Abstract: An image stabilizer applicable to a monocular or binocular optical system. The stabilizer includes an erecting prism placed between an objective lens and an eyepiece to compensate for deterioration in a quality of an observed image caused by hands movement. The image stabilizer includes a gimbal suspension system having pivot shafts respectively extending to left and right sides of the optical axis of the optical system. The pivot shafts have a common pivot axis perpendicular to the optical axis. The gimbal suspension system has an erecting-prism holder supported by the pivot shafts, an angular velocity detector for detecting an angular displacement of the erecting prism, and a voice coil motor for pivoting the erecting-prism holder.

Abstract: An optical image stabilizer for a telescopic instrument having an objective lens, an erect prism, and an eyepiece lens arranged in this order which is capable of compensating for image deteriorations of an observed image due to external vibrations. The optical image stabilizer has a gimbal device mounted on a telescope housing, an external gimbal frame rotatably mounted on the gimbal casing, and an internal gimbal frame with the erect prism fixed thereto. Voice coil motors are provided for rotating the external and the internal gimbal frames. One of the voice coil motors has a coil disposed on the circuit board and a permanent magnet disposed on either one of the external and the internal gimbal frames oppositely to the coil. The remaining voice coil motor has a coil disposed on the circuit board and a permanent magnet disposed on the other gimbal frame oppositely to the coil.