Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

In what way LEDtv differ from LCDtv?

Status
Not open for further replies.

sandy92

New Member
samsung and sony has introduced LED tv's.But led tv's have liquid crystal cells.I'm not understanding the fact
that how led's give brighter display than lcd.I don't think this is a senseless question.can any one help me.
 
It's probably just the same as a normal LCD but the backlight uses LEDs rather than fluorescent lamps.

Because LEDs are small enough to fit directly behind the LCD more light is transferred so it's more efficient.

There's probably also a way to adjust the current to the LEDs, depending on the brightness and colour of the image which probably boosts the efficiency further.

Don't confuse it with an OLED display which actually uses three LEDs for every pixel - red, green and blue.
 
No one has introduced 'LED' TV's - but they have introduced LCD TV's with LED backlighting instead of CCFL's.

Main advantage is the panel can be made thinner, making wall mouting even less obtrusive.

Some manufcaturers, notably Samsung, have been incorrectly advertising them as 'LED TV', and have been reprimanded by the Advertising Standards Agency.

CCFL backlighting is well tried and tested, and of proven reliability - there seems a fair amount of concern about the life span of the LED backlights, but it's too early yet for longterm results.
 
I thought the led tvs didn't require a back light, and that's why they where 40% more efficient.
 
hi,
i am new here, its nice to see that the very first minute of my membership i learned one more fact here.

i hope to stay on this forum for a while and learn lots.
 
This is true however Sony has a local dimming model. But as far as consumption is concerned the the local dimming LED backlit tv's are hogs. The contrast and lighting improvement is the caveat to the thicker size. My attraction is the sheer sleek thin total package, I don't care about tv picture quality as much as finding one that has lower operating costs. ;)
 
Last edited:
I would've thought local dimming would reduce the average power consumption, not increase it.
 
Well yesterday I learnt that LCD monitors now come with a led backlight and are slightly more expensive. I went into my local puter shop tonight and looked at a 23" led LCD an found it drew around 60 watts. The ccfl 19" LCD I bought only draws 25 watts. So much for led's using less current than ccfl in a LCD. Don't go saying as the led LCD has a bigger screen it uses more power as the psu supplied is the same on the smaller led LCD's too...
 
Well yesterday I learnt that LCD monitors now come with a led backlight and are slightly more expensive. I went into my local puter shop tonight and looked at a 23" led LCD an found it drew around 60 watts. The ccfl 19" LCD I bought only draws 25 watts. So much for led's using less current than ccfl in a LCD. Don't go saying as the led LCD has a bigger screen it uses more power as the psu supplied is the same on the smaller led LCD's too...

The PSU may be the same, but a larger screen will draw more power from it. Even just comparing CCFL screens, the bigger screen (fairly obviously) has bigger CCFL's, and may have more of them.
 
Don't forget that it's the screen area that counts so if you double the dimensions, the area and power required goes up by four.
 
No one has introduced 'LED' TV's.

Actually there is one, Sony - XEL-1 - 11" OLED TV. Only about $2000.

LG is just about to intro a 15" 15EL9500 in Europe for about 2000 euros. Said to have 10,000,000:1 contrast ratios and 0.001ms response times.
 
Last edited:
Hi there,

Another advantage of some of the LED tv's (LED's for back lighting of course) is the ability to dim in response to program information. The overall effect is a higher contrast, but also deeper blacks sort of like a CRT. The polarizers/twister modulation scheme used in LCD's dont allow for complete back light removal for dark passages, and that sure is annoying during very darkly lit video scenes. The ability to dim allows the modulation scheme to achieve a much darker black and that really helps if done right.
It becomes more apparent if you compare the dynamic range of the CRT to an LCD tv.
 
Another advantage of some of the LED tv's (LED's for back lighting of course) is the ability to dim in response to program information. The overall effect is a higher contrast, but also deeper blacks sort of like a CRT.

You mean EXACTLY the same as any remotely modern CCFL backlit LCD :p

Dynamic backlighting isn't anything new, or specific to LED LCD.
 
There is on major caveat to this whole thread.
LED billboards, some able to do full HD. I wouldn't call them TV's as not all of them are capable of full motion video but because of their size, LEDs are practical.

Just as a general consumer, I've noticed a LOT of variation in LCD TVs, dramatically so in quality and contrast even between various CFL based LCD TV's, the LED based LCD do seem to have better specs on paper, but some of the current CFL models are top notch in the video department. I wouldn't believe so much as one single piece of text on the quality of a large screen TV without actually viewing it with many other units for comparison. My brother in law does that, and I cringe when I have to go to his place and not say anything.


My wife and I are currently in the market for a 40" class HD TV but we're only generally browsing and we've gone to several local stores that have large numbers of displays near each other for comparison. I would NEVER buy something like that on paper only.
 
You mean EXACTLY the same as any remotely modern CCFL backlit LCD :p

Dynamic backlighting isn't anything new, or specific to LED LCD.

CCFL backlight does not respond fast enough to changes in overall scene to scene brightness, as result it is not very effective. It is used to get an overstated high contrast marketing specification. Some LED backlight TV's do sub-segment screen backlight modulation which is even more effective then a total screen LED backlight modulation in truely increasing contrast ratio.
 
RC, that statement about CCFLs not responding fast enough is a generalization, it would depend on the sophistication of the driver circuitry.
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top