JP2011113791A - Metal halide lamp, ultraviolet irradiation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To aim at improvement of light-emission efficiency in a wavelength region of 350 to 380 nm by dissolving a part with low temperature distribution at both end parts of a metal halide lamp in a length direction. <P>SOLUTION: An electrodeless metal halide lamp 100 is structured by forming a discharge space 13 with a nearly cylindrical shape arc tube 11 of quartz glass made, in which at least rare gas, mercury as a discharge medium, and a discharge media such as iron are sealed. The metal halide lamp 100 makes iron as a discharge medium emit ultraviolet rays of 350 to 380 nm with by microwaves radiated from a magnetron. At sealing parts 121, 122 for forming the discharge space 13 in the arc tube 11, inorganic heat insulating films 151, 152 are formed in a range which does not infringe an effective light-emitting length of the arc tube 11. With this, light-emission efficiency can be improved through prevention of generation of the coldest-point temperature due to a valley part of a standing wave position at either end of the arc tube 11 of the microwaves. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrodeless metal halide lamp that excites with a microwave and emits ultraviolet rays, and an ultraviolet irradiation device using the lamp.

  In conventional metal halide lamps, the heat insulation film provided on the outer surface of the tube wall in the vicinity of the electrode opposed to the inside of the arc tube has a discharge space so that the coldest spot temperature at the time of lighting is closer to the center side than near both ends of the discharge space. A heat retaining means for retaining the vicinity of both ends of the is formed. (For example, Patent Document 1)

JP 2001-338610 A

  The technique of Patent Document 1 described above shows strong light emission by iron at a wavelength of 350 to 380 nm. However, when a microwave-fed electrodeless lamp is used as a metal halide lamp, the metal halide lamp is a microwave standing wave. Since discharge formation is performed, the coldest part occurs in the valley portion of the standing wave, and there is a problem that the luminous efficiency of iron decreases in the low temperature portion.

  An object of the present invention is to provide a microwave-fed electrodeless metal halide lamp capable of obtaining high luminous efficiency at 350 nm to 380 nm and an ultraviolet irradiation device using the lamp.

  In order to solve the above-described problems, the metal halide lamp of the present invention forms a discharge space with a substantially cylindrical quartz glass arc tube, and a discharge medium such as at least a rare gas, mercury or iron is contained in the discharge space. In a metal halide lamp in which a discharge is generated by microwaves emitted from a magnetron in an electrodeless lamp configured to be sealed, at least one arc tube sealing portion that does not infringe on the effective luminous length of the arc tube has heat resistance. It is characterized in that a heat insulating film excellent in the above is formed.

  An ultraviolet irradiation device according to the present invention comprises: a metal halide lamp according to claim 1 that emits ultraviolet light in which a discharge medium is enclosed; a lamp house that houses the metal halide lamp and is capable of irradiating ultraviolet light to the outside; In order to limit the irradiation area of the ultraviolet rays irradiated from the lamp house, the apparatus includes an ultraviolet cut filter installed below the ultraviolet irradiation surface.

  According to this invention, the inorganic heat insulating film having excellent heat resistance is formed on the end sealing portion that becomes the valley of the standing wave, and the temperature of the coldest portion is increased, thereby increasing the luminous efficiency of iron. The illuminance can be improved.

It is a perspective view for demonstrating one Embodiment regarding the metal halide lamp of this invention. It is a front view of FIG. It is explanatory drawing for demonstrating the standing wave of the microwave in an electrodeless lamp. It is explanatory drawing for demonstrating the spectral distribution which lighted this invention and the conventional lamp on the same conditions. It is explanatory drawing for demonstrating this invention and the conventional light emission ratio in 350-380 nm. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a system configuration diagram for explaining an embodiment relating to an ultraviolet irradiation device of the present invention. It is sectional drawing of the Ia-Ib line | wire of FIG.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 and FIG. 2 are perspective views and FIG. 2 is a front view of FIG. 1 for explaining an embodiment relating to a metal halide lamp of the present invention.

  1 and 2, reference numeral 100 denotes an electrodeless metal halide lamp, and 11 of the metal halide lamp 100 is made of quartz glass that transmits ultraviolet light, for example, a length of 140 mm, a tube diameter φ of 11 mm, and a wall thickness. It is a cylindrical arc tube whose m is about 1 mm. Since both ends of the arc tube 11 are heated to form the sealing portions 121 and 122, a discharge space 13 having an emission length of about 138 mm is formed.

  Further, in the discharge space 13 of the arc tube 11, an argon gas of 60 torr and a discharge medium such as mercury or iron are enclosed. In the sealing portions 121 and 122 of the arc tube 11, rod-like support portions 141 and 142 that support the arc tube 11 are integrally formed in a state of being melted with the same material as the arc tube 11.

  When the metal halide lamp 100 is irradiated with microwaves, the metal halide lamp 100 can emit light strongly at a wavelength of 350 to 380 nm of iron that is a discharge medium sealed in the discharge space 13.

  Here, a standing wave in an electrodeless lamp that emits light by being irradiated with microwaves will be described with reference to FIG.

  As shown by broken lines in FIG. 3, microwave standing wave valleys Va to Vc are generated at both ends and the center of the metal halide lamp 100 in the longitudinal direction. In each portion of the standing wave valleys Va to Vc, the electromagnetic energy is lower than that of the peak portions Ma and Mb, and therefore the inevitably generated temperature is also low.

  Again, in FIGS. 1 and 2, among the Va to Vc shown in FIG. 3, which are the microwave standing wave valleys, the coldest part is at the positions of the standing wave valleys Va and Vc of the metal halide lamp 100. Thermal insulation films 151 and 152 are formed on the arc tube 11 of the sealing portions 121 and 122. The heat insulating films 151 and 152 have excellent heat resistance and do not reflect microwaves within a range that does not infringe on the effective light emission length, specifically, in the region A that is about 5% of the arc tube length from the sealing portions 121 and 122, respectively. It is formed using an inorganic coating material mainly composed of silica, phosphoric acid, and zirconium oxide.

  As an example of a specific material of the heat-resistant inorganic coating used for the heat retaining films 151 and 152, Bond X (trade name) manufactured by Nissan Chemical Industries, Ltd. can be given.

  FIG. 4 is an explanatory diagram for explaining the spectral distribution when a lamp in which the heat retaining films 151 and 152 of the present invention are formed and a lamp in which a conventional heat retaining film is not formed are lit under the same conditions.

  The metal halide lamp 100 of the present invention in which the heat insulating films 151 and 152 shown by the solid line in FIG. 4 are formed is a metal halide having a high luminous efficiency in the wavelength region of 350 nm to 380 nm as compared with the conventional metal halide lamp without the heat insulating film shown by the broken line. A lamp can be realized.

  FIG. 5 is for explaining the light emission ratio of the present invention and the prior art. That is, in the wavelength range of 350 nm to 380 nm, the metal halide lamp of the present invention shows an improvement in the light emission distribution of about 28%.

  In this embodiment, the evaporation amount of iron is increased by raising the coldest part temperature to the sealing part which is a part of the valley of the standing wave formed by microwaves in the electrodeless metal halide lamp with microwave feed. In the wavelength region of 350 nm to 380 nm, the luminous efficiency can be improved as compared with the conventional case.

  In the embodiment of the metal halide lamp of the present invention described above, the heat insulating film is formed on the sealing portions 121 and 122 at both ends of the metal halide lamp 100. However, the heat insulating film is formed on at least one sealing portion. It doesn't matter. In this case, although the luminous efficiency improvement is inferior compared with the case where it is formed on both sides, the luminous efficiency can be improved as compared with the case where the heat insulating film is not formed.

  Further, it is conceivable to form a heat insulating film at the intermediate portion in the longitudinal direction of the arc tube 11 where the standing wave of the microwave is generated, and to raise the temperature here. However, if a heat insulating film is formed at the intermediate portion, the heat insulating film is formed. Therefore, the portion corresponding to the valley of the standing wave in the sealing portion of the arc tube 11 is used.

  6 and 7 are diagrams for explaining a lighting device for lighting an electrodeless metal halide lamp according to the present invention. FIG. 6 is a system configuration diagram, and FIG. 7 is a sectional view taken along line Ia-Ib in FIG.

  61 of the ultraviolet irradiation device 200 is a lamp house made of, for example, stainless steel having a function of shielding microwaves, and this lamp house 61 is not provided with an electrode at the lower central portion thereof, which has been described with reference to FIGS. The metal halide lamp 100 of the invention is attached to a part of the side surface of the lamp house 61.

  Reference numeral 62 denotes a magnetron that generates a microwave of 2.45 GHz, for example, and power is supplied to the magnetron 62 from a power source 63. Reference numeral 64 denotes a waveguide that transmits the microwave generated by the magnetron 62 from the antenna 65 and transmits the microwave to the metal halide lamp 100.

  An air inlet 66 is provided on the upper surface of the lamp house 11 so that air as a cooling medium blown from the blower 67 is taken into the lamp house 61. A duct (not shown) is provided between the blower 67 and the intake port 66 so as to take in the wind sent from the blower 67.

  On the back side of the metal halide lamp 100, a reflecting plate 68 for condensing or diffusing irradiated ultraviolet light is installed. An RF screen 69 constituting an irradiation window is provided in a part of the lamp house 61 on the front surface of the reflection plate 68. The RF screen 69 is made of metal and has an opening, blocks microwaves, and allows ultraviolet light and air to pass through.

  The RF screen 69 is formed, for example, by knitting a metal wire into a mesh shape or by forming a metal plate in a mesh shape by punching processing. The opposite surface of the RF screen 69 facing the metal halide lamp 100 is an ultraviolet irradiation surface.

  In this way, the metal halide lamp 100 excited by the microwave of the magnetron 62 emits ultraviolet light and can irradiate an irradiation object (not shown) via the RF screen 69.

  In this embodiment, by increasing the temperature of the portion having a low temperature distribution at both ends in the longitudinal direction of the metal halide lamp 100, the emission efficiency in the wavelength region of 350 to 380 nm emitted from the metal halide lamp 100 is improved. Irradiation can be realized.

DESCRIPTION OF SYMBOLS 100 Metal halide lamp 11 Light emission tube 121,122 Sealing part 13 Discharge space 141,142 Support part 151,152 Thermal insulation film 200 Ultraviolet irradiation apparatus 61 Lamp house 62 Magnetron 63 Power supply 64 Waveguide 65 Antenna 66 Inlet 67 Blower 68 Reflector 69 RF screen

Claims (3)

A discharge space is formed by a substantially cylindrical quartz glass arc tube, and at least a rare gas, mercury, and a discharge medium such as iron are enclosed in the discharge space, and is emitted from a magnetron to an electrodeless lamp. In metal halide lamps where discharge is generated by microwaves,
A metal halide lamp characterized in that a heat insulating film having excellent heat resistance is formed on a sealing portion of at least one arc tube that does not infringe on the effective luminous length of the arc tube.   2. The metal halide lamp according to claim 1, wherein the heat insulating film is formed of a heat resistant inorganic coating agent that does not reflect microwaves. The metal halide lamp according to claim 1 or 2, which emits ultraviolet light in which a discharge medium is enclosed;
A lamp house that houses the metal halide lamp and that can radiate ultraviolet rays to the outside;
An ultraviolet irradiation device comprising: an ultraviolet cut filter installed under the ultraviolet irradiation surface in order to limit an irradiation region of ultraviolet rays irradiated from the lamp house.

Images