edge-lit lcd panel for sale
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.’
When comparing different models of televisions, you might see the term "edge-lit LED." All LED TVs are a type of LCD TV; the "LED" refers only to the kind of lighting source used to illuminate the LCD pixels in the television. There is more than one way to light the pixels. The two primary technologies are edge-lit and full-array.
In an edge-lit television, the LEDs that illuminate the LCD pixels are located only along the edges of the set. These LEDs face inward toward the screen to illuminate it.
In some poorer-quality edge-lit LEDs, uniform picture quality can be a problem. Because the LEDs are along the edges of the panel, quality declines as you approach the middle of the screen because a uniform amount of illumination is not reaching the pixels further from the edges. Again, this is more noticeable during scenes of darkness; the black along the sides of the screen is more gray than black (and corners can appear to have a flashlight-like quality of illumination emanating from the edges).
Full-array LED televisions use a full panel of LEDs to illuminate the pixels. Most of these sets also have local dimming, which means the LEDs can be dimmed in different regions of the panel while other areas are not. It helps improve black levels, which appear closer to black than dark gray.
In general, full-array LED is a superior technology when it comes to picture quality, but edge-lit sets have one significant advantage: depth. Edge-lit LED TVs can be much thinner than those lit with either a full LED panel or traditional fluorescent (non-LED) backlight. For that reason, most of the super-thin sets you see in stores will be edge-lit.
If you"re looking for the best possible picture quality, you are most likely to find it in a full-array LED display with local dimming. If you are primarily concerned about the appearance of the television and want an extremely thin screen, edge-lit is the style that will fit your needs.
Here"s the "exploded" view of the edge-lit LED-based LCD display. In the foreground is the frame, followed by the LCD element, then the LED lighting assembly.
The heart of the beast is the LED lighting assembly. The LEDs themselves are arranged in strips on all four sides of the panel (the bottom strip was removed for this display). A series of filters, a "light guide," and a reflecting back serve to translate the LEDs" light toward the LCD display itself.
Here"s a closer look at the assembly. The rightmost, thinner three panels are the color filter, polarizing filter, and diffuser. The leftmost, notched white panel is the reflecting back, the only one of the five elements that sits behind the row of LEDs (top).
Second from the left is the clear-looking, thicker "light guide," a proprietary Samsung development that uses a series of tiny lens-like refractors to send light from the LEDs along edges toward the middle of the screen. The company claims its edge-lit LED-based LCDs have the same uniformity characteristics as its standard backlit LCD displays. If true, that would be an improvement on the only other edge-lit display we"ve reviewed so far, the Sony KLV-40ZX1M.
Here"s a closeup of the LEDs themselves, which are visible along the strip at the top. Despite their yellowish appearance, each produces white light, which is filtered and sent through the LCD panel. According to Samsung, the advantage of using white LEDs, as opposed to the multicolored "triluminous" LEDs in Sony"s XBR8 models, is purer reproduction of color-corrected primary and secondary colors at low luminance levels, as well as better energy efficiency.
Here"s where we mention that, unlike so-called local dimming LED based displays we"ve reviewed in the past, these edge-lit models can"t dim or turn off the LEDs selectively. That"s why we expect that the black-level performance of edge-lit LED-based LCD displays won"t match that of local dimming models, such as the Sony XBR8 or Samsung"s own A950 series.
Industry standards for flat-screen televisions have transitioned away from LCD in the past few years due to several factors. Not only were they slower to respond, but they also increased your electric bill in the long run. Additionally, the contrast of the presentation of colors was off making shades of blacks appear grey.
These aforementioned problems with LCD screen televisions made way for LED TVs to take over the market, as they resolve all of the negative attributes associated with LCD televisions. In comparison, LED TVs have better response time, more brightness, and are more energy efficient. However, there are different types of LED TV’s that affect the picture and look of the screen.
Direct Lit LED TVsare televisions that have LED lighting located directly in back of the LCD panel. With the amount of coverage this execution has, overall all brightness and contrast is better than Edge Lit LED TVs. Direct Lit LED TVs are generally thicker and more expensive to produce.
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.
The Hisense U8H matches the excellent brightness and color performance of much pricier LCD TVs, and its Google TV smart platform is a welcome addition. But it’s available in only three screen sizes.
The Hisense U8H is the best LCD/LED TV for most people because it delivers the performance of a much pricier TV yet starts at under $1,000, for the smallest (55-inch) screen size. This TV utilizes quantum dots, a full-array backlight with mini-LEDs, and a 120 Hz refresh rate to deliver a great-looking 4K HDR image. It’s compatible with every major HDR format. And it’s equipped with two full-bandwidth HDMI 2.1 inputs to support 4K 120 Hz gaming from the newest Xbox and PlayStation consoles. Add in the intuitive, fully featured Google TV smart-TV platform, and the U8H’s price-to-performance ratio is of inarguable value.
In terms of design, the Hisense U8H is not as svelte as our upgrade pick, but it’s plenty sturdy and doesn’t look or feel cheap. Two narrow, metal feet jut out from beneath the panel and steadily hold the TV. They can be attached in two separate spots, either closer in toward the middle of the panel or out toward the edges, to account for different-size TV stands. The feet are also equipped with cable organization clasps—a nice touch for keeping your TV stand free of cable clutter. Though the TV is primarily plastic, its bezels are lined with metal strips, providing a bit more durability in the long run. I moved it around my home, and it was no worse for wear, but we’ll know more after doing some long-term testing.
The Hisense U8H has some difficulties with banding, or areas of uneven gradation, where transitions that should appear smooth instead look like “bands” of color (sometimes also called posterization). Like many current 4K HDR TVs, the U8H uses an 8-bit panel rather than a 10-bit panel, which affects the color decoding and color presentation process. This is usually relevant only with HDR video and games. When playing games on the PlayStation 5 and Xbox Series X, I saw a few instances where the content wasn’t rendered correctly and displayed ugly splotches of color on the screen. However, this almost always occurred during static screens (such as a pause menu or loading screen); I rarely spotted it during actual gameplay. Hisense has stated that it would address the problem in a future firmware update, but at the time of writing it was still present. This is a flaw that may give dedicated gamers pause, but we don’t consider it to be a dealbreaker for most people.
Finally, like most TVs that use vertical alignment (VA) LCD panels, the U8H has a limited horizontal viewing angle, which may be a bit annoying if you’re hoping to entertain a large crowd. Our upgrade pick uses a special wide-angle technology to address this.
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.
LED Edge Lit PanelsAt Buy LED Online, we offer a great selection of edge-lit LED panel lights from industry-leading manufacturers. Edge-lit LED lights can provide beautiful overhead lighting in a low-profile, minimalist-style fixture without the uncomfortable glare that exposed bulbs have been known to produce. These edge-lit LED light fixtures are perfect for use in kitchens, bathrooms, and other areas that require soft lighting without the harsh glare of direct lighting. Our edge-lit LED panel lights are available in a range of colors, so you can find the perfect fixtures for your residential or commercial needs. You can also choose between direct-wired or lay-in options.
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.