JP2003022785A - Microwave electrodeless discharge lamp device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve luminescence efficiency by raising mechanical strength of a cavity resonator. SOLUTION: Electric energy supplied from a power supply 1 is converted into microwave energy by a magnetron 2, and transmitted to the cavity resonator 4 through an wave guide 3. The cavity resonator 4 is formed in a cylinder form of a wire net, and a rectangular joint window 4a is opened at the joint part with the wave guide 3 in the bottom face. Moreover, a lamp bulb 5 supported by a cylindrical supporting component 5a is arranged near the center part in the internal space of the cavity resonator 4. Since a disk-like dielectric 6, which has the diameter of the approximately equal diameter to the diameter of the cavity resonator 4, is arranged in the internal space of the cavity resonator 4, the size of the cavity resonator 4 can be made small by shortening the wavelength of microwave during transmission inside of the dielectric 6. Consequently, the miniaturization noises the mechanical strength of the cavity resonator 4, the deformation of the cavity resonator 4 is prevented, and improvement in luminescence efficiency can be achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave electrodeless discharge lamp device in which a lamp bulb in which a light-emitting substance which emits light by discharge by microwaves is sealed is arranged in an internal space of a cavity resonator.

[0002]

2. Description of the Related Art An electrodeless discharge lamp is generally expected to have a long life because there are no electrodes inside the lamp bulb. Conventionally, a microwave electrodeless discharge lamp device for lighting such an electrodeless discharge lamp by microwave has been provided (for example, JP-A-59-86153 and JP-A-7-451).
No. 04, etc.).

In the conventional microwave electrodeless discharge lamp device,
It is formed of a wire mesh having an appropriate aperture ratio, is formed into a disc shape by an insulating member in the internal space of the cavity resonator that is opaque to microwaves and substantially transparent to light. As a result, a reflecting mirror that is opaque to microwaves and light is inserted, and this reflecting mirror controls the light distribution of the light emitted by the lamp bulb.

[0004]

However, when the cavity resonator is formed by using the wire mesh as in the above-mentioned conventional example, the opening of the wire mesh is used to extract the light emitted from the lamp bulb from the internal space of the cavity resonator to the outside. There is a problem that the mechanical strength of the cavity resonator is weakened because it is necessary to increase the rate. When the mechanical strength of the cavity resonator is weak in this way, the cavity resonator is deformed by the impact of heat generated by the light emission of the lamp bulb and vibration applied from the outside, and the resonance frequency (resonance wavelength) of the internal space changes from the design value. As a result, the energy coupling with the lamp bulb is deteriorated, and as a result, the energy supplied to the lamp bulb is reduced and the luminous efficiency is reduced.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a microwave electrodeless discharge lamp device in which the mechanical strength of the cavity resonator is increased to improve the luminous efficiency. To provide.

[0006]

In order to achieve the above object, the invention of claim 1 is a microwave generating means for generating a microwave and a microwave generating means having at least a part capable of transmitting light. The cavity resonance is provided with a cavity resonator in which the microwave generated by the means is supplied to the internal space, and a lamp bulb in which a luminescent substance that discharges and emits light by the microwave is enclosed inside and is arranged in the interior space of the cavity resonator. It is characterized in that a dielectric is arranged at a strong electric field portion in the inner space of the container. Generally, when an electromagnetic wave having a wavelength λ0 in a vacuum propagates in a dielectric having a relative permittivity ε, the wavelength λ in the dielectric is λ = λ0 / √ε. Therefore, by disposing the dielectric in the strong electric field portion in the internal space of the cavity resonator, the size of the cavity resonator can be reduced by shortening the wavelength of the microwave when propagating in the dielectric. As a result, the mechanical strength of the cavity resonator can be increased by miniaturization, deformation of the cavity resonator can be prevented, and light emission efficiency can be improved.

The invention of claim 2 is characterized in that, in the invention of claim 1, the dielectric itself is held by at least a part of the dielectric in the internal space of the cavity resonator. Since it is not necessary to separately prepare the member, the structure can be simplified and the cost can be reduced.

The invention of claim 3 is characterized in that, in the invention of claim 1 or 2, the thickness of the dielectric is made non-uniform, and the electric field distribution in the internal space of the cavity resonator is varied according to the thickness of the dielectric. It can be controlled and plasma can be generated in the glass bulb with high efficiency.

The invention of claim 4 is the invention of claim 1 or 2 or 3.
In the invention, the dielectric is composed of an assembly of polygonal cylindrical bodies, and the light emitted from the glass bulb passes through the dielectric and is emitted to the outside, so that the luminous efficiency can be improved. .

The invention of claim 5 is characterized in that, in the invention of claim 4, the polygonal cylindrical body is a hexagonal cylindrical body, and the mechanical strength is improved while making the dielectric material lightweight. You can

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, at least a part of the surface of the dielectric is white, and the reflectance of light on the surface of the dielectric is increased to emit light. The efficiency can be further improved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) FIG. 2 shows the overall structure of a microwave electrodeless discharge lamp device of this embodiment. However, in FIG. 2, the structure of the cavity resonator 4, which is the gist of the present invention, is shown in a simplified manner.

As shown in FIG. 2, electric energy supplied from the power source 1 is converted into microwave energy by the magnetron 2 and propagated through the waveguide 3 to the cavity resonator 4. The cavity resonator 4 is formed in a cylindrical shape by a wire mesh, and a rectangular coupling window 4a is opened at the coupling portion with the waveguide 3 on the bottom surface. A lamp bulb 5 supported by a rod-shaped support 5 a is arranged near the center of the internal space of the cavity resonator 4. The lamp bulb 5 is formed in a spherical shape by a translucent member such as glass, and a rare gas and a luminescent substance are enclosed in the inside thereof. Thus, as described in the prior art, by setting the outer dimensions of the cavity resonator 4 and the dimensions of the coupling window 4a to appropriate values according to the frequency of the microwave converted by the magnetron 2, The microwave resonates in the internal space of the container 4, the microwave energy increased by the resonance is supplied to the lamp bulb 5, plasma is generated in the lamp bulb 5, and the plasma emits the luminescent material.

For example, the external dimensions of the cavity resonator 4 that resonates the microwave of frequency 2.45 [GHz] output from the magnetron 2 in the TE ₁₁₁ mode are calculated to have a diameter of 76 [mm] and a height of 184 []. mm], the height dimension is relatively large with respect to the diameter, and the wire diameter of the wire mesh is usually 0.
The dimension of the opening is 1.6 [mm] × 1.
Since the aperture ratio is about 80% at 6 [mm], sufficient mechanical strength cannot be obtained, and there is a risk of deformation due to vibration during transportation.

Therefore, in the present embodiment, as shown in FIG. 1, a disk-shaped dielectric 6 having a diameter substantially equal to the diameter of the cavity resonator 4 is arranged in the internal space of the cavity resonator 4. The dielectric 6 includes, for example, a large number of disk-shaped main portions 6a and a plurality of (three in the present embodiment) rod-shaped support portions 6b that are provided near the periphery of the bottom surface of the main portion 6 at substantially equal intervals. It is integrally formed of crystalline alumina. The tip of each rod-shaped support portion 6b is brought into contact with the inner bottom surface of the cavity resonator 4 so that the main portion 6a has a strong electric field in the internal space of the cavity resonator 4 (near the center where the lamp bulb 5 is disposed). Is located in.

Generally, when an electromagnetic wave having a wavelength λ0 in a vacuum propagates in a dielectric having a relative permittivity ε, the wavelength λ in the dielectric is λ = λ0 / √ε. For example, frequency 2.45 [G
[Hz], the wavelength λ0 in vacuum is about 122
In contrast to [mm], the wavelength λ when propagating in the dielectric is calculated to be about 42 [mm] because the relative permittivity of polycrystalline alumina is about 8.5. That is, if simply considered, the distance can be shortened to about one third by replacing the propagation path of the electromagnetic wave from a vacuum with a dielectric.

Therefore, the thickness of the main portion 6a of the dielectric 6 is about 20 [mm], and the diameter of the lamp bulb 5 is 20 [m].
m] and the size of the coupling window 4a is 60 [mm] × 12 [mm]
In such a case, the height dimension of the cavity resonator 4 is changed from 184 [mm] to 1 due to the wavelength shortening effect when propagating in the dielectric 6.
It can be reduced to about 40 [mm] by about 40 [mm]. As a result, the mechanical strength of the cavity resonator 4 can be increased by downsizing, the deformation of the cavity resonator 4 can be prevented, and the luminous efficiency can be improved. If the reflectance is increased by making the dielectric 6 white, the light emitted from the lamp bulb 5 can be efficiently reflected on the surface of the dielectric 6 to further improve the light emission efficiency. Furthermore, the cavity resonator 4
Since the dielectric 6 itself (main part 6a) is held by the rod-shaped support portion 6b which is at least a part of the dielectric 6 in the internal space of the above, it is not necessary to separately prepare a member for holding the dielectric 6. The advantages are that the structure can be simplified and the cost can be reduced. However, the main portion 6a is composed of a plurality of rod-shaped support portions 6b.
In place of the structure for supporting the main part 6a, the thickness of the main part 6a may be increased and the main part 6a itself may be placed on the bottom surface of the cavity resonator 4. With such a structure, the wavelength is further shortened. By making the cavity resonator 4 smaller,
The mechanical strength can be further improved.

The dielectric 6 may be, for example, quartz glass in addition to polycrystalline alumina, but since the relative permittivity of quartz glass is 3.8, which is lower than that of polycrystalline alumina, the wavelength shortening action is reduced. Therefore, in order to obtain the same effect as polycrystalline alumina, it is necessary to increase the thickness dimension of the dielectric.

(Embodiment 2) This embodiment is characterized in that a cylindrical portion 6c arranged along the inner peripheral surface of a cylindrical cavity resonator 4 is added to a dielectric 6 as shown in FIG. There is.

That is, since the polycrystalline alumina forming the dielectric 6 is a material having a high heat insulating property, it is possible to protect the cavity resonator 4 from the heat generated by the lamp bulb 5 and prevent oxidation of the wire mesh. Further, with the structure in which the cylindrical portion 6c is arranged in the cavity resonator 4 as described above, the peripheral surface of the cavity resonator 4 does not need to be a wire mesh, and therefore the peripheral surface excluding the upper and lower bottom surfaces is formed of a metal plate. By doing so, the mechanical strength of the cavity resonator 4 can be further improved. In this embodiment, since the main portion 6a of the dielectric 6 is held by the cylindrical portion 6c, the rod-shaped holding portion 6b is unnecessary.

(Embodiment 3) In this embodiment, as shown in FIG. 4, a cylindrical portion 6c and the internal space of the cavity resonator 4 below the lamp bulb 5 are filled with a ceramic material such as polycrystalline alumina. The feature is that the filling portion 6d is provided as the dielectric 6.

According to this embodiment, the wavelength can be further shortened as compared with the second embodiment, so that the height dimension of the cavity resonator 4 can be further reduced and the mechanical strength can be improved. If the filling portion 6d is used to support the lamp bulb 5 as shown in FIG. 5, the support 5a is not required and the cost can be reduced.

(Embodiment 4) This embodiment is characterized in that a through hole 6e is formed substantially in the center of the main portion 6a as shown in FIG. 6, and the lamp bulb 5 is arranged inside this through hole 6e. is there.

By providing the through hole 6e at the substantially center of the main portion 6a of the dielectric 6, the thickness becomes non-uniform, and further,
The electric field around the lamp bulb 5 can be controlled by disposing the lamp bulb 5 inside the through hole 6e. Therefore, the microwave energy can be efficiently supplied to the lamp bulb 5 to further improve the light emission efficiency.

(Embodiment 5) When the microwave in the internal space of the cavity resonator 4 is in the TM010 mode, an electric field is generated in the axial direction (height direction) of the cavity resonator 4 so that the cavity resonator 4 is generated. A relatively large electric current flows on the upper and lower surfaces of the upper bottom surface to accelerate the deterioration due to heat.

Therefore, in this embodiment, as shown in FIGS. 7 and 8, the wire netting 4b on the upper and bottom surfaces of the cavity resonator 4 has a so-called honeycomb structure composed of a large number of hexagons, and further, a hexagonal tubular body. Support part 6 having a honeycomb structure composed of an aggregate of
f is provided on one end side (upper end in FIG. 7) of the cylindrical portion 6c to support the wire netting 4b of the cavity resonator 4 from below. Here, the supporting portion 6f of the dielectric 6 is the cavity resonator 4
The honeycomb structure is formed in the same shape and the same size as the honeycomb structure formed on the upper bottom surface.

By adopting such a structure in this embodiment, the light emitted from the lamp bulb 5 is held by the holding portion 6.
Since the amount of light that is blocked by f and directly irradiates the upper bottom of the cavity resonator 4 is reduced, the mechanical strength of the cavity resonator 4 can be improved. The supporting portion 6 of the dielectric 6
It is not necessary for f to support the entire wire mesh 4b of the cavity resonator 4, and a structure for partially supporting it may be used.

(Embodiment 6) This embodiment is characterized in that the dielectric body 6 has a honeycomb structure composed of an assembly of a large number of hexagonal cylindrical bodies as shown in FIG.

Thus, according to the present embodiment, by making the dielectric 6 a honeycomb structure, the resonance frequency can be adjusted and the size of the cavity resonator 4 can be reduced, and at the same time, the air flow in the internal space of the cavity resonator 4 can be reduced. The temperature distribution in the internal space of the cavity resonator 4 can be controlled by generating a desired convection by the rectifying action.

[0030]

According to the first aspect of the present invention, the microwave generating means for generating a microwave and the microwave generated by the microwave generating means having at least a part capable of transmitting light are supplied to the internal space. A cavity resonator and a lamp bulb in which a light-emitting substance that discharges and emits light by microwaves is sealed inside, and a lamp bulb disposed in the interior space of the cavity resonator. Since it is arranged, the size of the cavity resonator can be reduced by shortening the wavelength of the microwave when propagating in the dielectric, and as a result, the mechanical strength of the cavity resonator can be increased by miniaturization. Further, there is an effect that the deformation of the cavity resonator can be prevented and the luminous efficiency can be improved.

According to a second aspect of the invention, in the first aspect of the invention, since the dielectric itself is held by at least a part of the dielectric in the internal space of the cavity resonator, a member for holding the dielectric is provided. It is not necessary to prepare separately, and there is an effect that the structure can be simplified and the cost can be reduced.

According to the invention of claim 3, in the invention of claim 1 or 2, since the thickness of the dielectric is made nonuniform, the electric field distribution in the internal space of the cavity resonator is controlled according to the thickness of the dielectric. Therefore, there is an effect that plasma can be generated in the glass bulb with high efficiency.

The invention of claim 4 is the invention of claim 1 or 2 or 3.
In the invention, since the dielectric body is composed of an assembly of polygonal cylindrical bodies, the light emitted from the glass bulb passes through the dielectric body and is emitted to the outside, so that the luminous efficiency can be improved. is there.

According to the invention of claim 5, in the invention of claim 4, since the polygonal cylindrical body is a hexagonal cylindrical body, it is possible to improve the mechanical strength while making the dielectric material lightweight. effective.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, at least part of the surface of the dielectric is white, so that the reflectance of light on the surface of the dielectric is increased to further improve the luminous efficiency. There is an effect that it can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main part of a first embodiment.

FIG. 2 is a block diagram of the above.

FIG. 3 is a cross-sectional view showing the main parts of the second embodiment.

FIG. 4 is a cross-sectional view showing the main parts of the third embodiment.

FIG. 5 is a cross-sectional view showing another configuration of the above.

FIG. 6 is a sectional view showing a main part of a fourth embodiment.

FIG. 7 is a cross-sectional view showing the main parts of the fifth embodiment.

FIG. 8 is a plan view of an essential part of the cavity resonator of the above.

FIG. 9 is a cross-sectional view showing the main parts of the sixth embodiment.

[Explanation of symbols]

4 cavity 4a Combined window 5 lamp bulbs 6 Dielectric

Continued front page    (72) Inventor Shin Ogawa             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company F term (reference) 5C039 PP02 PP04 PP08 PP09 PP16

Claims (6)

[Claims] 1. A microwave generating means for generating a microwave, a cavity resonator having at least a part capable of transmitting light and having a microwave generated by the microwave generating means supplied to an internal space, and a microwave. And a lamp bulb which is disposed in an internal space of the cavity resonator, in which a luminescent material which discharges and emits light by waves is enclosed, and a dielectric is disposed in a strong electric field portion in the internal space of the cavity resonator. Microwave electrodeless discharge lamp device. 2. The microwave electrodeless discharge lamp device according to claim 1, wherein the dielectric itself is held by at least a part of the dielectric in the internal space of the cavity resonator. 3. The microwave electrodeless discharge lamp device according to claim 1, wherein the dielectric has a nonuniform thickness. 4. The microwave electrodeless discharge lamp device according to claim 1, wherein the dielectric body is an assembly of polygonal cylindrical bodies. 5. The microwave electrodeless discharge lamp device according to claim 4, wherein the polygonal tubular body is a hexagonal tubular body. 6. The microwave electrodeless discharge lamp device according to claim 1, wherein at least a part of the surface of the dielectric is white.