Optical flat

The flat glass (or plan sample glass or Plane-parallel test tube ) is a manual measuring instruments for testing low flatness deviations lapped or polished surfaces, based on the interference of light.

Plane and spherical curved sample lenses are specified in DIN 58161 Part 1 and Part 2

The measuring faces of micrometers can be tested with test tubes plan parallels for flatness and parallelism.

• Glass product