Rens Henselmans

Measuring optics with nanometre accuracy – from prototype to product

12:00 – 12:30

From 2003-2009 TNO, TU Eindhoven and VSL developed the Nanomefos measurement machine in a Senternovem IOP Precisie Technologie project. This nanometre accuracy non-contact measurement machine for aspherical and freeform optics has proven itself in production of world-class aspherical and freeform optics at TNO over the last decade. Although frequent interest was shown for a copy of the machine, it has remained the only one of its kind until now. Over the last year, Dutch United Instruments (part of Demcon) has redesigned the prototype and is now providing the first machines to optics manufacturing companies worldwide.

Aspherical and freeform optics offer great advantages over conventional spherical optics, as they can improve performance, reduce size and weight, and offer much more design freedom. Application is becoming more and more common, and can nowadays be found in space instruments, head-up-displays, lighting, VR headsets etc. Manufacturing equipment such as deterministic polishing and slow-tool-servo diamond turning has become widely available now. Also, some metrology equipment has become commercially available. However, the flexibility, size and measurement accuracy that the Nanomefos concept offers is still unique and nowadays provides a viable business opportunity.

As the optics production market is segmented mainly by diameter, the re-design was aimed at creating a modular, scaleable platform. For the PhD prototype, the motto was: ‘let’s do it as good as we can, maybe that will be good enough.’ Some features have proven to work better than expected, giving space for cost reduction and improving robustness and serviceability. Also, a roadmap for additional features was made for which space has been reserved in the platform design. The first machines will be delivered to customers this year, and development of new models and functionalities will result in a Dutch made family of NMF machines, 17 years after a graduate student drew up the first lines on a blank piece of paper.

Rens Henselmans studied mechanical engineering at TU Eindhoven, and graduated on the concept design of a measurement machine for freeform optics in 2003. This development was continued in a PhD project, resulting in a working prototype machine in 2009. He then moved to TNO, together with the machine, and worked there as a system architect on various space and astronomy instruments, while also continuing work on the machine. From 2013 to 2017 he worked as system architect at NTS-Group on semicon and medical projects, from prototype to series production ready products. In 2018 he joined DUI as CTO for the development and commercialization of the NMF measurement machine, which is based on his graduation concept.

Rens Henselmans

Dutch United Instruments