#7_What is LCD and how does it work?

WHAT IS LCD?
LCD's full form is Liquid Crystal Display ". It was first discovered in 1888. Since then, it has been used to gradually increase its usage. This is a technology that is used according to the display. Where you can do many things like application status, display values, program debugging. Like LED and Plasma technology, the display also has very thin compared to CRT technology. LCD consumes very little power compared to LED and Gas-display because it works in the principle of blocking light and not emitting

An LCD is usually made of a passive matrix or an active matrix display grid. These active matrix LCDs are also called thin film transistor (TFT) display. In the same passive matrix LCD, which are the grid of conductors, they are located on all the intersection of the grid with the pixels. Current is sent across two condensors on the grid for any pixel. In an active matrix, there are one transistor at all pixel intersection, so that they need less current to burn the pixel.

For this reason only the current can be switched on and off in active matrix display so that screen refresh time can also be improved. Dual scanning is present in some passive matrix LCD which means that it can scan the grid twice, at the same time as the only one with the help of original technology, it was only scan once. But still active matrix is ​​still a superior technology.

WHAT IS Principle of LCD?
The backlight also provides light source from behind the LCD screen. This light is polarized, meaning only half light through the liquid crystal layer through shine. This liquid crystal is made from some solid part, made of some liquid substance, which can be easily twisted, by applying electric voltage. They block the polarized light when it remains off, but reflects red, green and blue light when they are activated.

All LCD screens have matrix of pixels which display the image on the screen. Previous LCDs used to have a passive matrix screen, which used to control individual pixels by sending the charge in row and column. Because very limited charges could be sent in every one second, images in the passive-matrix screen appear blurry when the images were sent across the screen. Nowadays, modern LCDs use active-matrix technology which includes thin film transistor, also called TFT. These transistors contain capacitors that enable individual pixels to retain the "actively" charge. Therefore active-matrix LCDs appear more efficient and more responsive than "passive-matrix display".

TYPES OF LCD
LCD's can be broadly divided into two categories.
I Field Effect Display (FED):
i) This type of field "Front" and "Back" polarizer's at right angles, or 90 degrees, contains Effect Displays with each other.
ii) They are placed in 90 ° with each other
iii) Without electricity excitation here, which comes to light, "front" polarizer becomes generally revolve within 90 ° fluid.

II. Dynamic Scattering Display (DSD)
i) In this dynamic scattering display, mainly TWO pieces of glasses are sandwiched with a very thin layer of LC material.
ii) A transparent conductive coating is found in the dark faces of the glass.
iii) Therefore, whenever the voltage is applied in it then the liquid crystal molecules themselves become realigned and begin to move randomly.
iv) This creates a "Turbulence" from which it disperse the light and ultimately appears "White Appearance" in it.