UEC researchers have developed an optical plate that makes floating images clearer to the naked eye. The design reduces stray light and visual blur, improving image stability and visual cleanliness, and helping mid-air displays move toward practical augmented-reality applications.

Augmented reality (AR) brings digital content into the real world, but most systems today require users to wear headsets or glasses. These devices limit convenience and prevent groups from sharing the same view. An alternative is “mid-air imaging,” where images appear to float in space and can be seen with the naked eye. However, existing mid-air imaging technologies face two persistent challenges: limited viewing angles and stray light that degrades image quality and visual symmetry.

To address these issues, lead author Naoya Koizumi, together with Junpei Sano, developed a new optical plate called the truncated cylindrical array plate (TCAP). Rather than increasing spatial resolution compared with existing approaches, TCAP suppresses stray light and unwanted reflections, resulting in visually cleaner and more stable mid-air images that are easier to view and share.

Computer simulations showed that TCAP can form mid-air images symmetrically opposite the light source and achieve a wide horizontal viewing angle of up to about ±40 degrees. Compared with conventional cylindrical-array designs, the new structure produced brighter images with reduced interference, although mirror-based plates such as MMAP still exhibit higher peak brightness. Vertical viewing angles remain limited, and the primary improvement is in the horizontal direction, which is particularly beneficial for multi-viewer scenarios.

The team then fabricated a prototype using acrylic rods with mirrored sections to validate the optical principle. Tests with light sources and simple objects confirmed that mid-air images could be observed from multiple horizontal positions under controlled conditions. Measurements of brightness and resolution were consistent with theoretical predictions, supporting the underlying design concept.

Koizumi explains: “Mid-air displays allow people to share digital images naturally, without headsets or devices. By reducing stray light and improving visual clarity, our optical plate demonstrates a promising step toward more practical implementations of this technology.”

Potential applications include public information displays, medical visualization, and hands-free interfaces where shared viewing is advantageous. The researchers note that further improvements in image quality, viewing range, and fabrication will be necessary before everyday deployment.