| 摘要 |
PURPOSE:To obtain a lamp with high efficiency and high color rendering by sealing the end openings of an emission tube bulb, which is made of a light- transmitting ceramic and consists of a spherical body of rotation the end portion of which has a smaller diameter than the central portion, by means of metallic sealing bodies which have a spherical surface of rotation and support electrodes. CONSTITUTION:An emission tube bulb 1 made of a light-transmitting ceramic consists of a part of a spherical body of rotation such as an ellipsoid the end portion 1a of which has a smaller diameter than the central portion 1b. Metallic sealing bodies 5 and 5 made of a thermoresistant corrosion-resistant metal such as niobium have a spherical surface of rotation continuous with the emission tube bulb 1. They are used to airtightly seal the end openings of the emission tube bulb 1 through sealing members such as glass solders 6 and 6. Electrodes 3 and 3 are supported at the centers of the metallic sealing bodies 5 and 5. Because of the above structure, the convection of steam within the emission tube 1 becomes more active and therefore it is possible to accelerate the equalization of the emission of the charged metal and the improvement of its efficiency. Therefore it is not necessary to install a heat-insulating body on the outer surface of the end section of the emission tube. |
