Flat? or Fat?
Digital televisions have completely changed the home entertainment viewing experience. Larger than life images captivate you in a home theater and televisions can now fit … just about anywhere. Amongst all this technology and jargon are a lot of variables to consider when picking out a new television. Here is a brief overview of the technologies behind today’s flat and fat televisions.
FLAT – Plasma
Most people know plasma TVs as those unbelievably thin display monitors that can be hung on your wall just like pieces of art. Even turned off, any plasma TV looks cooler than a projection TV. However, when it comes to technology there is nothing thin about plasma TVs.
Plasma displays function differently than any other TV technology in that they actually produce light independently at each pixel on the screen, as opposed to projecting a separate light source through, or off of other elements to conjure a picture. A plasma “screen” displays hundreds of thousands of individual cells, three for each pixel of the display (coated with red, green, and blue phosphors, respectively). Each cell is impregnated with a rare-gas mixture and connected to an individual electrode. When the electrode for a given cell is charged with an electrical voltage, the gas is converted to a plasma state and emits a burst of ultraviolet light; this in turn causes the phosphors to react and produce bright visible light at the pixel level. Each pixel cell is essentially an individual microscopic florescent light bulb, receiving instruction from software contained on the back electrostatic silicon board.
By varying the voltage and intensity of the electrical charge, the proper combination of red, green, and blue light is produced in each pixel to combine into a bright, colorful composite image.
A plasma TV will perform exceedingly well under most ambient light conditions. A very bright light does not “wash out” its picture, nor does backlighting cause a glare on the screen. Moreover, you can watch TV from almost anywhere in a room, since plasmas have a 178 degree viewing angle. Plasma’s accurate pixel structure produces a picture that is geometrically perfect from edge to edge and corner to corner, with uniform light output and a crisp, lifelike image. Plasma sets also offer superb color realism and exceptional gradations among colors. In fact, these color-saturated images are what give plasma displays an edge over other types of video displays in the eyes of many consumers.
Due to the direct way it produces light, plasma can be especially susceptible to burn-in from static images such as TV channel logos and video-game gauges. However, newer displays have begun to incorporate “pixel-orbiting” technologies that shift images, almost imperceptibly, to limit the occurrence of burn-in.
A plasma display is multi-functional and long-lived. Plasma display is a television monitor, capable of displaying HDTV, regular TV and home video. It’s also a computer monitor. The average life span of a plasma display is 30,000 hours (compared to 20,000 for a CRT). If watching a TV was your full time job and you did it 8 hours a day, it would take you more than a decade to wear out your plasma display. Plasma TVs are available in sizes from about 40 inches up to 70 inches plus. Keep in mind that not every plasma TV comes with a tuner or speakers. You may need to purchase a separate HDTV tuner and a separate speaker or home theater system.
The most obvious advantage to owning a flat panel television is an ultra-thin display (less than 6-inches deep). In addition to looking cool and sleek, flat panels might also be categorized as being part of the “space saving” age-they fit almost anywhere! Flat panels are versatile and can be placed on a stand or mounted on just about any flat surface, but before you envision one of them on the walls of every room in your home, be aware there are installation issues to consider. This often involves running cables and wires behind walls-something that should be done by professionals.
FLAT – LCD
Liquid Crystal Display (LCD) TVs use a screen similar to the type you’d see on a notebook computer. LCD TVs are true flat-panel displays that typically measure around 3 to 4 inches in depth and are lightweight enough to be mounted on a wall. The major advantage of an LCD TV is that they’re easier to watch. LCD displays are significantly brighter and feature higher contrasts than traditional CRT sets. An LCD TV will perform exceedingly well under bright light conditions. A brightly lit room won’t wash out its picture, nor will the lamp just behind your favorite chair cause a glare on your television screen. The beauty of these flat screens is that you don’t have to turn out the lights to see the image clearly and easily. Nor do you have to worry about eyestrain, since there is no flicker like your old-fashioned TV.
An LCD’s high brightness comes at the expense of deep blacks; hence, its typical contrast ratio cannot match those produced by direct-view or even DLP sets. Early versions of the technology had relatively slow “refresh rates,” causing slight but noticeable blurring or smearing of fast-moving images. Recent advances in LCD technology, like active-matrix TFT panels, have greatly improved performance. Likewise, technological improvements continue to reduce the occurrence of the “screen-door effect” caused by the distance between the pixels in an LCD display.
LCD-based big-screens use three high-resolution HTPS (High Temperature Poly-Silicon) LCD image panels, one each for red, green and blue. These are the more advanced “active matrix” type of LCD panels, in which each pixel is driven by its own thin-film transistor (TFT) etched onto the cell’s glass surface along with the electrical conductors. Each LCD panel may contain up to one million pixels or more. And the three panels are fixed in position, so they can’t go out of alignment.
Light from the high-powered lamp is split into isolated red, green, and blue beams using special “beam-splitting” mirrors. Because there’s a dedicated LCD panel for each primary color, excellent color is achieved without using a color wheel. Once the red, green and blue images are created, a prism combines them into a full-color image, which is projected through the lens.
Not all LCD TVs are high-definition (HD). Many are standard (SDTV) or enhanced (EDTV) depending on screen size and price. Plus, LCD TVs come in either standard (4:3) or widescreen (16:9) aspect ratios, so you can pick the screen dimensions that work best for your lifestyle. Many LCD TVs are compatible with multiple systems, like your PC, for example. Hook up an LCD screen to your PC and play your favorite PC game, answer emails or check out and share your digital photos. LCD TVs are available in many sizes, from 10″ standard-definition models to widescreen HDTV showpieces of 70 inches or more.
LCD strengths include great color and high brightness, plus resistance to screen burn-in from videogames or other types of sustained images. Their slim, sleek and lightweight designs allow them to be placed or mounted almost anywhere in the home, including places where you might not have considered placing a TV-like hanging from a kitchen cabinet or above the fireplace. They can easily be transported from room to room (with the exception of the largest screen sizes), and no matter where you put them, the latest models allow uninhibited viewing from angles as severe as 170 degrees off-axis.
FLAT – OLED
Organic Light Emitting Diode, or OLED, is a technology based on phosphorescence which is responsible for the glow that fireflies, plankton, and other underwater creatures emit. Kodak was the first to introduce phosphorescence to visual displays in the late 1980. Since that timeframe, competitors Samsung and Sony have worked to perfect the technology and manufacturability of OLED displays.
OLED is a low-power, fast responding and bright alternative to existing LCD and plasma flat panel technologies. With screens less than a millimeter thick, the potential this technology holds is almost limitless. From cell phones to PDAs to home theater sized displays, OLED seems the perfect display technology.
All technologies aren’t without their downsides. OLEDs happen to be price and lifespan (currently). Price is only an issue as the technology is still in its infancy. As more and more manufacturers adopt OLED, manufacturing costs will go down, eventually passing the savings to the consumer just as with LCD screens. An OLED’s lifespan is currently limited by the blue LED. Blue LEDs require significantly more power than green and red, thus reducing the overall lifespan of the TV to the lifespan of the blue LED – 14,000 hours, or roughly five years at eight hours of television per day. In 2007, experimental PLEDs (polymeric light-emitting-diode) were created which extend the life of the blue OLED to 62,000 hours, or 20 years at eight hours of television per day. So strides are being made to making OLED the display technology of the future.
If you require cutting-edge technology and the best of the best, Sony currently manufactures an 11-inch OLED TV with a $2499 MSRP. Several manufacturers are following suit, with shared hopes of bringing OLEDs as large as 40 inches to mass-market by 2011.
FAT – CRT
Often referred to as SDTV or Standard Definition Televisions, Direct-view TVs have a glass picture tube called a cathode ray tube (CRT). These traditional tube-type TVs still account for a large number of TVs in American homes. Their sharp, bright images provide a vivid viewing experience in virtually every room in the house. Sizes range from 12 inches up to 40 inches.
Recent technology changes include flat tube designs that deliver increased viewing angles and eliminate those traditional curved screen surfaces that caused glare. HDTV CRTs now have 16:9 widescreen flat tubes that give you full benefits of high-definition.
The main drawback to CRTs is their bulk, weight and deep cabinets. Today, consumers are finding other display types like flat-panel and shallow rear-projection TVs to be more appealing.
FAT – Rear Projection DLP
Digital Light Processing (DLP), developed by Texas Instruments, is a revolutionary new way to display and build rear projection TVs. The secret is in the DLP chip itself (about the size of an average postage stamp) and based around a proprietary semiconductor called a digital micromirror device (DMD). Packed onto each chip are a million individual mirrors.
Each tiny mirror is capable of moving thousands of times every second. When you shine a single light source on the DMD and move the mirrors, the light they reflect passes through a rapidly spinning color wheel that alternately filters it into red, green, blue and sometimes white or yellow spectra. By coordinating the mirrors’ modulations with the sequence of colors passed through the color wheel, the DLP light engine can create images with very subtle color variations, which are then magnified and projected onto a screen.
DLP-based projection TVs weigh much less and are not nearly as deep or bulky as their CRT ancestors. Most measure less than 15 inches deep and weigh less than 100 lbs. The bulbs (light source) on DLP TVs are cost-effective and easy to replace, allowing these sets to maintain their “like-new” brightness levels. The most recent innovation in DLP is LED. Using an LED lamp, response time and longevity has been significantly improved. LED DLPs last up to 60,000 hours, or over 20 years if you were to watch television eight hours each day. Because DLP chips are fixed in place, you never have to worry about convergence or focus adjustments. DLP projection TVs are also immune to image burn-in effects, so there’s no potential harm from stationary content such as video games, letterbox bars and station logos.
Due to the spinning color wheel some people may be sensitive to artifacts created by the spinning. This is commonly known as the “rainbow effect.” You can do some viewing tests on a variety of material to see if you’re sensitive to this effect; however, even if you are somewhat sensitive, it’s only prevalent in certain content. But it is a factor to consider when buying a DLP rear-projection TV. Viewers who are sensitive to this rainbow effect and find them distracted should seek a television without a color wheel such as 3-panel LCD, LCoS or HD-ILA models.
All in all rear-projection DLP may be a little higher priced than CRT models, but their superior video performance and sleek, thin design makes them worth it.
FAT – Rear Projection LCoS, SXRD, and HD-ILA
LCoS is the latest innovation in microdisplay technology. LCoS is short for “liquid crystal on silicon”, a hybrid of liquid crystal and reflective technologies. The secret behind LCoS technology is that it manages ultra-bright light to deliver high-contrast, sharply focused color images. Utilizing three reflective light imagers and a sophisticated prism and lens system, light is transformed into a laser-like beam and imprinted with a high-definition image. That image is then magnified and displayed in a perfectly aligned widescreen format. Because of this revolutionary technology, no consumer adjustments to improve focus or convergence are necessary. Brightness is also uniform across the entire widescreen, with the center of the screen and the far corners illuminated with precisely the same amount of light.
JVC refined the technology with its HD-ILA brand television displays. D-ILA utilizes a highly sophisticated form of 3-chip, vertically oriented LCOS (liquid crystal on silicon) technology that adds an inorganic alignment layer which both stabilizes the device performance and maximizes chip production. The result is superior resolution, grayscaling, brightness, and color reproduction when compared not LCD and DLPTM technologies. HD-ILA microdisplays make up JVC’s flagship television line-up.
Sony also produced its own LCoS variant, Silicon X-Tal Reflective Display, or SXRD. Sony’s design maintains a uniform, ultra-thin liquid crystal cell gap without any spacers in the image area. With such a small gap, SXRD technology produces superb contrast. Sony also uses a Vertically Aligned Nematic (VAN) liquid crystal that changes state with amazing speed. This enables Sony’s SXRD microdisplay to run as fast as 200 frames per second while minimizing image smear. The thin gap and VAN liquid crystal enable Sony’s SXRD technology to project images of a quality surpassing DLP projectors. For extended service life, Sony also incorporates an ultra-stable inorganic alignment layer.
From start to finish, JVC’s D-ILA technology and Sony’s SXRD are superior in almost every way to the other leading forms of microdisplay technologies.
FINAL THOUGHTS
So, what should you do? If television means a lot to you, skip the standard 4:3 CRTs and get a widescreen model, preferably a Full HD version (1080p), be it CRT, DLP, LCoS, plasma or LCD. The 16:9 screens are better for presenting DVD movies in their original wide format. With any of these sets, you can still watch standard television, and you are equipped for the ever-growing assortment of HDTV programming. Plus, getting a digital HDTV set will ensure that you can still receive all types of programming when broadcasters switch to digital transmissions in June 2009.
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