DYESTUFFS REPORTER

摘要

Majority of Guest-Host LCDs utilize the change in the light absorption by the pleochroic dye depending on the voltage applied. The intensity of the fluorescence can also be controlled in a similar way to absorption. The pleochroism of the dye results in maximum fluorescence intensity occurring by an alignment of the molecules, where the absorption is most intense.rnLiquid crystalline fluorescent dyes are used to improve the clarity of display. These dyes must not only fulfill the same requirements as that of conventional liquid crystal dyes but also exhibit a high fluorescence efficiency. Furthermore die position of the fluorescent band is very important and it should lie in the spectral region perceptible to human eye. liquid crystal display containing these dyes has been constructed and a strong contast on die fluorescent background achieved. The fluorescence arises from energy transfer between the host liquid crystal cyano biphenyl molecules and the dye. The stimulated host molecule transfers its energy to the dye molecule which emits in the 500-550nm range (green/yellow)