| 摘要 |
PURPOSE:To form easily annular metallized coating of a prescribed breadth on the inner surface of a bulb, by putting the bulb on a control cylinder placed in a metallizing pot and provided with a metallizing coil, and by arranging a control plate above the control cylinder, then by applying a current to the metallizing coil so as to evaporate metallizing metal. CONSTITUTION:A supporting stand 3, an under cylinder 4a of a control cylinder 4, and a metallizing coil 8 are installed in a metallizing pot 1. After a metallizing metal 5 is inserted into the metallizing coil 8, the under cylinder 4a is fitted with an upper cylinder 4b which supports a control circular plate 9 by means of a supporting wire 10. Then a bulb 11 is inserted into the metallizing pot 1. A current is applied to the metallizing coil 8 while the metallizing pot 1 and the bulb 11 being maintained at a vacuum with an on-off valve 2 opened. The metallizing metal is heated to be evaporated, controlled by the inner edge of the opening of the control cylinder 4 and the outer edge of the control plate 9 to form an annular metallized coating 12 of a prescribed breadth on the inner surface of the bulb 11. |
