CRT is an analog type display that was popular two decades ago, while LCD is a digital type display and is considered as the successor of CRT monitors. But LCDs are not superior in every aspect with CRT monitors. In this article, we gonna look into each technology and the differences between them.
CRT (Cathode Ray Tube)
CRT, Cathode Ray Tube is an analog display technology that we commonly used a decade ago. It creates images by projecting electrons on a phosphor screen. And when an electron beam hits the screen, the place shines and creates colorful lights.
How do CRT Displays Work?
A CRT display has a vacuumed tube (a tube with no air in it). And it also has an electrode in the back of the vacuum tube that releases electrons. Because it emits positively charged particles, it is referred to as the cathode gun (Because electrons are negatively charged, we know that they’re negatively charged particles). The electron gun is made up of an array of components which include the heater filament (heater) and the cathode.
Screens are coated in phosphor that glows according to the strength of the beam. When the cathode gun is activated and electrons are fired into the screen, the beam of electrons goes towards various areas of the screen. Line by line, the deflection takes place by covering the whole screen.
The brightness of the beam is responsible for the brightness of the image. If your image is much brighter, the electron gun fires a strong electron beam. And if your image is a dark one, the electron gun fires a weak electron beam.
There are both black and white CRT displays and Color CRT displays.
Note: You can’t see cathode rays in your naked eye. However, when these electron beams hit the phosphor screen, it shines can create color light.
LCD (Liquid Crystal Display)
LCD, Liquid Crystal Display is a digital display technology made of liquid crystals that function through blocking the light.
An LCD display is composed of two pieces made of polarized glasses that have the liquid crystal substance between the two. And there is a backlight which is important because, without the backlight, we can’t see the image.
If the image is black, the LCD panel block all the light coming from the backlight. If the image is white, the LCD panel allows all the lights from the backlight to come through the screen. If the image has other colors, it filters the light and gives the required color.
Difference Between LCD and CRT
|Basic Concept||Uses cathode rays to shine a phosphor screen to display the image||Uses color filters in different levels to display the image|
|Display method||Pulsed method||Sample and hold|
|Common display ratio||4:3||16:9 (widescreen)|
|View angle||No difference with the angle||The view angle is limited|
|Black level||Shows true black color||Can’t show true black color|
|Motion blur||No blur at motion||Blurs image at motion|
|The display to body ratio||Low||High|
|Display shadows||Create marks in some cases||Never creates marks|
|Dead pixels||No dead pixels||In some cases|
|Power||Consumes more power||Consumes less power|
|Weight||Higher weight||Lesser weight|
|Lifespan||Around 25000 hours||Around 60000 hours|
- CRT uses an analog technology while LCD uses digital technology to display the image.
- 4:3 display ratio was the most popular one back in two decades ago. Because of that, most of the CRT displays have a 4:3 ratio. However, it’s not only on CRT monitors. Back in the day, even LCD monitors came in a 4:3 ratio. Today, most LCD displays come in a 16:9 ratio, which is known as widescreen displays.
- The manufacturing cost for both displays are similar. But, because of low demand, CRT displays are super cheap compared to LCD ones.
- CRT displays have the ability to show true black color while LCD displays can’t. Because, even the all the colors come through a pixel is blocked, the other lights coming through neighboring pixels affect the black color. So LCD usually gives a grey tone instead of black.
- Weight and the size compared to the display size is huge in CRT monitors. But in LCD displays are flat and even the display to body ratio is increasing every year.
- When it comes to power consumption, CRT displays consume more power compared to LCD monitors.