JPH02123659A - Metal vapor discharge lamp - Google Patents

Abstract

PURPOSE:To prevent corrosion and strength deterioration by forming the second blocking body and exhaust pipe with a metal material less active to oxygen or nitrogen than the material of the first blocking body and exhaust pipe. CONSTITUTION:A light emitting tube 1 is formed with a translucent ceramic and has the first blocking body 4 and the first exhaust pipe 7. The exhaust pipe 7 exhausts the inside of an internal pipe filled with a metal vapor. The blocking body 4 holds the exhaust pipe 7 and is seal connected to the open end of the internal pipe 2. Furthermore, the light emitting tube 1 is placed inside an external pipe 9 formed with a translucent ceramic constituting an envelope 2. This envelope 2 has the second blocking body 14 and the second exhaust pipe 15. The blocking body 14 is seal connected to the open end of the external pipe 9 and the exhaust pipe 15 is fastened to the blocking body 14 for exhausting the inside of the external pipe 9. The blocking body 14 and the exhaust pipe 15 are formed with a metal material less active to oxygen or nitrogen than the material of the blocking body 4 and the exhaust pipe 7.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a metal vapor discharge lamp comprising an arc tube that emits light by discharging metal vapor and is arranged inside an envelope.

(Prior Art) A metal vapor discharge lamp is a HID lamp (HLghInten
They are also called city discharge lamps, and are further classified into mercury lamps, metal halide lamps, high-pressure sodium lamps, etc., depending on the type of metal.

Among these, those that can emit infrared light are
Recently, it has been widely used in various fields such as the drying process of automobile production lines, the drying process of semiconductor production lines, the drying process of printing ink, and even the food processing field.

FIG. 2 is a sectional view showing the structure of, for example, a high-pressure sodium lamp among such conventional metal vapor discharge lamps.

The metal vapor discharge lamp in FIG. 2 first includes an arc tube 1,
It is composed of an envelope 2 in which the arc tube 1 is disposed.

The arc tube 1 includes an inner tube 3 made of translucent ceramics (for example, translucent alumina ceramics) and having open ends on both sides, and a first closing body that closes the open ends of the inner tube 3. 4.

The first closing body 4 is made of niobium (Nb), tantalum (
It is made of Ta) or the like.

The first closing body 4 and the open end of the inner tube 3 are hermetically sealed together with a solder glass 6 while the inner space 5 of the inner tube 3 is filled with metal vapor such as sodium (Na). There is. This solder glass 6 is made of aluminum oxide (A120
3), Calcium oxide (Cab), Magnesium oxide (
The main component is MgO), etc., and is compression molded in advance into a ring shape.

A first exhaust pipe 7 is fixed and held inside the first closing body 4 by electron beam welding, and an electrode 8 is further attached to the first exhaust pipe 7. This first
The exhaust pipe 7 is made of niobium (Nb), which is the same material as the first closing body 4.
) or tantalum (Ta).

The arc tube 1 as described above is disposed inside an outer tube 9 constituting the envelope 2. The outer tube 9 is made of translucent ceramics (translucent alumina ceramics), which is the same material as the inner tube 3, and its open ends on both sides are closed by second closing bodies 10.

Similar to the first closure body 4, the second closure body 10 has an outer tube 9
Niobium (N
b) is made of metal such as tantalum (Ta). This second closure body 10 and the open end of the outer tube 9 are connected to the outer tube 9.
They are hermetically sealed together by solder glass 12 while the internal space 11 of the two is evacuated. This solder glass 12 is also made of aluminum oxide (A I 203
), calcium oxide (CaO), magnesium oxide (MgO), etc. as main components, and is compression-molded in advance into a ring shape.

One end of the second exhaust pipe 13 is fixed to the inside of the second closing body 10 by electron beam welding. The ends are fixed by electron beam welding. This second exhaust pipe 13 is also made of niobium (Nb), which is the same material as the second closing body 10.
Alternatively, it is made of metal such as tantalum (Ta).

Note that the second exhaust pipe 13 is used to exhaust the air in the internal space 11 to create a vacuum state;
After finishing its function as an exhaust pipe, it functions as a contact member for electrically contacting the electrode 8 with an external power supply circuit (not shown).

Next, a process for assembling the conventional mercury vapor discharge lamp constructed as described above will be explained.

First, the first exhaust pipe 7 to which the electrode 8 is attached is inserted into the first closing body 4, and the exhaust pipe 7 is fixed to the first closing body 4 by electron beam welding. Then, the first closing body 4 with the first exhaust pipe 7 and electrode 8 attached thereto is attached to the open end of the inner tube 3 via the ring-shaped solder glass 6. In this state, unlike the illustrated state, the further end portion of the tip 7a of the first exhaust pipe 7 extends outside the first closing body 4, and the inner space 5 and the vacuum pump and a sealed gas tank.

Next, the inner tube 3 with the first closure body 4, first exhaust pipe 7, etc. assembled on both sides is sent into a high frequency heating furnace and heated at a temperature of 1550° C. for about 5 minutes. As a result, the ring-shaped solder glass 6 is melted, and the open end of the inner tube 3 and the first closure body 4 are hermetically joined.

On the other hand, while the heating is being performed for 5 minutes, the internal space 5 is brought into a high vacuum state by being evacuated through the first exhaust pipe 7, and a predetermined amount of sodium, mercury, Also, xenon gas, etc., which functions as a starting gas, is sealed inside. Then, when the internal space 5 reaches a predetermined pressure, the first exhaust pipe 7 is sealed off as shown in the figure using a hydraulic cutter or the like.

After the arc tube 1 is assembled in this way, the exhaust pipe 13 is inserted inside the second closing body 10 and the distal end 1
3a, the second closing body 10 is fixed by electron beam welding (at this point, the second closing body 10 is fixed only on one side).

Then, the other end of the second exhaust pipe 13 is welded to the tip 7a of the first exhaust pipe 7 in a bent state.

In this state, the further end portion of the distal end portion 13a of the second exhaust pipe 13 extends outward from the second closure body 4, as in the case of the first exhaust pipe 7.

Then, in this way, the first exhaust pipe 13 is connected to the second exhaust pipe on both sides.
The arc tube 1 with the closure body 10 assembled on one side is inserted into the outer tube 9. and two second closure bodies 1
The second exhaust pipe 13 is inserted into the remaining part of the outer pipe 9 and fixed by electron beam welding, and the second closing body 10 on both sides is connected to the opening of the outer pipe 9 through a ring-shaped solder glass 12. Attach to the end.

Thereafter, the outer tube 9 with the arc tube 1 inserted therein and with the second closing body 10 attached on both sides is sent into a high frequency heating furnace and heated at a temperature of 1550° C. for about 5 minutes. As a result, as in the case of the solder glass 6, the ring-shaped solder glass 12 is melted, and the open end of the outer tube 9 and the second closure body 10 are hermetically joined.

On the other hand, while the heating is being performed for 5 minutes, the internal space 11 is brought into a high vacuum state by a vacuum pump via the second exhaust pipe 13. Then, when the degree of vacuum in the internal space 11 reaches a predetermined value, a hydraulic cutter or the like is used to cut the second
The exhaust pipe 13 is sealed off as shown.

(Problem to be Solved by the Invention) By the way, the first and second closure bodies 4 in the above conventional example.
10, Tsl, and second exhaust pipe 7.1311: Niobium (Nb) or tantalum (Ta) metal is used, and both are made of the same material.

This is because, after considering the coefficient of thermal expansion, corrosion resistance, ease of processing, etc., it was thought that it would be better to use the same material for both to prevent variations in quality.

However, metals such as niobium and tantalum have a property of being active with oxygen and nitrogen in a high-temperature atmosphere, making them susceptible to corrosion due to oxidation and nitridation. Therefore, it is necessary to melt and heat the solder glass 612 in a high-frequency heating furnace in a vacuum state. However, when the solder glass 12 is melted and heated, a small amount of oxygen or nitrogen is generated from the arc tube 1 inserted into the outer tube 9, which causes niobium, tantalum, etc. to be oxidized or nitrided.

Therefore, corrosion or strength deterioration occurs in the second closing body 10 and the second exhaust pipe 13, and cracks may occur due to the load of the arc tube 1 itself or due to impact during automobile transportation. In particular, the tip 13 of the second exhaust pipe 13
Cracks, peeling, etc. often occurred near a due to the pressure bonding and cutting during sealing.

In addition, when using the lighting after the product is completed, the second closing body 1
The temperature of the 0 and second exhaust pipes 13 increases mainly due to radiation and conduction from the arc tube 1, which is at a high temperature of about 800°C. Therefore, heat from the outside is also added, and the temperature near the second closing body 10 and the second exhaust pipe 13 increases to 25.
When the temperature rises above 0° C., since these are directly exposed to the atmosphere, they are oxidized or nitrided, resulting in corrosion and strength deterioration. This has resulted in the disadvantage that the usage environment, usage conditions, etc. are significantly restricted.

The present invention has been made in view of the above circumstances, and its purpose is to improve the quality of metal by preventing corrosion and strength deterioration, and to avoid restrictions on the use environment, etc. Our objective is to provide steam discharge lamps.

(Means for Solving the Problems) The present invention provides a second method for solving the problems described above.
The closure body and the second exhaust pipe are made of a metal material that is more inert to oxygen or nitrogen than the material forming the first closure body and the first exhaust pipe.

(effect) t? The temperature of the i2 closing body and the second exhaust pipe increases under the influence of the first closing body and the first exhaust pipe, which are at high temperatures, so that they tend to react with oxygen or nitrogen. Therefore, if a metal material that is more inert to oxygen or nitrogen is used for the second closing body and the second exhaust pipe, these members will not be oxidized or nitrided.

(Example) Hereinafter, an example of the present invention will be described based on FIG. 1. However, the explanation will be simplified as much as possible by assigning the same reference numerals to the same components as those in FIG. 2 and omitting redundant explanations.

In FIG. 1, numerals 14 and 15 are a second closing body and a second exhaust pipe, each made of a Ni-Fe alloy, and the composition of the Ni-Fe alloy is 42% nickel (Ni),
The proportion of iron (Fe) is 58%.

In this embodiment, the second closing body 14 and the second exhaust pipe 15 are made of a Ni-Fe alloy that is more inert to oxygen or nitrogen than niobium or tantalum. Other than this, the structure is the same as that of the conventional example shown in FIG.

Here, specific numerical values regarding the size, enclosed metal vapor, etc. in this example will be shown.

First, the inner diameter and length of the inner tube 3 are 25 mm and 25 mm, respectively.
m+++, and the inner diameter and length of the outer tube 9 are each 36
111% 300m+e. 1st. Second closure body 4
．． The thickness of both exhaust pipes 14 is 0.2 mm, and the inner diameters of the first and second exhaust pipes 7 and 13 are both 6 mm.

Then, in the interior space 5 of the arc tube 1, 2 parts of sodium are added.
200a+g of NaHg amalgam containing 0ωt% is enclosed, and 20g of xenon (Xe) as a starting gas is added.
Torr is enclosed, and then the first exhaust pipe 7 is sealed off while maintaining a pressure of about 400) cg/c-.

Next, the assembly process of this embodiment configured as described above will be briefly explained.

First, the arc tube 1 is assembled through the same process as in the conventional example, and the assembled arc tube 1 is sent into a high-frequency heating furnace in order to heat and melt the solder glass 6. And 1550
C. for about 5 minutes to bond the open end of the inner tube 3 and the first closing body 4, and to seal off the first exhaust pipe 7 and the first closing body 4.

Next, the arc tube 1 assembled in this way is inserted into the inner tube 9 of the envelope 2, and the solder glass 12 is attached to the open end of the outer tube 9 in the same manner as in the conventional example (FIG. 2). Second closure body 1
Install between 4 and 4. And like this, solder glass 1
2 is attached to the outer tube 9 into a high frequency heating furnace,
As in the case of the solder glass 6, it is heated at a temperature of 1550° C. for 5 minutes, and then the second exhaust pipe 15 is sealed off.

As described above, the second closing body 14 and the second exhaust pipe 15
is made of Ni-Fe alloy, so the solder glass 1
Even if oxygen or nitrogen is generated from the arc tube 1 inserted into the outer tube 9 when the gas tube 2 is melted and heated, the second closing body and the second exhaust pipe 15 will be oxidized or nitrided. There is no corrosion or strength deterioration.

Furthermore, even if the product is used as a light in an environment where the ambient temperature rises to 250°C or higher after completion, there will be no corrosion or strength deterioration, and the usage environment and usage conditions will be limited. There isn't.

In this example, Ni-Fe alloy is used as the metal material, but nickel, iron, etc. are abundant resources and can be obtained at low cost, so NL-Fe alloy is also used as niobium, tantalum, etc. It can be manufactured much more cheaply. As a result, it also contributes to reducing the cost of the metal vapor discharge lamp as a whole.

These effects are supported by the following tests conducted by the inventor of the present invention.

That is, 10 high-pressure sodium lamps with a rated output of 3KW were manufactured using the assembly process described above, and these were
A test was conducted in which the sample was vibrated for 60 minutes at a vibration frequency of 200 ORPM (corresponding to the shock during transportation by automobile). After that, the lighting was operated under the conditions of 3 hours on and 30 minutes off, 500H (time:), 100OH, 3000H.
.

The second closure body 14 is removed every 5000 hours. Second exhaust pipe 1
5 and the surrounding areas were visually inspected. As a result, no cracks, tears, etc. were observed in any part of these members.

Furthermore, when the inventor of the present invention calculated the price of one metal vapor discharge lamp according to this embodiment, it was found that the cost could be reduced by 30% or more compared to the conventional lamp.

The inventor of the present invention further conducted the above test by changing various conditions.

For example, (a) In the above example, the composition of the Ni-Fe alloy is Nt(
42%)-Fe (58%),
Others: N1 (45%) -Fe (55%), Ni
(50-52%) -Fe (50-48%) alloys were also tested.

(b) The type of metal vapor sealed in the arc tube and the sealing pressure were varied within the range used in general metal vapor discharge lamps.

(c) Within the range of general metal vapor discharge lamps, the shapes of the arc tube and envelope were changed, and the materials of the inner tube and outer tube were also changed.

And, for the above (a) to (c), almost the same good test results could be obtained.

〔Effect of the invention〕

As explained above, according to the present invention, the second blocking body and the second exhaust pipe are made of a material that is less resistant to oxygen or nitrogen than the material forming the first blocking body and the first exhaust pipe. Since it is made of a metal material with active properties, it is possible to prevent corrosion and strength deterioration of these parts, and as a result,
It is possible to improve the quality of metal vapor discharge lamps, and 1.
, the usage environment, etc. can be made unrestricted.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG. 2 is a sectional view showing a conventional example. 1... Arc tube, 2... Outer envelope, 3... Inner tube, 4...
...first closure body, 7...first exhaust pipe, 9...outer pipe, 14...second closure body, 15...second exhaust pipe.

Claims (1)

[Scope of Claims] A first exhaust pipe for evacuating the inside of the inner tube in which metal vapor is sealed, and an open end portion of the inner tube that holds the first exhaust pipe and in which the metal vapor is sealed. an arc tube having a first closing body that is hermetically sealed to the outer tube and closes the open end; A metal vapor discharge lamp comprising: a closure body, and an envelope having a second exhaust pipe fixed to the second closure body and evacuating the inside of the outer bulb, the second closure body and A metal vapor characterized in that the second exhaust pipe is formed of a metal material that is more inert to oxygen or nitrogen than the material forming the first closing body and the first exhaust pipe. discharge lamp.