| 摘要 |
A light beam is repeatedly deflected in the longitudinal direction through a holographic element HOE by means of a rotating multi-faceted mirror. This HOE is so formed that the beam entering at different angles leaves the HOE as a telecentric beam. Through a further HOE the telecentric beam is diffracted onto an electro-optic transducer. In the region of the telecentric beam is located an object to be measured, and the time of the interruption of the telecentric beam by means of this object enables the dimension of the latter to be determined. The production of the telecentric beam and the deflection of the latter onto the transducer by means of the HOE allows a simple cost-effect manufacture as well as a simple evalution of the measurements with increased precision. The manufacture of the HOE is likewise simple. |
