OPTICAL IMAGE STABILIZER

摘要

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.

主权项

1. An optical image stabilizer for a telescopic optical instrument having a telescopic optical system made up of an objective lens, an erect prism and an eyepiece lens arranged in this order and mounted on a telescope housing, the erect prism being capable of rotating on first and second axes of rotation intersecting an optical axis of the telescopic optical system at a common point at right angles so as to compensate for deteriorations of a telescopic optical image caused due to external vibrations, the optical image stabilizer comprising:
gimbal means for mounting thereon the erect prism, said gimbal means comprising:
a gimbal casing fixedly mounted on the telescope housing:an external gimbal frame rotatably mounted on the gimbal casing so as to rotate on the first axis of rotation; andan internal gimbal frame rotatably mounted on said external gimbal frame so as to rotate on the second axis of rotation, the erect prism being fixedly mounted on said internal gimbal frame; a pair of voice coil motors for rotating said external gimbal frame and said internal gimbal frame on the first and said second axes of rotation, respectively, each said voice coil motor comprising first yoke means which has a permanent magnet and second yoke means which has a loop-shaped coil with an empty space therein, and a position detector element disposed in the empty space for providing a position signal indicating a position of said coil relative to said permanent magnet; and a circuit board fixedly mounted on said external gimbal frame, said circuit board being provided thereon with a driver circuit for actuating each said voice coil motor; wherein said second yoke means of each said voice coil motor is mounted on said circuit board, said first yoke means of said voice coil motor for said external gimbal frame is mounted on said gimbal casing oppositely to said second yoke means of said voice coil motor for said external gimbal frame, and said first yoke means of said voice coil motor for said internal gimbal frame is mounted on said internal gimbal frame oppositely to said second yoke means of said voice coil motor for said internal gimbal frame.