JPS6093338A - Measuring circuit of humidity sensor of electric resistance type - Google Patents
Measuring circuit of humidity sensor of electric resistance typeInfo
- Publication number
- JPS6093338A JPS6093338A JP20081283A JP20081283A JPS6093338A JP S6093338 A JPS6093338 A JP S6093338A JP 20081283 A JP20081283 A JP 20081283A JP 20081283 A JP20081283 A JP 20081283A JP S6093338 A JPS6093338 A JP S6093338A
- Authority
- JP
- Japan
- Prior art keywords
- humidity sensor
- circuit
- electric resistance
- voltage
- rectangular wave
- 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
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
- G01N27/122—Circuits particularly adapted therefor, e.g. linearising circuits
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)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Abstract
Description
【発明の詳細な説明】
〔発明の利用分野〕
本発明は電気抵抗式湿度センサの測定回路に係り、特に
矩形波発振回路の出力電圧をローパスフィルタ通過後に
湿度センサに印加する構成の測定回路に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a measurement circuit for an electrical resistance type humidity sensor, and more particularly to a measurement circuit configured to apply the output voltage of a rectangular wave oscillation circuit to a humidity sensor after passing through a low-pass filter. .
従来の電気抵抗式湿度センサには正弦波を印加していた
ので、発振回路の構成が複雑でしかも発振の安定性砂よ
くないという欠点があった。Conventional electrical resistance humidity sensors apply a sine wave, which has the drawbacks of complex oscillation circuit configurations and poor oscillation stability.
本発明の目的は、構成要簡単で長期安定性のある電気抵
抗式湿度センサ用測定回路を提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to provide a measuring circuit for an electrical resistance humidity sensor that is simple in construction and has long-term stability.
有機高分子の感湿膜に使用する電気抵抗式湿度センサに
矩形波電圧を印加する回路構成にして長時間使用すると
、湿度センサの特性が徐々に変化すること及び矩形波励
起にすると湿度センサに高周波のスパイク電圧が印加し
易いことがわかった。When an electrical resistance humidity sensor used for an organic polymer moisture-sensitive film is configured to apply a square wave voltage and is used for a long period of time, the characteristics of the humidity sensor gradually change. It was found that high frequency spike voltages can be easily applied.
このスパイク電圧が発生しないようにするには、矩形波
電圧の立上り及び立上りの波形をローパスフィルタによ
ってなだらかにすればよい。In order to prevent this spike voltage from occurring, the waveform of the rise and rise of the rectangular wave voltage may be smoothed by a low-pass filter.
以下、本発明の一実施例を第１図、第２図、第３図、第
４図、第５図により説明する。An embodiment of the present invention will be described below with reference to FIGS. 1, 2, 3, 4, and 5.
第１図は有機高分子の感湿膜を使用する電気抵抗式湿度
センサの平面図、第２図は第１図のＡ−Ａ′線における
断面図、第３図は上記湿度センサの相対湿度に対する電
気抵抗値の特性例を示す。Figure 1 is a plan view of an electrical resistance humidity sensor that uses an organic polymer moisture-sensitive film, Figure 2 is a cross-sectional view taken along line A-A' in Figure 1, and Figure 3 is the relative humidity of the humidity sensor. An example of the characteristics of the electrical resistance value is shown below.
電気抵抗式湿度センサ１の構造例を第１図及び第２図で
説明する。第２図において、１１は酸化アルミニウムか
らなる基板であり、この基１ｆｉｌｌ上に金で形成され
たｒ！ＪＩＶＸの狭い一対の櫛形電極１２が相互に嵌合
状態で配設される。この電極１２の間には、周囲の湿度
に応じて電気抵抗値が変化する有機高分子の感湿膜１３
を塗布している。感湿材としてはスルホン化したポリス
チレン、カチオニツクモノマ（例えばメタクリルオキシ
エチルトリメチルアンモニウムクロライド）とビニルモ
ノマ（例えばメチルメタクリレート）の共重合体などが
使用される。この構造における寸法の一例は下記のとお
りである。酸化アルミニウム基板Ｊ１は１５−角以下、
厚みは１ ｍｎ以下、電極■２の厚みはｌＯμｍ程度、
間隙は約０．２町、有機高分子の感湿膜１３の厚みも約
１０μｍである。この湿度センサの初期特性の一例は第
３図のＢに示すとおりである。これは周波数１ ｋＨｚ
の正弦波で測定した結果であり、電気抵抗値は相対湿度
に対応してほぼ指数関数的に変化する。なお、周波数１
００Ｈｚと１０ｋＨｚで測定した結果を第３図に示す値
とよく一致しており周波数依存性は少ない。A structural example of the electrical resistance type humidity sensor 1 will be explained with reference to FIGS. 1 and 2. In FIG. 2, 11 is a substrate made of aluminum oxide, and r! is formed of gold on one fill of this substrate. A pair of narrow comb-shaped electrodes 12 of JIVX are disposed in a mutually fitted state. Between the electrodes 12 is an organic polymer moisture-sensitive film 13 whose electrical resistance changes depending on the surrounding humidity.
is applied. As the moisture sensitive material, sulfonated polystyrene, a copolymer of a cationic monomer (for example, methacryloxyethyltrimethylammonium chloride) and a vinyl monomer (for example, methyl methacrylate), etc. are used. An example of dimensions in this structure is as follows. The aluminum oxide substrate J1 is 15-square or less,
The thickness is 1 mm or less, the thickness of electrode 2 is about 10 μm,
The gap is about 0.2 mm, and the thickness of the organic polymer moisture sensitive film 13 is about 10 μm. An example of the initial characteristics of this humidity sensor is as shown in B of FIG. This is a frequency of 1 kHz
The electrical resistance value changes almost exponentially in response to relative humidity. In addition, frequency 1
The results measured at 00 Hz and 10 kHz agree well with the values shown in FIG. 3, and there is little frequency dependence.
この電気抵抗式湿度センサの測定回路として、第４図に
本発明になる回路のブロック図、第５図にその具体的な
一実施例を示す。As a measuring circuit for this electrical resistance type humidity sensor, FIG. 4 shows a block diagram of the circuit according to the present invention, and FIG. 5 shows a specific embodiment thereof.
第４図において、２は矩形波発振回路、３はローパスフ
ィルタ、４は直流遮断用のコンデンサ、５は整流回路、
６は直流信号処理回路、７は直流電源である。直流電源
７からの電圧供給によって２の矩形波発振回路は矩形波
の出力電圧を発生する。この矩形波の出力電圧をローパ
スフィルタ３に印加し、矩形波の立上り、立下の波形を
なだらかにする。この波形整形した交流電圧を湿度セン
サｌに印加する。この時に交流電圧に重畳する直流電圧
が湿度センサ１に印加いないようにするため、コンデン
サ４で直流を遮断する。湿度センサ】の抵抗値に対応す
る交流信号を整流回路５で直流信号に変換後、この直流
信号を直流信号処理回路６で制御用のオンオフ信号や指
間用のアナログ信号などに変換して出力信号とする。従
って、周囲の相対湿度に対応して湿度センサ１の電気抵
抗が変化し、上記の測定回路によって信号処理されて相
対湿度に対応する直流出力信号が得られる。In Fig. 4, 2 is a rectangular wave oscillation circuit, 3 is a low-pass filter, 4 is a DC cutoff capacitor, 5 is a rectifier circuit,
6 is a DC signal processing circuit, and 7 is a DC power supply. The rectangular wave oscillation circuit 2 generates a rectangular wave output voltage by supplying voltage from the DC power supply 7. This rectangular wave output voltage is applied to a low-pass filter 3 to smooth the rise and fall of the rectangular wave. This waveform-shaped AC voltage is applied to the humidity sensor l. At this time, in order to prevent the DC voltage superimposed on the AC voltage from being applied to the humidity sensor 1, the capacitor 4 interrupts the DC voltage. After the AC signal corresponding to the resistance value of the humidity sensor is converted into a DC signal by the rectifier circuit 5, this DC signal is converted into an on/off signal for control, an analog signal for between fingers, etc. by the DC signal processing circuit 6, and output. Signal. Therefore, the electrical resistance of the humidity sensor 1 changes in accordance with the surrounding relative humidity, and the signal is processed by the above measurement circuit to obtain a DC output signal corresponding to the relative humidity.
第５図に示す具体的な一実施例でさらに詳細に説明する
。矩形波発振回路２において、２１は演算増幅器または
コンパレータ、２２はコンデンサ、２３．２４，２５，
２６，２７．２８は抵抗であり、無安定マルチバイブレ
ータと称される発振回路を構成する。その発振周波数は
主にコンデンサ２２と抵抗２３の値によって定まる。ロ
ーパスフィルタ３は抵抗３１とコンデンサ３２からなる
簡単な構成であり、矩形波発振回路２の出力電圧の低周
波分のみ通過させるので、」二記矩形波の立上りがなだ
らかな波形になり、スパイク波形の発生を阻止できる。This will be explained in more detail using a specific example shown in FIG. In the rectangular wave oscillation circuit 2, 21 is an operational amplifier or a comparator, 22 is a capacitor, 23, 24, 25,
26, 27, and 28 are resistors, which constitute an oscillation circuit called an astable multivibrator. The oscillation frequency is mainly determined by the values of the capacitor 22 and resistor 23. The low-pass filter 3 has a simple configuration consisting of a resistor 31 and a capacitor 32, and passes only the low frequency component of the output voltage of the rectangular wave oscillation circuit 2, so that the rising edge of the rectangular wave becomes a gentle waveform, resulting in a spike waveform. can be prevented from occurring.
この交流電圧はコンデンサ４、湿度センナｌの抵抗値、
抵抗３３で分圧され、抵抗３３に印加する交流電圧が整
流回路５で整流される。トランジスタ５１はエミッタフ
ォロアの接続であり、入力インピーダンスを大きくして
、上記の分圧比に影響を及ぼさないように動作すると共
に、ベース・エミッタの整流特性で入力信号を整流する
。エミッタに接続する抵抗５２、コンデンサ５３を含め
た回路構成で交流入力信号の最大値に対する直流電圧値
を保持する尖頭値整流回路である。図示の直流信号処理
回路６は、オンオフ信号を得る場合の構成例であり、直
流電源７の電圧を抵抗６２，６３．６４で分圧した設定
電圧と、コンデンサ５３の両端の電圧どの大小関係を演
算増幅器またはコンパレータ６Ｉで比較して、高レベル
または低レベルの出力信号を発生する。従って、湿度セ
ンサｌの抵抗値に対応したオンオフ信号が出力信号とし
て得らオしる。This AC voltage is the resistance value of capacitor 4, humidity sensor l,
The AC voltage that is divided by the resistor 33 and applied to the resistor 33 is rectified by the rectifier circuit 5 . The transistor 51 has an emitter follower connection, operates to increase the input impedance so as not to affect the above-mentioned voltage division ratio, and rectifies the input signal using base-emitter rectification characteristics. This is a peak value rectifier circuit that maintains a DC voltage value relative to the maximum value of an AC input signal with a circuit configuration including a resistor 52 and a capacitor 53 connected to the emitter. The illustrated DC signal processing circuit 6 is a configuration example for obtaining an on/off signal, and the magnitude relationship between the set voltage obtained by dividing the voltage of the DC power supply 7 by resistors 62 and 63, and the voltage across the capacitor 53 is determined. A comparison is made by an operational amplifier or comparator 6I to generate a high level or low level output signal. Therefore, an on/off signal corresponding to the resistance value of the humidity sensor 1 is obtained as an output signal.
以上は無安定マルチバイブレータの矩形波発１１１塁回
路、抵抗とコンデンサからなるローパスフィルタ回路、
有機高分子の感湿膜を使用した電気抵抗式湿度センサに
ついて説明したか、これらに限定されないのは勿論であ
る。The above is an astable multivibrator square wave generation 111 circuit, a low pass filter circuit consisting of a resistor and a capacitor,
Although the electrical resistance type humidity sensor using an organic polymer moisture-sensitive film has been described, it is needless to say that the present invention is not limited thereto.
本発明によれば、ローパスフィルタ回路により矩形波電
圧の立上り、立下り波形になだらかに整形しち後に、電
気抵抗式湿度センサに上記電圧を印加する測定回路であ
るので、高周波のスパイク電圧が発生せず、しかも回路
構成が簡単、特に矩形波発振回路は正弦波発振回路より
簡単な構成にできるので長期信頼性のある測定回路を得
ることができる効果がある。According to the present invention, since the measurement circuit applies the voltage to the electrical resistance humidity sensor after shaping the rectangular wave voltage into rising and falling waveforms using a low-pass filter circuit, a high-frequency spike voltage is generated. Moreover, since the circuit configuration is simple, and in particular, the rectangular wave oscillation circuit can have a simpler configuration than the sine wave oscillation circuit, it is possible to obtain a measuring circuit with long-term reliability.
第】図は有機高分子の感湿膜を使用する電気抵抗式湿度
センサの平面図、第２図は第１図の八−Ａ′部説明図、
第３図は上記湿度センサの相対湿度に対する電気抵抗値
の特性例を示すグラフ、第４図は本発明になるａｌｌｌ
定回路のブロック図、第５図はその具体的に−・実施例
を示す慴成図である。
ｌ・・・電気抵抗式湿度センサ、２・−・矩形波発振回
路、３・・・ローパスフィルタ、４・・・コンデンサ、
５・整第１区
オＨ夕１ 匿Ｌ（％）Figure 2 is a plan view of an electrical resistance humidity sensor using an organic polymer moisture-sensitive film, Figure 2 is an explanatory view of section 8-A' in Figure 1,
FIG. 3 is a graph showing an example of the characteristics of the electrical resistance value with respect to the relative humidity of the humidity sensor, and FIG.
FIG. 5 is a block diagram of the constant circuit, and is a schematic diagram showing a concrete example thereof. l... Electric resistance type humidity sensor, 2... Rectangular wave oscillation circuit, 3... Low pass filter, 4... Capacitor,
5. Preparation 1st Ward OH Yu 1 Hidden L (%)
Claims (1)
用コンデンサと整流回路と直流信号処理と直流電源より
成る電気抵抗式湿度センサの測定回路において、前記直
流電源からの電圧印加により前記矩形波発振回路の発生
ずる矩形波電圧を、前記ローパスフィルタ回路を通過さ
せて矩形波の立上り、立」ニリの波形をなだらかにした
後に電気抵抗式湿度センサに印加することを特徴とする
電気抵抗式湿度センサの測定回路。(2) In a measurement circuit for an electrical resistance humidity sensor consisting of a rectangular wave oscillation circuit, a low-pass filter circuit, a DC cutoff capacitor, a rectifier circuit, a DC signal processor, and a DC power supply, the rectangular wave oscillation circuit is generated by applying voltage from the DC power supply. The electric resistance type humidity sensor is characterized in that the generated rectangular wave voltage is applied to the electric resistance type humidity sensor after passing the generated rectangular wave voltage through the low-pass filter circuit to smooth out the waveform of the rise, rise and rise of the rectangular wave. measurement circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20081283A JPS6093338A (en) | 1983-10-28 | 1983-10-28 | Measuring circuit of humidity sensor of electric resistance type |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20081283A JPS6093338A (en) | 1983-10-28 | 1983-10-28 | Measuring circuit of humidity sensor of electric resistance type |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6093338A true JPS6093338A (en) | 1985-05-25 |
Family
ID=16430601
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20081283A Pending JPS6093338A (en) | 1983-10-28 | 1983-10-28 | Measuring circuit of humidity sensor of electric resistance type |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6093338A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0357950A (en) * | 1989-07-26 | 1991-03-13 | Nissan Motor Co Ltd | Electrostatic capacity sensor circuit |
| CN103308569A (en) * | 2013-05-14 | 2013-09-18 | 哈尔滨工业大学 | Singlechip integrated type carbon nano tube humidity sensor based on sine wave stimulation |
| JP2013213760A (en) * | 2012-04-03 | 2013-10-17 | Toshiba Corp | Start-up range monitor calibration system |
| JP2018179757A (en) * | 2017-04-13 | 2018-11-15 | 株式会社日立製作所 | Humidity detection element and hygrometer |
-
1983
- 1983-10-28 JP JP20081283A patent/JPS6093338A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0357950A (en) * | 1989-07-26 | 1991-03-13 | Nissan Motor Co Ltd | Electrostatic capacity sensor circuit |
| JP2013213760A (en) * | 2012-04-03 | 2013-10-17 | Toshiba Corp | Start-up range monitor calibration system |
| CN103308569A (en) * | 2013-05-14 | 2013-09-18 | 哈尔滨工业大学 | Singlechip integrated type carbon nano tube humidity sensor based on sine wave stimulation |
| JP2018179757A (en) * | 2017-04-13 | 2018-11-15 | 株式会社日立製作所 | Humidity detection element and hygrometer |
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