JPH07245082A - Metal vapor discharge lamp - Google Patents

Abstract

PURPOSE:To concentrate light energy to a an ultraviolet range of a specific wavelength to be the-optimum for photochemical reaction or paint drying by enclosing halogen, cobalt, and tin, each in a specific quantity, with rare gas in a light emission tube provided with an electrode. CONSTITUTION:A light emission tube 1 comprising heat-resistant transparent material such as quartz glass is provided with an electrode 2 to which external lead wires 4 are connected at both ends through metal foil 3. A sufficient quantity of mercury for maintaining arc discharge, and a proper quantity of rare gas, halogen, cobalt, and tin are enclosed in the tube 1. The quantity of halogen is 1.0X10<-5>-1.0X10<-8> gram-atom/cm<3> to an inner volume of the light emission tube 1, the total quantity of cobalt and tin is 1/2-3 at an atomic ratio to halogen, and the quantity of tin to cobalt is 1/20-1. Light energy can thus be concentrated to an ultraviolet range of a wavelength of 300-360nm which is the optimum for photochemical reaction and paint drying.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an ultraviolet metal vapor discharge lamp used as a light source for photochemical reactions and paint drying.

[0002]

2. Description of the Related Art A metal vapor discharge lamp filled with halogen, iron and tin together with a sufficient amount of mercury and an appropriate amount of rare gas to maintain an arc discharge inside an arc tube equipped with an electrode is used in the ultraviolet region, particularly 280 to 280. Because of its excellent luminous efficiency in the 420 nm region, it is often used as a light source for photochemical reactions and paint drying, instead of a high-pressure mercury lamp for ultraviolet light.

[0003]

In the conventional metal vapor discharge lamp containing iron and tin, as shown in FIG. 3, a large number of emission line spectra are concentrated in the 360 to 390 nm region, so that a specific range is defined as an effective wavelength region. It may not be effective as a photochemical reaction or a light source for drying paint. In particular, when a metal vapor discharge lamp containing iron and tin is used with an effective wavelength range of 300 to 360 nm, as shown in FIG. 3, a relatively high continuous spectrum including bright lines in the 360 to 420 nm range does not contribute to the reaction. However, there is a drawback that most of the light energy is wasted. Therefore, the present invention solves the above-mentioned conventional drawbacks, and an object of the present invention is to provide a metal vapor discharge lamp in which light energy is concentrated in a specific wavelength region of 300 to 360 nm.

[0004]

SUMMARY OF THE INVENTION The present invention encloses halogen, cobalt and tin with a sufficient amount of mercury and an appropriate amount of noble gas to maintain an arc discharge inside an arc tube equipped with electrodes. The filling amount was 1.0 × 10 ^{−5 to} 1.0 × 10 ⁻⁸ gram atom per 1 cm ^{3 of the} inner volume of the arc tube, and the total amount of cobalt and tin was 1 / atomic ratio with respect to the halogen atom.
2-3, and the atomic ratio of tin to cobalt is 1
By setting / 20 to 1, the light energy is concentrated in the ultraviolet region of wavelength 300 to 360 nm.

[0005]

The inventor has found that cobalt and tin are effective for concentrating light energy in the ultraviolet region of 300 to 360 nm, and as a result of research and study, the amount of cobalt, tin and halogen enclosed was set within a predetermined range. By stipulating,
It was confirmed that a relatively high continuous spectrum including emission lines was emitted over the ultraviolet region of 300 to 360 nm, and that the energy ratio in the other wavelength range was smaller.

The present invention will be described below with reference to the drawings. In FIG. 1, 1 is an arc tube made of a heat-resistant translucent material such as quartz glass, 2 is electrodes sealed at both ends of the arc tube, 3 is a metal foil, 4 is an external lead wire, 5 is an arc tube near the electrode Is a heat insulating film made of Al ₂ O ₃ or the like for keeping the tube wall temperature of the above at an optimum value. Further, the arc tube 1 is filled with a sufficient amount of mercury, an appropriate amount of rare gas and halogen, and cobalt and tin to maintain arc discharge.

Here, the halogen to be sealed in the arc tube is 1.0 × 10 ^{−5 to} 1.0 × 1 per 1 cm ³ of the internal volume of the arc tube.
^Specify 0 to ⁸ grams atom. If it is less than this range, the spectral energies of cobalt and tin are extremely reduced and become close to the spectrum of mere mercury discharge. If it is more than the above range, the starting voltage, re-ignition voltage and lamp voltage of the discharge lamp are increased and the electrical characteristics are become worse. Further, the total amount of cobalt and tin to be sealed in the arc tube is 1/2 to 3 in atomic ratio with respect to halogen.
The range of is desirable. If it is less than this range, sufficient UV output cannot be obtained. On the other hand, if it is larger than the above range, cobalt and tin adhere to the inside of the arc tube and cause dimming. Furthermore, the tin to be sealed in the arc tube must have an atomic ratio of 1/20 to 1 with respect to cobalt. When the amount of tin is less than the above range, cobalt enclosed in the arc tube evaporates and adheres to the inner wall of the tube to cause a blackening phenomenon, which causes dimming. If it exceeds the above range, the luminous efficiency of cobalt is lowered and the spectral distribution becomes extremely weak.

Table 1 shows the experimental results showing the reason why the atomic ratio of cobalt and tin should be limited to the above range. The lamps used in the experiment are shown in Table 1 with mercury and an appropriate amount of argon gas required to form an arc in an arc tube having an inner diameter of 20 mm and an internal volume of 42.4 cc, and a chemical equivalent iodine equivalent to the total amount of cobalt and tin. Thus, the amount of cobalt and tin enclosed is selected. As is clear from Table 1, when the atomic ratio of tin to cobalt is in the range of 1/20 to 1, most of the radiant energy is concentrated in the wavelength region of 300 to 360 nm and the lamp is lit, as shown in FIG. The spectral distribution characteristics were obtained.

[0009]

According to the present invention, by enclosing a predetermined amount of halogen, cobalt and tin together with mercury and a rare gas in the arc tube, it becomes possible to concentrate the light energy in the ultraviolet region of 300 to 360 mm, 300-360 mm
It is possible to obtain a high pressure metal discharge lamp that is optimal as a light source for photochemical reaction or coating drying in which the wavelength range is the effective wavelength range.

[Brief description of drawings]

FIG. 1 is a partially longitudinal side view of a metal vapor discharge lamp according to the present invention.

FIG. 2 is a spectral energy distribution diagram of the discharge lamp.

FIG. 3 is an energy distribution diagram of a conventional metal vapor discharge lamp.

[Explanation of symbols]

 1 arc tube 2 electrode 3 metal foil 4 external lead wire 5 heat insulating film

[Table 1]

Claims (1)

[Claims] 1. An arc tube equipped with an electrode is filled with halogen, cobalt and tin together with a sufficient amount of mercury and an appropriate amount of rare gas to maintain an arc discharge, and the enclosed amount of halogen is 1 cm of the internal volume of the arc tube. 1.0 x 10 ^-5 to 1.0 x per ³
A wavelength of 300 is obtained by setting the amount of cobalt and tin to 10 ⁻⁸ gram atom, the total amount of cobalt and tin in the atomic ratio of 1/2 to 3 with respect to the halogen atom, and the amount of tin to cobalt in the atomic ratio of 1/20 to 1. A metal vapor discharge lamp characterized by concentrating light energy in the ultraviolet region of up to 360 nm.