US3881136A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cathode ray tube comprising a non-rotationally symmetrical element
Assignee: US Philips Corp
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Filing: 1973-03-12
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Granted: 1975-04-29
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Expires: 1993-03-12
Abstract
Abstract In a cathode ray tube comprising a non-rotationally symmetrical electron-optical element, the image ratio of the main lens is adapted to the degree of astigmatism of the electron beam such that an electron spot having a predetermined axial ratio is produced on a target. Such a cathode ray tube is notably an index colour television tube.
Inventors
- 👤 Edial Francois Scheele
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 15:31
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/46; H01J29/48; H01J29/488; H01J29/56; H01J29/566
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
115 words
A cathode ray tube comprising an image screen and an electron gun containing a cathode, a control grid, an acceleration anode, a non-rotationally symmetrical electron-optical element, a main lens for the formation on an image plane of a target of an electron beam to be emitted by the cathode and an apertured diaphragm plate disposed at said main lens, said non-rotationally symmetrical element producing an emissive cathode surface having an ovall contour and an astigmatic electron beam, the position of the main lens being adapted to the degree of astigmatism of the beam such that an image of the electron beam in the image plane constitutes an accurately defined target having a predetermined axial ratio.
Claim 2
Dependent Claim
115 words
A cathode ray tube comprising an image screen and an electron gun containing a cathode, a control grid, an acceleration anode, a non-rotationally symmetrical electron-optical element, a main lens for the formation on an image plane of a target of an electron beam to be emitted by the cathode and an apertured diaphragm plate disposed at said main lens, said non-rotationally symmetrical element producing an emissive cathode surface having an ovall contour and an astigmatic electron beam, the position of the main lens being adapted to the degree of astigmatism of the beam such that an image of the electron beam in the image plane constitutes an accurately defined target having a predetermined axial ratio.
Claim 3
Dependent Claim
25 words
A cathode ray tube as in claim 1, wherein said non-rotationally symmetrical electron-optical element consists of a control grid aperture having a non-rotationally symmetrical limitation.
Claim 4
Dependent Claim
28 words
A cathode ray tube as in claim 2, wherein said grid aperture has a smaller surface area than an ellipse having substantially the same axial ratio and width.
Claim 5
Dependent Claim
18 words
A cathode ray tube as in claim 1, wherein said grid aperture has the configuration of an ellipse.
Claim 6
Dependent Claim
18 words
A cathode ray tube as in claim 1, wherein said non-rotationally symmetrical element is bounded by straight lines.
Claim 7
Dependent Claim
16 words
A cathode ray tube as in claim 1, further comprising a second non-rotationally symmetrical electron-optical element.
Claim 8
Dependent Claim
36 words
A cathode ray tube as in claim 6, wherein said second non-rotationally symmetrical element forms the aperture in a first anode of said electron gun, said two elements being cross-wise arranged with respect to each other.
Claim 9
Dependent Claim
51 words
A cathode ray tube as in claim 7, wherein both non-rotationally symmetrical apertures individually have the shape of a diamond, the length of a rectangular center part of the first said aperture being at the most equal to the width of a corresponding rectangular center part in the second said aperture.
Claim 10
Dependent Claim
19 words
A cathode ray tube as in claim 1, where said cathode ray tube is an index color television tube.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-28 | 1978-10-28 | 1979-04-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-28 | 1982-10-28 | 1983-04-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-28 | 1986-10-28 | 1987-04-29 | $7700.00 | Window Closed / Lapsed |