Disk type of absolute-position magnetic encoder for rotary devices
 A disk type absolute-position magnetic encoder for rotary devices. It includes: (a) a circular magnetic shielding disk; (b) a plurality of permanent circular magnetic rings of varying diameters disposed on both sides of the magnetic shielding disk; (c) a circular neutral zone between every two adjacent circular magnetic rings, the circular neutral zone having a width wide enough such that it is effectively free of magnetic interference; (d) a plurality of sensors each being located at a distance from one of the circular ring for detecting a position of the rotary device; and (e) a spindle transversely running through the magnetic shielding disk. Compared to the prior art devices of optical and drum types, the disk type magnetic encoder provides substantial space savings. The magnetic shielding disk, the plurality of permanent circular magnetic rings, and the sensors are all mounted in a cylindrical housing. 
Industrial Technology Research Institute
G
G01D
inventional
Hukao Fu Huang Shih Chen Shih Tsai Wei
Jen Ming Chou Shin