A rotationally symmetric triangulation sensor with low cost reflective optic

For a growing range of optical measurement task, like gap measurement in automotive industry, traditional triangulation sensors have several disadvantages due to the fact that the measurement result is dependent on the orientation of the sensor because of the non rotational symmetry of the optics. Consequently a design method was proposed in (P. Ott, 2003) for a new class of rotationally symmetric triangulation sensors. Such designs can be realized with aspheric reflection optics and area detectors, such as CCD or CMOS. The optics of the sensor can be extended by an imaging optics which allows at the same time image capturing and distance measurement. In this paper we show measurement results of the first mock-up. This system is based on an optical system of one part manufactured by commercially available diamond turning. The layout of the optical system for distance measurement consists of two reflecting aspheric surfaces. We also present approaches and first results on the algorithm for highly accurate evaluation of the captured data.