CART DISPLAY APPARATUS AND CUT-OFF ADJUSTING METHOD

摘要

PROBLEM TO BE SOLVED: To propose a cut-off adjusting method of CRT using a Hi-Gm tube and also to solve the problem that brightness of display screen with fluctuations in Gm voltage applied to a Gm electrode due to fluctuations in current fed into the Gm electrode and a G2 electrode. SOLUTION: A cut-off adjustment of the Hi-Gm tube is set in a manner that a Gm voltage of a Gm electrode power source 8 applied to a Gm electrode 5 becomes the same as a black level voltage applied to a cathode 2 to display a black level. A CRT display apparatus with the Hi-Gm tube is composed of a voltage detection circuit 14 to measure fluctuations in output voltages from the source 8 on the output side of the source 8, so that the source 8 can maintain the Gm voltage at constant with feedback from the circuit 14.