Patent ID: 6339336
Filing Date: 2002-01-15
Classification: B23K,G01D

Abstract:
A moving magnet type galvanometer comprising:a case; a stator having a ferromagnetic outer yoke held in the case and a coil fixed inside the outer yoke; a rotor having a cylindrical permanent magnet and a front shaft and a rear shaft supporting the permanent magnet; an inner race and an outer race of a rear bearing, into which the rotor inside the coil is inserted and which supports the rear shaft, said inner race and said outer race of the rear bearing being fixed to a periphery of the rear shaft and the case, respectively, and an inner race of a front bearing supporting the front shaft, said inner race of the front bearing being fixed to a periphery of the front shaft, and an outer race of the front bearing, said outer race of the front bearing being movable in an axial direction by applying force in the rear shaft direction with springs; a butterfly-shaped common electrode prepared by patterning a conductive thin film on a surface of a glass disc, the butterfly-shaped common electrode having a flat portion; a hub having a flat disc portion and a hub portion, mounted on an end of the rear shaft through a hole provided in the center of the hub portion and holding the butterfly-shaped common electrode with the flat portion perpendicular to the shaft; a spacer; and a four-division electrode mounted on the spacer so as to oppose the common electrode with an air gap therebetween, wherein the spacer is mounted on the case and the air gap is less than 0.1 mm wide.