Insect-inspired smartphone projector focuses images onto uneven surfaces
By Ben Coxworth
May 11, 2012
If you were using a smartphone projector to shine an image onto an uneven surface, or onto a flat surface but at a diagonal angle, parts of the image would end up out of focus ... unless, that is, your phone featured a new prototype LED projector developed by Germany’s Fraunhofer Institute for Applied Optics and Precision Engineering. Inspired by the compound eyes of insects, the device can reportedly display crisp, bright, distortion-free visuals onto irregular surfaces, and at non-perpendicular angles. Additionally, users can manipulate that display by reaching in and touching the projection surface.
The secret to the system is that it incorporates not just one projector, but an array of 200 microprojectors. Each one of those projects the same complete image, their shots all superimposed on top of one another on the wall – or whatever surface is being used. However, each microprojector can independently adjust the focus of its image, based on how far it is from the surface. If integrated into a smartphone, the phone’s position sensor and camera could be used to provide the necessary data.
What it all boils down to is that even if the picture were being projected onto a curved surface, every part of that surface would be reflecting an image that was custom-focused to its own unique distance from the array.
Besides being made up of 200 visible pictures, however, the image is also overlaid with a grid of infrared lines, invisible to the human eye. If the user sticks their fingers onto the projected image and starts doing the same sorts of things they would do on a touchscreen display, a sensor registers when and where those lines are broken, and the system reacts accordingly. The Fraunhofer researchers suggest that this could lead to smartphones that could be controlled from a large projected image of their screen, instead of from the cramped screen itself.
The entire LED projector system measure 2 x 2 centimeters (0.79 x 0.79 inches), and is reportedly well-suited to large-scale production. It may be a few years before it makes its way into commercially-available phones, however, as it requires quite a high pixel density in order to work properly.
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