A backlight (or backlit) is a form of illumination that is used in LCD (liquid crystal display) screens. In other words, backlight is an internal source of white light that illuminated the LCD from the back of the display panel. This is how most modern laptop screens and desktop monitors are built. Note, LED-backlight LCD (or TFT) screen is not the same as an OLED (Organic LED) active screen which does not require a backlight to function.
Only a few years ago, display technology started incorporating LED (light emitting diode) backlights. Today LCD screens with LED backlight are still more expensive than traditional screens. Are they really better than old ones? Most computer experts would tell you that these new types of screens are brighter, thinner, less power-consuming (and less heat), and more reliable. They may forget to mention that these screens with LED backlight have longer life (old technology monitors starts dim after several years usage and loses brightness).
Also it is important that backlight-LED type of LCD screen is "greener" than a regular screen because it is mercury-free, less power-consuming, and able to prolong battery life in laptops (therefore, decrease its disposal problem). According to Dell's internal research, switching all of its laptops to LED, which use 43% less power than fluorescent lamp will save consumers $ 20 million dollars in energy costs and 220 million kilowatt-hours over 2010 and 2011.
There is one more reason to switch to LED backlight. Regular screens use CCFL (Cold Cathode Fluorescent Lamp) backlighting that produces inaccurate color. CCFL emits white light that has nonuniform (stripped) spectrum. Actual white light (sunlight or daylight) has a continuous spectrum. And LED is able to produce such full spectrum white light. That is why LED-backlight screens are able to reproduce more natural and richer colors. The first users who gratefully noticed this were photographers, designers, and graphics professionals.
Important to note, now we see only the first generation of LED backlight monitors. They are not developed and worked out properly yet. In principle, manufacturing LED is cheaper than CCFL and, historically, the monitors with LED backlit will be cheaper. Evidently, LED-backlight screen will replace soon older CCFL type as LCD replaced CRT in the past. However, it sees, the true revolution will come with OLEDs.
