JP2013012379A - Light irradiation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light irradiation device composed of a plurality of rod-like high-pressure discharge lamps arranged in a row along one direction in which direction the center axes of each lamp extend, which can obtain an even illuminance distribution similar to the one at lamp lighted initial time stably over a long period of time.SOLUTION: The light irradiation device is of such a type that a plurality of rod-like high-pressure discharge lamps having a pair of electrodes disposed oppositely to each other inside the respective bulbs are arranged in a row along one direction in which direction the center axes of each lamp extend. Two adjacent high-pressure discharge lamps are provided with light shading bodies at the respective ends thereof, and are disposed at positions adjusted in the one direction so that a high-pressure discharge lamp on one side of the two high-pressure discharge lamps will get an even illuminance distribution relative to a high-pressure discharge lamp on the other side.

Description

  The present invention relates to a light irradiation apparatus.

Conventionally, as an ultraviolet irradiation light source of a photochemical reaction apparatus used for drying of ink or paint and resin curing treatment, or an ultraviolet irradiation light source of an exposure apparatus for exposing a liquid crystal substrate for a semiconductor substrate or a liquid crystal display, for example, 200 to A long long arc type high-pressure discharge lamp having a peak in one of the wavelength regions of 400 nm is used. In this type of high-pressure discharge lamp, it has been studied that the lamp is cooled and used in order to prevent damage to the lamp itself and to avoid thermal influence on the object to be processed.
For example, as a long arc type high-pressure discharge lamp having a structure capable of effectively performing this cooling, an outer tube is provided in a contact state or a close contact state on the outer periphery of the discharge tube, and a discharge is obtained by cooling the periphery of the outer tube. The thing of the structure which cools a pipe | tube indirectly is known (for example, refer patent document 1).

FIG. 13 is an explanatory cross-sectional view illustrating an outline of a configuration of an example of a conventional light irradiation apparatus.
This light irradiating device includes a cylindrical outer tube 77 made of, for example, quartz glass, and at least a part of the outer peripheral surface of the outer tube 77 in contact with or in close contact with the inner peripheral surface of the outer tube 77. A long arc type high-pressure discharge lamp 70 having a double tube structure, which is composed of a rod-shaped discharge tube 71 as a whole, is provided as a light source.
In the discharge tube 71, a pair of rod-shaped electrodes 73 each made of, for example, tungsten are disposed opposite to each other inside a straight tubular inner tube 72 made of, for example, quartz glass, sealed at both ends, and mercury and a rare gas are appropriately supplied. Each electrode 73 is airtightly embedded in a rod-shaped sealing portion 72A formed in the inner tube 72 through a metal foil 74 made of, for example, molybdenum, from the outer end of the sealing portion 72A. It is electrically connected to an external lead 75 that protrudes outward in the axial direction. The inner tube 72 and the outer tube 77 are fixed by an adhesive via a base 78 at both ends.
This light irradiation device is provided so as to extend along the tube axis of the high-pressure discharge lamp 70 with the high-pressure discharge lamp 70 inserted therethrough. The cylindrical cooling pipe 80 that forms the cooling water flow path R that flows through, and the high-pressure discharge lamp 70 and the cooling pipe 80 are disposed at both ends of the cooling space between the high-pressure discharge lamp 70 and the cooling pipe 80. A cooling mechanism including a tubular cooling water supply channel forming member 85 and a cooling water discharge channel forming member 86 communicating with the water channel R is provided. The high-pressure discharge lamp 70 and the cooling pipe 80 are axially oriented, for example, with the tube axis extending in the horizontal direction and with both ends connected to the cooling water supply flow path forming member 85 and the cooling water discharge flow path forming member 86. The outer peripheral surface of the cooling pipe 80 is held and fixed by, for example, an O-ring (not shown) by the inner side fastening part 88 and, for example, the O-ring (not shown) by the mouth part 89 on the axially outer side. The outer peripheral surface of the high-pressure discharge lamp 70 is held and fixed via
A reflecting mirror 90 is provided at a position on the back side with respect to the light irradiation direction of the high-pressure discharge lamp 70, and light from the high-pressure discharge lamp 70 passes through the mask M supported by the lower mask stage 95. The irradiated object W on the work stage 96 is irradiated.

  In recent years, for example, with an increase in size of a liquid crystal display device, a liquid crystal substrate having a large width is required. However, it is difficult to cover a large irradiation area with a single bar-shaped high-pressure discharge lamp. In practice, a plurality of rod-shaped high-pressure discharge lamps are arranged in the width direction of the workpiece (the length direction of the rod-shaped discharge lamp) at the level position above the level of the workpiece conveyance path, and adjacent high-pressure discharge lamps. In order to prevent the end portions of the workpieces from interfering with each other, they are arranged in a state of being displaced with respect to each other in the transport direction (for example, in a zigzag shape).

JP 2008-146962 A

  Thus, in a configuration in which a plurality of long arc type high pressure discharge lamps are arranged side by side in the length direction, the illuminance is not good in the boundary region (light emitting end region) between two adjacent high pressure discharge lamps. Even when the illuminance in the boundary region is initially uniform, the illuminance in the boundary region decreases as the lighting time elapses, and the life of the high-pressure discharge lamp itself is reduced. There is a problem that a uniform illuminance distribution cannot be maintained in a short time.

The inventors presume that the reason why the illuminance in the boundary region decreases is that a blackening phenomenon occurs in a portion surrounding the vicinity of the electrode of the high pressure discharge lamp in the bulb, and from the end region of the high pressure discharge lamp. By not using the light emission, it is considered that a uniform illuminance distribution can be stably obtained until the lifetime of the high-pressure discharge lamp itself, and the present invention has been completed.
It is an object of the present invention to provide a plurality of rod-shaped high-pressure discharge lamps arranged in the lengthwise direction so that the central axes of the lamps extend in the same direction, and the same uniformity as in the initial stage of lamp operation. An object of the present invention is to provide a light irradiating device that can obtain a stable illuminance distribution for a long time.

In the light irradiation device of the present invention, a plurality of rod-shaped high-pressure discharge lamps each having a pair of electrodes facing each other inside a bulb are arranged side by side in a state where each lamp central axis extends in one direction. In the irradiated light device,
A light shield is provided at each end of two adjacent high-pressure discharge lamps, and one high-pressure discharge lamp of the two high-pressure discharge lamps has a uniform illuminance distribution with respect to the other high-pressure discharge lamp. It is arranged at the position adjusted in the one direction so as to be obtained.

  In the light irradiation apparatus of the present invention, the lamp central axes of two adjacent high-pressure discharge lamps have the same horizontal plane in a direction perpendicular to the one direction with one lamp central axis with respect to the other lamp central axis. It can be set as the structure arrange | positioned displaced within.

  In the light irradiation apparatus of the present invention, each of the high-pressure discharge lamps has a water cooling pipe that forms a cooling water flow path for circulating cooling water along the outer peripheral surface of the bulb, and the light blocking body is the water cooling device. Each of the high pressure discharge lamps has a configuration provided on the inner peripheral surface or outer peripheral surface of the tube, or each of the high-pressure discharge lamps has an outer tube in which at least a part of the outer peripheral surface is in contact or close contact. And a water cooling pipe that forms a cooling water flow path for circulating cooling water along the outer peripheral surface of the outer pipe, and the light-shielding body is an inner peripheral face or an outer peripheral face of the water cooling pipe, or an outer periphery of the outer pipe. It can be set as the structure provided in the surface.

  Furthermore, in the light irradiation apparatus of this invention, the said light shielding body can be set as the structure which consists of metals.

  According to the light irradiation apparatus of the present invention, in a configuration in which a plurality of rod-shaped high-pressure discharge lamps are arranged side by side in one direction with each lamp central axis extending in one direction, A light shield is provided at each end of the high-pressure discharge lamp so that one of the two high-pressure discharge lamps can obtain a uniform illuminance distribution with respect to the other high-pressure discharge lamp. Since it is configured to be arranged at the position adjusted in the direction, it does not use light emission from the end area where the illuminance decreases with the passage of lamp lighting time, so it is the same as the initial lamp lighting A uniform illuminance distribution can be obtained stably for a long time.

  Each of the high-pressure discharge lamps has a water cooling tube that forms a cooling water flow path for circulating cooling water along the outer peripheral surface of the bulb, and a light shielding body is provided on the inner peripheral surface of the water cooling tube. In some cases, the light shielding body can be directly cooled by cooling water when the lamp is lit, so that the light shielding body itself can be prevented from being deteriorated or damaged by being heated by light irradiation from the high-pressure discharge lamp. Therefore, the intended function of the light shield can be maintained for a long time, and the above-described effect can be obtained with certainty.

It is explanatory drawing which shows the outline of a structure in an example of the light irradiation apparatus of this invention. It is sectional drawing along the lamp | ramp central axis which shows the outline of a structure in an example of the high pressure discharge lamp used in the light irradiation apparatus of this invention. It is an expanded sectional view which expands and shows a part of high-pressure discharge lamp shown in FIG. (A) Explanatory drawing which shows the arrangement | sequence state of the high pressure discharge lamp in the light irradiation unit produced in Experimental example 1, (B) It is explanatory drawing which shows the positional relationship of each edge part of an adjacent high pressure discharge lamp. (A) Explanatory drawing which shows the arrangement | sequence state of the high pressure discharge lamp in the comparative light irradiation unit produced in Experimental example 1, (B) It is explanatory drawing which shows the positional relationship of each edge part of an adjacent high pressure discharge lamp. It is explanatory drawing which shows the outline of a structure of the illumination intensity measurement system for measuring the integrated illumination intensity by each light irradiation unit produced in Experimental example 1. FIG. It is a graph which shows the illumination intensity distribution in one direction by the light irradiation unit which concerns on this invention. It is a graph which shows the illumination intensity distribution of the boundary part of the adjacent high pressure discharge lamp in FIG. It is a graph which shows the illumination intensity distribution in one direction by the light irradiation unit for a comparison. It is a graph which shows the illumination intensity distribution of the boundary part of the adjacent high pressure discharge lamp in FIG. It is an expanded sectional view in alignment with the lamp | ramp center axis | shaft which shows the outline of the structure in the other example of the high pressure discharge lamp used in the light irradiation apparatus of this invention partially expanding. It is an expanded sectional view in alignment with the lamp | ramp central axis which shows the outline of the structure in the further another example of the high pressure discharge lamp used in the light irradiation apparatus of this invention partially expanding. It is sectional drawing for description which shows the outline of a structure in an example of the conventional light irradiation apparatus.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is an explanatory diagram showing an outline of a configuration in an example of a light irradiation apparatus of the present invention.
This light irradiation device has an upper space portion and a lower space portion that are divided into upper and lower portions by a flat partition plate 55 inside, and a plurality of rod-shaped high-pressure discharge lamps 10 are disposed in the lower space portion. A casing 50 is provided as a lamp arrangement space portion 51 and an upper space portion serving as an electric component arrangement space portion 52 in which a power source (not shown) for supplying power to each high-pressure discharge lamp 10 is arranged. The casing 50 is, for example, in a direction (left and right direction in FIG. 1, the width direction of the irradiated object W) orthogonal to the conveying direction of the irradiated object (work) W conveyed by an appropriate conveying means (not shown). The entire length is substantially box-shaped.

  As shown in FIGS. 2 and 3, each high-pressure discharge lamp 10 extends along the tube axis of the discharge tube 11 in a state where the discharge tube 11 is substantially rod-shaped as a whole and the discharge tube 11 is inserted into the discharge tube 11. A so-called indirect water-cooling type, for example, comprising a cylindrical water-cooled tube 20 that forms a cooling water flow path R through which cooling water is circulated between the outer peripheral surface of the discharge tube 11 and, for example, Light including ultraviolet rays having a wavelength of 200 to 450 nm is emitted.

In the discharge tube 11, a pair of rod-like electrodes 13 each made of tungsten, for example, are arranged oppositely in a bulb 12 made of, for example, quartz glass whose both ends are sealed, and mercury and argon gas of, for example, 1 mg / cm ³ or more. The inner tube 16 is filled with an appropriate amount of a rare gas, and the inner peripheral surface is made of, for example, quartz glass disposed in contact with or in close contact with the outer peripheral surface of the central portion of the bulb 12 in the inner tube 16. The inner tube 16 and the outer tube 18 are fixed by an adhesive via lamp bases 19 provided at both ends of the inner tube 16.
Each electrode 13 in the inner tube 16 protrudes outward in the axial direction from the outer end of the sealing portion 12A through a metal foil 14 made of molybdenum, for example, which is airtightly embedded in the rod-shaped sealing portion 12A in the valve 12. It is electrically connected to the extending external lead 15. The sealing portion 12A in the valve 12 is formed by, for example, a shrink seal method in which both ends of a straight pipe body that is a constituent material of the valve are melted to decompress the inside.

  The water-cooled tube 20 is made of a material that transmits ultraviolet rays radiated from the high-pressure discharge lamp 10, for example, quartz glass.

  In the high-pressure discharge lamp 10, for example, water-cooled bases 25 having the same configuration are provided at both ends in the length direction. Each of the water-cooled bases 25 has a substantially cylindrical shape in which a central through hole 26 extending in the length direction of the high-pressure discharge lamp 10 is formed, and the inner peripheral surface of the central through hole 26 has a large inner diameter. A plurality of step portions forming a plurality of substantially cylindrical space portions having different sizes are formed.

In the discharge tube 11, the end portion of the outer tube 18 is inserted into a cylindrical space having the smallest inner diameter and is held by the water-cooled base 25, and is provided on the outer peripheral surface of the outer tube 18, for example, O−. In a state where the seal member made of the ring 30A is positioned on the outer flat surface constituting the minimum diameter step portion 27A, the screw 31 is attached to the end surface on the outer side in the length direction of the high-pressure discharge lamp 10 in the water cooling base 25. The O-ring 30A is pressed and elastically deformed by an annular plate 32 to be attached via a cylindrical washer 33 having an inner diameter larger than the outer diameter of the outer tube 18, and thereby the water-cooled base 25 is deformed. It is fixed in a watertight state.
Further, the end of the water-cooled tube 20 is inserted into a cylindrical space having the second largest inner diameter, and the end surface of the water-cooled tube 20 is in contact with the flat surface constituting the maximum diameter step portion 27B. In this state, a seal member made of, for example, an O-ring 30B provided on the outer peripheral surface of the water-cooled tube 20 is held on the flat surface on the inner side constituting the maximum diameter step portion 27B. In the positioned state, a cylindrical washer having an inner diameter larger than the outer diameter of the water-cooled tube 20 by an annular plate 32 attached to the end surface of the water-cooled base 25 in the longitudinal direction of the high-pressure discharge lamp 10 by a screw 31. The O-ring 30 </ b> B is pressed and elastically deformed through 33, thereby being fixed to the water-cooled base 25 in a watertight state.

  Further, plugs 35A and 35B for introducing or discharging cooling water, for example, are formed on the outer peripheral surface of each water-cooled base 25 so as to extend radially outward. The cooling water introduced from 35A is circulated in the cooling water flow path R along the outer peripheral surface of the outer pipe 18, and the plug 35B in the other water cooling base 25 is discharged, whereby the high pressure discharge lamp 10 is discharged when the lamp is turned on. A water cooling mechanism for cooling is configured.

Thus, each of the high-pressure discharge lamps 10 is provided with a light shielding body 40 at each of both end portions in the length direction, for example.
In the light irradiation apparatus according to this embodiment, the sleeve-shaped light blocking body 40 covers a portion where the blackening phenomenon may occur with the passage of the lamp lighting time in the bulb 12, for example, the periphery of the inner wall portion in the vicinity of the electrode periphery. The water cooling tube 20 is provided so as to be inserted into the inner peripheral surface. Specifically, the light shielding body 40 has a flange portion 41 formed at one end thereof sandwiched between a flat surface constituting the maximum diameter step portion 27 </ b> B in the water cooling base 25 and an edge surface of the water cooling tube 20. Holding fixed. As described above, since the light shielding body 40 is positioned in the cooling water flow passage R, the light shielding body 40 can be directly cooled by the cooling water when the lamp is lit. Or it can prevent that it breaks.

As a material constituting the light shield 40, for example, a metal material such as aluminum or stainless steel or a ceramic material can be used.
The thickness of the light shielding body 40 is, for example, in the range of 1 mm or less and 0.1 to 1.0 mm.

  The light blocking body 40 is provided in a state in which the distance between the position of the inner edge and the tip position of the electrode 13 in the length direction of the high-pressure discharge lamp 10 is, for example, 20 mm or less, for example, 5 to 20 mm. It is preferable. Thereby, it is possible to reliably shield light emitted from a portion where a blackening phenomenon may occur as the lamp lighting time elapses.

  In this light irradiating apparatus, each high-pressure discharge lamp 10 is provided with a high-pressure shield-like reflecting mirror 60 having a reflecting surface having an elliptical cross section, for example, on the back side with respect to the light irradiation direction (downward in FIG. 1). It is arranged so as to extend along the length direction of the discharge lamp 10. The reflecting mirror 60 may be provided with a cold mirror coating that reflects only ultraviolet light having a target wavelength and transmits unnecessary visible light and infrared light.

Thus, in this light irradiation apparatus, a plurality of the high-pressure discharge lamps 10 having the same configuration, for example, are transported in the lamp arrangement space 51 in the casing 50 with each lamp central axis C in one direction (conveyed). It is arranged side by side in the state extending in the width direction of the workpiece W, and one of the two adjacent high-pressure discharge lamps is adjusted in one direction so as to obtain a uniform illuminance distribution with respect to the other. Arranged in position.
Specifically, with reference to FIG. 4A, one of two high-pressure discharge lamps adjacent to each other when viewed from the conveyance direction of the irradiation object W (direction perpendicular to the paper surface in FIG. 1). The lamp central axis C in the high-pressure discharge lamp 10A (10B) is displaced in a direction perpendicular to the one direction (conveyance direction of the irradiated object W) with respect to the lamp central axis C in the other high-pressure discharge lamp 10B (10C). Further, a region (light-shielding region) provided with the light-shielding body 40 in one high-pressure discharge lamp 10A (10B) and a region (light-shielding region) provided with the light-shielding body 40 in the other high-pressure discharge lamp 10B (10C). Are arranged in a zigzag state, for example, in such a way that a uniform illuminance distribution can be obtained in one direction (the width direction of the irradiated object W). There is a. “Uniform illuminance distribution” means that the average value of integrated illuminance in the conveyance direction of an object to be irradiated has uniformity so that it is within ± 10%.

  Thus, according to the light irradiation device having the above-described configuration, the plurality of high-pressure discharge lamps 10 each provided with the light shielding body 40 at each of both end portions thereof are adjacent to each other so as to obtain a uniform illuminance distribution. The lamp central axis in one high-pressure discharge lamp 10A (10B) of the lamp is perpendicular to the one direction (transport direction of the irradiated object W) with respect to the lamp central axis C in the other high-pressure discharge lamp 10B (10C). In addition, the region of the one high-pressure discharge lamp 10A (10B) provided with the light-shielding body 40 (light-shielding region) and the region of the other high-pressure discharge lamp 10B (10C) provided with the light-shielding body 40 ( An edge where the illuminance decreases as the lamp lighting time elapses due to the arrangement in which a part of the light-shielding region overlaps in the conveyance direction of the irradiated object W. Because light emission from the area is not used, the same uniform illuminance distribution as the initial lamp lighting is stable for a long time regardless of the occurrence of the blackening phenomenon of the bulb with the passage of lamp lighting time. Can be obtained.

  Each of the high-pressure discharge lamps 10 has a water cooling tube 20 that forms a cooling water flow path R through which cooling water flows along the outer peripheral surface of the bulb 12, and a light blocking body 40 is provided on the inner peripheral surface of the water cooling tube 20. With this configuration, the light shield 40 can be directly cooled by the cooling water when the lamp is lit. Therefore, the light shield 40 itself is deteriorated or damaged by being heated by light irradiation from the high-pressure discharge lamp 10. Therefore, the expected function of the light shield 40 can be maintained for a long time, and the above-described effect can be obtained with certainty.

Hereinafter, experimental examples performed for confirming the effects of the present invention will be described.
As shown in FIG. 4, three indirect water-cooled high-pressure discharge lamps 10A, 10B, and 10C having the configurations shown in FIGS. 2 and 3 extend in one direction in the same horizontal plane with the lamp center axis C being the same. In the present invention, the present invention is arranged in a staggered manner so as to obtain a uniform illuminance distribution at a position 100 mm below the lamp central axis C (a position corresponding to the light irradiation surface of the irradiated object in the actual light irradiation apparatus). The light irradiation unit which concerns is produced. Further, as shown in FIG. 5, the high-pressure discharge lamp having the configuration shown in FIGS. 2 and 3 has the same configuration as that shown in FIGS. 2 and 3 except that it does not have a light shield. The high-pressure discharge lamps 101, 102, 103 are placed at a position of 100 mm below the lamp central axis C (in the actual light irradiation device, with each lamp central axis C extending in one direction within the same horizontal plane. A comparative light irradiation unit arranged in a zigzag pattern was produced so that a uniform illuminance distribution was obtained at a position corresponding to the light irradiation surface of the irradiated object. The specification of each light irradiation unit is as follows.
In each light irradiation unit, as shown in FIG. 6, the arrangement position of the high-pressure discharge lamp is such that an illuminance meter 66 is placed on a transporter 65 arranged at a position of 100 mm below the lamp central axis C of the high-pressure discharge lamp 10. The illuminance measurement for measuring the integrated illuminance by arranging and moving the illuminance meter 66 in a direction orthogonal to one direction (vertical direction in FIGS. 4 and 5) is performed at a plurality of measurement positions at predetermined intervals in one direction. The integrated illuminance values at all measurement positions were set within a range of ± 10% with respect to the average value.

[High pressure discharge lamp (10)]
Bulb (12): made of quartz glass, the inner diameter of the central part is φ6 mm, the wall thickness is 2 mm, the total length is 360 mm,
Outer tube (18): made of quartz glass, inner diameter is φ10 mm, outer diameter is φ13 mm, total length is 380 mm,
Water-cooled tube (20): made of quartz glass, inner diameter is φ16mm, wall thickness is 2mm, total length is 350mm,
Electrode (13): made of tungsten, distance between electrodes 250 mm, length of the electrode part located in the discharge space 3 mm,
Inclusion material: mercury; 5.0 mg / cm ³ , argon gas; 10 kPa,
Light-shielding body (40): made of aluminum, having an outer diameter of φ16 mm, a thickness of 0.5 mm, and a separation distance between the position of the inner edge surface in the length direction of the high-pressure discharge lamp and the electrode tip surface (FIG. 4B) L1) is 20 mm (effective light emission length of the high-pressure discharge lamp is 210 mm),
Rated voltage: 1000V, rated current: 6A,

[Light Irradiation Unit According to the Present Invention]
Of two adjacent high-pressure discharge lamps, the dimension in one direction (L2 in FIG. 4B) where the light-shielding region of one high-pressure discharge lamp 10A and the light-shielding region of the other high-pressure discharge lamp 10B overlap is 10 mm. In addition, the separation distance (L3 in FIG. 4B) in one direction between the electrode tip surface of one high-pressure discharge lamp 10A and the electrode tip surface of the other high-pressure discharge lamp 10B is 30 mm. Further, the distance (L4 in FIG. 4B) between the lamp central axis C in one high-pressure discharge lamp 10A and the lamp central axis C in the other high-pressure discharge lamp 10B is 150 mm. The positional relationship between the high pressure discharge lamp 10B and the high pressure discharge lamp 10C is the same as the positional relationship between the high pressure discharge lamp 10A and the high pressure discharge lamp 10B. Each high-pressure discharge lamp is provided at a position on the back side with respect to the light irradiation direction so as to extend along the central axis of the lamp of each high-pressure discharge lamp. It was.

[Light irradiation unit for comparison]
The distance between two adjacent high pressure discharge lamps in one direction between the electrode front end surface of one high pressure discharge lamp 101 and the electrode front end surface of the other high pressure discharge lamp 102 (L5 in FIG. 5B) is 10 mm. The distance (L6 in FIG. 5B) between the lamp central axis C in one high-pressure discharge lamp 101 and the lamp central axis C in the other high-pressure discharge lamp 102 is 150 mm. The positional relationship between the high pressure discharge lamp 102 and the high pressure discharge lamp 103 is the same as the positional relationship between the high pressure discharge lamp 101 and the high pressure discharge lamp 102.
Each high-pressure discharge lamp is provided at a position on the back side with respect to the light irradiation direction so as to extend along the central axis of the lamp of each high-pressure discharge lamp. It was.

  For each of the light irradiation unit according to the present invention and the light irradiation unit for comparison, the integrated illuminance of light with a wavelength of 365 nm is measured by an illuminometer by the illuminance measurement system shown in FIG. 6, and the lamp central axis of each high-pressure discharge lamp The degree of change in the uniformity of the illuminance distribution in one direction along the direction of the illuminance (conveyance direction of the illuminometer by the conveyor) with the passage of the lamp lighting time was examined. Here, the lighting conditions of each high-pressure discharge lamp were such that the lamp input per 1 cm of the arc length was 240 W / cm, and the flow rate of the cooling water flowing through the cooling water flow path was 10 liters / min.

FIG. 7 is a graph showing the integrated illuminance distribution in one direction by the light irradiation unit according to the present invention, and FIG. 8 is a graph showing the integrated illuminance distribution at the boundary portion of adjacent high-pressure discharge lamps in FIG. 7 and 8, the curve (A) shows the integrated illuminance distribution at the initial stage of lamp lighting, and the curve (B) shows the integrated illuminance distribution when the lamp lighting time has passed 2000 hours.
As is clear from this result, according to the light irradiation unit of the present invention, it was confirmed that the uniformity of the integrated illuminance distribution at the beginning of lighting was maintained for a long time. The reason for this is that a plurality of high-pressure discharge lamps having light-shielding bodies provided in advance at their ends are arranged so that a uniform illuminance distribution can be obtained without using light emission from each end region of adjacent high-pressure discharge lamps. With this configuration, it is considered that the uniformity of the illuminance distribution at the initial stage of lamp lighting can be maintained regardless of the occurrence of the blackening phenomenon of the bulb as the lamp lighting time elapses. In addition, the light shield is heated by receiving the ultraviolet rays from the high-pressure discharge lamp, but is directly cooled by the cooling water, so that the light shield itself is prevented from being deteriorated or damaged. The point that the function of the period is maintained for a long time is also considered as a reason that the uniformity of the illuminance distribution is maintained.

  On the other hand, as shown in FIGS. 9 and 10, in the comparative light irradiation unit, the difference between the maximum value and the minimum value of the integrated illuminance value in the integrated illuminance distribution in one direction is about 10% of the average value. When the lamp lighting time has passed 1000 hours (curve (FIG. 9 and FIG. 10) (curve (A) in FIG. 9 and FIG. 10) with respect to the lamp lighting initial stage (curve (A) in FIG. 9 and FIG. 10) having a uniformity within the range. In B)), it was confirmed that the difference between the maximum value and the minimum value of the integrated illuminance value was about 20% of the average value, and the uniformity in the integrated illuminance distribution was reduced. The reason for this is that, as is apparent from FIGS. 9 and 10, the accumulated illuminance in each end region (boundary portion) of the adjacent high-pressure discharge lamp has decreased, and the time when the lamp lighting time has passed 1000 hours has elapsed. When the end region of the high-pressure discharge lamp was visually observed, it was confirmed that blackening occurred in the inner wall portion of the bulb located around the tip of the electrode.

As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment, A various change can be added.
For example, in the high-pressure discharge lamp according to the above-described embodiment, the light-shielding body is provided at each of both end portions in the length direction, but on the outermost side in one direction in which a plurality of high-pressure discharge lamps are arranged. The positioned high-pressure discharge lamp may have a configuration in which a light blocking body is provided only at one end adjacent to another high-pressure discharge lamp. Further, the light shielding body is not limited to a sleeve shape, and may be constituted by, for example, a vapor deposition film.

Further, the position at which the light blocking body is disposed is not limited to the inner peripheral surface of the water-cooled tube, and may be any position that can block light emitted from the end region of the high-pressure discharge lamp.
For example, as shown in FIG. 11, the light shielding body 40 may be provided on the outer peripheral surface of the outer tube 18 constituting the discharge tube 11. In the high-pressure discharge lamp 10, the sleeve-shaped light shield 40 constitutes the minimum diameter step portion 27 </ b> A in the water-cooled base 25 with the end portion of the outer tube 18 constituting the discharge tube 11 inserted therein. It is inserted and held in the cylindrical space. Moreover, as shown in FIG. 12, the light shielding body 40 may be configured to be provided on the outer peripheral surface of the water-cooled tube 20. In the high-pressure discharge lamp 10, the sleeve-shaped light-shielding body 40 has an end portion of the water-cooled tube 20 inserted therein, and the flange portion 41 formed at one end thereof is the inner side of the water-cooled base 25. The screw 31 is fixed in contact with the end face of the screw.

  Furthermore, the high pressure discharge lamp is not limited to a double tube structure.

10, 10A, 10B, 10C High pressure discharge lamp 101, 102, 103 High pressure discharge lamp 11 Discharge tube 12 Valve 12A Sealing portion 13 Electrode 14 Metal foil 15 External lead 16 Inner tube 18 Outer tube C Lamp central axis 19 Lamp base 20 Water cooling Pipe R Cooling water flow path 25 Water cooling base 26 Central through hole 27A Minimum diameter step portion 27B Maximum diameter step portion 30A, 30B O-ring 31 Screw 32 Plate 33 Washer 35A, 35B Plug 40 Light shield 41 Flange portion 50 Casing 51 Lamp arrangement space Part 52 Electrical component arrangement space part 55 Partition plate 60 Reflective mirror 65 Transporter 66 Illuminance meter 70 High pressure discharge lamp 71 Discharge tube 72 Inner tube 72A Sealing part 73 Electrode 74 Metal foil 75 External lead 77 Outer tube 78 Base 80 Cooling tube 85 Cooling water supply flow path forming member 86 Cooling Discharge flow path forming member 88, 89 neck clamping portion 90 reflecting mirror 95 mask stage 96 workpiece W irradiated object (workpiece)
M mask

Claims (5)

In a light irradiation apparatus in which a plurality of rod-shaped high-pressure discharge lamps each having a pair of electrodes opposed to each other inside each bulb are arranged side by side in a state in which each lamp central axis extends in one direction,
A light shield is provided at each end of two adjacent high-pressure discharge lamps, and one high-pressure discharge lamp of the two high-pressure discharge lamps has a uniform illuminance distribution with respect to the other high-pressure discharge lamp. The light irradiation apparatus is arranged at a position adjusted in the one direction so as to be obtained.   The lamp center axes of two adjacent high-pressure discharge lamps are arranged such that one lamp center axis is displaced in the same horizontal plane in a direction perpendicular to the one direction with respect to the other lamp center axis. The light irradiation apparatus according to claim 1. Each of the high-pressure discharge lamps has a water cooling tube that forms a cooling water flow path for circulating cooling water along the outer peripheral surface of the bulb,
The light irradiation apparatus according to claim 1, wherein the light shielding body is provided on an inner peripheral surface or an outer peripheral surface of the water-cooled tube. Each of the high-pressure discharge lamps has an outer tube in which at least a part of the outer peripheral surface of the bulb is disposed in contact or in close contact with the bulb, and the cooling water is circulated along the outer peripheral surface of the outer tube. Having a water cooling tube forming a cooling water flow path;
The light irradiation apparatus according to claim 1, wherein the light shielding body is provided on an inner peripheral surface or an outer peripheral surface of the water-cooled tube or an outer peripheral surface of the outer tube.   The light irradiation apparatus according to claim 1, wherein the light blocking body is made of a metal.

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