The present invention relates to a color cathode ray tube and, more particularly, to a color cathode ray tube of a multineck structure, which has a multiple number of necks and electron gun assemblies accommodated in the respective necks, and the screen of which is defined by a plurality of continuous display segment regions, each emitting light upon landing of electron beams from a corresponding one of the electron guns.
Color cathode ray tubes have received a great deal of attention as high-quality broadcast image display devices or computer terminal high-resolution graphic display devices. For these applications, increased resolution has been an issue. High resolution in a color cathode ray tube can be achieved by minimizing an electron beam spot on its phosphor screen. However, in order to minimize the electron beam spot, the electrode structure of the electron gun assembly must be improved, or the electron gun assembly itself must be elongated and enlarged to increase its diameter. However, large electron gun assemblies cannot provide a sufficiently small electron beam spot for the following reason. The larger the size of the color cathode ray tube becomes, the longer the distance between the electron gun assembly and the phosphor screen becomes. In addition, the electron lens thereof has an undesirable large magnification. In order to achieve high resolution of a large cathode ray tube, it is important to decrease the distance between the electron gun assembly and the phosphor screen. For this purpose, the tube can be constituted by a wide-angle deflection tube. However, in such a tube, the magnification at the central portion of the screen differs from that at the peripheral portions thereof.
In order to solve the above problem, Japanese Patent Disclosure (Kokai) No. 48-90428 describes a multi-tube structure display device having a plurality of small or medium size cathode ray tubes, arrayed in the horizontal or vertical direction to display an image on a large screen with high resolution.
A conventional display device of the multi-tube structure can be effectively used outdoors to display an image on a very large screen divided into blocks. However, the display device is not suitable for a medium size screen, i.e., about 40", since the joints of the divided blocks of the screen stand out, presenting a poor image. In particular, when this device is used as a computer-aided design graphic display terminal, the presence of joints becomes a decisive shortcoming.