Sony Corporation

Yoshifumi Nakayama

Yukinobu Iguchi

Masahiro Kikuchi

Yutaka Ota

Masanori Ando

Koji Ichida

Yuzuru Watanabe

Kouji Hasegawa

Youichi Ohshige

Hiromu Inoue

An electron gun for a color CRT has three cathodes disposed in parallel to each other, first to fifth grid electrodes and a convergence deflector. The electron gun is additionally provided with a tetrode magnetic field generator including a pair of permanent magnets having an astigmatic effect of the central beam of the electron gun on the cathode side of the convergence deflector. An astigmatism eliminator is provided to cancel astigmatic aberration of the side beams of the electron gun near the position where the electron beams are converged. The astigmatism eliminator is composed of a fifth grid electrode whose entrance has an electron beam passing hole of nearly elliptic shape.

Electron gun for color cathode-ray tube

A cathode-ray tube has an electron gun sealed in a neck in confronting relationship to the phosphor screen. The electron gun comprises a cathode assembly for emitting three electron beams, a main lens region for passing the electron beams therethrough, the main lens means including a high-voltage electrode or grid closer to the phosphor screen, and an assembly of electrostatic deflection plates, positioned closer to the phosphor screen than the high-voltage electrode, for converging the electron beams as one spot on the phosphor screen. An electrostatic convergence electrode assembly is disposed between the high-voltage electrode and the deflection plates. The electrostatic convergence electrode assembly may comprise three or two juxtaposed flat electrodes having electron beam passage holes. The voltages applied to the high-voltage electrode and the deflection plates are also applied selectively to the three or two electrodes of the electrostatic convergence electrode assembly for applying an astigmatic effect equally to the electron beams.

Cathode-ray tube with electrostatic convergence electrode assembly

An electron gun arrangement for color cathode-ray tubes comprising three cathodes for emitting electron beams, for example, for red, green and blue, and a main electron lens comprising three front electron lenses corresponding to the cathodes, respectively, and a back electron lens common to all the cathodes. Each front electron lens is formed with an aperture smaller than that of the back electron lens and is mounted so as to meet Fraunhofer conditions so that aberration is reduced. Electron beam transmitting apertures are formed in the grids forming the front electron lenses, respectively, with the respective center axes thereof parallel to each other, which makes it easy to manufacture the electron gun arrangement and enables accurate machining during manufacturing.

Electron gun for multigun cathode ray tube

An electron gun employed in a color cathode ray tube, or the like, adapted, when electron beams are deflected in a convergence free deflecting magnetic field, to achieve optimal focused conditions for both the electron beam landing at the center and that landing at the corners of a screen by making, within a principal converging region for converging the electron beams, the converging angle in the vertical direction smaller than that in the horizontal direction and by forming, within an object point forming region, the object point in the vertical direction at a further position than where the object point in the horizontal direction is formed.

Growing community of inventors

Kanagawa, Japan

Yoshifumi Nakayama