Existing 3D screens that do not require glasses, including Nintendo’s recently launched 3DS handheld console, can only be viewed from specific angles.
But the new technology from Microsoft’s Applied Sciences Group in Redmond, Washington, uses cameras to track viewers’ positions and alter the angle of projection. Sending different images to viewers’ right and left eyes creates the 3D effect.
‘The technology is scalable and applicable to all device sizes from mobile phones to laptops to large walls,’ Stevie Bathiche, the group’s research director, told The Engineer. ‘The approach stays low cost even on very big screens.’
The system uses a wedge-shaped lens to steer light from movable light-emitting diodes (LEDs) to the viewers’ eyes. Light enters at the thinner, bottom end of the lens and bounces around until reaching the desired angle and emerging from the front of the lens.
A camera at the bottom of the lens tracks the viewers by collecting light coming the other way through the lens and the angle of the LEDs changes to correspond to the viewers’ movements.
The system can support two viewers watching 3D images or four viewers watching ordinary video. As the lens is so thin (between 6mm and 11mm), it could be used to replace the backlight of an LCD TV.
‘We have demonstrated various applications of the technology in the laboratory but have not built a full product prototype,’ said Bathiche. ‘Simpler applications of the technology could reach the market sooner, but applications offering altogether new levels of functionality will take longer.’
High-volume production and image quality are the biggest challenges facing the team, he added. ‘The optical components in cameras and DVD players are tiny, while our optics have to be the size of the screen yet cost much less than the optics in a screen-sized telescope.
‘It’s not as big a step as it may sound because off-the-shelf transparent plastic sheet already has surprisingly high quality, but getting the shape just right without losing the transparency is more challenging than the moulding of conventional opaque plastics.’