Optical filter

Abstract

To provide an optical filter, even in a high incidence angle, having little variations in transmissivity in a visible light region, and having excellent transparency in the visible light region and shielding properties in a near infrared light region.SOLUTION: An optical filter according to the present invention comprises a base material and a dielectric multilayer film stacked as an outermost layer on at least one main surface side of the base material. The base material has a near infrared ray absorption glass and a resin film. The resin film is 10 μm or less in thickness, and includes a resin and a dye (NIR1). The optical filter satisfies all of predetermined spectral characteristics (i-1) to (i-3), (i-6) to (i-8), etc.SELECTED DRAWING: Figure 1

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] Such optical filters can take various forms, such as reflective filters that alternately stack dielectric thin films with different refractive indices on one or both sides of a transparent substrate (dielectric multilayer film) and reflect the light to be blocked by utilizing light interference.

[0004] Patent documents 1 and 2 describe optical filters having a dielectric multilayer film and an absorption layer containing a dye. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2019 / 151348 [Patent Document 2] International Publication No. 2018 / 043564 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Optical filters with dielectric multilayer films present a problem because the optical thickness of the dielectric multilayer film changes with the angle of incidence of light, resulting in changes in the spectral transmittance curve with respect to the angle of incidence. For example, depending on the number of layers of the multilayer film, interference caused by reflected light at each layer interface can cause a sharp change in transmittance in the visible light region, known as ripple, which tends to occur more strongly at larger angles of incidence. Using such filters may affect the spectral sensitivity of solid-state image sensors. 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.

[0007] The present invention aims to provide an optical filter that exhibits minimal change in transmittance in the visible light region even at high incidence angles, and has excellent transmittance in the visible light region and shielding properties in the near-infrared light region. [Means for solving the problem]

[0008] The present invention provides an optical filter and the like having the following configuration. [1] An optical filter comprising a substrate, a dielectric multilayer film 1 on one main surface side of the substrate, and a dielectric multilayer film 2 on the other main surface side of the substrate, The substrate comprises near-infrared absorbing glass and a resin film. The aforementioned resin film has a thickness of 10 μm or less and contains a resin and a dye (NIR1). The optical filter satisfies all of the following spectral characteristics (i-1) to (i-3) and (i-6) to (i-8), In the spectral transmittance curve at an incident angle of 0 degrees, the maximum transmittance T is observed at wavelengths of 750-1000 nm. 750-1000(0deg)MAX The percentage is 2.6% or less. In the spectral transmittance curve at an incident angle of 50 degrees, the maximum transmittance T is observed at wavelengths of 750-1000 nm. 750-1000(50deg)MAX An optical filter with a viscosity of 3% or less. (i-1) In the spectral transmittance curve at an incident angle of 0 degrees, the average transmittance T for wavelengths of 450-600 nm 450-600(0deg)AVE over 80% (i-2) In the spectral transmittance curve at an incident angle of 50 degrees, the average transmittance T for wavelengths of 450-600 nm450-600(50deg)AVE is 80% or more (i-3) the average transmittance T 450-600(0deg)AVE and the average transmittance T 45 0-600(50deg)AVE the absolute value of the difference therebetween is 5% or less (i-6) In the spectral transmittance curve at an incident angle of 0 degrees, the maximum transmittance T at wavelengths of 450 to 600 nm 450-600(0deg)MAX is 90% or more (i-7) In the spectral transmittance curve at an incident angle of 0 degrees, the wavelength IR50 at which the transmittance becomes 50% (0deg) is in the range of 610 to 650 nm (i-8) In the spectral transmittance curve at an incident angle of 50 degrees, the wavelength IR50 at which the transmittance becomes 50% (50deg) is in the range of 610 to 650 nm

Advantages of the Invention

[0009] According to the present invention, it is possible to provide an optical filter having little change in transmittance in the visible light region even at a high incident angle and excellent in transmittance in the visible light region and shielding property in the near infrared light region.

Brief Description of the Drawings

[0010] [Figure 1] FIG. 1 is a cross-sectional view schematically showing an example of an optical filter according to an embodiment. [[ID=3८]] [Figure 2] FIG. 2 is a cross-sectional view schematically showing another example of an optical filter according to an embodiment. [Figure 3] FIG. 3 is a cross-sectional view schematically showing another example of an optical filter according to an embodiment. [Figure 4] FIG. 4 is a diagram showing the spectral transmittance curve of a near-infrared absorbing glass. [Figure 5] FIG. 5 is a diagram showing the spectral transmittance curve of the resin film of Example 1-1. [Figure 6] FIG. 6 is a diagram showing the spectral transmittance curve of the substrate of Example 2-1. [Figure 7] FIG. 7 is a diagram showing the spectral transmittance curve of the optical filter of Example 4-1.

Mode for Carrying Out the Invention

[0011] 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.

[0012] In this specification, internal transmittance is defined by the formula {measured transmittance / (100-reflectance)}×100, which is the transmittance obtained by subtracting the effect of interfacial reflection from the measured transmittance. In this specification, the spectral transmission of a substrate and the transmission of a resin film, including cases where the dye is contained in the resin, are all referred to as "internal transmission" even when the term "transmission" is used. On the other hand, the transmission measured by dissolving the dye in a solvent such as dichloromethane, the transmission of a dielectric multilayer film, and the transmission of an optical filter having a dielectric multilayer film are measured transmissions.

[0013] In this specification, for a particular 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 particular 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 particular wavelength range are the arithmetic mean of the transmittance and internal transmittance for every 1 nm in that wavelength range. Optical properties can be measured using an ultraviolet-visible spectrophotometer. In this specification, the symbol "~" used to indicate a numerical range includes both upper and lower limits.

[0014] <Optical filters> An optical filter according to one embodiment of the present invention (hereinafter also referred to as "this filter") comprises a substrate and a dielectric multilayer film laminated as the outermost layer on at least one main surface side of the substrate. Here, the substrate comprises near-infrared absorbing glass and a resin film with a thickness of 10 μm or less laminated on at least one main surface of the near-infrared absorbing glass. Furthermore, the resin film contains a resin and a dye (NIR1) having a maximum absorption wavelength of 680 to 740 nm in the resin. The reflective properties of the dielectric multilayer film, combined with the absorption properties of the substrate containing near-infrared absorbing glass and near-infrared absorbing dye, enable the overall optical filter to achieve excellent transmittance in the visible light region and excellent shielding in the near-infrared light region.

[0015] An example of the configuration of this filter will be explained using the drawings. Figures 1 to 3 are schematic cross-sectional views showing an example of an optical filter according to one embodiment.

[0016] The optical filter 1A shown in Figure 1 is an example in which a dielectric multilayer film 20 is provided on one main surface side of a substrate 10 having near-infrared absorbing glass 11 and a resin film 12. Note that "having a specific layer on the main surface side of the substrate" is not limited to cases where the layer is in contact with the main surface of the substrate, but also includes cases where another functional layer is provided between the substrate and the layer. In the optical filter 1A of Figure 1, the dielectric multilayer film 20 is provided on the surface of the near-infrared absorbing glass 11, but it may also be provided on the surface of the resin film 12.

[0017] The optical filter 1B shown in Figure 2 is an example in which dielectric multilayer films 20A and 20B are located on both main surfaces of the substrate 10.

[0018] The optical filter 1C shown in Figure 3 is an example in which the substrate 10 has resin films 12A and 12B on both main surfaces of the near-infrared absorbing glass 11, and dielectric multilayer films 20A and 20B on both main surfaces of the substrate 10.

[0019] The optical filter of the present invention satisfies all of the following spectral characteristics (i-1) to (i-13). (i-1) In the spectral transmittance curve at an incident angle of 0 degrees, the average transmittance T for wavelengths of 450-600 nm 450-600(0deg)AVE over 80% (i-2) In the spectral transmittance curve at an incident angle of 50 degrees, the average transmittance T for wavelengths of 450-600 nm 450-600(50deg)AVE over 80% (i-3) The average transmittance T 450-600(0deg)AVE and the average transmittance T 450-600(50deg)AVE The absolute value of the difference is 5% or less. (i-4) In the spectral transmittance curve at an incident angle of 0 degrees, the transmittance T at a wavelength of 450 nm. 450(0deg) over 80% (i-5) In the spectral transmittance curve at an incident angle of 50 degrees, the transmittance T at a wavelength of 450 nm 450(50deg) over 80% (i-6) In the spectral transmittance curve at an incident angle of 0 degrees, the maximum transmittance T is observed at wavelengths of 450-600 nm. 450-600(0deg)MAX over 90% (i-7) In the spectral transmittance curve at an incident angle of 0 degrees, the wavelength at which the transmittance is 50% is IR50. (0deg) However, it is in the range of 610-650nm. (i-8) In the spectral transmittance curve at an incident angle of 50 degrees, the wavelength at which the transmittance is 50% is IR50. (50deg) However, it is in the range of 610-650nm. (i-9) The aforementioned wavelength IR50 (0deg) and the aforementioned wavelength IR50 (50deg) The absolute value of the difference is less than 10 nm. (i-10) In the spectral transmittance curve at an incident angle of 0 degrees, the maximum transmittance T at wavelengths of 1000 to 1200 nm. 1000-1200(0deg)MAX less than 5% (i-11) In the spectral transmittance curve at an incident angle of 50 degrees, the maximum transmittance T is observed at wavelengths of 1000 to 1200 nm. 1000-1200(50deg)MAX less than 5% (i-12) Said transmittance T 450(0deg) / The maximum transmittance T 1000-1200(0deg)MAX ≥25 (i-13) Said transmittance T 450(50deg) / The maximum transmittance T 1000-1200(50deg)MAX ≥10

[0020] This filter satisfies all of the spectral characteristics (i-1) to (i-13), and is an optical filter that exhibits minimal change in transmittance in the visible light region even at a high incidence angle of 50 degrees, and has excellent shielding properties in the near-infrared region.

[0021] Satisfying spectral characteristics (i-1) to (i-2) means that the transmittance in the visible light region of 450-600 nm is excellent even at high incidence angles, and satisfying spectral characteristic (i-3) means that the change in transmittance (ripple) in the visible light region of 450-600 nm is small even at high incidence angles. T 450-600(0deg)AVE This is preferably 85% or more, more preferably 87% or more. T 450-600(50deg)AVE The percentage is preferably 83% or more, and more preferably 85% or more. T 450-600(0deg)AVE and T 450-600(50deg)AVE The difference is preferably 4.5% or less, and more preferably 4% or less.

[0022] Satisfying spectral characteristics (i-4) to (i-5) means that the material exhibits excellent transmittance in the blue light region. T 450(0deg) This is preferably 82% or more, more preferably 85% or more. T 450(50deg) The percentage is preferably 81% or more, and more preferably 82% or more.

[0023] Satisfying the spectral characteristics (i-6) means that the lens exhibits excellent transmittance in the visible light region of 450-600 nm, even at high incidence angles. T 450-600(0deg)MAX The percentage is preferably 92% or more, and more preferably 93% or more.

[0024] Satisfying spectral characteristics (i-7) to (i-8) means that the near-infrared region can be blocked and visible transmitted light can be efficiently captured. IR50 (0deg) The wavelength is preferably 615-640 nm, more preferably 615-635 nm. IR50 (50deg)The wavelength is preferably 615-640 nm, more preferably 615-635 nm.

[0025] Satisfying spectral characteristics (i-9) means that the spectral curve in the 610-650 nm region is less likely to shift even at high incidence angles. The absolute value of the spectral characteristic (i-9) is preferably 9 nm or less, more preferably 8 nm or less.

[0026] Satisfying spectral characteristics (i-10) to (i-11) means that the lens exhibits excellent light shielding in the infrared region of 1000 to 1200 nm, even at high incidence angles. T 1000-1200(0deg)MAX The amount is preferably 4% or less, and more preferably 2% or less. T 1000-1200(50deg)MAX The amount is preferably 4% or less, and more preferably 3% or less.

[0027] Satisfying spectral characteristics (i-12) to (i-13) means that both transmittance in the visible light region and shielding in the infrared region are achieved even at high incidence angles. T 450(0deg) / T 1000-1200(0deg)MAX The value is preferably 30 or more, and more preferably 40 or more. T 450(50deg) / T 1000-1200(50deg)MAX The value is preferably 15 or more, more preferably 20 or more.

[0028] The optical filter of the present invention preferably further satisfies the following spectral characteristics (i-14) to (i-15). (i-14) In the spectral transmittance curve at an incident angle of 0 degrees, the maximum transmittance T is observed at wavelengths of 750 to 1000 nm. 750-1000(0deg)MAX less than 1% (i-15) In the spectral transmittance curve at an incident angle of 50 degrees, the maximum transmittance T is observed at wavelengths of 750 to 1000 nm. 750-1000(50deg)MAX less than 1%

[0029] Satisfying spectral characteristics (i-14) to (i-15) means that the lens exhibits excellent light-shielding properties in the near-infrared region of 750 to 1000 nm, even at high incidence angles. T 750-1000(0deg)MAX The amount is preferably 4% or less, and more preferably 2% or less. T 750-1000(50deg)MAX The amount is preferably 4% or less, and more preferably 3% or less.

[0030] The optical filter of the present invention preferably further satisfies the following spectral characteristics (i-16) to (i-18). (i-16) In the spectral transmittance curve at an incident angle of 0 degrees, the wavelength at which the transmittance is 50% is UV50. (0deg) However, it is in the range of 400-440nm. (i-17) In the spectral transmittance curve at an incident angle of 50 degrees, the wavelength at which the transmittance is 50% is UV50. (50deg) However, it is in the range of 400-440nm. (i-18) The aforementioned wavelength UV50 (0deg) and the aforementioned wavelength UV50 (50deg) The absolute value of the difference is less than 3 nm.

[0031] Satisfying spectral characteristics (i-16) to (i-17) means that the near-ultraviolet region can be blocked and visible transmitted light can be efficiently captured. Satisfying the spectral characteristics (i-18) means that the spectral curve in the 400-440 nm region is less likely to shift even at high incidence angles. UV50 (0deg) The wavelength is preferably 400-430 nm, more preferably 410-430 nm. UV50 (50deg) The wavelength is preferably 400-430 nm, more preferably 410-430 nm. The spectral characteristic (i-18) is preferably 2.5 nm or less, more preferably 2 nm or less.

[0032] The optical filter of the present invention preferably further satisfies the following spectral characteristics (i-19) to (i-22). (i-19) In the spectral transmittance curve at an incident angle of 0 degrees, the average transmittance T for wavelengths of 370-400 nm. 370-400(0deg)AVE less than 2% (i-20) In the spectral transmittance curve at an incident angle of 50 degrees, the average transmittance T for wavelengths of 370-400 nm 370-400(50deg)AVE less than 2% (i-21) In the spectral transmittance curve at an incident angle of 0 degrees, the maximum transmittance T is observed at wavelengths of 370-400 nm. 370-400(0deg)MAX less than 3% (i-22) In the spectral transmittance curve at an incident angle of 50 degrees, the maximum transmittance T is observed at wavelengths of 370-400 nm. 370-400(50deg)MAX less than 3%

[0033] Satisfying spectral characteristics (i-19) to (i-22) means that the lens exhibits excellent light-shielding properties in the near-ultraviolet region of 370-400 nm, even at high incidence angles. T 370-400(0deg)AVE The amount is preferably 1% or less, and more preferably 0.5% or less. T 370-400(50deg)AVE The amount is preferably 1% or less, and more preferably 0.5% or less. T 370-400(0deg)MAX The amount is preferably 2.5% or less, and more preferably 2% or less. T 370-400(50deg)MAX The amount is preferably 2.5% or less, and more preferably 2% or less.

[0034] <Dielectric multilayer film> In this filter, the dielectric multilayer film is laminated as the outermost layer on at least one main surface side of the substrate.

[0035] In this filter, it is preferable that the dielectric multilayer film satisfies all of the following spectral characteristics (v-1) to (v-5). (v-1) In the spectral transmittance curve at an incident angle of 0 degrees, the minimum transmittance T for wavelengths of 450-600 nm. 450-600(0deg)MIN over 90% (v-2) In the spectral transmittance curve at an incident angle of 50 degrees, the minimum transmittance T for wavelengths of 450-600 nm. 450-600(50deg)MIN over 90% (v-3)The minimum transmittance T 450-600(0deg)MIN and the minimum transmittance T 450-600(50deg)MIN The absolute value of the difference is 5% or less. (v-4) In the spectral transmittance curve at an incident angle of 0 degrees, the average transmittance T for wavelengths of 700 to 1200 nm. 700-1200(0deg)AVE 30-75% (v-5) In the spectral transmittance curve at an incident angle of 50 degrees, the average transmittance T for wavelengths of 700 to 1200 nm. 700-1200(50deg)AVE 30-75%

[0036] Satisfying spectral characteristics (v-4) to (v-5) means that the near-infrared region is gently shielded, and satisfying spectral characteristics (v-1) to (v-3) means that the change in transmittance (ripple) at high incidence angles in the visible light region is small. T 450-600(0deg)MIN The percentage is preferably 92% or more, and more preferably 93% or more. T 450-600(50deg)MIN Preferably, it is 90% or more, more preferably 90.5% or more. (v-3) is preferably 5% or less, more preferably 4% or less. T 700-1200(0deg)AVE The percentage is preferably 40% to 75%, more preferably 50% to 75%. T 700-1200(50deg)AVE The percentage is preferably 40% to 75%, more preferably 50% to 75%.

[0037] In this filter, it is preferable that the dielectric multilayer film further satisfies the following spectral characteristics (v-6) to (v-8). (v-6) In the spectral transmittance curve at an incident angle of 0 degrees, the average transmittance T for wavelengths of 450-600 nm. 450-600(0deg)AVE over 91% (v-7) In the spectral transmittance curve at an incident angle of 50 degrees, the average transmittance T for wavelengths of 450-600 nm 450-600(50deg)AVE over 91% (v-8) Average transmittance T 450-600(0deg)AVE and the average transmittance T 450-600(50deg)AVE The absolute value of the difference is 5% or less. Satisfying spectral characteristics (v-6) to (v-8) means that the lens exhibits excellent transmittance of visible light even at high incidence angles, and that the change in transmittance (ripple) with respect to variations in incidence angle is small. T 450-600(0deg)AVEThis is preferably 90% or more, and more preferably 92% or more. T 450-600(50deg)AVE This is preferably 90% or more, and more preferably 92% or more. (v-8) is preferably 4% or less, more preferably 3.5% or less.

[0038] In the present invention, it is preferable that the dielectric multilayer film gently shields the near-infrared region, as shown in the spectral characteristics (v-4) to (v-5) above. If the dielectric multilayer film is designed to enhance the reflection characteristics in the near-infrared region, ripple is likely to occur in the visible light region. In the present invention, by designing the dielectric multilayer film not to strongly shield the near-infrared region, ripple in the visible light region is suppressed, as shown in the spectral characteristics (v-1) to (v-3) above. The shielding of the near-infrared light region that cannot be completely shielded by the reflection characteristics of the dielectric multilayer film is complemented by the absorption characteristics of the substrate, which will be described later, and the present invention has excellent near-infrared shielding properties as an optical filter as a whole.

[0039] In this filter, it is preferable that at least one of the dielectric multilayer films is designed as a near-infrared reflective layer (hereinafter also referred to as the NIR reflective layer). The other dielectric multilayer film is preferably designed as an NIR reflective layer, a reflective layer having a reflection region other than the near-infrared region, or an anti-reflective layer.

[0040] An NIR reflective layer is a dielectric multilayer film designed to block light in the near-infrared region. For example, an NIR reflective layer may have wavelength selectivity that transmits visible light and primarily reflects light in the near-infrared region. The reflective region of the NIR reflective layer may also include the near-infrared light-blocking region of the resin film. The NIR reflective layer may be designed to further block light in wavelengths other than the near-infrared region, such as the near-ultraviolet region, as appropriate.

[0041] The NIR reflective layer is composed, for example, of a dielectric multilayer film in which dielectric films with different refractive indices are alternately stacked. Examples of dielectric films include low refractive index dielectric films (low refractive index films), medium refractive index dielectric films (medium refractive index films), and high refractive index dielectric films (high refractive index films). It is preferable to laminate two or more of these dielectric films in combination. In particular, it is preferable to have at least a medium refractive index film to enhance light shielding in the infrared region to the extent that ripple does not occur in the visible region.

[0042] The high refractive index film preferably has a refractive index of 2.2 or higher, and more preferably 2.2 to 2.5. Examples of materials for the high refractive index film include Ta2O5, TiO2, TiO, Ti2O3, 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.

[0043] The medium refractive index film preferably has a refractive index of 1.6 to 2.1. 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.

[0044] The low refractive index film preferably has a refractive index of 1.5 or less, and more preferably 1.4 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 AlO2) manufactured by Canon Optron. Of these, SiO2 is preferred in terms of reproducibility, stability, and cost-effectiveness in film formation.

[0045] To create a dielectric multilayer film that satisfies spectral characteristics (v-1) to (v-5), i.e., gentle light-shielding characteristics in the near-infrared region and low ripple characteristics in the visible light region, one can combine several dielectric films with different spectral characteristics when transmitting and selecting the desired wavelength band. Specifically, reflection ripple in the visible light region can be suppressed by reducing the refractive index difference between layers using materials for the medium-refractive-index layer and the low-refractive-index layer. Conventional infrared cut filters use low-refractive-index materials such as SiO2 / TiO2 and high-refractive-index materials to improve light-shielding in the near-infrared region, but this configuration tends to cause reflection ripple in the visible light region. In the optical filter configuration of the present invention, since the transmittance in the near-infrared region can be reduced by the absorption characteristics of the substrate (dye and absorbing glass), it is not necessarily required to use a low-refractive-index layer / high-refractive-index layer combination that tends to cause ripple in the visible light region.

[0046] The NIR reflective layer preferably has a total number of layers of dielectric multilayer films constituting the reflective layer: 20 or more, more preferably 30 or more, and even more preferably 35 or more. However, as the total number of layers increases, warping and other issues may occur, and the film thickness may increase; therefore, the total number of layers is preferably 100 or less, more preferably 75 or less, and even more preferably 60 or less. Furthermore, the thickness of the reflective layer is preferably 2 to 10 μm overall.

[0047] Furthermore, for the formation of 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.

[0048] The NIR reflective layer may provide predetermined optical properties with a single layer (a group of dielectric multilayer films) or with two layers. If there are two or more layers, each reflective layer may have the same or different configuration. When there are two or more reflective layers, they are usually composed of multiple reflective layers with different reflection bands. When two reflective layers are provided, one may be a near-infrared reflective layer that shields light in the short-wavelength band of the near-infrared region, and the other may be a near-infrared / near-ultraviolet reflective layer that shields light in both the long-wavelength band of the near-infrared region and the near-ultraviolet region.

[0049] Examples of anti-reflective layers include dielectric multilayer films, intermediate refractive index media, and moth-eye structures with gradually changing refractive indices. Among these, dielectric multilayer films are preferred from the viewpoint of optical efficiency and productivity. The anti-reflective layer is obtained by alternately stacking dielectric multilayer films, similar to the reflective layer.

[0050] <Base material> In the optical filter of the present invention, the substrate comprises near-infrared absorbing glass and a resin film with a thickness of 10 μm or less. The resin film comprises a resin and a dye (NIR1) having a maximum absorption wavelength of 680 to 740 nm in the resin, and is laminated on at least one main surface of the near-infrared absorbing glass.

[0051] <Spectral properties of the substrate> The substrate preferably satisfies all of the following spectral characteristics (ii-1) to (ii-7). (ii-1) Average internal transmittance T at wavelength 450~600nm 450-600AVE over 85% (ii-2) Maximum internal transmittance T at wavelengths of 450-600 nm 450-600MAX over 92% (ii-3) Internal transmittance T at a wavelength of 450 nm 450 over 82% (ii-4) The wavelength IR50 at which the internal transmittance is 50% is in the range of 610-650 nm. (ii-5) Average internal transmittance T at wavelength 750~1000nm 750-1000AVE less than 1.5% (ii-6) Maximum internal transmittance T at wavelengths of 1000-1200 nm 1000-1200MAX less than 5% (ii-7) Internal transmittance T 450 / Maximum internal transmittance T 1000-1200MAX ≥15

[0052] Satisfying spectral characteristics (ii-1) to (ii-2) means that the material exhibits excellent transmittance in the visible light region from 450 to 600 nm. T 450-600AVE The percentage is preferably 93% or more, and more preferably 95% or more. T 450-600MAXis preferably 87% or more, more preferably 88% or more.

[0053] By satisfying the spectral characteristic (ii-3), it means excellent transmittance in the blue light region. T 450 is preferably 83% or more, more preferably 84% or more.

[0054] By satisfying the spectral characteristic (ii-4), it means that the near-infrared region can be shielded and visible transmitted light can be efficiently captured. IR50 is preferably in the range of 615 to 640 nm, more preferably 615 to 635 nm.

[0055] By satisfying the spectral characteristic (ii-5), it means excellent light-shielding property in the near-infrared region of 750 to 1000 nm. T 750-1000AVE is preferably 1% or less, more preferably 0.8% or less.

[0056] By satisfying the spectral characteristic (ii-6), it means excellent light-shielding property in the infrared region of 1000 to 1200 nm. T 1000-1200MAX is preferably 4.8% or less, more preferably 4.5% or less.

[0057] By satisfying the spectral characteristic (ii-7), it means that the transmittance in the visible light region and the light-shielding property in the infrared region are compatible. Internal transmittance T 450 / Maximum internal transmittance T 1000-1200MAX is preferably 17 or more, more preferably 18 or more.

[0058] The substrate preferably further satisfies the following spectral characteristic (ii-8). (ii-8) Maximum internal transmittance T at wavelengths of 750 to 1000 nm 750-1000MAX is 2% or less By satisfying the spectral characteristic (ii-8), it means excellent light-shielding property in the near-infrared region of 750 to 1000 nm. T 750-1000MAXis preferably 1.2% or less, more preferably 0.8% or less.

[0059] The base material preferably further satisfies the following spectral characteristics (ii-9) to (ii-11). (ii-9) The wavelength UV50 at which the internal transmittance is 50% is in the range of 400 to 440 nm (ii-10) The average internal transmittance T at wavelengths of 370 to 400 nm 370-400AVE is 3% or less (ii-11) The maximum internal transmittance T at wavelengths of 370 to 400 nm 370-400MAX is 5% or less Satisfying the spectral characteristic (ii-9) means that the near-ultraviolet region can be shielded and visible transmitted light can be efficiently taken in. UV50 is preferably in the range of 400 to 430 nm, more preferably in the range of 410 to 430 nm. Satisfying the spectral characteristics (ii-10) to (ii-11) means excellent light-shielding properties in the near-ultraviolet region of 370 to 400 nm. T 370-400AVE is preferably 2% or less, more preferably 1% or less. T 370-400MAX is preferably 4.5% or less, more preferably 4% or less.

[0060] In the present invention, the base material has excellent light transmittance in the visible light region as shown in the above spectral characteristics (ii-1) to (ii-3), and excellent light-shielding properties in the near-infrared light region and the infrared light region as shown in the spectral characteristics (ii-5) to (ii-6), and as shown in the spectral characteristic (ii-7), it can achieve both the light transmittance and the light-shielding properties. In particular, the high light-shielding properties in the near-infrared light region and the infrared light region can complement the light-shielding properties of the dielectric multilayer film described above.

[0061] In the present invention, the base material has both the absorption ability of the near-infrared absorbing glass and the absorption ability of the resin film containing the near-infrared absorbing dye (NIR1).

[0062] <Near-infrared absorbing glass> The near-infrared absorbing glass preferably satisfies all of the following spectral characteristics (iii-1) to (iii-6). (iii-1) Average internal transmittance T at wavelength 450~600nm 450-600AVE over 90% (iii-2) Internal transmittance T at a wavelength of 450 nm 450 over 92% (iii-3) The wavelength IR50 at which the internal transmittance is 50% is in the range of 625-650 nm. (iii-4) Average internal transmittance T at wavelength 750~1000nm 750-1000AVE less than 2.5% (iii-5) Maximum internal transmittance T at wavelengths of 1000-1200 nm 1000-1200MAX less than 5% (iii-6) Internal transmittance T 450 / Maximum internal transmittance T 1000-1200MAX ≥10

[0063] Satisfying spectral characteristic (iii-1) means excellent transmittance in the visible light region of 450-600 nm, and satisfying spectral characteristic (iii-2) means excellent transmittance in the blue light region. T 450-600AVE The percentage is preferably 94% or more, and more preferably 95% or more. T 450 The percentage is preferably 83% or more, and more preferably 85% or more.

[0064] Satisfying spectral characteristics (iii-3) means that the near-infrared region can be blocked and visible transmitted light can be efficiently captured. IR50 is preferably in the range of 625 to 645 nm, more preferably 625 to 640 nm.

[0065] Satisfying spectral characteristics (iii-4) means that the material exhibits excellent light-shielding properties in the near-infrared region of 750-1000 nm. T 750-1000AVE The amount is preferably 2% or less, and more preferably 1.2% or less.

[0066] Satisfying spectral characteristics (iii-5) means that the material exhibits excellent light-shielding properties in the infrared region of 1000-1200 nm. T 1000-1200MAX The amount is preferably 4.8% or less, and more preferably 4.5% or less.

[0067] Satisfying spectral characteristics (iii-6) means that both transmittance in the visible light region and shielding in the infrared region are achieved. T 450 / T 1000-1200MAX The value is preferably 15 or more, more preferably 18 or more.

[0068] In the present invention, it is preferable that the near-infrared absorbing glass begins absorbing near-infrared light in the 625-650 nm region, as shown in characteristic (iii-3) above, and exhibits high light-shielding properties from 750 nm onward, as shown in characteristic (iii-4) above. This provides a substrate that can compensate for the light-shielding properties of the dielectric multilayer film described above.

[0069] The near-infrared absorbing glass is not limited to any glass that can obtain the above spectral characteristics, and examples include phthalate glass and phosphate glass that contain copper ions. Among these, phosphate glass is preferred from the viewpoint of easily obtaining the above spectral characteristics. Note that "phosphate glass" also includes silicate glass in which part of the glass skeleton is composed of SiO2.

[0070] For example, it is preferable that the phosphate-based glass contains the following glass components. The percentages of each glass component listed below are expressed as mass percent in terms of oxides. P2O5 is the main component (glass-forming oxide) that forms glass and is an essential component for enhancing near-infrared ray blocking. However, if the concentration is less than 65%, the effect is not sufficiently obtained, and if it exceeds 74%, the melting temperature rises and the transmittance in the visible range decreases, which is undesirable. Preferably, the concentration is 67-73%, and more preferably 68-72%. Al2O3 is an essential component for improving weather resistance, but its effect is not sufficiently obtained if it is less than 5%, and if it exceeds 10%, the melting temperature of the glass increases, reducing near-infrared cut properties and visible light transmittance, which is undesirable. Preferably, it is 6-10%, and more preferably 7-9%. B2O3 is an essential component for lowering the melting temperature of glass, but its effect is not sufficiently obtained if it is less than 0.5%, and it is undesirable if it exceeds 3% because the near-infrared blocking properties decrease. Preferably, it is 0.7 to 2.5%, and more preferably 0.8 to 2.0%. Although Li2O is not an essential component, it has the effect of lowering the melting temperature of the glass. However, it is undesirable if the amount exceeds 10% because the glass becomes unstable. Preferably, it is 0-5%, and more preferably 0-3%. Na2O is an essential component for lowering the melting temperature of glass, but its effect is not sufficiently obtained if it is less than 3%, and it is undesirable if it exceeds 10% because the glass becomes unstable. Preferably, it is 4-9%, and more preferably 5-9%. Li2O + Na2O is an essential component for lowering the melting temperature of glass, but its effect is insufficient at concentrations below 3%, and undesirable at concentrations above 15% because it makes the glass unstable. Preferably, the concentration is 4-13%, and more preferably 5-10%.

[0071] Although MgO is not an essential component, it does enhance the stability of the glass. However, concentrations exceeding 2% are undesirable because they reduce the near-infrared ray blocking properties. Preferably, the concentration is 1% or less, and it is even preferable that it is not present at all. Although CaO is not an essential component, it does enhance the stability of the glass. However, concentrations exceeding 2% are undesirable because they reduce the near-infrared ray blocking properties. Preferably, the concentration is 1.5% or less, and it is even preferable that it is not present at all. Although SrO is not an essential component, it has the effect of improving the stability of the glass, but it is undesirable if it exceeds 5% because it reduces the near-infrared ray blocking ability. Preferably, it is 0-4%, and more preferably 0-3%. BaO is an essential component for lowering the melting temperature of glass, but its effect is not sufficiently obtained if it is less than 3%, and it is undesirable if it exceeds 9% because the glass becomes unstable. Preferably, it is 3-8%, and more preferably 4-8%. MgO + CaO + SrO + BaO are essential components for increasing the stability of glass and lowering its melting temperature. However, concentrations below 3% are insufficient, while concentrations above 15% are undesirable as they make the glass unstable. Preferably, the concentration is 3-12%, and more preferably 4-10%.

[0072] CuO is an essential component for enhancing near-infrared blocking properties, but if it is less than 0.5%, the effect is not sufficiently obtained, and if it exceeds 20%, the visible range transmittance decreases, which is undesirable. Preferably, it is 1 to 15%, more preferably 2 to 10%, and most preferably 3 to 9%.

[0073] It is preferable that K2O is substantially absent from phosphate-based glasses. K2O is known to have the effect of lowering the melting temperature of glass. However, the inventors have confirmed that when both K2O and Na2O are included in phosphoric acid glass, the melting temperature of the glass is higher compared to when only Na2O is included and K2O is not. The reason for this is thought to be as follows: The liquidus temperature when P2O5 and Na2O are mixed in equimolars is approximately 628°C according to the phase diagram of a two-component system. In contrast, the liquidus temperature when P2O5 and K2O are mixed in equimolars exceeds 800°C according to the phase diagram of a two-component system. This suggests that when a portion of Na2O is replaced with K2O in phosphoric acid glass, the liquidus temperature tends to rise, and the melting temperature also rises. In this invention, "substantially absent" means not intentionally used as a raw material, and unavoidable impurities introduced from the raw material components or manufacturing process are considered substantially absent. Furthermore, considering the aforementioned unavoidable impurities, "substantially absent" means that the content is 0.05% or less.

[0074] In phosphate-based glasses, to obtain spectral characteristics with high visible-range transmittance and low near-infrared light transmittance, the copper ions in the glass component must be Cu, which absorbs in the ultraviolet region and is a factor that lowers visible-range transmittance. + Cu, which absorbs more in the near-infrared region 2+ It is important to have as many of them as possible. The copper in the glass component is reduced as the melting temperature of the glass increases, that is, Cu 2+ It is reduced to Cu + It tends to become that way. Therefore, Cu 2+ In order to increase the amount of [specific element] present, it is effective to keep the melting temperature of the glass as low as possible. The melting temperature of the near-infrared cut filter glass of the present invention is preferably 1150°C or lower, more preferably 1100°C or lower, and even more preferably 1080°C or lower. Therefore, the ratio of BaO and B2O3, which have the effect of lowering the melting temperature of glass, is increased compared to Al2O3, which has the effect of raising the melting temperature of glass. The balance of these glass components should be such that (BaO + B2O3) / Al2O3 is large, but if it is too large, it will lead to a decrease in weather resistance, so these ratios are in the range of 0.3 to 2.4. Furthermore, these ratios are preferably 0.3 to 2.0, and more preferably 0.5 to 1.5. In phosphate-based glasses, to obtain spectral characteristics with high visible-range transmittance and low near-infrared light transmittance, specifically a steep cutoff characteristic for light around 600-700 nm, the Cu in the glass is important. 2+ The distortion of the 6-coordinate structure is reduced, Cu 2+ Shifting the absorption peak to the longer wavelength side, that is, Cu in glass 2+ It is important to further enhance the absorption of near-infrared light by this method. Therefore, Cu in glass 2+ To reduce the distortion of the 6-coordinate structure, the number of non-crosslinked oxygen atoms in the glass is large, and the field strength of the modified oxide is high (field strength is the value obtained by dividing the valence Z by the square of the ionic radius r: Z / r 2 It was thought that the coefficient of attraction (which represents the degree to which the cation attracts oxygen) needed to be small. In order to increase the number of non-crosslinked oxygen atoms in glass, it is necessary to have a higher amount of P2O5 in the network oxides that form the glass network compared to other network oxides. Since P2O5 contains more oxygen in its molecule than Al2O3 and B2O3, Cu 2+ This makes it easier for non-crosslinked oxygen to coordinate, Cu 2+ The surrounding distortion is reduced. On the other hand, to improve the weather resistance of the glass, it is effective to increase the ratio of Al2O3 to P2O5, which affects weather resistance. Therefore, the balance of the network oxides contained in the glass is in the range of 6.5 to 10 for P2O5 / Al2O3. Furthermore, these ratios are preferably 7 to 10, and more preferably 7 to 9.5.

[0075] Furthermore, the smaller the field strength of the modified oxide in the glass, the smaller the wavenumber of the absorption peak becomes. 2+ It has been found that the absorption of light in the near-infrared region is increased. To achieve this, it is effective to include a larger amount of Na2O, which has a relatively low field strength, compared to other modified oxides. From this perspective, the balance of modified oxides contained in the glass should be such that a large Na2O / (Li2O+MgO+CaO+SrO+BaO) ratio is desirable. However, if it is too large, it will lead to a decrease in weather resistance, so these ratios should be in the range of 0.5 to 3. Furthermore, these ratios are preferably 0.5 to 2.5, and more preferably 0.7 to 2.

[0076] Furthermore, as near-infrared absorbing glass, chemically strengthened glass obtained by exchanging alkali metal ions with small ionic radii (e.g., Li ions, Na ions) present on the main surface of the glass plate with alkali ions with larger ionic radii (e.g., Na ions or K ions for Li ions, and K ions for Na ions) by ion exchange at a temperature below the glass transition temperature may be used.

[0077] The near-infrared absorbing glass preferably has a thickness of 0.5 mm or less, more preferably 0.3 mm or less, from the viewpoint of reducing the height of the camera module, and preferably 0.15 mm or more from the viewpoint of the element strength.

[0078] <Resin film> The resin film preferably satisfies all of the following spectral characteristics (iv-1) to (iv-5). (iv-1) The average internal transmittance T at wavelengths of 450 to 600 nm 450-600AVE is 93% or more (iv-2) The maximum internal transmittance T at wavelengths of 450 to 600 nm 450-600MAX is 95% or more (iv-3) The internal transmittance T at a wavelength of 450 nm 450 is 86% or more (iv-4) In the spectral transmittance curve at wavelengths of 650 to 900 nm, the shortest wavelength at which the internal transmittance becomes 50% is defined as IR50 (S) and the longest wavelength is defined as IR50 (L) When this is done, IR50 (L) -IR50 (S) ≧90 nm (iv-5) The minimum internal transmittance T at wavelengths of 700 to 800 nm 700-800MIN is 10% or less

[0079] Satisfying the spectral characteristics (iv-1) to (iv-2) means excellent transmittance in the visible light region of 450 to 600 nm. T 450-600AVE is preferably 94% or more, more preferably 95% or more. T 450-600MAX is preferably 96% or more, more preferably 97% or more.

[0080] Satisfying the spectral characteristic (iv-3) means excellent transmittance in the blue light region. T 450 is preferably 87% or more, more preferably 88% or more.

[0081] Satisfying spectral characteristics (iv-4) means that a wide range of near-infrared light in the vicinity of 700 nm can be blocked. IR50 (L) -IR50 (S) The wavelength is preferably 95 nm or greater, and more preferably 105 nm or greater.

[0082] Satisfying spectral characteristics (iv-5) means that the material exhibits excellent light-shielding properties in the near-infrared region of 700-800 nm. T 700-800MIN The percentage is preferably 9% or less, and more preferably 7% or less.

[0083] The resin film preferably further satisfies the following spectral characteristics (iv-6) to (iv-7). (iv-6) Wavelength IR50 at which internal transmittance is 50% (S) However, it is in the range of 650-700nm. (iv-7) Wavelength IR50 at which internal transmittance is 50% (L) However, it is in the range of 740-850nm. Satisfying spectral characteristics (iv-6) to (iv-7) means that the near-infrared light region around 700 nm can be efficiently blocked. IR50 (S) The wavelength is preferably 650-690 nm, more preferably 660-690 nm. IR50 (L) The wavelength is preferably 750-830 nm, more preferably 760-830 nm.

[0084] The resin film preferably further satisfies the following spectral characteristics (iv-8). (iv-8) Average internal transmittance T at wavelength 700~800nm 700-800AVE less than 30% Satisfying the spectral characteristics (iv-8) means that it has excellent light-shielding properties in the near-infrared region of 700-800 nm. T 700-800AVE Preferably, it is 2.8% or less, more preferably 2.5% or less.

[0085] The resin film preferably further satisfies the following spectral characteristics (iv-9) to (iv-11). (iv-9) The wavelength UV50 at which the internal transmittance is 50% is in the range of 400-440 nm. (iv-10) Average internal transmittance T at wavelength 370~400nm 370-400AVE less than 3% (iv-11) Maximum internal transmittance T at wavelengths of 370-400 nm 370-400MAX less than 5% Satisfying spectral characteristics (iv-9) to (iv-11) means that the material exhibits excellent light-shielding properties in the near-ultraviolet region of 370 to 400 nm. UV50 is preferably in the range of 400 to 430 nm, more preferably 410 to 430 nm. T 370-400AVE The amount is preferably 2% or less, and more preferably 1% or less. T 370-400MAX Preferably, it is 4.8% or less, more preferably 4.6% or less.

[0086] The resin film in this invention contains a dye (NIR1) having a maximum absorption wavelength of 680-740 nm, and as shown in the above characteristics (iv-4) and (iv-5), it exhibits particularly excellent broad light-shielding properties in the near-infrared region around 700 nm. This allows the near-infrared region around 700 nm, where infrared absorbing glass exhibits somewhat weak light-shielding properties, to be shielded by the absorption characteristics of the dye.

[0087] The dye (NIR1) has a maximum absorption wavelength in the resin between 680 and 740 nm, preferably between 700 and 730 nm. Here, "resin" refers to the resin that constitutes the resin film. The NIR dye may consist of one compound or may contain two or more compounds. Here, the resin film in the present invention preferably further contains other near-infrared absorbing dyes having different maximum absorption wavelengths in addition to the dye (NIR1). Thereby, the resin film can obtain a wide light-shielding property in the near-infrared light region around 700 nm, and the characteristic (iv-4) is easily obtained. As the other near-infrared absorbing dye, a dye (NIR2) having a maximum absorption wavelength in the resin 20 to 60 nm larger than that of the dye (NIR1) is preferable. Further, the maximum absorption wavelength of the dye (NIR2) is preferably 700 to 800 nm.

[0088] As the dye (NIR1), a squarylium compound is preferable from the viewpoints of the region of the maximum absorption wavelength, the transmittance in the visible light region, the solubility in the resin, and the durability. The maximum absorption wavelength of the squarylium compound as the dye (NIR1) is preferably 680 to 740 nm. As the dye (NIR2), a squarylium compound and a cyanine compound are preferable from the viewpoints of the region of the maximum absorption wavelength, the transmittance in the visible light region, the solubility in the resin, and the durability. The maximum absorption wavelength of the squarylium compound as the dye (NIR2) is preferably 740 to 770 nm. The maximum absorption wavelength of the cyanine compound as the dye (NIR2) is preferably 740 to 800 nm.

[0089] <NIR1: Squarylium compound> The squarylium compound as the dye (NIR1) is preferably a compound represented by the following formula (I). When the same symbol exists in two or more in the squarylium compound, those symbols may be the same or different. The same applies to the cyanine compound.

[0090] <Squarylium compound (I)>

[0091]

Chemical formula

[0092] However, the symbols in the above formula are as follows. R 24 And R 26Each of these independently consists of a hydrogen atom, a halogen atom, a hydroxyl group, a C1-C20 alkyl or alkoxy group, a C1-C10 acyloxy group, a C6-C11 aryl group, a C7-C18 alaryl group which may have substituents and may have oxygen atoms between carbon atoms, and -NR 27 R 28 (R 27 and R 28 These are, independently, a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, and -C(=O)-R 29 (R 29 (This may include hydrogen atoms, halogen atoms, hydroxyl groups, hydrocarbon groups having 1 to 25 carbon atoms that may have substituents, unsaturated bonds between carbon atoms, oxygen atoms, or saturated or unsaturated ring structures), -NHR 30 , or -SO2-R 30 (R 30 (R) represents a hydrocarbon group having 1 to 25 carbon atoms, in which each hydrogen atom may be substituted with a halogen atom, hydroxyl group, carboxyl group, sulfo group, or cyano group, and which may contain unsaturated bonds, oxygen atoms, or saturated or unsaturated ring structures between carbon atoms. ) or a group represented by the following formula (S) (R) 41 , R 42 k independently represents a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 10 carbon atoms. k is 2 or 3.

[0093] [ka]

[0094] R 21 and R 22 , R 22 and R 25 , and R 21 and R 23 These may be linked together to form heterocycles A, B, and C, respectively, with nitrogen atoms, each having a membership of 5 or 6. R when a heteroalgebra A is formed 21 and R 22This represents an alkylene group or alkylene oxy group in which the hydrogen atom may be substituted with an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an acyloxy group having 1 to 10 carbon atoms that may have substituents, as the divalent group -Q- to which these are bonded. R when a heteroalgebra B is formed 22 and R 25 , and R when a heterocyclic ring C is formed 21 and R 23 These are the divalent groups -X to which they are bonded. 1 -Y 1 -and -X 2 -Y 2 -(The side that bonds to nitrogen is X) 1 and X 2 ) as X 1 and X 2 These are the groups represented by the following formulas (1x) or (2x), and Y 1 and Y 2 Each of these is a group represented by one of the following formulas (1y) to (5y). 1 and X 2 However, in the case of the base represented by the following formula (2x), Y 1 and Y 2 Each of these may be a single bond, in which case there may be an oxygen atom between the carbon atoms.

[0095] [ka]

[0096] In formula (1x), the four Zs are each independently a hydrogen atom, a hydroxyl group, an alkyl or alkoxy group having 1 to 6 carbon atoms, or -NR 38 R 39 (R 38 and R 39 Each of these independently represents either a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. 31 ~R 36 Each independently comprises a hydrogen atom, a C1-C6 alkyl group, or a C6-C10 aryl group, R 37This represents an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms. R 27 , R 28 , R 29 , R 31 ~R 37 , R when it does not form a heteroalgebra 21 ~R 23 , and R 25 These may bond with any of the others to form a five-membered ring or a six-membered ring. 31 and R 36 , R 31 and R 37 They may be directly joined. When R does not form a heteroalgebra, 21 , R 22 , R 23 and R 25 Each of these independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a C1-C20 alkyl or alkoxy group, a C1-C10 acyloxy group, a C6-C11 aryl group, or a C7-C18 alaryl group which may have substituents or oxygen atoms between carbon atoms.

[0097] Examples of compound (I) include compounds represented by any of formulas (I-1) to (I-3), and from the viewpoint of solubility in the resin, heat resistance and light resistance in the resin, and visible light transmittance of the resin layer containing it, the compound represented by formula (I-1) is particularly preferred.

[0098] [ka]

[0099] The symbols in formulas (I-1) to (I-3) are the same as those specified for the same symbols in formula (I), and the preferred embodiments are also the same.

[0100] In compound (I-1), X 1 As for the base, (2x) is preferred, Y 1 A single bond or group (1y) is preferred. In this case, R 31 ~R36 Preferably, it is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom or a methyl group. 1 -X 1 Specifically, examples include the divalent organic groups shown in formulas (11-1) to (12-3).

[0101] -C(CH3)2-CH(CH3)- …(11-1) -C(CH3)2-CH2- …(11-2) -C(CH3)2-CH(C2H5)- …(11-3) -C(CH3)2-C(CH3)(nC3H7)- …(11-4) -C(CH3)2-CH2-CH2- …(12-1) -C(CH3)2-CH2-CH(CH3)- …(12-2) -C(CH3)2-CH(CH3)-CH2- …(12-3)

[0102] Furthermore, in compound (I-1), R 21 From the viewpoint of solubility, heat resistance, and the steepness of the change near the boundary between the visible and near-infrared regions in the spectral transmittance curve, the group represented by formula (4-1) or (4-2) is independently more preferred.

[0103] [ka]

[0104] In equations (4-1) and (4-2), R 71 ~R 75 This independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms.

[0105] In compound (I-1), R 24 -NR 27 R 28 Preferably. -NR 27 R 28 From the perspective of solubility in resins and coating solvents, -NH-C(=O)-R 29 or -NH-SO2-R30 It is preferable.

[0106] In compound (I-1), R 24 -NH-C(=O)-R 29 The compound is shown in formula (I-11).

[0107] [ka]

[0108] R 23 and R 26 These are preferably, independently, a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 6 carbon atoms, with a hydrogen atom being more preferred in any case.

[0109] R 29 Preferred substituents include C1-C20 alkyl groups which may have substituents, C6-C10 aryl groups which may have substituents, or C7-C18 alaryl groups which may have substituents and may have oxygen atoms between carbon atoms. Examples of substituents include hydroxyl groups, carboxyl groups, sulfo groups, cyano groups, C1-C6 alkyl groups, C1-C6 fluoroalkyl groups, C1-C6 alkoxy groups, and C1-C6 acyloxy groups.

[0110] R 29 Preferably, the group is selected from linear, branched, or cyclic alkyl groups having 1 to 17 carbon atoms, phenyl groups which may be substituted with alkoxy groups having 1 to 6 carbon atoms, and alaryl groups having 7 to 18 carbon atoms which may have oxygen atoms between carbon atoms.

[0111] R 29 As an example, groups that are hydrocarbon groups having 5 to 25 carbon atoms and having at least one branch may also be used, in which one or more hydrogen atoms may be independently substituted with a hydroxyl group, a carboxyl group, a sulfo group, or a cyano group, and which may contain unsaturated bonds, oxygen atoms, or saturated or unsaturated ring structures between carbon atoms.

[0112] As the compound (I-11), more specifically, the compounds shown in the following table can be mentioned. In addition, for the compounds shown in the following table, the meanings of the respective symbols are the same on the left and right of the squarylium skeleton.

[0113]

Table 1

[0114] As the compound (I-11), among these, compounds (1-11-1) to (1-11-12), compounds (1-11-17) to (1-11-28) are preferable from the viewpoints of solubility in resin, maximum absorption wavelength, light resistance, heat resistance, and high absorbance. In particular, compounds (1-11-1) to (1-11-12) are preferable from the viewpoints of light resistance and heat resistance. Since the light shielding property in the ultraviolet region by the dielectric multilayer film in the configuration of the present invention is gentle, the light resistance of the dye is particularly important.

[0115] <着 <NIR2: Squarylium compound> The squarylium compound which is the dye (NIR2) is preferably a compound represented by the following formula (II).

[0116] <Squarylium compound (II)>

[0117]

Chemical formula

[0118] However, the symbols in the above formula are as follows. Ring Z is each independently a 5-membered ring or a 6-membered ring having 0 to 3 heteroatoms in the ring, and the hydrogen atoms possessed by ring Z may be substituted. R 1 and R 2 、R 2 and R 3 、and R 1The carbon atoms or heteroatoms constituting ring Z may be linked to each other and form heterorings A1, B1, and C1, respectively, together with the nitrogen atom, in which case the hydrogen atoms in heterorings A1, B1, and C1 may be substituted. 1 and R 2 Each of these independently represents a hydrocarbon group which may contain an unsaturated bond, heteroatom, saturated or unsaturated ring structure between a hydrogen atom, a halogen atom, or carbon atoms, and which may have substituents. 4 and R when it does not form a heterocycle 3 Each of these independently represents an alkyl or alkoxy group which may contain a hydrogen atom, a halogen atom, or a heteroatom between carbon atoms, and which may have substituents.

[0119] Examples of compound (II) include compounds represented by any of formulas (II-1) to (II-3), and from the viewpoint of solubility in the resin and visible light transmittance in the resin, the compound represented by formula (II-3) is particularly preferred.

[0120] [ka]

[0121] In formula (II-1) and formula (II-2), R 1 and R 2 Each of these independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 15 carbon atoms which may have substituents, and R 3 ~R 6 Each of these independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms, which may have substituents.

[0122] In formula (II-3), R 1 , R 4 , and R 9 ~R 12 Each of these independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 15 carbon atoms which may have substituents, and R 7 and R8 Each of these independently represents a hydrogen atom, a halogen atom, or a C1-C5 alkyl group which may have substituents.

[0123] R in compound (II-1) and compound (II-2) 1 and R 2 From the viewpoint of solubility in resin, visible light transmittance, etc., an alkyl group having 1 to 15 carbon atoms is preferred, and an alkyl group having 7 to 15 carbon atoms is more preferred, R 1 and R 2 At least one of them is more preferably an alkyl group having a branched chain with 7 to 15 carbon atoms, R 1 and R 2 Alkyl groups having branched chains with 8 to 15 carbon atoms are particularly preferred for both.

[0124] R in compound (II-3) 1 From the viewpoint of solubility in transparent resins and visible light transmittance, alkyl groups having 1 to 15 carbon atoms are preferred, alkyl groups having 1 to 10 carbon atoms are more preferred, and ethyl groups and isopropyl groups are particularly preferred.

[0125] R 4 From the viewpoint of visible light transmittance and ease of synthesis, hydrogen atoms and halogen atoms are preferred, with hydrogen atoms being particularly preferred. R 7 and R 8 The following are preferred independently: a hydrogen atom, a halogen atom, and a C1-C5 alkyl group which may be substituted with a halogen atom; a hydrogen atom, a halogen atom, and a methyl group are more preferred.

[0126] R 9 ~R 12 The following are preferred independently: a hydrogen atom, a halogen atom, and a C1-C5 alkyl group which may be substituted with a halogen atom. -CR 9 R 10 -CR 11 R 12 -Examples include the divalent organic groups represented by the following groups (13-1) to (13-5). -CH(CH3)-C(CH3)2- …(13-1) -C(CH3)2-CH(CH3)- …(13-2) -C(CH3)2-CH2- …(13-3) -C(CH3)2-CH(C2H5)- …(13-4) -CH(CH3)-C(CH3)(CH2-CH(CH3)2)-…(13-5)

[0127] More specifically, examples of the compound (II-3) include the compounds shown in the following table. In addition, for the compounds shown in the following table, the meanings of the respective symbols are the same on the left and right of the squarylium skeleton.

[0128]

Table 2

[0129] Among these, as the compound (II-3), compounds (II-3-1) to compounds (II-3-4) are preferable from the viewpoints of solubility in resin, high absorption coefficient, light resistance, and heat resistance.

[0130] The compounds (I) to (II) can each be produced by a known method. For the compound (I), it can be produced by the methods described in U.S. Patent No. 5,543,086, U.S. Patent Application Publication No. 2014 / 0061505, and International Publication No. 2014 / 088063. For the compound (II), it can be produced by the method described in International Publication No. 2017 / 135359.

[0131] <NIR2: Cyanine compound> The cyanine compound that is the dye (NIR2) is preferably a compound represented by the following formula (III).

[0132]

Chemical formula

[0133] However, the symbols in the above formula are as follows: R 101 ~R 109 Each of these independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 15 carbon atoms which may have substituents, or an aryl group having 5 to 20 carbon atoms. 110 ~R 114 These independently represent a hydrogen atom, a halogen atom, and an alkyl group having 1 to 15 carbon atoms. X - This indicates a monovalent anion. n1 is either 0 or 1. -(CH2) n1 The hydrogen atom bonded to the carbon ring containing - may be substituted with a halogen atom, a C1-C15 alkyl group which may have substituents, or a C5-C20 aryl group.

[0134] In the above, the alkyl group (including the alkyl group of the alkoxy group) may be linear, branched, or saturated. The aryl group is a group that is bonded via carbon atoms constituting the aromatic ring of an aromatic compound, such as a benzene ring, naphthalene ring, biphenyl, furan ring, thiophene ring, pyrrole ring, etc. Substituents in C1-C15 alkyl or alkoxy groups, or C5-C20 aryl groups, which may have substituents, include halogen atoms and C1-C10 alkoxy groups.

[0135] In equation (III), R 101 The alkyl group is preferably a C1-C15 alkyl group or a C5-C20 aryl group, and a branched C1-C15 alkyl group is more preferred from the viewpoint of maintaining high visible light transmittance in the resin.

[0136] In equation (III), R 102 ~R 105 , R 108 , R 109 Each of these is preferably an independent hydrogen atom, an alkyl or alkoxy group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms, with hydrogen atoms being more preferred from the viewpoint of obtaining high visible light transmittance.

[0137] In equation (III), R 110 ~R 114 Each of these is preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms, with hydrogen atoms being more preferred from the viewpoint of obtaining high visible light transmittance.

[0138] R 106 , R 107 Each of these is preferably a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms (which may include linear, cyclic, or branched alkyl groups), and more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. 106 and R 107 The same group is preferable.

[0139] X - As for, I - BF4 - PF6 - ClO4 - Examples include anions represented by formulas (X1) and (X2), preferably BF4 - , or PF6 - That is the case.

[0140] [ka]

[0141] In the following explanation, in pigment (III), R 101 ~R 114 The part excluding this is also called the skeleton (III).

[0142] In equation (III), compounds with n1 = 1 are shown in equation (III-1) below, and compounds with n1 = 0 are shown in equation (III-2) below.

[0143] [ka]

[0144] In equations (III-1) and (III-2), R101 ~R 114 and X - This is the same as in the case of equation (III). R 115 ~R 120 Each of these independently represents a hydrogen atom, a halogen atom, an alkyl or alkoxy group having 1 to 15 carbon atoms which may have substituents, or an aryl group having 5 to 20 carbon atoms. 115 ~R 120 Each of these is preferably a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms (which may include linear, cyclic, or branched alkyl groups), and more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. 115 ~R 120 It is preferable that they be the same group.

[0145] More specifically, the compounds represented by formulas (III-1) and (III-2) are compounds in which the atoms or groups bonded to each skeleton are those shown in the table below. In all the compounds shown in the table below, R 101 ~R 109 The terms on both sides of the equation are identical.

[0146] R in the table below 110 -R 114 The symbol indicates the atom or group bonded to the central benzene ring in each formula, and "H" is written when all five are hydrogen atoms. 110 -R 114 If one of the atoms is a substituent and the others are hydrogen atoms, only the combination of the sign of the substituent and the substituent is listed. For example, "R 112 The description "-C(CH3)3" is R 112 This indicates that one element is -C(CH3)3, and the others are hydrogen atoms.

[0147] R in the table below 115 -R 120 R indicates the atom or group bonded to the central cyclohexane ring in formula (III-1), and is denoted as "H" if all six are hydrogen atoms. 115 -R 120In the case where any one of them is a substituent and the rest are hydrogen atoms, only the combination of the symbol that is the substituent and the substituent is described.

[0148]

Table 3

[0149] Among these, as the dye (III-1), from the viewpoints of transparency in the visible light region, solubility in the resin, heat resistance, and light resistance, dyes (III-1-1) to (III-1-12) etc. are preferable. Particularly, dyes (III-1-1), (III-1-5), and (III-1-9) are particularly preferable in terms of ease of synthesis.

[0150] The dye (III) can be produced, for example, by the methods described in Dyes and pigments 73(2007) 344-352 and J.Heterocyclic chem,42,959(2005).

[0151] The content of the NIR dye in the resin film is preferably 0.1 to 25 parts by mass, more preferably 0.3 to 15 parts by mass, based on 100 parts by mass of the resin. In the case of combining two or more compounds, the above content is the sum of each compound. Also, when the dyes (NIR1) and (NIR2) are used in combination, the content of the dye (NIR1) is preferably 0.1 to 10 parts by mass based on 100 parts by mass of the resin, and the content of the dye (NIR2) is preferably 0.1 to 10 parts by mass based on 100 parts by mass of the resin.

[0152] <UV Dye> In addition to the above NIR dye, the resin film may contain other dyes. As the other dye, a dye (UV) having a maximum absorption wavelength at 370 to 440 nm in the resin is preferable. Thereby, the near ultraviolet region can be efficiently shielded.

[0153] Examples of UV 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.

[0154] As the dye (UV), merocyanine dyes represented by the following formula (M) are particularly preferred.

[0155] [ka]

[0156] The symbols in equation (M) are as follows:

[0157] R 1 This represents a monovalent hydrocarbon group having 1 to 12 carbon atoms, which may have substituents. Preferred substituents are alkoxy groups, acyl groups, acyloxy groups, cyano groups, dialkylamino groups, or chlorine atoms. The number of carbon atoms in the alkoxy groups, acyl groups, acyloxy groups, and dialkylamino groups is preferably 1 to 6.

[0158] R without substituents 1 Specifically, preferred are C1-C12 alkyl groups in which some of the hydrogen atoms may be substituted with an aliphatic ring, an aromatic ring, or an alkenyl group, C3-C8 cycloalkyl groups in which some of the hydrogen atoms may be substituted with an aromatic ring, an alkyl group, or an alkenyl group, and C6-C12 aryl groups in which some of the hydrogen atoms may be substituted with an aliphatic ring, an alkyl group, or an alkenyl group.

[0159] R 1 If the alkyl group is an unsubstituted alkyl group, it may be linear or branched, and its carbon number is more preferably 1 to 6.

[0160] R1 When the alkyl group has 1 to 12 carbon atoms, some of the hydrogen atoms are substituted with an aliphatic ring, an aromatic ring, or an alkenyl group, alkyl groups with 1 to 4 carbon atoms having a cycloalkyl group with 3 to 6 carbon atoms, alkyl groups with 1 to 4 carbon atoms substituted with a phenyl group are more preferred, and alkyl groups with 1 or 2 carbon atoms substituted with a phenyl group are particularly preferred. An alkyl group substituted with an alkenyl group means an alkenyl group as a whole, but without an unsaturated bond between the 1st and 2nd positions, such as an allyl group or a 3-butenyl group.

[0161] Preferred R 1 R is a C1-C6 alkyl group in which some of the hydrogen atoms may be substituted with cycloalkyl groups or phenyl groups. Particularly preferred R 1 This refers to an alkyl group having 1 to 6 carbon atoms, specifically including methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and t-butyl groups.

[0162] R 2 ~R 5 Each of these independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms. The alkyl group and alkoxy group preferably have 1 to 6 carbon atoms, and more preferably 1 to 4 carbon atoms.

[0163] R 2 and R 3 Preferably, at least one of them is an alkyl group, and more preferably, both are alkyl groups. 2 and R 3 If it is not an alkyl group, a hydrogen atom is more preferable. 2 and R 3 Alkyl alkyl groups having 1 to 6 carbon atoms are particularly preferred.

[0164] R 4 and R 5 At least one of them is preferably a hydrogen atom, and both are more preferably hydrogen atoms. 4 or R 5If it is not a hydrogen atom, an alkyl group having 1 to 6 carbon atoms is preferred.

[0165] Y is R 6 and R 7 This represents a methylene group or oxygen atom substituted with [a specific component]. R 6 and R 7 Each of these independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms.

[0166] X represents one of the divalent groups shown in the following formulas (X1) to (X5).

[0167] [ka]

[0168] R 8 and R 9 Each of these independently represents a monovalent hydrocarbon group having 1 to 12 carbon atoms, which may have substituents, and R 10 ~R 19 Each of these independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms, which may have substituents. R 8 ~R 19 As substituents, R 1 Examples of substituents similar to those in R include similar substituents, and preferred embodiments are also similar. 8 ~R 19 If is a hydrocarbon group without substituents, then R without substituents 1 Similar embodiments can be cited.

[0169] In equation (X1), R 8 and R 9 The groups may be different, but the same group is preferred. 8 and R 9 When is an unsubstituted alkyl group, it may be linear or branched, and the number of carbon atoms is more preferably 1 to 6.

[0170] Preferred R8 and R 9 These are all C1-C6 alkyl groups in which some of the hydrogen atoms may be substituted with cycloalkyl groups or phenyl groups. Particularly preferred R 8 and R 9 These are all alkyl groups having 1 to 6 carbon atoms, and specifically, examples include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, etc.

[0171] In equation (X2), R 10 and R 11 In all cases, alkyl groups having 1 to 6 carbon atoms are more preferred, and the same alkyl group is particularly preferred.

[0172] In equation (X3), R 12 and R 15 Preferably, these are hydrogen atoms or unsubstituted alkyl groups having 1 to 6 carbon atoms. R is two groups bonded to the same carbon atom. 13 and R 14 These are preferably hydrogen atoms or alkyl groups having 1 to 6 carbon atoms.

[0173] In formula (X4), the two groups R bonded to the same carbon atom 16 and R 17 and R 18 and R 19 These are preferably hydrogen atoms or alkyl groups having 1 to 6 carbon atoms.

[0174] Compound (M) can be prepared by known methods.

[0175] The pigment (UV) content in the resin film is preferably 0.1 to 15 parts by mass, more preferably 1 to 10 parts by mass, per 100 parts by mass of resin. Within this range, a decrease in resin properties is unlikely.

[0176] <Base material composition> The substrate in this filter is a composite substrate in which a resin film is laminated on at least one main surface of near-infrared absorbing glass.

[0177] 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.

[0178] When multiple compounds are used as NIR dyes or other dyes, they may be contained in the same resin film, or they may each be contained in separate resin films.

[0179] 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.

[0180] 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.

[0181] Furthermore, the resin film can also be manufactured in film form by extrusion molding. The resulting film-like resin film can be laminated onto near-infrared absorbing glass and integrated by thermocompression bonding or the like to produce a substrate.

[0182] 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 or different configuration.

[0183] 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.

[0184] The shape of the substrate is not particularly limited and may be in the form of a block, plate, or film.

[0185] This filter may also include other components, such as a component (layer) that provides absorption by inorganic nanoparticles that control the transmission and absorption of light in a specific wavelength range. Specific examples of inorganic nanoparticles include ITO (Indium Tin Oxides), ATO (Antimony-doped Tin Oxides), cesium tungstate, and lanthanum boride. ITO nanoparticles and cesium tungstate nanoparticles 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.

[0186] As described above, the following optical filters and the like are disclosed in this specification. [1] An optical filter comprising a substrate and a dielectric multilayer film laminated as the outermost layer on at least one main surface side of the substrate, The substrate comprises near-infrared absorbing glass and a resin film with a thickness of 10 μm or less laminated on at least one main surface of the near-infrared absorbing glass. The resin film comprises a resin and a dye (NIR1) having a maximum absorption wavelength of 680 to 740 nm in the resin. The optical filter is an optical filter that satisfies all of the following spectral characteristics (i-1) to (i-13). (i-1) In the spectral transmittance curve at an incident angle of 0 degrees, the average transmittance T for wavelengths of 450-600 nm 450-600(0deg)AVE over 80% (i-2) In the spectral transmittance curve at an incident angle of 50 degrees, the average transmittance T for wavelengths of 450-600 nm 450-600(50deg)AVE over 80% (i-3) The average transmittance T 450-600(0deg)AVE and the average transmittance T 450-600(50deg)AVE The absolute value of the difference is 5% or less. (i-4) In the spectral transmittance curve at an incident angle of 0 degrees, the transmittance T at a wavelength of 450 nm. 450(0deg) over 80% (i-5) In the spectral transmittance curve at an incident angle of 50 degrees, the transmittance T at a wavelength of 450 nm 450(50deg) over 80% (i-6) In the spectral transmittance curve at an incident angle of 0 degrees, the maximum transmittance T is observed at wavelengths of 450-600 nm. 450-600(0deg)MAX over 90% (i-7) In the spectral transmittance curve at an incident angle of 0 degrees, the wavelength at which the transmittance is 50% is IR50. (0deg) However, it is in the range of 610-650nm. (i-8) In the spectral transmittance curve at an incident angle of 50 degrees, the wavelength at which the transmittance is 50% is IR50. (50deg) However, it is in the range of 610-650nm. (i-9) The aforementioned wavelength IR50 (0deg) and the aforementioned wavelength IR50 (50deg) The absolute value of the difference is less than 10 nm. (i-10) In the spectral transmittance curve at an incident angle of 0 degrees, the maximum transmittance T at wavelengths of 1000 to 1200 nm. 1000-1200(0deg)MAX less than 5% (i-11) In the spectral transmittance curve at an incident angle of 50 degrees, the maximum transmittance T is observed at wavelengths of 1000 to 1200 nm. 1000-1200(50deg)MAX less than 5% (i-12) Said transmittance T 450(0deg) / The maximum transmittance T1000-1200(0deg)MAX ≥25 (i-13) Said transmittance T 450(50deg) / The maximum transmittance T 1000-1200(50deg)MAX ≥10 [2] The optical filter according to [1], wherein the optical filter further satisfies the following spectral characteristics (i-14) to (i-15). (i-14) In the spectral transmittance curve at an incident angle of 0 degrees, the maximum transmittance T is observed at wavelengths of 750 to 1000 nm. 750-1000(0deg)MAX less than 1% (i-15) In the spectral transmittance curve at an incident angle of 50 degrees, the maximum transmittance T is observed at wavelengths of 750 to 1000 nm. 750-1000(50deg)MAX less than 1% [3] The optical filter according to [1] or [2], wherein the substrate satisfies all of the following spectral characteristics (ii-1) to (ii-7). (ii-1) Average internal transmittance T at wavelength 450~600nm 450-600AVE over 85% (ii-2) Maximum internal transmittance T at wavelengths of 450-600 nm 450-600MAX over 92% (ii-3) Internal transmittance T at a wavelength of 450 nm 450 over 82% (ii-4) The wavelength IR50 at which the internal transmittance is 50% is in the range of 610-650 nm. (ii-5) Average internal transmittance T at wavelength 750~1000nm 750-1000AVE less than 1.5% (ii-6) Maximum internal transmittance T at wavelengths of 1000-1200 nm 1000-1200MAX less than 5% (ii-7) Internal transmittance T 450 / Maximum internal transmittance T 1000-1200MAX ≥15 [4] The optical filter according to any one of [1] to [3], wherein the substrate further satisfies the following spectral characteristics (ii-8). (ii-8) Maximum internal transmittance T at wavelengths of 750-1000 nm 750-1000MAX less than 2% [5] An optical filter according to any one of [1] to [4], wherein the near-infrared absorbing glass satisfies all of the following spectral characteristics (iii-1) to (iii-6). (iii-1) Average internal transmittance T at wavelength 450~600nm 450-600AVE over 90% (iii-2) Internal transmittance T at a wavelength of 450 nm 450 over 92% (iii-3) The wavelength IR50 at which the internal transmittance is 50% is in the range of 625-650 nm. (iii-4) Average internal transmittance T at wavelength 750~1000nm 750-1000AVE less than 2.5% (iii-5) Maximum internal transmittance T at wavelengths of 1000-1200 nm 1000-1200MAX less than 5% (iii-6) Internal transmittance T 450 / Maximum internal transmittance T 1000-1200MAX ≥10 [6] The optical filter according to any one of [1] to [5], wherein the resin film satisfies all of the following spectral characteristics (iv-1) to (iv-5). (iv-1) Average internal transmittance T at wavelength 450~600nm 450-600AVE over 93% (iv-2) Maximum internal transmittance T at wavelengths of 450-600 nm 450-600MAX over 95% (iv-3) Internal transmittance T at a wavelength of 450 nm 450 over 86% (iv-4) The shortest wavelength at which the internal transmittance is 50% in the spectral transmittance curve for wavelengths of 650-900 nm is defined as IR50. (S) The longest wavelength is IR50 (L) In that case, IR50 (L) -IR50 (S) ≥90nm (iv-5) Minimum internal transmittance T at wavelengths of 700-800 nm 700-800MIN less than 10% [7] The resin film further contains a dye (NIR2), The optical filter according to any one of [1] to [6], wherein the dye (NIR2) has a maximum absorption wavelength in the resin that is 20 to 60 nm greater than the maximum absorption wavelength of the dye (NIR1) in the resin. [8] An optical filter according to any one of [1] to [7], wherein the dielectric multilayer film satisfies all of the following spectral characteristics (v-1) to (v-5). (v-1) In the spectral transmittance curve at an incident angle of 0 degrees, the minimum transmittance T for wavelengths of 450-600 nm. 450-600(0deg)MIN over 90% (v-2) In the spectral transmittance curve at an incident angle of 50 degrees, the minimum transmittance T for wavelengths of 450-600 nm. 450-600(50deg)MIN over 90% (v-3)The minimum transmittance T 450-600(0deg)MIN and the minimum transmittance T 450-600(50deg)MIN The absolute value of the difference is 5% or less. (v-4) In the spectral transmittance curve at an incident angle of 0 degrees, the average transmittance T for wavelengths of 700 to 1200 nm. 700-1200(0deg)AVE 30-75% (v-5) In the spectral transmittance curve at an incident angle of 50 degrees, the average transmittance T for wavelengths of 700 to 1200 nm. 700-1200(50deg)AVE 30-75% [9] The optical filter according to any one of [1] to [8], wherein the dielectric multilayer film includes a dielectric thin film having a refractive index of 1.6 to 2.1.

[10] The resin film contains a squarylium compound as a dye (NIR1) having a maximum absorption wavelength of 680 to 740 nm in the resin. The optical filter according to any one of [1] to [9], further comprising at least one of a squarylium compound and a cyanine compound as a dye (NIR2) whose maximum absorption wavelength in the resin is 20 to 60 nm greater than the maximum absorption wavelength of the dye (NIR1) in the resin.

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

[10] , wherein the resin film further comprises a dye (UV) having a maximum absorption wavelength of 370 to 440 nm in the resin. An imaging device equipped with an optical filter as described in any of

[12] , [1], to

[11] . [Examples]

[0187] Next, the present invention will be described in more detail with reference to examples. A UV-Vis spectrophotometer (Hitachi High-Technologies Corporation, UH-4150 model) 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° (perpendicular to the main surface of the optical filter).

[0188] The dyes used in each example are as follows: Compound 1 (squallium compound): Synthesized based on International Publication No. 2014 / 088063 and International Publication No. 2016 / 133099. Compound 2 (merocyanine compound): Synthesized according to German Patent Publication No. 10109243. Compound 3 (squallium compound): Synthesized according to International Publication No. 2017 / 135359. Compound 4 (cyanine compound): Synthesized according to the method described in Dyes and Pigments, 73, 344-352 (2007). Compound 5 (cyanine compound): Synthesized according to the method described in Dyes and Pigments, 73, 344-352 (2007). Compound 6 (diimmonium compound): Synthesized according to the method described in Japanese Patent Publication No. 4800769.

[0189] [ka]

[0190] <Spectral properties of pigments in resin> A polyimide resin solution with a resin concentration of 8.5% by mass was prepared by dissolving polyimide resin (product name "C3G30G" manufactured by Mitsubishi Gas Chemical Company, Inc., refractive index 1.59) in a γ-butyrolactone (GBL):cyclohexanone ratio of 1:1 (by mass). Each of the above compounds 1 to 6 was added to the resin solution at a concentration of 7.5 parts by mass per 100 parts by mass of resin, and the mixture was stirred and dissolved at 50°C for 2 hours to obtain a coating solution. The obtained coating solution was applied to alkali glass (SCHOTT, D263 glass, 0.2 mm thick) by spin coating, forming coating films with a thickness of approximately 1.0 μm. The spectral transmittance curves of the obtained coating films were measured in the wavelength range of 350 to 1200 nm using an ultraviolet-visible spectrophotometer. The spectral properties of each of the compounds 1 to 6 above in polyimide resin are shown in the table below. Note that the spectral properties shown in the table below were evaluated using internal transmittance to avoid the influence of reflection at the air interface and glass interface.

[0191] [Table 4]

[0192] <Spectral characteristics of near-infrared absorbing glass> As near-infrared absorbing glass, we prepared phosphate glass (AGC Corporation, SP50T). For near-infrared absorbing glass, spectral transmittance curves were measured in the wavelength range of 350 to 1200 nm using a UV-Vis spectrophotometer. From the obtained spectral characteristics data, the average internal transmittance T at wavelengths of 450-600 nm was determined. 450-600AVE , maximum internal transmittance T 450-600MAX Internal transmittance T at a wavelength of 450 nm 450 The wavelength IR50, where the internal transmittance is 50%, and the average internal transmittance T for wavelengths of 750-1000nm. 750-1000AVE Maximum internal transmittance T at wavelengths of 1000-1200 nm 1000-1200MAX , internal transmittance T 450 / Maximum internal transmittance T 1000-1200MAX , was calculated. The results are shown in the table below. Note that the spectral characteristics shown in the table below were evaluated using internal transmittance to avoid the influence of reflection at the air interface and glass interface. Furthermore, the spectral transmission curve of the near-infrared absorbing glass is shown in Figure 4.

[0193] [Table 5]

[0194] As shown above, the near-infrared absorbing glass used has high transmittance in the visible light region and excellent light-blocking properties in the near-infrared region.

[0195] <Examples 1-1 to 1-5: Spectral characteristics of resin films> One of the dyes from compounds 1 to 6 was mixed at the concentrations shown in the table below into a polyimide resin solution prepared in the same manner as when the spectral characteristics of the above compounds were calculated. The mixture was then stirred and dissolved at 50°C for 2 hours to obtain a coating solution. The obtained coating solution was applied to alkali glass (SCHOTT, D263 glass, 0.2 mm thick) by spin coating to form a resin film with a thickness of 3.0 μm. The spectral transmittance curves of the obtained resin film were measured in the wavelength range of 350 to 1200 nm using an ultraviolet-visible spectrophotometer. From the obtained spectral characteristics data, the average internal transmittance T at wavelengths of 450-600 nm was determined. 450-600AVE , maximum internal transmittance T 450-600MAX Internal transmittance T at a wavelength of 450 nm 450 , the shortest wavelength IR50 in which the internal transmittance is 50% in the spectral transmittance curve for wavelengths of 650-900 nm (S) and the longest wavelength IR50 (L) The difference between this and the average internal transmittance T at wavelengths of 700-800nm. 700-800AVE , minimum internal transmittance T 700-800MIN The wavelength at which the internal transmittance is 50% is UV50, and the average internal transmittance for wavelengths of 370-400nm is T 370-400AVE , maximum internal transmittance T 370-400MAX The result was calculated. The results are shown in the table below. Note that the spectral characteristics shown in the table below were evaluated using internal transmittance to avoid the influence of reflection at the air interface and glass interface. Furthermore, the spectral transmittance curve of the resin film in Example 1-1 is shown in Figure 5. Examples 1-1 to 1-5 are for reference only.

[0196] [Table 6]

[0197] <Examples 2-1 to 2-5: Spectral characteristics of the substrate> One of the dyes from compounds 1 to 6 was mixed at the concentrations shown in the table below into a polyimide resin solution prepared in the same manner as when the spectral characteristics of the above compounds were calculated. The mixture was then stirred and dissolved at 50°C for 2 hours to obtain a coating solution. The obtained coating solution was applied to a near-infrared absorbing glass (AGC, SP50T) with a thickness of 0.28 nm by spin coating to form a resin film with a thickness of 3.0 μm. The spectral transmittance curves of the obtained resin film were measured in the wavelength range of 350 to 1200 nm using an ultraviolet-visible spectrophotometer. From the obtained spectral characteristics data, the average internal transmittance T at wavelengths of 450-600 nm was determined. 450-600AVE , maximum internal transmittance T 450-600MAX Internal transmittance T at a wavelength of 450 nm 450 The wavelength IR50, where the internal transmittance is 50%, and the average internal transmittance T for wavelengths of 750-1000nm. 750-1000AVE , maximum internal transmittance T 750-1000MAX Maximum internal transmittance T at wavelengths of 1000-1200 nm 1000-1200MAX , internal transmittance T 450 / Maximum internal transmittance T 1000-1200MAX The wavelength at which the internal transmittance is 50% is UV50, and the average internal transmittance for wavelengths of 370-400nm is T 370-400AVE , was calculated. The results are shown in the table below. Note that the spectral characteristics shown in the table below were evaluated using internal transmittance to avoid the influence of reflection at the air interface and glass interface. Furthermore, the spectral transmittance curve of the substrate in Example 2-1 is shown in Figure 6. Examples 2-1 to 2-5 are for reference only.

[0198] [Table 7]

[0199] From the above results, it can be seen that by combining glass with excellent near-infrared absorption and visible light transmittance with a dye that deeply absorbs light around 700-800 nm and has high visible light transmittance, the spectral characteristics of the optical filter can be almost guaranteed by the absorption characteristics of the substrate alone. In particular, the substrate in this invention has a ratio of visible light transmittance to near-infrared light transmittance (T 450 / T 1000-1200MAX Due to its high (brightness) properties, it achieves both visible light transmission and near-infrared shielding.

[0200] <Examples 3-1 to 3-4: Spectroscopic properties of dielectric multilayer films> On the surface of alkali glass (SCHOTT, D263 glass, 0.2 mm thick), two materials from the high refractive index, medium refractive index, and low refractive index materials shown in the table below were alternately layered by vapor deposition to form a dielectric monolayer film of the thickness shown in the table below. For the obtained dielectric monolayer films, spectral transmittance curves were measured using an ultraviolet-visible spectrophotometer at incident angles of 0 degrees and 50 degrees in the wavelength range of 350 to 1200 nm. From the obtained spectral characteristics data, the minimum transmittance T at an incident angle of 0 degrees in the wavelength range of 450-600 nm was determined. 450-600(0deg)MIN Minimum transmittance T at an incident angle of 50 degrees 450-600(50deg)MIN , minimum transmittance T 450-600(0deg)MIN and minimum transmittance T 450-600(50deg)MIN The difference between this and the average transmittance T at an incident angle of 0 degrees in wavelengths of 450-600 nm. 450-600(0deg)AVE , average transmittance T at an incident angle of 50 degrees 450-600(50deg)AVE , average transmittance T 450-600(0deg)AVE and average transmittance T 450-600(50deg)AVE The difference between this and the average transmittance T at an incident angle of 0 degrees in wavelengths of 700-1200 nm. 700-1200(0deg)AVE , average transmittance T at an incident angle of 50 degrees 700-1200(50deg)AVE , was calculated. The results are shown in the table below. Examples 3-1 to 3-4 are for reference only.

[0201] [Table 8]

[0202] From the above results, it can be seen that the transmittance is high in the 450-600 nm range at incident angles of 0 and 50 degrees, and that the transmittance does not change easily, meaning that it is a multilayer film with high transmittance in the visible light region and low ripple generation. In addition, the transmittance in the 700-1200 nm range indicates that the near-infrared light region is gently blocked.

[0203] <Examples 4-1 to 4-9: Spectral characteristics of optical filters> For optical films comprising a substrate with one of the configurations in Examples 2-1 to 2-5 and a dielectric multilayer film (reflective film) with one of the configurations in Examples 3-1 to 3-4, spectral transmittance curves were measured at incident angles of 0 and 50 degrees in the wavelength range of 350 to 1200 nm using an ultraviolet-visible spectrophotometer. The optical filter consisted of a resin film, near-infrared absorbing glass, and a reflective film. From the obtained spectral characteristics data, the average transmittance T at an incident angle of 0 degrees in the wavelength range of 450-600 nm was obtained. 450-600(0deg)AVE , average transmittance T at an incident angle of 50 degrees 450-600(50deg)AVE , average transmittance T 450-600(0deg)AVE and average transmittance T 450-600(50deg)AVE The difference between this and the transmittance T at an incident angle of 0 degrees at a wavelength of 450 nm. 450(0deg) Transmittance T at an incident angle of 50 degrees 450(50deg) , Maximum transmittance T at an incident angle of 0 degrees in wavelengths of 450-600 nm 450-600(0deg)MAX , wavelength IR50 where the transmittance is 50% at an incident angle of 0 degrees (0deg) , wavelength IR50 where the transmittance is 50% at an incident angle of 50 degrees (50deg) , wavelength IR50 (0deg) and wavelength IR50 (50deg) The absolute value of the difference between and , the maximum transmittance T at an incident angle of 0 degrees in wavelengths of 1000-1200 nm. 1000-1200(0deg)MAX Maximum transmittance T at an incident angle of 50 degrees 1000-1200(50deg)MAX , transmittance T 450(0deg) / Maximum transmittance T 1000-1200(0deg)MAX , transmittance T 450(50deg) / Maximum transmittance T 1000-1200(50deg)MAX , UV50 wavelength at which transmittance is 50% at an incident angle of 0 degrees (0deg) At an incident angle of 50 degrees, the transmittance is 50% at the wavelength UV50. (50deg) , wavelength UV50 (0deg)and wavelength UV50 (50deg) The absolute value of the difference between [value] and [value], the average transmittance T at an incident angle of 0 degrees for wavelengths of 370-400 nm. 370-400(0deg)AVE , average transmittance T at an incident angle of 50 degrees 370-400(50deg)AVE , Maximum transmittance T at an incident angle of 0 degrees in wavelengths of 750-1000 nm 750-1000(0deg)MAX Maximum transmittance T at an incident angle of 50 degrees 750-1000(50deg)MAX , Maximum transmittance T at an incident angle of 0 degrees in wavelengths of 370-400 nm 370-400(0deg)MAX Maximum transmittance T at an incident angle of 50 degrees 370-400(50deg)MAX , was calculated. The results are shown in the table below. Furthermore, the spectral transmittance curve of the optical filter in Example 4-1 is shown in Figure 7. Examples 4-1 to 4-3, 4-5, 4-6, and 4-9 are examples, while examples 4-4, 4-7, and 4-8 are comparative examples.

[0204] [Table 9]

[0205] From the results above, it can be seen that the optical filters in Examples 4-1 to 4-3, 4-5, 4-6, and 4-9 exhibit minimal ripple generation in the visible light region even at high incidence angles, and demonstrate excellent transmittance in the visible light region and light shielding in the near-infrared region from 700 to 1200 nm. The optical filter in Example 4-4 has an average transmittance T 450-600(0deg)AVE and average transmittance T 450-600(50deg)AVE The difference is large, and the change in visible light transmittance is large at high incident angles. In Example 4-4, the transmittance T at a wavelength of 450 nm at an incident angle of 50 degrees is 450(50deg) The average transmittance T for wavelengths of 450-600nm 450-600(50deg)AVE The noise level is also low. The dielectric multilayer film used in Example 4-4 exhibits excellent light shielding in the near-infrared region, but it is thought that ripples tend to occur in the visible light region at high incidence angles. The optical filters in Examples 4-7 and 4-8 have a transmittance T at an incident angle of 50 degrees at a wavelength of 450 nm. 450(50deg) It can be seen that the value is low. Also, the maximum transmittance T at an incident angle of 0 degrees in the wavelength range of 450-600 nm 450-600(0deg)MAXThe maximum absorption wavelength is also low. In Examples 4-7 and 4-8, the maximum absorption wavelength of the dye compound used in combination with compound 1, which has a maximum absorption wavelength of 722 nm, is 845 nm in Example 4-7 (using compound 5) and 1112 nm in Example 4-8 (using compound 6). Generally, the longer the maximum absorption wavelength, the lower the transmittance in the visible light region tends to be; therefore, it is thought that the transmittance in the visible light region decreased in Examples 4-7 and 4-8.

[0206] 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. 2021-113057, filed on July 7, 2021, the contents of which are incorporated herein by reference. [Industrial applicability]

[0207] The optical filter of the present invention has excellent visible light transmittance, minimal change in transmittance in the visible light region even at high incidence angles, and excellent spectral characteristics in shielding the near-infrared light region. It is useful in applications such as imaging devices like cameras and sensors for transport aircraft, where performance has been steadily improving in recent years. [Explanation of symbols]

[0208] 1A, 1B, 1C…Optical filters, 10…Substrate, 11…Near-infrared absorbing glass, 12, 12A, 12B…Resin film, 20, 20A, 20B…Dielectric multilayer film

Claims

1. An optical filter comprising a substrate, a dielectric multilayer film 1 on one main surface side of the substrate, and a dielectric multilayer film 2 on the other main surface side of the substrate, The substrate comprises near-infrared absorbing glass and at least one layer of resin film. The resin film has a total thickness of 10 μm or less, and the at least one layer of the resin film comprises a resin and a dye (NIR1). The optical filter satisfies all of the following spectral characteristics (i-1) to (i-3), (i-6) to (i-8), and (i-18) to (i-20), In the spectral transmittance curve at an incident angle of 0 degrees, the maximum transmittance T is observed at wavelengths of 750 to 1000 nm. ７５０－１０００（０ｄｅｇ）ＭＡＸ The percentage is 2.6% or less. In the spectral transmittance curve at an incident angle of 50 degrees, the maximum transmittance T is observed at wavelengths of 750 to 1000 nm. ７５０－１０００（５０ｄｅｇ）ＭＡＸ An optical filter with a viscosity of 3% or less. (i-1) In the spectral transmittance curve at an incident angle of 0 degrees, the average transmittance T for wavelengths of 450 to 600 nm. ４５０－６００（０ｄｅｇ）ＡＶＥ over 80% (i-2) In the spectral transmittance curve at an incident angle of 50 degrees, the average transmittance T for wavelengths of 450 to 600 nm. ４５０－６００（５０ｄｅｇ）ＡＶＥ over 80% (i-3) The average transmittance T ４５０－６００（０ｄｅｇ）ＡＶＥ and the average transmittance T ４５０－６００（５０ｄｅｇ）ＡＶＥ The absolute value of the difference is 5% or less. (i-6) In the spectral transmittance curve at an incident angle of 0 degrees, the maximum transmittance T is observed at wavelengths of 450-600 nm. ４５０－６００（０ｄｅｇ）ＭＡＸ over 90% (i-7) In the spectral transmittance curve at an incident angle of 0 degrees, the wavelength at which the transmittance is 50% is IR50. （０ｄｅｇ） However, it is in the range of 610-650 nm. (i-8) In the spectral transmittance curve at an incident angle of 50 degrees, the wavelength IR50 at which the transmittance becomes 50% （５０ｄｅｇ） is in the range of 610 to 650 nm (i-18) In the spectral transmittance curve at an incident angle of 0 degrees, the wavelength UV50 is such that the transmittance is 50%. （０ｄｅｇ） And in the spectral transmittance curve at an incident angle of 50 degrees, the wavelength UV50 where the transmittance is 50% （５０ｄｅｇ） The absolute value of the difference is 3 nm or less. (i-19) In the spectral transmittance curve at an incident angle of 0 degrees, the average transmittance T 370-400 (0 deg) AVE for wavelengths of 370-400 nm is 2% or less. (i-20) In the spectral transmittance curve at an incident angle of 50 degrees, the average transmittance T 370-400 (50 deg) AVE for wavelengths of 370-400 nm is 2% or less.

2. In the spectral characteristics (i-6), the maximum transmittance T at wavelengths of 450 to 600 nm is ４５０－６００（０ｄｅｇ）ＭＡＸ The optical filter according to claim 1, wherein the ratio is 93% or more.

3. The maximum transmittance T at wavelengths of 750 to 1000 nm ７５０－１０００（５０ｄｅｇ）ＭＡＸ The optical filter according to claim 1, wherein the content is 2.1% or less.

4. The optical filter according to claim 1, wherein the optical filter further satisfies the following spectral characteristics (i-4) to (i-5). (i-4) In the spectral transmittance curve at an incident angle of 0 degrees, the transmittance T at a wavelength of 450 nm. ４５０（０ｄｅｇ） over 80% (i-5) In the spectral transmittance curve at an incident angle of 50 degrees, the transmittance T at a wavelength of 450 nm. ４５０（５０ｄｅｇ） over 80%

5. In the spectral transmittance curve at an incident angle of 0 degrees, the transmittance T at a wavelength of 450 nm is shown. ４５０（０ｄｅｇ） The optical filter according to claim 1, wherein the ratio is 85% or more.

6. The optical filter according to claim 1, wherein the average transmittance in the spectral transmittance curve at an incident angle of 0 degrees is 0.4% or less in the wavelength range of 700 to 1000 nm.

7. The optical filter according to claim 1, wherein the average transmittance in the wavelength range of 700 to 1000 nm in the spectral transmittance curve at an incident angle of 50 degrees is 0.2% or less.

8. The optical filter according to claim 1, wherein the near-infrared absorbing glass satisfies the following spectral characteristics (iii-1) and (iii-2). (iii-1) Average internal transmittance T for wavelengths of 450 to 600 nm ４５０－６００ＡＶＥ over 90% (iii-2) Internal transmittance T at a wavelength of 450 nm ４５０ over 92%

9. The optical filter according to claim 1, wherein the near-infrared absorbing glass satisfies the following spectral characteristics (iii-3) and (iii-4). (iii-3) The wavelength IR50 at which the internal transmittance is 50% is in the range of 625-650 nm. (iii-4) Average internal transmittance T for wavelengths of 750 to 1000 nm ７５０－１０００ＡＶＥ less than 2.5%

10. The optical filter according to claim 1, wherein the near-infrared absorbing glass satisfies the following spectral characteristics (iii-5) and (iii-6). (iii-5) Maximum internal transmittance T at wavelengths of 1000-1200 nm １０００－１２００ＭＡＸ less than 5% (ii-6) Internal Transmittance T ４５０ / Maximum internal transmittance T １０００－１２００ＭＡＸ ≥10

11. The optical filter according to claim 1, wherein the resin film satisfies all of the following spectral characteristics (iv-1) to (iv-3). (iv-1) Average internal transmittance T for wavelengths of 450 to 600 nm ４５０－６００ＡＶＥ over 93% (iv-2) Maximum internal transmittance T at wavelengths of 450-600 nm ４５０－６００ＭＡＸ over 95% (iv-3) Internal transmittance T at a wavelength of 450 nm ４５０ over 86%

12. The optical filter according to claim 1, wherein the resin film satisfies all of the following spectral characteristics (iv-4) to (iv-5). (iv-4) The shortest wavelength at which the internal transmittance is 50% in the spectral transmittance curve for wavelengths of 650-900 nm is IR50. （Ｓ） The longest wavelength is IR50 （Ｌ） In that case, IR50 （Ｌ） -IR50 （Ｓ） ≧90nm (iv-5) Minimum internal transmittance T at wavelengths of 700-800 nm ７００－８００ＭＩＮ less than 10%

13. The resin film contains, as the dye (NIR1), a squarylium compound having a maximum absorption wavelength of 680 to 740 nm in the resin. The optical filter according to claim 1, further comprising at least one of a squarylium compound and a cyanine compound as a dye (NIR2) whose maximum absorption wavelength in the resin is 20 to 60 nm greater than the maximum absorption wavelength of the dye (NIR1) in the resin.

14. The optical filter according to claim 1, wherein the number of layers of the resin film is one or two.

15. An imaging apparatus comprising an optical filter according to any one of claims 1 to 14.

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