JP2692503B2 - Infrared gas sensor - Google Patents
Infrared gas sensorInfo
- Publication number
- JP2692503B2 JP2692503B2 JP4208387A JP20838792A JP2692503B2 JP 2692503 B2 JP2692503 B2 JP 2692503B2 JP 4208387 A JP4208387 A JP 4208387A JP 20838792 A JP20838792 A JP 20838792A JP 2692503 B2 JP2692503 B2 JP 2692503B2
- Authority
- JP
- Japan
- Prior art keywords
- gas
- infrared
- silicon
- cell
- sample cell
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 229910052710 silicon Inorganic materials 0.000 claims description 29
- 239000010703 silicon Substances 0.000 claims description 29
- 238000006243 chemical reaction Methods 0.000 claims description 16
- 229910052751 metal Inorganic materials 0.000 claims description 13
- 239000002184 metal Substances 0.000 claims description 13
- 230000003449 preventive effect Effects 0.000 claims description 7
- 229910045601 alloy Inorganic materials 0.000 claims description 4
- 239000000956 alloy Substances 0.000 claims description 4
- 229910052782 aluminium Inorganic materials 0.000 claims description 4
- 229910052737 gold Inorganic materials 0.000 claims description 4
- 150000002739 metals Chemical class 0.000 claims description 4
- 229910052697 platinum Inorganic materials 0.000 claims description 4
- 229910052709 silver Inorganic materials 0.000 claims description 4
- 239000007789 gas Substances 0.000 description 66
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 29
- 230000035945 sensitivity Effects 0.000 description 12
- 238000010521 absorption reaction Methods 0.000 description 8
- 238000005259 measurement Methods 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- 230000007423 decrease Effects 0.000 description 5
- 238000012544 monitoring process Methods 0.000 description 5
- 238000007740 vapor deposition Methods 0.000 description 5
- 229910002091 carbon monoxide Inorganic materials 0.000 description 4
- 230000003287 optical effect Effects 0.000 description 4
- 238000004458 analytical method Methods 0.000 description 3
- 238000005530 etching Methods 0.000 description 3
- 230000031700 light absorption Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 229910021421 monocrystalline silicon Inorganic materials 0.000 description 3
- 238000004451 qualitative analysis Methods 0.000 description 3
- 238000004445 quantitative analysis Methods 0.000 description 3
- 239000010935 stainless steel Substances 0.000 description 3
- 229910001220 stainless steel Inorganic materials 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 239000003990 capacitor Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000002265 prevention Effects 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 238000004544 sputter deposition Methods 0.000 description 2
- 238000004566 IR spectroscopy Methods 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- -1 Ti N Inorganic materials 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 238000000862 absorption spectrum Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 235000012055 fruits and vegetables Nutrition 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 229910001635 magnesium fluoride Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 238000003908 quality control method Methods 0.000 description 1
- 238000010206 sensitivity analysis Methods 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 239000004071 soot Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000013585 weight reducing agent Substances 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/3504—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing gases, e.g. multi-gas analysis
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
- G01N21/03—Cuvette constructions
- G01N2021/0346—Capillary cells; Microcells
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
- G01N21/03—Cuvette constructions
- G01N21/05—Flow-through cuvettes
Description
【０００１】[0001]
【産業上の利用分野】本発明は、試料セルのガス流路溝
の内壁に高反射膜をコーティングした高感度の測定が可
能な赤外線式ガスセンサに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared gas sensor capable of highly sensitive measurement in which an inner wall of a gas flow channel groove of a sample cell is coated with a highly reflective film.
【０００２】[0002]
【従来の技術】ＣＯ、ＣＯ2等の異なる原子からなるガ
ス分子は、それぞれ固有の振動をしている。そのような
分子に波長を連続的に変化させて赤外線を照射してゆく
と、分子の固有振動と同じ周波数の赤外線が吸収され、
分子の構造に応じたスペクトルが得られる。このスペク
トルから分子の構造を解析する方法を赤外線吸収スペク
トル法という。この赤外線吸収スペクトル法を用いたガ
ス分子の定量、定性分析は赤外線式ガスセンサを用いて
なされる。例えば、ＣＯ、ＣＯ2、ＣＨ4、ＳＯ2、ある
いはＮＯｘ等の異なる原子からなるガス分子の定量、定
性分析を、赤外線式ガスセンサによって行うものであ
る。 2. Description of the Related Art Gas molecules composed of different atoms such as CO and CO 2 have their own vibrations. When such a molecule is irradiated with infrared rays by continuously changing the wavelength, infrared rays having the same frequency as the natural vibration of the molecule are absorbed,
A spectrum corresponding to the structure of the molecule is obtained. The method of analyzing the molecular structure from this spectrum is called infrared absorption spectroscopy. Quantitative and qualitative analysis of gas molecules using this infrared absorption spectrum method is performed using an infrared gas sensor. For example, an infrared gas sensor is used for quantitative and qualitative analysis of gas molecules composed of different atoms such as CO, CO 2 , CH 4 , SO 2 , or NOx.
【０００３】この赤外線式ガスセンサでは、２つの光源
から放射される赤外線が回転セクタにより断続光とな
り、一方は干渉フィルタセルと試料セルとを経て検出器
に達し、他方は干渉フィルタセルと比較セルとを経て検
出器に達する。この際、この試料セルと比較セルを通過
するガスの赤外線吸収の差を測定することにより、ガス
の定量、定性分析が行われる。In this infrared gas sensor, infrared rays emitted from two light sources become intermittent light due to a rotating sector, one of which reaches a detector through an interference filter cell and a sample cell, and the other of which is an interference filter cell and a comparison cell. To reach the detector. At this time, a quantitative and qualitative analysis of the gas is performed by measuring the difference in infrared absorption of the gas passing through the sample cell and the comparison cell.
【０００４】すなわち、上記検出器は、比較側と試料側
の２室に分離されており、この間にコンデンサ膜が設け
られている。また、検出器内には測定成分またはその成
分と同じ赤外線吸収帯をもつガスが封入されているの
で、被測定成分に固有な波長の赤外線だけが吸収され
る。That is, the detector is divided into two chambers, a comparison side and a sample side, and a condenser film is provided between them. Further, since the measurement component or the gas having the same infrared absorption band as that component is enclosed in the detector, only the infrared ray having a wavelength peculiar to the measurement target component is absorbed.
【０００５】比較セルにはＮ2ガス等の不活性ガスが封
入されている。このため、この比較セルでは照射赤外線
の吸収は生じない。一方、試料セルに被測定成分が含ま
れている場合、この成分による赤外線吸収が生じてい
る。この結果、検出器での赤外線の吸収は試料側が比較
側より小さくなる。このときの熱エネルギーの差は、両
室の圧力差となり、上記コンデンサ膜に変位が生じる。
この容量変化を検出し、信号の処理のあと出力信号とし
て取り出す。The comparison cell is filled with an inert gas such as N 2 gas. For this reason, this comparative cell does not absorb the irradiation infrared rays. On the other hand, when the sample cell contains the component to be measured, infrared absorption occurs due to this component. As a result, the absorption of infrared rays by the detector is smaller on the sample side than on the comparison side. The difference in heat energy at this time becomes a pressure difference between the two chambers, and the capacitor film is displaced.
This change in capacitance is detected, processed as a signal, and extracted as an output signal.
【０００６】このような原理の赤外線式ガスセンサの試
料セルおよび比較セルの材質は、感度、堅牢性、およ
び、試料ガスによる腐食性等を考慮して、通常はステン
レスあるいは鉄等が用いられる。The material of the sample cell and the comparison cell of the infrared type gas sensor having such a principle is usually stainless steel, iron or the like in consideration of sensitivity, robustness and corrosiveness due to the sample gas.
【０００７】[0007]
【発明が解決しようとする課題】しかしながら、このよ
うに試料セルおよび比較セルにステンレス等を用いる場
合には試料セル形成のための溶接技術等が必要である。
また、高感度を得るためには、試料セルの体積を大きく
する必要があり、セル自体が、例えば２５０ｍｍ×７０
ｍｍ×７０ｍｍというように大型となる。この結果、試
料ガスの流路が長くなったり、赤外線の光路が長くな
り、分析の応答時間が長い等の欠点を有していた。ま
た、セル重量が例えば０．５〜２．０ｋｇ程度と重いた
め、分析操作の簡便性、容易性に欠けていた。However, when stainless steel or the like is used for the sample cell and the comparison cell as described above, a welding technique or the like for forming the sample cell is required.
Further, in order to obtain high sensitivity, it is necessary to increase the volume of the sample cell, and the cell itself has a size of, for example, 250 mm × 70.
The size is as large as mm × 70 mm. As a result, there are drawbacks such as a long sample gas flow path and a long infrared optical path, which results in a long analysis response time. Further, since the cell weight is heavy, for example, about 0.5 to 2.0 kg, the analytical operation is not simple and easy.
【０００８】そのため、本発明者らは、単結晶シリコン
板材を用いた、小型で軽量な試料セルを開発したが、小
型化が達成される反面、ガス流路が狭小となるため、測
定感度が低下する問題があった。この問題を解消しよう
と、本発明者らは、試料セルのガス流路の内壁に、直
接、反射率の大きなＡｕ、Ａｇといった金属からなる高
反射膜を被着して、ガス流路の内壁における赤外光の乱
反射や光吸収を防止したり、シリコン採用による試料セ
ルの小型化に伴った感度の低下を抑えようと試みた。し
かしながら、ガス流路のシリコン壁面に、直接、金属製
の高反射膜を設けると、高反射膜の金属とシリコンとが
反応するという問題があった。Therefore, the inventors of the present invention have developed a small and lightweight sample cell using a single crystal silicon plate material. However, while miniaturization is achieved, the gas flow path is narrowed, so that the measurement sensitivity is reduced. There was a problem of decline. In order to solve this problem, the inventors of the present invention directly applied a high reflection film made of a metal such as Au or Ag having a large reflectance to the inner wall of the gas channel of the sample cell to form the inner wall of the gas channel. We attempted to prevent diffused reflection and light absorption of infrared light in, and to suppress the decrease in sensitivity due to the miniaturization of the sample cell due to the adoption of silicon. However, when the metal high reflection film is directly provided on the silicon wall surface of the gas flow path, there is a problem that the metal of the high reflection film reacts with silicon.
【０００９】本発明は赤外線式ガスセンサの小型化およ
び軽量化に伴う感度の低下を抑えて、ガス流路壁での赤
外光の乱反射や光吸収の少ない赤外線式ガスセンサを提
供することを、その目的としている。また、高反射膜の
金属と、シリコン製の試料セルのガス流路内壁との反応
を抑制できる赤外線式ガスセンサを提供することを、そ
の目的としている。The present invention provides an infrared gas sensor which suppresses the decrease in sensitivity due to the miniaturization and weight reduction of the infrared gas sensor and has less diffuse reflection and absorption of infrared light on the gas channel wall. Has an aim. Another object of the present invention is to provide an infrared gas sensor capable of suppressing the reaction between the metal of the highly reflective film and the inner wall of the gas channel of the sample cell made of silicon.
【００１０】[0010]
【課題を解決するための手段】このような目的は、下記
の本発明により達成される。すなわち本発明において
は、赤外線式ガスセンサの試料セルのガス流路を形成す
る溝の内壁に、Ａｕ、Ａｇ、Ｐｔ、Ａｌ、または、これ
らの金属の合金を蒸着またはスパッタリングした高反射
膜を設け、しかも高反射膜とガス流路の内壁との間に反
応防止膜を設ける。これらの高反射膜および反応防止膜
を形成することにより、上記の課題は解決される。ここ
でいう反応防止膜としては、例えばＳｉ３Ｎ４、Ｔｉ
Ｎ、ＭｇＦ２などが挙げられる。This and other objects are achieved by the present invention described below. That is, in the present invention, on the inner wall of the groove forming the gas flow path of the sample cell of the infrared gas sensor, Au, Ag, Pt, Al, or a highly reflective film obtained by vapor deposition or sputtering of an alloy of these metals is provided. Moreover, a reaction prevention film is provided between the high reflection film and the inner wall of the gas flow path. The above problems can be solved by forming these highly reflective film and reaction preventing film. Examples of the reaction preventing film here include Si3N4, Ti
N, MgF2, etc. are mentioned.
【００１１】[0011]
【作用】このように試料セルをシリコン製とすること
で、試料セルを小型化することが可能となるが、その結
果、試料セル内を流動する試料ガス量が減少し、ランバ
ート・ベール則にしたがって試料ガスの赤外線吸収量が
減少して感度が低下する。そこで、本発明においては、
シリコン製の試料セルのガス流路内壁に、Ａｕ、Ａｇ、
Ｐｔ、Ａｌあるいはこれらの金属の合金等を用いた高反
射膜を形成する。この反射膜は、９０％以上の反射率を
有するので、ガス流路内壁における赤外光の乱反射や光
吸収が防止され、シリコン製としたことで実現した試料
セルの小型化による感度の低下が抑えられる。また、シ
リコン製の試料セルのガス流路内壁に、直接、金属製の
高反射膜を形成した場合、高反射膜の金属とシリコンと
の反応が起きる。そこで、ガス流路の内壁に高反射膜を
被着するに際しては、まずガス流路の内壁に反応防止膜
を設け、その後、この反応防止膜上に高反射膜を設け
る。これにより、高反射膜の金属とシリコンとの反応を
抑制できる。By making the sample cell made of silicon in this way, the sample cell can be miniaturized, but as a result, the amount of sample gas flowing in the sample cell is reduced and Lambert-Beer law is applied. Therefore, the infrared absorption amount of the sample gas is reduced and the sensitivity is lowered. Therefore, in the present invention,
On the inner wall of the gas passage of the silicon sample cell, Au, Ag,
A highly reflective film is formed using Pt, Al, or an alloy of these metals. Since this reflective film has a reflectance of 90% or more, diffused reflection and light absorption of infrared light on the inner wall of the gas channel are prevented, and the reduction in sensitivity due to the downsizing of the sample cell realized by using silicon is reduced. It can be suppressed. Further, when the metal high reflection film is directly formed on the inner wall of the gas flow path of the silicon sample cell, a reaction between the metal of the high reflection film and silicon occurs. Therefore, when depositing the highly reflective film on the inner wall of the gas flow channel, first, the reaction preventive film is provided on the inner wall of the gas flow channel, and then the highly reflective film is provided on the reaction preventive film. This can suppress the reaction between the metal of the high reflection film and silicon.
【００１２】[0012]
【実施例】以下に本発明に係る赤外線式ガスセンサの実
施例について詳述する。図１〜図３は本発明の一実施例
を示すものである。本実施例においては、シリコン製試
料セル１１の試料ガスのガス流路１２の内壁にＡｕ、Ａ
ｇ、Ｐｔ、Ａｌ、または、これらの金属の合金等を蒸着
あるいはスパッタリングした高反射膜１３を設ける。蒸
着法としては、真空蒸着法、電子ビーム蒸着法等を用い
る。そして、この高反射膜１３の膜厚は８００〜２００
０オングストロームとすることが好ましい。この範囲未
満であると、赤外光を透過し、高い反射率が得られな
い。また、この高反射膜１３の赤外光の反射率は９０％
以上、より好ましくは９９％以上とする。高反射膜１３
が高い反射率を有することにより、ガス流路１２の内壁
での赤外光の乱反射、光吸収を抑えることができ、小型
化による感度の低下を防止することができる。この高反
射膜１３は、照射赤外光の光路となる部分を除いたガス
流路１２内壁全面に形成することが好ましい。なお、こ
の高反射膜１３とシリコン壁との間にＳｉ3Ｎ4を用いた
厚さ０．１〜０．２μｍの反応防止膜１４を介在させる
と、高反射膜１３の金属とシリコンとの反応が抑えら
れ、好適である。反応防止膜１４としては、Ｓｉ3Ｎ4の
ほかにＴｉＮ、ＭｇＦ2等を用いることができる。EXAMPLES Examples of the infrared gas sensor according to the present invention will be described in detail below. 1 to 3 show an embodiment of the present invention. In the present embodiment, Au, A are formed on the inner wall of the gas flow path 12 of the sample gas of the silicon sample cell 11.
A high reflection film 13 is formed by vapor deposition or sputtering of g, Pt, Al, or an alloy of these metals. As the vapor deposition method, a vacuum vapor deposition method, an electron beam vapor deposition method, or the like is used. The thickness of the high reflection film 13 is 800 to 200.
Preferably, the thickness is 0 Å. If it is less than this range, infrared light is transmitted and high reflectance cannot be obtained. Further, the reflectance of infrared light of the high reflection film 13 is 90%.
Or more, more preferably 99% or more. High reflective film 13
By having a high reflectance, it is possible to suppress irregular reflection and light absorption of infrared light on the inner wall of the gas flow path 12, and to prevent a decrease in sensitivity due to miniaturization. It is preferable that the high-reflection film 13 is formed on the entire inner wall of the gas flow path 12 excluding the portion that becomes the optical path of the irradiation infrared light. If a reaction preventive film 14 made of Si 3 N 4 and having a thickness of 0.1 to 0.2 μm is interposed between the highly reflective film 13 and the silicon wall, the metal and silicon of the highly reflective film 13 are separated from each other. This is preferable because the reaction is suppressed. As the reaction prevention film 14, TiN, MgF 2 or the like can be used in addition to Si 3 N 4 .
【００１３】本発明の試料セル１１は、５０×３０×
０．５ｍｍ程度の２枚の単結晶シリコンチップを貼り合
わせて構成している。各シリコン板の表面にはコの字形
状または半楕円形状の溝１５がそれぞれ形成されてい
る。そして、この溝１５が合致するように２枚のシリコ
ン板を貼合わせて試料セル１１が得られる。シリコン板
の貼合わせは、界面１６に自然酸化によって生成したＳ
ｉＯ2層を陽極接合すればよい。この陽極接合により、
表面のＳｉＯ2層の酸素はシリコン板内部に拡散して消
失するのでシリコンセル１１の結晶の均一度は十分保た
れる。また、溝形状は赤外線通過に支障がなければ、任
意の形状は可能であるが、特に矩形や円形が好ましい。
また、その溝１５の断面形状としては矩形に形成する場
合は、例えば異方性エッチング等で行うものとする。そ
して、この溝１５の２つの開口部の一方が試料ガス入口
１７、他方が試料ガス出口１８となる。このガス流路１
２となる溝１５の形成はエッチングによる。そして、こ
の溝１５の幅および深さは１〜５ｍｍおよび５０〜２０
０μｍ程度とする。溝１５の寸法がこの範囲以上だと赤
外光が透過してしまい、この範囲未満であるとガスの測
定体積が少なくなり、測定感度を低下させる。なお、比
較ガス用の流路は、試料ガス流路１２と平行にシリコン
板の表面に同一形状の溝１５をエッチングしてい形成し
ている。The sample cell 11 of the present invention comprises 50 × 30 ×
Two single crystal silicon chips of about 0.5 mm are bonded together. U-shaped or semi-elliptical grooves 15 are formed on the surface of each silicon plate. Then, the two silicon plates are attached so that the grooves 15 are aligned with each other, and the sample cell 11 is obtained. The bonding of the silicon plates is performed by S generated by natural oxidation on the interface 16.
The iO 2 layer may be anodically bonded. By this anodic bonding,
Oxygen in the SiO 2 layer on the surface diffuses and disappears inside the silicon plate, so that the crystal uniformity of the silicon cell 11 is sufficiently maintained. Further, the groove shape may be any shape as long as it does not hinder the passage of infrared rays, but a rectangular shape or a circular shape is particularly preferable.
When the groove 15 is formed to have a rectangular cross-sectional shape, anisotropic etching or the like is used. One of the two openings of the groove 15 serves as the sample gas inlet 17 and the other serves as the sample gas outlet 18. This gas flow path 1
The groove 15 to be 2 is formed by etching. The width and depth of this groove 15 are 1 to 5 mm and 50 to 20.
It is about 0 μm. If the size of the groove 15 is in this range or more, infrared light is transmitted, and if it is less than this range, the measurement volume of gas is reduced and the measurement sensitivity is reduced. The channel for the comparative gas is formed by etching the groove 15 of the same shape on the surface of the silicon plate in parallel with the sample gas channel 12.
【００１４】本発明の赤外線式ガスセンサにおいては、
赤外光は上記ガス流路１２の長手方向に対しての直交面
に配設された光源１９から照射される。この際に、セル
材質のシリコンは赤外光に対して透明であるので照射さ
れた赤外光はシリコン壁を透過してガス流路１２を経て
検出器２０に到達する。したがって、従来のステンレス
製の試料セルがガス流路部分に必要とした赤外光通過窓
は、本発明の試料セル１１においては省略することがで
きる。２１は光チョッパ、２２はフィルタ、２３は光源
側の光チョッパである。また、検出器２０は試料ガスと
同一成分ガスが封入された２室を分離するコンデンサ膜
２４を有して構成されている。このコンデンサ膜２４の
容量変化を検出してガス成分の検出、分析を行うもので
ある。In the infrared gas sensor of the present invention,
Infrared light is emitted from a light source 19 arranged on a plane orthogonal to the longitudinal direction of the gas flow path 12. At this time, since the silicon of the cell material is transparent to infrared light, the irradiated infrared light passes through the silicon wall and reaches the detector 20 via the gas flow path 12. Therefore, the infrared light passage window required for the conventional stainless steel sample cell in the gas channel portion can be omitted in the sample cell 11 of the present invention. Reference numeral 21 is an optical chopper, 22 is a filter, and 23 is a light source side optical chopper. Further, the detector 20 is configured to have a condenser film 24 that separates two chambers in which the same component gas as the sample gas is sealed. The capacitance change of the capacitor film 24 is detected to detect and analyze the gas component.
【００１５】このように作製された本発明の赤外線式ガ
スセンサは、大型ボイラなどのばい煙発生施設の排ガス
の監視、自動車排ガス監視、作業環境の監視、焼成炉の
雰囲気監視および制御、発電ボイラの省エネルギー、燃
焼器具の性能品質管理、および青果物の貯蔵庫の監視等
の用途に使用することができる。The infrared type gas sensor of the present invention thus manufactured is used for monitoring exhaust gas from soot and smoke generating facilities such as large boilers, monitoring automobile exhaust gas, monitoring working environment, monitoring and controlling atmosphere in firing furnace, and energy saving for power generation boiler. It can be used for applications such as performance quality control of burning appliances, and monitoring of fruit and vegetable storage.
【００１６】また、上記試料セル１１の形成は、以下の
ように行う。まず、単結晶シリコンに幅２．５ｍｍ、深
さ１５０μｍのガス流路用の溝を半楕円状にエッチング
し、さらに、この溝内面に０．１５μｍ厚の反応防止膜
を被着する。この後、この反応防止膜の表面に反射膜と
して、Ａｕを１５００オングストローム厚で蒸着する。
そして、この２枚のシリコン板を陽極接合法により貼合
わせる。その上で、５０ｍｍ×３０ｍｍのセルを切り出
す。ここで、セルの赤外光照射面とガス流路面との厚さ
は、１ｍｍである。このようにして作製したシリコンセ
ルの重量は、３．５ｇである。このシリコンセル１１を
例えば非分散型赤外線ガスセンサＶＩＡ−５１０（株式
会社堀場製作所製）に装填し、測定対象ガスとしてＣＯ
2ガスを選び、室温にて赤外線吸収分析を行った。この
際、ＣＯ2ガスの流量は０．２ｌ／ｍｉｎとした。その
ときの検出感度は１ｐｐｍであり、高感度で赤外線吸収
分析が行えることが確認された。The sample cell 11 is formed as follows. First, a groove for a gas flow path having a width of 2.5 mm and a depth of 150 μm is etched into a semi-elliptic shape in single crystal silicon, and a reaction preventive film having a thickness of 0.15 μm is deposited on the inner surface of the groove. After that, Au is vapor-deposited to a thickness of 1500 Å as a reflective film on the surface of the reaction preventive film.
Then, the two silicon plates are bonded together by the anodic bonding method. Then, a cell of 50 mm × 30 mm is cut out. Here, the thickness of the infrared light irradiation surface of the cell and the gas flow path surface is 1 mm. The weight of the silicon cell thus manufactured is 3.5 g. This silicon cell 11 is loaded into, for example, a non-dispersion type infrared gas sensor VIA-510 (manufactured by Horiba, Ltd.), and CO is used as a measurement target gas.
Two gases were selected and infrared absorption analysis was performed at room temperature. At this time, the flow rate of CO 2 gas was 0.2 l / min. The detection sensitivity at that time was 1 ppm, and it was confirmed that infrared absorption analysis can be performed with high sensitivity.
【００１７】[0017]
【発明の効果】本発明の赤外線式ガスセンサの試料セル
は、セルの小型化による感度の低下をガス流路内壁に形
成された高反射膜が補うので、高感度分析が可能であ
る。また、シリコン製の試料セルのガス流路内壁と、高
反射膜との間に設けられた反応防止膜により、高反射膜
の金属とシリコンの反応が抑制できる。In the sample cell of the infrared gas sensor of the present invention, the high reflection film formed on the inner wall of the gas channel compensates for the decrease in sensitivity due to the downsizing of the cell, and therefore high sensitivity analysis is possible. Moreover, the reaction between the metal of the high reflection film and silicon can be suppressed by the reaction preventive film provided between the inner wall of the gas channel of the silicon sample cell and the high reflection film.
【図１】本発明の一実施例に係る赤外線式ガスセンサの
横断面図である。FIG. 1 is a cross-sectional view of an infrared gas sensor according to an embodiment of the present invention.
【図２】本発明の一実施例に係る赤外線式ガスセンサに
用いるシリコンセルの斜視図である。FIG. 2 is a perspective view of a silicon cell used in an infrared gas sensor according to an embodiment of the present invention.
【図３】本発明の一実施例に係るシリコンセルの下半分
の縦断面図である。FIG. 3 is a vertical cross-sectional view of a lower half of a silicon cell according to an embodiment of the present invention.
１１ 試料セル １２ ガス流路 １３ 高反射膜 １５ 溝 ２０ 検出器 11 sample cell 12 gas flow path 13 highly reflective film 15 groove 20 detector
Claims (1)
路を流れる試料ガス中の特定成分を測定する赤外線式ガ
スセンサにおいて、 前記試料セルをシリコン製とし、また前記ガス流路の内
壁にＡｕ、Ａｇ、Ｐｔ、Ａｌ、または、これらの金属の
合金からなる高反射膜を被着するとともに、該高反射膜
と前記ガス流路の内壁との間に反応防止膜を設けたこと
を特徴とする赤外線式ガスセンサ。1. An infrared gas sensor for forming a gas flow path in a sample cell and measuring a specific component in a sample gas flowing through the gas flow path, wherein the sample cell is made of silicon, and an inner wall of the gas flow path is formed. A highly reflective film made of Au, Ag, Pt, Al, or an alloy of these metals was deposited on the above, and a reaction preventive film was provided between the highly reflective film and the inner wall of the gas channel. Infrared gas sensor featuring.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4208387A JP2692503B2 (en) | 1992-07-13 | 1992-07-13 | Infrared gas sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4208387A JP2692503B2 (en) | 1992-07-13 | 1992-07-13 | Infrared gas sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0634544A JPH0634544A (en) | 1994-02-08 |
| JP2692503B2 true JP2692503B2 (en) | 1997-12-17 |
Family
ID=16555425
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4208387A Expired - Fee Related JP2692503B2 (en) | 1992-07-13 | 1992-07-13 | Infrared gas sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2692503B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2392976A (en) * | 2002-09-13 | 2004-03-17 | Delphi Tech Inc | An optical measuring cell with total internal reflection |
| GB2396405B (en) | 2002-12-05 | 2006-03-08 | E2V Tech Uk Ltd | Gas sensors |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE59104604D1 (en) * | 1990-11-26 | 1995-03-23 | Ciba Geigy Ag | Detector cell. |
-
1992
- 1992-07-13 JP JP4208387A patent/JP2692503B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0634544A (en) | 1994-02-08 |
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