Optical filter

Abstract

The present invention relates to an optical filter having a dielectric multilayer film (1), a glass substrate, a dielectric multilayer film (2), a light absorbing layer, and a dielectric multilayer film (3) in this order, the light absorbing layer containing a near-infrared absorbing dye, and the optical filter satisfying all spectral characteristics (i-1) to (i-6).

Description

Technical Field

[0001] The present invention relates to a filter. Background Art

[0002] For imaging devices using solid-state imaging elements, their applications have been extended to devices such as surveillance cameras and in-vehicle cameras that perform imaging day and night. In such devices, it is necessary to separately obtain (color) images based on visible light and (black-and-white) images based on infrared light.

[0003] Therefore, research is being conducted on filters, so-called dual-bandpass filters, which in addition to having a function of a near-infrared cut-off filter that allows visible light to pass through and faithfully reproduces an image based on the visible light, also have a function of selectively allowing specific near-infrared light to pass through.

[0004] Patent Document 1 describes a filter obtained by combining a dielectric multilayer film and a resin substrate containing a near-infrared absorbing pigment, which allows visible light and near-infrared light around 850 nm to pass through and shields light other than that.

[0005] Patent Document 2 describes a filter obtained by combining a dielectric multilayer film and a resin substrate containing a near-infrared absorbing pigment, which allows visible light and near-infrared light around 940 nm to pass through and shields light other than that.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: International Publication No. 2017 / 030174

[0009] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2016-200771 Summary of the Invention

[0010] Problems to be Solved by the Invention

[0011] In recent years, with the diversification of the sensing regions in the imaging field, lasers in a part of the near-infrared light region of 1000 nm or more, having a wavelength range different from those in Patent Document 1 and Patent Document 2, are used. Therefore, a filter is required that can allow the near-infrared light in this sensing region to pass through and can shield near-infrared light and near-ultraviolet light other than that, which become noise.

[0012] In addition, for a filter having a dielectric multilayer film, the optical film thickness of the dielectric multilayer film varies according to the incident angle of light, and thus there is a problem of variation in the spectral transmittance curve caused by the incident angle. For example, when the incident angle of light becomes larger, the reflection characteristics shift toward the short-wavelength side, and as a result, in a region where shielding is originally desired, the reflection characteristics may decrease. The larger the incident angle, the more strongly this phenomenon occurs. When such a filter is used, the spectral sensitivity of a solid-state imaging device may be affected by the incident angle. With the recent trend of reducing the height of camera modules, it is envisaged to use them under high incident angle conditions, and thus a filter that is not easily affected by the incident angle is required.

[0013] An object of the present invention is to provide a filter that has excellent shielding properties for specific near-infrared light and near-ultraviolet light other than visible light and specific near-infrared light that become transmission regions even at high incident angles.

[0014] Means for Solving the Problem

[0015] The present invention relates to a filter and the like having the following configuration.

[0016] A filter that sequentially has a dielectric multilayer film (1), a glass substrate, a dielectric multilayer film (2), a light absorption layer, and a dielectric multilayer film (3), wherein

[0017] the light absorption layer contains a near-infrared absorbing dye,

[0018] the filter satisfies all of the following spectral characteristics (i-1) to (i-6):

[0019] (i-1) When one main surface is taken as the incident direction, the average reflectance of light having a wavelength of 1300 nm to 1500 nm is 90% or more at an incident angle of 5 degrees and 90% or more at an incident angle of 40 degrees;

[0020] (i-2) When one main surface is taken as the incident direction, the maximum reflectance of light having a wavelength of 1300 nm to 1500 nm is 95% or more at an incident angle of 5 degrees and 95% or more at an incident angle of 40 degrees;

[0021] (i-3) When the other main surface is taken as the incident direction, the average reflectance of light having a wavelength of 750 nm to 900 nm is 30% or more at an incident angle of 5 degrees and 30% or more at an incident angle of 40 degrees;

[0022] (i-4) When the other main surface is taken as the incident direction, the maximum reflectance of light having a wavelength of 750 nm to 900 nm is 80% or more at an incident angle of 5 degrees and 70% or more at an incident angle of 40 degrees;

[0023] (i-5) The average transmittance of light with a wavelength of 350 nm to 400 nm is 1% or less at an incident angle of 0 degrees and 2% or less at an incident angle of 40 degrees;

[0024] (i-6) The maximum transmittance of light with a wavelength of 350 nm to 400 nm is 2% or less at an incident angle of 0 degrees and 3% or less at an incident angle of 40 degrees.

[0025] Advantages of the Invention

[0026] According to the present invention, it is possible to provide a filter having excellent shielding properties for specific near-infrared light and near-ultraviolet light other than visible light and specific near-infrared light that become the transmission region even at a high incident angle. The filter of the present invention is a filter having excellent reflection characteristics for light with a wavelength of 1300 nm to 1500 nm and light with a wavelength of 750 nm to 900 nm that become noise and excellent shielding properties for near-ultraviolet light, and is not easily affected by the incident angle. Description of the Drawings

[0027] Figure 1 It is a cross-sectional view schematically showing an example of a filter of an embodiment.

[0028] Figure 2 It is a graph showing the spectral transmittance curve of glass.

[0029] Figure 3 It is a graph showing the spectral transmittance curve of the light absorption layer.

[0030] Figure 4 It is a graph showing the spectral transmittance curve of the filter of Example 1.

[0031] Figure 5 It is a graph showing the spectral reflectance curve of the filter of Example 1.

[0032] Figure 6 It is a graph showing the spectral reflectance curve of the filter of Example 1.

[0033] Figure 7 It is a graph showing the spectral transmittance curve of the filter of Example 5.

[0034] Figure 8 It is a graph showing the spectral reflectance curve of the filter of Example 5.

[0035] Figure 9 It is a graph showing the spectral reflectance curve of the filter of Example 5.

[0036] Explanation of Reference Numerals

[0037] 1 Dielectric multilayer film

[0038] 2 Dielectric multilayer film

[0039] 3-Medium Multilayer Film

[0040] 4-Glass Substrate

[0041] 5-Light Absorbing Layer

[0042] 10-Filter Detailed Embodiments

[0043] Hereinafter, embodiments of the present invention will be described.

[0044] In this specification, the near-infrared absorbing pigment is sometimes abbreviated as "NIR pigment", and the ultraviolet absorbing pigment is sometimes abbreviated as "UV pigment".

[0045] In this specification, the compound represented by formula (I) is referred to as compound (I). The same applies to compounds represented by other formulas. The pigment containing compound (I) is also referred to as pigment (I), and the same applies to other pigments. In addition, the group represented by formula (I) is also described as group (I), and the same applies to groups represented by other formulas.

[0046] In this specification, regarding the transmittance of glass, the transmittance of the light absorbing layer including the case of containing a pigment in a resin, the transmittance measured by dissolving a pigment in a solvent such as dichloromethane, the transmittance of the medium multilayer film, and the transmittance of the filter having the medium multilayer film, when it is described as "transmittance", it is all the "external (measured) transmittance" including the reflection losses on the front and back surfaces.

[0047] In this specification, the optical density represents a value obtained by conversion from the transmittance according to the following formula.

[0048] Optical density at wavelength λ nm = -log10(iT λ / 100)

[0049] iT λ : Transmittance at an incident angle of 0 degrees at wavelength λ nm

[0050] In this specification, the transmittance in a specific wavelength range being, for example, 90% or more means that the transmittance is not less than 90% in the entire wavelength range, that is, the minimum transmittance in the wavelength range is 90% or more. Similarly, the transmittance in a specific wavelength range being, for example, 1% or less means that the transmittance is not greater than 1% in the entire wavelength range, that is, the maximum transmittance in the wavelength range is 1% or less. The average transmittance in a specific wavelength range is the arithmetic mean of the transmittance per 1 nm in the wavelength range.

[0051] The spectral characteristics can be measured using an ultraviolet-visible spectrophotometer.

[0052] In this specification, "~" indicating a numerical range includes the upper and lower limits.

[0053] <Filter>

[0054] The filter according to one embodiment of the present invention (hereinafter also referred to as "this filter") is a filter having a dielectric multilayer film 1, a glass substrate, a dielectric multilayer film 2, a light absorption layer, and a dielectric multilayer film 3 in this order, and the light absorption layer contains a near-infrared absorbing dye.

[0055] Utilizing the reflection characteristics of the dielectric multilayer film and the absorption characteristics of the light absorption layer, the entire filter can achieve excellent transmittance in the visible light region and a specific near-infrared light region, as well as excellent shielding in the other near-infrared light region and the near-ultraviolet light region.

[0056] The configuration example of this filter will be described with reference to the drawings. Figure 1 It is a cross-sectional view schematically showing an example of the filter according to one embodiment.

[0057] Figure 1 The shown filter 10 is an example having a dielectric multilayer film 1, a glass substrate 4, a dielectric multilayer film 2, a light absorption layer 5, and a dielectric multilayer film 3 in this order.

[0058] This filter satisfies all of the following spectral characteristics (i-1) to (i-6).

[0059] (i-1) When one main surface is taken as the incident direction, the average reflectance of light with a wavelength of 1300 nm to 1500 nm is 90% or more at an incident angle of 5 degrees and 90% or more at an incident angle of 40 degrees;

[0060] (i-2) When one main surface is taken as the incident direction, the maximum reflectance of light with a wavelength of 1300 nm to 1500 nm is 95% or more at an incident angle of 5 degrees and 95% or more at an incident angle of 40 degrees;

[0061] (i-3) When the other main surface is taken as the incident direction, the average reflectance of light with a wavelength of 750 nm to 900 nm is 30% or more at an incident angle of 5 degrees and 30% or more at an incident angle of 40 degrees;

[0062] (i-4) When the other main surface is taken as the incident direction, the maximum reflectance of light with a wavelength of 750 nm to 900 nm is 80% or more at an incident angle of 5 degrees and 70% or more at an incident angle of 40 degrees;

[0063] (i-5) The average transmittance of light with a wavelength of 350 nm to 400 nm is 1% or less at an incident angle of 0 degrees and 2% or less at an incident angle of 40 degrees;

[0064] (i-6) The maximum transmittance of light with a wavelength of 350 nm to 400 nm is 2% or less at an incident angle of 0 degrees and 3% or less at an incident angle of 40 degrees.

[0065] The present filter that satisfies all the spectral characteristics (i-1) to (i-6) is a filter that has excellent reflection characteristics of light with wavelengths of 1300 nm to 1500 nm and 750 nm to 900 nm, which become noise, and excellent shielding properties for near-ultraviolet light even at high incident angles and is not easily affected by the incident angle.

[0066] In the spectral characteristic (i-1), the average reflectance of light with a wavelength of 1300 nm to 1500 nm is preferably 94% or more at an incident angle of 5 degrees and preferably 95% or more at an incident angle of 40 degrees.

[0067] In the spectral characteristic (i-2), the maximum reflectance of light with a wavelength of 1300 nm to 1500 nm is preferably 98% or more at an incident angle of 5 degrees and preferably 98% or more at an incident angle of 40 degrees.

[0068] In addition, it is preferable to satisfy the spectral characteristics (i-1) and (i-2) on the side of the dielectric multilayer film 1 (substrate side).

[0069] In order to satisfy the spectral characteristics (i-1) and (i-2), for example, a dielectric multilayer film having excellent reflection characteristics of light with a wavelength of 1300 nm to 1500 nm can be cited, and preferably any one of the dielectric multilayer films 1 to 3 satisfies all the following characteristics (iiA-1) to (iiA-3).

[0070] In the spectral characteristic (i-3), the average reflectance of light with a wavelength of 750 nm to 900 nm is preferably 35% or more at an incident angle of 5 degrees and preferably 35% or more at an incident angle of 40 degrees.

[0071] In the spectral characteristic (i-4), the maximum reflectance of light with a wavelength of 750 nm to 900 nm is preferably 83% or more at an incident angle of 5 degrees and preferably 76% or more at an incident angle of 40 degrees.

[0072] In addition, it is preferable to satisfy the spectral characteristics (i-3) and (i-4) on the side of the dielectric multilayer film 3 (light absorption layer side).

[0073] In order to satisfy the spectral characteristics (i-3) and (i-4), for example, a dielectric multilayer film having excellent reflection characteristics of light with a wavelength of 750 nm to 900 nm can be cited, and preferably any one of the dielectric multilayer films 1 to 3 satisfies all the following characteristics (iiC-1) to (iiC-3).

[0074] In the spectral characteristic (i-5), the average transmittance of light with a wavelength of 350 nm to 400 nm is preferably 0.1% or less at an incident angle of 0 degrees, and preferably 0.5% or less at an incident angle of 40 degrees.

[0075] In the spectral characteristic (i-6), the maximum transmittance of light with a wavelength of 350 nm to 400 nm is preferably 0.5% or less at an incident angle of 0 degrees, and preferably 2.0% or less at an incident angle of 40 degrees.

[0076] In order to satisfy the spectral characteristic (i-5) and the spectral characteristic (i-6), for example, a dielectric multilayer film having excellent reflection characteristics for light with a wavelength of 350 nm to 400 nm can be cited, and preferably any one of the dielectric multilayer films 1 to 3 satisfies all of the following characteristics (iiB-1) to (iiB-3).

[0077] This filter preferably satisfies the following spectral characteristic (i-7):

[0078] When taking any one of the main surfaces as the incident direction, the absorption loss amount x at a wavelength of X nm is defined as follows:

[0079] (Absorption loss amount X ) [%] = 100 - (transmittance at an incident angle of 0 degrees) - (reflectance at an incident angle of 5 degrees)

[0080] (i-7) The integrated value of the absorption loss amount 430-1100 in the range of 430 nm to 1100 nm is 10000 or more.

[0081] The absorption loss amount X is an index indicating the degree of light shielding based on the absorption characteristic at a wavelength of X nm. The larger the value, the more the light of the wavelength X is shielded by absorption.

[0082] The integrated value in the spectral characteristic (i-7) is more preferably 12000 or more.

[0083] In order to satisfy the spectral characteristic (i-7), for example, a near-infrared absorbing dye having a maximum absorption wavelength between 430 nm and 1100 nm can be cited.

[0084] This filter preferably satisfies all of the following spectral characteristics (i-8) to (i-11):

[0085] (i-8) When taking one of the main surfaces as the incident direction, the average reflectance of light with a wavelength of 420 nm to 650 nm is 5% or less at an incident angle of 5 degrees and 5% or less at an incident angle of 40 degrees;

[0086] (i-9) When taking one main surface as the incident direction, the maximum reflectance of light with a wavelength of 420 nm to 650 nm is 10% or less at an incident angle of 5 degrees and 15% or less at an incident angle of 40 degrees;

[0087] (i-10) When taking one main surface as the incident direction, the average reflectance of light with a wavelength of 1030 nm to 1150 nm is 9% or less at an incident angle of 5 degrees and 10% or less at an incident angle of 40 degrees;

[0088] (i-11) When taking one main surface as the incident direction, the maximum reflectance of light with a wavelength of 1030 nm to 1150 nm is 10% or less at an incident angle of 5 degrees and 15% or less at an incident angle of 40 degrees.

[0089] Satisfying all the spectral characteristics (i-8) to (i-11) indicates that the reflection characteristics of light in the visible light region and the target wavelength range are small.

[0090] In the spectral characteristic (i-8), the average reflectance of light with a wavelength of 420 nm to 650 nm is more preferably 4.5% or less at an incident angle of 5 degrees and more preferably 4.5% or less at an incident angle of 40 degrees.

[0091] In the spectral characteristic (i-9), the maximum reflectance of light with a wavelength of 420 nm to 650 nm is more preferably 7.5% or less at an incident angle of 5 degrees and more preferably 13.9% or less at an incident angle of 40 degrees.

[0092] In the spectral characteristic (i-10), the average reflectance of light with a wavelength of 1030 nm to 1150 nm is more preferably 6.0% or less at an incident angle of 5 degrees and more preferably 6.0% or less at an incident angle of 40 degrees.

[0093] In the spectral characteristic (i-11), the maximum reflectance of light with a wavelength of 1030 nm to 1150 nm is more preferably 7.0% or less at an incident angle of 5 degrees and more preferably 11.0% or less at an incident angle of 40 degrees.

[0094] In addition, it is preferable to satisfy the spectral characteristics (i-8) to (i-11) on the side of the dielectric multilayer film 1 (substrate side).

[0095] In order to satisfy the spectral characteristics (i-8) to (i-11), preferably, any one of the dielectric multilayer films 1 to 3 satisfies all the following characteristics (iiA-1) to (iiA-3).

[0096] This filter preferably satisfies all the following spectral characteristics (i-12) to (i-15):

[0097] (i-12) When taking another major surface as the incident direction, the average reflectance of light with a wavelength of 420 nm to 650 nm is 5% or less at an incident angle of 5 degrees and 5% or less at an incident angle of 40 degrees;

[0098] (i-13) When taking another major surface as the incident direction, the maximum reflectance of light with a wavelength of 420 nm to 650 nm is 10% or less at an incident angle of 5 degrees and 15% or less at an incident angle of 40 degrees;

[0099] (i-14) When taking another major surface as the incident direction, the average reflectance of light with a wavelength of 1030 nm to 1150 nm is 9% or less at an incident angle of 5 degrees and 10% or less at an incident angle of 40 degrees;

[0100] (i-15) When taking another major surface as the incident direction, the maximum reflectance of light with a wavelength of 1030 nm to 1150 nm is 10% or less at an incident angle of 5 degrees and 15% or less at an incident angle of 40 degrees.

[0101] Satisfying all the spectral characteristics (i-12) to (i-15) indicates that the reflection characteristics of light in the visible light region and the target wavelength range are small.

[0102] In the spectral characteristic (i-12), the average reflectance of light with a wavelength of 420 nm to 650 nm is more preferably 4.0% or less at an incident angle of 5 degrees and more preferably 4.0% or less at an incident angle of 40 degrees.

[0103] In the spectral characteristic (i-13), the maximum reflectance of light with a wavelength of 420 nm to 650 nm is more preferably 8.0% or less at an incident angle of 5 degrees and more preferably 14.5% or less at an incident angle of 40 degrees.

[0104] In the spectral characteristic (i-14), the average reflectance of light with a wavelength of 1030 nm to 1150 nm is more preferably 6.0% or less at an incident angle of 5 degrees and more preferably 6.0% or less at an incident angle of 40 degrees.

[0105] In the spectral characteristic (i-15), the maximum reflectance of light with a wavelength of 1030 nm to 1150 nm is more preferably 8.0% or less at an incident angle of 5 degrees and more preferably 11.0% or less at an incident angle of 40 degrees.

[0106] Additionally, it is preferable to satisfy the spectral characteristics (i-12) to (i-15) on the side of the dielectric multilayer film 3 (light absorption layer side).

[0107] In order to satisfy the spectral characteristics (i-12) to (i-15), it is preferable that any one of the dielectric multilayer films 1 to 3 satisfies all of the following characteristics (iiC-1) to (iiC-3).

[0108] <Glass substrate>

[0109] This filter has a glass substrate. Since this filter has at least three dielectric multilayer films, as a base material, a material with high rigidity like glass is preferably used instead of a resin film. Thereby, warping during film formation can be reduced.

[0110] As the glass substrate, a transparent glass substrate or a light-absorbing glass substrate can be used, but a light-absorbing glass substrate is preferred. Regarding the absorption characteristics of the light-absorbing glass substrate, unlike the reflection characteristics of the dielectric multilayer film, the light-shielding region does not shift according to the incident angle of light. Therefore, high light-shielding properties can be exhibited even at high incident angles.

[0111] As the light-absorbing glass, glass containing ytterbium is preferred. Glass containing ytterbium has the property of absorbing light in the near-infrared light region with wavelengths of 900 nm to 1000 nm. In addition, the waveform of the absorption band is steep, so the transmittance in regions other than the maximum absorption wavelength range is excellent. Therefore, the transmittance in the visible light region and the near-infrared light region from visible light to about 800 nm is excellent.

[0112] Hereinafter, each component that can constitute the glass and its appropriate content (in mol% based on oxides) will be described. In this specification, unless otherwise specified, the content and total content of each component are in mol% based on oxides.

[0113] Yb 2 O 3 is a component for effectively absorbing light near wavelengths of 900 nm to 1000 nm, particularly light with a wavelength of 940 nm, and reducing the transmittance. In the glass of this embodiment, if the content of Yb 2 O 3 is 20% or more, its effect can be sufficiently obtained. If the content of Yb 2 O 3 is 60% or less, problems such as deterioration of the devitrification resistance of the glass, deterioration of the meltability, and occurrence of stray light caused by fluorescence are less likely to occur.

[0114] Therefore, the content of Yb 2 O 3 is preferably 20% to 60%, more preferably 25% to 60%, further preferably 30% to 60%, further more preferably 35% to 60%, particularly preferably greater than 40% and less than or equal to 60%, and most preferably 45% to 60%.

[0115] SiO2 is a main component for forming glass and is a component for improving the devitrification resistance and the viscosity at the liquidus temperature of the glass. In the glass of the present embodiment, if the content of SiO 2 is 0.1% or more, problems such as the glass becoming unstable, the weather resistance decreasing, and striae occurring in the glass are less likely to occur. If the content of SiO 2 is 50% or less, problems such as the meltability of the glass becoming poor are less likely to occur.

[0116] Therefore, the content of SiO 2 is preferably 0.1% to 50%, more preferably 0.1% to 40%, still more preferably 0.1% to 30%, still more preferably 0.1% to 20%, particularly preferably 0.1% to 10%, and most preferably 0.1% to 9%.

[0117] B 2 O 3 is a main component for forming glass and is a component for improving the devitrification resistance and the viscosity at the liquidus temperature of the glass. In the glass of the present embodiment, if the content of B 2 O 3 is 15% or more, problems such as the glass becoming unstable are less likely to occur. If the content of B 2 O 3 is 40% or less, problems such as the weather resistance of the glass decreasing and striae occurring in the glass are less likely to occur.

[0118] Therefore, the content of B 2 O 3 is preferably 15% to 40%, more preferably 15% to 38%, still more preferably 15% to 36%, still more preferably 15% to 34%, particularly preferably 15% to 32%, and most preferably 15% to 30%.

[0119] As the light absorption glass, from the viewpoint of obtaining a stable glass, it preferably contains at least one of SiO 2 and B 2 O 3 . From the viewpoint of problems such as the glass becoming unstable being less likely to occur, the total content of the above components is preferably more than 65%. In addition, from the viewpoint of problems such as the meltability of the glass becoming poor being less likely to occur, the total content of the above components is preferably 80% or less.

[0120] Therefore, the total content of the above components is more preferably more than 65% and less than or equal to 79%, still more preferably more than 65% and less than or equal to 78%, still more preferably more than 65% and less than or equal to 77%, particularly preferably more than 65% and less than or equal to 76%, and most preferably more than 65% and less than or equal to 75%.

[0121] P2 O 5 is a component for improving the fusibility and stability of glass. In the glass of the present embodiment, P 2 O 5 is preferably contained in an amount of 0% to 15%. If the content of P 2 O 5 is 15% or less, problems such as deterioration of the weather resistance of the glass, phase separation of the glass, and generation of striae in the glass are less likely to occur.

[0122] P 2 O 5 is more preferably contained in an amount of 1% to 13%, further preferably 2% to 12%, further more preferably 3% to 11%, and most preferably 4% to 10%.

[0123] GeO 2 is a component for improving the devitrification resistance and the viscosity at the liquidus temperature of the glass. In the glass of the present embodiment, GeO 2 is preferably contained in an amount of 0% to 15%. If the content of GeO 2 is 15% or less, problems such as deterioration of the fusibility of the glass are less likely to occur.

[0124] GeO 2 is more preferably contained in an amount of 0% to 13%, further preferably 0% to 11%, further more preferably 0% to 9%, and most preferably 0% to 7%.

[0125] Ga 2 O 3 is a component for increasing the Young's modulus of the glass and improving the fusibility and stability. In the glass of the present embodiment, Ga 2 O 3 is preferably contained in an amount of 0% to 30%. If the content of Ga 2 O 3 is 30% or less, problems such as deterioration of the devitrification resistance of the glass, increase in reflectivity, and generation of stray light caused by reflected light are less likely to occur.

[0126] Ga 2 O 3 is more preferably contained in an amount of 0.5% to 28%, further preferably 1% to 26%, further more preferably 2% to 24%, and most preferably 3% to 22%.

[0127] ZrO 2 is a component for increasing the Young's modulus of the glass and increasing the viscosity at the liquidus temperature of the glass. In the glass of the present embodiment, ZrO 2 is preferably contained in an amount of 0% to 7%. If ZrO 2If the content is 7% or less, problems such as deterioration of the devitrification resistance and melting property of the glass are less likely to occur.

[0128] ZrO 2 The content is more preferably 0% to 6%, further preferably 0% to 5%, still further preferably 0% to 4%, and most preferably 0% to 3%.

[0129] La 2 O 3 is a component for increasing the Young's modulus of the glass and improving the melting property. In the glass of the present embodiment, La 2 O 3 The content is preferably 0.1% to 20%. If the content of La 2 O 3 is 0.1% or more, its effect can be sufficiently obtained. If the content of La 2 O 3 is 20% or less, problems such as deterioration of the devitrification resistance of the glass, increase in reflectance, and generation of stray light caused by reflected light are less likely to occur.

[0130] La 2 O 3 The content is more preferably 0.5% to 19%, further preferably 1% to 18%, still further preferably 2% to 17%, and most preferably 2% to 16%.

[0131] Al 2 O 3 is a component for increasing the Young's modulus of the glass and reducing the refractive index of the glass. In the glass of the present embodiment, Al 2 O 3 The content is preferably 0.1% to 20%. If the content of Al 2 O 3 is 0.1% or more, its effect can be sufficiently obtained. If the content of Al 2 O 3 is 20% or less, problems such as deterioration of the devitrification resistance of the glass, increase in reflectance, and generation of stray light caused by reflected light are less likely to occur.

[0132] Al 2 O 3 The content is more preferably 0.1% to 18%, further preferably 0.1% to 15%, still further preferably 0.1% to 13%, and most preferably 0.1 to 11%.

[0133] From the viewpoint of vitrifying the glass containing the Yb component without causing devitrification, Al 2 O 3 、GeO 2 、Ga 2 O3 and P 2 O 5 The total content of the components and SiO 2 and B 2 O 3 The ratio of the total content of the components, i.e., (Al 2 O 3 , GeO 2 , Ga 2 O 3 and P 2 O 5 The total content of) / (SiO 2 and B 2 O 3 The total content of) is preferably less than 0.1.

[0134] As the light-absorbing glass, within the range not impairing the object of the present invention, it may contain alkali metal oxides, alkaline earth metal oxides, Sb 2 O 3 , Cl, F, and other components.

[0135] As the glass substrate in this filter, when used for a filter, in order to prevent stray light generated by reflected light on the glass surface, it is preferable to reduce the reflectivity of the glass. The reflectivity of the glass is determined by the refractive index. Typically, the refractive index at a wavelength of 588 nm is preferably 1.700 to 1.900.

[0136] As the glass substrate, when used for a so-called dual-bandpass filter having a function of selectively allowing visible light and specific near-infrared light to transmit, it is often used with a thickness of usually 3 mm or less. From the viewpoint of reducing the weight of the component, it is preferably used with a thickness of 2 mm or less, more preferably 1 mm or less, further preferably 0.5 mm or less, and further more preferably 0.3 mm or less. In addition, from the viewpoint of ensuring the strength of the glass, the thickness is preferably 0.05 mm or more.

[0137] The glass substrate in this filter can be produced, for example, in the following manner.

[0138] First, the raw materials are weighed and mixed in such a manner as to fall within the above composition range (mixing step). The raw material mixture is placed in a platinum crucible and heated and melted at a temperature of 1200°C to 1650°C in an electric furnace (melting step). After sufficient stirring and clarification, it is poured into a mold and cut and polished to form a flat plate of a specified thickness (forming step).

[0139] In the melting process of the above manufacturing method, it is preferable to adjust the maximum temperature of the glass during melting to 1650 °C or lower. If the maximum temperature of the glass during melting is at or below the above temperature, problems such as crystallization of the glass and generation of unmelted foreign substances in the glass are less likely to occur. The above temperature is more preferably 1625 °C or lower, and further preferably 1600 °C or lower.

[0140] In addition, when the temperature in the above melting process is too low, problems such as devitrification during melting and time-consuming complete melting may occur. Therefore, it is preferably 1300 °C or higher, and more preferably 1350 °C or higher.

[0141] <Light absorption layer>

[0142] This filter has a light absorption layer containing a near-infrared absorbing dye (NIR dye). Thus, it is possible to compensate for the region not shielded by the reflection characteristics of the dielectric multilayer film through the absorption characteristics that are not affected by the incident angle.

[0143] The light absorption layer preferably satisfies all of the following spectral characteristics (iii-1) to (iii-2).

[0144] (iii-1) When the shortest wavelength at which the internal transmittance is 30% in the spectral transmittance curve in the wavelength range of 650 nm to 720 nm is set as λ A_VIS(30%) and the shortest wavelength at which the internal transmittance is 30% in the spectral transmittance curve in the wavelength range of 720 nm to 1000 nm is set as λ A_IR(30%) the following relational expression is satisfied:

[0145] |λ A_IR(30%) - λ A_VIS(30%) | ≥ 100 nm

[0146] (iii-2) When the optical density at a wavelength of 720 nm is set as OD _720 the following relational expression is satisfied:

[0147] OD _720 ≥ 2.0

[0148] In characteristic (iii-1), |λ A_IR(30%) - λ A_VIS(30%) | is an index of the near-infrared light absorption band centered at 720 nm. By |λ A_IR(30%) - λ A_VIS(30%) | being 100 nm or more, it means that it is a light absorption layer that absorbs light in this region over a wide range.

[0149] |λ A_IR(30%) - λ A_VIS(30%)|More preferably, it is 120 nm or more. Additionally, from the perspective that the longer the maximum absorption wavelength of the pigment is within a longer wavelength range, the more difficult it is to maintain a high transmittance in the visible light region, |λ A_IR(30%) -λ A_VIS(30%) |is preferably 150 nm or less.

[0150] To satisfy the characteristic (iii-1), for example, it can be cited that as the near-infrared absorbing pigment, two pigments with different maximum absorption wavelengths within the range of 680 nm to 800 nm are combined. Preferably, a pigment with a maximum absorption wavelength within the range of 680 nm to 740 nm and a pigment with a maximum absorption wavelength within the range of 740 nm to 800 nm are combined. Additionally, from the perspective of achieving wide-range absorption with a small addition amount, it can be cited that using squaraine salt pigment.

[0151] The characteristic (iii-2) means that it is a light absorption layer with high near-infrared light shielding property at 720 nm.

[0152] OD _720 is preferably 2.1 or more, and more preferably 2.2 or more.

[0153] To satisfy the characteristic (iii-2), for example, it can be cited that as the near-infrared absorbing pigment, from the perspective of strongly absorbing light near 720 nm and maintaining a high transmittance in the visible light region, using symmetric squaraine salt pigment.

[0154] The near-infrared absorbing pigment (NIR pigment) is preferably a pigment having a maximum absorption wavelength within the wavelength range of 680 nm to 800 nm in dichloromethane (hereinafter, also referred to as "NIR pigment"). By including this pigment, as shown in the above characteristics (iii-1) and (iii-2), the light absorption layer can widely absorb light in the near-infrared light absorption band centered at 720 nm, and it is easy to achieve both visible light transmittance at 450 nm and near-infrared light shielding property at 720 nm.

[0155] As the near-infrared absorbing pigment, from the perspective of being able to widely absorb light in the near-infrared light region while maintaining the transmittance in the visible light region, two or more, more preferably three pigments with different maximum absorption wavelengths within the range of 680 nm to 800 nm can be combined. In particular, as the near-infrared absorbing pigment, it is preferably included a pigment having a maximum absorption wavelength within the range of greater than or equal to 700 nm and less than 730 nm, a pigment having a maximum absorption wavelength within the range of greater than or equal to 730 nm and less than 760 nm, and a pigment having a maximum absorption wavelength within the range of greater than or equal to 760 nm and less than 800 nm.

[0156] As the NIR pigment, it is preferably selected from the group consisting of squaraine pigments, cyanine pigments, phthalocyanine pigments, naphthalocyanine pigments, dithiol metal complex pigments, azo pigments, polymethine pigments, phthalide pigments, naphthoquinone pigments, anthraquinone pigments, indophenol pigments, pyran pigments, thiopyran pigments, croconic acid pigments, tetradehydrocholine pigments, triphenylmethane pigments, ammonium pigments and diammonium pigments. As the NIR pigment, it is particularly preferably at least one pigment selected from squaraine pigments, phthalocyanine pigments and cyanine pigments. Among these NIR pigments, from the viewpoint of spectroscopy, it is further preferably any one or two of squaraine pigments and cyanine pigments, and from the viewpoint of durability, it is preferably phthalocyanine pigments. pigments, thiopyran pigments, croconic acid pigments, tetradehydrocholine pigments, triphenylmethane pigments, ammonium pigments and diammonium pigments.

[0157] As the NIR pigment, it is particularly preferably at least one pigment selected from squaraine pigments, phthalocyanine pigments and cyanine pigments. Among these NIR pigments, from the viewpoint of spectroscopy, it is further preferably any one or two of squaraine pigments and cyanine pigments, and from the viewpoint of durability, it is preferably phthalocyanine pigments. pigments, phthalocyanine pigments and cyanine pigments. Among these NIR pigments, from the viewpoint of spectroscopy, it is further preferably any one or two of squaraine pigments and cyanine pigments, and from the viewpoint of durability, it is preferably phthalocyanine pigments. pigments, cyanine pigments, and from the viewpoint of durability, it is preferably phthalocyanine pigments.

[0158] The content of the NIR pigment in the light absorption layer is preferably 10% by mass or more, more preferably 20% by mass or less, and still more preferably 15% by mass or less. It should be noted that in the case of combining two or more compounds, the above content is the sum of each compound.

[0159] The light absorption layer preferably contains a near-infrared absorbing pigment and a resin. As the resin, there is no limitation as long as it is a transparent resin, and one or more transparent resins selected from polyester resins, acrylic resins, epoxy resins, ene-thiol resins, polycarbonate resins, polyether resins, polyarylate resins, polysulfone resins, polyethersulfone resins, polyphenylene resins, polyarylene ether phosphine oxide resins, polyamide resins, polyimide resins, polyamideimide resins, polyolefin resins, cyclic olefin resins, polyurethane resins and polystyrene resins can be used. These resins can be used alone or in combination of two or more.

[0160] From the viewpoints of the spectral characteristics, glass transition temperature (Tg), and adhesion of the light absorption layer, one or more resins selected from polyimide resins, polycarbonate resins, polyester resins, and acrylic resins are preferred.

[0161] When using multiple compounds as NIR pigments and other pigments, they can be contained in the same light absorption layer, or they can be contained in different light absorption layers respectively.

[0162] The light absorption layer can be formed by preparing a coating solution by dissolving or dispersing a pigment, a resin or a raw material component of the resin, and each component blended as needed in a solvent, coating the solution on a support and drying it, and further curing it as needed. The support can be a light absorption glass substrate or a peelable support used only when forming the light absorption layer. In addition, the solvent can be a dispersion medium capable of stably dispersing or a solvent capable of dissolving.

[0163] In addition, in order to improve voids caused by minute bubbles, depressions caused by adhesion of foreign substances, etc., and shrinkage holes in the drying process, the coating solution can contain a surfactant. In addition, in the coating of the coating solution, for example, dip coating, casting coating, or spin coating can be used. In addition, when the coating solution contains a raw material component of a transparent resin, a curing treatment such as heat curing or light curing is further performed.

[0164] In addition, the light absorption layer can be formed into a film shape by extrusion molding. The obtained film-shaped absorption layer is laminated on a light absorption glass substrate and integrated by thermocompression bonding or the like, whereby this optical filter can be manufactured.

[0165] The optical filter can have one light absorption layer or two or more light absorption layers. In the case of having two or more light absorption layers, each layer can have the same constitution or different constitutions.

[0166] From the viewpoints of the in-plane film thickness distribution in the coated substrate and the appearance quality, the thickness of the light absorption layer is preferably 5 μm or less. In addition, from the viewpoint of reducing the thermal expansion amount of the resin, the thickness of the light absorption layer is more preferably 2 μm or less. In addition, from the viewpoint of exhibiting the desired spectral characteristics at an appropriate pigment concentration, the thickness of the light absorption layer is preferably 0.5 μm or more. It should be noted that in the case where the optical filter has two or more light absorption layers, it is preferable that the total thickness of each light absorption layer is within the above range.

[0167] <Dielectric multilayer film>

[0168] This optical filter has three dielectric multilayer films on one main surface side of the glass substrate, the other main surface side of the glass substrate, and the surface of the light absorption layer. When the thickness of the dielectric multilayer film is large, it is easy to control the spectral characteristics. On the other hand, when the thickness of the dielectric multilayer film is too thick, stress is likely to be generated, which becomes one of the causes of deformation. By having dielectric multilayer films at three positions, the action can be dispersed in the control of the spectral characteristics, or the thickness can be prevented from concentrating on one multilayer film.

[0169] The dielectric multilayer films 1 to 3 are preferably designed as reflection films that reflect a part of near-infrared light and reflection films that reflect near-ultraviolet light.

[0170] At least one of the dielectric multilayer films 1 to 3 preferably satisfies all of the following characteristics (iiA-1) to (iiA-3).

[0171] (iiA-1) The total number of stacked layers is 1 to 80.

[0172] (iiA-2) It includes a high refractive index layer HA having a refractive index of 1.8 or more and 2.5 or less and a low refractive index layer LA having a refractive index of 1.4 or more and 1.6 or less, and the ratio of the total physical film thickness of the high refractive index layer HA to the total physical film thickness of the low refractive index layer LA is 0.3 to 0.8.

[0173] (iiA-3) When the QWOT in the high refractive index layer is 1.0 or more and the nth layer close to the glass substrate is set as the HA n layer, and the layer in the low refractive index layer where the QWOT is 1.0 or more and the layer immediately after the HA n layer close to the glass substrate is set as the LA n layer,

[0174] the layer between the HA n layer and the LA n layer is the MA 2n-1 layer, and the MA 2n-1 layer includes a single layer or multiple layers and the total QWOT is 1 or less,

[0175] the layer between the LA n layer and the HA n+1 layer where the QWOT is 1.0 or more and the (n + 1)th layer close to the glass substrate is the MA 2n layer, and the MA 2n layer includes a single layer or multiple layers and the total QWOT is 1 or less,

[0176] It has a repeating structure shown by the following formula (n is a natural number of 2 or more):

[0177] (HA 1 layer / MA 1 layer / LA 1 layer / MA 2 layer)……(HA n layer / MA 2n-1 layer / LA n layer / MA 2n layer).

[0178] By satisfying the characteristics (iiA-1) to (iiA-3), it is possible to obtain a dielectric multilayer film having excellent visible light transmittance and transmittance in the short wavelength range of near-infrared light, preferably near-infrared light of 1000 nm or less, and excellent sharp cut-off property in the long wavelength range of near-infrared light, preferably near-infrared light of 1100 nm or more.

[0179] The total number of stacked layers in (iiA-1) is more preferably 1 to 70.

[0180] The ratio of the total physical film thickness in (iiA-2) is more preferably 0.4 to 0.6.

[0181] In (iiA-3), n is more preferably 2 to 8. In addition, the repeating structures may be continuous with each other or separated, but from the viewpoint of obtaining the desired spectral characteristics, continuity is preferred.

[0182] It should be noted that the refractive index refers to the refractive index at a wavelength of 500 nm. The same applies to the characteristics hereafter.

[0183] In addition, QWOT refers to the optical film thickness of 1 / 4 wavelength.

[0184] At least one of the dielectric multilayer films 1 to 3 preferably satisfies all of the following characteristics (iiB-1) to (iiB-3).

[0185] (iiB-1) The total number of stacked layers is 1 to 60.

[0186] (iiB-2) It includes a high refractive index layer HB with a refractive index of 1.8 or more and 2.5 or less and a low refractive index layer LB with a refractive index of 1.4 or more and 1.6 or less, and the ratio of the total physical film thickness of the high refractive index layer HB to the total physical film thickness of the low refractive index layer LB is 0.2 to 0.8.

[0187] (iiB-3) When the high refractive index layer with QWOT of 1.0 or more is defined as the HB 1 layer, and the low refractive index layer with QWOT of 1.0 or more is defined as the LB 1 layer,

[0188] the layer between the HB 1 layer and the LB 1 layer is the MB 1 layer, the MB 1 layer includes a single layer or multiple layers, and the QWOT of each layer of all these layers is 1.0 or less,

[0189] It has one or more stacked structures represented by the following formula:

[0190] (HB 1 layer / MB 1 layer / LB 1 layer).

[0191] By satisfying the characteristics (iiB-1) to (iiB-3), a dielectric multilayer film with excellent visible light transmittance, excellent near-infrared light transmittance, and excellent sharp cut-off property for near-ultraviolet light can be obtained.

[0192] The total number of stacked layers in (iiB-1) is more preferably 1 to 20.

[0193] The ratio of the total physical film thickness in (iiB-2) is more preferably 0.25 to 0.75.

[0194] The number of stacked structures in (iiB-3) is more preferably 1. Additionally, in the case of having two or more stacked structures, the stacked structures may be continuous or separated from each other, but from the viewpoint of obtaining the desired spectral characteristics, continuity is preferred.

[0195] At least one of the dielectric multilayer films 1 to 3 preferably satisfies all of the following characteristics (iiC-1) to (iiC-3).

[0196] (iiC-1) The total number of stacked layers is 1 to 60.

[0197] (iiC-2) It includes a high refractive index layer HC with a refractive index of 1.8 or more and 2.5 or less and a low refractive index layer LC with a refractive index of 1.4 or more and 1.6 or less. The ratio of the total physical film thickness of the high refractive index layer HC to the total physical film thickness of the low refractive index layer LC is 0.5 to 0.9, and the ratio of the total QWOT of the high refractive index layer HC to the total QWOT of the low refractive index layer LC is 1.1 to 1.5.

[0198] (iiC-3) It has a stacked structure represented by the following formula:

[0199] (HC 2 layer / LC 2 layer / HC 2 layer) / MC 1 layer / (LC 1 layer / HC 1 layer / LC 1 layer) / MC 1 layer / (HC 2 layer / LC 2 layer / HC 2 layer)

[0200] HC 1 layer, HC 2 layer are each independently a high refractive index layer with a QWOT of 1.0 or more;

[0201] LC 1 layer, LC 2 layer are each independently a low refractive index layer with a QWOT of 1.0 or more;

[0202] MC 1 layer are each independently a layer with a total QWOT of 1 or less and including a single layer or multiple layers.

[0203] By satisfying the characteristics (iiC-1) to (iiC-3), a dielectric multilayer film excellent in visible light transmittance and transmittance of near-infrared light in a long wavelength range, preferably 1100 nm or more, and excellent in sharp cut-off property of near-infrared light in a short wavelength range, preferably 1000 nm or less, can be obtained.

[0204] The total number of stacked layers in (iiC-1) is more preferably 1 to 45.

[0205] The ratio of the total physical film thickness in (iiC-2) is more preferably 0.6 to 0.8.

[0206] The ratio of the total QWOT in (iiC-2) is more preferably 1.1 to 1.35.

[0207] As the stacked structure in (iiC-3), the following stacked structure is more preferable:

[0208] (HC 3 layer / MC 3 layer / HC 3 layer) / (MC 2 layer / LC 3 layer / MC 2 layer) / (HC 2 layer / LC 2 layer / HC 2 layer) / MC 1 layer / (LC 1 layer / HC 1 layer / LC 1 layer) / MC 1 layer / (HC 2 layer / LC 2 layer / HC 2 layer) / (MC 2 layer / LC 3 layer / MC 2 layer) / (HC 3 layer / MC 3 layer / HC 3 layer)

[0209] HC 1 layer, HC 2 layer, LC 1 layer, LC 2 layer, MC 1 layer: same as the above definition;

[0210] HC 3 Each layer is independently a high refractive index layer with a QWOT of 0.8 or more;

[0211] LC 3Each layer is independently a low refractive index layer with a QWOT of 1.0 or more;

[0212] MC 2 Each layer is independently a layer with a total QWOT of 1 or less and including one or more layers;

[0213] MC 3 Each layer is independently a layer with a total QWOT of 2 or less and including one or more layers.

[0214] More preferably, any one of the dielectric multilayer films 1 to 3 respectively satisfies the above characteristics (iiA-1) to (iiA-3), characteristics (iiB-1) to (iiB-3), and characteristics (iiC-1) to (iiC-3). Thus, by using the reflection characteristics of the three dielectric multilayer films, it is possible to impart sharp cut-off properties for near-ultraviolet light, high visible light transmittance, and sharp cut-off properties on the short-wavelength side and long-wavelength side of the target wavelength to the filter. Particularly preferably, the dielectric multilayer film 1 satisfies the characteristics (iiA-1) to (iiA-3), the dielectric multilayer film 2 satisfies the characteristics (iiB-1) to (iiB-3), and the dielectric multilayer film 3 satisfies the characteristics (iiC-1) to (iiC-3).

[0215] The dielectric multilayer film is a laminate of dielectric films with different refractive indices. More specifically, examples include: a low refractive index dielectric film (low refractive index film), a medium refractive index dielectric film (medium refractive index film), a high refractive index dielectric film (high refractive index film), and a dielectric multilayer film composed of laminating two or more of them. When allowing transmission of a desired wavelength band and selecting a desired wavelength band, by combining dielectric films with different spectral characteristics, the reflection characteristics can be adjusted.

[0216] The refractive index of the high refractive index material at a wavelength of 500 nm is preferably 1.8 or more and 2.5 or less, more preferably 1.9 or more and 2.5 or less. Examples of the high refractive index material include: Ta 2 O 5 、TiO 2 、TiO、Nb 2 O 5 . Examples of other commercially available products include: OS50 (Ti 3 O 5 ) manufactured by Canon Optron Co., Ltd., OS10 (Ti 4 O 7 ), OA500 (a mixture of Ta 2 O 5 and ZrO 2 ), OA600 (Ta 2 O 5 and TiO 2mixtures), etc. Among them, from the aspects of reproducibility and stability of film-forming property, refractive index, etc., TiO is preferred. 2 .

[0217] The refractive index of the medium refractive index material at a wavelength of 500 nm is preferably greater than 1.5 and less than 1.8, more preferably greater than or equal to 1.55 and less than 1.8. As the medium refractive index material, examples include: ZrO 2 , Nb 2 O 5 , Al 2 O 3 , HfO 2 , OM-4 and OM-6 sold by Canon Optron Co., Ltd. (a mixture of Al 2 O 3 and ZrO 2 ), OA-100, H4 and M2 (aluminum oxide-lanthanum oxide) sold by Merck & Co., Inc., etc. Among them, from the aspects of reproducibility, stability, etc. of film-forming property, refractive index, etc., Al 2 O 3 compounds and the mixture of Al 2 O 3 and ZrO 2 are preferred. It should be noted that the medium refractive index film may also be replaced with an equivalent film containing a high refractive index film and a low refractive index film without using the above-mentioned medium refractive index material.

[0218] The refractive index of the low refractive index material at a wavelength of 500 nm is preferably 1.4 or more and 1.6 or less, more preferably 1.45 or more and 1.5 or less. As the low refractive index material, for example, SiO 2 , SiO x N y , MgF 2 , etc. As other commercially available products, examples include: S4F and S5F manufactured by Canon Optron Co., Ltd. (a mixture of SiO 2 and Al 2 O 3 ). Among them, from the aspects of reproducibility, stability, economy, etc. of film-forming property, SiO 2 is preferred.

[0219] From the viewpoint of easily controlling spectral characteristics, the film thickness (physical film thickness) of the dielectric multilayer film 1 is preferably 1 μm or more, more preferably 2 μm or more. In addition, from the viewpoints of productivity and suppressing reflection ripples in the visible light region, it is preferably 6 μm or less.

[0220] From the viewpoint of easily controlling spectral characteristics, the film thickness (physical film thickness) of the dielectric multilayer film 2 is preferably 0.2 μm or more, more preferably 0.5 μm or more. Further, from the viewpoints of productivity and suppressing reflection ripples in the visible light region, it is preferably 6 μm or less.

[0221] From the viewpoint of easily controlling spectral characteristics, the film thickness (physical film thickness) of the dielectric multilayer film 3 is preferably 1 μm or more, more preferably 2 μm or more. Further, from the viewpoints of productivity and suppressing reflection ripples in the visible light region, it is preferably 6 μm or less.

[0222] In the formation of the dielectric multilayer film, for example, vacuum film-forming processes such as CVD method, sputtering method, vacuum evaporation method, etc.; wet film-forming processes such as spray method, dipping method, etc. can be used.

[0223] This filter can have, for example, constituent elements (layers) that generate absorption using inorganic fine particles that control the transmission and absorption of light in a specific wavelength range as other constituent elements. Specific examples of the inorganic fine particles include: ITO (Indium Tin Oxides), ATO (Antimony-doped Tin Oxides), cesium tungstate, lanthanum boride, etc. Since ITO fine particles and cesium tungstate fine particles have high visible light transmittance and light absorption properties in a wide range of infrared wavelength ranges greater than 1200 nm, they can be used when shielding of this infrared light is required.

[0224] <Imaging device>

[0225] The imaging device according to an embodiment of the present invention preferably has the filter according to the embodiment of the present invention described above. The imaging device preferably further has a solid-state imaging element and an imaging lens. The filter of the present embodiment can be used, for example, by being disposed between the imaging lens and the solid-state imaging element or directly adhered to the solid-state imaging element, imaging lens, etc. of the imaging device through an adhesive layer. By having this filter with excellent transmittance of visible light and specific near-infrared light, having shielding properties for specific near-infrared light, and having a spectral curve that is not easily shifted even at a high incident angle, an imaging device with excellent color reproducibility even for light at a high incident angle can be obtained.

[0226] When the filter is mounted in the imaging device, it is generally preferred that the dielectric multilayer film 1 is on the lens side and the dielectric multilayer film 3 is on the sensor side, but it is not limited thereto.

[0227] As described above, the following filters and the like are disclosed in this specification.

[0228] [1] A filter, which successively has a dielectric multilayer film (1), a glass substrate, a dielectric multilayer film (2), a light absorption layer, and a dielectric multilayer film (3), wherein,

[0229] the light absorption layer contains a near-infrared absorption pigment,

[0230] the filter satisfies all of the following spectral characteristics (i-1) to (i-6):

[0231] (i-1) When one main surface is taken as the incident direction, the average reflectance of light with a wavelength of 1300 nm to 1500 nm is 90% or more at an incident angle of 5 degrees and 90% or more at an incident angle of 40 degrees;

[0232] (i-2) When one main surface is taken as the incident direction, the maximum reflectance of light with a wavelength of 1300 nm to 1500 nm is 95% or more at an incident angle of 5 degrees and 95% or more at an incident angle of 40 degrees;

[0233] (i-3) When the other main surface is taken as the incident direction, the average reflectance of light with a wavelength of 750 nm to 900 nm is 30% or more at an incident angle of 5 degrees and 30% or more at an incident angle of 40 degrees;

[0234] (i-4) When the other main surface is taken as the incident direction, the maximum reflectance of light with a wavelength of 750 nm to 900 nm is 80% or more at an incident angle of 5 degrees and 70% or more at an incident angle of 40 degrees;

[0235] (i-5) The average transmittance of light with a wavelength of 350 nm to 400 nm is 1% or less at an incident angle of 0 degrees and 2% or less at an incident angle of 40 degrees;

[0236] (i-6) The maximum transmittance of light with a wavelength of 350 nm to 400 nm is 2% or less at an incident angle of 0 degrees and 3% or less at an incident angle of 40 degrees.

[0237] [2] The filter according to [1], wherein at least one of the dielectric multilayer films (1) to (3) satisfies all of the following characteristics (iiB-1) to (iiB-3):

[0238] (iiB-1) The total number of stacked layers is 1 to 60;

[0239] (iiB-2) It contains a high refractive index layer HB with a refractive index of 1.8 or more and 2.5 or less and a low refractive index layer LB with a refractive index of 1.4 or more and 1.6 or less, and the ratio of the total physical film thickness of the high refractive index layer HB to the total physical film thickness of the low refractive index layer LB is 0.2 to 0.8;

[0240] (iiB-3) When the high refractive index layer with QWOT of 1.0 or more is set as the HB 1 layer, and the low refractive index layer with QWOT of 1.0 or more is set as the LB 1 layer,

[0241] the HB 1 layer and the LB 1 layer, the layer therebetween is the MB 1 layer, the MB 1 layer includes a single layer or multiple layers, and the QWOT of each layer of all these layers is 1.0 or less,

[0242] having a stacked structure represented by the following formula with 1 or more:

[0243] (HB 1 layer / MB 1 layer / LB 1 layer).

[0244] [3] The filter according to [1] or [2], wherein at least one of the dielectric multilayer films (1) to (3) satisfies all of the following characteristics (iiA-1) to (iiA-3):

[0245] (iiA-1) The total number of stacked layers is 1 to 80;

[0246] (iiA-2) It includes a high refractive index layer HA with a refractive index of 1.8 or more and 2.5 or less and a low refractive index layer LA with a refractive index of 1.4 or more and 1.6 or less, and the ratio of the total physical film thickness of the high refractive index layer HA to the total physical film thickness of the low refractive index layer LA is 0.3 to 0.8;

[0247] (iiA-3) When the layer in the high refractive index layer with QWOT of 1.0 or more and the nth layer close to the glass substrate is set as the HA n layer, and the layer in the low refractive index layer with QWOT of 1.0 or more and the layer immediately following the layer HA n and close to the glass substrate is set as the LA n layer,

[0248] the HA n layer and the LA n layer, the layer therebetween is the MA 2n-1 layer, the MA 2n-1 layer includes a single layer or multiple layers and the total QWOT is 1 or less,

[0249] the LA n layer and the layer between the LA layer and the HA layer with QWOT of 1.0 or more and the (n + 1)th layer close to the glass substrate is the MA n+1 layer 2nlayer, the MA 2n layer includes a single layer or multiple layers and the total QWOT is 1 or less,

[0250] having a repeating structure represented by the following formula (n is a natural number of 2 or more):

[0251] (HA 1 layer / MA 1 layer / LA 1 layer / MA 2 layer)……(HA n layer / MA 2n-1 layer / LA n layer / MA 2n layer).

[0252] [4] The optical filter according to any one of [1] to [3], wherein at least one of the dielectric multilayer films (1) to (3) satisfies all of the following characteristics (iiC-1) to (iiC-3):

[0253] (iiC-1) The total number of stacked layers is 1 to 60;

[0254] (iiC-2) It includes a high refractive index layer HC with a refractive index of 1.8 or more and 2.5 or less and a low refractive index layer LC with a refractive index of 1.4 or more and 1.6 or less. The ratio of the total physical film thickness of the high refractive index layer HC to the total physical film thickness of the low refractive index layer LC is 0.5 to 0.9, and the ratio of the total QWOT of the high refractive index layer HC to the total QWOT of the low refractive index layer LC is 1.1 to 1.5;

[0255] (iiC-3) It has a stacked structure represented by the following formula:

[0256] (HC 2 layer / LC 2 layer / HC 2 layer) / MC 1 layer / (LC 1 layer / HC 1 layer / LC 1 layer) / MC 1 layer / (HC 2 layer / LC 2 layer / HC 2 layer)

[0257] HC 1 layer, HC 2 layer are each independently a high refractive index layer with a QWOT of 1.0 or more;

[0258] LC 1 layer, LC 2 layer are each independently a low refractive index layer with a QWOT of 1.0 or more;

[0259] MC 1 Each layer is independently a layer having a total QWOT of 1 or less and including one or more layers.

[0260] [5] The filter according to any one of [1] to [4], wherein the glass substrate contains ytterbium.

[0261] [6] The filter according to any one of [1] to [5], wherein

[0262] the filter satisfies the following spectral characteristic (i-7):

[0263] When any one of the main surfaces is taken as the incident direction, the absorption loss amount x at a wavelength of X nm is defined as follows:

[0264] (Absorption loss amount X ) [%] = 100 - (transmittance at an incident angle of 0 degrees) - (reflectance at an incident angle of 5 degrees)

[0265] (i-7) The integrated value of the absorption loss amount in the wavelength range of 430 nm to 1100 nm 430-1100 is 10,000 or more.

[0266] [7] The filter according to any one of [1] to [6], wherein

[0267] in terms of mol% based on oxides, the glass substrate contains:

[0268] 0.1 mol% to 50 mol% of SiO 2 ,

[0269] 15 mol% to 40 mol% of B 2 O 3 ,

[0270] 0 mol% to 15 mol% of P 2 O 5 , and

[0271] 20 mol% to 60 mol% of Yb 2 O 3 .

[0272] [8] The filter according to any one of [1] to [7], wherein

[0273] the near-infrared absorbing pigment contains a pigment having a maximum absorption wavelength in the wavelength range of 680 nm to 800 nm,

[0274] the light absorption layer satisfies all of the following spectral characteristics (iii-1) to (iii-2):

[0275] (iii-1) When the shortest wavelength at which the internal transmittance is 30% in the spectral transmittance curve in the wavelength range of 650 nm to 720 nm is set as λ A_VIS(30%) and the shortest wavelength at which the internal transmittance is 30% in the spectral transmittance curve in the wavelength range of 720 nm to 1000 nm is set as λ A_IR(30%) the following relational expression is satisfied:

[0276] |λ A_IR(30%) -λ A_VIS(30%) |≥100 nm

[0277] (iii-2) When the optical density at a wavelength of 720 nm is set as OD _720 the following relational expression is satisfied:

[0278] OD _720 ≥2.0.

[0279] [9] The filter according to any one of [1] to [8], wherein the filter satisfies all of the following spectral characteristics (i-8) to (i-11):

[0280] (i-8) When one main surface is used as the incident direction, the average reflectance of light with a wavelength of 420 nm to 650 nm is 5% or less at an incident angle of 5 degrees and 5% or less at an incident angle of 40 degrees;

[0281] (i-9) When one main surface is used as the incident direction, the maximum reflectance of light with a wavelength of 420 nm to 650 nm is 10% or less at an incident angle of 5 degrees and 15% or less at an incident angle of 40 degrees;

[0282] (i-10) When one main surface is used as the incident direction, the average reflectance of light with a wavelength of 1030 nm to 1150 nm is 9% or less at an incident angle of 5 degrees and 10% or less at an incident angle of 40 degrees;

[0283] (i-11) When one main surface is used as the incident direction, the maximum reflectance of light with a wavelength of 1030 nm to 1150 nm is 10% or less at an incident angle of 5 degrees and 15% or less at an incident angle of 40 degrees.

[0284]

[10] The filter according to any one of [1] to [9], wherein the filter satisfies all of the following spectral characteristics (i-12) to (i-15):

[0285] (i-12) When the other main surface is used as the incident direction, the average reflectance of light with a wavelength of 420 nm to 650 nm is 5% or less at an incident angle of 5 degrees and 5% or less at an incident angle of 40 degrees;

[0286] (i-13) When another major surface is used as the incident direction, the maximum reflectance of light with wavelengths from 420 nm to 650 nm is 10% or less at an incident angle of 5 degrees and 15% or less at an incident angle of 40 degrees;

[0287] (i-14) When another major surface is used as the incident direction, the average reflectance of light with wavelengths from 1030 nm to 1150 nm is 9% or less at an incident angle of 5 degrees and 10% or less at an incident angle of 40 degrees;

[0288] (i-15) When another major surface is used as the incident direction, the maximum reflectance of light with wavelengths from 1030 nm to 1150 nm is 10% or less at an incident angle of 5 degrees and 15% or less at an incident angle of 40 degrees.

[0289]

[11] An imaging device, wherein the imaging device has the optical filter according to any one of [1] to

[10] .

[0290] Examples

[0291] Next, the present invention will be described more specifically by way of examples.

[0292] In the measurement of each spectral characteristic, a UV-visible spectrophotometer (manufactured by Hitachi High-Technologies Corporation, model UH-4150) was used.

[0293] It should be noted that the spectral characteristics in the case where the incident angle is not specifically specified are the values measured under the condition of an incident angle of 0 degrees (the direction perpendicular to the major surface of the optical filter).

[0294] The pigments used in each example are as follows.

[0295] Compound 1 (cyanine compound): Synthesized based on Dyes and pigments 73 (2007) 344-352.

[0296] Compound 2 (mero-cyanine compound): Synthesized based on the specification of German Patent Gazette No. 10109243.

[0297] Compound 3 (squaraine salt compound): Synthesized based on the specification of US Patent No. 5543086.

[0298] It should be noted that Compound 1 and Compound 3 are near-infrared absorbing pigments (NIR pigments), and Compound 2 is a near-ultraviolet absorbing pigment (UV pigment).

[0299]

[0300] <Spectral characteristics of pigments>

[0301] The maximum absorption wavelengths in the absorption spectra measured by dissolving the above pigments (Compounds 1 to 3) in dichloromethane are shown in Table 1 described later.

[0302] <Glass Substrate>

[0303] As the glass substrate, Glass A, which is a light-absorbing glass, and non-absorbing Glass B were prepared.

[0304] Regarding Glass A, in terms of mol% in terms of oxide conversion, to make SiO 2 7.5%, B 2 O 3 23.6%, P 2 O 5 7.5%, Yb 2 O 3 47.2%, Ga 2 O 3 11.8%, La 2 O 3 2.4%, the raw materials were weighed and mixed, placed in a crucible with an internal volume of about 400 cc, melted at 1400 °C to 1650 °C for 2 hours in an air atmosphere. Then, clarification and stirring were carried out, and it was poured into a rectangular mold with a length of 100 mm × width of 50 mm × height of 20 mm preheated to about 300 °C to 500 °C, and slowly cooled to room temperature at about -1 °C / minute, and cut to a specified thickness within the range of length 40 mm × width 30 mm × thickness 0.3 mm to 1.5 mm, and both sides were optically polished to obtain a plate-shaped glass.

[0305] In addition, Glass B is a non-absorbing glass, and D263 glass (manufactured by Schott, borosilicate glass, commercially available product) was used.

[0306] It should be noted that the raw materials of each glass are the raw materials shown below.

[0307] SiO 2 : Oxide

[0308] B 2 O 3 : Selected from oxide, PBO 4 and H 3 BO 3 One or more of them

[0309] P 2 O 5 : H 3 PO 4 and PBO 4 Any one or more of them

[0310] GeO2 : Oxide

[0311] ZrO 2 : Oxide

[0312] Ga 2 O 3 : Oxide

[0313] Yb 2 O 3 : Oxide

[0314] La 2 O 3 : Oxide

[0315] Al 2 O 3 : Oxide and Al(OH) 3 any one or more of

[0316] It should be noted that the raw materials of the glass are not limited to the above substances, and known raw materials can be used.

[0317] The transmittance curves of light with wavelengths from 350 nm to 1200 nm of Glass A and Glass B (both Glass A and Glass B have a plate thickness of 0.4 mm and internal transmittance) are shown in Figure 2 .

[0318] <Light absorption layer>

[0319] Any one of Compounds 1 to 3 was dissolved in a polyimide resin (manufactured by Mitsubishi Gas Chemical Company, Inc., C-3G30G), mixed at the concentrations recorded in the following table, and stirred and dissolved at 50 °C for 2 hours to obtain a coating solution.

[0320] The obtained coating solution was coated on an alkali glass (manufactured by Schott AG, D263 glass, thickness 0.2 mm) by spin coating to form a light absorption layer with the film thickness and spectral characteristics shown in Table 1 below.

[0321] In addition, the transmittance curve of light with wavelengths from 350 nm to 1200 nm of the light absorption layer is shown in Figure 3 .

[0322] [Table 1]

[0323]

[0324] <Example 1: Filter>

[0325] SiO was alternately laminated on one main surface of a glass substrate (Glass A) by evaporation 2 and TiO 2 to form a dielectric multilayer film A1.

[0326] SiO and TiO were alternately laminated on the other main surface of the glass substrate by evaporation coating, and thus the dielectric multilayer film B1 was formed. 2 and TiO 2 Thereby, the dielectric multilayer film B1 was formed.

[0327] The resin solution was coated on the surface of the dielectric multilayer film B1 with the same composition as the light absorption layer 1, and heated sufficiently to remove the organic solvent, thereby forming the light absorption layer.

[0328] SiO and TiO were alternately laminated on the surface of the light absorption layer by evaporation coating, and thus the dielectric multilayer film C1 was formed. 2 and TiO 2 Thereby, the dielectric multilayer film C1 was formed.

[0329] The filter of Example 1 was manufactured in the above manner.

[0330] <Example 2>

[0331] SiO and TiO were alternately laminated on one main surface of the glass substrate (Glass A) by evaporation coating, and thus the dielectric multilayer film A2 was formed. 2 and TiO 2 Thereby, the dielectric multilayer film A2 was formed.

[0332] SiO and TiO were alternately laminated on the other main surface of the glass substrate by evaporation coating, and thus the dielectric multilayer film C2 was formed. 2 and TiO 2 Thereby, the dielectric multilayer film C2 was formed.

[0333] The resin solution was coated on the surface of the dielectric multilayer film C2 with the same composition as the light absorption layer 1, and heated sufficiently to remove the organic solvent, thereby forming the light absorption layer.

[0334] SiO and TiO were alternately laminated on the surface of the light absorption layer by evaporation coating, and thus the dielectric multilayer film B2 was formed. 2 and TiO 2 Thereby, the dielectric multilayer film B2 was formed.

[0335] The filter of Example 2 was manufactured in the above manner.

[0336] <Example 3>

[0337] SiO and TiO were alternately laminated on one main surface of the glass substrate (Glass A) by evaporation coating, and thus the dielectric multilayer film C3 was formed. 2 and TiO 2 Thereby, the dielectric multilayer film C3 was formed.

[0338] SiO and TiO were alternately laminated on the other main surface of the glass substrate by evaporation coating, and thus the dielectric multilayer film A3 was formed. 2 and TiO 2 Thereby, the dielectric multilayer film A3 was formed.

[0339] A resin solution was coated on the surface of the dielectric multilayer film A3 with the same composition as the light absorption layer 1, and heated sufficiently to remove the organic solvent, thereby forming the light absorption layer.

[0340] SiO was alternately laminated on the surface of the light absorption layer by vapor deposition 2 and TiO 2 , thereby forming the dielectric multilayer film B3.

[0341] The filter of Example 3 was manufactured in the above manner.

[0342] <Example 4>

[0343] Except for using glass B instead of glass A as the glass substrate, the same operations as in Example 1 were performed, thereby manufacturing the filter of Example 4.

[0344] <Example 5: Filter>

[0345] SiO was alternately laminated on one main surface of the glass substrate (glass A) by vapor deposition 2 and TiO 2 , thereby forming the dielectric multilayer film X1.

[0346] SiO was alternately laminated on the other main surface of the glass substrate by vapor deposition 2 and TiO 2 , thereby forming the dielectric multilayer film X2.

[0347] A resin solution was coated on the surface of the dielectric multilayer film X2 with the same composition as the light absorption layer 1, and heated sufficiently to remove the organic solvent, thereby forming the light absorption layer.

[0348] SiO was alternately laminated on the surface of the light absorption layer by vapor deposition 2 and TiO 2 , thereby forming the dielectric multilayer film X3.

[0349] The filter of Example 5 was manufactured in the above manner.

[0350] <Example 6: Filter>

[0351] SiO was alternately laminated on one main surface of the glass substrate (glass A) by vapor deposition 2 and TiO 2 , thereby forming the dielectric multilayer film Y1.

[0352] A resin solution was coated on the other main surface of the glass substrate with the same composition as the light absorption layer 1, and heated sufficiently to remove the organic solvent, thereby forming the light absorption layer.

[0353] SiO was alternately laminated on the surface of the light absorption layer by vapor deposition2 and TiO 2 , thus forming the dielectric multilayer film Y3.

[0354] The filter of Example 6 was manufactured in the above manner.

[0355] The compositions of the dielectric multilayer films A1 to A3, the dielectric multilayer films B1 to B3, and the dielectric multilayer films C1 to C3 are shown in Tables 2 to 10 below. It should be noted that the order of the numbers (No.) corresponds to the stacking order.

[0356] [Table 2]

[0357]

[0358] [Table 3]

[0359]

[0360] [Table 4]

[0361]

[0362] [Table 5]

[0363]

[0364] [Table 6]

[0365]

[0366] [Table 7]

[0367]

[0368] [Table 8]

[0369]

[0370] [Table 9]

[0371]

[0372] [Table 10]

[0373]

[0374] For each of the filters obtained in the above manner, the spectral transmittance curve at an incident angle of 0 degrees and the spectral reflectance curves at incident angles of 5 degrees and 40 degrees were measured in the wavelength range of 350 nm to 1200 nm using an ultraviolet-visible spectrophotometer.

[0375] Each of the characteristics shown in Table 12 below was calculated from the obtained spectral characteristic data.

[0376] In addition, the spectral transmittance and reflectance curves of the filters in Example 1 and Example 5 are respectively shown in Figures 4 to 9 .

[0377] It should be noted that Examples 1 to 4 are examples, and Examples 5 to 6 are comparative examples.

[0378] [Table 11]

[0379]

[0380] [Table 12]

[0381]

[0382] From the above results, it can be seen that for the filters of Examples 1 to 4 having the dielectric multilayer films 1 to 3, even at high incident angles, the reflection characteristics of light with wavelengths of 1300 nm to 1500 nm and 750 nm to 900 nm are both excellent, and the shielding properties of light with wavelengths of 350 nm to 400 nm are also both excellent.

[0383] On the other hand, for the filter of Example 5 that does not have the dielectric multilayer films 1 and 3 that satisfy the specified necessary conditions, the reflection characteristics of light with wavelengths of 1300 nm to 1500 nm are small, and the shielding properties of light with wavelengths of 350 nm to 400 nm are also insufficient.

[0384] In addition, for the filter of Example 6 that does not have the dielectric multilayer film 2, the reflection characteristics of light with wavelengths of 1300 nm to 1500 nm and 750 nm to 900 nm and the shielding properties of light with wavelengths of 350 nm to 400 nm are all insufficient.

[0385] The present invention has been described in detail with reference to specific embodiments, but various changes and modifications can be made without departing from the spirit and scope of the present invention, which will be obvious to those skilled in the art. This application is based on the Japanese Patent Application (Japanese Patent Application No. 2023-210429) filed on December 13, 2023, and its content is incorporated herein by reference.

[0386] Industrial Applicability

[0387] The filter of the present embodiment has excellent transmittance of visible light and specific near-infrared light even at high incident angles, and excellent shielding properties of other near-infrared light. It is useful in applications such as imaging devices such as cameras and sensors for conveyors, which have been promoted to have higher performance in recent years.

Claims

1. A filter, comprising, in sequence, a dielectric multilayer film (1), a glass substrate, a dielectric multilayer film (2), a light absorption layer and a dielectric multilayer film (3), wherein: The light absorbing layer comprises a near infrared absorbing pigment, The filter satisfies all of the following spectral characteristics (i-1) to (i-6): (i-1) When one principal surface is taken as the incident direction, the average reflectivity of light with a wavelength of 1300 nm to 1500 nm is 90% or more at an incident angle of 5 degrees and is 90% or more at an incident angle of 40 degrees; (i-2) When one principal surface is taken as the incident direction, the maximum reflectivity of light with a wavelength of 1300 nm to 1500 nm is 95% or more at an incident angle of 5 degrees and is 95% or more at an incident angle of 40 degrees; (i-3) When the other principal surface is taken as the incident direction, the average reflectivity of light with a wavelength of 750 nm to 900 nm is 30% or more at an incident angle of 5 degrees and is 30% or more at an incident angle of 40 degrees; (i-4) When the other principal surface is taken as the incident direction, the maximum reflectivity of light with a wavelength of 750 nm to 900 nm is 80% or more at an incident angle of 5 degrees and is 70% or more at an incident angle of 40 degrees; (i-5) The average transmittance of light with a wavelength of 350 nm to 400 nm is 1% or less at an incident angle of 0 degrees and 2% or less at an incident angle of 40 degrees; (i-6) The maximum transmittance of light with a wavelength of 350 nm to 400 nm is 2% or less at an incident angle of 0 degrees and is 3% or less at an incident angle of 40 degrees.

2. The optical filter according to claim 1, wherein: At least one of the dielectric multilayer films (1) to (3) satisfies all of the following characteristics (iiB-1) to (iiB-3): (iiB-1) The total number of layers is 1 to 60; (iiB-2) comprising a high refractive index layer HB having a refractive index of 1.8 to 2.5 and a low refractive index layer LB having a refractive index of 1.4 to 1.6, wherein the ratio of the total physical film thickness of the high refractive index layer HB to the total physical film thickness of the low refractive index layer LB is 0.2 to 0.8; (iiB-3) When the high refractive index layer having a QWOT of 1.0 or more is set as the HB1 layer, and the low refractive index layer having a QWOT of 1.0 or more is set as the LB1 layer, The layer between the HB1 layer and the LB1 layer is the MB1 layer, the MB1 layer includes a single layer or multiple layers, and the QWOT of each of all these layers is less than 1.0, It has one or more layered structures represented by the following formula: (HB1 layer / MB1 layer / LB1 layer).

3. The optical filter according to claim 1, wherein: At least one of the dielectric multilayer films (1) to (3) satisfies all of the following characteristics (iiA-1) to (iiA-3): (iiA-1) The total number of layers is 1 to 80; (iiA-2) comprising a high refractive index layer HA having a refractive index of 1.8 to 2.5 and a low refractive index layer LA having a refractive index of 1.4 to 1.6, wherein the ratio of the total physical film thickness of the high refractive index layer HA to the total physical film thickness of the low refractive index layer LA is 0.3 to 0.8; (iiA-3) When the QWOT of the high refractive index layer is 1.0 or more and the nth layer close to the glass substrate is set as HA n layer, wherein the QWOT in the low refractive index layer is greater than 1.0 and is adjacent to the HA layer n Then the layer close to the glass substrate is set as LA n Layer, The HA n Layer with the LA n The layers between the layers are MA 2n-1 Layer, the MA 2n-1 The layer contains a single layer or multiple layers and the total QWOT is less than 1, The LA n The HA layer with QWOT greater than 1.0 and the n+1th HA layer close to the glass substrate n+1 The layers between the layers are MA 2n Layer, the MA 2n The layer contains a single layer or multiple layers and the total QWOT is less than 1, It has a repeating structure as shown below (n is a natural number greater than 2): (HA1 layer / MA1 layer / LA1 layer / MA2 layer)...(HA n Layer / MA 2n-1 Layer / LA n Layer / MA 2n layer).

4. The optical filter according to claim 1, wherein: At least one of the dielectric multilayer films (1) to (3) satisfies all of the following characteristics (iiC-1) to (iiC-3): (iiC-1) The total number of stacking layers is 1 to 60; (iiC-2) comprising a high refractive index layer HC having a refractive index of 1.8 to 2.5, and a low refractive index layer LC having a refractive index of 1.4 to 1.6, wherein a ratio of a total physical film thickness of the high refractive index layer HC to a total physical film thickness of the low refractive index layer LC is 0.5 to 0.9, and a ratio of a total QWOT of the high refractive index layer HC to a total QWOT of the low refractive index layer LC is 1.1 to 1.5; (iiC-3) has a stacked structure as shown below: (HC2 layer / LC2 layer / HC2 layer) / MC1 layer / (LC1 layer / HC1 layer / LC1 layer) / MC1 layer / (HC2 layer / LC2 layer / HC2 layer) The HC1 layer and the HC2 layer are each independently a high refractive index layer having a QWOT of 1.0 or more; The LC1 layer and the LC2 layer are each independently a low refractive index layer having a QWOT of 1.0 or more; Each MC1 layer independently has a total QWOT of 1 or less and is composed of a single layer or a plurality of layers.

5. The optical filter according to claim 1, wherein: The glass substrate contains ytterbium.

6. The optical filter according to claim 1, wherein: The filter satisfies the following spectral characteristics (i-7): When any of the main surfaces is taken as the incident direction, the absorption loss at a wavelength of Xnm is defined as follows: X : (Absorption loss X )[%]=100-(transmittance at incident angle 0 degrees)-(reflectivity at incident angle 5 degrees) (i-7) Absorption loss in the wavelength range of 430nm to 1100nm 430-1100 The integral value is 10000 or more.

7. The optical filter according to claim 1, wherein: The glass substrate contains, in terms of mole % based on oxides: 0.1 mol% to 50 mol% SiO2, 15 mol% to 40 mol% B2O3, 0 mol% to 15 mol% P2O5, and 20 mol % to 60 mol % Yb2O3.

8. The optical filter according to claim 1, wherein: The near infrared absorbing pigment includes a pigment having a maximum absorption wavelength in the wavelength range of 680 nm to 800 nm. The light absorbing layer satisfies all of the following spectral characteristics (iii-1) to (iii-2): (iii-1) When the shortest wavelength at which the internal transmittance is 30% in the spectral transmittance curve at wavelengths of 650 nm to 720 nm is set to λ A_VIS(30%) , the shortest wavelength at which the internal transmittance is 30% in the spectral transmittance curve of wavelengths 720nm to 1000nm is set as λ A_IR(30%) When , the following relationship is satisfied: |l A_IR(30%) -l A_VIS(30%) |≥100nm (iii-2) When the optical density at a wavelength of 720 nm is set to OD _720 When , the following relationship is satisfied: OF _720 ≥2.0。 9. The optical filter according to claim 1, wherein: The filter satisfies all of the following spectral characteristics (i-8) to (i-11): (i-8) When one principal surface is taken as the incident direction, the average reflectivity of light with a wavelength of 420 nm to 650 nm is 5% or less at an incident angle of 5 degrees and is 5% or less at an incident angle of 40 degrees; (i-9) When one principal surface is taken as the incident direction, the maximum reflectivity of light having a wavelength of 420 nm to 650 nm is 10% or less at an incident angle of 5 degrees and is 15% or less at an incident angle of 40 degrees; (i-10) When one principal surface is taken as the incident direction, the average reflectivity of light having a wavelength of 1030 nm to 1150 nm is 9% or less at an incident angle of 5 degrees and is 10% or less at an incident angle of 40 degrees; (i-11) When one principal surface is taken as the incident direction, the maximum reflectivity of light having a wavelength of 1030 nm to 1150 nm is 10% or less at an incident angle of 5 degrees and is 15% or less at an incident angle of 40 degrees.

10. The optical filter according to claim 1, wherein: The filter satisfies all of the following spectral characteristics (i-12) to (i-15): (i-12) When the other principal surface is taken as the incident direction, the average reflectivity of light with a wavelength of 420 nm to 650 nm is 5% or less at an incident angle of 5 degrees and is 5% or less at an incident angle of 40 degrees; (i-13) When the other principal surface is taken as the incident direction, the maximum reflectivity of light having a wavelength of 420 nm to 650 nm is 10% or less at an incident angle of 5 degrees and is 15% or less at an incident angle of 40 degrees; (i-14) When the other principal surface is taken as the incident direction, the average reflectivity of light with a wavelength of 1030 nm to 1150 nm is 9% or less at an incident angle of 5 degrees and is 10% or less at an incident angle of 40 degrees; (i-15) When the other principal surface is taken as the incident direction, the maximum reflectivity of light having a wavelength of 1030 nm to 1150 nm is 10% or less at an incident angle of 5 degrees and is 15% or less at an incident angle of 40 degrees.

11. An imaging device, wherein: The imaging device comprises the optical filter according to any one of claims 1 to 10.

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