Centre for Sensors, Instruments and Systems Development

Universitat Politècnica de Catalunya

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Miguel Ares receives the Outstanding PhD Award

CD6 researcher Miguel Ares has been distinguished with the Outstanding PhD Award, granted by the UPC. The thesis entitled "Complex Wavefront Reconstruction and Active Compensation Techniques" was directed by Santiago Royo and has been developed in the framework of the projects "High speed sensorless adaptive optics for the development of new metrological applications" and "Development of new metrological applications on micro and nanometrical scale based on adaptive optics techniques", both funded by the National Programme for R+D+i.


The continuous improvements of optical design tools and manufacturing technologies of free-form optical elements, allow the creation of new complex-shaped lenses that improve the performance of traditional optical systems and make possible new optical applications. The quality of fabrication of complex-shaped lenses depends on the possibility of measurement of the shape along the manufacturing process. Moreover, the measurement of the shape of fabricated lenses is a usual quality control process conducted by the manufacturing industry to ensure the quality of commercial lenses. The measurement of complex-shaped optical surfaces has been usually done with mechanical contact stylus, to get higher resolutions within the larger dynamic range required. However, stylus devices have important drawbacks as a slow measurement speed due to make a point by point measurement, and specially the risk of damage of extremely polished surfaces of the lenses due to the drag of the stylus across them. As opposed to those mechanical contact devices of measurement, there are several non destructive optical techniques like interferometry and deflectometry based on the Shack-Hartmann sensor of spherical microlenses, which are much faster due to make a full-field measurement in a single shot. Despite this advantage, these two techniques have a more limited dynamic range of measurement than stylus devices, which does not allow to measure most complex-shaped lenses. Therefore, solutions to extend the dynamic range of those full-field optical techniques are needed. Otherwise, once an optical element has been tested, it is required to finally reconstruct its shape from the discrete data obtained in the measurement. In the lenses’ field, the modal Zernike representation is commonly used to reconstruct the shape. However, to describe complex shapes with steep local changes, zonal representations fit better. Among them, it must be mentioned the B-Spline representation, which is used by the ophthalmic lenses’ manufacturers in the design and modelling of complex progressive surfaces of lenses of this type. The current thesis describes various optical solutions to measure and represent the shape of commercial complex-shaped lenses, particularly applied to progressive addition lenses personalized to the user.
CD6 Centre for Sensors, Instruments and Systems Development
Rambla de Sant Nebridi, 10  ·  08222  ·  Terrassa (Barcelona)