lights emitted from one part of an ele-mental image are integrated by the corresponding micro-lens toreconstruct orthoscopic 3D images, while lights emitted from theother part of the elemental image are modulated by adjacent micro-lenses to present flipping images, as shown in Fig. 1. The former isthe useful zone in Fig. 1, while the latter is the useless zone in Fig. 1.The number of the useful zones in horizontal direction is equal tothat of the micro-lenses in horizontal direction, and the numberof the non-display zones in horizontal direction is one less thanthat of the micro-lenses in horizontal direction. The numbers ofthe useful and useless zones have no reference to the viewing dis-tance. When the viewing distance increases, the horizontal widthof a useful zone is increased, while the horizontal width of a use-less zone is decreased, vice verse. At a suitable viewing distance,the horizontal width of a useless zone is twice as much as that ofa useful zone and the useless zones can be replaced by two sets ofuseful zones in two other II 3D displays. Therefore, two orthoscopic3D images that are integrated in two other II 3D displays can alsobe presented in the flipping zones in Fig. 1, respectively.