JPH0855605A - Metal halide lamp - Google Patents

Abstract

PURPOSE:To prevent a metal halide lamp from failing to be lighted due to cracks in a sealed portion without deteriorating the life performance characteristics of the lamp. CONSTITUTION:A quartz light emitting tube 1 is provided with a light emitting portion 2 inside which mercury, metal halide, and rare gas are enclosed and a pair of electrodes 7 are set, and sealing portions 3 which are set at the end portions of the light emitting portion 2 and parts of electrode 7 and molybdenum foil 6 connected thereto are sealed in. When the percentage content of metal elements contained in the quartz of the sealing portion 3 is expressed as Is by weight ratio, and the percentage content of metal elements contained in the quartz of the light emitting portion 2 is expressed as Ir by weight ratio, a condition, Is>Ir is to be met.

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.

[0002]

2. Description of the Related Art In recent years, metal halide lamps have a wide range of use due to their high luminous efficiency, and are being used not only as light sources for outdoor use but also as indoor lighting for stores and the like. However, the metal halide lamp has a large variation in the life, that is, the time until it becomes a defect, as compared with an incandescent lamp or a fluorescent lamp. The cause of this defect is that the gap between the molybdenum foil sealed in the arc tube sealing part and the quartz in the sealing part grows during its life, and eventually cracks and is enclosed in the arc tube. Most of the gas leaks to the outside.

[0003]

Although quartz glass is generally used for the arc tube of a metal halide lamp,
Since impurities emitted from quartz glass have a great influence on the lamp characteristics, extremely high-purity quartz glass is used. In the arc tube sealing process, quartz glass is heated with a gas burner or the like to a work temperature at which the viscosity becomes appropriate, and then crushed and sealed. Even if managed, the finished state of the sealing portion tends to vary. For this reason, the durability of the molybdenum foil to the expansion and contraction of the sealed portion during the life of the lamp tends to vary depending on the lamp.As a result, depending on the lamp, cracks may occur in the sealed portion early and There was a problem that there were things that became points.

The present invention provides a metal halide lamp which is capable of suppressing variations among lamps and preventing early defects due to cracks in the sealing portion without deteriorating the travel characteristics of the metal halide lamp made of quartz. The purpose is to

[0005]

A metal halide lamp according to the present invention is a light emitting section in which mercury, a metal halide and a rare gas are enclosed, and which has a pair of electrodes, and
A quartz arc tube is provided which is connected to an end of the light emitting section and has a sealing section in which a part of the electrode and a metal foil connected to the electrode are sealed. When the content ratio of the metal element contained in is Is by weight ratio and the content ratio of the metal element contained in the quartz of the light emitting portion is Ir by weight ratio, I
The condition of s> Ir is satisfied.

[0006]

With this structure, variations in lamps are suppressed without degrading the luminous flux maintenance factor characteristics, and cracking of the sealing portion during the life is prevented.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a 35 W metal halide lamp which is an embodiment of the present invention.

In FIG. 1, a quartz arc tube 1 has a light emitting part 2 and sealing parts 3 connected to both ends of the light emitting part 2, and inside the light emitting part 2 having an inner diameter of 3 mm, ScI ₃ and NaI as mercury and metal halides, and argon as a starting gas are enclosed. A molybdenum foil 6 as a metal foil is sealed in the sealing portion 3. Molybdenum foil 6
The external lead rod 5 is connected to one end thereof and one end of the electrode 7 is connected to the other end thereof, and is sealed by the sealing portion 3.
The outer tube 4 is made of quartz, both ends of the outer tube 4 are sealed with a molybdenum foil 6 interposed therebetween, and a vacuum is kept between the arc tube 1 and the outer tube 4 to keep the arc tube 1 warm.

Next, as the arc tube material, quartz having two kinds of compositions shown in (Table 1) was prepared, and these two kinds of quartz were combined as shown in (Table 2) to obtain three kinds of lamps ( A), (A), and (C) were prototyped.

[0010]

[Table 1]

Incidentally, the quartz A uses a material mainly containing titanium as a metal element, and the quartz B uses a material mainly containing aluminum as a metal element.

A life test of 3000 hours was conducted by horizontally lighting 10 lamps of each of the above 3 kinds of lamps (Table 2) and the results are shown.

[0013]

[Table 2]

As is clear from (Table 2), in the lamp (A), that is, in the case where the light emitting portion and the sealing portion contain a large amount of metal elements contained in quartz, the luminous flux maintenance factor is low, but defects due to cracks occur. Absent. Further, in the lamp (a), that is, in the case where the light emitting portion and the sealing portion contain only a small amount of metal elements in quartz, defects are caused by cracks, but the luminous flux maintenance factor is good. Further, in the case of a lamp (c), that is, a metal element contained in quartz has a small number of light emitting portions and a large number of sealing portions, no defect due to cracking occurs, and the luminous flux maintenance factor is high, which is excellent. Results were obtained.

The coefficient of expansion of glass is increased by incorporating a metal element into the component of quartz glass. Therefore, the difference in expansion coefficient with the molybdenum foil used for sealing is reduced,
Increases strength over temperature cycles during life. Similarly, by adding a metal element, the temperature range of the viscosity suitable for the glass processing operation is expanded. Therefore, the finished state of the sealing is stable even if the heating conditions for the sealing work vary slightly. However, where the glass temperature rises during lamp operation such as in the upper part of the arc tube, the metal element becomes the nucleus of the reaction and the quartz glass is crystallized, which promotes devitrification of the arc tube. This causes deterioration of the luminous flux maintenance factor of the lamp. That is, in the quartz glass used for the arc tube of the metal halide lamp, the content of the metal element is preferably low in a portion where the temperature rises, such as the light emitting portion, and the content of the metal element is preferably high in the sealing portion.

As described above, the metal halide lamp of the present invention has a light emitting section 2 in which mercury, a metal halide and a rare gas are enclosed, and which has a pair of electrodes 7, and
A quartz arc tube 1 is provided which is continuously provided at an end of the light emitting section 2 and has a sealing section 3 in which a part of an electrode 7 and a metal foil 6 connected to the electrode are sealed. When the content ratio of the metal element contained in the quartz of No. 3 is Is by weight ratio and the content ratio of the metal element contained in the quartz of light emitting unit 2 is Ir by weight ratio,
By satisfying the condition of Is> Ir, it is possible to suppress variations in the finished state of the sealed portion between the lamps and prevent early defects due to cracks in the sealed portion without degrading the luminous flux maintenance factor. it can.

Although aluminum and titanium are used in this embodiment, the same effect as above can be obtained even if other metal elements are included in quartz.

[0018]

As described above, according to the present invention, variations in the finished state of the sealing portion between the lamps are suppressed without deteriorating the travel characteristics, and cracks do not occur in the sealing portion during the life. It is possible to provide a metal halide lamp.

[Brief description of drawings]

FIG. 1 is a front view of a metal halide lamp that is an embodiment of the present invention.

[Explanation of symbols]

 1 luminous tube 2 luminous part 3 sealing part 4 outer tube

Front page continued (72) Inventor Takeshi Nagano 1-1, Saiwaicho, Takatsuki City, Osaka Prefecture Matsushita Electronics Industrial Co., Ltd.

Claims (1)

[Claims] 1. A light emitting part having mercury, a metal halide and a rare gas enclosed therein and having a pair of electrodes, and a light emitting part connected to an end of the light emitting part, and a part of the electrode and the electrode. A quartz arc tube having a sealing portion in which a connected metal foil is sealed is provided, and the content ratio of the metal element contained in the quartz of the sealing portion is Is in the quartz of the light emitting portion. A metal halide lamp characterized by satisfying a condition of Is> Ir, where Ir is a weight ratio of a metal element contained in.