Abstract: A light emitting device comprises: a concave mirror having one focal point; a plurality of main light sources each of which is arranged between the focal point and a light reflection surface of the concave mirror, and emits light toward the light reflection surface; and a plurality of main lenses each of which is arranged between a corresponding one of the main light sources and the light reflection surface, refracts the light emitted from the corresponding main light source toward the light reflection surface, and produces a virtual image of the main light source on the focal point situated at a backside of the main light source.

Abstract: A concave reflecting surface of a reflector for use in a light emitting device has micro reflector segments protruded therefrom in multiple stages and in multiple radial columns, the micro reflector segments each having a convex curved surface which is defined by a locus of a circular arc moved in parallel in a radial direction of the concave reflecting surface, and a radius of the convex curved surface, in each of the reflection regions, is set to be smaller when the convex curved surface is positioned closer to a point on which light emitted from each of the directional light sources and traveling on the light axis is incident, and is set to be larger when the convex curved surface is positioned more distant from the point.

Abstract: The image projection system is capable of freely adjusting a tone to suit user preferences. The system has a synchronization signal generating device that generates a synchronization signal composed of a plurality of on-off patterns in synchronism with rotation of a color filter and outputs each of predetermined power levels corresponding one-to-one with the on-off patterns to the high-pressure discharge lamp at fixed timing.

Abstract: To improve the startability of a discharge lamp by achieving a smooth transition from a glow discharge to an arc discharge.

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: 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: 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: There is provided an improved high-pressure discharge lamp which includes an arc tube encapsulating a halogen, and a pair of tungsten electrodes disposed in the arc tube. The oxygen content in the tungsten electrodes is not more than 15 ppm, while the amount of the encapsulated halogen lies in the range of 1×10?7 to 1×10?2 ?mol/mm3.

Abstract: An ultra-high pressure discharge lamp unit is provided which satisfies both of the demand for enhanced brightness and the demand for prolonged lifetime. The ultra-high pressure discharge lamp unit includes: a reflector having a concave reflective surface; an ultra-high pressure discharge lamp; and a translucent cover, the reflector having sidewall defining an exhaust vent hole opening into an air passage defined to extend along an external surface of the reflector. When air flows through the air passage, a flow rate difference results between the exterior and the interior of the reflector and, hence, the pressure exerted on the exterior along which air flows at a higher flow rate becomes lower than that exerted on the interior. Accordingly, heated air within the reflector is discharged out of the reflector through the exhaust vent hole by suction caused by the relatively low pressure.

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 high-pressure discharge lamp which includes an arc tube encapsulating a halogen, and a pair of tungsten electrodes disposed in the arc tube. The oxygen content in the tungsten electrodes is not more than 15 ppm, while the amount of the encapsulated halogen lies in the range of 1×10−7 to 1×10−2 &mgr;mol/mm3.