Fig. 1. Research on glasses-free 3D display based on parallax barrier

Fig. 2. Research on glasses-free 3D display based on lenticular lens

Fig. 3. Directional backlight 3D display system

Fig. 4. Researches on 3D display based on integrated imaging

Fig. 5. (a) Schematic of dual LCD display; (b)，(c) Structure of a multilayer LCD display system based on the attenuation layers; (d)，(e) Structure of a multilayer LCD display system based on polarization layers

Fig. 6. (a) 3D display research proposed by D. Fattal et al; (b) Schematic of multi-view modulation; (c) 3D display effect diagram^[71]; (d) Vector light field display based on pixel-based metagrating proposed by Wan et al^[72]; (e) 3D images based on vector light field display

Fig. 7. Schematic of the vector light field 3D display based on metagratings; (a) Schematic of the wavefront reconstructed by hologram; (b) Schematic of multiview 3D displays based on periodic structures; (c) Schematic of holographic sampling displays based on metagratings; (d) Schematic of the full-color video rate 3D displays by combining a LCD, color filters and the metagratings; (e) Schematic of the metagratings combining emitted beams to form a color pixel

Fig. 8. (a) Schematic of vergence and accommodation conflict; (b) Schematic of super multi-view 3D display

Fig. 9. Holographic sampling 3D display with a continuous 3D lightfield; (a)Schematic of recording process of a 3D scene by a digital camera; (b)-(e) Captured photos at different depth from a holographic sampling 3D display

Table 1. Advantages and disadvantages of current autostereoscopic 3D technologies