LCD Active Matrix Display
A particular liquid crystal known as twisted nematics
is what makes LCD's possible.
It is a twisted crystal and is affected by electric current. When a current of a certain
voltage is applied, these crystals untwist themselves changing their structure. This is able to control the passage of light, a feature made possible by LCD's.
Active matrix LCD's make use of thin film transistors, the sends a charge to a particular
pixel, controlling the amount of light it lets through.