JPH09102278A - Manufacture of metal halide lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a long life of lamp, suppressing the going out at start of itself, the rise of starting voltage, and the blackening of a luminous tube, by lessening OH groups to be mixed in quartz to the utmost, and performing high-temperature vacuum furnace processing after processing, using a plasma torch for the processing of a quartz luminous tube. SOLUTION: Out of side pipe joint process, in the case of having performed processing by oxyhydrogen burner for both drawing process and joint process, OH groups mix in. Moreover, also in the next sealing process, likewise OH groups mix in. So, for the processing by hydrogen burner, the same process is to be performed, using a plasma torch, and then processing in vacuum furnace at high temperature is performed for fifteen minutes or less, whereby the average OH content of the quartz luminous tube can be made 1ppm or under. This way, by using a plasma torch, the reduction of the processing in vacuum furnace at high temperature and the sharp reduction of the OH content become possible. Hereby, a long life of lamp can be obtained by suppressing the going out at start of a lamp, or the rise of starting voltage, or the blackening or devitrification of the light emitting tube.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing method applied to a manufacturing process of a metal halide lamp, in which OH groups mixed in quartz are minimized.

[0002]

2. Description of the Related Art In recent years, metal halide lamps have been used for many purposes, particularly where high efficiency and high color rendering characteristics are utilized. However, in the manufacture of metal halide lamps, the oxyhydrogen burner conventionally used for processing quartz mixes OH groups into quartz during manufacturing. This OH group becomes hydrogen and is released when the lamp is lit after completion. The released hydrogen has a problem that it extinguishes at the time of starting the lamp, raises the starting voltage, causes an abnormality in the halogen cycle, and adversely affects the life characteristics of the lamp such as blackening and devitrification of the arc tube. Due to this problem, it is said that it has a shorter life than mercury lamps or high-pressure sodium lamps.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and minimizes the OH group mixed in quartz during the manufacturing process to extinguish the lamp at the time of starting the lamp and increase the starting voltage. It was made to suppress blackening and devitrification of the arc tube and to supply a long-life metal halide lamp.

[0004]

According to the present invention, a plasma torch is used instead of an oxyhydrogen burner for processing a quartz arc tube or a quartz outer tube in the process of manufacturing a metal halide lamp. The feature is that it is reduced as much as possible.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a plasma torch is used instead of an oxyhydrogen burner for processing a quartz arc tube or a quartz outer tube used in a metal halide lamp. By not using oxyhydrogen gas for processing the quartz tube in this way, the OH groups mixed in the quartz during processing are very small, and the lamp manufactured by the manufacturing method of the present invention is extinguished at the time of lamp starting and starting voltage. It is possible to supply a metal halide lamp having a long life by suppressing the rise in temperature, the blackening and devitrification of the arc tube.

[0006]

The details of the present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a diagram for explaining a method of manufacturing an unexhaust pipe of a metal halide lamp according to the present invention. First, the OH group content of the quartz tube used for processing was measured using the infrared transmission method. As a result, it was confirmed that the OH group content of the quartz tube was 1 ppm or less. As shown in FIG. 1, the method for manufacturing the unexhaust pipe of the metal halide lamp includes a side pipe connecting step (a) and a sealing step (b). First, the side tube process includes a drawing (tapering) process (a-1) and a joining process (a-2). In this step, OH groups are mixed due to the processing of the burner of oxyhydrogen. Next, in the sealing step (b), OH is also processed by the processing of the burner of oxyhydrogen.
There is a mixture of groups.

400 thus processed with an oxyhydrogen burner
A 0 W unexhaust pipe is shown in FIG. The OH group content in the quartz of the unsealed portion 1, the mold portion 2, the taper portion 3, and the main pipe portion 4 of the unexhaust pipe was measured by an infrared transmission method. When processed with an oxyhydrogen burner, the content of OH groups in each part of the unexhaust pipe is 13 ppm in the sealing part and 11 in the molding part.
ppm, taper portion 15 ppm, main portion 2.5 ppm.

Next, this sample quartz was subjected to a vacuum furnace treatment at 1000 ° C. to examine the removal of OH groups. The result is shown in FIG.
Shown in FIG. 3 shows the relationship between the processing time and the OH group content when the sample quartz was subjected to vacuum furnace processing at 1000 ° C.
8 ppm OH at taper even after vacuum furnace treatment for 6 hours
There is a group content, and each of the above parts is in a state before processing (1 pp
It took 32 hours or more to obtain m).

A similar test was conducted by changing the processing burner to a plasma torch. The result is shown in FIG. By using the plasma torch, each of the above parts could be brought to the state before processing (1 ppm) by the vacuum furnace treatment for 15 minutes.

Based on these results, the unexhaust pipes were processed with an oxyhydrogen burner and a plasma torch, respectively, and then about 100/15
Ten 150W double-ended compact lamps each subjected to a vacuum furnace treatment at 0 ° C were manufactured. FIG. 5 shows a completed drawing of this lamp. When these lamps were subjected to a life test, changes in the luminous flux maintenance factor and the re-ignition peak voltage were obtained in FIGS. 6 and 7.

From FIG. 6, the luminous flux maintenance factor was 85% for the oxyhydrogen burner at 2400 hours and 91% for the plasma torch. In the case of the oxyhydrogen burner, the re-ignition peak voltage rises to 150 V, and
The lights went out. On the other hand, in the case of the plasma torch, it was 40 V or less. As described above, a significant difference in characteristics due to the working burner appeared in the furnace treatment for 15 minutes. That is,
Compared with the processing by the oxyhydrogen burner, the processing by the plasma torch made it possible to obtain better characteristics than before with a shorter furnace processing time.

[0012]

EFFECTS OF THE INVENTION By using a plasma torch for processing quartz in the production of a metal halide lamp, OH groups mixed in quartz during processing can be minimized. Therefore, the characteristics can be remarkably improved even by the furnace treatment for a short time.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a method of manufacturing an unexhaust pipe of a metal halide lamp according to the present invention.

FIG. 2 is a view showing an unexhaust pipe processed by an oxyhydrogen burner.

[Fig. 3] 10 pieces of sample quartz processed by an oxyhydrogen burner
The figure which shows the processing time when performing a vacuum furnace process at 00 degreeC, and the relationship of OH group content.

[Fig. 4] 10 sample quartz processed with a plasma torch
The figure which shows the processing time when performing a vacuum furnace process at 00 degreeC, and the relationship of OH group content.

FIG. 5 is a diagram showing an embodiment of a metal halide lamp according to the present invention.

FIG. 6 is a characteristic diagram showing a change in luminous flux maintenance factor with the passage of lighting time.

FIG. 7 is a characteristic diagram showing changes in re-ignition peak voltage with the passage of lighting time.

[Explanation of symbols]

 1 Sealing part 2 Mold part 3 Tapered part 4 Main tube part 5 Quartz glass 6 White heat insulating film 7 White heat insulating film 8 Outer tube

Claims (4)

[Claims] 1. A method of manufacturing a metal halide lamp, characterized in that, in manufacturing a metal halide lamp, a plasma torch is used for processing a quartz arc tube or a quartz outer tube, and OH groups mixed in quartz during processing are reduced as much as possible. 2. The method for producing a metal halide lamp according to claim 1, wherein a high temperature vacuum furnace treatment is performed after processing the quartz arc tube or the quartz outer tube. 3. The method for producing a metal halide lamp according to claim 2, wherein the OH content in each part of the quartz arc tube or the quartz outer tube is reduced to 1 ppm or less by performing a high temperature vacuum furnace treatment. 4. The method of manufacturing a metal halide lamp according to claim 3, wherein the high temperature vacuum furnace treatment time is set to 15 minutes or less.