Light source unit and light irradiation device

Abstract

A light source unit includes a plurality of LED elements; an LED substrate that comprises a plurality of subdivided regions arrayed in a circumferential direction at least at an outwardmost locus as viewed from a direction perpendicular to the mounting surface; and cooling member(s) which are provided at surface(s) on a side opposite the mounting surface of the LED substrate and at which provided at each of the plurality of subdivided regions there are inlet port(s) for flow thereinto of cooling medium for cooling LED element(s), outlet port(s) that are for discharge of cooling medium and that are disposed more toward a center of the LED substrate than inlet port(s) as viewed from the direction perpendicular to the mounting surface of the LED substrate, and flow passage(s) which connect inlet port(s) and outlet port(s) and through interior(s) of which cooling medium flows.

Claims

1. A light source unit that causes a workpiece to be irradiated with light, the light source unit being characterized in that it comprises: a plurality of LED elements; an LED substrate that has a mounting surface on which the plurality of LED elements are mounted and that comprises a plurality of subdivided regions arrayed in a circumferential direction at least at an outwardmost locus as viewed from a direction perpendicular to the mounting surface; and a cooling member which is provided at a surface on a side opposite the mounting surface of the LED substrate and at which provided at each of the plurality of subdivided regions there are an inlet port for flow thereinto of cooling medium for cooling the LED elements, an outlet port that is for discharge of the cooling medium and that is disposed more toward a center of the LED substrate than the inlet port as viewed from the direction perpendicular to the mounting surface of the LED substrate, and a flow passage which connects the inlet port and the outlet port and through an interior of which the cooling medium flows.

2. The light source unit according to claim 1 characterized in that arranged at the LED substrate there are a plurality of substrate subsets at which the subdivided regions are respectively formed.

3. The light source unit according to claim 1 characterized in that the flow passage is constituted so as to be directed toward the center from a location toward a perimeter edge portion as viewed from the direction perpendicular to the mounting surface of the LED substrate.

4. The light source unit according to claim 1 characterized in that, as viewed from the direction perpendicular to the mounting surface of the LED substrate, the inlet port appears to overlap at least one of that or those among the LED elements which constitute an outer edge of a region in which the LED elements are arranged.

5. The light source unit according to claim 1 characterized in that, as viewed from the direction perpendicular to the mounting surface of the LED substrate, the plurality of subdivided regions are constituted so as to have rotational symmetry about the center of the LED substrate.

6. The light source unit according to claim 5 characterized in that, as viewed from the direction perpendicular to the mounting surface of the LED substrate, the plurality of subdivided regions are constituted so as to have point symmetry with respect to the center of the LED substrate.

7. The light source unit according to claim 1 characterized in that, as viewed from the direction perpendicular to the mounting surface of the LED substrate, the flow passages are constituted so as to have point symmetry with respect to the center of the LED substrate.

8. The light source unit according to claim 1 characterized in that a primary component of a material of the LED substrate is aluminum nitride or silicon nitride.

9. The light source unit according to claim 1 characterized in that formed at the mounting surface of the LED substrate are a first region, and a second region which is more toward the center of the LED substrate than the first region and at which a density with which the LED elements are arranged is less than that at the first region.

10. The light source unit according to claim 2 characterized in that the flow passage is constituted so as to be directed toward the center from a location toward a perimeter edge portion as viewed from the direction perpendicular to the mounting surface of the LED substrate.

11. The light source unit according to claim 2 characterized in that, as viewed from the direction perpendicular to the mounting surface of the LED substrate, the inlet port appears to overlap at least one of that or those among the LED elements which constitute an outer edge of a region in which the LED elements are arranged.

12. The light source unit according to claim 3 characterized in that, as viewed from the direction perpendicular to the mounting surface of the LED substrate, the inlet port appears to overlap at least one of that or those among the LED elements which constitute an outer edge of a region in which the LED elements are arranged.

13. The light source unit according to claim 10 characterized in that, as viewed from the direction perpendicular to the mounting surface of the LED substrate, the inlet port appears to overlap at least one of that or those among the LED elements which constitute an outer edge of a region in which the LED elements are arranged.

14. The light source unit according to claim 2 characterized in that formed at the mounting surface of the LED substrate are a first region, and a second region which is more toward the center of the LED substrate than the first region and at which a density with which the LED elements are arranged is less than that at the first region.

15. The light source unit according to claim 3 characterized in that formed at the mounting surface of the LED substrate are a first region, and a second region which is more toward the center of the LED substrate than the first region and at which a density with which the LED elements are arranged is less than that at the first region.

16. The light source unit according to claim 10 characterized in that formed at the mounting surface of the LED substrate are a first region, and a second region which is more toward the center of the LED substrate than the first region and at which a density with which the LED elements are arranged is less than that at the first region.

17. A light irradiation device characterized in that it comprises: a chamber that contains the workpiece; a support member that supports the workpiece within the chamber; and the light source unit according to claim 1 that causes light directed toward the workpiece to be irradiated therefrom.

18. The light irradiation device according to claim 17 characterized in that the light source unit is arranged outside the chamber.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a schematic sectional view of the constitution of an embodiment of a light irradiation device as seen in the Y direction.

(2) FIG. 2 is a schematic view of an LED substrate as seen from a location at the −Z side thereof.

(3) FIG. 3 is a view of cooling members as seen from a location at the +Z side thereof.

(4) FIG. 4 is a schematic view of an LED substrate in an embodiment of a light irradiation device as seen from a location at the −Z side thereof.

(5) FIG. 5 is a view of cooling members as seen from a location at the +Z side thereof.

(6) FIG. 6 is a schematic view of an LED substrate in an embodiment of a light irradiation device as seen from a location at the −Z side thereof.

(7) FIG. 7 is a view of cooling members as seen from a location at the +Z side thereof.

(8) FIG. 8 is a schematic view of cooling members in another embodiment of a light irradiation device as seen from a location at the +Z side thereof.

(9) FIG. 9 is a schematic view of cooling members in another embodiment of a light irradiation device as seen from a location at the +Z side thereof.

(10) FIG. 10 is a schematic view of cooling members in another embodiment of a light irradiation device as seen from a location at the +Z side thereof.

(11) FIG. 11 is a schematic view of cooling members in another embodiment of a light irradiation device as seen from a location at the +Z side thereof.

(12) FIG. 12 is a schematic drawing showing exemplary LED substrates mounted in a conventional light irradiation device for thermal treatment.

(13) FIG. 13 is a schematic drawing showing exemplary LED substrates mounted in a conventional light irradiation device for thermal treatment.

(14) FIG. 14 is a sectional view showing in schematic fashion an exemplary constitution of a conventional light irradiation device.

(15) FIG. 15 is a sectional view showing in schematic fashion an exemplary constitution of a conventional light irradiation device.

EMBODIMENTS FOR CARRYING OUT INVENTION

(16) Below, light irradiation devices in accordance with the present invention are described with reference to the drawings. As the following respective drawings related to light irradiation devices are all mere schematic representations thereof, note that the dimensional ratios and numbers of items shown in the drawings are not necessarily consistent with actual dimensional ratios and numbers of items.

First Embodiment

(17) FIG. 1 is a schematic sectional view of the constitution of an embodiment of a light irradiation device 1 as seen in the Y direction. As shown in FIG. 1, the light irradiation device 1 of the first embodiment is provided with a light source unit 2, a chamber 10 which contains workpiece W1, and a supply mechanism 15; the light source unit 2 is provided with a plurality of LED elements 11, and an LED substrate 12 on which LED elements 11 are mounted.

(18) At the description which follows, as shown in FIG. 1, description will be given with reference to a Z direction which is in the direction in which the LED substrate 12 and workpiece W1 are mutually opposed; an X direction which is in the direction in which a pair of support members 13, described below, are mutually opposed; and a Y direction which is in a direction perpendicular to the X direction and the Z direction.

(19) Furthermore, similarly, in referring to directions below, where a distinction is to be made between positive and negative senses of a direction, this will be indicated by appending a plus or minus sign thereto as in the “+Z direction” and the “−Z direction”; where no distinction is to be made between positive and negative senses of a direction, reference will be made to simply the “Z direction”.

(20) As shown in FIG. 1, the chamber 10 is provided with a pair of support members 13 that support workpiece W1 at a location inward therefrom. Support members 13 support workpiece W1 in such fashion that the principal plane W1a of the workpiece W1 is arranged in the XY plane.

(21) Note that it is sufficient that support of workpiece W1 by support member(s) 13 be such as will cause the principal plane W1a thereof to be arranged in the XY plane, for example, support members 13 may be provided with a plurality of pin-like projections such that workpiece W1 is supported in point-like fashion by those projections. Here, principal plane W1a is where circuit elements, wiring, and so forth are formed, being the plane from which the light emitted by LED elements 11 is irradiated.

(22) Furthermore, the chamber 10 is provided, at a wall toward the +Z side thereof, with light-transmissive window 10a, which is for capturing, at a location inward therefrom, light emitted from LED elements 11, and through which the light emitted from LED elements 11 passes. As shown in FIG. 1, light-transmissive window 10a with which the chamber 10 is provided is constituted so as to be opposed to principal plane W1a of workpiece W1 which is supported by support members 13. In other words, light emitted from LED elements 11 irradiates principal plane W1a of workpiece W1 by way of light-transmissive window 10a.

(23) Note that the LED substrate 12 may be arranged within the chamber 10, and the chamber 10 may not be provided with light-transmissive window 10a. Furthermore, any desired shape may be employed for the shape of the chamber 10 as seen in the Z direction might, it being possible, for example, for this to be circular, elliptical, polygonal, or the like.

(24) As shown in FIG. 1, the supply mechanism 15 is connected by tubular plumbing 15a to outlet ports 12q and inlet ports 12p of cooling members 12z provided at surfaces on the +Z side of the LED substrate 12. As indicated by the arrow shown in single-dash chain line at FIG. 1, the supply mechanism 15 causes liquid coolant C1 to flow into inlet ports 12p, and receives liquid coolant C2 that has been made to flow through the flow passages 12c formed in cooling members 12z to be discharged from outlet ports 12q. Note that the flow passages 12c are shown in FIG. 3, described below.

(25) From the standpoint of heat dissipating efficiency, it is preferred that cooling members 12z be members fabricated such that the primary component thereof is a material such as aluminum or copper having high thermal conductivity. While cooling members 12z are shown in FIG. 1 as being planar members of the same thickness as the LED substrate 12, depending on heat dissipating efficiency, the constitution in terms of arrangement of LED elements 11, and so forth, the cooling members 12z may be ring-shaped member(s), block-shaped member(s), or any other such desired shape(s).

(26) Note that while the first embodiment is described in terms of a constitution in which cooling is carried out by causing water coolant serving as cooling medium to flow through flow passages 12c of cooling members 12z, it is also possible to employ a cooling medium other than water, such as, for example, a fluorinated inert liquid or the like.

(27) Furthermore, whereas the first embodiment of the light irradiation device 1 is constituted such that liquid coolant C2 discharged from outlet ports 12q is made to return to supply mechanism 15, however, the liquid coolant C2 may be discharged to the exterior of the light irradiation device 1.

(28) FIG. 2 is a schematic view of the LED substrate 12 as seen from a location at the −Z side thereof. As shown in FIG. 2, as viewed in the Z direction, the LED substrate 12 is such that substrate subsets 12n are arrayed in the circumferential direction in such fashion as to be point symmetric about center 12f of the LED substrate 12. A plurality of LED elements 11 are arranged in array-like fashion on mounting surface 12b of the LED substrate 12 which is arranged so as to oppose principal plane W1a of workpiece W1 which is supported by support members 13.

(29) Furthermore, as mentioned above with reference to FIG. 14 and FIG. 15, with the goal of increasing the uniformity of the distribution of light with which workpiece W1 is irradiated, the plurality of LED elements 11 are arranged in such fashion that the density with which these are arranged is greater at the periphery of perimeter edge portion 12e of the LED substrate 12. In other words, formed thereat are a first region A1 which is toward perimeter edge portion 12e, and a second region A2 which is toward center 12f and at which the density with which LED elements 11 are arranged is less than that at first region A1.

(30) From the standpoints of the heat dissipating characteristics of LED elements 11 and ensuring the uniformity of the light with which workpiece W1 is irradiated, it is preferred that the plurality of LED elements 11 mounted on mounting surface 12b of the LED substrate 12 be arranged such that the distances separating them be 1.0 mm to 5.0 mm, and it is more preferred that they be arranged such that the distances separating them be 1.5 mm to 3.0 mm.

(31) FIG. 3 is a view of cooling members 12z as seen from a location at the +Z side thereof; and while in reality they would not actually be visible, exemplary flow passages 12c which are formed toward the interior from cooling members 12z and through which liquid coolant C1 flows, and a portion of LED elements 11a forming the outer edge of a region in which LED elements 11 are arranged, are shown in broken line. As shown in FIG. 2 and FIG. 3, the LED substrate 12 and cooling members 12z exhibit identical shapes. Cooling members 12z are arranged so as to respectively correspond to the LED substrate 12 which is made up of four substrate subsets 12n, the shapes of flow passages 12c all appearing to be the same when cooling members 12z are viewed in the Z direction.

(32) As the primary component of the material for the LED substrate 12 on which LED elements 11 are mounted, which is an insulated material metal oxides, metal nitrides, and other such ceramics may be employed, which has a high thermal conductivity aluminum nitride and silicon nitride being particularly preferred therefor.

(33) As shown in FIG. 3, the flow passage 12c is directed toward center 12f from a location toward perimeter edge portion 12e in such fashion as to connect the inlet port 12p and the outlet port 12q which is provided toward center 12f of the LED substrate 12 from the inlet port 12p. Furthermore, as seen when all of cooling members 12z are viewed collectively, the flow passages 12c are constituted so as to have point symmetry with respect to center 12f of the LED substrate 12. In addition, inlet ports 12p are formed in such fashion that, as viewed in the Z direction, they appear to overlap those LED elements 11a which constitute the outer edge of the region in which LED elements 11 are arranged as shown in FIG. 2.

(34) Whereas the flow passage 12c is formed so as to be directed toward center 12f from a location toward perimeter edge portion 12e, however, the flow passage 12c may be made to include portion(s) routed so as to be directed toward perimeter edge portion 12e from location(s) toward center 12f. Furthermore, as mentioned above, the flow passage 12c may be constituted by tubular member(s) installed on the surface of the LED substrate 12 which is opposite the side thereof on which LED elements 11 are mounted.

(35) As a result of adoption of the foregoing constitution, liquid coolant C1, which is in a state such that the temperature thereof is low, is made to flow into respective inlet ports 12p from supply mechanism 15. In addition, liquid coolant C1 which flows thereinto by way of respective inlet ports 12p flows not through the entire LED substrate 12 but through the flow passages 12c at the respective substrate subsets 12n into which the entirety is divided. For this reason, as the flow passages 12c through which liquid coolant C1 flows are shorter than would be the case were these such as to cause flow through a single common cooling member 12z, liquid coolant C1 tends to arrive at outlet ports 12q before it would reach an elevated temperature.

(36) Furthermore, as liquid coolant C1 is made to flow from supply mechanism 15 into respective inlet ports 12p, the LED substrate 12 is cooled in point symmetric fashion. For this reason, in the circumferential direction of the LED substrate 12, there is no occurrence of a temperature gradient of the sort in which temperature might otherwise have been made to gradually increase were this have been made to describe the locus of a full revolution about the center 12f of the LED substrate 12. Accordingly, overall nonuniformity in the temperature of the LED substrate 12 is suppressed, overall uniformity in the radiance of LED elements 11 is improved, and irradiative nonuniformity in the light with which workpiece W1 is irradiated is suppressed.

(37) Moreover, as shown in FIG. 3, as a result of adoption of a constitution in which liquid coolant C1 is made to flow so as to be directed toward center 12f from locations toward perimeter edge portion 12e, liquid coolant C1 which is in a state such that the temperature thereof is low is able to absorb a greater amount of heat at locations toward perimeter edge portion 12e which is toward the upstream side of flow passages 12c. As a result, locations toward perimeter edge portion 12e of the LED substrate 12 are subjected to prioritized cooling, differences in temperature between locations toward center 12f and locations toward perimeter edge portion 12e are reduced, and uniformity in the overall temperature distribution of the LED substrate 12 is further improved.

(38) While the LED substrate 12 of the light irradiation device 1 in accordance with the first embodiment is constituted from four substrate subsets 12n, however, the LED substrate 12 may be constituted from two substrate subsets 12n, or to an embodiment in which this is constituted from six or more substrate subsets 12n.

(39) Furthermore, the LED substrate 12 and the respective substrate subsets 12n may be shaped as seen in the Z direction are hexagonal, octagonal, or other such polygonal shape.

(40) To reduce the size of the overall device, the light irradiation device 1 may be provided with plumbing in the form of a plate in which passages for distribution of liquid are formed instead of tubular plumbing 15a. Because plumbing in the form of a plate would not require as much space for arrangement thereof as would tubular plumbing 15a, employment thereof would make it possible to reduce the overall size of the light irradiation device 1.

(41) Furthermore, the flow passage 12c may be formed so as to have portion(s) at which flow is directed toward perimeter edge portion 12e from location(s) toward center 12f.

(42) Moreover, the inlet port 12p may be such that, as viewed in the Z direction, it does not appear to overlap those LED elements 11a which constitute the outer edge of the region in which LED elements 11 are arranged.

Second Embodiment

(43) The constitution of a second embodiment of the light irradiation device 1 in accordance with the present invention will be described with emphasis on the differences from the first embodiment.

(44) FIG. 4 is a schematic view of the LED substrate 12 in an embodiment of the light irradiation device 1 as seen from a location at the −Z side thereof. As shown in FIG. 4, the light irradiation device 1 of the second embodiment is such that the LED substrate 12 is constituted from substrate subset 12n which exhibits the shape of a single circle, and four substrate subsets 12n constituted so as to be arrayed in the circumferential direction so as to surround the substrate subset 12n. When viewed in its entirety, the LED substrate 12 has point symmetry with respect to center 12f.

(45) At the second embodiment, as shown in FIG. 4, a plurality of LED elements 11 are arranged in such fashion that the density with which they are arranged is approximately the same at each of the substrate subsets 12n.

(46) FIG. 5 is a view of cooling members 12z as seen from a location at the +Z side thereof; and, in similar fashion as at FIG. 3, while in reality they would not actually be visible, exemplary the flow passages 12c which are formed toward the interior and through which liquid coolant C1 (see FIG. 1) flows are shown in broken line.

(47) Below, description of flow passage 12c for liquid coolant C1 at the second embodiment will be given in terms of the example of cooling member 12z which is provided at substrate subset 12n which corresponds to a portion thereof. At the LED substrate 12 of the second embodiment, liquid coolant C1 is made to flow from supply mechanism 15 into the respective inlet ports 12p of the four substrate subsets 12n which are arranged at the outside circumference thereof. In addition, liquid coolant C1 flows through flow passages 12c of substrate subsets 12n at the outside circumference thereof.

(48) Liquid coolant C1 that has flowed through flow passages 12c of substrate subsets 12n at the outside circumference thereof is discharged from outlet ports 12q. Liquid coolant C1 that has been discharged from outlet ports 12q is made to flow into the inlet port 12p of the central substrate subset 12n by way of tubular plumbing (see FIG. 1).

(49) The central substrate subset 12n is provided with one outlet port 12q for the four inlet ports 12p. Liquid coolant C1 which flows into the respective inlet ports 12p of the central substrate subset 12n flows through respective flow passages 12c and comes together at the outlet port 12q where it is discharged as liquid coolant C2 (not shown).

(50) Whereas at FIG. 5 the outlet port 12q is constituted such that it is larger than inlet ports 12p so as to allow liquid coolant C1 which flows thereinto from respective inlet ports 12p to all be discharged together by way of a single outlet port 12q, however, the inlet ports 12p and the outlet port 12q may be configured in any size.

(51) Thus, liquid coolant C1 flows into the respective substrate subsets 12n by way of inlet ports 12p, is made to flow through flow passages 12c of the central substrate subsets 12n, and is discharged as liquid coolant C2 by way of the outlet port 12q.

(52) Here, the electric power supplied thereto may be controlled so as to cause the respective substrate subsets 12n to be such that radiance of LED element(s) 11 mounted on substrate subset(s) 12n toward center 12f is less than radiance of LED element(s) 11 mounted on substrate subset(s) 12n toward perimeter edge portion 12e.

(53) By carrying out control in such fashion, it will be possible without adjusting the density with which LED elements 11 are arranged to suppress occurrence of a difference in intensity of the light which irradiates locations toward perimeter edge portion W1e versus that which irradiates locations toward central portion W1c at principal plane W1a of workpiece W1 such as was described above with reference to FIG. 15.

(54) However, where the aforementioned control of the electric power supplied thereto is carried out, because the electric power which is supplied to LED element(s) 11 arranged at substrate subset(s) 12n toward perimeter edge portion 12e will be greater than that which is supplied to LED element(s) 11 arranged at substrate subset(s) 12n toward center 12f, locations on the LED substrate 12 toward perimeter edge portion 12e will be higher in temperature.

(55) As shown in FIG. 5, as a result of adoption of a constitution in which liquid coolant C1 is made to flow so as to be directed toward center 12f from locations toward perimeter edge portion 12e, liquid coolant C1 which is in a state such that the temperature thereof is low is able to absorb a greater amount of heat at locations toward perimeter edge portion 12e which is toward the upstream side of the flow passages 12c. This being the case, locations toward perimeter edge portion 12e of the LED substrate 12 are subjected to prioritized cooling, differences in temperature between locations toward center 12f and locations toward perimeter edge portion 12e are reduced, and uniformity in the overall temperature distribution of the LED substrate 12 is further improved.

(56) Moreover, the liquid coolant C1 may be made to flow directly into inlet ports 12p of central substrate subset 12n from the supply mechanism 15, and liquid coolant C2 may be discharged from outlet ports 12q at all of the substrate subsets 12n.

(57) Furthermore, the LED substrate 12 may be such that the central substrate subset 12n is eliminated, and a plurality of substrate subsets 12n which form perimeter edge portion 12e may be constituted in annular fashion. For example, by causing the central region of the LED substrate 12 to be provided with a hole, this will make it possible for a radiation thermometer to be provided such as will permit observation of the surface temperature of workpiece W1 by way of the hole. Hole(s) for radiation thermometric observation may be provided at any among the plurality of substrate subsets 12n.

Third Embodiment

(58) The constitution of a third embodiment of the light irradiation device 1 in accordance with the present invention will be described with emphasis on the differences from the first embodiment and the second embodiment.

(59) FIG. 6 is a schematic view of the LED substrate 12 in an embodiment of the light irradiation device 1 as seen from a location at the −Z side thereof. As shown in FIG. 6, light irradiation device 1 of the third embodiment is such that the LED substrate 12 is constituted from a square-shaped substrate subset 12n, and eight substrate subsets 12n arrayed in the circumferential direction so as to surround the square-shaped substrate subset 12n.

(60) The LED substrate 12 of the third embodiment includes three types of shapes, and while the shapes of the respective flow passages 12c are different, when viewed from the perspective of the overall the LED substrate 12 substrate subsets 12n and the flow passages 12c have point symmetry with respect to center 12f.

(61) FIG. 7 is a view of cooling members 12z as seen from a location at the +Z side thereof; and, in similar fashion as at FIG. 3, while in reality they would not actually be visible, the exemplary flow passages 12c which are formed toward the interior and through which liquid coolant C1 flows are shown in broken line.

(62) Below, description of the flow passage 12c for liquid coolant C1 at the third embodiment will be given in terms of the example of the substrate subset 12n which corresponds to a portion thereof. The third embodiment is such that liquid coolant C1 respectively flows from the supply mechanism 15 into inlet ports 12p of cooling members 12z provided at the eight substrate subsets 12n arranged at the outside circumference. In addition, liquid coolant C1 flows through the flow passages 12c of cooling members 12z provided at substrate subsets 12n at the outside circumference thereof.

(63) Liquid coolant C1 that has flowed through the flow passages 12c of cooling members 12z at the outside circumference thereof is discharged from outlet ports 12q. Liquid coolant C1 that has been discharged from outlet ports 12q is made to flow into inlet ports 12p at a cooling member 12z provided at the central substrate subset 12n by way of tubular plumbing (see FIG. 1).

(64) Here, the third embodiment is constituted such that whereas there are eight outlet ports 12q at the cooling members 12z at the outside circumference, there are four inlet ports 12p at the central cooling member 12z. In this regard, adjustment in terms of combination or bifurcation of liquid coolant C1 is accomplished by means of the tubular plumbing that connects inlet ports 12p at the central cooling member 12z with outlet ports 12q at the cooling members 12z at the outside circumference.

(65) Liquid coolant C1 that has flowed into inlet ports 12p at the central cooling member 12z is made to flow through the flow passages 12c of the central cooling member 12z, and is discharged from an outlet port 12q as liquid coolant C2.

(66) Thus, liquid coolant C1 flows into the respective cooling members 12z by way of inlet ports 12p, is made to flow through flow passages 12c, and is discharged as liquid coolant C2 by way of the outlet port 12q.

(67) Note that the liquid coolant C1 may be made to flow directly into inlet ports 12p of the central cooling member 12z from the supply mechanism 15, and the liquid coolant C2 may be discharged from outlet ports 12q at all of the cooling members 12z.

Other Embodiments

(68) Below, description is given with respect to other embodiments.

(69) (1) FIG. 8 and FIG. 9 are schematic views of cooling members 12z of the light irradiation devices 1 in other embodiments as seen from a location at the +Z side thereof; and, in similar fashion as at FIG. 3, while in reality they would not actually be visible, the exemplary flow passages 12c which are formed toward the interior and through which liquid coolant C1 flows are shown in broken line. As shown in FIG. 8, as viewed in the Z direction, substrate subsets 12n which make up the LED substrate 12 may be not such that the LED substrate 12 overall is point symmetric but may be such that they match the arrangement obtained when rotated 120° (360°/3) about center 12f of the LED substrate 12, which is to say that they have rotational symmetry with respect thereto.

(70) Note that whereas an example of a constitution made up of three substrate subsets 12n is shown at FIG. 8, the LED substrate 12 may be constituted such that it is made up of four or more substrate subsets 12n. Furthermore, the respective substrate subsets 12n that form perimeter edge portion 12e may not be of the same shape, such as was the case with the constitution of the third embodiment shown in FIG. 6 and FIG. 7.

(71) Furthermore, as shown in FIG. 9, at the overall the LED substrate 12, taking center 12f of the LED substrate 12 to be the origin, the flow passages 12c may be constituted so as to have line symmetry about the Y axis, and may be constituted so as not to have point symmetry or rotational symmetry about center 12f.

(72) (2) FIG. 10 and FIG. 11 are schematic views of the LED substrates 12 of the light irradiation devices 1 in other embodiments as seen from a location at the +Z side thereof; and, in similar fashion as at FIG. 3, while in reality they would not actually be visible, the exemplary flow passage(s) 12c which are formed toward the interior and through which liquid coolant C1 flows are shown in broken line. FIG. 11 and FIG. 12 are each such that the LED substrate 12 is constituted from a single substrate, these each, as viewed in the Z direction, being provided with a plurality of subdivided regions 12r, each of which is provided with inlet port(s) 12p, outlet port(s) 12q, and flow passage(s) 12c.

(73) (3) It should be understood that the foregoing constitutions possessed by the light irradiation devices 1 that have been described above are merely exemplary, and the present invention is not to be limited by the respective constitutions shown in the drawings.