Computer Monitors

Computers and the Internet have changed and continue to change the world. The computer is the vehicle that is introducing the world to technological advancements and medical and social achievements. Computer monitors are the windows of this new world and they continue to improve in quality and performance. The computer monitor of ten years ago is not the same visual display unit it is now, but it’s still a piece of electrical equipment which can display a wide range of images from the video output of different computers, without creating a permanent record. The display device used to display images today is a thin film transistor liquid crystal display also known as TFT-LCD. The older monitors used a CRT or cathode ray tube.


Measuring computer monitors is a bit confusing. The measurement is based on the CRT television method, which was used when round picture tubes were popular.

They were circular, so they only needed a diameter measurement to describe the tube size. When CRT tubes were manufactured as rectangles this method was still used, so the distance between two opposite corners is given as the screen size, even though it does not take into account the aspect ratios differences of monitors with the same diagonal size. The shape of a diagonal area decreases as it becomes less square, so the measurement system is a not accurate, in terms of square inches for monitors with the same diagonal size. Another issue with screen size is the size of the imaging element, which is distorted by media advertising campaigns. Viewable size is more important than measuring the image element size, which can be hidden behind the case’s shroud.


Image technology continues to improve. TFT-LCDs are the most popular monitors, the old passive LCDs had a slow response time and the contrast was poor. They started to be replaced in the mid 1990s. Other types of visual displays include the Penetron and the Plasma Display along with the old CRT.


The LCD is light, compact and rugged and there is no geometric distortion, but it has a low contrast ratio, uneven back lighting and slow response times, which can cause ghosting. The Penetron Military Aircraft Display has high contrast ratios and is extremely sharp, although there are only four color displays. The Plasma also has high contrast ratios and a high speed response, excellent color and a low black level, but it has lower resolution on a large screen and there is a noticeable flicker when the display is viewed close range.


Today’s computer monitors can display an infinite number of colors by continuously changing the intensities in the RBG color space, which is the red, green and blue analog video signals. New connectors are replacing both analog and digital signals with digital only video signals, which have integrated data and video connections. Other new features include multiple monitor capabilities, which can show the identical image called mirroring and extension monitoring, which shows different images but it does require extra hardware and software support. There’s no doubt than computer monitors will continue to improve in quality as well as functionality. The touchscreen technology is opening the doors for another giant leap in the virtual display industry.