Three dimensional (3D) display is the device that enables a user to perceive depth of an image for a given object. Holography is an ideal 3D display technology that can reconstitute both the intensity and wave-front information of an object. But the recording media are too slow to provide real-time perceive for viewers. Alternatively, electronic holography is considered to be a promising 3D display method. Limited by the refreshable data volume, however, the state of the art SLM can hardly offer satisfactory 3D video. Over the past 100 years, multiview 3D displays based on pure geometrical optics, such as parallax barrier, lenticular, or a combination of both, have been proposed and studies extensively, yet they are criticized for providing only horizontal-parallax, limited number of viewing zones, reduced brightness, limited resolution, and visual fatigue.

Supported by the National High Technology Research and Development Program of China, SVG’s team proposed a novel light-field display technology. By using a diffractive element to separate the phase information from the refreshable information, light-field display based on diffractive optics provides wide viewing angle and small volume of processing data. First, we proposed a lithography system to fabricate DOE elements at a high throughput. The period of the periodic structures can be tuned at a step as small as 1 nm. The fabricated lightfield modulator was then paired up with a refreshable LCD screen. The beauty of our technology lied in the phase modulation of 3D information: the five dimensional light-field information can be expressed by the nano-structures. Finally, a chromatic and dynamic light-field display with smooth transitions was created. Our light-field modulation technology provide a 3D expreience to observers without visual fatigue. The light-field display technology can be either integrated with large screen for applications such as TV and game station, or integrated in a compact format for portable electronics. 

5.5-inch LCD display whit a pixel-shaped nano-grating light guide plate

Dynamic monochrome 3D image display

Dynamic color 3D image display

video1、video2

References：

1. Efficient fabrication method of nano-grating for 3D holographic display with full parallax views, Wenqiang Wan, 21 Mar 2016, Vol. 24, No. 6, OPTICS EXPRESS
2. Multiview holographic 3D dynamic display by combining a nano-grating patterned phase plate and LCD, Wenqiang Wan, 23 Jan 2017, Vol. 25, No. 2, OPTICS EXPRESS