JPH09320543A - Microwave electrodeless discharge light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microwave electrodeless discharge light source device which causes a discharge using microwaves, is compact, and has high efficiency and long life. SOLUTION: All the component surfaces of a microwave cavity 5 and the component surface of a waveguide 3 are made of conductive members that reflect microwaves but are pervious to light and fluids, and light reflectors 11, 111 are placed outside the component surfaces to constitute a microwave electrodeless discharge light source device. Therefore, cooling efficiency is enhanced, a device is made lightweight, and light emitted in a direction in which it cannot be utilized with conventional constitution is utilized to enhance the rate of utilizing the light.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electrodeless discharge light source device that discharges with microwaves.

[0002]

2. Description of the Related Art In recent years, a light source device, which is excellent in environmental protection and energy saving and which obtains a light output by discharge using microwaves, has been attracting attention. The life of a discharge lamp having an electrode such as a metal halide lamp or a mercury lamp is fixed due to the consumption of the electrode. However, since the microwave electrodeless discharge lamp has no electrode, it is essentially a long-life light source. Further, since there is no electrode, there is little change in the emission spectrum over time, and a discharge lamp that is substantially smaller than an electrodeed discharge lamp can be made. Therefore, there is a possibility that a light source close to a point light source, which is ideal for controlling the projected light, can be obtained. Furthermore, this lamp is strong in blinking operation and has excellent starting / restarting characteristics as compared with an electrode lamp.

FIG. 4 is a sectional view showing the structure of a microwave electrodeless discharge light source device disclosed in, for example, Japanese Patent Laid-Open No. 63-237302. FIG. 4 shows a magnetron 1 that oscillates microwaves having a frequency of 2450 MHz, a magnetron antenna 2, and a waveguide 3 in which the magnetron 1 is arranged at an end. The microwave cavity 5 is formed by being surrounded by a cavity wall 6 connected to the other end of the waveguide 3 and a light-transmissive cylindrical metal mesh member 7. The power supply port 8 is provided in the cavity wall 6 and supplies microwaves from the waveguide 3 into the microwave cavity 5. A spherical electrodeless discharge lamp 9 is arranged in the microwave cavity 5. The electrodeless discharge lamp 9 is a transparent body such as quartz glass in which a rare gas, mercury, and a metal halide are enclosed.
The discharge lamp support 91 is a dielectric material such as quartz glass attached to the outer wall of the electrodeless discharge lamp 9, and has a power supply port 8
It also penetrates the wall surface of the waveguide 3 and is fixed to the rotation shaft of the electrodeless discharge lamp rotation motor 14 outside the waveguide 3. The light reflector 11 reflects the light emitted from the microwave cavity 5, the cooling fan 12 cools the magnetron 1 and the electrodeless discharge lamp 9, and the ventilation port 4 guides the cooling air into the waveguide. The box 13 covers the whole of the light reflector 11 except for the opening 100 which is a light exit.

The operation of this conventional device will be described. First, the microwave generated from the magnetron 1 is radiated from the magnetron antenna 2 to the waveguide 3. The microwave conducted in the waveguide 3 is radiated from the power feed port 8 to the microwave cavity 5. The microwave entering the microwave cavity 5 forms a high-frequency electromagnetic field in the microwave cavity 5. This high-frequency electromagnetic field causes the gas in the electrodeless discharge lamp 9 installed in the microwave cavity 5 to start discharging, and a desired optical output can be obtained in a few seconds.

The cylindrical metal mesh member 7 acts so as to reflect microwaves and transmit light through the mesh openings. Therefore, the high-frequency electromagnetic field is concentrated in the microwave cavity 5, causing the electrodeless discharge lamp 9 disposed therein to emit light. The light thus emitted is radiated from the cylindrical metal mesh member 7 to the outside of the cavity and is reflected by the light reflector 11 in a specific direction. The shape of the light reflector 11 is determined by the application such as the required light irradiation distribution. As the shape of the electrodeless discharge lamp 9, a sphere, a shape close to a sphere, or an elongated cylindrical shape is often used as shown in FIG. To facilitate starting, the gas pressure in the electrodeless discharge lamp 9 is set to 200 Torr or less at the time of starting. The enclosed material becomes vapor and the pressure rises, and at the time of steady lighting, it reaches a gas pressure (about several atmospheric pressure) for generating sufficient plasma to obtain efficient light emission. The total pressure inside the electrodeless discharge lamp 9 is mainly due to a filling material other than mercury or a rare gas, and a peculiar plasma discharge light emission can be obtained by the filling material.

Magnetron 1 and electrodeless discharge lamp 9
Have high temperatures during operation and therefore require cooling. Therefore, the cooling air from the cooling fan 12 first cools the magnetron 1, then is guided into the waveguide 3 through the ventilation port 4 provided in the waveguide 3, and further through the power supply port 8. Is guided into the microwave cavity 5 to cool the electrodeless discharge lamp 9. The cooling air is discharged to the outside of the device through the cylindrical metal mesh member 7.

Further, depending on the direction of the electromagnetic field formed by the microwave in the microwave cavity 5, the plasma discharge portion formed in the electrodeless discharge lamp 9 may have a flat shape, or may not be formed. The gas in the electrode discharge lamp 9 is convected and the temperature of the upper part of the electrodeless lamp 9 becomes high. Therefore, the temperature distribution of the tube wall of the electrodeless discharge lamp 9 becomes uneven, and therefore the electrodeless discharge is locally generated. The softening point of the quartz glass forming the lamp 9 may be reached. In such a case, damage due to melting of the tube wall and devitrification of the tube wall material are likely to occur, and the life of the light source is shortened. In order to prevent the mode of the electromagnetic field formed in the electrodeless discharge lamp 9 from being fixed in this way, the electrodeless discharge lamp 9 is rotated by the motor 14, and thus the temperature of the wall of the electrodeless discharge lamp 9 is reduced. It is made uniform with respect to the rotation axis to prevent the temperature of the tube wall from rising locally. At the same time, the rotation also equalizes the cooling effect by the cooling air blown to the electrodeless discharge tube 9.

A liquid crystal projection type image display device utilizing the advantages that the microwave electrodeless discharge light source has higher brightness and longer life than the conventional electroded discharge lamp and has the potential as a small arc tube. Has also been attempted to be used as a backlight light source for light sources (for example, "Small and long-life stable light source for projection display" by DA McLennan, SID
International Symposium / Technical Digest 24, 7
16-719 ("Small Long-Lived Stable Light Sou
rce for Projection-Display Applications "DAMacLe
nnan, SID InternationalSynposium Digest of Technica
l PapersVolumeXXIV, pp, 716-719).

[0009]

In the electrodeless discharge, the plasma generated inside the electrodeless discharge lamp 9 at the time of lighting spreads to the vicinity of the tube wall, so that the tube wall temperature rises. Further, since the components of the microwave electrodeless discharge light source device such as the microwave cavity and the waveguide have a relatively large volume and are heavy, it is desirable to make them as small as possible. However, as the size gets smaller, the temperature of these components tends to rise,
Therefore, the electrodeless discharge lamp 9 and the magnetron 1 are indirectly heated, which causes a temperature rise. Such a temperature rise is a factor relating to the life of the microwave electrodeless discharge light source device. Therefore, a cooling efficiency higher than that of the conventional cooling means shown in FIG. 4 has been demanded.

Further, the microwave electrodeless discharge light source device is
Since the electrodeless discharge lamp 9 is disposed inside the microwave cavity 5, some of the light generated from the electrodeless lamp 9 is absorbed or absorbed by the cylindrical metal mesh member 7 forming the microwave cavity 5. It is reflected inside the cavity and is not extracted outside the cavity. Further, most of the light emitted toward the power feed port 8 side of the microwave cavity 5 is the power feed port 8
It is not used because it travels to the inside of the waveguide 3 by taking it. Therefore, the utilization factor of light actually generated is considerably lower than that of the electroded discharge lamp. The present invention has been made to solve the above problems, and an object of the present invention is to provide a microwave electrodeless discharge light source device having a higher efficiency and a longer life, which has better cooling efficiency than conventional ones and higher light utilization efficiency. There is.

[0011]

A microwave electrodeless discharge light source device according to the present invention is capable of reflecting microwaves but transmitting light and fluid through the entire wall surface of a microwave cavity and the wall surface of a waveguide. And a member having electrical conductivity, and a light reflector is arranged outside of the wall surfaces of those members. According to the present invention, the flow of fluid that contributes to cooling can be improved, and cooling efficiency can be improved. Further, the light emitted toward the cavity wall 6, which cannot be used in the conventional configuration, can be used, and the light utilization rate is improved.

[0012]

A microwave electrodeless discharge light source device according to a first aspect of the present invention is a microwave electrodeless discharge light source device which discharges and emits light by a microwave electromagnetic field in a microwave cavity. A microwave generation source and a microwave cavity in which all wall surfaces are made of a conductive material that reflects microwaves but transmits light and fluid,
A waveguide for guiding microwaves from the microwave generation source to the microwave cavity, an electrodeless discharge lamp arranged in the microwave cavity, and light generated from the electrodeless discharge lamp in a specific direction. And a light reflector for projecting. As a result, the cooling air has the effect of uniformly cooling the electrodeless discharge lamp.

A microwave electrodeless discharge light source device according to a second aspect of the present invention is the microwave electrodeless discharge light source device according to the first aspect, wherein at least a part of the wall surface of the waveguide reflects microwaves. Is composed of a member that transmits light and fluid and has conductivity. As a result, the waveguide has a small heat capacity and a large surface area, and the cooling air has the effect of efficiently cooling the waveguide.

A microwave electrodeless discharge light source device according to a third aspect of the present invention is the one according to the first aspect or the second aspect, wherein the microwave forming the microwave cavity is reflected. However, the member that transmits light and fluid and has conductivity is a metal mesh. As a result, the cooling air has the effect of uniformly cooling the electrodeless discharge lamp.

A microwave electrodeless discharge light source device according to a fourth aspect of the present invention is the microwave electrodeless discharge light source device according to the second or third aspect, wherein at least a part of the wall surface of the waveguide is formed. The metal mesh is used as the member that reflects microwaves but transmits light and fluid and has conductivity. As a result, the heat capacity of the waveguide is reduced, and the cooling air has the effect of efficiently cooling the waveguide.

A microwave electrodeless discharge light source device according to a fifth aspect of the present invention is the microwave electrodeless discharge light source device according to the second aspect, the third aspect or the fourth aspect, wherein the light reflector is the microwave. A first mounting member having a reflection surface shape which is mounted on the outside of the cavity and reflects light emitted from the electrodeless discharge lamp and transmitted through the microwave cavity to project in a specific direction;
Mounted on the outside of the waveguide and the light reflector of, and the microwave emitted from the electrodeless discharge lamp reflects the microwave of the microwave cavity and the waveguide but transmits light and fluid and is conductive. It is characterized by having two light reflectors, that is, a second light reflector that reflects the light transmitted through the member having the above and projects it in a specific direction. Thus, the light emitted from the electrodeless discharge lamp and emitted in the direction of the wall surface of the waveguide is reflected in the light irradiation direction of the microwave electrodeless discharge device.

Embodiments of the present invention will be described below with reference to the drawings. << Embodiment 1 >> FIG. 1 shows a sectional view of a microwave electrodeless discharge light source device according to a first embodiment of the present invention. The magnetron 1 is a microwave generation source and generates a microwave of 2450 MHz, and the magnetron antenna 2 radiates the generated microwave to the waveguide 3. The magnetron 1 is arranged at one end of the waveguide 3. At the other end of the waveguide 3, there is provided a partition wall surface 31 for partitioning the microwave cavity and the waveguide. Further, a power supply port 8 is provided on the partition wall surface 31, and microwaves are supplied from the waveguide 3 to the microwave cavity 5 via the power supply port 8. A spherical electrodeless discharge lamp 9 is arranged in the microwave cavity 5. The electrodeless discharge lamp 9 is obtained by enclosing a rare gas, mercury, a metal halide, etc. in a transparent body such as quartz glass.

The microwave radiated in the microwave cavity 5 forms a high frequency electromagnetic field in the microwave cavity 5. The high-frequency electromagnetic field causes the gas in the electrodeless discharge lamp 9 installed in the microwave cavity 5 to start discharging, and obtains a desired optical output in a few seconds.

A discharge lamp support 91 made of a dielectric material such as quartz glass is attached to the outer wall of the electrodeless discharge lamp 9. The discharge lamp support 91 penetrates the power supply port 8 and thus the partition wall surface 31, and is fixed to the rotation shaft of the electrodeless discharge lamp rotation motor 14 outside the waveguide 3. The light reflector 11 reflects the light emitted from the microwave cavity 5 and irradiates this light in the light irradiation direction of the microwave electrodeless discharge light source device. The box 13 covers the entire microwave electrodeless discharge light source device according to the present invention, except for the opening 100 which is the light exit of the light reflector 11.

The partition wall surface 31 and the cylindrical metal mesh member 7 constitute the microwave cavity 5. In the waveguide 3 made of a metal material, including the partition wall surface 31,
Holes having a diameter of several mm are densely provided over the entire surface of all the constituent wall surfaces.

The cooling air from the cooling fan 12 cools the magnetron 1 and the waveguide 3. Since holes are formed in the entire wall surface of the waveguide 3, the waveguide 3
Has a small heat capacity and a large surface area, and cooling air can enter and exit from anywhere. Therefore, the waveguide 3 is efficiently cooled. Further, the cooling air cools the electrodeless discharge lamp 9 arranged inside the microwave cavity 5 through the holes formed in the partition wall surface 31 and the power supply port 8. At this time, a large amount of cooling air flows into the microwave cavity 5 through the holes formed in the partition wall surface 31 in large numbers. Therefore, as compared with the conventional configuration in which only the power supply port 8 is a ventilation port, the electrodeless discharge lamp 9 is generally cooled and evenly cooled. The cooling air further passes through the cylindrical metal mesh member 7 to the outside of the microwave cavity 5, and the light reflector 1
1 also flows out of the device while cooling. Since the holes are formed in the entire waveguide 3, there is also an advantage that the weight of the waveguide 3 is significantly reduced.

<Embodiment 2> FIG. 2 shows a sectional view of a microwave electrodeless discharge light source device according to a second embodiment of the present invention. The magnetron 1 is a microwave source
The microwave of 50 MHz is generated, and the magnetron antenna 2 radiates the generated microwave to the waveguide 3. The magnetron 1 is arranged at one end of the waveguide 3. At the other end of the waveguide 3, there is provided a partition wall surface 31 for partitioning the microwave cavity and the waveguide. Further, a power supply port 8 is provided on the partition wall surface 31, and microwaves are supplied from the waveguide 3 to the microwave cavity 5 via the power supply port 8. A spherical electrodeless discharge lamp 9 is arranged in the microwave cavity 5. The electrodeless discharge lamp 9 is obtained by enclosing a rare gas, mercury, a metal halide, etc. in a transparent body such as quartz glass.

The microwave radiated in the microwave cavity 5 forms a high frequency electromagnetic field in the microwave cavity 5. The high-frequency electromagnetic field causes the gas in the electrodeless discharge lamp 9 installed in the microwave cavity 5 to start discharging, and obtains a desired optical output in a few seconds.

A discharge lamp support 91 made of a dielectric material such as quartz glass is attached to the outer wall of the electrodeless discharge lamp 9. The discharge lamp support 91 penetrates the power supply port 8 and thus the partition wall surface 31, and is fixed to the rotation shaft of the electrodeless discharge lamp rotation motor 14 outside the waveguide 3. The light reflector 11 reflects the light emitted from the microwave cavity 5 and irradiates this light in the light irradiation direction of the microwave electrodeless discharge light source device. The box 13 covers the entire microwave electrodeless discharge light source device according to the present invention, except for the opening 100 which is the light exit of the light reflector 11.

The partition wall surface 31 and the cylindrical metal mesh member 7 constitute the microwave cavity 5. In the waveguide 3 made of a metal material, including the partition wall surface 31,
Holes having a diameter of several mm are densely provided over the entire surface of all the constituent wall surfaces.

The cooling air from the cooling fan 12 cools the magnetron 1 and the waveguide 3. Since holes are formed in the entire wall surface of the waveguide 3, the waveguide 3
Has a small heat capacity and a large surface area, and cooling air can enter and exit from anywhere. Therefore, the waveguide 3 is efficiently cooled. Further, the cooling air cools the electrodeless discharge lamp 9 arranged inside the microwave cavity 5 through the holes formed in the partition wall surface 31 and the power supply port 8. At this time, a large amount of cooling air flows into the microwave cavity 5 through the holes formed in the partition wall surface 31 in large numbers. Therefore, as compared with the conventional configuration in which only the power supply port 8 is a ventilation port, the electrodeless discharge lamp 9 is generally cooled and evenly cooled. The cooling air further passes through the cylindrical metal mesh member 7 to the outside of the microwave cavity 5, and the light reflector 1
1 also flows out of the device while cooling. Since the holes are formed in the entire waveguide 3, there is also an advantage that the weight of the waveguide 3 is significantly reduced.

In this embodiment, the partition wall facing waveguide-constituting wall surface 32 is replaced with the partition wall surface 31 in which the power supply port 8 is formed.
It is provided at a position facing. The discharge lamp support 91 penetrates this. This partition wall facing waveguide structure wall surface 3
A second light reflector 111 is provided outside the first light reflector 11 on the outer side of the second light reflector 2. By doing so, the electrodeless discharge lamp 9 radiates in the direction of the partition wall surface 31 and passes through the waveguide 3 to form the partition wall facing waveguide forming wall surface 3
The light that has passed through 2 is reflected in the light irradiation direction of the light source device by the second light reflector 111, so that the light wasted conventionally can be effectively used. In order to make the irradiation distribution of the light reflected and irradiated by the second light reflector 111 uniform, the second light reflector 111 is connected to the electrodeless discharge lamp rotation motor 14
Alternatively, it can be attached to the electrodeless discharge lamp support 91 and rotated.

<< Third Embodiment >> FIG. 3 shows a sectional view of a microwave electrodeless discharge light source device according to a third embodiment of the present invention. In the present embodiment, the metal mesh members 33 and 3
4 is the partition wall surface 31 shown in FIG. 1 or FIG. 2, respectively.
Also, the partition wall face is provided so as to face the position of the waveguide constituting wall face 32. Then, the discharge lamp support 91 penetrates the connecting portion between the waveguide end wall 35 and the cylindrical metal mesh member 7 from the outside of the waveguide end wall 35 on the power feed port 8 side.
On the outer side of the metal mesh member 34, a second light reflector 111 is provided in addition to the first light reflector 11 described above. Note that the other configurations are the same as those in the above-described embodiments. With such a configuration, the electrodeless discharge lamp 9 is connected to the metal mesh 33.
The light radiated in the direction of and transmitted through the metal mesh 34 through the waveguide is reflected in the light irradiation direction of the light source device by the second light reflector 111, so that the light wasted conventionally is effectively used. be able to. Moreover, the metal mesh members 33, 3
Since light is transmitted through No. 4, the light utilization efficiency is further improved as compared with the case where light is transmitted through the partition wall surface 31 and the partition wall facing waveguide-constituting wall surface 32 having the holes in the second embodiment.

FIG. 1 used to describe the first and second embodiments.
2 and 2, metal mesh members 33 and 34 may be used for either or both of the partition wall surface 31 and the partition wall facing waveguide-constituting wall surface 32, and FIG. 3 used in the description of the third embodiment. Metal mesh member 33 of
Either or both of 34 may be configured by the partition wall surface 31 or the partition wall surface facing waveguide forming wall surface 32 in which holes are densely formed.

[0030]

In the microwave electrodeless discharge light source device of the present invention, power is supplied by forming all the walls of the microwave cavity with a member that reflects microwaves but transmits light and objects and has conductivity. Compared with the case where only the mouth is provided and the ventilation hole is provided, the cooling air cools the electrodeless discharge lamp evenly, so that there is an effect that it is possible to realize a microwave electrodeless discharge light source device having a longer life than before.

Further, since at least a part of the wall surface of the waveguide is made of a member that reflects microwaves but transmits light and objects and has conductivity, the waveguide has a small heat capacity and a large surface area. Therefore, the cooling air has an effect of efficiently cooling the waveguide.

Further, by using a metal mesh as the member forming the microwave cavity, which reflects microwaves but transmits light and fluid and has conductivity, it is more effective than the case where the partition wall surface is used. In addition, the cooling air has the effect of uniformly cooling the non-polar discharge lamp.

Further, a member which constitutes at least a part of the wall surface of the waveguide and which reflects microwaves but transmits light and fluid and has conductivity is made of a metal mesh member to partition this part. Since the heat capacity of the waveguide is smaller than that in the case where the wall surface or the partition wall face the waveguide constituting wall surface, the cooling air has an effect of efficiently cooling the waveguide.

Further, by using the first and second light reflectors, it is possible to effectively use the light which was conventionally wasted.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of a microwave electrodeless discharge light source device according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a configuration of a microwave electrodeless discharge light source device according to a second embodiment of the invention.

FIG. 3 is a sectional view showing a configuration of a microwave electrodeless discharge light source device according to a third embodiment of the invention.

FIG. 4 is a sectional view showing a configuration of a conventional microwave electrodeless discharge light source device.

[Explanation of symbols]

 1 Magnetron 2 Magnetron Antenna 3 Waveguide 4 Vent 5 Microwave Cavity 6 Cavity Wall 7 Cylindrical Metal Mesh Member 8 Feed Port 9 Electrode Discharge Lamp 11,111 Light Reflector 12 Cooling Fan 13 Box 14 Electrode Discharge Lamp Rotation motor 31 Partition wall surface 32 Partition wall surface Opposing waveguide constituent wall surface 33, 34 Metal mesh member 35 Waveguide end wall 91 Discharge lamp support 100 Light exit

Claims (5)

[Claims] 1. A microwave electrodeless discharge light source device which discharges and emits light by a microwave electromagnetic field in a microwave cavity, wherein the microwave source and the microwave are reflected, but light and fluid are transmitted and have conductivity. A microwave cavity in which all wall surfaces are made of a member, a waveguide for guiding microwaves from the microwave generation source to the microwave cavity, and an electrodeless discharge lamp arranged in the microwave cavity,
A microwave electrodeless discharge light source device, comprising: a light reflector for projecting light generated from the electrodeless discharge lamp in a specific direction. 2. The wall surface of at least a part of the waveguide,
The microwave electrodeless discharge light source device according to claim 1, wherein the microwave electrodeless discharge light source device is configured by a member that reflects microwaves but transmits light and fluid and has conductivity. 3. The metal mesh is used as a member that constitutes the microwave cavity and that reflects microwaves but transmits light and fluid and has conductivity.
Alternatively, the microwave electrodeless discharge light source device according to claim 2. 4. A metal mesh is used as a member which constitutes at least a part of the wall surface of the waveguide and which reflects microwaves but transmits light and fluid and has conductivity. 2. The microwave electrodeless discharge light source device according to claim 2 or claim 3. 5. The reflection, wherein the light reflector is mounted outside the microwave cavity and reflects the light emitted from the electrodeless discharge lamp and transmitted through the microwave cavity to project the light in a specific direction. A first light reflector having a surface shape, and is mounted on the outside of the waveguide, is emitted by the electrodeless discharge lamp, and reflects the microwave of the microwave cavity and the waveguide, but is a light or fluid. Secondly projects light in a specific direction by reflecting light transmitted through a member having electrical conductivity.
2. The microwave electrodeless discharge light source device according to claim 2, 3 or 4, further comprising: