The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 05, 1985
Filed:
Sep. 28, 1981
Richard M Gorski, Chicago, IL (US);
Zenith Electronics Corporation, Glenview, IL (US);
Abstract
An ultra-short high-performance LoBi electron gun is disclosed for use in very short cathode ray tubes. The gun comprises lower end means having a cathode for developing an electron beam, at least one apertured plate grid electrode for forming the beam in conjunction with the cathode, and at least one apertured plate prefocusing electrode for developing a crossover in the beam in conjunction with the grid electrode. The gun also comprises a main focus lens means for receiving, focusing and accelerating the beam. The lens means includes cylindrical focusing electrode means for focusing a beam spot of minimum size on the screen. The spacing between the focusing electrode and the prefocusing electrode, and the relative difference in potential therebetween, is effective to develop a weak electrostatic field for forming a steeply expanding beam, while cylindrical accelerating electrode means provides for accelerating the beam. The ratio of the potentials on the accelerating electrode and the focusing electrode is greater than six to one for forming a relatively strong electrostatic field therebetween. The weak electrostatic field between the prefocusing electrode and the focusing electrode means is effective to produce the steeply expanding beam for optimum filling of the main focus lens means. The relatively strong electrostatic field between the focusing electrode means and the accelerating electrode means is effective to produce a finely focused electron beam notwithstanding the ultra-short length of the gun.