| 摘要 |
PURPOSE:To obtain an encoder wherefrom an output of high resolution can be obtained, by providing a rotary disk in which position information is written in a magnetic substance at prescribed intervals and which is driven to move by a driving device, and a plurality of magnetic heads which are disposed in positions opposite to the position information recording positions of said disk at an interval being in a prescribed ratio to the width of writing of the position information. CONSTITUTION:A magnetic head member 10 is constructed of a plurality of magnetic heads which are formed of writable/readable M/R elements. On the other hand, position information is written at prescribed intervals on the outer peripheral surface of a rotary disk 20 which is coated with a magnetic material having a high holding force. Moreover, the magnetic head member 10 is so disposed as to have a prescribed gap to an opposite position on the outer peripheral surface of the disk 20. The ratio between the width l1 of a writing period of the position information and the interval l2 of disposition of the magnetic heads is set to be l1:l2=10:9, for instance. When the position information recorded on the disk 20 are read by one magnetic head in this arrangement, an output ten times as precise as one delivered as it is can be obtained by a so-called vernier scale effect.
|
