10-25-2017, 04:02 AM
EOU, you are correct! 
Reading you reply I have realised that for most people both the thinness of the edge apex and the wavelength of blue light are beyond personal experience.
For me, who often plays with laser goniometer for edge angle measurements, it is slightly different. I have been thinking for a quite long time whether it would be possible to build a simple optical device for measuring the edge width. The laser beam could serve as an optical test medium. But so far I have no practical solution.
In the optical industry simple interferometry is often used to test the quality of surfaces.
Reading you reply I have realised that for most people both the thinness of the edge apex and the wavelength of blue light are beyond personal experience.
For me, who often plays with laser goniometer for edge angle measurements, it is slightly different. I have been thinking for a quite long time whether it would be possible to build a simple optical device for measuring the edge width. The laser beam could serve as an optical test medium. But so far I have no practical solution.
In the optical industry simple interferometry is often used to test the quality of surfaces.