LED screens are mostly flat displays which use Light Emitting Diodes for video display. There are several advantages with LED screens when compared to normal CRT screens. LED displays use less power and produce sharp colors when compared to other screen display techniques. With the help of LEDs it is possible to make huge screens at low cost. Have you even wondered how the bulky CRT monitors are replaced by thin and sleek LED screens in the present generation?
How LEDs work:-
The nature and color of light emitted depends on the nature of substances used in making LED’s. Any LED will contain two semi conductor materials with different valence shell configuration. When current is passed from LED, electrons gain energy and move from one semiconductor material to another material and come back to their original position. This process continues until current flow is present. While coming back to the original state, electrons release the energy they gained in the form of light. The semi conductor materials are chosen such that the energy gap between the two semiconductor materials is very less so that the electrons can move freely.
The nature of materials used will determine the energy band gap. This indirectly determines the energy required to excite electrons and move them from valence band to energy band. Energy required is directly proportional to the energy released by the electrons while coming back to their original state. The color is determined by the energy released as the energy release is in the form of photons and emits light. In general the color combinations of LED are determined by RGB and for Red color Gallium-aluminium arsenide (AlGaAs), for Green color Gallium phosphide (GaP) and for Blue color Silicium carbide (SiC) semiconductor materials are used.
In layman’s language, working of LED screens is simple. Each LED will have an anode and cathode which are connected to power supply. When current is passed through the circuit containing LED, LED emits light.
There are mainly two types LED screens available in the market now days i.e. Conventional LEDs and Surface Mounted LEDs. Conventional LED screens use discrete LEDs and this technique is used in making billboards, 7 segment display etc. whereas the SMDs or surface mounted LEDs are used to construct LED TV’s, screens of big theaters, LED monitors etc. Very big screens like Fremont Street Experience, Taipei Arena etc. are constructed based on SMD technology only. LEDs emit sufficient light so that one won’t feel any stress on eyes while watching LED screens. This is not the case with CRT displays or projectors. They emit very high or low light creating extra burden on eyes.
Companies are trying for new trends in the LED segment. Even electronic giants like Sony, LG are also winding up their CRT monitors and concentrating more on LED TVs, displays and monitors. OLED or Organic LED is the new LED technology that is currently used by electronic manufacturing companies. Sony XEL-1 is the world’s first OLED screen that is available for sale from 2009. It created a record as world’s thinnest screen (3mm) at the time of its production. With day by day progress in LED technology we can expect more records and even more sophisticated products.
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