JPH0650629B2 - Electrodeless discharge lamp - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrodeless discharge lamp that has no electrodes inside the lamp and that excites and emits discharge gas inside the lamp by a high frequency electromagnetic field from the outside.

[Prior Art] Conventionally, electrodeless discharge lamps have been researched and developed in various places because of their features such as small size, high output, and long life. There are various uses, but for example, it is considered to be used as a light source such as a lighting device used at a high place such as an aviation obstruction light or an indicator light used in a cold region.

Among such electrodeless discharge lamps, for example, Japanese Patent Laid-Open No.
In the lamp disclosed in JP-A-7-78766,
As shown in the figure, a valve 9 is formed so as to cover the air-core coil 8, and the mercury vapor in the valve 9 is discharged by an electromagnetic field generated by passing a high-frequency current through the air-core coil 8. The magnetic field generated by the cylindrical coil used in the above is the strongest inside, but in this example, there is no discharge space in that part, and the valve 9 is formed exclusively by using the magnetic field outside the coil. .

In addition, JP-A-58-68862 and JP-A-58-6882
The lamp disclosed in Japanese Patent No. 68863 is a low-pressure rare gas discharge lamp that utilizes neon light emission with an electrode, and such a discharge lamp has the most efficient gas pressure (several / several) in neon rare gas light emission.
If it is used at 10 Torr), the electrode material applied to the electrode is heavily consumed and the life is shortened remarkably. If the cold cathode is used as the electrode instead of the hot cathode, the electrode portion becomes large and it is difficult to obtain a small light source portion.

[Problems to be Solved by the Invention] The present invention has been made in view of the above problems, and an object of the present invention is, for example, from a low ambient temperature such as −30 ° C. to a high ambient temperature such as 60 ° C. It is an object of the present invention to provide an electrodeless discharge lamp which can obtain a desired amount of light in a wide temperature range and has a very long life.

[Means for Solving the Problems] In order to solve the above problems, a high-frequency current is passed through an induction coil wound along the outer peripheral wall of a translucent bulb to excite the mercury vapor enclosed in the bulb. In an electrodeless discharge lamp that emits light, a fluorescent material is applied to the inner wall surface of the bulb, and a gas exhibiting excited light emission of substantially the same color as the emission color of the fluorescent material is added to the mercury vapor in the bulb. It is characterized by being enclosed.

[Embodiment 1] FIG. 1 and FIG. 2 show a first embodiment of the present invention, in which reference numeral 1 denotes a spherical bulb, which is airtight and transparent and has an inner wall surface. The phosphor 2 is applied. Further, mercury is enclosed as a discharge gas inside the bulb 1, and neon gas is additionally enclosed therein. The enclosed amount of neon gas is, for example, an amount that allows only neon to emit light by electrodeless discharge without mercury in the bulb 1. Reference numeral 3 is an induction coil wound along the outer peripheral wall of the valve 1, and 4 is a high frequency power source for supplying a high frequency current to the induction coil 3.

Induction coil 3 of the electrodeless discharge lamp configured as described above
When a high-frequency current is applied to, an electromagnetic field is induced. For example, at an ambient temperature of 0 ° C or higher, the discharge gas is mercury,
The mercury atoms are excited to emit light, and the generated ultraviolet rays having a main component of 254 nm are converted into visible light by the fluorescent body 2 to emit red light having a main component of 610 nm. At this time, the neon gas in the bulb 1 serves as a buffer gas, and controls the electron energy to a value at which mercury atoms are easily excited.

At lower ambient temperatures, there is not enough mercury in the gas to sustain a mercury discharge and the discharge is maintained by neon. In this case, red line emission around 640 nm of neon excited emission is used.

FIG. 3 is a graph showing the characteristics of light output with respect to ambient temperature. When the enclosed gas is neon and mercury (Ne + in the figure).
Hg) and argon and mercury (Ar + Hg). 4 to 8 are spectrum distribution diagrams of the electrodeless discharge lamp according to the present embodiment.
The figure shows the ambient temperature Ta = −30 ° C., and FIG. 5 shows the ambient temperature Ta =
-15 ° C., FIG. 6 shows the ambient temperature Ta = 0 ° C., FIG. 7 shows the ambient temperature Ta = 25 ° C., and FIG. 8 shows the ambient temperature Ta = 45 ° C. The spectral intensities shown in FIGS. 7 and 8 are reduced. As can be seen from the above, the lamp in which neon and mercury are enclosed has a very good rise at a low temperature.

Example 2 The present example is characterized in that the filling gas in the above example is mercury vapor and xenon gas, and the other configurations are the same as in the above example. If the fluorescent substance 2 applied to the inner wall of the bulb 1 with such a constitution is adapted to convert the ultraviolet ray mainly composed of 254 nm generated by mercury excitation into a white color of 400 to 600 nm, white light is emitted even at a low temperature. An electrodeless discharge lamp with high strength can be obtained.

[Third Embodiment] The present embodiment is characterized in that a small amount (for example, about 1%) of argon gas is filled with neon in addition to the filled gas in the first embodiment. Example 1
Is the same as. With this structure, it is possible to start the lamp with a relatively low starting voltage by utilizing the Penning effect between neon and argon even at a very low temperature.

[Embodiment 4] FIG. 9 shows a fourth embodiment of the present invention.
The different point from that is that the temperature control means 5 capable of changing the valve temperature is provided on the outer wall surface of the valve 1, and the other configurations are the same as those of the first embodiment. The description is omitted.

With this configuration, the coldest spot in the valve 1 can be changed. Since the mercury vapor pressure follows the temperature of the coldest point in the bulb 1, for example, if the temperature is extremely low, red light emission of neon occurs, and by selecting the fluorescent substance to be applied to the inner wall of the bulb 1. , Any color can be obtained by raising the coldest spot temperature.

EFFECTS OF THE INVENTION As described above, the present invention excites and emits mercury vapor enclosed in the bulb by energizing the induction coil wound along the outer peripheral wall of the translucent bulb with a high-frequency current. In an electrodeless discharge lamp consisting of, while applying a fluorescent substance to the inner wall surface of the bulb, a gas exhibiting excited light emission of substantially the same color as the emission color of the fluorescent substance was added to the mercury vapor and sealed in the bulb. As a result, the single emission of the enclosed gas can be used at low temperature, and the emission of light by mercury vapor through the phosphor can be used at normal temperature. Therefore, according to the present invention, a desired amount of light can be obtained in a wide temperature range from a low ambient temperature to a high ambient temperature, and an electrodeless discharge lamp having an extremely long life can be provided.

[Brief description of drawings]

FIG. 1 is a simplified diagram showing an embodiment of the present invention, FIG. 2 is a sectional view of the bulb shown above, FIG. 3 is a diagram showing characteristics of light output with respect to ambient temperature, and FIGS. FIG. 9 is a spectrum distribution diagram of an electrodeless discharge lamp according to the present invention, FIG. 9 is a simplified diagram showing a different embodiment of the present invention, and FIG. 10 is a partial cross-sectional front view showing a conventional example. 1 ... Valve 2 ... Fluorescent body 3 ... Induction coil

Claims (3)

[Claims] 1. An electrodeless discharge lamp in which mercury vapor enclosed in the bulb is excited to emit light by passing a high-frequency current through an induction coil wound along the outer peripheral wall of the transparent bulb. An electrodeless discharge, characterized in that a fluorescent substance is applied to the inner wall surface of the bulb, and a gas exhibiting excited light emission of substantially the same color as the emission color of the fluorescent substance is added to the mercury vapor and sealed in the bulb. lamp. 2. The electrodeless discharge lamp according to claim 1, wherein the phosphor is a phosphor that emits red light, and the enclosed gas is neon. 3. The electrodeless discharge lamp according to claim 1, wherein the phosphor is a phosphor that emits white light, and the enclosed gas is xenon.