Ultraviolet light-emitting element and ultraviolet irradiation device

Abstract

The present invention provides a safe ultraviolet light irradiation device which uses ultraviolet light that is safe to the human body, and which has a wide range of microorganism elimination and sterilization effects. Disclosed is an ultraviolet light emitting element provided with: an electrode substrate that has a pair of electrodes; at least one cylindrical or flattened cylindrical glass tube that is disposed on the electrode substrate so as to face both of the electrodes, the glass tube having both end parts sealed; a discharge gas which is sealed inside the glass tube and contains a xenon gas that generates a discharge due to a voltage applied to the electrodes; and a phosphor layer which is formed on the inner surface of the glass tube and emits light when excited by the discharge. The glass tube is formed of borosilicate glass or quartz glass. The phosphor layer is formed of a phosphoric acid-based fluorescent material, and has an emission spectrum which has a peak half-value width within the wavelength range of 50 nm or less, with the peak being at a wavelength of 230 ± 10 inm on an illuminance basis.

Description

Technical Field

[0001] The present invention relates to an ultraviolet light-emitting element and an ultraviolet irradiation device. In particular, the present invention relates to an ultraviolet light-emitting element and an ultraviolet irradiation device capable of realizing a sterilization device using ultraviolet light that is safe for the human body without using an expensive and high-performance filter for sterilization (including disinfection and sterilization) and deodorization of viruses and various bacteria.

[0002] In this specification, among ultraviolet rays (UV: Ultraviolet rays), deep ultraviolet rays (DUV: Deep Ultraviolet rays) mean radiation in the ultraviolet region with a wavelength range of 200 nm to 300 nm, and vacuum ultraviolet rays (VUV: Vacuum Ultraviolet rays) mean ultraviolet rays with a wavelength of 200 nm or less generated by rare gas discharge. Also, LAFi (Luminous Array Film) means a structure of a surface light source in which a discharge gas mixed with a phosphor, neon, and xenon is enclosed in a gas discharge tube (glass capillary), both ends of the glass tube are sealed, and a plurality of the glass capillaries are arranged side by side on an electrode substrate to emit light.

[0003] In this specification, the wavelength of ultraviolet rays has a difference of about 10 nm particularly on the short wavelength side between the case based on "photon amount (number of photons)" (herein called photon wavelength (unit: pnm)) and the case based on "illuminance" (herein called illuminance wavelength (unit: inm)). That is, the characteristics based on "photon amount (number of photons)" show characteristics shifted about 10 nm to the longer wavelength side than the characteristics based on "illuminance". The reason for this is that the illuminance (mW / cm 2) = n×h×C / wavelength. Here, n is the number of photons per unit, h is Planck's constant, and C is the speed of light. That is, there is a relationship of illuminance ∝ number of photons / wavelength. Therefore, even with the same number of photons, the illuminance is higher for shorter wavelengths, so the spectrum of the illuminance shifts towards shorter wavelengths compared to the spectrum of the number of photons. General-purpose measuring instruments with illuminance standards below 200 nm are difficult to obtain, and measurements below 200 nm are generally measured based on the photon quantity standard. As factors for the wavelength shift, the transmittance of the glass capillary and the sensitivity of the light-receiving sensor of the illuminometer may not be uniform with respect to the wavelength. Since the glass transmittance and the light-receiving sensor sensitivity may decrease as the wavelength becomes shorter, in a broadband light source, the peak wavelength of the emission spectrum shifts towards longer wavelengths.

Background Art

[0004] Conventionally, the sterilization and deodorization effects by ultraviolet rays have been well known, and various sterilization or disinfection devices by ultraviolet irradiation are known (see, for example, Patent Documents 1 to 4). Further, in Patent Document 1, it has been proposed that a wavelength of 200 to 230 nm is optimal as ultraviolet rays that are beneficial for virus inactivation and do not affect human cells. And in the device disclosed in Patent Document 1, an excimer lamp having a narrow peak wavelength at 222 nm is cited as a representative example as a light source that emits deep ultraviolet light in the above wavelength range.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, an excimer lamp that emits deep ultraviolet light with a wavelength of 222 nm uses highly toxic krypton chloride (KrCl) gas as a discharge gas. Therefore, environmental problems cannot be avoided in case of breakage. Also, at the manufacturing site of the excimer lamp, special facilities are required for gas protection. In addition, the KrCl excimer has a narrow emission wavelength range, and there is also a problem that it is difficult to efficiently sterilize all types of bacteria and viruses. That is, although a more efficient inactivating ability against bacteria and viruses can be expected in the wavelength region shorter than 222 nm, the emission wavelength of this excimer lamp is concentrated almost at 222 nm. Therefore, the excimer lamp cannot be expected to have an inactivating ability in the wavelength region shorter than 222 nm.

[0007] Furthermore, in the conventional surface-emitting ultraviolet light source device for sterilization disclosed in Patent Document 2, a light source device having a peak wavelength at around 260 nm has reached the limit of commercialization due to the restrictions of the glass material (old material) constituting the gas discharge tube and the restrictions of the phosphor material. When such a light source device is used, deep ultraviolet light with a wavelength shorter than around 240 nm generated from the light source device is absorbed by the glass material constituting the outer tube of the tube. Therefore, the development of a phosphor that generates ultraviolet light with a shorter wavelength, which can be expected to have a high sterilization effect against viruses and bacteria, and a new glass material that efficiently transmits deep ultraviolet light has been desired. Also, the new development of a technology for forming a phosphor in a glass tube for emitting deep ultraviolet light with a shorter wavelength at an appropriate emission efficiency from the new phosphor has been necessary.

[0008] Therefore, the present inventors provided a deep ultraviolet irradiation device disclosed in Patent Document 5 as a safe sterilization device that solves the above problems, has a broad sterilization and disinfection effect against many viruses and bacteria, and has little impact on the human body. This deep ultraviolet irradiation device is equipped with a broadband light source that emits ultraviolet light with a wavelength peaking around 228 nm (hereinafter, this light source is referred to as 228B).

[0009] Unlike the conventional method of emitting light with a wavelength around 222 nm, which is beneficial for bacterial inactivation, from an excimer lamp, the deep ultraviolet irradiation device of Patent Document 5 is basically based on using a gas discharge tube array type surface emitting light source device that utilizes a deep ultraviolet phosphor as a deep ultraviolet light source. The deep ultraviolet irradiation device of Patent Document 5 further utilizes a deep ultraviolet phosphor layer that is excited by the discharge of xenon (Xe, elemental symbol: Xe) gas and has a broad emission spectrum in a wavelength range of at least 210 to 250 nm with a peak around 228 nm. The deep ultraviolet irradiation device of Patent Document 5 further arranges an optical filter that reduces, that is, suppresses the transmission of, ultraviolet light in a wavelength range of 240 nm or more in the emission spectrum of the phosphor layer, facing the light emitting surface (an array surface composed of the light emitting surfaces of the arranged gas discharge tubes) as needed. This optical filter has a configuration of a dielectric multilayer film filter formed on the surface of an ultraviolet transmission substrate made of quartz, and is arranged such that the ultraviolet transmission substrate is on the side facing the light emitting surface of the surface emitting ultraviolet light source device. The ultraviolet transmission substrate functions to adjust the incident angle of the emitted light from the light emitting surface to the dielectric multilayer film filter.

[0010] As described above, in the conventional deep ultraviolet irradiation device disclosed in Patent Document 5, an optical filter is used to reduce the effective irradiance, which is an index of safety, and a safer device is provided. However, the optical filter is expensive. Furthermore, in the case of a diffusive broadband waveform such as 228B, since the optical filter has a viewing angle dependency, it is not easy to efficiently remove ultraviolet rays in the wavelength range of 240 nm or more with low safety. Therefore, it is necessary to devise the optical filter and the structure of the irradiation device, and more expensive optical filters and complex structures were required.

[0011] The present invention provides a safe ultraviolet irradiation device that has a wide range of bactericidal and sterilizing effects against many viruses and bacteria and reduces the ultraviolet rays in the wavelength range that adversely affects the human body, that is, suppresses the transmission of ultraviolet rays, without basically using an optical filter.

Means for Solving the Problems

[0012] The present invention provides an ultraviolet light emitting element including an electrode substrate having a pair of electrodes, at least one cylindrical or flat cylindrical glass tube disposed on the electrode substrate so as to face both of the electrodes and having both ends sealed, a discharge gas including xenon gas that causes discharge by a voltage applied to the electrodes and is enclosed inside the glass tube, and a phosphor layer formed on the inner surface of the glass tube and excited by the discharge to emit light. The glass tube is borosilicate glass or quartz glass, the phosphor layer is a phosphate-based fluorescent material, and shows an emission spectrum in a wavelength range having a peak wavelength of 203 ± 10 nm and a half-value width of the peak of 50 nm or less based on the illuminance standard.

[0013] The ultraviolet irradiation device according to the present invention is basically characterized by using the following new broadband light source (hereinafter referred to as the light source 203B) in order to effectively sterilize and minimize the influence on the human body. In the ultraviolet irradiation device according to the present invention, in the spectrum represented by wavelength and illuminance, the wavelength peaks at 203 ± 10 nm, preferably around 203 nm (200 nm to 208 nm). And, in the ultraviolet irradiation device according to the present invention, continuous ultraviolet rays are emitted that generate a wavelength range with a half-value width of the peak of 50 nm, preferably a wavelength range of 40 nm. Such a light source 203B is a surface-emitting light source device of a gas discharge tube array type that uses a phosphor, similar to the 228B proposed in Patent Document 5. However, compared with 228B, 203B is a light source that significantly reduces ultraviolet rays in the wavelength range of 240 nm or more that have an adverse effect on the human body. Also, the light emission from the phosphor of 203B (that is, the broadband wavelength centered around 203 nm (about 210 pnm)) is excited by vacuum ultraviolet rays emitted from Xe and emits light. This light emission is close to the broadband light centered around 180 pnm emitted from Xe through the glass tube. Therefore, in order for the light of 203B to be effectively extracted, the light of 180 pnm is incidentally extracted.

[0014] When the phosphor is irradiated with vacuum ultraviolet rays of 147 nm and / or 172 nm generated by discharge in the glass tube and caused to emit light, the ultraviolet rays inherent to the phosphor in the glass tube are defined as ultraviolet ray 1. And the ultraviolet rays extracted outside through the wall of the gas discharge tube (glass capillary) from the ultraviolet ray 1 are defined as ultraviolet ray 2. Since there is a wavelength range in which the ultraviolet ray 1 and the ultraviolet ray 2 are absorbed depending on the transmission characteristics of the glass when passing through the glass, they become ultraviolet rays with different spectral characteristics. That is, depending on the material and thickness of the glass capillary, the ultraviolet ray 2 exhibits completely different spectral characteristics from the ultraviolet ray 1, and it is a spectrum that can only be known after manufacturing the device. The ultraviolet ray 203B described later in the present invention means the ultraviolet ray 2.

[0015] As will be described in detail later, as a result of intensive research and experiments by the present inventors, it was first confirmed that 203B according to the present invention exhibits a sterilizing and disinfecting ability equal to or higher than that of conventional 228B. Furthermore, the present inventors evaluated the effective irradiance used in safety standards and found that 203B without an optical filter can ensure safety equal to or higher than that of conventional 228B in which ultraviolet rays are reduced using an optical filter, that is, the transmission of ultraviolet rays is suppressed, in the ultraviolet wavelength range of 240 nm or more. Thereby, the present inventors found that the above problems can be solved and derived the present invention.

[0016] As another aspect of the present invention, the ultraviolet irradiation device according to the present invention is basically a device that does not require an optical filter. However, when higher safety is required, it is preferable to provide an optical filter or to provide a timer to control the driving time of the surface-emitting ultraviolet light source device. As the optical filter combined in the present invention, the same one as proposed in Patent Document 5 can be used. That is, this optical filter has a configuration of a dielectric multilayer film filter formed on the surface of an ultraviolet-transmitting substrate such as quartz, and is arranged so that the ultraviolet-transmitting substrate is on the side facing the light-emitting surface of the surface-emitting ultraviolet light source device. The ultraviolet-transmitting substrate functions to adjust the incident angle of the emitted light from the light-emitting surface to the dielectric multilayer film filter.

[0017] As another aspect of the present invention, as the glass material constituting the envelope of the gas discharge tube, borosilicate glass or quartz glass having high transmittance performance in the deep ultraviolet region is used. Since borosilicate glass has the property of absorbing ultraviolet rays in the wavelength range of 175 to 200 pnm, it is possible to suppress the emission of ultraviolet rays in the vacuum ultraviolet region with a wavelength of 190 pnm or less, which generates ozone harmful to the human body. Thereby, it is possible to emit vacuum ultraviolet rays (VUV: second peak) centered around 180 pnm, which are emitted from xenon (Xe) gas enclosed as a discharge gas and taken out of the capillary glass. Also, in quartz glass, since it transmits vacuum ultraviolet rays better than borosilicate glass, it is possible to emit vacuum ultraviolet rays (VUV: second peak) centered around 173 nm. Furthermore, the present invention can utilize a surface-emitting ultraviolet light source device composed of a gas discharge tube array that can efficiently emit deep ultraviolet rays in the wavelength range of 200 nm to 250 nm, which is the deep ultraviolet included in 203B and is particularly expected to be most effective for sterilization and disinfection, from the phosphor layer.

[0018] As yet another aspect of the present invention, by using 203B as a broadband light source that emits ultraviolet rays, ultraviolet rays in the wavelength range of 240 nm or more, which have an adverse effect on the human body, are significantly reduced. Furthermore, the present invention provides an ultraviolet irradiation device that restricts the emission of ultraviolet rays on the short-wavelength side generated inside by adjusting the thickness (film thickness) of the glass tube constituting the envelope of the gas discharge tube. That is, 203B emits ultraviolet rays in the deep ultraviolet region in a wide wavelength range of 200 nm to 250 nm, which is most expected to be effective for sterilization and disinfection, but the emission of ultraviolet rays with a wavelength of 240 nm or more, which is harmful to the human body, is significantly suppressed. Furthermore, ultraviolet rays in the vacuum ultraviolet region with a wavelength of 190 nm or less, which generate ozone harmful to the human body, can be suppressed by adjusting the film thickness of the glass tube according to the glass material. For example, in the case of a glass tube using borosilicate glass, by setting the film thickness in the range of about 60 to 300 μm, it is possible to effectively suppress the emission of ultraviolet rays in the vacuum ultraviolet region with a wavelength of 200 nm or less, particularly ultraviolet rays in the vacuum ultraviolet region with a wavelength of 190 nm or less, which generate ozone harmful to the human body, from the glass tube.

[0019] As yet another aspect of the present invention, while conducting intensive research and experiments, the inventors have found that the 203B broadband light source used in the ultraviolet irradiation device according to the present invention has many advantages as described above, but also has a problem of "high temperature dependence." Therefore, the ultraviolet irradiation device according to the present invention preferably has a heat dissipation mechanism or a cooling device that suppresses or controls the temperature rise of the light source device. The heat dissipation mechanism or the cooling device may be any of those in which the structure of the substrate or the device is devised, or those in which devices or elements that actively promote cooling are provided. Specifically, for example, a slit substrate having through portions such as slits may be employed as the electrode substrate constituting the light source device. A heat sink made of ceramic, aluminum, or the like, and / or a Peltier device and a vapor chamber may be attached to the back surface of the electrode substrate. Alternatively, a cooling fan may be installed on the back surface of the light source device. The heat dissipation mechanism or the cooling device is not limited to these, but a higher effect can be obtained by using a combination of a plurality of such specific configurations. Further, when using a highly conductive heat sink made of aluminum or the like, it is necessary to attach the heat sink at a dispersed position on the back surface side of the electrode substrate and corresponding to each of the electrode pairs in order to prevent electrical short circuits.

[0020] As yet another aspect of the present invention, quartz glass or borosilicate glass is disposed at a position separated by 1 mm or more from the surface of the light source device, and air is enclosed and the periphery is sealed. When ozone (molecular formula: O3) is actively utilized, the generation of ozone is effective, but since high-concentration ozone is harmful, it is necessary to suppress the generation when it is not utilized. By adopting such a structure, ozone can be confined in the sealed space, and the diffusion of ozone to the outside can be suppressed. Incidentally, in the gap between the surface of the light source device and the quartz glass or borosilicate glass, vacuum ultraviolet rays are absorbed by oxygen to generate ozone, so ultraviolet rays with short wavelengths are cut in this gap portion. Also, as a further modification, two quartz glasses or glasses that transmit ultraviolet rays are arranged in close contact with the surface of the light source device with a gap of about 1 mm to 5 mm between them, and a panel is used in which the periphery of the light source device and the two glasses are sealed to cut off ultraviolet rays of short wavelengths.

Advantages of the Invention

[0021] According to the present invention, it is possible to realize a deep ultraviolet irradiation device having a wide range of sterilization and disinfection effects using ultraviolet rays that are highly safe for the human body without using expensive and high-performance optical filters. In addition, even when using an ultraviolet irradiation device by people who are not familiar with handling ultraviolet rays, or when using an ultraviolet irradiation device in an environment that is not designed and managed so that ultraviolet rays in a wavelength range that adversely affects the human body do not leak out, it is possible to handle a highly safe ultraviolet irradiation device. In the ultraviolet irradiation device of the present invention, the wavelength range of 200 nm to 250 nm, which is most expected to be effective for sterilization and disinfection, is widely covered, but the emission of ultraviolet rays in the deep ultraviolet region with a wavelength of 240 nm or more, which is harmful to the human body, is significantly reduced.

Brief Description of the Drawings

[0022]

Figure 1A

Figure 1B

Figure 1C

Figure 1D

Figure 1E

Figure 1F

Figure 1G

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11A

Figure 11B

Figure 12

Figure 13

Figure 14

Figure 15A

Figure 15B

Embodiments for Carrying Out the Invention

[0023] The present invention will be described in further detail with reference to the drawings. Note that the following description is illustrative in all respects and should not be construed as limiting the present invention.

[0024] [First Embodiment] [Basic Configuration and Driving Principle of Surface Emitting Ultraviolet Light Source Device] The gas discharge tube array used as the surface emitting ultraviolet light source device in the present invention is basically the same as the configuration disclosed in Patent Document 5 except for the phosphor material and glass capillary tubes used. The present invention uses a gas discharge tube array type surface emitting ultraviolet light source device characterized by not using highly toxic KrCl gas or mercury with environmental problems as a deep ultraviolet light generation source in the wavelength band (185 nm to 240 nm) beneficial for virus inactivation.

[0025] (Gas Discharge Tube) Figs. 1A to 1C are schematic views showing the configuration of a gas discharge tube array type surface emitting ultraviolet light source device in the first embodiment of the ultraviolet irradiation device according to the present invention. Fig. 1A is a cross-sectional view of a gas discharge tube serving as a deep ultraviolet light emitting element. The gas discharge tube 1 mainly includes a glass capillary tube 2 having a flat elliptical cross-section with a major axis dimension of about 2 mm and a minor axis dimension of about 1 mm and a length of 8 cm, and is provided with a deep ultraviolet phosphor layer 3 on the inner surface of the back side opposite to the ultraviolet irradiation side. Further, the gas discharge tube 1 has a configuration in which a discharge gas 4 containing a rare gas such as a mixed gas of neon (Ne, elemental symbol: Ne) and xenon (Xe) that emits vacuum ultraviolet light, or helium (He, elemental symbol: He) and xenon (Xe), or argon (Ar, elemental symbol: Ar) and xenon (Xe), or a mixed gas of krypton is enclosed inside the glass capillary tube 2 and both ends are sealed.

[0026] As the material of the glass capillary 2, inexpensive borosilicate glass or high-ultraviolet-transmittance soft glass is used when only DUV is generated. When generating VUV and DUV simultaneously, ultraviolet-transmitting borosilicate glass or quartz glass having a borosilicate composition with improved ultraviolet transmittance by adding a small amount of fluorine or the like is suitable. As such ultraviolet-transmitting borosilicate glass, for example, glass known under the trade name BU-41 of Nippon Electric Glass Co., Ltd. or SCHOTT8337B of SCHOTT can be used. Fig. 2 shows the light transmission characteristics (transmittance of the ultraviolet-transmitting glass tube) based on the photon standard of borosilicate glass. In Fig. 2, the horizontal axis represents the wavelength (pnm), and the vertical axis represents the transmittance. Since such borosilicate glass has the property of absorbing ultraviolet rays in the wavelength range of 175 to 200 pnm, the emission of ultraviolet rays in the vacuum ultraviolet region with a wavelength of 190 nm or less, which generates ozone harmful to the human body, can also be suppressed by controlling the film thickness of the glass. Lines A and B in Fig. 2 show the light transmittance of the ultraviolet-transmitting glass tubes using the trade names BU-41-2 and BU-41-3 of Nippon Electric Glass Co., Ltd. Of course, expensive quartz glass with excellent ultraviolet transmittance may be used. When manufacturing the glass capillary, the glass tube of the ultraviolet-transmitting borosilicate glass is drawn (redrawn) to a wall thickness (film thickness) of 200 μm or less, preferably about 100 μm, to reduce the wall thickness, whereby a glass capillary 2 that transmits with a transmittance of 80% or more from the vacuum ultraviolet region of about 170 nm to the deep ultraviolet region of about 280 nm can be obtained. This glass capillary 2 is made of borosilicate glass that transmits 80% or more at a wavelength of 200 pnm and 45% or less at a wavelength of 180 pnm based on the photon amount standard. However, if the wall thickness is 50 μm or less, the strength is insufficient and there is a risk of breakage, so it is not preferable.

[0027] In addition, as the deep ultraviolet phosphor layer 3 newly adopted in the present invention, for example, a phosphate-based phosphor such as scandium (element symbol: Sc) phosphate ScPO4 having a peak in the emission spectrum near a wavelength of 203 nm is used by excitation of vacuum ultraviolet rays.

[0028] As the excitation source of vacuum ultraviolet rays in the phosphor layer 3, any light source capable of emitting vacuum ultraviolet rays with an excitation wavelength of 200 nm or less may be used. For example, as such an excitation source, krypton (Kr) gas (wavelength 147 nm), xenon (Xe) gas (wavelength 173 nm), neon (Ne) (wavelength 143 nm), or a mixed gas thereof may be used.

[0029] Figure 3 is a diagram showing the emission spectra of each ultraviolet light source. The emission spectrum of the surface-emitting ultraviolet light source used in the ultraviolet irradiation device according to the present invention has a wavelength peak of 203 ± 10 nm, preferably around 203 nm (200 to 208 nm), as shown by way of example as 203B in Figure 3, due to the above-described phosphor and glass capillary. Further, in the ultraviolet irradiation device according to the present invention, ultraviolet rays are emitted that generate a wavelength range with a half-value width of the peak of 50 nm, preferably a wavelength spread of about 40 nm. According to such 203B, although there is a limit to the measurement in the low wavelength region with a peak around 203 nm, it has a continuous wide wavelength width extending approximately from 170 nm to 260 nm and emits effective vacuum ultraviolet light and deep ultraviolet light in at least the range of 180 nm to 235 nm.

[0030] Figure 3 shows the emission spectra of each light source of 228B, which has a peak wavelength near 228 nm, and a broadband light source that emits ultraviolet light with a peak wavelength near 275 nm (hereinafter referred to as this light source as 275B), in addition to 203B, which is the light source according to the present invention. In Figure 3, the wavelength is shown on the horizontal axis (unit: nm), and the illuminance of each wavelength is shown on the vertical axis as a ratio to the illuminance at the peak wavelength. Note that the basic structures of 228B and 275B are the same as that of 203B. Figure 4 is a diagram showing the action function, that is, the adverse effects (inhibition degree) on the human body caused by ultraviolet light of each wavelength (horizontal axis: unit: nm) as a coefficient. The action function shows that the coefficient value "1" is the maximum, and the lower the coefficient value, the less the adverse effect, that is, it is safer. The action function based on Figure 4 is maximum near 270 nm, that is, the coefficient value is "1", and on the long wavelength side, it is about 30% (coefficient value 0.3) near 300 nm, and on the short wavelength side, it is about 30% (coefficient value 0.3) near 240 nm. Furthermore, the action function rapidly decreases on the short wavelength side with 240 nm as the boundary.

[0031] The measurement of the emission spectrum in Figure 3 was carried out under the following conditions. The measuring instrument is Maya2000pro manufactured by Ocean Photonics. Among this spectrum, the wavelength range of 200 nm or more was measured in the illuminance mode. Since the wavelength range of 203B below 200 nm is the measurement limit in the illuminance mode of this measuring instrument, it was measured in the photon mode (see Figure 13), and it was calculated from the waveform correlation in the wavelength range of 200 nm or more between the illuminance mode and the photon mode. 203B was placed close to about 1 mm from the measurement head of the measuring instrument. The measurement head and 203B were placed in a container that can enclose nitrogen. The illuminance mode was measured in the air atmosphere, and the photon mode was measured in the nitrogen atmosphere.

[0032] Returning to FIG. 3 and comparing the spectra of the illuminance, 203B has a broad (broadband) emission spectrum with a peak in the vicinity of 203 to 204 nm. In 203B, the emission spectrum in the vicinity of 240 nm is 20% or less (about 1 / 10) of the peak, and the emission spectrum in the vicinity of 250 nm is 10% or less (about 1 / 20) of the peak. Furthermore, as the wavelength becomes longer, the emission spectrum becomes smaller. On the other hand, in 228B, the emission spectrum in the vicinity of 240 nm is about 60% of the peak, and the adverse effect (degree of inhibition) on the human body is significantly greater compared to 203B. In addition, in 275B, the illuminance of the emission spectrum is also the highest in the wavelength range near 270 nm where the action function is the highest.

[0033] Thus, the inventors of the present invention have first elucidated that 203B, which is an ultraviolet light source used in the deep ultraviolet irradiation device according to the present invention, greatly improves its safety compared to conventional ultraviolet light sources. Furthermore, when the inventors compared the sterilization performance of both the 203B according to the present invention and the conventional 228B, they first confirmed that 203B exhibits sterilization and disinfection capabilities equivalent to those of 228B.

[0034] FIG. 5 is a diagram comparing the sterilization ability of each light source as an inactivation rate to show the above-mentioned matters, and is a diagram showing the results of irradiating ultraviolet rays with three types of light sources, 203B, 228B, and 275B shown in FIG. 3, and inactivating Bacillus natto. In FIG. 5, the inactivation rate on the vertical axis indicates the value obtained by dividing the "number of remaining bacteria" after ultraviolet irradiation under each condition (the three types of light sources) by the "number of bacteria before ultraviolet irradiation". The horizontal axis of FIG. 5 indicates the irradiation dose (mJ / cm 2 )

[0035] As is clear from Fig. 5, the inactivation rate at the same irradiation dose is the lowest when irradiating 203B. It can be seen that 203B has an inactivation power equal to or greater than that of 228B and 275B. In the comparison of the three types of light sources, 203B, 228B, and 275B, the inventors of the present invention first discovered through this experiment that, in the order shown in Fig. 5, that is, 203B has an inactivation power almost equivalent to that of 228B and greater than that of 275B. In addition, in this experiment, the irradiation doses for 99.9% inactivation are approximately 8 mJ / cm 2 for 203B and 228B, and 21.5 mJ / cm 2 for 275B.

[0036] The sterilization experiment shown in Fig. 5 was conducted as follows. The bacteria used were Bacillus natto. Approximately 6 million Bacillus natto were dispersed in an aqueous solution and applied to 10 culture beds (Sanispax stamps). After that, one culture bed not irradiated with ultraviolet light was left, and the other culture beds were divided into three each and assigned to the ultraviolet light of 203B, 228B, and 275B. 203B was irradiated with three types of 4.5, 9, and 12 mJ / cm 2 , 228B was irradiated with three types of 4.3, 8.6, and 12.9 mJ / cm 2 , and 275B was irradiated with three types of 9.2, 23, and 32 mJ / cm 2 . Then, the 10 culture beds including one culture bed not irradiated with ultraviolet light were left in a thermostat at 30°C for 20 hours to culture the bacteria. After that, photos of each culture bed were taken and the number of remaining bacteria was examined. The inactivation rate of each condition was calculated by dividing the number of bacteria in each condition by the number of bacteria in the culture bed not irradiated with ultraviolet light. In addition, the sterilization effect of ultraviolet light has the same tendency for bacteria and viruses, and the effect can be represented by bacteria.

[0037] As described above, 203B, which is the light source used in the deep ultraviolet irradiation device according to the present invention, has higher safety and equal or higher inactivation power compared to 228B and 275B that have been proposed so far, and is the most efficient light source. And such a fact has been clarified for the first time by the research and experiments conducted by the inventors of the present invention. While 203B has many advantages as described above, it has been found that its illuminance varies greatly depending on the lighting time. FIG. 6 is a diagram showing the variation of illuminance with the lighting time of each ultraviolet light source, and shows the relationship between the lighting time and the illuminance for each of the light sources 203B, 228B, and 275B. In FIG. 6, the horizontal axis represents the lighting time (seconds), the left vertical axis represents the illuminance (mW / cm 2 ), and the right vertical axis represents the coefficient of variation (variation rate). In FIG. 6, the graphs represent, in order from the top, the illuminance of 228B, the variation rate of 228B, the variation rate of 275B, the variation rate of 203B, the illuminance of 275B, and the change in the illuminance of 203B. As is clear from the graph, compared to 228B and 275B, 203B rapidly decreases in illuminance in a short time, and its variation rate is also large.

[0038] The measurements of the measured values shown in FIG. 6 were performed as follows. Each of 203B, 228B, and 275B was driven using a self-made inverter with a light source having an irradiation surface with a size of 8 cm x 6 cm. A voltage of 12V was applied to the inverter, and the current was 1.4A. The illuminance was measured non-contact from a distance of 5 mm from the light source surface using a handy type simple illuminance meter. Since this handy type simple measuring instrument cannot capture the full wavelength of each light source, although it is a relative value, there is no problem in measuring the relative value of the illuminance variation with the lighting time.

[0039] FIG. 7 is a diagram showing the time variation of illuminance and temperature with the lighting time. In FIG. 7, the horizontal axis represents the lighting time (seconds), and the left vertical axis represents the illuminance (mW / cm 2) On the right vertical axis, temperature (°C) is indicated. The graphs, from top to bottom, represent the changes in the temperature of 203B, the illuminance of 228B, the temperature of 228B, and the illuminance of 203B. All the graphs show the case where the light source devices of 203B and 228B are cooled by blowing air on them. As is clear from FIG. 7, for both 203B and 228B, the temperature rises and the illuminance decreases as the lighting time of the ultraviolet light source elapses. Thus, it can be seen that the decrease in illuminance depends on the temperature rise accompanying the passage of the lighting time, and that the fluctuations in temperature rise and illuminance decrease with the passage of the lighting time are larger for 203B than for 228B. Also, as shown in FIG. 7, when cooled by blowing air, the temperature rise is less and the decrease in illuminance is also less compared to the case of FIG. 6 without cooling.

[0040] The measurements of the measured values shown in FIG. 7 were performed as follows. For 203B and 228B, a light source with an irradiation surface of 8 cm x 6 cm was used in the same manner as in FIG. 6. The temperature and illuminance were measured at the same time. The measurement of the illuminance has already been described above, but the temperature was measured non - contact using an infrared thermometer and measured for a predetermined irradiation time.

[0041] FIG. 8 is a diagram showing the change in illuminance with respect to the change in temperature in the 203B light source. In FIG. 8, the horizontal axis indicates temperature (°C), and the left vertical axis indicates illuminance (mW / cm 2)On the right vertical axis, the ratio of illuminance to room temperature is shown. In the graph of Fig. 8, graphs D and C use a 203B light source with an 8x6 cm irradiation surface using a slit substrate. Fig. 8 shows the case where two 203B light sources are each placed on the machine and driven to measure the temperature and illuminance while allowing the temperature to rise without cooling (graph D), and the case where the light sources are floated 1.5 cm from the machine to facilitate cooling by wind (about 4 m / s) and measure the temperature and illuminance (graph C). Since graph D is not cooled, the temperature rises to 62 degrees, while graph C with a fan only rises to 42 degrees. Also, in both cases, as the temperature rises, the illuminance decreases. Graphs A and B are the relationships between the temperature and illuminance of graphs D and C respectively, normalized by the illuminance at 25 °C. From the fact that graphs A and B draw almost the same curve up to 42 degrees with respect to the temperature rise, it can be seen that the illuminance is a function of temperature. From this curve, it can be seen that by suppressing the temperature rise within 10 degrees, the illuminance can be suppressed with a 10% variation.

[0042] Therefore, as is clear from Fig. 8, in the 203B light source according to the present invention, suppressing the temperature rise is essential for stable operation. Therefore, it is necessary to cool the 203B light source by adopting a slit substrate, air cooling by a fan, adopting a heat sink, water cooling, attaching a Peltier element, etc. to suppress the temperature rise. For example, a heat dissipation mechanism such as a heat sink or a cooling device such as a Peltier element or a vapor chamber may be attached to the back surface of the 203B light source, either alone or in combination, for heat dissipation or cooling. By suppressing the temperature rise to about 35 degrees or less in this way, the variation in illuminance can be suppressed within 90% of the initial value, and the stabilization of the irradiation amount can be achieved. This will be described in detail later with reference to Figs. 15A, 15B, etc.

[0043] 〔Surface-emitting ultraviolet light source device〕 Now, let's continue the explanation by referring back to FIGS. 1A to 1C. As shown in FIGS. 1A and 1B, a plurality of gas discharge tubes 1 as ultraviolet light emitting elements are arranged in parallel on an electrode substrate 11 having an electrode pair 12 (a pair of electrodes 12X and 12Y), thereby forming a surface emitting ultraviolet light source device 10 of a gas discharge array type. The electrode substrate 11 has, for example, a polyimide-based insulating substrate 13 as a base body, supports the arrangement of the gas discharge tubes 1 with an adhesive layer 14 on its upper surface, and has the electrode pair 12 on the opposing lower surface. The electrode pair 12 is further covered with an electrode coating layer (insulating layer) 15. The electrode substrate 11 includes the electrode pair 12, the insulating substrate 13, the adhesive layer 14, and the electrode coating layer 15.

[0044] In order to enhance the heat dissipation effect or cooling effect of the surface emitting ultraviolet light source device 10, a heat dissipation mechanism or a cooling device 16 is selectively provided as needed on the lower surface side of the electrode pair 12 constituting the surface emitting ultraviolet light source device 10 (the back side of the electrode coating layer (insulating layer) 15 in the electrode substrate 11). As the heat dissipation mechanism 16, for example, a heat sink 17 as shown in FIGS. 1D and 1E is used. It is preferable to use a heat sink 17 made of ceramic or aluminum, but it is not limited thereto. When using a metal heat sink 17 such as aluminum, in order to prevent electrical short circuits, it is necessary to divide it into a plurality of parts (at least two parts as shown in FIG. 1E) and attach them so as to correspond to the exposed back surface of the electrode coating layer 15 (see FIG. 1A) and each of the electrodes 12X and 12Y (see FIG. 1B).

[0045] Furthermore, in order to further enhance the heat dissipation effect or cooling effect of the surface-emitting ultraviolet light source device 10, as the cooling device 16, for example, a Peltier device 18 as shown in FIG. 1F may be selectively used as needed. In this case, the Peltier device 18 is provided such that the heat absorption plate 182 side is in contact with the back surface of the electrode coating layer 15 constituting the electrode substrate 11. In the Peltier device 18, a metal electrode connected to the power supply line 185, an N-type semiconductor 183, and a P-type semiconductor 184 are alternately connected between the heat dissipation plate 181 and the heat absorption plate 182 arranged vertically. Then, when a current flows from the power supply line 185, the heat absorbed by the heat absorption plate 182 moves to the heat dissipation plate 181 and is released from the heat dissipation plate 181 due to the Peltier effect. Thereby, the heat generated in the surface-emitting ultraviolet light source device 10 is effectively released into the atmosphere through the heat absorption plate 182 and the heat dissipation plate 181. The cooling device 16 is not limited to the Peltier device, and for example, a vapor chamber may be used instead of the Peltier device. Further, as shown in FIG. 1G, if a heat sink 17 is attached to the heat dissipation plate 181 side of the Peltier device 18 and the two are combined and used as a composite body, the heat on the heat dissipation plate 181 side of the Peltier device 18 can be efficiently removed, and the function of the Peltier device 18 can be maximally exerted. Therefore, the heat dissipation effect or cooling effect of the surface-emitting ultraviolet light source device 10 can be further enhanced. Incidentally, instead of the heat sink 17, a vapor chamber may be attached to the heat dissipation plate 181 side of the Peltier device 18 and used as a means for effectively removing the heat on the heat dissipation plate 181 side of the Peltier device 18. Hereinafter, when the heat sink 17 and / or the Peltier device 18 are used, the surface-emitting ultraviolet light source device 10 including the heat sink 17 and / or the Peltier device 18 is referred to.

[0046] The gas discharge array type surface-emitting ultraviolet light source device 10 shown in Fig. 1B has a structure in which an electrode pair 12 is formed on the lower surface of an insulating substrate 13, and an array of gas discharge tubes 1 is supported by an adhesive layer 14 that also serves as an insulating layer on the upper surface of the insulating substrate 13. The electrode pair 12 is disposed at the bottom rear of each gas discharge tube 1 and consists of an electrode 12X and an electrode 12Y in a pattern that spreads on both sides with a common electrode slit (electrode gap G) in between.

[0047] If the insulating substrate 13 serving as the base of the electrode substrate 11 is made of an insulating film of a polyimide-based resin and the gas discharge tubes 1 are arranged with gaps between them, a flexible surface-emitting ultraviolet light source device 10 that can be curved in the tube array direction as a whole can be configured. Also, if a ventilation slit is formed in the electrode substrate 11 so that the bottom surface of each gas discharge tube 1 is partially exposed to the outside, it is convenient for heat dissipation and / or cooling to suppress or control the temperature rise of each gas discharge tube 1.

[0048] When providing a ventilation slit in the electrode substrate 11 facing the gas discharge tube 1 so that the bottom surface of each gas discharge tube 1 is partially exposed to the outside, a V-shaped or substantially U-shaped groove slit (non-penetrating type) or a slit (vent hole) penetrating the electrode substrate 11 is provided in a direction orthogonal to the arrangement direction of the discharge tubes 1. By providing the ventilation slit in a direction orthogonal to the arrangement direction of the tubes, the heat generated from each gas discharge tube 1 can be released to the outside almost evenly, and air can be blown to each gas discharge tube 1 almost evenly. For this reason, the heat dissipation and / or cooling effect of the surface-emitting ultraviolet light source device 10 can be enhanced, and the temperature rise can be efficiently suppressed or controlled. As a result, the decrease in illuminance of the surface-emitting ultraviolet light source device 10 can be suppressed, and the stabilization of the irradiation amount can be realized. In addition, when providing a heat dissipation mechanism or a cooling device 16 in the configuration of forming the electrode pair 12 on the lower surface of the insulating substrate 13 shown in FIGS. 1A and 1B, it may be arranged on the lower surface side of the insulating substrate 13, that is, on the lowermost surface side of the electrode substrate 11. In any case, the present invention is not limited to this configuration. In addition, hereinafter, when using a heat dissipation mechanism or a cooling device 16 (heat sink 17 and / or Peltier element 18, etc.), the electrode substrate 11 or the surface-emitting ultraviolet light source device 10 including the heat dissipation mechanism or the cooling device 16 (heat sink 17 and / or Peltier element 18, etc.) is referred to.

[0049] 〔Driving Principle〕 FIG. 1C is a schematic diagram for explaining the driving principle of the surface-emitting ultraviolet light source device 10. For the electrodes 12X and 12Y constituting the electrode pair 12, the inverter circuit 19 applies an alternating driving voltage with a peak-to-peak voltage (P-P voltage) of 1000 to 2000 V and a frequency of 30 to 40 kHz. In the rising process of the alternating driving voltage applied by the inverter circuit 19, initial discharge occurs in the discharge gap in the gas discharge tube 1 corresponding to the electrode gap G between the electrodes 12X and 12Y. Subsequently, as the alternating driving wave voltage rises, the discharge expands in the longitudinal direction of the gas discharge tube 1.

[0050] By applying the alternating drive voltage, such discharges occur alternately and repeatedly in the region within the gas discharge tube 1 corresponding to the electrodes 12X and 12Y while alternating the polarity of the accumulated charges. When the gas enclosed in the gas discharge tube 1 is a mixed gas of neon (Ne) and xenon (Xe), a discharge accompanied by the emission of vacuum ultraviolet rays (VUV) of 143 pnm and 172 pnm occurs at a lower discharge voltage compared to other gases. Due to the excitation of this VUV, ultraviolet rays are emitted from the phosphor layer 3, and ultraviolet rays with a central wavelength of 203 nm are emitted after passing through the glass tube. This driving principle and the specific driving circuit are described in detail in the aforementioned Patent Document 2.

[0051] [Second Embodiment] Hereinafter, a second embodiment of the present invention will be described in detail with reference to the drawings. As described above, the ultraviolet irradiation device according to the present invention basically does not require an optical filter. However, in order to further enhance safety, an optical filter may be provided, and further, a timer may be provided to control the driving time of the surface-emitting ultraviolet light source device.

[0052] FIG. 9 is a cross-sectional configuration diagram showing a second embodiment of the ultraviolet irradiation device. More specifically, FIG. 9 shows the cross-sectional configuration of the ultraviolet irradiation device when the optical filter 20 is combined with the surface-emitting ultraviolet light source device 10 according to the present invention having the structure shown as the first embodiment in FIGS. 1A to 1G and the emission spectrum shown as 203B in FIG. 3.

[0053] The optical filter 20 to be combined here can be the same as that proposed in Patent Document 5, but it is desirable to have filter characteristics that transmit shorter wavelengths. That is, the optical filter 20 has a dielectric multilayer film filter 22 with a thickness of about 1 to 2 μm, including an ultraviolet-transmitting substrate, preferably a synthetic quartz substrate 21 with a thickness of about 1 mm, and an oxide film (for example, an oxide film such as hafnium oxide (molecular formula: HfO2) / silicon dioxide (SiO2)) formed thereon. This optical filter 20 mainly transmits deep ultraviolet light of 190 to 230 nm and shields ultraviolet light of 240 nm or more, which is highly likely to have an adverse effect on human tissues, that is, it has the characteristic of effectively blocking the transmission of ultraviolet light.

[0054] By the way, the deep ultraviolet light from the surface-emitting ultraviolet light source device 10 (sometimes referred to as the gas discharge tube array 10) used as the light source in the present invention has a wide emission angle. On the other hand, the dielectric multilayer film filter 22 combined with the surface-emitting ultraviolet light source device 10 has an incident angle dependence. Therefore, in a configuration where the emitted light from the surface-emitting ultraviolet light source device 10 is directly incident on the dielectric multilayer film filter 22, the light in the peripheral part of the ultraviolet light emitted at a wide angle cannot pass through the optical filter 20 sufficiently. This point is explained in Patent Document 5.

[0055] When the optical filter 20 is combined with the surface-emitting ultraviolet light source device 10, in order to maximize its effect, it can be done as follows. That is, also in the present invention, the quartz substrate 21 is located on the incident surface side of the optical filter 20 so that the deep ultraviolet radiation light from the surface-emitting ultraviolet light source device 10 passes through the dielectric multilayer film filter 22 as efficiently as possible, and the two are combined and arranged. In such an arrangement configuration, the quartz substrate 21 functions as an optical element that converts the incident angle light of the light in the part with a large emission angle among the deep ultraviolet light emitted at a wide angle from each gas discharge tube 1 into the optical filter 20 at a position in front of the dielectric multilayer film filter 22.

[0056] In FIG. 9, the state of refraction of the emitted light from the emission surface of the gas discharge tube 1 to the dielectric multilayer filter 22 is indicated by the arrow line 23. The emitted light from the emission surface of the gas discharge tube 1 constituting the surface-emitting ultraviolet light source device 10 is incident on the dielectric multilayer filter 22 with the emission angle corrected in the direction in which the incident angle is narrowed due to the difference between the refractive index of the space between the quartz substrate 21 (air n≈1) and the refractive index of the quartz substrate 21 (n = 1.5). As a result, it is possible to suppress the attenuation of the emission intensity of deep ultraviolet light centered on 203 nm that is emitted through the optical filter 20.

[0057] In addition, in order to reduce the incidence loss of the deep ultraviolet emitted light 23 radiated at a wide angle from the surface-emitting ultraviolet light source device 10 to the dielectric multilayer filter 22, stripes or lattice pattern ribs that function as a diffraction grating may be further provided on the incident surface side of the quartz substrate 21 constituting the optical filter 20. The incident angle of the deep ultraviolet rays radiated at a wide angle from each gas discharge tube 1 of the surface-emitting ultraviolet light source device 10 to the dielectric multilayer filter 22 can be narrowed by the stripe ribs corresponding to the arrangement pitch of the gas discharge tubes 1.

[0058] Furthermore, each of the glass tubes of the plurality of gas discharge tubes 1 may further have a reflective layer formed on the outer surface of the back side facing the electrode substrate 11 or the side surface facing the adjacent glass tube to reflect ultraviolet rays from the inside of each glass tube. Also, by providing a metal film such as aluminum on the adhesive layer 14 located between the gas discharge tubes 1, 1 in the surface-emitting ultraviolet light source device 10, the light radiated at a wide angle is reflected forward to reduce the incident angle to the filter, and the light can be effectively radiated to the front surface. Also, even when no filter is used, ultraviolet rays can be effectively radiated to the front surface by this method.

[0059] FIG. 10 is a table comparing the effective irradiation illuminance in each method. The table in FIG. 10 shows various light sources and the effective irradiation illuminance (an index of the degree of inhibition: unit: mJ / cm 2) is a relative comparison. As various light sources, four types are included: 228B, the combination of 228B and an optical filter, 203B, and the combination of 203B and an optical filter. In FIG. 10, the effective irradiation illuminance of ultraviolet rays (vacuum ultraviolet region) with wavelengths of 180 to 240 nm of the above four types of various light sources, the effective irradiation illuminance of ultraviolet rays (the region where there are few obstacles in the UVC region) with wavelengths of 200 to 240 nm, the effective irradiation illuminance of ultraviolet rays with wavelengths of 240 to 300 nm, and the effective irradiation illuminance of ultraviolet rays with wavelengths of 180 to 300 nm are shown. The optical filter used is the above-mentioned optical filter 20 that effectively shields ultraviolet rays with wavelengths of 240 nm or more (that is, substantially prevents the transmission of ultraviolet rays). The lower the numerical value of the effective radiant illuminance, the higher the safety. The numerical values of the effective irradiation illuminance in FIG. 10 are integrated values obtained by performing a sum-of-products calculation of the emission spectrum in FIG. 3 and the action function in FIG. 4 for each wavelength. The action function in FIG. 4 is a relative value without a unit. The spectrum in FIG. 3 is described as a relative value without a unit for each waveform comparison, but the unit is mW / cm 2 or μW / cm 2 and becomes the irradiation power per unit area. In FIG. 10, the calculated values with the unit of μW / cm 2 are described.

[0060] As is clear from FIG. 10, the ultraviolet irradiation device using the above-mentioned 203B light source according to the present invention has a lower effective irradiation illuminance in the wavelength range of 180 to 300 nm and higher safety than the ultraviolet irradiation device using the conventional 228B light source alone and the ultraviolet irradiation device combining the 228B light source and an optical filter, even without using an optical filter. That is, the total effective irradiation illuminance in the wavelength range of 180 to 300 nm is 50.3 μW / cm 2 when the 203B light source is used alone, and 257.9 μW / cm 2Therefore, it can be seen that using only the 203B light source is safer. Also, as shown in the comparison table of FIG. 10, if this 203B light source is used in combination with the optical filter 20 shown in FIG. 9, further improvement in safety can be achieved. Thus, the 203B light source according to the present invention can provide an ultraviolet irradiation device with high safety even without using an optical filter in combination. Also, in cases where higher safety is required, such as in special cases or when used by people with little knowledge or experience in handling ultraviolet rays, an extremely safe ultraviolet irradiation device can be provided by using it in combination with the optical filter 20 shown in FIG. 9. As shown in FIG. 10, in the combination of the 203B light source and the optical filter, the illuminance of ultraviolet rays with a wavelength of 240 nm or more is 0, so it is the safest among the compared light sources.

[0061] Effective irradiance E in FIG. 10 eff is an index regarding safety shown in the guidelines published by the GLA (Global Lighting Association). The smaller E eff is, the higher the safety is considered. The emission spectrum φ(λ) is obtained based on the illuminance standard, and the effective irradiance E eff is obtained by multiplying the emission spectrum φ(λ) and the action function S(λ) shown in FIG. 4. That is, the effective irradiance E(λ) at wavelength λ = emission spectrum φ(λ) × action function S(λ). Therefore, the effective irradiance of the target spectrum is obtained by integrating the product of all spectral wavelengths at each wavelength. That is, the total effective irradiance E eff is obtained by ∫ emission spectrum φ(λ) × action function S(λ) dλ. Here, λ is the wavelength (measured based on the illuminance standard and the unit is nm)

[0062] [Third Embodiment] FIG. 11A is a view showing an ultraviolet irradiation device according to a third embodiment of the present invention, and is a schematic perspective view showing an assembled configuration of the ultraviolet irradiation device. The ultraviolet irradiation device shown in FIG. 11A includes a base substrate 30 having an air introduction hole (not shown), a drive circuit board 40 provided on the base substrate 30, and a blower fan 50 provided above the drive circuit board 40. This ultraviolet irradiation device further includes a surface-emitting ultraviolet light source device 60 provided above the blower fan 50, and an optical filter 20 provided above the surface-emitting ultraviolet light source device 60 as needed. And those (the surface-emitting ultraviolet light source device 60 and the optical filter 20) are assembled and supported by four columns 31 in order from the bottom. The surface-emitting ultraviolet light source device 60 is the same as the surface-emitting ultraviolet light source device 10 in FIGS. 1A to 1G or FIG. 9, and the optical filter 20 may be selectively provided according to the environment in which the ultraviolet irradiation device is used, the user, etc. The entire structure of the ultraviolet irradiation device is housed in a housing 70 illustrated by a dotted line having an ultraviolet irradiation window (opening) upward. In FIG. 11A, for convenience, the light emitting surface of the surface-emitting ultraviolet light source device 60 is substantially horizontal, and the ultraviolet irradiation device is illustrated such that the irradiation direction of ultraviolet rays is upward, but the irradiation direction can be arbitrarily determined.

[0063] Here, as the surface-emitting ultraviolet light source device 60, an electrode substrate 61 with slits as shown in FIG. 11B is used. That is, similar to the electrode substrate 11 described above with reference to FIG. 1B, the electrode substrate 61 shown in FIG. 11B has a plurality of through slits 64 penetrating the electrode substrate 61 including electrodes 12X and 12Y substantially parallel to the gap G for the discharge gap. In such an electrode substrate 61 with slits, the bottom surface (rear surface) of the arranged gas discharge tubes 1 is partially exposed outward downward, and ventilation holes are formed at the intersection of the gaps between adjacent gas discharge tubes and the through slits 64. stateThus, the surface-emitting ultraviolet light source device 60 can be effectively cooled by the flow of the cooling air passing through the ventilation holes from the blower fan 50. Note that the ventilation holes provided in the electrode substrate 61 are not limited to the slit shape as described above, and may be in a form in which a large number of small holes are dispersedly arranged so that the back surface of the discharge tube is partially exposed to the outside.

[0064] [Fourth Embodiment] FIG. 12 is a schematic diagram showing the configuration of an ultraviolet irradiation device that generates ozone. The ultraviolet irradiation device shown in FIG. 12 includes a base substrate 30 having ventilation holes (not shown), a surface-emitting ultraviolet light source device 10 of a gas discharge tube array type provided above the base substrate 30, an optical filter 20 provided on the front side (light-emitting surface side) of the surface-emitting ultraviolet light source device 10, a drive circuit board 40 provided on the back side of the surface-emitting ultraviolet light source device 10, and a housing 70 indicated by a dotted line that houses these (the base substrate 30, the surface-emitting ultraviolet light source device 10, the optical filter 20, and the drive circuit board 40). The housing 70 has a window portion that emits ultraviolet light on a wall portion facing the optical filter 20. The arrangement of the optical filter 20 is arbitrary and may be omitted. A space that acts as an ozone generation space 51 is formed on the front side of the surface-emitting ultraviolet light source device 10, which is the ultraviolet irradiation side (when the optical filter 20 is arranged, between the light source device 10 and the optical filter 20). Also, a space that functions as a heat dissipation path 52 is formed between the surface-emitting ultraviolet light source device 10 and the drive circuit board 40. Inside the housing 70, a blower fan 50 is provided facing one end surfaces of the ozone generation space 51 and the heat dissipation path 52. The housing 70 has an exhaust port on a wall portion facing the other end surfaces of the ozone generation space 51 and the heat dissipation path 52. By the blowing from the blower fan 50 during driving, the ozone in the ozone generation space 51 is discharged to the outside through the exhaust port, and the heat generated by the gas discharge tube array 10 and the drive circuit board 40 is released to the outside through the heat dissipation path 52 and the exhaust port. In FIG. 12, the case where the blower fan 50 is arranged on the lateral side (one end side) of the surface-emitting ultraviolet light source device 10 is illustrated, but it may be arranged on the back side of the light source device 10, and is not limited to the case illustrated here. Also in Embodiment 4, the surface-emitting ultraviolet light source device 10 is the same as the surface-emitting ultraviolet light source device 10 described in FIGS. 1A to 1G or FIG. 9, and the optical filter 20 may be selectively provided according to the environment in which the ultraviolet irradiation device is used, the user, etc.

[0065] In the fourth embodiment, regarding each gas discharge tube 1 constituting the surface-emitting ultraviolet light source device 10, as mainly described with reference to FIG. 1A, the glass capillary 2 is made of quartz glass or thin borosilicate glass with high ultraviolet transmittance. The short wavelength side of the vacuum ultraviolet light with a peak wavelength of 172 nm generated from the discharge of xenon (Xe) gas in the tube 1 is absorbed by the glass of the glass capillary 2. Then, vacuum ultraviolet light with a peak around 180 nm is radiated into the space inside the tube 1. Therefore, in the space inside the tube 1, there are simultaneously radiated a deep ultraviolet emission spectrum (DUV) having a wavelength width of at least 180 to 230 nm with a peak wavelength (first peak) of around 210 nm (203 nm) (210 ± 10 nm) of the phosphor layer 3 and vacuum ultraviolet light (VUV) having a peak wavelength (second peak) around 180 nm (180 ± 10 nm). FIG. 13 is a diagram showing the emission spectrum characteristics of the 203B light source according to the present invention. In FIG. 13, the horizontal axis represents the wavelength (nm), and the vertical axis represents the number of photons. Also, in FIG. 13, the emission spectra of VUV (light A) and DUV (light B) from the gas discharge tube array type surface-emitting ultraviolet light source device of the 203B light source shown in FIG. 12 are shown. In the present embodiment, the phosphor layer 3 has a first peak wavelength at which the illuminance with respect to the wavelength is maximum in the range of 203 ± 10 nm (preferably 200 to 208 nm) based on the illuminance standard, and the full width at half maximum of the first peak is in the wavelength range of 50 nm (see FIG. 3). There is also a second peak with an illuminance lower than that of the first peak, and the wavelength of the second peak is in the range of 180 ± 10 nm based on the photon amount standard, and the spectrum width of the value 70% of the peak value of the second peak is in the wavelength range of 20 nm (see FIG. 13). Alternatively, in the present embodiment, the phosphor layer 3 has a first peak wavelength at which the illuminance with respect to the wavelength is maximum in the range of 203 ± 10 nm (preferably 200 to 208 nm) based on the illuminance standard, and the full width at half maximum of the first peak is in the wavelength range of 50 nm (see FIG. 3). There is also a second peak with an illuminance lower than that of the first peak, and the wavelength of the second peak is in the range of 173 ± 5 nm based on the photon amount standard, and the full width at half maximum of the second peak is in the wavelength range of 20 nm (see FIG. 13).Although not clearly shown in Fig. 13, the short-wavelength side of the emission is absorbed due to the wavelength transmission characteristics of glass and air. Based on the idea that as the wavelength transmission characteristics approach a more uniform state (where the transmittance does not decrease even on the short-wavelength side), the peak at 180 pnm shifts to 173 pnm. For example, when the transmittance of the glass significantly decreases at wavelengths of 200 nm or less on the short-wavelength side, or when there is light absorption on the short-wavelength side due to oxygen in the air, the second peak at 180 pnm, like light B in Fig. 13, does not appear. However, as the decrease in transmittance on the short-wavelength side is gradually alleviated, the second peak at 180 pnm, like light A, begins to appear. Further increasing the transmittance on the short-wavelength side causes the second peak at 180 pnm to shift towards 173 pnm. In the case where there is no influence from glass transmittance or light absorption by oxygen, it theoretically coincides with the molecular beam emission peak of Xe gas.

[0066] Fig. 13 shows that vacuum ultraviolet rays are absorbed by the air layer. That is, in Fig. 13, light A and light B respectively show the spectra when the light-emitting element of 203B is measured in a nitrogen atmosphere and an air atmosphere. Since there is no absorption of vacuum ultraviolet rays in the nitrogen atmosphere, the light reaches a photodetector about 5 mm away up to a wavelength range of 170 nm and is detected (light A). On the other hand, in the air atmosphere, light in the wavelength range of 190 nm or less is absorbed by oxygen between the light and the photodetector to generate ozone and thus is not detected. That is, light in the wavelength range of 190 nm or less is cut off (light B). The distance between the surface of 203B shown in Fig. 12 and the measurement head of the photodetector (not shown) was set to 5 mm. In 203B, the overvoltage applied to the inverter was 12 V and the current was 1.4 A. Since there is no absorption of vacuum ultraviolet rays in the nitrogen atmosphere, light up to a wavelength range of 170 nm reaches a photodetector about 5 mm away, so the spectrum of light A is obtained. On the other hand, in the air, light in the range of 190 nm or less is absorbed by oxygen to generate ozone before reaching the photodetector, that is, since light in the range of 190 nm or less is cut off and not detected, the spectrum of light B is detected. Incidentally, each bump-shaped peak at 190 nm or less occurs because ozone reacts with light and the light is absorbed. The difference between light A and light B contributes to the generation of ozone.

[0067] The drive circuit board 40 is equipped with a drive circuit including an inverter circuit 19 (see FIG. 1C) that supplies an alternating drive voltage to the surface-emitting ultraviolet light source device 10, a timer that controls the irradiation time, a control circuit that controls the entire ultraviolet irradiation device, and the like. When the surface-emitting ultraviolet light source device 10 is driven by the drive circuit, deep ultraviolet light with a peak wavelength in the vicinity of 203 nm and a wavelength of 240 nm or less passes through the optical filter 20 and is irradiated, and the air in the irradiation space and the object are sterilized and disinfected.

[0068] On the other hand, among the vacuum ultraviolet light generated in the gas discharge tube 1, the phosphor layer 3 having an ultraviolet reflection function reflects it, and vacuum ultraviolet light with a wavelength in the vicinity of 180 nm is radiated from the light emitting surface. Among the vacuum ultraviolet light, light with a wavelength of 190 nm or less decomposes the air existing in the ozone generation space 51 between the light emitting surface of each gas discharge tube 1 constituting the surface-emitting ultraviolet light source device 10 and the optical filter 20 to generate ozone. The principle of ozone generation by ultraviolet light is known, but briefly explained, the vacuum ultraviolet light (VUV: light A) generated in the gas discharge tube 1 is radiated into the air in the ozone generation space 51 outside the tube 1, and the vacuum ultraviolet light (VUV: light A) chemically reacts with oxygen in the air to generate ozone. More specifically, when an oxygen molecule absorbs a photon, which is a particle of ultraviolet light, it dissociates into oxygen atoms, and the oxygen atoms combine with oxygen molecules to generate ozone.

[0069] The ozone generated inside the housing 70 is exhausted to the outside through the exhaust port together with the air from the blower fan 50, thereby exerting a sterilizing effect on the ambient air. Of course, since ozone itself has a strong oxidizing effect and toxicity, it is extremely effective for sterilization, disinfection, and deodorization in an unmanned enclosed space regardless of the concentration. However, on the other hand, excessive release into a manned environmental space must be restricted. However, low-concentration ozone is harmless to the human body and extremely beneficial for space sterilization. Therefore, it is necessary to control the ozone released into a manned space so that the ozone concentration does not exceed the specified reference value of 0.1 ppm. Incidentally, in the surface-emitting ultraviolet light source device 10 with a light-emitting area of 8×3 cm in which 12 gas discharge tubes with a length of 8 cm are arranged, 20 mg of ozone can be generated per hour. The amount of ozone generated using such a surface-emitting ultraviolet light source device can be appropriately controlled by intermittently applying a driving alternating voltage and changing its duty ratio, and it is also possible to feedback the monitored value of the ozone concentration in the environmental space and control the driving to be on / off.

[0070] [Fifth Embodiment] FIG. 14 is a schematic configuration diagram showing an ultraviolet irradiation device according to the fifth embodiment of the present invention. When ozone is actively utilized, the generation of ozone as in the fourth embodiment is effective. However, since ozone is harmful, it is necessary to suppress its generation when it is not utilized. In FIG. 14, the light source 10 is the same as the surface-emitting ultraviolet light source device 10 (see FIGS. 1B and 9) used in the above-described embodiments. As shown in FIG. 14, in this ultraviolet irradiation device, an optical filter 20 or a quartz plate 73 is arranged with a gap of about 5 mm on the front side of the light source 11, that is, on the ultraviolet radiation side. At the same time, a sealing member 72 is arranged or coated around the periphery between the light source 10 and the quartz plate 73, thereby forming a sealed space 71 between the light source 10 and the quartz plate 73. Note that the quartz plate 73 may or may not have a filter function.

[0071] The effects of the fifth embodiment will be described with reference to FIG. 13. As shown in FIG. 13, light A is an emission spectrum measured with an ultraviolet light source placed in a nitrogen (N2) atmosphere. The emission spectrum of light A has two peak wavelengths at around 180 pnm and around 210 pnm, which are vacuum ultraviolet. On the other hand, light B is an emission spectrum measured with the same light source placed in the atmosphere. The emission spectrum of light B rapidly attenuates at wavelengths shorter than around 190 pnm. This is because photons are absorbed by oxygen molecules to generate ozone. That is, according to the ultraviolet irradiation device according to the fifth embodiment shown in FIG. 14, the atmosphere is enclosed in the sealed space 71, and by sealing the periphery between the light source 10 and the optical filter 20 (see FIG. 9) or the quartz plate 73, the ozone generated in the sealed space 71 can also be contained. At the same time, the ozone layer in the sealed space 71 absorbs light (vacuum ultraviolet light) of 190 pnm or less. Therefore, the generated ozone does not leak out of the sealed space 71, and since light of 190 pnm or less does not exit the quartz plate 73, ozone is not generated outside the quartz plate 73. Therefore, according to the fifth embodiment, when ozone is not actively utilized, the release of harmful ozone to the outside can be suppressed or prevented. In the case of this embodiment shown in FIG. 14, since it is necessary to create the sealed space 71, a heat dissipation slit (through hole) cannot be provided in the substrate of the light source 10, but if the following is done, a slit can be provided in the substrate of the light source 10. In this case, two substrates that transmit ultraviolet light are prepared, and while enclosing air in the space between the two substrates, the periphery is sealed to form a panel, and by arranging this panel on the front side (light emitting surface side) of the light source 10, the same effect (ozone external release suppression effect) can be obtained.

[0072] [Summary of measures for temperature rise of 203B light source] Figure 15A is a table showing the increase in the surface temperature of 203B under various conditions. In the table of Figure 15A, the irradiation time (seconds) is shown on the left end, and the temperature (°C) changes under the conditions (1) to (7) are represented over time. In Figure 15A, (1) is the condition of a substrate with a slit, placed on a table, without a fan. (2) is the condition of floating the substrate with a slit by 1.5 cm and blowing air from the side. (3) is the condition of blowing air from the back of the substrate with a slit by a fan. (4) is the condition of providing a ceramic heat sink on the back of the substrate with a slit. (5) is the condition of providing an aluminum heat sink on the back of the substrate with a slit. (6) is the condition of providing an aluminum heat sink on the back of the substrate without a slit. (7) is the condition of blowing air from the back of the substrate without a slit by a fan. Also, Figure 15B is a graph of the numerical values in Figure 15A, with the irradiation time (seconds) on the horizontal axis and the temperature (°C) on the vertical axis. The data in Figure 15A and Figure 15B were obtained by using the surface-emitting ultraviolet light source device 10 in Figure 1B, adopting various heat dissipation methods or cooling methods, and examining the heat dissipation method or cooling method and the temperature rise suppression effect. As shown in (1) to (7) of Figure 15A, as heat dissipation methods or cooling methods, methods such as providing a slit on the electrode substrate, blowing air using a fan, and providing a ceramic or aluminum heat sink are used alone or in combination. Note that in each of the methods (1) to (7), the Peltier elements shown in Figures 1F and 1G are not used.

[0073] As is clear from the results shown in Figure 15A and Figure 15B, it was found that by each of the methods (2) to (6), even when continuously operating the 203B light source driven by LAFi shown in Figure 1B for about 4 minutes, the temperature rise can be suppressed to about 10 to about 15 °C. By adopting each of these methods (2) to (6), according to the temperature and illuminance characteristics in Figure 8, the decrease in illuminance due to a 10 °C temperature rise can be suppressed to about 10%, and it was found that it does not substantially pose a problem in practical use. According to such a combination of heat dissipation and cooling, the irradiation amount required as the ultraviolet irradiation amount of the surface-emitting ultraviolet light source device 10 (illuminance (mW / cm 2In order to obtain (the product of the illuminance and the irradiation time (seconds)), it becomes possible to secure the irradiation time even if the illuminance is somewhat suppressed, and for example, there is no need to control the irradiation time while managing the temperature.

[0074] [Summary] According to the present invention, it is possible to obtain a safe ultraviolet irradiation device having a wide range of sterilization and disinfection effects using ultraviolet rays that are safe for the human body without using an expensive and high-performance optical filter. Further, according to the present invention, it is possible to obtain an ultraviolet sterilization device equipped with an ultraviolet irradiation device, and it is also possible to obtain an ultraviolet sterilization lighting device equipped with an ultraviolet irradiation device and a lighting device. Aspects of this invention include combinations of any of the above-described multiple aspects. In addition to the above-described embodiments, there can be various modifications of this invention. Those modifications should not be construed as not belonging to the scope of this invention. This invention should include the meaning equivalent to the claims and all modifications within the above scope.

Explanation of Reference Numerals

[0075] 1: Gas discharge tube, 2: Glass capillary tube, 3: Phosphor layer, 4: Discharge gas, 10, 60: Surface-emitting ultraviolet light source device, light source device, gas discharge tube array, light source, 11, 61: Electrode substrate, 12: Electrode pair, 12X, 12Y: Electrodes, 13: Insulating substrate, 14: Adhesive layer, 15: Electrode coating layer (insulating layer), 16: Heat dissipation mechanism, cooling device, 17: Heat sink, 18: Peltier element 19: Inverter circuit, 20: Optical filter, 21: Quartz substrate, synthetic quartz substrate, 22: Dielectric multilayer film filter, 23: Radiation light, arrow line, 30: Base substrate, 31: Support column, 40: Drive circuit board, 50: Blower fan, 51: Ozone generation space, 52: Heat dissipation path, 64: Through slit, 70: Housing, 71: Sealed space, 72: Sealing member, 73: Quartz plate, 181: Heat dissipation plate, 182: Heat absorption plate, 183: N-type semiconductor, 184: P-type semiconductor, 185: Power supply line, G: Electrode gap

Claims

1. An ultraviolet light-emitting element comprising: an electrode substrate having a pair of electrodes; at least one cylindrical or flat cylindrical glass tube disposed on the electrode substrate so as to face any of the electrodes and having both ends sealed; a discharge gas enclosed in the glass tube and containing xenon gas that causes discharge by a voltage applied to the electrodes; and a phosphor layer formed on the inner surface of the glass tube and excited by the discharge to emit light, wherein the phosphor layer exhibits an emission spectrum having a peak wavelength in the range of 200 to 208 nm based on illuminance and a half-value width of the peak in a wavelength range of 50 nm or less.

2. An ultraviolet light-emitting element comprising: an electrode substrate having a pair of electrodes; at least one cylindrical or flat cylindrical glass tube disposed on the electrode substrate so as to face any of the electrodes and having both ends sealed; a discharge gas enclosed in the glass tube and containing xenon gas that causes discharge by a voltage applied to the electrodes; and a phosphor layer formed on the inner surface of the glass tube and excited by the discharge to emit light, wherein the glass tube transmits light emitted inside the glass tube, the phosphor layer emits light from the phosphor layer, and the light transmitted through the glass tube and taken out to the outside exhibits an emission spectrum having a peak wavelength in the range of 203 ± 10 nm based on illuminance and a half-value width of the peak in a wavelength range of 50 nm or less.

3. An ultraviolet light-emitting element comprising: an electrode substrate having a pair of electrodes; at least one cylindrical or flat cylindrical glass tube disposed on the electrode substrate so as to face any of the electrodes and having both ends sealed; a discharge gas enclosed in the glass tube and containing xenon gas that causes discharge by a voltage applied to the electrodes; and a phosphor layer formed on the inner surface of the glass tube and excited by the discharge to emit light, wherein the glass tube transmits 80% or more of the light emitted inside the glass tube at a wavelength of 200 nm based on photon standards, and the phosphor layer exhibits an emission spectrum in which the wavelength of a first peak at which the illuminance with respect to the wavelength is maximum is in the range of 203 ± 10 nm based on illuminance, the half-value width of the first peak is in a wavelength range of 50 nm, and there is a second peak having a lower illuminance than the first peak, the wavelength of the second peak is in the range of 180 ± 10 nm based on photon amount standards, and the spectral width of a value 70% of the peak value of the second peak is in a wavelength range of 20 nm.

4. The ultraviolet light-emitting element according to claim 2, wherein the peak wavelength is in the range of 200 to 208 in m based on the illuminance standard.

5. The ultraviolet light-emitting element according to claim 3, wherein the wavelength of the first peak is in the range of 200 to 208 in m based on the illuminance standard.

6. The ultraviolet light-emitting element according to claim 1 or 2, wherein the emission intensity of light having a wavelength of 250 in m based on the illuminance standard, which is emitted from the phosphor layer, is 10% or less of the emission intensity of the peak wavelength.

7. The ultraviolet light-emitting element according to claim 3, wherein the emission intensity of light having a wavelength of 250 in m based on the illuminance standard, which is emitted from the phosphor layer, is 10% or less of the emission intensity of the wavelength of the first peak.

8. The ultraviolet light-emitting element according to claim 1 or 2, wherein the emission intensity of light in a wavelength region of 240 in m or more based on the illuminance standard, which is emitted from the phosphor layer, is 20% or less of the emission intensity of the peak wavelength.

9. The ultraviolet light-emitting element according to claim 3, wherein the emission intensity of light in a wavelength region of 240 in m or more based on the illuminance standard, which is emitted from the phosphor layer, is 20% or less of the emission intensity of the first peak.

10. An electrode substrate having a pair of electrodes; At least one glass tube having a cylindrical or flat cylindrical shape disposed on the electrode substrate so as to face any of the electrodes and having both ends sealed; A discharge gas containing xenon gas that causes discharge by a voltage applied to the electrodes and is enclosed inside the glass tube; A phosphor layer formed on the inner surface of the glass tube and excited by the discharge to emit light, and comprising: The glass tube transmits 80% or more of the light emitted inside the glass tube at a wavelength of 200 pn m based on the photon amount standard and 45% or less at a wavelength of 180 pn m; The phosphor layer emits light from the phosphor layer, and the light taken out of the glass tube exhibits an emission spectrum in which the peak wavelength at which the illuminance is maximum is in the range of 203 ± 10 in m based on the illuminance standard and the half-value width of the peak is in a wavelength range of 50 n m.

11. An electrode substrate having a pair of electrodes; At least one glass tube having a cylindrical or flat cylindrical shape disposed on the electrode substrate so as to face any of the electrodes and having both ends sealed; A discharge gas containing xenon gas that causes discharge by a voltage applied to the electrodes and is enclosed inside the glass tube; A phosphor layer formed on the inner surface of the glass tube and excited by the discharge to emit light, and comprising: The phosphor layer has a first peak wavelength at which the illuminance with respect to the wavelength is maximum within a range of 203 ± 10 nm based on the illuminance standard, and a half-value width of the first peak within a wavelength range of 50 nm. There is also a second peak with an illuminance lower than that of the first peak, where the wavelength of the second peak is within a range of 173 ± 5 nm based on the photon amount standard, and the half-value width of the second peak is within a wavelength range of 20 nm. The ultraviolet light emitting device exhibits an emission spectrum with such characteristics.

12. The phosphor layer has a first peak wavelength at which the illuminance with respect to the wavelength is maximum within a range of 203 ± 10 nm based on the illuminance standard, and a half-value width of the first peak within a wavelength range of 50 nm. There is also a second peak with an illuminance lower than that of the first peak, where the wavelength of the second peak is within a range of 180 ± 10 nm based on the photon amount standard, and the spectral width at a value of 70% of the peak value of the second peak is within a wavelength range of 20 nm. The ultraviolet light emitting device according to claim 10 exhibits an emission spectrum with such characteristics.

13. The ultraviolet light emitting device according to any one of claims 1 to 3, 10, and 11, wherein the phosphor layer contains ScPO4 as a fluorescent material.

14. The ultraviolet light emitting device according to any one of claims 1 to 3, 10, and 11, wherein the glass tube is borosilicate glass, high ultraviolet transmittance soft glass, or quartz glass.

15. An ultraviolet irradiation device comprising the ultraviolet light emitting device according to any one of claims 1 to 3, 10, and 11 having a plurality of the glass tubes, and a heat dissipation mechanism or a cooling device disposed on the back side of the ultraviolet light emitting device to suppress the temperature rise of each glass tube during light emission.

Images