| 摘要 |
PROBLEM TO BE SOLVED: To provide a humidity sensor having an insulating substrate and a humidity sensing layer sufficiently closely stuck thereto, having high accuracy, and having stable performance maintained over a long period. SOLUTION: This humidity sensor is equipped with the insulating substrate made of alumina, etc., a lower electrode made of a noble metal, the humidity sensing layer made of a porous material mainly composed of alumina and compounded with a prescribed amount of titania and tin oxide, and an upper electrode made of a porous material of noble metal. These are layered in order, thus forming the sensor. By joining the upper electrode to the sensing layer and to a part of the insulating substrate, this sensor has excellent durability with the sensing layer sufficiently stuck to the insulating substrate. Preferably, the lower electrode is made of a porous material. More preferably, both the lower and upper electrodes are made of platinum. Further, it is preferable that a heater and a resistance temperature sensor are disposed within the insulating substrate and they are disposed just under the sensing layer within the insulating substrate.
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