JPH02170340A - Discharge lamp without electrode - Google Patents

Abstract

PURPOSE:To obtain a desired light quantity in a wide temperature scope from a low to a high ambient temperatures by spreading a phosphor on the inner wall surface of a bulb, and adding a gas to present an exciting radiation almost in the same color as the luminous color of the phosphor to mercury vapor in the bulb and sealing up. CONSTITUTION:On the inner wall surface of a spherical bulb 1, a phosphor 2 is spread, mercury is sealed as a discharge gas in the bulb 1, and neon gas is sealed in addition. The sealing amount of the neon gas is the amount to enable the electrodeless discharge radiation only with the neon gas even though no mercury is sealed in the bulb 1, for example. By applying a high-frequency current to an induction coil 3, an electromagnetic field is induced, and the independent radiation of the sealed gas can be utilized at a low temperature, while the radiation of the neon vapor through the phosphor 2 is utilized at a normal temperature. Consequently, a desired light quantity can be obtained in a wide temperature scope from a low to a high ambient temperatures.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electrodeless discharge lamp that does not have electrodes inside the lamp, but excites a discharge gas inside the lamp to emit light using an external high-frequency electromagnetic field.

[Prior Art] Electrodeless discharge lamps have been researched and developed in various places since they have features such as small size, high output, and long life. There are various uses for it, but for example, it is being considered to be used as a light source for lighting equipment used at high places such as aircraft obstacle lights, and for indicator lights used in cold regions.

Among such electrodeless discharge lamps, for example,
In the lamp disclosed in Publication No. 7-78766, No. 10
As shown in the figure, a bulb 9 is formed to cover the air-core coil 8, and the mercury vapor inside the bulb 9 is discharged by the electromagnetic field generated by passing a high-frequency current through the air-core coil 8. The magnetic field produced by the cylindrical coil used in the cylindrical coil is strongest inside the coil, but in this example
There is no electric space, and the valve 9 is formed using only the magnetic field outside the coil.

Also, JP-A-58-68862 and JP-A-58-
The lamp disclosed in Japanese Patent No. 68863 is a low-pressure rare gas discharge lamp that has electrodes and uses neon light emission, and such a discharge lamp has a gas pressure (number /
When used at a temperature of 10 Torr), the electrode material coated on the electrode is rapidly consumed, resulting in a significantly shortened lifespan. If a cold cathode is used instead of a hot cathode as an electrode, the electrode portion becomes large, and it is also 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-mentioned problems, and its purpose is, for example, to reduce the ambient temperature from a low ambient temperature of -30'C to a high ambient temperature of 60'C. It is an object of the present invention to provide an electrodeless discharge lamp that can provide a desired amount of light in a wide temperature range up to 100 mL and has an extremely long life.

[Means for Solving the Problems] In order to solve the above problems, mercury vapor sealed within the light-transmitting bulb is excited by passing a high-frequency current through an induction coil wound along the outer peripheral wall of the light-transmitting bulb. In an electrodeless discharge lamp that emits light, a phosphor is coated on the inner wall surface of the bulb, and a gas that emits excited light having substantially the same color as the emission color of the phosphor is added to the mercury vapor in the bulb. It is characterized by being enclosed.

[Example 1] Figures 1 and 2 show a first example of the present invention, in which 1 is a spherical bulb that is airtight and translucent, and has an inner wall surface. A phosphor 2 is coated. Furthermore, the inside of the bulb 1 is filled with mercury and neon gas as a discharge gas. The amount of neon gas sealed is such that, for example, even if there is no mercury in the bulb 1, only neon can be emitted by electrodeless discharge. 3 is an induction coil wound along the outer circumferential wall of the bulb 1; 4 is a high-frequency power source that supplies a high-frequency current to the induction coil 3;

Induction coil 3 of the electrodeless discharge lamp configured in this way
When a high-frequency current is applied to the , 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 and emit light, and the generated ultraviolet rays mainly composed of 254nn+ are absorbed by the phosphor 2. Converted to visible light, 610n
It emits red light mainly composed of m. At this time, the neon gas in the bulb 1 serves as a buffer gas and controls the electron energy to a value that facilitates the excitation of mercury atoms.

If the ambient temperature is lower, there is not enough gaseous mercury to sustain a mercury discharge, and the discharge is sustained by neon. In this case, red bright line emission around 640 nm of neon excitation emission is used.

Figure 3 is a diagram showing the characteristics of light output with respect to ambient temperature, when the filled gas is neon and mercury (in the figure, Ne +
(denoted as Hg) and the case of argon and mercury (Ar+Hg). Moreover, FIGS. 4 to 8 are spectral distribution diagrams of the electrodeless discharge lamp according to this example, respectively.
The figure shows the ambient temperature Ta=-30℃, and the figure 5 shows the ambient temperature Ta=-30℃.
-15°C, FIG. 6 shows the case where the ambient temperature Ta=0°C, FIG. 7 shows the case where the ambient temperature Ta=25°C, and FIG. 8 shows the case where the ambient temperature Ta=45°C. Note that the spectral intensities shown in FIGS. 7 and 8 are scaled down. As can be seen from these, lamps filled with neon and mercury have a very good start-up at low temperatures.

[Example 2] This example is characterized in that the gases used in the previous example were mercury vapor and xenon gas, and the other configurations are the same as those of the previous example. With this configuration, the phosphor 2 coated on the inner wall of the bulb 1 is exposed to ultraviolet light of 400 to 600 nm, mainly 254 nm, generated by mercury excitation.
By using a material that converts to white light, it is possible to obtain an electrodeless discharge lamp that emits white light with high intensity even at low temperatures.

[Example 3] This example is characterized in that, in addition to the gas sealed in Example 1, a small amount (for example, about 1%) of argon gas is filled with respect to the neon. Example 1
It is similar to With this configuration, even at very low temperatures, the lamp can be started with a relatively low starting voltage by utilizing the Penning effect between neon and argon.

[Example 4] FIG. 9 shows a fourth example of the present invention.
The difference is that a temperature control means 5 that can change the valve temperature is provided on the outer wall surface of the valve l.The other configurations are the same as in Example 1, so the same components are given the same reference numerals. The explanation will be omitted.

With this configuration, it is possible to change the coldest point within the valve 1. Water 11i atmospheric pressure is valve 1
For example, if the temperature is set to a very low temperature, neon red light will be emitted, and by selecting the phosphor applied to the inner wall of the bulb 1, all colors can be made to follow the temperature of the coldest point inside the bulb. This can be obtained by increasing the point temperature.

[Effects of the Invention] As described above, the present invention applies a high-frequency current to an induction coil wound along the outer peripheral wall of a translucent bulb to excite the mercury vapor sealed in the bulb to emit light. In the electrodeless discharge lamp, a phosphor is coated on the inner wall surface of the bulb, and a gas that emits excited light having substantially the same color as the emission color of the phosphor is sealed in the bulb in addition to the mercury vapor. As a result, independent light emission from the injection gas can be used at low temperatures, and light emission via the phosphor of mercury vapor can be used at room temperatures. Therefore, according to the present invention, a desired amount of light can be obtained in a wide temperature range from low ambient temperature to high ambient temperature, and
It is possible to provide an electrodeless discharge lamp with an extremely long life.

[Brief explanation of the drawing]

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. 4 to 8 are respectively FIG. 9 is a spectral 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 partially sectional front view showing a conventional example. 1... Bulb 2... Fluorescent body 3... Induction coil Figure 1 Patent issued by Matsushita Electric Works Co., Ltd.

Claims (3)

[Claims] (1) An electrodeless discharge lamp in which mercury vapor sealed 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 light-transmitting bulb. An electrodeless discharge lamp characterized in that an inner wall surface is coated with a phosphor, and a gas that emits excited light having substantially the same color as the emission color of the phosphor is sealed in the bulb in addition to the mercury vapor. (2) The electrodeless discharge lamp according to claim 1, wherein the phosphor is a phosphor that emits red light, and the filled gas is neon. (3) The electrodeless discharge lamp according to claim 1, wherein the phosphor is a phosphor that emits white light, and the filled gas is xenon.