Active vibration isolation device and its control method

• Main Author: Wakui, Shinji
• Format: Patent
• Language: English
• Published: 30.04.2002

The present invention relates to an active anti-vibration device used in a semiconductor exposure apparatus or liquid crystal substrate manufacturing apparatus for transferring and printing a circuit pattern on a reticle onto a semiconductor wafer, an electron microscope, or the like and, more particularly, to an anti-vibration device using a displacement generation element represented by a piezoelectric element or like, i.e., a displacement generation actuator active vibration isolation device comprising a versatile feedback process encompassing the prior art. A hybrid active vibration isolation device has an intermediate plate inserted between a vibration damping subject and a setting surface on which the vibration damping subject is set, and laminated rubber and electromagnetic motors are interposed between the vibration damping subject and intermediate plate. A piezoelectric element is interposed between the intermediate plate and setting surface. In order to detect vibrations of the vibration damping subject, intermediate plate, and setting surface, velocity sensors are provided to them. The active vibration isolation device has a feedback mechanism for controlling the electromagnetic motors on the basis of signals from the velocity sensors provided to the vibration damping subject and setting surface, and controlling the piezoelectric element on the basis of a signal from the velocity sensor set on the intermediate plate.