AR/VR equipment has its own defects, for example, due to its design based on body vision or self-vision, it is easy to cause visual motion sickness or other visual interference after long use.One promising solution is to apply holographic or optical field technology to the device.However, this requires additional optical devices to increase the size, weight and cost of these devices - which have so far been unable to meet the challenge of commercial success.
Now, a group of researchers in Japan and Belgium has begun to explore a combination of holography and light field technologies as a way to reduce the size and cost of more people-friendly AR/VR devices. They will present their work during The Optical Society's (OSA) Frontiers in Optics meeting, 16-20 September, in Washington, D.C.
"Objects we see around us scatter light in different directions at different intensities in a way defined by the object's characteristic features -- including size, thickness, distance, color, texture," said researcher Boaz Jessie Jackin of the National Institute of Information and Communication Technology in Japan. "The modulated [scattered] light is then received by the human eye and its characteristic features are reconstructed within the human brain."
Devices capable of generating the same modulated light -- without the physical object present -- are known as true 3-D displays, which includes holography and light-field displays. "Faithfully reproducing all of the object's features, the so-called 'modulation,' is very expensive," said Jackin. "The modulation required is first numerically computed and then converted into an optical signal via a liquid crystal device (LCD).These signals are then received by other optical elements, such as lenses, mirrors, beam splitters, and so on.
This is where holographic optical elements can make a big difference. "A holographic optical element is a thin sheet of photosensitive material -- think photographic film -- that can replicate the functions of one or more additional optical components," said Jackin. "They aren't bulky or heavy, and can be adapted into smaller form factors. Fabricating them emerged as a new challenge for us here, but we've developed a solution."
The group decided to print/record the hologram digitally, calling the solution a "digitally designed holographic optical element" (DDHOE). They use a holographic recording process that requires none of the optical components to be physically present during the recording, yet all the optical components' functions can be recorded.
In terms of applications, the researchers have already put DDHOE to the test on a head-up light field 3-D display. The system is see-through, so it's suitable for augmented reality applications.
The researchers went on to create a head-up, see-through 3-D display, which could soon offer an alternative to the current models that use the bulky collimation optics.