The computer monitor is an output device that is used to display (softcopy) data that is processed on the system unit. A computer monitor is also known as a screen or Visual Display Unit(VDU).
Some types of computer monitors are CRT, LCD, TFT, Plasma, OLED, LED, touch screen, and curved screens. To acquire a new computer screen, some of the features to consider are resolution, size, technology, refresh rate, video connector, aspect ratio, and viewing angle among other factors.
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Types of Computer monitors
Computer monitors have evolved from the bulky big Cathode Ray Tube monitor to the ultra-slim curved screen that we have today. Some of the computer monitor types that you will find in the market include:
1. Cathode Ray Tube (CRT).
These are the oldest types of computer monitors and they used the technology of cathode rays. On the back of the screen, there is a cathode gun that shot rays through a vacuum into the screen. The screen has an anode and material that glows when hit by the electrons.
The rays hit the glowing material and the image is created appropriately. The monitor had a long back side because the front and cathode gun had to be at a distance for it to give the best results.
2. Liquid Crystal Display (LCD).
They used the crystal liquid which is easy to be manipulated and changed when light strikes it. Compared to CRT they are lightweight, slimmer, and use less power. Read about how LCD monitors work.
3. Light emitting diode (LED)
It uses the light-emitting diode as the backlight which makes it slim because it doesn’t need the distance that is required in CRT. They produce images with high resolution, are slimmer, less bulky, and produce less heat and less power.
4. Organic Light Emitting Diode (OLED)
It is the latest technology (an improvement from LED) but still very expensive to produce in bulky. It has an organic substrate that glows when electricity is passed through it. They use less power and they are even slimmer because they don’t need backlight since the substrate can produce light.
Currently, computer screens are manufactured to take instruction from the human touch. An operating system such as Microsoft Windows 8 and above versions was developed to support a touch screen operation. There are 4 main technologies used for touch screens.
- Capacitive touch screen
These screens use the capacitor concept which stores charge. Since the human body has electrical charges when you touch the screen at a specific position you discharge that particular point. The information is then sent to the processor which interprets what needs to be done. They are mostly used on smartphones in today`s applications.
- Resistive touch screen
The resistive screen uses the concept of resistors where it has two layers with a gap between them. For it to be effective the user has to press and not just touch because the two layers must make contact at the point where it has been pressed. When it is pressed the point can be identified and interpreted appropriately. These touch screens can be touched with a finger and any other object that can exact pressure and not a must that it has electrical changes.
- Infrared touch monitors
They have an infrared emitter and receiver which create an invisible grid of rays. When you touch the screen you disrupt the ray transmission which is then recorded as a touch.
- Surface acoustic wave monitor
These touch screens use sound waves to detect the touch. They have transducers and receivers on the opposite corners of the screen. When you touch the screen you disrupt the sound wave which is sensed as a touch command.
6. Plasma display panel
They are flat-panel types of screens made up of small cells containing plasma. Plasma contains charged particles (ions and electrons). When electricity is passed through them they emit light which forms an image. They are not common computer screens because they are more economical for big-size screens.
7. Curved computer monitor
These are replacing flat screen monitors by offering a curved viewing screen. They offer a better viewing angle compared to a flat screen
Factors to consider when choosing a good computer monitor
- Resolution: It is the number of pixels that can be displayed per inch of the screen. The higher the number the more clear the image that is displayed.
- Screen size: This is the diagonal size of the screen. It is what people refer to when they talk about having a computer screen of 21“. A big screen means you can be able to have a better feel of the data without the limitation of the size.
- Aspect ratio: It is the ratio of the length (horizontal) and width (vertical) of the monitor. It determines how the image will be stretched on the screen. The main ratios are 4:3 and 16:10.
- Viewing angle: It is the angle where you can view the image without distortion. CRT screens had a wide viewing angle than LCD screens.
- Power consumption: LCD uses the least power compared to CRT and OLED type of technology. Less power means power is conserved and also it reduces overheating.
- Technology: screen comes from different technology modes as discussed in different types above. The technology will determine the image quality, cost, and user preference.
- Connector video input: latest video connector for monitors is HDMI. However, to be on the safe side you should have a computer screen that supports more than one way of connecting. If you are buying a screen for an already existing system unit make sure you check which is a compatible type of supported connection.
- Ergonomics: most users spend more time on the screen and would like to get a screen design for comfort. Select a screen that has height adjustability, and can change screen brightness and contrast among other designs.
- Refresh rate: this is the rate at which the screen can refresh the displayed image per second. A higher refresh rate means the image will be clear and it will not look like it hangs. It is measured in hertz and the higher the better. Most computer screens have 144Hz.
- Contrast and brightness: contrast ratio is how dark the black part is and how bright the white parts of an image can get. While brightness is the measure of light that the screen can produce.
- Built-in speakers: latest monitor come with an inbuilt speaker that can be used to complement the system unit speakers.
- USB port: USB port is a common connector interface in today’s devices including screens. They can be used to load data without even connecting to the system unit. For future improvement and use, you can select a monitor that has a USB port.
You can read this article that gives details on what is screen resolution, contrast, and how to measure its size.
Types of computer screen connectors
Every computer offers a connection port that allows the computer monitor to be connected to the system unit so that it can receive data being transmitted. Most monitors are connected using a VGA cable. The cable connects the VGA card which translates the information from the system unit into images and text that the user can be able to view. You can read a more detailed article on Video Graphic Adaptors here. Other screen connectors are HDMI, DVI, and DisplayPort.