US Patent 7880902 Contactless optical probe and device and method making use thereof

The probe comprises a light source (20), means for shaping (24, 25, 21) the beam emitted by said light source and the beam coming from a surface arranged close to a target distance, an optical detector unit (22), comprising a pinhole diaphragm (26) and a photoelectric detector (28), providing a voltage peak (31) when said surface is at said target distance and further comprising a diaphragm (27) with a hole larger than said pinhole and a photoelectric detector (29), providing a voltage greater than that produced by said detection sensor (28), except when said surface is a the target distance. The method uses the probe to measure the thickness of an optical lens.