Abstract: A metal vapor discharge lamp whose near-infrared radiation is stronger than a conventional high-pressure discharge lamp, a projector utilizing this discharge lamp, and a metal vapor discharge lamp lighting device are disclosed. The metal vapor discharge lamp comprises a refractory light-transmitting hermetic vessel, a pair of electrode fixed to the hermetic vessel, and a discharge medium sealed in the hermetic vessel and containing a halide and a rare gas. Most of the light irradiated when the discharge lamp is in the ON state has near-infrared wavelengths (750–1100 nm).

Abstract: A metal vapor discharge lamp whose near-infrared radiation is stronger than a conventional high-pressure discharge lamp, a projector utilizing this discharge lamp, and a metal vapor discharge lamp lighting device are disclosed. The metal vapor discharge lamp comprises a refractory light-transmitting hermetic vessel, a pair of electrode fixed to the hermetic vessel, and a discharge medium sealed in the hermetic vessel and containing a halide and a rare gas. Most of the light irradiated when the discharge lamp is in the ON state has near-infrared wavelengths (750-1100 nm).

Abstract: An incandescent lamp has an envelope including a cylindrical portion and two hemispherical portions. Each hemispherical portion includes a second order curve which has a focus and is connected at one end of the cylindrical portion, respectively. A filament is provided along the central axis of the envelope and is located within and extends beyond a space surrounded by the cylindrical portion. An optical interference layer is arranged on a surface of the envelope to reflect infrared rays and transmit visible rays.

Abstract: A headlight for a vehicle includes a metal halide lamp and a reflector having a focus and reflecting a light beam, emitted from the lamp, in a forward direction from the front of the vehicle. The lamp has a luminescent tube in which at least sodium is sealed, and positive and negative electrodes. The respective distal ends of the electrodes are located in the luminescent tube and spaced at a predetermined distance from each other. The lamp is positioned so that a straight line connecting the respective distal ends of the electrodes is horizontal and passes through the focus, and so as to meet the following requirement:0.ltoreq.L0/L1.ltoreq.0.4,where L0 is the distance between the focus and the distal end of the negative electrode, and L1 is the distance between the distal ends of the electrodes.

Abstract: A high pressure metal vapor discharge lamp including an outer bulb having a seal portion, an arc tube enclosed within the outer bulb, the arc tube having at least a pair of electrodes and containing at least a light emitting material and a rare gas, a pair of first lead wires of which one ends connect to the electrodes respectively and another ends mounted at the seal portion of outer bulb, a pre-heater disposed within the outer bulb, the pre-heater comprises a heat element and an insulating material covers the heat element and facing the arc tube to give the heat to the arc tube, and a second lead wires connected to the heat element of pre-heater, the portion of the second lead wires which are exposed in the outer bulb are surrounded by a heat-resisting insulator and the base portion of the second lead wires are mounted at the seal portion of outer bulb.