LED-LCD vs. Plasma
Which type of flat-panel HDTV should you buy?
LED-LCD TVs combine LCD display technology with LED backlighting to create bright, high-contrast images.
Considering a flat-panel TV? The latest LED-LCD and plasma TVs deliver outstanding picture quality, and both display technologies get a little better every year. Each type has a different set of strengths that make it more suitable for certain viewing situations.
In this article, we'll cover the pros and cons of each type, and explain some of the most common "tech-speak" in terms that will help you make apples-to-apples comparisons when you're shopping. You'll learn everything you need to know to figure out which flat-panel type is right for you. And if you'd like to dig a little deeper and learn how these skinny panels create such beautiful images, the second half of the article explains how the two technologies work.
Why we call 'em "LED-LCD" and not "LED" TVs
Some people mistakenly believe that so-called "LED TVs" use a new display technology. The term is frequently used by TV manufacturers and many retailers, but LED TVs are just LCD TVs that use an LED backlight instead of a fluorescent one. LED-LCD TVs generally have better contrast and more accurate colors than fluorescent-backlit models, and the LEDs are also very energy efficient.
At this point (6/13), nearly all LCD TVs from major brands use LED backlights, except for very basic models and TVs designed for outdoor use. For more information, see our video on LCD backlighting.
LED-LCD vs. plasma
If you poke around the Internet you'll find a ton of information (and some misinformation) about today's flat-panel TVs. The chart below provides a quick comparison of plasma and LED LCD.
|Plasma||42"-65"||Excellent||Very Good to Excellent||Excellent||Excellent||Good|
|LED-LCD||19"-84"||Good to Very Good||Very Good to Excellent||Good to Excellent||Excellent||Excellent|
- Pros: excellent contrast and black levels; effortless motion; uniform illumination over the entire screen area, good picture depth; often priced lower than LED-LCD models with similar screen size and features
- Cons: limited screen sizes: 42"-65"; some models not as bright as most LED-LCD TVs; not as energy-efficient as LED-LCDs and typically generate more heat; a plasma panel is usually a bit heavier and thicker than an LED-LCD panel
- Pros: models with advanced local dimming backlights can have black levels rivaling plasma; LED-LCD panels are thin and lightweight — especially models with edge-lit backlights; this is the most energy-efficient display technology
- Cons: picture may look a bit flat and less "filmlike" than plasmas; when viewed off-axis the picture may lose some contrast and color
Picture contrast is the difference between the brightest whites and the deepest blacks a TV can produce. It's an important performance spec — many experts consider it to be the most important. But because TV makers don't all measure contrast the same way, it can be difficult for shoppers to make meaningful comparisons between different TV brands. Contrast ratio specs have become so inflated in recent years that they're mostly meaningless, so we no longer list them.
The center example illustrates how good picture contrast combines deep black levels and natural shadow detail. The screen at left lacks deep blacks, while the right screen is too dark, obscuring details.
There are two basic ways to increase a TV's picture contrast: either make whites look brighter, or blacks look blacker. LED-LCD TVs are typically brighter than plasmas, while plasmas are known for producing deeper black levels. And for that reason we have tended to recommend LED-LCD TVs for use in rooms where the TV is competing with lots of other light sources in the room, like windows or lamps. Plasma's blacker blacks can be best appreciated in a room with the lights dimmed or darkened.
The reason plasmas excel at picture contrast is that each pixel — actually each subpixel — is self-illuminated, allowing very precise, controlled lighting. On the LED-LCD side, higher-performing models use sophisticated LED backlighting that can switch clusters of LEDs on and off based on the picture content. The general name for this ability is "local dimming." Originally, local dimming only referred to expensive high-end models that used a full-array backlight — a grid of LEDs that covered the back of the screen. Only a couple LED-LCD TVs still employ that technology, and local dimming is used to describe edge-lit displays that have a less precise but still effective form of dimming.
For more info, watch our video that explains picture contrast.
All flat-panel TVs have a great picture when you're sitting directly in front of the screen. But if your eyes aren't centered on the screen — you're viewing from off to one side, standing up, or lying on the floor — you may notice that the picture looks less bright and vivid, and you might see slight changes in color.
Viewing angle limitations are more of an issue for LED-LCD TVs than for plasmas. All LCDs use a backlight, and the LCD pixels act like shutters, opening and closing to let light through or block it. This shutter effect causes increasing variations in picture brightness as viewers move further off axis.
Smooth, clear on-screen motion
All 1080p HDTVs have the same screen resolution — 1920 x 1080 pixels — but they don't always deliver equal picture clarity. Most sets can display flawless still images, but moving objects on screen are more difficult to display cleanly. This can be especially apparent if you watch lots of things with fast action, like video games or sports.
Some TVs display onscreen motion clearly (left), while others may look blurry (right).
What you should know about motion handling:
- Motion handling has always been a strong point for plasma TVs. Because of the way plasma TVs create the picture, there's no lag or ghosting, and motion looks very natural and crisp. So if clear, true-to-life on-screen motion is a high priority for you, you should definitely consider a plasma.
- For LED-LCD TVs, motion handling has been more of a challenge because of the way they create the picture. But many of today's LCD TVs are better equipped to display fast motion without blur. If you want smoother motion with an LCD, look for a model with a 120Hz or 240Hz refresh rate. These sets include sophisticated processing that can virtually eliminate motion blur.
What type of TV do I need for 3D?
To watch 3D TV, you'll need a TV with a screen capable of displaying 3D video — it can be a plasma or LED-LCD. You'll also need compatible 3D glasses, either "active" or "passive" to match the type of 3D TV you have. For the most theater-like 3D experience, you'll need a source of 3D video, like a 3D Blu-ray player or 3D channels from your cable or satellite TV provider. But if you don't have a source of 3D content, you can still get a taste of 3D because nearly all current 3D TVs include built-in 2D-to-3D conversion. The feature adds a bit of 3D-like depth to regular 2D material. For more info, see our intro to 3D, watch our video about 3D TV, or check out our in-depth 3D TV FAQ.
How long do flat-panel TVs last?
TV makers don't mention longevity much anymore, but the last time we checked, both plasma and LED-LCD TVs from major brands have a rated lifespan of 100,000 hours. And that doesn't mean that if your TV reaches the 100,000-hour mark it will simply stop working. That number represents the estimated time when the TV's display panel will produce a picture that's only half as bright as when it was new. After the "half brightness" point the TV will still be usable, just somewhat dimmer.
But logging 100,000 hours of use takes a long time. If you were to watch for 6 hours a day, every day, it would take over 45 years! There are other parts in a TV other than the illumination component that could fail over time, but over the years the TV manufacturing process has grown more precise and consistent. The bottom line is that a new LCD or plasma TV should last at least as long as a typical tube TV.
Which flat-panel TV type is right for you?
Plasma's deep black levels, smooth motion, and vibrant colors produce picture quality than many people describe as "movie-like."
A plasma TV might be for you if:
- You like rich, warm colors and deep black levels.
- You do most of your viewing with low or modest room lighting.
- You or others will be sitting off-axis when watching TV or movies.
- You want the smoothest, most natural motion with fast on-screen action, like sports or video games.
Some LED-LCD models have an ultra-thin bezel which gives the screen an attractive virtually edgeless look.
An LED-LCD TV might be for you if:
- You want an ultra-thin TV — LCD TVs, especially LED-backlit models, tend to be thinner than plasmas.
- You do a lot of daytime viewing in a room with windows lacking blinds, curtains or drapes. An LED-LCD's bright picture will still look crisp and colorful in bright light; some LCD screens also resist glare.
- Low power consumption is a priority — LCD TVs are more energy efficient than plasma models with the same screen size.
How an LCD TV works
An LCD TV is sometimes referred to as a "transmissive" display. Light isn't created by the liquid crystals themselves; instead, a light source behind the LCD panel shines through the display. A diffusion panel behind the LCD redirects and scatters the light evenly to ensure a uniform image.
The display consists of two polarizing transparent panels and a liquid crystal solution sandwiched in between. The screen's front layer of glass is etched on the inside surface in a grid pattern to form a template for the layer of liquid crystals. Liquid crystals are rod-shaped molecules that twist when an electric current is applied to them. Each crystal acts like a shutter, either allowing light to pass through or blocking the light. The pattern of transparent and dark crystals forms the image.
The multi-layered structure of a typical LCD panel. Because they use red, green and blue color filters in place of phosphor dots, LCD TVs are completely immune to screen burn-in.
LCD TVs use the most advanced type of LCD, known as an "active-matrix" LCD. This design is based on thin film transistors (TFT) — basically, tiny switching transistors and capacitors that are arranged in a matrix on a glass substrate. Their job is to rapidly switch the LCD's pixels on and off. In an HDTV's LCD, each color pixel is created by three sub-pixels with red, green and blue color filters.
An important difference between plasma and LCD technology is that an LCD screen doesn't have a coating of phosphor dots (colors are created through the use of filters). That means you'll never have to worry about screen burn-in, which is great news, especially for anyone planning to connect a PC or video game system.
How a plasma TV works
A plasma TV is sometimes called an "emissive" display — the panel is actually self-lighting. The display consists of two transparent glass panels with a thin layer of pixels sandwiched in between. Each pixel is composed of three gas-filled cells or sub-pixels (one each for red, green and blue). A grid of tiny electrodes applies an electric current to the individual cells, causing the gas (a mix of neon and xenon) in the cells to ionize. This ionized gas (plasma) emits high-frequency UV rays, which stimulate the cells' phosphors, causing them to glow the desired color.
Each individual plasma cell is switched on and off by its own electrode. A plasma HDTV can have up to 6 million cells.
Because a plasma panel is illuminated at the sub-pixel level, light output is very consistent across the entire screen area. Plasmas produce the widest horizontal and vertical viewing angles available — pictures look crisp and bright from virtually anywhere in the room.
Because plasma TV screens use a phosphor coating like CRT-based TVs, the possibility of screen burn-in exists, though it's unlikely to happen with current models. To reduce the chance of burn-in, be sure to follow the manufacturer's recommendations on setup and use.