Sensor element

Abstract

PURPOSE:To obtain a small-sized, low-cost sensor by covering a sending film for reference with a shield body without using a can package for hermetic sealing. CONSTITUTION:An SiO2 film 2 on an Si substrate is etched anisotropically to form a couple of through grooves and a bridge 3 is provided between the grooves. The sensing film 4 made of a thin film thermistor material is provided on the bridge 3 and a couple of inter-digital electrodes for impedance detection are provided on the film 4. Two bridges 3 are provided successively on the substrate and the same sensing film 5 is mounted on the other bridge 3. The sensing film 4 is exposed to the external field and varies in impedance with temperature. The shield body 6 provided with a cubic Si block recessed part is adhered on the substrate 1 mounted on the sensing film 5 and sealed airtightly so that it is not affected by the humidity of the external field. Both sensing films 4 and 5 vary similarly with atmospheric temperature, so temperature compensation is performed and the humidity of the external field is accurately detected from the output difference between the outputs of both films 4 and 5.

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Cited By (5)

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    JP-2006343106-ADecember 21, 2006Honda Motor Co Ltd, 本田技研工業株式会社Gas sensor
    JP-4575846-B2November 04, 2010本田技研工業株式会社ガスセンサ
    JP-H02179459-AJuly 12, 1990Sharp CorpStructure of moisture sensitive element and humidity sensor
    JP-H05288705-ANovember 02, 1993Sharp Corp, シャープ株式会社センサー素子
    US-5048336-ASeptember 17, 1991Sharp Kabushiki KaishaMoisture-sensitive device