Volumetric Displays: Bring 3D projection closer to reality

Projecting an object in a 3D format is a fantasy we all share. From the likes of Star Wars to Black Panther, we have seen numerous sci-fi movies use the concept of 'volumetric display' to present 3D information in real 3D space. But now, researchers have proved that we are close to achieving this concept into an everyday reality. According to a study published in Nature in 2018, a team of scientists have figured out how to manipulate nearly unseen specks in the air and use them to create 3D images that are more realistic and clearer than holograms. The study's lead author, Daniel Smalley, a physicist at Brigham Young University in Provo, Utah and his team had created a small butterfly appearing to dance above a finger and an image of a graduate student imitating Leia in the Star Wars scene.

Referred to as "optical trap display" the technology uses forces conveyed by a set of near-invisible laser beams to trap a single particle — of a plant fiber called cellulose and heat it evenly. That allowed the team to push and pull the cellulose around. Then the second set of lasers project visible light (red, green and blue) onto the particle, illuminating it as it moves through space. Humans cannot discern images at rates faster than 10 per second, so if the particle is moved fast enough, its trajectory appeared as a solid line, like a sparkler in the dark.

In a volumetric display, the "screen" is, in a sense, scattered throughout the image volume itself: light diverges from scattering or emissive point primitives within the volume to form the image in physical space. It offers spatially accurate representations of images with a 360° view, but have been challenging to implement due to complex fabrication requirements. Further, its operating principle relies on photo-activated dyes that become reversibly fluorescent upon illumination with ultraviolet light. In 2017,  a team at Utsunomiya University's Kumagai Yukinobu campus showed their research on volumetric display by creating a stereoscopic image using just bubbles in a transparent liquid that were then colored with laser light.

According to Gartner, true volumetric displays are of two types, viz., swept volume displays and static volume displays. The swept volume displays employ the persistence of human vision to re-create volumetric images from rapidly projected 2D "slices." Meanwhile, the static volume displays rely on a 3D volume of active elements like Volumetric Picture Elements, or voxels, and changing color or transparency to display a solid option.

Though this technology is in an embryonic stage, scientists claim it has huge potential and offers major advantages. For instance, volumetric displays do not put much strain on eyes as we perceive this immersive display as a real-world 3D object. This is an upgrade from VR displays. Also, neither does it require any headset like AR-VR. Further, these volumetric displays can work on any 3D input device like Kinect, Leap Motion, and Structure. Speaking about applications, one can use the volumetric display for 3D Human Size communications like in Sci-fi movies where humans appear in projected forms for a top-secret mission. In the medical and healthcare industry, this display can be used for a number of use cases, including surgical planning, post-op review, training, doctor-patient communication, and diagnosis. Lastly, it also promises to bring a major revolution in the field of gaming. At present, the major companies present in this market include 3DIcon Corporation (US, LightSpace Technologies Inc. (US), Voxon (US), Holografika Kft. (Hungary), Zebra Imaging (US).