Patents Assigned to Hydrolab AB
  • Patent number: 4935841
    Abstract: A capacity pressure sensor having a housing and a diaphragm. The housing and the diaphragm are substantially flat and are connected to each other at an upstanding border at the periphery of the housing. In the hermetically closed space between the housing and said diaphragm a reference pressure is applied. In a pressure measurement the diaphragm is bent inwards relative to said housing depending on the pressure acting on the surface of said diaphragm. This bending inwards is a primary output signal which capacitively can be converted to an electrical signal. Inside the pressure sensor on the inner surfaces of said housing and said diaphragm there are arranged, for the detection of the position of said diaphragm relative to said housing, capacitor plates connected to an electrical measuring circuit for detection of the capacity of the capacitor formed thereby. To enhance the linearity of the measuring capacitor the outer flat surfaces of the pressure sensor are coated with conducting layers connected to earth.
    Type: Grant
    Filed: October 4, 1989
    Date of Patent: June 19, 1990
    Assignees: Johnsson & Billquist Development AB, Hydrolab AB
    Inventors: Staffan Jonsson, Ray Olsson