Is there plasma in a plasma TV? Yes. There is.
The bigger question is what exactly plasma is, and how it helps you to watch Strictly
Come X-Factor Out Of Here in glorious high-definition. Well the technology behind the television
barely evolved for the first 60 years of its existence. It relied on the cathode ray tube,
basically a device that could fire out a stream of electrons onto the back of a fluorescent
screen. The parts of the screen being hit by electrons would then glow, and the beam
of electrons would then run across the screen, in a series of parallel lines, multiple times
each second. This happens so quickly that our eyes, looking at the other side of the
screen, see a steady image. Early televisions had only one of these electron guns, meaning
their images were in what was called black and white (actually green and grey for anyone
old enough to remember.) But then colour television was invented -- giving
a new 'best thing since' to replace sliced bread -- by using three separate streams of
electrons to create red, blue and yellow which could then be combined to enable people to
finally make sense of televised snooker. But as our appetite for bigger TVs and sharper
images developed, so the humble Cathode Ray Tube screen started to hit problems. Televisions
were already heavy, electricity-hungry things, but as the size of screens increased they
had to become deeper as well -- so that the CRT tube could reach each corner of a screen.
The number of pixels that a CRT could support was also limited by the need for it to 'scan'
solution. The concept for the plasma display had been
invented as long ago as the 1930s, with a single-colour plasma displays being produced
in the 1960s and 1970s, especially for early computers. The principal is very simple: instead
of using a beam of electrons to create lines, the plasma screen uses what are in effect
tiny, quick-acting fluorescent light cells to form a picture. In a modern colour plasma
display, each pixel has three of these florescent lights, one in each primary colour, and fires
them intelligently to create the desired colour in the picture. LCD televisions, the sworn
enemy of Plasma systems according to the bloke in the telly use individual LCD 'shutters'
for each pixel to create a similar effect. But what is plasma? A plasma is basically
just an electrically conductive gas that contains both free-flowing ions (positively charged
atoms) and electrons (which are negatively charged.) If you introduce more electrons
by putting a voltage through this gas then these will begin to collide with atoms, knocking
off other electrons and turning them into ions. Then negatively charged particles will
start to move towards the positively charged area and vice-versa.
This causes the atomic equivalent of a motorway pile up, with particles smashing into each
other and -- with the xenon and neon gases used in plasma screens, - releasing photons.
Or light, as we call it. Most of this light is ultraviolet, which is invisible. But by
coating those tiny cells with phosphoric material, this can be changed into visible light when
it hits the side of the cells. Which it does a lot: a modern high-definition display -- with
1920 pixels across and 1080 up -- has over two million individual pixels, each being
fired dozens of times a second to produce different colours.
The result is that plasma displays are far more shallow than old CRTs -- you can stick
them on your wall -- but also that they can be scaled up by simply adding more pixels
and enough computing firepower to run them. Plasma TVs have been produced in sizes up
to 152-inches (the diagonal measurement across the screen) -- large enough for even the most
discerning rap star to watch himself waxing misogynistic in glorious high definition.
And now settle down to the Blu-Ray release of Ghost Busters and remind yourself how important
it is to never, ever cross the streams. Now if you haven't already what my mother
called square eyed through watching all this stuff about television why not go over to
Number Hub and find out just how many pixels can be squeezed into the world's largest TV.
Do that by clicking here...