How LCD Screens Work.

This explanation requires a few sub explanations so please bare with me. I promise it will all make sense in the end.

What Is A Liquid Crystal and What Can It Do
A liquid crystal is a substance with unusual properties. That is it behaves differently to most substances and this is quite useful. If you supply an electrical current to one of these liquid crystals then it temporarily changes its 'state' and can be controlled to either allow light through it or not.

Liquid Crystals and Colour
Now imagine a light and then a liquid crystal and then a colour filter. If the light is on and you can control if the liquid crystal allows it through then you can control the switching on and off of a coloured light.

Sub Pixels
Now if you can accept that mixing combinations of Red, Green and Blue lights at different intensities can make any colour (or one of about 16 million) then we are getting somewhere towards understanding how LCD TVs work. Each individual Red, Green or Blue light is switched on and off at varying intensities by varying the electrical current passed to it. Each of these lights is called a Sub Pixel.

Pixels
A pixel is made of 3 sub pixels (phosphors), It is the dot you can actually see if you put your face really close to the screen. Combinations of dots (pixels) make a picture, Refreshed (redrawn) quickly (50 times a second) makes the moving picture that we see.

Summary So Far:-
Fine so all this is great but how does an LCD TV know where and how to light these millions of sub pixels at millions of different combinations and intensities to light about a million(depending on the specific TV) pixels, that form a picture, so damn quickly?!

The Electrrode Grid
This is a lattice of circuits (One for each sub pixel) that can be accessed individually one after the other with a current of varying voltage. The circuits connect to electrodes which set the liquid crystal to light (or not) each individual sub pixel at (depending on the voltage) the required intensity. They of course then light the pixel at the precise colour required. This happens between 50 & 60 times per second per sub pixel (WOW!). Creating the moving image.

The Processor and LCDs are not TV's At All?
What controls this is a computer processor. Not unlike, but never the less different from a PC processor. It is the inclusion of a processor and a relatively flat lattice of electrical circuits which alleviates the need for an electron gun which is what produces the picture in a conventional TV. The absence of an electron gun and its large space requirements is why LCDs are so thin it also technically speaking means that LCD TVs are not really TVs at all but more like monitors.

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