JP3097287B2 - Gas sensor and method of manufacturing the same - Google Patents
Gas sensor and method of manufacturing the sameInfo
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- JP3097287B2 JP3097287B2 JP04078860A JP7886092A JP3097287B2 JP 3097287 B2 JP3097287 B2 JP 3097287B2 JP 04078860 A JP04078860 A JP 04078860A JP 7886092 A JP7886092 A JP 7886092A JP 3097287 B2 JP3097287 B2 JP 3097287B2
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Description
【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION
【０００１】[0001]
【産業上の利用分野】本発明はＮＨ3（アンモニアガ
ス）の検出に好適なガスセンサに関する。The present invention relates to a suitable gas sensor for the detection of N H 3 (ammonia gas).
【０００２】[0002]
【従来の技術】ガスの吸脱着により抵抗値が変化する金
属酸化物半導体に電極を接続し、抵抗値を測定すること
でガスの有無を検出するようにした半導体ガスセンサが
従来からガス漏れ警報器等として使用されている。2. Description of the Related Art Conventionally, a semiconductor gas sensor in which an electrode is connected to a metal oxide semiconductor whose resistance value changes due to adsorption and desorption of a gas and the presence or absence of a gas is detected by measuring the resistance value has been known. Used as etc.
【０００３】一方、最近ではトイレやキッチン等の住居
内におけるオートベンチレーション（自動換気）を行な
うためのガスセンサの開発が要望されている。つまり、
トイレやキッチン等の悪臭成分の主なものは、硫化水
素、アンモニア、アミン類及びメルカプタン類であり、
快適な住環境を維持するにはこれらのガス濃度が数ｐｐ
ｂ〜数ｐｐｍの範囲で検出できるセンサが必要とされ
る。しかしながら従来の金属酸化物半導体ガスセンサに
よる検出可能濃度は数百ｐｐｍ以上である。On the other hand, recently, there has been a demand for the development of a gas sensor for performing automatic ventilation (automatic ventilation) in a house such as a toilet or a kitchen. That is,
The main odor components in toilets and kitchens are hydrogen sulfide, ammonia, amines and mercaptans,
To maintain a comfortable living environment, these gas concentrations must be several pp
A sensor that can detect in the range of b to several ppm is required. However, the concentration detectable by a conventional metal oxide semiconductor gas sensor is several hundred ppm or more.
【０００４】そこで、特開昭５８−７９１４９号、特開
昭６２−２１４７号及び特開昭６３−３１３０４８号に
は、金属酸化物半導体としてのＳnＯ2に更に別の金属
（通常酸化物の形態となっている）を添加して、ガス検
出感度を高めるようにした提案がなされている。Accordingly, Japanese Patent Application Laid-Open Nos. 58-79149, 62-2147 and 63-313048 disclose that SnO 2 as a metal oxide semiconductor further contains another metal (usually in the form of an oxide). Has been proposed to increase the gas detection sensitivity.
【０００５】ここで、特開昭５８−７９１４９号には添
加金属酸化物として、Ｓb2Ｏ3、ＴiＯ2、Ａl2Ｏ3、Ｌi2
Ｏ及びＣr2Ｏ3が、特開昭６２−２１４７号には添加金
属として、Ｂ、Ａl、Ｓc、Ｇa、Ｙ、Ｉn及びＴlが、特
開昭６３−３１３０４８号には添加金属酸化物として、
ＰbＯ、ＰdＯ及びＺnＯがそれぞれ開示されている。Here, Japanese Patent Application Laid-Open No. 58-79149 discloses Sb 2 O 3 , TiO 2 , Al 2 O 3 , Li 2
O and Cr 2 O 3, as an additive metal in JP 62-2147, B, Al, Sc, Ga, Y, In and Tl are as additive metal oxides in JP-A-63-313048 ,
PbO, PdO and ZnO are each disclosed.
【０００６】[0006]
【発明が解決しようとする課題】上述したように従来か
ら種々の金属酸化物を添加して、ガス検出感度を高める
試みがなされているが、いずれも被検出ガス（ＮＨ3）
に接触してから定常値になるまでの時間と、被検出ガス
がなくなってからの初期値に戻るまでの回復時間が長
く、且つ低濃度のガスに対する感度が十分ではない。As described above, attempts have been made in the past to increase the gas detection sensitivity by adding various metal oxides, but all of them have been attempted to detect gas (NH 3 ).
And the recovery time until the gas returns to the initial value after the detected gas disappears, and the sensitivity to low concentration gas is not sufficient.
【０００７】[0007]
【課題を解決するための手段】上記課題を解決すべく本
発明は、主体となる金属酸化物に添加物を加えた金属酸
化物半導体に対するガスの吸脱着による抵抗値の変化を
利用したガスセンサにおいて、このガスセンサはアンモ
ニアガスを検出するセンサとし、且つ前記主体となる金
属酸化物をＷＯ 3 とし、添加物をＡuとした。このＡuの
添加量は、０．８wt%とした際に最も感度が高くなる。
また、本発明に係るアンモニアガスの検出方法は、前記
したアンモニアガスセンサを用いることを前提とし、且
つ前記素子温度を３００℃以上とし、検出濃度を５ｐｐ
ｂ〜５０ｐｐｍとするようにした。 SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a gas sensor utilizing a change in resistance value due to adsorption and desorption of gas to a metal oxide semiconductor obtained by adding an additive to a main metal oxide. , This gas sensor
Gold as a sensor for detecting near gas and serving as the main body
The group oxide was WO 3 and the additive was Au. This Au
The sensitivity is highest when the addition amount is 0.8 wt%.
Further, the method for detecting ammonia gas according to the present invention,
It is assumed that the ammonia gas sensor is used.
The element temperature is set to 300 ° C. or more and the detected concentration is set to 5 pp.
b to 50 ppm.
【０００８】[0008]
【作用】ガスセンサの主体となる金属酸化物を従来のＳ
nＯ2から酸性の強いＷＯ3とすることで、ＮＨ3に対する
感度が大幅に向上する。The metal oxide which is the main component of the gas sensor is replaced with the conventional S
By changing the strongly acidic WO 3 from nO 2, the sensitivity to NH 3 is greatly improved.
【０００９】[0009]
【実施例】以下に本発明の実施例を添付図面に基づいて
説明する。ここで、図１及び図２はいずれも本発明に係
るガスセンサの斜視図である。Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, both FIG. 1 and FIG. 2 are perspective views of the gas sensor according to the present invention.
【００１０】図１に示すガスセンサ１は筒状アルミナ管
２に一対のＰt線３，３を巻回し、このＰt線３，３を包
むようにＷＯ3にＰt、Ｒu、Ａu、Ａg、Ｒh及びＰdのう
ちの少なくとも１種を添加してなる多孔質焼結体からな
る金属酸化物半導体層４を形成している。この金属酸化
物半導体層４の製法について以下に述べる。In a gas sensor 1 shown in FIG. 1, a pair of Pt wires 3 and 3 are wound around a cylindrical alumina tube 2 and Pt, Ru, Au, Ag, Rh and Pd are wrapped around WO 3 so as to wrap the Pt wires 3 and 3. The metal oxide semiconductor layer 4 made of a porous sintered body to which at least one of the above is added is formed. The method for producing the metal oxide semiconductor layer 4 will be described below.
【００１１】先ず、パラタングステン酸アンモニウム
｛（ＮＨ4）10Ｗ12Ｏ41・５Ｈ2Ｏ｝を出発原料とし、こ
れを空気中で６００℃．５時間熱分解してＷＯ3の粉末
試料を得る。次いで、この粉末試料にＰt、Ｒu、Ａu、
Ａg、ＲhまたはＰdを添加し、空気中で６００℃．５時
間焼成して得た粉末をビヒクルとともに混練して成形し
た後焼成することで金属酸化物半導体層４を形成する。[0011] First, ammonium paratungstate and {(NH 4) 10 W 12 O 41 · 5H 2 O} as a starting material, which 600 ° C. in air. Pyrolyze for 5 hours to obtain a powder sample of WO 3 . Then, Pt, Ru, Au,
Add Ag, Rh or Pd, and in air at 600 ° C. The metal oxide semiconductor layer 4 is formed by kneading and molding the powder obtained by firing for 5 hours together with the vehicle and then firing.
【００１２】図２に示すガスセンサ１１はアルミナ基板
１２に一対の櫛形Ａu電極１３，１３を焼成により形成
し、このＡu電極１３，１３が接続する金属酸化物半導
体層１４を同じく焼成によりアルミナ基板１２表面に形
成している。この金属酸化物半導体層１４はＷＯ3にＰ
t、Ｒu、Ａu、Ａg、Ｒh及びＰdのうちの少なくとも１種
を添加している。尚、アルミナ等の基板に金属酸化物半
導体層を薄膜状に形成せず、ある程度の厚みの金属酸化
物半導体層に直接電極を埋設してもよい。In the gas sensor 11 shown in FIG. 2, a pair of comb-shaped Au electrodes 13 and 13 are formed on an alumina substrate 12 by firing, and a metal oxide semiconductor layer 14 to which the Au electrodes 13 and 13 are connected is also fired to form an alumina substrate 12. Formed on the surface. This metal oxide semiconductor layer 14 is formed by adding WO 3 to P
At least one of t, Ru, Au, Ag, Rh and Pd is added. Note that the electrode may be directly embedded in the metal oxide semiconductor layer having a certain thickness without forming the metal oxide semiconductor layer in a thin film on a substrate such as alumina.
【００１３】図３はＷＯ3単独からなる素子、ＷＯ3に各
種貴金属（Ｐt、Ｒu、Ａu、Ａg、Ｒh、Ｐd）を0.4ｗｔ
％添加して作製した素子の50ppmＮＨ3に対する温度とガ
ス感度との関係を示すグラフである。この図からＷＯ3
単独では２００℃〜６００℃でのガス感度は５以下であ
るのに対し、上記貴金属を添加した素子のガス感度は３
００℃以上において顕著に高くなることが分る。[0013] Figure 3 is element consisting of WO3 alone, various noble metals WO 3 (Pt, Ru, Au , Ag, Rh, Pd) and 0.4wt
6 is a graph showing the relationship between temperature and gas sensitivity for 50 ppm NH 3 of a device manufactured by adding%. From this figure, WO 3
The gas sensitivity at 200 ° C. to 600 ° C. alone is 5 or less, while the gas sensitivity of the element to which the noble metal is added is 3
It can be seen that the temperature significantly increases at 00 ° C. or higher.
【００１４】また各種貴金属の添加の効果は、図３から
Ｐt＞Ａu＞Ｒh＞Ｐd≒Ａg＞Ｒu＞無添加の順であるが、
Ｐtを添加した素子は、ＮＨ3から空気に切り替えた時の
回復時間が速く、２００℃におけるガス感度が非常に高
い（６１０）にも拘らず、空気中からＮＨ3中に切り替
えた時の応答が非常に遅い問題があった。これに対し、
Ａuは応答性及びガス感度のいずれにおいても良好な結
果が得られた。The effect of the addition of various noble metals is in the order of Pt>Au>Rh> Pd ≒ Ag>Ru> no addition from FIG.
The element added with Pt has a fast recovery time when switching from NH 3 to air, and has a very high gas sensitivity at 200 ° C. (610), but the response when switching from air to NH 3 is achieved. There was a very slow problem. In contrast,
Au gave good results in both response and gas sensitivity.
【００１５】そこで、Ａuを添加した素子の４５０℃に
おけるＮＨ3濃度とガス感度との関係についての実験結
果を図４に示し、また４５０℃でＮＨ3濃度５０ppmまた
は４５０℃の空気中の条件下でのＡu添加量と素子抵抗
値及びガス感度との関係についての実験結果を図５に示
す。[0015] Therefore, under the conditions of NH 3 experimental results on the relationship between the concentration and the gas sensitivity shown in FIG. 4, also NH 3 concentration 50ppm or 450 ° C. in air at 450 ° C. at 450 ° C. of elements with the addition of Au FIG. 5 shows the experimental results on the relationship between the amount of Au added, the element resistance value, and the gas sensitivity.
【００１６】図４からは、ＮＨ3濃度が５ppb〜５０ppm
の間ではＮＨ3濃度の対数とガス感度の対数とが直線関
係になり、またＮＨ3濃度が５ppbの場合にはガス感度が
２．３を示すことが分る。また図５からは、空気中の素
子抵抗値はＡu添加量の増加とともに増加し、０．８ｗ
ｔ％で最大となり、その後わずかに減少し、これに対し
ＮＨ3濃度５０ppmの雰囲気中での素子抵抗値はＡu添加
量の増加とともに徐々に増加することが分る。その結
果、図にも示すようにＡu添加量が０．８ｗｔ％付近に
おいてガス感度が最大になる。FIG. 4 shows that the NH 3 concentration is 5 ppb to 50 ppm.
It can be seen that the logarithm of the NH 3 concentration and the logarithm of the gas sensitivity have a linear relationship between, and that the gas sensitivity shows 2.3 when the NH 3 concentration is 5 ppb. Also, from FIG. 5, the element resistance value in the air increases with an increase in the amount of Au added, and becomes 0.8 watts.
It can be seen that the resistance reaches a maximum at t% and then slightly decreases, whereas the element resistance in an atmosphere having an NH 3 concentration of 50 ppm gradually increases with an increase in the amount of Au added. As a result, as shown in the figure, the gas sensitivity becomes maximum when the amount of Au added is around 0.8 wt%.
【００１７】上記のＡu添加量が約０．８ｗｔ％でガス
感度が最大になるのは、Ａu粒子の分散状態を反映して
いると考えられるので、分散状態が異なってくるコロイ
ド吸着法と含浸法によってＡuを添加した場合の応答曲
線（センサ出力）を図６に示す。ここで、コロイド吸着
法は、パラタングステン酸アンモニウムなどを熱分解し
て得たＷＯ3粉末を上記貴金属のコロイド溶液中に添加
攪拌せしめることで、ＷＯ3粉末表面に前記貴金属を吸
着させる方法であり、この方法で得られた原料粉末をビ
ヒクルとともに混練し、アルミナ管２或いはアルミナ基
板１２等に塗布した後焼成することで金属酸化物半導体
層４，１４を形成したガスセンサを得る。一方、含浸法
は塩化金酸（ＨＡuＣl4）等の貴金属塩の水溶液中にＷ
Ｏ3粉末を添加攪拌し、水分を蒸発させ残渣を乾燥させ
て原料粉末とする方法である。The maximum gas sensitivity when the amount of Au added is about 0.8 wt% is considered to reflect the dispersion state of the Au particles. FIG. 6 shows a response curve (sensor output) when Au was added by the method. Here, the colloid adsorption method is a method in which WO 3 powder obtained by thermally decomposing ammonium paratungstate or the like is added to a colloid solution of the above-mentioned noble metal and stirred to adsorb the noble metal on the surface of the WO 3 powder. The raw material powder obtained by this method is kneaded with a vehicle, applied to the alumina tube 2 or the alumina substrate 12 and baked to obtain a gas sensor in which the metal oxide semiconductor layers 4 and 14 are formed. On the other hand, in the impregnation method, W is added to an aqueous solution of a noble metal salt such as chloroauric acid (HAuCl 4 ).
In this method, O 3 powder is added and stirred, moisture is evaporated, and the residue is dried to obtain a raw material powder.
【００１８】また図６の応答曲線はいずれも４５０℃、
５０ppmＮＨ3に対するものであり、Ａuの添加量はとも
に０．４ｗｔ％とした。図６からはコロイド吸着法によ
って貴金属を添加したガスセンサの方が含浸法によって
貴金属を添加したガスセンサよりも応答特性及びガス感
度のいずれにおいても優れていることが分る。The response curves shown in FIG.
The amount was based on 50 ppm NH 3 , and the amount of Au added was 0.4 wt%. FIG. 6 shows that the gas sensor to which the noble metal is added by the colloid adsorption method is superior to the gas sensor to which the noble metal is added by the impregnation method in both the response characteristics and the gas sensitivity.
【００１９】これは以下の理由によると考えられる。即
ち、含浸法によって調製したＡu粒子は粒子径が大きく
分散度が悪いため酸化活性が低く、またＷＯ3との電子
的相互作用によって形成される電子欠損層がＷＯ3粒子
表面全体を覆っていないのに対し、コロイド吸着法によ
って調製したＡu粒子は上記とは逆に、粒子径が小さく
添加量が適当な範囲であれば、小さなＡu粒子が高分散
しており、またＷＯ3粒子表面全体が電子欠損層で覆れ
ているからと考えられる。This is considered for the following reason. That, Au particles were prepared by impregnation method has a low oxidation activity is poor large degree of dispersion particle size, also electron-deficient layer formed by electronic interaction with the WO 3 does not cover the entire WO 3 particle surface On the other hand, Au particles prepared by the colloid adsorption method, on the contrary, have a small particle diameter and a high dispersion when the amount of addition is in an appropriate range, and the entire surface of the WO 3 particles has a small particle diameter. This is probably because it is covered with the electron-deficient layer.
【００２０】[0020]
【発明の効果】以上に説明した如く本発明によれば、金
属酸化物半導体ガスセンサを構成する主体となる金属酸
化物としてＷＯ3を選定し、これにＰt、Ｒu、Ａu、Ａ
g、Ｒh及びＰdのうちの少なくとも１種を添加したこと
で、ＮＨ3に対するセンサの感度を大幅に高めることが
でき、更に応答速度及び回復速度の双方に優れたガスセ
ンサとすることができる。As described above, according to the present invention, WO 3 is selected as the main metal oxide constituting the metal oxide semiconductor gas sensor, and Pt, Ru, Au, A
By adding at least one of g, Rh and Pd, the sensitivity of the sensor to NH 3 can be greatly increased, and a gas sensor having both excellent response speed and recovery speed can be obtained.
【００２１】また、貴金属の添加方法としてコロイド吸
着法を採用することで、他の添加方法によって得られた
ものに比べてガス感度及び応答特性の良いガスセンサが
得られる。Further, by employing a colloid adsorption method as a method of adding a noble metal, a gas sensor having better gas sensitivity and response characteristics than those obtained by other addition methods can be obtained.
【図１】本発明に係るガスセンサの一例を示す斜視図FIG. 1 is a perspective view showing an example of a gas sensor according to the present invention.
【図２】本発明に係るガスセンサの一例を示す斜視図FIG. 2 is a perspective view showing an example of a gas sensor according to the present invention.
【図３】各種貴金属を添加したＷＯ3素子の温度とガス
感度との関係を示すグラフFIG. 3 is a graph showing the relationship between the temperature and gas sensitivity of a WO 3 element to which various noble metals are added.
【図４】添加物質をＡuとした場合のＮＨ3濃度とガス感
度との関係を示すグラフFIG. 4 is a graph showing a relationship between NH 3 concentration and gas sensitivity when Au is used as an additive.
【図５】Ａu添加量と素子抵抗値及びガス感度との関係
を示すグラフFIG. 5 is a graph showing the relationship between the amount of Au added, the element resistance, and the gas sensitivity.
【図６】コロイド吸着法によって貴金属を添加した場合
と含浸法によって貴金属を添加した場合のセンサ出力を
比較したグラフFIG. 6 is a graph comparing sensor outputs when a noble metal is added by a colloid adsorption method and when a noble metal is added by an impregnation method.
１、１１…ガスセンサ、２、１２…アルミナ、３、１３
…電極、４、１４…金属酸化物半導体層。1, 11: gas sensor, 2, 12: alumina, 3, 13
... electrodes, 4, 14 ... metal oxide semiconductor layers.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 中山 千秋 神奈川県茅ケ崎市本村２丁目８番１号 東陶機器株式会社 茅ケ崎工場内 (56)参考文献 特開 平４−145354（ＪＰ，Ａ) 特開 平４−50756（ＪＰ，Ａ) 特開 昭59−192950（ＪＰ，Ａ) 特開 昭57−74648（ＪＰ，Ａ) 特開 昭52−74392（ＪＰ，Ａ) 特開 昭63−252908（ＪＰ，Ａ) 特開 昭58−180002（ＪＰ，Ａ) 第11回表面科学講演大会講演要旨集、 53頁 1991年12月発行 Ｃｈｅｍ．Ｌｅｔｔ．，1992，ｐ. 639−642 (58)調査した分野(Int.Cl.7，ＤＢ名) G01N 27/12 ＪＩＣＳＴファイル（ＪＯＩＳ)──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Chiaki Nakayama 2-8-1, Honmura, Chigasaki-shi, Kanagawa Prefecture Tochiki Co., Ltd. Chigasaki Factory (56) References JP-A-4-145354 (JP, A) Japanese Unexamined Patent Publication No. Sho 50-50756 (JP, A) JP-A-59-192950 (JP, A) JP-A-57-74648 (JP, A) JP-A-52-74392 (JP, A) JP-A-63-252908 (JP, A) JP, A) JP-A-58-180002 (JP, A) Abstracts of 11th Surface Science Conference, page 53, published December 1991, Chem. Lett. , 1992, p. 639-642 (58) Fields investigated (Int. Cl. 7 , DB name) G01N 27/12 JICST file (JOIS)
Claims (3)
金属酸化物半導体に対するガスの吸脱着による抵抗値の
変化を利用したガスセンサにおいて、前記主体となる金
属酸化物をＷＯ3とし、添加物をＡuとしたことを特徴と
するアンモニアガスセンサ。1. A gas sensor using a change in resistance value due to adsorption and desorption of a gas to a metal oxide semiconductor in which an additive is added to a main metal oxide, wherein the main metal oxide is WO 3 , An ammonia gas sensor, wherein the substance is Au .
において、前記Ａuの添加量は、０．８wt%であることを
特徴とするアンモニアガスセンサ。 2. The ammonia gas sensor according to claim 1,
Wherein the amount of Au added is 0.8 wt%.
A characteristic ammonia gas sensor.
ニアガスセンサを用いたアンモニアガス検出方法においAmmonia gas detection method using near gas sensor
て、前記素子温度を３００℃以上とし、且つ検出濃度をThe element temperature is set to 300 ° C. or more, and the detected concentration is
５ｐｐｂ〜５０ｐｐｍとすることを特徴とするアンモニAmmonium characterized by being 5 ppb to 50 ppm
アガスの検出方法。Agus detection method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04078860A JP3097287B2 (en) | 1991-03-18 | 1992-02-28 | Gas sensor and method of manufacturing the same |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3-78549 | 1991-03-18 | ||
| JP7854991 | 1991-03-18 | ||
| JP04078860A JP3097287B2 (en) | 1991-03-18 | 1992-02-28 | Gas sensor and method of manufacturing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0587760A JPH0587760A (en) | 1993-04-06 |
| JP3097287B2 true JP3097287B2 (en) | 2000-10-10 |
Family
ID=26419609
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP04078860A Expired - Fee Related JP3097287B2 (en) | 1991-03-18 | 1992-02-28 | Gas sensor and method of manufacturing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3097287B2 (en) |
Families Citing this family (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6347997B1 (en) | 1997-10-01 | 2002-02-19 | Brad A. Armstrong | Analog controls housed with electronic displays |
| US6344791B1 (en) | 1998-07-24 | 2002-02-05 | Brad A. Armstrong | Variable sensor with tactile feedback |
| US6222525B1 (en) | 1992-03-05 | 2001-04-24 | Brad A. Armstrong | Image controllers with sheet connected sensors |
| US6343991B1 (en) | 1997-10-01 | 2002-02-05 | Brad A. Armstrong | Game control with analog pressure sensor |
| US6351205B1 (en) | 1996-07-05 | 2002-02-26 | Brad A. Armstrong | Variable-conductance sensor |
| US6415707B1 (en) | 1997-10-01 | 2002-07-09 | Brad A. Armstrong | Analog controls housed with electronic displays for coffee makers |
| US6532000B2 (en) | 1997-10-01 | 2003-03-11 | Brad A. Armstrong | Analog controls housed with electronic displays for global positioning systems |
| US6404584B2 (en) | 1997-10-01 | 2002-06-11 | Brad A. Armstrong | Analog controls housed with electronic displays for voice recorders |
| US6749506B2 (en) * | 2000-01-14 | 2004-06-15 | Sony Computer Entertainment Inc. | Method for changing viewpoints using pressure-sensitive means, recording medium providing software program therefor, and entertainment system |
| TW581701B (en) * | 2000-01-14 | 2004-04-01 | Sony Computer Entertainment Inc | Recording medium, method of using a computer and computer for executing role-playing games |
| EP1403637B1 (en) | 2002-09-25 | 2010-05-12 | NGK Spark Plug Co. Ltd. | Ammonia sensor |
| JP4807561B2 (en) * | 2005-11-22 | 2011-11-02 | 国立大学法人九州大学 | Method for producing metal oxide semiconductor material for gas sensor |
| WO2010024387A1 (en) * | 2008-08-29 | 2010-03-04 | 北陸電気工業株式会社 | Manufacturing method for metal oxide semiconductor material for gas sensor |
| JP6224311B2 (en) * | 2012-11-06 | 2017-11-01 | Ｎｉｓｓｈａ株式会社 | Semiconductor gas sensor element |
| US11531013B2 (en) | 2017-08-09 | 2022-12-20 | Semitec Corporation | Gas sensor, gas detection device, gas detection method, and device provided with gas sensor or gas detection device |
| CN110426420B (en) * | 2019-08-08 | 2020-09-22 | 东北大学 | WO formed by self-assembly of nanorods3NH of microscoon3Gas sensor and preparation method thereof |
| CN112362716A (en) * | 2020-11-05 | 2021-02-12 | 武汉科技大学 | Novel ammonia gas sensor chip and preparation method thereof |
-
1992
- 1992-02-28 JP JP04078860A patent/JP3097287B2/en not_active Expired - Fee Related
Non-Patent Citations (2)
| Title |
|---|
| Ｃｈｅｍ．Ｌｅｔｔ．，１９９２，ｐ．６３９−６４２ |
| 第１１回表面科学講演大会講演要旨集、５３頁 １９９１年１２月発行 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0587760A (en) | 1993-04-06 |
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