JP2011060505A - Housing for microwave lamp, the microwave lamp, light source device, and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a housing for a microwave lamp that can efficiently prevent leakage of microwaves and transmit the energy of microwaves to plasma, and a microwave lamp that can enhance the light-emission efficiency and light pick-p efficiency, and to provide a light source device and a projector. <P>SOLUTION: A housing 13 for a microwave lamp includes central conductors 8A, 8B, a conductor cylinder 7 and connectors 4A, 4B. When the wavelength of the microwave is λg, n is an integer of 0 or larger and m is a natural number, the conductor cylinder 7 includes a resonant part whose length in the axial direction is set e to be m times λg/4; an impedance matching part whose length in the axis direction is set to be m times λg/4; and an impedance keeper portion whose length in the axial direction is set to be m times λg/16; a mounting position of a light emission tube is set at a position away from an opening end by 2n times λg/4; and the inside diameter of the impedance matching part is reduce, as going toward a side of the impedance keeper part from the side of a resonant part, and an external conductor 7 has, on its inner side, metal pieces 7c, 7c for determining the resonance length of the microwaves. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a casing for a microwave lamp, a microwave lamp, a light source device, and a projector.

  In recent years, electrodeless discharge lamps using a microwave discharge method have been actively developed as light source devices used in projectors. Unlike electrode discharge lamps such as conventional incandescent lamps and high-pressure mercury lamps, electrodeless discharge lamps do not have discharge electrodes inside the arc tube (for example, Patent Documents 1 to 3). For this reason, the consumption of the filament and the electrode is suppressed, which is expected as a long-life light source.

  Such an electrodeless discharge lamp has a structure in which microwaves are resonated using the principle of an antenna and light is emitted by supplying microwave energy to an arc tube. For example, in Patent Documents 4 and 5, a pair of electrodes protrudes into a light emitting space of a light emitting tube in which a light emitting substance is sealed, and are arranged to face each other with a predetermined distance therebetween, thereby providing a high impedance part at the center of the light emitting part. Is forming. A power source for generating microwaves is generated on one of the pair of electrodes to emit light from the light emitting portion.

  A cylindrical cavity structure using a TE or TM mode microwave propagating through a transmission line covered with a metal outer wall has also been proposed. In Patent Document 6, a cylindrical cavity using a dielectric such as alumina is used.

Japanese Patent Laid-Open No. 2001-102005 JP 2001-256926 A JP 2002-75290 A JP 2007-115547 A JP 2007-115534 A JP-T-2004-505429

  However, among the techniques of the above documents, there is a concern about leakage of microwaves to be supplied in the case of a structure that emits light using the principle of the antenna. In the case of the conventional configuration, it is difficult to improve the light emission efficiency because the impedance matching on the input end side is insufficient.

  The present invention has been made in view of the above-mentioned problems of the prior art, and has a resonance structure in which microwave leakage is prevented and microwave energy is confined in a plasma portion. By using the mode and impedance matching, it is possible to efficiently transmit power to the plasma. Furthermore, it is a housing for a microwave lamp that can increase the light extraction efficiency. In view of the above, an object is to provide a microwave lamp, a light source device, and a projector with extremely high luminous efficiency.

  In order to solve the above problems, a housing for a microwave lamp according to the present invention has a conductor tube portion at least one end of which is an open end, a center conductor disposed along the central axis of the conductor tube portion, A microwave lamp housing having a connector connected to one end of the central conductor, where the wavelength of the microwave is λg, n is an integer greater than or equal to 0, and m is a natural number, And an arc tube mounting portion at a position 2n times λg / 4 from the opening end in the central axis direction of the conductor tube portion, and the conductor tube portion has a length in the center axis direction of λg / 4 a resonance part that resonates a microwave of a TEM mode that is m times, a matching part that has a length in the central axis direction that is m times λg / 4, and performs impedance matching between the resonance part and the connector, and the center Axial length is m times λg / 16 And an impedance keeper portion provided between the connector and the matching portion, and an inner diameter of the matching portion is reduced from the resonance portion side toward the impedance keeper portion side, A convex portion that determines the resonance length of the microwave is provided on the inner surface of the conductor tube portion, and the convex portion is provided at a position that is n times λg / 4 from the opening end when the m is an even number. When m is an odd number, it is provided at a boundary position between the resonance part and the impedance keeper part.

The present invention is a housing for a microwave lamp in which an arc tube can be attached to the inside of a conductor tube portion having the above-described dimensions, and the impedance matching portion can stabilize the microwave while the impedance keeper portion can stabilize the microwave. Impedance matching with the input end side (connector) is performed, and microwave energy can be efficiently supplied to the plasma by the resonance part. By imparting a resonance and impedance matching function to the casing, which is a component of the microwave lamp, the configuration can be simplified and the microwave transmission efficiency can be improved.
Moreover, the leakage using the microwave can be effectively prevented by generating resonance using the TEM mode by the conductor cylinder portion having the above dimensions. Furthermore, by attaching the arc tube to the conductor tube portion at the above position, the microwave energy can be maximized at the center of the arc tube. For this reason, a lamp with high luminance emission can be obtained.
Further, by providing the convex portion inside the outer conductor, the order of the TEM resonance mode is determined, and an effective resonance structure is obtained, and the microwave utilization efficiency is improved.

  In order to solve the above problems, a microwave arc tube according to the present invention includes a conductor tube portion having an open end at least one end, a center conductor disposed along a center axis of the conductor tube portion, and the center conductor. And a short member for connecting the resonance part and the central conductor, wherein the microwave wavelength is λg, and n is 0 or more. When m is a natural number, the wavelength of the microwave is λg, n is an integer of 0 or more, and m is a natural number, the central conductor is λg from the opening end in the central axis direction of the conductor tube portion. / 4 of the arc tube mounting portion at a position 2n + 1 times, the conductor tube portion having a length in the central axis direction of m times λg / 4, and a resonance portion for resonating TEM mode microwaves. The length in the central axis direction is m times λg / 4. A matching unit that performs impedance matching between the resonance unit and the connector, and an impedance keeper unit that has a length in the central axis direction that is m times λg / 16 and is provided between the connector and the matching unit. The matching portion has an inner diameter that is reduced from the resonance portion side toward the impedance keeper portion side, and a convex portion that determines a resonance length of the microwave is provided on the inner surface of the conductor tube portion. The convex portion is provided at a position n times λg / 4 from the opening end when the m is an even number, and between the resonance portion and the impedance keeper portion when the m is an odd number. It is provided at the boundary position.

The present invention is a housing for a microwave lamp in which an arc tube can be attached to the inside of a conductor tube portion having the above-described dimensions, and the impedance matching portion can stabilize the microwave while the impedance keeper portion can stabilize the microwave. Impedance matching with the input end side (connector) is performed, and microwave energy can be efficiently supplied to the plasma by the resonance part. By imparting a resonance and impedance matching function to the casing, which is a component of the microwave lamp, the configuration can be simplified and the microwave transmission efficiency can be improved.
Moreover, the leakage using the microwave can be effectively prevented by generating resonance using the TEM mode by the conductor cylinder portion having the above dimensions. Furthermore, by attaching the arc tube to the conductor tube portion at the above position, the microwave energy can be maximized at the center of the arc tube. For this reason, a lamp with high luminance emission can be obtained.
Further, by providing the convex portion inside the outer conductor, the order of the TEM resonance mode is determined, and an effective resonance structure is obtained, and the microwave utilization efficiency is improved.
Furthermore, in the present invention, since the resonance part and the central conductor are short-circuited by the short member, it is possible to more reliably prevent the leakage of the microwave from the opening end side.

Moreover, it is preferable that the inner surface of the said conductor cylinder part is made into an exponential shape.
According to the present invention, since the inner surface of the outer conductor has an exponential shape, an excellent impedance matching action can be obtained and transmission loss can be minimized. Thereby, it is possible to transmit microwave energy to plasma more efficiently.

The exponential shape has a length λg / 2, the characteristic impedance immediately before introduction of the microwave is Z ₀ , the impedance of the plasma portion is Z _L , the inner diameter of the conductor tube portion is D, the outer shape of the central conductor d, where the dielectric constant in the conductor tube portion is ε, a = (λg / 2) / log (Z _L / Z ₀ ), the change of the coaxial impedance with respect to the length (x) is Z (x) = Z _A curve satisfying the relationship of ₀ · EXP (−x / a) and Z (x) = 138 / √ε · log (D / d) is preferable.
According to the present invention, when the exponential shape of the inner surface of the outer conductor is a curve that satisfies the above conditions, it is possible to transmit microwave energy to the plasma more efficiently.

Moreover, it is preferable that the reflector is provided in the inside of the said conductor cylinder part.
According to the present invention, by providing the reflector inside the conductor tube portion, the emitted light from the arc tube can be reflected to the opening end side, so that the light utilization efficiency is improved and high luminance light is obtained. It is done.

Further, it is preferable that a coil is externally mounted on the central conductor, or that the central conductor is provided with irregularities to form a stub.
According to the present invention, the negative reactance of the arc tube can be canceled by creating the positive reactance by the coil or the stub, and the microwave power can be effectively transmitted into the plasma.

  A microwave lamp according to the present invention is a microwave lamp housing according to any one of claims 1 to 5, a light emitting tube in which a luminescent material excited by microwaves is enclosed and attached to the housing, It is provided with.

Moreover, it is preferable that the said uneven | corrugated | grooved part is a pair of metal piece opposingly arranged through the central axis of the said external conductor.
According to the present invention, by providing a pair of metal pieces inside the outer conductor, the order of the TEM resonance mode is determined, an effective resonance structure is obtained, and the microwave utilization efficiency is improved.

  ADVANTAGE OF THE INVENTION According to this invention, it can be set as the lamp | ramp which was excellent in luminous efficiency by providing the housing | casing for microwave lamps which can prevent the leakage of a microwave effectively and can improve the transmission efficiency. . The arc tube does not necessarily have an electrode in the arc tube like an arc discharge lamp.

The light source device of the present invention includes a microwave lamp, a microwave power source that generates a microwave, and a microwave transmission line that transmits the microwave generated in the microwave power source to the microwave lamp. It is characterized by.
According to the present invention, since the microwave lamp is provided, a light source device capable of emitting light with high power and high luminance can be provided.

A projector according to the present invention includes the light source device described above.
According to the present invention, since the light source device of the present invention described above is provided, a high-quality projector having excellent reliability can be provided.

The schematic diagram which shows the whole structure of the light source device of 1st Embodiment. The figure which shows schematic structure of the microwave lamp of 1st Embodiment. The figure which shows the structure of the microwave lamp of the light source device in 2nd Embodiment. Sectional drawing which shows the structure of the microwave lamp of the light source device in 3rd Embodiment. 1 is a schematic diagram showing a schematic configuration showing an embodiment of a projector. FIG.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.

(First embodiment)
FIG. 1 is a schematic diagram showing an overall configuration of a light source device according to a first embodiment of the present invention, FIG. 2A is a cross-sectional view showing a schematic configuration of a microwave lamp 12, and FIG. FIG. 2C is a side view seen from the side, and FIG. 2C is a side view seen from the input end side.
In the present embodiment, specific design dimensions in each part are determined according to the wavelength λg of the microwave. The wavelength λg is obtained by the speed of light / (frequency · √ε). When a microwave having a frequency in air of 2.45 GHz (Industry, Science, and Medical: ISM band) is used, the wavelength λg is 122.44 mm. Become. Hereinafter, in the dimension notation of each component, n is an integer of 0 or more, and m is a natural number. The impedance of the coaxial structure is determined by the ratio of the inner diameter (D) of the conductor tube portion and the outer diameter (d) of the center conductor, and is expressed as Z = 138 / √ε · log (D / d). Therefore, it is uniquely determined if the inner diameter of the conductor tube portion or the outer diameter of the central conductor is determined.

  As shown in FIG. 1, the light source device 1 of the present embodiment is mainly composed of a microwave power source 2, a microwave transmission line 3, and a microwave lamp 12, and a 2.45 GHz band TEM mode microwave (high frequency electromagnetic wave). It is configured to cope with.

  The microwave power source 2 generates a TEM mode microwave in the 2.45 GHz band, and is connected to the microwave lamp 12 via the microwave transmission line 3.

  The microwave transmission line 3 is used to transmit the microwave generated by the microwave power source 2 to the microwave lamp 12, and the characteristic impedance is maintained at 50Ω. Thereby, the microwave power can be efficiently supplied to the microwave lamp 12 without causing a loss. A first connector 4 </ b> A is provided at the end of the microwave transmission line 3.

  The first connector 4A (male side) is coupled to the second connector 4B (female side) provided on the microwave lamp 12, thereby electrically connecting the microwave transmission line 3 and the power feed attachment 9 of the microwave lamp 12. Connect. The first connector 4A is a low loss type whose characteristic impedance is matched to 50Ω which is the same as the characteristic impedance of the microwave transmission line 3, and an N-type connector is used here.

  As shown in FIG. 2A, the microwave lamp 12 includes a microwave lamp housing 13 including a conductor cylinder portion 7, a power supply attachment 9, and a second connector 4 </ b> B, a lamp portion 6, and a reflector 14. And is configured.

  The conductor tube portion 7 of this embodiment has an open coaxial structure in which at least one end is an open end, and has a function of concentrating microwaves on the lamp portion 6 connected and fixed to the power supply attachment 9. Have. The conductor cylinder portion 7 has an internal space constituted by a plurality of through holes 71, 72, 73 having different inner diameters, and the relationship between the inner diameters D1, D2, D3 of the through holes 71, 72, 73. Are D1 <D3, D2 ≦ D1, and D2 ≦ D3. Among these, the inner diameter D2 of the through hole 72 changes along the axial direction, and specifically, the diameter gradually decreases from the through hole 73 side toward the through hole 71 side.

In the present embodiment, in order to determine the order of the TEM resonance mode, the inside of the conductor tube portion 7 has a concavo-convex structure. Specifically, a pair of plate-like metal pieces 7c and 7c (convex portions) are provided at a position (near the axial direction of the through hole D3) separated from the opening end side (plasma light emitting portion) by n times λg / 4. It has been. These metal pieces 7 c and 7 c are disposed so as to face each other via the central axis O, and are provided in an upright state on the inner surface of the conductor tube portion 7. As described above, the resonance length of the microwave can be determined by projecting the metal pieces 7c, 7c from the inner wall of the conductor tube portion 7 to the center, and the microwave can be determined by changing the projection amount and the installation position. Phase adjustment can be performed.
The second connector 4B is attached to the conductor cylinder portion 7 in the through hole 71 located at the end portion on the opposite side in the axial direction from the opening 70 (FIG. 2B) through which light is emitted. .

The second connector 4B includes a plug 41, a plate-like mounter 42 provided on the plug 41, a packing 43 provided on the shaft portion 45 side of the mounter 42, and the mounter 42 for fixing the mounter 42 to the conductor tube portion 7. Screw holes 44 (FIG. 2 (c)). The packing 43 is made of an insulating material (or air), and is provided around the shaft portion 45 of the plug 41 in an annular shape. A microwave is supplied from the microwave transmission line 3 into the microwave lamp 12 by connecting the first connector 4 </ b> A on the microwave transmission line 3 side to the second connector 4 </ b> B. An N-type connector matched to 50Ω is also used for the second connector 4B.
In addition, the structure of the 2nd connector 4B mentioned above is an example, and is not limited to this.

  The power supply attachment 9 has a pair of central conductors 8A and 8B arranged along the central axis O of the conductor tube portion 7, and is arranged with the tips of each other facing each other in the internal space of the conductor tube portion 7. Has been. The center conductors 8A and 8B are made of a conductive material having a small coefficient of thermal expansion and high heat resistance. Of the pair of center conductors 8A and 8B, the center conductor 8B is fixed with one end connected to the second connector 4B, and the other center conductor 8A is coaxial with the center conductor 8B via the lamp portion 6. Is retained.

The center conductors 8A and 8B are formed with insertion holes 9a and 9b for inserting respective thin tube portions 16b and 16c of the ramp portion 6 to be described later on the respective distal end sides, and the distal ends facing each other at a predetermined interval. The lamp portion 6 can be held in a state where the bulging portion 16a is exposed between them. The outer diameters d1 and d2 of the center conductors 8A and 8B are set within a range of 0.5 to 3.0 mm in consideration of light extraction from the lamp unit 6, and d1 and d2 are both 2 mm here.
An insertion hole 9c is formed in the axial center portion of the center conductor 8B on the base end portion 8c side. By inserting the shaft portion 45 into the insertion hole 9c, the second connector 4B and the central conductor 8B are electrically connected.
In the present embodiment, the coil 18 is wound around the central conductor 8A. The coil 18 is disposed in the vicinity of the lamp portion 6 on the distal end side of the central conductor 8A.

  The lamp unit 6 includes an arc tube 16 in which a luminescent material is sealed and a pair of electrodes 11A and 11B, and is disposed on the central axis O. The arc tube 16 is made of quartz glass or the like, in which a bulging portion 16a having a spherical bulge at the center portion and narrow tube portions 16b and 16c extending on both sides of the bulging portion 16a are integrally formed.

  In the light emitting space formed in the bulging portion 16a, a light emitting material that emits light upon receiving microwaves is enclosed. As the luminescent substance, for example, mercury, rare gas, or halogen compound can be used. Note that a sufficient luminance can be obtained by microwave excitation by encapsulating the light-emitting substance with an ultrahigh pressure. The outer diameter of the bulging portion 16a is preferably about 6 mm or less.

  The electrodes 11A and 11B are formed using a conductive material having a small thermal expansion coefficient and high heat resistance, and have a predetermined interval (hereinafter referred to as a gap g) with their tip sides facing each other in the light emitting space of the bulging portion 16a. Is placed. In order to obtain high-luminance light emission close to a point light source, it is preferable to arrange the gap g between the electrodes 11A and 11B as small as possible.

  Such a lamp portion 6 is disposed at the highest electric field position in the conductor tube portion 7. In the present embodiment, the mounting portions provided on the center conductors 8A and 8B at positions 2n times λg / 4 (0, λ / 2, λ, λ · 3/2,...) From the opening 70 of the conductor tube portion 7. (Not shown). In FIG. 2A, the central portion of the gap g substantially coincides with the boundary between the through holes 72 and 73 of the conductor tube portion 7. In FIG. 2A, the central portion of the gap g coincides with the boundary between the through holes 72 and 73 of the conductor cylinder portion 7.

  Here, what is important for improving the energy efficiency of the light source device 1 as a whole is to match the characteristic impedance of the microwave transmission line 3 (connectors 4A and 4B) with the input impedance of the lamp unit 6. That is, the reflected wave from the lamp unit 6 to the microwave transmission line 3 (connectors 4A and 4B) is reduced to reduce transmission loss due to reflection.

  Therefore, the light source device 1 according to the present embodiment includes an impedance keeper 5A that suppresses fluctuations in microwave power from the microwave input end side of the microwave lamp 12, and an impedance matching unit 5B that performs impedance matching with the input side. And a resonance part 5C for resonating the microwave power.

Since the impedance Z ₀ at the time of plasma emission of a general high-pressure mercury lamp or metal halide lamp is 50 to 250Ω−j10 to 30Ω, the arc tube having an impedance Z ₀ of plasma emission of the lamp unit 6 (100 torr) = 200Ω−j10Ω. Is used, impedance matching is required between the connectors 4A and 4B (50Ω) and the resonance part 5C (200Ω).
Therefore, in this embodiment, the impedance matching unit 5B for matching the impedance on the connector 4A, 4B side and the impedance on the resonance unit 5C side is provided, so that the reflected wave from the resonance unit 5C is suppressed. .

  First, the impedance keeper 5A has a function of smoothly transmitting the microwave power supplied from the microwave transmission line 3 to the impedance matching unit 5B, and has a characteristic impedance of 50Ω. The axial length L1 of the conductor tube portion 7 in the impedance keeper portion 5A is defined by m times λg / 16, and the inner diameter D1 thereof is 4.6 mm. The impedance keeper unit 5A stably compensates for the TEM mode even when the load of the lamp unit 6 varies.

  The impedance matching portion 5B has a function of performing impedance matching between the impedance keeper portion 5A and the resonance portion 5C, and the axial length L2 of the conductor tube portion 7 in the portion is m times λg / 4. is there.

  The inner diameter D2 of the conductor tube portion 7 in the impedance matching portion 5B is reduced in diameter from the resonance portion 5C side to the impedance keeper portion 5A, and a gentle curve is drawn so that the inner surface 7b protrudes toward the axial center side. Yes. That is, the shape of the through hole 72 of the conductor tube portion 7 in the impedance matching portion 5B is an exponential shape. Therefore, the inner surface 7b of the through-hole 72 and the center conductor 8B can accurately match impedances with the input end side, thereby minimizing power reflection.

The resonating part 5C and the metal piece 7c have a function of resonating microwaves in the internal space, and the characteristic impedance is 200Ω. In the present embodiment, the axial length L3 of the resonance unit 5C is defined as m times λg / 4. Further, the inner diameter D3 of the conductor tube portion 7 in the resonance portion 5C is 56 mm.
The pair of metal pieces 7c and 7c that determine the order of the TEM resonance mode are arranged opposite to each other via the center axis O at the center position of the axial length L3 in the resonance portion 5C, that is, at a position λg / 4 times from the opening end. Has been.

The reflector 14 is disposed on the inner side of the conductor tube portion 7 and may be attached to the conductor tube portion 7 side, or may be attached to the center conductor 8B side. The reflector 14 includes a reflecting portion 14A having a curved reflecting surface 14a, and is formed of, for example, quartz glass. A dielectric multilayer film (not shown) that transmits microwaves and reflects light emitted from the lamp unit 6 is formed on the reflecting surface 14a. Thereby, the emission direction of the light reflected by the reflector 14 becomes a substantially constant direction.
Such a reflector 14 is disposed in the through hole 72 with the reflecting surface 14a facing the opening 70 side. At this time, by arranging the lamp unit 6 so that the position of the lamp unit 6 is on the reflection surface 14a side, the emitted light from the lamp unit 6 can be converted into parallel light and reflected to the opening 70 side.

  The light source device 1 of the present embodiment includes a microwave lamp 12 having an impedance keeper portion 5A including a conductor tube portion 7 and center conductors 8A and 8B having the above-described dimensions, an impedance matching portion 5B, and a resonance portion 5C. The impedance matching between the microwave transmission line 3 side and the resonance unit 5 side can be performed. As described above, by providing the casing 13 of the lamp 12 with the impedance matching function, it is not necessary to provide an external matching circuit, and the impedance matching function can be realized only by the constituent members of the casing 13. This makes it possible to improve the microwave transmission efficiency while simplifying the device configuration.

  In the present embodiment, the shape of the inner surface 7b of the conductor tube portion 7 in the impedance matching portion 5B is an exponential shape that extends from the impedance keeper portion 5A to the resonance portion 5C. Thus, by making the inner surface 7b of the conductor cylinder part 7 expand exponentially toward the resonance part 5C side, impedance matching with the input end side is accurately performed, and transmission loss is minimized. be able to. As a result, the reflection of power is suppressed, the failure of the connectors 4A and 4B is prevented, and the microwave energy can be efficiently supplied to the plasma. Therefore, the light source device 1 having excellent luminous efficiency and capable of emitting light with high power and low luminance can be obtained.

  Further, by providing an impedance keeper portion 5A having an impedance of 50Ω on the power input end side of the lamp 12, for example, even when the impedance slightly deviates from 50Ω due to the temperature rise of the first connector 4A, It becomes possible to allow fluctuations in impedance. Further, it is possible to stably compensate the TEM mode even when the load of the lamp unit 6 is changed.

In addition, since the lamp portion 6 is disposed at a position 2n times λg / 4 from the opening end of the conductor tube portion 7, the antinode of the standing wave amplitude of the microwave current is located at the lamp portion 6. Thus, high luminance light emission can be obtained.
Further, since the metal pieces 7c and 7c are arranged at a position n times as large as λg / 4 from the opening end, the order of the TEM resonance mode is determined, an effective resonance structure is obtained, and the utilization efficiency of the microwave is improved. .

  Further, in the present embodiment, the coil 18 is sheathed on the central conductor 8A. The impedance of the ramp unit 6 is expressed by R ± jX (real number + imaginary number), and has a negative reactance component as well as a real part. For this reason, a positive reactance is created by providing a coil in the central conductor 8A, and the microwave reactance is effectively transmitted into the plasma by canceling the negative reactance of the lamp unit 6 with high accuracy.

Further, by setting the conductor tube portion 7 and the central conductors 8A and 8B of the microwave lamp 12 to have the above-described dimensions, there is no microwave cutoff wavelength, and microwave leakage is preferably prevented. Thereby, the effect that there is no possibility of adversely affecting peripheral devices can be obtained, and the reliability can be improved.
Therefore, the light source device 1 of the present embodiment is a highly reliable light source that can emit light with high luminance and low power.

  Further, in the present embodiment, the reflector 14 is provided, so that the light incident on the reflector 14 out of the light emitted from the lamp unit 6 can be reflected to the opening 70 side. Thereby, the light extraction efficiency can be increased. Further, since the reflector 14 is made of a material that transmits microwaves, the transmission efficiency of the microwaves is not lowered, and the impedance matching function is not affected.

[Specific Example 1]
In this example, a light source device 1 configured to correspond to a 2.45 GHz band TEM mode microwave is shown, and FIGS. 1 and 2 are referred to. As described above, the specific dimension of the light source device 1 is determined according to the wavelength λg of the microwave and is 122.45 mm.
Below, each dimension of the microwave lamp 12 of the light source device 1 in this specific example is shown.
Impedance when lighting the lamp Z ₀ : 100Ω
(Impedance keeper 5A)
Axial length L1 of conductor tube portion 7: 7.6 mm (λg / 16)
Inner diameter D1 of conductor cylinder part 7: 26.8 mm
Outer diameter d3 of the base end portion 8c of the center conductor 8B: 8 mm
(Impedance matching unit 5B)
Axial length L2 of conductor cylinder portion 7: 61.22 mm (λg / 2)
The inner curve of the conductor tube portion 7 is
It is assumed that the dielectric constant ε of the air in the conductor tube portion 7 is a = (λg / 2) / log (Z _L / Z ₀ ), and the change with respect to the length (x) of the coaxial impedance is Z (x) = Z ₀ · EXP (−x / a) and Z (x) = 138 / √ε · log (D / d) are satisfied.
Center conductor 8B outer diameter d2: 9.484 mm
Outer diameter d3 of the base end portion 8c: 8.0 mm
(Lamp position)
The lamp unit 6 is installed so that the center thereof coincides with the boundary between the impedance matching unit 5B and the resonance unit 5C.
(Resonant part 5C)
Axial length L3: 61.22 mm (λg / 2)
Inner diameter D3: 50.0 mm
Center conductor 8A outer diameter d1: 9.484 mm
Position of the metal piece 7c: position of 30.61 mm from the opening end side (λg / 2)

(Second Embodiment)
Next, the light source device of 2nd Embodiment of this invention is demonstrated using FIG. FIG. 3A is a cross-sectional view showing the overall configuration of the microwave lamp of the second embodiment, and FIG. 3B is a side view seen from the input end side of the microwave lamp.
The basic configuration of the light source device of the present embodiment described below is substantially the same as that of the first embodiment, except that the short member 51 is provided on the open end side, and the lamp unit 6 is disposed on the resonance unit 5C side. The difference is that the metal pieces 7c, 7c are arranged at the boundary between the impedance matching portion 5B and the resonance portion 5C. Therefore, in the following description, the different parts will be described in detail, and description of common parts will be omitted. In each drawing used for the description, the same reference numerals are given to the same components as those in FIGS.

  In the light source device of the present embodiment, a short member 51 is provided on the open end side of the conductor tube portion 7. The short member 51 is made of a highly conductive metal such as aluminum or copper, and includes an annular member 51A and a cross bar 51B. The short member 51 is fixed to the conductor cylinder 7 and the power supply attachment 22 (center conductor 21A). Has been. By this short member 51, the conductor tube portion 7 and the power feeding attachment 22 (center conductor 21A) are electrically connected, and the conductor tube portion 7 and the power feeding attachment 22 can be held at the same potential. .

The lamp portion 6 is disposed on the resonance portion 5C side of the conductor tube portion 7 by a power feeding attachment 22 including a pair of center conductors 21A and 21B. In the present embodiment, the lamp portion 6 is arranged at a position 2n + 1 times λg / 4 from the opening end side of the conductor tube portion 7.
Further, the metal pieces 7c and 7c that determine the TEM resonance are arranged at the boundary between the resonance part 5C and the impedance matching part 5B, and thereby the order is determined.

  The center conductors 21A and 21B constituting the power supply attachment 22 are formed with a constant dimension without changing the outer diameter in the axial direction. As described above, since the lamp unit 6 is arranged on the resonance unit 5C side in the present embodiment, impedance matching can be performed satisfactorily even if the outer diameter of the center conductor 21B in the impedance matching unit 5B is constant in the axial direction.

  According to the configuration of the present embodiment, the open end is electrically shielded and the microwave leaks from the opening 70 by setting the conductor cylinder portion 7 and the power feeding attachment 9 to the same potential by the short member 51. It becomes possible to stop. That is, a part of the electric field generated by the microwave is canceled on the opening end side, and the microwave leakage preventing effect is further enhanced.

Note that the configuration of the short member 51 is not limited to the above, and any configuration that can short-circuit the conductor tube portion 7 and the power supply attachment 22 may be used. For example, a mesh member configured in a lattice shape is used. It may be adopted. Here, the short member 51 preferably has a shape capable of minimizing light blocked by the short member 51 out of light emitted from the opening 70.
In addition, since the metal pieces 7c and 7c are arranged at the boundary position between the resonance part 5C and the impedance matching part 5B, the order of the TEM resonance mode is determined, an effective resonance structure is obtained, and the microwave utilization efficiency is improved. improves.

[Specific Example 2]
In this example, the light source device 1 configured to support microwaves in the TEM mode in the 2.45 GHz band is shown, and FIGS. 3A and 3B are referred to. As described above, the specific dimension of the light source device 1 is determined according to the wavelength λg of the microwave and is 122.45 mm.
Below, each dimension of the microwave lamp 12 of the light source device 1 in this specific example is shown.
Impedance when lighting the lamp Z ₀ : 100Ω
(Impedance keeper 5A)
Axial length L1 of conductor tube portion 7: 7.6 mm (λg / 16)
Inner diameter D1 of conductor cylinder part 7: 26.8 mm
Outer diameter d3 of base end portion 8c of center conductor 8B: 8.0 mm
(Impedance matching unit 5B)
Axial length L2 of conductor cylinder portion 7: 61.22 mm (λg / 2)
The inner curve of the conductor tube portion 7 is
The inside of the conductor tube portion 7 is assumed to have a dielectric constant ε of air, a = (λg / 2) / log (Z _L / Z ₀ ), and the change with respect to the length (x) of the coaxial impedance is Z (x) = Z _0. EXP (−x / a) and Z (x) = 138 / √ε · log (D / d) are satisfied.
Center conductor 8B outer diameter d2: 9.484 mm
Outer diameter d3 of the base end portion 8c: 8.0 mm
(Lamp position)
The lamp 6 is installed so that the center thereof is located 30.62 mm (λg / 4) away from the positions of the impedance matching portion 5B and the resonance portion 5C.
(Resonant part 5C)
Axial length L3: 61.22 mm (λg / 2)
Inner diameter D3: 50.0 mm
Center conductor 8A outer diameter d1: 9.484 mm
Position of metal piece 7c: boundary position between impedance matching portion 5B and resonance portion 5C (short portion)
In order to bring the conductor tube portion 7 and the center conductor 8B into electrical contact, a cross-shaped short member 51 made of a metal conductor is provided at the end of the resonance portion 5C.

(Third embodiment)
Next, the light source device of 3rd Embodiment of this invention is demonstrated using FIG. FIG. 4 is a cross-sectional view showing the overall configuration of the microwave lamp of the light source device of the third embodiment.
As shown in FIG. 4, the light source device of the present embodiment includes a short member 51 on the open end side of the conductor tube portion 7, and the axial length of the conductor tube portion 7, that is, the axial length of the resonance portion 5C. Compared to the above embodiments, the configuration is shorter and the size is reduced.
As described above, the axial length of the resonance unit 5C is defined by m times λg / 4. In the previous embodiment, the axial length of the resonance portion 5C was set to λg / 2, but in this embodiment, the length is set to λg / 4. Accordingly, the axial length of the central conductor 8A is also shortened.

  According to the present embodiment, it is possible to reduce the size and weight of the microwave lamp 12 by shortening the axial length of the conductor tube portion 7 (resonating portion 5C). Even when the axial length of the conductor tube portion 7 is shortened, the above configuration increases the microwave transmission efficiency and effectively prevents microwave leakage as in the above embodiments. be able to. As a result, a light source device that is small, versatile and excellent in reliability can be obtained.

[Specific Example 3]
In this example, the configuration of the light source device 1 corresponding to the microwave in the 2.45 GHz band TEM mode is shown, and FIG. 4 is referred to. As described above, the specific dimension of the light source device 1 is determined according to the wavelength λg of the microwave and is 122.45 mm.
Below, each dimension of the microwave lamp 12 of the light source device 1 in this specific example is shown.
Impedance when lighting the lamp Z ₀ : 100Ω
(Impedance keeper 5A)
Axial length L1 of conductor tube portion 7: 7.6 mm (λg / 16)
Inner diameter D1 of conductor cylinder part 7: 26.8 mm
Outer diameter d3 of the base end portion 8c of the center conductor 8B: 8 mm
(Impedance matching unit 5B)
Axial length L2 of conductor cylinder portion 7: 61.22 mm (λg / 2)
The inner curve of the conductor tube portion 7 is
Assuming that the dielectric constant ε of the air in the conductor tube portion 7 is a = (λg / 2) / log (Z _L / Z ₀ ), the change of the coaxial impedance length (x) is Z (x) = Z ₀ · EXP (−x / a) and Z (x) = 138 / √ε · log (D / d) are satisfied.
Center conductor 8B outer diameter d2: 9.484 mm
Outer diameter d3 of the base end portion 8c: 8.0 mm
(Lamp position)
The center of the lamp 6 coincides with the boundary between the impedance matching part 5B and the resonance part 5C.
(Resonant part 5C)
Axial length L3 of conductor cylinder portion 7: 30.61 mm (λg / 4)
Inner diameter D3: 50.0 mm
Center conductor 8A outer diameter d3: 9.484 mm
(Short section)
In order to bring the conductor tube portion 7 and the center conductor 8B into electrical contact, a cross-shaped short member 51 made of a metal conductor is provided at the end of the resonance portion 5C.

  As described above, the preferred embodiments according to the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to the examples. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

  In the previous embodiment, one reflector 14 is disposed in the conductor tube portion 7, but the present invention is not limited to this, and a plurality of reflectors may be disposed. For example, a small reflector may be prepared in addition to the reflector 14, and the reflection surface thereof may be provided in a state of facing the reflection surface 14 a of the reflector 14. Then, the light incident on the reflecting surface of the small reflector can be reflected to the reflector 14 and extracted as parallel light. As a result, the utilization efficiency of the emitted light of the lamp unit 6 can be increased, and much of the emitted light can be efficiently emitted in a certain direction.

(projector)
Next, an embodiment of a projector according to the present invention will be described with reference to FIG. As shown in FIG. 5, the projector 500 includes a light source device 550, liquid crystal light valves (image forming devices) 551 a, 551 b, 551 c, a cross dichroic prism 552, and a projection lens (projection device) 553. The light source device 550 is an application of the light source device of the present invention, and includes a microwave excitation lamp 501, a reflector 502, a filter 503, a lens array 504, a polarization conversion element 505, and a condenser lens 506. Light emitted from the light source device 550 enters the liquid crystal light valves 551a to 551c through the dichroic mirrors 507 and 508, the relay optical system 509, and the like.

  The dichroic mirrors 507 and 508 are formed, for example, by laminating a dielectric multilayer film on the glass surface. As a result, colored light in a predetermined wavelength band is selectively reflected, and colored light in other wavelength bands is transmitted. For example, among the light source light emitted from the light source device 550, the red light La passes through the dichroic mirror 507, and the green light Lb and the blue light Lc are reflected by the dichroic mirror 507. Of the green light Lb and blue light Lc reflected by the dichroic mirror 507, the blue light Lc passes through the dichroic mirror 508, and the green light Lb reflects by the dichroic mirror 508.

  The red light La transmitted through the dichroic mirror 507 is reflected by the reflection mirror, enters the liquid crystal light valve 551a for red light through the collimating lens. The green light Lb reflected by the dichroic mirror 508 enters the liquid crystal light valve 551b for green light through the collimating lens. The blue light Lc that has passed through the dichroic mirror 508 enters the liquid crystal light valve 551c for blue light via the relay optical system 509.

  The cross dichroic prism 552 has a structure in which a triangular prism is bonded, a mirror surface that reflects red light La and transmits green light Lb on its inner surface, and a mirror surface that reflects blue light Lc and transmits green light. Are formed orthogonal to each other. The red light La, the green light Lb, and the blue light Lc are selectively reflected or transmitted by these mirror surfaces and emitted to the same side. As a result, the three color lights are superposed to become combined light. The combined light is enlarged and projected onto the screen 560 by the projection lens 553. As a result, a color display image can be obtained.

  Since the projector 500 as described above includes the light source device 550 to which the light source device of the present invention is applied, the projector 500 has a low power consumption. Further, the leaked radio wave can be reduced by the light source device 550, and the high-quality projector 500 with excellent reliability is obtained.

  In the above-described embodiment, an example in which a transmissive liquid crystal light valve is used as the image forming apparatus has been described. However, a reflective liquid crystal light valve may be used. In that case, the optical system is appropriately changed to an optical system suitable for using a reflective liquid crystal light valve. It is also possible to use an image forming apparatus other than the liquid crystal light valve. For example, an image forming apparatus other than a liquid crystal light valve such as a digital mirror device may be used.

  Further, the light source device of the present invention may be applied as a light source of a projector for digital signage. Further, it can be applied as a light source of an ultraviolet lamp having a cleaning action or a modification effect by ultraviolet rays.

DESCRIPTION OF SYMBOLS 1 ... Light source device, 2 ... Microwave power supply, 3 ... Microwave transmission line, 4A ... 1st connector, 4B ... 2nd connector, 5A ... Impedance keeper part, 5B ... Impedance matching part, 5C ... Resonance part, 6 ... Lamp Part 7: Conductor tube part 7b Inner surface 7c Metal piece (convex part) 8A Center conductor 8B Center conductor 11A, 11B Electrode 12 Microwave lamp 13 Case 16 Arc tube, 18 ... coil, 21A ... center conductor, 21B ... center conductor, 51 ... short member, 500 ... projector

Claims (10)

A housing for a microwave lamp, comprising: a conductor tube portion at least one end of which is an open end; a center conductor disposed along the center axis of the conductor tube portion; and a connector connected to one end of the center conductor. Body,
When the wavelength of the microwave is λg, n is an integer of 0 or more, and m is a natural number,
The central conductor has an arc tube mounting portion at a position 2n times λg / 4 from the opening end in the central axis direction,
The conductor tube portion has a length in the central axis direction that is m times longer than λg / 4, a resonance portion that resonates a TEM mode microwave, and a length in the central axis direction that is m times longer than λg / 4. A matching unit that performs impedance matching between the resonating unit and the connector; an impedance keeper unit that has a length in the central axis direction that is m times λg / 16 and is provided between the connector and the matching unit; Have
The inner diameter of the matching part is reduced from the resonance part side toward the impedance keeper part side,
On the inner surface of the conductor tube portion, a convex portion that determines the resonance length of the microwave is provided,
The convex portion is provided at a position n times λg / 4 from the opening end when m is an even number, and provided at a boundary position between the resonance portion and the impedance keeper portion when m is an odd number. A housing for a microwave lamp, characterized in that A conductor tube part having at least one open end; a center conductor disposed along a central axis of the conductor tube part; a connector connected to one end of the center conductor; the resonance part and the center conductor; A housing for a microwave lamp comprising:
When the wavelength of the microwave is λg, n is an integer of 0 or more, and m is a natural number,
When the wavelength of the microwave is λg, n is an integer of 0 or more, and m is a natural number,
The central conductor has an arc tube mounting portion at a position 2n + 1 times λg / 4 from the opening end in the central axis direction,
The conductor tube portion has a length in the central axis direction that is m times longer than λg / 4, a resonance portion that resonates a TEM mode microwave, and a length in the central axis direction that is m times longer than λg / 4. A matching unit that performs impedance matching between the resonating unit and the connector; an impedance keeper unit that has a length in the central axis direction that is m times λg / 16 and is provided between the connector and the matching unit; Have
The inner diameter of the matching part is reduced from the resonance part side toward the impedance keeper part side,
On the inner surface of the conductor tube portion, a convex portion that determines the resonance length of the microwave is provided,
The convex portion is provided at a position n times λg / 4 from the opening end when m is an even number, and provided at a boundary position between the resonance portion and the impedance keeper portion when m is an odd number. A housing for a microwave lamp, characterized in that   The casing for a microwave lamp according to claim 1 or 2, wherein the inner surface of the conductor tube portion has an exponential shape. The exponential shape has a length λg / 2, the characteristic impedance immediately before introduction of the microwave is Z ₀ , the impedance of the plasma portion is Z _L , the inner diameter of the conductor tube portion is D, the outer shape of the central conductor d, where the dielectric constant in the conductor tube portion is ε, a = (λg / 2) / log (Z _L / Z ₀ ), the change of the coaxial impedance with respect to the length (x) is Z (x) = Z 4. The microwave lamp housing according to claim 3, wherein the curve satisfies a relationship of ₀ · EXP (−x / a) and Z (x) = 138 / √ε · log (D / d). .   The case for a microwave lamp according to any one of claims 1 to 4, wherein a reflector is provided inside the conductive tube portion.   The casing for a microwave lamp according to any one of claims 1 to 5, wherein a coil is externally mounted on the central conductor, or a stub structure is provided by providing irregularities on the central conductor.   The casing for a microwave lamp according to claim 1 or 2, wherein the concavo-convex portion is a pair of metal pieces arranged to face each other via a central axis of the conductor tube portion. A housing for a microwave lamp according to any one of claims 1 to 7,
A microwave lamp comprising: an arc tube in which a luminescent material excited by microwaves is enclosed and attached in the housing. A microwave lamp according to claim 8;
A microwave power source for generating microwaves;
A light source device comprising: a microwave transmission line for transmitting a microwave generated in the microwave power source to the microwave lamp.   A projector comprising the light source device according to claim 9.

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