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US 4,972,519 AGranted
Vertical coma correction arrangement
AssigneeRCA Licensing Corporation
InventorMichael D. Grote
Life of this patent
Estimating the term…
Abstract
An assembly that includes four separate tabs is used for producing from a stray magnetic field flux, a pincushion shaped field in a portion of the neck of a cathode ray tube that is located at the rear of a deflection yoke for providing vertical convergence coma correction. Coils that are wound around the tabs form a quadrupole electromagnet that also provides dynamic convergence correction.
Claims14
A television display apparatus, comprising:
- a cathode ray tube for producing three in-line electron beams that travel through a neck of said cathode ray tube;
- a deflection yoke including a horizontal deflection winding, a vertical deflection winding and a magnetically permeable core encircling a longitudinal axis of said neck, and having a beam entrance region and a beam exit region, said deflection yoke producing a main magnetic flux inside said neck of said cathode ray tube that deflects said electron beams;
- a magnetically permeable assembly of a plurality of magnetically permeable field formers disposed around said neck in the vicinity of said beam entrance region for collecting a stray magnetic field flux produced by said deflection yoke and for producing from said collected flux a first correction magnetic field inside said neck, in said beam entrance region between corresponding ones of said field formers, that corrects a first electron beam landing error;
- and
- a correction coil arrangement magnetically coupled to said magnetically permeable assembly and responsive to a deflection synchronized current for producing a second correction magnetic field inside said neck, in said beam entrance region between corresponding ones of said field formers, that dynamically corrects a second electron beam landing error.
2 more elements
A television display apparatus, comprising:
- a cathode ray tube for producing three in-line electron beams that travel through a neck portion of said cathode ray tube;
- a deflection yoke including a horizontal deflection winding, a vertical deflection winding and a magnetically permeable core, forming an inner cavity that receives said neck portion of said cathode ray tube and having a beam entrance region and a beam exit region, for producing a main magnetic flux in said neck portion of said cathode ray tube that deflects said electron beams;
- and
- a plurality, greater than two, of magnetically permeable field formers disposed around said neck portion in the vicinity of said beam entrance region, each one being magnetically separated from the other ones, for collecting a stray magnetic field flux produced by said deflection yoke outside both said deflection yoke and said inner cavity to produce from said collected flux a magnetic field in said beam entrance region that provides convergence error correction, a given one of said field formers comprising a plate having a width dimension that is substantially larger than its corresponding thickness dimension.
1 more element
A television display apparatus, comprising:
- a cathode ray tube for producing three in-line electron beams that travel through a neck portion of said cathode ray tube;
- a deflection yoke including a horizontal deflection winding, a vertical deflection winding and a magnetically permeable core, encircling a longitudinal axis of said neck portion and having a beam entrance region and a beam exit region, for producing a main magnetic flux in said neck portion of said cathode ray tube that deflects said electron beams;
- and
- a plurality, greater than two, of magnetically permeable field formers disposed around said neck portion in the vicinity of said beam entrance region, each one being magnetically separated from the other ones and each comprising a plate having a width dimension that is substantially larger than its corresponding thickness dimension, for collecting a stray magnetic field flux produced by said deflection yoke and for producing from said collected flux a magnetic field in said beam entrance region between corresponding ones of said field formers that provides convergence correction such that, in the absence of said field formers, said collected stray magnetic field flux would otherwise have formed a closed-loop path outside said neck portion of said cathode ray tube.
1 more element
A television display apparatus, comprising:
- a cathode ray tube for producing three in-line electron beams that travel through a neck of said cathode ray tube;
- a deflection yoke including a horizontal deflection winding, a vertical deflection winding and a magnetically permeable core, forming an inner cavity that receives said neck portion of said cathode ray tube and having a beam entrance region and a beam exit region, for producing a main magnetic flux in said neck of said cathode ray tube that deflects said electron beams;
- a plurality of magnetically permeable field formers disposed around said neck in the vicinity of said beam entrance region for collecting a stray magnetic field flux produced by said deflection yoke outside both said deflection yoke and said inner cavity to produce from said collected flux a magnetic field in said beam entrance region that corrects vertical coma convergence error;
- and
- a correction coil magnetically coupled to a given one of said field formers and responsive to a vertical rate parabolic current for producing a correction magnetic field in said beam entrance region that provides dynamic convergence in a horizontal direction.
2 more elements
Dependencies are inferred from the claim text.