JPWO2018100991A1 - UV transmission filter - Google Patents

Abstract

Provided is an ultraviolet transmission filter that has a high transmittance of ultraviolet rays, particularly deep ultraviolet light, and that suppresses deterioration of transmittance even when used for a long period of time. The glass plate 2 has a protective film 3 provided on the main surface of the glass plate 2, and the glass plate 2 is expressed in terms of oxide-based mole percentage, and SiO 2 is 55 to 80% and B 2 O 3 is 12 to 27. %, R2O (R represents at least one alkali metal selected from the group consisting of Li, Na, and K) 4-20%, Al2O3 0-5%, R'O (R 'is Represents at least one alkaline earth metal selected from the group consisting of Mg, Ca, Sr, and Ba.) 0-5%, ZnO 0-5%, ZrO2 0-20%, Ta2O5 The ultraviolet transmissive filter 1 containing 0 to 5%, and the glass plate 2 is formed of glass having a transmittance of 70% or more at a wavelength of 254 nm in a spectral transmittance at a thickness of 0.5 mm.

Description

  The present invention relates to an ultraviolet transmission filter having a high transmittance for light having a wavelength in the ultraviolet region.

  Conventionally known are low-pressure mercury lamps and high-pressure mercury lamps as ultraviolet light sources. In recent years, small-sized and low-cost ultraviolet LEDs (ultraviolet light-emitting diodes) have become widespread, and the use of various applications such as water sterilizers, ultraviolet curable resin curing devices, and ultraviolet sensors has increased.

  Conventionally, there is quartz glass that efficiently transmits ultraviolet rays as a glass used in an apparatus including such an ultraviolet light source. However, quartz glass has a problem of high manufacturing costs. On the other hand, phosphate glass and borosilicate glass are known as glasses that efficiently transmit ultraviolet rays other than quartz glass (see, for example, Patent Documents 1 and 2).

  However, these glasses have low transmittance of light having a wavelength of 400 nm or less, particularly light having a wavelength of 200 to 280 nm (hereinafter sometimes referred to as deep ultraviolet light), and improvement has been desired.

  Further, for example, the water sterilizer, the ultraviolet curable resin curing device, the ultraviolet sensor, etc. may be used for a long period of time or placed in a high temperature and high humidity environment. Therefore, it is preferable that the ultraviolet transmittance of the glass is suppressed from being deteriorated even under long-term use or in a high-temperature and high-humidity environment.

JP-A-62-027346 JP 60-046946 A

  An object of the present invention is to provide an ultraviolet transmission filter that has high transmittance of ultraviolet rays, particularly deep ultraviolet light, and that suppresses deterioration of transmittance even when used for a long period of time.

The ultraviolet transmissive filter of the present invention has a glass plate and a protective film provided on the main surface of the glass plate, and the glass plate is an oxide-based mole percentage display, and SiO ₂ is 55-80. %, B ₂ O ₃ 12 to 27%, R ₂ O (R represents at least one alkali metal selected from the group consisting of Li, Na and K) 4 to 20%, Al ₂ 0 to 5% of O ₃ , 0 to 5% of R′O (R ′ represents at least one alkaline earth metal selected from the group consisting of Mg, Ca, Sr, and Ba), ZnO 0 to 5%, ZrO ₂ 0 to 20%, Ta ₂ O ₅ 0 to 5%, and the glass plate has a transmittance at a wavelength of 254 nm in a spectral transmittance at a thickness of 0.5 mm. It is formed of glass that is 70% or more.

  In the ultraviolet transmission filter of the present invention, it is preferable that the protective film imparts at least one function selected from weather resistance, alkali resistance, acid resistance, and chemical resistance to the ultraviolet transmission filter.

In the ultraviolet transmission filter of the present invention, the protective film is a film containing SiO ₂ as a main component, and the protective film preferably contains hollow silica particles.

In the ultraviolet transmission filter of the present invention, the protective film is selected from the group consisting of SiO ₂ , Si ₃ N ₄ , Si ₄ O ₅ N ₃ , Al ₂ O ₃ , ZrO ₂ , TiO ₂ , Ta ₂ O ₅ and MgF _2. It is preferable to consist of at least one selected monolayer film.

  In the ultraviolet transmissive filter of the present invention, the protective film is preferably made of a dielectric multilayer film.

  In the ultraviolet transmission filter of the present invention, the dielectric multilayer film is formed by alternately laminating low refractive index films and high refractive index films, and the high refractive index film is at least one selected from hafnium oxide and tantalum oxide. It is preferable to contain.

  In the ultraviolet transmission filter of the present invention, the average transmittance at a wavelength of 200 nm to 230 nm is preferably 60% or less.

In the ultraviolet transmission filter of the present invention, it is preferable that the glass does not substantially contain Al ₂ O ₃ .

In the ultraviolet transmission filter of the present invention, it is preferable that the glass contains Al ₂ O ₃ in an amount of 0.5 to 5%.

In the ultraviolet transmission filter of the present invention, the glass preferably contains 1.5 to 20% of ZrO ₂ .

In the ultraviolet transmissive filter of the present invention, the glass preferably contains 0.01 to ₂ % of Ta ₂ O ₅ .

  In the ultraviolet transmission filter of the present invention, the glass does not substantially contain R′O (R ′ represents an alkaline earth metal selected from the group consisting of Mg, Ca, Sr, and Ba). Is preferred.

In the ultraviolet transmission filter of the present invention, the glass preferably further contains 0.00005 to 0.01% of Fe ₂ O ₃ and / or 0.0001 to 0.02% of TiO ₂ .

In the ultraviolet transmission filter of the present invention, the glass may contain substantially no Cr ₂ O ₃ , NiO, CuO, CeO ₂ , V ₂ O ₅ , WO ₃ , MoO ₃ , MnO ₂ , and CoO. preferable.

  In the ultraviolet transmission filter of the present invention, it is preferable that the glass does not substantially contain Cl.

In the ultraviolet transmission filter of the present invention, it is preferable that the degree of deterioration of transmittance at a wavelength of 254 nm, which is obtained by the following formula in the weather resistance test, is 3% or less.
Degree of deterioration by weather resistance test (%) = [(T0−T2) / T0] × 100
(In the formula, T0 is an initial transmittance at a wavelength of 254 nm of an ultraviolet transmission filter having a protective film on one main surface of the glass plate having a thickness of 0.5 mm whose both surfaces are optically polished, and T2 is the ultraviolet ray. (The transmittance at a wavelength of 254 nm after holding the transmission filter in an atmosphere of 85 ° C. and 85% relative humidity for 500 hours.)

In the ultraviolet transmission filter of the present invention, it is preferable that the deterioration degree of the transmittance at a wavelength of 254 nm, which is obtained by the following formula in the weather resistance test, is 5% or less.
Degree of deterioration by weather resistance test (%) = [(T0−T1) / T0] × 100
(In the formula, T0 is an initial transmittance at a wavelength of 254 nm of an ultraviolet transmission filter having a protective film on one main surface of the glass plate having a thickness of 0.5 mm whose both surfaces are optically polished, and T1 is the ultraviolet ray. (The transmittance at a wavelength of 254 nm after holding the transmission filter in an atmosphere of 85 ° C. and 85% relative humidity for 1000 hours.)

In the ultraviolet transmission filter of the present invention, the degree of transmittance deterioration at a wavelength of 254 nm, which is obtained by the following formula in the ultraviolet irradiation test, is preferably 5% or less.
Degree of deterioration by ultraviolet irradiation test (%) = [(T0−T3) / T0] × 100
(In the formula, T0 is an initial transmittance at a wavelength of 254 nm of an ultraviolet transmission filter having a protective film on one main surface of the glass plate having a thickness of 0.5 mm whose both surfaces are optically polished, and T3 is the ultraviolet ray. (Transmittance at a wavelength of 254 nm after irradiating the transmission filter with ultraviolet light having a wavelength of 254 nm with an intensity of 10 mW / cm ² from the main surface side provided with the protective film for 1000 hours.)

  In the ultraviolet transmission filter of the present invention, it is preferable that the glass plate has a transmittance at a wavelength of 254 nm of 80% or more in a spectral transmittance at a thickness of 0.5 mm.

In the ultraviolet transmission filter of the present invention, the glass preferably has an average coefficient of thermal expansion in a temperature range of 0 to 300 ° C. of 30 × 10 ^{−7 to} 90 × 10 ⁻⁷ / ° C.

  ADVANTAGE OF THE INVENTION According to this invention, the ultraviolet-ray permeable filter with the high transmittance | permeability of an ultraviolet-ray, especially deep ultraviolet light, and the deterioration of the transmittance | permeability was suppressed at the time of long-term use can be provided.

It is sectional drawing showing schematic structure of the ultraviolet-ray transmissive filter of embodiment.

Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG.
FIG. 1 is a cross-sectional view illustrating a schematic configuration of an ultraviolet transmission filter 1 according to an embodiment of the present invention. An ultraviolet transmission filter 1 shown in FIG. 1 includes a glass plate 2 and a protective film 3 on one main surface thereof. Hereinafter, the glass plate 2 and the protective film 3 constituting the ultraviolet transmission filter 1 will be described in detail.
(Glass plate)
The glass plate 2 used in the present embodiment is a main body constituting the ultraviolet transmission filter 1 and has good ultraviolet transmission characteristics. In order to satisfy such characteristics, it is an essential element that the glass plate 2 is formed of glass having the following composition and characteristics.
This glass plate 2 is expressed in terms of a molar percentage on the basis of oxide, and SiO ₂ is 55 to 80%, B ₂ O ₃ is 12 to 27%, R ₂ O (R is a group consisting of Li, Na, and K). 4 to 20%, Al ₂ O ₃ 0 to 5%, R′O (R ′ is selected from the group consisting of Mg, Ca, Sr and Ba). At least one alkaline earth metal) is formed from glass containing 0-5%, ZnO 0-5%, ZrO ₂ 0-20%, Ta ₂ O ₅ 0-5%. The
Moreover, the glass plate 2 is formed of glass having a transmittance of 70% or more at a wavelength of 254 nm in terms of spectral transmittance at a thickness of 0.5 mm.

  Since the glass plate 2 is made of glass having the above composition, it has a high transmittance of ultraviolet rays, particularly deep ultraviolet rays. Moreover, the coloring of the glass by ultraviolet irradiation can be suppressed by adjusting a composition. Hereinafter, each component of the glass used for this embodiment is demonstrated.

SiO ₂ is a component constituting the skeleton of the glass and is essential. When the content of SiO ₂ is less than 55%, the stability as glass is lowered or the weather resistance is lowered. The content of SiO ₂ is preferably 55.5% or more, more preferably 56% or more. If the content of SiO ₂ exceeds 80%, the viscosity of the glass melt increases and the meltability is significantly reduced. The content of SiO ₂ is preferably 77% or less, more preferably 75% or less.

Al ₂ O ₃ is a component that improves the weather resistance of the glass. When Al ₂ O ₃ is contained, if the content of Al ₂ O ₃ is more than 5%, the viscosity of the glass melt becomes high and uniform melting becomes difficult. When obtaining the effect of improving the weather resistance of the glass, the content of Al ₂ O ₃ is preferably 4.5% or less, more preferably 4.3% or less, and even more preferably 4% or less.

In the present embodiment, it is most preferable that Al ₂ O ₃ is not substantially contained, and the reason will be described below. In this specification unless containing _Al 2 _{O 3} substantially has the content of _Al 2 _{O 3} means that 0.01% or less.

The transmittance of deep ultraviolet rays in glass depends on the amount of non-crosslinked oxygen in the glass, and it is considered that the transmittance of deep ultraviolet rays decreases when the amount of non-crosslinked oxygen is large. Then, Al ₂ O ₃ is a component to reduce the non-bridging oxygen of the glass, it has been conventionally believed that glass having high transmittance deep ultraviolet By containing Al ₂ O ₃ is obtained. However, when the present inventors tested by changing Al ₂ O ₃ and other glass composition conditions, contrary to conventional technical common sense, the content of Al ₂ O ₃ is reduced as much as possible, preferably Al ₂ The inventors have found a new finding that, by not containing O ₃ , a glass having a high deep ultraviolet transmittance can be obtained. The mechanism is not known in detail, but is considered to be the following reason.

Al ₂ O ₃ is said to reduce uncrosslinked oxygen in the glass by forming a glass network structure with an alkali metal component in the glass. However, since glass is in an amorphous state, it is considered that the glass structure fluctuates. That is, by increasing the content of Al ₂ O _3, the amount of non-bridging oxygen in the glass tends to decrease on the average, but on the other hand, an Al component that does not form a network structure due to fluctuations in the structure unique to the amorphous state It cannot be denied that there is a possibility that the ratio of the presence of a modified oxide (structural defect) increases. It is considered that such a structural defect caused by an Al component that does not form a network structure forms an absorption band of light in the ultraviolet region, and the ultraviolet transmittance of the glass is lowered.

  In the present embodiment, the fact that a specific component is substantially not included means that it is not intentionally added, and it is inevitably mixed from raw materials and the like, and does not affect the intended characteristics. Is not to be excluded.

On the other hand, Al ₂ O ₃ is a component that suppresses coloring of glass by ultraviolet rays. If the content of Al ₂ O ₃ is less than 0.5%, the effect of suppressing the coloration of the glass by ultraviolet rays may not be sufficiently obtained depending on other compositions. The content of Al ₂ O ₃ is preferably 0.5% or more and 5% or less in terms of improving the effect of suppressing the coloring of the glass by ultraviolet rays.

B ₂ O ₃ is a component to improve the transmittance of deep ultraviolet, a component to suppress coloring due to ultraviolet rays of the glass and is essential. When the content of B ₂ O ₃ is less than 12%, a significant effect cannot be obtained with respect to the deep ultraviolet transmittance improvement. The content of B ₂ O ₃ is preferably 13% or more, more preferably 14% or more. If the content of B ₂ O ₃ exceeds 27%, striae due to volatilization occurs, and the yield decreases. The content of B ₂ O ₃ is preferably 26% or less, more preferably 25% or less.

R ₂ O (R represents at least one alkali metal selected from the group consisting of Li, Na, and K) is a component that improves the meltability of glass and is essential. When ΣR ₂ O (ΣR ₂ O is the total content of Li ₂ O, Na ₂ O and K ₂ O) is less than 4%, the meltability is poor. ΣR ₂ O is preferably 4.5% or more, more preferably 5% or more. When ΣR ₂ O exceeds 20%, the weather resistance decreases. ΣR ₂ O is preferably 18% or less, more preferably 16% or less.

R′O (R ′ represents at least one alkaline earth metal selected from the group consisting of Mg, Ca, Sr, and Ba) is a component that improves the meltability and is not essential. It can be contained if necessary. When R′O is contained, if ΣR′O (ΣR′O means the total content of MgO, CaO, SrO and BaO) exceeds 5%, the weather resistance is lowered. The content of ΣR′O is preferably 4% or less, more preferably 3% or less. Since R′O contains a relatively large amount of Fe ₂ O ₃ or TiO ₂ that causes a decrease in the transmittance of deep ultraviolet rays in the raw material, it is preferably not substantially contained.

  ZnO is a component that improves the weather resistance of the glass and reduces the degree of deterioration in the ultraviolet irradiation test, and can be contained as necessary. When ZnO is contained, if the ZnO content exceeds 5%, the devitrification characteristics of the glass deteriorate. The content of ZnO is preferably 4.5% or less, more preferably 4% or less.

ZrO ₂ is a component that improves the weather resistance of the glass and reduces the degree of deterioration in the ultraviolet irradiation test, that is, a component that suppresses the coloring of the glass by ultraviolet rays, and can be contained as necessary. When ZrO ₂ is contained, if the ZrO ₂ content exceeds 20%, the meltability of the glass may deteriorate. The content of ZrO ₂ is preferably 15% or less, more preferably 10% or less. Further, the content of ZrO ₂ is preferably 1.5% or more, more preferably 1.7% or more, and further preferably 1.8%, from the viewpoint of improving the effect of suppressing the coloring of the glass by ultraviolet rays. That's it.

Ta ₂ O ₅ is a component that improves the weather resistance of the glass and reduces the degree of deterioration in the ultraviolet irradiation test, that is, suppresses coloring of the glass due to ultraviolet rays, and is not essential, but may be contained as necessary. it can. When containing ta ₂ O _5, the content thereof exceeds 5%, the melting property deteriorates. The content of Ta ₂ O ₅ is preferably 0.01% or more, more preferably 0.02% or more, and further preferably 0.02% or more in terms of improving the effect of suppressing the coloring of the glass by ultraviolet rays. It is 03% or more, and particularly preferably 0.05% or more. Further, if the glass contains Ta ₂ O _5, the content thereof is preferably 3% or less, more preferably 2% or less.

Fe ₂ O ₃ is a component that absorbs deep ultraviolet rays and reduces the transmittance by being present in the glass. However, it is very difficult to completely avoid the incorporation of Fe ₂ O ₃ from the glass raw material or the manufacturing process. Therefore, if the content of Fe ₂ O ₃ is less than 0.00005%, the cost for glass production becomes high, such as using a refined high-cost glass raw material, which is not preferable. The content of Fe ₂ O ₃ is preferably 0.0001% or more. If the content of Fe ₂ O ₃ is more than 0.01%, the transmittance of deep ultraviolet rays is too low, which is not preferable. The content of Fe ₂ O ₃ is preferably 0.0065% or less, more preferably 0.005% or less.

TiO ₂ is, Fe ₂ O ₃ Similarly, the presence in the glass, which is a component that reduces the transmittance by absorbing deep UV. However, it is very difficult to completely avoid the mixing of TiO ₂ from the glass raw material and the manufacturing process. Therefore, if the content of TiO ₂ is less than 0.0001%, the cost for glass production becomes high, such as using a refined and high-cost glass raw material. The content of TiO ₂ is preferably 0.0003% or more. When the content of TiO ₂ is more than 0.02%, the transmittance of deep ultraviolet rays is too low, which is not preferable. The content of TiO ₂ is preferably 0.015% or less, more preferably 0.01% or less.

Cr ₂ O ₃ , NiO, CuO, CeO ₂ , V ₂ O ₅ , WO ₃ , MoO ₃ , MnO _2, and CoO all exist in the glass, thereby absorbing deep ultraviolet rays and reducing the transmittance. It is an ingredient. Therefore, it is preferable that these components are not substantially contained in the glass.
In the present specification, substantially not containing the above components means that Cr ₂ O ₃ is 0.01% or less, NiO is 0.01% or less, CuO is 0.01% or less, and CeO ₂ is 0.01%. %, V ₂ O ₅ is 0.01% or less, WO ₃ is 0.01% or less, MoO ₃ is 0.01% or less, MnO ₂ is 0.01% or less, and CoO is 0.01% or less. means.

  Since Cl may particularly increase the degree of deterioration at a wavelength of 254 nm in an ultraviolet irradiation test described later, it is preferable that Cl is not substantially contained in the glass. In the present specification, “substantially not containing Cl” means 0.01% or less.

  F is a component that volatilizes when the glass is melted, and striations may occur in the glass. Therefore, it is preferable that F is not substantially contained in the glass. In the present specification, substantially not containing F means 0.01% or less.

In addition, the glass used in this embodiment may contain SO ₃ or SnO ₂ for the purpose of fining.

  The glass used in the present embodiment has a transmittance of 70% or more at a wavelength of 254 nm in a spectral transmittance at a plate thickness of 0.5 mm of a single glass (without a protective film). By using the ultraviolet transmissive filter 1 using ultraviolet transmissive glass having such optical characteristics in an apparatus that utilizes deep ultraviolet rays, the apparatus can be operated efficiently. When the transmittance at a wavelength of 254 nm is less than 70% in the spectral transmittance at a glass plate thickness of 0.5 mm, the apparatus cannot be operated efficiently. The transmittance at a wavelength of 254 nm is preferably 72% or more, more preferably 75% or more, and most preferably 80% or more.

  Furthermore, the glass used in the present embodiment (a single glass (without a protective film)) has a degree of deterioration of transmittance of 30% or less at a wavelength of 254 nm measured by a weather resistance test as follows. preferable.

  In the weather resistance test, glass is cut into a plate having a side of 30 mm square, and a glass plate having both surfaces optically polished so as to have a thickness of 0.5 mm is manufactured. The initial transmittance (Tx) at a wavelength of 254 nm of this glass plate is measured. Next, the glass plate is held in a high-temperature and high-humidity (temperature 85 ° C., relative humidity 85%) atmosphere for 1000 hours. The transmittance (T4) at a wavelength of 254 nm of the glass plate after being kept in a high temperature and high humidity atmosphere for 1000 hours is measured. And the deterioration degree of the transmittance | permeability of wavelength 254nm is calculated | required from the following formula | equation (1) as a ratio of deterioration from the initial transmittance (Tx) before a weather resistance test.

  Degree of degradation by weather resistance test (%) = [(Tx−T4) / Tx] × 100 (1)

  Furthermore, it is preferable that the glass used in the present embodiment (single glass (without a protective film)) has a deterioration degree of transmittance of 15% or less at a wavelength of 254 nm measured by an ultraviolet irradiation test as follows. .

In the ultraviolet irradiation test, for example, a glass plate processed in the same manner as in the weather resistance test described above is used from the surface of the glass plate so that the ultraviolet irradiation intensity at a wavelength of 254 nm is 10 mW / cm ² using a high-pressure mercury lamp for physics and chemistry. A glass sample is irradiated for 1000 hours from the position where the distance of 15 cm is 15 cm. The transmittance (T3) at a wavelength of 254 nm of the glass plate after being irradiated with ultraviolet rays for 1000 hours is measured. And the deterioration degree of the transmittance | permeability of wavelength 254nm is calculated | required from the following formula | equation (2) as a ratio of deterioration from the initial transmittance (Tx) before ultraviolet irradiation.

  Degree of degradation by ultraviolet irradiation test (%) = [(Tx−T5) / Tx] × 100 (2)

The glass used in the present embodiment preferably has an average coefficient of thermal expansion of 30 × 10 ⁻⁷ / ° C. or more and 90 × 10 ⁻⁷ / ° C. or less in a temperature range of 0 ° C. or more and 300 ° C. or less. When the ultraviolet transmissive filter 1 including the glass plate 2 made of glass is used in, for example, an ultraviolet light source device, the glass plate 2 may be attached to a package material in order to hermetically seal the light source. Since the temperature of the ultraviolet light source increases with light emission, if the difference in the thermal expansion coefficient between the glass plate 2 and the package material is large, peeling or breakage may occur, and the airtight state of the light source may not be maintained. In consideration of heat resistance, the package material is made of a material such as glass, crystallized glass, ceramics, or alumina. And in order to make small the difference of the thermal expansion coefficient of a package material and the glass plate 2, the glass used for this embodiment has an average thermal expansion coefficient of 30 * 10 < ^-7 > / in the temperature range of 0 degreeC or more and 300 degrees C or less. It is preferable that it is not lower than 90 ° C. and not higher than 90 × 10 ⁻⁷ / ° C. When the average thermal expansion coefficient of this glass is outside the above-mentioned temperature range, the difference in thermal expansion coefficient between the package material and the glass plate 2 is large, and there is the above-mentioned concern when using the ultraviolet light source device.

Moreover, the difference of the average thermal expansion coefficient of the temperature range of 0 degreeC or more and 300 degrees C or less of the glass plate 2 used for this embodiment and the member joined to the said glass plate 2 is 20x10 < ^-7 > / degrees C or less. Is preferably 10 × 10 ⁻⁷ / ° C. or less, and most preferably 5 × 10 ⁻⁷ / ° C. or less.

  The thickness of the glass plate 2 can be appropriately designed according to the application, and is, for example, 0.1 mm or more and 10 mm or less. If the thickness of the glass plate 2 exceeds 10 mm, sufficient ultraviolet transmittance may not be obtained. If the thickness of the glass plate 2 is less than 0.1 mm, the strength of the glass plate 2 may not be sufficient depending on the application.

  The glass used in this embodiment is manufactured as follows. First, the glass raw material for comprising each component of a desired composition is prepared. As the glass raw material used in the present embodiment, any form of compounds such as oxides, hydroxides, carbonates, sulfates, nitrates, fluorides and chlorides can be used.

  Next, these glass raw materials are prepared so as to be a glass having a desired composition, and are put into a melting tank. The melting tank is a container of material selected from platinum or platinum alloy refractories. In the present embodiment, the platinum or platinum alloy container is a platinum group element such as platinum (Pt), iridium (Ir), palladium (Pd), rhodium (Rh), or the like, and in addition to the platinum group element, gold (Au). It is a metal or alloy container selected from the group consisting of alloys including elements, and can withstand high temperature melting.

  By removing bubbles and striae in a defoaming tank or a stirring tank disposed on the downstream side of the glass melted in the melting tank, a homogenized high-quality glass with few glass defects is obtained. Can do. The glass described above is allowed to flow out into a mold through a nozzle or the like, cast into a mold, rolled out, drawn out into a plate shape, and formed into a predetermined shape. The slowly cooled glass is subjected to slicing, polishing, and the like to obtain a glass having a predetermined shape.

(Protective film)
The ultraviolet transmission filter 1 of the present embodiment includes a protective film 3 on at least one main surface of the glass plate 2. The protective film 3 provides the ultraviolet light transmitting filter 1 with at least one function selected from weather resistance, alkali resistance, acid resistance, and chemical resistance, and suppresses a decrease in ultraviolet light transmittance after long-term use. Have The protective film 3 has ultraviolet transparency that suppresses reflection of deep ultraviolet light, for example, ultraviolet light having a wavelength of about 254 nm, and improves its transmittance more than the transmittance of the glass plate 2 alone. Furthermore, it is preferable that the protective film 3 has a function of imparting weather resistance to the ultraviolet transmission filter 1 and suppressing a decrease in ultraviolet transmittance after long-term use. The protective film 3 preferably has a function of imparting ultraviolet resistance to the ultraviolet transmission filter 1 and suppressing a decrease in ultraviolet transmittance after long-term use. In the ultraviolet transmission filter 1, the protective film 3 is provided on one main surface of the glass plate 2, but may be provided on both main surfaces of the glass plate 2.

  The ultraviolet transmission filter 1 includes the protective film 3 so that the weather resistance in a high temperature and high humidity atmosphere is improved. Moreover, it is preferable that the protective film 3 selectively reflects ultraviolet rays having a wavelength of 200 to 230 nm. The glass plate 2 may change its glass structure due to ultraviolet rays having a wavelength of 200 to 230 nm. As a result, the glass may be colored and the ultraviolet transmittance may be deteriorated. By selectively reflecting ultraviolet rays having a wavelength of 200 to 230 nm among the light reaching the glass plate 2 by the protective film 3, the ultraviolet transmissive filter 1 having the protective film 3 is irradiated with ultraviolet rays for a long time. It is considered that the decrease in transmittance is suppressed.

  The optical properties of the protective film 3 are preferably such that the average transmittance of the protective film 3 at a wavelength of 200 nm to 230 nm is 75% or less from the viewpoint of suppressing ultraviolet light transmission at a wavelength of 254 nm and coloring of the glass by ultraviolet light. The average transmittance of the protective film 3 with a wavelength of 200 nm to 230 nm can be measured, for example, by the following method. First, the spectral transmittance of the ultraviolet transmission filter 1 (the glass plate 2 provided with the protective film 3) is measured using an ultraviolet visible near infrared spectrophotometer. Next, the spectral transmittance of only the glass plate 2 is measured using an ultraviolet-visible near-infrared spectrophotometer. Next, the spectral transmittance of only the protective film 3 is calculated from the spectral transmittance of only the glass plate 2 and the spectral transmittance of the ultraviolet transmission filter 1. And the average transmittance | permeability of wavelength 200nm -230nm is computed from the spectral transmittance of only the protective film 3. FIG.

As the protective film 3, for example, a dielectric multilayer film, a single layer film, a film mainly composed of silica (SiO ₂ ), or the like can be used. The protective film may be a single layer film or a multi-layered film in which two or more layers are laminated.

  The dielectric multilayer film is a film having an optical function obtained by alternately laminating a low refractive index dielectric film (low refractive index film) and a high refractive index dielectric film (high refractive index film). . Depending on the design, it can be used as an antireflection film, a reflection film, a selective wavelength shielding film, or the like that expresses the function of controlling the transmission and shielding of light in a specific wavelength region by utilizing light interference. The low refractive index and the high refractive index mean that the refractive index has a high refractive index and a low refractive index with respect to the refractive index of the adjacent layer.

  For the high refractive index material constituting the high refractive index film and the low refractive index material constituting the low refractive index film, two types of materials having different refractive indexes are prepared, and the material having a high refractive index is changed to the high refractive index material and the refractive index. A material having a low refractive index may be a low refractive index material.

  Specifically, a dielectric multilayer using a material having a refractive index of 1.3 to 1.6 as a low refractive index material and a material having a refractive index of 2.0 to 2.3 as a high refractive index material. Forming a film is preferable from the viewpoint of ease of design and ease of manufacture.

More specifically, examples of the low refractive index material include SiO ₂ , SiO _x N _y , and MgF ₂ . Among these, in the present embodiment, a low refractive index material within the above refractive index range is preferable, and SiO ₂ is particularly preferable in terms of reproducibility, stability, economy, and the like in film formability.

More specific examples of the high refractive index material include HfO ₂ , Al ₂ O ₃ , ZrO ₂ , and YbF ₃ . Further, as a high refractive index material, aluminum lanthanum oxide _{(Al x La y O z)} , may be used aluminum tantalum oxide _(Al x _Ta y _{O z)} alloy oxide evaporation material, such as. Among these, in the present embodiment, a high refractive index material within the above refractive index range is preferable, and the film forming property, the refractive index, and the like are comprehensively determined including their reproducibility and stability, and HfO ₂ Al ₂ O _{3 and the} like are particularly preferably used.

  The dielectric multilayer film can be designed using a conventional method in accordance with the required optical characteristics, and the specific number of layers and film thickness, and the refractive index of the high refractive index material and low refractive index material to be used. Furthermore, the dielectric multilayer can be manufactured as per the design.

  The number of layers of the dielectric multilayer film depends on the optical properties of the dielectric multilayer film, but the total number of layers of the low refractive index film and the high refractive index film is preferably 2 to 100, more preferably 2 to 80. When the total number of stacked layers is larger, the transmittance of ultraviolet rays of 200 nm to 230 nm, particularly 200 nm to 215 nm, can be reduced, so that coloring of the glass by ultraviolet rays can be suppressed. If the total number of laminated layers is too large, the tact time during production becomes long, warping of the dielectric multilayer film occurs, and the film thickness of the dielectric multilayer film tends to increase. In addition, as long as it has the optical characteristic calculated | required, it is preferable that there are few layers. If the order of lamination of the low refractive index film and the high refractive index film is alternate, the first layer may be a low refractive index film or a high refractive index film, but a high refractive index film is preferred.

  The dielectric multilayer film can be manufactured by, for example, a dry film forming process such as an IAD (Ion Assisted Deposition) vapor deposition method, a CVD method, a sputtering method, or a vacuum vapor deposition method.

  When a dielectric multilayer film is formed as the protective film 3, the thickness of the dielectric multilayer film is preferably 60 nm or more and 300 nm or less, more preferably 90 nm or more and 150 nm or less in terms of imparting excellent durability to the ultraviolet transmission filter 1. preferable. If the thickness of the dielectric multilayer film is less than 60 nm, sufficient ultraviolet light transmission and durability may not be obtained, and if it exceeds 300 nm, sufficient ultraviolet light transmission may not be obtained. The film thickness of the dielectric multilayer film can be measured with a stylus film thickness meter. If there are fine holes in the dielectric film, moisture or the like may enter from there, and the surface of the glass plate 2 may be altered. In this embodiment, the protective film 3 is preferably a dielectric film composed of multiple layers, that is, a dielectric multilayer film in terms of suppressing this.

When a single layer film is used as the protective film 3, the material of the protective film 3 includes silicon oxide (SiO ₂ ), silicon nitride (Si ₃ N ₄ ), silicon oxynitride (Si ₄ O ₅ N ₃ ), aluminum oxide (Al ₂ O ₃ ), zirconium oxide (ZrO ₂ ), titanium oxide (TiO ₂ ), tantalum oxide (Ta ₂ O ₅ ), and magnesium fluoride (MgF ₂ ) can be used. The material of the single layer film may be one kind of the above-mentioned substances or two or more kinds. By using the single layer film made of the above-described substance, it is possible to impart excellent weather resistance and alkali resistance to the ultraviolet transmission filter 1. The film thickness of the single layer film is preferably 5 nm to 500 nm, and more preferably 25 nm to 300 nm. If the film thickness of the single layer film is less than 5 nm, sufficient weather resistance and alkali resistance may not be obtained. If it exceeds 500 nm, it takes time to form the single layer film, and productivity may be deteriorated. The film thickness of the single layer film can be measured with a stylus type film thickness meter.

  This single-layer film can be manufactured by a known process such as, for example, an IAD (Ion Assisted Deposition) vapor deposition method, a CVD method, a sputtering method, a vacuum vapor deposition method, a sol-gel method, an atomic layer deposition method (Atomic Layer Deposition method), or the like. it can.

When the protective film 3 is made of a film containing SiO ₂ as a main component, the protective film 3 contains 90% by mass or more of SiO ₂ in the film (100% by mass). Note that film composed mainly of SiO ₂ is more preferably substantially consisting of SiO ₂ film, and wherein substantially composed of SiO ₂ film, it is composed of only SiO ₂ except for incidental impurities Means that.

When the protective film 3 is made of a film containing SiO ₂ as a main component, the protective film 3 preferably contains hollow silica particles. In this case, the protective film 3 may be composed only of a film containing hollow silica particles, and a film not containing hollow silica particles (silica undercoat described later) and a film containing hollow silica particles are laminated. And may be configured. The membrane containing hollow silica particles is formed by laminating two or more membranes containing hollow silica particles, for example, laminated in different modes (membranes having different contents of hollow silica particles, different average primary particle sizes, etc.). It may be. By making the protective film 3 have such a laminated structure, the transmittance of ultraviolet rays having a desired wavelength in the protective film 3 can be adjusted by design. For this reason, the laminated structure can impart excellent ultraviolet transparency and weather resistance to the protective film 3.

The membrane containing hollow silica particles is preferably constituted by dispersing hollow silica particles in a matrix. The hollow silica particles are fine particles having voids inside the SiO ₂ outer shell. In the hollow silica particles, each particle may exist in an independent state, each particle may be linked in a chain shape, or each particle may be aggregated. The average primary particle diameter of the hollow silica particles is preferably 5 nm to 150 nm, and more preferably 50 nm to 100 nm. When the average primary particle diameter of the hollow silica particles is within the above range, the ultraviolet ray transparency of the protective film 3 is excellent.

  The average primary particle size of the hollow silica particles is obtained by randomly selecting 100 fine particles from an electron micrograph, measuring the particle size of each fine particle, and averaging the particle size of the 100 fine particles.

  Examples of the matrix include a calcined product of an alkoxysilane hydrolyzate (sol-gel silica) and a silazane calcined product, and a calcined product of an alkoxysilane hydrolyzate is more preferable. As a catalyst used for hydrolysis of alkoxysilane, a catalyst that does not hinder the dispersion of the hollow silica particles is preferable.

  Examples of the alkoxysilane include tetraalkoxysilane (for example, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, etc.), and an alkoxysilane having a perfluoropolyether group (for example, perfluoropolyethertriethoxysilane). , Alkoxysilane having a perfluoroalkyl group (for example, perfluoroethyltriethoxysilane), alkoxysilane having a vinyl group (for example, vinyltrimethoxysilane, vinyltriethoxysilane, etc.), alkoxysilane having an epoxy group (for example, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glyci Trimethoxy silane, etc.), alkoxysilanes (e.g. having an acryloyloxy group, 3-acryloyloxy propyl trimethoxysilane), and the like.

In the case of tetraalkoxysilane, hydrolysis of the alkoxysilane is carried out using 4 times or more moles of water of the alkoxysilane and an acid or alkali as a catalyst. Examples of the acid include inorganic acids (eg, HNO ₃ , H ₂ SO ₄ , HCl, etc.) and organic acids (eg, formic acid, oxalic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, etc.). Examples of the alkali include ammonia, sodium hydroxide, potassium hydroxide and the like. The catalyst is preferably an acid from the viewpoint of long-term storage stability of the hydrolyzate of alkoxysilane.

  A film containing hollow silica particles can be produced, for example, by applying a coating solution for forming a film containing hollow silica particles on a glass plate, preheating as necessary, and finally baking. In the present embodiment, “baking” includes heating and curing a coating film obtained by coating a coating liquid on the transparent substrate surface.

  Examples of the coating liquid include a mixture of a dispersion of hollow silica particles and a solution of a matrix precursor (for example, a hydrolyzate solution of alkoxysilane, a solution of silazane, etc.). The coating solution may contain a surfactant for improving the leveling property, a metal compound for improving the weather resistance of the coating film, and the like.

  Examples of the dispersion medium for the dispersion of the hollow silica particles include water, alcohols, ketones, ethers, cellosolves, esters, glycol ethers, nitrogen-containing compounds, sulfur-containing compounds and the like.

  As the solvent of the alkoxysilane hydrolyzate solution, a mixed solvent of water and alcohols (for example, methanol, ethanol, isopropanol, butanol, diacetone alcohol, etc.) is preferable.

  As a coating method, a wet coating method (for example, spin coating method, spray coating method, dip coating method, die coating method, curtain coating method, screen coating method, ink jet method, flow coating method, gravure coating method, bar coating method, flexographic method). Coating methods, slit coating methods, roll coating methods, etc.), and known methods can be used. The coating temperature is preferably room temperature to 200 ° C, more preferably room temperature to 150 ° C.

  The firing temperature is preferably 30 ° C. or higher, more preferably 200 ° C. or higher and the glass softening point temperature or lower. When the firing temperature is 200 ° C. or higher, the weather resistance is improved. If the baking temperature is not higher than the softening point temperature of glass (for example, not higher than 800 ° C.), the vacancies in the protective film 3 are not lost, and the reflectance of ultraviolet rays is sufficiently low.

  When forming a film containing hollow silica particles as the protective film 3, the film thickness of the film containing hollow silica particles is preferably 30 nm to 150 nm in terms of imparting excellent durability to the ultraviolet transmission filter 1, and 40 nm. ˜100 nm is more preferable.

  When the protective film 3 has a film (silica undercoat) that does not contain hollow silica particles, the silica undercoat is preferably formed between the glass plate 2 and the film containing hollow silica particles.

  The silica undercoat is preferably composed of a matrix that does not contain hollow silica particles. Examples of the silica undercoat include a calcined product of a hydrolyzate of alkoxysilane (sol-gel silica), a calcined product of silazane, and the like, similar to the matrix of the membrane containing the hollow silica particles. The silica undercoat is formed by applying a dispersion of a matrix precursor solution (for example, an alkoxysilane hydrolyzate solution, silazane solution, etc.) on a glass plate in the same manner as described above, followed by baking. be able to.

  The firing temperature for forming the silica undercoat is preferably 30 ° C to 300 ° C. Further, a dispersion for forming a silica undercoat is applied on a glass plate, pre-baked (remaining heat), and a dispersion for forming a film containing the hollow silica particles on the coating film obtained thereby. The silica undercoat and the film containing the hollow silica particles can be co-fired by applying and baking, for example, at 200 ° C. or higher. Thereby, a silica undercoat can be densified and the weather resistance of the protective film 3 can be improved.

  The film thickness of the silica undercoat is preferably 30 nm to 150 nm, and more preferably 40 nm to 100 nm, from the viewpoint of imparting excellent ultraviolet transparency and durability to the protective film 3.

When the protective film 3 is made of a film containing SiO ₂ as a main component, the thickness of the protective film 3 is preferably 30 nm to 200 nm, and more preferably 40 nm to 150 nm, in order to obtain excellent ultraviolet light transmittance and durability. . The thickness of the protective film 3 made of a film containing SiO ₂ as a main component can be measured from an image obtained by observing the cross section of the protective film with a scanning electron microscope. The thickness of the membrane containing the hollow silica particles and the thickness of the silica undercoat can be measured similarly.

When the protective film 3 is formed as a single-layer film of SiO ₂ described above, the single-layer film of SiO ₂ does not have pores independent of the film containing the hollow silica particles and the silica undercoat. Since the configuration is different in this respect, these can be distinguished. The membrane and the silica undercoat containing the hollow silica particles have independent pores and do not have pores communicating from the surface of the protective film 3 to the glass plate 2. The presence / absence of the holes can be confirmed from an image obtained by observing the cross section of the protective film 3 with a scanning electron microscope.

  The ultraviolet transmission filter 1 of this embodiment preferably has an average transmittance of a wavelength of 200 to 230 nm of 60% or less in terms of spectral transmittance. By using the ultraviolet transmissive filter 1 having such optical characteristics in an apparatus that utilizes deep ultraviolet rays, the apparatus can be operated efficiently and deterioration of ultraviolet transmittance after long-term use can be suppressed. If the average transmittance at a wavelength of 200 to 230 nm exceeds 60% in the above spectral transmittance, the ultraviolet transmittance may deteriorate after long-term use. The average transmittance at a wavelength of 200 to 230 nm is more preferably 58% or less, still more preferably 55% or less, and particularly preferably 50% or less.

  The ultraviolet transmission filter 1 of the present embodiment is preferably provided with a protective film on one main surface, and the transmittance at a wavelength of 254 nm is 80% or more in the spectral transmittance when the glass plate thickness is 0.5 mm. . By using the ultraviolet light transmitting filter 1 having such optical characteristics in a device that utilizes deep ultraviolet rays, the device can be operated efficiently. When the glass plate thickness is 0.5 mm, if the transmittance at a wavelength of 254 nm in spectral transmittance is less than 80%, the apparatus may not be operated efficiently. The transmittance at a wavelength of 254 nm is preferably 81% or more, more preferably 83% or more, and most preferably 85% or more.

  In addition, when providing the protective film 3 in both the main surfaces of the glass plate 2, in the spectral transmittance when a glass plate thickness is 0.5 mm, the average transmittance of wavelength 200-230 nm and the transmittance of wavelength 254 nm If it is the said range, the said effect can be acquired similarly to the ultraviolet-ray transmissive filter 1 provided with the protective film 3 on one main surface of the glass plate 2. FIG.

  As for the ultraviolet transmission filter 1 of this embodiment, it is preferable that the deterioration degree of the transmittance | permeability of wavelength 254nm measured by a weather resistance test (1000 hours) is 5% or less as follows.

  In the weather resistance test, for example, a glass plate 2 having a thickness of 0.5 mm that is optically polished on both sides is used, a protective film 3 is formed on one main surface of the glass plate 2, and an ultraviolet transmission filter is formed. To manufacture. The ultraviolet transmissive filter produced in the same manner as described above is kept for 1000 hours in a high temperature and high humidity (temperature 85 ° C., relative humidity 85%) atmosphere. The transmittance (T1) at a wavelength of 254 nm of the ultraviolet transmission filter after being kept in a high temperature and high humidity atmosphere for 1000 hours is measured. And the deterioration degree of the transmittance | permeability of wavelength 254nm is calculated | required from the following formula | equation (3) as a deterioration rate from the initial transmittance (T0) before a weather resistance test.

  Degree of deterioration by weather resistance test (%) = [(T0−T1) / T0] × 100 (3)

  As for the ultraviolet transmission filter 1 of this embodiment, it is preferable that the deterioration degree of the transmittance | permeability of wavelength 254nm measured by a weather resistance test (500 hours) is 3% or less as follows.

  In this weather resistance test, for example, a glass plate 2 having a thickness of 0.5 mm with both surfaces optically polished is used, a protective film 3 is formed on one main surface of the glass plate 2, and an ultraviolet transmission filter is formed. To manufacture. The ultraviolet transmissive filter manufactured in the same manner as described above is held for 500 hours in a high temperature and high humidity (temperature 85 ° C., relative humidity 85%) atmosphere. The transmittance (T2) at a wavelength of 254 nm of the ultraviolet transmission filter after being held in a high temperature and high humidity atmosphere for 500 hours is measured. Then, as the rate of deterioration from the initial transmittance (T0) before the weather resistance test, the value of T2 is used instead of the value of T1 in the above equation (3), and the degree of deterioration of the transmittance at a wavelength of 254 nm is obtained. It is done.

  In the ultraviolet transmission filter of the present embodiment, it is preferable that the degree of deterioration of transmittance at a wavelength of 254 nm measured by performing an ultraviolet irradiation test from the main surface side where the protective film 3 is provided is 5% or less.

In the ultraviolet irradiation test, the initial transmittance (T0) at a wavelength of 254 nm of an ultraviolet transmission filter manufactured in the same manner as described above is measured. Subsequently, using a high-pressure mercury lamp for physics and chemistry, the protective film 3 of the ultraviolet light transmitting filter is applied from the position where the distance from the glass plate surface is 15 cm so that the ultraviolet irradiation intensity is 10 mW / cm ² with the ultraviolet ray having a wavelength of 254 nm. Irradiate the principal surface side of the one provided with 1000 hours. The transmittance (T3) at a wavelength of 254 nm of the ultraviolet transmission filter after irradiation with ultraviolet rays for 1000 hours is measured. Then, the degree of deterioration of the transmittance at a wavelength of 254 nm is obtained from the following equation (4) as the deterioration rate from the initial transmittance (T0) before the ultraviolet irradiation.

  Degree of deterioration by ultraviolet irradiation test (%) = [(T0−T3) / T0] × 100 (4)

  In addition, when providing the protective film 3 in both the main surfaces of the glass plate 2, if the deterioration degree by the weather resistance test measured from the any one protective film 3 side is the said range, one side of the glass plate 2 The above effect can be obtained in the same manner as the ultraviolet light transmitting filter 1 having the protective film 3 on the main surface. Similarly, with respect to the degree of deterioration in the ultraviolet irradiation test, if the degree of deterioration measured by irradiating ultraviolet rays from either one of the protective films 3 for 1000 hours is within the above range, it is applied to one main surface of the glass plate 2. The above effect can be obtained in the same manner as the ultraviolet transmission filter 1 including the protective film 3.

  The ultraviolet transmission filter 1 of the present embodiment is preferably used for an apparatus using an ultraviolet light source (for example, a UV-LED, a UV laser, etc.), a support substrate for manufacturing a semiconductor wafer on the premise of UV peeling, an arc tube, and the like. Can do. Examples of the device include, but are not limited to, a curing device for an ultraviolet curable resin composition, a light source cover glass for an ultraviolet sensor, and a water sterilization device. Moreover, the ultraviolet transmissive filter 1 of this embodiment is not limited to a plate shape, and can be used in an appropriate shape such as a tubular shape or a molded body depending on the application.

  For example, in a UV-LED device, a UV-LED chip serving as a light source is installed and electrically connected to a recess or a flat surface of a package made of a base material such as resin, metal, or ceramics. A transparent material having UV transparency is used as the light emission side window material, and the light emission side window material and the base material are hermetically sealed. The UV-LED device generates heat simultaneously with UV emission. Therefore, the transparent material may be deteriorated by heat, and the ultraviolet transmittance may be lowered.

  However, by using the ultraviolet transmission filter 1 of the present embodiment as a transparent material, the ultraviolet transmittance is not lowered even when used for a long time. Moreover, since the difference in the thermal expansion coefficient between the packaging material and the glass plate 2 can be reduced by using the glass plate 2 having the adjusted thermal expansion coefficient, the UV-LED is less susceptible to product cracking and cracking. A device can be provided.

  For example, in a UV laser device, a UV laser serving as a light source is installed and electrically connected to a recess or a plane of a package made of a base material such as a metal or a ceramic such as AlN. A transparent material having UV transparency is used as the light emission side window material, and the light emission side window material and the base material are hermetically sealed. In the UV laser device, heat generation occurs simultaneously with UV emission. Therefore, the transparent material may be deteriorated by heat, and the ultraviolet transmittance may be lowered. Further, if there is a large difference in the thermal expansion coefficient between the base material and the transparent material, cracks and cracks occur at the joint between the base material and the transparent material, and the product reliability is significantly reduced.

  However, by using the ultraviolet transmission filter 1 of the present embodiment as a transparent material, the ultraviolet transmittance is not lowered even when used for a long time. Moreover, in this embodiment, the difference of the thermal expansion coefficient of a base material and a transparent material can be improved by using the ultraviolet transmissive filter 1 which has the glass plate 2 by which the thermal expansion coefficient was controlled, and it is a crack of a product. Further, it is possible to provide a UV laser device with less occurrence of cracks.

  For example, for water sterilization, a light source is used in which a substrate on which UV-LEDs are arranged in a line is enclosed in a glass tube having UV transparency. Here, it is possible to provide a tubular UV-LED light source having a high deep ultraviolet light transmittance and a high bactericidal property by using a tube-molded ultraviolet transmissive filter 1 instead of the glass tube.

  In addition, since the light source used for water sterilization is used in the state immersed in water or the state which touches water, moisture resistance is calculated | required. According to the ultraviolet transmissive filter 1 of the present embodiment, a decrease in the ultraviolet transmittance when used for a long time in such an environment can be suppressed. In addition, the temperature difference between the inner surface of the tube heated by the heat generated from the light source and the outer surface of the tube in contact with water may increase. Therefore, from the viewpoint of preventing breakage of the tube due to heat shock, it is desirable that the glass constituting the tube has a low coefficient of thermal expansion, and the ultraviolet transmission filter 1 of this embodiment is also suitable in this respect.

When the ultraviolet transmissive filter 1 of the present embodiment is used for this application, the glass plate 2 preferably has an average coefficient of thermal expansion of 70 × 10 ⁻⁷ / ° C. or lower in a temperature range of 0 ° C. or higher and 300 ° C. or lower. It is more preferably 60 × 10 ⁻⁷ / ° C. or less, and further preferably 50 × 10 ⁻⁷ / ° C. or less.

  Further, for water sterilization, a light source in which a UV-LED array in which UV-LEDs are arranged in a line is attached between a plurality of glass plates is used. Here, it can replace with a glass plate and can provide the plate-shaped UV-LED array with the high transmittance | permeability of deep ultraviolet rays, and a high bactericidal property by using the ultraviolet transmissive filter 1 of this embodiment.

  For example, a UV tube having a UV light source mounted in a glass tube is used as the UV tube. Here, it is possible to provide an arc tube having a high transmittance of deep ultraviolet rays by using a tube formed with the ultraviolet transmission filter 1 of this embodiment instead of the glass tube.

  For example, in a semiconductor wafer manufacturing process, a support substrate is used for back grinding of silicon (Si). By making the silicon substrate thinner using the support substrate, it contributes to the demand for smaller and thinner chips in mobile phones, digital AV devices, IC cards, and the like. Currently, a reclaimed Si substrate is often used as a support substrate used for backgrinding of semiconductor wafers, etc., but the processing time becomes longer because the peeling method after backgrinding is limited to heat treatment and physical treatment. , Have problems such as poor yield.

  The above problems can be solved by using, as a support substrate, the ultraviolet light transmitting filter 1 having the glass plate 2 controlled in the above range of the thermal expansion coefficient of the present embodiment. That is, an ultraviolet transmission filter 1 in which a protective film 3 is formed on a glass plate 2 having a thermal expansion coefficient combined with silicon is used as a support substrate, and is bonded to a silicon substrate with an ultraviolet curable resin (compound having an ultraviolet absorbing structure) or the like. After matching, do back grinding. Then, after back grinding, the support substrate can be easily and quickly peeled by exposing to high-intensity ultraviolet rays to reduce the adhesiveness of the ultraviolet curable resin. Furthermore, the processing time is shortened, which can contribute to the improvement of yield.

  Furthermore, the ultraviolet transmission filter 1 of the present embodiment can be suitably used for a cell culture container or a member for observing and measuring cells (a bioanalytical instrument). In the field of cell culture, as a technique for observing cells, a technique for observing fluorescence by expressing a fluorescent protein in a desired cell or introducing a fluorescent dye is used. The ultraviolet transmissive filter of the present embodiment has a small fluorescence emitted from the glass itself constituting the ultraviolet transmissive filter 1, so that the fluorescence emitted when used as a container or member is small, and the weak fluorescence emitted from cells is measured with high accuracy. be able to. Examples of such containers and members include cover glasses, slide glasses, cell culture dishes, well plates, microplates, cell culture containers, analysis chips (biochips, microchemical chips), microchannel devices, and the like. However, it is not limited to these.

  Hereinafter, the present invention will be described based on examples. Examples 1 to 11 are examples of the present invention. The sample used for each example was produced as follows.

[Production of glass plate]
First, a glass raw material was prepared so as to have the glass composition shown in Table 1, and this glass raw material preparation was heated to 1300 ° C. or higher and 1650 ° C. or lower in an electric furnace using a platinum crucible and molybdenum silicide as a heating element. The mixture was melted, stirred and clarified for 5 hours. The melt was cast into a cast iron mold and slowly cooled to obtain 800 g of a glass sample (glass block). The glass block was sliced and polished. In the polishing process, both surfaces were optically polished to obtain glass plates (glasses A to E) having a predetermined shape (30 mm × 30 mm × 0.5 mm).

  About the obtained glass plate (without a protective film), as described later, the average transmittance of light having a wavelength of 200 to 230 nm when the glass plate thickness is 0.5 mm, the transmittance of wavelength 254 nm when the glass plate thickness is 0.5 mm, and ultraviolet irradiation Each measurement and evaluation of the deterioration degree of the transmittance at a wavelength of 254 nm by the test and the deterioration degree of the transmittance at a wavelength of 254 nm by the weather resistance test (1000 hours) were performed. These results are shown in the lower column of Table 1. In each glass plate, the transmittance at a wavelength of 254 nm before the ultraviolet irradiation test is different from the transmittance at a wavelength of 254 nm before the weather resistance test. This is due to variations in the thickness of the glass plate and measurement errors.

(Transmissivity at a glass plate thickness of 0.5 mm)
The transmittance of the glass was measured using an ultraviolet-visible near-infrared spectrophotometer (manufactured by JASCO Corporation, model number: V-570) as an average transmittance of ultraviolet light having a wavelength of 200 to 230 nm and a transmittance of 254 nm. The average transmittance at a wavelength of 200 to 230 nm was calculated as an average value of transmittance values every 1 nm at a wavelength of 200 to 230 nm.

(Deterioration degree of transmittance by weather resistance test (1000 hours))
The glass plate obtained above was held for 1000 hours in a high temperature and high humidity (temperature 85 ° C., relative humidity 85%) atmosphere. The transmittance at a wavelength of 254 nm before and after the weather resistance test was measured with the same ultraviolet-visible near-infrared spectrophotometer as described above, and the degree of deterioration was calculated by the following formula.

  Degree of transmittance deterioration by weather resistance test (%) = [(transmittance before weather resistance test−transmittance after weather resistance test) / transmittance before weather resistance test] × 100

(Degree of deterioration of transmittance by UV irradiation test)
The degree of transmittance deterioration by the ultraviolet irradiation test was measured as follows. About the said glass plate, the transmittance | permeability of wavelength 254nm was measured with the same ultraviolet visible near-infrared spectrophotometer. Next, a high-pressure mercury lamp for physics and chemistry (manufactured by Harrison Toshiba Lighting Co., model number: H-400P, output 400 W) is used as an ultraviolet light source, and ultraviolet light having a wavelength of 254 nm is applied to a glass plate so that the irradiation intensity is 10 mW / cm ^2. The glass plate was irradiated for 1000 hours from a position at a distance of 15 cm from the surface. Then, the transmittance | permeability of wavelength 254nm of a glass plate was again measured with the ultraviolet visible near-infrared spectrophotometer similar to the above similarly to the above. And the change of the transmittance | permeability in wavelength 254nm of the glass plate before and behind an ultraviolet irradiation test was compared. The degree of deterioration (%) was calculated by the following formula.

  Degree of transmittance deterioration (%) by UV irradiation test = [(Transmission before UV irradiation−Transmission after UV irradiation) / Transmission before UV irradiation] × 100

(Examples 1 to 10)
[Manufacture of UV transmission filter]
For each of the glass plates (glasses A to E) obtained above, in Examples 1 to 5, (1) a protective film (dry coat) comprising a dielectric multilayer film in which hafnium oxide and silicon oxide are alternately laminated In Examples 6 to 10, (2) a protective film (wet coat) containing hollow silica particles was formed as follows to produce an ultraviolet transmission filter. The protective film was formed on both main surfaces of the glass plate.

(Protective film formation method)
(1) Dry coating From the glass plate side, a 9.71 nm thick hafnium oxide film (HfO ₂ ), a 19.33 nm thick silicon oxide film (SiO ₂ ), and a 28.38 nm thick hafnium oxide film (HfO _2). ), A total of four layers of a high refractive index film and a low refractive index film of a 48.47 nm-thickness silicon oxide film (SiO ₂ ) were formed by vacuum deposition. In this way, an ultraviolet transmission filter having a protective film made of a dielectric multilayer film was obtained.

(2) Wet coat A dispersion of a hydrolyzed condensate of tetraethoxysilane was prepared. As a dispersion medium of the dispersion, a mixed solvent of ethanol, isopropanol, and methyl ethyl ketone was used. The dispersion of the tetraethoxysilane hydrolyzed condensate was applied on the main surface of the glass substrate by dip coating, and then pre-baked in a preheating furnace at 200 ° C. for 1 minute. On the surface of the coating film after calcination, the dispersion of the tetraethoxysilane hydrolyzed condensate is dispersed in an aqueous dispersion of hollow silica particles (trade name; Lucidia 4111, manufactured by JGC Catalysts & Chemicals, average primary of hollow silica particles. A coating solution mixed with a particle diameter of 60 nm was applied by a dip coating method, and baked in a baking furnace at 650 ° C. for 10 minutes. The content ratio of the hollow silica particles in the coating solution was 50 parts by mass with respect to 100 parts by mass of the tetraethoxysilane hydrolysis condensate in terms of SiO ₂ . In this way, an ultraviolet transmission filter having a protective film composed of a silica undercoat having a thickness of 50 nm and a hollow silica particle having a thickness of 50 nm on the silica undercoat was obtained on the main surface of the glass plate. .

  The obtained ultraviolet transmission filter was irradiated with ultraviolet rays from one main surface side where the protective film was formed, and similarly to the above, the average transmittance at a wavelength of 200 to 230 nm, the transmittance at a wavelength of 254 nm, and the wavelength by an ultraviolet irradiation test. Each measurement and evaluation of the deterioration degree of the transmittance at 254 nm and the deterioration degree of the transmittance at a wavelength of 254 nm by a weather resistance test were performed. The results are shown in Table 2. In Table 2, the portion indicated as ND is not measured. Further, in each ultraviolet transmission filter, the transmittance at a wavelength of 254 nm before the ultraviolet irradiation test is different from the transmittance at a wavelength of 254 nm before the weather resistance test. This is due to variations in the thickness of the glass plate, the thickness of the protective film, and measurement errors. Particularly, it is difficult to control the film thickness of the wet coat, and the film thickness of the film containing the silica undercoat and the hollow silica particles described is a target numerical value. The UV transmission filter used for the evaluation showed such a variation in transmittance. By measuring the transmittance before the test for each sample used in each evaluation test, the transmission at a wavelength of 254 nm before and after each test was performed. The rate degradation rate can be accurately evaluated.

  For each glass plate, as described later, a protective film was formed to form an ultraviolet transmission filter, and each measurement and evaluation of the degree of deterioration of transmittance at a wavelength of 254 nm by a weather resistance test (500 hours) were performed. These results are shown in Table 3.

(Example 11)
[Manufacture of UV transmission filter]
A single-layer film made of silicon oxide (SiO ₂ ) having a film thickness of 30 nm was formed on the main surface of the glass plate (glass A) obtained above by a sputtering method to produce an ultraviolet transmission filter. The protective film was formed on both main surfaces of the glass plate.

(Degree of deterioration of transmittance by weather resistance test (500 hours))
The ultraviolet transmissive filters obtained in Examples 1 and 6 to 11 and the glass plates (without a protective film) used in these ultraviolet transmissive filters were each in a high temperature and high humidity (temperature 85 ° C., relative humidity 85%) atmosphere. Hold for 500 hours. The transmittance at a wavelength of 254 nm before and after the weather resistance test was measured with the same ultraviolet-visible near-infrared spectrophotometer as described above, and the degree of deterioration was calculated by the following formula.

  Degree of transmittance deterioration by weather resistance test (%) = [(transmittance before weather resistance test−transmittance after weather resistance test) / transmittance before weather resistance test] × 100

  From Tables 1, 2, and 3, it can be seen that the ultraviolet transmission filters of the examples have a low degree of transmittance deterioration at a wavelength of 254 nm according to the weather resistance test and have excellent weather resistance. In addition, it can be seen that the ultraviolet transmission filter in which the dielectric multilayer film is formed as the protective film has a very low degree of deterioration of transmittance at a wavelength of 254 nm in the ultraviolet irradiation test, and further has excellent weather resistance.

  DESCRIPTION OF SYMBOLS 1 ... UV transmission filter, 2 ... Glass plate, 3 ... Protective film

Claims (20)

A glass plate, and a protective film provided on the main surface of the glass plate,
The glass plate is a molar percentage display based on oxide,
The SiO ₂ 55~80%,
12-27% B ₂ O ₃
4 to 20% of R ₂ O (R represents at least one alkali metal selected from the group consisting of Li, Na, and K),
Al ₂ O ₃ 0-5%
0 to 5% of R′O (R ′ represents at least one alkaline earth metal selected from the group consisting of Mg, Ca, Sr, and Ba);
ZnO 0-5%,
ZrO ₂ from 0 to 20%,
0 to 5% of Ta ₂ O ₅ is contained,
The ultraviolet transmission filter, wherein the glass plate is formed of glass having a transmittance of 70% or more at a wavelength of 254 nm in a spectral transmittance at a thickness of 0.5 mm.   The ultraviolet transmissive filter according to claim 1, wherein the protective film imparts at least one function selected from weather resistance, alkali resistance, acid resistance, and chemical resistance to the ultraviolet transmissive filter. The ultraviolet transmissive filter according to claim 1, wherein the protective film is a film mainly composed of SiO ₂ and contains hollow silica particles in the protective film. The protective film is at least one single layer selected from the group consisting of SiO ₂ , Si ₃ N ₄ , Si ₄ O ₅ N ₃ , Al ₂ O ₃ , ZrO ₂ , TiO ₂ , Ta ₂ O ₅ and MgF _2. The ultraviolet transmission filter according to claim 1, comprising a film.   The ultraviolet transmissive filter according to claim 1, wherein the protective film is made of a dielectric multilayer film.   The dielectric multilayer film is formed by alternately laminating a low refractive index film and a high refractive index film, and the high refractive index film includes at least one selected from hafnium oxide and tantalum oxide. Item 6. The ultraviolet transmissive filter according to Item 5.   The ultraviolet transmission filter according to any one of claims 1 to 6, wherein an average transmittance at a wavelength of 200 nm to 230 nm is 60% or less. The ultraviolet transmission filter according to claim 1, wherein the glass does not substantially contain Al ₂ O ₃ . The ultraviolet transmission filter according to claim 1, wherein the glass contains 0.5 to 5% of Al ₂ O ₃ . The ultraviolet transmission filter according to claim 1, wherein the glass contains 1.5 to 20% of ZrO ₂ . The ultraviolet transmissive filter according to claim 1, wherein the glass contains 0.01 to ₂ % of Ta ₂ O ₅ .   The glass is substantially free of R′O (R ′ represents an alkaline earth metal selected from the group consisting of Mg, Ca, Sr, and Ba). The ultraviolet transmissive filter of any one of thru | or 11. The glass _is characterized by further containing Fe ₂ O 3 0.00005~0.01% and / or _TiO 2 0.0001 to 0.02%, to any one of claims 1 to 12 The ultraviolet ray transmitting filter described. The _{glass, Cr 2 O 3, NiO,} CuO, characterized in that none of _{CeO 2, V 2 O 5,} WO 3, MoO 3, MnO 2, and CoO substantially devoid, claims 1 14. The ultraviolet transmissive filter according to any one of items 13.   The ultraviolet transmission filter according to claim 1, wherein the glass does not substantially contain Cl. The ultraviolet transmission filter according to any one of claims 1 to 15, wherein a deterioration degree of transmittance at a wavelength of 254 nm obtained by the following formula in a weather resistance test is 3% or less.
Degree of deterioration by weather resistance test (%) = [(T0−T2) / T0] × 100
(In the formula, T0 is an initial transmittance at a wavelength of 254 nm of an ultraviolet transmission filter having a protective film on one main surface of the glass plate having a thickness of 0.5 mm whose both surfaces are optically polished, and T2 is the ultraviolet ray. (The transmittance at a wavelength of 254 nm after holding the transmission filter in an atmosphere of 85 ° C. and 85% relative humidity for 500 hours.) The ultraviolet ray transmission filter according to any one of claims 1 to 16, wherein a deterioration degree of transmittance at a wavelength of 254 nm, which is obtained by the following formula in a weather resistance test, is 5% or less.
Degree of deterioration by weather resistance test (%) = [(T0−T1) / T0] × 100
(In the formula, T0 is an initial transmittance at a wavelength of 254 nm of an ultraviolet transmission filter having a protective film on one main surface of the glass plate having a thickness of 0.5 mm whose both surfaces are optically polished, and T1 is the ultraviolet ray. (The transmittance at a wavelength of 254 nm after holding the transmission filter in an atmosphere of 85 ° C. and 85% relative humidity for 1000 hours.) The ultraviolet transmission filter according to any one of claims 1 to 17, wherein, in the ultraviolet irradiation test, the degree of deterioration of transmittance at a wavelength of 254 nm, which is obtained by the following formula, is 5% or less.
Degree of deterioration by ultraviolet irradiation test (%) = [(T0−T3) / T0] × 100
(In the formula, T0 is an initial transmittance at a wavelength of 254 nm of an ultraviolet transmission filter having a protective film on one main surface of the glass plate having a thickness of 0.5 mm whose both surfaces are optically polished, and T3 is the ultraviolet ray. (Transmittance at a wavelength of 254 nm after irradiating the transmission filter with ultraviolet light having a wavelength of 254 nm with an intensity of 10 mW / cm ² from the main surface side provided with the protective film for 1000 hours.)   19. The ultraviolet transmission filter according to claim 1, wherein a transmittance at a wavelength of 254 nm is 80% or more in a spectral transmittance at a thickness of 0.5 mm of the glass plate. 20. The glass according to claim 1, wherein the glass has an average coefficient of thermal expansion of 30 × 10 ^{−7 to} 90 × 10 ⁻⁷ / ° C. in a temperature range of 0 to 300 ° C. 20. The ultraviolet ray transmitting filter described.

Images