JP5023959B2 - High pressure discharge lamp and high pressure discharge lamp apparatus - Google Patents

Description

  The present invention relates to a high-pressure discharge lamp and a high-pressure discharge lamp device used as a light source for an exposure apparatus such as a semiconductor or a liquid crystal, and in particular, a high-pressure discharge lamp having an outer tube disposed outside an arc tube and a cooling jacket for the high-pressure discharge lamp The present invention relates to a high-pressure discharge lamp device disposed inside.

Currently, for example, an ultraviolet irradiation device is used in a curing process of a resin such as an adhesive or an exposure process of a printed circuit board, and a high-pressure discharge lamp is used as an ultraviolet light source.
FIG. 6 is an explanatory diagram showing an outline of the configuration of a conventional high-pressure discharge lamp device.
As in the invention described in Patent Document 1, this high-pressure discharge lamp device is provided with a cooling jacket 21 including an inner tube 25 and an outer tube 26 outside the arc tube 2 of the high-pressure discharge lamp 1. The cooling is done. The average gap between the arc tube 2 of the high-pressure discharge lamp 1 and the inner tube of the cooling jacket 21 is about 1 mm. In the high-pressure discharge lamp 1, a pair of electrodes are sealed at both ends of a straight tubular quartz glass-made arc tube 2, and mercury is sealed inside. The cooling jacket 21 is made of a transparent material such as cylindrical quartz glass, and has a double tube structure including an inner tube 25 and an outer tube 26. In addition, cooling water circulates from the outside through the connection pipes 27a and 27b provided on the outer circumferences of both ends to cool the adjacent arc tube 2 through the air layer and to radiate heat radiated from the high-pressure discharge lamp 1. Absorb.

In the high-pressure discharge lamp device shown in FIG. 6, the heat generated in the arc tube 2 is cooled only by simple heat conduction of air existing in the gap between the arc tube 2 of the high-pressure discharge lamp 1 and the inner tube 25 of the cooling jacket 21. Since it cannot be transmitted to the jacket 21, the cooling air is passed through the gap between the arc tube 2 of the high-pressure discharge lamp 1 and the inner tube 25 of the cooling jacket 21 to increase the cooling efficiency. However, the temperature of the cooling air that travels through the gap between the arc tube 2 of the discharge lamp and the inner tube 25 of the cooling jacket 21 becomes uneven on the incident side and the exit side, and accordingly, the temperature of the arc tube 2 also becomes non-uniform. turn into.
JP-A-6-267512

  Therefore, it has been proposed to reduce the distance between the arc tube 2 and the cooling jacket 21 in order to cool the arc tube 2 without flowing cooling air through the gap between the arc tube 2 and the cooling jacket 21. By setting the gap between the arc tube 2 and the cooling jacket 21 to an average of about 50 μm, the input is 250 W / cm in the high-pressure discharge lamp 1 having an inside diameter of 3.4 mm (the outside diameter of the arc tube 2 7.4 mm). The inner surface temperature of the arc tube 2 can be cooled to about 800 ° C.

When the high-pressure discharge lamp device is used as a light source for an exposure apparatus such as a semiconductor, the input power input to the lamp is lowered as shown in FIG. Lights up. Since the power saving effect is greater as the standby power is lower, it is desired to reduce the standby power.
However, if the standby power in the standby mode is lowered too much, the inner surface temperature of the arc tube 2 is lowered, and the mercury enclosed in the arc tube 2 is not evaporated. When the mercury has not evaporated, there are problems that the rise time when shifting from the standby mode to the processing mode is delayed, or that the discharge cannot be maintained and it is cut off.

  An object of the present invention is to provide a high-pressure discharge lamp and a high-pressure discharge lamp device capable of high-power lighting that rises in a short period of time and does not stop in the processing mode while reducing standby power in the standby mode.

A first invention of the present application includes an arc tube in which a pair of electrodes are arranged facing each other and mercury is sealed, and a straight tubular outer tube formed outside the arc tube, and the outer tube is formed at both ends of the arc tube. In the high pressure discharge lamp to which is fixed, a convex portion is formed on the outer surface of the arc tube or the inner surface of the outer tube.
According to a second aspect of the present invention, in the first aspect of the present invention, the convex portion is formed by providing a spiral streak on the inner surface of the outer tube.
In the third invention of the present application, in the first invention of the present application, the convex portion is formed by forming the outer surface of the arc tube into a polygonal cross section in a cross section cut perpendicular to the tube axis direction. Features.
In the fourth invention of the present application, in the first to third inventions of the present application, the difference between the inner diameter of the outer tube and the outer diameter of the arc tube is 200 μm or less, and the height of the convex portion is 200 μm or less. It is characterized by that.
In the fourth aspect of the present invention, the high-pressure discharge lamp according to any one of the first to fourth aspects of the present invention is disposed inside the cooling jacket, and the cooling medium flows along the wall surface of the outer tube. It is characterized by that.

  According to the high-pressure discharge lamp and the high-pressure discharge lamp device according to the present invention, the temperature of the coldest spot in the discharge space is raised by forming a convex portion on the inner surface of the outer tube or the outer surface of the arc tube. Therefore, even when the standby power is lowered, the inner surface temperature of the arc tube can be kept high, and the occurrence of unevaporated mercury enclosed in the arc tube can be suppressed. Therefore, it is possible to realize a high-pressure discharge lamp that can be turned on in a short time in the processing mode and can be turned on at a high output without being cut off while reducing standby power in the standby mode.

A first embodiment of the present invention will be described. FIG. 1 is a cross-sectional view illustrating the configuration of a high-pressure discharge lamp device according to the present invention.
The high-pressure discharge lamp device is configured by inserting a high-pressure discharge lamp 1 in which an outer tube 3 is disposed outside the arc tube 2 inside a cooling jacket 21. The cooling jacket 21 is made of a material that transmits ultraviolet rays emitted from the high-pressure discharge lamp 1, for example, quartz glass. At both ends of the cooling jacket 21, a supply flow path 22 for supplying a cooling medium and a discharge flow path 23 for discharging the cooling medium are formed. The supply channel 22 and the discharge channel 23 are generally L-shaped tubular, and hold and fix the cooling jacket 21 and the high-pressure discharge lamp 1. The outer peripheral surface of the cooling jacket 21 is held and fixed via the O-ring by the axially inward closing portion 24a. The outer peripheral surface of the high-pressure discharge lamp 1 is held and fixed via an O-ring by the axially outer closing portion 24b.

  When the high-pressure discharge lamp 1 is turned on, the cooling medium is supplied by a pump (not shown). Cooling of the high-pressure discharge lamp 1 is achieved by circulating a cooling medium at a flow rate of, for example, 5 L (liter) / min. As the cooling medium, water, pure water, reverse osmosis membrane permeated water and the like are suitable.

FIG. 2 is a cross-sectional view illustrating the configuration of the high-pressure discharge lamp 1 of the present invention.
In the high-pressure discharge lamp 1, a pair of rod-shaped electrodes 4 each made of, for example, tungsten are opposed to each other inside a straight tubular arc tube 2 made of, for example, quartz glass and sealed at both ends. Each electrode 4 is connected to one end of a metal foil 5, and an external lead 6 is connected to the other end of the metal foil 5. The metal foil 5 is made of molybdenum and is hermetically embedded in rod-shaped sealing portions 7 formed at both ends of the arc tube 2. The external lead 6 is covered with a supporter 9 outside the sealing portion 7 and has a large diameter. The sealing portion 7 is formed by, for example, a shrink seal method in which both ends of a pipe body, which is a constituent material of the arc tube 2, are melted and the inside is decompressed. The diameter is smaller than the portion corresponding to.

  The high-pressure discharge lamp 1 is configured as, for example, a high-pressure mercury lamp called “capillary lamp”, and the arc tube 2 has, for example, 1 mg / cc or more of mercury, or mercury, iron, cobalt, nickel, lead. At least one of metal halides such as gallium, magnesium, tin, thallium, and manganese is added and sealed, and a rare gas such as argon gas is sealed in an appropriate amount. For example, light including ultraviolet rays having a wavelength of 200 to 450 nm is emitted.

  A straight tubular outer tube 3 made of a transparent material such as cylindrical quartz glass and having a uniform inner diameter in the tube axis direction is formed outside the arc tube 2 of the high-pressure discharge lamp 1. The high pressure discharge lamp 1 is cooled by allowing a cooling medium to flow along the outer surface of the outer tube 3. A base 8 is inserted between the vicinity of both ends of the arc tube 2 and a part of the supporter 9 that covers the external lead 6, and the outer tube 3, and the arc tube 2 and the outer tube 3 are bonded by an adhesive via the base 8. It is airtightly fixed. In the gap between the arc tube 2 and the outer tube 3, an air layer or a gas layer of an appropriate gas is formed.

  Since the arc tube 2 of the high-pressure discharge lamp 1 is configured such that the sealing portion 7 has a smaller diameter than the central portion corresponding to the light emitting region, the sealing portion 7 is close to the outer tube 3 in the central portion. Is separated from the outer tube 3. Therefore, the arc tube 2 of the high-pressure discharge lamp 1 can be sufficiently cooled by the cooling medium at the center of the arc tube 2 to prevent the arc tube 2 from being damaged due to overheating. Furthermore, since the cooling action is weakened in the sealing portion 7 of the arc tube 2 of the high-pressure discharge lamp 1, it is possible to reliably prevent overcooling and to prevent a decrease in illuminance due to non-evaporation of mercury.

A configuration example of the high-pressure discharge lamp 1 is as follows. The inner diameter of the central portion of the arc tube 2 is φ3.4 mm, the outer diameter of the central portion of the arc tube 2 is φ7.4 mm, the outer diameter of the sealing portion 7 is φ6 mm, The total length of the arc tube 2 is 150 mm, the distance between the electrodes 4 is 100 mm, the length of the electrode 4 portion located in the discharge space 10 is 3 mm, and the amount of mercury enclosed is 44 mg / mm ³ . The outer diameter of the outer tube 3 is φ9.5 mm, and the inner diameter of the outer tube 3 is φ7.4 mm.
When the lamp is turned on, the rated voltage of the high-pressure discharge lamp 1 is 2000 V, the rated current is 1.25 A, and the input power is 2500 W.

FIG. 3 is an enlarged sectional view showing a central portion of the high-pressure discharge lamp 1 of the present invention. 3A is an enlarged cross-sectional view when the high-pressure discharge lamp 1 is cut perpendicularly to the tube axis, and FIG. 3B is a view of the contact portion 17 when the high-pressure discharge lamp 1 is cut parallel to the tube axis. It is an expanded sectional view.
The high-pressure discharge lamp 1 has a very narrow gap 14 between the arc tube 2 and the outer tube 3 on average of about 50 μm. Therefore, even if the axial centers of the arc tube 2 and the outer tube 3 are aligned, the dimensional error of the quartz glass For this reason, an area where the arc tube 2 and the outer tube 3 are in contact with each other is generated. As shown in FIG. 3 (a), the arc tube 2 is disposed below the center of the outer tube 3, and a gap d between the lower arc tube 2 and the outer tube 3 is separated from the upper arc tube 2. It is smaller than the gap D with the outer tube 3. Since the outer surface 12 of the lower arc tube 2 has a short distance to the outer tube 3 cooled by the cooling medium, the cooling effect is higher than the outer surface 12 of the upper arc tube 2. Therefore, the inner surface 11 of the arc tube 2 in the contact portion 17 where the outer surface 12 of the arc tube 2 and the inner surface 13 of the outer tube 3 are in contact has the highest cooling effect and becomes the coldest point in the discharge space 10. On the contrary, the inner surface 11 of the arc tube 2 in the portion where the gap D between the outer surface 12 of the arc tube 2 and the inner surface 13 of the outer tube 3 is the largest has the lowest cooling effect and is the most in the discharge space 10. It becomes a hot spot.

  As shown in FIG. 3B, in the cross section cut along the tube axis direction of the high-pressure discharge lamp 1, it is formed so that convex portions 15 are periodically generated on the inner surface 13 of the outer tube 3 in the axial direction. ing. Specifically, the convex portion 15 is formed as a spiral streak on the inner surface 13 of the cylindrical outer tube 3. The height h of the convex part 15 is 10-200 micrometers, and the space | interval P with the adjacent convex part 15 is 0.1-2 mm. Since the convex portion 15 is formed on the inner surface 13 of the outer tube 3, even if the contact portion 17 is enlarged, the outer surface 12 of the arc tube 2 and the inner surface 13 of the outer tube 3 in the convex portion 15. However, a gap is generated between the outer surface 12 of the arc tube 2 and the inner surface 13 of the outer tube 3 at a portion other than the convex portion 15, and an air layer 16 exists. Even at the contact portion 17 where the gap d between the outer surface 12 of the arc tube 2 and the inner surface 13 of the outer tube 3 is the smallest, the outer surface 12 of the arc tube 2 and the inner surface 13 of the outer tube 3 are in close contact. Instead of being in surface contact, the outer surface 12 of the arc tube 2 and the inner surface 13 of the outer tube 3 are in line contact or point contact in contact with the convex portion 15, and there are contact portions and air layer 16 portions.

As shown in FIG. 3A, the gap D between the outer surface 12 of the upper arc tube 2 and the inner surface 13 of the outer tube 3 is the outer surface 12 of the arc tube 2 and the inner surface 13 of the outer tube 3. Because it is opposed to the contact portion 17 with, it becomes the largest. However, since the distance between the outer surface 12 of the arc tube 2 of the contact portion 17 and the inner surface 13 of the outer tube 3 is about the height h of the convex portion 15, the gap of the arc tube 2 in the portion where the gap 14 is the largest. The gap D between the outer surface 12 and the inner surface 13 of the outer tube 3 is also a value obtained by subtracting the height h of the convex portion 15 from the difference between the inner diameter R of the outer tube 3 and the outer diameter r of the arc tube 2 ( (Rr) -h).
Thus, since the gap d is about the height h of the convex portion 15 at the contact portion 17 where the gap d between the outer surface 12 of the arc tube 2 and the inner surface 13 of the outer tube 3 is the smallest, the arc tube 2, the gap D between the outer surface 12 of the outer tube 3 and the inner surface 13 of the outer tube 3 is larger than that when the convex portion 15 is not formed on the inner surface 13 of the outer tube 3. The height 15 of the convex portion 15 is reduced.

  In the contact portion 17 in which the gap 14 serving as the coldest point in the discharge space 10 becomes the smallest, the outer surface 12 of the arc tube 2 and the inner surface 13 of the outer tube 3 are in line contact or point contact in contact with the convex portion 15. Therefore, since the air layer 16 exists between the outer tube 3 and the distance from the outer tube 3 cooled by the cooling medium is increased, the temperature at the coldest point is increased. In addition, since the convex portion 15 is formed to be a spiral line on the inner surface 13 of the cylindrical outer tube 3, no matter where the contact portion 17 is formed on the inner surface 13 of the outer tube 3. The air layer 16 always exists, and the outer surface 12 of the arc tube 2 and the inner surface 13 of the outer tube 3 do not adhere to each other. On the other hand, the distance D between the outer tube 3 and the portion D where the gap 14 serving as the warmest point in the discharge space 10 is the largest is slightly reduced, but there is an air layer between the outer tube 3 and the outer tube 3. Therefore, the temperature at the hottest point hardly fluctuates regardless of the presence or absence of the convex portion 15. Therefore, by forming the convex portion 15 on the inner surface 13 of the outer tube 3, the temperature difference between the coldest point and the hottest point can be reduced.

  By forming the convex portion 15 on the inner surface 13 of the outer tube 3, the temperature of the coldest spot in the discharge space 10 can be raised, so that the temperature of the inner surface 11 of the arc tube 2 can be increased even if the standby power is lowered. It can be kept high, and generation of non-evaporated mercury enclosed in the arc tube 2 can be suppressed. Accordingly, it is possible to realize the high-pressure discharge lamp 1 that can be turned on in a short time in the processing mode and can be turned on at a high output without being cut off while reducing standby power in the standby mode.

FIG. 4 is an explanatory diagram for explaining a method of manufacturing the high-pressure discharge lamp 1 of the present invention.
The high pressure discharge lamp 1 can be manufactured as follows.
First, the rod-shaped electrode 4 and the external lead 6 are electrically connected to both ends of the metal foil 5 to create two electrode 4 structures. An appropriate amount of mercury or the like is sealed in a cylindrical quartz glass tube, and electrode structures are inserted from both sides of the quartz glass tube, and both ends of the quartz glass tube are sealed by a shrink seal method. In this way, the arc tube 2 including the enclosure and the electrode 4 is produced.

  As shown in FIG. 4A, a carbon wire 30 having a diameter of 80 μm is spirally wound around the outer surface 12 of the arc tube 2 at intervals of 2 mm. For convenience, the carbon line 30 is enlarged and drawn on the drawing. On the other hand, a cylindrical quartz glass tube 31 having an inner diameter larger than the outer diameter of the arc tube 2 is prepared, and only one of them is sealed. The arc tube 2 around which the carbon wire 30 is wound is put in a quartz glass tube 31, and the inside of the quartz glass tube 31 is depressurized and rotated. The outer tube 3 is formed by scanning the oxyhydrogen burner in the axial direction and heating from the outside of the quartz glass tube 31 to shrink the quartz glass tube 31. At this time, the outer tube 3 is shrunk until the gap 14 with the arc tube 2 becomes narrower than the carbon wire 30.

  As shown in FIG. 4B, when the outer tube 3 is sufficiently baked, both ends of the outer tube 3 are cut into a cylindrical tube shape with both ends opened. Then, the high-pressure discharge lamp 1 is heated in an electric furnace at 1000 ° C. in an atmospheric pressure atmosphere for 3 hours. The carbon wire 30 is burned off by this heating. The carbon wire 30 present in the gap 14 between the outer tube 3 and the arc tube 2 is eliminated, and a convex portion 15 is formed by providing a spiral line on the inner surface 13 of the outer tube 3. In the cross section cut along the tube axis of the high-pressure discharge lamp 1 as shown, a plurality of convex portions 15 are periodically formed on the inner surface 13 of the outer tube 3 in the tube axis direction. The convex portion 15 formed of a spiral line can be easily formed by winding and processing the carbon wire 30 in this way. Further, when the outer tube 3 is formed by shrinking the quartz glass tube 31 as described above, since the carbon wire 30 also serves as a spacer, the distance between the outer tube 3 and the arc tube 2 can be controlled in a substantially constant pattern. For this reason, a region where the arc tube 2 and the outer tube 3 are in close contact with each other does not occur, the uneven cooling is eliminated, and variations in the high pressure discharge lamp 1 can be suppressed.

Subsequently, a second embodiment of the present invention will be described. FIG. 5 shows a contact portion 17 between the outer surface 12 of the arc tube 2 and the outer surface 12 of the outer tube 3 when the high-pressure discharge lamp 1 is cut perpendicularly to the tube axis in the central portion of the high-pressure discharge lamp 1 of the present invention. FIG.
The high-pressure discharge lamp 1 of the second embodiment is the first except that the inner surface 13 of the outer tube 3 is a smooth surface and the outer surface 12 of the arc tube 2 has a polygonal cross section. It has the same configuration as the high-pressure discharge lamp 1 of the embodiment. About 2nd Embodiment, description of the same structural member as the high pressure discharge lamp 1 of 1st Embodiment is abbreviate | omitted.

  As shown in FIG. 5, the outer surface 12 of the arc tube 2 is cut in a cross section perpendicular to the tube axis direction of the high-pressure discharge lamp 1. 18 is formed. Specifically, the outer surface 12 of the cylindrical arc tube 2 is formed to have a polygonal cross section that is long in the axial direction. It is a polygon having 10 to 60 corners, the height h of the convex portion 18 is 10 to 200 μm, and the interval P between the adjacent convex portions 18 is 0.5 to 2 mm. The thickness of the arc tube 2 is maximized at the portion that is the convex portion 18, and the outer surface 12 of the arc tube 2 and the inner surface 13 of the outer tube 3 are in contact. The thickness of the arc tube 2 is thin at portions other than the convex portion 16, and an air layer 16 is formed between the outer surface 12 of the arc tube 2 and the inner surface 13 of the outer tube 3.

The convex portion 18 where the outer surface 12 of the arc tube 2 and the inner surface 13 of the outer tube 3 are in contact has a short distance to the outer tube 3 cooled by the cooling medium, and the arc tube 2 is directly cooled by the outer tube 3. Is done. The inner surface 11 of the arc tube 2 in the convex portion 18 has the highest cooling effect. On the other hand, the adjacent portion 20 of the convex portion 18 is a distance to the outer tube 3 where the air layer 16 is formed between the outer surface 12 of the arc tube 2 and the inner surface 13 of the outer tube 3 and is cooled by the cooling medium. Will be far away. Since the arc tube 2 is indirectly cooled by the air layer 16, the cooling effect of the inner surface 11 of the arc tube 2 is weakened. Therefore, the temperature of the inner surface 11 of the arc tube 2 in the adjacent portion 20 is not lowered as much as the inner surface 13 of the convex portion 18.
Further, since the convex portion 18 is formed by making the outer periphery of the arc tube 2 have a polygonal cross section, the air layer 16 is always formed regardless of the location of the contact portion 17 on the inner surface 13 of the outer tube 3. It exists and the outer surface 12 of the arc tube 2 and the inner surface 13 of the outer tube 3 do not adhere to each other.

Also in the contact portion 17, the outer surface 12 of the arc tube 2 and the inner surface 13 of the outer tube 3 are not in close contact with each other, but the outer surface 12 of the arc tube 2 and the inner surface 13 of the outer tube 3 are not in contact with each other. Line contact or point contact is made at the convex portion 18, and a contact location and an air layer 16 portion exist. Since the temperature of the inner surface 11 of the arc tube 2 in the adjacent portion 20 having the air layer 16 is higher than the temperature of the inner surface 11 of the arc tube 2 in the convex portion 18, the temperature of the inner surface 11 of the arc tube 2 in the convex portion 18 is increased. The temperature of the inner surface 11 of the arc tube 2 as the entire contact portion 17 can be increased by heating. Therefore, the temperature of the inner surface 11 of the arc tube 2 at the contact portion 17 that is the coldest point in the discharge space 10 can be increased as compared with the case where the convex portion 18 is not formed on the outer surface 12 of the arc tube 2. .
By forming the convex portion 18 on the outer surface 12 of the arc tube 2, the temperature of the coldest spot in the discharge space 10 can be raised, so that the temperature of the inner surface 11 of the arc tube 2 can be increased even if the standby power is lowered. It can be kept high, and generation of non-evaporated mercury enclosed in the arc tube 2 can be suppressed. Accordingly, it is possible to realize the high-pressure discharge lamp 1 that can be turned on in a short time in the processing mode and can be turned on at a high output without being cut off while reducing standby power in the standby mode.

Next, examples will be described.
<Example 1>
A high-pressure discharge lamp apparatus using the high-pressure discharge lamp shown in the first embodiment was created and used as an experiment target. The specifications of the high-pressure discharge lamp used for the experiment are shown below.
Arc tube: made of quartz glass, central part inner diameter φ8 mm, central part outer diameter φ12 mm, sealing part outer diameter: φ6 mm, light emission length 100 mm
Outer tube: Quartz glass, inner diameter φ12.1 mm, outer diameter φ14.1 mm
Convex part: height 50 μm, interval in tube axis direction 2 mm
Electrode: made of tungsten, distance between electrodes: 100 mm, length of electrode part located in discharge space 10: 3 mm
Inclusion material: Mercury 7.5 mg / cc, Argon gas 100 Torr
In addition, the convex part was formed by winding the carbon wire with a diameter of 80 μm on the outer surface of the arc tube in a coil shape at intervals of 2 mm.
It was lit for 30 seconds in the processing mode, then lit for 30 seconds in the standby mode, and lit so that the processing mode and the standby mode were alternated. During the processing mode, the high-pressure discharge lamp was turned on so that the input power was 3000 W (300 W / cm). In the standby mode, the high pressure discharge lamp was lit so that the input power was 2000 W (200 W / cm).
In the cooling jacket, water was circulated as a cooling medium at a flow rate of 5 L / min.
In addition, as a comparison object, a high-pressure discharge lamp 1 having the same specifications as that of the experiment object was prepared, except that no convex portion was formed on the inner surface of the outer tube.

In the high pressure discharge lamp to be tested in which the convex portion was formed on the inner surface of the outer tube, the temperature on the inner surface of the arc tube became 700 ° C. at the contact portion and 1000 ° C. at the maximum portion of the gap in the processing mode. . In the standby mode, the temperature was 540 ° C. at the contact portion and 800 ° C. at the maximum portion of the gap.
In the comparative high-pressure discharge lamp in which no convex portion is formed on the inner surface of the outer tube, the temperature on the inner surface of the arc tube is 550 ° C. at the contact portion and 1000 ° C. at the maximum portion of the gap in the processing mode. It was. In the standby mode, the temperature was 430 ° C. at the contact portion and 800 ° C. at the maximum portion of the gap.
In the high pressure discharge lamp of the experiment subject with the convex portion formed on the inner surface of the outer tube, the temperature of the contact portion serving as the coldest point is 150 ° C. higher in the processing mode than the high pressure discharge lamp of the comparison subject, and the standby mode Then, it became 110 degreeC high.

  When the temperature in the discharge space falls below 400 ° C, the enclosed mercury will not evaporate, causing a delay in the rise time when shifting from the standby mode to the processing mode, and a break that prevents the discharge from being maintained. To do. From the results of this experiment, the high pressure discharge lamp to be tested in which the convex portion is formed on the inner surface of the outer tube has the temperature of the contact portion in the standby mode in which the temperature in the discharge vessel is the lowest during the lighting of the high pressure discharge lamp. It was 540 ° C., and the coldest spot temperature was found to be 140 ° C. higher than 400 ° C. As a result, in the high pressure discharge lamp to be tested in which the convex portion is formed on the inner surface of the outer tube, the input power in the standby mode is made smaller than 200 W / cm so that the temperature of the contact portion in the standby mode further decreases. It was predicted that mercury would not be evaporated even when the lamp was lit under various conditions.

<Experimental example 2>
From the prediction based on the experimental result of Experimental Example 1, the high pressure discharge lamp device to be tested in which the convex portion was formed on the inner surface of the outer tube was turned on with the input power in the standby mode being reduced. The specifications of the high-pressure discharge lamp used as an experiment target were the same as those in Experimental Example 1. The cooling conditions of the high-pressure discharge lamp device were also the same as in Experimental Example 1. The lighting conditions for the high pressure discharge lamp were as follows.
It was lit for 30 seconds in the processing mode, then lit for 30 seconds in the standby mode, and lit so that the processing mode and the standby mode were alternated. During the processing mode, the high-pressure discharge lamp was turned on so that the input power was 3000 W (300 W / cm). In the standby mode, the high pressure discharge lamp was lit so that the input power was 1500 W (150 W / cm).
That is, the lighting conditions of the high-pressure discharge lamp were the same as in Experimental Example 1 except that the input power in the standby mode was lowered.

The high pressure discharge lamp of the test object in which the convex portion was formed on the inner surface of the outer tube did not generate mercury unevaporated even when the standby mode input power was 150 W / cm. Since no non-evaporated mercury was generated, the transition from the standby mode to the processing mode could be maintained with a short rise time. In the processing mode, high output lighting was possible with high input power regardless of the input power value in the standby mode.
Therefore, even if the standby power in the standby mode is lowered, no unevaporated mercury is generated, so that it is possible to realize a high-pressure discharge lamp that can rise from the standby mode to the processing mode in a short time and can be lit at high power without being interrupted in the processing mode. Was confirmed.

According to the result of Experimental Example 1, in the high pressure discharge lamp in which the convex portion is not formed on the inner surface of the outer tube, when the input power is 200 W / cm, the arc tube at the contact portion that becomes the coldest point in the discharge space The inner surface temperature becomes 430 ° C. If the input power value is further reduced, the coldest spot temperature in the discharge space is lowered, and mercury is not evaporated. That is, in the high pressure discharge lamp in which the convex portion is not formed on the inner surface of the outer tube, the minimum value of the input power in the standby mode was 200 W / cm.
On the other hand, from the results of Experimental Example 2, it was confirmed that the high-pressure discharge lamp to be tested in which the convex portion was formed on the inner surface of the outer tube could have the standby mode input power of 150 W / cm. From this, it was found that the input power in the standby mode can be reduced to 75% as compared with the high-pressure discharge lamp according to the prior art in which no convex portion is formed.

Sectional drawing for description which shows the structure of the high pressure discharge lamp apparatus of this invention Sectional drawing for description which shows the structure of the high pressure discharge lamp of this invention The expanded sectional view which shows the center part of the high-pressure discharge lamp of this invention Explanatory drawing for demonstrating the method to manufacture the high pressure discharge lamp of this invention The expanded sectional view which shows the center part of the high-pressure discharge lamp of this invention Explanatory drawing which shows the outline of a structure of the conventional high pressure discharge lamp apparatus. Explanatory diagram showing input power when using a high-pressure discharge lamp

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High pressure discharge lamp 2 Arc tube 3 Outer tube 4 Electrode 14 Crevice 15 Protrusion 16 Air layer 17 Contact part 21 Cooling jacket

Claims (5)

A light emitting tube in which a pair of electrodes are arranged to oppose each other and mercury is sealed, and a straight tubular outer tube formed outside the light emitting tube, and the outer tube is airtightly fixed at both ends of the light emitting tube. In high pressure discharge lamps,
A convex portion is integrally formed on the outer surface of the arc tube or the inner surface of the outer tube in the axial direction, and the outer surface of the arc tube and the inner surface of the outer tube are in contact with each other at the convex portion. High pressure discharge lamp.
The high-pressure discharge lamp according to claim 1, wherein the convex portion is formed by providing a spiral streak on the inner surface of the outer tube. The high-pressure discharge lamp according to claim 1, wherein the convex portion is formed by forming the outer surface of the arc tube into a polygonal cross section in a cross section cut perpendicularly to the tube axis direction. 4. The high-pressure discharge lamp according to claim 1, wherein a difference between an inner diameter of the outer tube and an outer diameter of the arc tube is 200 μm or less, and a height of the convex portion is 200 μm or less. 5. The high pressure discharge lamp device according to claim 1, wherein the high pressure discharge lamp is disposed inside a cooling jacket, and a cooling medium flows along the wall surface of the outer tube. .

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