A lot of information can be found about three-dimensional displays of various designs and types. But if you trace this information in chronological order, you can see that work and research in this direction has been taking place in waves, now at a standstill, then resuming with renewed vigour. And now, apparently, we are at the beginning of a new wave of research activation. The first "swallow" of this is a new prototype 3D display created by researchers from Suzhou University, China. The new display works by using a matrix of special nanostructured lenses, it creates a more realistic image, visible at a greater viewing angle and distance, and does not require special glasses or other optical devices to view the image.
Some 3D display implementations have already found their way into the consumer market. Televisions, computers, smartphones and even Nintendo 3DS gaming consoles have been equipped with such displays. Unfortunately, none of these implementations are without some problems, chief among which are low viewing angles and shallow depth of the resulting image.
Chinese researchers tried to solve the above problems using so-called "light field" technology. Systems based on this technology project a dense network of rays that intersect to create a three-dimensional image effect visible from multiple points.
The key to the design of the new display is a matrix of nanoscale structures that diffract light in a precisely defined pattern. These structures, a kind of tiny lenses, are grouped and positioned at different angles to one another. That's what allows you to widen the angle of view of the image, although it's fair to say that people looking from different angles will see images that differ slightly in brightness.
"The nanostructured plane lens we created, which is 100 microns thick, has a rather long focal length," the researchers write, "This, in turn, allows high-quality images to be created with great depth and visible from a greater distance."
The prototype 3D display is 10 by 10 centimetres, with a resolution of 568 x 320 pixels per viewer's eye. Without any loss of quality, the image can be seen from a distance of between 24 centimetres and 90 centimetres. The luminous efficiency of the display is 82 per cent, while the "mutual penetration" (blurring of images for each eye) is reduced to 26 per cent.
The main drawback of the first prototype is the small viewing angle of just nine degrees. In other words, the 3D effect is disrupted as soon as the viewer veers away from the desired direction. However, scientists have already calculated the structure of new nanolenses, which will provide a wider viewing angle, which could theoretically become equal to 180 degrees.
Currently, researchers are working in several directions at once. The first direction is the calculation and creation of new structure of nanolenses, which will increase luminous efficiency and widen the viewing angle, as mentioned above. And the second direction is to develop a process for mass production of nanostructured planar lenses, which would allow such displays to be produced in large quantities in the future.
