Ostrolenk, Faber, Gerb & Soffen
Magnetic recording medium for encoders
 To construct a magnetic recording medium to be used for an encoder adapted for detection of an angular or linear displacement of a mobile object such as a robot arm, a substrate is at least partly covered with a Sm-Co alloy thin layer bearing magnetic information with a magnetization pitch which is at least three times as large as the crystal diameter of the magnetic particles in the alloy. A resultant high coercive force obtained with that alloy allows detection with an enlarged detective distance, and the above-mentioned proper ratio of crystal diameter with respect to the magetization pitch allows detection with low percentage of output variation, thereby enabling easy assembly of the encoder and detection with high precision. 
Yamaha Corporation
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G01D Y10S G11B Y10T
inventional additional inventional additional
Toshiharu Yoshinori Kenzaburo Nobuji Mutsumi
Hoshi Hayashi Iijima Kato Harada