edge-lit lcd panel price
LED-backlit LCD, which uses light-emitting diodes for backlighting is a common type of display on televisions and laptops. Unlike pure LED screens these LCDs are not self-illuminating and are reliant on the backlighting for illuminating the display. It is an advancement on the preceding cold cathode fluorescent technology and some manufacturers and retailers may advertise this type of screen as an LED TV.
Edge-lit is a type of screen backlighting that has LED lights lining either the top and bottom edges of the screen or the perimeter of the screen. This form of backlighting differs from others as the screen is not lit from behind, and often produces a more muted effect. An opaque piece of plastic called a diffuser light guide distributes the lighting across the rear of an LCD panel.
Edge-lit LEDs can be individually brightened or dimmed to provide the high degree of backlight control that screened content demands. Edge-lit screens can achieve this in one of two ways:
Direct-lit backlighting uses LED lighting across a television back panel. This form of backlighting initially used Cold Cathode Fluorescent Lamps (CCFLs) before transitioning to LED. The lighting is behind the LCD panel to provide consistent lighting across the entire screen.
Both types of backlighting provide the illumination LED screens required to produce a visible image. The main difference is that direct-lit backlights sit behind the LCD panel to provide the necessary lighting whereas edge-lit screens have LEDs sitting at the perimeter of the screen. Here are some other notable differences:
The first generation of LED backlighting was edge-lit. However, this early form of edge-lit technology caused the development of hotspots on the screen and the overall lighting was inadequate. As LED design became more efficient and effective, Samsung revisited this type of backlighting with a market-leading edge-lit LED television in 2009.
Direct-lit panels use a simple array of LEDs to provide uniform lighting across an entire LCD panel. The adoption of direct-lit screen technology in the 2000s was driven by the availability of white LEDs that could replace existing CCFL technology.
The name "LED TV" sounds simple enough, but it"s important to remember that these inch-thin sets are actually otherwise normal LCD (liquid-crystal display) TVs that use LEDs (light-emitting diodes) instead of the standard fluorescent backlights. But it gets even more confusing. We"ve reviewed LED-based LCD displays before, most recently the Sony KDL-55XBR8 and Samsung LN46A950--the two best-performing LCD TVs we"ve ever tested. A lot of the credit for those TVs" excellent picture quality can be attributed to their local dimming technology; groups of LEDs behind the screen can be dimmed or turned off to achieve those deep, inky blacks we all love so much.
The 2009 Samsung LED TVs we"re previewing here do not utilize local dimming, so we don"t expect them to match the picture quality of the local dimming sets. Of course, we"ll know more once we can review one. In the meantime, we"ll refer to the new displays as "edge-lit LED-based LCDs." More complex, we know, but also quite a bit more accurate.
The slideshow above goes into the nitty-gritty behind, or along the edge of, the technology. The short story is that the LEDs themselves are arranged along all four edges of the screen, and a special "light guide" sends light toward the middle. The result, according to the company, is similar uniformity characteristics to standard backlit LCD displays.
The downside is that they"re extremely expensive. The cheapest model, the 32-inch UN32A6000 ($1,599), will cost more than twice as much as the company"s standard 1080p 32-incher, model LN32B530 ($749) does. The 46-inch UN46B6000 ($2,799) pictured at the top commands a $700 premium over the equivalent standard 120Hz set, model LN46B650 ($2099). The step-up LED-based LCDs cost more for extra features like
There are two types of LED TV - edge-lit and back-lit televisions. So what is the difference, and is it important? Find out everything you need to know.
Different parts of the screen can have the blocks of lights switched on or off at any time, which gives the TV a much better contrast ratio than a traditional LCD TV.
A downside is that the power consumption of these TVs can be greater than standard LCD or edge-lit televisions – especially those models which use RGB LEDs.
The advantage over an edge-lit TV is that the lighting will usually be more uniform across the screen – eliminating the light-pooling of edge-lit screens.
The lights in edge-lit LED televisions are placed around the perimeter of the LCD screen – and the light they emit spreads across the back of the panel using a series of ‘light guides.’
What"s a backlight? Well, it"s the light source that is situated directly behind the LCD panel of the majority of TVs. It"s what makes the screen glow, what gives bright colors their vibrancy, and increasingly, what gives dark shadows their depth.
There"s a little more to the glowing panel of an LCD TV than you might expect. The LCD panel offers the shape and color components of an image, but it doesn"t actually produce any light of its own. And without light to produce the colors we see and project the image outward to the viewer, an LCD TV wouldn"t be worth much. Enter the humble backlight.
Behind the LCD panel is a backlight, and between the backlight and the LCD panel are usually a few layers of polarized filters, backlight diffusers, and other optical layers designed to turn this collection of tech components into a sharper viewable image.
You"ll have an LCD panel to provide much of the image content, and a backlight behind it to provide the light that makes that LCD panel visible and the colors vivid. But that backlight has undergone a lot of changes over time — several just within recent years. And a lot of the improvements we"ve seen in modern TVs can be traced to the humble backlight.
But with the advent of LCD-based flat screen TVs, the need arose for illumination, and originally that meant cold cathode fluorescent lamps (CCFL), a technology that"s similar to fluorescent and neon lighting. But because these lamps generate heat that can damage a display and aren"t terrible energy-efficient, they"ve pretty much disappeared from today"s TVs.
Instead, they were replaced by one of the biggest innovations in modern TV technology: LED backlighting. With this change, TV manufacturers started calling LCD TVs with LED backlight "LED TVs" to differentiate them from the older CCFL-lit models. But with the last CCFL TVs going off the market a decade ago, it"s just as likely that TV makers have kept the LED nomenclature around to blur the distinction between LCD TVs and OLED panels, which use a very different (and largely superior) display technology.
Edge-lit displays illuminate the LCD panel by setting a row of LEDs along the top and bottom edges of a screen, or ringing the perimeter of the TV frame with LED lights. This light is then distributed across the back of the LCD panel with a special diffuser light guide, a semi-transparent sheet of plastic that allows the light from the LED in the TV bezel to illuminate a larger portion of the display.
It"s a very cost effective way to light a TV, since it uses the least amount of LEDs. It also offers some level of dynamic backlight control for HDR support. On sets that are equipped to do so, portions of the edge lighting strips can be darkened or dimmed to provide deeper blacks, or brightened to accentuate brighter portions of the screen. However, since they don"t directly light the LCD panel from behind, the effect is considerably muted when compared to other backlight technologies.
Direct lit LED backlighting uses LED lighting across the back of the TV, directly behind the LCD panel, providing a fairly uniform amount of light across the screen. It also allows for a brighter picture, since it uses more LEDs, and is able to utilize more of the light coming from those LEDs.
However, an all-white back light alone has its limitations. Because the entire LCD panel is lit uniformly, there"s little to no dynamic range offered by the display.
Toshiba C350 Fire TV (2021 model)The Toshiba C350(opens in new tab) is one of the better Amazon Fire smart TVs we"ve reviewed, but the direct LED backlight is something of a double-edged sword. It"s better and brighter than a basic edge-lit LED backlight, and picture is better as a result, but the lack of local dimming means that – despite the TV"s support for Dolby Vision and HDR10 formats – HDR content just doesn"t look very good.
Local dimming has been further refined with the introduction of mini-LEDs. By shrinking the LED size down to about one-fifth the size – mini-LEDs measure 0.008-inch (200 microns) across – more LEDs can be packed into the backlight panel, and much smaller dimming zones to be used.
Samsung QN90A Neo QLED TVWhen it comes to the several TVs on the market that have mini-LED backlight, the Samsung Neo QLED takes the top spot, holding the top position among the best TVs we"ve reviewed. It"s a great TV for many reasons, but the impeccable backlight and HDR performance of the Samsung QN90A Neo QLED TV(opens in new tab) makes it one of the best LCD TVs we"ve ever seen.
OLED displays have individual pixels that light up without the need for a separate illumination source, creating a self-emissive display panel that doesn"t need any sort of backlight.
NEC"s 80" V801-AVT commercial-grade large-screen LCD display is ideal for applications requiring considerable screen size and integrated digital tuner. It gives digital signage users the biggest bang for their buck with AV inputs and a built-in ATSC digital tuner (SB-03TM) at a cost-conscious price. The V801-AVT"s full high-definition panel is capable of displaying brilliant imagery and capturing the audience"s attention, making it ideal for use in retail stores, restaurants, indoor venues, training facilities and corporate boardrooms.
Edge lit BLUs using light guide plates are mature technology and remain a cost effective back light for many types of displays. It creates uniform and bright light output in computer monitors, mobile devices, and commercial displays. LCDs driven by edge lit back light units are a mainstay in cost effective displays found in mobile phones, laptops, tablets, and automotive displays, to name a few. They are reliable and produce uniform light, but extracting the maximum light output can prove challenging. BrightView now offers Gain Enhancement films (GEFs) based on our micro lens array technology that provides a boost in brightness for edge lit displays. The GEF replaces the traditional down diffuser, resulting in a brighter, more efficient backlight.Up to 30% improvement in brightness compared to traditional down diffuser films
Modern LCD TVs rely on LED backlighting to produce the visuals you see on the screen. But their picture quality and price can differ based on their backlighting system. So, what are these backlighting systems, and how are they different?
LCD TVs can be grouped into three categories based on the type of LED backlighting system: Direct-lit, edge-lit, and full-array. As the name suggests, direct-lit TVs feature a panel of LEDs placed directly behind the display stack. Full-array TVs have a similar LED placement, but the number of LEDs is significantly more, and these LEDs are divided into different zones. But unlike both direct-lit and full-array TVs, edge-lit TVs have LEDs on the perimeter, and depending on the TV, these LEDs may or may not be grouped into multiple zones.
The LED backlight zones in full array and edge-lit TVs are significant as they enable the manufacturers to implement a feature called local dimming. It allows TVs to control the backlight on a scene-by-scene basis. So the TV can turn off LED backlighting in parts of the screen where it’s supposed to be darker while keeping other parts lit. As a result, LCD TVs with local dimming can produce deep, uniform blacks and have a better contrast ratio than the LCD TVs that don’t have this feature.
Direct lighting is the newest of the three types backlighting in LCD TVs. The first commercial direct-lit LCD TVs emerged around 2012 and are essentially an off-shoot of the full-array TVs.
But, the lower number of LEDs also means they have to be placed farther away from the screen to offer sufficient light coverage across the panel. As a result, direct-lit TVs are usually thicker than TVs with other backlighting systems.
Additionally, the lack of backlight control limits the contrast ratio of direct-lit LCD TVs to the native contrast ratio of the panel. So if a direct-lit TV uses a VA-type LCD panel, it will have a reasonable contrast ratio, but TVs with IPS-type panels have a poor contrast ratio.
Sony X85J is a direct-lit 4K LCD TV. It uses a VA-type panel and comes with features like HDMI 2.1 ports, VRR support, and Android TV operating system.
Edge LED backlighting first appeared in TVs in 2008, allowing for a thinner profile than LCD TVs with other backlighting solutions. But as the LEDs are placed on the rim of the screen, edge-lit TVs require a diffuser to light up the entire display adequately. This adds to their cost, making them slightly more expensive than direct-lit TVs. But given that backlighting is just one part of an LCD TV’s cost, you will find both cheap and costly edge-lit TVs on the market.
Some edge-lit TVs also come with local dimming support. But the number of backlight zones is typically far lower than in full-array TVs, and the individual LEDs are responsible for lighting up entire columns of the screen. So edge-lit local dimming is much less precise, and the benefit in terms of contrast ratio is minimal.
Full-array TVs have the best backlight implementation among LCD TVs. Not only do these TVs have a large number of LEDs, but the LEDs are also divided into multiple zones for dynamic backlight control. So, depending on the number of backlight zones and local dimming implementation, full-array TVs can have modest to excellent improvement over the native contrast ratio of the LCD panel.
Unfortunately, LCD TVs with full-array local dimming can also suffer from various screen artifacts, such as blooming and black crush, depending on the number of backlight zones and the overall local dimming implementation.
The Samsung QN90A is one of the best LCD TVs on the market and it uses full-array local dimming. The TV has 4K resolution, HDMI 2.1 port, and a 120Hz VA-type panel.
If you are shopping for a new TV and curious about its backlighting system, you can consult the TV’s specifications. Manufacturers generally mention whether an LCD TV is direct lit, edge lit, or full array. In the case of full-array TVs, the number of local dimming or backlight control zones is also listed in the TV’s specifications. This number is usually different for different sizes of a particular TV and can impact the amount of contrast ratio gain you can expect.
OLED TVs are self-emissive and don’t need a backlight, unlike LCD TVs. Instead, each pixel of an OLED panel can generate its own light and be switched off to display the perfect black color. So, OLED TVs essentially offer pixel-level local dimming. As a result, they have a near-infinite contrast ratio and are generally considered to have the best picture quality. But they are also typically more expensive than LCD TVs and can suffer from burn-in.
All-in-all, the backlight system of an LCD TV can impact its picture performance. And if you are shopping for a new TV, full-array TVs generally have the best picture quality. But if you are restricted by your budget, direct and edge-lit TVs can also deliver good visual performance. But make sure to read expert reviews to get a better idea about the overall quality of a particular television.
LCD panels are backlit by LED lights, so they rely on a backlight behind the panel to make the picture visible, and the LCD layer can"t prevent all light from escaping out of the screen. This means that even in a black scene, the backlight is still on, and some light escapes, causing blacks to appear gray.
Frame dimming: Frame dimming, or CE dimming on Samsung TVs, is a basic version of local dimming, but it dims the entire backlight instead of zones. Usually found on edge-lit TVs, it causes small highlights to become dim as well. It may improve the contrast a bit, but it"s not very useful for most scenes.
Local dimming features on LED TVs are a way to improve the contrast ratio. Since these TVs consist of LED backlights behind an LCD panel, local dimming aims to turn off, or dim, certain zones of the LED backlight, making blacks look darker and highlights brighter. However, there may be some issues with local dimming on some TVs as it could cause blooming around bright objects or for entire zones to light up when there"s a small object. Overall, most local dimming features on modern TV do an effective job at improving the picture quality in dark scenes, and only some lower-end models will have glaring problems.
Shopping for a new TV is like wading through a never-ending pool of tech jargon, display terminology, and head-spinning acronyms. It was one thing when 4K resolution landed in the homes of consumers, with TV brands touting the new UHD viewing spec as a major marketing grab. But over the last several years, the plot has only continued to thicken when it comes to three- and four-letter acronyms with the introduction of state-of-the-art lighting and screen technology. But between OLEDs, QLEDs, mini-LEDs, and now QD-OLEDs, there’s one battle of words that rests at the core of TV vocabulary: LED versus LCD.
Despite having a different acronym, LED TV is just a specific type of LCD TV, which uses a liquid crystal display (LCD) panel to control where light is displayed on your screen. These panels are typically composed of two sheets of polarizing material with a liquid crystal solution between them. When an electric current passes through the liquid, it causes the crystals to align, so that light can (or can’t) pass through. Think of it as a shutter, either allowing light to pass through or blocking it out.
Since both LED and LCD TVs are based around LCD technology, the question remains: what is the difference? Actually, it’s about what the difference was. Older LCD TVs used cold cathode fluorescent lamps (CCFLs) to provide lighting, whereas LED LCD TVs used an array of smaller, more efficient light-emitting diodes (LEDs) to illuminate the screen.
Since the technology is better, all LCD TVs now use LED lights and are colloquially considered LED TVs. For those interested, we’ll go deeper into backlighting below, or you can move onto the Local Dimming section.
Three basic illumination forms have been used in LCD TVs: CCFL backlighting, full-array LED backlighting, and LED edge lighting. Each of these illumination technologies is different from one another in important ways. Let’s dig into each.
CCFL backlighting is an older, now-abandoned form of display technology in which a series of cold cathode lamps sit across the inside of the TV behind the LCD. The lights illuminate the crystals fairly evenly, which means all regions of the picture will have similar brightness levels. This affects some aspects of picture quality, which we discuss in more detail below. Since CCFLs are larger than LED arrays, CCFL-based LCD TVs are thicker than LED-backlit LCD TVs.
Full-array backlighting swaps the outdated CCFLs for an array of LEDs spanning the back of the screen, comprising zones of LEDs that can be lit or dimmed in a process called local dimming. TVs using full-array LED backlighting to make up a healthy chunk of the high-end LED TV market, and with good reason — with more precise and even illumination, they can create better picture quality than CCFL LCD TVs were ever able to achieve, with better energy efficiency to boot.
Another form of LCD screen illumination is LED edge lighting. As the name implies, edge-lit TVs have LEDs along the edges of a screen. There are a few different configurations, including LEDs along just the bottom, LEDs on the top and bottom, LEDs left and right, and LEDs along all four edges. These different configurations result in picture quality differences, but the overall brightness capabilities still exceed what CCFL LCD TVs could achieve. While there are some drawbacks to edge lighting compared to full-array or direct backlight displays, the upshot is edge lighting that allows manufacturers to make thinner TVs that cost less to manufacture.
To better close the local-dimming quality gap between edge-lit TVs and full-array back-lit TVs, manufacturers like Sony and Samsung developed their own advanced edge lighting forms. Sony’s technology is known as “Slim Backlight Master Drive,” while Samsung has “Infinite Array” employed in its line of QLED TVs. These keep the slim form factor achievable through edge-lit design and local dimming quality more on par with full-array backlighting.
Local dimming is a feature of LED LCD TVs wherein the LED light source behind the LCD is dimmed and illuminated to match what the picture demands. LCDs can’t completely prevent light from passing through, even during dark scenes, so dimming the light source itself aids in creating deeper blacks and more impressive contrast in the picture. This is accomplished by selectively dimming the LEDs when that particular part of the picture — or region — is intended to be dark.
Local dimming helps LED/LCD TVs more closely match the quality of modern OLED displays, which feature better contrast levels by their nature — something CCFL LCD TVs couldn’t do. The quality of local dimming varies depending on which type of backlighting your LCD uses, how many individual zones of backlighting are employed, and the quality of the processing. Here’s an overview of how effective local dimming is on each type of LCD TV.
TVs with full-array backlighting have the most accurate local dimming and therefore tend to offer the best contrast. Since an array of LEDs spans the entire back of the LCD screen, regions can generally be dimmed with more finesse than on edge-lit TVs, and brightness tends to be uniform across the entire screen. Hisense’s impressive U7G TVs are great examples of relatively affordable models that use multiple-zone, full-array backlighting with local dimming.
Because edge lighting employs LEDs positioned on the edge or edges of the screen to project light across the back of the LCD screen, as opposed to coming from directly behind it, it can result in very subtle blocks or bands of lighter pixels within or around areas that should be dark. The local dimming of edge-lit TVs can sometimes result in some murkiness in dark areas compared with full-array LED TVs. It should also be noted that not all LED edge-lit TVs offer local dimming, which is why it is not uncommon to see glowing strips of light at the edges of a TV and less brightness toward the center of the screen.
Since CCFL backlit TVs do not use LEDs, models with this lighting style do not have dimming abilities. Instead, the LCD panel of CCFL LCDs is constantly and evenly illuminated, making a noticeable difference in picture quality compared to LED LCDs. This is especially noticeable in scenes with high contrast, as the dark portions of the picture may appear too bright or washed out. When watching in a well-lit room, it’s easier to ignore or miss the difference, but in a dark room, it will be, well, glaring.
An OLED display uses a panel of pixel-sized organic compounds that respond to electricity. Since each tiny pixel (millions of which are present in modern displays) can be turned on or off individually, OLED displays are called “emissive” displays (meaning they require no backlight). They offer incredibly deep contrast ratios and better per-pixel accuracy than any other display type on the market.
Because they don’t require a separate light source, OLED displays are also amazingly thin — often just a few millimeters. OLED panels are often found on high-end TVs in place of LED/LCD technology, but that doesn’t mean that LED/LCDs aren’t without their own premium technology.
QLED is a premium tier of LED/LCD TVs from Samsung. Unlike OLED displays, QLED is not a so-called emissive display technology (lights still illuminate QLED pixels from behind). However, QLED TVs feature an updated illumination technology over regular LED LCDs in the form of Quantum Dot material (hence the “Q” in QLED), which raises overall efficiency and brightness. This translates to better, brighter grayscale and color and enhances HDR (High Dynamic Range) abilities.
And now to make things extra confusing, part of Samsung’s 2022 TV lineup is being billed as traditional OLEDs, although a deeper dive will reveal this is actually the company’s first foray into a new panel technology altogether called QD-OLED.
You"re likely reading this article on a liquid crystal display (LCD). "LCD" refers to any display type that uses liquid crystals, including TN, IPS, and VA (which we"ll get into shortly). Even an old-school calculator or digital watch can use an LCD. But a simple "LCD" designation doesn"t tell you how a screen will perform. You need more information, like the backlight type the panel uses—usually LED, followed by the more expensive Mini LED.
LCDs long ago ousted cathode ray tube (CRT) and plasma displays as the dominant consumer display tech. In the past, it was common to find LCDs with cold cathode fluorescent lamp (CCFL) backlights, but most LCD displays today use LED backlights (more on that below).
TN, IPS, and VA are the three primary types of LCD displays you"ll find in TVs, monitors, and laptops. They all vary in how they use their liquid crystals. Each could warrant its own article, but we"ll keep it simple here by focusing on the differences you can expect to see in real life. Advertisement
It"s easier to reach high refresh rates and low response times with TN displays, although pricier IPS and VA are catching up. It"s worth noting that the upcoming Asus ROG Swift 500 Hz Gaming Monitor, which should be the fastest monitor on the market, purportedly achieves its refresh rate via an "E-TN" panel that claims 60 percent better response times than regular TN. So while you can buy a supremely fast IPS (up to 360 Hz) or VA monitor, TN is still the technology pushing the limits of refresh rates.
VA panels excel in contrast, which is often considered the most important factor in image quality. VA monitors commonly have contrasts of 3,000:1, while a typical IPS comes in at 1,000:1. IPS Black displays, which started coming out this year, claim to double the contrast of typical IPS monitors to up to 2,000:1. We reviewed the IPS Black-equipped Dell UltraSharp U2723QE, and the difference was noticeable.
Most television companies, as well as sellers, misguide consumers by saying that this particular TV is not LCD but LED. So, first of all, we need to understand that all TVs are basically only
LCDs. What we refer to as LED is simply an update to the existing LCD panels. The panel technology is the same, however, the backlight is entirely different. Those LCDs that use LEDs as a light source are generally termed as LEDs. In short, a LED-backlight is a replacement for the uniform CCFL (Cold Cathode Fluorescent Light) backlight that previously gave LCD TVs its brightness.
Initially, there were only CCFL-backlit LCDs, but with advancement in technology, these CCFL were replaced by LEDs, as not only they dramatically reduced power consumption by over 40 percent compared to conventional CCFL-backlit LCDs, we got more control over the image quality by modulating these individual LEDs.
In the LED-backlit LCDs, LED lights can switch on and off individually, which allows the image to have greater contrast, bright whites and deep black in the same image. Thus, producing a superior picture when compared to CCFL-backlit LCDs. LCD TVs with LEDs also offer better response time in comparison to CCFL-backlit LCDs.
In the traditional LCDs, the CCFL lights were spread all across the surface behind the display screen, but there was no control over them. It means that when we switched on our TV, the entire surface behind the screen used to get illuminated by these CCFL lights that were always ON, and we were unable to control their dimming in specific areas of the screen.
Because of this, even the dark part of the picture used to be illuminated like the rest and we were unable to achieve images with convincing blacks, as light passed through the dark part of the picture and made it appear grey. In other words, the contrast of CCFL-backlit LCD panels isn’t very good. However, a plasma TV doesn’t have this problem as each pixel can light up or switch-off according to the demand of the picture.
Now coming to LCDs that use LEDs as the source of illumination, there are basically three types. One is Full-array backlighting, another is Edge-lit backlighting (ELED) and third is direct-lit LED backlights (DLED).
The term full-array is used where LEDs cover the entire back-side of the LCD panel. Full-array TVs are high-ends TVs that are heavier and often thicker, but they provide better picture quality as all parts of the screen are evenly backlit. They offer the most effective local dimming, as the LEDs are more in number and are spread over the entire back surface of the panel. The independent dimming of each LED in these TV sets helps in achieving perfect blacks. But, as they are costlier to manufacture, they are rare.
This technology allows the designing and manufacturing of exceptionally thin TV sets. Edge-lit sets also have a cost-benefit over direct, local dimming versions (DLED) as fewer LEDs are used in them. Because of which, they are power efficient too.
Direct-lit LED backlights are an offshoot of full-array backlighting, though they use significantly fewer LEDs across the back of the panel. In this technology, several rows of LEDs are placed behind the entire surface of the screen.
As the LEDs are behind the LCD panel in DLED TVs, dual modulation works far more efficiently and the TVs can have better overall brightness and contrast. Using a feature called local dimming, the LEDs are divided into a number of zones that can be individually controlled, so some portions of the backlight can be dimmed while other remain illuminated.
Though different brand TVs might be using the same DLED or ELED backlighting, their image quality might differ considerably depending on how many lights are used and how they are aligned. In some budget Edge-lit TVs, LEDs are aligned on only one side, either upper or lower edge of the TV panel, while others might have LEDs on both upper and lower edges of the panel. The high end TVs might even have a row of LEDs on all four edges of the panel. Some manufacturers use both Edge and Direct LED systems for LCD TVs. The best professional monitors use direct LEDs.
Though bigger brands like Sony, Samsung and LG also prefer EDGE-lit LED backlighting in their TVs, they complement it with some of their indigenously formulated technology to enhance the picture quality.
TV manufacturers lay more stress on producing TVs with ELED technology as it not only cut down upon their expenditure but allows them the liberty of producing ultra-slim TV sets that can appeal the masses with their aesthetically designed panels.