Abstract: A discharge lamp having a cathode containing lanthanum oxide (La2O3) as an electron emission material, to provide a discharge lamp where reduction of lanthanum oxide (La2O3) is accelerated; a supply amount of lanthanum (La); and its lifespan is long has an anode (4) and a cathode (5) arranged within a discharge vessel (1) so as to face toward each other in a tube axis direction of the discharge vessel (1), and the cathode (5) is made from a material containing a metal oxide of lanthanum (La2O3) and a metal oxide of zirconium (ZrO2) in a tungsten metal (W) substrate with carbon present as a solid solution in the tungsten metal (W) substrate forming the cathode (5).

Abstract: A discharge lamp lighting apparatus includes a discharge container, a pair of electrodes and a power supply apparatus. An alternating current of a frequency, which is lower than stationary frequency, is inserted periodically into the alternating current of stationary frequency. When a lighting current value of the discharge lamp is smaller than a predetermined lower limit, the frequency is set as predetermined minimum frequency. When the lighting current value of a discharge lamp is larger than a predetermined maximum value, the frequency is set as predetermined maximum frequency. When a lighting current value of the discharge lamp is between the lower limit and the maximum value, the frequency is set as a selected frequency corresponding to the lighting current value. The selected frequency increases according to an increase of frequency change as a lighting current value increases.

Abstract: A cathode for a discharge lamp contains emitter material, wherein a carbide layer is formed on an outer surface of the cathode, the carbide layer is formed on an area extending from a tip portion of the cathode, and two or more grooves extending toward the tip portion of the cathode are formed on the area where the carbide layer is formed.

Abstract: To shorten the luminous flux rise time and prevent melting/deformation of the projections in the initial ignition period of high pressure discharge lamps that have a sealed mercury volume of no less than 0.20 mg/mm3, a power supply device feeds a current that exceeds the maximum current value of the constant power control period to the high pressure discharge lamp during a first control period from the initial discharge until the lamp voltage reaches a specified lamp voltage and causes a switch to constant power control, and then, during the following period until a change to steady power control, the power supply device feeds it a current that is less than the maximum current during regular operation.

Abstract: A device for operating a discharge lamp of the short arc type having a feed device which supplies a direct current to the discharge lamp when operation starts and an alternating current afterwards, in which the feed device supplies a direct current which is smaller than the rated current to the discharge lamp at the start of operation, and a direct current which is at least as large as the rated current, afterwards. A control which ascertains whether the discharge lamp at the start of operation is in a hot or cold start operating state, and which establishes one of the following parameters based on whether the hot or cold operating state ascertained to exist: the value of the direct current which is at least as great as the rated current; the feed duration of the direct current which is at least as great as the rated current.

Abstract: To shorten the luminous flux rise time and prevent melting/deformation of the projections in the initial ignition period of high pressure discharge lamps that have a sealed mercury volume of no less than 0.20 mg/mm3, a power supply device feeds a current that exceeds the maximum current value of the constant power control period to the high pressure discharge lamp during a first control period from the initial discharge until the lamp voltage reaches a specified lamp voltage and causes a switch to constant power control, and then, during the following period until a change to steady power control, the power supply device feeds it a current that is less than the maximum current during regular operation.

Abstract: It is an object of the present invention to provide a high pressure discharge lamp capable of shifting to arc discharge without going out at initial lighting. The object of the invention is achieved by a high discharge lamp in which mercury of 0.15 mg/mm3 is enclosed, and a power supply apparatus. The power supply apparatus comprises a chopper circuit including a switching element, and a smoothing circuit including at least one smoothing capacitor connected to an output terminal of the chopper circuit, and a feedback system control circuit which drives the switching element of the chopper circuit, wherein a parallel circuit comprising a resistor and a second switching circuit is in series connected to an output terminal of the smoothing circuit, and at least at time of initial lighting, the second switching circuit is turned off, and when the lamp is stabilized, the second switching element is turned on.

Abstract: To positionally stabilize the arc spot in a super-high pressure discharge lamp which is filled with at least 0.20 mg/mm3 of mercury and to prevent the formation of so-called flicker, in an operation device having a high pressure discharge lamp and a feed device, the feed device of the high pressure discharge lamp supplies a frequency in the range from 60 Hz to 1000 Hz as the stationary operating frequency and a low frequency, in a frequency range of from 5 Hz to 200 Hz is inserted which has an inserted length of from one half period to five periods, and an inserting period of from 0.01 seconds to 120 seconds, into the alternating current of the stationary operating frequency. Furthermore, the parameters of the low frequency are changed according to changes of the operating voltage of the discharge lamp.

Abstract: A device for operating a discharge lamp of the alternating current operating type has a high pressure discharge lamp with a silica glass discharge vessel in which a pair of opposed electrodes are located and on which a trigger electrode is located, a feed device which supplies an alternating discharge current to the high pressure discharge lamp, the feed device having a starter circuit, an inverter circuit with at least two switching devices; a coil which is located downstream of the inverter circuit and is series-connected to the discharge lamp; and a control element which produces on/off driving in alternation with a dead time, and in which the inductance of the coil is at most 210 ?H.

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 ?mole/mm3 to 1×10?2 ?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 device for operating a discharge lamp of the short arc type having a feed device which supplies a direct current to the discharge lamp when operation starts and an alternating current afterwards, in which the feed device supplies a direct current which is smaller than the rated current to the discharge lamp at the start of operation, and a direct current which is at least as large as the rated current, afterwards. A control which ascertains whether the discharge lamp at the start of operation is in a hot or cold start operating state, and which establishes one of the following parameters based on whether the hot or cold operating state ascertained to exist: the value of the direct current which is at least as great as the rated current; the feed duration of the direct current which is at least as great as the rated current.

Abstract: To positionally stabilize the arc spot and to prevent the formation of so-called flicker, a super-high pressure discharge lamp which is filled with greater than or equal to 0.20 mg/mm3 of mercury has a feed device which supplies an alternating current with a steady-state operating frequency of from 60 Hz to 1000 Hz and a low frequency of from 5 Hz to 50 Hz. The feed device inserts the alternating current with the low frequency into the alternating current with the steady-state operating frequency with a time interval which has a length equal to at least one half period and at most to five periods, and the time interval being in the range of from 0.1 sec to 120 sec.

Abstract: It is an object of the present invention to provide a high pressure discharge lamp capable of shifting to arc discharge without going out at initial lighting. The object of the invention is achieved by a high discharge lamp in which mercury of 0.15 mg/mm3 is enclosed, and a power supply apparatus. The power supply apparatus comprises a chopper circuit including a switching element, and a smoothing circuit including at least one smoothing capacitor connected to an output terminal of the chopper circuit, and a feedback system control circuit which drives the switching element of the chopper circuit, wherein a parallel circuit comprising a resistor and a second switching circuit is in series connected to an output terminal of the smoothing circuit, and at least at time of initial lighting, the second switching circuit is turned off, and when the lamp is stabilized, the second switching element is turned on.

Abstract: To positionally stabilize the arc spot in a super-high pressure discharge lamp which is filled with at least 0.20 mg/mm3 of mercury and to prevent the formation of so-called flicker, in an operation device having a high pressure discharge lamp and a feed device, the feed device of the high pressure discharge lamp supplies a frequency in the range from 60 Hz to 1000 Hz as the stationary operating frequency and a low frequency, in a frequency range of from 5 Hz to 200 Hz is inserted which has an inserted length of from one half period to five periods, and an inserting period of from 0.01 seconds to 120 seconds, into the alternating current of the stationary operating frequency. Furthermore, the parameters of the low frequency are changed according to changes of the operating voltage of the discharge lamp.

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 positionally stabilize the arc spot and to prevent the formation of so-called flicker, a super-high pressure discharge lamp which is filled with greater than or equal to 0.20 mg/mm3 of mercury has a feed device which supplies an alternating current with a steady-state operating frequency of from 60 Hz to 1000 Hz and a low frequency of from 5 Hz to 50 Hz. The feed device inserts the alternating current with the low frequency into the alternating current with the steady-state operating frequency with a time interval which has a length equal to at least one half period and at most to five periods, and the time interval being in the range of from 0.1 sec to 120 sec.

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: 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: A device for operating a discharge lamp of the alternating current operating type has a high pressure discharge lamp with a silica glass discharge vessel in which a pair of opposed electrodes are located and on which a trigger electrode is located, a feed device which supplies an alternating discharge current to the high pressure discharge lamp, the feed device having a starter circuit, an inverter circuit with at least two switching devices; a coil which is located downstream of the inverter circuit and is series-connected to the discharge lamp; and a control element which produces on/off driving in alternation with a dead time, and in which the inductance of the coil is at most 210 ?H.

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.