LCD vs Plasma
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1. Introduction
2. Historical and irrelevant differences
3. Active differences
5. Summing Up
Introduction
Again I will start this guide by stating that this is an area of religious debate amongst techies. Meanwhile it is a popular topic at dinner parties. I will also state that we are an LCD only shop for more reasons than the technical capability of the screens.
On one hand this long standing argument is easier as technical advances have removed areas of difference. On another hand it is harder because that has equalised them somewhat.
Historical and irrelevant differences
Firstly we'll remove irrelevant comparisons, e.g. out of date arguments.
Viewing Angle
LCDs used to have appalling quality when viewed from an angle. This changed with the introduction of MVA and S-IPS technology (or S-PVA in the Sony/Samsung collaboration). Current flat panels viewing angles are all surprisingly clear right up to the point when you cant physically see the screen (180 degrees).
Refresh Rates
Plasma screens used to have the edge on being able to do fast image movement, but since LCD screens brought the pixel refresh rate down to 8ms and below this has become a mute point. The screen processor is now more significant in recreating quality movement than the panel itself.
Lifespan
In Plasma TVs the active phosphoric elements weaken and dull over time. The panel would need replacing, so the whole set is a write-off. In LCD screens the backlight can fade or tint over time. In theory the light is replacable, but the service infrastructure is yet to prove itself. By that age, this would probably be the trigger for a new TV of the latest specs anyway. Both sets quote 'half-lifes' of around double that of a CRT (by the time a CRT tube is expected to blow, the light emission from a flatscreen might have reduced by 25%).
Altitude
Being a gas based technology, Plasma can be effected by altitude, while LCD screens are relatively hardy in harsh conditions. As we are addressing the UK market, this is not considered a relevant issue.
Active differences
Image burn-in
LCD panels do not suffer from this problem. But Plasma panels can have a problem where static images on the screen for long periods can leave a burnt in image, like an electronic stain, on the screen. An example of this is where a TV is regularly on the same channel, the channel icon may get burned in. In the best of the latest plasmas the risk has been considerably reduced by better phosphoric elements and motion adaptive intelligence manipulating the static image (without you noticing). In cheaper models temporary burn in could be as low as 10 minutes of static image. Permamant burn in could be an hour.
Contrast Ratio / Black Levels
The contrast ratio of a panel is the measurement of the whitest whites to the blackest blacks, and is stated in a ratio form (eg 3000:1). There are various methods of measuring contrast ratio including "white screen to black screen" and "mixed black and white screen". Manufacturers make the most of vague testing sandards (creating untrustable numbers).
Plasma achieves black by simply not supplying voltage to a dark pixel element, rendering it dark or black. LCD screens use backlights while electrically un-twisting LCD crystals to block light to a pixel element, but its not 100%. They can dim the backlight for dark scenes, but can struggle with mixtures of light and dark on the same screen. Plasma manufacturers learnt years ago to control pre-voltage emisions on un-lit pixels to get excellent blacks. LCD has only with the very latest models been able to manipulate the LCD crystals to block light to plasma levels of black.
Many explanations for contrast ratio imply high ratios yield better details within shades (detail within a shadow, or texture on snow), which is a factor of grey-scale performance (luminescence), not contrast ratio. There is only one black and everything else is shades of dark grey. No panel can do perfect black, and beyond 1000:1 its pretty dark dark-grey all the way.
Reflections of the screens light back from the walls onto the panel can reduce 2000:1 to 500:1, or the difference between those numbers in a totally blacked room is barely discernible. Furthermore, the eyes dymanic response range ratio is in the low to mid hundreds (we can see a white cat in snow and shadows on a dark suit, but not shadows on a dark suit laying in the snow). Its marginal stuff and only an argument for a good quality calibrated panel and good cables in good light conditions, but not a long debate at dinner parties between the panel types using manufacturers bogus figures!!.
Brightness and Colour
Plasmas have good contrast ratios, and precise colour reproduction and and perform exceptionally in dim lit rooms such as home theatres, but can become a little washed out away from ideal lighting conditions.
Despite recent improvements, LCDs still lags slightly behind plasma in reproducing accurate colours (comparible to the source material), and many sets are left un-calibrated and over-bright. In the real world lighting conditions of our living room, LCDs can produce vivid realistic pictures in most conditions, and in many cases this is the key differentiator between them in LCDs favour.
Both Plasma and LCD will meet the requirement of most consumers.
Power
Plasmas sucks 200-300% more juice than LCD TVs, and at the larger end require professional installation to consider power suppky issues. So the environmental and economic argument is definately in LCDs favour, as well as the ease to get it home and turn it on with the minimal fuss.
Durability, Weight and Installation
Plasmas are notably heavier, notably more fragile, and amongst other things suck considerably more power. Generally it is recommended that plasma panels are shipped and installed by specialists. LCD screens being lighter, more durable and more electrically efficient, and are safer to self install.
Resolution and size
Do to the physical size constraints of the pixel elements there are limits to the size that a HD plasma can go down to. At around 40 inches an LCD will be a higher resolution (while both technically supporting HD Ready status). Meanwhile, its more difficult to make large LCD as the manufacturing process for the LCD substrate is prone to pixel defects on large screens. Therefore, while LCD is catching up Plasma in the larger sizes, LCD is still economiically stronger in small and medium sizes (up to 40 inch) and plasma in larger sizes (43inch and upwards)
Summing Up
When choosing between plasma and LCD TVs, you're actually selecting between two competing technologies which both deliver on the promise of sharp vivid images in a slim desirable package, and not a lot remaining to divide them to help you choose.
LCD will dominate small sets (because plasma can't compete there) and is catching up at the larger end of the market (>40"). For most individuals and families in British sized rooms the market increasingly expects the balance to tip towards LCD. Indeed, in 2006 several large manufaturers withdrew from Plasma. AV enthusiasts may argue for Plasma (just like car enthusiasts desire V12's that do 12mpg and cost £100000), but as arguably the better all-rounder and faster improving format, in British living rooms, the future looks bright for LCD. Oh, hang on a minute!! What are these SED and OLED technologies doing??
We hope this guide has been helpful
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