The analysis of the form of aspheric lens surfaces

Recent developments in high precision machining have allowed for the design and manufacture of precision aspheric lenses. These have the advantage over conventional spherical lenses in that a multiple element lens can be replaced by a single aspheric lens. There are however difficulties both in the measurement of the lens surface after machining and the assessment of the quality of the lens. In this paper an aspheric lens surface is measured using a 3D Form Talysurf. The data are then analysed using an analytical least-squares technique to fit the points to an exponential function. The methods developed show that the machining methods can now be complemented by an analysis technique