JP4872454B2 - Electromagnetic excitation light source device - Google Patents

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 lamp of this system, the discharge concentrator concentrates the electric field in the discharge space and does not have a sealing portion that leads to a different member different from the discharge space to the outside, so that the burst pressure resistance of the lamp can be increased. It is said.

  FIG. 1 shows an example of a discharge concentrator light source device. A lamp 1 having a reflection mirror 7 is disposed in a microwave resonance chamber 9, and electric power is supplied to the discharge concentrators 3, 3 ′ in the lamp 1 by a microwave from the microwave source 6 by radio wave resonance, and the discharge space 1A. Among them, the electric field is concentrated by the discharge concentrators 3 and 3 ', and 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 of confining a microwave in a cavity resonator and lighting a lamp inside is widely known. On the other hand, the microwave launcher is a technique for giving a propagating microwave to the lamp with a directivity from a certain direction and lighting the lamp. In particular, by providing an antenna member inside the lamp, microwaves can be directly input into the discharge space in the 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. For example, glass is filled between the outer conductor and the inner conductor.

  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 lamp can be lit with a low-wattage microwave. .

FIG. 2A shows an example of a light source device 300 including the microwave launcher 10. The microwave from the microwave source 6 propagates through the waveguide 11, reaches the microwave launcher 10, and the thin tube portion 21 b of the foil seal type lamp 21 is inserted into 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.
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 has found that the concentrator type lamp of Patent Document 1 is superior in the bursting pressure resistance of the lamp as compared with the foil seal type lamp, and this type of lamp becomes a compact device that does not require a microwave cavity resonator. A light source device combined with the microwave launcher type device of Non-Patent Document 1 was manufactured, and detailed examination was performed by a lighting experiment. FIG. 2B shows a state in which the concentrator type lamp 1 is arranged in the microwave launcher 10.

  In the lighting experiment, the antenna member 30, 30 'in the lamp 1 is displaced while the lamp is lit while the light is turned on and off repeatedly, and the distance between the antenna members 30, 30' is changed. It has been found that there is a problem that the lamp light quantity varies.

  In the worst case, the antenna member arranged on the lower side of the lamp comes out against the gravity, contacts the upper antenna member, and is welded, so that it may not function as a lamp.

  As a result of intensive studies by the present inventor, the following is considered as the cause of the displacement of the antenna member. FIG. 3 is a diagram for explaining displacement of the positions of the antenna members 30 and 30 ′ of the lamp 1. When the antenna members 30 and 30 ′ are disposed inside the lamp 1, the discharge vessel material of the narrow tube portion 50 b around the antenna member 30 is melted to surround the antenna members 30 and 30 ′ with the discharge vessel material.

  For example, when the discharge vessel material is quartz glass, the antenna member inside the lamp is fixed by baking quartz glass around the antenna member. Reference numeral 50a denotes a bulging portion. The antenna members 30 and 30 'are made of, for example, tungsten. At this time, a gap is always provided between the antenna members 30 and 30 'and the discharge vessel material of the narrow tube portion 50b. Because the antenna members 30, 30 'and the discharge vessel material usually have different coefficients of thermal expansion, when they are completely brought into contact with each other, the antenna member 30, 30' This is because, for example, when the discharge vessel material is quartz glass, cracks occur in the quartz glass due to the difference in thermal stress due to the difference in thermal expansion coefficient between 30 'and the discharge vessel material.

  Therefore, in order to prevent this, in the case where the discharge vessel material is quartz glass, providing a slight gap between both the antenna member and the quartz glass without causing excessive burning of the thin tube portion 50b from the outside does not cause cracks. It is a simple and effective method.

In order to obtain an arbitrary light emission in this state, an inclusion fs such as mercury, a metal halide or sulfur is contained (FIG. 3A). As shown in FIG. 2B, the narrow tube portion 50b of the lamp 1 is inserted into the microwave launcher 10 of the light source device 300, and once lit, the enclosed material in the discharge vessel becomes steam. It is expected that the inclusion fs ′ enters the gaps s and s ₀ between the antenna member and the discharge vessel material when the inclusion is condensed and returns to the liquid state during cooling after the lighting (FIG. 3B).

When the light is turned on again, when the liquid-state or solid-state inclusion condensed in the gap s ₀ becomes the inclusion vapor fg again, the pressure pushes and moves the antenna member (the direction of the force varies). However, for example, the direction of the arrow in the figure) is expected to occur, and it is considered that the antenna member moves by the force.

  The reason why the encapsulated material becomes vapor again is thought to be that the encapsulated gas present in the gap between the antenna member and the quartz glass is discharged by microwave excitation, and the temperature of the gap increases. When the antenna member 30 comes out of the narrow tube portion 50b, the inclusions are accumulated in the gap below the antenna member 30 as shown in FIG. 3C, and are pushed up by the vapor pressure of the inclusions at the time of relighting. This is presumed to be due to this.

  As another technique for suppressing the movement of the antenna member, as described in JP-A-11-260315, in the technique of fixing the electrode core rod to the glass member, the gap between the electrode core rod and the glass member is made of powder such as tungsten. A technique of firing in a state filled with is also conceivable, and even when the technique described in the publication is applied to the gap between the antenna member 30 and the discharge vessel material, the gap is not filled with powder such as tungsten, Since the gap always exists, the above-described problem occurs.

  Further, there is a technique in which an antenna member, for example, tungsten is plated with a metal that is difficult to wet with glass, for example, rhodium or rhenium, in order to suppress cracks when the thin tube portion is baked. Even when this technology is applied, since there is a difference in the coefficient of thermal expansion between the antenna material and the discharge vessel material, there is always a gap that allows the liquid inclusion to flow. Such a problem will occur.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electromagnetic wave excitation light source device including a discharge lamp that is stably lit without the antenna member being displaced or the antenna member being pulled out of the thin tube portion during lamp lighting.

In order to solve the above problems, the present invention has the following configuration. That is, the invention described in claim 1 is made of a translucent non-conductive material, and has a bulging portion and a thin tube portion connected to the bulging portion, and without protruding outside the discharge vessel, An antenna member made of a metal or a dielectric, which is supported by a narrow tube portion and has a tip portion facing the discharge space of the bulging portion, which acts to concentrate and strengthen an electric field in the discharge space, and has a light emitting substance in the discharge vessel An electromagnetic wave excitation light source device comprising: a discharge lamp enclosing a discharge lamp; and an electromagnetic wave supply means for supplying an electromagnetic wave to the antenna member, wherein the electromagnetic wave supply means includes an electromagnetic wave radiation portion that emits directional radiation, The antenna member is an electromagnetic wave excitation light source device in which a rear end portion located in the narrow tube portion has a sharp shape .

The invention according to claim 2 is made of a translucent non-conductive material, and has a bulging portion and a thin tube portion connected to the bulging portion, and without protruding outside the discharge vessel, An antenna member made of a metal or a dielectric, which is supported by a narrow tube portion and has a tip portion facing the discharge space of the bulging portion, which acts to concentrate and strengthen an electric field in the discharge space, and has a light emitting substance in the discharge vessel An electromagnetic wave excitation light source device comprising: a discharge lamp enclosing a discharge lamp; and an electromagnetic wave supply means for supplying an electromagnetic wave to the antenna member, wherein the electromagnetic wave supply means includes an electromagnetic wave radiation portion that emits directional radiation,
2. The electromagnetic wave excitation light source device according to claim 1, wherein a cutout is provided in a peripheral surface of a portion of the antenna member located in the narrow tube portion, and a discharge container material constituting the narrow tube portion enters the cut and the antenna member is fixed. It is what.

According to the present invention, if the rear end portion of the antenna member located in the narrow tube portion has a sharp shape, the gap can be reduced as much as possible. Even if the encapsulated material vaporized during lighting reaches the discharge space through the gap between the periphery of the antenna member and the thin tube portion, the antenna member can be prevented from being displaced.

And it can suppress that an antenna member displaces by providing a notch in the surrounding surface of the part located in a thin tube part of an antenna member, and the inner wall face of a thin tube part entering the notch .

  FIG. 4 shows a schematic diagram of an embodiment of the present invention. The light source device 100 is a device using a microwave launcher 10 that is an electromagnetic wave radiation portion 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. The outer circumference of the outer conductor 10b is uneven for heat dissipation. A discharge vessel 50 made of a translucent non-conductive material and having a bulging portion 50a and a thin tube portion 50b connected thereto, and a tip portion supported by the thin tube portion 50b without protruding outside the discharge vessel 50 30a, 30'a facing the discharge space of the bulging portion, having an action of concentrating and strengthening the electric field in the discharge space, comprising antenna members 30, 30 'made of metal or dielectric, and having a luminescent material in the discharge vessel And an electromagnetic wave supply means 90 for supplying an electromagnetic wave for exciting discharge to the antenna member from the outside of the discharge lamp.

  Part X1 and X2 which bear the displacement suppression function of the antenna member which suppresses the displacement of the position of the antenna member are provided. The antenna member preferably has a diameter of 1 mm or more in order to avoid a decrease in arc temperature due to heat conduction from the discharge arc plasma and in order to avoid red heat and evaporation of the antenna member itself. On the other hand, if the diameter is too thin, the antenna tip tends to be deformed and melted by the heat of the plasma during lighting, so that the diameter is preferably thicker than 0.1 mm for practical use.

  In the portions X1 and X2 that bear the function of suppressing the displacement of the antenna member, there is a sharpened portion at the rear end of the antenna portion as X1. X2 is a recess 30'b such as a notch and a surrounding thin tube 50'b. If the rear end of the antenna member opposite to the discharge space is flat, when the antenna member is burned with the discharge vessel material in a reduced pressure state, the rear end of the antenna member A conical space is created. Inclusions may accumulate in this area.

  Patent Document 1 proposes a technique for suppressing the occurrence of corona discharge by concentrating the electric field intensity by making the rear end curved as a shape of the discharge concentrator, narrowing the gap, and concentrating the electric field strength. However, in the microwave launcher type light source device, at least the rear end portion of the antenna member on the side inserted into the inner conductor of the launcher is sharpened so that the electric field strength is further concentrated on the tip of the antenna on the discharge space side.

  This is because if the tip of the antenna member is a curved surface, a gap is easily formed when the glass is baked. Ideally, if the shape of the antenna is sharpened along the gap that is created when it is baked, the gap around which the encapsulated material wraps can be almost eliminated.

  The sharpening effect not only narrows the space where the inclusions of the antenna member accumulate, but also increases the force that pushes out the antenna even when the inclusions accumulate there and force is applied to the antenna with the vapor pressure during lighting. Also has the advantage of being dispersible.

  By providing a recess 30b such as a notch on the peripheral surface of the antenna member 30 and burning the discharge container material in that portion, it is possible to prevent the antenna member 30 from moving due to the pressure of the discharge substance during lighting.

  Naturally, even in the recess 30b, a gap is provided between the antenna member 30 and the discharge vessel material so as not to cause excessive cracking. As shown in FIG. 5, the shape of the concave portion 30 b that serves as a part for suppressing the displacement of the antenna member includes a cut K (FIG. 5 (a)) and a circular groove E (FIG. 5 (b)) over the circumference. And a spiral groove R (FIG. 5C).

  Further, as the shape of the other antenna member 30, as shown in FIG. 6, there is a protruding portion 31 as a portion responsible for a displacement suppressing function (FIG. 6A), or a shape that increases in diameter as the distance from the discharge space increases. That is, it may be one with a taper T (FIG. 6B). In this case, the antenna member 30 with the taper T itself has a displacement suppressing function.

  Next, an example is shown in which the entire antenna member is covered with the discharge vessel constituent material, and the covered antenna member is welded and fixed by a thin tube portion. The whole antenna member 30 is covered with a covering material 60 of a discharge vessel constituting material, and the covered antenna member is welded and fixed by a thin tube portion.

  If the lamp is miniaturized and the diameter of the antenna member becomes extremely thin, for example, about φ0.3 mm, it will be difficult to form a recess in the antenna member, which will increase the work process and increase the cost. It is preferable to cover the whole with the discharge vessel constituent material.

  FIG. 7 shows the antenna member covered with the same material as the discharge vessel material in advance. For example, when the discharge vessel material is quartz glass, the antenna member 30 is disposed in the quartz glass tube 60A as shown in FIG. By baking with a hydrogen burner, the quartz glass 60A contracts due to reduced pressure, so that the periphery of the antenna member 30 can be covered with the quartz glass 60A. Excess quartz glass is removed. Also at this time, a gap is provided between the antenna member 30 and the quartz glass 60A by adjusting the degree of burning. If discharge occurs in this gap and causes a problem, an insulating gas such as SF6 (sulfur hexafluoride) can be sealed to prevent it.

  Then, the antenna member 30 covered with the quartz glass 60A is inserted into the discharge vessel, and the thin tube portion of the discharge vessel is baked from the outside with an oxyhydrogen burner under reduced pressure conditions. The container material is integrated and the antenna member is fixed. In this way, the pressure of the encapsulated object during lighting and the gap around the antenna can be made completely independent, so that the encased object is wrapped around by repeatedly turning on and off the lamp, and as a result, the antenna member comes off during lighting. It will not be.

  Even when the antenna member is covered with a dielectric material such as glass, the electromagnetic wave-excited discharge lamp can inject electromagnetic energy into the arc tube so that the lamp can be turned on.

  When the antenna member is covered with the discharge container material, the gap into which the inclusion enters can be completely removed by completely joining at the base portion of the inner wall of the arc tube. In this case, it is possible to prevent the antenna member covered with the discharge vessel material from being displaced by the internal pressure during lighting, and also has the advantage that the inner volume of the arc tube can be made constant. Therefore, there is an advantage that the non-evaporated filling material can be reduced as much as possible. A coating thickness in the range of 0.3 mm to 2 mm is appropriate because the workability is easy in production.

  Even if the antenna member is not completely covered with the discharge vessel material, the antenna member may come off at the time of lighting by winding glass only on the portion located on the discharge space side and welding it to the discharge vessel at the glass winding portion. There is no longer to do.

  The antenna member 30 is repeatedly turned on and off by connecting a metal foil 80 to the rear end portion of the antenna member 30 of the lamp 1 located in the narrow tube portion and welding and fixing the discharge vessel material in the narrow tube portion 1B. Can be suppressed. s1 is a gap. The metal foil 80 is preferably made of molybdenum metal when the discharge vessel material is quartz glass. The form is shown in FIG.

  The antenna member may be not only a metal but also a dielectric, and preferably a material having a high relative dielectric constant and low dielectric loss. Specific examples include silica, alumina, zirconia, and K140 (manufactured by Kyocera Corporation), which is a high dielectric material having a relative dielectric constant of about 140.

  In particular, when the encapsulant is sulfur, quartz glass is used as the discharge vessel, and zirconia is used as the antenna member when it is exposed to the discharge space.

  Similarly, in the sealed gas, one or more kinds of rare gases such as xenon and argon, and any inert gas can be appropriately selected according to the desired wavelength and function.

  Next, specific examples will be described.

FIG. 10 shows a lamp applied to the present invention. In FIG. 10, the discharge vessel 50 of the lamp 1 is made of transparent quartz glass, the inner diameter of the lamp is φ3.5 mm, the length in the major axis direction inside the lamp is 7 mm, and the wall thickness. The distance between the antenna members is 1.5 mm and 4 mm.
The antenna member was made of tungsten having a diameter of 0.3 mm and a length of 8 mm, the sharp point was 0.5 mm, the cut width was 1 mm, and the depth was 0.15 mm. Mercury was 120 mg / cm ³ as a luminescent substance and argon was sealed at 13.3 kPa as a buffer gas. This lamp is incorporated in the device of FIG.
Microwave power with a frequency of 2.45 GHz was output from a solid state oscillator, and the lamp was lit with 50 W power.

As a result of repeatedly turning on and off for one hour, the conventional lamp has a problem that the antenna is displaced while two of the ten lamps are turned on at the beginning of lighting (continuous lighting time is within 100 hours). On the other hand, such an inconvenience did not occur in a lamp with a sharp antenna and a cut groove.
In addition, the lamp light quantity fluctuation caused by the displacement of the lighting antenna was examined. At this time, a lamp with a sharp antenna and a cut groove was designated as a lamp A, and the lighting result of the lamp A was used as a reference. Assuming that the lamp with only the groove cut is lamp B, lamp B was almost the same as lamp A. On the other hand, if the lamp with only the sharpened antenna is the lamp C, the lamp C is not at a level that causes a problem as compared with the lamp A and the lamp B, but there is a lamp that fluctuates slightly.

FIG. 11 also shows a lamp applied to the present invention. In FIG. 11, the discharge vessel 50 of the lamp 1 is made of transparent quartz glass, the inner diameter of the lamp is 3.5 mm, the length in the long axis direction inside the lamp is 7 mm, and the wall thickness. The distance between the antenna members is 1.5 mm and 4 mm. Tungsten with an antenna diameter of 0.3 mm and a length of 8 mm was covered with a covering material 60 made of transparent quartz glass, and the outer diameter was set to φ0.75 mm and inserted into the lamp.
Mercury was charged at 120 mg / cm ³ as a luminescent material, and argon was sealed at 13.3 kPa as a buffer gas. This lamp was incorporated in the apparatus shown in FIG. 4, microwave power having a frequency of 2.45 GHz was output from the solid state oscillator, and the lamp was turned on with power of 50 W.

  As a result of repeating the lighting and extinguishing for 1 hour, there was no problem of fluctuation of the light amount or displacement of the antenna.

  Regarding the frequency, the content of the present invention can be applied not only to the microwave but also to high frequency lighting of 13.56 MHz, for example. As for the input power, the case of 50 W is taken as an example in the above description, but the present invention can be applied to lighting with a power of several kW by appropriately selecting the size of the lamp.

An example of a discharge concentrator light source device is shown. 1 shows a light source device equipped with a microwave launcher. The figure explaining the displacement of the position of an antenna member is shown. The schematic about embodiment of this invention is shown. The shape of the recessed part used as the part which bears the displacement suppression function of an antenna member is shown. The shape of the protrusion used as a part which bears the displacement suppression function of an antenna member is shown. The example which covered the antenna member with the same material as the discharge vessel is shown. The manufacturing method and application example of the antenna member of FIG. 7 are shown. The example which connected metal foil to the rear end of the antenna member is shown. The lamp | ramp applied to the light source device of this invention is shown. The lamp | ramp applied to the light source device of this invention is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lamp 1A Discharge space 1B Narrow tube part 3, 3 'Discharge concentrator 3a, 3'a Tip part 6 Microwave source 7 Reflection mirror 8 Opening part 9 Microwave resonance chamber 10 Microwave launcher 11 Waveguide 13 Stub tuner 14 Movable plunger 21 Lamp 21b Narrow tube portion 30, 30 'Antenna member 30b Recess 31 Projection portion 50 Discharge vessel 50a Swelling portion 50b, 50'b Narrow tube portion 60 Glass tube 70 Reflecting mirror 80 Metal foil 90 Microwave source 100 Light source device 200 Light source device 300 Light source device ´
M inclusion

Claims (2)

A discharge vessel made of a light-transmitting non-conductive material and having a bulging portion and a thin tube portion connected to the bulging portion, and a tip portion bulging supported by the thin tube portion without protruding outside the discharge vessel A discharge lamp having an antenna member made of a metal or a dielectric that acts to concentrate and strengthen an electric field in the discharge space, facing the discharge space of the portion, and in which a luminescent material is sealed in the discharge vessel;
Electromagnetic wave supply means for supplying electromagnetic waves to the antenna member;
In an electromagnetic wave excitation light source device comprising:
The electromagnetic wave supply means includes an electromagnetic wave radiation portion that emits directional radiation,
The electromagnetic wave excitation light source device , wherein a rear end portion of the antenna member located in the narrow tube portion has a sharp shape . A discharge vessel made of a light-transmitting non-conductive material and having a bulging portion and a thin tube portion connected to the bulging portion, and a tip portion bulging supported by the thin tube portion without protruding outside the discharge vessel A discharge lamp having an antenna member made of a metal or a dielectric that acts to concentrate and strengthen an electric field in the discharge space, facing the discharge space of the portion, and in which a luminescent material is sealed in the discharge vessel;
Electromagnetic wave supply means for supplying electromagnetic waves to the antenna member;
In an electromagnetic wave excitation light source device comprising:
The electromagnetic wave supply means includes an electromagnetic wave radiation portion that emits directional radiation,
An electromagnetic wave excitation light source device characterized in that a cutout is provided on a peripheral surface of a portion of the antenna member located in the narrow tube portion, and a discharge vessel material constituting the narrow tube portion enters the cut and the antenna member is fixed .

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