| 摘要 |
<p>The flatness of at least a portion of a substantially planar surface (16) is measured by illuminating the surface through a beam splitter (12) incorporating a grid (13) or other patterned shield. The light pattern reflected from the surface (16) is directed by way of a reflector (14) back through the beam splitter (12) and thus through the grid (13). The image exiting the beam splitter (12) has characteristics representative of the flatness of the surface.</p> |
