Comparison of progressive and interlace scanning

The advantages of progressive scan are:

• Higher vertical resolution than interlaced video with the same frame rate. The perceived vertical resolution of displayed video is traditionally adjusted using a Kell factor coefficient. This coefficient has no fixed value and depends on display device. Its value for interlaced video is usually lower than for progressive video, when the same display device is used. When interlaced video is compared to progressive video with the same number of scan lines, interlaced video delivers lower perceived vertical resolution at a lower frame rate.
• Absence of visual artifacts associated with interlaced video of the same line rate, such as interline twitter.
• No necessity in intentional blurring (sometimes referred to as anti-aliasing) of video to reduce interline twitter and eye strain. In the case of most media such as DVD movies and video games, the video is blurred during the authoring process itself to mask flicker artifacts when used on interlace displays. As a consequence, recovering the sharpness of the original video is impossible when the video is viewed progressively. An excellent, but rarely employed countermeasure to this is when display hardware and video games come equipped with options to blur the video at will, or to keep it at its original sharpness. This allows the viewer to achieve the desired image sharpness with both interlaced and progressive displays. An example of a video game with such a feature is Super Smash Bros. Melee, where a “Deflicker” option exists. Ideally it would be turned on when played on an interlaced display to reduce interline twitter, and off when played on a progressive display for maximum image clarity.
• Offers much better results for scaling to higher resolutions than equivalent interlaced video, such as up converting 480p to display on a 1080p HDTV. Scaling works well with full frames, therefore interlaced video must be deinterlaced before it is scaled. Deinterlacing can result in severe “combing” artifacts.
• Frames have no interlaced artifacts and can be used as still photos.

However, the only disadvantage of progressive scan is that it requires higher bandwidth than interlaced video that has the same frame size and vertical refresh rate.

Example of interlace scanning field

Interlaced scan refers to one of two common methods for “painting” a video image on an electronic display screen by scanning or displaying each line or row of pixels. This technique uses two fields to create a frame. One field contains all the odd lines in the image, the other contains all the even lines of the image. A PAL based television display, for example, scans 50 fields every second (25 odd and 25 even). The two sets of 25 fields work together to create a full frame every 1/25th of a second, resulting in a display of 25 frames per second.

The interlaced scan pattern in a CRT (cathode ray tube) display completes such a scan too, but only for every second line. This is carried out from the top left corner to the bottom right corner of a CRT display. This process is repeated again, only this time starting at the second row, in order to fill in those particular gaps left behind while performing the first progressive scan on alternate rows only.

Such scan of every second line is called interlacing. A field is an image that contains only half of the lines needed to make a complete picture. The afterglow of the phosphor of CRTs, in combination with the persistence of vision results in two fields being perceived as a continuous image which allows the viewing of full horizontal detail with half the bandwidth that would be required for a full progressive scan while maintaining the necessary CRT refresh rate to prevent flicker.

Interlace is a technique developed for improving the picture quality of a video signal primarily on CRT devices without consuming extra bandwidth (bandwidth is a cost, higher bandwidth require more data storage). Interlacing causes problems on certain display devices such as LCD TV. It was invented by RCA (Radio Corporation of America) engineer Randall C. Ballard in 1932, and first demonstrated in 1934, as cathode ray tube screens became brighter, increasing the level of flicker caused by progressive (sequential) scanning. It was ubiquitous in television until the 1970s, when the needs of computer monitors resulted in the reintroduction of progressive scan. Interlace is still used for most standard definition TVs, and the 1080i HDTV broadcast standard, but not for LCD, micromirror (DLP), or plasma displays; these displays do not use a raster scan to create an image, and so cannot benefit from interlacing: in practice, they have to be driven with a progressive scan signal. The deinterlacing circuitry to get progressive scan from a normal interlaced broadcast television signal can add to the cost of a television set using such displays. Currently, progressive displays dominate the HDTV market. Only CRTs can display interlaced video directly – other display technologies require some form of deinterlacing.

Broadly speaking, Progressive video will look better on an LCD TV because these panels are progressive in nature. Any Interlaced content is converted on the fly to Progressive (it ‘fakes’ a progressive picture, which never looks as good as a real progressive one).

1080p is the shorthand name for 1,080 lines of vertical resolution progressive scanning signal (1080 horizontal scan lines). The letter p acronym for progressive scan. 1080p can be referred to as Full HD (Full High Definition) to differentiate it from other HDTV video modes (example, HD Ready LCD TV). The term usually assumes a widescreen aspect ratio of 16:9, implying a horizontal resolution of 1920 pixels. This creates a frame resolution of 1920×1080, or 2,073,600 pixels in total. The frame rate in Hertz can be either implied by the context or specified after the letter p, such as 1080p30, meaning 30 Hz.

Common Video Resolutions (1080 / 720 / 480)

1080p is sometimes referred to in marketing materials as “Complete High-Definition”. However, 2K/4K digital cinema technology is commercially available, and ultra-high definition video is in the research phase.

In addition to the meaning of 1080p as a display resolution, 1080p is also used to describe video equipment capabilities. Use of 1080p and the closely related 1080i labels in consumer products may refer to a range of capabilities. For example, video equipment that up-scales to 1080p takes lower resolution material and reformats it for a higher resolution display. The image that results is different from the display of original 1080p source material on a native 1080p capable display. Similarly, equipment capable of displaying both 720p and 1080i may in fact not have the capability to display 1080p or 1080i material at full resolution. It is common for this material to be downscaled to the native capability of the equipment. The term “native 1080p capable” is sometimes used to refer to equipment capable of rendering 1080p fully.

Contrast Ratio Comparison Between LCD TV

Many LCD specifications are prone to inflation by the manufacturers or have become largely meaningless. Take contrast ratio for example. That’s the white level divided by the black level, and if you could actually get pure black on any LCD contrast ratio would be “infinity”. In practice, anything over 500:1 is sufficient, and 1000:1 is about the best you can see before the manufacturers start playing tricks. What sort of tricks? How about dynamic contrast ratio, where the backlight intensity changes according to the content currently being shown on the display.

Comparison of Contrast Ratio

Now you can take the maximum white level at maximum brightness and divide it by the minimum black level at minimum brightness, which results in substantially higher contrast ratios. Unfortunately, in practice the varying intensity of the backlight can be distracting to say the least, and color accuracy greatly suffers because of the constantly shifting brightness levels. Our advice: ignore dynamic contrast ratios, and if your display supports the feature we recommend disabling it.

Pixel response times are another area that has been inflated — or deflated in this case. We have looked at various LCDs boasting anywhere from a 2ms to 16ms response time; honestly, we would be hard-pressed to tell the difference between most of them. All of the comparison images we’ve captured show similar best/worst case scenarios for pixel response latency, with one or two afterimages present. A bigger problem these days is processing lag (aka “input lag”), which is the delay between the time a signal is sent to your LCD and the time the internal circuitry finishes processing it and actually shows it on the LCD panel. We have measured lag as high as 50ms, which makes gaming very frustrating and is even noticeable/irritating during general Windows usage.

Sharp claimed they are number one LCD TV brand in Japan. Now, Samsung can claim they are number one TV brand worldwide. Samsung was the global brand share leader in revenues for the eleventh straight quarter, holding their revenue share nearly unchanged at 22.5%, more than 9 points higher than #2 Sony. Samsung’s 36% Y/Y growth was the strongest among the top five brands. Samsung also had the top ranking on a unit basis and led both LCD and MD RPTV (Rear Projection Television) categories on a unit and revenue basis with #2 rankings in CRT and PDP. Sony was #2 on a revenue basis for the fifth straight quarter and had the second strongest Q/Q growth among the top five, picking up about a point of share from Q2 to Q3.

LGE remained #3 even though their share was down about a half a point to 10.9% on a revenue basis. LGE led in global CRT shipments. Given the technology’s strong position in emerging markets, this made LGE #1 in emerging markets on a unit basis. Complete review of the top five brands can be seen in the following table:

TV Market Share Compare By Brand

LCD TV still hold the top TV technology for televisions market. Surprisingly, CRT TV still continue holding a big portion (42.7%) of market share, it contribute by emerging market. LCD TV shipments rose to nearly 27 millions units with North America maintaining its position as the largest LCD TV market. Majority of LCD TV shipments were 32 inch, which hold a 36% share of all LCD TVs in Q3’2008, while the 40 inch+ share was unchanged from Q2 at about 27%. For complete breakdown of worldwide TV shipments by technologies can be seen in the following table:

Worldwide TV Share By Technology

Data source: DisplaySearch.com

Funai
Funai might not be a household name because it’s the brand behind other brands, mainly lower-priced labels such as Emerson, Sylvania, and Symphonic, that tend to be sold at mass-market stores, such as Wal-Mart. Funai recently acquired the rights to two longtime TV brands, Philips and Magnavox, in the U.S. and Canada (Philips will no longer be making and selling its own sets here). It’s possible that Funai will use those brands, particularly Philips, to gain entry into retailers that don’t carry its other brands.

Haier
Established in America in year 1999. Today, it a tier one brand that competitive with Panasonic, LG and Samsung for electrical appliances. Their LCD TV products range from low-end to high-end for all sizes.

Hewlett-Packard
After forays into rear-projection and plasma, Hewlett-Packard—often known as HP—now sells LCD TVs exclusively. Leveraging its PC heritage, the company is in the forefront of TV interactivity, offering models with MediaPC capability and Internet connectivity.

Hitachi
Hitachi, at one time a leading rear-projection TV manufacturer, now focuses exclusively on flat-panel HDTVs. The company has been strong in plasmas, sometimes offering unusual sizes (such as a 55-inch screen) and resolutions (1024×1080). It previously had a limited LCD line, but it is making a strong push into LCDs with a line of ultra-thin 1.5-inch-deep LCD TVs.

Insignia
Insignia, Best Buy’s electronics house brand for LCD TV and Plasma TV, is exclusively sold by the retailer. Insignia TVs, which are made overseas by contract manufacturers, are positioned as a “value” line offering more features for the price than better-known makes.

JVC
The company’s LCD sets are typically positioned in the mid-to-upper price range. JVC recently signed a deal with Funai to jointly develop and produce LCD TVs. It recently exited the LCoS rear-projector microdisplay business, but continues to make LCoS-based front projectors for the consumer and professional markets. JVC is in the process of merging with Kenwood, a consumer electronics company known largely for car audio products.

LG Electronics
LG is a growing force in the plasma and LCD categories, remember the Scarlet line? Often, the company offers the largest screen sizes available for each type. The company’s newer TVs have had a strong design focus. LG sets typically sell in the mid- and upper price brackets.

Mitsubishi
In LCD TV, Mitsubishi is positioning its sets as a premium line with step-up features (all models are 120Hz, 1080p sets, for example) and ultra-slim bezels for select dealers. The company’s flagship line is the Diamond series. Mitsubishi is one of two major brands (the other is Samsung) still actively selling rear-projection micro-display (DLP) TVs. It is promoting models with 3D technology, and this year will introduce the first set (dubbed Laser Vue) using a laser as a backlight. In the front projector market, it has competitively priced 3LCD-based high-definition (720p and 1080p) models.

Olevia
Olevia, previously named Syntax-Brillian, recently sold its LCoS rear-projection TV business to focus on LCD TV market. It has three distinct lines of LCD TVs: very basic sets value-priced compared with the competition, a step-up series line, and a flagship series that includes additional features.

Panasonic
Panasonic is the market leader in plasma TVs (Panasonic is major plasma TV manufacturer), with an extensive line of sets ranging from 37 inches to 58 inches. Plasma sets are usually competitively priced and are widely available, including at CostCo. The company is also expanding its assortment of LCD TVs this year. Its apparent strategy is to offer LCDs in smaller (37 inches or less) screen sizes that won’t compete with its plasma TV lines. Panasonic is getting out of the rear-projection market, selling off its existing inventory, to focus primarily on flat-panel TVs, which carry the Viera brand. It also sells 3LCD front projectors.

Philips
Philips, which exited the plasma business to focus on LCD models, recently announced that it will be licensing its Philips and Magnavox brands to Funai for use in the U.S. and Canadian markets. As a result, Philips- and Magnavox-brand LCD TVs will be made and sold by Funai, which also controls the Emerson, Sylvania, and Symphonic brands. Philips had used the Magnavox brand for its entry-level products aimed at mass-market retailers.

Pioneer
Plasma stalwart Pioneer has consistently targeted consumers willing to pay more for a “prestige” label, particularly with its higher-priced Elite-brand series. The company offers a line of performance-oriented Kuro plasmas, which are typically priced much higher than its competition. The company recently announced that it would no longer make its own plasma panels but would instead source them from Panasonic (though it will continue to apply its other proprietary technologies to the TVs). In addition, a recent investment in the company by Sharp could result in the first Pioneer-branded LCDs.

Polaroid
Polaroid is a value brand that is often among the lowest-priced sets of its type and size. Polaroid’s TV presence in the U.S. has expanded thanks to increased shelf space at Circuit City and Wal-Mart. Polaroid TVs are made overseas, primarily in China and Taiwan, by contract manufacturers. The Polaroid brand was acquired in 2005 by a former U.S. licensee, Petters Group, which had previously used the brand for TVs and DVD players.

Samsung
Samsung is a top-tier manufacturer in every category in which it participates, and is one of two major brands—the other is Mitsubishi—still making rear-projection microdisplay (DLP) HDTVs. Samsung is often an innovator, as with its use of LED backlighting in rear-projection and LCD TVs, and 3D capability in rear-projection and plasma TVs. Samsung has value-priced and premium lines.

Sanyo
Sanyo’s focus is largely on LCDs TVs and front projectors, though it still has one plasma model. Its flat-panel TVs are sold primarily through Wal-Mart, typically at lower prices than sets from first-tier manufacturers. In front projectors, the company’s 3LCD models compete with entry-level HD models from companies such as Epson, Panasonic, and Optoma.

Sharp
Sharp is a force in LCDs and has been at it longer than almost any other manufacturer. The company sells its TVs under the Aquos brand. It has one of the most advanced LCD panel manufacturing plants in the world and is often an innovator. Like many other major brands, its lines are segmented into several different series. Some of Sharp’s biggest, most innovative sets are pricey; others are competitively priced. The company recently took a stake in Pioneer; the benefits to Sharp are likely to be audio related.

Sony
Sony is a powerhouse LCD TV manufacturer with one of the most extensive product lines of LCD sets, which are sold under the Bravia name. There are several distinct Bravia lines with varying levels of features and quality; most are mid- to high-priced, and its flagship XBR-series models are generally the most expensive of their type. Sony recently started offering a low-priced line for mass merchants such as Target and Wal-Mart. Sony has exited the rear-projection microdisplay business (LCoS), but continues to make front projectors for the consumer and professional markets.

Toshiba
Toshiba, which sells LCDs under the Regza label, has some sets that emphasize value, with features comparable to those of other major brands, but generally at lower prices. Its Cinema Series models are higher priced and loaded with features. The company, which makes LCD TVs in a large range of sizes, has a new line with very thin bezels, allowing a larger screen size to be used in a smaller physical space.

Vizio
From its humble start just a few years ago as a warehouse-only brand, Vizio has emerged to become a top-tier TV brand whose sets are now also available in Wal-Mart and in some Circuit City and Sears stores. Vizio TVs, which are made overseas by contract manufacturers, are generally sold at very low prices compared with more established names, but the company has announced some new models that will carry higher prices and some step-up features.

Westinghouse
Westinghouse Digital, which licensed the venerable brand from Westinghouse Electric, has emerged as a lower-priced alternative to more established LCD brands. It has typically been among the first to offer step-up features such as 1080p resolution at lower prices than its competitors.

May be you spent some time looking over the Sunday circulars from Best Buy, Circuit City, and other major retailers. Perhaps you spent some time on the internet, shopping around for the bets price. You may even have read a few product reviews here and there.

It’s also probable that, like your fellow shoppers, you aren’t quite sure exactly what the difference is between LCD and plasma. Sure, they’re both flat. One seems to be brighter than the other, but a little washed out at times. Some are marked HDTV, you might know what that means, but what does “EDTV” mean?

Panasonic 150-inch plasma TV

Is your new flat-screen TV going to “burn-in”, “burn-out”, or “burn-up”? Just how long will it last before you have to replace it? Does the gas leak out of a plasma TV? Will sunlight hurt your LCD TV?

And just who are all of these companies selling LCD and plasma TVs? Sure, you’re heard of Sony and Samsung, Panasonic and Philips, Polaroid and Toshiba. But who the heck is Maxent? Funai? Ovideon? Syntax? Vizio?

For us journalists, covering the fast-growing market for plasma and LCD TVs can be a real challenge at times. For consumers, it can be frustrating, confusing, intimidating, and expensive. There are an awful lot of products to choose from, but they’re not all “created equally”. Nor do they offer the same resolution and connector options.

In the interest of clearing up some of this confusion, I’ve prepared a list of things you should know about plasma and LCD TV technology, and some shopping tops to take along when you are searching for the ‘perfect’ flat screen TV. You know the old saying – ‘forewarned is forearmed!’

The Facts on Plasma

Both plasma and LCD technology are ‘mainstream’. Numerous companies sell these TVs in a variety of sizes, and prices are dropping faster than an elevator with a broken lift cable. Because of increasing consumer demand (and the fact that the United States is the #2 market worldwide for TVs), plenty of companies have gotten into the game.

Here’s something you should know. In the plasma market, there are only a handful of companies that actually manufacture plasma TVs. Not surprisingly, these companies typically have the best image quality and the broadest line of products available.

In Japan, Panasonic, Pioneer, and Hitachi are the ‘Big Three’ in the plasma manufacturing. Panasonic is rolling out about 100,000 panels a month in 37-inch EDTV, 42-inch EDTV, 42-inch HDTV, and 50-inch HDTV sizes. They also have a new 65-inch model coming to market. Pioneer manufactures 43-inch HDTV and 50-inch HDTV plasma TVs using their original assembly line, and 42-inch, 50-inch, and 61-inch products on the ex-NEC line they purchased in January of 2004.

Hitachi also cranks out various sizes of plasma in the FHP factory that was originally a joint venture with Fujitsu. (Fujitsu recently announced they were withdrawing from the plasma manufacturing business). Hitachi panels sold in the United States include 37-inch and 42-inch HD ALiS (Alternate Lighting of Surfaces) designs, and a unique 55-inch HD plasma TV.

In Korea, Samsung SDI is the clear leader with about 250,000 panels a month flying off their assembly line. Samsung manufactures 42-inch EDTV, 42-inch HDTV, 50-inch HDTV, and 63-inch HDTV plasma TVs for the mainstream market. (An 80-inch model is also set to debut recently). Neighbor LG Electronics is active with 42-inch, 50-inch, 60-inch, and even 71-inch products.

In China (Taiwan), Chunghwa Picture Tube (CPT) is rolling out 46-inch EDTV and HDTV plasmas, based on older Mitsubishi designs. Aside from the odd startup here and there, your plasma TV will use ‘glass’ from one of these six manufacturers, even if it has a different name on the front plate.

Certain sizes of plasma TV screens are as unique to a company as a fingerprint, such as 43-inch (Pioneer only), 55 inches (Hitachi only), 61 inches (Pioneer only) and 63 inches (Samsung only). If you see one of these with another brand name on it and a higher price, you may simply be paying a premium for that brand, or there may actually be some added value, such as improved video processing and sealing.

Keep in mind that true HDTV resolution can’t be found in plasma TVs smaller than 50 inches. There are two HDTV broadcast standards – 1920×1080 interlaced (1080i), and 1280×720 progressive (720p). So, in order for a plasma TV to be considered truly ‘HD’, it should have at least the same amount of pixels as a 720p signal, or more.

‘HD’ in smaller sizes of plasma means that there are more pixels than ‘ED’ plasma, but generally not as many as there are in a true HD display. So, you’ll find that it’s difficult to see any substantial difference in picture quality between these two types of plasma TVs, particularly when viewing an HDTV program.

When viewing a widescreen DVD, you may often be surprised to see that the less expensive EDTV plasma TV actually looks sharper than the more expensive HDTV plasma TV! That’s because the image resolution of a widescreen DVD (nominally 704×480) is very close to the actual pixel count (852×480) in EDTV plasma.

I would venture to say that if you watched both of these plasma TVs with the same content on them from a reasonable viewing distance – say, eight feet to ten feet – you might think the extra money for the same-size HDTV version isn’t really worth it. And you’d be in good company, as 42-inch EDTV plasma TVs were big sellers during the 2004 holiday season, while 42-inch HDTV plasmas were not.

The bottom line? Think about where you’ll put your plasma TV, how far you’ll be sitting from it, and what you’ll be watching on it most of the time. If you’ll be sitting eight feet or more from a 37-inch or 42-inch plasma TV, you’ll probably be quite happy with an EDTV version.

Even though the picture is not HDTV, you’ll find that HDTV programs still look spectacular and noticeably more detailed than standard programming. Of course, if you plan on sitting real close to the TV or are buying a larger screen size, then HDTV is the way to go.

Now to address a few concerns about plasma: First of all, today’s plasma TVs don’t have the same problems with premature image aging (burn-in, burn-out) that plagued older plasma monitors and TVs. That’s because the mix of gases used in the panels have been changed to improve longevity. You’ll hear the figure “60,000 hours” thrown around; be conservative and figure half that, which is 30,000 hours.

30,000 hours is the equivalent of watching eight hours a day of television, seven days a week for 10 years. I don’t watch that much television, but perhaps you do. Assuming you operate your plasma TV in the ‘Normal’ or ‘Cinema’ picture modes and don’t play video games on it too often, you should be in fine shape for quite some time.

Wall Mounted Plasma TV

No, you don’t need to recharge the gas in the panel – it can’t leak out, and besides, you’d need a laboratory-grade facility to reseal it if it did develop a leak. Yes, you can hang plasma on the wall, but don’t put it upside down on the ceiling! Most people prefer to simple place it on a stand, and for the smaller sizes, you don’t really need to pay anyone to install it for you – a screwdriver and a couple of strong bodies will do the trick.

Yes, some plasma TVs make a lot of noise at high altitudes. That noise is the mechanical ‘buzz’ created during the plasma’s on-off imaging cycles. At low altitudes, the air pressure is sufficient to keep the glass from vibrating very much. But at high altitudes, air pressure is lower, so the glass vibrates more – and you hear it.

The Facts – LCD Television

There are a number of companies manufacturing both the LCD panels used in these TVs and the finished TVs themselves. In Japan, the clear market leader is Sharp Electronics, who offers a wide range of sizes from under 20 inches to 26-inch, 32-inch, 37-inch, and even 45-inch LCD TVs. In Korea, Samsung SDI and LG Philips produce large quantities of LCD panels in sizes as large as 55 inches, and Samsung, LG, and Philips all retail them as finished TVs.

Sharp 108-inch LCD HDTV

In Japan, Hitachi, NEC, Kyocera, Sanyo, and Panasonic have all manufactured smaller LCD TV screens at one time or another. In China, a host of companies are cranking out LCD TV products including Chi Mei Optoelectronics, AUO, and Chunghwa Picture Tube in sizes to 46 inches.

Your TV is going to come from one of these companies, but it’s a little harder to tell exactly which one than it is with plasma. The LCD market goes through cycles of panel oversupply and undersupply quite frequently, and trading companies who wholesale to US retailers constantly shop around to get the best price for their latest models.

As with plasma, the companies who make the largest quantities of LCD TVs (Sharp, Samsung, and LG with partner Philips) typically have the best picture quality. You’ll also see higher prices for these brands than you will with the dozens of “who’s that?” brands out there.

That doesn’t mean the “who’s that” brands are to be avoided. A new player in the market, Kreisen, recently announced 37-inch and 40-inch LCD TVs with analog tuners that use LG and Samsung LCD panels, but at greatly discounted prices from those brands. (Kinda like buying a generic version of a drug at Walgreens).

Unlike plasma TVs, all widescreen LCD TVs over 15 inches in size have true HD resolution (usually 1280×768 pixels, sometimes more). Bigger models starting at 46 inches and up actually have 1920×1080 pixel resolution, but they command quite a price premium at the moment.

LCD TVs don’t suffer from ‘burn-in’ or ‘burn-out’ like plasma panels do. They can, however, have ‘stuck’ or dead pixels. The leading manufacturers have higher standards for defective pixels, so you can usually purchase from those companies with confidence that you won’t see white, black, red, green, or blue dots on your TV programs that won’t go away (and if you do, your warranty offers some protection).

Although plasma TVs can generate extremely bright images, they have an automatic brightness governing system to keep them from doing so with high luminance program material so as to avoid burn-in and premature phosphor aging. LCD TVs have no such braking system and will usually make a much brighter image on the showroom floor and in your home.

Because plasma TVs employ phosphors for imaging, they are susceptible to glare from indoor and outdoor light. LCD TVs don’t have this problem; they create images by shuttering light through tiny color filters and generally handle annoying reflections from open windows or nearby lights with no difficulty.

What LCD TVs don’t have is deep, rich black levels. On average, the level of ‘black’ measured on the best LCD TVs is about 10 times as high as that measured on the best plasma TVs. Also, colors on LCD TVs don’t appear to be as rich (or even accurate) as a plasma TV. As a result, you will probably find that LCD TVs seem to look better under normal room lighting, but plasma TVs excel when the lights are turned down.

LCD TVs are expected to last between 50,000 to 60,000 hours, and that’s usually the time it takes for the backlight to burn out. However, you should read the fine print in your owner’s manual. Those life expectancy numbers are not for full brightness, but only 50% or even 25% of full panel brightness (tests have been done to confirm this).

The upside is that LCD TVs are available in so many sizes that you can put them just about anywhere you’d wish in your house. I’ve used 15-inch and 17-inch sizes as HDTV displays in my downstairs bathroom each year during the Super Bowl!

Samsung 1cm LCD TV

LCD TVs, as a general rule, use less power than plasma (25% on average) and also weight less in equivalent screen sizes (about 20% on average). And they are slightly thinner too, although when you are talking about TVs that measure only 3” to 5” in thickness, who really wants to split hairs?

Conclusion

Both plasma and LCD TVs can be a welcome addition to your home. It’s up to you to read the myriad of reviews available in print and on the web so that you can make the right choice. And don’t obsess over rapidly falling prices. If you are ready to buy and have picked out the right type and size of TV for you, enjoy it with the knowledge that you did your homework and made an informed buying decision!

Related post: Comparison of LCD TV and Plasma TV

Article by: Peter Putman

Defective Pixels (Hot Pixels, Dead Pixels, Stuck Pixels)

LCD Display Pixels With 3 Sub-Pixels

Defective pixels plague almost every brand of LCD televisions manufacturer like top brand Sony, Samsung, Sharp and LG. The LCD monitors in your office desktop, or laptop LCD monitors might have defective pixels problem too. Each pixel consists of three sub-pixels, which are red, green and blue. Each sub-pixel can be controlled independently to yield different combination of color. All the pixels arrange side by side and control the color of each pixel individually, and a whole bunch of well arrange pixels in order yield an image on the LCD television screen panel. Defective pixels can be categorizing to three type, which are hot pixels, dead pixels and stuck pixels. A hot pixel is a pixel which always on, or called glowing pixel. Hot pixels are usually best seen against dark background. Dead pixel, it opposite of hot pixel, always off (or unlit). Dead pixels are usually best seen against a white background, it just looks like a black dot in the white. However, stuck pixel is one or two sub-pixels are always on or always off. This defective behavior make the pixels only limited to display limited colors and it hardly to be notice except you test through your LCD screen panel.

Banding

The backlight has a problem with particular area, or it may be certain area from the LCD panel not well lighted. It can be describe as the backlight of LCD TV panel not equally lighted all area with the CCFL backlight. A band like bar will appear on the LCD panel that look different tint or tone that you can notice.

LCD TV with Banding Problem

LCD TV with Banding Problem

From photos above, there are three banding appeared on the LCD panel screen. No matter the panel screen display of bright color or dark color, you still able to notice the banding clearly. Blog from John-Michaeldelvalle.com (john-michaeldelvalle.com/2008/09/08/lcds-problems-you-should-know-about/) pointed that this is common issue for Sharp brand LCD televisions.

Clouding / Mura

LCD TV with Clouding Problem

Clouding is complete uneven backlighting that result in an image contain lots of black cloud on the screen. This is extremely difficult to assume that it is a common problem without evaluating multiple consignments of the same product. A search on the internet found that clouding problem affecting Sony XBR series (example: 46XBR3, 40XBR2), and a lot of Sony Bravia KDL-46V2500 46-inch LCD TV model.

Clouding Problem (From Sharp LCD TV)

Pillaring

Pillaring is another uneven backlighting problem that similar to clouding but not exactly the same. Pillaring is when you have the complete left and right side of the LCD screen being lit up a lot more than the center of the screen. The word “pillaring” because it is as if there is a pillar of light on each side of the LCD screen.

LCD TV with Pillaring Problem