It is important to make a clear distinction between the terms monitor and screen: a monitor is a device that includes a screen. Some monitors have inbuilt speakers for example. Nevertheless, a monitor/screen is the main output device on almost any computer.
In this post:
Required knowledge:
1. Size
The physical size of a screen is expressed in inches diagonally across the screen, for example, 32″.
2. Resolution
The resolution of a screen is measured in the number of pixels across by the number of pixels down, for example, 800 x 600, or 1024 x 768.
3. Ratio
The ratio describes the physical shape of the screen. It is expressed as a ratio comparing the number of units of width to the number of units of height of the screen.
A 1:1 ratio monitor would be a square monitor.
A 16:9 ratio monitor would be a widescreen monitor.
A common monitor resolution of 1024 x 768 has a 4:3 ratio.
4. Colour Depth
This is how we express how many colours a screen can display. 1-bit color is usually simply black and white (2 colours). With True color (24-bit), 24 bits almost always use 8 bits each of R, G, and B. 224 gives 16,777,216 colour variations (more colours than the human eye can detect!)
“The colour depth of an image is measured in bits. The number of bits indicates how many colours are available for each pixel. Colour depth is only one aspect of colour representation, expressing the precision with which the amount of each primary can be expressed.” [1]
https://en.wikipedia.org/wiki/Color_depth
5. Connections
A computer device has a Video Graphics Array (“VGA”) port. This could be integrated into the motherboard, or in the form of an expansion card.
The High-Definition Multimedia Interface (“HDMI”) interface is capable of transferring not only video but also audio signals to a device. This makes it ideal for connecting digital projectors and monitors that include speakers.
Both VGA and HDMI are interfaces between the computer device’s display controller and the monitor/projector.
6. Picture technology
6.1 CRT
The first television sets used Cathode Ray Tube (“CRT”) technology to create images. A CRT is a vacuum tube containing electron guns. Each electron gun emits a beam of electrons at a phosphorescent screen. The electrons are deflected by magnets, thereby directing them to specific points on the inside of the screen. The phosphorous emits light when struck by the electrons.
6.2 LCD
Original Liquid Crystal Display (“LCD”) created monochrome characters on back-lit displays using seven-segment displays such as those seen in digital clocks & calculators.
6.3 LED
Light Emitting Diode (“LED”) technology is used in modern laptops, computers & smartphone screens.
A light-emitting diode is a small electrical component that lights up when current flows through it.
Read more about diodes.
7. Next steps
Take a look at Data projectors.
References:
- Wikimedia Foundation. (2023) Color depth. Available at: https://en.wikipedia.org/wiki/Color_depth (Accessed: 18 October 2023).
- Wikimedia Foundation. (2023) Light-emitting diode. Available at: https://en.wikipedia.org/wiki/Light-emitting_diode (Accessed: 18 October 2023).
- Wikimedia Foundation. (2023) Cathode-ray tube. Available at: https://en.wikipedia.org/wiki/Cathode-ray_tube (Accessed: 19 October 2023).