An active matrix display device uses an amorphous silicon drive transistor
for driving a current through an LED display element. First and second
capacitors are connected in series between the gate and source of the
drive transistor, with a data input to the pixel provided to the junction
between the first and second capacitors. The second capacitor is charged
to a pixel data voltage, and a drive transistor threshold voltage is
stored on the first capacitor. This pixel arrangement enables a threshold
voltage to be stored on the first capacitor, and this can be done each
time the pixel is addressed, thereby compensating for age-related changes
in the threshold voltage.