| 摘要 |
<p>The invention provides a device for the shifting of the phase of a projected grating (26) by the use of a plurality of transparent plates (28A, 28B), each disposed at a different angle with respect to the angle of the grating (26), which plates (28A, 28B) may be selectively placed between the grating (26) and the projecting lens (30) of a projecting system to modulate, that is to shift, the phase of the projection of the grating (26) on a test surface.</p> |
