OptiFLAT III is an equal path interferometer which compensates for white light, producing a narrow plane of fringe localization from a test surface 150mm outside of the interferometer. The OptiFLAT III is designed to measure polished flat surfaces’ 3D topography, and enhance the sensitivity, reliability, and resolution of our customers’ surface measurements to meet advanced requirements.

OptiFLAT’s unique architecture tests surfaces without contact at a significant stand-off from the frame. The large stand-off is ideal for automated handling of parts. The plane of focus — in which interference occurs — is extremely shallow compared to laser interferometers, which have coherence measured in meters, rather than microns. This attribute of the optical system allows testing of transparent substrates that have parallel front and back planes, such as glass hard disks, photomasks and LCD panels, without producing interference from the back and front surfaces simultaneously. Moreover, back- and front-surface topographies can be measured, as well as thickness.

Data acquisition is typically complete in seconds. After phase shifting, OptiFLAT’s automated software calculates height and 3D parameters, including flatness, waviness and root mean squared. Custom applications, such as those for data storage which measure runout, velocity and acceleration, are available for various 3D metrology needs. 3D and 2D profile plotting and analysis helps visualize process-dependent topography, including microwaviness..