Reichle has successfully developed a precision light extraction element using the latest femtosecond laser technology from GF Processing Solutions. This element is almost invisible on transparent plastic at room temperature, but creates a uniform surface light guide when exposed to light.
Lighting applications, especially in the automotive industry, are gradually becoming more intelligent, design-oriented and personalized. Accordingly, the technology underneath the surface material coverings of automotive lighting is becoming more and more advanced and sophisticated. But what if the surface material is transparent? How do you balance optical functionality and surface aesthetics when there is no place to hide these intricate optical components?
Laser texturing service provider Reichle and its partner in optical illumination, Lightworks, have been working on this problem for the past year and have redefined the possibilities of surface light guiding on transparent surfaces with the development of Hyperion (transparent illumination technology). At room temperature, it's a simple-looking glass-like plastic sheet, but when light comes from the side and generates a certain temperature, the surface reveals an incredibly homogeneous luminescent structure that opens up unprecedented possibilities in the field of indoor and outdoor lighting.
The biggest challenge in implementing this project was that the optics had to be virtually invisible when not illuminated and as bright and uniform as possible when illuminated. To achieve this, Lightworks and Reichle worked closely together to simulate and calculate millions of optical structures and features, and then laser textured them using the latest femtosecond laser technology from GF Machining Solutions. Traditional milling, chemical erosion or similar alternative processes had reached their limits and were therefore unable to meet current demands.
In order to maintain glass-like transparency on plastics, Lightworks and Reichle have developed new optical microstructures that are much smaller than conventional optical microstructures. While conventional common sizes are at least 100µm, the newly developed optical microstructures are much smaller. To be able to process at this size, Reichle used femtosecond laser technology, the most advanced and precise laser technology in the world.
With this technology, high-precision machining with radii of approximately 0.01 millimeters (10µm), sharp edges and vertical geometries can be achieved, and even the wear resistance of surfaces can be improved. Such delicate and fine structures can only be realized with this level of femtosecond precision and a laser beam that is as small as possible.
Continuous parametric research, materials testing, optical simulations, optical testing and other special experiments in the Lightworks Lighting Lab have resulted in the design of optical elements that no longer require diffusing screens or diffusers. Now, specially designed optics not only ensure uniform light distribution and controlled brightness profiles, but also eliminate imperfections such as uneven brightness. Even structures with tiny dimensions can be designed and machined. In this way, various logos, symbols, texts, graphics and other elements can be incorporated into transparent plastic surfaces that are virtually invisible at room temperature and only appear when the temperature rises. Even continuous surfaces as full-surface light guides are possible.
This concept can either be integrated directly into transparent plastic parts for customization or prototyping, or it can be realized directly in injection molds and thus used for mass production.
This new process of changing the microstructure can be used not only for surface light guides, but also for functional optics in lenses and thick-walled optics for headlights and taillights, transparent parts for front and rear headlights, interior ambient lighting and even windows. It can also be applied to interior components such as gear levers, steering wheels, displays and buttons. It is clear that its application possibilities will soon extend beyond the automotive industry into a wide range of fields such as aviation cabins, homes and electrical appliances.
