Gadgetory

they all look about the same from a distance don't think all those flat panel TVs but how they generate the image is the majority of what you're paying for SIA may as well understand what's in there let's break it down and understand the types of TV displays okay first off LCD or liquid crystal display has long been the volume leader probably what you have in most or your only TV right now LCD TVs are known for a good - very good picture a wide range of sizes and prices from low-cost portables to big dollar 55 inch TVs and they don't suffer from burn-in but they do dim and tend to color shift as they age now you may have guessed by now these LCD TVs are actually the same technology as your flat panel computer monitor or the display on your laptop let's take a look inside this themed panel you actually look at is actually a sheet of transistors that open and close like little shutters to allow light through and in the process they go through red green and blue lenses also embedded in this piece of glass that light I'm talking about comes from this fluorescent panel behind it and that creates two problems first of all this whole light panel in a traditional LCD is always on so when this picture wants to show some area of black all it can do is close the transistors in that area and hope no light leaks through but it always does so at best you get deep gray that's what we talk about we measure black level on a TV and black level is key to everything else looking really good and these TVs struggle with it secondly this light source back here is pretty bulky and that makes for a thicker TV overall enter the LED LCD for illumination they use a strip of LEDs kind of like these right here and mount them behind or around the picture that means a thin case design front to back because the LED lights are so low profile you also get very even brightness and color throughout the TV because LEDs don't age oddly like fluorescent panels and LEDs tend to use less energy than other TV types okay here's where it gets a little bit complicated there are two kinds of LED LCD TVs edgelet and local dimming edgelet LED LCDs have their LEDs mounted around the edges of the TV as you might have guessed they can be particularly thin because the LED lighting is pushed out to the edges they may have some issues though with evenness of illumination at this point in their development the local dimming type has a complete grid of LEDs behind the picture screen these tend not to be the very thinnest but they're quite shallow and they could really go a long way toward offering that holy grail of LCD TVs and that is showing deep black levels because in this case when the TV needs to show black it just shuts off the LED light in that part of the picture finally there's plasma now unlike the LCD TVs we've been talking about there is no separate light source in the back behind the picture instead every pixel that you see is a little tube of glowing gas or plasma that emanates light on its own unlike LCD the picture is bright and accurate from just about any viewing angle and when a plasma TV is really good it still tends to be the best looking TV technology out there now these guys are not as energy-efficient or cool running as led LCDs can be and surprising to a lot of folks plasmas are actually the best value in larger sizes like 42 inch and above if you shop aggressively ok now 3d don't worry about it all these types of TV displays can show 3d if the rest of the television is 3d compatible the display type doesn't determine that so I know there's a lot here to digest but it's important to know what you're buying when something is this expensive and this much of a pain that take back to the store now what really matters is which of the TVs should you get using any of these technologies and for that you should head over to CNET's TV reviews section where our TV guru David Katz Myer keeps us on top of the best models regardless of display tech