US4760310A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cathode-ray tubes and coating materials therefor
Assignee: Hitachi Ltd
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Filing: 1986-01-21
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Granted: 1988-07-26
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Expires: 2006-01-21
Abstract
Abstract A cathode-ray tube is coated on the inner surface with a coating material which contains, in a weight ratio based on solid, 10 to 22% of graphite, 30 to 50% of a metal oxide, 2 to 9% of a surface treating agent and 25 to 42% of water glass, and in which at least 18% of graphite powders in its simplest form suspended in said coating material have a particle size of at least 1 micron.
Inventors
- 👤 Sadao Deyama
- 👤 Toshiya Yamamoto
- 👤 Koichi Sakai
- 👤 Shigemi Hirasawa
- 👤 Tadao Kubo
- 👤 Yoshifumi Tomita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 22:18
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/86; H01J29/88; H01J2229/00; H01J2229/88; H01J2229/882
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
176 words
A coating material for a cathode-ray tube including a cathode ray tube envelope, an electron gun mounted in a neck portion of the envelope and a high voltage conductor mounted on a conical portion of the envelope, said electron gun being electrically connected to said conductor through a contactor of said electron gun and an electrically conductive coating film applied on the inner surface of said cathode-ray tube envelope, wherein said coating film has a specific resistance of at least 0.2 ohm.cm and a surface roughness of at least 6 microns, and a resistance value between said high-voltage conductor and said electron gun is in a range of 2 to 100 kohm, said coating material containing, in a weight ratio based on solid, 10 to 22% of graphite, 30 to 50% of a metal oxide, 2 to 9% of a surface treating agent and 25 to 42% of waterglass, and at least 18% of said graphite to be suspended in its simple form in said coating material having a particle size of at least 1 micron.
Claim 2
Dependent Claim
176 words
A coating material for a cathode-ray tube including a cathode ray tube envelope, an electron gun mounted in a neck portion of the envelope and a high voltage conductor mounted on a conical portion of the envelope, said electron gun being electrically connected to said conductor through a contactor of said electron gun and an electrically conductive coating film applied on the inner surface of said cathode-ray tube envelope, wherein said coating film has a specific resistance of at least 0.2 ohm.cm and a surface roughness of at least 6 microns, and a resistance value between said high-voltage conductor and said electron gun is in a range of 2 to 100 kohm, said coating material containing, in a weight ratio based on solid, 10 to 22% of graphite, 30 to 50% of a metal oxide, 2 to 9% of a surface treating agent and 25 to 42% of waterglass, and at least 18% of said graphite to be suspended in its simple form in said coating material having a particle size of at least 1 micron.
Claim 3
Dependent Claim
50 words
A coating material as defined in claim 1, wherein a part of said graphite is added in the form of a composite granulated powder with said metal oxide and surface treating agent, and another part of said graphite is added in the form of a powder in its simple form.
Claim 4
Dependent Claim
23 words
A coating material as defined in claim 1, wherein said metal oxide is titanium oxide, and said surface treating agent is silicon oxide.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-07-26 | 1992-01-25 | 1992-07-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-26 | 1996-01-25 | 1996-07-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-26 | 2000-01-25 | 2000-07-26 | $7700.00 | Window Closed / Lapsed |