JPH06243825A - Metal halide lamp - Google Patents

Abstract

PURPOSE:To obtain a lamp which increases the output intensity of ultraviolet ray, and has a long service life and an excellent performance, by adding and sealing a specific amount of mercury bromide in a luminous tube of a metal halide which uses only the luminous tube without using an outer tube. CONSTITUTION:This metal halide lamp has no outer tube to utilize the ultraviolet ray mainly less than 400nm, but it is formed of only a luminous tube 1 made of a quartz glass, main electrodes 2 are sealed at both ends of the tube 1, and the load of the luminous tube wall surface is set 20 to 80W/cm<2>. A metal halide of iodine, bromine, and the like, mercury as a buffer gas, and argon as a start assisting gas are sealed in the tube 1. Furthermore, adding to the metal halide, the mercury bromide HgBr2 to the total weight AX of the metal halide is sealed in the scope 0.2<=HgBr2/AX<=1.0. By adding and sealing a specific amount of mercury bromide in the luminous tube in such a way, the output intensity of the ultraviolet ray less than 400nm is increased, and a metal halide lamp with a long service life, and optimum as a light source for industrial apparatus can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal halide lamp which can be used without an outer tube, and more particularly to a metal halide lamp for curing an ultraviolet resin or a light source for medical equipment.

[0002]

2. Description of the Related Art In recent years, metal halide lamps that are used only as arc tubes without using an outer tube have been used as light sources for video equipment such as overhead projectors (OHP) and projectors, and optical equipment. Further, since the light distribution control as a lamp is easy and the condensing property is good, the application to industrial equipment such as a light source for ultraviolet resin curing or medical equipment is expanding.

The above-mentioned lamp has been developed as one utilizing visible light, and in consideration of application to industrial equipment utilizing ultraviolet rays such as resin curing, a lamp having a large ultraviolet ray output is required, Satisfactory results cannot be obtained with the conventional lamp additives or their addition amounts.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and increases the ultraviolet light output of a metal halide lamp used only with an arc tube without using an outer tube and has a long life and is optimal as a light source for industrial equipment. The purpose is to provide a simple metal halide lamp.

[0005]

The present invention is mainly applied to 400 nm.
It is composed of only an arc tube without an outer tube using the following ultraviolet rays, at least main electrodes are sealed at both ends, the wall surface load of the arc tube is 20 to 80 W / cm ² , and the luminescent metal is iodine.
In an arc tube sealed as a metal halide such as bromine, mercury bromide (HgBr2) is added to the above metal halide (AX) in an amount of 0.2≤HgBr2 / AX≤1. It is characterized in that it is filled in a range of 0, and a rare gas as a starting auxiliary gas and a mercury as a buffer gas are filled. Further, a reflecting mirror having a spherical surface, a spheroidal surface, a paraboloid of rotation, or a combination thereof is fixed to one end of the arc tube. Furthermore,
When the maximum inner diameter of the arc tube is d and the distance between the electrodes is 1, 1 / d is 1.5 or less.

[0006]

With the above construction, not only the ultraviolet ray output of 400 nm or less can be increased, but also the halogen cycle becomes active and devitrification and blackening of the arc tube are reduced. Further, by using it in combination with a reflecting mirror such as a paraboloid of revolution, a lamp with a reflecting mirror having good light distribution characteristics can be obtained. Furthermore, a compact lamp having excellent life characteristics can be obtained.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partial vertical side view of a small metal halide lamp. In the figure, reference numeral 1 is a quartz glass arc tube, which is formed into a substantially spherical shape and has a maximum inner diameter d of 9 mm, a maximum outer diameter of 11 mm, and an internal volume of about 0.5 cc. Is. Reference numerals 2 and 2 are main electrodes connected to both ends of the arc tube 1 at 3, 3 via molybdenum foils 4 and 4, and the distance l between the electrodes is 5 mm. Further, 5 is an external lead wire made of molybden, and 6 is an exhaust pipe tip-off portion.

In this arc tube, dysprosium iodide, neodymium iodide, and cesium iodide as light-emitting metals were filled in a total weight of 0.6 mg at a weight ratio of 4: 2: 3 and a buffer. A predetermined amount of mercury as a gas, and a predetermined amount of mercury bromide (HgBr2) together with 200 Torr of argon as a starting auxiliary gas are enclosed.

A metal halide lamp constructed as in the previous period was lit by alternating current with an input power of 150 W using a dedicated ballast, and a lighting test was conducted.

For comparison, a conventional lamp not containing mercury bromide was subjected to a lighting test, and the UV output of 365 nm or less was measured. As a result, the UV output after lighting for 500 hours fell to 50% or less. .

Then, a lighting test was conducted on seven kinds of lamps in which a predetermined amount of mercury bromide was filled in the metal halide (0.6 mg).
The measurement result of the ultraviolet output after lighting for a certain time was obtained. In addition, the said measured value shows the minimum value (relative value) of the ultraviolet intensity maintenance factor of 365 nm.

[Below margin]

[0012]

[Table 1]

As is clear from Table 1, a decrease in UV output can be prevented to some extent by adding and enclosing mercury bromide. However, in order to achieve a maintenance rate that is recognized to be effective, that is, a UV output maintenance rate of 70%, at least 0.6 mg of mercury bromide, that is, the amount of mercury bromide relative to the total weight of the metal halogen compound (AX). (HgB
It is necessary to encapsulate r ₂ ) within the range of 0.2 ≦ HgBr ₂ /AX≦1.0.

Further, it has been clarified from the above background and mercury beak that the vapor pressure in the arc tube becomes higher than that of the conventional lamp by adding and enclosing a predetermined amount of mercury bromide. This is because the increase in metal vapor pressure promotes uniform vapor pressure distribution in the arc tube,
It is also considered that the halogen cycle becomes active and the blackening or devitrification of the arc tube is suppressed, and the decrease in the ultraviolet light output is reduced.

Furthermore, since the vapor pressure in the arc tube can be increased to some extent by adding and sealing mercury bromide, the arc tube can be designed with a wall load lower than that of the conventional lamp (the arc tube capacity is reduced). Therefore, the degree of freedom in designing the lamp will be increased in consideration of the thermal effect of the arc tube.

Next, the ultraviolet output intensity at the start of lighting was measured, and the measurement results shown in Table 2 were obtained. The measured value is 36
The relative value of the ultraviolet output intensity of 5 nm is shown.

[Below margin]

[0017]

[Table 2]

As is clear from Table 2, the output intensity of ultraviolet rays is higher than that of the conventional lamps, and is maximum when the amount of mercury bromide enclosed is 0.6 to 0.9 mg. ing. However, considering the above life characteristics, an amount of mercury bromide of 0.9 mg, which causes a large decrease in ultraviolet ray output during the life, is not preferable.

Although the arc tube has been described in the above embodiment, one end of the arc tube is fixed to the garden part of the reflection boundary and used as a light source for optical fiber for curing the ultraviolet resin.

[0020]

As is apparent from the above description, according to the present invention, the ultraviolet ray output intensity of 400 nm or less is increased by enclosing and enclosing a predetermined amount of mercury bromide in the arc tube, and even after the lighting for a long time. A metal halide lamp that can maintain its output intensity, has a long life, and is easy to design an arc tube can be obtained. And it is most suitable as an industrial light source using an optical fiber.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of a metal halide lamp according to the present invention.

[Explanation of symbols]

 1 arc tube 2 main electrode 4 molybdenum foil

Claims (3)

[Claims] 1. Mainly composed of an arc tube without providing an outer tube utilizing ultraviolet rays of 400 nm or less, at least main electrodes being sealed at both ends, and an arc tube wall load of 20 to 80 W / cm.
^{In the} arc tube in which the luminescent metal is enclosed as a metal halide such as iodine or bromine, in addition to the metal halide, mercury bromide (HgBr2) is set to 0 with respect to the total weight of the metal halide (AX). .2 ≦ HgBr2 / AX ≦
A metal halide lamp which is filled in a range of 1.0 and which is filled with a rare gas as a starting auxiliary gas and mercury as a buffer gas. 2. A spherical surface, a spheroidal surface, and one end of the arc tube,
The metal halide lamp according to claim 1, wherein a reflecting mirror made of a paraboloid of revolution or a combination thereof is fixed. 3. The metal halide according to claim 1, wherein 1 / d is 1.5 or less when the maximum inner diameter of the arc tube is d and the distance between the electrodes is 1. lamp.