Title:
VACUUM GAUGE
Document Type and Number:
Japanese Patent JPS63113332
Kind Code:
A
Abstract:
PURPOSE:To measure an atmospheric pressure accurately, by measuring the atmospheric pressure depending on changes in the drag of gas molecules acting on a planar vibrator to prevent any aging in the detection value. CONSTITUTION:When a vibration voltage is applied with a vibrating circuit 7, a planar vibrator 2 vibrates. Here, the electrostatic capacitance changes between the vibrator 2 and a displacement detection electrode 6 and hence, the displacement of the vibrator 2 can be detected by checking changes in the electrostatic capacitance with a displacement phase output circuit 8. A phase difference detection circuit 9 detects a phase lag in the displacement of the vibrator 2 as a detected with the displacement detection circuit 8 with respect to the applied voltage of the vibration circuit 7. The phase lag maintains a one-to-one correspondence with an atmospheric pressure.
Inventors:
TERASAWA TSUNEO
SATO KAZUO
KAWAMURA YOSHIO
TANAKA SHINJI
SATO KAZUO
KAWAMURA YOSHIO
TANAKA SHINJI
Application Number:
JP25821786A
Publication Date:
May 18, 1988
Filing Date:
October 31, 1986
Export Citation:
Assignee:
HITACHI LTD
International Classes:
G01L9/00; G01L21/00; (IPC1-7): G01L9/00; G01L21/00
Attorney, Agent or Firm:
Katsuo Ogawa