ELECTRON GUN STRUCTURE FOR IMAGE PICK-UP TUBE

摘要

PURPOSE:To remove leakage of emitting beams, so as to realize improvement of stability and reliability, by preparing an auxiliary electrode for trapping dispersing beams between the first bottom-fitted cylindrical electrode with a beam-restricting aperture and the second bottom-fitted cylindrical electrode located on the cathode side. CONSTITUTION:A cup-shaped auxiliary electrode 10 is prepared in the cylindrical opening part of the cup electrode 4 of a G2 electrode. The auxiliary electrode 10 has a central hole 10a, at its bottom, whose dimension is nearly similar to a central hole 4a at the bottom of a cup electrode 4. The central hole 10a is prepared in the posture in which it is on the axis similar to the central hole 4a and the beam restricting aperture 6a of a beam disc cup 6 and they are arranged in the order of 4a, 10a and 6a from the cathode side 2. The dispersing beams, which have so far leaked from a gap between the cup electrode 4 and the beam-disc cup 6, are trapped mostly by this auxiliary electrode 10.