Disclosed is a video display an auto-convergence error in a projection
television receiver (TV) capable of preventing generation of an error
when an auto-convergence is performed. The apparatus includes a screen
for displaying an image signal, first to eighth sensing units having
first and second optical sensors for sensing a pattern displayed on the
screen, first and second amplifying units for receiving and amplifying
sensed values sensed by the first to fourth sensing units and the fifth
to eighth sensing units with predetermined multiple amplification
factors, first and second comparators for receiving and comparing
amplified values outputted from the first and second amplifying units, an
inverter for inverting output values of the first and second comparators,
an operation unit for AND-gating the outputs of the amplifying units and
outputs of the inverter, and a microcomputer for receiving an output of
the operation unit, judging a degree of convergence correction, and
outputting a corresponding control signal.