Abstract: A high pressure discharge lamp, in which an anode and a cathode are disposed opposite each other in a bulb, achieves a long service life due to thorium (Th) being stably supplied to the cathode tip for a long time after lamp operation has been commence since the formation of the flicker phenomenon is suppressed over a long time due to the cathode being made of tungsten which contains thorium oxide on a surface space from the cathode tip, a carbide layer of tungsten carbide is formed and the cathode being bordered by an emitter containing body of tungsten which contains thorium dioxide, and a carbide layer of tungsten carbide being formed at least in a region bordering the cathode.

Abstract: To devise a small light source device in which breaking of the bulb of the light source lamp can be suppressed and in which breaking of the bulb will not damage the window component, a light source lamp supported in a housing by only one of two hermetically sealed tubes at opposite ends of an arc tube, a cooling rib is mounted on a lead pin in the one of the sealed tubes that faces toward the window component and has a larger dimension in the radial direction than the maximum diameter of the opening edge of the light exit opening in the housing. The cooling rib serves to block bulb fragments and should it contact the peripheral edge area of the light exit opening with its edge that faces the window component, due to its size, neither the lead pin nor the cooling rib will contact the window component.

Abstract: A discharge lamp of the short arc type in which the temperature rise of the sealing components of graded glass within the sealing part can be suppressed and in which the sealing components are not damaged is achieved, in a such lamp that has sealing parts which border the arc tube on opposite sides, and lead pins which each support a electrode in the arc tube, and are sealed within the respective sealing part by graded glass, by a component for cooling the sealing part being provided on the outside of at least one of the sealing parts, and by a component for cooling the lead pin being provided on at least one of the lead pins, in the area in which it projects outward from the graded glass within the sealing part which is provided with the component for cooling the sealing part.

Abstract: A lamp primarily containing neon gas is supplied with alternating electrical power at a frequency of not less than 5 kHz. The discharge current is determined on the basis of the gas pressure such that no striations occur. If necessary, getter means including a metal element belonging to the second, third, fourth or fifth periodic group are provided near each electrode, oriented so as not to interfere with any electron emissions from the lamp electrodes.