Introduction
The most common type of LCD display contains, besides the polarizing sheets and cells of liquid crystal, a matrix of TFTs to make a TFT-LCD. These devices store the electrical state of each pixel on the display while all the other pixels are being updated. This method provides a much brighter, sharper display than a passive matrix of the same size. An important specification for these displays is their viewing-angle.
Thin-film transistors are usually used for constructing an active matrix so that the two terms are often interchanged, even though a thin film transistor is just one component in an active matrix and some active-matrix designs have used other components such as diodes. Whereas a passive matrix display uses a simple conductive grid to deliver current to the liquid crystals in the target area, an active-matrix display uses a grid of transistors and capacitors with the ability to hold a charge for a limited period of time. Because of the switching action of transistors, only the desired pixel receives a charge, and the pixel acts as a capacitor to hold the charge until the next refresh cycle, improving image quality over a passive matrix.
Read more about this topic: Active-matrix Liquid Crystal Display
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