Optical filter

Abstract

The present invention relates to an optical filter comprising a transparent substrate and a dielectric multilayer film provided on at least one principal surface of the transparent substrate, wherein, when transmittance in a wavelength range of 350 to 1200 nm is output in 1 nm units, all of characteristics (i-1) to (i-3) are satisfied, and reflectance when light is incident from a dielectric multilayer film side satisfies all of characteristics (ii-1) to (ii-4) and (iii-1) to (iii-4).

Description

Optical filter

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

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

[0003] Examples of such optical filters include reflective filters that utilize light interference to reflect light to be blocked by having a dielectric multilayer film in which multiple dielectric thin films with different refractive indices are laminated on one or both sides of a transparent substrate, absorbing filters that absorb light to be blocked by using glass or dyes that absorb light in a specific wavelength range, and filters that combine reflective and absorbing types. Patent Document 1 describes an optical filter comprising a transparent substrate and three or more thin-film laminated structures that limit the transmission of light in a predetermined wavelength range within the near-infrared wavelength region. Patent Document 2 describes an optical filter comprising a substrate that transmits light in at least the visible wavelength range and an infrared reflective layer composed of a repeating laminated film consisting of a high refractive index film and a low refractive index film.

[0004] International Publication No. 2019 / 189039, International Publication No. 2014 / 104370

[0005] Optical filters with dielectric multilayer films suffer from a problem where the spectral transmittance curve changes with the angle of incidence because the optical thickness of the dielectric multilayer film changes with the angle of incidence of light. This problem tends to be more pronounced as the angle of incidence of light increases. For example, as the angle of incidence of light increases, the reflection characteristics shift to shorter wavelengths, which may result in a decrease in reflection characteristics in the near-infrared light region that is intended to be shielded. In addition, 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. This can lead to a problem where the amount of visible light captured changes at high angles of incidence, resulting in a decrease in image reproducibility. 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.

[0006] According to the optical filter described in Patent Document 1, it is said that even with light at a large angle of incidence, the visible light transmittance is high and the dependence on the angle of incidence is low. However, when the angle of incidence of light is as large as 60°, there is a problem in that the infrared light cut-off characteristics are not sufficient. The optical filter described in Patent Document 2 also has excellent infrared light cut-off characteristics when the angle of incidence of light is large, but when the angle of incidence of light is as large as 60°, there is a problem in that the infrared light cut-off characteristics are not sufficient. Thus, the optical filters described in Patent Document 1 and Patent Document 2 had room for improvement in terms of ripple generation in the visible light region and near-infrared light reflection characteristics at high angles of incidence. The present invention aims to provide an optical filter that suppresses ripple generation in the visible light region even at large angles of incidence of light, and has good near-infrared light reflection characteristics.

[0007] The present invention provides an optical filter having the following configuration: an optical filter comprising a transparent substrate and a dielectric multilayer film provided on at least one main surface of the transparent substrate, wherein the optical filter satisfies all of the following characteristics (i-1) to (i-3) when outputting transmittance in units of 1 nm in the wavelength range of 350 to 1200 nm, and satisfies all of the following characteristics (ii-1) to (ii-4) and (iii-1) to (iii-4) when light is incident on the dielectric multilayer film side. (i-1) At wavelengths of 900 to 1000 nm, there are 20 or more particles with a transmittance of 0.15% or less at an incident angle of 0 degrees. (i-2) At wavelengths of 900 to 1000 nm, there are 23 or more particles with a transmittance of 0.3% or less at an incident angle of 30 degrees. (i-3) At wavelengths of 750 to 850 nm, there are 22 or more particles with a transmittance of 1% or less at an incident angle of 60 degrees. (ii-1) At wavelengths of 420 to 750 nm, the average reflectance at an incident angle of 5 degrees is 3% or less. (ii-2) At wavelengths of 420 to 750 nm, the maximum reflectance at an incident angle of 5 degrees is 10% or less. (ii-3) At wavelengths of 420 to 690 nm, the average reflectance at an incident angle of 60 degrees is 15% or less. (ii-4) At wavelengths of 420 to 690 nm, the maximum reflectance at an incident angle of 60 degrees is 40% or less. (iii-1) Average reflectance of 99.5% or higher at wavelengths of 900-1000 nm and an incident angle of 5 degrees. (iii-2) Minimum reflectance of 98% or higher at wavelengths of 900-1000 nm and an incident angle of 5 degrees. (iii-3) Average reflectance of 94% or higher at wavelengths of 750-850 nm and an incident angle of 60 degrees. (iii-4) Minimum reflectance of 84% or higher at wavelengths of 750-850 nm and an incident angle of 60 degrees.

[0008] According to the present invention, an optical filter can be provided that suppresses the generation of ripple in the visible light region even when the angle of incidence of light is large, and also exhibits good reflection characteristics for near-infrared light.

[0009] Figure 1 is a schematic cross-sectional view showing an example of an optical filter according to one embodiment. Figure 2 is a schematic cross-sectional view showing another example of an optical filter according to one embodiment. Figure 3 is a diagram showing the spectral transmittance curve of glass B. Figure 4 is a diagram showing the spectral transmittance curve (700-1000 nm) of the optical filter of Example 1. Figure 5 is a diagram showing the spectral reflectance curve (350-1000 nm) of the optical filter of Example 1. Figure 6 is a diagram showing the spectral transmittance curve (700-1000 nm) of the optical filter of Example 2. Figure 7 is a diagram showing the spectral reflectance curve (350-1000 nm) of the optical filter of Example 2. Figure 8 is a diagram showing the spectral transmittance curve (700-1000 nm) of the optical filter of Example 3. Figure 9 is a diagram showing the spectral transmittance curve (350-1000 nm) of the optical filter of Example 3. Figure 10 is a diagram showing the spectral reflectance curve (350-1000 nm) of the optical filter of Example 3. Figure 11 shows the spectral transmittance curve (700-1000 nm) of the optical filter in Example 4. Figure 12 shows the spectral transmittance curve (700-1000 nm) of the optical filter in Example 5. Figure 13 shows the spectral transmittance curve (700-1000 nm) of the optical filter in Example 6. Figure 14 shows the spectral transmittance curve (700-1000 nm) of the optical filter in Example 7.

[0010] 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, a compound represented by formula (I) will be referred to as compound (I). The same applies to compounds represented by other formulas. A dye consisting of compound (I) will also be referred to as dye (I), and the same applies to other dyes. Furthermore, a group represented by formula (I) will also be referred to as group (I), and the same applies to groups represented by other formulas.

[0011] 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.

[0012] Spectral characteristics can be measured using a UV-Vis spectrophotometer. In this specification, the "~" indicating a numerical range includes both upper and lower limits.

[0013] <Optical Filter> An optical filter according to one embodiment of the present invention (hereinafter also referred to as "this filter") comprises a transparent substrate and a dielectric multilayer film provided on at least one main surface of the transparent substrate. Due to the reflective properties of the dielectric multilayer film, the optical filter as a whole can achieve excellent transmittance in the visible light region and excellent shielding in the near-infrared light region.

[0014] An example of the configuration of this filter will be explained using the drawings. Figures 1 and 2 are schematic cross-sectional views showing an example of an optical filter according to one embodiment.

[0015] The optical filter 1A shown in Figure 1 is an example comprising a transparent substrate 10 and a dielectric multilayer film 20A provided on one main surface side of the transparent substrate 10.

[0016] The optical filter 1B shown in Figure 2 is an example comprising a transparent substrate 10, a dielectric multilayer film 20A provided on one main surface side of the transparent substrate 10, a dielectric multilayer film 20B provided on the other main surface side of the transparent substrate 10, a light-absorbing layer 30 provided on the surface of the dielectric multilayer film 20B, and a dielectric multilayer film 20C provided on the surface of the light-absorbing layer 30.

[0017] When this optical filter outputs transmittance in 1 nm units in the wavelength range of 350 to 1200 nm, it satisfies all of the following characteristics (i-1) to (i-3): (i-1) At wavelengths of 900 to 1000 nm, there are 20 or more instances where the transmittance at an incident angle of 0 degrees is 0.15% or less. (i-2) At wavelengths of 900 to 1000 nm, there are 23 or more instances where the transmittance at an incident angle of 30 degrees is 0.3% or less. (i-3) At wavelengths of 750 to 850 nm, there are 22 or more instances where the transmittance at an incident angle of 60 degrees is 1% or less.

[0018] Satisfying all of the characteristics of (i-1) to (i-3) means that near-infrared light can be reliably cut regardless of the incident angle of light. As a result, ripples in the visible light region can be suppressed even at a high incident angle, and the reflection characteristics of near-infrared light can be maintained to block near-infrared light even at a high incident angle. Consequently, the color reproducibility of the solid-state imaging device can be enhanced.

[0019] In this specification, the above-mentioned "number" more specifically means the number of wavelengths within a specific range of transmittance when the corresponding wavelength range is divided into 1-nm units. For example, in the case of characteristic (i-1), it means that among 101 wavelengths within the wavelength range of 900 to 1000 nm, the number of wavelengths with the above-mentioned specific transmittance is 20 or more.

[0020] In characteristic (i-1), the number of wavelengths with a transmittance of 0.15% or less at an incident angle of 0 degrees is preferably 40 or more, and more preferably 50 or more. In characteristic (i-2), the number of wavelengths with a transmittance of 0.3% or less at an incident angle of 30 degrees is preferably 25 or more, and more preferably 30 or more. In characteristic (i-3), the number of wavelengths with a transmittance of 1% or less at an incident angle of 60 degrees is preferably 25 or more, and more preferably 30 or more.

[0021] To satisfy characteristics (i-1) to (i-3), for example, it includes providing a dielectric multilayer film having a repeating laminated structure represented by (a ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ ), ｎ providing a dielectric multilayer film having a repeating laminated structure represented by at least one selected from (H / L) [[ID=**28**]] ｎ [[ID=**29**]] (0.5H / L / 0.5H) [[ID=**30**]] ｎ [[ID=**31**]] and (0.5L / H / 0.5L) [[ID=**32**]] ｎ [[ID=**33**]], etc. (a [[ID=**34**]] ｎ [[ID=**35**]]Q [[ID=**36**]] Ｈ [[ID=**37**]] / b [[ID=**38**]] ｎ [[ID=**39**]]Q [[ID=**40**]] Ｌ [[ID=**41**]] / c [[ID=**42**]] ｎ [[ID=**43**]]Q [[ID=**44**]] Ｈ [[ID=**45**]] / d [[ID=**46**]] ｎ [[ID=**47**]]Q [[ID=**48**]] Ｌ [[ID=**49**]])ｎ The repeating layered structure represented by will be described later. H is a high refractive index film, and L is a low refractive index film; for example, (H / L) ｎ This means that it has n repeating layered structures in which high refractive index films (H) and low refractive index films (L) are alternately stacked. Also, (0.5H / L / 0.5H) ｎ The numbers before H and L indicate how many times the optical film thickness of the layer is compared to the design's reference wavelength (λ = 500 nm), where λ is the reference wavelength of the design. The symbol n indicates that the configuration in parentheses is repeated n times.

[0022] When light is incident on this filter from the dielectric multilayer film side, it satisfies all of the following characteristics: (ii-1) to (ii-4) and (iii-1) to (iii-4). Furthermore, if this filter has dielectric multilayer films on both sides of a transparent substrate, the direction of light incidence is determined by comparing the case where light is incident from one side with the case where light is incident from the other side, and is based on the side with lower reflectivity at wavelengths of 420 to 690 nm and higher reflectivity at wavelengths of 750 to 1000 nm. (ii-1) Average reflectance of 3% or less at wavelength 420-750 nm and incident angle of 5 degrees (ii-2) Maximum reflectance of 10% or less at wavelength 420-750 nm and incident angle of 5 degrees (ii-3) Average reflectance of 15% or less at wavelength 420-690 nm and incident angle of 60 degrees (ii-4) Maximum reflectance of 40% or less at wavelength 420-690 nm and incident angle of 60 degrees (iii-1) Average reflectance of 99.5% or more at wavelength 900-1000 nm and incident angle of 5 degrees (iii-2) Minimum reflectance of 98% or more at wavelength 900-1000 nm and incident angle of 5 degrees (iii-3) Average reflectance of 94% or more at wavelength 750-850 nm and incident angle of 60 degrees (iii-4) Minimum reflectance of 84% or more at wavelength 750-850 nm and incident angle of 60 degrees

[0023] Satisfying characteristics (ii-1) to (ii-4) means that the reflectivity in the visible light region is low even at high incident angles, and satisfying these characteristics can suppress ripple generation in the visible light region. In characteristic (ii-1), the average reflectivity at an incident angle of 5 degrees is more preferably 2.7% or less. In characteristic (ii-2), the maximum reflectivity at an incident angle of 5 degrees is more preferably 9.9% or less. In characteristic (ii-3), the average reflectivity at an incident angle of 60 degrees is more preferably 12% or less. In characteristic (ii-4), the maximum reflectivity at an incident angle of 60 degrees is more preferably 37% or less.

[0024] Satisfying characteristics (iii-1) to (iii-4) means that the near-infrared light reflection characteristics are maintained, and if these characteristics are satisfied, near-infrared light can be blocked. In characteristic (iii-1), the average reflectance at an incident angle of 5 degrees is more preferably 99.6% or higher. In characteristic (iii-2), the minimum reflectance at an incident angle of 5 degrees is more preferably 98.5% or higher. In characteristic (iii-3), the average reflectance at an incident angle of 60 degrees is more preferably 94.3% or higher. In characteristic (iii-4), the minimum reflectance at an incident angle of 60 degrees is more preferably 84.3% or higher.

[0025] In order to satisfy the characteristics of (ii-1) to (ii-4) and (iii-1) to (iii-4), for example, (a, as described below) ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ ) ｎ It comprises a dielectric multilayer film having a repeating stacked structure represented by (0.5H / L / 0.5H). ｎ , and (0.5L / H / 0.5L) ｎ Examples include comprising a dielectric multilayer film having a repeating stacked structure represented by at least one of the following.

[0026] <Transparent Substrate> The transparent substrate in this filter is not limited as long as it has transparency that allows visible light to pass through and can support a dielectric multilayer film. From the viewpoint of effectively blocking near-infrared light, it is preferable that the transparent substrate has near-infrared light absorbing properties. The substrate material may be either an organic or inorganic material.

[0027] Examples of organic materials include transparent resins, such as polyester resins, acrylic resins, epoxy resins, ene-thiol resins, polycarbonate resins, polyether resins, polyarylate resins, polysulfone resins, polyethersulfone resins, poly-paraphenylene resins, polyarylene ether phosphine oxide resins, polyamide resins, polyimide resins, polyamide-imide resins, polyolefin resins, cyclic olefin resins, polyurethane resins, and polystyrene resins. These resins may be used individually or in mixtures of two or more.

[0028] As inorganic materials, glass and crystalline materials are preferred. As glass, transparent glass or near-infrared light absorbing glass may be used. Examples of transparent glass include soda-lime glass, borosilicate glass, alkali-free glass, and quartz glass. Examples of near-infrared light absorbing glass include phthalate-based glass and phosphate-based glass containing copper ions. Examples of crystalline materials include birefringent crystals such as quartz, lithium niobate, and sapphire.

[0029] As for the transparent substrate, an inorganic material substrate is preferred, and a glass substrate is particularly preferred, from the viewpoint of shape stability related to long-term reliability such as spectral characteristics and mechanical properties, as well as handling during filter manufacturing.

[0030] <Dielectric Multilayer Film> This filter is provided with a dielectric multilayer film on one main surface side of the transparent substrate. Preferably, such dielectric multilayer film is designed as a reflective film that reflects near-infrared light (hereinafter also referred to as "NIR reflective film").

[0031] A dielectric multilayer film is a stack of dielectric films with different refractive indices. More specifically, it can consist of a dielectric film with a low refractive index, a dielectric film with a medium refractive index, or a dielectric film with a high refractive index, with two or more of these films stacked together. By combining several dielectric films with different spectral characteristics, the reflection characteristics can be adjusted when transmitting or selecting a desired wavelength band.

[0032] The dielectric multilayer film includes a high refractive index film with a refractive index of 2.0 or higher at a wavelength of 500 nm and a low refractive index film with a refractive index of 1.6 or lower at a wavelength of 500 nm, and the QWOT of the high refractive index film at a wavelength of 500 nm is Q Ｈ QWOT of the low refractive index film at a wavelength of 500 nm is Q Ｌ When that happens, (a ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ ) ｎ It is preferable to have a repeating layered structure represented by where n is a natural number greater than or equal to 9. ｎ is 2.00 or higher, b ｎ is 0.40 or more and 0.90 or less, c ｎ is 0.20 or more and 0.50 or less, d ｎ It is between 0.40 and 0.90.

[0033] a ｎ , b ｎ , c ｎ d ｎ This is a coefficient in each base unit, and it represents how many times the physical film thickness of the film in each base unit is compared to QWOT (optical film thickness at 1 / 4 wavelength). Therefore, a ｎ Q Ｈ , b ｎ Q Ｌ , c ｎ Q Ｈ d ｎ Q Ｌ This indicates the optical film thickness of each film.

[0034] (a ｎ Q Ｈ / b ｎQ Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ By having a repeating laminated structure of 9 or more of (Q Ｌ / c)(Q Ｈ / d)(Q Ｌ ), the visible light reflectance is suppressed to suppress the occurrence of ripples in the visible light region, and the reflection characteristics of near-infrared light are also easily obtained.

[0035] n is more preferably 11 or more, preferably 25 or less, and more preferably 20 or less. a ｎ is more preferably 2.10 or more, even more preferably 2.​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​include. Other commercially available products include those manufactured by Canon Optron, such as OS50 (Ti ３ O ５ ), OS10 (Ti ４ O ７ ), OA500 (a mixture of Ta ２ O ５ and ZrO ２ ), OA600 (a mixture of Ta ２ O ５ and TiO ２ ). Among these, TiO ２ is preferred in terms of reproducibility, stability, etc. in film formation properties, refractive index, etc.

[0038] The low refractive index film preferably has a refractive index at a wavelength of 500 nm of 1.3 or more and 1.6 or less, more preferably 1.45 or more and 1.5 or less. Examples of materials constituting the low refractive index film include SiO ２ , SiO ｘ N ｙ、 MgF ２ , etc. Other commercially available products include those manufactured by Canon Optron, such as S4F, S5F (a mixture of SiO ２ and AlO ２ ). Among these, SiO ２ is preferred in terms of reproducibility, stability, economy, etc. in film formation properties.

[0039] The dielectric multilayer film may have a dielectric film in addition to the repeating laminated structure represented by (a ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ ). For example, it may have a high refractive index film or a low refractive index film that does not form a repeating laminated structure, or it may have a medium refractive index film. The medium refractive index film preferably has a refractive index at a wavelength of 500 nm of more than 1.5 and less than 1.8, more preferably 1.55 or more and less than 1.8. Examples of materials constituting the medium refractive index film include ZrO ２ , Nb ２ O ５ ​​​​​​, HfO ２ Also, the OM-4 and OM-6 (Al) sold by Canon Optron Corporation. ２ O ３ and ZrO ２ Examples include a mixture of ), OA-100, H4 and M2 (alumina antania) sold by Merck, etc. Of these, Al is chosen based on its film-forming properties, reproducibility in refractive index, stability, etc. ２ O ３ Compounds of the system and Al ２ O ３ and ZrO ２ A mixture of these is preferred.

[0040] In this filter, the dielectric multilayer film is the above (a ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ ) ｎ In addition to the repeating stacked structure represented by (e ｍ Q Ｈ / f ｍ Q Ｌ / g ｍ Q Ｈ / h ｍ Q Ｌ ) ｍ It may have a repeating layered structure represented by where m is a natural number of 1 or more. (a ｎ +e ｍ The average value of (b) is less than 2.40, ｎ +f ｍ The average value of (c) is between 0.40 and 0.90, and ｎ +g ｍ The average value of ) is 0.20 or more and 0.50 or less, (d ｎ +h ｍ The average value of (a) is 0.40 or more and 0.90 or less. Such dielectric multilayer films are preferable because they can lower the transmittance of light with wavelengths of 750 nm to 850 nm when the angle of incidence of light is high (for example, 60°). Note that the repeated stacking structure in the dielectric multilayer film is as described above (a) ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ QＨ / d ｎ Q Ｌ ) ｎ A repeating stacked structure represented by (e ｍ Q Ｈ / f ｍ Q Ｌ / g ｍ Q Ｈ / h ｍ Q Ｌ ) ｍ In the case of a repeating laminated structure represented by , it is permissible to provide a dielectric film between the transparent substrate and the repeating laminated structure. Similarly, it is permissible to provide a dielectric film on the outermost layer on the air side of the repeating laminated structure. Such dielectric films are provided, for example, to improve the weather resistance of the substrate or to suppress ripple in the visible wavelength range, and are preferably dielectric multilayer films with six or fewer layers. ｎ +e ｍ The average value of ) is the average of all a ｎ and all e ｍ (b) is the value obtained by summing the two and dividing the sum by (n + m). ｎ +f ｍ ) average value, (c ｎ +g ｍ ) average value, (d ｎ +h ｍ The average value of ) is calculated similarly. ｍ , f ｍ , g ｍ , h ｍ This is a coefficient in each base unit, and it represents how many times the physical film thickness of the film in each base unit is compared to QWOT (optical film thickness at 1 / 4 wavelength). Therefore, e ｍ Q Ｈ , f ｍ Q Ｌ , g ｍ Q Ｈ , h ｍ Q Ｌ This indicates the optical film thickness of each film.

[0041] In this filter, the repeated stacking structure in the dielectric multilayer film is as described above (a ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ Q Ｈ / dｎ Q Ｌ ) ｎ It is preferable that the dielectric multilayer film consists only of the repeating stacked structure represented by (a). Such a dielectric multilayer film is preferable because it can increase the reflectivity of light with wavelengths of 750 nm to 850 nm when the angle of incidence of light is high (for example, 60°). ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ ) ｎ In the case of only the repeating laminated structure represented by [the formula], it is permissible to provide a dielectric film between the transparent substrate and the repeating laminated structure. Similarly, it is permissible to provide a dielectric film on the outermost layer on the air side of the repeating laminated structure. Such a dielectric film is provided, for example, to improve the weather resistance of the substrate or to suppress ripple in the visible wavelength range, and is preferably a dielectric multilayer film with six or fewer layers.

[0042] The number of layers of dielectric multilayer films is preferably 1 to 60, more preferably 30 to 60, and even more preferably 40 to 60. The total thickness (physical thickness) of the dielectric multilayer films is preferably 100 nm or more, more preferably 300 nm or more, from the viewpoint of suppressing material degradation, and is preferably 5 μm or less from the viewpoint of productivity and suppression of reflection ripple in the visible light region.

[0043] This filter is the above (a ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ ) ｎ Repeating stacked structures represented by (e ｍ Q Ｈ / f ｍ Q Ｌ / g ｍ Q Ｈ / h ｍ Q Ｌ ) ｍIn addition to the dielectric multilayer film having the repeating stacked structure represented by the formula, another dielectric multilayer film may be provided on the other main surface side of the transparent substrate. From the viewpoint of reducing ripple generation in the visible light region, it is preferable that the other dielectric multilayer film be designed as, for example, a near-infrared anti-reflection layer (NIR anti-reflection layer).

[0044] The total number of layers of other dielectric multilayer films is preferably 25 layers or less, more preferably 20 layers or less, even more preferably 17 layers or less, and also preferably 10 layers or more. In order to suppress reflection in the visible wavelength band even when the incident angle changes, a film with low reflectivity across the entire wavelength band is preferred, rather than a film that reflects specific wavelengths. Furthermore, the thickness (physical thickness) of the other dielectric multilayer films is preferably 200 μm to 600 μm in total.

[0045] For forming dielectric multilayer films, vacuum deposition processes such as CVD, sputtering, and vacuum evaporation, as well as wet deposition processes such as spraying and dipping, can be used.

[0046] <Light Absorption Layer> This filter may include a light absorption layer comprising a resin and a near-infrared light-absorbing dye. This allows the light-shielding properties of regions that are difficult to shield with the reflective properties of the dielectric multilayer film to be compensated for by the absorption properties. The light absorption layer may be provided on either main surface side of the transparent substrate, but it is preferable to provide it on the other main surface side of the transparent substrate, opposite to the dielectric multilayer film. As the near-infrared light-absorbing dye, a dye having a maximum absorption wavelength in the 680 to 800 nm wavelength range in dichloromethane is preferred. Furthermore, from the viewpoint of broadly absorbing the near-infrared region, it is preferable to combine two dyes with different maximum absorption wavelengths that are in the 680 to 800 nm range, preferably a dye with a maximum absorption wavelength of 680 to 740 nm and a dye with a maximum absorption wavelength of 740 to 800 nm. The light absorption layer is also preferably a resin film containing the dye and resin.

[0047] As the NIR dye, at least one selected from the group consisting of squarylium dye, cyanine dye, phthalocyanine dye, naphthalocyanine dye, dithiol metal complex dye, azo dye, polymethine dye, phthalide dye, naphthoquinone dye, anthraquinone dye, indophenol dye, pyrylium dye, thiopyrillium dye, croconium dye, tetradehydocholine dye, triphenylmethane dye, aminium dye, and diimmonium dye is preferred.

[0048] The NIR dye preferably contains at least one dye selected from squarylium dye, phthalocyanine dye, and cyanine dye. Among these NIR dyes, squarylium dye and cyanine dye are preferred from a spectroscopic viewpoint, and phthalocyanine dye is preferred from a durability viewpoint.

[0049] The content of the NIR dye in the light-absorbing layer is preferably 0.1 to 25 parts by mass, more preferably 0.3 to 15 parts by mass, per 100 parts by mass of resin. When two or more compounds are combined, the above content is the sum of the individual compounds.

[0050] The light-absorbing layer may contain other dyes besides the NIR dyes mentioned above. Preferably, the other dyes are those having a maximum absorption wavelength of 370 to 440 nm in the resin (UV dyes). This allows for efficient shielding of the near-ultraviolet light region.

[0051] 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.

[0052] The resin used in the light-absorbing layer 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 spectral characteristics, glass transition temperature (Tg), and adhesion of the light-absorbing layer, one or more resins selected from polyimide resin, polycarbonate resin, polyester resin, and acrylic resin are preferred.

[0053] When multiple compounds are used as NIR dyes or other dyes, they may be contained in the same light-absorbing layer, or they may each be contained in separate light-absorbing layers.

[0054] The light-absorbing layer 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 needed. The support may be a transparent substrate or a releaseable support used only when forming the light-absorbing layer. The solvent may be any dispersion medium or solvent that can stably disperse or dissolve the components.

[0055] Furthermore, the coating solution may contain surfactants to improve voids caused by minute bubbles, indentations caused by the adhesion of foreign matter, and repelling during the drying process. Additionally, methods such as immersion coating, cast coating, or spin coating can be used for applying the coating solution. If the coating solution contains raw material components of a transparent resin, further curing treatments such as thermosetting or photocuring are performed.

[0056] Furthermore, the light-absorbing layer can also be manufactured in film form by extrusion molding. The resulting film-like absorbing layer can be laminated onto a light-absorbing glass substrate and integrated by thermocompression bonding or the like to manufacture this filter.

[0057] The light-absorbing layer may be one layer or two or more layers within the optical filter. If there are two or more layers, each layer may have the same configuration or different configurations, and they may be formed on the surface of each dielectric multilayer film or two or more layers may be stacked on the surface of one of the dielectric multilayer films.

[0058] The thickness of the light-absorbing layer 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 light-absorbing layers, it is preferable that the total thickness of each light-absorbing layer is within the above range.

[0059] 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 of such infrared light is required.

[0060] <Imaging Apparatus> The imaging apparatus according to the embodiment of the present invention preferably comprises the optical filter according to the embodiment of the present invention described above. The imaging apparatus preferably further comprises a solid-state image sensor and an imaging lens. The optical filter according to this embodiment can be used, for example, by being placed between the imaging lens and the solid-state image sensor, or by being directly attached to the solid-state image sensor, imaging lens, etc. of the imaging apparatus via an adhesive layer. By equipping the apparatus with this filter, which has excellent transmittance of visible light, shielding properties for near-infrared light, and suppresses ripple in the visible light region even at high incidence angles, an imaging apparatus with excellent color reproduction even for light at high incidence angles can be obtained.

[0061] When mounting an optical filter in an imaging device, it is generally preferable to have the dielectric multilayer film facing the lens side.

[0062] As described above, the Specified Optical Filters, etc., are disclosed herein. [1] An optical filter comprising a transparent substrate and a dielectric multilayer film provided on at least one main surface of the transparent substrate, wherein the optical filter satisfies all of the following characteristics (i-1) to (i-3) when the transmittance in the wavelength range of 350 to 1200 nm is output in units of 1 nm, and the optical filter satisfies all of the following characteristics (ii-1) to (ii-4) and (iii-1) to (iii-4) when light is incident on the dielectric multilayer film side. (i-1) At wavelengths of 900 to 1000 nm, there are 20 or more particles with a transmittance of 0.15% or less at an incident angle of 0 degrees. (i-2) At wavelengths of 900 to 1000 nm, there are 23 or more particles with a transmittance of 0.3% or less at an incident angle of 30 degrees. (i-3) At wavelengths of 750 to 850 nm, there are 22 or more particles with a transmittance of 1% or less at an incident angle of 60 degrees. (ii-1) At wavelengths of 420 to 750 nm, the average reflectance at an incident angle of 5 degrees is 3% or less. (ii-2) At wavelengths of 420 to 750 nm, the maximum reflectance at an incident angle of 5 degrees is 10% or less. (ii-3) At wavelengths of 420 to 690 nm, the average reflectance at an incident angle of 60 degrees is 15% or less. (ii-4) At wavelengths of 420 to 690 nm, the maximum reflectance at an incident angle of 60 degrees is 40% or less. (iii-1) The average reflectance at a wavelength of 900 to 1000 nm and an incident angle of 5 degrees is 99.5% or higher. (iii-2) The minimum reflectance at a wavelength of 900 to 1000 nm and an incident angle of 5 degrees is 98% or higher. (iii-3) The average reflectance at a wavelength of 750 to 850 nm and an incident angle of 60 degrees is 94% or higher. (iii-4) The minimum reflectance at a wavelength of 750 to 850 nm and an incident angle of 60 degrees is 84% ​​or higher. [2] The dielectric multilayer film includes a high refractive index film with a refractive index of 2.0 or higher at a wavelength of 500 nm and a low refractive index film with a refractive index of 1.6 or lower at a wavelength of 500 nm, and the dielectric multilayer film has a QWOT of the high refractive index film at a wavelength of 500 nm. Ｈ QWOT of the low refractive index film at a wavelength of 500 nm is Q Ｌ When that happens, (a ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ ) ｎAn optical filter according to [1] having a repeating stacked structure represented by [a]. [n is a natural number greater than or equal to 9. a ｎ is 2.00 or higher, b ｎ is 0.40 or more and 0.90 or less, c ｎ is 0.20 or more and 0.50 or less, d ｎ is 0.40 or more and 0.90 or less. ] [3] The dielectric multilayer film is [(b ｎ The mean value + d ｎ (Average value of) / 2] - (c ｎ An optical filter according to [2], satisfying the average value of ≥ 0.24. [4] An optical filter according to [2] or [3], wherein n is 9 or more and 25 or less. [5] The dielectric multilayer film includes a high refractive index film with a refractive index of 2.0 or more at a wavelength of 500 nm and a low refractive index film with a refractive index of 1.6 or less at a wavelength of 500 nm, wherein the dielectric multilayer film has a QWOT of the high refractive index film at a wavelength of 500 nm. Ｈ QWOT of the low refractive index film at a wavelength of 500 nm is Q Ｌ When that happens, (a ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ ) ｎ The film has a repeating stacked structure represented by the (a ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ ) ｎ An optical filter described in any one of [2] to [4], which has only the repeating stacked structure represented by [2]. [n is a natural number greater than or equal to 9. a ｎ is 2.00 or higher, b ｎ is 0.40 or more and 0.90 or less, c ｎ is 0.20 or more and 0.50 or less, d ｎ is 0.40 or more and 0.90 or less. ] [6] The dielectric multilayer film is (e ｍ QＨ / f ｍ Q Ｌ / g ｍ Q Ｈ / h ｍ Q Ｌ ) ｍ An optical filter having a repeating stacked structure represented by [2] to [4], as described in any one of [2] to [4]. [m is a natural number of 1 or more. (a ｎ +e ｍ The average value of (b) is less than 2.40, ｎ +f ｍ The average value of (c) is between 0.40 and 0.90, and ｎ +g ｍ The average value of ) is 0.20 or more and 0.50 or less, (d ｎ +h ｍ The average value of the following is 0.40 or more and 0.90 or less. [7] The optical filter according to any one of [1] to [6], wherein the transparent substrate has near-infrared light absorption properties. [8] The optical filter according to any one of [1] to [7], wherein the transparent substrate is near-infrared light absorbing glass. [9] The optical filter according to any one of [1] to [8], comprising a light absorption layer containing a resin and a near-infrared light absorbing dye.

[10] The optical filter according to [9], wherein the near-infrared light absorbing dye contains a squarylium dye.

[11] A solid-state image sensor comprising the optical filter according to any one of [1] to

[10] .

[0063] The present invention will be described in more detail below using examples, but the present invention is not limited to these. A UV-Vis spectrophotometer (Hitachi High-Technologies Corporation, UH-4150 model) was used to measure each spectral characteristic. Unless otherwise specified, the spectral characteristics are measured at an incident angle of 0 degrees (perpendicular to the main surface of the optical filter).

[0064] <Glass Substrate> As a non-light-absorbing glass, glass A was D263 glass (Schott, borosilicate glass, commercially available, 0.3 mm thick). As a light-absorbing glass, glass B was phosphate glass containing copper (0.2 mm thick). Figure 3 shows the transmittance curve of glass B for light with wavelengths of 350 to 1200 nm.

[0065] <Near-infrared absorbing dyes> The dyes used in Example 3 are as follows: Compound 1 (merocyanine compound): Synthesized according to German Patent Publication No. 10109243. Compound 2 (squallium compound): Synthesized according to International Publication No. 2017 / 135359. Compound 3 (squallium compound): Synthesized according to U.S. Patent No. 5543086. Compounds 2 and 3 are near-infrared absorbing dyes (NIR dyes), and compound 1 is a near-ultraviolet absorbing dye (UV dye).

[0066]

[0067] <Example 1: Optical filter> On one main surface of a glass substrate, SiO ２ and TiO ２ By depositing these layers, a dielectric multilayer film 1 with the configuration shown in Table 2 was formed. Film No. 1 is on the substrate side. Based on the above, the optical filter of Example 1 was fabricated. SiO ２ : Refractive index 1.48 TiO at a wavelength of 500 nm ２ :Refractive index 2.56 at a wavelength of 500 nm. Note that among the configurations shown in Table 2, layers No. 1, 2, 47, and 48 are ripple suppression layers. Therefore, the dielectric multilayer film 1 has a repeating stacked structure (a ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ ) ｎ It consists only of repeating layered structures represented by .

[0068] <Example 2: Optical filter> On one main surface of the glass substrate, SiO ２ and TiO ２ and Al ２ O ３ By laminating these materials by vapor deposition, a dielectric multilayer film 2 with the configuration shown in Table 3 was formed. Film No. 1 is on the substrate side. Based on the above, the optical filter of Example 2 was fabricated. Al ２ O ３:Refractive index 1.63 at 500 nm. Note that among the configurations shown in Table 3, layers No. 1, 2, 48, and 49 are ripple suppression layers. Therefore, the dielectric multilayer film 2 has a repeating stacked structure (a ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ ) ｎ It consists only of repeating layered structures represented by .

[0069] <Example 3: Optical filter> On one main surface of the glass substrate, SiO ２ and TiO ２ A dielectric multilayer film 3-1 with the configuration shown in Table 4 was formed by depositing layers of material. Film No. 1 is on the substrate side. Near-infrared light absorbing dyes were dissolved in polyimide resin C-3G30G manufactured by Mitsubishi Gas Chemical Co., Ltd., and mixed at the concentrations shown in Table 1 below. A coating solution was obtained by stirring and dissolving at 50°C for 2 hours. The obtained coating solution was applied to the surface of the dielectric multilayer film 3-1 by spin coating to form a light absorbing layer with the thickness shown in Table 1 below.

[0070]

[0071] On the surface of the light-absorbing layer, SiO ２ and TiO ２ By depositing these layers, a dielectric multilayer film 3-2 with the configuration shown in Table 5 was formed. Film No. 1 is the light-absorbing layer. On the other main surface of the glass substrate, SiO ２ and TiO ２ By depositing these layers, a dielectric multilayer film 3-3 with the configuration shown in Table 6 was formed. Film No. 1 is on the substrate side. Based on the above, the optical filter of Example 3 was fabricated. Note that among the configurations shown in Table 6, films with layer numbers No. 1, 2, 47, and 48 are ripple suppression layers. Therefore, the dielectric multilayer film 3-2 has a repeating stacked structure (a ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ ) ｎIt consists only of repeating layered structures represented by .

[0072] <Example 4: Optical filter> On one main surface of the glass substrate, SiO ２ and TiO ２ A dielectric multilayer film 4 with the configuration shown in Table 7 was formed by laminating these layers by vapor deposition. In the dielectric multilayer film 4, layers No. 1, 2, 51, and 52 are ripple suppression layers. Layers No. 15-18, No. 19-22, No. 23-26, No. 27-30, No. 31-34, No. 35-38, No. 39-42, No. 43-46, and No. 47-50 are (a ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ ) ｎ This corresponds to a repeating layered structure represented by (e). Layers No. 3 to 6, No. 7 to 10, and No. 11 to 14 are each (e ｍ Q Ｈ / f ｍ Q Ｌ / g ｍ Q Ｈ / h ｍ Q Ｌ ) ｍ This corresponds to the repeating stacked structure represented by [the formula shown]. Based on the above, the optical filter of Example 4 was fabricated.

[0073] <Example 5: Optical filter> On one main surface of the glass substrate, SiO ２ and TiO ２ A dielectric multilayer film 5 with the configuration shown in Table 8 was formed by laminating these layers by vapor deposition. In the dielectric multilayer film 5, layers No. 1, 2, 59, and 60 are ripple suppression layers. Layers No. 7 to 10, No. 11 to 14, No. 15 to 18, No. 19 to 22, No. 23 to 26, No. 27 to 30, No. 31 to 34, No. 35 to 38, No. 39 to 42, No. 43 to 46, No. 47 to 50, No. 51 to 54, and No. 55 to 58 are (a ｎ Q Ｈ / bｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ ) ｎ This corresponds to a repeating layered structure represented by . The films with layer numbers 3 to 6 are (e ｍ Q Ｈ / f ｍ Q Ｌ / g ｍ Q Ｈ / h ｍ Q Ｌ ) ｍ This corresponds to the repeating stacked structure represented by [the formula shown]. Based on the above, the optical filter of Example 5 was fabricated.

[0074] <Example 6: Optical filter> On one main surface of the glass substrate, SiO ２ and TiO ２ By depositing these layers, a dielectric multilayer film 6 with the configuration shown in Table 9 was formed. Based on the above, the optical filter of Example 6 was fabricated.

[0075] <Example 7: Optical filter> On one main surface of the glass substrate, SiO ２ and TiO ２ A dielectric multilayer film 7 with the configuration shown in Table 10 was formed by laminating by vapor deposition. In the dielectric multilayer film 7, layer numbers 1, 2, 47, and 48 are ripple suppression layers. Layers 7 to 10, 11 to 14, 15 to 18, 19 to 22, 23 to 26, 27 to 30, 31 to 34, 35 to 38, 39 to 42, and 43 to 46 are (a ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ ) ｎ This corresponds to a repeating layered structure represented by . The films with layer numbers 3 to 6 are (e ｍ Q Ｈ / f ｍ Q Ｌ / g ｍ Q Ｈ / h ｍ QＬ ) ｍ This corresponds to the repeating stacked structure represented by [the formula shown]. Based on the above, the optical filter of Example 7 was fabricated.

[0076]

[0077]

[0078]

[0079]

[0080]

[0081]

[0082]

[0083]

[0084]

[0085] For each optical filter obtained as described above, spectral transmittance curves were measured using a UV-Vis spectrophotometer at incident angles of 0, 30, and 60 degrees in the wavelength range of 700 to 1000 nm, and spectral reflectance curves were measured at incident angles of 5 and 60 degrees in the wavelength range of 350 to 1000 nm. The reflectance was measured from the dielectric multilayer film side (dielectric multilayer film 3-3 side in Example 3). From the obtained spectral characteristic data, the characteristics shown in Table 11 below were calculated. The spectral transmittance and reflectance curves for each optical filter in Examples 1 to 7 are shown in Figures 4 to 14, respectively.

[0086] Examples 1-3 and 7 are examples, while Examples 4-6 are comparative examples.

[0087]

[0088] As shown in the above results and the spectral transmittance and reflectance curves of each filter, the optical filters of Examples 1-3 and Example 7 suppressed ripple in the visible light region even at high incidence angles, as shown in characteristics (ii-1) to (ii-4), and maintained near-infrared light reflection characteristics even at high incidence angles, as shown in characteristics (iii-1) to (iii-4), thus blocking near-infrared light. On the other hand, the filters of Examples 4-5 had particularly small near-infrared light reflection characteristics at high incidence angles, as shown in characteristics (iii-3) to (iii-4), and the filter of Example 6 did not suppress ripple in the visible light region, as shown in characteristics (ii-1) to (ii-4), and also had low near-infrared light reflection characteristics, as shown in characteristics (iii-2) and (iii-4). In Examples 4-5, the dielectric multilayer film is (a ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ ) has 9 or more repeating stacked structures, but the repeating stacked structure is (a ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ ) not only, but (e ｍ Q Ｈ / f ｍ Q Ｌ / g ｍ Q Ｈ / h ｍ Q Ｌ ) ｍ This also includes (a ｎ +e ｍ Since the average value of ) is not less than 2.40, it is thought that the above result occurred. Example 6 is a dielectric multilayer film (a ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ It is thought that the above result occurred because the dielectric multilayer film does not have a repeating stacked structure of (a ｎ QＨ / b ｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ ) has 9 or more repeating stacked structures, and the repeating stacked structure is (a ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ ) not only, but (e ｍ Q Ｈ / f ｍ Q Ｌ / g ｍ Q Ｈ / h ｍ Q Ｌ ) ｍ This also includes, and (b ｎ +f ｍ ) average value, (c ｎ +g ｍ ) average value, (d ｎ +h ｍ The average value of (a) is within a predetermined range, and ｎ +e ｍ The above results are likely due to the average value of ) being less than 2.40.

[0089] 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. 2024-230617, filed on 26 December 2024, the contents of which are incorporated herein by reference.

[0090] The optical filter according to this embodiment has excellent optical properties, suppressing ripple in the visible light region even at high incidence angles and maintaining near-infrared light reflection characteristics even at high incidence angles. 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.

[0091] 1A, 1B... Optical filters 10... Transparent substrate 20A, 20B, 20C... Dielectric multilayer film 30... Light absorption layer

Claims

1. An optical filter comprising a transparent substrate and a dielectric multilayer film provided on at least one main surface of the transparent substrate, wherein the optical filter satisfies all of the following characteristics (i-1) to (i-3) when outputting transmittance in units of 1 nm in the wavelength range of 350 to 1200 nm, and satisfies all of the following characteristics (ii-1) to (ii-4) and (iii-1) to (iii-4) when light is incident on the dielectric multilayer film side. (i-1) At wavelengths of 900 to 1000 nm, there are 20 or more particles with a transmittance of 0.15% or less at an incident angle of 0 degrees. (i-2) At wavelengths of 900 to 1000 nm, there are 23 or more particles with a transmittance of 0.3% or less at an incident angle of 30 degrees. (i-3) At wavelengths of 750 to 850 nm, there are 22 or more particles with a transmittance of 1% or less at an incident angle of 60 degrees. (ii-1) At wavelengths of 420 to 750 nm, the average reflectance at an incident angle of 5 degrees is 3% or less. (ii-2) At wavelengths of 420 to 750 nm, the maximum reflectance at an incident angle of 5 degrees is 10% or less. (ii-3) At wavelengths of 420 to 690 nm, the average reflectance at an incident angle of 60 degrees is 15% or less. (ii-4) At wavelengths of 420 to 690 nm, the maximum reflectance at an incident angle of 60 degrees is 40% or less. (iii-1) Average reflectance of 99.5% or higher at wavelengths of 900-1000 nm and an incident angle of 5 degrees. (iii-2) Minimum reflectance of 98% or higher at wavelengths of 900-1000 nm and an incident angle of 5 degrees. (iii-3) Average reflectance of 94% or higher at wavelengths of 750-850 nm and an incident angle of 60 degrees. (iii-4) Minimum reflectance of 84% or higher at wavelengths of 750-850 nm and an incident angle of 60 degrees.

2. The dielectric multilayer film includes a high refractive index film having a refractive index of 2.0 or more at a wavelength of 500 nm and a low refractive index film having a refractive index of 1.6 or less at a wavelength of 500 nm. The dielectric multilayer film has a QWOT at a wavelength of 500 nm of the high refractive index film as Q ｎ , and a QWOT at a wavelength of 500 nm of the low refractive index film as Q Ｌ . When it is set as (a ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ ), the optical filter according to claim 1 having a repeating laminated structure represented by ｎ . [n is a natural number of 9 or more. a ｎ is 2.00 or more, b ｎ is 0.40 or more and 0.90 or less, c ｎ is 0.20 or more and 0.50 or less, d ｎ is 0.40 or more and 0.90 or less.] 3. The dielectric multilayer film is [(b ｎ The mean value + d ｎ (Average value of) / 2] - (c ｎ The optical filter according to claim 2, satisfying the mean value of ≥ 0.

24.

4. The optical filter according to claim 2, wherein n is 9 or more and 25 or less.

5. The dielectric multilayer film includes a high refractive index film with a refractive index of 2.0 or higher at a wavelength of 500 nm and a low refractive index film with a refractive index of 1.6 or lower at a wavelength of 500 nm, wherein the dielectric multilayer film has a QWOT of the high refractive index film at a wavelength of 500 nm. Ｈ QWOT of the low refractive index film at a wavelength of 500 nm is Q Ｌ When that happens, (a ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ ) ｎ The film has a repeating stacked structure represented by the (a ｎ Q Ｈ / b ｎ Q Ｌ / c ｎ Q Ｈ / d ｎ Q Ｌ ) ｎ The optical filter according to claim 1, wherein the structure is a repeating stacked structure represented by [a]. [n is a natural number greater than or equal to 9. a] ｎ is 2.00 or higher, b ｎ is 0.40 or more and 0.90 or less, c ｎ is 0.20 or more and 0.50 or less, d ｎ [It is between 0.40 and 0.90] 6. The dielectric multilayer film is (e ｍ Q Ｈ / f ｍ Q Ｌ / g ｍ Q Ｈ / h ｍ Q Ｌ ) ｍ An optical filter according to claim 2, having a repeating stacked structure represented by (a). [m is a natural number of 1 or more. (a ｎ +e ｍ The average value of (b) is less than 2.40, ｎ +f ｍ The average value of (c) is between 0.40 and 0.90, and ｎ +g ｍ The average value of ) is between 0.20 and 0.50, (d ｎ +h ｍ The average value of ) is between 0.40 and 0.

90.

7. The optical filter according to claim 1, wherein the transparent substrate has near-infrared light absorption properties.

8. The optical filter according to claim 1, wherein the transparent substrate is a near-infrared light absorbing glass.

9. The optical filter according to claim 1, comprising a light-absorbing layer containing a resin and a near-infrared light-absorbing dye.

10. The optical filter according to claim 9, wherein the near-infrared light absorbing dye comprises a squarylium dye.

11. A solid-state image sensor comprising an optical filter according to any one of claims 1 to 10.

Images