JPH0721910A - Metal vapor electric discharge lamp and manufacture thereof - Google Patents

Abstract

PURPOSE:To carry out film formation at a low cost and simply by using a chemically stable rare earth oxide also having good heat resistance for a film for preventing its reaction with an emission substance. CONSTITUTION:Formation of a film on the inner surface of an emission tube is carried out in a following manner. AlCl3 placed in a carburetor 3 is heated to a temperature higher than a sublimation temperature and is gasified, and is guided into a heated reactor 6, along with an inert gas or a mixed gas of the inert gas and Cl2. The gas is reacted with an rare earth ion in a rare earth compound placed in the reactor 6 to form a complex compound in a phase condition, and is guided into an emission tube material 9 provided in an electric furnace 8 for forming film by the stream of the gas, and a rare earth chloride is reproduced on the inner surface of the emission tube material 9. After the abovementioned process is finished, vapor is guided into the emission tube material 9 along with air or the inert gas, to produce hydrolycal reaction. A film of rare earth oxide is thus formed on the inner surface of the emission tube material 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal vapor discharge lamp and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, a high pressure mercury lamp in which mercury and a rare gas are enclosed in an arc tube as a metal vapor discharge lamp is used in which one or several kinds of metal halides are combined as a light emitting substance in order to improve color rendering and luminous efficiency. A metal halide lamp that further encapsulates is used.

In the above-mentioned lamp, since the arc tube becomes hot during lighting, the enclosed luminous substance reacts with the arc tube, causing the arc tube to change color and devitrification due to crystallization of the arc tube material. There is a problem that the light transmittance of the arc tube is lowered or the strength of the arc tube is lowered, and the lamp life is shortened. Also, the metal of the metal halide reacts with the arc tube,
The halogen left by the disappearance causes non-lighting or extinguishing phenomenon due to an increase in the starting voltage or the lamp voltage, which also has a drawback of shortening the lamp life.

In order to solve these problems, there has been proposed a metal vapor discharge lamp in which the inner surface of the arc tube is coated. For example, one coated with fine particles of metal oxide or a mixture of several fine particles of metal oxide is coated (Japanese Patent Laid-Open No. Sho 4).
9-88375, JP-A-50-12877, JP-A-50-12878, JP-A-51-32.
In addition, it is difficult to form a dense metal oxide film having no defects when fine particles are used, and as a modification of the defect, an organic metal such as metal alcoholate is used. (See JP-A-50-12881 and JP-A-52-51776).
As a method for further improving the compactness, etc., a method using a CVD method using a metal chelate compound (Japanese Patent Application Laid-Open No. 3-238)
747).

[0005]

However, the above-mentioned C
With the VD method, a dense film can be formed, but the metal chelate compound used as the material is expensive, and since it is the CVD method, it is necessary to control the gas flow rate, etc. However, in the case of the plasma CVD method, a device such as a high frequency power source is further required, and thus the formation of the coating film inside the arc tube by this method has a drawback that it is very expensive.

The present invention has been made in view of the above drawbacks.
The purpose is to make the film formed on the inner surface of the arc tube to prevent the reaction between the arc tube and the luminescent material a chemically stable and heat resistant rare earth oxide, and to form the film at a low cost. Another object is to provide a method for forming a film easily.

[0007]

In order to solve the above problems, the present invention provides an inner surface of an arc tube made of quartz glass, high silicate glass, translucent ceramics or single crystal ceramics.
In the manufacture of a metal vapor discharge lamp for forming a coating film made of a rare earth oxide, the film formation on the inner surface of the arc tube is performed by the steps including the following steps.

AlCl ₃ placed in the vaporizer is heated to a temperature equal to or higher than the sublimation temperature to be vaporized, and introduced into a heated reactor together with an inert gas or a mixed gas of an inert gas and Cl ₂ , and the inside of the reactor Reaction with rare earth ions in the rare earth compound placed in the chamber to generate a gas phase composite compound, which is guided by the gas flow into the arc tube material installed in the electric furnace for film formation, and the inner surface of the arc tube material The process of regenerating rare earth chlorides.

After the above steps, a step of introducing water vapor together with air or an inert gas into the arc tube material to cause a hydrolysis reaction to form a film of a rare earth oxide on the inner surface of the arc tube material.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view showing a film forming method on the inner surface of an arc tube according to the present invention. First, the structure will be described.

Material A (AlCl ₃ ) 1 is a vaporization electric furnace 2
It is placed in the vaporizer 3 provided inside. One end of the vaporizer 3 is a gas device (not shown) by a reaction gas introduction pipe 4.
And the other end is connected to the reactor 6 by a gas introduction pipe 5. Material B (rare earth compound) is contained in the reactor 6.
7 is installed, and the reactor 6 is installed in the reaction electric furnace 8. Regarding this rare earth compound,
The type of compound is not particularly limited.

The reactor 6 and the arc tube material (tube material) 9 for forming a coating film on the inner surface are connected via a bulb 10, and the arc tube material 9 is placed in an electric furnace 11 for film formation. is set up. Further, a water vapor introducing pipe 13 connected to a water vapor generating device (not shown) via a hydrolysis valve 12 is provided between the valve 10 and the arc tube material 9.
Are connected.

The other end of the arc tube material 9 is connected to an AlCl ₃ collector 15 through a valve 14 and H through a valve 16.
It is connected to the Cl processing device 17. The other end of the AlCl ₃ recovery unit 15 may be provided with a Cl ₂ processing device (not shown) if necessary.
It is connected to the.

Next, the film forming process will be described. (Step 1) In Step 1, the valve 10 is open, the hydrolysis valve 12 is closed, the valve 14 is open, and the valve 16 is closed. The vaporizer 3 is heated by the vaporization electric furnace 2 to the sublimation temperature of the material A (AlCl ₃ ) 1 placed inside (Since the sublimation temperature of AlCl ₃ is 183 ° C., the temperature higher than that). If it is good, 200 ℃ ~ 50
0 ° C is desirable). In this state, AlCl ₃ vaporizes and A
The reactor ₆ is an inert gas supplied as the l ₂ Cl _{6 through the} reaction gas introduction pipe 4 or a mixed gas of the inert gas and the Cl ₂ gas (preferably a mixture of the inert gas and the Cl ₂ gas). Be guided inside. The reactor 6 is heated to 300 ° C. or higher by the reaction electric furnace 8. In the reactor 6, the rare earth ions in the material B (rare earth compound) 7 cause the following reaction.

1. C of rare earth ions M ³⁺ and Al ₂ Cl ₆
A portion of l reacts to form MCl _x .

In order to accelerate this reaction, the gas supplied through the reaction gas introducing pipe 4 is an inert gas and Cl.
A mixed gas of _two gases is preferable.

2. nMCl _x (s, l) + m / 2 Al ₂ Cl ₆
(g) → M _n Al _m Cl _{nx + 3m} (g) (where s, l, and g represent the states of substances such as solid, liquid, and gas, respectively) Complex compound M _n Al _m Cl obtained by this reaction
_{nx + 3m} is a substance having a high vapor pressure and exists as a gas at the temperature inside the reactor 6. Therefore, the reaction gas is introduced into the arc tube material 9 installed in the film forming electric furnace 11 by the flow of the reaction gas. The reaction of the above formula 2 is a reversible reaction, and the reaction of the following formula 3 occurs depending on the temperature of the arc tube material 9 (this temperature is set in the film forming electric furnace 11).

3. M _n Al _m Cl _{nx + 3m} (g) → nMCl
_x (s, l) + m / 2 Al ₂ Cl ₆ (g) The temperature at which this reaction occurs depends on the type of rare earth. By this reaction, MCl _x is regenerated on the inner surface of the arc tube material 9. Further, the regenerated Al ₂ Cl ₆ is guided to the AlCl ₃ recovery unit 15 by the flow of the reaction gas. By setting the temperature of the collector 15 to be equal to or lower than the sublimation temperature of AlCl ₃ (for example, room temperature), the gaseous Al ₂ in the reaction gas
Cl ₆ returns to solid AlCl ₃ and is recovered. Further, when the Cl ₂ gas remaining in the reaction gas, Cl ₂
Since gas is toxic, it may be introduced into a Cl ₂ gas treatment device or the like for treatment as necessary.

(Step 2) After step 1, the valve 10 is closed, the valve 14 is closed, and the valve 16 is opened. Next, the hydrolysis valve 12 is opened to introduce water vapor into the arc tube material 9 together with air or an inert gas.
At this time, the temperature of the film-forming electric furnace 11 is preferably set high within a range in which the rare earth chloride MCl _x adhering to the inner surface of the arc tube material 9 does not sublime or evaporate (this temperature also depends on the rare earth metal MCl _x ). It depends on the type). In this state, the following four hydrolysis reactions occur.

4. MCl ₃ + 3H ₂ O → M (OH) ₃ +
3HCl (Note that the above formula and the following formulas 5 and 6 are 3
In addition, an example of a valent rare earth is shown) Further, when this reaction is occurring, since heating is also performed at the same time, the reaction of the following equation 5 also occurs, and a rare earth chloride film is formed on the inner surface of the arc tube material 9. To be done.

5.2M (OH) ₃ → M ₂ O ₃ + 3H ₂ O Apparently, the reaction of the following 6 equations is obtained by combining 4 equations and 5 equations.

6.2MCl ₃ + 3H ₂ O → M ₂ O ₃ +6
Since the HCl arc tube material 9 is in a heated state, the generated HC
1 and unreacted water vapor are introduced into the HCl processing apparatus 17 together with the air and the flow of the inert gas which have been sent in at the same time.

As can be seen from the equations (1) to (6), the method of forming the film of the rare earth oxide is not particularly limited, and the kind of the rare earth compound used as the material to be placed in the reactor 6 may be any kind.

Next, an example of forming Y ₂ O ₃ as a rare earth oxide coating on the inner surface of the arc tube will be described.

In the above (step 1), while the mixed gas of nitrogen and Cl ₂ gas as the reactive gas was flowed at a flow rate of 50 cc / min at 5: 1, the temperature of the vaporization electric furnace 2 was set to 200 ° C. and the reaction electric furnace was set to 200 ° C. Film formation was performed at a temperature of 8 or more at 1000 ° C. and a temperature of the film forming electric furnace 11 at 700 to 900 ° C. for 720 minutes. A compound containing Y (yttrium) as a material B (rare earth compound) 7 was placed in the reactor 6.

In the above (Step 2), the temperature of the electric furnace 8 for reaction was set to 500 to 900 ° C. while heating the steam with air at a flow rate of 50 cc / min, and heating was performed for 360 minutes.

The arc tube material 9 having the Y ₂ O ₃ film formed on the inner surface in the above process was taken out and cut into a predetermined length, and then electrodes were sealed at both ends to form an arc tube. After evacuating the inside of this arc tube, 9 mg of DyI ₃ and NdI were used as an encapsulating material.
₃ 5 mg, CsI 6 mg, mercury 20 mg, Ar gas 3
An input 250W type metal halide lamp with 0 Torr was created and lit with a 250W ballast. Also,
As a comparative example, a metal halide lamp having the same filling material and the same shape, in which the Y ₂ O ₃ film was not formed on the inner surface of the arc tube, was prepared and lit with a 250 W ballast.

As a result of lighting for 6000 hours, the luminous flux maintenance factor was 41% in the lamp in which the Y ₂ O ₃ film was not formed on the inner surface of the arc tube. However, the luminous flux maintenance factor of the lamp according to this example in which the Y ₂ O ₃ film was formed on the inner surface of the arc tube was 80%. From this result, it is understood that the life of the lamp is significantly improved by forming the Y ₂ O ₃ film on the inner surface of the arc tube.

Although the above-mentioned embodiment is a metal halide lamp having an electrode, it goes without saying that the present invention is also applied to an electrodeless HID lamp which has been recently researched and developed.

[0030]

According to the manufacturing method of the present invention, the coating film formed on the inner surface of the arc tube in order to prevent the reaction between the arc tube and the luminescent material is a rare earth oxide that is chemically stable and has good heat resistance. In addition, the coating can be formed at a lower cost and more easily than the conventional method. Further, the rare earth compound as a material is not particularly limited, and any compound may be used, and at the same time, AlCl ₃ as a material is also inexpensive, so that the manufacturing cost can be reduced.

Further, as described above, since the coating film on the inner surface of the arc tube can be made of a rare earth oxide which is chemically stable and has a good heat resistance, it is possible to provide a metal vapor discharge lamp having a good life characteristic. it can.

[Brief description of drawings]

FIG. 1 is a schematic view showing a film forming method on an inner surface of an arc tube according to the present invention.

[Explanation of symbols]

1 Material A (AlCl ₃ ) 2 Vaporization Electric Furnace 3 Vaporizer 4 Reaction Gas Introducing Pipe 5 Introducing Pipe 6 Reactor 7 Material B (Rare Earth Compound) 8 Reaction Electric Furnace 9 Arc Tube Material 10 Valve 11 Film Forming Electric Furnace 12 Hydrolysis Valve 13 Steam Inlet Pipe 14 Valve 15 AlCl ₃ Recovery Device 16 Valve 16 17 HCl Treatment Device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Seisuke Wada 1048 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works Co., Ltd.

Claims (2)

[Claims] 1. In the manufacture of a metal vapor discharge lamp in which a coating film made of a rare earth oxide is formed on the inner surface of an arc tube, a film is formed on the inner surface of the arc tube by a step including the following steps: Manufacturing method of vapor discharge lamp. AlCl ₃ placed in the vaporizer is heated to a temperature not lower than the sublimation temperature to be vaporized, and then inert gas or inert gas and Cl ₂ are added.
The gas is introduced into the reactor heated together with the mixed gas of, and is reacted with the rare earth ions in the rare earth compound placed in the reactor to form the gas phase composite compound, and the gas flow causes the electric furnace for film formation. Guide inside the arc tube material installed inside,
A step of regenerating rare earth chloride on the inner surface of the arc tube material. After the above steps, water vapor is introduced into the arc tube material together with air or an inert gas to cause a hydrolysis reaction,
A step of forming a film of a rare earth oxide on the inner surface of the arc tube material. 2. A metal vapor discharge lamp using an arc tube manufactured by the manufacturing method according to claim 1.