Our Design Engineer, Jay McCutcheon, researches and writes about topics of interest in the A\V world. Send him ideas and we’ll post his responses here!

With today’s broadening technology, it can be very confusing which display type to choose. I have used all three types of displays (LED, LCD and Plasma) in designs and there are a few things that set each type apart.

First let’s define each type. An LCD-TV has liquid crystal between the display panels of the TV, which gets activated when power is applied to it. Additionally, the LCD-TV uses a compact florescent lamp (CFL) for back lighting.

The LED-TV works similar to a LCD-TV but it uses light emitting diodes (LED) that are used to back light the TV.

The Plasma, on the other hand, is a whole other animal. A plasma TV has a sheet or layer of individual plasma cells, which get activated when electricity is passed through them.

So we have defined the three types. You may notice I have not mentioned Rear Projection TVs. Why? It is not typically used in a commercial environment and South Central A\V does not spec Rear Projection TVs.

Criteria 1: Contrast Ratio

The contrast ratio is the TV’s ability to show high contrast areas on the screen. They are typically the areas that show black and white in the picture.

Plasma TVs generally have better contrast ratios than LCD or LED and that is due to the individual plasma cells, which automatically turn themselves off on the darker parts of the screen.

The LCD, which uses the florescent lamps, only dims the areas and does not provide the same contrast. The LED does not have plasma either, but the LEDs actually twist slightly to reduce the light — thus giving a stronger contrast than an LCD.

Criteria 2: Viewing Angle

This is the angle on which the TV’s image can be viewed. All TVs can show a great picture when they are viewed head-on, but not everyone gets to enjoy this ideal viewing angle.

Again, like with contrast, the Plasma wins. It produces a good image at virtually any angle. The LCD falls back again because you lose a lot of color and detail when viewing the screen from the sides.

Criteria 3: Color

Good, bright color helps the viewer to clearly understand the image being displayed. All three types of TVs do a good job of color transmission.

Criteria 4: Motion

LCD manufacturers have been fighting this problem for a while. The hertz count is the key. Low hertz rates cause motion lag so the higher the hertz the less the lag. 60Hz used to be the norm but 120Hz has taken its place.

Some manufacturers boast of 680Hz refresh rate and that is completely unnecessary. The human eye cannot even try to keep up with that. So anything from 60Hz-480Hz is just fine.

Criteria 5: Power

Until the release of the LCD, the plasma won this area. Since every pixel on a plasma needs to be lit, the power drain was huge.

But with an LCD the single CFL does not require the same power needs.

The LED is now the clear winner. Since the LED does not need that much power it is now the most energy efficient display available.

Criteria 6: Life

This is where Plasma manufacturers have been failing. The quality and brightness of a plasma really takes a beating in what seems like a very short time.

Although the Pioneer I have is a 2005 model, which still looks great, it does have a small problem. I inadvertently left it on ESPN for a weekend and returned home to find the next issue plasmas have: Burn in.

Lucky for me it is only in the lower right hand corner (where the ESPN logo resides) and has faded over the years but it is still there and is a constant reminder of my forgetfulness. With that said, LCD and LED do get Burn in but it is not as common and is very rarely seen.

The LCD wins the lifespan criteria while we can only judge the Plasma and LCD since the LED is fairly new. But news in the plasma field states that makers are working to lengthen their lives.

Criteria 7: Price

In the commercial world the prices of plasmas, LCDs and LEDs change rapidly. In many designs the price is the most important criteria versus the other six we have discussed.

The plasma has had a much lower price than the LCD but since more screen sizes are easily produced for the LCD market the price for LCDs will start to fall even faster and that difference between the Plasma and LCD will shrink.

LED TVs are the costliest of the three types we have looked at. This is probably due to the fact that the LED TV is a new technology and the production rate has not met the rate that the LCD and Plasma manufacturers have set.

In the commercial world the prices of plasmas, LCDs and LEDs change rapidly. In many designs the price is the most important criteria versus the other six we have discussed.

The plasma has had a much lower price than the LCD but since more screen sizes are easily produced for the LCD market the price for LCDs will start to fall even faster and that difference between the Plasma and LCD will shrink.

LED TVs are the costliest of the three types we have looked at. This is probably due to the fact that the LED TV is a new technology and the production rate has not met the rate that the LCD and Plasma manufacturers have set.

Conclusion: Personal preference.

Price seems to dictate the overall choosing of displays and in a commercial setting lots of people are going to view the display you choose and not everyone will see it the same way. Plus, keep in mind what you are going to display.

If it is plain cable, then the LCD may be the way to go. But if you are going to be showing movies and cable, then the plasma or LED might be the correct fit.

Jay McCutcheon, CTS can be reached at 615.369.6013 jmccutcheon@southcentralav.com

Thanks to Wikipedia, Buzzle.com, LG and Samsung for research help.