Difference Between LCD and LED

What is LCD and LED?

LCD

 LCD stands for liquid crystal display. Liquid crystal is a kind of material that is neither liquid nor a solid, it comes in between these two states of matter. It has properties similar to that of the crystallised solid. The arrangement of molecules is in a fixed pattern however they are not fixed in shape or form. 

LED

LED stands for light-emitting diode and it is a semiconductor light source that emits light when current flows through it.

It is a type of flat-panel display that uses an array of light-emitting diodes as pixels for  displaying images.

It comprises two sheets of polarizing material with a liquid crystal solution between them. 

Full Form of LCD and LED

LCD stands for liquid crystal display.

LED stands for light emitting diode.

LCD and LED

LCD

This technology is used in laptops, digital clocks, watches,  digital cameras, watches, etc.

There are three types of LCD TVs

  1. Flat screen LCDs

  2. Front projectionLCDs

  3. Rear projection LCDs


LED

They are usually found in smartphones, televisions, computer monitors and instrument panels and use a liquid crystal display panel to control where the light is displayed on your screen.


There are 3 types of LEDs based on their backlighting methods:

  1. Edge-LEDs

  2. Dynamic RGB LEDs

  3. Full-array LEDs

Working Principle of LCD Monitor

To display anything on the screen, three major components are necessary, they are:

  1. Light: A source through which you see the objects.

  2. Color: To view the objects in different colors otherwise everything on the screen will appear white.

  3. A way to control the light and color on the screen.


These three components are found in LCD. 

LCD  uses liquid crystals in its main form of functioning to produce a visible image


Principle

 It is a type of flat-panel display technology that uses diodes, small cells and the ionised gases for the production of images.

LCD works on the principle of blocking light.

It also works on the modulating property of light where the light modulation is the technique of sending and receiving the signal through the light. 


Working

A light is non-polarized by nature when passed via a plane. It scatters in different directions and phases as you can see in the image below:

[Image will be uploaded soon]


On placing the polarization filter (either horizontal or vertical), and plassing the same light through this filter. 


The filter would polarize the light in one phase and produce a clean polarized light which you can see on your computer and TV screens.


The image below shows the polarized light:

[Image will be uploaded soon]


In LCD displays, light emitted from backlight passes via a vertical polarization filter after going through the liquid crystal element, this liquid crystal element twists this light wave. The vertically polarized light then turns to a horizontal polarized light. This horizontally polarized light passes via the horizontal polarization filter allowing the passage of light. Hence the light is visible to us.The voltage we apply to the LCD is applied in such a way that the crystal mechanism of the light is removed and the light acquires a straight pattern. Due to this, the vertical polarized light will come out vertically only, however the horizontally polarized light will be blocked and we won’t see any light in this case. This is how LCD works on the principle of blocking light.


The image below show the working of LCD:

[Image will be uploaded soon]

Difference between LCD and LED


Sl No.

LCD

LED

1

Stands for liquid crystal display.

Stands for light-emitting diodes.

2

LCDs use fluorescent lights. 

LEDs use light emitting diodes. 

3

The fluorescent lights in an LCD TV are always placed behind the screen.


The placements of the lights on an LED TV can differ which means light -emitting diodes can be placed either behind the screen or around its edges.

4

LCD requires mercury for their production causing harm to the environment.

LEDs use no mercury and are therefore environment friendly.

5

An LCD is cheaper than an LED.

LEDs are costlier than LCDs.

6

LCD screen size comes in the range of 13-57 inches.

LED TVs can be up to 90 inches and they are much slimmer than LCD TVs. 

7

LCD TVs are the most efficient type TVs as they can help you save as much as 30-70% more electricity than any other TV type.

LED TVs consume very less energy so there is almost 50% reduction in power consumption.

8

LCD TVs use the cold cathode fluorescent lamps (CCFL) for backlighting. The picture quality of LCD TV is noticeable in scenes with high contrast, as the dark portions of the picture may appear too bright or washed out.

LED TVs use energy-efficient light emitting diodes for backlighting and can provide a clearer, better picture, a thinner panel, and lesser heat dissipation than a customary LCD TV.

FAQ (Frequently Asked Questions)

1. What is the liquid in the LCD screen?

Liquid crystal displays (LCDs) is a technology comprising liquid crystals that are activated by electric current. The basis of this technology is the liquid crystal, a substance made of complicated molecules (crystallized solids). Like water, liquid crystals are solid at low temperatures, and they melt as you heat them.

2. What are the advantages and disadvantages of using LCD TVs?

There are several advantages and disadvantages of using an LCD TVS that are as follows:

 Advantages:

  1. They are lightweight, thin and compact.

  2. It has no geometric distortion.

  3. Perfect sharpness.

  4. Low power dissipation.

  5. Screens are perfectly flat.

  6. No screen burn-in effect.

Disadvantages:

  1. Lifespan gets affected by Direct current flow. Therefore, Alternating current is supplied for its longevity.

  2. In high temperature environments, the contrast gets affected.

  3. More electricity consumption.

  4. Not suitable for very bright environments like in sunlight, you can’t view the perfect images.

3. Which is a better LCD or LED?

Since the power dissipation is less in LED TVs. They can run with a greater energy efficiency. They provide a clearer and better picture than the general LCD TVs because these TVs work with a color wheel or distinct RGB (red, green, blue) colored lights to produce more realistic and sharper colors.