Patent ID: 6111350
Filing Date: 2000-08-29
Classification: H01J

Abstract:
A color cathode ray tube comprisingan evacuated envelope comprising a panel portion, a neck portion and a funnel portion for connecting said panel portion and said neck portion,a three-color phosphor screen formed on an inner surface of said panel portion,a shadow mask having a multiplicity of apertures therein and spaced from said phosphor screen,a three-beam in-line type electron gun housed in said neck portion,said three-beam in-line type electron gun including an electron beam generating section for generating three controlled electron beams and a main lens section for focusing said three electron beams on said three-color phosphor screen anda deflecting device mounted in a vicinity of a transition region between said funnel portion and said neck portion for scanning said three electron beams on said three-color phosphor screen,wherein said main lens section comprises a focus electrode and an anode facing said focus electrode,each of said focus electrode and said anode comprises an electrode having a single opening common for said three electron beams in an end thereof facing each other and a plate electrode disposed therein and for forming three beam apertures for passing said three electron beams respectively, and satisfies a following inequality:(A+566)/106>H-2.times.Swhere A is V1.times.V2.times.T,V1 is a vertical diameter of said single opening,V2 is a vertical diameter of a center one of said three beam apertures andT is an axial distance between said single opening and said plate electrode,H is a horizontal diameter of said single opening,S is P.times.L/Q,P is a horizontal center-to-center spacing between adjacent phosphor elements at a center of said three-color phosphor screen,Q is an axial spacing between said three-color phosphor screen and said shadow mask at the center of said three-color phosphor screen, andL is an axial distance between said shadow mask and said single opening in said focus electrode.