|Reference algorithms and metrology on aspherical
and freeform lenses
|Period:||Jun 01, 2016 - May 31, 2019|
|Recipient -- coordinator:||Institute of Plasma Physics, Czech Academy of Sciences, Prague -- Ing. Vít Lédl, Ph.D.|
|Co-recepient(s) / PI(s):|
Aims of the project: : Aspherical optics are a subset of freeform optics with complex geometry i.e. a composition of two geometries such as, for example, a conic and a polynomial part, that nevertheless that can have a revolute invariance degree. Unlike simple shapes and rotationally symmetric aspheres, freeform surfaces are non-rotationally symmetric and can therefore be of any shape. They are characterized by having no invariance degree. Thus, aspheres and freeform surfaces are a class of optical elements with diverse and growing applications in imaging systems (medical, safety, automotive, energy and defence applications), astronomy, lithography, synchrotron techniques, etc. Their use has grown considerably in the last few years because aspheres and freeforms have more degrees of freedom than classical spherical optics. Optical systems that use aspheres (e.g. camera, satellite, medical devices, vision systems, smartphone, synchrotron, etc.) have fewer optical elements (leading to less loss of light, less production costs, less weight, etc.) and higher imaging quality.
High quality applications require high quality aspheres and freeforms, which is why commercial optical aspheres are usually manufactured by modern polishing techniques for optics. Nonetheless, high quality optical surfaces can be realized only if the metrology for aspheres and freeform, and the traceability to the SI unit meter are well established which is very challenging because of the high dynamic range of the information.
The strength of European production in optics is not the mass market, but high quality optical systems, e.g. with a superior imaging quality, better than /10, where is the wavelength of light. This means that the surface quality of the optical elements used must be better than 50 nm, and the metrology has to be much more accurate.