JPH06168708A - Electrodeless discharge lamp - Google Patents

Abstract

PURPOSE:To improve luminous efficiency free of temperature by exciting and illuminating the discharge gas forming an eximer with the high-frequency electromagnetic field. CONSTITUTION:When a high-frequency current generated by a power source 4 is fed to the induction coil 3 of an electrodeless discharge lamp, the electromagnetic field is induced in a bulb 1, and the discharge gas 2 forming an eximer in the bulb 1 is excited and illuminated. The luminous wavelength differs according to the type of the eximer. The gas containing chlorine rarely reacted with the bulb 1 and the rare gas is used for the discharge gas forming the eximer. Phosphers converting the ultraviolet rays into the visible light are coated on the inner face of the bulb 1. A temperature-free illumination light source having good luminous efficiency is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrodeless discharge lamp which does not have an electrode inside the bulb and which excites and emits discharge gas inside the bulb by a high frequency electromagnetic field from the outside.

[0002]

2. Description of the Related Art In recent years, electrodeless fluorescent lamps have been put to practical use. In this lamp, a high-frequency current is passed through an induction coil arranged in the vicinity of a bulb in which a discharge gas is sealed, and the generated induction electromagnetic field excites the discharge gas in the bulb to emit light.

FIG. 3 shows an example of this. 13.56 MHz output from a high frequency power source 4 is output to an induction coil 3 arranged in the vicinity of a bulb 1 containing several torr of argon and mercury.
The high-frequency current of the
This is an electrodeless fluorescent lamp that excites mercury atoms therein to emit ultraviolet rays of 254 nm and irradiates the fluorescent substance 5 coated on the inner surface of the bulb 1 with the ultraviolet rays to obtain visible light.

In FIG. 3, reference numeral 6 denotes an apparatus body made of a conductor, which removes radiation noise generated from the lamp and the high frequency power source 4. Reference numeral 7 is an electromagnetic shield means composed of a conductive mesh, which transmits the irradiation light from the lamp and prevents noise leakage from the irradiation surface.

Since this electrodeless fluorescent lamp has no electrode inside the bulb 1, there is no fear of electrode breakage and it has a long life. Another feature is that the shape of the lamp can be freely designed.

[0006]

By the way, when mercury is used as the discharge gas, the lamp characteristics are regulated by the mercury vapor pressure in the bulb, and this mercury vapor pressure is determined by the temperature of the coldest spot of the lamp. This is well known. In the low-pressure discharge lamp using mercury, the temperature of the coldest spot is about 40
It becomes the maximum luminous efficiency at ° C, and the luminous efficiency decreases at low temperature and high temperature.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an electrodeless discharge lamp having excellent temperature characteristics and good emission efficiency.

[0008]

In order to solve the above problems, the present invention relates to an electrodeless discharge lamp that excites and emits a discharge gas enclosed in a light-transmissive bulb by a high frequency electromagnetic field. The discharge gas for forming the excimer is characterized in that the discharge gas for forming the excimer is a gas containing a rare gas and chlorine. According to the third aspect of the invention, the inner surface of the bulb is coated with a phosphor that converts ultraviolet rays into visible light.

[0009]

According to the invention described in claim 1, since the discharge gas forming the excimer is excited to emit light by the high frequency electromagnetic field, the temperature is free and the luminous efficiency is good. Further, by selecting a gas, light emission of a desired wavelength can be obtained.

According to the second aspect of the present invention, since the discharge gas forming the excimer is a gas containing chlorine and a rare gas, which rarely react with the bulb, the decrease in the emission efficiency due to the decrease in the gas is small and the life is long. become.

According to the third aspect of the present invention, since the fluorescent substance for converting ultraviolet rays into visible light is coated on the inner surface of the bulb, visible light can be obtained even if the excimer emits ultraviolet rays, and excimer and fluorescent light are emitted. By appropriately selecting the combination of bodies, it is possible to realize a conversion efficiency superior to the conversion efficiency of the phosphor of the mercury resonance line of 254 nm of the low-pressure fluorescent lamp, and it is possible to provide a temperature-free illumination light source having excellent emission efficiency. Further, by changing the phosphor, any luminescent color can be obtained.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention, in which 1 is a valve made of a translucent material.
A discharge gas 2 that forms an excimer is enclosed inside. Reference numeral 3 denotes an induction coil wound around the outer periphery of the valve 1. In this embodiment, the induction coil 3 is wound 3 turns, but the number of turns is not particularly limited and it is wound 1 or more turns. Just do it. Reference numeral 4 is a high frequency power source for supplying a high frequency current to the induction coil 3.

When a high-frequency current generated from a high-frequency power source 4 is passed through the induction coil 3 of the electrodeless discharge lamp thus constructed, an electromagnetic field is induced in the bulb 1 and the bulb 1
The discharge gas 2 forming the excimer therein is excited to emit light. The emission wavelength depends on the type of excimer. The following table shows excimers and some of their emission wavelengths.

[0014]

[Table 1] As an example, Xe, HCl, and Ne are used as total gas pressure and
Fig. 2 shows the emission spectrum of the case in which several tens of Torr are filled from Torr
Shown in. Although Ne was used as the buffer gas, other rare gases may be used. The bulb 1 is made of quartz and is designed to transmit ultraviolet rays around 300 nm. The high frequency power source 4 was continuously oscillated at an oscillation frequency of 13.56 MHz. As is clear from FIG. 2, a strong emission spectrum of XeCl excimer is obtained at 308 nm.

[0015]

As described above, according to the present invention, since the discharge gas forming the excimer is excited to emit light by the high frequency electromagnetic field, it is possible to provide an electrodeless discharge lamp which is temperature-free and has a high luminous efficiency. Further, by selecting the discharge gas, it is possible to obtain light emission of a desired wavelength, which is effective as an ultraviolet light source.

Further, when the discharge gas forming the excimer is a gas containing chlorine and a rare gas, which rarely react with the bulb, as in the second aspect of the present invention, the decrease in the emission efficiency due to the decrease in the gas is small and the discharge gas is long. It will reach the end of life.

Furthermore, when the fluorescent substance is applied to the inner surface of the bulb and the combination of the excimer and the fluorescent substance is appropriately selected as in the invention described in claim 3, conversion of the fluorescent substance of the mercury resonance line 254 nm of the low pressure fluorescent lamp is converted. It is possible to realize a conversion efficiency superior to the efficiency and to provide a temperature-free illumination light source having excellent luminous efficiency.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional front view showing an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing an emission spectrum according to an example of the present invention.

FIG. 3 is a partial cross-sectional front view showing a conventional example.

[Explanation of symbols]

 1 valve 2 discharge gas 3 induction coil 4 high frequency power supply

Claims (3)

[Claims] 1. An electrodeless discharge lamp which excites and emits a discharge gas sealed in a translucent bulb by a high frequency electromagnetic field, wherein the discharge gas is a discharge gas forming an excimer. Discharge lamp. 2. The electrodeless discharge lamp according to claim 1, wherein the discharge gas forming the excimer is a gas containing a rare gas and chlorine. 3. The electrodeless discharge lamp according to claim 1, wherein the inner surface of the bulb is coated with a phosphor that converts ultraviolet rays into visible light.