LCD v LED tv?

seligehgit

My mate is thinking of buying a new flatscreen tv?Any advice re which of the above types is superior?He wants to buy a Sony model if possible.I understand that the main difference relates to the backlight.Another techno mate has said that the older LCD types have less problems than the new LED models(some teething problems!).Apologies if this is'nt the correct forum,unsure where to post.
Selig

watty

They are all LCD.

The LED backlight is thinner than the CFL backlight. That's the only difference. Cheaper LED backlit LCDs are actually poorer than CFL backlit.

All LCD panels have improved.

There are real LED screens. They are usually 72" to 200" or larger!

OLED is only small and not "true" LEDs in same sense as LED backlights, LED panels or LED torches.

JDxtra

The only reason I see to opt. for LED is if you are going to wall mount it and you want it really, really flat. Otherwise, LCD is cheaper.

implausible

A guy in a shop told me all TVs were going to be LED in the future - any truth to this? I'm thinking of buying a Sony, but I like my tvs to die of exhaustion after a decade:cool:

John mac

did he also say plasma screens have to be re-gassed every 5 years?:rolleyes:

implausible

John mac wrote: »

did he also say plasma screens have to be re-gassed every 5 years?:rolleyes:

LOL. I'll take that as a 'no' then!

watty

My laptop LCD gets more use every day than an average TV. It's CFL backlight is now a bit substandard. It's 9 years old

Some CRTs lasted only 2 years (some WS Philips were poor). Some CRTS from late 1930s inc a couple from 1936 still going in TVs.

The CFL backlights gradually get dimmer with hours used. BUT SO DO THE LEDS! Hardly any LED backlit LCD TVs use true Red, Green and Blue LEDs (Blue have shorter life than Red or Green). They are usually violet/UV LEDs with phosphor to make a suitable light, so are not much different in life and degradation of brightness to CFL backlight. The ONLY advantage is it's thinner.

Real RGB instead of "white" LED back light for LCD are 3 to 4 times the price of regular LED lit LCDs.

Please don't call them LED TVs. There ARE real LED screens. But not in regular shops. They are all LED backlit LCDs.

Pangea

I bought an LCD last year, I didn't bother with the LED, it was dearer and the TV guy said a LED might be very bright in a bedroom etc.
The LED looks nice and slim though.
I suggest you read this.
http://www.avforums.com/forums/lcd-led-lcd-tvs/1149434-led-televisions-information-about-fantastic-radically-new-technology.html

seligehgit

Thanks a mill for all the advice guys,much appreciated.

implausible

Pangea wrote: »

I suggest you read this.
http://www.avforums.com/forums/lcd-led-lcd-tvs/1149434-led-televisions-information-about-fantastic-radically-new-technology.html

Great link Pangea, v interesting to read that Samsung got their knuckles rapped. Thanks.

watty

Yes, the very very skinny LED edge lit LCDs have two issues:

More uneven than cheaper CFL backlit LCD (or more expensive fatter full LED backlit LCD)

Very poor tinny sound. No space for speakers.

Charisteas

Is there any significant difference in electricity consumption between LCD and LED branded TV's?

I got my eye on a Saorview approved Walker TV, the LED version is more expensive but if it's saving a tidy amount in electricity, then I don't mind paying that bit extra.

watty

No there isn't.

Either way nearly 3/4 of the light is stopped by the LCD. CFL are actually similar efficiency (or even slightly better!) as "white" LEDs.

A modern CRT at same brightness and screen size can actually use less electricity.

The bigger and brighter it is the more it uses. Turn back light down to about 60% to make it last x5 longer and save electricity. Avoid sunlight. Direct sunlight will actually fade the colour of the LCD!

lucernarian

When I was reading about LED backlit laptop screens about 4 years ago, one of the biggest advantages I saw cited was a reduction in power usage of 20% compared to CCFL backlights. I'm not sure if the typical flatscreen LCD tv uses CFLs as in office lighting or if they only use the cold cathode type. I think typical CFLs are even more inefficient again than the CCLF type.

That would be an advantage of LED backlights in addition to the thickness reduction.

Edit: after digging around at further sources, typical FLs are more efficient, particularly compared to a short cold cathode fluorescent light. They have better power density (light output for a given volume of tube) anyway, as do the backlight LEDs in use for LCD screens.

ted1

Leds tend to be brighter than lcds. Asides from they are the same

watty

ted1 wrote: »

Leds tend to be brighter than lcds. Asides from they are the same

Generally not true.

In fact LED edge lit LCD screens are not as bright. Very expensive true R, G, & B LED full backlight are brighter.


They are ALL LCDs. but there are FOUR kinds of lighting

CFL (cold cathode only on old pocket LCD TV, too dim, not efficient enough)
Edge lit with "white" LEDs (more expensive)
Fully backlit with "white" LEDs (much more expensive)
Fully backlit with true Red, Green and Blue LEDs (very very expensive)

There is actually no such thing as a White LED. They are violet to UV LEDs with shorter life than CFL or Red/Green/Blue LEDs and use a mix of phosphor coating to get White. A bit like CFL (which are miniature Florescent tubes).

The only advantage at all is a skinnier display. Everything else is a myth.

Please stop calling LED edge or back lit LCDs "LED" screens. There are real LED screens. These are ALL LCDs.

implausible

watty wrote: »

The only advantage at all is a skinnier display. Everything else is a myth.

Please stop calling LED edge or back lit LCDs "LED" screens. There are real LED screens. These are ALL LCDs.

You'd need to tell that to all the websites that get you to click either LCD or LED when trying to chose a TV. It's made out to be a whole different type of TV!

ted1

The only real true led tvs are the giant ones they have at stadiums

Moon54

I just skimmed the thread, but I believe an LED TV is preferable over LCD.

IMO LED TV have several advantages;
* less power comsumption
* less heat generated, compared to LCD
* longer lifespan, in theory
* skinnier display

watty

Your 1st 3 points are largely mythical for identical brightness, except for the very high end very high cost RGB LED backlights with light pipes.

Also the actual LCD screen is identical on both models.

Life span is no longer except on high end RGB LED backlit LCDs.

A true LED TV is lower power consumption, about 1/2 to 1/3rd for same size and brightness. But the TVs you mean are LED edge or rear backlit LCD TVs. There are ZERO domestic LED TVs on sale. Only large Professional & Commercial auditorium LED TVs exist. Or very small OLED.

mossym

watty wrote: »

Or very small OLED.

which harks back to the pointan earlier poster made about all tv's being LED(sorry watty, LED backlit LCD's)

a google search will show you how much money samsung and LG have invested in OLED development, including large screen displays(which can be made, just not quick enough for large volume production)

if any tv type is going to dominate in the future, it will be OLED, not led backlit LCD

watty

Certainly the OLED (which has more in common with Organic Electroluminescent panel than real LED) is more likely than true R G and B LEDs, those LED displays have never been successfully made as integrated panels but are 500,000 to 9 million discrete LEDs. Hence large and expensive. The OLEDs are actually all "printed" simultaneously on a single substrate with then suitable phosphors and/or filters printed. OLED panels tend to be either yellow/Violet emitters with phosphors to get Red, Green and Blue, or phosphor to get "white" and then R G B filters like LCDs. There are also true Red, Green and blue emission OLED, but till recently the blue was short lived.

Modern Plasma plasma panels solved the ageing problem by hiding it. They are designed at higher brightness and then limited to half brightness or less. The panel power is then automatically turned up as the panel ages, thus giving an apparent x2 to x3 lifetime and more consistent performance.

BTW. LCD can be "burnt in" just like CRT or Plasma. By static image or sunlight, The dye in the RGB filter stripes gets faded. It just takes longer. You should see screens in call centre!

Sony did make a very very expensive LCD with light pipes fed by R, G & B LED arrays at rear to give better colour and minimise LCD filter fading. Almost all the LED backlit LCDs are "white" LED backlight. RGB LEDs is x4 price screen.

LCD panel itself is actually monochrome and colour created by having R, G and B stripes with thus 1920x 3 LCD pixels horizontally. So total pixels is 6,220,800 on full resolution panel.



However to increase brightness and reduce pixel count some phone displays a while ago switched to
R G
G B
layout.
It gives 30% more brightness.
Colour information is spread over 2 lines so only 4,147,200 pixels is needed.
In fact if you do subpixel anti-aliasing horizontally too then only 2,073,600 LCD pixels needed. So "true" computer RGB resolution is only 960 x 540, but apparent sharpness is 1920x 1080 as the eye is much less good at colour than monochrome. Also DVD, Blueray, DivX, Xvid, Analogue TV, DV camera, MPEG, DVB (Cable, satellite, terrestrial) all use much less colour resolution than mono-resolution

http://en.wikipedia.org/wiki/Chroma_subsampling

So a more modern "full HD" LED or CFL or CCFL backlit or edgelit LCD may be 1/4 of the pixels of an older model, but actually look just as sharp without a magnifying glass. Doing this trick does give over 30% more brightness than "traditional" LCD (LED backlit or not).

See how Clear type works to understand how
R G
G B
at 960 x 540 "overall pixels" can give effective 1920x1080
http://en.wikipedia.org/wiki/ClearType
and also http://en.wikipedia.org/wiki/Subpixel_rendering

The models with yellow also are actually less accurate colour but a bit brighter and more vivid looking as yellow + blue is nearly white.