6mm Thick Pico Projector: World's Smallest Projectors

Imagine that you want to give a power point presentation at a business conference and the office projector doesn’t start at the eleventh hour. What will you do? You can either postpone the meeting or call someone to repair the printer or bring another printer and set it up. But if you are aware of this neat little projector, then you will carry this 6mm thick pico projector to the meeting as a backup option. Yes, it’s true. The scientists at the Fraunhofer Institute in Germany have designed a prototype of the world’s smallest projector which produces images that are 10 times brighter than any other device of the same dimensions.



This mini gadget is able to produce such bright images despite lacking the bulky lens assembly. This has been made possible because of the specially aligned arrangement of ultrathin microlenses. Each of these delicate and expertly crafted microlens comes with its very own tiny LCD (liquid crystal display). These handheld pico video projectors can display pictures, movie clips, maps and paper presentations. This prototype developed by Marcel Sieler and his team at the Fraunhofer Institute for Applied Optics and Precision Engineering was unveiled at the recently concluded Nano Tech 2011 festival in Tokyo, Japan.

Generally, when one tries to increase the brightness or intensity of a device, the surface area of the light source also needs to be enlarged. But increased surface area increases the volume of the lens making it thicker and heavier. This increases the size of the projector. However, the German scientists have come up with a unique plan that uses a different type of lens which focuses light from a big source but still remains very sleek. The concept model of the projector is made of 45 red, green and blue microlenses. Now, there is an individual LCD of 200x200 pixels behind each and every lens. The light rays passing through the displays are converged at a focal point with the help of lens to form an image and all these images are superimposed to obtain a final copy.

The resolution provided by this projector is comparable to that of a WVGA projector. It is approximately 800x480 pixels which are pretty good for its small dimensions. The pico projectors which are currently available in the market are 8 to 10 times bigger than this prototype but still possess a light intensity of 10 to 15 lumens whereas, this new pico projector provides 11 lumens intensity. If the size of this projector was made same as that of the other commercial pico projectors, then its intensity would have been 90 lumens! Now the next objective of the designers is to minimize the size of LCD pixels. The target is to reduce pixel length from 8.5 to 3 microns each.

To make the assembly more compact, the production engineers put the LCD behind the lens in between two transparent layers. One more problem in the design was the selection of the transparent material. Glass has such a high melting point the LCD would get damaged before the fabrication could be completed. On the other hand, the polymers melt at such a low temperature that they might liquefy due to the light source’s intensity. So the scientists at the Fraunhofer Institute for Silicate Research came up with a new transparent compound which is a hybrid of organic and inorganic materials. This material is totally transparent in the visible spectrum and can be processed just like a normal optical polymer. If this device is a commercial success then it could be easily integrated in our smart phones making them even smarter.