led edge lit lcd panel supplier

Lightboxes can be built to your specifications regarding size, color temperature, and frame color. Single and double-sided [illuminated on the front and rear face] light panels are also available. Edge-lit panels are 8mm or about 1/3-inch thick a light panel including a flip-open frame [now called a lightbox] has a thickness of 0.625 to 1.50-inches. Illumination across the LED light panel from edge-to-edge is within 10% so a dark center is not a concern. Read more

Light panels have many uses in retail environments such as lighted shelves, signs or as a lightbox for photographic transparencies, stained glass and faux windows. For interior lighting applications, the panel performs well as a ceiling troffer, lighted wall, under cabinet light and under stone such as Onyx, quartzite or translucent man-made countertops. Read more

In signage, edge-lit panels can be a substitute for fluorescent tubes. Panels are thin, evenly illuminated and last for years without maintenance. Several color temperatures are available and RGB.

When displaying stained glass or some other translucent material in a window, you can use our clear edge-lit panel to let natural light through during the day and illuminate your art at night.

You may cancel your Mulberry Protection Plan within 30 days of purchase by contacting Post Up Stand at 1-800-935-3534. If there has been no claim filed against the plan, the plan will be void and you will receive a full refund.

The local dimming on LED TVs is a key way of introducing contrast. With this technology, the intensity of lighting adapts to the image shown achieving contrast ratios.

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.

The use of LEDs creates an extremely bright picture. This can lead to black and naturally dark tones appearing too bright, a phenomenon known as ‘elevated black levels’. This appearance can really affect wide-screed films, especially as there is no way to alter the backlight of specific portions of the screen. This has led to the development of alternative backlighting arrangements that minimize the greying of black sections of the 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.

Direct-lit performs across a range of viewing angles and colors, but it is limited by not being able to increase contrast, as the entire backlight has to be dimmed to change color intensity. This affects the ability of a screen to achieve a deep black tone. Full array lighting and flexible backlight technologies have superseded direct-lit lighting. They are more advanced and can achieve more nuanced imaging effects.

Edge Lit screens can achieve full, deep blacks as they can use local dimming technology to reduce lighting in areas of the screen that display black or dark colors.

LCDs need to be supported by additional lights because they don’t produce their light. To create this light, you can either use edge-lit LEDs or backlit LEDs. The primary difference between edge-lit and backlit LEDs is in the lighting is arranged. The light sources of Edge-lit displays are placed on a diffuser (usually thin) behind the LCD to create light dispersion.

The significant advantage of using an Edge-lit flat panel lights LED display is the reduced thickness. As a result of this, the displays are placed on Edge and not directly behind the LCD. It leads to the thinness of the diffuser. Most thin diffusers are usually edge-lit and not backlit, and they transfer the majority of the components to a big stand.

Switching from fluorescent troffer lights to LED troffer lights has its benefits, but the process could prove to be daunting and not so easy. You could either use Edge-lit panels or Backlit panels. Here are the significant differences between these panels.

Concerning the location of the LEDs, Edge-lit light panels are placed on the Edge of the frame. The light that emits is guarded by a light guard panel that directs it sideways. The light board is designed for the smooth and evenly distribution of light in a given space. The sleek look of the diffusers is a result of the small depth of the panel. The installation of Edge-lit can be done in a standard grid ceiling. And the sleekness and thinness of the board make it possible to install Edge-lit LEDs on walls and ceilings using suspension box or cable installation kits.

Backlit, as the name implies, is placed at the back of the frame instead of at the Edge. This position causes the LED to shine directly out, straight through the diffuser. In backlit LED, there is no light guard. As a result of this, the light shines directly outward and does not need to be directed. The straight direct light does not cause a glare because the backlit LED also has a diffuser which smoothens the light. The risk of yellowing of light guard is absent because there is no need for one. The directness of the LED light makes backlit more efficient than edge-lit. Unlike in edge-lit, where the light travels through the diffuser panel, light only passes through the thickness of the material in backlit.

The disadvantage of Backlit is the thickness of its diffuser. You cannot install it just anywhere. It has to be installed in a drop grid ceiling. Although its panel is thicker than Edge-lit, it is still easy to operate due to its lightweight around its surface.

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.

This type of lamp has managed to produce high-quality televisions. But, there have always been disadvantages to this technology, such as poor contrast ratios and color reproduction.

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.

Therefore, a back-lit LED TV with local dimming produces a better picture, which helps it to create an image comparable with other TV technologies like OLED.

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.

These models are thin and light at the mild expense of some picture quality—specifically in the area of black levels. Black areas of the picture, such as a dark night scene, are not truly black but more like a very dark gray since the lighting is coming from the edge and illuminating the dark areas a bit more.

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.

An LED-backlit LCD is a liquid-crystal display that uses LEDs for backlighting instead of traditional cold cathode fluorescent (CCFL) backlighting.TFT LCD (thin-film-transistor liquid-crystal display) technologies as CCFL-backlit LCDs, but offer a variety of advantages over them.

While not an LED display, a television using such a combination of an LED backlight with an LCD panel is advertised as an LED TV by some manufacturers and suppliers.

A 2016 study by the University of California (Berkeley) suggests that the subjectively perceived visual enhancement with common contrast source material levels off at about 60 LCD local dimming zones.

LED-backlit LCDs are not self-illuminating (unlike pure-LED systems). There are several methods of backlighting an LCD panel using LEDs, including the use of either white or RGB (Red, Green, and Blue) LED arrays behind the panel and edge-LED lighting (which uses white LEDs around the inside frame of the TV and a light-diffusion panel to spread the light evenly behind the LCD panel). Variations in LED backlighting offer different benefits. The first commercial full-array LED-backlit LCD TV was the Sony Qualia 005 (introduced in 2004), which used RGB LED arrays to produce a color gamut about twice that of a conventional CCFL LCD television. This was possible because red, green and blue LEDs have sharp spectral peaks which (combined with the LCD panel filters) result in significantly less bleed-through to adjacent color channels. Unwanted bleed-through channels do not "whiten" the desired color as much, resulting in a larger gamut. RGB LED technology continues to be used on Sony BRAVIA LCD models. LED backlighting using white LEDs produces a broader spectrum source feeding the individual LCD panel filters (similar to CCFL sources), resulting in a more limited display gamut than RGB LEDs at lower cost.

Using PWM (pulse-width modulation), a technology where the intensity of the LEDs are kept constant but the brightness adjustment is achieved by varying a time interval of flashing these constant light intensity light sources,

A first dynamic "local dimming" LED backlight was public demonstrated by BrightSide Technologies in 2003,Sony in September 2008 on the 40-inch (1,000 mm) BRAVIA KLV-40ZX1M (known as the ZX1 in Europe). Edge-LED lighting for LCDs allows thinner housing; the Sony BRAVIA KLV-40ZX1M is 1 cm thick, and others are also extremely thin.

LED-backlit LCDs have longer life and better energy efficiency than plasma and CCFL LCD TVs.mercury, an environmental pollutant, in their manufacture. However, other elements (such as gallium and arsenic) are used in the manufacture of the LED emitters; there is debate over whether they are a better long-term solution to the problem of screen disposal.

Because LEDs can be switched on and off more quickly than CCFLs and can offer a higher light output, it is theoretically possible to offer very high contrast ratios. They can produce deep blacks (LEDs off) and high brightness (LEDs on). However, measurements made from pure-black and pure-white outputs are complicated by edge-LED lighting not allowing these outputs to be reproduced simultaneously on screen.

Quantum dots are photoluminescent; they are useful in displays because they emit light in specific, narrow normal distributions of wavelengths. To generate white light best suited as an LCD backlight, parts of the light of a blue-emitting LED are transformed by quantum dots into small-bandwidth green and red light such that the combined white light allows a nearly ideal color gamut to be generated by the RGB color filters of the LCD panel. The quantum dors may be in a separate layer as a quantum dot enhacement film, or replace pigment-based green and red resists normally used in LCD color filters. In addition, efficiency is improved, as intermediate colors are no longer present and do not have to be filtered out by the color filters of the LCD screen. This can result in a display that more accurately renders colors in the visible spectrum. Companies developing quantum dot solutions for displays include Nanosys, 3M as a licensee of Nanosys, QD Vision of Lexington, Massachusetts, US and Avantama of Switzerland.Consumer Electronics Show 2015.quantum dot displays at CES 2017 and later formed the "QLED Alliance" with Hisense and TCL to market the technology.

Mini LED displays are LED-backlit LCDs with mini-LED–based backlighting supporting over a thousand full array local dimming (FALD) zones, providing deeper blacks and a higher contrast ratio.

LED backlights are often dimmed by applying pulse-width modulation to the supply current, switching the backlight off and on more quickly than the eye can perceive. If the dimming-pulse frequency is too low or the user is sensitive to flicker, this may cause discomfort and eyestrain similar to the flicker of CRT displays at lower refresh rates.

Novitsky, Tom; Abbott, Bill (12 November 2007). "Driving LEDs versus CCFLs for LCD backlighting". EE Times. Archived from the original on 28 November 2010. Retrieved 21 November 2020.

LED TVs: 10 things you need to know; David Carnoy, David Katzmaier; CNET.com/news; 3 June 2010; https://www.cnet.com/news/led-tvs-10-things-you-need-to-know/

LCD Television Power Draw Trends from 2003 to 2015; B. Urban and K. Roth; Fraunhofer USA Center for Sustainable Energy Systems; Final Report to the Consumer Technology Association; May 2017; http://www.cta.tech/cta/media/policyImages/policyPDFs/Fraunhofer-LCD-TV-Power-Draw-Trends-FINAL.pdf Archived 1 August 2017 at the Wayback Machine

Polarisation-sensitive beam splitter; D.J. Broer; A.J.S.M. de Vaan; J. Brambring; European patent EP0428213B1; 27 July 1994; https://worldwide.espacenet.com/publicationDetails/biblio?CC=EP&NR=0428213B1&KC=B1&FT=D#

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.

Edge Lit LED TVs are TVs with LED lighting that surrounds the perimeter of the TV. These types of TVs are thinner, cool off more easily, and they are cheaper to manufacture.

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.

There isn’t a direct answer to this, as it really depends on the purpose of the TV. For example, the best professional monitors use Direct Lit LEDs, since overall image quality is better. However, for those who want a slim-profile TV, Edge lit is the way to go.

Need help making a decision regarding what hospitality television would best suit your business? Contact our hotel technology experts directly. They will help guide you through the different options available in our inventory.

Do you ever need a cheap, quick way to make an impressive display? Do ever want to show more than a blinking LED but want something easier to use than a LCD? Do you want to make light appear to hover in mid-air? Then give some thought to edge lighting.

At the last Maker Faire I had a bunch of interactive gizmos for people to play with, but one question I was asked more than any other was "How did you make those displays?"  On the Rock Paper Scissors Playing Glove one small display showed three different images and text while on the Secret Knock Detecting Gumball Machine the light just seemed to float in the clear plastic without an obvious source.  The answer is edge lighting.

Edge lighting exploits a fun property of light called internal reflection where light can get trapped inside a transparent material. It"s the same concept that makes both a diamond sparkle and optical fibers work. But we’re going to use it to make light come out of a sheet of plastic.

Simply put we shine a light in the edge* of a clear piece of plastic and etch it where we want the light to come out. With this simple, cheap method you can use a single LED to display words or images. Because it"s etched into a transparent surface the images can seem to float in mid air or you can layer several of them to make a single display with more than one image or color.

When light passes between two different materials (like plastic and air) at a very high angle it will get reflected back rather than passing through. You can see this in a glass of water. Look at it from above and you can see right through it. Looking at it almost edge on and it will be very reflective. This means that if we shine a light into the edge of clear plastic the light will bounce around inside until it finds a way out. By etching and/or carving the surface of the plastic we control where it escapes.

Slim down an LED. We want to get as much light as possible from our LED into the plastic, so we"re going to grind down the plastic shell of the LED to fit better. You can find rectangular LEDs that will be the right thickness, but we find they"re rarely bright bright enough and come in limited colors. We used a rotary tool with a sanding cylinder, but you can use whatever works (sanding table, sand paper, grinding wheel, etc). 3mm LED"s don’t need much modification, just a tiny bit off the front and back. Be more careful when working with 5mm LEDs since you can accidentally go through the plastic case and remove some of the more important bits of the LED. Work slowly and carefully holding the LED in a pair of pliers to save your fingers. You can also shorten the height of the LED since we don"t need the lensing effect of the case.

Wire up your LED. This depends the details of your project. If you"re soldering it will be a lot easier and safer to do it now rather than when it"s embedded in the plastic. It"s also a good chance to make sure you didn"t damage the LED when grinding it to size

Cut a place for the LED in the plastic. Use your rotary tool (or a file, etc) to carve a cutout along the edge the same size as our LED. It should fit snugly with only the wires sticking out. If you"re using really thick plastic you can even drill holes in the edge to hold the light.

Hold the LED in place with aluminum tape. Apply a thin strip of aluminum tape along the edge that contains our LED. Make sure it runs on the front and back of the plastic. Cut out a notch around the LED wires so the metal on the tape doesn"t short it out. The aluminum tape will not only hold the LED in place but will direct as much light as possible back into the display.

Apply some more reflective tape along the remaining edges. This is optional, but it will improve the brightness of the display and keep light from leaking out.

If you"re not satisfied with the brightness of your display add more LEDs along the edge. Very long or large displays will be more evenly lit if you spread the LED"s along the edge.

Lets say we"re making an electronic Tic-Tac-Toe game. Ideally we want either an X or an O in the same place. To do this we make and X and an O with a separate LED for each one. Since each piece is essentially transparent when off, we can put one behind the other to have a display that can show an X or O in the same space, depending on which LED we light. You can also use the same effect to add more than one color to the same display or animate parts of an image like some animated neon signs.

If you make this Instructable, post a photo of it in comments and I"ll send you a Master of Edge Lighting achievement patch and you"ll get your name on the Hall of Fame.

I love this instructable! I was inspired to do it myself from the first time I seen it and have made a few small business card sized panels with my friends businesses on them and gave them as gifts. Yesterday I did one a little more elaborate for a good friend of mine and I think it"s the best I"ve done. Normally I wouldn"t even bother to put up a post to anything but your inspiration brought out a new skill for me to master and I thank you for that!

Looks awesome! I did one for my daughter too, however mine doesnt have a frame around it as I engraved the design a bit too close to the edge, so I made a stand instead. On the base of the display is beading that goes around the edge of laminate flooring just to tidy it up a bit. This is my 1st attempt, I may do another one later on sometime to improve on the flaws.

Once I saw this I knew exactly what I was going to do.  Build a night light for my daughter.  I built a frame around it with the power supply in the back.  The edge closest to the display is white and the outer edge is pink.  The background is light purple (some of the colors from her room, the designs are in her room also).  I was going to use black, but didn"t have any and I thought the purple looked alright.

I have used plastic sheet material that had a privacy film/2-way mirror. It made the unlit display simply a mirror but when leds powered up you only would see the embossed images thru the led

One is to use much finer lines than I show in my examples. A very fine craft knife blade can make cuts that are hard to see but will still glow if you put enough light into the edge.

Another is to place it in front of an interesting background. A complex pattern will hide what"s really there. A more complicated solution is to use two pieces of plastic. The first with your etching on it, and another behind it with its entire surface etched. When you put light into the edge of the back piece it will all light up and you won"t see the foreground piece. Light up the front piece and turn off the light on the back and the "real" message will be clear.

This Instructable really helped a lot. Ive been looking for a way to easily edge light the holographic display on the Dead Space plasma cutter i"ve been working on.ReplyUpvote

ST. PAUL, Minn.--(BUSINESS WIRE)--In an effort to meet LCD manufacturer design flexibility demands, the 3M Optical Systems Division today announced that it has developed a unique solution called Uniformity Tape that will allow LCD manufacturers to reduce the number of LEDs required for edge-lit LED LCD panels at a low cost, without sacrificing brightness or efficiency.

"As LED technology continues to improve and becomes even brighter, some backlight designs are currently using more LEDs than needed for a brightness specification in order to avoid head lighting or thick bezels. Uniformity constraints have also prevented manufacturers from removing LEDs to save on cost"

LEDs are becoming brighter and even more efficient-requiring fewer bulbs to achieve target brightness for a given display. Until now, there have been limitations as to how far LEDs can be spaced apart at the edge of an LCD panel because of dark areas that appear between LEDs when they are too far apart. This scenario is commonly referred to as "head-lighting" because it looks like the dark space on the road between the headlights of a car.

3M"s Uniformity Tape is a clear tape, which has adhesive on one side and a micro-replicated optical pattern on the other side. It is adhered to the edge of the light guide, which faces the LED light sources. The tape is designed to increase the spreading of light in the light guide from each LED, which greatly increases the allowable LED spacing. The optical pattern is spatially uniform, meaning that no positional registration of LEDs is required along its length. The Uniformity Tape keeps the edge of the display closest to the LEDs uniform in brightness when the spacing of light sources is increased. This allows panel manufacturers to save money by removing unnecessary LEDs. Uniformity Tape can also increase LED spacing by up to three times the current spacing, while maintaining edge uniformity for a given bezel size.

"As LED technology continues to improve and becomes even brighter, some backlight designs are currently using more LEDs than needed for a brightness specification in order to avoid head lighting or thick bezels. Uniformity constraints have also prevented manufacturers from removing LEDs to save on cost," noted Gilles Georges, 3M global marketing manager. "By spacing LEDs further apart for edge-lit LED LCD panels, 3M"s Uniformity Tape allows light to travel inside the light guide at wider angles-allowing manufacturers to design wider spacing between LEDs without any dark areas."

When combined with 3M"s Dual Brightness Enhancement Film (DBEF), Uniformity Tape allows display manufacturers even more design freedom to innovate and use less LEDs to create a backlight that not only meets energy standards, but also remains competitive at a low cost. Furthermore, Uniformity Tape helps device manufacturers meet the growing number of energy efficiency standards around the world.

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.

As direct-lit TVs require fewer LEDs and no backlight control, they are cheaper to produce and thus typically limited to the entry-level and mid-range segments of a TV manufacturer’s portfolio.

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.

During the Consumer Electronics Show back in January, we noticed that some TV manufacturers were debuting LCD TVs with a new type of LED backlight, a direct-lit LED backlight.

At the time we didn"t know a lot about direct-lit LED backlights, but based on where these TVs were positioned in the manufacturer"s lineup—typically in or close to the entry-level series—it appeared that direct-lit LED backlight technology was able to bridge the price gap between lower-cost CCFL (fluorescent) backlights and the newer edge LED backlights that have become increasingly common in many LCD TVs. This year, for example, both Samsung (EH series) and LG (LS3400 series) are offering lower-priced LCD TVs with direct-lit LED backlights.

Most of the LCD TVs in our TV Ratings now come with edge LED backlights, where the LEDs are arrayed around the perimeter—typically the sides—of the TV. A waveguide (or lightguide, or diffuser) then spreads the light across the entire panel, hopefully in a uniform fashion.

The other type of LED-based backlighting we"ve seen—now less common—is a full-array LED backlight, where rows of LEDs are spread across the entire back panel of the TV. 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. In some instances, we"ve seen this improve contrast and black levels. Some edge LEDs also have a form of local dimming, but this has had a negligible effect on contrast or black levels on most of the TVs we"ve tested.

Direct-lit LED backlights are an offshoot of full-array backlighting, in that they use LEDs spread across the entire back panel of the TV. (The TV"s spec page may just refer to these TVs as having a full-array backlight.) However, there are a few key differences compared to the more expensive full-array LED sets we"ve tested previously. One is that they use significantly fewer LEDs across the back of the panel. Another is that these sets lack the local dimming feature.

In addition, these TVs are much deeper than previous LED-backlit models, especially the ultra-thin edge LED sets. In fact, they more closely resemble LCD TVs with CCFL backlights. The reason: Because fewer LEDs are used, they have to be moved farther away from the screen to provide adequate light coverage across the panel, much the way the beam of a flashlight gets wider as you move it away from an object.

But the primary reason we"re seeing direct-lit LED backlights is price. Though they do cost a bit more than CCFL models, they"re less expensive than edge LED models, since they don"t require the lightguide plates. And in a tough economy, this lets manufacturers offer less-expensive models without having to forgo what has become perceived as a key LCD feature—an LED backlight. Although direct-lit LED backlights are no slimmer than CCFL-based LCD TVs, they do offer an advantage over models with fluorescent lights: better energy efficiency.

We"re currently testing a few Samsung models that use direct-lit LED backlights, so make sure to check out our TV Ratings in the next week or so to see how these sets fared. We"ll also be watching the market to see if more manufacturers embrace this type of backlight in their lower-priced LCD TV models.