Electron gun with auxilliary anode nearer to grid than to normal anode

Claim 1

A cathode ray tube in which the improvement comprises an electron gun structure including: a cathode for emitting an electron beam, an anode electrode supported in alignment with said cathode having an anode aperture through which at least a portion of said beam passes, a grid electrode having a grid aperture therethrough supported between said anode and said cathode in axial alignment therewith for passage of said electron beam, said grid electrode having an annular shoulder portion on the side thereof opposite that facing the cathode, the shoulder portion having a substantially cylindrical inner aperture spaced from said grid aperture by a distance several times the diameter of said grid aperture, said inner aperture being substantially coaxial with the path of said electron beam, said anode aperture having a diameter of the same order of magnitude as said grid aperture, the diameter of said anode aperture being smaller than the diameter of said inner aperture of said shoulder, and an intermediate anode electrode supported next adjacent said grid electrode and the shoulder thereof between said grid electrode and said anode electrode in closer spaced relation to said grid electrode than to said anode electrode, said intermediate anode electrode having a large aperture therethrough in axial alignment with the aforementioned grid and anode apertures, the diameter of said large aperture being in the range of 1.25 to approximately 1.5 times larger than the inside diameter of the inner aperture of said annular shoulder portion while also being larger than the anode aperture.