JP4098603B2 - Optical sensor - Google Patents

Description

【００５８】
表１及び図４の結果に示すように、比較例では、被検液Ｓの温度の上昇に伴い、急激に測定値が上昇し、その変化量は、約０．６ｐｐｍ／℃であった。
【００５９】
これに対して、本実施例に従い検出部２の温度補償を行った場合、被検液Ｓの温度上昇に対する測定値の変化はごく僅かに抑えられており、その変化量は約０．０２ｐｐｍ／℃程度であった。光学部１が検出部２から分離されていることで、光学部１が被検液Ｓの温度変化に影響されないことが分かる。
【００６０】
［光学部の温度補償］
上述のように、光学部１は、検出部２から分離されており、被検液Ｓに接触することはないので、被検液Ｓの温度変化、被検液Ｓ毎の様々な温度の影響を受けることはない。しかし、上述のように、光学部１、特に、光源１１及び光検出器１２などの光学部品がポリマー薄膜２２よりも温度影響が大きい場合などに、雰囲気温度の変化の影響を受け易い。
【００６１】
そこで、図２に示すように、更に光学部２の内部の温度変化を検出するために、本実施例ではサーミスタとされる温度検出手段（温度センサ）１４を光学部１の内部に設けた。温度検出手段はこれに限定されるものではなく、光学部２の内部の温度情報信号を生成できるものであればよい。温度センサ１４の出力信号は、光学部１の内部の温度を示す信号（温度検出信号）として、光学部１のインターフェイス５５、ケーブル５０内を伸長する信号線５３ｃ、コネクタ５０ａ内の対応する端子、制御部３のインターフェイス３３を介して演算部３１に入力される。
【００６２】
そして、その温度検出結果を用いて、検出部２の温度補償とは独立して、光学部１の温度補償を行う。このように、光学部１と検出部２とを分離し、それぞれ独立して温度検知、温度補償を行うことで、得られる検出結果の再現性、指示値の安定性は更に良好になる。
【００６３】
一例として、本実施例の構成においては、光学部１、特に、光源１１及び光検出器１２に関して、温度Ｔ_Oの雰囲気下の測定で得られる反射強度ＲＯｔと換算基準温度における反射強度ＲＯとの比ｒ_Oと、温度Ｔ_Oとの関係は４次式となる。
【００６４】
ｒ_O＝ＲＯｔ／ＲＯ＝Ａ_OＴ_O ⁴＋Ｂ_OＴ_O ³＋Ｃ_OＴ_O ²＋Ｄ_OＴ_O＋Ｅ_O・・・（２）
Ａ_O、Ｂ_O、Ｃ_O、Ｄ_O、Ｅ_O：定数
従って、予め上記式（２）中の定数を求めておくことによって、温度Ｔ_Oの雰囲気下の測定で得られる反射強度ＲＯｔを、上記（２）より算出した反射強度比で除することで、換算基準温度での値に補償することができる。
【００６５】
上記式（２）中の定数は、光源１１と光検出器１２を含む光学部１の温度依存性、即ち、雰囲気温度を適当に変化させて（少なくとも４種）、検出部２の温度を一定に保つと共に光検出器１２の出力を測定する。そして、出力値と温度との相関式、即ち、上記式（２）中の定数を求める。こうして得た相関式を、テーブル、演算式などの形態で制御部３の記憶部３２に記憶させておき、実際の測定の際には演算部３１がこの記憶部３２に記憶された相関式（２）を用いることによって、温度センサ１４で検出した光源１１及び光検出器１２を含む光学部１の内部の温度から、出力値の温度変化による（基準温度における出力値に対する）変動分を補正する。
【００６６】
そして、上記検出部２と、光学部１とについてそれぞれ独立して求めた補正量を実際の出力値にそれぞれ適用して、光学部１及び検出部２の温度特性による影響を排除した基準温度における出力値を得る。更に、上記同様、この出力値は、有機物濃度（ｐｐｍ）表示に変換されて、表示部３５にて表示される。
【００６７】
本実施例に従う光学部１の温度補償の効果を試験した。
【００６８】
（試験例２）
被検液Ｓとして有機物濃度ゼロの純水を使用して、この水の温度を２５℃恒温にした状態で、周囲の雰囲気温度を１２℃から３５℃に変化させた。この時の出力値を濃度換算し、２５℃での温度を基準として、温度に対する有機物濃度指示値（ｐｐｍ）の変化分を求めた。
【００６９】
試験は、本実施例に従い光学部１の温度補償を行った場合と、図８を参照して説明したように、光源１１及び光検出器１２などの光学部品と検出素子２０とを同一の筐体内に収納し、温度補償を行わなかった場合（比較例）とで行った。結果を表２及び図５に示す。
【００７０】
【表２】

【００７１】
表２及び図５の結果に示すように、比較例では、雰囲気温度の上昇に伴い、急激に測定値が上昇し、その変化量は約２．６ｐｐｍ／℃であった。
【００７２】
これに対して、本実施例に従い光学部１の温度補償を行った場合、雰囲気温度の上昇に対する測定値の変化はごく僅かに抑えられており、その変化量は、約０．０２ｐｐｍ／℃程度であった。
【００７３】
更に、上記光学部１の温度センサ１４に加えて、図２に示すように、光学部１の内部の温度分布が均一となるように、光源１１及び光学部品１２を含む光学部１の光学部品を断熱手段１５で覆い、外部と熱的に遮断した。そして、断熱手段１５で囲包された領域の内部に、温度検出手段１４を設けることで、光学部１としての温度変化をリアルタイムで検出することができる。断熱手段１５としては、発泡スチロール、発泡ウレタンなどを好適に用い得る。本実施例では、発泡ウレタンを用いた。
【００７４】
これにより、例えば、屋外での測定などにおいて光学部１の雰囲気温度が変化した場合であっても、光学部１、特に、光源１１及び光学部品１２などの光学部品はその温度変化から遮断されているため、雰囲気温度の変化が光源１１及び光検出器１２などの光学部品に徐々に伝達されて、指示値がドリフトするようなことは、ほぼ完全に排除することができる。
【００７５】
又、上述では、検出部２から切り離された光学部１は、図１に示すように、ケーブル４０、５０を介して制御部３と検出部２との間に配置されるとした。しかし、本発明はこれに限定されるものではなく、図３に示すように、検出部２から切り離した光学部１を、制御部（計器）３の内部に組み込み、ケーブル４０で検出部２と制御部３内の光学部１とを結合することもできる。図示の例では、制御部３の内部に配置された光学部１は、温度センサ１４及び断熱手段１５を具備する。これにより、通常使用状態においては、光学部１は確実に操作者の雰囲気温度下にあり、被検液Ｓの温度の影響を受けることはない。
【００７６】
尚、上述では、ポリマー薄膜２２の厚みｄの変化による検出素子２０の光学特性の変化によって、反射強度が変化するとして説明したが、本発明は特定の理論に束縛されることを意図しておらず、ポリマー薄膜２２の吸光度、屈折率などのその他の各種パラメータにより反射強度が変化することもある。温度変化によるポリマー薄膜２２の光学特性の変化は、その厚みｄの変化のみならず、吸光度、屈折率などのその他の各種パラメータが温度により変化することによりもたらされたものであっても、本発明は等しく適用可能である。
【００７７】
以上説明した如く、本発明によれば、常に指示値が安定し、再現性の良好な信頼性の高い測定結果を得ることができる。
【００７８】
実施例２
次に、本発明の他の適用例を説明する。
【００７９】
上記各実施例では、ポリマー薄膜２２による光の反射を利用した溶存有機物濃度センサに本発明を適用した場合について説明したが、本発明はこれに限定されるものではない。測定対象と物理的若しくは化学的に相互作用する検出素子が、測定対象に対する感応部材として薄膜を利用する光学センサとしては、干渉増幅反射法センサの他、例えば、表面プラズモン共鳴法センサ（ＳＰＲ）、光導波路型センサ、マッハツェンダー干渉式センサなどの、各種光学的性質を利用して検体中の測定対象の存否及び／又は濃度を測定する光学センサがある。
【００８０】
表面プラズモン共鳴法センサは、金属／液体の界面で表面プラズモンが励起した場合に起こる所謂表面プラズモン共鳴を利用する。表面プラズモン共鳴は、入射角を変化させつつ、検出素子に光を入射させたとき、入射角がある角（共鳴角）の時に反射光の強度が著しく低減する現象である。
【００８１】
表面プラズモン共鳴法センサは、例えば図６に示すように、一般的に、基板、結合手段としてのプリズム２１と、プリズム２１の一面に設けられた金などの金属薄膜２５とを備えてなる検出素子２０が検出部２のセンサボディ２３に具備される。そして、例えば、測定対象（例えば、抗原）と特異的に結合する分子認識物２６（例えば、抗体）などを金属薄膜２５の表面に担持させることにより、検体中の測定対象が付着した金属薄膜２５の表面状態に応じて共鳴角の大きさが変化するため、予め共鳴角と測定対象の濃度との相関を求めておくことで、検体中の測定対象の存否及び／又は濃度を測定することができる。
【００８２】
光導波路型センサとしては、ガラスなどの基板上に光導波路層を形成し、この光導波路の表面に例えば測定対象（例えば、酵素反応基質）と特異的に反応する分子認識物（例えば、酵素）を固定し、基板上に格子結合器などを設けた検出素子を用いるものがある。そして、光導波路層内に光を導入し、例えば、分子認識物と測定対象との反応生成物による吸光量；分子認識物と測定対象との反応生成物の蛍光量；分子認識物と測定対象との反応生成物と、分子認識物と一緒に光導波路層の表面に固定された色素との反応生成物の吸光量；分子認識物と測定対象との反応生成物と、分子認識物と一緒に光導波路層の表面に固定された蛍光物質との反応生成物の蛍光量；などを測定する。この吸光量、蛍光量などと測定対象の濃度との相関を予め求めておくことで、検体中の測定対象の存否及び／又は濃度を測定することができる。
【００８３】
マッハツェンダー干渉計式センサは、位相の揃ったコヒーレント光を、光ファイバやその他の光導波路で２光路に分岐させ、これを再び合流させた時の位相のずれによる干渉パターンの変化を検出して、２光波間の相対的位相変化量を測定する。斯かる原理を利用した測定方法は、分岐した光路の片側に、検体によって光波の位相が変化する検出領域を設置する。例えば、該検出領域において、光ファイバのクラッドを一部取り去り、そこに検出素子として実施例１にて説明したような有機物感応膜をコーティングする。これにより、検体中の有機物との相互作用により感応膜自体の屈折率が変化して光ファイバのコアから漏れ出す光の量が変化し、検出領域を設置した光路と、上流側で分岐されたもう一方の光路を伝搬される光波とで位相差が生じる。この位相のずれを光学部で測定することにより、検体中の有機物の存否及び／又は濃度を検出することができる。
【００８４】
このように、表面プラズモン共鳴法センサ、光導波路型センサ、マッハツェンダー干渉計式センサなどにおいても、検出素子と光学部品とで、その温度の影響の程度及び／又は温度変化に対する応答性に差異があることは、安定な指示値、信頼性ある測定結果を得るために大きな問題となる。又、例えば分子認識物と測定対象との反応性など、検体自体が温度による影響を受けることもあり、その温度変化による影響の程度、応答性は、通常、光学部１とは異なる。従って、このような光学センサにおいても、本発明に従って光学部１と検出素子を設けた検出部２とを分離し、光学部１と検出部２とで独立して温度補償することにより、斯かる問題を解決することができる。
【００８５】
以上の各実施例から明らかなように、本発明は、測定対象と物理的若しくは化学的に相互作用する検出素子の光学特性の変化或いは検体（若しくは測定対象）の光学的特性の変化を検出する検出部と、光源、光検出器などの光学部とを用いて測定対象の存在及び／又は濃度を測定するための光学センサに広く適用し得るものである。
【００８６】
【発明の効果】
以上説明したように、本発明の光学センサは、測定時に検体と接触する検出部と、検出部に光を入力する光源、及び検出部から出力される光を検出する光検出器を備える光学部と、を有し、検出部は検体と相互作用する検出素子を備えており、光源は検出素子に入射する光を発し、光検出器は検出素子から出射される光を検出し、検出部と光学部とは光学部を測定時に検体に接触させずに測定可能なようにそれぞれ別個の筐体に囲包されて互いに分離されていると共に光導波手段を備えるケーブルによって結合されており、且つ、前記検出部及び前記光学部はそれぞれ温度検出手段を有し、検出部の温度検出手段は検出素子の近傍に設けられ、光学部の温度検出手段は光学部の内部に設けられている構成とされるので、雰囲気温度と異なる温度の検体、温度変化する検体或いは温度の異なる一連の検体の測定を行う際などに、常に指示値が安定し、再現性の良好な信頼性の高い測定結果を得ることができる。
【図面の簡単な説明】
【図１】 本発明に係る光学センサの一実施例（溶存有機物濃度センサ）の概略構成図である。
【図２】 本発明に従った光学部の他の構成例を示す概略構成図である。
【図３】 本発明に従った光学センサの光学部の更に他の構成例を示す概略構成図である。
【図４】 検出部の温度補償の効果を示すグラフ図である。
【図５】 光学部の温度補償の効果を示すグラフ図である。
【図６】 本発明を適用し得る光学センサの他の例（表面プラズモン共鳴法センサ（ＳＰＲ））を
説明するための検出部の概略構成図である。
【図７】 溶存有機物濃度センサの測定原理を説明するための模式図である。
【図８】 従来技術に従う光学センサの一例の概略構成図である。
【符号の説明】
１ 光学部
２ 検出部
３ 制御部（計器）
１１ 光源
１２ 光検出器
１４ 温度センサ（光学部温度検出手段）
１５ 断熱手段
２０ 検出素子
２１ プリズム
２２ ポリマー薄膜
２４ 温度センサ（検出部温度検出手段）[0001]
BACKGROUND OF THE INVENTION
The present invention provides a detection unit that detects a change in optical characteristics of a detection element that physically or chemically interacts with a measurement target or a change in optical characteristics of a specimen (or measurement target), a light source, a photodetector, and the like. The present invention relates to an optical sensor for measuring the presence and / or concentration of a measurement object using an optical unit, and more specifically, a sample having a temperature different from the ambient temperature, a sample changing in temperature, or a series of samples having different temperatures. The present invention can be suitably applied to an optical sensor that is used for the above measurement.
[0002]
[Prior art]
Conventionally, presence / absence and / or concentration of a measurement target in a sample by using a change in optical characteristics of a detection element that physically or chemically interacts with the measurement target or a change in optical characteristics of the sample (or measurement target) Various types of optical sensors that directly detect light are proposed.
[0003]
For example, there is an optical sensor that detects an organic substance dissolved in water (for example, see Patent Document 1). This optical sensor measures the amount of light reflection using a polymer thin film as a sensitive member included in the detection element. In other words, using a polymer thin film that interacts with organic substances dissolved in water by reaction, absorption, adsorption, etc. and causing a physical change in film thickness, the physical change of this polymer thin film is measured by interference amplification reflection method, Determine the concentration of organic matter dissolved in water.
[0004]
Further description will be made with reference to FIG. 7. Such an optical sensor includes a detection element 20 and optical components such as a light source 11 and a photodetector 12. The detection element 20 is formed by forming a polymer thin film 22 with a predetermined film thickness on one surface of a prism 21 acting as a substrate and a coupler. Is arranged.
[0005]
The refractive indexes of the prism 21, the polymer thin film 22, and the test solution S are n1, n2, and n3, respectively. When n1> n2> n3, the light is emitted from the light source 11 and is incident on the polymer thin film 22 through the prism 21. The light (incident light) L1 is reflected at the interface between the prism 21 and the polymer thin film 22 and the interface between the polymer thin film 22 and the test solution S, and the light (reflected light) L2 emitted through the prism 21 is detected by light. It is detected by the device 12.
[0006]
At this time, the polymer thin film 22 that comes into contact with the test solution S absorbs organic matter dissolved in water and swells, and the thickness d and the like change to change the light reflection characteristics, and the intensity of the reflected light L2 is increased. Utilizing the change, the concentration of organic matter dissolved in water is measured.
[0007]
In addition, the presence / absence of the measurement target component in the test liquid using the change in the optical characteristics of the detection element that physically or chemically interacts with the measurement target or the change in the optical characteristics of the specimen (or measurement target). Examples of the optical sensor for measuring the density include the following.
[0008]
Similar to the interference amplification reflection method, as an optical sensor using a sensitive film that interacts with a measurement object in a specimen and changes optical characteristics such as reflection characteristics, a surface plasmon resonance sensor (SPR), an optical waveguide sensor, Examples include a Mach-Zehnder interferometer type sensor.
[0009]
Such various optical sensors can detect a measurement target in a specimen directly, typically without a reagent, by detecting a change in optical characteristics, which is simple, quick, and outdoors. It has the advantage of being relatively easy to apply to a portable sensor for measurement, and is extremely useful as a measurement technique.
[0010]
[Patent Document 1]
JP-A-10-104163
[0011]
[Problems to be solved by the invention]
However, for example, when the optical sensor is portable and is used for measurement of a specimen under various environmental conditions, it has been found that there are the following problems.
[0012]
An optical sensor for measuring the concentration of dissolved organic matter in water (hereinafter referred to as “dissolved organic matter concentration sensor”) will be described as an example. The conventional dissolved organic matter concentration sensor includes a detection element including a prism and a polymer thin film, a light source and light. An optical component such as a detector is integrally formed.
[0013]
As shown in FIG. 8, the present inventors arrange optical components such as the light source 11 and the photodetector 12 and the detection element 20 in the same housing (sensor body) 23 to detect a detection unit (sensing). Probe 2), and the light source 11 and the photodetector 12 were connected to the control unit 3 through signal lines 51 and 52 to constitute the dissolved organic matter concentration sensor 200. The detection element 20 formed by forming the polymer thin film 22 on the prism 21 is arranged at the tip of the housing 23 so that the polymer thin film 22 can come into contact with the test solution S. Then, the incident light L 1 emitted from the light source 11 is multiple-reflected in the polymer thin film 22, and the reflected light L 2 is received by the photodetector 12. Using the dissolved organic matter concentration sensor 200, measurement was performed on the test solution S under various environmental conditions.
[0014]
In such a configuration, since the sensor body 23 contacts the test solution S, both the detection element 20 and optical components such as the light source 11 and the photodetector 12 are affected by the temperature of the test solution S. Therefore, when the temperature of the test solution S changes or when the test solution S having a different temperature is measured, the repeatability is poor and reproducible data cannot be obtained, or the indicated value drifts and the stable value is obtained. There was a problem that it could not be obtained.
[0015]
More specifically, as described above, the dissolved organic matter concentration sensor 200 utilizes the fact that the polymer thin film 22 absorbs the dissolved organic matter in the water and swells, and the in-film reflection intensity changes as the film thickness increases. Measure the concentration of organic matter dissolved in water. That is, since the film thickness changes corresponding to the concentration of organic matter dissolved in water, a correlation is obtained between the organic matter concentration and reflected light intensity, and the concentration of dissolved organic matter in water can be measured.
[0016]
As an example, when a polymethacrylic acid copolymer having a film thickness of about 1 μm is used for the polymer thin film 22, the film thickness that fluctuates by absorbing about 100 ppm of an organic substance is about 50 nm. This indicates that a change in film thickness of 0.5 nm corresponds to an organic substance concentration of 1 ppm.
[0017]
However, the polymer thin film 22 swells and contracts in response to changes in the temperature of the test solution S even when there is no organic substance dissolved in water. The polymer thin film 22 may be affected by the temperature of about 0.5 nm / ° C., that is, about 1 ppm / ° C. As a result, when the temperature increases, the indicated value apparently increases, and when the temperature decreases, the indicated value decreases.
[0018]
On the other hand, when an optical component such as the light source 11 or the photodetector 12 has a larger temperature influence than the polymer thin film 22, as an example, when a laser diode is used as the light source 11 and a photodiode is used as the photodetector 12, the temperature influence is It was 3-5 ppm / ° C. When the light source 11 and the light detector 12 are used, the direction affected by the temperature is the same as that of the polymer thin film 22, and as the temperature rises, the indicated value increases apparently, and when the temperature decreases, the indicated value decreases. Become.
[0019]
Importantly, in the actual measurement, when a test solution having a temperature different from room temperature is measured, since the polymer thin film 22 is a thin film, the film instantaneously expands or contracts corresponding to the temperature difference Δt ° C. Thus, a change in the indicated value of Δt × 1 ppm is caused. On the other hand, since the optical components (the light source 11 and the light detector 12) are inside the sensor body 23, it takes time for an external temperature change to be transmitted to the inside, so the temperature characteristics of the polymer thin film 22 cause an instant. After the indicated value fluctuates by Δt × 1 ppm, the indicated value gradually drifts, resulting in an unstable indication value.
[0020]
Patent Document 1 suggests that temperature control or temperature compensation may be required because the refractive index of the polymer thin film and the swelling of the polymer thin film vary with temperature. However, specific means are not shown. In addition, one of the problems recognized by the present inventors, that is, optical parts such as a light source and a photodetector are affected by the liquid temperature of the test liquid, and the indicated value drifts to obtain a stable value. There is no indication of the problem recognition.
[0021]
As described above, the difference in the degree of the influence of temperature and / or the responsiveness to a temperature change between the detection element and the optical component is a big problem for obtaining a stable indication value and a reliable measurement result. It becomes.
[0022]
The problem as described above is not limited to the case where a polymer thin film that swells by absorbing an organic substance is used as a sensitive member of a detection element. The sensitive film used in the surface plasmon resonance sensor, optical waveguide sensor, Mach-Zehnder interferometer sensor, etc. has temperature characteristics, and the degree of temperature characteristics with optical components such as light sources and photodetectors and / or If there is a considerable difference in responsiveness to temperature changes, the same problem as described above occurs.
[0023]
Therefore, the object of the present invention is to provide stable and reliable reproducibility when measuring a sample having a temperature different from the ambient temperature, a sample changing in temperature, or a series of samples having different temperatures. An optical sensor capable of obtaining a high measurement result is provided.
[0024]
[Means for Solving the Problems]
  The above object is achieved by the optical sensor according to the present invention. In summary, the present invention includes a detection unit that contacts a specimen at the time of measurement, a light source that inputs light to the detection unit, and an optical unit that includes a photodetector that detects light output from the detection unit. An optical sensor comprising:
  The detection unit includes a detection element that interacts with a specimen, the light source emits light incident on the detection element, and the photodetector is emitted from the detection element.ReflectionDetect light,
  The detection unit and the optical unit are surrounded by separate casings and separated from each other so that measurement can be performed without bringing the optical unit into contact with the specimen, and are coupled by a cable including optical waveguide means. And each of the detection unit and the optical unit has a temperature detection unit, the temperature detection unit of the detection unit is provided in the vicinity of the detection element, and the temperature detection unit of the optical unit is located inside the optical unit. Provided inAnd
Further, the output of the light detector is based on the detection result of the temperature of the specimen by the temperature detection unit of the detection unit and the detection result of the atmospheric temperature of the optical unit by the temperature detection unit of the optical unit. A control unit that corrects a reflection intensity that is the intensity of the reflected light indicated by the signal, and the control unit includes a relational expression that indicates a relationship between the temperature of the specimen obtained in advance and the reflection intensity, and an atmosphere of the optical unit. By using the relational expression indicating the relationship between temperature and the reflection intensity, the reflection intensity indicated by the output signal of the photodetector is corrected to the reflection intensity at the reference temperature, and the corrected reflection intensity at the reference temperature is obtained. Based on this, the presence / absence and / or concentration of the measurement target in the sample is obtained.This is an optical sensor.
[0025]
  According to an embodiment of the present invention, the optical waveguide means includes an optical fiber that guides light from the light source to the detection element, and an optical fiber that guides light from the detection element to the photodetector. In one embodiment, the optical sensor detects dissolved organic matter in a test solution as a specimen. The detection element may have a polymer thin film that comes into contact with a specimen..
[0026]
  According to a preferred embodiment of the present invention,lightThe optical sensor further includes heat insulating means for enclosing the light source and the light detector. In one embodiment, the temperature detecting means of the optical unit is provided in an area surrounded by the heat insulating means..
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the optical sensor according to the present invention will be described in more detail with reference to the drawings.
[0028]
Example 1
FIG. 1 shows a schematic configuration of an embodiment of an optical sensor according to the present invention. The optical sensor of the present embodiment is a sensor (dissolved organic matter concentration sensor) for measuring the presence and / or concentration of an organic substance dissolved in water, for example, alcohol, toluene, benzene, xylene, hexane, or the like. Further, the optical sensor 100 of this embodiment is configured to be portable.
[0029]
The optical sensor 100 roughly includes an optical unit 1, a detection unit (sensing probe) 2, and a control unit (instrument) 3 as control means.
[0030]
  The optical unit 1 generates a drive signal for the light source 11 according to instructions from the light source 11, the collimator lens 11a, the condenser lens 11b, the light detector 12, and the control unit 3, and the light detector.12The optical unit housing 13 includes a drive circuit 54 that is an electronic circuit that performs amplification processing of the output signal, an interface 55 that serves as a communication unit with the control unit 3, and the like.
[0031]
As the light source 11, a laser light source such as a laser diode (LD), a light emitting diode (LED), or the like can be preferably used. In this example, an LED having a center wavelength of 660 nm was used. In addition, as the photodetector 12, a photoelectric conversion element such as a photodiode or a phototransistor can be preferably used. In this embodiment, a photodiode is used.
[0032]
In addition, a reference light detector used for stabilizing the light amount of the light source 11 as necessary, light emitted from the light source 11, or light incident on the photodetector 12 or the reference light detector. A suitable optical component such as a means for polarizing, splitting, condensing or collimating the light may be further provided.
[0033]
The detection unit 2 includes a detection element 20 in a detection unit housing (sensor body) 23 having a substantially cylindrical shape. The detection element 20 is formed by forming a polymer thin film 22 with a predetermined thickness on one surface of a prism 21 as a substrate and a coupler. The detection element 20 is attached to the sensor body 23 so that the polymer thin film 22 comes into contact with the test solution S when the sensor body 23 is immersed in the test solution S, and the test solution is placed inside the sensor body 23. It is designed not to enter. In addition, a substantially cylindrical light-shielding cover 23a that allows the sample liquid S to flow into the inside so that the detection element 20 is not affected by external light is provided at the tip of the sensor body 23 on the side where the detection element 20 is provided. It is provided to extend.
[0034]
As the polymer thin film 22, vinyl polymers having various side chain groups, polysiloxane and various polycondensation polyesters, polyamides, polyimides, polyurethanes, polyureas, and the like can be used. In this example, a polymethacrylate copolymer was used as the polymer thin film 22 and was formed on one surface of the prism 21 to a thickness of 1.5 μm.
[0035]
The polymer thin film 22 may be formed on a substrate such as glass or plastic, and the prism coupler and the grating coupler may be provided on the side of the substrate opposite to the side where the polymer thin film is provided. The polymer thin film 22 can be formed on the substrate by any known thin film forming method such as a spin coding method or a polymer solution casting method.
[0036]
The detection unit 2 is provided with temperature detection means (temperature sensor) 24. The temperature sensor 24 is a thermistor in this embodiment, and is provided in the vicinity of the polymer thin film 22 in order to detect the temperature of the detection unit 2 having temperature characteristics, in particular, the polymer thin film 22 of the detection element 20. Thereby, the polymer thin film 22 responds instantaneously to the temperature change of the test solution S, and the temperature change can be detected in real time so as to correspond to the change of the indicated value. The temperature detection means is not limited to this, and any means may be used as long as it can generate an environmental temperature information signal of the detection unit 2, particularly the polymer thin film 22 of the detection element 20 in this embodiment.
[0037]
The control unit 3 includes a calculation unit 31 for generating a drive signal for the optical unit 1 and a calculation process for a detection signal, a storage unit 32, an interface 33 as a communication unit with the optical unit 1, measurement start / stop, and various types. An input unit 34 for inputting data and a display unit 35 for displaying measurement results and various set values are provided.
[0038]
As shown in the figure, in the dissolved organic matter concentration sensor 100 of the present embodiment, the optical unit 1 including optical components such as the light source 11 and the photodetector 12 is separated from the sensor body 23 according to the present invention. In the present embodiment, the optical unit 1 is detachable from the control unit 3 via the connector 50a.
[0039]
Next, the operation of the dissolved organic matter concentration sensor 100 will be described.
[0040]
When a measurement start signal is generated from the calculation unit 31 in response to an operator input or the like in the control unit 3, this signal extends through the interface 33 of the control unit 3, the corresponding terminal in the connector 50 a, and the cable 50. Then, the signal is transmitted to the optical unit 1 via the signal line 51 electrically connected to the optical unit 1. This signal is input to the drive circuit 54 via the interface 55 of the optical unit 1, and the light source 11 emits light according to the drive signal generated by the drive circuit 54 according to an instruction from the control unit 3.
[0041]
  Light (incident light) L1 emitted from the light source 11 of the optical unit 1 is guided to an incident light side optical fiber 41 as an optical waveguide means through a collimator lens 11a and a condenser lens 11b. The incident light side optical fiber 41 is extended in the cable 40 which is a coupling portion for optically coupling the optical unit 1 and the detection unit 2 and continues to the detection unit 2. Is incident on the prism 21 in the detector 2. This incident light is further coupled to the polymer thin film 22 by the prism 21 and is reflected multiple times within the polymer thin film 22 as described with reference to FIG. Then, the reflected light L2 is emitted through the prism 21, and is coupled to the reflected light side optical fiber 42 as an optical waveguide means in the detection unit 2. The reflected light side optical fiber 42 extends in the cable 40 and continues to the inside of the optical unit 1, and the reflected light L <b> 2 is a photodetector in the optical unit 1.12Is received.
[0042]
The photodetector 12 outputs an electrical signal proportional to the intensity of the received light. This signal is amplified by the drive circuit 54 and transmitted to the control unit 3 as a signal (detection signal) indicating the intensity of the reflected light L <b> 2 via the interface 55 of the optical unit 1. The detection signal is input to the arithmetic unit 31 via the signal line 52 that is extended in the cable 50 and electrically connected to the control unit 3, the corresponding terminal in the connector 50a, and the interface 33 of the control unit 3. It is used for calculation of measured values.
[0043]
Further, the output signal of the temperature sensor 24 provided in the detection unit 2 is electrically connected to the drive circuit 54 of the optical unit 1 by a signal line 53 a extending in the cable 40, and the temperature of the detection unit 2, In particular, as a signal (temperature detection signal) indicating the environmental temperature of the polymer thin film 22 of the detection element 20, the interface 55 of the optical unit 1, the signal line 53b extending in the cable 50, the corresponding terminal in the connector 50a, the control unit 3 Are input to the arithmetic unit 31 via the interface 33.
[0044]
In this way, by separating the optical unit 1 from the detection unit 2 in contact with the test solution S, it is possible to prevent the optical components such as the light source 11 and the photodetector 12 from being affected by the temperature of the test solution S. it can.
[0045]
That is, as described above, the optical components such as the light source 11 and the photodetector 12 of the optical unit 1 and the polymer thin film 22 of the detection unit 2, particularly the detection element 20, have temperature characteristics. These temperature characteristics have a considerable difference in their responsiveness to temperature changes. Further, as in the present embodiment, the dissolved organic matter concentration sensor 100 is portable. For example, in the case of outdoor measurement, the temperature of the test solution S changes, or tests at various temperatures different from the ambient temperature are performed. It is assumed that the liquid S is measured. Therefore, by separating the optical unit 1 including optical components such as the light source 11 and the photodetector 12 and the detection unit 2 including the detection element 20 and performing temperature compensation as described below, reproducibility and instruction are performed. The stability of the value is much better.
[0046]
In this embodiment, the optical unit 1 is in contact with the test solution S even when the detection unit 2 is immersed in the test solution S and a part of the cable 40 is also immersed in the test solution S. The distance D from the optical unit 1 to the detection unit 2 along the cable 40 is about 1 m so that there is no problem and the workability is good. Of course, this distance D is not limited. It is possible to select the distance D as appropriate so that the optical unit 1 does not come into contact with the test solution S and is not affected by the temperature of the test solution S, and in consideration of other restrictions such as operability. it can.
[0047]
[Temperature compensation of detector]
The temperature compensation of the detection unit 2 is performed using the temperature detection result of the temperature sensor 24 provided in the detection unit 2.
[0048]
In the present embodiment, the calculation unit 31 of the control unit 3 performs temperature compensation of the detection signal of the photodetector 12 from the temperature detection signal of the temperature sensor 24 of the detection unit 2 in accordance with the program and data stored in the storage unit 32. I do.
[0049]
As an example, in the configuration of the present embodiment, the temperature T with respect to the detection unit 2, particularly the polymer thin film 22 of the detection element 20, is described._HRatio r of the reflection intensity RHt obtained by measurement of the test liquid S and the reflection intensity RH at the conversion reference temperature_HAnd temperature T_HIs a quartic equation.
[0050]
r_H= RHt / RH = A_HT_H ^Four+ B_HT_H ^Three+ C_HT_H ²+ D_HT_H+ E_H... (1)
A_H, B_H, C_H, D_H, E_H:constant
Therefore, by obtaining the constant in the above formula (1) in advance, the temperature T_HBy dividing the reflection intensity RHt obtained by the measurement of the test liquid S by the reflection intensity ratio calculated from the above (1), the value at the conversion reference temperature can be compensated.
[0051]
The constant in the above formula (1) is obtained by appropriately changing the temperature dependence of the polymer thin film of the detection unit 2, particularly the detection element 20, that is, the temperature of water having an organic substance concentration of zero (at least four types). And the output value of the photodetector 12 is measured. Then, a correlation equation between the output value and the temperature, that is, a constant in the above equation (1) is obtained. The correlation equation thus obtained is stored in the storage unit 32 of the control unit 3 in the form of a table, an arithmetic expression, etc., and the actual calculation is performed by the calculation unit 31 stored in the storage unit 32. 1) is used to correct the variation due to the temperature change of the output value (relative to the output value at the reference temperature) from the temperature of the test solution S detected by the temperature sensor 24.
[0052]
In this way, the detection signal is corrected by the calculation unit 31, further converted into, for example, organic substance concentration (ppm) display, and displayed on the display unit 35. Of course, it is not limited to the display on the display unit 35, and it may be recorded on a recording medium such as a recording sheet and output via an output device (printer) that the control unit 3 itself has or is communicably connected to. Good. Alternatively, it can be stored in the storage unit 32 or other appropriate storage medium, held, or taken out.
[0053]
In the storage unit 32, the relationship between the output value after temperature compensation, that is, the output value at the reference temperature, and the concentration of dissolved organic matter in the water is determined by table data, The calculation unit 31 calculates the organic substance concentration (ppm) by using this information.
[0054]
The effect of temperature compensation of the detector 2 according to the present embodiment was tested.
[0055]
(Test Example 1)
The ambient temperature was set to a constant temperature of 25 ° C., pure water with an organic substance concentration of zero was used as the test solution S, and the temperature of the water was changed between 20 ° C. and 35 ° C. The output value at this time was converted into a concentration, and the change in the organic substance concentration instruction value (ppm) with respect to the temperature was obtained with the temperature at 25 ° C. as a reference.
[0056]
In the test, when the temperature compensation of the detection unit 2 is performed according to the present embodiment and as described with reference to FIG. 8, the optical component such as the light source 11 and the photodetector 12 and the detection element 20 are placed in the same housing. It was stored in the body and when temperature compensation was not performed (comparative example). In FIG. 8, elements having the same functions and configurations as the dissolved organic matter concentration sensor 100 of the present embodiment are denoted by the same reference numerals. The results are shown in Table 1 and FIG.
[0057]
[Table 1]

[0058]
As shown in the results of Table 1 and FIG. 4, in the comparative example, as the temperature of the test solution S increased, the measured value increased rapidly, and the amount of change was about 0.6 ppm / ° C.
[0059]
On the other hand, when the temperature compensation of the detection unit 2 is performed according to the present embodiment, the change of the measured value with respect to the temperature rise of the test solution S is suppressed very slightly, and the change amount is about 0.02 ppm / It was about ℃. It can be seen that the optical unit 1 is not affected by the temperature change of the test solution S because the optical unit 1 is separated from the detection unit 2.
[0060]
[Optical temperature compensation]
As described above, since the optical unit 1 is separated from the detection unit 2 and does not come into contact with the test solution S, the temperature change of the test solution S and the influence of various temperatures for each test solution S. Not receive. However, as described above, when the optical part 1, in particular, optical components such as the light source 11 and the photodetector 12 have a larger temperature influence than the polymer thin film 22, the optical part 1 is easily affected by changes in the ambient temperature.
[0061]
Therefore, as shown in FIG. 2, in order to detect a temperature change inside the optical unit 2, temperature detecting means (temperature sensor) 14 that is a thermistor in this embodiment is provided inside the optical unit 1. The temperature detecting means is not limited to this, and any means capable of generating a temperature information signal inside the optical unit 2 may be used. The output signal of the temperature sensor 14 is a signal indicating the temperature inside the optical unit 1 (temperature detection signal), an interface 55 of the optical unit 1, a signal line 53c extending in the cable 50, a corresponding terminal in the connector 50a, The data is input to the calculation unit 31 via the interface 33 of the control unit 3.
[0062]
And the temperature compensation of the optical part 1 is performed independently of the temperature compensation of the detection part 2 using the temperature detection result. Thus, by separating the optical unit 1 and the detection unit 2 and independently performing temperature detection and temperature compensation, the reproducibility of the obtained detection result and the stability of the indicated value are further improved.
[0063]
As an example, in the configuration of the present embodiment, the temperature T is related to the optical unit 1, particularly the light source 11 and the photodetector 12._OThe ratio r of the reflection intensity ROt obtained by measurement in the atmosphere of the sample and the reflection intensity RO at the conversion reference temperature_OAnd temperature T_OIs a quartic equation.
[0064]
r_O= ROt / RO = A_OT_O ^Four+ B_OT_O ^Three+ C_OT_O ²+ D_OT_O+ E_O... (2)
A_O, B_O, C_O, D_O, E_O:constant
Accordingly, by obtaining the constant in the above formula (2) in advance, the temperature T_OBy dividing the reflection intensity ROt obtained by the measurement under the above atmosphere by the reflection intensity ratio calculated from (2) above, it is possible to compensate for the value at the conversion reference temperature.
[0065]
The constant in the above formula (2) is the temperature dependence of the optical unit 1 including the light source 11 and the photodetector 12, that is, the ambient temperature is appropriately changed (at least four types), and the temperature of the detection unit 2 is kept constant. And the output of the photodetector 12 is measured. Then, a correlation equation between the output value and the temperature, that is, a constant in the above equation (2) is obtained. The correlation equation thus obtained is stored in the storage unit 32 of the control unit 3 in the form of a table, an arithmetic expression, etc., and the actual calculation is performed by the calculation unit 31 stored in the storage unit 32. 2) is used to correct a variation due to a temperature change of the output value (relative to the output value at the reference temperature) from the temperature inside the optical unit 1 including the light source 11 and the photodetector 12 detected by the temperature sensor 14. .
[0066]
And the correction amount calculated | required independently about the said detection part 2 and the optical part 1 is applied to an actual output value, respectively, in the reference temperature which excluded the influence by the temperature characteristic of the optical part 1 and the detection part 2 Get the output value. Further, as described above, this output value is converted into an organic substance concentration (ppm) display and displayed on the display unit 35.
[0067]
The effect of temperature compensation of the optical unit 1 according to this example was tested.
[0068]
(Test Example 2)
Pure water with an organic substance concentration of zero was used as the test solution S, and the ambient temperature was changed from 12 ° C. to 35 ° C. with the temperature of the water kept constant at 25 ° C. The output value at this time was converted into a concentration, and the change in the organic substance concentration instruction value (ppm) with respect to the temperature was obtained with the temperature at 25 ° C. as a reference.
[0069]
In the test, when the temperature compensation of the optical unit 1 is performed according to the present embodiment and as described with reference to FIG. 8, the optical component such as the light source 11 and the photodetector 12 and the detection element 20 are placed in the same housing. It was stored in the body and when temperature compensation was not performed (comparative example). The results are shown in Table 2 and FIG.
[0070]
[Table 2]

[0071]
As shown in the results of Table 2 and FIG. 5, in the comparative example, as the ambient temperature increased, the measured value increased rapidly, and the amount of change was about 2.6 ppm / ° C.
[0072]
On the other hand, when the temperature compensation of the optical unit 1 is performed according to the present embodiment, the change in the measured value with respect to the increase in the ambient temperature is suppressed to a slight extent, and the change amount is about 0.02 ppm / ° C. Met.
[0073]
Further, in addition to the temperature sensor 14 of the optical unit 1, as shown in FIG. 2, the optical components of the optical unit 1 including the light source 11 and the optical component 12 so that the temperature distribution inside the optical unit 1 is uniform. Was covered with a heat insulating means 15 and thermally insulated from the outside. And the temperature change as the optical part 1 is detectable in real time by providing the temperature detection means 14 inside the area | region enclosed by the heat insulation means 15. FIG. As the heat insulation means 15, styrene foam, urethane foam, or the like can be suitably used. In this example, urethane foam was used.
[0074]
Thereby, for example, even when the ambient temperature of the optical unit 1 changes during outdoor measurement, the optical unit 1, particularly the optical components such as the light source 11 and the optical component 12, are blocked from the temperature change. Therefore, it can be almost completely eliminated that the change in the ambient temperature is gradually transmitted to the optical components such as the light source 11 and the photodetector 12 and the indicated value drifts.
[0075]
In the above description, the optical unit 1 separated from the detection unit 2 is arranged between the control unit 3 and the detection unit 2 via the cables 40 and 50 as shown in FIG. However, the present invention is not limited to this, and as shown in FIG. 3, the optical unit 1 separated from the detection unit 2 is incorporated in the control unit (instrument) 3 and is connected to the detection unit 2 with a cable 40. The optical unit 1 in the control unit 3 can also be coupled. In the illustrated example, the optical unit 1 disposed inside the control unit 3 includes a temperature sensor 14 and a heat insulating means 15. Thereby, in the normal use state, the optical unit 1 is surely under the atmospheric temperature of the operator and is not affected by the temperature of the test solution S.
[0076]
In the above description, it has been described that the reflection intensity changes due to the change in the optical characteristics of the detection element 20 due to the change in the thickness d of the polymer thin film 22, but the present invention is not intended to be bound to a specific theory. First, the reflection intensity may change depending on various other parameters such as absorbance and refractive index of the polymer thin film 22. Even if the change in the optical characteristics of the polymer thin film 22 due to the temperature change is caused not only by the change in the thickness d but also by various other parameters such as absorbance and refractive index, The invention is equally applicable.
[0077]
As described above, according to the present invention, the indicated value is always stable, and a highly reliable measurement result with good reproducibility can be obtained.
[0078]
Example 2
Next, another application example of the present invention will be described.
[0079]
In each of the above embodiments, the case where the present invention is applied to the dissolved organic matter concentration sensor using the reflection of light by the polymer thin film 22 has been described, but the present invention is not limited to this. As an optical sensor that uses a thin film as a sensing member for a measurement object that physically or chemically interacts with the measurement object, in addition to an interference amplification reflection method sensor, for example, a surface plasmon resonance sensor (SPR), There are optical sensors that measure the presence and / or concentration of a measurement target in a specimen using various optical properties, such as an optical waveguide sensor and a Mach-Zehnder interference sensor.
[0080]
A surface plasmon resonance sensor utilizes so-called surface plasmon resonance that occurs when surface plasmons are excited at a metal / liquid interface. Surface plasmon resonance is a phenomenon in which when the incident angle is changed and light is incident on the detection element, the intensity of reflected light is remarkably reduced when the incident angle is a certain angle (resonance angle).
[0081]
For example, as shown in FIG. 6, the surface plasmon resonance sensor generally includes a substrate, a prism 21 as a coupling means, and a metal thin film 25 such as gold provided on one surface of the prism 21. 20 is provided in the sensor body 23 of the detection unit 2. Then, for example, by carrying on the surface of the metal thin film 25 a molecular recognition product 26 (for example, an antibody) that specifically binds to the measurement target (for example, antigen), the metal thin film 25 to which the measurement target in the specimen is attached. Since the magnitude of the resonance angle changes according to the surface state of the sample, the presence / absence and / or concentration of the measurement target in the sample can be measured by obtaining the correlation between the resonance angle and the concentration of the measurement target in advance. it can.
[0082]
As an optical waveguide sensor, an optical waveguide layer is formed on a substrate such as glass, and a molecular recognition substance (for example, an enzyme) that specifically reacts with, for example, a measurement target (for example, an enzyme reaction substrate) on the surface of the optical waveguide. Is used, and a detection element in which a lattice coupler or the like is provided on a substrate is used. Then, light is introduced into the optical waveguide layer. For example, the amount of light absorbed by the reaction product between the molecular recognition product and the measurement target; the fluorescence amount of the reaction product between the molecular recognition product and the measurement target; the molecular recognition product and the measurement target Absorption amount of the reaction product of the reaction product of the molecular recognition product and the dye fixed on the surface of the optical waveguide layer together with the molecular recognition product; together with the reaction product of the molecular recognition product and the measurement target, and the molecular recognition product The amount of fluorescence of the reaction product with the fluorescent substance fixed on the surface of the optical waveguide layer is measured. By obtaining the correlation between the light absorption amount, the fluorescence amount, and the like and the concentration of the measurement target in advance, the presence and / or concentration of the measurement target in the sample can be measured.
[0083]
The Mach-Zehnder interferometer sensor detects the change in the interference pattern due to the phase shift when the coherent light with the same phase is split into two optical paths by an optical fiber or other optical waveguides, and then merged again. The relative phase change between the two light waves is measured. In the measurement method using such a principle, a detection region in which the phase of the light wave changes depending on the specimen is provided on one side of the branched optical path. For example, in the detection region, a part of the clad of the optical fiber is removed, and an organic material sensitive film as described in the first embodiment is coated thereon as a detection element. As a result, the refractive index of the sensitive film itself changes due to the interaction with the organic matter in the specimen, and the amount of light leaking from the core of the optical fiber changes, and the optical path where the detection region is installed and the upstream branch. There is a phase difference between the light wave propagating through the other optical path. By measuring this phase shift with the optical unit, it is possible to detect the presence and / or concentration of the organic substance in the specimen.
[0084]
As described above, even in the surface plasmon resonance sensor, the optical waveguide sensor, the Mach-Zehnder interferometer sensor, etc., there is a difference in the degree of the influence of the temperature and / or the responsiveness to the temperature change between the detection element and the optical component. This is a big problem in order to obtain stable indication values and reliable measurement results. In addition, the specimen itself may be affected by temperature, such as the reactivity between the molecular recognition product and the measurement target, and the degree of influence and the response due to the temperature change are usually different from those of the optical unit 1. Therefore, even in such an optical sensor, according to the present invention, the optical unit 1 and the detection unit 2 provided with the detection element are separated, and the optical unit 1 and the detection unit 2 independently perform temperature compensation. The problem can be solved.
[0085]
As is clear from the above embodiments, the present invention detects a change in the optical characteristics of the detection element that physically or chemically interacts with the measurement target or a change in the optical characteristics of the specimen (or measurement target). The present invention can be widely applied to optical sensors for measuring the presence and / or concentration of a measurement object using a detection unit and an optical unit such as a light source and a photodetector.
[0086]
【The invention's effect】
  As described above, the optical sensor of the present invention includes an optical unit including a detection unit that contacts a specimen at the time of measurement, a light source that inputs light to the detection unit, and a photodetector that detects light output from the detection unit. And havingThe detection unit includes a detection element that interacts with the specimen, the light source emits light incident on the detection element, the photodetector detects light emitted from the detection element,Detection unit and optical unitIs lightTo be able to measure the faculty without touching the specimen during measurementEach enclosed in a separate housingIsolatedAnd coupled by a cable with optical waveguide meansAnd each of the detection unit and the optical unit has a temperature detection means.The temperature detection unit of the detection unit is provided in the vicinity of the detection element, and the temperature detection unit of the optical unit is provided inside the optical unit.Because it is configured, when measuring a sample at a temperature different from the ambient temperature, a sample that changes in temperature, or a series of samples at a different temperature, etc., the indicated value is always stable, and reproducible and highly reliable measurement. The result can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an embodiment (dissolved organic matter concentration sensor) of an optical sensor according to the present invention.
FIG. 2 is a schematic configuration diagram showing another configuration example of an optical unit according to the present invention.
FIG. 3 is a schematic configuration diagram showing still another configuration example of the optical unit of the optical sensor according to the present invention.
FIG. 4 is a graph showing the effect of temperature compensation of a detection unit.
FIG. 5 is a graph showing the effect of temperature compensation of the optical unit.
FIG. 6 shows another example of an optical sensor (surface plasmon resonance sensor (SPR)) to which the present invention can be applied.
It is a schematic block diagram of the detection part for demonstrating.
FIG. 7 is a schematic diagram for explaining the measurement principle of a dissolved organic matter concentration sensor.
FIG. 8 is a schematic configuration diagram of an example of an optical sensor according to the prior art.
[Explanation of symbols]
  1 Optical part
  2 detector
  3 Control unit (instrument)
  11 Light source
  12    Photodetector
  14 Temperature sensor (Optical part temperature detection means)
  15 Insulation means
  20 sensing element
  21 Prism
  22 Polymer thin film
  24 Temperature sensor (detector temperature detection means)

Claims (6)

An optical sensor having a detection unit that comes into contact with a specimen at the time of measurement, a light source that inputs light to the detection unit, and an optical unit that includes a photodetector that detects light output from the detection unit,
The detection unit includes a detection element that interacts with a specimen, the light source emits light incident on the detection element, the photodetector detects reflected light emitted from the detection element,
The detection unit and the optical unit are surrounded by separate casings and separated from each other so that measurement can be performed without bringing the optical unit into contact with the specimen, and are coupled by a cable including optical waveguide means. And each of the detection unit and the optical unit has a temperature detection unit, the temperature detection unit of the detection unit is provided in the vicinity of the detection element, and the temperature detection unit of the optical unit is located inside the optical unit. is provided to,
Further, the output of the light detector is based on the detection result of the temperature of the specimen by the temperature detection unit of the detection unit and the detection result of the atmospheric temperature of the optical unit by the temperature detection unit of the optical unit. A control unit that corrects a reflection intensity that is the intensity of the reflected light indicated by the signal, and the control unit includes a relational expression that indicates a relationship between the temperature of the specimen obtained in advance and the reflection intensity, and an atmosphere of the optical unit. By using the relational expression indicating the relationship between temperature and the reflection intensity, the reflection intensity indicated by the output signal of the photodetector is corrected to the reflection intensity at the reference temperature, and the corrected reflection intensity at the reference temperature is obtained. An optical sensor characterized in that the presence / absence and / or concentration of a measurement target in a sample is obtained .   2. The optical device according to claim 1, wherein the optical waveguide means includes an optical fiber that guides light from the light source to the detection element, and an optical fiber that guides light from the detection element to the photodetector. Sensor.   3. The optical sensor according to claim 1, wherein a dissolved organic substance in a test liquid as a specimen is detected.   The optical sensor according to claim 1, wherein the detection element includes a polymer thin film that comes into contact with a specimen. Furthermore, the optical sensor according to any of claims 1-4, characterized in that it comprises a heat insulating means encloses the light source and the light detector. 6. The optical sensor according to claim 5 , wherein the temperature detection means included in the optical unit is provided inside a region surrounded by the heat insulation means.

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