3D Holographic Display with Enlarged Field of View Based on Binary Optical Elements

Abstract

Since Steve Jobs redefined mobile phones in 2007, scientists and engineers are exploring the next revolution of the smart phone. Holographic 3D display, presenting information in the same way as nature, is widely considered to be the game-changing technology. However, the performance (i.e., the refreshing rate and the field of view (FOV)) of holographic display is still unsatisfactory because of the current state of spatial light modulation (SLM). Recently, we have proposed a multiview holographic display technology using a LCD screen for refreshable amplitude information and a phase plate with a full coverage of pixelated nano-gratings for phase information of a light field function. The prototype demonstrated a 5.5 inch refreshable 3D display with full motion parallax and a horizontal field of view of 50 degree. However, the resolution of each view, the FOV, and the number of views is a balance in the proposed multiview 3D display system, which means an increased number of views and improved resolution of each view will lead to decreased FOV for a given LCD screen. Here we propose a holographic 3D display system using a binary optical element (BOE) to modulate the collimated illuminating light. The emergent light from each BOE pixel is split into multiple beams and directed to an enlarged vertical viewing angle. As a result, a larger FOV is achieved without sacrificing the number of views and the image resolution. In this paper, we first designed the required structure of the BOE by the optimized algorithm of the Fourier iterative algorithm. Then, we patterned the pixelated BOEs using a homemade lithography system and built up a $2.7 \text{cm} \times 3.6 \text{cm}$ 3D display prototype. Finally, the experimental results proved that the vertical FOV of the proposed 3D display system was enlarged without sacrificing the image resolution and the number of views.