JP5493101B2 - Microwave discharge lamp - Google Patents

Description

  The present invention relates to a microwave discharge lamp that emits light by microwaves, and more particularly to a structure of a discharge lamp in which a long discharge tube can be arranged.

  In a microwave discharge lamp, a discharge tube is disposed in a microwave resonator (cavity), and a microwave output from a microwave oscillator such as a magnetron is resonated in the resonator. A strong electric field is applied by the supply of microwave power, and the discharge gas becomes a plasma state and discharges light.

In order to improve the light emission efficiency of the microwave discharge lamp, various improvements have been attempted with respect to the structure of the resonator, the arrangement of the discharge tubes, the microwave supply method, and the like. For example, two coaxial conductors are arranged in the resonator, or the discharge tube is arranged while adjusting the distance from the opening of the resonator (see Patent Documents 1 and 2). In order to increase the power of the microwave, a plurality of magnetrons are connected to the resonator (see Patent Document 3).
JP-A-8-161911 JP 2004-355980 A Japanese Utility Model Publication No. 7-22455

  In industrial fields such as photolithography, sterilization treatment, and cleaning treatment, a light source device that irradiates light over a wide range is required as an irradiation object such as a liquid crystal device becomes larger. However, it is difficult to dispose a long discharge tube in the resonator from the viewpoint of enlargement of the resonator and cost, and the discharge tube is accommodated inside the resonator having a shield structure for preventing electromagnetic wave leakage. It is difficult to extract light efficiently outside. In particular, light cannot be extracted radially over the entire discharge tube.

  Accordingly, an object of the present invention is to provide a microwave discharge lamp capable of efficiently emitting light over a wide range.

  The microwave discharge lamp of the present invention is a lamp that emits light without using a microwave resonator, and includes at least one microwave oscillator that oscillates microwaves such as a magnetron, a discharge tube in which a discharge gas is sealed, And a tubular conductor surrounding the discharge tube along the tube axis direction.

  A discharge tube made of quartz glass, ceramics, or the like can be configured as a long discharge tube extending long along the tube axis direction. For example, a mixed gas of CO and Xe that emits vacuum ultraviolet light is used as a discharge gas. Enclosed. The tubular conductor has conductivity and is configured to cover the discharge tube.

  In the present invention, microwaves are supplied to the end of the discharge tube. When plasma is generated in the discharge tube by the supply of microwave power, since the plasma has conductivity, the plasma in the discharge tube and the tubular conductor function as an inner conductor and an outer conductor of the coaxial line, respectively.

  Therefore, when plasma is generated at the end of the discharge tube immediately after the start of discharge, the microwave propagates in the axial direction of the coaxial line, and the plasma extends in the axial direction of the tube along with the propagation of the microwave. As the microwave propagation and the plasma generation interact with each other, the plasma generation portion, that is, the area where discharge light is emitted, extends toward the other end of the discharge tube. The coaxial line is not limited to a line in which an inner conductor and an outer conductor having a circular cross-sectional shape are arranged coaxially, and includes a line in which an inner conductor and an outer conductor having a circular or elliptical cross-sectional shape are arranged. In addition, the arrangement in which the focal point of the ellipse and the center position of the inner conductor coincide with each other can be regarded as a coaxial arrangement in the sense that a microwave transmission space is formed between the inner conductor and the outer conductor. Shall be composed.

  Since microwave power is consumed for plasma generation, the microwave attenuates as it travels. When the plasma is stretched until all the microwave power is consumed, discharge light emission occurs in the plasma stretching range. The discharge state is maintained by continuing to supply the microwave.

  In this way, discharge light emission occurs in the path of microwave propagation through the coaxial line, so it is possible to extract light radially from the discharge tube, and irradiate light over a wide range according to the length of the discharge tube in the tube axis direction. The light can be extracted at any position along the tube axis direction. Since microwave power is consumed for plasma generation, it is preferable to supply a microwave having power that can extend the plasma to the vicinity of the other end of the discharge tube to the end of the discharge tube.

  Although the light may be irradiated radially in any direction, when the light is irradiated toward the irradiation target, it is preferable to partially provide a light passage portion that allows the light to pass through the tubular conductor. For example, an opening is partially formed, or a metal mesh is provided to transmit light.

  Waveguides and three-dimensional circuit elements increase the size of the lamp structure and complicate the circuit configuration. In order to discharge and emit light without using such components, it is desirable to connect the end of the discharge tube to the output of the microwave oscillator and supply the microwave directly.

  In order to securely fix the discharge tube coaxially and output the microwave coaxially to the discharge tube, for example, the output portion of the microwave oscillator and the end of the discharge tube are connected, and a relay conductor portion that functions as an inner conductor is provided. Good. In order to suppress the reflection of the microwave, it is preferable to provide an impedance matching jig extending from the relay conductor portion along the tube axis direction and having a tube axis length of 1/4 wavelength of the microwave.

  Alternatively, in order to use a conventional microwave waveguide or a three-dimensional circuit element, a waveguide for transmitting the microwave output from the microwave oscillator is provided, and the end of the discharge tube is inserted into the waveguide to guide the wave. The microwave in the tube is preferably supplied to the end of the discharge tube. For example, in a tubular section for inserting a discharge tube and a waveguide provided with a variable short circuit, the plasma in the discharge tube and the tubular section of the waveguide act as an inner conductor and an outer conductor of the coaxial line, respectively, and in the coaxial mode A wave is supplied to the end of the discharge tube.

  As the configuration of the tubular conductor, a conductor tube surrounding the discharge tube may be formed so as to provide a space and a gap therebetween, or a metal film or the like may be formed on the outer surface of the discharge tube. . When a conductor tube is separately provided, the microwave propagates in the tube wall of the discharge tube and the space formed between the discharge tube and the conductor tube. On the other hand, when the tubular conductor is formed in close contact with the outer surface of the discharge tube, the microwave propagates in the tube wall of the discharge tube.

  When the discharge tube is made of quartz glass and the discharge light emission is vacuum ultraviolet light, the discharge tube absorbs light and the light emission efficiency decreases. Therefore, the discharge tube cannot be made too thick. Thus, in order to be able to adapt and cope with conditions such as the discharge conditions and the structural characteristics of the discharge tube, it is preferable to arrange a conductor tube separately and provide a space between the discharge tube. On the other hand, when the conventional lamp structure is utilized as much as possible to reduce the size, a tubular conductor is preferably formed on the outer surface of the discharge tube, and the discharge tube and the tubular conductor are integrated to form a coaxial line.

  In order to extract light efficiently while preventing leakage of microwaves, it is conceivable to dispose a metal mesh. However, in order to efficiently radiate light directly in a specific direction as a light source, it is desirable to form a slit that allows light to pass along the tube axis direction in the tubular conductor.

  In order to condense the light emitted in the direction where the slit is not formed as much as possible and emit it to the outside, the conductor tube is formed in an elliptical cross-sectional shape, and the discharge tube is arranged near one elliptical focal point, while the other ellipse is arranged. It is preferable to form a slit near the focal point. Since the light emitted from the discharge tube is collected at the other elliptical focal point, the light due to the discharge is emitted to the outside without any loss. In particular, in order to increase the light collection rate, it is preferable to form a light reflecting film on the inner surface of the conductor tube.

  During discharge light emission, the microwave power is consumed while propagating, so that the light intensity decreases to some extent as the plasma extends. In order to make the light intensity along the tube axis direction constant, it is desirable to provide two microwave oscillators at both ends of the discharge tube and supply microwaves from both sides of the discharge tube.

  In this case, in order to prevent the interference of the microwaves, it is preferable that the two microwave oscillators alternately operate intermittently and supply the microwaves alternately to both ends of the discharge tube. The illuminance distribution becomes uniform by the alternating pulse discharge. If microwaves are oscillated using a commercial power supply, half-wave rectifier circuits may be provided for the power supplies of the two microwave oscillators, and the phases may be shifted from each other.

  The microwave discharge lamp of the present invention includes a discharge tube in which a discharge gas is enclosed, a conductor that surrounds the discharge tube along the tube axis direction, and plasma and a conductor generated in the discharge tube as an inner conductor and an outer conductor, respectively. Microwave supply means for supplying a microwave to the end of the coaxial line.

  The microwave to be supplied may be a frequency and electric power at which microwave propagation and plasma stretching continue in the discharge tube after being supplied to the end of the discharge tube, and when emitting light with higher density and higher brightness. It is better to set the frequency higher. In order to efficiently supply microwaves when using a long discharge tube (long enough in the tube axis direction with respect to the diameter), the microwave supply means can be coaxially connected to the end of the discharge tube. Should be output coaxially.

  The microwave discharge light emitting part of the present invention can be connected to a microwave oscillator such as a magnetron (particularly a microwave oscillator having a coaxial output part for coaxially outputting a microwave), and a discharge tube in which a discharge gas is sealed. , A conductor surrounding the discharge tube along the tube axis direction, microwaves are supplied to the end of the discharge tube, and the plasma and conductor generated in the discharge tube during discharge are configured as the inner conductor and outer conductor of the coaxial line, respectively Is done.

  ADVANTAGE OF THE INVENTION According to this invention, the microwave discharge lamp which can irradiate light efficiently over a wide range can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a microwave discharge lamp according to the first embodiment. FIG. 2 is a cross-sectional view of the microwave discharge lamp taken along line II-II in FIG.

  The microwave discharge lamp 10 includes two coaxial output magnetrons (hereinafter referred to as coaxial output magnetrons) 12A and 12B that oscillate microwaves, and a discharge light emitting unit 20, and coaxial output magnetrons 12A, 12B is installed. The discharge light emitting unit 20 includes a cylindrical conductor tube 30 and a cylindrical discharge tube 40, and the discharge tube 40 is inserted and disposed inside the conductor tube 30. As will be described later, the conductor tube 30 and the discharge tube 40 are coaxially connected to the coaxial output portions 60A and 60B of the coaxial output magnetrons 12A and 12B at the positions of the rings 22A and 22B.

  The discharge tube 40 made of quartz is a long (1 m or more in this case) thin discharge tube with both ends sealed off, and a dielectric support portion (between the conductive rings 22A and 22B ( (Not shown) is held at the center of the conductor tube 30. The conductor tube 30 made of metal or the like surrounds the entire discharge tube 40 along the tube axis direction.

  As shown in FIG. 2, the discharge tube 40 is disposed coaxially with the axis E of the conductor tube 30. In the discharge space DS in the discharge tube 40, a mixed gas of carbon monoxide (CO) and xenon (Xe) is sealed at a predetermined sealing pressure, and vacuum ultraviolet light is emitted in the range of 150 to 200 nm by discharge light emission. Is done.

  A space TS (hereinafter referred to as a transmission space) TS between the conductor tube 30 and the discharge tube 40 is a space in which microwaves propagate along the tube axis direction as will be described later. The portions 30H are formed in the tube axis direction at predetermined intervals. Here, in order to efficiently extract light to the outside, nitrogen that does not absorb vacuum ultraviolet light is supplied into the transmission space TS through the opening 30H.

  A slit 30S for radiating vacuum ultraviolet light by discharge light emission to the outside is formed in the lower part of the conductor tube 30 along the tube axis direction. The size of the slit 30S is determined so that the propagating microwave does not leak.

  The inner surface of the conductor tube 30 is coated with a reflective film 32 having a high reflectance with respect to vacuum ultraviolet light, and the vacuum ultraviolet light emitted from the discharge space DS is reflected by the reflective film 32 and passes through the slit 30S to the outside. To inject. Thereby, a vacuum ultraviolet light irradiates a board | substrate (not shown) etc. which are arrange | positioned under a lamp | ramp etc. with a line.

  FIG. 3 is a configuration diagram showing the connection portion between the coaxial output magnetron 12 </ b> A and the discharge tube 40 as viewed from the inside of the discharge light emitting unit 20.

  The coaxial output portion 60A of the coaxial output magnetron 12A includes a ring-shaped outer conductor portion 62A and an inner conductor portion 50A. An inner conductor portion 50A such as a copper pipe is directly connected and fixed to the antenna 14A serving as a microwave output portion, and an outer conductor portion 62A is fixed to the grounded conductive casing 12A1 of the coaxial output magnetron 12A. .

  The inner conductor portion 50A connects one end portion 40A of the discharge tube 40 and the antenna 14A, and constitutes a coaxial line together with the outer conductor portion 62A. Thus, the coaxial mode microwave composed of the inner conductor portion 50A and the outer conductor portion 62A is directly output from the coaxial output magnetron 12A. Here, the coaxial output unit 60A is configured in accordance with a standard such as WX-39D.

  The end portion 40A of the discharge tube 40 is directly inserted and fixed to the inner conductor portion 50A. In addition, the conductor tube 30 and the outer conductor portion 62A are fitted at both ends of the conductive ring 22A, whereby the conductor tube 30 and the outer conductor portion 62A are electrically connected. The distance M between the conductor tube 30 and the outer conductor 62A can be adjusted, and the ring 22A is positioned by tightening a hose band or the like from the outside of the ring. On the other hand, an impedance matching jig 52A is provided at a connection portion between the inner conductor portion 50A and the discharge tube end portion 40A. The impedance matching jig 52A extends in the tube axis direction from the end of the inner conductor portion 50A toward the coaxial output magnetron 12B, and the length in the tube axis direction is set to ¼ of the wavelength λ of the microwave to be supplied. ing.

The length (1 / 4λ) of the impedance matching jig 52A is determined so as to suppress the reflection of the microwave, and the characteristic impedance Z ₀ of the coaxial output portion 60A and the plasma generated in the discharge tube 40 are connected to the inner conductor, The geometric impedance of the characteristic impedance Zp of the coaxial line configured with the conductor tube 30 as the outer conductor is the characteristic impedance Z _{c in the} range L in which the plasma generated in the impedance matching jig 52A and the discharge tube 40 is aligned along the tube axis direction (Z _c = (Z ₀ Z _p ) ^1/2 ).

  The connecting portion between the coaxial output magnetron 12B on the opposite side and the discharge tube 40 has the same configuration, and the other end portion 40B of the discharge tube 40 is coaxially connected to the inner conductor portion 50B, and the outside of the coaxial output magnetron 12B. The conductor 62B is fixed to the housing 12B1 and is electrically connected to the conductor tube 30. An impedance matching jig 52B is provided at the tip of the inner conductor portion 50B.

  The coaxial output magnetrons 12A and 12B constitute microwave power sources 17A and 17B together with transformers 15A and 15B and half-wave rectifier circuits 16A and 16B that convert an AC voltage supplied from a commercial power source into a high voltage, and the half-wave rectifier circuit 16A. , 16B, and ON / OFF operation according to the half-wave rectification. That is, the microwave is oscillated while being interrupted every half cycle of the commercial frequency. The input power supply phases of the microwave power supplies 17A and 17B are set to be shifted by 180 degrees in advance, and microwaves are alternately oscillated from the coaxial output magnetron 12A and the coaxial output magnetron 12B.

  FIG. 4 is a diagram showing a mechanism of discharge light emission in the microwave discharge lamp 10.

  As described above, the coaxial output portions 60A and 60B of the coaxial output magnetrons 12A and 12B constitute a coaxial line using the inner conductor portions 50A and 50B and the outer conductor portions 62A and 62B as the inner conductor and outer conductor of the coaxial line, respectively.

  The microwave output from the coaxial output magnetron 12A is supplied to the coaxial output unit 60A in the coaxial TEM mode, whereby the microwave is propagated coaxially. That is, the microwave propagates between the inner conductor portion 50A and the outer conductor portion 62A along the tube axis direction.

  At the end portion 40A of the discharge tube 40 that is coaxially coupled to the inner conductor portion 50A, the discharge gas becomes a plasma state by the supply of microwave power through the inner conductor portion 50A, and discharge light emission occurs (in FIG. 4, the plasma generation portion). P is shown as a spot).

  The discharge gas is originally in an insulating state, but becomes conductive when in a plasma state. That is, the plasma generated in the discharge space DS becomes a conductor and has the same structure as the coaxial line in which the inner conductor is formed inside the conductor tube 30. As a result, the microwave propagates between the plasma in the discharge space DS and the conductor tube 30, that is, the tube wall portion of the discharge tube 40 and the transmission space TS.

  When the microwave is transmitted in the tube axis direction, the discharge gas separated from the end 40A of the discharge tube 40 by the supply of the microwave power is also in a plasma state, and discharges light. The plasma generation portion functions as an inner conductor of the coaxial line, and the microwave further propagates in the tube axis direction, thereby further generating plasma.

  In this way, the microwave propagation and the plasma generation are complementarily continued, so that the plasma extends in the tube axis direction. Since microwave power is consumed for plasma generation, the microwave decays as it travels. If all microwave power is consumed for plasma generation, the plasma will no longer stretch.

  Here, the microwave power is set according to the length of the discharge tube 40, and the microwave propagates to the end 40 </ b> B of the discharge tube 40. As a result, plasma is generated over the entire discharge tube, and vacuum ultraviolet light is emitted from the entire discharge tube. Since almost all of the microwave power is consumed, there is almost no reflection of the microwave at the end 40B of the discharge tube 40 and leakage of the microwave beyond the end 40B.

  The same applies to the microwave supplied from the coaxial output magnetron 12B on the opposite side, and the microwave propagates to the end 40A of the discharge tube 40, whereby the plasma extends to the entire discharge tube.

  As described above, the coaxial output magnetrons 12A and 12B operate intermittently alternately, and therefore discharge light is emitted by alternating pulse discharge. As a result, the density of plasma extending from both sides of the discharge tube 40 becomes uniform in the tube axis direction on a time average, and vacuum ultraviolet light having a substantially uniform light emission intensity is irradiated downward.

  As described above, according to the present embodiment, in the microwave discharge lamp 10 including the long discharge tube 40, the two coaxial output magnetrons 12A and 12B are coaxially coupled to the both end portions 40A and 40B of the discharge tube 40, and the discharge is performed. The conductor tube 30 is disposed so as to surround the tube 40 along the tube axis direction.

  When coaxial mode microwaves are alternately supplied to the end portions 40A and 40B of the discharge tube 40 by the coaxial output magnetrons 12A and 12B, plasma generation and microwave propagation proceed in a complementary manner. Ultraviolet light is emitted. And a vacuum ultraviolet light is irradiated to a board | substrate etc. through the slit 30S formed in the conductor tube 30. FIG.

  Since light can be emitted over the entire long discharge tube 40 without using a resonator, the light can be efficiently taken out over a wide range, and a lamp with excellent luminous efficiency is provided. be able to. Further, since the microwave power is supplied in accordance with the length of the long discharge tube 40, the lamp can be lit with the supplied power minimized.

  Further, by coaxially coupling the coaxial output magnetrons 12A and 12B and the discharge tube 40 to output the microwaves coaxially, an impedance matching unit, a coaxial converter, and the like are not required to have complicated and expensive three-dimensional circuit elements, and are inexpensive. A lamp with high luminous efficiency can be realized with the device configuration.

  Further, by supplying microwaves alternately from the coaxial output magnetrons 12A and 12B provided at both ends of the discharge tube 40 to the discharge tube 40, vacuum ultraviolet light whose light intensity is uniform in time average is radiated from the discharge tube 40. . Thereby, it can be used as a light source for an object such as a substrate having a strict requirement for constant illuminance. Further, since microwaves are alternately supplied to the discharge tube 40, interference of microwaves can be suppressed.

  In addition, impedance matching jigs 52A and 52B are provided at both end portions 40A and 40B of the discharge tube 40, so that reflection of microwaves at the connecting portion is prevented, and microwave power is utilized to the maximum for plasma generation.

  Next, the microwave discharge lamp which is 2nd Embodiment is demonstrated using FIG. In the second embodiment, the cross section of the conductor tube covering the discharge tube is formed in an elliptical shape. Other configurations are substantially the same as those in the first embodiment.

  FIG. 5 is a cross-sectional view of the discharge part of the microwave discharge lamp according to the second embodiment.

  As shown in FIG. 5, the conductor tube 130 of the microwave discharge lamp 100 has an elliptical cross-sectional shape, and the discharge tube 40 is positioned so that the axis E of the discharge tube 40 coincides with the focal point of the ellipse. The output portions of two coaxial output magnetrons (not shown here) are coaxially connected in accordance with the position of the discharge tube 40.

  Since the cross section of the conductor tube 130 is elliptical, vacuum ultraviolet light emitted from the discharge tube 40 is collected by the reflective film 132 in the other elliptical focal direction. Since the slit 130S is formed near the other elliptical focal position, the vacuum ultraviolet light can be effectively taken out to the outside. Note that a conductor tube having a pseudo elliptical cross-sectional shape may be configured by a combination of cylinders.

  Note that, as in the first and second embodiments, a slit may not be formed in the conductor tube, and a metal mesh may be provided to extract light to the outside. Further, when irradiating light in a wavelength region other than vacuum ultraviolet light, air may be configured to enter the transmission space TS in the conductor tube 30 for cooling. The discharge tube may be made of a dielectric material such as ceramics other than quartz glass, and the conductor tube only needs to have conductivity.

  The discharge gas sealed in the discharge tube 40 may be a gas other than CO and Xe, or may emit light other than vacuum ultraviolet light. Moreover, you may comprise so that a fluorescent substance may be coated on the inner wall of the discharge tube 40 or the conductor tube 30, and visible light may be irradiated outside. Further, one coaxial output magnetron may be coaxially coupled to one end of the discharge tube, and microwaves may be supplied from only one of the discharge tubes.

  Furthermore, the microwave to be supplied to the discharge tube may be a microwave having a frequency and electric power that allows plasma discharge to continue to the end of the discharge tube and enables stable discharge.

  The microwave discharge lamp which is 3rd Embodiment is demonstrated using FIG. In the third embodiment, a waveguide, a three-dimensional circuit element, and the like are provided, and a discharge tube end is disposed in the waveguide. Other configurations are substantially the same as those in the first embodiment.

  FIG. 6 is a schematic configuration diagram of a microwave discharge lamp according to the third embodiment.

  The microwave discharge lamp 200 includes a waveguide 210 and a magnetron 220, and an impedance matching unit 230, a three-dimensional circuit element 250 including a power monitor and an isolator are disposed in the waveguide 210. A movable short circuit (termination) device 260 is provided at the end of the waveguide 210, and a tubular portion 210A perpendicular to the axial direction of the waveguide 210 is integrally formed. Here, the discharge tube 240 is arranged so that the end portion 240A of the discharge tube 240 is inserted into the tubular portion 210A. As a result, when the plasma generated in the discharge tube 240 and the tubular portion 210A function as an inner conductor and an outer conductor of the coaxial line, respectively, and microwaves are supplied into the waveguide, they are the same as the waveguide-coaxial converter. It becomes a composition.

  The discharge tube 240 is a long, thick discharge tube made of quartz, and the outer surface of the discharge tube 240 is coated with an aluminum vapor deposition film 242. A slit (not shown) for extracting light is formed in the aluminum vapor deposition film 242 along the tube axis direction.

  The microwave output from the magnetron 220 passes through the three-dimensional circuit element 250 and is then supplied to a resonator formed between the impedance matching unit 230 and the movable terminator 260, thereby causing plasma to be generated at the end of the discharge tube 240. Will occur. The aluminum vapor deposition film 242 functions as the outer conductor of the coaxial line and the plasma functions as the inner conductor of the coaxial line, and the microwave propagates in the tube wall of the insulating discharge tube 240. Microwave propagation and plasma stretching continue to the other end 240B of the discharge tube 240, and vacuum ultraviolet light is extracted from the slit of the discharge tube 240 over the entire tube axis direction.

  A conductive substance other than the aluminum vapor deposition film may be formed on the surface of the discharge tube. Further, in the first and second embodiments, instead of separately providing a conductor tube, a discharge tube in which the inner conductor and the outer conductor shown in the third embodiment are integrated may be applied.

It is a schematic block diagram of the microwave discharge lamp which is 1st Embodiment. It is sectional drawing of the microwave discharge lamp along II-II of FIG. It is the block diagram which showed the connection part of a magnetron and a discharge tube seeing from the inside of a discharge light emission part. It is the figure which showed the mechanism of the discharge light emission in a microwave discharge lamp. It is discharge part sectional drawing of the microwave discharge lamp which is 2nd Embodiment. It is a schematic block diagram of the microwave discharge lamp which is 3rd Embodiment.

Explanation of symbols

10, 100, 200 Microwave discharge lamps 12A, 12B, 220 Magnetron (microwave oscillator)
20 Discharge light emitting part 30, 130 Conductor tube (tubular conductor)
40, 240 Discharge tube 242 Aluminum vapor deposited film (tubular conductor)
40A, 40B End of discharge tube 50A, 50B Inner conductor (relay conductor)
52A, 52B Impedance matching jig

Claims (14)

A microwave discharge lamp that is an electrodeless discharge lamp that emits light by being supplied with microwave power,
At least one microwave oscillator for oscillating microwaves;
A discharge tube in which discharge gas is enclosed and microwaves are supplied to one end;
A tubular conductor covering the discharge tube over the entire tube axis direction,
When the microwave power is supplied, plasma generated in the discharge tube forms an inner conductor of the coaxial line, and the tubular conductor becomes an outer conductor of the coaxial line, so that the microwave is directed toward the other end of the discharge tube. Propagating in the tube axis direction, and with the propagation of microwaves, the plasma extends in the tube axis direction toward the other end of the discharge tube,
A microwave having power that extends the plasma to the vicinity of the other end of the discharge tube is supplied to the end of the discharge tube ,
The end of the discharge tube is coaxially connected to the output of the microwave oscillator,
A microwave discharge lamp , further comprising a relay conductor portion that connects an output portion of the microwave oscillator and an end portion of the discharge tube and functions as an inner conductor of a coaxial line .   The microwave discharge lamp according to claim 1, wherein the microwave propagates between the tubular conductor and the plasma. 2. The microwave discharge according to claim 1 , further comprising an impedance matching jig extending along the tube axis direction from the relay conductor portion and having a tube axis direction length of ¼ wavelength of the microwave. lamp. A waveguide for transmitting microwaves from the microwave oscillator;
The microwave discharge lamp according to claim 1, wherein an end of the discharge tube is inserted into the waveguide. The microwave discharge lamp according to any one of claims 1 to 4 , wherein the tubular conductor partially has a light passage portion that allows light to pass therethrough. A microwave discharge lamp that is an electrodeless discharge lamp that emits light by being supplied with microwave power,
At least one microwave oscillator for oscillating microwaves;
A discharge tube in which discharge gas is enclosed and microwaves are supplied to one end;
A tubular conductor covering the discharge tube over the entire tube axis direction,
When the microwave power is supplied, plasma generated in the discharge tube forms an inner conductor of the coaxial line, and the tubular conductor becomes an outer conductor of the coaxial line, so that the microwave is directed toward the other end of the discharge tube. Propagating in the tube axis direction, and with the propagation of microwaves, the plasma extends in the tube axis direction toward the other end of the discharge tube,
A microwave having power that extends the plasma to the vicinity of the other end of the discharge tube is supplied to the end of the discharge tube ,
The tubular conductor has a conductor tube that surrounds the discharge tube with a space in between ,
The tubular conductor has a slit that allows light to pass along the tube axis direction ;
Wherein a conductor pipe an elliptical cross-sectional shape, it is disposed the discharge tube in the vicinity of one of the ellipse focus, features and to luma microwave discharge lamp in that the slit is formed near the other ellipse focus. The microwave discharge lamp according to claim 6 , wherein a light reflection film is formed on an inner surface of the conductor tube. The microwave discharge lamp according to any one of claims 6 to 7 , wherein the conductor tube has an injection hole for taking in a gas. The microwave discharge lamp according to any one of claims 1 to 5 , wherein the tubular conductor is formed on an outer surface of the discharge tube. The microwave discharge lamp according to any one of claims 1 to 9 , wherein two microwave oscillators respectively supply microwaves to both ends of the discharge tube. The microwave discharge lamp according to claim 10 , wherein the two microwave oscillators alternately operate intermittently to supply microwaves alternately to both ends of the discharge tube. The microwave discharge lamp according to claim 11 , wherein the power sources of the two microwave oscillators each have a half-wave rectifier circuit and are out of phase with each other. The microwave discharge lamp according to any one of claims 1 to 12 , wherein a mixed gas of CO and Xe is enclosed in the discharge tube. A microwave discharge lamp that is an electrodeless discharge lamp that emits light by being supplied with microwave power,
A discharge tube filled with discharge gas;
A conductor covering the discharge tube over the entire tube axis direction;
A microwave supply means for supplying a microwave to one end of the discharge tube,
When the microwave power is supplied, plasma generated in the discharge tube forms an inner conductor of the coaxial line, and the tubular conductor becomes an outer conductor of the coaxial line, so that the microwave is directed toward the other end of the discharge tube. Propagating in the tube axis direction, and with the propagation of microwaves, the plasma extends in the tube axis direction toward the other end of the discharge tube,
The microwave supply means supplies a microwave having electric power for extending the plasma to the vicinity of the other end of the discharge tube to the end of the discharge tube ;
The end of the discharge tube is coaxially connected to the output of the microwave oscillator,
The microwave discharge lamp further comprising a relay conductor portion that connects an output portion of the microwave oscillator and an end portion of the discharge tube and functions as an inner conductor of a coaxial line.

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