Television Picture

[kenel]

A friend of mine and I had a conversation the other day about the new Plasma Televisions, and why they were so much better than conventional ones. Needless to say, I had no clue why. What is used inside of "older" televisions to produce pictures, and why is the Plasma TV so much better?

[fafalone]

Older TVs use an electron gun to energize phosphorus and other compounds to produce colors. I'm not sure how plasma displays work, never looked at it... but I know they don't require as much size (thinner) and have a significantly higher resolution.

[PlanetCpp]

plasma displays are basically fluorescent lights arranged in a matrix. The thin plate of glass houses thousands of little spaces that if looked at closely would look like this: \_/ . inside there is gas and i believe there is just a colored layer (red green blue), i know certain gases can be combined to glow certain colors but im sure its only a layer of film. each pixel as you see it is actually 3 chambers of gas 1 red, 1 green, and 1 blue. this matrix of chambers is hooked up to electrodes and is set up so that the electrodes can be charged like a grid, so that only one chamber can be charged a certain intensity at a time. when all 3 are charged you get your pixel, the gases light up, more charge = brighter light since more photons. the sides of the chamber are reflective and like a car lamp, sort of, they beam the light out at you. thats basically it. i dont know of the ups and downs to this, fluorescent light is annoying to most people but im sure in the tv its fine.

[aman]

Also a TV screens phosphorus coating is only hit by a small beam running top to bottom horizontaly sixty times a second to refresh the glow so at any one point in time only one pixel is being illuminated. On a plasma screen the whole screen is illuminated constantly through each 1/60 of a second cycle.

Just aman

[nameta9]

They are actually worse. This is another case where "progress" is false and we actually loose functionality, quality or both because the industry exploits the fact that people are stupid. CRT monitors have reached a very high level of perfection (study DOT PITCH for example), the monitor I am writing with is 5 years old and has a quality and image that is light years ahead of any plasma, or lcd display and it would even cost less than a 100 dollars. But the industry can't make much money on them anymore so they are shoving down everyones thoat all the CRAPPY flat screens that have horrible quality from all the technical points of view. Another example of we going backwards instead of forwards, like the fact that tone controls are getting rarer to find on stereos.

[RICHARDBATTY]

They are actually worse. This is another case where "progress" is false and we actually loose functionality, quality or both because the industry exploits the fact that people are stupid. CRT monitors have reached a very high level of perfection (study DOT PITCH for example), the monitor I am writing with is 5 years old and has a quality and image that is light years ahead of any plasma, or lcd display and it would even cost less than a 100 dollars. But the industry can't make much money on them anymore so they are shoving down everyones thoat all the CRAPPY flat screens that have horrible quality from all the technical points of view. Another example of we going backwards instead of forwards, like the fact that tone controls are getting rarer to find on stereos.

I agree that the insentive for producing these new types of vd are market driven but, the dpi bit is mainly a problem with the broadcast resolution. I have an lcd tv which has double the vertical lines and thirty percent more horizontal lines. This is only any use when viewing images that supply the extra lines but interpolation improves on even normal broadcasts. Also remember that moniters for computers are usualy viewed close up and tvs from a distance. I think plasma is a bad idea from a power consumption and reliability / repairability point of view though.

[Goalfinder]

Just a comparitive analysis

Plasmas perform extraordinarily well under most ambient light conditions. Very bright light does not wash out the image on the screen. The beauty of these flat screens is that, unlike front view projection screens, you don't have to turn off the lights to see the image clearly and easily. Therefore, plasmas are excellent for video conferencing and other presentation needs, which require the lights to remain on.

 

Another characteristic of a plasma panel is the extreme viewing angles both vertically and horizontally. With 160 degrees viewing angle, people sitting off to the side of the plasma screen will still be able to see the image without losing any of it.

 

Plasmas tend to be very lightweight in comparison to similar sized standard display monitors and television screens.

 

No existing display system can compete with the low depths available in plasma panels. The thinness of theses systems allows for the monitors to be placed virtually anywhere. Some plasma panels are known to be as thin as 3.5 inches deep.

 

They can be hung on walls, mounted to ceilings, flush wall mounted or placed on a tabletop. Many mount manufacturers are designing more creative ways to mount plasma panels because of the ease of engineering involved.

 

I hope that clarifies

[syntax252]

speaking of television, why is it that every time I see a television playing on a TV show or porgram, the television that is on television has a picture that is flopping?

[Pangloss]

That's usually due to a mismatch in refresh rates. NTSC video is about 60 fields per second, and monitors generally refresh at 75+. It's like watching the spinning propeller of an airplane through a spinning ventilation fan.

 

BTW, DLP is an interesting alternative technology to plasma. It doesn't look quite as good at the high end, but it's only a fraction of the price. As Goalfinder points out, nothing can compete with plasma, but DLP comes closer than most casual viewers can detect with normal programming (DVD, standard TV, and maybe even HDTV).

 

FWIW, I'm a huge home theater buff. I have an Infocus 4805 DLP-based projector, blasting the wall at 100+ inches with a very high quality image. Sound from a Yamaha and Klipsch arrangement that I'm pretty happy with. I've sunk thousands into it, and if you come over to my house and watch Lord of the Rings you'll think you're in the theater. It's not *quite* what plasma can do. But I've got a six-foot image on the wall that looks as good as plasma to 99% of viewers, vs a 42" plasma screen that would have cost as much as all my components combined. (grin)

[Lance]

I've sunk thousands into it, and if you come over to my house and watch Lord of the Rings you'll think you're in the theater.

 

Is that an invitation?

[Pangloss]

Ah, but that's the great thing about Home Theater -- you can build your own!

[badchad]

Well someone commented on how plasma wasn't as good of quality as a conventional CRT. However, plasma screen sizes are (obviously) much larger than can be achieved with a CRT.

[The Rebel]

I've heard that the life span of plasma screens are pretty small compared to CRT. That you may have to fork out to get it recharged / repurged. Anyone heard this?

[JohnB]

I have an Infocus 4805 DLP-based projector, blasting the wall at 100+ inches with a very high quality image.

Pangloss, do you use a white screen, or one of the new silver ones? I've seen the silver ones give a tremendous picture under (almost normal) ambient light conditions.

[Pangloss]

Actually at the moment I'm just using the freebie 76" screen that came with it, which I just raise into its shell when I want a larger image. The wall behind it is (conveniently) painted a matte white color, so it works out pretty well.

 

I'm eyeing a Carada Criterion 1.85 at 96" or 104" in Brilliant White. The tough part is getting the wife to agree to the $750+ price tag.