Color cathode ray tube and method of manufacturing the same

A color cathode ray tube comprising:

• an envelope including a panel with a phosphor screen formed on an inner surface of the panel;
• an electron gun arranged in the envelope, for emitting electron beams toward the phosphor screen;
• a shadow mask which is provided facing the phosphor screen and has a number of apertures for selecting the electron beams, the apertures including a plurality of aperture columns arranged substantially in parallel to one another with intervals;
• and
• dielectric layers provided on a surface of the shadow mask on a side facing the electron gun and formed in stripes extending substantially in parallel with the aperture columns, the dielectric layers being positioned on both sides of each of the apertures to be charged by irradiation of the electron beams and to form an electron lens for acting the electron beams, wherein layout positions of the dielectric layers in relation to the aperture columns differ between a center part of the apertured region and a peripheral part of the apertured region in a direction of the long axis.

A color cathode ray tube comprising:

• an envelope including a panel with a phosphor screen formed on an inner surface of the panel;
• an electron gun arranged in the envelope, for emitting electron beams toward the phosphor screen;
• a shadow mask which is provided facing the phosphor screen and has a number of apertures for selecting the electron beams, the apertures including a plurality of aperture columns arranged substantially in parallel to one another with intervals;
• and
• dielectric layers provided on a surface of the shadow mask on a side facing the electron gun and formed in stripes extending substantially in parallel with the aperture columns, the dielectric layers being positioned on both sides of each of the apertures to be charged by irradiation of the electron beams and to form an electron lens for acting the electron beams, wherein the dielectric layers provided at a center part of the apertured region each have a width different from that of the dielectric layers provided at a peripheral part of the apertured region in the direction of the long axis.

A method of manufacturing a color cathode ray tube comprising an envelope including a panel with a phosphor screen formed on an inner surface of the panel;

• an electron gun arranged in the envelope, for emitting electron beams toward the phosphor screen;
• a shadow mask which is provided facing the phosphor screen and has a plurality of aperture columns provided in substantially parallel and each including a plurality of apertures arranged at a predetermined interval, to select the electron beams emitted from the electron gun;
• and stripe-shaped dielectric layers provided on a surface of the shadow mask on a side facing the electron gun, the dielectric layers being arranged on both sides of each of the aperture columns and extending substantially in parallel to the aperture columns to be charged by irradiation of the electron beams and to form an electron lens which acts on the electron beams, the method comprising:
• preparing a plate-like mask base material in which the apertures columns are formed;
• forming stripe-shaped insulating material layers on both sides of each of the apertures on a surface of the mask base material facing the electron gun;
• forming an overcoat layer, which prevents penetration of a lubricant oil, on the stripe-shaped insulating material layers;
• press-molding the mask base material on which the insulating material layers and the overcoat layer are formed, into a predetermined shape, thereby to form the shadow mask;
• and
• sintering the insulating material layers on the shaped shadow mask, to form the dielectric layers.