Essilor International

Patrick Bertrand

Gilles Le Saux

Xavier Lippens

Werner Mohr

Do Quyen Phan

Christophe Lafay

A fringe deflectometry apparatus illuminates an optical component to be measured using radiation with a known wavefront, deflects the radiation after it has been reflected or transmitted by the optical component to be measured, and materializes a reference ray. Transverse aberration of the reference ray after reflection or transmission by the optical component is measured. A deflectometry method using the apparatus enables an absolute phase reference to be provided.

Fringe deflectometry apparatus and method

A method and device for measurement of the geometrical or optical structure of an optical component such as a lens or a mold for making lens are provided. The method comprises the steps of illuminating the optical component to be measured with incident light having a known wavefront, measuring, in a given plane, the maps of the wavefront slopes of the light, after reflection at or transmission by the optical component, and deducing the surface topography or refraction index map of the optical component to be measured from the measurements of the slope maps by the application of at least one calculating procedure. The calculating procedure comprises a step in which a result surface is initialized using a simple starting surface SD' and at least one optimization step; each optimization step involves calculation of the value of a merit function representative of the departure between the result surface and the surface to be measured of the optical component and, minimization of said value varying said result surface, said variation being expressed in the form of at least one intermediate surface S.sub.i.

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Issy-les-Moulineaux, France

Patrick Bertrand