Light irradiation device and printing device

Abstract

To achieve miniaturization, simplification of a structure, reduction of a failure and improvement in the cooling performance in a light irradiation device.SOLUTION: A light irradiation device comprises a light source, a heat dissipation member, a drive unit, and a rectangular parallelepiped housing. The housing accommodates the light source, the heat dissipation member, and the drive unit. The housing has a first external surface, a second external surface disposed on the side opposite to the first external surface, a third external surface, a fourth external surface disposed on the side opposite to the third external surface, a fifth external surface, and a sixth external surface disposed on the side opposite to the fifth external surface. The housing has first to third openings. The first opening opens at least in the first external surface and allows light from the light source to pass therethrough. The second opening opens in a region on the first external surface side of the third external surface. The third opening opens in a region from the second external surface to a portion on the second external surface side of the third external surface. The heat dissipation member includes a base part and a plurality of projections. Each of the projections projects from the base part toward the second external surface. The light source is positioned on the first external surface side of the base part. A plurality of gaps between the plurality of projections are adjacent to the second opening.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a light irradiation device and a printing device. [Background technology]

[0002] Among light irradiation devices, there is a light irradiation device in which a light source and a board for driving the light source are housed in a housing (see, for example, the descriptions in Patent Documents 1 and 2).

[0003] In this light irradiation device, a lamp or a light emitting diode (LED) that emits light in a specific wavelength range, such as ultraviolet or infrared, is used as a light source. This light irradiation device is applied to a printing device that performs printing on a recording medium (also called a print medium) such as paper using a photocurable ink such as an ultraviolet curable ink (also called UV ink) that hardens (also called photocuring) when irradiated with ultraviolet light. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-202346 A [Patent Document 2] Patent No. 6761148 Summary of the Invention [Problem to be solved by the invention]

[0005] There is room for improvement in the light irradiation device in terms of achieving both miniaturization, simplification of structure, reduction of breakdowns, and improvement of cooling performance. [Means for solving the problem]

[0006] A light irradiation device and a printing device are disclosed.

[0007] One aspect of the light irradiation device includes a light source, a heat dissipation member, a drive unit, and a rectangular parallelepiped housing, and does not have a blower unit inside the housing, at a position in contact with the outside of the housing, or at an opening of the housing. The light source includes a plurality of light-emitting elements. The heat dissipation member is thermally connected to the light source. The drive unit includes a drive circuit that drives the light source. The housing houses the light source, the heat dissipation member, and the drive unit. The housing has a first outer surface, a second outer surface, a third outer surface, a fourth outer surface, a fifth outer surface, and a sixth outer surface. The first outer surface is a rectangular surface. The second outer surface is a rectangular outer surface of the housing on the opposite side to the first outer surface. The third outer surface is a rectangular outer surface that connects the first outer surface and the second outer surface of the housing. The fourth outer surface is a rectangular outer surface that connects the first outer surface and the second outer surface of the housing and is opposite to the third outer surface. The fifth outer surface is a rectangular outer surface that connects the first outer surface and the second outer surface of the housing and connects the third outer surface and the fourth outer surface. The sixth outer surface is a rectangular outer surface that connects the first outer surface and the second outer surface of the housing, connects the third outer surface and the fourth outer surface of the housing, and is opposite to the fifth outer surface. The housing has a first opening, a second opening, and a third opening. The first opening is open at least on the first outer surface and passes light from the light source. The second opening is open in a region of the third outer surface on the first outer surface side, connects the internal space and the external space of the housing, and serves as an air intake from the external space to the internal space. The third opening is open on each of the second and third outer surfaces in a region extending from the second outer surface to the portion of the third outer surface on the second outer surface side, connects the internal space to the external space, and serves as an exhaust port from the internal space to the external space. The heat dissipation member includes a base portion and a plurality of protrusions. The base portion is located in a region of the internal space on the first outer surface side. The plurality of protrusions each protrude from the base portion toward the second outer surface along a first direction from the first outer surface toward the second outer surface.The light source is located on the first outer surface side of the base portion. A plurality of gaps between the plurality of protrusions are adjacent to the second opening. The drive unit is located between the plurality of protrusions and the second outer surface in the internal space. The first outer surface is disposed in a downward orientation, and air is discharged from the external space to the external space by passing through the second opening, the internal space, and the third opening in this order.

[0008] One aspect of the printing device includes the light irradiation device of the above aspect, a transport unit, and a printing unit. The transport unit transports a print medium onto which light from the first opening is irradiated in a second direction that is a direction from the third outer surface toward the fourth outer surface or a direction from the fourth outer surface toward the third outer surface. The printing unit is located on the third direction side opposite to the second direction of the light irradiation device. The first outer surface is located facing downward. Effect of the Invention

[0009] It is possible to achieve a reduction in size, a simplification of the structure, a reduction in malfunctions, and an improvement in cooling performance in the light irradiation device. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a front view showing the appearance of an example of a light irradiation device according to the first embodiment. [Diagram 2] FIG. 2 is a left side view showing the appearance of an example of the light irradiation device according to the first embodiment. [Diagram 3] FIG. 3 is a right side view showing the appearance of an example of the light irradiation device according to the first embodiment. [Figure 4] FIG. 4 is a plan view illustrating an external appearance of an example of the light irradiation device according to the first embodiment. [Diagram 5] FIG. 5 is a bottom view illustrating the appearance of an example of the light irradiation device according to the first embodiment. [Figure 6] FIG. 6 is a perspective view illustrating an external appearance of an example of the light irradiation device according to the first embodiment. [Figure 7]FIG. 7 is a perspective view illustrating an external appearance of an example of the light irradiation device according to the first embodiment. [Figure 8] FIG. 8 is a cross-sectional view that illustrates an example of a virtual cross section of the light irradiation device taken along the position VIII-VIII in FIGS. 2 to 5, viewed in the +Y direction. [Figure 9] FIG. 9 is a left side view showing the appearance of an example of a heat dissipation member. [Figure 10] FIG. 10 is a front view showing the appearance of an example of a heat dissipation member. [Figure 11] FIG. 11 is a cross-sectional view illustrating a schematic diagram of an air flow path in an example of the light irradiation device according to the first embodiment. [Figure 12] FIG. 12 is a diagram showing an example of the relationship between the lighting time of an LED element, the temperature of the LED element, and the illuminance of the LED light, obtained by an experiment. [Figure 13] FIG. 13 is a left side view showing the appearance of an example of a light irradiation device in which the height of the second opening in the first direction is the first height. [Figure 14] FIG. 14 is a left side view showing the appearance of an example of a light irradiation device in which the height of the second opening in the first direction is the second height. [Figure 15] FIG. 15 is a left side view showing the appearance of an example of a light irradiation device in which the height of the second opening in the first direction is a third height. [Figure 16] FIG. 16 is a diagram showing an example of the results of a simulation regarding the relationship between the height of the second opening and the temperature reached by the LED element when the LED element is lit. [Figure 17] FIG. 17 is a diagram illustrating a schematic configuration of an example of a printing apparatus according to the first embodiment. [Figure 18] FIG. 18 is a plan view showing an example of the form of four types of ink attached to the upper surface of a print medium. [Figure 19] FIG. 19 is a front view showing an example of a light irradiation device fixed to a fixed portion of a printing device. [Figure 20] FIG. 20 is a right side view showing the appearance of a light irradiation device according to another example of the first embodiment. [Figure 21] FIG. 21 is a right side view showing the appearance of another example of the heat dissipation member. [Figure 22] FIG. 22 is a front view showing the appearance of another example of a heat dissipation member. [Diagram 23] FIG. 23 is a front view showing another example of a light irradiation device fixed to a fixed portion of a printing device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] There is a light irradiation device that houses a light source and a board for driving the light source in a housing. In this light irradiation device, a lamp or a light emitting diode (LED) that emits light in a specific wavelength range, such as ultraviolet or infrared, is used as the light source.

[0012] This light irradiation device can be applied to a printing device that prints on a print medium such as paper using light-curable ink such as ultraviolet-curable ink (UV ink) that hardens (photocures) when irradiated with ultraviolet light. In this printing device, for example, a form in which ultraviolet light is irradiated by the light irradiation device onto dot-shaped UV ink formed on the print medium by an inkjet method or the like is considered.

[0013] However, in the above-mentioned light irradiation device, heat is generated in the light source and the electronic components on the board when light is emitted. For this reason, it is conceivable to cool the light source and the electronic components using, for example, a heat dissipation member (also called a heat sink) and a cooling fan.

[0014] However, for example, providing a cooling fan may lead to an increase in size of the light irradiation device and a complex structure. In addition, for example, the cooling fan that rotates may break down. In addition, for example, in a printing device, if a cooling fan causes a disturbance in the forced air flow, it may affect the ejection of UV ink onto a print medium by an inkjet method or the like, and the landing of UV ink droplets on the print medium.

[0015] For this reason, there is room for improvement in the light irradiation device in terms of achieving both miniaturization, simplification of structure, reduction of breakdowns, and improvement of cooling performance.

[0016] Therefore, the inventors of the present disclosure have created a technology for a light irradiation device that can achieve both miniaturization, simplification of structure, and reduction in failures, as well as improvement in cooling performance.

[0017] Regarding this, a first embodiment and various examples will be described below with reference to the drawings.

[0018] In the drawings, parts having the same or similar configurations and functions are given the same reference numerals, and duplicated explanations are omitted in the following description. Various configurations are shown in the drawings. Each of Figs. 1 to 11, Figs. 13 to 15, and Figs. 17 to 23 is given a right-handed XYZ coordinate system. In this XYZ coordinate system, the direction along the direction in which the light irradiation device 1 emits light (also called the emission direction) is set to the -Z direction, the first direction along the direction opposite to the emission direction is set to the +Z direction, the second direction along the thickness direction of the light irradiation device 1 is set to the +X direction, and the direction along the width direction of the light irradiation device 1 is set to the +Y direction. Here, in the following description, the second direction is set to the +X direction, but the second direction may be set to the -X direction. Note that terms expressing directions such as "upper", "lower", "left", and "right" used in the description of this disclosure are used simply for the purpose of clarifying the description, and are not used for the purpose of limiting the configuration and operation principle of the light irradiation device 1 and the printing device 100.

[0019] <1. First embodiment> <1-1. Configuration of the light irradiation device> The light irradiation device 1 is a device that irradiates light to an object (also called an irradiated object). The light irradiation device 1 of the present disclosure is a type (also called a fanless type) of light irradiation device that does not have a cooling fan (air blowing section) for cooling the light source 11 and the like. Here, the type (fanless type) of light irradiation device that does not have a fan (air blowing section) includes a light irradiation device that does not have a fan (air blowing section) inside the housing 14, a light irradiation device that does not have a fan (air blowing section) that is in contact with the outside of the housing 14, and a light irradiation device that does not have a fan (air blowing section) at the opening of the housing 14. In other words, the fanless type light irradiation device may be a light irradiation device that does not have a fan (air blowing section) inside the housing 14, at a position in contact with the outside of the housing 14, and at the opening of the housing 14. The light irradiation device 1 can irradiate light in a specific wavelength range to an object, for example.

[0020] FIG. 1 is a front view showing the appearance of an example of the light irradiation device 1 according to the first embodiment. FIG. 2 is a left side view showing the appearance of an example of the light irradiation device 1 according to the first embodiment. FIG. 3 is a right side view showing the appearance of an example of the light irradiation device 1 according to the first embodiment. FIG. 4 is a plan view showing the appearance of an example of the light irradiation device 1 according to the first embodiment. FIG. 5 is a bottom view showing the appearance of an example of the light irradiation device 1 according to the first embodiment. FIG. 6 is a perspective view showing the appearance of an example of the light irradiation device 1 according to the first embodiment. FIG. 7 is a perspective view showing the appearance of an example of the light irradiation device 1 according to the first embodiment. FIG. 8 is a cross-sectional view showing an example of a virtual cross section of the light irradiation device 1 viewed in the +Y direction at the position VIII-VIII of FIG. 2 to FIG. 5. FIG. 9 is a left side view showing the appearance of an example of the heat dissipation member 12. FIG. 10 is a front view showing the appearance of an example of the heat dissipation member 12. 1, the positions of the outer edges of the second opening 140b, the third opening 140c, and the light source 11 are typically shown by thin dashed lines which are hidden lines in order to show the respective positions of the second opening 140b, the third opening 140c, and the light source 11. More specifically, in FIG. 1, the positions of the outer edges of the slit hole portion SL1 in the third opening 140c and the substrate 111 and the light emitting element 112 in the light source 11 are typically shown by thin dashed lines which are hidden lines.

[0021] As shown in Fig. 1 to Fig. 8, the light irradiation device 1 includes a light source 11, a heat dissipation member (also called a heat sink) 12, a driving unit 13, and a housing 14. The light source 11 includes a plurality of light emitting elements 112. The heat dissipation member 12 is thermally connected to the light source 11. The driving unit 13 includes a circuit (also called a driving circuit) 132 that drives the light source 11. The housing 14 has a rectangular parallelepiped shape and houses the light source 11, the heat dissipation member 12, and the driving unit 13. In the examples of Fig. 1 to Fig. 8, the light irradiation device 1 includes an optical system 16 and a connector 17.

[0022] <<Case 14>> The housing 14 constitutes the outer shape of the light irradiation device 1. The housing 14 has a rectangular first outer surface 14a, a rectangular second outer surface 14b, a rectangular third outer surface 14c, a rectangular fourth outer surface 14d, a rectangular fifth outer surface 14e, and a rectangular sixth outer surface 14f. The second outer surface 14b is an outer surface on the opposite side of the housing 14 from the first outer surface 14a. The third outer surface 14c is an outer surface that connects the first outer surface 14a and the second outer surface 14b of the housing 14. The fourth outer surface 14d is an outer surface on the opposite side of the housing 14 from the third outer surface 14c. This fourth outer surface 14d connects the first outer surface 14a and the second outer surface 14b. The fifth outer surface 14e is an outer surface that connects the first outer surface 14a and the second outer surface 14b of the housing 14 and also connects the third outer surface 14c and the fourth outer surface 14d. The sixth outer surface 14f is an outer surface of the housing 14 on the opposite side to the fifth outer surface 14e. The sixth outer surface 14f connects the first outer surface 14a and the second outer surface 14b and also connects the third outer surface 14c and the fourth outer surface 14d.

[0023] The first outer surface 14a has, for example, a pair of long sides (also called first long sides) each extending along the +Y direction and a pair of short sides (also called first short sides) each extending along the +X direction. In the examples of Fig. 1 to Fig. 8, the first outer surface 14a faces the -Z direction. From another perspective, the first outer surface 14a is located along a virtual plane parallel to the XY plane.

[0024] The second outer surface 14b has, for example, a pair of long sides (also called second long sides) each extending along the +Y direction and a pair of short sides (also called second short sides) each extending along the +X direction. In the examples of Fig. 1 to Fig. 8, the second outer surface 14b faces the +Z direction. From another perspective, the second outer surface 14b is located along a virtual plane parallel to the XY plane.

[0025] The first outer surface 14a and the second outer surface 14b may have a plane-symmetric relationship with respect to a virtual plane (also called a first symmetry plane) parallel to the XY plane. From another perspective, for example, the length of the first long side and the length of the second long side may be the same, and the length of the first short side and the length of the second short side may be the same.

[0026] The third outer surface 14c has, for example, two sides (also referred to as first sides) that face each other and extend along the +Z direction, and two sides (also referred to as second sides) that face each other and extend along the +Y direction. In the examples of Figs. 1 to 8, the third outer surface 14c faces the -X direction. From another perspective, the third outer surface 14c is located along an imaginary plane parallel to the YZ plane. One of the two second sides that is located on the -Z direction side may be the same as one of the pair of first long sides that is located on the -X direction side, or may be located along this one first long side. One of the two second sides that is located on the +Z direction side may be the same as one of the pair of second long sides that is located on the -X direction side, or may be located along this one second long side.

[0027] The fourth outer surface 14d has, for example, two sides (also called third sides) that face each other and extend along the +Z direction, and two sides (also called fourth sides) that face each other and extend along the +Y direction. In the examples of Figs. 1 to 8, the fourth outer surface 14d faces the +X direction. From another perspective, the fourth outer surface 14d is located along an imaginary plane parallel to the YZ plane. One of the two fourth sides that is located on the -Z direction side may be the same as one of the pair of first long sides that is located on the +X direction side, or may be located along this one first long side. One of the two fourth sides that is located on the +Z direction side may be the same as one of the pair of second long sides that is located on the +X direction side, or may be located along this one second long side.

[0028] The third outer surface 14c and the fourth outer surface 14d may have a plane-symmetrical relationship with respect to a virtual plane (also called a second symmetry plane) parallel to the YZ plane. From another perspective, for example, the length of the first side and the length of the third side may be the same, and the length of the second side and the length of the fourth side may be the same.

[0029] The fifth outer surface 14e has, for example, a pair of long sides (also referred to as third long sides) each extending along the +Z direction and a pair of short sides (also referred to as third short sides) each extending along the +X direction. In the examples of Figs. 1 to 8, the fifth outer surface 14e faces the -Y direction. From another perspective, the fifth outer surface 14e is located along an imaginary plane parallel to the XZ plane. One third long side of the pair of third long sides located on the -X direction side may be the same as one first side of the two first sides located on the -Y direction side, or may be located along this one first side. One third long side of the pair of third long sides located on the +X direction side may be the same as one third side of the two third sides located on the -Y direction side, or may be located along this one third side. The third short side located on the -Z direction side of the pair of third short sides may be the same as the first short side located on the -Y direction side of the pair of first short sides, or may be located along this first short side. The third short side located on the +Z direction side of the pair of third short sides may be the same as the second short side located on the -Y direction side of the pair of second short sides, or may be located along this second short side.

[0030] The sixth outer surface 14f has, for example, a pair of long sides (also referred to as fourth long sides) each extending along the +Z direction and a pair of short sides (also referred to as fourth short sides) each extending along the +X direction. In the examples of Figs. 1 to 8, the sixth outer surface 14f faces the +Y direction. From another perspective, the sixth outer surface 14f is located along an imaginary plane parallel to the XZ plane. One fourth long side of the pair of fourth long sides located on the -X direction side may be the same as one first side of the two first sides located on the +Y direction side, or may be located along this one first side. One fourth long side of the pair of fourth long sides located on the +X direction side may be the same as one third side of the two third sides located on the +Y direction side, or may be located along this one third side. The fourth short side located on the -Z direction side of the pair of fourth short sides may be the same as the first short side located on the +Y direction side of the pair of first short sides, or may be located along this first short side. The fourth short side located on the +Z direction side of the pair of fourth short sides may be the same as the second short side located on the +Y direction side of the pair of second short sides, or may be located along this second short side.

[0031] The fifth outer surface 14e and the sixth outer surface 14f may have a plane-symmetric relationship with respect to a virtual plane (also called a third symmetry plane) parallel to the XZ plane. From another perspective, for example, the third long side and the fourth long side may have the same length, and the third short side and the fourth short side may have the same length.

[0032] Here, the respective lengths (also referred to as first lengths) of the first short side of the first outer surface 14a, the second short side of the second outer surface 14b, the third short side of the fifth outer surface 14e, and the fourth short side of the sixth outer surface 14f correspond to, for example, the thickness of the housing 14. The respective lengths (also referred to as second lengths) of the first long side of the first outer surface 14a, the second long side of the second outer surface 14b, the second side of the third outer surface 14c, and the fourth side of the fourth outer surface 14d correspond to, for example, the width of the housing 14. The respective lengths (also referred to as third lengths) of the first side of the third outer surface 14c, the third side of the fourth outer surface 14d, the third long side of the fifth outer surface 14e, and the fourth long side of the sixth outer surface 14f correspond to, for example, the height of the housing 14.

[0033] The housing 14 has a thin rectangular parallelepiped shape. The dimensions of the housing 14 can be appropriately set according to the specifications and applications of the light irradiation device 1. For example, the first length (corresponding to the thickness of the housing 14) of each of the first short side of the first outer surface 14a, the second short side of the second outer surface 14b, the third short side of the fifth outer surface 14e, and the fourth short side of the sixth outer surface 14f can be set in the range of about 20 millimeters (mm) to 40 mm. For example, the second length (corresponding to the width of the housing 14) of each of the first long side of the first outer surface 14a, the second long side of the second outer surface 14b, the second side of the third outer surface 14c, and the fourth side of the fourth outer surface 14d can be set in the range of about 80 mm to 120 mm. For example, the third lengths (corresponding to the height of housing 14) of the first side of third outer surface 14c, the third side of fourth outer surface 14d, the third long side of fifth outer surface 14e, and the fourth long side of sixth outer surface 14f may be set in the range of about 120 mm to 250 mm. Here, the first length, the second length, and the third length may be set to values ​​different from the above numerical ranges as long as the magnitude relationship of "first length<second length<third length" is satisfied.

[0034] Here, for example, the outer shape of the housing 14 does not need to be a rectangular parallelepiped in a strict sense, and may be a thin rectangular parallelepiped shape. The housing 14 has, for example, eight vertex portions (also called vertex parts) formed by three outer surfaces among the first outer surface 14a, the second outer surface 14b, the third outer surface 14c, the fourth outer surface 14d, the fifth outer surface 14e, and the sixth outer surface 14f. The housing 14 has, for example, twelve side portions (also called side parts) formed by two outer surfaces among the first outer surface 14a, the second outer surface 14b, the third outer surface 14c, the fourth outer surface 14d, the fifth outer surface 14e, and the sixth outer surface 14f. Each of one or more of the eight vertex portions may be a rounded curved surface or a chamfered inclined surface. For example, for the apex, a chamfered inclined surface may be applied that is inclined to any of the three outer surfaces surrounding the apex at an obtuse angle. One or more of the twelve sides may be rounded curved surfaces or chamfered inclined surfaces. For example, for the sides, a chamfered inclined surface may be applied that is inclined to any of the two outer surfaces sandwiching the side at an obtuse angle. Here, for example, the first length may be the distance between the third outer surface 14c and the fourth outer surface 14d, the second length may be the distance between the fifth outer surface 14e and the sixth outer surface 14f, and the third length may be the distance between the first outer surface 14a and the second outer surface 14b.

[0035] From another perspective, the housing 14 includes a first wall portion 141, a second wall portion 142, a third wall portion 143, a fourth wall portion 144, a fifth wall portion 145, and a sixth wall portion 146.

[0036] The first wall portion 141 has the first outer surface 14a of the housing 14. In other words, the first wall portion 141 is a portion of the housing 14 on the first outer surface 14a side. In the examples of Figs. 1 to 8, the first wall portion 141 is a portion of the housing 14 on the -Z direction side. The first wall portion 141 may be, for example, a flat plate-like portion along a virtual surface parallel to the XY plane. The first wall portion 141 is not limited to a flat plate-like portion, and may have, for example, one or more irregularities.

[0037] The second wall portion 142 has the second outer surface 14b of the housing 14. In other words, the second wall portion 142 is a portion of the housing 14 on the second outer surface 14b side. In the examples of Figs. 1 to 8, the second wall portion 142 is a portion of the housing 14 on the +Z direction side. The second wall portion 142 may be, for example, a flat plate-like portion along a virtual surface parallel to the XY plane. The second wall portion 142 is not limited to a flat plate-like portion, and may have, for example, one or more irregularities.

[0038] The third wall portion 143 has a third outer surface 14c of the housing 14. In other words, the third wall portion 143 is a portion of the housing 14 on the third outer surface 14c side. In the example of Figs. 1 to 8, the third wall portion 143 is a portion of the housing 14 on the -X direction side. The third wall portion 143 may be, for example, a flat plate-like portion along a virtual surface parallel to the YZ plane. The third wall portion 143 is not limited to a flat plate-like portion, and may have, for example, one or more irregularities.

[0039] The fourth wall portion 144 has a fourth outer surface 14d of the housing 14. In other words, the fourth wall portion 144 is a portion of the housing 14 on the fourth outer surface 14d side. In the example of Figs. 1 to 8, the fourth wall portion 144 is a portion of the housing 14 on the +X direction side. The fourth wall portion 144 may be, for example, a flat plate-like portion along a virtual surface parallel to the YZ plane. The fourth wall portion 144 is not limited to a flat plate-like portion, and may have, for example, one or more irregularities.

[0040] The fifth wall portion 145 has a fifth outer surface 14e of the housing 14. In other words, the fifth wall portion 145 is a portion of the housing 14 on the fifth outer surface 14e side. In the example of Figs. 1 to 8, the fifth wall portion 145 is a portion of the housing 14 on the -Y direction side. The fifth wall portion 145 may be, for example, a flat plate-like portion along a virtual surface parallel to the XZ plane. The fifth wall portion 145 is not limited to a flat plate-like portion, and may have, for example, one or more irregularities.

[0041] The sixth wall portion 146 has a sixth outer surface 14f of the housing 14. In other words, the sixth wall portion 146 is a portion of the housing 14 on the sixth outer surface 14f side. In the example of Figs. 1 to 8, the sixth wall portion 146 is a portion of the housing 14 on the +Y direction side. The sixth wall portion 146 may be, for example, a flat plate-like portion along a virtual surface parallel to the XZ plane. The sixth wall portion 146 is not limited to a flat plate-like portion, and may have, for example, one or more irregularities.

[0042] The housing 14 has an internal space (also referred to as an internal space) 14i surrounded by, for example, a first wall portion 141, a second wall portion 142, a third wall portion 143, a fourth wall portion 144, a fifth wall portion 145, and a sixth wall portion 146. In other words, the first wall portion 141 is located on the -Z direction side of the internal space 14i. The second wall portion 142 is located on the +Z direction side of the internal space 14i. The third wall portion 143 is located on the -X direction side of the internal space 14i. The fourth wall portion 144 is located on the +X direction side of the internal space 14i. The fifth wall portion 145 is located on the -Y direction side of the internal space 14i. The sixth wall portion 146 is located on the +Y direction side of the internal space 14i.

[0043] The housing 14 has a first opening 140a, a second opening 140b, and a third opening 140c.

[0044] The first opening 140a is open at least on the first outer surface 14a. The first opening 140a is an opening (also called an irradiation port) for passing light from the light source 11. In the first embodiment, the first opening 140a penetrates the first wall portion 141 in the thickness direction of the first wall portion 141.

[0045] In the examples of FIG. 1 to FIG. 8, the first opening 140a is an elongated opening located along the +Y direction. When viewed in a plan view in the +Z direction, the first opening 140a is an elongated rectangular opening having a longitudinal direction along the +Y direction. More specifically, the first opening 140a is open in a region from the end of the fifth outer surface 14e in the -Z direction to the end of the sixth outer surface 14f in the -Z direction via the first outer surface 14a. From another perspective, the first opening 140a penetrates the first wall portion 141 in the -Z direction. More specifically, the first opening 140a penetrates the housing 14 in a region from the end of the fifth wall portion 145 in the -Z direction to the end of the sixth wall portion 146 in the -Z direction via the first wall portion 141.

[0046] Here, the length of the first opening 140a in the thickness direction (also referred to as the thickness direction) of the housing 14 may be, for example, about 20% to 70% of the first length corresponding to the thickness of the housing 14. For example, if the first length of the housing 14 is about 30 mm, the length of the first opening 140a in the thickness direction of the housing 14 may be about 8 mm. In the example of FIG. 1 to FIG. 8, the thickness direction of the housing 14 is a direction along the +X direction as the second direction. The length of the first opening 140a in the width direction (also referred to as the width direction) of the housing 14 may be, for example, about the same as the second length corresponding to the width of the housing 14. For example, if the second length of the housing 14 is about 120 mm, the length of the first opening 140a in the width direction of the housing 14 may be about 120 mm. In the example of FIG. 1 to FIG. 8, the width direction of the housing 14 is a direction along the +Y direction. If the first opening 140a is open over the entire first outer surface 14a in the width direction of the housing 14, the light irradiation device 1 can be made smaller. In this case, for example, when a plurality of light irradiation devices 1 are arranged in the width direction of the light irradiation device 1 and used, the distribution of the amount of light emitted from the plurality of light irradiation devices 1 can be made more uniform in the width direction of the light irradiation device 1. However, the length of the first opening 140a in the width direction of the housing 14 is not limited to a length approximately equal to the second length corresponding to the width of the housing 14. The shape of the first opening 140a may be an elongated rectangular shape like the first outer surface 14a, but is not limited thereto. For example, the shape of the first opening 140a may be appropriately set according to the shape of the area of ​​the object (object to be irradiated) to which the light irradiation device 1 irradiates light. The shape of the first opening 140a may be, for example, a long and narrow wavy shape in the width direction of the housing 14, a long and narrow oval shape in the width direction of the housing 14, or a shape in which a plurality of circular portions are arranged in the width direction of the housing 14. The size of the first opening 140a when the first outer surface 14a is viewed in plan may be appropriately set within the range of the size of the first outer surface 14a according to the size of the area of ​​the object (object to be irradiated) to which light is irradiated by the light irradiation device 1. The first opening 140a may be open at the center of the first outer surface 14a including the center point of the first outer surface 14a, or may be open at a position of the first outer surface 14a shifted from the center point of the first outer surface 14a.

[0047] The second opening 140b is open in a region of the third outer surface 14c on the first outer surface 14a side. Here, for example, assume that the third outer surface 14c is virtually divided equally into N1 regions (N1 is a natural number of 2 or more) in the +Z direction as the first direction. In this case, the region of the third outer surface 14c on the first outer surface 14a side may be included in the region located closest to the first outer surface 14a side among the N1 regions. The natural number N1 may be appropriately set according to the design of the intake and exhaust and heat dissipation in the light irradiation device 1. The natural number N1 may be, for example, 2, 3, or 4.

[0048] The second opening 140b connects the internal space 14i of the housing 14 to the space (also referred to as the external space) 14o outside the housing 14. The second opening 140b, for example, serves as an opening (also referred to as an air intake) for drawing air from the external space 14o of the housing 14 to the internal space 14i. In the first embodiment, the second opening 140b penetrates the third wall portion 143 in the thickness direction of the third wall portion 143. The housing 14 has, for example, an end face (also referred to as a first end face) 143e that constitutes the edge of the second opening 140b on the first outer surface 14a side. More specifically, for example, the third wall portion 143 has a first end face 143e that constitutes the edge of the second opening 140b on the first outer surface 14a side.

[0049] In the examples of FIG. 1 to FIG. 8, the second opening 140b is a rectangular opening. More specifically, the second opening 140b is a rectangular opening having a pair of long sides (also called the fifth long sides) along the +Y direction and a pair of short sides (also called the fifth short sides) along the +Z direction. From another perspective, the second opening 140b penetrates the third wall portion 143 in the +X direction. The length of the fifth long side of the second opening 140b may be equal to or less than the length of the first long side in the width direction of the housing 14. The length of the fifth short side of the second opening 140b may be appropriately set according to the dimensions of the heat dissipation member 12 and the design of the intake and exhaust and heat dissipation in the light irradiation device 1.

[0050] The third opening 140c is open in a region extending from the second outer surface 14b to the portion of the third outer surface 14c on the second outer surface 14b side. Here, for example, assume that the third outer surface 14c is virtually divided equally into N2 portions (N2 is a natural number of 4 or more) in the +Z direction as the first direction. In this case, the portion of the third outer surface 14c on the second outer surface 14b side may be included in the portion located closest to the second outer surface 14b side among the N2 portions. The natural number N2 may be appropriately set according to the design of the intake and exhaust and heat dissipation in the light irradiation device 1. The natural number N2 may be, for example, 4, 5, 6, 7, 8, 9, or 10.

[0051] The third opening 140c connects the internal space 14i of the housing 14 to the external space 14o of the housing 14. The third opening 140c, for example, serves as an opening (also called an exhaust port) for discharging air from the internal space 14i of the housing 14 to the external space 14o.

[0052] Here, the third opening 140c may have a plurality of holes each opening in a region extending from the second outer surface 14b to the portion of the third outer surface 14c on the second outer surface 14b side. In the example of FIG. 1 to FIG. 8, the plurality of holes are a plurality of slit-shaped holes (also called slit hole portions) SL1. Each slit hole portion SL1 opens in a region extending from the second outer surface 14b to the portion of the third outer surface 14c on the second outer surface 14b side. From another perspective, each slit hole portion SL1 penetrates the second wall portion 142 and the third wall portion 143 in the portion extending from the second wall portion 142 to the third wall portion 143. In other words, the portion extending from the second wall portion 142 to the third wall portion 143 has a plurality of slit hole portions SL1 for discharging air from the internal space 14i of the housing 14 to the external space 14o. In this case, the plurality of slit hole portions SL1 serve as an exhaust port.

[0053] A first predetermined number of slit holes SL1 is applied to the plurality of slit holes SL1. The first predetermined number is 2 or more. In other words, two or more slit holes SL1 are applied to the plurality of slit holes SL1. The plurality of slit holes SL1 may be arranged in the width direction of the housing 14 from the fifth outer surface 14e to the sixth outer surface 14f, for example. The plurality of slit holes SL1 may be arranged in the width direction of the housing 14 at a first pitch, for example. Each of the plurality of slit holes SL1 has a shape in which a first elongated portion that opens at the second outer surface 14b and runs along the thickness direction of the housing 14 from the fourth outer surface 14d to the third outer surface 14c, and a second elongated portion that opens at the third outer surface 14c and runs along the height direction of the housing 14 from the second outer surface 14b to the first outer surface 14a are connected in an L-shape. In this way, for example, if the third opening 140c is configured with a plurality of slit hole portions SL1, the intrusion of foreign matter from the external space 14o of the housing 14 to the internal space 14i can be reduced. The foreign matter can include, for example, dust, dirt, metal parts, tools, etc. Here, the plurality of holes in the third opening 140c may be, for example, a plurality of holes arranged in a mesh pattern.

[0054] In the examples of Fig. 2, Fig. 4, and Fig. 6 to Fig. 8, a first predetermined number of slit hole portions SL1 are arranged in the +Y direction along the width direction of the housing 14. Each slit hole portion SL1 has a first elongated portion that opens on the second outer surface 14b and extends along the -X direction, and a second elongated portion that opens on the third outer surface 14c and extends along the -Z direction, which are connected in an L-shape. The first predetermined number and the first pitch of the multiple slit hole portions SL1, as well as the width and length of each slit hole portion SL1, may be appropriately set depending on, for example, the design of the intake and exhaust and heat dissipation in the light irradiation device 1 and the design of the appearance.

[0055] The first predetermined number may be, for example, about 28. In other words, the number of slit holes SL1 may be about 28. The first pitch may be, for example, about 4 mm. The width of each of the slit holes SL1 may be about 2 mm. The length of the first elongated portion in the -X direction of each slit hole SL1 (also called the fourth length) may be, for example, about 5 mm. The length of the second elongated portion in the -Z direction of each slit hole SL1 (also called the fifth length) may be, for example, about 15 mm. The first predetermined number is not limited to 28, and may be another number, for example, about 20 to 40. In other words, the number of slit holes SL1 other than 28, such as about 20 to 40, may be applied to the multiple slit holes SL1. The first pitch is not limited to about 4 mm, and may be set to another length, for example, about 2 mm to 6 mm, depending on the first predetermined number. The length (fourth length) of the first elongated portion of each slit hole portion SL1 in the -X direction is not limited to about 5 mm, and may be set to another length, for example, about 3 mm to 10 mm, depending on the thickness of the housing 14 and the position of the connector 17. The length (fifth length) of the second elongated portion of each slit hole portion SL1 in the -Z direction is not limited to about 15 mm, and may be set to another length, for example, about 10 mm to 20 mm, depending on the size of the housing 14. The width of the slit hole portion SL1, the length of the first elongated portion (fourth length), and the length of the second elongated portion (fifth length) may be the same or different among the multiple slit hole portions SL1.

[0056] The arrangement, shape, size, and the like of the second opening 140b and the third opening 140c in the housing 14 may be appropriately set according to the design of the intake and exhaust and heat dissipation in the light irradiation device 1, and the like.

[0057] The housing 14 may be made of a material such as metal, eg, aluminum, or plastic.

[0058] The housing 14 may be formed by, for example, connecting a plurality of members to each other. The plurality of members may be connected via the heat dissipation member 12 by being fixed to the heat dissipation member 12, or may be directly connected. The plurality of members constituting the housing 14 may include, for example, a first member, a second member, and a third member. The first member may include, for example, a member including the first wall portion 141 and the portions of the third wall portion 143, the fourth wall portion 144, the fifth wall portion 145, and the sixth wall portion 146 that are closer to the first wall portion 141 than the heat dissipation member 12. The second member may include, for example, a member including the portions of the fourth wall portion 144, the fifth wall portion 145, and the sixth wall portion 146 that extend from a region along the heat dissipation member 12 to a region along the second wall portion 142. The third member may be, for example, a member including the second wall portion 142 and a portion of the third wall portion 143 that extends from the area along the heat dissipation member 12 to the area along the second wall portion 142.

[0059] The fixing of the multiple members to the heat dissipation member 12 can be achieved, for example, by fastening using screws or the like. The fixing of the multiple members to the heat dissipation member 12 is not limited to fastening using screws or the like, and may be achieved in other forms such as adhesion, bonding, caulking, and fitting. In addition, direct connection between the multiple members may be achieved in various forms such as fastening using screws or the like, adhesion, bonding, caulking, and fitting.

[0060] Each of the first member, the second member, and the third member may have, for example, a portion (also referred to as a connecting portion) for connecting them to each other. For example, the third member may include a plate-shaped first connecting portion that protrudes from a first side of the third wall portion 143 on the fifth wall portion 145 side along a part of the fifth wall portion 145, and a plate-shaped second connecting portion that protrudes from a first side of the third wall portion 143 on the sixth wall portion 146 side along a part of the sixth wall portion 146. In this case, for example, the first connecting portion and the fifth wall portion 145 are fastened by screws or the like, and the second connecting portion and the sixth wall portion 146 are fastened by screws or the like, so that the second member and the third member can be connected to each other. The first member may be manufactured, for example, by metal casting or resin molding. Each of the second member and the third member may be manufactured by, for example, performing various processes on a metal plate-shaped member, or by molding a resin. The various processes may include, for example, one or more processes among press molding, bending, punching, cutting, and the like.

[0061] <<Heat dissipation member 12>> The heat dissipation member 12 is a member for dissipating heat generated in association with light emission in the light source 11. The heat dissipation member 12 is thermally connected to the light source 11. The material of the heat dissipation member 12 is, for example, a metal having excellent thermal conductivity, such as aluminum or copper. The form in which the heat dissipation member 12 is thermally connected to the light source 11 may include not only a form in which the heat dissipation member 12 is directly connected to the light source 11, but also a form in which the heat dissipation member 12 is indirectly connected to the light source 11 via one or more members having excellent thermal conductivity.

[0062] The heat dissipation member 12 includes a base portion 121 and a plurality of protrusions 122 .

[0063] The base portion 121 is located in a region on the first outer surface 14a side of the internal space 14i of the housing 14. For example, assume that the internal space 14i is virtually divided equally into N3 regions (N3 is a natural number equal to or greater than 4) in the +Z direction as the first direction. In this case, the region on the first outer surface 14a side of the internal space 14i of the housing 14 may be included in the region located closest to the first outer surface 14a side among the N3 regions. The natural number N3 may be appropriately set according to the design of heat dissipation and intake and exhaust in the light irradiation device 1. The natural number N3 may be, for example, 4, 5, or 6. The base portion 121 may have, for example, a block shape or a plate shape.

[0064] The base portion 121 may be in contact with, for example, the inner surface of the housing 14. In this case, for example, the third wall portion 143 may be fixed to the base portion 121, the fourth wall portion 144 may be fixed, the fifth wall portion 145 may be fixed, or the sixth wall portion 146 may be fixed. The third wall portion 143 has, for example, a surface (also referred to as a first inner surface) Iw1 on the side of the internal space 14i. The fourth wall portion 144 has, for example, a surface (also referred to as a second inner surface) Iw2 on the side of the internal space 14i. Here, for example, the base portion 121 may be in contact with the first inner surface Iw1 of the third wall portion 143, or may be in contact with the second inner surface Iw2 of the fourth wall portion 144. In other words, the base portion 121 may be in contact with, for example, the first inner surface Iw1 as an inner surface located on the third outer surface 14c side of the internal space 14i of the housing 14, or may be in contact with the second inner surface Iw2 as an inner surface located on the fourth outer surface 14d side of the internal space 14i of the housing 14. The fifth wall portion 145 has, for example, a surface on the internal space 14i side (also referred to as a third inner surface). The sixth wall portion 146 has, for example, a surface on the internal space 14i side (also referred to as a fourth inner surface). Here, for example, the base portion 121 may be in contact with the third inner surface of the fifth wall portion 145, or may be in contact with the fourth surface of the sixth wall portion 146. In other words, the base portion 121 may be in contact with, for example, a third inner surface which is an inner surface located on the fifth outer surface 14e side of the internal space 14i of the housing 14, or may be in contact with a fourth inner surface which is an inner surface located on the sixth outer surface 14f side of the internal space 14i of the housing 14.

[0065] The base portion 121 may be close to the inner surface of the housing 14, for example. In this case, the base portion 121 and the inner surface of the housing 14 may be adhered to each other by interposing thermal grease, which is called heat-conducting grease or heat-dissipating grease, for example. Here, for example, the base portion 121 may be close to the first inner surface Iw1 of the third wall portion 143, or close to the second inner surface Iw2 of the fourth wall portion 144. Also, for example, the base portion 121 may be close to the third inner surface of the fifth wall portion 145, or close to the fourth inner surface of the sixth wall portion 146.

[0066] In the examples of Figs. 8 to 10, the base portion 121 has a rectangular parallelepiped shape having an outer surface along a virtual plane parallel to the first outer surface 14a and the second outer surface 14b. More specifically, the base portion 121 may have a rectangular parallelepiped shape along a virtual plane parallel to the XY plane. The base portion 121 may have a surface (also referred to as a first surface) 121u located on the second outer surface 14b side and facing the second outer surface 14b side. The first surface 121u may be, for example, a surface facing the +Z direction. In other words, the first surface 121u may be a surface along a virtual plane parallel to the XY plane. The first surface 121u may be flush with the first end surface 143e constituting the edge of the second opening 140b of the housing 14 on the first outer surface 14a side, or may be slightly offset from the first end surface 143e toward the first outer surface 14a side or the second outer surface 14b side. From another perspective, most or all of the base portion 121 may be located closer to the first outer surface 14a than the second opening 140b. The base portion 121 has a surface (also referred to as a second surface) 121b located on the first outer surface 14a side. The second surface 121b may be, for example, a surface facing the -Z direction. In other words, the second surface 121b may be a surface along a virtual surface parallel to the XY plane.

[0067] Each of the multiple protrusions 122 protrudes from the base portion 121 toward the second outer surface 14b along a first direction from the first outer surface 14a toward the second outer surface 14b. A plurality of gaps 12s are present between the multiple protrusions 122. The multiple gaps 12s between the multiple protrusions 122 are adjacent to the second opening 140b. In other words, the multiple gaps 12s are connected to the external space 14o via the second opening 140b. This allows air to flow from the external space 14o of the housing 14 into the multiple gaps 12s via the second opening 140b.

[0068] Each of the plurality of protrusions 122 may have, for example, a thin plate-like shape. According to the heat dissipation member 12, air flows through the plurality of gaps 12s between the plurality of protrusions 122, so that heat transferred from the light source 11 to the heat dissipation member 12 is dissipated into the air, and the light source 11 can be cooled. A second predetermined number of protrusions 122 is applied to the plurality of protrusions 122. The second predetermined number is two or more. In other words, two or more protrusions 122 are applied to the plurality of protrusions 122. The plurality of protrusions 122 may be arranged, for example, in the width direction of the housing 14 from the fifth outer surface 14e to the sixth outer surface 14f. The plurality of protrusions 122 may be arranged, for example, at a second pitch in the width direction of the housing 14. Each of the plurality of protrusions 122 may be, for example, a thin plate-like portion (also called a fin) along a virtual plane parallel to the fifth outer surface 14e. Each of the multiple protrusions 122 may have a thickness in the width direction of the housing 14 from the fifth outer surface 14e to the sixth outer surface 14f. Each of the multiple protrusions 122 may have a predetermined length (also referred to as a sixth length) in the first direction from the first outer surface 14a to the second outer surface 14b, for example.

[0069] In the examples of FIG. 2 and FIG. 6 to FIG. 10, each of the second predetermined number of protrusions 122 protrudes from the first surface 121u of the base portion 121 toward the +Z direction as the first direction. Each of the second predetermined number of protrusions 122 is a thin plate-like portion (fin) along a virtual surface parallel to the XZ plane, and has a thickness along the +Y direction as the width direction of the housing 14. Each of the second predetermined number of protrusions 122 has a predetermined length (sixth length) in the +Z direction as the first direction. The multiple protrusions 122 are arranged at a second pitch in the +Y direction as the width direction of the housing 14. The second predetermined number and the second pitch of the multiple protrusions 122, as well as the thickness and the sixth length of each protrusion 122, can be appropriately set according to, for example, the design of the intake and exhaust and heat dissipation in the light irradiation device 1.

[0070] The second predetermined number may be, for example, about 19. In other words, 19 protrusions 122 may be applied to the plurality of protrusions 122. The second pitch may be, for example, about 6 mm. The thickness of each of the plurality of protrusions 122 may be, for example, about 2 mm. The sixth length of each of the plurality of protrusions 122 may be, for example, about 28 mm. The second predetermined number is not limited to 19, and may be another number, for example, about 10 to 30. In other words, a number of protrusions 122 other than 19, such as about 10 to 30, may be applied to the plurality of protrusions 122. The second pitch is not limited to 6 mm, and may be another length, for example, about 4 mm to 11 mm, depending on the second predetermined number. The thickness of the protrusions 122 is not limited to 2 mm, and may be another thickness, for example, about 1 mm to 4 mm. The sixth length of the protrusion 122 is not limited to 28 mm, and may be another length, for example, about 20 mm to 40 mm. The thickness and the sixth length of the protrusion 122 may be the same or different among the multiple protrusions 122.

[0071] Two adjacent protrusions 122 among the multiple protrusions 122 are located with a gap 12s therebetween. Here, for example, if all of the multiple gaps 12s are connected to the external space 14o via the second opening 140b, the amount of air flowing from the external space 14o to the multiple gaps 12s via the second opening 140b per unit time can be increased. In the example of FIG. 2 and FIG. 6 to FIG. 10, if the multiple protrusions 122 are 19 fins, 18 gaps 12s exist between the 19 fins. And, for example, if all of the 18 gaps 12s as the multiple gaps 12s are connected to the external space 14o via the second opening 140b, the amount of air flowing from the external space 14o to the multiple gaps 12s via the second opening 140b per unit time can be increased.

[0072] The heat dissipation member 12 may have a structure in which, for example, a rectangular metal block is provided with a large number of grooves formed therein by cutting or the like to increase the surface area, or may have a structure in which a number of thin metal plates are attached to a metal block or plate.

[0073] <<Light source 11>> The light source 11 is located on the first outer surface 14a side of the base portion 121 of the heat dissipation member 12. The light source 11 faces a first opening 140a that opens in the first outer surface 14a. The light source 11 has, for example, a substrate 111 and a plurality of light-emitting elements 112. In the example of FIG. 5, the light source 11 has three substrates 111 and 18 light-emitting elements 112. The plurality of light-emitting elements 112 are disposed on the substrate 111.

[0074] The substrate 111 is a substrate on which a plurality of light-emitting elements 112 are arranged (also referred to as a substrate for arranging light-emitting elements). For example, a ceramic plate-shaped substrate (also referred to as a ceramic wiring substrate) is used for the substrate 111. On the surface and inside of the substrate 111, there are wiring conductors that electrically connect the inside and outside of the substrate 111. For example, a conductive material such as tungsten, molybdenum, manganese, or copper is used as the material for the wiring conductor. If the substrate 111 is a ceramic wiring substrate, the base material of the ceramic wiring substrate is ceramics having insulating properties. Therefore, the ceramic wiring substrate has heat resistance against heat generated by the light source 11 on which a plurality of light-emitting elements 112 are integrated.

[0075] The substrate 111 is located on the first outer surface 14a side of the base portion 121 of the heat dissipation member 12. The substrate 111 has, for example, a plate-like shape along the base portion 121. The substrate 111 may be fixed to the base portion 121, for example. The substrate 111 may be fixed to the base portion 121 by, for example, screwing. The base portion 121 and the substrate 111 may be brought into close contact with each other by interposing thermal grease between them. This may improve the thermal connection between the light source 11 and the heat dissipation member 12. As a result, the efficiency of heat dissipation from the light source 11 through the heat dissipation member 12 may be improved. Here, the substrate 111 may be fixed to the base portion 121 via, for example, a metal member having excellent thermal conductivity.

[0076] For example, a light emitting diode (LED) element is applied to each of the plurality of light emitting elements 112. The type of the light emitting elements 112 can be appropriately selected according to the wavelength of light emitted from the light emitting elements 112. For example, a gallium nitride (GaN) based LED may be applied as an LED that emits ultraviolet light, and a gallium arsenide (GaAs) based LED may be applied as an LED that emits infrared light. For example, the plurality of light emitting elements 112 may be arranged in a single row on the substrate 111, or may be arranged in a matrix having multiple rows.

[0077] In the example of Fig. 5, the substrate 111 has a flat plate shape along a virtual surface parallel to the XY plane. The substrate 111 is fixed on the second surface 121b of the base portion 121. The three substrates 111 are arranged adjacent to each other along the +Y direction. On the three substrates 111, 18 light-emitting elements 112 are arranged in a row along the +Y direction. More specifically, six light-emitting elements 112 are arranged in a row along the +Y direction on the surface of each of the three substrates 111 facing the -Z direction.

[0078] <<Drive unit 13>> The drive unit 13 is located in the internal space 14i of the housing 14, between the multiple protrusions 122 and the second outer surface 14b.

[0079] The driving unit 13 is electrically connected to the light source 11. The driving unit 13 includes, for example, a wiring board 131 and a driving circuit 132.

[0080] For example, a printed circuit board or the like is applied to the wiring board 131. For example, the wiring board 131 is fixed to the inner surface side of the housing 14. Here, for example, the wiring board 131 may be fixed to the inner surface side of the housing 14 by screwing or the like via a pedestal, a support, or a spacer arranged on the inner surface of the housing 14. Also, for example, the wiring board 131 may be fixed to the inner surface side of the housing 14 by fitting the wiring board 131 into unevenness arranged on the inner surface of the housing 14. In the example of FIG. 8, the wiring board 131 is fixed to the inner surface side of the second wall portion 142 of the housing 14. For example, the wiring board 131 may be a flat board located along a virtual plane parallel to the YZ plane.

[0081] The driving circuit 132 includes, for example, one or more electronic components 132i. In FIG. 8, the region in which the one or more electronic components 132i are located is shown as a long and narrow rectangle using diagonal hatching from top to bottom. The one or more electronic components 132i are attached to the wiring board 131. The driving circuit 132 can, for example, supply power to the light source 11 and control the light emission of the light source 11. The driving unit 13 having the driving circuit 132 generates heat when driving the light source 11. For this reason, it is required to cool the driving unit 13 by appropriate heat dissipation. When the one or more electronic components 132i include a plurality of electronic components 132i, if the plurality of electronic components 132i are arranged in a form in which they are not densely packed, the rise in temperature in the driving circuit 132 can be reduced.

[0082] Here, for example, when one or more electronic components 132i include electronic components such as power transistors that tend to generate a large amount of heat, a heat sink may be attached to the driving unit 13 in order to increase the amount of heat dissipated from the electronic components 132i. In order to effectively direct the air flow to the parts of the driving unit 13 that tend to become hot, one or more structures such as grooves, fins, and air guide plates may be located on the inner surface of the housing 14 around the driving unit 13.

[0083] The driving circuit 132 and the light source 11 may be electrically connected by various wiring members. More specifically, the driving circuit 132 and the plurality of light emitting elements 112 may be electrically connected via various wiring members and the substrate 111. For example, a flexible printed circuit (FPC) may be applied to the various wiring members. The FPC may be connected to the driving circuit 132 via a board connector. The position, shape, size, and the like of the various wiring members electrically connecting the driving circuit 132 and the light source 11 may be appropriately set according to the design of an appropriate air flow in the internal space 14i of the housing 14. For example, if the various wiring members are arranged between the heat dissipation member 12 and the second wall portion 142 and in a form that does not pass through the space between the driving unit 13 and the third wall portion 143 as much as possible, the decrease in the speed and amount of the air flow from the plurality of gaps 12s of the heat dissipation member 12 toward the third opening 140c may be reduced. This may reduce the decrease in the efficiency of heat dissipation from the heat dissipation member 12. Here, a configuration can be adopted in which various wiring components pass from the substrate 111 between the heat dissipation member 12 and the inner surface of the housing 14, and then pass through a location a short distance from the heat dissipation member 12 to connect to the drive circuit 132.

[0084] <<Optical system 16>> The optical system 16 can adjust the optical path of the light emitted from the light source 11. The optical system 16 is located, for example, between the light source 11 and the first opening 140a or at the first opening 140a. The shape and size of the optical system 16 can be appropriately set according to the size and shape of the area of ​​the object (object to be irradiated) to be irradiated with light, and the specifications of the intensity of the light irradiated to the object (object to be irradiated). For example, various lenses are applied to the optical system 16. In the examples of Figs. 1, 5, 6, and 8, a cylindrical rod lens having a central axis along the +Y direction is adopted as the optical system 16. For example, various optical members such as a semi-cylindrical cylindrical lens or a flat transparent member different from a rod lens may be applied to the optical system 16. For example, transparent glass or a heat-resistant plastic is applied as the material of the optical system 16. For example, the optical system 16 may include a reflecting portion that reflects light.

[0085] <<Connector 17>> The connector 17 is a part that connects a plurality of wires connected to the driving unit 13 and a plurality of wires located outside the housing 14. The connector 17 is located, for example, on the second outer surface 14b side of the light irradiation device 1. The light irradiation device 1 may have one connector 17, or may have two or more connectors 17. In the example of FIG. 1 to FIG. 8, the light irradiation device 1 has two connectors 17. The plurality of wires include, for example, a wire (also called a power line) that supplies power from the outside to the driving unit 13, and a wire (also called a signal line) that receives a signal from the outside to the driving unit 13 and transmits a signal from the driving unit 13 to the outside. Through this connector 17, the supply of power from the outside of the light irradiation device 1 to the driving unit 13 and the exchange of control signals can be realized.

[0086] <1-1-1. Air flow inside the case> Fig. 11 is a cross-sectional view showing a schematic path of air flow in an example of the light irradiation device 1 according to the first embodiment. The cross-sectional view of Fig. 11 corresponds to the cross-sectional view of Fig. 8. In Fig. 11, the light irradiation device 1 is arranged with the first outer surface 14a facing downward, and the path of air flow generated when the light source 11 generates heat by light emission is shown by two curved lines and arrows drawn with two-dot chain lines. In Fig. 11, the state in which light is emitted from the light emitting element 112 is shown by a downward arrow drawn with a thin dashed line.

[0087] Here, for example, with the first outer surface 14a facing downward, heat generated in response to the light emission of the multiple light emitting elements 112 is dissipated to the internal space 14i of the housing 14 via the heat dissipation member 12. In this case, air that flows from the external space 14o into the multiple gaps 12s between the multiple protrusions 122 via the second opening 140b is warmed by the heat dissipated from the multiple protrusions 122 and rises, generating a smooth air flow that is discharged to the external space 14o via the third opening 140c. At this time, due to the chimney effect, the air passes from the external space 14o through the second opening 140b, the internal space 14i, and the third opening 140c in this order and is discharged to the external space 14o. This air flow can cool the heat dissipation member 12.

[0088] In the first embodiment, when the first outer surface 14a is arranged facing downward, the third opening 140c is located from the upward second outer surface 14b to the upper part of the third outer surface 14c. Therefore, for example, even if the connector 17 or the like is present on the second outer surface 14b side, the size of the opening required for exhausting from the internal space 14i to the external space 14o is secured in the third opening 140c, and the distance between the multiple protrusions 122 and the third opening 140c can be long. As a result, a smooth upward air current is generated from the multiple gaps 12s between the multiple protrusions 122 toward the third opening 140c, and the speed of the upward air current can be increased by the chimney effect. As a result, the heat dissipation member 12 can be efficiently cooled. Therefore, the heat dissipation member 12 can be efficiently cooled without providing a cooling fan in the light irradiation device 1. Therefore, the light irradiation device 1 can be made compact, the structure can be simplified, and the number of failures can be reduced, while the cooling performance can be improved.

[0089] Here, for example, the driving unit 13 may be located in a region of the internal space 14i closer to the fourth outer surface 14d than to the third outer surface 14c. In other words, for example, the driving unit 13 may be located in a region of the internal space 14i closer to the fourth wall portion 144 than to the third wall portion 143. This can reduce a decrease in the speed and flow rate of the air flow from the multiple gaps 12s of the heat dissipation member 12 toward the third opening 140c. Furthermore, for example, one or more electronic components 132i may be located between the second opening 140b and the third opening 140c in the first direction from the first outer surface 14a toward the second outer surface 14b. And, for example, the driving unit 13 may be located with one or more electronic components 132i facing the third outer surface 14c side. In other words, for example, the driving unit 13 may be located with one or more electronic components 132i facing the third wall portion 143 side. From another perspective, for example, the surface of wiring board 131 on which one or more electronic components 132i are mounted may face the third wall portion 143. In the examples of Fig. 8 and Fig. 11, the surface of wiring board 131 on which one or more electronic components 132i are mounted may face the -X direction.

[0090] If this configuration is adopted, in the case where the first outer surface 14a is arranged facing downward, when heat generated in response to light emission from the plurality of light-emitting elements 112 is dissipated into the internal space 14i of the housing 14 via the heat dissipation member 12, the path of the air flow rising from the plurality of gaps 12s toward the third opening 140c may include a path along one or more electronic components 132i. This increases the flow of air hitting the one or more electronic components 132i, and the efficiency of cooling the drive circuit 132 may be improved. As a result, the stability of the operation of the drive circuit 132 may be improved, and the reliability of the light irradiation device 1 may be improved.

[0091] Here, for example, if the base portion 121 of the heat dissipation member 12 is in contact with the inner surface of the housing 14, the efficiency of cooling the heat dissipation member 12 can be improved by heat transfer from the heat dissipation member 12 to the housing 14.

[0092] Here, for example, the portion of the plurality of gaps 12s on the base portion 121 side may be adjacent to the second opening 140b, and the length of the second opening 140b may be equal to or less than the length of the plurality of protrusions 122 in the first direction from the first outer surface 14a to the second outer surface 14b. If this configuration is adopted, when the first outer surface 14a is arranged facing downward, when heat generated in response to the light emission of the plurality of light-emitting elements 112 is dissipated to the internal space 14i of the housing 14 via the heat dissipation member 12, the air flowing from the external space 14o to the internal space 14i of the housing 14 via the second opening 140b may pass through a wider area of ​​the plurality of gaps 12s. In addition, the distance between the second opening 140b and the third opening 140c may be increased. This may increase the speed of the rising air current due to the chimney effect from the plurality of gaps 12s between the plurality of protrusions 122 to the third opening 140c. As a result, the heat dissipation member 12 may be efficiently cooled. Here, the size of the portions of the plurality of gaps 12s on the base portion 121 side can be set appropriately according to the dimensions, intake / exhaust, and heat dissipation design, etc., of the light irradiation device 1. The portions of the plurality of gaps 12s on the base portion 121 side may include, for example, a region of the plurality of gaps 12s that is in contact with the first surface 121u of the base portion 121, or a region of the plurality of gaps 12s that is close to the first surface 121u of the base portion 121.

[0093] Here, for example, the portion of the plurality of protrusions 122 on the second outer surface 14b side may be in contact with the first inner surface Iw1 located on the third outer surface 14c side of the internal space 14i of the housing 14. If this configuration is adopted, the heat dissipation member 12 can be cooled more efficiently by heat transfer from the plurality of protrusions 122 to the housing 14. Here, the size of the portion of the plurality of protrusions 122 on the second outer surface 14b side can be appropriately set according to the design of the dimensions, intake and exhaust, heat dissipation, etc. of the light irradiation device 1. Here, for example, a case is assumed in which the plurality of protrusions 122 are virtually equally divided into N4 regions (N4 is a natural number of 2 or more) in the +Z direction as the first direction. In this case, the portion of the plurality of protrusions 122 on the second outer surface 14b side may be included in the region located closest to the second outer surface 14b side among the N4 regions. The natural number N4 can be appropriately set according to the design of the intake and exhaust, heat dissipation, etc. of the light irradiation device 1. The natural number N4 may be, for example, 2, 3, 4, or any other natural number equal to or greater than 5.

[0094] Here, it is assumed that the length of the second opening 140b in the first direction is equal to or less than the length of the protrusion 122, and the portion of the plurality of protrusions 122 on the second outer surface 14b side is in contact with the first inner surface Iw1. In this case, the plurality of slit-shaped portions of the plurality of gaps 12s in contact with the second opening 140b function as a substantial air intake port that draws air from the external space 14o to the internal space 14i. Here, for example, the total size of the plurality of slit hole portions SL1 functioning as an exhaust port may be set in a range of about 1 to 2 times the size of the substantial air intake port. In this case, a smooth flow of air that passes from the external space 14o through the second opening 140b, the internal space 14i, and the third opening 140c in this order and is discharged to the external space 14o can be efficiently generated.

[0095] For example, a configuration is possible in which the length of the second opening 140b in the first direction is 12 mm, the multiple protrusions 122 are 19 fins, the pitch (second pitch) of the multiple protrusions 122 is 6 mm, and the thickness of the multiple protrusions 122 is 2 mm. In this configuration, the actual area of ​​the intake port (also called the effective area of ​​the intake port) is 864 mm. 2 (=12 mm×4 mm×18). For example, the slit holes SL1 in the third opening 140c are 28 L-shaped slits, the pitch (first pitch) of the slit holes SL1 is 4 mm, and each slit hole SL1 has a width of 2 mm, a length (fourth length) of a first elongated portion of 5 mm, and a length (fifth length) of a second elongated portion of 15 mm. In this configuration, the area of ​​the exhaust port of the third opening 140c (also called the exhaust port area) is 1120 mm 2 (=(5 mm+15 mm)×2 mm×28). In this case, the exhaust port area, which is the size of the multiple slit hole portions SL1 functioning as exhaust ports, is larger than the effective intake port area, which is the substantial size of the intake port, and the exhaust port area is about 1.3 times the effective intake port area.

[0096] <1-1-2. Temperature drift in light-emitting elements> A light-emitting element such as an LED element generates heat in response to light emission when turned on, and the illuminance of the light irradiated to an object (illuminated object) may vary due to changes in temperature. For example, in an LED element, a phenomenon occurs in which the illuminance decreases with an increase in temperature (also called temperature drift). When a light-emitting element is turned on, it means that the light-emitting element is in a state in which it is emitting light (also called a light-emitting state). In the present disclosure, the lighting of a light-emitting element and the emission of light by a light-emitting element are synonymous.

[0097] Therefore, an experiment was conducted in which the light irradiation device 1 was fixed with a resin jig in a position where the first outer surface 14a was facing upward, and light was emitted upward from the light source 11 while measuring the temperature of the multiple light-emitting elements 112 and the illuminance of the light from the light source 11.

[0098] Here, 18 LED elements, the peak wavelength of which emitted light (also called LED light) was 395 nanometers (nm), were used as the multiple light-emitting elements 112. The 18 LED elements were arranged in a row at intervals of 6.5 mm on three substrates 111 arranged adjacent to each other in the width direction of the housing 14. Each LED element was made to emit light with a forward current of 0.35 amperes (A). The illuminance of the light from the light source 11 was measured using an illuminometer (UVPF-A2 manufactured by Eye Graphics Co., Ltd.) fixed to a resin jig. The temperature of the multiple light-emitting elements 112 was measured by photographing the 18 LED elements facing downward using a thermograph (InfraRed Camera R500 manufactured by Nippon Avionics Co., Ltd.) fixed to a resin jig. The temperature of the room in which the experiment was performed was set to 25 degrees as a reference temperature.

[0099] FIG. 12 is a diagram showing an example of the relationship between the lighting time of an LED element, the temperature of the LED element, and the illuminance of the LED light emitted from the LED element, obtained by an experiment. The lighting time of an LED element means the time that the LED element continues to emit light from the timing when the LED element starts to emit light. In FIG. 12, the relationship between the lighting time of the LED element and the temperature of the LED element is shown by a plot of multiple black circles, and the relationship between the lighting time of the LED element and the illuminance of the LED light is shown by a plot of multiple white circles. In FIG. 12, the illuminance of the LED light is shown as a percentage relative to the initial value, which is the illuminance at the time when the lighting of the multiple LED elements starts.

[0100] As shown in Figure 12, as time passed after the multiple LED elements started to light up, the temperature of the LED elements increased, and a temperature drift was confirmed in which the illuminance of the LED light decreased as the temperature of the LED elements increased.

[0101] Here, the rate of decrease in illuminance of the LED light due to temperature drift is assumed to be D1 [percent (%)]. The rate of decrease in illuminance of the LED light with respect to a temperature rise of 1 degree (℃) in the LED element is assumed to be d0 [% / ℃]. The temperature reached by the LED element (also called the reached temperature of the LED element) is assumed to be T1 [℃]. The initial temperature of the LED element (also called the initial temperature of the LED element) is assumed to be T0 [℃]. In this case, the temperature drift can be approximately expressed by the following equation (1).

[0102] D1[%]=d0[% / ℃]×(T1[℃]-T0[℃]) ···(1).

[0103] Regarding the temperature drift of the LED element used in the above experiment, d0 [percent (%)] is approximately calculated as 0.18 [% / ℃]. In addition, the initial temperature T0 [℃] of the LED element was 25 [℃] as the reference temperature mentioned above. Therefore, the temperature drift [%] of the LED element used in the above experiment can be approximately expressed by the following formula (2).

[0104] D1[%]=0.18[% / ℃]×(T1[℃]-25[℃]) ···(2).

[0105] Here, if the temperature rise of the multiple LED elements in the light irradiation device 1 is kept below a certain level, the rate of decrease in the illuminance of the light irradiated from the light irradiation device 1 to the object (illuminated object) can be kept below a certain level. This can stabilize the illuminance of the light emitted from the light irradiation device 1. The temperature drift D1 [%] may be targeted to be, for example, 5% or less. In this case, it can be calculated from formula (2) that the temperature drift D1 [%] can be 5% or less if the temperature T1 [°C] of the LED elements is 53°C or less. In other words, for the configuration used in the above experiment, in order to keep the temperature drift D1 [%] at 5% or less, it is necessary to keep the temperature of the LED elements at 53°C or less.

[0106] <1-1-3. Relationship between the height of the second opening and the temperature reached by the light-emitting element> Assume that the light irradiation device 1 is used in a position in which the first outer surface 14a faces downward. In this case, by adjusting the height H of the second opening 140b, which is the length in the +Z direction as the first direction, the temperature reached by the multiple light emitting elements 112 when the multiple light emitting elements 112 are made to emit light can be reduced.

[0107] Here, a simulation was performed to explain the relationship between the height H of the second opening 140b in the +Z direction as the first direction and the temperature reached by the multiple light-emitting elements 112 due to heat generated in response to the light emission of the multiple light-emitting elements 112.

[0108] <<Simulation conditions>> The simulation was performed using thermal fluid analysis software (SOLIDWORKS Flow Simulation) manufactured by Structural Design Engineering Co., Ltd. In the simulation, the following conditions were used as the conditions of the light irradiation device 1.

[0109] The light irradiation device 1 was oriented such that the first outer surface 14a faced downward.

[0110] Regarding the housing 14, the first length, which is the thickness of the housing 14, was set to 30 mm, the second length, which is the width of the housing 14, was set to 120 mm, and the third length, which is the height of the housing 14, was set to 134.8 mm. The corners of the housing 14 were made to be rounded curved surfaces with a radius of curvature of about 0.5 mm. The housing 14 was made to have a structure including a first member, a second member, and a third member, each of which was fixed to the heat dissipation member 12 by screwing. The first member was made to be a portion of the housing 14 that was closer to the first outer surface 14a side than the heat dissipation member 12. The first member was made to be a member that had a length of 120 mm in the width direction of the housing 14, a length of 30 mm in the thickness direction of the housing 14, and a length of 14.8 mm in the height direction of the housing 14. The second portion was made to be a member that included a portion of the fourth wall portion 144, the fifth wall portion 145, and the sixth wall portion 146 from the area along the heat dissipation member 12 to the area along the second wall portion 142. The third member is a member including the second wall portion 142 and a portion of the third wall portion 143 extending from a region along the heat dissipation member 12 to a region along the second wall portion 142. Each of the second member and the third member is a member obtained by bending a plate material having a thickness of 1 mm. The material of the housing 14 is aluminum having a thermal conductivity of 204 [watts per meter per Kelvin (W / (m×K))]. The shape of the first opening 140a when the first outer surface 14a is viewed in a plan view is a shape having a length of about 8.14 mm in the thickness direction of the housing 14 and a length of 120 mm in the width direction of the housing 14, which is the same as the width of the housing 14. The shape of the first opening 140a when the fifth outer surface 14e is viewed in a plan view is a shape having a first circular portion and a first trapezoidal portion having an upper base connected to a portion of the first circular portion on the first outer surface 14a side. The diameter of the first circular portion was set to 10.2 mm. The length of the upper base of the first trapezoidal portion was set to 8.14 mm, and the length of the lower base was set to 13 mm. The shape of the first opening 140a when the sixth outer surface 14f is viewed in plan was set to have a second circular portion and a second trapezoidal portion having an upper base connected to the portion of the second circular portion on the first outer surface 14a side. The diameter of the second circular portion was set to 10.2 mm. The length of the upper base of the second trapezoidal portion was set to 8.14 mm, and the length of the lower base was set to 13 mm.The center points of the first circular portion and the second circular portion were each set to a point that was 10.3 mm away from the heat dissipation member 12 and was located at the center of the housing 14 in the thickness direction.

[0111] The optical system 16 was a glass rod lens having a diameter of 10 mm and a central axis length of 120 mm along the width direction of the housing 14. This rod lens was fitted into both the first circular portion and the second circular portion of the first opening 140a.

[0112] The multiple light emitting elements 112 were 18 LED elements arranged in a row at a pitch of 6.5 mm on three substrates 111 arranged side by side in the width direction of the housing 14. The heat value of the 18 LED elements was 11 watts (W).

[0113] The three substrates 111 were each formed into a plate shape with a length of 39 mm in the width direction of the housing 14, a length of 15 mm in the thickness direction of the housing 14, and a length (also called thickness) of 2 mm in the height direction of the housing 14. The material of the three substrates 111 was copper with a thermal conductivity of 372 [W / (m×K)]. The three substrates 111 were arranged adjacent to each other in the width direction of the housing 14.

[0114] The shape of the base portion 121 of the heat dissipation member 12 was a rectangular parallelepiped with a length of 118 mm in the width direction of the housing 14, a length of 28 mm in the thickness direction of the housing 14, and a length (also called thickness) of 8 mm in the height direction of the housing. The multiple protrusions 122 of the heat dissipation member 12 were 19 fins arranged at a pitch of 6 mm in the width direction of the housing 14. The shape of each fin was a thin plate with a length (also called thickness) of 2 mm in the width direction of the housing 14, a length of 28 mm in the thickness direction of the housing 14, and a length (also called height) of 28 mm in the height direction of the housing. The material of the heat dissipation member 12 was aluminum with a thermal conductivity of 204 [W / (m×K)].

[0115] The shape of the driving unit 13 was a thin plate having a length of 80 mm in the width direction of the housing 14, a length (also called thickness) of 2 mm in the thickness direction of the housing 14, and a length of 100 mm in the height direction of the housing. The material of the wiring board 131 of the driving unit 13 was glass epoxy having a thermal conductivity of 0.38 [W / (m×K)]. The driving unit 13 was disposed parallel to the fourth wall portion 144 at a position 9 mm away from the fourth wall portion 144.

[0116] The second opening 140b has a rectangular shape in plan view. The first end face 143e constituting the edge of the second opening 140b on the first outer surface 14a side and the first face 121u on the second outer surface 14b side of the base part 121 of the heat dissipation member 12 are flush with each other. The length (also called width) of the second opening 140b in the width direction of the housing 14 is 110 mm. The length (height) H of the second opening 140b in the height direction of the housing 14 is set to nine heights: 0 mm, 4 mm, 8 mm, 12 mm, 16 mm, 20 mm, 24 mm, 28 mm, and 32 mm. FIG. 13 is a left side view showing the appearance of an example of the light irradiation device 1 when the height H of the second opening 140b in the +Z direction as the first direction is the first height H1. FIG. 14 is a left side view showing the appearance of an example of the light irradiation device 1 in the case where the height H of the second opening 140b in the +Z direction as the first direction is the second height H2. FIG. 15 is a left side view showing the appearance of an example of the light irradiation device 1 in the case where the height H of the second opening 140b in the +Z direction as the first direction is the third height H3. The second height H2 is greater than the first height H1, and the third height H3 is greater than the second height H2. The first height H1 in the example of FIG. 13 is 8 mm, the second height H2 in the example of FIG. 14 is 24 mm, and the third height H3 in the example of FIG. 15 is 32 mm. In FIG. 13 and FIG. 14, the outer edge of the part of the plurality of protrusions 122 located on the back surface of the third wall portion 143 is typically shown by a thin dashed line that is a hidden line.

[0117] The third opening 140c has 28 slit holes SL1 at a pitch of 4 mm in the width direction of the housing 14. Each slit hole SL1 is an L-shaped slit hole having the same shape and dimensions. The shape of the slit hole SL1 when the third outer surface 14c is viewed in a plane is a rectangle having a length of 15 mm in the height direction of the housing 14 and a length of 2 mm in the width direction of the housing 14. The shape of the slit hole SL1 when the second outer surface 14b is viewed in a plane is a rectangle having a length of 5 mm in the thickness direction of the housing 14 and a length of 2 mm in the width direction of the housing 14.

[0118] <<Simulation results>> Fig. 16 is a diagram showing an example of a result of a simulation on the relationship between the height of the second opening 140b and the temperature reached by the LED element when the LED element is turned on. In Fig. 16, the relationship between the height of the second opening 140b and the temperature reached by the LED element is shown by a plot of multiple filled circles.

[0119] As shown in FIG. 16, a simulation result was obtained in which, when the height of second opening 140b is between 12 mm and 28 mm, the temperature reached by the LED element is 53° C. or less, at which the above-mentioned temperature drift D1 is 5% or less.

[0120] For this reason, it has been confirmed that, for example, when the height of the second opening 140b is equal to or more than half but equal to or less than 28 mm, which is the length (height) of the protrusion 122 of the heat dissipation member 12 in the height direction of the housing 14, the temperature drift D1 can be 5% or less. More specifically, it has been confirmed that, for example, when the height of the second opening 140b is equal to or more than 43% (≒12 / 28×100[%]) but equal to or less than 28 mm, which is the length (height) of the protrusion 122 of the heat dissipation member 12 in the height direction of the housing 14, the temperature drift D1 can be 5% or less.

[0121] Therefore, for example, when the portion of the plurality of gaps 12s on the base portion 121 side is adjacent to the second opening 140b, if the length (height) H of the second opening 140b is half or more of the length of the plurality of protrusions 122 and is equal to or less than the length of the plurality of protrusions 122 in the first direction from the first outer surface 14a to the second outer surface 14b, the cooling performance of the light irradiation device 1 can be improved. More specifically, if the length (height) H of the second opening 140b is 43% or more of the length of the plurality of protrusions 122 and is equal to or less than the length of the plurality of protrusions 122 in the first direction, the cooling performance of the light irradiation device 1 can be improved. Here, the first surface 121u of the base portion 121 may be flush with the first end surface 143e constituting the edge of the second opening 140b on the first outer surface 14a side of the housing 14, or may be slightly shifted from the first end surface 143e toward the first outer surface 14a side or the second outer surface 14b side. In addition, the fact that the length (height) H of the second opening 140b in the first direction is more than half the length of the multiple protrusions 122 does not necessarily mean that the length (height) H of the second opening 140b in the first direction is exactly more than half the length of the multiple protrusions 122. Here, more than half the length of the multiple protrusions 122 may be recognized as more than half with a width that is usually allowed in terms of dimensions. As shown in FIG. 16, when the length (height) H of the second opening 140b in the first direction is about 1 / 3 the length of the multiple protrusions 122, it is not clear that the temperature reached by the LED element will be 53°C or less, and it tends to be difficult to say that the cooling performance of the light irradiation device 1 can be improved. Therefore, the fact that the length (height) H of the second opening 140b in the first direction is more than half the length of the multiple protrusions 122 is an expression based on recognition that allows for a margin for this tendency. A configuration in which the length (height) H of the second opening 140b in the first direction is equal to or greater than half the length of the multiple protrusions 122 may include, for example, a configuration in which the length (height) H of the second opening 140b in the first direction is equal to or greater than 43% of the length of the multiple protrusions 122.

[0122] <1-2. General configuration of the printing device> FIG. 17 is a diagram illustrating a schematic configuration of an example of a printing device 100 according to the first embodiment.

[0123] As shown in FIG. 17, the printing device 100 includes the above-mentioned light irradiation device (also referred to as the first light irradiation device) 1, a transport unit 2, and a printing unit 3. In the example of FIG. 17, the printing device 100 includes three first light irradiation devices 1, a transport unit 2, four printing units 3, another light irradiation device (also referred to as the second light irradiation device) 6, and a control unit (also referred to as the controller) 9. The three first light irradiation devices 1 include a 1A light irradiation device 1a, a 1B light irradiation device 1b, and a 1C light irradiation device 1c. The four printing units 3 include a first printing unit 3a, a second printing unit 3b, a third printing unit 3c, and a fourth printing unit 3d.

[0124] <<Transportation section 2>> The transport unit 2 can transport the print medium 4 in a predetermined direction (also called the second direction or transport direction). The print medium 4 is an object that is to be printed by the printing device 100. The print medium 4 may be, for example, a sheet made of paper or resin, or a thin plate-like material made of resin, semiconductor, metal, wood, or the like.

[0125] In the example of Fig. 17, the transport unit 2 can transport the print medium 4, which is located along a virtual plane parallel to the horizontal plane, in the +X direction as the second direction. In other words, the transport direction is the +X direction. The width direction perpendicular to the transport direction of the print medium 4 is the +Y direction. The thickness direction of the print medium 4 is the +Z direction as the first direction. In Fig. 17, the transport direction is indicated by a thin solid arrow.

[0126] In the example of Figure 17, above the printing medium 4 being transported by the transport unit 2, the first printing unit 3a, the 1A light irradiation device 1a, the second printing unit 3b, the 1B light irradiation device 1b, the third printing unit 3c, the 1C light irradiation device 1c, the fourth printing unit 3d and the second light irradiation device 6 are arranged in the order listed above in the +X direction, which is the transport direction.

[0127] As shown in FIG. 17, the transport unit 2 may have, for example, a pair of transport rollers 21 located upstream of the printing device 100 and a pair of transport rollers 22 located downstream of the printing device 100. The pair of transport rollers 21 hold the print medium 4 by sandwiching it from above and below. The pair of transport rollers 22 hold the print medium 4 by sandwiching it from above and below. The print medium 4 can be transported in the transport direction by the rotation of the pair of transport rollers 21 on the downstream side and the rotation of the pair of transport rollers 22 on the upstream side. The rotation of each of the pair of transport rollers 21 may be achieved by driving an electric motor or the like. The rotation of each of the pair of transport rollers 22 may be achieved by driving an electric motor or the like.

[0128] The transport unit 2 may have a support portion that supports the print medium 4 from below, for example, between a pair of transport rollers 21 on the upstream side and a pair of transport rollers 22 on the downstream side. This support portion may be, for example, a plurality of cylindrical or columnar rollers (also called support rollers). Each of the plurality of support rollers may have an axial direction perpendicular to the transport direction and may be aligned in the transport direction.

[0129] <<Print section 3>> The printing unit 3 can print on the print medium 4. The printing unit 3 is located on the side opposite to the transport direction (second direction) (also called the third direction) with respect to the first light irradiation device 1. The third direction side can also be said to be the upstream side of the transport direction. In other words, the printing unit 3 is located upstream of the first light irradiation device 1 with respect to the transport direction of the print medium 4. In the example of FIG. 17, the third direction is the -X direction.

[0130] In the example of Fig. 17, the first printing unit 3a is located on the -X direction side of the 1A light irradiation device 1a as the third direction. The second printing unit 3b is located on the -X direction side of the 1B light irradiation device 1b as the third direction. The third printing unit 3c is located on the -X direction side of the 1C light irradiation device 1c as the third direction.

[0131] The printing unit 3 is, for example, an ink jet (IJ) head that ejects ink 5. The ink 5 is a photocurable ink (also called photocurable ink) that is a photosensitive material. The photocurable ink is an ink that cures (is photocured) in response to irradiation with light in a specific wavelength range. The photocurable ink is, for example, an ultraviolet curable ink (also called UV ink) that cures (is photocured) in response to irradiation with ultraviolet light as light in a specific wavelength range.

[0132] The printing unit 3 can, for example, eject ink 5 onto the upper surface of the print medium 4 being transported by the transport unit 2, thereby depositing ink 5 onto the upper surface of the print medium 4. Here, the IJ head serving as the printing unit 3 can, for example, eject droplets of ink 5 onto the upper surface of the print medium 4 being transported by the transport unit 2, thereby depositing droplets of ink 5 onto the upper surface of the print medium 4. The printing unit 3 can, for example, deposit ink 5 in a desired pattern onto the upper surface of the print medium 4. The printing unit 3 can, for example, deposit ink 5 over substantially the entire upper surface of the print medium 4, or deposit ink 5 onto a portion of the upper surface of the print medium 4.

[0133] The first printing unit 3a can, for example, deposit the first ink 5a on the upper surface of the print medium 4 being transported by the transport unit 2 by ejecting a first type of ink (also referred to as the first ink) 5a onto the upper surface of the print medium 4. For example, a first color ink is applied as the first ink 5a. A first UV ink (also referred to as the first UV ink) as the first color ink may be applied as the first ink 5a. For example, cyan (Cyan: C) may be applied as the first color.

[0134] The second printing unit 3b can, for example, deposit the second ink 5b on the upper surface of the print medium 4 being transported by the transport unit 2 by ejecting a second type of ink (also referred to as the second ink) 5b onto the upper surface of the print medium 4. For example, ink of a second color is applied as the second ink 5b. A second UV ink (also referred to as the second UV ink) as the ink of the second color may be applied as the second ink 5b. For example, magenta (M) may be applied as the second color.

[0135] The third printing unit 3c can, for example, deposit the third ink 5c on the upper surface of the print medium 4 being transported by the transport unit 2 by ejecting a third type of ink (also referred to as the third ink) 5c onto the upper surface of the print medium 4 being transported by the transport unit 2. For example, an ink of a third color is applied as the third ink 5c. A third UV ink (also referred to as the third UV ink) as the ink of the third color may be applied as the third ink 5c. For example, yellow (Y) may be applied as the third color.

[0136] The fourth printing unit 3d can, for example, deposit the fourth ink 5d on the upper surface of the print medium 4 being transported by the transport unit 2 by ejecting a fourth type of ink (also referred to as the fourth ink) 5d onto the upper surface of the print medium 4. For example, a fourth color ink is applied as the fourth ink 5d. A fourth UV ink (also referred to as the fourth UV ink) as the fourth color ink may be applied as the fourth ink 5d. For example, black (Black: K) may be applied as the fourth color.

[0137] Here, for example, the first color may be any color among cyan, magenta, yellow, and black. For example, the second color may be any color different from the first color among cyan, magenta, yellow, and black. For example, the third color may be any color different from the first color and the second color among cyan, magenta, yellow, and black. For example, the fourth color may be any color different from the first color, the second color, and the third color among cyan, magenta, yellow, and black.

[0138] Here, for example, a line-type IJ head may be applied to the IJ head as the printing unit 3. The line-type IJ head has a plurality of ink ejection holes arranged in a line (linear). The line-type IJ head can eject ink 5 from each of the plurality of ink ejection holes. The direction in which the plurality of ink ejection holes are arranged (also referred to as the arrangement direction) is, for example, a direction perpendicular to the transport direction of the print medium 4 by the transport unit 2 and parallel to the upper surface of the print medium 4 being transported by the transport unit 2. In other words, the width direction perpendicular to the transport direction of the print medium 4 being transported by the transport unit 2 may be applied to the arrangement direction of the plurality of ink ejection holes. In the example of FIG. 17, the +Y direction is applied to the arrangement direction of the plurality of ink ejection holes. With this configuration, the ink 5 can be applied to the upper surface of the print medium 4 by ejecting ink 5 from the plurality of ink ejection holes of the line-type IJ head onto the print medium 4 being transported in the transport direction by the transport unit 2. As a result, printing can be performed on the upper surface of the print medium 4 by the printing unit 3.

[0139] The IJ head serving as the printing unit 3 may be, for example, an IJ head of another type, such as a serial IJ head that is different from a line IJ head. The serial IJ head is movable in the width direction of the print medium 4. In this case, the printing unit 3 can print on the upper surface of the print medium 4 by alternating between printing on the upper surface of the print medium 4 while the serial IJ head is moving in the width direction of the print medium 4 and moving the print medium 4 in the transport direction by the transport unit 2.

[0140] <<First light irradiation device 1>> The first light irradiation device 1 can irradiate light from the first opening 140a to the print medium 4 being transported in the transport direction by the transport unit 2. The first light irradiation device 1 is located downstream of the printing unit 3 in the transport direction in which the print medium 4 is transported by the transport unit 2. A first outer surface 14a of the first light irradiation device 1 faces downward.

[0141] As described above, the cooling performance of the first light irradiation device 1 can be improved without providing a cooling fan. This can reduce the occurrence of forced turbulence of airflow caused by a cooling fan or the like. This can reduce the influence of turbulence of airflow on the ejection of ink 5 by the printing unit 3 onto the upper surface of the print medium 4 and the landing of droplets of ink 5 on the upper surface of the print medium 4 in the printing device 100. In addition, since the printing unit 3 and the first light irradiation device 1 can be arranged close to each other, the printing device 100 can be made smaller.

[0142] In the example of FIG. 17, the first light irradiation device 1 can irradiate the upper surface of the print medium 4 with light from the first opening 140a of the downward-facing first outer surface 14a. In FIG. 17, the outer edge of the light directed from the first light irradiation device 1 to the upper surface of the print medium 4 is shown by a dashed line. When the ink 5 is a photocurable ink, if the light irradiated to the upper surface of the print medium 4 by the first light irradiation device 1 is light in a specific wavelength range for causing curing (photocuring) of the photocurable ink, the ink 5 attached to the upper surface of the print medium 4 can be cured by the light from the first light irradiation device 1. For example, when the ink 5 is an ultraviolet-curable ink (UV ink), if the light irradiated to the upper surface of the print medium 4 by the first light irradiation device 1 is ultraviolet light in a specific wavelength range, the UV ink as the ink 5 attached to the upper surface of the print medium 4 can be cured.

[0143] For example, if the first ink 5a is a photocurable ink, the 1A light irradiation device 1a can cure the first ink 5a adhered to the upper surface of the printing medium 4 by irradiating the first ink 5a adhered to the upper surface of the printing medium 4 by the first printing unit 3a with light in a specific wavelength range.

[0144] For example, if the second ink 5b is a photocurable ink, the 1B light irradiation device 1b can cure the second ink 5b adhered to the upper surface of the printing medium 4 by irradiating the second ink 5b adhered to the upper surface of the printing medium 4 by the second printing unit 3b with light in a specific wavelength range.

[0145] For example, if the third ink 5c is a photocurable ink, the 1C light irradiation device 1c can cure the third ink 5c adhered to the upper surface of the printing medium 4 by irradiating the third ink 5c with light in a specific wavelength range onto the third ink 5c adhered to the upper surface of the printing medium 4 by the third printing unit 3c.

[0146] Here, for example, as described above, if the housing 14 of the first light irradiation device 1 is a thin rectangular parallelepiped, the first light irradiation device 1 may be disposed in each gap between the four printing units 3 in the transport direction of the print medium 4 by the transport unit 2. Here, the thickness direction of the housing 14 of the first light irradiation device 1 may be disposed along the transport direction of the print medium 4 by the transport unit 2. Note that in the example shown in FIG. 17, the first light irradiation device 1 (the 1A light irradiation device 1a, the 1B light irradiation device 1b and / or the 1C light irradiation device 1c) is disposed with the third outer surface 14c facing the -X direction and the fourth outer surface 14d facing the +X direction with respect to the +X direction as the second direction, and the direction from the third outer surface 14c to the fourth outer surface 14d is disposed as the second direction, but these arrangements may be reversed. That is, the first light irradiation device 1 (the 1A light irradiation device 1a, the 1B light irradiation device 1b, and / or the 1C light irradiation device 1c) may be arranged with the fourth outer surface 14d facing the -X direction and the third outer surface 14c facing the +X direction as the second direction, with the direction from the fourth outer surface 14d to the third outer surface 14c being the second direction. Therefore, the second direction with respect to the light irradiation device 1 may be either of the directions including the direction from the third outer surface 14c to the fourth outer surface 14d and the direction from the fourth outer surface 14d to the third outer surface 14c, as long as it is along the thickness direction of the housing 14. In other words, the conveying unit 2 may be capable of conveying the printing medium 4 irradiated with light from the first opening 140a in the second direction, which is either the direction from the third outer surface 14c to the fourth outer surface 14d or the direction from the fourth outer surface 14d to the third outer surface 14c.

[0147] <<Second light irradiation device 6>> The second light irradiation device 6 can irradiate light onto the print medium 4 being transported in the transport direction by the transport unit 2. In the example of FIG. 17, the second light irradiation device 6 can irradiate the light onto the upper surface of the print medium 4 by emitting light downward. In FIG. 17, the outer edge of the light directed from the second light irradiation device 6 to the upper surface of the print medium 4 is shown by a dashed line. In the case where the ink 5 is a photocurable ink, if the light irradiated onto the upper surface of the print medium 4 by the second light irradiation device 6 is light in a specific wavelength range for causing curing (photocuring) of the photocurable ink, the ink 5 attached to the upper surface of the print medium 4 can be cured by the light from the second light irradiation device 6. For example, in the case where the ink 5 is an ultraviolet ray curable ink (UV ink), if the light irradiated onto the upper surface of the print medium 4 by the second light irradiation device 6 is ultraviolet ray as light in a specific wavelength range, the ink 5 attached to the upper surface of the print medium 4 can be cured.

[0148] Here, the intensity of the light in the specific wavelength range emitted by the second light irradiation device 6 may be greater than the intensity of the light in the specific wavelength range emitted by the first light irradiation device 1. In this case, if the ink 5 is a photocurable ink, the ink 5 attached to the upper surface of the print medium 4 may be cured to a certain extent (also called provisional curing) by the light in the specific wavelength range emitted from the first light irradiation device 1, and then may be further cured (also called full curing) by the light in the specific wavelength range emitted from the second light irradiation device 6.

[0149] In the printing device 100 of the example of FIG. 17, if the ink 5 is a photocurable ink, the following operation is possible. First, the first printing unit 3a deposits droplets of the first ink 5a on the upper surface of the print medium 4. Next, the 1A light irradiation device 1a emits light in a specific wavelength range toward the upper surface of the print medium 4, so that the droplets of the first ink 5a deposited on the upper surface of the print medium 4 are temporarily cured. Next, the second printing unit 3b deposits droplets of the second ink 5b on the upper surface of the print medium 4. Next, the 1B light irradiation device 1b emits light in a specific wavelength range toward the upper surface of the print medium 4, so that the droplets of the second ink 5b deposited on the upper surface of the print medium 4 are temporarily cured. Next, the third printing unit 3c deposits droplets of the third ink 5c on the upper surface of the print medium 4. Next, the first light irradiation device 1c emits light in a specific wavelength range toward the upper surface of the print medium 4, thereby partially curing the droplets of the third ink 5c adhering to the upper surface of the print medium 4. Next, the fourth printing unit 3d causes droplets of the fourth ink 5d to adhere to the upper surface of the print medium 4. Then, the second light irradiation device 6 irradiates light in a specific wavelength range toward the upper surface of the print medium 4, thereby fully curing the droplets of the first ink 5a, the second ink 5b, and the third ink 5c that have partially cured on the upper surface of the print medium 4, and curing the droplets of the fourth ink 5d adhering to the upper surface of the print medium 4.

[0150] According to this operation, after the droplets of the first ink 5a have hardened to a certain degree on the upper surface of the print medium 4, the droplets of the second ink 5b are applied. Therefore, on the upper surface of the print medium 4, the occurrence of mixing of the first ink 5a and the second ink 5b due to contact between the droplets of the first ink 5a and the droplets of the second ink 5b can be reduced. Furthermore, on the upper surface of the print medium 4, the droplets of the third ink 5c are applied after the droplets of the first ink 5a and the second ink 5b have hardened to a certain degree. Therefore, on the upper surface of the print medium 4, the occurrence of mixing of the ink due to contact between the droplets of the first ink 5a, the droplets of the second ink 5b, and the droplets of the third ink 5c can be reduced. Furthermore, on the upper surface of the print medium 4, the droplets of the fourth ink 5d are applied after the droplets of the first ink 5a, the second ink 5b, and the third ink 5c have hardened to a certain degree. This can reduce the occurrence of ink mixing due to contact between the droplets of the first ink 5a, the droplets of the second ink 5b, the droplets of the third ink 5c, and the droplets of the fourth ink 5d on the upper surface of the print medium 4. This can reduce the occurrence of defects such as ink bleeding and color mixing on the upper surface of the print medium 4 in the printing device 100, improving the quality of the printed ink pattern.

[0151] Fig. 18 is a plan view showing a schematic example of the form of four types of inks 5 attached to the upper surface of the print medium 4. In Fig. 18, droplets of the first ink 5a are shown as circles hatched with diagonal lines slanting upwards to the left. Droplets of the second ink 5b are shown as circles hatched with diagonal lines slanting upwards to the right. Droplets of the third ink 5c are shown as circles hatched with sandy patterns. Droplets of the fourth ink 5d are shown as circles filled with black.

[0152] <<Control unit 9>> The control unit 9 can control the operation of each part of the printing device 100. The control unit 9 has various electric circuits such as a processor and a memory. The control unit 9 is electrically connected to each part of the printing device 100 using a cable or the like. For example, the control unit 9 may be electrically connected to the connector 17 of the first light irradiation device 1 via a cable or the like. The control unit 9 may be electrically connected to the connector 67 of the second light irradiation device 6 via a cable or the like. The control unit 9 may be electrically connected to the transport unit 2 and the printing unit 3 via a cable or the like.

[0153] The control unit 9 can, for example, control the transportation of the print medium 4 by the transport unit 2. The control unit 9 can, for example, control the ejection of ink by an IJ head serving as the printing unit 3. The control unit 9 can, for example, control the light emission of each of the first light irradiation device 1 and the second light irradiation device 6.

[0154] For example, if the ink 5 is a photocurable ink, the memory of the control unit 9 may store information indicating characteristics of light capable of relatively well performing photocuring of the ink 5 discharged from the IJ head as the printing unit 3. Specific examples of this information include numerical values ​​indicating the characteristics of the wavelength distribution of light suitable for causing photocuring of the droplets of the ink 5 discharged from the IJ head and the intensity of the light (emission intensity of each wavelength range). In the printing device 100, for example, the control unit 9 may adjust the magnitude of the drive current input to the multiple light emitting elements 112 in the light source 11 of the first light irradiation device 1 based on the information in the memory. This allows, for example, the first light irradiation device 1 to emit light with an appropriate amount of light according to the characteristics of the ink used, and the ink 5 to be cured with light of relatively low energy. In addition, the control unit 9 may adjust the magnitude of the drive current input to the light emitting elements of the second light irradiation device 6 based on the information in the memory.

[0155] <<Size of the first light irradiation device>> Here, for example, it is assumed that the printing device 100 has the form of a line printer in which the width of the IJ head as the printing unit 3 is approximately the same as the width of the print medium 4. In this case, for example, by arranging a plurality of first light irradiation devices 1 in the +Y direction as the width direction of the print medium 4, the width of the print medium 4 and the total width of the plurality of first light irradiation devices 1 may be made approximately the same. Here, for example, the first length, the second length, and the third length of the first light irradiation device 1 may be appropriately set within a range that satisfies the condition that the width of the print medium 4 and the total width of the plurality of first light irradiation devices 1 are approximately the same in the +Y direction as the width direction of the print medium 4.

[0156] For example, the width of the print medium 4 and the total width of the multiple 1A light irradiation devices 1a may be made substantially the same by arranging multiple 1A light irradiation devices 1a in the +Y direction, which is the width direction of the print medium 4. Here, for example, the first length, second length, and third length of the 1A light irradiation device 1a may be appropriately set within a range that satisfies the condition that the width of the print medium 4 and the total width of the multiple 1A light irradiation devices 1a are substantially the same in the +Y direction, which is the width direction of the print medium 4.

[0157] For example, the width of the print medium 4 and the total width of the multiple 1B light irradiation devices 1b may be made substantially the same by arranging multiple 1B light irradiation devices 1b in the +Y direction, which is the width direction of the print medium 4. Here, for example, the first length, second length, and third length of the 1B light irradiation device 1b may be appropriately set within a range that satisfies the condition that the width of the print medium 4 and the total width of the multiple 1B light irradiation devices 1b are substantially the same in the +Y direction, which is the width direction of the print medium 4.

[0158] For example, the width of the print medium 4 and the total width of the multiple 1C light irradiation devices 1c may be made substantially the same by arranging multiple 1C light irradiation devices 1c in the +Y direction, which is the width direction of the print medium 4. Here, for example, the first length, second length, and third length of the 1C light irradiation device 1c may be appropriately set within a range that satisfies the condition that the width of the print medium 4 and the total width of the multiple 1C light irradiation devices 1c are substantially the same in the +Y direction, which is the width direction of the print medium 4.

[0159] <<Fixing of the first light irradiation device in the printing device>> Fig. 19 is a front view showing an example of the light irradiation device (first light irradiation device) 1 fixed to the fixed portion 7 of the printing device 100. In Fig. 19, the outer edges of the base portion 121 and the protrusion portion 122 of the heat dissipation member 12 located inside the light irradiation device (first light irradiation device) 1 are diagrammatically shown by thin dashed lines that are hidden lines.

[0160] The printing device 100 includes, for example, a portion (also called a fixed portion) 7 to which the first light irradiation device 1 is fixed. The fixed portion 7 may be fixed to, for example, a housing or a base of the printing device 100. The fixed portion 7 may be made of a material such as aluminum or stainless steel, which has excellent thermal conductivity. The fixed portion 7 may be, for example, a thick plate-like portion.

[0161] The first light irradiation device 1 may be fixed to the fixed part 7 by fastening such as screwing. In the example of FIG. 19, the fixed part 7 may be a thick plate-like part having a plate surface along a virtual plane parallel to the YZ plane. The shaft part 8a of the male screw member 8 inserted into a through hole part (also called a first through hole part) 7h penetrating the fixed part 7 in the -X direction may be fitted into a screw hole part Sh1 penetrating the fourth wall part 144 of the first light irradiation device 1. A bolt having a head part 8h and a shaft part 8a protruding from the head part 8h may be applied to the male screw member 8. A long and thin cylindrical part having a helical male screw part on the outer periphery may be applied to the shaft part 8a of the male screw member 8. A part in which a helical female screw part is located on the inner periphery of a through hole may be applied to the screw hole part Sh1. In this case, the fixed portion 7 has a first through hole portion 7h, and the printing device 100 has a male screw member 8 that fixes the first light irradiation device 1 to the fixed portion 7. In Fig. 19, the outer edges of the screw hole portion Sh1, the first through hole portion 7h, and the shaft portion 8a are each shown diagrammatically by a thin dashed line that is a hidden line. Here, for example, the first through hole portion 7h may be a screw hole portion having a spiral female screw portion on the inner periphery.

[0162] Here, for example, as shown in Fig. 3, the fourth wall portion 144 may have a first screw hole portion Sh1 and a second screw hole portion Sh1, and the fixed portion 7 may have a first first through hole portion 7h and a second first through hole portion 7h. In this case, the shaft portion 8a of the first male screw member 8 inserted into the first first through hole portion 7h penetrating the fixed portion 7 in the -X direction may be fitted into the first screw hole portion Sh1 penetrating the fourth wall portion 144 of the first light irradiation device 1. The shaft portion 8a of the second male screw member 8 inserted into the second first through hole portion 7h penetrating the fixed portion 7 in the -X direction may be fitted into the second screw hole portion Sh1 penetrating the fourth wall portion 144 of the first light irradiation device 1.

[0163] In this manner, by fixing the first light irradiation device 1 to the fixed portion 7 by screwing at multiple locations using multiple male screw members 8, the first light irradiation device 1 can be stably fixed in the printing device 100. Here, for example, the first light irradiation device 1 may be fixed to the fixed portion 7 by screwing at three or more locations using three or more male screw members 8.

[0164] Here, the fixed part 7 may have an outer surface (also referred to as a seventh outer surface) 7s with which the fourth outer surface 14d of the housing 14 of the first light irradiation device 1 is in surface contact. For example, if the housing 14 is in contact with the heat dissipation member 12 in the first light irradiation device 1, the heat dissipation member 12 can be cooled more efficiently by heat transfer from the heat dissipation member 12 to the fixed part 7 via the housing 14. Here, surface contact includes contact between flat surfaces. For example, a state in which the fourth outer surface 14d is in surface contact with the seventh outer surface 7s includes a state in which a flat portion of the fourth outer surface 14d is in contact with a flat portion of the seventh outer surface 7s.

[0165] Here, for example, a member different from the male screw member 8 may be used as the member that fixes the first light irradiation device 1 to the fixed portion 7. For example, a member that fixes the first light irradiation device 1 to the fixed portion 7 by clamping it may be used as the different member. For example, a clamp member may be used as a specific example of the different member. For example, this clamp member may be fixed to the fixed portion 7 and clamp the first light irradiation device 1, or may clamp the fixed portion 7 and the first light irradiation device 1 together to fix the first light irradiation device 1 to the fixed portion 7.

[0166] FIG. 20 is a right side view showing the appearance of a light irradiation device (first light irradiation device) 1 according to another example of the first embodiment. FIG. 21 is a right side view showing the appearance of another example of the heat dissipation member 12. FIG. 22 is a front view showing the appearance of another example of the heat dissipation member 12. FIG. 23 is a front view showing another example of the light irradiation device (first light irradiation device) 1 in a state fixed to the fixed portion 7 of the printing device 100. In FIG. 23, the outer edges of the base portion 121 and the protrusion portion 122 of the heat dissipation member 12 located inside the light irradiation device (first light irradiation device) 1 are typically shown by thin dashed lines that are hidden lines.

[0167] Here, for example, as shown in FIG. 21 and FIG. 22, the base portion 121 of the heat dissipation member 12 of the first light irradiation device 1 may have a screw hole portion Sh2 on the side of the fourth outer surface 14d. In FIG. 22 and FIG. 23, the outer edge of the screw hole portion Sh2 is typically shown by a thin dashed line that is a hidden line. The screw hole portion Sh2 may be, for example, a portion having a spiral female screw portion on the inner periphery of a cylindrically recessed hole portion. Furthermore, as shown in FIG. 20, the housing 14 of the first light irradiation device 1 may have a through hole portion (also called a second through hole portion) 144h that opens on the fourth outer surface 14d and is connected to the screw hole portion Sh2. In FIG. 23, the outer edges of the first through hole portion 7h, the second through hole portion 144h, and the shaft portion 8a are typically shown by a thin dashed line that is a hidden line. 23, the male screw member 8 may pass through the first through hole portion 7h and the second through hole portion 144h and be fitted into the screw hole portion Sh2. More specifically, the shaft portion 8a of the male screw member 8 may pass through the first through hole portion 7h and the second through hole portion 144h and be fitted into the screw hole portion Sh2.

[0168] According to this configuration, the first light irradiation device 1 can be easily fixed to the fixed part 7 in a state where the fourth outer surface 14d of the housing 14 and the seventh outer surface 7s of the fixed part 7 are in surface contact. Then, the heat transfer from the heat dissipation member 12 to the fixed part 7 via the housing 14 can be increased. As a result, efficient cooling of the heat dissipation member 12 using heat transfer can be easily achieved. Here, if the material of the male screw member 8 is a metal having excellent thermal conductivity, more efficient cooling of the heat dissipation member 12 can be achieved. For example, the first through hole portion 7h may be a screw hole portion having a spiral female screw portion on the inner periphery, and the second through hole portion 144h may be a screw hole portion having a spiral female screw portion on the inner periphery.

[0169] Here, for example, as in the example of Fig. 20, the fourth wall portion 144 may have a first second through hole portion 144h and a second second through hole portion 144h, and the fixed portion 7 may have a first first through hole portion 7h and a second first through hole portion 7h. Furthermore, as in the examples of Fig. 21 and Fig. 22, the base portion 121 may have a first screw hole portion Sh2 connected to the first second through hole portion 144h, and a second screw hole portion Sh2 connected to the second second through hole portion 144h.

[0170] In this case, for example, the shaft portion 8a of the first male screw member 8 penetrating the first first through hole portion 7h penetrating the fixed portion 7 in the -X direction and the first second through hole portion 144h penetrating the housing 14 in the -X direction may be fitted into the first screw hole portion Sh2 of the base portion 121. For example, the shaft portion 8a of the second male screw member 8 penetrating the second first through hole portion 7h penetrating the fixed portion 7 in the -X direction and the second second through hole portion 144h penetrating the housing 14 in the -X direction may be fitted into the second screw hole portion Sh2 of the base portion 121.

[0171] In this manner, by fixing the first light irradiation device 1 to the fixed portion 7 by screwing at multiple locations using multiple male screw members 8, the first light irradiation device 1 can be stably fixed in the printing device 100. Here, for example, the first light irradiation device 1 may be fixed to the fixed portion 7 by screwing at three or more locations using three or more male screw members 8.

[0172] <1-3. Summary of the first embodiment> In the light irradiation device 1 according to the first embodiment, the second opening 140b opens in a region of the third outer surface 14c on the first outer surface 14a side and connects the internal space 14i of the housing 14 to the external space 14o. The third opening 140c opens in a region extending from the second outer surface 14b to the second outer surface 14b side of the third outer surface 14c and connects the internal space 14i of the housing 14 to the external space 14o. The heat dissipation member 12 includes a base portion 121 located in a region of the internal space 14i on the first outer surface 14a side, and a plurality of protrusions 122 each protruding from the base portion 121 toward the second outer surface 14b along the first direction. The light source 11 is located on the first outer surface 14a side of the base portion 121. A plurality of gaps 12s between the plurality of protrusions 122 are adjacent to the second opening 140b. The drive portion 13 is located in the internal space 14i between the multiple protrusions 122 and the second outer surface 14b.

[0173] According to this configuration, when the first outer surface 14a is arranged facing downward, the third opening 140c is located from the upward second outer surface 14b to the upper part of the third outer surface 14c. Therefore, even if the connector 17 or the like is present on the second outer surface 14b side, the size of the opening required for exhausting air from the internal space 14i to the external space 14o is ensured in the third opening 140c, and the distance between the multiple protrusions 122 and the third opening 140c can be long. As a result, a smooth upward air current is generated from the multiple gaps 12s between the multiple protrusions 122 toward the third opening 140c, and the speed of the upward air current can be increased by the chimney effect. As a result, the heat dissipation member 12 can be efficiently cooled. Therefore, the heat dissipation member 12 can be efficiently cooled without providing a cooling fan in the light irradiation device 1. Therefore, the light irradiation device 1 can be made compact, the structure can be simplified, and the number of failures can be reduced, while the cooling performance can be improved.

[0174] <2. Other embodiments> The present disclosure is not limited to the first embodiment described above, and various modifications and improvements are possible without departing from the gist of the present disclosure.

[0175] In the first embodiment, for example, the shape of each of the multiple protrusions 122 of the heat dissipation member 12 is not limited to a thin plate shape, and may be another shape such as a rod shape.

[0176] In the first embodiment, for example, a mesh member may be disposed in the second opening 140b. This can reduce the intrusion of foreign matter from the external space 14o to the internal space 14i of the housing 14. The foreign matter can include, for example, dust, dirt, metal parts, tools, and the like.

[0177] In the first embodiment, for example, the external space 14o and the internal space 14i of the light irradiation device 1 may be filled with a gas such as an inert gas including nitrogen gas instead of air. In this case, the flow of air passing from the external space 14o through the second opening 140b, the internal space 14i, and the third opening 140c in this order and discharged to the external space 14o becomes a gas flow.

[0178] In the first embodiment, for example, the printing device 100 may have two or more printing units 3, such as three printing units 3, instead of four printing units 3. For example, when the printing device 100 has three printing units 3, the fourth printing unit 3d and the first C light irradiation device 1c may be omitted in the example of FIG. 17. In this case, for example, red (Red:R), green (Green:G) and blue (Blue:B) may be applied to the first color, the second color and the third color. Here, for example, the first color may be any color among red (R), green (G) and blue (B). For example, the second color may be any color different from the first color among red (R), green (G) and blue (B). For example, the third color may be any color different from the first color and the second color among red (R), green (G) and blue (B).

[0179] In the first embodiment, for example, the printing device 100 may include one or more first light irradiation devices 1 instead of the three first light irradiation devices 1. For example, when the printing device 100 has three printing units 3, the fourth printing unit 3d and the first C light irradiation device 1c may be omitted in the example of FIG. 17. For example, when the printing device 100 has two printing units 3, the third printing unit 3c, the fourth printing unit 3d, the first B light irradiation device 1b, and the first C light irradiation device 1c may be omitted in the example of FIG. 17.

[0180] In the first embodiment, for example, the IJ head serving as the printing unit 3 may eject water-based or oil-based ink instead of photocurable ink as the ink 5. In this case, for example, the light irradiated onto the upper surface of the print medium 4 by the first light irradiation device 1 may be light in a specific wavelength range including infrared rays for drying and fixing the ink 5 attached to the upper surface of the print medium 4.

[0181] In the first embodiment, for example, the printing unit 3 is not limited to a configuration having an IJ head, and may have another configuration different from an IJ head. For example, an electrostatic head may be applied to the printing unit 3. The electrostatic head may be a head that charges the print medium 4 and adheres the developer (toner) by electrostatic force due to the static electricity of the print medium 4. The printing unit 3 may be applied with a configuration that transports the developer (toner) using a brush, roller, or the like. Here, for example, an ultraviolet-curable toner that hardens in response to irradiation with ultraviolet light, or a thermosetting toner that hardens in response to irradiation with infrared light, may be applied to the developer.

[0182] In the first embodiment, for example, the ink 5 may be changed to a photosensitive material such as a photosensitive resist or a photocurable resin.

[0183] In the above first embodiment, for example, the light irradiation device 1 is applied to the printing device 100 equipped with the printing unit 3, but the present invention is not limited to this. For example, the light irradiation device 1 may be applied to an apparatus for curing a photosensitive resin after applying a paste containing a photosensitive resin such as a resist to a surface of an object such as a substrate by spin coating or screen printing. Also, for example, the light irradiation device 1 may be applied as a light source for exposure in an exposure apparatus that exposes a photosensitive resin such as a resist to light.

[0184] In the first embodiment, for example, the light irradiation device 1 may be applied to a field other than the printing field such as the printing device 100.

[0185] For example, the present invention may be applied to the field of assembly manufacturing, including applications such as curing adhesives or resins in mounting electronic components. The curing of the adhesive or resin may be a certain degree of curing (temporary curing) of the adhesive or resin. Here, for example, if the adhesive is an ultraviolet curing adhesive, the adhesive may be cured by ultraviolet light emitted from the light irradiation device 1. For example, if the adhesive is a thermosetting adhesive, the adhesive may be cured by infrared light emitted from the light irradiation device 1. For example, if the adhesive is an adhesive that cures by drying, the adhesive may be dried and cured by infrared light emitted from the light irradiation device 1. For example, if the resin is an ultraviolet curing resin that cures in response to irradiation with ultraviolet light, the ultraviolet curing resin may be cured by ultraviolet light emitted from the light irradiation device 1.

[0186] For example, the light irradiation device 1 may be applied to a drying processing field such as an application for efficiently drying an irradiated object by irradiating infrared rays. For example, the light irradiation device 1 may be applied to a medical field such as an application for sterilization by irradiating ultraviolet rays or purple light.

[0187] As described above, the light irradiation device 1 and the printing device 100 have been described in detail, but the above description is merely an example in all respects, and this disclosure is not limited thereto. In addition, the above-mentioned various examples can be combined as long as they are not mutually contradictory. And, countless examples not illustrated can be envisioned without departing from the scope of this disclosure.

[0188] This disclosure includes the following:

[0189] In one embodiment, (1) a light irradiation device includes a light source including a plurality of light-emitting elements, a heat dissipation member thermally connected to the light source, a drive unit including a drive circuit for driving the light source, and a rectangular parallelepiped housing that houses the light source, the heat dissipation member, and the drive unit, the housing having a rectangular first outer surface, a rectangular second outer surface opposite to the first outer surface, a rectangular third outer surface connecting the first outer surface and the second outer surface, a rectangular fourth outer surface connecting the first outer surface and the second outer surface and opposite to the third outer surface, a rectangular fifth outer surface connecting the first outer surface and the second outer surface and connecting the third outer surface and the fourth outer surface, and a rectangular sixth outer surface connecting the first outer surface and the second outer surface, connecting the third outer surface and the fourth outer surface, and opposite to the fifth outer surface, and the housing is open at least at the first outer surface. The housing has a first opening, both of which allow light from the light source to pass through, a second opening, which opens in a region on the first outer surface side of the third outer surface and connects the internal space of the housing to the external space, and a third opening, which opens in a region from the second outer surface to the second outer surface side of the third outer surface and connects the internal space to the external space, and the heat dissipation member includes a base portion located in the first outer surface side region of the internal space, and a plurality of protrusions each protruding from the base portion toward the second outer surface along a first direction from the first outer surface to the second outer surface, the light source is located on the first outer surface side of the base portion, a plurality of gaps between the plurality of protrusions are adjacent to the second opening, and the drive unit is located in the internal space between the plurality of protrusions and the second outer surface.

[0190] (2) In the light irradiation device of (1) above, in the first direction, the length of the second opening is equal to or less than the length of the multiple protrusions, and the portion of the multiple gaps on the base side may be adjacent to the second opening.

[0191] (3) In the light irradiation device of (2) above, the housing may have a first inner surface located on the third outer surface side of the internal space, and the portions of the multiple protrusions on the second outer surface side may be in contact with the first inner surface.

[0192] (4) In any one of the light irradiation devices (1) to (3) above, the driving circuit may include one or more electronic components, which are located between the second opening and the third opening in the first direction, and the driving unit may be located in a region of the internal space closer to the fourth outer surface than the third outer surface, and the one or more electronic components may be positioned with the one or more electronic components facing the third outer surface.

[0193] In one embodiment, (5) the printing device includes any one of the light irradiation devices (1) to (4) above, a transport unit that transports the printing medium onto which light from the first opening is irradiated in a second direction from the third outer surface to the fourth outer surface or from the fourth outer surface to the third outer surface, and a printing unit located on the third direction side opposite to the second direction of the light irradiation device, and the first outer surface is located facing downward.

[0194] (6) The printing device of (5) above may include a fixed portion to which the light irradiation device is fixed, the housing is in contact with the heat dissipation member, and the fixed portion may have a seventh outer surface with which the fourth outer surface of the housing is in face-to-face contact.

[0195] (7) The printing device of (6) above may include a male screw member that fixes the light irradiation device to the fixed portion, the fixed portion having a first through hole portion, the base portion having a threaded hole portion on the side of the fourth outer surface, the housing having a second through hole portion that opens at the fourth outer surface and is connected to the threaded hole portion, and the male screw member may pass through the first through hole portion and the second through hole and be fitted into the threaded hole portion. [Explanation of symbols]

[0196] 1 Light irradiation device (first light irradiation device) 100 Printing device 11 Light source 112 Light emitting element 12 Heat dissipation material 121 Base 122 Protrusion 12s Gap 13 Drive unit 132 Drive circuit 132i Electronic Components 14. Chassis 140a 1st opening 140b 2nd opening 140c 3rd opening 144h 2nd through hole section 14a 1st outer surface 14b 2nd outer surface 14c 3rd outer surface 14d 4th outer surface 14e 5th outer surface 14f 6th outer surface 14i interior space 14o outside space 2. Conveyor section 3 Printing Department 4 Printing medium 5. Ink 6 Second light irradiation device 7 Fixed part 7h 1st through hole section 7s 7th outer surface 8 Male threaded member Iw1 First inner surface SL1 Slit hole Sh2 screw hole

Claims

1. a light source including a plurality of light emitting elements; a heat dissipation member thermally connected to the light source; A driving unit including a driving circuit for driving the light source; a rectangular parallelepiped housing that houses the light source, the heat dissipation member, and the drive unit, There is no blower section inside the housing, at a position in contact with the outside of the housing, or at an opening of the housing; the housing has a first outer surface, a second outer surface, a third outer surface, a fourth outer surface, a fifth outer surface, and a sixth outer surface; The first outer surface is a rectangular surface, the second outer surface is a rectangular outer surface of the housing on an opposite side to the first outer surface, the third outer surface is a rectangular outer surface connecting the first outer surface and the second outer surface of the housing, the fourth outer surface is a rectangular outer surface that connects the first outer surface and the second outer surface of the housing and is opposite to the third outer surface, the fifth outer surface is a rectangular outer surface that connects the first outer surface and the second outer surface of the housing and connects the third outer surface and the fourth outer surface of the housing, the sixth outer surface is a rectangular outer surface that connects the first outer surface and the second outer surface of the housing, connects the third outer surface and the fourth outer surface of the housing, and is an outer surface opposite to the fifth outer surface, The housing has a first opening, a second opening, and a third opening, the first opening is open at least on the first outer surface and allows light from the light source to pass therethrough; the second opening is open in a region of the third outer surface on the first outer surface side, connects an internal space and an external space of the housing, and serves as an air intake from the external space to the internal space; the third opening is open on each of the second outer surface and the third outer surface in a region extending from the second outer surface to a portion of the third outer surface on the second outer surface side, connects the internal space and the external space, and serves as an exhaust port from the internal space to the external space, The heat dissipation member includes a base portion and a plurality of protrusions, The base portion is located in a region of the internal space on the first outer surface side, the plurality of protrusions protrude from the base portion toward the second outer surface along a first direction from the first outer surface toward the second outer surface, The light source is located on the first outer surface side of the base portion, a plurality of gaps between the plurality of protrusions are adjacent to the second opening; the drive portion is located between the plurality of protrusions and the second outer surface in the internal space, A light irradiation device arranged with the first outer surface facing downward, and air passing from the external space through the second opening, the internal space and the third opening in that order, and discharged to the external space.

2. The light irradiation device according to claim 1 , In the first direction, a length of the second opening is equal to or less than a length of the plurality of protrusions, A light irradiation device, wherein the portions of the plurality of gaps on the base portion side are adjacent to the second opening.

3. The light irradiation device according to claim 2, the housing has a first inner surface located on the third outer surface side of the internal space, A light irradiation device, wherein the portions of the plurality of protrusions on the second outer surface side are in contact with the first inner surface.

4. A light irradiation device according to any one of claims 1 to 3, the drive circuit includes one or more electronic components; the one or more electronic components are located between the second opening and the third opening in the first direction; A light irradiation device, wherein the driving unit is located in an area of ​​the internal space closer to the fourth outer surface than the third outer surface, and the one or more electronic components are positioned with the electronic components facing the third outer surface.

5. A light irradiation device according to any one of claims 1 to 3; a conveying unit that conveys a print medium on which light from the first opening is irradiated in a second direction that is a direction from the third outer surface toward the fourth outer surface or a direction from the fourth outer surface toward the third outer surface; a printing unit located on a side of the light irradiation device in a third direction opposite to the second direction, The printing device, wherein the first outer surface faces downward.

6. 6. The printing device according to claim 5, A fixed portion to which the light irradiation device is fixed, the housing is in contact with the heat dissipation member, A printing device, wherein the fixed portion has a seventh outer surface with which the fourth outer surface of the housing is in surface contact.

7. 7. The printing device according to claim 6, a male screw member that fixes the light irradiation device to the fixed portion, The fixed portion has a first through hole portion, the base portion has a screw hole portion on the fourth outer surface side, the housing has a second through-hole portion that opens in the fourth outer surface and is connected to the screw hole portion, The male screw member passes through the first through hole portion and the second through hole portion and is fitted into the screw hole portion.

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