Donald K. Cohen Ph.D.

3D optical profiling, developed in the early 1990s, is crucial for high-resolution measurement of optics, semiconductors, medical devices, and precision machining. Recent developments have expanded its capabilities, allowing high-resolution surface texture measurements over many square millimeters in minutes.

Specifications for surface texture frequently focus on surface “roughness”—the finer structures in the texture—often to the exclusion of the “waviness”—the larger structure of the texture. Unfortunately, problems related to sealing, vibration, noise, wear, etc., are regularly caused by issues hidden in the waviness domain, which cannot be captured by common roughness specifications.

How does the surface texture affect the friction between two dry parallel sliding surfaces? It turns out that this problem has challenged some of the greatest minds in science and engineering.