We study the possibility of the fabrication of faceted structure with a standard additive fabrication technology using the 3D printer of Objet30 Prime series from Stratasys. The structure contains a small number of facets with size in millimeter: these facets are inclined in two directions. We use analytical expression to solve the tilt angles recorded into a matrix. After obtaining the desired illumination pattern, we try to fabricate the structure with a standard and commercial additive fabrication methods (3D printing) to make a master. We create the STL file usable for the 3D Printer. First tests were made with the printer of the Stratasys Model Objet30 Prime using the material of VeroWhite Plus FullCure 835 and the support model of FullCure 705 from FABLAB at INSA Strasbourg. The common dimension of the element is 6 × 6 facets, where one facet is in millimeter. As printing is conducted with the material of VeroWhite, the quality of the surface profile of the printed model is not sufficient for direct optical applications due to the porous property of the material. As a result, square silicon mirrors are cut and coated with a 100 nm aluminum layer in a second step. Professional adhesive of NHU series from Hart Kunststoff, Germany is used to glue the mirrors on the faceted structure with delicate operation. Then the surface profile of the glued mirrors on the faceted structure is measured with a Zygo Newview 7200 profilometer. A first optical test gives interesting results, but not sufficient for our applications, but this work is an innovation and can give new creativity at the frontier of design and optical applications.
The re-direction of incoherent light using a surface containing only facets with specific angular values is proposed. A new photometric approach is adopted since the size of each facet is large in comparison with the wavelength. A reflective configuration is employed to avoid the dispersion problems of materials. The irradiance distribution of the reflected beam is determined by the angular position of each facet. In order to obtain the specific irradiance distribution, the angular position of each facet is optimized using Zemax OpticStudio 15 software. <p> </p>A detector is placed in the direction which is perpendicular to the reflected beam. According to the incoherent irradiance distribution on the detector, a merit function needs to be defined to pilot the optimization process. The two dimensional angular position of each facet is defined as a variable which is optimized within a specified varying range. Because the merit function needs to be updated, a macro program is carried out to update this function within Zemax. In order to reduce the complexity of the manual operation, an automatic optimization approach is established. Zemax is in charge of performing the optimization task and sending back the irradiance data to Matlab for further analysis.<p> </p> Several simulation results are given for the verification of the optimization method. The simulation results are compared to those obtained with the LightTools software in order to verify our optimization method.