| 摘要 |
PURPOSE:To form a film of uniform thickness efficiently without allowing occurrence of a flaw in a neck tube and the glass wall of a funnel, by forming a conductive film on the inner face of the funnel in which an anode button is enclosed and attached and then, completing glass bulb for a black-and-white picture tube by welding a panel to the funnel. CONSTITUTION:The best method to form a conductive film 13 is to insert a spray gun provided with a tank containing a solution of the mixture consisting of very fine carbon powder and phosphoric acid, from the end portion of the wide opening of a funnel 10 and to spray the solution toward the desired part of the inner face of the funnel 10 to form the coating. Said coating film 13 is formed from the circumference of the anode button 11 of the funnel 10 to the area near the welded part to a neck tube 12 and further on the whole inner face of the funnel 10. After forming the film 13 on the innerface of the funnel 10, a panel 14 is welded to the funnel 10 by means of a usual method, and a glass bulb B for a black-and-white picture tube is completed. |
