US4678964A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Color display tube
Assignee: US Philips Corp
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Filing: 1986-01-17
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Granted: 1987-07-07
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Expires: 2006-01-17
Abstract
Abstract A field correction element (30) is provided in the peripheral field of a focusing lens of an electron gun system of a color display tube to reduce the potential differences between the electrodes of the focusing lens necessary for horizontal and vertical focusing, respectively. The field correction element (30) consists of a plate (31) which extends substantially perpendicularly to the electron beams and has elongate or square apertures (32, 33, 34) through which the electron beams (6, 7, 8) pass. It is also possible to perform convergence corrections by means of such a field correction element.
Inventors
- 👤 Antonius H. P. M. Peels
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 10:52
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/46; H01J29/48; H01J29/50; H01J29/503; H01J2229/00; H01J2229/48; H01J2229/4844; H01J2229/4848; H01J2229/4858; H01J2229/4865; H01J2229/4875
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
203 words
In a color display tube comprising an evacuated envelope containing a luminescent screen and an electron gun system for producing a central electron beam and first and second outer electron beams lying in a single plane, said electron gun system including first and second spaced-apart cup-shaped focusing lens electrodes having respective first and second facing bottom plates, each plate including central and first and second outer apertures through which the corresponding electron beams pass, said electrodes cooperating to produce respective central and first and second outer focusing lenses for individually focusing the corresponding electron beams; the combination with at least one of said electrodes of correction means for correcting astigmatic focusing and misconvergence of the electron beams, said correction means comprising a correction plate disposed within the respective cup-shaped electrode and parallel to its apertured bottom plate, said correction plate including central and first and second outer apertures through which the respective electron beams pass, at least one of said apertures begin elongate and having an individual height and width selected relative to each other to correct for astigmatic focusing of the respective electron beam, said outer apertures being located relative to said central aperture to correct for misconvergence of the electron beams.
Claim 2
Dependent Claim
203 words
In a color display tube comprising an evacuated envelope containing a luminescent screen and an electron gun system for producing a central electron beam and first and second outer electron beams lying in a single plane, said electron gun system including first and second spaced-apart cup-shaped focusing lens electrodes having respective first and second facing bottom plates, each plate including central and first and second outer apertures through which the corresponding electron beams pass, said electrodes cooperating to produce respective central and first and second outer focusing lenses for individually focusing the corresponding electron beams; the combination with at least one of said electrodes of correction means for correcting astigmatic focusing and misconvergence of the electron beams, said correction means comprising a correction plate disposed within the respective cup-shaped electrode and parallel to its apertured bottom plate, said correction plate including central and first and second outer apertures through which the respective electron beams pass, at least one of said apertures begin elongate and having an individual height and width selected relative to each other to correct for astigmatic focusing of the respective electron beam, said outer apertures being located relative to said central aperture to correct for misconvergence of the electron beams.
Claim 3
Dependent Claim
41 words
A color display tube as in claim 1 where the apertures in the bottom plate of the cup-shaped electrode containing the correction plate are each surrounded by an inwardly-extending collar, and where the correction plate is positioned substantially against said collars.
Claim 4
Dependent Claim
24 words
A color display tube as in claim 1 or 2 where the at least one elongate aperture in the correction plate is substantially rectangular.
Claim 5
Dependent Claim
24 words
A color display tube as in claim 1 or 2 where the at least one elongate aperture in the correction plate is substantially oval.
Claim 6
Dependent Claim
32 words
A color display tube as in claim 1 or 2 where the correction plate forms a bottom part of a cup-shaped correction element which is disposed coaxially within the respective cup-shaped electrode.
Claim 7
Dependent Claim
33 words
A color display tube as in claim 5 where the electrode in which the correction plate is disposed is the last electrode of the electron gun system through which the electron beams pass.
References Cited (Backward Citations)
JPS5630239A
Cited
GB2085649A
Cited
US4406970A
Cited
JPS5864740A
Cited
US4581560A
Cited
US4535266A
Cited
US4584500A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-07-06 | 1991-01-05 | 1991-07-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-07-06 | 1995-01-05 | 1995-07-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-07-06 | 1999-01-05 | 1999-07-07 | $7700.00 | Window Closed / Lapsed |