Monitors are used to view your data on a computer. The characteristics of your monitor are very important for your system performance since the quality of your video will significantly affect your computing experience.
Most monitors today consist of a picture tube and electronic control circuitry which are used to transfer the signal to the screen. There are some monitors that do not use a picture tube, but use electronics to display information. These monitors are more expensive and are not usually very large, but are primarily used for smaller computers such as notebooks and laptop computers. We will not discuss the flat video displays in this section at this point in time.
The primary and most expensive component in a standard monitor is its picture tube. The most important characteristics of a monitor generally refer to picture tube specifications although other circuitry can also be important in providing picture clarity. A picture tube is basically a large vacuum tube with a phosphorescent coating on the front of it. At the back of the picture tube is a large electron gun ( actually 3 guns ) which shoot(s) electrons onto the phosphorescent coating at the front of the tube. When the electrons strike the coating, the coating glows. The coating provides the primary colors which are green, red, and blue. These component colors and their combinations can be used to make every other possible color combination. There is other circuitry which works with the gun to direct the electron gun to the proper color at the correct time, and to direct the gun to the correct location on the screen depending on the phase of the video signal that is being sent to the monitor. There is magnetic circuitry which is used to bend the electron beam to strike the appropriate area on the screen. This is referred to as deflection.
The yoke is an electromagnetic coil used to guide the beam to its intended location. The color pattern on the phosphorous appears like the three colored circles shown on the left side of the drawing below. There are many of these color patterns on the screen. The closer the groups of these three patterns are, the better the resolution of the monitor can be. Monitor resolutions refers to the number of lines per inch that can be seen on the screen. It is rated in vertical (up and down the screen) and horizontal (left and right) terms.
Some of the most important specifications on the monitor are:
- Screen size - Expressed in inches, it is the approximate size of the picture tube when measured from the lower left corner to the upper right corner.
- Spacing - Expressed in dot pitch. This is the description of how close the three color patterns are spaced apart in the screen. The smaller number, the better.
- Maximum resolution at a specific frequency. This refers to the amount of pixel resolution viewable on the screen at a specific scan frequency. The higher the pixel resolution at a higher given scan frequency, the better the monitor is. Generally I look for 19 inch monitors that will support 1200X1600 pixel video resolution at 80Hz. Currently a good monitor for the price is the LG Electronics 995E for under $300.00 at pcnation.com.
How dot pitch spacing can be deceiving
Different manufacturers and vendors rate dot pitch different ways. There are actually three characteristics of dot pitch. They are: