Meaning
Non-contact interferometry methods use the interference patterns of light and shadows to measure the flatness or warpage of a surface.
Grating Projection
Measurement hardware projects a known pattern of lines onto the target through a physical or digital grating. The shadow moiré technique captures the distortion of these lines as they fall across an uneven surface. High resolution cameras record the resulting fringe patterns to calculate precise height variations.
Planarity Tolerance
Engineers use these visual maps to verify that printed circuit boards meet the flatness requirements for high speed assembly. When components are mounted, even a slight curve in the board can cause solder joint failures. Shadow moiré provides a full field view of the surface rather than just a few discrete points.
Thermal Stress
Heating the sample inside a specialized oven allows for the observation of warpage changes during a simulated reflow soldering cycle. Modern equipment tracks how the material bends as temperatures rise from room level to over two hundred degrees Celsius. This real time data shows whether the board will remain flat enough to maintain electrical connections during manufacturing.
Sensors detect the exact point where internal stresses overcome the structural rigidity of the substrate. Such detailed analysis prevents mass production errors in complex electronic assemblies.
