Homogeneous LED illumination by functional microstrucruring.
Modern illumination elements like functional displays or LED panel lights are an important tool to design a visual appealing and valuable product. It is essential for these elements that the point source of the diodes (LED) are not visible and the illumination level appears constant. The functional display for a homogenous illumination includes a plastic diffusing lens or other lightguiding elements with diffusing structures. Therefore defined diffusing or decoupling structures are inserted into a transparent injection moulding part. The order and configuration of the structures is calculated by a simulation of the light intensity in dependence of the component's geometry (raytracing, light design).
The incoming light is reflected at the limitation of the component (total reflection) and is guided through the element (principle of light guiding). If a light beam reaches one of the integrated diffusing structures is leaves the component because its angle of incidence is much smaller than the angle of total reflection.
The advantage of this illumination method with LED panels is the high flexibility of the design, colour and intensity. Due to the high efficiency and the low costs there are many applications in the automotive sector (interior illumination, display illumination), the household (kitchen units, optical elements), the electronics sector or for advertisement.
Defined diffusing structures by using ultrashort pulse laser
The diffusing structures can be included into a plastic component or into an injection moulding component. Due to its high structure resolution and its melting free processing, the ultrashort pulse laser is particularly suitable for this procedure. The material is thermally unaffacted and no other material changes occur. The structures have a structural density distribution calculated for the component, which are included by the laser unit. A 2.5D processing allows to acces component positions that are hard to reach and to insert the microstructure pattern to the component. Due to the high quality and the melting free USP processing, the shape accuracy is so high that the brightness and the intensity profile appear absolutely homogeneous.