Ushio Denki Kabushiki Kaisha

Tomoyoshi Arimoto

Yoshikazu Suzuki

Akihiro Shimizu

Mitsuru Ikeuchi

Tadatoshi Higashi

Masashi Okamoto

Takashi Yamashita

Yukio Yasuda

Yukiharu Tagawa

Izumi Takaya

Hirohisa Iwabayashi

Katsumi Sugaya

Mitsuo Funakoshi

Katumi Sugaja

Minoru Fukuda

Kiyoyuki Kabuki

Kazuhiro Goto

Atsushi Imamura

Tetsuji Hirao

Tetsuya Kitagawa

Takuya Tsukamoto

Takumi Yamane

Masachika Ooyama

Shunichi Morimoto

Tetsu Okamoto

Shinji Nikawa

Masashi Dan

Kentaro Fujita

Takuya Tukamoto

Tomohiro Yamamoto

Taro Arimoto

Akiko Uchino

Katumi Sugaya

Yoshitaru Kondo

Yasuo Tanaka

Yuki Otoshima

Katsumi Sugaja

A high-pressure discharge lamp includes a cathode body composed of a cathode made of tungsten or tungsten alloy and a lead rod inserted in a lead rod insertion hole of the cathode. The cathode has a carbonized layer made of tungsten carbide (WC) formed on a surface thereof exposed to a discharge space (except for a tip portion thereof) and on an inner surface of the lead rod insertion hole. The carbonized layer contains carbon in an amount of 0.44 g/cc to 0.53 g/cc.

High-pressure discharge lamp

A discharge lamp includes an emitter other than thorium, which is added to a cathode in a luminous tube. Early depletion of the emitter due to excessive vaporization of the emitter from the cathode is prevented, while achieving stable lighting even at the start-up of the lighting. A main body part () of the cathode () is made from a high-melting-point metal material that contains no thorium, and a front end part () thereof is made from a high-melting-point metal material that contains an emitter (other than thorium). A sintered compact (), which contains an emitter (other than thorium) at a concentration higher than the emitter contained in the front end part (), is buried in a sealed space () that is formed within the main body part () and/or the front end part (). The sintered compact () abuts against the front end part ().

Discharge lamp

A discharge lamp includes a cathode in a luminous tube, and an emitter, other than thorium, is added to the cathode. The emitter is prevented from being excessively vaporized from the cathode and depleted soon. Smooth lighting is enabled even at start-up. A main body part () of the cathode () is made from a metallic material having a high melting point and containing no thorium. A front end () is made from a metallic material having a high melting point and containing an emitter (excepting thorium). Inside a sealed space () formed in the main body part () and/or the front end part () is received a sintered compact () containing an emitter (excepting thorium) that is higher in concentration than the emitter contained in the front end part ().

A short arc type discharge lamp wherein a cathode and an anode are arranged opposite to each other in an interior of a light emitting tube and said cathode comprises a main part made from tungsten and a tip end part made from thoriated tungsten, wherein thorium oxide particles having been peripherally coated with thorium are contained in the tip end part of said cathode.

Short arc type discharge lamp

A short arc type discharge lamp includes a cathode and an anode arranged inside an arc tube to face each other. The cathode comprises a main body portion made of tungsten and an emitter portion made of thoriated tungsten that is joined at the tip of the main body portion, where a metal oxide other than thorium (Th) is contained in the main body portion of the cathode, and a tungsten carbide layer is formed on the metal oxide.

A short arc type discharge lamp wherein a cathode and an anode are arranged opposite to each other in an interior of a light emitting tube and said cathode consists of a main body part with tungsten as the main constituent and an emitter part comprised of thoriated tungsten, wherein an oxygen content of the main body part of said cathode is lower than that of the emitter part, and band-shaped tungsten carbide is formed at the tip end face of the emitter part of said cathode.

A discharge lamp with excellent arc stability and excellent durability in which the use level of thoriated tungsten is restrained has an anode and a cathode in the interior of a discharge vessel, wherein said cathode is made up from a thoriated tungsten part with a tungsten filling ratio of at least 90 vol.-% and a main body part connected to said thoriated tungsten part and consisting of pure tungsten, wherein a ratio S/S of a side surface area Sof said thoriated tungsten part and a side surface area S of said cathode is in a range of from 0.005 to 0.15, with the proviso that, in case the cathode has a length in the direction of the cathode axis which exceeds twice the maximum diameter of the cathode, a side surface area S is used for calculating the ratio S/S which corresponds to the side surface area where the distance along the cathode axis from a tip end adjacent to the anode is twice the maximum diameter of the cathode.

Discharge lamp with an improved cathode of the type having a thoriated tungsten part

A high pressure discharge lamp light source device is provided having a quartz glass discharge vessel enclosing two opposed electrodes that are spaced apart by at most 2.0 mm, each electrode having a projection formed at a tip end thereof, at least 0.20 mg/mmof mercury and a halogen; and a power supply device for supplying alternating current to the lamp, The power supply device is adapted to switch between a nominal electric power lighting mode and a low electric power lighting mode having a defined current value in a range of 40 to 70% of a nominal electric power consumption. In the low power mode, the power supply alternately supplies a base current in a range between 100 Hz and 5 kHz a boost current having a higher current value than that of the base current.

High pressure discharge lamp light source device

A xenon short arc lamp for a digital projector, includes an anode, a cathode having a cathode main body that is made of tungsten containing electron emissive material, and an arc tube made of silica glass, wherein a supply source of carbon is formed on a metal portion in the arc tube except a tip area of the cathode, and the carbon is supplied to the tip of the cathode through a gaseous phase during lamp lighting, so that a surface layer of the cathode is melt.

Xenon short arc lamp for digital a projector

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.

High pressure discharge lamp lighting apparatus

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/mm, 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.

High pressure discharge lamp lighting device

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:

Device for operation of a discharge lamp of the short arc type

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/mmis 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.

Power supply apparatus for high pressure discharge lamp

To positionally stabilize the arc spot in a super-high pressure discharge lamp which is filled with at least 0.20 mg/mmof 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.

Device for operation of a high pressure discharge lamp

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 &#x3bc;H.

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Himeji, Japan

Tomoyoshi Arimoto