Driver circuit for active matrix display and method of operating same

摘要

A driver circuit for use with an active matrix display. The driver circuit has a shift register circuit of a redundant configuration and consists of a main circuit and a preliminary circuit. When the main circuit becomes defective, the operating circuit is automatically switched from the main circuit to the preliminary circuit without physically cutting the circuitry by a laser beam or the like. The driver circuit is composed of a main shift register circuit and a preliminary shift register circuit connected in parallel with the main shift register circuit. The output from the final stage of flip-flop circuit of the flip-flop circuits forming the main shift register circuit is compared with the output from a monitoring flip-flop circuit connected with the output of the final stage of flip-flop circuit. Thus, the output signals from the flip-flop circuits of the main shift register circuit are switched respectively to the output signals from the flip-flop circuits of the preliminary shift register circuit.