The autocollimator combines both optical tools, the collimator and the telescope into one instrument using a single objective lens. Both beam paths are seperated by using a beamsplitter. The autocollimator is a very sensitive angle measuring device and is thus used for the precise angular adjustment of optical or machine components. Due to the collimated beam (infinity adjustment) the measurement results are independent from the distance to the object under test. The operating principle is explained in the following.
Fig. 1 Schematic cross section of an autocollimator
Fig. 1 shows a schematic cross section of an autocollimator. The collimator components, i.e. light source and collimator reticle, are arranged vertically, while the telescope components, i.e. eyepiece reticle and eyepiece, are arranged horizontally along the mechanical axis of the lens tube. The optical paths are combined via a beam splitter and share the same objective lens.