Host birefringence, displays

The impact of host birefringence and the number of helical turns on the contrast ratio of the display is illustrated in Fig. 19. The fact that these curves are nearly straight... 

Figure 6 shows the computed dependence of the display contrast ratio on the cell thickness for reJElective guest-host systems employing the three dyes mentioned above. The host system is assumed to have a birefringence of 0.26 (with nQ 1.50), corresponding to a phenylpyrimidine-type material.For these curves the cell thickness-to-pitch ratio (d/p), corresponding to the number of helical turns in the layer, is kept fixed at 3.0, which gives a constant critical voltage of about 5.4 volts when RO-TN-103 is. employed as a host (see Fig. 11) The dye...

The fullerene-binding abihties of CTVs have also been exploited in order to solubilize fullerenes, to immobilize them onto surfaces, and to incorporate them into liquid crystals. The hexa-substituted 12, for example, forms a liquid-crystalline phase. In the presence of C o, a 2 1 host/guest complex is formed, which also displays liquid-crystalline behavior, with a fluid birefringent phase at temperatures below 70 °C." The thio-derived CTV 13 forms self-assembled monolayers (SAMs) on gold surfaces." SAMs of 13 on modified gold beads can bind Ceo from solution when soaked in 1,2-dichIorobenzene solutions of Ceo-... 

Further, two thick rigid polarizing films spoil device flexibility to be unnecessary. Therefore, guest-host twisted liquid crystal devices with dichroic dyes [7] were fabricated to absorb the all-polarization-angle incident light. In this device, a nematic liquid crystal with low birefringence is introduced, and optical rotation effect is suppressed in the twisted liquid crystal layer. The contrast ratio of the display is inferior, but the guest-host nematic liquid crystal of twist orientation is suitable for simple text display. 

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