Abstract: A light source apparatus is capable of reliably enhancing the starting performance of a high pressure discharge lamp even during hot state just after extinguishing the high pressure discharge lamp by radiating a necessary and sufficient amount of a UV-light into a discharge bulb of the lamp using an UV-enhancer of a simple constitution without increasing the manufacturing cost is provided. An UV-enhancer for radiating a UV-light to a discharge bulb for enhancing the starting performance of a high pressure discharge lamp upon starting lighting includes a discharge tube connected in parallel to a lighting circuit of the lamp, and an external electrode of the discharge tube is formed as a metal holder that holds the outer periphery of the discharge tube so as to oppose the end face of an electrode seal portion of the lamp inserted through a bottom hole in a concave reflector and secures the electrode seal portion to an electrode lead protruding from the end face thereof.

Abstract: A light source apparatus is capable of reliably enhancing the starting performance of a high pressure discharge lamp even during hot state just after extinguishing the high pressure discharge lamp by radiating a necessary and sufficient amount of a UV-light into a discharge bulb of the lamp using an UV-enhancer of a simple constitution without increasing the manufacturing cost is provided. An UV-enhancer for radiating a UV-light to a discharge bulb for enhancing the starting performance of a high pressure discharge lamp upon starting lighting includes a discharge tube connected in parallel to a lighting circuit of the lamp, and an external electrode of the discharge tube is formed as a metal holder that holds the outer periphery of the discharge tube so as to oppose the end face of an electrode seal portion of the lamp inserted through a bottom hole in a concave reflector and secures the electrode seal portion to an electrode lead protruding from the end face thereof.

Abstract: A high pressure discharge lamp according to the present invention is a high pressure discharge lamp in which the top ends of a pair of electrodes opposed in a discharge vessel 2 of an arc tube 1 are formed each into a substantially semispherical shape and a protrusion 10 to form an arc spot is formed at each top end, wherein all of the relation: 0.3••L/I••1.0 for an inter-electrode distance L(mm) between the electrodes and a lamp current I(A) during stable lighting, the relation: 1.2••10?7••X/Y••1.1••10?5 for a molar amount X(mol) of bromine in the bromide sealed in the discharge vessel 2 and an inner volume Y(ml) of the discharge vessel 2, and the relation: 9••W3/2/I••65, for a weight W(mg) of tungsten at the top end of each electrode 3 formed into a substantially semispherical shape are satisfied, and the lighting frequency of a rectangular wave during stable lighting is 45 Hz or higher.

Abstract: A high pressure discharge lamp according to the present invention is a high pressure discharge lamp in which the top ends of a pair of electrodes opposed in a discharge vessel 2 of an arc tube 1 are formed each into a substantially semispherical shape and a protrusion 10 to form an arc spot is formed at each top end, wherein all of the relation: 0.3••L/I••1.0 for an inter-electrode distance L(mm) between the electrodes and a lamp current I(A) during stable lighting, the relation: 1.2••10?7••X/Y••1.1••10?5 for a molar amount X(mol) of bromine in the bromide sealed in the discharge vessel 2 and an inner volume Y(ml) of the discharge vessel 2, and the relation: 9••W3/2/I••65, for a weight w(mg) of tungsten at the top end of each electrode 3 formed into a substantially semispherical shape are satisfied, and the lighting frequency of a rectangular wave during stable lighting is 45 Hz or higher.