TEST PROCESS FOR REDUNDANT SHIFT REGISTERS

摘要

Display device with a plurality of selection lignes including redundant selection line scanners. Each scanner includes a plurality of equivalent stages provided with an input terminal and an output terminal. The stages and the selection lines are numbered in order and the stages with corresponding numbers are connected to the opposite ends of the selection lines with corresponding numbers by separate line segments. The stages in each scanner are cascaded by connecting the output terminal of each stage to the input terminal of the stage immediately following. The selection line scanners can operate independently providing of electrical power supplies and separate time signal generators. During the test, one of the scanners is made to appear as a high impedance in relation to the scanner being tested. The defective stages of a scanner are replaced by the correspondingly numbered stage of the other scanner by simply cutting the separate line segment of the defective stage.