Multiview three-dimensional (3D) displays can project the correct perspectives of a 3D image in many spatial directions simultaneously1,2,3,4. They provide a 3D stereoscopic experience to many viewers at the same time with full motion parallax and do not require special glasses or eye tracking. None of the leading multiview 3D solutions is particularly well suited to mobile devices (watches, mobile phones or tablets), which require the combination of a thin, portable form factor, a high spatial resolution and a wide full-parallax view zone (for short viewing distance from potentially steep angles). Here we introduce a multi-directional diffractive backlight technology that permits the rendering of high-resolution, full-parallax 3D images in a very wide view zone (up to 180 degrees in principle) at an observation distance of up to a metre. The key to our design is a guided-wave illumination technique based on light-emitting diodes that produces wide-angle multiview images in colour from a thin planar transparent lightguide. Pixels associated with different views or colours are spatially multiplexed and can be independently addressed and modulated at video rate using an external shutter plane. To illustrate the capabilities of this technology, we use simple ink masks or a high-resolution commercial liquid-crystal display unit to demonstrate passive and active (30 frames per second) modulation of a 64-view backlight, producing 3D images with a spatial resolution of 88 pixels per inch and full-motion parallax in an unprecedented view zone of 90 degrees. We also present several transparent hand-held prototypes showing animated sequences of up to six different 200-view images at a resolution of 127 pixels per inch.
We are grateful to C. Santori for many suggestions on the backlight design, A. Jeans for performing the roll-to-roll imprint jobs, A. Said for generating some of the multiview images shown in Fig. 2, L. Kiyama and W. Mack for the printed circuit board design of the portable prototypes, R. Cobene for his help with packaging, P. Beck for her help in the cleanroom, and B. Culbertson and C. Patel for their support of the project.
This video highlights the main features of our multi-directional backlight technology: large view angle, spatial multiplexing of colors, compact form factor, portability and transparency.
This video briefly explains the roll-to-roll imprint process that can be used for the mass-production of static 3D backlight patterns, and compares the result with a prototype made by electron beam lithography.
This video shows various static 3D images in color, created by aligning a printed ink mask on top of a 6 inch diameter backlight. Note the large amount of motion parallax.
This video shows the active modulation of an inch-size backlight by a commercial LCD shutter device. Only a fraction of the LCD is functional due to thinning of the top cover glass, yet video-rate modulation of 14 views is demonstrated.