Development of a simulation algorithm of the surface optical effects on glass plates
Development of a simulation algorithm of the surface optical effects on glass plates


Thomas Grosges
Laboratoire d'Optique appliquée
Université Catholique de Louvain
Chemin du cyclotron , 2
B-1348 Louvain-La-Neuve
Belgium




Abstract




Due to the new exigences of the motor industries for the windshields, in term of the used glass optic qualities, the windshield manufacturers are confronted to new problems and challenges. Indeed, the misreading of the played role by the glass defects, in term of reflection and transmission of the light, and their origins become crucial problems. These optical perturbations, in term of defaults, can be classified in two types. The first one includes the optical effects due to the internal glass defects (or mass effects) and the second one includes the surface effects. The physical reality is a subtel mixing of these two optical manifestation types.

These present research project must be seen as a starting point to the comprehension of the optical deviation phenomenons.

In the first part of the work, we consider a glass plate composed by a superposition of various refractive index layers, and we simulate the optical response of this theoric glass plate, including surface effects. We considere also sinusoidal or cosinusoidal perturbations of the surfaces of these different layers. For solve this problem, we use a geometrical optic model, including multiple orders of internal reflections and refractions reliated by Fresnel coefficients, and we study the response due to the surface effects.

In the second part, we start from a real industrial glass plate and we solve the inverse problem to the part one. When we illuminate the glass plate, the optical response and the optical deviations permit to reconstruct numerically the global surfaces of this glass plate (including variations of the local refractive index). In the same way, if we repeat the mesures on the polished glass plate, we can separate the optical deviations of the surface effects from these of the mass effects.







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