Difference between CRT, LCD and LED monitors

Technology is evolving at an exponential pace while the outstanding gadgets of the past are becoming obsolete and the new technology is rapidly replacing the old ones. The trend of change for computer users is more than the people belongs to any other field of life. The computer monitors have a special role in the use of the computer as the user gets every output on it. In order to give a better experience to the user, advanced technologies are being introduced and the new monitors are light in weight, have better resolution, have vivid colors and are harmless to the eyes. If you’re thinking to buy a new monitor, then you must know the difference between LCD, LED, and CRT monitors.

Cathode Ray Tube (CRT):

cathode ray tube (CRT) Structure

Cathode Ray Tube is an abbreviation for Cathode Ray Tube. CRT monitors and televisions are traditional monitors using this technology. In CRT displays, the image is produced by the firing of electrons from the back of the phosphor tube towards the center of the screen.

The phosphorus emits light when heated by the electron, which is then projected onto a screen. The color you see on your screen is made up of a combination of red, blue, and green light sources.

Components:

Electron Gun

An electric gun consists of a number of components, most notably a heater filament (heater) and a cathode. This device emits a beam of electrons that is focused onto the face of the CRT to produce an electron beam.

Control Electrode

The electron beam is turned on and off by this switch. An electron tube’s electrodes can alter the current flowing between two or more electrodes. This type of device is simple to use. Despite this, people often use the term without fully understanding it. Basically, the electrodes function as conduits for electrons to move through them.

Focusing system

An oscilloscope uses the same method of focusing as a compound lens system to refract light beams. Since light beams can be focussed by changing the focal length of the system, electron beams can also be focused on the screen, creating a fine point of illumination. CR Tubes have electrostatic field lines and equipotential lines, and it is necessary to know the nature of both to comprehend the electronic lens system.

Deflection Yoke

A beam control system is used to direct a beam of electrons. When the electron beam passes through the area, it will be bent by an electric or magnetic field created by the device. A scan generator or sweep generator is attached to a yoke on a conventional CRT. As a result of the connection between the deflection yoke and the sweep generator, an electrical or magnetic potential is created.

Phosphorus coated screen

In every CRT, phosphors are embedded inside the front surface. Plasmophors glow when they are struck by an electron beam with high energy. It is called phosphorescence because it describes the light that is given off by a phosphor when it is exposed to an electron beam.

Advantages:

  • Compared to other display technologies, it is less expensive.
  • Reaction time is fast.
  • The image can be resized without resizing the resolution, geometry or aspect ratio.
  • Highest possible pixel resolution.
  • It produces more colors.
  • CRT can also be used in dim or low-light conditions.
  • All professional calibrations rely on them because they produce a very dark black and grayscale.
  • Reflecting the light on the monitor increases its brightness.
  • Motion artifacts are not present and response times are fast.

Disadvantages:

  • Large back and occupying desk space.
  • The LCD is less bright than a very bright environment, so it’s not suitable.
  • Bulky, heavy, and large in size.
  • produce a lot of heat while consuming a lot of electricity.
  • Edge geometries are incorrect.
  • Approximately 50-80 Hz flickering.
  • Electromagnetic fields both DC and AC can be hazardous.

Liquid Crystal Display (LCD):

Liquid crystal displays are used to display images on a computer screen using liquid crystal technology. Laptops and flat-panel monitors are common examples of LCD displays. Cathode-ray tube monitors have been replaced by LCD displays. CRT monitors were once considered the best picture quality among LCD models as they were the previous standard. Having improved and continuously advanced over the years, LCD technology is considered the clear leader today.  In terms of color and picture quality, as well as delivering high resolution, it is impressive. Furthermore, LCD monitors may be produced at a lower cost than CRT monitors.

Components:

Liquid crystal display structure

The main component of a liquid crystal display is liquid crystal material. Different liquid crystal materials are used in different devices. The majority of liquid crystals contain several different liquid crystal types, sometimes even more than 10.

Polarizer

Plastic film material is coated with an optical pressure-sensitive adhesive to make the light sheet. Polarized light is also known as polarized film. Polarized films can be applied to the surface of liquid crystal cells. When it is used, the front polarizer is covered in a protective film that needs to be removed. Polarizers are afraid of high temperatures and humidity, which can cause depolarization or blistering when exposed to those conditions.

Glass Substrate

Evaporating a thin transparent conductive layer made of zn203 or sn02 is applied to a float glass production thin sheet to create thin and transparent conductive layers. Transparency is achieved by transforming the pattern into a transparent one. Scrap will be taken if the vacuum device gets scratched, cut, or corroded.

Advantages:

  • Featuring a slim profile.
  • The screen emits no radiation.
  • Anti-glare technology makes it better under bright conditions.
  • Weight is lighter than the size of the screen.
  • Low power consumption makes it energy efficient.
  • Due to a wide brightness range, a high peak intensity produces extremely bright images.
  • Reducing electromagnetic fields, electric fields, and magnetic fields.
  • The distortion of geometry is zero.
  • Contrasting beautifully.
  • The flicker rate is low.
  • In a panel with native resolution, images are perfectly sharp.
  • In contrast to other technological advances or systems, pixels per square inch are usually higher.
  • Does not tend to burn in on the screen.
  • Increases and decreases in air pressure have not affected it.

Disadvantages:

  • Prices are slightly higher than CRTs.
  • Portals to other dimensions are not possible.
  • Feel the effects of motion blur.
  • Frequently refreshed.
  • Backlights change color slightly as they age.
  • Fixed aspect ratios and fixed resolutions.
  • Colors like black and very dark gray cannot be produced.
  • Angles of viewing are restricted.
  • Responding too slowly.

Light Emitting Diode (LED):

A flat screen or flat-panel computer monitor or television is known as a LED monitor, short for a light emitting diode monitor. These monitors are small and light, with a shallow depth. It is the backlighting that makes this monitor different from a standard LCD. In the early days of LCD monitors, the screens were illuminated by CCFLs instead of LEDs.

It is very important to explain all of the components of an LED before talking about how it functions.

Components:

LED working principle

Post and Anvil

LEDs consist of two conductors that can be used to provide voltage to the LED. Positive and longer leads are known as Post leads, while negative and shorter leads are known as Anvil leads. Posts and Anvils are responsible for polarizing the two leads. As for the Anvil, it holds the chip physically, acts as a heat sink, and acts as a target for light to be directed to.

Semiconductor Die

Essentially it’s a tiny piece of semiconducting material from which an accurate circuit is constructed. The heart of any electronic device is the integrated circuit since it consists of several integrated circuits.

Reflective Cavity

An important aspect of LEDs is light extraction. The primary purpose of this component is to increase the brightness of LED light by focusing its light on just one point.

Epoxy Lens

There are three essential functions for this LED component. Here they are:

  1. This semiconductor is specifically designed to allow the majority of light to escape.
  2. LED semiconductors are protected from outside elements by it.
  3. The light is the focal point.

Advantages:

  • Featuring a sleek design.
  • Image quality is brighter and sharper.
  • It’s Better in Color.
  • Photographs images are Flickr-free.
  • The picture quality is better (the picture is true black).
  • There isn’t any motion delay or lag at all.
  • Less environmental impact and longer lifespan.
  • Powered by a lower amount of energy.
  • Larger viewing angle (generally 175 degrees).

Disadvantages:

  • Compared to traditional lighting, LEDs cost more.
  • Temperature and age affect the color of LEDs.
  • Compared to LCDs and Plasmas, LEDs are much thinner.
  • The contrast ratio is inconsistent.
  • Costs much more.

Comparison Between CRT, LCD, and LED Display

The display quality of LED is age and temperature-dependent while CRT has no such kind of issue. Moreover, LED is expensive and inaccessible to everyone. Similarly, the LCD monitor doesn’t support the black and white feature and also has less response time. On the contrary, CRT gives true black color and has a high response time. CRT monitors are cheap and accessible to everyone.

Comparison Chart

BASIS FOR COMPARISONCRTLCDLED
RepresentCRT represents “Cathode Ray Tube“LCD represents “Liquid Crystal Display“.LED represents Light Emitting Diode
CompoundsVacuum glass tube, electron gun, phosphor screen,  deflection plates.Glass plates, internal light source; nematic liquid crystal.Post and Anvil, semiconductor Die, Reflect cavity, epoxy lens
SizeCRTs are bulky, heavy, and large.LCDs are thin, light, and compact.LED is light, compact, and Thinner.
WeightHeavierLighterThinner
Power ConsumptionHigh power.Low power.Lower power.
ColorBlack.White.True Black.
Image RetentionCRT lacks image retention.LCDs have image retention.It retains images.
CostLess expensive.More expensive.Most expensive.
Image FormingUsed Electron GunUsed Liquid crystalsUsed Light Emitting Diode  
ResponseGood response.Slow response.Sufficiently fast response.
BenefitsPanels are lighter than plasma; more energy efficient; emits less; thinner; light; radioactive; no bleeding or smearingEasy to move; picture quality is Good; wide viewing quality; cheaper; multiple resolutions; sharper image quality.Sleek design; Image quality is brighter and sharper; Flicker-free Images; There isn’t any motion delay or lag at all; Larger viewing angle (175 degrees)
LimitationsFilm-like picture; slow refresh rate; narrow field of view; blacks and brights; image persistence is possible; pixel death is also possible.Heavy, small displays; outdated technology; easily burnt inTemperature and age affect the color; LEDs are much thinner; LEDs cost more.
Where UsedUsed in old computer monitors and Televisions.Used in flat screens.  Used in flat panels display.

Conclusion

CRT, LCD, and LED have their own specifications, pros and cons. Before buying the monitor, one should be particular about his or her requirements. Notice your budget, space in the home and core features on which you can’t compromise. No doubt, it will be a lucrative deal if one buys the monitor after analyzing the above-mentioned features.

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