NOTE: Although the information below can help to give you an understanding of the different display types, it is also important to look at these different types in-person. Also keep in mind that display performance can vary widely even within the same type – this is why it is extremely helpful to go to review sites such as http://reviews.cnet.com/ to find out which models are the best.
Cathode Ray Tubes (CRTs) are the traditional type of display that has been around since the dawn of television. They tend to have the deepest black levels and the best viewing angles. Black level refers to how well darker colors can be displayed, while viewing angle refers to how good the picture is when viewed off to the side. The main downsides to CRTs are that companies have largely stopped making them, they are very large and heavy, and there is a chance of burn-in. Burn-in, also known as image retention or image persistence, is “when an image--such as a stock ticker, a network logo, or letterbox bars--gets etched permanently onto the screen because it sits in one place too long” . CRTs exist in both direct-view and projection form, with both forms having the same flaws. Direct-view is another way of saying non-projection.
Plasma Display Panels (PDPs) are flat-panel displays that, like CRTs, have very good black levels and viewing angles. Unfortunately, like CRTs, they also have a risk of burn-in, although this burn-in may be only temporary . Plasmas also are generally not sold in sizes below 42 inches . With the exit of Panasonic from the plasma market, LG Electronics and Samsung are the only two companies left that will be making plasmas .
Liquid Crystal Displays (LCDs) tend to have a somewhat worse black level and viewing angle than CRTs and plasmas. Although temporary and/or permanent burn-in may also occur on LCDs  , it is overall quite unlikely, particularly compared to CRTs or plasmas . LCD technology is used for both flat-panel and projection displays.
Light-Emitting Diode (LED) technology can be used in flat-panel LCDs as well as LCD and Digital Light Processing (DLP) projectors. When used in flat-panel LCDs, such displays are usually referred to simply as LED displays. LCDs with LED technology can provide a deeper black level but also tend to cost more . When used in projectors, the major benefit is that there is no lamp to worry about replacing      .
Front-projection is the technical name for a projector. A projector, as you probably know, shines light onto a wall or screen to display an image. Depending on the projector used, how far away the projector is from the wall, and how much the image is enlarged, a projector can offer a max image size anywhere from 100 to 600 inches, with 300 being fairly typical. With 1080p projectors starting at under $1,000 , projectors can be a relatively affordable large-screen alternative to other types of displays. Also, using a projector in conjunction with an acoustically transparent screen allows you to place the center speaker in a surround sound system behind, rather than above or below, the screen . The major downside to a projector is that if a room is too bright, the image from a projector can be hard to see. Solutions to this problem include making the room darker, getting a bright projector , getting a high-gain screen , or reducing the size of the image .
Rear-projection TVs (RPTVs) are similar in appearance to flat-panel displays, but thicker. This additional thickness is designed to make room for a built-in projector behind the screen, hence the name rear-projection. This type of display is no longer manufactured .
Organic LED (OLED) displays offer an excellent picture but, like CRTs and plasmas, can potentially exhibit burn-in. Current OLED High-Definition TVs (HDTVS) in particular have some issues to be worked out such as having a high price, only coming in a curved shape, only coming in a 55-inch size, and not having 4K resolution .
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