TWI509655B - Discharge lamp - Google Patents

Description

Discharge lamp

The present invention relates to a discharge lamp which can be used as a light source for lithography, sterilization treatment, and the like, and more particularly to an electrode structure of a high output power discharge lamp such as a short arc discharge lamp.

A high-intensity light can be irradiated by a short-arc discharge lamp or the like, and used as a light source of an exposure device or the like. In order to increase the size of an exposure target such as a liquid crystal substrate and to increase productivity, it is necessary to increase the output of the discharge lamp, which is accompanied by an increase in rated power consumption as much as possible.

If the rated power is increased, the amount of current of the lamp will increase and the temperature of the electrode will rise. In particular, the front end portion of the anode is heated to a high temperature, and melts and evaporates as time passes through the front end portion. As a result, since the unstable arc discharge and the metal adhere to the inner surface of the tube, the luminous efficiency is lowered, and the life of the lamp is reduced due to the electrode loss.

In order to prevent such electrode melting due to overheating, for example, the electrode surface is fin-shaped to dissipate heat, or the surface of the tungsten electrode is carbonized to form a heat dissipation layer to prevent evaporation of the electrode (for example, refer to Patent Document 1).

On the other hand, it is possible to prevent overheating of the electrode by sealing the metal material having a high thermal conductivity and a melting point lower than that of the electrode body metal without performing electrode surface treatment (refer to Patent Document 2). The heat of the metal material and the heat convection in the internal space of the electrode by melting cause the heat at the tip end portion of the electrode to be transported to the electrode support rod, thereby achieving uniform temperature of the entire electrode.

In addition, in order to prevent heat from the tip end portion of the electrode from escaping from the side of the electrode, a hollow ceramic sleeve may be disposed around the electrode body, and the temperature of the electrode may be suppressed by the ceramic having high thermal conductivity (refer to Patent Document 3).

[First technical literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2003-249191

Patent Document 2 Japanese Patent No. 3994880

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2008-186790

Even if the surface of the electrode is carbonized, the thermal conductivity inside the electrode is not improved, and the tip end portion of the electrode is still overheated. Further, when the ceramic material is configured as a heat transfer material, the insulation of the ceramic affects the increase in the amount of current flowing between the electrodes, and the electrode structure is restricted. On the other hand, even if a metal material having a high thermal conductivity and a low melting point is sealed in the inside of the electrode, the eigenvalue of the thermal conductivity of the metal itself is at the upper limit, and if the electric power and the current are gradually increased, the electrode tip end portion cannot be reliably suppressed. Overheating and melting. Therefore, an object of the present invention is to effectively suppress the temperature rise of the electrode in a discharge lamp of a large output.

The discharge lamp of the present invention comprises: a pair of electrodes disposed oppositely in a discharge tube; and a pair of electrode support rods supporting the electrodes; at least one of the electrodes or electrode support rods having a heat transfer body, the heat transfer body It is formed by molding a material which exhibits a thermal conductivity of carbon or carbon which is larger than the thermal conductivity of the metal. Further, the heat transfer body constitutes at least a part of the electrode or the electrode support rod in an integral structure.

Here, the heat transfer body is a structure which has a structure in which carbon is contained in its entirety and is integrated. A carbon fiber bundle can be used as a heat transfer body using a carbon fiber or a particulate carbon substrate as a material. For example, a carbon fiber bundle can be bundled into a heat transfer body by bundling carbon fibers into a tubular metal member such as tantalum. Further, powdery carbon may be molded as a carbon substrate. On the other hand, the heat transfer body may be a heat transfer body having only a carbon (graphite) crystal structure, or a metal/carbon composite material such as a C/C composite material or a metal to which tungsten or the like is added. For example, a heat transfer body may be formed by mixing a metal such as powdered tungsten. Further, the heat transfer body may be made of a carbon nanofiber such as a carbon nanotube.

Since the heat transfer body has a carbon-based structure, the thermal conductivity is superior to that of the metal, and the melting point is the same as or higher than that of the metal. Therefore, during the discharge, the heat of the tip end portion of the electrode is efficiently transported by the heat transfer body, and the temperature of the entire electrode is made uniform. Since heat can be diffused from the electrode body via the support rod, the temperature of the electrode can be lowered, the wear of the electrode can be suppressed, and the life of the lamp can be extended. Further, since the heat transfer body has electrical conductivity and has stable strength with respect to heat, external force, and the like, temperature rise can be suppressed even by using various electrode structures.

The front end of the anode or the like is most likely to heat up due to electron impact during discharge. In order to efficiently transfer the heat of the tip end portion of the electrode to the electrode support rod, it is preferable to constitute the heat conductor so as to extend in the electrode axis direction at least inside the electrode (as the electrode itself or the electrode support rod).

The electrode structure having the heat transfer body can be configured in various forms, and the heat transfer body can be provided as a part of the electrode or the entire electrode can be configured as a heat transfer body. When the heat transfer body is provided as a part of the electrode, it can be applied to various electrode structure portions such as the electrode tip end portion, the electrode inside, and the electrode side surface portion. Further, the electrode may be replaced by an electrode support rod to form a heat transfer body.

Once the carbon is released into the discharge tube, carbon adheres to the inner surface of the discharge tube, forming a carbon film on the inner surface of the tube to reduce the luminous efficiency. Therefore, it is preferable that the tip end portion of the electrode for temperature rise is made of a metal such as tungsten.

Further, in order to prevent carbon from being released from the side surface of the electrode, it is preferred to form an internal space in the electrode body in the direction of the electrode axis, and to accommodate the heat transfer body in the internal space to form an electrode having a tip end portion of the metal electrode and a heat transfer body. . For example, when the heat transfer body is formed by passing through the carbon fiber bundle in the tubular member, it is preferable to provide the heat transfer body in the internal space in a state in which the carbon fiber bundle protrudes from the tubular member in the direction of the electrode axis.

In short arc discharge lamps, etc., the lamps are arranged in the vertical direction, and the electrode support rods support the electrodes. In order to securely hold the electrode, it is preferable to provide an electrode cover which is joined to the electrode support rod and the electrode body to seal the internal space. In order to ensure the connection between the electrode cover and the electrode body and the electrode support rod, the size of the heat transfer body can be adjusted to the size of the internal space, and the internal space can be filled without a gap.

In order to perform heat transfer by convection, the heat transfer body can be accommodated in the internal space to provide a void, and the heat conductive material having a melting point lower than the melting point of the electrode body can be sealed in the internal space. During discharge, heat convection is generated in the internal space by melting of the thermally conductive material, and heat is transferred to the electrode support rod. Further, in order to efficiently transport the heat of the molten thermally conductive material, it is preferred to bond the heat transfer body to the electrode cover and to extend the heat transfer body to contact the thermally conductive material during lighting. In particular, in order to release heat transferred by the heat convection from the side surface of the electrode, the heat transfer body may constitute a cylindrical portion of the electrode body in which the internal space is formed.

Since the heat expansion rate of the heat transfer body and the electrode cover are different, it is easy to crack from the joint portion in the lighting. In order to ensure the integral combination of the heat transfer body and the electrode cover, a gradation structure can be provided at the joint portion between the heat transfer body and the electrode cover. Here, the "gradient structure" means a structure in which the composition and structure of the internal structure are continuously and stepwisely changed at the joint portion and the vicinity thereof, and the material function such as temperature change is accompanied by the gradual structure and continuity and phase. Change in place.

On the other hand, the electrode cover may be omitted, and the concave portion may be formed in the electrode body to open the internal space to the electrode support rod side. In this case, the electrode support rod may be joined to the heat transfer body.

Alternatively, in order to reliably hold the electrode, the electrode support rod is extended to the bottom surface of the internal space to hold the electrode front end portion. At this time, the cylindrical portion of the electrode body in which the internal space is formed may be formed of a heat transfer body. Further, in order to dissipate the heat of the tip end portion of the electrode to the electrode support rod, the heat transfer body may be formed into a cylindrical shape, and a space between the heat transfer body and the electrode support rod may be disposed coaxially, and the internal space may be disposed. The bottom surface is connected to the outside.

Alternatively, the electrode support bar and the electrode wire positioning device may be joined without an internal space in the electrode, and the electrode trunk portion other than the electrode tip end portion may be formed. In this case, it is preferable to provide a gradation structure in the joint portion between the heat transfer body and the tip end portion of the electrode to enhance the integrated structure.

Further, a shaft portion may be provided on the electrode, and the shaft portion extends from the electrode tip end portion in the electrode axis direction to be coupled to the electrode support rod, and a cylindrical heat transfer body is disposed coaxially around the shaft portion as the inside of the electrode. Set the construction of the internal space.

On the other hand, when the electrode support bar and the electrode are configured as a heat transfer body, heat at the tip end portion of the electrode is transmitted to the electrode support rod and is sent to the seal tube side. Usually, the temperature of the sealed tube is adjusted by cooling air, water cooling, etc., and the temperature of the electrode can be effectively adjusted by transferring the heat of the electrode to the side of the sealed tube. In order to release the heat of the tip end portion of the electrode to the outside, it is preferable to form an internal space which is open on the electrode support rod side, and the electrode support rod extends to the bottom surface of the internal space to be joined to the electrode body. For example, an electrode cover may be provided which is joined to the electrode body and formed with a hole communicating the internal space and the outside of the electrode.

According to the present invention, even in a discharge lamp of a large output power, the temperature rise of the electrode can be effectively suppressed.

[Best form for implementing the invention]

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

Fig. 1 is a schematic plan view of a short arc type discharge lamp of the first embodiment.

The short arc discharge lamp 10 has an arc tube 12 made of transparent quartz glass. In the arc tube 12, the cathode 20 and the anode 30 are arranged to face each other at a predetermined interval. On both sides of the arc tube 12, sealed tubes 13A and 13B made of quartz glass are integrally formed by being connected to the arc tube 12. Here, the arrangement of the short arc discharge lamp 10 is such that the electrode axis is in the vertical direction.

Conductive electrode support rods 17A and 17B supporting the cathode 20 and the anode 30 are disposed inside the sealed tubes 13A and 13B, and the electrode support rods 17A and 17B are respectively connected to the conductive lead rods 15A via the metal foils 16A and 16B. 15B connection. Both ends of the sealing tubes 13A and 13B are plugged by the metal covers 19A and 19B, and the sealing tubes 13A and 13B are welded to the glass tube and the glass rod (not shown) provided in the discharge tube, thereby illuminating the inside of the arc tube 12. The discharge space is sealed. In the arc tube 12, a discharge gas such as mercury or argon gas is sealed.

The lead bars 15A and 15B are power supply units (not shown) connected to the outside, and supply power to the cathode 20 and the anode 30 via the lead bars 15A and 15B. Once a voltage is applied between the cathode 20 and the anode 30, an arc discharge occurs between the electrodes, and light is emitted from the arc tube 12.

Fig. 2 is a schematic cross-sectional view of the anode 30.

The anode 30 has a bottomed cylindrical anode body (hereinafter referred to as "electrode body") 42 including an electrode tip end portion 43, and the heat transfer body 40 is housed in a cylindrical inner space 42S formed in the electrode body 42. The internal space 42S is formed in the cylindrical portion 44, and the cylindrical portion 44 extends from the electrode distal end portion 43 toward the electrode support rod side, and the heat transfer body 40 is filled in the internal space 42S without a gap. The size of the heat transfer body 40 is set to conform to the size of the internal space 42S.

The annular electrode cover 46 is coupled to the cylindrical portion 44 of the electrode body 42 to seal the heat transfer body 40. The electrode support rod 17B is connected to the electrode cover 46, and the anode 30 is held via the electrode cover 46.

The electrode body 42, the electrode cover 46, and the electrode support rod 17B are made of tungsten. On the other hand, the heat transfer body 40 extending along the electrode axis E inside the anode 30 is a tungsten/carbon composite material having a thermal conductivity higher than that of the metal constituting the electrode body (hereinafter referred to as "W/" C composite material"). The W//C composite material is a material in which tungsten is coated on a carbon substrate such as a C/C composite material, or powdered carbon is mixed with powdered tungsten. The temperature of the heat transfer body 40 at a normal temperature or a discharge temperature is higher than the thermal conductivity of tungsten constituting the electrode body 42, and the strength against heat and impact from the outside is large. Further, the heat transfer body 40 has a high melting point, and substantially does not cause melting due to heat during discharge.

As a method of forming the anode 30, the electrode body 42 having the internal space 42S formed in advance is sealed with a heat transfer body 40 having a size conforming to the internal space 42S. Then, the separately prepared electrode cover 46 is joined and integrated with the cylindrical portion 44 of the electrode body 42. As an integrated method, it may be a fusion welding, a brazing, a soldering or the like.

The heat transfer body 40 is connected to the bottom surface 42T of the internal space 42S, that is, the electrode front end portion 43. Therefore, the heat generated by the electron impact of the electrode tip end surface 43S during the discharge is transported to the electrode support rod side by the heat transfer body 40 having excellent thermal conductivity. Thereby, the electrode tip end portion 43 does not locally overheat, and the temperature of the anode 30 is uniformly uniform.

As described above, in the short arc type discharge lamp 10 in which the cathode 20 and the anode 30 are opposed to each other in the arc tube 12, the internal space 42S is formed in the electrode body including the electrode tip end portion 43. Then, a heat transfer body 40 made of a W/C (tungsten/carbon) composite material is sealed in the internal space 42S of the anode 30, and the internal space 42S is sealed by the electrode cover 46 coupled to the electrode support rod 17B and the electrode main body 42.

By providing the heat transfer body 40 inside the anode 30, the temperature of the entire anode is made uniform, and it is possible to prevent the loss of transparency due to melting and evaporation of the electrode tip end portion 43, thereby reducing the luminous efficiency and suppressing electrode loss. Further, since the heat transfer body 40 is electrically conductive, even if the electric power is increased and the amount of current is increased, the discharge is not affected.

Since the electrode cover 46, the electrode main body 42, and the electrode support rod 17B having the same thermal conductivity are integrally joined by metal, the bonding property is excellent, and the electrode supporting rod 17B can surely hold the anode 30. Further, since the heat transfer body 40 is not exposed to the surface of the electrode, there is no case where carbon is released into the arc tube 12 during discharge to form a carbon thin film in the tube to lower the luminous efficiency. Further, by forming the internal space 42S in the anode 30, the electrode is made lighter. Further, the heat transfer body 40 may be bonded to the electrode body 42 by welding or the like. Further, the size of the heat transfer body 40 may be adjusted, and the heat transfer body 40 may be sealed in the internal space 42S so as to provide a gap.

Next, the second embodiment will be described using FIG. In the second embodiment, unlike the first embodiment, a space is provided in the space inside the electrode to seal the heat conductive material which is melted during discharge. The other configuration is substantially the same as that of the first embodiment.

Fig. 3 is a cross-sectional view showing the anode of the short arc type discharge lamp of the second embodiment.

The anode 130 has an internal space 142S as in the first embodiment, and The electrode body 142 including the electrode tip end portion 143, the electrode cover 146, and the electrode support rod 17B are integrally joined. The columnar heat transfer body 140 has a diameter smaller than the diameter of the inner space 142S and extends in the direction of the electrode axis. One end 140A of the heat transfer body 140 is coupled to the electrode cover 146, and the other end 140B is not in contact with the bottom surface 142T of the internal space 142S, that is, the electrode front end portion 143.

The electrode cover 146 and the heat transfer body 140 are respectively prepared by sintering the electrode cover 146 and the heat transfer body 140, and are welded or screwed by laser welding, brazing and soldering, resistance welding, press-fitting, etc. A conventionally known method such as screw-in) can be joined.

In the internal space 142S, the heat conductive material 150 is sealed so as to provide a gap, and during the discharge, the heat conductive material 150 is melted and comes into contact with the heat transfer body 140. The heat conductive material 150 is composed of a metal material having a melting point lower than the melting point of the electrode body 142 (for example, gold, silver, copper, indium, zinc, lead, or the like, or an alloy of the above combination).

When the lamp is formed, a hole in which the rod-shaped heat transfer body 140 is fitted is formed in the block of the heat conductor 150, and is sealed in the internal space 142S. Then, when the temperature of the electrode tip end portion 143 rises due to the discharge, the heat conductor 150 is melted, and the liquid heat conductor contacts the heat transfer body 140.

During the discharge, convection occurs in the void portion of the internal space 142S by the melting of the heat conductive material 150. Thereby, the heat of the electrode tip end portion 143 of the electrode tip end surface 143S is sent to the electrode support rod 17B, and the temperature of the anode 130 is made uniform.

Further, since the heat transfer body 140 is in contact with the heat conductive material 150 during discharge, the heat of the molten heat conductive material 150 can be efficiently transferred to the electrode support rod side. Further, in order to make the bonding of the heat transfer body 140 and the electrode cover 146 stronger, the electrode cover 146 may be formed by replacing tungsten with molybdenum. Alternatively, the heat transfer body 140 may be combined with the inner surface of the cylindrical portion 144 instead of the electrode cover.

Next, a short arc type discharge lamp of the third embodiment will be described using Fig. 4 . In the third embodiment, unlike the first embodiment, the electrode cover is not provided. The other configuration is substantially the same as that of the first embodiment.

Fig. 4 is a cross-sectional view showing the anode of the short arc type discharge lamp of the third embodiment.

The anode 230 has an electrode body 242 which is composed of an electrode tip end portion 243 including an electrode tip end surface 243S and a cylindrical portion 244, and the heat transfer body 240 is buried in the internal space 242S formed in the electrode body 242 without a gap. . As shown in Fig. 4, the surface 240S of the heat transfer body 240 is exposed to the outside of the electrode, and the internal space 242S is not sealed. The heat transfer body 240 is joined to the front end portion 17S of the electrode support rod 17B by press fitting, welding, or the like.

Since the heat transfer body 240 is exposed to the outside of the electrode, heat sent to the tip end portion 243 of the electrode can be easily released to the outside, and the temperature rise of the anode 243 can be suppressed. In addition, since the electrode cover is not provided, the electrode can be made lighter.

Next, a short arc type discharge lamp of the fourth embodiment will be described using FIG. In the fourth embodiment, unlike the first to third embodiments, the entire electrode is composed of a heat transfer body.

Fig. 5 is a cross-sectional view showing the anode of the short arc type discharge lamp of the fourth embodiment.

The anode 330 is entirely constituted by the heat transfer body 340 and joined to the electrode support rod 17B. The electrode body 342 is a mixture of sintered tungsten and powdered carbon. The joining of the electrode main body 342 and the electrode support rod 17B is performed by welding, press-fitting, or the like. Since the entire anode 330 is configured by the heat transfer body, the heat transfer effect during discharge can be sufficiently exhibited, and electrode consumption can be suppressed.

Next, a short arc type discharge lamp according to a fifth embodiment will be described with reference to Fig. 6. In the fifth embodiment, unlike the fourth embodiment, the tip end portion of the electrode is made of metal. The other configuration is substantially the same as the fourth embodiment.

Fig. 6 is a cross-sectional view showing the anode of the short arc type discharge lamp of the fifth embodiment.

The anode 430 is integrally formed by the heat transfer body 440 constituting the electrode trunk portion and the electrode tip end portion 443. The heat transfer body 440 and the electrode tip end portion 443 are separately sintered and formed by conventional welding methods such as brazing, soldering, press-fitting, energy beam welding, and screwing. Alternatively, the electrode tip end portion 443 may be formed and then integrated by a cast coating in which the electrode tip end portion 443 covers the heat transfer body 440.

Since the tip end portion of the electrode whose temperature rises is composed of a metal rather than a carbon-containing heat transfer body, carbon is not released into the discharge space during discharge, and the electrode life can be prolonged.

Next, a short arc type discharge lamp of the sixth embodiment will be described using Fig. 7 . In the sixth embodiment, unlike the fifth embodiment, the joint portion between the tip end portion of the electrode and the heat transfer body has a gradation structure. The other configuration is substantially the same as that of the fifth embodiment.

Fig. 7 is an anode sectional view showing a short arc type discharge lamp of a sixth embodiment.

The anode 530 has a motor body composed of a heat transfer body 540 and an electrode tip end portion 543 made of tungsten, and a gradation structure 545 is formed between the heat transfer body 540 and the electrode tip end portion 543, and the heat transfer body 540 is a tungsten/carbon composite. material. The graded structure 545 is a layer of gradation of the tungsten/carbon composition. The uppermost layer 545S has a tungsten content of about 100%, the lowest layer 545T has a carbon content of about 100%, and the tungsten and carbon content of the uppermost layer 545S to the lowermost layer 545T is They are inversely proportional to each other. The higher the carbon content, the lower the tungsten content.

The gradation structure 545 is formed by a conventional heating and sintering method, and the mixing ratio of the powder of tungsten and carbon is sequentially changed to form a layered filling, and a tungsten/carbon compact is formed by molding of the mold, and the compacted body is formed. Slowly heat and sinter. Then, the gradation structure portion 545, the heat transfer body 540, and the electrode tip end portion 543 are integrally formed.

In this manner, by forming the gradation structure portion 545 in which the mixed layer of the tungsten particles and the carbon particles is laminated, even if the electrode front end portion 543 and the heat transfer body 540 are different in material composition, the integral portion can be surely formed integrally, and the heat is further enhanced. The strength of the external force.

Further, in the first and second embodiments, the gradation structure may be formed at the joint portion between the heat transfer body and the electrode cover. Further, in the first to sixth embodiments, the gradation structure may be formed in a joint portion with a metal such as an electrode body.

Next, a short arc type discharge lamp of the seventh embodiment will be described using Fig. 8 . In the seventh embodiment, unlike the sixth embodiment, the electrode shaft portion is provided, and the electrode tip end portion and the electrode support rod are connected by metal. The other configuration is substantially the same as that of the sixth embodiment.

Figure 8 is a cross-sectional view showing the anode of the short arc type discharge lamp of the seventh embodiment.

The anode 630 has an electrode body 642. The electrode body 642 is composed of a cylindrical electrode shaft portion 636 and an electrode tip end portion 643. The cylindrical electrode shaft portion 636 extends along the electrode axis direction around the electrode shaft portion 636. The cylindrical heat transfer body 640 is coaxially disposed to be coupled to the electrode tip end portion 643. The electrode support rod 17B is coupled to the end of the electrode shaft portion 636.

Since the electrode body 642 of the same metal is coupled to the electrode support rod 17B, the electrode support rod 17B can surely hold the anode 630.

Next, a short arc type discharge lamp of the eighth embodiment will be described with reference to Fig. 9. In the eighth embodiment, unlike the seventh embodiment, the electrode support rod is coupled to the tip end portion of the electrode. The other configuration is substantially the same as the seventh embodiment.

Figure 9 is a cross-sectional view showing the anode of the short arc type discharge lamp of the eighth embodiment.

The anode 730 is composed of a cylindrical heat transfer body 740 and an electrode tip end portion 743, and the heat transfer body 740 constitutes an anode body. The electrode support rod 17B extends in the electrode axis direction via the hole 740N of the heat transfer body 740, and is coupled to the electrode tip end portion 743. A gap is provided between the electrode support rod 17B and the heat transfer body 740, and the bottom surface 740T of the hole 740N is exposed to the outside.

The hole 740N of the heat transfer body 740 is an internal space formed as an electrode body, and the heat of the electrode tip end portion 743 is released to the outside via the heat transfer body 740 and the hole 740N. With both the heat transfer body 740 and the internal space, heat can be efficiently transported, and electrode consumption can be suppressed. In addition, since the electrode support rod 17B is directly engaged with the electrode leading end portion 743, the anode 730 is stably held.

Next, a short arc type discharge lamp of the ninth embodiment will be described using FIG. In the ninth embodiment, unlike the eighth embodiment, the electrode body surrounds the heat transfer body. The other configuration is substantially the same as the eighth embodiment.

Fig. 10 is a cross-sectional view showing the anode of the short arc type discharge lamp of the ninth embodiment.

As shown in Fig. 10, the anode 830 has an electrode body 842 having an internal space 842S formed in the same manner as the first embodiment, and a cylindrical heat transfer body 840 is inserted and disposed in the internal space 842S. The outer diameter of the heat transfer body 840 is sized to conform to the inner space 842S. The electrode support rod 17B passes through the inside of the heat transfer body 840, and its front end portion is coupled to the electrode tip end portion 843. Since the heat transfer body 840 is not exposed to the side surface of the electrode, it is possible to prevent a decrease in luminous efficiency due to the release of carbon.

Next, a short arc type discharge lamp of the tenth embodiment will be described using Fig. 11 . In the tenth embodiment, unlike the first to ninth embodiments, the electrode support rod is composed of a heat transfer body.

Figure 11 is a cross-sectional view showing the anode of the short arc type discharge lamp of the tenth embodiment.

The anode 930 is formed of a cylindrical electrode body 942 made of a metal such as tungsten, and a hole 942N is formed along the central axis. The electrode support rod 170B is composed of a heat transfer body made of a tungsten/carbon composite material. The electrode support rod 170B is inserted into the hole 942N fixed to the electrode body 942 and extends to the vicinity of the electrode front end portion of the electrode body 942. The electrode support rod 170B is bonded to the electrode body 942 by sintering or the like.

In this manner, since the electrode support rod 170B is composed of a heat transfer material having excellent thermal conductivity, the heat of the electrode tip end portion 943 is propagated to the electrode support rod 170B and is sent to the seal tube side. Since the heat is not uniformized inside the electrode but the heat is dissipated to the sealed tube which is usually cooled, overheating of the electrode tip end portion or even the entire electrode can be suppressed. Further, by effectively releasing heat from the electrode support rod, the temperature rise of the sealed tube can also be suppressed.

Next, a description will be given of a short arc type discharge lamp according to an eleventh embodiment using Fig. 12 . In the eleventh embodiment, unlike the tenth embodiment, an internal space is provided in the electrode body, and an electrode cover is provided. The other configuration is substantially the same as the tenth embodiment.

Figure 12 is a cross-sectional view showing the anode of the short arc type discharge lamp of the eleventh embodiment.

The anode 1030 is configured by bonding the electrode support rod 170B to the electrode body 1042 in which the internal space 1042S is formed, and sealing the internal space 1042S by the electrode cover 1046. A vent hole 1046N is formed in the electrode cover 1046 while forming a center hole 1046K through which the electrode support rod 170B passes. Thereby, the heat of the internal space 1042S is discharged to the outside of the electrode.

Next, a description will be given of a short arc type discharge lamp according to a twelfth embodiment using Fig. 13 . In the twelfth embodiment, unlike the second embodiment, a part of the electrode body is constituted by a heat transfer body. The other configuration is substantially the same as the second embodiment.

Figure 13 is a cross-sectional view showing the anode of the short arc type discharge lamp of the twelfth embodiment.

The anode 1130 has an electrode body 1142, and an internal space 1142S is formed in the electrode body 1142. The electrode body 1142 is composed of a metal electrode tip end portion 1143 and a bottomed cylindrical heat transfer body 1144. The electrode support rod 17B is coupled to the electrode cover 1146, and the electrode cover 1146 seals the internal space 1142S.

In the internal space 1142S, a rod-shaped heat transfer body 1140 extends along the electrode axis E and is coupled to the electrode cover 1146. Then, a heat conductive material 1150 having a melting point lower than the melting point of the metal is sealed in the inner space 1142S.

Next, a description will be given of a short arc type discharge lamp according to a thirteenth embodiment using Fig. 14. Figure 14 is a schematic cross-sectional view showing an anode 1230 of a short arc discharge lamp of a thirteenth embodiment.

The anode 1230 accommodates the heat transfer body 1240 in the cylindrical inner space 1242S formed in the bottomed cylindrical electrode body 1242. The internal space 1242S is formed in the cylindrical portion 1244, and the heat transfer body 1240 surrounded by the cylindrical narrow member 1245 is provided in the internal space 1242S, and the cylindrical portion 1244 extends from the electrode distal end portion 1243 toward the electrode support rod 17B side. The size of the heat transfer body 1240 and the narrow member 1245 is set to conform to the space of the internal space 1242S.

The annular electrode cover 1246 is coupled to the cylindrical portion 1244 of the electrode body 1242 and seals the heat transfer body 1240 and the narrow member 1245. The electrode support rod 17B is connected to the electrode cover 1246, and the electrode 1230 is held via the electrode cover 1246.

The electrode body 1242, the electrode cover 1246, and the electrode support rod 17B are made of tungsten. On the other hand, the heat transfer body 1240 extending along the electrode axis E inside the anode 1230 is a carbon fiber bundle and is housed in a narrow member 1245 made of tantalum.

The heat transfer body 1240 is manufactured as follows. First, for the cartridge, the carbon fiber bundle is passed in the coaxial direction. At this time, the length of the cylinder is shorter than the axial length of the carbon fiber bundle, and the end surface of the carbon fiber bundle protrudes from the end surface of the cylinder. Further, the end face of the carbon fiber bundle is a plane perpendicular to the axial direction.

As the method of molding the anode 1230, the electrode body 1242 in which the internal space 1242S is formed in advance is sealed with the heat transfer body 1240 conforming to the size of the internal space 1242S. Further, the internal space may be tapered to fit the heat transfer body 1240. Further, the outer peripheral surface of the cylinder can be cut with high precision, and the adhesion between the outer peripheral surface of the heat transfer body and the inner peripheral surface of the inner space 1242S can be improved. Then, the separately prepared electrode cover 1246 is joined and integrated with the cylindrical portion 44 of the electrode body 1242. As an integrated method, it may be a fusion welding, a brazing, a soldering or the like.

The heat transfer body 1240 is in contact with the bottom surface 1242T of the internal space 1242S, that is, the electrode front end portion 1243. Therefore, the heat generated by the electron impact of the electrode tip end surface 1243S during the discharge is transported to the electrode support rod side by the heat transfer body 1240 having excellent thermal conductivity. Thereby, the electrode tip end portion 1243 is not locally overheated, and the temperature of the anode 1230 is uniformized in its entirety. Preferably, the heat transfer body 1240 is pressurized and attached to the bottom surface 1242T of the internal space 1242S. Here, by cutting the cylinder to a length shorter than the axial direction of the carbon fiber bundle, the carbon fibers are expanded from the inner diameter of the cylinder, and the adhesion between the carbon fibers and the bottom surface of the inner space (the number of contacts) can be improved. Further, in order to increase the thermal conductivity between the bottom surface 1242T of the internal space and the end surface of the heat transfer body, a carbon nanotube (hereinafter referred to as CNT) may be mixed in the bottom surface 1242T of the internal space to impart a bridging effect.

As described above, according to the thirteenth embodiment, in the short arc discharge lamp 10 in which the cathode and the anode 1230 are opposed to each other in the arc tube, the internal space 1242S is formed in the electrode body including the electrode tip end portion 43. Then, in the internal space 1242S of the anode 1230, the heat transfer body 1240 composed of the carbon fiber bundle and the narrow member 1245 are sealed by the electrode cover 1246 coupled to the electrode support rod 17B and the electrode body 1242.

By providing the heat transfer body 1240 inside the anode 1230 and uniformizing the temperature of the entire anode, it is possible to prevent the electrode tip end portion 1243 from being depolarized due to melting and evaporation of the electrode tip end portion 1243, thereby reducing the luminous efficiency and suppressing electrode loss. Further, since the heat transfer body 1240 has appropriate conductivity, even if the input power is increased and the amount of current is increased, the discharge is not affected.

Since the electrode cover 1246, the electrode body 1242, and the electrode support rod 17B having the same thermal conductivity are integrally joined by metal, the bonding property is excellent, and the electrode supporting rod 17B can surely hold the anode 1230. Further, since the heat transfer body 1240 is not exposed to the surface of the electrode, there is no case where carbon is released into the arc tube during discharge to form a carbon thin film in the tube to lower the luminous efficiency. Further, by forming the internal space 1242S in the anode 1230, the electrode is made lighter. Further, the outer diameter of the narrow member 1245 may be adjusted, and the heat transfer body 1240 may be sealed in the inner space 1242S so as to provide a gap. Further, it is preferable to increase the thermal conductivity by mixing CNTs in the gap. Although ruthenium is used as the narrow member, other members having a ductile high-melting-point heat-resistant metal (for example, Nb or the like) may be used.

The method of bonding the metal to the heat transfer body can also be carried out by a method other than the above. It is also possible to provide a heat transfer body for both the electrode support rod and the electrode, or to use the same structure as the anode. Further, it is also applicable to discharge lamps of a type other than the short arc type.

The W/C composite material constituting the heat transfer body may be formed by adding tungsten to a carbon substrate other than the carbon fiber. Further, the component constituting the heat transfer body is not limited to the W/C composite material, and may be a metal/carbon (graphite) composite material or a metal/carbon nanotube (CNT) composite material to which tungsten is added. Further, the heat transfer body may be formed by using carbon fibers or particulate carbon as a raw material without adding a metal.

10. . . Short arc discharge lamp

12. . . Luminous tube

13A. . . Sealing tube

13B. . . Sealing tube

15A. . . Wire rod

16B. . . Wire rod

16A. . . Metal foil

16B. . . Metal foil

17A. . . Electrode support rod

17B. . . Electrode support rod

17S. . . Front end

19A. . . Metal cover

19B. . . Metal cover

20. . . cathode

30. . . anode

40. . . Heat transfer body

42. . . Electrode body

42S. . . Internal space

42T. . . Bottom

43. . . Electrode front end

43S. . . Front end face of electrode

44. . . Cylinder

46. . . Electrode cover

130. . . anode

140. . . Heat transfer body

140A. . . One end

140B. . . another side

142. . . Electrode body

142S. . . Internal space

142T. . . Bottom

143. . . Electrode front end

143S. . . Front end face of electrode

144. . . Cylinder

146. . . Electrode cover

150. . . Thermally conductive material (thermal conductor)

170B. . . Electrode support rod

230. . . anode

240. . . Heat transfer body

240S. . . surface

242. . . Electrode body

242S. . . Internal space

243. . . Electrode front end

243S. . . Front end face of electrode

244. . . Cylinder

330. . . anode

340. . . Heat transfer body

342. . . Electrode body

430. . . anode

440. . . Heat transfer body

443. . . Electrode front end

530. . . anode

540. . . Heat transfer body

543. . . Electrode front end

545. . . Gradient organization

545S. . . Peak

545T. . . Lowermost

630. . . anode

636. . . Electrode shaft

640. . . Heat transfer body

642‧‧‧electrode body

643‧‧‧Electrode front end

730‧‧‧Anode

740‧‧‧ heat transfer body

740N‧‧ hole

743‧‧‧Electrode front end

830‧‧‧Anode

840‧‧‧ heat transfer body

842‧‧‧electrode body

842S‧‧‧Internal space

843‧‧‧ electrode front end

930‧‧‧Anode

942‧‧‧electrode body

942N‧‧‧ hole

943‧‧‧Electrode front end

1030‧‧‧Anode

1042‧‧‧electrode body

1042S‧‧‧Internal space

1046‧‧‧electrode cover

1046K‧‧‧ center hole

1046N‧‧‧Ventinel

1130‧‧‧Anode

1140‧‧‧ heat transfer body

1142‧‧‧electrode body

1142S‧‧‧Internal space

1143‧‧‧ electrode front end

1144‧‧‧ heat transfer body

1146‧‧‧electrode cover 1146

1150‧‧‧ Thermal materials

1230‧‧‧Anode

1240‧‧‧ heat transfer body

1242‧‧‧electrode body

1242S‧‧‧Internal space

1242T‧‧‧ bottom

1243‧‧‧Electrode front end

1244‧‧‧Cylinder

1245‧‧‧Narrow components

1246‧‧‧electrode cover

E‧‧‧electrode shaft

Fig. 1 is a schematic plan view of a short arc type discharge lamp of the first embodiment.

Fig. 2 is a schematic cross-sectional view showing an anode of the first embodiment.

Fig. 3 is a cross-sectional view showing the anode of the short arc type discharge lamp of the second embodiment.

Fig. 4 is a cross-sectional view showing the anode of the short arc type discharge lamp of the third embodiment.

Fig. 5 is a cross-sectional view showing the anode of the short arc type discharge lamp of the fourth embodiment.

Fig. 6 is a cross-sectional view showing the anode of the short arc type discharge lamp of the fifth embodiment.

Fig. 7 is an anode sectional view showing a short arc type discharge lamp of a sixth embodiment.

Figure 8 is a cross-sectional view showing the anode of the short arc type discharge lamp of the seventh embodiment.

Figure 9 is a cross-sectional view showing the anode of the short arc type discharge lamp of the eighth embodiment.

Fig. 10 is a cross-sectional view showing the anode of the short arc type discharge lamp of the ninth embodiment.

Figure 11 is a cross-sectional view showing the anode of the short arc type discharge lamp of the tenth embodiment.

Figure 12 is a cross-sectional view showing the anode of the short arc type discharge lamp of the eleventh embodiment.

Figure 13 is a cross-sectional view showing the anode of the short arc type discharge lamp of the twelfth embodiment.

Figure 14 is a cross-sectional view showing the anode of the short arc type discharge lamp of the thirteenth embodiment.

17B. . . Electrode support rod

40. . . Heat transfer body

42. . . Electrode body

42S. . . Internal space

42T. . . Bottom

43. . . Electrode front end

43S. . . Front end face of electrode

44. . . Cylinder

46. . . Electrode cover

E. . . Electrode shaft

Claims (24)

A discharge lamp comprising: a pair of electrodes disposed oppositely in a discharge tube; and a pair of electrode support rods supporting the electrodes; wherein at least one of the electrodes or the electrode support rod has a heat transfer body, The heat transfer body is formed by molding a material composed of particulate or fibrous carbon having a thermal conductivity higher than a thermal conductivity of the metal; and the heat transfer body is configured as an integral structure to constitute the electrode or the electrode support rod At least a part of the heat transfer body is formed by using carbon fiber as a carbon substrate. A discharge lamp according to claim 1, wherein the heat transfer body extends in the electrode axis direction at least in the inside of the electrode. The discharge lamp according to claim 1, wherein the electrode has a metal tip end portion; and the heat transfer body constitutes a part of the electrode. The discharge lamp according to claim 3, wherein the electrode has an electrode body having an internal space formed along the electrode axis direction; and the heat transfer body is housed in the internal space. The discharge lamp according to claim 4, wherein the electrode has an electrode cover, and the electrode cover is joined to the electrode support rod and the electrode body to seal the internal space. A discharge lamp according to claim 5, characterized in that the heat transfer body is filled in the internal space without a gap. The discharge lamp of claim 5, wherein the heat transfer body is housed in the inner space and provided with a gap; and the heat conductive material having a melting point lower than a melting point of the electrode body is sealed In the interior space. A discharge lamp according to claim 7 is characterized in that the heat transfer body is joined to the electrode cover and extends in the lighting to be in contact with the thermally conductive material. A discharge lamp according to claim 8 is characterized in that the heat transfer body further constitutes a cylindrical portion of the electrode body forming the internal space. A discharge lamp according to claim 8 is characterized in that the heat transfer body has a gradation structure at a joint portion with the electrode cover. A discharge lamp according to claim 4, characterized in that the electrode support rod is joined to the heat transfer body. The discharge lamp of claim 4, wherein the electrode support rod extends to a bottom surface of the inner space to support the front end portion of the electrode. A discharge lamp according to claim 12, characterized in that the heat transfer body further constitutes a cylindrical portion of the electrode body forming the internal space. The discharge lamp according to claim 12, wherein the heat transfer body has a cylindrical shape and is disposed at a distance from the electrode support rod and disposed coaxially. A discharge lamp as described in claim 3, characterized in that The heat transfer body is joined to the electrode tip end portion and the electrode support rod to constitute a trunk portion of the electrode. The discharge lamp of claim 3, wherein the electrode has a shaft portion extending from the front end portion of the electrode along the electrode axis direction and engaging the electrode support rod; and the heat transfer body It is cylindrical and coaxially disposed around the shaft. The discharge lamp according to the first aspect of the invention is characterized in that the entire electrode including the tip end portion of the electrode is configured as the heat transfer body. A discharge lamp according to claim 1, wherein the electrode support rod is configured as the heat transfer body. The discharge lamp according to claim 1, wherein the heat transfer body is formed by bundling the carbon fibers into a carbon fiber bundle in a tubular member. The discharge lamp of claim 19, wherein the electrode has an electrode body having an inner space formed along the electrode axis direction; and the carbon fiber bundle is along the electrode from the cylindrical member The heat transfer body is provided in the internal space in a state in which the axial direction is protruded. The discharge lamp according to any one of claims 1 to 18, wherein the heat transfer body is formed by using powdery carbon as a base material. Discharge as described in any one of claims 1 to 18 A lamp characterized in that the heat transfer body is composed of a metal/carbon composite material. A discharge lamp as claimed in claim 22, characterized in that the heat transfer body is composed of a tungsten/carbon composite material. A discharge lamp according to any one of claims 1 to 18, wherein the heat transfer body comprises carbon nanofibers.