JPH0836995A - Ceramic discharge lamp, lighting device for discharge lamp, and lighting system - Google Patents

Abstract

PURPOSE:To hold high color rendering performance, light emitting efficiency, and joint strength for a long time by optimaly regulating mix rate of crystal bodies of A12O3-CaO based glass solder by a peak ratio in X-ray crystal diffraction angle. CONSTITUTION:A discharge lamp comprises sealing bodies 3a, 3b to which electrodes 6 connected to the aperture end parts of a light emitting tube bulb 2 via Al2O3-CaO based glass solders 4a, 4b, 7a, 7b are attached and a light emitting material containing sodium and rate gas is sealed therein. Mixing rate of crystal bodies of CaO.Al2O3, 3CaO.Al2O3, and 12CaO.7Al2O3 of the glass solder is set to the second peak of 12CaO.7Al2O3/the first peak of CaO.Al2 O3<=0.2, or the second peak of 12CaO.7Al2O3/the second peak of 3CaO.Al2 O3<=0.2 in a peak ratio in X-ray fraction angle. Reaction with sodium can thus be prevented so as to provide stable life characteristics.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic discharge lamp in which a closed body is hermetically bonded to the open end of an arc tube made of translucent ceramic having excellent heat resistance and corrosion resistance by using a glass solder. .

[0002]

2. Description of the Related Art Ceramic discharge lamps such as high-pressure sodium lamps are made of translucent ceramics having excellent heat resistance and corrosion resistance, such as translucent alumina.
_A closing body (end cap) made of a ceramic such as ₂ O ₃ or a metal such as niobium Nb is airtightly joined and closed through a glass solder.

In the arc tube, an amalgam of sodium Na in excess of the amount evaporated during lighting and a starting rare gas such as neon Ne-argon Ar or xenon Xe are enclosed, and each of the above-mentioned each. Discharge electrodes are provided on the closing body so as to face each other in the arc tube.

Further, as a glass solder for airtightly bonding the above-mentioned closed body, Al ₂ O ₃ (alumina = aluminum oxide) -CaO (calcium oxide) system is required, and a higher adhesive force is required. Al ₂ O
_In order to approximate the coefficient of thermal expansion with ₃ (alumina) or Nb (niobium), the above Al ₂ O ₃ (alumina), CaO
Means such as adding BaO (barium oxide) to (calcium oxide) is also used.

In such a lamp, N
Although a (sodium) amalgam is evaporated and this is excited to emit light, the high color rendering high-pressure sodium lamp has a higher tube wall load than the general high-pressure sodium lamp and also has a higher Na (sodium) vapor pressure. In such a lamp, during the life of the lamp, the components of the glass solder react with Na (sodium),
Disappears, the vapor pressure of Na (sodium) decreases, the luminous efficiency and the color rendering deteriorate, and the color characteristics deteriorate and the adhesive strength decreases.

This is because a certain amount of Ca or more is contained in the glass solder.
When O (calcium oxide) is present, crystals of 12CaO.7Al ₂ O ₃ which is a compound of CaO (calcium oxide) and Al ₂ O ₃ (alumina) tend to be easily precipitated in the sealed portion after melting and cooling. Yes, this compound is high temperature N
This phenomenon occurs because the resistance to a (sodium) vapor is extremely low.

[0007]

Therefore, the inventors of the present invention have previously defined an Al ₂ O ₃ -CaO type glass solder capable of solving the above-mentioned problems by defining the crystal structure of Al ₂ O ₃ and CaO. It was proposed as JP-A-5-275065. Al ₂ having the crystal structure shown in this publication
A discharge lamp using O ₃ -CaO glass solder is N
The reaction with a (sodium) is reduced and good bonding strength is obtained.

In this type of high pressure discharge lamp, when an arc tube bulb made of quartz glass is used, the bulb end is directly heated by an oxyhydrogen gas burner or the like to melt and close the glass and seal the introduction conductor. Therefore, mass production is possible with an automatic sealing machine that can be operated intermittently or continuously at high speed.

However, an arc tube bulb made of translucent ceramics such as translucent alumina cannot be melted and has a structure in which a closing body is sealed at the opening end of the bulb through a glass solder. Therefore, the work of closing this valve opening end cannot be performed simply, and in mass production, several to several tens of them are manufactured at a time, compared to the case of using a quartz glass valve. It was a poor one.

According to the tests conducted by the present inventors, the Al ₂ O ₃ --CaO: type glass solder, which defines the crystal structure of the above publication, showed good results for simultaneous blockage up to 20 positions.
If a large number of plugs are closed at the same time to improve productivity, a reaction with Na (sodium) will appear in the sealing part during operation of the discharge lamp, and the loss of Na (sodium) cannot be suppressed and is stable. It was found that there is a problem in that the life characteristics described above cannot be obtained, and the light-tightness is not impaired, but the light color becomes “pink” and the color rendering is deteriorated. Therefore, it is necessary to improve the crystal structure.

The present invention has been made in view of the above circumstances, and improves the glass solder to prevent the reaction with Na (sodium) and suppress the disappearance of Na (sodium), thereby providing a high color rendering property and a higher color rendering property than conventional ones. It is another object of the present invention to provide a ceramic discharge lamp capable of realizing stable life characteristics.

[0012]

A ceramic discharge lamp according to claim 1 of the present invention is an arc tube bulb made of translucent ceramic, and a Ca at the opening end of the arc tube bulb.
O · Al ₂ O ₃ , 3CaO · Al ₂ O ₃ and 12Ca
Al ₂ O ₃ having a crystal structure of O · 7Al ₂ O ₃ -CaO
In a discharge lamp including a closed body formed by attaching electrodes bonded via a glass solder of a system, a luminous substance containing sodium and a rare gas sealed in the arc tube bulb, the glass solder is CaO. Al ₂ O ₃ , 3CaO
The mixing ratio of the crystals of Al ₂ O ₃ and 12CaO · 7Al ₂ O ₃ is the ratio of the peaks in the X-ray crystal diffraction angle, and the second peak of 12CaO · 7Al ₂ O ₃ / CaO · Al.
₂ O ₃ first peak ≦ 0.2, 12CaO · 7Al ₂ O ₃ second peak / 3CaO · A
The feature is that the second peak of l ₂ O ₃ ≦ 0.2.

The ceramic discharge lamp according to claim 2 of the present invention is characterized in that the closing body is made of ceramics.

The ceramic discharge lamp according to claim 3 of the present invention is characterized in that the closing body is made of a refractory metal such as niobium Nb, tantalum Ta, or molybdenum Mo. The ceramic discharge lamp according to claim 4 of the present invention is characterized by being a high-pressure sodium lamp or a metal halide lamp.

A lighting device for a discharge lamp according to a fifth aspect of the present invention is a lighting circuit, and the ceramic discharge lamp according to any one of the first to fourth aspects, which is connected to an output side of the lighting circuit. It is characterized by having.

A lighting fixture according to a sixth aspect of the present invention is provided with the ceramic discharge lamp according to any one of the first to fourth aspects, a reflecting mirror housing the lamp, and a front face of the reflecting mirror. It is characterized in that it is provided with a transparent body.

[0017]

According to the present invention, the mixing ratio of the crystals is regulated to the optimum combination, the reaction between the glass solder and sodium is prevented, the loss of sodium is reduced, and the high luminous efficiency is maintained for a long time. In addition, it is possible to prevent the problem that the light color is “pinked” and the color rendering is deteriorated, and at the same time, the bonding strength can be kept high.

[0018]

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a ceramic discharge lamp such as a high-pressure sodium lamp L, FIG. 1 is a front sectional view of the arc tube 1, and FIG. 2 is a front view of the high-pressure sodium lamp L as a whole. In the figure, 2 is an arc tube bulb made of a translucent ceramics tube such as polycrystalline alumina or single crystal alumina, 3
Reference characters a and 3b are closed bodies (end caps) made of polycrystalline alumina or single crystal alumina, which are formed by hermetically closing open end portions of both ends of the arc tube bulb 2 with glass solders 4a and 4b described later.

Niobium (Nb) is contained in the closures 3a and 3b.
Metal tubes 5a and 5b made of tantalum (Ta) or the like are penetrated and are airtightly joined to the closure plates 3a and 3b through the same glass solders 7a and 7b as described above. An electrode 6 is fixed to the inside of the metal tubes 5a and 5b by means of caulking 5d, welding or the like, and an outer end is airtightly closed (5c portion). The electrodes 6, tungsten (W) tungsten tip of the electrode rod 6a consisting of (W) wire electrode coil 6b formed of the wound, this electrode coil 6b, for example, such as BaO-CaO-WO ₃ An electron emissive material (emitter) (not shown) is applied. Further, a predetermined amount of sodium (Na) amalgam as a light emitting substance and a rare gas such as neon Ne, argon Ar, or xenon Xe as a starting gas are sealed in the bulb 2 at a predetermined pressure.

The metal pipes 5a and 5b are caulked 5
The electrode 6 fixed by means such as d or welding is not in contact with the entire surface of the circumferential part but in partial contact, and has a partial gap so as not to hinder the exhaust of the valve 2 or the passage of the inclusions. There is.

The glass solder 3a, 3b for closing the open end of the arc tube bulb 2 has, for example, the main component A.
It is composed of 1 ₂ O ₃ and CaO, to which Y ₂ O ₃ (yttrium oxide) and SrO (strontium oxide) are added. And CaO (calcium oxide) A
l ₂ O ₃ (alumina = aluminum oxide) (hereinafter, CA
Called. ) 3CaO · Al ₂ O ₃ (hereinafter, referred to as 3CA) and 12CaO · 7Al ₂ O ₃ (hereinafter, 1)
2C7A. ), And the mixing ratio of these crystals is the ratio of the peaks at the X-ray crystal diffraction angle, which is the second peak of 12CaO · 7Al ₂ O ₃ / CaO · Al.
₂ O ₃ first peak ≦ 0.2, 12CaO · 7Al ₂ O ₃ second peak / 3CaO · A
The second peak of l ₂ O ₃ is ≦ 0.2. (Note that the X-ray crystal diffraction angle expressed in this specification was measured using an X-ray source of Cu, K _α1 .)

In general, such an arc tube 1 is enclosed in an outer bulb 11 to form a lamp L as shown in FIG. The arc tube 1 is sealed in a frame shape in which metal tubes 5a and 5b protruding from both ends are fixed to one of the lead wires 13a and 13b of the stem 12 which is sealed at one end of the outer bulb 11, for example, the lead wire 13a. It is attached to the support 14 of the. More specifically, the metal tube 5b on the lower side of the arc tube 1 is fixed via the heat-resistant and electrically insulating insulator 15 made of alumina or the like fixed to the lower side of the frame-shaped support 14, and the metal tube 5a on the upper side. Is attached to the support 14 by being fixed to a band 16 made of a metal plate by means such as welding or pressing. The electrical connection is such that the metal tube 5a on the upper side of the arc tube 1 passes through the lead wire 13a, the support 14 and the band 16, and the metal tube 5b on the lower side.
Is electrically connected from the lead wire 13b through the conductive foil or the conductive wire 17.

The inside of the outer tube valve 11 is filled with an inert gas such as argon Ar or nitrogen N or is evacuated. Further, in the figure, reference numeral 18 is a ferrule attached to the sealing portion of the outer tube 11, and 19 is a getter.

Next, a method of manufacturing the arc tube 1 will be described with reference to FIGS. 3 and 4. FIG. 3 shows a mass production apparatus for exhausting and sealing the arc tube bulb 2 and the closing body 3a. In the figure, 20 is an airtight container, inside of which a plurality of to several hundreds for holding the arc tube bulb 2 are held. For example, in multiple circles 1
A holder 22 having 00 recesses 21, 21, ... And a cylindrical heater 23 are provided. Also, the holder 2
A cooling liquid flow pipe 24 is embedded in the inside of 2. Further, on the side surface of the container 20, an exhaust pipe 25 connected to a vacuum pump via an open / close valve 25a, and an air supply pipe 2 connected to a rare gas such as an Ar gas cylinder via an open / close valve 26a.
6 is connected.

In the operation of this apparatus, first, the closing body 3b and the metal tube 5b are attached to the glass solder 4 at one opening.
It is sealed airtightly via b and 7b. Next, the sealing portion of the valve 2 on the side of the one closed body 3b, which has already been sealed, is put in the recesses 21, 21, ... Of the holder 22 and held. Next, the glass solder 4a, which has been molded into a ring shape, and the closing body 3a are placed on the other opening of the bulb 2 in an overlapping manner, and the metal tube 5a is held through the through hole in the central portion of the closing body 3a (holding device). Is not shown in the figure), and the glass solder 7a molded in the ring shape is placed thereon in the same manner as described above to obtain the state shown in FIG. Although not shown, the recess 2 of the holder 22 is usually used.
The arc tube bulbs 2, 2, ... Are mounted to the vessels 1, 21, ... With a structure in which the upper side and the lateral side of the container 1 can be freely opened and closed to facilitate the work.

Next, the flow pipe 24 of the holder 22 described above.
While opening the cooling liquid, open the on-off valve 25a to open the container 20.
Exhaust the inside. By this exhaust, arc tube bulbs 2, 2,
The interior is also exhausted through the gaps 8a and 8b.

Next, when the inside of the container 20 reaches a predetermined vacuum degree, the heater 23 is energized to generate heat, so that each arc tube bulb 2,
The vicinity of the opening above 2, ... Is heated, and the glass solder 4a formed in the opening and molded in a ring shape,
7a is melted to form a gap 8 between the end of the valve 2 and the closing body 3a.
a and the gap 8b between the closing body 3a and the metal pipe 5a, and permeates down. If the power supply to the heater 23 is stopped, the solder 4
a, 7a are cooled and solidified to form arc tube bulbs 2, 2, ...
All the openings above the are uniformly and airtightly closed.

In addition, at the time of the above-mentioned blockage, each arc tube bulb 2,
The holding tool 22 holding 2, ... Is carried out while the side that has been previously closed is cooled by the flow pipe 24.

Next, a predetermined amount of sodium (Na) amalgam is introduced into the valve 2 through the opening of the upper metal tube 5a, and then the metal tube 5a is pressure-contacted and sealed (5c part). The addition of this sodium (Na) amalgam is carried out in an inert gas in order to prevent alteration of the sodium (Na) amalgam. Then, a starting rare gas such as argon Ar-neon Ne is sealed in the valve 2 at a predetermined pressure from the opening of the metal pipe 5b on the lower side, and the metal pipe 5b is pressure-contact sealed (5c).
Part).

In the arc tube 1 manufactured in this manner, the metal tubes 5a and 5b protruding from both ends are locked to the insulator 15 of the frame-shaped support 14 fixed to the stem 12 and made of metal plate. It is clamped and attached by the band 16 and the stem 12 is sealed at one end of the outer bulb 11 to complete the high pressure sodium lamp L.

In the arc tube 1 having such a structure, as described above, the glass solders 4a, 4b and 7a, 7b for closing the open end of the arc tube bulb 2 are mainly composed of Al ₂ O ₃ ,
Consists of CaO, and CaO (calcium oxide)
Al ₂ O ₃ (alumina = aluminum oxide) (hereinafter, C
Called A. ) 3CaO ・ Al ₂ O ₃ (hereinafter 3CA
Called. ) And 12CaO.7Al ₂ O ₃ (hereinafter,
12C7A. ), And the mixing ratio of these crystals is the ratio of the peaks at the X-ray crystal diffraction angle, which is the second peak of 12CaO · 7Al ₂ O ₃ / CaO · Al.
₂ O ₃ first peak ≦ 0.2, 12CaO · 7Al ₂ O ₃ second peak / 3CaO · A
The second peak of l ₂ O ₃ is ≦ 0.2.

In the above, the second peak of 12C7A has a lattice spacing d of 4.89 Å,
The first peak of CA has a lattice spacing d of 2.97 angstroms, and the second peak of 3CA has a lattice spacing d of 1.91 angstroms.

The mixing ratio of the above composition is based on an experiment by the present inventors, which will be described below.

In the experiment, for example, in a high pressure sodium lamp rated at 150 W, a length of about 60 mm, an inner diameter of about 8 mm,
Sodium amalgam (Na 28.9% by weight) is placed inside the arc tube bulb 2 having a wall thickness of about 0.75 mm and an electrode distance of about 33 mm.
-Hg 71.1% by weight) 28 mg and a mixed gas of argon and neon as a starting gas (Ar 99.5% -Ne)
0.5%) was sealed to manufacture the arc tube 1. In addition, the main component of the joining of the closing bodies 3a and 3b that closes the opening end is A
A glass solder composed of 1 ₂ O ₃ and CaO, to which a small amount of Y ₂ O ₃ (yttrium oxide) and SrO (strontium oxide) was added was used.

The glass solders 3a and 3b are made of Al ₂ O.
₃ (alumina) and CaO (calcium oxide) as main components, and Y ₂ O ₃ (yttrium oxide) and SrO
It can be obtained by adding a small amount of (strontium oxide), mixing and kneading, and then firing at a temperature of 1000 ° C. or higher.

The glass solder that has undergone this firing step is
A measurement with a line diffractometer reveals that crystals having Al ₂ O ₃ and CaO as main components are formed. This crystal is CA (CaO.Al ₂ O ₃ ) 3CA described above.
(3CaO ・ Al ₂ O ₃ ) and 12C7A (12Ca
O.7Al ₂ O ₃ ).

Therefore, when examining the mixing ratio of these crystals, the composition ratio of this seed crystal is most appropriately measured by the X-ray crystal diffraction measuring method. The distance d was examined. The lattice spacing d of these crystals is well known because it is described in various documents and is shown in Table 1 below.

[0038]

[Table 1] With the lattice plane spacing d shown in Table 1 above, the wavelength λ is 1.540.
Table 2 shows the scattering angle (2θ) when irradiated with 51 angstrom X-rays.

The conversion formula is obtained by d = λ / 2sin θ θ = sin θ ⁻¹ (λ / 2d).

[0040]

[Table 2] Then, when the diffraction intensity with respect to the X-ray scattering angle (2θ) is measured, the diffraction characteristic as shown in FIG. 5, for example, is obtained.

The X-ray scattering angle (2θ) corresponding to each peak value in the characteristic of FIG. 5 is the scattering angle (2θ) shown in Table 2 above.
That is, the peak value existing around 2θ = 18 can be read from Table 2 above as being equivalent to the second peak of 12C7A. Similarly, 2θ = 30 in FIG.
It can be read from the above Table 2 that the peak values existing before and after correspond to the first peak of CA, and that the peak values existing before and after 2θ = 47 in FIG. 5 correspond to the second peak of CA above Table 2 to 3 CA. be able to.

Here, the peak value existing around 2θ = 33 in the characteristic of FIG. 5 is the first value of 12C7A from Table 2 above.
Corresponds to the peak and the first peak of 3CA, which appear overlapping. Therefore, the peak values occurring around 2θ = 33 cannot be read separately for 12C7A and 3CA. Therefore, 12C7A uses the second peak (lattice spacing d is 4.89 angstroms), and 3CA also uses the second peak (lattice spacing d is 1.91 angstroms). The respective crystal bodies CA, 3CA and 12C7A as described above are different from each other in terms of performance such as melting point, hygroscopicity and reactivity with sodium.

Therefore, the glass solder in which these different crystal bodies are mixed is the crystal bodies CA, 3CA and 1
Various properties such as melting point, hygroscopicity, and reactivity with sodium are different depending on the mixing ratio of 2C7A, and it is expected that the arc tube hermetically joined by such a glass solder has a different influence degree of the solder.

The crystal compositions CA, 3CA, and 12C7A differ in composition ratio when the firing temperature is changed, and the crystal composition ratios at the X-ray diffraction angle as shown in FIG. It can be known by examining the strength.

That is, when the firing temperature is changed, the crystal C
The crystal composition ratio of A, 3CA and 12C7A has changed,
Therefore, the peak ratio of the X-ray diffraction angle changes.

Therefore, the present inventors have found that Al ₂ O ₃ --CaO
A glass solder having different X-ray diffraction angle peak ratios was produced by changing the firing temperature of the glass solder of the system, and its crystal state and characteristics when used in the above lamp were examined. As a result, the crystal growth state at the Al ₂ O ₃ interface was CA, 3C.
It was confirmed that they differ depending on the peak ratio of the X-ray diffraction angles of A and 12C7A.

The experiment was carried out by using the above-mentioned apparatus, one arc tube 1 at a time of the same high pressure sodium lamp having the same rating of 150 W as described above.
00 pieces were produced. This arc tube 1 has a length of about 60 mm, an inner diameter of about 8 mm, a wall thickness of about 0.75 mm, and a distance between electrodes of about 33 mm.
Sodium amalgam (Na2
8.9 wt% -Hg 71.1 wt%) 28 mg and a mixed gas of argon and neon as a starting gas (Ar9
9.5% -Ne0.5%) was enclosed to manufacture the arc tube 1. Further, the joining of the closing plate 3 for closing the open end is made of Al ₂ O ₃ and CaO as main components, and a small amount of Y ₂ O is added to this.
_A glass solder prepared by adding ₃ (yttrium oxide) and SrO (strontium oxide) was used.

The mixing ratio of the glass solder crystals is such that the ratio of the peaks at the X-ray crystal diffraction angle is 12CaO.7Al ₂ O ₃ second peak / CaO.Al.
₂ O ₃ first peak ≦ 0.2, 12CaO · 7Al ₂ O ₃ second peak / 3CaO · A
a second peak of l ₂ O ₃ ≦ 0.2 within the specified range of the present invention, and a second peak of 12CaO · 7Al ₂ O ₃ / CaO · Al.
₂ O ₃ first peak> 0.2, 12CaO · 7Al ₂ O ₃ second peak / 3CaO · A
Comparison was made with lamps outside the specified range of the invention with a second peak of l ₂ O ₃ > 0.2.

In the test, the lamp was blinked for 30 minutes on and 30 minutes off for 2000 times under the overload condition of 150% of the rated value.
The state of sodium invasion of the glass solder in the closed part (sealed part) was examined.

The lamp in the range of the present invention showed no abnormality after 1000 times, and even after 2000 times, sodium infiltration was not found in the glass solder at the closed portion, and the light color did not change from the initial state.

On the other hand, in the lamp out of the specified range of the present invention, sodium intrusion was recognized in the glass solder at the closed portion (sealing portion) at 1000 times, and the light color changed to "pink" at 2000 times. There were some changes coming.

This is because 12CaO.7Al ₂ O ₃ is H ₂ O.
Has a strong affinity and is released at the moment the glass solder melts, and O ₂ is emitted at the time of crystallization.
As a result, it is presumed that the effect of O ₂ facilitates the invasion of sodium into the closed portion during the operation of the lamp.

Even when it is out of the specified range of the present invention, if the number of arc tubes that are closed (sealed) at one time is about 20, the amount of released O ₂ is small, and there is no problem. However, in consideration of variations and the like, problems do not occur within the scope of the present invention.

The above-mentioned high-pressure sodium lamp is used by being connected to the output side of a lighting circuit using a usual choke coil, transformer or the like.

Further, in the present invention, the mixing ratio of the crystal bodies of the glass solder is the ratio of the peaks in the X-ray crystal diffraction angle, which is the second peak of 12CaO · 7Al ₂ O ₃ / CaO · Al.
₂ O ₃ first peak ≦ 0.1, 12CaO · 7Al ₂ O ₃ second peak / 3CaO · A
In the lamp having the second peak of l ₂ O ₃ in the range of 0.1 or less, no problem occurred regardless of the number of processed lamps, and good results were obtained.

The high-pressure sodium lamp L shown in FIG. 2 is mounted as a lighting fixture, for example, on a lamp T shown in FIG. The lamp T is installed at a high place such as a pole, and a reflector 3 including a reflecting mirror is provided in the housing 30.
1 is formed, and a glass window 32 is provided on the front side as a light control body. Further, a socket 33 is provided in a portion formed by boring a part of the reflector 31, and the base 18 of the lamp L is attached to the socket 33.
Then, the lamp L is turned on through a lighting circuit device installed in the lamp T or a pole, and the direct light from the lamp L and the reflected light from the reflector 31 are emitted through the glass window 32.

The present invention is not limited to the above embodiment. For example, the glass solder is Al ₂ O ₃ -CaO-Y
I mentioned the mixture of ₂ O ₃ -SrO.
BaO (barium oxide) in Al ₂ O ₃ -CaO, MgO
It may be one to which (magnesium oxide) or the like is added, that is, any glass solder containing Al ₂ O ₃ —CaO as a main component may be used.

Further, the closing body for closing the opening end of the arc tube bulb is not limited to the one made of an insulating material made of ceramics, and conductive ceramics such as Nb (niobium), Ta (tantalum), A high melting point metal such as molybdenum (Mo) may be joined by the glass solder. Also, in the case of directly joining the closing body or the electrode rod made of conductive ceramics to the closing body,
The enclosure may be directly introduced into the bulb of the arc tube without providing the metal tube.

The discharge lamp is not limited to the high pressure sodium lamp, but can be applied to a metal halide lamp in which Na (sodium) is enclosed as a light emitting substance.

[0060]

As described in detail above, according to the present invention, X
Al ₂ O depending on the peak ratio due to the crystal diffraction angle of the line
_{3 Since} the mixing ratio of the crystals with (alumina) -CaO (calcium oxide) type glass solder was regulated to the optimum ratio, not only a small amount in the airtight container but also a large amount of arc tube ends at one time (sealing) work This blockage (sealing)
It is possible to reduce the influence of crystal water, which is an obstacle to the part. Therefore, the reaction of sodium in the arc tube can be suppressed to prevent the disappearance of sodium, the light color does not become “pink” with the progress of lighting, and high color rendering properties and high luminous efficiency are maintained for a long time. be able to. In addition, it is possible to provide a discharge lamp having various advantages such as improved wettability with the bulb structure and improved bonding strength.

[Brief description of drawings]

FIG. 1 is a front sectional view of an arc tube of a high-pressure sodium lamp showing an embodiment of the present invention.

FIG. 2 is a front view of a high pressure sodium lamp showing an embodiment of the present invention.

FIG. 3 is a schematic vertical cross-sectional view of an arc tube manufacturing apparatus showing an embodiment of the present invention.

FIG. 4 is a cross-sectional view before closing (sealing) one end portion for explaining a method of manufacturing an arc tube.

FIG. 5 is a characteristic diagram illustrating the relationship between the X-ray scattering angle and the diffraction intensity.

FIG. 6 is a perspective view of a lighting fixture showing an embodiment of the present invention.

[Explanation of symbols]

 L: high pressure sodium lamp 1: arc tube 2: arc tube bulb 3a, 3b: blocker 4a, 4b: glass solder 5a, 5b: metal tube 6: electrodes 7a, 7b: glass solder 8a, 8b: gap T: lighting fixture (Lamp)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takayuki Aoki 4-3-1, Higashishinagawa, Shinagawa-ku, Tokyo Toshiba Litec Co., Ltd.

Claims (6)

[Claims] 1. An arc tube bulb made of translucent ceramic; CaO.Al ₂ O at the open end of the arc tube bulb.
₃ , 3CaO · Al ₂ O ₃ and 12CaO · 7Al ₂
O ₃ of formed by attaching the bonded electrodes through the glass solder of Al ₂ O ₃ -CaO system having a crystal structure closure and; a light emitting material and a rare gas containing sodium encapsulated in the arc tube bulb ; in the discharge lamp having the above glass solder is _{CaO · Al 2 O 3, 3CaO} · Al 2 O
The mixing ratio of the crystals of ₃ and 12CaO.7Al ₂ O ₃ is the ratio of the peaks in the X-ray crystal diffraction angle, and the second peak of 12CaO · 7Al ₂ O ₃ / CaO · Al.
₂ O ₃ first peak ≦ 0.2, 12CaO · 7Al ₂ O ₃ second peak / 3CaO · A
A ceramic discharge lamp characterized in that the second peak of l ₂ O ₃ ≦ 0.2. 2. The ceramic discharge lamp according to claim 1, wherein the closing body is made of ceramics. 3. The closing body is made of niobium Nb or tantalum T
The ceramic discharge lamp according to claim 1, which is made of a refractory metal such as a or molybdenum Mo. 4. The ceramic discharge lamp according to claim 1, wherein the discharge lamp is a high pressure sodium lamp or a metal halide lamp. 5. A lighting of a discharge lamp, comprising: a lighting circuit; and the ceramic discharge lamp according to claim 1, which is connected to an output side of the lighting circuit. apparatus. 6. A ceramic discharge lamp according to any one of claims 1 to 4, a reflecting mirror accommodating the lamp, and a translucent body provided in front of the reflecting mirror. Lighting equipment characterized by the above.