Measuring the refractive power with deflectometry in transmission

“Phase-measuring Deflectometry” (PMD) meanwhile is well established for measuring specular surfaces – in reflection [1]. One application is the measurement of the so-called reflection-optics of car glass windows. This is important from an aesthetic point of view only. Now, the question was, if it is also possible to measure the security-relevant refractive power of car glass windows in transmission to provide a second, traceable method in addition to the existing methods [2]. The target accuracy was 1 mD for a distance ∆x of 3 mm (Fig. 1). This corresponds to a wave aberration of 1 nm only.