What is the Difference Between a Plasma, LCD, LED and DLP?

Help!  What is the Difference Between a Plasma, LCD, LED and DLP?

There are not many hobbies that have more three letter acronyms than Home Entertainment.  We can create them by the dozens at a drop of the hat.

One of the more vexing topics deals with video, what we called televisions in the old parlance, Hi Definition, 1080p and the rest.

Let’s sort this out for you.

First, the issue of resolution which is measured by the number of pixels or “dots” if you will, that the set is capable of displaying for any image.  Today, most televisions or projectors are capable of 720 or 1080.  So what does that mean?  From Wikipedia we have the following:  “1080p is the shorthand identification for a set of HDTV video modes that are characterised by 1,080 lines of vertical resolution (1,080 horizontal scan lines)[1] and progressive scan (meaning the image is not interlaced, unlike the 1080i display standard).

1080p, sometimes referred to in marketing materials as "Full HD", typically refers to the capability to accept 1080p signal and display it with native resolution of at least 1080 lines, as well as the capability to upscale lower-resolution material to 1080p.”

The same basic definition applies to the 720p label, only with less horizontal scan lines.

All you really need to know is that 1080p is the highest resolution currently available.  So this is the best right?

Not necessarily.  For many applications, in particular televisions with a size of about 42 inches diagonal, you really do not need anything more than 720p since the human eye is unable to distinguish anything higher than this resolution in such a small display.

So with that out of the way, what about the Plasma, LCD, LED, DLP?

These terms refer to the type of technology used to display the picture.

Let’s start with DLP.  Invented and licensed by Texas Instruments, DLP is usually found in larger “rear display” televisions 50 inches or larger.  They are not “flat” per say but have slimmed considerably since their introduction years ago, and now are typically about 16 to 20 inches deep.  The stand on furniture, tv stands or the floor.

Picture quality is superb.  They use 6 colors to build the image, whereas the others use only three.  The speed of the refresh, or how often the image is rebuilt, is very fast, so sporting events and high speed scenes are displayed accurately and without the “blur” seen in other technologies.

The downside if any, is the fact that these sets use lamps and a color wheel.  The lamps last anywhere from 3000 to 5000 hours and the color wheels have been know to fail, but this is very uncommon, due to the use of air bearings in the mechanism.  The best part is that they are inexpensive in terms of “inches of display” per dollar.  Mitsubishi is the King of DLP’s.

Plasmas are next.  The first of the flat screen televisions, Plasmas have a colored reputation, no pun intended.  Early plasmas were subject to burn in of images left displayed for too long, failed pixels resulting in black dots in the panels, and a shorter life span than other technologies.  That as they say, is all history.

Today’s Plasma televisions offer much to the consumer.  First, they have a native processor or refresh speed of 600mhz, which is two or three times the typical LCD or LED.  That means high speed images display crisply and with no blur.  Great for sports or action films.

Next, plasmas recreate black levels superbly.  Black is important as it provides the foundation for the other colors in the spectrum.  This is possible because each plasma pixel is an independent managed cell.  Each pixel cell is in essence a microscopic florescent bulb capable of displaying colors or black. The native state for this pixel is black when off, so displaying black levels means the tv just turns off the needed pixels as required.

Colors accuracy and saturation are superior to LED and LCD and about the same as DLP.

Contrast ratios measure the difference between the whitest white and blackest black a set can reproduce.  Here Plasmas are also slightly better compared to LED and LCD’s. 

Viewing angles, or how far off center you can view acceptably, are much better in Plasmas than the other technologies.

Of interest is the fact that THX Studios will only use DLP’s and Plasmas for calibrating and determining THX certification for Hollywood’s film productions.

LCD’s are actually using the oldest technology of the group.

An LCD pixel is also an individually managed cell.  They use electric charges to twist and untwist liquid crystals contained in each cell, which causes them to block light and emit black.  This means at rest an LCD cell is white while at full power they will create black.  As a result they do not do as good a job as Plasmas at emitting black.

LCD’s produce color by manipulating light waves and subtracting colors from white light.

What makes all these liquid crystals display is a “backlight”, which is usually a florescent tube behind the LCD display which shines light through the LCDs presenting an image to the viewer.

LCD’s two biggest advantages are their ability to produce a very bright picture, which is needed in many room situations, and do it with less energy, making it somewhat more energy efficient.

Overall picture quality is always a matter of personal choice, but other than brightness, LCD’s typically come in second place to Plasmas or DLP’s.

And now we have the new kid on the block, LED televisions.

So what is an LED?  Surprise!  It’s actually an LCD.  The trick is that in an effort to produce better levels of black, the florescent tube has been replaced by a series of LED lights, grouped behind the LCD panel in “zones” or along the edge of the display “edge lit”.  This allows the tv to selectively turn on and off individual LEDs when the set needs to display a black image on a scene or part of a scene.

The result is very successful, in that LEDs do a much better job of displaying black levels, almost equal to Plasmas and DLP’s.

LED televisions are dramatically thin and light, due to the replacement of the florescent backlite.

Finally, based on dollar cost per viewing inch, as of December 2010, Plasmas offer about a 30% price advantage to LCD’s and LCDs.