10 Feb 2006
A patented micro scanning mirror is key to Fraunhofer IPMS's latest laser projector technology.
Mobile, miniaturised full-color laser projection systems might be a step closer to market-reality thanks to work being carried out at the Fraunhofer Institute for Photonic Microsystems (IPMS) in Germany. The team has developed monochromatic projection units, the size of two sugar cubes, and is aiming for full color projection by summer 2006.
"We have monochrome projection systems available for all three elementary colors. That means the only remaining step for full color projection is to combine three laser beams into one 'white' beam that is directed onto the micro scanning mirror. We are still optimistic that we can demonstrate a full color projection system in first half of 2006," Michael Scholles, business unit manager for the Institute, told optics.org.
The monochromatic images have a resolution of 640 x 480 pixels (VGA), 256 brightness levels per pixel, and are produced at a frame rate of 50Hz. In collaboration with Fraunhofer IOF, IPMS has also produced a 17mm x 7mm x 5mm projector head for an industrial customer; this includes the laser source, collimator optics and mirror.
The key to the projection system is IPMS's patented MOEMS micro scanning mirror. This oscillates, and deflects a modulated laser beam in both axes, to form regular Lissajous patterns. A control circuit coordinates this process to form images on a screen. Scholles adds, that the system requires no focusing optics.
"Until now, two key elements were missing for miniaturized laser projection systems: electrically modulated laser sources for all three colors and small, robust micromechanical devices for light deflection," said Scholles. "The first problem has been solved by leading laser manufacturers. The second gap is filled by our two-dimensional resonant micro scanning mirror that can be manufactured in large quantities. I see no remaining obstacle for laser projection systems targeting the markets."
The system is aimed at applications where ultra-compact projection heads are necessary, such as integration into mobile devices or applications in infotainment, automotive, medical, and metrology industries. "For a number of applications, full color is essential, however, other markets, especially for industrial applications, are satisfied with monochrome systems already," said Scholles.
Scholles says that IPMS is already producing a 1-D version of the micro scanning mirror in large quantities for an industrial customer, who will use the device in barcode readers. The researchers are currently working on further miniaturization of the projector head.
The monochromatic projector was demonstrated at Photonics West in January. Scholles says people should watch out for more details in June at Society of Information Display 2006 exhibition.