In-Situ Surface Inspection Using White Light Channelled Spectrum Interferometer

We introduce a new environmentally robust optical interferometry system
for fast surface profile measurement. The proposed white light channelled spectrum
Interferometer (WLCSI) is effective for applications in on-line surface inspection
because it can obtain a surface profile in a single shot. Compared to the traditional
spectral interferometry techniques, cylindrical lens is used in the Michelson
interferometric objective of our system to achieve the measurement of long profiles.
Combined with a modern high speed CCD camera, general-purpose graphics
processing unit (GPGPU) and multi-core processors computing technology, large
dynamic measurement with a high signal-to-noise ratio is realized. The designed
prototype of WLCSI is presented and its performance was evaluated experimentally
by measuring two surface samples. The measuring results closely align with the
calibrated specifications given by the manufacturer as well as the measurement results
by the other commercial instrument, which shows that the proposed WLCSI could be
applied to production line like the roll-to-toll (R2R) surface inspection where only
defects on the film surface are concerned in terms of the quality control