Looks like we made it. Here we are at the final hardware component (at least for the time being) that we?re going to analyse: The Computer Monitor.

Nowadays, if you buy a computer you will usually be supplied a flat-panel monitor. Before I deal with those, lets take a look at the older ones that many earthlings have.

Older monitors, known as CRT (Cathode Ray Tube) Monitors, have a number of things against them. Firstly, their physical footprint (the amount of desk real-estate they occupy). Second, their method of display, which can contribute to eye health issues. Its going to be difficult to explain this method and try to stick with standard earthling language, but here goes.

Within a monitor, there are three electron guns, each firing from the rear if the monitor (i.e. near the power cable), onto the back of the monitor screen, where there is a sheet of thin sheet of conductive, magnetic material.

The three guns are responsible for bombarding the back of the monitor glass with electrons, and the magnetic outer edge of the glass ?bends? the electrons such that they hit the screen at a particular point.

The physics at play here is pretty precise. Where it hits the screen, there are three tiny holes in the magnetic sheet, one for each primary colour. The strength of the signal, and is frequency, will determine the colour that gets displayed on our side of the screen.

Okay, the issue with this is the distance between each of the three tiny holes: Known as aperture grille pitch (or dot pitch), it is measured in fractions of a millimetre (i.e. an average dot pitch might be 0.24mm).

This might appear a very short distance, but your eye is an incredible piece of engineering and can detect it.

Additionally, monitors have what is know as a ?refresh rate?, which is a measure of the number of times the signal from your computer?s video card, is resent, per second, to your monitor.

This is measured in cycles-per-second (known, from a previous article, you will recall, as hertz).

The rule goes like this, the slower the refresh-rate, the more likely your eye is of spotting it, which will translate as discomfort of some kind. Refresh rate can normally be altered to the fastest possible, but be careful that your video card is not more capable than your monitor, because it is possible to break your monitor by attempting to increase its refresh-rate beyond its capabilities.

Finally, for CRT monitors, there is an extremely low level radiation output from the monitor.

Its so low to be almost unnoticeable, however, extended exposure to, for example, heavily pregnant women should be avoided.

Flat-panel monitors on the other hand have no associated radiation, no issues for eye health (save the usual advice to avoid any extended time whereby you are staring at a computer monitor), and take up lots less room.

From a purely selfish perspective, IT people prefer flat-panels, also, because, for example, I have strained my own back just three times in 20 years in the IT industry, and each time was whilst carrying a CRT monitor.

The technology at play here is the usual Liquid Crystal Display (LCD) that we all know and love and has been maturing for over twenty years, since it wad first employed on digital watches in the 70s.

Nowadays, we utilise specialist technology called Thin Film Transistor (TFT), in which one of four individual transistors are used for each picture cell (pixel), instead of the three tiny holes utilised in the CRT model. Critically these are individual, so there is no issue with the eye detecting slight gaps between different colours displayed.

What happens is that a light source is produced behind the TFT, this is usually a fluorescent source, as we are used to with tube technology in offices today. The light then passes through the TFT matrix, a wiring assembly, similar to a grid, which is spread across the glass cover of the light source.

Today?s monitors are known as active matrix LCDs, which means that a separate signal is delivered to each individual pixel.

In front of the matrix, is the actual liquid-crystal suspension, which has an electrical field applied to it to alter the chemical properties of each liquid crystal cell to alter its light absorption properties. Such an alteration modifies the light produced by the back-light source, which will eventually result in the visible display, though there is a further colour filtration activity before it gets to us.