PURPOSE: To measure the absolute value of pressure without a temperature sensor and a temperature correcting sensor and without the effect of temperature change.
CONSTITUTION: One surface of a signal-crystal silicon substrate is etched, and a pressure sensitive part comprising a thin part 5 and a thick part 6 is formed. A recess part 7 is formed in the other surface, and a diaphragm 1 is formed. An upper glass plate 2 is attached on the diaphragm. The upper glass plate 2 has an electrode 8 facing the pressure sensitive part and a ventilating hole 9 communicating with a space formed between the electrode 8 and the pressure sensitive part. A pressure buffer member 4 is attached above the hole. The pressure buffer member 4 comprises a flexible film 10 and a frame-shaped supporting body 11 for supporting the surrounding part of the flexible film 10. A tightly sealed space 12 is formed between the film and the diaphragm 1. A stage glass plate 3 having a ventilating hole 13 is attached beneath the diaphragm 1. The flexible film 10 of the pressure buffer member 4 is bent in responce to the change in ambient temperature, and the pressure P0 in the tightly sealed space 12 is kept constant.
UEMATSU SHIYOUICHI
ESASHI MASAKI
