JPH0539565Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of the Technology] The present invention relates to a short arc type high pressure mercury lamp used in a DC power source.

[Conventional technology]

A short-arc type high-pressure mercury lamp used for lighting with a DC power source has a tungsten anode and a cathode placed within a light bulb made of quartz glass with a high heat-resistant temperature, with a distance between the electrodes of about 1 mm to 6 mm.
Inside, along with the starting gas, mercury is sealed in an amount that increases the vapor pressure from around 1 atm to 50 atm when the lamp is turned on.

Such a discharge lamp has a short distance between electrodes and can provide high brightness, so it is preferably used as a light source for semiconductor exposure equipment. By the way, in recent years, as a light source for semiconductor exposure equipment, semiconductor wafers have become larger and throughput has increased (shorter exposure processing time).
There is a tendency towards higher output due to these factors. Comparatively small output ones are, for example, 102752
-30377) is sufficient, but it was found that further improvements were needed for those with power consumption of 1KW or more.

In other words, as power consumption increases, the current value generally increases, although it depends on the design values of the discharge lamp's current and voltage.As a result, the anode, which is subject to electron collisions, and the internal lead rod of the anode also become thicker. , it needs to be longer. Therefore, it is necessary to change the anode support structure and hermetic sealing structure on the anode side.

Normally, in short arc type discharge lamps, the above structure when the current value increases is as follows:
The one disclosed in Japanese Patent Application Laid-Open No. 141180/1986 is excellent, but it is suitable for rare gas discharge lamps where the discharge luminous gas is xenon, and it is suitable for rare gas discharge lamps such as xenon, and when the luminous gas is liquid or solid at room temperature, such as in mercury lamps. It is considered unsuitable for things that are condensed like this. The reason for this is that as discharge lamps are used repeatedly, mercury and other substances condense deep into the sealing part, making it difficult for them to evaporate when the lamp is used for the first time, and requiring a long time to evaporate. Sometimes, there is a problem that it is difficult to obtain the necessary amount of light immediately. This problem is particularly serious for light sources for semiconductor exposure devices, which have strict requirements for improving productivity.

As mentioned above, as the anode becomes larger and the anode internal lead rod becomes thicker and longer, there are two ways to solve the above problem. One is to make it easier to raise the temperature of the holding part and the sealing part on the anode side, and the other is to make the gap between the holding part and the sealing part as small as possible.

[Purpose of this invention]

The purpose of the present invention is to provide a short arc high-pressure mercury discharge lamp with a relatively large power consumption, especially 500W or more, and a long internal lead rod on the anode side. It is an object of the present invention to provide a discharge lamp configured to minimize the amount of mercury condensed in the lamp.

[Means to achieve the purpose]

In order to achieve the purpose of the present invention, a short arc type high-pressure mercury lamp is composed of a light-emitting bulb surrounding a discharge space, a branch pipe section continuing to both ends of the light-emitting bulb, a cathode and an anode placed opposite each other in the light-emitting bulb, and the cathode and the anode. an internal lead rod supported by the branch pipe, and a hermetically sealed metal foil connecting the rod and an external power source connected to the internal lead rod, and at least on the anode side, the branch A glass pipe made of the same material as the branch pipe part is interposed between the pipe part and the internal lead rod, and the anode is The structure shall provide support.

[Effect]

The inner diameter of the glass pipe should be as close as possible to the outer diameter of the internal lead rod, taking into account the expansion coefficient of the rod.On the other hand, two pieces of metal foil should be used to connect the foil connection part of the rod from both sides. By uniformly reducing the branch pipe portions, the gap between the branch pipe portions having a large inner diameter through which a large electrode is inserted can be minimized.

Furthermore, the area of the branch pipe into which the glass pipe is inserted can be thickened as a result, thereby improving pressure resistance.

〔Example〕

FIG. 1 is an explanatory diagram of an embodiment of a short arc type high pressure mercury lamp according to the present invention.

In the figure, 1 is a light-emitting bulb surrounding a light-emitting space 2, 3 is a cathode, and 4 is an anode. Reference numeral 13 denotes an internal lead rod on the cathode side, and the cathode body is extended as it is to serve also as an internal lead rod. Of course,
A separate cathode may be attached to the tip of this internal lead rod. 14 is an internal lead rod of the anode, which is separate from the large anode 4. 5 and 6 are metal foils made of molybdenum, two of which are used, and a piece of glass 11 is sandwiched between them.
7 and 8 are branch pipe parts, and 9 and 10 are external lead rods. Reference numeral 15 denotes a glass pipe, and in this embodiment, the light bulb 1, the branch pipe parts 7 and 8, and the glass piece 11 are all made of quartz glass.

As mentioned above, in order to reduce the gap 12 formed between the glass pipe 15 and the internal lead rod, the inner diameter of the glass pipe 15 is selected to be as close to the outer diameter of the internal lead rod as possible, or is processed in such a manner. Then, the entire outer circumferential surface of the glass pipe is welded to the inner circumferential surface of the branch pipe section. This welding work is easy if the outer diameter of the glass pipe and the inner diameter of the branch pipe are close to each other. Then, the branch pipes around the metal foil are baked and hardened without using glass pipes, and the metal foil is held tightly to achieve an airtight seal. Therefore, in terms of finishing of the discharge lamp, the branch pipe part is formed with a large diameter part A and a small diameter part B, and the large diameter part A
contributes to improving the pressure resistance of the discharge lamp, but the small diameter part B
This has the practical advantage of requiring only small caps and bases when attaching them.

FIG. 2 is an explanatory diagram of a glass pipe, which discloses an ingenuity in the manufacturing process of the discharge lamp.

As mentioned above, since the glass pipe can slide along the internal lead rod before being welded to the branch pipe section, there is a risk that the glass pipe will become stuck out of position. In order to prevent this, a metal piece 16 of molybdenum or tantalum is welded to a predetermined position of the internal lead rod in advance, and when the metal foil 6 is welded to the end of the internal lead rod after inserting the glass pipe, a slight protrusion may occur. A projecting portion 6a is provided. In this way, if the metal piece 16 and the protruding portion 6a are used to prevent the metal piece 16 from shifting its position, it will be very easy to manufacture.

[Effect of idea]

As can be understood from the above embodiments, the present invention
In short arc type high pressure mercury lamps, the power consumption increases and the anode and the internal lead rod that supports the anode become larger. This minimizes the possibility of the lamp getting into the gap around the rod, and prevents re-lighting, which occurs when the discharge lamp is repeatedly used, especially when the anode is placed at the bottom and the cathode is placed at the top for vertical lighting. The initial mercury vapor pressure deficiency can be quickly resolved. Therefore,
A discharge lamp suitable for reducing processing time used in semiconductor exposure light source devices and the like can be provided.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an embodiment of the short arc type high pressure mercury lamp of the present invention, and FIG. 2 is an explanatory diagram of a glass pipe. In the figure, 1 is a light-emitting bulb, 2 is a discharge space,
3 is a cathode, 4 is an anode, 5 and 6 are metal foils, 7 and 8 are branch pipes, 9 and 10 are external lead rods, 11 is a glass piece, 12 is a gap, and 15 is a glass pipe.

Claims (1)

[Claims for Utility Model Registration] (1) A light-emitting bulb surrounding a discharge space, a branch pipe section continuing to both ends of the light-emitting bulb, a cathode and an anode arranged oppositely in the light-emitting bulb, supporting the cathode and the anode, an internal lead rod held in the branch pipe portion; and a hermetically sealed metal foil connecting the rod and an external power source connected to the internal lead rod, and at least on the anode side, the branch pipe portion and the internal lead rod are connected to each other. A glass pipe made of the same material as the branch pipe part is interposed between the lead rod and the anode is supported using two metal foils sandwiching a glass piece made of the same material as the branch pipe part in a sandwich shape. A short-arc type high-pressure mercury lamp characterized by being used for lighting with the anode positioned downward. (2) The short arc type high-pressure mercury lamp according to item 1, wherein the glass pipe is positioned by a metal piece fixed to an internal lead rod and a protrusion of a hermetically sealed metal foil.