TFT LCD, or Thin-film-transistor Liquid-crystal display, is a type of LCD that uses the TFT technology to improve contrast and addressability. LCD is the most common type of display used today. In fact, you run into an abundance of LCD’s every day, such as the temperature control display in your home, your computer screen at the office, on the subway, in your car, at the hospital – countless of screens.
A common LCD display is built with three key components: glass, polarizing plates, and most importantly, liquid crystal. The liquid-crystal is packed in between two sheets of glass and by applying voltage to the glass, you can control the liquid crystal molecules by changing their direction. This ultimately affects the optical characteristics of the display. By adding polarizing plates to the equation, we can control the quantity of light transmission which gives us the ability to show graphic elements on a display.
So why do we use a TFT? A TFT acts as a kind of light switch and aids in controlling all the millions of sub-pixels that exists in an LCD. To activate all the sub-pixels a TFT is needed in each sub-pixel, meaning that if you have a full-HD resolution (1080x1920x3) you end up with more than six million pixels, and you will need the same amount of TFTs. LCD displays need a backlight to show the graphics on the display (think of how old Casio watches are lit up), and without a TFT you won’t get the same kind of high contrast and bright colors that we are used to seeing on our screens today.
To conclude, using a TFT LCD gives you better control of what exactly is shown in each pixel on the screen. This ultimately gives a higher contrast, better brightness, stronger sense of layering and brighter colors.