JPH11135021A - Manufacture of ceramic discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method surely capable of manufacturing a ceramic discharge lamp having little water molecular amount existing in an arc tube and having expected lamp characteristics with comparatively low cost facilities. SOLUTION: This method has a process (A) of conducting degassing treatment by heating arc tube material 10a comprising translucent ceramics having a sealing tube portion 12 formed at its end portion and an electrode mount 20 respectively under reduced pressure and a process (B) of arranging the degassed electrode mount 20 in the degassed arc tube material 10a and fixing the electrode mount 20 onto the inner face of the sealing tube portion 12 of the arc tube material 10a. In the process (B), when the surface temperature of the arc tube material 10a and the electrode mount 20 is assumed to be t( deg.C) and the dew point of a low humidity atmosphere is assumed to be dp( deg.C), a following expression is satisfied; t>=2×(100+dp).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a ceramic discharge lamp in which an arc tube is made of a ceramic having translucency.

[0002]

2. Description of the Related Art For example, a discharge lamp such as a high-pressure or low-pressure mercury discharge lamp or a metal halide lamp is used as a light source for a backlight of a liquid crystal display device or a light source of an ultraviolet ray processing device. In such discharge lamps, conventionally, an arc tube made of silica glass has been used, but recently, polycrystalline alumina, polycrystalline yttrium-aluminum-garnet (hereinafter, referred to as polycrystalline alumina) have been used.
Abbreviated as "YAG". ), And those made of translucent ceramics such as polycrystalline yttria have begun to be used. Discharge lamps having an arc tube made of such ceramics, that is, ceramic discharge lamps, have higher mechanical strength and heat-resistant temperature of the arc tube than a discharge lamp having an arc tube made of conventional silica glass,
This is advantageous in that it has excellent corrosion resistance to a specific metal element sealed in the arc tube.

[0003] However, such a ceramic discharge lamp has the following problems. In the manufacture of a discharge lamp having a silica glass arc tube, once the arc tube material is subjected to a vacuum degassing process, the arc tube material is then exposed to the atmosphere so that, for example, water molecules are present on its surface. Even by adsorption, water molecules adsorbed on the surface can be removed by performing vacuum heating at about 400 ° C. again on the arc tube material,
As a result, the amount of water molecules taken into the arc tube of the completed discharge lamp can be reduced. Anyway, YA
Light-transmitting ceramics such as G are more difficult to remove water molecules adsorbed on the surface than silica glass. Therefore, in the production of a ceramic discharge lamp, even if the arc tube is once subjected to vacuum degassing, the arc tube is then exposed to the air, so that water molecules are adsorbed on its surface. In some cases, water molecules adsorbed on the surface cannot be removed by vacuum heating at about 400 ° C., and eventually, it is necessary to perform vacuum degassing again on the arc tube material at a high temperature of 800 ° C. or higher. When the water molecules adsorbed on the inner surface of the arc tube are released into the discharge space, the water molecules cause an increase in a starting voltage, a blackening phenomenon of the arc tube, and the like. It is difficult to obtain a discharge lamp.

[0004] Specifically, the following has been found regarding the relationship between the amount of water molecules taken into the arc tube and the lamp characteristics of the obtained discharge lamp when the discharge lamp is manufactured. (1) Lamp starting characteristics: When water molecules are taken into the arc tube, the starting voltage of the lamp increases. When the concentration in the arc tube becomes about 1000 ppm for hydrogen molecules and several hundred ppm for water molecules, the discharge lamp has a problem in starting performance at the time of lighting. (2) Blackening phenomenon of the arc tube: When water molecules are taken into the arc tube, during the operation of the discharge lamp, the water molecules dissociate in an arc and react with tungsten as an electrode substance, thereby causing tungsten oxidation. Object (WO ₂ or W
O ₃ ) is produced, and this tungsten oxide evaporates and adheres to the inner wall of the arc tube. Then, the tungsten oxide attached to the inner wall of the arc tube is reduced by hydrogen molecules, so that tungsten and water molecules are generated on the inner wall of the arc tube. Due to such a phenomenon (so-called water cycle), the electrode material is transported from the electrode to the inner wall of the arc tube, thereby causing a blackening phenomenon of the arc tube. In particular, in a metal halide lamp, the solubility of tungsten in the gas phase is increased by hydrogen molecules, so that the blackening of the arc tube tends to occur early.

In order to solve such a problem, in the production of a ceramic discharge lamp, the degassing-treated arc tube material and the electrode mount are not exposed to the atmosphere, but are exposed to an extremely low moisture concentration, for example, in an environment. It is carried into a glove box in which the dew point of the atmosphere is controlled to −80 ° C. or less by a gas purifier, and in this glove box, an assembling / sealing process of an arc tube material and an electrode mount is performed. However, in order to control the dew point of the atmosphere in the glove box to −80 ° C. or less,
As a gas purifier, one having a considerably high capacity is required, and there is a problem that the cost of lamp manufacturing equipment is increased.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been made based on the above circumstances, and its object is to provide:
It is an object of the present invention to provide a method capable of reliably producing a ceramic discharge lamp having a desired lamp characteristic with a small amount of water molecules present in an arc tube by using relatively inexpensive equipment.

[0007]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have conducted intensive studies. As a result, after performing degassing treatment of the arc tube material and the like, the surface temperature of the arc tube material and the like are reduced to the atmosphere. By maintaining a certain temperature in relation to the dew point of
The inventors have found that the adsorption of water molecules to the arc tube material and the like is suppressed, and have completed the present invention. That is, the method for manufacturing a ceramic discharge lamp of the present invention is a method for manufacturing a ceramic discharge lamp including an arc tube made of a translucent ceramic, in which a sealing tube portion is formed at an end. A step (A) of degassing each of the arc tube material and the electrode mount made of translucent ceramics by heating them under reduced pressure; (B) arranging the degassed electrode mount and fixing the electrode mount to the inner surface of the sealing tube portion of the luminous tube material. In the step (B), the luminous tube material and the electrode When the surface temperature of the mount is t (° C.) and the dew point of the low humidity atmosphere is dp (° C.), the following formula (1) is satisfied. Formula (1) t ≧ 2 × (100 + dp)

In the method of manufacturing a ceramic discharge lamp according to the present invention, the dew point of the low humidity atmosphere in the step (B) is preferably -80 to -40 ° C.

In the method for manufacturing a ceramic discharge lamp according to the present invention, in the initial stage of the step (B),
The surface temperature of the arc tube material and the electrode mount is a temperature higher than the lower limit of the temperature defined by the above formula (1), and the surface temperature of the arc tube material and the electrode mount is lower than the temperature defined by the formula (1). The step (B) may be completed before the lower limit is reached.

[0010]

According to such a method, after degassing each of the arc tube material and the sealing material, the surface temperature of the arc tube material and the electrode mount is related to the dew point of the low humidity atmosphere in a low humidity atmosphere. In the state maintained at a specific temperature by assembling the arc tube and the electrode mount, and fixing the electrode mount to the sealing tube portion of the arc tube, the amount of water molecules adsorbed on the arc tube and the electrode mount is extremely small. Constrained by value.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing a ceramic discharge lamp according to the present invention will be described in detail. FIG. 1 is an explanatory cross-sectional view showing a configuration of an example of a ceramic discharge lamp obtained by the manufacturing method of the present invention. In this ceramic discharge lamp, a luminous tube 10 made of a translucent ceramic is provided in which sealing tube portions 12 are formed at both ends of a substantially spherical discharge space surrounding portion 11 surrounding a discharge space S. I have. In the arc tube 10, electrode mounts 20 each having an electrode 21 and arranged such that the electrodes 21 face each other along the tube axis in the discharge space surrounding portion 11 are arranged.

More specifically, each of the electrode mounts 20 is provided at its tip with a rod-shaped electrode 21 made of tungsten, which is wound around a coil made of tungsten and extends in the tube axis direction of the arc tube 10. A sleeve member 22 having an outer diameter matching the inner diameter of the sealing tube portion 12 of the arc tube 10 is fitted to the base end of the electrode 21, and the base end of the electrode 21 has the same direction as the electrode 21. A bar-shaped lead member 23 is integrally provided. The lead member 23 of the electrode mount 20 is formed by integrally connecting an inner portion 23a located inside the sealing tube portion 12 of the arc tube 10 and an outer portion 23b other than the inner portion 23a by welding or the like. The inner portion 23a is made of niobium, and the outer portion 23 of the lead member 23 is formed.
b is an oxidation-resistant metal or alloy (for example, Pt or Pt) when forming a single tube discharge lamp which is not a double tube.
-Ir alloy). A positioning projection 24 for positioning the electrode mount 20 is formed on an inner portion of the lead member 23 in a manufacturing method described later, and a sealing material described later is formed on an outer portion of the lead member 23. A holding flange 25 for holding is formed. The lead member 23 of the electrode mount 20 is connected to the arc tube 1 by the sealing member 30.
0 is hermetically sealed to the inner surface of the sealing tube portion 12. A discharge gas and a necessary solid luminescent material are sealed in the discharge space surrounding portion 11 of the arc tube 10.

As the ceramics forming the arc tube 10, translucent polycrystalline alumina, translucent polycrystalline yttrium-aluminum-garnet, and translucent polycrystalline yttria can be used. As a material for forming the sleeve member 22 in the electrode mount 20, polycrystalline alumina, alumina-tungsten cermet, silica glass, or the like can be used. As a material constituting the sealing member 30, an alumina-silica-rare earth oxide-based sealing material, an alumina-calcia-based sealing material, or the like can be used.

In the present invention, in order to manufacture the above-described ceramic discharge lamp, for example, a glove box device having a configuration shown in FIG. 2 is used. In FIG. 2, reference numeral 40 denotes a glove box, which is provided with a work glove 41 for performing work from outside. An appropriate gas purifier (not shown) for connecting the glove box 40 to a low-humidity atmosphere is connected to the glove box 40. As such a gas purifier, a gas purifier that replaces the air in the glove box 40 with an inert gas and circulates the inert gas into the glove box 40 through a processing tank in which a molecular sieve is arranged is used. Can be used. Reference numeral 50 denotes a degassing chamber, which is connected to the glove box 40 via a first partition 42 provided to be openable and closable,
A vacuum pump 51 is connected to the degassing chamber 50. Reference numeral 55 denotes a sealing processing chamber, which is connected to the glove box 40 via a second partition 43 provided so as to be openable and closable.
Exhaust means 56 for exhausting the air in the chamber 5, a sealing processing chamber 55
Inside, a gas supply means 57 for supplying a rare gas sealed in the arc tube 10 is connected. Then, using such a glove box device, the ceramic discharge lamp having the configuration shown in FIG. 1 is manufactured through the following steps (A) and (B).

[Step (A)] This step (A) is a step of degassing by heating the arc tube material, the electrode mount, the sealing material and the necessary solid luminescent material. First, as shown in FIG. 3, an arc tube material 10a having sealing tube portions 12 formed at both ends of a discharge space surrounding portion 11 (FIG. 3 (a)).
), An electrode mount 20 composed of an electrode 21, a sleeve member 22 and a lead member 23 (shown in FIG. 3 (b)), and a ring-shaped electrode having an inner diameter matching the outer diameter of the lead member 23 in the electrode mount 20. Sealing material 30a
(Shown in FIG. 3 (c)), and a necessary solid luminescent material is prepared. In the degassing chamber 50 depressurized by the vacuum pump 51, light is emitted by an appropriate degassing heating means. Each of the tube material 10a, the electrode mount 20, the sealing material 30a, and the solid luminescent material is degassed by heating under reduced pressure. Hereinafter, specific conditions for the degassing of the arc tube material 10a, the electrode mount 20, the sealing material 30a, and the solid luminescent material will be described.

[Preliminary degassing treatment of arc tube material] Arc tube material 1
As Oa, it is preferable to use a gas from which the gas existing inside the material forming the arc tube material 10a has been removed by performing a preliminary degassing process. Arc tube material 10
The preliminary degassing treatment a is preferably performed in an environment at a pressure of 1 × 10 ⁻³ Pa or less. When the preliminary degassing treatment is performed in an environment having a pressure exceeding 1 × 10 ⁻³ Pa, the material (eg, tungsten, tantalum, molybdenum, etc.) constituting the heating heater used for the preliminary degassing treatment, and its oxide Alternatively, the arc tube material 10a may be contaminated by carbide or oil from the vacuum exhaust device adhering to the arc tube member 10a.

When the arc tube material 10a is made of translucent polycrystalline alumina, the heating temperature in the preliminary degassing treatment is preferably 1100 to 1500 ° C., and the heating time is 30 to 120 minutes. It is preferred that If the heating temperature is lower than 1100 ° C., it takes a considerably long time to perform a sufficient degassing treatment, and the time efficiency in the preliminary degassing treatment is undesirably reduced. On the other hand, when the heating temperature exceeds 1500 ° C., the light transmittance of the ceramic constituting the arc tube material 10a may be reduced. If the heating time is less than 30 minutes, sufficient preliminary degassing may not be performed. On the other hand, when the heating time exceeds 120 minutes, the temporal efficiency in the preliminary degassing treatment is reduced, which is not preferable.

For the same reason as above, when the arc tube material 10a is made of a translucent yttrium-aluminum-garnet polycrystal, the heating temperature in the preliminary degassing process is 1000-1400 ° C. The heating time is preferably 30 to 120 minutes. Further, when the arc tube material 10a is made of a translucent polycrystalline yttria, the heating temperature in the degassing treatment is preferably 1300 to 1500 ° C, and the heating time is 30 to 120 minutes. Is preferred.

[Degassing of Arc Tube] The degassing process of the arc tube material 10a is performed by heating at a temperature of 800 ° C. or more for 15 to 120 minutes in an environment of a pressure of 1 × 10 ⁻³ Pa or less. Is preferred. When degassing is performed in an environment at a pressure exceeding 1 × 10 ⁻³ Pa, the material constituting the heating heater used for the degassing process, its oxides or carbides, and the oil content from the vacuum exhaust device are reduced. By adhering to the arc tube 10a, the arc tube 10a may be contaminated. If the heating temperature is lower than 800 ° C., the impurity gas adsorbed on the surface of the arc tube material 10a cannot be sufficiently removed. Heating time is 1
If the time is less than 5 minutes, sufficient degassing may not be performed. On the other hand, when the heating time exceeds 120 minutes, the temporal efficiency in the preliminary degassing treatment is reduced, which is not preferable. Further, in the degassing treatment of the arc tube material 10a, the water molecules and other impurity gas molecules that have been adsorbed can be released by irradiating the arc tube material 10a with ultraviolet rays. Such a method is effective when both the degassing processes are performed simultaneously with the electrode mount 20 disposed in the arc tube material 10a because the arc tube material 10a has translucency.

[Degassing of Electrode Mount] Degassing of the electrode mount 20 is performed at a temperature of 800 to 1100 ° C. and a temperature of 15 to 12 under an environment of a pressure of 1 × 10 ⁻³ Pa or less.
It is preferable to carry out by heating for 0 minutes. 1x1
When degassing is performed in an environment having a pressure exceeding 0 ^-3 Pa, niobium forming the inner portion 23a of the lead member 23 may be oxidized to a degree that cannot be ignored. Further, a material constituting the heating heater used for the degassing process, its oxide or carbide may adhere to the electrode mount 20. Heating temperature is 800
If the temperature is lower than the temperature, the impurity gas adsorbed on the surface of the electrode mount 20 cannot be sufficiently removed. on the other hand,
When the heating temperature exceeds 1100 ° C., the lead member 2
3 may be deteriorated. Also,
If the heating time is less than 15 minutes, sufficient degassing may not be performed. On the other hand, the heating time is 120
If the time is longer than minutes, the time efficiency in the degassing treatment is lowered, which is not preferable.

[Degassing treatment of sealing material] Sealing material 3
0a degassing treatment is performed at a temperature of 1000 to 1200 ° C. or higher in an environment of a pressure of 1 × 10 ⁻³ Pa or lower and a temperature of 15 to 1
Preferably, the heating is performed by heating for 20 minutes. 1x
When degassing is performed in an environment having a pressure exceeding 10 ⁻³ Pa, the material constituting the heating heater used for degassing, its oxides or carbides, and oil from the vacuum exhaust device are sealed. By adhering to the wearing material 30a, the sealing material 30a may be contaminated. If the heating temperature is lower than 1000 ° C., it takes a considerably long time to perform a sufficient degassing process, and the time efficiency in the degassing process is undesirably reduced. On the other hand, when the heating temperature exceeds 1200 ° C., the sintering of the sealing material proceeds, so that it may be difficult to sufficiently perform the degassing treatment of the sealing material in the step (B) described below. is there. If the heating time is shorter than 15 minutes, sufficient degassing may not be performed.
On the other hand, when the heating time is longer than 120 minutes, the time efficiency in the degassing treatment is reduced, which is not preferable.

[Degassing treatment of solid luminescent material] When the solid luminescent material is a metal halide, the degassing treatment of the solid luminescent material is performed under an environment of a pressure of 1 × 10 ⁻³ Pa or less. Saturated vapor pressure of metal halide is 1 × 10 ^-3
It is preferable to perform the heating by heating at a temperature of about 1 × 10 ⁻⁵ Pa or a temperature of 350 ° C. or less for 15 to 120 minutes. In the case where degassing is performed in an environment having a pressure exceeding 1 × 10 ⁻³ , the solid luminescent material may be contaminated by the oil from the vacuum exhaust device adhering to the solid luminescent material. If the heating temperature is lower than the temperature at which the saturated vapor pressure of the metal halide becomes 1 × 10 ⁻⁵ Pa, sufficient degassing treatment may not be performed. On the other hand, when the heating temperature is such that the saturation vapor pressure of the metal halide is 1 × 1
If the temperature exceeds 0 ^-3 Pa or exceeds 350 ° C.,
It is not preferable because the evaporation of the metal halide becomes remarkable and the contained water is oxidized. If the heating time is shorter than 15 minutes, sufficient degassing may not be performed. On the other hand, when the heating time is longer than 120 minutes, the time efficiency in the degassing treatment is reduced, which is not preferable.

[Step (B)] In this step (B), the luminous tube material 10a, the electrode mount 20, the sealing material 30a and the solid luminescent material, which have been degassed in the above step (A), respectively, in a low humidity atmosphere. Is carried in a low-humidity atmosphere without being exposed to the atmosphere, and the arc tube material 10a, the electrode mount 20, and the sealing material 30a are assembled and sealed in the low-humidity atmosphere. Specifically, each of the degassed arc tube material 10a, the electrode mount 20, the sealing material 30a, and the solid light emitting substance is
It is carried into the glove box 40 in a low humidity atmosphere from the degassing chamber 50, and in the glove box 40, as shown in FIG. 4A, with one end of the arc tube material 10a facing upward. The electrode mount 20 is inserted from one end of the arc tube material 10a, and the power supply mount 20 is arranged so that the positioning projection 24 of the lead member 23 is in contact with one end surface of the sealing tube portion 12 of the arc tube material 10a. By holding the sealing material 30a on the holding flange 25 of the lead member 23, the arc tube material 10a, the electrode mount 20, and the sealing material 30a are formed.
Is made.

This assembly is carried from the glove box 40 into a sealing processing chamber 55 in the same low humidity atmosphere as in the glove box 40. In this sealing processing chamber 55, the sealing tube for the arc tube 10a is sealed. Part 12 and electrode mount 2
The sealing process with the 0 lead member 23 is performed. More specifically, the degassing process of the sealing material 30a is performed by heating the sealing material 30a by the heating device for sealing process while the pressure in the sealing process chamber 55 is reduced by the exhaust unit 56. As shown in FIG. 4B, the sealing material 30a is deformed into a substantially spherical shape by its surface tension. Thereafter, a rare gas is supplied into the sealing processing chamber 55 by the gas supply means 57, and the sealing material 30a is heated to the working point temperature or higher by the heating means for sealing processing, whereby the sealing is performed. Wear material 30a
Descends due to gravity and further enters the gap K between the sealing tube portion 12 of the arc tube material 10a and the lead member 23 of the electrode mount 20. At this time, it is preferable to heat the end portion of the arc tube material 10a so that the rare gas flows out from the end portion of the arc tube material 10a, and thereby, the impurity gas generated when the sealing material 30a is melted is discharged.
a can be prevented from being introduced. Then, the gap material K is filled in the gap K by increasing the gas pressure in the sealing processing chamber 55. By cooling the sealing material 30a in this state, as shown in FIG. 4C, the lead material 23 of the electrode mount 20 is attached to the sealing tube 12 of the arc tube material 10a by the sealing material 30a. Airtightly fixed.

After the solid luminous substance is placed in the arc tube 10a, the lead member 23 of the electrode mount 20 is fixed to the inner surface of the sealing tube 12 at the other end of the arc tube 10a in the same manner as described above. Thus, the ceramic discharge lamp having the configuration shown in FIG. 1 is manufactured.

In the present invention, the above step (B) comprises:
Arc tube material 10a, electrode mount 20, sealing material 30a
And the surface temperature of each of the solid luminescent materials is t (° C.),
The dew point of the low humidity atmosphere in the step (B) is dp
(° C.), the reaction is performed under the condition satisfying the following expression (1). Formula (1) t ≧ 2 × (100 + dp)

If the surface temperature t does not satisfy the above equation (1), the arc tube material 10a and the electrode mount 2
0, water molecules are re-adsorbed to the sealing material 30a or the solid luminescent material, and the resulting ceramic discharge lamp has problems such as an increase in starting voltage.

In the above step (B), the dew point dp of the low humidity atmosphere is preferably from -80 to -40 ° C. When the dew point dp is less than -80 ° C,
In order to maintain the dew point dp, it is necessary to use a gas purifier having a considerably high capacity, which undesirably increases the cost of a discharge lamp manufacturing facility. On the other hand, when the dew point dp exceeds −40 ° C., the amount of water contained in the atmosphere is large, so that it is difficult to suppress the amount of water molecules adsorbed on the arc tube material 10 a and the like. It is necessary to maintain the surface temperature t of each of the sealing material 30a and the solid luminescent material at a temperature higher than 125 ° C., and as a result, oxidation of the solid luminescent material by water molecules proceeds, which is not preferable.

In the above step (B), if the surface temperature t of the arc tube material 10a, the electrode mount 20, the sealing material 30a and the solid luminescent material satisfies the condition of the above equation (1), It is not necessary to maintain a constant temperature. That is, in the initial stage of the step (B), the surface temperature t of the arc tube material 10a, the electrode mount 20, the sealing material 30a and the solid luminescent material is, for example, 40 K or more higher than the lower limit of the temperature defined by the formula (1). , The arc tube material 10a, the electrode mount 20, the sealing material 30a, and the surface temperature t of the solid luminescent material are expressed by the formula (1).
The step (B) may be completed before the temperature falls to the lower limit of the temperature defined by According to such a method, there is no need to control the surface temperature of the arc tube material 10a, the electrode mount 20, the sealing material 30a, and the solid luminescent material, and there is no need to provide special equipment for temperature control. An increase in equipment cost can be avoided.

According to the above-described method for manufacturing a ceramic discharge lamp, the arc tube 10a, the electrode mount 20, the sealing material 30a, and the solid luminous substance are each degassed, and then, in a low humidity atmosphere, the arc tube 10a. In a state where the surface temperatures of the electrode mount 20, the sealing material 30a, and the solid luminescent material are maintained at specific temperatures in relation to the dew point of the low humidity atmosphere, the arc tube material 10a and the electrode mount 2 are maintained.
0 and the sealing material 30a are assembled.
a, the lead member 23 of the electrode mount 20 is fixed to the inner surface of the sealing tube portion 12 of the arc tube material 10a,
In order to enclose a solid luminescent substance inside the arc tube material 10a, the arc tube 10, the electrode mount 20, and the sealing material 30a
In addition, the amount of water molecules adsorbed on each of the solid light emitting substances can be suppressed to an extremely small value. As a result, the amount of water molecules present in the arc tube 10 is small and the ceramic discharge having the desired lamp characteristics is achieved. The lamp can be reliably manufactured.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described manufacturing method, and various modifications can be made. For example, the arc tube material, the electrode mount, and the sealing material are not limited to those shown in FIG. 3, and various structures can be used.
Further, the glove box device is not limited to the one shown in FIG. 2, and various configurations can be used. For example, the degassing chamber does not need to be connected to the glove box, and in the independently disposed degassing chamber, after degassing the arc tube and the like, these are placed in an appropriate closed container. You may store and carry in a glove box.

The present invention is not limited to a ceramic discharge lamp sealed at both ends, and it is also possible to manufacture a ceramic discharge lamp sealed at one end. FIG. 5 shows an example of a ceramic discharge lamp of the one end sealing type obtained by the manufacturing method of the present invention. In this ceramic discharge lamp, an arc tube 10 in which a sealing tube portion 12 is formed at one end of a substantially spherical discharge space surrounding portion 11 is provided. An electrode mount 20 having a pair of electrodes 21 arranged to face each other along a direction perpendicular to the tube axis is arranged. Each of the electrodes 21 of the electrode mount 20 is connected to the discharge tube surrounding portion 1 from the sealing tube portion 12 of the arc tube 10.
The rod-shaped internal lead members 26 are connected so as to be arranged along the tube axis direction toward each other, and a base end of each of these internal lead rods 26 has an inner diameter that matches the outer diameter of the internal lead rod 26. Sleeve member 22 having two through holes
Are fitted, and a rod-shaped external lead member 27 extending in the same direction as the internal lead member 26 is integrally provided at the base end of each of the internal lead members 26. The outer lead member 27 includes an inner portion 27a located inside the sealing tube portion 12 of the arc tube 10 and an outer portion 27b other than the inner portion 27a.
Are integrally connected by welding or the like, the inner portion 27a of the outer lead member 27 is formed of niobium, and the outer portion 27b of the outer lead member 27 is formed of an oxidation-resistant metal or alloy such as platinum. ing. Then, a portion including a connection portion between the inner portion 27a and the outer portion 27b of the external lead member 27 of the electrode mount 20 is hermetically sealed to the inner surface of the sealing tube portion 12 of the arc tube 10 by the sealing member 30. ing. According to the present invention, such a ceramic discharge lamp of one end sealing type can be manufactured according to the above-described method of manufacturing a ceramic discharge lamp of both ends sealing type.

[0033]

EXAMPLES The present invention will now be described by way of specific examples, which should not be construed as limiting the invention thereto.

Embodiment 1 FIG. 3 shows the condition according to the following conditions.
Use the arc tube material, electrode mount and sealing material
A solid luminescent material was prepared while preparing. [Emitting tube material (10a)] Material: Translucent polycrystalline alumina, outside discharge space surrounding part
Diameter: 5.0mm, inner volume of discharge space surrounding part: 0.05c
m^Three [Electrode mount (20)] Electrode (21): Tungsten, coil material; tongue
Stainless steel, sleeve member (22): made of polycrystalline alumina, lead member (23): material of inner part (23a);
Material of outer part (23b); 20% iridium-8
0% platinum alloy [Seal material (30a)] Material: Dy_TwoO_Three-Al_TwoO_Three-SiO_Two(Dy
_TwoO_Three: Al_TwoO_Three: SiO _TwoIs 61:17 by weight ratio
22) [Solid light-emitting substance] Mercury-cesium alloy: 1.0 mg,
0.3 mg of mercuric iodide, 10 mol of cesium iodide and iodine
3.6 mg of a mixture of 1 mol of gadolinium iodide

Step (A): In the degassing chamber of the glove box apparatus shown in FIG. 2, the above-mentioned arc tube material, electrode mount, sealing material and solid luminescent material (a mixture of cesium iodide and gadolinium iodide) are used. Degassing was performed under the following conditions. [Emitting tube material (10a)] Atmospheric pressure: 2 × 10 ⁻⁴ Pa, heating temperature 1000 ° C., heating time 120 minutes [Electrode mount (20)] Atmospheric pressure: 2 × 10 ⁻⁴ Pa, heating temperature 1000 ° C., heating time 120 minutes [Seal material (30a)] Atmospheric pressure: 2 × 10 ⁻⁴ Pa, heating temperature 1000 ° C., heating time 120 minutes [solid luminescent material] Atmospheric pressure: 1 × 10 ⁻⁴ Pa, heating temperature 350 ° C., heating Time 15 minutes

Step (B): The degassing-treated arc tube material, electrode mount, sealing material and solid luminescent material are placed in a glove box in an argon gas atmosphere with a dew point set at -70 ° C. And the arc tube material,
While maintaining the surface temperature of each of the electrode mount, the sealing material, and the solid luminescent material at 64 ° C., assembly was performed according to the configuration shown in FIG. After carrying this assembly into the sealing chamber in the same low humidity atmosphere as in the glove box,
By reducing the pressure in the sealing chamber by the exhaust means,
While performing the degassing process of the assembly, the sealing material is heated by the heating means for the sealing process until the sealing material is deformed into a substantially spherical shape by the surface tension, and then, by the gas supply means, into the sealing process chamber. While supplying the argon gas, the sealing material was heated to about 160
By heating to 0 ° C., the sealing material enters the gap between the sealing tube portion of the arc tube material and the lead member of the electrode mount, and further increases the gas pressure in the sealing chamber. The sealing material was filled in the gap. Then, in this state, the sealing material is cooled from the working point temperature to a temperature not higher than the strain point temperature (840 ° C.) in 40 seconds, so that the lead of the electrode mount is attached to the sealing tube portion of the arc tube material by the sealing material. The member was fixed.

After the solid luminous substance is placed in the arc tube material, the lead member of the electrode mount is fixed to the inner surface of the sealing tube at the other end of the arc tube material in the same manner as described above. A ceramic discharge lamp with a distance of 6 mm and an argon tube (filled pressure of 133 kPa) and a solid luminescent material sealed in the arc tube was manufactured. When these ceramic discharge lamps were turned on with high frequency power of about 20 kHz, the lamp current was 0.4 A, the lamp voltage was 50 V, and the lamp input was about 20 W.

<Examples 2 to 6 and Comparative Examples 1 and 2> In step (B), the dew point dp of the atmosphere in the glove box was set according to the following Table 1, and the arc tube material, electrode mount, sealing material, and solid A ceramic discharge lamp was manufactured in the same manner as in Example 1 except that the surface temperature t of each luminescent material was maintained at the temperature shown in Table 1 below.

[0039]

[Table 1]

The starting voltages of the ceramic discharge lamps obtained in Examples 1 to 7 and Comparative Examples 1 to 7 were measured. Table 2 shows the results.

[0041]

[Table 2]

As is clear from the results in Table 1, Example 1
Each of the discharge lamps according to Nos. 6 to 6 has a starting voltage of 600 V
On the other hand, the discharge lamps according to Comparative Examples 1 and 2 have a starting voltage of 800 V or more, and according to the manufacturing method of the present invention, a ceramic discharge lamp having a sufficiently low starting voltage can be obtained. It is understood that.

[0043]

According to the method for producing a ceramic discharge lamp of the present invention, after degassing each of the arc tube material and the sealing material, the surface temperature of the arc tube material and the electrode mount is reduced in a low humidity atmosphere. Assembling the arc tube material and the electrode mount while maintaining the specific temperature in relation to the dew point of the low humidity atmosphere, and fixing the electrode mount to the sealing tube portion of the arc tube material. The amount of water molecules adsorbed to each can be suppressed to an extremely small value, and as a result, the amount of water molecules present in the arc tube is small and a ceramic discharge lamp having the desired lamp characteristics can be reliably manufactured. Can be.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing a configuration of an example of a ceramic discharge lamp obtained by a manufacturing method of the present invention.

FIG. 2 is an explanatory view schematically showing the configuration of an example of a glove box device used in the manufacturing method of the present invention.

FIG. 3 is an explanatory view showing a configuration of an arc tube material, an electrode mount, and a sealing material used in the manufacturing method of the present invention.

FIG. 4 is an explanatory view showing an example of the steps of the manufacturing method of the present invention.

FIG. 5 is an explanatory sectional view showing the configuration of another example of a ceramic discharge lamp obtained by the manufacturing method of the present invention.

[Explanation of symbols]

 Reference Signs List 10 arc tube 10a arc tube material 11 discharge space surrounding portion 12 sealing tube portion 20 electrode mount 21 electrode 22 sleeve member 23 lead member 23a inner portion 23b outer portion 24 positioning protrusion 25 holding flange 26 internal lead member 27 external lead Member 27a Inner part 27b Outer part 30 Sealing member 30a Sealing material 40 Glove box 41 Working glove 42 First partition 43 Second partition 50 Degassing chamber 51 Vacuum pump 55 Sealing chamber 56 Exhaust means 57 Gas Supply means

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] June 2, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0034

[Correction method] Change

[Correction contents]

Example 1 According to the following conditions, FIG.
In addition to producing an arc tube material, an electrode mount, and a sealing material having the configurations shown in (1) and (2), a solid light emitting substance was prepared. [Emitting tube material (10a)] Material: translucent polycrystalline alumina, outer diameter of discharge space surrounding portion: 5.0 mm, inner volume of discharge space surrounding portion: 0.05c
m ³ [electrode mount (20)] Electrode (21): made of tungsten, material of coil; tungsten, sleeve member (22): made of polycrystalline alumina, lead member (23): material of inner part (23a); niobium, Material of outer portion (23b); platinum alloy [sealing material (30a)] Material: Dy ₂ O ₃ —Al ₂ O ₃ —SiO ₂ [solid luminescent material] Mercury-cesium alloy: 1.0 mg, mercury iodide 0 .3m
g, 3.6 mg of a mixture of 10 mol of cesium iodide and 1 mol of gadolinium iodide

Claims (3)

[Claims] 1. A method for manufacturing a ceramic discharge lamp comprising an arc tube made of a translucent ceramic, comprising: an arc tube made of a translucent ceramic having a sealing tube formed at an end. And degassing process by heating each of the electrode mounts under reduced pressure (A)
Disposing the degassed electrode mount in the degassed arc tube in a low humidity atmosphere, and fixing the electrode mount to the inner surface of the sealing tube portion of the arc tube (B). In the step (B), when the surface temperature of the arc tube material and the electrode mount is t (° C.) and the dew point of the low humidity atmosphere is dp (° C.), the following equation (1) is obtained. A method for producing a ceramic discharge lamp, characterized by satisfying. Formula (1) t ≧ 2 × (100 + dp) 2. The method for producing a ceramic discharge lamp according to claim 1, wherein the dew point of the low humidity atmosphere in the step (B) is -80 to -40 ° C. 3. In the initial stage of the step (B), the surface temperature of the arc tube material and the electrode mount is higher than the lower limit of the temperature defined by the formula (1), and the surface temperature of the arc tube material and the electrode mount is higher. 3. The method for manufacturing a ceramic discharge lamp according to claim 1, wherein the step (B) is completed before the temperature decreases to a lower limit value of the temperature defined by the equation (1).