| 摘要 |
An optical positioning device using astigmatic optical elements. A laser diode emits astigmatic, elliptically shaped light which is not corrected. A first lens condenses the light and transmits the light to an object to be positioned. The light reflected off of the object is monitored while the object is moved. Because of astigmatism, the first lens does not have a true focal point. There is a point, however, where the vertical and horizontal components of the transmitted light are equal. The first lens is positioned so that the desired position of the object corresponds to this equal point.
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