| 摘要 |
A novel linear motor making use of a D.C. current and a precise positioning device employing the linear motor and adapted to be used in a semiconductor manufacturing apparatus, are described herein, in which magnetic fields having alternately reversing directions of magnetic paths are formed at equal intervals along a straight line, one set of two coils is placed in this magnetic field as positioned in such manner that when one of the coils crosses the lines of magnetic force to a maximum extent, the other coil may cross the lines of magnetic force to a minimum extent, there coils are mounted on a loading table, conventional feedback is effected from a detector for detecting the position of the loading table via an F-V converter, two memory devices respectively connected to current amplifiers having variable amplification factors are in turn connected to a counter connected to the detector, the current amplifiers are respectively connected to said coils so that an amplified current having a controlled polarity may be passed through the coil crossing more lines of magnetic force according to a program preliminarily set in the memory devices, whereby said one set of coils can be applied with any arbitrary driving force in a fixed direction throughout the entire magnetic field.
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