Researchers have developed a new, ultra-thin film that can create detailed 3D images that can be viewed under normal lighting without any special reading devices. Images seem to float on top of the film and show a smooth parallax, meaning they can be seen clearly from all angles. With further development, the new glass-free approach can be used as a visual safety feature or integrated into virtual or augmented reality devices.
“Our ultra-thin compact reflective imaging film creates an image that can be seen from a wide range of angles and appears to have physical depth,” said research team leader Su Shen from Soochow University in China. It can be easily laminated onto any surface as a tag or label or incorporated into a transparent substrate, making it suitable for use as a security feature on banknotes or ID cards.
In Optica Publishing Group Optics Letters, the researchers describe their new imaging film. At only 25 microns thick, the film is about twice as thick as household plastic wrap. It uses a technology known as light field imaging, which captures the direction and intensity of all light rays within a scene to create a 3D image.
“Achieving glass-free 3D imaging with a wide field of view, smooth view, wide depth range and focusable under natural viewing conditions is one of the most exciting challenges in optics,” said Shen. “Our approach offers an innovative way to obtain vivid 3D images that do not cause discomfort or fatigue during viewing, are easy to see with the naked eye and are aesthetically pleasing.”
High Density Recording
Various technical schemes have been examined to create the perfect 3D viewing experience, but they tend to suffer from drawbacks such as limited viewing angle or low light efficiency. To overcome these shortcomings, the researchers developed a reflective film for light field imaging and a new algorithm that allows the location and angle information of the light field to be recorded at high intensity.
The researchers have also developed an economical approach to nanoprinting lithography that can achieve the resolution required for high optical performance while using low-cost materials. The image to display.
“The microfabrication method we used allowed us to make a reflective focus that was extremely compact—measuring only tens of microns,” Shen said. “This allows the light beam to be densely collected, creating a realistic 3D effect.”
Realistic 3D picture
The researchers demonstrated their new film by using it to create a 3D image of a cube mold that can be clearly seen from almost any vantage point. The resulting image has dimensions of 8 x 8 mm with an image depth of 0.1 to 8.0 mm in natural lighting conditions. They have also designed and manufactured a photographic film with a floating logo that can be used as a decorative element, for example on the back of a mobile phone.
The researchers say the algorithm and the nanotransformation technology could be extended to other applications by creating the nanopatterns on a transparent display screen instead of on film, for example. They are also commercializing the manufacturing process by developing a nano-duplex printing machine that makes it easy to achieve the exact alignment required between the fine patterns on each side of the film.
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