Light irradiation device and light irradiation method

Abstract

To efficiently irradiate an interior side of a cylindrical container with light.SOLUTION: A light irradiation device 10 includes: a rotating shaft 12; a reflector 14 having a reflection surface 24 extending spirally around the rotating shaft 12; a light source 16 arranged apart from the reflection surface 24 in the axial direction along the rotating shaft 12 and radiating light toward the reflection surface 24 in the axial direction; and a drive mechanism 18 rotating the rotating shaft 12. A light irradiation method includes: inserting the reflector 14 into inside a cylindrical container; rotating the rotating shaft 12 to rotate the reflection surface 24 inside the cylindrical container; and radiating light in the axial direction toward the reflection surface 24 rotating inside the cylindrical container.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a light irradiation device and a light irradiation method. [Background technology]

[0002] A device has been proposed that uses ultraviolet light-emitting diodes (LEDs) to irradiate the inside of a cylindrical container with ultraviolet light, thereby sterilizing the inside of the cylindrical container. For example, a configuration has been proposed in which multiple LEDs are arranged on the surface of an insert that is inserted into the cylindrical container, and the LEDs inserted into the cylindrical container are turned on to irradiate the inside of the cylindrical container with ultraviolet light (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-62903 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned prior art requires a large number of LEDs to illuminate the entire inner surface of the cylindrical container, and a cooling mechanism to cool the large number of LEDs is required inside the insert, making the device configuration complicated.

[0005] The present invention has been made in view of the above problems, and one of its exemplary purposes is to provide a technique for efficiently irradiating the inside of a cylindrical container with light. [Means for solving the problem]

[0006] A light irradiation device according to one embodiment of the present invention comprises a rotation axis, a reflector having a reflective surface extending spirally around the rotation axis, a light source positioned away from the reflective surface in an axial direction along the rotation axis and irradiating light in the axial direction toward the reflective surface, and a drive mechanism for rotating the rotation axis.

[0007] Another aspect of the present invention is a light irradiation method, which includes inserting a reflector having a reflective surface extending spirally around a rotation axis into a cylindrical container, rotating the rotation axis to rotate the reflective surface inside the cylindrical container, and irradiating light in an axial direction along the rotation axis toward the reflective surface rotating inside the cylindrical container.

[0008] According to the present invention, a technique for efficiently irradiating the inner surface of a cylindrical container with light can be provided. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram schematically illustrating a configuration of a light irradiation device according to an embodiment. [Figure 2] FIG. 2 is a plan view schematically illustrating the configuration of a reflector. [Figure 3] FIG. 2 is a plan view schematically illustrating the configuration of a light source. [Figure 4] FIG. 10 is a perspective view schematically illustrating a method of using the light irradiation device. [Figure 5] FIG. 10 is a diagram schematically illustrating an example of an illuminance distribution on a side surface of a cylindrical container. [Figure 6] 1 is a flowchart illustrating an example of a light irradiation method according to an embodiment. [Figure 7] FIG. 10 is a perspective view schematically showing the configuration of a light irradiation device according to a modified example. [Figure 8] FIG. 10 is a perspective view schematically illustrating a method of using the light irradiation device. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the description, the same elements are designated by the same reference numerals, and duplicate explanations will be omitted as appropriate. To facilitate understanding of the description, the dimensional ratios of the components in each drawing do not necessarily correspond to the actual dimensional ratios.

[0011] 1 is a diagram schematically illustrating the configuration of a light irradiation device 10 according to an embodiment. The light irradiation device 10 includes a rotation shaft 12, a reflector 14, a light source 16, and a drive mechanism 18. The light irradiation device 10 is configured to reflect light 20 from the light source 16 on a reflecting surface 24 of the reflector 14 and to irradiate the reflected light 22 in a direction intersecting the rotation shaft 12. The light irradiation device 10 is used, for example, to irradiate the inside of a cylindrical container with light.

[0012] 1, the direction in which rotation shaft 12 extends is the z direction, and the directions perpendicular to rotation shaft 12 are the x direction and y direction. In this specification, the direction in which rotation shaft 12 extends is sometimes referred to as the axial direction, the direction perpendicular to rotation shaft 12 is sometimes referred to as the radial direction, and the direction around rotation shaft 12 is sometimes referred to as the circumferential direction.

[0013] The rotation shaft 12 is a rod extending linearly in the z-direction and supports the reflector 14. The reflector 14 is a plate-like member extending spirally around the rotation shaft 12. The reflector 14 is fixed to the rotation shaft 12. The reflector 14 has a first end 26, a second end 28, and a side portion 30. The first end 26 is provided at one axial end of the reflector 14 and extends radially from the rotation shaft 12. The second end 28 is provided at the other axial end of the reflector 14 and extends radially from the rotation shaft 12. The side portion 30 extends spirally radially away from the rotation shaft 12 and defines the outer shape of the reflector 14. The radial width w from the rotation shaft 12 to the side portion 30 is constant, for example, regardless of the axial position.

[0014] The reflector 14 has a reflecting surface 24 that extends spirally around the rotation axis 12. The reflecting surface 24 extends spirally around the rotation axis 12 from a first end 26 to a second end 28. The reflecting surface 24 is a spiral surface formed between the rotation axis 12 and a side portion 30, and is a surface exposed on the first end 26 side. The reflecting surface 24 is configured to be, for example, a normal spiral surface.

[0015] The angle θ of the normal A of the reflecting surface 24 relative to the axial direction (also referred to as the tilt angle θ) varies depending on the radial distance r from the rotation axis 12. The tilt angle θ of the reflecting surface 24 may be configured to be constant relative to the axial direction at a position where the distance r is fixed. At least a portion of the reflecting surface 24 is configured so that the tilt angle θ of the reflecting surface 24 is 45 degrees or more and 90 degrees or less, for example, in the range of 45 degrees or more and 60 degrees or less. The tilt angle θ of the reflecting surface 24 is configured so that it is 45 degrees or more and 60 degrees or less at the center 24c of the radial width w of the reflecting surface 24. The tilt angle θ of the reflecting surface 24 may be 45 degrees or more or less than 45 degrees near the side portions 30. The tilt angle θ of the reflecting surface 24 near the side portions 30 may be configured to be 40 degrees or more and 50 degrees or less.

[0016] The reflective surface 24 is made of a material that has a high reflectivity for the light 20 from the light source 16. When the light 20 is deep ultraviolet light, the reflective surface 24 is made of aluminum. The reflective surface 24 is configured, for example, to have a highly flat mirror surface. The reflective surface 24 may be configured as a rough surface to diffuse and reflect the light 20. The reflective surface 24 may also be made of a fluorine-based resin material such as polytetrafluoroethylene (PTFE).

[0017] FIG. 2 is a plan view schematically illustrating the configuration of the reflector 14. FIG. 2 illustrates the reflector 14 as viewed in the axial direction from the first end 26 to the second end 28. The reflector 14 is configured so that the angular range φ extending in the circumferential direction from the first end 26 to the second end 28 is equal to or greater than 330 degrees and less than 360 degrees, for example, equal to or greater than 340 degrees and less than 355 degrees. In the illustrated example, the reflector 14 is configured so that the angular range φ is less than 360 degrees and the reflecting surfaces 24 do not overlap in the axial direction. In other words, there is a gap 32 between the first end 26 and the second end 28 where the reflecting surfaces 24 are not provided. Note that the reflector 14 may be configured so that the angular range φ is greater than 360 degrees and the reflecting surfaces 24 overlap in the axial direction near the first end 26 and the second end 28. In this case, there is no gap 32 between the first end 26 and the second end 28 where the reflecting surfaces 24 are not provided.

[0018] Returning to FIG. 1 , the light source 16 is disposed axially away from the reflecting surface 24 and irradiates light 20 in the axial direction toward the reflecting surface 24. The light source 16 is disposed at a position overlapping with the reflecting surface 24 in the axial direction and opposed to the first end 26 of the reflector 14. The light source 16 is attached to a substrate 38. A cooling mechanism 40 for cooling the light source 16 is provided on the substrate 38. The cooling mechanism 40 is, for example, a heat sink. The cooling mechanism 40 may be air-cooled or water-cooled. The substrate 38 is provided with a through-hole 42 through which the rotating shaft 12 is inserted.

[0019] The light source 16 includes an LED 34 and an optical element 36. The LED 34 is a semiconductor light-emitting element that outputs deep ultraviolet light with a wavelength of, for example, approximately 260 nm to 285 nm. The LED 34 may be configured to output ultraviolet light with a wavelength of 285 nm or more, or may be configured to output visible light or infrared light. The optical element 36 distributes the diffused light output from the LED 34 in the axial direction to generate parallel light 20 having a light distribution angle with respect to the axial direction of a predetermined value or less (for example, 10 degrees or less, 5 degrees or less). The optical element 36 is, for example, a reflector having a reflective surface that is a concave curved surface. The optical element 36 may be a lens or a combination of a lens and a reflector.

[0020] 3 is a plan view schematically showing the configuration of the light source 16. The light source 16 includes a plurality of LEDs 34a, 34b, 34c, and 34d, and a plurality of optical elements 36a, 36b, 36c, and 36d. The plurality of LEDs 34a to 34d are arranged side by side around the rotation axis 12. In the example shown, four LEDs 34a to 34d are provided at 90-degree intervals around the rotation axis 12. The plurality of optical elements 36a to 36d distribute the light output from each of the plurality of LEDs 34a to 34d in the axial direction to generate parallel light.

[0021] The number of LEDs 34 and optical elements 36 included in the light source 16 is not particularly limited, and more than four LEDs 34 and optical elements 36 may be arranged. For example, six LEDs 34 and optical elements 36 may be arranged at 60-degree intervals. The light source 16 is preferably configured to irradiate the entire reflective surface 24 with light 20. The number of LEDs 34 and optical elements 36 used can be determined depending on the radial and axial sizes of the reflective surface 24. The radial and axial sizes of the reflective surface 24 may also be determined depending on the sizes of the LEDs 34 and optical elements 36 used. The radial width w of the reflective surface 24 is, for example, 0.5 to 3 times the diameter D (or opening diameter D) of the optical element 36 through which light from the LEDs 34 is emitted, for example, 0.8 to 2 times. The overall axial length H of the reflective surface 24 is, for example, 10 to 40 times the diameter D of the optical element 36, for example, 20 to 30 times the diameter D of the optical element 36.

[0022] Returning to FIG. 1 , the drive mechanism 18 rotates the rotation shaft 12 as indicated by the arrow R. The drive mechanism 18 is, for example, an electric motor. The drive mechanism 18 rotates the rotation shaft 12, thereby rotating the reflector 14. The drive mechanism 18 is, for example, disposed on the opposite side of the reflector 14 with the light source 16 in between. The drive mechanism 18 is, for example, fixed with respect to the light source 16 and the substrate 38. The reflector 14, which is rotated by the drive mechanism 18, rotates relative to the fixed light source 16.

[0023] Next, the operation of the light irradiation device 10 will be described. The light irradiation device 10 rotates the spiral reflective surface 24 by driving the drive mechanism 18. The light source 16 irradiates light 20 in the axial direction toward the rotating reflective surface 24. The light 22 reflected by the reflective surface 24 is emitted along a plane intersecting or perpendicular to the axial direction. The axial position at which the light 20 from the light source 16 enters the reflective surface 24 changes from the first end 26 toward the second end 28 as the spiral reflective surface 24 rotates. The axial distance L to the position at which the light 20 enters the reflective surface 24 shown in FIG. 1 changes within the range from the first end 26 to the second end 28. As a result, the light 22 reflected by the reflective surface 24 is scanned in the axial direction within the range from the first end 26 to the second end 28. Therefore, the light irradiation device 10 can irradiate light 22 in a direction intersecting or perpendicular to the axial direction throughout the range from the first end 26 to the second end 28.

[0024] FIG. 4 is a perspective view that schematically illustrates how to use the light irradiation device 10. The light irradiation device 10 can be used to irradiate light onto the inside of a cylindrical container 50. The light irradiation device 10 is inserted into the cylindrical container 50 so that at least a portion of the reflective surface 24 is located inside the cylindrical container 50. The light source 16 can be disposed outside the cylindrical container 50. For ease of understanding, FIG. 4 omits the illustration of the drive mechanism 18 and illustrates only a portion of the cylindrical container 50.

[0025] Fig. 5 is a diagram schematically illustrating an example of an illuminance distribution on a side surface 52 of a cylindrical container 50. Fig. 5 corresponds to a developed view of the side surface 52, with the vertical direction being the axial direction (z direction) and the horizontal direction being the circumferential direction (R direction). Fig. 5 shows the illuminance distribution when the reflecting surface 24 is fixed without rotating, and illustrates a case in which the light source 16 includes four LEDs 34a to 34d. As shown in Fig. 5, light 22 is irradiated onto an area that continuously extends along a straight line 56 that is oblique to the axial and circumferential directions.

[0026] When the reflecting surface 24 is rotated in the circumferential direction (direction R), the illuminance distribution shown in Fig. 5 moves parallel to the circumferential direction (direction R). Therefore, the light irradiation device 10 can irradiate the entire inner side surface 52 of the cylindrical container 50 with light by irradiating the reflecting surface 24 with light from the light source 16 while rotating the reflecting surface 24.

[0027] The light irradiation device 10 can also irradiate the light 20 onto the inner bottom surface 54 of the cylindrical container 50 through the gap 32 between the first end 26 and the second end 28. When the reflecting surface 24 is rotated in the circumferential direction (direction R), the circumferential position of the gap 32 changes. Therefore, the light irradiation device 10 can irradiate the entire inner bottom surface 54 of the cylindrical container 50 with light through the gap 32 between the first end 26 and the second end 28 by irradiating the reflecting surface 24 with light from the light source 16 while rotating the reflecting surface 24.

[0028] 6 is a flowchart showing an example of a light irradiation method according to an embodiment. First, a reflector 14 having a reflective surface 24 extending spirally around a rotation axis 12 is inserted into a cylindrical container 50 (S10). Next, the rotation axis 12 is rotated to rotate the reflective surface 24 inside the cylindrical container 50 (S12), and light 20 is irradiated in the axial direction toward the reflective surface 24 rotating inside the cylindrical container 50 (S14). As a result, light 22 is irradiated onto the entire side surface 52 and bottom surface 54 of the cylindrical container 50. The rotation of the reflective surface 24 and the irradiation of light 20 onto the reflective surface 24 continue until irradiation is complete (N in S16). When irradiation is complete (Y in S16), the reflector 14 is pulled out and removed from the inside of the cylindrical container 50 (S18).

[0029] According to this embodiment, by irradiating the rotating spiral reflective surface 24 with light 20, it is possible to irradiate the entire inside of the cylindrical container 50 into which the reflective surface 24 is inserted with light 22. For example, by setting the inclination angle θ of at least a portion of the reflective surface 24 to be between 45 degrees and 60 degrees, the light reflected by the reflective surface 24 can be efficiently irradiated onto the side surface 52 and bottom surface 54 of the cylindrical container 50. When the light 20 is deep ultraviolet light, the entire inside of the cylindrical container 50 can be sterilized by irradiating the deep ultraviolet light onto the entire inside of the cylindrical container 50. The cylindrical container 50 may be a beverage can, a plastic bottle, a paper carton, or the like.

[0030] According to this embodiment, since the reflective surface 24 is inserted inside the cylindrical container 50, the light source 16 can be arranged outside the cylindrical container 50. This eliminates the need to arrange the light source 16 inside the cylindrical container 50, increasing the design freedom of the light source 16. For example, it is no longer necessary to downsize the light source in order to arrange it inside a cylindrical container 50 with a small inner diameter, such as a plastic bottle. By arranging the light source 16 outside the cylindrical container 50, it becomes easier to cool the light source 16, and deterioration due to heat generated by the light source 16 can be suppressed. Furthermore, the thermal impact on the cylindrical container 50 caused by heat generated by the light source 16 can also be suppressed.

[0031] According to this embodiment, it is not necessary to arrange a large number of LEDs in the axial direction because it is sufficient to irradiate light 20 from light source 16 to an area that overlaps with reflecting surface 24 in the axial direction. This makes it possible to limit the number of LEDs included in light source 16, thereby reducing the cost of light irradiation device 10.

[0032] 7 is a diagram schematically illustrating the configuration of a light irradiation device 60 according to a modified example. The light irradiation device 60 includes a rotating shaft 12, a reflector 14, a light source 16, and a drive mechanism 62. In this modified example, the drive mechanism 62 rotates the rotating shaft 12 in the circumferential direction indicated by the arrow R, and moves the rotating shaft 12 in the axial direction indicated by the arrow Z. Below, this modified example will be described, focusing on the differences from the above-described embodiment, and a description of the commonalities will be omitted as appropriate.

[0033] The drive mechanism 62 includes a motor 64 and a linear actuator 66. The motor 64 rotates the rotating shaft 12 in the circumferential direction indicated by arrow R. The linear actuator 66 moves the rotating shaft 12 in the axial direction indicated by arrow Z. The linear actuator 66 is configured to move the rotating shaft 12 and the motor 64 that rotates the rotating shaft 12 in the axial direction.

[0034] Fig. 8 is a perspective view that schematically illustrates how to use the light irradiation device 60. For ease of understanding, Fig. 8 omits illustration of the drive mechanism 62 and illustrates only a part of the cylindrical container 70. The axial length of the cylindrical container 70 in Fig. 8 is greater than the axial length of the reflector 14.

[0035] According to this modification, by moving the reflector 14 in the axial direction while rotating it, it is possible to irradiate light onto the entire side surface 72 of the cylindrical container 70 that is long in the axial direction. Therefore, in this modification as well, it is possible to irradiate light onto the entire side surface 72 and bottom surface 74 of the cylindrical container 70. Furthermore, by adjusting the axial movement range of the reflector 14 according to the size of the cylindrical container 70, it is possible to accommodate multiple types of cylindrical containers 70 with different axial lengths.

[0036] The present invention has been described above based on examples. It will be understood by those skilled in the art that the present invention is not limited to the above-described embodiments, and that various design changes and modifications are possible, and that such modifications are also within the scope of the present invention.

[0037] Several aspects of the present invention will now be described.

[0038] A first aspect of the present invention is a light irradiation device including a rotation shaft, a reflector having a reflective surface extending spirally around the rotation shaft, a light source disposed apart from the reflective surface in an axial direction along the rotation shaft and irradiating light toward the reflective surface in the axial direction, and a drive mechanism for rotating the rotation shaft. According to the first aspect, the reflector is inserted inside a cylindrical container and rotated, and light from the light source is irradiated axially onto the rotating reflective surface, thereby enabling efficient irradiation of light inside the cylindrical container.

[0039] In a second aspect of the present invention, in the light irradiation device according to the first aspect, the drive mechanism moves the rotation shaft in the axial direction. According to the second aspect, by moving the rotation shaft in the axial direction and moving the reflector in the axial direction, light can be efficiently irradiated onto the inside of a cylindrical container having a large axial size.

[0040] A third aspect of the present invention is the light irradiation device according to the first or second aspect, wherein the light source includes a plurality of LEDs arranged in a line around the rotation axis and a plurality of optical elements that distribute light output from each of the plurality of LEDs in the axial direction. According to the third aspect, by arranging a plurality of LEDs around the rotation axis, it is possible to irradiate light over a wide range in the axial direction using a limited number of LEDs. By using optical elements that distribute light in the axial direction, it is possible to efficiently irradiate light onto the inside of a cylindrical container.

[0041] A fourth aspect of the present invention is the light irradiation device according to the third aspect, wherein the axial length of the reflecting surface is 10 to 40 times the diameter of each of the plurality of optical elements. According to the fourth aspect, by setting the axial length of the reflecting surface to be 10 to 40 times the diameter of each of the optical elements, the inclination angle of the reflecting surface can be set so that light is efficiently irradiated onto the inner side surface of the cylindrical container.

[0042] A fifth aspect of the present invention is the light irradiation device according to any one of the first to fourth aspects, wherein the reflecting surface is configured so that an angular range extending in the circumferential direction around the rotation axis is 330 degrees or more and less than 370 degrees. According to the fifth aspect, by setting the angular range over which the reflecting surface is provided to 330 degrees or more, light can be efficiently irradiated over a wide range in the circumferential direction. By setting the angular range over which the reflecting surface is provided to less than 360 degrees, light can also be irradiated to the bottom of a cylindrical container.

[0043] A sixth aspect of the present invention is the light irradiation device according to any one of the first to fifth aspects, wherein at least a portion of the reflecting surface is configured so that the reflection angle of light incident on the reflecting surface in the axial direction is between 45 degrees and 60 degrees. According to the sixth aspect, by setting the reflection angle of light on at least a portion of the reflecting surface to between 45 degrees and 60 degrees, it is possible to efficiently irradiate light onto the inner side surface of the cylindrical container.

[0044] A seventh aspect of the present invention is a light irradiation method comprising: inserting a reflector having a reflective surface extending spirally around a rotation axis into a cylindrical container; rotating the rotation axis to rotate the reflective surface inside the cylindrical container; and irradiating light in an axial direction along the rotation axis toward the reflective surface rotating inside the cylindrical container. According to the seventh aspect, light can be efficiently irradiated onto the inside of the cylindrical container.

[0045] An eighth aspect of the present invention is the light irradiation method according to the seventh aspect, in which light output from a light source arranged outside the cylindrical container is irradiated toward the reflecting surface rotating inside the cylindrical container. According to the eighth aspect, by arranging the light source outside the cylindrical container, it is possible to easily cool the light source and suppress the thermal effect on the cylindrical container caused by heat generated by the light source.

[0046] A ninth aspect of the present invention is the light irradiation method according to the seventh or eighth aspect, further comprising: moving the rotation axis in the axial direction to change the axial position of the reflecting surface inside the cylindrical container. According to the ninth aspect, by moving the reflector in the axial direction, light can be efficiently irradiated onto the inside of a cylindrical container having a large axial size. [Explanation of symbols]

[0047] 10...light irradiation device, 12...rotating shaft, 14...reflector, 16...light source, 18...driving mechanism, 24...reflective surface, 34...LED, 36...optical element, 50...cylindrical container, 52...side, 54...bottom.

Claims

1. A rotation axis; a reflector having a reflective surface extending spirally around the rotation axis; a light source disposed apart from the reflecting surface in an axial direction along the rotation axis and configured to irradiate light toward the reflecting surface in the axial direction; a drive mechanism that rotates the rotation shaft, The light source comprises a plurality of LEDs arranged in a row around the rotation axis, and a plurality of optical elements that distribute the light output from each of the plurality of LEDs in the axial direction, and the light irradiation device is configured so that the light emitted from the plurality of optical elements overlaps with each other on the reflecting surface.

2. The light irradiation device described in Claim 1, wherein the light source is configured to simultaneously irradiate light onto the entire line extending spirally on the reflective surface from the first end to the second end of the reflective surface.

3. A light irradiation device as described in claim 1, wherein the light source is configured to simultaneously irradiate light onto the entire reflective surface.

4. The light irradiation device according to claim 1 , wherein the drive mechanism moves the rotation shaft in the axial direction.

5. The light irradiation device according to claim 4 , wherein the length of the reflecting surface in the axial direction is between 10 and 40 times the diameter of each of the plurality of optical elements.

6. The light irradiation device according to claim 1 , wherein the reflecting surface is configured so that an angular range extending in a circumferential direction around the rotation axis is equal to or greater than 330 degrees and less than 360 degrees.

7. The light irradiation device according to claim 1 , wherein at least a part of the reflecting surface is configured so that a reflection angle of light incident on the reflecting surface in the axial direction is between 45 degrees and 60 degrees.

8. inserting a reflector having a reflective surface extending spirally around a rotation axis into the cylindrical container; rotating the rotation shaft to rotate the reflecting surface inside the cylindrical container; and irradiating light output from a light source disposed outside the cylindrical container toward the reflecting surface rotating inside the cylindrical container in an axial direction along the rotation axis, The light source comprises a plurality of LEDs arranged in a row around the rotation axis, and a plurality of optical elements that distribute the light output from each of the plurality of LEDs in the axial direction, and the light emitted from the plurality of optical elements is configured to overlap with each other on the reflecting surface.

9. The light irradiation method according to claim 8 , further comprising: moving the rotation shaft in the axial direction to change the position of the reflecting surface in the axial direction inside the cylindrical container.

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