JPH09237607A - Ceramic discharge lamp, lighting device, luminaire, and lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the mechanical strength of both end sections in the axial direction of an airtight container by increasing the diameters of both end sections in the axial direction of the airtight container, and forming a thick section on the outer peripheral section of a plug body connected to the opening end of a tube body. SOLUTION: A thick section 15b is integrally formed on the inner end face of the outer peripheral section of an end plug 15 to increase mechanical strength. The thickness (h) of the thick section 15b is made the maximum on the outer peripheral surface side of the end plug 15 connected to the inner peripheral face of the opening end of a bulb main body 13, and a downward slant face gradually reduced in thickness toward an insertion hole 15a for an electricity guide body is formed. The protrusion length L protruded to the insertion hole 15a side from the outer peripheral face of the thick section 15b is set to satisfy the equation, and excess sodium is separated from the glass solder 17. In the equation, D is the outer diameter of the end plug 15, and (d) is the inner diameter of the insertion hole 15 a for an electricity guide body.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a ceramics discharge lamp such as a high-pressure sodium lamp, a lighting device, a lighting fixture, and a lighting device.

[0002]

2. Description of the Related Art Conventionally, as a high-pressure sodium lamp of this type, Japanese Patent Application Laid-Open No. 57-98969 (hereinafter referred to as Prior Art 1
JP-A-57-84558 (hereinafter referred to as prior art 2), JP-A-1-143137 (hereinafter referred to as prior art 3), and JP-A-53-144277 (hereinafter referred to as prior art 4). Some of them are described in each publication.

FIG. 9 shows a general structure common to these conventional high-pressure sodium lamps, which is a tube 2 made of a translucent alumina ceramic and both ends of its axial opening are hermetically sealed. A monolithic tube (semi-closed tube), which is an airtight container formed by integrally sintering with an annular plug body 3 to be used, is used, and an electrode is provided at the tip portion in the insertion hole 4 for the electric introduction body of the plug body 3. The electric introduction body 6 provided with 5 is inserted and the sealing material 7 is filled and fixed. A starting gas and an excessive amount of sodium amalgam 9 are enclosed in the monolithic tube to form the arc tube 8. The sodium amalgam 9 accumulates at the corners on the inner surface of the end of the arc tube 8. However, in this type of high-pressure sodium lamp 1, excess sodium amalgam 9 comes into contact with the sealing material 7 and disappears. Since it is suppressed, it has stable life characteristics and is widely used in the market.

[0004]

However, in the high-pressure sodium lamp 1 of this type, the thermal stress strain due to the thermal shock due to the repeated high temperature state when the lamp is turned on and the low temperature state when the lamp is turned off increases due to the increase of the thermal stress strain of the tube 2. In some cases, a crack 10 may be generated at the joint with the plug body 3 and the airtightness of the arc tube 8 may be reduced, resulting in no lighting.

As a countermeasure against this, in the prior art 1, the outer peripheral surfaces of both ends in the axial direction of the pipe 2 are formed with thick portions which are thickened outward in the diametrical direction. Since the diameter projects outward, this pipe 2 cannot be pulled out in the axial direction by the cutting die. For this reason, the monolithic tube cannot be molded, which makes mass production difficult. Moreover, the prior art 2 is not so effective as to be put to practical use. Prior art 3 considers suppressing the loss of sodium by the sealing material 7 during the life of the lamp as much as possible.

In the prior art 4, the inner corner of the end portion of the arc tube 8 is formed so as to protrude from the sealing portion of the electric introducing member 6 toward the inside of the tube. In this case, excessive sodium amalgam comes into contact with the sealing material. Therefore, there is a problem that sodium disappears significantly due to the sealing material 7 during the life and the life characteristics are unstable.

Therefore, an object of the present invention is to form a thick-walled portion of the plug that projects inwardly of the airtight container in the plug, and the thickened portion L extends to the electric introduction body insertion hole side. By controlling the temperature within the specified range, sodium loss due to contact between sodium and sealing during the lamp life is suppressed as much as possible, and the strength of both axial ends of the airtight container is enhanced, and cracks occur during the lamp life. It is an object of the present invention to provide a ceramics discharge lamp, a lighting device, a lighting fixture, and a lighting device that can prevent the occurrence of light.

[0008]

A ceramic discharge lamp according to claim 1 of the present application comprises a cylindrical body made of translucent ceramic,
A translucent alumina ceramics plug body integrally formed at both open ends of the cylindrical body and having insertion holes for inserting and sealing the electric introduction body, and both axial end portions. An airtight container having a diameter larger than that of the middle part of the cylindrical body; a discharge medium containing excess sodium that is sealed in the end of the airtight container; and a pair that causes an electric discharge in the airtight container. Electrode on the inner end surface side of the outer peripheral portion of each plug body, and is integrally projected so as to project inward of the airtight container to increase the thickness, and the length that extends from the outer circumference of the plug body to the electric introduction body insertion hole side. L is set within the range of the following equation (2), and a thick wall portion of the plug body;

[0009]

[Equation 2]

In the claims and the following claims, the light-transmitting ceramics are formed of ceramics, and allow light-transmitting materials such as sapphire glass in addition to alumina ceramics. Further, excess sodium means that the amount of enclosed sodium is larger than the complete amount of evaporation of sodium that is evaporated during lamp lighting. Therefore, even if the disappearance of sodium occurs, the lost part can be replenished with the surplus part, so that it is possible to prevent or suppress the decrease of the evaporation amount during lighting,
Therefore, it is possible to prevent a decrease in luminous efficiency. The integral formation of the ceramic cylindrical body and the stopper means a state in which the cylindrical body and the stopper are directly joined by firing or the like without an adhesive such as glass solder. The same applies to the connection with the thick portion.

Further, the maximum thickness of the thick wall portion of the plug may be 1/2 or more of the protruding length L.

According to the present invention, both end portions in the axial direction of the airtight container are formed to have a large diameter, but since the thick portion is integrally formed on the outer peripheral portion of the plug body joined to the open end of the cylindrical body. The mechanical strength of both axial end portions of this airtight container can be enhanced. Therefore, it is possible to reduce or prevent the occurrence of cracks at the joint between the cylindrical body and the plug during the life of the lamp.

By setting the protruding length L of the thick wall portion of the plug body toward the electric introduction body insertion hole side within a predetermined range,
Since the sodium accumulated on the thick portion of the plug body is kept away from the sealing material for filling the electric introduction body insertion hole, sodium is reduced by contacting the sealing material and disappearing. be able to.

When the thick portions are formed on the outer peripheral surfaces of both axial ends of the airtight container as in the prior art 1, heat conduction at the tube ends is promoted to obtain the coldest part temperature. Although difficult, according to the present invention, since the thick part of the plug body is provided in the airtight container, it is easy to obtain the temperature of the coldest part.

According to another aspect of the ceramic discharge lamp of the present invention, the hermetic container is a monolithic tube in which a tubular body and a plug body that hermetically seals both open ends of the tubular body are integrally formed of translucent alumina ceramics. Is characterized in that.

According to the present invention, since the cylinder body and the plug body of the airtight container are integrally formed, the airtightness of the airtight container can be enhanced and the deterioration of the airtightness can be prevented. .

A ceramic discharge lamp according to a third aspect of the present invention is characterized in that the hermetic container is integrally formed by inserting plug bodies into both open ends of the cylindrical body and integrally sintering the same.

According to the present invention, since the plug is inserted into both axially open ends of the cylinder of the airtight container and then integrally sintered, the cylinder and the plug are separately molded. Can be mass produced.

Since the plugs are inserted into both open ends of the cylindrical body and integrally sintered, the outer diameter of the plug insertion portion swells and stress is generated. However, as described in the above claim 1. In addition, since the thick portion is integrally formed on the inner surface side of the stopper, its mechanical strength can be increased and cracks can be prevented from occurring.

According to a fourth aspect of the ceramic discharge lamp of the present invention, the cylindrical body has an axially intermediate portion between the pair of electrodes in a thickness before sintering of 0.5 to 1.5 mm. To do.

According to the present invention, since the thickness of the light-transmissive cylinder is 0.5 mm or more, it is possible to effectively prevent the mechanical strength of the cylinder from being lowered.

Further, since the wall thickness of the cylinder is 1.5 mm or less, it is possible to prevent the light transmission of the cylinder from being lowered and the lamp efficiency from being lowered.

A ceramic discharge lamp according to a fifth aspect is characterized in that a metal halide is enclosed in an airtight container.

According to this claim, the above-mentioned claims 1 to 4
Any one of the inventions can be applied to a metal halide lamp in which a halide is enclosed in an airtight container.

In the ceramic discharge lamp according to a sixth aspect of the present invention, the sealing material for sealing the electric introduction body in the insertion hole of the plug body is a glass containing aluminum oxide and calcium oxide as main components and yttrium oxide and strontium oxide added. It is characterized by being a solder.

According to the present invention, since the sealing material for sealing the electric introducing member in the introducing hole of the stopper is the glass solder,
When sodium comes into contact with this glass solder, it reacts with it and sodium disappears. However, in the present invention, as described above, the thick portion L of the outer peripheral portion of the plug body where sodium accumulates is set to a distance where the excess sodium does not approach the glass solder so that the excess sodium approaches the glass plate solder. Therefore, it is possible to prevent sodium from coming into contact with the glass solder and disappearing.

A ceramic discharge lamp according to a seventh aspect of the present invention is characterized by including a translucent outer tube that accommodates an airtight container.

According to the present invention, since the arc tube, which is an airtight container, is housed in the translucent outer tube, the arc tube can be protected and electrically insulated.

A ceramic discharge lamp according to claim 8 is provided with the ceramic discharge lamp according to any one of claims 1 to 7; and a lighting circuit for supplying electric power to the ceramic discharge lamp to stably light it. It is characterized by being

A ceramic discharge lamp according to a ninth aspect is characterized by including the ceramic discharge lamp according to any one of the first to seventh aspects; and a lighting fixture main body that houses the ceramic discharge lamp.

The ceramic discharge lamp according to claim 10 is
The lighting device according to claim 8; and a lighting fixture main body that houses the lighting device.

Therefore, the lighting device according to claim 8,
Since the luminaire of 9 and the luminaire of 10 include the ceramic discharge lamp according to any one of claims 1 to 7, they have substantially the same operation and effect.

[0033]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described with reference to FIG. 1 to 8, the same or corresponding parts are denoted by the same reference numerals.

FIG. 2 is a partial vertical cross-sectional view of the first embodiment in which the present invention is applied to a high-pressure sodium lamp. In this figure, the high-pressure sodium lamp 11 is placed in a valve 12 which is an airtight container and has an appropriate amount. Mercury and Argon (A
r), xenon (Xe), krypton (Kr), neon (Ne), etc., and excess sodium are enclosed. Excess sodium means an amount larger than the complete evaporation amount of sodium which is almost completely evaporated when the lamp is turned on.

The bulb 12 is made of translucent alumina (Al
₂ O ₃ ) Ceramics is formed into, for example, a closed cylindrical shape, and the cylindrical valve body 13 and the disk-shaped end plugs 14 and 15 at both axial ends thereof are integrally formed into a monolithic tube. I am configuring.

As an example of the method for manufacturing this monolithic tube, the cylindrical valve body 13 and the end plugs 14 and 15 are individually molded from translucent alumina ceramics, and after sintering, the valve body 13 is formed. There is a method of integrally forming the end plugs 14 and 15 by inserting the end plugs 14 and 15 into the respective open end portions and integrally sintering them.

Insertion holes 14a and 15a penetrating in the plate thickness direction are formed in the central portions of the both end plugs 14 and 15, and niobium Nb, or niobium Nb and zirconium are inserted into these insertion holes 14a and 15a. Electric introduction bodies 16a and 16b made of an alloy with Zr or the like are inserted, and the electric introduction bodies 16a and 16b are hermetically joined in the insertion holes 14a and 15a by a glass solder 17 which is a sealing material.

As the glass solder 17, there is one in which aluminum oxide and calcium oxide are the main components, and yttrium oxide and strontium oxide are added.

Electrodes 18a and 18b are welded to the respective projecting inner ends of the respective electric introducing bodies 16a and 16b which project into the bulb 12. Each of the electrodes 18a, 18b is formed by winding the electrode coils 20a, 20b made of tungsten a plurality of times around the tip ends of the electrode shafts 19a, 19b made of tungsten, respectively.
b to have applied, for example, electron emission material such as BaO-CaO-WO ₃ (emitter).

However, in this valve 12, the valve body 1
Since the end plugs 14 and 15 are press-fitted into both axially open ends of No. 3 and integrally sintered, both ends in the axial direction are slightly bulged in the outer diameter direction and are thicker than the outer diameter in the axial middle portion. Since the end portion of the valve body 13 is curved so as to bulge in the outer diameter direction, it is possible that stress is generated in the curved portion.

Therefore, cracks are likely to occur at both axial end portions of the bulb 12 as in the conventional lamp.

Therefore, in the first embodiment, as shown in FIG. 1, the meat is formed on the inner end faces of the outer peripheral portions of the end plugs 14 and 15, that is, on the portions where amalgam of excess sodium Na and mercury (Hg) is likely to accumulate. The thick portions 14b and 15b are integrally formed to enhance the mechanical strength. Each thick portion 14b, 1
5b maximizes the wall thickness h on the outer peripheral surface side of each end plug 14, 15 joined to the inner peripheral surface of the open end of the valve body 13, and gradually decreases toward the insertion holes 14a, 15a side for the electric introducer. A downward slope is formed.

However, if the inner peripheral ends of the thick portions 14b and 15b are too close to the electric introduction body insertion holes 14a and 15a, the protruding length L is too long.
The amalgam of sodium Na and mercury (Hg) accumulated on 15b is guided to the descending inclined surface, and the insertion hole 1 for electric introduction is introduced.
There is a risk of contact with the glass solder 17 filled in 4a and 15a to cause loss of sodium. Therefore, in the present embodiment, the protruding length L protruding from the outer peripheral surface of the thick portions 14b, 15b to the insertion holes 14a, 15a side is configured so as to satisfy the following mathematical expression (3), and excess sodium is added to the glass. Keep away from solder 17.

[0044]

(Equation 3) However, the maximum thickness h of the thick portions 14b and 15b may be 1/2 L or more.

FIG. 3 shows a high-pressure sodium lamp 11 having the above-described structure, which is housed in a light-transmitting outer tube 22 made of, for example, hard glass as a light-emitting tube.
FIG. 4 is a front view of an example of the heavy-tube sodium lamp 21, and FIG.

That is, the double-tube sodium lamp 21 has an outer tube 22 having an elliptic spherical bulge at the center thereof, and a small diameter top portion 22a and a neck portion 22b at both ends in the longitudinal direction. So-called B
It is T-shaped. A cap 23 is provided at the end of the neck 22b.
To hold the inside of the outer tube 22 in vacuum.

A support wire 24 is housed in the outer tube 22. The support wire 24 is a conductive wire made of stainless steel or the like formed in a rectangular frame shape. The upper portion of the support wire 24 is locked inside the top portion 22a of the outer tube 22 via the elastic piece 25, and the lower portion of the support wire 24 is Is welded to the sealing wire 26a. The sealing line 26a is sealed to the stem 27.

In FIG. 3, one electric lead-in body 16a led out from the upper end of the arc tube 11 is electrically and mechanically connected to the support wire 24 at its outer end portion via the conductive upper conductive holder 28. It is connected to the. The outer end portion of the other electric lead-in body 16b led out from the lower end of the arc tube 11 in the figure has a lower holder 29 through a conductive connector 29a shown in FIG.
Is mechanically supported by.

The electric introducer 16b of the arc tube 11 is electrically connected to another stem lead wire 26b sealed to the stem 27 through the conductive connector 29a, the starter 30, and the lower holder 29. The pair of stem lead wires 26a and 26b are electrically connected to the inner surfaces of the shell 23a of the base 23 and the eyelet 23b.

On the outer surface of the arc tube 11, a proximity conductor 30a for assisting the starting is arranged close to or spirally wound. The proximity conductor 30a is made of a refractory metal made of at least one of molybdenum, tungsten, tantalum, niobium, etc., one end of which is supported by the bimetal piece of the starter 30 and the other end of which is formed on the support wire 24. It is supported by the locking part.
In addition, 30b is a getter.

The following Table 1 shows the following three types of test lamps of the high pressure sodium lamp 21 thus constructed,
When a lighting experiment was conducted in which the lamp was lit (ON) for 30 minutes under an overload condition of about 150% of the rated value and then turned off and repeated 2,500 times, the occurrence of cracks in the arc tube 11 and The increase value of the lamp voltage VL is shown. In the table, ∘ indicates no crack generation, x indicates crack generation, and t indicates the wall thickness of the valve body 13.

(Test Lamp) (1) Rated Lamp Power of Arc Tube 11: 110 W a. Dimensions of valve body 13: inner diameter φ5.5 mm, wall thickness t
0.7 mm, total length 81 mm b. Starting gas: Xenon (Xe) 150 torr c. Distance between electrodes: 57 mm d. Electrodes 18a and 18b: made of tungsten and having a diameter of 0.75 mm, a mandrel coil having a diameter of 0.25 mm and an inner coil made of a filament coil having a diameter of 0.1 mm are wound around the wells, and a diameter of 0.
The outer coil of 45mm is wound. e. Protruding length L of thick portions 14b and 15b: 0.21 to
1.2 mm f. Inner diameter of insertion holes 14a, 15a for electric introduction body: 3.0
3 mm g. Glass solder: Glass solder containing aluminum oxide and calcium oxide as main components, and yttrium oxide and strontium oxide added thereto h. Encapsulated sodium amalgam: Sodium 15wt%
Mercury amalgam 20 mg i: Emitter: barium-calcium-tungstate to impregnate the electrode coil gap.

(2) Rated lamp power of arc tube 11: 22
0W a. Dimensions of valve body 13: inner diameter φ6.85 mm, wall thickness t
0.85mm, total length 88mm b. Starting gas: Xe200 torr c. Distance between electrodes: 63 mm d. Electrodes 18a, 18b: Wings made of tungsten and having a diameter of 1.0 mm are wound with an inner coil made of a mandrel coil having a diameter of 0.4 mm and a filament coil having a diameter of 0.1 mm, and further having a diameter of 0.3 mm on the outer side.
The outer coil of is wrapped around. e. Protruding length L of thick portions 14b and 15b: 0.3 to
1.8 mm f. Inner diameter of insertion holes 14a, 15a for electric introduction body: 3.0
3 mm g. Glass solder: Glass solder containing aluminum oxide and calcium oxide as main components, and yttrium oxide and strontium oxide added thereto h. Encapsulated sodium amalgam: Sodium 15wt%
Mercury amalgam 20mg i: Emitter: barium-calcium-tungstate with electrode coil gap

(3) Rated lamp power of arc tube 11: 36
0W a. Dimensions of valve body 13: inner diameter φ8 mm, wall thickness t0.7
mm, total length 114 mm b. Starting gas: Xe200 torr c. Distance between electrodes: 85 mm d. Electrodes 18a and 18b: made of tungsten and having a diameter of 1.2 mm, a mandrel coil having a diameter of 0.35 mm and an inner coil made of a filament coil having a diameter of 0.1 mm are wound around the wells, and a diameter of 0.3 is provided outside the well.
The outer coil of mm is wound. e. Protruding length L of thick portions 14b and 15b: 0.3 to
2.1 mm f. Inner diameter of insertion holes 14a, 15a for electric introduction body: 3.0
3 mm g. Glass solder: Glass solder containing aluminum oxide and calcium oxide as main components, and yttrium oxide and strontium oxide added thereto h. Encapsulated sodium amalgam: Sodium 15wt%
Mercury amalgam 20 mg i: Emitter: barium-calcium-tungstate to impregnate the electrode coil gap.

[0055]

[Table 1]

FIG. 5 shows the crack generation state and the lamp voltage of the arc tube 11 when the dimension (Dd) / 2 of the end plugs 14 and 15 and the protruding length L of the thick portions 14b and 15b are appropriately changed. The change in VL is shown, and the line A in the figure is the protruding length L = 3
The upper limit value of / 4 × (D−d) / 2 and the line B in the figure indicate the lower limit value of the protruding length L = 1/5 × (D−d) / 2.

That is, the following is found from FIG. In other words, cracks in the lamp 11 may or may not occur when the protruding length L is 1/6 times (D−d) / 2, and if the crack length L is 1/5 times or more, it is 1
It was found that 18 out of 8 did not occur. This is because the thermal stress at the joint between the valve body 13 and the end plugs 14 and 15 where the stress is most concentrated in the production of the monolithic tube due to the thermal shock during the life of the lamp changes according to the tube inner diameter. End plugs 14 and 15 for (D-d) / 2
It is conceivable that this will be alleviated if the protruding length L of R is increased to some extent.

Further, the lamp voltage increase value VL from the initial stage is 5 / when the protruding length L of the end plugs 14 and 15 is (D-d) / 2.
If it exceeds 6 times, it will exceed 15V,
When it is within 3/4 times of (D-d) / 2, it is stable at 6 V or less. This changes according to the pipe inner diameter (D-d)
When the protruding length L of the end plugs 14 and 15 with respect to / 2 becomes larger than a certain amount, excess amalgam accumulates at the position in contact with the sealing portion of the electric introduction bodies 16a and 16b, and the conventional technique 4
It is presumed that sodium is lost during the life as in the above.

Further, in the case where the thick portion is formed outside the pipe end as in the prior art 1 described above, heat conduction at the pipe end is promoted and it is difficult to obtain the coldest portion temperature. Then, the thick portions 14b and 15b of the end plugs are provided so as to project inward of the valve body 13, and the protruding length L of the end plugs 14 and 15 is set so that the excess amalgam does not contact the glass solder 17. This has the effect of easily obtaining the coldest part temperature.

The thick portion 14 of the end plugs 14 and 15 is
b and 15b may be formed stepwise like the thick portions 14c and 15c shown in FIG. 6, and the thick portion 14 shown in FIG.
It may be a trapezoidal shape in which the corners of the inner peripheral edges of the thick portions 14c and 15c are chamfered like d and 15d, and if the protruding length L is within the set range, the protruding shape is a curved surface. However, substantially the same operational effects as those of the first embodiment can be obtained by these.

The present invention can also be applied to a metal halide lamp in which a halide is enclosed in the bulb 12. That is, when the valve 12 is made of a monolithic tube made of ceramics, a thick portion is integrally formed on the inner surface side of the outer peripheral portion of the end plug portion of the monolithic tube, and the thick portion is connected to the insertion hole side for the electric introduction body. You may comprise so that the approaching length may fall within the said predetermined range.

FIG. 8 is an overall configuration diagram showing an example of a lighting device 31 according to another embodiment of the present invention.
1 has a housing structure in which a reflection surface 32a is formed on the inner surface of the luminaire main body 32 and a lower surface or one side surface is opened, and a front glass 33 may be provided on the lower surface opening. For example, a socket 34 is provided on a side wall of the lighting fixture body 32.
Is installed. A light fixture is constructed by screwing the base 23 of the double-tube high-pressure sodium lamp 21 shown in FIGS.

The socket 34 is attached to the luminaire main body 32 or is connected to a commercial power supply 36 via a lighting circuit 35 including a ballast installed outside the luminaire main body 32. The lighting circuit 35 and the lighting fixture are housed in a lighting device body (not shown).

[0064]

As described above, according to the invention of claim 1 of the present application, both ends in the axial direction of the airtight container are formed to have a large diameter, and a thick portion is formed on the outer peripheral portion of the plug body joined to the open end of the tubular body. Since it is formed, the mechanical strength of both axial end portions of this airtight container can be enhanced. Therefore, it is possible to reduce or prevent the occurrence of cracks at the joint between the cylindrical body and the plug during the life of the lamp.

Further, by setting the distance L of the thick portion of the plug body toward the electric introduction body insertion hole side within a predetermined range, sodium accumulated on the thick body portion of the plug body is inserted into the electric introduction body insertion hole. Since it is configured so as not to come into contact with the filling sealing material, it is possible to reduce or prevent the disappearance of sodium, which is lost when the sodium comes into contact with the sealing material.

When the thick portions are formed on the outer peripheral surfaces of both axial end portions of the airtight container as in the case of the prior art 1, the heat conduction at the pipe end portion is promoted to obtain the coldest portion temperature. Although difficult, according to the present invention, since the thick part of the plug body is provided in the airtight container, it is easy to obtain the temperature of the coldest part.

According to the second aspect of the present invention, since the cylinder body and the plug body of the airtight container are integrally formed, the airtightness of the airtight container can be enhanced and the deterioration of the airtightness can be prevented. .

According to the third aspect of the present invention, since the plug is inserted into both axially open ends of the cylinder of the airtight container and then integrally sintered, the cylinder and the plug are separately formed. Can be mass produced.

Since the plugs are inserted into both open ends of the cylindrical body and integrally sintered, the outer diameter of the plug insertion portion swells and stress is generated. However, as described in claim 1 above. In addition, since the thick portion is integrally formed on the inner surface side of the stopper, its mechanical strength can be increased and cracks can be prevented from occurring.

According to the fourth aspect of the present invention, since the thickness of the light-transmissive cylinder is 0.5 mm or more, it is possible to effectively prevent the mechanical strength of the cylinder from decreasing.

Further, since the wall thickness of the cylindrical body is formed to be 1.5 mm or less, it is possible to prevent the light transmittance of the cylindrical body from being lowered and the lamp efficiency from being lowered.

The invention of claim 5 is the same as claims 1 to 4 above.
Any one of the inventions can be applied to a metal halide lamp in which a halide is enclosed in an airtight container.

According to the sixth aspect of the invention, since the sealing material for sealing the electric introduction body in the introduction hole of the stopper is glass sol, when sodium comes into contact with the glass solder, sodium reacts with the sol to cause disappearance of sodium. However, in the present invention, as described above, the thick portion L of the outer peripheral portion of the plug body where sodium accumulates is set to a distance where the excess sodium does not approach the glass solder so that the excess sodium approaches the glass plate solder. Therefore, it is possible to prevent sodium from coming into contact with the glass solder and disappearing.

According to the seventh aspect of the present invention, since the arc tube, which is an airtight container, is housed in the translucent outer tube, the arc tube can be protected and electrically insulated.

The lighting device according to claim 8 and the lighting device according to claim 9
Since the luminaire of No. 1 and the luminaire of No. 10 are equipped with the ceramic discharge lamp according to any one of claims 1 to 7, they have substantially the same operation and effect.

[Brief description of drawings]

FIG. 1 is an enlarged view of a main part of FIG.

FIG. 2 is a longitudinal sectional view of a high pressure sodium lamp which is a first embodiment of a ceramics discharge lamp according to the present invention.

FIG. 3 is a front view of an example of a double-tube high-pressure sodium lamp in which the high-pressure sodium lamp shown in FIG. 2 is housed in an outer tube as an arc tube.

FIG. 4 is a side view of FIG. 3;

FIG. 5 is a graph showing a crack generation state and a change in lamp voltage due to the (D−d) and the protruding length of the end plug of the high-pressure sodium lamp shown in FIGS.

FIG. 6 is a longitudinal sectional view of a main part of another embodiment of the present invention.

FIG. 7 is a vertical cross-sectional view of a main part of still another embodiment of the present invention.

FIG. 8 is a configuration diagram of an embodiment of a lighting device including a lighting device and a lighting fixture according to the present invention.

FIG. 9 is an enlarged longitudinal sectional view of an end of a conventional high pressure sodium lamp.

[Explanation of reference numerals] 11 high-pressure sodium lamp (light emitting tube) 12 bulb (airtight container) 13 valve body 14,15 pair of end plugs 14a, 15a insertion hole for electric introduction body 14b, 14c, 14d, 15b, 15c, 15d meat Thick parts 16a, 16b Pair of electric introduction bodies 17 Glass solder (sealing material) 18a, 18b Pair of electrodes 21 Double-tube high-pressure sodium lamp 22 Outer tube 23 Base 24 Support wire 27 Stem 30a Proximity conductor 31 Illuminator 32 Lighting Instrument body 32a Reflective surface 34 Socket 35 Lighting circuit

Claims (10)

[Claims] 1. A translucent body comprising a translucent ceramics cylindrical body and insertion holes formed integrally at both open ends of the cylindrical body for inserting and sealing an electric introduction body. An airtight container having a ceramics plug and having both ends in the axial direction formed to have a diameter larger than that of the middle part of the cylindrical body; and excess sodium stored in the end sealed in the airtight container. A discharge medium containing; a pair of electrodes for generating a discharge in the airtight container; an outer peripheral inner end face of each plug body, integrally formed so as to project inward of the airtight container to increase the thickness of the plug, A ceramic discharge comprising: a plug thick wall portion having a length L protruding from the outer periphery of the body to the electric introduction body insertion hole side within the range of the following formula (1). lamp. [Equation 1] 2. The airtight container is a monolithic tube in which a tubular body and a plug body for hermetically sealing both open ends thereof are integrally formed of translucent alumina ceramics. The ceramic discharge lamp according to claim 1. 3. The ceramics according to claim 1, wherein the airtight container is integrally formed by inserting plug bodies into both open ends of the cylindrical body and integrally sintering the same. Discharge lamp. 4. The cylindrical body has a thickness before sintering of an axially intermediate portion between the pair of electrodes set to 0.5 to 1.5 mm. The ceramic discharge lamp according to any one of the above. 5. The ceramic discharge lamp according to claim 1, wherein a metal halide is enclosed in an airtight container. 6. The sealing material for sealing the electric introduction body in the insertion hole of the plug body is a glass solder containing aluminum oxide and calcium oxide as main components, and yttrium oxide and strontium oxide added. The ceramic discharge lamp according to any one of claims 1 to 4. 7. The ceramic discharge lamp according to claim 1, further comprising a translucent outer tube containing an airtight container. 8. A lighting device comprising: the ceramics discharge lamp according to claim 1; and a lighting circuit for supplying electric power to the ceramics discharge lamp for stable lighting. apparatus. 9. A lighting fixture comprising: the ceramic discharge lamp according to claim 1; and a lighting fixture main body that houses the ceramic discharge lamp. 10. A lighting device comprising: the lighting device according to claim 8; and a lighting fixture main body that houses the lighting device.