The combination of a new kind of optical structure with high-performance LEDs enables completely new compact and brilliant lighting and projection systems.
Marcel Sieler of the Fraunhofer Institute for Applied Optics and Precision Engineering IOF in Jena developed the bases for an entirely new kind of design in order to realize mini-projectors.
In all current systems of pocket projectors, a single imaging channel is used. This means a minimal size for the projector is a given ? and smaller will not work. Except for Marcel Sieler: His construction method relies on a number of regularly ordered micro-lenses ? an array ? as the projection lens. Thanks to the many channels, the construction length of the entire system can be clearly reduced, without impeding luminosity. A high-performance LED is used as the light source.
In order to achieve this result, in his thesis project, Sieler initially tested and adapted the theoretical basis for the construction of a micro-lens array. He then devised a corresponding system that was characterized in laboratory experiments and tested for its optical performance capacity. Within nine months, Marcel Sieler transformed his idea into the first prototypes. With these, he could display the immense potential of the concept with which both static as well as mobile image contents can be projected. Based on Marcel Sieler's work, the Fraunhofer-Gesellschaft was able to apply for a basic patent for this new kind of optical system.
The prototype projector is just six millimeters thick, but it produces images that are 10 times brighter than would normally be possible with such a small device. Its resolution is
close 800 by 480 pixels. The new projector has a brightness of 11 lumens, compared to 10 to 15 lumens for existing pico projectors.
The new prototype will be demonstrated at the Nano Tech 2011 conference in Tokyo later this month.