(19)
(11) EP 0 085 238 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
17.07.1985 Bulletin 1985/29

(43) Date of publication A2:
10.08.1983 Bulletin 1983/32

(21) Application number: 82306565

(22) Date of filing: 09.12.1982
(84) Designated Contracting States:
CH DE FR GB IT LI NL SE

(30) Priority: 19.01.1982 US 340683

(71) Applicant: Hewlett-Packard Company
 ()

(72) Inventor:
  • Reed, Ronald G.
     ()

   


(54) Cathode ray tubes


(57) The horizontal and vertical deflection factors for a split anode beam penetration color CRT are compensated for changes and remain constant as trace color is varied. In an electro-statically deflected tube a correction lens (17) near an expansion mesh (21) and electrically connected to the split anode faceplate alters the radial velocities of electrons leaving the mesh such that their point of impact upon the faceplate is unaffected by changes in axial velocity induced to change trace color. In a magnetically deflected tube a correction lens (55) in the neck near the entrance to the deflection yoke is supplied with a voltage that varies in conjunction with that of the faceplate. The axial velocity of the electrons in the region of magnetic deflection is adjusted to produce amounts of deflection that remain constant despite changes in the faceplate voltage.






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