JPH11329350A - Discharge lamp and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp having a long service life by preventing the degradation of the service life of the lamp attributable to quartz glass constituting the discharge lamp and its filler gas and also provide a method to manufacture the discharge lamp which prevents impurities relating to the service life of the lamp from being mixed in. SOLUTION: In this discharge lamp, when glow discharge is generated by supplying a current of 3 mA to an electrode 3 in a light emission part 1, the ratio of the maximum intensity of the emission spectrum of hydrogen, oxygen and their compound which are present in the light emitting part to the intensity of the main emission spectrum of a noble gas is 1/1000 or less, and the content of the hydroxyl group in the quartz glass of sealing parts 2a, 2b is 5 ppm or less by weight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a long-life discharge lamp and a method for manufacturing the same.

[0002]

2. Description of the Related Art At present, discharge lamps represented by high-pressure mercury lamps and metal halide lamps are used for various purposes, and are widely used as indispensable in social life. Recently, higher performance of discharge lamps has been expected to improve social life. In particular, from the standpoint of protecting the global environment, extending the life of a discharge lamp is one of the most promising. Therefore, many technologies for extending the life of the discharge lamp have been invented to date.

[0003] In general, a discharge lamp encloses a pair of electrodes in a glass tube, and a discharge space in which two electrodes face each other is:
An appropriate gas is filled to form a light emitting section. The light emitting portion is filled with mercury or a metal halide, and is used as a mercury lamp or a metal halide lamp. Usually, quartz glass such as quartz glass is used for glass, and tungsten is used for electrodes.

Japanese Patent Application Laid-Open No. 2-223131 discloses a double-end type high-pressure discharge lamp in which two portions of a quartz tube are heated to form two narrow portions, and a first formed first portion is formed.
The tungsten electrode is positioned in the first constricted part, the glass tube is heat-sealed, the filling gas and the luminescent substance are charged, the tube end is sealed, and then the second electrode is connected to the other Similarly, the glass tube is heat-sealed by disposing it in the second narrowed portion, and the space between the first and second sealed portions is used as a light emitting portion. In this conventional technique, the sealing of the electrode is heating by a conventional burner, and gas filling and tube end sealing are performed by holding a glass tube in a glow box in a high-clean atmosphere with a filling gas, and thereafter. The sealing of the second electrode is performed in the atmosphere.

One of the biggest factors affecting the life of a discharge lamp is H ₂ contained in its constituent material.
The presence of impurities such as O. For example, quartz glass of a discharge lamp, usually quartz glass contains OH groups, and during lamp operation, the OH groups in the glass are released into a discharge space and are heated at a high temperature (about 3000 K) by a tungsten electrode. Promotes evaporation of the discharge lamp and often causes blackening or devitrification of the arc tube at an early stage, thereby shortening the life of the discharge lamp.

A method for suppressing the influence of the OH group contained in the glass on the life and prolonging the life of the lamp is disclosed in, for example, JP-A-9-102277 and JP-A-9-10.
No. 2278. These prior art lamp manufacturing methods include (1) using a propane oxygen burner or a plasma torch instead of an oxyhydrogen burner as a heat source for heating the glass, and using an OH group mixed into the glass during the processing. (2) In order to further remove OH groups mixed during processing, after processing, the glass or lamp is heated to a high temperature in a vacuum and released as H ₂ O, and the OH group level in the glass is reduced. It consists of returning to the state before processing.

As an effect of this manufacturing method, it is described that in the case of a lamp processed with an oxygen-hydrogen burner, the luminous flux maintenance ratio after a lighting time of 2400 hours was improved from 85% to 91%.

Japanese Patent Application Laid-Open No. 220220/1990 discloses a method of manufacturing a discharge lamp in which high-temperature vacuum heat treatment is performed at 1200 ° C. for about 6 hours. In this manufacturing method, as shown in FIGS. 16A and 16B, an electrode assembly is inserted from one end of a quartz tube 201 formed with an arc tube portion 206 and opened at both ends. , A molybdenum sealing foil 209 and a molybdenum current supply 2
And 10. And the quartz tube 201
In the region of the sealing foil 209, it was heated to a temperature suitable for molding of about 2200 ° C. or more, and at the same time, argon Ar was supplied from the open end and passed through the tube 210. When the crushing temperature is reached, the crushing jaw 13 is pressed,
The sealing foil 20 is sealed to form the first sealing portion 14 (first electrode sealing step). In this manufacturing method, the quartz tube 201 in which the first electrode is sealed is subjected to high-temperature vacuum heat treatment at 1200 ° C. for about 6 hours.

[0009]

SUMMARY OF THE INVENTION Incidentally, Japanese Patent Application Laid-Open No.
In the lamp manufacturing methods disclosed in JP-A-102277 and JP-A-9-102278, no consideration is given to impurities contained in lamp constituent materials other than glass.

In particular, H ₂ O contained in a sealed gas or a luminescent substance
And the impurities of the adsorbed water on the glass surface will be present inside the arc tube immediately after the lamp is completed.
The lamp characteristics are adversely affected earlier than impurities emitted from the glass. For this reason, Japanese Patent Application Laid-Open No. 9-1022
The method of manufacturing a lamp disclosed in Japanese Patent Application Laid-Open No. 77-102278 or Japanese Patent Application Laid-Open No. 9-102278 has a problem that the deterioration of life at the beginning of lighting cannot be sufficiently suppressed.

The above-mentioned JP-A-9-102277, JP-A-9-102278 and JP-A-2-220.
No. 328 discloses a conventional lamp manufacturing method,
A method for reducing the OH group content in glass by high-temperature vacuum heat treatment is disclosed. Generally, when the glass is heated to a high temperature and acted on thermally, the components of the glass such as Si and O
OH groups that are combined with H ₂ gas and H ₂ gas or H ₂ gas
O gas).

Therefore, when the high-temperature heat treatment is performed, even if the OH group is apparently reduced, it is actually caused by H ₂ gas or H ₂ O
In some cases, impurities that merely change to a gas form and adversely affect the life characteristics of the lamp are not substantially removed.
In addition, H ₂ gas and H ₂ O gas are more easily diffused in glass than impurities (OH group) combined with Si or O.

[0013] Therefore, when the removal of these gas constituent atoms is insufficient, heat treatment is performed instead, whereby impurities released from the glass are increased, and there is a problem that the lamp life is accelerated.

Further, as shown in JP-A-2-220328, the electrode assembly (208, 209, 21) is heated by flowing argon Ar into a quartz tube 201 having open ends.
When 0) is sealed, small argon bubbles are likely to remain in the sealing foil 209, and there is a problem that the airtightness cannot be sufficiently maintained at the sealing portion 14. Furthermore, since both ends of the quartz tube 201 are open, the surrounding atmosphere is
Easily flows into the tube. For example, when the first electrode sealing step shown in FIGS. 16A and 16B is performed in an air atmosphere, air flows into the quartz tube 201 together with argon, which oxidizes and contaminates the electrode 8. There are also issues.

An object of the present invention is to provide a discharge lamp having a long life by preventing the life of the lamp from being shortened due to the glass constituting the lamp and the sealing gas. Another object of the present invention is to provide a method for manufacturing a discharge lamp in which contamination of impurities related to lamp life is prevented.

[0016]

DISCLOSURE OF THE INVENTION The discharge lamp of the present invention comprises:
A light-emitting portion made of quartz glass, a sealing portion in which an electrode assembly protruding from the light-emitting portion is sealed, and a rare gas hermetically filled in the light-emitting portion, wherein hydrogen, oxygen, and compounds thereof in the light-emitting portion And the content of OH groups present in the sealing part glass are both regulated to a certain amount or less, thereby delaying the blackening and devitrification of the light emitting part glass and increasing the lamp life. .

More specifically, the discharge lamp of the present invention does not substantially contain hydrogen, oxygen, or a compound thereof (for example, water) in the rare gas in the light emitting portion. While the lamp is in use, these gas components disperse the molten portion generated at the electrode tip and contaminate the inner wall of the arc tube. The present invention prevents these contaminations by regulating these gases.

In the present invention, whether or not these elements or compounds are substantially contained can be determined by emission spectroscopy based on the relative relationship with the rare gas. That is, the maximum intensity of the spectral spectrum of hydrogen, oxygen, and their compounds existing in the light emitting portion when a glow discharge is performed by supplying a current of 3 mA is 1/1 / the spectral intensity of main emission of the rare gas.
1000 or less.

Further, according to the present invention, the content of OH groups contained in the quartz glass forming the sealing portion is 5 ppm by weight.
It is as follows. This reduces the amount of oxygen, hydrogen and their compounds released from the sealing glass into the discharge gas during lamp use.

The present invention includes a method of manufacturing a lamp including a light emitting portion made of quartz glass, a sealing portion in which an electrode protruding from the light emitting portion is sealed, and a rare gas hermetically filled in the light emitting portion. . A method for manufacturing a discharge lamp for regulating the abundance of hydrogen, oxygen, and their compounds (ie, water) in the light emitting portion and the content of OH groups present in the sealing portion glass to a certain amount or less. Realize.

That is, by using a quartz glass tube containing an OH group having a weight ratio of 5 ppm or less, a light emitting portion is formed by heating.
Then, the straight tube portion was heated and softened by laser or plasma irradiation to seal the electrode, the electrode was sealed in the sealed portion adjacent to the light emitting portion, and then the water content was previously reduced in the glass tube. Inject noble gas. Irradiation of laser or plasma onto the glass tube does not substantially increase the content of OH groups in the electrode sealing portion, as compared with the conventional heating and melting using an oxygen-hydrogen flame, and reduces the water content in the rare gas. Also does not increase. Therefore, the occurrence of blackening and devitrification of the light emitting portion glass during use of the lamp is delayed, and the life of the lamp is increased.

More specifically, the method of manufacturing the discharge lamp having the above-described structure includes a light emitting part forming step of heating and softening a quartz glass tube containing an OH group having a weight ratio of 5 ppm or less to form a light emitting part of a predetermined shape. Then, the electrode assembly is inserted into the straight tube portion adjacent to the light emitting portion, and the straight tube portion is heated and softened to seal the electrode assembly. Or a dosing step of inserting a predetermined amount of a liquid luminescent substance, and a gas filling step of sealing a predetermined amount of a rare gas in the light-emitting portion and airtightly filling the light-emitting portion. A straight gas is heated and softened by laser or plasma irradiation in a sealing step to seal the electrodes.

In the gas filling step, the rare gas is treated with hydrogen, oxygen,
And passing through a means for removing those compounds and enclosing the inside of the arc tube. As the removing means, a method of cooling the rare gas to a low temperature and removing the contained water as a liquid is adopted.

In the step of forming the light emitting section, laser irradiation or plasma irradiation is performed when heating and softening the quartz glass tube, so that OH groups or dissolved H ₂ O in the glass are not increased and a predetermined shape of light is emitted. A part can be formed.

In the method of manufacturing a discharge lamp according to the present invention, in the step of sealing the first and second electrode assemblies in a sealing portion,
After reducing the pressure inside the tube and sealing the both ends of the glass tube containing the rare gas, the quartz tube is heated and softened and sealed, so that the content of OH groups in the sealed portion can be reduced, and oxidation and contamination of the electrode can be prevented. This is effective in preventing blackening and devitrification of the lamp inner surface during long-term lamp use.

In the method of the present invention, further, in the step of sealing the electrode assembly, the quartz tube can be heated and softened by laser or plasma irradiation and sealed, thereby increasing the OH group content in the glass at the sealed portion. The discharge lamp having a long life can be manufactured by preventing blackening and devitrification of the inner surface of the lamp during long-term lamp use.

According to the production method of the present invention, a vacuum heat treatment step for removing moisture adsorbed on the quartz glass surface is added,
And after the vacuum heat treatment step, the lamp can be completed in a dry rare gas or nitrogen gas atmosphere without the quartz glass surface being normally exposed to air.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION A discharge lamp according to the present invention has a light emitting portion made of quartz glass, a sealing portion also made of quartz glass adjacent to the light emitting portion for sealing a pair of electrodes, and a light emitting portion. And at least a hermetically filled rare gas. Such discharge lamps include double-ended lamps and single-ended lamps. The double end lamp has a pair of electrodes opposed to each other in a light emitting portion, and a discharge gap is provided between the tip portions, and is arranged substantially in a straight line. The base of the electrode is sealed and fixed to sealing portions extending on both sides of the light emitting portion. In a single-ended lamp, a pair of electrodes are arranged in parallel, and both bases are sealed in parallel in one sealing portion.

As an example of a lamp, as shown in FIG. 1A, a double-ended lamp generally has a generally tubular or partially spherical light-emitting portion and electrode sealing portions on both sides of the light-emitting portion made of quartz glass. An electrode assembly is sealed in each of the sealing portions, and the tip of the electrode projects into the light emitting portion, and the electrodes face each other with a discharge gap. Each electrode assembly includes a lead for connecting to an external power supply.

The lamp is formed from fused silica glass, and the electrode assembly includes electrodes, lead foils connected to the electrodes, and leads connected to the lead foils. Since the electrode protrudes into the light emitting portion and directly generates a discharge, a high melting point metal, particularly preferably tungsten is preferably used because of its high melting point. The lead foil provides flexibility to the electrode structure and reduces the application of external force to the sealed electrode, and a molybdenum foil with high workability is used. The lead is appropriately selected from high melting point metals, but preferably tungsten is used.

The discharge lamp has a light emitting portion filled with a rare gas and hermetically sealed. As the rare gas, argon, xenon, or the like is used. The discharge lamp may contain mercury or metal halide as a luminescent agent in order to increase the luminance of light emission and adjust the hue.

The discharge lamp of the present invention contains substantially no oxygen, hydrogen, or a compound thereof in the rare gas in the light emitting portion. These elements and their compounds are spectroscopically defined as follows. That is, the maximum intensity of the spectral spectrum of hydrogen, oxygen, and their compounds present in the light emitting portion when a glow discharge is performed by supplying a current of 3 mA to the electrode in the light emitting portion is the spectral intensity of the main emission of the rare gas. To 1/1000 or less.

At the same time, in the lamp of the present invention, the sealing quartz glass for sealing the electrode assembly has an OH group of not more than 5 ppm by weight.

According to the present invention, the content of oxygen, hydrogen and their compounds in the rare gas in the light emitting portion and the OH group content in the quartz glass in the sealing portion are simultaneously regulated as described above. Oxidation and melting and scattering at the tungsten electrode are prevented, and clouding and devitrification on the inner surface of the light emitting portion of quartz glass are reduced and delayed. The OH group in the sealing portion is also kept at a high temperature by using the lamp for a long time and migrates into the rare gas in the light emitting portion, causing oxidation and volatilization of the tungsten electrode.

Further, the quartz glass forming the light emitting section is:
It is preferable that the content of the OH group is 10 ppm or less by weight ratio, particularly, 5 ppm or less by weight ratio. Although the absolute amount of OH groups contained in the light emitting part is smaller than that of the sealed part, it is released in the form of H ₂ O inside the light emitting part during long-term use, so the OH group content should be reduced. preferable. Therefore, in consideration of the resistance of the light emitting unit to devitrification, the more preferable amount of the OH group contained in the glass of the light emitting unit 1 is approximately the same as the OH group contained in the glass of the sealing units 2a and 2b (greater than 0). ) 5 ppm or less is preferable. Discharge lamps having a similar configuration of OH groups are more easily produced and more economical than lamps having different configurations of OH groups contained in the glass of the light emitting portion and the sealing portion.

Further, in a so-called metal halide lamp in which a metal halide is added to the light emitting portion 1 of the discharge lamp, the smaller the amount of OH groups contained in the glass of the light emitting portion 1, the better the life characteristics. This is because the OH group contained in the glass promotes the reaction between the metal halide and the glass (the phenomenon of devitrification of the glass) and deteriorates the glass (light emitting portion 1) at an early stage.

In the present invention, the quartz glass forming the sealing portion preferably has a residual compressive stress in the vicinity of the interface with the electrode. Preferably, the residual compressive stress is at least 25 MPa.

In a so-called metal halide lamp in which a metal halide is added to the light emitting portion 1 of the discharge lamp, the compressive stress remaining near the electrode 3 works particularly advantageously. The compressive stress suppresses the intrusion of the metal halide into the vicinity of the interface between the electrode 3 and the glass having a low temperature, thereby preventing a decrease in the vapor pressure of the metal halide and thus improving the light emission characteristics.

In the present invention, the glass of the light emitting section includes:
Although residual tensile stress may be formed, the residual tensile stress is preferably 48 MPa or less. In particular, it is preferable that the residual stress be 7 MPa or less. Reduction of the residual tensile stress is effective in preventing the light emitting portion from cracking.
In particular, the residual stress of the above glass is 3.5 MPa or less.

The tensile stress existing on the outer surface of the light emitting section 1 is
If the tensile strength limit of quartz glass is lower than about 48 MPa, there is no problem in the operation of the lamp. However, if the outer surface of the light emitting section 1 has a flaw, the larger the residual tensile stress is, the more the external force is applied to the light emitting section 1. Easily breaks (cracks). Therefore, the magnitude of the residual tensile stress is preferably 7 MPa or less, which is the designed tensile strength of general sheet glass. In a discharge lamp without an outer tube, the tensile stress is preferably smaller because it is easily affected by the outside.
It is preferably Pa (a safety factor of about 2: 1) or less.

The discharge lamp of the present invention is used as a mercury lamp in which mercury is sealed together with a rare gas inside the light emitting portion. In addition, a metal halide is sealed inside the light emitting portion together with a rare gas, and the light emitting portion is used as a metal halide lamp.

In the method for manufacturing a discharge lamp according to the present invention, in the (a) light emitting part forming step, the OH group content is 5 pp.
The quartz glass tube of m or less is heated and softened into a desired shape to form a light emitting portion. (a) In the electrode sealing step, the electrode assembly is inserted into the straight tube portion communicating with the light emitting portion, and the straight tube portion is heated and softened to seal the electrode. A dosing step (c) for charging a predetermined amount of a solid or liquid luminescent substance at room temperature into the light-emitting part, and then a gas filling step (d) for filling the light-emitting part with a predetermined amount of a rare gas and hermetically sealing the same; Is provided. The above manufacturing method can be applied to both single-ended and double-ended lamps.

In this manufacturing method, the dry rare gas to be filled in the light emitting portion in the gas filling step is present in the light emitting portion with respect to the main emission spectral spectrum intensity of the rare gas when a current of 3 mA is supplied and glow discharge is performed. The ratio of the maximum intensity of the emission spectrum of hydrogen, oxygen, and their compounds is 1
/ 1000 or less is used. In this manufacturing method, the OH in the quartz glass of the sealing portion after the gas filling step is used.
The group content is reduced to 5 ppm or less by weight.

In particular, the following method is preferable and adopted as a method for manufacturing a double-ended lamp. The manufacturing method is
(a) a light emitting portion forming step of heating and softening a quartz tube having one end closed and containing an OH group of 5 ppm or less by weight to form a light emitting portion having a predetermined shape; and (b) an open end of the quartz tube. First, the first electrode assembly is inserted into the straight tube portion leading to the arc tube portion, and is disposed at a predetermined position. After that, the quartz tube is evacuated from the open end and dried at atmospheric pressure or lower. An electrode sealing process in which gas is sealed, the open end is heated and softened and closed, and the quartz tube portion in which the first electrode assembly is disposed is heated and softened to seal the first electrode assembly. And (c) opening the closed end of the straight tube section leading to the light emitting section whose electrode is not yet sealed, and placing the solid or liquid luminescent substance at room temperature from the open end to the arc tube section. A dosing process for inserting only a fixed amount, and (d) a straight tube portion leading to the arc tube portion from the end opened in the dosing process, Inserting the second electrode assembly and arranging it at a predetermined position; (e) evacuating the quartz tube from the open end, enclosing a dry rare gas at atmospheric pressure or lower, and closing the open end. A gas filling step of heating and softening and closing, and (f) an electrode sealing step of heating and softening the quartz tube portion in which the second electrode assembly is disposed to seal the second electrode assembly. Including.

In the method of the present invention, in the gas filling step, when the completed discharge lamp is supplied with a current of 3 mA and glow discharged, 1/100 of the emission intensity of the rare gas is obtained.
A rare gas containing hydrogen, oxygen, and a compound thereof in an amount that has a maximum emission intensity of 0 or less is sealed. Furthermore, in the electrode sealing process of the first electrode assembly and the second electrode assembly, the quartz tube is heated and irradiated by laser or plasma.
Softens and seals the first and second electrode assemblies.

Another method of the present invention comprises the steps of (a) 5 pp by weight
(b) heating and softening a quartz tube containing an OH group of m or less to form a light emitting portion having a predetermined shape, and (b) a straight tube portion from the open end of the quartz tube to the light emitting tube portion. A dosing step of inserting the first electrode assembly and the second electrode assembly and disposing them at a predetermined position, and simultaneously inserting a predetermined amount of a solid or liquid luminescent substance into the arc tube at room temperature. ,
(c) evacuating the quartz tube from the open end, filling a dry rare gas below atmospheric pressure, heating and softening the open end to close it, and (d) a first gas filling step. An electrode sealing step of heating and softening the quartz tube portion on which the electrode and the second electrode assembly are arranged to seal the first electrode and the second electrode assembly.

In this manufacturing method, in the gas filling step, 1/1000 of the emission intensity of the rare gas when the completed discharge lamp is supplied with a current of 3 mA and glow discharged.
A rare gas containing hydrogen, oxygen, and a compound thereof in an amount that provides the following maximum emission intensity is sealed. Further, in the electrode sealing step of the first and second electrode assemblies, the quartz tube is heated and softened by laser or plasma irradiation, and the first and second electrode assemblies are sealed. The sealing of the two electrode assemblies takes place after the sealing of the first electrode assembly.

In common with the above-mentioned manufacturing methods, in the gas filling step, the water content of the rare gas to be sealed in the light emitting portion is
It is preferable that the molar ratio be 5 ppm or less.
pm or less. For this purpose, prior to the gas filling step, a step of preferably removing all or a part of hydrogen, oxygen and their compounds from the rare gas to be charged is included. As the means, cooling of the rare gas to be filled and solidification of moisture contained in the rare gas are employed.

Also in the light emitting portion forming step of the above manufacturing method, the light emitting portion can be formed by heating and softening the quartz glass tube by irradiating the quartz glass tube with laser or plasma. Further, the light emitting portion forming step may be performed in a dry rare gas or nitrogen gas atmosphere.

The above manufacturing method preferably includes a heating step of heating the quartz glass tube at a high temperature to remove the residual stress of the light emitting portion after the light emitting portion forming step. Thereby, the residual tensile stress in the light emitting section can be removed or reduced.

The above-mentioned manufacturing method preferably includes a desorption vacuum heat treatment step of removing water adsorbed on the glass surface heated in vacuum, and each step after the vacuum heat treatment step includes exposing the quartz glass surface to air. The lamp can be completed in an atmosphere of dry noble gas or nitrogen gas without drying. The moisture content of the dried rare gas or nitrogen gas is preferably 5 ppm or less, particularly preferably 1 ppm or less in molar ratio.

Such a desorption vacuum heat treatment step is performed prior to the light emitting portion forming step, and in particular, laser or plasma irradiation in the light emitting portion forming step is also used. This desorption vacuum heat treatment step can be performed after the light emitting part forming step and prior to the dosing step, or can be performed after the electrode sealing step and prior to the dosing step.

With respect to the light-emitting substance in the manufacturing method of the present invention, a vacuum heat treatment step of heat-treating the light-emitting substance in a vacuum may be added before or after the dosing step. In order to prevent oxidation of the luminescent material in the manufacturing process, in the electrode sealing step, the electrode is sealed by heating and softening the straight pipe portion extending from the light emitting unit while cooling a part of the light emitting unit. Is preferred.

In the electrode sealing step, it is preferable to heat and soften the straight tube portion and seal the electrode until the quartz glass in the straight tube portion and the electrode come into contact with each other at a high temperature.

[Embodiment] In FIG. 1A, the discharge lamp has a substantially spherical light emitting portion 1 made of quartz glass, and sealing portions 2a and 2b communicating with the light emitting portion 1 on both sides thereof. In 1, a pair of tungsten discharge electrodes 3, 3 for discharging a sealed gas by introducing an electric current are provided with protruding ends 30.

As shown in FIG. 1B, a molybdenum lead foil 4 is connected to the discharge electrode 3, and this lead foil is connected to an external current introducing lead wire 5 made of molybdenum. An electrode assembly 6 is formed. Electrode assembly 6
In the first embodiment, the base 31 of the discharge electrode 3, the entire lead foil 4, and a part of the leading end of the lead wire 5 are sealed with quartz glass to form sealed portions 2a and 2b of the discharge lamp.

The electrode assembly 6 employs a foil seal structure that absorbs a difference in thermal expansion between the molybdenum foil 4 and quartz glass due to plastic deformation of the molybdenum foil 4. In the example of the lamp shown in FIG. 1A, the inner volume of the light emitting unit 1 is about 0.45 cc.
The diameter of the tungsten electrode 3 is 0.45 mm, and the gap between the tungsten electrodes 3 in the spherical light emitting portion 1, that is, the distance between the electrodes is 1.5 mm.

In the light emitting section 1, in this example, an argon gas as a rare gas for assisting the starting of the lamp and mercury 7 as a luminescent substance are sealed to form a high-pressure mercury lamp. In the above example, the charged amount of mercury 5 is about 90 mg, and the charged amount of argon gas is 200 m at room temperature.
Sealed at bar pressure. Further, the glass of the light emitting portion 1 contains about 10 ppm by weight on average (average value of several places), and the glass of the sealing parts 2a and 2b contains about 5 ppm by weight ratio (average value of several places) of OH groups. I have.

FIGS. 2A and 2B show the spectral transmittance of the glass of each of the light emitting portion 1 and the sealing portions 2a and 2b in the infrared region (the horizontal axis is the wave number cm ^-1 , and the vertical axis is the transmittance). %), But the OH group content of the glass is about 3846 cm
^{-1 and} a transmittance of a wave number of about 3663 cm ^-1 .

FIG. 3 is an enlarged view of the vicinity of the interface between the electrode 3 and the glass of the sealing portion 2a shown in FIG. As shown by the hatched portion 10 in FIG. 3, in the discharge lamp of this embodiment, compressive stress remains in the glass near the interface of the electrode 3 in a direction parallel to the electrode direction. This residual stress is, for example, about 25 M
Pa. Further, the outer surface of the light emitting section 1 has a thickness of about 7 MPa.
Tensile stress.

Further, the discharge lamp of this embodiment has a light emitting section 1
When the amount of hydrogen, oxygen, and their compounds, for example, water present in the lamp is glow-discharged with a current of 3 mA, their emission intensity is 1/1000 or less of the intensity of the main emission spectrum of argon. It is said.

The measurement of the luminous intensity uses an automatic spectrometer. FIG. 4 shows a measuring device that can be used, which comprises an optical fiber 11 (3 m long) for receiving and transmitting a glow discharge of a discharge lamp, and a spectroscope 12 having a grating for diffracting the transmitted light and having a grating of 1200 G / mm. (Mac-Person, MC-209 type), a multi-channel type CCD detector 13 (Priston Instruments, TE / CCD1152UV type) for detecting diffracted light, and a CCD controller 14 (Priston type) for controlling the CCD detector 13 Instruments, Model ST-135)
A personal computer 15 (manufactured by NEC Corporation, model PC-9, which displays light detection data from the detector 13)
821).

FIGS. 5A and 5B show hydrogen (H; wavelength 656.2 nm) when the lamp of this embodiment shown in FIG. 1A is supplied with a current of 3 mA and glow-discharged. And oxygen (O; 777.2 nm, 777.4 nm, 777.5 n
m) is a result of spectroscopic measurement, wherein the horizontal axis represents wavelength (nm) and the vertical axis represents emission intensity (arbitrary scale). Light emission of both hydrogen and oxygen was not detected.

The discharge lamp of the embodiment having the above-described configuration was lit at a constant power of 150 W, and the change of the luminous flux maintenance ratio with respect to the lighting time was examined. Table 1 shows the results.

[0065]

[Table 1]

Table 1 also shows the results of the following three lamps (Comparatives A to C) as comparative examples. In the lamp of Comparative A, the OH group content of the glass of the sealing portions 2a and 2b is about 10%.
In ppm, the others were formed as in the example. When the lamp of Comparative B was glow-discharged with a current of 3 mA, the emission intensity of hydrogen (H), oxygen (O), and their compounds was 1/1 / 772.4 nm wavelength of argon.
Above 1000, the emission intensity was detected. Otherwise, the configuration is the same as that of the embodiment. The lamp of Comparative C has a sealing portion 2
When the lamps are glow-discharged at a current of 3 mA with an OH group content of the glasses a and 2b of about 10 ppm, the luminescence of hydrogen (H), oxygen (O), and their compounds,
Detected at 1/1000 or more of the wavelength of 772.4 nm of argon, and otherwise the same as in the example.

The lamps shown in the examples had a good luminous flux maintenance ratio of 90% after 10 hours, and were able to maintain 80% luminous flux even after 2,000 hours. On the other hand, the lamp A of the comparative example,
In B and C, the luminous flux maintenance ratio after 10 hours was poor at 80% or less. The lamps A, B, and C were severely blackened by visual observation, and were not turned on until 2000 hours (the luminous flux maintenance rate was 0%).
%).

As described above, the OH group content of the glass of the sealing portions 2a and 2b is as small as about 5 ppm, and the light emitting portion 1
When the amount of hydrogen (H), oxygen (O), and their compounds present in the lamp is glow-discharged with a current of 3 mA, the light emission is less than 1/1000 of the emission intensity of the rare gas. If it is not substantially detected, it can be understood that blackening due to long-time light emission is small and the luminous flux maintenance ratio is good, that is, the life is long.

This is because the amount of hydrogen (H), oxygen (O), and their compounds, which easily oxidize and evaporate the electrode 3 operating at a high temperature to promote the blackening of the light emitting portion 1, is small, and the light is turned on. Initial blackening is suppressed, and the sealing portions 2a, 2
This is because hydrogen (H), oxygen (O), and their compounds released from the glass as the lighting time increases due to the small number of OH groups in the glass of b.

Another feature of the lamp shown in this embodiment is that in the sealing portions 2a and 2b, the growth of cracks from the vicinity of the electrode 3 is suppressed, and leakage during lighting (airtight leakage) is small. This is due to the presence of compressive stress near the interface between the electrode 3 and the glass.

An example of the manufacturing method of the present invention will be described below with reference to the flowchart of FIG. (1) In the light emitting section forming step, the vicinity of the center of the quartz glass tube is heated and softened, and the light emitting section 1 is formed by molding. (2) In the first electrode sealing step, the electrode assembly 6 is inserted into one of the straight pipe portions adjacent to the light emitting section 1, heated and softened, and the electrode assembly 6 is sealed. 2a is formed.

(3) In the dosing step, the other straight pipe portion extending from the light emitting portion 1 (to become the sealing portion 2b)
Dosing the mercury 7 into the light emitting unit 1 through (4) In the gas filling step, the light emitting section 1 is passed through the same straight pipe section.
200 mbar of argon gas is sealed therein. (5) In the second electrode sealing step, the electrode assembly 6 is inserted into the last remaining straight pipe portion, and heated and softened to seal the electrode assembly 6 as in the first electrode sealing step. Then, the sealing portion 2b is formed.

In the discharge lamp manufacturing method of the present embodiment following the above flow, the process from (2) the first electrode sealing step to (5) the second electrode sealing step is performed in a dry argon gas atmosphere (dew point of about -76 ° C.). , The water content is about 1 ppm in molar ratio). The above method for manufacturing a discharge lamp does not include a high-temperature vacuum heat treatment for removing OH groups in glass.

(1) In the light emitting part forming step, FIGS. 7A to 7D show the procedure in FIG.
(A) As shown in FIG.
A quartz glass tube 60 having an inner diameter of about 2 mm is prepared. This quartz glass tube 60 contains about 5 ppm by weight of OH groups. Such a quartz glass tube is manufactured and sold, for example, by General Electric Company under the name 214 quartz tube, and is easily available.

Next, both ends of the quartz glass tube 60 are rotatable, and chucks (not shown) capable of moving toward and away from each other.
Hold with. Then, as shown in FIG. 7B, the central portion of the quartz glass tube 60 is heated and softened while rotating the quartz glass tube 60 as indicated by an arrow 62. This is arrow 6
This is performed with a propane burner indicated by 3. After the heating unit is softened, both ends of the quartz glass tube 60 are moved closer to each other as shown by an arrow 62 to form a thick portion 64 in the heating unit of the quartz glass tube 60.

Then, as shown in FIG. 7C, immediately after the heating is stopped, the molding die 66 is disposed around the thick portion 64. At the same time, a high pressure gas such as argon dried from the open end of the quartz glass tube 60 is supplied to the quartz glass tube 60.
Then, the thick portion 64 is expanded along the molding die 66 until the outer diameter becomes about 11 mm. Thus, FIG.
As shown in (D), the light emitting part 1 is formed in the quartz glass tube 67, and the light emitting part forming step is completed.

In the light emitting section 1 thus formed, the content of OH groups in the quartz glass increases to about 10 ppm. This is because water generated by the combustion of propane enters the glass heated by the propane burner. Also, when the molding die 66 is applied to the outer surface of the heated glass to form the light emitting unit 1, the temperature of the outer surface decreases more rapidly than the inner surface. Therefore, residual tensile stress remains on the outer surface of the light emitting section 1. In the light emitting section 1 having an outer diameter of about 11 mm,
It is about 7 MPa. The larger the outer diameter and thus the smaller the curvature, the greater the residual tensile stress. If the outer surface is forcibly cooled by spraying a nitrogen gas or the like, the residual tensile stress similarly increases.

Next, regarding the (2) first electrode sealing step of FIG. 6, the first electrode sealing step is performed in a dry argon gas atmosphere (dew point: about -76 ° C., water content: about 1 ppm). First, as shown in FIG. 8A, the electrode assembly 6 is inserted from one open end of the quartz glass tube 67 in which the light emitting unit 1 formed in the light emitting unit forming step is formed, and one end of the electrode 3 is connected to the light emitting unit. 1, the electrode assembly 6 is disposed inside the quartz glass tube 67.

Subsequently, in this state, as shown in FIG.
First, as shown by the arrow 61, the quartz glass tube 67 is rotated.
And a quartz glass tube 67 as shown by arrow 80
Internal pressure is 1 × 10^-3About Torr, particularly preferred
Is 1 × 10^-FourEvacuate to Torr. Then the arrow
As indicated by the mark 81, the surrounding atmosphere gas,
About 200 mbar of argon gas is introduced. Soshi
The end of the quartz glass tube 67 into which the electrode assembly 6 is inserted.
Heat, soften and seal. This is the CO indicated by arrow 82 _TwoLeh
Do it in the. If the inside of the quartz glass tube is airtight
For example, the end does not need to be melt-sealed with a laser.
If necessary, place a cap on the end or attach an on-off valve to
May be sealed.

Then, as shown in FIG. 8C, a portion of the quartz glass tube 67 near the electrode assembly 6 is heated by a CO ₂ laser indicated by an arrow 82. At this time, the quartz glass tube 67 is rotating as shown by the arrow 61.
The CO ₂ laser traverses from the electrode 3 to the molybdenum foil 4 over an appropriate length. However, the light emitting section 1 is not heated. At this time, the pressure inside the quartz glass tube 67 is 200 T
Since the heating portion is softened, the portion of the heated quartz glass tube 67 shrinks due to a pressure difference between the inside and the outside of the quartz glass tube 67.

The glass contacts and the heat is sufficiently transmitted to the electrode 3, so that the electrode 3 glows red and the molybdenum foil 4
At this time, the quartz glass tube 6 should be sufficiently airtight.
Heating is stopped when 7 shrinks. Irradiation diameter is about 6mm
A laser with an output of 200 W requires a heating time of about 30 seconds. Tungsten is about 10% of quartz glass
Since it has twice the expansion coefficient, when the heating is stopped and the electrode 3 cools, a compressive stress remains near the contact between the electrode 3 and the glass as described in FIG. This stress is, for example, about 25 MPa. The residual compressive stress in the sealing portion can be controlled by the heating time near the electrode 3 or the output of the laser. Increasing heating time and laser power
The stress increases. If the electrode 3 is controlled so as not to contact the glass, no stress is generated.

Finally, if the vicinity of the end (left side in FIG. 8C) of the straight tube portion adjacent to the light emitting portion 1 where the sealing portion 2a is not formed is cut (to seal the end portion with a cap or the like). When an opening valve is used, these are opened), and as shown in FIG. 8D, the light emitting unit 1 and one electrode assembly 6 are sealed, and the electrode 3 is closed.
A quartz glass tube 83 having a sealing portion 2a having a residual compressive stress near the contact between the glass and the glass is completed, and the first electrode sealing step is completed.

In the first electrode sealing step, since heating is performed by CO ₂ laser irradiation, OH in the glass is
An increase in the base amount is avoided. This is because laser heating does not generate water due to heating by a propane burner. Therefore, the amount of OH groups contained in the sealing portion 2a can be maintained at about 5 ppm, which is the same as that of the quartz glass tube 60 before processing. Therefore, high-temperature vacuum heat treatment for removing OH groups of glass is not particularly necessary. From the glass subjected to the high-temperature vacuum heat treatment, hydrogen gas and moisture that deteriorate the life characteristics of the lamp are easily released. The lamp processed and completed as described above emits little hydrogen gas and moisture from the glass,
Long life lamp.

[0084] Also in FIG. 8 (C), the in the process of heating the portion of the quartz glass tube 67 in the vicinity of the electrode assembly 6 by a CO ₂ laser, upon heating the quartz glass tube 67 by a CO ₂ laser, a heated If the quartz tube of the part shrinks, the sealing pressure in the tube is higher than 200 mbar, for example 300 m
Pressures from bar up to and above. Further, the inside of the tube can be made vacuum without filling gas. As the introduced gas, another gas, for example, a dry nitrogen gas can be used as long as the electrode assembly 6 is not oxidized during the heating.

In FIG. 8C, when the electrode assembly 6 is sealed, the heated portion of the quartz glass tube 67 contracts due to a pressure difference between the inside and the outside of the quartz glass tube 67, and also includes a pair of heated portions. It is also possible to pinch or squeeze with heat-resistant clip pieces. Further, the CO ₂ laser is moved laterally from the electrode 3 in the direction of the molybdenum foil 4 over an appropriate length. However, the CO ₂ laser may be moved in the direction of the electrode 3 from the direction of the molybdenum foil 4 or may be moved in a reciprocating manner. it can. Further, if the irradiation diameter is large enough to cover the required sealing width, there is no need to move in the lateral direction.

Next, the (3) dosing step of FIG. 6 will be described with reference to FIG. In the dosing step, as shown in FIG. 9, mercury 7 is introduced into the light emitting unit 1 from the open end of the quartz glass tube 83. This is performed by inserting the tubular needle 90 from the open end and stopping the needle when the tip comes near the center of the light emitting section 1. Tubular needle 90 is in communication with a dry source of argon gas, and this gas stream pushes mercury 7 through tubular needle 90. The dosing step is also performed in a dry argon gas atmosphere (dew point: about -76 ° C.), similarly to the first electrode sealing step.

Next, the (4) gas filling step and (5) the second electrode sealing step shown in FIG. 6 will be described. FIG. 10 (A)
As shown in the figure, a quartz glass tube 8 doped with mercury 7
The electrode assembly 6 is inserted from the opening end of the third electrode 3. The electrode assembly 6 is arranged such that one end of the electrode 3 is disposed in the light emitting section 1 at a position about 1.5 mm away from the tip of the electrode 3 on the sealing section 2a side.
Is arranged inside the quartz glass tube 83.

Subsequently, as shown in FIG. 10B, in this state, the quartz glass tube 83 is first rotated as shown by an arrow 61, and the quartz glass tube 8 is
3 is evacuated to a pressure of about 1 × 10 ⁻³ Torr. Thereafter, as shown by an arrow 81 in FIG. 10C, about 200 mbar of a dry surrounding argon gas (dew point: -76 ° C., water content of about 1 ppm in molar ratio) is introduced. Then, the vicinity of the opening of the quartz glass tube 83 in which the electrode assembly 6 is inserted is heated, softened and sealed by a CO ₂ laser indicated by an arrow 82.

Then, in FIG. 10D, the arrow 8
The portion of the quartz glass tube 83 near the unsealed electrode assembly 6 is heated by the CO2 laser shown in FIG. 2, and the second electrode is sealed in the same manner as in FIG.

As described above, the light emitting section 1 and the electrode assembly 6 are sealed as shown in FIG. 10 (E), and the sealing section 2a, which has a residual compressive stress near the contact between the electrode 3 and the glass, A quartz glass tube 90 having 2b and having the light emitting portion 1 hermetically filled with 200 mbar of argon gas and mercury 7 is completed, and the gas filling step and the second electrode sealing step are completed at the same time. Finally Figure 1
By cutting both ends of 0 (E) and exposing the lead wire 5 to the outside, the discharge lamp shown in FIG. 1 (A) is completed.

Another feature of the method for manufacturing the discharge lamp of the embodiment is that the electrode assembly 6 is sealed (first electrode sealing step; FIG. 8C and second electrode sealing step; FIG. 10).
(D)) is made in a state where both ends of the quartz tube are closed, so that the periphery of the molybdenum foil 4 can be securely hermetically sealed without bubbles of argon gas remaining. The glass tube is
At the same time, since both ends are closed, the intrusion of impurities from the outside of the quartz tube is completely suppressed.
It is suitable for the manufacture of lamps that do not contaminate the electrodes and extend the life. Further, since both ends are closed and the entry of impurities from the outside of the quartz tube is completely suppressed, a step of heating and softening the quartz tube 67 or 83 with a laser to seal the electrode assembly 6 (first electrode sealing). 8C and the second electrode sealing step; FIG. 10D) are performed in an atmosphere containing a relatively large amount of impurities that adversely affect the life, for example, in air.
You can do it.

Step of Sealing Electrode Assembly 6 First electrode sealing step; FIG. 8C and second electrode sealing step; FIG.
In (D)), a relatively large amount of quartz (SiO ₂ ) and silicon (Si) evaporate due to long-time laser heating, which lowers the cleanliness of the argon atmosphere. As a result, the substance inserted into the arc tube 1 may be contaminated, and the life of the finally completed lamp may be shortened. This often requires a lot of expense and time to remove the evaporated quartz or silicon from the argon atmosphere. Therefore, since the both ends are closed, the manufacturing method of this embodiment, which can perform laser heating in a place other than the argon gas atmosphere, eliminates the concern that the dosing step or the gas filling step is contaminated with the evaporating quartz or silicon. A clean lamp can be manufactured.

As described above, vacuum evacuation was performed to at least about 1 × 10 ⁻³ Torr in FIG.
In FIG. 10 (C), the completed lamp was filled with argon gas containing about 1 ppm of water. When the lamp was glow-discharged with a current of 3 mA, hydrogen (H), oxygen (O), and their compounds The emission intensity is 1 of the emission intensity of argon.
/ 1000 or less, which is not substantially detected, but the value of the ultimate vacuum degree of the vacuum evacuation and the water content of the enclosed argon gas exemplified here are preferable and sufficient conditions. For example, 5p
Argon gas containing moisture of about pm (dew point: about -65 ° C.) is acceptable.

From the viewpoint of life, it is more preferable that the ultimate degree of vacuum of the vacuum evacuation is higher and the moisture content of the enclosed argon gas is lower. At present, the ultimate vacuum degree can be easily obtained at about 1 × 10 ⁻¹⁰ Torr by increasing the evacuation capacity of the vacuum pump. The lower limit of the water content of the argon gas is practically 0.001 ppm in molar ratio (dew point: about -110 ° C).
It is about. This value is almost equal to the detection limit. From the above points, the moisture content of the argon gas to be enclosed is 0.001.
The range is from ppm to 1 ppm.

The moisture content of the surrounding atmosphere gas in which each step is performed is in the range of 5 ppm or less, preferably 0.001 ppm to 1 ppm in terms of molar ratio in consideration of the fact that the atmosphere gas can be used as the sealing gas in the light emitting portion. Is available. To reduce the water content of the argon gas, make the argon gas source of higher purity and introduce the gas into the quartz tube via a means for removing the moisture, rather than introducing the gas directly into the lamp. It is more practical.

As a means for removing water, a cooling device can be used as shown in FIG. In this apparatus, an argon gas shown by an arrow 101 is passed through a stainless steel tube 100, and liquid nitrogen shown by an arrow 102 is blown in a stainless steel container 103 to be cooled to a temperature of -76 ° C or less.
Reduce the vapor pressure of water in argon. For example, when the spray amount of the liquid nitrogen 102 is controlled so that the argon gas is cooled to −110 ° C., the amount of water contained in the argon gas can be reduced to about 0.001 ppm in molar ratio. Argon gas can reduce its temperature to its melting point -190C. Its water content is about 9.2
It can be reduced to × 10 ⁻¹² ppm.

Further, in this case, an effect is obtained that the amount of water in the argon gas 101 can be indirectly controlled by the temperature of the refrigerant. Maintain from the manufacturing process that directly controls the moisture content of the gas (this is very expensive and requires a high-precision analyzer)
Easy to manage and practical. Alternatively, the means for removing water may use a chemical or physical adsorbent such as alumina.

In FIG. 10D, in order to prevent the mercury 7 in the light emitting section 1 from evaporating during the laser heating, for example, argon gas is blown to the light emitting section 1 at a relatively high pressure, and Can be cooled. In addition, a tube through which a coolant such as water or liquid nitrogen flows can be brought into contact with the light emitting unit 1 or disposed around the light emitting unit 1 to cool the light emitting unit.

In the present embodiment, a method of manufacturing a discharge lamp in which mercury is sealed as a luminescent material has been described as an example. However, a metal halide lamp to which a metal halide is added can be manufactured by a similar manufacturing method. In this case, as shown in FIG. 12, following the dosing step, a vacuum heat treatment for heating the quartz glass tube 83 of FIG. 9 in a vacuum can be added. This is effective for removing water from a metal halide having a high adsorptivity, and has a strong effect of suppressing blackening and devitrification of a metal halide lamp. Such a vacuum heat treatment of the luminescent material may be performed before the dosing step. However, it is necessary to avoid that the luminescent material touches the air after the heat treatment.

The manufacturing method of this embodiment can also manufacture a rare gas discharge lamp in which mercury is not sealed. In this case, the dosing step can be omitted.

After the light emitting section 1 is formed, a heat treatment step may be added to reduce the residual tensile stress of the light emitting section.

Further, in the light emitting portion forming step, it is also possible to process with a CO ₂ laser. In this case, O
The amount of H base is the same as the quartz glass tube 60 before processing, about 5 pp.
m. This step of forming the light emitting section 1 having a small number of OH groups is particularly effective for manufacturing a metal halide lamp. Fewer OH groups further suppress the reaction between glass and metal halide.

Further, by using a CO ₂ laser, FIG.
As shown in FIG. 3, the steps from the light emitting part forming step to the lamp completion can be performed in a dry argon gas atmosphere. Further, as shown in FIG. 14, a step of removing water adsorbed on the glass surface may be added. In this step, the glass is subjected to vacuum heat treatment at a temperature in the range of 100C to 1000C. The preferred temperature range is 400 ° C to 60 ° C.
0 ° C. If the glass is processed without being exposed to the atmosphere after this step, no adsorbed moisture remains in the light emitting portion 1 as an impurity, and thus a discharge lamp having a longer life can be manufactured. This glass vacuum heat treatment step can be inserted between the light emitting portion forming step and the first electrode sealing, or between the first electrode sealing and the dosing step. After the heat treatment, the temperature of the glass is preferably maintained at 100 ° C. to 300 ° C. to complete each step, and the effect of removing adsorbed water is higher.

In the processing of the sealing portion, laser irradiation
O ₂ laser or YAG laser can be used, and argon plasma can be used for plasma irradiation. The starting material quartz glass preferably has an OH group content of about 5 ppm or less, and in particular, quartz glass having a smaller OH group content is used. In this embodiment, argon gas is sealed as a rare gas, but xenon gas and krypton gas are also used as the rare gas. The method for manufacturing the discharge lamp of the present invention is not affected by the type of the rare gas to be filled.

In this embodiment, the discharge lamp is manufactured in a dry argon atmosphere. However, the discharge lamp can be replaced with another dry non-oxidizing gas, for example, nitrogen gas. Light emitting unit 1
Laser sealing work of the sealing parts 2a and 2b which does not have to worry about the inside being exposed to the atmosphere (shown in FIG. 8 (d) and FIG. 10 (d))
Can be performed in air.

A method of manufacturing a modified discharge lamp according to this embodiment will be described with reference to FIGS. In the manufacturing method shown in FIG. 6, (2) the first electrode sealing step, (3) the dosing step, (4) the gas filling step, and (5) the second electrode sealing step It is characterized by performing.

First, in the bulb molding step, the light emitting portion 1 is formed, and a quartz tube 150 having both ends opened is prepared. The electrode assembly 6 is inserted from one end A of the quartz tube 150, and one end of the electrode 3 is inserted into the light emitting portion 1. Electrode assembly 6 so as to be arranged at a predetermined position.
Are arranged (FIG. 15A). Next, mercury 7 is introduced into the light emitting section 1 from the other open end B through the tubular needle 90 (FIG. 15B; dosing step). Then the same one end B
Then, another electrode assembly 6 is inserted, and the electrode assembly 6 is arranged so that one end of the electrode 3 is also arranged at a predetermined position in the light emitting section 1 (FIG. 15C).

Next, as shown in FIG. 15D, the glass tube 67 is rotated in this state as shown by an arrow 61 (not shown, but this operation is performed in the vicinity of both ends of the quartz tube 150). This is done by holding the chuck with a rotatable chuck and rotating the chuck), and as shown by an arrow 80, evacuate the inside of the quartz tube 150 from both ends A and B until the pressure becomes 1 × 10 ⁻³ Torr or less. Exhaust. Thereafter, a dry argon gas (arrow 81) containing less than 5 ppm of water, preferably 1 ppm or less of water, is introduced around 200 mbar. Then, both ends of the quartz tube 150 are heated, softened, and sealed (gas filling step). This heating for sealing is performed by a CO ₂ laser as shown by an arrow 82.

Subsequently, the portion of the quartz tube 150 near the electrode assembly 6 is heated and softened by a CO ₂ laser over a suitable length from the electrode 3 to the molybdenum foil 4 to seal the two electrode assemblies 6. (FIG. 15E; first electrode and second electrode sealing step). The sealing of the two electrode assemblies 6 may be performed simultaneously or one by one. Finally Figure 1
If both ends of 5 (E) are cut and the lead wire 5 is drawn out, a discharge lamp having the structure shown in FIG. 1 is completed (FIG. 15 (F)).

According to a method of manufacturing a discharge lamp in which the embodiment shown in FIGS. 15A to 15F is modified, (2) first electrode sealing step, (3) dosing step, and (4) shown in FIG. ) Since the gas filling step and the (5) second electrode sealing step are performed simultaneously, the time required for production can be greatly reduced, and therefore, a discharge lamp having the structure shown in the embodiment can be easily provided. . At the same time, before the dosing step, as shown in FIG. 8D, the closed end of the quartz tube is not cut before the dosing step. For this reason, small glass fragments generated when the quartz tube is cut are completely prevented from entering the inside of the quartz tube, that is, the light emitting section 1. Therefore, impurities in the light emitting section 1 can be reduced to an extremely small extent, and a discharge lamp having a longer life can be provided.

[0111]

According to the discharge lamp of the present invention, the amount of hydrogen (H), oxygen (O), and their compounds present in the light-emitting portion is reduced in the light detection time when glow discharge is performed at a low current. Is substantially not detected, and the OH group content of the quartz glass forming the sealing portion is set to a weight ratio of more than 0 to 5 ppm or less. Blackening and devitrification of the inner surface of the light emitting portion glass due to oxygen and water can be prevented, and a longer life can be realized.

In the lamp of the present invention, the residual compressive stress was formed in the vicinity of the contact interface with the electrode in the quartz glass of the sealing portion, so that the adhesion between the glass and the electrode was high, and the crack from the vicinity of the electrode 3 was cracked. Growth is suppressed and leakage during lighting (airtight leakage) can be reduced.
The metal halide is prevented from penetrating into the vicinity of the interface between the electrode 3 and the glass having a low temperature, thereby preventing a decrease in vapor pressure of the metal halide, thereby improving the light emission characteristics.

In the method of manufacturing a discharge lamp according to the present invention, the amount of hydrogen, oxygen and their compounds present in the light emitting portion is glow-discharged at a low current by regulating the water content in the rare gas to be filled. When the lamp is in use, it is possible to prevent blackening and devitrification of the inner surface of the light emitting part glass due to hydrogen, oxygen, and water in the light emitting gas. As a result, a lamp having a long life can be manufactured.

In the method for manufacturing a discharge lamp according to the present invention, in the step of sealing the first and second electrode assemblies in a sealing portion,
After reducing the pressure inside the tube and sealing the both ends of the glass tube containing the rare gas, the quartz tube is heated and softened and sealed, so that the content of OH groups in the sealed portion can be reduced, and oxidation and contamination of the electrode can be prevented. This is effective in preventing blackening and devitrification of the lamp inner surface during long-term lamp use.

In the method of the present invention, further, in the sealing step of the electrode assembly, the quartz tube can be heated and softened by laser or plasma irradiation and sealed, and the content of the OH group in the glass at the sealed portion can be increased. And a discharge lamp in which blackening or devitrification of the inner surface of the lamp during long-term use of the lamp is prevented by reducing the OH group content.

[Brief description of the drawings]

FIG. 1 is a sectional view (A) of a discharge lamp according to an embodiment of the present invention.
And a perspective view (B) of an electrode assembly used for this.

FIG. 2 is a graph (A, A) showing the glass spectral transmittance of the light emitting portion and the sealing portion of the discharge lamp according to the present embodiment.
B).

FIG. 3 is a partial sectional view of a sealing portion of the discharge lamp according to the embodiment of the present invention.

FIG. 4 is a conceptual diagram of an apparatus for measuring emission intensity during glow discharge of a discharge lamp according to an embodiment of the present invention.

FIG. 5 is a graph (A, B) showing the spectral intensity at the time of glow discharge of the discharge lamp of the present embodiment.

FIG. 6 is a flowchart showing a manufacturing process of the discharge lamp according to the embodiment of the present invention.

FIG. 7 shows a manufacturing method according to an embodiment of the present invention.
Sectional drawing (A-D) of the quartz tube for showing the process of shape | molding the light emission part of a discharge lamp.

FIG. 8 illustrates a manufacturing process according to an embodiment of the present invention.
Sectional drawing (A-D) of the quartz tube which shows the 1st electrode sealing process of a discharge lamp.

FIG. 9 is a cross-sectional view of a quartz tube for illustrating a dosing step in the process of manufacturing the discharge lamp according to the embodiment of the present invention.

FIG. 10 is a sectional view (A to E) of a quartz tube for illustrating a gas filling step and a second electrode sealing step according to the embodiment of the present invention.

FIG. 11 is a cross-sectional view showing an apparatus for removing moisture in a sealed gas prior to a gas filling step according to the embodiment of the present invention.

FIG. 12 is a flowchart illustrating a manufacturing process of the discharge lamp according to the embodiment of the present invention.

FIG. 13 is a flowchart showing a process of manufacturing a discharge lamp according to another embodiment of the present invention.

FIG. 14 is a flowchart showing a process of manufacturing a discharge lamp according to another embodiment of the present invention.

FIG. 15 is a cross-sectional view of a quartz tube (A to F) for illustrating a manufacturing process of the discharge lamp according to the embodiment of the present invention.

FIG. 16 is a sectional view (A, B) of a quartz tube for illustrating a method of manufacturing a conventional discharge lamp.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light-emitting part 2a Sealing part 2b Sealing part 3 Tungsten electrode 4 Molybdenum foil 7 Mercury 6 Tungsten thin film 82 Laser

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01J 61/30 H01J 61/30 C 61/36 61/36 B

Claims (32)

[Claims] 1. A discharge comprising a light emitting portion made of quartz glass, an electrode disposed in the light emitting portion, a sealing portion sealing quartz electrode made of quartz glass, and a rare gas hermetically filled in the light emitting portion. A light emission spectrum of hydrogen, oxygen, and their compounds present in the light emitting part with respect to the main light emission spectral intensity of the rare gas when a current of 3 mA is supplied to an electrode in the light emitting part and glow discharge is performed. The ratio of the maximum strength is less than 1/1000 and the OH group content in the quartz glass of the sealing portion is 5 by weight.
A discharge lamp that is less than or equal to ppm. 2. The discharge lamp according to claim 1, wherein the quartz glass of the sealing portion has a residual compressive stress near an interface region with the electrode. 3. The discharge lamp according to claim 3, wherein the residual compressive stress is not less than 25 MPa and not more than the crushing strength of the glass. 4. The discharge lamp according to claim 1, wherein the OH group content in the quartz glass of the light emitting portion is 10 ppm or less by weight and the residual tensile stress in the quartz glass is 48 MPa or less. 5. The discharge lamp according to claim 4, wherein the residual tensile stress in the quartz glass of the light emitting section is 7 MPa or less. 6. The discharge lamp according to claim 4, wherein the residual tensile stress is 3.5 MPa or less. 7. The discharge lamp according to claim 4, wherein the OH group content in the quartz glass of the light emitting portion is 5 ppm or less by weight ratio. 8. The discharge lamp according to claim 1, wherein mercury is sealed together with a rare gas inside the light emitting portion. 9. The discharge lamp according to claim 1, wherein a metal halide is sealed inside the light emitting section together with a rare gas. 10. A light emitting part forming step of: (a) heating and softening a quartz glass tube containing an OH group having a weight ratio of 5 ppm or less to form a light emitting part of a predetermined shape; and (b) a step of directly forming a light emitting part. An electrode sealing step of inserting the electrode assembly into the tube portion, heating and softening the straight tube portion to seal the electrode assembly, and (d) filling the light emitting portion with a predetermined amount of a rare gas to airtightly. A method of manufacturing a discharge lamp including a gas filling step of sealing, wherein the dry rare gas to be filled in the gas filling step is supplied with a current of 3 mA and glow-discharges the main light emission of the rare gas. The ratio of the maximum intensity of the emission spectrum of hydrogen, oxygen, and their compounds present in the light emitting portion to the spectral spectrum intensity is 1/1000 or less, and OH in the quartz glass of the sealing portion after the gas filling step. Discharge lamp having a base content of 5 ppm or less by weight Manufacturing method. 11. The discharge lamp according to claim 10, further comprising: (c) a dosing step of charging a predetermined amount of a solid or liquid luminescent substance at room temperature into the light emitting section after the electrode sealing step and before the gas filling step. Production method. 12. A light emitting portion forming step of heating and softening a quartz tube having one end closed and containing a OH group having a weight ratio of 5 ppm or less to form a light emitting portion having a predetermined shape, and (b) quartz. From the open end between, insert the first electrode assembly into a straight tube portion that leads to the arc tube portion, place it in a predetermined position, and then evacuate the quartz tube from the open end portion and reduce the pressure to below atmospheric pressure. Sealing the first electrode assembly by enclosing the dried rare gas, closing the open end, heating and softening the quartz tube portion where the first electrode assembly is disposed, and sealing the first electrode assembly. (C) Open the closed end of the straight tube portion that leads to the light emitting portion whose electrode is not yet sealed, and apply a predetermined amount of a solid or liquid luminescent substance at room temperature from the open end to the light emitting tube portion. And (d) from the end opened in the dosing process into the straight pipe section leading to the arc tube section. Placing in position by inserting the electrode assembly, by sealing (e) the quartz tube from the open end portion is evacuated, the following dry noble gas atmosphere,
A gas filling process in which the open end is heated and softened to close it,
(f) an electrode sealing step of heating and softening the quartz tube portion where the second electrode assembly is disposed to seal the second electrode assembly;
In the gas filling step, the completed discharge lamp is 3 mA
An amount of hydrogen that has a maximum luminous intensity of 1/1000 or less of the luminous intensity of the rare gas when glow discharge is performed by supplying a current of
Enclose a rare gas containing oxygen and their compounds, heat and soften the quartz tube by laser or plasma irradiation in the electrode sealing process of the first electrode assembly and the second electrode assembly, A method for manufacturing a discharge lamp for sealing a second electrode assembly. 13. A light emitting section forming step of: (a) heating and softening a quartz tube containing an OH group having a weight ratio of 5 ppm or less to form a light emitting section having a predetermined shape; and (b) an open end of the quartz tube. From the part, the first electrode assembly and the second electrode assembly are inserted into the straight tube part leading to the arc tube part and arranged at a predetermined position, and at the same time, solid or liquid at room temperature is inserted into the arc tube part. A dosing step of inserting a predetermined amount of a luminescent substance, and (c) a gas in which the quartz tube is evacuated from the open end, filled with a dry rare gas at atmospheric pressure or lower, and heated and softened to close the open end. A filling step, and (d) an electrode sealing step of heating and softening the quartz tube section in which the first electrode and the second electrode assembly are arranged to seal the first electrode and the second electrode assembly. And a stopping step, wherein the completed discharge lamp is provided in a gas filling step. The emission intensity of the noble gas when the flop by supplying 3mA current to the glow discharge 1/10
A rare gas containing an amount of hydrogen, oxygen and a compound thereof having a maximum emission intensity of 00 or less is sealed, and in the electrode sealing process of the first and second electrode assemblies, the quartz tube is irradiated with laser or plasma. A method for manufacturing a discharge lamp that heats and softens and seals the first and second electrode assemblies. 14. The method according to claim 13, wherein the step of sealing the second electrode assembly is performed after the step of sealing the first electrode assembly. 15. The method for manufacturing a discharge lamp according to claim 10, wherein in the gas filling step, the water content of the rare gas to be sealed in the light emitting portion is 5 ppm or less in molar ratio. 16. The method for manufacturing a discharge lamp according to claim 10, wherein the water content in the rare gas to be sealed in the light emitting portion in the gas filling step is 1 ppm or less in molar ratio. 17. The discharge lamp according to claim 10, further comprising a step of removing all or a part of hydrogen, oxygen, and a compound thereof from a rare gas to be charged before the gas charging step. Manufacturing method. 18. The method according to claim 1, wherein in the removing step, the rare gas to be filled is cooled to solidify moisture contained in the rare gas.
8. The method for manufacturing a discharge lamp according to item 7. 19. The light emitting unit forming step, wherein the light emitting unit comprises:
19. The method for manufacturing a discharge lamp according to claim 10, wherein the quartz glass tube is heated and softened by irradiating the quartz glass tube with laser or plasma. 20. The method for manufacturing a discharge lamp according to claim 19, wherein the light emitting portion forming step is performed in a dry rare gas or nitrogen gas atmosphere. 21. The method according to claim 20, wherein the manufacturing method comprises:
21. The method for manufacturing a discharge lamp according to claim 10, further comprising a heat treatment step of heating the quartz glass tube at a high temperature to remove a residual stress of the light emitting portion. 22. The manufacturing method includes a desorption vacuum heat treatment step of removing water adsorbed on a glass surface heated in a vacuum,
Each step after the vacuum heat treatment step is performed in an atmosphere of a rare gas or a nitrogen gas in which at least the inner surface of the light emitting portion or the inner surface of the quartz glass to be the light emitting portion is dried without being exposed to air. Claim 1 to complete
22. The method for manufacturing a discharge lamp according to any one of 0 to 21. 23. The discharge lamp according to claim 22, wherein the desorption vacuum heat treatment step is performed prior to the light emitting section forming step, and the light emitting section forming step is performed by heating and softening the quartz glass tube by laser or plasma irradiation. Production method. 24. The method for manufacturing a discharge lamp according to claim 22, wherein the desorption vacuum heat treatment step is performed after the light emitting part forming step and before the dosing step. 25. The method according to claim 22, wherein the desorption vacuum heat treatment step is performed after the electrode sealing step and before the dosing step. 26. The dry noble gas or nitrogen gas,
26. The composition according to claim 22, which contains water in a molar ratio of 5 ppm or less.
The method for producing a discharge lamp according to any one of the above. 27. The dry noble gas or nitrogen gas is
27. The method for producing a discharge lamp according to claim 26, wherein the method contains water in a molar ratio of 1 ppm or less. 28. The method of manufacturing a discharge lamp according to claim 22, wherein a vacuum heat treatment step of heat-treating the luminescent material in a vacuum is added before or after the dosing step. 29. The electrode according to claim 10, wherein in the electrode sealing step, the electrode is sealed by heating and softening a straight pipe portion extending from the light emitting unit while cooling a part of the light emitting unit. Of manufacturing a discharge lamp. 30. The electrode sealing process according to claim 10, wherein in the electrode sealing step, the straight tube portion is heated and softened until the quartz glass in the straight tube portion comes into contact with the electrode at a high temperature, and the electrode is sealed. Manufacturing method of discharge lamp. 31. The rare gas is an argon gas.
10. The discharge lamp according to any of claims 9 to 9. 32. The rare gas is an argon gas.
31. The method for producing a discharge lamp according to any one of 0 to 30.