Optical filter

Abstract

The present invention aims to provide an optical filter that has excellent weather resistance, excellent transmittance in the visible light region, excellent shielding in the near-infrared light region, particularly over a wide range including around 1200 nm, and exhibits minimal change in spectral characteristics even at high incidence angles. [Solution] The present invention relates to an optical filter comprising, in this order, a dielectric multilayer film 1, a substrate having a near-infrared absorbing glass and a resin film, and a dielectric multilayer film 2, wherein the resin film contains a near-infrared absorbing dye and a resin, the near-infrared absorbing glass is phthalic acid glass containing P, Cu, and F, and the optical filter satisfies all of the specific spectral characteristics (i-1) to (i-3) and (i-5), and (i-6) or (i-7).

Description

[Technical Field]

[0001] This invention relates to an optical filter that transmits visible light and blocks near-infrared light. [Background technology]

[0002] In imaging devices using solid-state image sensors, optical filters are used that transmit visible light (hereinafter also referred to as "visible light") and block near-infrared wavelength light (hereinafter also referred to as "near-infrared light") in order to reproduce colors well and obtain sharp images.

[0003] Examples of such optical filters include reflective filters that alternately layer dielectric thin films with different refractive indices on one or both sides of a transparent substrate (dielectric multilayer film) and reflect light to be blocked by utilizing light interference; absorbing filters that absorb light to be blocked using glass or dyes that absorb light in a specific wavelength range; and filters that combine reflective and absorbing types.

[0004] Patent Document 1 describes an optical filter containing a copper complex that absorbs light in the near-infrared region. Patent document 2 describes an optical filter containing a dye that absorbs light in the near-infrared region. Patent Document 3 describes an optical filter comprising a glass that absorbs light in the near-infrared region and a reflective layer made of a dielectric multilayer film. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent No. 6802938 [Patent Document 2] International Publication No. 2019 / 168090 [Patent Document 3] International Publication No. 2019 / 151348 [Overview of the project] [Problems that the invention aims to solve]

[0006] The optical filter described in Patent Document 1 has a copper complex that absorbs light coated onto phosphate glass, and it has poor moisture resistance and room for improvement in terms of weather resistance.

[0007] The optical filter described in Patent Document 2 has room for improvement in that it blocks light over a wide area in the near-infrared region solely by the absorption characteristics of the dye, which reduces the transmittance in the visible light region.

[0008] Furthermore, optical filters that utilize the reflection of a dielectric multilayer film, such as the optical filter described in Patent Document 3, raise concerns about changes in the spectral transmittance curve and spectral reflectance curve depending on the angle of incidence, because the optical thickness of the dielectric multilayer film changes depending on the angle of incidence. For example, if the amount of light captured in the visible light region changes at high angles of incidence, a problem arises in which image reproducibility deteriorates. In particular, with the recent trend towards lower-profile camera modules, use under high angle of incidence conditions is anticipated, so there is a need for optical filters that are less affected by the angle of incidence.

[0009] The present invention aims to provide an optical filter that has excellent weather resistance, excellent transmittance in the visible light region, excellent shielding in the near-infrared light region, particularly over a wide range including around 1200 nm, and exhibits minimal change in spectral characteristics even at high incidence angles. [Means for solving the problem]

[0010] The present invention provides an optical filter and the like having the following configuration. [1] An optical filter comprising, in this order, a dielectric multilayer film 1, a substrate having near-infrared absorbing glass and a resin film, and a dielectric multilayer film 2, The aforementioned resin film contains a near-infrared absorbing dye and a resin, The near-infrared absorbing glass is a phthalic acid glass containing P, Cu, and F. The optical filter is an optical filter that satisfies all of the following spectral characteristics (i-1) to (i-3), (i-5), and (i-6). (i-1) The average transmittance T at a wavelength of 440 to 600 nm and an incident angle of 0 degrees 440-600(60deg)AVE , , , 850-1200(5deg)AVE , 50(0deg) , , 440-600(0deg)AVE , , , , 800-1200(0deg)AVE and the average transmittance T at a wavelength of 440 to 600 nm and an incident angle of 60 degrees 440-600(60deg)AVE The absolute value of the difference therebetween is 15% or less (i-2) The average transmittance T 440-600(0deg)AVE is 75% or more (i-3) The wavelength IR_T at which the transmittance becomes 50% at an incident angle of 0 degrees 50(0deg) is in the wavelength range of 580 to 640 nm (i-5) The average transmittance T at a wavelength of 800 to 1200 nm and an incident angle of 0 degrees 800-1200(0deg)AVE is 5% or less (i-6) When the dielectric multilayer film 1 side is the incident direction, the average reflectance R1 at a wavelength of 440 to 650 nm and an incident angle of 5 degrees 440-650(5deg)AVE is 1.5% or less [2] An optical filter comprising a dielectric multilayer film 1, a substrate having a near-infrared absorbing glass and a resin film, and a dielectric multilayer film 2 in this order, The resin film contains a near-infrared absorbing dye and a resin, The near-infrared absorbing glass is a fluorophosphate glass containing P, Cu, and F, The optical filter is an optical filter that satisfies all of the following spectral characteristics (i-1) to (i-3), (i-5), and (i-7). (i-1) The average transmittance T at a wavelength of 440 to 600 nm and an incident angle of 0 degrees 440-600(0deg)AVE and the average transmittance T at a wavelength of 440 to 600 nm and an incident angle of 60 degrees 440-600(60deg)AVE The absolute value of the difference therebetween is 15% or less (i-2) The average transmittance T 440-600(0deg)AVE is 75% or more (i-3) The wavelength IR_T at which the transmittance becomes 50% at an incident angle of 0 degrees 50(0deg) is in the wavelength range of 580 to 640 nm (i-5) The average transmittance T at a wavelength of 800 to 1200 nm and an incident angle of 0 degrees 800-1200(0deg)AVE is 5% or less (i-7) When the dielectric multilayer film 1 side is the incident direction, the average reflectance R1 at a wavelength of 850 to 1200 nm and an incident angle of 5 degrees 850-1200(5deg)AVE is 60% or more [Advantages of the Invention]

[0011] According to the present invention, it is possible to provide an optical filter that has excellent weather resistance, excellent transmittance in the visible light region, excellent shielding in the near-infrared light region, particularly over a wide range including around 1200 nm, and exhibits little change in spectral characteristics even at high incidence angles. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a schematic cross-sectional view showing an example of an optical filter according to one embodiment. [Figure 2] Figure 2 shows the spectral transmittance curve (0-degree transmittance, 60-degree transmittance) of the optical filter in Example 1. [Figure 3] Figure 3 shows the spectral reflectance curve (5-degree reflectance, 60-degree reflectance, dielectric multilayer film 1 side) of the optical filter in Example 1. [Figure 4] Figure 4 shows the spectral reflectance curve (5-degree reflectance, 60-degree reflectance, dielectric multilayer film 2 side) of the optical filter in Example 1. [Figure 5] Figure 5 shows the spectral transmittance curve (0-degree transmittance, 60-degree transmittance) of the optical filter in Example 2. [Figure 6] Figure 6 shows the spectral reflectance curve (5-degree reflectance, 60-degree reflectance, dielectric multilayer film 1 side) of the optical filter in Example 2. [Figure 7] Figure 7 shows the spectral transmittance curve (0-degree transmittance, 60-degree transmittance) of the optical filter in Example 3. [Figure 8] Figure 8 shows the spectral transmittance curve (0-degree transmittance, 60-degree transmittance) of the optical filter in Example 4. [Figure 9] Figure 9 shows the spectral transmittance curve (0-degree transmittance, 60-degree transmittance) of the optical filter in Example 5. [Figure 10] Figure 10 shows the spectral transmittance curve (0-degree transmittance, 60-degree transmittance) of the optical filter in Example 6. [Modes for carrying out the invention]

[0013] Embodiments of the present invention will be described below. In this specification, near-infrared absorbing dyes may be abbreviated as "NIR dyes," and ultraviolet absorbing dyes may be abbreviated as "UV dyes." In this specification, the compound represented by formula (I) is referred to as compound (I). The same applies to compounds represented by other formulas. A dye consisting of compound (I) is also referred to as dye (I), and the same applies to other dyes. Furthermore, the group represented by formula (I) is also referred to as group (I), and the same applies to groups represented by other formulas.

[0014] In this specification, internal transmittance is defined by the formula {measured transmittance (incident angle 0 degrees) / (100 - reflectance (incident angle 5 degrees))} × 100, which is the transmittance obtained by subtracting the effect of interfacial reflection from the measured transmittance.

[0015] In this specification, for a specific wavelength range, a transmittance of, for example, 90% or more means that the transmittance does not fall below 90% across the entire wavelength range, i.e., the minimum transmittance in that wavelength range is 90% or more. Similarly, for a specific wavelength range, a transmittance of, for example, 1% or less means that the transmittance does not exceed 1% across the entire wavelength range, i.e., the maximum transmittance in that wavelength range is 1% or less. The same applies to internal transmittance. The average transmittance and average internal transmittance in a specific wavelength range are the arithmetic mean of the transmittance and internal transmittance for every 1 nm in that wavelength range. Reflectance with the dielectric multilayer film side as the incident direction refers to the optical properties of the reflected light when measurement light is incident toward the surface of the dielectric multilayer film provided on the optical filter. The spectral characteristics can be measured using a UV-Vis spectrophotometer. In this specification, the symbol "~" used to indicate a numerical range includes both upper and lower limits.

[0016] <Optical filters> The optical filter according to this embodiment comprises, in this order, a dielectric multilayer film 1, a substrate having a near-infrared absorbing glass and a resin film, and a dielectric multilayer film 2. The resin film contains a near-infrared absorbing dye and a resin, and the near-infrared absorbing glass is phthalic acid glass containing P, Cu, and F. In the present invention, as described later, it is preferable that the light-shielding properties of the optical filter are ensured by the absorption characteristics of the near-infrared absorbing glass and near-infrared absorbing dye, and the reflection characteristics of the dielectric multilayer film. Since the absorption characteristics are relatively unaffected by the angle of incidence of light, an optical filter with small changes in spectral characteristics can be obtained even at high angles of incidence.

[0017] An example of the configuration of an optical filter according to this embodiment will be described using the drawings. Figure 1 is a schematic cross-sectional view showing an example of an optical filter according to one embodiment.

[0018] The optical filter 1B shown in Figure 1 is an example comprising a dielectric multilayer film 21, a substrate 40 having near-infrared absorbing glass 10 and a resin film 30, and a dielectric multilayer film 22.

[0019] The optical filter according to this embodiment satisfies all of the following spectral characteristics (i-1) to (i-5). (i-1) Average transmittance T at wavelengths of 440-600 nm and incident angle of 0 degrees 440-600(0deg)AVE And the average transmittance T at a wavelength of 440-600 nm and an incident angle of 60 degrees. 440-600(60deg)AVE The absolute value of the difference is 15% or less. (i-2) The average transmittance T 440-600(0deg)AVE over 75% (i-3) Wavelength IR_T at which transmittance is 50% at an incident angle of 0 degrees 50(0deg) It is in the wavelength range of 580-640 nm. (i-4) Average transmittance T at wavelengths of 700-800 nm and an incident angle of 0 degrees 700-800(0deg)AVE less than 1.1% (i-5) Average transmittance T at wavelengths of 800-1200 nm and incident angle of 0 degrees 800-1200(0deg)AVE less than 5%

[0020] The optical filter according to this embodiment, which satisfies all of the spectral characteristics (i-1) to (i-5), has high transmittance of visible light as shown in characteristic (i-2) and high near-infrared light shielding over a wide range of 800 to 1200 nm as shown in characteristics (i-4) and (i-5). Furthermore, as shown in characteristic (i-3), there is a wavelength within a specific wavelength range where the transmittance is 50% at an incident angle of 0 degrees, and as shown in characteristic (i-1), the change in spectral characteristics of visible light is small even at high incident angles.

[0021] Satisfying spectral characteristics (i-1) and (i-2) means that the visible light transmittance does not decrease even at high incidence angles, and that the visible light transmittance is excellent. The absolute value of the difference in the spectral characteristics (i-1) is preferably 15% or less, more preferably 10% or less. Average transmittance T 440-600(0deg)AVE The percentage is preferably 76% or more, and more preferably 77% or more. The spectral characteristics (i-1) and (i-2) can be achieved, for example, by using a dielectric multilayer film with low reflectivity in the visible light region, and by using a near-infrared absorbing dye and phthalic acid glass as near-infrared absorbing glass with high transmittance in the visible light region.

[0022] Satisfying the spectral characteristics (i-3) means that the near-infrared region can be blocked and visible transmitted light can be efficiently captured. Wavelength IR_T 50(0deg) The wavelength is preferably 580-630 nm, more preferably 590-625 nm. The spectral characteristics (i-3) can be achieved, for example, by using phthalic acid glass, which will be described later, as the near-infrared absorbing glass.

[0023] Satisfying the spectral characteristics (i-4) means that the material has excellent near-infrared light shielding properties. Average transmittance T 700-800(0deg)AVE The concentration is preferably 0.6% or less, more preferably 0.3% or less, and particularly preferably 0.1% or less. The spectral characteristics (i-4) can be achieved, for example, by using a squarylium dye (described later) as the near-infrared absorbing dye and a phthalic acid glass (described later) as the near-infrared absorbing glass.

[0024] Meeting the spectral characteristics (i-5) means that the near-infrared light region exhibits excellent light shielding properties over a wide range around 1200 nm. Average transmittance T 800-1200(0deg)AVE The amount is preferably 4% or less, and more preferably 3% or less. The spectral characteristics (i-5) can be achieved, for example, by using phthalic acid glass, which will be described later, as the near-infrared absorbing glass.

[0025] The optical filter according to this embodiment preferably satisfies all of the following spectral characteristics (i-6) to (i-7). (i-6) When the dielectric multilayer film 1 side is the incident direction, the average reflectance R1 at a wavelength of 440-650 nm and an incident angle of 5 degrees 440-650(5deg)AVE less than 1.5% (i-7) When the dielectric multilayer film 1 side is the incident direction, the average reflectance R1 at a wavelength of 850 to 1200 nm and an incident angle of 5 degrees 850-1200(5deg)AVE over 60% The spectral characteristics (i-6) to (i-7) substantially reflect the reflection characteristics of the dielectric multilayer film 1, meaning that the dielectric multilayer film 1 has low visible light reflection characteristics and reflects light in the near-infrared region. Average reflectance R1 440-650(5deg)AVE The amount is more preferably 1.3% or less, even more preferably 1.2% or less, and particularly preferably 1.1% or less. Average reflectance R1 850-1200(5deg)AVE It is more preferably 63% or more, even more preferably 65% ​​or more, and particularly preferably 70% or more. Also, if the reflection characteristics in the near-infrared region are too strong, changes in visible light transmittance are likely to occur at high incidence angles, so the average reflectance R1 850-1200(5deg)AVE The percentage is preferably 95% or less, and more preferably 90% or less.

[0026] The optical filter according to this embodiment preferably satisfies the following spectral characteristics (i-8). (i-8) When the dielectric multilayer film 1 side is the incident direction, the average reflectance R1 at a wavelength of 440-650 nm and an incident angle of 60 degrees 440-650(60deg)AVE less than 10% The spectral characteristics (i-8) substantially reflect the reflection characteristics of the dielectric multilayer film 1, meaning that the dielectric multilayer film 1 has low visible light reflection characteristics even at high incidence angles. Average reflectance R1 440-650(60deg)AVE It is more preferably 9% or less, and even more preferably 8.5% or less.

[0027] The optical filter according to this embodiment preferably satisfies all of the following spectral characteristics (i-9) to (i-10). (i-9) When the dielectric multilayer film 2 side is the incident direction, the average reflectance R2 at a wavelength of 440-650 nm and an incident angle of 5 degrees 440-650(5deg)AVE less than 2.0% (i-10) When the dielectric multilayer film 2 side is the incident direction, the average reflectance R2 at a wavelength of 700-850 nm and an incident angle of 5 degrees 700-850(5deg)AVE less than 1.2% The spectral characteristics (i-9) to (i-10) substantially reflect the reflective properties of the dielectric multilayer film 2, meaning that the dielectric multilayer film 2 is an anti-reflective film with low reflective properties in both the visible light region and the near-infrared light region. Average reflectance R2 440-650(5deg)AVE It is more preferably 1.70% or less, and even more preferably 1.53% or less. Average reflectance R2 700-850(5deg)AVE The amount is more preferably 1.1% or less, even more preferably 1.0% or less, and particularly preferably 0.8% or less.

[0028] The optical filter according to this embodiment preferably satisfies all of the following spectral characteristics (i-11) to (i-12). (i-11) When the dielectric multilayer film 2 side is the incident direction, the average reflectance R2 at a wavelength of 440-650 nm and an incident angle of 60 degrees 440-650(60deg)AVE less than 10% (i-12) When the dielectric multilayer film 2 side is the incident direction, the average reflectance R2 at a wavelength of 700-850 nm and an incident angle of 60 degrees 700-850(60deg)AVE 8% or less The spectral characteristics (i-11) to (i-12) substantially reflect the reflective properties of the dielectric multilayer film 2, meaning that the dielectric multilayer film 2 is an anti-reflective film with low reflective properties in both the visible light region and the near-infrared light region, even at high incidence angles. Average reflectance R2 440-650(60deg)AVE It is more preferably 9% or less, and even more preferably 8.5% or less. Average reflectance R2 700-850(60deg)AVE It is more preferably 7.5% or less, even more preferably 7.0% or less, and particularly preferably 6% or less.

[0029] The optical filter according to this embodiment preferably satisfies the following spectral characteristics (i-13). (i-13) When the dielectric multilayer film 1 side is the incident direction, the wavelength IR_R at which the reflectance is 50% at an incident angle of 5 degrees in the wavelength region of 750~900 nm 50(5deg) And, in the wavelength range of 500-700 nm, the wavelength IR_T at which the transmittance is 50% at an incident angle of 5 degrees is... 50(5deg) The absolute value of the difference is 160 nm or more. Satisfying spectral characteristics (i-13) means that the light-shielding region for reflection and the light-shielding region for absorption are separated. The absolute value of the difference in the spectral characteristics (i-13) is more preferably 165 nm or more, even more preferably 170 nm or more, and particularly preferably 185 nm or more.

[0030] The optical filter according to this embodiment preferably satisfies all of the following spectral characteristics (i-14) to (i-15). When the dielectric multilayer film 1 side is the incident direction, the amount of absorption loss at wavelengths X to Y nm X-Y The following definition is given. (absorption loss amount) X-Y )[%] = 100 - (Transmittance at an incident angle of 5 degrees) - (Reflectance at an incident angle of 5 degrees) (i-14) Absorption loss at wavelengths of 700-800 nm 700-800 The average value is 25% or more (i-15) Absorption loss at wavelengths of 850-1000 nm 850-1000The average value is 17% or more A larger absorption loss indicates that light in that wavelength range is being absorbed. Satisfying spectral characteristics (i-14) to (i-15) means that a certain proportion of the spectral characteristics are formed by absorption loss. The larger this proportion, the less variation in spectral characteristics can be expected between perpendicularly incident and obliquely incident light. Absorption loss 700-800 The average value is more preferably 26.5% or higher, and even more preferably 28% or higher. Absorption loss 850-1000 The average value is more preferably 18% or more, and even more preferably 20% or more. The spectral characteristics (i-14) to (i-15) can be achieved, for example, by using a near-infrared absorbing dye having a maximum absorption wavelength in the 700-800 nm range.

[0031] <Near-infrared absorbing glass (fluorite glass)> The near-infrared absorbing glass in the optical filter according to this embodiment is phthalic acid glass containing P, Cu, and F (hereinafter referred to as phthalic acid glass of this embodiment, or simply phthalic acid glass or glass).

[0032] In phthalic acid glass containing P and F, the inclusion of Cu makes it possible to maintain high transmittance of visible light while keeping transmittance of near-infrared light low. Furthermore, the inclusion of F in the glass improves weather resistance, such as moisture resistance.

[0033] The components that can constitute the phthalic acid glass of this embodiment and their preferred content are described below. Unless otherwise specified in this specification, the content of each component and the total content are expressed in mass percent. Furthermore, the transmittance of the glass of this embodiment includes the reflective properties of the glass surface (i.e., not the internal transmittance of the glass).

[0034] In the phthalic acid glass of this embodiment, P is P 5+ It is contained as such. P5+ P is the main component that forms phthalic acid glass and is also an essential component for enhancing near-infrared ray blocking properties. 5+ If the content is 30% or more, the effect is sufficiently obtained, and if it is 70% or less, problems such as glass instability or reduced weather resistance are less likely to occur. Therefore, P 5+ The content is preferably 30-70%, more preferably 31% or more, even more preferably 32% or more, even more preferably 33% or more, more preferably 60% or less, even more preferably 50% or less, even more preferably 45% or less, and most preferably 43% or less. Note P 5+ From the viewpoint of suppressing the erosion of the platinum crucible and inhibiting the volatilization of components, the use of phosphoric acid or a salt thereof is preferred as the raw material.

[0035] In the phthalic acid glass of this embodiment, F is F - It is contained as such. F - F is an essential component for stabilizing glass and improving its weather resistance. In this specification, F is a component contained in glass. - When all other constituent elements are considered to be 100% by mass, the amount of F contained in the glass is - The content of F is shown as an external percentage. - The content of F is preferably 5-70% when calculated as an external percentage. - If the content is 5% or more on an external basis, sufficient weather resistance can be obtained, and if it is 70% or less on an external basis, problems such as a decrease in the transmittance of visible light, a decrease in mechanical properties such as strength, hardness, and elastic modulus, and an increase in ultraviolet transmittance are less likely to occur. More preferably, it is 6% or more on an external basis, even more preferably 8% or more on an external basis, even more preferably 8.5% or more on an external basis, most preferably 10% or more on an external basis, and more preferably 60% or less on an external basis, even more preferably 50% or less on an external basis, even more preferably 40% or less on an external basis, and most preferably 25% or less on an external basis.

[0036] In the phthalic acid glass of this embodiment, Cu is Cu+ or Cu 2+ It is contained as, but in this specification, all are Cu 2+ This indicates the content if it were present as such. Cu 2+ Cu is an essential component for blocking near-infrared rays. 2+ The content is preferably 1-20%. 2+ If the content is 1% or more, the effect of increasing the transmittance of visible light in the glass obtained when co-added with Mo is sufficiently obtained, and if it is 20% or less, problems such as the occurrence of devitrified foreign matter in the glass or a decrease in the transmittance of visible light are less likely to occur. More preferably it is 4.5% or more, even more preferably 6% or more, even more preferably 7.5% or more, most preferably 7.8% or more, more preferably 18% or less, even more preferably 16% or less, even more preferably 13% or less, and most preferably 12% or less.

[0037] Furthermore, the total amount of Cu is the sum of Cu expressed as mass %, including monovalent, divalent, and other existing valencies, and the glass of this embodiment (however, F - When the content of (excluding) is taken as 100% by mass, the range of total Cu content in the glass is preferably 1 to 20% by mass. If the total Cu content is 1% by mass or more, the near-infrared cutting effect can be sufficiently obtained even if the thickness of the glass plate is thin, and if it is 20% by mass or less, the decrease in visible range transmittance can be suppressed. More preferably it is 4.5% or more, even more preferably 6% or more, even more preferably 7.5% or more, most preferably 9% or more, more preferably 18% or less, even more preferably 16% or less, even more preferably 13% or less, and most preferably 11.5% or less. + The mass percentage of the content is (Cu + The value can be determined within a range such that (total amount of Cu) × 100 [%] is between 0.01% and 4.0%.

[0038] Al 3+Al is a component that forms glass and is used to increase the strength and weather resistance of glass. 3+ If it contains Al 3+ If the content is 2% or more, the effect will be sufficiently obtained, and if it is 20% or less, problems such as glass instability or reduced near-infrared ray blocking will not occur. 3+ The content is preferably 0-20%, more preferably 2% or more, even more preferably 3% or more, even more preferably 3.5% or more, most preferably 5% or more, more preferably 18% or less, even more preferably 15% or less, even more preferably 13% or less, and most preferably 10% or less. Al 3+ AlF3, Al2O3, Al(OH)3, etc. can be used as raw materials, and among them, the increase in dissolution temperature and generation of unmelted material, and F - It is preferable to use AlF3 because it is less likely to cause problems such as a decrease in the amount of material used and resulting in glass instability.

[0039] Li + Li is a component used to lower the melting temperature of glass, lower the liquidus temperature of glass, and stabilize glass. + The content of Li is preferably 0-20%. + If the content is 20% or less, problems such as glass instability or reduced near-infrared cut performance are less likely to occur. More preferably it is 18% or less, even more preferably 15% or less, even more preferably 12% or less, and most preferably 10% or less.

[0040] In the phthalic acid glass of this embodiment, Na is Na + It may be contained as such. Na + Na is a component that lowers the melting temperature of glass, lowers the liquidus temperature of glass, and stabilizes glass. +By containing this, when co-added with Mo, the effect of increasing the light transmittance in the visible region of the glass obtained can be sufficiently obtained. The mechanism is explained as follows. Oxygen ions exist around Cu in the fluorophosphate glass, and these oxygen ions are negatively charged. The electric field generated by the negative charge inhibits the movement of electrons (Cu + → Cu 2+ + e - ) and (Mo 6+ + e - → Mo 5+ ) that occur between the said Cu + and Mo 6+ . The presence of Na + in the fluorophosphate glass electrically neutralizes the negative charge of the oxygen ions due to the positive charge carried by Na + . As a result, the movement of electrons occurring between the said Cu + and Mo 5+ is promoted, the proportion of Cu + with light absorption characteristics in the visible region decreases, and the light transmittance in the visible region increases. + Around Cu, oxygen ions exist, and these oxygen ions are negatively charged. The electric field generated by the negative charge inhibits the movement of electrons (Cu + → Cu 2+ + e - ) and (Mo 6+ + e - → Mo 5+ ) that occur between the said Cu + and Mo 6+ . + and Mo 6+ The movement of electrons (e - ) (Cu + → Cu 2+ + e - ) and (Mo 6+ + e - → Mo 5+ ) that occur between the said Cu + and Mo 6+ is inhibited. The presence of Na + in the fluorophosphate glass electrically neutralizes the negative charge of the oxygen ions due to the positive charge carried by Na + . As a result, the movement of electrons occurring between the said Cu + and Mo 5+ is promoted, the proportion of Cu + with light absorption characteristics in the visible region decreases, and the light transmittance in the visible region increases. - ) of movement (Cu + → Cu 2+ + e - ) and (Mo 6+ + e - → Mo 5+ ) + →Cu 2+ +e - ) and (Mo 6+ + e - → Mo 5+ ) 6+ +e - →Mo 5+ ) has an inhibitory effect. The presence of Na + in the fluorophosphate glass electrically neutralizes the negative charge of the oxygen ions due to the positive charge carried by Na + . As a result, the movement of electrons occurring between the said Cu + and Mo 5+ is promoted, the proportion of Cu + with light absorption characteristics in the visible region decreases, and the light transmittance in the visible region increases. + exists, and due to the positive charge carried by Na + , the negative charge of the oxygen ions is electrically neutralized. As a result, the movement of electrons occurring between the said Cu + and Mo 5+ is promoted, the proportion of Cu + with light absorption characteristics in the visible region decreases, and the light transmittance in the visible region increases. + is electrically neutralized by the positive charge carried by Na + . As a result, the movement of electrons occurring between the said Cu + and Mo 5+ is promoted, the proportion of Cu + with light absorption characteristics in the visible region decreases, and the light transmittance in the visible region increases. + and Mo 5+ is promoted, the proportion of Cu + with light absorption characteristics in the visible region decreases, and the light transmittance in the visible region increases. + The proportion of Cu + with light absorption characteristics in the visible region decreases, and the light transmittance in the visible region increases.

[0041] When the glass contains Na + , the content of Na + is preferably 0.1 to 25%. If the content of Na + is 25% or less, the glass is less likely to become unstable. More preferably, it is 0.5% or more, further preferably 1% or more, still more preferably 2% or more, + When the glass contains Na + , the content of Na + is preferably 0.1 to 25%. If the content of Na + is 25% or less, the glass is less likely to become unstable. + is preferably 0.1 to 25%. If the content of Na + is 25% or less, the glass is less likely to become unstable. + If the content of Na + is 25% or less, the glass is less likely to become unstable. More preferably, it is 0.5% or more, further preferably 1% or more, still more preferably 2% or more, Most preferably, it is 3% or more, and more preferably, it is 20% or less, further preferably 18% or less, still more preferably 14% or less, and most preferably 10% or less.

[0042] K + is a component that has effects such as lowering the melting temperature of the glass and lowering the liquid phase temperature of the glass. The content of K + is preferably 0 to 25%. + The content of K + is preferably 0 to 25%. +A content of 25% or less is preferable because it makes the glass less likely to become unstable. More preferably 23% or less, even more preferably 20% or less, even more preferably 18% or less, and most preferably 15% or less.

[0043] R + (Li + na + , and K + One or more components selected from the above are components that lower the melting temperature of the glass, lower the liquidus temperature of the glass, or stabilize the glass. + The total amount, namely Li + na + , and K + Total amount (ΣR + If the concentration is 0.1% or more, the effect is sufficiently obtained, and if it is 30% or less, it is preferable because the glass is less likely to become unstable. Therefore, ΣR + The content is preferably 0.1 to 30%, more preferably 1% or more, even more preferably 3% or more, even more preferably 5% or more, most preferably 8% or more, and more preferably 28% or less. More preferably, it is 27% or less, even more preferably 26% or less, and most preferably 25% or less.

[0044] Mg 2+ This component is used to lower the melting temperature of glass, lower the liquidus temperature of glass, stabilize glass, and increase the strength of glass. 2+ The content is preferably 0-10%. Mg 2+ If the content is 10% or less, problems such as glass instability or reduced near-infrared ray blocking are less likely to occur. More preferably it is 8% or less, even more preferably 6% or less, even more preferably 5% or less, and most preferably 3% or less.

[0045] Ca 2+Ca is a component used to lower the melting temperature of glass, lower the liquidus temperature of glass, stabilize glass, and increase the strength of glass. 2+ The content is preferably 0-20%. 2+ If the content is 20% or less, problems such as glass instability or reduced near-infrared ray blocking are less likely to occur. More preferably it is 0.1% or more, even more preferably 1% or more, even more preferably 2% or more, most preferably 3% or more, and more preferably 18% or less, even more preferably 15% or less, even more preferably 10% or less, and most preferably 6% or less.

[0046] Sr 2+ Sr is a component used to lower the melting temperature of glass, lower the liquidus temperature of glass, and stabilize glass. 2+ The content of Sr is preferably 0-30%. 2+ If the content is 30% or less, problems such as glass instability or reduced near-infrared ray blocking are less likely to occur. More preferably it is 0.1% or more, even more preferably 1% or more, even more preferably 3% or more, most preferably 5% or more, and more preferably 25% or less, even more preferably 20% or less, even more preferably 15% or less, and most preferably 10% or less.

[0047] Ba 2+ Ba is a component used to lower the melting temperature of glass, lower the liquidus temperature of glass, and stabilize glass. 2+ The content of Ba is preferably 0-40%. 2+ If the content is 40% or less, problems such as glass instability or reduced near-infrared ray blocking are less likely to occur. More preferably it is 0.1% or more, even more preferably 5% or more, even more preferably 10% or more, most preferably 15% or more, and more preferably 35% or less, even more preferably 30% or less, even more preferably 25% or less, and most preferably 23% or less.

[0048] R 2+ (Mg 2+ Ca 2+ Sr 2+ , and Ba 2+ One or more components selected from the above are components that lower the melting temperature of the glass, lower the liquidus temperature of the glass, stabilize the glass, etc. 2+ The total amount, i.e., Mg 2+ Ca 2+ Sr 2+ , and Ba 2+ Total amount (ΣR 2+ If the ratio is 10% or more, the effect is sufficiently obtained, and if it is 45% or less, the glass is less likely to become unstable. Therefore, ΣR 2+ The content is preferably 10-45%, more preferably 15% or more, even more preferably 20% or more, even more preferably 23% or more, most preferably 25% or more, more preferably 40% or less, even more preferably 35% or less, even more preferably 33% or less, and most preferably 30% or less.

[0049] Zn 2+ This has effects such as lowering the melting temperature of the glass and lowering the liquidus temperature of the glass. Zn 2+ The content is preferably 0-30%. 2+ If the content is 30% or less, problems such as glass instability, deterioration of glass solubility, and reduction of near-infrared ray blocking properties are less likely to occur. More preferably, it is 20% or less, even more preferably 15% or less, even more preferably 10% or less, and most preferably 5% or less.

[0050] Rb + This component has effects such as lowering the melting temperature of glass and lowering the liquidus temperature of glass. + The content of Rb is preferably 0-10%. +If the content is 10% or less, the glass is less likely to become unstable. More preferably it is 8% or less, even more preferably 6% or less, even more preferably 4% or less, and most preferably 2% or less.

[0051] Cs + Cs is a component that has effects such as lowering the melting temperature of glass and lowering the liquidus temperature of glass. + The content is preferably 0-10%. + If the content is 10% or less, the glass is less likely to become unstable. More preferably it is 8% or less, even more preferably 6% or less, even more preferably 4% or less, and most preferably 2% or less.

[0052] B 3+ It may be included in amounts of 20% or less to stabilize the glass. 3+ If the content is 20% or less, problems such as deterioration of the glass's weather resistance or reduction in near-infrared ray blocking properties are less likely to occur. More preferably, it is 15% or less, even more preferably 10% or less, even more preferably 8% or less, and most preferably 5% or less.

[0053] Mo is Mo 5+ Or Mo 6+ It is contained as, but in this specification, all are Mo 6+ This indicates the content if it were present as such. Mo 6+ This is a component used to increase the transmittance of visible light through glass. Mo is in glass 6+ It is known to exist in a (hexavalent) state. However, when Mo and Cu are co-added to phosphate glass, Cu in the glass + is electron (e - ) releases Cu 2+ Next (Cu + → Cu 2+ +e - ), Cu + The electrons emitted by Mo 6+ Received Mo 5+(5-valent) (Mo 6+ +e - → Mo 5+ ). This results in Cu having absorption characteristics around wavelengths of 300nm to 600nm. + The proportion of (monovalent) decreases, and the transmittance of light with wavelengths of 400 nm to 540 nm increases. 5+ Since it is thought to have the characteristic of absorbing light with a wavelength of around 400 nm, it is not expected that the transmittance of light with a wavelength of around 400 nm will increase.

[0054] Mo 6+ The content is preferably 0-4%. 6+ If it contains, the content is preferably 0.01 to 4%. 6+ If the content is 0.01% or more, a sufficient effect of increasing the transmittance of visible light in the glass can be obtained, and if it is 4% or less, problems such as a decrease in near-infrared cut performance or the occurrence of devitrified foreign matter in the glass are less likely to occur. More preferably it is 0.05% or more, even more preferably 0.1% or more, even more preferably 0.2% or more, most preferably 0.3% or more, even more preferably 3.5% or less, even more preferably 3% or less, even more preferably 2% or less, and most preferably 1% or less.

[0055] Mo 6+ If it contains Mo 6+ and Cu 2+ Content ratio (Mo 6+ / Cu 2+ ) is preferably 0.01 to 0.39 by mass. If it is 0.01 or more, Cu + Absorption of light in the visible light range by can be sufficiently suppressed, and Cu 2+ This can sufficiently promote the absorption of light in the near-infrared region. Also, because it is 0.39 or less, Mo 5+This can suppress the decrease in transmittance in the visible range. More preferably it is 0.02 or higher, even more preferably 0.03 or higher, even more preferably 0.05 or higher, most preferably 0.1 or higher, and more preferably 0.35 or lower, even more preferably 0.3 or lower, even more preferably 0.25 or lower, and most preferably 0.2 or lower.

[0056] In the phthalic acid glass of this embodiment, SiO2, GeO2, ZrO2, SnO2, TiO2, CeO2, WO3, Y2O3, La2O3, Gd2O3, Yb2O3, and Nb2O5 may be included in amounts of 10% or less to improve the weather resistance of the glass. If the content of these components is 10% or less, problems such as the formation of devitrified foreign matter in the glass or a decrease in near-infrared ray blocking performance are less likely to occur. Preferably, the content is 4% or less, more preferably 3% or less, even more preferably 2% or less, and even more preferably 1% or less.

[0057] Fe2O3, Cr2O3, Bi2O3, NiO, V2O5, MnO2, and CoO are all components that reduce the transmittance of visible light when present in glass. Therefore, it is preferable that these components are substantially absent from the glass. Here, substantially absent from the glass means that they are not included except for unavoidable impurities, and that these components are not actively added. Specifically, this means that the content of each of these components in the glass is approximately 100 ppm by mass or less.

[0058] The phthalic acid glass of this embodiment has a thermal expansion coefficient of 60 × 10 in the range of 30°C to 300°C. -7 / ℃~180×10 -7 It is preferable that the temperature is / ℃, which is 65 × 10 -7 / ℃~175×10 -7 / ℃ is more preferable, 70 × 10 -7 / ℃~170×10 -7 / ℃ is even more preferable.

[0059] In the optical filter according to this embodiment, it is preferable that the phthalic acid glass satisfies all of the following spectral characteristics (ii-1) to (ii-3). (ii-1) Wavelength IR_T at which transmittance is 50% at an incident angle of 0 degrees 50(0deg) It is in the wavelength range of 590-640 nm. (ii-2) Transmittance T at a wavelength of 700 nm and an incident angle of 0 degrees 700(0deg) less than 25% (ii-3) Average transmittance T at wavelengths of 700-800 nm and incident angle of 0 degrees 700-800(0deg)AVE less than 10%

[0060] As shown in the spectral characteristics (ii-1) to (ii-3), the near-infrared absorbing glass transmits visible light, with the boundary between the transmission and absorption bands being in the 590-640 nm region, and the absorption band beginning from 700 nm onward. This results in an optical filter with excellent transmittance of visible light and shielding of near-infrared light. Wavelength IR_T 50(0deg) The wavelength is more preferably 590-630 nm, and even more preferably 590-624 nm. Transmittance T 700(0deg) More preferably, it is 20% or less, even more preferably 15% or less, and particularly preferably 10% or less. Average transmittance T 700-800(0deg)AVE It is more preferably 9.8% or less, and even more preferably 9.7% or less.

[0061] In the optical filter according to this embodiment, the phthalic acid glass preferably satisfies the following spectral characteristics (ii-4). This results in an optical filter with excellent shielding properties for near-infrared light beyond 800 nm. (ii-4) Average transmittance T at wavelengths of 800-1200 nm and incident angle of 0 degrees 800-1200(0deg)AVE less than 10% Average transmittance T 800-1200(0deg)AVE It is more preferably 8% or less, and even more preferably 6% or less.

[0062] In the optical filter according to this embodiment, the phthalic acid glass preferably has a thickness of 0.5 mm or less, more preferably 0.4 mm or less. Furthermore, from the viewpoint of maintaining element strength, the thickness is preferably 0.1 mm or more, and more preferably 0.15 mm or more.

[0063] <Dielectric multilayer film> The optical filter according to this embodiment comprises a dielectric multilayer film 1 and a dielectric multilayer film 2. Preferably, at least one of the dielectric multilayer films is designed as a reflective film that reflects a portion of near-infrared light (hereinafter also referred to as the "NIR reflective film"). The other dielectric multilayer film may be a reflective film having a reflection range other than the near-infrared region, or an anti-reflective film.

[0064] The NIR reflective film preferably has wavelength selectivity, for example, that transmits visible light, transmits near-infrared light in the transmission region of the absorption layer, and mainly reflects other near-infrared light.

[0065] As shown in the spectral characteristics (i-5) and (i-7) of the optical filter described above, it is preferable that at least one of the dielectric multilayer films is a reflective film having reflective properties in the near-infrared light region with wavelengths of 850 to 1200 nm, and that it is shielded from light by such properties. By combining the reflection characteristics in this specific wavelength range with the absorption characteristics of a near-infrared absorbing dye having a maximum absorption wavelength of 740-800 nm and phthalic acid glass that mainly absorbs wavelengths of 700-1200 nm, it is possible to block light over a wide area in the near-infrared light region of 700-1200 nm. On the other hand, as shown in the spectral characteristics (i-6) and (i-8) of the optical filter described above, it is preferable that the dielectric multilayer film used as the reflective film exhibits little change in its reflective properties in the visible light region. This results in an optical filter in which the spectral characteristics in the visible light region do not change easily with the angle of incidence, and ripple is reduced. Therefore, it is preferable that at least one dielectric multilayer film be designed as a reflective film that does not reflect visible light but reflects near-infrared light (wavelength 800-1200 nm) at an incident angle of 0 to 60 degrees. The other dielectric multilayer films are preferably designed as anti-reflective layers with low reflectivity in both the visible light region and the near-infrared light region, as shown in the spectral characteristics (i-9) to (i-12) of the optical filter described above.

[0066] A dielectric multilayer film is composed of, for example, dielectric films with different refractive indices stacked on top of each other. More specifically, it can consist of a dielectric film with a low refractive index (low refractive index film), a dielectric film with a medium refractive index (medium refractive index film), and a dielectric film with a high refractive index (high refractive index film), and is composed of two or more of these stacked on top of each other. The high refractive index film preferably has a refractive index of 1.6 or higher at a wavelength of 500 nm, more preferably 1.8 to 2.5, and particularly preferably 2.2 to 2.5. Examples of materials for the high refractive index film include Ta2O5, TiO2, TiO, and Nb2O5. Other commercially available products include OS50 (Ti3O5), OS10 (Ti4O7), OA500 (a mixture of Ta2O5 and ZrO2), and OA600 (a mixture of Ta2O5 and TiO2), all manufactured by Canon Optron. Of these, TiO2 is preferred in terms of film formation properties, reproducibility of refractive index, and stability.

[0067] The medium refractive index film preferably has a refractive index of 1.6 or more and less than 2.2 at a wavelength of 500 nm. Examples of materials for the medium refractive index film include ZrO2, Nb2O5, Al2O3, HfO2, OM-4 and OM-6 (a mixture of Al2O3 and ZrO2) sold by Canon Optron, OA-100, and H4 and M2 (alumina antania) sold by Merck. Of these, Al2O3-based compounds and mixtures of Al2O3 and ZrO2 are preferred in terms of film formation properties, reproducibility in refractive index, and stability.

[0068] The low refractive index film preferably has a refractive index of less than 1.6 at a wavelength of 500 nm, and more preferably 1.38 to 1.5. Examples of materials for the low refractive index film include SiO2 and SiO2. x N y、Examples include MgF2. Other commercially available products include S4F and S5F (a mixture of SiO2 and Al2O3) manufactured by Canon Optron. Of these, SiO2 is preferred in terms of reproducibility, stability, and cost-effectiveness in film formation.

[0069] The dielectric multilayer film preferably has a ratio of 1.6 or higher between [the sum of QWOT T(H) of dielectric films with relatively high refractive indices] and [the sum of QWOT T(L) of dielectric films with relatively low refractive indices]. This makes it easier to obtain a dielectric multilayer film that reflects near-infrared light with wavelengths of 800 to 1100 nm and suppresses reflection of visible light, satisfying the above spectral characteristics, and it is preferable that at least the dielectric multilayer film stacked on the incident light side satisfies this ratio relationship. Here, QWOT (Quarter Wave Optical Thickness) refers to the optical film thickness at λ / 4 of the wavelength, and is calculated from the physical film thickness using the following formula. QWOT = Physical film thickness / Center wavelength (500nm) × 4 × Refractive index at 500nm

[0070] When a dielectric multilayer film is a laminate of a low refractive index film and a high refractive index film, the total QWOT T(H) is the total QWOT of the high refractive index film, and the total QWOT T(L) is the total QWOT of the low refractive index film. Furthermore, if the dielectric multilayer film is a laminate of a low refractive index film and a medium refractive index film, the total QWOT T(H) is the total QWOT of the medium refractive index film, and the total QWOT T(L) is the total QWOT of the low refractive index film. When a dielectric multilayer film is a laminate of a medium refractive index film and a high refractive index film, the total QWOT T(H) is the total QWOT of the high refractive index film, and the total QWOT T(L) is the total QWOT of the medium refractive index film.

[0071] Furthermore, the dielectric multilayer film is preferably a multilayer film in which 10 or more H2 layers and M2 layers, as defined below, are stacked alternately. H2 layer: A single layer with a refractive index of 1.8 to 2.5 and a QWOT of 1.1 to 3.5. M2 layer: A single or multiple layer located between two H2 layers, with a total QWOT of 1.2 to 1.8.

[0072] The specific layered structure described above is a structure in which 10 or more layers are alternately stacked, consisting of a single layer (H2 layer) with a high refractive index and optical thickness, and a layer (M2 layer) whose total optical thickness is within a predetermined range. With such a structure, it is easy to obtain a dielectric multilayer film that reflects near-infrared light with wavelengths of 800 to 1200 nm and has low reflectivity for visible light. The M2 layer may be a single layer or multiple layers as long as it satisfies the predetermined optical thickness requirement. However, from the viewpoint of obtaining smoother spectral characteristics, it is preferable that it be composed of multiple layers. The minimum thickness of a single layer is preferably 5 nm or more, and more preferably 10 nm or more. Furthermore, the refractive index of the dielectric film constituting the M2 layer is preferably the same as or lower than the refractive index of the H2 layer.

[0073] The specific layered structure described above is preferably a dielectric multilayer film designed as at least a reflective film. When a dielectric multilayer film designed as a reflective film has the above-described laminated structure, it is preferable that the H2 layer is the layer closest to the near-infrared absorbing glass among the H2 and M2 layers. The H2 layer closest to the near-infrared absorbing glass may be directly laminated to the near-infrared absorbing glass, or there may be another layer between the H2 layer closest to the near-infrared absorbing glass and the near-infrared absorbing glass that is neither the H2 layer nor the M2 layer.

[0074] For dielectric multilayer films designed as reflective films, the total number of layers of the dielectric multilayer film is preferably 10 or more, more preferably 20 or more, and even more preferably 30 or more. However, as the total number of layers increases, warping and other issues may occur, and the film thickness may increase, so the total number of layers is preferably 110 or less, more preferably 80 or less, and even more preferably 60 or less. Furthermore, the thickness (physical thickness) of the dielectric multilayer film designed as a reflective film is preferably 1 to 6 μm overall.

[0075] When mounting an optical filter to an imaging device, the dielectric multilayer film on the sensor side is usually preferably designed as an anti-reflective layer. The total number of layers of the dielectric multilayer film designed as an anti-reflective layer is preferably 40 layers or less, more preferably 30 layers or less, even more preferably 20 layers or less, and also preferably 6 layers or more. Furthermore, the thickness (physical thickness) of the dielectric multilayer film designed as an anti-reflective layer is preferably 0.2 to 1.0 μm overall.

[0076] For forming dielectric multilayer films, vacuum deposition processes such as CVD, sputtering, and vacuum evaporation, as well as wet deposition processes such as spraying and dipping, can be used.

[0077] When mounting an optical filter in an imaging device, typically the dielectric multilayer film laminated on the glass surface faces the lens side, and the dielectric multilayer film laminated on the resin film surface faces the sensor side. Therefore, in this embodiment, it is preferable to mount the optical filter such that dielectric multilayer film 1 faces the lens side and dielectric multilayer film 2 faces the sensor side.

[0078] <Resin film> The resin film in the optical filter according to this embodiment includes a resin and a near-infrared absorbing dye. Here, the resin refers to the resin that constitutes the resin film.

[0079] As near-infrared absorbing dyes, dyes having a maximum absorption wavelength of 740-800 nm in the resin are preferred. Having a maximum absorption wavelength of 740-800 nm causes the near-infrared light absorption region of phthalic acid glass containing Cu, etc., to be on the shorter wavelength side, allowing for more effective utilization of the spectral characteristics of the dye when combined with glass.

[0080] Examples of near-infrared absorbing dyes include at least one selected from the group consisting of cyanine dyes, phthalocyanine dyes, squarylium dyes, naphthalocyanine dyes, and diimonium dyes, which can be used individually or in combination. Among these, squarylium dyes and cyanine dyes are preferred from the viewpoint of being able to absorb sharply in the 740-800 nm region and thus easily exhibit the effects of the present invention.

[0081] The content of the near-infrared absorbing dye in the resin film is preferably 0.1 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, per 100 parts by mass of resin. When two or more compounds are combined, the above content is the sum of the individual compounds.

[0082] The resin film may contain other dyes, such as ultraviolet light absorbing dyes, as long as they do not impair the effects of the present invention. Examples of ultraviolet light absorbing dyes include oxazole dyes, merocyanine dyes, cyanine dyes, naphthalimide dyes, oxadiazole dyes, oxazine dyes, oxazolidine dyes, naphthalic acid dyes, styryl dyes, anthracene dyes, cyclic carbonyl dyes, and triazole dyes. Among these, merocyanine dyes are particularly preferred. One type may be used alone, or two or more types may be used in combination.

[0083] The resin is not limited to transparent resins, and one or more transparent resins selected from polyester resin, acrylic resin, epoxy resin, ene-thiol resin, polycarbonate resin, polyether resin, polyarylate resin, polysulfone resin, polyethersulfone resin, poly-paraphenylene resin, polyarylene ether phosphine oxide resin, polyamide resin, polyimide resin, polyamide-imide resin, polyolefin resin, cyclic olefin resin, polyurethane resin, and polystyrene resin can be used. These resins may be used individually or in mixtures of two or more. From the viewpoint of the spectral properties of the resin film, glass transition temperature (Tg), and adhesion, one or more resins selected from polyimide resin, polycarbonate resin, polyester resin, and acrylic resin are preferred.

[0084] When multiple dyes are used, they may be contained in the same resin film, or they may each be contained in separate resin films.

[0085] The resin film can be formed by preparing a coating solution by dissolving or dispersing a dye, a resin or resin raw material component, and other components as needed in a solvent, coating this solution onto a support, drying it, and further curing it as necessary. The support in this case may be the near-infrared absorbing glass used in this filter, or a releaseable support used only when forming the resin film. The solvent may be any dispersion medium or solvent that can stably disperse or dissolve the components.

[0086] Furthermore, the coating solution may contain a surfactant to improve voids caused by minute bubbles, indentations caused by the adhesion of foreign matter, and repulsion during the drying process. In addition, methods such as immersion coating, cast coating, or spin coating can be used for applying the coating solution. After applying the above coating solution to the support, a resin film is formed by drying. Furthermore, if the coating solution contains raw material components of a transparent resin, a curing treatment such as thermosetting or photocuring is performed.

[0087] Furthermore, the resin film can also be manufactured in film form by extrusion molding. The resulting film-like resin film can be laminated onto phosphate glass and integrated by thermocompression bonding or the like to produce a substrate.

[0088] The resin film may be present as one layer within the optical filter, or as two or more layers. If there are two or more layers, each layer may have the same configuration or different configurations. Furthermore, if there are two or more resin films, they may all be laminated on the same main surface side of the near-infrared absorbing glass, or they may be laminated on different main surfaces.

[0089] The thickness of the resin film is preferably 10 μm or less, more preferably 5 μm or less, from the viewpoint of in-plane film thickness distribution within the substrate after coating and appearance quality, and preferably 0.5 μm or more from the viewpoint of exhibiting desired spectral characteristics with an appropriate dye concentration. If the optical filter has two or more resin film layers, it is preferable that the total thickness of each resin film is within the above range.

[0090] In the optical filter according to this embodiment, it is preferable that the resin film satisfies all of the following spectral characteristics (iv-1) to (iv-4). (iv-1) Average internal transmittance T at wavelengths of 440-600 nm and incident angle of 0 degrees (in)440-600(0deg)AVE over 90% (iv-2) Wavelength IR_T at which the internal transmittance is 50% at an incident angle of 0 degrees (in)50(0deg) It is in the wavelength range of 630-645 nm. (iv-3) The wavelength IR_T at which the internal transmittance is 70% at an incident angle of 0 degrees in the wavelength range of 500-700 nm. (in)70(0deg) And, the wavelength IR_T at which the transmittance is 20% at an incident angle of 0 degrees (in)20(0deg) The absolute value of the difference is 60 nm or less. (iv-4) Average internal transmittance T at wavelengths of 700-800 nm and incident angle of 0 degrees (in)700-800(0deg)AVE less than 5% As shown in spectral characteristics (iv-1), the resin film has high visible light transmittance, as shown in spectral characteristics (iv-2), the wavelength 630-645 nm is the boundary region between the transmission and absorption regions, as shown in spectral characteristics (iv-3), the absorption characteristics in the boundary region are steep, and as shown in spectral characteristics (iv-4), it has high shielding ability for near-infrared light at wavelengths of 700-800 nm.

[0091] Average internal transmittance T (in)440-600(0deg)AVE It is more preferably 90.5% or more, and even more preferably 91% or more. Wavelength IR_T (in)50(0deg) The wavelength is more preferably 632-640 nm, and even more preferably 634-640 nm. The absolute value of the difference in (iv-3) is more preferably 57 nm or less, and even more preferably 55 nm or less. Average internal transmittance T (in)700-800(0deg)AVEIt is more preferably 4% or less, and even more preferably 3% or less.

[0092] Furthermore, it is preferable that the substrate having the above-mentioned near-infrared absorbing glass and resin film satisfies all of the following spectral characteristics (iii-1) to (iii-3). (iii-1) Average internal transmittance T at wavelengths of 440-600 nm and incident angle of 0 degrees (in)440-600(0deg)AVE over 75% (iii-2) Average internal transmittance T at wavelength 700-800 nm and incident angle 0 degrees (in)700-800(0deg)AVE less than 1.2% (iii-3) Average internal transmittance T at wavelengths of 800-1000 nm and incident angle of 0 degrees (in)800-1000(0deg)AVE less than 5% As shown in the spectral characteristics (iii-1) to (iii-3), the substrate combining glass and near-infrared absorbing dye has high visible light transmittance and high near-infrared absorption characteristics in the 700-1000 nm range. Average internal transmittance T (in)440-600(0deg)AVE It is more preferably 76% or more, and even more preferably 77% or more. Average internal transmittance T (in)700-800(0deg)AVE It is more preferably 1.1% or less, and even more preferably 1.05% or less. Average internal transmittance T (in)800-1000(0deg)AVE It is more preferably 4.5% or less, and even more preferably 4.0% or less.

[0093] The optical filter of this embodiment may also include other components, such as a component (layer) that provides absorption by inorganic fine particles to control the transmission and absorption of light in a specific wavelength range. Specific examples of inorganic fine particles include ITO (Indium Tin Oxides), ATO (Antimony-doped Tin Oxides), cesium tungstate, and lanthanum boride. ITO fine particles and cesium tungstate fine particles have high transmittance of visible light and light absorption over a wide range in the infrared wavelength region exceeding 1200 nm, and can therefore be used when shielding against such infrared light is required.

[0094] The optical filter of this embodiment can provide an imaging device with excellent color reproduction when used, for example, in an imaging device such as a digital still camera. Such an imaging device comprises a solid-state image sensor, an imaging lens, and the optical filter of this embodiment. The optical filter of this embodiment can be used, for example, by being placed between the imaging lens and the solid-state image sensor, or by being directly attached to the solid-state image sensor, imaging lens, etc. of the imaging device via an adhesive layer.

[0095] As described above, the following optical filters and the like are disclosed in this specification. [1] An optical filter comprising, in this order, a dielectric multilayer film 1, a substrate having near-infrared absorbing glass and a resin film, and a dielectric multilayer film 2, The aforementioned resin film contains a near-infrared absorbing dye and a resin, The near-infrared absorbing glass is a phthalic acid glass containing P, Cu, and F. The optical filter is an optical filter that satisfies all of the following spectral characteristics (i-1) to (i-5). (i-1) Average transmittance T at wavelengths of 440-600 nm and incident angle of 0 degrees 440-600(0deg)AVE And the average transmittance T at a wavelength of 440-600 nm and an incident angle of 60 degrees. 440-600(60deg)AVE The absolute value of the difference is 15% or less. (i-2) The average transmittance T 440-600(0deg)AVE over 75% (i-3) Wavelength IR_T at which transmittance is 50% at an incident angle of 0 degrees 50(0deg) It is in the wavelength range of 580-640 nm. (i-4) Average transmittance T at wavelengths of 700-800 nm and an incident angle of 0 degrees 700-800(0deg)AVE less than 1.1% (i-5) Average transmittance T at wavelengths of 800-1200 nm and incident angle of 0 degrees 800-1200(0deg)AVE less than 5% [2] The optical filter according to [1], wherein the optical filter satisfies all of the following spectral characteristics (i-6) to (i-7). (i-6) When the dielectric multilayer film 1 side is the incident direction, the average reflectance R1 at a wavelength of 440-650 nm and an incident angle of 5 degrees 440-650(5deg)AVE less than 1.5% (i-7) When the dielectric multilayer film 1 side is the incident direction, the average reflectance R1 at a wavelength of 850 to 1200 nm and an incident angle of 5 degrees 850-1200(5deg)AVE over 60% [3] The optical filter according to [1] or [2], wherein the optical filter satisfies the following spectral characteristics (i-8). (i-8) When the dielectric multilayer film 1 side is the incident direction, the average reflectance R1 at a wavelength of 440-650 nm and an incident angle of 60 degrees 440-650(60deg)AVE less than 10% [4] An optical filter according to any one of [1] to [3], wherein the optical filter satisfies all of the following spectral characteristics (i-9) to (i-10). (i-9) When the dielectric multilayer film 2 side is the incident direction, the average reflectance R2 at a wavelength of 440-650 nm and an incident angle of 5 degrees 440-650(5deg)AVE less than 2.0% (i-10) When the dielectric multilayer film 2 side is the incident direction, the average reflectance R2 at a wavelength of 700-850 nm and an incident angle of 5 degrees 700-850(5deg)AVE less than 1.2% [5] An optical filter according to any one of [1] to [4], wherein the optical filter satisfies all of the following spectral characteristics (i-11) to (i-12). (i-11) When the dielectric multilayer film 2 side is the incident direction, the average reflectance R2 at a wavelength of 440-650 nm and an incident angle of 60 degrees 440-650(60deg)AVE less than 10% (i-12) When the dielectric multilayer film 2 side is the incident direction, the average reflectance R2 at a wavelength of 700-850 nm and an incident angle of 60 degrees 700-850(60deg)AVE 8% or less [6] An optical filter according to any one of [1] to [5], wherein the optical filter satisfies the following spectral characteristics (i-13). (i-13) When the dielectric multilayer film 1 side is the incident direction, the wavelength IR_R at which the reflectance is 50% at an incident angle of 5 degrees in the wavelength region of 750~900 nm 50(5deg) And, in the wavelength range of 580-640 nm, the wavelength IR_T at which the transmittance is 50% at an incident angle of 5 degrees is... 50(5deg) The absolute value of the difference is 160 nm or more. [7] An optical filter according to any one of [1] to [6], wherein the optical filter satisfies all of the following spectral characteristics (i-14) to (i-15). When the dielectric multilayer film 1 side is the incident direction, the amount of absorption loss at wavelengths X to Y nm X-Y The following definition is given. (absorption loss amount) X-Y )[%] = 100 - (Transmittance at an incident angle of 5 degrees) - (Reflectance at an incident angle of 5 degrees) (i-14) Absorption loss at wavelengths of 700-800 nm 700-800 The average value is 25% or more (i-15) Absorption loss at wavelengths of 850-1000 nm 850-1000 The average value is 17% or more [8] The thickness of the near-infrared absorbing glass is 0.4 mm or less, The optical filter according to any one of [1] to [7], wherein the near-infrared absorbing glass satisfies all of the following spectral characteristics (ii-1) to (ii-3). (ii-1) Wavelength IR_T at which transmittance is 50% at an incident angle of 0 degrees 50(0deg) It is in the wavelength range of 590-640 nm. (ii-2) Transmittance T at a wavelength of 700 nm and an incident angle of 0 degrees 700(0deg) less than 25% (ii-3) Average transmittance T at wavelengths of 700-800 nm and incident angle of 0 degrees 700-800(0deg)AVE less than 10% [9] An optical filter according to any one of [1] to [8], wherein the substrate satisfies all of the following spectral characteristics (iii-1) to (iii-3). (iii-1) Average internal transmittance T at wavelengths of 440-600 nm and incident angle of 0 degrees (in)440-600(0deg)AVE over 75% (iii-2) Average internal transmittance T at wavelength 700-800 nm and incident angle 0 degrees (in)700-800(0deg)AVE less than 1.2% (iii-3) Average internal transmittance T at wavelengths of 800-1000 nm and incident angle of 0 degrees (in)800-1000(0deg)AVE less than 5%

[10] The optical filter according to any one of [1] to [9], wherein the near-infrared absorbing dye comprises a squarylium dye having a maximum absorption wavelength of 740 to 800 nm in the resin.

[11] An optical filter according to any one of [1] to

[10] , wherein the resin film satisfies all of the following spectral characteristics (iv-1) to (iv-4). (iv-1) Average internal transmittance T at wavelengths of 440-600 nm and incident angle of 0 degrees (in)440-600(0deg)AVE over 90% (iv-2) Wavelength IR_T at which the internal transmittance is 50% at an incident angle of 0 degrees (in)50(0deg) It is in the wavelength range of 630-645 nm. (iv-3) The wavelength IR_T at which the internal transmittance is 70% at an incident angle of 0 degrees in the wavelength range of 500-700 nm. (in)70(0deg) And, the wavelength IR_T at which the transmittance is 20% at an incident angle of 0 degrees (in)20(0deg) The absolute value of the difference is 60 nm or less. (iv-4) Average internal transmittance T at wavelengths of 700-800 nm and incident angle of 0 degrees (in)700-800(0deg)AVE less than 5%

[12] The near-infrared absorbing glass is Expressed in mass percentage, P 5+ :30~70% Al 3+ : 0~20% Li + : 0~20% Na + : 0~25% K + : 0~25% Mg 2+ : 0~10% Ca 2+ : 0~20% Sr 2+ : 0-30% Ba 2+ : 0~40% ΣR + :0.1~30%(R + Li + na + , and K + (One or more ingredients selected from) ΣR 2+ :10~45%(R 2+Mg 2+ Ca 2+ Sr 2+ , and Ba 2+ (one or more ingredients selected from), and Cu 2+ :1~20% It contains F contained in the glass. - When the other constituent elements are assumed to be 100% by mass, F - An optical filter according to any one of [1] to

[11] , which is a phthalic acid glass containing 5 to 70% by mass of the externally divided portion. An imaging device equipped with an optical filter as described in any one of [1] to

[12] . [Examples]

[0096] Next, the present invention will be described in more detail with reference to examples. A UV-Vis spectrophotometer (Hitachi High-Technologies Corporation, Model UH-4150) was used to measure each spectral characteristic. Note that unless the angle of incidence is specifically stated, the spectral characteristics are measured at an angle of incidence of 0 degrees (perpendicular to the main surface of the optical filter).

[0097] The dyes used in each example are as follows: Compound 1 (cyanine compound): Synthesized according to the method described in Dyes and Pigments, 73, 344-352 (2007). Compound 2 (squallium compound): Synthesized according to International Publication No. 2017 / 135359. Compound 3 (merocyanine compound): Synthesized according to German Patent Publication No. 10109243. Compound 4 (squallium compound): Synthesized according to Japanese Patent Publication No. 2017-110209. Compound 5 (squallium compound): Synthesized according to International Publication No. 2014 / 088063 and International Publication No. 2016 / 133099.

[0098] [ka]

[0099] The maximum absorption wavelengths of each dye in polyimide resin are shown in Table 2 below.

[0100] <Spectral properties of glass> Glass A1, Glass A2, Glass B, Glass C, Glass D1, and Glass D2, as shown in Table 1, were prepared for use in the examples and comparative examples. Note that glass A1, glass A2, glass B, glass D1, and glass D2 are phthalic acid glass, and glass C is phosphoric acid glass.

[0101] The spectral characteristics of each glass are shown in Table 1 below.

[0102] [Table 1]

[0103] As shown above, phthalic acid glass has high transmittance in the visible light region and excellent light-blocking properties in the near-infrared region, and is particularly excellent at blocking light with wavelengths of 700nm to 800nm.

[0104] <Example 1: Optical filter> A resin film was formed on one main surface of a phthalic acid glass substrate A1 using the method described below to produce a substrate having a glass substrate and a resin film. First, polyimide resin ("C3G30G" (product name), manufactured by Mitsubishi Gas Chemical Company, Inc., refractive index 1.59) was dissolved in γ-butyrolactone (GBL):cyclohexanone = 1:1 (mass ratio) to prepare a polyimide resin solution with a resin concentration of 8.5% by mass. Each of the above dyes was added to the resin solution at the concentrations shown in Table 2 below, per 100 parts by mass of resin, and a coating solution was obtained by stirring and dissolving at 50°C for 2 hours. The obtained coating solution was applied to the glass substrate by spin coating to form a resin film 1 with a film thickness of approximately 3 μm. A dielectric multilayer film 1 was formed on the other main surface of a glass substrate by depositing TiO2 and SiO2 in the configuration shown in Table 3 below. Furthermore, a dielectric multilayer film 2 was formed on the surface of a resin film by depositing TiO2 and SiO2 in the configuration shown in Table 4 below. In this way, an optical filter having the configuration of dielectric multilayer film 1 (Table 3) / phthalic acid glass A1 / resin film 1 / dielectric multilayer film 2 (Table 4) was fabricated.

[0105] <Examples 2-12: Optical filters> An optical filter was fabricated in the same manner as in Example 1, except that the glass, resin film, dielectric multilayer film 1, and dielectric multilayer film 2 were changed to the configurations shown below. The configurations of each dielectric multilayer film are shown in Tables 3 to 6. Example 2: Dielectric multilayer film 1 (Table 3) / Fluorine glass A2 / Resin film 1 / Dielectric multilayer film 2 (Table 4) Example 3: Dielectric multilayer film 1 (Table 3) / Fluorine glass B / Resin film 1 / Dielectric multilayer film 2 (Table 4) Example 4: Dielectric multilayer film 1 (Table 3) / Phosphate glass C / Resin film 1 / Dielectric multilayer film 2 (Table 4) Example 5: Dielectric multilayer film 1 (Table 5) / Fluorine glass A1 / Resin film 1 / Dielectric multilayer film 2 (Table 4) Example 6: Dielectric multilayer film 1 (Table 3) / Fluorine glass A1 / Resin film 2 / Dielectric multilayer film 2 (Table 4) Example 7: Dielectric multilayer film 1 (Table 3) / Fluorine glass D2 / Resin film 1 / Dielectric multilayer film 2 (Table 4) Example 8: Dielectric multilayer film 1 (Table 3) / Fluorine glass D1 / Resin film 3 / Dielectric multilayer film 2 (Table 4) Example 9: Dielectric multilayer film 1 (Table 6) / Fluorine glass D1 / Resin film 3 / Dielectric multilayer film 2 (Table 4) Example 10: Dielectric multilayer film 1 (Table 6) / Fluorine glass D2 / Resin film 3 / Dielectric multilayer film 2 (Table 4) Example 11: Dielectric multilayer film 1 (Table 6) / Fluorine glass D1 / Resin film 4 / Dielectric multilayer film 2 (Table 4) Example 12: Dielectric multilayer film 1 (Table 6) / Fluorine glass D2 / Resin film 4 / Dielectric multilayer film 2 (Table 4)

[0106] For each resin film, the spectral transmittance curve was measured at an incident angle of 0 degrees in the wavelength range of 300 to 1200 nm using an ultraviolet-visible spectrophotometer. The spectral characteristics of each resin film are as follows: To avoid the effects of reflection at the air interface and the glass interface, the resin film formed on a transparent glass substrate was evaluated using its internal transmittance. The results are shown in Table 2 below.

[0107] For each substrate (resin film and glass substrate), spectral transmittance curves were measured at an incident angle of 0 degrees in the wavelength range of 300 to 1200 nm using an ultraviolet-visible spectrophotometer. To avoid the influence of reflection at the air and glass interfaces, the spectral characteristics of each substrate were evaluated using internal transmittance. The results are shown in Table 6 below.

[0108] For each optical filter, spectral transmittance curves at incident angles of 0 and 60 degrees, and spectral reflectance curves at an incident angle of 5 degrees were measured using an ultraviolet-visible spectrophotometer in the wavelength range of 300 to 1200 nm. The results are shown in Tables 7 and 8 below.

[0109] Furthermore, the spectral transmittance curve of the optical filter in Example 1 is shown in Figure 2, the spectral reflectance curve on the dielectric multilayer film 1 side when the incident direction is shown in Figure 3, and the spectral reflectance curve on the dielectric multilayer film 2 side when the incident direction is shown in Figure 4. The spectral transmittance curve of the optical filter in Example 2 is shown in Figure 5, and the spectral reflectance curve on the dielectric multilayer film 1 side when the incident direction is shown in Figure 6. The spectral transmittance curves of the optical filters in Examples 3 to 6 are shown in Figures 7 to 10, respectively. Examples 1-2, 4, and 6-12 are examples, while Examples 3 and 5 are comparative examples.

[0110] [Table 2]

[0111] [Table 3]

[0112]

Table 4

[0113]

Table 5

[0114]

Table 6

[0115]

Table 7

[0116]

Table 8

[0117] From the above results, the optical filters of Example 1, Example 2, Example 4, and Example 6 to Example 12 have an absolute value of the difference between the average transmittance T 440-600(0deg)AVE and the average transmittance T 440-600(60deg)AVE of 15% or less, and even at a high incident angle of 60 degrees, the change in visible light transmittance is small. Also, the average transmittance T 440-600(0deg)AVE is 75% or more, maintaining a high visible light transmittance. Also, the wavelength IR_T 50(0deg) at which the transmittance becomes 50% at an incident angle of 0 degrees is in the range of 580 to 640 nm, efficiently capturing visible transmitted light by blocking the near-infrared light region. Furthermore, the average transmittance T 700-800(0deg)AVE is 1.1% or less and the average transmittance T 800-1200(0deg)AVE is 5% or less, showing excellent shielding properties for near-infrared light over a wide range. On the other hand, the optical filter of Example 3 has an average transmittance T 800-1200(0deg)AVE exceeding 5%, and has low shielding properties for near-infrared light. This is due to insufficient absorption of the glass substrate. The optical filter of Example 5 has an average transmittance T 440-600(0deg)AVE and an average transmittance T 440-600(60deg)AVEThe absolute value of the difference exceeds 15%, indicating a large change in visible light transmittance at high incidence angles. This is due to the high reflectance of dielectric multilayer film 1 in the near-infrared region.

[0118] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. This application is based on Japanese Patent Application No. 2022-210260, filed on 27 December 2022, the contents of which are incorporated herein by reference. [Industrial applicability]

[0119] The optical filter of this embodiment has excellent weather resistance, exhibits minimal change in spectral characteristics even at high incidence angles, has excellent transmittance in the visible light region, and possesses excellent shielding properties in the near-infrared region, particularly over a wide range including 1200 nm. It is useful in applications such as imaging devices like cameras and sensors for transport aircraft, where performance has been steadily increasing in recent years. [Explanation of Symbols]

[0120] 1B…Optical filter 10…Near-infrared absorbing glass 21, 22… Dielectric multilayer film 30… Resin film 40...Base material

Claims

1. An optical filter comprising, in this order, a dielectric multilayer film 1, a substrate having near-infrared absorbing glass and a resin film, and a dielectric multilayer film 2, The aforementioned resin film contains a near-infrared absorbing dye and a resin, The near-infrared absorbing glass is a fluorine-based glass containing P, Cu, and F. The optical filter is an optical filter that satisfies all of the following spectral characteristics (i-1) to (i-3), (i-5), and (i-6). (i-1) Average transmittance T at wavelengths of 440-600 nm and incident angle of 0 degrees ４４０－６００（０ｄｅｇ）ＡＶＥ And the average transmittance T at wavelengths of 440-600 nm and an incident angle of 60 degrees. ４４０－６００（６０ｄｅｇ）ＡＶＥ The absolute value of the difference is 15% or less. (i-2) The average transmittance T is previously recorded. ４４０－６００（０ｄｅｇ）ＡＶＥ が75% and above (i-3) Wavelength IR_T at which the transmittance is 50% at an incident angle of 0 degrees ５０（０ｄｅｇ） It is in the wavelength range of 580-640 nm. (i-5) Average transmittance T at wavelengths of 800-1200 nm and incident angle of 0 degrees ８００－１２００（０ｄｅｇ）ＡＶＥ less than 5% (i-6) When the dielectric multilayer film 1 side is the incident direction, the average reflectance R1 at a wavelength of 440 to 650 nm and an incident angle of 5 degrees ４４０－６５０（５ｄｅｇ）ＡＶＥ less than 1.5%

2. An optical filter comprising, in this order, a dielectric multilayer film 1, a substrate having near-infrared absorbing glass and a resin film, and a dielectric multilayer film 2, The aforementioned resin film contains a near-infrared absorbing dye and a resin, The near-infrared absorbing glass is a fluorine-based glass containing P, Cu, and F. The optical filter is an optical filter that satisfies all of the following spectral characteristics (i-1) to (i-3), (i-5), and (i-7). (i-1) Average transmittance T at wavelengths of 440-600 nm and incident angle of 0 degrees ４４０－６００（０ｄｅｇ）ＡＶＥ And the average transmittance T at wavelengths of 440-600 nm and an incident angle of 60 degrees. ４４０－６００（６０ｄｅｇ）ＡＶＥ The absolute value of the difference is 15% or less. (i-2) The average transmittance T is previously recorded. ４４０－６００（０ｄｅｇ）ＡＶＥ が75% and above (i-3) Wavelength IR_T at which the transmittance is 50% at an incident angle of 0 degrees ５０（０ｄｅｇ） It is in the wavelength range of 580-640 nm. (i-5) Average transmittance T at wavelengths of 800-1200 nm and incident angle of 0 degrees ８００－１２００（０ｄｅｇ）ＡＶＥ less than 5% (i-7) When the dielectric multilayer film 1 side is the incident direction, the average reflectance R1 at a wavelength of 850 to 1200 nm and an incident angle of 5 degrees ８５０－１２００（５ｄｅｇ）ＡＶＥ over 60%

3. The optical filter according to claim 1 or 2, wherein the optical filter satisfies the following spectral characteristics (i-4). (i-4) Average transmittance T at wavelengths of 700-800 nm and incident angle of 0 degrees ７００－８００（０ｄｅｇ）ＡＶＥ less than 1.1%

4. The optical filter according to claim 1 or 2, wherein the optical filter satisfies the following spectral characteristics (i-8). (i-8) When the dielectric multilayer film 1 side is the incident direction, the average reflectance R1 at a wavelength of 440 to 650 nm and an incident angle of 60 degrees ４４０－６５０（６０ｄｅｇ）ＡＶＥ less than 10%

5. The optical filter according to claim 1 or 2, wherein the optical filter satisfies all of the following spectral characteristics (i-9) to (i-10). (i-9) When the dielectric multilayer film 2 side is the incident direction, the average reflectance R2 at a wavelength of 440 to 650 nm and an incident angle of 5 degrees ４４０－６５０（５ｄｅｇ）ＡＶＥ less than 2.0% (i-10) When the dielectric multilayer film 2 side is the incident direction, the average reflectance R2 at a wavelength of 700 to 850 nm and an incident angle of 5 degrees ７００－８５０（５ｄｅｇ）ＡＶＥ less than 1.2%

6. The optical filter according to claim 1 or 2, wherein the optical filter satisfies all of the following spectral characteristics (i-11) to (i-12). (i-11) When the dielectric multilayer film 2 side is the incident direction, the average reflectance R2 at a wavelength of 440 to 650 nm and an incident angle of 60 degrees ４４０－６５０（６０ｄｅｇ）ＡＶＥ less than 10% (i-12) When the dielectric multilayer film 2 side is the incident direction, the average reflectance R2 at a wavelength of 700 to 850 nm and an incident angle of 60 degrees ７００－８５０（６０ｄｅｇ）ＡＶＥ 8% or less

7. The optical filter according to claim 1 or 2, wherein the optical filter satisfies the following spectral characteristics (i-13). (i-13) When the dielectric multilayer film 1 is the incident direction, the wavelength IR_R at which the reflectance is 50% at an incident angle of 5 degrees in the wavelength region of 750 to 900 nm ５０（５ｄｅｇ） And, in the wavelength range of 580-640 nm, the wavelength IR_T at which the transmittance is 50% at an incident angle of 5 degrees is... ５０（５ｄｅｇ） The absolute value of the difference is 160 nm or more.

8. The optical filter according to claim 1 or 2, wherein the optical filter satisfies all of the following spectral characteristics (i-14) to (i-15). When the dielectric multilayer film 1 side is the incident direction, the amount of absorption loss in wavelengths X to Y nm Ｘ－Ｙ The following definition is given. (Absorption loss amount) Ｘ－Ｙ ) [%] = 100 - (Transmittance at an incident angle of 5 degrees) - (Reflectance at an incident angle of 5 degrees) (i-14) Absorption loss at wavelengths of 700-800 nm ７００－８００ The average value is 25% or more (i-15) Absorption loss at wavelengths of 850-1000 nm ８５０－１０００ The average value is 17% or more

9. The thickness of the near-infrared absorbing glass is 0.4 mm or less. The near-infrared absorbing glass satisfies all of the following spectral characteristics (ii-1) to (ii-3): The optical filter according to claim 1 or 2. (ii-1) Wavelength IR_T at which the transmittance is 50% at an incident angle of 0 degrees ５０（０ｄｅｇ） It is in the wavelength range of 590-640 nm. (ii-2) Transmittance T at a wavelength of 700 nm and an incident angle of 0 degrees ７００（０ｄｅｇ） less than 25% (ii-3) Average transmittance T at wavelengths of 700-800 nm and incident angle of 0 degrees ７００－８００（０ｄｅｇ）ＡＶＥ less than 10%

10. The optical filter according to claim 1 or 2, wherein the substrate satisfies all of the following spectral characteristics (iii-1) to (iii-3). (iii-1) Average internal transmittance T at wavelengths of 440-600 nm and incident angle of 0 degrees （ｉｎ）４４０－６００（０ｄｅｇ）ＡＶＥ over 75% (iii-2) Average internal transmittance T at wavelengths of 700-800 nm and incident angle of 0 degrees （ｉｎ）７００－８００（０ｄｅｇ）ＡＶＥ less than 1.2% (iii-3) Average internal transmittance T at wavelengths of 800-1000 nm and incident angle of 0 degrees （ｉｎ）８００－１０００（０ｄｅｇ）ＡＶＥ less than 5%

11. The optical filter according to claim 1 or 2, wherein the near-infrared absorbing dye comprises a squarylium dye having a maximum absorption wavelength of 740 to 800 nm in the resin.

12. The optical filter according to claim 1 or 2, wherein the resin film satisfies all of the following spectral characteristics (iv-1) to (iv-4). (iv-1) Average internal transmittance T at wavelengths of 440-600 nm and incident angle of 0 degrees （ｉｎ）４４０－６００（０ｄｅｇ）ＡＶＥ over 90% (iv-2) Wavelength IR_T at which the internal transmittance is 50% at an incident angle of 0 degrees （ｉｎ）５０（０ｄｅｇ） It is in the wavelength range of 630-645 nm. (iv-3) The wavelength IR_T at which the internal transmittance is 70% at an incident angle of 0 degrees in the wavelength range of 500-700 nm. （ｉｎ）７０（０ｄｅｇ） And the wavelength IR_T at which the transmittance is 20% at an incident angle of 0 degrees. （ｉｎ）２０（０ｄｅｇ） The absolute value of the difference is 60 nm or less. (iv-4) Average internal transmittance T at wavelengths of 700-800 nm and incident angle of 0 degrees （ｉｎ）７００－８００（０ｄｅｇ）ＡＶＥ less than 5%

13. The aforementioned near-infrared absorbing glass, Expressed in mass percentage, P ５＋ :30~70% Al ３＋ :0~20% Li ＋ :0~20% No ＋ :0~25% K ＋ :0~25% Mg ２＋ :0~10% Ca ２＋ :0~20% Sr ２＋ :0~30% No ２＋ :0~40% ΣR ＋ :0.1~30%(R ＋ Li ＋ Na ＋ , and K ＋ (One or more ingredients selected from) ΣR ２＋ : 10-45% (R ２＋ Mg ２＋ Ca ２＋ , Sr ２＋ , and Ba ２＋ (one or more ingredients selected from), and Cổ ２＋ :1~20% It contains F contained in the glass. － When the other constituent elements are assumed to be 100% by mass, F － The optical filter according to claim 1 or 2, wherein the optical filter is a phthalic acid glass containing 5 to 70% by mass of the externally divided portion.

14. An imaging apparatus comprising the optical filter described in claim 1 or 2.

Images