US Patent 7268478 Electron gun assembly and cathode ray tube with the same

An electron gun assembly for a cathode ray tube where the distortion of the electron beam that ordinarily occurs at the periphery of the screen is reduced. The electron gun assembly includes a cathode for emitting electrons, and a plurality of grid electrodes having a control electrode facing the cathode. The grid electrodes sequentially follow the cathode to focus and accelerate the electrons emitted from the cathode. The control electrode has a beam passage hole with a horizontal length H, and a vertical length V being larger than the horizontal length H. The ratio of the vertical to horizontal lengths satisfies the following condition: 1.03≦V/H≦1.63.