Video displays that offer both 2-D and 3-D imaging without the use of eyewear are very popular to consumers worldwide. Viewers, however, usually have to watch from a distance of around one meter. This eradicates the application of this technology to mobile devices. But researchers at Seoul National University, South Korea, have simplified and shrunk the architecture of the technology to convert these displays for near-viewing capabilities.
In a paper published in the journal Optics Express from The Optical Society, the researchers described their revolutionary design. The typical eyewear-free display features action behind the screen where the images' pixels and optics are layered together to produce the stereoscopic effect, where two photographs of the same object taken at slightly different angles are viewed together. The two primary ways of producing these optically illusive effects are by using either an array of micro-lenses called lenticular lenses or an array of micro-filters called parallax barriers.
These layers are active in 2-D or 3-D convertible screens that could be electronically switched on or off. Closer stacking of these layers together allows for a closer viewing distance since the gap between the image layer and the barrier layer is the key determinant of the viewing distance.
Sin-Doo Lee, a professor of electrical engineering at Seoul National University, and his colleagues have combined the active parallax barrier, a polarizing sheet, and an image layer into a single panel. Instead of two separate image and barrier panels, they used a polarizing interlayer. The use of this interlayer results in minimum separation of the image and barrier layers and allows for the short viewing distance required for the smaller screens of mobile devices. This technology will offer application to a broad range of present and future device designs.
"The polarizing interlayer approach here will allow high resolution together with design flexibility of the displays, and will be applicable for fabricating other types of displays such as viewing-angle switchable devices," Lee revealed. "Our technology will definitely benefit display companies in manufacturing low cost and light weight 2-D/3-D convertible displays for mobile applications. Under mobile environments, the weight is one of the important factors."