HOW THE COMPUTER MONITOR/TELEVISION WORKS

Most desktop displays use cathode ray tube (CRT) or liquid crystal display (LCD) technology, while nearly all portable computing devices such as laptops incorporate LCD technology. Because of their slimmer design and lower energy consumption, monitors using LCD technology (also called flat panel or flat screen displays) are replacing the venerable CRT on most desktops.

Now lets take a look on how cathode ray tube (CRT) works. 

-The CRT Monitor that is most likely on your desktop is a cousin of your TV set. Of course they have come a long way since the TV as far as resolution is concerned offering 800X600 or better. Now you may think well why haven't TV's moved up to a better resolution if a computer has such good resolution? TV's are restricted to 525X700 and defined by NTSC (North American Television Standards Commission), surprised? Seems as if everything is made a standard and some bogus organization will make sure they make a buck on it. Well, now how does your monitor make the picture on the screen and do it fast?

In CRT Monitors, the beginning process of the monitor starts with a electron gun. This gun has the job of spraying a focused beam on the glass of the CRT tube, the tube is also in a vacuum. The inside of the glass tube that you are looking at is lined with a phosphorescent material that glows a specific color when excited by the electron gun. Now when the electron gun is firing it is usually through a aperture grill or mask. This mask insures the electron's from the gun hit precise points and make the picture sharper and look great. Now we know when the gun hits the material on the glass it will turn a certain color. We are working with (RGB) red, blue, and green colors that make up individual pixels. If the electron gun hits one pixel with just the right frequency of electrons we will have say a red pixel, little more frequency of electrons we move into a blue and so on. Making all these pixels match up into a image is a big task. So you are probably thinking how does this electron gun go across the screen and does it move this much?

-The electron gun has to update these pixels as much as 70 times a second. This has to be done to keep the phosphors lit. They do burn out if not updated and refreshed often. We need a faster gun then Jesse James for this action. Now, the process of updating the screen is called refresh. You probably have heard that term a few times and is in Hertz on a computer such as 75Hz. This means the monitor refreshes 75 times a second. Remember MHz in CPU's which can calculate information 500 million times a second? Not to slow is it.. Now when the monitor has to refresh a row of pixels we start on the left top side of screen. This is done from the left then goes to the right side, only to be turned off and start all over again at the next row. Now when you have a 800X600 resolution the electron ray gun has to spray 800 pixels per row and do 600 rows. Now do this 75 times a second or more. Kind cool huh? So does this gun just move back and forth from the back of the computer to paint our screen? No, usually for higher rates such as 75Hz and upwards magnetic fields are used to guide the electrons to there pixels more precisely.

Resolution refers to the number of individual dots of color, known as pixels, contained on a display. Resolution is expressed by identifying the number of pixels on the horizontal axis (rows) and the number on the vertical axis (columns), such as 800x600. Resolution is affected by a number of factors, including the size of the screen.
pixel is the smallest element of an image.

As monitor sizes have increased over the years, display standards and resolutions have changed. In addition, some manufacturers offer widescreen displays designed for viewing DVD movies.

How the LCD works

 LCD monitor

We learned in school that there are three common states of matter: solid, liquid or gaseous. Solids act the way they do because their molecules always maintain their orientation and stay in the same position with respect to one another. The molecules in liquids are just the opposite: They can change their orientation and move anywhere in the liquid. But there are some substances that can exist in an odd state that is sort of like a liquid and sort of like a solid. When they are in this state, their molecules tend to maintain their orientation, like the molecules in a solid, but also move around to different positions, like the molecules in a liquid. This means that liquid crystals are neither a solid nor a liquid. That's how they ended up with their seemingly contradictory name.

So, do liquid crystals act like solids or liquids or something else? It turns out that liquid crystals are closer to a liquid state than a solid. It takes a fair amount of heat to change a suitable substance from a solid into a liquid crystal, and it only takes a little more heat to turn that same liquid crystal into a real liquid. This explains why liquid crystals are very sensitive to temperature and why they are used to make thermometers and mood rings. It also explains why a laptop computer display may act funny in cold weather or during a hot day at the beach.