Abstract: Alternating current with rectangular waves is supplied from an operating device to an ultra-high pressure discharge lamp in which located within a silica glass discharge vessel is a pair of opposed electrodes separated by a distance of less than or equal to 1.5 mm. A discharge vessel is filled with greater than or equal to 0.15 mg/mm3 mercury and bromine in the range of 10?6 ?mol/mm3 to 10?2 ?mol/mm3. In the operating device, a multiplication device computes the discharge wattage supplied to the discharge lamp and controlled so that in the case of a reduction of the operating voltage of the discharge lamp the discharge wattage is reduced, and that in the case of an increase of the operating voltage of the discharge lamp the discharge wattage is increased.

Abstract: A short arc ultra-high pressure mercury lamp, at least one of the electrodes of which has a melted part towards the electrode head and a coil part which extends from the melted part continuously and integrally with it in a direction away from the electrode head, avoids blackening of the tube wall and achieves a long service life by the provision of a power supply which supplies the discharge lamp with direct current when operation is starting and afterwards supplies it with an alternating current, the direct current supplied by the power supply to the discharge lamp being initially 0.3 to 0.6 times as great as the rated current and afterwards increasing to 1.0 to 2.0 times are great as the rated current.

Abstract: To prevent lamp extinction during dead time of an inverter circuit of a full bridge system, to reduce delays of the rising time and the falling time of rectangular waves which have been output by the inverter circuit and to prevent formation of a phenomenon of momentary darkening of the radiant light, the discharge lamp is operated with an alternating current with rectangular waves which is produced by an inverter circuit of a full bridge system. When the inverter circuit of the full bridge system is driven a dead time is taken in which all switching devices are turned off. In the rear stage of the inverter circuit of the full bridge system, there is an inductance. The value of the inductance is fixed such that LL≧VL/IL·Td (VL being the luminous voltage of the discharge lamp, IL being the current and Td the dead time). Current can flow in the discharge lamp during the dead time by the energy stored in this inductance.

Abstract: An emission device for an ultra-high pressure mercury lamp which maintains an electrode tip shape by which a stable discharge can always be carried out is achieved for a short arc ultra-high pressure mercury lamp with silica glass arc tube containing a pair of opposed electrodes spaced apart a distance of at most 2 mm and in which the arc tube is filled with at least 0.15 mg/mm3 of mercury, a rare gas and a halogen in the range from 1×10−6 &mgr;mole/mm3 to 1×10−2 &mgr;mole/mm3; by providing an operating device which produces a current feed by which the surface of the tip of at least one of the electrodes is shifted into a molten state during lamp operation.

Abstract: A light source device in which the operating characteristic of the auxiliary light source can be improved, in which the starting property within the main discharge vessel is extremely advantageous and which has high reliability with respect to vibration resistance and impact strength without the disadvantage of a cost increase due to the complicated arrangement of the light source device, without reducing the proportion of good articles in the manufacture of the products, and without reducing the quality of the discharge lamp is achieved using a main discharge lamp mounted in a reflector with an auxiliary light source tightly held by the reflector or components which are adjacent to the reflector and without contact with the main discharge vessel.

Abstract: An ultra-high pressure high pressure discharge lamp device in which the lamp voltage and the distance between the lamp electrodes can be kept stable is achieved by an operating device supplying an alternating current with rectangular waves to the discharge lamp and control is exercised such that a lower boundary value is set and the operating voltage is increased by reducing the operating frequency of the discharge lamp by a given amount, when the operating voltage of the discharge lamp is below the set lower boundary value. Furthermore, control can also be exercised in such a way that an upper boundary value is set and the operating voltage is reduced by increasing the operating frequency of the discharge lamp by a given amount when the operating voltage of the discharge lamp exceeds the set upper boundary value.

Abstract: Alternating current with rectangular waves is supplied from an operating device to an ultra-high pressure discharge lamp in which located within a silica glass discharge vessel is a pair of opposed electrodes separated by a distance of less than or equal to 1.5 mm. A discharge vessel is filled with greater than or equal to 0.15 mg/mm3 mercury and bromine in the range of 10−6 &mgr;mol/mm3 to 10−2 &mgr;mol/mm3. In the operating device, a multiplication device computes the discharge wattage supplied to the discharge lamp and controlled so that in the case of a reduction of the operating voltage of the discharge lamp the discharge wattage is reduced, and that in the case of an increase of the operating voltage of the discharge lamp the discharge wattage is increased.

Abstract: A device which improves the starting of a high pressure discharge lamp containing a large amount of mercury, in which the amount of mercury adhering to the lamp electrodes is not the same, by shortening the formation time of the glow discharge in order to reduce the sputtering of the electrodes to a minimum. When the discharge lamp starts, an AC voltage with rectangular waves produced by the full bridge circuit is applied to the discharge lamp. Next, a high voltage pulse is superimposed and applied by an igniter device; the pulse is synchronized to the polarity of the above described AC voltage with rectangular waves. As a result, an alternating current discharge is started in the discharge lamp. Then, the ON/OFF state of the switching devices in the full bridge circuit is fixed and a direct current voltage is applied to the lamp. After a pre-selected time has expired after the transition into direct current operation, the full bridge circuit is operated such that rectangular alternating current waves form.

Abstract: To prevent lamp extinction during dead time of an inverter circuit of a full bridge system, to reduce delays of the rising time and the falling time of rectangular waves which have been output by the inverter circuit and to prevent formation of a phenomenon of momentary darkening of the radiant light, the discharge lamp is operated with an alternating current with rectangular waves which is produced by an inverter circuit of a full bridge system. When the inverter circuit of the full bridge system is driven a dead time is taken in which all switching devices are turned off. In the rear stage of the inverter circuit of the full bridge system, there is an inductance. The value of the inductance is fixed such that LL≧VL/IL·Td (VL being the luminous voltage of the discharge lamp, IL being the current and Td the dead time). Current can flow in the discharge lamp during the dead time by the energy stored in this inductance.

Abstract: To provide a high-pressure mercury lamp capable of shortening the light output rise time and of preventing glow discharge that occurs when the lamp is lighted, a high-pressure mercury lamp (1) luminescent device with a pair of electrodes (6, 7) placed opposite one another within a discharge vessel (2) made of quartz glass with seals (4, 5) formed on both ends and at least 0.15 mg/mm3 of mercury sealed into the discharge vessel, has a device (11, 12) for increasing the temperature of the outer wall of the luminescent portion (3) of the discharge vessel (2) to at least 100° C. before the high-pressure mercury lamp is lit.

Abstract: To provide a high-pressure mercury lamp capable of shortening the light output rise time and of preventing glow discharge that occurs when the lamp is lighted, a high-pressure mercury lamp (1) luminescent device with a pair of electrodes (6, 7) placed opposite one another within a discharge vessel (2) made of quartz glass with seals (4, 5) formed on both ends and at least 0.15 mg/mm3 of mercury sealed into the discharge vessel, has a device (11, 12) for increasing the temperature of the outer wall of the luminescent portion (3) of the discharge vessel (2) to at least 100° C. before the high-pressure mercury lamp is lit.

Abstract: To provide a power supply device for electric discharge lamps in which lamp extinguishing is completely prevented in high-pressure mercury vapor lamps with a comparatively large amount of mercury sealed within, is achieved through the use of a switchable connection from the connection state of a simulated arc discharge resistor (59) virtually equal to the arc discharge resistance of the high-pressure mercury vapor lamp to the connection state of simulated glow discharge resistors (59, 60) that have virtually {fraction (1/7)} of the glow discharge resistance that is completed at the output terminal of the power supply device (2) for the electric discharge lamps in question.

Abstract: The invention relates to a high pressure mercury lamp which is operated with an internal pressure at least equal to one hundred and some dozen atm and in which the thermal load and gas convection are considered. A fused silica glass discharge vessel is filled with mercury in an amount at least equal to 0.15 mg/mm3 and rare gas. The length of the electrode which projects into the discharge vessel and which is positioned at the top is greater than the length of the electrode which projects into the discharge vessel and which is positioned at the bottom. Where the lamp wattage is W (W) and the maximum value of the inside diameter in the direction perpendicular to the axis which extends between the pair of electrodes within the discharge vessel is D (mm), the following conditions are met: 0.35×(W)½≦L1≦0.69×(W)½ L2≦0.76×(W){fraction (1/2.64)} and at the same time (2.50)e0.0022W≦D≦(5.0)e0.0034W.

Abstract: A light source device for a liquid crystal projector in which it is possible to prevent distinct appearance of a shadow of the conducting wiring of a lamp on a screen, even if an integrator lens is used, is achieved according to the invention by the fact that, in a light source device which has a metal halide lamp with bilateral sealed terminations in which seal areas are joined in one piece to two ends of an arc tube, and a concave reflector, in which one of the seal areas of the lamp is installed and held in a base opening of the concave reflector, and in which the other seal area extends in toward the front opening of the concave reflector, by conducting wiring connected to the outer lead pin which projects from the seal area toward the front opening of the concave reflector being positioned running toward the arc tube in a manner resting directly on this seal area, and then being drawn out in the vicinity of the arc tube with to behind the concave reflector.

Abstract: To minimize "color hue" and "flickering" on an irradiated surface such as a screen or the like, is achieved by the fact that, in a metal halide lamp of the short arc type which has a cathode and an anode in which at least rare earth halides and mercury are encapsulated and which is operated with an essentially horizontal discharge direction using direct current power, the cathode has a tungsten electrode shaft about which a tungsten coil is wound, and the relationship 0.029<S/I<0.076 is satisfied where S is the cross section of the electrode shaft (mm.sup.2) and I the current in steady-state luminous operation (A). In accordance with another aspect of the invention, the lamp is operable with a current I (amperes) in steady-state luminous operation in a range from 1.6<I<5.0 and the anode has a tip formed of a roughly cylindrical rod with a bevelled edge between a blunt end of the rod and a peripheral surface of the rod, and with the relationship of the current I and the area S of the blunt end (mm.

Abstract: A metal halide lamp in which rare earth halides are encapsulated and the occurrence of milky cloudiness is suppressed to achieve a prolongation of the service life of the lamp. To achieve this result, inert gas, mercury, indium halide, cesium halide, and rare earth halides are encapsulated in an emission part, with the encapsulation amount of the indium halide being from 0.8 micromole to 8.0 micromole/cm.sup.3 of tube volume, and the lamp is operated with an essentially horizontal arc axis using a direct current. Furthermore, iodine and bromine are contained in the halogen which forms the halides, and there is a ratio of the iodine atom number to the total halogen atom number is greater than or equal to 50%.