Electronic gun of colour cathode ray tube

Abstract

In an color CRT, an electron gun for the color CRT includes a triode unit for generating three electron beams and controlling and accelerating the generated electron beams; a main focusing lens unit that focuses the electron beams generated by the triode unit; a first electrostatic screen grid installed in the main focusing lens unit having three electron beam through holes linearly-arranged for passing the three electron beams and two of the holes are external holes, and the first grid having a first oval shaped hole that passes all three electron beams, the first oval shaped hole spaced a distance d1 from the through holes; and a second electrostatic screen grid installed in the main focusing lens unit having three electron beam through holes linearly-arranged for passing the three electron beams and two of the holes are external holes, and the second grid having a second oval shaped hole that passes all three electron beams, the second oval shaped hole spaced a distance d2 from the through holes; wherein 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.

Description

technical field [0001] The invention relates to a color cathode ray tube (CRT), in particular to an electron gun of the color cathode ray tube. Background technique [0002] Generally, a color cathode ray tube is a type of display used in televisions, oscilloscopes, observation radar, etc. An image is displayed on the front surface of the screen panel by controlling the electron beams from the electron gun according to the received image signal and by colliding with the phosphor coating formed behind the screen panel. [0003] figure 1 A schematic diagram of a common cathode ray tube is shown. The cathode ray tube includes a screen panel 102 as a front glass; a funnel tube 103 forming a vacuum rear glass by bonding with the screen panel; a fluorescent screen 104 coating the inner surface of the panel 102 with phosphor A coating is formed to emit light when the electron beam collides; an electron gun 106 is used to emit the electron beam 107 that collides with the phosphor...

AI Technical Summary

Problems solved by technology

However, when the electron beam 107 passes through the control grid 131 and the second focus grid 133b, the electron beam convergence of the first and second electrostatic shielding grids 134a, 134b having approximately the same shape and size decreases, thereby exceeding the adjustment range.

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