JP2007205920A - Multiple reflection type cell, and infrared type gas detector - Google Patents
Multiple reflection type cell, and infrared type gas detector Download PDFInfo
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Abstract
Description
本発明は、多重反射型セルおよび当該多重反射型セルを備えた赤外線式ガス検知器に関する。 The present invention relates to a multiple reflection type cell and an infrared gas detector including the multiple reflection type cell.
現在、例えば赤外線が検知対象ガス（特定ガス成分）によって吸収されることによる赤外線量の減衰の程度に応じてガス濃度を検出する、非分散型赤外線吸収法を利用した赤外線式ガス検知器が多数提案されている。
このような赤外線式ガス検知器においては、ガス検知が行われる対象となる、例えば環境雰囲気の空気などの被検ガスが導入されるガスセル内における赤外光の光路長が大きくなるに従って、低濃度域の特定ガス成分に対して高い感度が得られることが知られている。
Currently, for example, there are many infrared gas detectors using non-dispersive infrared absorption methods that detect gas concentration according to the degree of attenuation of the amount of infrared rays due to absorption of infrared rays by the detection target gas (specific gas component), for example. Proposed.
In such an infrared gas detector, as the optical path length of infrared light in a gas cell into which a gas to be detected is introduced, for example, a gas to be detected such as air in an environmental atmosphere, the concentration decreases. It is known that high sensitivity can be obtained for specific gas components in the region.
従来より、ガスセルの容積を大幅に増大させることなしに、限られた空間内で必要とされる十分な大きさの光路長を得るための手段として、いわゆる『ホワイトセル』の動作原理を利用した多重反射型のガスセルが広く利用されている。
このようなガスセルとしては、例えば曲率半径の大きさが互いに等しい３つの凹面反射鏡を用い、一の凹面鏡を中央反射鏡とし、他の２つの反射鏡をその曲率中心の位置が中央反射鏡の反射面上に位置された構成のもの（例えば特許文献１参照）や、一の凹面鏡と一の平面鏡を用い、凹面鏡の曲率中心が平面鏡の反射面上に位置された構成のもの（例えば特許文献２参照）、あるいは、２重管構造の円筒形状のセンサハウジングを具え、外筒壁と内筒壁との間の空間に光源が配置されると共に内筒壁の内側に検出素子が配置されてなり、光源からの放射光を外筒壁の内面および内筒壁の外面によって形成される反射面により多重反射させて内筒壁に形成されたギャップを介して光検出素子に入射させる構成のもの（例えば特許文献３参照）などが知られている。
Conventionally, the so-called “white cell” operating principle has been used as a means to obtain a sufficiently large optical path length required in a limited space without significantly increasing the volume of the gas cell. Multiple reflection type gas cells are widely used.
As such a gas cell, for example, three concave reflecting mirrors having the same radius of curvature are used, one concave mirror is a central reflecting mirror, and the other two reflecting mirrors are located at the center of curvature of the central reflecting mirror. One having a configuration positioned on the reflecting surface (see, for example, Patent Document 1), or one having a concave mirror and one plane mirror, and a configuration in which the center of curvature of the concave mirror is positioned on the reflecting surface of the plane mirror (for example, Patent Document 1) 2) or a cylindrical sensor housing having a double tube structure, a light source is arranged in a space between the outer cylinder wall and the inner cylinder wall, and a detection element is arranged inside the inner cylinder wall. And having a configuration in which the radiated light from the light source is reflected by the reflecting surface formed by the inner surface of the outer cylinder wall and the outer surface of the inner cylinder wall and is incident on the light detection element through the gap formed in the inner cylinder wall. (See, for example, Patent Document 3) It is known.
しかしながら、例えば特許文献１および特許文献２に開示されている凹面鏡を利用した多重反射型セルにおいては、（イ）凹面鏡の設置（組配）に高い精度が要求されて作製が困難である、また、（ロ）必要な大きさの光路長を得るために、反射回数の設定を変更すると、凹面鏡の形状等の大幅な設計変更が必要となる、などの問題がある。
また、特許文献３に開示されている多重反射型セルにおいては、（ハ）得られる光路長の大きさの割には、反射回数が多くなるため、光検出素子からの出力信号が弱くなる、あるいは、（ニ）円形状の反射面を利用して壁面に沿った光路を形成しているため、光路の制御が困難であり、反射面の形成に高い精度が必要とされるため、個体差やロット差が発生しやすく、個々のガスセル毎に調整作業が必要となって不便である、などの問題がある。
However, for example, in the multiple reflection type cell using the concave mirrors disclosed in Patent Document 1 and Patent Document 2, (a) high accuracy is required for the installation (combination) of the concave mirrors. (B) When the setting of the number of reflections is changed in order to obtain a required optical path length, there is a problem that a significant design change such as the shape of the concave mirror is required.
Further, in the multiple reflection type cell disclosed in Patent Document 3, (c) the number of reflections increases for the size of the obtained optical path length, and the output signal from the light detection element becomes weak. Alternatively, (d) Since the optical path along the wall surface is formed using a circular reflecting surface, it is difficult to control the optical path, and high accuracy is required to form the reflecting surface. And lot differences are likely to occur, and adjustment work is required for each gas cell, which is inconvenient.
本発明は、以上のような事情に基づいてなされたものであって、その目的は、必要とされる十分な大きさの光路長を得ることができ、しかも、小型のものとして構成することができる多重反射型セルを提供することにある。
また、本発明の他の目的は、個体差およびロット差を生じさせることなく、容易に作製することのできる多重反射型セルを提供することにある。
本発明の更に他の目的は、上記多重反射型セルを備え、所期のガス検知を確実に行うことのできる小型の赤外線式ガス検知器を提供することにある。
The present invention has been made on the basis of the above circumstances, and the object thereof is to obtain a sufficiently large optical path length as required, and to be configured as a small one. An object of the present invention is to provide a multi-reflection cell that can be used.
Another object of the present invention is to provide a multi-reflection cell that can be easily manufactured without causing individual differences and lot differences.
Still another object of the present invention is to provide a small-sized infrared gas detector that includes the above-described multiple reflection type cell and can reliably perform desired gas detection.
本発明の多重反射型セルは、光源からの放射光を多重反射して光検出器に入射させる多重反射型セルであって、
焦点距離の大きさが互いに異なる２つの放物面反射鏡が焦点の位置が一致する状態で対向して配置されてなることを特徴とする。
The multiple reflection type cell of the present invention is a multiple reflection type cell that multiple-reflects radiated light from a light source and makes it incident on a photodetector,
Two paraboloidal reflectors having different focal lengths are arranged to face each other in a state where the focal points coincide with each other.
本発明の多重反射型セルにおいては、２つの放物面反射鏡が口径が互いに異なる大きさのものであって、
口径が小さい一方の放物面反射鏡の外縁部分が、外匣に設けられた光透過性を有する枠状の窓部材によって支持されて、２つの放物面反射鏡間に測定対象物が導入される測定対象物導入空間が形成されており、
一方の放物面反射鏡および窓部材によって当該測定対象物導入空間と区画された空間部に光源が配置されていると共に、口径が大きい他方の放物面反射鏡の背面に、当該他方の放物面反射鏡に設けられた窓部材を介して光検出器が配置された構成とすることができる。
In the multiple reflection type cell of the present invention, the two parabolic reflectors have different calibers,
The outer edge portion of one paraboloidal reflector having a small diameter is supported by a light-transmitting frame-shaped window member provided on the outer casing, and the measurement object is introduced between the two paraboloidal reflectors. The measurement object introduction space is formed,
A light source is arranged in a space sectioned from the measurement object introduction space by one parabolic reflector and a window member, and the other parabolic reflector has a large aperture on the back surface of the other parabolic reflector. It can be set as the structure by which the photodetector is arrange | positioned through the window member provided in the object surface reflecting mirror.
また、本発明の多重反射型セルにおいては、全体を円筒形状のものとして構成することができる。 Moreover, in the multiple reflection type cell of the present invention, the whole can be configured as a cylindrical one.
本発明の赤外線式ガス検知器は、上記多重反射型セルを備えてなることを特徴とする。 An infrared gas detector according to the present invention includes the above-described multiple reflection type cell.
本発明の多重反射型セルによれば、２つの放物面反射鏡が特定の光学条件を満足する状態で合理的に配置されて多重反射構造が形成されているので、必要とされる十分な大きさの光路長を得ることができる構成のものでありながら小型のものとして構成することができる。
また、所定の多重反射構造を得るために必要とされる構成部材が２つの放物面反射鏡のみであり、当該２つの放物面反射鏡を焦点の位置を一致させた状態で配置すればよいので、光路の制御が容易であると共に複雑な（煩雑な）光学調整が不要であり、個体差やロット差を生じさせることなしに、所期の機能を有するものを容易に作製することができる。
According to the multiple reflection type cell of the present invention, two paraboloidal reflectors are rationally arranged in a state satisfying a specific optical condition to form a multiple reflection structure. Although it is a thing of the structure which can obtain the optical path length of a magnitude | size, it can comprise as a small thing.
In addition, if only two paraboloidal reflectors are necessary to obtain a predetermined multiple reflection structure, the two paraboloidal reflectors can be arranged with their focal points aligned. Because it is good, it is easy to control the optical path, and no complicated (complex) optical adjustment is required, and it is possible to easily produce a product having the intended function without causing individual differences or lot differences. it can.
上記多重反射型セルを備えてなる本発明の赤外線式ガス検知器によれば、基本的に装置全体の小型化を図ることができると共に、所期のガス検知を高い信頼性をもって行うことができ、しかも、ガスセルそれ自体が小型のものであることにより、ガスの置換が速やかに行われて高い応答性を得ることができる。 According to the infrared gas detector of the present invention comprising the above-described multiple reflection type cell, it is possible to basically reduce the size of the entire apparatus and to perform desired gas detection with high reliability. Moreover, since the gas cell itself is small, the gas can be replaced quickly and high responsiveness can be obtained.
以下、本発明について詳細に説明する。
本発明の赤外線式ガス検知器は、赤外線光源からの赤外光を被検ガスが導入されるガスセル内において多重反射させて、赤外線センサにより受光される赤外線量に応じたガス検知信号を出力するガス検知部を備えてなるものである。
The present invention will be described in detail below.
The infrared gas detector of the present invention multi-reflects infrared light from an infrared light source in a gas cell into which a test gas is introduced, and outputs a gas detection signal corresponding to the amount of infrared light received by the infrared sensor. A gas detector is provided.
図１は、本発明の赤外線式ガス検知器におけるガス検知部を構成する多重反射型セルの一例における構成の概略を示す説明用断面図である。
この多重反射型セル（以下、単に「ガスセル」という。）１０は、全体が円筒形状の外匣１１を具えてなり、この外匣１１内には、特定の波長域の光、この実施例においては赤外光に対して高い光透過性を有するリング状の入射側窓部材１５が高さ方向における所定の位置において外匣１１の中心軸Ｃと垂直な方向に伸びるよう設けられており、この入射側窓部材１５によって外匣１１の内部空間が区画されてチャンバ部１２および光源配置部１３が形成されている。
FIG. 1 is an explanatory cross-sectional view showing an outline of a configuration of an example of a multiple reflection type cell constituting a gas detection unit in an infrared gas detector of the present invention.
The multiple reflection type cell (hereinafter, simply referred to as “gas cell”) 10 includes a cylindrical outer casing 11, in which light in a specific wavelength region, in this embodiment, is included. Is provided with a ring-shaped incident side window member 15 having high light transmittance with respect to infrared light so as to extend in a direction perpendicular to the central axis C of the outer casing 11 at a predetermined position in the height direction. The interior space of the outer casing 11 is partitioned by the incident side window member 15 to form the chamber section 12 and the light source arrangement section 13.
チャンバ部１２には、焦点距離の大きさが互いに異なる２つの放物面反射鏡２０，２５が焦点の位置が一致すると共に、放物面反射鏡２０，２５の中心軸が外匣１１の中心軸Ｃと一致した状態で対向配置されている。
各々の放物面反射鏡２０，２５は、内面に、赤外域の光を反射させて、不要な波長域の光を反射鏡の背後に透過させる機能を有する反射膜（図示せず）が形成されており、これにより、例えば放物面状の反射面２１，２６が形成されている。
各々の放物面反射鏡２０，２５は、口径（外縁部分の内径寸法）が互いに異なる大きさのものであり、口径が小さい一方の放物面反射鏡（以下、「出射側反射鏡」ともいう。）２０の外縁部分が入射側窓部材１５によって支持されていると共に、口径が大きい他方の放物面反射鏡（以下、「入射側反射鏡」ともいう。）２５が外匣１１に設けられた適宜の支持部材によって支持されており、これにより、２つの放物面反射鏡２０，２５間に測定対象物としての被検ガスが導入されるガス導入空間Ｓが形成されている。図１において、１６はガス導入部、１７はガス排出部であり、各々、ガス導入空間Ｓに連通している。
In the chamber portion 12, two paraboloidal reflectors 20 and 25 having different focal lengths have the same focal point, and the center axis of the paraboloidal reflectors 20 and 25 is the center of the outer casing 11. They are arranged opposite to each other so as to coincide with the axis C.
Each of the parabolic reflecting mirrors 20 and 25 is formed with a reflecting film (not shown) having a function of reflecting light in the infrared region and transmitting light in an unnecessary wavelength region behind the reflecting mirror on the inner surface. Thus, for example, parabolic reflecting surfaces 21 and 26 are formed.
Each of the parabolic reflectors 20 and 25 has a different diameter (the inner diameter of the outer edge portion), and one of the smaller paraboloid reflectors (hereinafter referred to as “exit-side reflector”). The outer edge portion of 20 is supported by the incident-side window member 15 and the other parabolic reflector (hereinafter also referred to as “incident-side reflector”) 25 having a large aperture is provided on the outer casing 11. Thus, a gas introduction space S is formed between the two paraboloid reflecting mirrors 20 and 25, into which a test gas as a measurement object is introduced. In FIG. 1, 16 is a gas introduction part, 17 is a gas discharge part, and each communicates with the gas introduction space S.
入射側反射鏡２５には、中央位置に光出射用の開口２７が形成されており、この開口２７を塞ぐよう赤外線に対して高い光透過性を有する出射側窓部材２８が設けられている。 入射側反射鏡２５の背面には、出射側窓部材２８と対向した位置において、光検出器である赤外線センサ３０が配置されており、受光部１４が外匣１１内においてチャンバ部１２と一体に構成されている。 The incident-side reflecting mirror 25 is formed with an opening 27 for light emission at a central position, and an emission-side window member 28 having high light transmittance with respect to infrared rays is provided so as to close the opening 27. An infrared sensor 30 as a photodetector is disposed on the back surface of the incident-side reflecting mirror 25 at a position facing the emission-side window member 28, and the light-receiving unit 14 is integrated with the chamber unit 12 in the outer casing 11. It is configured.
光源配置部１３には、例えば凹面反射鏡３５がその反射面が上方を向いた状態で配置されていると共に、この凹面反射鏡３５の焦点の位置に、赤外線光源４０が配置されている。 For example, a concave reflecting mirror 35 is arranged in the light source arrangement unit 13 with its reflecting surface facing upward, and an infrared light source 40 is arranged at the focal point of the concave reflecting mirror 35.
このガスセル１０においては、次のようにして各構成部材の諸元が設定される。すなわち、検知対象ガス（特定ガス成分）の種類と測定濃度範囲とに基づいて所期のガス検知を行うために必要とされる、光路長の大きさおよび反射回数が設定され、これらの設定値に基づいて２つの放物面反射鏡２０，２５における対向する反射面間の離間距離の大きさが設定される。
そして、２つの放物面反射鏡２０，２５の緒元すなわち焦点距離、口径等が選定されると共に、赤外線光源４０からの赤外光の、入射側窓部材１５を介してガス導入空間Ｓに入射される入射位置、および入射側反射鏡２５における開口２７の大きさおよび形成位置が設定される。ここに、入射側反射鏡２５の口径の大きさは、入射側窓部材１５を介してチャンバ部１２内に導入される赤外光および出射側反射鏡２０により反射される反射光Ｉ２の実質的に全部（出射側窓部材２８を介して出射される反射光を除く。）が受光されるよう設定され、出射側反射鏡２０の口径の設定を行うに際しては、入射側反射鏡２５の反射面２６によって反射される反射光Ｉ１のすべてが受光されるよう設定される。
以上において、入射側反射鏡２５および出射側反射鏡２０による反射回数は、赤外線センサ３０によって十分な大きさの出力信号が得られるよう、例えば１５回以下の範囲内で設定されることが好ましい。
また、入射側反射鏡２５と出射側反射鏡２０との焦点距離の差の程度は、所定の多重反射構造が形成されると共にガスセル１０が大型化することが防止されれば、特に制限されるものではない。
In the gas cell 10, the specifications of each component are set as follows. In other words, the size of the optical path length and the number of reflections required for performing the desired gas detection based on the type of detection target gas (specific gas component) and the measured concentration range are set, and these set values Is set to the distance between the opposing reflecting surfaces of the two parabolic reflecting mirrors 20 and 25.
Then, the specifications of the two parabolic reflectors 20 and 25, that is, the focal length, the aperture, and the like are selected, and the infrared light from the infrared light source 40 enters the gas introduction space S through the incident side window member 15. The incident position where the light enters and the size and position of the opening 27 in the incident-side reflecting mirror 25 are set. Here, the size of the aperture of the incident-side reflecting mirror 25 is substantially equal to the infrared light introduced into the chamber portion 12 through the incident-side window member 15 and the reflected light I2 reflected by the emitting-side reflecting mirror 20. When the aperture of the exit-side reflecting mirror 20 is set, the reflecting surface of the entrance-side reflecting mirror 25 is set to receive all the light (excluding the reflected light emitted through the exit-side window member 28). It is set so that all of the reflected light I1 reflected by 26 is received.
In the above, the number of reflections by the incident-side reflecting mirror 25 and the emitting-side reflecting mirror 20 is preferably set within a range of, for example, 15 times or less so that a sufficiently large output signal can be obtained by the infrared sensor 30.
Further, the degree of the difference in focal length between the incident-side reflecting mirror 25 and the emitting-side reflecting mirror 20 is particularly limited if a predetermined multiple reflection structure is formed and the gas cell 10 is prevented from being enlarged. It is not a thing.
上記構成のガスセル１０においては、赤外線光源４０から放射された赤外光が光源配置部１４に配置された凹面反射鏡３５によって反射されて外匣１１の中心軸Ｃ（凹面鏡の中心軸）と平行な光とされて入射側窓部材１５を介してガス導入空間Ｓ内に導入される。そして、ガス導入空間Ｓ内に導入された赤外光は、入射側反射鏡２５の反射面２６により反射され、その反射光Ｉ１（図１において一点鎖線で示す。）が焦点Ｆを通過して出射側反射鏡２０の反射面２１により反射されて、再び、外匣１１の中心軸Ｃと平行な光とされる。
そして、出射側反射鏡２０の反射面２１により反射された反射光Ｉ２（図１において破線で示す。）は、入射側反射鏡２５の反射面２６により反射され、このような反射が繰り返し行われながら、各々の放物面反射鏡２０，２５の反射面２１，２６上に形成される像点の位置が中心軸Ｃに近づいていき、入射側反射鏡２５における出射側窓部材２８を介して出射されて赤外線センサ３０に入射される。この実施例に係るガスセル１０における反射回数は、例えば１２回とされている。
一方、被検ガスがガス導入部１６よりガス導入空間Ｓ内に導入されて、当該被検ガス中に検知対象ガス（特定ガス成分）が含まれる場合には、当該特定ガス成分によって赤外線が吸収されることによって赤外線センサ３０に検出される赤外線光量が低下し、この赤外線光量の減衰の程度に応じた検知対象ガスの濃度が算出される。
In the gas cell 10 having the above configuration, the infrared light emitted from the infrared light source 40 is reflected by the concave reflecting mirror 35 arranged in the light source arrangement unit 14 and parallel to the central axis C of the outer casing 11 (the central axis of the concave mirror). And is introduced into the gas introduction space S through the incident side window member 15. The infrared light introduced into the gas introduction space S is reflected by the reflecting surface 26 of the incident side reflecting mirror 25, and the reflected light I1 (shown by a one-dot chain line in FIG. 1) passes through the focal point F. The light is reflected by the reflecting surface 21 of the exit-side reflecting mirror 20 and again becomes light parallel to the central axis C of the outer casing 11.
Then, the reflected light I2 (indicated by a broken line in FIG. 1) reflected by the reflecting surface 21 of the emitting side reflecting mirror 20 is reflected by the reflecting surface 26 of the incident side reflecting mirror 25, and such reflection is repeated. However, the positions of the image points formed on the reflecting surfaces 21 and 26 of the paraboloid reflecting mirrors 20 and 25 approach the central axis C, and pass through the exit-side window member 28 in the incident-side reflecting mirror 25. It is emitted and incident on the infrared sensor 30. The number of reflections in the gas cell 10 according to this embodiment is, for example, 12 times.
On the other hand, when the test gas is introduced into the gas introduction space S from the gas introduction unit 16 and the detection target gas (specific gas component) is included in the test gas, infrared light is absorbed by the specific gas component. As a result, the amount of infrared light detected by the infrared sensor 30 is reduced, and the concentration of the detection target gas corresponding to the degree of attenuation of the infrared light amount is calculated.
而して、上記構成のガスセル１０によれば、２つの放物面反射鏡２０，２５が特定の光学条件を満足する状態で合理的に配置されて多重反射構造が形成されているので、以下に示す具体的な実施例の結果からも明らかなように、必要とされる十分な大きさの光路長を得ることができる構成のものでありながら小型のものとして構成することができる。 Thus, according to the gas cell 10 having the above configuration, the two parabolic reflectors 20 and 25 are rationally arranged in a state satisfying a specific optical condition to form a multiple reflection structure. As is clear from the results of the specific examples shown in (1), the optical path length of a sufficiently large size can be obtained, but it can be configured as a small one.
〔構成例１〕
出射側反射鏡（２０）として焦点距離が１５ｍｍのもの、入射側反射鏡（２５）として焦点距離が２５ｍｍ、開口（２７）の開口径の大きさを２．４ｍｍのものを用いた場合には、反射回数が１０回、光路長を４４１ｍｍ、ガスセル（１０）の大きさを例えば直径が６０ｍｍ、高さが５０ｍｍの円筒形状のものとして構成することができる。
〔構成例２〕
出射側反射鏡（２０）として焦点距離が３ｍｍのもの、入射側反射鏡（２５）として焦点距離が５ｍｍ、開口（２７）の開口径の大きさが１ｍｍのものを用いた場合には、反射回数が８回、光路長を７３ｍｍ、ガスセル（１０）の大きさを例えば直径が２０ｍｍ、高さが２０ｍｍの円筒形状のものとして構成することができる。
〔構成例３〕
出射側反射鏡（２０）として焦点距離が５ｍｍのもの、入射側反射鏡（２５）として焦点距離が１０ｍｍ、開口（２７）の開口径の大きさが１ｍｍのものを用いた場合には、反射回数が６回、光路長を１０６ｍｍ、ガスセル（１０）の大きさを例えば直径が２０ｍｍ、高さが２０ｍｍの円筒形状のものとして構成することができる。
[Configuration example 1]
When the output side reflecting mirror (20) has a focal length of 15 mm, and the incident side reflecting mirror (25) has a focal length of 25 mm and the aperture (27) has a diameter of 2.4 mm. The number of reflections is 10, the optical path length is 441 mm, and the size of the gas cell (10) can be configured as a cylindrical shape having a diameter of 60 mm and a height of 50 mm, for example.
[Configuration example 2]
When the output-side reflecting mirror (20) has a focal length of 3 mm, and the incident-side reflecting mirror (25) has a focal length of 5 mm and the aperture (27) has an aperture diameter of 1 mm, reflection is performed. The number of times is 8, the optical path length is 73 mm, and the size of the gas cell (10) can be configured as a cylindrical shape having a diameter of 20 mm and a height of 20 mm, for example.
[Configuration example 3]
When the output-side reflecting mirror (20) has a focal length of 5 mm, and the incident-side reflecting mirror (25) has a focal length of 10 mm, and the aperture (27) has an aperture diameter of 1 mm, reflection is performed. The number of times is 6, the optical path length is 106 mm, and the size of the gas cell (10) can be configured as a cylindrical shape having a diameter of 20 mm and a height of 20 mm, for example.
また、所定の多重反射構造を得るために必要とされる構成部材が２つの放物面反射鏡２０，２５のみであり、当該２つの放物面反射鏡２０，２５を焦点の位置を一致させた状態で配置すればよいので、光路の制御が容易であると共に複雑な（煩雑な）光学調整が不要であり、個体差やロット差を生じさせることなしに、所期の機能を有するものを容易に作製することができる。
また、赤外線センサ３０が配置される受光部１４および赤外線光源４０が配置される光源配置部１３がチャンバ部１２と一体に構成されていることにより、チャンバ部１２に対する赤外光の入射条件およびチャンバ部１２から出射される赤外光の、赤外線センサ３０に対する入射条件等を適正な状態にするための調整機構等を設けることが不要であり、このような理由からも、ガスセル１０の小型化を図ることができると共に、複雑な光学調整が不要であって容易に作製することができる。
Further, only the two paraboloidal reflectors 20 and 25 are necessary for obtaining a predetermined multiple reflection structure, and the two paraboloidal reflectors 20 and 25 are made to have the same focal point. It is easy to control the optical path and no complicated (complex) optical adjustment is required, and it has the expected function without causing individual differences or lot differences. It can be easily manufactured.
In addition, since the light receiving unit 14 in which the infrared sensor 30 is disposed and the light source arranging unit 13 in which the infrared light source 40 is disposed are configured integrally with the chamber unit 12, the incident conditions of the infrared light with respect to the chamber unit 12 and the chamber It is not necessary to provide an adjustment mechanism or the like for making the incident conditions of the infrared light emitted from the unit 12 to the infrared sensor 30 in an appropriate state. For this reason, the gas cell 10 can be downsized. In addition to being able to achieve this, complicated optical adjustment is not necessary and it can be easily manufactured.
さらに、２つの放物面反射鏡２０，２５によって多重反射構造が構成されていることにより、ガスセル１０を円筒形状のものとして構成することができ、これにより、放物面反射鏡２０，２５の組配を極めて容易に行うことができると共に、ガスセル１０の作製を容易に行うことができる。 Further, since the multiple reflection structure is configured by the two parabolic reflectors 20 and 25, the gas cell 10 can be configured as a cylindrical shape, and thus the parabolic reflectors 20 and 25 can be formed. The assembly and assembly can be performed very easily, and the gas cell 10 can be easily manufactured.
従って、上記ガスセル１０を備えてなる本発明の赤外線式ガス検知器によれば、基本的に装置全体の小型化を図ることができると共に、所期のガス検知を高い信頼性をもって行うことができ、しかも、ガスセル１０それ自体が小型のものであることにより、ガスの置換が速やかに行われて高い応答性を得ることができる。 Therefore, according to the infrared gas detector of the present invention including the gas cell 10, the entire apparatus can be basically downsized, and desired gas detection can be performed with high reliability. In addition, since the gas cell 10 itself is small, gas replacement can be performed quickly and high responsiveness can be obtained.
以上、本発明の実施形態について説明したが、本発明は上記の実施形態に限定されるものではなく、種々の変更を加えることができる。
例えば、本発明の多重反射型セルを構成する凹面反射鏡の緒元は、例えば測定対象物（例えば特定ガス成分等）の種類と測定濃度範囲など目的に応じて適宜に設定することができる。また、各々の凹面反射鏡は、滑らかな反射面が形成された微小ミラーの集合体により構成されていてもよい。
また、本発明の多重反射型セルは、ガス検知器だけではなく、光の吸光度を利用して、測定対象物物の濃度や純度を測定するための装置に適用することができる。
As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment, A various change can be added.
For example, the specifications of the concave reflecting mirror constituting the multiple reflection type cell of the present invention can be appropriately set according to the purpose such as the type of measurement object (for example, specific gas component) and the measurement concentration range. In addition, each concave reflecting mirror may be constituted by an assembly of minute mirrors on which a smooth reflecting surface is formed.
Moreover, the multiple reflection type cell of the present invention can be applied not only to a gas detector but also to an apparatus for measuring the concentration and purity of an object to be measured using light absorbance.
図１に示す実施例に係る多重反射型セルにおいては、赤外線光源の配置位置は、特に制限されるものではなく、例えば光透過窓に対向した位置に配置されていてもよく、このような形態のものにおいては、赤外線光源からの放射光を反射するための凹面反射鏡をチャンバ部に対して赤外線光源の背面側の位置に配置すればよい。
光検出器が配置された受光部、並びに光源および凹面反射鏡が配置された光源部が多重反射構造が形成されたチャンバ部と一体化された構成であっても、チャンバ部の外部に別個に配置された構成であっても、いずれの構成であってもよい。
In the multiple reflection type cell according to the embodiment shown in FIG. 1, the arrangement position of the infrared light source is not particularly limited. For example, the infrared light source may be arranged at a position facing the light transmission window. In this case, a concave reflecting mirror for reflecting radiated light from the infrared light source may be disposed at a position on the back side of the infrared light source with respect to the chamber portion.
Even if the light receiving part in which the photodetector is arranged and the light source part in which the light source and the concave reflecting mirror are arranged are integrated with the chamber part in which the multiple reflection structure is formed, it is separately provided outside the chamber part. Even if it is the arrangement | positioning arrange | positioned, any structure may be sufficient.
１０ 多重反射型セル（ガスセル）
１１ 外匣
１２ チャンバ部
１３ 光源配置部
１４ 受光部
１５ 入射側窓部材
１６ ガス導入部
１７ ガス排出部
２０ 一方の放物面反射鏡（出射側反射鏡）
２１ 反射面
２５ 他方の放物面反射鏡（入射側反射鏡）
２６ 反射面
２７ 開口
２８ 出射側窓部材
３０ 赤外線センサ
Ｓ ガス導入空間
３５ 凹面反射鏡
４０ 赤外線光源
Ｉ１，Ｉ２ 反射光
Ｆ 焦点
10 Multiple reflection type cell (gas cell)
DESCRIPTION OF SYMBOLS 11 Outer casing 12 Chamber part 13 Light source arrangement | positioning part 14 Light-receiving part 15 Incident side window member 16 Gas introduction part 17 Gas discharge part 20 One paraboloid reflecting mirror (output side reflecting mirror)
21 Reflecting surface 25 The other parabolic reflecting mirror (incident side reflecting mirror)
26 Reflecting surface 27 Opening 28 Emission side window member 30 Infrared sensor S Gas introduction space 35 Concave reflecting mirror 40 Infrared light source I1, I2 Reflected light F Focus
Claims (4)
焦点距離の大きさが互いに異なる２つの放物面反射鏡が焦点の位置が一致する状態で対向して配置されてなることを特徴とする多重反射型セル。 A multi-reflection type cell that multi-reflects radiated light from a light source and enters a photodetector,
2. A multi-reflection type cell, wherein two paraboloidal reflecting mirrors having different focal lengths are arranged to face each other in a state where the focal points coincide with each other.
口径が小さい一方の放物面反射鏡の外縁部分が、外匣に設けられた光透過性を有する枠状の窓部材によって支持されて、２つの放物面反射鏡間に測定対象物が導入される測定対象物導入空間が形成されており、
一方の放物面反射鏡および窓部材によって当該測定対象物導入空間と区画された空間部に光源が配置されていると共に、口径が大きい他方の放物面反射鏡の背面に、当該他方の放物面反射鏡に設けられた窓部材を介して光検出器が配置されていることを特徴とする請求項１に記載の多重反射型セル。 The two parabolic reflectors are of different sizes from each other,
The outer edge portion of one paraboloidal reflector having a small diameter is supported by a light-transmitting frame-shaped window member provided on the outer casing, and the measurement object is introduced between the two paraboloidal reflectors. The measurement object introduction space is formed,
A light source is arranged in a space sectioned from the measurement object introduction space by one parabolic reflector and a window member, and the other parabolic reflector has a large aperture on the back surface of the other parabolic reflector. 2. The multiple reflection type cell according to claim 1, wherein a photodetector is arranged through a window member provided in the object surface reflecting mirror.
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| KR20220073423A (en) * | 2020-11-26 | 2022-06-03 | 주식회사 이엘티센서 | Optical cavity for gas sensor and gas sensor having the same |
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