| 摘要 |
PROBLEM TO BE SOLVED: To provide a heating lamp having great electric power by using a functionally gradient material for a sealer to clarify the conditions that a current can flow in a sealed portion with high current density, which cannot flow in a conventional foil sealed structure. SOLUTION: The lamp using the sealer of a functionally gradient material has a lamp container of a silica glass, the lamp container being sealed by the sealer of the functionally gradient material which has an electric resistivity and a thermal expansion coefficient being smaller at one end in the axial direction and larger at the other end with the content of silica and molybdenum changed in an approximately continuous or stepwise manner in the axial direction. A current introducing rod is held passing through the sealer and a filament coil is connected to the current introducing rod protruded from the front part of the sealer into the lamp container. The sealer can be used with the rear end face having a temperature of 500 deg.C or lower by satisfying a relationship, R>=d and (1/πR2)<=1.03, where R(mm) is the radius of the rear end face of the sealer of the functionally gradient material, d(mm) is the diameter of the current introducing rod and IL(A) is a value for a current flowing in the current introducing rod.
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