１０】

【０１０４】
（式９）を（式７）へ代入することにより、αから放射される光が開口部１５から入射しないための条件は（式１０）となる。
【０１０５】
【数１１】

【０１０６】
また、ガウスの公式から（式１１）が成り立つ。
【０１０７】
【数１２】

【０１０８】
したがって、（式１２）が成り立つ。
【０１０９】
【数１３】

【０１１０】
（式１２）を（式１０）に代入することにより、αから放射される光が開口部１５から入射しないための条件は（式１３）となる。
【０１１１】
【数１４】

【０１１２】
以上のように、プローブ１先端のαから放射される光が開口部１５から筐体１４の内部に入射せず赤外受光素子３で受光しないためには、（式７）、或いは（式１０）、或いは（式１３）を満たすよう光学系を設計する必要がある。（式７）、（式１０）、（式１３）で与えられるＬ３だけ、開口部１５を屈折レンズ１３の焦点からずらして設置することで、プローブ１から放射される赤外線が開口部１５から入射せず、鼓膜および／またはその近傍から発せられプローブ１の開口を通過した赤外線のみが開口部１５から入射して赤外受光素子３で受光させることができる。
【０１１３】
（実施例４）
次に本発明の実施例４を図７に基づいて説明する。図７は本発明の実施例４における放射体温計の受光部およびプローブを示す構成図である。図７において、１はプローブで実施例３と同様にＲ付けの部分を持たせている。また１３は屈折レンズ、３は赤外受光素子で、反射率の高い金属により構成された筐体１４に内蔵され、筐体１４には赤外線が入射する開口部１５が設けられている。１６は遮光体である。α、α’は屈折レンズ１３の縁からこの縁と光軸に対して同じ側のプローブ１内壁へ接する直線がプローブ１の先端面と交わる仮想先端点、Ｆは屈折レンズ１３の焦点、Ｆα、Ｆα’はそれぞれ屈折レンズ１３によるα、α’の像点、Ｋ１αはαから光軸に対して同じ側の屈折レンズ１３の縁を通過してＦαへ進行する光（マージナル光線）の光路、Ｋ２αはαから光軸と平行に進んで焦点Ｆを通過してＦαに到達する光の光路、Ｋ３αはαから屈折レンズ１３の中心を通過してＦαに到達する光の光路、Ｋ４αはαから光軸を挟んで反対側の屈折レンズ１３の縁を通過してＦαに到達する光（マージナル光線）の光路、Ｋ１α’はα’から光軸に対して同じ側の屈折レンズ１３の縁を通過してＦα’へ進行する光（マージナル光線）の光路、Ｋ２α’はα’から光軸と平行に進んで焦点Ｆを通過してＦα’に到達する光の光路、Ｋ３α’はα’から屈折レンズ１３の中心を通過してＦα’に到達する光の光路、Ｋ４α’はα’から光軸を挟んで反対側の屈折レンズ１３の縁を通過してＦα’に到達する光（マージナル光線）の光路、ＦＸは光路Ｋ１αと光軸との交点である。
【０１１４】
プローブ１の開口を通過する赤外線のみが筐体１４の開口部１５に入射するような光学系を設計する。
【０１１５】
筐体１４を遮光体１６に取り付け、屈折レンズ１３を通過しない赤外線は筐体１４が受光しないようにする。屈折レンズ１３を通った赤外線のみ受光する構成にした上で以下の設計を行う。
【０１１６】
鼓膜および／またはその近傍から発せられプローブ１の開口を通過した赤外光のみを受光するためには、プローブ１から放射される赤外光を受光しないようにすればよい。そのため、受光したい領域と受光したくない領域の境界に位置する点を仮想し、この点から、光軸に対してこの仮想した境界に位置する点と同じ側の屈折レンズ１３の縁を通過する光（マージナル光線）の光路よりも、光軸から遠くに位置するようにプローブ１を設置すればよい。そこで、上記仮想の境界に位置する点を、屈折レンズ１３の縁からこの縁と光軸に対して同じ側のプローブ１内壁へ接する直線がプローブ１の先端面と交わる点α、α’として、Ｆαよりも屈折レンズ１３から遠い部分の光路Ｋ４αと、Ｆα’よりも屈折レンズ１３から遠い部分の光路Ｋ４α’で挟まれた領域に赤外受光素子３を設置する。これにより、プローブ１をαと屈折レンズ１３の間で光路Ｋ１α、Ｋ１α’よりも光軸から遠くに位置させることになるため、プローブ１からの光を受光しない光学系が得られる。
【０１１７】
上記について詳細を以下に述べる。
【０１１８】
αから放射される光は光路Ｋ１α、Ｋ２α、Ｋ３α、Ｋ４αなどを通ってαの像点Ｆαに到達する。幾何光学で周知の通り、αの像点Ｆαは光軸を挟んでαと反対側に形成される。図７中に示すように、光路Ｋ２αを通る光は、屈折レンズ１３を通過してＦで光軸と交叉してＦαに到達し光軸から離れていく。同じように、光路Ｋ１αを通る光は、屈折レンズ１３を通過して光軸と交叉してＦαに到達し光軸から離れていく。光路Ｋ３αを通る光は、屈折レンズ１３で光軸と交叉してＦαに到達し光軸から離れていく。光路Ｋ４αを通る光は、光軸と交叉して屈折レンズ１３を通過し、屈折レンズ１３を通過してからは光軸と交叉せずにＦαに到達し、その後光軸に近づくかあるいは遠ざかっていく。このように、αの像点Ｆαよりも屈折レンズ１３から離れた位置でαから放射される光が通過しない領域が存在する。同じようにα’についても、α’の像点Ｆα’よりも屈折レンズ１３から離れた位置でα’から放射される光が通過しない領域が存在する。この、Ｆαよりも屈折レンズ１３から遠い部分の光路Ｋ４αと、Ｆα’よりも屈折レンズ１３から遠い部分の光路Ｋ４α’で挟まれた領域内に開口部１５を設置することによってα、α’から放射される赤外線を受光しない受光部が得られる。αと屈折レンズ１３の間の光路Ｋ１αより光軸から遠い部分からの光は、αと同じ面内で光軸からの距離がαより大きい点からの光と置き換えられる。この点の屈折レンズ１３による像点はＦαよりも光軸から遠くなることは幾何光学で周知の通りである。そのため、αからの光が開口部１５に入射しないようにすれば、αよりも光軸から遠い点からの光は入射せず、従ってプローブ１からの光は開口部１５からは入射しない。同様に、α’と屈折レンズ１３の間の光路Ｋ１α’より光軸から遠い部分からの光は、α’と同じ面内で光軸からの距離がα’より大きい点からの光と置き換えられる。この点の屈折レンズ１３による像点はＦα’よりも光軸から遠くなることは幾何光学で周知の通りである。そのため、α’からの光が開口部１５に入射しないようにすれば、α’よりも光軸から遠い点からの光は入射せず、従ってプローブ１からの光は開口部１５から入射しない。
【０１１９】
このように、Ｆαよりも屈折レンズ１３から遠い部分の光路Ｋ４αと、Ｆα’よりも屈折レンズ１３から遠い部分の光路Ｋ４α’で挟まれた領域に開口部１５を設置することでα、α’から放射される赤外線が入射しないようにすれば、自動的にプローブ１から放射される赤外線も入射せず赤外受光素子３では受光しない構成となる。
【０１２０】
以下、αからの光を受光しないような開口部１５の位置を求める。
【０１２１】
開口部１５はＦαよりも屈折レンズ１３から遠い。この時、次式が成り立つ。
【０１２２】
ＬαＦ≦ｆ＋Ｌ３ （１４）
したがって
Ｌ３≧ＬαＦ−ｆ （１５）
ここでＬαＦは屈折レンズ１３の中心からαの像点Ｆαまでの距離、ｆは屈折レンズ１３の中心から焦点Ｆまでの距離、Ｌ３は焦点Ｆから開口部１５までの距離である。
【０１２３】
図７に示すように、受光面はＦαよりも屈折レンズ１３から遠いので、αからＦαまでの各光路のうち受光面で開口部１５に最も近づくものはＫ４αである。したがって、αからの光が開口部１５に入射しないためには、次式を満たす必要がある。
【０１２４】
ｒαＳ４＞ｒＳ （１６）
ここで、ｒαＳ４は光路Ｋ４αと開口部１５の受光面との交点ＦαＳ４から光軸までの距離、ｒＳは開口部１５の半径である。また屈折レンズ１３の半径をｒ３、光軸から像点Ｆαまでの距離をｒαＦとしたとき、幾何光学で周知の通りｒ３、ｒαＦ、ＬαＦ、ｒαＳ４、Ｌ３、ｆは幾何関係として（式１７）を満たす。
【０１２５】
【数１５】

【０１２６】
したがって（式１８）を満たす。
【０１２７】
【数１６】

【０１２８】
（式１８）を（式１６）へ代入することで（式１９）が得られる。
【０１２９】
【数１７】

【０１３０】
（式１５）、（式１９）から、αから放射される光が開口部１５に入射しないための条件は（式２０）となる。
【０１３１】
【数１８】

【０１３２】
さらにαから光軸までの距離をｒα、プローブ１の先端から屈折レンズ１３の中心までの距離をＬαとしたときに、幾何光学で周知の通り、ｒα、Ｌα、ｒαＦ、ＬαＦは幾何関係として前記した（式８）を満たす。したがって前記した（式９）を満たす。
【０１３３】
（式９）を（式２０）へ代入することにより、αから放射される光が開口部１５に入射しないための条件は（式２１）となる。
【０１３４】
【数１９】

【０１３５】
また、ガウスの公式から前記した（式１１）が成り立つ。したがって前記した（式１２）が成り立つ。
【０１３６】
（式１２）を（式２１）に代入することにより、αから放射される光を赤外受光素子３で受光しないための条件は（式２２）となる。
【０１３７】
【数２０】

【０１３８】
以上のように、αから放射される光が開口部１５に入射しないためには、（式２０）、或いは（式２１）、或いは（式２２）の条件を満たすよう光学系を設計する必要がある。（式２０）、（式２１）、（式２２）で与えられるＬ３だけ、開口部１５を屈折レンズ１３の焦点からずらして設置することで、プローブ１から放射される赤外線は開口部１５から筐体１４に入射することはなく、赤外受光素子３で受光せずに、鼓膜および／またはその近傍から発せられプローブ１の開口を通過した赤外線のみが開口部１５から入射して赤外受光素子３で受光させることができる。したがってプローブ１からの赤外線を遮る導波管は不要となる。また、プローブ１からの熱を受ける導波管がないため、屈折レンズ１３に高い熱伝導率の材質を使用する必要がない。
【０１３９】
以上の実施例１〜４において、屈折レンズ１３は、例えばポリエチレン等のような１０μｍ前後の波長の赤外線を透過する合成樹脂を用いる。ポリエチレンの熱物性値は、熱伝導率λが０．３４Ｊ／ｍｓＫ、熱容量は２．１２×１０⁶ Ｊ／ｋｇＫ、である。参考までに金属体の、たとえば銅の物性値を掲載すると熱伝導率λが３９８Ｊ／ｍｓＫ、熱容量は３．４３×１０⁶Ｊ／ｋｇＫ、となり、合成樹脂の熱伝導率が小さくまた熱容量が小さいことがわかる。
【０１４０】
この時、低温の室内に放置されていた放射体温計を高温の室内に持ち込むと、低温の屈折レンズ１３を含む受光部９が、その周囲の空気を冷却し露点以下になる状態が過渡的に発生する。
【０１４１】
しかし、屈折レンズ１３は、熱容量が小さいので表面の温度が上昇しやすく、また熱伝導率が小さいので表面の熱が厚さ方向に拡散しない。よって、屈折レンズ１３の表面が露点以下になったとしてもその時間は短く、結露は発生しにくい。したがって、放射体温計の周囲の温度が変化した場合でも結露の影響がない正確な温度検出が可能な構成である。
【０１４２】
以上、受光部の集光素子として屈折レンズを用いた例を説明したが、透過型回折レンズを用いても同様に赤外受光素子を配置することにより鼓膜および／またはその近傍から発せられプローブ１の開口を通過した赤外線のみが開口部１５から筐体１４に入射し赤外受光素子３で受光させることができる他、レンズの成形が容易という効果がある。
【０１４３】
（実施例５）
次に本発明の実施例５を図８を用いて説明する。図８は本発明の実施例５における放射体温計の受光部およびプローブを示す構成図である。ここで集光素子１３は前記実施例と異なり、集光ミラーを用いている。図８において、１はプローブ、３は赤外受光素子で、反射率の高い金属により構成された筐体１４に内蔵され、筐体１４には赤外線が入射する開口部１５が設けられている。１６は遮光体である。α、α’は集光ミラー１３の縁からこの縁と光軸に対して同じ側のプローブ１内壁へ接する直線がプローブ１の先端面と交わる仮想先端点、Ｆは集光ミラー１３の焦点、Ｆα、Ｆα’はそれぞれ集光ミラー１３によるα、α’の像点、Ｋ１αはαから光軸に対して同じ側の集光ミラー１３の縁で反射してＦαへ進行する光（マージナル光線）の光路、Ｋ２αはαから光軸と平行に進んで焦点Ｆを通過してＦαに到達する光の光路、Ｋ３αはαから集光ミラー１３の中心で反射してＦαに到達する光の光路、Ｋ４αはαから光軸を挟んで反対側の集光ミラー１３の縁で反射してＦαに到達する光（マージナル光線）の光路、Ｋ１α’はα’から光軸に対して同じ側の集光ミラー１３の縁で反射してＦα’へ進行する光（マージナル光線）の光路、Ｋ２α’はα’から光軸と平行に進んで焦点Ｆを通過してＦα’に到達する光の光路、Ｋ３α’はα’から集光ミラー１３の中心で反射してＦα’に到達する光の光路、Ｋ４α’はα’から光軸を挟んで反対側の集光ミラー１３の縁で反射してＦα’に到達する光（マージナル光線）の光路、ＦＸは光路Ｋ１αと光軸との交点である。
【０１４４】
プローブ１の開口を通過する赤外線のみが筐体１４の開口部１５に入射するような光学系を設計する。
【０１４５】
筐体１４を遮光体１６内部に設け、集光ミラー１３で反射しない赤外線は筐体１４が受光しないようにする。集光ミラーで反射した赤外線のみ受光する構成にした上で以下の設計を行う。
【０１４６】
鼓膜および／またはその近傍から発せられプローブ１の開口を通過した赤外光のみを受光するためには、プローブ１から放射される赤外光を受光しないようにすればよい。そのため、受光したい領域と受光したくない領域の境界に位置する点を仮想し、この点から、光軸に対してこの仮想した境界に位置する点と同じ側の集光ミラー１３の縁で反射する光（マージナル光線）の光路よりも、光軸から遠くに位置するようにプローブ１を設置すればよい。そこで、上記仮想の境界に位置する点を、集光ミラー１３の縁からこの縁と光軸に対して同じ側のプローブ１内壁へ接する直線がプローブ１の先端面と交わる点α、α’として、ＦαとＦα’とＦＸで形成される三角形の内側に開口部１５を設置する。これにより、プローブ１をαと集光ミラー１３の間で光路Ｋ１α、Ｋ１α’よりも光軸から遠くに位置させることになるため、プローブ１からの光を受光しない光学系が得られる。
【０１４７】
上記について詳細を以下に述べる。αから放射される光は光路Ｋ１α、Ｋ２α、Ｋ３α、Ｋ４αなどを通ってαの像点Ｆαに到達する。幾何光学で周知の通り、αの像点Ｆαは光軸を挟んでαと反対側に形成される。図８中に示すように、光路Ｋ２αを通る光は、集光ミラー１３で反射してＦで光軸と交叉したのち光軸から離れながらＦαに到達する。同じように、光路Ｋ１αを通る光は、集光ミラー１３で反射して光軸と交叉したのち光軸から離れながらＦαに到達する。光路Ｋ３αを通る光は、集光ミラー１３で光軸と交叉したのち光軸から離れながらＦαに到達する。光路Ｋ４αを通る光は、光軸と交叉して集光ミラー１３で反射し、集光ミラー１３で反射してからは光軸と交叉せずにＦαに到達する。このように、光路Ｋ１αと光軸が交叉する点ＦＸよりも集光ミラー１３から離れた位置かつＦαよりも集光ミラー１３に近い位置で、αから放射される光が通過しない領域が存在する。同じように、α’についても、光路Ｋ１α’と光軸が交叉する点よりも集光ミラー１３から離れた位置かつＦα’よりも集光ミラー１３に近い位置で、α’から放射される光が通過しない領域が存在する。この、Ｆα、Ｆα’、ＦＸで形成される三角形の内側よりに開口部１５を設置することで、α、α’から放射される光を受光しない受光部が得られる。
【０１４８】
αと集光ミラー１３の間の光路Ｋ１αより光軸から遠い部分からの光は、αと同じ面内で光軸からの距離がαより大きい点からの光と置き換えられる。この点の集光ミラー１３による像点はＦαよりも光軸から遠くなることは幾何光学で周知の通りである。そのため、αからの光を受光しないようにすれば、αよりも光軸から遠い点からの光を受光せず、従ってプローブ１からの光を受光しない。同様に、α’と集光ミラー１３の間の光路Ｋ１α’より光軸から遠い部分からの光は、α’と同じ面内で光軸からの距離がα’より大きい点からの光と置き換えられる。この点の集光ミラー１３による像点はＦα’よりも光軸から遠くなることは幾何光学で周知の通りである。そのため、α’からの光を受光しないようにすれば、α’よりも光軸から遠い点からの光を受光せず、従ってプローブ１からの光を受光しない。
【０１４９】
このように、ＦαとＦα’とＦＸで形成される三角形の内側に開口部１５を設置することでα、α’から放射される赤外線が開口部１５に入射しないようにすれば、自動的にプローブ１から放射される赤外線も開口部１５から筐体１４には入射せず赤外受光素子３では受光しない構成となる。
【０１５０】
以下、αからの光を受光しないような開口部１５の位置を求める。
【０１５１】
開口部１５はＦαよりも集光ミラー１３に近い。この時、（式１）が成り立ち、したがって（式２）が成り立つ。ここでＬαＦは集光ミラー１３の中心からαの像点Ｆαまでの距離、ｆは集光ミラー１３の中心から焦点Ｆまでの距離、Ｌ３は焦点Ｆから開口部１５までの距離である。
【０１５２】
図８に示すように、受光面は光路Ｋ１αと光軸が交わる点ＦＸとＦαとの間であるので、αからＦαまでの各光路のうち受光面で開口部１５に最も近づくものはＫ１αである。したがって、αからの光が開口部１５に入射しないためには、（式３）を満たす必要がある。ここで、ｒαＳ１は光路Ｋ１αと開口部１５の受光面との交点ＦαＳ１から光軸までの距離、ｒＳは開口部１５の半径である。また集光ミラー１３の半径をｒ３、光軸から像点Ｆαまでの距離をｒαＦとしたとき、幾何光学で周知の通りｒ３、ｒαＦ、ｒαＳ１、Ｌ３、ｆは幾何関係として（式４）を満たし、したがって（式５）を満たす。また（式５）を（式３）へ代入することで（式６）が得られる。（式２）、（式６）から、αから放射される光が開口部１５に入射しないための条件は（式７）となる。
【０１５３】
さらにαから光軸までの距離をｒα、プローブ１の先端から集光ミラー１３の中心までの距離をＬαとしたときに、幾何光学で周知の通り、ｒα、Ｌα、ｒαＦ、ＬαＦは幾何関係として（式８）を満たし、したがって、（式９）を満たす。（式９）を（式７）へ代入することにより、αから放射される光が開口部１５に入射しないための条件は（式１０）となる。また、ガウスの公式から（式１１）が成り立ち、したがって、（式１２）が成り立つ。（式１２）を（式１０）に代入することにより、αから放射される光が開口部１５に入射しないための条件は（式１３）となる。
【０１５４】
以上のように、プローブ１先端のαから放射される光が開口部１５に入射しないためには、（式７）、或いは（式１０）、或いは（式１３）を満たすよう光学系を設計する必要がある。（式７）、（式１０）、（式１３）で与えられるＬ３だけ、開口部１５を集光ミラー１０の焦点からずらして設置することで、プローブ１から放射される赤外線は開口部１５に入射せずに、鼓膜および／またはその近傍から発せられプローブ１の開口を通過した赤外線のみが開口部１５から筐体１４に入射して赤外受光素子３で受光させることができる。
【０１５５】
（実施例６）
次に本発明の実施例６を図９に基づいて説明する。図９は本発明の実施例６における放射体温計の受光部およびプローブを示す構成図である。図９において、１はプローブ、１３は集光ミラー、３は赤外受光素子で、反射率の高い金属により構成された筐体１４に内蔵され、筐体１４には赤外線が入射する開口部１５が設けられている。１６は遮光体である。α、α’は集光ミラー１３の縁からこの縁と光軸に対して同じ側のプローブ１内壁へ接する直線がプローブ１の先端面と交わる仮想先端点、Ｆは集光ミラー１３の焦点、Ｆα、Ｆα’はそれぞれ集光ミラー１３によるα、α’の像点、Ｋ１αはαから光軸に対して同じ側の集光ミラー１３の縁で反射してＦαへ進行する光（マージナル光線）の光路、Ｋ２αはαから光軸と平行に進んで焦点Ｆを通過してＦαに到達する光の光路、Ｋ３αはαから集光ミラー１３の中心で反射してＦαに到達する光の光路、Ｋ４αはαから光軸を挟んで反対側の集光ミラー１３の縁で反射してＦαに到達する光（マージナル光線）の光路、Ｋ１α’はα’から光軸に対して同じ側の集光ミラー１３の縁を通過してＦα’へ進行する光（マージナル光線）の光路、Ｋ２α’はα’から光軸と平行に進んで焦点Ｆを通過してＦα’に到達する光の光路、Ｋ３α’はα’から集光ミラー１３の中心で反射してＦα’に到達する光の光路、Ｋ４α’はα’から光軸を挟んで反対側の集光ミラー１３の縁で反射してＦα’に到達する光（マージナル光線）の光路、ＦＸは光路Ｋ１αと光軸との交点である。
【０１５６】
プローブ１の開口を通過する赤外線のみが開口部１５に入射ような光学系を設計する。
【０１５７】
筐体１４を遮光体１６内部に設け、集光ミラー１３で反射する赤外線のみが開口部１５に入射するようにする。集光ミラー１３で反射した赤外線のみ入射する構成にした上で以下の設計を行う。
【０１５８】
鼓膜および／またはその近傍から発せられプローブ１の開口を通過した赤外光のみを受光するためには、プローブ１から放射される赤外光を受光しないようにすればよい。そのため、受光したい領域と受光したくない領域の境界に位置する点を仮想し、この点から、光軸に対してこの仮想した境界に位置する点と同じ側の集光ミラー１３で反射する光（マージナル光線）の光路よりも、光軸から遠くに位置するようにプローブ１を設置すればよい。そこで、上記仮想の境界に位置する点を、集光ミラー１３の縁からこの縁と光軸に対して同じ側のプローブ１内壁へ接する直線がプローブ１の先端面と交わる点α、α’として、Ｆαよりも集光ミラー１３から遠い部分の光路Ｋ４αと、Ｆα’よりも集光ミラー１３から遠い部分の光路Ｋ４α’で挟まれた領域に開口部１５を設置する。これにより、プローブ１をαと集光ミラー１３の間で光路Ｋ１α、Ｋ１α’よりも光軸から遠くに位置させることになるため、プローブ１からの光を受光しない光学系が得られる。
【０１５９】
上記について詳細を以下に述べる。
【０１６０】
αから放射される光は光路Ｋ１α、Ｋ２α、Ｋ３α、Ｋ４αなどを通ってαの像点Ｆαに到達する。幾何光学で周知の通り、αの像点Ｆαは光軸を挟んでαと反対側に形成される。図９中に示すように、光路Ｋ２αを通る光は、集光ミラー１３で反射してＦで光軸と交叉してＦαに到達し光軸から離れていく。同じように、光路Ｋ１αを通る光は、集光ミラー１３で反射して光軸と交叉してＦαに到達し光軸から離れていく。光路Ｋ３αを通る光は、集光ミラー１３で光軸と交叉してＦαに到達し光軸から離れていく。光路Ｋ４αを通る光は、光軸と交叉して集光ミラー１３で反射し、集光ミラー１３で反射してからは光軸と交叉せずにＦαに到達し、その後光軸に近づくかあるいは遠ざかっていく。このように、αの像点Ｆαよりも集光ミラー１３から離れた位置でαから放射される光が通過しない領域が存在する。同じようにα’についても、αの像点Ｆαよりも集光ミラー１３から離れた位置でαから放射される光が通過しない領域が存在する。この、Ｆαよりも集光ミラー１３から遠い部分の光路Ｋ４αと、Ｆα’よりも集光ミラー１３から遠い部分の光路Ｋ４α’で挟まれた領域内に赤外受光素子３を設置することによってα、α’から放射される赤外線を受光しない受光部が得られる。αと集光ミラー１３の間の光路Ｋ１αより光軸から遠い部分からの光は、αと同じ面内で光軸からの距離がαより大きい点からの光と置き換えられる。この点の集光ミラー１３による像点はＦαよりも光軸から遠くなることは幾何光学で周知の通りである。そのため、αからの光を受光しないようにすれば、αよりも光軸から遠い点からの光を受光せず、従ってプローブ１からの光を受光しない。同様に、α’と集光ミラー１３の間の光路Ｋ１α’より光軸から遠い部分からの光は、α’と同じ面内で光軸からの距離がα’より大きい点からの光と置き換えられる。この点の集光ミラー１３による像点はＦα’よりも光軸から遠くなることは幾何光学で周知の通りである。そのため、α’からの光を受光しないようにすれば、α’よりも光軸から遠い点からの光を受光せず、従ってプローブ１からの光を受光しない。
【０１６１】
このように、Ｆαよりも集光ミラー１３から遠い部分の光路Ｋ４αと、Ｆα’よりも集光ミラー１３から遠い部分の光路Ｋ４α’で挟まれた領域に開口部１５を設置することでα、α’から放射される赤外線が入射しないようにすれば、自動的にプローブ１から放射される赤外線も開口部１５から筐体１４に入射せず赤外受光素子３で受光しない構成となる。
【０１６２】
以下、αからの光を受光しないような開口部１５の位置を求める。
【０１６３】
開口部１５はＦαよりも集光ミラー１３から遠い。この時、（式１４）が成り立ち、したがって（式１５）が成り立つ。ここでＬαＦは集光ミラー１３の中心からαの像点Ｆαまでの距離、ｆは集光ミラー１３の中心から焦点Ｆまでの距離、Ｌ３は焦点Ｆから開口部１５までの距離である。
【０１６４】
図９に示すように、受光面はＦαよりも集光ミラー１３から遠いので、αからＦαまでの各光路のうち受光面で赤外受光素子３に最も近づくものはＫ４αである。したがって、αからの光を赤外受光素子３で受光しないためには、（式１６）を満たす必要がある。ここで、ｒαＳ４は光路Ｋ４αと赤外受光素子３の受光面との交点ＦαＳ４から光軸までの距離、ｒＳは開口部１５の半径である。また集光ミラー１３の半径をｒ３、光軸から像点Ｆαまでの距離をｒαＦとしたとき、幾何光学で周知の通りｒ３、ｒαＦ、ＬαＦ、ｒαＳ４、Ｌ３、ｆは幾何関係として（式１７）を満たし、したがって（式１８）を満たす。（式１８）を（式１６）へ代入することで（式１９）が得られる。（式１５）、（式１９）から、αから放射される光が開口部１５に入射しないための条件は（式２０）となる。
【０１６５】
さらにαから光軸までの距離をｒα、プローブ１の先端から集光ミラー１３の中心までの距離をＬαとしたときに、幾何光学で周知の通り、ｒα、Ｌα、ｒαＦ、ＬαＦは幾何関係として（式８）を満たし、したがって（式９）を満たす。（式９）を（式２０）へ代入することにより、αから放射される光が開口部１５に入射しないための条件は（式２１）となる。また、ガウスの公式から（式１１）が成り立つので、（式１２）が成り立つ。（式１２）を（式２１）に代入することにより、αから放射される光が開口部１５に入射しないための条件は（式２２）となる。
【０１６６】
以上のように、αから放射される光が開口部１５に入射しないためには、（式２０）、或いは（式２１）、或いは（式２２）の条件を満たすよう光学系を設計する必要がある。（式２０）、（式２１）、（式２２）で与えられるＬ３だけ、開口部１５を集光ミラー１３の焦点からずらして設置することで、プローブ１から放射される赤外線は開口部１５に入射せずに、鼓膜および／またはその近傍から発せられプローブ１の開口を通過した赤外線のみを開口部１５に入射させることができる。
【０１６７】
（実施例７）
次に本発明の実施例７を図１０を用いて説明する。図１０は集光素子として集光ミラーを用いた例において、集光ミラーに入射する第１の光軸と反射して集光ミラーから出射する第２の光軸を屈曲させた例を示す。１３は集光素子としての凹面鏡でその焦点はＦにある。このうちの一部太線で示すＡ〜Ａ’の部分のみを切り出して集光ミラーとして使うことにより、この中心を通る光軸は一点鎖線で示すように屈曲させて使うことができるようになる。ここで赤外受光素子３は開口部１５を持った筐体１４の内部に設けていて、集光ミラー１３の焦点Ｆより後方に、詳細には前記した実施例で示す範囲に配置すればよい。
【０１６８】
放射体温計の使いやすさを考慮すると、図１に戻ってプローブ１と本体５を約１１５度屈曲させるのが好ましい。それは本体５を手で持って、プローブ１を外耳道に挿入する場合、自然な手の位置で体温測定できる角度が約１１５度だからである。したがって、図１０において光軸を約１１５度屈曲させる構成をとると受光部は本体に収納しやすくなる。また自然な手の位置で体温測定することで、プローブを外耳道に挿入する方向は安定しやすくなり、体温の測定精度も向上させることができる。
【０１６９】
前記実施例５〜７において集光ミラー１３の材料は、実施例１〜４で説明した屈折レンズと異なり、赤外線を透過させる必要がない。例えば、集光ミラー１３の材料としてここでは、ポリプロピレン，ポリカーボネイトを用い、その表面に金属の蒸着またはメッキを施した構成とする。ポリプロピレンの物性値は、熱伝導率λが０．１２Ｊ／ｍｓＫ、熱容量は１．７６×１０⁶ Ｊ／ｋｇＫ、である。またポリカーボネイトの物性値は、熱伝導率λが０．１９Ｊ／ｍｓＫ、熱容量は１．５１×１０⁶ Ｊ／ｋｇＫ、であり、双方とも屈折レンズの例で説明したポリエチレンと同様に十分小さい。
【０１７０】
この構成により、プローブ１から放射される赤外線を開口部１５から筐体１４に入射させずに鼓膜および／またはその近傍からの放射光のみを入射させ、赤外受光素子３で受光させることができるので、集光素子１３が被測定物から伝わる熱の影響を受け難く、光学系に高い熱伝導性を必要としない。そして、集光素子は、熱容量と熱伝導率が小さいので、屈折レンズの例と同様に、温度が変化した場合でも結露の影響がない正確な温度検出が可能な構成とすることができる。
【０１７１】
ただし、集光ミラーに用いる材質としてはポリプロピレン，ポリカーボネイト，ポリエチレンに限られるものではない。
【０１７２】
以上、受光部の集光素子として集光ミラーを用いた例を説明したが、これは屈折レンズを使う場合に比べ、透過損失がなく受光量を増大させる効果がある。また、反射型回折レンズを用いても同様に開口部１５を配置することにより鼓膜および／またはその近傍から発せられプローブ１の開口を通過した赤外線のみを開口部１５から筐体１４に入射させて赤外受光素子３で受光させることができる他、ミラーの成形が容易という効果がある。
【０１７３】
前記の各実施例において、集光素子１３で透過または反射し、開口部１５に入射しないプローブ１の内面からの赤外線は、遮光体１６の内面に入射することになる。しかし、この遮光体１６の内面は反射抑制手段であるため、入射した赤外線が反射して開口部１５に入射するようなことはない。従って、測定誤差の要因となるプローブ１からの赤外線放射が開口部１５から筐体１４に入射し赤外受光素子３が受光するのを確実に阻止し、正確な温度検出ができる。
【０１７４】
遮光体１６は、例えばＰＣ、ＰＰＳ、ＰＢＴ、ＰＰ等のような合成樹脂を用いる。一般にこれら合成樹脂の放射率は０．９前後と高い値になることが知られている。また、物体に入射する赤外線は、反射成分と吸収成分と透過成分に分けられるが、透過のない場合を考えると、反射率と吸収率の和は１になる。ここでキルヒホッフの法則より、放射率と吸収率は等しいので、結果として放射率の高い合成樹脂は反射率が低いということが言える。従って、これらの合成樹脂を使用して遮光体１６を構成することで、遮光体１６自体が反射抑制手段となり、赤外受光素子３以外の位置へ進行した不要な赤外線が、遮光体１６で反射して赤外受光素子３に入射してしまうことがない。従って、受光領域を制限しプローブ１からの不要な赤外線を赤外受光素子３に入射させない作用を完全なものとすることができる。
【０１７５】
また、遮光体１６は赤外線の透過の小さい合成樹脂を用い、また赤外線が透過しないだけの充分な厚さを持たせて設計することは言うまでもない。また、遮光体１６を合成樹脂とすることにより、集光素子と同様の原理により遮光体１６にも結露が発生しにくい。もし遮光体１６が金属ならば、遮光体１６に発生した結露が移動することにより集光素子１３に付着し、その結果、集光能力を低下させる可能性があり、また遮光体１６に発生した結露により赤外光が散乱して開口部１５から赤外受光素子３にプローブ１から放射された赤外光が入射する可能性もあるが、遮光体１６が樹脂ならば結露が発生しないためそのようなことがない。
【０１７６】
また、以上説明した集光素子１３と開口部１５の配置で、プローブから放射される赤外線が開口部１５に至らない範囲内でプローブの形状を変えることは可能であり、図３に示した長さ方向の寸法の違いだけでなく、径の違う複数のプローブを備えてもよい。特に長さ方向の寸法を短くすれば、同じ集光素子と赤外受光素子の配置で径を細くでき、幼児に対応しやすいプローブも備えることができる効果がある。
【０１７７】
以上の各実施例において赤外受光素子３はその出力が対象物との温度差に相関のあるサーモパイル型であればそのままの構成で使えば良く、赤外受光素子３の出力が測定対象の温度変化に対して相関のある焦電型であれば、入射する赤外線を強制的に変化させるチョッパを設ければよい。
【０１７８】
以上の各実施例において筐体１４の開口部１５を適切な位置に配置することで、赤外受光素子３の大きさには無関係に鼓膜および／またはその近傍から放射される赤外光のみを受光することができるようになるの。即ち、実施例において説明した範囲が非常に小さな領域しかなく、それに対して赤外受光素子３が大きい場合でも、開口部１５の面積を小さくするだけで赤外受光素子３は鼓膜および／またはその近傍から放射された赤外光のみを受光することができる。ここで筐体１４は反射率の高い金属にすることで簡易な構成にできる。ただし、材料を樹脂にしてその内面を金属で蒸着、またはメッキしても良い。また、内面の反射率を高くするのは開口部１５から入射する赤外光が筐体内面で反射しながら赤外受光素子３に入射するようにして、赤外受光素子３においての受光量を増大させるためである。内面が黒体の場合には開口部１５から入射した直接光のみが赤外受光素子３に入射するので、赤外受光素子３の感度が十分大きく実用上の問題がなければ筐体１４の内面の反射率を高くしなくても良い。
【０１７９】
【発明の効果】
以上説明したように本発明の放射体温計は以下の効果を有する。
【０１８０】
本発明の請求項１にかかる放射体温計によれば、受光部は鼓膜および／またはその近傍から放射されプローブを通過した赤外線のみを受光し、信号処理手段は受光部からの出力を温度に演算し、演算結果の温度を報知手段が報知する。そして受光部の筐体の開口部には集光素子で集光された赤外線が入射し、開口部に入射した赤外線は赤外受光素子に入射することで、鼓膜および／またはその近傍から放射されプローブを通過した放射光のみをスポット的に検出することが可能となり、正確な検温ができる。
【０１８１】
本発明の請求項２にかかる放射体温計によれば、本体に収納された受光部は鼓膜および／またはその近傍から発せられプローブを通過した赤外線のみを受光し、プローブは内部に導波管がなく空洞状態にして本体に着脱自在に連結しているので、導波管の温度変動による温度精度の悪化がなく、プローブ交換により衛生上の問題がなくかつプローブをはずせば突出部分がなく収納が容易になる。
【０１８２】
本発明の請求項３にかかる放射体温計によれば、プローブは先端が開口しているので、先端を覆うカバーの赤外線透過率のばらつきによる温度誤差要因が無くなり、測定温度精度を向上できる。
【０１８３】
本発明の請求項４にかかる放射体温計によれば、非計測時には収納部にプローブが収納されるので、本体は収納しやすい形状になり、かつはずしたプローブを紛失する可能性は少なくなる。
【０１８４】
本発明の請求項５にかかる放射体温計によれば、目視で判別可能な複数のプローブを備えているのでプローブごとに使用者を特定することは可能でプローブ交換による感染の問題がない。
【０１８５】
本発明の請求項６にかかる放射体温計によれば、鼓膜および／またはその近傍から直接放射される赤外線のみを受光する受光部からの出力に基づいて演算した温度を音声報知手段を有する報知手段で報知するので、耳に挿入している時間に拘わらず正確な体温を測定することができる。
【０１８６】
本発明の請求項７にかかる放射体温計によれば、集光素子外からの赤外線が筐体に入射するのを遮る遮光体を有し、遮光体の筐体側に反射抑制手段を設けたので、筐体の開口部以外の位置へ進行した赤外線が反射して筐体の内部に入射してしまうことがない。従って、受光領域を制限し、鼓膜および／またはその近傍以外からの赤外線を筐体の開口部以外の点へ導くので、プローブの温度変化の影響を受けず正確な体温測定ができる。
【０１８７】
本発明の請求項８にかかる放射体温計によれば、一般に合成樹脂の放射率は０．９前後と高い値になることが知られていて、これを遮光体として用いることで赤外線の反射が抑制される。また、合成樹脂は熱伝導率が低く、かつ熱容量が小さいので、遮光体表面に結露が発生しにくい。したがって、結露による赤外線の反射や散乱がなく正確な体温測定ができる。
【０１８８】
本発明の請求項９にかかる放射体温計によれば、プローブからの赤外線を遮る導波管は不要であり、集光素子を含む光学系に高い熱伝導率を必要としない。そして、集光素子は熱伝導率が低く、かつ熱容量が小さい材質より構成したので、集光素子表面に結露が発生しにくく正確な体温測定ができる。
本発明の請求項１０にかかる放射体温計によれば、一般に合成樹脂は熱伝導率が低く熱容量が小さいことが知られており、合成樹脂により集光素子表面の結露を抑制することができる。
【０１８９】
本発明の請求項１１にかかる放射体温計によれば、筐体には集光素子で集光された赤外線が入射し、また筐体の開口部はは仮想先端点と同じ側の集光素子の縁を通過して集光素子による仮想先端点の像点へ到達する光路と光軸との交点よりも集光素子から遠く且つ集光素子による仮想先端点の像点よりも集光素子に近い領域に設置することで、プローブ内壁から集光素子に入射する赤外線を筐体の開口部以外の位置へ進行させることができ、受光領域を制限することができる。そして筐体の開口部から入射した赤外線が赤外受光素子に入射するので、赤外受光素子の大きさにかかわらず鼓膜および／またはその近傍から放射されプローブを通過した放射光のみをスポット的に検出することが可能となる。
【０１９０】
本発明の請求項１２にかかる放射体温計によれば、筐体には集光素子で集光された赤外線が入射し、また筐体の開口部は仮想先端点と同じ側の集光素子の縁を通過して集光素子による仮想先端点の像点へ到達する光路と光軸との交点と、集光素子による仮想先端点の２つの像点とで形成される、集光素子の子午面内の三角形内に設置することで、プローブ内壁から集光素子に入射する赤外線を筐体の開口部以外の位置へ進行させることができ、受光領域を制限することができる。そして筐体の開口部から入射した赤外線が赤外受光素子に入射するので、赤外受光素子の大きさにかかわらず鼓膜および／またはその近傍から放射されプローブを通過した放射光のみをスポット的に検出することが可能となる。
【０１９１】
本発明の請求項１３にかかる放射体温計によれば、筐体には集光素子で集光された赤外線が入射し、また筐体の開口部は集光素子の焦点距離ｆと、筐体の開口部の半径ｒＳと、仮想先端点と光軸との距離ｒαと、仮想先端点と集光素子との距離Ｌαと、集光素子の半径ｒ３を用いて、（式１３）で与えられるＬ３だけ集光素子の焦点よりも集光素子から遠くに設置することで、プローブ内壁から集光素子に入射する赤外線を筐体の開口部以外の位置へ進行させることができ、受光領域を制限することができる。そして筐体の開口部に入射した赤外線が赤外受光素子に入射するので、赤外受光素子の大きさにかかわらず鼓膜および／またはその近傍から放射されプローブを通過した放射光のみをスポット的に検出することが可能となる。
【０１９２】
本発明の請求項１４にかかる放射体温計によれば、筐体には集光素子で集光された赤外線が入射し、また筐体の開口部を、集光素子の縁から光軸に対して前記集光素子の縁と同じ側のプローブの内壁に接するように引いた直線が前記プローブの先端の面と交叉する仮想先端点の集光素子による像点よりも前記集光素子から遠い領域に設置することで、プローブ内壁から集光素子に入射する赤外線を筐体の開口部以外の位置へ進行させることができ、受光領域を制限することができる。そして筐体の開口部に入射した赤外線が赤外受光素子に入射するので、赤外受光素子の大きさにかかわらず鼓膜および／またはその近傍から放射されプローブを通過した放射光のみをスポット的に検出することが可能となる。
【０１９３】
本発明の請求項１５にかかる放射体温計によれば、筐体には集光素子で集光された赤外線が入射し、また筐体の開口部を、集光素子の縁から光軸に対して前記集光素子の縁と同じ側のプローブの内壁に接するように引いた直線が前記プローブの先端の面と交叉する仮想先端点から光軸を挟んで前記仮想先端点と反対側の前記集光素子の縁を通過して前記集光素子による前記仮想先端点の像点へ到達する前記集光素子の子午面内の２つの光路で挟まれた領域に設置することで、プローブ内壁から集光素子に入射する赤外線を筐体の開口部以外の位置へ進行させることができ、受光領域を制限することができる。そして筐体の開口部に入射した赤外線が赤外受光素子に入射するので、赤外受光素子の大きさにかかわらず鼓膜および／またはその近傍から放射されプローブを通過した放射光のみをスポット的に検出することが可能となる。
【０１９４】
本発明の請求項１６にかかる放射体温計によれば、筐体には集光素子で集光された赤外線が入射し、また筐体の開口部は集光素子の焦点距離ｆと、筐体の開口部の半径ｒＳと、仮想先端点と光軸との距離ｒαと、仮想先端点と前記集光素子との距離Ｌαと、集光素子の半径ｒ３を用いて、（式２２）で表されるＬ３だけ前記集光素子の焦点よりも集光素子から遠くに設置することで、プローブ内壁から集光素子に入射する赤外線を筐体の開口部以外の位置へ進行させることができ、受光領域を制限することができる。そして筐体の開口部に入射した赤外線が赤外受光素子に入射するので、赤外受光素子の大きさにかかわらず鼓膜および／またはその近傍から放射されプローブを通過した放射光のみをスポット的に検出することが可能となる。
【０１９５】
本発明の請求項１７にかかる放射体温計によれば、屈折レンズにより筐体の開口部には集光された赤外線が入射する。
【０１９６】
本発明の請求項１８にかかる放射体温計によれば、集光ミラーにより、筐体の開口部には集光された赤外線が入射する。
【０１９７】
本発明の請求項１９にかかる放射体温計によれば、外耳道に挿入して測定する放射体温計としての使い勝手を考慮しプローブと本体を屈曲させたとき、この角度に併せて光学系も屈曲させることができる。従って、使い勝手がよく、耳孔に挿入しやすくなることで挿入方向が安定しやすく精度よく体温測定ができる。
【０１９８】
本発明の請求項２０にかかる放射体温計によれば、筐体の内面を反射率の高い材料とすることで、赤外受光素子には筐体の開口部から入射する赤外線を反射させながら有効に入射させることができる。
本発明の請求項２１にかかる放射体温計によれば、金属は一般に反射率が高いので、筐体を簡易に構成できる。
【図面の簡単な説明】
【図１】本発明の実施例１の放射体温計の構成図
【図２】（ａ）〜（ｄ）同実施例の異なる記号を印刷した複数のプローブの側面図
【図３】（ａ）〜（ｄ）同実施例の寸法の異なる複数のプローブの側面図
【図４】同実施例の受光部およびプローブの構成図
【図５】本発明の実施例２の受光部およびプローブを示す構成図
【図６】本発明の実施例３の受光部およびプローブを示す構成図
【図７】本発明の実施例４の受光部およびプローブを示す構成図
【図８】本発明の実施例５の受光部およびプローブを示す構成図
【図９】本発明の実施例６の受光部およびプローブを示す構成図
【図１０】本発明の実施例７の集光素子の構成図
【図１１】従来例の放射体温計の構成ブロック図
【符号の説明】
１ プローブ
３ 赤外受光素子
４ 信号処理手段
５ 本体
７ 収納部
９ 受光部
１０ 報知手段
１２ 音声報知手段
１３ 集光素子
１４ 筐体
１５ 開口部
１６ 遮光体（反射抑制手段）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a radiation thermometer that measures the body temperature of a living body by detecting the amount of infrared rays emitted from the ear canal.
[0002]
[Prior art]
Conventionally, as a thermometer, there is a radiation thermometer that detects the amount of infrared rays emitted from the ear canal in a non-contact manner and converts the body temperature, and these can be measured in a short time against a contact type using mercury or a thermocouple. There is a feature.
[0003]
A general example of this type of thermometer will be described with reference to FIG. As shown in FIG. 11, the radiation thermometer includes a probe 1, a waveguide 2 that runs in the length direction in the probe 1, and an infrared light receiving device that converts infrared radiation intensity propagated in the waveguide 2 into an electrical signal. An element 3 and signal processing means 4 for measuring temperature from the converted electric signal are provided.
[0004]
By inserting the probe 1 into the ear canal, the infrared light receiving element 3 receives infrared rays emitted from the eardrum and / or the vicinity thereof, outputs an electrical signal correlated with the amount of received infrared rays, and signal processing means 4 Converts the temperature of the eardrum and / or the vicinity thereof from the electrical signal.
[0005]
In general, the infrared light receiving element 3 outputs an electrical signal having a correlation with the total amount of infrared light incident from all directions, and the waveguide 2 is made of at least an inner surface made of metal, or subjected to a plating process. Therefore, the reflectance is increased. In this configuration, the infrared rays emitted from the eardrum and / or the vicinity thereof are reflected directly or multiple times on the inner surface of the waveguide 2 to reach the infrared light receiving element 3. Further, unnecessary infrared light emitted from the inner surface of the probe 1 does not reach the infrared light receiving element 3.
[0006]
However, it is difficult to make the inner surface of the waveguide 2 a complete reflector (reflectance = 1), and light incident by multiple reflection causes a reflection loss due to the nth power of the reflectivity. In addition, reflection at a shallow angle such as a single reflection generally has a lower reflectance than vertical light, and a reflection loss also occurs. In the portion corresponding to these reflection losses, infrared radiation emitted from the waveguide 2 is incident on the infrared light receiving element 3, and if there is a temperature variation of the waveguide 2 when the probe 1 is inserted into the ear canal, it is red. The external light receiving element 3 is affected by this and cannot accurately measure the body temperature.
[0007]
In the above-described conventional example, in order to solve this problem, the tip of the probe 1 is made thinner than the trunk portion to reduce the contact with the ear canal, thereby reducing the temperature fluctuation of the waveguide 2. In the example shown in Japanese Patent Laid-Open No. 5-45229, the probe surface is made of a heat insulating material and the inside is made of a highly thermally conductive material so that it is less affected by the heat from the ear canal and the received heat is quickly received by infrared light. The device is designed to cancel the influence by conducting heat to the element. In the example shown in Japanese Patent Application Laid-Open No. 8-126615, the probe is made detachable, and the probe is exchanged for each measurement so that the influence of heat accumulated in the probe is removed.
[0008]
[Problems to be solved by the invention]
However, none of the above methods is perfect to accurately measure the temperature of the eardrum and / or the vicinity thereof by eliminating the influence of heat transmitted from the ear canal to the waveguide. There is a problem that the body temperature measurement is not accurate. In particular, when the measurement is repeatedly performed at short intervals, the temperature of the waveguide gradually changes, and the measurement temperature gradually changes even for the same subject under the influence.
[0009]
In order to reduce the influence of the measurement error due to this problem, when a metal is used as the high thermal conductivity material for the waveguide, there is a problem that condensation easily occurs inside the waveguide in a low temperature environment. This is because the temperature of the metal surface does not rise easily even when touching air close to body temperature by inserting it into the ear canal in a low temperature environment. Accordingly, the vapor containing water vapor is cooled by a metal having a dew point or lower, and condensation occurs on the metal surface. When this dew condensation phenomenon occurs in a part that has the function of reflecting infrared rays, such as a waveguide, infrared rays are absorbed and scattered by dew condensation, and the infrared rays that reach the infrared light receiving element are significantly reduced. Become.
[0010]
In addition, when an unspecified number of people use such a radiation thermometer, in general, from the aspect of hygiene management, it is common to attach a sanitary cover to the probe, insert it into the ear canal, replace the sanitary cover and throw it away. . This sanitary cover must be closed with a membrane at the part that contacts the probe tip. This is because the tip of the waveguide extends to the tip of the probe, and it is necessary to provide a film at the tip in order to prevent dirt from adhering to the waveguide.
[0011]
On the other hand, if there are a small number of subjects, such as at home or a small number of people, it is possible to prevent infection from the ears by deciding the probe to be used for each individual. Consumption can be eliminated. However, even in this case, it is necessary to close the tip of the probe with an infrared transmitting material film in order to prevent dirt from adhering to the waveguide.
[0012]
In any case, the amount of infrared rays transmitted through the film provided at the probe tip is measured due to hygiene problems. Here, when infrared rays pass through the film, there are components that absorb or reflect, and it is difficult to completely transmit the infrared rays. The infrared transmittance of this film varies depending on the thickness of the film, etc. Even if it is adjusted with a specific film attached, there is a problem that a temperature error occurs due to dispersion of the transmittance when another film is attached. There is.
[0013]
Further, by notifying the measurement temperature by voice, there is an effect that the measurement result can be understood even when used by a blind person or when measuring in the dark. For example, it is disclosed in JP-A-6-142061. Methods are known.
[0014]
However, for example, if the end of measurement is notified by a beep sound, 0.1 to 0.2 seconds is sufficient, but if the temperature is notified by voice, it takes 2 to 3 seconds. In other words, when the radio thermometer having the above-described configuration is used for sound notification, the probe must be continuously inserted into the ear until the notification is finished, and the heat of the ear is transmitted to the waveguide during that time, causing a temperature change. However, when the measurement is repeated, there is a problem that the temperature change of the waveguide during the notification time appears as a measurement error in the next measurement.
[0015]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a probe that is inserted into the ear canal and that passes infrared rays emitted from the eardrum and / or its vicinity, a light-receiving unit that receives infrared light that has passed through the probe, and an output of the light-receiving unit Signal processing means for calculating the temperature of the signal processing means, and notification means for reporting the output of the signal processing means. The light receiving unit is an infrared light receiving element, and the infrared light receiving element is provided therein and an opening for receiving infrared rays. And a condensing element that collects at least infrared rays that have passed through the probe, and the opening of the casing is disposed rearward from the focal position of the condensing element, thereby reducing the light receiving region. This is a limited configuration.
[0016]
According to the above invention, the light receiving unit receives only infrared rays radiated from the eardrum and / or its vicinity and passed through the probe, the signal processing unit calculates the output from the light receiving unit to the temperature, and notifies the temperature of the calculation result Will inform you. Infrared light collected by the light converging element is incident on the opening of the housing of the light receiving unit. The infrared light incident on the opening is incident on the infrared light receiving device, and is emitted from the eardrum and / or the vicinity thereof. Only the emitted light that has passed through the probe can be spot-detected, and accurate temperature detection can be performed.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
A radiation thermometer according to claim 1 of the present invention includes a probe that is inserted into the ear canal and transmits infrared rays emitted from the eardrum and / or its vicinity, a light receiving unit that receives infrared light that has passed through the probe, It comprises signal processing means for calculating the output to temperature and notifying means for notifying the output of the signal processing means, and the light receiving section is provided with an infrared light receiving element and an opening through which the infrared light receiving element is provided. And a light collecting region that collects at least the infrared light that has passed through the probe, and the opening of the housing is disposed rearward from the focal position of the light collecting device. Is limited.
[0018]
The light receiving unit receives only infrared rays emitted from the eardrum and / or its vicinity and passed through the probe, the signal processing unit calculates the output from the light receiving unit to the temperature, and the notification unit notifies the temperature of the calculation result. Infrared light collected by the light converging element is incident on the opening of the housing of the light receiving unit. The infrared light incident on the opening is incident on the infrared light receiving device, and is emitted from the eardrum and / or the vicinity thereof. Only the emitted light that has passed through the probe can be spot-detected, and accurate temperature detection can be performed.
[0019]
A radiation thermometer according to a second aspect of the present invention has a main body that houses a light receiving portion, and the probe is connected to the main body in a hollow state to be detachable.
[0020]
The light receiving unit housed in the main body receives only the infrared rays emitted from the eardrum and / or its vicinity and passed through the probe, and the probe is detachably connected to the main body without a waveguide inside. Therefore, there is no deterioration in temperature accuracy due to temperature fluctuations of the waveguide, and there is no sanitary problem by exchanging the probe.
[0021]
In the radiation thermometer according to claim 3 of the present invention, the probe has a configuration in which the tip is opened.
[0022]
Since the tip of the probe is open, the temperature error factor due to the variation in the infrared transmittance of the cover covering the tip is eliminated, and the measurement temperature accuracy can be improved.
[0023]
According to a fourth aspect of the present invention, the main body has a housing portion for housing the probe when not measuring.
[0024]
Since the probe is housed in the housing portion during non-measurement, the main body has a shape that can be easily housed, and the possibility of losing the removed probe is reduced.
[0025]
The radiation thermometer according to claim 5 of the present invention has a configuration in which a plurality of probes are provided and each has a difference that can be visually discriminated.
[0026]
Since a plurality of probes that can be visually discriminated are provided, it is possible to specify a user for each probe and there is no problem of infection due to probe replacement.
[0027]
In the radiation thermometer according to claim 6 of the present invention, the notifying means has voice notifying means for notifying the temperature of the calculation result of the signal processing means by voice.
[0028]
And since the temperature calculated based on the output from the light receiving unit that receives only infrared rays directly emitted from the eardrum and / or its vicinity is notified by the notification means having the voice notification means, it is possible to insert the temperature into the ear. Regardless, accurate body temperature can be measured.
[0029]
In the radiation thermometer according to claim 7 of the present invention, the light receiving portion has a light shielding body that blocks infrared rays from outside the light collecting element from entering the opening of the housing, and the opening of the housing of the light shielding body. A reflection suppressing means is provided on the side.
[0030]
In addition, the infrared ray that has traveled to a position other than the opening of the casing because the reflection suppressing means is provided on the casing side of the light shielding body. Is not reflected and incident on the inside of the housing. Therefore, the light receiving area is limited, and infrared rays from other than the eardrum and / or the vicinity thereof are guided to a point other than the opening of the housing, so that accurate body temperature measurement can be performed without being affected by the temperature change of the probe.
[0031]
The radiation thermometer according to claim 8 of the present invention uses a synthetic resin as a material of the light shielding body.
[0032]
In general, it is known that the emissivity of a synthetic resin is as high as about 0.9. By using this as a light shielding body, reflection of infrared rays is suppressed. Further, since the synthetic resin has a low thermal conductivity and a small heat capacity, condensation is unlikely to occur on the surface of the light shielding body. Therefore, the body temperature can be accurately measured without reflection or scattering of infrared rays due to condensation.
[0033]
In the radiation thermometer according to claim 9 of the present invention, the condensing element is made of a material having a low thermal conductivity and a small heat capacity.
[0034]
In addition, a waveguide that blocks infrared rays from the probe is unnecessary, and high optical conductivity is not required for the optical system including the condensing element. And since the condensing element was comprised from the material with low heat conductivity and a small heat capacity, it is hard to produce dew condensation on the condensing element surface, and an accurate body temperature measurement can be performed.
[0035]
The radiation thermometer according to claim 10 of the present invention uses a synthetic resin as a material of the condensing element.
[0036]
In general, it is known that synthetic resins have a low thermal conductivity and a small heat capacity, and the condensation on the surface of the light collecting element can be suppressed by the synthetic resin.
[0037]
The radiation thermometer according to claim 11 of the present invention is a straight line in which the opening of the housing is drawn from the edge of the light condensing element so as to contact the inner wall of the probe on the same side as the edge of the light condensing element with respect to the optical axis. Passes through the edge of the condensing element on the same side as the virtual tip point from the virtual tip point intersecting the surface of the tip of the probe and reaches the image point of the virtual tip point by the condensing element It is installed in a region farther from the condensing element than the intersection of the optical path and the optical axis, and closer to the condensing element than the image point of the virtual tip point by the condensing element.
[0038]
Infrared rays collected by the condensing element are incident on the casing, and the opening of the casing passes through the edge of the condensing element on the same side as the virtual leading end point and the virtual leading end point by the condensing element. Focusing from the inner wall of the probe by installing it in a region farther from the condensing element than the intersection of the optical path reaching the image point and the optical axis and closer to the condensing element than the image point of the virtual tip point by the condensing element Infrared light incident on the element can be advanced to a position other than the opening of the housing, and the light receiving area can be limited. Since infrared light incident from the opening of the housing is incident on the infrared light receiving element, it is possible to spot-detect only the radiated light emitted from the eardrum and / or its vicinity and passing through the probe.
[0039]
The radiation thermometer according to claim 12 of the present invention is a straight line in which the opening of the housing is drawn from the edge of the light collecting element so as to contact the inner wall of the probe on the same side as the edge of the light collecting element with respect to the optical axis. Passes through the edge of the condensing element on the same side as the virtual tip point from the virtual tip point intersecting the surface of the tip of the probe and reaches the image point of the virtual tip point by the condensing element It is installed in a triangle in the meridian plane of the condensing element, which is formed by the intersection of the optical path and the optical axis and the two image points of the virtual tip point by the condensing element.
[0040]
Infrared rays collected by the condensing element are incident on the casing, and the opening of the casing passes through the edge of the condensing element on the same side as the virtual leading end point, and the virtual leading end point by the condensing element. The probe inner wall is installed in a triangle in the meridian plane of the condensing element formed by the intersection of the optical path reaching the image point and the optical axis and the two image points of the virtual tip point by the condensing element. Infrared rays incident on the light condensing element can be advanced to positions other than the opening of the housing, and the light receiving area can be limited. Since infrared light incident from the opening of the housing is incident on the infrared light receiving element, it is possible to spot-detect only the radiated light emitted from the eardrum and / or its vicinity and passing through the probe.
[0041]
According to a thirteenth aspect of the present invention, there is provided the radiation thermometer, wherein the opening of the housing is arranged with respect to the optical axis from the focal length f of the light collecting element, the radius rS of the opening of the housing, and the edge of the light collecting device. The distance rα between the virtual tip point and the optical axis where the straight line drawn so as to contact the inner wall of the probe on the same side as the edge of the light collecting element intersects the surface of the probe tip, the virtual tip point and the light collecting point Using the distance Lα to the element and the radius r3 of the condensing element,
[0042]
[Equation 3]

[0043]
The distance L3 given by (2) is set farther from the condensing element than the focal point of the condensing element.
[0044]
Infrared rays collected by the condensing element are incident on the casing, and the opening of the casing has a focal length f of the condensing element, a radius rS of the opening of the casing, a virtual tip point, and light. Using the distance rα to the axis, the distance Lα between the virtual tip point and the condensing element, and the radius r3 of the condensing element, the distance L3 given by the above equation is farther from the condensing element than the focal point of the condensing element. The infrared rays incident on the light collecting element from the inner wall of the probe can be advanced to a position other than the opening of the housing, and the light receiving area can be limited. Since the infrared light incident on the opening of the housing is incident on the infrared light receiving element, it is possible to spot-detect only the radiated light emitted from the eardrum and / or its vicinity and passing through the probe.
[0045]
The radiation thermometer according to claim 14 of the present invention is a straight line in which the opening of the housing is drawn from the edge of the condensing element so as to contact the inner wall of the probe on the same side as the edge of the condensing element with respect to the optical axis. Is installed in a region farther from the light condensing element than the image point by the light condensing element at the virtual tip point intersecting the surface of the probe tip.
[0046]
Infrared light collected by the condensing element is incident on the casing, and the opening of the casing is connected to the optical axis from the edge of the condensing element on the same side as the edge of the condensing element. By installing the straight line drawn so as to contact the inner wall in a region farther from the light condensing element than the image point of the light condensing element at the virtual tip point intersecting the surface of the tip of the probe, Incident infrared rays can be advanced to positions other than the opening of the housing, and the light receiving area can be limited. Since the infrared light incident on the opening of the housing is incident on the infrared light receiving element, it is possible to spot-detect only the radiated light emitted from the eardrum and / or its vicinity and passing through the probe.
[0047]
The radiation thermometer according to claim 15 of the present invention is a straight line in which the opening of the casing is drawn from the edge of the light collecting element so as to contact the inner wall of the probe on the same side as the edge of the light collecting element with respect to the optical axis. Passes through the edge of the condensing element on the opposite side of the virtual tip point across the optical axis from the virtual tip point intersecting the surface of the tip of the probe to the image point of the virtual tip point by the condensing element It is installed in a region sandwiched between two optical paths in the meridian plane of the condensing element that reaches.
[0048]
Infrared light collected by the condensing element is incident on the casing, and the opening of the casing is connected to the optical axis from the edge of the condensing element on the same side as the edge of the condensing element. The straight line drawn so as to contact the inner wall passes through the edge of the light condensing element on the opposite side of the virtual tip point across the optical axis from the virtual tip point intersecting the surface of the tip of the probe. By installing in a region sandwiched between two optical paths in the meridian plane of the light condensing element that reaches the image point of the virtual tip point, infrared rays incident on the light condensing element from the inner wall of the probe other than the opening of the housing The light receiving area can be limited. Since the infrared light incident on the opening of the housing is incident on the infrared light receiving element, it is possible to spot-detect only the radiated light emitted from the eardrum and / or its vicinity and passing through the probe.
[0049]
According to a sixteenth aspect of the present invention, in the radiation thermometer, the opening of the casing is arranged with respect to the optical axis from the focal length f of the condensing element, the radius rS of the opening of the casing, and the edge of the condensing element. The distance rα between the virtual tip point and the optical axis where the straight line drawn so as to contact the inner wall of the probe on the same side as the edge of the light collecting element intersects the surface of the tip of the probe, the virtual tip point and the Using the distance Lα to the condensing element and the radius r3 of the condensing element,
[0050]
[Expression 4]

[0051]
The distance L3 represented by is set farther from the condensing element than the focal point of the condensing element.
[0052]
Infrared rays collected by the condensing element are incident on the casing, and the opening of the casing has a focal length f of the condensing element, a radius rS of the opening of the casing, a virtual tip point, and light. Using the distance rα to the axis, the distance Lα between the virtual tip point and the light condensing element, and the radius r3 of the light condensing element, the light is condensed from the focal point of the light condensing element by L3 represented by the above formula. By installing the sensor far from the element, infrared light incident on the light collecting element from the inner wall of the probe can be advanced to a position other than the opening of the housing, and the light receiving area can be limited. Since the infrared light incident on the opening of the housing is incident on the infrared light receiving element, it is possible to spot-detect only the radiated light emitted from the eardrum and / or its vicinity and passing through the probe.
[0053]
In the radiation thermometer according to claim 17 of the present invention, the condensing element is constituted by a refractive lens.
[0054]
The condensed infrared light is incident on the opening of the housing by the refractive lens.
[0055]
In the radiation thermometer according to claim 18 of the present invention, the condensing element is constituted by a condensing mirror.
[0056]
Then, the condensed infrared light is incident on the opening of the housing by the condensing mirror.
[0057]
According to a nineteenth aspect of the present invention, in the radiation thermometer, the condensing mirror includes a first optical axis incident on the condensing mirror, and a second light emitted from the condensing mirror and incident on an opening of the housing. The shaft is bent.
[0058]
When the probe and the main body are bent in consideration of usability as a radiation thermometer that is inserted into the ear canal and measured, the optical system can be bent in accordance with this angle. Therefore, it is easy to use and easy to insert into the ear canal, so that the insertion direction is easy to stabilize and the body temperature can be measured accurately.
[0059]
In a radiant thermometer according to claim 20 of the present invention, at least the inner surface of the casing is made of a highly reflective material.
[0060]
In addition, by using a highly reflective material for the inner surface of the housing, the infrared light receiving element can be effectively incident while reflecting the infrared light that is incident from the opening of the housing.
[0061]
In the radiation thermometer according to claim 21 of the present invention, the casing is made of metal.
[0062]
And since a metal generally has a high reflectance, a housing | casing can be comprised simply.
[0063]
【Example】
(Example 1)
Embodiment 1 of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram of a radiation thermometer of the present invention. 2 to 3 are side views of a plurality of probes, and FIG. 4 is a configuration diagram of a light receiving unit and probes.
[0064]
In FIG. 1, reference numeral 1 denotes a probe that is inserted into the ear canal when measuring body temperature, and has a shape narrowed toward the distal end toward the eardrum. The distal end is open, and the body 5 can be attached to and detached from the opposite end. As shown in FIG. When the probe 1 is attached to the main body 5, the protrusion 6 is distorted inward by the pressing force and attached to the main body 5. When removing, the probe 1 is similarly distorted inward by pressing the probe 1 with a finger. The main body 5 has a storage portion 7. When the body temperature is not measured, the probe 1 is removed and stored in the storage portion 7. The storage unit 7 includes a lid 8 that opens and closes when stored. By removing the probe 1 at the time of non-measurement, it becomes the shape of the main body itself and becomes a shape that can be easily stored. Moreover, since the removed probe 1 is stored in the storage unit 7, there is little possibility of losing it.
[0065]
9 is a light receiving unit that receives only the infrared light that has passed through the opening of the probe 1 and outputs an electrical signal corresponding to the amount of the infrared light. 4 is a signal processing means for converting the temperature based on a signal input from the light receiving unit 9. The temperature converted here is an infrared irradiation source temperature, and corresponds to the temperature of the eardrum and / or the vicinity thereof.
[0066]
The temperature converted by the signal processing means 4 is notified to the user by the notification means 10 as the body temperature. The notification means 10 includes number display means 11 and voice notification means 12 for displaying the body temperature converted by the signal processing means 4 in numbers. The number display means 11 is, for example, a liquid crystal display, and the voice notification means 12 is, for example, a speaker.
[0067]
Here, as will be described in detail later, the light receiving unit 9 receives only the infrared light that has passed through the opening of the probe 1 and therefore is not affected by temperature fluctuations of the probe 1 and does not require a waveguide. The probe 1 is detachable and has a plurality of probes, for example, as shown in FIG. In FIG. 2, “A” is printed in (a), “B” is printed in (b), “C” is printed in (c), and “D” is printed in (d). For example, if you are using it at home, if you have a family of four, you can decide which probe to use for each individual, so that you can avoid infection from the ear without making a mistake as the symbol becomes a landmark. Further, since the waveguide 1 is not provided, the tip portion of the probe 1 may be opened and is not covered with a film, so there is no temperature error due to variations in the infrared transmittance of the film.
[0068]
As a method of providing a difference that can be visually determined so as not to make a mistake in the probe used for each individual, in addition to the difference in the symbols described above, a color may be changed or a different pattern may be printed. Further, the dimensions may be changed as shown in FIG. In FIG. 3, (a) is the shortest and (b), (c), and (d) are made longer in this order. In this case, in addition to the correct probe to be used due to the difference that can be visually judged, for infants with small ears (a), for adults with large ears, use (d) for the dimensions that are most easily inserted into the ear. There is also an effect that it can be selected.
[0069]
Further, since the voice notification means 12 performs voice notification, the temperature measurement result can be known even when measurement is performed in the dark or when a person with a blind eye is measuring. Moreover, since the number display means 11 also notifies, it is possible to know the temperature measurement result even when measuring in a noisy environment or when measuring by a person with hearing impairment. Since the temperature is measured with the ear, the voice notification means 12 can notify the subject with a sufficiently small volume so that only the subject can hear the temperature measurement result, and other than the subject can not hear the temperature measurement result. There is no trouble with unnecessary noise. It also protects the subject's privacy.
[0070]
The configuration of the light receiving unit 9 will be described with reference to FIG. In FIG. 4, reference numeral 13 denotes a refractive lens that is a condensing element, and reference numeral 3 denotes an infrared light receiving element, which is built in a case 14 made of a highly reflective metal, and an opening 15 through which infrared rays enter the case 14. Is provided. Reference numeral 16 denotes a light shield. At least the inner surface of the light shielding body 16 is constituted by a reflection suppressing means having a low reflectance such as a synthetic resin described in detail later. A and A ′ are intersections of a straight line drawn from the edge of the refractive lens 13 so as to be in contact with the inner wall of the probe 1 on the same side as this edge and the tip end surface of the probe 1. If the probe is a linear probe, it is a point located on the inner wall of the tip of the probe 1. B is a point on the inner wall of the probe 1, that is, a point of a region that is not desired to be received, F is a focal point of the refractive lens 13, FA is an A image point by the refractive lens 13, FA ′ is an A ′ image point by the refractive lens 13, FB is an image point of B by the refractive lens 13, K1A is an optical path of light (marginal ray) that travels from A to the FA through the edge of the refractive lens 13 on the same side as the optical axis, and K2A is an optical axis from A , K3A is the optical path of light that passes through the center of the refractive lens 13 and reaches the FA, and K4A is opposite from the A across the optical axis. This is an optical path of light (marginal light) that passes through the edge of the refractive lens 13 on the side and reaches the FA. Similarly, K1A ′ is an optical path of light (marginal light) traveling from A ′ to the FA ′ through the edge of the refractive lens 13 on the same side as the optical axis, and K2A ′ is parallel to the optical axis from A ′. The optical path of light that travels through the focal point F and reaches FA ′, K3A ′ is the optical path of light that passes through the center of the refractive lens 13 from A ′ and reaches FA ′, and K4A ′ is the optical axis from A ′. An optical path of light (marginal ray) that passes through the edge of the refractive lens 13 on the opposite side and reaches FA ′, K3B is an optical path of light that passes through the center of the refractive lens 13 from B and reaches FB, FX is This is the intersection of the optical path K1A and the optical path K1A ′.
[0071]
An optical system is designed such that only infrared rays that pass through the opening of the probe 1 enter the opening 15 of the housing 14.
[0072]
The housing 14 is attached to the light shield 16 so that the housing 14 does not receive infrared rays that do not pass through the refractive lens 13. The following design is performed after only the infrared ray that passes through the refractive lens 13 is received.
[0073]
The light emitted from A reaches the image point FA of A through the optical paths K1A, K2A, K3A, K4A and the like. As is well known in geometric optics, the image point FA of A is formed on the opposite side of A across the optical axis. As shown in FIG. 4, the light passing through the optical path K2A passes through the refractive lens 13, crosses the optical axis at F, and then reaches the FA while leaving the optical axis. Similarly, the light passing through the optical path K1A passes through the refractive lens 13 and crosses the optical axis, and then reaches the FA while leaving the optical axis. The light passing through the optical path K3A crosses the optical axis by the refractive lens 13 and then reaches the FA while leaving the optical axis. The light passing through the optical path K4A crosses the optical axis and passes through the refractive lens 13, and after passing through the refractive lens 13, reaches the FA without crossing the optical axis. Thus, there is a region through which light emitted from A does not pass at a position farther from the refractive lens 13 than the point FX where the optical path K1A and the optical axis intersect, and closer to the refractive lens 13 than FA. This region is inside the triangle formed by FX, FA, and FA ′. By installing the opening 15 of the housing 14 inside the triangle, the light radiated from A and A ′ is not incident on the inside of the housing 14 and the light receiving unit that is not received by the infrared light receiving element 3 is provided. can get.
[0074]
As point B in the region of the inner wall of the probe 1 that is not desired to receive light is farther from the optical axis than A, it is well known that the image point FB of B by the refractive lens 13 is farther from the optical axis than FA. Therefore, by setting the opening 15 of the housing 14 inside the triangle formed by FX, FA, and FA ′, if infrared rays radiated from A and A ′ are prevented from entering the inside of the housing 14, The infrared light from B is not automatically incident, and the infrared light receiving element 3 does not receive light.
[0075]
As described above, by installing the opening 15 of the housing 14 inside the triangle formed by FX, FA, and FA ′, the region of the vicinity of the optical axis that is desired to receive light, that is, the eardrum that has passed through the opening of the probe 1 and / or Alternatively, a light receiving portion in which only the infrared light emitted from the vicinity thereof is received by the infrared light receiving element 3 can be obtained.
[0076]
(Example 2)
Next, Embodiment 2 of the present invention will be described with reference to FIG. FIG. 5 is a configuration diagram showing a light receiving portion and a probe of a radiation thermometer in Embodiment 2 of the present invention. In FIG. 5, reference numeral 13 denotes a refractive lens, and reference numeral 3 denotes an infrared light receiving element, which is built in a case 14 made of a highly reflective metal, and the case 14 is provided with an opening 15 through which infrared rays are incident. . Reference numeral 16 denotes a light shield. A and A ′ are intersections between a straight line drawn from the edge of the refractive lens 13 so as to contact the inner wall of the probe 1 and the surface of the tip of the probe 1, and the distance from the opening to the body mounting portion is linear as shown in FIG. If it is a simple probe, it is a point located on the inner wall of the tip of the probe 1. B is a point on the inner wall of the probe 1, that is, a point of a region that is not desired to be received, F is a focal point of the refractive lens 13, FA is an A image point by the refractive lens 13, FA ′ is an A ′ image point by the refractive lens 13, FB is an image point of B by the refractive lens 13, K1A is an optical path of light (marginal ray) that travels from A to the FA through the edge of the refractive lens 13 on the same side as the optical axis, and K2A is an optical axis from A , K3A is the optical path of light that passes through the center of the refractive lens 13 and reaches the FA, and K4A is opposite from the A across the optical axis. An optical path of light (marginal ray) that passes through the edge of the refractive lens 13 on the side (marginal ray), K1A ′ passes from the edge of the refractive lens 13 on the same side to the optical axis from A ′ and proceeds to FA ′. Light (marginal ray), K2A 'is light from A' An optical path of light traveling parallel to the axis and passing through the focal point F and reaching FA ′, K3A ′ is an optical path of light passing from A ′ to the center of the refractive lens 13 and reaches FA ′, and K4A ′ is A ′. , The optical path of light (marginal ray) that passes through the edge of the refractive lens 13 on the opposite side across the optical axis and reaches FA ′, K3B passes through the center of the refractive lens 13 from B and reaches FB An optical path, K4B, an optical path of light (marginal ray) that passes through the edge of the refractive lens 13 on the opposite side across the optical axis from B and reaches FB, FX is an intersection of the optical path K1A and the optical path K1A ′, and FY is an optical path K4A. And the optical path K4A ′.
[0077]
An optical system is designed such that only infrared rays that pass through the opening of the probe 1 enter the opening 15 of the housing 14.
The housing 14 is attached to the light shield 16 so that the housing 14 does not receive infrared rays that do not pass through the refractive lens 13. The following design is performed after only the infrared ray that passes through the refractive lens 13 is received.
[0078]
The light emitted from A reaches the image point FA of A through the optical paths K1A, K2A, K3A, K4A and the like. As is well known in geometric optics, the image point FA of A is formed on the opposite side of A across the optical axis. As shown in FIG. 5, the light passing through the optical path K2A passes through the refractive lens 13, crosses the optical axis at F, reaches FA, and moves away from the optical axis. Similarly, the light passing through the optical path K1A passes through the refractive lens 13, crosses the optical axis, reaches the FA, and moves away from the optical axis. The light passing through the optical path K3A crosses the optical axis by the refractive lens 13 and reaches the FA and leaves the optical axis. The light passing through the optical path K4A crosses the optical axis and passes through the refractive lens 13, and after passing through the refractive lens 13, reaches the FA without crossing the optical axis, and then approaches or moves away from the optical axis. Go.
[0079]
Thus, there is a region where light emitted from A does not pass at a position farther from the refractive lens than the image point FA of A. This region is a region sandwiched by a portion of the optical path K4A farther from the refractive lens 13 than FA and a portion of the optical path K4A 'farther from the refractive lens 13 than FA ′. By installing the opening 15 of the housing 14 in this region, the light emitted from A and A ′ does not enter the inside of the housing 14 and a light receiving portion that is not received by the infrared light receiving element 3 is obtained. .
[0080]
As point B in the region of the inner wall of the probe 1 that is not desired to receive light is farther from the optical axis than A, it is well known that the image point FB of B by the refractive lens 13 is farther from the optical axis than FA. Therefore, by installing the opening 15 of the housing 14 in a region sandwiched by the optical path K4A at a portion farther from the refractive lens 13 than FA and the optical path K4A 'at a portion farther from the refractive lens 13 than FA ′, A If the infrared rays radiated from A ′ are not incident on the inside of the housing 14, the infrared rays from B are not automatically incident and the infrared light receiving element 3 does not receive light.
[0081]
As described above, the opening 15 of the housing 14 is installed in a region sandwiched between the optical path K4A at a portion farther from the refractive lens 13 than FA and the optical path K4A 'at a portion farther from the refractive lens 13 than FA ′. As a result, a light receiving section is obtained in which the infrared light receiving element 3 receives only the infrared light emitted from the region near the optical axis, that is, the eardrum that has passed through the opening of the probe 1 and / or the vicinity thereof.
[0082]
(Example 3)
Next, Embodiment 3 of the present invention will be described with reference to FIG. FIG. 6 is a configuration diagram showing a light receiving portion and a probe of a radiation thermometer in Embodiment 3 of the present invention. Here, unlike the embodiment, the probe 1 has an R-attached portion so that it can be easily inserted into the ear canal. In FIG. 6, reference numeral 13 denotes a refractive lens, and reference numeral 3 denotes an infrared light receiving element, which is built in a case 14 made of a highly reflective metal, and the case 14 is provided with an opening 15 through which infrared rays are incident. . Reference numeral 16 denotes a light shield. α, α ′ are virtual tip points where a straight line contacting the inner wall of the probe 1 on the same side as the edge and the optical axis from the edge of the refractive lens 13 intersects the tip surface of the probe 1, F is the focal point of the refractive lens 13, Fα, Fα ′ is the image point of α and α ′ by the refraction lens 13, K1α is the optical path of light (marginal light) that passes from the edge of the refraction lens 13 on the same side to the optical axis and travels to Fα, K2α Is the optical path of light traveling parallel to the optical axis from α and passing through the focal point F to reach Fα, K3α is the optical path of light passing from α to the center of the refractive lens 13 and reaches Fα, and K4α is light from α An optical path of light (marginal ray) that passes through the edge of the refractive lens 13 on the opposite side across the axis and reaches Fα, K1α ′ passes through the edge of the refractive lens 13 on the same side with respect to the optical axis from α ′. The optical path of light (marginal light) traveling to Fα ′, K2α ′ is the optical axis from α ′. The optical path of light that goes to the line and passes through the focal point F and reaches Fα ′, K3α ′ is the optical path of light that passes through the center of the refractive lens 13 from α ′ and reaches Fα ′, and K4α ′ is the light path from α ′. An optical path of light (marginal ray) that passes through the edge of the refractive lens 13 on the opposite side across the axis and reaches Fα ′, FX is an intersection of the optical path K1α and the optical axis.
[0083]
An optical system is designed such that only infrared rays that pass through the opening of the probe 1 enter the opening 15 of the housing 14.
[0084]
The housing 14 is attached to the light shield 16 so that the housing 14 does not receive infrared rays that do not pass through the refractive lens 13. The following design is performed after only the infrared ray that passes through the refractive lens 13 is received.
[0085]
In order to allow only infrared light emitted from the eardrum and / or its vicinity and passing through the opening of the probe 1 to enter the opening 15 of the housing 14, the infrared light emitted from the probe 1 is not received. You can do it. For this reason, a point located at the boundary between the region where light is desired to be received and the region where light is not desired is assumed, and from this point, the point passes through the edge of the refractive lens 13 on the same side as the point located at the virtual boundary. What is necessary is just to install the probe 1 so that it may be located far from an optical axis rather than the optical path of light (marginal light beam). Therefore, the points located at the imaginary boundary are defined as points α and α ′ where the straight line contacting the inner wall of the probe 1 on the same side as the edge and the optical axis from the edge of the refractive lens 13 intersects the tip surface of the probe 1. The opening 15 of the housing 14 is installed inside a triangle formed by Fα, Fα ′, and FX. As a result, the probe 1 is positioned farther from the optical axis than the optical paths K1α and K1α ′ between α and the refractive lens 13, so that an optical system that does not receive light from the probe 1 is obtained.
[0086]
Details of the above will be described below. The light emitted from α reaches the image point Fα of α through the optical paths K1α, K2α, K3α, K4α and the like. As is well known in geometrical optics, the image point Fα of α is formed on the opposite side of α across the optical axis. As shown in FIG. 6, the light passing through the optical path K2α passes through the refractive lens 13, crosses the optical axis at F, and then reaches Fα while leaving the optical axis. Similarly, the light passing through the optical path K1α passes through the refractive lens 13 and crosses the optical axis, and then reaches Fα while leaving the optical axis. The light passing through the optical path K3α crosses the optical axis by the refractive lens 13 and then reaches Fα while leaving the optical axis. The light passing through the optical path K4α crosses the optical axis and passes through the refractive lens 13, and then passes through the refractive lens 13 and reaches Fα without crossing the optical axis. Thus, there is a region where light emitted from α does not pass at a position farther from the refractive lens 13 than the point FX where the optical path K1α and the optical axis intersect, and closer to the refractive lens 13 than Fα. Similarly, with respect to α ′, light emitted from α ′ passes at a position farther from the refractive lens 13 than the point where the optical path K1α ′ intersects the optical axis and closer to the refractive lens 13 than Fα ′. There is an area that does not. By installing the opening 15 of the housing 14 from the inside of the triangle formed by Fα, Fα ′, and FX, the light receiving unit in which the infrared light receiving element 3 does not receive the light emitted from α, α ′. Is obtained. Light from a portion farther from the optical axis than the optical path K1α between α and the refractive lens 13 is replaced with light from a point whose distance from the optical axis is greater than α in the same plane as α. As is well known in geometrical optics, the image point by the refractive lens 13 at this point is farther from the optical axis than Fα. Therefore, if light from α is not received, light from a point farther from the optical axis than α is not received, and therefore light from the probe 1 is not received. Similarly, light from a portion farther from the optical axis than the optical path K1α ′ between α ′ and the refractive lens 13 is replaced with light from a point whose distance from the optical axis is larger than α ′ in the same plane as α ′. . As is well known in geometrical optics, the image point by the refractive lens 13 at this point is farther from the optical axis than Fα ′. Therefore, if light from α ′ is not received, light from a point farther from the optical axis than α ′ is not received, and therefore light from the probe 1 is not received.
[0087]
In this way, by setting the opening 15 of the housing 14 inside the triangle formed by Fα, Fα ′, and FX so that infrared rays radiated from α, α ′ are not incident, it is automatically performed. Infrared light radiated from the probe 1 does not enter the inside of the housing 14 and the infrared light receiving element 3 does not receive light.
[0088]
Hereinafter, the position of the opening 15 of the housing 14 that does not receive light from α is obtained.
[0089]
The opening 15 is closer to the refractive lens 13 than Fα. At this time, the following equation holds.
[0090]
LαF ≧ f + L3 (1)
Therefore
L3 ≦ LαF−f (2)
Here, LαF is the distance from the center of the refractive lens 13 to the α image point Fα, f is the distance from the center of the refractive lens 13 to the focal point F, and L3 is the distance from the focal point F to the opening 15.
[0091]
As shown in FIG. 6, since the light receiving surface is between the points FX and Fα where the optical path K1α and the optical axis intersect, the optical path from α to Fα that is closest to the opening 15 on the light receiving surface is K1α. is there. Therefore, in order that the light from α does not enter the opening 15, it is necessary to satisfy the following expression.
[0092]
rαS1> rS (3)
Here, rαS1 is the distance from the intersection FαS1 between the optical path K1α and the light receiving surface of the opening 15 to the optical axis, and rS is the radius of the opening 15. Further, assuming that the radius of the refractive lens 13 is r3 and the distance from the optical axis to the image point Fα is rαF, r3, rαF, rαS1, L3, and f satisfy (Expression 4) as a geometric relationship as is well known in geometric optics.
[0093]
[Equation 5]

[0094]
Therefore, (Equation 5) is satisfied.
[0095]
[Formula 6]

[0096]
(Expression 6) is obtained by substituting (Expression 5) into (Expression 3).
[0097]
[Expression 7]

[0098]
From (Expression 2) and (Expression 6), the condition for preventing the light emitted from α from entering from the opening 15 is (Expression 7).
[0099]
[Equation 8]

[0100]
Further, when the distance from α to the optical axis is rα, and the distance from the tip of the probe 1 to the center of the refractive lens 13 is Lα, as is well known in geometric optics, rα, Lα, rαF, and LαF have a geometric relationship ( Equation 8) is satisfied.
[0101]
[Equation 9]

[0102]
Therefore, (Equation 9) is satisfied.
[0103]
[Expression 10]

[0104]
By substituting (Equation 9) into (Equation 7), the condition for preventing the light emitted from α from entering through the opening 15 is (Equation 10).
[0105]
[Expression 11]

[0106]
Further, (Equation 11) holds from the Gauss formula.
[0107]
[Expression 12]

[0108]
Therefore, (Equation 12) holds.
[0109]
[Formula 13]

[0110]
By substituting (Equation 12) into (Equation 10), the condition for preventing the light emitted from α from entering from the aperture 15 is (Equation 13).
[0111]
[Expression 14]

[0112]
As described above, in order that the light emitted from α at the tip of the probe 1 does not enter the inside of the housing 14 through the opening 15 and is not received by the infrared light receiving element 3, (Expression 7) or (Expression 10) ) Or it is necessary to design the optical system so as to satisfy (Equation 13). Infrared rays radiated from the probe 1 are incident from the aperture 15 by disposing the aperture 15 away from the focus of the refractive lens 13 by L3 given by (Equation 7), (Equation 10), and (Equation 13). Instead, only infrared rays emitted from the eardrum and / or the vicinity thereof and having passed through the opening of the probe 1 can enter the opening 15 and be received by the infrared light receiving element 3.
[0113]
Example 4
Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 7 is a configuration diagram showing a light receiving portion and a probe of a radiation thermometer in Embodiment 4 of the present invention. In FIG. 7, reference numeral 1 denotes a probe having an R-attached portion as in the third embodiment. Reference numeral 13 denotes a refractive lens, and reference numeral 3 denotes an infrared light receiving element, which is built in a casing 14 made of a highly reflective metal, and the casing 14 is provided with an opening 15 through which infrared rays are incident. Reference numeral 16 denotes a light shield. α, α ′ are virtual tip points where a straight line contacting the inner wall of the probe 1 on the same side as the edge and the optical axis from the edge of the refractive lens 13 intersects the tip surface of the probe 1, F is the focal point of the refractive lens 13, Fα, Fα ′ is the image point of α and α ′ by the refractive lens 13, respectively, K1α is the optical path of light (marginal light) that passes through the edge of the refractive lens 13 on the same side from α and travels to Fα, K2α Is the optical path of light that travels parallel to the optical axis from α and passes through the focal point F and reaches Fα, K3α is the optical path of light that passes through the center of the refractive lens 13 from α and reaches Fα, and K4α is the light path from α An optical path of light (marginal ray) that passes through the edge of the refractive lens 13 on the opposite side across the axis and reaches Fα, K1α ′ passes through the edge of the refractive lens 13 on the same side with respect to the optical axis from α ′. The optical path of light (marginal light) traveling to Fα ′, K2α ′ is the optical axis from α ′. The optical path of light that goes to the line and passes through the focal point F and reaches Fα ′, K3α ′ is the optical path of light that passes through the center of the refractive lens 13 from α ′ and reaches Fα ′, and K4α ′ is the light path from α ′. An optical path of light (marginal ray) that passes through the edge of the refractive lens 13 on the opposite side across the axis and reaches Fα ′, FX is an intersection of the optical path K1α and the optical axis.
[0114]
An optical system is designed such that only infrared rays that pass through the opening of the probe 1 enter the opening 15 of the housing 14.
[0115]
The housing 14 is attached to the light shield 16 so that the housing 14 does not receive infrared rays that do not pass through the refractive lens 13. The following design is performed after only the infrared ray that passes through the refractive lens 13 is received.
[0116]
In order to receive only infrared light emitted from the eardrum and / or its vicinity and passing through the opening of the probe 1, it is only necessary not to receive infrared light emitted from the probe 1. For this reason, a point located at the boundary between the region where light is desired to be received and the region where light is not desired is assumed, and from this point, the point passes through the edge of the refractive lens 13 on the same side as the point located at the virtual boundary. What is necessary is just to install the probe 1 so that it may be located far from an optical axis rather than the optical path of light (marginal light beam). Therefore, the points located at the imaginary boundary are defined as points α and α ′ where the straight line contacting the inner wall of the probe 1 on the same side as the edge and the optical axis from the edge of the refractive lens 13 intersects the tip surface of the probe 1. The infrared light receiving element 3 is installed in a region sandwiched between a portion of the optical path K4α farther from the refractive lens 13 than Fα and a portion of the optical path K4α ′ farther from the refractive lens 13 than Fα ′. As a result, the probe 1 is positioned farther from the optical axis than the optical paths K1α and K1α ′ between α and the refractive lens 13, so that an optical system that does not receive light from the probe 1 is obtained.
[0117]
Details of the above will be described below.
[0118]
The light emitted from α reaches the image point Fα of α through the optical paths K1α, K2α, K3α, K4α and the like. As is well known in geometrical optics, the image point Fα of α is formed on the opposite side of α across the optical axis. As shown in FIG. 7, the light passing through the optical path K2α passes through the refractive lens 13, crosses the optical axis at F, reaches Fα, and moves away from the optical axis. Similarly, the light passing through the optical path K1α passes through the refractive lens 13, crosses the optical axis, reaches Fα, and moves away from the optical axis. The light passing through the optical path K3α crosses the optical axis by the refractive lens 13 and reaches Fα and moves away from the optical axis. The light passing through the optical path K4α crosses the optical axis and passes through the refractive lens 13. After passing through the refractive lens 13, it reaches Fα without crossing the optical axis, and then approaches or moves away from the optical axis. Go. In this way, there is a region where light emitted from α does not pass at a position farther from the refractive lens 13 than the image point Fα of α. Similarly, for α ′, there is a region through which light emitted from α ′ does not pass at a position farther from the refractive lens 13 than the image point Fα ′ of α ′. By installing the opening 15 in a region sandwiched between the optical path K4α in the portion farther from the refractive lens 13 than Fα and the optical path K4α ′ in the portion farther from the refractive lens 13 than Fα ′, the opening 15 is placed from α and α ′. A light receiving portion that does not receive the emitted infrared light is obtained. Light from a portion farther from the optical axis than the optical path K1α between α and the refractive lens 13 is replaced with light from a point whose distance from the optical axis is greater than α in the same plane as α. As is well known in geometrical optics, the image point by the refractive lens 13 at this point is farther from the optical axis than Fα. Therefore, if light from α does not enter the opening 15, light from a point farther from the optical axis than α does not enter, and therefore light from the probe 1 does not enter from the opening 15. Similarly, light from a portion farther from the optical axis than the optical path K1α ′ between α ′ and the refractive lens 13 is replaced with light from a point whose distance from the optical axis is larger than α ′ in the same plane as α ′. . As is well known in geometrical optics, the image point by the refractive lens 13 at this point is farther from the optical axis than Fα ′. Therefore, if light from α ′ is prevented from entering the opening 15, light from a point farther from the optical axis than α ′ does not enter, and therefore light from the probe 1 does not enter from the opening 15.
[0119]
In this way, α and α ′ are obtained by installing the opening 15 in a region sandwiched between the optical path K4α at a portion farther from the refractive lens 13 than Fα and the optical path K4α ′ at a portion farther from the refractive lens 13 than Fα ′. If the infrared rays emitted from the probe 1 are not incident, the infrared rays emitted from the probe 1 are not automatically incident and the infrared light receiving element 3 does not receive light.
[0120]
Hereinafter, the position of the opening 15 that does not receive light from α is obtained.
[0121]
The opening 15 is farther from the refractive lens 13 than Fα. At this time, the following equation holds.
[0122]
LαF ≦ f + L3 (14)
Therefore
L3 ≧ LαF−f (15)
Here, LαF is the distance from the center of the refractive lens 13 to the α image point Fα, f is the distance from the center of the refractive lens 13 to the focal point F, and L3 is the distance from the focal point F to the opening 15.
[0123]
As shown in FIG. 7, since the light receiving surface is farther from the refractive lens 13 than Fα, the light path closest to the opening 15 is K4α among the light paths from α to Fα. Therefore, in order that the light from α does not enter the opening 15, it is necessary to satisfy the following expression.
[0124]
rαS4> rS (16)
Here, rαS4 is the distance from the intersection FαS4 between the optical path K4α and the light receiving surface of the opening 15 to the optical axis, and rS is the radius of the opening 15. Further, when the radius of the refractive lens 13 is r3 and the distance from the optical axis to the image point Fα is rαF, as is well known in geometric optics, r3, rαF, LαF, rαS4, L3, and f are expressed as a geometrical relationship (Expression 17). Fulfill.
[0125]
[Expression 15]

[0126]
Therefore, (Equation 18) is satisfied.
[0127]
[Expression 16]

[0128]
(Equation 19) is obtained by substituting (Equation 18) into (Equation 16).
[0129]
[Expression 17]

[0130]
From (Expression 15) and (Expression 19), the condition for preventing the light emitted from α from entering the opening 15 is (Expression 20).
[0131]
[Formula 18]

[0132]
Further, when the distance from α to the optical axis is rα, and the distance from the tip of the probe 1 to the center of the refractive lens 13 is Lα, as is well known in geometric optics, rα, Lα, rαF, and LαF are geometrical relationships. (Equation 8) is satisfied. Therefore, (Equation 9) described above is satisfied.
[0133]
By substituting (Equation 9) into (Equation 20), the condition for preventing the light emitted from α from entering the aperture 15 is (Equation 21).
[0134]
[Equation 19]

[0135]
Further, the above-described (Formula 11) is established from the Gauss formula. Therefore, the above (Formula 12) is established.
[0136]
By substituting (Equation 12) into (Equation 21), the condition for not receiving the light emitted from α by the infrared light receiving element 3 is (Equation 22).
[0137]
[Expression 20]

[0138]
As described above, it is necessary to design the optical system so that the condition of (Expression 20), (Expression 21), or (Expression 22) is satisfied so that the light emitted from α does not enter the opening 15. is there. By setting the aperture 15 to be shifted from the focal point of the refractive lens 13 by L3 given by (Equation 20), (Equation 21), and (Equation 22), infrared rays emitted from the probe 1 are transmitted from the aperture 15 to the housing. The infrared light receiving element is not incident on the body 14 and is not received by the infrared light receiving element 3 but only the infrared light emitted from the eardrum and / or its vicinity and passing through the opening of the probe 1 is incident from the opening 15. 3 can receive light. Therefore, a waveguide that blocks infrared rays from the probe 1 is not necessary. In addition, since there is no waveguide that receives heat from the probe 1, it is not necessary to use a material having high thermal conductivity for the refractive lens 13.
[0139]
In Examples 1 to 4 described above, the refractive lens 13 is made of a synthetic resin that transmits infrared rays having a wavelength of about 10 μm, such as polyethylene. The thermal properties of polyethylene are as follows: thermal conductivity λ is 0.34 J / msK, heat capacity is 2.12 × 10 ⁶ J / kgK. For reference, the physical properties of metal, for example, copper, are listed, the thermal conductivity λ is 398 J / msK, and the heat capacity is 3.43 × 10 6. ⁶ J / kgK, indicating that the synthetic resin has a low thermal conductivity and a small heat capacity.
[0140]
At this time, when the radiation thermometer that has been left in the low temperature room is brought into the high temperature room, the light receiving unit 9 including the low temperature refractive lens 13 transiently generates a state where the surrounding air is cooled to be below the dew point. To do.
[0141]
However, since the refractive lens 13 has a small heat capacity, the surface temperature tends to rise, and since the thermal conductivity is small, the surface heat does not diffuse in the thickness direction. Therefore, even if the surface of the refractive lens 13 is below the dew point, the time is short and condensation is not likely to occur. Therefore, even if the ambient temperature of the radiation thermometer changes, the temperature can be accurately detected without the influence of condensation.
[0142]
The example in which the refractive lens is used as the condensing element of the light receiving unit has been described above, but the probe 1 is emitted from the eardrum and / or the vicinity thereof by arranging the infrared light receiving element in the same manner even when the transmission type diffractive lens is used. Only the infrared light that has passed through the opening can enter the housing 14 through the opening 15 and be received by the infrared light receiving element 3, and the lens can be easily molded.
[0143]
(Example 5)
Next, Embodiment 5 of the present invention will be described with reference to FIG. FIG. 8 is a configuration diagram showing a light receiving unit and a probe of a radiation thermometer in Example 5 of the present invention. Here, the condensing element 13 uses a condensing mirror unlike the previous embodiment. In FIG. 8, 1 is a probe, and 3 is an infrared light receiving element, which is built in a case 14 made of a highly reflective metal, and the case 14 is provided with an opening 15 through which infrared rays are incident. Reference numeral 16 denotes a light shield. α, α ′ are virtual tip points where a straight line contacting the inner wall of the probe 1 on the same side as the edge and the optical axis from the edge of the collecting mirror 13 intersects with the tip surface of the probe 1, F is the focal point of the collecting mirror 13, Fα and Fα ′ are image points of α and α ′ by the condenser mirror 13, respectively, and K1α is light reflected from the edge of the condenser mirror 13 on the same side with respect to the optical axis and traveling to Fα (marginal ray). K2α is an optical path of light that travels parallel to the optical axis from α and passes through the focal point F and reaches Fα, and K3α is an optical path of light that reflects from α at the center of the condenser mirror 13 and reaches Fα, K4α is the optical path of light (marginal ray) reflected from the edge of the condenser mirror 13 on the opposite side across the optical axis from α and reaches Kα, and K1α ′ is the condensing on the same side from α ′ to the optical axis. An optical path of light (marginal ray) reflected from the edge of the mirror 13 and traveling to Fα ′, K2α ′ is defined as α ′ to the optical axis. The optical path of the light that goes to the line and passes through the focal point F and reaches Fα ′, K3α ′ is the optical path of the light that is reflected from α ′ at the center of the condenser mirror 13 and reaches Fα ′, and K4α ′ is from α ′. An optical path FX of light (marginal light beam) reflected by the edge of the condenser mirror 13 on the opposite side across the optical axis and reaching Fα ′, FX is an intersection of the optical path K1α and the optical axis.
[0144]
An optical system is designed such that only infrared rays that pass through the opening of the probe 1 enter the opening 15 of the housing 14.
[0145]
The housing 14 is provided inside the light shielding body 16 so that the housing 14 does not receive infrared rays that are not reflected by the condenser mirror 13. The following design is performed after receiving only the infrared ray reflected by the collector mirror.
[0146]
In order to receive only infrared light emitted from the eardrum and / or its vicinity and passing through the opening of the probe 1, it is only necessary not to receive infrared light emitted from the probe 1. Therefore, a point located at the boundary between the region where light is desired to be received and the region where light is not desired is virtually assumed, and from this point, reflection is performed at the edge of the condenser mirror 13 on the same side as the point located at this virtual boundary with respect to the optical axis. What is necessary is just to install the probe 1 so that it may be located far from an optical axis rather than the optical path of the light (marginal light beam) to perform. Therefore, the points located at the virtual boundary are defined as points α and α ′ at which the straight line that contacts the inner wall of the probe 1 on the same side as the edge and the optical axis from the edge of the collector mirror 13 intersects the tip surface of the probe 1. , The opening 15 is placed inside the triangle formed by Fα, Fα ′ and FX. As a result, the probe 1 is positioned farther from the optical axis than the optical paths K1α and K1α ′ between α and the condenser mirror 13, so that an optical system that does not receive light from the probe 1 is obtained.
[0147]
Details of the above will be described below. The light emitted from α reaches the image point Fα of α through the optical paths K1α, K2α, K3α, K4α and the like. As is well known in geometrical optics, the image point Fα of α is formed on the opposite side of α across the optical axis. As shown in FIG. 8, the light passing through the optical path K2α is reflected by the condenser mirror 13, crosses the optical axis at F, and then reaches Fα while leaving the optical axis. Similarly, the light passing through the optical path K1α is reflected by the condensing mirror 13, crosses the optical axis, and then reaches Fα while leaving the optical axis. The light passing through the optical path K3α crosses the optical axis at the condensing mirror 13 and then reaches Fα while leaving the optical axis. The light passing through the optical path K4α crosses the optical axis and is reflected by the condensing mirror 13, and after being reflected by the condensing mirror 13, it reaches Fα without crossing the optical axis. In this way, there is a region where light emitted from α does not pass at a position farther from the collecting mirror 13 than the point FX where the optical path K1α and the optical axis intersect, and closer to the collecting mirror 13 than Fα. . Similarly, with respect to α ′, light emitted from α ′ at a position farther from the collecting mirror 13 than the point where the optical path K1α ′ and the optical axis intersect, and closer to the collecting mirror 13 than Fα ′. There is a region that does not pass through. By installing the opening 15 from the inside of the triangle formed by Fα, Fα ′, and FX, a light receiving unit that does not receive light emitted from α and α ′ can be obtained.
[0148]
Light from a portion farther from the optical axis than the optical path K1α between α and the condenser mirror 13 is replaced with light from a point whose distance from the optical axis is greater than α in the same plane as α. As is well known in geometrical optics, the image point of the condensing mirror 13 at this point is farther from the optical axis than Fα. Therefore, if light from α is not received, light from a point farther from the optical axis than α is not received, and therefore light from the probe 1 is not received. Similarly, light from a portion farther from the optical axis than the optical path K1α ′ between α ′ and the condenser mirror 13 is replaced with light from a point whose distance from the optical axis is greater than α ′ in the same plane as α ′. It is done. As is well known in geometrical optics, the image point of the condensing mirror 13 at this point is farther from the optical axis than Fα ′. Therefore, if light from α ′ is not received, light from a point farther from the optical axis than α ′ is not received, and therefore light from the probe 1 is not received.
[0149]
In this way, by setting the opening 15 inside the triangle formed by Fα, Fα ′, and FX so that infrared rays emitted from α, α ′ do not enter the opening 15, automatically. The infrared light emitted from the probe 1 is not incident on the housing 14 from the opening 15 and is not received by the infrared light receiving element 3.
[0150]
Hereinafter, the position of the opening 15 that does not receive light from α is obtained.
[0151]
The opening 15 is closer to the condenser mirror 13 than Fα. At this time, (Expression 1) is satisfied, and therefore (Expression 2) is satisfied. Here, LαF is the distance from the center of the condenser mirror 13 to the α image point Fα, f is the distance from the center of the condenser mirror 13 to the focal point F, and L3 is the distance from the focal point F to the opening 15.
[0152]
As shown in FIG. 8, since the light receiving surface is between the points FX and Fα where the optical path K1α and the optical axis intersect, the light path closest to the opening 15 is K1α among the light paths from α to Fα. is there. Therefore, in order that the light from α does not enter the opening portion 15, it is necessary to satisfy (Equation 3). Here, rαS1 is the distance from the intersection FαS1 between the optical path K1α and the light receiving surface of the opening 15 to the optical axis, and rS is the radius of the opening 15. When the radius of the condensing mirror 13 is r3 and the distance from the optical axis to the image point Fα is rαF, as is well known in geometric optics, r3, rαF, rαS1, L3, and f satisfy (Equation 4) as a geometric relationship. Therefore, (Equation 5) is satisfied. Also, (Expression 6) is obtained by substituting (Expression 5) into (Expression 3). From (Expression 2) and (Expression 6), the condition for preventing the light emitted from α from entering the opening 15 is (Expression 7).
[0153]
Further, when the distance from α to the optical axis is rα, and the distance from the tip of the probe 1 to the center of the condenser mirror 13 is Lα, as is well known in geometric optics, rα, Lα, rαF, and LαF are geometric relationships. (Equation 8) is satisfied, and therefore (Equation 9) is satisfied. By substituting (Equation 9) into (Equation 7), the condition for preventing the light emitted from α from entering the aperture 15 is (Equation 10). Further, (Equation 11) is established from Gauss's formula, and therefore (Equation 12) is established. By substituting (Equation 12) into (Equation 10), the condition for preventing the light emitted from α from entering the aperture 15 is (Equation 13).
[0154]
As described above, the optical system is designed so as to satisfy (Equation 7), (Equation 10), or (Equation 13) so that light emitted from α at the tip of the probe 1 does not enter the opening 15. There is a need. By setting the aperture 15 to be shifted from the focal point of the collector mirror 10 by L3 given by (Equation 7), (Equation 10), and (Equation 13), infrared rays radiated from the probe 1 enter the aperture 15. Only the infrared rays emitted from the eardrum and / or the vicinity thereof and having passed through the opening of the probe 1 can be incident on the casing 14 from the opening 15 and received by the infrared light receiving element 3 without being incident.
[0155]
(Example 6)
Next, a sixth embodiment of the present invention will be described with reference to FIG. FIG. 9 is a configuration diagram showing a light receiving unit and a probe of a radiation thermometer in Example 6 of the present invention. In FIG. 9, 1 is a probe, 13 is a condensing mirror, 3 is an infrared light receiving element, and is built in a housing 14 made of a highly reflective metal, and an opening 15 through which infrared light enters the housing 14. Is provided. Reference numeral 16 denotes a light shield. α, α ′ are virtual tip points where a straight line contacting the inner wall of the probe 1 on the same side as the edge and the optical axis from the edge of the collecting mirror 13 intersects with the tip surface of the probe 1, F is the focal point of the collecting mirror 13, Fα and Fα ′ are image points of α and α ′ by the condenser mirror 13, respectively, and K1α is light reflected from the edge of the condenser mirror 13 on the same side with respect to the optical axis and traveling to Fα (marginal ray). K2α is an optical path of light that travels parallel to the optical axis from α and passes through the focal point F and reaches Fα, and K3α is an optical path of light that reflects from α at the center of the condenser mirror 13 and reaches Fα, K4α is the optical path of light (marginal ray) reflected from the edge of the condenser mirror 13 on the opposite side across the optical axis from α and reaches Kα, and K1α ′ is the condensing on the same side from α ′ to the optical axis. The optical path of light (marginal ray) that passes through the edge of the mirror 13 and travels to Fα ′, K2α ′ is defined as α ′ to the optical axis. The optical path of the light that goes to the line and passes through the focal point F and reaches Fα ′, K3α ′ is the optical path of the light that is reflected from α ′ at the center of the condenser mirror 13 and reaches Fα ′, and K4α ′ is from α ′ An optical path FX of light (marginal light beam) reflected by the edge of the condenser mirror 13 on the opposite side across the optical axis and reaching Fα ′, FX is an intersection of the optical path K1α and the optical axis.
[0156]
An optical system is designed such that only infrared rays that pass through the aperture of the probe 1 are incident on the aperture 15.
[0157]
The housing 14 is provided inside the light shielding body 16 so that only infrared rays reflected by the condensing mirror 13 enter the opening 15. The following design is performed after the configuration in which only the infrared ray reflected by the condenser mirror 13 is incident.
[0158]
In order to receive only infrared light emitted from the eardrum and / or its vicinity and passing through the opening of the probe 1, it is only necessary not to receive infrared light emitted from the probe 1. Therefore, a point located at the boundary between the region where light is desired to be received and the region where light is not desired is hypothesized, and light reflected from the condensing mirror 13 on the same side as the point located at this virtual boundary with respect to the optical axis. What is necessary is just to install the probe 1 so that it may be located far from an optical axis rather than the optical path of (marginal light beam). Therefore, the points located at the virtual boundary are defined as points α and α ′ at which the straight line that contacts the inner wall of the probe 1 on the same side as the edge and the optical axis from the edge of the collector mirror 13 intersects the tip surface of the probe 1. , The opening 15 is installed in a region sandwiched between the optical path K4α farther from the collector mirror 13 than Fα and the optical path K4α ′ farther from the collector mirror 13 than Fα ′. As a result, the probe 1 is positioned farther from the optical axis than the optical paths K1α and K1α ′ between α and the condenser mirror 13, so that an optical system that does not receive light from the probe 1 is obtained.
[0159]
Details of the above will be described below.
[0160]
The light emitted from α reaches the image point Fα of α through the optical paths K1α, K2α, K3α, K4α and the like. As is well known in geometrical optics, the image point Fα of α is formed on the opposite side of α across the optical axis. As shown in FIG. 9, the light passing through the optical path K2α is reflected by the condensing mirror 13, crosses the optical axis at F, reaches Fα, and moves away from the optical axis. Similarly, light passing through the optical path K1α is reflected by the condenser mirror 13, crosses the optical axis, reaches Fα, and moves away from the optical axis. The light passing through the optical path K3α crosses the optical axis at the condensing mirror 13 to reach Fα and away from the optical axis. The light passing through the optical path K4α crosses the optical axis and is reflected by the collecting mirror 13, and after being reflected by the collecting mirror 13, it reaches Fα without crossing the optical axis and then approaches the optical axis. Go away. In this way, there is a region where light emitted from α does not pass at a position farther from the condenser mirror 13 than the image point Fα of α. Similarly, for α ′, there is a region through which light emitted from α does not pass at a position farther from the condenser mirror 13 than the image point Fα of α. By placing the infrared light receiving element 3 in a region sandwiched between the optical path K4α at a portion farther from the condenser mirror 13 than Fα and the optical path K4α ′ at a portion farther from the condenser mirror 13 than Fα ′, α , Α ′, a light receiving portion that does not receive the infrared rays emitted is obtained. Light from a portion farther from the optical axis than the optical path K1α between α and the condenser mirror 13 is replaced with light from a point whose distance from the optical axis is greater than α in the same plane as α. As is well known in geometrical optics, the image point of the condensing mirror 13 at this point is farther from the optical axis than Fα. Therefore, if light from α is not received, light from a point farther from the optical axis than α is not received, and therefore light from the probe 1 is not received. Similarly, light from a portion farther from the optical axis than the optical path K1α ′ between α ′ and the condenser mirror 13 is replaced with light from a point whose distance from the optical axis is greater than α ′ in the same plane as α ′. It is done. As is well known in geometrical optics, the image point of the condensing mirror 13 at this point is farther from the optical axis than Fα ′. Therefore, if light from α ′ is not received, light from a point farther from the optical axis than α ′ is not received, and therefore light from the probe 1 is not received.
[0161]
Thus, by installing the opening 15 in the region sandwiched between the optical path K4α in the portion farther from the collector mirror 13 than Fα and the optical path K4α ′ in the portion farther from the collector mirror 13 than Fα ′, α, If infrared rays radiated from α ′ are not incident, infrared rays radiated from the probe 1 are not automatically incident on the casing 14 from the opening 15 and are not received by the infrared light receiving element 3.
[0162]
Hereinafter, the position of the opening 15 that does not receive light from α is obtained.
[0163]
The opening 15 is farther from the condenser mirror 13 than Fα. At this time, (Expression 14) is satisfied, and therefore (Expression 15) is satisfied. Here, LαF is the distance from the center of the condenser mirror 13 to the α image point Fα, f is the distance from the center of the condenser mirror 13 to the focal point F, and L3 is the distance from the focal point F to the opening 15.
[0164]
As shown in FIG. 9, since the light receiving surface is farther from the collecting mirror 13 than Fα, the light receiving surface closest to the infrared light receiving element 3 among the light paths from α to Fα is K4α. Therefore, in order to prevent the infrared light receiving element 3 from receiving light from α, it is necessary to satisfy (Equation 16). Here, rαS4 is the distance from the intersection FαS4 between the optical path K4α and the light receiving surface of the infrared light receiving element 3 to the optical axis, and rS is the radius of the opening 15. Assuming that the radius of the condensing mirror 13 is r3 and the distance from the optical axis to the image point Fα is rαF, r3, rαF, LαF, rαS4, L3, and f are geometric relationships as is well known in geometric optics (Equation 17). Therefore, (Equation 18) is satisfied. (Equation 19) is obtained by substituting (Equation 18) into (Equation 16). From (Expression 15) and (Expression 19), the condition for preventing the light emitted from α from entering the opening 15 is (Expression 20).
[0165]
Further, when the distance from α to the optical axis is rα, and the distance from the tip of the probe 1 to the center of the condenser mirror 13 is Lα, as is well known in geometric optics, rα, Lα, rαF, and LαF are geometric relationships. (Equation 8) is satisfied, and therefore (Equation 9) is satisfied. By substituting (Equation 9) into (Equation 20), the condition for preventing the light emitted from α from entering the aperture 15 is (Equation 21). Since (Equation 11) is established from the Gaussian formula, (Equation 12) is established. By substituting (Equation 12) into (Equation 21), the condition for preventing the light emitted from α from entering the aperture 15 is (Equation 22).
[0166]
As described above, it is necessary to design the optical system so that the condition of (Expression 20), (Expression 21), or (Expression 22) is satisfied so that the light emitted from α does not enter the opening 15. is there. By setting the aperture 15 to be shifted from the focal point of the condenser mirror 13 by L3 given by (Equation 20), (Equation 21), and (Equation 22), infrared rays radiated from the probe 1 enter the aperture 15. Only the infrared rays emitted from the eardrum and / or the vicinity thereof and having passed through the opening of the probe 1 can be incident on the opening 15 without being incident.
[0167]
(Example 7)
Next, Embodiment 7 of the present invention will be described with reference to FIG. FIG. 10 shows an example in which a condensing mirror is used as the condensing element, and the first optical axis incident on the condensing mirror and the second optical axis reflected from the condensing mirror are bent. Reference numeral 13 denotes a concave mirror as a condensing element, and its focal point is at F. By cutting out only a part of A to A ′ indicated by a thick line and using it as a condensing mirror, the optical axis passing through the center can be bent and used as indicated by a one-dot chain line. Here, the infrared light receiving element 3 is provided inside the housing 14 having the opening 15 and may be arranged behind the focal point F of the condensing mirror 13, specifically in the range shown in the above-described embodiment. .
[0168]
Considering the ease of use of the radiation thermometer, it is preferable to return to FIG. 1 and bend the probe 1 and the main body 5 about 115 degrees. This is because when the body 5 is held by hand and the probe 1 is inserted into the ear canal, the angle at which the body temperature can be measured at a natural hand position is about 115 degrees. Therefore, if the optical axis is bent by about 115 degrees in FIG. 10, the light receiving part is easily housed in the main body. Moreover, by measuring the body temperature at a natural hand position, the direction in which the probe is inserted into the ear canal is easily stabilized, and the measurement accuracy of the body temperature can be improved.
[0169]
Unlike the refractive lenses described in Examples 1 to 4, the material of the condenser mirror 13 in Examples 5 to 7 does not need to transmit infrared rays. For example, here, polypropylene and polycarbonate are used as the material of the condensing mirror 13, and the surface thereof is subjected to metal deposition or plating. As for the physical properties of polypropylene, the thermal conductivity λ is 0.12 J / msK and the heat capacity is 1.76 × 10. ⁶ J / kgK. The physical properties of polycarbonate are as follows: thermal conductivity λ is 0.19 J / msK, and heat capacity is 1.51 × 10. ⁶ J / kgK, both of which are sufficiently small like the polyethylene described in the example of a refractive lens.
[0170]
With this configuration, infrared light emitted from the probe 1 can be incident on the eardrum and / or the vicinity thereof without entering the housing 14 from the opening 15 and can be received by the infrared light receiving element 3. Therefore, the condensing element 13 is hardly affected by the heat transmitted from the object to be measured, and the optical system does not require high thermal conductivity. Since the light condensing element has a small heat capacity and thermal conductivity, the temperature can be accurately detected without the influence of condensation even when the temperature changes, as in the example of the refractive lens.
[0171]
However, the material used for the collector mirror is not limited to polypropylene, polycarbonate, and polyethylene.
[0172]
As described above, the example in which the condensing mirror is used as the condensing element of the light receiving unit has been described. In addition, even when a reflection type diffractive lens is used, by arranging the opening 15 in the same manner, only infrared rays emitted from the eardrum and / or the vicinity thereof and passing through the opening of the probe 1 are allowed to enter the housing 14 from the opening 15. In addition to being able to receive light by the infrared light receiving element 3, there is an effect that the mirror can be easily formed.
[0173]
In each of the above-described embodiments, infrared light from the inner surface of the probe 1 that is transmitted or reflected by the condensing element 13 and does not enter the opening 15 is incident on the inner surface of the light shielding body 16. However, since the inner surface of the light shielding body 16 is a reflection suppressing means, the incident infrared ray is not reflected and does not enter the opening 15. Accordingly, it is possible to reliably prevent infrared radiation from the probe 1 that causes measurement error from entering the housing 14 through the opening 15 and receiving the infrared light receiving element 3, and to accurately detect the temperature.
[0174]
For the light shield 16, for example, a synthetic resin such as PC, PPS, PBT, PP, or the like is used. It is generally known that the emissivity of these synthetic resins is as high as about 0.9. In addition, infrared light incident on an object is divided into a reflection component, an absorption component, and a transmission component. However, when there is no transmission, the sum of the reflectance and the absorption rate is 1. Here, from Kirchhoff's law, the emissivity and the absorptance are equal, and as a result, it can be said that the synthetic resin having a high emissivity has a low reflectance. Therefore, by forming the light shielding body 16 using these synthetic resins, the light shielding body 16 itself becomes a reflection suppressing means, and unnecessary infrared rays traveling to positions other than the infrared light receiving element 3 are reflected by the light shielding body 16. Thus, it does not enter the infrared light receiving element 3. Accordingly, the function of limiting the light receiving region and preventing unnecessary infrared rays from the probe 1 from entering the infrared light receiving element 3 can be completed.
[0175]
Needless to say, the light shielding body 16 is designed using a synthetic resin that transmits little infrared light and has a thickness sufficient to prevent infrared light from transmitting. Moreover, by using the light shielding body 16 as a synthetic resin, it is difficult for condensation to occur on the light shielding body 16 by the same principle as the light collecting element. If the light shielding body 16 is a metal, the dew condensation generated on the light shielding body 16 moves and adheres to the light condensing element 13. As a result, the light condensing ability may be reduced. There is a possibility that infrared light is scattered by condensation and infrared light emitted from the probe 1 is incident on the infrared light receiving element 3 from the opening 15. However, if the light shield 16 is made of resin, no condensation occurs. There is no such thing.
[0176]
In addition, with the arrangement of the condensing element 13 and the opening 15 described above, it is possible to change the shape of the probe within a range where the infrared rays emitted from the probe do not reach the opening 15. A plurality of probes having different diameters may be provided in addition to the difference in size in the vertical direction. In particular, if the dimension in the length direction is shortened, the diameter can be reduced by the same arrangement of the light condensing element and the infrared light receiving element, and it is possible to provide a probe that can easily cope with infants.
[0177]
In each of the above embodiments, if the output of the infrared light receiving element 3 is a thermopile type having a correlation with the temperature difference from the object, the infrared light receiving element 3 may be used as it is. If the pyroelectric type has a correlation with the change, a chopper for forcibly changing the incident infrared ray may be provided.
[0178]
In each of the embodiments described above, by arranging the opening 15 of the housing 14 at an appropriate position, only infrared light radiated from the eardrum and / or the vicinity thereof can be obtained regardless of the size of the infrared light receiving element 3. I can receive light. That is, even if the range described in the embodiment is only a very small region, and the infrared light receiving element 3 is large, the infrared light receiving element 3 can be used for the eardrum and / or its thin film only by reducing the area of the opening 15. Only infrared light emitted from the vicinity can be received. Here, the casing 14 can be configured simply by using a metal having high reflectance. However, the material may be resin and the inner surface may be vapor-deposited or plated with metal. In addition, the reflectance of the inner surface is increased by making the infrared light incident from the opening 15 incident on the infrared light receiving element 3 while being reflected by the inner surface of the housing, thereby reducing the amount of light received by the infrared light receiving element 3. This is to increase it. When the inner surface is a black body, only the direct light incident from the opening 15 is incident on the infrared light receiving element 3, so that the sensitivity of the infrared light receiving element 3 is sufficiently large and there is no practical problem, the inner surface of the housing 14 It is not necessary to increase the reflectance.
[0179]
【The invention's effect】
As described above, the radiation thermometer of the present invention has the following effects.
[0180]
According to the radiation thermometer according to claim 1 of the present invention, the light receiving unit receives only infrared rays radiated from the eardrum and / or its vicinity and passed through the probe, and the signal processing means calculates the output from the light receiving unit to the temperature. The notification means notifies the temperature of the calculation result. Infrared light collected by the light converging element is incident on the opening of the housing of the light receiving unit. The infrared light incident on the opening is incident on the infrared light receiving device, and is emitted from the eardrum and / or the vicinity thereof. Only the emitted light that has passed through the probe can be spot-detected, and accurate temperature detection can be performed.
[0181]
According to the radiation thermometer according to claim 2 of the present invention, the light receiving unit housed in the main body receives only infrared rays emitted from the eardrum and / or its vicinity and passed through the probe, and the probe has no waveguide inside. Since it is hollow and detachably connected to the main body, there is no deterioration in temperature accuracy due to temperature fluctuations of the waveguide, there is no sanitary problem by replacing the probe, and there is no protruding part if the probe is removed, making it easy to store become.
[0182]
According to the radiation thermometer according to claim 3 of the present invention, since the probe has an open end, a temperature error factor due to variations in infrared transmittance of the cover covering the end is eliminated, and the measurement temperature accuracy can be improved.
[0183]
According to the radiation thermometer according to claim 4 of the present invention, since the probe is stored in the storage portion during non-measurement, the main body has a shape that can be easily stored, and the possibility of losing the removed probe is reduced.
[0184]
According to the radiation thermometer according to claim 5 of the present invention, since a plurality of probes that can be visually discriminated are provided, it is possible to specify a user for each probe and there is no problem of infection due to probe replacement.
[0185]
According to the radiation thermometer according to claim 6 of the present invention, the temperature calculated based on the output from the light receiving unit that receives only infrared rays directly radiated from the eardrum and / or the vicinity thereof is notified by the notification unit having the voice notification unit. Since the notification is made, accurate body temperature can be measured regardless of the time of insertion into the ear.
[0186]
According to the radiation thermometer according to claim 7 of the present invention, since the infrared thermometer that shields infrared rays from the outside of the light condensing element from being incident on the housing, the reflection suppressing means is provided on the housing side of the light shielding body. Infrared rays that have traveled to positions other than the opening of the housing are not reflected and enter the interior of the housing. Therefore, the light receiving area is limited, and infrared rays from other than the eardrum and / or the vicinity thereof are guided to a point other than the opening of the housing, so that accurate body temperature measurement can be performed without being affected by the temperature change of the probe.
[0187]
According to the radiation thermometer according to claim 8 of the present invention, it is generally known that the emissivity of synthetic resin is as high as about 0.9, and infrared reflection is suppressed by using this as a light shielding body. Is done. Further, since the synthetic resin has a low thermal conductivity and a small heat capacity, condensation is unlikely to occur on the surface of the light shielding body. Therefore, the body temperature can be accurately measured without reflection or scattering of infrared rays due to condensation.
[0188]
According to the radiation thermometer according to the ninth aspect of the present invention, a waveguide for shielding infrared rays from the probe is unnecessary, and the optical system including the light collecting element does not require high thermal conductivity. And since the condensing element was comprised from the material with low heat conductivity and a small heat capacity, it is hard to produce dew condensation on the condensing element surface, and an accurate body temperature measurement can be performed.
According to the radiation thermometer according to claim 10 of the present invention, it is generally known that synthetic resin has low thermal conductivity and small heat capacity, and condensation on the surface of the light collecting element can be suppressed by the synthetic resin.
[0189]
According to the radiation thermometer according to claim 11 of the present invention, the infrared rays collected by the light collecting element are incident on the housing, and the opening of the housing is formed on the same side as the virtual tip point. It is farther from the condensing element than the intersection of the optical path that passes through the edge and reaches the image point of the virtual tip point by the condensing element, and closer to the condensing element than the image point of the virtual tip point by the condensing element By installing in the region, the infrared light incident on the light collecting element from the inner wall of the probe can be advanced to a position other than the opening of the housing, and the light receiving region can be limited. Since the infrared light incident from the opening of the housing enters the infrared light receiving element, only the radiated light emitted from the eardrum and / or the vicinity thereof and passing through the probe is spot-like regardless of the size of the infrared light receiving element. It becomes possible to detect.
[0190]
According to the radiation thermometer of claim 12 of the present invention, infrared light collected by the light collecting element is incident on the housing, and the opening of the housing is the edge of the light collecting device on the same side as the virtual tip point. The meridian plane of the condensing element formed by the intersection of the optical axis and the optical axis that passes through and reaches the image point of the virtual tip point by the condensing element and the two image points of the virtual tip point by the condensing element By installing in the inner triangle, infrared rays that enter the light collecting element from the inner wall of the probe can be advanced to a position other than the opening of the housing, and the light receiving area can be limited. Since the infrared light incident from the opening of the housing enters the infrared light receiving element, only the radiated light emitted from the eardrum and / or the vicinity thereof and passing through the probe is spot-like regardless of the size of the infrared light receiving element. It becomes possible to detect.
[0191]
According to the radiation thermometer of the thirteenth aspect of the present invention, the infrared rays collected by the condensing element are incident on the casing, and the opening of the casing has a focal length f of the condensing element and the casing. Using the radius rS of the opening, the distance rα between the virtual tip point and the optical axis, the distance Lα between the virtual tip point and the condensing element, and the radius r3 of the condensing element, L3 given by (Equation 13) By installing it farther from the condensing element than the focal point of the condensing element, infrared rays incident on the condensing element from the probe inner wall can be advanced to a position other than the opening of the housing, and the light receiving area is limited. be able to. Since the infrared light incident on the opening of the housing is incident on the infrared light receiving element, only the radiated light emitted from the eardrum and / or its vicinity and passing through the probe is spot-like regardless of the size of the infrared light receiving element. It becomes possible to detect.
[0192]
According to the radiation thermometer of the fourteenth aspect of the present invention, the infrared rays collected by the light collecting element are incident on the housing, and the opening of the housing is made to extend from the edge of the light collecting device to the optical axis. The straight line drawn so as to contact the inner wall of the probe on the same side as the edge of the light condensing element is located in a region farther from the light condensing element than the image point by the light condensing element at the virtual tip point intersecting the surface of the probe tip. By installing, the infrared ray incident on the light collecting element from the inner wall of the probe can be advanced to a position other than the opening of the housing, and the light receiving area can be limited. Since the infrared light incident on the opening of the housing is incident on the infrared light receiving element, only the radiated light emitted from the eardrum and / or its vicinity and passing through the probe is spot-like regardless of the size of the infrared light receiving element. It becomes possible to detect.
[0193]
According to the radiation thermometer of the fifteenth aspect of the present invention, the infrared rays collected by the condensing element are incident on the casing, and the opening of the casing extends from the edge of the condensing element to the optical axis. The light condensing on the opposite side to the virtual tip point across the optical axis from the virtual tip point where a straight line drawn so as to contact the inner wall of the probe on the same side as the edge of the light collecting element intersects the surface of the tip of the probe Condensed from the inner wall of the probe by being installed in a region sandwiched between two optical paths in the meridian plane of the condensing element that passes through the edge of the element and reaches the image point of the virtual tip point by the condensing element Infrared light incident on the element can be advanced to a position other than the opening of the housing, and the light receiving area can be limited. Since the infrared light incident on the opening of the housing is incident on the infrared light receiving element, only the radiated light emitted from the eardrum and / or its vicinity and passing through the probe is spot-like regardless of the size of the infrared light receiving element. It becomes possible to detect.
[0194]
According to the radiation thermometer of the sixteenth aspect of the present invention, the infrared rays collected by the condensing element are incident on the casing, and the opening of the casing has the focal length f of the condensing element and the casing. Using the radius rS of the opening, the distance rα between the virtual tip point and the optical axis, the distance Lα between the virtual tip point and the light condensing element, and the radius r3 of the light condensing element, they are expressed by (Equation 22). By setting the distance L3 farther from the condensing element than the focal point of the condensing element, infrared light incident on the condensing element from the inner wall of the probe can be advanced to a position other than the opening of the housing. Can be limited. Since the infrared light incident on the opening of the housing is incident on the infrared light receiving element, only the radiated light emitted from the eardrum and / or its vicinity and passing through the probe is spot-like regardless of the size of the infrared light receiving element. It becomes possible to detect.
[0195]
According to the radiation thermometer of the seventeenth aspect of the present invention, the condensed infrared light is incident on the opening of the housing by the refractive lens.
[0196]
According to the radiation thermometer of the eighteenth aspect of the present invention, the condensed infrared light is incident on the opening of the housing by the condensing mirror.
[0197]
According to the radiation thermometer of the nineteenth aspect of the present invention, when the probe and the main body are bent in consideration of the usability as a radiation thermometer that is inserted into the ear canal and measured, the optical system can be bent in accordance with this angle. it can. Therefore, it is easy to use and easy to insert into the ear canal, so that the insertion direction is easy to stabilize and the body temperature can be measured accurately.
[0198]
According to the radiation thermometer of claim 20 of the present invention, by making the inner surface of the casing a highly reflective material, the infrared light receiving element is effectively reflected while reflecting infrared rays incident from the opening of the casing. It can be made incident.
According to the radiation thermometer according to the twenty-first aspect of the present invention, since the metal generally has high reflectance, the housing can be simply configured.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a radiation thermometer according to a first embodiment of the present invention.
FIGS. 2A to 2D are side views of a plurality of probes on which different symbols of the embodiment are printed. FIG.
FIGS. 3A to 3D are side views of a plurality of probes having different dimensions according to the embodiment;
FIG. 4 is a configuration diagram of a light receiving unit and a probe according to the embodiment.
FIG. 5 is a configuration diagram illustrating a light receiving unit and a probe according to a second embodiment of the present invention.
FIG. 6 is a configuration diagram illustrating a light receiving unit and a probe according to a third embodiment of the present invention.
FIG. 7 is a configuration diagram showing a light receiving unit and a probe according to a fourth embodiment of the present invention.
FIG. 8 is a configuration diagram illustrating a light receiving unit and a probe according to a fifth embodiment of the present invention.
FIG. 9 is a configuration diagram illustrating a light receiving unit and a probe according to a sixth embodiment of the present invention.
FIG. 10 is a configuration diagram of a light collecting element according to a seventh embodiment of the present invention.
FIG. 11 is a configuration block diagram of a conventional radiation thermometer.
[Explanation of symbols]
1 Probe
3 Infrared detector
4 Signal processing means
5 Body
7 Storage section
9 Light receiver
10 Notification means
12 Voice notification means
13 Condensing element
14 Case
15 opening
16 Shading body (reflection suppression means)

Claims (21)

A probe that is inserted into the ear canal and transmits infrared rays emitted from the eardrum and / or its vicinity, a light receiving unit that receives the infrared light that has passed through the probe, a signal processing unit that calculates the output of the light receiving unit to temperature, The light receiving portion is an infrared light receiving element, a housing having an infrared light receiving element provided therein and an infrared light incident opening, and at least a probe passed through the light receiving portion. A radiation thermometer comprising a condensing element for condensing infrared light, wherein the light receiving area is limited by installing the opening of the casing away from the focal position of the condensing element. The radiation thermometer according to claim 1, further comprising a main body that houses the light receiving portion, wherein the probe is connected to the main body in a hollow state and is detachable. The radiation thermometer according to claim 2, wherein the probe has an open end. The radiation thermometer according to claim 2, wherein the main body has a storage portion for storing the probe when not measuring. 3. The radiation thermometer according to claim 2, wherein a plurality of probes have a difference that can be visually discriminated. The radiation thermometer according to claim 1, wherein the notification means includes voice notification means for notifying the temperature of the calculation result of the signal processing means by voice. The light receiving unit includes a light shielding body that blocks infrared rays from outside the light collecting element from entering the opening of the housing, and a reflection suppressing unit is provided on the opening of the housing of the light shielding body. Radiation thermometer. The radiation thermometer according to claim 7, wherein a synthetic resin is used as a material of the light shielding body. The radiation thermometer according to claim 1, wherein the condensing element is made of a material having a low thermal conductivity and a small heat capacity. The radiation thermometer according to claim 9, wherein a synthetic resin is used as a material of the light collecting element. A virtual tip where a straight line obtained by drawing the opening of the housing from the edge of the light collecting element so as to contact the inner wall of the probe on the same side as the edge of the light collecting element with respect to the optical axis intersects the surface of the tip of the probe From the point of intersection between the optical axis and the optical path passing through the edge of the condensing element on the same side as the virtual tip point from the point and reaching the image point of the virtual tip point by the condensing element The radiation thermometer according to claim 1, wherein the radiation thermometer is installed in a region far from an optical element and closer to the condensing element than an image point of the virtual tip point by the condensing element. A virtual tip where a straight line obtained by drawing the opening of the housing from the edge of the light collecting element so as to contact the inner wall of the probe on the same side as the edge of the light collecting element with respect to the optical axis intersects the surface of the tip of the probe An intersection of an optical axis and an optical axis that passes through the edge of the condensing element on the same side as the virtual tip point from the point and reaches the image point of the virtual tip point by the condensing element; The radiation thermometer according to claim 11, wherein the radiation thermometer is installed in a triangle in a meridian plane of the light collecting element formed by two image points of the virtual tip point by an optical element. A probe on the same side as the edge of the condensing element with respect to the optical axis from the edge of the condensing element to the focal length f of the condensing element, the radius rS of the opening of the casing, and the optical axis. The distance rα between the virtual tip point and the optical axis where the straight line drawn so as to contact the inner wall of the probe intersects the surface of the probe tip, the distance Lα between the virtual tip point and the light collecting element, Using radius r3,

The radiation thermometer according to claim 12, wherein the radiation thermometer is disposed farther from the light collecting element than the focal point of the light collecting element by L3 given by A virtual tip where a straight line obtained by drawing the opening of the housing from the edge of the light collecting element so as to contact the inner wall of the probe on the same side as the edge of the light collecting element with respect to the optical axis intersects the surface of the tip of the probe The radiation thermometer according to claim 1, wherein the radiation thermometer is installed in a region farther from the light collecting element than an image point formed by the light collecting element. A virtual tip where a straight line obtained by drawing the opening of the housing from the edge of the light collecting element so as to contact the inner wall of the probe on the same side as the edge of the light collecting element with respect to the optical axis intersects the surface of the tip of the probe 2 in the meridian plane of the condensing element that passes through the edge of the condensing element on the opposite side of the virtual tip point from the point and reaches the image point of the virtual tip point by the condensing element The radiation thermometer according to claim 14, wherein the radiation thermometer is installed in a region sandwiched between two optical paths. The opening of the housing has a focal length f of the light collecting element, a radius rS of the opening of the housing, and the edge on the same side as the edge of the light collecting element with respect to the optical axis from the edge of the light collecting element. The distance rα between the virtual tip point and the optical axis where the straight line drawn so as to contact the inner wall of the probe intersects the surface of the tip of the probe, the distance Lα between the virtual tip point and the light condensing element, and the light condensing Using the element radius r3,

The radiation thermometer according to claim 15, wherein the radiation thermometer is disposed farther from the light collecting element than the focal point of the light collecting element by L3 represented by: The radiation thermometer according to claim 1, wherein the condensing element is a refractive lens. The radiation thermometer according to claim 1, wherein the condensing element is a condensing mirror. The condensing mirror is configured to bend a first optical axis incident on the condensing mirror and a second optical axis emitted from the condensing mirror and incident on an opening of a housing. Radiation thermometer. The radiation thermometer according to claim 1, wherein at least an inner surface of the housing is made of a material having high reflectance. The radiation thermometer according to claim 20, wherein the casing is made of metal.

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