JP2009064987A - Light source unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source unit further enhancing the degree of thermal coupling between a header and a cooling fluid than in a conventional configuration. <P>SOLUTION: The light source unit 1 is provided with: light-emitting modules M each having a substrate 2 made of an excellent heat-transfer material and a plurality of light-emitting diode chips 3 provided on one surface of the substrate 2; and a header 4 made of an excellent heat-transfer material and allowing the plurality of light-emitting modules M to couple thereto in a way of abutting on the other surface of the substrate 2. The header 4 has flow paths 15 for flowing cooling water for cooling the light-emitting modules M, the plurality of flow paths 15 are formed for one header 4, and the flow paths 15 are each equipped with a flow-in port for allowing the cooling water to flow in from the outside of the header 4, and a flow-out port for allowing the cooling water to flow out to the outside of the header 4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a light emitting module having a substrate made of a highly heat conductive material, a plurality of light emitting diode chips provided on one surface of the substrate, and cooling for cooling the light emitting module to which the light emitting module can be coupled. The present invention relates to a light source unit including a header having a flow path for flowing a working fluid.

  In recent years, various light source units using light emitting diode (hereinafter referred to as “LED”) chips have been proposed for the purpose of reducing power consumption and extending the service life, instead of conventionally used discharge lamps and the like. Such a light source unit is used, for example, in a printing system that cures ultraviolet-curable ink that is cured by receiving ultraviolet rays by using an LED chip that emits ultraviolet rays.

  This type of light source unit includes a light emitting module in which a plurality of LED chips are mounted on one surface of a single substrate in order to obtain the same amount of light as a conventional light source unit such as a discharge lamp. It has been known. Further, in this type of light source unit, there are cases where a plurality of light emitting modules are provided and the LED chips of the plurality of light emitting modules emit light at the same time in order to expand the light irradiation range and increase the amount of light.

  However, when adopting a configuration in which a plurality of LED chips are mounted on a single substrate, there is a problem with the treatment of heat generated when the LED chips emit light. That is, when an LED chip is energized to emit light, the LED chip itself generates heat as is well known. However, in a light emitting module in which a plurality of LED chips are mounted on a single substrate as described above, the amount of heat generated is This is several times as large as one LED chip. Here, since the luminous efficiency of the LED chip has a negative temperature coefficient, the luminous efficiency of the LED chip significantly decreases as the temperature rises. Therefore, in the light source unit, it is necessary to apply a configuration in which heat generated in the light emitting module is forcibly radiated (see, for example, Patent Document 1).

As a configuration for forcibly radiating the heat of the light emitting module, for example, as shown in FIG. 7, one having a header 4 to which the light emitting module M ′ can be coupled is known (see, for example, Patent Document 2). In the invention described in Patent Document 2, a flow path 15 for flowing cooling water (cooling fluid) for cooling the light emitting module (here, laser diode array) M ′ is formed in the header 4, and the light emitting module M ′ A water cooling structure for cooling the light emitting module M ′ by radiating the generated heat with cooling water is adopted. In Patent Document 2, as shown in FIG. 7, the flow path 15 through which the cooling water flows is that the cooling water taken into the header 4 from the water supply port 23 provided in the header 4 is discharged from the drain port 24 provided in the header 4 to the outside of the header 4. Only one is formed for each header 4 so as to be drained. In the light source unit 1, the flow rate of the cooling water can be increased by increasing the cross-sectional area of the flow path 15, and the cooling efficiency of the light emitting module M ′ by the cooling water can be improved.
JP 2004-362900 A JP-A-8-139479 (see paragraph 0002, FIG. 3)

  By the way, in the light source unit 1 having the above configuration, the header 4 is in contact with the cooling water only on the inner peripheral surface of the flow path 15, and heat exchange between the header 4 and the cooling water is performed on the inner peripheral surface of the flow path 15. Therefore, as the area of the inner peripheral surface of the flow path 15 is larger, the degree of thermal coupling between the header 4 and the cooling water is higher, and the cooling efficiency of the light emitting module M ′ is higher. However, in the light source unit 1, only one flow path 15 is formed for one header 4, so even if the cross-sectional area of the flow path 15 is increased, the area of the inner peripheral surface of the flow path 15. Is limited by the size of the header 4, and the degree of thermal coupling between the header 4 and the cooling water is limited.

  This invention is made | formed in view of the said reason, Comprising: It aims at providing the light source unit which can improve the thermal coupling degree of a header and cooling water from a conventional structure.

  The invention of claim 1 is a light emitting module having a substrate made of a highly heat conductive material, and a plurality of light emitting diode chips provided on a light emitting region on one surface of the substrate, and a plurality of light emitting devices made of a highly heat conductive material. The module includes a header that can be coupled so as to abut the other surface of the substrate, and the header has a flow path for flowing a cooling fluid for cooling the light emitting module, and the flow path is connected to one header. A plurality of flow paths are formed, and each flow path includes both an inflow port through which the cooling fluid flows from the outside of the header and an outflow port from which the cooling fluid flows out of the header. Features.

  According to this configuration, since a plurality of flow paths for flowing the cooling fluid are formed for one header, the flow path is compared with the conventional configuration in which only one flow path is formed for one header. The area of the inner peripheral surface of the header can be increased, and therefore, the contact area of the header with the cooling fluid can be increased as compared with the conventional configuration. This improves the thermal coupling between the header and the cooling fluid, improves the efficiency of heat exchange between the header and the cooling fluid, and transfers the heat generated in the light emitting diode chip to the cooling fluid. This is advantageous in that the cooling efficiency of the light emitting module is improved. In addition, each flow path includes both an inflow port through which the cooling fluid flows from the outside of the header and an outflow port through which the cooling fluid flows out of the header, so that the cooling fluid is contained in the header. Therefore, the cooling fluid of a low temperature can be supplied from each inflow port to all the flow paths, and the cooling efficiency of the light emitting module can be improved.

  According to a second aspect of the present invention, in the first aspect of the present invention, the plurality of flow paths includes a first flow path for flowing the cooling fluid along a direction in which the light emitting regions of the plurality of light emitting modules are arranged, and It includes at least one combination with the second flow path for flowing the cooling fluid so as to reduce the temperature difference between the light emitting regions generated between the light emitting modules when the cooling fluid is flowed to the one flow path. .

  According to this configuration, the temperature difference between the light emitting regions generated between the light emitting modules when the cooling fluid is supplied to the first flow path is reduced by flowing the cooling fluid to the second flow path. Variations in luminous efficiency due to the temperature rise of the light emitting diode chip in the light emitting region can be suppressed between the light emitting module disposed on the upstream side of one flow path and the light emitting module disposed on the downstream side of the first flow path. In addition, it is possible to realize a light emitting surface with less luminance unevenness.

  According to a third aspect of the present invention, in the second aspect of the present invention, the plurality of light emitting modules are coupled to the header such that the light emitting areas are aligned, and the second flow path is defined relative to the straight line. The cooling fluid is made to flow in a direction opposite to the first flow path.

  According to this configuration, the first flow path and the second flow path are simple in that the first flow path and the second flow path are arranged symmetrically with respect to the straight line in which the light emitting regions are arranged. In addition, by causing the cooling fluids to flow in opposite directions, the temperature difference between the light emitting regions generated between the light emitting modules can be reduced.

  According to a fourth aspect of the present invention, in the second or third aspect of the present invention, the outflow port of the first flow path and the inflow port of the second flow path are coupled to each other outside the header by a connecting pipe. And a cooling device for forcibly cooling the cooling fluid flowing in the connecting pipe is provided outside the header.

  According to this configuration, since the cooling fluid that has flowed through the first flow path is cooled in the connecting pipe and then flows into the second flow path, the cooling fluid that flows through the first flow path and the cooling that flows through the second flow path By sharing the cooling fluid, the flow rate of the cooling fluid is reduced compared to the case where the cooling fluid is individually flowed through the first flow path and the second flow path, but the first flow path and the second flow path are reduced. A low-temperature cooling fluid can be supplied to both of the flow paths.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the header is made of aluminum nitride, and the corrosion by the cooling fluid is performed over the entire inner peripheral surface of the flow path. It is characterized by having a thin non-reactive layer for preventing the above.

  According to this configuration, since the inner peripheral surface of the flow path has the non-reactive layer that prevents corrosion due to the cooling fluid, the periphery of the flow path in the header is corroded by flowing the cooling fluid through the flow path. Can be avoided.

  In the present invention, since a plurality of flow paths for flowing the cooling fluid are formed for one header, the area of the inner peripheral surface of the flow path can be increased as compared with the conventional configuration. Therefore, the contact area of the header with the cooling fluid can be made larger than in the conventional configuration, and the degree of thermal coupling between the header and the cooling fluid is improved. In addition, each channel has both an inlet and an outlet, so that a low-temperature cooling fluid can be supplied from each inlet to all the channels. The cooling efficiency can be improved.

(Embodiment 1)
As shown in FIG. 1, the light source unit 1 according to the present embodiment includes a substrate 2 and a plurality of light emitting diode (hereinafter referred to as LED) chips 3 provided on one surface (hereinafter referred to as a front surface) of the substrate 2. A module M and a header 4 to which a plurality of light emitting modules M can be coupled are provided.

  The substrate 2 is formed in a rectangular shape (so-called strip shape) whose front surface is long in one direction. As shown in FIG. 2, a plurality of LED chips 3 are arranged in the vertical and horizontal directions of the front surface of the substrate 2 (here, 4). Are arranged in lattice points so that they are lined up one by one. These LED chips 3 are arranged in a light emitting region (not shown) set at the center of the front surface of the substrate 2. The substrate 2 is made of a highly heat conductive material (for example, copper) having excellent heat conductivity. Thus, when the LED chip 3 emits light, the heat generated in the LED chip 3 is transmitted to the substrate 2, further moves in the substrate 2 by heat conduction, and is transmitted to the back side of the substrate 2. Here, the substrate 2 is electrically connected to one electrode (anode) of the LED chip 3 by using a conductive material for the substrate 2 and die-bonding the LED chip 3 to the substrate 2.

  Further, the light emitting module M has a plate-like cover 6 attached to the front surface of the substrate 2. The cover 6 is provided with an exposure hole 7 that is opened in a circular shape at a position corresponding to the light emitting region of the substrate 2 so that the plurality of LED chips 3 are exposed forward. The inner peripheral surface of the exposure hole 7 is inclined so as to increase the inner diameter of the exposure hole 7 as the distance from the substrate 2 increases. A lens 8 whose outer peripheral surface is a convex curved surface (for example, a part of a spherical surface) is attached to the exposure hole 7, and the substrate 2, the cover 6, and the lens 8 surround the space where the LED chip 3 is mounted. Thereby, the space in which the LED chip 3 is mounted is blocked from the influence of the surrounding environment such as humidity. Here, the cover 6 is made of a conductive material (for example, copper), and the other electrode (cathode) of the LED chip 3 is connected to the cover 6 by wire bonding. Thus, the plurality of LED chips 3 in each light emitting module M are connected in parallel so that each of the substrate 2 and the cover 6 serves as an electrode. An insulating sheet 9 made of an insulating material is interposed between the substrate 2 and the cover 6 to insulate the substrate 2 and the cover 6 from each other.

  Here, as shown in FIG. 3, the substrate 2 and the cover 6 are both rectangular when viewed from the front, and are formed to have substantially the same width. Further, the substrate 2 and the cover 6 have different longitudinal dimensions, and the substrate 2 is formed to have a longer longitudinal dimension than the cover 6. Furthermore, the longitudinal center of the substrate 2 and the longitudinal center of the cover 6 are different in position, and the longitudinal center of the cover 6 is located closer to one end in the longitudinal direction than the longitudinal center of the substrate 2. Thus, the cover 6 is attached to the substrate 2. At both ends in the longitudinal direction of the substrate 2, mounting holes 10 used when the substrate 2 is coupled to the header 4 are respectively penetrated. Further, connection screw holes 11 and 12 are formed in each of the substrate 2 and the cover 6. Each connection screw hole 11, 12 is positioned between the longitudinal center of the substrate 2 and each mounting hole 10, and extends from the longitudinal center of the substrate 2 to each connection screw hole 11, 12. The distance is equidistant. The connection screw holes 11 and 12 are used to electrically connect the LED chip 3.

  With the above configuration, the mounting holes 10 and the connecting screw holes 11 and 12 are positioned symmetrically with respect to the center line along the width direction of the substrate 2 when viewed from the front. On the other hand, the cover 6 is disposed so as to cross the center line so as to be asymmetric with respect to the center line along the width direction of the substrate 2, and the distance from the center line to one end of the substrate 2. And the distance to the other end is different. Further, the cover 6 is laminated on the substrate 2 via the insulating sheet 9, and one connection screw hole 11 is formed in the substrate 2, and the other connection screw hole 12 is formed in the cover 6. Therefore, the position of the opening surface in the thickness direction of the substrate 2 is different between the connecting screw hole 11 and the other connecting screw hole 12.

  On the other hand, the header 4 has a rectangular parallelepiped shape, and a plurality of light emitting modules M are juxtaposed along the longitudinal direction with respect to one surface along the longitudinal direction (hereinafter referred to as the front surface). The header 4 is made of a highly heat conductive material, absorbs heat generated in the LED chip 3 when the LED chip 3 emits light, and forcibly dissipates it. The other surface (hereinafter referred to as the back surface) is attached to the header 4 in such a manner as to abut the front surface of the header 4. In order to attach the light emitting module M to the header 4, the attachment screw 13 is screwed into the header 4 through the attachment hole 10 of the substrate 2. When the header 4 is formed of a conductive material, an insulating member (not shown) is interposed between the header 4 and the substrate 2 to electrically insulate the header 4 from the light emitting module M. To do.

  Here, in the present embodiment, the following configuration is adopted so that the plurality of light emitting modules M configuring the light source unit 1 are connected in series.

  That is, as shown in FIGS. 1 and 4, a plurality of light emitting modules M are arranged in the longitudinal direction of the header 4 so as to coincide with the center line along the width direction of the substrate 2 and coupled to the header 4. The light emitting modules M adjacent in the width direction are arranged so that the positions of the covers 6 are alternately switched with respect to the center line. Moreover, one board | substrate 2 and the other cover 6 of a pair of adjacent light emitting module M are electrically connected through the connection board 5 which consists of metal plates.

  As shown in FIG. 1, the connecting plate 5 has a board connecting piece 5 a that overlaps the front surface of the substrate 2, a cover connecting piece 5 b that overlaps the front surface of the cover 6, and a length dimension corresponding to a step between the front surface of the substrate 2 and the cover 6. And a connecting piece 5c for connecting the board connecting piece 5a and the cover connecting piece 5b continuously and integrally, and by bending a metal plate formed in a strip shape from copper or a copper-based alloy. It is formed. A through hole 5d is formed in each of the substrate connection piece 5a and the cover connection piece 5b. In order to electrically connect the substrate 2 and the cover 6 between the adjacent light emitting modules M, the substrate connecting piece 5a of the connection plate 5 is overlapped on the front surface of the substrate 2 of one light emitting module M, and the cover connecting piece 6 Are stacked on the front surface of the cover 6 of the other light emitting module M, and the connection screws 14 are screwed into the connection screw holes 11 and 12 through the respective through holes 5d.

  By connecting the adjacent light emitting modules M using the connection plate 5 as described above, the substrate 2 and the cover 6 of the adjacent light emitting modules M are electrically connected to each other, and the LED chips of the plurality of light emitting modules M are connected. 3 can be connected in series. In addition, the light emitting modules M are arranged so that the positions of the covers 6 are alternately switched (in the vertical direction in FIGS. 1 and 4) with respect to the center line of the substrate 2 along the direction in which the light emitting modules M are arranged. Therefore, a plurality of light emitting modules M can be connected in series only by using the connection plate 5 having a simple shape that connects the connecting screw holes 11 and 12 adjacent to each other in the arrangement direction of the light emitting modules M. . Furthermore, since it is possible to determine an erroneous arrangement at first glance according to the positional relationship of the cover 6, the possibility of erroneous connection can be reduced.

  In the present embodiment, an example in which a plurality of light emitting modules M constituting the light source unit 1 are connected in series is shown. However, a plurality of light emitting modules M may be connected in parallel. Connections adjacent to each other in the width direction of the light emitting module M are arranged by connecting conductors (band-shaped metal plates) over the entire light emitting modules M arranged so that the positions of the covers in the respective light emitting modules M are aligned with respect to the center line along the width direction. What is necessary is just to connect between the screw holes 11 and 12 for use.

  By the way, the header 4 has the flow path 15 which flows the cooling fluid for cooling the light emitting module M so that the heat | fever of the LED chip 3 which moved to the back side of the board | substrate 2 may be absorbed from the board | substrate 2, and thermally radiated. As the cooling fluid, cooling water (not shown) having a temperature lower than that of the back surface of the substrate 2 is used. That is, the cooling water is used as a heat medium for moving the heat of the substrate 2.

  Specifically, as shown in FIG. 2, the header 4 is erected rearward from a rectangular front wall 16 that is long in one direction (the direction in which the light emitting modules M are arranged) and from both ends in the width direction of the front wall 16. A plurality of spaces (in this case, 4 in the width direction of the front wall 16) are provided in the region surrounded by the side wall 17 and the side wall 17 on the back surface of the front wall 16 and surrounded by the front wall 16 and the side wall 17. A duct body 19 having a dividing wall 18 divided into two, and a plate-like lid body 20 is covered on the back surface (upper surface in FIG. 2) of the duct body 19. The light emitting module M is attached to the front side of the front wall 16 of the duct body 19. Here, each space surrounded by the front wall 16, both side walls 17, each partition wall 18, and the lid body 20 of the duct body 19 functions as the flow path 15.

  That is, a plurality of (here, four) flow paths 15 each having a rectangular cross section are formed along the direction in which the light emitting modules M are arranged with respect to one header 4. Here, the plurality of light emitting modules M are coupled to the header 4 so that the light emitting regions are aligned on a straight line along the longitudinal direction of the header 4, and each flow path 15 allows cooling water to flow along the straight line. Each flow path 15 includes both an inflow port (not shown) through which cooling water flows from the outside of the header 4 and an outflow port (not shown) through which cooling water flows out of the header 4. It is a thing, Comprising: The path | route which flows cooling water is formed separately. The plurality of flow paths 15 are arranged on the front surface at a position near the front surface where the light emitting module M is attached in the header 4 so that heat generated in the light emitting module M is easily transmitted to the cooling water flowing through the flow path 15. It is arranged in parallel at equal intervals along.

  A packing 21 for preventing leakage of cooling water is attached to the joint between the lid 20 and the duct body 19. Here, a concave groove 22 is formed along the longitudinal direction of the duct main body 19 on the rear end surface of each side wall 17 of the duct main body 19, and packing is provided between the inner peripheral surface of the concave groove 22 and the front surface of the lid body 20. The lid 20 is attached to the duct body 19 so as to sandwich the 21. The lid 20 is coupled to the duct body 19 using, for example, screws (not shown).

  Thus, by flowing cooling water through each flow path 15 of the header 4, the heat generated in the LED chip 3 and transmitted to the substrate 2 is transmitted through the substrate 2 made of a highly heat conductive material by heat conduction, Further, heat is forcibly radiated by being absorbed by the cooling water from the back side of the substrate 2 through the header 4. Thereby, the temperature rise of LED chip 3 can be prevented and the fall of the luminous efficiency of LED chip 3 resulting from temperature rise can be suppressed.

  Here, in the present embodiment, a configuration in which a plurality of (four) flow paths 15 are formed for one header 4 as described above is adopted, so that the flow paths 15 for one header 4 are formed. Compared to the conventional configuration in which only one is formed, the area of the inner peripheral surface of the flow path 15 can be increased, and the contact area between the cooling water flowing in the flow path 15 and the header 4 can be increased. That is, the duct main body 19 of the present embodiment has a plurality of dividing walls 18, and the cooling water contacts not only the front wall 16 and the side wall 17 but also each dividing wall 18. In the same manner as the heat sink in which the contact area is increased to improve the heat dissipation efficiency, the heat dissipation efficiency can be improved by increasing the contact area with the cooling water. In other words, the heat generated in the light emitting module M is transmitted to the cooling water from the front wall 16, the side wall 17, the dividing wall 18, and the lid body 20 in the duct body 19, and as a result, the header 4 and the cooling water. And the heat exchange efficiency between the header 4 and the cooling water is improved, the heat generated in the light emitting module M is easily transferred to the cooling water, and the light emitting module M is cooled. This has the effect of improving efficiency.

  By the way, of the four flow paths 15, the two flow paths 15 arranged on one end side in the width direction (the upper end side in FIG. 1) with respect to the center of the header 4 in the width direction are the length of the header 4. 1 constitutes a first flow path 15a for flowing cooling water from the left side to the right side in FIG. 1 along one direction parallel to the direction, and two arranged on the other end side in the width direction (lower end side in FIG. 1). This flow path constitutes a second flow path 15b through which the cooling water flows in the opposite direction to the first flow path 15a (from the right side to the left side in FIG. 1). Here, since the plurality of light emitting modules M are coupled to the header 4 so that the light emitting areas are aligned, the first flow path 15a and the second flow path 15b are symmetrical with respect to the straight line. Here, two sets are formed as one set.

  Here, in the header 4, as shown in FIG. 5, a water supply port 23 a that supplies cooling water to the inlet of each first flow path 15 a, and drainage that discharges the cooling water from the outlet of each first flow path 15 a. A port 24a is provided, and further, a water supply port 23b for supplying cooling water to the inflow port of each second flow path 15b, and a drain port 24b for discharging the cooling water from the outflow port of each second flow path 15b are provided. Yes.

  That is, the inflow ports in the two first flow paths 15 a are connected to each other in the header 4 to share one water supply port 23 a, and the outflow ports of the two first flow paths 15 a are in the header 4 to each other. One drain outlet 24a is shared by being connected. Similarly, the inlets of the two second flow paths 15b are connected to each other in the header 4 to share one water supply port 23b, and the outlets of the two second flow paths 15b are connected to each other in the header 4. By connecting with each other, one drain port 24b is shared. Accordingly, as shown in FIG. 5, the water supply ports 23 a and 23 b of the header 4 are connected to the supply device 25 that supplies the cooling water to the flow path 15, and the header 4 is connected to the discharge device 26 that discharges the cooling water of the flow path 15. By connecting the respective drain outlets 24 a and 24 b, it is possible to flow cooling water through the flow paths 15 in the header 4. The supply device 25 supplies cooling water having a temperature lower than that of the back surface of the substrate 2 in the light emitting module M to each flow path 15.

  According to this configuration, although the cooling water flows from the left side to the right side in FIG. 1 in the first flow path 15a, the cooling water flows from the right side to the left side in FIG. Thus, the temperature difference in the light emitting region generated between the plurality of light emitting modules M can be reduced. Moreover, since each of the first flow path 15a and the second flow path 15b has an inlet and an outlet separately, for each of the first flow path 15a and the second flow path 15b, The cooling water that is thermally independent can be supplied, and the cooling water flowing into the first flow path 15a and the cooling water flowing into the second flow path 15b have substantially the same temperature. Therefore, the light emitting module M disposed on the upstream side of the first flow path 15a and the light emitting module M disposed on the downstream side of the first flow path 15a have a luminous efficiency due to the temperature rise of the LED chip 3 in the light emitting region. Variations can be suppressed, and a light emitting surface with less luminance unevenness can be realized.

  Note that the direction in which the cooling water flows to each flow path 15 formed in the header 4 is not limited to the above-described example. For example, the direction in which the cooling water flows in the adjacent flow paths 15 is alternately switched ( In other words, all the flow paths are arranged so that the flow paths 15 are arranged (so that the first flow paths 15a and the second flow paths 15b are alternately positioned) or the directions in which the cooling water flows in all the flow paths 15 are aligned. It is also conceivable that 15 is the first flow path 15a (or the second flow path 15b). Moreover, the number of the flow paths 15 formed in the header 4 is not limited to four, and may be plural. In the header 4, individual water supply ports and drain ports may be provided for each flow path 15.

  Further, the header 4 has a thin non-reactive layer (not shown) for preventing corrosion by cooling water on the entire inner peripheral surface of each flow path 15.

In this embodiment, aluminum nitride (AlN) which is an insulating material and has a relatively high thermal conductivity is used as the material of the header 4. However, aluminum nitride easily reacts with alkaline water, and when the light source unit 1 is used for a long time, it may be corroded by the cooling water flowing in the flow path 15. Therefore, by applying heat treatment to the inner peripheral surface of the flow path 15, a non-reactive layer made of alumina (Al ₂ O ₃ ) that hardly reacts with water is formed, and the header 4 is corroded by the cooling water flowing in the flow path 15. To prevent that. Although alumina has a lower thermal conductivity than aluminum nitride, the non-reactive layer is thin, so that the heat transfer rate to the cooling water in the flow path 15 is not significantly reduced. The non-reactive layer is not limited to the one made of alumina, and may be formed by coating the entire inner peripheral surface of the flow path 15 with, for example, a synthetic resin.

  By the way, the light source unit 1 exemplified in the present embodiment employs an LED chip 3 that emits ultraviolet rays, and is used, for example, in a printing system that cures ultraviolet curable ink. That is, the light source unit 1 is installed above a conveying means (for example, a belt conveyor) that conveys a light irradiation target (for example, printed matter), and irradiates light to the light irradiation target that passes under the light substantially uniformly. Conventionally, a xenon lamp has been mainly used for this type of light source unit 1, and in this embodiment, by using a plurality of light emitting modules M provided with a plurality of LED chips 3 arranged side by side, It achieves the light irradiation range and light quantity close to those of a xenon lamp. Here, since the plurality of light emitting modules M are coupled to the header 4 so that the light emitting areas are aligned in a straight line along the longitudinal direction of the header 4, the LED chips 3 provided in each light emitting module M can emit light. A line light source can be formed. Here, the light source unit 1 is disposed such that the longitudinal direction of the line light source intersects the transport direction of the light irradiation target. Since the length dimension of the line light source can be adjusted by the number of the light emitting modules M coupled to the header 4, the length of the line light source is adjusted according to the size of the light irradiation target (for example, about 30 to 70 cm). be able to.

  Moreover, since the light source unit 1 of the present embodiment is used in a state where a plurality of light emitting modules M are coupled to one header 4, the heat of the plurality of light emitting modules M is dissipated by one header 4. Is possible. In other words, the header 4 is shared by a plurality of light emitting modules M. Therefore, even when a plurality of light emitting modules M are used, only one header 4 is required, and maintenance of the header 4 does not become troublesome. In particular, in this embodiment, if the lid 20 is removed from the duct body 19, the cooling water flow path 15 is exposed, so that maintenance such as cleaning of the flow path 15 can be easily performed.

  Since each light emitting module M is coupled to the header 4, when the LED chip 3 becomes unable to emit light due to disconnection or the like, it can be dealt with by removing only the corresponding light emitting module M from the header 4 and replacing it. The header 4 does not need to be exchanged. Therefore, the cost required for repairing the light source unit 1 can be reduced compared to the configuration in which the header 4 must be replaced along with the replacement of the light emitting module M.

  By the way, in this embodiment, although the LED chip 3 which radiates | emits an ultraviolet-ray as an example of the light source unit 1 was employ | adopted and the light source unit 1 used for the printing system which hardens an ultraviolet curing ink etc. was demonstrated, this example The present invention can be applied to various light source units 1 using the LED chip 3. For example, if the LED chip 3 that emits visible light is used, the light source unit 1 for a display device that displays characters and images can be configured.

  The cooling fluid flowing through the flow path 15 is not limited to cooling water, but may be other liquids, cooling gas, or the like. Each flow path 15 is not limited to a rectangular cross section, and may have a triangular or circular cross section, for example. Furthermore, each flow path 15 is not limited to a straight line extending between the inflow port and the outflow port, and may have a shape meandering between the inflow port and the outflow port, for example. The header 4 is not limited to the one that can be separated into the duct body 19 and the lid body 20, but may be one in which a plurality of flow paths 15 are provided in a duct body 19 that is integrally formed.

(Embodiment 2)
The light source unit 1 of the present embodiment is different from the light source unit 1 of the first embodiment in how the cooling water flows into the flow path 15 provided in the header 4.

  That is, here, as shown in FIG. 6, the water supply port 23a of the first channel 15a is connected to the supply device 25, the drain port 24b of the second channel 15b is connected to the discharge device 26, and the first flow The drainage port 24 a of the passage 15 a and the water supply port 23 b of the second flow path 15 b are coupled to each other by the connecting pipe 27 outside the header 4. Further, a cooling device 28 for forcibly cooling the cooling water flowing in the connecting pipe 27 is provided outside the header 4. As the cooling device 28, for example, one having a structure in which cooling air is blown onto a part of the connecting pipe 27 is used.

  According to the light source unit 1 having the above-described configuration, the cooling water that has flowed through the first flow path 15a is caused to flow through the connecting pipe 27 to the second flow path 15b. By using the cooling water that flows to 15b in common, the flow rate of the cooling water is reduced as compared with the case where the cooling water is individually supplied to the first flow path 15a and the second flow path 15b as in the first embodiment. be able to. Moreover, since the cooling water is cooled by the cooling device 28 when passing through the connecting pipe 27 between the first flow path 15a and the second flow path 15b, the heat of the light emitting module M is absorbed in the first flow path 15a. Even when the temperature of the cooling water rises, low-temperature cooling water can be flowed to the second flow path 15b. Therefore, thermally independent cooling water can be supplied to each of the first flow path 15a and the second flow path 15b, and the cooling water flowing into the first flow path 15a and the second flow path. The cooling water flowing into 15b can be set to substantially the same temperature. As a result, there is almost no temperature difference in the light emitting region generated between the plurality of light emitting modules M coupled to the header 4, and the light emitting module M disposed on the upstream side of the first flow path 15a and the first flow path 15a. The light emitting module M disposed on the downstream side can suppress variation in light emission efficiency due to the temperature rise of the LED chip 3 in the light emitting region, and a light emitting surface with less luminance unevenness can be realized.

  Other configurations and functions are the same as those of the first embodiment.

It is a schematic exploded perspective view which shows the principal part of Embodiment 1 of this invention. It is a schematic sectional drawing which shows a structure same as the above. The light emitting module same as the above is shown, (a) is a schematic perspective view seen from the front side, and (b) is a schematic perspective view seen from the back side. It is a schematic front view of the principal part same as the above. It is a schematic block diagram which shows the connection state of a light source unit same as the above. It is a schematic block diagram which shows the connection state of Embodiment 2 of this invention. A prior art example is shown, (a) is a schematic sectional view, and (b) is a schematic front view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source unit 2 Board | substrate 3 Light emitting diode (LED) chip 4 Header 15 Flow path 15a 1st flow path 15b 2nd flow path 27 Connecting pipe 28 Cooling device M Light emitting module

Claims (5)

  A light emitting module having a substrate made of a highly heat conductive material and a plurality of light emitting diode chips provided on a light emitting region on one surface of the substrate, and a plurality of light emitting modules made of a heat conductive material covering the other surface of the substrate. And a header that can be coupled in contact with each other, the header having a flow path for flowing a cooling fluid for cooling the light emitting module, and a plurality of the flow paths are formed for one header. Each of the flow paths is provided with both an inflow port through which cooling fluid flows from the outside of the header and an outflow port through which cooling fluid flows out of the header.   The plurality of flow paths include a first flow path for flowing the cooling fluid along a direction in which the light emitting regions of the plurality of light emitting modules are arranged, and the light emission when the cooling fluid is flowed in the first flow path. 2. The light source unit according to claim 1, wherein the light source unit includes at least one combination with a second flow path through which a cooling fluid flows so as to reduce a temperature difference between light emitting regions generated between modules.   The plurality of light emitting modules are coupled to the header such that the light emitting regions are aligned, and the second flow path is disposed symmetrically with the first flow path with respect to the straight line. The light source unit according to claim 2, wherein the cooling fluid is allowed to flow in a direction opposite to the one flow path.   The outflow port of the first flow path and the inflow port of the second flow path are coupled to each other by a connecting pipe outside the header, and a cooling fluid flowing in the connecting pipe is placed outside the header. The light source unit according to claim 2, wherein a cooling device for forcibly cooling is provided.   The header is made of aluminum nitride, and has a thin non-reactive layer that prevents corrosion by the cooling fluid over the entire inner peripheral surface of the flow path. The light source unit according to any one of 4.

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