JP3322466B2 - Humidity sensor - Google Patents
Humidity sensorInfo
- Publication number
- JP3322466B2 JP3322466B2 JP31304893A JP31304893A JP3322466B2 JP 3322466 B2 JP3322466 B2 JP 3322466B2 JP 31304893 A JP31304893 A JP 31304893A JP 31304893 A JP31304893 A JP 31304893A JP 3322466 B2 JP3322466 B2 JP 3322466B2
- Authority
- JP
- Japan
- Prior art keywords
- humidity sensor
- humidity
- sintered body
- lithium titanate
- mol
- 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 - Lifetime
Links
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- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は湿度センサーに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a humidity sensor.
【０００２】[0002]
【従来の技術】湿度に対する伸縮率、抵抗値、容量値な
どの材料特性の変化を利用することで湿度センサーを得
ることができる。このような湿度センサーは、技術の進
歩に伴って、より高精度なものが求められてきており、
精度の高い湿度センサーであれば広範囲の技術に適用で
きることになる。2. Description of the Related Art A humidity sensor can be obtained by utilizing changes in material properties such as expansion ratio, resistance value and capacitance value with respect to humidity. With the advancement of technology, such humidity sensors are required to have higher accuracy.
A highly accurate humidity sensor can be applied to a wide range of technologies.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、既存の
湿度センサーのうち、湿度に対する材料の伸縮によって
湿度を求めるものでは、精度を高くすることが困難であ
り、特にセンサーの小型化を図る場合には、小さくした
分だけ精度が犠牲になるという問題がある。また、抵抗
値や容量値などの電気的に測定できるものは小型化に適
するが、既存の材料を用いた湿度センサーでは、湿度測
定が容易になるような好適な物性が得られていないのが
現状である。However, among the existing humidity sensors, those which obtain the humidity by expansion and contraction of the material with respect to the humidity, it is difficult to increase the accuracy, and particularly when the size of the sensor is reduced. However, there is a problem that accuracy is sacrificed for the reduced size. In addition, those that can be measured electrically such as resistance and capacitance are suitable for miniaturization.However, humidity sensors using existing materials do not have suitable physical properties that facilitate humidity measurement. It is the current situation.
【０００４】[0004]
【課題を解決するための手段】上述の課題を解決せんと
鋭意研究の結果、本件発明者は斜方晶ラムスデライト
（ramsdellite)構造を有するチタン酸リチウム焼結体が
湿度センサーに効果的な物性を有することを見いだし、
ここに、これを用いた新規な湿度センサーとして提案す
るものである。Means for Solving the Problems As a result of earnest studies to solve the above problems, the present inventors have found that a lithium titanate sintered body having an orthorhombic ramsdellite structure is effective for a humidity sensor. To have
Here, a new humidity sensor using this is proposed.
【０００５】斜方晶ラムスデライト構造を有するチタン
酸リチウム焼結体は、酸化リチウムと酸化チタンを所要
の混合比で混合して生成されるものであり、特に、ラム
ズデライト構造を有した１次元イオン導電体として知ら
れるＬｉ2Ｏ−ＴｉＯ2系化合物が選択される。このよう
なＬｉ2Ｏ−ＴｉＯ2系化合物としては、後述するように
その湿度依存性が示されたＬｉ2Ｔｉ3Ｏ7が挙げられ、
さらにＬｉ2ＴｉＯ3、Ｌｉ Ｔｉ2Ｏ4、Ｌｉ4ＴｉＯ4、
Ｌｉ4Ｔｉ5Ｏ12なども挙げられる。[0005] A lithium titanate sintered body having an orthorhombic ramsdellite structure is produced by mixing lithium oxide and titanium oxide at a required mixing ratio, and is particularly one-dimensional having a ramsdellite structure. Li 2 O-TiO 2 based compound known as ionic conductor is selected. Examples of such a Li 2 O—TiO 2 compound include Li 2 Ti 3 O 7, which has been shown to have humidity dependency as described later,
Further, Li 2 TiO 3 , Li Ti 2 O 4 , Li 4 TiO 4 ,
Li 4 Ti 5 O 12 and the like are also included.
【０００６】斜方晶ラムスデライト構造を得るために
は、酸化リチウムと酸化チタンを乾式混合した後、加熱
して完全に溶融させた後、急冷することが必要となる。
例えば、前記Ｌｉ2Ｔｉ3Ｏ7の生成法の一例としては、
Ｌｉ2ＣＯ3とＴｉＯ2を所要の混合比で混ぜ、これに所
要の不純物を添加することも可能であるが、十分に混合
した後乾燥し、この混合物を押し固めて、摂氏１３５０
度で１時間加熱溶融し、次いで大気急冷することで生成
可能である。In order to obtain an orthorhombic ramsdellite structure, it is necessary to dry mix lithium oxide and titanium oxide, heat them completely, and then rapidly cool them.
For example, as an example of the method for producing the Li 2 Ti 3 O 7 ,
It is possible to mix Li 2 CO 3 and TiO 2 at a required mixing ratio, and to add required impurities to the mixture. However, the mixture is thoroughly mixed, dried, and the mixture is compacted to 1350 ° C.
It can be produced by heating and melting at a temperature for one hour and then quenching in air.
【０００７】この生成された斜方晶ラムスデライト構造
のチタン酸リチウムは、例えば摂氏約１１００度、５時
間程度の焼結した後、大気中或いは氷水中にて急冷させ
て焼結体とされる。The resulting lithium titanate having an orthorhombic ramsdellite structure is sintered, for example, at about 1100 ° C. for about 5 hours, and then rapidly cooled in the air or ice water to form a sintered body. .
【０００８】Ｌｉ2Ｏ−ＴｉＯ2系化合物が斜方晶ラムス
デライト構造の単独構造を収率高く得るためには、７
３．０〜７６．０モル％ＴｉＯ2特に好ましくは７３．
５〜７５．５モル％ＴｉＯ2とすれば良いことが知られ
ている。In order for the Li 2 O—TiO 2 type compound to obtain a single structure of the orthorhombic ramsdellite structure with a high yield, it is necessary to prepare
3.0 to 76.0 mol% TiO 2 and particularly preferably 73.
It is known that the content may be 5 to 75.5 mol% TiO 2 .
【０００９】この焼結体に対して、抵抗値を取り出すた
めの一対の電極が設けられる。この電極の材料として
は、例えば白金電極が用いられるが、もちろん、この材
料に限定されるものではない。[0009] A pair of electrodes for extracting a resistance value is provided for the sintered body. As a material of this electrode, for example, a platinum electrode is used, but it is needless to say that the material is not limited to this material.
【００１０】[0010]
【作用】この斜方晶ラムスデライト構造を有するチタン
酸リチウム焼結体は、湿度に対してその抵抗値が依存し
て変化する。この湿度依存性は、後述するような実験結
果より、相対湿度約１０〜８５％の範囲で、ほぼ直線的
に変化するような理想的な関係を示す。この範囲での抵
抗変化は、約６７６〜１２５オームと比較的に大きく、
湿度センサーとして好適である。The lithium titanate sintered body having the orthorhombic ramsdellite structure changes its resistance value depending on humidity. This humidity dependency shows an ideal relationship such that it changes almost linearly in the range of the relative humidity of about 10 to 85% from the experimental results described later. The resistance change in this range is relatively large, about 676-125 ohms,
It is suitable as a humidity sensor.
【００１１】[0011]
【実施例】次に添付図面を参照して本発明の湿度センサ
ーの実施例を詳細に説明する。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a humidity sensor according to an embodiment of the present invention.
【００１２】図１に本実施例の湿度センサーの構成図を
示す。湿度センサー１は、チタン酸リチウム焼結体２と
一対の電極３ａ，３ｂとからなり、平たい円筒形状のチ
タン酸リチウム焼結体２の上面に白金の電極３ａ，３ｂ
が一定の間隔を開けて取り付けられている。FIG. 1 shows a configuration diagram of a humidity sensor according to the present embodiment. The humidity sensor 1 includes a lithium titanate sintered body 2 and a pair of electrodes 3a, 3b, and platinum electrodes 3a, 3b are formed on the upper surface of the flat cylindrical lithium titanate sintered body 2.
Are installed at regular intervals.
【００１３】ここでチタン酸リチウム焼結体２は、斜方
晶ラムスデライト構造を有する焼結体で、Ｌｉ2Ｏ−Ｔ
ｉＯ2系の組成比が７３．０〜７６．０モル％ＴｉＯ2
より好ましくは７３．５〜７５．５モル％ＴｉＯ2とな
るように調整されたものである。The lithium titanate sintered body 2 is a sintered body having an orthorhombic ramsdellite structure, and is composed of Li 2 O—T
The composition ratio of iO 2 system 73.0 to 76.0 mol% TiO 2
More preferably those adjusted to be 73.5 to 75.5 mol% TiO 2.
【００１４】このようなチタン酸リチウム焼結体２の生
成法の具体的な一例としてには、まず、Ｌｉ2ＣＯ3（キ
シダ化学製、特級試薬）とＴｉＯ2（キシダ化学製、特
級試薬；ルチル８９％、アナターゼ１１％）を出発材料
として、ラムスデライト相の単独生成が可能なように、
Ｌｉ2Ｏ／ＴｉＯ2＝１／２．８モル比（化学分析による
成分組成で７４．８モル％ＴｉＯ2）となるように計量
する。これらの材料を十分な乾式混合或いはボールミル
を用いた湿式混合を行い、押し固めた該混合物を摂氏１
３５０度で１時間加熱する。この加熱によって完全に該
混合物溶融させた後、電気炉から取り出して、大気中に
て室温まで急冷する。この時点で、ラムスデライト相の
塊が形成されるが、この塊を粉砕し、この粉砕された粉
を加圧しながらセンサーの形状に合わせた所要の円筒形
状に形成する。次いで、電気炉内で例えば摂氏１１００
度程度の所定温度に加熱され、再び大気中で急冷されて
焼結体とされる。As a specific example of a method for producing such a lithium titanate sintered body 2, first, Li 2 CO 3 (a special grade reagent manufactured by Kishida Chemical) and TiO 2 (a special grade reagent manufactured by Kishida Chemical; (Rutile 89%, anatase 11%) as a starting material so that a single ramsdellite phase can be produced.
Li 2 O / TiO 2 = 1 / 2.8 mole ratio (in chemical composition by chemical analysis 74.8 mol% TiO 2) are weighed so as to. These materials are thoroughly dry-blended or wet-blended using a ball mill, and the compacted mixture is cooled to 1 degree Celsius.
Heat at 350 degrees for 1 hour. After the mixture is completely melted by this heating, the mixture is taken out of the electric furnace and rapidly cooled to room temperature in the atmosphere. At this point, a mass of the ramsdellite phase is formed. The mass is pulverized, and the pulverized powder is formed into a required cylindrical shape according to the shape of the sensor while pressing. Then, in an electric furnace, for example, 1100 degrees Celsius
Is heated to a predetermined temperature, and rapidly cooled again in the atmosphere to obtain a sintered body.
【００１５】この焼結体に白金電極３ａ、３ｂが形成さ
れ、斜方晶ラムスデライト構造を有する焼結体２の抵抗
値の湿度依存性を利用して湿度センサー１が作製され
る。The platinum electrodes 3a and 3b are formed on the sintered body, and the humidity sensor 1 is manufactured by utilizing the humidity dependency of the resistance value of the sintered body 2 having the orthorhombic ramsdellite structure.
【００１６】次に、このような湿度センサー１の機能の
評価のために本件発明者が行った実験について説明す
る。Next, an experiment performed by the present inventor to evaluate the function of the humidity sensor 1 will be described.
【００１７】先ず、前述の如き湿度センサー１を摂氏４
００度で加熱処理し、吸着している水を除去した。次い
で、所定の湿度雰囲気に調整するために、湿度センサー
１は筒状のステンレス容器に挿入され、このステンレス
容器にさらに摂氏１００度、純水１００ミリリットル中
における溶解度量分の所要の各塩化物が投入され、純粋
１００ミリリットルを加えて攪拌し飽和溶液とした。こ
のステンレス容器に測定すべき湿度センサー１をセット
した後、容器を約摂氏２０度の温度に制御された恒温槽
に入れ、そのまま１２時間放置した後、該容器内のセン
サー１を１ＭＨｚの電源及び電流計に電極３ａ、３ｂを
通じて接続し、該電流計を利用して各湿度雰囲気におけ
る抵抗値の測定を行った。First, the humidity sensor 1 as described above is set at 4 degrees Celsius.
Heat treatment was performed at 00 degrees to remove adsorbed water. Next, in order to adjust to a predetermined humidity atmosphere, the humidity sensor 1 is inserted into a cylindrical stainless steel container, and the required chlorides are further added to the stainless steel container at a temperature of 100 degrees Celsius and a solubility amount in 100 ml of pure water. The mixture was charged, 100 ml of pure water was added, and the mixture was stirred to obtain a saturated solution. After the humidity sensor 1 to be measured is set in the stainless steel container, the container is placed in a thermostat controlled at a temperature of about 20 degrees Celsius, and left as it is for 12 hours. The ammeter was connected through the electrodes 3a and 3b, and the resistance value in each humidity atmosphere was measured using the ammeter.
【００１８】図２はその実験の結果を示すグラフであ
る。図２に示すように、抵抗値（対数）は相対湿度約１
０〜８５％の範囲で湿度に対して略直線的に変化し、こ
の湿度範囲内の抵抗変化は約６７６〜１２５オームと比
較的大きく変化しているため、湿度センサーとしての優
れた利用価値があることが確認された。FIG. 2 is a graph showing the results of the experiment. As shown in FIG. 2, the resistance value (logarithm) is about 1 relative humidity.
It changes substantially linearly with respect to humidity in the range of 0 to 85%, and the resistance change in this humidity range is relatively large, about 676 to 125 ohms. It was confirmed that there was.
【００１９】[0019]
【発明の効果】このように本発明の湿度センサーによれ
ば、斜方晶ラムスデライト構造を有するチタン酸リチウ
ム焼結体の湿度依存性を利用して好適な湿度計測が可能
となる。As described above, according to the humidity sensor of the present invention, suitable humidity measurement can be performed by utilizing the humidity dependency of the lithium titanate sintered body having the orthorhombic ramsdellite structure.
【図１】本発明による湿度センサーの一実施例を示す斜
視図である。FIG. 1 is a perspective view showing an embodiment of a humidity sensor according to the present invention.
【図２】本発明による湿度センサーにかかる実験結果を
示すグラフである。FIG. 2 is a graph showing an experimental result of the humidity sensor according to the present invention.
１…湿度センサー ２…焼結体 ３ａ，３ｂ…電極 DESCRIPTION OF SYMBOLS 1 ... Humidity sensor 2 ... Sintered body 3a, 3b ... Electrode
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭52−23694（ＪＰ，Ａ) 特開 昭52−26293（ＪＰ，Ａ) 特開 平７−164097（ＪＰ，Ａ) 特開 昭59−186304（ＪＰ，Ａ) 特開 昭61−43401（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) G01N 27/00 - 27/12 ＪＩＣＳＴファイル（ＪＯＩＳ)──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-52-23694 (JP, A) JP-A-52-26293 (JP, A) JP-A-7-164097 (JP, A) JP-A-59-259 186304 (JP, A) JP-A-61-43401 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) G01N 27/00-27/12 JICST file (JOIS)
Claims (4)
ン酸リチウム焼結体を電極間に配してなることを特徴と
する湿度センサー。1. A humidity sensor comprising a lithium titanate sintered body having an orthorhombic ramsdellite structure disposed between electrodes.
ｉ3Ｏ7 の固溶体であることを特徴とする請求項１記載
の湿度センサー。2. The lithium titanate sintered body is made of Li 2 T
humidity sensor according to claim 1, wherein the i is 3 solid solution of O 7.
ウムに対する酸化チタンの組成比が７３．０モルパーセ
ント以上７６．０モルパーセント以下の範囲にあるもの
であることを特徴とする請求項１又は２記載の湿度セン
サー。3. The lithium titanate sintered body according to claim 1, wherein a composition ratio of titanium oxide to lithium oxide is in a range of 73.0 mol% or more and 76.0 mol% or less. 2. The humidity sensor according to 2.
ウムに対する酸化チタンの組成比が７３．５モルパーセ
ント以上７５．５モルパーセント以下の範囲にあるもの
であることを特徴とする請求項１又は２記載の湿度セン
サー。4. The lithium titanate sintered body according to claim 1, wherein a composition ratio of titanium oxide to lithium oxide is in a range of 73.5 mol% or more and 75.5 mol% or less. 2. The humidity sensor according to 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31304893A JP3322466B2 (en) | 1993-12-14 | 1993-12-14 | Humidity sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31304893A JP3322466B2 (en) | 1993-12-14 | 1993-12-14 | Humidity sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07167811A JPH07167811A (en) | 1995-07-04 |
| JP3322466B2 true JP3322466B2 (en) | 2002-09-09 |
Family
ID=18036583
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP31304893A Expired - Lifetime JP3322466B2 (en) | 1993-12-14 | 1993-12-14 | Humidity sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3322466B2 (en) |
-
1993
- 1993-12-14 JP JP31304893A patent/JP3322466B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07167811A (en) | 1995-07-04 |
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