- Audio & Video
What's better? LED or Plasma?
The Ultimate TV debate: LED or Plasma? Which is the best?
Which is best, LED or Plasma? This question turns up a lot especially when someone you know is looking at buying a new TV. So, I thought I would open up a can of worms with this one. A very debatable topic, one which I hope will get a lot of people talking about the advantages and disadvantages of the two more expensive types of HD TV's, LED's and Plasma's. Let me point our that there is no definitive answer to this question, unless you specified your use for said TV.
What are LED TV's?
Before discussing what the best is, I thought it prudent to introduce what each type is, so that people who have only just heard of LED's and Plasma's can join the debate.
Firstly, let us understand the acronym, LED. I'm sure the majority of us already know what the letters stand for, but for those that don't, they stand for Light Emitting Diode. Can you guess what they are used for in a TV yet? Perhaps not, especially if you were unaware of how a regular LCD TV works, so let's go into that quickly.
An LCD (Liquid Crystal Display) is a screen made up of a liquid crystals, unsuprisingly. The liquid crystals themselves do not emit light but have very unique modulating properties allowing them to be used perfectly as visual displays. The crystals are positioned in front of a backlight, which is usually positioned directly behind the liquid crystals, or slightly to the side. Unfortunately with LCD's, the backlight is just one light source, with only light valves to moderate the amount of light going through the display. As a consequence, LCD's tend to be the worst for picture quality, especially colour and shadow detail.
An LED display is an upgraded LCD, the display is still made up of liquid crystals however the backlight is no longer just one source. The backlight is now made up of LED's, all of which can be individually controlled, to let just the right amount of light through. Although termed LED TV's they really should be called LCD TV's with LED backlighting, however, it is a bit of a mouthful.
Firstly, there are two types of LED's; white LED's and RGB LED's. Again another acronym, RGB, means Red, Green, Blue. White LED's tend to be the more common, however, they are not nearly as good as RGB LED's when producing different shades of colour.
Secondly, there are two types of LED backlighting; Edge-Lit LED Backlighting and Local Dimming LED Backlighting.
LED TV's on Amazon
Edge-Lit LED Backlighting
Edge-lit is exactly how it sounds, the LED's are arranged at the edges of the panel, use white LED's, and with the aid of what is called a light diffusion panel, spread light to the centre of the screen. They also allow for extremely thin TV's, less than 1 inch in depth!
Local Dimming LED Backlighting
Local Dimming is where the entire panel behind the liquid crystals is covered in LED's, all of which can be individually controlled or dimmed. Without this local dimming, placing an array of LED's behind the entire panel would be the same as a regular LCD.
What are Plasma TV's?
In the field of solar physics, scientists use the term plasma as a reference to ionised gas. In a Plasma TV display, there are many so called 'chambers' or fluorescent lamps containing electrically charged ionised gas. These chambers contain a small amount of mercury as well as an array of inert noble gases. When the mercury is vaporized and a voltage is applied across the cell, the gas in the cells form a plasma. With flow of electricity, some of the electrons strike mercury particles as they move through the plasma, momentarily increasing the energy level of the molecule until the excess energy is shed. Mercury sheds the energy as ultraviolet (UV) photons. The UV photons then strike phosphor that is painted on the inside of the cell. When the UV photon strikes a phosphor molecule, it momentarily raises the energy level of an outer orbit electron in the phosphor molecule, moving the electron from a stable to an unstable state; the electron then sheds the excess energy as a photon at a lower energy level than UV light; the lower energy photons are mostly in the infrared range but about 40% are in the visible light range. Thus the input energy is shed as mostly heat (infrared) but also as visible light. Depending on the phosphors used, different colors of visible light can be achieved.
Plasma TV's from Amazon
A panel typically has millions of tiny chambers between two panels of glass. Each pixel in a plasma display is made up of three cells comprising the primary colors of visible light. Varying the voltage or current to the chambers thus allows different perceived colors.
LCD vs LED vs Plasma
So, which is better?
I will now try to answer this question, taking into account the following important aspects of a TV's attributes.
- Picture Quality
- Sound Quality
- Appearance and Design
- Energy Consumption
Possibly the most important part of a TV is the quality of the images you see on the screen, well, that and the price. Looking into the technology of the two types, there really shouldn't be too much difference between them. TV gurus tend to define a TV's picture quality to be dependant on its ability to produce inky blacks, great detail in shadows, bright whites, and whether or not image quality remains at different viewing angles. The ability of an LED to produce these tones should be quite simple, turn them all off when you want to produce the deep blacks and turn them all on for the whites. Unfortunately, as the screen size gets larger, this simple trick doesn't seem to have the expected effect.
Plasmas on the other hand, have no problem producing inky blacks and their images do not suffer from degradation at higher viewing angles. They also seem to cope better with fast moving imagery, showing almost no motion blur whatsoever. On the other hand plasmas screens are rarely made below 35 inches and the obvious reason is that the difference between them and LED's at smaller sizes is negligible. Another point to note is that in the earlier plasma screens, the displays were susceptible to screen burn caused by having the same image on the screen for too long. Although modern plasmas have taken precautions to prevent this, the problem, whilst less noticeable is still present.
In summary: Plasmas are the best overall for picture quality although for TV's with screen sizes of less than 35 inches, LED's are just as good. Also, whilst plasma's show better initial picture quality, over time the degradation of the phospors due to screen burn can cause their lifespan to be cut short.
The sound quality of a TV does not seem to be inherent of the screen type, it is more a matter of the design and shape of the TV plus, of course, the speakers themselves. As the quality of the speakers tends to be more a brand issue, I won't go into them here, although one should note that as plasmas tend to be larger and more expensive, they usually get the better speakers, although with an increased power consumption.
As for the design aspect, thinner TV's tend to comprimise the size and ability of the speakers within them. Thus, as LED TV's are notoriously slimmer, they seem to lack somewhat in the sound department.
In summary: Plasma sound quality rules!
The energy consumption of a TV was never really an issue 10 years ago, although that may have been because LED TV's and Plasma TV's were yet to be commercialised. Nowadays, it seems very important and with the ever increasing fuel prices, who's surprised? That being said, LED's are extremely economical, sometimes twice as energy efficient as similar sized plasmas.
In summary: LED's win!
Appearance and Design
An ever important attribute in any market especially technology, the look and feel of an object can be the buying or selling points, more so than the specifications. Whilst the name "plasma" sounds cool and there is no denying the glass finish is superb, the slimline LED's have just got the edge when it comes to the sleek and stylish look.
Arguably the most important point in the buying of a new TV, the cost of LED's and Plasma's have become intertwined. Whilst Edge-lit LED's are cheaper than plasmas, local dimming (full-array) LED TV's are not always. A few years ago, there was no doubt the most expensive was plasmas, but since the invention of local dimming LED's, this is no longer as clear-cut.
Buying a Plasma or LED
So, we have learnt that Plasmas tend to offer better picture and sound quality although are potentially less reliable. Whilst LED TV's have a lower energy consumption and look better. With just these facts, to me the question of which is the better TV is easily answered; Plasma's. However, one should always take into account what the TV will be used for, the size, and the make. Some plasma models are so poorly manufactured that an LED is undeniably better, and for example, if you are buying a 30 inch TV, then an LED is usually cheaper and offers just as good picture quality.
I am very interested in what everyone has to say, so if you have anything you would like to add to this, or you have recently bought a plasma or LED, or have experience with either one, I would really appreciate you commenting and adding your thoughts to this discussion.