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Display Technology: Comparing LCD, LED and Plasma, along with other display options

Posted by Eric Smith on

Display Technology

-When you're shopping for an HDTV, there are plenty of factors to consider. Chief among them is the type of display. Fortunately Boxy, bulky CRTs are long dead and mammoth rear-projection HDTVs are all but extinct. The HDTV market is currently dominated by three distinct choices in display technologies: Plasma, Traditional CCFL-backlit LCD, and LED-backlit LCD. For years, the question of which technology reigned supreme has remained unanswered. In the early days of HDTVs, plasma, with its inky blacks and top-notch picture quality, was the prevalent flat-panel technology, especially among videophiles. Gradually, thinner, more energy-efficient LCDs with CCFL backlighting became less expensive and more capable and started gaining ground. The difference between plasma and LCD wavered for some time, with each offering different economic and visual benefits depending on the model, price, and time in the life cycle of HDTVs. But in the past couple of years, with the advent of increasingly sophisticated LED backlighting along with huge advancements in Plasma technology standard LCD has taken a clear back seat with regard to performance and desirability within consumers. With its unmatched energy efficiency, and performance level with a wide array of program material LED-based LCD is a clear all around choice in HDTV technology. Unfortunately, it's also generally the most expensive. (Though LED HDTV prices have come down considerably over the past year, and continue to drop all the time). If it's in your budget, the choice is clear: Pay the premium over LCD and get an LED-lit HDTV. In many cases the choice may be dictated by your required screen size as manufacturers offerings for LCD have skewed to the smaller sized sets. What's the Difference Between LCD, LED, and Plasma? -The three technologies are vastly different, particularly in the method in which the screen is lit. In plasma HDTVs, the phosphors that create the image on the screen light up themselves, and don't require any backlighting. This creates a very even and accurate white level along with the widest viewing angle of all display types. For LCD HDTVs, however, the liquid crystal screen does not illuminate, requiring a separate light source. That's where the difference between "regular" LCD screens (also known as CCFL-backlit LCD) and LED-backlit LCD screens (also known as LED-LCD, or just LED screens) come in. Traditional LCD HDTVs use cold cathode fluorescent lights (CCFLs) to illuminate the screen. CCFLs are similar to the fluorescent lights you might see in your lamps and overhead light fixtures. They use a charged gas to produce light. LED-LCD screens, like their name implies, use light emitting diodes (LEDs) to illuminate the display. Several factors can be influenced by the type of HDTV display you choose. Among them, and the most prominent are screen thickness, brightness, darkness, energy efficiency, and price. Ideally, you want an HDTV that's affordable, paper-thin, can get face-of-the-sun-bright and black-hole-dark, and consumes less than a watt. That's currently impossible, but LED-backlit LCD HDTVs can come closer than the other two technologies. For this advantage, LED HDTVs command a premium; for all major HDTV manufacturers, LED-backlit HDTVs can cost a few hundred dollars more than CCFL-backlit HDTVs of the same size. Generally, plasma HDTVs tend to be the least expensive, priced at equal to or slightly less than CCFL-backlit HDTVs. However, that savings means the screen will usually be somewhat thicker and more power-hungry, even if it does offer as good a picture as an LED-backlit HDTV (Although some new high-end models offer thinness in line with LED!). LED HDTVs don't have to be super-expensive, but they almost always cost more than their CCFL-backlit and plasma counterparts. Considering the excellent picture quality and significant benefits in screen thickness and power consumption, that extra amount on the price tag is well worth it. Image Quality -How good the picture looks, especially if you're a Videophile or a cinema fanatic, is the most vital aspect of any HDTV. Specifically, peak white and black levels determine how detailed a picture can look on a screen. Poor white levels mean fine details can get washed out in bright scenes, while poor black levels mean shadows swallow up parts of the picture in dark scenes. A very wide gamut from dark to light lets the HDTV show the tiniest details, regardless of how bright or dark the movie gets. Historically, plasma HDTVs have produced the best black levels, which is always beneficial when viewing film-based material that contain dark scenes and images. White levels don't matter quite as much as black levels, because it is more difficult for screens to show fine details in shadows and easier to crank out very bright whites with backlighting, but they can still matter. At this, LED backlighting benefits with their superior overall brightness. Size and Power -Screen thickness isn't the most important aspect of an HDTV, but initially, it's the most noticeable. A super-thin HDTV is not only visually striking, but it's more easily mounted on a wall, and can be more readily arranged, displayed, or concealed as part of your home theater. At this, LED lighting wins hands-down over LCD. The CCFLs that backlight standard LCD screens are much thicker than LEDs, and plasma screens require a fair amount of room for the actual plasma cells (Although these are now changing to thinner designs). LEDs, on the other hand, can be extremely tiny while being extremely bright, meaning an array of LEDs along the edge of an LCD can light it up while completely removing the backlight from the equation (in this configuration, the LEDs are considered "edge-lighting," not backlighting, though the term backlighting can cover all screen illumination). Some LED HDTVs are so Svelte, you can literally fit three units into the space of an LCD model of the same screen size!. Energy efficiency is an important factor when choosing an HDTV, and between the three technologies LED-backlit HDTVsis the most “Green” of the three. LED HDTVs consistently consume around 100 watts or less, while plasma HDTVs can eat up two or three times as much. OTHER TECHNOLOGIES LED / LASER based Rear-projection DLP -This Display type was introduced early in 2002. Due to continued improvement in flat-screen technology DLP production has officially ceased. OLED TV What is OLED? -An OLED TV screen uses a new display technology called OLED (Organic Light Emitting Diodes). OLED televisions are brighter, more efficient, thinner and feature better refresh rates and contrast than either LCD or Plasma. A little bit about the technology: -OLEDs are made by placing thin films of organic (carbon based) materials between two conductors. When electrical current is applied, a bright light is emitted. The OLED materials emit light and do not require a backlight (unlike LCDs). Each pixel is a small light-emitting diode, in fact. OLED TV panels offers several advantages over LCDs: • Faster refresh rate, better contrast and better color reproduction • Thickness: the LG's EL9500 for example is just 1.7mm thick. We've seen prototypes of OLED televisions that are merely 0.3mm thick! • Better viewing angle - almost 180 degrees • Greener: OLEDs draw less power, and contain no bad metals • Potentially lexible or transparent... True-OLED vs OLED-with-color-filters -While a True-OLED TV uses 3 color OLED sub-pixels (Red, Green and Blue) to create each 'pixel', some companies are using a different architecture that uses white OLEDs with color filters (OLED-CF). These kinds of OLED TVs will be less efficient, but might be easier -Samsung plans to build a Gen-8 pilot production line for OLED TVs, according to recent reports from Korea. They want to produce 55" OLED panels, and the pilot line will be able to produce 4,000 such panels monthly. Samsung will use the same building as used in their upcoming 5.5-Gen production plant. In September, Yoon Boo-keun, the head of Samsung's TV business unit said that "It's too premature to commercialize OLED TVs due to strong price resistance, while Brian Berkeley, Samsung's OLED R&D VP said that OLED TVs are "coming soon". We'll have to wait and see what Samsung plans for us..”.

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