Patent US3728569A successfully refreshed from Google Patents.
US3728569A
Expired / Lapsed
US
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Cathode-ray tube
Assignee: US Philips Corp
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Filing: 1971-09-24
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Granted: 1973-04-17
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Expires: 1991-09-24
Abstract
Abstract A cathode-ray tube in which a number of electron beams are produced. The tube comprises a luminescent screen and, at a short distance therefrom, a color selection electrode. The electron beams are converged by means of a magnetic convergence device. The part of the convergence device present inside the tube comprises for each electron beam a pair of plate-shaped pole shoes. Each pole shoe is provided in a cylindrical part of the convergence device through an axial gap. The cylindrical part of the convergence device furthermore comprises gaps in such manner that it holds for each axial gap that no closed electric connection exists around a single gap. As a result of this the occurrence of circulating currents around the axial gaps is counteracted.
Inventors
- 👤 J Gerritsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 10:14
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/46; H01J29/70; H01J29/701; H01J29/707
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
168 words
A cathode ray tube comprising: a. an evacuated envelope; b. electron gun means for producing a plurality of electron beams; c. a luminescent screen and a color selection electrode located on the gun side of said screen; d. means for converging said electron beams in the plane of said color selection electrode, said converging means comprising a tubular member including a peripheral portion and a plurality of pairs of pole shoes employed for dynamically converging said electron beams and further comprising means for screening each one of said pairs of pole shoes from others of said pairs, said peripheral portion comprising spaced axial gaps through respective ones of which said pole shoes extend into said tubular member and further comprising a part extending in the space between a pair of said pole shoes, an end of said extending part being separated by a gap from another part of said peripheral portion so as to prevent a closed electric connection around a single one of said paired pole shoes.
Claim 2
Dependent Claim
168 words
A cathode ray tube comprising: a. an evacuated envelope; b. electron gun means for producing a plurality of electron beams; c. a luminescent screen and a color selection electrode located on the gun side of said screen; d. means for converging said electron beams in the plane of said color selection electrode, said converging means comprising a tubular member including a peripheral portion and a plurality of pairs of pole shoes employed for dynamically converging said electron beams and further comprising means for screening each one of said pairs of pole shoes from others of said pairs, said peripheral portion comprising spaced axial gaps through respective ones of which said pole shoes extend into said tubular member and further comprising a part extending in the space between a pair of said pole shoes, an end of said extending part being separated by a gap from another part of said peripheral portion so as to prevent a closed electric connection around a single one of said paired pole shoes.
Claim 3
Dependent Claim
26 words
A cathode ray tube as defined in claim 1, wherein said gap is located at the ends of one pair of said axial gaps associated therewith.
Claim 4
Dependent Claim
29 words
A cathode ray tube as defined in claim 1, wherein said gap is located at a point intermediate the ends of one pair of said axial gaps associated therewith.
Claim 5
Dependent Claim
20 words
A cathode ray tube as defined in claim 1, wherein said screening means comprises radial partitions within said cylindrical cup.
Claim 6
Dependent Claim
26 words
A cathode ray tube as defined in claim 1, wherein the axis of said gap is substantially transverse to the axes of associated said axial gaps.
References Cited (Backward Citations)
US3534208A
Cited
US3482137A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-16 | 1976-10-16 | 1977-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-16 | 1980-10-16 | 1981-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-16 | 1984-10-16 | 1985-04-17 | $7700.00 | Window Closed / Lapsed |