JP2003068203A - Discharge lamp and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a durable discharge lamp which can be manufactured safely by sealing rare gas into a sealing bulb at precise pressure without applying temporary pressure to the sealing bulb to prevent bursting. SOLUTION: An auxiliary tank 20 is branched from a tip tube connected to a sealing bulb 10 of a discharge lamp 1. Mercury or metal halide, etc., is temporarily stored in this auxiliary tank 20. An exhaust system 14 connected to the tip tube 13 exhausts contaminant evaporated from the sealing bulb 10 by heating it with a heating system 21 into vacuum exhaust air. In the next step, mercury, etc., is moved into the sealing bulb 10 from the auxiliary tank 20 and rare gas is injected from a gas cylinder 15 and condensed into solid or liquid with a cooling measures 19 such as liquid nitrogen and finally the tip tube 13 is cut off to complete the discharge lamp 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp and a method for manufacturing the same, and in particular, it outputs ultraviolet rays used for exposure in the manufacturing process of semiconductor devices (ICs), liquid crystal display panels (LCDs), printed circuit boards (PCBs) and the like. Discharge lamp and its manufacturing method.

[0002]

2. Description of the Related Art It is known that a discharge lamp that emits ultraviolet rays used in the above-described exposure process is manufactured by the following process. First, the sealing body (tubular body) is molded. Assemble the electrode parts (anode and cathode). The assembled electrode is fixed in place on the envelope. Seal the enclosure to make the inside airtight. Finally, a rare gas for causing the discharge lamp to emit light and a filling material such as mercury or a metal halide are sealed inside the sealing body at a predetermined pressure.

FIGS. 4A to 4C are explanatory views showing a main part of a conventional manufacturing process for manufacturing a discharge lamp. Figure 4
(A) shows the discharge lamp 1 in the initial stage of the manufacturing process. The envelope 10 of the discharge lamp 1 is provided with a pair of electrodes (anode and cathode) 11 and 12 facing each other, and a chip tube 13 communicating with the envelope 10 is provided near the electrode 11. An encapsulant such as mercury or a metal halide is encapsulated in the encapsulant 10 from the outside through the tip tube 13.

Next, as shown in FIG.
An exhaust device 14 and a gas cylinder 15 are connected to 13 via throttle valves (hereinafter simply referred to as valves) 16, 17 and 18. First, open valves 16 and 18,
The valve 17 is closed and the inside of the sealing body 10 is made into a substantially vacuum state by the exhaust device 14. Next, the valve 16 is closed, the valves 17 and 18 are opened, and the rare gas from the gas cylinder 15 is sealed.
Enclose inside. Further, as shown in FIG.
The noble gas sealed inside the sealing body 10 is solidified or liquefied by immersing 10 in liquid nitrogen 19, for example. Finally, the tip tube 13
Is cut off at the root thereof to seal mercury inside the sealing body 10 with mercury and a rare gas, whereby the discharge lamp 1 is completed.

FIG. 5 is a flow chart showing a conventional method of manufacturing the above-described discharge lamp 1. That is, an enclosure is enclosed in the discharge lamp (enclosure) 10 (step S1). Envelope 10
Is connected to the exhaust device 14 (step S2). The inside of the envelope 10 is evacuated by the exhaust device 14 (step S3). (Here, since an enclosure such as mercury is enclosed inside the envelope 10, it is impossible to heat the envelope 10 to remove dirt at this stage (step S4).) From the gas cylinder 15 The rare gas is sealed inside the sealing body 10 (step S5). Further, the enclosed material inside the envelope 10 is solidified with liquid nitrogen or helium (step S6). Finally, insert the tip tube 13 into the envelope 10.
(Step S7).

[0006]

However, in the above-described conventional manufacturing process, the process of enclosing the noble gas, mercury, or the like is the final stage of the manufacturing process of the discharge tube 1. The dirt and the impure gas adsorbed on the getter are accumulated inside the sealing body 10. In addition, the interior of the envelope 10 of the discharge lamp 1 is temporarily opened to the atmosphere when an enclosure such as mercury or metal halide is enclosed. Therefore, impurities are mixed into the inside of the envelope 10. As a result, it has been difficult to extend the life of the discharge tube 1 manufactured by the conventional method.

When the rare gas is sealed in the envelope 10 of the discharge lamp 1 at atmospheric pressure or higher, the tip tube 13 is connected to the exhaust device 14 to make the inside of the envelope 10 into a vacuum state, and then the rare gas is discharged. Is sealed at atmospheric pressure or higher, the valve in the exhaust passage is closed while the inside of the sealing body 10 is kept at atmospheric pressure or higher, and the exhaust pipe portion on the exhaust device 14 side is disconnected from this valve. And the envelope 10
For example, it is necessary to immerse the gas in liquid helium to solidify or liquefy the rare gas inside the sealing body 10 to separate the chip tube 13 and seal the sealing body 10 with mercury or a rare gas. However, since this requires a temporary pressurization, there is a risk of the envelope 10 rupturing, and there is a problem in work safety. Further, since the valve in the exhaust path has a structure capable of obtaining its function in a high vacuum state, the airtight reliability is poor with respect to the pressurized state, and leakage (leakage) from the valve occurs, so that the desired value can be obtained exactly. There was a problem that the rare gas could not be filled by pressure.

The present invention has been conceived in order to solve the above-mentioned problems of the prior art, and it removes stains accumulated in the discharge lamp envelope from the start of manufacturing to remove mercury and metal halides. It is an object of the present invention to provide a long-life discharge lamp by preventing impurities from being mixed in without enclosing the inside of the sealed body to the atmosphere when sealing the sealed body in the sealed body. Furthermore, in the process of sealing the rare gas at atmospheric pressure or higher in the sealed body, it is not necessary to pressurize the sealed body even temporarily, and there is no risk of the sealed body being ruptured, and the work can be performed safely. It is an object of the present invention to provide a method of manufacturing a discharge tube capable of enclosing a rare gas at a desired pressure.

[0009]

The discharge lamp of the present invention has a tip tube connected to a sealing body provided with a pair of electrodes, and an exhaust device and a gas cylinder of a rare gas or the like connected thereto so that the discharge lamp is evacuated during manufacture. A rare gas is sealed, and an auxiliary tank is branched and connected to the tip tube to temporarily store the sealed material such as mercury sealed in the sealing body.

The method of manufacturing a discharge lamp according to the present invention is a method of manufacturing a discharge lamp in which a sealed body of the discharge lamp is filled with a filling material through a chip tube that can be separated, and an auxiliary tank is connected to the chip tube. Then, after once enclosing the enclosure in the auxiliary tank, the enclosure is encapsulated in the enclosure from the auxiliary tank through the tip tube, and then the tip tube and the auxiliary tank are separated from the enclosure. According to a preferred embodiment of the present invention, an exhaust device and a gas cylinder are connected to the tip tube, and the enclosure and the auxiliary tank are evacuated before moving the enclosure to the enclosure, and the rare gas is enclosed from the gas cylinder. The filling pressure of the rare gas filled in the envelope and the auxiliary tank is less than atmospheric pressure. Before separating the tip tube from the sealing body, it is cooled to solidify or liquefy the rare gas. The transfer of the enclosed material stored in the auxiliary tank to the sealed body is performed after the heat treatment. The heat treatment is performed simultaneously with the exhaust treatment.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration and operation of a preferred embodiment of a discharge lamp and a method for manufacturing the same according to the present invention will be described in detail below with reference to the accompanying drawings.

1 (A) to 1 (E) are process diagrams showing main manufacturing steps of a preferred embodiment of the method for manufacturing a discharge lamp according to the present invention. It should be noted that, for convenience of explanation, the same reference numerals are used for the components corresponding to the components of the conventional art described above.

As shown in FIG. 1 (A), in the discharge lamp of the present invention, not only the tip tube 13 but also the tip tube 13 of the envelope 10 constituting the discharge lamp 1 is branched in the middle of the tip tube 13 and the auxiliary tank 20 is provided.
Are connected, and the sealing body 10 and the auxiliary tank 20 communicate with each other through the tip tube 13. Further, an exhaust device 14 and a gas cylinder 15 can be connected to the tip tube 13 as described later. In the envelope 10, a pair of electrodes (anode and cathode) 11 and 12 are arranged in advance so as to face each other at a predetermined interval. The envelope 10 is made of, for example, quartz glass having an outer diameter of about 70 mm. On the other hand, the tip tube 13 has, for example, an outer diameter of about 1
It is made of 0 mm quartz glass. The materials of the envelope 10 and the tip tube 13 may be made of other materials depending on the application. Mercury or metal halide is sealed from the tip tube 13 into the auxiliary tank 20 and temporarily stored.

Next, as shown in FIG. 1B, a tip tube
An exhaust device 14 and a gas cylinder 15 are connected to one end (upper end) of 13 via a valve 18, and further via valves 16 and 17, respectively. First, the valves 16 and 18 are opened, the valve 17 is closed, and the sealing body 10 and the auxiliary tank 20 are evacuated. At the same time, the sealing body 10 is heated by the heating device 21 as shown in FIG. By this heat treatment, the envelope 10
The contamination accumulated inside and the contamination inside the sealing body 10 due to opening to the atmosphere when sealing the enclosed material in the auxiliary tank 20 are removed. Even if the sealing body 10 is heated by the heating device 21, the enclosed material stored in the auxiliary tank 20 does not evaporate or scatter.

Next, the heating of the envelope 10 by the heating device 21 is stopped and the envelope 10 is cooled to room temperature. Then, when the above-described vacuum exhaust is completed, the valve 16 is closed and the valve is closed.
Opening 17 and 18, the rare gas is sealed inside the sealing body 10.
The filling pressure P0 of the rare gas is the filling pressure P1 of the rare gas in the discharge lamp envelope 10 when completed, the volume V1 of the auxiliary tank 20,
It is calculated from the volume V2 of the envelope 10 and the volume V3 of the tip tube 13. The volume V of the auxiliary tank 20 used
1 is the volume V2 of the envelope 10 and the volume V3 of the tip tube 13,
Considering the rare gas filling pressure P1 in the discharge lamp envelope 10 when completed, the rare gas filling pressure P0 is selected to be less than the atmospheric pressure.

Next, as shown in FIG. 1C, the tip tube 1
It is separated from the exhaust device 14 at the position a in FIG. 3 and is sealed as shown in FIG. This disconnection is
For example, it is sealed by melting with an oxyhydrogen burner.
After that, as shown in FIG. 1 (E), the sealed material stored in the auxiliary tank 20 is sealed in the sealing body 10 by a method such as rolling, and the sealing body 10 is immersed in liquid nitrogen or liquid helium to seal the sealing body. 10 The noble gas inside is solidified or liquefied. Finally, when the noble gas existing in the auxiliary tank 20 and the envelope 10 is solidified or liquefied to reach an equilibrium state, the tip tube
Separate the envelope 10 and the auxiliary tank 20 near the position b of 13. When the envelope 10 of the discharge lamp 1 is restored to room temperature, the enclosure of the enclosure and the enclosure of the rare gas having a predetermined enclosure pressure are completed.

As described above, when the rare gas is filled into the sealing body 10 from the gas cylinder 15 after the exhausting by the exhaust device 14,
Since the pressure is not applied even temporarily, it is possible to eliminate the risk of the envelope 10 bursting and ensure the stability of the work. Also,
No rare gas leaks from the valve of the tip tube 13, and the rare gas can be accurately filled at a desired pressure.

FIG. 2 is a flow chart showing the manufacturing process of the preferred embodiment of the above-described discharge lamp according to the present invention.
First, an encapsulant is enclosed in the auxiliary tank 20 connected to the envelope 10 of the discharge lamp via the tip tube 13 (step A1).
Next, the exhaust device 14 is connected to one end of the tip tube 13 (step A2), and the inside of the sealing body 10 and the auxiliary tank 20 is evacuated (step A3). The envelope 10 is put in the heating device 21 to remove contamination (step A4). The envelope 10 is taken out from the heating device 21 (step A5), and the rare gas is enclosed in the envelope 10 and the auxiliary tank 20 from the gas cylinder 15 (step A6).
Next, the envelope 10 and the auxiliary tank 20 are separated from the exhaust device 14 (step A7). Enclose the enclosure in the auxiliary tank 20
10 (step A8), and the enclosure 10 is solidified with liquid nitrogen or helium (step A8).
9). Finally, the tip tube 13 is separated from the sealing body 10 to complete the discharge lamp 1 (step A10).

Next, by heating the envelope 10 of the discharge lamp 1, contamination and accumulated substances accumulated from the start of the manufacturing process are sealed in the auxiliary tank 20, and the envelope 10 is opened to the atmosphere.
With reference to FIG. 3, the result of the life test in the case where the contamination in the interior is removed in the step of filling the discharge lamp 1 with mercury and a rare gas, which is the final stage of the manufacturing process of the discharge lamp 1, will be described with reference to FIG. In this experiment, two types of short arc type were used, one in which the entire sealing body of the discharge lamp was heat-treated and the other in which the heating treatment was not performed in the step of filling mercury and rare gas into the sealing body 10 of the discharge lamp 1. Discharge lamps were manufactured and the life of the discharge lamps was compared. In the short arc type discharge lamp for this comparison test, the envelope 10
Is a quartz tube having an outer diameter of 70 mm and an internal volume V2 of 170 cc. The cathode 12 is made of tungsten containing about 2% by weight of thorium, has an outer diameter of about 10 mm, and the tip end facing the anode 11 is formed at an acute angle, and the distance between the anode 11 and this tip end is about 4.5 mm. Is. In addition, the auxiliary tank 20
The internal volume V1 was 508 cc, and about 30 mg / cc of mercury was enclosed and stored. Also, the inner volume of the tip tube 13 is V3
Is 2 cc.

An exhaust device 14 is connected to one end of the tip tube 13,
Encapsulation of mercury and rare gas into the envelope 10 is started. Envelope 10
After confirming that the degree of vacuum inside is 0.1 Pa or less, heat treatment is performed during evacuation at a high temperature of about 1100 ° C. for about 13 hours. After cooling the envelope 10 to room temperature, the exhaust device 14 is stopped, and at the same time, the envelope 10 and the auxiliary tank 20 are filled with 48 kPa of argon gas from the gas cylinder 15 and the tip tube 13 is sealed and cut at the position a. After that, the mercury stored in the auxiliary tank 20 is moved into the sealing body 10. Then, the sealing body 10 is dipped in a liquid helium tank to be sufficiently cooled, and the inside of the sealing body 10 is liquefied including the argon gas sealed in the auxiliary tank 20. At this time, the auxiliary tank 20
Use a Tesler coil to visually confirm that the internal pressure has been sufficiently reduced in a glow discharge state.
Is cut off at position b. By returning the envelope 10 to room temperature, 190 kPa of argon gas was enclosed in the envelope 10.

The short arc type discharge lamp thus manufactured was lit with a constant input power of 3000W. In the result of the life test shown in FIG. 3, A shows the illuminance characteristic of the discharge lamp according to the present invention which was subjected to the heat treatment in the step of filling mercury and rare gas, and B shows the illuminance characteristic of the discharge lamp which was not subjected to the heat treatment. Show. As is clear from FIG. 3, the heat treatment improves the illuminance maintenance rate by about 10%. This is because, in the step of filling mercury and rare gas into the sealing body 10, the entire sealing body 10 is heat-treated while the inside of the sealing body is evacuated to vacuum.
This is because the contaminants adhering to the inside of 10 are efficiently exhausted to the outside of the sealing body 10. As a result, the ultimate vacuum is improved, impurities such as oxygen and water remaining in the sealing body 10 are almost completely removed, and electrode oxidation or the like is prevented during the lighting of the discharge lamp 1, so that the life can be extended.

The configuration and operation of the preferred embodiment of the discharge lamp and the manufacturing method thereof according to the present invention have been described above in detail. However, this embodiment is merely an example of the present invention,
It does not limit the present invention in any way. For example, the mercury and the argon gas sealed in the sealing body 10 may be other sealed substances.

[0023]

As can be understood from the above description, the discharge lamp and the method for manufacturing the same according to the present invention can bring about the following remarkable practical effects. That is, an auxiliary tank is provided separately from the discharge tube sealing body via the tip tube, and mercury or the like is stored until it is transferred to the sealing body. It also enables the filling of rare gas and extends the life of the discharge lamp.

Further, when the rare gas at atmospheric pressure or higher is filled in the sealed body, the sealed body of the discharge lamp is not temporarily pressurized, so that the risk of the sealed body of the discharge lamp exploding can be eliminated. Work safety can be secured. Furthermore, since the discharge lamp is not pressurized even temporarily, no leak occurs from the bulb connected to the tip tube, and it is possible to accurately fill the rare gas at the desired pressure in the discharge lamp enclosure. is there.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a preferred embodiment of a method for manufacturing a discharge lamp according to the present invention.

FIG. 2 is a flowchart showing a preferred embodiment of a method for manufacturing a discharge lamp according to the present invention.

FIG. 3 is a characteristic curve diagram showing a result of life comparison between a discharge lamp heat-treated by a manufacturing method according to the present invention and a discharge lamp not heat-treated.

FIG. 4 is an explanatory view showing a method of manufacturing a conventional discharge lamp.

FIG. 5 is a flowchart showing a manufacturing process of a conventional discharge lamp.

[Explanation of symbols]

1 discharge lamp 10 envelope 11, 12 electrodes 13 tip tube 14 Exhaust device 15 gas cylinder 16-18 valves 19 Cooling device (liquid nitrogen) 20 Auxiliary tank 21 heating device

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Izumi Serizawa             4896 Tamagawa, Chino City, Nagano Prefecture             Ku Factory Suwa Factory (72) Inventor Akiyoshi Fujimori             4896 Tamagawa, Chino City, Nagano Prefecture             Ku Factory Suwa Factory F-term (reference) 5C012 PP01 PP08

Claims (7)

[Claims] 1. A discharge lamp in which a tip tube is connected to a sealed body provided with a pair of electrodes, and which is connected to an exhaust device and a gas cylinder of a rare gas to evacuate and fill the rare gas during manufacturing. A discharge lamp, characterized in that an auxiliary tank is branched and connected to a tip tube to temporarily store an enclosure such as mercury enclosed in the enclosure. 2. A method of manufacturing a discharge lamp in which an enclosure is sealed in a casing of a discharge lamp via a separable tip tube, wherein an auxiliary tank is connected to the tip tube, and the enclosure is temporarily filled with the enclosure. After encapsulating, the encapsulant is encapsulated in the encapsulant from the auxiliary tank via the chip tube, and then the chip tube and the auxiliary tank are separated from the encapsulant. . 3. An exhaust device and a gas cylinder are connected to the tip tube, and the sealing body and the auxiliary tank are evacuated before moving the sealing material to the sealing body to seal a rare gas from the gas cylinder. The method according to claim 2, wherein the discharge lamp is manufactured. 4. The method of manufacturing a discharge lamp according to claim 2, wherein a filling pressure of the rare gas filled in the sealing body and the auxiliary tank is less than atmospheric pressure. 5. The manufacturing of a discharge lamp according to claim 2, wherein the noble gas is solidified or liquefied by cooling the sealing body before separating the tip tube from the sealing body. Method. 6. The method of manufacturing a discharge lamp according to claim 2, wherein the enclosed material stored in the auxiliary tank is moved to the envelope after the heat treatment. 7. The method of manufacturing a discharge lamp according to claim 6, wherein the heat treatment is performed simultaneously with the exhaust treatment.