JP2022077314A - Optical filter - Google Patents

Abstract

To provide an optical filter that has a high transmissivity for visible light and a high shielding property for near-infrared light, that suppresses a ripple even at a high incident angle, and that prevents the shielding property for near-infrared light from changing at a high incident angle.SOLUTION: An optical filter includes a substrate, and a dielectric multilayer film stacked as the outermost layer on at least one principal surface of the substrate. The substrate includes a resin film that contains a resin, and a color matter (IR) having the maximum absorption wavelength in a range from 680 to 1000 nm in dichloromethane. The optical filter satisfies all of specific optical characteristics (i-1) to (i-10) in spectral transmittance curves at respective incident angles of 0, 5, and 40 degrees.SELECTED DRAWING: Figure 1

Description

The present invention relates to an optical filter that transmits light in the visible wavelength region and blocks light in the near infrared wavelength region.

In order to reproduce the color tone well and obtain a clear image, the image pickup device using the solid-state image pickup element transmits light in the visible region (hereinafter, also referred to as "visible light") and transmits light in the ultraviolet wavelength region (hereinafter, "ultraviolet"). An optical filter that blocks light (also referred to as "light") or light in the near-infrared wavelength region (hereinafter also referred to as "near-infrared light") is used.

In such an optical filter, for example, dielectric thin films having different refractive indexes are alternately laminated on one side or both sides of a transparent substrate (dielectric multilayer film), and reflection that reflects the light to be shielded by utilizing the interference of light is used. Various methods such as type filters can be mentioned.

An optical filter having a dielectric multilayer film changes the optical film thickness of the dielectric multilayer film depending on the incident angle of light, so that the spectral transmission curve changes depending on the incident angle and high reflectance at a high incident angle. The problems are light loss, which increases the transmittance of the near-infrared light to be obtained, and the generation of noise due to the near-infrared light reflected by the dielectric multilayer film. When such a filter is used, the spectral sensitivity of the solid-state image sensor may be affected by the incident angle. In particular, it is expected to be used under high incident angle conditions due to the recent decrease in camera module height.

Further, in the dielectric multilayer film, a drastic change (ripple) in the transmittance may occur due to the interference caused by the reflected light at the interface of each layer depending on the number of layers of the multilayer film. Further, the larger the incident angle, the larger the ripple occurs. The dielectric multilayer film used for the optical filter that transmits light in the visible wavelength region and blocks light in the near-infrared wavelength region transmits visible light and blocks long-wavelength light after near-infrared light. Designed. Here, the conventional dielectric multilayer film is designed to suppress light leakage in the near-infrared light region, while ripple occurs in the visible light region, and the incident angle considered is up to about 30 degrees. ..

Patent Document 1 describes a near-infrared cut filter having a dielectric multilayer film and suppressing ripples in the visible light region at a high incident angle.
Patent Document 2 describes an optical filter in which the dependence on the incident angle is reduced without providing a dielectric multilayer film by combining various near-infrared absorbing dyes.

Japanese Unexamined Patent Publication No. 2019-120942 Japanese Unexamined Patent Publication No. 2019-32371

However, in the near-infrared cut filter described in Patent Document 1, the spectral transmittance curve changes at a high incident angle, and the shielding property in the near-infrared light region changes.
In the optical filter described in Patent Document 2, visible light is also absorbed by a dye used in a large amount to secure the shielding property and the incident angle dependence in the near infrared light region, and the transmittance in the visible light region is low. ..

The present invention has high transmission of visible light and high shielding property of near-infrared light, ripple is suppressed even at a high incident angle, and change in shielding property of near-infrared light at a high incident angle is suppressed. It is an object of the present invention to provide an optical filter.

The present invention provides an optical filter having the following configuration.
[1] An optical filter including a base material and a dielectric multilayer film laminated as an outermost layer on at least one main surface side of the base material.
The base material has a resin film containing a dye (IR) and a resin, and has a resin film.
The dye (IR) has a maximum absorption wavelength at 680-1000 nm in dichloromethane.
An optical filter in which the optical filter satisfies all of the following optical characteristics (i-1) to (i-10).
(I-1) At a wavelength of 450 to 500 nm, the average reflectance R _{450-500 (5 deg) AVE} at an incident angle of 5 degrees is 3% or less, and the average reflectance R _{450-500 (} 40 deg) at an incident angle of 40 degrees. _{) AVE} is 5% or less (i-2) Average reflectance at an incident angle of 5 degrees at a wavelength of 500 to 580 nm R _{500-580 (5 deg) AVE} is 2.5% or less and an average at an incident angle of 40 degrees. Reflectivity R _{500-580 (40 deg) AVE} is 4% or less (i-3) R _{450-500 (5 deg) AVE} > R _{500-580 (5 deg) AVE} and R _{450-500 (40 deg) AVE} > At a wavelength of (i-4) 450 to 580 nm that satisfies the relationship of R _{500-580 (40 deg) AVE} , the maximum reflectance R _{450-580 (5 deg) MAX} at an incident angle of 5 degrees is 4% or less and the incident angle. Maximum reflectance at 40 degrees R _{450-580 (40 deg) MAX} is 6% or less (i-5) Difference between the transmittance at an incident angle of 0 degrees and the transmittance at an incident angle of 40 degrees at a wavelength of 450 to 500 nm. The maximum value of is 6% or less (i-6), and the maximum value of the difference between the transmittance at an incident angle of 0 degrees and the transmittance at an incident angle of 40 degrees is 5% or less (i-7) at a wavelength of 500 to 580 nm. Average transmission T _{450-580 (0deg) AVE} at an incident angle of 0 degrees at a wavelength of 450 to 580 nm is 88% or more (i-8) Transmission is 20% at an incident angle of 0 degrees at a wavelength of 600 to 800 nm. When the absolute value of the difference between the wavelength and the wavelength at which the transmittance is 20% at an incident angle of 40 degrees is 10 nm or less (i-9) at a wavelength of 600 to 800 nm, the wavelength at which the transmittance is 20% at an incident angle of 0 degrees is At a (i-10) wavelength range of 640 to 690 nm and a wavelength of 750 to 1000 nm, the maximum transmission rate _{T750-1000 (0deg) MAX} at an incident angle of 0 degrees is 1% or less, and the maximum transmission is at an incident angle of 40 degrees. Rate _{T750-1000 (40deg) MAX} is 1% or less

According to the present invention, it has high transparency of visible light and high shielding property of near-infrared light, ripple is suppressed even at a high incident angle, and change in shielding property of near-infrared light at a high incident angle is suppressed. Optical filters can be provided.

FIG. 1 is a cross-sectional view schematically showing an example of an optical filter of one embodiment. FIG. 2 is a cross-sectional view schematically showing another example of the optical filter of one embodiment. FIG. 3 is a cross-sectional view schematically showing another example of the optical filter of one embodiment. FIG. 4 is a cross-sectional view schematically showing another example of the optical filter of one embodiment. FIG. 5 is a diagram showing a spectral transmittance curve of the dielectric multilayer film 1 of Example 2-1. FIG. 6 is a diagram showing a spectral transmittance curve of the dielectric multilayer film 2 of Example 2-2.

Hereinafter, embodiments of the present invention will be described.
In the present specification, the near-infrared absorbing dye may be abbreviated as "NIR dye" and the ultraviolet absorbing dye may be abbreviated as "UV dye".
In the present specification, the compound represented by the formula (I) is referred to as a compound (I). The same applies to compounds represented by other formulas. The dye composed of compound (I) is also referred to as dye (I), and the same applies to other dyes. Further, the group represented by the formula (I) is also referred to as a group (I), and the same applies to the groups represented by other formulas.

In the present specification, the internal transmittance is a transmittance obtained by subtracting the influence of interfacial reflection from the actually measured transmittance represented by the formula {measured transmittance / (100-reflectance)} × 100.
In the present specification, the transmittance of the base material, the transmittance of the resin film including the case where the dye is contained in the resin, and the transmittance measured by dissolving the dye in a solvent such as dichloromethane are referred to as "transmittance". In all cases, it is "internal transmittance". On the other hand, the transmittance of the optical filter having the dielectric multilayer film is the measured transmittance.

In the present specification, for a specific wavelength region, for example, a transmittance of 90% or more means that the transmittance does not fall below 90% in the entire wavelength region, that is, the minimum transmittance is 90% or more in the wavelength region. To say. Similarly, for a specific wavelength range, for example, a transmittance of 1% or less means that the transmittance does not exceed 1% in the entire wavelength region, that is, the maximum transmittance is 1% or less in the wavelength region. .. The same applies to the internal transmittance. The average transmittance and the average internal transmittance in a specific wavelength range are arithmetic means of the transmittance and the internal transmittance for each 1 nm in the wavelength range.
The optical characteristics can be measured using an ultraviolet-visible spectrophotometer.
In the present specification, "-" representing a numerical range includes an upper and lower limit.

<Optical filter>
The optical filter of one embodiment of the present invention (hereinafter, also referred to as “the present filter”) includes a base material and a dielectric multilayer film laminated as an outermost layer on at least one main surface side of the base material, which will be described later. An optical filter that satisfies specific optical characteristics.
Here, the substrate has a resin film containing a dye (IR) having a maximum absorption wavelength of 680 to 1000 nm in dichloromethane and a resin. The dye (IR) is a NIR dye. Since the base material contains a dye that absorbs near-infrared rays, the absorption characteristics of the base material cause deterioration of optical characteristics at high incident angles of the dielectric multilayer film, for example, light omission and noise in the near-infrared region. Can be covered. Each dye and resin will be described later.

A configuration example of this filter will be described with reference to the drawings. 1 to 4 are sectional views schematically showing an example of an optical filter of one embodiment.
The optical filter 1A shown in FIG. 1 is an example in which the dielectric multilayer film 30 is provided on one main surface side of the base material 10. In addition, "having a specific layer on the main surface side of the base material" is not limited to the case where the layer is provided in contact with the main surface of the base material, and another function is provided between the base material and the layer. Including cases where layers are provided.

The optical filter 1B shown in FIG. 2 is an example in which the dielectric multilayer film 30 is provided on both main surface sides of the base material 10.

The optical filter 1C shown in FIG. 3 is an example in which the base material 10 has a support 11 and a resin film 12 laminated on one main surface side of the support 11. The optical filter 1C further has a dielectric multilayer film 30 on the resin film 12 and on the main surface side of the support 11 on which the resin film 12 is not laminated.

The optical filter 1D shown in FIG. 4 is an example in which the base material 10 has a support 11 and a resin film 12 laminated on both main surface sides of the support 11. The optical filter 1D further has a dielectric multilayer film 30 on each resin film 12.

The optical filter of the present invention satisfies all of the following optical characteristics (i-1) to (i-10).
(I-1) At a wavelength of 450 to 500 nm, the average reflectance R _{450-500 (5 deg) AVE} at an incident angle of 5 degrees is 3% or less, and the average reflectance R _{450-500 (} 40 deg) at an incident angle of 40 degrees. _{) AVE} is 5% or less (i-2) Average reflectance at an incident angle of 5 degrees at a wavelength of 500 to 580 nm R _{500-580 (5 deg) AVE} is 2.5% or less and an average at an incident angle of 40 degrees. Reflectivity R _{500-580 (40 deg) AVE} is 4% or less (i-3) R _{450-500 (5 deg) AVE} > R _{500-580 (5 deg) AVE} and R _{450-500 (40 deg) AVE} > At a wavelength of (i-4) 450 to 580 nm that satisfies the relationship of R _{500-580 (40 deg) AVE} , the maximum reflectance R _{450-580 (5 deg) MAX} at an incident angle of 5 degrees is 4% or less and the incident angle. Maximum reflectance at 40 degrees R _{450-580 (40 deg) MAX} is 6% or less (i-5) Difference between the transmittance at an incident angle of 0 degrees and the transmittance at an incident angle of 40 degrees at a wavelength of 450 to 500 nm. The maximum value of is 6% or less (i-6), and the maximum value of the difference between the transmittance at an incident angle of 0 degrees and the transmittance at an incident angle of 40 degrees is 5% or less (i-7) at a wavelength of 500 to 580 nm. Average transmission T _{450-580 (0deg) AVE} at an incident angle of 0 degrees at a wavelength of 450 to 580 nm is 88% or more (i-8) Transmission is 20% at an incident angle of 0 degrees at a wavelength of 600 to 800 nm. When the absolute value of the difference between the wavelength and the wavelength at which the transmittance is 20% at an incident angle of 40 degrees is 10 nm or less (i-9) at a wavelength of 600 to 800 nm, the wavelength at which the transmittance is 20% at an incident angle of 0 degrees is At a (i-10) wavelength range of 640 to 690 nm and a wavelength of 750 to 1000 nm, the maximum transmission rate _{T750-1000 (0deg) MAX} at an incident angle of 0 degrees is 1% or less, and the maximum transmission is at an incident angle of 40 degrees. Rate _{T750-1000 (40deg) MAX} is 1% or less

This filter, which satisfies all of the optical characteristics (i-1) to (i-10), has excellent transparency of visible light and shielding of near-infrared light, and ripple generation and near-red at a high incident angle of 40 degrees. This is an optical filter in which changes in the shielding property of external light are suppressed.

By satisfying the optical characteristics (i-1), (i-2) and (i-4), it means that the reflectance in the visible light region is sufficiently low.
In the optical property (i-1), R _{450-500 (5 deg) AVE} is preferably 2.5% or less, and R _{450-500 (40 deg) AVE} is preferably 4.5% or less.
In the optical property (i-2), R _{500-580 (5 deg) AVE} is preferably 2% or less, and R _{500-580 (40 deg) AVE} is preferably 3.5% or less.
In terms of optical characteristics (i-4), R _{450-580 (5 deg) MAX} is preferably 3.5% or less, and R _{450-580 (40 deg) MAX} is preferably 5.5% or less.

By satisfying the optical characteristic (i-3), it means that the reflectance of the green band, which is particularly important for the visibility of the sensor of the image pickup apparatus, is low.

By satisfying the optical characteristics (i-7), the transmittance in the visible light region is high, and the optical characteristics (i-1), (i-2) and (i-4) to (i-6) are satisfied. This means that the ripple is suppressed even at a high incident angle.

The optical property (i-5) is preferably 5.5% or less, more preferably 5% or less.
The optical property (i-6) is preferably 4.5% or less, more preferably 4% or less.

T _{450-580 (0 deg) AVE} is preferably 89% or more, more preferably 90% or more.

By satisfying the optical characteristics (i-8), in the near-infrared light absorption band having a wavelength of 600 to 800 nm, there is little shift (that is, change in the shielding property of near-infrared light) even at a high incident angle, and the color reproducibility is excellent. Means.
The optical property (i-8) is preferably 8 nm or less, more preferably 6 nm or less.

By satisfying the optical characteristic (i-9), it means that the infrared band can be shielded and visible transmitted light can be efficiently taken in. The optical property (i-9) is preferably in the range of 645 to 685 nm, more preferably in the range of 650 to 680 nm.

By satisfying the optical characteristic (i-10), it means that the light-shielding property is excellent in the near-infrared light to long wavelength region having a wavelength of 750 to 1000 nm at both an incident angle of 0 degree and a high incident angle of 40 degrees. _{T750-1000 (0 deg) MAX} is preferably 0.95% or less, more preferably 0.9% or less. _{T750-1000 (40 deg) MAX} is preferably 0.95% or less, more preferably 0.9% or less.

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

In this filter, it is preferable that the dielectric multilayer film satisfies all of the following optical characteristics (iv-1) to (iv-8).
(Iv-1) At a wavelength of 450 to 580 nm, the average transmittance T _{450-580 (0 deg) AVE} at an incident angle of 0 degrees is 90% or more, and the average transmittance T _{450-580 (} 40 deg) at an incident angle of 40 degrees. _{) When the AVE} is 90% or more (iv-2) at a wavelength of 450 to 500 nm, the absolute value of the difference between the average transmittance at an incident angle of 0 degrees and the average transmittance at an incident angle of 40 degrees is 3% or less (iv-3). ) The absolute value of the difference between the average transmittance at an incident angle of 0 degrees and the average transmittance at an incident angle of 40 degrees is 2% or less at a wavelength of 500 to 580 nm (iv-4). The maximum value of the difference between the transmittance at 10 degrees and the transmittance at an incident angle of 40 degrees is 6% or less (iv-5). At a wavelength of 500 to 580 nm, the transmittance at an incident angle of 0 degrees and the transmittance at an incident angle of 40 degrees. When the maximum value of the difference from the transmittance is 5% or less (iv-6) at a wavelength of 600 to 800 nm, the wavelength at which the transmittance is 20% at an incident angle of 0 degrees is in the range of 720 to 770 nm (iv-7). Maximum transmittance at an incident angle of 0 degrees at a wavelength of 780 to 850 nm T _{780-850 (0 deg) MAX} is 4% or more and less than 10% (iv-8) Maximum transmittance at an incident angle of 40 degrees at a wavelength of 900 to 980 nm T _{900-980 (40 deg) MAX} is 1% or more and less than 5%

By satisfying the optical characteristic (iv-1), it means that the transparency in the visible light region is excellent at both the incident angle of 0 degree and the high incident angle of 40 degrees.
T _{450-580 (0 deg) AVE} is preferably 91% or more, more preferably 92% or more.
T _{450-580 (40 deg) AVE} is preferably 90.5% or more, more preferably 91% or more.

By satisfying the optical characteristics (iv-2) to (iv-5), it means that the generation of ripple in the visible light region is suppressed even at a high incident angle of 40 degrees.
The optical property (iv-2) is preferably 2.5% or less, more preferably 2% or less.
The optical property (iv-3) is preferably 1.6% or less, more preferably 1.2% or less.
The optical property (iv-4) is preferably 5.5% or less, more preferably 5% or less.
The optical property (iv-5) is preferably 4.5% or less, more preferably 4% or less.

By satisfying the optical characteristics (iv-6), it means that the transmittance in the red band is excellent and the light-shielding property is excellent in the near-infrared light region having a wavelength of 770 nm or later. The optical property (iv-6) is preferably in the range of 725 to 765 nm, more preferably in the range of 730 to 760 nm.

The optical characteristics (iv-7) to (iv-8) define an allowable range of light leakage in the near-infrared light region.
T _{780-850 (0 deg) MAX} is preferably 4-9%, more preferably 4-8%.
T _{900-980 (40 deg) MAX} is preferably 1 to 4.5%, more preferably 1 to 4%.

As shown in the optical characteristics (iv-2) to (iv-5), the dielectric multilayer film in the present invention suppresses the generation of ripples in the visible light region even at a high incident angle of 40 degrees.
On the other hand, as shown in the above optical characteristics (iv-7) to (iv-8), light leakage may occur in the near-infrared light wavelength region of incident angles of 0 degrees and 40 degrees and 780 nm or later. Since such a wavelength region is covered by the absorption of the NIR dye of the resin film described later, even if light leakage occurs, the optical filter as a whole is shielded from light.

By combining such a dielectric multilayer film and a resin film described later, the optical filter of the present invention has high visible light transmittance shown in the optical property (i-7) and the near field shown in the optical property (i-10). It has a high shielding property of infrared light, and as shown in the optical characteristics (i-1) to (i-2) and (i-4) to (i-6), ripple is suppressed even at a high incident angle. As shown in the optical characteristics (i-8), this is an optical filter in which the change in shielding property at a high incident angle of near-infrared light is suppressed.

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

The NIR reflective layer is a dielectric multilayer film designed to shield light in the near infrared region. The NIR reflective layer has, for example, wavelength selectivity that transmits visible light and mainly reflects light in the near infrared region other than the light shielding region of the resin film that is the absorption layer. The reflection region of the NIR reflection layer may include a light-shielding region in the near-infrared region of the resin film. The NIR reflection layer is not limited to the NIR reflection characteristic, and may be appropriately designed to have specifications for further blocking light in a wavelength range other than the near infrared region, for example, the near ultraviolet region.

The NIR reflective layer is composed of, for example, a dielectric multilayer film in which a low refractive index dielectric film (low refractive index film) and a high refractive index dielectric film (high refractive index film) are alternately laminated. The high refractive index film preferably has a refractive index of 1.6 or more, more preferably 2.2 to 2.5. Examples of the material of the high refractive index film include Ta ₂ O ₅ , TIO ₂ , and Nb ₂ O ₅ . Of these, TiO ₂ is preferable from the viewpoints of film formation property, reproducibility in refractive index and the like, stability and the like.

On the other hand, the low refractive index film preferably has a refractive index of less than 1.6, more preferably 1.45 or more and less than 1.55. Examples of the material of the low refractive index film include SiO ₂ , SiO _x N _y and the like. SiO ₂ is preferable from the viewpoint of reproducibility, stability, economy and the like in terms of film forming property.

In order to obtain a multilayer film in which light loss may occur in the near-infrared light wavelength region of 780 nm or later instead of suppressing ripple even at a high incident angle, for example, reducing the number of layers of the multilayer film can be mentioned.

The total number of dielectric multilayer films constituting the NIR reflective layer is preferably 20 or more, more preferably 25 or more, and further preferably 30 from the viewpoint of light-shielding property in the near-infrared wavelength region. That is all. However, when the total number of layers increases, ripples, warpage, etc. occur and the film thickness increases. Therefore, the total number of layers is preferably 100 layers or less, more preferably 75 layers or less, and even more preferably 60 layers or less. preferable.
The film thickness of the reflective layer is preferably 2 to 10 μm as a whole from the viewpoint of reducing the warp of the optical filter.

Further, for forming the dielectric multilayer film, for example, a vacuum film forming process such as a CVD method, a sputtering method or a vacuum vapor deposition method, a wet film forming process such as a spray method or a dip method can be used.

As the NIR reflective layer, one layer (a group of dielectric multilayer films) may give predetermined optical characteristics, or two layers may give predetermined optical characteristics. When having two or more layers, each reflective layer may have the same configuration or a different configuration. When having two or more reflective layers, it is usually composed of a plurality of reflective layers having different reflection bands. When two reflective layers are provided, one is a near-infrared reflective layer that shields light in the short wavelength band of the near infrared region, and the other is both the long wavelength band and the near ultraviolet region in the near infrared region. It may be used as a near-infrared / near-ultraviolet reflective layer that shields the light of.

Examples of the antireflection layer include a dielectric multilayer film, an intermediate refractive index medium, and a moth-eye structure in which the refractive index gradually changes. Of these, a dielectric multilayer film is preferable from the viewpoint of optical efficiency and productivity. The antireflection layer is obtained by alternately laminating dielectric multilayer films like the reflection layer.

<Base material>
In the optical filter of the present invention, the base material has a resin film containing a NIR dye (IR) and a resin described later.

<Optical characteristics of resin film>
It is preferable that the resin film satisfies all of the following optical characteristics (ii-1) to (ii-6).
(Ii-1) The average internal transmittance T _{450-580 AVE} at a wavelength of 450 to 580 nm is 88% or more. (Ii-2) At a wavelength of 600 to 700 nm, the wavelength at which the internal transmittance is 20% is in the range of 640 to 690 nm. (Ii-3) Internal transmittance T ₇₀₀ at a wavelength of 700 nm is 1% or less (ii-4) Internal transmittance T ₇₅₀ at a wavelength of 750 nm is 10% or less (ii-5) Internal transmittance T ₈₀₀ at a wavelength of 800 nm is 20%. Below (ii-6) Internal transmittance T ₉₅₀ at a wavelength of 950 nm is 60% or more and 95% or less.

By satisfying the optical characteristic (ii-1), it means that the transparency in the visible light region is high.
T _450-580AVE is preferably 89% or more, more preferably 90% or more.

By satisfying the optical characteristic (ii-2), it means that the oblique incident shift of the dielectric multilayer film having excellent transmittance in the red band and excellent light-shielding property in the near-infrared light region having a wavelength of 700 nm or later can be compensated.
The optical property (ii-2) is preferably in the range of 645 to 685 nm, more preferably 650 to 680 nm.

By satisfying the optical characteristics (ii-3) to (ii-5), it means that the wavelength range in which light leakage is likely to occur in the dielectric multilayer film can be shielded by absorption.
T ₇₀₀ is preferably 0.9% or less.
T ₇₅₀ is preferably 9.5% or less, more preferably 9% or less.
T ₈₀₀ is preferably 18% or less, more preferably 16% or less.

The optical property (ii-6) defines the range of transmittance allowed in the long wavelength region.
T ₉₅₀ is preferably 60% or more and 92.5% or less, and more preferably 60% or more and 90% or less.

<NIR dye>
NIR dye (IR) is a NIR dye having a maximum absorption wavelength of 680 to 1000 nm in dichloromethane. By containing such a dye, near-infrared light can be effectively cut.

The dye (IR) is described below in a spectral internal transmittance curve measured by dissolving the dye (IR) in the resin so that the internal transmittance at the maximum absorption wavelength is 10% in the resin constituting the resin film. It is preferable to satisfy the characteristic (iii-1).
(Iii-1) When the maximum absorption wavelength in the resin is D [nm] and the average internal transmittance at 450 to 580 nm is E, E> 100- (D / 100).

The dye (IR) has a maximum absorption wavelength in the near-infrared light region, but the larger the maximum absorption wavelength, the easier it is to absorb visible light, so that the transmittance in the visible light region tends to decrease. The characteristic (iii-1) defines the relationship between the maximum absorption wavelength and the lower limit of the visible light transmittance. Therefore, if the dye (IR) satisfies the characteristic (iii-1), it means that the visible light transmittance is sufficiently high.
The characteristic (iii-1) is more preferably E> 101.5- (D / 100).

The NIR dye (IR) may consist of one kind of compound or may contain two or more kinds of compounds. 3 has a maximum absorption wavelength of 680 to 1000 nm in dichloromethane from the viewpoint of easily satisfying the optical characteristics (ii-3) to (ii-6) of the resin film, which absorbs light in a wavelength range of 700 to 1000 nm widely. It is preferable to contain compounds of one or more species, and it is more preferable to contain one or more compounds selected from the compounds (A) to (C) having the following characteristics.
Compound (A): Compound having a maximum absorption wavelength in dichloromethane of 690 nm or more and less than 735 nm Compound (B): Compound having a maximum absorption wavelength of 735 nm or more and less than 835 nm in dichloromethane Compound (C): Wavelength of 900 nm in dichloromethane A compound having a maximum absorption wavelength of 1000 nm or more and 1000 nm or less

Further, the maximum value of the difference between the maximum absorption wavelength of the compound (A) and the maximum absorption wavelength of the compound (B) is preferably 40 nm or more, more preferably 50 nm or more. As a result, the wavelength range in which light leakage of the dielectric multilayer film is likely to occur can be efficiently blocked by absorption.

Compound (A) is selected from either a squarylium compound or a cyanine compound in an amount of one or more, compound (B) is selected from either a squarylium compound or a cyanine compound in an amount of one or more, and compound (C) is selected from a squarylium compound or a cyanine compound. It is preferable to select one or more of the cyanine compound and the immonium compound from the viewpoints of transparency in the visible light region, solubility in the resin, and durability.

<Squarylium compound>
The squarylium compound is preferably a compound represented by the following formula (I), a compound represented by the formula (II) described later, or a compound represented by the formula (V) described later.
When two or more identical symbols are present in the squarylium compound, the symbols may be the same or different. The same applies to the cyanine compound.

<Squarylium compound (I)>

However, the symbols in the above formula are as follows.
R ²⁴ and R ²⁶ are independently hydrogen atom, halogen atom, hydroxyl group, alkyl group or alkoxy group having 1 to 20 carbon atoms, acyloxy group having 1 to 10 carbon atoms, aryl group having 6 to 11 carbon atoms, respectively. An alaryl group having 7 to 18 carbon atoms, which may have a substituent and may have an oxygen atom between carbon atoms, -NR ²⁷ R ²⁸ (R ²⁷ and R ²⁸ are independent hydrogens, respectively. An atom, an alkyl group having 1 to 20 carbon atoms, -C (= O) -R ²⁹ (R ²⁹ may have a hydrogen atom, a halogen atom, a hydroxyl group, or a substituent, and an unsaturated bond between carbon atoms. , Oxygen atom, a hydrocarbon group having 1 to 25 carbon atoms which may contain a saturated or unsaturated ring structure), -NHR ³⁰ , or _-SO2 -R ³⁰ (R ³⁰ is each one or more hydrogen atoms. May be substituted with a halogen atom, a hydroxyl group, a carboxy group, a sulfo group, or a cyano group, and may contain an unsaturated bond, an oxygen atom, a saturated or unsaturated ring structure between carbon atoms, and may have 1 to 25 carbon atoms. The group (R ⁴¹ , R ⁴² ) represented by the following formula (S) is independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms or an alkoxy. Indicates a group; k is 2 or 3).

R ²¹ and R ²² , R ²² and R ²⁵ , and R ²¹ and R ²³ are linked to each other to form a heterocycle A, a heterocycle B, and a heterocycle C having 5 or 6 members, respectively, together with a nitrogen atom. May be good.
When the heterocycle A is formed, R ²¹ and R ²² have a divalent group −Q— to which the hydrogen atom is bonded, such as an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an aryl group having 6 to 10 carbon atoms. An alkylene group or an alkyleneoxy group which may be substituted with an acyloxy group having 1 to 10 carbon atoms which may have a substituent is shown.
R ²² and R ²⁵ when the heterocycle B is formed, and R ²¹ and R ²³ when the heterocycle C is formed are divalent groups to which they are bonded-X1 ^- Y1 ^- and-, respectively. As X ² -Y ^2- (the side that binds to nitrogen is X ¹ and X ² ), X ¹ and X ² are the groups represented by the following formulas (1x) or (2x), respectively, and Y ¹ and Y ² are the groups, respectively. It is a group represented by any of the following formulas (1y) to (5y). When X ¹ and X ² are groups represented by the following formulas (2x), Y ¹ and Y ² may be single bonds, respectively, and in that case, oxygen atoms may be provided between carbon atoms. ..

In the formula (1x), the four Zs are independently hydrogen atoms, hydroxyl groups, alkyl or alkoxy groups having 1 to 6 carbon atoms, or -NR ³⁸ R ³⁹ (R ³⁸ and R ³⁹ are independent, respectively. Indicates a hydrogen atom or an alkyl group having 1 to 20 carbon atoms). R ³¹ to R ³⁶ are independent hydrogen atoms, alkyl groups having 1 to 6 carbon atoms or aryl groups having 6 to 10 carbon atoms, and R ³⁷ is an alkyl group having 1 to 6 carbon atoms or 6 to 10 carbon atoms. Indicates an aryl group.
R ²⁷ , R ²⁸ , R ²⁹ , R ³¹ to R ³⁷ , R ²¹ to R ²³ when no heterocycle is formed, and R ²⁵ are 5-membered rings coupled to any other of these. Alternatively, a 6-membered ring may be formed. R ³¹ and R ³⁶ and R ³¹ and R ³⁷ may be directly coupled.
When the heterocycle is not formed, R ²¹ , R ²² , R ²³ and R ²⁵ are independently hydrogen atom, halogen atom, hydroxyl group, alkyl group or alkoxy group having 1 to 20 carbon atoms, and carbon number. Shows an acyloxy group of 1 to 10, an aryl group having 6 to 11 carbon atoms, or an alaryl group having 7 to 18 carbon atoms which may have a substituent and may have an oxygen atom between carbon atoms. ..

Examples of the compound (I) include compounds represented by any of the formulas (I-1) to (I-3), which are soluble in a resin, heat resistance and light resistance in a resin, and the like. From the viewpoint of the visible light transmittance of the contained resin layer, the compound represented by the formula (I-1) is particularly preferable.

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

In compound (I-1), X ¹ is preferably a group (2x), and Y ¹ is preferably a single bond or a group (1y). In this case, as R ³¹ to R ³⁶ , a hydrogen atom or an alkyl group having 1 to 3 carbon atoms is preferable, and a hydrogen atom or a methyl group is more preferable. Specific examples of −Y ¹ − X ¹ − include divalent organic groups represented by the formulas (11-1) to (12-3).

-C (CH ₃ ) ₂ -CH (CH ₃ ) -... (11-1)
-C (CH ₃ ) ₂ -CH _2- ... (11-2)
-C (CH ₃ ) ₂ -CH (C ₂ H ₅ ) -... (11-3)
-C (CH ₃ ) ₂ -C (CH ₃ ) (nC ₃ H ₇ )-... (11-4)
-C (CH ₃ ) ₂ -CH ₂ -CH _2- ... (12-1)
-C (CH ₃ ) ₂ -CH ₂ -CH (CH ₃ ) -... (12-2)
-C (CH ₃ ) ₂ -CH (CH ₃ ) -CH _2- ... (12-3)

Further, in compound (I-1), R ²¹ is independently formulated (1) from the viewpoint of solubility, heat resistance, and steepness of change near the boundary between the visible region and the near infrared region in the spectral transmittance curve. The group represented by 4-1) or (4-2) is more preferable.

In formulas (4-1) and (4-2), R ⁷¹ to R ⁷⁵ independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms.

In compound (I-1), R ²⁴ is preferably -NR ²⁷ R ²⁸ . As the -NR ²⁷ R ²⁸ , -NH-C (= O) -R ²⁹ or -NH-SO ₂ -R ³⁰ is preferable from the viewpoint of solubility in the resin and the coating solvent.

In compound (I-1), a compound in which R ²⁴ is -NH-C (= O) -R ²⁹ is represented by the formula (I-11).

Independently, R ²³ and R ²⁶ are preferably a hydrogen atom, a halogen atom, or an alkyl group or an alkoxy group having 1 to 6 carbon atoms, and a hydrogen atom is more preferable.

The R ²⁹ may have an alkyl group having 1 to 20 carbon atoms which may have a substituent, an aryl group having 6 to 10 carbon atoms which may have a substituent, or a substituent. Preferably, an alaryl group having 7 to 18 carbon atoms, which may have an oxygen atom between carbon atoms, is preferable. Substituents include a hydroxyl group, a carboxy group, a sulfo group, a cyano group, an alkyl group having 1 to 6 carbon atoms, a fluoroalkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and an alkoxy group having 1 to 6 carbon atoms. Examples thereof include an acyloxy group.

The R ²⁹ has a linear, branched, cyclic alkyl group having 1 to 17 carbon atoms, a phenyl group which may be substituted with an alkoxy group having 1 to 6 carbon atoms, and an oxygen atom between carbon atoms. A group selected from an alaryl group having 7 to 18 carbon atoms which may be used is preferable.

As R ²⁹ , one or more hydrogen atoms may be independently substituted with a hydroxyl group, a carboxy group, a sulfo group, or a cyano group, and an unsaturated bond, an oxygen atom, a saturated or unsaturated bond between carbon atoms. A group which is a hydrocarbon group having 5 to 25 carbon atoms and having at least one branch, which may contain a ring structure, can also be preferably used.

Specific examples of the compound (I-11) include the compounds shown in the following table. In addition, the compounds shown in the table below have the same meaning on the left and right sides of the squarylium skeleton.

Among these, the compounds (I-11) include compounds (I-11-11) to (I-11-15) and (I-11) in terms of transparency in the visible light region and solubility in a resin. -26) to (I-11-30) and the like are preferable.

In compound (I-1), the compound in which R ²⁴ is -NH-SO ₂ -R ³⁰ is represented by the formula (I-12).

Independently, R ²³ and R ²⁶ are preferably a hydrogen atom, a halogen atom, or an alkyl group or an alkoxy group having 1 to 6 carbon atoms, and a hydrogen atom is more preferable.

From the viewpoint of light resistance, R ³⁰ is independently composed of an alkyl group or an alkoxy group having 1 to 12 carbon atoms which may have a branch, or a hydrocarbon group having 6 to 16 carbon atoms having an unsaturated ring structure. preferable. Examples of the unsaturated ring structure include benzene, toluene, xylene, furan, and benzofuran. R ³⁰ is more preferably an alkyl group or an alkoxy group having 1 to 12 carbon atoms which may independently have a branch. In each group showing R ³⁰ , a part or all of a hydrogen atom may be substituted with a halogen atom, particularly a fluorine atom.

Specific examples of the compound (I-12) include the compounds shown in the following table. In addition, the compounds shown in the table below have the same meaning on the left and right sides of the squarylium skeleton.

Among these, the compounds (I-12) include the compounds (I-12-11) to (I-12-15) and (I-12) in terms of transparency in the visible light region and solubility in the resin. -26) to (I-12-30) and the like are preferable.

<Squarylium compound (II)>

However, the symbols in the above formula are as follows.
Ring Z is a 5-membered ring or a 6-membered ring each independently having 0 to 3 heteroatoms in the ring, and the hydrogen atom contained in the ring Z may be substituted.
The carbon atoms or heteroatoms constituting ^R1 and ^R2 , ^R2 and R3 ^, and ^R1 and ring Z are linked to each other to form a heterocycle A1, a heterocycle B1 and a heterocycle C1 together with a nitrogen atom, respectively. In that case, the hydrogen atom contained in the heterocycle A1, the heterocycle B1 and the heterocycle C1 may be substituted. In the absence of forming a hetero ring, R ¹ and R ² each independently contain an unsaturated bond, a hetero atom, a saturated or unsaturated ring structure between a hydrogen atom, a halogen atom, or a carbon atom. Well, the hydrocarbon group which may have a substituent is shown. R ⁴ and R ³ in the case of not forming a hetero ring may independently contain a hetero atom between a hydrogen atom, a halogen atom, or a carbon atom, and may have a substituent or an alkyl group or a substituent. Indicates an alkoxy group.

Examples of the compound (II) include compounds represented by any of the formulas (II-1) to (II-3), from the viewpoint of solubility in the resin and visible light transmission in the resin. The compound represented by the formula (II-3) is particularly preferable.

In formulas (II-1) and (II-2), R ¹ and R ² each independently have a hydrogen atom, a halogen atom, or an alkyl group having 1 to 15 carbon atoms which may have a substituent. As shown, R ³ to R ⁶ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms which may have a substituent.

In formula (II-3), R ¹ , R ⁴ , and R ⁹ to R ¹² each independently contain a hydrogen atom, a halogen atom, or an alkyl group having 1 to 15 carbon atoms which may have a substituent. Shown, R ⁷ and R ⁸ each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms which may have a substituent.

R ¹ and R ² in compound (II-1) and compound (II-2) are preferably alkyl groups having 1 to 15 carbon atoms independently from the viewpoint of solubility in a resin, visible light transmission, and the like. , Alkyl groups having 7 to 15 carbon atoms are more preferable, and alkyl groups having at least one of R ¹ and R ² having a branched chain having 7 to 15 carbon atoms are more preferable, and both R ¹ and R ² have 8 carbon atoms. Alkyl groups having up to 15 branched chains are particularly preferred.

R ¹ in compound (II-3) is preferably an alkyl group having 1 to 15 carbon atoms and an alkyl group having 1 to 10 carbon atoms independently from the viewpoint of solubility in a transparent resin, visible light transmittance and the like. Is more preferable, and an ethyl group and an isopropyl group are particularly preferable.

From the viewpoint of visible light transmission and ease of synthesis, ^R4 is preferably a hydrogen atom or a halogen atom, and particularly preferably a hydrogen atom.
R ⁷ and R ⁸ are preferably an alkyl group having 1 to 5 carbon atoms which may be independently substituted with a hydrogen atom, a halogen atom or a halogen atom, and more preferably a hydrogen atom, a halogen atom or a methyl group.

R ⁹ to R ¹² are preferably alkyl groups having 1 to 5 carbon atoms, which may be independently substituted with a hydrogen atom, a halogen atom, or a halogen atom.
Examples of -CR ⁹ R ¹⁰ -CR ¹¹ R ^12- include divalent organic groups represented by the following groups (13-1) to (13-5).
-CH (CH ₃ ) -C (CH ₃ ) ₂ -... (13-1)
-C (CH ₃ ) ₂ -CH (CH ₃ ) -... (13-2)
-C (CH ₃ ) ₂ -CH _2- ... (13-3)
-C (CH ₃ ) ₂ -CH (C ₂ H ₅ ) -... (13-4)
-CH (CH ₃ ) -C (CH ₃ ) (CH ₂ -CH (CH ₃ ) ₂ )-... (13-5)

Specific examples of the compound (II-3) include the compounds shown in the following table. In addition, the compounds shown in the table below have the same meaning on the left and right sides of the squarylium skeleton.

The compounds (I) to (II) can be produced by known methods. Compound (I) can be produced by the method described in US Pat. No. 5,543,086, US Patent Application Publication No. 2014/0061505, and International Publication No. 2014/088063. Compound (II) can be produced by the method described in International Publication No. 2017/135359.

<Cyanine compound>
The cyanine compound is preferably a compound represented by the following formula (III) or formula (IV).

<Cyanine compounds (III), (IV)>

However, the symbols in the above formula are as follows.
R ¹⁰¹ to R ¹⁰⁹ and R ¹²¹ to R ¹³¹ each independently have a hydrogen atom, a halogen atom, an alkyl group having 1 to 15 carbon atoms which may have a substituent, or an aryl group having 5 to 20 carbon atoms. show. R ¹¹⁰ to R ¹¹⁴ and R ¹³² to R ¹³⁶ independently represent a hydrogen atom, a halogen atom, and an alkyl group having 1 to 15 carbon atoms, respectively.
X ^- represents a monovalent anion.
n1 and n2 are 0 or 1. The hydrogen atom bonded to the carbon ring containing-(CH ₂ ) _n1- and the carbon ring containing- (CH ₂ ) _n2- is a halogen atom and an alkyl group having 1 to 15 carbon atoms which may have a substituent. Alternatively, it may be substituted with an aryl group having 5 to 20 carbon atoms.

In the above, the alkyl group (including the alkyl group of the alkoxy group) may be linear, or may contain a branched structure or a saturated ring structure. The aryl group refers to a group bonded via a carbon atom constituting an aromatic ring of an aromatic compound, for example, a benzene ring, a naphthalene ring, a biphenyl, a furan ring, a thiophene ring, a pyrrole ring, or the like. Examples of the substituent in the alkyl group or alkoxy group having 1 to 15 carbon atoms or the aryl group having 5 to 20 carbon atoms which may have a substituent include a halogen atom and an alkoxy group having 1 to 10 carbon atoms. ..

In formulas (III) and (IV), R ¹⁰¹ and R ¹²¹ are preferably an alkyl group having 1 to 15 carbon atoms or an aryl group having 5 to 20 carbon atoms, and maintain a high visible light transmission rate in the resin. From the viewpoint, an alkyl group having 1 to 15 carbon atoms having a branch is more preferable.

In formulas (III) and (IV), R ¹⁰² to R ¹⁰⁵ , R ¹⁰⁸ , R ¹⁰⁹ , R ¹²² to R ¹²⁷ , R ¹³⁰ and R ¹³¹ are independently hydrogen atoms and alkyl groups having 1 to 15 carbon atoms, respectively. An alkoxy group or an aryl group having 5 to 20 carbon atoms is preferable, and a hydrogen atom is more preferable from the viewpoint of obtaining a high visible light transmittance.

In formulas (III) and (IV), R ¹¹⁰ to R ¹¹⁴ and R ¹³² to R ¹³⁶ are preferably hydrogen atoms independently or alkyl groups having 1 to 15 carbon atoms, respectively, from the viewpoint of obtaining high visible light transmittance. From hydrogen atom is more preferable.

R ¹⁰⁶ , R ¹⁰⁷ , R ¹²⁸ and R ¹²⁹ each independently contain a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms (chain, cyclic, branched alkyl group). It may be), and a hydrogen atom or an alkyl group having 1 to 15 carbon atoms is more preferable. Further, R ¹⁰⁶ and R ¹⁰⁷ , and R ¹²⁸ and R ¹²⁹ preferably have the same group.

Examples of X- include I- ^, BF _4- ^, PF _6- ^, ClO _4- ^, anions represented ^by the formulas (X1), and (X2), ^and the like, preferably BF _4- ^or PF _6- . be.

In the following description, the portion of compound (III) excluding R ¹⁰¹ to R ¹¹⁴ is also referred to as skeleton (III). The same applies to compound (IV).

In the formula (III), the compound having n1 is represented by the following formula (III-1), and the compound having n1 being 0 is represented by the following formula (III-2).

In formula (III-1) and formula (III-2), R ¹⁰¹ to R ¹¹⁴ and X ^- are the same as in the case of formula (III). R ¹¹⁵ to R ¹²⁰ represent an alkyl group or an alkoxy group having 1 to 15 carbon atoms which may independently have a hydrogen atom, a halogen atom and a substituent, or an aryl group having 5 to 20 carbon atoms. Each of R ¹¹⁵ to R ¹²⁰ is preferably a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms (may include a chain-like, cyclic, or branched alkyl group). A hydrogen atom or an alkyl group having 1 to 15 carbon atoms is more preferable. Further, it is preferable that R ¹¹⁵ to R ¹²⁰ have the same group.

In the formula (IV), the compound having n2 of 1 is represented by the following formula (IV-1), and the compound having n2 of 0 is represented by the following formula (IV-2).

In formula (IV-1) and formula (IV-2), R ¹²¹ to R ¹³⁶ and X ^- are the same as in the case of formula (IV). R ¹³⁷ to R ¹⁴² represent an alkyl group or an alkoxy group having 1 to 15 carbon atoms or an aryl group having 5 to 20 carbon atoms, which may independently have a hydrogen atom, a halogen atom and a substituent, respectively. R ¹³⁷ to R ¹⁴² are each independently a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms (may include a chain, cyclic, or branched alkyl group), and hydrogen is preferable. Atoms or alkyl groups having 1 to 15 carbon atoms are more preferable. Further, it is preferable that R ¹³⁷ to R ¹⁴² have the same group.

The compounds represented by the formulas (III-1), the formula (III-2), the formula (IV-1), and the formula (IV-2) are more specifically, the atoms bonded to each skeleton or the compounds. Examples include compounds in which the group is an atom or group shown in the table below. In all the compounds shown in the table below, R ¹⁰¹ to R ¹⁰⁹ are all the same on the left and right sides of the formula. In all the compounds shown in the table below, R ¹²¹ to R ¹³¹ are the same on the left and right of the formula.

R ¹¹⁰ -R ¹¹⁴ in the table below and R ¹³² -R ¹³⁶ in the table below indicate an atom or group bonded to the benzene ring in the center of each formula, and are described as "H" when all five are hydrogen atoms. When any of R ¹¹⁰ to R ¹¹⁴ is a substituent and the other is a hydrogen atom, only the combination of the code and the substituent which are the substituents is described. For example, the description of "R ¹¹² -C (CH ₃ ) ₃ " indicates that R ¹¹² is -C (CH ₃ ) ₃ and the others are hydrogen atoms. The same applies to R ¹³² -R ¹³⁶ .

R ¹¹⁵ -R ¹²⁰ in Table 4 and R ¹³⁷ -R ¹⁴² in Table 6 represent atoms or groups attached to the central cyclohexane ring in formula (III-1), formula (IV-1), all six of which represent. In the case of hydrogen atom, it is described as "H". When any of R ¹¹⁵ to R ¹²⁰ is a substituent and the other is a hydrogen atom, only the combination of the code and the substituent which are the substituents is described. The same applies to R ¹³⁷ -R ¹⁴² .

R ¹¹⁵ -R ¹¹⁸ in Table 5 and R ¹³⁷ -R ¹⁴⁰ in Table 7 indicate atoms or groups attached to the central cyclopentane ring in formulas (III-2) and (IV-2), all four. When is a hydrogen atom, it is described as "H". When any of R ¹¹⁵ to R ¹¹⁸ is a substituent and the other is a hydrogen atom, only the combination of the code and the substituent which are the substituents is described. The same applies to R ¹³⁷ -R ¹⁴⁰ .

Although X ^{-is not shown in the table below, X- is BF} _4- ^or PF _6- in any compound.

Among these, as the compound (III-1), the compounds (III-1-1) to (III-1-5) are preferable from the viewpoint of transparency in the visible light region and solubility in the resin.

Among these, as the compound (III-2), the compounds (III-2-1) to (III-2-5) are preferable from the viewpoint of transparency in the visible light region and solubility in the resin.

Among these, the compound (IV-1) is preferably compounds (IV-1-1) to (IV-1-5) from the viewpoint of transparency in the visible light region and solubility in a resin.

Among these, the compound (IV-2) is preferably compounds (IV-2-1) to (IV-2-5) from the viewpoint of transparency in the visible light region and solubility in a resin.

The skeletons of the compound (III) and the compound (IV) are different as described above, and thus the wavelength region of the absorption maximum is different. In compound (III), the maximum absorption wavelength is in the wavelength region of approximately 760 to 830 nm, although it depends on the type and combination of atoms and groups bonded to the skeleton. In compound (IV), the maximum absorption wavelength is in the wavelength range of approximately 800 to 900 nm, although it depends on the type and combination of atoms and groups bonded to the skeleton.

Further, in compound (III), the maximum absorption wavelength differs depending on whether n1 of the skeleton is 1 or 0. Although it depends on the type and combination of atoms and groups bonded to the skeleton, when n1 is 1, the maximum absorption wavelength is in the wavelength region of approximately 760 to 800 nm, and when n1 is 0, the maximum absorption wavelength is approximately 800 to 830 nm. It is in the wavelength range of.

Similarly, in compound (IV), the maximum absorption wavelength differs depending on whether n2 is 1 or n2 is 0. Although it depends on the type and combination of atoms and groups bonded to the skeleton (IV-1), when n2 is 1, the maximum absorption wavelength is in the wavelength region of approximately 800 to 830 nm, and when n2 is 0, the maximum absorption wavelength is. Is in the wavelength range of approximately 830 to 900 nm.

Compounds (III) and (IV) may be described, for example, in Days and pigments 73 (2007) 344-352 and J. Mol. It can be produced by the method described in Heterocyclic chem, 42,959 (2005).

<Squarylium compound (V)>

In the formula (V), R ⁵¹ to R ⁵⁴ are independently hydrogen atom, halogen atom, hydroxyl group, alkyl group, aryl group or alaryl group.
The alkyl group, aryl group or alaryl group may have a substituent.
Further, the alkyl group, aryl group or alaryl group may contain an unsaturated bond, an oxygen atom, an ester bond, an amide bond, or a thioamide bond between carbon atoms.
Further, the alkyl group, aryl group or alaryl group may have an oxygen atom, an ester bond, an amide bond, or a thioamide bond at the terminal bonded to the thiophene ring.
R ⁵¹ and R ⁵² , R ⁵² and R ⁵³ , and R ⁵³ and R ⁵⁴ may be linked to each other to form a monocyclic ring or a polycyclic ring in which 2 to 4 rings are condensed, in which case. The hydrogen atom bonded to the ring may be substituted with a substituent.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom and a chlorine atom are preferable.

When R ⁵¹ to R ⁵⁴ are alkyl groups, the number of carbon atoms is preferably 1 to 20, more preferably 1 to 15, and even more preferably 1 to 12.
When R ⁵¹ to R ⁵⁴ are aryl groups, the number of carbon atoms is preferably 4 to 20, more preferably 4 to 17, and even more preferably 4 to 14.
When R ⁵¹ to R ⁵⁴ are alaryl groups, the number of carbon atoms is preferably 5 to 20, more preferably 5 to 18, and even more preferably 5 to 15.
When R ⁵¹ to R ⁵⁴ have a substituent, the number of carbon atoms includes the number of carbon atoms of the substituent.

The substituents in R ⁵¹ to R ⁵⁴ include halogen atom, hydroxyl group, carboxy group, sulfo group, cyano group, amino group, N-substituted amino group, nitro group, alkoxycarbonyl group, carbamoyl group and N-substituted carbamoyl group. Examples thereof include an imide group and an alkoxy group having 1 to 10 carbon atoms. When R ⁵¹ to R ⁵⁴ are an aryl group or an alaryl group, the substituent is a group that substitutes a hydrogen atom bonded to an aromatic ring or a hydrogen atom of an alkyl group contained therein, and is further an aryl group in addition to the above-mentioned substituent. including.

R ⁵¹ and R ⁵² , R ⁵² and R ⁵³ , and R ⁵³ and R ⁵⁴ may be linked to each other to form a monocyclic ring or a polycyclic ring in which 2 to 4 rings are condensed, in which case. The hydrogen atom bonded to the ring may be substituted with a substituent.

When R ⁵² and R ⁵³ are linked, the squarylium compound (V) comprises a structure in which a ring is formed between two thiophene rings and at least three rings are fused. The hydrogen atom bonded to the ring formed by linking R ⁵² and R ⁵³ may be substituted with a substituent.
Examples of the substituent that replaces the hydrogen atom bonded to the ring in which R ⁵² and R ⁵³ are linked include a group similar to the substituent in R ⁵¹ to R ⁵⁴ and a phenyl group that may have a substituent. .. Examples of the substituent having the phenyl group include the same groups as the substituents in R ⁵¹ to R ⁵⁴ .

Each of R ⁵⁵ and R ⁵⁶ is an alkyl group or an alaryl group which may independently have a substituent and may contain an unsaturated bond between carbon atoms, an oxygen atom or a nitrogen atom. Alternatively, R ⁵⁵ and R ⁵⁶ may be linked to each other to form a cycloheterocycle having a member number of 5 to 10 together with a nitrogen atom, in which case the hydrogen atom bonded to the ring may be substituted with a substituent. good.

Examples of the substituents in R ⁵⁵ and R ⁵⁶ include the same substituents as the substituents in R ⁵¹ to R ⁵⁴ . When R ⁵⁵ and R ⁵⁶ are alaryl groups, the alkyl group contained therein may be further substituted with an aryl group.

When R ⁵⁵ and R ⁵⁶ are alkyl groups, the number of carbon atoms is preferably 1 to 20, more preferably 1 to 12, and even more preferably 1 to 10. From the viewpoint of visible light transmission and solubility in resins and solvents, R ⁵⁵ and R ⁵⁶ are linear or branched chains having 3 to 20 carbon atoms which may contain an oxygen atom between carbon atoms. Alternatively, a cyclic alkyl group is preferred. The number of carbon atoms of the alkyl group is more preferably 3 to 12 in the case of a linear chain, more preferably 3 to 10 in the case of a branched chain, and more preferably 5 to 10 in the case of a cyclic chain. When R ¹⁵ and R ¹⁶ have a substituent, the carbon number includes the carbon number of the substituent.
For R ⁵⁵ and R ⁵⁶ , for example, a group selected from the groups (1a) to (15a) is more preferable, and the group (1a) is particularly preferable.

R ⁵⁵ and R ⁵⁶ may be linked to each other to form a cycloheterocycle having 5 to 10 members together with a nitrogen atom. The cycloheterocycle may contain an oxygen atom in addition to the nitrogen atom as a ring constituent element. The number of members of the cycloheterocycle is preferably 5 or 6, and 5 is particularly preferable. When the hydrogen atom bonded to the cycloheterocycle is substituted, the substituents that substitute the hydrogen atom include a halogen atom, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms, an alkoxy group, and an aryl group having 6 to 20 carbon atoms. Alternatively, an alaryl group having 7 to 20 carbon atoms can be mentioned.

When the divalent group to which R ⁵⁵ and R ⁵⁶ are bonded is indicated by −Q−, the following groups (11) to (14) are specifically mentioned as —Q−.

-(CH ₂ ) ₄ -... (11)
-(CH ₂ ) ₅ -... (12)
-C (CH ₃ ) ₂ (CH ₂ ) ₂ C (CH ₃ ) _2- ... (13)
-C (CH ₃ ) ₂ (CH ₂ ) ₃ C (CH ₃ ) _2- ... (14)

As the squarylium compound (V), for example, a compound represented by the following formula (V-1) or a compound represented by the formula (V-2) is preferable. The squarylium compound (V-1) is a compound formed by linking R ⁵² and R ⁵³ to form a cyclopentadithiophene ring in the squarylium compound (V). The squarylium compound (V-2) is a compound in the squarylium compound (V) that contains a structure in which R ⁵² and R ⁵³ are not linked and two thiophene rings are bonded.

R ⁵¹ , R ⁵⁴ , R ⁵⁵ and R ⁵⁶ are similar to R ⁵¹ , R ⁵⁴ , R ⁵⁵ and R ⁵⁶ in formula (V), including preferred embodiments.
R ^52b and R ^53b are similar to R ⁵² and R ⁵³ in formula (V), except that they do not connect to each other to form a ring.

R ^52a and R ^53a are linear linear having 1 to 20 carbon atoms which may contain an oxygen atom between carbon atoms from the viewpoint of visible light transmission, light resistance, and solubility in resins and solvents. , Branched chain or cyclic alkyl groups are preferred. The number of carbon atoms of the alkyl group is more preferably 1 to 12 in the case of a linear chain, more preferably 3 to 10 in the case of a branched chain, and more preferably 5 to 10 in the case of a cyclic chain. For R ^52a and R ^53a , for example, a group selected from the groups (1a) to (15a) is more preferable, and a group (1a), a group (3a), or a group (9a) is particularly preferable.

From the viewpoint of transmittance and light resistance in the visible light region, R ^52a and R ^53a may have a phenyl group having 1 to 5 substituents or a phenyl group having 1 to 7 substituents. A good naphthyl group or an alkyl group having 1 to 10 carbon atoms is preferable. As the substituent of the phenyl group and the naphthyl group, an alkyl group having 1 to 12 carbon atoms which may contain an unsaturated bond or an oxygen atom between carbon and carbon atoms, an alkoxy group, or an alkylamino group (the number of carbon atoms of the alkyl group) 1 to 12), and a methyl group, a tertiary butyl group, a dimethylamino group, a methoxy group and the like are particularly preferable. The phenyl group and the naphthyl group are preferably unsubstituted or substituted with 1 to 3 hydrogen atoms.

Specific examples of the phenyl group which may have 1 to 5 substituents include groups (P1) to (P9).

Specific examples of the naphthyl group which may have 1 to 7 substituents include groups (N1) to (N9).

Specific examples of the compound (V-1) include the compounds shown in the following table. In addition, the compounds shown in the table below have the same meaning on the left and right sides of the squarylium skeleton.

Among these, the compound (V-1) is preferably a compound (V-1-5), (V-1-12) or the like from the viewpoint of transparency in the visible light region and solubility in a resin.

Specific examples of the compound (V-2) include the compounds shown in the following table. In addition, the compounds shown in the table below have the same meaning on the left and right sides of the squarylium skeleton.

The squarylium compound (V) can be produced by a known method. For example, it can be manufactured by the method described in International Publication No. 2019/230660.

<Iminium compound>
The imonium compound is preferably a compound represented by the following formula (A1) or formula (A2).

The symbols in the formulas (A1) and (A2) are as follows.
R ²⁰¹ to R ²⁰⁶ and R ²²¹ to R ²²⁶ each independently have an oxygen atom between a hydrogen atom, a halogen atom, a sulfo group, a hydroxy group, a cyano group, a nitro group, a carboxyl group, a phosphoric acid group, and a carbon atom. It may be an alkyl group or an alkoxy group having 1 to 20 carbon atoms which may be substituted, or an aryl group having 6 to 14 carbon atoms and an aralkyl group having 7 to 14 carbon atoms which may be substituted. Alternatively, it is a heterocyclic group having 3 to 14 members. However, groups in which a substituted or unsubstituted amino group is bonded to a phenyl group are excluded. Further, in R ²⁰¹ to R ²⁰⁶ and R ²²¹ to R ²²⁶ , two groups bonded to the same nitrogen atom may be bonded to each other to form a heterocycle having 3 to 8 members together with the nitrogen atom. The hydrogen atom bonded to the ring may be substituted with an alkyl group having 1 to 12 carbon atoms.

R ²⁰⁷ to R ²¹⁸ and R ²²⁷ to R ²³⁸ are independently substituted with a hydrogen atom, a halogen atom, an optionally substituted amino group, an amide group, a cyano group, a nitro group, a carboxyl group, or a halogen atom. It is an alkyl group or an alkoxy group having 1 to 12 carbon atoms which may be used. In R ²⁰⁷ to R ²¹⁸ and R ²²⁷ to R ²³⁸ , the two groups adjacent to each other may be bonded to each other to form a ring having 3 to 8 members together with the two carbon atoms of the phenyl group. The hydrogen atom to be bonded may be substituted with an alkyl group having 1 to 12 carbon atoms.

In R ²⁰¹ to R ²⁰⁶ and R ²²¹ to R ²²⁶ , an alkyl group or an alkoxy group having 1 to 20 carbon atoms which may be substituted, an aryl group having 6 to 14 carbon atoms which may be substituted, and 7 carbon atoms which may be substituted. As the substituent in the aralkyl group of to 14 or the heterocyclic group having 3 to 14 members, an amino group, a carboxyl group or a sulfo group which may be substituted with a halogen atom, a hydroxyl group or an alkyl group having 1 to 6 carbon atoms. , Cyano group and acyloxy group having 1 to 6 carbon atoms.

In the case where the ring is not formed, R ²⁰⁷ to R ²¹⁸ and R ²²⁷ to R ²³⁸ are each independently preferably a hydrogen atom, a halogen atom, or an alkyl group or an alkoxy group having 1 to 12 carbon atoms. The number of carbon atoms of the alkyl group or the alkoxy group is preferably 1 to 6, and more preferably 1 to 4.

In R ²⁰⁷ to R ²¹⁸ and R ²²⁷ to R ²³⁸ , the ring formed by bonding two groups adjacent to each other together with the two carbon atoms of the phenyl group may be an alicyclic ring or an aromatic ring. It may be a heterocycle. Examples of the hetero atom include a nitrogen atom, an oxygen atom, and a sulfur atom.

In R ²⁰⁷ to R ²¹⁸ and R ²²⁷ to R ²³⁸ , the combination in which two groups adjacent to each other are bonded is in the three phenyl groups bonded to the central nitrogen atom in the formulas (A1) and (A2). There are a total of 6 sets, 2 sets each. Specifically, in the formula (A1), there are 6 sets of R ²⁰⁷ and R ²⁰⁸ , R ²⁰⁹ and R ²¹⁰ , R ²¹¹ and R ²¹² , R ²¹³ and R ²¹⁴ , R ²¹⁵ and R ²¹⁶ , and R ²¹⁷ and R ²¹⁸ . Is. In the formula (A2), there are 6 sets of R ²²⁷ and R ²²⁸ , R ²²⁹ and R ²³⁰ , R ²³¹ and R ²³² , R ²³³ and R ²³⁴ , R ²³⁵ and R ²³⁶ , and R ²³⁷ and R ²³⁸ .

In R ²⁰⁷ to R ²¹⁸ of the formula (A1) and R ²²⁷ to R ²³⁸ of the formula (A2), the number of pairs to which two adjacent groups are bonded may be one set or two or more sets. All up to 6 pairs may be combined. For each of the three phenyl groups, it is preferable that one set each and a total of three sets are bonded.

As the divalent group to which the above two adjacent groups are bonded, specifically, one or two nitrogen atoms may be contained as a hetero atom, or an unsaturated bond may be formed between the atoms, and the number of carbon atoms is 1. Examples thereof include up to 6 alkylene groups. More specifically, the following groups (X-1) to (X-4) can be mentioned. The hydrogen atom of these divalent groups may be substituted with an alkyl group having 1 to 12 carbon atoms.

-(CH ₂ ) _n- (n is an integer from 1 to 6) ... (X-1)
-CH = CH-CH = CH-... (X-2)
-CH ₂ -CH = CH -... (X-3)
-N = CH-NH -... (X-4)

R ²⁰⁷ to R ²¹⁸ and R ²²⁷ to R ²³⁸ are each independently preferably a hydrogen atom, a halogen atom, or an alkyl group or an alkoxy group having 1 to 12 carbon atoms, and a hydrogen atom or an alkyl having 1 to 12 carbon atoms. A group or an alkoxy group is preferable. The number of carbon atoms of the alkyl group or the alkoxy group is preferably 1 to 6, and more preferably 1 to 4.

Also, R ²⁰¹ and R ²⁰⁷ , R ²⁰² and R ²¹⁰ , R ²⁰³ and R ²¹¹ , R ²⁰⁴ and R ²¹⁴ , R ²⁰⁵ and R ²¹⁵ , R ²⁰⁶ and R ²¹⁸ , R ²²¹ and R ²²⁷ , R ²²² and R ²³⁰ , R ²²³ and R ²³¹ and R ²²⁴ and R ²³⁴ , R ²²⁵ and R ²³⁵ , and R ²²⁶ and R ²³⁸ are 4 members together with a nitrogen atom bonded to a phenyl group and two carbon atoms of the phenyl group. A heterocycle of to 8 may be formed, and the hydrogen atom bonded to the ring may be substituted with an alkyl group having 1 to 12 carbon atoms.
Xa ^- and Xb ^- independently represent monovalent anions.

In the above, the alkyl group may be linear, branched, cyclic, or a combination of these structures. The same applies to the alkyl group when the following aryl group has an alkyl group and the alkyl group of the aralkyl group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like, and a fluorine atom and a chlorine atom are preferable.

In the above, the aryl group refers to a group bonded via a carbon atom constituting an aromatic ring (however, not including a hetero atom) of an aromatic compound, for example, a benzene ring, a naphthalene ring, biphenyl or the like. The aryl group includes a structure in which a hydrogen atom bonded to a ring-constituting atom other than a carbon atom contributing to the bond is substituted with an alkyl group, for example, a tolyl group or a xylyl group.

In the above, the aralkyl group refers to a group in which an alkyl group is bonded to an aromatic ring (however, it does not contain a hetero atom) and is bonded via a carbon atom constituting the alkyl group. The aralkyl group includes a structure in which a hydrogen atom bonded to a ring-constituting atom other than the atom to which the alkyl group contributing to the bond is bonded is substituted with an alkyl group.

In the above, the heterocyclic group is a group in which an atom constituting the ring is bonded via an atom constituting an alicyclic or aromatic ring composed of a carbon atom and an atom other than the carbon atom. The heterocyclic group includes a structure in which a hydrogen atom bonded to a ring-constituting atom other than the atom contributing to the bond is substituted with an alkyl group. Examples of the atom other than the carbon atom contained in the heterocycle include an oxygen atom, a nitrogen atom, and a sulfur atom, and the number is preferably 1 or 2.

As Xa- ^and Xb- ^{, Cl- ,} Br-, I- ^, F- ^, ClO _4- ^, BF _4- ^, PF _6- ^, SbF _6- ^, CF ₃ SO _3- ^, CH ₃ C, respectively. ₆ H ₄ SO _3- ^, N [SO ₂ R _f ] _2- ^, C [SO ₂ R _f ] _3- ^, etc. may be mentioned.

Here, R _f is a fluoroalkyl group having 1 to 4 carbon atoms, preferably a fluoroalkyl group having 1 to 2 carbon atoms, and more preferably a fluoroalkyl group having 1 carbon atom. When the number of carbon atoms is within the above range, durability such as heat resistance and moisture resistance, and solubility in an organic solvent described later are good. Examples of such R _f include perfluoroalkyl groups such as -CF ₃ , -C ₂ F ₅ , -C ₃ F ₇ , -C ₄ F ₉ , and -C ₂ F ₄ H, -C ₃ F ₆ . H, -C ₂ F ₈ H and the like can be mentioned.

From the viewpoint of moisture resistance, the fluoroalkyl group is preferably a perfluoroalkyl group, more preferably a trifluoromethyl group.

As Xa- ^and Xb- ^, I- ^, BF ^4- , SbF _6- ^, PF _6- ^, ClO _4- ^, N [SO ₂ CF ₃ ] _2- ^, C [SO ₂ CF ₃ ] ₃ are independent of each other. -E ^, etc. are preferable, and SbF _6- , PF ₆ ^{- and} N [SO ₂ CF ₃ ] _2- are more preferable, ^and SbF _6- ^, N [SO ₂ CF ₃ ] ₂ ^- is particularly preferable. Further, from the viewpoint of light durability, BF ^4- , PF _6- ^, and N [SO ₂ CF ₃ ^] _2- are preferable.

The content of the NIR dye (IR) in the resin film is preferably 0.1 to 25 parts by mass, more preferably 0.3 to 15 parts by mass with respect to 100 parts by mass of the resin. When two or more kinds of compounds are combined, the above-mentioned content is the sum of each compound.
When the NIR dye (IR) contains the compounds (A) to (C), the content of the compound (A) is preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the resin, and the content of the compound (B) is contained. The amount is preferably 0.1 to 5 parts by mass, and the content of the compound (C) is preferably 0.1 to 5 parts by mass.

<Other pigments>
The resin film may contain other dyes such as UV dyes in addition to the NIR dye.
Specific examples of the UV dye include oxazole-based, merocyanine-based, cyanine-based, naphthalimide-based, oxadiazole-based, oxazine-based, oxazolidine-based, naphthalic acid-based, styryl-based, anthracene-based, cyclic carbonyl-based, and triazole-based. Pigments can be mentioned. In addition, one type of UV dye may be used alone, or two or more types may be used in combination.

<Base material composition>
The base material in this filter may have a single-layer structure or a multi-layer structure. The material of the base material may be an organic material or an inorganic material as long as it is a transparent material that transmits visible light of 400 to 700 nm, and is not particularly limited.
When the base material has a single-layer structure, a resin base material composed of a resin film containing a resin and a NIR dye (IR) is preferable.
When the base material has a multi-layer structure, a composite base material in which a resin film containing a NIR dye (IR) is laminated on at least one main surface of the support is preferable. At this time, the support is preferably made of a transparent resin or a transparent inorganic material.

The resin is not limited as long as it is a transparent resin, and is not limited to polyester resin, acrylic resin, epoxy resin, en-thiol resin, polycarbonate resin, polyether resin, polyarylate resin, polysulfone resin, polyether sulfone resin, and polyparaphenylene. One or more transparent resins selected from resins, polyarylene ether phosphine oxide resins, polyamide resins, polyimide resins, polyamideimide resins, polyolefin resins, cyclic olefin resins, polyurethane resins, polystyrene resins and the like are used. One of these resins may be used alone, or two or more of these resins may be mixed and used.
From the viewpoint of optical properties of the resin film, glass transition point (Tg), and adhesion, one or more resins selected from polyimide resin, polycarbonate resin, polyester resin, and acrylic resin are preferable.

When a plurality of compounds are used as the NIR dye (IR) and other dyes, they may be contained in the same resin film, or may be contained in different resin films.

As the transparent inorganic material, glass or a crystalline material is preferable.
Glasses that can be used for the support include absorbent glass (near-infrared absorbing glass) containing copper ions in fluoride-based glass, phosphate-based glass, etc., soda lime glass, borosilicate glass, non-alkali glass, and quartz. Examples include glass.
As the glass, phosphate-based glass and fluoride-based glass are preferable from the viewpoint of being able to absorb infrared light (particularly 900 to 1200 nm). The "phosphate-based glass" also includes silicate glass in which a part of the skeleton of the glass is composed of SiO ₂ .

As for glass, alkali metal ions (for example, Li ion and Na ion) having a small ion radius existing on the main surface of the glass plate are converted into alkali ions having a larger ion radius (for example) by ion exchange at a temperature below the glass transition point. , It is Na ion or K ion for Li ion, and K ion for Na ion.) You may use the chemically strengthened glass obtained by exchanging it.

Examples of the crystal material that can be used for the support include birefringent crystals such as quartz, lithium niobate, and sapphire.

As the support, an inorganic material is preferable, and glass and sapphire are particularly preferable, from the viewpoint of shape stability related to long-term reliability such as optical properties and mechanical properties, and handleability at the time of filter manufacturing.

For the resin film, a dye (IR), a resin or a raw material component of the resin, and each component to be blended as necessary are dissolved or dispersed in a solvent to prepare a coating liquid, and this is applied to a support. It can be formed by working, drying, and then curing if necessary. The support may be a support included in the present filter, or may be a peelable support used only when forming a resin film. The solvent may be a dispersion medium that can be stably dispersed or a solvent that can be dissolved.

Further, the coating liquid may contain a surfactant for improving voids due to minute bubbles, dents due to adhesion of foreign substances, repellency in the drying step, and the like. Further, for the coating of the coating liquid, for example, a dip coating method, a cast coating method, a spin coating method or the like can be used. A resin film is formed by applying the above coating liquid on the support and then drying it. When the coating liquid contains a raw material component of a transparent resin, further curing treatment such as heat curing and photocuring is performed.

The resin film can also be manufactured in the form of a film by extrusion molding. When the base material has a single-layer structure (resin base material) made of a resin film containing a dye (IR), the resin film may be used as it is as the base material. When the base material has a multi-layer structure (composite base material) having a support and a resin film containing a dye (IR) laminated on at least one main surface of the support, this film is laminated on the support. A base material can be manufactured by integrating by thermocompression bonding or the like.

The resin film may have one layer or two or more layers in the optical filter. When having two or more layers, each layer may have the same configuration or may be different.

The thickness of the resin film is preferably 20 to 150 μm when the base material has a single-layer structure (resin base material) made of a resin film containing a dye (IR).
When the base material is a multi-layer structure (composite base material) having a support and a resin film containing a dye (IR) laminated on at least one main surface of the support, the thickness of the resin film is determined. It is preferably 0.3 to 20 μm. When the optical filter has two or more resin films, the total thickness of each resin film is preferably in the above range.

The shape of the base material is not particularly limited, and may be block-shaped, plate-shaped, or film-shaped.
The thickness of the base material is preferably 300 μm or less from the viewpoint of reducing warpage during film formation of the dielectric multilayer film and reducing the height of the optical element, and is preferably 50 when the base material is a resin base material made of a resin film. It is about 300 μm, and when the base material is a composite base material including a support and a resin film, it is preferably 50 to 300 μm.

As other components, the filter may include, for example, a component (layer) that provides absorption by inorganic fine particles or the like that controls the transmission and absorption of light in a specific wavelength range. Specific examples of the inorganic fine particles include ITO (Indium Tin Oxides), ATO (Antimony-topped Tin Oxides), cesium tungstate, lanthanum borate and the like. The ITO fine particles and the cesium tungstate fine particles have high visible light transmittance and have light absorption over a wide range in the infrared wavelength region exceeding 1200 nm, and thus can be used when such infrared light shielding properties are required. ..

Next, the present invention will be described in more detail with reference to Examples.
An ultraviolet-visible spectrophotometer (UH-4150 type manufactured by Hitachi High-Technologies Corporation) was used for the measurement of each optical characteristic.
The optical characteristics when the incident angle is not particularly specified are values measured at an incident angle of 0 degrees (perpendicular to the main surface of the optical filter).

The dyes used in each example are as follows.
Compound 1 (Squarylium compound): Synthesized according to US Patent Application Publication No. 2014/0061505 and International Publication No. 2014/088063.
Compound 2 (phthalocyanine compound): Synthesized based on Japanese Patent No. 4081149.
Compound 3 (Squarylium compound): Synthesized according to International Publication No. 2017/135359.
Compounds 4 to 6 (cyanine compounds): Synthesized based on Days and pigments 73 (2007) 344-352.
Compound 7 (Squarylium compound): Synthesized according to International Publication No. 2019/230660.
Compound 8 (diimonium compound): Synthesized based on JP-A-2014-25016.

<Optical characteristics of IR dye>
A polyimide resin (C-3G30G manufactured by Mitsubishi Gas Chemical Company, Inc.) was dissolved in an organic solvent (cyclohexanone: γ-butyrolactone = 1: 1 mass ratio) at a concentration of 8.5% by mass.
To the solution of the polyimide resin prepared above, each dye compound was added to 100 parts by mass of the resin so as to be 6 parts by mass, and the mixture was stirred for 2 hours while heating at 50 ° C. A dye-containing resin solution was applied to a glass substrate (alkaline glass, D263 manufactured by Schott) and dried to obtain a resin film (coating film) having a film thickness of 1 μm.
Using the spectral transmittance curve and the spectral reflectance curve of this glass plate with a resin film, a spectral internal transmittance curve was calculated and standardized so that the transmittance at the maximum absorption wavelength was 10%.
The optical characteristics are shown in the table below.

<Example 1-1 to Example 1-5: Optical characteristics of resin film>
A polyimide resin (C-3G30G manufactured by Mitsubishi Gas Chemical Company, Inc.) was dissolved in an organic solvent (cyclohexanone: γ-butyrolactone = 1: 1 mass ratio) at a concentration of 8.5% by mass.
To the solution of the polyimide resin prepared above, each compound was added so as to have the content (parts by mass) shown in the table below with respect to 100 parts by mass of the resin, and the mixture was stirred for 2 hours while heating at 50 ° C. A dye-containing resin solution was applied to a glass substrate (alkaline glass, D263 manufactured by Schott) and dried to obtain a resin film (coating film) having a film thickness of 2 μm.
With respect to the obtained resin film, transmission spectroscopy in the incident direction of 0 deg and reflection spectroscopy in the incident direction of 5 deg were measured in the wavelength range of 350 nm to 1200 nm. The transmittance is shown by the internal transmittance expressed by the following formula.
Internal transmittance = measured transmittance / (100-reflectance) * 100
The optical characteristics are shown in the table below.
Examples 1-1 to 1-5 are reference examples.

In Examples 1-1 to 1-3, the visible light transmittance is high because the dye is blended only in the amount necessary for absorbing the near-infrared light region where light leakage may occur in the multilayer film.
In Example 1-4, since the amount of dye to be blended is small, the multilayer film does not completely absorb the near-infrared light region where light leakage may occur.
In Example 1-5, the absorption width in the near-infrared light region is wide, but the visible light transmittance is low. It is probable that as a result of increasing the amount of the dye added to widen the absorption range, the visible light region was also absorbed.

<Example 2-1 to Example 2-2: Optical characteristics of dielectric multilayer film>
We designed a dielectric multilayer film 1 with a total film thickness of 3.94 μm in which 32 layers of dio ₂ film and SiO ₂ film are alternately laminated, and a dielectric multilayer film 2 having a total film thickness of 4.94 μm in which 40 layers are laminated.
The optical characteristics of the dielectric multilayer film 1 and the dielectric multilayer film 2 are shown in the table below.
Further, the spectral transmittance curves of the dielectric multilayer film 1 and the dielectric multilayer film 2 are shown in FIGS. 5 and 6, respectively.
In addition, Example 2-1 and Example 2-2 are reference examples.

The dielectric multilayer film 1 has a small ripple, but light leakage occurs after 780 nm.
The dielectric multilayer film 2 has a large ripple, but light leakage hardly occurs after 780 nm.

<Example 3-1: Optical characteristics of optical filter>
The dielectric multilayer film 1 of Example 2-1 was laminated on the main surface of a glass substrate (alkaline glass, D263 manufactured by Schott). A dielectric multilayer film (antireflection film) in which the resin film of Example 1-1 is formed on the other main surface of the glass substrate by spin coating, and SiO ₂ and TiO ₂ are alternately laminated on the resin film. Was formed by vapor deposition to prepare an optical filter 1.

<Example 3-2: Optical characteristics of optical filter>
An optical filter 2 was produced in the same manner as in Example 3-1 except that the dielectric multilayer film 2 of Example 2-2 was laminated in place of the dielectric multilayer film 1 of Example 2-1.

<Example 3-3: Optical characteristics of optical filter>
An optical filter 3 was produced in the same manner as in Example 3-1 except that the resin film of Example 1-5 was formed in place of the resin film of Example 1-1.

The optical characteristics of the optical filters 1 to 3 are shown in the table below.
Example 3-1 is an example, and Examples 3-2 and 3-3 are comparative examples.

The optical filter of Example 3-1 has high visible light transmittance, small ripple at a high incident angle of 40 degrees, and can achieve both light shielding in a long wavelength region including a near infrared light region of 750 to 1000 nm. ..
The optical filter of Example 3-2 has a large dependence on the incident angle of the dielectric multilayer film, and cannot realize low ripple at a high incident angle of 40 degrees.
In the optical filter of Example 3-3, the transmittance of visible light was greatly reduced due to excessive absorption by the dye.

The optical filter of the present invention has excellent transmission of visible light and has good near-infrared light shielding characteristics in which changes in the shielding property of near-infrared light are suppressed at a high incident angle. In recent years, the performance has been improved, and it is useful for applications of information acquisition devices such as cameras and sensors for transport aircraft.

1A, 1B, 1C, 1D ... Optical filter, 10 ... Base material, 11 ... Support, 12 ... Resin film, 30 ... Dielectric multilayer film

Claims (9)

An optical filter comprising a base material and a dielectric multilayer film laminated as an outermost layer on at least one main surface side of the base material.
The base material has a resin film containing a dye (IR) and a resin, and has a resin film.
The dye (IR) has a maximum absorption wavelength at 680-1000 nm in dichloromethane.
An optical filter in which the optical filter satisfies all of the following optical characteristics (i-1) to (i-10).
(I-1) At a wavelength of 450 to 500 nm, the average reflectance R _{450-500 (5 deg) AVE} at an incident angle of 5 degrees is 3% or less, and the average reflectance R _{450-500 (} 40 deg) at an incident angle of 40 degrees. _{) AVE} is 5% or less (i-2) Average reflectance at an incident angle of 5 degrees at a wavelength of 500 to 580 nm R _{500-580 (5 deg) AVE} is 2.5% or less and an average at an incident angle of 40 degrees. Reflectivity R _{500-580 (40 deg) AVE} is 4% or less (i-3) R _{450-500 (5 deg) AVE} > R _{500-580 (5 deg) AVE} and R _{450-500 (40 deg) AVE} > At a wavelength of (i-4) 450 to 580 nm that satisfies the relationship of R _{500-580 (40 deg) AVE} , the maximum reflectance R _{450-580 (5 deg) MAX} at an incident angle of 5 degrees is 4% or less and the incident angle. Maximum reflectivity at 40 degrees R _{450-580 (40 deg) MAX} is 6% or less (i-5) Difference between the transmittance at an incident angle of 0 degrees and the transmittance at an incident angle of 40 degrees at a wavelength of 450 to 500 nm. The maximum value of is 6% or less (i-6), and the maximum value of the difference between the transmittance at an incident angle of 0 degrees and the transmittance at an incident angle of 40 degrees is 5% or less (i-7) at a wavelength of 500 to 580 nm. Average transmission T _{450-580 (0deg) AVE} at an incident angle of 0 degrees at a wavelength of 450 to 580 nm is 88% or more (i-8) Transmission is 20% at an incident angle of 0 degrees at a wavelength of 600 to 800 nm. When the absolute value of the difference between the wavelength and the wavelength at which the transmittance is 20% at an incident angle of 40 degrees is 10 nm or less (i-9) at a wavelength of 600 to 800 nm, the wavelength at which the transmittance is 20% at an incident angle of 0 degrees is At a (i-10) wavelength range of 640 to 690 nm and a wavelength of 750 to 1000 nm, the maximum transmission rate _{T750-1000 (0deg) MAX} at an incident angle of 0 degrees is 1% or less, and the maximum transmission is at an incident angle of 40 degrees. Rate _{T750-1000 (40deg) MAX} is 1% or less The optical filter according to claim 1, wherein the resin film satisfies all of the following optical characteristics (ii-1) to (ii-6).
(Ii-1) The average internal transmittance T _{450-580 AVE} at a wavelength of 450 to 580 nm is 88% or more. (Ii-2) At a wavelength of 600 to 700 nm, the wavelength at which the internal transmittance is 20% is in the range of 640 to 690 nm. (Ii-3) Internal transmittance T ₇₀₀ at a wavelength of 700 nm is 1% or less (ii-4) Internal transmittance T ₇₅₀ at a wavelength of 750 nm is 10% or less (ii-5) Internal transmittance T ₈₀₀ at a wavelength of 800 nm is 20%. Below (ii-6) Internal transmittance T ₉₅₀ at a wavelength of 950 nm is 60% or more and 95% or less. The optical filter according to claim 1 or 2, wherein the dielectric multilayer film satisfies all of the following optical characteristics (iv-1) to (iv-8).
(Iv-1) At a wavelength of 450 to 580 nm, the average transmittance T _{450-580 (0 deg) AVE} at an incident angle of 0 degrees is 90% or more, and the average transmittance T _{450-580 (} 40 deg) at an incident angle of 40 degrees. _{) When the AVE} is 90% or more (iv-2) at a wavelength of 450 to 500 nm, the absolute value of the difference between the average transmittance at an incident angle of 0 degrees and the average transmittance at an incident angle of 40 degrees is 3% or less (iv-3). ) The absolute value of the difference between the average transmittance at an incident angle of 0 degrees and the average transmittance at an incident angle of 40 degrees is 2% or less at a wavelength of 500 to 580 nm (iv-4). The maximum value of the difference between the transmittance at 10 degrees and the transmittance at an incident angle of 40 degrees is 6% or less (iv-5). At a wavelength of 500 to 580 nm, the transmittance at an incident angle of 0 degrees and the transmittance at an incident angle of 40 degrees. When the maximum value of the difference from the transmittance is 5% or less (iv-6) at a wavelength of 600 to 800 nm, the wavelength at which the transmittance is 20% at an incident angle of 0 degrees is in the range of 720 to 770 nm (iv-7). Maximum transmittance at an incident angle of 0 degrees at a wavelength of 780 to 850 nm T _{780-850 (0 deg) MAX} is 4% or more and less than 10% (iv-8) Maximum transmittance at an incident angle of 40 degrees at a wavelength of 900 to 980 nm T _{900-980 (40 deg) MAX} is 1% or more and less than 5% The dye (IR) is
Compound (A) having the maximum absorption wavelength in dichloromethane above 690 nm and below 735 nm,
Compound (B) having the maximum absorption wavelength in dichloromethane above 735 nm and below 835 nm,
The optical filter according to any one of claims 1 to 3, which contains one or more compounds selected from the compound (C) having a maximum absorption wavelength of 900 nm or more and 1000 nm or less in dichloromethane. The optical filter according to claim 4, wherein the maximum value of the difference between the maximum absorption wavelength of the compound (A) and the maximum absorption wavelength of the compound (B) is 40 nm or more. The dye (IR) has a spectral internal transmittance measured by dissolving the dye (IR) in the resin so that the internal transmittance at the maximum absorption wavelength is 10% among the resins constituting the resin film. The optical filter according to any one of claims 1 to 5, which satisfies the following characteristic (iii-1) in the curve.
(Iii-1) When the maximum absorption wavelength in the resin is D [nm] and the average internal transmittance at 450 to 580 nm is E, E> 100- (D / 100). The compound (A) is selected one or more from either a squarylium compound or a cyanine compound, the compound (B) is selected from one or more of a squarylium compound or a cyanine compound, and the compound (C) is selected from one or more. The optical filter according to any one of claims 4 to 6, wherein one or more of the squalylium compound, the cyanine compound, and the immonium compound are selected. The optical filter according to any one of claims 1 to 7, wherein the base material includes a support and the resin film, and the resin film is laminated on at least one main surface of the support. The optical filter according to any one of claims 1 to 8, wherein the resin is a polyimide resin.

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