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US 5,818,156 AGranted
Color cathode-ray tube
AssigneeHitachi, Ltd.
InventorMasayoshi Misono
Life of this patent
Estimating the term…
Abstract
A color cathode-ray tube which is provided with deflection error correcting electrodes for correction deflection errors in accordance with the deflected amounts of electron beams by forming a nonuniform electric field in a deflecting magnetic field and has a function of adjusting the deflected amounts of two side electron beams on both sides of a central electron beam of three electron beams from an electron gun and the deflected amount of the central electron beam. The focusing characteristic and resolution of the cathode ray tube are improved over the whole screen and over the whole current ranges of the electron beams without supplying any dynamic focusing voltage. The coma aberration is reduced and the cathode-ray tube can use a low-cost deflection yoke.
Claims17
A color cathode-ray tube comprising:
- an electron gun including cathodes for forming three electron beams in line including a central electron beam and two side electron beams, electrodes forming a main lens for shaping said electron beams, and a shield electrode arranged neighboring the electrodes forming the main lens along the tubular axis to protect said shaped electron beams from the external environment;
- deflection yokes generating a deflecting magnetic field to deflect said electron beams in the in-line direction and in a direction at right angles with the in-line direction;
- and
- a fluorescent screen which emits light when irradiated with said deflected electron beams to form a picture;
- wherein the shield electrode of said electron gun is arranged in the region of the deflecting magnetic field of said deflecting yokes, deflection error correction electrodes are provided so as to extend from a bottom of said shield electrode toward said fluorescent screen, said bottom of said shield electrode being disposed on a side of said cathodes and having at least one aperture through which said three electron beams pass, said deflection error correction electrodes forming a nonuniform electric field to change the diameter of the beams depending upon the amount of deflecting said electrons beams;
- and
- said deflection error correction electrodes function to change the amount of deflection individually for the central electron beam and for the side electron beams.
4 more elements
A color cathode-ray tube comprising:
- an electron gun including cathodes for forming three electron beams in line including a central electron beam and two side electron beams, electrodes forming a main lens for shaping said electron beams, and a shield electrode arranged neighboring the electrodes forming the main lens along the tubular axis to protect said shaped electron beams from the external environment;
- deflection yokes generating a deflecting magnetic field to deflect said electron beams in the in-line direction and in a direction at right angles with the in-line direction;
- and
- a fluorescent screen which emits light when irradiated with said deflected electron beams to form a picture;
- wherein the shield electrode of said electron gun is arranged in the region of the deflecting magnetic field of said deflecting yokes, a common single aperture is formed in a bottom of said shield electrode which is disposed on a side of said cathodes to permit passage of said three electron beams, deflection error correction electrodes are provided to form a nonuniform electric field on a side closer to said fluorescent screen than said single aperture in order to change the diameter of the beams depending upon the amount of deflecting said electrons beams;
- and
- said deflection error correction electrodes function to change the amount of deflection individually for the central electron beam and for the side electron beams.
4 more elements
A color cathode-ray tube comprising:
- an electron gun including cathodes for forming three electron beams in line including a central electron beam and two side electron beams, electrodes forming a main lens for shaping said electron beams, and a shield electrode arranged neighboring the electrodes forming the main lens along the tubular axis to protect said shaped electron beams from the external environment;
- deflection yokes having a coil and a core and generating a deflecting magnetic field to deflect said electron beams in the in-line direction and in a direction at right angles with the in-line direction;
- and
- a fluorescent screen which emits light when irradiated with said deflected electron beams to form a picture;
- wherein deflection error correction electrodes are provided to form a nonuniform electric field on a side closer to said fluorescent screen than to at least one aperture formed in a bottom of said shield electrode which is disposed on a side of said cathodes and through which said three electron beams pass, in order to change the diameter of the beams depending upon the amount of deflecting said electron beams, and a distance in a direction of said tubular axis is set to be not longer than 40 mm from an end of the core of said deflecting yoke which is disposed on the side of the cathodes to an end of said deflection error correction electrodes which is disposed on the side of the fluorescent screen;
- and
- said deflection error correction electrodes function to change the amount of deflection individually for the central electron beam and for the side electron beams.
4 more elements
Dependencies are inferred from the claim text.