Abstract: An electrostatic field sensor is shown by using a vibrating micro-spring supported membrane as the sensing element. The sensing mechanism involves electrostatic force to deflect the membrane, and a photoelectric sensor to measure membrane movement based on the laser reflected amplification method. A bias voltage applied to the membrane can be used to increase measurement sensitivity. Electrostatic field is detected by measuring the deflection of equilibrium position of the membrane. It is presented for the measurement of de electric field. Measure- ment error is about 3% for a 1V/mm de weak electrostatic field. The application of this sensor is for weak electric field monitoring.

Key words: micro-spring, vibrating membrane, electrostatic field sensor