Fluorophosphate glass, near-infrared cut-off filter, and imaging device

Abstract

The present invention relates to: a fluorophosphate glass which contains P, Cu, Mo and F and in which the content ratio of Mo < 6 + > to Cu < 2 + > (Mo < 6 + > / Cu < 2 + >) is 0.01-0.39 on a mass basis; a near-infrared cutoff filter provided with the fluorophosphate glass; and an imaging device provided with the near-infrared cutoff filter.

Description

Technical Field

[0001] The present invention relates to fluoro-phosphate glass, a near-infrared cut-off filter, and an imaging device, and particularly to a color correction filter for a solid-state imaging element used in a digital camera, a color video camera, etc., and more particularly to fluoro-phosphate glass, a near-infrared cut-off filter, and an imaging device having excellent light transmittance in the visible light region and light absorbance in the near-infrared light region. Background Art

[0002] Solid-state imaging elements such as CCDs and CMOSs used in digital cameras and the like have spectral sensitivity from the visible light region to the near-infrared light region around 1200 nm. Therefore, the solid-state imaging element itself cannot obtain good color reproducibility, and thus a near-infrared cut-off filter glass containing a specific substance that absorbs infrared rays is used to correct the visual sensitivity of the solid-state imaging element.

[0003] Regarding this near-infrared cut-off filter glass, an optical glass in which Cu is added to fluoro-phosphate glass has been developed and used to selectively absorb wavelengths in the near-infrared light region and have high weather resistance. Compositions of these glasses are disclosed in Patent Documents 1 to 3.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Laid-Open No. 1-219037

[0007] Patent Document 2: Japanese Patent Laid-Open No. 2004-83290

[0008] Patent Document 3: Japanese Patent Laid-Open No. 2004-137100 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] In recent years, the thinning and lightening of PCs and cameras have been continuously developed, and along with this, there is a demand for ultra-wide-angle lenses. When the lens is made wide-angle, the back focal length becomes short, and thus there is a demand for thinning of the near-infrared cut-off filter provided therein.

[0011] However, when the near-infrared cut-off filter is thinned, the amount of light absorbed by Cu contained in the glass 2+ decreases, and thus the absorption of light having wavelengths in the near-infrared light region becomes weak. In addition, when the amount of Cu is increased in order to increase the amount of light absorbed by Cu 2+ the content of Cu that absorbs light having wavelengths in the visible light region + increases, and thus the light transmittance in the visible light region decreases.

[0012] In addition, when the melting temperature is lowered to obtain a high light transmittance in the visible light region, there are also the following problems: generation of foreign matter of un-melted raw materials, non-uniformity of the molten liquid due to increased viscosity, and deterioration of quality.

[0013] The present invention has been completed based on such a background, and an object thereof is to provide a fluoro-phosphate glass, a near-infrared cut-off filter, and an imaging device that can maintain a high light transmittance in the visible light region while suppressing a low light transmittance in the near-infrared light region.

[0014] Means for Solving the Problem

[0015] The inventors of the present invention repeatedly conducted in-depth research and found that in a fluoro-phosphate glass containing phosphorus (P) and fluorine (F), by containing molybdenum (Mo) while containing copper (Cu) and adjusting the content ratio of Cu to Mo to a specific range, a fluoro-phosphate glass, a near-infrared cut-off filter, and an imaging device can be obtained that can maintain a high light transmittance in the visible light region while suppressing a low light transmittance in the near-infrared light region.

[0016] That is, the present invention is as described below.

[0017] (1) A fluoro-phosphate glass, wherein the fluoro-phosphate glass contains P, Cu, Mo, and F, and the content ratio of Mo 6+ and Cu 2+ (Mo 6+ / Cu 2+ ) is 0.01 to 0.39 on a mass basis.

[0018] (2) The fluoro-phosphate glass according to (1) above, wherein the content of Mo 6+ is 0.01 mass% to 4 mass%.

[0019] (3) The fluoro-phosphate glass according to (1) above, wherein the content of Cu 2+ is 1 mass% to 20 mass%.

[0020] (4) The fluoro-phosphate glass according to (1) above, wherein the fluoro-phosphate glass further contains Na.

[0021] (5) The fluoro-phosphate glass according to (4) above, wherein the content of Na + is 0.1 mass% to 25 mass%.

[0022] (6) The fluoro-phosphate glass according to (1) above, wherein, on a mass% basis, the fluoro-phosphate glass contains:

[0023] P 5+ : 30% to 70%

[0024] Al 3+ : 0% to 20%

[0025] Li + : 0% to 20%

[0026] K + : 0% to 20%

[0027] Mg 2+ : 0% to 10%

[0028] Ca 2+ : 0% to 20%

[0029] Sr 2+ : 0% to 30%

[0030] Ba 2+ : 0% to 40%

[0031] ΣR + : 0.1% to 30% (R + is one or more components selected from Li + , Na + and K + ))

[0032] ΣR 2+ : 10% to 45% (R 2+ is one or more components selected from Mg 2+ , Ca 2+ , Sr 2+ and Ba 2+ ), and

[0033] in terms of the addition ratio other than, the fluoro-phosphate glass contains 5% to 70% by mass of F - .

[0034] (7) The fluoro-phosphate glass according to (1) above, wherein, when converted to a plate thickness of 0.1 mm, the spectral transmittance of the fluoro-phosphate glass at a wavelength of 420 nm is 85% or more.

[0035] (8) The fluoro-phosphate glass according to (1) above, wherein, when converted to a plate thickness of 0.1 mm, the spectral transmittance of the fluoro-phosphate glass at a wavelength of 1200 nm is 45% or less.

[0036] (9) The fluoro-phosphate glass according to (1) above, wherein, when the average transmittance of the fluoro-phosphate glass at wavelengths of 450 nm to 500 nm is set as A and the average transmittance of the light at wavelengths of 350 nm to 400 nm is set as B when converted to a plate thickness of 0.1 mm, the average transmittance ratio A / B is 1.020 to 2.000.

[0037] (10) A near-infrared cut-off filter, wherein the near-infrared cut-off filter includes the fluoro-phosphate glass according to any one of (1) to (9) above.

[0038] (11) An imaging device, wherein the imaging device includes the near-infrared cut-off filter according to (10) above.

[0039] Effects of the Invention

[0040] According to the present invention, it is possible to provide a fluoro-phosphate glass, a near-infrared cut-off filter, and an imaging device that can maintain a high transmittance of light in the visible light region while suppressing the transmittance of light in the near-infrared light region to a low level. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a cross-sectional view of a near-infrared cut-off filter according to an embodiment of the present invention.

[0042] Figure 2 It is a cross-sectional view showing a modified example of a near-infrared cut-off filter according to an embodiment of the present invention.

[0043] Figure 3 It is a cross-sectional view schematically showing an example of an imaging device using a near-infrared cut-off filter according to an embodiment of the present invention.

[0044] Figure 4 It is a graph showing the transmittance of light with wavelengths from 200 nm to 1200 nm in Example 9 (Example) and Example 19 (Comparative Example).

[0045] Figure 5 It is a graph showing the transmittance of light with wavelengths from 350 nm to 550 nm in Example 9 (Example) and Example 19 (Comparative Example). DETAILED DESCRIPTION OF THE INVENTION

[0046] Hereinafter, modes for implementing the present invention will be described in detail. It should be noted that the present invention is not limited to the embodiments described below. The scale of the drawings is not necessarily accurate, and some features may be exaggerated or omitted.

[0047] In addition, in the specification of the present application, "α to β" representing a range means "α or more and β or less".

[0048] <Fluoro-Phosphate Glass>

[0049] The fluoro-phosphate glass according to an embodiment of the present invention (hereinafter, also referred to as the fluoro-phosphate glass of the present embodiment or simply as fluoro-phosphate glass or glass) is characterized by containing P, Cu, Mo, and F, and the content ratio of Mo 6+ and Cu 2+ (Mo 6+ / Cu 2+ is 0.01 to 0.39 based on the mass basis.

[0050] In a fluoro-phosphate glass containing P and F, by containing Mo while containing Cu and adjusting the content ratio of Cu and Mo to a specific range, it is possible to suppress the light transmittance in the near-infrared light region to be low while maintaining a high light transmittance in the visible light region. The reason is not yet determined, but the speculation is as follows.

[0051] That is, when Cu is contained in the glass in the state of Cu 2+ or Cu + , Cu 2+ is a component that absorbs light with wavelengths in the near-infrared light region, so the light transmittance in the near-infrared light region is suppressed to be low. However, Cu + is a component that absorbs light with wavelengths in the visible light region, so the light transmittance in the visible light region becomes low. Here, it is known that Mo exists in the glass in the form of Mo 6+ (hexavalent). However, when Mo and Cu are added to the fluoro-phosphate glass at the same time, Cu + in the glass releases electrons (e - ) and becomes Cu 2+ (Cu + →Cu 2+ +e - ), and Mo 6+ accepts the electrons released by Cu + and becomes Mo 5+ (pentavalent) (Mo 6+ +e - →Mo 5+ ). As a result, the proportion of the existence of Cu + (monovalent) having an absorption characteristic near 300 nm to 600 nm in wavelength decreases, and the light transmittance of light with wavelengths of 400 nm to 540 nm increases. It is considered that Mo 5+ has the characteristic of absorbing light with a wavelength of about 400 nm, and it is considered that the light transmittance of light with a wavelength of about 400 nm does not increase for this reason. In the past, fluoro-phosphate glass containing Cu and Mo was unknown, and the above content is considered to be a new insight discovered by the inventors. On the other hand, when the content of Mo increases, the influence of the absorption of light with wavelengths in the visible light region generated by Mo 5+ is enhanced, and the transmittance in the visible light region decreases. Therefore, it is considered important to adjust the content ratio of Cu and Mo to a specific range.

[0052] It should be noted that the present invention is not limitedly interpreted as the above mechanism of action.

[0053] The components of the fluoro-phosphate glass that can constitute the present embodiment and their suitable contents will be described below. In the specification of the present application, unless otherwise specified, the contents of the components and the total content are in mass%. In addition, the transmittance of the glass of the present embodiment includes the reflection characteristics of the glass surface (that is, it is not the internal transmittance of the glass).

[0054] In the fluoro-phosphate glass of the present embodiment, P is contained in the form of P 5+ .

[0055] P 5+ is the main component for forming the fluoro-phosphate glass and is an essential component for improving the near-infrared cut-off property. If the content of P 5+ is 30% or more, its effect can be fully obtained. If the content of P 5+ is 70% or less, problems such as the glass becoming unstable or the weather resistance decreasing are not likely to occur. Therefore, the content of P 5+ is preferably 30% to 70%. The content of P 5+ is more preferably 32% or more, further preferably 34% or more, still further preferably 35% or more, most preferably 36% or more. In addition, it is more preferably 60% or less, further preferably 50% or less, still further preferably 45% or less, and most preferably 43% or less.

[0056] It should be noted that, from the viewpoints of suppressing the erosion of the platinum crucible and suppressing the volatilization of the components, phosphoric acid or its salts are preferably used as the raw materials of P 5+ .

[0057] In the fluoro-phosphate glass of the present embodiment, F is contained in the form of F - .

[0058] F - is an essential component for stabilizing the glass and improving the weather resistance. In the specification of the present application, when the component elements other than F - contained in the glass are set to 100% by mass, the content of F - contained in the glass is expressed as an external addition ratio.

[0059] F - The content of is preferably 5% to 70% in terms of the external addition ratio. If the content of F - is 5% or more in terms of the external addition ratio, the effect of weather resistance can be fully obtained. When the content of F - is 70% or less in terms of the external addition ratio, problems such as a decrease in the transmittance of light in the visible light region, or a decrease in mechanical properties such as strength, hardness, and elastic modulus, or an increase in the ultraviolet transmittance are not likely to occur. F -The content is more preferably 6% or more, further preferably 8% or more, still further preferably 8.5% or more, and most preferably 10% or more in terms of the externally added ratio. Additionally, it is more preferably 60% or less, further preferably 50% or less, still further preferably 40% or less, and most preferably 25% or less in terms of the externally added ratio.

[0060] In the fluoro-phosphate glass of the present embodiment, Cu is contained in the form of Cu + or Cu 2+ , but the content in the case where all exist in the form of Cu 2+ is described in the specification of the present application.

[0061] Cu 2+ is an essential component for near-infrared cut-off. The content of Cu 2+ is preferably 1% to 20%. If the content of Cu 2+ is 1% or more, its effects and the effect of improving the light transmittance in the visible light region of the glass obtained when added simultaneously with Mo can be sufficiently obtained. Additionally, if the content of Cu 2+ is 20% or less, problems such as devitrification foreign substances generated in the glass or a decrease in the light transmittance in the visible light region are less likely to occur. The content of Cu 2+ is more preferably 2% or more, further preferably 2.5% or more, still further preferably 3% or more, and most preferably 3.5% or more. Additionally, it is more preferably 18% or less, further preferably 16% or less, still further preferably 13% or less, and most preferably 11.5% or less.

[0062] In addition, the total Cu amount is the total amount of Cu in mass% including monovalent, divalent, and other existing valences. When the glass of the present embodiment (where the content of F - is not included) is set to 100% by mass, in this glass, the content range of the total Cu amount is preferably 1% to 20% by mass. When the total Cu amount is 1% by mass or more, even when the plate thickness of the glass is reduced, the effect of near-infrared cut-off can be sufficiently obtained. Additionally, when the total Cu amount is 20% by mass or less, a decrease in the transmittance in the visible light region can be suppressed. It should be noted that the content of Cu + in mass% can be determined within the range of 0.01% to 4.0% for (Cu + / total Cu amount)×100[%.]

[0063] In the fluoro-phosphate glass of the present embodiment, Mo is contained in the form of Mo 5+ or Mo 6+ , but the present application specification describes all in the form of Mo6+ Content in the form of

[0064] Mo 6+ is an essential component for improving the light transmittance in the visible light region of the glass. The present inventors fabricated a fluoro-phosphate glass containing Cu and a fluoro-phosphate glass containing Cu and Mo, and confirmed their optical properties. As a result, the following phenomenon was confirmed: compared with the former glass, the transmittance of light with wavelengths from 400 nm to 540 nm increased significantly in the latter glass. As described above, although it is a hypothesis, it is considered that this phenomenon is based on the following reasons.

[0065] It is known that Mo exists in the glass in the form of Mo 6+ (hexavalent). However, when Mo and Cu are added simultaneously to the phosphate glass, Cu in the glass + releases electrons (e - ) and becomes Cu 2+ (Cu + →Cu 2+ +e - ), and Mo 6+ accepts the electrons released by Cu + and becomes Mo 5+ (pentavalent) (Mo 6+ +e - →Mo 5+ ). As a result, the proportion of the existence of Cu + (monovalent) having an absorption characteristic near wavelengths from 300 nm to 600 nm decreases, and the transmittance of light with wavelengths from 400 nm to 540 nm increases. It is considered that Mo 5+ has the characteristic of absorbing light with a wavelength of about 400 nm, and it is considered that the transmittance of light with a wavelength of about 400 nm does not increase for this reason.

[0066] Mo 6+ content is preferably 0.01% to 4%. If the content of Mo 6+ is 0.01% or more, the effect of improving the light transmittance in the visible light region of the glass can be obtained sufficiently. In addition, if the content of Mo 6+ is 4% or less, problems such as a decrease in near-infrared cut-off property or the generation of devitrified foreign substances in the glass are not likely to occur. The content of Mo 6+ is more preferably 0.05% or more, further preferably 0.1% or more, still further preferably 0.2% or more, most preferably 0.3% or more. In addition, it is more preferably 3.5% or less, further preferably 3% or less, still further preferably 2% or less, most preferably 1% or less.

[0067] Mo 6+ and the content ratio of Cu 2+ (Mo 6+ / Cu2+ )is 0.01 to 0.39 based on the mass basis. By Mo 6+ and Cu 2+ content ratio (Mo 6+ / Cu 2+ )is 0.01 or more, it is possible to sufficiently suppress the absorption of light with wavelengths in the visible light region caused by Cu + , and it is possible to sufficiently promote the absorption of light with wavelengths in the near-infrared light region caused by Cu 2+ . In addition, by Mo 6+ and Cu 2+ content ratio (Mo 6+ / Cu 2+ )is 0.39 or less, it is possible to suppress the decrease in transmittance in the visible light region caused by Mo 5+ . The content ratio of Mo 6+ and Cu 2 + (Mo 6+ / Cu 2+ )is more preferably 0.02 or more, further preferably 0.03 or more, still further preferably 0.05 or more, most preferably 0.1 or more. In addition, it is more preferably 0.35 or less, further preferably 0.3 or less, still further preferably 0.25 or less, most preferably 0.2 or less.

[0068] Al 3+ is a component for forming glass and is a component for improving the strength of glass, improving the weather resistance of glass, etc. When the glass contains Al 3+ , if the content of Al 3+ is 2% or more, its effects can be sufficiently obtained. If the content of Al 3+ is 20% or less, problems such as the glass becoming unstable or the near-infrared ray cut-off property decreasing are less likely to occur. The content of Al 3+ is preferably 0% to 20%. The content of Al 3+ is more preferably 2% or more, further preferably 3% or more, still further preferably 3.5% or more, most preferably 5% or more. In addition, it is more preferably 18% or less, further preferably 15% or less, still further preferably 13% or less, most preferably 10% or less.

[0069] It should be noted that as the raw material of Al 3+ , AlF 3 , Al 2 O 3 , Al(OH) 3 , etc. can be used. Among them, from the perspective of less likely to cause an increase in melting temperature, generation of unmelted matter, and F -Considering aspects such as the reduction in the input amount and the instability of the glass, it is preferable to use AlF 3 .

[0070] Li + is a component used to lower the melting temperature of the glass, lower the liquidus temperature of the glass, stabilize the glass, etc. Li + content is preferably 0% to 20%. If the Li + content is 20% or less, problems such as the glass becoming unstable or the near-infrared cut-off property decreasing are less likely to occur. The Li + content is more preferably 1% or more, further preferably 2% or more, still further preferably 4% or more, most preferably 5% or more. Additionally, it is more preferably 18% or less, further preferably 15% or less, still further preferably 12% or less, most preferably 10% or less.

[0071] In the fluoro-phosphate glass of this embodiment, Na can be contained in the form of Na + .

[0072] Na + is a component used to lower the melting temperature of the glass, lower the liquidus temperature of the glass, stabilize the glass, etc. Additionally, by the glass containing Na + , the effect of improving the light transmittance in the visible light region of the glass obtained when added simultaneously with Mo can be fully obtained. The mechanism is as follows. Around Cu + in the fluoro-phosphate glass, there are oxygen ions, and these oxygen ions carry negative charges. The electric field generated by the negative charges hinders the transfer of electrons (e - ) between the above-mentioned Cu + and Mo 6+ (Cu + →Cu 2+ +e - ) and (Mo 6+ +e - →Mo 5+ ). By the presence of Na + in the fluoro-phosphate glass, the positive charge carried by Na + neutralizes the negative charge of the oxygen ions. As a result, the transfer of electrons between the above-mentioned Cu + and Mo 5+ is promoted, and the proportion of the existence of Cu + with light absorption characteristics in the visible light region decreases, and the light transmittance in the visible light region increases.

[0073] When the glass contains Na + , the Na + content is preferably 0.1% to 25%. If the Na +If the content of Na is 25% or less, the glass is not likely to become unstable. + The content is more preferably 0.5% or more, further preferably 1% or more, still further preferably 2% or more, most preferably 3% or more. Additionally, it is more preferably 20% or less, further preferably 18% or less, still further preferably 14% or less, most preferably 10% or less.

[0074] Mo 6+ and Na + The content ratio of Mo 6+ / Na + is preferably 0.01 - 10 on a mass basis. By the content ratio of Mo 6+ and Na + (Mo 6+ / Na + ) within the above range, the effect of improving the light transmittance in the visible light region of the glass obtained when Mo 6+ and Na + are added simultaneously can be obtained more sufficiently. The content ratio of Mo 6+ and Na + (Mo 6+ / Na + ) is more preferably 0.03 or more on a mass basis, further preferably 0.05 or more, still further preferably 0.08 or more, most preferably 0.1 or more. Additionally, it is more preferably 5 or less, further preferably 3 or less, still further preferably 1.5 or less, most preferably 1 or less.

[0075] K + is a component having effects such as reducing the melting temperature of the glass and reducing the liquidus temperature of the glass. As the content of K + , it is preferably 0% - 20%. If the content of K + is 20% or less, the glass is not likely to become unstable, and thus it is preferred. The content of K + is more preferably 15% or less, further preferably 10% or less, still further preferably 5% or less, most preferably 3% or less.

[0076] R + (selected from one or more components of Li + , Na + and K + ) is a component for reducing the melting temperature of the glass, reducing the liquidus temperature of the glass, stabilizing the glass, etc. If the total content of R + , that is, the total content of Li + , Na + and K + (ΣR + ) is 0.1% or more, the effect can be obtained sufficiently. If R+ If the total amount is 30% or less, the glass is less likely to become unstable, so it is preferred. Therefore, ΣR + The content is preferably 0.1% to 30%. ΣR + The content is more preferably 1% or more, further preferably 3% or more, still further preferably 5% or more, most preferably 8% or more. Additionally, it is more preferably 28% or less, further preferably 25% or less, still further preferably 20% or less, most preferably 13% or less.

[0077] Mg 2+ is a component for reducing the melting temperature of the glass, reducing the liquidus temperature of the glass, stabilizing the glass, increasing the strength of the glass, etc. As for the content of Mg 2+ , it is preferably 0% to 10%. If the content of Mg 2+ is 10% or less, problems such as the glass becoming unstable or the near-infrared cut-off property decreasing are less likely to occur. Mg 2+ The content is more preferably 8% or less, further preferably 6% or less, still further preferably 5% or less, most preferably 3% or less.

[0078] Ca 2+ is a component for reducing the melting temperature of the glass, reducing the liquidus temperature of the glass, stabilizing the glass, increasing the strength of the glass, etc. As for the content of Ca 2+ , it is preferably 0% to 20%. If the content of Ca 2+ is 20% or less, problems such as the glass becoming unstable or the near-infrared cut-off property decreasing are less likely to occur. Ca 2+ The content is more preferably 0.1% or more, further preferably 1% or more, still further preferably 2% or more, most preferably 3% or more. Additionally, it is more preferably 18% or less, further preferably 15% or less, still further preferably 10% or less, most preferably 6% or less.

[0079] Sr 2+ is a component for reducing the melting temperature of the glass, reducing the liquidus temperature of the glass, stabilizing the glass, etc. As for the content of Sr 2+ , it is preferably 0% to 30%. If the content of Sr 2+ is 30% or less, problems such as the glass becoming unstable or the near-infrared cut-off property decreasing are less likely to occur. Sr 2+ The content is more preferably 0.1% or more, further preferably 1% or more, still further preferably 3% or more, most preferably 5% or more. Additionally, it is more preferably 25% or less, further preferably 20% or less, still further preferably 15% or less, most preferably 10% or less.

[0080] Ba 2+is a component for reducing the melting temperature of glass, reducing the liquidus temperature of glass, stabilizing the glass, etc. As Ba 2+ content, it is preferably 0% to 40%. If the Ba 2+ content is 40% or less, problems such as the glass becoming unstable or the near-infrared cut-off property decreasing are less likely to occur. The Ba 2+ content is more preferably 0.1% or more, further preferably 5% or more, still further preferably 10% or more, most preferably 15% or more. Additionally, it is more preferably 35% or less, further preferably 30% or less, still further preferably 25% or less, most preferably 23% or less.

[0081] R 2+ (selected from one or more components of Mg 2+ , Ca 2+ , Sr 2+ and Ba 2+ ) is a component for reducing the melting temperature of glass, reducing the liquidus temperature of glass, stabilizing the glass, etc. If the total amount of R 2+ , that is, the total amount of Mg 2+ , Ca 2+ , Sr 2+ and Ba 2+ (ΣR 2+ ) is 10% or more, its effect can be fully obtained. If the total amount of R 2+ is 45% or less, the glass is less likely to become unstable. Therefore, the content of ΣR 2+ is preferably 10% to 45%. The content of ΣR 2+ is more preferably 15% or more, further preferably 20% or more, still further preferably 23% or more, most preferably 25% or more. Additionally, it is more preferably 40% or less, further preferably 35% or less, still further preferably 33% or less, most preferably 30% or less.

[0082] Zn 2+ has the effects of reducing the melting temperature of glass and reducing the liquidus temperature of glass. The Zn 2+ content is preferably 0% to 30%. If the Zn 2+ content is 30% or less, problems such as the glass becoming unstable, the meltability of the glass deteriorating, or the near-infrared cut-off property decreasing are less likely to occur. The Zn 2+ content is more preferably 20% or less, further preferably 15% or less, still further preferably 10% or less, most preferably 5% or less.

[0083] Rb + is a component having the effects of reducing the melting temperature of glass and reducing the liquidus temperature of glass. As Rb +The content of is preferably 0% to 10%. If the content of Rb + is less than 10%, the glass is not likely to become unstable. The content of Rb + is more preferably less than 8%, further preferably less than 6%, still further preferably less than 4%, and most preferably less than 2%.

[0084] Cs + is a component that has effects such as reducing the melting temperature of the glass and reducing the liquidus temperature of the glass. As the content of Cs + is preferably 0% to 10%. If the content of Cs + is less than 10%, the glass is not likely to become unstable. The content of Cs + is more preferably less than 8%, further preferably less than 6%, still further preferably less than 4%, and most preferably less than 2%.

[0085] In order to stabilize the glass, B can be contained in the range of 20% or less 3+ . If the content of B 3+ is 20% or less, problems such as deterioration of the weather resistance of the glass or reduction of the near-infrared cut-off property are less likely to occur. The content of B 3+ is more preferably 15% or less, further preferably 10% or less, still further preferably 8% or less, and most preferably 5% or less.

[0086] In the fluoro-phosphate glass of the present embodiment, in order to improve the weather resistance of the glass, SiO 2 , GeO 2 , ZrO 2 , SnO 2 , TiO 2 , CeO 2 , WO 3 , Y 2 O 3 , La 2 O 3 , Gd 2 O 3 , Yb 2 O 3 , Nb 2 O 5 can be contained. If the content of these components is 10% or less, problems such as devitrification foreign matter generation in the glass or reduction of the near-infrared cut-off property are less likely to occur. The content of the above components is preferably 4% or less, more preferably 3% or less, further preferably 2% or less, and still further preferably 1% or less.

[0087] Fe 2 O 3 , Cr 2 O 3 , Bi2 O 3 、 NiO, V 2 O 5 、 MnO 2 and CoO are all components that reduce the transmittance of light in the visible light region by being present in the glass. Therefore, it is preferred that these components are substantially not contained in the glass. Here, substantially not contained in the glass means not contained except for unavoidable impurities, and means not actively adding the component. Specifically, it means that the content rate of these components is each about 100 mass ppm or less in the glass.

[0088] The thermal expansion coefficient of the fluoro-phosphate glass of the present embodiment in the range of 30 °C to 300 °C is preferably 60×10 -7 / °C to 180×10 -7 / °C, more preferably 65×10 -7 / °C to 175×10 -7 / °C, and further preferably 70×10 -7 / °C to 170×10 -7 / °C.

[0089] When the fluoro-phosphate glass of the present embodiment is used as a color correction filter (near-infrared cut-off filter glass) of a solid-state imaging device, it also functions as a cover glass for hermetically sealing the solid-state imaging device, so it may be directly bonded to the packaging material. At this time, when the difference in thermal expansion coefficient between the near-infrared cut-off filter glass and the packaging material is large, peeling and breakage may occur at the bonding part, and the airtight state cannot be maintained.

[0090] Generally, as the packaging material, considering heat resistance, materials such as glass, crystallized glass, ceramics, and alumina are used, and it is preferred to reduce the difference in thermal expansion coefficient between these packaging materials and the near-infrared cut-off filter glass. Therefore, it is preferred to adjust the thermal expansion coefficient of the glass of the present embodiment in the temperature range of 30 °C to 300 °C to the above range.

[0091] The glass of the present embodiment preferably has a spectral transmittance of 85% or more at a wavelength of 420 nm in terms of a plate thickness of 0.1 mm. Thus, a glass with a high transmittance of light in the visible light region can be obtained. The above spectral transmittance is more preferably 87% or more, further preferably 88% or more, and particularly preferably 88.3% or more. The above spectral transmittance can be measured by the method described in the examples.

[0092] The glass of this embodiment preferably has a spectral transmittance of 45% or less at a wavelength of 1200 nm when converted to a plate thickness of 0.1 mm. Thus, glass with a low transmittance of light in the near-infrared light region can be obtained. The above spectral transmittance is more preferably 40% or less, further preferably 30% or less, and particularly preferably 25% or less. The above spectral transmittance can be measured by the method described in the examples.

[0093] The glass of this embodiment preferably has an average transmittance of 88.5% or more for light with a wavelength of 450 nm to 500 nm when converted to a thickness of 0.1 mm. Thus, glass with a high transmittance of light in the visible light region can be obtained. The above average transmittance of light is preferably 88.6% or more, more preferably 88.7% or more, further preferably 88.8% or more, still more preferably 88.9% or more, and most preferably 89.0% or more. The above average transmittance can be measured by the method described in the examples.

[0094] The glass of this embodiment preferably has an average transmittance of 89% or less for light with a wavelength of 350 nm to 400 nm when converted to a thickness of 0.1 mm. Thus, glass with a low transmittance of light in the ultraviolet light region can be obtained. The above average transmittance of light is more preferably 88% or less, further preferably 86% or less, still more preferably 84% or less, and most preferably 82% or less. The above average transmittance can be measured by the method described in the examples.

[0095] The glass of this embodiment preferably has an average transmittance ratio A / B of 1.020 to 2.000 when the average transmittance of light with a wavelength of 450 nm to 500 nm when converted to a thickness of 0.1 mm is set as A and the average transmittance of light with a wavelength of 350 nm to 400 nm when converted to a thickness of 0.1 mm is set as B. By having such optical characteristics, the glass of this embodiment can cut off ultraviolet rays while maintaining a high transmittance in the visible light region, particularly blue light. When the average transmittance ratio A / B is 1.020 or more, the above effect can be obtained more sufficiently. When the average transmittance ratio A / B is 2.000 or less, the absorption of light in the ultraviolet light region is not easily extended to the visible light region, and the transmittance of light in the visible light region is not easily reduced. The average transmittance ratio A / B of the glass of this embodiment is more preferably 1.030 to 1.800, further preferably 1.050 to 1.600, still more preferably 1.060 to 1.400, and most preferably 1.080 to 1.300.

[0096] The glass of the present embodiment, for example, when used as a color correction filter for a solid-state imaging device, is often used with a thickness of usually 2 mm or less. From the viewpoint of reducing the weight of components, it is preferably 1 mm or less, more preferably 0.5 mm or less, further preferably 0.3 mm or less, and even more preferably 0.2 mm or less. In addition, from the viewpoint of ensuring the strength of the glass, it is preferably 0.05 mm or more.

[0097] The glass of the present embodiment can be produced, for example, as follows.

[0098] First, raw materials are weighed and mixed so as to fall within the above composition range (mixing step). The raw material mixture is placed in a platinum crucible and heated and melted at a temperature of 750°C to 1000°C in an electric furnace (melting step). After sufficient stirring and clarification, it is cast into a mold and cut and polished to form a flat plate with a specified plate thickness (forming step).

[0099] In the melting step of the above manufacturing method, it is preferable to adjust the maximum temperature of the glass during melting to 1000°C or less. If the maximum temperature of the glass during melting exceeds the above temperature, the transmittance characteristics may deteriorate. The above temperature is more preferably 970°C or less, further preferably 950°C or less, and even more preferably 900°C or less.

[0100] In addition, when the temperature in the above melting step is too low, problems such as devitrification during melting and time-consuming for complete melting may occur. Therefore, it is preferably 800°C or more, more preferably 850°C or more.

[0101] The fluoro-phosphate glass of the present embodiment can have an optical multilayer film provided on at least one surface of the glass after being formed into a specified shape. Examples of the optical multilayer film include: an IR cut-off film (a film that reflects near-infrared light), a UV / IR cut-off film (a film that reflects ultraviolet and near-infrared light), a UV cut-off film (a film that reflects ultraviolet light), an antireflection film, etc. These optical thin films can be formed by known methods such as evaporation and sputtering.

[0102] An adhesion-enhancing film can be provided between the fluoro-phosphate glass of the present embodiment and the above optical multilayer film. By providing the adhesion-enhancing film, the adhesion between the glass and the optical multilayer film is improved, and film peeling can be suppressed. Examples of the adhesion-enhancing film include: silicon oxide (SiO 2 ), titanium oxide (TiO 2 ), lanthanum titanate (La 2 Ti 2 O 7 ), aluminum oxide (Al 2 O 3 ), a mixture of aluminum oxide and zirconium oxide (ZrO 2 ), magnesium fluoride (MgF2 ), calcium fluoride (CaF 2 ), strontium fluoride (SrF 2 ), fluorinated organosilicon, etc. If it is a substance containing fluorine or oxygen, the adhesiveness is higher. In particular, the adhesiveness of magnesium fluoride and / or titanium oxide to glass and the film becomes high, so it is preferably used as an adhesion-enhancing film. The adhesion-enhancing film can be a single layer or two or more layers. In the case of two or more layers, multiple substances can be combined.

[0103] <Near-infrared cut-off filter>

[0104] The near-infrared cut-off filter of the present embodiment includes the fluoro-phosphate glass of the present embodiment described above. Thus, a near-infrared cut-off filter can be obtained that can keep the transmittance of light in the visible light region (especially blue light) high while suppressing the transmittance of light in the near-infrared light region low. The near-infrared cut-off filter of the present embodiment may further include the following configuration in addition to the glass of the present embodiment.

[0105] As Figure 1 shown, the near-infrared cut-off filter 10 of the present embodiment may include: the fluoro-phosphate glass 11 of the present embodiment; an infrared light reflecting film 12 formed on one main surface of the fluoro-phosphate glass 11 and including a dielectric multilayer film that allows light in the visible light wavelength region to pass through but reflects light in the infrared light wavelength region; and an antireflection film 13 formed on the other main surface of the fluoro-phosphate glass 11.

[0106] The infrared light reflecting film 12 has the effect of imparting or enhancing the function of the near-infrared cut-off filter. The infrared light reflecting film 12 is composed of a dielectric multilayer film obtained by alternately laminating a low-refractive-index dielectric layer and a high-refractive-index dielectric layer by a sputtering method or a vacuum evaporation method, etc.

[0107] As the material of the low-refractive-index dielectric layer, for example, a material having a refractive index of 1.6 or less, preferably 1.2 to 1.6 is used. Specifically, silicon dioxide (SiO 2 ), aluminum oxide, lanthanum fluoride, magnesium fluoride, sodium hexafluoroaluminate, etc. are used. As the material of the high-refractive-index dielectric layer, for example, a material having a refractive index of 1.7 or more, preferably 1.7 to 2.5 is used. Specifically, titanium dioxide (TiO 2 ), zirconium oxide, tantalum pentoxide, niobium pentoxide, lanthanum oxide, yttrium oxide, zinc oxide, zinc sulfide, etc. are used. The refractive index is the refractive index of light with a wavelength of 550 nm.

[0108] In addition to being formed by the aforementioned sputtering method and vacuum evaporation method, the dielectric multilayer film can also be formed by an ion beam method, an ion plating method, a CVD method, etc. The sputtering method and the ion plating method are so-called plasma atmosphere treatments, and thus the adhesion to the fluoro-phosphate glass 11 can be improved.

[0109] The antireflection film 13 has the function of improving the transmittance by preventing the reflection of light incident on the near-infrared cut-off filter 10 and efficiently utilizing the incident light, and can be formed by conventionally known materials and methods. Specifically, the antireflection film 13 is composed of one or more layers of films such as silicon dioxide, titanium dioxide, tantalum pentoxide, magnesium fluoride, zirconium oxide, and aluminum oxide formed by a sputtering method, a vacuum evaporation method, an ion beam method, an ion plating method, a CVD method, etc.; or is composed of silicate esters, silicone-based materials, fluorinated methacrylate-based materials, etc. formed by a sol-gel method, a coating method, etc. The thickness of the antireflection film 13 is usually in the range of 100 nm to 600 nm.

[0110] In the near-infrared cut-off filter of the present embodiment, a second infrared light reflection film can be provided on the main surface of the fluoro-phosphate glass 11 opposite to the main surface on which the infrared light reflection film 12 is formed to replace the antireflection film 13, or a second infrared light reflection film can be provided between the antireflection film 13 and the fluoro-phosphate glass 11. The second infrared light reflection film includes a dielectric multilayer film that reflects light in the infrared light wavelength region. In addition, a second antireflection film can be provided to replace the infrared light reflection film 12, or a second antireflection film can be provided on the infrared light reflection film 12.

[0111] The near-infrared cut-off filter of the present embodiment can have an absorption layer on at least one main surface of the fluoro-phosphate glass of the present embodiment, and the absorption layer includes a near-infrared absorbing material having a maximum absorption wavelength in the near-infrared light region. By adopting such a structure, a near-infrared cut-off filter capable of suppressing the transmittance of light in the near-infrared light region to a lower level can be obtained.

[0112] When the near-infrared cut-off filter of the present embodiment has the above-mentioned infrared light reflection film and antireflection film, as Figure 2 shown, the near-infrared cut-off filter 100 can have the above-mentioned absorption layer 15 provided between the fluoro-phosphate glass 11 and the antireflection film 13. The absorption layer 15 can also be provided between the fluoro-phosphate glass 11 and the infrared light reflection film 12.

[0113] In the near-infrared cut-off filter of the present embodiment, it is preferable to add a near-infrared absorbing pigment to a transparent resin selected from acrylic resins, epoxy resins, ene-thiol resins, polycarbonate resins, polyether resins, polyarylate resins, polysulfone resins, polyethersulfone resins, polyphenylene resins, polyaryletherphosphine oxide resins, polyimide resins, polyamideimide resins, polyolefin resins, cyclic olefin resins, and polyester resins, and containing them singly or in a mixture of two or more kinds, and include it in the absorption layer.

[0114] In addition, as the near-infrared absorbing pigment, it is preferable to use a near-infrared absorbing material containing at least one pigment selected from the group consisting of squarylium salts pigments, phthalocyanine pigments, cyanine pigments, and diiminium pigments.

[0115] <Imaging device>

[0116] The imaging device of the embodiment of the present invention preferably includes the near-infrared cut-off filter of the above-described embodiment of the present invention. In addition, the imaging device of the present embodiment preferably includes a solid-state imaging element and an imaging lens in addition to the near-infrared cut-off filter of the above-described embodiment. The near-infrared cut-off filter of the present embodiment can be disposed, for example, between the above-described imaging lens and the solid-state imaging element, or directly adhered to the solid-state imaging element, imaging lens, etc. of the imaging device via an adhesive layer for use. By including a near-infrared cut-off filter having excellent visible light transmittance, specific near-infrared light shielding property, and not easily shifting spectral curves even at a high incident angle, an imaging device with excellent color reproducibility even for light at a high incident angle can be obtained.

[0117] When the near-infrared cut-off filter is installed in the imaging device, in the case where the near-infrared cut-off filter has the above-described infrared light reflection film and antireflection film, it is generally preferable to install the near-infrared cut-off filter in the imaging device such that the infrared light reflection film faces the above-described imaging lens side (external light incident side) and the antireflection film faces the solid-state imaging element (sensor) side.

[0118] For example, as Figure 3 shown, the imaging device 50 of the present embodiment may include a solid-state imaging element 51, a near-infrared cut-off filter 52, an imaging lens 53, and a housing 54 that holds and fixes them.

[0119] As described above, the following matters are disclosed in the present application specification.

[0120] (1) A fluoro-phosphate glass, wherein the fluoro-phosphate glass contains P, Cu, Mo, and F, and the content ratio of Mo 6+ and Cu 2+ (Mo 6+ / Cu2+ is 0.01 to 0.39 based on the mass basis.

[0121] (2) The fluoro-phosphate glass according to (1) above, wherein the content of Mo 6+ is 0.01% by mass to 4% by mass.

[0122] (3) The fluoro-phosphate glass according to (1) or (2) above, wherein the content of Cu 2+ is 1% by mass to 20% by mass.

[0123] (4) The fluoro-phosphate glass according to any one of (1) to (3) above, wherein the fluoro-phosphate glass further contains Na.

[0124] (5) The fluoro-phosphate glass according to (4) above, wherein the content of Na + is 0.1% by mass to 25% by mass.

[0125] (6) The fluoro-phosphate glass according to any one of (1) to (5) above, wherein, by mass%, the fluoro-phosphate glass contains:

[0126] P 5+ : 30% - 70%

[0127] Al 3+ : 0% - 20%

[0128] Li + : 0% - 20%

[0129] K + : 0% - 20%

[0130] Mg 2+ : 0% - 10%

[0131] Ca 2+ : 0% - 20%

[0132] Sr 2+ : 0% - 30%

[0133] Ba 2+ : 0% - 40%

[0134] ΣR + : 0.1% - 30% (R + is one or more components selected from Li + , Na + and K + )

[0135] ΣR 2+ : 10% - 45% (R 2+ is one or more components selected from Mg 2+, Ca 2+ , Sr 2+ and Ba 2+ (one or more components among them), and

[0136] In terms of the addition ratio other than this, the fluoro-phosphate glass contains 5% to 70% by mass of F - .

[0137] (7) The fluoro-phosphate glass according to any one of (1) to (6) above, wherein, when converted to a plate thickness of 0.1 mm, the spectral transmittance of the fluoro-phosphate glass at a wavelength of 420 nm is 85% or more.

[0138] (8) The fluoro-phosphate glass according to any one of (1) to (7) above, wherein, when converted to a plate thickness of 0.1 mm, the spectral transmittance of the fluoro-phosphate glass at a wavelength of 1200 nm is 45% or less.

[0139] (9) The fluoro-phosphate glass according to any one of (1) to (8) above, wherein, when the average transmittance of the fluoro-phosphate glass at wavelengths of 450 nm to 500 nm is set as A and the average transmittance of the fluoro-phosphate glass at wavelengths of 350 nm to 400 nm is set as B when converted to a plate thickness of 0.1 mm, the average transmittance ratio A / B is 1.020 to 2.000.

[0140] (10) A near-infrared cut-off filter, wherein the near-infrared cut-off filter includes the fluoro-phosphate glass according to any one of (1) to (9) above.

[0141] (11) An imaging device, wherein the imaging device includes the near-infrared cut-off filter according to (10) above.

[0142] Examples

[0143] Hereinafter, examples will be described, but the present invention is not limited to these examples.

[0144] Examples and comparative examples of the fluoro-phosphate glass of the present invention are shown in Tables 1 and 2. Examples 1 to 14 are examples, and Examples 15 to 20 are comparative examples.

[0145] [Fabrication of glass]

[0146] Regarding the glass of Examples 1 to 20, the raw materials were weighed and mixed so that the composition (mass %) of the molten glass became the composition shown in Tables 1 and 2. The mixture was put into a platinum crucible with an internal volume of 1 L and heated and melted in an electric furnace at the melting temperature recorded in each table for 2 hours. Then, it was clarified, stirred, and cast into a rectangular mold preheated to 50°C to 500°C with a length of 100 mm, a width of 80 mm, and a height of 20 mm. After being held at 300°C to 500°C, it was slowly cooled at about 1°C / minute to obtain a glass sample in the form of a plate-like body with a length of 40 mm, a width of 40 mm, and a plate thickness of 0.1 mm to 0.3 mm, with both sides optically polished.

[0147] It should be noted that F - is the external addition ratio.

[0148] As the raw materials for each glass, the following raw materials were used.

[0149] In the case of P 5+ , H 3 PO 4 was used.

[0150] In the case of Al 3+ , AlF 3 was used.

[0151] In the case of Li + , LiF and LiNO 3 were used.

[0152] In the case of Na + , NaF was used.

[0153] In the case of K + , KF was used.

[0154] In the case of Mg 2+ , MgO was used.

[0155] In the case of Ca 2+ , CaF 2 was used.

[0156] In the case of Sr 2+ , SrF 2 was used.

[0157] In the case of Ba 2+ , BaF 2 was used.

[0158] In the case of Cu 2+ , CuO was used.

[0159] In the case of Mo 6+ , MoO3 .

[0160] In the case of F - fluoride raw materials of the above components are used.

[0161] In addition to the components described in the examples and comparative examples, as anions, O 2- .O 2- The content of O varies according to the content of F with high volatility, so it is not described, but all the glasses in the examples and comparative examples contain O - . 2- .

[0162] It should be noted that the raw materials of the glass are not limited to the above raw materials, and known raw materials can be used.

[0163] [Evaluation]

[0164] The transmittance of the glass of the sample produced in the above manner was measured. Regarding the transmittance, the transmittance of light with a wavelength of 200 nm to 1200 nm was measured every 1 nm using a spectrophotometer (manufactured by JASCO Corporation, V-570), and conversion was performed in such a way that the value became a plate thickness of 0.1 mm. Regarding the conversion, the obtained transmittance was first converted into the internal transmittance and the conversion was performed using the following formula.

[0165] T i2 =T i1 (t2 / t1)

[0166] ·T i1 : Internal transmittance of the actual sample (before conversion)

[0167] ·t1: Plate thickness of the actual sample

[0168] ·T i2 : Internal transmittance after conversion

[0169] ·t2: Plate thickness to be converted

[0170] Based on the transmittance that includes the reflection losses of the front and back surfaces of the internal transmittance (T i2 ), the spectral transmittance at a wavelength of 1200 nm, the spectral transmittance at a wavelength of 420 nm, the average transmittance A of light with a wavelength of 450 nm to 500 nm, and the average transmittance B of light with a wavelength of 350 nm to 400 nm were obtained. In addition, the average transmittance ratio A / B was calculated based on the above average transmittance A and average transmittance B.

[0171] The results are shown in Tables 1 and 2.

[0172] In addition, the transmittances of light with wavelengths from 200 nm to 1200 nm in Example 9 (Example) and Example 19 (Comparative Example) are shown in Figure 4 .

[0173] In addition, the transmittances of light with wavelengths from 350 nm to 550 nm in Example 9 (Example) and Example 19 (Comparative Example) are shown in Figure 5 .

[0174] [Table 1]

[0175]

[0176] [Table 2]

[0177]

[0178] Examples 1 to 3 as examples were added with Mo 6+ / Cu 2+ in the range of 0.01 to 0.39 compared with Example 15 as a comparative example. Therefore, the spectral transmittance at 420 nm of Examples 1 to 3 is higher than that of Example 15. On the other hand, Example 16 as a comparative example was added with Mo 6+ / Cu 2+ in a manner greater than 0.39 compared with Example 15 as a comparative example. Therefore, the spectral transmittance at 420 nm of Example 16 is worse than that of Example 15.

[0179] Examples 4 to 7 as examples were added with Mo 6+ / Cu 2+ in the range of 0.01 to 0.39 compared with Example 17 as a comparative example. Therefore, the spectral transmittance at 420 nm of Examples 4 to 7 is higher than that of Example 17. In addition, Examples 4 to 7 as examples can suppress the spectral transmittance at 1200 nm to a low level. On the other hand, Example 18 as a comparative example was added with Mo 6+ / Cu 2+ in a manner greater than 0.39 compared with Example 17 as a comparative example. Therefore, the spectral transmittance at 420 nm of Example 18 is worse than that of Example 17.

[0180] Examples 8 and 9 as examples were added with Mo 6+ / Cu 2+ in the range of 0.01 to 0.39 compared with Example 19 as a comparative example. Therefore, the spectral transmittance at 420 nm of Examples 8 and 9 is higher than that of Example 19.

[0181] Examples 10 and 11 as examples were added with Mo 6+ / Cu 2+Mo was added in a manner within the range of 0.01 to 0.39. Therefore, compared with Example 20, the spectral transmittance at 420 nm in Example 10 and Example 11 was improved.

[0182] In Examples 12 to 14 as examples, Mo 6+ / Cu 2+ Within the range of 0.01 to 0.39, it is possible to suppress the spectral transmittance at a wavelength of 1200 nm to be low while maintaining a high spectral transmittance at 420 nm.

[0183] As described above, various embodiments have been described with reference to the drawings. Needless to say, the present invention is not limited to the above examples. Obviously, those skilled in the art can conceive of various modification examples or correction examples within the scope described in the claims, and these of course also belong to the technical scope of the present invention. In addition, within the scope not departing from the gist of the invention, the constituent elements in the above embodiments can be arbitrarily combined.

[0184] It should be noted that this application is based on a Japanese patent application filed on November 18, 2022 (Japanese Patent Application No. 2022-185114), the content of which is incorporated herein by reference.

[0185] Reference Numeral Explanation

[0186] 10, 100 Near-infrared Cutoff Filter

[0187] 11 Fluorophosphate Glass

[0188] 12 Infrared Light Reflective Film

[0189] 13 Anti-reflection Film

[0190] 15 Absorbing Layer

[0191] 50 Imaging Device

[0192] 51 Solid-state Imaging Element

[0193] 52 Near-infrared Cutoff Filter

[0194] 53 Imaging Lens

[0195] 54 Housing

Claims

1. A fluoro-phosphate glass, wherein, The fluorophosphate glass contains P, Cu, Mo and F, and Mo 6+ and Cu 2+ The content ratio (Mo 6+ / Cu 2+ ) is 0.01 to 0.39 based on mass.

2. The fluoro-phosphate glass according to claim 1, wherein, Mo 6+ The content is 0.01% by mass to 4% by mass.

3. The fluoro-phosphate glass according to claim 1, wherein, Cu 2+ The content thereof is 1% to 20% by mass.

4. The fluoro-phosphate glass according to claim 1, wherein, the fluoro-phosphate glass further contains Na.

5. The fluoro-phosphate glass according to claim 4, wherein, The content of Na + is 0.1% by mass to 25% by mass.

6. The fluoro-phosphate glass according to claim 1, wherein, in terms of mass%, the fluoro-phosphate glass contains: P 5+ ：30%～70% Al 3+ ：0%～20% Li + : 0% to 20% K + ：0%～20% Mg 2+ : 0% to 10% Ca 2+ : 0% to 20% Sr 2+ ：0%～30% Ba 2+ : 0% to 40% ΣR + : 0.1% to 30% (R + is selected from Li + , Na + and K + and one or more components) ΣR 2+ : 10% to 45% (R 2+ is selected from Mg 2+ , Ca 2+ , Sr 2+ and Ba 2+ among more than one component), and Based on the externally added ratio, the fluoro-phosphate glass contains 5% to 70% by mass of F - .

7. The fluoro-phosphate glass according to claim 1, wherein, when converted to a plate thickness of 0.1 mm, the spectral transmittance of the fluoro-phosphate glass at a wavelength of 420 nm is 85% or more.

8. The fluoro-phosphate glass according to claim 1, wherein, when converted to a plate thickness of 0.1 mm, the spectral transmittance of the fluoro-phosphate glass at a wavelength of 1200 nm is 45% or less.

9. The fluoro-phosphate glass according to claim 1, wherein, when the average transmittance of the light with wavelengths of 450 nm to 500 nm of the fluoro-phosphate glass converted to a plate thickness of 0.1 mm is set as A, and the average transmittance of the light with wavelengths of 350 nm to 400 nm is set as B, the average transmittance ratio A / B is 1.020 to 2.

000.

10. A near-infrared cut-off filter, wherein, the near-infrared cut-off filter includes the fluoro-phosphate glass according to any one of claims 1 to 9.

11. An imaging device, wherein, the imaging device includes the near-infrared cut-off filter according to claim 10.

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