JP2782794B2 - Electrodeless discharge lamp - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrodeless discharge lamp that has no electrodes inside the lamp and excites and emits a discharge gas inside the lamp by an external high-frequency electromagnetic field.

[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.
Although there are various uses, it is considered to be used as a light source such as a lamp used at a high place, such as an aviation obstacle light, or an indicator light used in a cold region.

Among such electrodeless discharge lamps, for example,
In the lamp disclosed in Japanese Patent Application Laid-Open No. 57-78766, as shown in FIG. 10, a bulb 9 is formed so as to cover the air-core coil 8, and an electromagnetic field generated by applying a high-frequency current to the air-core coil 8 is generated. Discharges the mercury vapor in the bulb 9, and the magnetic field generated by the cylindrical coil used here is the strongest in the interior. In this example, however, there is no discharge space in that part, and the coil is exclusively used outside the coil. The valve 9 is formed in such a manner as to utilize the magnetic field.

Further, the lamps disclosed in JP-A-58-68862 and JP-A-58-68863 are low-pressure rare gas discharge lamps using neon light emission with electrodes, and such discharge lamps use a neon rare gas. When used at the most efficient gas pressure (several / 10 Torr) for light emission, the electrode material applied to the electrodes is greatly consumed and the life is significantly shortened. When a cold cathode is used instead of a hot cathode as an electrode, the size of the electrode part becomes large, and it is difficult to obtain a small light source part.

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

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a high-frequency current to an induction coil wound along the outer peripheral wall of a light-transmissive bulb, so that mercury sealed in the bulb can be obtained. In an electrodeless discharge lamp formed by exciting and emitting vapor, an ultraviolet-excited red light-emitting phosphor is applied to the inner wall surface of the bulb, and neon gas is added to the mercury vapor in the bulb at 0.3 to 3.0 Torr. It is characterized by being enclosed.

Embodiment 1 FIGS. 1 and 2 show a first embodiment of the present invention, wherein 1 is a spherical bulb, which is airtight and translucent, and has an inner wall surface. The phosphor 2 is applied. Further, mercury as a discharge gas is enclosed in the bulb 1 and neon gas is additionally enclosed therein. Here, the phosphor 2 is selected to convert ultraviolet light into red visible light. The amount of neon gas charged is 0.3 to 3.0 To
rr is preferred. Reference numeral 3 denotes an induction coil wound along the outer peripheral wall of the bulb 1, and reference numeral 4 denotes a high-frequency power supply for supplying a high-frequency current to the induction coil 3.

When a high-frequency current is applied to the induction coil 3 of the electrodeless discharge lamp configured as described above, 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 light mainly having a wavelength of 254 nm is converted into visible light by the phosphor 2 to emit red light mainly having a wavelength of 610 nm. At this time, the neon gas in the bulb 1 has a role 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 gaseous mercury to maintain the mercury discharge and the discharge is maintained by neon. In this case, red emission line emission around 640 nm of neon excitation emission is used.

At this time, the gas pressure of the enclosed neon gas becomes a problem. FIG. 3 shows the relationship between the light output and the starting voltage with respect to the gas pressure. As the gas pressure decreases, the light output increases, but the starting voltage also increases, and when the gas pressure is further reduced below 0.3 Torr. Starting is difficult. When the gas pressure is set to 3.0 Torr or more, the starting becomes easier, but the light output is reduced. Therefore, it can be said that 0.3 to 3.0 Torr is an appropriate gas pressure.
At such a relatively low gas pressure, in the case of a discharge lamp with electrodes, the emitter material of the electrodes is scattered and the life of the lamp is shortened. However, since the present invention is electrodeless, such a problem does not occur.

4 to 8 are spectral distribution diagrams of the electrodeless discharge lamp according to the present embodiment, and FIG.
-30 ° C, Fig. 5 shows the case of ambient temperature Ta = -15 ° C, Fig. 6 shows the case of ambient temperature Ta = 0 ° C, Fig. 7 shows the case of ambient temperature Ta = 25 ° C, and Fig. 8 shows the case of ambient temperature Ta = 45 ° C. Are respectively shown. The spectral intensities shown in FIGS. 7 and 8 are reduced. As can be seen, an electrodeless discharge lamp containing 0.3 to 3.0 Torr of neon gas in addition to mercury vapor can provide a substantially constant red light output over a wide temperature range from low frequency temperature to high ambient temperature. I understand.

[Example 2] In this example, in addition to the sealing gas in Example 1,
A small amount (for example, about 1%) of argon gas is sealed in neon so that the total gas pressure is 0.3 Torr or less, and other configurations are the same as those of the first embodiment. is there.

With this configuration, the lamp can be started at a relatively low starting voltage by utilizing the neon-argon penning effect even at a gas pressure lower than that of the first embodiment.

Third Embodiment FIG. 9 shows a third embodiment of the present invention. The difference from the first embodiment is that a temperature control means 5 capable of changing the valve temperature is provided on the outer wall surface of the valve 1. Since other configurations are the same as those of the first embodiment, the same components are denoted by the same reference numerals and description thereof will be omitted.

With this configuration, the coldest point in the valve 1 can be changed. Mercury vapor pressure is valve 1
For example, if the temperature is extremely low, neon red light emission is generated, and the fluorescent material applied to the inner wall of the bulb 1 can be selected to cool all colors. It can be obtained by increasing the point temperature.

[Effects of the Invention] As described above, according to the present invention, a high-frequency current is applied to an induction coil wound along the outer peripheral wall of a light-transmissive bulb, thereby exciting and emitting mercury vapor sealed in the bulb. In the electrodeless discharge lamp, a red-light-emitting phosphor excited by ultraviolet light is applied to the inner wall surface of the bulb, and neon gas is added to the mercury vapor at 0.3 to 3.0 Torr and sealed in the bulb so that the temperature is low. In some cases, efficient single light emission of the sealed gas can be used, and at room temperature, light emission from the phosphor by mercury vapor can be used. Therefore, according to the present invention, a substantially constant red light output 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 the drawings]

FIG. 1 is a simplified diagram showing an embodiment of the present invention, FIG. 2 is a cross-sectional view of the same bulb, 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 the 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. Bulb 2. Phosphor 3. Induction coil

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masahiro Higashikawa 1048 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Works Co., Ltd. (56) References JP-A-63-160150 (JP, A) JP-A-63-232254 (JP, A) JP-A-53-46181 (JP, A) JP-A-62-243238 (JP, A)

Claims (2)

(57) [Claims] 1. An electrodeless discharge lamp in which a high-frequency current is applied to an induction coil wound along an outer peripheral wall of a translucent bulb to excite and emit mercury vapor sealed in the bulb. An electrodeless discharge lamp characterized in that an ultraviolet-excited red light-emitting phosphor is applied to an inner wall surface of a bulb and neon gas is filled in the bulb in an amount of 0.3 to 3.0 Torr in addition to the mercury vapor. 2. An electrodeless discharge lamp in which a high-frequency current is applied to an induction coil wound along an outer peripheral wall of a light-transmissive bulb to excite and emit light of mercury vapor sealed in the bulb. Electrodeless discharge characterized in that a red light-emitting phosphor excited by ultraviolet light is applied to the inner wall surface of the bulb, and a mixed gas of neon and argon is added to the mercury vapor at 0.3 Torr or less and sealed in the bulb. lamp.