Monitors,LCD & LED

PRESENTED BY RAMEESHA SADAQAT

ContentsDefinitionHistoryStructureDiagramDifferences

Monitor A display screen that provides a visual output. Monitors are very important because without them we

wouldn’t be able to see and do anything.

History VDT and terminals monitors introduced in 1980’s. They

only displayed text in two colors usually black and green. In 1981, IBM introduced the CRT monitors which could

display 16 colors. XGA and UXGA introduced in 1987 can display up to 16

million colors. In 1990’s LCD monitors were introduced.

LCD(liquid crystal display)

LCD’s are super thin displays that are used in laptops, computer screens and flat panel monitors.

LCD screens are based on the principle of blocking light (rather than emitting it), they use up much less power than standard CRT (Cathode-Ray Tube) monitors.

Structure 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)

The internal hardware of an LCD monitor is structured in such a way that the inverter supplies power to the backlight bulb, which in turn lights up the image you see on the LCD screen.

There are other components as well -- like the transformer, analog/digital converter and external DVI/VGA ports -- but the above 3 are the main components

Diagram

LED(light emitting diode)

An LED is an electronic device that emits light when an electrical current is passed through it.

Early LEDs produced only red light, but modern LEDs can produce several different colors, including red, green, and blue (RGB) light. Recent advances in LED technology have made it possible for LEDs to produce white light as well.

Structure LED display is made up of two parts: Main LED panel which is composed by several LED display

units(Led cabinet or LED panel)that can connected together. This part is the main body of the LED display.

Another part is the controller. The controller can also be divided into two parts:

Control board( hardware) Control system( software).

Diagram

Difference b\w LCD & LED

LCD LCD displays are not self-illuminating. They need a backlight in order to

produce a visible picture. Regular LCDs are backlit by CCFLs

(Cold Cathode Florescent Lamps). These lights resemble the florescent

light tubes used for lighting, and are arranged in horizontal rows behind the LCD screen.

LED An LED TV still uses an LCD display, but

instead of CCFLs, it is illuminated using an array of LED lights.

LED lights are smaller and thinner than CCFLs, an LED monitor can be thinner and more lightweight than an LCD monitor that uses CCFLs.

LED lights are also more energy efficient than CCFL lights, and perform better as well.

LED lights are only illuminating when they need to be, so contrast and black levels on an LED monitor are usually superior to those found on an LCD display that uses CCFL lights.

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