There are two types of monitors: CRT and LC D.
CRT is the old-style "television" type monitor. It is large, heavy, and has a glass screen. CRTs are cheaper, use more power, and have a clearer picture. They also take up a large amount of space on your desk, and cannot be moved easily.
LCDs (flat screen, "TFT," or "active-matrix") are thinner and take up less space, but they have lower picture quality and tend to be more expensive.
Which monitor you get is decided by your overall preference.
Many HDTV sets can be used as giant computer monitors. Make sure they have "PC Inputs." They will have ports in the back or side which allow you to plug in cables from your computer; then you can see the computer screen on the TV. A non-HD TV will show a computer screen as unclear, slightly out of focus. An HDTV should show your computer screen sharply.
There are some points you should know about monitors.
Resolution. This means how much information is on the screen. For computers, resolution is measured in "pixels." One pixel is one small dot on the screen, with a single color. The number of pixels from left to right, and top to bottom is called the "resolution." For example, 1280 x 1024 is a common resolution. It means that there are 1280 pixels fro the left side of the screen to the right side, and 1024 pixels from top to bottom.
You can change the resolution on your monitor. On the Destop, right-click and select "Properties." Click on the far right tab, titled "Settings." The resolution control is on the lower left side. By sliding the control to the left, you can lower the resolution; that will make things appear bigger on the screen, but the quality will be lower. By sliding the control to the right, things appear smaller, but the quality will be better.
- Color Depth. Each pixel can show a number of different colors. The more colors any pixel can use, the better the quality of the picture. The number of colors ("color depth") is measure in "bits." 8 bits means there are 256 colors. 16 bits means there are 65,536 colors. 24 bits is 16,777,216 colors, and 32-bit is more than 4 billion colors. 16-bit color is good enough for most people, and 24-bit color is the maximum number of colors that the human eye could possibly see.
- Progressive vs. Interlaced. This describes how a monitor "paints" the picture on the screen. "Progressive" means that the whole picture is displayed on the screen, all at once.
"Interlaced" means that only half the picture is painted each time the screen 'flashes.' Each flash is called a "refresh." See the image below for an example of interlaced imaging. In the first 'flash,' or 'refresh,' only the odd-numbered lines are painted. In the second 'refresh,' only the even-numbered lines are painted. In two refreshes, one whole picture is shown.
Why interlace? The answer is, "old technology." Interlacing was necessary for the best picture when television was first introduced. Today, it is more of a problem than an advantage, but it is kept because so much of the expensive equipment for broadcasting television still uses interlacing. Even with new HDTV, interlacing can be used. However, progressive is better quality.
Today, progressive is noted with a "p," and interlaced with an "i." For example, the normal TVs you have used all of your lives can be called "525i" because they have a vertical resolution of 525 lines and are interlaced. HDTVs are usually 1080i (1125i) or 720p. Some television sets can show all different standards.
In the future, the quality will probably increase. Right now, NHK is working on something called "Super-Hi-Vision," which will have a resolution of 7680 x 4320--about 4 times better than current Hi-Vision TVs.
OK, so now you know some of the basic points about monitors. So what are the differences between LCD and CRT monitors?
CRT monitors:
- Are cheaper
- Are brighter
- Have clearer, sharper pictures
LCD monitors:
- Are thinner
That's pretty much the difference in advantages. LCD screens are not really that much better in quality, but size is very important. In fact, LCD monitors have two other problems:
- LCD monitors look best when you are looking at it straight-on. If you move to the side, the picture quality fades. CRTs do not have this problem so much.
- LCD monitors have something called "native resolution." The picture looks best at that resolution; any other resolution looks poorer in quality. CRTs can change resolution and keep the best quality.
Let me explain a bit more about LCD "native resolution." A CRT computer monitor has a blank screen, and the pixels are "painted" on to it. When you change the resolution, smaller or larger pixels are "painted." That keeps the quality good.
LCD monitors are different. The pixels are physically set in the screen. If you look closely at an LCD monitor, you can actually see the pixels, as tiny, tiny squares. Here are some pictures to show you:
Here is the corner of my computer screen. You can already see the pixels.
Here is a closer look at the same area. You can clearly see the pixels. But look even more carefully...
In each pixel, there are red, green, and blue elements.
Different mixtures of these colors at different brightnesses can create any color.
OK, so you can see how the pixels are really part of the screen, right? On my computer, for example, there are 1280 pixels from left to right, and 854 pixels from top to bottom. So, the "native resolution" of my LCD screen is 1280 x 854. If I change the resolution, then the picture and the pixels won't match! My computer will try its best to make the image look OK, but it will always have problems, and therefore the quality will be not so good.
That's what native resolution is about.
IMPORTANT: when you get a laptop, you should always test the LCD screen immediately for "dead" or "stuck" pixels. A dead pixel will appear as small black dot on the screen. A stuck pixel will appear as a colored (red, green or blue) dot on the screen (see examples below). These pixels are broken, and they will always stay that color. A few such pixels on a new screen are considered normal, but if you find many, you should consider returning the product and getting a new one.
Below, you can see examples of "stuck" pixels, where one color is always "on." In this case, the green and red elements are stuck.
That was on my old computer. My new computer has one partly-dead pixel. Can you see it below?
You have to look hard, but there it is.
Actually, it's not wholly dead--only the green part is dead.
If that part of the screen shows red, blue, or black, it looks OK.
But white or green pictures have this small black spot.
Here is a closer look:
So, when you buy a new laptop, or a new LCD monitor, try to get a good, careful look at the monitor to see if there are any stuck or dead pixels.
