Ushio Denki Kabushiki Kaisha

Tetsuji Hirao

Koji Yamada

Hirohisa Iwabayashi

Tetsu Okamoto

Takashi Yamashita

Tomoyoshi Arimoto

Atsushi Imamura

Kentaro Fujita

Masaaki Uehara

Teppei Kagata

Atsushi Takama

A high pressure discharge lamp includes a light emission section in which a pair of electrodes is arranged, sealing portions formed from both ends of the light emission section, external leads, and a trigger wire provided near the light emission section. The trigger wire includes a first coil portion, which is wound from a vicinity of a boundary between the light emission section and one of the sealing portions towards an outer end of the one of sealing portions, and a linear stretch-across portion, which extends from the first coil portion near the light emission section towards the external lead extending from an outer end of the other sealing portion and is fixed to the external lead. A second coil portion is formed around the other sealing portion. The wire, which forms the stretch-across portion, is held between the second coil portion and the other sealing portion.

High pressure discharge lamp

A high pressure discharge lamp lighting apparatus that comprises a power supply apparatus that supplies a rectangle wave alternating current to the high pressure discharge lamp for lighting, such that when the lamp is operated by electric power of 0.5&#xd7;P (W) or less, when maximum operation power P (W) in a steady lighting state except an initial lighting period that is immediately after starting, where a first polarity driving period of a rectangle wave alternating current is Ta (seconds), and where a second polarity driving period is Tb (seconds) an operation is performed so that the second polarity driving period Tb is 5 ms or less (Tb&#x2266;5 ms) and a ratio Tb/Ta of these two driving periods is 0.1 or less (Tb/Ta&#x2266;0.1).

High pressure discharge lamp lighting apparatus and projector

A discharge lamp lighting apparatus comprises a discharge lamp and a power supply the discharge lamp can be switched between a steady power lighting mode, which drives the discharge lamp by an alternating current in which first and second polarities are repeated by turns, and a low power lighting mode, which drives the discharge lamp at 50% or less of the alternating current of the steady power lighting mode, and the alternating current comprises a first time unit, which has a time width t, and second time unit, which has a time width t, that are repeated by turns to drive the discharge lamp.

The present invention relates to a high pressure discharge lamp that includes a pair of electrodes, which face each other in an electric discharge space. Further, an electrode axis of one of the electrodes is joined to a metallic foil in a sealing portion, and two or more grooves are formed in an axis direction on a portion corresponding to the sealing portion on the electrode axis. Furthermore, a remaining portion that lacks grooves is left on the electrode axis in a metallic foil side thereof, and the metallic foil side ends of the grooves are not aligned with each other in the axis direction thereof.

High pressure discharge lamp with an electrode having alterating offset parallel grooves

To stabilize the arc bright point position of a discharge lamp and suppress deformation of an electrode when an ultrahigh-pressure discharge lamp is operated with extremely low electric power, the lamp is operated by supplying power from a power supply device having a step-down chopper circuit and a full bridge circuit, a rectangular wave alternating current being supplied when it is operated with rated power or dimmed power (about 60 to 80% of rated power), a DC current being supplied during standby power operation of at most 0.5&#xd7;P (W) with respect to the maximum operating power P (W). Moreover, the high-pressure discharge lamp light source device may be mounted on a projector for projecting images and the mode being changed to standby power operation when there is no change in an image signal, for example, for a prescribed period of time.

High-pressure discharge lamp light source device having a power supply device with a switching state for switching from a direct current drive in a standby state to an alternating current drive in an operating state and 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

A discharge lamp lighting apparatus for turning on a discharge lamp has a lighting condition in which a projection is formed at a tip of an electrode for electric discharge. In the discharge lamp lighting apparatus, when the polarity-reversal mode is the second mode, the inverter control circuit operates to generate the inverter control signal so that a DC component contained in the output current increases more than that in the first mode, when the polarity-reversal mode is the first mode, and it is detected that the lamp voltage is lower than a predetermined first voltage, the polarity-reversal mode control circuit changes the polarity-reversal mode into the second mode, and when the polarity-reversal mode is the second mode, and it is detected that the lamp voltage is higher than a predetermined second voltage, the polarity-reversal mode control circuit changes the polarity-reversal mode into the first mode.

Discharge lamp lighting apparatus and projector

To devise a light source device with a low price and from which a sufficient amount of light can be obtained, in a light source device having a reflector and a discharge lamp, a hermetically sealed portion of the lamp is directly joined to a part of a neck region of the reflector with a processed portion being formed for setting the positional relationship between the lamp and reflector.

Light source device

An ultrahigh pressure mercury lamp which is small and has high light radiation intensity and moreover good color reproduction with high efficiency in which, even with a large amount of mercury added, a failure of the mercury to vaporize in the bulb part does not occur, and in which blackening of the bulb part due to wearing of the electrodes even under a large electrode load as a result of shortening of the distance between the electrodes is low is obtained by an ultrahigh pressure mercury lamp in which a bulb part of the discharge vessel made of translucent material has an essentially ovoid shape, is filled with at least 0.2 mg/mmof mercury and which is operated at an input wattage of at most 400 W using direct current, has the length D of the tip area of the anode and the length L of the bulb part in the direction of the tube axis of the lamp set in accordance with the relationship D&#x2267;L/2.

Ultrahigh pressure mercury lamp with an anode configured to have a high thermal capacity

To devise an ultra-high pressure mercury lamp in which even in the case of lamp operation over a long time devitrification of the light emitting part is suppressed, an ultra-high pressure mercury lamp with a silica glass light emitting part in there is a pair of opposed electrodes, a rare gas, a halogen and at least 0.15 mg/mm of mercury, by the amount of halogen in the light emitting part being at least 1.0&times;10 &mgr;mol/mm and the amount of Mo in the light emitting part being at most 0.5&times;10 &mgr;mol/mm . Also, such a lamp can have an amount of halogen in the light emitting part of at least 2.0&times;10 &mgr;mol/mm with an amount of Mo of at most 1.0&times;10 &mgr;mol/mm .

Growing community of inventors

Hyogo, Japan

Tetsuji Hirao