For sake of clarity:
We are facing two different LED technologies today:
1. Direct LED
Here the backlight consists of hundreds of small LED's (usually white) which are divided into segments. The segments are referred to as a number of rows and columns.
The LEDs are positioned directly behind the screen, over the entire surface of the screen. Doing so, you can locally switch ON, OFF or dim a segment where it is needed.
This dimming, if done well by the TV manufacturer, enables the fabulous black levels in dark scenes or areas.
The more segments, the more precise the dimming can be done and the less light leakage you will observe.
2. Side-Lit LED
Here the backlight consists also out of LED's, but in this case they are positioned not behind the screen, but on the sides of the screen.
This has 2 big drawbacks:
- You can not locally dim a segment where it is needed
- If you look well, you will see that there is some light leakage at the sides of the display where the LED's are located.
The second point may be improved by suppliers and may depend on sample/size.
However, the first point is a definite drawback of the technology and puts the TV in performance comparable to it's CCFL brother. The whole problem is that the backlight is dimmed all over the screen in the same ratio.
The blacks will look either washed-out because of light-leakage OR the light output in dark scenes will be dramatically low, due to dimming algorithms.
Theoretically, you could also dim in rows or columns, but never in segments.
This would not bring back the performance of direct LED backlight sets.
So what is the advantage then? Well: the side-lit LED panels can be made very very thin and they consume less power than a CCFL TV. That's it.
Be aware of this when buying a TV: a LED tv does not mean you ar buying a top PQ tv!
We are facing two different LED technologies today:
1. Direct LED
Here the backlight consists of hundreds of small LED's (usually white) which are divided into segments. The segments are referred to as a number of rows and columns.
The LEDs are positioned directly behind the screen, over the entire surface of the screen. Doing so, you can locally switch ON, OFF or dim a segment where it is needed.
This dimming, if done well by the TV manufacturer, enables the fabulous black levels in dark scenes or areas.
The more segments, the more precise the dimming can be done and the less light leakage you will observe.
2. Side-Lit LED
Here the backlight consists also out of LED's, but in this case they are positioned not behind the screen, but on the sides of the screen.
This has 2 big drawbacks:
- You can not locally dim a segment where it is needed
- If you look well, you will see that there is some light leakage at the sides of the display where the LED's are located.
The second point may be improved by suppliers and may depend on sample/size.
However, the first point is a definite drawback of the technology and puts the TV in performance comparable to it's CCFL brother. The whole problem is that the backlight is dimmed all over the screen in the same ratio.
The blacks will look either washed-out because of light-leakage OR the light output in dark scenes will be dramatically low, due to dimming algorithms.
Theoretically, you could also dim in rows or columns, but never in segments.
This would not bring back the performance of direct LED backlight sets.
So what is the advantage then? Well: the side-lit LED panels can be made very very thin and they consume less power than a CCFL TV. That's it.
Be aware of this when buying a TV: a LED tv does not mean you ar buying a top PQ tv!