JP2008288025A - Microwave discharge lamp device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a microwave discharge lamp into a point light source, and provide a miniaturized microwave discharge lamp device. <P>SOLUTION: The microwave discharge lamp device is provided with a metal chamber, a discharge lamp arranged inside the metal chamber, and a reflecting mirror arranged inside the metal chamber for reflecting light from the discharge lamp. The discharge lamp has a first conductive component and a second conductive component arranged inside a discharge vessel, of which, the first conductive component is electrically connected with a microwave supply source through a sealing part formed at the discharge vessel, and the second conductive component is to be an electrically opened microwave discharge lamp device to achieve the point light source. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a discharge lamp that is lit using microwaves.

In recent years, the demand for high-pressure discharge lamps is increasing not only for general lighting but also for headlights for automobiles and backlights for projectors in place of halogen lamps because of their high efficiency and high color rendering.
In particular, in a discharge lamp using a microwave, since it is possible to couple electromagnetic energy to a luminescent material in the light emitting space without having an electrode in the light emitting space, it is possible to realize an electrodeless discharge lamp.

The electrodeless lamp does not cause blackening of the inner wall of the arc tube due to the evaporation of the electrode, so it can greatly improve the lamp life, and the substance that could not be used because it reacts with electrode materials such as sulfur Therefore, a light source with high efficiency and high color rendering can be realized.
In the conventional microwave discharge lamp, the discharge lamp is disposed in the microwave resonant cavity, the microwave generated from the magnetron is transmitted using the waveguide, and the microwave energy is sent to the microwave resonant cavity using the coupling hole. The discharge lamp is turned on. (Patent Document 1)
In consideration of use as a headlight for automobiles or a backlight for projectors, a point light source (less than 2 mm) is desirable for the plasma arc of the lamp in order to increase the utilization efficiency of optical light. However, it is very difficult to make an electrodeless lamp using a microwave as a point light source.

The reason for this is that since the electrodeless lamp has no electrode inside the light emitting space, the size of the plasma arc is determined by the size of the light emitting space, but when the light emitting space is reduced, the reflected power increases because it is difficult to combine microwave energy, Since the microwave energy cannot be used for discharge, the efficiency is deteriorated, and it is very difficult to manufacture a lamp having a light emitting space of 2 mm or less.
Furthermore, a lamp device using a waveguide or a microwave resonant cavity is very large, but since its size is determined by the frequency of the microwave used, it is difficult to reduce the size.

  Therefore, the present invention has a technical problem to realize a very small plasma arc in a discharge lamp that is lit using microwaves, and to reduce the size of the apparatus without requiring a microwave resonant cavity.

In order to solve this problem, a microwave discharge lamp device of the present invention includes a metal chamber, a discharge lamp disposed inside the metal chamber, and a discharge lamp disposed inside the metal chamber. A microwave discharge lamp device having a reflecting mirror for reflecting the light, wherein the discharge lamp has a first conductive component and a second conductive component disposed in a discharge vessel, and the first conductive component is The microwave discharge lamp device is electrically connected to a microwave supply source through a sealing portion formed in the discharge vessel, and the second conductive component is electrically opened.
Further, a coaxial cable or a microstrip line may be used to electrically connect the first conductive component and the microwave supply source.
The distance between the first conductive component and the second conductive component may be 2 mm or less, and 150 mg / cc or more of mercury may be enclosed in the discharge vessel.

According to the present invention, the first conductive component and the second conductive component are arranged in the discharge vessel, and the microwave power is supplied from the first conductive component, so that there is no microwave resonant cavity. Microwave discharge can be performed between the first conductive component and the second conductive component.
In addition, since microwave discharge is performed between the first conductive component and the second conductive component, a very small plasma arc can be realized without reducing the light emission space.
In addition, when a discharge lamp enclosing 150 mg / cc or more of mercury is used, an emission spectrum preferable as a projector lamp can be obtained.

Hereinafter, embodiments of the microwave discharge lamp system of the present invention will be described in detail.
Note that the microwave in this specification refers to an electromagnetic wave having a frequency of 300 MHz to 300 GHz.

FIG. 1 is a schematic diagram showing the configuration of an example of a microwave discharge lamp apparatus according to the present invention.
The discharge lamp 1 has a quartz discharge vessel 2a and narrow tube portions 2b and 2c connected thereto, and the discharge vessel 2a having an internal volume of 0.05 cc is filled with 10 mg of mercury, argon and a small amount of halogen.

The first conductive component 3a and the second conductive component 3b are made of tungsten and are disposed in the discharge vessel 2a so as to face each other with a spacing of 1 mm. The metal foils 4a and 4b made of molybdenum and the lead wires 5a and 5b are arranged. Is connected.
The first conductive component 3a is connected to the center conductor 6a of the coaxial connector 6 through the metal foil 4a and the lead wire 5a, and is configured to be supplied with microwaves from the microwave oscillator.
The reflecting mirror 7 is arranged so that the focal position of the reflecting mirror 7 having a spheroidal surface substantially coincides with the centers of the first conductive component 3a and the second conductive component 3b, and is emitted from the discharge lamp 1. The reflected light is reflected by the reflecting mirror 7 and can be taken out from the opening 9 provided in the metal chamber 8 and used.

The internal dimensions of the metal chamber 8 are 40 mm in height and 40 mm in width and 60 mm in length, and do not leak microwaves to the outside, and are very small compared to conventional microwave resonant cavities.
The size of the opening 9 is 10 mm in diameter, and if this is the case, the microwaves do not leak out of the metal chamber, and the light from the discharge lamp 1 reflected by the reflecting mirror 7 is fully utilized. can do.
The reflecting film formed on the reflecting mirror 7 is made of a dielectric material, and the material of the reflecting mirror 7 is preferably a material having a small dielectric loss such as quartz.

A microwave having an electric power of 100 W and a frequency of 2.45 GHz oscillated from the microwave oscillator is transmitted using a coaxial cable and supplied to the coaxial connector 6. The supplied microwave is transmitted in the order of the inner conductor 6a of the coaxial connector 6, the lead wire 5a, the metal foil 4a, and the first conductive component 3a, and is radiated from the first conductive component 3a to the second conductive component 3b. Is done.
The microwave transmitted to the second conductive component is transmitted to the metal foil 4b and the lead wire 5b, but nothing is electrically connected to the lead wire 5b, so-called electrically open. The microwave energy is reflected, returns from the metal foil 4b to the second conductive component 3b, and is transmitted again to the first conductive component 3a.
In this way, when microwave energy passes between the first conductive component 3a and the second conductive component 3b, a discharge occurs between the first conductive component 3a and the second conductive component 3b. Argon plasma sealed in the container 2a is formed.

The formed plasma raises the temperature of the discharge vessel 2a, and the enclosed mercury evaporates and is excited by microwave energy to emit light.
Since mercury emission occurs between the first conductive component 3a and the second conductive component 3b, a very small plasma can be realized, and 200 mg / cc of mercury is enclosed in the discharge vessel 2. Therefore, since the pressure during lighting increases and the arc becomes thinner, it becomes possible to make a further point light source, and the optical utilization efficiency can be increased.

Further, since the red component of light emission increases due to an increase in pressure during lighting, an emission spectrum preferable as a projector lamp can be obtained.
2, the lead wire 15a connected to the first conductive component 13a of the discharge lamp 11 may be connected to the microstrip line 10 and supplied with microwaves.

Used as a light source for automobiles and projectors.

It is a figure which shows an example of the microwave discharge lamp apparatus which concerns on this invention. It is a figure which shows the other form of the microwave discharge lamp system which concerns on this invention.

Explanation of symbols

1,11 Discharge lamps 2a, 12a Discharge vessels 2b, 2c, 12b, 12c Narrow tube portions 3a, 13a First conductive parts 3b, 13b Second conductive parts 4a, 4b, 14a, 14b Metal foils 5a, 5b, 15a, 15b Lead wire 6 Coaxial connector 6a Inner conductors 7, 17 Reflective mirrors 8, 18 Metal chambers 9, 19 Opening 10 Microstrip line

Claims (6)

A microwave discharge lamp device having a metal chamber, a discharge lamp disposed inside the metal chamber, and a reflecting mirror disposed inside the metal chamber and reflecting light from the discharge lamp;
The discharge lamp has a first conductive component and a second conductive component arranged in a discharge vessel,
The microwave discharge lamp device, wherein the first conductive component is electrically connected to a microwave supply source via a sealing portion formed in the discharge vessel. The microwave discharge lamp device according to claim 1, wherein the second conductive component is electrically opened. The microwave discharge lamp device according to claim 1 or 2, wherein the first conductive component and the microwave supply source are connected by a coaxial cable. The microwave discharge lamp device according to claim 1 or 2, wherein the first conductive component and the microwave supply source are connected by a microstrip line. The microwave discharge lamp device according to any one of claims 1 to 4, wherein a distance between the first conductive component and the second conductive component in the discharge vessel is 2 mm or less. The microwave discharge lamp device according to any one of claims 1 to 5, wherein mercury of 150 mg / cc or more is sealed in the discharge lamp.

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