PURPOSE: To measure humidity with high precision by using a humidity sensor capable of communicating with outside air as one of two uniform element and sealing the other element as a reference humidity sensor, and detecting the differential output between both sensors.
CONSTITUTION: Elements 1 and 2 having the same characteristics are provided on the same substrate adjacently as the humidity sensor A and reference humidity sensor B. The sensor A is provided with a cap 3 having a window and sealed completely to maintain specific humidity. Electrodes 9W12 are connected to the respective elements 1 and 2. Then, the capacity difference between the humidity sensor A and reference humidity sensor B is detected. Thus, the capacity difference is detected to cancel a capacity value corresponding to a cavity part, so relative humidity is detected accurately from variation in capacity.
SHIMIZU AKIRA
TANABE KYOJI
