Efficient fabrication method of nano-grating for 3D holographic display with full parallax views

Abstract

Without any special glasses, multiview 3D displays based on the diffractive optics can present high resolution, full-parallax 3D images in an ultra-wide viewing angle. The enabling optical component, namely the phase plate, can produce arbitrarily distributed view zones by carefully designing the orientation and the period of each nano-grating pixel. However, such 3D display screen is restricted to a limited size due to the time-consuming fabricating process of nano-gratings on the phase plate. In this paper, we proposed and developed a lithography system that can fabricate the phase plate efficiently. Here we made two phase plates with full nano-grating pixel coverage at a speed of 20 mm²/mins, a 500 fold increment in the efficiency when compared to the method of E-beam lithography. One 2.5-inch phase plate generated 9-view 3D images with horizontal-parallax, while the other 6-inch phase plate produced 64-view 3D images with full-parallax. The angular divergence in horizontal axis and vertical axis was 1.5 degrees, and 1.25 degrees, respectively, slightly larger than the simulated value of 1.2 degrees by Finite Difference Time Domain (FDTD). The intensity variation was less than 10% for each viewpoint, in consistency with the simulation results. On top of each phase plate, a high-resolution binary masking pattern containing amplitude information of all viewing zone was well aligned. We achieved a resolution of 400 pixels/inch and a viewing angle of 40 degrees for 9-view 3D images with horizontal parallax. In another prototype, the resolution of each view was 160 pixels/inch and the view angle was 50 degrees for 64-view 3D images with full parallax. As demonstrated in the experiments, the homemade lithography system provided the key fabricating technology for multiview 3D holographic display.

Foveated glasses-free 3D display with ultrawide field of view via a large-scale 2D-metagrating complex

“…Furthermore, the axial movement and axial rotation of the BOEs between two Fourier transform lenses lead to variations in the scaling factor of periods and orientation of the patterned 2D metagratings 51 , respectively (Fig. 2c ).…”

Holographic Sampling Display Based on Metagratings

“…The fabrication of the view modulator with the capability to tune the period and the orientation of metagratings at sub-nanoscale is not trivial. A versatile homemade interference lithography system (Wan et al., 2016) was developed in order to generate finely controlled metagrating parameters at different spatial locations. The periodic variation of patterned metagrating is mechanically controlled by the longitudinal travel distance of the diffractive grating placed in a 4F system (Figure S3).…”

56‐2: Tabletop 3D Display with Triple Viewing Zones

“…To verify the feasibility of the proposed tabletop holographic display technology, a 3D model of a scorpion was built in the 3D computer graphic software 3Dmax. 16 images were taken in the same direction in accordance with the arrangement of the viewing angle of the metamaterial. These 16 images were then combined to one hybrid image and refreshed by the LCD panel.…”