KR20200024712A - Discharge lamp and method for producing electrode for discharge lamp - Google Patents

Abstract

In a discharge lamp, heat radiation is effectively performed to suppress the temperature of an electrode (30). In the electrode (30), a cylindrical concave unit (40) is formed on a front end member (34) toward the opposite side to a front end and a columnar unit (50) is formed coaxially on a rear end member (32). The cylindrical concave unit (40) accommodates the columnar unit (50) while a gap (60) is formed therebetween along an axial direction (X) and an axial vertical direction. A surface area of the gap (60) is larger than a surface area of an electrode side portion (T) along an axial length (L1) of the gap (60).

Description

The manufacturing method of a discharge lamp and the electrode for discharge lamps {DISCHARGE LAMP AND METHOD FOR PRODUCING ELECTRODE FOR DISCHARGE LAMP}

The present invention relates to a discharge lamp with an electrode, and more particularly to an internal structure of the electrode.

In the discharge lamp, the electrode tip becomes high temperature during lighting, the electrode material such as tungsten is melted and evaporated, the discharge tube is blackened, and the lamp illuminance is lowered. In order to prevent overheating of the electrode tip portion, an electrode tip portion made of a durable metal and a body portion made of a metal having higher thermal conductivity are molded separately and joined by solid phase bonding or the like. For example, an electrode can be comprised by solid state bonding, such as SPS (refer patent document 1). By joining a plurality of members to form an electrode, the electrode can be made durable even when the electrode is enlarged, and an electrode excellent in thermal conductivity can be formed.

Japanese Patent No. 5472915

In order to increase the size of the exposure target and improve the throughput, high output (high power) of the lamp is required. As a result, the electrode temperature during lamp lighting also increases, and it is difficult to effectively suppress overheating of the electrode by merely solidifying the tip side member and the fuselage side member.

Therefore, the electrode structure which can suppress the temperature rise of an electrode effectively during lighting of a discharge lamp is calculated | required.

The discharge lamp of this invention is equipped with a discharge tube and a pair of electrode opposingly arranged in a discharge tube, At least one electrode has an internal space, the surface area of an internal space is the axis of an internal space, It is larger than the surface area of the electrode side part along the direction length. For example, the surface area of the internal space can be made larger than the surface area of the electrode side portion along the electrode axial direction.

The electrode has a recess along the electrode axial direction and a columnar portion located in the recess, and an internal space can be formed between the recess and the columnar portion. Here, "column part" and "recess part" are a part prescribed | regulated including a contact surface or a joining surface, when the electrode formed by the joining of several members is seen from the cross section, and the cross section and recess part of a columnar part are prescribed | regulated. No contact with the bottom or non-contact. For example, it has a 1st solid member which provided the recessed part, and the 2nd solid member which joined with the 1st solid member or the intermediate member joined with a 1st solid member, and formed the columnar part, and an internal space has a 1st solid It is formed between the member and the second solid member or the intermediate member.

The internal space may include a space formed by the rotation of the electrode shaft. In addition, the internal space can be formed in a user pipe shape. The heat dissipation part can be provided in the surface part of an internal space.

The discharge lamp which is another aspect of this invention is equipped with a discharge tube and a pair of electrode opposingly arranged in a discharge tube, The at least one electrode is a recess along an electrode axial direction, the columnar part located in a recess, a recess, and a columnar With the internal space formed between the parts, the volume of the columnar part is larger than the volume of the internal space.

The manufacturing method of the electrode for discharge lamps which is another aspect of this invention center-rotates a cylindrical recessed part with respect to the columnar front-end solid member which has an electrode front end surface. To the columnar rear end solid member, the tip of which is smaller in size than the cylindrical recess in a central axis rotation, and the columnar portion being coaxially arranged in the tubular recess. In the manufacturing method characterized by combining a solid member and a rear end side solid member, and forming an electrode including a front end side solid member and a rear end side solid member by solid phase joining, The cylindrical recess part and columnar part The cylindrical recesses and columnar portions are formed such that the surface area of the inner space formed between and becomes larger than the surface area of the electrode side portion along the axial length of the inner space.

According to the present invention, it is possible to effectively radiate heat in the discharge lamp to suppress the electrode temperature.

1 is a plan view of a discharge lamp as a first embodiment.
2 is a schematic cross-sectional view of an electrode of the first embodiment.
3 is a schematic cross-sectional view of an electrode as a second embodiment.
(FIG. 4) It is the graph which showed the temperature change from the bonding surface of an Example and a comparative example.

The short arc discharge lamp 10 is a large discharge lamp capable of outputting high luminance light, and has a substantially spherical discharge tube (light emitting tube) 12 made of transparent quartz glass, and has a discharge tube ( In 12), a pair of tungsten electrodes 20, 30 are disposed opposite (coaxial). On both sides of the discharge tube 12, sealing tubes 13A and 13B made of quartz glass extend from the discharge tube 12 and are integrally formed. In the discharge space DS in the discharge tube 12, mercury and rare gases such as halogen and argon gas are sealed.

The electrode 20, which is a cathode, is supported by an electrode support rod 17A. The sealing tube 13A includes a glass tube (not shown) through which the electrode supporting rod 17A is inserted, a lead rod 15A for connecting to an external power source, an electrode supporting rod 17A, and a lead rod ( The metal foil 16A etc. connecting 15A) are sealed. Similarly, mount parts, such as a glass tube (not shown), the metal foil 16B, the lead rod 15B, through which the electrode support rod 17B is inserted, are sealed also about the electrode 30 which is a positive electrode. Moreover, clasps 19A and 19B are attached to the edge part of sealing pipe 13A, 13B, respectively.

When voltage is applied to the pair of electrodes 20 and 30, arc discharge occurs between the electrodes 20 and 30, and light is emitted toward the outside of the discharge tube 12. Here, electric power of 1 kW or more is input. Light emitted from the discharge tube 12 is guided in a predetermined direction by a reflector (not shown). For example, when the discharge lamp 10 is inserted into the exposure apparatus, the radiation light becomes pattern light and is irradiated to a substrate or the like.

2 is a schematic cross-sectional view of the electrode (anode) 30. In addition, the electrode (cathode) 20 can also have the same structure.

The electrode 30 is comprised from the rear end member 32 (2nd solid member) connected with the electrode support stick 17B, and the front end side member 34 (1st solid member) which has the electrode front end surface 34D. The electrode 30 is configured by joining the rear end member 32 and the front end side member 34. Here, the rear end side member 32 and the front end side member 34 are joined by solid phase bonding such as SPS.

The rear end side member 32 is a columnar member having a center axis around the electrode axis X (hereinafter also referred to as the axial direction X) and has a columnar portion projecting toward the electrode tip surface 34D. ) 部 50 (here, columnar shape) is formed. In the front end side member 34, the cylindrical recessed part 40 surrounding the columnar part 50 is formed coaxially along the axial direction X. As shown in FIG. The cylindrical recess portion 40 faces in the opposite direction to the electrode tip surface 34D, that is, is recessed in the reverse direction. The rear end side member 32 is solid-state-joined with the edge part 34E of the front end side member 34 at the edge part 32E. In addition, you may provide a recessed part in a columnar part and a rear end member in a front end side member.

A gap (internal space) 60 between the columnar portion 50 and the cylindrical recess portion 40 extending from the solid-state bonding surface to the electrode tip side along the axial direction X and the axial vertical direction perpendicular thereto. ) Is formed over the entire circumference of the columnar portion 50. Here, the gap portion along the axial vertical direction is 60D and the gap portion along the axial direction X is 60V. The gap portions 60D and 60V are spatially connected.

As for the columnar part 50 and the cylindrical recessed part 40, the center axis | shaft coincides with the electrode axis | shaft X, and both have a symmetrical shape with respect to the electrode axis | shaft X. As shown in FIG. The bottom face 40B of the cylindrical recess 40 is also symmetrical with respect to the electrode axis X, and the gap 60 is also symmetrical with respect to the electrode axis X.

The radial distance D4 of the gap portion 60V, that is, the radial distance between the side surface 50S of the columnar portion 50 and the side surface 40S of the cylindrical recess portion 40 is the diameter of the columnar portion 50. It is short compared with (D3) (D4 <D3). The axial width L4 of the gap portion 60D is the same width as the radial width D4 of the gap portion 60V here, and is shorter than the height L3 of the columnar portion 50 (L4 <L3). The clearance gap 60 is formed in the electrode 30, and becomes the space area of a user cylinder shape.

Here, the radial width D4 and the axial width L4 are sufficiently shorter than the diameter D3 and the height L3 of the columnar portion 50, respectively, and the side surfaces 50S of the columnar portion 50, The end surface 50E is close to the side surface 40S and bottom surface 40B of the cylindrical recessed part 40, respectively, and the volume of the space which the clearance gap 60 forms is smaller than the volume of the columnar part 50. As shown in FIG. In addition, in the gap 60, a member such as a heat transfer body is not provided.

During lamp lighting, the temperature of the front end side member 34 of the electrode rises, and heat of the electrode front end side member 34 is transmitted to the columnar portion 50. The column of the columnar part 50 is transmitted to the electrode support rod 17B side, and is radiated with respect to the clearance gap 60. The heat moved not only in the axial direction X but also in the axial vertical direction is transferred from the electrode outer surface 30M to the discharge space DS.

In this embodiment, in order to effectively suppress the temperature rise of the electrode 30, the clearance gap | interval so that the surface area of the clearance gap 60 may become larger than the surface area of the electrode side part T along the axial length of the clearance gap 60. 60) is formed.

As described above, the volume of the columnar portion 50 is larger than the volume of the gap 60. As a result, the columnar portion 50 has a large amount of heat absorption, absorbs heat from the cylindrical recess portion 40, and can be effectively transported to the electrode support rod side.

On the other hand, since the radial width D4 and the axial width L4 of the gap 60 are relatively small, heat of the columnar portion 50 is transmitted to the electrode outer surface 30M to radiate heat into the discharge space DS. . In this manner, the heat radiation effect on the electrode side portion T along the axial length L1 of the gap 60 can be enhanced.

This heat dissipation effect is realized by forming the gap 60 in accordance with the rotation of the shaft at a position as far from the center of the shaft as possible. The surface area of the gap 60 in that case becomes larger than the surface area of the electrode side part T corresponding to the axial length L1.

In addition, the surface area of the clearance gap 60 in this embodiment is larger than the surface area of the whole electrode side surface T1 along the electrode axis X. As shown in FIG. That is, the electrode side surface except for the electrode tip side tapered portion 34T, the electrode support rod side tapered portion 32T, the electrode tip surface 34D, and the electrode rear end surface 32L having a small area (small surface area) radiating heat from the electrode surface. The surface area of the gap 60 is larger than the surface area.

By forming the gap 60 having a relatively large surface area in relation to the electrode side portion, it is possible to effectively suppress the rise of the electrode temperature.

By the way, in the case of the electrode structure in which the clearance gap 60 was formed between the columnar part 50 and the cylindrical recessed part 40, it is the volume of the columnar part 50 that the surface area of the clearance gap 60 mentioned above is relatively large. It can also be said that it shows larger than the volume of this clearance gap 60. Since the volume of the columnar portion 50 is larger than the volume of the gap 60, it is possible to effectively suppress the increase in the electrode temperature.

The electrode which realizes such electrode temperature suppression can be manufactured as follows. That is, the cylindrical recessed part is formed by the central axis rotation with respect to the columnar front-end solid member which has an electrode front end surface, and the columnar columnar part smaller in size than a cylindrical recessed part is formed with respect to the columnar rear-end solid member. Form with central axis rotation. At this time, the cylindrical recessed part and columnar part are formed so that the surface area of the internal space formed between the cylindrical recessed part and columnar part may become larger than the surface area of the electrode side part along the axial length of the internal space. The front-side solid member and the rear-end solid member are combined so that the columnar portion is coaxially arranged in the cylindrical recess, and an electrode including the front-side solid member and the rear-end solid member is formed by solid phase bonding such as SPS.

The space shape of the clearance 60 is not limited to a user tubular shape, For example, you may form the bottomless tubular space which does not form the axial vertical direction clearance 60D. Moreover, you may form internal spaces other than a tubular space, and the space which connects with the exterior can be formed through a sealed state or a hole. In this case, by forming a space in accordance with the rotation of the electrode shaft, the surface area can be made larger than the surface area of the electrode side portion along the length of the space axis direction. In addition, the surface area of a clearance gap (inner space) is made into the surface area of the space formed in the electrode center side rather than the electrode outer surface. In addition, you may form the sealed space which provided the heat-transfer body melted at high temperature. In this case, the surface area of the space (gap) represents the surface area of the exposed portion, and the surface covered with the heat transfer body is not included.

The heat dissipation part may be provided in the columnar part 50. For example, it is possible to comprise the structure which increases existing surface area, the structure which raises emissivity (absorption rate), heat dissipation material (heat dissipation layer of a carbon film or an oxide film), carbon nanotube, etc. Moreover, you may provide a heat radiating part in places other than the columnar part 50 (cylindrical recessed part 40, an electrode side surface, etc.).

Next, 2nd Embodiment is described using FIG. In the second embodiment, a through hole is formed in the electrode side surface.

3 is a schematic cross-sectional view of the electrode (anode) 130 in the second embodiment. As shown in FIG. 3, a plurality of through holes J1 to J4 are formed. Through-holes J1-J4 are in the range of the axial length L3 of the columnar part 50 here. By forming such through holes J1 to J4, the heat of the gap 60 can be escaped and the temperature rise of the electrode can be suppressed. Therefore, the surface area of the gap 60 including the surface areas of the through holes J1 to J4 is determined to be larger than the electrode side portion T or T1. In addition, the angle of the through hole is not limited to the electrode axis vertical direction (horizontal direction), and may be defined at a predetermined angle. In addition, the number, hole diameter, and position are appropriately determined according to the lamp size, the electrode size, and the like. For example, a through hole may be formed in the electrode end surface 34D. Moreover, you may provide a heat radiating part in 2nd Embodiment.

This invention is not limited to the above-mentioned embodiment, Various modifications are possible based on the technical idea of this invention. The electrodes shown in the first and second embodiments can also be applied to discharge lamps other than the short arc type discharge lamp. Since the temperature rise of an electrode can be suppressed, it is suitable for the discharge lamp of comparatively large electric power of 1 kW or more. The shape of this electrode can be made into a desired shape and size, such as a shape without an electrode support rod side taper part, for example. Moreover, although solid state bonding (SPS, HP etc.) is preferable for a joining method, other joining methods (for example, melt joining) can also be applied. At the time of joining, an intermediate member may be provided between the front end side member and the rear end side member so as to be in close contact between the joining surfaces. Examples of the intermediate member include rhenium, tantalum, molybdenum, tungsten or alloys thereof.

The shape, size, etc. of the columnar portion and the recessed portion are arbitrary, and may be, for example, a columnar portion whose diameter changes along the axial direction X, or a cylindrical recess portion having an axial diameter surface on the bottom surface thereof. In addition, an internal space having a large surface area can be arbitrarily formed. Moreover, it is possible to comprise a columnar part and a cylindrical recessed part with a different member, respectively. For example, it is possible to form the columnar portion (rear end member) with a member that is excellent in heat radiation and lightweight, and form the tip side member with a member having excellent heat resistance and thermal conductivity. Moreover, you may join and comprise a columnar part to a rear end side member. Specifically, tungsten, molybdenum, ceramics, or the like may be used, and an emitter may be contained, and these alloys may be applied and may be appropriately selected.

(Example)

Hereinafter, the Example which concerns on 2nd Embodiment is demonstrated.

The discharge lamp of the embodiment is a discharge lamp having an electrode provided with eight through holes in the side of the electrode and with through holes in the electrode front end surface, the total length of which is 60 mm, L1 = 28 mm, L3 = 25 mm, L4 = 3 mm, D1 = 38 mm, D2 = 26 mm, D3 = 22 mm, D4 = 2 mm, through hole diameter = 3 mm, electrode tip hole diameter = 3 mm. The surface area of the gap is larger than the surface area of the electrode side portion along the axial length of the gap (5552.3> 3286.1).

Predetermined electric power was put into such a discharge lamp, it lighted up, and temperature measurement was performed about the electrode of the stable lighting state. The temperature was measured with a thermotracer set to emissivity:? 0.68 and measurement wavelength range: 2.2 to 2.6 µm. On the other hand, as the discharge lamp of the comparative example, except for the structure which does not provide a clearance gap and a through hole, the discharge lamp which inserted the electrode like Example was similarly measured.

4 is a graph showing a temperature change on the electrode tip side of Examples and Comparative Examples. This is measured in multiple places in the electrode front end side, ie, the area | region corresponded to electrode side part T, from an abutment surface, and approximates linearization of a plot. The same applies to the comparative example. As shown in FIG. 4, it was confirmed that the electrode of the example had a lower temperature than the comparative example, and the temperature suppression was maintained even toward the electrode tip.

10: discharge lamp
30: electrode (anode)
32: trailing side member
34: tip side member
40: barrel shape
50: columnar
60: gap (inner space)

Claims (10)

Discharge tube,
A pair of electrodes disposed opposite to each other in the discharge tube,
At least one electrode has an internal space,
And the surface area of the inner space is larger than the surface area of the electrode side portion along the axial length of the inner space. The method of claim 1,
The surface area of the said inner space is larger than the surface area of the electrode side part along an electrode axial direction. The method according to claim 1 or 2,
And the inner space has a space formed by rotation of the electrode shaft. The method according to claim 1 or 2,
The electrode has a recess along the electrode axial direction and a columnar portion located at the recess,
The said internal space is formed between the said recessed part and the said columnar part, The discharge lamp characterized by the above-mentioned. The method according to claim 1 or 2,
The said internal space is formed in user tubular shape, The discharge lamp characterized by the above-mentioned. The method according to claim 1 or 2,
And the inner space has a through hole along the vertical direction of the electrode axis. The method according to claim 1 or 2,
The heat dissipation part is provided in the surface part of the said internal space, The discharge lamp characterized by the above-mentioned. The method of claim 4, wherein
The at least one electrode,
It has a 1st solid member which formed the said recessed part, and the 2nd solid member which joined the said 1st solid member or the intermediate member joined with the said 1st solid member, and formed the said columnar part,
And said internal space is formed between said first solid member and said second solid member or said intermediate member. Discharge tube,
A pair of electrodes disposed opposite to each other in the discharge tube,
At least one electrode,
A recess along the electrode axial direction, a columnar portion located at the recess,
An internal space formed between the recessed portion and the columnar portion,
The volume of the columnar portion is larger than the volume of the internal space. A cylindrical recess is formed by the central axis rotation with respect to the columnar front end side solid member which has an electrode front end surface,
About the columnar rear-end solid member, the columnar part smaller in size than the said cylindrical recess part is formed by center axis rotation,
The front end side solid member and the rear end side solid member are combined so that the columnar portion is coaxially arranged with the tubular recess,
In the manufacturing method characterized by forming an electrode including the front end side solid member and the rear end side solid member by solid phase bonding.
The tubular recess and the columnar portion are formed such that the surface area of the inner space formed between the tubular recess and the columnar portion is larger than the surface area of the electrode side portion along the axial length of the inner space. The manufacturing method of the electrode for discharge lamps made into.

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