US4398897A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of processing a cathode-ray tube for eliminating blocked apertures caused by charged particles
Assignee: RCA Licensing Corp
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Filing: 1981-07-28
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Granted: 1983-08-16
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Expires: 2001-07-28
Abstract
Abstract A method is proposed for eliminating so-called halo blocked apertures in color picture cathode-ray tubes. The cathode-ray tube comprises an evacuated envelope having therein a luminescent viewing screen, an electron gun for producing at least one electron beam for exciting the screen to luminescence and an apertured mask closely spaced from the screen for selectively intercepting and transmitting portions of the electron beam. A getter is provided for coating an interior surface of the apertured mask with a gas-sorbing, conductive getter material film. The halo blocked apertures are caused by insulative negatively-charged particles attached to the interior surface of the apertured mask. The conventional tube processing includes the steps of getter flashing, cathode discharge ball gap, cathode conversion, hot shot, first low voltage age, implosion proofing, external coating, frit breakdown check, radio frequency spot knock and final low voltage age. The improved method comprises controlling the getter flashing step so that the getter yields a primary film having about 50 to 75 percent of the available getter material. The getter is reactivated subsequent to the frit breakdown check step and before the final low voltage age step to provide a secondary film of getter material on the interior surface of the mask which will render conductive the insulative particles attached to the interior surface of the apertured mask.
Inventors
- 👤 Jawdat I. Nubani
- 👤 Frank S. Sawicki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 00:28
CPC Classifications
H; H01; H01J; H01J9/00; H01J9/38
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
139 words
In a method of processing a cathode-ray tube comprising an evacuated envelope having therein a luminescent viewing screen, means for producing at least one electron beam for exciting said screen to luminescence, an apertured mask closely spaced from said screen and gettering means for depositing a gas-sorbing, conductive getter material film on an interior surface of said mask, the method including the step of getter flashing, followed by further processing steps, the improvement comprising controlling said getter flashing step so that said getter means yields a primary film sufficient for gettering purposes and utilizing less than all of the available getter material, and reactivating said getter means subsequent to at least one of said further processing steps and before a final processing step to provide a secondary film of conductive getter material on said interior surface of said mask.
Claim 2
Dependent Claim
139 words
In a method of processing a cathode-ray tube comprising an evacuated envelope having therein a luminescent viewing screen, means for producing at least one electron beam for exciting said screen to luminescence, an apertured mask closely spaced from said screen and gettering means for depositing a gas-sorbing, conductive getter material film on an interior surface of said mask, the method including the step of getter flashing, followed by further processing steps, the improvement comprising controlling said getter flashing step so that said getter means yields a primary film sufficient for gettering purposes and utilizing less than all of the available getter material, and reactivating said getter means subsequent to at least one of said further processing steps and before a final processing step to provide a secondary film of conductive getter material on said interior surface of said mask.
Claim 3
Dependent Claim
24 words
The method of claim 1 wherein said primary film sufficient for gettering purposes utilizes about 50 to 75 percent of the available getter material.
Claim 4
Dependent Claim
144 words
In a method of processing a cathode-ray tube comprising an evacuated envelope having therein a luminescent viewing screen, means for producing at least one electron beam for exciting said screen to luminescence, an apertured mask closely spaced from said screen and gettering means for depositing a gas-sorbing, conductive getter material film on an interior surface of said mask, the method including the steps of getter flashing, frit breakdwon check, radio frequency spot knock and final low voltage age, the improvement comprising controlling said getter flashing step so that said getter means yields a primary film sufficient fo gettering purposes utilizing less than all of the available getter material, and reactivating said getter means subsequent to said frit breakdown check step and before said final low voltage aging step to provide a secondary film of conductive getter material on said interior surface of said mask.
Claim 5
Dependent Claim
144 words
In a method of processing a cathode-ray tube comprising an evacuated envelope having therein a luminescent viewing screen, means for producing at least one electron beam for exciting said screen to luminescence, an apertured mask closely spaced from said screen and gettering means for depositing a gas-sorbing, conductive getter material film on an interior surface of said mask, the method including the steps of getter flashing, frit breakdwon check, radio frequency spot knock and final low voltage age, the improvement comprising controlling said getter flashing step so that said getter means yields a primary film sufficient fo gettering purposes utilizing less than all of the available getter material, and reactivating said getter means subsequent to said frit breakdown check step and before said final low voltage aging step to provide a secondary film of conductive getter material on said interior surface of said mask.
Claim 6
Dependent Claim
24 words
The method of claim 3 wherein said primary film sufficient for gettering purposes utilizes about 50 to 75 percent of the avilable getter material.
Claim 7
Dependent Claim
37 words
The tube as in claim 1 or 3 wherein said reactivating step includes inductively heating said getter means for a period of time ranging from 30 to 60 seconds during which time an endothermic getter reaction occurs.
Claim 8
Dependent Claim
18 words
The tube as in claim 3 wherein said reactivating step occurs after said radio frequency spot knock step.
Claim 9
Dependent Claim
190 words
In a method of processing a completed cathode-ray tube including the steps of getter flashing, cathode discharge ball gap, cathode conversion, hot shot, first low voltage age, implosion proofing, external coating, frit breakdown check, radio frequency spot knock, and final low voltage age, said tube having an evacuated envelope with a conductive coating on an interior portion thereof, a luminescent viewing screen within said envelope, means for producing at least one electron beam for exciting said screen to luminescence, an apertured mask closely spaced from said screen and gettering means for depositing a gas-sorbing, conductive getter material on an interior surface of said mask, and on said interior conductive coating of said envelope, the improvement comprising: inductively heating said gettering means until an exothermic getter flash occurs, then terminating said inductive heating so that said gettering means yields a primary film having about 50 to 75 percent of the available getter material, and reactivating said getter means after said radio frequency spot knock so as to provide a secondary film of conductive getter material on said interior surface of said mask and on said interior conductive coating of said envelope.
Claim 10
Dependent Claim
190 words
In a method of processing a completed cathode-ray tube including the steps of getter flashing, cathode discharge ball gap, cathode conversion, hot shot, first low voltage age, implosion proofing, external coating, frit breakdown check, radio frequency spot knock, and final low voltage age, said tube having an evacuated envelope with a conductive coating on an interior portion thereof, a luminescent viewing screen within said envelope, means for producing at least one electron beam for exciting said screen to luminescence, an apertured mask closely spaced from said screen and gettering means for depositing a gas-sorbing, conductive getter material on an interior surface of said mask, and on said interior conductive coating of said envelope, the improvement comprising: inductively heating said gettering means until an exothermic getter flash occurs, then terminating said inductive heating so that said gettering means yields a primary film having about 50 to 75 percent of the available getter material, and reactivating said getter means after said radio frequency spot knock so as to provide a secondary film of conductive getter material on said interior surface of said mask and on said interior conductive coating of said envelope.
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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) | 1986-08-15 | 1987-02-14 | 1987-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-15 | 1991-02-14 | 1991-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-15 | 1995-02-14 | 1995-08-16 | $7700.00 | Window Closed / Lapsed |