What is Local Dimming LEDs?

LG was the first to push out this technology in India and today almost all major brands have Local Dimming (LD) in their flagship models. LD on Full array LED TVs give you the better picture quality compared to the LD on Edge-lit TVs, which was introduced this year in the Samsung UNC8000 series and LG LE5500 series. The LEDs used here are similar to the Full array models except that the array is broken into different zones and the LEDs in each zone can be dimmed or brightened depending on the scene at hand.
This gives you very good black levels that rival plasmas, since the LEDs in the dark areas can be completely turned off. There is a little catch here though. The side effect of this is a slight blooming effect noticed up close when a brighter image appears suddenly over a dark background. This happens because when displaying a dark background, the LEDs in that area are mostly off and when a bright object suddenly comes into that area, the LED’s light up to full brightness and then dim down to the current selected picture mode. This happens very quickly and isn’t very noticeable when watching a movie, but if you connect a PC to it with a static background, it’s visible.
Despite this, these TV’s are capable of delivering the best picture quality among LCD TVs.

Commercial true LED TVs don’t exist yet

How would one define a LED TV? It’s when a single LED is responsible for illuminating a single pixel on the screen, which is when you could do away with the LCD panel altogether. Today’s high-end LED LCD TVs pack in around 1500 LEDs and a typical full HD panel will have around 2 million pixels. So in order for a TV to be classified as a true LED TV, we would have to have 2 million LEDs powering individual pixels, which is simply not possible today, and probably won’t be commercially viable for some time.

So you see, no matter how companies try to spin and twist words and create fancy slogans, if a TV uses an LCD panel, it’s still an LCD TV and not a LED TV. Sony and LG clearly mention this on their site as LED LCD TV, but Samsung seem to have conveniently dropped the “LCD” from all of their LED TVs, which would easily fool the misinformed.

Aren’t LED backlit TV’s supposed to be cheap? 

Technically LEDs should be cheaper to produce compared to CCFL based LCDs, but our guess is that manufacturers seem to be cashing in on the hype and buzz generated by none other than them. Everybody wants a slimmer TV for easier installation, more bragging rights, etc. and we seemed to have conditioned ourselves into thinking the extra price is justified.

Another reason for LED LCDs being expensive could very well be the manufacturing process not being that mature as yet compared to LCDs.

It’s probably cheaper to manufacture an LCD, since this technology has been around for a while now and manufacturing units are more wide spread as compared to LED LCDs, which just started hitting selves a year back.

What the Future holds

In the next three to five years we should be able to see a considerable drop in prices as we adopt newer technology for cheaper and better LED LCD TVs. QD Vision is a company that claims to have developed a breakthrough technology called Quantum dots based on nano technology that is capable of delivering up to 40% more power efficiency and a color gamut over 100% of the NTSC spectrum. This is achievable due to the use of nano sized semiconductor crystals capable of emitting pure red, green and blue light.

You should see this technology hitting LED LCD models of 2011, which isn’t far away. If you were on the fence on getting an LED LCD TV then we’d say get the one with Local Dimming LEDs if you can afford it, or else simply stick with a cheaper LCD TV, as the color reproduction will be better than the “cheaper” Edge-lit models. Better still, if you have a well functioning CRT at home, stick with that and take the plunge maybe next year when prices go down south.


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