Production of gratings by means of step and repeat hot embossing

Gratings are micro geometries that make use of diffractive effects in order to change the light performances, propagations, directions among the others. In lighting applications such gratings can be used in order to redirect light in defined directions. Lightguides including patterns, with diffractive grating patterns, offer advantageous properties in terms of light guiding and light redirecting performance. While the general mode of operation of such structured lightguides have been proven for small devices, large area lightguides require new production methods in order to allow for a production at reasonable costs. Within this paper the function and the geometry of diffractive gratings on lightguides will be explained. Subsequently, the step and repeat hot embossing process will be introduced as a particularly suitable process for the production of diffractive gratings on large surfaces. The concept for the machine system, which enables for an optimised step and repeat hot embossing process, will be explained.