Scientists have developed an ultra-thin 3D display with a wide viewing angle, clear images and expressive depth. The new product overcomes the usual difficulties for systems without 3D glasses and promises to be a breakthrough in the creation of detailed interactive systems in healthcare, education and entertainment.

“The new display is just 28mm thick, which is much thinner than traditional directional backlight systems, which typically exceed 500mm. This compactness, combined with a significant increase in resolution, represents an important step towards the practical application of this technology in real devices,” explained research team leader Xu Liu from Zhejiang University.

The test results of the 32-inch prototype were published in the magazine OPTICALand they are impressive: the viewing angle is than 120°, the image volume is 720x400x1000 mm.

“Our 3D display maintains image sharpness across the entire depth of the scene, which helps the user accurately perceive volume and spatial relationships. This, for example, could help doctors easily distinguish complex anatomical structures such as tumors or fractures in real time,” said Zhenmao Wu from Zhejiang University, co-author of the paper.

How 3D works without glasses

3D light field display technology creates images using directional illumination to precisely control light beams. This design allows each eye to see a slightly different image, creating a natural sense of depth without the need to wear special glasses. The quality of the 3D effect depends on the accuracy of the formation of voxels – the three-dimensional pixels that make up the image – as well as their number and size: the smaller and precise the voxels, the detailed and realistic the depth of the scene is.

“In light-field displays that use diffraction gratings or cylindrical lens arrays, the voxel size is fundamentally limited by the backlight scattering angle. Our system achieves much higher accuracy in voxel generation compared to existing 3D backlight displays, achieving better voxel miniaturization and a significant increase in resolution,” said Xinzhu Sun from Beijing University of Posts and Telecommunications, a key contributor to the work.

The main innovation of the display isfreeform opticsadvanced optical elements that use free-form surfaces to precisely control light. This provided the necessary design flexibility to create an ultra-thin yet large-area system. Each light-forming channel of the display combines an LED, an aperture and a free-form lens.

The developers have arranged these channels into a single large-area matrix. In addition, the display uses a module of two layers of micro-triangular prisms, which significantly improves illumination uniformity while maintaining the directional properties of light.

Obvious advantages over conventional displays

The prototype’s performance was assessed using a 50mm fixed-focus lens with an f/2.8 aperture, a setting often used to simulate the human eye’s perception of depth and sharpness. The display showed an image of an astronaut in outer space. It appeared three-dimensional over a continuous depth range of 1 meter with a viewing angle of than 120°.

The new product was also compared with its analogues and it was found that its voxels were six times smaller, and its visualization efficiency (essentially, the efficiency of converting a two-dimensional image into a three-dimensional one) was two orders of magnitude higher.

Researchers are currently working to further reduce the thickness and weight of the device while increasing its optical efficiency. To commercialize the development, it would not hurt to further reduce the voxels, increase their density and optimize their shape.