JPH0420854A - Gas sensor - Google Patents
Gas sensorInfo
- Publication number
- JPH0420854A JPH0420854A JP12446890A JP12446890A JPH0420854A JP H0420854 A JPH0420854 A JP H0420854A JP 12446890 A JP12446890 A JP 12446890A JP 12446890 A JP12446890 A JP 12446890A JP H0420854 A JPH0420854 A JP H0420854A
- Authority
- JP
- Japan
- Prior art keywords
- gas
- resistance value
- sensor
- temperature
- metal oxide
- 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.)
- Pending
Links
- 239000004065 semiconductor Substances 0.000 claims abstract description 28
- 238000001514 detection method Methods 0.000 claims abstract description 20
- 229910044991 metal oxide Inorganic materials 0.000 claims description 22
- 150000004706 metal oxides Chemical class 0.000 claims description 22
- 239000007789 gas Substances 0.000 description 54
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 29
- NNPPMTNAJDCUHE-UHFFFAOYSA-N isobutane Chemical compound CC(C)C NNPPMTNAJDCUHE-UHFFFAOYSA-N 0.000 description 26
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 16
- 239000001282 iso-butane Substances 0.000 description 13
- 230000035945 sensitivity Effects 0.000 description 9
- 238000010586 diagram Methods 0.000 description 4
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 description 1
- 230000010718 Oxidation Activity Effects 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 229910002090 carbon oxide Inorganic materials 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 1
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical group O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 1
- 229910001887 tin oxide Inorganic materials 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 239000008096 xylene Substances 0.000 description 1
Abstract
Description
【発明の詳細な説明】
〔技術分野〕
本発明は、雰囲気中にガスが存在することを検知するガ
ス検出装置に関するものであり、たとえば、ＬＰガスや
都市ガスのガス漏れ警報器として使用するに適したガス
センサに関する。[Detailed Description of the Invention] [Technical Field] The present invention relates to a gas detection device that detects the presence of gas in an atmosphere, and is suitable for use as a gas leak alarm for LP gas or city gas, for example. Concerning suitable gas sensors.
ガス感応物質として金属酸化物半導体を用いたガスセン
サは既に広く普及しているが、その性質上様々なガス（
イソブタン、プロパン、エタン、メタン、エタノール、
プロピレン、トルエン、キシレン、メタノール、水素、
−酸化炭素等）に感度を有するため、ある特定のガスを
検出したい場合、他のガスによるノイズが大きな問題に
なる。例えば、家庭用のガス漏れ警報器においては、都
市ガスの場合メタンガスにのみ反応することが望ましい
が、設置場所が天井に近いところであるために、水蒸気
や各種蒸気、雑ガスの影響を受けやすい。雑ガスとして
家庭内で最も発生しやすいのはアルコールであるが、一
般のガス検出装置はアルコールに対しても高い感度を有
する。そのため通常はガス選択性を持たせるために、フ
ィルターを付加したりしているが、コスト面において問
題がある・〔目 的〕
本発明の目的は、雰囲気中で発生したガス種を識別する
ことができるガスセンサ、たとえば家庭用ガスの主成分
であるイソブタンあるいはメタンと、家庭内で最もそれ
らに対する雑ガスとなりやすいエタノールとを容易に識
別することができるガスセンサの提供にある。Gas sensors using metal oxide semiconductors as gas-sensitive materials are already widely used, but due to their nature, they are sensitive to various gases (
isobutane, propane, ethane, methane, ethanol,
Propylene, toluene, xylene, methanol, hydrogen,
- carbon oxide, etc.), so if you want to detect a specific gas, noise caused by other gases becomes a big problem. For example, in the case of a gas leak alarm for home use, it is desirable to react only to methane gas in the case of city gas, but since it is installed near the ceiling, it is susceptible to the effects of water vapor, various types of steam, and miscellaneous gases. Although alcohol is the miscellaneous gas that is most likely to be generated in the home, general gas detection devices have high sensitivity to alcohol as well. For this reason, a filter is usually added to provide gas selectivity, but this poses a problem in terms of cost. [Purpose] The purpose of the present invention is to identify the type of gas generated in the atmosphere. An object of the present invention is to provide a gas sensor capable of easily distinguishing, for example, isobutane or methane, which are the main components of household gas, and ethanol, which is most likely to become a miscellaneous gas in the household.
現在、汎用されているガス検知装置は、金属酸化物半導
体の内部に電極を兼ねたヒーターコイルを内蔵させた形
式が採用されている。この形式におけるガス検知は、前
記ヒーターコイルにより、通常３００〜４５０℃に加熱
された金属酸化物半導体の抵抗値が表面でのガス吸着に
より変化することを利用して行われている。Currently, gas detection devices in general use employ a type in which a heater coil that also serves as an electrode is built into a metal oxide semiconductor. This type of gas detection is performed by utilizing the fact that the resistance value of a metal oxide semiconductor heated to usually 300 to 450° C. by the heater coil changes due to gas adsorption on the surface.
一方、前記したように金属酸化物半導体をある温度に加
熱しているのは、雰囲気中に存在する被検ガスと金属酸
化物半導体に吸着している酸素とを反応させるためであ
る。そのため被検ガスの接触酸化活性度の違いにより、
ガスセンサの最適動作温度が異なる。On the other hand, the reason why the metal oxide semiconductor is heated to a certain temperature as described above is to cause the test gas present in the atmosphere to react with the oxygen adsorbed on the metal oxide semiconductor. Therefore, due to the difference in the catalytic oxidation activity of the test gas,
The optimum operating temperature of gas sensors is different.
前記最適動作温度については、たとえばエタノールでは
２５０℃付近で最大感度を持つが、イソブタンでは４５
０℃付近で最大感度を持つ、メタンに対してはイソブタ
ンよりさらに高温側に最大感度を有する。第１図にエタ
ノールとイソブタンに対するガス感度の、センサ動作温
度依存性を示す。Regarding the optimal operating temperature, for example, ethanol has maximum sensitivity around 250°C, but isobutane has maximum sensitivity around 45°C.
It has maximum sensitivity around 0°C, and for methane, it has maximum sensitivity at higher temperatures than isobutane. Figure 1 shows the dependence of the gas sensitivity to ethanol and isobutane on the sensor operating temperature.
なお１図中ガス感度（Ｒａ／８ｇ）のＲａは空気中抵抗
値、 Ｒｇはガス中抵抗値であり、曲線１−ａがエタノ
ール１１０００ｐｐ、曲１！ １−ｂがイソブタン３５
００ｐｐｍのときのセンサ温度との関係を示している。In addition, in Figure 1, Ra of gas sensitivity (Ra/8g) is the resistance value in air, Rg is the resistance value in gas, and curve 1-a is ethanol 11000pp, song 1! 1-b is isobutane 35
The relationship with the sensor temperature at 00 ppm is shown.
そこで１本発明者等は、さらに鋭意研究したところ、金
属酸化物半導体を一定温度で動作させておき、ガスが検
知されると前記金属酸化物半導体の抵抗値がガス種に関
係なく変化するので、その変化量が、ガス検知前の抵抗
値の３０〜８０％に達した時点で、前記金属酸化物半導
体の温度を検知前とは異なる温度に変えることによりガ
スの識別が可能となることを見い出し本発明を完成する
に至った。Therefore, the inventors conducted further intensive research and found that when a metal oxide semiconductor is operated at a constant temperature and a gas is detected, the resistance value of the metal oxide semiconductor changes regardless of the gas type. When the amount of change reaches 30 to 80% of the resistance value before gas detection, the gas can be identified by changing the temperature of the metal oxide semiconductor to a temperature different from that before detection. Heading: The present invention has been completed.
すなわち、本発明は金属酸化物半導体の抵抗値変化を利
用してガス検出を行う金属酸化物半導体ガスセンサにお
いて、金属酸化物半導体よりなるガス検知手段と、該半
導体の抵抗値の変化を読み取る手段と、該抵抗値の変化
量がガス検知前の抵抗値の３０〜８０％に達した時点で
該半導体の温度を変化させる手段とを有することを特徴
とするガスセンサに関する。That is, the present invention provides a metal oxide semiconductor gas sensor that detects gas using a change in the resistance value of a metal oxide semiconductor, which includes a gas detection means made of a metal oxide semiconductor, a means for reading the change in resistance value of the semiconductor, and a gas detection means made of a metal oxide semiconductor; and a means for changing the temperature of the semiconductor when the amount of change in the resistance value reaches 30 to 80% of the resistance value before gas detection.
本発明におけるガス検知手段には金属酸化物半導体が用
いられ、この金属酸化物半導体としては、従来のものを
全て利用し得る。A metal oxide semiconductor is used for the gas detection means in the present invention, and any conventional metal oxide semiconductor can be used.
前記金属酸化物半導体の温度を変化させるには１例えば
前記金属酸化物半導体の内部に電極を兼ねたヒーターコ
イルを内蔵させ、このヒーターコイルに流す電流を制御
することによって行うことができる。The temperature of the metal oxide semiconductor can be changed by, for example, incorporating a heater coil that also serves as an electrode inside the metal oxide semiconductor and controlling the current flowing through the heater coil.
次にセンサ動作温度を変えることにより、たとえばイソ
ブタンあるいはメタンとエタノールとを識別できること
を第２１ｉ！を参照しながら説明する。Next, by changing the sensor operating temperature, it is possible to distinguish, for example, between isobutane or methane and ethanol. This will be explained with reference to.
まず、ガス検出装置の金属酸化物半導体薄膜を４５０℃
程度で動作させておく、ガスを検知（第２図２−ａ）す
ると、金属酸化物半導体がｎ型半導体の場合にはその抵
抗値は減少する。この時点はガス種が何であるかはわか
らないが、その直後にセンサ温度を２５０℃程度まで低
下（第２図２−ｂ）させる、これにより、抵抗値が増加
した場合には、ガス種はイソブタンあるいはメタン（第
２図２−ｃ）であり、さらに減少した場合にはエタノー
ル（第２図２−ｄ）である。First, the metal oxide semiconductor thin film of the gas detection device was heated to 450°C.
If the metal oxide semiconductor is an n-type semiconductor, its resistance value decreases when gas is detected (FIG. 2-2-a). At this point, we do not know what the gas type is, but immediately after that, the sensor temperature is lowered to about 250℃ (Fig. 2-2-b), and if the resistance value increases, the gas type is isobutane. Alternatively, it is methane (Fig. 2, 2-c), and if it is further reduced, it is ethanol (Fig. 2, 2-d).
次に、第３図を参照しながら、センサの温度を変化させ
るシステムの一例を説明する。Next, an example of a system for changing the temperature of the sensor will be described with reference to FIG.
センサ電圧として適当な一定電圧Ｖｓを印加しておく。An appropriate constant voltage Vs is applied as a sensor voltage.
オペアンプＡｌの出力には、センサの電導度に比例した
電圧が表われる。つまりガス検知によりｇ力が変化する
。Ａ２はコンパレータであり、 Ｖｒｅｆの値を、ガス
検知前出力に対し、 ３０〜８０％変化した時に、出力
が変化するように設定しておく、この出力信号はヒータ
ー制御回路に入り、ヒーター電圧あるいはヒーター電流
を制御してセンサ温度を変化させる。センサ温度変化前
後のＡ１出力を検出回路で比較することにより、ガス種
を識別できる。A voltage proportional to the conductivity of the sensor appears at the output of the operational amplifier Al. In other words, the g-force changes due to gas detection. A2 is a comparator, and it is set so that the output changes when the Vref value changes by 30 to 80% of the output before gas detection. This output signal enters the heater control circuit and changes to the heater voltage or The sensor temperature is changed by controlling the heater current. The gas type can be identified by comparing the A1 output before and after the sensor temperature change using the detection circuit.
金属酸化物半導体を酸化スズとする。 The metal oxide semiconductor is tin oxide.
まず４５０℃程度で動作させておくと、その抵抗値は１
００にΩ程度となっている。ガスを検知し、その抵抗値
が５ＯＫΩ程度となった時点で、ヒーターに流す電流を
減少させ、温度を２５０℃程度にする。First, if you operate it at around 450℃, the resistance value will be 1
00 to about Ω. When gas is detected and the resistance value reaches approximately 5 OKΩ, the current flowing through the heater is reduced to bring the temperature to approximately 250°C.
ガス種がイソブタンあるいはメタンの場合には、抵抗値
は５０にΩよりも増加する。エタノールの場合には５０
にΩよりも減少する。When the gas species is isobutane or methane, the resistance value increases to 50Ω. 50 for ethanol
decreases more than Ω.
本発明によれば、ガスを検知し抵抗値が変化した直後に
センサの動作温度を変えて、その抵抗値の増減を見るこ
とができるので、たとえばイソブタンあるいはメタンと
エタノールとを識別することができる。According to the present invention, it is possible to change the operating temperature of the sensor immediately after gas is detected and the resistance value changes to see an increase or decrease in the resistance value, so it is possible to distinguish between isobutane or methane and ethanol, for example. .
第１図は、センサ温度変化によるエタノールとイソブタ
ンのガス感度の曲線図、第２図は。
センサ温度を降下させたときの経時変化で示すセンサ抵
抗値の一曲線図、第３図は、センサの温度を変化させる
システムの説明図である。
１−ａ・・・エタノール曲線
１−ｂ・・・イソブタン曲線
２−ａ・・・ガス検知点
２−ｂ・・・センサ温度降下点Figure 1 is a curve diagram of the gas sensitivity of ethanol and isobutane due to sensor temperature changes, and Figure 2 is a curve diagram of the gas sensitivity of ethanol and isobutane. FIG. 3 is a curve diagram of the sensor resistance value showing the change over time when the sensor temperature is lowered, and is an explanatory diagram of the system for changing the sensor temperature. 1-a...Ethanol curve 1-b...Isobutane curve 2-a...Gas detection point 2-b...Sensor temperature drop point
Claims (1)
を行う金属酸化物半導体ガスセンサにおいて、金属酸化
物半導体よりなるガス検知手段と、該半導体の抵抗値の
変化を読み取る手段と、該抵抗値の変化量がガス検知前
の抵抗値の３０〜８０％に達した時点で該半導体の温度
を変化させる手段とを有することを特徴とするガスセン
サ。1. A metal oxide semiconductor gas sensor that detects gas by using a change in the resistance value of a metal oxide semiconductor, which includes a gas detection means made of a metal oxide semiconductor, a means for reading a change in the resistance value of the semiconductor, and the resistor. A gas sensor comprising means for changing the temperature of the semiconductor when the amount of change in value reaches 30 to 80% of the resistance value before gas detection.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12446890A JPH0420854A (en) | 1990-05-15 | 1990-05-15 | Gas sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12446890A JPH0420854A (en) | 1990-05-15 | 1990-05-15 | Gas sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0420854A true JPH0420854A (en) | 1992-01-24 |
Family
ID=14886274
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12446890A Pending JPH0420854A (en) | 1990-05-15 | 1990-05-15 | Gas sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0420854A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5629474A (en) * | 1993-03-30 | 1997-05-13 | Keele University | Production of a sensor for carbon monoxide or water vapor including a semi conductor metallic oxide, catalyst, and rheological agent |
| JP2004271263A (en) * | 2003-03-06 | 2004-09-30 | Osaka Gas Co Ltd | Gas sensing apparatus |
| JP2016188832A (en) * | 2015-03-30 | 2016-11-04 | 大阪瓦斯株式会社 | Gas detection device |
-
1990
- 1990-05-15 JP JP12446890A patent/JPH0420854A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5629474A (en) * | 1993-03-30 | 1997-05-13 | Keele University | Production of a sensor for carbon monoxide or water vapor including a semi conductor metallic oxide, catalyst, and rheological agent |
| JP2004271263A (en) * | 2003-03-06 | 2004-09-30 | Osaka Gas Co Ltd | Gas sensing apparatus |
| JP2016188832A (en) * | 2015-03-30 | 2016-11-04 | 大阪瓦斯株式会社 | Gas detection device |
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