A projection television and a convergence control method thereof are provided.
The projection television, which magnifies images displayed on cathode ray tubes
(CRTs) for the colors red, green, and blue using lenses and projects the magnified
images onto a screen, includes a convergence control apparatus capable of adjusting
the convergence while an input image signal is displayed, the convergence control
apparatus including: an image signal decoder which processes the input image signal
to generate a data signal, horizontal and vertical synchronous signals, and a start
signal indicating the start of either the horizontal or vertical synchronous signal;
a convergence control unit which normally projects an image signal output from
the image signal decoder onto the screen and performs convergence control using
a predetermined region of the screen displaced from a visible region of the screen
according to a convergence control command; and a main microcomputer which inputs
the convergence control command to the convergence control unit when the start
signal is input from the image signal decoder, stops the convergence control when
a completion signal is input from the convergence control unit, and performs a
control operation to continuously display the image signal during the convergence control.