JP2001202923A - Resonator for electrodeless lamp and light source apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small, lightweight, and high-efficiency resonator for an electrodeless lamp and a light source apparatus using the same. SOLUTION: The light source apparatus is composed of a high-frequency power supply 9, first high-frequency transmission line 7a connected to a high-frequency power supply 9, matching circuit 8 connected to the first high frequency transmission line 7a, second high-frequency transmission line 7b connected to the matching circuit 8, resonator 51 for electrodeless lamp connected to the second high-frequency transmission line 7b, and electrodeless lamp 5 housed in the resonator 51 for the electrodeless lamp. The resonator 51 for the electrodeless lamp consists of a hollow cylindrical grounding conductor 1, a hollow cylindrical dielectric 2 disposed in the interior of the grounding conductor 1, and a signal line 3 disposed on an inner wall of the dielectric substance 2. An approximately center portion of a resonance length of the signal line 3 is set as a feed point 31, and high-frequency electromagnetic waves are fed. The electrodeless lamp 5 is housed in a lamp housing portion 6, consisting of a hollow portion of the dielectric substance 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a high-frequency resonator used for an electrodeless lamp (hereinafter referred to as "resonator for an electrodeless lamp") and a light source device using the resonator for an electrodeless lamp.

[0002]

2. Description of the Related Art Electrodeless lamps are used in projector light sources and the like. The electrodeless lamp discharges a gas sealed in the electrodeless lamp by applying a predetermined microwave. Therefore, in order to efficiently apply microwaves, a cavity is required. For example, the conventional electrodeless lamp shown in FIG. 5 has a cavity 85 composed of a cylindrical wall surrounded by a side portion 86 and upper and lower ends 84 and 87. Cavity resonator 8
5, the geometric dimensions are determined by the frequency of the microwave energy used and the resonance mode. For example, the _TM010 mode is selected as the resonance mode, and its geometric dimensions are set so as to resonate in this resonance mode. The electric field in the case of the _TM010 mode is almost parallel to the height direction of the cavity. Although the height of the cavity resonator 85 is set to be sufficiently small, for example, about 2.69 cm is absolutely necessary in FIG. The end portion 87 of the cavity resonator 85 needs to have a structure for extracting light emitted from the electrodeless lamp 93 to the outside. For this reason, the end 87 of the cavity resonator 85 allows light such as ultraviolet light or visible light to pass through,
Also, it is constituted by a mesh or a screen having a function of confining microwave energy in the cavity.

[0003] The electrodeless lamp 93 is supported by a stem 91 and is located near the center of the cavity resonator 85. The electrodeless lamp 93 is rotated by the motor 92 via the stem 91. The microwave energy generated by the magnetron 88 is supplied via a waveguide 89 to a coupling slot 90 provided in a part of a side 86 of the cavity resonator 85. Then, the electrodeless lamp 93 is discharged by the electromagnetic field of the microwave resonating in the cavity resonator 85. At this time, the cooling gas is supplied to the electrodeless lamp 9.
3 to cool the electrodeless lamp 93.

[0004]

In a conventional electrodeless lamp as shown in FIG. 5, in a method of supplying microwave energy to the electrodeless lamp, the frequency (ie, wavelength) of the microwave is considered. , The shape and dimensions of the cavity resonator are determined. For example, since the wavelength λ ₀ = 428mm in free space of the microwave 700 MHz (electromagnetic waves), the resonant wavelength λ _0/4 = 107mm. For this reason, it is difficult to reduce the size of the cavity resonator having a waveguide structure in a microwave of a millimeter wave band or less.

[0005] In addition, since the cavity resonator is large in size, the conventional electrodeless lamp has to be relatively large. Further, since a function of confining microwave energy in a cavity is required, the conventional electrodeless lamp needs to be shielded in a closed space using a mesh, a screen, or the like in terms of high frequency. And
As described above, since the conventional electrodeless lamp is relatively large, it is necessary to provide an optical reflecting mirror in order to direct the light output emitted from the electrodeless lamp in a predetermined direction.
For this reason, there has been a problem that the structure of the cavity resonator becomes complicated and the cost increases.

On the other hand, in order to generate strong coupling of microwave energy to the electrodeless lamp, it is preferable that the size of the cavity resonator having the waveguide structure is designed to be considerably small. However, as described above, since the physical dimensions determined by the resonance frequency of the required microwave (λ _0/4) is large, the gap between the dimensions of the cavity resonator of the electrodeless lamp is large, efficient electrodeless lamp It was difficult to emit light.

The present invention has been made in view of the above points, and an object of the present invention is to solve the above-mentioned disadvantages of the prior art and to provide a smaller and lighter resonator for an electrodeless lamp.

It is another object of the present invention to provide a resonator for an electrodeless lamp having a high coupling efficiency between the electrodeless lamp and an electromagnetic field of a high frequency electromagnetic wave such as a microwave.

Still another object of the present invention is to provide a resonator for an electrodeless lamp which can discharge the electrodeless lamp at a lower frequency.

Still another object of the present invention is to provide a resonator for an electrodeless lamp which can reduce the size of the electrodeless lamp.

It is still another object of the present invention to provide a light source device using a smaller, lighter, and more efficient electrodeless lamp.

Still another object of the present invention is to provide a light source device which can be miniaturized to such a degree that an electrodeless lamp can be regarded as a point light source and which does not particularly require an optical reflector in a conventional cavity resonator having a waveguide structure. To provide.

[0013]

In order to achieve the above object, a resonator for an electrodeless lamp according to a first aspect of the present invention has a hollow cylindrical grounding conductor, and is disposed inside the grounding conductor. A hollow cylindrical dielectric having a through hole (through hole) in a radial direction, a signal line disposed on the inner wall of the dielectric with a predetermined high-frequency electromagnetic wave resonance length in a circumferential direction; A ground wire connects one end of the wire and a ground conductor through a through hole.
Further, in the resonator for an electrodeless lamp according to the first aspect of the present invention, a substantially central portion of the resonance length of the signal line is set as a predetermined high-frequency electromagnetic wave feeding point, and the high-frequency electromagnetic wave is fed to this point.
Further, the hollow part of the dielectric is used as an electrodeless lamp housing part, and the electrodeless lamp can be housed here.

That is, in the resonator for an electrodeless lamp according to the first aspect of the present invention, a microstrip line is constituted by the signal line, the hollow cylindrical dielectric and the hollow cylindrical ground conductor. . Thus, "resonant length of the high frequency electromagnetic wave" in the first aspect of the present invention, 1/4 of the length of the wavelength lambda _g of the high frequency electromagnetic wave on a microstrip line,
That is, λ _g / 4. One end of the signal line disposed on the inner wall of the dielectric is short-circuited by the ground wiring, and the other end is open. That is, one-side open, one-side short circuit λ
_{A g} / 4 resonator is formed. An electrodeless lamp housing made of an optical material transparent to a desired wavelength and containing a gas therein is housed in an electrodeless lamp housing portion formed of a dielectric hollow portion.

An electrodeless lamp according to the first aspect of the present invention.
The resonator is open at one end and short-circuited at one end. _g/ 4 resonator microphone
Loss-trip line is used, so ground conductor and signal line
By selecting the dielectric constant of the dielectric sandwiched between,
Compared to a cavity resonator with a wave tube structure, the resonance length of high-frequency electromagnetic waves
Can be shortened. In addition, hollow cylindrical
The cross-trip line surrounds the electrodeless lamp.
Therefore, compared to a parallel plate microstrip line
The effective space occupation area can be reduced. Because of this
A smaller resonator for an electrodeless lamp can be designed.

Furthermore, the resonator for an electrodeless lamp according to the first aspect of the present invention has a structure in which a hollow cylindrical microstrip line surrounds the electrodeless lamp. Improves the coupling efficiency. In particular, since the electric field distribution of the microstrip line becomes stronger at the edge of the metal thin film forming the signal line, the electric field can be more efficiently coupled to the electrodeless lamp. And since the coupling efficiency between the electrodeless lamp and the electromagnetic field of the high-frequency electromagnetic wave is high, compared with the case where a cavity resonator having a waveguide structure is used,
It becomes possible to discharge the electrodeless lamp at a lower frequency.

On the other hand, when compared at the same frequency, the resonator for an electrodeless lamp can be made more compact, so that the electrodeless lamp can also be made smaller. For example, in the case of a microwave having a frequency of about 700 MHz or more, the size of the electrodeless lamp can be reduced to such an extent that it can be regarded as a point light source. Furthermore, it is possible to make the tip of the electrodeless lamp optically open, and resonate the electromagnetic field of the high-frequency electromagnetic wave. Therefore, the optical reflector in the conventional cavity resonator having the waveguide structure is not particularly required.

In the resonator for an electrodeless lamp according to the first aspect of the present invention, another dielectric (second dielectric) may be inserted between the microstrip line and the electrodeless lamp. .

A light source device according to a second aspect of the present invention is an apparatus using the resonator for an electrodeless lamp according to the first aspect of the present invention. That is, the light source device according to the second aspect of the present invention includes a high-frequency power supply that generates a predetermined high-frequency electromagnetic wave,
A first high-frequency transmission line connected to the high-frequency power supply;
A matching circuit connected to the first high-frequency transmission line, a second high-frequency transmission line connected to the matching circuit, a resonator for an electrodeless lamp connected to the second high-frequency transmission line, And an electrodeless lamp housed in a resonator for an electrodeless lamp. Here, the “resonator for an electrodeless lamp” includes, as described in the first aspect of the present invention, a hollow cylindrical ground conductor and a hollow cylinder disposed inside the ground conductor and having a through hole in a radial direction. A shaped dielectric, a signal line disposed on the inner wall of the dielectric with a predetermined high-frequency electromagnetic wave resonance length in a circumferential direction, and one end of the signal line and a ground conductor are connected through a through hole. And a grounding wire connected to it. The center of the resonance length of the signal line of the electrodeless lamp resonator is set as a feeding point, and the high-frequency electromagnetic wave transmitted from the second high-frequency transmission line is fed. The electrodeless lamp is housed in the dielectric hollow portion of the electrodeless lamp resonator.

The high-frequency power supply used in the light source device according to the second aspect of the present invention may be any high-frequency power supply as long as it generates a high-frequency electromagnetic wave such as a microwave. Are preferred. For example, a high frequency power supply using a microwave monolithic integrated circuit (MMIC) or the like can be used. Further, as the first and second high-frequency transmission lines used in the light source device according to the second feature of the present invention, various high-frequency transmission lines such as a waveguide, a coaxial cable, and a strip line can be adopted. However, for miniaturization, a coaxial cable or a strip line is preferable. For example, when the second high-frequency transmission line is formed of a coaxial cable, the center conductor of the coaxial cable may be connected to the power supply point of the signal line of the electrodeless lamp resonator by soldering or the like.

The resonator for the electrodeless lamp used in the light source device according to the second feature of the present invention uses a λ _g / 4 resonator microstrip line that is open on one side and short-circuited on one side. Therefore, by selecting the dielectric constant of the dielectric sandwiched between the ground conductor and the signal line, it is possible to shorten the resonance length as compared with a cavity resonator having a waveguide structure. Furthermore,
Since the hollow cylindrical microstrip line surrounds the electrodeless lamp, the effective space occupation area can be made smaller than that of the parallel plate microstrip line, and a smaller electrodeless lamp resonator can be designed. Becomes

Further, the resonator for an electrodeless lamp used in the light source device according to the second aspect of the present invention has a structure in which a hollow cylindrical microstrip line surrounds the electrodeless lamp. High coupling efficiency with high-frequency electromagnetic fields. In particular, since the electric field distribution of the microstrip line is strong at the edge of the metal thin film forming the signal line, the electric field can be more efficiently coupled by the electrodeless lamp. For this reason, it becomes possible to discharge the electrodeless lamp at a lower frequency than in the case where a cavity resonator having a waveguide structure is used.

On the other hand, when compared at the same frequency, the size of the resonator for an electrodeless lamp can be further reduced, so that the electrodeless lamp can be reduced in size to such an extent that it can be regarded as a point light source. Further, it is possible to resonate a high-frequency electromagnetic field such as a microwave by setting the tip of the electrodeless lamp in an optically open state. Therefore, the optical reflector in the conventional cavity resonator having the waveguide structure is not particularly required.

In the resonator for an electrodeless lamp used in the light source device according to the second aspect of the present invention, another dielectric (the second electrode) is provided between the microstrip line and the electrodeless lamp.
(A dielectric) may be inserted.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing the first and second embodiments of the present invention, a basic design of a resonator for an electrodeless lamp used in a light source device of the present invention will be described.

(Basic Design) Here, a schematic diagram of a parallel plate type microstrip line ("two-dimensional microstrip line") shown in FIG. 4 is used to describe a resonator for an electrodeless lamp used in the light source device of the present invention. The basic design will be described. As will be apparent from the following description of the first and second embodiments of the present invention, the resonator for an electrodeless lamp used in the light source device of the present invention has a hollow cylindrical ground conductor and a hollow cylindrical dielectric. This is a "three-dimensional microstrip line" constituted by a body and a signal line provided on an inner circumferential circle of the hollow cylindrical dielectric. However, the simplified calculation for the two-dimensional microstrip line requires some correction for the three-dimensional microstrip line, but for the spatial dimensions, an approximate calculation that gives a rough indication. It is possible to think.

In this basic design, the frequency of the high-frequency electromagnetic wave to be fed is, for example, 700 MHz.
In the case of the 700 MHz microwave, the dimensions of each component and a calculation example will be described as follows.

The parallel plate type microstrip line shown in FIG. 4 includes a dielectric 82, a signal line 83 disposed on the surface of the dielectric 82, and a ground conductor 81 disposed on the back of the dielectric 82. ing. In this parallel plate type microstrip line, the dielectric 82 is assumed to be alumina (relative permittivity ε _r = 9.6), and its thickness h = 3.2 mm.
And The signal line 83 on the dielectric 82 has a width W = 3.
2 mm and thickness t = 0.032 mm.

The characteristic impedance Z _{c of the} microstrip line and the resonance length λ _g / 4 of the microwave are such that the characteristic impedance in free space (air: relative permittivity εr = 1) is Z ₀ , and the wavelength in free space is λ _0. Then, using the effective relative permittivity ε _eff , Z _c = Z ₀ / (ε _eff ) ^1/2 ... (1) λ _g = λ ₀ / (ε _eff ) ^1/2 . It is. Therefore, if the characteristic impedance Z ₀ of free space (air) and the effective relative permittivity ε _eff are obtained, the characteristic impedance Z _c of this microstrip line and the wavelength λ _g on the microstrip line are obtained. That is, the characteristic impedance Z _c of the microstrip line, the wavelength lambda _g of the microstrip line, the approximate value is calculated from the following equation.

[0030]

Ε _eff = (ε _r +1) / 2 + (ε _r −1) (1 + 10 h / w) ^−1/2/2 (3)

The effective signal line width W of the microstrip line
₀ = W + ΔW is the apparent line width expansion (effective fringe width) ΔW

ΔW = (t / h) ln (4e ((t / h) ² + π ⁻² (w / t + 1.1) ⁻² ) ^−1/2 ) (4) This effective signal line width W ₀
The used, equivalent aspect ratio A _1, A ₂ and 8h / W ₀ = A _1, if defined in _{... (5) A 1/2} = A 2 ... (6), Z 0 is

Equation 3] can be obtained by _{Z 0 = 30ln (1 + A} 2 (A 1 + (A 1 2 + π 2) 1/2)) ... (7). Therefore, when each numerical example is substituted into the above equation, the effective fringe width ΔW = 0.0707, the effective signal line width W ₀ = 3.2707, the characteristic impedance Z _{0 of the} microstrip line = 125Ω, and the effective relative permittivity ε _eff
= 6.6 is obtained.

Since the wavelength λ ₀ is 428 mm in the free space of the electromagnetic wave of 700 MHz, the characteristic impedance Zc of the resonator for the electrodeless lamp using the λ _g / 4 resonator microstrip line with one side open and one side short-circuited, and the resonance The length λ _g / 4 is respectively

Z _c = 125 / (6.6) ^1/2 = 48.6Ω (8) λ _g = 428 / (6.6) ^1/2 = 166.6 mm (9) λ _g / 4 = 41.7 mm (10) In other words, when the characteristic impedance is around 50Ω and the microstrip line length is 41.7 mm, 700 MHz
It turns out that it resonates.

The resonator for an electrodeless lamp used in the light source device of the present invention is provided on a hollow cylindrical ground conductor, a hollow cylindrical dielectric, and an inner circumferential circle of the hollow cylindrical dielectric. And a three-dimensional microstrip line constituted by the signal lines. Therefore, strictly, a slight correction is required for the design of the three-dimensional microstrip line. However, the line length of the two-dimensional microstrip line is 41.7 mm, which is 41.7 / π = 13.3 (11) if this is regarded as the circumferential length. About 3 mm. Actually, it is necessary to provide a gap of 3 to 4 mm between both ends of the signal line 3 which has circulated on the inner circumference of the hollow cylindrical dielectric. Therefore, in reality, it is necessary to make the diameter slightly larger and to ensure a gap between both ends of the signal line 3. Therefore, the inner diameter (diameter) of the hollow cylindrical dielectric is about 14 to 15 mm. The size of about 14 to 15 mm in diameter is a very convenient size for inserting a small electrodeless lamp.

As can be seen from the calculation formulas, the characteristic impedance Z _{c of} the microstrip line and the wavelength of the high-frequency electromagnetic wave on the microstrip line are changed by changing the dielectric constant of the dielectric and the physical dimensions of the dielectric and the microstrip line. it is also possible to adjust the λ _g.

Under the above basic design, the first and second embodiments of the present invention will be described. In the following description of the drawings used for describing the first and second embodiments, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the plane dimension, the ratio of the thickness of each layer, and the like are different from actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. In addition, it is needless to say that the drawings include portions having different dimensional relationships and ratios.

(First Embodiment) As shown in FIG. 1, a light source device according to a first embodiment of the present invention comprises a high-frequency power supply 9 for generating a predetermined high-frequency electromagnetic wave (microwave), 9 connected to the first high-frequency transmission line (first
Coaxial cable) 7a and the first high-frequency transmission line 7
a, and a second high-frequency transmission line (second coaxial cable) 7b connected to the matching circuit 8
And an electrodeless lamp resonator 51 connected to the second high-frequency transmission line 7b; and an electrodeless lamp resonator 51.
And the electrodeless lamp 5 housed in the housing.

Here, as shown in FIGS. 1 and 2, the resonator 51 for an electrodeless lamp comprises a hollow cylindrical grounding conductor 1;
A through hole 4 is disposed inside the ground conductor 1 and extends in the radial direction.
1, a signal line 3 arranged on the inner wall of the dielectric 2 with a predetermined high-frequency electromagnetic wave resonance length in the circumferential direction, and one end of the signal line 3 And a ground wiring 4 for connecting the ground conductor 1 to the ground conductor 1 through a through hole 41. A substantially central portion of the resonance length of the signal line 3 of the electrodeless lamp resonator 51 is used as a feeding point 31 to feed a high-frequency electromagnetic wave transmitted from the second high-frequency transmission line. The electrodeless lamp 5 is housed in a lamp housing 6 formed of a hollow portion of the dielectric 2 of the electrodeless lamp resonator 51.

That is, the resonator 51 for an electrodeless lamp according to the first embodiment of the present invention comprises a signal line 3, a hollow cylindrical dielectric 2, and a hollow cylindrical grounding conductor 1 having a predetermined characteristic impedance. And a microstrip line having the following. The signal line 3 of this microstrip line is
As shown in FIG. 1, one end is short-circuited by a ground wiring 4, and the other end is open. That is, a microstrip line having one side open and one side short-circuited is formed. The length of the signal line 3 of the microstrip line is chosen to 1/4 of the length of the wavelength lambda _g of the microstrip line. That is, the electrodeless lamp resonator 51 according to the first embodiment of the present invention has a single-sided open and a single-sided short-circuited λ _g / 4.
It is a resonator.

As already described, a two-dimensional microstrip line with a characteristic impedance of around 50Ω has a signal line length of λ _g /4=41.7 mm and a 700M
It turns out that it resonates with the microwave of Hz. Strictly, a slight correction is required for the three-dimensional microstrip line shown in FIG. However, when the line length of the two-dimensional microstrip line is 41.7 mm, the diameter of the inner peripheral surface of the hollow cylindrical dielectric 2 shown in FIG. 1 is about 13.3 mm. Since one side is open and one side is short-circuited, in practice, it is necessary to provide a gap of 3 to 4 mm between both ends of the signal line 3 that has circulated on the inner circumference of the hollow cylindrical dielectric. For this reason, the inner diameter (diameter) of the hollow cylindrical dielectric 2 shown in FIG. 1 is set to about 14 to 15 mm.
Since the signal line 3 is arranged so as to be substantially wound around the electrodeless lamp 5, high-frequency energy can be applied to the electrodeless lamp 5 very effectively.

A center conductor 71 of a second high-frequency transmission line (second coaxial cable) 7b is electrically connected to a feeding point 31 provided near the center of the signal line 3 from outside by soldering or the like. ing. That is, high-frequency electromagnetic waves are supplied from the coaxial cable 7b, which is the second high-frequency transmission line, via the power supply point 31 electrically connected by the solder or the like. As shown in FIG. 1, the coaxial cable 7 b has a configuration in which a center conductor 71 is covered with an insulator 74, and the outer periphery of the insulator 74 is covered with an outer conductor 72. Further, the outer conductor 72 is covered with a jacket 73.

The second high-frequency transmission line used in the light source device according to the first embodiment of the present invention may be a waveguide, two parallel lines, a strip line, a microstrip line, a coplanar conductor, in addition to a coaxial cable. Various high-frequency transmission lines such as a wave line (coplanar wave guide) can be adopted. However, at frequencies below the millimeter wave band, the waveguide inherently has relatively large dimensions, which is not desirable for miniaturization. At high frequencies above the submillimeter wave band, the size of the waveguide is reduced, so that even when a waveguide is used, the increase in volume (capacity) may not be a concern.

The matching circuit 8 shown in FIG.
The entire impedance of the second high-frequency transmission line (second coaxial cable) 7b and the electrodeless lamp resonator 51 on the more distal end side is adjusted, and high-frequency electromagnetic waves are supplied to the electrodeless lamp resonator 51 most efficiently. To be adjusted.

As the high-frequency power source 9, various devices can be employed as long as they generate microwaves of 300 MHz or more.
For miniaturization, a transistor power supply using a MOSFET, a high electron mobility transistor (HEMT), a heterojunction bipolar transistor (HBT), an electrostatic dielectric transistor (SIT), or the like is preferable. Magnetron (2.
45 GHz) may be used, but is not suitable for miniaturization. 1
At a high frequency of GHz or more, a high frequency power supply in which a transistor amplifier circuit is integrated on the same chip by an MMIC can be used. The power of the microwaves varies from several tens of watts to about 200 watts, depending on the application. As the frequency increases, the size of the electrodeless lamp resonator 51 decreases, and the size of the electrodeless lamp 5 also decreases. Therefore, the required microwave power can be reduced as the frequency becomes higher.

The resonator 51 for an electrodeless lamp according to the first embodiment of the present invention has a high coupling efficiency between the electrodeless lamp and the electromagnetic field of a high-frequency electromagnetic wave. The electrodeless lamp can be discharged at a lower frequency as compared with the case where the electrodeless lamp is used. Therefore, if the miniaturization is sacrificed to some extent, a high frequency of about 100 MHz or 100 MHz or less can be adopted.

The first high-frequency transmission line 7a used in the light source device according to the first embodiment of the present invention is similar to the second high-frequency transmission line, except for a coaxial cable, a waveguide, a strip line, and a micro-wave transmission line. Various high-frequency transmission lines such as a strip line and a coplanar waveguide line can be adopted. Furthermore, a high-frequency power supply 9, a first high-frequency transmission line 7a, and a matching circuit 8
Can be integrated on the same semiconductor substrate to form a small and highly efficient light source device with an MMIC structure.

The ground conductor 1 shown in FIG. 1 is a metal shielding plate having a central portion formed in a circular shape and serving also as a radiator. Then, as is apparent from the cross-sectional view along the axial direction shown in FIG. Ground conductor 1
A dielectric member 2 having a high dielectric constant and having a central portion formed in a circular shape is concentrically arranged in the hollowed inner diameter portion with a certain thickness. FIG. 2B shows a side view of the dielectric 2. The dielectric 2 is fitted in a hollow part of the ground conductor 1 that is open on one side. As the dielectric 2, alumina (Al
₂ O ₃ ), aluminum nitride (AlN), beryllia (Be
Ceramics having heat resistance such as O) and having excellent heat conduction properties are preferred.

The electrodeless lamp 5 has a bulb made of an optical material (glass) transparent to desired light. A gas containing various metals, metal compounds, and the like may be sealed in the tube depending on the application. For example, the electrodeless lamp 5 that emits visible light includes mercury (Hg), sodium (Na), thallium (Tl), indium (In),
Scandium (Sc), Thorium (Th), Tin (S
n) or a rare gas such as xenon (Xe) gas at a pressure of several kPa together with these halides. In the electrodeless lamp 5 that emits ultraviolet light,
The material of the electrodeless lamp 5 is fused quartz (SiO ₂ ), sapphire (Al ₂ O ₃ ), calcium fluoride (CaF ₂ ),
Magnesium fluoride (MgF ₂ ), lithium fluoride (L
What has good transmittance | permeability of ultraviolet rays, such as iF), should just be used. In particular, the use of fused quartz with few metal impurities is suitable from the viewpoint of workability and the like. As the filling material, mercury (Hg), zinc (Zn), cadmium (Cd), selenium (Se), arsenic (As), or a halide thereof,
Both may be filled with a rare gas such as xenon (Xe) gas. Alternatively, iodine (I ₂ ) gas, hydrogen (H ₂ ) gas, deuterium (D ₂ ) gas, xenon (Xe) gas, or the like may be filled. The length of the electrodeless lamp 5 varies depending on the application.

As is apparent from the above-described approximate calculation, the tube diameter of the electrodeless lamp 5 is 1 for a 700 MHz microwave.
It is about 3 mm. However, if a higher frequency microwave is used, the tube diameter of the electrodeless lamp 5 can of course be further reduced.

As described above, according to the first embodiment of the present invention, the size of the electrodeless lamp 5 can be reduced to such an extent that it can be regarded as a point light source. Further, as shown in FIG. 2, it is possible to make the tip of the electrodeless lamp 5 optically open and resonate a high-frequency electromagnetic field such as a microwave. Therefore, light can be efficiently emitted in the left direction in FIG. 2 without using an optical reflecting mirror.

The Q of the resonator 51 for an electrodeless lamp according to the first embodiment of the present invention is
Digits and 3 to 4 digits are obtained in the matching state.

(Second Embodiment) As shown in FIG. 3, a resonator 52 for an electrodeless lamp according to a second embodiment of the present invention has a hollow cylindrical ground conductor 1 and an inner portion of the ground conductor 1. And a hollow cylindrical first dielectric 21 having a through hole 41 in the radial direction, and a signal arranged on the inner wall of the first dielectric 21 so as to have a predetermined high-frequency electromagnetic wave resonance length in the circumferential direction. It comprises a line 3 and a ground wire 4 for connecting one end of the signal line 3 to the ground conductor 1 via a through hole 41. A substantially central portion of the resonance length of the signal line 3 of the electrodeless lamp resonator 52 is used as a feeding point 31 for feeding high-frequency electromagnetic waves transmitted from the second high-frequency transmission line. In the resonator 52 for an electrodeless lamp according to the second embodiment of the present invention, a hollow cylindrical second dielectric 22 is inserted further inside the signal line 3. The second dielectric 22 may have a different dielectric constant from the first dielectric 21. As the first dielectric 21, a ceramic such as alumina may be used. Second dielectric 2
As 2, for example, macol or the like, which can be easily processed, can be used. The electrodeless lamp 5 is a resonator 5 for an electrodeless lamp.
The second dielectric 22 is housed in the lamp housing 6 formed of a hollow portion.

That is, the resonator 52 for an electrodeless lamp according to the second embodiment of the present invention comprises the signal line 3, the hollow cylindrical first dielectric 21 and the same as the first embodiment of the present invention. The hollow cylindrical ground conductor 1 constitutes a microstrip line having a predetermined characteristic impedance. As shown in FIG. 3, one end of the signal line 3 of the microstrip line is short-circuited by the ground wiring 4 and the other end is opened to form a one-side open, one-side short-circuited microstrip line. I have. The length of the signal line 3 of the microstrip line is chosen to 1/4 of the length of the wavelength lambda _g of the microstrip line. That is, the resonator 52 for an electrodeless lamp according to the second embodiment of the present invention includes the first resonator.
A λ _g / 4 resonator with one side open and one side short-circuited as in the embodiment of FIG.

As already described, a two-dimensional microstrip line with a characteristic impedance of around 50Ω has a signal line length of λ _g /4=41.7 mm and 700M
It turns out that it resonates at Hz. Strictly, a slight correction is required for the three-dimensional microstrip line shown in FIG. However, the fact that the line length of the two-dimensional microstrip line is 41.7 mm means that the diameter of the inner peripheral surface of the hollow cylindrical first dielectric 21 shown in FIG.
mm. As described above, the first dielectric 21
The distance between the two ends of the signal line 3 that has circulated on the inner circumference of
Since it is necessary to open the first dielectric 21 mm, the inner diameter (diameter) of the first dielectric 21 is about 14 to 15 mm. Accordingly, the outer diameter (diameter) of the second dielectric 22 is determined in consideration of the thickness of the signal line 3.
For example, a size of about 12 to 14.7 mm may be selected. The tube diameter of the electrodeless lamp 5 is determined in consideration of the thickness of the second dielectric 22. For example,
At 700 MHz, it may be selected to be about 8 to 13 mm. The fact that the frequency can be further reduced by increasing the frequency is the same as in the first embodiment.

Although not shown, the high-frequency power supply 9 and the first high-frequency transmission connected to the high-frequency power supply 9 are similar to the light source device according to the first embodiment of the present invention shown in FIG. Needless to say, it further includes a line (first coaxial cable) 7a and a matching circuit 8 connected to the first high-frequency transmission line 7a. Then, a second high-frequency transmission line (second
7b is connected to the matching circuit 8.

When the structure of the electrodeless lamp resonator 52 according to the second embodiment of the present invention shown in FIG. 3 is used, the electric field strength that becomes strong at the edge of the signal line 3 of the microstrip line is reduced.
It can be controlled by the second dielectric 22.

When the structure of the electrodeless lamp resonator 52 according to the second embodiment of the present invention shown in FIG. 3 is used, the thermal conductivity of heat generated from the electrodeless lamp is reduced by the second dielectric 2.
It is possible to increase by 2. Further, the second dielectric 22
Can contribute to the explosion protection of the electrodeless lamp 5.

[0057]

As described above, according to the present invention, a smaller and lighter resonator for an electrodeless lamp can be provided.

Further, according to the present invention, it is possible to provide a resonator for an electrodeless lamp having a high coupling efficiency between the electrodeless lamp and an electromagnetic field of a high-frequency electromagnetic wave.

Further, according to the present invention, it is possible to provide an electrodeless lamp resonator capable of discharging the electrodeless lamp at a lower frequency.

Further, according to the present invention, it is possible to provide a resonator for an electrodeless lamp which can reduce the size of the electrodeless lamp.

Further, according to the present invention, it is possible to provide a light source device using a smaller, lighter and more efficient electrodeless lamp.

Further, according to the present invention, there is provided a light source device which can be miniaturized to such a degree that an electrodeless lamp can be regarded as a point light source, and does not particularly require an optical reflecting mirror in a conventional cavity resonator having a waveguide structure. can do.

[Brief description of the drawings]

FIG. 1 is a sectional view in a direction perpendicular to an axial direction of a resonator for a cylindrical electrodeless lamp according to a second embodiment of the present invention.

2A is a cross-sectional view of the cylindrical electrodeless lamp resonator shown in FIG. 1 along the axial direction, and FIG. 2B is a coupling relationship between a dielectric and a high-frequency transmission line. FIG.

FIG. 3A is a cross-sectional view in a direction perpendicular to the axial direction of a cylindrical electrodeless lamp resonator according to a second embodiment of the present invention, and FIG. It is sectional drawing along the axial direction.

FIG. 4 is a bird's-eye view showing a structure of a microstrip line.

FIG. 5 is a bird's-eye view showing a light source device using a conventional electrodeless lamp.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 ground conductor 2 dielectric 3 signal wire 4 ground wiring 5 electrodeless lamp 6 lamp housing 7 a first high-frequency transmission line (first coaxial cable) 7 b second high-frequency transmission line (second coaxial cable) 8 matching Circuit 9 High-frequency power supply 21 First dielectric 22 Second dielectric 31 Feeding point 41 Through hole 51, 52 Resonator for electrodeless lamp 71 Center conductor 72 External conductor 73 Jacket 74 Insulator 81 Ground conductor 82 Dielectric 83 Signal line 84, 87 end portion 85 cavity resonator 86 side portion 88 magnetron 89 waveguide 90 coupling slot 91 stem 92 motor 93 electrodeless lamp

Claims (2)

[Claims] A hollow cylindrical grounding conductor, a hollow cylindrical dielectric disposed inside the grounding conductor and having a through hole in a radial direction, and a predetermined circumferentially extending inner wall provided on the dielectric. A signal line arranged with a resonance length of a high-frequency electromagnetic wave, and a ground wire connecting one end of the signal line and the ground conductor through the through hole; A resonator for an electrodeless lamp, wherein the predetermined high-frequency electromagnetic wave is supplied to the signal line at a substantially central portion, and the hollow portion of the dielectric is an electrodeless lamp housing. 2. A high-frequency power supply for generating a predetermined high-frequency electromagnetic wave; a first high-frequency transmission line connected to the high-frequency power supply; a matching circuit connected to the first high-frequency transmission line; A second high-frequency transmission line connected thereto, a hollow cylindrical grounding conductor, a hollow cylindrical dielectric disposed inside the grounding conductor and having a through hole in a radial direction, and a circle formed on an inner wall of the dielectric. A non-electrode comprising a signal line arranged with a predetermined high-frequency electromagnetic wave resonance length in the circumferential direction, and a ground wiring connecting one end of the signal line and the ground conductor through the through hole. A lamp resonator, and an electrodeless lamp housed in a hollow portion of the dielectric, and a high-frequency electromagnetic wave transmitted from the second high-frequency transmission line is supplied at a substantially central portion of the resonance length. Features Light source device for.