JP2008262846A - Light irradiation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light irradiation device for uniformly cooling a high-pressure discharge lamp. <P>SOLUTION: The light irradiation device comprises a high-pressure discharge lamp, a jacket arranged outside the high-pressure discharge lamp, a reflecting mirror arranged along the high-pressure discharge lamp. The high-pressure discharge lamp is provided with a discharge tube and an outer tube arranged outside the discharge lamp, mercury and a pair of electrode opposed to each other are sealed inside the discharge tube, and gas with a thermal conductivity higher than air is sealed inside the outer tube. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a light irradiation apparatus for irradiating ultraviolet rays.

An apparatus using ultraviolet rays such as a curing process of a resin such as an adhesive or an exposure process of a printed board includes a light irradiation apparatus using a high-pressure discharge lamp. There existed what was described in patent document 1 as such a light irradiation apparatus.
FIG. 9 is an explanatory diagram for the conventional light irradiation device 91 described in Patent Document 1, and is a cross-sectional view of the high-pressure discharge lamp 92 along the tube axis direction.
The light irradiation device 91 includes a high-pressure discharge lamp 92 which will be described later, and a jacket 93 is disposed outward along the longitudinal direction thereof. The jacket 93 includes a cylindrical quartz glass 931 having a small diameter and a cylindrical quartz glass 932 having a large diameter, and is configured such that the central axes of the small diameter quartz glass 931 and the large diameter quartz glass 932 coincide. The Since the jacket 93 functions as a flow path for the cooling water L, the small diameter quartz glass 931 and the large diameter quartz glass 932 are formed so that a flow path is formed between the small diameter quartz glass 931 and the large diameter quartz glass 932. Both ends in the tube axis direction are sealed. Further, in order to supply and discharge the cooling water L to and from the jacket 93, tubular connecting pipes that serve as supply and discharge paths for the cooling water L are connected to both ends of the jacket 93.
Since the high-pressure discharge lamp 92 is disposed so as to extend to the central axis of the jacket 93, an annular support member 94 is disposed on the outer periphery of the high-pressure discharge lamp 92, and the inner peripheral surface of the small-diameter quartz glass 931 is disposed. Supported.
The jacket 93 in which the high-pressure discharge lamp 92 is arranged so as to extend to the central axis is provided with a pair of caps 95 and 96 so as to close both ends in the tube axis direction. One cap 95 is provided with a vent 951 through which the cooling air G for cooling the high-pressure discharge lamp 92 passes. The other cap 96 is provided with an exhaust port 961 for exhausting the cooling air G that has cooled the high-pressure discharge lamp 92.

A high-pressure discharge lamp 92 used in a conventional light irradiation device 91 is shown in FIG. FIG. 10 is an explanatory diagram of a conventional high-pressure discharge lamp 92 and is a cross-sectional view along the tube axis direction of the discharge tube 921.
A light emitting metal such as mercury and a rare gas are enclosed in an interior 926 of a discharge tube 921 made of tubular quartz glass. A pair of electrodes 923 are arranged in the interior 926 of the discharge tube 921 so as to extend to the central axis of the discharge tube 921. Sealing portions 922 from which the external leads 925 protrude are formed at both ends of the discharge tube 921 in the tube axis direction. A metal foil 924 is embedded in the sealing portion 922, and the electrode 923 and the external lead 925 are electrically connected.

  A power supply (not shown) is connected to the external lead 925 of the conventional high-pressure discharge lamp 91. When the lamp 92 is lit, the supplied high-pressure discharge lamp 92 becomes high temperature due to heat generated by the discharge between the electrodes 923. As shown in FIG. 9, the high-pressure discharge lamp 92 that has reached a high temperature is cooled by flowing cooling water L through a flow path inside a jacket 93 disposed outside the high-pressure discharge lamp 92. Further, by blowing air from the vent 951 of one cap 95 as the cooling air G, the high pressure discharge lamp 92 arranged to extend to the central axis of the jacket 93 is cooled by the cooling air G, and the other The cooling air G is discharged from the exhaust port 961 of the cap 96.

Japanese Patent Laid-Open No. 06-267512 Japanese Patent Laid-Open No. 08-148121

  However, if the cooling air G is allowed to flow from the vent 951 of one cap 95 to the exhaust port 961 of the other cap 96, the cooling amount on the outer peripheral surface of the discharge tube 921 will be different. That is, since the cooling air G is introduced from the vent hole 951 of one cap 95, the outer peripheral surface of the discharge tube 921 near the vent hole 951 of one cap 95 has a large amount of cooling. On the other hand, the cooling air G takes heat from the high-pressure discharge lamp 92 and is exhausted from the other cap 96, so that the outer peripheral surface of the discharge tube 921 near the exhaust port 961 of the other end gap 96 is cooled. Is small. Thereby, since the temperature distribution on the outer peripheral surface of the discharge tube 921 is not uniform, one end portion of the high-pressure discharge lamp 91 is excessively cooled, and the light emitting metal such as enclosed mercury is not evaporated, resulting in a decrease in illuminance. There was a thing. In addition, the other end of the high-pressure discharge lamp 91 is not sufficiently cooled and may be damaged by overheating.

Patent Document 2 describes a light irradiation device that cools a high-pressure discharge lamp using cooling water as in Patent Document 1. Patent Document 2 is different from Patent Document 1 in that the cooling air G is not used. The problem of the light irradiation apparatus of patent document 2 is demonstrated using FIG.
Since the light irradiation device 91 of Patent Document 2 is cooled by cooling water flowing through a jacket 93 provided on the outer periphery of the high-pressure discharge lamp 92, the temperature distribution on the outer peripheral surface of the discharge tube 921 due to the cooling air G does not occur. . However, if the amount of light-emitting metal enclosed in the discharge tube 921 is increased or the input power is increased, the amount of heat generated in the discharge tube 921 increases, and the light irradiation device 91 of Patent Document 2 cannot be cooled sufficiently. was there. Therefore, it is conceivable to increase the outer peripheral surface of the discharge tube 921 to be cooled by increasing the outer diameter of the discharge tube 921. However, when the outer peripheral surface of the discharge tube 921 is enlarged, the arc diameter between the electrodes 923 in the discharge tube 921 increases when the lamp 92 is lit, and the function as a linear light source is reduced.

  Then, the objective of this application is providing the light irradiation apparatus which cools a high pressure discharge lamp uniformly.

  A light irradiation apparatus according to a first aspect of the present invention is the light irradiation apparatus comprising a high pressure discharge lamp, a jacket disposed outside the high pressure discharge lamp, and a reflecting mirror disposed along the high pressure discharge lamp. The high-pressure discharge lamp includes a discharge tube and an outer tube disposed outside the discharge tube, and mercury and a pair of opposed electrodes are sealed inside the discharge tube, A gas having a higher thermal conductivity than air is enclosed.

  A light irradiation apparatus according to a second aspect of the present invention is the light irradiation apparatus according to the first aspect, wherein the gas is helium gas or hydrogen gas.

  According to a third aspect of the present invention, there is provided the light irradiation apparatus according to the third aspect, wherein an internal lead that protrudes from each of the discharge tube and the outer tube and is electrically connected to the electrode is provided, and an elastic portion is provided on the internal lead. A light irradiation apparatus according to the first invention, characterized in that:

  In the light irradiation apparatus according to a fourth aspect of the present invention, internal leads projecting from the discharge tube and the outer tube are respectively provided, the gas includes helium gas or neon gas, and the gas includes hydrogen gas or nitrogen. The light irradiation apparatus according to the first aspect, wherein a gas is added.

  The light irradiation apparatus according to a fifth aspect of the present invention is the light irradiation apparatus according to the first aspect, wherein the gas contains helium gas and the outer tube is made of aluminosilicate glass, sapphire, alumina, or YAG. is there.

  A light irradiation apparatus according to a first aspect of the present invention is the light irradiation apparatus comprising a high pressure discharge lamp, a jacket disposed outside the high pressure discharge lamp, and a reflecting mirror disposed along the high pressure discharge lamp. The high-pressure discharge lamp includes a discharge tube and an outer tube disposed outside the discharge tube, and mercury and a pair of opposed electrodes are sealed inside the discharge tube, Since a gas with a higher thermal conductivity than air is enclosed, when the lamp is lit, heat generated by the discharge between the pair of electrodes enclosed in the discharge tube is well transferred to the outer tube by a gas with a higher thermal conductivity than air. The outer tube can be cooled by cooling water that can be heated and that flows through the flow path inside the jacket. For this reason, since the heat generated in the discharge tube can be quickly transferred to the outer tube by a gas having a higher thermal conductivity than air, the high-pressure discharge lamp can be prevented from being damaged due to heat generation.

  In the light irradiation apparatus according to the second invention, since the gas is helium gas or hydrogen gas, the gas enclosed in the outer tube has a thermal conductivity 5 times or more larger than that of air. The internal heat generation can be quickly transferred to the outer tube, and the high pressure discharge lamp can be prevented from being damaged by the heat generation.

  According to a third aspect of the present invention, there is provided the light irradiation apparatus according to the third aspect, wherein an internal lead that protrudes from each of the discharge tube and the outer tube and is electrically connected to the electrode is provided, and an elastic portion is provided on the internal lead. Thus, when the lamp is turned on, the difference between the expansion amount of the discharge tube and the expansion amount of the outer tube cooled by the cooling water due to the discharge between the electrodes can be absorbed by the elastic portion. Therefore, it is possible to prevent damage due to the difference in expansion amount of the high-pressure discharge lamp.

  In the light irradiation apparatus according to a fourth aspect of the present invention, internal leads projecting from the discharge tube and the outer tube are respectively provided, the gas includes helium gas or neon gas, and the gas includes hydrogen gas or nitrogen. When the lamp is turned on when the gas is added, the helium gas or neon gas releases electrons by ionizing when it comes into contact with the internal lead to which voltage is applied, but the energy of the emitted electrons is hydrogen gas or Since it can be extinguished by nitrogen gas, it is possible to prevent discharge between the inner leads inside the outer tube.

  In the light irradiation apparatus according to a fifth aspect of the invention, when the gas contains helium gas and the outer tube is made of aluminosilicate glass, sapphire, alumina, or YAG, the outer tube is heated when the lamp is turned on. The aluminosilicate glass to which aluminum oxide is added has a denser network structure than the network structure of quartz glass made of silicon dioxide, so that helium can be prevented from flowing out. In addition, since the crystal structure of sapphire, alumina, or YAG is not enlarged compared to a glassy material such as quartz glass, helium can be prevented from flowing out of the outer tube made of the crystalline material.

  A light irradiation apparatus according to a first embodiment of the present invention will be described with reference to FIGS.

  FIG.1 and FIG.2 is explanatory drawing of the light irradiation apparatus 1 which concerns on this invention. 1 is a cross-sectional view taken along the longitudinal direction of the high-pressure discharge lamp 2, and FIG. 2 is a cross-sectional view taken along the direction perpendicular to the longitudinal direction of the high-pressure discharge lamp 2 shown in FIG. ). 2, the same components as those shown in FIG. 1 are denoted by the same reference numerals.

In the light irradiation apparatus 1 according to the present invention, a rod-shaped high-pressure discharge lamp 2 having a double tube structure described later is used as a light source. A cylindrical jacket 3 is disposed outside the high-pressure discharge lamp 2 so as to extend the high-pressure discharge lamp 2 around the central axis. As a result, a flow path 31 through which the cooling water L flows is formed along the longitudinal direction of the high-pressure discharge lamp 2 between the outer peripheral surface of the high-pressure discharge lamp 2 and the inner peripheral surface of the jacket 3 as shown in FIG. The jacket 3 is made of, for example, quartz glass that transmits ultraviolet rays.
In order to supply and discharge the cooling water L to and from the flow path 31 formed between the high-pressure discharge lamp 2 and the jacket 3, the cooling water L flow paths 415 and 315 are provided at both ends of the high-pressure discharge lamp 2 and the jacket 3. L-shaped flow path forming members 41 and 42 having 425 are arranged. That is, the flow path 31 formed between the high pressure discharge lamp 2 and the jacket 3 and the flow paths 415 and 425 of the L-shaped flow path forming members 41 and 42 are continuous, and the high pressure discharge lamp 2 and the jacket 3 are connected. It becomes possible to supply and discharge the cooling water L to and from the flow path 31 formed between the two.
The flow path forming members 41, 42 have large-diameter mouth tightening portions 411, 421 and small-diameter mouth tightening portions 412, 422, and each of the mouth tightening portions 411, 412, 421, 422 has an O-ring 413, 414, 423, 424 are provided. The jacket 3 is shorter than the high-pressure discharge lamp 2 in the longitudinal direction of the high-pressure discharge lamp 2. For this reason, the flow path forming members 41 and 42 arranged at both ends of the high-pressure discharge lamp 2 and the jacket 3 hold the outer peripheral surface of the jacket 3 via the O-rings 413 and 423 of the large-diameter fastening portions 411 and 421. The outer peripheral surface of the high-pressure discharge lamp 2 is held and fixed via the O-rings 414 and 424 of the small-diameter fastening portions 412 and 422. Thereby, the flow paths 415 and 425 of the flow path forming members 41 and 42 are continued to the flow path 31 formed between the high-pressure discharge lamp 2 and the jacket 3.

  As shown in FIG. 2, for example, in the longitudinal direction of the high-pressure discharge lamp 2, the light irradiation direction (the direction from the high-pressure discharge lamp 2 toward the mask M in FIGS. 1 and 2) is on the back side of the high-pressure discharge lamp 2. On the other hand, a bowl-shaped reflecting mirror 52 having a reflecting surface 51 having a parabolic cross section along the vertical direction is arranged. The bowl-shaped reflecting mirror 52 is arranged so that its focal point coincides with the central axis of the high-pressure discharge lamp 2 and along the longitudinal direction of the high-pressure discharge lamp 2. The reflecting surface 51 of the reflecting mirror 52 is formed of a multilayer film formed by alternately depositing different reflecting layers such as titania and silica.

  In the light irradiation direction (in FIG. 1 and FIG. 2, the direction from the high-pressure discharge lamp 2 toward the mask M), the mask M placed on the mask stage 6 is arranged. The light emitted from the high-pressure discharge lamp 2 and the light reflected by the reflecting surface 51 pass through the mask M, and are placed on the work stage 7 and applied with a photosensitive agent such as a resist, such as a liquid crystal panel or a semiconductor element. The workpiece W is irradiated.

  FIG. 3 is an explanatory diagram of the high-pressure discharge lamp 2 used in the light irradiation apparatus according to the present invention. 3A is a cross-sectional view taken along the longitudinal direction of the high-pressure discharge lamp 2, and FIG. 3B is a cross-sectional view taken along the direction perpendicular to the longitudinal direction of the high-pressure discharge lamp 2 shown in FIG. BB sectional view of FIG. 3, the same components as those shown in FIG. 1 are denoted by the same reference numerals.

The high-pressure discharge lamp 2 used in the light irradiation apparatus 1 according to the present invention shown in FIGS. 1 and 2 has a double tube structure in which a rod-shaped outer tube 22 is disposed so as to cover the rod-shaped discharge tube 21.
For example, a light emitting metal such as mercury and a rare gas are sealed in the inside 213 of the discharge tube 21 made of quartz glass. At both ends of the discharge tube 21 in the longitudinal direction, a pair of electrodes 23 made of, for example, tungsten are disposed opposite to each other, and first sealing portions 211 and 212 are provided. The first sealing portions 211 and 212 of the discharge tube 21 are formed by, for example, quartz glass pipes extending from both ends in the longitudinal direction of the discharge tube 21 in a molten state and decompressing the inside, that is, It is formed by the shrink seal method. First foils 241 and 242 made of, for example, molybdenum are embedded in the first sealing portions 211 and 212 to electrically connect the electrode 23 and the internal leads 251 and 252.
A rod-shaped outer tube 22 is disposed outside the discharge tube 21 so that the rod-shaped discharge tube 21 extends along the central axis. A gas having a higher thermal conductivity than air, which will be described later, is enclosed in the inside 28 of the outer tube 22, and second sealing portions 221 and 222 are formed at both ends in the longitudinal direction of the outer tube 22. The second sealing portions 221 and 222 include the first sealing portions 211 and 212, the internal leads 251 and 252 protruding from the second sealing portions 221 and 222, and the second sealing portions 221 and 221. Second foils 261 and 262 made of, for example, molybdenum are embedded to electrically connect external leads 271 and 272 protruding from 222.

  The other internal lead 252 protruding from each of the other first sealing portion 212 of the discharge tube 21 and the other second sealing portion 222 of the outer tube 22 is provided with an elastic portion 253 such as a spring.

FIG. 4 is a graph showing thermal conductivity with respect to temperatures of hydrogen (H ₂ ), helium (He), neon (Ne), argon (Ar), and air (air). In the graph of FIG. 4, the horizontal axis represents temperature (° C.) and the vertical axis represents thermal conductivity (W / (m · K)).

As shown in FIG. 4, hydrogen (H ₂ ), helium (He), or neon (Ne) is given as a gas having a higher thermal conductivity than air. Therefore, hydrogen (H ₂ ) gas, helium (He) gas, or neon (Ne) is formed in the space 281 between the inner surface of the outer tube 22 and the outer surface of the discharge tube 21 formed in the inner portion 28 of the outer tube 22. By containing the gas, a gas having a higher thermal conductivity than air is enclosed.
In particular, helium (He) gas or hydrogen (H ₂ ) gas has a thermal conductivity five times or more larger than air. For this reason, helium (He) gas or hydrogen (H ₂ ) gas is sealed in a space 281 between the inner surface of the outer tube 22 and the outer surface of the discharge tube 21, so that the heat generated in the interior 213 of the discharge tube 21 is reduced. Heat is transferred to 22 promptly.

The external leads 271 and 272 protruding from the second sealing portions 221 and 222 of the high pressure discharge lamp 2 are connected to a power source (not shown). When the lamp 2 is lit, the high pressure discharge lamp 2 fed from the power source (not shown) Lights when a discharge occurs between the two. When the lamp 2 is lit, a pump (not shown) is connected to the pair of flow path forming members 41 and 42 shown in FIG. 1, and the cooling water L is supplied to the flow path 415 inside one flow path forming member 41 (not shown) by the pump. Is supplied. The cooling water L is supplied to the flow path 31 between the outer surface of the high-pressure discharge lamp 2 and the inner surface of the jacket 3, which is continuous with the flow path 415 inside the one flow path forming member 41. The cooling water L flowing through the flow path 31 of the jacket 3 is discharged to the flow path 425 inside the other flow path forming member 42 that is continuous with the flow path 31 of the jacket 3.
The discharge tube 21 is heated by the discharge between the electrodes 23 inside the discharge tube 21 of the high-pressure discharge lamp 2. The heat of the discharge tube 21 is transferred to the outer tube 22 by a gas having a higher thermal conductivity than the air enclosed in the space 281 between the outer surface of the discharge tube 21 and the inner surface of the outer tube 22. The outer tube 22 is cooled by the cooling water L flowing on the outer surface of the outer tube 22. As a result, since the discharge tube 21 is cooled, the high-pressure discharge lamp 2 is sufficiently cooled without being damaged.

  Ultraviolet rays are irradiated from the light emitting metal by the discharge between the electrodes 23 inside the discharge tube 21 of the high pressure discharge lamp 2. The ultraviolet rays irradiated from the high-pressure discharge lamp 2 include those directed toward the light irradiation direction and those directed toward the reflecting surface 51. The ultraviolet rays directed toward the reflecting surface 51 are reflected by the reflecting surface 51 and are irradiated in the light irradiation direction. For this reason, the ultraviolet rays from the high-pressure discharge lamp 2 are consequently irradiated in the light irradiation direction. The ultraviolet rays can irradiate the work W placed on the work stage 7 through the mask M in the light irradiation direction.

The discharge tube 21 is supported by internal leads 251 and 252 provided between the first sealing portions 211 and 212 of the discharge tube 21 and the second sealing portions 221 and 222 of the outer tube 22. When the lamp 2 is lit, the discharge tube 21 has a large heating amount due to the influence of the discharge between the electrodes 23, whereas the outer tube 22 is cooled by the cooling water L and thus has a small heating amount. For this reason, since the expansion amount by heating of the discharge tube 21 is large while the expansion amount by heating of the outer tube 22 is small, the discharge tube 21 presses the outer tube 22 through the internal leads 251 and 252. When the difference in expansion amount between the discharge tube 21 and the outer tube 22 is large, the discharge tube 21 or the outer tube 22 may be damaged by pressing. For this reason, by providing the elastic portion 253 on the other internal lead 252, the difference in expansion between the discharge tube 21 and the outer tube 22 can be absorbed by the elastic portion 253, and the discharge tube 21 or the outer tube 22 is pressed. Can prevent damage.
The elastic portion 253 is not limited to the other internal lead 252 but can be prevented from being damaged by pressing the discharge tube 21 or the outer tube 22 if provided on at least one of the pair of internal leads 251 and 252. it can.

  A light irradiation apparatus 1 according to the present invention includes a high-pressure discharge lamp 2, a jacket 3 disposed outside the high-pressure discharge lamp 2, and a reflecting mirror 52 disposed along the high-pressure discharge lamp 2. , The high-pressure discharge lamp 2 includes a discharge tube 21 and an outer tube 22 arranged outside the discharge tube 21, and mercury and a pair of opposed electrodes 23 are enclosed in the inside 213 of the discharge tube 21, The inside 28 of the outer tube 22 is filled with a gas having a higher thermal conductivity than air, so that when the lamp 2 is lit, heat generated by the discharge between the pair of electrodes 23 sealed in the discharge tube 21 is conducted from the air. Heat can be favorably transferred to the outer tube 22 by the gas having a large rate, and the outer tube 22 can be cooled by the cooling water flowing through the flow path 31 inside the jacket 3. For this reason, since heat generated in the inner portion 213 of the discharge tube 21 can be quickly transferred to the outer tube 22 by a gas having a higher thermal conductivity than air, the high-pressure discharge lamp 2 can be prevented from being damaged due to heat generation. .

  In addition, an internal lead 252 that protrudes from each of the discharge tube 21 and the outer tube 22 and is electrically connected to the electrode 23 is provided, and the elastic portion 253 is provided on the internal lead 252, whereby the lamp 1 At the time of lighting, the elastic portion 253 can absorb the difference between the expansion amount of the discharge tube 21 and the expansion amount of the outer tube 22 cooled by the cooling water L due to the discharge between the electrodes 23. Therefore, the high-pressure discharge lamp 2 can be prevented from being damaged due to the expansion amount difference.

In particular, the gas having a higher thermal conductivity than air is helium (He) gas or hydrogen (H ₂ ) gas, so that the gas enclosed in the inside 28 of the outer tube 22 has a thermal conductivity of 5 times or more than that of air. Therefore, the heat generated in the inside 213 of the discharge tube 21 can be quickly transferred to the outer tube 22, and the high-pressure discharge lamp 2 can be prevented from being damaged due to heat generation.

  As a numerical example of the high-pressure discharge lamp 2, the inner diameter R1 of the discharge tube 21 is 20 mm, the outer diameter R2 of the discharge tube is 24 mm, the inter-electrode distance ID is 300 mm, the inner diameter R3 of the outer tube is 27 mm, The outer diameter R4 of the outer tube is φ30 mm, and the tube wall load of the high-pressure discharge lamp 2 is 250 W / cm. The numerical value of the high-pressure discharge lamp 2 is not limited to these, but when the tube wall load is 250 W / cm or more, the tube wall temperature of the discharge tube 21 is as high as 900 ° C. With the configuration of the high-pressure discharge lamp 2, the discharge tube 21 can be effectively cooled, and damage due to heat generation can be prevented.

When the high-pressure discharge lamp 2 used in the light irradiation apparatus 1 has the configuration shown in FIG. 3, a gas containing helium (He) gas or neon (Ne) gas as a gas having a higher thermal conductivity than air is used as the inside 28 of the outer tube 22. When encapsulated, the pair of internal leads 251 and 252 comes into contact with helium (He) gas or neon (Ne) gas. For this reason, when a voltage is applied to the pair of internal leads 251 and 252, helium (He) gas or neon (Ne) gas in contact with the internal leads 251 and 252 is ionized, and the pair of internal leads 251 and 252 is electrically connected. Discharge may occur. When a discharge occurs in the inside 28 of the outer tube 22, it becomes impossible to discharge between the electrodes 23 arranged in the inside 213 of the discharge tube 21.
Therefore, by encapsulating molecules such as nitrogen (N ₂ ) gas in the inside 28 of the outer tube 22, electrons ionized from helium (He) gas or neon (Ne) gas are converted into nitrogen (N ₂ ) gas. collide. As a result, the energy of the electrons is consumed by the movement of vibration or rotation of molecules such as nitrogen (N ₂ ) gas and disappears. Therefore, by adding nitrogen (N ₂ ) gas to a gas containing helium (He) gas or neon (Ne) gas having a higher thermal conductivity than air, it is possible to prevent discharge in the inside 28 of the outer tube 22. it can.
Since about 80% of the gas constituting the air is nitrogen (N ₂ ) gas, the thermal conductivity of the nitrogen (N ₂ ) gas is almost equal to that of air. For this reason, even if nitrogen (N ₂ ) gas is sealed in the inside 28 of the outer tube 22, the gas sealed in the inside 28 of the outer tube 22 does not have a lower thermal conductivity than air.
Since the function of extinguishing electron energy is based on molecules, hydrogen (H ₂ ) gas may be enclosed. Since hydrogen (H ₂ ) gas has a higher thermal conductivity than air, adding hydrogen (H ₂ ) gas to helium (He) gas or neon (Ne) gas does not reduce the thermal conductivity compared to air. .

When the lamp 2 is lit, the outer tube 22 transferred from the discharge tube 21 is heated and expands. At this time, when the outer tube 22 is made of quartz glass, the bond length of the network structure made of silicon dioxide (SiO ₂ ) constituting the quartz glass is increased, and the mesh gap is increased. When helium (He) gas is sealed in the inside 28 of the outer tube 22, helium (He) atoms are small, and therefore helium (He) atoms flow out from a gap in a network structure made of expanded silicon dioxide (SiO ₂ ). Sometimes. For this reason, depending on the heating amount of the outer tube 22 and the lamp 1 lighting elapsed time, the outflow amount of helium (He) atoms increases, and the thermal conductivity of the gas enclosed in the inner portion 28 of the outer tube 22 is remarkably reduced. In some cases, the heat generated inside the tube 213 could not be sufficiently transferred to the outer tube 22.
For example, the outer tube 22 made of aluminosilicate glass is configured by adding aluminum oxide (Al ₂ O ₃ ) to silicon dioxide (SiO ₂ ). When the outer tube 22 is heated and expands, the outer tube 22 made of aluminosilicate glass is added with aluminum oxide (Al ₂ O ₃ ), and thus has a network structure compared to the outer tube 22 made of quartz glass. A finer mesh structure results in a narrower mesh space. Therefore, by configuring the outer tube 22 with aluminosilicate glass, helium (He) atoms can be prevented from flowing out of the outer tube 22 even when the outer tube 22 is heated.
Further, the outer tube 22 is formed of a crystalline member that transmits ultraviolet rays and is made of sapphire (single crystal alumina) or alumina (polycrystalline alumina) mainly composed of YAG (yttrium, aluminum, garnet) or Al ₂ O _3. Thus, the outflow of helium gas sealed in the outer tube 22 can be prevented. This is because a crystalline structure of the crystalline outer tube 22 as described above is not expanded even when heated, as compared with a vitreous material such as quartz glass, so that helium (He) can be prevented from flowing out.

  A second embodiment of the light irradiation apparatus 1 according to the present invention will be described with reference to FIGS.

  FIG. 5 is an explanatory view of the light irradiation apparatus 1 according to the present invention, and is a cross-sectional view along the longitudinal direction of the high-pressure discharge lamp 2. FIG. 6 is an explanatory diagram of the high-pressure discharge lamp 2 used in the light irradiation device 1 of FIG. 6A is a cross-sectional view along the longitudinal direction of the high-pressure discharge lamp 2, and FIG. 6B is a cross-sectional view along the direction perpendicular to the longitudinal direction of the high-pressure discharge lamp 2 of FIG. CC sectional view). 5 and 6, the same components as those shown in FIG. 1 are denoted by the same reference numerals.

  The light irradiation device 1 and the high-pressure discharge lamp 2 used in the light irradiation device 1 shown in FIGS. 5 and 6 are the same as those shown in FIG. 1 in that the outer tube 22 is sealed to the discharge tube 21 without providing the internal lead and the second foil. 3 is different from the light irradiation device 1 shown in FIG. 3 and the high-pressure discharge lamp 2 used therein. As an explanation of FIGS. 5 and 6, differences between FIGS. 1 and 3 will be described.

The high pressure discharge lamp 2 used in the light irradiation apparatus 1 according to the present invention shown in FIG. 5 has a double tube structure in which an outer tube 22 is sealed to a discharge tube 21 as shown in FIG.
First foils 241 and 242 that electrically connect the electrode 23 and the external leads 271 and 272 are embedded in the first sealing portions 211 and 212 of the discharge tube 21. A rod-shaped outer tube 22 is disposed outside the discharge tube 21 so that the rod-shaped discharge tube 21 extends along the central axis. The inside 28 of the outer tube 22 is filled with a gas having a higher thermal conductivity than the air described above. Both ends of the outer tube 22 in the tube axis direction are welded to the first sealing portions 211 and 212 of the discharge tube 21 by being heated by, for example, a burner. As a result, second sealing portions 261 and 262 sealed to the discharge tube 21 are formed at both ends of the outer tube 22 in the tube axis direction.
The discharge tube 21 arranged to extend to the central axis of the outer tube 22 is supported by the outer tube by sealing the second sealing portions 221 and 222 of the outer tube 22.

  The light irradiation apparatus 1 according to the present embodiment also has the same effect as the light irradiation apparatus 1 according to the first embodiment.

  A third embodiment of the light irradiation apparatus 1 according to the present invention will be described with reference to FIGS.

  7 and 8 are explanatory views of the light irradiation apparatus 1 according to the present invention. 7 is a cross-sectional view taken along the longitudinal direction of the high-pressure discharge lamp 2, and FIG. 8 is a cross-sectional view taken along the direction perpendicular to the longitudinal direction of the high-pressure discharge lamp 2 shown in FIG. ). 7 and 8, the same components as those shown in FIG. 1 are denoted by the same reference numerals.

  The light irradiation apparatus 1 shown in FIGS. 7 and 8 is different from the light irradiation apparatus 1 shown in FIGS. 1 and 2 in that a plurality of high-pressure discharge lamps 2 are used. As an explanation of FIGS. 7 and 8, the differences between FIGS. 1 and 2 will be described.

The jacket 3 in this embodiment includes a housing 8 and a light irradiation window 83.
A plurality of (three in FIG. 7 and FIG. 8) high-pressure discharge lamps 2 are disposed in a box-shaped housing 8 made of stainless steel, for example. A plurality (six in FIG. 7 and FIG. 8) of mouth-tightening portions 81 having O-rings 82 are provided on the outer surface of the housing 8 so as to correspond to the high-pressure discharge lamp 2 penetrating the housing 8. The O-ring 82 of the mouthpiece 81 holds and fixes the outer peripheral surface of the outer tube 22 protruding from the housing 8.
Inside the housing 8 is a space 85 through which the cooling water L flows, and a flow path 86 for supplying and discharging the cooling water L is provided in the space 85 so as to be continuous. A bowl-shaped reflecting mirror 52 is provided inside the housing 8 so as to extend between the electrodes 23 of the high-pressure discharge lamp 2. As shown in FIG. 8, the bowl-shaped reflecting mirror 52 has a V-shaped section with respect to each high-pressure discharge lamp 2, and has a saw-shaped section connected to the adjacent reflecting mirror 52.

  The housing 8 has an opening in the light emitting direction from which the reflected light reflected by the reflecting mirror 52 is emitted, and a light irradiation window 83 made of, for example, quartz glass that transmits ultraviolet rays is disposed in the opening. In order to support the light irradiation window 83 at the opening of the housing 8, support bodies 84 held by the housing 8 are provided at four sides and four corners of the light irradiation window 83.

  The light irradiation apparatus 1 according to the present embodiment also has the same effect as the light irradiation apparatus 1 according to the first embodiment.

  The high-pressure discharge lamp 2 described above is not limited to the one in which mercury and a rare gas are enclosed, but a metal halide (iron iodide) is enclosed in the luminescent metal together with mercury, and argon is enclosed in the rare gas. It does not matter if it is

  The discharge tube 21 may be sealed by a pinch seal method in which a quartz glass pipe is melted and crushed.

It is explanatory drawing of the light irradiation apparatus which concerns on this invention. It is explanatory drawing of the light irradiation apparatus which concerns on this invention. It is explanatory drawing of the high pressure discharge lamp used for the light irradiation apparatus which concerns on this invention. It is explanatory drawing about the heat conductivity with respect to the temperature of each gas. It is explanatory drawing of the light irradiation apparatus which concerns on this invention. It is explanatory drawing of the high pressure discharge lamp used for the light irradiation apparatus which concerns on this invention. It is explanatory drawing of the light irradiation apparatus which concerns on this invention. It is explanatory drawing of the light irradiation apparatus which concerns on this invention. It is explanatory drawing of the light irradiation apparatus which concerns on the past. It is explanatory drawing of the light irradiation apparatus which concerns on the past.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light irradiation apparatus 2 High pressure discharge lamp 21 Discharge tube 211 One first sealing part 212 The other first sealing part 213 The inside 22 of the discharge tube The outer tube 221 One second sealing part 222 The other second sealing part Two sealing portions 23 Electrodes 241 One first foil 242 The other first foil 251 One internal lead 252 The other internal lead 253 Elastic portion 261 One second foil 262 The other second foil 271 One One outer lead 272 The other outer lead 28 The inner part 281 of the outer tube 3 The jacket 31 The channel 41 The one channel forming member 411 The large-diameter mouth-clamping part 412 The small-diameter mouth-clamping part 413 The other channel forming member 421 The large-diameter mouth-clamping portion 422 The small-diameter mouth-clamping portion 423 O-ring 424 O-ring 425 Channel 51 Reflecting surface 52 Reflecting mirror 6 Mask stage 7 G 8 Case 81 Clamping portion 82 O-ring 83 Light irradiation window 84 Support body 85 Space 86 Flow path R1 Discharge tube inner diameter R2 Discharge tube outer diameter R3 Outer tube inner diameter R4 Outer tube outer diameter ID Distance between electrodes L Cooling water M Mask W Workpiece

Claims (5)

A high pressure discharge lamp,
A jacket disposed outside the high-pressure discharge lamp;
A reflector disposed along the high-pressure discharge lamp;
In the light irradiation apparatus consisting of
The high-pressure discharge lamp comprises a discharge tube and an outer tube disposed outside the discharge tube,
Inside the discharge tube is sealed mercury and a pair of opposed electrodes,
A light irradiation apparatus characterized in that a gas having a higher thermal conductivity than air is enclosed in the outer tube. The light irradiation apparatus according to claim 1, wherein the gas is helium gas or hydrogen gas. Between the discharge tube and the outer tube are provided internal leads protruding from each,
The light irradiation apparatus according to claim 1, wherein the internal lead is provided with an elastic portion. Between the discharge tube and the outer tube are provided internal leads that protrude from each and electrically connected to the electrodes,
The gas includes helium gas or neon gas;
The light irradiation apparatus according to claim 1, wherein hydrogen gas or nitrogen gas is added to the gas. The gas includes helium gas;
The light irradiation device according to claim 1, wherein the outer tube is made of aluminosilicate glass, sapphire, alumina, or YAG.

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