Researchers at the Fraunhofer Institute in Germany have developed a video projector as small as a sugar cube. This projector contains only a single mirror which can be rotated around two axes. So it is very small, but a big problem remains before a possible commercialization. Light sources also need to be miniaturized. Red and blue diode lasers are small enough to fit in such a mini-projector, but green ones are still too big. So you will not find such a projector in PDAs or cellphones before a while. But read more...
The Fraunhofer Research News article starts by explaining why projectors are still too expensive to enter the consumers market.
All attempts at miniaturization have so far come up against certain physical boundaries: the core piece of the classic projector is a micromirror array comprising a million mirrors. These can be tilted in one plane and are evenly illuminated. By turning towards or away from the light source, they produce light or dark pixels that together form the projected image.
And of course, this prevents projectors to be both small and affordable.
Researchers at the Fraunhofer Institute for Photonic Microsystems IPMS in Dresden and the Fraunhofer Institute for Applied Optics and Precision Engineering (IOF) in Jena have now come up with an alternative to the previous micromirror arrays. The result is a projector the size of a sugar cube. "We use just one single mirror," reveals Andreas Bräuer, director of the Microoptic Systems division at IOF.
As you can see below, this projector would be roughly the size of a coin of one cent of euro -- which has a diameter of 16.25 millimeters (Credit: Fraunhofer IOF). Here is a link to a larger version.
And below is a picture showing one of the possible usages for such a small projector: showing a presentation to a customer (Credit: Fraunhofer ISIT). This image has been extracted from page 51 of a special issue of Fraunhofer magazine focused on Nanostructured surfaces (PDF format, 52 pages, 2.87 MB, February 2005).
So if such a projector can be produced, what are we waiting for?
The next obstacle in the miniaturization process is the light source. The customary high-pressure lamp will have to give way to small diode lasers if the projector is to shrink to the size of a sugar cube. While red and blue diode lasers are already small enough, green lasers are still too bulky.
So the Fraunhofer researchers are now waiting for a technical solution which would reduce the size of green diode lasers to the size of red ones.
When it is done, we'll get mini-laser projectors in our phones and laptops.
For more information, you also can read a previous post, "A Video Projector that Fits in Your Pocket," to see how the technology has evolved since 2004.
Sources: Fraunhofer-Gesellschaft Research News, September 2006; and various websites
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