Patent ID: 6288481
Filing Date: 2001-09-11
Classification: H01J

Abstract:
An in-line electron gun for a cathode ray tube, comprising:three cathodes arranged in a horizontal line to emit thermal electrons;a plurality of grid electrodes sequentially placed along a common axis transversing the horizontal line to focus and accelerate the thermal electrons into beam shapes, each of the grid electrodes having red, green and blue beam-guide holes, said grid electrodes comprising an outermost grid electrode spaced away from the three cathodes along the common axis; anda shield cup attached to the outermost grid electrode, the shield cup including a bottom having red, green and blue beam-guide holes having predetermined diameters and arranged in a row, and a side wall extending from a circumference of the bottom and having a substantially cylindrical shape, the shield cup comprising an induced electromotive force increasing unit for increasing the electromotive force near the red and blue beam-guide holes, and an induced electromotive force decreasing unit for decreasing the electromotive force near the green beam-guide hole,wherein the electromotive force increasing unit comprises a first burr formed along a circumference of the red beam-guide hole of the shield cup and a second burr formed along a circumference of the blue beam-guide hole of the shield cup, each of the burrs having a predetermined diameter and a predetermined height; andwherein the electromotive force decreasing unit comprises two opposing slits formed in the side wall and centered around the green beam-guide hole of the shield cup, each of the slits having a width less than or equal to the distance between the red and blue beam-guide holes and a predetermined depth.