| 摘要 |
PURPOSE:To assure higher lamp efficiency as well as a flat characteristic of brightness distribution by providing electrodes on one ends of parallel two glass tubes, communicating the other ends thereof, and coating inner surfaces of the glass tubes with a reflecting film while leaving behind an opening part forming a prescribed angle. CONSTITUTION:Electrodes 3, 4 are respectively provided on one end parts of parallel two glass tubes 1, 2 containing mercury and rare gas encapsulated therein, and the other ends of the glass tubes 1, 2 are communicated with each other at a glass tube joint part 5. The inner surfaces of the glass tubes 1, 2 are coated with reflecting films 8, 9 while leaving opening parts 6, 7 forming a prescribed angle with respect to respective tube axes, and these films 8, 9 are coated with fluorescent films 10, 11. Hereby, an electrical discharge path is formed through the joint part 5, and the coldest portion is formed on the opposite side to the joint part 5 at the end part of the discharge path on the side having the joint path 5. Therefore, internal mercury vapor pressure can be limited by the coldest portion for assuring high lamp efficiency as well as a brightness distribution characteristic. |
