US4251749A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Picture display tube having an internal resistive layer
Assignee: US Philips Corp
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Filing: 1978-11-08
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Granted: 1981-02-17
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Expires: 1998-11-08
Abstract
Abstract A picture display tube comprising an internal resistive layer to restrict the peak current which at the operating potential of the tube is associated with an electrical flash-over possibly occurring therein. The effective part of the resistive layer extends in the neck and over the transition from neck to cone of the envelope of the tube. The resistive layer represents a static resistance value of at most 10 4 Ohm and a dynamic resistance value of at least 300 Ohm.
Inventors
- 👤 Johannes M. A. A. Compen
- 👤 Reinhart C. W. Eisses
- 👤 Constantius J. W. Panis
- 👤 Cornelius J. H. Paridaens
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:29
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/86; H01J29/88
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
109 words
A picture display tube comprising an envelope having a display screen, an electrode system mounted in said envelope for generating at least one electron beam directed onto said screen, a resistive layer poured on at least a portion of the interior surface of said envelope near said electrode system, said layer having a dynamic resistance of at least 300 ohms, a static resistance less than 10,000 ohms and comprising a mixture of graphite particles having an average size less than 2 microns and generally spherical ferric oxide particles having an average size less than 2 microns, and means for electrically connecting said layer to a source of high voltage.
Claim 2
Dependent Claim
109 words
A picture display tube comprising an envelope having a display screen, an electrode system mounted in said envelope for generating at least one electron beam directed onto said screen, a resistive layer poured on at least a portion of the interior surface of said envelope near said electrode system, said layer having a dynamic resistance of at least 300 ohms, a static resistance less than 10,000 ohms and comprising a mixture of graphite particles having an average size less than 2 microns and generally spherical ferric oxide particles having an average size less than 2 microns, and means for electrically connecting said layer to a source of high voltage.
Claim 3
Dependent Claim
21 words
The picture tube according to claim 1 wherein said dynamic resistance of said resistive layer is between 300 and 3,000 ohms.
Claim 4
Dependent Claim
15 words
The display tube according to claim 1 wherein said mixture includes an alkaki metal silicate.
Claim 5
Dependent Claim
19 words
The display tube according to claim 1 wherein the thickness of said layer is between 5 and 20 microns.
Claim 6
Dependent Claim
39 words
The display tube according to claim 4 wherein said mixture consists essentially of one part by weight of graphite, 1.5 to 3 parts by weight of alkali metal silicate and 6 to 10 parts by weight of ferric oxide.
References Cited (Backward Citations)
US2223924A
Cited
US3791546A
Cited
DE2262547A1
Cited
US4052641A
Cited
US4041347A
Cited
US4018717A
Cited
US4092444A
Cited
US4124540A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-02-17 | 1984-08-18 | 1985-02-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-17 | 1988-08-18 | 1989-02-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-17 | 1992-08-18 | 1993-02-17 | $7700.00 | Window Closed / Lapsed |