In lighting applications key drivers for optical design of surface textures are integration of optical elements, the disentanglement of optical functionality and appearance and late stage configuration.
We investigated excimer laser ablation as a mastering technology for micro textured surfaces, where we targeted an increase in correspondence between surface design and ablated surface for high aspect ratio structures. To achieve this we have improved the photo mask design using a heuristic algorithm that corrects for the angular dependence of the ablation process and the loss of image resolution at ablation depths that exceed the depth of field. Using this approach we have been able to demonstrate close correspondence between designed and ablated facet structures up to 75° inclination at 75 μm depth.
These facet design parameters allow for total internal reflection (TIR) as a means of beam deflection which is demonstrated in a range of mono shaped cone arrays in hexagonal tessellation. BSDF analysis was used to characterize the narrow TIR deflection beams that matched the peak positions of the design down to 28° apex. In addition, a single surface TIR-Fresnel lens design with focal distance 5 mm has been manufactured using this photo mask design algorithm and beam collimation up to 12° beam angle and 32° field angle is shown.
These outcomes demonstrate that the laser ablation process intrinsically yields sufficient small dispersion in structure and fillet radii for lighting applications.
For miniature laser projection displays the laser beam is swept very fast back and forth with a MEMS mirror. This paper
presents an innovative design for such a MEMS mirror. Both the dynamical behavior and manufacturability have been
improved. We designed a process based upon industrially proven process steps to accurately control critical parameters
and fabricated a mirror consisting of: cantilever beams, out-of-plane support beams and a rhombus shaped enforcement
Measurements show a well defined resonant mode of operation at 23.5 kHz while suffering from only little parasitic
resonance modes. This mirror can now be mass-produced at low costs.
A new laser-assisted process called "Laser Die Transfer" is developed for high speed assembling of miniature electronic components. Silicon dies, fabricated on an optically transparent carrier are released using a laser pulse. This process has the potential to offer major advantages compared to existing transfer processes for future needs: high manufacturing speeds, contact-free, ability to handle very small and thin components. In this paper we present a thermal model, which describes the nonlinear behavior of silicon and carrier material under the influence of 1064 nm laser irradiation. The threshold intensities for die release and silicon damage will be explored as a function of operating laser beam characteristics. Experimental verification is presented to compare the simulated predictions and experimental results for the die release process.