Abstract: An electron gun for a color CRT includes a main focusing lens unit that focuses the electron beams generated by a triode unit. The main focusing lens unit includes a first and a second electrostatic screen grid having three electron beam through holes linearly-arranged for passing three electron beams, two of the holes being external and an oval shaped hole that passes all three electron beams. The oval shaped holes being spaced a distance, d1 and d2, respectively, from the through holes. Furthermore, the first grid external holes have an external distance HL1 and an internal distance HR1 and the second grid external holes have an external distance HL2 and an internal distance HR2; and wherein HL1 is greater than HR1, HL2 is greater than HR2, d1 is greater than d2, HL2 is greater than HL1, and HL2+HR2 is greater than HL1+HR1.

Abstract: An electron gun for a CRT includes a pair of bead glasses separated from and parallel to each other, supporting electrodes of the electron gun. An electrode has electron beam passing holes and at least one electrode support embedded in each bead glass. The electrode support includes at least two embedding protrusions embedded in the bead glass. One of the protrusions is longer than the other protrusion. The structure of the electrode support is improved so cracks in a bead glass during a beading process do not occur and twisting in a gap between the bead glass and an electrode support is minimized. There is no gap between the bead glass and the electrode, so leakage current does not flow between the electrodes, improving the lifetime of electrical features of the electron gun.

Abstract: A mount assembly (20) for a lamp has a glass stem (22) having a first portion (24) that is tubular and has an outside diameter D2 and a second portion (26) formed as a pinch seal with at least one dimension greater than D2. A substantial C-shaped clip (10) is mounted upon the first portion (24). The C-shaped clip (10) has a given height H and an inside diameter D that is smaller than the outside diameter D2 whereby the clip (10) frictionally engages the first portion (24). A pair of substantially oppositely located cutouts (12, 14) is formed in the clip (10), each providing an extending flap (16, 18) projecting away from the clip (10). The clip is positioned on the first portion (24) such that at least a part of said second portion (26) is contained within the cutouts (12, 14). A first frame member (28) is affixed to the flap (16) and a second frame member (28) is affixed to the flap (18). This assembly accurate supports the structure and prevents rotation of the mount assembly.

Abstract: A vertical electrode plate having three openings formed in-line through which three electron beams pass respectively is provided only inside a focusing electrode out of the focusing electrode and a final accelerating electrode. A horizontal electrode plate that is substantially parallel to an in-line plane extending toward the focusing electrode is formed at least one of above and below openings at the bottom of a shielding cup, only inside the final accelerating electrode. By setting the height h of the horizontal electrode plate optimally, it is possible to correct a horizontally-elongated distortion of a spot shape in edge portions of a screen, caused by a self-convergence magnetic field of a deflecting device. In this manner, a color display tube that achieves an image display with a high resolution can be provided.

Abstract: A cathode ray tube and a plural beam electron gun therefor include a main lens that comprises a tubular focus grid G5 and a conductive coating on the inner surface of the tube neck. The neck coating extends from the region of focus grid G5 towards the faceplate of the cathode ray tube. Preferably, the exit of the focus grid G5 is non-planar and is curved or undulated and focus grid G5 includes an aperture plate intermediate its entrance and exit. The aperture plate preferably has an elliptical center beam opening and connected-semi-elliptical outer-beam openings, to better converge and focus the outer and center electron beams. Also preferably, the focus grid G5 is centrally located in the tube neck and at least partly surrounded by the conductive neck coating.

Abstract: A color cathode ray tube includes an evacuated envelope formed of a panel portion having a phosphor screen, a neck portion and a funnel portion connecting the panel portion and the neck portion, and an in-line electron gun housed in the neck portion. The in-line electron gun includes a main lens and an electrostatic quadrupole lens. The focus electrode of the electron gun has a single opening at one end thereof for passing the three electron beams and opposes an anode to form a main lens therebetween. The single opening has a diameter larger in a horizontal direction than a diameter thereof in a vertical direction. A distance from the main lens to the phosphor screen is not larger than 300 mm, an outer diameter T of the neck portion housing the in-line electron gun satisfies the following inequality: 23.2 mm.ltoreq.T.ltoreq.25.

Abstract: This invention provides a process for forming a phosphor screen of a monochrome cathode ray tube (projection tube) which has an improved luminance remaining property. The phosphor particles are settled on an inner surface of a glass bulb with a binder of SiO.sub.2 to form a phosphor layer, in which the amount of SiO.sub.2 is reduced by rinsing with a water-based liquid like deionized water and a PVA solution before forming an organic layer on the phosphor layer. The phosphor screen has an improved luminance remaining property that is close to that of a direct viewing color cathode ray tube, without lowering the screen quality.

Abstract: A multicolor cathode-ray tube for use as a light source in a giant display system such as a display board for a sports stadium. The cathode-ray tube includes a plurality of electron guns and respective fluorescent screens, the latter receiving the beam from a corresponding electron gun. Each of the screens is slanted towards the longitudinal axis of the tube. The screens may be either flat or curved.