| 摘要 |
A preferred position detection system for accurate one-dimensional operation is realized using a diffractive encoder which provides two digital output signals 90 movementbetween two objects. The diffractive encoder includes: a light source; a collimating lens; a mask; a diffractive grid; four photodetectors; and two comparators. Light from the light source is collimated through the collimating lens, selectively passed through the aperture in the mask, diffracted by the diffractive grid, sensed by the four photodetectors, then compared by the comparators to produce the two digital output signals which represent relative movement between the mask and the diffractive grid.
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