Abstract: A high-pressure discharge lamp includes a cathode body composed of a cathode made of tungsten or tungsten alloy and a lead rod inserted in a lead rod insertion hole of the cathode. The cathode has a carbonized layer made of tungsten carbide (W2C) formed on a surface thereof exposed to a discharge space (except for a tip portion thereof) and on an inner surface of the lead rod insertion hole. The carbonized layer contains carbon in an amount of 0.44 g/cc to 0.53 g/cc.

Abstract: A high-pressure discharge lamp includes a cathode body composed of a cathode made of tungsten or tungsten alloy and a lead rod inserted in a lead rod insertion hole of the cathode. The cathode has a carbonized layer made of tungsten carbide (W2C) formed on a surface thereof exposed to a discharge space (except for a tip portion thereof) and on an inner surface of the lead rod insertion hole. The carbonized layer contains carbon in an amount of 0.44 g/cc to 0.53 g/cc.

Abstract: In order to prevent a short lifetime of a lamp experiencing an extending downward of the coil under application stress when the coil is in a vertical configuration, there is provided an incandescent lamp in which a filament is stored in a bulb, and the filament is arranged in a vertical orientation and held by supporting element, where the filament is composed of a double coil in which a primary coil having a strand wound thereon is doubly wound, and the primary coil is more closely wound at the upper part of the filament than at the lower part of the filament.