## 3 Experiments and Results  
### Verification of Switchable Color Filter Array Assembled with a Large Area Color Display  
The display design of an autostereoscopic screen with a switchable wavelength-selective parallax-barrier was set up by commercially available display components. It was experimentally examined how the theoretical approach corresponds to the practical behavior.  
Figure 6: Multiview mode with special color filter scheme by using nine views and three switching stages (at the times \(t_{1}\), \(t_{2}\), \(t_{3}\)); on the **left side** is illustrated the color filters and on the **right side** the corresponding interleaving pattern.  
Figure 7: Luminance profiles for the nine views of the multiview display design.  
The double-display mock-up is based on two different flat screens and is shown in Figure 8. Resolution data and pixel pitches of the display are listed in Table 1. In reference to the chosen display design, continuous RGB-color lines are arranged by 90\({}^{\circ}\)-twisting of the rear Display 1. The interspace distance between both displays can be aligned by micrometer screws at four positions. For the investigations, the distance \(a\) between display and barrier is set to 2.9 mm. This display combination shows a central-perspective emission characteristic as needed for multiview technologies. Both displays use nematic crystals and in-plane-switching technology with a 1:3 aspect ratio of pixel shape. The opposite arranged polarizers of the displays are aligned in the same direction. The 3D display arrangement in operation shows visible moire-formation caused by the overlapping of two periodical grids and the high area share in subpixel gap lines. To suppress those effects, the usage of elliptical diffusors was examined. However, the reduction of moire-effects by diffusion affects the image contrast.  
The measured luminance losses of the system (see Table 2) are approximately 91% and are caused by the geometric properties of the display pixels and by the spectral properties of the arrangement. The question is how this value can be improved. Therefore, we have to understand the conditions that reduce this value.  
Figure 9 shows the geometric differences between the idealized and real apertures of the pixel designs, in Figure 9a for the image display and in Figure 9b for the color barriers.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Spectral Luminance** & **Display 1 (5 K)** & **Display 2 (1.4 K) \({}^{*}\)** & **Demonstrator, Displays 1 + 2** \\ \hline White Pixel Luminance & 214 cd/m\({}^{2}\) & 158 cd/m\({}^{2}\) & 18.6 cd/m\({}^{2}\) \\ Red Pixel Luminance & 56 cd/m\({}^{2}\) & 32 cd/m\({}^{2}\) & 5.3 cd/m\({}^{2}\) \\ Green Pixel Luminance & 146 cd/m\({}^{2}\) & 109 cd/m\({}^{2}\) & 9.8 cd/m\({}^{2}\) \\ Blue Pixel Luminance & 12 cd/m\({}^{2}\) & 17 cd/m\({}^{2}\) & 0.9 cd/m\({}^{2}\) \\ \hline \end{tabular} \({}^{*}\) Values measured with the display backlight (the backlight was removed in the mock-up assembly).  
\end{table}
Table 2: Luminance of single displays and the demonstrator with white and prime-color (red, green and blue).  
Figure 8: Demonstrator, with 90\({}^{\circ}\) crossed display panel, mounted to a metal frame with calibration fixtures. (**a**) frontal view and (**b**) lateral view with details.  
Due to the non-transparent gaps between the pixels, the light intensity emitted by the subpixels will be reduced by approximately 1/3. The idealized gap structure was simulated by the in-house software; the luminance profiles in Figure 5 were calculated based on this model. Furthermore, the crossed arrangement of displays and the proportion of pixels cause an additional 2/3 reduction of the light intensity. The geometrical reduction factor results in approximately 2/9 or 22% transmission of the source intensity of Display 1.