JPH01292743A - Electrodeless discharge lamp - Google Patents

Abstract

PURPOSE:To obtain a small-size high output to improve luminous efficiency by forming an internal bulb inside to which fluorescent material is applied in the same airtight space as that of an external bulb and sealing discharge gas in it, and then, installing a dielectric coil which causes a high frequency magnetic field to occur in close vicinity of the internal bulb. CONSTITUTION:A lamp 10 is of a duplex tube structure consisting of an internal bulb 11 and an external bulb 12, the internal bulb 11 is translucent and nearly spherical and has an opening 13 at a part of it, and fluorescent material 14 is applied to its internal wall surface. An external bulb 12 is formed with translucent material so as to enclose the internal bulb 11, and the inside of the external bulb 12 makes the same airtight space with the inside of the internal bulb 11 through the opening 13. Mercury and rare gas are sealed in that airtight space, and a dielectric coil 15 is wound round the external circumference of the internal bulb 11, and a high frequency oscillator is installed in proper order inside base 16. Thereby, a light emission section is the internal bulb 11 so that the lamp is one in a small size and can obtain a high luminance, and as it is of a duplex tube structure, the coldest point temperature does not excessively increase so that the luminous efficiency can be kept high.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrodeless discharge lamp without a filament electrode.

[Prior Art] Conventionally, fluorescent lamps have been provided in which mercury atoms are excited by arc discharge to emit ultraviolet rays, and visible light is obtained by irradiating the phosphor I with the ultraviolet rays. However, this type of fluorescent lamp has a relatively short life and low efficiency. To solve this problem, electrodeless discharge lamps with longer lifespan and higher efficiency have been proposed for about 10 years, and are disclosed, for example, in Japanese Patent Application Laid-Open No. 78766/1983.

By the way, this type of electrodeless discharge lamp emits ultraviolet rays and visible light by applying a high-frequency electromagnetic field to excite low-pressure gas atoms and causing them to discharge inductively.The phosphor layer is irradiated with ultraviolet rays. It is designed to convert into visible light, but as shown in Figure 3, the pulp 2 of lamp 1
Since the coil 3 that provides a high-frequency electromagnetic field inside the bulb is disposed via the core 4, and the phosphor 5 is coated on the inner wall surface of the bulb 2, the overall dimensions of the lamp l, especially the light emitting surface area, are reduced. growing. This means that when this lamp 1 is used as a light source for a fixture for the purpose of controlling light distribution, such as a spotlight or a downlight, it is difficult to optically design a reflector, etc., and the reflector and the fixture itself become very large. . In addition, since the surface brightness is low, even when combined with a lens glove, etc., it produces a so-called sparkling feeling, which greatly limits its use.

Further, according to the lamp disclosed in Japanese Utility Model Application Publication No. 61-71957, as shown in FIG. The surface area is small, making it possible to create a compact, high-output light source.

[Problems to be Solved by the Invention] However, in such a lamp 1, the load on the tube wall is high, and the temperature at the coldest point increases excessively. Therefore, in the conventional example described above, the exhaust pipe 6 is left in a part of the valve 2 in the same space as the inside of the valve, and the tip thereof is set as the coldest point. 7, the length of the exhaust pipe 6 is limited due to the restriction. Furthermore, the temperature at the coldest point rises due to heat generation from the oscillation circuit 7. Incidentally, in lamps such as fluorescent lamps, in which mercury is sealed inside and the ultraviolet rays generated by the ionization are converted into visible light by the phosphor, the luminous efficiency is determined by the temperature of the lamp's coldest point. It is well known that it is determined. Normally, the coldest point temperature at which the maximum efficiency is achieved is around 40° C., but in the conventional example described above, the coldest point temperature reaches 60° C. or more, which causes a problem in that the luminous efficiency is significantly reduced.

The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide an electrodeless discharge lamp that is small in size and has high output, and does not cause the coldest point temperature to rise excessively, that is, has good luminous efficiency. be.

[Means for Solving the Problems] An electrodeless discharge lamp according to the present invention includes an inner bulb having a light-transmitting property and having a wall surface coated with a phosphor, and a light-transmitting lamp formed so as to surround the inner pulp. This is an electrodeless discharge lamp with a double-tube structure consisting of an outer bulb having a magnetic field, wherein the inner bulb is formed in the same airtight space as the outer bulb, and the airtight space is filled with a gas to be discharged. , and an induction coil that generates a high-frequency electromagnetic field is disposed close to the inner valve.

[Embodiment] Fig. 1 shows an embodiment of the present invention, in which the lamp 10 has a double tube structure consisting of an inner bulb 11 and an outer bulb 12, and the inner bulb 11 is translucent and has a substantially spherical shape. , has an opening 13 in a part thereof, and a phosphor 14 is coated on the inner wall surface.

The outer bulb 12 is made of a translucent material so as to surround the inner bulb 11. Further, the inside of the outer pulp 12 is the same airtight space as the inside of the inner valve 11 via the opening 13, and the airtight space is filled with mercury and a rare gas. Further, an induction coil 15 is wound around the outer circumference of the inner valve 11. A metal base 16 is generally fixed to the bottom of the outer bulb 12, and a cap 17 is provided at the center of the bottom of the base 16. Furthermore, a high frequency oscillator (not shown) is arranged inside the base 16.
The input end of the high frequency oscillator is connected to the base 17, and the output end is connected to both ends of the induction coil 15. The high-frequency oscillator performs high-frequency oscillation using a DC power source obtained by rectifying a commercial power source, and its frequency is in the M 1 OM Hz band.

In the electrodeless discharge lamp configured in this manner, a high frequency electromagnetic field is generated in the vicinity of the coil 15 by a high frequency current flowing through the coil 15, and gaseous electrons of the discharge gas sealed inside the outer bulb 12 are excited and discharged. Ultraviolet light is emitted.

Further, the ultraviolet rays emitted around the inner circumference of the coil 15 (that is, inside the inner bulb 11 and between the inner bulb 11 and the outer pulp 12) are converted into visible light by the phosphor 14 applied to the inner bulb 11, It is radiated out of the outer bulb 12 directly or indirectly. At this time, the inner valve 11 and the outer valve 12
In addition to ultraviolet rays, visible light from mercury is also emitted outside the outer bulb 12 along the same path as above, but this amount is much smaller than the visible light caused by the conversion of the ultraviolet rays by the phosphor 14. It is well known that there are few In addition, outer pulp 1
By forming 2 with glass that does not transmit ultraviolet rays,
No ultraviolet light is emitted outside the outer bulb 12.

Therefore, the light-emitting portion of the lamp 10 is approximately equivalent to the size of the inner bulb 11, and by appropriately designing the size of the inner pulp 11, an electrodeless discharge lamp with a substantially small light-emitting surface area is possible. . Also, although the coldest point depends on the usage condition and usage environment of the lamp 10, the tip of the lamp 10, that is, the outer bulb 12, has a value close to the optimal coldest point, unlike the inner bulb 11, which is extremely hot. Luminous efficiency is maintained at maximum.

The electrodeless discharge lamp according to the above embodiment allows a lamp with an ultra-small light emitting part, and is effective in designing a fixture such as a spotlight that requires light distribution control. In addition, in such applications, since the lighting is directed downward for fishing on a boat, the coldest point occurs at the bottom when the equipment is attached, which is the optimum coldest point and the luminous efficiency is maximized.

Next, FIG. 2 shows a different embodiment of the present invention, which differs from the previous embodiment in that the coil 15 is disposed inside the inner valve 11, and the inner valve 11 is located at the lower end (base 16). It has an opening 13 on the side), and a fluorescent substance 14 is coated on the inner wall surface as in the previous embodiment. Further, a reflecting mirror 18 is disposed around the outer periphery of the open end of the inner bulb 11, and its reflecting surface faces the tip side of the lamp 10.

According to this embodiment, there is no vignetting (photodeterioration) caused by the coil 15 in the lamp light emitting part, and there is no vignetting (photodeterioration) in the lamp light emitting part.
By simply inserting the coil 17, it can be used as a reflex type device, and in that case, the shadow of the coil 15 is not projected on the irradiation surface, and extremely good illumination can be provided.

In each of the above embodiments, heat resistance can be further improved by using quartz glass for the inner bulb 11. Therefore, an ultra-high output lamp having an ultra-compact light emitting part is possible, and impurities are precipitated from the inner pulp 11 due to high temperatures, etc., and the inner bulb 11. It is possible to prevent the surface of the outer bulb 12 from turning black. Furthermore, if a mesh-shaped shield body is provided in the space between the outer bulb 12 and the inner bulb 11 or on the inner wall surface of the outer bulb 12, for example, leakage noise can be reduced. Furthermore, the coldest point may of course be provided in a part of the exhaust pipe as in the conventional example, and the phosphor 14 may also be coated on both the inner and outer walls of the inner bulb 11. .

[Effects of the Invention] As described above, the present invention comprises an inner pulp having a translucent property and whose wall surface is coated with a phosphor, and an outer bulb having a translucent property formed to surround the inner bulb. An electrodeless discharge lamp with a double tube structure, the interior of the inner bulb is formed in the same airtight space as the outer bulb, the airtight space is filled with a gas to be discharged, and a high-frequency electromagnetic field is It is characterized by an induction coil that generates a It can provide a light source suitable for uses such as lights and downlights. Furthermore, because of the double tube structure that forms the same airtight space, even though the light emitting part is small, the temperature at the coldest point does not rise excessively, and the light emitting efficiency can be maintained at a high level.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional front view showing one embodiment of the present invention, FIG. 2 is a partially sectional front view showing a different embodiment of the present invention,
3 and 4 each show a conventional example, with FIG. 3 being a partially sectional front view and FIG. 4 being a schematic configuration diagram. 11...Inner valve, 12...Outer pulp, 13...
Opening, 14... Fluorescent material, 15... Induction coil.

Claims (1)

[Claims] (1) Electrodeless discharge with a double tube structure consisting of a translucent inner bulb whose wall surface is coated with phosphor and an outer translucent bulb surrounding the inner bulb. In the lamp, the interior of the inner bulb is formed in the same airtight space as the outer bulb, a discharge gas is sealed in the airtight space, and an induction coil that generates a high-frequency electromagnetic field is located in the inner bulb. An electrodeless discharge lamp characterized in that the lamps are arranged in close proximity to each other.