Guest-host cells

Fig. 14. Angular dependence of the reflected light intensity in the plane of incidence from a MgO reflectance standard (thin line) and an internal reflector in a guest-host cell (heavy line). Collimated white light is incident to both samples at -45 . Arrows denote specular reflection from front surface of display cell.

Figure 23. Threshold characteristic of a positive mode guest-host cell using a negative dielectric host and homeotropic alignment. (After Scheffer [13]).

The electrode surfaces of a normal LCD sandwich cell d 8-10 pm) are coated with an alignment layer in order to induce a planar alignment of a host (chiral) nematic mixture containing the dichroic dye of positive dichroism and a chiral dopant. Due to the absence of polarisers a very thin mirror can be incorporated within the cell on top of the rear glass plate electrode in direct contact with the guest-host mixture, see Figure 3.15. 

The static homeotropically aligned guest-host nematic mixture (plus guest dye and chiral dopant) is optically transparent and, therefore, the display appears colourless in the non-activated state. The lower limit of the pitch for a given cell gap, before a twisted nematic structure becomes energetically more favoured than the homeotropic nematic structure, is determined by the djp ratio ... 

Quinone Compound, Liquid Crystal Composition, and Guest-Host-Type Liquid Crystal Cell Employing the Same T. Katoh, US Patent 6,703,084 (March 9, 2004)... 

The host guest stoicheiometry, cell constants, and packing motifs of DCA complexes... 

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