Abstract: An electric discharge lamp has a ceramic luminous tube 5 and filled with xenon gas, a pair of electrodes 9, 10 held by the ceramic luminous tube, and a glass outer tube 6 accommodating the ceramic luminous tube and the pair of electrodes. The ceramic luminous tube includes a luminous portion 7 emitting light by electric discharge, and a pair of small diameter tube portions 8, 8 respectively connected to both end portions of the luminous portion in a longitudinal direction. Value of P/(r•t) is not less than 4.8 and not more than 32, where P (atm) is pressure of xenon gas filled into the ceramic luminous tube, r (mm) is an inner diameter of the luminous portion of the ceramic luminous tube, and t (mm) is thickness of the luminous portion of the ceramic luminous tube.

Abstract: A discharge lamp for a vehicle has an external tube attached to a socket, a light emitting tube disposed in the external tube and formed of ceramic, the light emitting tube including a light emitting portion and a pair of narrow tube portions linked to the light emitting portion at opposite sides with the light emitting portion interposed therebetween, a cathode side electrode and an anode side electrode which are disposed in the light emitting tube, and two lead wires connected to the cathode side electrode and the anode side electrode respectively and having at least a part disposed in the external tube respectively. A length of the narrow tube portion on the cathode side being set to be smaller than that of the narrow tube portion on the anode side. The cathode side electrode being disposed on an opposite side to the socket with the anode side electrode interposed therebetween.

Abstract: There is provided a mercury-free discharge bulb for a vehicle. The mercury-free discharge bulb includes an arc tube. The arc tube includes: a light-emitting portion which is formed of a ceramic tube and includes a light-emitting material and a starting xenon gas filled therein, wherein a filling pressure of the starting xenon gas from about 6 atm to about 18 atm; thin tube portions which are formed at respective ends of the light-emitting portion; and electrodes which are fixed inside the thin tube portions and which are provided in the light-emitting portion so as to face each other. The light-emitting material includes at least a sodium halide and a rare-earth metal halide excluding a scandium halide, and a difference between a vapor pressure of the sodium halide and a vapor pressure of the rare-earth metal halide under an environment of about 1000° C. is about 10 kPa or less.

Abstract: A discharge lamp for a vehicle is provided with a ceramic luminous tube, a front side electrode and a rear side electrode held by the ceramic luminous tube, a first lead wire connected to the front side electrode, a second lead wire connected to the rear side electrode, a third lead wire having a front end portion connected to the first lead wire, an outer tube, and a socket. The ceramic luminous tube, the first lead wire, the second lead wire and the third lead wire are accommodated in the outer tube. The ceramic luminous tube includes a luminous portion and a pair of small diameter tube portions. The luminous portion is formed into a substantially cylindrical shape extending in a longitudinal direction. The third lead wire includes a horizontal portion extending in the longitudinal direction above the luminous portion.

Abstract: There is provided a mercury-free discharge bulb for a vehicle. The mercury-free discharge bulb includes an arc tube. The arc tube includes: a light-emitting portion which is formed of a ceramic tube and includes a light-emitting material and a starting xenon gas filled therein, wherein a filling pressure of the starting xenon gas from about 6 atm to about 18 atm; thin tube portions which are formed at respective ends of the light-emitting portion; and electrodes which are fixed inside the thin tube portions and which are provided in the light-emitting portion so as to face each other. The light-emitting material includes at least a sodium halide and a rare-earth metal halide excluding a scandium halide, and a difference between a vapor pressure of the sodium halide and a vapor pressure of the rare-earth metal halide under an environment of about 1000° C. is about 10 kPa or less.

Abstract: A discharge lamp for a vehicle is provided with a ceramic luminous tube, a front side electrode and a rear side electrode held by the ceramic luminous tube, a first lead wire connected to the front side electrode, a second lead wire connected to the rear side electrode, a third lead wire having a front end portion connected to the first lead wire, an outer tube, and a socket. The ceramic luminous tube, the first lead wire, the second lead wire and the third lead wire are accommodated in the outer tube. The ceramic luminous tube includes a luminous portion and a pair of small diameter tube portions. The luminous portion is formed into a substantially cylindrical shape extending in a longitudinal direction. The third lead wire includes a horizontal portion extending in the longitudinal direction above the luminous portion.

Abstract: An electric discharge lamp has a ceramic luminous tube and filled with xenon gas, a pair of electrodes 9, 10 held by the ceramic luminous tube, and a glass outer tube 6 accommodating the ceramic luminous tube and the pair of electrodes. The ceramic luminous tube includes a luminous portion 7 emitting light by electric discharge, and a pair of small diameter tube portions 8, 8 respectively connected to both end portions of the luminous portion in a longitudinal direction. Value of P/(r·t) is not less than 4.8 and not more than 32, where P (atm) is pressure of xenon gas filled into the ceramic luminous tube, r (mm) is an inner diameter of the luminous portion of the ceramic luminous tube, and t (mm) is thickness of the luminous portion of the ceramic luminous tube.

Abstract: A vehicle headlamp including a discharge bulb having a ceramic light emitting tube, the light emitting tube having opposed electrodes and being filled with a light emitting substance; and a reflector, which controls a reflection of a light emitted from the light emitting tube. A cross-sectional shape of the light emitting tube is longer in a lateral direction than in a vertical direction.

Abstract: This invention relates to an optical fiber for long period grating (LPG), LPG components, and manufacturing method of LPG used as a mode coupler, an optical filter, etc. The optical fiber for LPG comprises a core layer, a first cladding layer that surrounds said core layer and transmits the cladding modes, and a second cladding layer that surrounds said first cladding layer and confines the optical signal of the cladding mode within said first cladding layer. The LPG component comprises an optical fiber for LPG, a coating reinforcement to cover and reinforce said optical fiber for LPG. The manufacturing method of LPG comprises a step of preparation of an optical fiber, a step of constructing the LPG on a predetermined region in said core of said optical fiber by irradiating laser light on said region over a predetermined period corresponding to the LPG, on the predetermined part of said optical fiber, and a step which covers and reinforces said grating region.

Abstract: An automotive discharge bulb having a light emitting tube includes a ceramic tube with paired electrodes oppositely placed, and contains a light emitting material and starting rare gas. A transversal section of the ceramic tube is longitudinally elongated. In the ceramic tube having a longitudinally elongated transversal section, an arc generated into an upwardly convex shape and the tube wall do not make contact.

Abstract: A discharge bulb is equipped with a discharge light emitting chamber tube in which discharge electrodes are provided face to face and a luminescent material is filled at the center of the ceramic tube in longitudinal direction. A metallic pipe is jointed into the pore of a tube end communicating with the discharge light emitting chamber. The rear end of an electrode rod inserted into the pipe with its tip protruding into the discharge light emitting chamber to constitute an electrode is jointed to the protruding tip of the pipe. A constricted part is arranged in the part between the tube center corresponding to the discharge light emitting chamber of the ceramic tube and the tube end. The thickness of the tube wall of the tube end is augmented to enhance the thermal shock resistance of the tube end.

Abstract: A vehicle headlamp including a discharge bulb having a ceramic light emitting tube, the light emitting tube having opposed electrodes and being filled with a light emitting substance; and a reflector, which controls a reflection of a light emitted from the light emitting tube. A cross-sectional shape of the light emitting tube is longer in a lateral direction than in a vertical direction.

Abstract: This invention relates to an optical fiber for long period grating (LPG), LPG components, and manufacturing method of LPG used as a mode coupler, an optical filter, etc. The optical fiber for LPG comprises a core layer, a first cladding layer that surrounds said core layer and transmits the cladding modes, and a second cladding layer that surrounds said first cladding layer and confines the optical signal of the cladding mode within said first cladding layer. The LPG component comprises an optical fiber for LPG, a coating reinforcement to cover and reinforce said optical fiber for LPG. The manufacturing method of LPG comprises a step of preparation of an optical fiber, a step of constructing the LPG on a predetermined region in said core of said optical fiber by irradiating laser light on said region over a predetermined period corresponding to the LPG, on the predetermined part of said optical fiber, and a step which covers and reinforces said grating region.

Abstract: In a discharge lamp device, the arc tube body is configured by welding and integrating shroud glass with an arc tube so as to enclose a discharging portion, and a rearward elongating portion of the arc tube that elongates in the rear of the shroud glass is inserted and held into an opening of an insulating plug which is made of synthetic resin. A UV blocking film is formed on the outer surface of the rearward elongating portion of the arc tube. UV components of leakage light from the rearward elongating portion are cut off, and the amount of ultraviolet rays to which the resin layer in the opening is exposed is reduced. The UV blocking film is in the opening, and hence cannot be seen through a front lens.

Abstract: An automotive discharge bulb having a light emitting tube includes a ceramic tube with paired electrodes oppositely placed, and contains a light emitting material and starting rare gas. A transversal section of the ceramic tube is longitudinally elongated. Because the capacity of an enclosed space of the ceramic tube is small, after discharging begins, the enclosed space temperature increases. Consequently, the ceramic tube has a good luminous flux rising characteristic. Because of the small surface area of the ceramic tube, the load imposed on the wall surface increases. Consequently, the ceramic tube has good luminous efficiency. In the ceramic tube having a longitudinally elongated transversal section, an arc generated into an upwardly convex shape and the tube wall do not make contact. Thermal shock resistance required of the ceramic tube is alleviated, durability is enhanced, and the ceramic tube is made of a ceramic material hitherto unusable.

Abstract: In a discharge bulb, an arc tube is fixed and held by an insulating base in the rear side such that the arc tube elongates forward. In the arc tube, an enclosed space is formed by sealing both ends of a straight cylindrical ceramic light emitting tube, electrodes are opposingly disposed therein, and the enclosed space is filled with a light emitting substance and starting rare gas. A light blocking film is disposed in part of a glass shroud surrounding the arc tube that corresponds to a sealed rear portion. To design effective reflecting surfaces, a rectangular light source image is projected onto a luminous distribution screen. Particularly, an upper end portion close to a horizontal cutoff line in the rectangular light source image projected in the vertical direction is clear. Even when the radially projected light source image approaches the elbow portion, a glare-free luminous distribution is formed.

Abstract: The invention is an arc tube for a discharge bulb in which both ends of a light emitting tube inserting electrode bars respectively are sealed and a closed space having the electrodes opposed to each other and filled with a light emitting substance together with a rare gas for starting is provided in the light emitting tube, the light emitting tube is constituted by translucent ceramics having an excellent heat resistance and durability which is formed almost cylindrically and a ratio d/L of an outside diameter d to a whole length L is set to range from 0.2 to 0.5, thereby reducing a size. Moreover, the parallel ray transmittance of the light emitting tube is set to be 20% or less and the whole ray transmittance of the light emitting tube 12 is set to be 85% or more. Consequently, the whole light emitting tube uniformly emits a light so that a bar-shaped light emitting section having neither a luminance unevenness nor a color unevenness is obtained.

Abstract: In a discharge bulb having an arc tube formed with pinch seal portions on both ends of a sealed glass bulb that is a light-emitting discharge section, infrared transmitting films for blocking visible light and transmitting infrared light are applied to at least the pinch seal portions of the arc tube to prevent visible light from exiting the pinch seal portions and to suppress generation of glare. Infrared light from the pinch seal portions can pass through the infrared transmitting films, which prevents accumulation of heat in the arc tube (pinch seal portions and sealed glass bulb), thereby preventing the temperature of the arc tube from increasing excessively.

Abstract: A lamp unit for emitting near-infrared light by electric discharge, has: a hollow discharge tube; a cesium halide enclosed in the hollow of the discharge tube; a near-infrared penetration filter covering around the discharge tube. The cesium halide may include at least one of cesium iodide and cesium bromide. Also, an indium halide and thallium halide may further be enclosed in the hollow discharge tube.

Abstract: The present invention provides an optical demultiplexer module capable of narrowing the interval between wavelengths of divided light. The optical demultiplexer module is provided with an optical circulator (2) or a non-reciprocal optical branching device, the first and second optical waveguides (3) and (4) connected to the optical circulator or non-reciprocal optical branching device, and the second arrayed waveguide diffraction grating (6) connected to the second optical waveguide (4) and having a plurality of emitting ports (6a) through (6h). The first optical waveguide (3) has a plurality of filters (3a) through (3i) which reflects light of a specified wavelength to the second optical waveguide (4) via the optical circulator (2) or non-reciprocal optical branching device. In the second arrayed waveguide diffraction grating (6), the center wavelengths of light emitted from a plurality of emitting ports differ by an appointed frequency in terms of frequency.