New TV technologies bring a new vocabulary.
Here's a rundown of the latest that are available at ListenUp
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CRT (Cathode Ray Tube)
The venerable Cathode Ray Tube (CRT) has been around a long time -- since the earliest days of television. Basically, a CRT is a special vacuum tube that's covered with phosphors on the inside of the front side. An electron gun at the back of the CRT shoots electrons at the phosphors causing them to glow and, ultimately, create a picture. "Direct-view" televisions -- the type most of us have been watching for the last 50 or more years -- use a single multi-color CRT to create the image. For many years, front- and rear-projection TVs combined the images from a trio of mono-color CRTs (one red, one green and one blue) to produce a full-color picture. High-performance, CRT-based televisions are still considered by many to have the best overall image -- but many of the newer TV technologies are improving so rapidly that the performance advantage of the best CRTs won't exist for long. |
 Sony KV-34HS420 is a wide-screen CRT-based HDTV. |
 JVC HD-ILA sets are available in 52- and 61-inch screen sizes. |
D-ILA (Direct-Drive Image Light Amplifier)
JVC developed this special variation of micro-display technology. D-ILA devices use Liquid Crystal Display (LCD) technology to control light that is reflected onto a screen. Because D-ILA is a reflective technology, it is typically capable of delivering more light to the screen than transmissive LCD technology. In addition, the tiny electronics and switches used to control the action of the individual LCD "pixels" in a D-ILA device are mounted behind the liquid crystal layer (instead of between the pixels as is the case with traditional LCD devices), a technique that many viewers feel provides a much more seamless picture (similar in concept to Sony's SXRD). |
| DLP (Digital Light Processing) |
| One of several micro-display technologies, DLP is a "reflective" technology developed by Texas Instruments. At the heart of each DLP system is a small Digital Micro-mirror Device (DMD) that uses millions of extremely tiny mirrors to reflect light from a lamp (think of it as a highly specialized light bulb) to a screen. Each of those miniature mirrors represents a "pixel" in the image. The best DLP-based projection TVs (both rear-and front-projection) combine the output from three separate DMDs -- one for red, one for green and one for blue -- much like high-end CRT projectors. More affordable DLP-based projectors use a single DMD that then passes the light through a spinning color wheel to create the millions of colors you see on the screen. |
 The Samsung HLP5085 uses DLP technology. |
Flat-panel TV
Most of us use this term to refer to any ultra-slim, lightweight television that does not use a CRT. At this point, the two most common technologies for flat-panel TVs are plasma and LCD. |
 The Runco CL-710 uses DLP technology to display its high-definition image. |
Front-projection TV |
| A front-projection TV, also known as a two-piece television, includes a relatively small projector that produces an image that is reflected back on the screen. Front-projection TV systems can potentially display an image that fills up an entire wall without requiring the bulky cabinet that a rear-projection TV would need. However, for best viewing, the ambient lighting in the room must be strictly controlled. Front projectors using some of the new micro-display technologies can be very small and inconspicuous, which has led to a much greater acceptance among home theater owners. |
| LCD (Liquid Crystal Display) |
| LCD technology uses two polarizing transparent panels with a special liquid crystal solution trapped in between. When an electric current is passed through the solution, the crystals align in a pattern that blocks light. Flat-panel LCD TVs use a diffuse light source behind a large LCD panel. In projection TVs, much smaller LCD panels are used to block or pass light from a very bright lamp. In either case, since the light actually passes through the LCD layer, this method is referred to as "transmissive." |
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| Micro-Display |
| Micro-display is a generic term used for a number of the new projection TV display technologies. In general, a micro-display device uses a bight light source (the "lamp") to produce light that is either reflected (as with DLP), or passed through (as with LCD) the micro-display. The micro-display itself is often less than one inch in diagonal. |
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Plasma |
| Gas-plasma displays consist of two transparent glass panels with millions of tiny gas bubbles, or cells (one red, one green and one blue bubble for each pixel in an image), trapped in between. Electric currents applied to the cells cause the trapped gas to ionize and emit ultraviolet rays, which in turn cause the phosphors on the front side of each cell to glow, creating an image. Plasma TVs offer the benefits of high brightness and wide-viewing angles -- and, of course, you can hang them on the wall. |
Rear-projection TV |
| A typical rear-projection TV uses a mirror to reflect an image from some sort of display device. In the past, rear-projection TVs used the combined light output from three CRTs to project an image. Today, many of the newer rear-projection TVs -- especially the ultra-slim style sets -- use DLP or LCD micro-display device technologies. |
SXRD |
| SXRD is Sony's name for proprietary refinements to a reflective micro-display technology that uses a layer of liquid crystals to control the reflection of light to a screen. Because the electronics used to control the pixels that make up the liquid crystal layer are located beneath -- rather than within -- the layer, more pixels can be densely packed on the device resulting in a smoother image on the screen. (Pixel elements are separated on an SXRD device by less than a width of a human hair.) Sony also claims much faster than average pixel response time, meaning images with motion will look just as sharp as still pictures (similar in concept to JVC's D-ILA). |
