Actuator using bi-directional electrostatic force

An actuator using a bi-directional electrostatic force, comprising:

• an upper electrostatic force generator configured to generate a first electrostatic force in response to a first high voltage signal,
• a lower electrostatic force generator configured to generate a second electrostatic force in response to a second high voltage signal having a phase difference with the first high voltage signal, and
• a vibration generator positioned in a space between the upper electrostatic force generator and the lower electrostatic force generator and configured to generate vibration in response to the first and second electrostatic forces,
• wherein the first high voltage signal and the second high voltage signal have a phase difference of 180 degrees,
• wherein:
• the first high voltage signal is applied to the upper electrostatic force generator during a first half cycle, and
• the second high voltage signal is alternately applied to the lower electrostatic force generator during a second half cycle in which the first high voltage signal is not applied,
• wherein each of the first high voltage signal and the second high voltage signal has a positive value, and
• further comprising:
• a high voltage generator configured to generate and supply a present DC high voltage,
• a controller configured to generate first and second high voltage control signals so that the first and second high voltage signals are generated, respectively,
• an upper electrode high-voltage signal generator configured to generate the first high voltage signal having the positive value in response to the first high voltage control signal and to supply the first high voltage signal to the upper electrostatic force generator, and
• a lower electrode high-voltage signal generator configured to generate the second high voltage signal having the positive value in response to the second high voltage control signal and to supply the second high voltage signal to the lower electrostatic force generator.