Why do LED TVs and monitors have a backlight setting?

[Masque]

My old Sanyo LED TV has a setting to adjust backlight, but I've always been told that LEDs, unlike LCDs, produce their own light. Shouldn't the backlights (edge, direct, etc) be unnecessary?

Also a question about this monitor at Amazon: why the price difference between the white one and the black one? White: $309.00, Black: $499.00

https://www.amazon.com/Deco-Gear-Curved-Ultrawide-Monitor/dp/B0CNBRW7GQ?th=1

The only difference in the spec sheet I can find are these:

Contrast ratio for white is 3000:1 and for black is 4000:1
Display technology for white says "LED" and for black says "E-LED".

Further research got me to my initial question as it appears E-LED refers to the edge-mounted backlights in a monitor or TV as opposed to direct backlights (behind the pixels).

The only guess I have for the second question is the white monitor just isn't selling well?

Background: A couple of days bought, tried, then returned an LCD Samsung UWQHD (3440 x 1440) and didn't mind (or even detect any problems with) the LCD display, coming from LED, but I can't find a suitable 39-40" LCD non-ultrawide. The Samsung was 34", same width as my 40" but felt like I was looking through the rear window of a 71 Stingray, as if I was missing a lot of vertical dimension, so now I want a monitor the same size (and aspect ratio) of my TV but 1440.

[SimicEngineer]

Most displays marketed as "LED" just have a LED backlight instead of CCFL, with the actual pixels still being some type of LCD. Panel types that use LED-based pixels include "OLED', "WOLED", "QD-OLED", and "MicroLED".

[Masque]

Well that's devious. If it's LCD why are they allowed to be called LED?

There should be a law. Standards.

[Illusion of Progress]

It was mostly for marketing, as LED backlit LCDs were able to be thinner, brighter, and use less power (and thus also create less heat), so they wanted to make them stand out around the early 2010s when they started becoming common.

They still use LEDs (just for the backlights instead of the pixels) so mentioning LED was never breaking a formal law. Misleading though for those who interpreted them as LED pixel displays, yes. But the displays weren't proclaiming they were that, either.

That's the thing; when standards don't exist, companies do this all the time when they can.

nVidia's GT 1030 comes to mind.

AMD's "8 core" FX CPUs come to mind. What makes a "core" a "core" still doesn't have a formal definition, because... well, that'd be hard. And often times, regulatory standards can backfire. Maybe later, they make some change to a "core" that isn't bad but makes it no longer a core, so then what? How do they define they CPUs? new terms? And then those need standards and regulation? What a core is still isn't defined as far as I know. AMD actually just decided to settle on that instead of continue to fight it.

There's an endless list of further examples of this stuff.

[r.linder]

LED displays are just a specific type of LCD display... The difference is that older LCD displays used CCFLs (cold cathode fluorescent lamps) to provide lighting while all modern displays use LEDs to provide lighting. They're technically LED-LCDs and not LCDs anymore.

The differences:
Older displays using CCFL lighting had cold cathode lamps sitting across the inside of the display to evenly provide illumination with similar brightness levels across the whole screen. The downside is that the TVs were much thicker and the picture quality wasn't as great due to less control compared to LED technology.

Many LED TVs have full-array backlighting which can be lit or dimmed per zone, aka local dimming. Full backlighting arrays allow for precise control because of features like local dimming which results in a more vibrant and well balanced image with color and contrast as parts of the image that should be bright will be while parts of the image that should be darker will be darker with good applications of local dimming.

Mini-LED lighting is a somewhat newer concept which involves much smaller LEDs to improve upon full-array backlighting as you can fit more LEDs per zone, this technology is making its way into gaming monitors as well and the results have been pretty good. But all of these kinds of LED displays tend to be more expensive.

Edge lighting is another form of LED lighting for LED displays which just have LEDs along the edges of the screen in different possible configurations, picture quality isn't as good as full-array backlit screens but still better than CCFLs, and despite the drawbacks of edge lighting, TV makers have been able to make it look really good and more comparable to full-array backlighting while still being cheaper.

The difference between LED and OLED, is that they use different technology altogether, as OLED displays use panels of pixel-sized organic compounds which react to electricity, and since each tiny pixel can be turned on or off individually, OLED displays are self-emissive; they don't need or use any kind of backlighting LEDs at all.
This allows them to have incredible contrast levels, better pixel accuracy, and allows the entire display to be very thin compared to standard LED displays. Some OLED type displays can be as little as a few mm thick.

QLED displays use LEDs, but they use quantum dots to give an additional boost to color saturation and brightness. With features like local dimming on top of that, QLED can be just about as impressive as OLED.

QD-OLED displays combine QLED with an LCD matrix with a color filter to produce vibrant pictures with great color and contrast detail similar to an OLED.


Basically all of this can be found with a quick google search. They're allowed to use these terms because it's not really misleading, you just have to do your research to know what the differences are.

[Tonepoet]

I mean the others basically covered it.

It is worth There are micro-L.E.D. displays that use L.E.Ds. as the pixels, but those largely only exist as prototypes that are maybe shown off at trade shows. When they come to market I anticipate the first televisions costing at least five digits and maybe they'll jump down to $2,000 or so in a generation or two, based on O.L.E.D. pricing history.

LED displays are just a specific type of LCD display... The difference is that older LCD displays used CCFLs (cold cathode fluorescent lamps) to provide lighting while all modern displays use LEDs to provide lighting. They're technically LED-LCDs and not LCDs anymore.

If we're being technical they're still Liquid Crystal Displays regardless of if they're backlit by a C.C.F.L., an L.E.D. or a candle stick, and thus merit the L.C.D. abbreviation. >_> You can specify C.C.F.L. or L.E.D. L.C.D. if you need to be clearer regarding what type of back light is used.

[_I_]

led/lcd tvs are led backlit
edge lit is still backlit, as the light comes through the diffuser panels from the side
makes them thinner, but less evenly lit, and they cannot be zoned

its oled that are all leds for each subpixel

[Masque]

Thanks for the education. I knew this was the right place to ask.

Edit: r.linder, I *did* a quick Bing search -- read quite a few sites for an hour or so, but still got better answers here.

[r.linder]

At this point if you have the money, get OLED, just be wary that OLED screens are prone to burn-in so make use of screensavers or sleep settings to preserve its full day one quality

For non-OLED, mini-LED and QLED based displays are as good as it gets for visual quality

[Masque]

I've read (only today, and only - as I noted in my edit, for an hour or so) that OLED, being "organic", will decay and die inside a few years, while LCDs can last literally decades with zero degradation.

Also for the past year I've read -- taken with a grain of salt -- in many places that LEDs -- not just in our screen devices, but in every lightbulb in our homes (every lightbulb in my house is LED) -- are causing macular degeneration, and this will become an epidemic, and well known, in about 10 more years, as opthomologists are overwhelmed with new patients. Of course, I'm predicting if this does come to pass, the press will say that doctors and The Science are "baffled" and the reasons will be anything *but* LEDs.

[r.linder]

Masque님이 먼저 게시:

I've read (only today, and only - as I noted in my edit, for an hour or so) that OLED, being "organic", will decay and die inside a few years, while LCDs can last literally decades with zero degradation.

Also for the past year I've read -- taken with a grain of salt -- in many places that LEDs -- not just in our screen devices, but in every lightbulb in our homes (every lightbulb in my house is LED) -- are causing macular degeneration, and this will become an epidemic, and well known, in about 10 more years, as opthomologists are overwhelmed with new patients. Of course, I'm predicting if this does come to pass, the press will say that doctors and The Science are "baffled" and the reasons will be anything *but* LEDs.

OLEDs degrade pretty easily, simply leaving the same static image on the screen for long periods of time will result in burn-in

Manufacturers can try to prevent this in various ways but it's a key characteristic of the technology

[Masque]

Tonepoet님이 먼저 게시:

If we're being technical they're still Liquid Crystal Displays regardless of if they're backlit by a C.C.F.L., an L.E.D. or a candle stick, and thus merit the L.C.D. abbreviation. >_> You can specify C.C.F.L. or L.E.D. L.C.D. if you need to be clearer regarding what type of back light is used.

Indeed it seems some companies are more honest than others, as the Samsung I just returned was clearly labeled "LCD" on the packaging and advertising. See under "Display Type" pulldown on this Amazon page: LCD.

https://www.amazon.com/SAMSUNG-ViewFinity-Ultra-WQHD-Borderless-LS34C502GANXZA/dp/B0C1KPXPM9/