Patent ID: 7227593
Filing Date: 2007-06-05
Classification: H04N

Abstract:
1. An apparatus for preventing an auto-convergence error in a projection television receiver (TV) provided with a screen for displaying an image signal and first to eighth sensing units having first and second optical sensors for sensing a pattern displayed on the screen, the apparatus comprising: 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.