An optical comparator is a precision measurement device that uses the physics behind the properties of light in order to inspect the size and shape of manufactured parts. Similar to a classroom projector, an optical comparator projects a magnified image of a part onto a backdrop screen. A series of very precise lenses and the fixed location of the device help to create an image on the screen that is very accurate and measurable. When using an optical comparator, it is possible to compare the image to measurement units, use screen rotation to measure part angles, or use measurement by motion to measure larger parts. Back to entire glossary
