JP2020107419A - Discharge lamp and illumination device - Google Patents

Abstract

To provide a discharge lamp capable of reducing the temperature of a sealed tube, reducing stress applied to the sealed tube, and preventing the occurrence of cracks.SOLUTION: A discharge lamp includes: a discharge lamp; a pair of sealed tubes connected to both sides of the discharge lamp; and a cylindrical windbreak member covering at least one of the sealed tubes. The discharge lamp is characterized to include heat reflection suppression means formed in at least a part of the windbreak member, the heat reflection suppression means suppressing reflection of radiant heat from the sealed tube to the sealed tube.SELECTED DRAWING: Figure 2

Description

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

In a short arc type discharge lamp used for an exposure device, an illumination device, etc., the electrode support rod or the like may become hot during discharge, and the sealed tube may become overheated. As a result, cracks may occur at the joint between the metal portion and the glass portion inside the sealed tube. Cooling air is blown to the discharge lamp to prevent overheating.

On the other hand, if the discharge tube is excessively cooled, mercury does not sufficiently evaporate in the time period just after the start of lighting, and the emission intensity weakens. Further, by directly applying cooling air to the sealed tube, a high temperature portion and a low temperature portion are generated, which causes thermal strain in the sealed tube. Therefore, in order to maintain the temperature of the sealed tube in a suitable state from the start of lighting, a substantially tubular windbreak plate (referred to as a windbreak tube) is arranged so as to cover the sealed tube (for example, Patent Document 1). reference).

The location of the windbreak tube, including the distance between the sealed tube and the windbreak tube, controls the flow of cooling air along the surface of the discharge tube and the sealed tube to maintain the temperature of the sealed tube appropriately. However, it must be set precisely. For example, in Patent Document 2, a windbreak tube is arranged at a predetermined position in accordance with the lamp shape of the connecting portion between the sealing tube and the discharge tube, and only a part of the cooling air is provided between the sealing tube and the windbreak tube. It is poured into a 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, the sealed tube cannot be maintained at an appropriate temperature only by setting the location of the windbreak tube, and the sealed tube may be overheated. Therefore, it is necessary to prevent overcooling of the discharge tube from the start of lighting to the stable lighting state, and to prevent overheating of the sealing tube during the continuous lighting period after stable lighting.

Therefore, an object of the present invention is to prevent overcooling of the discharge tube from the start of lighting to the stable lighting state, and to prevent overheating of the sealing tube during the continuous lighting period after stable lighting. It is to provide a lamp and a lighting device.

The present invention includes a discharge tube, a pair of sealing tubes continuously provided on both sides of the discharge tube, and a tubular windbreak member covering at least one of the sealing tubes, and at least a part of the windbreak member is sealed. The discharge lamp is characterized in that heat reflection suppressing means for suppressing reflection of radiant heat from the stop tube to the sealing tube is formed.
Further, the present invention includes a discharge lamp, a discharge lamp including a pair of sealing tubes continuously provided on both sides of the discharge tube, and a tubular windbreak member covering at least one of the sealing tubes. The illuminating device is characterized in that a heat reflection suppressing means for suppressing reflection of radiant heat from the sealing tube to the sealing tube is formed on at least a part of the above.

According to at least one embodiment, by forming heat reflection suppressing means (alumite treatment) on the windbreak cylinder, the emissivity of the windbreak cylinder is increased and heat from the sealing tube is absorbed (heat reflection is suppressed). Therefore, the temperature of the sealed tube can be lowered. When the temperature of the sealing tube is lowered, the temperature of the metal parts inside the sealing tube decreases, the metal parts expand and the force pushing the sealing tube decreases, so the stress applied to the sealing tube decreases and cracks occur. Can be prevented. Note that the effects described here are not necessarily limited, and may be any one of the effects described in this specification or an effect different from them.

FIG. 1 is a diagram schematically showing a short arc type discharge lamp to which the present invention can be applied. FIG. 2 is a cross-sectional view showing the configuration of the cathode side of the 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 type discharge lamp according to an embodiment. The short arc type discharge lamp 10 is a discharge lamp that can be used as a light source of an exposure apparatus that forms a pattern, and includes a discharge tube (arc tube) 11 made of transparent quartz glass. A cathode 20 and an anode 30 are arranged to face the discharge tube 11 at a predetermined interval.

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

Inside the sealing tubes 12a and 12b, conductive electrode supporting rods 14a and 14b for supporting the metal cathode 20 and the anode 30 are arranged, and a ring-shaped member (metal ring) and a metal foil such as molybdenum are interposed. And electrically connected to the conductive lead rods. The sealing tubes 12a and 12b are welded to a glass tube, a glass member, etc. provided inside the sealing tubes 12a and 12b, and thereby the discharge space in which mercury and a rare gas are sealed is sealed. The lead rod is connected to an external power source, and a voltage is applied between the cathode 20 and the anode 30 via the metal ring, the metal foil, and the electrode supporting rods 14a and 14b. When power is supplied to the discharge lamp 10, arc discharge is generated between the electrodes, and a bright line (ultraviolet light) due to mercury is emitted.

Around the discharge lamp 10, a reflecting mirror (condensing mirror) (not shown), which is a spheroid, is arranged to form an illuminating device. When the lamp is turned on, the light emitted from the discharge lamp 10 is reflected by the reflection mirror. The reflected light is condensed on the secondary focus and guided to the irradiation target through an illumination optical system (not shown). For example, when the illumination device is provided in the exposure device, the photosensitive surface of the substrate is irradiated with light. Further, cooling nozzles are respectively arranged on the sealing tube 12a side and the sealing tube 12b side of the discharge lamp 10, and the cooling tube blows the cooling air into the sealing tube 12a, the base 13a, and the sealing tube 12b. And the base 13b are cooled.

The windbreak tubes 40 and 50 as windbreak members of the tubular thin plate 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 respectively screwed. For example, the windbreak cylinders 40 and 50 are configured by combining a pair of half cylinders. By the windbreak cylinders 40 and 50, the cool air from the cooling nozzle does not directly hit the sealing tubes 12a and 12b, preventing overcooling from the start of lighting to the stable lighting, and the temperature of the sealing tubes 12a and 12b at the stable lighting. To be in the proper range. As will be described later, at least a part of the windbreak cylinders 40, 50 is provided with heat reflection suppressing means for suppressing reflection of radiant heat from the sealing tubes 12a, 12b to the sealing tubes.

Thermal insulation 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 during lighting high.

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

The electrode support rod 14a is inserted into the hollow glass tube 31 and the inner metal ring 35 which is an annular member, and further extends to the cylindrical glass member 32, and is inserted into the glass member 32. There is. The electrode support rod 14a is held by the glass tube 31, the metal ring 35, and the 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 disc-shaped disc foil (not shown) may be provided between the glass tube 31 and the inner metal ring 35 and between the glass member 32 and the outer metal ring 36. The lead rod 33 is inserted through the outer metal ring 36 and is inserted at the sealing end side of the glass member 32. On the peripheral surface of the glass member 32, a plurality of strip-shaped metal foils 34 made of molybdenum or the like are provided apart from each other along the circumferential direction, and both ends thereof are connected to the metal rings 35 and 36.

A cylindrical winding foil (not shown) may be provided on the outer peripheral surface of the inner metal ring 35 to cover the inner metal ring 35 and the electrode side end of the metal foil 34. The surface of this rolled foil may be embossed.

The heat retaining film 60 formed of a film (metal film) containing platinum, gold, or the like is formed (applied) so as to cover the outer surface of the discharge tube 11 from the axial end portion to the sealing tube 12a. .. Further, in the outer surface of the sealing tube 12a, a region S where no heat insulating film is formed is formed in at least a part of a region facing the glass tube 31 located inside the sealing pipe 12a. The heat insulating film 60a is formed separately on the lower side of the region S (here, the side of the base 13a). On the surface of the sealing tube 12a, the heat insulating film 60a is formed on the entire region facing the metal ring 35. The heat insulating films 60 and 60a are formed of thin films, but the thickness is exaggerated for the sake of explanation.

The windbreak tube 40 extends coaxially from the base 13a to the lower side (reverse 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 interval. Has been done. 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 sealing end. The position of the end of the windbreak tube 40 on the side of the discharge tube 11 is included in the range facing the area S where the heat insulating film 60 is not formed. For example, the opening 41 is located near the axially intermediate position of the glass tube 31. That is, the length of the windbreak tube 40 is shorter than that of the existing configuration that extends to the end of the glass tube 31 on the discharge tube side.

For example, in the case of a windbreak tube made of metal such as aluminum, heat (radiation heat) from the sealed tube may be reflected by the inner surface of the windbreak tube, and the sealed tube may be overheated. Therefore, in one embodiment of the present invention, the windbreak tube 40 is subjected to an alumite treatment to reduce the heat reflected to the sealing tube 12a. An oxide film is formed on the surface by the alumite treatment, the incident heat can be absorbed, and the heat returning to the sealing tube 12a can be reduced. As the heat reflection suppressing means, a process for suppressing the reflected heat can be adopted other than the alumite treatment. For example, a surface treatment by mechanical treatment such as blast treatment, a paint system such as a radiation paint or a coating for heat dissipation, and a structure in which a sheet or plate material such as ceramic is attached can be adopted. Since the windbreak cylinder may be made of a material other than aluminum, it may be appropriately selected depending on the material of the windbreak cylinder. The means for absorbing the radiant heat from the sealing tube 12a may be provided at least on the surface (inner surface) of the windbreak tube 40 facing the sealing tube 12a, or may be provided on at least a part of the inner surface.

The windbreak cylinder 40 can prevent the sealed tube from overheating, and can lower the temperature of the sealed tube. When the temperature of the sealing tube 12a is lowered, the temperature of the metal component (inner metal ring 35) in the sealing tube 12a is lowered, and the metal ring 35 is wound around the metal foil 34 or the outer peripheral surface of the metal ring 35. Since the force (expansion amount) for pressing the foil is reduced, the stress applied to the sealing tube 12a is reduced, and the cracking of the sealing tube 12a can be prevented.

In the present embodiment, a region S where the heat insulating film is not formed is provided on a part of the outer surface of the sealing tube 12a in the region facing the glass tube 31. As a result, the heat of the electrode support rod 14a inserted into the glass tube 31 can be released without being blocked by the heat retaining film, and as a result, the temperature of the inner metal ring 35 connected to the electrode support rod 14a can be lowered. The decrease in temperature of the metal ring 35 causes the metal ring 35 to expand and the force (expansion amount) that pushes the metal foil 34 or the winding foil wound on the outer peripheral surface of the metal ring 35 to decrease, and the stress applied to the sealing tube 12a. It is also possible to prevent cracks in the sealing tube 12a. On the other hand, a heat retaining film 60a is formed on the entire surface of the sealing tube 12a facing the inner metal ring 35. As a result, the temperature of the sealed tube is kept in an appropriate temperature range.

Further, by shortening the length of the windbreak tube 40, the area receiving the heat from the sealing tube 12a and the area reflecting the heat to the sealing tube 12a are reduced, so that the temperature of the sealing tube is lowered. be able to. In particular, since the end portion of the windbreak tube 40 is located in a range facing the region S where the heat insulation film 60 is not formed, heat (radiation heat) released from the sealing tube 12a is generated by the heat insulation film and the windbreak tube 40. Since it can be discharged without being blocked, the temperature drop of the electrode support rod 14a and the inner metal ring 35 is promoted. It should be noted that one or a plurality of ventilation holes may be partially provided on the surface of the windbreak tube 40. Furthermore, the diameter of the windbreak tube 40 does not have to be constant in the longitudinal direction, may change in the middle (for example, a “convex” shape), or may have a tapered shape in which the diameter gradually changes. Further, although the windbreak cylinder 40 is configured by combining a pair of semi-cylinders, a gap may be formed in the combined portion.

In a high temperature state, the alkali ions reduce the adhesion between the metal foil 34 and the quartz glass and cause the foil peeling of the metal foil 34. However, according to the present embodiment, the foil peeling occurs due to the temperature decrease of the sealing tube. Can be prevented.

As described above, in one embodiment of the present invention, the process of reducing the heat reflected from the inner surface of the windbreak tube toward the sealing tube is performed, the region S where the heat insulating film is not formed is formed, and the windbreak tube is formed. By shortening the length in the longitudinal direction of these, these effects can be synergized, and the temperature of the electrode support rod and the metal ring can be further lowered. Further, the present invention can exert the effect regardless of the shape of the lamp at the joint portion between the sealing tube and the discharge tube.

The sealing tube 12b on the side of the anode 30, the mouthpiece 13b, the windbreak tube 50, the heat insulating film 70, and the like are also configured in the same manner as the configuration on the side of the cathode 20 described above. However, at least one of the cathode 20 side and the anode 30 side may be provided with the above-described structure for lowering the temperature of the sealed tube. Further, a part of performing a process of reducing heat reflected from the inner surface of the windbreak tube to the sealing tube, forming an area S where the heat retaining film is not formed, and shortening the length of the windbreak tube in the longitudinal direction May be configured on one electrode side.

The experimental results are shown in Table 1 below. The discharge lamp having the configuration of the 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. Temperature), and the temperature of the outer surface of the sealed tube (indicated as "metal ring" in Table 1) in a region facing the inner metal ring 35 was measured. A thermocouple was used for temperature measurement. As a comparative example (conventional example), a windshield having a length up to the end of the glass tube on the side of the discharge tube and having no heat reflection suppressing means is attached to seal the area facing the glass tube. A short arc type discharge lamp having a heat insulating film formed on the outer surface of the tube was used. The comparative example also turned on at 10.5 kW and measured the temperature 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 was lowered at both of the two measurement positions (sealing tube, metal ring). As a result, cracking of the sealing tube and peeling of the foil can be prevented.

Although one embodiment of the present technology has been specifically described above, the present invention is not limited to the above-described one embodiment, and various modifications based on the technical idea of the present invention are possible. .. For example, in the above-described embodiment, the heat reflection suppressing means is formed on the windbreak member, but it is not always necessary to form it 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. Further, the configurations, methods, steps, shapes, materials, numerical values, and the like mentioned in the above-described embodiments are merely examples, and different configurations, methods, steps, shapes, materials, and numerical values may be used as necessary. Good.

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... Windproof cylinder (windproof member), 60, 70... Thermal insulation film (film)

Claims (10)

Discharge tube,
A pair of sealing tubes continuously provided on both sides of the discharge tube,
A tubular windproof member that covers at least one of the sealed tubes,
A discharge lamp, wherein at least a part of the windbreak member is provided with heat reflection suppressing means for suppressing reflection of radiant heat from the sealed tube to the sealed tube. The discharge lamp according to claim 1, wherein the heat reflection suppressing unit is formed on at least a surface of the windbreak member facing the sealing tube. The discharge lamp according to claim 1, wherein the heat reflection suppressing means is formed of an alumite coating. In the sealing tube, a conductive electrode support rod,
Holding the electrode support rod, comprising the sealing tube and a glass tube welded,
A film is formed on the surface of the sealing tube,
4. The discharge lamp according to claim 1, wherein the film is not formed on at least a part of a region facing the glass tube. The sealing tube, the electrode support rod is connected, further comprising a conductive annular member for electrically connecting the metal foil arranged along the axial direction and the electrode support rod,
The discharge lamp according to claim 4, wherein the film is formed in a region facing the annular member on a surface of the sealing tube. The discharge lamp according to claim 4 or 5, wherein an end portion of the windbreak member is located on a side opposite to a discharge tube side end portion of the glass tube. The discharge lamp according to claim 6, wherein an end portion of the windbreak member is located in a region facing the glass tube and in which the film is not formed. Discharge tube,
A pair of sealing tubes continuously provided on both sides of the discharge tube,
Covering at least one of the sealing tubes,
A discharge lamp, comprising: a tubular member that absorbs radiant heat from the sealing tube. Discharge tube,
A pair of sealing tubes continuously provided on both sides of the discharge tube,
A tubular member covering at least one of the sealing tubes,
A discharge lamp, wherein the tubular member is anodized. A discharge lamp, comprising a discharge tube and a pair of sealing tubes that are continuously provided on both sides of the discharge tube,
A tubular windproof member covering at least one sealing tube,
An illumination device, wherein at least a part of the windbreak member is provided with heat reflection suppressing means for suppressing reflection of radiant heat from the sealing tube to the sealing tube.

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