Light source module

Abstract

To provide a light source module of improved light extraction efficiency.SOLUTION: A light source module includes: a plurality of semiconductor light-emitting elements 31 emitting ultraviolet light for sterilizing fluid; a mounting substrate 32 on which the plurality of semiconductor light-emitting elements 31 are directly mounted; a translucent member 35 for penetrating ultraviolet light and separating the plurality of semiconductor light-emitting elements 31 and the mounting substrate 32 from fluid; a liquid material 37 arranged in a part of a space between the plurality of semiconductor light-emitting elements 31 and the mounting substrate 32, and the translucent member 35; and a gas layer 38 arranged in the other part of the space. The liquid material 37 is disposed so as to be brought into contact with the lateral faces of the plurality of semiconductor light-emitting elements 31, and to be brought into non-contact with the mounting substrate 32. The gas layer 38 is formed between the liquid material 37 and the mounting substrate 32. The liquid materials 37 continuously exist including a space at the translucent member 35 side rather than the plurality of semiconductor light-emitting elements 31, and a space between the plurality of semiconductor light-emitting elements 31.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a light source module.

Background Art

[0002] There is known a sterilization device that sterilizes bacteria and viruses in running water by irradiating ultraviolet light. A mercury lamp has been widely used as a light source for ultraviolet light. Since the mercury lamp uses mercury, it has a problem of strong toxicity and a large environmental load. In addition, when a mercury lamp is used, there is also a problem that the sterilization device becomes large. Therefore, the replacement of the mercury lamp with an ultraviolet LED is in progress.

[0003] Patent Document 1 discloses a water sterilization device using an LED that emits ultraviolet light, in which an ultraviolet light irradiation module is disposed near a water inlet provided at one end of a flow path tube through which water flows, and ultraviolet light is emitted from the ultraviolet light irradiation module in the axial direction of the flow path tube.

[0004] The ultraviolet light irradiation module has a light emitting element, a substrate, a housing portion, and a transparent window. The light emitting element is an ultraviolet LED that emits ultraviolet light and is mounted on the substrate. The light emitting element and the substrate are housed in the housing portion. The housing portion is provided with an opening for extracting the ultraviolet light emitted from the light emitting element. The transparent window is installed so as to close the opening of the housing portion. Thereby, the light emitting element is hermetically sealed in the ultraviolet light irradiation module.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the configuration disclosed in Patent Document 1, when the ultraviolet light emitted from the light-emitting element diffuses in the accommodating portion, the amount of ultraviolet light that can be extracted from the opening portion decreases. Therefore, it is preferable to increase the extraction efficiency of the ultraviolet light by directing the ultraviolet light emitted from the light-emitting element toward the opening portion as much as possible.

[0007] However, Patent Document 1 does not mention any method for directing the ultraviolet light emitted from the light-emitting element toward the opening portion.

[0008] The present invention has been made in view of such a background, and aims to provide a light source module in which the extraction efficiency of ultraviolet light is improved.

Means for Solving the Problems

[0009] One aspect of the present invention is a plurality of semiconductor light-emitting elements that emit ultraviolet light for sterilizing a fluid, a mounting substrate on which the plurality of semiconductor light-emitting elements are directly mounted, a light-transmitting member that transmits the ultraviolet light and separates the plurality of semiconductor light-emitting elements, the mounting substrate, and the fluid, a liquid substance disposed in a part of the space between the plurality of semiconductor light-emitting elements, the mounting substrate, and the light-transmitting member, and a gas layer disposed in another part of the space, and includes: the liquid substance is in contact with the element side surface, which is the side surface of the plurality of semiconductor light-emitting elements, and is provided in non-contact with the mounting substrate, the gas layer is formed between the liquid substance and the mounting substrate, in the light source module, the liquid substance continuously exists including the space on the light-transmitting member side of the plurality of semiconductor light-emitting elements and the space between the plurality of semiconductor light-emitting elements.

Effects of the Invention

[0010] In the above light source module, the extraction efficiency of the ultraviolet light emitted from the side surface of the semiconductor light-emitting element can be improved by the liquid substance and the gas layer.

[0011] As described above, according to the above aspect, the extraction efficiency of the ultraviolet light of the light source module can be improved.

Brief Description of the Drawings

[0012]

Figure 1

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Figure 6

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Figure 10

Figure 11

Modes for Carrying Out the Invention

[0013] A liquid substance disposed in a part of the space between the plurality of semiconductor light-emitting elements, the mounting substrate, and the light-transmitting member, and a gas layer disposed in another part of the space, wherein the liquid substance is provided in contact with an element side surface which is a side surface of the plurality of semiconductor light-emitting elements and not in contact with the mounting substrate, the gas layer is formed between the liquid substance and the mounting substrate, and the liquid substance continuously exists including the space on the light-transmitting member side of the plurality of semiconductor light-emitting elements and the space between the plurality of semiconductor light-emitting elements. Thereby, the extraction efficiency of ultraviolet light of the light source module can be improved.

[0014] The liquid substance is filled between the element main surface which is the surface on the light-transmitting member side of the plurality of semiconductor light-emitting elements and the light-transmitting member. Thereby, since reflection of the emitted ultraviolet light on the element main surface can be suppressed, the extraction efficiency of ultraviolet light can be improved.

[0015] The liquid substance is provided in contact with the entire surface formed by the light-transmitting member in the space between the plurality of semiconductor light-emitting elements, the mounting substrate, and the light-transmitting member. Thereby, reflection of the emitted ultraviolet light on the element main surface can be further suppressed, and thus the extraction efficiency of ultraviolet light can be further improved.

[0016] The liquid substance is provided in contact with the side surface of the active layer constituting the plurality of semiconductor light-emitting elements. Thereby, since reflection of the ultraviolet light emitted from the side surface of the active layer on the element side surface can be suppressed, the extraction efficiency of ultraviolet light can be improved.

[0017] A part of the gas layer is located between the parts of the element side surfaces of the adjacent semiconductor light-emitting elements that are in contact with the liquid substance among the adjacent semiconductor light-emitting elements of the plurality of semiconductor light-emitting elements. According to this, a boundary between the liquid substance and the gas layer is formed between the adjacent semiconductor light-emitting elements. The boundary functions as a reflector due to the refractive index difference between the liquid substance and the gas layer. Therefore, since a part of the ultraviolet light output from the element side surface of the semiconductor light-emitting element can be reflected at the boundary and made to travel toward the light-transmitting member side, the extraction efficiency of ultraviolet light can be improved.

[0018] The distance between the plurality of semiconductor light-emitting elements is set to be equal to or less than twice the thickness of each of the plurality of semiconductor light-emitting elements. As a result, the liquid substance is easily kept in a state of continuously existing including the space on the light-transmitting member side and the space between the semiconductor light-emitting elements than the plurality of semiconductor light-emitting elements.

[0019] For example, the thickness of each of the plurality of semiconductor light-emitting elements is 400 μm or more. For example, the liquid substance is a fluorine-based inert liquid.

[0020] (Embodiment 1) 1. Outline of the configuration of the fluid sterilization device 1 FIG. 1 is a cross-sectional view showing the configuration of the fluid sterilization device 1 in the present embodiment, and is a cross-section in a plane including the axis of the fluid sterilization device 1. FIG. 2 is an exploded view of the fluid sterilization device 1 in the present embodiment. FIG. 3 is a cross-sectional view showing the configuration of the light source module 30 in the present embodiment. As shown in FIGS. 1 and 2, the fluid sterilization device 1 of the present embodiment includes a housing 10, a flow path tube 20, a light source module 30, a spacer 40, and a plate 50. Further, as shown in FIGS. 2 and 3, the light source module 30 includes a semiconductor light-emitting element 31 (LED chip), a mounting substrate 32, a seal member 33, a light source case 34, and a light-transmitting member 35.

[0021] The fluid sterilization device 1 of the present embodiment is a device that allows fluid to flow inside a flow path tube 20 and a spacer 40, and irradiates the fluid with ultraviolet light emitted from a light source module 30 to sterilize it. The internal spaces of the flow path tube 20 and the spacer 40 are a flow path space 70 (a space through which the fluid flows during sterilization and is an area irradiated with ultraviolet light). The fluid to be sterilized can be any liquid such as water, oil, alcohol, etc. As long as it has fluidity, it may be in a state where a solid is mixed with the liquid. In this specification, a mixture of a liquid and a solid that has fluidity is also included in the fluid. In the present embodiment, water is used as the fluid to be sterilized. Although the fluid sterilization device 1 of the present embodiment is substantially cylindrical, it may have any shape as long as it can allow fluid to flow, for example, it may be cylindrical such as a rectangular tube shape.

[0022] 2. Details of each component of the fluid sterilization device 1 Next, each component of the fluid sterilization device 1 will be described in detail.

[0023] 2-1. Housing 10 As shown in FIGS. 1 and 2, the housing 10 is cylindrical, an inlet 11 is provided at one end face in the axial direction, and an outlet 12 is provided on the side surface of the cylinder that constitutes the housing 10 near the other end face. The material of the housing 10 is, for example, black PP (polypropylene). Inside the housing 10, a plate 50, a flow path tube 20, and a spacer 40 are coaxially arranged in order from the inlet 11 side.

[0024] The other end face of the housing 10 is open. A thread 13 is provided on the inner peripheral surface of the cylinder near the other end face. The end face of the housing 10 on the thread 13 side is sealed by the light source module 30. The light source module 30 is fitted into the housing 10 and screwed by the thread 13.

[0025] An O-ring 60 is provided between the housing 10 and the plate 50, between the plate 50 and the flow path pipe 20, and between the flow path pipe 20 and the spacer 40, preventing water from leaking between the respective members. The water flowing in from the inlet 11 is irradiated with ultraviolet light emitted from the light source module 30 in the process of sequentially passing through the plate 50, the flow path pipe 20, and the spacer 40, and is discharged from the outlet 12. Note that the positions of the inlet 11 and the outlet 12 may be arbitrary, and their positions may be swapped.

[0026] 2-2. Flow Path Pipe 20 The flow path pipe 20 is composed of a cylindrical member, and the internal space of the cylindrical member serves as the flow path space. In the present embodiment, as shown in FIG. 1, the flow path pipe 20 is cylindrical and has a transparent pipe 21 and a reflector 22 provided in contact with the outer peripheral surface of the transparent pipe 21. The outer peripheral surface of the reflector 22 is in contact with the inner peripheral surface of the housing 10. The reflector 22 has a high reflectance of ultraviolet light and can efficiently irradiate the water flowing through the flow path pipe 20 with ultraviolet light by reflecting the ultraviolet light on the side surface of the flow path pipe 20. Note that the extending direction of the central axis 20a of the flow path pipe 20 is defined as the axial direction Y.

[0027] The transparent pipe 21 is a cylindrical pipe made of quartz, and water to be sterilized flows inside the pipe. The material of the transparent pipe 21 is not limited to quartz, and any material that transmits ultraviolet light and has a low absorption rate may be used. For example, sapphire, ultraviolet-transmitting glass, fluororesin, etc. may be used. In particular, a material with a small refractive index difference from water is preferable, and quartz in the present embodiment is suitable in this regard. For example, a material with a refractive index of 1.3 to 1.5 is preferable.

[0028] The thickness of the transparent pipe 21 is arbitrary as long as it has a strength to withstand water pressure and ultraviolet light transmittance, for example, 0.4 to 3 mm. A material and thickness with an ultraviolet light transmittance of 80% or more in the case of perpendicular incidence are preferable.

[0029] The inner peripheral surface of the transparent tube 21 is preferably as flat as possible. For example, the RMS (root mean square height) is preferably 1 μm or less. Bacteria are less likely to adhere to the unevenness of the inner peripheral surface, dirt is less likely to adhere to the inner peripheral surface, a decrease in the sterilization efficiency can be suppressed, and the generation of bubbles and the like can also be prevented. By forming a water-repellent film such as a fluororesin on the inner peripheral surface of the transparent tube 21, the inner peripheral surface of the transparent tube 21 can be made to repel water, and dirt can be prevented from adhering to the inner peripheral surface of the transparent tube 21.

[0030] The reflector 22 is provided in contact with the outer peripheral surface of the transparent tube 21. The reflector 22 reflects the ultraviolet light that passes through the transparent tube 21 and travels outward.

[0031] The reflector 22 is formed by winding an unfired PTFE (polytetrafluoroethylene) film around the outer peripheral surface of the transparent tube 21 one to a plurality of times. That is, the reflector 22 is a laminate in which an unfired PTFE film is laminated on the transparent tube 21. The unfired PTFE film is a film such as a sheet or tape obtained by rolling PTFE fine powder without firing. Further, the PTFE fine powder is a white powder in which fine particles of PTFE are aggregated.

[0032] For the PTFE fine powder, for example, the powder for paste extrusion molding (II-1 or II-2) standardized in JIS K 6896:1995 can be used. II-1 satisfies the following characteristics. The apparent density (g / ml) is 0.50 ± 0.15, the moisture content (%) is 0.04 or less, the high-temperature volatile content (%) is 0.1 or less, the melting point (°C) is 327 ± 10, the specific gravity is 2.13 to 2.20, the tensile strength (MPa) is 17.6 or more, and the elongation (%) is 200 or more. The measurement methods of these characteristics are based on JIS K 6896:1995. Further, II-2 has the same characteristics as II-1 except that the specific gravity is 2.18 to 2.28.

[0033] As the PTFE green film, an unfired film manufactured using the powder for paste extrusion standardized in JIS K 6896:1995 and not containing additives can be used. In particular, the PTFE unfired tape standardized in JIS K 6885:2005 can be used. The PTFE unfired tape standardized in JIS K 6885:2005 satisfies the following qualities. The apparent density (g / cm 3 ) is 1.0 or more, the tensile strength (MPa) is 7.0 or more, the elongation (%) is 20 or more, the volatile content reduction (%) is 0.5 or less, and it is nonflammable. The measuring methods for these qualities are based on JIS K 6885:2005.

[0034] Since the PTFE green film is unfired, it has self - fusing properties. Therefore, when the PTFE green film is wound around the transparent tube 21, the gap between the transparent tube 21 and the PTFE green film and the gap between the PTFE green films disappear. Thus, the PTFE green film can be closely adhered and fixed to the transparent tube 21 without using an adhesive or the like, and the reflector 22 can be easily formed.

[0035] A partial air layer may remain in the gap between the transparent tube 21 and the PTFE green film or between the PTFE green films. Even if an air layer remains, there is reflection due to the refractive index difference at the interface with the air layer, and the ultraviolet light transmitted through the air layer is reflected by the PTFE green film. Therefore, it does not have much influence on the ultraviolet light reflectance of the reflector 22. Therefore, when winding the PTFE green film around the transparent tube 21 to form the reflector 22, it is not necessary to wind it tightly so that no air layer remains, and the reflector 22 can be easily formed.

[0036] The reflector 22 has a high reflectivity to ultraviolet light. This is due to the following reasons. First, because PTFE itself is a material with a high ultraviolet light reflectivity. Second, because no gaps are generated between the transparent tube 21 and the unfired PTFE film, and between unfired PTFE films, due to the self-fusing property of the unfired PTFE film. Third, because PTFE fine powder becomes fibrous when shear stress is applied, the particles of the unfired PTFE film are fibrous, and as a result, the density of the particles is high.

[0037] The thickness of the reflector 22 is preferably 0.02 mm or more, and the number of windings of the unfired PTFE film may be set so as to achieve such a thickness. A reflectivity equal to or higher than that of barium sulfate, which is a common material as a reflector, can be achieved. In particular, the thickness of the reflector 22 is preferably 0.2 mm or more. An ultraviolet light reflectivity equal to or higher than that in the case where the flow path tube 20 is made of an 8-mm-thick PTFE bulk can be realized. There is no particular upper limit to the thickness of the reflector 22, but as it gets thicker, the ultraviolet light reflectivity saturates, so it is preferably 2 mm or less. Also, the thickness of the reflector 22 may be made thinner than the thickness of the transparent tube 21. Also, the thickness and width of the unfired PTFE film may be arbitrary, or may be values standardized in JIS K 6885:2005.

[0038] In this embodiment, the flow path tube 20 has the transparent tube 21 and the reflector 22, but the entire flow path tube 20 may be formed in a cylindrical shape of PTFE, SUS, titanium, or polyvinyl chloride. A flow path tube 20 may be a member formed by depositing a fluororesin on the inner peripheral surface or the outer peripheral surface of a cylindrical member formed of these materials.

[0039] O-rings 60 are respectively arranged at both ends of the flow path tube 20. Therefore, it is possible to prevent water from entering between the outer peripheral surface of the transparent tube 21 and the inner peripheral surface of the housing 10, more specifically, between the outer peripheral surface of the transparent tube 21 and the inner peripheral surface of the reflector 22, and between the outer peripheral surface of the reflector 22 and the inner peripheral surface of the housing 10.

[0040] As the reflector 22, in addition to the above, aluminum or the like may be used. For example, the reflector 22 can also be formed by winding a thin film of aluminum around the outer peripheral surface of the transparent tube 21, or by forming a thin film of aluminum on the outer peripheral surface of the transparent tube 21 by vapor deposition or sputtering. In this case, it is desirable that the film thickness of aluminum be 25 μm or more.

[0041] 2-3. Light source module 30 As shown in FIGS. 1, 2, and 3, the light source module 30 is cylindrical, and a thread 36 is provided on the side surface of the cylinder (the side surface of the light source case 34). As shown in FIG. 1, the thread 36 of the light source module 30 corresponds to the thread 13 of the housing 10. The light source module 30 is screwed into the open end face of the housing 10, so that the thread 36 of the light source module 30 and the thread 13 of the housing 10 are fitted together and screwed. The light source module 30 is disposed at one axial end of the flow path tube 20 via a spacer 40.

[0042] The light source module 30 emits ultraviolet light, and the ultraviolet light enters the spacer 40 and the inside of the flow path tube 20 from one end of the spacer 40. Thereby, the fluid flowing through the spacer 40 and the flow path tube 20 can be irradiated with ultraviolet light to sterilize the fluid.

[0043] 2-4. Spacer 40 As shown in FIGS. 1 and 2, the spacer 40 is disposed between the flow path tube 20 and the light source module 30. The spacer 40 is a cylindrical tube made of PTFE and is disposed coaxially with the flow path tube 20. The spacer 40 is provided to increase the irradiation efficiency of ultraviolet light to the fluid flowing through the flow path tube 20 by efficiently reflecting the ultraviolet light having a large angle with respect to the axial direction Y of the flow path tube 20 among the ultraviolet light emitted from the light source module 30.

[0044] 2-5. Plate 50 As shown in FIGS. 1 and 2, the plate 50 is disposed between the inlet 11 of the housing 10 and the flow path pipe 20. The plate 50 is disk-shaped and is disposed coaxially with the flow path pipe 20. The material of the plate 50 is PTFE. By using PTFE with high ultraviolet light reflectivity, the ultraviolet light reaching the end face on the inlet 11 side of the flow path pipe 20 is reflected back into the flow path pipe 20, enhancing the irradiation efficiency of the ultraviolet light on the fluid flowing through the flow path pipe 20. A plurality of through holes are provided in the plate 50. The fluid flowing in from the inlet 11 is dispersed by passing through the plurality of through holes in the plate 50 and then flows into the flow path pipe 20.

[0045] 3. Details of Each Component of the Light Source Module 30 As shown in FIG. 3, the light source module 30 is substantially cylindrical and includes a semiconductor light emitting element 31, a mounting substrate 32, a sealing member 33, a light source case 34, and a light transmissive member 35. Further, as shown in FIG. 4, the light source module 30 includes a liquid substance 37 and a gas layer 38.

[0046] 3-1. Semiconductor Light Emitting Element 31 As shown in FIG. 3, the semiconductor light emitting element 31 is mounted on the bottom surface 322 of the recess 321 of the mounting substrate 32. The semiconductor light emitting element 31 is a bare chip that emits ultraviolet light. The wavelength of the ultraviolet light can be determined according to the fluid flowing through the flow path space 70. In this embodiment, since water is adopted as the fluid, the wavelength of the ultraviolet light is preferably 250 to 285 nm, which is a wavelength with high sterilization efficiency for water. The configuration of the semiconductor light emitting element 31 is not limited, and it may be any of a face-up type, a flip-chip type, and a vertically conductive type. However, in this embodiment, the semiconductor light emitting element 31 adopts a flip-chip type. A plurality of semiconductor light emitting elements 31 are provided, and the number of the semiconductor light emitting elements 31 is not limited as long as it is two or more. In this embodiment, as shown in FIG. 3, three semiconductor light emitting elements 31 are included.

[0047] The semiconductor light-emitting element 31 has a rectangular parallelepiped shape. The surface opposite to the mounting substrate 32 constitutes the element main surface 31a, and all the side surfaces adjacent to the element main surface 31a constitute the element side surfaces 31b. The angle formed by the element main surface 31a and the element side surfaces 31b is in the range of 80 to 100°, preferably 90°, across the entire outer periphery of the element main surface 31a.

[0048] On the surface of the semiconductor light-emitting element 31 on the side of the mounting substrate 32, electrode pads (not shown) are provided. As schematically shown in FIG. 6, an active layer 31c is formed inside the semiconductor light-emitting element 31 between the n-type layer and the p-type layer.

[0049] Inside the semiconductor light-emitting element 31, an element substrate, an n-type layer, the active layer 31c, and a p-type layer are laminated in this order, and ultraviolet light is emitted from the active layer 31c. In the present embodiment, since the semiconductor light-emitting element 31 is a flip-chip type, the element substrate of the semiconductor light-emitting element 31 is located on the surface opposite to the mounting substrate 32, and the n-type layer, the active layer 31c, and the p-type layer are formed on the side of the mounting substrate 32 with respect to the element substrate.

[0050] The thickness of the semiconductor light-emitting element 31 is 100 μm or more, preferably 400 μm or more. In particular, the thickness of the element substrate of the semiconductor light-emitting element 31 is 100 μm or more.

[0051] 3-2. Mounting Substrate 32 The mounting substrate 32 is a substrate on which the semiconductor light-emitting element 31 is mounted. As shown in FIG. 3, the mounting substrate 32 has a bottomed cylindrical shape and has a recess 321 on the side facing the flow path tube 20. The bottom surface 322 of the recess 321 has a planar shape perpendicular to the axial direction Y.

[0052] As shown in FIG. 5, a plurality of semiconductor light-emitting elements 31 are arranged on the bottom surface 322 of the recess 321.

[0053] As shown in FIG. 3, the side wall portion 323 of the recess 321 has an annular shape standing upright in the axial direction Y. As a result, the mounting substrate 32 has a bottomed cylindrical shape, and a cylindrical space is formed inside the recess 321. The upper surface of the side wall portion 323 is flat, and the light-transmitting member 35 is attached thereto.

[0054] A circuit forming member (not shown) electrically connected to the semiconductor light-emitting element 31 is mounted on the mounting substrate 32. The circuit forming member is a drive circuit for causing the semiconductor light-emitting element 31 to emit light, a connector header for connecting the drive circuit and a power cable, and the like. In addition, as other electronic components not shown, a thermistor for measuring the temperature of the mounting substrate, a connector header for connecting the thermistor and a power cable, and the like are provided on the mounting substrate.

[0055] The material of the mounting substrate is not limited, but aluminum is adopted in this embodiment. As the mounting substrate, a glass epoxy substrate such as FR-4 or CEM3, or a flexible substrate made of polyimide or the like may be used. In addition, various processes such as drilling may be performed on the mounting substrate.

[0056] 3-3. Light-transmitting member 35 The light-transmitting member 35 has light-transmitting properties that transmit ultraviolet light, and as shown in FIG. 3, covers the ultraviolet light emission side of the plurality of semiconductor light-emitting elements 31. In this embodiment, the light-transmitting member 35 is in a flat plate shape and is joined to the upper surface of the side wall portion 323 of the mounting substrate 32 by resin or solder. As a result, the inner space of the recess 321 is sealed. And the light-transmitting member 35 is configured to contact the flow path space 70.

[0057] The light-transmitting member 35 functions as a window that transmits ultraviolet light emitted from the semiconductor light-emitting element 31. The ultraviolet light emitted from the plurality of semiconductor light-emitting elements 31 passes through the light-transmitting member 35 and enters the flow path space 70. As a result, the fluid flowing through the flow path space 70 is sterilized by the ultraviolet light emitted from the plurality of semiconductor light-emitting elements 31. The light-transmitting member 35 and the semiconductor light-emitting element 31 are separated by a predetermined distance.

[0058] Note that it is not necessary for the entire upper surface of the light-transmitting member 35 to be in contact with the flow path space 70, but it is preferable for the entire surface to be in contact. Also, the side surface of the light-transmitting member 35 may be in contact with the flow path space 70.

[0059] The light-transmitting member 35 is not limited to a flat plate shape and may be a convex lens type. If it is a convex lens type, the directivity of the ultraviolet light emitted from the semiconductor light-emitting element 31 becomes higher and the directivity angle becomes narrower, so that the ultraviolet light can be irradiated more efficiently to the fluid flowing through the flow path space 70. In particular, when the difference between the refractive index of the material of the light-transmitting member 35 and the refractive index of the fluid flowing through the flow path space 70 is large, it is preferable to use a convex lens type.

[0060] The material of the light-transmitting member 35 can be any material that transmits the ultraviolet light emitted from the semiconductor light-emitting element 31, but a material having a thermal conductivity of 0.25 W / m·K or more is preferable. This is for enhancing the heat dissipation efficiency. For example, sapphire, quartz, borosilicate glass, fluororesin, etc. can be used. In terms of enhancing the heat dissipation efficiency, a material with a high thermal conductivity is preferable, and sapphire is used in this embodiment. Also, the light-transmitting member 35 may be formed of a material having a thermal conductivity higher than that of the mounting substrate 32. Heat conduction from the semiconductor light-emitting element 31 to the light-transmitting member 35 through the inner space of the concave portion 321 can be performed more efficiently, and the heat dissipation efficiency can be improved.

[0061] The thickness of the light-transmitting member 35 is preferably 0.1 mm or more. Since the spread of heat becomes large and the heat dissipation area becomes wide, heat dissipation to the fluid flowing through the flow path space 70 via the light-transmitting member 35 can be performed more efficiently. However, if the light-transmitting member 35 becomes too thick, the thermal resistance increases, so it is preferable to set the area and thickness of the light-transmitting member 35 so as to have appropriate heat dissipation characteristics.

[0062] 3-4. Light source case 34 As shown in FIGS. 2 and 3, the light source case 34 is cylindrical and holds the mounting substrate 32 inside. The material of the light source case 34 is not limited. In this embodiment, it is PP, but it may be SUS or the like instead. An opening 34b for transmitting ultraviolet light from the semiconductor light emitting element 31 is provided on the upper surface of the light source case 34 (the surface on the spacer 40 side). Inside the light source case 34, the mounting substrate 32 is arranged such that the opening 34b and the light transmitting member 35 overlap in the axial direction Y. In this embodiment, the upper surface of the light transmitting member 35 is arranged to be flush with the bottom surface of the opening 34b.

[0063] A plurality of convex portions 34a are provided on the outer upper surface of the light source case 34. The convex portions 34a are in contact with the spacer 40. The convex portions 34a create a gap 34c between the upper surface of the light source case 34 and the spacer 40, allowing the fluid that has flowed through the flow path space 70 and reached the inside of the spacer 40 to flow to the discharge port 12 through the gap 34c. The inside of the spacer 40 and the gap 34c are also part of the flow path space 70.

[0064] A thread 36 is provided on the outer peripheral surface of the light source case 34. The thread 36 corresponds to the thread 13 provided on the inner peripheral surface of the housing 10. The light source module 30 fitted into the housing 10 is screwed in by engaging the thread 36 of the light source module 30 with the thread 13 of the housing 10. Note that the light source module 30 may be fixed to the housing 10 by a method other than screwing.

[0065] 3-5. Seal member 33 The seal member 33 is a caulking material formed to fill the gap between the mounting substrate 32 and the light source case 34. The seal member 33 is a polymer material having waterproof properties such as urethane resin, silicone resin, or epoxy resin. The side surface of the light source case 34 and circuit forming members such as the drive circuit of the mounting substrate 32 are covered by the seal member 33, preventing the electronic components mounted on the mounting substrate 32 from coming into contact with water. Note that the upper surface of the light transmitting member 35 is not covered by the seal member 33 and is in contact with the flow path space 70.

[0066] Note that heat conductive particles or heat conductive fibers may be mixed into the seal member 33. By imparting high heat conductivity to the seal member 33, heat from the semiconductor light emitting element 31 is likely to be dispersed through the seal member 33, and heat dissipation performance can be enhanced. In particular, it is preferable that the light source case 34 is also made of a material with high heat conductivity such as metal, and both the seal member 33 and the light source case 34 are made of materials with high heat conductivity.

[0067] Since the light source case 34 is in contact with the flow path space 70, the light source case 34 is in direct contact with the fluid flowing through the flow path space 70, and heat can be dissipated from the seal member 33 through the light source case 34 to the fluid flowing through the flow path space 70. Therefore, heat dissipation performance can be further enhanced. The seal member 33 may be brought into contact with the flow path space 70 to dissipate heat from the seal member 33 to the fluid flowing through the flow path space 70.

[0068] 3-6. Liquid substance 37 The liquid substance 37 is filled in the inner space of the recess 321 of the mounting substrate 32 (the space sealed by the light transmissive member 35). As shown in FIG. 4, the liquid substance 37 has a main facing portion 37a and a sub-facing portion 37b. The main facing portion 37a is the portion filled in the region of the liquid substance 37 where the light transmissive member 35 and the element main surface 31a face each other. Therefore, the liquid substance 37 is in contact with the light transmissive member 35 and the element main surface 31a of the semiconductor light emitting element 31.

[0069] The sub-facing portion 37b is the portion filled in the region where the side wall portion 323 of the recess 321 and the element side surface 31b of the semiconductor light emitting element 31 face each other, and the region where the element side surfaces 31b of adjacent semiconductor light emitting elements 31 face each other. The sub-facing portion 37b is filled in a region closer to the element side surface 31b and closer to the light transmissive member 35. Therefore, the liquid substance 37 is in contact with the side wall portion 323 of the recess 321 and the element side surface 31b of the semiconductor light emitting element 31.

[0070] The sub-facing portion 37b is filled up to the region facing the side surface of the active layer 31c of the semiconductor light emitting element 31. That is, the side surface of the active layer 31c of the semiconductor light emitting element 31 faces the liquid substance 37.

[0071] The liquid substance 37 is liquid at normal temperature and pressure. The liquid substance 37 is an inert compound, and can be, for example, at least one selected from the group consisting of fluorine-based inert liquids, silicon compounds, phosphate compounds, and the like.

[0072] As an example of the liquid substance 37, a fluorine-based inert liquid is preferably a fluorocarbon compound which is a polymer having a CF bond. The number of carbon atoms in the fluorocarbon compound is 1.9 times or less the number of fluorine atoms in the fluorocarbon compound. The fluorocarbon compound is, for example, perfluoropolyether (PFPE), hydrofluoroether (HFE), and the like.

[0073] 3 - 7. Gas layer 38 The gas layer 38 is formed in the inner space (the space sealed by the light-transmitting member 35) of the recess 321 of the mounting substrate 32. In the inner space of the recess 321, as described above, the semiconductor light-emitting element 31 and the liquid substance 37 are disposed. Therefore, the gas layer 38 is disposed in at least a part of the region in the inner space of the recess 321 excluding the region where the semiconductor light-emitting element 31 and the liquid substance 37 are disposed.

[0074] Specifically, the gas layer 38 is formed in the region of the inner space of the recess 321 where the side wall portion 323 of the recess 321 and the element side surface 31b of the semiconductor light-emitting element 31 face each other, in the region closer to the side wall portion 323 of the recess 321 and closer to the bottom surface 322 of the recess 321, and in the region of the inner space of the recess 321 where the element side surfaces 31b of adjacent semiconductor light-emitting elements 31 face each other, in the region closer to the intermediate position between the element side surfaces 31b of the semiconductor light-emitting elements 31 and closer to the bottom surface 322 of the recess 321.

[0075] That is, the gas layer 38 is formed in the region of the inner space of the recess 321 where the side wall portion 323 of the recess 321 and the element side surface 31b of the semiconductor light-emitting element 31 face each other, and in the region of the inner space of the recess 321 where the element side surfaces 31b of adjacent semiconductor light-emitting elements 31 face each other, excluding the sub-opposing portion 37b of the liquid substance 37. Therefore, the gas layer 38 is in contact with the sub-opposing portion 37b of the liquid substance 37.

[0076] The gas layer 38 is formed by including at least one selected from the group such as air, nitrogen, carbon dioxide, etc. The refractive index of the gas layer 38 is smaller than the refractive index of the liquid substance 37. In the present embodiment, the gas layer 38 is formed of air, and the refractive index of air is 1.0.

[0077] 4. Details of the liquid substance 37 The liquid substance 37 includes at least one selected from the group such as fluoride compounds, silicon compounds, phosphate compounds, etc. The viscosity of the liquid substance 37 is 0.01 to 50 Pa·s, preferably 0.1 to 50 Pa·s, and more preferably 1 to 50 Pa·s.

[0078] The contact angle θ1 (shown in FIG. 5) of the liquid substance 37 with respect to the main element surface 31a at a temperature of 25°C is 15° to 25°, preferably 27° to 23°, and more preferably 20°. Due to these, the main facing portion 37a of the liquid substance 37 is held by capillary action. Also, the contact angle θ2 (shown in FIG. 6) of the liquid substance 37 with respect to the side element surface 31b at a temperature of 25°C is 15° to 25°, preferably 27° to 23°, and more preferably 20°. Thereby, the sub-facing portion 37b of the liquid substance 37 is held by capillary action.

[0079] In particular, the arithmetic mean roughness Ra of the main element surface 31a and the side element surface 31b of the semiconductor light-emitting element 31 is 0.1 to 100000 nm. Also from this, the main facing portion 37a and the sub-facing portion 37b of the liquid substance 37 are held by capillary action. Furthermore, the semiconductor light-emitting element 31 is formed in a shape without chips such as notches or dents over the entire outer periphery of the main element surface 31a at the boundary between the main element surface 31a and the side element surface 31b. Therefore, the main facing portion 37a and the sub-facing portion 37b of the liquid substance 37 are held.

[0080] At locations where the semiconductor light-emitting elements 31 are adjacent to each other, the distance between the semiconductor light-emitting elements 31 is set such that the sub-opposing portion 37b is connected in an arch shape between one element side surface 31b side and the other element side surface 31b side. A gas layer 38 is formed below the arch-shaped sub-opposing portion 37b.

[0081] The boiling point of the liquid substance 37 is 150°C or higher, preferably 200°C or higher. The junction temperature Tj of the semiconductor light-emitting element 31 during operation is set to be 150°C or lower, preferably 100°C or lower. In particular, the boiling point of the liquid substance 37 is 50°C or higher, preferably 100°C or higher, than the junction temperature Tj of the semiconductor light-emitting element 31 during operation. Therefore, even if the temperature of the semiconductor light-emitting element 31 rises, vaporization of the liquid substance 37 can be prevented, and the state in which the main opposing portion 37a and the sub-opposing portion 37b are held by capillary action can be maintained.

[0082] The liquid substance 37 has a transmittance of ultraviolet light with a wavelength of 280 nm of 50% or higher, preferably 80% or higher. Further, the refractive index of the liquid substance 37 is closer to the refractive index of the light-transmitting member 35 than the refractive index of air. In this embodiment, the refractive index of the liquid substance 37 is preferably larger than the refractive index of air and equal to or less than the refractive index of the light-transmitting member 35. When the liquid substance 37 is a fluorocarbon compound, the refractive index of the fluorocarbon compound is, for example, 1.2 or more and 1.6 or less.

[0083] 5. Boundary Shape between Liquid Substance 37 and Gas Layer 38 The boundary shape between the liquid substance 37 and the gas layer 38 will be described with reference to FIGS. 5 and 6. In this embodiment, the liquid substance 37 forms the main opposing portion 37a and the sub-opposing portion 37b.

[0084] The shape of the boundary between the liquid substance 37 and the gas layer 38 depends on the viscosity of the liquid substance 37 and the contact angles θ1 and θ2. In this embodiment, at the boundary, the liquid substance 37 has a predetermined angle with respect to the element side surface 31b of the semiconductor light-emitting element 31. The predetermined angle depends on the contact angle θ2 of the liquid substance 37 with respect to the element side surface 31b and the contact angle of the liquid substance 37 with respect to the light-transmitting member 35. For example, the predetermined angle has a minimum value of the contact angle θ2 of the liquid substance 37 with respect to the element side surface 31b or the contact angle of the liquid substance 37 with respect to the light-transmitting member 35, and a maximum value of 45°.

[0085] And the boundary functions as a reflector due to the refractive index difference between the liquid substance 37 and the gas layer 38. That is, a reflector having a predetermined angle is formed on the element side surface 31b of the semiconductor light-emitting element 31. The reflectance at the boundary with respect to ultraviolet light having the emission wavelength is, for example, 50 to 100%.

[0086] The angle of the reflector (the boundary between the liquid substance 37 and the gas layer 38) is preferably equal to or greater than the critical angle of the liquid substance 37. This is because the reflector undergoes total reflection. For example, when a fluorocarbon compound having a refractive index of 1.2 or more and 1.6 or less is used as the liquid substance 37, the critical angle of the liquid substance 37 is about 45°. Therefore, by setting the distance between the semiconductor light-emitting elements 31 to be equal to or less than twice the thickness of the semiconductor light-emitting element 31, it is preferable to set the critical angle of the liquid substance 37 to 45° to 90°.

[0087] 6. Path of Ultraviolet Light The path of the ultraviolet light emitted from the semiconductor light-emitting element 31 will be described with reference to FIG. 6. The ultraviolet light emitted from the active layer 31c of the semiconductor light-emitting element 31 is output from the element main surface 31a of the semiconductor light-emitting element 31. The main facing portion 37a of the liquid substance 37 is filled in the region where the element main surface 31a of the semiconductor light-emitting element 31 and the light-transmitting member 35 face each other. Therefore, in the direction perpendicular to the element main surface 31a, the light-transmitting member 35 is disposed via the liquid substance 37. The emitted ultraviolet light is incident on the light-transmitting member 35 from the element main surface 31a via the liquid substance 37, and is output to the outside from the light-transmitting member 35.

[0088] Here, a liquid substance 37 is in contact with the main element surface 31a, and the liquid substance 37 is in contact with the light-transmitting member 35. Therefore, the emitted ultraviolet light is suppressed from being reflected at the main element surface 31a and is output from the light-transmitting member 35.

[0089] The ultraviolet light emitted from the active layer 31c of the semiconductor light-emitting element 31 is also output from the side surface 31b of the semiconductor light-emitting element 31. In a region where the side surface 31b of the semiconductor light-emitting element 31 and the side wall portion 323 of the recess 321 face each other, a sub-opposing portion 37b of the liquid substance 37 is filled. The emitted ultraviolet light is output from the light-transmitting member 35 through the sub-opposing portion 37b of the liquid substance 37 from the side surface 31b.

[0090] Here, the liquid substance 37 is in contact with the side surface 31b of the element, and the liquid substance 37 is in contact with the light-transmitting member 35. Therefore, the emitted ultraviolet light is suppressed from being reflected at the side surface 31b of the element and is output from the light-transmitting member 35.

[0091] Furthermore, a part of the ultraviolet light output from the side surface 31b of the element is output toward the boundary between the sub-opposing portion 37b of the liquid substance 37 and the gas layer 38.

[0092] At the boundary between the liquid substance 37 and the gas layer 38, the ultraviolet light of the emission wavelength is reflected. Therefore, a part of the ultraviolet light output from the side surface 31b of the element is reflected at the boundary and travels toward the light-transmitting member 35 side. Then, it is output from the light-transmitting member 35 to the outside.

[0093] 7. Manufacturing method of the light source module 30 The manufacturing method of the light source module 30 will be described with reference to FIGS. 5 and 7. In step S1 shown in FIG. 7, each semiconductor light-emitting element 31 is joined to the bottom surface 322 of the recess 321 of the mounting substrate 32.

[0094] Subsequently, in step S2, the liquid substance 37 is dropped onto the element main surface 31a of each semiconductor light-emitting element 31. At this time, as shown in FIG. 5, due to surface tension, the liquid substance 37 stays on the element main surface 31a of the semiconductor light-emitting element 31. The volume of the liquid substance 37 to be dropped is approximately the same as the total volume of the main facing portion 37a and the sub-facing portion 37b. Specifically, the total volume of the liquid substance 37 to be dropped is slightly more than the total volume of the main facing portion 37a and the sub-facing portion 37b. And the total volume of the liquid substance 37 to be dropped is sufficiently less than the total volume of the main facing portion 37a, the sub-facing portion 37b, and the gas layer 38.

[0095] As described above, at a temperature of 25°C, the contact angle θ1 of the liquid substance 37 dropped on the element main surface 31a is 15° to 25°, preferably 27° to 23°, and more preferably 20°. Therefore, on the element main surface 31a, the liquid substance 37 stays on the element main surface 31a in a state with a thin thickness. For convenience of illustration, in FIG. 5, the contact angle θ1 and the thickness of the liquid substance 37 are exaggerated too much in the drawing.

[0096] Subsequently, in step S3 shown in FIG. 7, as indicated by an arrow P1 in FIG. 5, the light-transmitting member 35 is covered and joined to the mounting substrate 32. At this time, as the element main surface 31a approaches the light-transmitting member 35, the liquid substance 37 dropped on the element main surface 31a contacts the light-transmitting member 35 and then gradually moves toward the element side surface 31b side. The liquid substance 37 that has moved to the element side surface 31b side is in a state where the sub-facing portion 37b is held due to the capillary action between the element side surface 31b and the side wall portion 323 of the concave portion 321. In this way, the light source module 30 shown in FIG. 1 is completed.

[0097] Particularly, at a temperature of 25°C, since the contact angle θ1 of the liquid substance 37 dropped onto the main element surface 31a is within the above angle range, the main facing portion 37a can maintain the state of being held in the region of the facing distance H1. Further, since the contact angle θ2 of the liquid substance 37 with respect to the side element surface 31b at a temperature of 25°C is within the above angle range, the sub-facing portion 37b can maintain the state of being held in the region of the facing distance H2. For convenience of illustration, in FIG. 6, the facing distances H1 and H2 are exaggeratedly illustrated.

[0098] 8. Operational Effects Next, the operational effects of the light source module 30 of the present embodiment will be described in detail. According to the light emitting device of the present embodiment, in the space between the plurality of semiconductor light emitting elements 31, the mounting substrate 32, and the light transmissive member 35, the liquid substance 37 is provided in contact with the side element surfaces 31b of the plurality of semiconductor light emitting elements 31, covers the plurality of semiconductor light emitting elements 31, but does not cover the mounting substrate 32, and a gas layer 38 is interposed between the liquid substance 37 and the mounting substrate 32, and the liquid substance 37 continuously exists including the side of the main element surface 31a of the plurality of semiconductor light emitting elements 31 and between the plurality of semiconductor light emitting elements 31.

[0099] Accordingly, the extraction efficiency of the ultraviolet light radiated from the side element surfaces 31b can be improved by the liquid substance 37 and the gas layer 38. Therefore, the extraction efficiency of the ultraviolet light can be improved for the entire light source module 30.

[0100] The liquid substance 37 is filled between the main element surfaces 31a of the plurality of semiconductor light emitting elements 31 and the light transmissive member 35. Thereby, it is possible to suppress the reflected light of the emitted ultraviolet light on the main element surface 31a, so that the extraction efficiency of the ultraviolet light can be improved.

[0101] The liquid substance 37 is provided in contact with the entire surface formed by the light transmissive member 35 in the space between the plurality of semiconductor light emitting elements 31, the mounting substrate 32, and the light transmissive member 35. Thereby, it is possible to further suppress the reflected light of the emitted ultraviolet light on the main element surface 31a, so that the extraction efficiency of the ultraviolet light can be further improved.

[0102] The liquid substance 37 is provided in contact with the side surfaces of the active layers 31c that constitute the plurality of semiconductor light-emitting elements 31. As a result, it is possible to suppress the reflection of the ultraviolet light emitted from the side surfaces of the active layers 31c at the element side surfaces 31b, and thus improve the extraction efficiency of the ultraviolet light.

[0103] A part of the gas layer 38 is located between adjacent semiconductor light-emitting elements 31, between the portions of the element side surfaces 31b of the adjacent semiconductor light-emitting elements 31 that are in contact with the liquid substance 37. According to this, a boundary between the liquid substance 37 and the gas layer 38 is formed between the adjacent semiconductor light-emitting elements 31. The boundary functions as a reflector due to the refractive index difference between the liquid substance 37 and the gas layer 38. Therefore, a part of the ultraviolet light output from the element side surface 31b of the semiconductor light-emitting element 31 can be reflected at the boundary and made to travel toward the light-transmitting member 35 side, so that the extraction efficiency of the ultraviolet light can be improved.

[0104] In the present embodiment, the interval between the plurality of semiconductor light-emitting elements 31 is set to be equal to or less than twice the thickness of each of the plurality of semiconductor light-emitting elements 31. As a result, the liquid substance 37 is easily maintained in a state of continuously existing including the space on the light-transmitting member 35 side and the space between the semiconductor light-emitting elements 31 with respect to the plurality of semiconductor light-emitting elements 31.

[0105] For example, the thickness of each of the plurality of semiconductor light-emitting elements 31 is 400 μm or more. For example, the liquid substance 37 is a fluorine-based inert liquid.

[0106] Further, in the present embodiment, the liquid substance 37 that is liquid at normal temperature and normal pressure is filled in the region where the element main surface 31a and the light-transmitting member 35 face each other to form the main facing portion 37a, and is filled in the region closer to the element side surface 31b and closer to the light-transmitting member 35 among the regions where the element side surface 31b and the side wall portion 323 of the concave portion 321 face each other to form the sub-facing portion 37b.

[0107] Furthermore, in a region where the side wall portion 323 of the concave portion 321 and the element side surface 31b of the semiconductor light emitting element 31 face each other, a gas layer 38 is formed in a region closer to the side wall portion 323 of the concave portion 321 and closer to the bottom surface 322 of the concave portion 321. Thereby, it is possible to prevent a decrease in the extraction efficiency of the ultraviolet light emitted from the element main surface 31a, and it is possible to improve the extraction efficiency of the ultraviolet light emitted from the element side surface 31b. Therefore, it is possible to improve the extraction efficiency of the ultraviolet light for the entire light source module 30.

[0108] Also, in the present embodiment, the main facing portion 37a and the sub-facing portion 37b of the liquid material 37 are held by capillary action. Thereby, the holding force of the main facing portion 37a and the sub-facing portion 37b can be improved, further preventing the outflow of the liquid material 37, and further improving the extraction efficiency of the ultraviolet light for the entire light source module 30.

[0109] Also, in the present embodiment, the facing distance H2 in the sub-facing portion 37b is longer than the facing distance H1 in the main facing portion 37a. Thereby, the holding force of the main facing portion 37a due to capillary action can be further increased to further prevent the outflow of the liquid material 37, and it is possible to further improve the extraction efficiency of the ultraviolet light for the entire light source module 30.

[0110] Also, in the present embodiment, the facing distance H1 in the main facing portion 37a is 0.1 to 500 μm, and the facing distance H2 in the sub-facing portion 37b is 0.1 to 500 μm. Thereby, capillary action for the main facing portion 37a and the sub-facing portion 37b can be surely generated to promote the prevention of the outflow of the liquid material 37, and it is possible to further improve the extraction efficiency of the ultraviolet light for the entire light source module 30.

[0111] Also, in the present embodiment, the Ra of the element side surface 31b of the semiconductor light emitting element 31 is 100 μm or less. Thereby, the contact angle of the liquid material 37 with respect to the element side surface 31b decreases and the wettability decreases. As a result, it is possible to promote the holding of the sub-facing portion 37b by capillary action.

[0112] In addition, in the present embodiment, the semiconductor light-emitting element 31 is formed in a shape without a notch at the boundary between the element main surface 31a and the element side surface 31b. Thereby, the holding force of the main facing portion 37a and the sub-facing portion 37b can be improved, and the outflow of the liquid substance 37 can be further prevented.

[0113] In addition, in the present embodiment, the element side surface 31b of the semiconductor light-emitting element 31 and the side wall portion 323 of the concave portion 321 are formed parallel to each other. Thereby, the holding force of the main facing portion 37a and the sub-facing portion 37b can be improved, and the outflow of the liquid substance 37 can be prevented.

[0114] In addition, in the present embodiment, the side surface of the active layer 31c of the semiconductor light-emitting element 31 faces the sub-facing portion 37b of the liquid substance 37. Thereby, compared with the case where the side surface of the active layer 31c that generates ultraviolet light faces the gas layer 38, the ultraviolet light radiated from the side surface of the active layer 31c is more likely to enter the light-transmitting member 35 through the liquid substance 37 and be output from the light-transmitting member 35, and the extraction efficiency of ultraviolet light of the entire light source module 30 can be further improved.

[0115] In the present embodiment, as described above, in order to hold the main facing portion 37a and the sub-facing portion 37b, the contact angle θ1 of the liquid substance 37 with respect to the element main surface 31a at a temperature of 25°C is set to 15° to 25°. Thereby, a configuration can be adopted in which the liquid substance 37 in a liquid state is held at normal temperature and normal pressure at the facing portion between the element main surface 31a of the semiconductor light-emitting element 31 and the light-transmitting member 35, and a gas layer 38 is formed in the region facing the element side surface 31b.

[0116] In the present embodiment, the viscosity of the liquid substance 37 at a temperature of 25°C is set to 0.01 to 50 Ps·s. Thereby, the contact angle θ1 of the liquid substance 37 with respect to the element main surface 31a at a temperature of 25°C can be set within the above range. Further, by setting the arithmetic mean roughness Ra of the element main surface 31a to 0.1 to 100000 nm, the contact angle θ1 of the liquid substance 37 with respect to the element main surface 31a at a temperature of 25°C can be set within the above range.

[0117] In this embodiment, the liquid substance 37 is disposed in contact with at least a part of the element side surface 31b of the semiconductor light-emitting element 31 in the inner space of the recess 321 of the mounting substrate 32, and the contact angle θ2 of the liquid substance 37 with respect to the element side surface 31b at a temperature of 25°C is set to 15° to 25°. Thereby, the liquid substance 37 can be held in contact with at least a part of the element side surface 31b of the semiconductor light-emitting element 31, and a gas layer 38 can be formed in the region facing the element side surface 31b. Further, by setting the arithmetic mean roughness Ra of the element side surface 31b to 0.1 to 100,000 nm, the contact angle θ2 of the liquid substance 37 with respect to the element side surface 31b at a temperature of 25°C can be set within the above range.

[0118] In this embodiment, the boiling point of the liquid substance 37 is set to 150°C or higher. The junction temperature of the semiconductor light-emitting element 31 during operation is configured to be 150°C or lower. Therefore, even when the temperature of the semiconductor light-emitting element 31 rises during operation, the liquid substance 37 can be held at a desired position.

[0119] In this embodiment, since the transmittance of ultraviolet light having the emission wavelength of the liquid substance 37 is 50% or more, the light extraction efficiency of ultraviolet light can be increased when the liquid substance 37 is disposed. Further, by using a fluoride compound as the liquid substance 37, the refractive index difference between the semiconductor light-emitting element 31 and the liquid substance 37 and the refractive index difference between the light-transmitting member 35 and the liquid substance 37 can be reduced. Therefore, the light extraction efficiency of ultraviolet light can be increased.

[0120] In the above embodiment, the flow path tube 20 is composed of the transparent tube 21 and the reflector 22, but alternatively, it can also be composed of a metal tube. For example, the metal tube is a SUS tube or a Cu tube. The flow path tube 20 can also employ a metal tube plated with a material having a relatively low reflectivity of ultraviolet light on the inner wall.

[0121] In this configuration, the reflectivity of ultraviolet light in the flow path tube 20 is relatively low. However, since the ultraviolet light emitted from the light source module 30 is concentrated within the flow path space 70, even if the flow path tube 20 is made of a material with a relatively low reflectivity, the decrease in the utilization rate of ultraviolet light can be relatively small. Moreover, the flow path tube 20 can be easily fabricated, and cost reduction can be achieved.

[0122] (Embodiment 2) 1. Outline of the Configuration of the Fluid Sterilizing Device 2 FIG. 8 is a diagram schematically showing the configuration of the fluid sterilizing device 2 in the present embodiment. As shown in FIG. 8, the fluid sterilizing device 2 in the present embodiment includes a flow path tube 100 and a light source unit 110. Further, the light source unit 110 includes a semiconductor light emitting element 141, a column portion 120, and a housing portion 130.

[0123] The fluid sterilizing device 2 in the present embodiment is a device that flows a fluid from the inlet 101 of the flow path tube 100 into the flow path space inside the flow path tube 100, irradiates the fluid with ultraviolet light from the light source unit 110 to sterilize the fluid, and discharges the sterilized fluid from the outlet 102. The fluid to be sterilized may be a gas or a liquid, and may be a mixture of a gas and a liquid, a mixture of a gas and a powdery solid, etc., as long as it has fluidity. In the case of a liquid, for example, water, oil, alcohol, a solution using these as solvents, etc.

[0124] 2. Details of Each Component of the Fluid Sterilizing Device 2 Next, each component of the fluid sterilizing device 2 will be described in detail.

[0125] 2-1. Configuration of the Flow Path Tube 100 The flow path tube 100 is cylindrical and has a cylindrical space inside. This space is the flow path space through which the fluid to be sterilized flows. The material of the flow path tube 100 is a metal such as stainless steel, titanium, aluminum, iron, etc., a resin material such as polyvinyl chloride, polyethylene, or PTFE (polytetrafluoroethylene), or a glass such as quartz glass.

[0126] Stainless steel, titanium, iron, and polyvinyl chloride are materials with a high ultraviolet light absorption rate and a low ultraviolet light reflectance rate compared to materials with a high ultraviolet light reflectance rate such as aluminum and PTFE (polytetrafluoroethylene). Stainless steel and titanium are materials with high corrosion resistance to seawater. Glass includes, for example, quartz glass, soda-lime glass, borosilicate glass, lead glass, etc., and is a material that is transparent to ultraviolet light and has a low ultraviolet light reflectance rate. In the case of a material with a low ultraviolet light reflectance rate as the material of the flow path tube 100, for example, the ultraviolet light reflectance rate on the surface in contact with the fluid to be sterilized is 35% or less.

[0127] One light source unit 110 is provided at each of both ends of the flow path tube 100. Further, an inlet 101 is provided on the side wall at one end side (left side in FIG. 8) in the axial direction of the flow path tube 100, and an outlet 102 is provided on the side wall at the other end side (right side in FIG. 8). Hereinafter, the end of the flow path tube 100 on the inlet 101 side will be referred to as the first end, and the end of the flow path tube 100 on the outlet 102 side will be referred to as the second end.

[0128] Of the light source units 110 arranged at both ends of the flow path tube 100, the light source unit arranged closer to the inlet 101 is the first light source unit 110A, and the light source unit arranged closer to the outlet is the second light source unit 110B. Hereinafter, the first light source unit 110A and the second light source unit 110B will be simply referred to as the light source unit 110 without distinguishing their names.

[0129] FIG. 9(a) is a diagram showing the position of the inlet 101, and FIG. 9(b) is a diagram showing the position of the outlet 102. FIGS. 9(a) and 9(b) are cross-sectional views of a cross-section cut along a plane perpendicular to the central axis of the flow path tube 100, viewed from the first end side toward the second end side.

[0130] As shown in Fig. 9(a), the inlet 101 is arranged such that the inflow direction of the fluid flowing in from the inlet 101 is offset with respect to the center O of the flow path tube 100. That is, the central axis L1 of the inlet 101 is displaced so as not to pass through the center O of the flow path tube 100. By offsetting the position of the inlet 101 in this way, a spiral flow can be formed in the flow path space within the flow path tube 100 as shown in Fig. 10. The tangential direction of the spiral flow on the central axis L1 of the inlet 101 is the direction of the central axis L1 of the inlet 101.

[0131] As shown in Fig. 9(b), the outlet 102 is also arranged such that the outflow direction is offset with respect to the center O of the flow path tube 100. That is, the central axis L2 of the outlet 102 is displaced so as not to pass through the center O of the flow path tube 100. As a result, a spiral flow can be maintained also on the outlet 102 side, and the tangential direction of the spiral flow on the central axis L2 of the outlet 102 is the direction of the central axis L2 of the outlet 102.

[0132] 2-2. Configuration of the light source unit 110 The light source unit 110 has a column part 120, a storage part 130, and a semiconductor light emitting element 141. The storage part 130 houses the semiconductor light emitting element 141. Hereinafter, the light source unit 110 provided on the first end side will be described, but the light source unit 110 provided on the second end side has the same configuration.

[0133] As shown in Fig. 8, the column part 120 protrudes in the axial direction of the flow path tube 100 from the first end side to the second end side of the flow path tube 100, and has a frustum-shaped portion. The central axis of the column part 120 coincides with the central axis of the flow path tube 100. That is, the central axis of the column part 120 is arranged coaxially with the central axis of the flow path tube 100.

[0134] The inclination angle (angle with respect to the bottom surface) of the side surface of the frustum is, for example, 30 to 70°. The end on the large diameter side of the column part 120 is connected to the first end of the flow path tube 100, and the end on the small diameter side is connected to the storage part 130.

[0135] The shape of the column portion 120 is not limited to a frustum of a cone, and any shape may be used as long as it becomes thinner toward the second end side. A stepwise thinning shape may be used, but a continuously thinning shape is preferred. For example, a frustum of a pyramid may be used. However, a frustum of a cone is preferred for forming a spiral flow. Also, the entire column portion 120 does not have to be a frustum of a cone, and a part may be a frustum of a cone while the other part is a cylinder. For example, as shown in FIG. 8, the tip side portion of the column portion 120 connected to the storage portion 130 may be cylindrical, and the base side portion connected to the first end of the flow path tube 100 may be frustum-shaped.

[0136] As shown in FIG. 11, the storage portion 130 that houses the semiconductor light emitting element 141 has a glass plate 132, a pedestal portion 133, and a mounting substrate 135.

[0137] The pedestal portion 133 is a bottomed cylindrical member with an open tip surface, and the bottom surface is connected to the tip of the column portion 120. The central axis of the pedestal portion 133 coincides with the central axis of the column portion 120. That is, the central axis of the pedestal portion 133 is arranged coaxially with the central axis of the column portion 120. As described above, the central axis of the column portion 120 is arranged coaxially with the central axis of the flow path tube 100. Therefore, the central axis of the pedestal portion 133 is also arranged coaxially with the central axis of the flow path tube 100.

[0138] In the internal space of the pedestal portion 133, the mounting substrate 135 is arranged at the bottom, and the semiconductor light emitting element 141 is mounted on the mounting substrate 135. A glass plate 132 is provided on the tip surface of the pedestal portion 133 to seal the internal space of the pedestal portion 133. The glass plate 132 is a material that transmits ultraviolet light from the semiconductor light emitting element 141, and is, for example, quartz or sapphire. By providing a photocatalytic film that transmits ultraviolet light on the surface of the glass plate 132, it is possible to suppress the growth of germs on the glass plate 132 or prevent contamination by organic substances. The glass plate 132 is not limited to a flat plate, and may be lens-shaped. For example, a TIR lens, a fly-eye lens, a Fresnel lens, etc. may be used.

[0139] The pedestal portion 133 is formed so as to extend radially outward from the tip of the column portion 120 over the entire circumference of the tip of the column portion 120. That is, the outer diameter of the pedestal portion 133 is larger than the outer diameter of the tip of the column portion 120. Therefore, the bottom surface of the pedestal portion 133 is exposed to the flow path space except for the region connected to the column portion 120.

[0140] A peripheral wall 136 protruding toward the first end side is formed at the outer edge portion of the bottom surface of the pedestal portion 133. As a result, a recessed portion 134 that is recessed more than the peripheral wall 136 is formed in the portion of the bottom surface of the pedestal portion 133 surrounded by the peripheral wall 136. The recessed portion 134 is provided to retain fluid as much as possible near the bottom surface of the pedestal portion 133. The pedestal portion 133 can be cooled by the fluid staying near the bottom surface of the pedestal portion 133. That is, the heat-generating semiconductor light-emitting element 141 can be cooled via the pedestal portion 133.

[0141] In the present embodiment, the peripheral wall 136 is provided over the entire circumference of the bottom surface of the pedestal portion 133, but it may be provided only on a part of the bottom surface of the pedestal portion 133. By providing the peripheral wall 136 only on a part of the bottom surface of the pedestal portion 133, the formation of an air pocket in the recessed portion 134 can be suppressed and the cooling efficiency can be improved.

[0142] The peripheral wall 136 is preferably provided outside the semiconductor light-emitting element 141 when viewed from the central axis direction of the flow path tube 100. That is, when viewed from the central axis direction of the flow path tube 100, it is preferable that the recessed portion 134 is located at a position overlapping the semiconductor light-emitting element 141. The pedestal portion 133 can be cooled more efficiently by the fluid staying near the bottom surface of the pedestal portion 133. That is, the heat-generating semiconductor light-emitting element 141 can be cooled more efficiently via the pedestal portion 133.

[0143] In the present embodiment, the pedestal portion 133 is a bottomed cylindrical member, but any shaped member may be used as long as it is bottomed cylindrical. For example, it may be a bottomed square cylindrical (polygonal box-shaped) member. However, from the viewpoint of generating a spiral flow, it is preferable to be bottomed cylindrical as in the present embodiment.

[0144] The materials of the column part 120 and the pedestal part 133 are preferably metal materials with high thermal conductivity such as aluminum. Titanium may be used as the material of the column part 120 and the pedestal part 133, and the surface may be oxidized to form a photocatalyst film. According to this, it is possible to suppress the propagation of various bacteria in the column part 120 and the pedestal part 133.

[0145] The semiconductor light-emitting element 141 is directly mounted on the mounting substrate 135. A plurality of semiconductor light-emitting elements 141 may be mounted on one mounting substrate 135, and three are mounted in FIGS. 8 and 11.

[0146] The semiconductor light-emitting element 141 is a light-emitting element that emits ultraviolet light. The wavelength of the ultraviolet light is preferably 250 to 285 nm, which is a wavelength with high sterilization efficiency. The configuration of the semiconductor light-emitting element 141 is not limited, and any of a face-up type, a flip-chip type, and a through-conduction type may be used.

[0147] The mounting substrate 135 is a substrate on which the semiconductor light-emitting element 141 is mounted. In the present embodiment, the mounting substrate 135 is formed of aluminum. The mounting substrate 135 may be a glass epoxy substrate such as FR-4 or CEM3, or a flexible substrate made of polyimide or the like.

[0148] As shown in FIG. 11, the mounting surface of the mounting substrate 135 on which the semiconductor light-emitting element 141 is mounted is formed in a planar shape orthogonal to the central axis of the pedestal part 133. In the present embodiment, on the mounting surface of the mounting substrate 135, the three semiconductor light-emitting elements 141 are arranged such that the side surfaces of adjacent semiconductor light-emitting elements 141 abut against each other.

[0149] On the mounting substrate 135, a circuit forming member (not shown) electrically connected to the semiconductor light emitting element 141 is mounted. The circuit forming member is a drive circuit for causing the semiconductor light emitting element 141 to emit light, a connector header for connecting the drive circuit and the power cable, and the like. As other electronic components (not shown), a thermistor for measuring the temperature of the mounting substrate 135, a connector header for connecting the thermistor to the power cable, and the like are provided on the mounting substrate 135.

[0150] As shown in FIG. 11, a liquid substance 137 and a gas layer 138 are enclosed in the storage portion 130. The liquid substance 137 and the gas layer 138 are filled in the inner space of the storage portion 130 (the space sealed by the glass plate 132). The detailed configurations of the liquid substance 137 and the gas layer 138, and the boundary shape between the liquid substance 137 and the gas layer 138 are the same as the detailed configurations of the liquid substance 37 and the gas layer 38, and the boundary shape between the liquid substance 37 and the gas layer 38 in the first embodiment. Therefore, the description of the detailed configurations of the liquid substance 137 and the gas layer 138, and the boundary shape between the liquid substance 137 and the gas layer 138 in the second embodiment is omitted.

[0151] 2-3. Optical axis 144 of the semiconductor light emitting element 141 The optical axis 144 of the semiconductor light emitting element 141 is the axis in the stacking direction of the semiconductor layers for emitting ultraviolet light in the ultraviolet light emitted by the semiconductor light emitting element 141, that is, the axis perpendicular to the main surface of the element substrate on which the semiconductor layers are stacked. The optical axis 144 is, for example, an axis located at the center in the irradiation range of the ultraviolet light of the semiconductor light emitting element 141 having a predetermined light distribution characteristic.

[0152] The optical axis 144 may be a virtual line extending in the direction in which the luminous intensity of the ultraviolet light is maximized from the semiconductor light emitting element 141 in the irradiation range of the ultraviolet light, but is not limited to this depending on the configuration of the semiconductor light emitting element 141. In the present embodiment, the optical axis 144 of the semiconductor light emitting element 141 is on the perpendicular line with respect to the portion of the mounting surface where the semiconductor light emitting element 141 is mounted.

[0153] As described above, the mounting surface of the mounting substrate 135 is formed in a planar shape orthogonal to the central axis of the pedestal portion 133. Therefore, the optical axis 144 of the semiconductor light-emitting element 141 is parallel to the central axis of the pedestal portion 133.

[0154] As described above, the central axis of the pedestal portion 133 is arranged coaxially with the central axis of the flow path tube 100. Therefore, the optical axis 144 of the semiconductor light-emitting element 141 is parallel to the central axis of the flow path tube 100.

[0155] 3. Regarding the fluid flow path Next, the fluid flow path in the flow path space will be described. FIG. 10 is a diagram schematically showing the fluid flow path in the vicinity of the first end of the flow path tube 100. As shown in FIG. 10, the fluid that has entered the flow path space in the flow path tube 100 from the inlet 101 hits the side surface of the frustum-shaped portion of the column portion 120. However, since the side surface is inclined, it is reflected in the axial direction, and a flow toward the storage portion 130 is formed. Therefore, the fluid can be efficiently brought into contact with the storage portion 130, and the cooling efficiency can be improved.

[0156] Since the outer diameter of the pedestal portion 133 is larger than the outer diameter of the tip of the column portion 120, the fluid can be brought into contact with the bottom surface of the pedestal portion 133 (the left side surface in FIG. 10). Therefore, the pedestal portion 133 can be efficiently cooled.

[0157] A peripheral wall 136 is provided on the bottom surface of the pedestal portion 133, and there is a recess 134 surrounded by the peripheral wall 136. Therefore, the fluid tends to stay on the back surface of the pedestal portion 133. Therefore, heat can be efficiently conducted from the bottom surface of the pedestal portion 133 to the fluid, and the cooling efficiency can be improved.

[0158] Since the inlet 101 is offset, as shown in Fig. 10, a flow is formed that swirls around the column part 120. Since the column part 120 is shaped to become thinner from the first end side to the second end side, the fluid flows axially from the first end side to the second end side while swirling around the column part 120. Therefore, a spiral flow is formed in the flow path space. By having a spiral flow, the residence time of the fluid in the flow path space becomes longer, and the irradiation time of ultraviolet light on the fluid becomes longer, so the sterilization efficiency can be improved.

[0159] In the light source part 110 on the outlet 102 side, since the column part 120 is shaped to become thinner from the second end side to the first end side, the fluid flowing from the first end side to the second end side can be reflected in the radial direction of the flow path tube 100 by the column part 120. Therefore, the residence time of the fluid can be lengthened in the vicinity of the storage part 130 on the outlet 102 side, so the storage part 130 can be efficiently cooled.

[0160] 4. Operational effects Similar to the above-described Embodiment 1, a liquid substance 137 and a gas layer 138 are enclosed in the storage part 130, and the boundary shape between the liquid substance 137 and the gas layer 138 is formed in the same manner as in the above-described Embodiment 1. Therefore, the extraction efficiency of ultraviolet light can be improved in the same manner as in the above-described Embodiment 1.

[0161] (Modified form of Embodiment 2) In the fluid sterilization device 2 in Embodiment 2, although the light source part 110 is provided on each of the inlet 101 side and the outlet 102 side, when the flow path tube 100 is short or the like, the light source part 110 may be provided only on the inlet 101 side. In this case, a reflecting member that reflects ultraviolet light is arranged on the end face on the second end side, and the sterilization efficiency can be improved by irradiating the fluid with the reflected light of the ultraviolet light by this reflecting member. Also, the light source part 110 may be provided only on the outlet 102 side. In this case as well, the sterilization efficiency can be improved by providing a reflecting member on the end face on the first end side. As the reflecting member, PTFE (polytetrafluoroethylene), stainless steel, titanium, etc. can be used.

[0162] (Other Modifications) In the above-described embodiment, the sterilization of liquids has been described. However, any fluid can be sterilized, including gases, mixtures of gases and liquids, mixtures of gases and powdered solids, etc.

[0163] The present invention is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

Explanation of Reference Numerals

[0164] 31 Semiconductor light-emitting element 31b Element side surface 32 Mounting substrate 35 Translucent member 37 Liquid substance 38 Gas layer

Claims

1. A plurality of semiconductor light-emitting elements that emit ultraviolet light for sterilizing a fluid; A mounting substrate on which the plurality of semiconductor light-emitting elements are directly mounted; A light-transmitting member that transmits the ultraviolet light and separates the plurality of semiconductor light-emitting elements, the mounting substrate, and the fluid; A liquid substance disposed in a part of the space between the plurality of semiconductor light-emitting elements, the mounting substrate, and the light-transmitting member; A gas layer disposed in another part of the space, comprising: The liquid substance is provided in contact with the main surface of the element, which is the side surface of the plurality of semiconductor light-emitting elements, and is not in contact with the mounting substrate; The gas layer is formed between the liquid substance and the mounting substrate; The liquid substance continuously exists including the space on the light-transmitting member side of the plurality of semiconductor light-emitting elements and the space between the plurality of semiconductor light-emitting elements, a light source module.

2. The liquid substance according to claim 1, wherein the liquid substance is filled between the main surface of the element, which is the surface on the light-transmitting member side of the plurality of semiconductor light-emitting elements, and the light-transmitting member.

3. The liquid substance according to claim 2, wherein the liquid substance is provided in contact with the entire surface formed by the light-transmitting member in the space between the plurality of semiconductor light-emitting elements, the mounting substrate, and the light-transmitting member.

4. The liquid substance according to claim 1, wherein the liquid substance is provided in contact with the side surface of the active layer constituting the plurality of semiconductor light-emitting elements.

5. A part of the gas layer is located between the side surfaces of the adjacent semiconductor light-emitting elements among the plurality of semiconductor light-emitting elements, between the portions in contact with the liquid substance, the light source module according to claim 1.

6. The interval between the plurality of semiconductor light-emitting elements is set to be not more than twice the thickness of each of the plurality of semiconductor light-emitting elements, the light source module according to any one of claims 1 to 5.

7. The thickness of each of the plurality of semiconductor light-emitting elements is 400 μm or more, the light source module according to claim 6.

8. The liquid substance according to any one of claims 1 to 5, wherein the liquid substance is a fluorine-based inert liquid.

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