Want to learn about scatterometers?
This is a great place to start.
There are two classes of instruments for measuring surface roughness: mechanical and optical. Each has its advantages and disadvantages, which we’ll discuss further. But what will ultimately control your choice is whether or not you can contact the surface you need to measure with a stylus. Mechanical instruments measure by dragging a sharp stylus across the surface, which could have some obvious drawbacks.
If you can’t touch the surface, you do have other options: non-contact profilometers use various methods to detect surface roughness without coming into contact with the surface itself. This sounds like the perfect solution, but they do tend to be very expensive. You can read a more detailed explanation of the issue, as well as get some reccommendations for trustworthy companies who make profilometers, here.
Rough surfaces scatter light. In most circumstances, this is bad, so you’ll probably need a way to to controll the amount of scatter by limiting the surface roughness. The relationship between optical scattering and surface roughness, when explained, can give you a better understanding of this issue. Visit our page to learn more.
If you’re using a Mitutoyo SJ-210 to test surface roughness, you may benefit from our guide on setting it up. We’ve put together a list of extra parts you’ll need to hold the instrument while you make measurements, as well as a step-by-step guide on using them. Go to our page to read the full article.
Optical scattering is caused by two mechanisms: surface scattering and volume scattering. The difference between the two is in the name. Surface scattering comes from the interaction between light and the surface of the optical element, and volume scattering occurs in the bulk of the optical material. Head to our page on optical scattering for a more detailed explanation.
You may need to be able to specify the precise amount of surface roughness that’s present on your optical componant. For more information on the length of measurement, interpreting ANSI/ASME B46.1 standard equations, and appropriate ISO standards, visit our page on specifying surface roughness.
There are several different kinds of scattometers that you could use to measure optical scattering. In this article we’ll focus on scanning scattometers, imaging spheres, and conoscopic scatterometers. To learn more, visit our page.
We don’t like leaving anything to chance, so we use several instruments to directly measure and infer optical measurements. Learn about our tools here.
Your first stop, if you haven’t been there already, should be our page on how conoscopic lenses work. Once you understand conoscopic lenses, you’ll notice that our diagrams of conoscopic lenses and conoscopic scatterometers have few differences. Read about those differences here.