JPH0119092B2 - - Google Patents
Info
- Publication number
- JPH0119092B2 JPH0119092B2 JP56041679A JP4167981A JPH0119092B2 JP H0119092 B2 JPH0119092 B2 JP H0119092B2 JP 56041679 A JP56041679 A JP 56041679A JP 4167981 A JP4167981 A JP 4167981A JP H0119092 B2 JPH0119092 B2 JP H0119092B2
- Authority
- JP
- Japan
- Prior art keywords
- moisture
- sensitive element
- humidity
- humidity sensing
- sample
- 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
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
- G01N27/121—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid for determining moisture content, e.g. humidity, of the fluid
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Non-Adjustable Resistors (AREA)
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
Description
【発明の詳細な説明】
本発明は、初期感湿特性の時間的劣化が著しく
小さく、長期に亘り高い信頼性を保持する感湿素
子に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a moisture-sensitive element whose initial moisture-sensitive characteristics exhibit significantly little deterioration over time and which maintains high reliability over a long period of time.
各種雰囲気の湿度測定には、感湿素子が広く用
いられている。この感湿素子は、一般に、例えば
MgCr2O4―TiO2系、SnO2―TiO2、TiO2―V2O5
のような金属酸化物の焼結体で周辺雰囲気の湿度
変化に対応して自らの電気抵抗値を変化する多孔
構造の感湿素体と、該感湿素体の表面に一体的に
添着されて該感湿素体の電気抵抗値変化を検出す
るための電極とから構成されている。 Moisture sensing elements are widely used to measure humidity in various atmospheres. This moisture sensitive element is generally, for example,
MgCr 2 O 4 -TiO 2 series, SnO 2 -TiO 2 , TiO 2 -V 2 O 5
A porous moisture sensitive element which is a sintered body of metal oxide and changes its electrical resistance value in response to changes in the humidity of the surrounding atmosphere, and a moisture sensitive element which is integrally attached to the surface of the moisture sensitive element. and an electrode for detecting a change in electrical resistance of the moisture sensitive element.
しかしながら、このような感湿素子において
は、当初の感湿特性（初期感湿特性）が時間の経
緯とともに変化して湿度検出能が低下し、長期に
亘り高い信頼性に裏打ちされた使用ははなはだ困
難であるという欠点があつた。とくに、高湿度雰
囲気下においては、この傾向が顕著であつた。 However, the initial moisture-sensing characteristics (initial moisture-sensing characteristics) of such moisture-sensing elements change over time and the humidity detection ability deteriorates, making it extremely difficult to use them with high reliability over a long period of time. The drawback was that it was difficult. This tendency was particularly noticeable in a high humidity atmosphere.
本発明者らは、上記の問題点を解決するために
鋭意研究を重ねた結果、感湿素子の表面全体を所
定の膜厚を有する疎水性高分子膜で被覆すると、
得られた感湿素子の初期感湿特性の時間的劣化が
改善されるとの事実を見出し、本発明を完成する
に到つた。 As a result of extensive research to solve the above problems, the present inventors found that when the entire surface of a moisture-sensitive element is coated with a hydrophobic polymer film having a predetermined thickness,
The present invention was completed based on the discovery that the temporal deterioration of the initial moisture-sensitive characteristics of the obtained moisture-sensitive element is improved.
本発明は、長期に亘り高い信頼性を保持する感
湿素子のの提供を目的とするものである。すなわ
ち、本発明の感湿素子は、感湿素体と該感湿素体
の表面に一体的に添着された電極とから成る感湿
素子において、該感湿素子の表面全体が、スパツ
タ法により形成された膜厚300〜1500Åの疎水性
高分子膜で被覆されていることを特徴とするもの
である。 An object of the present invention is to provide a moisture-sensitive element that maintains high reliability over a long period of time. That is, the humidity sensing element of the present invention comprises a humidity sensing element and an electrode integrally attached to the surface of the humidity sensing element, and the entire surface of the humidity sensing element is coated by sputtering. It is characterized by being coated with a hydrophobic polymer film having a thickness of 300 to 1500 Å.
本発明において、疎水性高分子膜の働きは必ず
しも充分には解明されていないが、該膜が疎水性
であり、かつ微細な多孔構造を有するため、周囲
雰囲気中水分の感湿素体への浸透量が制限される
ためと考えられる。 In the present invention, although the function of the hydrophobic polymer membrane is not fully understood, since the membrane is hydrophobic and has a fine porous structure, moisture in the surrounding atmosphere does not reach the moisture sensitive element. This is thought to be because the amount of penetration is limited.
本発明にかかる疎水性高分子膜としては、例え
ば、ポリテトラフロロエチレン、ポリエチレン、
ポリスチレン、ポリプロピレン、ポリ塩化ビニ
ル、ポリエステル、の疎水性高分子の薄膜をあげ
ることができるが、、このうち、ポリテトラフロ
ロエチレン膜は、さらに潤滑性が非常によいため
埃等の付着も少なく最も好ましい。 Examples of the hydrophobic polymer membrane according to the present invention include polytetrafluoroethylene, polyethylene,
Thin films of hydrophobic polymers such as polystyrene, polypropylene, polyvinyl chloride, and polyester can be mentioned, but among these, polytetrafluoroethylene film is the most preferred because it has very good lubricity and attracts less dust. preferable.
疎水性高分子膜の膜厚は、用いる高分子の種類
などによつて適宜に選択されるが、あまり薄いと
初期感湿特性の時間的劣化に対する改善効果が得
られず、また、あまりに厚いと感湿特性（相対湿
度とそのときの感湿素子の測定電気抵抗値の関
係）の感度が低下して好ましくない。したがつ
て、膜厚は300〜1500Åの範囲である。 The thickness of the hydrophobic polymer film is appropriately selected depending on the type of polymer used, etc., but if it is too thin, it will not be effective in improving the initial moisture sensitivity characteristics over time, and if it is too thick, it will not be effective. This is undesirable because the sensitivity of the humidity sensitivity characteristic (the relationship between relative humidity and the measured electrical resistance value of the humidity sensing element at that time) decreases. Therefore, the film thickness is in the range of 300-1500 Å.
この疎水性高分子膜を、常法により作製されて
いる感湿素子の表面全体に被覆して、本発明の感
湿素子が得られる。このとき、感湿素子の表面全
体を被覆することが必要で、例えば、特に電極面
を除去した表面のみを被覆した場合には、初期感
湿特性の時間的劣化は改善されないので、全体が
被覆されねばならない。 The moisture-sensitive element of the present invention can be obtained by coating the entire surface of a moisture-sensitive element produced by a conventional method with this hydrophobic polymer film. At this time, it is necessary to coat the entire surface of the moisture-sensitive element. For example, if only the surface from which the electrode surface has been removed is coated, the deterioration of the initial moisture-sensitive characteristics over time will not be improved, so the entire surface is coated. must be done.
疎水性高分子膜の形成方法としては、形成膜厚
のコントロールが正確にできる等の点で、スパツ
タ法が用いられる。 As a method for forming a hydrophobic polymer film, a sputtering method is used because the thickness of the formed film can be accurately controlled.
以下に、本発明を実施例に基づいて説明する。 The present invention will be explained below based on examples.
実施例
酸化亜鉛、酸化チタン、酸化クロムの粉末を、
それぞれモル比で50％、40％、10％秤量し、これ
らを湿式ポツトミルで充分に混合した。ついで、
この混合粉末を120℃で充分に乾燥した後ペレツ
ト状に成形し、空気中で1150℃、２時間加熱処理
して焼結体とした。この気孔率は20％であつた。
得られた焼結体の両面を2000番カーボランターム
研摩材で研摩して直径10mm厚み0.5mmの円板状感
湿素体を作製した。Example: Powders of zinc oxide, titanium oxide, and chromium oxide were
The mole ratios of 50%, 40%, and 10% were weighed out, respectively, and thoroughly mixed in a wet pot mill. Then,
This mixed powder was sufficiently dried at 120°C, formed into pellets, and heat-treated in air at 1150°C for 2 hours to form a sintered body. This porosity was 20%.
Both surfaces of the obtained sintered body were polished with No. 2000 carborane term abrasive to produce a disc-shaped moisture-sensitive element having a diameter of 10 mm and a thickness of 0.5 mm.
得られた感湿素体の両面に常法により金ペース
ト（エレクトロサイエンス・ラボラトリー社製）
を塗布した後、700℃で焼付け、ついでこの焼付
け電極にリード線を熱圧着して感湿素子を作製し
た。 Apply gold paste (manufactured by Electroscience Laboratory) on both sides of the obtained moisture-sensitive element using a conventional method.
After coating the electrode, it was baked at 700°C, and then a lead wire was thermocompression bonded to the baked electrode to fabricate a humidity sensing element.
つぎに、常法のスパツタ蒸着法を適用して、感
湿素子の表面全体に膜厚500Å（試料１）、1000Å
（試料２）、2000Å（試料３）のポリテトラフロロ
エチレン膜を被覆形成した。比較のために、電極
部は被覆せず、感湿素体の部分のみを膜厚1000Å
のポリテトラフロロエチレン膜で被覆した試料も
作製した（試料４）。更に、膜で被覆されていな
い感湿素子を試料５とした。 Next, a conventional sputter deposition method was applied to coat the entire surface of the moisture-sensitive element with a film thickness of 500 Å (sample 1) and 1000 Å.
(Sample 2) and a polytetrafluoroethylene film of 2000 Å (Sample 3) were coated. For comparison, the electrode part was not covered, and only the moisture sensitive element part was coated with a film thickness of 1000 Å.
A sample coated with a polytetrafluoroethylene film was also prepared (Sample 4). Furthermore, Sample 5 was a moisture sensitive element that was not covered with a film.
以上、５種類の感湿素子につき、25℃における
初期感湿素特性を求めた。その結果を第１図に示
した。第１図から明らかなように、感湿素子の表
面がポリテトラフロロエチレン膜で被覆される
と、しかもその膜厚が大きくなると、相対湿度の
変化に対する電気抵抗の変化（感湿特性の感度）
が小さくなり、感度低下を示すことが判明した。 As described above, the initial moisture sensitive element characteristics at 25°C were determined for the five types of moisture sensitive elements. The results are shown in Figure 1. As is clear from Figure 1, when the surface of the humidity-sensitive element is coated with a polytetrafluoroethylene film, and the film thickness increases, the electrical resistance changes with respect to changes in relative humidity (sensitivity of humidity-sensitive characteristics).
was found to be smaller, indicating a decrease in sensitivity.
次に、試料２、試料４、試料５の感湿素子を一
旦、相対湿度90％（40℃）の雰囲気中に種々の時
間放置した後、これを取り出し、相対湿度60％
（25℃）のときの電気抵抗を測定した。ついで、
既に求めてある25℃における初期感湿特性（第１
図）から、上記電気抵抗に相当する相対湿度を読
みとつた。この読み値と60％との差を算出し、こ
れを経時変化率（％）とした。 Next, the humidity sensing elements of Samples 2, 4, and 5 were left in an atmosphere with a relative humidity of 90% (40°C) for various periods of time, and then taken out and placed in an atmosphere with a relative humidity of 60%.
The electrical resistance was measured at (25°C). Then,
Initial moisture sensitivity characteristics at 25℃ that have already been determined (first
Figure), we read the relative humidity corresponding to the above electrical resistance. The difference between this reading value and 60% was calculated, and this was defined as the rate of change over time (%).
相対湿温90％（40℃）中への放置時間（hr）と
上記の経時率化率との関係を第２図に示した。 Figure 2 shows the relationship between the time (hr) of leaving the sample in a relative humidity of 90% (40°C) and the rate of change over time.
第２図から明らかなように、本発明の感湿素子
（試料２）は、従来の感湿素子（試料５）に比べ
て、周囲雰囲気中水分の感湿素体への浸透量が制
限されることがわかり、感湿特性の時間的劣化が
殆んどなく、長期に亘り高い信頼性をもつて使用
できることが判明した。 As is clear from FIG. 2, the humidity sensing element of the present invention (Sample 2) has a limited amount of moisture in the surrounding atmosphere permeating into the humidity sensing element body compared to the conventional humidity sensing element (Sample 5). It was found that there was almost no deterioration of the moisture sensitivity characteristics over time, and that it could be used with high reliability over a long period of time.
第１図は、実施例中に記載した試料１〜５の感
湿素子の25℃における初期感湿特性、第２図は、
試料２（本発明）、試料４（比較例）、試料５（従
来例）の感湿素子の相対湿度90％（40℃）中への
放置時間（hr）と経時変化率との関係をあらわす
ものである。
Figure 1 shows the initial moisture sensitivity characteristics at 25°C of the humidity sensing elements of samples 1 to 5 described in the examples, and Figure 2 shows the
The graph shows the relationship between the time (hr) for which the humidity sensing elements of Sample 2 (present invention), Sample 4 (comparative example), and Sample 5 (conventional example) were left in a relative humidity of 90% (40°C) and the rate of change over time. It is something.
Claims (1)
された電極とから成る感湿素子において、該感湿
素子の表面全体が、スパツタ法により形成された
膜厚300〜1500Åの疎水性高分子膜で被覆されて
いることを特徴とする感湿素子。 ２ 該疎水性高分子膜がポリテトラフロロエチレ
ン膜である特許請求の範囲第１項記載の感湿素
子。[Scope of Claims] 1. A humidity sensing element comprising a humidity sensing element and an electrode integrally attached to the surface of the humidity sensing element, wherein the entire surface of the humidity sensing element is formed by a sputtering method. A moisture-sensitive element characterized by being coated with a hydrophobic polymer film having a thickness of 300 to 1500 Å. 2. The moisture-sensitive element according to claim 1, wherein the hydrophobic polymer film is a polytetrafluoroethylene film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56041679A JPS57156553A (en) | 1981-03-24 | 1981-03-24 | Humidity sensitive element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56041679A JPS57156553A (en) | 1981-03-24 | 1981-03-24 | Humidity sensitive element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57156553A JPS57156553A (en) | 1982-09-27 |
| JPH0119092B2 true JPH0119092B2 (en) | 1989-04-10 |
Family
ID=12615103
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP56041679A Granted JPS57156553A (en) | 1981-03-24 | 1981-03-24 | Humidity sensitive element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57156553A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59102150A (en) * | 1982-12-06 | 1984-06-13 | Mitsubishi Electric Corp | Moisture sensitive material |
| JPS59102149A (en) * | 1982-12-06 | 1984-06-13 | Mitsubishi Electric Corp | Moisture sensitive material |
| JPS60161854U (en) * | 1984-04-05 | 1985-10-28 | 日清紡績株式会社 | humidity sensor |
| DE10335163B3 (en) * | 2003-07-30 | 2005-03-03 | Micronas Gmbh | gas sensor |
| CN105652069A (en) * | 2016-01-29 | 2016-06-08 | 蔡权 | Digital voltage monitor of intelligent transformer substation based on humidity detection |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5626249A (en) * | 1979-08-08 | 1981-03-13 | Mitsubishi Electric Corp | Humidity sensor |
-
1981
- 1981-03-24 JP JP56041679A patent/JPS57156553A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57156553A (en) | 1982-09-27 |
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