OLED vs LED TV
How these two screen technologies compare
Steve Kindig has been an electronics enthusiast for over 30 years. He has written extensively about home and car A/V gear for Crutchfield since 1985. Steve is also a volunteer DJ at community radio station WTJU, where he is a regular host of the American folk show "Atlantic Weekly," as well as the world music program "Radio Tropicale."
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Most TVs sold today are based on LCD screen technology. Because these sets use an LED backlight we often refer to them as LED LCD TVs, or just LED TVs.
Plasma TVs are no longer being made, but there's another non-LCD TV technology that produces exceptional picture quality and is gaining in popularity: OLED.
This article will explain the differences between these two TV types and talk about why you might choose one or the other.
LCD and OLED TV: Two different paths to a great picture
Both OLED and LCD TVs use skinny panels with millions of pixels to create crystal-clear TV pictures. But what happens inside the two TV types is quite different.
An LCD TV (left) is a complicated design with a backlight, glass filters, diffusors, and polarizers. An OLED TV (right) doesn't need a backlight because its pixels are self-lighting.
LCD stands for Liquid Crystal Display
Liquid crystals are rod-shaped molecules that twist when an electric current is applied to them.
An LCD TV screen uses a thin layer of liquid crystal solution sandwiched between transparent glass panels. The liquid crystals aren't floating randomly — the screen's front layer of glass is etched on the inside surface in a grid pattern that forms a template to keep the crystals lined up horizontally and vertically. A matching grid of millions of transistors supplies the tiny electric charges that control the crystals, causing them to open or close. The resulting pattern of light and dark pixels creates the TV's picture.
While liquid crystals form the picture, they don't produce any light themselves. Instead, a backlight behind the LCD layer shines through it. This type of TV is technically known as a "transmissive" display — light passes through the imaging layer.
LED TVs use small, bright LEDs for illumination. LED stands for light-emitting diode. Each liquid crystal pixel acts like a shutter, either blocking light or allowing it to pass through. The pattern of transparent and dark pixels forms the image.
In any LCD TV one of the biggest factors determining picture quality is the LED backlight. The type and sophistication of the backlight have a huge effect on how well the TV can display dark or black sections of the picture.
There are three types of LED backlighting found on current LCD TVs:
- Edge-lit — Most LED TVs use edge lighting: strings of LEDs along either the sides of the screen, the top and bottom, or just the bottom. Some type of light guide is used to redirect and scatter the light evenly to produce a more uniform image. Edge-lit backlighting makes it possible to build ultra-thin TVs.
- Direct-lit — This type of backlight has a grid of LEDs across the entire back of the screen. Be careful not to confuse this type of backlight with the full-array type described next. The direct-lit approach was developed to save manufacturing costs. This design uses a few dozen LEDs, and the LEDs cannot be independently dimmed, so you don't get the exceptional picture contrast — the range between the blackest black and the brightest white the TV can produce — that you get with a full-array/local dimming design. Cosmetically, direct-lit TVs tend to be much thicker than edge-lit models.
- Full-array with local dimming — Still the gold standard for LCD TV backlighting, this type is currently found on only a handful of top-performing models. This type also features a grid of LEDs covering the entire back of the screen. Where it differs from direct-lit is the much higher number of LEDs, and the fact that each LED is an independently dimmable "zone." You get exceptionally wide contrast with very realistic shadow detail.
Over the past two years TV makers have made major advances in improving the picture quality of LED TVs — especially picture contrast and color. We'll cover them in the comparison section further down the page.
OLED TVs don't use a backlight, which helps them produce absolute black and exceptional contrast.
What is OLED?
OLED (pronounced "oh-led") stands for Organic Light Emitting Diode. The first OLED smartphone screens appeared in 2010, but OLED TVs have only been around since 2013. What's new and different about this technology is the OLED screen material — an organic substance that glows when it's activated by an electric current. This self-lighting carbon-based material makes up the screen's pixel layer — it's the reason OLED is known as an "emissive" display.
The best backlight is no backlight
In an OLED TV screen, each pixel — actually every sub-pixel — is its own independently controlled light source, so there's no need for a backlight with all its limitations. Just as important, each and every sub-pixel can switch off completely, producing absolute black. It's this ability that gives OLED its remarkable contrast and black levels. This pixel-level light control enables a level of precision and control that's never been possible before.
An OLED TV's construction is comparatively simple, with fewer layers than an LCD TV (see Panel Structure graphic, above). But that doesn't mean OLED TVs are easy (or cheap) to build. Making TV-sized OLED screens has proven very difficult, which is why early OLED models were so expensive. Prices have dropped dramatically since OLED TVs launched.
We're used to TV screens where each pixel is made up of three sub-pixels — red, green and blue — which together create the TV's color palette. LG's OLED TV technology takes a different approach. Their unique 4 Color Pixel technology adds a white sub-pixel to the three primary colors to enhance both color range and brightness.
Now that you have a better idea of how these two TV types work, let's look at how they compare when it comes to key picture quality aspects and other factors we look at when choosing a TV.
Head-to-head comparison: OLED vs LED
LED TVs cover a wide range of sizes from 19" to 85". OLED TVs are currently available in only 55", 65", and 77" models. Both LED LCD and OLED TVs are available with either flat or curved screens.
Both LED and OLED let you choose between 1080p HD (1920 x 1080 pixels) and 4K Ultra High Definition (3840 x 2160 pixels).
A TV's ability to produce deep, dark blacks is probably the most important factor in achieving excellent picture quality. Deeper blacks enable both higher contrast and richer colors, resulting in a more lifelike image.
Because OLED pixels can turn off completely to produce absolute black, OLED TV is king when it comes to wide contrast and deep black levels.
Only the very best LED LCD TVs that use full-array local dimming (FALD) backlighting can approach OLED TV performance. More typical LED LCD models often produce a black that is closer to charcoal gray.
Both LED and OLED are capable of reproducing HDR (High Dynamic Range) content.
Some people felt that the first OLED TVs were a little lacking in brightness, but current models are noticeably brighter. LED LCD TVs are brighter still because an LCD's backlight makes the entire screen brighter, not just the bright part of a scene.
Color accuracy is essential for a TV to produce a realistic picture. In general, color accuracy has been improving in recent years as TV makers have improved the color calibration process in their factories.
Both OLED and top-performing LED TVs typically have near-perfect color accuracy. Most newer 4K Ultra HD TV models feature WCG (wide color gamut) technology that allows them to reproduce a much wider range of colors than those specified by current HDTV standards. This extended color range is closer to what is used in movie theaters.
4K OLED TVs, and LED LCD models that use color-enhancing technologies like nanocrystals or "quantum dots," can reproduce this new wider color range. No video content currently supports this expanded color range.
Viewing angle is another area where OLED TV has a big advantage over LCD. When you sit directly in front of an LCD TV, the picture looks bright and colorful, but once you move to the sides or above or below the screen, brightness, contrast, and color become increasingly distorted or washed out.
Compared to LED-LCD TVs, OLED offers superior off-axis viewing. Picture contrast and colors remain vivid even for viewers sitting or standing off to the sides.
The culprit behind LCD's narrow viewing angle? Its backlight and the shutter effect of the screen's pixels.
OLED's self-lighting pixels completely eliminate this issue, so that picture quality even viewed from a severe angle is nearly as good as viewing directly in front of the screen. That's a major advantage if you often watch with others.
OLED TVs cost more than typical LED TVs, but that's not really a fair comparison because OLED delivers picture quality that's far superior. Only the very best LED TVs can produce a picture that comes close to OLED, and when you compare the prices of those models, they're similar to OLED.
LED TVs have been around for many years and have proven to be extremely reliable, typically providing many years of trouble-free service. OLED TVs have only been around a few years — not long enough for us to be able to predict their longevity.
Another thing to consider is that it's possible for OLED TV screens to experience burn-in if a static image is left on the screen for too long. But that's very unlikely to happen as long as you follow the manufacturer's guidelines.
Which type should you choose?
If you're looking for either a small-to-medium-sized TV or a mega-sized screen, you're probably going to end up with an LED TV because there's such a wide range of screen sizes to choose from. Likewise, if your top priority is bang for your buck, LED popularity means the prices are lower than OLED.
But if you're the sort of person who cares a lot about picture quality; someone who goes to the trouble of adjusting your TV to get the most accurate picture, you might find yourself focusing on OLED as well as high-end LED models. Both technologies can deliver spectacular picture quality.