TWI687968B - Short arc discharge lamp - Google Patents

Abstract

A heat transfer body is enclosed in a sealed space formed on the electrode located vertically above, and is provided in the axis direction of the electrode to extend in the enclosed space, and is formed by a sheet material spanning the radial direction to restrict the convection rotation of the molten heat transfer body The short-arc discharge lamp that moves in the circumferential direction of the limiting body provides convection of the heat transfer body that melts when the lamp is lit, and suppresses the convection from rotating in the circumferential direction in the enclosed space. The pressing force does not act on the inner wall of the enclosed space, especially the inner wall on the rear side of the electrode, to prevent damage to the electrode.

[Solution] The feature is that the plate is provided with a slope on the side edge of the inner wall side of the electrode forming the sealed space; the length from the center axis of the electrode on the upper side of the plate to the radial end, It is shorter than the length from the lower electrode center axis to the radial end.

Description

Short arc discharge lamp

This invention relates to a short-arc type discharge lamp, and particularly to a short-arc type discharge lamp having an electrode in which a heat transfer body is enclosed in a closed space of an electrode body.

In the past, short-arc discharge lamps used as ultraviolet light sources for exposure devices for exposing semiconductor substrates, liquid crystal substrates for liquid crystal displays, printed circuit boards, etc. have been developed to increase their output. Because of the increased output and the increase in the rated power consumption, the current value flowing in the lamp usually increases. Therefore, the amount of electron impact on the electrode also increases, which causes a problem of easy heating and melting.

In addition, the material constituting the electrode, for example, tungsten evaporates, adheres to the inner surface of the arc tube, and becomes black, which also causes a problem that the radiation capability as a lamp decreases.

In order to solve the problems of melting and evaporation of such electrode materials, for example, a short-arc discharge lamp having an electrode structure disclosed in Japanese Patent Application Laid-Open No. 2012-028168 and an electrode structure in which a heat transfer body is enclosed in an internal enclosed space is proposed.

The schematic structure is disclosed in FIGS. 5 and 6, and in FIG. 5, the The arc tube 2 has a short-arc discharge lamp 1 with a pair of electrodes 3 and 4 arranged in the vertical direction. Then, as shown in FIG. 6(A)(B), the electrode body 5 of the upper electrode (in this example, the anode) 4 of the pair of electrodes is formed by the container member 6 and the lid member 7 inside There is a closed space 8 formed.

Then, the sealed space 8 is filled with a material that constitutes the electrode 4, for example, a material having a higher thermal conductivity than tungsten, and a material that melts when the lamp is turned on, such as a heat transfer body M composed of gold, silver, or the like. In addition, the sealed space 8 is filled with an inert gas.

Then, in the sealed space 8 enclosed in the electrode 4 of the heat transfer body M, a plate-shaped restricting body 10 that restricts the convection of the molten heat transfer body M melted during lighting is rotated in the circumferential direction.

With such a structure, the heat transfer body M is melted when the lamp is turned on, and convection in the enclosed space 8 transfers the heat at the front end of the electrode body 5 to the rear end side, thereby reducing the axial direction of the electrode body 15 As a result of the inclination of the temperature, the temperature of the tip can be lowered, thereby exerting the effect of suppressing melting and evaporation of the tip of the electrode.

Then, furthermore, by providing the restricting body 10 in the enclosed space 8, it is possible to restrict and prevent the convection swirling in the circumferential direction when the molten heat transfer body M, which melts at the time of lighting, flows in the enclosed space 8. The temperature change at the same place of the electrode caused by convection-less movement will not occur, and the high-temperature creep deformation according to the temperature change will not occur, so that the function of preventing melting and evaporation at the front end of the electrode is further improved.

However, the heat transfer body is melted due to the lighting of the lamp, but the lamp The tube will solidify when it is extinguished, and will be attached to the inner wall of the closed space. The solidified heat transfer system melts again due to the lighting of the lamp again, but at this time, the heat transfer system starts to melt from the electrode tip side (lower side) which becomes high temperature. At this time, the upper side of the heat transfer body is not yet melted, and until it melts, by melting the heat transfer body, the pressure acts on the inner wall constituting the closed space.

At this time, as shown in FIG. 7, the plate-shaped restricting system is unstable in its posture, and is inclined to one side, and the shoulder is pressed against the inner wall.

The tip side (lower side) of the electrode becomes a higher temperature state and is more ductile, so it is resistant to the pressure of the molten heat transfer body and the pressing action by the restrictor, but behind the electrode at a lower temperature state There is a lack of ductility on the side (upper side), and there may be cracks due to the pressure of the molten heat transfer body and the pressing force of the restricting body. If a crack occurs, it may be used as a starting point to destroy the electrode at a stretch due to the pressure of the molten heat transfer body.

[Prior Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Unexamined Patent Publication No. 2012-028168

In view of the aforementioned problems of the prior art, the present invention encloses a heat transfer body in a closed space formed on an electrode located vertically above, and A short-arc discharge lamp provided with a restrictor that extends in the enclosed space in the axial direction of the electrode and is formed by a plate that spans the radial direction and restricts convection of the molten heat transfer body to rotate in the circumferential direction During convection of the molten heat transfer body when the lamp is turned on, the convection is suppressed from rotating in the circumferential direction in the enclosed space, and the aforementioned plate material prevents the pressing force from acting on the inner wall of the enclosed space, especially the rear side of the electrode The inner wall prevents the electrode from being damaged.

In order to solve the aforementioned problems, the present invention is characterized in that the plate is provided with a slope on the side edge of the inner wall side of the electrode forming the enclosed space; from the center axis of the electrode on the upper side of the plate to the radial direction The length up to the end of is shorter than the length from the center axis of the lower electrode to the end in the radial direction.

In addition, it is characterized by having a parallel portion along the axis direction of the electrode on the lower side of the side edge of the inner wall side of the plate material.

According to the present invention, by adding a slope to the side edge of the inner wall side of the plate-shaped restricting body provided in the enclosed space of the electrode, the length of the upper side is smaller than the length of the lower side in the rear side of the enclosed space of the electrode, Even if the posture of the plate-shaped restricting body changes, it will not abut on the inner wall in the upper side, and the pressing force caused by the plate will not act in the area behind the electrode with a lower temperature and lower ductility. Will produce cracks.

In addition, because there is a parallel portion along the axis direction of the electrode on the lower side of the side edge of the plate-shaped restricting body, the posture of the plate-shaped restricting body in the enclosed space is maintained to a certain extent to suppress tilting and reduce pressure on the electrode pressure.

1‧‧‧Short arc discharge lamp

2‧‧‧luminescent tube

3‧‧‧Cathode

4‧‧‧Anode

5‧‧‧Anode body

6‧‧‧Container components

7‧‧‧ Cover member

8‧‧‧Confined space

10‧‧‧Restricted body

11~17‧‧‧plate

11a‧‧‧Side edge

11b‧‧‧top

11c‧‧‧lower

11d‧‧‧Parallel

12a‧‧‧Side edge

12b‧‧‧top

12c‧‧‧below

12d‧‧‧Parallel

M‧‧‧heat transfer body

X‧‧‧electrode central axis

[FIG. 1] A cross-sectional view (A) of an electrode of a discharge lamp of the present invention, and a cross-sectional view (B) thereof.

[FIG. 2] A front view showing only the restricting body of the present invention.

[Fig. 3] A cross-sectional view of another embodiment.

[Fig. 4] A front view of still another embodiment.

[Figure 5] The previous short arc type discharge lamp.

[Fig. 6] A cross-sectional view (A) of the previous electrode, and a cross-sectional view (B) thereof.

[Fig. 7] A cross-sectional view illustrating the problem of the previous electrode.

FIG. 1 shows the electrode structure of the short-arc discharge lamp of this invention, FIG. 1(A) is its longitudinal cross-sectional view, and FIG. 1(B) is its cross-sectional view.

In the figure, the electrode (anode) 4 has an electrode body 5 composed of a container member 6 and a lid member 7, and a sealed space 8 is formed in the electrode body 5. Then, a heat transfer body M having a higher thermal conductivity than electrode materials such as tungsten is enclosed in the sealed space 8. The heat transfer body M is made of, for example, metal such as gold or silver, has a melting point lower than that of the electrode material, and melts in the enclosed space 8 when the lamp is turned on.

Then, a plate-shaped regulating body 10 is inserted into the sealed space 8 of the electrode 4. The restricting body 10 is conventionally extended in the longitudinal direction on the approximate center axis of the enclosed space 8 and is disposed transverse to the radial direction, and has the same size as the inner diameter of the enclosed space 8 of the electrode 4. Furthermore, the central axis of the restricting body 10 does not necessarily need to be located on the central axis of the electrode 4 in a strict sense.

The detail of the restricting body 10 is disclosed in FIG. 2, FIG. 2(A) is a side view, and FIG. 2(B) is a top view thereof. In this embodiment, the restricting body 10 is made up of plates 11 and 12 crossing each other even in FIGS. 1(B) and 2(B).

Then, the plates 11 and 12 are provided with slopes at the side edges 11a and 12a of the inner wall side of the electrode 4 forming the sealed space 8 from the electrode central axis X of the upper sides 11b and 12b of the plates 11 and 12 to The length L1 up to the radial end is smaller than the length L2 up to the radial end from the electrode center axis X of the lower sides 11c, 12c (L1<L2).

Furthermore, here, the lower side of the plate is located on the side of the front end of the vertically arranged electrode, and the upper side is on the opposite side, that is, on the side of the root side of the electrode.

3 shows a different embodiment of the restricting body 10. In FIG. 3(A), the restricting body 10 is formed by a pair of plates 13 and 14 that cross a slightly T shape according to a plan view. In FIG. 3(B), the restricting body 10 is formed by the plates 15, 16, and 17 that are expanded at three angles at equal angles. The plates 13 to 17 in these conditions also extend in the longitudinal direction of the electrode 4 and span the radial direction, from the center axis X of the upper electrode to the end in the radial direction The length L1 is smaller than the length L2 from the lower electrode center axis X to the radial end (L1<L2).

According to the foregoing embodiment, the plate of the restricting body is provided with a slope in its side edge, and the length L1 of the upper side is smaller than the length L2 of the lower side. Therefore, in the vicinity of the upper side, a large gap is formed between the inner wall surface of the closed space In the lamp, even if the restricting body is inclined due to the influence of the flowing molten heat transfer body, the shoulder above the plate of the restricting body will not abut the pressing wall surface, and the wall surface will not be damaged. In particular, in the initial stage of lighting, when the front end of the electrode becomes high temperature and the solidified heat transfer medium gradually begins to melt, the temperature in the middle and the rear end of the electrode in the axial direction does not become high temperature like the front end, and the metal ductility When it is not in a high state, it is difficult for the corner of the upper side of the plate of the restricting body to push up the inner wall of the container member constituting the closed space. This makes it difficult for the electrode to be destroyed due to thermal stress during lighting.

In addition, even if the lower shoulder of the plate material is in contact with the inner wall surface of the enclosed space, the front end side of the electrode becomes high temperature during lighting, which has sufficient ductility compared to the rear end side, and the risk of damage is low.

Furthermore, the inclination of the side edges of the plate material of the restricting body need not be linear, but may be a curved inclination. In addition, the larger the inclination angle, the less the risk of damage to the inner wall by the restriction body. However, due to this situation, the effect of restricting the convection of the molten heat transfer body in the circumferential direction will also decrease, so for example, the upper length L1 / The lower length L2 is preferably 0.45 to 0.94.

In addition, if the number of plates protruding outward in the radial direction is three or more, three supports can be used when installed in a confined space, so it is more reasonable I want to, but it is acceptable as one piece. Furthermore, the plate material portion where the restrictor intersects may not be point-symmetrical in the cross section orthogonal to the central axis of the electrode.

Furthermore, since the slope of the side edge of the plate is set to move the center of gravity below the restricting body, there is also an effect that the posture is easily stabilized in the enclosed space.

Other embodiments are disclosed in FIG. 4. In this embodiment, parallel portions 11d and 12d along the electrode axis direction are formed in a certain region on the lower side of the side edges 11a and 12a of the plates 11 and 12 constituting the restricting body 10 without a slope.

The other structure is the same as the embodiment shown in FIGS. 1 and 2. The parallel parts 11d and 12d are close to the inner wall of the sealed space 8 with a slight distance between them. If the posture of the restricting body 10 is to be inclined from the state along the central axis of the electrode, the linear extension is restricted by the inner wall Movements can stabilize the posture.

In order to confirm the effect of the present invention, the following experiment was conducted.

The specifications of the lamp are as follows.

<luminescent tube>

Material: Quartz glass

Distance between electrodes: 6mm

Enclosure: Mercury 2.0mg/cc, Argon 100kPa

<anode>

Material: Tungsten

The outer diameter of the body (container member): 25mm

Internal volume of electrode body: 6cm ³

Thickness: 5.5mm

Heat transfer body (silver): 4.7cm ³

Enclosed gas: (argon) 100kPa

<lighting posture>

Use the anode as a vertical light above

<rated>

Rated current: 150A

Rated power: 5kW

<restricted body>

Length: 16mm

The length of the top: 7mm

The length of the lower side: 13.8mm

Thickness: 2mm

<Summary of lighting test>

‧Lighting and light-off test for discharge lamps

‧Light at rated power for 15 minutes-turn off 120 minutes×30 groups

After the test, the electrode was disassembled to confirm the restriction body. As a result, the electrode was not damaged and the electrode was not damaged.

As described above, according to the present invention, a short-arc discharge lamp having an electrode enclosing a heat transfer body in a closed space of an electrode body and provided with an electrode that restricts the convection of the molten heat transfer body to rotate in a circumferential plate-shaped restriction body , The plate constituting the restriction body is provided with a slope on the side edge of the inner wall side of the electrode forming the enclosed space; the length from the center axis of the electrode on the upper side of the plate to the radial end is less than The length from the center axis of the lower electrode to the end in the radial direction is still short, so even if the plate is inclined due to the molten heat transfer body, the upper shoulder of the plate will not abut the inner wall of the pressurized space, Can prevent damage to the electrode.

4‧‧‧Anode

5‧‧‧Anode body

6‧‧‧Container components

7‧‧‧ Cover member

8‧‧‧Confined space

10‧‧‧Restricted body

11‧‧‧Board

12‧‧‧Board

M‧‧‧heat transfer body

Claims (2)

A short-arc discharge lamp is provided with a pair of vertically opposed electrodes inside a light-emitting tube, a heat transfer body is enclosed in an enclosed space formed on an electrode located vertically above, and a shaft extending in the axial direction of the electrode is provided A short-arc discharge lamp in a space formed by a plate extending in the radial direction and restricting the convection of the molten heat transfer body to rotate in the circumferential direction, characterized in that the plate is formed in the closed space The side edge of the inner wall side of the aforementioned electrode is provided with a slope; the length from the center axis of the electrode on the upper side of the plate to the end in the radial direction is longer than the length from the center axis of the electrode on the lower side to the end in the radial direction short. The short-arc discharge lamp as described in item 1 of the patent application range, wherein the lower side of the side edge of the plate material has a parallel portion along the axis direction of the electrode.

Images