Reference formtester for aspheres and freeforms

Testing of aspheres and freeforms
With the MarForm MFU 200 Aspheric 3D from Mahr, optics manufacturers of aspheres and freeforms can test

• three-dimensionally
• quickly and
• production-oriented

Several measuring tasks in one clamping
The highly accurate measuring instrument with a very small measurement uncertainty realizes several measuring tasks in one clamping: it measures

• form
• contour

of lenses and simultaneously tests their

• axial offset
• run-out error and
• tilting error

Operator-independent positioning
The test specimens are positioned, tilted, centered and aligned independently of the operator. Active tracking even allows the measurement of freeform shapes and aspheres with unknown geometry. Polished lenses are detected without contact and without damage with the optical fiber probe. The tactile probe arms are suitable for rough surfaces.

Optical and tactile measurements
The optical measurement is carried out via an interferometric point sensor. For tactile measurements, there is a wide range of sensing arms. The optical as well as the tactile sensor are positioned in any desired angular position via a motorized rotary joint and are thus very flexible. The probe system T7W offers the possibility to hold several probes in combination optic/tactile.

Accurate and reproducible measurements of aspheres
The exact alignment of the highly accurate axis of rotation with a roundness deviation of approx. 20 nm allows an accurate and reproducible measurement of aspheres. For a precise measurement of the 3D topography, the zenith of the optics is measured and reoriented before the measurement. As a result, even the smallest errors which occur as a result of clamping are compensated for. The dynamic real-time compensation enables the high accuracy of the machine and prevents interference by external influences.

Measuring booth allows damping
The MarForm MFU 200 Aspheric 3D is a further development of the reference formtester MarForm MFU 100 – a highly accurate form measuring machine that is successfully used worldwide. Significant innovations have been implemented for the production-oriented measurement in the optical industry:

• A measuring booth enables damping and leveling control
• The real-time compensation of all machine errors takes place via reference rulings in all three main measuring axes and thus also corrects the smallest deviations in the measuring sequence
• Due to the high temperature stability, the daily calibration is not necessary

The suitable software
With the proven software platform MarWin and the measuring and evaluation package "Aspheric", the measurement results of aspheres, diffractive optics (DOE) and freeform models can be evaluated.

More information on the measuring system MarForm MFU 200 Aspheric 3D can be found here...