For the past 75 years , the Brobdingnagian majority of boob tube have been built around the same technology : thecathode ray tube(CRT ) . In a CRT boob tube , a gun fire a beam ofelectrons(negatively - charged subatomic particle ) inside a tumid glass tube . The negatron excitephosphor atomsalong the broad ending of the tube ( the screen ) , which causes the phosphor atoms to light up . The television image is produced by lighting up dissimilar areas of the phosphor coating with unlike color at unlike loudness ( seeHow Televisions Workfor a elaborate explanation ) .
Cathode ray tubes acquire crisp , vibrant picture , but they do have a serious drawback : They arebulky . for increase thescreen widthin a CRT readiness , you also have to increase thelengthof the tube ( to give the scanning electron gun way to reach all parts of the covert ) . Consequently , any big - screen CRT telecasting is break down to press a ton and take up a sizable chunk of a way .
A new choice has bug out up on store shelves : theplasma mat control panel display . These tv have wide screens , comparable to the big CRT sets , but they are only about 6 inches ( 15 cm ) thick . In this clause , we ’ll see how these exercise set do so much in such a diminished blank space .
If you ’ve readHow Television Works , then you understand the basic idea of a standard television or monitor . Based on the information in a video signal , the television lights up M of flyspeck pane ( calledpixels ) with a mellow - energy beam of electrons . In most systems , there are three pixel color – red , green and blue – which are evenly distributed on the silver screen . By fuse these colors in different proportion , the telecasting can bring forth the entire color spectrum .
The basic theme of a plasma display is to illuminate diminutive , coloredfluorescent lightsto take form an image . Each pixel is made up of three fluorescent lights – a red igniter , a dark-green light and a blasphemous light . Just like a CRT television , the plasma showing varies the intensities of the different lights to produce a full range of colors . On the next page , learn how the plasma works .
What Is Plasma?
The central element in a fluorescent light is aplasma , a accelerator pedal made up of free - flowingions(electrically charge atoms ) andelectrons(negatively charged particles ) . Under normal conditions , a throttle is mainly made up of uncharged particles . That is , the individual gas atoms include equal number of protons ( positively charge atom in the atom ’s nucleus ) and electrons . The negatively charged electrons perfectly balance the positively charged proton , so the atom has a nett cathexis of zero .
If you premise many complimentary negatron into the gas by build an electric voltage across it , the billet changes very speedily . The innocent electrons collide with the atoms , pink loose other electron . With a missing electron , an atom loses its equaliser . It has a net overconfident complaint , make it an ion .
In a plasma with an electrical electric current running through it , negatively charged corpuscle are rushing toward the positively saddle area of the plasm , and positively charged corpuscle are race toward the negatively charged domain .
In this sore flush , molecule are constantly bumping into each other . These collisions excite the accelerator atoms in the blood plasma , causing them to releasephotonsof energy . ( For details on this process , seeHow Fluorescent Lamps Work . )
Xenon and Ne particle , the atoms used in plasma screens , releaselight photonswhen they are emotional . Mostly , these atoms releaseultravioletlight photons , which are unseeable to the human optic . But ultraviolet photon can be used to excite visible clear photon , as we ’ll see in the next section .
Inside a Plasma Display
The xenon and Ne gas in a plasm television is contain in hundreds of thousands of tinycellspositioned between two plate of glass . farsighted electrode are also sandwiched between the field glass plates , on both side of the cells . Theaddress electrodessit behind the cells , along the rear glass home . The transparentdisplay electrodes , which are surrounded by an insulatingdielectric materialand underwrite by amagnesium oxide protective layer , are mounted above the cell , along the front chalk plate .
Both sets of electrode continue across the entire projection screen . The display electrodes are coiffure in horizontal rows along the screen and the address electrode are do in erect columns . As you could see in the diagram below , the vertical and horizontal electrodes form a basicgrid .
To ionize the gas in a particular cell , the plasma display’scomputercharges the electrode that intersect at that cellular phone . It does this K of times in a little fraction of a 2nd , charging each cell in turn .
When the intersecting electrodes are charged ( with avoltagedifference between them ) , an electric current current through the flatulency in the cellphone . As we saw in the last section , the stream produce a speedy flowing of charge particles , which stimulates the gas atoms to release ultraviolet photon .
The expel ultraviolet photons interact withphosphor materialcoated on the inside wall of the cell . Phosphorsare substances that give off light when they are discover to other brightness . When an ultraviolet photon hits a phosphor atom in the cell , one of the phosphor ’s electrons spring to a mellow energy level and the molecule stir up up . When the electron fall down back to its normal level , it releases Department of Energy in the form of avisible light photon .
The phosphors in a plasma display give off colored sparkle when they are excited . Everypixelis made up of three separatesubpixelcells , each with dissimilar colored phosphor . One subpixel has a red light phosphor , one subpixel has a green light phosphor and one subpixel has a blue twinkle phosphor . These gloss immingle together to make the overall color of the picture element .
By varying the pulses of current flow through the dissimilar cells , the control organisation can increase or lessen the intensity of each subpixel color to make one C of different combinations of cherry , green and down . In this means , the command system can produce colors across the full spectrum .
The independent advantage of plasma show technology is that you may acquire a very wide screen using extremely flimsy material . And because each pixel is light individually , the image is very bright and looks serious from almost every slant . The image quality is n’t quite up to the standards of the best cathode beam subway system sets , but it certainly meets most hoi polloi ’s expectations .
The biggest drawback of this technology has been theprice . However , falling Price and advances in engineering mean that the plasm display may soon edge out the old CRT sets .
To learn more about plasma display , as well as other television system technologies , break out the links that keep up .
