JP2003197151A - Metal halide lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal halide lamp capable of restraining occurrence of a crack in a fine tube part in starting. <P>SOLUTION: A proximal conductor 21 is electrically connected to a lead wire 20a having one end inserted into a one-side fine tube 18a. A ring 22 made of ceramics is fitted onto the other-side fine tube 18b. The proximal conductor 21 is disposed along the circumferential surface of an arc tube body 17, and the other end thereof is wound around the ring 22. Thereby, insulation capability between the other end of the proximal conductor 21 and the tube part 18b is enhanced by interlaying the ring 22 between them, so that discharge generated in the vicinity of the tube part 18b in starting can be restrained. <P>COPYRIGHT: (C)2003,JPO

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 in which an arc tube made of translucent ceramic is filled with a metal halide.

[0002]

2. Description of the Related Art This type of metal halide lamp is shown in FIG.
As shown in FIG.
The arc tube 2 is provided with a starter 3 for applying a pulse voltage and a getter 4, and a base 5 is fitted in the opening of the outer bulb 1. The arc tube 2 has a structure in which both ends of an arc tube body 6 made of translucent ceramic are tapered, and a pair of thin tube portions 7 are provided at both ends.
a and 7b are formed, and a pair of electrodes 8a,
8b is provided and is filled with a starting gas such as a rare gas and a metal halide. The pair of electrodes are lead wires 9a and 9b inserted in the pair of thin tube portions 7a and 7b, respectively.
Is electrically connected to the starter 3 via. And
By applying a pulse voltage from the starter 3 between the electrodes 8a and 8b, the rare gas causes a dielectric breakdown to start discharge, and the discharge raises the temperature in the arc tube 2. As a result, the metal halide is vaporized, light having an emission spectrum determined by the metal halide is emitted to the outside of the arc tube 2, and the metal halide lamp starts the lighting operation.

In order to start the lighting operation as described above, it is necessary to apply a high voltage between the pair of electrodes to such an extent that a discharge is generated between them. This means that the lighting operation of the metal halide lamp is not started until the voltage applied between the pair of electrodes 8a and 8b from the starter 3 becomes high to some extent. Therefore, there is an arc tube 2 provided with a proximity conductor (reference numeral 10 in FIG. 5) in order to easily perform the lighting operation even at a low voltage at the time of starting.
An example thereof is disclosed in Japanese Patent No. 3208087. According to this, the proximity conductor 10 is formed of, for example, a metal wire, and one end thereof is connected to the lead wire 9a inserted into one thin tube portion 7a, and the other end is connected to the other thin tube portion 7b.
It is wound around. With such a configuration, the discharge can be started by a relatively low pulse voltage at the time of starting at a short distance between the other end of the proximity conductor 10 and the side of the other thin tube portion 7b, and lighting at the time of starting. The operation can be facilitated.

[0004]

However, the thin tube portions 7a and 7b are formed of thin ceramics, and in the case where the discharge is started at a position close to the thin tube portion as in the above-described conventional structure, for example, There have been problems that the starting voltage becomes high due to variations in the purity of the rare gas in the arc tube and that the thin tube portion is cracked when the lighting operation is repeated.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a metal halide lamp capable of suppressing the occurrence of cracks in a thin tube portion at the time of starting.

[0006]

In order to achieve the above object, the metal halide lamp according to the invention of claim 1 is made of a translucent ceramic in which a metal halide is filled and a pair of electrodes are arranged. An arc tube including a main body of the arc tube and a pair of thin tube portions provided at both ends of the main body of the arc tube and having lead wires connected to the respective electrodes inserted therein, and electrically connected to one side of the electrode In the metal halide lamp having a close conductor arranged close to the other side, a ceramic ring is fitted to one thin tube portion, and the close conductor is arranged close to the outer peripheral surface of the arc tube body. It is characterized in that one end is fixed to the ring.

The invention according to claim 2 is characterized in that, in the metal halide lamp according to claim 1, the arc tube main body is formed so that the peripheral walls at both ends thereof are thicker than other portions.

[0008]

<Advantageous Effects and Effects of the Invention><Invention of Claim 1> According to the configuration of Claim 1, the proximity conductor is arranged close to the outer peripheral surface of the arc tube body, and one end of the proximity conductor is fitted to one thin tube portion. It is fixed to a ceramic ring that is worn. As a result, due to the insulating function of the ceramic ring, it is possible to prevent the discharge in the vicinity of the thin tube portion at the time of starting and suppress the generation of cracks in the thin tube portion. Further, since the other end of the proximity conductor is fixed to the ring, the proximity conductor does not wobble due to, for example, external vibration.

<Invention of Claim 2> According to the configuration of Claim 1, the discharge at the time of starting often occurs through the peripheral walls near both ends of the arc tube body. Therefore, according to the structure of the second aspect, the peripheral walls of both end portions of the arc tube body are formed thicker than the other portions. As a result, it is possible to more reliably prevent damage to the arc tube body due to discharge.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <First Embodiment> A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic sectional view of a metal halide lamp according to this embodiment. This is a structure in which an arc tube 13 is supported in a ceramic outer bulb 11 via a support frame 12 made of a metal rod, and a starter 14 for applying a pulse voltage to the arc tube 13 in the outer bulb 11. The getter 15 is also enclosed. A base 16 is fitted on the end of the outer ball 11. As shown in FIG. 2, the arc tube 13 is made of a translucent ceramic and has an arc tube main body 17 in the shape of a right cylinder having tapered both ends, and a disk-shaped end plate 23 at both ends. , A pair of thin tube parts 1 attached via 23
It is composed of 8a and 18b. Inside the arc tube 13, a pair of electrodes 19a and 19b are arranged and a starting gas such as a rare gas and a metal halide are filled.
Here, as shown in the figure, the arc tube main body 17 is formed so that the peripheral walls of both taper portions gradually become thicker toward the opening end side (configuration corresponding to claim 2).

A through hole is formed at the center of the end plates 23, 23, and the thin tube portions 18a, 1 made of ceramic are formed in the through hole.
8b is fixed in a penetrating state. Thin tube parts 18a, 18b
Lead wires 20a and 20b connected to electrodes 19a and 19b, respectively, and a ceramic sleeve 24 made of translucent alumina are hermetically fixed to the inside by a sealing glass 25. Each of the electrodes 19a and 19b is constructed by winding a coil around its tip and also winding a coil around its base end. The purpose of the coil on the tip side is to protect the electrode from the high temperature of the arc spot formed at the tip of the electrode when the lamp is lit. The purpose of the coil on the base end side is to let the heat of the tip of the electrode escape to the rear of the electrode and also to serve to position the ceramic sleeve 24.

From the starter 14 to the lead wire 20a,
When a pulse voltage is applied between the electrodes 19a and 19b via 20b, the rare gas causes dielectric breakdown to start discharge, and the discharge raises the temperature in the arc tube 13.
As a result, the metal halide is vaporized, light having an emission spectrum determined by the metal halide is emitted to the outside of the arc tube 13, and the metal halide lamp starts the lighting operation.

In the metal halide lamp of this embodiment as well, the proximity conductor 21 is attached to the arc tube 13 so that the lighting operation can be started at a low voltage at the time of starting. More specifically, as shown in FIG. 2, the proximity conductor 21 is formed of, for example, a metal wire, and one end thereof has one thin tube portion 18
It is electrically connected to the lead wire 20a inserted through a.
Here, in the present embodiment, a ceramic ring 22 is fitted to the other thin tube portion 18b, and the proximity conductor 21
Are arranged along the outer peripheral surface of the arc tube body 17, and the other end is wound around this ring 22.

As described above, the ceramic ring 22 is interposed between the other end of the adjacent conductor 21 and the thin tube portion 18b to enhance the insulating property between them, so that the discharge at the time of starting the thin tube portion 18b. It is possible to suppress the generation in the vicinity. Since the other end of the close conductor 21 is wound around the ring 22, the close conductor 21 is vibrated from the outside, for example.
Does not fluctuate in the outer bulb, and there is no fear of colliding with, for example, the arc tube body or the outer bulb to damage it.

Further, with such a structure, discharge at the time of starting often occurs on the end side of the arc tube body 17, that is, near the taper portion. However, as mentioned above,
In the arc tube body 17, the peripheral walls of both tapered portions are formed so as to gradually become thicker toward the opening end side. That is, the outer peripheral wall of the tapered portion of the arc tube body 17 is formed thicker than the other portions. Therefore, it is possible to more reliably prevent the occurrence of cracks in the arc tube body 17 due to the electric discharge at the time of starting.

The effects of the structure of this embodiment will be described below by taking specific test conditions as an example. In this test, the following 10 lamps having the configuration (hereinafter referred to as “conventional specification”) described in the section of the conventional description and 10 lamps having the configuration according to the present embodiment (hereinafter referred to as “invention specification”) were used. The test was conducted under the conditions. In both the conventional specification and the invention specification metal halide lamps, the arc tube body and the narrow tube have the same shape, and the inner diameters are 15 mm and 1.5 mm, respectively.
The outer diameters are 17 mm and 3.5 mm, respectively, and the longitudinal dimensions are 33 mm and 15 mm, respectively. Then, dysprosium iodide, thallium iodide, sodium iodide, mercury, and argon gas were enclosed in each arc tube. Further, each of the metal halide lamps is an L-shaped lamp in which a glow tube is installed inside the outer bulb 11, and has a pulse voltage of 2000V at starting and a rated power of 220W. As the ballast, a general-purpose mercury lamp for 250 W was used.

Then, for each of the 10 lamps, the blinking operation was repeated for 60 minutes for lighting time and 30 minutes for extinguishing time. FIG. 3 is a graph showing the relationship between the lighting cycle and the number of remaining lamps in this test. As shown in the figure, no abnormalities were found in all 10 of the lamps until the lighting cycle was 2000 times, but cracks occurred in the narrow tube part in the conventional specifications from around 2000 times. Is appearing. On the other hand, the invention specification is lighting cycle 5
The flashing operation was repeated normally without cracks in the narrow tube portion of any of the lamps over 000 times.

<Second Embodiment> FIG. 4 shows a second embodiment. The difference from the above-described embodiment lies in the installation method of the proximity conductor 31 and the ceramic ring 32, and other points are the same as in the above-described first embodiment. Therefore, the same reference numerals as those of the first embodiment are given, duplicated explanations are omitted, and only different points will be explained next.

As shown in FIG. 4, the proximity conductor 31 is also formed of a metal wire, and one end thereof is electrically connected to the lead wire 20b inserted through the other thin tube portion 18b on the starter 14 side. A ceramic ring 32 is fitted in the thin tube portion 18a on the tip side of the lamp, the proximity conductor 31 is arranged along the outer peripheral surface of the arc tube body 17, and the other end is fixed to the ring 32. .

With such a structure, at the time of starting, the thin tube portion 18
Although the discharge is started on the a side, the ceramic ring 32 is provided between the other end of the proximity conductor 31 and the thin tube portion 18b.
It is possible to suppress the occurrence of electric discharge at the time of start-up near the thin tube portion 18a by intervening to increase the insulation between them.

<Other Embodiments> The present invention is not limited to the above-described embodiments. For example, the embodiments described below are also included in the technical scope of the present invention.
Other than the following, various modifications can be made without departing from the scope of the invention. (1) In each of the above-described embodiments, the arc tube main body 17 is formed so that the peripheral walls of both taper portions gradually become thicker toward the tip side, but the invention is not limited to this. If the outer peripheral wall of the tapered portion is formed thicker than the other portions, the occurrence of cracks in the arc tube body 17 can be suppressed.

(2) In each of the above embodiments, the proximity conductor 2
1, 1 and 31 are arranged along the outer peripheral surface of the arc tube main body 17, but they do not necessarily have to be in contact with the outer peripheral surface as long as they are located close to the outer peripheral surface. In addition, the proximity conductors 21 and 3
A configuration in which 1 is spirally wound along the outer peripheral surface of the arc tube body 17 may be used.

(3) In the above embodiments, the rings 22,
Although 32 is a separate member from the thin tube portions 18a, 18b and the end plates 23, 23, the present invention is not limited to this, and may be integrally formed with the thin tube portions 18a, 18b or the end plates 23, 23. Further, a configuration in which these and the arc tube body 17 are integrally molded may be used.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a metal halide lamp according to a first embodiment of the present invention.

FIG. 2 is a sectional view of an arc tube.

FIG. 3 is a graph showing the relationship between the lighting cycle and the number of remaining lamps.

FIG. 4 is an enlarged sectional view of an arc tube portion according to a second embodiment of the present invention.

FIG. 5 is a schematic sectional view of a conventional metal halide lamp.

[Explanation of symbols]

13 ... Arc tube 17 ... Arc tube body 18a, 18b ... Thin tube section 19a, 19b ... Electrodes 20a, 20b ... Lead wire 21, 31 ... Proximity conductor 22, 32 ... Ring

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kenichi Hata             No. 1 Inobaba-cho, Nishinosho, Kichijoin, Minami-ku, Kyoto-shi               Within Japan Battery Co., Ltd. F-term (reference) 5C039 BA06                 5C043 AA14 CC03 DD03 DD11 EA01

Claims (2)

[Claims] 1. An arc tube body made of a translucent ceramic in which a metal halide is filled and a pair of electrodes are arranged, and lead wires provided at both ends of the arc tube body and connected to the respective electrodes. In a metal halide lamp including a light emitting tube configured to include a pair of thin tube portions respectively inserted, and a proximity conductor electrically connected to one side of the electrode and arranged in proximity to the other side. A metal ring, wherein a ceramic ring is fitted to one of the thin tube portions, the proximity conductor is disposed in proximity to the outer peripheral surface of the arc tube body, and one end thereof is fixed to the ring. lamp. 2. The metal halide lamp according to claim 1, wherein the arc tube body is formed such that the peripheral walls at both ends thereof are thicker than other portions.