JP3773023B2 - High pressure discharge lamp and lighting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-pressure discharge lamp and a lighting device.
[0002]
[Prior art]
Conventionally, electrodes for high-pressure discharge lamps have been subjected to various cleaning, reduction treatments, and high-temperature heat treatments in the manufacturing process in order to prevent impurities present on the electrode surface and electrode material from entering the arc tube. ing.
[0003]
Further, tungsten, which is a refractory metal used for electrodes for high-pressure discharge lamps, has a large crystal grain size and decreases impurities on the metal surface when subjected to high temperature heat treatment, thereby increasing the melting point of tungsten. This has the effect of reducing the blackening of the high-pressure discharge lamp due to the scattering of the electrode material.
[0004]
However, as the crystal grain size is increased by high-temperature heat treatment, problems such as breakage of the electrode from the joint portion of the crystal that has grown greatly occur.
[0005]
In order to perform the heat treatment of the electrode while maintaining the mechanical strength of the electrode, Japanese Patent Application Laid-Open No. 11-97166 describes the crystal grain size of at least the portion of the electrode in contact with the arc tube sealing material as L / W An electrode (conventional example 1) for a high-pressure discharge lamp in which> 5 (L: length of particle diameter, W: width of particle diameter) is described.
[0006]
[Problems to be solved by the invention]
In order to perform the heat treatment while maintaining the mechanical strength as in the conventional example 1, even if the electrode is formed so as to limit the crystal grain size, impurities remain without being completely removed, thereby forming a high pressure discharge lamp. In such a case, problems such as blackening may occur during the lifetime.
[0007]
In order to reduce such problems, it is preferable to completely remove impurities, and it is effective to further increase the crystal grain size by applying heat treatment.
[0008]
However, increasing the crystal grain size may result in a decrease in mechanical strength. This is thought to be because the bond between the crystals becomes weak as the crystal grain size increases. Decreasing the mechanical strength of the high-pressure discharge lamp may cause problems such as broken electrodes during the manufacturing process and during transportation.
[0009]
An object of the present invention is to provide a high-pressure discharge lamp using an electrode that can maintain a predetermined mechanical strength even if the crystal grain size of the electrode material is increased by performing a heat treatment that can sufficiently remove impurities.
[0010]
[Means for Solving the Problems]
In the high-pressure discharge lamp of the invention of claim 1, the inside is formed into a secondary recrystallized layer, and the primary recrystallized layer covering the secondary recrystallized layer is formed on the surface with a thickness of 0.01 to 0.05 mm . And an electrode formed of a refractory metal having at least a root portion, and a translucent container enclosing at least one pair of electrodes.
[0011]
In the present invention and each of the following inventions, the definitions and technical meanings of terms are as follows unless otherwise specified.
[0012]
As the high-pressure discharge lamp, for example, general high-pressure discharge lamps such as a high-pressure mercury lamp and a metal halide lamp can be applied.
[0013]
As the refractory metal forming the electrode, metals such as tungsten, molybdenum and rhenium are allowed. When using tungsten, aluminum, silicon, doped tungsten was added doping agent, such as potassium or, also including triethyl over te de tungsten mixture of an electron emitting material such as thorium oxide allowed.
[0014]
The electrodes are subjected to high temperature heat treatment to remove internal impurities in order to suppress lamp blackening and the like. The crystal of the electrode material is grown by this high temperature heat treatment. In order to form the electrode according to the present invention, first, heat treatment is performed at a temperature at which primary recrystallization is formed on the skin of the electrode. Thereafter, the electrode is further subjected to high temperature heat treatment to form a secondary recrystallized layer inside the electrode. At this time, the electrode skin formed by the first heat treatment is formed as a primary recrystallized layer without secondary recrystallization.
[0015]
Further, the base portion of the electrode indicates a portion in contact with the translucent container that seals the electrode. For example, in an electrode composed of an electrode shaft portion and a coil portion, at least one part of the electrode shaft portion is shown.
[0016]
Transparent envelope is quartz glass, translucent, such as translucent ceramics, it has been formed by material having fire resistance and gas-tightness, surrounds the discharge space to FuSo the electrodes airtight.
[0017]
The pair of electrodes are sealed and opposed to the inside of the translucent container. When the translucent container is elongated, it is sealed at both ends. In addition, when the translucent container is spherical or oval, it is not only a double-sealing structure in which a pair of electrodes are sealed at both ends of the translucent container, but if necessary, substantially parallel from one end side. It can be set as the one-side sealing structure separated and sealed.
[0018]
In the case of a high-pressure sodium lamp, since a light-transmitting ceramic is used as the light-transmitting container, the electrode can be supported on the inner end of a tube of a sealing metal such as niobium penetrating the light-transmitting container.
[0019]
Furthermore, in the case of a metal halide lamp, quartz glass or translucent ceramic is used as a translucent container, but in the case of quartz glass, the electrode can be sealed by pinching seal or heat softening and shrinking. The base end of the electrode can be welded to a molybdenum foil embedded in the sealing portion, and the periphery of the intermediate portion can be supported by quartz glass.
[0020]
Further, the high-pressure discharge lamp configured as described above can be housed inside the outer tube.
[0021]
According to invention of Claim 1, since an electrode can fully be heat-processed at high temperature, the impurity inside an electrode member can be removed. For this reason, it is reduced that the melting point of the electrode member due to the impurities of the electrode member is lowered, and problems such as blackening due to scattering of the electrode member can be reduced.
[0022]
In addition, since the primary recrystallized layer having a thickness of 0.01 to 0.05 mm exists in the skin of the electrode, the mechanical strength of the electrode can be maintained even if the electrode is sufficiently heat-treated. Therefore, it is possible to provide a high-pressure discharge lamp that can reduce problems such as electrode breakage during the manufacturing process or transportation.
[0023]
An illumination device according to a second aspect of the present invention includes: a main body of the illumination device; the high-pressure discharge lamp according to the first aspect; and lighting means for stably lighting the high-pressure discharge lamp.
[0024]
Illumination device means a broad concept that includes any device configured to use the light emission of a high pressure discharge lamp for some purpose. Therefore, it is widely applicable to various uses such as illumination, light projection and photochemical reaction.
[0025]
For lighting, it is applicable to various lighting fixtures for indoor and outdoor use.
[0026]
As for light projection, it is adapted for light projection on a display body such as a projector, advertisement / advertisement, or a sign.
[0027]
For photochemical reaction, it is suitable for processing such as photo-curing resin and synthesis of synthetic resin.
[0028]
According to invention of Claim 2, the illuminating device which has an effect | action of Claim 1 can be provided.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of a light source device of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of an example of an embodiment of an electrode of a metal halide lamp of the present invention. FIG. 2 is an enlarged sectional view of the electrode. In addition, the same code | symbol is attached | subjected to the same part as FIG.
[0030]
The electrode 10 is formed of an electrode shaft 1 and an electrode coil 2. The electrode shaft 1 was made of trietated tungsten mixed with 1.7% thorium oxide. The electrode coil 2 uses doped tungsten having a diameter of 0.4 mm. The electrode shaft 1 has a rod shape with a diameter of 0.6 mm and a length of 11 mm.
[0031]
The electrode shaft 1 is covered with a secondary recrystallized layer 1b on a primary recrystallized layer 1a. The primary recrystallized layer 1a has a thickness of 0.01 mm to 0.05 mm, and the primary recrystallized layer 1a The length of the crystal grain size is from 0.01 mm to 0.05 mm, and is formed of 1 to 5 layers of crystal grains.
[0032]
The secondary recrystallized layer 1b is composed of crystal grains having a size of 100 times or more the crystal grain size of the primary recrystallized layer 1a. In the case of the maximum size, the width of the crystal grains is The diameter of the electrode 1 grows to a width excluding the width of the primary recrystallized layer 1a.
[0033]
An embodiment of a method for manufacturing such an electrode will be described. Since a high melting point metal such as tungsten used for the electrode 1 is difficult to manufacture by a normal melting method, it is mainly manufactured by a powder metallurgy method. The powder metallurgy method, after solidified metal powders in large pressure, thereby obtaining a solid metal by baking. A metal solid obtained by a powder metallurgy process using tungsten powder mixed with thorium oxide is drawn to process it as an electrode bar having a predetermined thickness. In the drawing process, the carbon mold is used for drawing while heating at a temperature of 1800 ° C.
[0034]
The cross section of the electrode after the drawing process is shown in FIG. A primary recrystallized layer 1a has already been formed on the skin of the electrode by heating at 1800 ° C. in the drawing process. The inside 1c of the electrode has not been recrystallized yet, and a fibrous crystal is formed.
[0035]
Then, it cuts to the length of the electrode shaft 1 and winds the electrode coil 2, and it is set as the structure of the electrode 10 in FIG.
[0036]
Further processing is performed in the state of the electrode 10. First, reduction treatment is performed by heating at 1800 ° C. for 15 minutes in a hydrogen atmosphere. Thereafter, heat treatment is performed at a high temperature of 2500 ° C. for 10 minutes in a vacuum atmosphere. The high temperature heat treatment removes impurities inside the electrode 10 and forms the secondary recrystallized layer 1a of the electrode.
[0037]
A cross-sectional view of the electrode after this treatment is shown in FIG. A secondary recrystallized layer 1b is formed inside the electrode shaft. The primary recrystallized layer 1a maintained the primary recrystallized state without progressing crystallization under the above conditions even when reheated. The crystal grain size of the secondary recrystallized layer 1b was the maximum, resulting in growing crystals to a width of 0.3 mm.
[0038]
The mechanical strength of the electrode 10 of this embodiment was compared. The electrode used for the comparison was the same material size as that of the electrode of this embodiment, but the heat for forming secondary recrystallization was further increased to 15 ° C. for 15 minutes, and the primary resurfacing of the electrode skin was performed. An electrode in which secondary recrystallization was grown to the crystal layer was used.
[0039]
In the case of the electrode of the comparative example, the bending strength of the electrode was 5 MPa or less, whereas when the electrode 10 of the present embodiment was used, the strength was 1.5 times that of 1.5 MPa.
[0040]
This is because the mechanical strength is maintained by the bonds between the crystals of the primary recrystallized layer 1a having a fine crystal grain size formed on the skin of the electrode shaft 1, and the secondary crystal layer 1b inside the electrode shaft 1 is formed. This is probably because it can be protected mechanically.
[0041]
Next, as a second embodiment, a metal halide lamp using the electrode 10 thus manufactured will be described with reference to FIG.
[0042]
In the figure, IB is an arc tube, OB is an outer tube, and B is a base. The metal halide lamp shown in the drawing is lit vertically so that the base B is positioned at the top in the lit state.
[0043]
The arc tube IB includes a translucent discharge vessel 3, a pair of upper and lower electrodes 10, and an ionization medium that does not appear in the drawing.
[0044]
The translucent discharge vessel 3 is made of quartz glass and has pinch seal portions 31 at both ends. A heat insulating film 12 is applied to the outer surface of the translucent discharge vessel 3 on the lower side during lighting.
[0045]
The electrode 10 is welded to a molybdenum foil 32 whose base end is hermetically embedded in the pinch seal portion 31. Further, the auxiliary electrode 11 is embedded in the pinch seal portion 31 in the same manner as the electrode 10 on the side located in the upper part during lighting.
[0046]
The ionization medium consists of a luminescent metal halide, a noble gas and mercury.
[0047]
The outer tube OB is made of hard glass, accommodates the arc tube IB, and encloses about 53 kPa of nitrogen at room temperature. The base B is an E39 type screw base, and is attached to the end of the outer tube OB. The base B plays a role of supplying electricity to the electrode 10 through the pair of internal introduction conductors 4a and 4b.
[0048]
In addition, an upper support frame 5 and a lower support frame 6 are disposed inside the outer tube OB in order to place the arc tube IB at a predetermined position in the outer tube OB.
[0049]
The upper support frame 5 supports the upper portion of the arc tube IB and electrically connects the electrode 10, and includes a U-shaped conductor 51, a support band 52, and a connection conductor 53. The base of the U-shaped conductor 51 is welded to the inner introduction conductor 4a. The support band 52 encloses the pinch seal portion 31 on the upper side of the arc tube IB and is welded to the side of the U-shaped conductor 51. The connection conductor 53 is electrically connected to the upper support frame 5 and the lower support frame 6. The auxiliary electrode 11 of the arc tube IB is welded to the molybdenum foil 32 in the pinch seal portion 31, and is electrically connected to the U-shaped conductor 5a via the current limiting resistor 13.
[0050]
The lower support frame 6 supports the lower portion of the arc tube IB and electrically connects the electrode 10, and includes a U-shaped conductor 61, a support band 62, a connection conductor 63, and a spring piece 63.
[0051]
The U-shaped conductor 61 and the support band 62 have the same structure as that of the lower support frame 5, but have a vertically inverted relationship. The spring piece 64 is welded to the U-shaped conductor 61 and the tip is held at a predetermined position in the outer tube OB.
[0052]
The metal halide lamp of this embodiment was turned on and the occurrence of blackening was observed. In the metal halide lamp of the present embodiment, a good light flux maintenance factor is maintained without causing blackening even after 9000 hours when blackening occurs in a metal halide lamp using a conventional electrode.
[0053]
This is presumably because the impurities inside the electrode 10 were removed by the high-temperature heat treatment of the electrode 10 and the scattering of the electrode 10 member was suppressed. Moreover, since the mechanical strength of the electrode 10 is sufficiently ensured, electrode breakage in the manufacturing process and transportation can be reduced.
[0054]
A third embodiment of the present invention will be described. In the present embodiment, the electrode of the first embodiment is made of doped tungsten as the material of the electrode shaft, and the other shapes are the same as those described in the first embodiment.
[0055]
The manufacturing method of the electrode 10 in a present Example is demonstrated. The drawing process and after the drawing process are performed in the same process until the electrode shaft 1 is cut, the electrode coil 2 is wound, and reduction treatment is performed in a hydrogen atmosphere.
[0056]
Thereafter, the electrode 10 is subjected to high temperature heat treatment. The temperature condition of the heat treatment is different from that of the first embodiment. In the present embodiment, the high temperature heat treatment is performed at 2000 ° C. for 10 minutes in a vacuum atmosphere, whereby the primary recrystallized layer 1a can be formed on the skin of the secondary recrystallized layer 1b as in the first embodiment. .
[0057]
The electrode 10 thus formed also has a mechanical strength of 15 kPa, and the mechanical strength is improved by a factor of 1.5 compared to an electrode in which the skin of the primary recrystallized layer is not formed. Further, even when the electrode 10 of the present embodiment was incorporated into a metal halide lamp, a good luminous flux maintenance factor was ensured without blackening during the lifetime.
[0058]
A third embodiment of the present invention will be described with reference to FIG. FIG. 3 shows an illumination device 7 equipped with the metal halide lamp of the second embodiment. In addition, the same code | symbol is attached | subjected to the same part as FIG.
[0059]
The lighting device 7 includes a reflective shade 71, a socket 72, a ballast 73, and the like. The base 4 of the metal halide lamp is used by being mounted on the socket 72 of the lighting device. The secondary output terminal of the ballast 73 is connected to the socket 72 to supply power to the metal halide lamp. The lighting device 7 is supported by the ceiling surface 70.
[0060]
【The invention's effect】
According to the first aspect of the present invention, since the impurities inside the electrode member can be removed by sufficiently heat-treating the electrode , the decrease in the melting point of the electrode member due to the impurity in the electrode member is reduced. It is possible to reduce problems such as blackening due to the scattering of water.
[0061]
In addition, since the primary recrystallized layer having a thickness of 0.01 to 0.05 mm exists in the skin of the electrode, the mechanical strength of the electrode can be maintained even if the electrode is sufficiently heat-treated. Therefore, it is possible to provide a high-pressure discharge lamp that can reduce problems such as electrode breakage during the manufacturing process or transportation.
[0062]
According to invention of Claim 2, the illuminating device which has an effect | action of Claim 1 can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of first and third embodiments of electrodes of a metal halide lamp of the present invention.
FIG. 2 is an enlarged cross-sectional view of the same electrode.
FIG. 3 is a front view of a metal halide lamp according to a second embodiment of the present invention.
FIG. 4 is a cross-sectional view of a lighting device according to a fourth embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Electrode shaft 1a ... Primary recrystallization layer 1b ... Secondary recrystallization layer 2 ... Electrode coil 10 ... Electrode IB ... Arc tube OB ... Outer tube

Claims (2)

A refractory metal having a secondary recrystallized layer inside and at least a root part of which a primary recrystallized layer covering the secondary recrystallized layer is formed with a thickness of 0.01 to 0.05 mm. An electrode formed by:
A translucent container in which this electrode is sealed;
A high-pressure discharge lamp comprising: A lighting device body;
A high-pressure discharge lamp according to claim 1;
Lighting means for stably lighting the high-pressure discharge lamp;
An illumination device characterized by comprising:

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