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AssigneeRCA Corporation
InventorsJawdat I. Nubani, Frank S. Sawicki
Estimating the term…
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.
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
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
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:
Dependencies are inferred from the claim text.