We investigate the impact of the deposition of low work function metals such as calcium on thin layers of fluorene-type polymers by time-of-flight secondary ion mass spectroscopy. An implantation process rather than a slow metal diffusion is found to be the most probable source of metal contamination within the polymer layers. This contamination extends to a range of several tens of nanometers in the organic layers. Photoluminescence and electroluminescence measurements are performed with varying calcium layer thicknesses. The luminescence efficiency exhibits a strong correlation with the depth profile of the calcium present within the polymer. The results are discussed with respect to the exciton diffusion length in the fluorene polymer. A numerical model including exciton formation, migration, and quenching is proposed in order to describe the observed phenomena.

Complete suppression of color shift in in-plane switching mode liquid crystal displays (LCDs) has been realized. The LCDs have a multidomain structure obtained by unidirectional rubbing and use of zigzag electrodes. The design concept and performance of the devices are described in this paper.

Color shift and gray scale reversal for very large viewing angles are analyzed theoretically for in-plane switching. It follows that the color shift depends on the change of the effective birefringence dΔn, whereas gray scale reversal depends on the effective angle between the polarizers and the liquid-crystal director angle. Experimental results confirmed the theory that small gray levels result in a larger color shift. Likewise, the viewing angles in which a gray scale reversal occurs, correlate with the theory. To counter these drawbacks, two multidomain structures are proposed, neither of which requires additional orientation processes. With these multidomain structures, color shift was suppressed and no gray scale reversal was observed. However, the multidomain structures reduce maximum transmission, the extent of which depends on the type and design of the structure.

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Recent progress in liquid crystal displays(LCDs) achieved by photo-aligning the liquid crystal (LC) with the linear photopolymerization (LPP)-technology are outlined. LPP-alignment gives way to high resolution azimuthal LC-director patterns with defined bias tilt angles, which renders multidomain twisted nematic (TN-) LCDs feasible. A 5 inch 320x240 pixel LPP-photoaligned dual domain TFT-TN-LCD for car navigation systems exhibiting a very broad angle of view is presented .