WO2024202314A1 - Ultraviolet ray irradiation device - Google Patents

Abstract

Provided is an ultraviolet ray irradiation device that offers high ultraviolet ray extraction efficiency.　This ultraviolet ray irradiation device comprises: an excimer lamp having a housing, a light extraction surface provided in a side surface of the housing, a straight tube-shaped light-emitting tube accommodated in the housing, and a first electrode and a second electrode that are spaced apart from each other in a first direction parallel to the tube axis of the light-emitting tube and apply a voltage to the light-emitting tube; and a reflective member that faces toward a central part of the light-emitting tube, has a first reflective surface for reflecting an ultraviolet ray having a component traveling in the first direction, and reflects at least a portion of the ultraviolet ray emitted by the excimer lamp. With respect to the first direction, the first reflective surface of the reflective member is disposed between a first reference point located in the vicinity of a first end of the light-emitting tube and a second reference point located in the vicinity of a second end, the first end being located on the first electrode side, the second end being located on the opposite side to the first end.

Description

Ultraviolet irradiation equipment

The present invention relates to an ultraviolet irradiation device.

　Conventionally, there is known a technology for inactivating bacteria or viruses present in air, for example, by irradiating them with ultraviolet light. Here, "inactivation" is a concept that encompasses killing bacteria or eliminating the infectiousness and toxicity of viruses. In recent years, coupled with the spread of infectious diseases such as COVID-19, interest in hygiene management has increased significantly, and there is a demand for more efficient inactivation processing of bacteria or viruses. Therefore, the applicant has proposed an ultraviolet irradiation device that can be used for applications such as the above-mentioned inactivation (see Patent Document 1 below).

Patent No. 6940033

A known ultraviolet irradiation device has a configuration in which a light source such as an excimer lamp that emits ultraviolet light is disposed inside a housing, as described in the above Patent Document 1. FIG. 15 is an exploded perspective view of the main casing 2a and lid 2b of the housing 2 in the ultraviolet irradiation device 100 according to Patent Document 1. FIG. 15 also shows an X-Y-Z coordinate system in which the axial direction of the light-emitting tube 3 of the excimer lamp is the X direction, and the plane perpendicular to the X direction is the YZ plane. The ultraviolet light emitted from the excimer lamp is extracted to the outside of the housing 2 through a light extraction surface 10 provided on the housing 2, and is irradiated onto the space or object to be irradiated.

The excimer lamp shown in FIG. 15 emits ultraviolet light from the light-emitting tube 3 when a voltage is applied to a pair of electrode blocks (11, 12) that are arranged so as to contact the wall surface of the light-emitting tube 3. At this time, since the ultraviolet light travels in all directions, the ultraviolet light emitted from the excimer lamp includes ultraviolet light that does not travel directly to the light extraction surface 10 provided on the housing 2. From the viewpoint of efficiently irradiating ultraviolet light into the space to be irradiated, it is preferable that more ultraviolet light is extracted from the light extraction surface 10 than the total amount of ultraviolet light emitted by the excimer lamp.

Patent Document 1 proposes reducing the angle of incidence of ultraviolet light on the optical filter 21 in consideration of the characteristics of the optical filter 21 arranged on the light extraction surface 10. More specifically, the electrodes (11, 12) on which the light-emitting tube 3 of the excimer lamp is mounted are provided with tapered surfaces (11b, 12b) that are inclined with respect to the light extraction surface 10. As a result, ultraviolet light incident on the tapered surfaces is reflected towards the light extraction surface 10, and can be incident on the light extraction surface 10 at a small angle of incidence.

In other words, in the configuration shown in FIG. 15, ultraviolet light emitted from the light-emitting tube 3 and incident on the tapered surfaces (11b, 12b) is extracted to the outside of the housing 2 from the light extraction surface 10. However, as described above, ultraviolet light is emitted from the light-emitting tube 3 in all directions, and therefore some ultraviolet light has a component that travels in the axial direction (X direction) of the light-emitting tube 3. The inventor therefore realized that there is room for further improvement in the ultraviolet light extraction efficiency of conventional ultraviolet irradiation devices.

In view of the above circumstances, the present invention aims to provide an ultraviolet irradiation device with high ultraviolet extraction efficiency.

The ultraviolet irradiation device according to the present invention comprises:
A housing and
a light extraction surface provided on a side surface of the housing;
an excimer lamp including a straight arc tube housed in the housing, and a first electrode and a second electrode arranged to apply a voltage to the arc tube and spaced apart from each other in a first direction parallel to a tube axis of the arc tube;
a reflecting member having a first reflecting surface facing a center portion of the arc tube and reflecting ultraviolet light having a component traveling in the first direction, and reflecting at least a portion of the ultraviolet light emitted by the excimer lamp;
The first reflecting surface of the reflecting member is characterized in that, with respect to the first direction, it is arranged between a first reference point located near a first end of the light-emitting tube on the first electrode side and a second reference point located near a second end located opposite the first end.

Here, "vicinity" refers to a position that is a predetermined distance away from the end of the light-emitting tube (the first end or the second end) toward the outside in the first direction. Note that the predetermined distance refers to a distance equivalent to half the distance in the first direction between the end and the electrode closer to the end.

As mentioned above, the ultraviolet light emitted from the excimer lamp includes ultraviolet light that does not travel directly to the light extraction surface provided on the housing. Specifically, this includes ultraviolet light that has a component that travels in a first direction from the light-emitting tube. Ultraviolet light traveling in a first direction from the light-emitting tube is likely to reach the inner wall surface of the housing rather than the light extraction surface. Ultraviolet light that reaches the inner wall surface of the housing in this way is absorbed by the inner wall surface of the housing, and is hardly extracted from the light extraction surface.

In contrast, with the above configuration, ultraviolet light emitted from the excimer lamp and having a component traveling in a first direction is reflected by the first reflecting surface. The ultraviolet light reflected by the first reflecting surface is reflected toward the center of the light-emitting tube in the first direction. In other words, the reflecting member changes the traveling direction of the ultraviolet light incident on the reflecting surface, so that at least a portion of the ultraviolet light traveling toward the inner wall surface of the housing is reflected toward the light extraction surface, and the amount of ultraviolet light extracted from the light extraction surface increases. This improves the ultraviolet light extraction efficiency of the ultraviolet irradiation device.

In addition, by positioning the first reflecting surface between the first reference point and the second reference point, more ultraviolet light can be reflected than when the first reflecting surface is positioned farther away from the light-emitting tube.

The first reflecting surface may be disposed between the first electrode and the first reference point, or between the second electrode and the second reference point.

As mentioned above, in an excimer lamp, ultraviolet rays are generated due to the application of a voltage to a pair of electrodes. More specifically, the application of this voltage generates a discharge plasma inside the light-emitting tube, exciting the atoms or molecules of the light-emitting gas into an excimer state, and ultraviolet rays are emitted when this returns to the ground state. Because the discharge plasma is generated between the first and second electrodes, ultraviolet rays are mainly generated in the space between the pair of electrodes inside the light-emitting tube. Therefore, in order to reflect ultraviolet rays emitted from the center of the light-emitting tube, particularly from the space between the pair of electrodes, it is preferable that the first reflecting surface is positioned on the opposite side of the center of the light-emitting tube from the pair of electrodes, as mentioned above.

The reflecting member may have a plurality of the first reflecting surfaces, and the plurality of first reflecting surfaces may face each other in the first direction.

Ultraviolet rays that have a component traveling in a first direction include ultraviolet rays that travel toward the first end of the light-emitting tube and ultraviolet rays that travel toward the opposite, second end. With the above configuration, both types of ultraviolet rays are reflected, making it possible to extract more ultraviolet rays.

The first reflecting surface may be inclined with respect to the light extraction surface, so that the ultraviolet light incident on the first reflecting surface may be reflected toward the light extraction surface.

Generally, ultraviolet light incident on a reflecting surface is not reflected in its entirety, but rather is absorbed by the reflecting surface to some extent. In view of this, it is preferable that the ultraviolet light irradiation device is configured so that ultraviolet light emitted from the excimer lamp and traveling in a direction different from the light extraction surface is directed toward the light extraction surface with a small number of reflections. In contrast, by tilting the first reflecting surface with respect to the light extraction surface, ultraviolet light incident on the first reflecting surface is reflected toward the light extraction surface. For this reason, the above configuration is preferable because it makes it easier for ultraviolet light reflected by the first reflecting surface to be directed toward the light extraction surface.

The reflecting member may have a second reflecting surface facing the center of the light-emitting tube, which reflects ultraviolet light having a component traveling in a second direction perpendicular to the first direction on a plane parallel to the light extraction surface.

As mentioned above, ultraviolet light is emitted from the light-emitting tube in all directions. With the above configuration, the second reflecting surface reflects a portion of the ultraviolet light having a component traveling in the second direction, changing the direction of travel of the ultraviolet light, so that, for example, at least a portion of the ultraviolet light traveling toward the inner wall surface of the housing is reflected toward the light extraction surface. This increases the amount of ultraviolet light extracted from the light extraction surface, improving the efficiency of extracting ultraviolet light.

The reflecting member may have a plurality of the second reflecting surfaces, and the plurality of second reflecting surfaces may face each other in the second direction.

The second reflecting surface may be inclined with respect to the light extraction surface, so that the ultraviolet light incident on the second reflecting surface may be reflected toward the light extraction surface.

The first reflecting surface may be located between the light emitting tube and the light extraction surface in a third direction perpendicular to the light extraction surface.

In order to prevent ultraviolet light from being incident on the inner wall of the housing or the like and being absorbed at a position between the excimer lamp and the light extraction surface in the third direction, it is preferable that the first reflecting surface is disposed at a position according to the above configuration. The same applies to the second reflecting surface.

The reflecting member may include the first reflecting surface that is positioned away from the light emitting tube in a second direction perpendicular to the first direction on a plane parallel to the light extraction surface when viewed in the first direction.

Ultraviolet rays emitted from the light-emitting tube at a small angle relative to the light extraction surface tend to head toward the inner wall of the housing and are difficult to extract from within the housing. In contrast, with the above configuration, ultraviolet rays that have a component traveling in the first direction and travel at a small angle relative to the light extraction surface can be reflected at a position that is offset from the light-emitting tube in the second direction when viewed in the first direction. This increases the amount of ultraviolet rays reflected toward the light extraction surface, and as a result, more ultraviolet rays are extracted from the light extraction surface.

The reflective member may be made of an insulating material.

As mentioned above, a high-frequency high voltage is applied to the electrodes. For this reason, if the reflective member is conductive, there is a concern that an unintended discharge path may be formed between the reflective member and the electrodes. There is also a concern that if the reflective member is displaced due to an impact from movement, etc., the two may come into contact and cause a short circuit. In view of these concerns, it is preferable that the reflective member be made of an insulating material.

The reflective member may be made of polytetrafluoroethylene.

Polytetrafluoroethylene (PTFE) is characterized by its ease of processing, such as cutting, and can be used to create reflective components in any shape. PTFE is also an ideal material for reflective components because of its insulating properties.

The present invention provides an ultraviolet irradiation device with high ultraviolet extraction efficiency.

1 is a perspective view showing a schematic external view of an embodiment of an ultraviolet irradiation device; FIG. 2 is an exploded perspective view of a main casing and a cover of the housing of the ultraviolet irradiation device shown in FIG. 1 . FIG. 2B is a perspective view of the main casing shown in FIG. 2A with the reflecting member disassembled; FIG. 2 is a perspective view showing a schematic structure of an electrode block. 11 is a plan view illustrating a schematic structure of the reflecting member when viewed from the +Z direction. FIG. 11 is a cross-sectional view showing a schematic arrangement of a reflective member in a housing when viewed in the Y direction. FIG. 4 is a cross-sectional view showing a schematic arrangement of a reflective member in a housing when viewed in the X direction. FIG. 13 is a plan view showing another example of the configuration of the reflecting member. FIG. FIG. 11 is a perspective view showing a schematic appearance of an ultraviolet irradiation device according to a second embodiment. FIG. 8 is an exploded perspective view of the ultraviolet irradiating device shown in FIG. 7 , showing a main casing and a lid. 2 is a perspective view showing a schematic structure of an electrode block, an arc tube, and a reflecting member provided in the ultraviolet irradiation device. FIG. 10 is an exploded perspective view of the electrode block and the reflecting member 4 shown in FIG. 9. FIG. 10 is a cross-sectional view showing a schematic arrangement of a reflective member in a housing when viewed in the Z direction. FIG. 11 is a cross-sectional view showing a schematic arrangement of a reflective member in a housing when viewed in the Y direction. FIG. FIG. 11 is a perspective view showing another configuration example of the reflecting member according to the second embodiment. FIG. 11 is a cross-sectional view showing yet another configuration example of the reflective member according to the second embodiment. 13 is a perspective view of an ultraviolet irradiation device showing another example of the configuration of a reflective member. FIG. FIG. 1 is a perspective view showing a schematic structure of an ultraviolet irradiation device 100 according to Patent Document 1.

[First embodiment]
A first embodiment of an ultraviolet irradiation device according to the present invention will be described with reference to the drawings. Note that the following drawings are schematic illustrations, and the dimensional ratios in the drawings do not necessarily match the actual dimensional ratios. Furthermore, the dimensional ratios between the drawings do not necessarily match.

In the following figures, as in FIG. 15 described above, the explanation will be given with reference to the X-Y-Z coordinate system in which the tube axis direction of the light-emitting tube 3 of the excimer lamp is the X direction, and the plane perpendicular to the X direction is the YZ plane. More specifically, the direction perpendicular to the X direction on a plane parallel to the light extraction surface 10 is the Y direction, and the direction perpendicular to the X and Y directions is the Z direction. The X direction corresponds to the "first direction", the Y direction corresponds to the "second direction", and the Z direction corresponds to the "third direction".

In addition, in the following description, when a positive or negative direction needs to be distinguished, it is described with a positive or negative sign, such as "+X direction" and "-X direction". When a direction is described without distinguishing between positive and negative directions, it is simply described as "X direction". In other words, in this specification, when it is simply described as "X direction", both the "+X direction" and the "-X direction" are included. The same applies to the Y direction and the Z direction.

In addition, in the following figures, the same elements as those described above with reference to FIG. 15 are given the same reference numerals, and their explanations are appropriately simplified.

FIG. 1 is a perspective view showing a schematic external appearance of one embodiment of an ultraviolet irradiation device according to the present invention. FIG. 2A is an exploded perspective view of the main casing 2a and the cover 2b of the housing 2 of the ultraviolet irradiation device 1 in FIG. 1. FIG. 2B is an exploded perspective view of the reflective member 4 (described later) from the main casing 2a in FIG. 2A.

As shown in FIG. 1, the ultraviolet irradiation device 1 has a housing 2 with a light extraction surface 10 formed on the side. Also, as shown in FIGS. 2A and 2B, the housing 2 has a main casing portion 2a and a cover portion 2b, and houses the light-emitting tube 3 of the excimer lamp, electrode blocks (11, 12), and a reflecting member 4. In FIGS. 2A and 2B, the light-emitting tube 3 is hatched with solid lines to make it easier to understand.

In this embodiment, the arc tube 3 of the excimer lamp is made of a dielectric material such as quartz glass, and the arc tube 3 is filled with an emitting gas containing krypton gas and chlorine gas. In this embodiment, the arc tube 3 has a straight tube shape. As an example, in this embodiment, the total length of the arc tube 3 in the X direction is 70 mm. Note that the number of arc tubes 3 housed in the housing 2 is not limited in the present invention.

The electrode blocks 11 and 12 are spaced apart from each other in the X direction and form electrodes for supplying power to each light-emitting tube 3. FIG. 3 is a perspective view showing a schematic structure of the electrode blocks (11, 12). As shown in FIG. 3, the electrode block 11 is configured to have a mounting area 11a on which the light-emitting tube 3 of the excimer lamp is mounted (see also FIG. 2B), and a tapered surface 11b formed at a position spaced apart from the light-emitting tube 3 in the Y direction and inclined with respect to the XY plane. Similarly, the electrode block 12 has a mounting area 12a and a tapered surface 12b. The effect of the tapered surfaces (11b, 12b) will be described later with reference to FIG. 5B. In this embodiment, the electrode block 11 corresponds to the "first electrode" and the electrode block 12 corresponds to the "second electrode."

The electrode blocks (11, 12) are made of a conductive material, preferably a material that is reflective to ultraviolet light L1. As an example, both electrode blocks (11, 12) are made of a metal material such as aluminum, an aluminum alloy, or stainless steel.

As an example, in this embodiment, the distance between the electrode blocks (11, 12) is 6 mm.

By applying a high-frequency high voltage to the electrode blocks (11, 12), ultraviolet light L1 is obtained from the light-emitting tube 3. The light extraction surface 10 is made of a glass material such as quartz glass in order to extract the ultraviolet light L1 emitted from the light-emitting tube 3 to the outside of the housing 2. The light extraction surface 10 may also be made of an opening.

As mentioned above, the light emitting tube 3 contains krypton gas and chlorine gas as light emitting gases. Therefore, ultraviolet light L1 with a main emission wavelength in the range of 200 nm to 240 nm is obtained from the light emitting tube 3. Here, the "main emission wavelength" refers to a wavelength band that shows a light intensity of 40% or more of the highest light intensity (peak intensity) in the emission spectrum.

Ultraviolet rays with wavelengths between 200nm and 240nm have a high protein absorption coefficient, and most of them are absorbed by the surface of human skin (e.g. the stratum corneum). For this reason, ultraviolet rays with wavelengths in this range have the characteristic that they do not easily penetrate deep into the skin, and have an extremely low impact on the human body.

Even excimer lamps that emit ultraviolet light with a main emission wavelength in the range of 200 nm to 240 nm may emit a small amount of ultraviolet light in a wavelength range (240 nm to 300 nm) that may have an adverse effect on the human body. In view of this, in this embodiment, an optical filter 21 that suppresses the transmission of ultraviolet light in the range of 240 nm to 300 nm is disposed on the light extraction surface 10 (see FIG. 2A).

Here, "the optical filter is disposed on the light extraction surface" includes cases where the optical filter is disposed integrally with the light extraction surface, as well as cases where the optical filter is disposed at a position spaced apart from the light extraction surface by several mm to several tens of mm in the Z direction. "Suppressing transmission" refers to lowering the ratio of the light intensity of ultraviolet light having a wavelength of 240 to 300 nm to the light intensity of ultraviolet light having a wavelength of 200 nm to 240 nm among the ultraviolet light that has passed through the optical filter. As an example, the optical filter 21 is composed of a dielectric multilayer film in which a thin layer of silica (SiO ₂ ) and a thin layer of hafnia (HfO ₂ ) are laminated.

The reflective member 4 is made of, for example, polytetrafluoroethylene (PTFE) and has reflective surfaces (4x, 4y) that are reflective to ultraviolet light L1. The reflective member 4 is disposed on the +Z side of the main body casing 2a (see FIG. 2B).

FIG. 4 is a plan view showing a schematic structure of the reflecting member 4 when viewed from the +Z direction. As shown in FIG. 4, the reflecting member 4 has two reflecting surfaces 4x arranged opposite each other in the X direction, and two reflecting surfaces 4y arranged opposite each other in the Y direction. In this embodiment, the reflecting surfaces 4x correspond to the "first reflecting surface" and the reflecting surfaces 4y correspond to the "second reflecting surface."

5A and 5B are cross-sectional views showing the arrangement of the reflective member 4 in the housing 2. FIG. 5A is a drawing when viewed in the Y direction, and FIG. 5B is a drawing when viewed in the X direction. As shown in FIG. 5A and FIG. 5B, the reflective surface (4x, 4y) is disposed between the light-emitting tube 3 and the light extraction surface 10 in the Z direction, and faces the center side of the light-emitting tube 3. In this embodiment, the reflective surface (4x, 4y) is inclined with respect to the light extraction surface 10. The reflective member 4 is sandwiched between the main casing part 2a and the electrode blocks (11, 12), and the reflective surface (4x, 4y) abuts against the electrode blocks (11, 12) (see also FIG. 2A).

More specifically, the reflective surface 4x abuts against the electrode blocks (11, 12) and the light-emitting tube 3 (see FIG. 5A). On the other hand, in this embodiment, the reflective surface 4y abuts against the electrode blocks (11, 12), but the reflective surface 4y may also abut against the electrode blocks (11, 12) and the light-emitting tube 3 (see FIG. 5B). Note that in the present invention, the method of installing the reflective member 4 is not limited, and it is optional whether or not the reflective surfaces (4x, 4y) abut against the electrode blocks (11, 12) or the light-emitting tube 3.

The reflecting surface 4x is located between the first reference point P1 and the second reference point P2 in the X direction (see FIG. 5A). The first reference point P1 is an imaginary point located at a distance d1 in the -X direction from the first end 5a on the -X side of the light-emitting tube 3. The distance d1 corresponds to half the distance d2 between the first end 5a and the electrode block 11. The second reference point P2 is an imaginary point located at a distance d3 in the +X direction from the second end 5b on the +X side of the light-emitting tube 3. The distance d3 corresponds to half the distance d4 between the second end 5b and the electrode block 12.

In this embodiment, as an example, the distances d2 and d4 are both 17 mm. The distances d2 and d4 may be different.

In this embodiment, the -X side reflective surface 4x is located between the first end 5a and the electrode block 11 in the X direction, and the +X side reflective surface 4x is located between the second end 5b and the electrode block 12 in the X direction. As mentioned above, ultraviolet light L1 is mainly generated between the pair of electrode blocks (11, 12), so taking the -X side as an example, it is preferable that the reflective surface 4x is located between the first end 5a and the electrode block 11.

The reflective member 4 is, for example, composed of a sheet-like material. An example of a manufacturing procedure for the reflective member 4 will be described with reference to FIG. 4. First, a substantially rectangular sheet made of a material that is reflective to ultraviolet light L1 is prepared. Then, a typically rectangular area 31 is cut out from the center of the sheet by cutting or other processing to obtain a frame-like sheet. Next, the cutout portion 30 is formed. The area corresponding to the reflective surface (4x, 4y) is then folded toward the -Z side to form the reflective member 4.

The reflective member 4 can be made of a sheet material made of fine particles of a fluororesin material such as polytetrafluoroethylene (PTFE) as described above. PTFE is particularly suitable as it is easy to process, such as by cutting and bending. The reflective member 4 can also be made by forming a reflective film that reflects ultraviolet light L1 on any sheet material. The reflective film is, for example, a coating film of the above-mentioned fluororesin material. In this case, the reflective film forms the reflective surfaces (4x, 4y).

PTFE exhibits diffuse reflectivity with respect to ultraviolet light L1. It is believed that at least a portion of the diffuse light reflected by the reflective surfaces (4x, 4y) exhibiting diffuse reflectivity travels toward the light extraction surface 10, and therefore it is expected that the efficiency of extracting ultraviolet light L1 from the light extraction surface 10 will be improved. In other words, the reflective surfaces (4x, 4y) exhibiting diffuse reflectivity improve the efficiency of extracting ultraviolet light L1 from the light extraction surface 10 even if the alignment of the reflective surfaces (4x, 4y) with respect to the light extraction surface 10 or the light-emitting tube 3 is slightly misaligned. In other words, the reflective surfaces (4x, 4y) exhibiting diffuse reflectivity have the effect of simplifying the alignment of the reflective surfaces (4x, 4y) with respect to the light extraction surface 10 or the light-emitting tube 3.

From the viewpoint of diffusively reflecting ultraviolet light L1 on the reflective surfaces (4x, 4y), the reflective member 4 may be made of silicone resin, or may have a ceramic film containing silica or alumina as a reflective film. In addition, the reflective surfaces (4y, 4z) may be textured to form reflective surfaces that exhibit diffuse reflectivity.

The reflective surfaces (4x, 4y) may be configured to specularly reflect the ultraviolet light L1. As an example, the reflective member 4 may be configured from a sheet material made of a metal such as aluminum. However, from the viewpoint of suppressing the formation of a discharge path between the electrode blocks (11, 12) and the reflective member, it is preferable that the reflective member 4 has insulating properties. From this viewpoint, for example, a dielectric multilayer film that reflects the ultraviolet light L1 may be configured by alternately laminating dielectric films with different refractive indices on any insulating sheet material. In this case, the dielectric multilayer film forms the reflective surfaces (4x, 4y).

Below, we will explain the mode of travel of the ultraviolet light emitted by the light-emitting tube 3 with reference to Figures 5A and 5B.

By arranging the reflective surface 4x between the first reference point P1 and the second reference point P2, ultraviolet light L1 that has a component traveling in the X direction and does not travel directly to the light extraction surface 10 is reflected by the reflective surface 4x (see FIG. 5A). This increases the amount of ultraviolet light L1 traveling toward the light extraction surface 10, improving the extraction efficiency of ultraviolet light L1 from the light extraction surface 10. In addition, from the perspective of reflecting ultraviolet light L1 traveling in both the +X and -X directions, it is preferable that multiple reflective surfaces 4x are arranged facing each other, as shown in FIG. 5A.

Furthermore, by tilting the reflecting surface 4x with respect to the light extraction surface 10, the amount of ultraviolet light L1 reflected by the reflecting surface 4x that travels toward the light extraction surface 10 can be increased. Note that when the optical filter 21 is made of a dielectric multilayer film, it exhibits incidence angle dependency, in which the transmittance of ultraviolet light decreases as the incidence angle increases. For this reason, from the viewpoint of reducing the incidence angle of ultraviolet light on the optical filter 21, it is preferable that the reflecting surface 4x be tilted with respect to the light extraction surface 10.

In addition, by arranging the reflective surface 4x between the light-emitting tube 3 and the light extraction surface 10 in the Z direction, ultraviolet light L1 traveling toward the inner wall of the housing 2 on the +Z side of the light-emitting tube 3 can be reflected by the reflective surface 4x.

As shown in FIG. 5B, the reflective surface 4y reflects ultraviolet light L1 having a component traveling in the Y direction. This improves the efficiency of extracting ultraviolet light L1 from the light extraction surface 10. The same discussion as for the reflective surface 4x can be applied to the fact that the multiple reflective surfaces 4y are arranged facing each other, are inclined with respect to the light extraction surface 10, and are arranged on the +Z side of the light-emitting tube 3.

As mentioned above, the electrode blocks (11, 12) have tapered surfaces (11b, 12b) that are inclined relative to the light extraction surface 10. As shown in FIG. 5B, the electrode block 11 has tapered surface 11b, so that ultraviolet light L2 emitted from the light-emitting tube 3 and incident on tapered surface 11b is reflected toward the light extraction surface 10. A similar discussion can be made about tapered surface 12b of electrode block 12. In this case, the tapered surfaces (11b, 12b) form the reflective surface 4y, and the electrode blocks (11, 12) also serve as the reflective member 4.

[verification]
In the ultraviolet irradiation device 1 having the above-described configuration, the irradiance of the ultraviolet light L1 taken out from the housing 2 was verified, which will be described below.

Example 1
In this verification, the configuration of the first embodiment described above was adopted as Example 1.

The irradiance of ultraviolet light L1 was measured using an illuminometer consisting of an ultraviolet integrating light meter (UIT-250) manufactured by Ushio Inc. and a separate type light receiver (VUV-S172) manufactured by Ushio Inc. that has been calibrated with light having a wavelength of 222 nm. The irradiance was measured at a position 50 mm away from the light extraction surface 10 on the +Z side.

(Comparative Example 1)
As a comparative example 1, the irradiance of the ultraviolet light L1 in the case where the reflecting member 4 was not arranged was verified.
The conditions of Comparative Example 1 were the same as those of Example 1, except that the reflecting member 4 was removed from within the housing 2 .

[Verification results]
The results of the comparison of irradiance obtained in this verification are shown in the following Table 1. In Table 1, the relative values of irradiance are shown with Comparative Example 1 as the standard.

As shown in Table 1, by providing the reflecting member 4 (Example 1), the irradiance of the ultraviolet light extracted from the light extraction surface 10 was approximately 1.2 times that in the absence of the reflecting member 4 (Comparative Example 1).

[Discussion]
The above result is believed to be due to the fact that the reflecting member 4 is disposed and the ultraviolet rays L1 are reflected by the reflecting surfaces (4x, 4y), thereby increasing the amount of ultraviolet rays L1 traveling toward the light extraction surface 10. In other words, it can be understood that the efficiency of extracting ultraviolet rays L1 from the light extraction surface 10 is increased by disposing the reflecting member 4.

In other words, the configuration according to the first embodiment described above makes it possible to realize an ultraviolet irradiation device with high ultraviolet extraction efficiency.

In the first embodiment, the reflecting surfaces (4x, 4y) are inclined with respect to the light extraction surface 10. However, the present invention is not limited to this, and the reflecting surfaces (4x, 4y) may be arranged perpendicular to the light extraction surface 10. Even if the reflecting surfaces (4x, 4y) are not inclined with respect to the light extraction surface 10, it can be understood that the ultraviolet light L1 is reflected by the reflecting surfaces (4x, 4y) and the proportion of ultraviolet light absorbed by, for example, the inner wall of the housing 2, relative to the ultraviolet light emitted from the light-emitting tube 3, is reduced, thereby improving the efficiency of extracting ultraviolet light from the light extraction surface 10.

In addition, in the above, the reflecting member 4 has multiple reflecting surfaces 4x, but the reflecting surface 4x may be a single surface. Even if the reflecting surface 4x is arranged only on the +X side of the light-emitting tube 3, the ultraviolet light L1 is reflected by the reflecting surface 4x, and the amount of ultraviolet light traveling toward the light extraction surface 10 increases, which is presumably the result of improving the ultraviolet light extraction efficiency of the ultraviolet light irradiation device.

Similarly, the reflecting surface 4y may be a single surface. Also, it is optional whether or not the reflecting member 4 has a reflecting surface 4y.

Furthermore, in the above description, the reflective surfaces (4x, 4y) are described as being composed of an integrated frame-shaped reflective member 4. However, as shown in FIG. 6, for example, the reflective surfaces (4x, 4y) may be composed of multiple separate sheet members. FIG. 6 is a plan view showing another example configuration of the reflective member 4. Based on the above verification results, it is presumed that the efficiency of extracting ultraviolet light can be improved even when the reflective member 4 is composed of multiple separate members.

As of the filing date of this application, the American Conference of Governmental Industrial Hygienists (ACGIH) and other organizations have established recommended threshold limit values (TLVs) for the amount of ultraviolet radiation that the human body can be exposed to per day (8 hours). However, as the effects of ultraviolet radiation on the human body have become clearer in recent years, the TLVs have been relaxed for ultraviolet radiation in the wavelength range of 200 nm to 240 nm, for example, where the effects of exposure on the human body are low.

As the TLV is relaxed, it is expected that ultraviolet light will be irradiated at a higher output, and therefore it is believed that a higher output ultraviolet light irradiation device will be required as the TLV is relaxed. In contrast, in the first embodiment, ultraviolet light in the wavelength range of 200 nm to 240 nm that has a low impact on the human body is emitted, while the efficiency of extracting ultraviolet light from the housing 2 is increased. In other words, the configuration described with reference to the first embodiment can meet the demand for higher output ultraviolet light irradiation devices that accompanies the relaxation of the TLV.

[Second embodiment]
Hereinafter, a second embodiment of the ultraviolet irradiating device according to the present invention will be described with reference to FIGS. 7 to 10, focusing on the differences from the first embodiment.

FIG. 7 is a perspective view showing a schematic appearance of an ultraviolet irradiation device 1 according to a second embodiment. FIG. 8 is a perspective view showing the main casing 2a and the cover 2b of the housing 2 of the ultraviolet irradiation device 1 disassembled from FIG. 7. FIG. 9 is a perspective view showing a schematic structure of the electrode block (11, 12), the light emitting tube 3, and the reflecting member 4 provided in the ultraviolet irradiation device 1, and FIG. 10 is a perspective view showing the electrode block (11, 12) and the reflecting member 4 disassembled according to FIG. 9.

As shown in Figures 9 and 10, the ultraviolet irradiation device according to this embodiment is configured by arranging the reflecting member 4, electrode blocks (11, 12), and light emitting tube 3 of the excimer lamp in this order relative to the main casing 2a. In this embodiment, one light emitting tube 3 of the excimer lamp is housed inside the housing 2. Note that, unlike the first embodiment, the electrode blocks (11, 12) do not have tapered surfaces (11b, 12b).

FIGS. 11 and 12 are cross-sectional views that show the arrangement of the reflective member 4 within the housing 2. FIG. 11 is a drawing when viewed in the Y direction, and FIG. 12 is a drawing when viewed in the X direction. As shown in FIG. 11, the reflective member 4 is made of a single member that has a U-shape when viewed in the Y direction. Therefore, the reflective member 4 has a reflective surface 4x that faces the center of the light-emitting tube 3 and faces each other in the X direction, and a reflective surface 4z that is located on the -Z side of the light-emitting tube 3.

As mentioned above, since the ultraviolet light L1 is generated between the electrode blocks (11, 12), it is preferable to arrange the reflecting surface 4x close to the electrode blocks (11, 12). However, taking the -X side as an example, the first end 5a of the light-emitting tube 3 is located on the -X side of the electrode block 11, and a part of the light-emitting tube 3 is arranged to protrude from the electrode block 11 to the -X side. Therefore, for example, if the reflecting surface 4x has a rectangular shape, it is difficult to bring the reflecting surface 4x close to the electrode block 11. In view of this, in this embodiment, as shown in FIG. 12, the reflecting member 4 has a cutout portion 32 that avoids interference with the light-emitting tube 3. Specifically, the reflecting surface 4x is U-shaped when viewed in the X direction, and is arranged at a position offset from the light-emitting tube 3 in the Y direction. This makes it possible to prevent interference between the light-emitting tube 3 and the reflecting surface 4x, and the reflecting surface 4x can be brought close to the electrode block 11 and arranged between the first end 5a and the electrode block 11. The same applies to the reflecting surface 4x on the +X side. In the above, the reflective surface 4x is U-shaped, but the cutout 32 may be a hole for inserting the light emitting tube 3, and the reflective surface 4x may be O-shaped.

The reflective member 4 can be formed by processing a sheet-like member made of, for example, PTFE, as described above with reference to FIG. 4. By processing the sheet-like member, it is possible to easily form a shape that matches the arrangement of the light emitting tube 3 and the electrode blocks (11, 12), as described above.

As shown in FIG. 11, the reflecting surface 4x reflects ultraviolet light L1 that has a component traveling in the X direction. This increases the amount of ultraviolet light L1 traveling toward the light extraction surface 10, improving the efficiency of extracting ultraviolet light L1 from the light extraction surface 10.

As mentioned above, the reflecting surface 4x is disposed at a position offset in the Y direction from the light emitting tube 3 when viewed in the X direction. Therefore, as shown in Figures 11 and 12, the reflecting surface 4x can reflect ultraviolet light La1 that has a component traveling in the X direction and travels at a small angle with respect to the XY plane. In this way, according to this embodiment, ultraviolet light La1 can be reflected even at a position offset in the Y direction from the light emitting tube 3 when viewed in the X direction.

The reflecting surface 4z also reflects the ultraviolet light Lb1 that is emitted from the light-emitting tube 3 and travels toward the -Z side toward the light extraction surface 10 (see FIG. 11). This allows the ultraviolet light Lb1 that travels toward the -Z side to be reflected toward the light extraction surface.

As described above, in the ultraviolet irradiation device 1 according to the second embodiment, the reflective member 4 is configured to reflect ultraviolet rays L1 having a component traveling in the X direction, as well as ultraviolet rays La1 having a small angle with respect to the Y direction, and ultraviolet rays Lb1 traveling to the -Z side. This increases the amount of ultraviolet rays traveling toward the light extraction surface 10, further improving the efficiency of extracting ultraviolet rays from the light extraction surface 10.

FIG. 13 is a perspective view showing another example of the configuration of the reflecting member 4 according to the second embodiment. As shown in FIG. 13, the reflecting member 4 may further include reflecting surfaces 4y that face each other in the Y direction.

Furthermore, FIG. 14A is a cross-sectional view showing yet another example configuration of the reflecting member 4 according to the second embodiment. As shown in FIG. 14A, the reflecting surface 4x may be inclined with respect to the XY plane on the -Z side of the reflecting surface 4x. This configuration is preferable because even if the ultraviolet light L1 is reflected by the reflecting surface 4x and travels toward the -Z side, the reflecting surface 4z reflects the ultraviolet light toward the light extraction surface.

[Modification]
Modifications of the ultraviolet irradiation device according to the present invention will now be described.

<1> In the above, the reflective surface 4x is described as being disposed between the first ends 5a and 5b of the light-emitting tube 3 in the X direction, but the reflective surface 4x may be disposed outside the light-emitting tube 3 between the first reference point P1 and the second reference point P2.

<2> Although the reflective member 4 has been described above as being formed by processing a sheet-like member, the shape of the reflective member 4 is not limited in the present invention. Fig. 14B is a perspective view of the ultraviolet irradiation device 1 showing another example of the configuration of the reflective member 4, following Fig. 2A. For example, as shown in Fig. 14B, a block material having a frame shape and a tapered surface inclined relative to the light extraction surface 10 may be placed inside the housing 2 as the reflective member 4. The tapered surface corresponds to the reflective surface (4x, 4y). The reflective member 4 can be fixed with any member such as a screw (not shown). The constituent material of the reflective member 4 is the same as that described above.

〈3〉 In the above, reference was made to ultraviolet rays with a main emission wavelength in the range of 200 nm to 240 nm, which has a low impact on humans. However, it is also conceivable that the ultraviolet irradiation device may irradiate ultraviolet rays onto a space where the presence of objects or people is not expected. In other words, there are no limitations on the wavelength of ultraviolet rays emitted by the excimer lamp.

For example, the peak wavelength of the ultraviolet light can be varied by selecting the type of luminous gas filled in the light emitting tube 3. As an example, the combination of luminous gas and peak wavelength is KrCl (222 nm), KrBr (207 nm), XeCl (308 nm), and XeBr (283 nm).

<4> In the above embodiment, the optical filter 21 can be of any configuration.

<5> The configuration of the ultraviolet irradiation device 1 described above is merely an example, and the present invention is not limited to the configurations shown in the drawings.

Reference Signs List 1, 100: ultraviolet irradiation device 2: housing 2a: main casing 2b: lid 3: light emitting tube 4: reflecting member 4x, 4y, 4z: reflecting surface 5a: first end 5b: second end 10: light extraction surface 11, 12: electrode block 11a, 12a: mounting area 11b, 12b: tapered surface 21: optical filter 30: notch 31: area 32: notch P1: first reference point P2: second reference point

Claims (11)

A housing and
a light extraction surface provided on a side surface of the housing;
an excimer lamp including a straight arc tube housed in the housing, and a first electrode and a second electrode arranged to apply a voltage to the arc tube and spaced apart from each other in a first direction parallel to a tube axis of the arc tube;
a reflecting member having a first reflecting surface facing a center portion of the arc tube and reflecting ultraviolet light having a component traveling in the first direction, and reflecting at least a portion of the ultraviolet light emitted by the excimer lamp;
an ultraviolet irradiation device, characterized in that the first reflection surface of the reflection member is disposed, with respect to the first direction, between a first reference point located near a first end of the light-emitting tube on the first electrode side and a second reference point located near a second end located opposite the first end. The ultraviolet irradiation device of claim 1, characterized in that the first reflecting surface is disposed between the first electrode and the first reference point, or between the second electrode and the second reference point. The ultraviolet irradiation device according to claim 1, characterized in that the reflecting member has a plurality of the first reflecting surfaces, and the plurality of the first reflecting surfaces face each other in the first direction. The ultraviolet irradiation device according to claim 1, characterized in that the first reflecting surface is inclined with respect to the light extraction surface, and the ultraviolet light incident on the first reflecting surface is reflected toward the light extraction surface. The ultraviolet irradiation device according to claim 1, characterized in that the reflecting member has a second reflecting surface facing the center of the light-emitting tube and reflecting ultraviolet light having a component traveling in a second direction perpendicular to the first direction on a plane parallel to the light extraction surface. The ultraviolet irradiation device according to claim 5, characterized in that the reflecting member has a plurality of the second reflecting surfaces, and the plurality of the second reflecting surfaces face each other in the second direction. The ultraviolet irradiation device according to claim 5, characterized in that the second reflecting surface is inclined with respect to the light extraction surface, and the ultraviolet light incident on the second reflecting surface is reflected toward the light extraction surface. The ultraviolet irradiation device of claim 1, characterized in that the first reflecting surface is located between the light emitting tube and the light extraction surface in a third direction perpendicular to the light extraction surface. The ultraviolet irradiation device according to claim 2, characterized in that the reflecting member includes the first reflecting surface that is positioned away from the light emitting tube in a second direction perpendicular to the first direction on a plane parallel to the light extraction surface when viewed in the first direction. The ultraviolet irradiation device of claim 1, characterized in that the reflective member is made of an insulating material. 10. The ultraviolet irradiation device according to claim 9, wherein the reflecting member is made of polytetrafluoroethylene.

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