Almost all of us have watched television at some point in our lives. And, most of us have a general understanding of how television works – images and videos are displayed on a screen by shooting electrons at it, which makes the pixels light up and create the image. However, there is a lot more to the process than just that. In order to create an image, television screens need to be able to control the number of pixels that are lit up and the intensity of the light. There are two main ways that this is done – using cathode ray tube (CRT) screens or liquid crystal display (LCD) screens.
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) Technology
A decade ago, CRT, or Cathode Ray Tube, was a commonly used analog display technology. It works by projecting electrons onto a phosphor screen. When an electron beam hits the screen, the phosphor lights up, creating a colorful image.
CRT technology was used in a variety of devices, from televisions to computer monitors. It was also used in early video game consoles, like the Atari 2600. While CRT technology is no longer used in today’s devices, it was an important stepping stone in the development of modern display technology.
How do CRT Displays Work?
A CRT display has a vacuumed tube (a tube with no air in it). Plus, 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). And 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. Then, 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. Moreover, black and white CRT displays use a phosphor to emit light, while color CRT displays use three phosphors to emit red, green, and blue light. The human eye perceives these three colors when the brain combines the light from the three phosphors.
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) Technology
LCD, Liquid Crystal Display is a digital display technology made of liquid crystals that function by blocking the light. If you have an LCD screen, then you may have noticed that the image on the screen is made up of tiny dots of color. These dots are called pixels, and each pixel is made up of three smaller dots of color. One dot is red, one dot is green, and one dot is blue. Together, these three colors make up the colors that you see on the screen.
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 blocks 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|
The two main types of display technologies used in monitors today are CRT and LCD. CRT uses analog technology while LCD uses digital technology to display the image. Both have their pros and cons, but LCD is the more popular technology today.
When we think of older technology, we often think of big, bulky CRT monitors with a 4:3 display ratio. So, this was the most popular ratio two decades ago, and because of that, most CRT displays were made with a 4:3 aspect ratio. However, it’s not only CRT monitors that had this ratio. Back in the day, even LCD monitors came in a 4:3 ratio. Now, most LCD displays come in a 16:9 ratio, which is known as widescreen displays.
Why did the 4:3 display ratio become so popular? Well, back in the day, most computer users were using their computers for work-related tasks. Word processing, spreadsheet work, and other business applications were the norm. Therefore, the 4:3 ratio was well-suited for these types of applications.
However, as time went on and computer usage became more diversified, the need for a wider display became more apparent. This is especially true for media-related tasks such as watching movies and playing video games. The 16:9 widescreen ratio is much better suited for these types of activities.
If you’re still using a 4:3 monitor, you’re not alone. Many people still use this older technology. However, if you’re in the market for a new monitor, you’ll likely want to go with a widescreen display.
The costs of manufacturing CRT and LCD displays used to be quite similar. However, the cost of manufacturing LCD displays has fallen significantly in recent years, making them more affordable than ever before. Thanks to advancements in technology, LCD panels can now be produced more cheaply than CRTs, making them the preferred choice for many consumers.
Weight and the Size
CRT monitors are typically much larger and heavier than their LCD counterparts. This is due to the fact that CRT monitors use a cathode ray tube to produce the image on the screen. This tube takes up a lot of space, which results in a larger overall footprint for the monitor. Additionally, the heavy glass casing of a CRT monitor can add a lot of weight.
LCDs, on the other hand, are much thinner and lighter, and even there are many display size selections. Moreover, LCD display-to-body ratio is increasing every year.
When it comes to power consumption, CRT displays consume more power compared to LCD monitors. In CRT monitors, there has to be a heated filament so electrons can flow off of the cathode. In order to maintain the heated filament, the CRT monitor requires a high voltage power supply. In addition, the CRT monitor has a yoke coil that needs the power to move the electron beam back and forth on the screen. When the CRT is turned on, it uses a small amount of power to keep the cathode warm.
One of the benefits of LCD monitors is that they are more energy efficient than CRT monitors. LCD monitors do not have a heated filament or yoke coil, so they do not require a high voltage power supply.
LCD displays offer many advantages over CRTs, including lower power consumption, thinner form factors, and sharper images. Thanks to their lower manufacturing cost, LCDs are now the preferred choice for many manufacturers.