Color picture tube including an electron gun in a coated tube neck

An electron gun for producing at least three beams of electrons at an exit thereof comprising:

• at least three electron sources for producing the at least three beams of electrons;
• a pre-focus lens for at least partly focusing each of the beams of electrons;
• a main lens of the electron gun including a hollow electrode at the exit of the electron gun for focusing and converging the at least three beams of electrons, said hollow electrode having an entrance and having an exit opening at the exit of the electron gun, and an aperture plate intermediate the entrance and the exit opening, wherein the aperture plate has at least an elliptical center opening and two outer openings defined by two connected semi-ellipses through which respective ones of the at least three electron beams pass.

An in-line electron gun for producing three beams of electrons at an exit thereof comprising:

• at least three electron sources disposed in-line for producing three substantially co-planar beams of electrons;
• a pre-focus lens for at least partly focusing each of the beams of electrons;
• a main lens including a focus grid including a hollow tube having an entrance, a substantially open exit opening at the exit of the electron gun and a non-uniform dimension in the direction of electron travel therethrough, thereby to define a non-planar exit opening at the exit of the electron gun, and having an aperture plate intermediate the entrance and the open exit opening, wherein said aperture plate has at least an elliptical center opening and two outer openings defined by two connected serni-ellipses through which respective ones of the at least three electron beams pass.

In a cathode ray tube including a neck, a funnel and a faceplate having an anode thereon for biasing at a positive anode potential, and having an electron gun in the neck thereof that produces at an exit of the electron gun at least three beams of electrons directed toward the faceplate, the improvement comprising:

• a main lens of the electron gun including two spaced-apart electrodes for focusing and converging the at least three beams of electrons, a first of said electrodes having a non-uniform dimension in the direction of electron travel therethrough thereby to define a substantially open non-planar exit opening at the exit of the electron gun, and a second of said electrodes including a conductive coating on an inner surface of said tube neck, wherein the first electrode is biased at a different positive potential than is the conductive coating.

In a cathode ray tube including a neck, a funnel and a faceplate and having an electron gun in the neck thereof that produces at an exit of the electron gun at least three beams of electrons directed toward the faceplate, the improvement comprising:

• a main lens of the electron gun including two spaced-apart electrodes for focusing and converging the at least three beams of electrons, a first of said electrodes having a substantially open exit opening at the exit of the electron gun and an aperture plate having at least an elliptical center opening and two outer openings each defined by two connected semi-ellipses through which respective ones of the at least three electron beams pass, and a second of said electrodes including a conductive coating on an inner surface of said tube neck, wherein the first electrode is biased at a diferent potential than is the conductive coating.