JP2623504B2 - Microwave-excited electrodeless light-emitting device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave-excited electrodeless light-emitting device that emits light by exciting with a microwave an electrodeless arc tube filled with a light-emitting material such as mercury.

[Conventional technology]

For example, as disclosed in JP-A-50-54172, an arc tube in which a light-emitting material such as mercury is conventionally sealed is used.
2. Description of the Related Art A microwave-excited electrodeless light-emitting device that emits light when excited by microwaves is known. This light-emitting device is usually used as an ultraviolet light source, and its application to curing of an ultraviolet-curable resin, photolithography in the production of a semiconductor device, treatment for improving the heat resistance of a resist, and the like has been attempted.

The advantage of the microwave-excited electrodeless light-emitting device is that it is not necessary to dispose electrodes inside the arc tube, so that the diameter of the arc tube can be reduced, and therefore it is closer to a linear light source than a light-emitting device with electrodes. In other words, the accuracy when combined with an optical system such as a trough-shaped parabolic mirror can be improved. In addition, the fact that the diameter of the arc tube is small also means that the heat radiation of the tube wall itself is reduced, and this is preferable when the object to be irradiated with light has low heat resistance.

FIGS. 3 and 4 are schematic illustrations of such a conventional microwave-excited electrodeless light emitting device, of which FIG. 3 is a cross-sectional view in the longitudinal direction, and FIG. It is sectional drawing in an arbitrary direction. 1 is an electrodeless arc tube, 2 is a microwave cavity, 3 is a microwave cavity wall, 4 is a slot as coupling means, 5 is a waveguide, 6 is a magnetron as microwave generating means, and 8 is a microwave seal Shows the mesh of.

3 and 4, the temperature of the electrodeless arc tube 1 rises due to the coupling of the microwave introduced through the slot 4, and the light-emitting material such as mercury sealed therein evaporates to a plasma state. It is excited and emits light. The tube wall of the electrodeless arc tube 1 is usually made of a high melting point glass such as quartz glass, but devitrifies when the temperature reaches, for example, about 900 to 1000 ° C. or more due to microwave coupling. Therefore, as shown in FIG. 3 and FIG.
A cooling hole 31 is provided in the cooling device so that the air from the blower blower 10 for cooling the entire device reaches the electrodeless arc tube 1 for cooling.

As disclosed in Japanese Patent Publication No. 55-35825, the longitudinal surface of the microwave cavity wall 3 has, for example, a parabolic cross section and is formed as an optical reflecting surface. Therefore, the microwave cavity wall 3 also functions as a light collecting mirror for the light from the electrodeless arc tube 1.

[Technical problem to be solved by the invention]

As described above, the advantage of the microwave-excited electrodeless light-emitting device is that the diameter of the electrodeless light-emitting tube 1 can be reduced. That is, making the diameter of the electrodeless arc tube 1 smaller means that the surface area of the electrodeless arc tube 1 becomes smaller.
The heat load on the tube wall increases. On the other hand, the electrodeless arc tube 1 is usually arranged at the focal point on the longitudinal surface of the microwave cavity wall 3 functioning as a condenser mirror.
When the diameter is smaller, the distance d between the ventilation hole 9 for cooling and the electrodeless arc tube 1 shown in FIG. 4 becomes longer, and the wind velocity of the cooling air must be reduced. In this case, for example, when the electrodeless arc tube 1 becomes thinner with an outer diameter of 8 mm and an inner diameter of 6 mm and the wind speed of the cooling air decreases, the predetermined cooling necessary for preventing the above-described devitrification cannot be performed, and the cooling air The amount of air flowing along the tube wall surface of the bottom portion 11 of the electrodeless arc tube 1 on the back side with respect to the direction of entry of the light is reduced, so that the cooling balance is deteriorated.

[Object of the invention]

The present invention has been made in view of such a problem, and even if the diameter of the electrodeless arc tube is reduced, the required predetermined cooling of the electrodeless arc tube is possible, and the microwave-excited type has a good cooling balance. It is intended to provide an electrode light emitting device.

〔Constitution〕

In order to achieve this object, the microwave-excited electrodeless light-emitting device of the present invention comprises a rod-shaped electrodeless light-emitting tube in which a light-emitting material is sealed, and a microwave cavity in which the electroless light-emitting tube is arranged. A microwave cavity wall, microwave coupling means for coupling microwaves to the microwave cavity, a microwave waveguide, and microwave generation means, and are arranged so as to surround the rod-shaped electrodeless arc tube. And a ventilation means for sending air into the ventilation pipe.

[Action]

In the microwave-excited electrodeless light-emitting device of the present invention having the above-described configuration, predetermined cooling of the electrodeless light-emitting tube is achieved by wind flowing in the ventilation pipe in the longitudinal direction of the electrodeless light-emitting tube, and the cooling balance is good.

〔Example〕

 Hereinafter, embodiments of the present invention will be described.

1 and 2 are schematic explanatory views of a microwave-excited electrodeless light-emitting device according to an embodiment of the present invention, wherein FIG. 1 is a cross-sectional view in the longitudinal direction, and FIG. It is sectional drawing in a perpendicular direction. Reference numeral 12 denotes a ventilation pipe, 13 denotes a blower as a blowing means, and 77 denotes a gutter-shaped mirror formed of a cold mirror. In addition, the same reference numerals as those in FIGS. 3 and 4 indicate the same or corresponding parts.

In FIGS. 1 and 2, the ventilation pipe 12 is made of quartz glass having a good ultraviolet transmittance, and has a cylindrical shape with an inner diameter of about 15 to 30 mm. The cylindrical ventilation pipe 12 is disposed so as to surround the electrodeless arc tube 1 at the center.

The blower 13 as a blowing means is provided to face one side opening 121 of the ventilation pipe 12. The air sent by the blower 13 flows in the ventilation pipe 12 in the longitudinal direction, uniformly cools the wall of the electrodeless arc tube 1 in a well-balanced manner, and then flows out of the apparatus from the other side opening 122 of the ventilation pipe 12. Is discharged. The wind speed of the wind flowing through the ventilation pipe 12 may be about 20 to 30 m / s. The blower 13 as the blowing means is a ventilation pipe 12
Blows the air through the side opening 122 of the ventilation pipe 12.
It is technically equivalent to provide an exhaust fan on the side.

In this embodiment, the gutter-shaped mirror 77 is configured as a code mirror that transmits part of infrared light and visible light and reflects ultraviolet light and other visible light. Since the temperature of the cold mirror 77 also rises due to light emission from the electrodeless arc tube 1 and radiant heat from the tube wall itself, cooling is required. For this reason, in this embodiment,
The wind from the blower blower 10 flows from the hole 31 of the microwave cavity wall 3 to the back surface 772 of the cold mirror 77 and the hole 771 provided in the cold mirror 77 along the surface 773 of the cold mirror 77 and the outer surface 123 of the ventilation pipe 12. Flow, cold mirror 77
And the ventilation pipe 12 is cooled. In this case, an exhaust blower may be used instead of the blower blower 10.

Although the ventilation pipe 12 of the present embodiment has a uniform inner diameter, in order to control the wind pressure and improve the cooling balance,
A taper, a step or the like may be provided so that the inner diameter changes between the inflow side and the outflow side of the wind.

[Effects of the Invention] As described above, the microwave-excited electrodeless light-emitting device of the present invention has a light-transmitting ventilation pipe arranged around a rod-shaped electrodeless light-emitting tube, and a wind inside the external ventilation pipe. Since the air blower is provided, the wall of the electrodeless arc tube is uniformly and well-cooled by wind flowing in the longitudinal direction of the electrodeless arc tube in the ventilation pipe. Therefore, even if the diameter of the electrodeless arc tube is reduced, the necessary predetermined cooling can be performed by appropriately designing the air velocity and the air volume of the air blowing means,
There is no problem such as devitrification of the electrodeless arc tube.

[Brief description of the drawings]

FIGS. 1 and 2 are schematic explanatory views of a microwave-excited electrodeless light emitting device according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view in a longitudinal direction, FIG. 2 is a cross-sectional view in a direction perpendicular to the longitudinal direction, and FIGS. 3 and 4 are schematic explanatory diagrams of a conventional microwave-excited electrodeless light emitting device. FIG. 3 is a cross-sectional view in a longitudinal direction, and FIG. 4 is a cross-sectional view in a direction perpendicular to the longitudinal direction. In the drawing, 1 ... electrodeless arc tube 2 ... microwave cavity 3 ... microwave cavity wall 4 ... slot as coupling means 5 ... waveguide 6 ... magnetron as microwave generation means 12 ... ventilation Pipe 13 …… Blowing means

Claims (1)

(57) [Claims] 1. A rod-shaped electrodeless arc tube in which a light-emitting material is sealed, a microwave cavity wall forming a microwave cavity in which the electroless arc tube is arranged, and a microwave coupled to the microwave cavity. A microwave coupling means, a microwave waveguide, and a microwave generation means, and a light-transmitting ventilation pipe arranged around the rod-shaped electrodeless light emitting tube; A microwave-excited electrodeless light-emitting device, comprising a blower for sending wind.