| 摘要 |
<p>In an optical apparatus, particularly magnifying apparatus such as microscopes or screen projectors, a magnified image of an object is produced on a focal plane, in which focal plane is rotated a planar device on two parallel surfaces of which device are provided respective arrays of parallel grooves such that the cross-section through each surface and transverse to the groove length is in the form of a plurality of arcs, The grooves in one surface are arranged transversely to the grooves in the other surface. A field lens system is arranged to receive light from the said device. The effect is to provide an enlarged pupil both when the device is at rest and when it is rotating.</p> |
