Optical Properties of Liquid Crystals and LCD Displays

The liquid crystals are used in various consumer audiovisual devices among other office gadgets such as calculators, cell phones, digital cameras, watches, stereos, clocks, laptop computers and other personal organizers. The LCDs are also applied as instruments information display in automobiles speedometers, clocks and navigation aids. Nevertheless, there are a number of competing display technologies such as the light emitting diodes (LEDs), the plasma displays (PDs), and the organic light-emitting diodes.
Liquid crystal displays incorporate the unique properties of certain materials, nematic, selected smectic and cholesteric liquids. In certain liquid phases, the materials exhibit some electro-optic effects attributed to crystals. A typical liquid crystal display contains two electrodes or polarizer. A liquid crystal film material plugs the space between the two electrodes (Gu 2010, p. 6). Glass fibers are used as spacers that keep the thickness of the liquid crystals uniform within a range of 5µ to 10µ (Koide 2014, p. 86). The plates are also known as the polarizers, which are usually orientated at 900 to one another. The twisted phase commonly serves to reorient light that passes through the first plate, which consequently allows the transmission of the light through the second polarizer. When an electric field is applied to the liquid crystal layer, the molecular axes align parallel to the electric field and untwist. In such a state, light is not oriented making the polarized light from the first polarizer, which leads to loss of transparency with a further increase in voltage. This electric field property can be applied in making a pixel switch between the opaque and the transparent on command.