Patent ID: 7834837

Claim:
An active matrix liquid crystal display (LCD) comprising: an LCD panel comprising: a plurality of gate lines that are parallel to each other and that each extend along a first direction; and a plurality of data lines that are parallel to each other and that each extend along a second direction orthogonal to the first direction; wherein the gate lines cross the data lines, thereby defining a plurality of pixel units, each pixel unit comprising: a liquid crystal capacitor comprising a pixel electrode and a common electrode; a thin film transistor (TFT) provided in the vicinity of a respective point of intersection of one of the gate lines and one of the data lines; and a storage capacitor connected in parallel with the liquid crystal capacitor; a gate driver connected to the gate lines; a data driver connected to the data lines; and a voltage compensating circuit including a memory circuit connected to the TFT, a comparator connected to the memory circuit, and a counter connected to the memory circuit and the gate driver; the counter controlling the memory circuit to detect a first voltage of a source electrode of one of the TFTs and store the first voltage of the source electrode of the TFT as a first signal data when the TFT turns on, and to detect a second voltage of a drain electrode of the TFT and store the second voltage of the source electrode of the TFT as a second signal data when the TFT turns off, the comparator comparing the first signal data and the second signal data, and then outputting a compensating voltage for compensating a kick-back voltage of the TFT if the first signal data is different from the second signal data.