×

Electrostatic capacitance-type sensor

  • US 5,554,973 A
  • Filed: 06/07/1995
  • Issued: 09/10/1996
  • Est. Priority Date: 06/08/1994
  • Status: Expired due to Fees
First Claim
Patent Images

1. A proximity detector comprising:

  • a pulse generator;

    first and second delay circuits receiving an output of said pulse generator and having first and second capacitances respectively;

    an electrostatic capacitance varying converter connected to at least one of said first and second delay circuits to vary a delay of said at least one delay circuit by varying a respective one of said first and second capacitances;

    said first and second delay circuit each having a constant current circuit, controlled by said pulse generator, for changing a set state of charge on said first and second capacitances, respectively, in a substantially linear manner; and

    a phase discrimination circuit for detecting a phase difference between outputs of said first and second delay circuits.

View all claims
  • 2 Assignments
Timeline View
Assignment View
    ×
    ×