“LCD, LED & CRT”
LCD
COMPOSITION
A liquid-crystal display (LCD) is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals. Liquid crystals do not emit light directly.
LCDs are available to display arbitrary images (as in a general-purpose computer display) or fixed images which can be displayed or hidden, such as preset words, digits, and 7-segment displays as in a digital clock. They use the same basic technology, except that arbitrary images are made up of a large number of small pixels, while other displays have larger elements.
The LCD screen is more energy efficient and can be disposed of more safely than a CRT.
The inside of an LCD monitor basically comprises of 3 units:
1. LCD panel (the screen)
2. Backlight (a CCFL or cold cathode fluorescent light bulb)
3. Inverter (power supply unit)
PROPERTIES
Liquid Crystal Properties And Notebooks LCD Screens
Liquid crystals are interesting because they don't exactly fall under the three main states of matter: solid, liquid or gas. Liquid crystals are actually in an intermediate phase between crystalline solid and isotropic liquid. Discovered in 1888 by Friedrich Reinitzer, an Austrian botanist, liquid crystals are widely used in electronic displays.
Displays, such as notebook screens, use the fluidity and anisotropy (property of being directly dependent) of the liquid crystals. The anisotropy causes the dielectric constant and refractive index to vary on the orientation of its molecules.
Nematic, Smectic and Isotropic properties
One of the more common liquid crystal phases in the nematic phase. The nematic phase of liquid crystals is what makes LCD screens possible. During this phase, the molecules are in no positional order, but do have a notable pattern. This may cause the molecules to flow and their center of mass may shift randomly and distributed as