JP7210269B2 - Discharge lamps and lighting devices - Google Patents

Description

The present invention relates to a discharge lamp and a lighting device used in an exposure apparatus and the like, and more particularly to a short arc discharge lamp.

2. Description of the Related Art In short-arc discharge lamps used in exposure apparatuses, lighting apparatuses, and the like, the temperature of the electrode supporting rods and the like increases during discharge, and the sealing tube may become overheated. As a result, cracks may occur at the joint between the metal portion and the glass portion inside the sealing tube. Cooling air is blown to the discharge lamp to prevent overheating.

On the other hand, if the discharge tube is cooled excessively, the mercury will not evaporate sufficiently in the period immediately after the start of lighting, and the emission intensity will be weakened. In addition, direct application of the cooling air to the sealing pipe causes a high-temperature portion and a low-temperature portion, resulting in thermal distortion of the sealing pipe. Therefore, in order to maintain the temperature of the sealing tube in a suitable condition from the start of lighting, a substantially cylindrical windbreak plate (arbitrarily called a windbreak tube) is arranged so as to cover the sealing tube (for example, Patent Document 1 reference).

The location of the windbreak tube, including the distance between the sealing tube and the windbreak tube, is determined to control the flow of cooling air along the surface of the discharge tube and sealing tube, and to maintain the temperature of the sealing tube appropriately. must also be carefully set. For example, in Patent Document 2, a windbreak cylinder is placed at a predetermined position in accordance with the shape of the lamp where the sealing tube and the discharge tube are connected, and only a part of the cooling air flows between the sealing tube and the windbreak cylinder. The coolant is poured into the gap to effectively cool the lamp during the period from the start of lighting to the stable lighting state.

JP 2001-135134 A JP 2011-70833 A

However, it is not possible to maintain the sealing tube at an appropriate temperature only by setting the placement location of the windbreak tube, and there is a risk that the sealing tube may become overheated. Therefore, it is necessary to prevent supercooling of the discharge tube from the start of lighting to a stable lighting state, and prevent overheating of the sealing tube during the continuous lighting period after stable lighting.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to prevent overcooling of a discharge tube from the start of lighting to a stable lighting state, and to prevent overheating of a sealed tube during a continuous lighting period after stable lighting. An object of the present invention is to provide a lamp and a lighting device.

The present invention comprises a discharge tube,
a pair of sealing tubes connected to both sides of the discharge tube;
a cylindrical windbreak member that covers at least one of the sealing pipes and prevents the cooling air from hitting the sealing pipe;
a conductive electrode support rod in the sealing tube;
It holds the electrode support rod, is connected to the glass tube welded to the sealing tube, and is connected to the electrode support rod, and electrically connects the metal foil and the electrode support rod arranged along the axial direction. having an annular member;
At least part of the windbreak member is formed with heat reflection suppressing means for suppressing reflection of radiant heat from the sealing tube to the sealing tube ,
A film is formed on the surface of the sealing tube,
The film is not formed on at least part of the region facing the glass tube, and the film is formed on the region facing the annular member on the surface of the sealing tube. It is a discharge lamp that

According to at least one embodiment, by forming the heat reflection suppressing means (alumite treatment) on the windbreak cylinder, the emissivity of the windbreak cylinder increases, and the heat from the sealing tube is absorbed (heat reflection is suppressed). ), the sealing tube temperature can be lowered. When the temperature of the sealing tube is lowered, the temperature of the metal parts inside the sealing tube decreases, and the metal part expands, reducing the force pushing the sealing tube. can be prevented. Note that the effects described herein are not necessarily limited, and may be any effect described herein or an effect different from them.

FIG. 1 is a diagram schematically showing a short arc discharge lamp to which the present invention can be applied. FIG. 2 is a sectional view showing the configuration of the cathode side of one embodiment of the present invention.

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram schematically showing a short arc discharge lamp that is one embodiment. A short-arc discharge lamp 10 is a discharge lamp that can be used as a light source of an exposure device for forming a pattern, and includes a discharge tube (arc tube) 11 made of transparent quartz glass. A cathode 20 and an anode 30 are arranged in the discharge tube 11 so as to face each other with a predetermined gap therebetween.

Sealing tubes 12a and 12b made of quartz glass are integrally formed with the discharge tube 11 so as to face each other on both sides of the tube-shaped discharge tube 11. Both ends of the sealing tubes 12a and 12b are attached to bases. 13a and 13b are connected. The bases 13a, 13b are fixed to the sealing tubes 12a, 12b by, for example, powder adhesive. The discharge lamp 10 is arranged vertically so that the anode 30 is on the upper side and the cathode 20 is on the lower side.

Inside the sealing tubes 12a and 12b, conductive electrode support rods 14a and 14b for supporting a cathode 20 and an anode 30 made of metal are arranged, and are connected via an annular member (metal ring) or a metal foil such as molybdenum. are each connected to a conductive lead rod. The sealing tubes 12a, 12b are welded to the glass tubes, glass members, etc. provided in the sealing tubes 12a, 12b, thereby sealing the discharge space in which mercury and rare gas are enclosed. The lead rod is connected to an external power source, and voltage is applied between the cathode 20 and the anode 30 via the metal ring, metal foil and electrode support rods 14a and 14b. When electric power is supplied to the discharge lamp 10, an arc discharge is generated between the electrodes, and a bright line (ultraviolet light) of mercury is emitted.

Around the discharge lamp 10, a spheroidal reflecting mirror (condensing mirror) (not shown) is arranged to constitute a lighting device. When the lamp is lit, light emitted from the discharge lamp 10 is reflected by the reflecting mirror. The reflected light is condensed at the secondary focal point and guided to the object to be irradiated via an illumination optical system (not shown) or the like. For example, when an illumination device is provided in an exposure device, light is applied to the photosensitive surface of the substrate. Furthermore, cooling nozzles are arranged on the sealing tube 12a side and the sealing tube 12b side of the discharge lamp 10, respectively. and the base 13b are cooled respectively.

The windbreak tubes 40 and 50 as windbreak members made of tubular thin plates are metal tubular members (here, aluminum) that surround the sealing tubes 12a and 12b and extend to the ends of the mouthpieces 13a and 13b. 13b are screwed. For example, the windbreak cylinders 40 and 50 are constructed by combining a pair of half cylinders. The windbreak cylinders 40 and 50 prevent cold air from the cooling nozzles from hitting the sealing tubes 12a and 12b directly, preventing overcooling from the start of lighting to stable lighting, and reducing the temperature of the sealing tubes 12a and 12b during stable lighting. is within an appropriate range. As will be described later, at least a part of the windbreak cylinders 40 and 50 is provided with heat reflection suppressing means for suppressing reflection of radiant heat from the sealing tubes 12a and 12b to the sealing tubes.

Heat insulating films 60 and 70 are formed on the outer surfaces of the joints between the discharge tube 11 and the sealing tubes 12a and 12b. The heat insulating films 60 and 70 are provided to keep the coldest spot temperature high during lighting.

FIG. 2 is a cross-sectional view showing in more detail the configuration including the sealing tube 12a and the base 13a on the cathode 20 side. The discharge tube 11 and the sealing tube 12a are integrally formed, and the shape changes from around the joint with the sealing tube 12a so that the diameter increases from the sealing tube 12a toward the discharge tube 11.

The electrode support rod 14a is inserted through a hollow thick-walled glass tube 31 and an inner metal ring 35 which is an annular member. there is The electrode support rod 14a is held by a glass tube 31, a metal ring 35, and a glass member 32 along the lamp axis. The glass tube 31 and the glass member 32 are welded to the inner surface of the sealing tube 12a.

The inner metal ring 35 is provided between the glass tube 31 and the glass member 32, and the outer metal ring 36, which is an annular member, is provided between the glass member 32 and the outer glass tube 37. there is A disk-shaped disk foil (not shown) may be provided between each member such as between the glass tube 31 and the inner metal ring 35 or between the glass member 32 and the outer metal ring 36 . The lead rod 33 is passed through the outer metal ring 36 and inserted into the sealed end side of the glass member 32 . A plurality of strip-shaped metal foils 34 made of molybdenum or the like are provided on the peripheral surface of the glass member 32 so as to be spaced apart from each other along the peripheral direction, and both ends thereof are connected to metal rings 35 and 36 .

A cylindrical foil (not shown) may be provided on the outer peripheral surface of the inner metal ring 35 to cover the electrode-side end of the metal foil 34 together with the inner metal ring 35 . Moreover, the surface of this foil may be embossed.

A heat insulating film 60 made of a film (metal film) containing platinum, gold, or the like is formed (applied) from the axial end of the discharge tube 11 to the sealing tube 12a so as to cover the outer surface thereof. . At least a portion of the outer surface of the sealing tube 12a facing the glass tube 31 located inside the sealing tube 12a is formed with a region S where no heat insulating film is formed. A heat insulating film 60a is formed separately on the lower side of the region S (here, on the base 13a side). A heat insulating film 60a is formed on the entire surface of the sealing tube 12a facing the metal ring 35. As shown in FIG. Although the heat insulating films 60 and 60a are formed of thin films, their thicknesses are exaggerated for the sake of explanation.

A windbreak cylinder 40 coaxially extends from the mouthpiece 13a to the lower side (opposite direction side) of the end of the glass tube 31 on the side of the discharge tube 11, and is arranged concentrically with the outer surface of the sealing tube 12a at a predetermined distance. It is A facing gap is formed on the inner surface of the windbreak tube 40, and an opening 41 is formed at the end opposite to the sealed end. The position of the end portion of the windbreak tube 40 on the side of the discharge tube 11 is included in the range facing the region S where the heat insulating film 60 is not formed. For example, the opening 41 is positioned near the middle position in the axial direction of the glass tube 31 . That is, the length of the windbreak tube 40 is made shorter than the existing configuration in which the glass tube 31 extends to the end of the glass tube 31 on the discharge tube side.

For example, in the case of a windbreak cylinder made of metal such as aluminum, heat (radiant heat) from the sealing tube may be reflected by the inner surface of the windbreak cylinder, causing the sealing tube to overheat. Therefore, in one embodiment of the present invention, the windbreak tube 40 is anodized to reduce the heat reflected to the sealing tube 12a. An oxide film is formed on the surface by the alumite treatment, which absorbs the incident heat and reduces the heat returning to the sealing tube 12a. As the heat reflection suppressing means, other than the alumite treatment, a treatment for suppressing reflected heat can be employed. For example, surface treatment by mechanical treatment such as blasting, paint system such as radiation paint or coating for heat radiation, and a structure in which a ceramic sheet or plate material is attached can be employed. Since the windbreak tube may be made of materials other than aluminum, the material may be appropriately selected according to the material of the windbreak tube. The means for absorbing radiant heat from the sealing tube 12a may be provided at least on the surface (inner surface) of the windbreak cylinder 40 facing the sealing tube 12a, or may be provided on at least a part of the inner surface.

Such a windbreak cylinder 40 can prevent overheating of the sealing tube and, in turn, lower the temperature of the sealing tube. When the temperature of the sealing tube 12a is lowered, the temperature of the metal part (the inner metal ring 35) inside the sealing tube 12a is lowered, and the metal ring 35 is wound on the outer peripheral surface of the metal foil 34 or the metal ring 35. Since the force (amount of expansion) that presses the foil is reduced, the stress applied to the sealing tube 12a is reduced, and cracks in the sealing tube 12a can be prevented.

In the present embodiment, a region S where no heat insulating film is formed is provided on a portion of the outer surface of the sealing tube 12a that faces the glass tube 31 . As a result, the heat of the electrode support rod 14a inserted through the glass tube 31 can be released without being blocked by the heat insulating film, and as a result, the temperature of the inner metal ring 35 connected to the electrode support rod 14a can be lowered. As the temperature of the metal ring 35 decreases, the metal ring 35 expands, and the force (expansion amount) that presses the metal foil 34 or the foil wound on the outer peripheral surface of the metal ring 35 decreases, and the stress applied to the sealing tube 12a. is also reduced, and cracks in the sealing tube 12a can be prevented. On the other hand, a heat insulating film 60a is formed on the entire surface of the sealing tube 12a facing the inner metal ring 35. As shown in FIG. This keeps the temperature of the sealed tube within an appropriate temperature range.

In addition, by shortening the length of the windbreak cylinder 40, the area that receives heat from the sealing tube 12a and the area that reflects the heat to the sealing tube 12a are reduced, so the temperature of the sealing tube is lowered. be able to. In particular, the end portion of the windbreak tube 40 is located in a range facing the area S where the heat insulating film 60 is not formed, so that the heat (radiant heat) emitted from the sealing tube 12a is absorbed by the heat insulating film and the windbreak tube 40. Since it can be discharged without interruption, the temperature reduction of the electrode supporting rod 14a and the inner metal ring 35 is facilitated. In addition, one or a plurality of ventilation holes may be partially provided on the surface of the windbreak cylinder 40 . Furthermore, the diameter of the windbreak tube 40 may not be constant in the longitudinal direction, but may change along the way (for example, a "convex" shape), or may have a shape in which the diameter changes gradually in a tapered shape. Moreover, although the windbreak cylinder 40 is configured by combining a pair of semi-cylinders, a gap may be formed in the combined portion.

Alkali ions reduce the adhesion between the metal foil 34 and quartz glass in a high temperature state, causing the metal foil 34 to peel off. can be prevented.

As described above, in one embodiment of the present invention, processing is performed to reduce the heat reflected from the inner surface of the windbreak cylinder toward the sealing pipe, the region S where no heat insulating film is formed is formed, and the windbreak cylinder By shortening the longitudinal length of , these effects are synergized, and the temperature of the electrode supporting rod and the metal ring can be further lowered. Moreover, the present invention can exhibit its effects regardless of the shape of the lamp at the joint portion between the sealing tube and the discharge tube.

The sealing tube 12b, the base 13b, the windbreak tube 50, the heat insulating film 70, and the like on the anode 30 side are also configured in the same manner as the cathode 20 side configuration described above. However, at least one of the cathode 20 side and the anode 30 side may be provided with a structure for lowering the temperature of the sealed tube described above. Furthermore, some of the measures are: to reduce the heat reflected from the inner surface of the windbreak cylinder to the sealing pipe, to form a region S where no heat insulating film is formed, and to shorten the length of the windbreak cylinder in the longitudinal direction. may be configured on one electrode side.

Experimental results are shown in Table 1 below. The discharge lamp having the configuration of one embodiment of the present invention is lit at 10.5 kW, and the outer surface of the sealing tube 12a in the region facing the metal foil 34 (corresponding to the middle of the sealing tube 12a. The temperature of the outer surface of the sealing tube (indicated as "metal ring" in Table 1) in the region facing the inner metal ring 35 was measured. A thermocouple was used for temperature measurement. As a comparative example (conventional example), a windbreak cylinder having a length up to the end of the glass tube on the discharge tube side and having no heat reflection suppressing means was attached to seal the area facing the glass tube. A short-arc discharge lamp with a heat insulating film formed on the outer surface of the tube was used. The comparative example was also lit at 10.5 kW and the temperature was measured with a thermocouple.

As shown in Table 1, it was confirmed that the temperature of the discharge lamp according to the embodiment of the present invention decreased at both of the two measurement positions (sealing tube, metal ring). This can prevent cracks and foil peeling of the sealing tube.

An embodiment of the present technology has been specifically described above, but the present invention is not limited to the above-described embodiment, and various modifications are possible based on the technical idea of the present invention. . For example, in the above-described embodiments, the heat reflection suppressing means is formed on the windbreak member, but it is not necessarily required to be formed on the windbreak member. The heat reflection suppressing means may be formed on a tubular member different from the windbreak member, or the tubular member may be made of a material that absorbs heat. In addition, the configurations, methods, processes, shapes, materials, numerical values, etc., given in the above-described embodiments are merely examples, and if necessary, different configurations, methods, processes, shapes, materials, numerical values, etc. may be used. good too.

10... discharge lamp, 11... discharge tube, 12a, 12b... sealing tube,
13a, 13b... Base, 20... Cathode, 30... Anode,
31... glass tube, 32... glass member, 34... metal foil,
35, 36... Metal ring (annular member) 40, 50... Windbreak tube (windbreak member) 60, 70... Thermal insulation film (membrane)

Claims (5)

a discharge tube;
a pair of sealing tubes connected to both sides of the discharge tube;
a cylindrical windbreak member that covers at least one of the sealing tubes and prevents cooling air from hitting the sealing tubes;
a conductive electrode support rod in the sealing tube;
A glass tube that holds the electrode support rod and is welded to the sealing tube is connected to the electrode support rod, and electrically connects the electrode support rod to the metal foil arranged along the axial direction. having an electrically conductive annular member that allows
At least part of the windbreak member is formed with heat reflection suppressing means for suppressing reflection of radiant heat from the sealing tube to the sealing tube,
A film is formed on the surface of the sealing tube,
The film is not formed on at least part of the region facing the glass tube, and the film is formed on the region facing the annular member on the surface of the sealing tube. A discharge lamp, characterized in that 2. The discharge lamp according to claim 1, wherein said heat reflection suppressing means is formed at least on a surface of said windbreak member facing said sealing tube. 2. The discharge lamp according to claim 1 , wherein said heat reflection suppression means is formed of an alumite film. 2. The discharge lamp according to claim 1 , wherein the end portion of the windbreak member is positioned closer to the base than the end portion of the glass tube on the discharge tube side. 5. The discharge lamp according to claim 4 , wherein the end portion of the windbreak member is located in a region facing the glass tube, where the film is not formed.

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