Device for determining the profile of a surface

In a device for determining the profile of a surface comprising:

• a source comprising a light generator providing an optical beam, a controllable deflection element arranged to receive the light emitted from the said generator and a first deflector arranged to receive the light emerging from said deflection element and to reflect back that light according to the beam that forms a light spot on said surface;
• a detector system comprising a lens, a photosensitive element arranged in the focal plane of the lens to generate an output signal when said lens forms the image of said spot on the photosensitive element, the detector system defining a detection axis cutting said beam;
• means for driving the beam and said detection axis in a rotating movement about a common axis of rotation cutting both the beam and the detection axis, wherein the beam and the detection axis remain in a same plane, the source further comprising means to control said deflection element to scan an angular sector of the same plane, the scanning speed being greater than that of the rotation of the beam and the axis of detection;
• means for measuring the angle formed by the beam and the detection axis when said output signal is generated by the said photosensitive element, wherein the improvement comprises:
• a Dove prism arranged on the same axis of rotation between said deflection element and the first reflector and means for driving said Dove prism in a rotating movement;
• the detection system further comprising a second reflector arranged so that the light which propagates along the axis of detection is reflected back towards said lens along said same axis of rotation, said first and second reflectors being mechanically coupled together, their planes being respectively perpendicular to said same plane;
• and
• said means for driving the beam and the axis of detection about the same axis of rotation includes means for making said first and second reflectors rotate about the same axis of rotation at a speed synchronized with that of the Dove prism.