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LCD Vs Plasma TVs - Which is the best?

Most people are not aware of the difference between LCD televisions and Plasma televisions. Quite often people will refer to a flat panel tv as a Plasma tv or an LCD tv incorrectly as a generic term. What is the difference? What are the advantages of LCD TVs or Plasma TVs?

LCD tv or Plasma tv - Which is the best ?
by Armadeus Cornelius

Are there any differences between the two technologies?

Most people are not aware of the difference between LCD televisions and Plasma televisions. Quite often people will refer to a flat panel tv as a Plasma tv or an LCD tv incorrectly as a generic term. e.g. a 26 inch Plasma tv, a size of Plasma tv that doesn't exist. What they actually mean is a 26" LCD screen. So what are the differences between them and how do you spot them? Both flat panel technologies can be hung on the wall and can produce unbelievably realistic images that make you feel that you are there.

How LCD tvs work

The LCD tv screen is a thin flat display device and is made up of a two clear panels which have many colour liquid crystal filled pixels that are arranged in arrays in between them. When a small voltage is applied to the crystals they twist or untwist repositioning themselves so that light can either pass through or it is blocked. When millions of crystals do this a picture is displayed. Very little power is used in this process. Behind the screen is a back light that illuminates the pixels and displays a colour depending on their colour (either red, blue or green), also areas of light and dark spots are displayed depending on how they are positioned. LCD devices are available in small sizes for items such as a watch up to 108 inches. Most television manufacturers produce LCD television including Hitachi, JVC, LG, Panasonic, Pioneer, Philips, Samsung, Sharp, Sony, and Toshiba.

How does a Plasma television work ?

The screen of a Plasma tv is made up of millions of microscopic gas filled glass cells which have electrodes in them. The cells are filled with inert gases including xenon and neon and form each pixel. When a current is applied to the cell electrodes the gas atoms become 'excited' and become a plasma emitting photons of ultraviolet light. When the photons strike the phosphor coating that is inside the glass cells light is emitted. The light colour emitted is determined by which of the three coloured phosphors are used - Red, green or Blue. These colours can be combined to produce billions of colours. When millions of the pixels are combined they form an image on the screen like LCD televisions. Plasma tvs are only manufactured by Panasonic, Philips, Pioneer, LG, and Samsung and are available in range of sizes from 32 inches through to 150 inches.

Performance and Picture quality compared

Brightness

LCD TVs can be brighter than plasma TVs. This perception of this brightness is of course dependent on where the TV is located and what is being watched. In reality both technologies are capable of producing a level of brightness that is in excess of what is required in normal viewing.

The effect of the Contrast Ratio and the Black Levels.

This is a measure of the difference of the luminosity of the brightest white on the screen and the darkest black. So a contrast ratio of 3000:1 means that the brightest white is 3000x brighter than the darkest black. Details can be more easily differentiated the higher the contrast ratio is as long as the the black levels aren't 'grey'. Previous models of LCD tvs had lower contrast ratio than plasma tvs because the pixels weren't able to block the back light for dark areas and the light would leak through making the image lighter. Improvements in technology have reduced this leakage so that the contrast ratio is much closer to those of plama tvs. But ultimately plasmas are able to produce blacker blacks because the pixel cells are able to be switched off instead of blocking the light as lcd tvs do. The blacker the black on a tv the better the picture quality it is able to produce. The colour saturation or colour palette is affected if the blacks aren't black enough . When the black level on a plasma is compared with the black level on an comparable priced LCD tv, the plasma tv black often makes the LCD tv black look grey.

Colour Saturation

This is a measure of the accuracyof the colours on the screen based on the existence of grey shades - the higher grey shades results in lower colour saturation. Plasma TVs have high colour saturation due to the way they emit light. The capability of Plasma tv pixels to be turned off when they are not in use prevents the emission of stray light that diffuses colour. This is why tints and hues on Plasma TVs are noticeably more vivid and vibrant

The Colour Gamut

Is the breadth and amount of colours that can be displayed. The most costly models are now claiming to have colour gamut's getting fairly close to the full spectrum for plasma tv and LCD tv. In fact most plasma TVs have a propensity to be better than most LCD tvs except the top of the range ones. With the cheapest LCD tv models usually offering a colour gamut that isn't as good the higher LCD tv models. So usually the plasma tv has the best colour gamut.

Screen Resolution

This is the quantity of pixels that make up the screen. The higher the resolution is, the higher the definition and the sharper picture is. Currently, LCD HDTV's create the image at 1920 pixels x 1080 pixels, full 1080p resolution at a lower cost than plasma tv panels of the same size. There is no difference in an HD LCD tv or Plasma tv for screen sizes above 37 inches. However plasma tv screens of 37 inches and below are currently only HD Ready but LCD tv models are available from 32 inches upwards in full HD or 1080P.

Response Time and Refresh Rate

The combination of these two characteristics affects how a screen can handle fast moving pictures without blurring. The gauge of how quickly a screen can change when an input signal is received is the response times. In the past motion blur on LCD tvs was caused by slow response times where the pixels took too long to change state from, on to off, and back on to refresh an image. The latest models of LCD tv screens have improved pixel response times that now mean that actual response time is no longer the cause of motion blur. The main cause is now the frame rate refresh rate.

All LCD tvs and Plasma tvs have until of late had frame rates of 50 frames per second or 50hz. The more costly LCD tv and Plasma tv models now have 100 Hz to compensate for any motion blur. Since the standardsignal is only 50 Hz the additional frames are created with signal processing software which interpolates what the extra middle frames should look like. The result is moving pictures that loose little to no definition and are more fluid. The best Plasma tv screens nonetheless respond better to fast motion than LCD tv but the variation has lessened as the best LCD tvs motion response time has improved and 100hz and 200hz has been introduced.

The Viewing Angle

Pictures on plasma TVs are nevertheless clearly viewable at about 160 degrees and on some models up to 180 degrees. However the picture dulls further than about 100 degrees.

The screen surface of lcd tvs and plasma tvs

LCD tv screens are available with matt finish screens which reduce glare while Plasma tvs have a reflective screen.

Image Burn-in

This can result if a static image is displayed on the screen for a prolonged time, and even after the image is changed or removed, the 'ghost image' of the previously displayed static image is still noticeable on the screen for the rest of the screens life. burn-in doesn't occur on LCD tvs. But the expose of burn-in on plasma tv is usually exaggerated and unlikely.

Image retention

Many people mix up burn-in with image retention which is very similar. With image retention the 'ghost image' disappears quickly either as soon as a new, bright image is displayed or after a few seconds. Image retention is infrequently noticed but normal on plasma tvs because of the technology used, but it can be minimised by having a 'break-in' period as soon as the plasma tv is first purchased. The break-in period as a rule lasts 100 hours, during this time you should not view any programs that do not fill in the whole screen, and you shouldn'tview any programmingthat have static images such as bright station logos or news scrolls at the bottom of screens, and you ought to decrease the contrast and brightness to a middle point. Now there are also features built in to the plasma tvs to reduce the possibility of either burn-in or image retention.

Is there any difference in power consumption of LCD tvs or Plasma tvs ?

The backlight on an LCD tv is constantly on so the power consumption is almost constant. By manually adjusting the brightness of the back light up or down the power consumption is either increased or decreased. The twisting and untwisting of the LCD pixels consumes hardly any power.

Because Plasma TVs charge the gas in the individual pixels to a plasma to create the light, and the more light that is required on a scene the more energy is used. So pictures with low brightness in them use less energy, and high brightness more energy i.e. the power consumption varies.

The energy requirements that are quoted for Plasma tvs are for full brightness settings. The effect of this is that lcd tvs seem to use less power than plasma tvs. But the power consumption of a plasma tv varies depending on the amount of dark and bright areas on the displayed image. Studies have found that when the viewed programs are mainly dark or on movies the amount of power consumed for plasma tvs will be lower than an lcd tv. However when the viewed programs are sports and cartoons the power consumption for plasma tvs is greater than on lcd tvs. When varied programs are viewed the power consumption is similar for LCD tvs and Plasma tvs. Future plasma tvs are going to consume less than half the amount power consumed at present.

Plasma tv Life expectancy

It is common myth that is quoted that plasma tv screens don't last very long. However manufacturers such as Panasonic are quoting a life expectancy of 100000 hours which is 11.5 years of continuous use. Therefore any concerns are unsubstantiated

Conclusion

Both technologies have advantages. Plasmas tvs generally have a superior subjective picture with healthier black level, higher contrast, and superior colour rendering than LCD TVs. Though LCD TVs have higher brightness, freedom from screen burn-in worries, and are lighter and thinner. This is not always the case becausea good LCD TV can have a better picture than an average or poor plasma TV. But on balance I think that a plasma tv is the better option with more advantages. In the end you get what you pay for so spend as much as you can manage to pay for on you preferred format.

For the finest advice and the best discounts with the finest service go to Save Money on LCD tv's and Plasma Tv's. If you want to save even more money check out the Clearance sale of LCD tv's and Plasma tv's.

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