JPS6245666B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a light source device that utilizes microwave discharge, and particularly to one that improves the starting of an electrodeless discharge lamp.

Recently, high-frequency discharge has been used as a light source device that uses discharge.
In particular, light source devices that use microwaves as high-frequency waves are attracting attention. In conventional light source devices with electrodes, the life of the lamp is determined by the wear and tear of the electrodes, but in light source devices using microwaves, the lamp can be made electrodeless, resulting in a longer lamp life. In addition, there is no heat loss due to the electrodes, and the difference in discharge impedance is small between the initial state and the stable state, so it is easy to inject power in the initial state. Another feature is that it takes less time to reach maximum output.

As such a microwave discharge light source device, those shown in FIGS. 1 and 2 can be considered. Fig. 1 is a sectional view of an electrodeless discharge lamp, and Fig. 2 is a sectional view showing the configuration of a microwave discharge light source device using the lamp shown in Fig. 1. In the figure, 1 is a spherical shape. It is an electrodeless discharge lamp that is filled with at least a predetermined amount of mercury and a starting aid gas such as argon. 2 is a lamp wall of this electrodeless lamp 1 formed of transparent quartz; 3 is a lamp support portion protruding from the lamp wall in a rod shape;
4 is the magnetron, 5 is the magnetron antenna,
6 is a waveguide, 7 is a microwave cavity formed into a substantially hemispherical shape, and includes a light transmitting member which is a mesh plate 7a that blocks microwaves and allows light to pass through, and a reflecting plate 7b.
It is composed of a light reflective member. Reference numeral 8 indicates a power feeding port formed in the reflection plate 7b that passes between the microwave cavity 7 and the waveguide 6, and 9 indicates a magnetron 4.
and a cooling fan for cooling the electrodeless discharge lamp 1; 10 is a blower pipe for guiding cooling air from the cooling fan 9 into the waveguide 6 via the magnetron 4;
Reference numeral 11 designates a ventilation port provided in the waveguide 6 for introducing cooling air in the air pipe 10 into the waveguide 6, and reference numeral 13 designates a box body that covers the magnetron 4, the waveguide 6, the cavity 7, and the like.

In the microwave discharge light source device configured in this manner, the microwaves generated by the magnetron 4 are radiated into the waveguide 6 through the magnetron antenna 5. This microwave propagates through the waveguide 6 and forms a microwave leakage electromagnetic field in the cavity 7 through the feed port 8 . After about 5 to 10 seconds due to this microwave leakage electromagnetic field, the starting-assisting noble gas sealed in the lamp 1 is discharged, the lamp wall 2 is heated, and the mercury that had been attached to the lamp wall 2 is also evaporated. At this time, if a metal halide is sealed in the discharge lamp 1, the metal halide also evaporates, and the discharge becomes a discharge mainly consisting of metal vapor discharge. At this time, depending on the type of encapsulated metal, light is emitted with an emission spectrum unique to each metal, and this is used as a light source. In order to effectively utilize the light from this lamp 1, the rear surface of the cavity 7 is covered with a reflector 7.
The front surface is made of a metal mesh plate 7a that does not transmit microwaves but transmits light, so that light is emitted only in the forward direction. On the other hand, since the magnetron 4 and the lamp 1 need to be cooled during operation, the magnetron 4 is cooled by a cooling fan 9, and this cooling air passes through the air pipe 10, the air outlet 11, the waveguide 6, and the power supply port 8 to the lamp 1. After cooling, mesh plate 7
It is exhausted from a.

However, in the microwave discharge light source device configured in this way, when the electrodeless discharge lamp 1 is in the lighting state, the microwave cavity 7 is arranged at a position where it becomes a resonator. However, the opening of the power feed port 8 is relatively small so that microwave impedance matching can be achieved.
Moreover, since its size is fixed, the electromagnetic field leaking from the power supply port 8 when the power is turned on is reduced, so the time until the lamp 1 starts discharging is long, about 5 to 10 seconds, which poses a practical problem. .

This invention has been made in view of the above-mentioned points, and in a microwave discharge photoelectric device having an electrodeless discharge lamp, the size of the opening of the power feeding port that communicates between the waveguide and the microwave cavity is changed. The object of the present invention is to improve starting performance by providing a sliding plate to make the opening of the power supply port larger during starting compared to when the lamp is lit.

An embodiment of this invention is shown below in Figures 3 and 4.
To explain based on the figure, in the figure, 8 is a feed port formed in the reflection plate 7b that passes between the microwave cavity 7 and the waveguide 6, and is an opening larger than the size that allows microwave impedance matching. There is. A slide plate 14 is inserted through the end of the waveguide 6 on the side of the microwave cavity 7, and is used to change the size of the opening of the power feed port 8 by sliding it. Reference numeral 16 denotes a presser which is disposed in a hole 15 formed at the end of the waveguide 6 on the side of the microwave cavity 7 and holds the slide plate 14 in position.
8, one end is attached to this spring, and the other end is attached to the slide plate 14.
It consists of a presser plate 17 that comes into contact with the spring 18 at all times.
A pressing force of is applied to the slide plate 14 via the presser plate 17.

In the microwave discharge light source device configured in this way, first, slide the slide plate 14 against the pressing force of the spring 18 so that the opening of the power supply port 8 becomes larger, and then turn on the power. Then,
The microwave emitted by the magnetron 4 is radiated into the waveguide 6 through the magnetron antenna 5, and this microwave propagates through the waveguide 6 and causes a microwave leakage electromagnetic field into the cavity 7 through the feed port 8. Form. At this time, since the size of the opening of the power feed port 8 is increased, a large microwave leakage electromagnetic field is formed in the cavity 7, and the starting-assisting rare gas sealed in the lamp 1 is released almost instantly. The lamp wall 2 is discharged and the lamp wall 2 is heated, and the mercury and metal halides that had been attached to the lamp wall 2 are also evaporated, and the discharge becomes a discharge mainly consisting of metal vapor discharge. At this time, depending on the type of encapsulated metal, light is emitted with an emission spectrum unique to each metal, so that this can be used as a light source in the same way as shown in FIGS. 1 and 2.

Next, immediately after the lamp is turned on, the slide plate 14 is slid in a direction to close the opening of the power supply port 8 by visually observing the light emitted from the lamp or by detecting the light by a well-known light detection means. By making the portion large enough to match the microwave impedance, a stable lamp lighting condition can be maintained. In this microwave discharge light source device, the slide plate 14 and the waveguide 6
If there is a gap between the waveguide 6 and the microwave cavity 7, there is a possibility that electric discharge will occur in that part and damage the device. Slide plate 14
Since there is no gap between the slide plate 14, the waveguide 6, and the microwave cavity 7, no discharge occurs in this portion.

In the above embodiment, the slide plate 14 is slid manually, but it is also possible to use a well-known light detection means such as a photoelectric element and a drive device such as hydraulic pressure to drive the slide plate 14 in accordance with the output of this light detection means. The slide plate 14 may be automatically slid by using a combination of a motor or a motor.

As described above, the present invention is for lighting an electrodeless discharge lamp disposed in a microwave cavity connected to a waveguide via a power supply port using microwaves from a microwave oscillator. Since a slide plate is provided to change the size of the opening of the power supply port, the size of the opening of the power supply port is increased during startup to increase the microwave electromagnetic field inside the microwave cavity, resulting in an electrodeless discharge lamp. This has the effect of significantly improving the starting performance of the lamp, and after starting and lighting the lamp, the size of the opening of the power supply port can be made smaller to ensure microwave impedance matching, resulting in stable lighting of the electrodeless discharge lamp. .

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an electrodeless discharge lamp, Fig. 2 is a sectional view showing an example of a microwave discharge light source device using this lamp, and Fig. 3 is a microwave discharge light source device which is an embodiment of the present invention. 4th cross-sectional view showing
The figure is a sectional view of the main part of FIG. 3. In the figure, 1 is an electrodeless discharge lamp, 4 is a magnetron, 6 is a waveguide, 7 is a microwave cavity, 8 is a power supply port, and 14 is a slide plate. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A microwave oscillator, a waveguide that guides the microwaves oscillated by the microwave oscillator, and a waveguide connected to the waveguide through a power supply port, with one surface being a light-transmitting member and at least a portion of the other surface being a light-reflecting member. A point light source with a discharge luminescent substance sealed inside the microwave cavity is disposed at a position where the microwave cavity becomes a resonator at least when it is in a lit state. A microwave discharge light source device comprising an approximated electrodeless discharge lamp, characterized in that the microwave discharge light source device is provided with a slide plate for changing the size of an opening of a power supply port.