What They Say
The optics.org site has reported R&D work at Soochow University in China that is aimed at designing a nanostructured flat lens with an improved depth of focus. The work was published in the Optica journal.
“Most light field 3D displays have a limited viewing range, which causes the 3D virtual image to degrade as the observer moves farther away from the device. The nanostructured flat lens we designed is just 100 microns thick and has a very large depth of focus, which enables a high-quality virtual 3D scene to be seen from farther away.”
said research team leader Wen Qiao from Soochow University.
The research covers the development of a new diffractive flat lens based on patterned nanostructures. Intertwining these lenses creates a pixelated view modulator to create different views.
After showing that the lens achieved high resolution when focusing the red, green and blue light used by LCDs to create images, the researchers incorporated them into a 4-inch prototype 3D light field display with viewing distances between 24 and 90 centimeters.
The display formed a smooth horizontal parallax with a crosstalk below 26% over all viewing distances, which means there were few errors that would cause eye strain or make the image look unrealistic. The display also exhibited a light efficiency that reached 82%, said to be much higher than other similar 3D display systems that have been reported.
Although the prototype exhibited a viewing angle of only 9 degrees, the researchers say this could be enlarged to almost 180 degrees by optimizing the design of the nanostructures used to make the flat lenses. They plan to further improve the light efficiency by developing a more sophisticated design algorithm for manipulating the light beam at each pixel.
What We Think
This is, of course, R&D and the group acknowledges that an easier way to fabricate the nanostructures would be needed to make it practical to manufacture. Still it shows what is going on. (BR)
