| 摘要 |
A discharge lamp 1 satisfies relations of alpha1-alpha2>=3x10-7 and alpha2>alpha3, where alpha1 represents a thermal expansion coefficient [1/K] of a material of lead wires 5b and 6b, alpha2 represents a thermal expansion coefficient of a material of bead glasses 3 and 4, and alpha3 represents a thermal expansion coefficient of a material of a glass bulb 2. The discharge lamp 1 also satisfies relation of S1<S2, where S1 represents a strain point [° C.] of the material of the bead glasses 3 and 4 and S2 represents the material of the glass bulb 2. In the discharge lamp 1, tensile strains are unlikely to be created on the bead glasses or the glass bulb. As a result, a sealing part of the discharge lamp 1 can hardly crack during manufacture of the lamp.
|
