subject: Choices: LCD vs. Plasma vs. LED [print this page] Choices: LCD vsChoices: LCD vs. Plasma vs. LED
Flat-Panel TV Choices: LCD vs. Plasma vs. LED
While there was intense debate when LCDs and plasma displays were introduced, LCD proved to be the definitive winner over the past few years. (That said, plasma TVs are still available and there are good reasons for owning one, which we'll describe below.) But the recent introduction of LED TVs, with their smaller form factors and increased dynamic color ranges, brings another angle to the debate. Hopefully this article will help you make sense of the different arguments.
The Short Answer: The short answer is that we think LCD is a better choice now because of the wide availability of full 1080p resolution sets at reasonable price points. You will usually have to pay more for a 1080p LCD than for a 720p plasma of the same size, but much less than the cost of a comparable LED. While plasma does offer a great picture with fantastic color and contrast, we think its higher power consumption and lower resolution makes plasma HDTVs less desirable than the latest generation of LCDs. And while LED is a compelling choice for its size and improved color range over conventional LCDs, the increased cost over LCD and cost of some picture detail to achieve that dynamic color range means that LCD, for the moment, makes the most sense for the most people.
When discussing the pros and cons of LCD vs. Plasma vs. LED, we think these are the key areas to look at:picture quality,price, andpower consumption. Image quality is the hardest to understand so we'll focus the most explanation there.
Picture Quality: When trying to gauge the picture quality a flat-panel HDTV is capable of producing, attributes and features to consider are contrast ratio, resolution, panel response time, refresh rate, and the image processing involved. There are no easy answers for whether plasma, LED, or LCD wins at any one of these measures. Because the image processing involved can have such a big effect on the other features, any two panels of the same size and year from two different manufacturers could have vastly different performance. Whichever you choose, we highly recommend top tier brands as these companies are furthest ahead in new processing technologies for improving picture quality. LCD brands we recommend areSony,Samsung,Sharp,Toshiba,Mitsubishi,Hitachi,Philips, andJVC. Plasma brands we recommend areHitachi,Panasonic,Pioneer, andSamsung. LED brands we recommend areLG,Panasonic,Sony,Samsung, andVIZIO.
Contrast Ratio: Contrast ratio measures the difference in light and dark tones a panel can produce. A higher contrast ratio means more subtle details in an image will become apparent-so this is a good thing. It can be measured either statically or dynamically. A static measure is one taken with a single still image on the screen (generally in black and white), and a dynamic measurement involves color and moving image and creates an average. Manufacturer information should say whether the contrast ratio they give is static or dynamic, but usually they don't. When you see really high contrast ratios listed, these are typically static measurements. In the past LCD panels have had a lower contrast ratio than plasmas because they use a backlight system which tends to bleed through darkened pixels and lighten the image, but the recent crop of LCDs from major manufacturers have much better contrast ratios that are more competitive with Plasma. LEDs, which are actually LED-backlit LCDs, lie somewhere in between, improving the dynamic contrast ratios available over conventional LCD but still lagging slightly behind the contrast quality of plasma. Measured fairly apples to apples, and viewed by most observers, plasma still has an edge in contrast ratio, though it is now a pretty slim one.
Resolution: The whole point of HDTV is getting higher resolution than standard TV. Currently you can find flat-panel HDTVs in 720p, 1080i, or 1080p, with 1080p being the highest resolution available. These numbers refer to the number of vertical lines, and whether they are drawn progressively (all at the same time) or interlaced (in two passes). The other thing to look for is the full pixel resolution including the vertical and horizontal, typically displayed as 19201080 (for full 1080p). All three display types are currently capable of producing true 1080p resolution. For now, resolution isn't as much of a deciding factor as it used to be, but that will change in the coming years as the HDMI spec gets more refined.
Response Time and Refresh Rate: These two attributes work together to determine how fast a moving picture a panel can reproduces without blurring the image. Response time measures how fast a panel can make changes on the screen from the time an input is received. It used to be the case couple years back that LCD panels had slow response times, and response time was the limiting factor causing motion blur on these sets. That's because LCD technology requires each pixel to go from an on state, to an off state to back on in order to refresh an image. Panel response times have by now been improved enough that the actual response time is no longer a limiting factor, and to the extent that motion blur still exists with LCD sets, it's a function of the refresh rate, or the frame rate.
LCDs have until now had frame rates of 60 frames per second, which is the same rate found in native SDTV and HDTV signals. Today, main manufacturers of LCD and LED HDTVs all produce high end lines of panels with a 120 Hz refresh rate that makes up any motion blur gap LCD may have had in the past. Since the signal itself is only 60 Hz (or frames per second) the additional frames are filled in with signal processing software which interpolates what the extra frames should look like. The results, when ideal, are moving pictures that lose little to no definition at all. To get this new technology, you'll have to pay more for an HDTV. For now, Plasma has a slight margin over most LCDs and LEDs for motion response.
More about Frame Rates: It's generally accepted by most viewers that film images look better than TV images. In one key respect, TV actually has an advantage over film, and that is in the frame rate. TV and video signals (both SD and HD) use a frame rate of 60 frames per second, whereas film is all shot at 24 frames per second. A problem arises when you convert content shot on film for viewing on TVs or HDTVs. To fit the 24 frame per second content into the 60 frame standard of TV, a process called 3:2 pulldown is used. Some frames get duplicated 3 times, and some get duplicated 2 times to make the fit. Without some really good image processing to interpolate intermediate steps and remove artifacts, this process can result in jerky movement. Advances from couple of the big HDTV manufacturers address the problem in a couple different ways. One way will be to eliminate 3:2 altogether and offer TVs capable of a 24 frame setting which can detect film originated content, remove the 3:2 duplicate frames and display the content in 24 frames just like you were watching a film. Another method uses interpolated frames instead of 3:2 duplicates to produce a smooth transition between frames, and still show at the great 60 frames per second.
Image Processing: Flat-panel HDTVs don't just take a signal and send it straight to the screen. They run all sorts of image processing on it first, that is designed to enhance some of the attributes above, and fill in any gaps in the transition that may have occurred. Good image processing typically does scaling work on content that's not full 1080p, converting it to 1080i. A 720p set will use software to down-convert the original 1080i signal by half, and then upconvert that to 720p. A full 1080p set will process the 1080i signal, doubling it to make it display progressively. To the extent that HDTV manufacturers give good explanations and images depicting what all their processing does for the image, we try to include that on individual product detail pages. We don't give an edge in this department to either LCD or Plasma, but for good image processing, we highly recommend sticking with the list of brands mentioned above as these all take image processing very seriously, and the quality of the software used can have a big impact on the final picture you get.
Price: Nothing changes faster in HDTV than price. The truth is, LCD is fast becoming the technology of choice at screen sizes 52-inches and below-Plasma's traditional territory. To compete, plasma prices came way down, and we don't forsee them going back up. Currently there are incredibly good deals to be had on 42-inch and 50-inch 720p plasma HDTVs from top brands like Panasonic, Pioneer, Samsung, and Hitachi. For a little more money you could opt for a full 1080p LCD HDTV at a slightly smaller screen size. In the short run, expect the plasma companies to do their best to give LCD stiff competition on price. For now LEDs are a new enough technology that they're not price-competitive with LCDs, so LCDs are still provide the best balance between features and price.
Power Consumption: Because LCD uses a backlight system and closes pixels off to produce darkness, the power consumption of an LCD HDTV is constant whether the image is bright or dark. LEDs are so named because they're actually LCD TVs that use LEDs for the backlights, which offer 20-30% lower power consumption and better contrasts over regular LCDs. Plasma panels produce more brightness by pumping more energy into each cell or pixel that needs to be brightened, and it turns down the power to cells that need to be darkened. As a result, plasma power consumption varies with the brightness of the picture. For most content people tend to watch, Plasma HDTVs tend to use more power. It is true that plasmas are likely to use less power displaying dark scenes, or movies that are dark in general, but averaged out; plasmas do tend to use more power. Even with recent efficiency improvements in plasma technology, plasma HDTVs will tend to consume a third more power than the same size LCD HDTV. In power consumption, LEDs are definitely the winner here.
Screen Burn-in: One complaint about plasma technology has been that still images left on the screen can burn in and leave a ghost image. This was problematic especially for things like video games which tend to keep a stationary score counter on the screen, or sports on TV that tend to keep a box up with scores and stats. In recent years the major plasma manufacturers have introduced new technology to prevent this from happening, and burn-in is no longer a real issue in our view.
High Altitude: Because plasma technology depends on gas compressed in tiny cells, people living at very high altitudes have reported issues. The problem is that as the air pressure goes down the gas in each pixels cell expands, and no longer behaves a intended when power is supplied. Complaints have ranged from strange whistling or buzzing noises emanating from the plasmas, all the way to TVs not displaying correct color. The first thing to note when you read about high altitude and plasma, is that the effects only happen at high altitudes, and by high, we're talking about higher altitudes than Denver Colorado, the highest altitude city in the US. Unless you are way up in the mountains, this is not going to be a problem for you at all and should not be a deterrent to choosing plasma.For all but a small handful of households in the US, this is a non-issue.
