WO2023112940A1 - Optical filter and sterilization device - Google Patents

Optical filter and sterilization device Download PDF

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Publication number
WO2023112940A1
WO2023112940A1 PCT/JP2022/045959 JP2022045959W WO2023112940A1 WO 2023112940 A1 WO2023112940 A1 WO 2023112940A1 JP 2022045959 W JP2022045959 W JP 2022045959W WO 2023112940 A1 WO2023112940 A1 WO 2023112940A1
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diffraction
film
optical filter
wavelength
refractive index
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PCT/JP2022/045959
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French (fr)
Japanese (ja)
Inventor
裕助 姫井
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日本電気硝子株式会社
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Priority to JP2023567801A priority Critical patent/JPWO2023112940A1/ja
Publication of WO2023112940A1 publication Critical patent/WO2023112940A1/en

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L2/00—Methods or apparatus for disinfecting or sterilising materials or objects other than foodstuffs or contact lenses; Accessories therefor
    • A61L2/02—Methods or apparatus for disinfecting or sterilising materials or objects other than foodstuffs or contact lenses; Accessories therefor using physical phenomena
    • A61L2/08—Radiation
    • A61L2/10—Ultraviolet radiation
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/20—Filters
    • G02B5/28—Interference filters

Definitions

  • the present invention relates to an optical filter capable of selectively transmitting light in a specific wavelength range and a sterilization device using the optical filter.
  • Patent Document 1 discloses a band-pass filter formed so as to maximize the transmittance of specific ultraviolet light with a wavelength of 250 nm or less.
  • the top and bottom of the cavity layer made of the dielectric film are covered with metal thin films.
  • Patent Literature 1 describes that the metal thin film has a film thickness such that the transmittance of light in the visible region in a band-pass filter is 10% or less.
  • the cavity layer is a layer made of a dielectric film, and that silicon dioxide, lanthanum fluoride, magnesium fluoride, aluminum oxide, hafnium oxide, etc. are used as the dielectric.
  • An optical filter according to Aspect 3 is Aspect 1 or 2, wherein the dielectric multilayer film includes a high refractive index film having a relatively high refractive index and a low refractive index film having a relatively low refractive index.
  • the high refractive index film is preferably a film containing the hafnium oxide.
  • the optical filter according to Aspect 5 has a minimum spectral transmittance of 50% or more at a wavelength of 220 nm to 225 nm at an incident angle of 0°.
  • the maximum spectral transmittance at a wavelength of 240 nm to 320 nm is preferably 5% or less.
  • the transparent substrate 2 has a rectangular plate shape.
  • the transparent base material 2 may have, for example, a disk-like shape, and the shape is not particularly limited.
  • the transparent substrate 2 has a first major surface 2a and a second major surface 2b facing each other.
  • a dielectric multilayer film 3 is provided as a filter section on the first main surface 2a of the transparent base material 2 .
  • the dielectric multilayer film 3 is a multilayer film having a high refractive index film 4 with a relatively high refractive index and a low refractive index film 5 with a relatively low refractive index.
  • a multilayer film is configured by alternately laminating the high refractive index film 4 and the low refractive index film 5 on the first main surface 2a of the transparent substrate 2 in this order.
  • the crystallization parameter P in the following formula (1) may be 0.7 or more, where Ia is the diffraction intensity of the amorphous diffraction peak.
  • a pseudo-Voigt function is used as the fitting function. Further, by the nonlinear least squares method, the diffraction angle (2 ⁇ ) and the full width at half maximum of each fitting peak are determined so that the residual sum of squares between the measured X-ray diffraction profile and the combined profile of each fitting peak is minimized. (FWHM), the integrated intensity (I), and the mixture ratio of the Lorentzian and Gaussian functions are optimized.
  • excimer lamps and the like had the problem of emitting a small amount of ultraviolet light with a wavelength of 240 nm to 320 nm, which is harmful to the human body.
  • ultraviolet rays when trying to suppress the transmission of ultraviolet rays with a wavelength of 240 nm to 320 nm, it is difficult to sufficiently transmit ultraviolet rays with a wavelength of 220 nm to 225 nm.
  • ultraviolet rays There is a problem that it is difficult to achieve a high level of both high-efficiency transmission of ultraviolet rays.
  • the crystallization parameter P in the above formula (1) obtained by the above X-ray diffraction measurement is preferably 0.8 or more, more preferably 0.9 or more, still more preferably 1.0 or more, It is preferably 2.0 or less, more preferably 1.8 or less, still more preferably 1.5 or less.
  • the crystallization parameter P is within the above range, the transmission of ultraviolet rays with a wavelength of 240 nm to 320 nm can be more reliably suppressed, and the ultraviolet rays with a wavelength of 220 nm to 225 nm can be more effectively transmitted.
  • the optical filter 1 has a minimum spectral transmittance of preferably 50% or more, more preferably 60% or more, and even more preferably 70% or more at a wavelength of 220 nm to 225 nm.
  • ultraviolet rays useful for sterilizing the skin can be transmitted more effectively.
  • the upper limit of the minimum value of the spectral transmittance at wavelengths of 220 nm to 225 nm is not particularly limited, it can be set to 95%, for example.
  • the optical filter 1 preferably has a maximum spectral transmittance of 5% or less, more preferably 3% or less, still more preferably 2.5% or less, and particularly preferably 1% or less at a wavelength of 240 nm to 320 nm. .
  • a maximum spectral transmittance of 5% or less, more preferably 3% or less, still more preferably 2.5% or less, and particularly preferably 1% or less at a wavelength of 240 nm to 320 nm.
  • the lower limit of the maximum spectral transmittance at wavelengths of 240 nm to 320 nm is not particularly limited, it can be set to 0.2%, for example.
  • the spectral transmittance can be obtained, for example, by measuring the spectral transmittance of the entire optical filter 1 using a spectrophotometer (manufactured by Hitachi High-Tech Science, product number "UH4150").
  • measurement can be performed from the main surface 1a side of the optical filter 1, with an incident angle of 0° and a measurement wavelength of 190 nm to 400 nm.
  • the incident angle is defined as an angle inclined with respect to the normal direction of the stacking direction (thickness direction) of the dielectric multilayer film 3 perpendicular to the direction along the main surface 1a of the optical filter 1. (eg, ⁇ in FIG. 1). Therefore, the direction along the normal direction has an incident angle of 0°.
  • the optical filter 1 has excellent transmittance of ultraviolet rays having a wavelength of 220 nm to 225 nm, so that ultraviolet rays useful for sterilizing the skin can be effectively transmitted.
  • the optical filter 1 can suppress the transmission of ultraviolet rays having a wavelength of 240 nm to 320 nm, it is possible to suppress the transmission of ultraviolet rays that are harmful to the human body.
  • the optical filter 1 of the present embodiment for example, when used in an ultraviolet irradiation device such as an excimer lamp, it is possible to effectively emit ultraviolet rays useful for sterilization while suppressing transmission of ultraviolet rays harmful to the human body. can be permeated.
  • the thickness of one layer of the high refractive index film 4 is not particularly limited, but is preferably 5 nm or more, more preferably 10 nm or more, preferably 60 nm or less, and more preferably 50 nm or less.
  • the total thickness tH of the high refractive index film 4 is preferably 250 nm or more, more preferably 300 nm or more, still more preferably 400 nm or more, particularly preferably 500 nm or more, preferably 1000 nm or less, more preferably 800 nm or less, and even more preferably. is 700 nm or less, particularly preferably 600 nm or less.
  • the total thickness tH of the high refractive index film 4 is equal to or greater than the above lower limit, it is possible to more effectively transmit ultraviolet rays having a wavelength of 220 nm to 225 nm. In addition, transmission of ultraviolet rays having a wavelength of 240 nm to 320 nm can be further suppressed.
  • the total thickness tH of the high refractive index film 4 is equal to or less than the above upper limit, it is possible to more effectively transmit ultraviolet rays with a wavelength of 220 nm to 225 nm.
  • the thickness per layer of the low refractive index film 5 is not particularly limited, but is preferably 5 nm or more, more preferably 10 nm or more, preferably 80 nm or less, and more preferably 60 nm or less.
  • the total thickness t L of the low refractive index film 5 is preferably 500 nm or more, more preferably 600 nm or more, still more preferably 700 nm or more, particularly preferably 800 nm or more, preferably 2000 nm or less, more preferably 1700 nm or less, and even more preferably. is 1500 nm or less, particularly preferably 1400 nm or less.
  • the total thickness t L of the low refractive index film 5 is equal to or greater than the above lower limit, transmission of ultraviolet rays having a wavelength of 240 nm to 320 nm can be further suppressed.
  • the total thickness t L of the low refractive index film 5 is equal to or less than the above upper limit, it is possible to more effectively transmit ultraviolet rays with a wavelength of 220 nm to 225 nm.
  • the ratio ( tH / tL ) between the total thickness tH of the high refractive index film 4 and the total thickness tL of the low refractive index film 5 is preferably 0.2 or more, more preferably 0.3 or more, and further Preferably 0.4 or more, particularly preferably 0.5 or more, most preferably 0.6 or more, preferably 1 or less, more preferably 0.9 or less, still more preferably 0.8 or less, particularly preferably 0 0.75 or less.
  • the ratio (t H /t L ) is equal to or higher than the above lower limit, ultraviolet rays with a wavelength of 220 nm to 225 nm can be transmitted more effectively. Further, when the ratio (t H /t L ) is equal to or less than the above upper limit, transmission of ultraviolet rays with a wavelength of 240 nm to 320 nm can be further suppressed.
  • the total thickness of the dielectric multilayer film 3 is not particularly limited, but is preferably 800 nm or more, more preferably 1000 nm or more, still more preferably 1100 nm or more, particularly preferably 1200 nm or more, most preferably 1500 nm or more, and preferably 3000 nm or less. It is more preferably 2500 nm or less, still more preferably 2200 nm or less, particularly preferably 2000 nm or less, and most preferably 1900 nm or less.
  • the total thickness of the dielectric multilayer film 3 is equal to or greater than the above lower limit, it is possible to more effectively transmit ultraviolet rays having a wavelength of 220 nm to 225 nm.
  • the number of layers of the films constituting the dielectric multilayer film 3 is preferably 20 layers or more, more preferably 25 layers or more, still more preferably 30 layers or more, particularly preferably 35 layers or more, and preferably 100 layers or less. , more preferably 80 layers or less, still more preferably 60 layers or less, and particularly preferably 45 layers or less.
  • the number of layers of the films constituting the dielectric multilayer film 3 is equal to or greater than the above lower limit value, it is possible to more effectively transmit ultraviolet rays having a wavelength of 220 nm to 225 nm. In addition, transmission of ultraviolet rays having a wavelength of 240 nm to 320 nm can be further suppressed. Further, when the number of layers of the films constituting the dielectric multilayer film 3 is equal to or less than the above upper limit value, it is possible to more effectively transmit ultraviolet rays having a wavelength of 220 nm to 225 nm.
  • the dielectric multilayer film 3 is provided on the first main surface 2a of the transparent substrate 2. As shown in FIG. however, in the present invention, the dielectric multilayer film 3 may also be provided on the second main surface 2b of the transparent substrate 2. FIG. That is, the dielectric multilayer film 3 may be provided on both main surfaces of the transparent substrate 2, or may be provided only on one main surface of the transparent substrate 2. good.
  • the high refractive index film 4 and the low refractive index film 5 are laminated in order from the high refractive index film 4 on the first main surface 2 a of the transparent substrate 2 .
  • the low refractive index film 5 and the high refractive index film 4 may be laminated in order from the low refractive index film 5 on the first main surface 2a of the transparent substrate 2 .
  • an antireflection film may be provided on the second main surface 2b of the transparent substrate 2.
  • ultraviolet rays with a wavelength of 220 nm to 225 nm can be transmitted more effectively.
  • the antireflection film is not particularly limited, and for example, a multilayer film having a high refractive index film with a relatively high refractive index and a low refractive index film with a relatively low refractive index can be used.
  • the multilayer film may be configured by alternately providing a high refractive index film and a low refractive index film in this order.
  • the high refractive index film for example, a film containing hafnium oxide as a main component can be used.
  • the low refractive index film include films containing silicon oxide, aluminum oxide, zirconium oxide, tin oxide, silicon nitride, or the like as a main component.
  • the number of layers of films constituting the multilayer film can be, for example, 4 or more and 100 or less.
  • a film other than an antireflection film may be laminated on the second main surface 2b of the transparent substrate 2 as long as the effects of the present invention are not impaired. Further, a film other than the dielectric multilayer film 3 may be provided on the first main surface 2a of the transparent substrate 2 as long as the effects of the present invention are not impaired. In this case, a film may be provided between the transparent substrate 2 and the dielectric multilayer film 3 , or a film may be provided on the dielectric multilayer film 3 .
  • a transparent substrate 2 is prepared.
  • a dielectric multilayer film 3 is formed on the first main surface 2a of the transparent substrate 2.
  • the dielectric multilayer film 3 can be formed by alternately laminating the high refractive index film 4 and the low refractive index film 5 on the first main surface 2a of the transparent substrate 2 in this order.
  • the high refractive index film 4 and the low refractive index film 5 can each be formed by a sputtering method.
  • the temperature of the substrate when forming the high refractive index film 4 is preferably 300° C. or less, more preferably 270° C. or less.
  • the obtained optical filter 1 can more effectively transmit ultraviolet rays with a wavelength of 220 nm to 225 nm while further suppressing transmission of ultraviolet rays with a wavelength of 240 nm to 320 nm.
  • the lower limit of the temperature of the substrate when forming the high refractive index film 4 can be set to 20° C., for example.
  • the high refractive index film 4 is formed by, for example, using a target of the material constituting the high refractive index film 4, setting the flow rate of an inert gas such as argon gas as a carrier gas to 50 sccm to 500 sccm, and applying an electric power of 0.5 sccm. It can be performed as 5 kW to 40 kW.
  • the low refractive index film 5 is formed by, for example, using a target of the material constituting the low refractive index film 5, setting the flow rate of an inert gas such as argon gas as a carrier gas to 50 sccm to 500 sccm, and applying an electric power of 0.5 sccm. It can be performed as 5 kW to 40 kW.
  • the obtained film-coated transparent substrate is heat-treated at a temperature of 450° C. or higher, for example.
  • the optical filter 1 can be obtained.
  • the film-coated transparent substrate is heated at a temperature of 450° C. or higher, the content of cubic hafnium oxide crystals can be relatively increased, and the above formula (1 ) can be made much larger. Therefore, in the obtained optical filter 1, it is possible to more effectively transmit ultraviolet rays with a wavelength of 220 nm to 225 nm while further suppressing transmission of ultraviolet rays with a wavelength of 240 nm to 320 nm.
  • the temperature of the heat treatment for the film-coated transparent substrate is preferably 500°C or higher, more preferably 550°C or higher, preferably 800°C or lower, and more preferably 750°C or lower.
  • the temperature of the heat treatment is within the above range, it is possible to further suppress the transmission of ultraviolet rays having a wavelength of 240 nm to 320 nm and further increase the transmittance of ultraviolet rays having a wavelength of 220 nm to 225 nm.
  • the heat treatment time for the film-coated transparent substrate is not particularly limited, but can be, for example, 10 minutes or more and 120 minutes or less.
  • the diffraction intensity of the diffraction peak due to the ( ⁇ 1 1 1) crystal plane derived from the monoclinic hafnium oxide crystal is small. is preferred.
  • the intensity of the diffraction peak due to the (-1 1 1) crystal plane derived from the monoclinic hafnium oxide crystal is preferably at the microcrystal level, and the height of the peak intensity is the height of the peak intensity of the amorphous halo. It is more preferable to be within 3 times.
  • the crystallization parameter P in the above formula (1) obtained by the above X-ray diffraction measurement can be adjusted to the above preferred range.
  • the transmittance of ultraviolet rays with a wavelength of 240 nm to 320 nm can be further suppressed, and the transmittance of ultraviolet rays with a wavelength of 220 nm to 225 nm can be further enhanced.
  • the crystallization parameter P in the above formula (1) obtained by the above-described X-ray diffraction measurement is, for example, the total number, film thickness, and material of the films constituting the dielectric multilayer film 3, It can be adjusted to a suitable range depending on the heat treatment temperature of the material.
  • the crystallization parameter P in the above formula (1) obtained by the above X-ray diffraction measurement can be adjusted to a more suitable range by the heat treatment temperature of the film-coated transparent substrate.
  • the obtained optical filter 1 it is possible to more effectively increase the transmittance of ultraviolet rays with a wavelength of 220 nm to 225 nm while further suppressing the transmission of ultraviolet rays with a wavelength of 240 nm to 320 nm.
  • FIG. 2 is a schematic cross-sectional view showing an optical filter according to a second embodiment of the invention.
  • the outermost layer 26 of the dielectric multilayer film 23 is the high refractive index film 4 made of hafnium oxide.
  • Other points are the same as in the first embodiment.
  • the crystallization parameter P in the formula (1) obtained by the above X-ray diffraction measurement is 0.7 or more. Therefore, the optical filter 21 can also effectively transmit ultraviolet rays with a wavelength of 220 nm to 225 nm while suppressing transmission of ultraviolet rays with a wavelength of 240 nm to 320 nm.
  • the irradiated light may deteriorate the device members and generate acidic gas.
  • the gas corrodes the film of the optical filter, which changes the optical characteristics and may not satisfy the required characteristics.
  • the outermost layer 26 is made of hafnium oxide, it is possible to further suppress the erosion due to the acidic gas, thereby further suppressing the change in the optical characteristics. can.
  • the thickness of the outermost layer 26 is preferably 1 nm or more, more preferably 2 nm or more, preferably 10 nm or less, more preferably 7 nm or less.
  • the thickness of the outermost layer 26 is equal to or greater than the above lower limit, erosion due to acidic gases can be further suppressed, and changes in optical properties can be further suppressed.
  • the thickness of the outermost layer 26 is equal to or less than the above upper limit, it is possible to further suppress the transmission of ultraviolet rays with a wavelength of 240 nm to 320 nm, and to transmit the ultraviolet rays with a wavelength of 220 nm to 225 nm more effectively.
  • FIG. 3 is a schematic diagram showing a sterilization device according to one embodiment of the present invention.
  • the sterilization device 31 includes a housing 32 , a light source 33 and an optical filter 1 .
  • a light source 33 is arranged which emits light in a wavelength range of 190 nm to 230 nm.
  • the light source 33 and the optical filter 1 are provided so as to face each other.
  • the dielectric multilayer film 3 is preferably provided on the light source 33 side.
  • an object 34 to be sterilized is irradiated with emitted light emitted from the light source 33 through the optical filter 1 .
  • an excimer lamp can be used as the light source 33 .
  • the excimer lamp it is preferable to use an excimer lamp that emits ultraviolet light having a wavelength of 220 nm to 225 nm.
  • an excimer lamp for example, a KrCl excimer lamp can be used.
  • the excimer lamp may be a KrBr excimer lamp.
  • the sterilization device 31 of this embodiment uses the optical filter 1 described above, it is possible to efficiently transmit ultraviolet rays useful for sterilization. Therefore, the object 34 to be sterilized can be efficiently sterilized with ultraviolet light.
  • the DNA in the cells of organisms to be sterilized such as bacteria can be selectively inactivated by the action of ultraviolet light.
  • viruses can be selectively inactivated by the action of ultraviolet rays.
  • the sterilizer 31 is more preferably used for inactivating microorganisms to be treated.
  • a synthetic quartz glass substrate manufactured by USTRON
  • a dielectric multilayer film was formed by sputtering on one main surface of the prepared transparent substrate.
  • a hafnium target was sputtered to form a hafnium oxide film (HfO 2 film) on one main surface of the transparent substrate.
  • the flow rates of argon gas and oxygen gas were each set to 100 sccm, and the power applied to the target (film formation power) was set to 4 kW.
  • a silicon target was sputtered to form a silicon oxide film (SiO 2 film) on the HfO 2 film.
  • the flow rates of argon gas and oxygen gas were set to 100 sccm, and the power applied to the target (film formation power) was set to 4 kW.
  • a dielectric multilayer film having a total of 38 layers, in which HfO 2 films and SiO 2 films are alternately laminated one by one, is formed on one main surface of the transparent substrate. to obtain a film-coated transparent substrate.
  • the substrate temperature was set at room temperature (20° C.) during film formation.
  • the thickness of each layer in the film-coated transparent substrates produced in Production Examples 1 to 4 is as shown in Table 1 below.
  • Example 1 an optical filter was obtained by heat-treating the film-coated transparent substrate obtained in Production Example 1 at a temperature of 500° C. for 60 minutes in an air atmosphere.
  • Examples 2 to 16 optical filters were obtained by heat-treating the film-coated transparent substrates obtained in each production example in an air atmosphere at the temperatures and times shown in Table 2 below.
  • the film-coated transparent substrates obtained in each production example were used as they were as optical filters without being subjected to heat treatment.
  • FIG. 4 is a diagram showing the X-ray diffraction spectra of the optical filters obtained in Example 2 and Comparative Example 1.
  • the optical filters of Examples 1, 3 to 16 and Comparative Examples 2 to 4 were also subjected to X-ray diffraction measurement.
  • the diffraction intensity Ia of was obtained.
  • a pseudo-Voigt function was used as the fitting function.
  • the diffraction angle (2 ⁇ ) and the full width at half maximum (FWHM), integrated intensity (I), and the mixture ratio of Lorentzian and Gaussian functions were optimized.
  • the integrated intensity of the diffraction peak due to the ( ⁇ 1 1 1) crystal plane derived from the monoclinic hafnium oxide crystal (monoclinic HfO 2 ) when the optimum fitting result is obtained is defined as the diffraction intensity Im .
  • the integrated intensity of the diffraction peak due to the (1 1 1) crystal plane derived from the cubic hafnium oxide crystal (cubic HfO 2 ) is defined as the diffraction intensity Ic
  • the amorphous hafnium oxide (amorphous HfO 2 ) The integrated intensity of the derived diffraction peak was defined as the diffraction intensity Ia .
  • the peak fitting was performed using Rigaku's product number "PDXL".
  • Table 2 shows the results of cubic HfO 2 , monoclinic HfO 2 , and amorphous HfO 2 .
  • spectral transmittance The spectral transmittance of the optical filters of Examples 1 to 16 and Comparative Examples 1 to 4 was measured using a spectrophotometer (manufactured by Hitachi High-Tech Science, product number "UH4150"). Specifically, the incident angle (incidence angle) was set to 0°, and the measurement wavelength was set to 190 nm to 400 nm. An example of the transmission spectrum of the obtained optical filter is shown in FIG.
  • Example 5 is a diagram showing transmission spectra of the optical filters obtained in Example 2 and Comparative Example 1.
  • FIG. 5 As shown in FIG. 5, in Example 2, it can be confirmed that the minimum value of the spectral transmittance at wavelengths of 220 nm to 225 nm is increased.
  • Comparative Example 1 the minimum spectral transmittance at wavelengths of 220 nm to 225 nm could not be sufficiently increased.
  • the maximum value of the spectral transmittance at wavelengths of 240 nm to 320 nm is lowered.
  • the optical filters of Examples 1 to 16 in which the crystallization parameter P is 0.7 or more can effectively transmit ultraviolet rays having a wavelength of 220 nm to 225 nm. (minimum value of spectral transmittance at wavelength 220 nm to 225 nm is 50% or more). Moreover, as is clear from Table 2, the optical filters of Examples 1 to 16 can suppress the transmission of ultraviolet rays having a wavelength of 240 nm to 320 nm.
  • the optical filters of Comparative Examples 1 to 4 in which the crystallization parameter P is less than 0.7, cannot sufficiently transmit ultraviolet rays with wavelengths of 220 nm to 225 nm (spectral transmission at wavelengths of 220 nm to 225 nm). % minimum less than 50%).
  • Reference Signs List 1 21 Optical filter 1a Main surface 2 Transparent substrate 2a First main surface 2b Second main surface 3, 23 Dielectric multilayer film 4 High refractive index film 5 Low refractive index film 26 ... outermost layer 31 ... sterilization device 32 ... housing 33 ... light source 34 ... object to be sterilized

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Abstract

The present invention provides an optical filter which is capable of effectively transmitting ultraviolet light that has a wavelength of 220 nm to 225 nm, while suppressing transmission of ultraviolet light that has a wavelength of 240 nm to 320 nm.　An optical filter 1 according to the present invention is provided with a transparent base material 2 and a multilayer dielectric film 3 that contains hafnium oxide and is arranged on the transparent base material 2; and if Ic is the diffraction intensity of a diffraction peak of the (1 1 1) crystal plane associated with a cubic hafnium oxide crystal, Im is the diffraction intensity of a diffraction peak of the (-1 1 1) crystal plane associated with a monoclinic hafnium oxide crystal, and Ia is the diffraction intensity of a diffraction peak associated with an amorphous hafnium oxide, the crystallization parameter P obtained by formula (1) is 0.7 or more.　(1): P = (2 × Ic + Im)/(Ic + Im + Ia)

Description

光学フィルタ及び殺菌装置Optical filters and sterilizers
　本発明は、特定の波長域の光を選択的に透過させることのできる、光学フィルタ及び該光学フィルタを用いた殺菌装置に関する。 The present invention relates to an optical filter capable of selectively transmitting light in a specific wavelength range and a sterilization device using the optical filter.
　従来、特定の波長域の光を選択的に透過させることのできる光学フィルタが、種々の用途で広く用いられている。このような光学フィルタとしては、誘電体膜を用いたバンドパスフィルタが知られている。 Conventionally, optical filters capable of selectively transmitting light in a specific wavelength range have been widely used for various purposes. As such an optical filter, a bandpass filter using a dielectric film is known.
　例えば、下記の特許文献１には、波長２５０ｎｍ以下の特定の紫外光に対して透過率が最大となるように形成されたバンドパスフィルタが開示されている。特許文献１のバンドパスフィルタでは、誘電体膜からなるキャビティ層の上下が金属薄膜により被覆されている。特許文献１では、上記金属薄膜が、バンドパスフィルタにおける可視域の波長の光の透過率が１０％以下となる膜厚であることが記載されている。また、上記キャビティ層が、誘電体膜からなる層であり、誘電体としては、二酸化ケイ素、フッ化ランタン、フッ化マグネシウム、酸化アルミニウム、酸化ハフニウム等が用いられることが記載されている。 For example, Patent Document 1 below discloses a band-pass filter formed so as to maximize the transmittance of specific ultraviolet light with a wavelength of 250 nm or less. In the bandpass filter of Patent Document 1, the top and bottom of the cavity layer made of the dielectric film are covered with metal thin films. Patent Literature 1 describes that the metal thin film has a film thickness such that the transmittance of light in the visible region in a band-pass filter is 10% or less. Further, it is described that the cavity layer is a layer made of a dielectric film, and that silicon dioxide, lanthanum fluoride, magnesium fluoride, aluminum oxide, hafnium oxide, etc. are used as the dielectric.
特開２０１３－０６８８８５号公報JP 2013-068885 A
　ところで、皮膚等についた細菌やウイルスの殺菌処理などの紫外線による殺菌処理においては、波長２２０ｎｍ～２２５ｎｍの紫外線を発光するエキシマランプなどが用いられている。しかしながら、エキシマランプにおいては、人体に有害な波長２４０ｎｍ～３２０ｎｍの紫外線もわずかに発光するという問題がある。 By the way, excimer lamps that emit ultraviolet rays with a wavelength of 220 nm to 225 nm are used for sterilization treatment using ultraviolet rays, such as sterilization treatment of bacteria and viruses on the skin. However, excimer lamps have the problem that even a small amount of ultraviolet light with a wavelength of 240 nm to 320 nm, which is harmful to the human body, is emitted.
　特許文献１のようなバンドパスフィルタを用いた場合においても、このような波長２４０ｎｍ～３２０ｎｍにおける紫外線の透過を十分に抑制することが困難であった。特に、波長２４０ｎｍ～３２０ｎｍにおける紫外線の透過を抑制しようとすると、一方で波長２２０ｎｍ～２２５ｎｍにおける紫外線を十分に透過させ難くなることから、人体に有害な紫外線の透過の抑制と、殺菌処理に有用な紫外線の高効率な透過とを高いレベルで両立することが難しいという問題がある。 Even in the case of using a band-pass filter as in Patent Document 1, it was difficult to sufficiently suppress the transmission of such ultraviolet rays with wavelengths of 240 nm to 320 nm. In particular, when trying to suppress the transmission of ultraviolet rays with a wavelength of 240 nm to 320 nm, it is difficult to sufficiently transmit ultraviolet rays with a wavelength of 220 nm to 225 nm. There is a problem that it is difficult to achieve a high level of both high-efficiency transmission of ultraviolet rays.
　本発明の目的は、波長２４０ｎｍ～３２０ｎｍにおける紫外線の透過を抑制しつつ、波長２２０ｎｍ～２２５ｎｍにおける紫外線を効果的に透過させることができる、光学フィルタ及び該光学フィルタを用いた殺菌装置を提供することにある。 An object of the present invention is to provide an optical filter that can effectively transmit ultraviolet rays with a wavelength of 220 nm to 225 nm while suppressing transmission of ultraviolet rays with a wavelength of 240 nm to 320 nm, and a sterilization device using the optical filter. It is in.
　上記課題を解決する光学フィルタ及び殺菌装置の各態様について説明する。 Each aspect of the optical filter and the sterilization device that solves the above problems will be explained.
　本発明の態様１に係る光学フィルタは、透明基材と、前記透明基材上に設けられており、酸化ハフニウムを含む、誘電体多層膜とを備え、Ｘ線回折測定において、立方晶系酸化ハフニウム結晶に由来する（１　１　１）結晶面による回折ピークの回折強度をＩｃとし、単斜晶系酸化ハフニウム結晶に由来する（－１　１　１）結晶面による回折ピークの回折強度をＩｍとし、非晶質酸化ハフニウムに由来する回折ピークの回折強度をＩａとしたときに、下記式（１）における結晶化パラメータＰが、０．７以上であることを特徴としている。 An optical filter according to aspect 1 of the present invention includes a transparent base material and a dielectric multilayer film provided on the transparent base material and containing hafnium oxide. Let I c be the diffraction intensity of the diffraction peak due to the (1 1 1) crystal face derived from the hafnium crystal, and I m be the diffraction intensity of the diffraction peak due to the (-1 1 1) crystal face derived from the monoclinic hafnium oxide crystal. and the crystallization parameter P in the following formula (1) is 0.7 or more, where Ia is the diffraction intensity of the diffraction peak derived from amorphous hafnium oxide.
　Ｐ＝（２×Ｉｃ＋Ｉｍ）／（Ｉｃ＋Ｉｍ＋Ｉａ）…式（１） P=(2× Ic + Im )/( Ic + Im + Ia ) Equation (1)
　本発明の態様２に係る光学フィルタは、透明基材と、前記透明基材上に設けられており、酸化ハフニウムを含む、誘電体多層膜とを備え、ＣｕＫα線を用いたＸ線回折測定において、回折角２θ＝３０．３°±０．７゜の範囲内に存在する結晶回折ピークの回折強度をＩｃとし、回折角２θ＝２８．４°±０．５゜の範囲内に存在する結晶回折ピークの回折強度をＩｍとし、回折角２θ＝３０．０°±２．０゜の範囲内に存在する非晶質回折ピークの回折強度をＩａとしたときに、下記式（１）における結晶化パラメータＰが、０．７以上であることを特徴としている。 An optical filter according to aspect 2 of the present invention includes a transparent substrate and a dielectric multilayer film provided on the transparent substrate and containing hafnium oxide, and in X-ray diffraction measurement using CuKα rays, , the diffraction intensity of the crystal diffraction peak existing within the range of the diffraction angle 2θ = 30.3° ± 0.7° is defined as Ic , and the diffraction intensity exists within the range of the diffraction angle 2θ = 28.4° ± 0.5°. When the diffraction intensity of the crystal diffraction peak is Im and the diffraction intensity of the amorphous diffraction peak existing within the diffraction angle 2θ = 30.0° ± 2.0° is Ia, the following formula (1) is obtained. is characterized by a crystallization parameter P of 0.7 or more.
　Ｐ＝（２×Ｉｃ＋Ｉｍ）／（Ｉｃ＋Ｉｍ＋Ｉａ）…式（１） P=(2× Ic + Im )/( Ic + Im + Ia ) Equation (1)
　態様３に係る光学フィルタは、態様１又は態様２において、前記誘電体多層膜が、相対的に屈折率が高い高屈折率膜と、相対的に屈折率が低い低屈折率膜とを有し、前記高屈折率膜が、前記酸化ハフニウムを含む膜であることが好ましい。 An optical filter according to Aspect 3 is Aspect 1 or 2, wherein the dielectric multilayer film includes a high refractive index film having a relatively high refractive index and a low refractive index film having a relatively low refractive index. , the high refractive index film is preferably a film containing the hafnium oxide.
　態様４に係る光学フィルタは、態様３において、前記低屈折率膜が、酸化ケイ素を含む膜であることが好ましい。 In the optical filter according to Aspect 4, in Aspect 3, it is preferable that the low refractive index film is a film containing silicon oxide.
　態様５に係る光学フィルタは、態様１から態様４のいずれか一つの態様において、入射角０°において、波長２２０ｎｍ～２２５ｎｍにおける分光透過率の最小値が、５０％以上であり、入射角０°において、波長２４０ｎｍ～３２０ｎｍにおける分光透過率の最大値が、５％以下であることが好ましい。 In any one of Aspects 1 to 4, the optical filter according to Aspect 5 has a minimum spectral transmittance of 50% or more at a wavelength of 220 nm to 225 nm at an incident angle of 0°. , the maximum spectral transmittance at a wavelength of 240 nm to 320 nm is preferably 5% or less.
　本発明の態様６に係る殺菌装置は、処理対象微生物を不活化処理するための殺菌装置であって、放出光の波長が、波長１９０ｎｍ～２３０ｎｍの波長域に存在する、光源と、態様１から態様５のいずれか一つの態様の光学フィルタとを備えることを特徴としている。 A sterilization device according to aspect 6 of the present invention is a sterilization device for inactivating microorganisms to be treated, wherein the wavelength of emitted light is in the wavelength range of 190 nm to 230 nm, and from aspect 1 and the optical filter according to any one of mode 5.
　本発明によれば、波長２４０ｎｍ～３２０ｎｍにおける紫外線の透過を抑制しつつ、波長２２０ｎｍ～２２５ｎｍにおける紫外線を効果的に透過させることができる、光学フィルタ及び該光学フィルタを用いた殺菌装置を提供することができる。 According to the present invention, an optical filter and a sterilization device using the optical filter are provided that can effectively transmit ultraviolet rays with a wavelength of 220 nm to 225 nm while suppressing transmission of ultraviolet rays with a wavelength of 240 nm to 320 nm. can be done.
図１は、本発明の第１の実施形態に係る光学フィルタを示す模式的断面図である。FIG. 1 is a schematic cross-sectional view showing an optical filter according to the first embodiment of the invention. 図２は、本発明の第２の実施形態に係る光学フィルタを示す模式的断面図である。FIG. 2 is a schematic cross-sectional view showing an optical filter according to a second embodiment of the invention. 図３は、本発明の一実施形態に係る殺菌装置を示す模式図である。FIG. 3 is a schematic diagram showing a sterilization device according to one embodiment of the present invention. 図４は、実施例２及び比較例１で得られた光学フィルタのＸ線回折スペクトルを示す図である。4 is a diagram showing X-ray diffraction spectra of the optical filters obtained in Example 2 and Comparative Example 1. FIG. 図５は、実施例２及び比較例１で得られた光学フィルタの透過スペクトルを示す図である。5 is a diagram showing transmission spectra of the optical filters obtained in Example 2 and Comparative Example 1. FIG. 図６は、実施例１～１６及び比較例１～４における結晶化パラメータＰと、波長２２０ｎｍ～２２５ｎｍにおける分光透過率の最小値との関係を示すグラフである。FIG. 6 is a graph showing the relationship between the crystallization parameter P in Examples 1 to 16 and Comparative Examples 1 to 4 and the minimum value of spectral transmittance at wavelengths of 220 nm to 225 nm.
　以下、好ましい実施形態について説明する。但し、以下の実施形態は単なる例示であり、本発明は以下の実施形態に限定されるものではない。また、各図面において、実質的に同一の機能を有する部材は同一の符号で参照する場合がある。 A preferred embodiment will be described below. However, the following embodiments are merely examples, and the present invention is not limited to the following embodiments. Also, in each drawing, members having substantially the same function may be referred to by the same reference numerals.
　［第１の実施形態］
　（光学フィルタ）
　図１は、本発明の第１の実施形態に係る光学フィルタを示す模式的断面図である。図１に示すように、光学フィルタ１は、透明基材２と、誘電体多層膜３とを備える。透明基材２上に、誘電体多層膜３が設けられている。 [First embodiment]
(optical filter)
FIG. 1 is a schematic cross-sectional view showing an optical filter according to the first embodiment of the invention. As shown in FIG. 1, an optical filter 1 includes a transparent base material 2 and a dielectric multilayer film 3 . A dielectric multilayer film 3 is provided on a transparent substrate 2 .
　本実施形態において、透明基材２は、矩形板状の形状を有する。もっとも、透明基材２は、例えば、円板状等の形状を有していてもよく、その形状は特に限定されない。 In this embodiment, the transparent substrate 2 has a rectangular plate shape. However, the transparent base material 2 may have, for example, a disk-like shape, and the shape is not particularly limited.
　透明基材２の厚みは、特に限定されず、光透過率などに応じて適宜設定することができる。透明基材２の厚みは、例えば、０．１ｍｍ～３０ｍｍ程度とすることができる。 The thickness of the transparent base material 2 is not particularly limited, and can be appropriately set according to the light transmittance and the like. The thickness of the transparent substrate 2 can be, for example, about 0.1 mm to 30 mm.
　透明基材２は、光学フィルタ１の使用波長域で透明な基材であることが好ましい。より具体的には、透明基材２は、波長２２０ｎｍ～２２５ｎｍにおける紫外波長域の平均光透過率が８０％以上であることが好ましい。 The transparent base material 2 is preferably a base material that is transparent in the wavelength range used by the optical filter 1 . More specifically, the transparent base material 2 preferably has an average light transmittance of 80% or more in the ultraviolet wavelength region at a wavelength of 220 nm to 225 nm.
　透明基材２の材料としては、特に限定されず、例えば、ガラス、樹脂等が挙げられる。ガラスとしては、石英ガラス、ホウケイ酸ガラス等が挙げられる。石英ガラスは、合成石英ガラスであってもよく、溶融石英ガラスであってもよい。ホウケイ酸ガラスは、ガラス組成として、質量％で、ＳｉＯ２　５５％～７５％、Ａｌ２Ｏ３　１．０％～１０％、Ｂ２Ｏ３　１０％～３０％、ＣａＯ　０％～５％、ＢａＯ　０％～５％、Ｌｉ２Ｏ＋Ｎａ２Ｏ＋Ｋ２Ｏ　１．０％～１５％を含有することが好ましく、さらには、ＴｉＯ２　０％～０．００１％、Ｆｅ２Ｏ３　０％～０．００１％、Ｆ　０．５％～２．０％を含有することがより好ましい。 The material of the transparent substrate 2 is not particularly limited, and examples thereof include glass and resin. Examples of glass include quartz glass and borosilicate glass. The quartz glass may be synthetic quartz glass or fused quartz glass. Borosilicate glass has a glass composition of 55% to 75% by mass, SiO 2 55% to 75%, Al 2 O 3 1.0% to 10%, B 2 O 3 10% to 30%, CaO 0% to 5%, It preferably contains 0% to 5% BaO, 1.0% to 15% Li 2 O+Na 2 O+K 2 O, and further contains 0% to 0.001% TiO 2 and 0% to 0.001% Fe 2 O 3 . 001% and F 0.5% to 2.0%.
　透明基材２は、対向している第１の主面２ａ及び第２の主面２ｂを有する。透明基材２の第１の主面２ａ上には、フィルタ部としての誘電体多層膜３が設けられている。 The transparent substrate 2 has a first major surface 2a and a second major surface 2b facing each other. A dielectric multilayer film 3 is provided as a filter section on the first main surface 2a of the transparent base material 2 .
　誘電体多層膜３は、相対的に屈折率が高い高屈折率膜４と相対的に屈折率が低い低屈折率膜５とを有する、多層膜である。本実施形態では、透明基材２の第１の主面２ａ上に、高屈折率膜４及び低屈折率膜５がこの順に交互に積層されることにより、多層膜が構成されている。 The dielectric multilayer film 3 is a multilayer film having a high refractive index film 4 with a relatively high refractive index and a low refractive index film 5 with a relatively low refractive index. In this embodiment, a multilayer film is configured by alternately laminating the high refractive index film 4 and the low refractive index film 5 on the first main surface 2a of the transparent substrate 2 in this order.
　高屈折率膜４は、酸化ハフニウムにより構成されており、酸化ハフニウムを主成分とする膜である。 The high refractive index film 4 is composed of hafnium oxide, and is a film containing hafnium oxide as its main component.
　また、低屈折率膜５は、酸化ケイ素により構成されており、酸化ケイ素を主成分とする膜である。もっとも、低屈折率膜５は、酸化アルミニウム、酸化ジルコニウム、フッ化マグネシウム、又は窒化ケイ素等を主成分とする膜であってもよい。これらの低屈折率膜５の材料は、１種を単独で用いてもよく、複数種を併用してもよい。 In addition, the low refractive index film 5 is composed of silicon oxide and is a film containing silicon oxide as a main component. However, the low refractive index film 5 may be a film whose main component is aluminum oxide, zirconium oxide, magnesium fluoride, silicon nitride, or the like. One of these materials for the low refractive index film 5 may be used alone, or two or more of them may be used in combination.
　なお、本明細書において、主成分とする膜とは、膜中にその材料が５０質量％以上含まれている膜のことをいうものとする。主成分とする膜においては、膜中にその材料が８０質量％以上含まれていることが好ましく、９０質量％以上含まれていることがより好ましい。当然ながら、主成分とする膜は、膜中にその材料を１００質量％含む膜であってもよい。 In this specification, a film containing the material as a main component means a film containing 50% by mass or more of the material. The film containing the material as the main component preferably contains 80% by mass or more of the material, more preferably 90% by mass or more. Of course, the main component film may be a film containing 100% by weight of the material in the film.
　本実施形態の光学フィルタ１は、Ｘ線回折測定において、立方晶系酸化ハフニウム結晶に由来する（１　１　１）結晶面による回折ピークの回折強度をＩｃとし、単斜晶系酸化ハフニウム結晶に由来する（－１　１　１）結晶面による回折ピークの回折強度をＩｍとし、非晶質酸化ハフニウムに由来する回折ピークの回折強度をＩａとしたときに、下記式（１）における結晶化パラメータＰが、０．７以上である。 In the X-ray diffraction measurement, the optical filter 1 of the present embodiment has the diffraction intensity of the diffraction peak due to the (1 1 1) crystal plane derived from the cubic hafnium oxide crystal, and the diffraction intensity of the diffraction peak is Ic . When the diffraction intensity of the diffraction peak due to the derived (−1 1 1) crystal plane is I m and the diffraction intensity of the diffraction peak derived from amorphous hafnium oxide is I a , the crystallization in the following formula (1) Parameter P is 0.7 or more.
　また、本実施形態の光学フィルタ１は、ＣｕＫα線を用いたＸ線回折測定において、回折角２θ＝３０．３°±０．７゜の範囲内に存在する結晶回折ピークの回折強度をＩｃとし、回折角２θ＝２８．４°±０．５゜の範囲内に存在する結晶回折ピークの回折強度をＩｍとし、回折角２θ＝３０．０°±２．０゜の範囲内に存在する非晶質回折ピークの回折強度をＩａとしたときに、下記式（１）における結晶化パラメータＰが、０．７以上であってもよい。 Further, in the X-ray diffraction measurement using CuKα rays, the optical filter 1 of the present embodiment has the diffraction intensity of the crystal diffraction peak existing within the range of the diffraction angle 2θ=30.3°±0.7° as I c Let Im be the diffraction intensity of the crystal diffraction peak existing within the range of the diffraction angle 2θ = 28.4° ± 0.5°, and exist within the range of the diffraction angle 2θ = 30.0° ± 2.0°. The crystallization parameter P in the following formula (1) may be 0.7 or more, where Ia is the diffraction intensity of the amorphous diffraction peak.
　Ｐ＝（２×Ｉｃ＋Ｉｍ）／（Ｉｃ＋Ｉｍ＋Ｉａ）…式（１） P=(2× Ic + Im )/( Ic + Im + Ia ) Equation (1)
　なお、本明細書において、Ｘ線回折測定は、広角Ｘ線回折法によって測定することができる。Ｘ線回折装置としては、例えば、リガク社製、品番「ＳｍａｒｔＬａｂ」を用いることができる。また、線源としては、ＣｕＫα線を用いることができる。なお、Ｘ線回折測定においては、光学フィルタ１全体を光学フィルタ１の主面１ａ側から測定に供するものとする。 In addition, in this specification, the X-ray diffraction measurement can be performed by a wide-angle X-ray diffraction method. As the X-ray diffractometer, for example, Rigaku's product number "SmartLab" can be used. Moreover, CuKα rays can be used as the radiation source. In the X-ray diffraction measurement, the entire optical filter 1 is measured from the main surface 1a side of the optical filter 1. FIG.
　また、回折強度Ｉｃ、回折強度Ｉｍ、及び回折強度Ｉａは、以下のようにして求めることができる。 Also, the diffraction intensity I c , the diffraction intensity I m , and the diffraction intensity I a can be obtained as follows.
　まず、上記のようにして測定した光学フィルタ１のＸ線回折プロファイルにおいて、２θ＝１０°及び２θ＝４０°の端点を結ぶ直線をバックグラウンドとして除去する。次に、バックグラウンドを除去したＸ線回折プロファイルにおいて、初期条件として、２θ＝２８°付近に単斜晶系酸化ハフニウム結晶に由来する（－１　１　１）結晶面によるフィッティング用ピークを設定する。２θ＝３０°付近に立方晶系酸化ハフニウム結晶に由来する（１　１　１）結晶面によるフィッティング用ピークを設定する。２θ＝２８°～３２°の範囲に非晶質酸化ハフニウムに由来するフィッティング用ピークを設定する。また、２θ＝２０°～２５°の範囲に透明基材２に由来するフィッティング用ピークを設定する。なお、酸化ハフニウム結晶に由来するその他の結晶面によるピークや、低屈折率膜５に由来する酸化ハフニウム結晶以外のピークが存在する場合は、適宜対応するフィッティング用ピークを設定するものとする。 First, in the X-ray diffraction profile of the optical filter 1 measured as described above, a straight line connecting the end points of 2θ=10° and 2θ=40° is removed as the background. Next, in the X-ray diffraction profile from which the background has been removed, as an initial condition, a peak for fitting due to the (−1 1 1) crystal plane derived from the monoclinic hafnium oxide crystal is set near 2θ=28°. A fitting peak due to the (111) crystal plane derived from the cubic hafnium oxide crystal is set near 2θ=30°. A fitting peak derived from amorphous hafnium oxide is set in the range of 2θ=28° to 32°. Also, a fitting peak derived from the transparent substrate 2 is set in the range of 2θ=20° to 25°. If there are peaks due to other crystal planes derived from the hafnium oxide crystals or peaks other than the hafnium oxide crystals derived from the low refractive index film 5, the corresponding fitting peaks are appropriately set.
　なお、フィッティング関数としては、擬フォークト関数（ｐｓｅｕｄｏ－Ｖｏｉｇｔ　ｆｕｎｃｔｉｏｎ）を使用する。また、非線形最小二乗法により、実測のＸ線回折プロファイルと各フィッティング用ピークの合成プロファイルとの間の残差二乗和が最小となるように、各フィッティング用ピークの回折角（２θ）、半値全幅（ＦＷＨＭ）、積分強度（Ｉ）、及びローレンツ関数（Ｌｏｒｅｎｔｚｉａｎ　ｆｕｎｃｔｉｏｎ）とガウス関数（Ｇａｕｓｓｉａｎ　ｆｕｎｃｔｉｏｎ）の混合比を最適化する。そして、最適なフィッティング結果が得られた際の単斜晶系酸化ハフニウム結晶に由来する（－１　１　１）結晶面による回折ピークの積分強度を回折強度Ｉｍとし、立方晶系酸化ハフニウム結晶に由来する（１　１　１）結晶面による回折ピークの積分強度を回折強度Ｉｃとし、非晶質酸化ハフニウムに由来する回折ピークの積分強度を回折強度Ｉａとする。なお、上記のようなピークフィッティングは、例えば、リガク社製、品番「ＰＤＸＬ」を用いて行うことができる。 A pseudo-Voigt function is used as the fitting function. Further, by the nonlinear least squares method, the diffraction angle (2θ) and the full width at half maximum of each fitting peak are determined so that the residual sum of squares between the measured X-ray diffraction profile and the combined profile of each fitting peak is minimized. (FWHM), the integrated intensity (I), and the mixture ratio of the Lorentzian and Gaussian functions are optimized. Then, the integrated intensity of the diffraction peak due to the (−1 1 1) crystal plane derived from the monoclinic hafnium oxide crystal when the optimum fitting result is obtained is defined as the diffraction intensity Im , and the cubic hafnium oxide crystal is The integrated intensity of the diffraction peak due to the (1 1 1) crystal plane derived from the crystal is defined as the diffraction intensity Ic , and the integrated intensity of the diffraction peak derived from the amorphous hafnium oxide is defined as the diffraction intensity Ia . The peak fitting as described above can be performed using, for example, product number "PDXL" manufactured by Rigaku.
　本実施形態の光学フィルタ１は、上記の構成を備えるので、波長２４０ｎｍ～３２０ｎｍにおける紫外線の透過を抑制しつつ、波長２２０ｎｍ～２２５ｎｍにおける紫外線を効果的に透過させることができる。 Since the optical filter 1 of the present embodiment has the above configuration, it is possible to effectively transmit ultraviolet rays with a wavelength of 220 nm to 225 nm while suppressing transmission of ultraviolet rays with a wavelength of 240 nm to 320 nm.
　従来、エキシマランプ等においては、人体に有害な波長２４０ｎｍ～３２０ｎｍの紫外線もわずかに発光するという問題があった。特に、波長２４０ｎｍ～３２０ｎｍにおける紫外線の透過を抑制しようとすると、一方で波長２２０ｎｍ～２２５ｎｍにおける紫外線を十分に透過させ難くなることから、人体に有害な紫外線の透過の抑制と、殺菌処理に有用な紫外線の高効率な透過とを高いレベルで両立することが難しいという問題があった。 Conventionally, excimer lamps and the like had the problem of emitting a small amount of ultraviolet light with a wavelength of 240 nm to 320 nm, which is harmful to the human body. In particular, when trying to suppress the transmission of ultraviolet rays with a wavelength of 240 nm to 320 nm, it is difficult to sufficiently transmit ultraviolet rays with a wavelength of 220 nm to 225 nm. There is a problem that it is difficult to achieve a high level of both high-efficiency transmission of ultraviolet rays.
　これに対して、本発明者は、上述のＸ線回折測定で得られる上記式（１）における結晶化パラメータＰに着目し、該結晶化パラメータＰを０．７以上とすることにより、波長２４０ｎｍ～３２０ｎｍにおける紫外線の透過を抑制しつつ、波長２２０ｎｍ～２２５ｎｍにおける紫外線を効果的に透過させることができることを見出した。なお、この結晶化パラメータＰと透過率との相関は、後述の実施例の欄における図６からも確認することができる。 On the other hand, the present inventors focused on the crystallization parameter P in the above formula (1) obtained by the above-described X-ray diffraction measurement, and set the crystallization parameter P to 0.7 or more to obtain a wavelength of 240 nm. It was found that ultraviolet rays with a wavelength of 220 nm to 225 nm can be effectively transmitted while suppressing transmission of ultraviolet rays with wavelengths of up to 320 nm. The correlation between the crystallization parameter P and the transmittance can also be confirmed from FIG. 6 in the section of Examples described later.
　本発明において、上述のＸ線回折測定で得られる上記式（１）における結晶化パラメータＰは、好ましくは０．８以上、より好ましくは０．９以上、さらに好ましくは１．０以上であり、好ましくは２．０以下、より好ましくは１．８以下、さらに好ましくは１．５以下である。結晶化パラメータＰが上記範囲内にある場合、波長２４０ｎｍ～３２０ｎｍにおける紫外線の透過をより一層確実に抑制しつつ、波長２２０ｎｍ～２２５ｎｍにおける紫外線をより一層効果的に透過させることができる。 In the present invention, the crystallization parameter P in the above formula (1) obtained by the above X-ray diffraction measurement is preferably 0.8 or more, more preferably 0.9 or more, still more preferably 1.0 or more, It is preferably 2.0 or less, more preferably 1.8 or less, still more preferably 1.5 or less. When the crystallization parameter P is within the above range, the transmission of ultraviolet rays with a wavelength of 240 nm to 320 nm can be more reliably suppressed, and the ultraviolet rays with a wavelength of 220 nm to 225 nm can be more effectively transmitted.
　このように、本実施形態の光学フィルタ１は、光の干渉で特定の波長域の光を選択的に透過させるように設計されたバンドパスフィルタである。 Thus, the optical filter 1 of this embodiment is a bandpass filter designed to selectively transmit light in a specific wavelength range by light interference.
　具体的には、光学フィルタ１は、波長２２０ｎｍ～２２５ｎｍにおける分光透過率の最小値が、好ましくは５０％以上、より好ましくは６０％以上、さらに好ましくは７０％以上である。この場合、皮膚などの殺菌処理に有用な紫外線をより一層効果的に透過させることができる。なお、波長２２０ｎｍ～２２５ｎｍにおける分光透過率の最小値の上限値は、特に限定されないが、例えば、９５％とすることができる。 Specifically, the optical filter 1 has a minimum spectral transmittance of preferably 50% or more, more preferably 60% or more, and even more preferably 70% or more at a wavelength of 220 nm to 225 nm. In this case, ultraviolet rays useful for sterilizing the skin can be transmitted more effectively. Although the upper limit of the minimum value of the spectral transmittance at wavelengths of 220 nm to 225 nm is not particularly limited, it can be set to 95%, for example.
　また、光学フィルタ１は、波長２４０ｎｍ～３２０ｎｍにおける分光透過率の最大値が、好ましくは５％以下、より好ましくは３％以下、さらに好ましくは２．５％以下、特に好ましくは１％以下である。この場合、人体に有害な紫外線の透過をより一層効果的に抑制させることができる。なお、波長２４０ｎｍ～３２０ｎｍにおける分光透過率の最大値の下限値は、特に限定されないが、例えば、０．２％とすることができる。 In addition, the optical filter 1 preferably has a maximum spectral transmittance of 5% or less, more preferably 3% or less, still more preferably 2.5% or less, and particularly preferably 1% or less at a wavelength of 240 nm to 320 nm. . In this case, transmission of ultraviolet rays harmful to the human body can be more effectively suppressed. Although the lower limit of the maximum spectral transmittance at wavelengths of 240 nm to 320 nm is not particularly limited, it can be set to 0.2%, for example.
　本明細書において、分光透過率は、例えば、分光光度計（日立ハイテクサイエンス社製、品番「ＵＨ４１５０」）を用いて光学フィルタ１全体の分光透過率を測定することにより求めることができる。測定条件としては、例えば、光学フィルタ１の主面１ａ側から測定し、入射角を０°とし、測定波長を１９０ｎｍ～４００ｎｍとして測定することができる。なお、入射角は、光学フィルタ１の主面１ａに沿う方向に直交する誘電体多層膜３の積層方向（厚み方向）を法線方向としたときに、法線方向に対して傾斜した角度を意味するものとする（例えば、図１のθ）。従って、法線方向に沿う方向が、入射角０°となる。 In this specification, the spectral transmittance can be obtained, for example, by measuring the spectral transmittance of the entire optical filter 1 using a spectrophotometer (manufactured by Hitachi High-Tech Science, product number "UH4150"). As for the measurement conditions, for example, measurement can be performed from the main surface 1a side of the optical filter 1, with an incident angle of 0° and a measurement wavelength of 190 nm to 400 nm. The incident angle is defined as an angle inclined with respect to the normal direction of the stacking direction (thickness direction) of the dielectric multilayer film 3 perpendicular to the direction along the main surface 1a of the optical filter 1. (eg, θ in FIG. 1). Therefore, the direction along the normal direction has an incident angle of 0°.
　このように、光学フィルタ１では、波長２２０ｎｍ～２２５ｎｍにおける紫外線の透過性に優れるので、皮膚などの殺菌処理に有用な紫外線を効果的に透過させることができる。また、光学フィルタ１では、波長２４０ｎｍ～３２０ｎｍにおける紫外線の透過を抑制できるので、人体に有害な紫外線の透過を抑制することができる。 As described above, the optical filter 1 has excellent transmittance of ultraviolet rays having a wavelength of 220 nm to 225 nm, so that ultraviolet rays useful for sterilizing the skin can be effectively transmitted. In addition, since the optical filter 1 can suppress the transmission of ultraviolet rays having a wavelength of 240 nm to 320 nm, it is possible to suppress the transmission of ultraviolet rays that are harmful to the human body.
　従って、本実施形態の光学フィルタ１によれば、例えば、エキシマランプ等の紫外線照射装置に用いた場合に、人体に有害な紫外線の透過を抑制しつつ、殺菌処理に有用な紫外線を効果的に透過させることができる。 Therefore, according to the optical filter 1 of the present embodiment, for example, when used in an ultraviolet irradiation device such as an excimer lamp, it is possible to effectively emit ultraviolet rays useful for sterilization while suppressing transmission of ultraviolet rays harmful to the human body. can be permeated.
　本発明において、高屈折率膜４の１層当たりの厚みは、特に限定されないが、好ましくは５ｎｍ以上、より好ましくは１０ｎｍ以上、好ましくは６０ｎｍ以下、より好ましくは５０ｎｍ以下である。 In the present invention, the thickness of one layer of the high refractive index film 4 is not particularly limited, but is preferably 5 nm or more, more preferably 10 nm or more, preferably 60 nm or less, and more preferably 50 nm or less.
　高屈折率膜４の総厚みｔＨは、好ましくは２５０ｎｍ以上、より好ましくは３００ｎｍ以上、さらに好ましくは４００ｎｍ以上、特に好ましくは５００ｎｍ以上であり、好ましくは１０００ｎｍ以下、より好ましくは８００ｎｍ以下、さらに好ましくは７００ｎｍ以下、特に好ましくは６００ｎｍ以下である。高屈折率膜４の総厚みｔＨが、上記下限値以上である場合、波長２２０ｎｍ～２２５ｎｍにおける紫外線をより一層効果的に透過させることができる。また、波長２４０ｎｍ～３２０ｎｍにおける紫外線の透過をより一層抑制することができる。一方、高屈折率膜４の総厚みｔＨが、上記上限値以下である場合、波長２２０ｎｍ～２２５ｎｍにおける紫外線をより一層効果的に透過させることができる。 The total thickness tH of the high refractive index film 4 is preferably 250 nm or more, more preferably 300 nm or more, still more preferably 400 nm or more, particularly preferably 500 nm or more, preferably 1000 nm or less, more preferably 800 nm or less, and even more preferably. is 700 nm or less, particularly preferably 600 nm or less. When the total thickness tH of the high refractive index film 4 is equal to or greater than the above lower limit, it is possible to more effectively transmit ultraviolet rays having a wavelength of 220 nm to 225 nm. In addition, transmission of ultraviolet rays having a wavelength of 240 nm to 320 nm can be further suppressed. On the other hand, when the total thickness tH of the high refractive index film 4 is equal to or less than the above upper limit, it is possible to more effectively transmit ultraviolet rays with a wavelength of 220 nm to 225 nm.
　低屈折率膜５の１層当たりの厚みは、特に限定されないが、好ましくは５ｎｍ以上、より好ましくは１０ｎｍ以上、好ましくは８０ｎｍ以下、より好ましくは６０ｎｍ以下である。 The thickness per layer of the low refractive index film 5 is not particularly limited, but is preferably 5 nm or more, more preferably 10 nm or more, preferably 80 nm or less, and more preferably 60 nm or less.
　低屈折率膜５の総厚みｔＬは、好ましくは５００ｎｍ以上、より好ましくは６００ｎｍ以上、さらに好ましくは７００ｎｍ以上、特に好ましくは８００ｎｍ以上であり、好ましくは２０００ｎｍ以下、より好ましくは１７００ｎｍ以下、さらに好ましくは１５００ｎｍ以下、特に好ましくは１４００ｎｍ以下である。低屈折率膜５の総厚みｔＬが、上記下限値以上である場合、波長２４０ｎｍ～３２０ｎｍにおける紫外線の透過をより一層抑制することができる。一方、低屈折率膜５の総厚みｔＬが、上記上限値以下である場合、波長２２０ｎｍ～２２５ｎｍにおける紫外線をより一層効果的に透過させることができる。 The total thickness t L of the low refractive index film 5 is preferably 500 nm or more, more preferably 600 nm or more, still more preferably 700 nm or more, particularly preferably 800 nm or more, preferably 2000 nm or less, more preferably 1700 nm or less, and even more preferably. is 1500 nm or less, particularly preferably 1400 nm or less. When the total thickness t L of the low refractive index film 5 is equal to or greater than the above lower limit, transmission of ultraviolet rays having a wavelength of 240 nm to 320 nm can be further suppressed. On the other hand, when the total thickness t L of the low refractive index film 5 is equal to or less than the above upper limit, it is possible to more effectively transmit ultraviolet rays with a wavelength of 220 nm to 225 nm.
　高屈折率膜４の総厚みｔＨと、低屈折率膜５の総厚みｔＬとの比（ｔＨ／ｔＬ）は、好ましくは０．２以上、より好ましくは０．３以上、さらに好ましくは０．４以上、特に好ましくは０．５以上、最も好ましくは０．６以上であり、好ましくは１以下、より好ましくは０．９以下、さらに好ましくは０．８以下、特に好ましくは０．７５以下である。比（ｔＨ／ｔＬ）が、上記下限値以上である場合、波長２２０ｎｍ～２２５ｎｍにおける紫外線をより一層効果的に透過させることができる。また、比（ｔＨ／ｔＬ）が、上記上限値以下である場合、波長２４０ｎｍ～３２０ｎｍにおける紫外線の透過をより一層抑制することができる。 The ratio ( tH / tL ) between the total thickness tH of the high refractive index film 4 and the total thickness tL of the low refractive index film 5 is preferably 0.2 or more, more preferably 0.3 or more, and further Preferably 0.4 or more, particularly preferably 0.5 or more, most preferably 0.6 or more, preferably 1 or less, more preferably 0.9 or less, still more preferably 0.8 or less, particularly preferably 0 0.75 or less. When the ratio (t H /t L ) is equal to or higher than the above lower limit, ultraviolet rays with a wavelength of 220 nm to 225 nm can be transmitted more effectively. Further, when the ratio (t H /t L ) is equal to or less than the above upper limit, transmission of ultraviolet rays with a wavelength of 240 nm to 320 nm can be further suppressed.
　誘電体多層膜３の総厚みとしては、特に限定されないが、好ましくは８００ｎｍ以上、より好ましくは１０００ｎｍ以上、さらに好ましくは１１００ｎｍ以上、特に好ましくは１２００ｎｍ以上、最も好ましくは１５００ｎｍ以上、好ましくは３０００ｎｍ以下、より好ましくは２５００ｎｍ以下、さらに好ましくは２２００ｎｍ以下、特に好ましくは２０００ｎｍ以下、最も好ましくは１９００ｎｍ以下である。誘電体多層膜３の総厚みが上記下限値以上である場合、波長２２０ｎｍ～２２５ｎｍにおける紫外線をより一層効果的に透過させることができる。また、波長２４０ｎｍ～３２０ｎｍにおける紫外線の透過をより一層抑制することができる。一方、誘電体多層膜３の総厚みが上記上限値以下である場合、波長２２０ｎｍ～２２５ｎｍにおける紫外線をより一層効果的に透過させることができる。 The total thickness of the dielectric multilayer film 3 is not particularly limited, but is preferably 800 nm or more, more preferably 1000 nm or more, still more preferably 1100 nm or more, particularly preferably 1200 nm or more, most preferably 1500 nm or more, and preferably 3000 nm or less. It is more preferably 2500 nm or less, still more preferably 2200 nm or less, particularly preferably 2000 nm or less, and most preferably 1900 nm or less. When the total thickness of the dielectric multilayer film 3 is equal to or greater than the above lower limit, it is possible to more effectively transmit ultraviolet rays having a wavelength of 220 nm to 225 nm. In addition, transmission of ultraviolet rays having a wavelength of 240 nm to 320 nm can be further suppressed. On the other hand, when the total thickness of the dielectric multilayer film 3 is equal to or less than the above upper limit, it is possible to more effectively transmit ultraviolet rays having a wavelength of 220 nm to 225 nm.
　また、誘電体多層膜３を構成する膜の層数は、好ましくは２０層以上、より好ましくは２５層以上、さらに好ましくは３０層以上、特に好ましくは３５層以上であり、好ましくは１００層以下、より好ましくは８０層以下、さらに好ましくは６０層以下、特に好ましくは４５層以下である。誘電体多層膜３を構成する膜の層数が上記下限値以上である場合、波長２２０ｎｍ～２２５ｎｍにおける紫外線をより一層効果的に透過させることができる。また、波長２４０ｎｍ～３２０ｎｍにおける紫外線の透過をより一層抑制することができる。また、誘電体多層膜３を構成する膜の層数が上記上限値以下である場合、波長２２０ｎｍ～２２５ｎｍにおける紫外線をより一層効果的に透過させることができる。 The number of layers of the films constituting the dielectric multilayer film 3 is preferably 20 layers or more, more preferably 25 layers or more, still more preferably 30 layers or more, particularly preferably 35 layers or more, and preferably 100 layers or less. , more preferably 80 layers or less, still more preferably 60 layers or less, and particularly preferably 45 layers or less. When the number of layers of the films constituting the dielectric multilayer film 3 is equal to or greater than the above lower limit value, it is possible to more effectively transmit ultraviolet rays having a wavelength of 220 nm to 225 nm. In addition, transmission of ultraviolet rays having a wavelength of 240 nm to 320 nm can be further suppressed. Further, when the number of layers of the films constituting the dielectric multilayer film 3 is equal to or less than the above upper limit value, it is possible to more effectively transmit ultraviolet rays having a wavelength of 220 nm to 225 nm.
　なお、上記実施形態では、透明基材２の第１の主面２ａ上に、誘電体多層膜３が設けられている。もっとも、本発明においては、透明基材２の第２の主面２ｂ上にも誘電体多層膜３が設けられていてもよい。すなわち、透明基材２の両側の主面上に誘電体多層膜３が設けられていてもよく、透明基材２の一方側の主面上にのみ誘電体多層膜３が設けられていてもよい。 Note that in the above embodiment, the dielectric multilayer film 3 is provided on the first main surface 2a of the transparent substrate 2. As shown in FIG. However, in the present invention, the dielectric multilayer film 3 may also be provided on the second main surface 2b of the transparent substrate 2. FIG. That is, the dielectric multilayer film 3 may be provided on both main surfaces of the transparent substrate 2, or may be provided only on one main surface of the transparent substrate 2. good.
　また、上記実施形態では、透明基材２の第１の主面２ａ上に、高屈折率膜４から順に高屈折率膜４及び低屈折率膜５が積層されていた。もっとも、本発明においては、透明基材２の第１の主面２ａ上に、低屈折率膜５から順に低屈折率膜５及び高屈折率膜４が積層されていてもよい。 In addition, in the above embodiment, the high refractive index film 4 and the low refractive index film 5 are laminated in order from the high refractive index film 4 on the first main surface 2 a of the transparent substrate 2 . However, in the present invention, the low refractive index film 5 and the high refractive index film 4 may be laminated in order from the low refractive index film 5 on the first main surface 2a of the transparent substrate 2 .
　また、本発明においては、透明基材２の第２の主面２ｂ上に、反射防止膜が設けられていてもよい。この場合、波長２２０ｎｍ～２２５ｎｍにおける紫外線をより一層効果的に透過させることができる。 Further, in the present invention, an antireflection film may be provided on the second main surface 2b of the transparent substrate 2. In this case, ultraviolet rays with a wavelength of 220 nm to 225 nm can be transmitted more effectively.
　反射防止膜としては、特に限定されず、例えば、相対的に屈折率が高い高屈折率膜と相対的に屈折率が低い低屈折率膜とを有する、多層膜を用いることができる。多層膜は、高屈折率膜及び低屈折率膜がこの順に交互に設けられることにより構成されていてもよい。上記高屈折率膜としては、例えば、酸化ハフニウムを主成分とする膜を用いることができる。上記低屈折率膜としては、酸化ケイ素、酸化アルミニウム、酸化ジルコニウム、酸化スズ、又は窒化ケイ素等を主成分とする膜が挙げられる。また、上記多層膜を構成する膜の層数は、例えば、４層以上、１００層以下とすることができる。 The antireflection film is not particularly limited, and for example, a multilayer film having a high refractive index film with a relatively high refractive index and a low refractive index film with a relatively low refractive index can be used. The multilayer film may be configured by alternately providing a high refractive index film and a low refractive index film in this order. As the high refractive index film, for example, a film containing hafnium oxide as a main component can be used. Examples of the low refractive index film include films containing silicon oxide, aluminum oxide, zirconium oxide, tin oxide, silicon nitride, or the like as a main component. Further, the number of layers of films constituting the multilayer film can be, for example, 4 or more and 100 or less.
　なお、本発明の効果を阻害しない限りにおいて、透明基材２の第２の主面２ｂ上には、反射防止膜以外の膜が積層されていてもよい。また、本発明の効果を阻害しない限りにおいて、透明基材２の第１の主面２ａ上に、誘電体多層膜３以外の膜が設けられていてもよい。この場合、透明基材２と、誘電体多層膜３との間に膜が設けられていてもよいし、誘電体多層膜３の上に膜が設けられていてもよい。 A film other than an antireflection film may be laminated on the second main surface 2b of the transparent substrate 2 as long as the effects of the present invention are not impaired. Further, a film other than the dielectric multilayer film 3 may be provided on the first main surface 2a of the transparent substrate 2 as long as the effects of the present invention are not impaired. In this case, a film may be provided between the transparent substrate 2 and the dielectric multilayer film 3 , or a film may be provided on the dielectric multilayer film 3 .
　以下、光学フィルタ１の製造方法の一例について詳細に説明する。 An example of the method for manufacturing the optical filter 1 will be described in detail below.
　（光学フィルタの製造方法）
　膜付き透明基材形成工程；
　まず、透明基材２を用意する。次に、透明基材２の第１の主面２ａ上に誘電体多層膜３を形成する。それによって、膜付き透明基材を形成する。なお、誘電体多層膜３は、透明基材２の第１の主面２ａ上に、高屈折率膜４及び低屈折率膜５をこの順に交互に積層することにより形成することができる。高屈折率膜４及び低屈折率膜５は、それぞれ、スパッタリング法により形成することができる。 (Manufacturing method of optical filter)
film-coated transparent substrate forming step;
First, a transparent substrate 2 is prepared. Next, a dielectric multilayer film 3 is formed on the first main surface 2a of the transparent substrate 2. As shown in FIG. Thereby, a film-coated transparent substrate is formed. The dielectric multilayer film 3 can be formed by alternately laminating the high refractive index film 4 and the low refractive index film 5 on the first main surface 2a of the transparent substrate 2 in this order. The high refractive index film 4 and the low refractive index film 5 can each be formed by a sputtering method.
　高屈折率膜４を成膜するときの基板の温度は、好ましくは３００℃以下、より好ましくは２７０℃以下である。この場合、得られる光学フィルタ１において、波長２４０ｎｍ～３２０ｎｍにおける紫外線の透過をより一層抑制しつつ、波長２２０ｎｍ～２２５ｎｍにおける紫外線をより一層効果的に透過させることができる。なお、高屈折率膜４を成膜するときの基板の温度の下限値は、例えば、２０℃とすることができる。 The temperature of the substrate when forming the high refractive index film 4 is preferably 300° C. or less, more preferably 270° C. or less. In this case, the obtained optical filter 1 can more effectively transmit ultraviolet rays with a wavelength of 220 nm to 225 nm while further suppressing transmission of ultraviolet rays with a wavelength of 240 nm to 320 nm. The lower limit of the temperature of the substrate when forming the high refractive index film 4 can be set to 20° C., for example.
　高屈折率膜４の成膜は、例えば、高屈折率膜４を構成する材料のターゲットを用い、キャリアガスとしてのアルゴンガスなどの不活性ガスの流量を５０ｓｃｃｍ～５００ｓｃｃｍとし、印加電力を０．５ｋＷ～４０ｋＷとして行うことができる。 The high refractive index film 4 is formed by, for example, using a target of the material constituting the high refractive index film 4, setting the flow rate of an inert gas such as argon gas as a carrier gas to 50 sccm to 500 sccm, and applying an electric power of 0.5 sccm. It can be performed as 5 kW to 40 kW.
　低屈折率膜５の成膜は、例えば、低屈折率膜５を構成する材料のターゲットを用い、キャリアガスとしてのアルゴンガスなどの不活性ガスの流量を５０ｓｃｃｍ～５００ｓｃｃｍとし、印加電力を０．５ｋＷ～４０ｋＷとして行うことができる。 The low refractive index film 5 is formed by, for example, using a target of the material constituting the low refractive index film 5, setting the flow rate of an inert gas such as argon gas as a carrier gas to 50 sccm to 500 sccm, and applying an electric power of 0.5 sccm. It can be performed as 5 kW to 40 kW.
　熱処理工程；
　次に、得られた膜付き透明基材を例えば４５０℃以上の温度で加熱処理する。それによって、光学フィルタ１を得ることができる。特に、膜付き透明基材を４５０℃以上の温度で加熱する場合、立方晶系酸化ハフニウム結晶の含有量を相対的により大きくすることができ、上述のＸ線回折測定で得られる上記式（１）における結晶化パラメータＰをより一層大きくすることができる。そのため、得られる光学フィルタ１において、波長２４０ｎｍ～３２０ｎｍにおける紫外線の透過をより一層抑制しつつ、波長２２０ｎｍ～２２５ｎｍにおける紫外線をより一層効果的に透過させることができる。 heat treatment process;
Next, the obtained film-coated transparent substrate is heat-treated at a temperature of 450° C. or higher, for example. Thereby, the optical filter 1 can be obtained. In particular, when the film-coated transparent substrate is heated at a temperature of 450° C. or higher, the content of cubic hafnium oxide crystals can be relatively increased, and the above formula (1 ) can be made much larger. Therefore, in the obtained optical filter 1, it is possible to more effectively transmit ultraviolet rays with a wavelength of 220 nm to 225 nm while further suppressing transmission of ultraviolet rays with a wavelength of 240 nm to 320 nm.
　膜付き透明基材における加熱処理の温度は、好ましくは５００℃以上、より好ましくは５５０℃以上、好ましくは８００℃以下、より好ましくは７５０℃以下である。加熱処理の温度が上記範囲内にある場合、波長２４０ｎｍ～３２０ｎｍにおける紫外線の透過をより一層抑制しつつ、波長２２０ｎｍ～２２５ｎｍにおける紫外線の透過性をより一層高めることができる。 The temperature of the heat treatment for the film-coated transparent substrate is preferably 500°C or higher, more preferably 550°C or higher, preferably 800°C or lower, and more preferably 750°C or lower. When the temperature of the heat treatment is within the above range, it is possible to further suppress the transmission of ultraviolet rays having a wavelength of 240 nm to 320 nm and further increase the transmittance of ultraviolet rays having a wavelength of 220 nm to 225 nm.
　膜付き透明基材における加熱処理の時間は、特に限定されないが、例えば、１０分以上、１２０分以下とすることができる。 The heat treatment time for the film-coated transparent substrate is not particularly limited, but can be, for example, 10 minutes or more and 120 minutes or less.
　なお、本発明においては、加熱処理前の膜付き透明基材のＸ線回折測定において、単斜晶系酸化ハフニウム結晶に由来する（－１　１　１）結晶面による回折ピークの回折強度が小さいことが好ましい。単斜晶系酸化ハフニウム結晶に由来する（－１　１　１）結晶面による回折ピークの強度が、微結晶レベルであることが好ましく、ピーク強度の高さはアモルファスのハローのピーク強度の高さの３倍以内であることがより好ましい。この場合、上述のＸ線回折測定で得られる上記式（１）における結晶化パラメータＰを上記の好適な範囲に調整することができる。そのため、得られる光学フィルタ１において、波長２４０ｎｍ～３２０ｎｍにおける紫外線の透過をより一層抑制しつつ、波長２２０ｎｍ～２２５ｎｍにおける紫外線の透過性をより一層高めることができる。 In the present invention, in the X-ray diffraction measurement of the film-coated transparent substrate before heat treatment, the diffraction intensity of the diffraction peak due to the (−1 1 1) crystal plane derived from the monoclinic hafnium oxide crystal is small. is preferred. The intensity of the diffraction peak due to the (-1 1 1) crystal plane derived from the monoclinic hafnium oxide crystal is preferably at the microcrystal level, and the height of the peak intensity is the height of the peak intensity of the amorphous halo. It is more preferable to be within 3 times. In this case, the crystallization parameter P in the above formula (1) obtained by the above X-ray diffraction measurement can be adjusted to the above preferred range. Therefore, in the obtained optical filter 1, the transmittance of ultraviolet rays with a wavelength of 240 nm to 320 nm can be further suppressed, and the transmittance of ultraviolet rays with a wavelength of 220 nm to 225 nm can be further enhanced.
　本発明において、上述のＸ線回折測定で得られる上記式（１）における結晶化パラメータＰは、例えば、誘電体多層膜３を構成する膜の総数、膜厚、及び材料や、膜付き透明基材の加熱処理温度により、好適な範囲に調整することができる。特に、上述のＸ線回折測定で得られた上記式（１）における結晶化パラメータＰは、膜付き透明基材の加熱処理温度によって、より好適な範囲に調整することができる。この場合、得られる光学フィルタ１において、波長２４０ｎｍ～３２０ｎｍにおける紫外線の透過をより一層抑制しつつ、波長２２０ｎｍ～２２５ｎｍにおける紫外線の透過性をより一層効果的に高めることができる。 In the present invention, the crystallization parameter P in the above formula (1) obtained by the above-described X-ray diffraction measurement is, for example, the total number, film thickness, and material of the films constituting the dielectric multilayer film 3, It can be adjusted to a suitable range depending on the heat treatment temperature of the material. In particular, the crystallization parameter P in the above formula (1) obtained by the above X-ray diffraction measurement can be adjusted to a more suitable range by the heat treatment temperature of the film-coated transparent substrate. In this case, in the obtained optical filter 1, it is possible to more effectively increase the transmittance of ultraviolet rays with a wavelength of 220 nm to 225 nm while further suppressing the transmission of ultraviolet rays with a wavelength of 240 nm to 320 nm.
　［第２の実施形態］
　図２は、本発明の第２の実施形態に係る光学フィルタを示す模式的断面図である。図２に示すように、光学フィルタ２１では、誘電体多層膜２３の最外層２６が、酸化ハフニウムにより構成されている、高屈折率膜４である。その他の点は、第１の実施形態と同様である。 [Second embodiment]
FIG. 2 is a schematic cross-sectional view showing an optical filter according to a second embodiment of the invention. As shown in FIG. 2, in the optical filter 21, the outermost layer 26 of the dielectric multilayer film 23 is the high refractive index film 4 made of hafnium oxide. Other points are the same as in the first embodiment.
　光学フィルタ２１においても、上述のＸ線回折測定で得られる式（１）における結晶化パラメータＰが、０．７以上である。そのため、光学フィルタ２１によっても、波長２４０ｎｍ～３２０ｎｍにおける紫外線の透過を抑制しつつ、波長２２０ｎｍ～２２５ｎｍにおける紫外線を効果的に透過させることができる。 Also in the optical filter 21, the crystallization parameter P in the formula (1) obtained by the above X-ray diffraction measurement is 0.7 or more. Therefore, the optical filter 21 can also effectively transmit ultraviolet rays with a wavelength of 220 nm to 225 nm while suppressing transmission of ultraviolet rays with a wavelength of 240 nm to 320 nm.
　ところで、波長２２０ｎｍ～２２５ｎｍの範囲の紫外線を発光するエキシマランプ等を用いた場合、照射される光により装置部材が劣化し、酸性のガスが発生する場合がある。このガスにより光学フィルタの膜が浸食され、それによって光学特性が変化し、要求特性を満たせない場合がある。 By the way, when an excimer lamp or the like that emits ultraviolet light with a wavelength of 220 nm to 225 nm is used, the irradiated light may deteriorate the device members and generate acidic gas. The gas corrodes the film of the optical filter, which changes the optical characteristics and may not satisfy the required characteristics.
　これに対して、光学フィルタ２１のように、最外層２６が酸化ハフニウムにより構成されている場合、酸性のガスによる浸食をより一層抑制することができ、光学特性の変化をより一層抑制することができる。 On the other hand, like the optical filter 21, when the outermost layer 26 is made of hafnium oxide, it is possible to further suppress the erosion due to the acidic gas, thereby further suppressing the change in the optical characteristics. can.
　また、最外層２６の厚みは、好ましくは１ｎｍ以上、より好ましくは２ｎｍ以上、好ましくは１０ｎｍ以下、より好ましくは７ｎｍ以下である。最外層２６の厚みが上記下限値以上である場合、酸性のガスによる浸食をより一層抑制することができ、光学特性の変化をより一層抑制することができる。一方、最外層２６の厚みが上記上限値以下である場合、波長２４０ｎｍ～３２０ｎｍにおける紫外線の透過をより一層抑制しつつ、波長２２０ｎｍ～２２５ｎｍにおける紫外線をより一層効果的に透過させることができる。 Further, the thickness of the outermost layer 26 is preferably 1 nm or more, more preferably 2 nm or more, preferably 10 nm or less, more preferably 7 nm or less. When the thickness of the outermost layer 26 is equal to or greater than the above lower limit, erosion due to acidic gases can be further suppressed, and changes in optical properties can be further suppressed. On the other hand, when the thickness of the outermost layer 26 is equal to or less than the above upper limit, it is possible to further suppress the transmission of ultraviolet rays with a wavelength of 240 nm to 320 nm, and to transmit the ultraviolet rays with a wavelength of 220 nm to 225 nm more effectively.
　［殺菌装置］
　図３は、本発明の一実施形態に係る殺菌装置を示す模式図である。図３に示すように、殺菌装置３１は、筐体３２と、光源３３と、光学フィルタ１とを備える。筐体３２の内部には、放出光の波長が、波長１９０ｎｍ～２３０ｎｍの波長域に存在する、光源３３が配置されている。光源３３及び光学フィルタ１は、対向するように設けられている。このとき、誘電体多層膜３は、光源３３側に設けられていることが好ましい。殺菌装置３１では、光源３３から発せられた放出光が、光学フィルタ１を介して、殺菌対象物３４に照射される。 [Sterilizer]
FIG. 3 is a schematic diagram showing a sterilization device according to one embodiment of the present invention. As shown in FIG. 3 , the sterilization device 31 includes a housing 32 , a light source 33 and an optical filter 1 . Inside the housing 32, a light source 33 is arranged which emits light in a wavelength range of 190 nm to 230 nm. The light source 33 and the optical filter 1 are provided so as to face each other. At this time, the dielectric multilayer film 3 is preferably provided on the light source 33 side. In the sterilization device 31 , an object 34 to be sterilized is irradiated with emitted light emitted from the light source 33 through the optical filter 1 .
　光源３３としては、例えば、エキシマランプを用いることができる。エキシマランプとしては、波長２２０ｎｍ～２２５ｎｍの範囲の紫外線を発光するエキシマランプを用いることが好ましい。このようなエキシマランプとしては、例えば、ＫｒＣｌエキシマランプを用いることができる。エキシマランプは、ＫｒＢｒエキシマランプであってもよい。 For example, an excimer lamp can be used as the light source 33 . As the excimer lamp, it is preferable to use an excimer lamp that emits ultraviolet light having a wavelength of 220 nm to 225 nm. As such an excimer lamp, for example, a KrCl excimer lamp can be used. The excimer lamp may be a KrBr excimer lamp.
　本実施形態の殺菌装置３１では、上述した光学フィルタ１を用いているので、殺菌処理に有用な紫外線を効率よく透過させることができる。そのため、殺菌対象物３４に効率良く紫外線殺菌を施すことができる。なお、紫外線殺菌では、細菌などの殺菌対象生物の細胞内におけるＤＮＡに紫外線を作用させて選択的に不活化させることができる。また、紫外線殺菌では、ウイルスに紫外線を作用させて選択的に不活化させることもできる。なかでも、殺菌装置３１は、処理対象微生物を不活化処理するために用いられることがより好ましい。 Since the sterilization device 31 of this embodiment uses the optical filter 1 described above, it is possible to efficiently transmit ultraviolet rays useful for sterilization. Therefore, the object 34 to be sterilized can be efficiently sterilized with ultraviolet light. In addition, in the ultraviolet sterilization, the DNA in the cells of organisms to be sterilized such as bacteria can be selectively inactivated by the action of ultraviolet light. Also, in ultraviolet sterilization, viruses can be selectively inactivated by the action of ultraviolet rays. Above all, the sterilizer 31 is more preferably used for inactivating microorganisms to be treated.
　以下、本発明について、具体的な実施例に基づいて、さらに詳細に説明する。本発明は、以下の実施例に何ら限定されるものではなく、その要旨を変更しない範囲において適宜変更して実施することが可能である。 Hereinafter, the present invention will be described in more detail based on specific examples. The present invention is by no means limited to the following examples, and can be modified as appropriate without changing the gist of the invention.
　（製造例１）
　まず、透明基材として合成石英ガラス基板（ＵＳＴＲＯＮ社製）を用意した。次に、用意した透明基材の一方側主面上に、スパッタリングにより誘電体多層膜を成膜した。具体的には、まず、キャリアガスとしてアルゴンガスと酸素ガスとを用い、ハフニウムのターゲットをスパッタリングし、透明基材の一方側主面上に酸化ハフニウム膜（ＨｆＯ２膜）を成膜した。なお、この際、アルゴンガス及び酸素ガスの流量をそれぞれ１００ｓｃｃｍとし、ターゲット印加電力（成膜電力）を４ｋＷとした。次に、キャリアガスとしてアルゴンガスと酸素ガスを用い、シリコンのターゲットをスパッタリングし、ＨｆＯ２膜の上に酸化ケイ素膜（ＳｉＯ２膜）を成膜した。なお、この際、アルゴンガス及び酸素ガスの流量を１００ｓｃｃｍとし、ターゲット印加電力（成膜電力）を４ｋＷとした。この操作を繰り返すことにより、透明基材の一方側主面上に、ＨｆＯ２膜とＳｉＯ２膜とが、１層ずつ交互に積層された、合計３８層の膜を有する誘電体多層膜を形成し、膜付き透明基材を得た。なお、成膜の間、基板温度は、室温（２０℃）とした。 (Production example 1)
First, a synthetic quartz glass substrate (manufactured by USTRON) was prepared as a transparent substrate. Next, a dielectric multilayer film was formed by sputtering on one main surface of the prepared transparent substrate. Specifically, first, using argon gas and oxygen gas as carrier gases, a hafnium target was sputtered to form a hafnium oxide film (HfO 2 film) on one main surface of the transparent substrate. At this time, the flow rates of argon gas and oxygen gas were each set to 100 sccm, and the power applied to the target (film formation power) was set to 4 kW. Next, using argon gas and oxygen gas as carrier gases, a silicon target was sputtered to form a silicon oxide film (SiO 2 film) on the HfO 2 film. At this time, the flow rates of argon gas and oxygen gas were set to 100 sccm, and the power applied to the target (film formation power) was set to 4 kW. By repeating this operation, a dielectric multilayer film having a total of 38 layers, in which HfO 2 films and SiO 2 films are alternately laminated one by one, is formed on one main surface of the transparent substrate. to obtain a film-coated transparent substrate. The substrate temperature was set at room temperature (20° C.) during film formation.
　（製造例２）
　成膜の間、基板温度を２７０℃としたこと以外は、製造例１と同様にして膜付き透明基材を得た。 (Production example 2)
A film-coated transparent substrate was obtained in the same manner as in Production Example 1, except that the substrate temperature was set to 270° C. during film formation.
　（製造例３）
　透明基材として溶融石英ガラス基板（ＵＳＴＲＯＮ社製）を用いたこと及び各層の膜厚を下記の表１に示すように成膜したこと以外は、製造例１と同様にして膜付き透明基材を得た。 (Production example 3)
A transparent substrate with a film was prepared in the same manner as in Production Example 1, except that a fused quartz glass substrate (manufactured by USTRON) was used as the transparent substrate and the thickness of each layer was formed as shown in Table 1 below. got
　（製造例４）
　透明基材としてホウケイ酸ガラス基板（日本電気硝子社製、品番「ＢＵ－４１」）を用いたこと及び各層の膜厚を下記の表１に示すように成膜したこと以外は、製造例１と同様にして膜付き透明基材を得た。 (Production example 4)
Production Example 1, except that a borosilicate glass substrate (manufactured by Nippon Electric Glass Co., Ltd., product number "BU-41") was used as the transparent base material and the film thickness of each layer was formed as shown in Table 1 below. A film-coated transparent substrate was obtained in the same manner as above.
　製造例１～４で作製した膜付き透明基材における各層の厚みは、下記の表１に示す通りである。 The thickness of each layer in the film-coated transparent substrates produced in Production Examples 1 to 4 is as shown in Table 1 below.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　（製造例５）
　透明基材として溶融石英ガラス基板（ＵＳＴＲＯＮ社製）を用いたこと及び各層の膜厚を上記の表１に示すように成膜したこと以外は、製造例１と同様にして膜付き透明基材を得た。 (Production example 5)
A transparent substrate with a film was prepared in the same manner as in Production Example 1, except that a fused quartz glass substrate (manufactured by USTRON) was used as the transparent substrate and the film thickness of each layer was formed as shown in Table 1 above. got
　（実施例１～１６及び比較例１～４）
　実施例１では、製造例１で得られた膜付き透明基材を、大気雰囲気下、５００℃の温度で６０分間加熱処理することにより、光学フィルタを得た。実施例２～１６においても同様に、各製造例で得られた膜付き透明基材を、大気雰囲気下で、下記の表２に示す温度及び時間で加熱処理することにより、光学フィルタを得た。また、下記の表２に示すように、比較例１～４では、各製造例で得られた膜付き透明基材の加熱処理を行わずに、そのまま光学フィルタとして用いた。 (Examples 1 to 16 and Comparative Examples 1 to 4)
In Example 1, an optical filter was obtained by heat-treating the film-coated transparent substrate obtained in Production Example 1 at a temperature of 500° C. for 60 minutes in an air atmosphere. Similarly, in Examples 2 to 16, optical filters were obtained by heat-treating the film-coated transparent substrates obtained in each production example in an air atmosphere at the temperatures and times shown in Table 2 below. . Further, as shown in Table 2 below, in Comparative Examples 1 to 4, the film-coated transparent substrates obtained in each production example were used as they were as optical filters without being subjected to heat treatment.
　［評価］
　（Ｘ線回折測定）
　実施例１～１６及び比較例１～４の光学フィルタについて、広角Ｘ線回折法によりＸ線回折測定を行った。Ｘ線回折装置としては、リガク社製、品番「ＳｍａｒｔＬａｂ」を用いた。線源としてはＣｕＫα線（波長１．５４１８Å）を用い、スキャン軸：２θ／ω、測定範囲：１０°～６５°、走査速度：２°／分、管電流：２００ｍＡ、管電圧：４５ｋＶの条件で測定を行った。得られた光学フィルタにおけるＸ線回折スペクトルの一例を図４に示す。 [evaluation]
(X-ray diffraction measurement)
The optical filters of Examples 1 to 16 and Comparative Examples 1 to 4 were subjected to X-ray diffraction measurement by a wide-angle X-ray diffraction method. As an X-ray diffractometer, Rigaku's product number "SmartLab" was used. Using CuKα rays (wavelength 1.5418 Å) as a radiation source, scan axis: 2θ/ω, measurement range: 10° to 65°, scanning speed: 2°/min, tube current: 200 mA, tube voltage: 45 kV. was measured. An example of the X-ray diffraction spectrum of the obtained optical filter is shown in FIG.
　図４は、実施例２及び比較例１で得られた光学フィルタのＸ線回折スペクトルを示す図である。図４に示すように、実施例２のＸ線回折スペクトルでは、２θ＝３０．７°付近に立方晶系酸化ハフニウム結晶に由来する（１　１　１）結晶面による回折ピークが観察され、２θ＝２８．４°付近に単斜晶系酸化ハフニウム結晶に由来する（－１　１　１）結晶面による回折ピークが観察された。一方、比較例１では、立方晶系酸化ハフニウム結晶に由来する（１　１　１）結晶面による回折ピークが観察されず、２θ＝２８°付近に単斜晶系酸化ハフニウム結晶に由来する（－１　１　１）結晶面による微小な回折ピークと、２θ＝２８°～３２°付近に非晶質酸化ハフニウムに由来するフロードなハローパターンのみが観察された。 4 is a diagram showing the X-ray diffraction spectra of the optical filters obtained in Example 2 and Comparative Example 1. FIG. As shown in FIG. 4, in the X-ray diffraction spectrum of Example 2, a diffraction peak due to the (1 1 1) crystal face derived from the cubic hafnium oxide crystal is observed near 2θ=30.7°. A diffraction peak due to the (-1 1 1) crystal face derived from the monoclinic hafnium oxide crystal was observed at around 28.4°. On the other hand, in Comparative Example 1, no diffraction peak due to the (1 1 1) crystal plane derived from the cubic hafnium oxide crystal was observed, and the diffraction peak derived from the monoclinic hafnium oxide crystal (-1 1 1) Only minute diffraction peaks due to crystal planes and floating halo patterns derived from amorphous hafnium oxide were observed near 2θ=28° to 32°.
　同様にして、実施例１，３～１６及び比較例２～４の光学フィルタについても、Ｘ線回折測定を行い、以下のようにして、立方晶系酸化ハフニウム結晶に由来する（１　１　１）結晶面による回折ピークの回折強度Ｉｃと、単斜晶系酸化ハフニウム結晶に由来する（－１　１　１）結晶面による回折ピークの回折強度Ｉｍと、非晶質酸化ハフニウムに由来する回折ピークの回折強度Ｉａとを求めた。 Similarly, the optical filters of Examples 1, 3 to 16 and Comparative Examples 2 to 4 were also subjected to X-ray diffraction measurement. The diffraction intensity I c of the diffraction peak due to the crystal plane, the diffraction intensity I m of the diffraction peak due to the (−1 1 1) crystal plane derived from the monoclinic hafnium oxide crystal, and the diffraction peak derived from the amorphous hafnium oxide The diffraction intensity Ia of was obtained.
　上記のようにして測定した光学フィルタのＸ線回折プロファイルにおいて、２θ＝１０°及び２θ＝４０°の端点を結ぶ直線をバックグラウンドとして除去した。次に、バックグラウンドを除去したＸ線回折プロファイルにおいて、初期条件として、２θ＝２８°付近に単斜晶系酸化ハフニウム結晶に由来する（－１　１　１）結晶面によるフィッティング用ピークを設定し、２θ＝３０°付近に立方晶系酸化ハフニウム結晶に由来する（１　１　１）結晶面によるフィッティング用ピークを設定し、２θ＝２８°～３２°の範囲に非晶質酸化ハフニウムに由来するフィッティング用ピークを設定し、２θ＝２０°～２５°の範囲に透明基材に由来するフィッティング用ピークを設定した。 In the X-ray diffraction profile of the optical filter measured as described above, a straight line connecting the end points of 2θ=10° and 2θ=40° was removed as the background. Next, in the X-ray diffraction profile from which the background has been removed, as an initial condition, a peak for fitting due to the (-1 1 1) crystal face derived from the monoclinic hafnium oxide crystal is set near 2θ = 28 °, A fitting peak derived from the (1 1 1) crystal face derived from the cubic hafnium oxide crystal is set near 2θ = 30°, and a fitting peak derived from amorphous hafnium oxide is set in the range of 2θ = 28° to 32°. A peak was set, and a fitting peak derived from the transparent substrate was set in the range of 2θ=20° to 25°.
　なお、フィッティング関数としては、擬フォークト関数（ｐｓｅｕｄｏ－Ｖｏｉｇｔ　ｆｕｎｃｔｉｏｎ）を使用した。また、非線形最小二乗法により、実測のＸ線回折プロファイルと各フィッティング用ピークの合成プロファイルの間の残差二乗和が最小となるように、各フィッティング用ピークの回折角（２θ）、半値全幅（ＦＷＨＭ）、積分強度（Ｉ）、ローレンツ関数（Ｌｏｒｅｎｔｚｉａｎ　ｆｕｎｃｔｉｏｎ）とガウス関数（Ｇａｕｓｓｉａｎ　ｆｕｎｃｔｉｏｎ）の混合比を最適化した。そして、最適なフィッティング結果が得られた際の単斜晶系酸化ハフニウム結晶（単斜晶系ＨｆＯ２）に由来する（－１　１　１）結晶面による回折ピークの積分強度を回折強度Ｉｍとし、立方晶系酸化ハフニウム結晶（立方晶系ＨｆＯ２）に由来する（１　１　１）結晶面による回折ピークの積分強度を回折強度Ｉｃとし、非晶質酸化ハフニウム（非晶質ＨｆＯ２）に由来する回折ピークの積分強度を回折強度Ｉａとした。なお、ピークフィッティングは、リガク社製、品番「ＰＤＸＬ」を用いて行った。 A pseudo-Voigt function was used as the fitting function. In addition, by the nonlinear least-squares method, the diffraction angle (2θ) and the full width at half maximum ( FWHM), integrated intensity (I), and the mixture ratio of Lorentzian and Gaussian functions were optimized. Then, the integrated intensity of the diffraction peak due to the (−1 1 1) crystal plane derived from the monoclinic hafnium oxide crystal (monoclinic HfO 2 ) when the optimum fitting result is obtained is defined as the diffraction intensity Im . , The integrated intensity of the diffraction peak due to the (1 1 1) crystal plane derived from the cubic hafnium oxide crystal (cubic HfO 2 ) is defined as the diffraction intensity Ic , and the amorphous hafnium oxide (amorphous HfO 2 ) The integrated intensity of the derived diffraction peak was defined as the diffraction intensity Ia . The peak fitting was performed using Rigaku's product number "PDXL".
　得られた回折強度Ｉｃ、回折強度Ｉｍと、及び回折強度Ｉａを用いて、下記式（１）における結晶化パラメータＰを求めた。 Using the obtained diffraction intensity I c , diffraction intensity I m and diffraction intensity I a , the crystallization parameter P in the following formula (1) was obtained.
　Ｐ＝（２×Ｉｃ＋Ｉｍ）／（Ｉｃ＋Ｉｍ＋Ｉａ）…式（１） P=(2× Ic + Im )/( Ic + Im + Ia ) Equation (1)
　結果を下記の表２に示す。なお、下記の表２においては、立方晶系ＨｆＯ２、単斜晶系ＨｆＯ２、及び非晶質ＨｆＯ２の回折ピーク位置を併せて示している。 The results are shown in Table 2 below. Table 2 below also shows the diffraction peak positions of cubic HfO 2 , monoclinic HfO 2 , and amorphous HfO 2 .
　（分光透過率）
　実施例１～１６及び比較例１～４の光学フィルタについて、分光光度計（日立ハイテクサイエンス社製、品番「ＵＨ４１５０」）を用いて、分光透過率を測定した。具体的には、入射角度（入射角）を０°とし、測定波長を１９０ｎｍ～４００ｎｍとした。得られた光学フィルタにおける透過スペクトルの一例を図５に示した。 (spectral transmittance)
The spectral transmittance of the optical filters of Examples 1 to 16 and Comparative Examples 1 to 4 was measured using a spectrophotometer (manufactured by Hitachi High-Tech Science, product number "UH4150"). Specifically, the incident angle (incidence angle) was set to 0°, and the measurement wavelength was set to 190 nm to 400 nm. An example of the transmission spectrum of the obtained optical filter is shown in FIG.
　図５は、実施例２及び比較例１で得られた光学フィルタの透過スペクトルを示す図である。図５に示すように、実施例２では、波長２２０ｎｍ～２２５ｎｍにおける分光透過率の最小値が高められていることを確認することができる。他方、比較例１では、波長２２０ｎｍ～２２５ｎｍにおける分光透過率の最小値を十分に高めることができなかった。また、実施例２及び比較例１では、いずれも波長２４０ｎｍ～３２０ｎｍにおける分光透過率の最大値が低められていることがわかる。 5 is a diagram showing transmission spectra of the optical filters obtained in Example 2 and Comparative Example 1. FIG. As shown in FIG. 5, in Example 2, it can be confirmed that the minimum value of the spectral transmittance at wavelengths of 220 nm to 225 nm is increased. On the other hand, in Comparative Example 1, the minimum spectral transmittance at wavelengths of 220 nm to 225 nm could not be sufficiently increased. Moreover, in both Example 2 and Comparative Example 1, the maximum value of the spectral transmittance at wavelengths of 240 nm to 320 nm is lowered.
　同様にして、実施例１，３～１６及び比較例２～４の光学フィルタについても、分光透過率を測定した。なお、上述のように入射角は０°とした。 Similarly, the spectral transmittance of the optical filters of Examples 1, 3 to 16 and Comparative Examples 2 to 4 was measured. Note that the incident angle was set to 0° as described above.
　結果を下記の表２及び図６に示す。なお、図６は、実施例１～１６及び比較例１～４における結晶化パラメータＰと、波長２２０ｎｍ～２２５ｎｍにおける分光透過率の最小値との関係を示すグラフである。 The results are shown in Table 2 and Figure 6 below. FIG. 6 is a graph showing the relationship between the crystallization parameter P in Examples 1 to 16 and Comparative Examples 1 to 4 and the minimum value of spectral transmittance at wavelengths of 220 nm to 225 nm.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２及び図６から明らかなように、結晶化パラメータＰが０．７以上である実施例１～１６の光学フィルタでは、波長２２０ｎｍ～２２５ｎｍの紫外線を効果的に透過させることができていることがわかる（波長２２０ｎｍ～２２５ｎｍにおける分光透過率の最小値が５０％以上）。また、表２から明らかなように、実施例１～１６の光学フィルタでは、波長２４０ｎｍ～３２０ｎｍにおける紫外線の透過を抑制できていることがわかる。他方、結晶化パラメータＰが０．７未満である比較例１～４の光学フィルタでは、波長２２０ｎｍ～２２５ｎｍの紫外線を十分に透過させることができていないことがわかる（波長２２０ｎｍ～２２５ｎｍにおける分光透過率の最小値が５０％未満）。 As is clear from Table 2 and FIG. 6, the optical filters of Examples 1 to 16, in which the crystallization parameter P is 0.7 or more, can effectively transmit ultraviolet rays having a wavelength of 220 nm to 225 nm. (minimum value of spectral transmittance at wavelength 220 nm to 225 nm is 50% or more). Moreover, as is clear from Table 2, the optical filters of Examples 1 to 16 can suppress the transmission of ultraviolet rays having a wavelength of 240 nm to 320 nm. On the other hand, it can be seen that the optical filters of Comparative Examples 1 to 4, in which the crystallization parameter P is less than 0.7, cannot sufficiently transmit ultraviolet rays with wavelengths of 220 nm to 225 nm (spectral transmission at wavelengths of 220 nm to 225 nm). % minimum less than 50%).
１，２１…光学フィルタ
１ａ…主面
２…透明基材
２ａ…第１の主面
２ｂ…第２の主面
３，２３…誘電体多層膜
４…高屈折率膜
５…低屈折率膜
２６…最外層
３１…殺菌装置
３２…筐体
３３…光源
３４…殺菌対象物 Reference Signs List 1, 21 Optical filter 1a Main surface 2 Transparent substrate 2a First main surface 2b Second main surface 3, 23 Dielectric multilayer film 4 High refractive index film 5 Low refractive index film 26 ... outermost layer 31 ... sterilization device 32 ... housing 33 ... light source 34 ... object to be sterilized

Claims (6)

  1. 　透明基材と、
    　前記透明基材上に設けられており、酸化ハフニウムを含む、誘電体多層膜と、
    を備え、
    　Ｘ線回折測定において、立方晶系酸化ハフニウム結晶に由来する（１　１　１）結晶面による回折ピークの回折強度をＩｃとし、単斜晶系酸化ハフニウム結晶に由来する（－１　１　１）結晶面による回折ピークの回折強度をＩｍとし、非晶質酸化ハフニウムに由来する回折ピークの回折強度をＩａとしたときに、下記式（１）における結晶化パラメータＰが、０．７以上である、光学フィルタ。
    　Ｐ＝（２×Ｉｃ＋Ｉｍ）／（Ｉｃ＋Ｉｍ＋Ｉａ）…式（１）     a transparent substrate;
    a dielectric multilayer film provided on the transparent substrate and containing hafnium oxide;
    with
    In the X-ray diffraction measurement, the diffraction intensity of the diffraction peak due to the (1 1 1) crystal plane derived from the cubic hafnium oxide crystal is defined as Ic , and the (-1 1 1) crystal derived from the monoclinic hafnium oxide crystal. When the diffraction intensity of the diffraction peak due to the plane is Im and the diffraction intensity of the diffraction peak derived from amorphous hafnium oxide is Ia , the crystallization parameter P in the following formula (1) is 0.7 or more. There is an optical filter.
    P=(2× Ic + Im )/( Ic + Im + Ia ) Equation (1)
  2. 　透明基材と、
    　前記透明基材上に設けられており、酸化ハフニウムを含む、誘電体多層膜と、
    を備え、
    　ＣｕＫα線を用いたＸ線回折測定において、回折角２θ＝３０．３°±０．７゜の範囲内に存在する結晶回折ピークの回折強度をＩｃとし、回折角２θ＝２８．４°±０．５゜の範囲内に存在する結晶回折ピークの回折強度をＩｍとし、回折角２θ＝３０．０°±２．０゜の範囲内に存在する非晶質回折ピークの回折強度をＩａとしたときに、下記式（１）における結晶化パラメータＰが、０．７以上である、光学フィルタ。
    　Ｐ＝（２×Ｉｃ＋Ｉｍ）／（Ｉｃ＋Ｉｍ＋Ｉａ）…式（１）     a transparent substrate;
    a dielectric multilayer film provided on the transparent substrate and containing hafnium oxide;
    with
    In the X-ray diffraction measurement using CuKα rays, the diffraction intensity of the crystal diffraction peak existing within the range of the diffraction angle 2θ = 30.3° ± 0.7° is Ic , and the diffraction angle 2θ = 28.4° ± Let Im be the diffraction intensity of the crystalline diffraction peak existing within the range of 0.5°, and Ia be the diffraction intensity of the amorphous diffraction peak existing within the range of the diffraction angle 2θ = 30.0° ± 2.0°. An optical filter, wherein the crystallization parameter P in the following formula (1) is 0.7 or more.
    P=(2× Ic + Im )/( Ic + Im + Ia ) Equation (1)
  3. 　前記誘電体多層膜が、相対的に屈折率が高い高屈折率膜と、相対的に屈折率が低い低屈折率膜とを有し、
    　前記高屈折率膜が、前記酸化ハフニウムを含む膜である、請求項１又は２に記載の光学フィルタ。     The dielectric multilayer film has a high refractive index film with a relatively high refractive index and a low refractive index film with a relatively low refractive index,
    3. The optical filter according to claim 1, wherein said high refractive index film is a film containing said hafnium oxide.
  4. 　前記低屈折率膜が、酸化ケイ素を含む膜である、請求項３に記載の光学フィルタ。 The optical filter according to claim 3, wherein the low refractive index film is a film containing silicon oxide.
  5. 　入射角０°において、波長２２０ｎｍ～２２５ｎｍにおける分光透過率の最小値が、５０％以上であり、
    　入射角０°において、波長２４０ｎｍ～３２０ｎｍにおける分光透過率の最大値が、５％以下である、請求項１又は２に記載の光学フィルタ。     At an incident angle of 0°, the minimum spectral transmittance at a wavelength of 220 nm to 225 nm is 50% or more,
    3. The optical filter according to claim 1, wherein the maximum value of spectral transmittance at a wavelength of 240 nm to 320 nm is 5% or less at an incident angle of 0°.
  6. 　処理対象微生物を不活化処理するための殺菌装置であって、
    　放出光の波長が、波長１９０ｎｍ～２３０ｎｍの波長域に存在する、光源と、
    　請求項１又は２に記載の光学フィルタと、
    を備える、殺菌装置。     A sterilization device for inactivating microorganisms to be treated,
    a light source whose emitted light has a wavelength in the wavelength range of 190 nm to 230 nm;
    An optical filter according to claim 1 or 2;
    A sterilizer, comprising:
PCT/JP2022/045959 2021-12-17 2022-12-14 Optical filter and sterilization device WO2023112940A1 (en)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013068885A (en) * 2011-09-26 2013-04-18 Nidek Co Ltd Bandpass filter, and method of manufacturing bandpass filter
JP2019115525A (en) * 2017-12-27 2019-07-18 ウシオ電機株式会社 Inactivation processing device of microorganism and cell activation processing device, as well as inactivation processing method of microorganism and cell activation processing method

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013068885A (en) * 2011-09-26 2013-04-18 Nidek Co Ltd Bandpass filter, and method of manufacturing bandpass filter
JP2019115525A (en) * 2017-12-27 2019-07-18 ウシオ電機株式会社 Inactivation processing device of microorganism and cell activation processing device, as well as inactivation processing method of microorganism and cell activation processing method

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