LCD vs. Plasma

Considering a flat-panel TV? The latest LCD and plasma HDTVs deliver outstanding picture quality, and both display technologies have improved dramatically over the past two years. 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. We'll also take a closer look later in the article at what happens inside each panel type to help you understand why you may prefer one over the other.

LED TVs such as the Samsung UN46EH6000 combine LCD display technology with LED backlighting to create bright, high-contrast images.

What about LED TVs?

So-called "LED TVs" have become really popular in the past few years. This is not a new display technology. LED TVs are actually just LCD HDTVs that use an LED backlight instead of a conventional fluorescent one. While the display technology is the same, LED-LCD TVs generally have better contrast and more accurate colors than fluorescent-backlit models. For more information, see our video on LCD backlighting.

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 LCD. Because of the difference in performance between fluorescent-backlit LCD TVs and LED-backlit models, we've separated them into two different rows.

Plasma

Pros: excellent contrast and black levels; effortless motion; good picture depth
Cons: not as power-efficient or thin as most LCDs; generates more heat than LCDs

LCD with  fluorescent backlight

Pros: panels weigh less than plasma and use less energy
Cons: picture slightly less natural and "filmlike" than plasmas

LCD with LED backlight

Pros: panels use the least energy and weigh less than plasma; models with local dimming capability can have black levels rivaling plasmas
Cons: picture slightly less natural and "filmlike" than plasmas

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 LCD. You'll also need compatible 3D glasses, either "active" or "passive" to match the type of 3D tv you have. And you'll need a source of 3D video, like a 3D Blu-ray player or 3D channels from your cable or satellite TV provider. For more info, see our intro to 3D, watch our video about 3D TV, or check out our in-depth 3D TV FAQ.

Viewing angle

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 LCD TVs than for plasmas. 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.

Picture contrast

Picture contrast is the difference between the brightest whites and the deepest blacks a TV can produce. It's an important performance spec — some 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 specs are most useful when comparing models from the same manufacturer.

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.

What you should know about picture contrast:

• "Native" vs. "dynamic" contrast ratio: Native contrast ratio (also called "static" or "on-screen" contrast) measures the difference between the brightest and darkest images a TV can produce simultaneously. Dynamic contrast ratio refers to the ultimate bright/dark range a TV can produce over time. A TV's dynamic contrast spec will always be higher, so TV makers prefer to list it. For more info, watch our video that explains picture contrast.
• LCD vs. plasma: Two ways to increase contrast ratio are to make whites look brighter, or blacks look blacker. LCD screens are typically brighter than plasmas, making them good choices for viewing in rooms with lots of light. Plasmas are known for producing deeper black levels, which makes them a smart choice if you do a lot of viewing with your room's lights dimmed or darkened. Some LED TVs can also achieve dramatic contrast levels. The most sophisticated type of LED backlighting employs clusters of LEDs which can be switched on and off independently. This "local dimming" approach represents the current state of the art for LCD picture contrast.

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 absolutely 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 LCD TVs, on the other hand, motion handling has traditionally been difficult 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.

How long do flat-panel TVs last?

TV makers don't mention longevity much anymore, but the last time we checked, both plasma and 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?

Plasmas generally offer slightly better contrast and black level performance than LCDs, along with noticeably wider viewing angles. People often describe plasma's picture quality as "filmlike," so it's a great choice for a home theater.

Plasmas can deliver a smooth, "filmlike" picture with impressive black levels. (Samsung PN59D7000 pictured)

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'll be sitting off-axis when you watch TV or movies.
• You want the smoothest, most natural motion with fast on-screen action, like sports or video games.

If you need a screen smaller than 42" or larger than 65", LCD is your only flat-panel TV option. LCD displays are very bright (brighter even than plasmas), so they can be better choices for more brightly lit rooms, including kitchens.

Today's LCDs are usually very energy efficient. (LG 42LM6200 pictured)

An 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 LCD's bright picture will be look better in bright light; some LCD screens also resist glare.
• Low power consumption is a priority — LCD TVs are usually more energy efficient than plasma models with the same screen size.

If you're interested in how plasma and LCD displays work, below we'll explain each one in detail.

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.