Low-voltage aging of cathode-ray tubes
AssigneeRCA Corporation
InventorPaul Richard Liller
Life of this patent
Estimating the term…
Abstract
During the low-voltage aging of a completely-assembled and operative cathode-ray tube, a varying positive voltage is applied to the focus electrode and a constant positive voltage is applied to the screen electrode while the cathode is emitting electrons. The effect is to cause electrons from the cathode to scan or spray across the electrode surfaces causing outgassing by electron bombardment of the scanned surfaces. This results in higher and more stable cathode-emission levels.
Claims10
In a method of processing a completed cathode-ray tube having an electron gun including a cathode, a control electrode, a screen electrode, a focus electrode and a high-voltage electrode, the method including the steps of spot-knocking, hot-shot, high-voltage aging and low-voltage aging, the improvement comprising applying a varying positive voltage to said focus electrode and a constant positive voltage to said screen electrode during the low-voltage aging step of said processing.
In a method for processing a completed cathode-ray tube having an electron gun comprising a cathode, a control electrode, a screen electrode, a focus electrode and a high-voltage electrode, the method including the steps of spot-knocking, hot-shot, high-voltage aging and low-voltage aging,
- during the low-voltage aging step, the step of applying ground voltage to said cathode and said control electrode, a constant positive voltage of about 300 to 400 volts to said screen electrode, a varying positive voltage to said focus electrode, said varying voltage having voltage peaks of at least 10% of said constant positive voltage, said cathode being operative to emit electrons and said high-voltage electrode being permitted to float electrically.
Dependencies are inferred from the claim text.