Light irradiation device

Abstract

To improve reliability of a light irradiation device.SOLUTION: A light irradiation device 10 comprises: a light-emitting element 12; a light source housing 14 having a light source chamber 28 which houses the light-emitting element 12, and an irradiation opening 30 for allowing light 24 output from the light-emitting element 12 to pass; a window member 16 which has a first face 36 which is arranged for the irradiation opening 30 and faces the light-emitting element 12, a second face 38 on the opposite side of the first face 36, and a side face 40 extending in an axial direction from the first face 36 toward the second face 38; a seal member 18 which is arranged between an inner periphery 32 of the irradiation opening 30 and the side face 40 of the window member 16; a first opposing member 20 facing an outer periphery of the first face 36 of the window member 16; and a second opposing member 22 facing an outer periphery of the second face 38 of the window member 16.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a light irradiation device.

Background Art

[0002] There is known a flowing water sterilization device that irradiates treated water with ultraviolet light for sterilization treatment. For example, a partition wall that defines a retention space for the treated water is provided at the center of the housing, and ultraviolet light emitted from an LED disposed inside the housing passes through a glass plate and irradiates the treated water (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above prior art, since the partition wall is arranged adjacent to the plate glass, the plate glass may always be under stress from the partition wall. In a state where a load stress is continuously applied to the glass plate, even if the stress is lower than the fracture toughness value of the glass plate, cracks may grow slowly in the glass plate, leading to breakage of the glass plate.

[0005] The present invention has been made in view of such problems, and an exemplary object thereof is to provide a technique for suppressing breakage of a window member and improving the reliability of a light irradiation device.

Means for Solving the Problems

[0006] A light irradiation device according to an aspect of the present invention includes a light-emitting element, a light source chamber that houses the light-emitting element, a light source housing having an irradiation opening for passing light output from the light-emitting element, a window member disposed at the irradiation opening and having a first surface facing the light-emitting element, a second surface opposite to the first surface, and a side surface extending axially from the first surface to the second surface, a seal member disposed between an inner peripheral surface of the irradiation opening and the side surface of the window member, a first opposing member facing an outer peripheral portion of the first surface of the window member, and a second opposing member facing an outer peripheral portion of the second surface of the window member.

Advantages of the Invention

[0007] According to the present invention, breakage of the window member can be suppressed, and the reliability of the light irradiation device can be improved.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the description, the same reference numerals are assigned to the same elements, and overlapping descriptions are omitted as appropriate. For the purpose of assisting the understanding of the description, the dimensional ratios of the respective components in each drawing do not necessarily match the actual dimensional ratios.

[0010] (First Embodiment) FIG. 1 is a cross-sectional view schematically showing the configuration of a light irradiation device 10 according to the first embodiment. The light irradiation device 10 includes a light-emitting element 12, a light source housing 14, a window member 16, a seal member 18, a first opposing member 20, and a second opposing member 22.

[0011] The light-emitting element 12 is a semiconductor light-emitting element such as an LED (Light Emitting Diode). The light-emitting element 12 may be, for example, a semiconductor light-emitting element using aluminum gallium nitride (AlGaN), and may be configured to output ultraviolet light. The wavelength of the light 24 output from the light-emitting element 12 is, for example, 200 nm or more and 320 nm or less, and for example, 240 nm or more and 280 nm or less. The light-emitting element 12 can be mounted on the substrate 26.

[0012] In this specification, the optical axis direction of the light 24 output from the light-emitting element 12 may be referred to as the axial direction. The axial direction can be defined, for example, by the direction in which the light-emitting element 12 and the window member 16 face each other, and corresponds to the thickness direction of the window member 16.

[0013] The light source housing 14 has a light source chamber 28 that houses the light-emitting element 12. The light source housing 14 has an irradiation opening 30 for passing the light 24 output from the light-emitting element 12. The irradiation opening 30 is provided in front of the light-emitting element 12 and penetrates the light source housing 14 in the axial direction. The inner peripheral surface 32 that defines the irradiation opening 30 is formed in a cylindrical shape. A recess 34 for holding or locking the seal member 18 is formed on the inner peripheral surface 32 of the irradiation opening 30. The light source housing 14 is made of, for example, a metal material such as stainless steel, copper, or aluminum. The light source housing 14 may be made of a resin material.

[0014] The window member 16 is disposed in the irradiation opening 30. The window member 16 is made of a material that transmits the light 24 output from the light-emitting element 12, and is made of, for example, glass, quartz (SiO2), sapphire (Al2O3), or amorphous fluororesin. The window member 16 has a first surface 36 facing the light-emitting element 12, a second surface 38 opposite to the first surface 36, and a side surface 40 extending from the first surface 36 toward the second surface 38. The first surface 36 and the second surface 38 of the window member 16 are, for example, flat surfaces. The side surface 40 of the window member 16 is, for example, a cylindrical surface. At least one of the first surface 36 and the second surface 38 may be a convex curved surface or a concave curved surface, and may be configured to be a convex lens or a concave lens.

[0015] The window member 16 is configured such that the axial thickness t is relatively large. The thickness t of the window member 16 is, for example, 1 / 2 or more of the diameter w of the window member 16. The thickness t of the window member 16 is, for example, larger than the axial thickness ts of the seal member 18 and is 3 times or more or 5 times or more the thickness ts of the seal member 18. The thickness t of the window member 16 is, for example, 10 mm or more, 15 mm or more, or 20 mm or more.

[0016] The seal member 18 is disposed between the light source housing 14 and the window member 16 and seals the irradiation opening 30. The seal member 18 is disposed between the inner peripheral surface 32 of the irradiation opening 30 and the side surface 40 of the window member 16. The seal member 18 is, for example, a seal ring disposed over the entire circumference of the side surface 40 of the window member 16. The width or thickness of the seal member 18 is, for example, 1 mm or more and 5 mm or less. The seal member 18 is, for example, fitted into a recess 34 formed in the inner peripheral surface 32 of the irradiation opening 30.

[0017] The first opposing member 20 faces the outer peripheral portion of the first surface 36 of the window member 16 and restricts the axial displacement of the window member 16. The first opposing member 20 is disposed in the light source chamber 28. The first opposing member 20 is disposed in a ring shape around the light emitting element 12. The first opposing member 20 is disposed avoiding the position facing the central portion of the first surface 36 of the window member 16. The first opposing member 20 has a first opening 42 that communicates axially with the irradiation opening 30. The opening width w1 of the first opening 42 is slightly smaller than the diameter w of the window member 16. The difference between the opening width w1 of the first opening 42 and the diameter w of the window member 16 is, for example, smaller than the radial thickness of the seal member 18. The edge of the first opening 42 may be chamfered. The first opposing member 20 can be made of a resin material such as silicone resin or fluororesin.

[0018] The second opposing member 22 faces the outer peripheral portion of the second surface 38 of the window member 16 and restricts the axial displacement of the window member 16. The second opposing member 22 is disposed outside the light source housing 14 and attached to the front surface 46 of the light source housing 14. The second opposing member 22 is disposed avoiding the position facing the central portion of the second surface 38 of the window member 16. The second opposing member 22 has a second opening 44 that communicates axially with the irradiation opening 30. The opening width w2 of the second opening 44 is slightly smaller than the diameter w of the window member 16. The difference between the opening width w2 of the second opening 44 and the diameter w of the window member 16 is smaller than, for example, the radial thickness of the seal member 18. The edge of the second opening 44 may be chamfered. The second opposing member 22 can be made of a resin material such as silicone resin or fluororesin.

[0019] The axial distance d from the first opposing member 20 to the second opposing member 22 is larger than the axial thickness t of the window member 16. For example, a clearance d1 is set between the first opposing member 20 and the first surface 36 of the window member 16, and a clearance d2 is set between the second opposing member 22 and the second surface 38 of the window member 16. The magnitude of each of the clearances d1 and d2 is smaller than, for example, the axial thickness ts of the seal member 18. Thereby, the window member 16 can be slightly displaced axially between the first opposing member 20 and the second opposing member 22. Further, even if the window member 16 is displaced axially, the sealing performance by the seal member 18 can be suitably maintained.

[0020] Next, the operation of the light irradiation device 10 will be described. The light emitting element 12 is disposed in the light source chamber 28 and sealed by the light source housing 14, the window member 16, and the seal member 18. The light 24 output from the light emitting element 12 passes through the first opening 42, passes through the window member 16 disposed in the irradiation opening 30, and is irradiated to the outside through the second opening 44. The window member 16 is supported by the seal member 18 disposed on the side surface 40 of the window member 16.

[0021] According to this embodiment, since the sealing member 18 is provided on the side surface 40 of the window member 16, the holding force for holding the window member 16 is applied to the side surface 40 and not to the first surface 36 and the second surface 38. Further, since the window member 16 can be slightly displaced axially between the first opposing member 20 and the second opposing member 22, it is not necessary to receive excessive stress from the first opposing member 20 and the second opposing member 22. As a result, it is possible to suppress the elongation of cracks due to continuous stress being applied to the first surface 36 or the second surface 38 of the window member 16, and it is possible to suppress breakage of the window member 16 due to crack elongation. As a result, the reliability of the light irradiation device 10 can be improved.

[0022] (Second Embodiment) FIG. 2 is a cross-sectional view schematically showing the configuration of the light irradiation device 10A according to the second embodiment. The second embodiment further includes a flow path housing 50, and is configured such that the light 24 output from the light emitting element 12 is irradiated onto the water to be treated flowing inside the flow path housing. Hereinafter, the light irradiation device 10A according to the second embodiment will be described centering on the differences from the above-described first embodiment, and the description of the common points will be omitted as appropriate.

[0023] The light irradiation device 10A includes a light emitting element 12, a light source housing 14, a window member 16, a sealing member 18, a first opposing member 20, a second opposing member 22, and a flow path housing 50. The light emitting element 12, the light source housing 14, the window member 16, the sealing member 18, the first opposing member 20, and the second opposing member 22 are configured in the same manner as in the first embodiment and are disposed inside the flow path housing 50.

[0024] The flow path housing 50 has a first flow port 52, a second flow port 54, and an internal space 56. The internal space 56 is located between the first flow port 52 and the second flow port 54 and communicates with the first flow port 52 and the second flow port 54. The flow path housing 50 houses the water to be treated flowing through the internal space 56. The flow path housing 50 is made of a resin material or a metal material. The flow path housing 50 is made of, for example, a resin material such as polyethylene, polypropylene, or polytetrafluoroethylene.

[0025] In the example shown in FIG. 2, the first flow port 52 is the inlet port and the second flow port 54 is the outlet port. However, the inlet port and the outlet port may be reversed, the second flow port 54 may be the inlet port, and the first flow port 52 may be the outlet port.

[0026] The light-emitting element 12 is configured to output light 24. The light 24 output from the light-emitting element 12 is irradiated toward the water to be treated flowing through the internal space 56. The light source chamber 28 is hermetically sealed by the light source housing 14, the window member 16, and the seal member 18.

[0027] The air pressure of the light source chamber 28 is applied to the first surface 36 of the window member 16, and the water pressure of the internal space 56 is applied to the second surface 38 of the window member 16. Therefore, a force caused by the pressure difference between the air pressure and the water pressure is applied to the window member 16. However, since no seal member is provided on the first surface 36 and the second surface 38 of the window member 16, the force for sandwiching and holding the window member 16 vertically is not applied to the first surface 36 and the second surface 38. As a result, the force applied to the first surface 36 and the second surface 38 of the window member 16 can be reduced, and the elongation of the crack caused by the stress applied to the first surface 36 or the second surface 38 can be suppressed. The window member 16 can be displaced axially by the force caused by the pressure difference, but the axially displaceable range is restricted by the first opposing member 20 or the second opposing member 22. When the window member 16 contacts the first opposing member 20 or the second opposing member 22, the window member 16 receives a force from the first opposing member 20 or the second opposing member 22. The magnitude of the force at this time is caused by the pressure difference and does not include the force for sandwiching and holding the window member 16 vertically. Therefore, also in the present embodiment, the force applied to the window member 16 can be reduced, and the elongation and breakage of the crack in the window member 16 can be suppressed.

[0028] When the window member 16 faces the water to be treated, it is known that the elongation of cracks in the window member 16 is promoted by moisture. According to the present embodiment, since the forces applied to the first surface 36 and the second surface 38 of the window member 16 can be suppressed, even in an environment where the window member 16 is constantly in contact with moisture, the elongation of cracks can be suppressed, and the reliability of the light irradiation device 10A can be improved.

[0029] (Third Embodiment) FIG. 3 is a cross-sectional view schematically showing the configuration of the light irradiation device 10B according to the third embodiment. In the third embodiment, it is different from the second embodiment in that the second opposing member 22B is configured to function as a partition member that defines the treatment flow path 60. Hereinafter, the light irradiation device 10B according to the third embodiment will be described centering on the differences from the above-described second embodiment, and the description of the common points will be omitted as appropriate.

[0030] The light irradiation device 10B includes a light emitting element 12, a light source housing 14, a window member 16, a seal member 18, a first opposing member 20, a second opposing member 22B, and a flow path housing 50. The light emitting element 12, the light source housing 14, the window member 16, the seal member 18, and the first opposing member 20 are configured in the same manner as in the first embodiment and are disposed inside the flow path housing 50. The flow path housing 50 is configured in the same manner as in the second embodiment.

[0031] The second opposing member 22B has a second opening 44, a first communication port 62, a second communication port 64, and an inner surface 66. The second opposing member 22B is disposed between the light source housing 14 and the second flow port 54. The second opening 44 is formed at the lower part of the second opposing member 22B and is provided at a position facing the second surface 38 of the window member 16. The first communication port 62 and the second communication port 64 are formed at the upper part of the second opposing member 22B. The first communication port 62 is provided at a position communicating with the second flow port 54. The second communication port 64 is provided at a position displaced in the radial direction from the first communication port 62 and is provided at a position not communicating with the second flow port 54. The inner surface 66 of the second opposing member 22B is configured as a concave surface that extends spherically from the second opening 44 toward the first communication port 62. The inner surface 66 defines a treatment flow path 60 irradiated with the light 24 output from the light emitting element 12.

[0032] The water to be treated flowing in from the first flow port 52 flows into the treatment flow path 60 inside the second opposing member 22B through the second communication port 64. After the water to be treated flowing through the treatment flow path 60 is irradiated with light 24, it flows out to the outside from the second flow port 54 through the first communication port 62.

[0033] The second opposing member 22B is made of a material with a high reflectivity of light 24, for example, a fluororesin such as polytetrafluoroethylene. By providing the treatment flow path 60 defined by the second opposing member 22B, the light 24 can be reflected by the inner surface 66 of the second opposing member 22B, and the action amount of the light 24 on the water to be treated flowing through the treatment flow path 60 can be improved. Further, by providing the treatment flow path 60, the water to be treated can be guided to the central portion of the treatment flow path 60 where the irradiation amount of the light 24 is relatively large. Thereby, the irradiation performance of the light irradiation device 10B can be improved.

[0034] As described above, the present invention has been described based on the embodiments. It is understood by those skilled in the art that the present invention is not limited to the above-described embodiments, various design changes are possible, various modifications are possible, and such modifications are also within the scope of the present invention.

[0035] Hereinafter, some aspects of the present invention will be described.

[0036] A first aspect of the present invention is a light irradiation device including a light emitting element, a light source chamber that houses the light emitting element, a light source housing having an irradiation opening for passing light output from the light emitting element, a window member disposed at the irradiation opening and having a first surface facing the light emitting element, a second surface opposite to the first surface, and a side surface extending axially from the first surface toward the second surface, a seal member disposed between an inner peripheral surface of the irradiation opening and the side surface of the window member, a first opposing member facing an outer peripheral portion of the first surface of the window member, and a second opposing member facing an outer peripheral portion of the second surface of the window member. According to the first aspect, by disposing the seal member on the side surface of the window member, a structure can be achieved in which no holding force is applied to the first and second surfaces of the window member, and elongation of cracks caused by stress applied to the first or second surface can be suppressed. Further, by disposing opposing members facing each of the first and second surfaces of the window member, detachment of the window member can be prevented. As a result, the reliability of the light irradiation device can be improved.

[0037] A second aspect of the present invention further includes a flow path housing having an inlet and an outlet and housing treated water flowing from the inlet toward the outlet, wherein the light source housing is disposed inside the flow path housing, and the light emitting element outputs light toward the treated water, and is the light irradiation device according to the first aspect. According to the second aspect, a process of irradiating the treated water with light can be performed. When the window member comes into contact with the treated water, elongation of cracks tends to be promoted compared to the case where it does not. According to the second aspect, since a structure can be achieved in which no holding force is applied to the first and second surfaces of the window member, elongation of cracks in the window member can be suppressed even when the window member comes into contact with moisture. As a result, the reliability of the light irradiation device can be improved.

[0038] A third aspect of the present invention is the light irradiation device according to the second aspect, wherein the second opposing member has an opening through which light that has passed through the window member passes, a communication port that communicates with the inlet or the outlet, and a concave surface extending from the opening toward the communication port. According to the third aspect, since the light can be reflected by the concave surface and irradiated onto the treated water, the irradiation ability with respect to the treated water can be improved.

[0039] The fourth aspect of the present invention is the light irradiation device according to any one of the first to third aspects, wherein the axial thickness of the window member is 1 / 2 or more of the diameter of the window member. According to the fourth aspect, by increasing the axial thickness of the window member, the durability of the window member can be improved, and the sealing performance by the seal member provided on the side surface of the window member can be improved.

[0040] The fifth aspect of the present invention is the light irradiation device according to any one of the first to fourth aspects, wherein the axial distance from the first opposing member to the second opposing member is larger than the axial thickness of the window member and smaller than the sum of the thickness of the window member and the axial width of the seal member. According to the fifth aspect, a gap can be provided between the window member and the first opposing member or the second opposing member, and the stress applied to the first surface and the second surface of the window member can be reduced. Further, by reducing the gap between the window member and the first opposing member or the second opposing member, detachment of the window member and the seal member can be prevented.

[0041] The sixth aspect of the present invention is the light irradiation device according to any one of the first to fifth aspects, wherein the window member is made of quartz glass or sapphire, and at least one of the first opposing member and the second opposing member is made of a resin material. According to the sixth aspect, by forming the opposing member of a resin material having lower rigidity than the window member, damage to the window member due to contact between the window member and the opposing member can be suppressed.

Explanation of Reference Numerals

[0042] 10... Light irradiation device, 12... Light emitting element, 14... Light source housing, 16... Window member, 18... Seal member, 20... First opposing member, 22... Second opposing member, 24... Light, 28... Light source chamber, 30... Irradiation opening, 32... Inner peripheral surface, 36... First surface, 38... Second surface, 40... Side surface, 42... First opening, 44... Second opening, 50... Flow path housing, 52... First flow port, 54... Second flow port, 56... Internal space.

Claims

1. A light-emitting element, a light source housing that houses the light-emitting element, and an irradiation opening for passing light output from the light-emitting element, a window member disposed at the irradiation opening and having a first surface facing the light-emitting element, a second surface opposite to the first surface, and a side surface extending in the axial direction from the first surface toward the second surface, a seal member disposed between the inner peripheral surface of the irradiation opening and the side surface of the window member, a first opposing member facing the outer peripheral portion of the first surface of the window member, a second opposing member facing the outer peripheral portion of the second surface of the window member, A light irradiation device.

2. Further comprising a flow path housing having an inlet and an outlet and housing the water to be treated flowing from the inlet toward the outlet, wherein the light source housing is disposed inside the flow path housing, and the light-emitting element outputs light toward the water to be treated. The light irradiation device according to claim 1.

3. The second opposing member has an opening through which the light passing through the window member passes, a communication port communicating with the inlet or the outlet, and a concave surface extending from the opening toward the communication port. The light irradiation device according to claim 2.

4. The axial thickness of the window member is 1 / 2 or more of the diameter of the window member. The light irradiation device according to any one of claims 1 to 3.

5. The axial distance from the first opposing member to the second opposing member is greater than the axial thickness of the window member and less than the sum of the thickness of the window member and the axial width of the seal member. The light irradiation device according to any one of claims 1 to 3.

6. The window member is made of quartz glass or sapphire, and at least one of the first opposing member and the second opposing member is made of a resin material. The light irradiation device according to any one of claims 1 to 3.

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