Patent ID: 6307314
Filing Date: 2001-10-23
Classification: H01J

Abstract:
A cathode ray tube apparatus comprising:a vacuum envelope including a faceplate having on the inner surface thereof a rectangular phosphor screen having an aspect ratio M:N between the length along the horizontal axis perpendicular to the tube axis and the length along the vertical axis perpendicular to the tube axis and the horizontal axis, a cylindrical neck portion having an electron gun assembly built therein for emitting electron beams in the direction along the tube axis, a funnel portion for connecting said faceplate and said neck portion, and a yoke portion of which a section perpendicular to the tube axis on the neck portion side of the fimnel portion changes in shape from a circle of the same diameter as the neck portion to a non-circle having a maximum diameter in other than the directions along the horizontal axis and the vertical axis;wherein said yoke portion has at least a section perpendicular to said tube axis expressed as(M+N)/(2*(M.sup.2 +N.sup.2).sup.1/2)<(SA+LA)/(2DA).ltoreq.0.86where SA is the outer diameter along the vertical axis, LA the outer diameter along the horizontal axis, and DA the maximum outer diameter; anda deflection yoke mounted on the outer surface of the vacuum envelope and extending from said neck portion to the yoke portion for forming a deflection magnetic field for deflecting the electron beams;wherein said yoke portion is a non-circle with at least a section perpendicular to the tube axis having a maximum outer diameter in a direction other than the vertical axis and the horizontal axis where the distance between said tube axis and the outer surface of said yoke portion is the outer diameter of the yoke portion;wherein said deflection yoke includes a cylindrical separator interposed between a horizontal deflection coil and a vertical deflection coil for forming said deflection magnetic field; andwherein the outer diameter of the separator is equal to the distance between the tube axis and the outer surface of said separator, at least a section of said separator perpendicular to said tube axis is a non-circle having a maximum outer diameter in other than the directions along the vertical axis and the horizontal axis; and said separator has at least a section perpendicular to said tube axis expressed as(M+N)/(2*(M.sup.2 +N.sup.2).sup.1/2)<(SS+LS)/(2DS).ltoreq.0.90where SS is the outer diameter along the vertical axis, LS the outer diameter along the horizontal axis, and DS the maximum outer diameter.