Highly precise and flexible measurement of different aspheres and freeforms

New measuring method for checking aspheres within
seconds: MarOpto TWI 60 from Mahr.


With the product group MarOpto, Mahr offers the optical industry measuring solutions for the quality assurance of aspheres and freeforms in all steps of production – from the blank to the polished and coated lens. The Tilted Wave Interferometer MarOpto TWI 60: The innovative high-end interferometer automatically tests the complete surface of polished aspheres with a non-contact method, within seconds without stitching or CGH.


Aspheric and freeform optics must be tested continuously during production for shape deviations. All production steps must be measured – from pre-grinding and fine grinding through polishing to ion beam processing. Non-contact, optical measuring methods are becoming more and more important and set new standards for accuracy and efficiency.

New measuring method: Tilted Wave Interferometer MarOpto TWI 60

With this innovative measuring system, Mahr offers the industry a whole new range of manufacturing-related quality assurance systems for optics: the Tilted Wave Interferometer MarOpto TWI 60 checks aspheres automatically and quickly. The test tower also measures very steep aspheres over the entire surface and also detects medium and high-frequency faults on the test surfaces. Algorithms allow the measurement process to be flexibly adapted to different surface shapes without the need for other accessories such as computer-generated holograms (CGH). In this case, stitching is not necessary during the surface inspection of an asphere. Mahr was awarded the AMA Innovations Prize by the Association for Sensor Technology and Measurement Technology (AMA) and was nominated for the PRISM Awards 2015 of the SPIE (International Society for Optics and Photonics) and Photonics Media in the category "Other Metrology Instrumentation".

Innovative: Combination of optical and tactile measuring sensors

The combination of optical and tactile measuring methods combined with automated measurement sequences is offered by another innovative measuring station from Mahr: The optical-tactile measuring station MarForm MFU 200 Aspheric 3D calculates the 3D topography as well as centering and tilting errors of aspheres, freeforms and special optics. The highly accurate measuring instrument realizes several measurement tasks in one clamping: it measures the form and contour of lenses and simultaneously checks them for axis misalignment, runout and tilting errors. The test pieces are positioned, tilted, centered and aligned independently of the operator. Active tracking even enables 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. With automation, users can significantly increase the productivity of their quality assurance.


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