US4992697A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Picture display device with magnetizable core means comprising compensation coils
Assignee: US Philips Corp
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Filing: 1989-01-25
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Granted: 1991-02-12
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Expires: 2009-01-25
Abstract
Abstract Deflection unit mounted around a display tube for deflecting electron beams across the display screen includes a line deflection coil and a field deflection coil. A compensation coil system for generating a magnetic compensation field oppositely directed to the line frequency radiation field in a space in front of the display screen includes core means of a magnetizable material positioned between the display screen and the deflection unit in a plane parallel to the display screen and two diametrically arranged coils each having at least one turn.
Inventors
- 👤 Johannes Penninga
- 👤 Albertus A. S. Sluyterman
- 👤 Bernardus H. J. Dekkers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 22:48
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/003; H01J2229/00; H01J2229/0007; H01J2229/0015
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
211 words
A picture display device having a display tube whose rear portion consists of a cylindrical neck accommodating a device for generating electron beams and whose front portion is funnel-shaped, the widest portion being present on the front side and comprising a phosphor display screen, said display device also comprising an electro-magnetic deflection unit mounted around a part of the display tube for deflecting electron beams across the display screen, said unit comprising a line deflection coil having two line deflection coil halves arranged on either side of a plane of symmetry and a field deflection coil, and a compensation coil system for generating a magnetic compensation field which is oppositely directed to the line frequency radiation field in a space in front of the display screen, characterized in that the compensation coil system includes a core means of magnetizable material which is positioned between the display screen and the deflection unit in a plane parallel to the display screen and which has two diametrically arranged coils each comprising at east one turn, the distance between the compensation coil system and the deflection unit being chosen so that, in operation, the compensation coil system produces a deflection of the electron beams which is insignificant compared to that produced by the deflection unit.
Claim 2
Dependent Claim
211 words
A picture display device having a display tube whose rear portion consists of a cylindrical neck accommodating a device for generating electron beams and whose front portion is funnel-shaped, the widest portion being present on the front side and comprising a phosphor display screen, said display device also comprising an electro-magnetic deflection unit mounted around a part of the display tube for deflecting electron beams across the display screen, said unit comprising a line deflection coil having two line deflection coil halves arranged on either side of a plane of symmetry and a field deflection coil, and a compensation coil system for generating a magnetic compensation field which is oppositely directed to the line frequency radiation field in a space in front of the display screen, characterized in that the compensation coil system includes a core means of magnetizable material which is positioned between the display screen and the deflection unit in a plane parallel to the display screen and which has two diametrically arranged coils each comprising at east one turn, the distance between the compensation coil system and the deflection unit being chosen so that, in operation, the compensation coil system produces a deflection of the electron beams which is insignificant compared to that produced by the deflection unit.
Claim 3
Dependent Claim
34 words
A device as claimed in claim 1, characterized in that each of the two coils is of the toroidally wound type arranged proximate to locations where said plane of symmetry intersects the display tube.
Claim 4
Dependent Claim
34 words
A device as claimed in claim 1, characterized in that each of the two coils is of the saddle type arranged on a core portion and on either side of said plane of symmetry.
Claim 5
Dependent Claim
41 words
A device as claimed in claim 1, characterized in that the core means comprises one single closed annular core which is arranged parallel to the display screen and surrounds the display tube at a position in front of the deflection unit.
Claim 6
Dependent Claim
39 words
A device as claimed in claim 2, characterized in that the core means comprises two core portions intersecting the plane of symmetry of the line deflection coil and in that each coil is separately wound around a core portion.
Claim 7
Dependent Claim
49 words
A device as claimed in claim 5, characterized in that the core portions are arranged on either side of the funnel-shaped portion of the display tube, symmetrically with respect to the plane through the tube axis which is perpendicular to the plane of symmetry of the line deflection coil.
Claim 8
Dependent Claim
16 words
A device as claimed in claim 6, characterized in that the core portions are annular segments.
Claim 9
Dependent Claim
15 words
A device as claimed in claim 6, characterized in that the core portions are rod-shaped.
Claim 10
Dependent Claim
34 words
A device as claimed in claim 8, characterized in that the core portions are provided with coils having a coil-winding pattern comprising an upwardly going winding and a downwardly going winding crossing each other.
Claim 11
Dependent Claim
55 words
A device as claimed in claim 8, characterized in that the core portions are provided with coils having turns whose turn planes are at least substantially parallel to the plane of symmetry of the line deflection coil, said turns being interconnected by means of wire pieces extending parallel to the axis of the core portions.
Claim 12
Dependent Claim
45 words
A device as claimed in claim 4, characterized in that the projection of the annular core on the plane of symmetry of the line deflection coil has a dimension parallel to the display screen which is larger than the dimension perpendicular to the display screen.
Claim 13
Dependent Claim
31 words
A device as claimed in claim 1, characterized in that the core means is located in a plane at least substantially comprising an imaginary radiation centre of the line deflection coil.
Claim 14
Dependent Claim
50 words
A device as claimed in claim 1, characterized in that the coils of the compensation coil system have the same winding direction and, in operation, are adapted to be connected to a line frequency current source in such a way that the fields which they generate have the same direction.
Claim 15
Dependent Claim
29 words
A device as claimed in claim 8, characterized in that permanent magnets are arranged at opposite ends of the rod-shaped core portions for the purpose of landing error correction.
Claim 16
Dependent Claim
41 words
A device as claimed in claim 8, characterized in that a diode configuration is electrically connected to the coils arranged on the rod-shaped core portions, such that in operation mainly that coil is energized which is remotest from the deflected beams.
References Cited (Backward Citations)
US2921226A
Cited
US3424942A
Cited
EP0220777A1
Cited
JPS63944A
Cited
US4853588A
Cited
JPS6376245A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-02-11 | 1994-08-13 | 1995-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-02-11 | 1998-08-13 | 1999-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-02-11 | 2002-08-13 | 2003-02-12 | $7700.00 | Window Closed / Lapsed |