| The light waves emitted from a monochromatic light source
are subject to beam splitting at the interfaces between test glass (an optical flat) and
test specimen. After travelling variously long optical paths, the fractional waves reunite
but produce interference (overlapping of waves) as they do so. This interference can be
observed as bright spots or stripes (interference maxima) and dark spots or stripes
(interference minima). The bright and dark stripes are called light bands (optical process
for testing the flatness of sliding faces). |
|
Optical flatness control according to the interference
method 
|
