Nutating radiation deflecting method and apparatus

Abstract

There are disclosed radiation deflection method and means for controlling the direction of travel of radiation which is subject to refraction, such as light and sound radiation. The deflection method and means, which are particularly adapted for effecting a scanning motion of the radiation in one direction, include first and second generally counterrotating refracting wedges through which the radiation passes. The second wedge is mounted for rotation about a fixed axis and the first wedge is mounted for rotation about an axis which nutates about the fixed axis of rotation of the second wedge. Means are provided for rotating the first and second wedges in opposite rotary directions at equal angular displacements while simultaneously nutating said first wedge. For use with acoustic radiation a fluid filler medium is provided between the wedges, and a linear array of transducer elements is included over which the scanned compressional acoustic image field is swept by operation of the deflection system for converting the image field to an equivalent electrical signal. Novel wedge mounting and drive means are disclosed for the simultaneous rotation of the first wedge and nutational movement of the rotational axis thereof in the above described manner. The sum of the absolute amount of refraction of the radiation at the various interfaces of the system in passing through the system is minimized to substantially reduce mode conversion and aberration thereat.