Cathode Ray Tube (CRT) Monitors
The first computer monitor ever made
The cathode ray tube (CRT) was the first technology that made it possible for us to view recorded or live images on a screen. In 1859, a German mathematician and physicist, Julius Plucker, identified cathode rays, which was the first step in the creation of the CRT monitor. In 1931, Allen B. Du Mont invented the first reproducible CRT, used in television sets.
Until the early 1980s, CRTs were known as video display terminals and were actually physically attached to the computer itself. The keyboard was also attached. The screens could only display one color and flickered badly. In 1981, IBM took hold of the computer market when it invented the Color Graphics Adaptor, which could display four colors with a resolution of 320 x 200 pixels. They introduced the Enhanced Graphics Adaptor in 1984, which was capable of producing 16 colors and had a resolution of 640 x 350.
CRT monitors have come a long way over the past 20 years. Although the displays are still bulky, the larger screens - 21 inches or bigger - still produce a better image than the liquid crystal display (LCD). Today, video game enthusiasts and graphic designers still swear by them because of their better response times. LCD monitors come equipped with only one resolution that cannot be adjusted without hurting image quality, so any images that move quickly onscreen or require a high resolution become blurred or distorted. LCD monitors are getting better, but high quality comes with a high price tag.
How the CRT works:
- CRTs have "shadow masks," which are thin metal screens with tiny holes. Three electron beams pass through the holes, focusing on either red, blue or green phosphor dots - organic material on the surface of a screen. The shadow mask controls the intensity of the beams to create the appropriate colors and images. Some monitors use Trinitron technology, which was created by Sony and uses an aperture grille. Electron beams pass through the aperture grille - filled with tiny wires - to the face plate. Monitors that use this technology tend to be more expensive.
- CRT monitors require information in analog form via the transmission of electric signals or waves. Once the information is put into electronic form, it is sent through a VGA cable, which is connected from the computer to the monitor.