JP3605909B2 - Manufacturing method of metal halide lamp - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a manufacturing method applied to a manufacturing process of a metal halide lamp and minimizing OH groups mixed in quartz.
[0002]
[Prior art]
BACKGROUND ART In recent years, metal halide lamps have been used for many purposes, particularly where high efficiency and high color rendering properties are utilized. However, in the manufacture of metal halide lamps, oxyhydrogen burners conventionally used for quartz processing mix OH groups into the quartz during the manufacturing processing. This OH group is released as hydrogen when the lamp is turned on after completion of the lamp. The released hydrogen causes problems such as extinguishing at the start of the lamp, an increase in the starting voltage, and an abnormality in the halogen cycle, which adversely affects the lamp life characteristics such as blackening and devitrification of the arc tube. Due to this problem, it is said that it has a shorter life than a mercury lamp or a high-pressure sodium lamp.
[0003]
[Problems to be solved by the invention]
The present invention has been made in order to solve the above problems, and minimizes OH groups to be mixed into quartz during the manufacturing process, so as to extinguish the lamp at the time of starting, increase the starting voltage, blacken or devitrify the arc tube. It is intended to suppress and supply a long-life metal halide lamp.
[0004]
[Means for Solving the Problems]
The method for manufacturing a metal halide lamp according to the present invention is a method for manufacturing a metal halide lamp using a plasma torch for processing a quartz arc tube or a quartz outer tube, wherein a high-temperature vacuum furnace treatment is performed after the quartz arc tube or the quartz outer tube is machined. Thus, the OH content of each part of the quartz arc tube or the quartz outer tube is set to 1 ppm or less.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention uses a plasma torch instead of an oxyhydrogen burner for processing a quartz arc tube and a quartz outer tube used for a metal halide lamp. By not using oxyhydrogen gas for processing the quartz tube in this way, the OH group mixed into the quartz during processing becomes very small, and the lamp manufactured by the manufacturing method of the present invention can be extinguished when starting the lamp or start voltage can be reduced. , And blackening and devitrification of the arc tube are suppressed, and a long-life metal halide lamp can be supplied.
[0006]
【Example】
Hereinafter, details of the present invention will be described with reference to the illustrated embodiments. FIG. 1 is a view for explaining a method of manufacturing an unexhausted 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 an infrared transmission method. As a result, it was confirmed that the OH group content of the quartz tube was 1 ppm or less. The method for manufacturing the unexhausted pipe of the metal halide lamp includes a side pipe joining step (a) and a sealing step (b) as shown in FIG. First, the side tube process includes a drawing (taper) process (a-1) and a joining process (a-2). In this process, OH groups are mixed by the processing of the oxyhydrogen burner. Next, in the sealing step (b), OH groups are mixed by the processing of the oxyhydrogen burner.
[0007]
FIG. 2 shows a 4000 W non-evacuated pipe processed by the oxyhydrogen burner. The OH group content in the quartz was measured for the sealed portion 1, the molded portion 2, the tapered portion 3, and the main tube portion 4 of the unexhausted pipe using an infrared transmission method. When processed with an oxyhydrogen burner, the OH group content of each part of the unexhausted pipe was 13 ppm for the sealing part, 11 ppm for the molding part, 15 ppm for the tapered part, and 2.5 ppm for the main pipe part.
[0008]
Next, the 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. FIG. 3 shows the relationship between the processing time and the OH group content when the sample quartz was subjected to a vacuum furnace treatment at 1000 ° C. Even in the vacuum furnace treatment for 6 hours, the taper portion still has an OH group content of 8 ppm, and in order for each of the above portions to be in a state before processing (1 ppm), treatment for 32 hours or more was required.
[0009]
A similar test was performed by changing the processing burner to a plasma torch. The result is shown in FIG. By using a plasma torch, each of the above parts could be brought into a state before processing (1 ppm) in a vacuum furnace treatment for 15 minutes.
[0010]
On the basis of the results, each of the unexhausted pipes was processed with an oxyhydrogen burner and a plasma torch, and a vacuum furnace treatment at 1000 ° C. for about 15 minutes was performed to produce 10 lamps each having a 150W double-necked compact lamp. FIG. 5 shows a completed view of the 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 FIG. 6 and FIG.
[0011]
FIG. 6 shows that the luminous flux maintenance rate was 85% in the case of the oxyhydrogen burner at 2400 hours, and 91% in the case of the plasma torch. In the case of the oxyhydrogen burner, the re-ignition peak voltage increased to 150 V, and one lamp went out. On the other hand, in the case of the plasma torch, the voltage was 40 V or less. Thus, a significant difference in characteristics due to the processing burner appeared in the furnace treatment for 15 minutes. In other words, by performing processing using a plasma torch as compared with processing using an oxyhydrogen burner, it was possible to obtain more characteristics in a shorter furnace processing time.
[0012]
【The invention's effect】
By using a plasma torch for quartz processing in the manufacture of metal halide lamps, OH groups mixed into quartz during processing can be reduced as much as possible. Therefore, the characteristics can be remarkably improved even by a short furnace treatment.
[Brief description of the drawings]
FIG. 1 is a view for explaining a method of manufacturing an unexhausted pipe of a metal halide lamp according to the present invention. FIG. 2 is a view showing an unexhausted pipe processed by an oxyhydrogen burner. FIG. 3 is a sample processed by an oxyhydrogen burner. FIG. 4 is a graph showing the relationship between the processing time and the OH group content when quartz is subjected to a vacuum furnace treatment at 1000 ° C. FIG. 4 The treatment time when a quartz sample processed by a plasma torch is subjected to a vacuum furnace treatment at 1000 ° C. FIG. 5 is a diagram showing an example of a metal halide lamp according to the present invention. FIG. 6 is a characteristic diagram showing a change in a luminous flux retention rate with a lapse of lighting time. Characteristic diagram showing change of re-ignition peak voltage with time [Description of symbols]
DESCRIPTION OF SYMBOLS 1 Sealing part 2 Mold part 3 Taper part 4 Main pipe part 5 Quartz glass 6 White heat insulation film 7 White heat insulation film 8 Outer tube

Claims (1)

In a method for manufacturing a metal halide lamp using a plasma torch for processing a quartz arc tube or a quartz outer tube, a high-temperature vacuum furnace treatment is performed after the quartz arc tube or the quartz outer tube is processed, whereby the quartz arc tube or the quartz outer tube is processed. A method for producing a metal halide lamp, wherein the OH content of each part of the tube is 1 ppm or less.

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