JPS5923613B2 - High frequency discharge light source device - Google Patents

Description

[Detailed description of the invention] This invention excites an electrodeless discharge lamp with high frequency energy,
The present invention relates to a high-frequency discharge light source device that obtains illumination light.

Conventionally, as one of the devices for lighting an electrodeless discharge lamp using high frequency waves, especially microwaves, Japanese Patent Application Laid-Open No. 50-54172
There are some that are shown in the publication.

FIG. 1 shows the light source device. In Fig. 1, numeral 1 denotes an elongated electrodeless high-pressure vapor discharge lamp, and numeral 2 denotes a semi-cylindrical reflector plate installed in the longitudinal direction at the rear of the discharge lamp 1, which is used for microwave and radiation. It is made of a material that is opaque to light from the electric lamp 1.

Reference numeral 3 denotes a light transmitting member that covers the fitl opening of the reflector plate 2 and is made of a material such as a metal net that is opaque to microwaves and transparent to the emitted waves from the discharge lamp 1. The body 3 and the reflecting plate 2 form a microwave cavity 4.

Note that 5 is a microwave oscillator, 6 is a waveguide, and 7 is a microwave coupling hole.

However, in the light source device with the above configuration, since the microwave cavity 4 is a non-resonant cavity, the coupling hole 7 is connected to the cavity 4.
When the energy propagates inside the cavity 4 and reaches the opposite end of the cavity 4, the energy becomes almost zero, and the discharge lamp 1 continues to discharge and emit light due to the microwave energy absorbed at this time. The emitted light wave is reflected directly or by the reflection plate 2, passes through the light transmitting body 3, and is emitted to the outside of the cavity 4.

Therefore, in the above device, the shapes of the discharge lamp 1 and the cavity 4 must necessarily be elongated shapes extending in the direction of microwave propagation, and therefore, it is natural to design the shape of the lighting equipment. There are additional restrictions, the fields of use are limited, and there are disadvantages in that it is difficult to uniformly supply sufficiently high energy over the entire length of the discharge lamp.

This invention was made in order to eliminate the above-mentioned drawbacks. By providing a spherical electrodeless discharge lamp in the resonant cavity, there is no need to make the cavity shape elongated, and moreover, the discharge lamp can generate sufficiently high energy. The purpose of this device is to provide a high-frequency discharge light source device that uniformly supplies light.

The present invention will be explained below based on examples.

FIG. 2 is a cutaway side view showing one embodiment of the present invention.

In the figure, 1 is a spherical electrodeless light lamp with a phosphor film 8 coated on the inner wall surface and argon and mercury sealed inside, and 2 is a spherical electrodeless light lamp that surrounds this electrodeless light lamp and is used to transmit microwaves and A light reflecting plate 3 is opaque to the light emitted from the electrodeless light lamp 1 and has a paraboloid of revolution shape, and a light reflecting plate 3 covers the aperture surface of the reflecting plate 2 and is opaque to the microwave and reflects the electrodeless light. It is a light transmitting body made of a metal net that substantially allows the emitted waves from the lamp to pass through, and this transmitting body 3 and the reflecting plate 2 form a microwave resonant cavity 4.

In addition, 7 is a microwave coupling hole provided in the reflection plate 2;
9 is a microwave oscillator that supplies microwaves into the resonant cavity 4 through the coupling hole 7, and 9 is a cable that supplies power into the oscillator.

In the high-frequency discharge light source device configured in this way, the microwave energy excited by the oscillator 5 is supplied into the resonant cavity 4 through the coupling hole 7, and resonates while being repeatedly reflected on the resonant cavity wall surface. A microwave electromagnetic field is created within the cavity 4.

The fluorescent lamp 1 sustains the discharge by absorbing the energy of this microwave electromagnetic field.

Visible light is generated by irradiating the phosphor film attached to the inner wall of the fluorescent lamp with the ultraviolet rays generated by this discharge.

This visible light passes through the light transmitting body 3 either directly or after being reflected from the reflecting plate 2LK-, and is used as illumination light.

In other words, the fluorescent lamp 1 absorbs energy from the microwave electromagnetic field formed within the resonant cavity 4 while the microwave is repeatedly reflected, and continues to discharge.

Therefore, unlike the case of lighting inside the non-resonant cavity 4, the fluorescent lamp 1 is elongated and extended in the propagation direction of microwave energy.
There is no need to install .

Here, we will talk about the advantage of making the electrodeless discharge lamp 1 spherical. Since the emitted light from the discharge lamp 1 is radially uniform in all directions, when using the emitted light, it is necessary to There are fewer restrictions on design, making light distribution design easier.

Further, when discharge occurs in the discharge lamp 1, the gas pressure within the discharge lamp 1 increases significantly, but the gas pressure on the wall surface of the discharge lamp 1 becomes uniform, so that the discharge lamp 1 is difficult to break.

Furthermore, if the shapes of the discharge lamps 1 are not equal in three dimensions, there is a possibility that uneven light emission will occur due to microwave discharge, but such a possibility does not exist.

Furthermore, when the microwave cavity is a resonant cavity, changing the shape of the reflector causes a problem in that the resonant frequency of the resonant cavity deviates from the frequency of the microwave used.

By changing the shape of the resonant cavity in a similar manner, the resonant frequency can be easily matched to the frequency of the microwave used.

In this case, the shape of the electrodeless discharge lamp serving as the light emitting source is a spherical shape that easily approximates a point light source, so the light distribution as a lighting fixture does not change significantly.

In addition, it is desirable that the shape of the cavity resonator be rotationally symmetrical in order not to greatly change the light distribution.If the inner surface shape of the resonator has a focal point, the shape should be adjusted to the lamp installation position. It is desirable to focus.

In this embodiment, the cavity resonator 4 is made of a light-reflecting member except for the part made of a light transmitting material, but this part is particularly light-reflecting. It is not necessary, and any member that reflects microwaves is sufficient.

Therefore, a light-absorbing coating may be applied to part or all of the light-reflecting member according to the light distribution required for the irradiated surface.

Further, in the above embodiment, an example of the fluorescent lamp 1 was described as an electrodeless discharge lamp in which the phosphor emits light using ultraviolet rays generated by low-pressure mercury vapor discharge, but in this invention, an electrodeless high-pressure metal vapor discharge It is also possible to make electric lights emit light.

However, in an electrodeless discharge lamp, since the discharge lamp absorbs microwave energy from its wall surface and discharges it, unlike the case of a right-hand polar discharge, the discharge lamp is characterized in that the discharge is unevenly distributed near the wall.

For this reason, in electrodeless low-pressure mercury vapor discharge lamps, self-absorption of resonance lines, which was one of the factors that reduced the luminous efficiency of conventional right-handed fluorescent lamps that utilize extremely low-pressure mercury vapor discharge, is reduced. It is characterized by high luminous efficiency.

Therefore, using a low-pressure mercury vapor discharge lamp as an electrodeless discharge lamp has an advantage over a high-pressure metal vapor discharge lamp, in which self-absorption of resonance lines does not cause a large decrease in luminous efficiency.

As explained above, according to the present invention, the high-frequency cavity is a resonant cavity having a member on at least one surface that blocks high-frequency waves and allows light to pass through, and a spherical electrodeless discharge lamp is disposed within the resonant cavity. Therefore, high energy can be supplied to the discharge lamp, there are fewer restrictions on light distribution design, there is less uneven light emission, and the discharge lamp is less likely to break.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram showing a conventional electrodeless discharge lamp light source device, and FIG. 2 is a cutaway side view of a high frequency discharge light source device showing an embodiment of the present invention. In the figure, 1 is an electrodeless discharge lamp, 2 is a light reflecting plate, 3 is a light transmitting body, 4 is a microwave cavity, 5 is a high frequency oscillator, and 8 is a fluorescent film. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A high-frequency oscillator, a high-frequency cavity resonator that is brought into a resonant state by high-frequency waves excited by the high-frequency oscillator, and has a member on at least one surface that blocks high-frequency waves and allows light to pass through, and this cavity resonator A high-frequency discharge light source device consisting of a spherical electrodeless discharge lamp that is disposed inside and encapsulates an ionizable medium. 2. The high-frequency discharge light source device according to claim 1, wherein the inner surface of the cavity resonator has a rotationally symmetrical shape. 3. The high frequency discharge light source device according to claim 2, wherein the cavity resonator has an inner surface shape of a paraboloid.