LED v LCD? A tutorial on monitor options

17th October 2009
LED v LCD?  A tutorial on monitor options

To help readers  make sense of current LED and LCD monitor options, we  bring you a few useful resources:

What is LED TV?

(from http://ledtele.co.uk/ledvslcd.html )

The first thing to know about LED (Light Emitting Diode) TVs is that they are simply LCD TVs with a different kind of backlighting. The screen remains the same but LEDs are used in place of Cold Cathode Fluorescent Lamps (CCFL) that are found in most LCD TVs.
The LEDs can come in two forms, Dynamic RGB LEDs which are positioned behind the panel, or white Edge-LEDs positioned around the rim of the screen which use a special diffusion panel to spread the light evenly behind the screen.
RGB Dynamic LED TV This method of backlighting allows dimming to occur locally creating specific areas of darkness on the screen. This means you see truer blacks and much higher dynamic co ntrast ratios
Edge-LED TV This method of backlighting allows for LED TVs to become extremely thin. The light is diffused across the screen by a special panel which produces a superb uniform colour range across the screen.
Currently LEDs are not small enough to be used for individual pixels in domestic televisions, and so the use of true LED TVs is restricted to much larger screens in places such as sport stadia.
Don't let this put you off however, as there are some great benefits to choosing an LED TV over a standard LCD TV.
• Improved brightness and contrast levels, with deeper blacks.
• The use of Edge-LED lighting allows the TV to be thinner than standard LCD TVs.
• LED TVs can consume up to 40% less power than a LCD TV of similar size
• They can offer a wider colour gamut, especially when RGB-LED backlighting is used.
LED TVs are also more environmentally friendly due to there being no mercury used during manufacture. Overall there are many benefits to buying a LED TV rather than a standard LCD TV. A comparison between LED and LCD can be found here on the LED vs LCD page.

What’s so great about LED backlit displays?
(From: http://gizmodo.com/5271493/giz-explains-whats-so-great-about-led+backlit-lcds )

LED-backlit LCDs are where TV's future and present meet—they're the best LCDs you've ever seen, but they're not as stunning as OLED displays, which will one day dominate all. They're not cheap, but they're not ludicrous either. Most importantly, they're actually here.

With LCDs, it's all about the backlighting. This defines contrast, brightness and other performance metrics. When you watch plasma TVs, OLED TVs or even old tube TVs, there's light emanating from each pixel like it was a teeny tiny bulb. Not so with LCD—when you watch traditional LCD TV, you're basically staring at one big lightbulb with a gel screen in front of it.
The typical old-school LCD backlighting tech is CCFL—a cold cathode fluorescent lamp—which is an array of the same kind of lights that make people's lives miserable in offices around the world. The reason they aren't the greatest as backlights for TV watching is that they light up the whole damn display. Because LCD is just a massive screen of tiny doors that open and close, light inevitably leaks through the closed doors, when they're trying to show black, resulting in more of a glowy charcoal.

LEDs (light emitting diodes) are different from say, an old school incandescent bulb, which heats up a filament to generate light, in that they're electroluminescent—electricity passes through a semiconductor and the movement of the electrons just lights it up. Instead of having one lightbulb in the bottom of the screen, shining up through all of the LCD pixels, you can have arrays of LEDs that shine through smaller portions of the LCD screen, leaving other portions in the dark, so to speak.
OLED—"organic light emitting diode"—is slightly different. Since the electroluminescent component is organic and not a chip, each point of light can be much tinier. That's why an LED TV still needs the LCD screen in front: there's no way to have a single LED per pixel unless the screen is huge, and mounted to the side of a building in Times Square. OLEDs don't: HD OLED displays are made up of red, green and blue dots, no LCD panel required

LED TV and LCD TV: a comparison