A note about display tech

A guide to know about common display types and their technologies in present

Overview

In our day to day life, we are using different kind of displays;in our laptop,tablet,mobile phone etc.All of them are displays,but their technologies may differ.You may heard of display technology types like LCD, OLED, IPS, LED etc.In this blog post, the intention is to talk about how a display simply works, which technology trend we have and how to choose a best display for the requirement.In early days we have CRT displays which are very energy in-efficient and bulky displays . With the invention of the LCD technology, the display technology has made many big steps.

LCD (Liquid Crystal Display) display

Let’s talk about LCD (Liquid Crystal Display) display and how it works in-order to understand about other later technologies.

Illustration of how a TFT LCD display works : click here for the source image

LCD display has a fluorescent backlight.In front of that, there are two polarized glasses and there are lines which are perpendicular (90 degrees angled) to the other polarized glass.Hence the light which is emitting through the fluorescent back light cannot get pass through them.So then how do we see the pictures from the display? well there are liquid crystals which act like polarizing agents.These polarization agents changes the direction of the light which comes through the first polarized glass and changes the direction of the light in the relevant areas to go through the second polarized glass.Ok that’s not all the stuff.There are more other things happening here.So in order to make colors, these finally exit light rays are going through RGB (Red,Green,Blue) Light filters (sub pixels) which are attached to every pixel.So this is the basic architecture for the LCD display.Let’s understand other technologies and display types derived from this.

TFT (Thin Film Transistor)

To understand the TFT, we’ve to know about what is Passive Matrix Display.This is the older technology used in the early LCD panels.This means to change the Polarized agent, we’ve to make a electrical signal to change the polarization and it persists as it is.To revert this we’ve to send another electrical signal.Later on engineers able to make a small transistor (thin film transistor) for each pixel.Displays having this technology called as TFT displays.With use of this technology pixels’ polarization agents could be changed effectively and efficiently.So the response time/ refresh rate could achieved at higher rates.With the help of this technology, some other technologies have derived such as TN(Twisted Nematic) and IPS (In-Plane Switching) displays.

LED (Light Emitting Diode) Display

This is the most misunderstood display type among people.It is more descriptive if it says LED back-lit LCD display.This is also a LCD display,but having a LED back light instead of a fluorescent light.This helps to make displays in more thinner form factor.This is a good tech because LED’s save energy.Also nowadays good displays use this LED back light to make Micro-dimming effect .It means when there’s a spot darker,the area of the back light also get dimmed to make a good contrast ratio (ratio between the brightest and lesser brightest value).

OLED (Organic LED) Display

Unlike LED displays, these displays having dedicated LED lights for each pixels.Which can turn off/on when necessary.This saves energy more.These displays are passive matrix displays as discussed above.Can have true black by turning off pixels.These displays has much more brightness level and a good contrast ratio.

AMOLED (Active Matrix OLED) Display

This is also OLED displays, but having thin film transistors to change pixel state.

Summary

Which display suits for you? well each of these technologies have pros and cons.If you are using a laptop, tablet it is good to have a LED back-lit LCD panel (Since OLED displays costly and manufacturing barriers).For a mobile phone it is good to have an AMOLED display.It saves battery a lot and colors are vivid.If you are on to media and professional works,select a monitor with IPS display.these displays having higher accurate colors and high in viewing angles, but slightly less response time/refresh time when compared to TN panels.Speaking of TN panels they are very good for gaming as they are much rich from the refresh rate and color quality.But they are having less viewing angles.If you are on to buy a tv and willing to spend some more money , buy OLED TV.It gives you a better color quality and a contrast ratio.