JP2009099479A - Electromagnetic wave excitation light source device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic wave excitation light source device with a discharge lamp free from such a problem that a crack grows using a microcrack present in the interface with a glass burned in order to support an antenna member during lamp lighting as a starting point and a lump is not lit even when using the lamp having high mercury content. <P>SOLUTION: This electromagnetic wave excitation light source device comprises: a discharge vessel made of silica glass and having a bulged portion and a narrow tube part arranged continuously to it; an antenna member made of metallic material and supported by the narrow tube part without projecting from the discharge vessel while facing the tip to the discharge space of the bulged portion and acting to concentrate and intensify an electric field in the discharge space; a discharge lamp filled with mercury or metallic halide in the discharge vessel; and an electromagnetic wave supply means for supplying electromagnetic waves to the antenna member. The antenna member consists of a rod antenna tip projecting to the charge space and an antenna main part following the tip. The antenna main part is provided with a metallic foil part at least. The metallic foil part is attached firmly to the silica glass in the narrow tube part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a light source device that is lit by electromagnetic wave excitation, and more particularly, to a light source device that is lit by electromagnetic wave excitation from an electromagnetic wave supply means having an electromagnetic wave radiation part that emits directional radiation.

  Currently, liquid crystal projectors are used as presentation tools in conferences and exhibitions. As a high-intensity light source for the liquid crystal projector, an ultrahigh pressure mercury lamp is mainly used. However, since the ultra-high pressure mercury lamp sealed with a foil seal has a limit in the pressure resistance of the sealing portion, it is assumed that there will be a limit in the near future for higher brightness.

  Patent Document 1 proposes a discharge concentrator type light source device without a foil seal. According to the discharge lamp of this system, the discharge concentrator concentrates the electric field in the discharge space and does not have a sealing part that leads to a different member different from the discharge space. It is supposed to be possible.

  FIG. 6 shows an example of a discharge concentrator light source device. A discharge lamp 1 having a reflection mirror 7 is arranged in a microwave resonance chamber 9, and electric power is supplied to the discharge concentrators 3, 3 ′ in the discharge lamp 1 by the microwave from the microwave source 6 by the radio wave resonance action. In the space 1A, the electric field is concentrated by the discharge concentrators 3 and 3 ', the electric field is strengthened, and a high-luminance point light source appears between the two tip portions 3a and 3'a of the discharge concentrators 3 and 3'. Light is emitted from the opening 8 provided in the microwave resonance chamber 9.

  In this discharge concentrator type light source device 200, the members 3, 3 ′ called discharge concentrators have a function of concentrating the microwave electric field inside the discharge space. Are called antenna members.

  Further, in Non-Patent Document 1, as a new lamp emission excitation method using microwaves, a “microwave launcher” which is a microwave radiating unit that emits directional microwaves, is a coaxial type that emits microwaves. There has been proposed a light source device that is arranged to irradiate with microwaves by arranging an electrodeless lamp or a foil seal lamp with electrode at the tip of the waveguide.

  As a conventional microwave excitation technique, a technique for confining a microwave in a cavity resonator and lighting a discharge lamp therein is widely known. On the other hand, the microwave launcher is a technique for giving a propagating microwave to the discharge lamp with a directivity from a certain direction and lighting the discharge lamp. In particular, by providing an antenna member inside the discharge lamp, microwaves can be directly input into the discharge space in the discharge lamp. As a configuration of the microwave launcher, for example, an inner conductor and an outer conductor are arranged coaxially, a microwave is propagated therebetween, and a microwave is radiated from an end face thereof.

According to this method, compared to a discharge concentrator type light source device as disclosed in Patent Document 1, there is an advantage that a microwave cavity resonator is unnecessary and a discharge lamp can be lit with a low-wattage microwave. The
JP 2001-102005 M.Shido et al., Luminous efficacy of compact high-pressure metal-halide microwave discharge lamps, Proc.XXVIIth ICPIG, Eindhoven, the Netherland, 18-22 July (2005) Topic No.16

  The present inventor manufactured a light source device in which the concentrator lamp of Patent Document 1 is combined with the microwave launcher type device of Non-Patent Document 1 which is a compact device that does not require a microwave cavity resonator, and by a lighting experiment. Detailed examination was conducted. FIG. 2 shows a light source device 300 in which the concentrator type discharge lamp 1 is arranged in the microwave launcher 10. Reference numeral 13 denotes a stub tuner, and reference numeral 14 denotes a movable plunger. The microwave launcher 10 has an inner conductor 10a and an outer conductor 10b arranged in an axial shape, and a glass 10c is filled between the inner conductor 10a and the outer conductor 10b. As described above, in the present invention, the discharge concentrator is referred to as an antenna member.

The antenna member 30 is made of metal and has a structure in which the antenna member 30 is supported by a thin tube portion 50b made of quartz glass. However, when a high-intensity light source represented by a liquid crystal projector is used, the amount of mercury needs to be 150 mg / cm ³ or more. The lighting pressure at that time is 20 MPa or more. In the figure, reference numeral 50a denotes a bulging portion.
FIG. 4 is an enlarged view of the thin tube portion 50b. When this discharge lamp is turned on, mercury enters the entire periphery of the antenna member 30 and the glass member baked to support the antenna member 30 and the antenna member. It has been found that, starting from a microcrack existing at the interface, the crack grows toward the outside of the narrow tube portion, and eventually the discharge lamp is turned off. In FIG. 4, the portion where the microcrack enters is a portion where X marks are continuously added.

  This failure occurs in the same way even when a metal halide, for example, indium bromide InBr, is used, and it is seen that the same failure also occurs in a lamp under a condition where the operating pressure is about 2 MPa in order to obtain light emission in the visible region. It was issued.

  Therefore, the object of the present invention is to prevent microcracks present at the interface with the glass baked to support the antenna member during the operation of the discharge lamp even in the case of a discharge lamp containing a large amount of mercury or metal halide. It is an object of the present invention to provide an electromagnetic wave excitation light source device including a discharge lamp that does not cause a problem that a crack grows and a discharge lamp leaks and the discharge lamp does not light up.

In order to solve the above problems, the present invention has the following configuration.
The invention according to claim 1 is made of quartz glass, and has a bulging portion and a narrow tube portion connected thereto, and a tip portion supported by the narrow tube portion without protruding outside the discharge vessel. A discharge lamp comprising an antenna member made of a metal material facing the discharge space of the bulging portion and acting to concentrate and strengthen an electric field in the discharge space, wherein mercury or a metal halide is enclosed in the discharge vessel; In the electromagnetic wave excitation light source device comprising an electromagnetic wave supply means for supplying an electromagnetic wave to the antenna member, the antenna member comprises a rod-shaped antenna tip portion protruding into a discharge space and an antenna main portion following the tip portion, The antenna main portion includes at least a metal foil portion, and the metal foil portion is formed in close contact with quartz glass in the narrow tube portion.

  According to a second aspect of the present invention, there is provided the electromagnetic wave excitation light source device according to the first aspect, wherein a contour of the metal foil portion on the outer end side of the discharge lamp is curved.

  According to the present invention, the antenna main portion has at least a metal foil portion, and the metal foil portion is in close contact with the glass in the narrow tube portion, so that the antenna member is baked to support the antenna member during the discharge lamp lighting. It is possible to provide an electromagnetic wave excitation light source device including a discharge lamp that does not cause a problem that a crack grows from a minute crack existing at an interface with glass and the discharge lamp is not turned on.

  In addition, the contour on the outer edge side of the metal foil is curved, so that the microwave electric field is prevented from becoming locally strong, and the microwave energy is radiated from the outer edge of the metal foil to the atmosphere. Energy consumption is suppressed. In other words, microwave energy can be prevented from leaking out of the lamp.

  FIG. 3 shows an enlarged view of a portion of the discharge lamp including the antenna member 30 of the light source device 400 according to one embodiment of the present invention. The entire light source device 400 is the same as the light source device 300 shown in FIG. 2, and only the discharge lamp is different. That is, here, the discharge lamp 1 of FIG. 2 is a discharge lamp 60 having a different antenna member 30. The light source device 300 is a device using a microwave launcher 10 as an electromagnetic wave radiation unit that emits directional radiation, as described in Non-Patent Document 1.

  In the microwave launcher 10, an inner conductor 10a and an outer conductor 10b are coaxially arranged. Although not shown, the outer conductor 10b may have irregularities on the outer periphery for heat dissipation. The antenna member 30 includes rod-shaped antenna tip portions 30a and 30'a that protrude into the discharge space of the discharge lamp 60, and antenna main portions 30b and 30'b that follow the tip portions. The antenna main portions 30b and 30'b have a metal foil portion, and the metal foil portion is in airtight contact with the glass in the narrow tube portion.

  The main part of the antenna following the tip of the antenna is provided with a metal foil part, so that the area where the microcrack is generated in the close contact part between the antenna and the quartz glass located in the narrow tube part is reduced, and mercury enters the microcrack. Alternatively, since the amount of metal halide can be suppressed, propagation of cracks can be suppressed.

5 shows a state in which the contour e1 of the outer end side of the metal foil portion 30b ₁ is in the curve. Such a curvilinear shape prevents the microwave electric field from becoming locally strong, and suppresses energy consumption by radiating microwave energy from the outer edge of the metal foil into the atmosphere. It is done.

Further, by narrowing the width of the metal foil portion 30b _1, it is more preferable to Sosu the effects of the present invention to about the same extent as the antenna tip 30a. The reason for this is that when the antenna member composed of the antenna tip and the metal foil is inserted into the glass tube constituting the thin tube, the metal foil is reduced to the same width as the antenna tip. The inner diameter can be made thin in advance, and when the antenna member is melted and adhered to the glass from its periphery, the amount of movement of the antenna member up, down, left and right can be minimized, and the amount of heat shrinkage of the glass tube material can be reduced. Since less is required, glass melt adhesion can be completed in a short time. As a result, cracks generated in the portion where the rod-shaped portion of the antenna member contracts with glass are suppressed, which is even better.
The metal foil 80 is preferably made of molybdenum in order to obtain good adhesion when the discharge vessel material is quartz glass.
The length of the metal foil portion is longer than that of the rod-shaped portion at the tip of the antenna. In addition, it is preferable that the metal foil part exists up to the vicinity of the discharge space in the narrow tube part. In the vicinity of the discharge space, the metal foil portion is not directly exposed to the discharge space, but refers to the inside of the narrow tube portion that can support the rod-shaped member constituting the tip portion of the antenna member with a width separated.

FIG. 1 shows a discharge lamp 60 applied to the present invention. In FIG. 1, the discharge vessel 50 of the discharge lamp 60 is made of transparent quartz glass, the inside diameter of the discharge vessel is 3.5 mm, and the inside of the discharge vessel is in the long axis direction. The length is 7 mm and the wall thickness is 1.5 mm. The thin tube portion is also made of transparent quartz glass, and its length is 20 mm. The distance between the antenna members facing each other in the discharge space is 4 mm. The rod-shaped portion of the antenna tip 30a of the antenna member 30 has a diameter of 0.3 mm, using a tungsten length 8 mm, the antenna main portion metal foil portion 30b ₁ has a thickness 25μm is, width 2 mm, a length of 10mm molybdenum foil It was used. The metal foil portion 30b ₁ is a rod-shaped portion and the antenna main portion of the antenna tip 30a is secured by spot welding.
Mercury was sealed at 220 mg / cm ³ as a luminescent material, and argon was sealed at 13.3 kPa as a buffer gas.

  Ten discharge lamps were manufactured and incorporated in the apparatus equipped with the microwave launcher shown in FIG. 2, microwave power with a frequency of 2.45 GHz was output from a solid state oscillator, and the discharge lamp was turned on with power of 100 W. Of the ten, one discharge lamp was not damaged by the crack propagation from the minute cracks in the glass near the antenna member in the narrow tube portion. That is, although the microcrack has arisen in the area | region shown by N of FIG. 1, since the antenna main part has metal foil part and the metal foil part is closely_contact | adhered with glass within a thin tube part, discharge lamp lighting There is no problem that the crack grows and the discharge lamp is not turned off starting from a minute crack existing at the interface with the glass baked to support the antenna member.

For comparison, the antenna member (concentrator in Patent Document 1) that does not have a metal foil portion as disclosed in Patent Document 1 is used, and the rod-shaped portion of the antenna tip of the antenna member uses tungsten having a diameter of 0.3 mm and a length of 8 mm. 10 discharge lamps, in which mercury as the luminescent material is sealed at 220 mg / cm ³ and argon as the buffer gas is sealed at 13.3 kPa, are also incorporated into the apparatus shown in FIG. 2, and microwave power with a frequency of 2.45 GHz is generated from the solid-state oscillator. The discharge lamp was turned on with power of 100 W. As a result, discharge lamp breakage occurred due to the propagation of cracks in the narrow tube portion in six out of ten.

  In the present embodiment, the content of the present invention can be applied to high frequency lighting of 13.56 MHz, for example, in addition to the microwave. Regarding the input power, the case of 100 W is taken as an example in the above description, but lighting with power of the order of several kW is also possible by appropriately selecting the size of the discharge lamp.

In this embodiment, mercury is used as the luminescent species. However, in the present invention, the case where a metal halide is used as the luminescent species is also applicable. Indium bromide InBr, InBr ₃ , zinc iodide ZnI ₂ , there is such as zinc bromide ZnBr _2.

  In order to suppress the propagation of micro cracks, the position of the end of the metal foil part, which is the antenna main part of the antenna member, on the discharge space side end in the thin tube part ideally has the metal foil part to the position facing the discharge space. However, if the metal foil portion is exposed in the discharge space, problems such as evaporation of the metal foil due to heat from the plasma in the discharge space occur, so the metal foil portion is not exposed in the discharge space. The position of the end of the metal foil portion on the discharge space side is determined so as to appropriately secure a width for supporting the tip of the antenna member with the glass of the thin tube portion. For example, in a discharge lamp having a discharge vessel inner diameter of 3.5 mm and a length of 7 mm in the major axis direction inside the discharge vessel, it is about 2 mm.

The whole figure of the discharge lamp applied to this invention is shown. 1 shows a light source device equipped with a microwave launcher. 1 illustrates one embodiment of the present invention. The position of the micro crack in the discharge lamp applied to the conventional electromagnetic wave excitation light source device is shown. The detail of the antenna member of the discharge lamp which concerns on this invention is shown. An example of the conventional discharge concentrator type electromagnetic wave excitation light source device is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Discharge lamp 1A Discharge space 1B Narrow tube part 3, 3 'Discharge concentrator 3a, 3'a Tip part 6 Microwave source 9 Microwave resonance chamber 10 Microwave launcher 10a Inner conductor 10b Outer conductor 10c Glass 11 Waveguide 13 Stub tuner 14 Movable plunger 30, 30 'Antenna member 30a, 30'a Antenna tip 30b, 30'b Antenna main part 30b ₁ Metal foil part 30b ₂ Rod-like body part 50 Discharge vessel 50a Swelling part 50b, 50'b Narrow tube part 60 Discharge Lamp 200 Light source device 300 Light source device 400 Light source device

Claims (2)

A discharge vessel made of quartz glass and having a bulging portion and a thin tube portion connected thereto,
An antenna made of a metal material that is supported by the narrow tube portion without projecting to the outside of the discharge vessel and whose tip portion faces the discharge space of the bulging portion, and that acts to concentrate and strengthen the electric field in the discharge space. A discharge lamp comprising a member, wherein the discharge vessel encloses mercury or a metal halide;
In an electromagnetic wave excitation light source device comprising an electromagnetic wave supply means for supplying an electromagnetic wave to the antenna member,
The antenna member is composed of a rod-shaped antenna tip portion protruding into the discharge space and an antenna main portion following the tip portion,
The electromagnetic wave excitation light source device characterized in that the antenna main portion includes at least a metal foil portion, and the metal foil portion is in close contact with quartz glass in the narrow tube portion.   2. The electromagnetic wave excitation light source device according to claim 1, wherein a contour of the metal foil portion on an outer end side of the discharge lamp is curved.

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