Any shopper who is interested in a pure flat TV will no doubt face the question. The question will be more prominent when LCD TV s and LED TV s become cheaper in larger sizes. LCD TV s have been seen at 100"+ and above but they are not common or as affordable.
So, is an LCD TV better than a Plasma TV?
The short answer is that it depends. Lets assume that we compare an LCD TV with an equally sized Plasma TV. Also, assume anything that applies to an LCD applies to an LED, unles specified otherwise. First we can compare the main qualities a TV shopper seeks before a purchase:
- Quality of colours
- Viewing angle
- Animation quality
- Price & Production Size
- Size and Weight, and
- Power Consumption
Category 1: Contrast
Firstly, it is good to point out what we mean by contrast ratio. Contrast ratio is the measurement of the difference in light intensity between the brightest white and the darkest black. The higher the contrast ratio the better the colour information will appear against a darker background. For example 1000:1 contrast ratio gives a better colour representation against a darker background then say 500:1 contrast ratio.
Modern plasma TV s boast contrast ratios in the order of tens of thousands to 1, Panasonic for example. Much technology goes into these plasma screens to block light from emitting from pixels which should be black. In comparison LCD displays must block the the white backlight to create blacks. In LCDs more energy is typically consumed to create black pixels. Any backlight passing through an LCD pixel causes black level degradation. This effects LCD contrast ratio. Contrast rations for most LCD TV s will be lower than most good plasma TV s.
Category 2: Brightness
Within a Plasma TV, each red green and blue cell of each pixel is lit on its own allowing for great brightness levels. Within an LCD TV, brightness is related to the intensity of the backlight. LCDs of late are typically as bright as Plasma TV s if not brighter, but unfortunately this compromises the contrast levels.
Conclusion: LCD TV but plasma not too far behind
Category 3: Longevity
Typically plasma TV s, like CRT TV s, lose their brightness over time. A Fujitsu white paper (somewhat outdated now) states that if you watch 6 hours of TV for 14 years you lose 50% of the brightness. For most people, this does not pose a problem. For an LCD TV the back-light is filtered by the liquid crystal substrate. This means there is nothing to burn out except the backlight. The backlight may be replaced! For a plasma, the light originates from the pixels which cannot be replaced when it begins to lose its brightness.
Plasma TV s may come with some faulty pixels out of the box. From then, additional pixel failure after installation is quite rare. For a plasma, no circuits, switches or gates are present with each individual pixel. The electronic operations take place outside of the panel itself on a video board. This means if there is failure these components may be replaced by a qualified service expert, but could be expensive. For LCDs dot electrodes situated on every sub-pixel red green and blue. These, by contrast, are prone to failure over the life span of the LCD TV. They cannot be individually replaced.
Lastly, burnin does not occur in LCD TV s, which you may consider as increasing the longevity of the TV.
LCD manufacturers claim over 80000 hours for LCD monitors/TV s. Plasma manufacturers claim about 60000 hours of half life. This
allows LCDs to be used quite readily in commercial environments. The back light of LED TVs are infact LED arrays. These last the longest of all.
Category 4: Colour Reproduction
Colour reproduction of a plasma TV is somewhat more accurate than that of an LCD display. Why? Colours (Red, Green and Blue) on a plasma TV are produced directly from the RGB sub pixels in an omnidirectional manner. This means you see the colours "from the source" with full brightness from anywhere in the room. LCD sub pixels create colour by filtering (or subtracting wavelengths from) a white backlight. Note: White light is a combination of all colours. Further to this, black levels are reduced, with colour and black level degradation at angles more than 25 degrees off axis. Blacks on a LCD TV are produced by blocking the white backlight. Any transmission of this light also reduces the 'blackness' of blacks, one reason for the lower contrast ratios seen in LCD TV s in comparison to Plasma TV s.
Category 5: Viewing Angle
Plasma TV have typically a free viewing angle. This is primarily because light is emanated directly from the sub pixels whereby in an LCD TV light is eminated from the backlight. The backlight is then polarized by the sub pixels to produce colour, in effect causing degradation at angles more than 25 degrees off axis. However with new substrate materials and improving technology LCD TV s can only get better.
Category 6: Animation Quality
Its very important for TV s to be able to display fast paced action movie scenes with no blury, smearing afterimages. For LCD TV s the switching speed within subpixels for for display content is quite slow, making blurring a common problem. With 200Hz+ refresh rates, this has issue has largely been eliminated. The switches need time to cycle through the on-off sequence, typically 1/30th second. This is more time than it takes to display two video fields - so rapidly moving LCD images leave trails behind them, or the images seems like its blurred.
While LCD technology has come a long way, there is still room to improve in this department.
Later model LCD TV s have a grey to grey response rate of below 8ms, but they still seem to offer an inferior animation to plasma. Plasmas have refresh rates of over 600Hhz.
Conclusion: Plasma, with LCD TV quickly catching up
Category 7: Burnin
LCD has no image burn-in problems to consider. The fluorescent backlight of LCD TV s or LED for LED TVs send light through its sub pixels which polarize and filter the light. Plasma displays do have burn-in problems. An issue which is problematic for plasma display technology. Burn-in is not so much of a problem when watching TV or movies because the images being displayed change often. However playing video games, displaying static information in displays or use as a computer monitor will cause burn-in for a plasma TV. In such situations, LCD is clearly the superior choice. Burn-in can be washed out somewhat by using gray images or a series of full colour images over many hours.
Category 8: Price and Prodiction Size
LCD TV s are difficult to produce in larger sizes while minimising pixel defects. This is seen by the fact that there are no displays greater than 60"/100" available at competitive prices. For now, the plasma TV is enjoying economies of scale for larger TVs and will remain cheaper for at least the next few years. However, expect LCD prices to near plasma TV prices and eventually become cheaper.
Conclusion: Plasma but LCDs are improving in this domain
Category 9: Size and Weight
If you thought TV s could not get thinner, think again. LCD TV s are thinner than plasma TV s and they are lighter! LCD TV s can be hooked up on a wall less worry about structural wall sturdiness than a Plasma TV. LEDs are even thinner again. LED back light arrays come in smaller sizes than fluorescent lamps.
Category 9: Power Consumption
Plasma TV s require thousands of sub pixels to be lit while LCD TV s use a fluorescent or LED backlighting technique. In summary LCD TV s typically use half the power (watts) of Plasma TV s. In some instances, plasma can use less power than an LCD. The LED backlight typically uses less power than fluorescent bulbs. We get in much more detail in our LCD and Plasma TV Buying Guide.
Written by Jim P. BE Comp MBiomed, Last updated 2010.
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