What's a plasma TV?

Question

What's the difference between a flat panel LCD tv and a plasma tv? And what's the difference between SD, ED, and HD?

Answer 1

plasmas are generally bigger than LCD flat panel, as well as utilizing a completely different technology.
SD = Standard Definition, the programming that we've been watching before HD showed up, horizontal scanning rate = 15.75KHz
HD = High Definition, this is the new super focused looking programming. right now is only available via cable or antenna (no DVD players yet), horizontal scanning rate = 33.5KHz
ED = Extended Definition, this is a type of display product that can display SD or HD, but the HD is not quite actual specs of HD. There is no signal associated with ED, it's just a very cheap knock off of HD.

Answer 2

There may be different scanning rates between SD, ED, HD, but that's not the most important difference. These three definitions mainly differ in resolution - the total number of pixels that fill the screen. The higher the resolution, the better the image quality.

SD (Standard Definition) - this is what we are used to from the pre-HD days. SD TV's have a resolution that is no better than 640 horizontal pixels by 480 vertical pixels (640x480)

ED (Enhanced Definition) - it's the in-between resolution - a little better than SD, but not nearly as good as HD. It's usually 720x480 or maybe a little higher. The other difference is SD is always interlaced (every other horizontal line is refreshed on the screen when a new frame is displayed) whereas ED is progressive scan (every consecutive line is refreshed) to give it a little better quality.

HD (High Definition) - this is the big dog & the future of television. In the US, two standards are used: 1080i & 720p. 1080i means that the resolution is 1920x1080 & interlaced, and 720 is 1280x720 and progressive. Most HDTVs display 720p, but more are being made to display 1080i. In fact, those HDTVs are actually 1080p. You don't have to buy a 1080p HDTV to support both resolutions. All 720p displays can down-convert 1080i to 720p. There is a HUGE difference between SD & HD in image quality. Once you go HD, you never want to go back.

The other cool thing is that all HD programming over the air or on cable also has Dolby Digital 5.1 surround sound.

Answer 3

HD = high definition
LCD = Liquid Crystal Definition

sorry that's all i know, and i do not recommend plasmas

Answer 4

For the past 75 years, the vast majority of televisions have been built around the same technology: the cathode ray tube (CRT). In a CRT television, a gun fires a beam of electrons (negatively-charged particles) inside a large glass tube. The electrons excite phosphor atoms along the wide end of the tube (the screen), which causes the phosphor atoms to light up. The television image is produced by lighting up different areas of the phosphor coating with different colors at different intensities

Cathode ray tubes produce crisp, vibrant images, but they do have a serious drawback: They are bulky. In order to increase the screen width in a CRT set, you also have to increase the length of the tube (to give the scanning electron gun room to reach all parts of the screen). Consequently, any big-screen CRT television is going to weigh a ton and take up a sizable chunk of a room.

Recently, a new alternative has popped up on store shelves: the plasma flat panel display. These televisions have wide screens, comparable to the largest CRT sets, but they are only about 6 inches (15 cm) thick. Based on the information in a video signal, the television lights up thousands of tiny dots (called pixels) with a high-energy beam of electrons. In most systems, there are three pixel colors -- red, green and blue -- which are evenly distributed on the screen. By combining these colors in different proportions, the television can produce the entire color spectrum.

The basic idea of a plasma display is to illuminate tiny colored fluorescent lights to form an image. Each pixel is made up of three fluorescent lights -- a red light, a green light and a blue light. Just like a CRT television, the plasma display varies the intensities of the different lights to produce a full range of colors.

The central element in a fluorescent light is a plasma, a gas made up of free-flowing ions (electrically charged atoms) and electrons (negatively charged particles). Under normal conditions, a gas is mainly made up of uncharged particles. That is, the individual gas atoms include equal numbers of protons (positively charged particles in the atom's nucleus) and electrons. The negatively charged electrons perfectly balance the positively charged protons, so the atom has a net charge of zero.

If you introduce many free electrons into the gas by establishing an electrical voltage across it, the situation changes very quickly. The free electrons collide with the atoms, knocking loose other electrons. With a missing electron, an atom loses its balance. It has a net positive charge, making it an ion.

In a plasma with an electrical current running through it, negatively charged particles are rushing toward the positively charged area of the plasma, and positively charged particles are rushing toward the negatively charged area.







In this mad rush, particles are constantly bumping into each other. These collisions excite the gas atoms in the plasma, causing them to release photons of energy

Xenon and neon atoms, the atoms used in plasma screens, release light photons when they are excited. Mostly, these atoms release ultraviolet light photons, which are invisible to the human eye. But ultraviolet photons can be used to excite visible light photons, as we'll see in the next section.

Inside the Display
The xenon and neon gas in a plasma television is contained in hundreds of thousands of tiny cells positioned between two plates of glass. Long electrodes are also sandwiched between the glass plates, on both sides of the cells. The address electrodes sit behind the cells, along the rear glass plate. The transparent display electrodes, which are surrounded by an insulating dielectric material and covered by a magnesium oxide protective layer, are mounted above the cell, along the front glass plate.




Both sets of electrodes extend across the entire screen. The display electrodes are arranged in horizontal rows along the screen and the address electrodes are arranged in vertical columns. As you can see in the diagram below, the vertical and horizontal electrodes form a basic grid.





To ionize the gas in a particular cell, the plasma display's computer charges the electrodes that intersect at that cell. It does this thousands of times in a small fraction of a second, charging each cell in turn.

When the intersecting electrodes are charged (with a voltage difference between them), an electric current flows through the gas in the cell. As we saw in the last section, the current creates a rapid flow of charged particles, which stimulates the gas atoms to release ultraviolet photons.

The released ultraviolet photons interact with phosphor material coated on the inside wall of the cell. Phosphors are substances that give off light when they are exposed to other light. When an ultraviolet photon hits a phosphor atom in the cell, one of the phosphor's electrons jumps to a higher energy level and the atom heats up. When the electron falls back to its normal level, it releases energy in the form of a visible light photon.




The phosphors in a plasma display give off colored light when they are excited. Every pixel is made up of three separate subpixel cells, each with different colored phosphors. One subpixel has a red light phosphor, one subpixel has a green light phosphor and one subpixel has a blue light phosphor. These colors blend together to create the overall color of the pixel.

By varying the pulses of current flowing through the different cells, the control system can increase or decrease the intensity of each subpixel color to create hundreds of different combinations of red, green and blue. In this way, the control system can produce colors across the entire spectrum.

The main advantage of plasma display technology is that you can produce a very wide screen using extremely thin materials. And because each pixel is lit individually, the image is very bright and looks good from almost every angle. The image quality isn't quite up to the standards of the best cathode ray tube sets, but it certainly meets most people's expectations.

The biggest drawback of this technology has to be the price. With prices starting at $2,000 and going all the way up past $20,000, these sets aren't exactly flying off the shelves. But as prices fall and technology advances, they may start to edge out the old CRT sets. In the near future, setting up a new TV might be as easy as hanging a picture!

Answer 5

just go to best buy and they will tell you.