5.4 Convertible 2D/3D Integral Imaging

A 2D display will for a long time remain an essential means of pictorial communication. Therefore the forthcoming 3D image technology has to be switchable to the 2D stage. As 2D is not feasible with a lenticular in front of the screen, the lenticulars necessary for 3D must be placed somewhere else, leading to a modified integral imaging approach. We encountered the lenticulars for integral imaging in Sections 5.1–5.3, while pinholes were introduced in Section 5.3.

We first investigate a 2D/3D approach in which a polymer-dispersed liquid crystal display (PDLC) is switched off for a 2D display and switched on for a 3D presentation [24–26]. Figure 5.30a and 5.30b shows the 2D and the 3D operations. A lenticular and a PDLC cell are placed behind the transmission LCD facing the viewer. In Figure 5.30a the light from a light source and a collimating lens is scattered in the PDLC cell (Chapter 2, ref. [3], p. 145), when no voltage is applied across the cell. This light illuminates first the lens array and then the pixels of the LCD with diffuse light from all directions. The LCD contains a regular 2D display which receives the diffuse light and represents the 2D image in the conventional way. The loading of a 2D image into the LCD has to be synchronized with the switching off of the PDLC.