MPR: innovative 3D free-form optics profilometer

This paper presents the huge advance in metrology represented by a new free-form profilometer, the Profilometer/Rotondimeter (MPR-700). The MPR-700 is a 3D metrological machine capable to measure quasicylindrical and free-form normal incidence optics maintaining the 2D measuring error below 40 nm at 2σ up to a length of 700 mm. The key to success of MPR is its innovative detection system design that boasts remarkable advantages in the positioning error reduction and to the instantaneous subtraction of the dynamical error. These characteristics make the MPR extremely precise and accurate, insomuch that measurements can be acquired in flight at high speed maintaining the measuring performances. The main advantage of the MPR design is the capability to couple the measuring quality offered by one-dimensional profilometer to the opportunity to the three-dimensional motion of a 3D machines. Here we present the MPR design and the results obtained on single profiles measurements and 3D shape reconstruction for optics of different geometry.