PURPOSE: To provide more relaxed manufacturing allowances, by disposing a plurality of linear thermionic cathodes between a back plate and an electron beam forming electrode so that three beams are formed of electrons emitted from one cathode and then converging them into one beam through a shadow mask.
CONSTITUTION: Between a back plate 23 and a beam forming plate 24 are disposed two linear thermionic cathodes 21 stretched in vertical direction with reference to the picture plate. Said beam forming electrode 24 is provided with through holes, which are disposed in the vertical direction with such intervals that will give sufficient resolution and in the horizontal direction in such number that three holes are corresponding to one cathode 21. And an image is displayed on the display plate 31 with a phosphor layer formed thereon by the electron beams landing thereon through focusing electrodes 26, 28 and a convergence electrode 27, deflecting plates 29, and a shadow mask 30. In this way, by converging three electron beams into one, the processing and assembling allowances of electrodes can be relaxed and power consumption by the cathodes can be reduced.
MIYAMA HIROSHI
TOMII KAORU
NISHIDA JIYUN
