Irradiation device

Abstract

To provide an irradiation device that can achieve proper cooling of a discharge lamp.SOLUTION: An irradiation device includes: a discharge lamp that has a tube-like light-emitting tube and extends in one direction; a lamp house which has a space where the discharge lamp is provided, one end of which is opened and which has multiple holes arranged side by side in the direction in which the discharge lamp extends on a plane intersecting with the open end; an exhaust part which is connected to the surface opposite to the open end of the lamp house and can exhaust air from the lamp house; and a shutter which can open / close the holes located on the end side of the row in the row of holes.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] Embodiments of the present invention relate to an irradiation device.

Background Art

[0002] There are irradiation devices provided with discharge lamps such as high-pressure mercury lamps and metal halide lamps. Irradiation devices provided with discharge lamps are used, for example, in bonding in a liquid crystal manufacturing process, curing of printing ink, and the like. The discharge lamp has a tubular arc tube and electrodes provided at both ends of the arc tube. In the case of a high-pressure mercury lamp, a rare gas, mercury, and the like are enclosed inside the arc tube. In the case of a metal halide lamp, a rare gas, mercury, metal, halogen elements, and the like are enclosed inside the arc tube.

[0003] In such a discharge lamp, if the temperature of the arc tube becomes too high, blackening of the arc tube progresses due to the enclosed mercury or the like, and it may become impossible to maintain the illuminance. Further, if the temperature of the sealing portion provided at both ends of the arc tube becomes too high, the welded portion of the electrode may be oxidized or the sealing portion may be deformed inside the sealing portion.

[0004] In recent years, miniaturization of the discharge lamp and improvement of the processing ability of the irradiation device have been demanded. When the discharge lamp is miniaturized, the temperature of the arc tube and the sealing portion becomes high. Further, when the power applied to the discharge lamp is increased in order to improve the processing ability of the irradiation device, the temperature of the arc tube and the sealing portion becomes high. Therefore, a technique of flowing air around the arc tube to cool the arc tube has been proposed.

[0005] However, the discharge lamp may be repeatedly lit and extinguished. When the discharge lamp is extinguished, the sealing portion provided with the electrode is cooled faster than the central region of the arc tube. Therefore, mercury vapor and metal halide vapor enclosed inside the arc tube are likely to condense in the vicinity of the end of the arc tube provided with the sealing portion.

[0006] Therefore, when the light is turned on after being turned off, mercury vapor and metal halide vapor will be condensed near the ends of the discharge tube when the light is turned on. However, since the temperature near the ends of the discharge tube is lower than the central region of the discharge tube, the temperature of the condensed mercury and metal halide vapor will not rise to its evaporation temperature easily. As a result, with each repeated switching on and off, the amount of mercury vapor and metal halide vapor inside the discharge tube will decrease, and the intensity of the ultraviolet light generated may decrease over time. Therefore, there was a need for the development of an irradiation device that could properly cool the discharge lamp. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2017-157458 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The problem that this invention aims to solve is to provide an irradiation device that can properly cool a discharge lamp. [Means for solving the problem]

[0009] The irradiation device according to the embodiment includes: a discharge lamp having a tubular discharge tube and extending in one direction; a lamp housing having a space inside in which the discharge lamp is provided, with one end open and a plurality of holes arranged in the direction in which the discharge lamp extends on the surface intersecting the open end; an exhaust section connected to the surface of the lamp housing facing the open end and capable of exhausting the inside of the lamp housing; and a shutter capable of opening and closing the holes located on the end side of the row of holes; A movable part that changes the position of the discharge lamp in at least one of the directions in which the discharge lamp extends and the direction perpendicular to the direction in which the discharge lamp extends; It is equipped with. If the position of the discharge lamp changes due to the moving part, the shutter changes the position in which it closes the hole according to the changed position of the discharge lamp. [Effects of the Invention]

[0010] According to embodiments of the present invention, an irradiation device capable of properly cooling a discharge lamp can be provided. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic cross-sectional view illustrating the irradiation device according to this embodiment. [Figure 2] This is a schematic perspective view of the irradiation device. [Figure 3] This is a schematic cross-sectional view of a discharge lamp. [Figure 4] This is a schematic cross-sectional view illustrating the airflow inside a lamphouse. [Figure 5] This graph illustrates the cooling effect of the holes provided in the lamp housing. [Figure 6] This is a schematic diagram illustrating the position of the shielding portion when a discharge lamp is lit. [Figure 7] This is a schematic diagram illustrating the position of the shielding portion when the discharge lamp is turned off. [Figure 8] This table illustrates the effect of the shutter when a discharge lamp is turned off. [Figure 9] This graph illustrates the effect over time of installing a shutter. [Modes for carrying out the invention]

[0012] The embodiments will be illustrated below with reference to the drawings. In each drawing, similar components are denoted by the same reference numerals, and detailed descriptions will be omitted as appropriate. Figure 1 is a schematic cross-sectional view illustrating the irradiation device 1 according to this embodiment. Figure 2 is a schematic perspective view of the irradiation device 1. As shown in Figures 1 and 2, the irradiation device 1 is provided with, for example, a housing 2, a mounting section 3, a lighting circuit 4, an exhaust section 5, and an ultraviolet irradiation section 6.

[0013] The housing 2, for example, has a box shape. The housing 2 can, for example, have an airtight structure such that particles such as those in a chamber do not enter. Also, depending on the use of the irradiation device 1, the housing 2 can also be one without an airtight structure. For example, the housing 2 may have a framework structure using elongated members. Inside the housing 2, a placement section 3 and an ultraviolet irradiation section 6 can be provided.

[0014] On the placement section 3, an object 100 to be processed can be placed. The placement section 3 can also be provided with a chuck or the like for holding the object 100. Also, the placement section 3 may be one that moves the object 100 in the horizontal direction. For example, the placement section 3 may be an XY table, a conveyor, or the like.

[0015] The lighting circuit 4 is electrically connected to a discharge lamp 61 provided in the ultraviolet irradiation section 6. The lighting circuit 4, for example, has an inverter that converts electric power from an AC power source into high-voltage and high-frequency electric power.

[0016] The exhaust section 5 is connected to a surface 62b of the lamp house 62 that faces the open end. The exhaust section 5 is connected to a hole 62b1 of the lamp house 62, for example, via a duct 51 or the like. The exhaust section 5 can be, for example, a sirocco fan, a blower, or the like. The exhaust section 5 exhausts the inside of the lamp house 62 through the hole 62b1 and introduces air into the inside of the lamp house 62 through the hole 62a1. Details regarding the introduction of air into the inside of the lamp house 62 and the discharge of air from the inside of the lamp house 62 will be described later.

[0017] In addition, elements necessary according to the content of the processing can be appropriately added to the irradiation device 1. For example, when the irradiation device 1 performs an alignment process on an alignment film such as a liquid crystal display element or a viewing angle compensation film by the photo-alignment method, the irradiation device 1 can include a polarizer between the ultraviolet irradiation section 6 (discharge lamp 61) and the placement section 3. The polarizer can be, for example, a wire grid type polarizer.

[0018] The ultraviolet irradiation section 6 is provided with, for example, a discharge lamp 61, a lamp housing 62, a holder 63, a filter 64, and a shutter 65. In Figures 1 and 2, an example is shown where one ultraviolet irradiation unit 6 is provided, but multiple ultraviolet irradiation units 6 can also be provided. When multiple ultraviolet irradiation units 6 are provided, they can be arranged in a direction perpendicular to the tube axis direction of the discharge lamp 61 (the direction in which the discharge lamp 61 extends). In addition, multiple discharge lamps 61 can be provided in a single ultraviolet irradiation unit 6. When multiple discharge lamps 61 are provided, they can be arranged in a direction perpendicular to the tube axis direction of the discharge lamp 61.

[0019] The discharge lamp 61 provided in the ultraviolet irradiation section 6 is not particularly limited as long as it is capable of emitting ultraviolet light. For example, the discharge lamp 61 can be a high-pressure mercury lamp that emits ultraviolet light. Alternatively, the discharge lamp 61 can be a metal halide lamp that emits ultraviolet light. In other words, the discharge lamp 61 can be, for example, a high-intensity discharge lamp. In the following example, we will describe the case where the discharge lamp 61 is a high-pressure mercury lamp.

[0020] As shown in Figures 1 and 2, the discharge lamp 61 is installed inside the lamp housing 62. The discharge lamp 61 extends in one direction inside the lamp housing 62.

[0021] Figure 3 is a schematic cross-sectional view of the discharge lamp 61. As shown in Figure 3, the discharge lamp 61 includes, for example, a discharge tube 61a, an electrode 61b, a conductive foil 61c, an outer lead 61d, a base 61e, and lead wires 61f. The discharge tube 61a has a tubular shape, with a total length (length in the axial direction of the tube) that is longer than the tube diameter. The discharge tube 61a extends in one direction. The discharge tube 61a can be, for example, a cylindrical tube. The discharge tube 61a is formed from a material that has heat resistance and ultraviolet transmittance. The material of the discharge tube 61a can be, for example, quartz, or glass such as soda-lime glass or hard glass.

[0022] A sealing portion 61a1 is provided at each of the ends of the discharge tube 61a in the direction of the tube axis. By providing the sealing portion 61a1, the internal space of the discharge tube 61a can be hermetically sealed. The sealing portion 61a1 can be formed, for example, using a pinch seal method or a shrink seal method.

[0023] A discharge medium is sealed inside the discharge tube 61a. The discharge medium can be, for example, a noble gas and mercury. The noble gas can be, for example, xenon, argon, or a mixed gas of several types of noble gases. The gas pressure (sealing pressure) inside the discharge tube 61a at 25°C can be, for example, 1333 Pa or more. The gas pressure (sealing pressure) inside the discharge tube 61a at 25°C can be determined by the standard conditions of the gas (SATP (Standard Ambient Temperature and Pressure): 25°C, 1 bar). The amount of mercury sealed inside is, for example, about 1 mg to 1000 mg.

[0024] Furthermore, if the discharge lamp 61 is a metal halide lamp, the discharge medium may further include a halogen or a metal for generating ultraviolet light (for example, at least one of iron, tin, indium, bismuth, thallium, or manganese).

[0025] Furthermore, a protective film can be provided on the inner wall of the discharge tube 61a. The protective film is provided, for example, to prevent mercury from reaching the inner wall of the discharge tube 61a. The protective film is, for example, a film containing aluminum oxide or silicon dioxide.

[0026] The electrodes 61b are provided at each of the ends of the discharge tube 61a. The electrodes 61b include, for example, a coil 61b1 and an inner lead 61b2. The coil 61b1 and the inner lead 61b2 can be integrally formed using a linear member. The linear member includes, for example, tungsten or a rhenium-tungsten alloy.

[0027] The coil 61b1 is located in the internal space of the discharge tube 61a. For example, the coil 61b1 is made by winding a linear member in a spiral shape. One end of the inner lead 61b2 is connected to the coil 61b1 in the internal space of the discharge tube 61a. The other end of the inner lead 61b2 is connected to the conductive foil 61c inside the sealing portion 61a1. The inner lead 61b2 and the conductive foil 61c can be connected, for example, by laser welding or resistance welding.

[0028] The conductive foil 61c is provided inside the sealing portion 61a1. One conductive foil 61c is provided for each sealing portion 61a1. The planar shape of the conductive foil 61c is, for example, a rectangle. The conductive foil 61c is formed from, for example, molybdenum foil.

[0029] At least one outer lead 61d can be provided for each conductive foil 61c. The outer lead 61d is linear in shape. One end of the outer lead 61d is connected to the conductive foil 61c inside the sealing portion 61a1. For example, one end of the outer lead 61d can be laser-welded or resistance-welded to the conductive foil 61c. The other end of the outer lead 61d is exposed to the outside of the sealing portion 61a1. The lighting circuit 4 is electrically connected to the outer lead 61d. The outer lead 61d is formed from, for example, a wire containing molybdenum.

[0030] The nozzle 61e is provided at each of the ends of the discharge tube 61a in the axial direction of the tube. The nozzle 61e can be formed from, for example, an insulating material. The nozzle 61e can be formed from, for example, steatite, aluminum oxide, etc.

[0031] The lead wires 61f can be provided at each of the ends on both sides of the discharge tube 61a. The lead wires 61f are electrically connected to the ends of the outer leads 61d that are exposed from the sealing portion 61a1. The lead wires 61f are electrically connected to the electrodes 61b via the outer leads 61d and the conductive foil 61c. The lead wires 61f are electrically connected, for example, to a lighting circuit 4 provided outside the irradiation device 1.

[0032] In the discharge lamp 61, a discharge occurs between the electrodes 61b. The electrons generated by the discharge collide with mercury atoms sealed inside the discharge tube 61a. When electrons and mercury atoms collide, the mercury atoms receive energy from the electrons, generating ultraviolet light with a peak wavelength of approximately 253.7 nm. The generated ultraviolet light is irradiated to the outside of the discharge tube 61a. In other words, the discharge lamp 61 is an example of a long-arc type high-brightness ultraviolet lamp.

[0033] The lamp housing 62 is, for example, located inside the casing 2. The lamp housing 62 is box-shaped, with an open end on the mounting section 3 side. The lamp housing 62 has a space inside in which the discharge lamp 61 is installed.

[0034] The inner wall of the lamp housing 62 can also be a reflective surface that reflects ultraviolet light emitted from the discharge lamp 61. For example, the inner wall of the lamp housing 62 can be provided with a film containing a highly reflective metal. The inner wall of the lamp housing 62 can also be polished to a glossy surface. When viewed from the axial direction of the discharge lamp 61, the contour of the inner wall of the lamp housing 62 can include a curve. The curve can be, for example, part of a circle, part of an ellipse, or a parabola. In other words, the lamp housing 62 can also function as a reflector.

[0035] A portion of the ultraviolet light emitted from the discharge lamp 61 is directly directed onto the object 100. Furthermore, if the lamp housing 62 functions as a reflector, the ultraviolet light emitted from the discharge lamp 61 and incident on the inner wall of the lamp housing 62 is reflected back towards the object 100. Having a reflector function in the lamp housing 62 improves the efficiency of ultraviolet light utilization.

[0036] The external shape of the lamp housing 62 can be, for example, a rectangular parallelepiped. Multiple holes 62a1 can be provided on both sides 62a of the lamp housing 62 that intersect with the open end (the end on the mounting section 3 side) and are perpendicular to the tube axis direction of the discharge lamp 61. Multiple holes 62a1 can be arranged in a line along the tube axis direction of the discharge lamp 61. In the direction perpendicular to the tube axis direction of the discharge lamp 61, the multiple holes 62a1 provided on one side 62a can be positioned opposite the multiple holes 62a1 provided on the other side 62a. The number of multiple holes 62a1 provided on one side 62a can be the same as the number of multiple holes 62a1 provided on the other side 62a. The number of multiple holes 62a1 provided on one side 62a can be appropriately changed according to the length in the tube axis direction of the discharge lamp 61. The pitch dimension (center-to-center distance) of the multiple holes 62a1 can be, for example, about 20 mm to 100 mm.

[0037] There are no particular limitations on the shape of the hole 62a1. The shape of the hole 62a1 can be, for example, a circle, an ellipse, an elongated hole, a quadrilateral, or other polygon.

[0038] Here, reducing the area of ​​the hole 62a1 increases the airflow velocity introduced through the hole 62a1. A faster airflow velocity increases the amount of air that directly reaches the discharge lamp 61 and makes it easier to push away the hotter air surrounding the discharge lamp 61. Therefore, the cooling efficiency can be improved. However, if the area of ​​the hole 62a1 is made too small, the flow resistance increases, and the airflow rate introduced through the hole 62a1 may become too low. Therefore, the area of ​​the hole 62a1 should be, for example, 80 mm².2 ~2000mm 2 It can be set to a certain extent. If the hole 62a1 is circular, the diameter dimension of the hole 62a1 can be, for example, about 10 mm to 50 mm.

[0039] A slit-shaped hole 62b1 extending in the direction of the axial direction of the discharge lamp 61 can be provided in the ceiling surface 62b of the lamp housing 62, facing the end of the lamp housing 62 on the mounting section 3 side. The hole 62b1 serves as an exhaust port connected to the exhaust section 5. The air inside the lamp housing 62 is heated by the heat from the discharge lamp 61. As the temperature rises inside the lamp housing 62, it tends to collect towards the ceiling surface 62b of the lamp housing 62. Therefore, if the hole 62b1, which serves as an exhaust port, is provided in the ceiling surface 62b, it becomes easier to discharge the hot air inside the lamp housing 62. By discharging the hot air, the discharge lamp 61 can be cooled efficiently.

[0040] Furthermore, if the hole 62b1 extends in the axial direction of the discharge lamp 61, it becomes easy to make the hole 62b1 have a larger area than the total area of ​​the multiple holes 62a1 that serve as air intakes. If the area of ​​the hole 62b1 can be increased, the flow resistance will decrease, making it easier to discharge the air inside the lamp housing 62 through the hole 62b1.

[0041] When viewed from a direction perpendicular to the ceiling surface 62b of the lamp housing 62, the hole 62b1 can be positioned to overlap with the discharge lamp 61. In this case, it is preferable that the center line of the hole 62b1 overlaps with the tube axis of the discharge lamp 61. In this way, the airflow that flows around the discharge lamp 61 and is exhausted from the hole 62b1 can be made symmetrical with respect to the tube axis of the discharge lamp 61 (see Figure 4 described later). Therefore, it is possible to suppress temperature unevenness in the discharge lamp 61.

[0042] At least one hole 62b1 can be provided. The lamp house 62 illustrated in Figure 2 is provided with one hole 62b1 extending in the direction of the tube axis of the discharge lamp 61. When only one hole 62b1 is provided, the length of the hole 62b1 in the direction of the tube axis of the discharge lamp 61 can be, for example, about the same as the length of the hole 62b1 in the direction of the tube axis of the discharge lamp 61. The length (width dimension) of the hole 62b1 in the direction perpendicular to the tube axis of the discharge lamp 61 can be, for example, larger than the tube diameter of the discharge tube 61a. In this way, it becomes easier to discharge the air inside the lamp house 62 through the hole 62b1.

[0043] It is also possible to provide multiple holes 62b1 aligned in the axial direction of the discharge lamp 61. However, providing a single hole 62b1 extending in the axial direction of the discharge lamp 61 results in lower flow resistance compared to providing multiple holes 62b1, making it easier to discharge air from inside the lamp housing 62.

[0044] Figure 4 is a schematic cross-sectional view illustrating the airflow G inside the lamphouse 62. As shown in Figure 4, the distance L1 (mm) between the center of the hole 62a1 provided on the side surface 62a of the lamp housing 62 and the end of the lamp housing 62 on the mounting section 3 side can be made smaller than the distance L2 (mm) between the tube axis of the discharge lamp 61 and the end of the lamp housing 62 on the mounting section 3 side. In this way, it becomes easier to bring the air G introduced into the lamp housing 62 through the hole 62a1 to the vicinity of the end of the discharge lamp 61 on the mounting section 3 side. Therefore, it becomes easier to cool the entire discharge lamp 61.

[0045] Furthermore, by positioning the holes 62a1 on the side surface 62a of the lamp housing 62 and the holes 62b1 on the ceiling surface 62b of the lamp housing 62 as described above, the airflow G inside the lamp housing 62 can be made symmetrical with respect to the tube axis of the discharge lamp 61, as shown in Figure 4. Therefore, temperature unevenness in the discharge lamp 61 can be suppressed.

[0046] Figure 5 is a graph illustrating the cooling effect provided by the holes 62a1 and 62b1 in the lamp housing 62. As can be seen from Figure 5, if holes 62a1 and 62b1 are provided, the entire discharge lamp 61 can be cooled efficiently.

[0047] Furthermore, as can be seen from Figure 5, the temperature in the central region of the discharge lamp 61 is higher than the temperature in the end regions. Therefore, the pitch dimension of the holes 62a1 located in the central region of the discharge lamp 61 may be made smaller than the pitch dimension of the holes 62a1 located in the end regions of the discharge lamp 61. In this way, the airflow rate reaching the central region of the discharge lamp 61 can be increased, thereby lowering the temperature in the central region of the discharge lamp 61.

[0048] Furthermore, the area of ​​the hole 62a1 located at a position corresponding to the central region of the discharge lamp 61 can be made larger than the area of ​​the hole 62a1 located at a position corresponding to the end region of the discharge lamp 61. In this way, the airflow rate reaching the central region of the discharge lamp 61 can also be increased. However, if the area of ​​the hole 62a1 is made too large, the airflow velocity introduced into the lamp housing 62 through the hole 62a1 may decrease, potentially reducing the airflow rate reaching the central region of the discharge lamp 61. Therefore, when changing the area of ​​the hole 62a1 located at a position corresponding to the central region of the discharge lamp 61, it is preferable to keep the area of ​​the hole 62a1 within the range described above. The number, pitch, area, and arrangement of holes 62a1 can be determined as appropriate through experiments and simulations.

[0049] As shown in Figures 1 and 2, a pair of holders 63 may be provided. A pair of holders 63 may be provided at each of the two ends of the discharge lamp 61. The holders 63 can, for example, hold the base 61e of the discharge lamp 61. The holder 63 can also be provided on a pair of movable parts 63a. The pair of movable parts 63a change the position of the pair of holders 63, and consequently the position of the discharge lamp 61, in at least one of the directions of the axial direction of the discharge lamp 61 and the direction perpendicular to the axial direction of the discharge lamp 61. The pair of movable parts 63a may be equipped with, for example, an air cylinder or a solenoid, or they may be equipped with a control motor such as a servo motor, and their movable position may be controllable. In addition, the movable position of the pair of movable parts 63a may be adjusted by an operator or the like.

[0050] If a movable part 63a is provided, the optical design center (center position of the irradiation area) of the discharge lamp 61 can be changed. For example, by changing the center position of the irradiation area of ​​the discharge lamp 61 according to variations in the processing of the object 100, variations in processing can be reduced.

[0051] The filter 64 is plate-shaped and is provided at the end of the lamp housing 62 on the mounting portion 3 side. The filter 64 blocks the opening of the lamp housing 62. Ultraviolet light emitted from the discharge lamp 61 is irradiated onto the object 100 via the filter 64.

[0052] Here, since the emission spectrum of the discharge lamp 61 is broad, ultraviolet light and visible light are emitted from the discharge lamp 61. For this reason, a filter 64 can be provided in the irradiation device 1. The filter 64 ensures that ultraviolet light in a predetermined wavelength range is irradiated onto the object 100, depending on the application of the irradiation device 1 and the type of treatment. For example, when performing sterilization treatment on the object 100, it is preferable that UVC (ultraviolet light with a wavelength of 100 nm to 280 nm) is irradiated onto the object 100. For example, filter 64 can be a bandpass filter that transmits ultraviolet light in a predetermined wavelength range but does not transmit ultraviolet light or visible light outside of that range.

[0053] Furthermore, the object 100 may release a gas containing components of the object 100. If the gas released from the object 100 enters the lamp house 62, deposits containing components of the object 100 may adhere to the outer surface of the discharge lamp 61 (discharge tube 61a). If deposits adhere to the outer surface of the discharge lamp 61 (discharge tube 61a), the illuminance of the discharge lamp 61 in the axial direction may vary. Also, if deposits adhere to the inner wall of the lamp house 62, the illuminance of ultraviolet light reflected from the inner wall of the lamp house 62 may vary. If the illuminance of ultraviolet light varies, the quality of the treated object 100 may deteriorate. In addition, depending on the application of the irradiation device 1 and the type of treatment, it may be sufficient to simply irradiate the object 100 with ultraviolet light.

[0054] Therefore, the filter 64 can also be formed from a material that transmits ultraviolet light, for example. For example, the filter 64 can be made from quartz or glass. The glass can be, for example, soda-lime glass containing sodium oxide or hard glass. By providing such a filter 64, a wide range of ultraviolet light emitted from the discharge lamp 61 can be irradiated onto the object 100.

[0055] Furthermore, whether the filter 64 is a bandpass filter or a filter that transmits a wide range of ultraviolet light, it is possible to suppress the gas emitted from the object 100 from entering the inside of the lamp house 62.

[0056] Furthermore, whether the filter 64 is a bandpass filter or a filter that transmits a wide range of ultraviolet light, the heat generated by the illumination of the discharge lamp 61 can be suppressed from being transferred to the object 100. Therefore, the object 100 can be prevented from being heated and the gas containing components of the object 100 can be suppressed.

[0057] As explained in Figure 5, if holes 62a1 and 62b1 are provided in the lamp housing 62, it is possible to suppress the temperature of the discharge lamp 61 (discharge tube 61a) from becoming too high. Therefore, it is possible to suppress the blackening of the discharge tube 61a due to mercury or other substances sealed inside the discharge tube 61a, which would otherwise make it impossible to maintain the illumination level. In addition, it is possible to suppress the temperature of the sealing part 61a1 from becoming too high, which would cause oxidation of the welded area of ​​the electrode 61b inside the sealing part 61a1 or deformation of the sealing part 61a1.

[0058] In this case, the discharge lamp 61 may be repeatedly switched on and off. As can be seen from Figure 5, the temperature of the end region of the discharge lamp 61 is lower than the temperature of the central region. Therefore, when the discharge lamp 61 is switched off, the end region of the discharge tube 61a cools down faster than the central region of the discharge tube 61a. Since mercury vapor and metal halide vapor are sealed inside the discharge tube 61a, these vapors tend to condense in the end region of the discharge tube 61a, which cools down quickly. Therefore, when the lamp is switched on after being switched off, the mercury vapor and metal halide vapor will be condensed near the end of the discharge tube 61a when the lamp is switched on. However, since the temperature near the end of the discharge tube 61a is lower than the central region of the discharge tube 61a, the temperature of the condensed mercury and metal halide does not easily rise to the evaporation temperature. Therefore, each time the light is turned on and off, the amount of mercury vapor and metal halide vapor inside the discharge tube 61a decreases, which may cause the intensity of the ultraviolet light generated to decrease over time.

[0059] Furthermore, since the evaporation temperature of metal halides is higher than that of mercury, if metal halide vapor is sealed inside the discharge tube 61a, the intensity of the generated ultraviolet light may decrease prematurely. Furthermore, if condensed mercury or metal halides enter the gap between the sealing portion 61a1 and the inner lead 61b2, it becomes even more difficult to evaporate them.

[0060] Therefore, the irradiation device 1 is equipped with a shutter 65. As shown in Figure 2, the shutter 65 is provided on the side surface 62a of the lamp housing 62. The shutter 65 opens and closes some of the multiple holes 62a1 provided on the side surface 62a of the lamp housing 62. For example, in a row of multiple holes 62a1 arranged in the axial direction of the discharge lamp 61, the shutter 65 opens and closes the holes 62a1 located at the end of the row. In other words, when the discharge lamp 61 is turned off, the shutter 65 closes the hole 62a1 located at the end of the row. When the discharge lamp 61 is turned on, the shutter 65 opens the hole 62a1 located at the end of the row.

[0061] The shutter 65 has, for example, a shielding portion 65a and a movable portion 65b. The shielding portion 65a is plate-shaped and can be formed from a heat-resistant material such as metal. The movable part 65b can be provided, for example, on the side surface 62a of the lamp house 62. The movable part 65b moves the shielding part 65a along the side surface 62a of the lamp house 62. For example, the movable part 65b moves the shielding part 65a in at least one of the directions in which the multiple holes 62a1 are aligned, and in a direction perpendicular to the direction in which the multiple holes 62a1 are aligned. The movable part 65b can also pivot or rotate the shielding part 65a. The movable part 65b may be equipped with, for example, an air cylinder or a solenoid, or it may be equipped with a control motor such as a servo motor so that its movement position can be controlled.

[0062] Figure 6 is a schematic diagram illustrating the position of the shielding portion 65a when the discharge lamp 61 is lit. When the discharge lamp 61 is lit, as shown in Figure 6, the movable part 65b moves the shielding part 65a away from the multiple holes 62a1 so that all of the holes 62a1 are open. Once all of the holes 62a1 are open, air is introduced into the lamp housing 62 through all of the holes 62a1. As a result, the entire discharge lamp 61 can be efficiently cooled by the introduced air.

[0063] Figure 7 is a schematic diagram illustrating the position of the shielding portion 65a when the discharge lamp 61 is turned off. When the discharge lamp 61 is turned off, as shown in Figure 7, the movable part 65b moves the shielding part 65a toward the multiple holes 62a1, closing the holes 62a1 located at the end of the row of holes 62a1. Note that the holes 62a1 do not necessarily have to be closed to an airtight seal. Furthermore, one hole 62a1 may be closed entirely, or only a part of one hole 62a1 may be closed. In other words, it is sufficient to close at least a part of one hole 62a1.

[0064] In this case, the shielding portion 65a can be used to close a hole 62a1 located near the end of the discharge tube 61a. For example, a hole 62a1 located within a distance L3 (mm) from the connection point between the discharge tube 61a and the sealing portion 61a1 towards the center of the discharge tube 61a can be closed by the shielding portion 65a. For example, the distance L3 (mm) can be approximately 0 mm to 100 mm.

[0065] Furthermore, as mentioned above, the position of the discharge lamp 61 may change due to the movement of the moving part 63a. When the position of the discharge lamp 61 changes, the shutter 65 can change the position at which it closes the holes 62a1 according to the changed position of the discharge lamp 61. For example, the shutter 65 can change the number or range of holes 62a1 that are closed by the shielding part 65a. For example, as mentioned above, if the moving part 65b is equipped with a control motor such as a servo motor, the number or range of holes 62a1 that are closed by the shielding part 65a can be changed by changing the movement position of the shielding part 65a.

[0066] When the hole 62a1 located near the end of the discharge tube 61a is closed by the shielding portion 65a, it becomes difficult for air to reach the vicinity of the end of the discharge tube 61a. As a result, the temperature near the end of the discharge tube 61a does not decrease easily. If the temperature near the end of the discharge tube 61a does not decrease easily, mercury vapor and metal halide vapor do not condense easily in the vicinity of the end of the discharge tube 61a.

[0067] Furthermore, when the hole 62a1 located near the end of the discharge tube 61a is closed, the airflow velocity of the air introduced into the lamp housing 62 through the open hole 62a1 increases. As a result, the air introduced into the central region of the discharge lamp 61 (discharge tube 61a) can reach it more easily, making it easier for mercury vapor and metal halide vapor to condense in the central region of the discharge tube 61a.

[0068] When the discharge lamp 61 is lit, as illustrated in Figure 5, the temperature in the central region of the discharge tube 61a becomes higher than the temperature near the ends of the discharge tube 61a, making it easier to evaporate the mercury and metal halides that have condensed in the central region of the discharge tube 61a.

[0069] Furthermore, by condensing mercury vapor and metal halide vapor in the central region of the discharge tube 61a, it is possible to suppress the condensed mercury and metal halide from getting into the gap between the sealing portion 61a1 and the inner lead 61b2 and becoming less likely to evaporate.

[0070] Therefore, even if the light is repeatedly switched on and off, the decrease in the amount of mercury vapor and metal halide vapor inside the discharge tube 61a can be suppressed. If the amount of mercury vapor and metal halide vapor is stable, the decrease in the illuminance of the generated ultraviolet light over time can be suppressed.

[0071] Figure 8 is a table illustrating the effect of the shutter 65 when the discharge lamp 61 is turned off. Figure 9 is a graph illustrating the effect over time when shutter 65 is installed.

[0072] As mentioned above, if the shutter 65 is not provided, air will also be introduced through the hole 62a1 located near the end of the discharge tube 61a. As a result, air will reach the vicinity of the end of the discharge tube 61a, and the temperature T2 in that vicinity will decrease. However, as mentioned above, the temperature T1 in the central region of the discharge tube 61a will remain high. Therefore, as shown in Figure 8, the temperature difference T1 in the central region of the discharge tube 61a and the temperature T2 near the end of the discharge tube 61a become large.

[0073] Because the temperature T2 near the end of the discharge tube 61a is low and the temperature difference is large, mercury vapor and metal halide vapor tend to condense near the end of the discharge tube 61a. Furthermore, because the temperature T2 near the end of the discharge tube 61a is low, the condensed metal halides and other substances are less likely to evaporate, or they may enter the gap between the sealing portion 61a1 and the inner lead 61b2, making evaporation even more difficult.

[0074] As a result, as shown in Figure 9, the amount of mercury vapor and metal halide vapor inside the discharge tube 61a decreases with each cycle of switching on and off, causing the intensity of the generated ultraviolet light to decrease over time.

[0075] In contrast, if a shutter 65 is provided, the shielding portion 65a can close the hole 62a1 located near the end of the discharge tube 61a, thereby increasing the temperature T2 near the end of the discharge tube 61a, as shown in Figure 8. Furthermore, as mentioned above, closing the hole 62a1 located near the end of the discharge tube 61a increases the airflow velocity introduced from the hole 62a1 located in the central region of the discharge tube 61a. As a result, the temperature T1 in the central region of the discharge tube 61a can be lowered. In addition, the difference between the temperature T1 in the central region of the discharge tube 61a and the temperature T2 near the end of the discharge tube 61a can be reduced. For example, as can be seen in Figure 8, when the discharge lamp 61 is turned off, the shutter 65 closes the hole 62a1 located at the end of the row, thereby making it possible to keep the temperature difference T1 in the central region of the discharge tube 61a and the temperature T2 near the end of the discharge tube 61a below 50°C.

[0076] Because the temperature T2 near the end of the discharge tube 61a is high and the temperature difference is small, mercury vapor and metal halide vapor are less likely to condense near the end of the discharge tube 61a. Therefore, it is possible to suppress the condensed metal halides from getting into the gap between the sealing portion 61a1 and the inner lead 61b2 and becoming less likely to evaporate. Also, because the temperature T2 near the end of the discharge tube 61a is high, the condensed metal halides evaporate more easily. Therefore, even if the light is repeatedly switched on and off, it is possible to suppress the decrease in the amount of mercury vapor and metal halide vapor inside the discharge tube 61a.

[0077] As a result, the amount of mercury vapor and metal halide vapor is stabilized, which suppresses the decrease in the intensity of ultraviolet light over time, as shown in Figure 9.

[0078] Although several embodiments of the present invention have been illustrated above, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. Furthermore, the embodiments described above can be implemented in combination with each other. [Explanation of symbols]

[0079] 1 Irradiation device, 2 Housing, 3 Mounting section, 4 Lighting circuit, 5 Exhaust section, 6 Ultraviolet irradiation section, 61 Discharge lamp, 61a Discharge tube, 62 Lamp housing, 62a1 Hole, 65 Shutter, 65a Shielding section, 65b Moving section, 100 Target object

Claims

1. A discharge lamp having a tubular discharge tube extending in one direction; A lamp housing having a space inside in which the discharge lamp is installed, with one end being open, and having a plurality of holes arranged in the direction in which the discharge lamp extends on the surface intersecting the open end; The lamp housing is connected to a surface facing the open end and has an exhaust section capable of exhausting the inside of the lamp housing; In the row of holes, a shutter that can open and close the hole located at the end of the row; A movable part that changes the position of the discharge lamp in at least one of the directions in which the discharge lamp extends and the direction perpendicular to the direction in which the discharge lamp extends; It is equipped with, If the position of the discharge lamp changes due to the moving part, The shutter is an irradiation device that changes the position in which it closes the hole according to the changed position of the discharge lamp.

2. The aforementioned shutter is, When the discharge lamp turns off, the holes located at the end of the row are closed. The irradiation device according to claim 1, wherein when the discharge lamp is lit, the holes located at the end of the row are opened.

3. The aforementioned discharge lamp repeatedly switches on and off. The irradiation device according to claim 2, wherein when the discharge lamp is turned off, the shutter closes the hole located at the end of the row, so that the temperature difference between the central region of the discharge tube and the temperature near the end of the discharge tube is 50°C or less.

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