| 摘要 |
PURPOSE:To detect the minute pressure change at low frequencies excellently and for a wide field of observation, by obtaining the pressure change as temperature change, and providing a pyroelectric element which generates an output. CONSTITUTION:For example, the detecting device is arranged in a closed room. When windows or doors are opened in this state, the atmospheric pressure in the room is changed. Said change in the atmospheric pressure is transmitted to an air chamber through an opening part 191 of a housing 19 of the pressure change detecting device. Since the volume of the air chamber is constant, the pressure change in the air chamber is related to the temperature change. The temperature change at this time is absorbed by a heat absorbing film 121 and transduced into an electric signal through the pyroelectric element 12. Said electric signal passes as FET16 and is outputted from pins 171-173 as detected pressure change signals. In this way, by obtaining the low frequency pressure change as the temperature change, the minute pressure change at the low frequency of 10Hz or less can be excellently detected over the wide field of observation. |
