Abstract: The present invention applies to provide a lighting method of a high pressure discharge lamp dedicated particularly for image equipments in which re-lighting when turning ON the switch again immediately after the switch OFF is instantaneously performed even in the high pressure discharge lamp. In the transition state of transitioning from the lighted state to light off, the lamp power to be supplied to the electrodes (3), (4) is reduced to an extent an arc discharge does not disappear and maintained for a while, and thereafter, transitioned to the glow discharge after lowering the lamp temperature to a temperature capable of maintaining the glow discharge and maintaining the glow discharge for a while, and the current supply to the electrodes (3), (4) is cut at the point the lamp temperature becomes lower than or equal to the temperature at which re-lighting is possible.

Abstract: An object of the invention is to provide method of operating a projection-type system, which method is capable of suppressing flicker and minimizing gradation disorder at the same time by superimposing a pulse current on a d.c. lamp current to stabilize arc while synchronizing the superimposition of the pulse current on the d.c. lamp current with a predetermined segment. The method of operating a projection-type system configured to pass light emitted from a high-pressure discharge lamp lit by d.c. lighting through divided plural color segments sequentially to project an image onto a screen, includes superimposing a pulse current on a d.c. lamp current in the high-pressure discharge lamp in synchronism with at least one specific color segment.

Abstract: A power supply unit capable of varying power supplied to a light source at timings determined by synchronization signals is provided. The power supply unit comprises an interface that receives a plurality of types of synchronization signals with different pulse widths and a control unit that changes a setting of output power supplied by the power supply unit in accordance with the pulse widths of the plurality of types of synchronization signals. The control unit includes obtaining a standard time interval from a cycle of a standard type of synchronization signal that has a longest pulse width, parsing for determining type of each synchronization signal, redefining supply power values corresponding to respective types of synchronization signals, and changing the setting of output power of the power supply unit to a supply power value corresponding to a type of the synchronization signal.

Abstract: To prevent scattering of broken pieces of a reflecting mirror even if a high pressure discharge lamp with a reflector bursts. A light source device according to the present invention is a light source device 10 that has an arc tube 1 and a reflector 2, and a cover glass 4 is externally fitted and fixed to the rear of the reflector 2 at opposite ends thereof with a gap S therebetween. With such a configuration, even if the arc tube bursts to cause a crack in the reflector, the cover glass prevents scattering of the broken pieces of the reflector.

Abstract: The high-pressure discharge lamp includes: a pre-seal glass inserted in the internal space of each of seal portions and integrally comprising a metal foil sheathing portion which sheathes a metal foil, an electrode sheathing portion which sheathes a portion of an electrode that extends from a first end of the metal foil toward a base portion and an external lead pin sheathing portion which sheathes a portion of an external lead pin that extends outwardly from the other end of the metal foil; and a conductor for generating discharge between the conductor and the metal foil. The electrode sheathing portion is fused to the base portion. The external lead pin sheathing portion has an outer surface hermetically fused to an inner surface of one of the seal portions. A clearance hermetically sealed between the pre-seal glass and the seal portion encapsulates inert gas therein.

Abstract: A power supply unit capable of varying power supplied to a light source at timings determined by synchronization signals is provided. The power supply unit comprises an interface that receives a plurality of types of synchronization signals with different pulse widths and a control unit that changes a setting of output power supplied by the power supply unit in accordance with the pulse widths of the plurality of types of synchronization signals. The control unit includes obtaining a standard time interval from a cycle of a standard type of synchronization signal that has a longest pulse width, parsing for determining type of each synchronization signal, redefining supply power values corresponding to respective types of synchronization signals, and changing the setting of output power of the power supply unit to a supply power value corresponding to a type of the synchronization signal.

Abstract: To provide a lighting circuit of a projector that can be driven by both the commercial alternating-current power supply and a battery and is convenient for portable use.

Abstract: This invention makes it possible to use a concave reflection mirror using metal in at least a concave reflective portion thereof for discharge lamps. The concave reflection mirror is characterized by including: a metallic concave reflective portion; and a neck portion for receiving therein a high voltage side seal portion of a high-pressure discharge lamp to be continuously applied with a d.c. voltage of 1000 V to 4000 V during an ignition phase, the neck portion protruding rearward from a central portion of the metallic concave reflective portion and being formed partially of an insulating member or entirely of an insulating material. The concave reflection mirror can have a concave reflective surface with improved curved surface precision thereby making it possible to reduce variations in brightness, use a multi-layered deposited film having a low heat resistance, and reduce the required cost considerably.

Abstract: This invention provides a method of operating a projection system wherein light emitted from a high-pressure discharge lamp being lit with d.c. lamp current is passed through color segments of a color filter sequentially and then reflected by an optical element to project an image on a screen, the color segments of the color filter including red, green and blue color segments and a color segment comprising a green ND filter having a relatively low lightness. The method includes making lower a crest value of the d.c. lamp current fed to the high-pressure discharge lamp for a first illumination period during which the color segment comprising the green ND filter is illuminated than a crest value of the d.c. lamp current fed to the high-pressure discharge lamp for a second illumination period during which any one of the other color segments is illuminated, in synchronism with the first illumination period.

Abstract: To prevent scattering of broken pieces of a reflecting mirror even if a high pressure discharge lamp with a reflector bursts. A light source device according to the present invention is a light source device 10 that has an arc tube 1 and a reflector 2, and a cover glass 4 is externally fitted and fixed to the rear of the reflector 2 at opposite ends thereof with a gap S therebetween. With such a configuration, even if the arc tube bursts to cause a crack in the reflector, the cover glass prevents scattering of the broken pieces of the reflector.

Abstract: The present invention applies to provide a lighting method of a high pressure discharge lamp dedicated particularly for image equipments in which re-lighting when turning ON the switch again immediately after the switch OFF is instantaneously performed even in the high pressure discharge lamp. In the transition state of transitioning from the lighted state to light off, the lamp power to be supplied to the electrodes (3), (4) is reduced to an extent an arc discharge does not disappear and maintained for a while, and thereafter, transitioned to the glow discharge after lowering the lamp temperature to a temperature capable of maintaining the glow discharge and maintaining the glow discharge for a while, and the current supply to the electrodes (3), (4) is cut at the point the lamp temperature becomes lower than or equal to the temperature at which re-lighting is possible.

Abstract: An object of the present invention is to make it possible to record information on an optical information recording medium in the form of three dimensional interference patterns so that the information is erasable in part. The optical information recording medium (1) has an information recording layer (3) made of a magneto-optic recording material. A pick-up (11) of an optical information recording/reproducing apparatus generates information light by spatially modulating laser light emitted from a light source unit (20) with a spatial light modulator (22), and generates recording-specific reference light spatially modulated in phase by spatially modulating the phase of the laser light emitted from the light source (20) with a phase-spatial light modulator (16). The information recording layer (3) of the optical information recording medium (1) is irradiated with the information light and the recording-specific reference light.

Abstract: An object of the invention is to provide method of operating a projection-type system, which method is capable of suppressing flicker and minimizing gradation disorder at the same time by superimposing a pulse current on a d.c. lamp current to stabilize arc while synchronizing the superimposition of the pulse current on the d.c. lamp current with a predetermined segment. The method of operating a projection-type system configured to pass light emitted from a high-pressure discharge lamp lit by d.c. lighting through divided plural color segments sequentially to project an image onto a screen, includes superimposing a pulse current on a d.c. lamp current in the high-pressure discharge lamp in synchronism with at least one specific color segment.

Abstract: To provide a lighting circuit of a projector that can be driven by both the commercial alternating-current power supply and a battery and is convenient for portable use.

Abstract: This invention provides a method of operating a projection system wherein light emitted from a high-pressure discharge lamp being lit with d.c. lamp current is passed through color segments of a color filter sequentially and then reflected by an optical element to project an image on a screen, the color segments of the color filter including red, green and blue color segments and a color segment comprising a green ND filter having a relatively low lightness. The method includes making lower a crest value of the d.c. lamp current fed to the high-pressure discharge lamp for a first illumination period during which the color segment comprising the green ND filter is illuminated than a crest value of the d.c. lamp current fed to the high-pressure discharge lamp for a second illumination period during which any one of the other color segments is illuminated, in synchronism with the first illumination period.

Abstract: Improved method and device for lighting a high pressure discharge lamp are provided which prevent arc jump and inhibit deterioration of lamp voltage and luminance. The method includes the step of: alternately repeating a superposition operation for superposing a pulse current on a lamp current applied to the high pressure discharge lamp for a predetermined time period and a superposition stopping operation for stopping the superposition of the pulse current for a predetermined time period.

Abstract: There is provided an improved method of lighting an ultra-high pressure discharge lamp in which a pair of electrodes are disposed confronting each other with a spacing of not more than 1.5 mm therebetween in an arc tube forming part of an envelope of quartz glass, the arc tube encapsulating mercury in an amount of 0.15 mg/mm3, the method including the steps of: reducing a lamp power supplied to the pair of electrodes to a degree such as not to stop arc discharge in a transition state from a lighting state to extinction; keeping the lamp power thus reduced for a predetermined time period; and shutting down the supply of current to the electrodes.

Abstract: This invention provides a magnetic optical member that can obtain a large magneto-optical effect using a rare-earth iron-garnet-based material and a method of producing the same.

Abstract: Improved method and device for lighting a high pressure discharge lamp are provided which prevent arc jump and inhibit deterioration of lamp voltage and luminance. The method includes the step of: alternately repeating a superposition operation for superposing a pulse current on a lamp current applied to the high pressure discharge lamp for a predetermined time period and a superposition stopping operation for stopping the superposition of the pulse current for a predetermined time period.

Abstract: There is provided an improved method of lighting an ultra-high pressure discharge lamp in which a pair of electrodes are disposed confronting each other with a spacing of not more than 1.5 mm therebetween in an arc tube forming part of an envelope of quartz glass, the arc tube encapsulating mercury in an amount of 0.15 mg/mm3, the method including the steps of: reducing a lamp power supplied to the pair of electrodes to a degree such as not to stop arc discharge in a transition state from a lighting state to extinction; keeping the lamp power thus reduced for a predetermined time period; and shutting down the supply of current to the electrodes.