Immersive Ultra-Thin 3D Display: Crystal-Clear Images from Every Angle

Researchers have introduced a cutting-edge ultra-thin 3D display with exceptional image quality, wide viewing angles, and striking display depth. This breakthrough overcomes the usual limitations of glasses-free 3D displays, opening up new opportunities for detailed interactive experiences in various fields like healthcare, education, and entertainment.

“The new display is remarkably slim at just 28 mm, a significant reduction compared to traditional directional backlight systems that are typically over 500 mm thick,” explained Xu Liu, the lead researcher from Zhejiang University in China. “This level of compactness, coupled with the substantial resolution enhancement we achieved, marks a crucial advancement towards making this technology viable for real-world applications.”

In a publication in Optica, the team showcased a prototype of a 32-inch ultra-slim directional backlight-based 3D display based on the new design. The prototype, approximately the size of a large computer monitor, boasts a wide viewing angle exceeding 120° and a substantial 3D display volume of 28 × 16 × 39 inches.

“The 3D display maintains sharp image quality throughout the entire imaging depth, aiding users in visualizing depth and spatial relationships for tasks necessitating precise spatial comprehension,” stated Rengmao Wu from Zhejiang University, the corresponding author of the study. “For instance, this technology could enable doctors to easily observe intricate anatomical structures like tumors or fractures in real-time.”

Experiencing 3D without glasses

3D light field displays generate a scene by utilizing a directional backlight to precisely direct light. This design allows each eye to perceive a slightly different image, resulting in a natural sense of depth without the need for 3D glasses. The quality of the 3D effect produced depends on the accuracy of constructing voxels – the 3D pixels that form the image – as well as their quantity and size. Smaller, well-constructed voxels enable finer details and more realistic depth.

“In light field displays employing diffraction gratings or cylindrical lens arrays, the size of voxels is fundamentally limited by the angular spread of backlight illumination,” noted Xinzhu Sang from Beijing University of Posts and Telecommunications in China, who made significant contributions to the project. “Our system significantly enhances the accuracy of voxel construction compared to existing scattering backlight-based 3D displays, achieving highly miniaturized voxels and substantial resolution improvement.”

Freeform optics – advanced optical elements utilizing freeform surfaces to precisely manipulate light – provided the necessary design flexibility to create the ultra-slim yet expansive directional backlight system. Each beam-shaping channel of the display integrates an LED source, an aperture, and a freeform lens that accurately redirects incident light to generate uniform illumination with precise directionality. These beam-shaping channels were arranged to form a customized large-area directional backlight system. The display also incorporates a module with two layers of micro-triangular prisms to significantly enhance backlight irradiance uniformity while maintaining directionality.

Advantages over traditional displays

After developing a 32-inch prototype based on the new design, the researchers assessed its performance using a 50-mm fixed-focus lens with an f/2.8 aperture, a setup commonly used to simulate the human eye’s perception of depth and clarity.

In one experiment, they used the ultra-thin 3D light-field display to visualize images of an astronaut floating outside a space station. The display showcased a continuous depth range of 1 m and a viewing angle exceeding 120°, delivering an immersive and lifelike visual experience.

Comparing the new design with conventional scattering backlight displays, they discovered that it produced voxels six times smaller and maintained resolution even at farther distances. Additionally, the display was approximately 100 times more efficient at utilizing visual information to generate images compared to scattering backlight displays.

The team is currently focused on further reducing the device’s thickness and weight while enhancing its optical efficiency. They emphasize the need for additional work to develop smaller pixel structures, increase pixel density, and optimize pixel shape to improve compatibility with 3D display technology for commercialization.