Optical see-through near-eye display based on dot matrix nanogratings

In this paper, we propose a phase modulator based on dot matrix nanogratings for realizing a super multiview display for optical see-through near-eye display applications. The phase information of a three-dimensional scene can be modulated by the phase modulator to form a series of viewing points in front of the human eyes, and the pitch of the viewing points can be confined to be smaller than the pupil diameter of the human eye by designing the diffraction vector of each nanograting in the phase modulator. Here, we fabricated a 2-inch 4-view phase modulator with full coverage of dot matrix nanogratings using continuously variable spatial frequency photo-lithography. Under the illumination of a collimated laser beam with a wavelength of 532 nm, the emergent light was converted into 4 well-separated viewing points with a separation distance of 2 mm, and the angular divergence of the viewing point was measured to be 1.14 degrees on average, which slightly exceeds the diffraction limit (0.93 degrees). By using a transmissive liquid-crystal panel that loaded the amplitude information of the perspective images of a three-dimensional scene, we experimentally demonstrated that the proposed see-through near-eye display can display three-dimensional images with correct depth cues, enabling observation that is unhindered by the vergence-accommodation conflict and the visual fatigue problem.