Optical filter

Abstract

To provide an optical filter with high transmittance of visible light and high blocking of near-infrared light capable of suppressing ripples even at high angles of incidence while suppressing the change in blocking ability at high incidence angles of near-infrared light.SOLUTION: The optical filter includes: a substrate; and a dielectric multilayer film laminated on at least one of the main surfaces of the substrate. The substrate has at least one layer of a resin film containing a dye (IR) and a resin with a total thickness of 0.3 to 20 μm. The optical filter is an optical filter that satisfies the spectral transmittance curve at incidence angles of 0 degrees, 5 degrees, and 40 degrees satisfies all of the specific optical characteristics (i-1), (i-2), (i-4), (i-7) to (i-10).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] 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. [Background technology]

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

[0003] Such optical filters can take various forms, such as reflective filters that alternately stack dielectric thin films with different refractive indices on one or both sides of a transparent substrate (dielectric multilayer film) and reflect the light to be blocked by utilizing light interference.

[0004] Optical filters with dielectric multilayer films have several problems. Because the optical thickness of the dielectric multilayer film changes with the angle of incidence of light, the spectral transmittance curve changes depending on the angle of incidence, near-infrared light, which should have high reflectivity at high angles of incidence, becomes highly transmittant, and noise is generated by near-infrared light reflected by the dielectric multilayer film. Using such filters may affect the spectral sensitivity of solid-state image sensors. In particular, with the recent trend towards lower-profile camera modules, use under high-angle conditions is anticipated.

[0005] Furthermore, in dielectric multilayer films, a drastic change in transmittance (ripple) can occur due to interference caused by reflected light at each layer interface, depending on the number of layers stacked. Ripple also increases with larger incident angles. Dielectric multilayer films used in optical filters that transmit visible wavelength light and block near-infrared wavelength light are designed to transmit visible light and block longer wavelength light beyond the near-infrared. Conventional dielectric multilayer films are designed to suppress light loss in the near-infrared region, but ripple occurs in the visible light region, and the incident angle considered is limited to approximately 30 degrees.

[0006] Patent Document 1 describes a near-infrared cut filter comprising a dielectric multilayer film, in which ripple in the visible light region is suppressed at high incidence angles. Patent Document 2 describes an optical filter that reduces incident angle dependence without requiring a dielectric multilayer film by combining various near-infrared absorbing dyes. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2019-120942 [Patent Document 2] Japanese Patent Publication No. 2019-32371 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, the near-infrared cut filter described in Patent Document 1 exhibits a change in spectral transmittance curve at high incidence angles, resulting in a change in shielding performance in the near-infrared region. The optical filter described in Patent Document 2 has low transmittance in the visible light region because visible light is also absorbed by the dyes used in large quantities to ensure shielding and incident angle dependence in the near-infrared light region.

[0009] The present invention aims to provide an optical filter that has high transmittance of visible light and high shielding of near-infrared light, suppresses ripple even at high incidence angles, and suppresses changes in shielding performance at high incidence angles of near-infrared light. [Means for solving the problem]

[0010] The present invention provides an optical filter having the following configuration. [1] An optical filter comprising a substrate and a dielectric multilayer film laminated on at least one main surface side of the substrate, The substrate has at least one layer of resin film containing a dye (IR) and a resin, The total thickness of the resin film is 0.3 to 20 μm, The optical filter is an optical filter that satisfies all of the following optical characteristics (i-1), (i-2), (i-4), (i-7) to (i-10). (i-1) On at least one surface of the optical filter, the average reflectance R at a wavelength of 450 to 500 nm and an incident angle of 5 degrees 450-500(5deg)AVE is 3% or less, and the average reflectance R at an incident angle of 40 degrees 450-500(40deg)AVE is 5% or less (i-2) On at least one surface of the optical filter, the average reflectance R at a wavelength of 500 to 580 nm and an incident angle of 5 degrees 500-580(5deg)AVE is 2.5% or less, and the average reflectance R at an incident angle of 40 degrees 500-580(40deg)AVE is 4% or less (i-4) On at least one surface of the optical filter, the maximum reflectance R at a wavelength of 450 to 580 nm and an incident angle of 5 degrees 450-580(5deg)MAX is 4% or less, and the maximum reflectance R at an incident angle of 40 degrees 450-580(40deg)MAX is 6% or less (i-7) In the wavelength range of 450 to 580 nm, the average transmittance T at an incident angle of 0 degrees 450-580(0deg)AVE is 88% or more (i-8) In the wavelength range of 600 to 800 nm, the absolute value of the difference between the wavelength at which the transmittance becomes 20% at an incident angle of 0 degrees and the wavelength at which the transmittance becomes 20% at an incident angle of 40 degrees is 10 nm or less (i-9) In the wavelength range of 600 to 800 nm, the wavelength at which the transmittance becomes 20% at an incident angle of 0 degrees is in the range of 640 to 690 nm (i-10) In the wavelength range of 750 to 1000 nm, the maximum transmittance T at an incident angle of 0 degrees 750-1000(0deg)MAX is 1% or less, and the maximum transmittance T at an incident angle of 40 degrees 750-1000(40deg)MAX is 1% or less

Advantages of the Invention

[0011] According to the present invention, there is provided an optical filter having high transmittance of visible light and high shielding property of near-infrared light, suppressing ripples even at a high incident angle, and suppressing changes in the shielding property at a high incident angle of near-infrared light.

Brief Description of the Drawings

[0012] [Figure 1] Figure 1 is a schematic cross-sectional view showing an example of an optical filter according to one embodiment. [Figure 2] Figure 2 is a schematic cross-sectional view showing another example of an optical filter according to one embodiment. [Figure 3] Figure 3 is a schematic cross-sectional view showing another example of an optical filter according to one embodiment. [Figure 4] Figure 4 is a schematic cross-sectional view showing another example of an optical filter according to one embodiment. [Figure 5] Figure 5 shows the spectral transmittance curve of dielectric multilayer film 1 in Example 2-1. [Figure 6] Figure 6 shows the spectral transmittance curve of the dielectric multilayer film 2 of Example 2-2. [Modes for carrying out the invention]

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

[0014] In this specification, internal transmittance is defined by the formula {measured transmittance / (100-reflectance)}×100, which is the transmittance obtained by subtracting the effect of interfacial reflection from the measured transmittance. In this specification, the transmittance of a substrate, the transmittance of a resin film (including cases where the dye is contained in the resin), and the spectral transmission measured by dissolving the dye in a solvent such as dichloromethane all refer to "internal transmittance" even when the term "transmittance" is used. On the other hand, the transmittance of an optical filter having a dielectric multilayer film is the measured transmittance.

[0015] In this specification, for a particular wavelength range, a transmittance of, for example, 90% or more means that the transmittance does not fall below 90% across the entire wavelength range, i.e., the minimum transmittance in that wavelength range is 90% or more. Similarly, for a particular wavelength range, a transmittance of, for example, 1% or less means that the transmittance does not exceed 1% across the entire wavelength range, i.e., the maximum transmittance in that wavelength range is 1% or less. The same applies to internal transmittance. The average transmittance and average internal transmittance in a particular wavelength range are the arithmetic mean of the transmittance and internal transmittance for every 1 nm in that wavelength range. Optical properties can be measured using an ultraviolet-visible spectrophotometer. In this specification, the symbol "~" used to indicate a numerical range includes both upper and lower limits.

[0016] <Optical filters> An optical filter according to one embodiment of the present invention (hereinafter also referred to as "this filter") comprises a substrate and a dielectric multilayer film laminated as the outermost layer on at least one main surface side of the substrate, and is an optical filter that satisfies specific optical properties described later. 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 an NIR dye. By containing a dye that absorbs near-infrared light in the substrate, the absorption characteristics of the substrate can compensate for the deterioration of the optical properties of the dielectric multilayer film at high incidence angles, such as light loss and noise in the near-infrared region. Each dye and resin will be described later.

[0017] An example of the configuration of this filter will be explained using the drawings. Figures 1 to 4 are schematic cross-sectional views showing an example of an optical filter according to one embodiment. The optical filter 1A shown in Figure 1 is an example in which a dielectric multilayer film 30 is provided on one main surface side of the substrate 10. Note that "having a specific layer on the main surface side of the substrate" is not limited to cases where the layer is in contact with the main surface of the substrate, but also includes cases where another functional layer is provided between the substrate and the layer.

[0018] The optical filter 1B shown in Figure 2 is an example in which a dielectric multilayer film 30 is present on both main surfaces of the substrate 10.

[0019] The optical filter 1C shown in Figure 3 is an example in which the substrate 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 dielectric multilayer films 30 on top of the resin film 12 and on the main surface side of the support 11 where the resin film 12 is not laminated.

[0020] The optical filter 1D shown in Figure 4 is an example in which the substrate 10 has a support 11 and a resin film 12 laminated on both main surfaces of the support 11. The optical filter 1D further has a dielectric multilayer film 30 on each of the resin films 12.

[0021] The optical filter of the present invention satisfies all of the following optical characteristics (i-1) to (i-10). (i-1) The average reflectance R at an incident angle of 5 degrees in the wavelength range of 450-500 nm. 450-500(5deg)AVE The average reflectance R at an incident angle of 40 degrees is 3% or less. 450-500(40deg)AVE less than 5% (i-2) The average reflectance R at an incident angle of 5 degrees in the wavelength range of 500-580 nm. 500-580(5deg)AVE The average reflectance R at an incident angle of 40 degrees is 2.5% or less. 500-580(40deg)AVE less than 4% (i-3) The above R 450-500(5deg)AVE >The aforementioned R 500-580(5deg)AVE Furthermore, the R 450-500(40deg)AVE >The aforementioned R 500-580(40deg)AVE Satisfying the relationship (i-4) Maximum reflectance R at an incident angle of 5 degrees in the wavelength range of 450-580 nm. 450-580(5deg)MAX The maximum reflectance R is 4% or less and at an incident angle of 40 degrees. 450-580(40deg)MAX less than 6% (i-5) In the wavelength range of 450-500 nm, the maximum difference between the transmittance at an incident angle of 0 degrees and the transmittance at an incident angle of 40 degrees should be 6% or less. (i-6) In the wavelength range of 500-580 nm, the maximum difference between the transmittance at an incident angle of 0 degrees and the transmittance at an incident angle of 40 degrees should be 5% or less. (i-7) Average transmittance T at an incident angle of 0 degrees in the wavelength range of 450-580 nm. 450-580(0deg)AVE over 88% (i-8) In the wavelength range of 600-800 nm, the absolute difference between the wavelength at which the transmittance is 20% at an incident angle of 0 degrees and the wavelength at which the transmittance is 20% at an incident angle of 40 degrees is 10 nm or less. (i-9) In the wavelength range of 600-800 nm, the wavelength at which the transmittance is 20% at an incident angle of 0 degrees is in the range of 640-690 nm. (i-10) Maximum transmittance T at an incident angle of 0 degrees in the wavelength range of 750 to 1000 nm. 750-1000(0deg)MAX The transmittance is 1% or less, and the maximum transmittance at an incident angle of 40 degrees is T. 750-1000(40deg)MAX less than 1%

[0022] This filter, which satisfies all of the optical characteristics (i-1) to (i-10), is an optical filter that excels in the transmission of visible light and the shielding of near-infrared light, and suppresses ripple generation and changes in near-infrared light shielding performance at a high incident angle of 40 degrees.

[0023] Satisfying optical properties (i-1), (i-2), and (i-4) means that the reflectance in the visible light region is sufficiently low. In the optical properties (i-1), R 450-500(5deg)AVE Preferably 2.5% or less, R 450-500(40deg)AVE It is preferably 4.5% or less. In the optical properties (i-2), R 500-580(5deg)AVE Preferably 2% or less, R 500-580(40deg)AVE It is preferably 3.5% or less. In the optical properties (i-4), R 450-580(5deg)MAX Preferably 3.5% or less, R 450-580(40deg)MAX It is preferably 5.5% or less.

[0024] Satisfying the optical properties (i-3) means that the reflectivity in the green band, which is particularly important for the visibility of the imaging device's sensor, is low.

[0025] Satisfying optical property (i-7) means that the transmittance in the visible light region is high, and satisfying optical properties (i-1), (i-2), and (i-4) to (i-6) means that ripple is suppressed even at high incidence angles.

[0026] The optical properties (i-5) are preferably 5.5% or less, more preferably 5% or less. The optical properties (i-6) are preferably 4.5% or less, more preferably 4% or less.

[0027] T 450-580(0deg)AVE This is preferably 89% or more, and more preferably 90% or more.

[0028] Satisfying optical properties (i-8) means that in the near-infrared light absorption band of 600-800 nm wavelength, there is little shift (i.e., change in near-infrared light shielding) even at high incident angles, resulting in excellent color reproduction. The optical properties (i-8) are preferably 8 nm or less, more preferably 6 nm or less.

[0029] Satisfying the optical properties (i-9) means that the infrared band can be blocked and visible transmitted light can be efficiently captured. The optical properties (i-9) are preferably in the range of 645 to 685 nm, more preferably in the range of 650 to 680 nm.

[0030] By satisfying the optical properties (i-10), it means that excellent light shielding is achieved in the near-infrared to long-wavelength region (wavelengths 750-1000 nm) at both a high incident angle of 0 degrees and a high incident angle of 40 degrees. 750-1000(0deg)MAX The amount is preferably 0.95% or less, and more preferably 0.9% or less. 750-1000(40deg)MAX The concentration is preferably 0.95% or less, and more preferably 0.9% or less.

[0031] <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.

[0032] In this filter, it is preferable that the dielectric multilayer film satisfies all of the following optical properties (iv-1) to (iv-8). (iv-1) Average transmittance T at an incident angle of 0 degrees in the wavelength range of 450-580 nm 450-580(0deg)AVE The transmittance is 90% or more, and the average transmittance at an incident angle of 40 degrees is T 450-580(40deg)AVEover 90% (iv-2) In the wavelength range of 450-500 nm, the absolute 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) In the wavelength range of 500-580 nm, the absolute 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. (iv-4) In the wavelength range of 450-500 nm, the maximum difference between the transmittance at an incident angle of 0 degrees and the transmittance at an incident angle of 40 degrees should be 6% or less. (iv-5) In the wavelength range of 500-580 nm, the maximum difference between the transmittance at an incident angle of 0 degrees and the transmittance at an incident angle of 40 degrees should be 5% or less. (iv-6) In the wavelength range of 600-800 nm, the wavelength at which the transmittance is 20% at an incident angle of 0 degrees is in the range of 720-770 nm. (iv-7) Maximum transmittance T at an incident angle of 0 degrees in wavelengths of 780-850 nm 780-850(0deg)MAX 4% to less than 10% (iv-8) Maximum transmittance T at an incident angle of 40 degrees in wavelengths of 900-980 nm 900-980(40deg)MAX 1% or more but less than 5%

[0033] Satisfying optical property (iv-1) means that the visible light spectrum is transmitted well at both a 0-degree incident angle and a high incident angle of 40 degrees. T 450-580(0deg)AVE The percentage is preferably 91% or more, and more preferably 92% or more. T 450-580(40deg)AVE Preferably, it is 90.5% or more, and more preferably 91% or more.

[0034] Satisfying optical properties (iv-2) to (iv-5) means that ripple generation in the visible light region is suppressed even at a high incidence angle of 40 degrees. The optical properties (iv-2) are preferably 2.5% or less, more preferably 2% or less. The optical properties (iv-3) are preferably 1.6% or less, more preferably 1.2% or less. The optical properties (iv-4) are preferably 5.5% or less, more preferably 5% or less. The optical properties (iv-5) are preferably 4.5% or less, more preferably 4% or less.

[0035] Satisfying optical property (iv-6) means that the material exhibits excellent transmittance in the red band and excellent light shielding in the near-infrared region beyond 770 nm. Optical property (iv-6) is preferably in the range of 725 to 765 nm, more preferably in the range of 730 to 760 nm.

[0036] Optical properties (iv-7) to (iv-8) specify the acceptable range of light loss in the near-infrared region. T 780-850(0deg)MAX The amount is preferably 4-9%, more preferably 4-8%. T 900-980(40deg)MAX The amount is preferably 1-4.5%, more preferably 1-4%.

[0037] As shown in the optical properties (iv-2) to (iv-5) of the dielectric multilayer film in the present invention, ripple generation in the visible light region is suppressed even at a high incidence angle of 40 degrees. On the other hand, as shown in the optical characteristics (iv-7) to (iv-8) above, light loss may occur at incident angles of 0 and 40 degrees, and in the near-infrared wavelength region beyond 780 nm. Since this wavelength region is covered by the absorption of the NIR dye in the resin film, which will be described later, the optical filter as a whole is shielded even if light loss occurs.

[0038] The optical filter of the present invention, by combining such dielectric multilayer film with a resin film described later, has high visible light transmittance as shown in optical characteristic (i-7), high near-infrared light shielding as shown in optical characteristic (i-10), suppresses ripple even at high incidence angles as shown in optical characteristics (i-1) to (i-2) and (i-4) to (i-6), and suppresses changes in shielding performance at high incidence angles of near-infrared light as shown in optical characteristic (i-8).

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

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

[0041] The NIR reflective layer is composed of 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 stacked. The high refractive index film preferably has a refractive index of 1.6 or higher, and more preferably 2.2 to 2.5. Examples of materials for the high refractive index film include Ta2O5, TiO2, and Nb2O5. Of these, TiO2 is preferred in terms of film formation properties, reproducibility in refractive index, stability, etc.

[0042] On the other hand, the low refractive index film preferably has a refractive index of less than 1.6, and more preferably 1.45 or more and less than 1.55. Examples of materials for the low refractive index film are SiO2, SiO2, and SiO2. x N y These are some examples. SiO2 is preferred in terms of reproducibility, stability, and cost-effectiveness in film formation.

[0043] To create a multilayer film in which ripple is suppressed even at high incidence angles, but in which light loss can occur in the near-infrared wavelength region above 780 nm, one possible solution is to reduce the number of layers in the multilayer film.

[0044] The NIR reflective layer preferably has a total number of layers of dielectric multilayer films constituting the reflective layer, more preferably 25 layers or more, and even more preferably 30 layers or more, from the viewpoint of light shielding in the near-infrared wavelength region. However, as the total number of layers increases, ripples and warping may occur, and the film thickness may increase, so 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. Furthermore, the thickness of the reflective layer is preferably 2 to 10 μm overall from the viewpoint of reducing the warping of the optical filter.

[0045] Furthermore, for the formation of dielectric multilayer films, vacuum deposition processes such as CVD, sputtering, and vacuum evaporation, as well as wet deposition processes such as spraying and dipping, can be used.

[0046] The NIR reflective layer may provide predetermined optical properties with a single layer (a group of dielectric multilayer films) or with two layers. If there are two or more layers, each reflective layer may have the same or different configuration. When there are two or more reflective layers, they are usually composed of multiple reflective layers with different reflection bands. When two reflective layers are provided, one may be a near-infrared reflective layer that shields light in the short-wavelength band of the near-infrared region, and the other may be a near-infrared / near-ultraviolet reflective layer that shields light in both the long-wavelength band of the near-infrared region and the near-ultraviolet region.

[0047] Examples of anti-reflective layers include dielectric multilayer films, intermediate refractive index media, and moth-eye structures with gradually changing refractive indices. Among these, dielectric multilayer films are preferred from the viewpoint of optical efficiency and productivity. The anti-reflective layer is obtained by alternately stacking dielectric multilayer films, similar to the reflective layer.

[0048] <Base material> In the optical filter of the present invention, the substrate has a resin film containing the NIR dye (IR) and resin described later.

[0049] <Optical properties of resin films> The resin film preferably satisfies all of the following optical properties (ii-1) to (ii-6). (ii-1) Average internal transmittance T at wavelengths of 450-580 nm 450-580AVE over 88% (ii-2) At wavelengths of 600-700 nm, the wavelength at which the internal transmittance is 20% is in the range of 640-690 nm. (ii-3) Internal transmittance T at a wavelength of 700 nm 700 less than 1% (ii-4) Internal transmittance T at a wavelength of 750 nm 750 less than 10% (ii-5) Internal transmittance T at a wavelength of 800 nm 800 less than 20% (ii-6) Internal transmittance T at a wavelength of 950 nm 950 60% to 95%

[0050] Satisfying optical property (ii-1) means that the transmittance in the visible light region is high. T 450-580AVE This is preferably 89% or more, and more preferably 90% or more.

[0051] By satisfying optical properties (ii-2), it means that the oblique incidence shift of dielectric multilayer films, which exhibit excellent transmittance in the red band and excellent light shielding in the near-infrared region beyond 700 nm, can be compensated for. The optical properties (ii-2) are preferably in the range of 645 to 685 nm, more preferably 650 to 680 nm.

[0052] By satisfying optical properties (ii-3) to (ii-5), it means that wavelength ranges where light leakage is likely to occur in dielectric multilayer films can be blocked by absorption. T 700 It is preferably 0.9% or less. T 750 The percentage is preferably 9.5% or less, and more preferably 9% or less. T 800 The percentage is preferably 18% or less, and more preferably 16% or less.

[0053] Optical properties (ii-6) specify the range of transmittance that is permissible in the long-wavelength region. T 950 is preferably 60% or more and 92.5% or less, more preferably 60% or more and 90% or less.

[0054] <NIR dye The NIR dye (IR) is a NIR dye having a maximum absorption wavelength in the range of 680 to 1000 nm in dichloromethane. By containing such a dye, near-infrared light can be effectively cut.

[0055] The dye (IR) preferably satisfies the following characteristic (iii-1) in the spectral internal transmittance curve measured by dissolving the dye (IR) in the resin so that the internal transmittance at the maximum absorption wavelength in the resin constituting the resin film becomes 10%. (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)

[0056] The dye (IR) has a maximum absorption wavelength in the near-infrared light region. However, as the maximum absorption wavelength is larger, the dye is more likely to absorb visible light, so 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 value of the visible light transmittance. Therefore, a dye (IR) that satisfies the characteristic (iii-1) means that the visible light transmittance is sufficiently high. The characteristic (iii-1) is more preferably E> 101.5-(D / 100).

[0057] The NIR dye (IR) may consist of one kind of compound or may contain two or more kinds of compounds. From the viewpoint of easily satisfying the above optical characteristics (ii-3) to (ii-6) of the resin film that widely absorbs light in the wavelength range of 700 to 1000 nm, it preferably contains three or more kinds of compounds having a maximum absorption wavelength in the range of 680 to 1000 nm in dichloromethane. Particularly, it is more preferable to contain at least one kind of compound selected from each of the following compounds (A) to (C). Compound (A): A compound having a maximum absorption wavelength in the range of 690 nm or more and less than 735 nm in dichloromethane Compound (B): A compound having a maximum absorption wavelength in dichloromethane between 735 nm and 835 nm. Compound (C): A compound having a maximum absorption wavelength between 900 nm and 1000 nm in dichloromethane.

[0058] Furthermore, the maximum difference between the maximum absorption wavelength of compound (A) and the maximum absorption wavelength of compound (B) is preferably 40 nm or more, more preferably 50 nm or more. This allows for efficient absorption and shielding of wavelengths where light leakage is likely to occur in the dielectric multilayer film.

[0059] From the viewpoint of visible light transmittance, solubility in resin, and durability, it is preferable that compound (A) is selected from one or more squarylium compounds and cyanine compounds, compound (B) is selected from one or more squarylium compounds and cyanine compounds, and compound (C) is selected from one or more squarylium compounds, cyanine compounds, and imonium compounds.

[0060] <Squiririum compounds> The squarylium compound is preferably a compound represented by formula (I) below, a compound represented by formula (II) described later, or a compound represented by formula (V) described later. Furthermore, if two or more identical symbols exist in a squarylium compound, these symbols may be identical or different. The same applies to cyanine compounds.

[0061] <Squallium compound (I)>

[0062] [ka]

[0063] However, the symbols in the above formula are as follows: R 24 and R 26Each of these independently consists of a hydrogen atom, a halogen atom, a hydroxyl group, a C1-C20 alkyl or alkoxy group, a C1-C10 acyloxy group, a C6-C11 aryl group, a C7-C18 alaryl group which may have substituents and may have oxygen atoms between carbon atoms, and -NR 27 R 28 (R 27 and R 28 These are, independently, a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, and -C(=O)-R 29 (R 29 (This may include hydrogen atoms, halogen atoms, hydroxyl groups, hydrocarbon groups having 1 to 25 carbon atoms that may have substituents, unsaturated bonds between carbon atoms, oxygen atoms, or saturated or unsaturated ring structures), -NHR 30 , or -SO2-R 30 (R 30 (R) represents a hydrocarbon group having 1 to 25 carbon atoms, in which each hydrogen atom may be substituted with a halogen atom, hydroxyl group, carboxyl group, sulfo group, or cyano group, and which may contain unsaturated bonds, oxygen atoms, or saturated or unsaturated ring structures between carbon atoms. ) or a group represented by the following formula (S) (R) 41 , R 42 k independently represents a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 10 carbon atoms. k is 2 or 3.

[0064] [ka]

[0065] R 21 and R 22 , R 22 and R 25 , and R 21 and R 23 These may be linked together to form heterocycles A, B, and C, respectively, with nitrogen atoms, each having a membership of 5 or 6. R when a heteroalgebra A is formed 21 and R 22is, as the divalent group -Q- formed by combining these, a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an alkylene group optionally substituted with an acyloxy group having 1 to 10 carbon atoms which may have a substituent, or an alkyleneoxy group. R when heterocyclic ring B is formed 22 and R 25 and R when heterocyclic ring C is formed 21 and R 23 are, as the divalent group -X- formed by combining these respectively 1 -Y- 1 - and -X- 2 -Y- 2 -(where the side bonded to nitrogen is X 1 and X 2 ) as, X 1 and X 2 are each a group represented by the following formula (1x) or (2x), and Y 1 and Y 2 are each a group represented by any one selected from the following formulas (1y) to (5y). When X 1 and X 2 are each a group represented by the following formula (2x), Y 1 and Y 2 may each be a single bond, and in that case, it may have an oxygen atom between carbon atoms.

[0066]

Chemical formula

[0067] In formula (1x), the four Zs are each independently a hydrogen atom, a hydroxyl group, an alkyl group or an alkoxy group having 1 to 6 carbon atoms, or -NR 38 R 39 (R 38 and R 39 each independently represent a hydrogen atom or an alkyl group having 1 to 20 carbon atoms). R 31 ~R 36 are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms, R 37This represents an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms. R 27 , R 28 , R 29 , R 31 ~R 37 , R when it does not form a heteroalgebra 21 ~R 23 , and R 25 These may bond with any of the others to form a five-membered ring or a six-membered ring. 31 and R 36 , R 31 and R 37 They may be directly joined. When R does not form a heteroalgebra, 21 , R 22 , R 23 and R 25 Each of these independently represents a hydrogen atom, a halogen atom, a hydroxyl group, a C1-C20 alkyl or alkoxy group, a C1-C10 acyloxy group, a C6-C11 aryl group, or a C7-C18 alaryl group which may have substituents or oxygen atoms between carbon atoms.

[0068] Examples of compound (I) include compounds represented by any of formulas (I-1) to (I-3), and from the viewpoint of solubility in the resin, heat resistance and light resistance in the resin, and visible light transmittance of the resin layer containing it, the compound represented by formula (I-1) is particularly preferred.

[0069] [ka]

[0070] The symbols in formulas (I-1) to (I-3) are the same as those specified for the same symbols in formula (I), and the preferred embodiments are also the same.

[0071] In compound (I-1), X 1 As for the base, (2x) is preferred, Y 1 A single bond or group (1y) is preferred. In this case, R 31 ~R36 Preferably, it is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom or a methyl group. 1 -X 1 Specifically, examples include the divalent organic groups shown in formulas (11-1) to (12-3).

[0072] -C(CH3)2-CH(CH3)- …(11-1) -C(CH3)2-CH2- …(11-2) -C(CH3)2-CH(C2H5)- …(11-3) -C(CH3)2-C(CH3)(nC3H7)- …(11-4) -C(CH3)2-CH2-CH2- …(12-1) -C(CH3)2-CH2-CH(CH3)- …(12-2) -C(CH3)2-CH(CH3)-CH2- …(12-3)

[0073] Furthermore, in compound (I-1), R 21 From the viewpoint of solubility, heat resistance, and the steepness of the change near the boundary between the visible and near-infrared regions in the spectral transmittance curve, the group represented by formula (4-1) or (4-2) is independently more preferred.

[0074] [ka]

[0075] In equations (4-1) and (4-2), R 71 ~R 75 This independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms.

[0076] In compound (I-1), R 24 -NR 27 R 28 Preferably. -NR 27 R 28 From the perspective of solubility in resins and coating solvents, -NH-C(=O)-R 29 or -NH-SO2-R30 It is preferable.

[0077] In compound (I-1), R 24 -NH-C(=O)-R 29 The compound is shown in formula (I-11).

[0078] [ka]

[0079] R 23 and R 26 These are preferably, independently, a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 6 carbon atoms, with a hydrogen atom being more preferred in any case.

[0080] R 29 Preferred substituents include C1-C20 alkyl groups which may have substituents, C6-C10 aryl groups which may have substituents, or C7-C18 alaryl groups which may have substituents and may have oxygen atoms between carbon atoms. Examples of substituents include hydroxyl groups, carboxyl groups, sulfo groups, cyano groups, C1-C6 alkyl groups, C1-C6 fluoroalkyl groups, C1-C6 alkoxy groups, and C1-C6 acyloxy groups.

[0081] R 29 Preferably, the group is selected from linear, branched, or cyclic alkyl groups having 1 to 17 carbon atoms, phenyl groups which may be substituted with alkoxy groups having 1 to 6 carbon atoms, and alaryl groups having 7 to 18 carbon atoms which may have oxygen atoms between carbon atoms.

[0082] R 29 As an example, groups that are hydrocarbon groups having 5 to 25 carbon atoms and having at least one branch may also be used, in which one or more hydrogen atoms may be independently substituted with a hydroxyl group, a carboxyl group, a sulfo group, or a cyano group, and which may contain unsaturated bonds, oxygen atoms, or saturated or unsaturated ring structures between carbon atoms.

[0083] As the compound (I-11), more specifically, the compounds shown in the following table can be mentioned. In addition, in the compounds shown in the following table, the meanings of each symbol are the same on the left and right of the squarylium skeleton.

[0084]

Table 1

[0085] Among these, as the compound (I-11), from the viewpoints of visible light transmittance and solubility in resins, compounds (I-11-11) to (I-11-15), (I-11-26) to (I-11-30), etc. are preferable.

[0086] In the compound (I-1), R 24 being -NH-SO2-R 30 is shown in formula (I-12).

[0087]

Chemical formula

[0088] R 23 and R 26 are independently 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 in any case.

[0089] R 30 is preferably, from the viewpoint of light resistance, independently 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. Examples of the unsaturated ring structure include benzene, toluene, xylene, furan, benzofuran, etc. R 30 is more preferably, independently, an alkyl group or an alkoxy group having 1 to 12 carbon atoms which may have a branch. In addition, in each group representing R 30 , part or all of the hydrogen atoms may be substituted with a halogen atom, particularly a fluorine atom.

[0090] As the compound (I-12), more specifically, the compounds shown in the following table can be mentioned. In addition, for the compounds shown in the following table, the meanings of the respective symbols are the same on the left and right of the squarylium skeleton.

[0091] [Table 2]

[0092] As the compound (I-12), among these, from the viewpoints of the transparency in the visible light region and the solubility in resins, compounds (I-12-11) to (I-12-15), (I-12-26) to (I-12-30), etc. are preferable.

[0093] <Squarylium compound (II)>

[0094] [Chemical formula]

[0095] However, the symbols in the above formula are as follows. Ring Z is, independently of each other, a 5-membered ring or a 6-membered ring having 0 to 3 heteroatoms in the ring, and the hydrogen atoms of ring Z may be substituted. R 1 and R 2 、R 2 and R 3 、and R 1 and the carbon atoms or heteroatoms constituting ring Z may be linked to each other to form hetero rings A1, hetero ring B1, and hetero ring C1 together with a nitrogen atom, and in that case, the hydrogen atoms of hetero ring A1, hetero ring B1, and hetero ring C1 may be substituted. When no hetero ring is formed, R 1 and R 2 each independently represent a hydrogen atom, a halogen atom, or a hydrocarbon group that may contain an unsaturated bond, a heteroatom, a saturated or unsaturated ring structure between carbon atoms and may have a substituent. R 4 and when no hetero ring is formed, R 3Each of these independently represents an alkyl or alkoxy group which may contain a hydrogen atom, a halogen atom, or a heteroatom between carbon atoms, and which may have substituents.

[0096] Examples of compound (II) include compounds represented by any of formulas (II-1) to (II-3), and from the viewpoint of solubility in the resin and visible light transmittance in the resin, the compound represented by formula (II-3) is particularly preferred.

[0097] [ka]

[0098] In formula (II-1) and formula (II-2), R 1 and R 2 Each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 15 carbon atoms which may have substituents, and R 3 ~R 6 Each of these independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms, which may have substituents.

[0099] In formula (II-3), R 1 , R 4 , and R 9 ~R 12 Each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 15 carbon atoms which may have substituents, and R 7 and R 8 Each of these independently represents a hydrogen atom, a halogen atom, or a C1-C5 alkyl group which may have substituents.

[0100] R in compound (II-1) and compound (II-2) 1 and R 2 From the viewpoint of solubility in resin, visible light transmittance, etc., an alkyl group having 1 to 15 carbon atoms is preferred, and an alkyl group having 7 to 15 carbon atoms is more preferred, R 1 and R 2 At least one of them is more preferably an alkyl group having a branched chain with 7 to 15 carbon atoms, R1 and R 2 Alkyl groups having branched chains with 8 to 15 carbon atoms are particularly preferred for both.

[0101] R in compound (II-3) 1 From the viewpoint of solubility in transparent resins and visible light transmittance, alkyl groups having 1 to 15 carbon atoms are preferred, alkyl groups having 1 to 10 carbon atoms are more preferred, and ethyl groups and isopropyl groups are particularly preferred.

[0102] R 4 From the viewpoint of visible light transmittance and ease of synthesis, hydrogen atoms and halogen atoms are preferred, with hydrogen atoms being particularly preferred. R 7 and R 8 The following are preferred independently: a hydrogen atom, a halogen atom, and a C1-C5 alkyl group which may be substituted with a halogen atom; a hydrogen atom, a halogen atom, and a methyl group are more preferred.

[0103] R 9 ~R 12 The following are preferred independently: a hydrogen atom, a halogen atom, and a C1-C5 alkyl group which may be substituted with a halogen atom. -CR 9 R 10 -CR 11 R 12 -Examples include the divalent organic groups represented by the following groups (13-1) to (13-5). -CH(CH3)-C(CH3)2- …(13-1) -C(CH3)2-CH(CH3)- …(13-2) -C(CH3)2-CH2- …(13-3) -C(CH3)2-CH(C2H5)- …(13-4) -CH(CH3)-C(CH3)(CH2-CH(CH3)2)-…(13-5)

[0104] More specifically, compounds (II-3) include those shown in the table below. Furthermore, in the compounds shown in the table below, the meaning of each symbol is the same on both the left and right sides of the squarylium skeleton.

[0105]

Table 3

[0106] Compounds (I) to (II) can be produced by known methods respectively. For compound (I), it can be produced by the methods described in U.S. Patent No. 5,543,086, U.S. Patent Application Publication No. 2014 / 0061505, and International Publication No. 2014 / 088063. For compound (II), it can be produced by the method described in International Publication No. 2017 / 135359.

[0107] <Cyanine compound> The cyanine compound is preferably a compound represented by the following formula (III) or formula (IV).

[0108] <Cyanine compounds (III), (IV)>

[0109]

Chemical formula

[0110] However, the symbols in the above formula are as follows. R 101 ~R 109 and R 121 ~R 131 each independently represents 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. R 110 ~R 114 and R 132 ~R 136 each independently represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 15 carbon atoms. X - represents a monovalent anion. n1 and n2 are 0 or 1. -(CH2) n1 -containing carbocyclic ring, and, -(CH2) n2The hydrogen atom bonded to the carbon ring containing - may be substituted with a halogen atom, a C1-C15 alkyl group which may have substituents, or a C5-C20 aryl group.

[0111] In the above, the alkyl group (including the alkyl group of the alkoxy group) may be linear, branched, or saturated. The aryl group is a group that is bonded via carbon atoms constituting the aromatic ring of an aromatic compound, such as a benzene ring, naphthalene ring, biphenyl, furan ring, thiophene ring, pyrrole ring, etc. Substituents in C1-C15 alkyl or alkoxy groups, or C5-C20 aryl groups, which may have substituents, include halogen atoms and C1-C10 alkoxy groups.

[0112] In equations (III) and (IV), R 101 and R 121 The alkyl group is preferably a C1-C15 alkyl group or a C5-C20 aryl group, and a branched C1-C15 alkyl group is more preferred from the viewpoint of maintaining high visible light transmittance in the resin.

[0113] In equations (III) and (IV), R 102 ~R 105 , R 108 , R 109 , R 122 ~R 127 , R 130 and R 131 Each of these is preferably an independent hydrogen atom, an alkyl or alkoxy group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms, with hydrogen atoms being more preferred from the viewpoint of obtaining high visible light transmittance.

[0114] In equations (III) and (IV), R 110 ~R 114 and R 132 ~R 136 Each of these is preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms, with hydrogen atoms being more preferred from the viewpoint of obtaining high visible light transmittance.

[0115] R 106 , R 107 , R 128 and R 129 Each of these is preferably a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms (which may include linear, cyclic, or branched alkyl groups), and more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. 106 and R 107 , R 128 and R 129 The same group is preferable.

[0116] X - As for, I - BF4 - PF6 - ClO4 - Examples include anions represented by formulas (X1) and (X2), preferably BF4 - , or PF6 - That is the case.

[0117] [ka]

[0118] In the following explanation, R in compound (III) 101 ~R 114 The portion excluding the specified part is also called the skeleton (III). The same applies to compound (IV).

[0119] In equation (III), compounds with n1 = 1 are shown in equation (III-1) below, and compounds with n1 = 0 are shown in equation (III-2) below.

[0120] [ka]

[0121] In equations (III-1) and (III-2), R 101 ~R 114 and X - This is the same as in the case of equation (III). R 115 ~R120 Each of these independently represents a hydrogen atom, a halogen atom, an alkyl or alkoxy group having 1 to 15 carbon atoms which may have substituents, or an aryl group having 5 to 20 carbon atoms. 115 ~R 120 Each of these is preferably a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms (which may include linear, cyclic, or branched alkyl groups), and more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. 115 ~R 120 It is preferable that they be the same group.

[0122] In equation (IV), compounds with n² = 1 are shown in equation (IV-1) below, and compounds with n² = 0 are shown in equation (IV-2) below.

[0123] [ka]

[0124] In equations (IV-1) and (IV-2), R 121 ~R 136 and X - This is the same as in case (IV). 137 ~R 142 Each of these independently represents a hydrogen atom, a halogen atom, an alkyl or alkoxy group having 1 to 15 carbon atoms which may have substituents, or an aryl group having 5 to 20 carbon atoms. 137 ~R 142 Each of these is preferably a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms (which may include linear, cyclic, or branched alkyl groups), and more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. 137 ~R 142 It is preferable that they be the same group.

[0125] More specifically, the compounds represented by formulas (III-1), (III-2), (IV-1), and (IV-2) are compounds in which the atoms or groups bonded to each skeleton are those shown in the table below. In all the compounds shown in the table below, R 101 ~R 109 The terms are identical on both sides of the equation. In all the compounds shown in the table below, R 121 ~R 131 The terms on both sides of the equation are identical.

[0126] R in the table below 110 -R 114 and R in the table below 132 -R 136 The symbol indicates the atom or group bonded to the central benzene ring in each formula, and "H" is written when all five are hydrogen atoms. 110 -R 114 If one of the atoms is a substituent and the others are hydrogen atoms, only the combination of the sign of the substituent and the substituent is listed. For example, "R 112 The description "-C(CH3)3" is R 112 This indicates that -C(CH3)3 and the others are hydrogen atoms. 132 -R 136 The same applies to this matter.

[0127] R in Table 4 115 -R 120 and R in Table 6 137 -R 142 R indicates the atom or group bonded to the central cyclohexane ring in formulas (III-1) and (IV-1), and is denoted as "H" if all six are hydrogen atoms. 115 -R 120 If one of the atoms is a substituent and the others are hydrogen atoms, only the combination of the sign of the substituent and the substituent is listed. 137 -R 142 The same applies to this matter.

[0128] R in Table 5 115 -R 118 and R in Table 7 137 -R 140R indicates the atom or group bonded to the central cyclopentane ring in formulas (III-2) and (IV-2), and is denoted as "H" if all four are hydrogen atoms. 115 -R 118 If one of the atoms is a substituent and the others are hydrogen atoms, only the combination of the sign of the substituent and the substituent is listed. 137 -R 140 The same applies to this matter.

[0129] The table below contains X - Although it does not show, X is present in all compounds. - is BF4 - or PF6 - That is the case.

[0130] [Table 4]

[0131] Among these, compounds (III-1-1) to (III-1-5) are preferred as compound (III-1) in terms of transmittance in the visible light range and solubility in resin.

[0132] [Table 5]

[0133] Among these, compounds (III-2-1) to (III-2-5) are preferred as compound (III-2) in terms of transmittance in the visible light range and solubility in resin.

[0134] [Table 6]

[0135] Among these, compounds (IV-1-1) to (IV-1-5) are preferred as compound (IV-1) in terms of transmittance in the visible light range and solubility in resin.

[0136] [Table 7]

[0137] Among these, compounds (IV-2-1) to (IV-2-5) are preferred as compound (IV-2) in terms of transmittance in the visible light range and solubility in resin.

[0138] Compounds (III) and (IV) have different skeletons, as described above, and consequently, their absorption maximum wavelength ranges differ. In compound (III), although it depends on the type and combination of atoms and groups bonded to the skeleton, the maximum absorption wavelength is generally in the 760-830 nm range. In compound (IV), although it depends on the type and combination of atoms and groups bonded to the skeleton, the maximum absorption wavelength is generally in the 800-900 nm range.

[0139] Furthermore, in compound (III), the maximum absorption wavelength differs depending on whether n1 of the skeleton is 1 or 0. Depending on the type and combination of atoms and groups bonded to the skeleton, when n1 is 1, the maximum absorption wavelength is generally in the wavelength range of 760-800 nm, while when n1 is 0, the maximum absorption wavelength is generally in the wavelength range of 800-830 nm.

[0140] Similarly, in compound (IV), the maximum absorption wavelength differs depending on whether n2 is 1 or 0. Depending on the type and combination of atoms and groups bonded to the skeleton (IV-1), when n2 is 1, the maximum absorption wavelength is generally in the wavelength range of 800-830 nm, while when n2 is 0, the maximum absorption wavelength is generally in the wavelength range of 830-900 nm.

[0141] Compounds (III) and (IV) can be prepared by methods described, for example, in Dyes and Pigments 73 (2007) 344-352 and J. Heterocyclic Chem, 42, 959 (2005).

[0142] <Squallium compound (V)>

[0143] [ka]

[0144] In formula (V), R 51 ~R 54 Each of these is independently a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group, an aryl group, or an alaryl group. The alkyl group, aryl group, or alaryl group may have substituents. Furthermore, alkyl groups, aryl groups, or alaryl groups may contain unsaturated bonds, oxygen atoms, ester bonds, amide bonds, or thioamide bonds between carbon atoms. Furthermore, the alkyl group, aryl group, or alaryl group may have an oxygen atom, ester bond, amide bond, or 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 These rings may be linked to each other to form a monocyclic ring or a polycyclic ring formed by the fusion of 2 to 4 rings, in which case the hydrogen atoms bonded to the ring may be substituted with substituents.

[0145] Examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms. Fluorine atoms and chlorine atoms are preferred.

[0146] R 51 ~R 54 If the alkyl group is present, the number of carbon atoms is preferably 1 to 20, more preferably 1 to 15, and even more preferably 1 to 12. R 51 ~R 54 If the group is an aryl group, the number of carbon atoms is preferably 4 to 20, more preferably 4 to 17, and even more preferably 4 to 14. R 51 ~R 54 If the group is an alkyl group, the number of carbon atoms is preferably 5 to 20, more preferably 5 to 18, and even more preferably 5 to 15. R51 ~R 54 If the substituent has a substituent, the above carbon number includes the carbon number of the substituent.

[0147] R 51 ~R 54 Substituents in include halogen atoms, hydroxyl groups, carboxyl groups, sulfo groups, cyano groups, amino groups, N-substituted amino groups, nitro groups, alkoxycarbonyl groups, carbamoyl groups, N-substituted carbamoyl groups, imide groups, and alkoxy groups having 1 to 10 carbon atoms. 51 ~R 54 If the group is an aryl group or an aryl group, the substituent is a group that substitutes for a hydrogen atom bonded to the aromatic ring or a hydrogen atom of the alkyl group they possess, and in addition to the substituent, it may also include an aryl group.

[0148] R 51 and R 52 , R 52 and R 53 , and, R 53 and R 54 These rings may be linked to each other to form a monocyclic ring or a polycyclic ring formed by the fusion of 2 to 4 rings, in which case the hydrogen atoms bonded to the ring may be substituted with substituents.

[0149] R 52 and R 53 When linked, the squarylium compound (V) contains a structure in which at least three rings are fused together, with a ring formed between the two thiophene rings. 52 and R 53 The hydrogen atoms bonded to the ring formed by the linking of these atoms may be substituted with substituents. R 52 and R 53 As substituents that substitute for hydrogen atoms bonded to the linked ring, R 51 ~R 54 Examples include groups similar to the substituents in and phenyl groups which may have substituents. R 51 ~R 54 Examples of substituents similar to those in the above include groups similar to those in the above.

[0150] R55 and R 56 Each of these is independently an alkyl group that may have substituents, an unsaturated bond between carbon atoms, an oxygen atom or a nitrogen atom, or an alaryl group. 55 and R 56 These atoms may be linked together to form a cycloheteroracic ring with 5 to 10 members together with the nitrogen atom, in which case the hydrogen atoms bonded to the ring may be substituted with substituents.

[0151] R 55 and R 56 As substituents in this case, R 51 ~R 54 Examples of substituents similar to those in R include: 55 and R 56 If the alkyl group is an aryl group, the alkyl group it possesses may be further substituted with an aryl group.

[0152] R 55 and R 56 However, in the case of alkyl groups, the number of carbon atoms is preferably 1 to 20, more preferably 1 to 12, and even more preferably 1 to 10. 55 and R 56 From the viewpoint of visible light transmittance and solubility in resins and solvents, linear, branched, or cyclic alkyl groups having 3 to 20 carbon atoms, which may contain oxygen atoms between carbon atoms, are preferred. The number of carbon atoms in the alkyl group is more preferably 3 to 12 for linear groups, more preferably 3 to 10 for branched groups, and more preferably 5 to 10 for cyclic groups. 15 and R 16 If the substituent has a substituent, the above carbon number includes the carbon number of the substituent. R 55 and R 56 For example, a group selected from groups (1a) to (15a) is more preferable, and group (1a) is particularly preferred.

[0153] [ka]

[0154] R 55 and R 56 These atoms may be linked together with a nitrogen atom to form a cycloheterocycle with a membership of 5 to 10. The cycloheterocycle may contain an oxygen atom in addition to the nitrogen atom as a ring constituent element. The membership of the cycloheterocycle is preferably 5 or 6, and particularly preferably 5. When a hydrogen atom bonded to the cycloheterocycle is substituted, examples of substituents that substitute for the hydrogen atom include a halogen atom, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 6 to 20 carbon atoms, or an alaryl group having 7 to 20 carbon atoms.

[0155] R 55 and R 56 When a divalent group to which is bonded is denoted as -Q-, the following groups (11) to (14) can be specifically listed as -Q-.

[0156] -(CH2)4- …(11) -(CH2)5- …(12) -C(CH3)2(CH2)2C(CH3)2- …(13) -C(CH3)2(CH2)3C(CH3)2- …(14)

[0157] As the squarylium compound (V), for example, the compound represented by formula (V-1) or the compound represented by formula (V-2) below is preferred. In the squarylium compound (V), R 52 and R 53 It is a compound formed by the linkage of R to form a cyclopentadithiophene ring. Squaryllium compound (V-2) is a compound in which R 52 and R 53 This compound contains structures in which two thiophene rings are bonded together, rather than being linked.

[0158] [ka]

[0159] R 51 , R 54 , R55 and R 56 R in equation (V) 51 , R 54 , R 55 and R 56 The same applies to preferred embodiments as well. R 52b and R 53b Except for the fact that they do not connect to each other to form a ring, the R in equation (V) 52 and R 53 The same applies to preferred embodiments as well.

[0160] R 52a and R 53a From the viewpoint of visible light transmittance, light resistance, and solubility in resins and solvents, linear, branched, or cyclic alkyl groups having 1 to 20 carbon atoms, which may contain oxygen atoms between carbon atoms, are preferred. The number of carbon atoms in the alkyl group is more preferably 1 to 12 for linear groups, more preferably 3 to 10 for branched groups, and more preferably 5 to 10 for cyclic groups. 52a and R 53a For example, a group selected from groups (1a) to (15a) is more preferable, and group (1a), group (3a), or group (9a) is particularly preferable.

[0161] R 52a and R 53a From the viewpoint of transmittance in the visible light range and lightfastness, a phenyl group which may have 1 to 5 substituents, a naphthyl group which may have 1 to 7 substituents, or an alkyl group having 1 to 10 carbon atoms is preferred. Examples of substituents for the phenyl group and naphthyl group include an alkyl group or alkoxy group having 1 to 12 carbon atoms which may contain an unsaturated bond or oxygen atom between carbon atoms, or an alkylamino group (alkyl group having 1 to 12 carbon atoms), with methyl group, tert-butyl group, dimethylamino group, methoxy group, etc., being particularly preferred. The phenyl group and naphthyl group are preferably unsubstituted or substituted with 1 to 3 hydrogen atoms.

[0162] Specific examples of phenyl groups that may have 1 to 5 substituents include groups (P1) to (P9).

[0163] [ka]

[0164] Examples of naphthyl groups that may have 1 to 7 substituents include groups (N1) to (N9).

[0165] [ka]

[0166] More specifically, compound (V-1) includes the compounds shown in the table below. Furthermore, in the compounds shown in the table below, the meaning of each symbol is the same on both the left and right sides of the squarylium skeleton.

[0167] [Table 8]

[0168] Among these, compounds (V-1-5) and (V-1-12) are preferred as compound (V-1) in terms of transmittance in the visible light range and solubility in resin.

[0169] More specifically, compounds (V-2) include those listed in the table below. Furthermore, in the compounds listed in the table below, the meaning of each symbol is the same on both the left and right sides of the squarylium skeleton.

[0170] [Table 9]

[0171] Squallium compound (V) can be prepared by known methods, for example, by the method described in International Publication No. 2019 / 230660.

[0172] <Imonium compounds> The imonium compound is preferably a compound represented by the following formula (A1) or formula (A2).

[0173] [ka]

[0174] The symbols in formulas (A1) and (A2) are as follows: R 201 ~R 206 and R 221 ~R 226 Each of these is independently a hydrogen atom, a halogen atom, a sulfo group, a hydroxyl group, a cyano group, a nitro group, a carboxyl group, a phosphate group, a C1-C20 alkyl or alkoxy group which may have an oxygen atom between carbon atoms and may be substituted, or a C6-C14 aryl group which may be substituted, a C7-C14 aralkyl group which may be substituted, or a C3-C14 heterocyclic group which may be substituted. However, groups in which a substituted or unsubstituted amino group is bonded to a phenyl group are excluded. Furthermore, R 201 ~R 206 and R 221 ~R 226 In this configuration, two groups bonded to the same nitrogen atom may bond to each other to form a heterocycle with 3 to 8 members together with the nitrogen atom, and the hydrogen atom bonded to the ring may be substituted with an alkyl group having 1 to 12 carbon atoms.

[0175] R 207 ~R 218 and R 227 ~R 238 Each of these is independently a hydrogen atom, a halogen atom, an optionally substituted amino group, amide group, cyano group, nitro group, carboxyl group, or an optionally substituted C1-C12 alkyl or alkoxy group. 207 ~R 218 and R 227 ~R 238In this configuration, two adjacent groups may bond to each other to form a ring with 3 to 8 carbon atoms together with the two carbon atoms of the phenyl group, and the hydrogen atoms bonded to this ring may be substituted with alkyl groups having 1 to 12 carbon atoms.

[0176] R 201 ~R 206 and R 221 ~R 226 In this context, substituents on optionally substituted C1-C20 alkyl or alkoxy groups, optionally substituted C6-C14 aryl groups, C7-C14 aralkyl groups, or C3-C14 heterocyclic groups include halogen atoms, hydroxyl groups, optionally substituted C1-C6 alkyl groups, carboxyl groups, sulfo groups, cyano groups, and C1-C6 acyloxy groups.

[0177] R when no ring is formed 207 ~R 218 and R 227 ~R 238 Each of these is preferably a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 12 carbon atoms. The alkyl or alkoxy group preferably has 1 to 6 carbon atoms, and more preferably 1 to 4 carbon atoms.

[0178] R 207 ~R 218 and R 227 ~R 238 In this compound, the ring formed by the bonding of two adjacent groups together with the two carbon atoms of the phenyl group may be an alicyclic ring, an aromatic ring, or a heterocyclic ring. Examples of heteroatoms include nitrogen, oxygen, and sulfur atoms.

[0179] R 207 ~R 218 and R 227 ~R 238 In this, there are a total of 6 combinations of two adjacent groups bonding together, with 2 pairs for each of the three phenyl groups bonded to the central nitrogen atom in formulas (A1) and (A2). Specifically, in formula (A1), R207 and R 208 , R 209 and R 210 , R 211 and R 212 , R 213 and R 214 , R 215 and R 216 , R 217 and R 218 These are the 6 pairs. In equation (A2), 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 , R 237 and R 238 These are the 6 pairs.

[0180] R in equation (A1) 207 ~R 218 and R of formula (A2) 227 ~R 238 In this configuration, the number of pairs of adjacent groups bonded together may be one, two or more, and up to six pairs may be bonded together. It is preferable that three pairs of bonds, one for each of the three phenyl groups, are formed.

[0181] Specifically, examples of divalent groups formed by the bonding of two adjacent groups include alkylene groups having 1 to 6 carbon atoms, which may contain 1 to 2 nitrogen atoms as heteroatoms and may have unsaturated bonds between atoms. More specifically, the following groups (X-1) to (X-4) are examples. Note that the hydrogen atoms in these divalent groups may be substituted with alkyl groups having 1 to 12 carbon atoms.

[0182] -(CH2) n -(n is an integer from 1 to 6) ... (X-1) -CH=CH-CH=CH- …(X-2) -CH2-CH=CH- …(X-3) -N=CH-NH- …(X-4)

[0183] R207 ~R 218 and R 227 ~R 238 Each of these is preferably a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 12 carbon atoms, with hydrogen atoms or alkyl or alkoxy groups having 1 to 12 carbon atoms being preferred. The alkyl or alkoxy group preferably has 1 to 6 carbon atoms, and more preferably 1 to 4 carbon atoms.

[0184] 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 , R 224 and R 234 , R 225 and R 235 , R 226 and R 238 These atoms may bond to each other to form a heterocycle of 4 to 8 members with the nitrogen atom bonded to the phenyl group and the two carbon atoms of the phenyl group, and the hydrogen atoms bonded to the ring may be substituted with alkyl groups having 1 to 12 carbon atoms. Xa - and Xb - Each of these independently represents a monovalent anion.

[0185] In the above, the alkyl group may be linear, branched, cyclic, or a combination of these structures. The same applies to alkyl groups when an aryl group has an alkyl group, and to alkyl groups of aralkyl groups. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms, with fluorine and chlorine atoms being preferred.

[0186] In the above, an aryl group refers to a group that is bonded via a carbon atom constituting an aromatic ring (but without heteroatoms) of an aromatic compound, such as a benzene ring, naphthalene ring, or biphenyl ring. The aryl group includes structures in which a hydrogen atom bonded to a ring constituent atom other than the carbon atom contributing to the bond is substituted with an alkyl group, such as a tolyl group or a xylyl group.

[0187] In the above, an aralkyl group refers to a group in which an alkyl group is bonded to an aromatic ring (but does not contain heteroatoms), and the bond is formed via the carbon atoms constituting the alkyl group. The aralkyl group includes a structure in which hydrogen atoms bonded to ring constituent atoms other than the atom to which the alkyl group contributing to the bond is bonded are substituted with alkyl groups.

[0188] In the above, a heterocyclic group is a group that is bonded via atoms constituting an alicyclic or aromatic ring, where the atoms constituting the ring consist of carbon atoms and atoms other than carbon atoms. The heterocyclic group includes a structure in which hydrogen atoms bonded to ring constituent atoms other than the atoms contributing to the bond are alkyl substituted. Examples of atoms other than carbon atoms in the heterocyclic group include oxygen atoms, nitrogen atoms, or sulfur atoms, and the number of such atoms is preferably 1 to 2.

[0189] Xa - and Xb - As for each, independently, Cl - , Br - , I - F - ClO4 - BF4 - PF6 - SbF6 - CF3SO3 - CH3C6H4SO3 - , N[SO2R f ]2 - , C[SO2R f ]3 - These are some examples.

[0190] Here, R fR 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 organic solvents described later are good. f Examples include perfluoroalkyl groups such as -CF3, -C2F5, -C3F7, and -C4F9, as well as -C2F4H, -C3F6H, and -C2F8H.

[0191] From the viewpoint of moisture resistance, the above fluoroalkyl group is preferably a perfluoroalkyl group, and more preferably a trifluoromethyl group.

[0192] Xa - and Xb - As for each, independently, - BF 4- SbF6 - PF6 - ClO4 - , N[SO2CF3]2 - , C[SO2CF3]3 - These are preferred, and SbF6 is preferred because it shows a small difference in optical properties between the dichloromethane solution and the resin. - PF6 - and N[SO2CF3]2 - SbF6 is more preferable. - , N[SO2CF3]2 - This is particularly preferable. Also, from the viewpoint of light durability, BF 4- PF6 - , N[SO2CF3]2 - It is preferable.

[0193] The content of 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, per 100 parts by mass of resin. When two or more compounds are combined, the above content is the sum of the individual compounds. Furthermore, when the NIR dye (IR) contains compounds (A) to (C), the content of compound (A) is preferably 0.1 to 5 parts by mass per 100 parts by mass of resin, the content of compound (B) is preferably 0.1 to 5 parts by mass, and the content of compound (C) is preferably 0.1 to 5 parts by mass.

[0194] <Other pigments> The resin film may contain other dyes besides NIR dyes, such as UV dyes. UV dyes include, specifically, oxazole, merocyanine, cyanine, naphthalimide, oxadiazole, oxazine, oxazolidine, naphthalic acid, styryl, anthracene, cyclic carbonyl, and triazole dyes. UV dyes may be used individually or in combination of two or more types.

[0195] <Base material composition> The substrate in this filter may have a single-layer or multi-layer structure. Furthermore, the material of the substrate is not particularly limited; it may be an organic or inorganic material as long as it is a transparent material that transmits visible light in the 400-700 nm range. When the substrate has a single-layer structure, a resin substrate consisting of a resin film containing a resin and an NIR dye (IR) is preferred. When the substrate has a multilayer structure, a composite substrate is preferred in which a resin film containing an NIR dye (IR) is laminated on at least one main surface of the support. In this case, the support is preferably made of a transparent resin or a transparent inorganic material.

[0196] The resin is not limited to transparent resins, and one or more transparent resins selected from polyester resin, acrylic resin, epoxy resin, ene-thiol resin, polycarbonate resin, polyether resin, polyarylate resin, polysulfone resin, polyethersulfone resin, poly-paraphenylene resin, polyarylene ether phosphine oxide resin, polyamide resin, polyimide resin, polyamide-imide resin, polyolefin resin, cyclic olefin resin, polyurethane resin, and polystyrene resin can be used. These resins may be used individually or in mixtures of two or more. From the viewpoint of the optical properties of the resin film, glass transition temperature (Tg), and adhesion, one or more resins selected from polyimide resin, polycarbonate resin, polyester resin, and acrylic resin are preferred.

[0197] When multiple compounds are used as NIR dyes (IR) or other dyes, they may be contained in the same resin film, or they may each be contained in separate resin films.

[0198] Glass and crystalline materials are preferred as transparent inorganic materials. Examples of glass that can be used as a support include phthalate glass, phosphate glass, and other absorption-type glass containing copper ions (near-infrared absorbing glass), soda-lime glass, borosilicate glass, alkali-free glass, and quartz glass. As for the glass, phosphate-based glass and phthalate-based glass are preferred from the viewpoint of being able to absorb infrared light (especially 900-1200 nm). Note that "phosphate-based glass" also includes silicate glass in which part of the glass skeleton is composed of SiO2.

[0199] As the glass, chemically strengthened glass may be used, obtained by ion exchange at a temperature below the glass transition temperature, in which alkali metal ions with small ionic radii (e.g., Li ions, Na ions) present on the main surface of the glass plate are replaced with alkali ions with larger ionic radii (e.g., Na ions or K ions for Li ions, and K ions for Na ions).

[0200] Examples of crystalline materials that can be used as supports include birefringent crystals such as quartz, lithium niobate, and sapphire.

[0201] As a support material, inorganic materials are preferred, particularly glass and sapphire, from the viewpoint of shape stability related to long-term reliability such as optical properties and mechanical properties, as well as handling during filter manufacturing.

[0202] The resin film can be formed by preparing a coating solution by dissolving or dispersing a dye (IR), a resin or resin raw material component, and other components as needed in a solvent, coating this solution onto a support, drying it, and further curing it as needed. The support may be the support included in this filter, or it may be a releaseable support used only when forming the resin film. The solvent may be any dispersion medium or solvent that can stably disperse or dissolve the components.

[0203] Furthermore, the coating solution may contain a surfactant to improve voids caused by minute bubbles, indentations caused by the adhesion of foreign matter, and repulsion during the drying process. In addition, methods such as immersion coating, cast coating, or spin coating can be used for applying the coating solution. After applying the above coating solution to the support, a resin film is formed by drying. Furthermore, if the coating solution contains raw material components of a transparent resin, a curing treatment such as thermosetting or photocuring is performed.

[0204] Furthermore, the resin film can also be manufactured in film form by extrusion molding. If the substrate is a single-layer structure (resin substrate) consisting of a resin film containing a dye (IR), the resin film may be used as the substrate as is. If the substrate is a multi-layer structure (composite substrate) having a support and a resin film containing a dye (IR) laminated on at least one main surface of the support, the substrate can be manufactured by laminating this film onto the support and integrating it by thermocompression bonding or the like.

[0205] The resin film may be present as one layer within the optical filter, or as two or more layers. If there are two or more layers, each layer may have the same or different configuration.

[0206] The thickness of the resin film is preferably 20 to 150 μm when the substrate is a single-layer structure (resin substrate) consisting of a resin film containing a dye (IR). When the substrate is a multilayer structure (composite substrate) 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 preferably 0.3 to 20 μm. Furthermore, if the optical filter has two or more resin films, it is preferable that the total thickness of each resin film is within the above range.

[0207] The shape of the substrate is not particularly limited and may be in the form of a block, plate, or film. Furthermore, the thickness of the substrate is preferably 300 μm or less from the viewpoint of reducing warping during dielectric multilayer film formation and reducing the height of optical elements. When the substrate is a resin substrate consisting of a resin film, it is preferably 50 to 300 μm, and when the substrate is a composite substrate comprising a support and a resin film, it is preferably 50 to 300 μm.

[0208] This filter may also include other components, such as a component (layer) that provides absorption by inorganic nanoparticles that control the transmission and absorption of light in a specific wavelength range. Specific examples of inorganic nanoparticles include ITO (Indium Tin Oxides), ATO (Antimony-doped Tin Oxides), cesium tungstate, and lanthanum boride. ITO nanoparticles and cesium tungstate nanoparticles have high transmittance of visible light and light absorption over a wide range in the infrared wavelength region exceeding 1200 nm, and can therefore be used when shielding against such infrared light is required. [Examples]

[0209] Next, the present invention will be described in more detail with reference to examples. A UV-Vis spectrophotometer (Hitachi High-Technologies Corporation, UH-4150 model) was used to measure each optical characteristic. In addition, the optical properties when the incident angle is not specifically specified are the values measured at an incident angle of 0 degrees (the direction perpendicular to the main surface of the optical filter).

[0210] The dyes used in each example are as follows. Compound 1 (squarylium compound): Synthesized based on the specification of US Patent Application Publication No. 2014 / 0061505 and International Publication No. 2014 / 088063. Compound 2 (phthalocyanine compound): Synthesized based on the specification of Patent No. 4081149. Compound 3 (squarylium compound): Synthesized based on International Publication No. 2017 / 135359. Compounds 4 to 6 (cyanine compounds): Synthesized based on Dyes and pigments 73(2007) 344 - 352. Compound 7 (squarylium compound): Synthesized based on International Publication No. 2019 / 230660. Compound 8 (diimonium compound): Synthesized based on the specification of JP-A No. 2014 - 25016.

[0211] [Chemical formula]

[0212] [Chemical formula]

[0213] <Optical properties of IR dyes> Polyimide resin (C - 3G30G manufactured by Mitsubishi Gas Chemical) was dissolved in an organic solvent (cyclohexanone:γ - butyrolactone = 1:1 mass ratio) at a concentration of 8.5 mass%. To the solution of the polyimide resin prepared above, each dye compound was added so that it became 6 mass parts per 100 mass parts of the resin, and it was stirred for 2 hours while heating to 50°C. The dye - containing resin solution was applied to a glass substrate (alkali glass, D263 manufactured by Schott), and dried to obtain a resin film (coated film) with a film thickness of 1 μm. Using the spectral transmittance curve and spectral reflectance curve of this resin-coated glass plate, the spectral internal transmittance curve was calculated and normalized so that the transmittance at the maximum absorption wavelength was 10%. The optical properties are shown in the table below.

[0214] [Table 10]

[0215] <Examples 1-1 to 1-5: Optical properties of resin films> Polyimide resin (C-3G30G, manufactured by Mitsubishi Gas Chemical Co., Ltd.) was dissolved in an organic solvent (cyclohexanone:γ-butyrolactone = 1:1 mass ratio) at a concentration of 8.5% by mass. To the polyimide resin solution prepared above, each compound was added in the amounts (parts by mass) shown in the table below per 100 parts by mass of 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 (alkali glass, Schott D263) and dried to obtain a resin film (coated film) with a thickness of 2 μm. For the obtained resin film, transmission spectroscopy at 0 degrees of incidence and reflection spectroscopy at 5 degrees of incidence were measured in the wavelength range of 350 nm to 1200 nm. The transmittance is expressed as the internal transmittance using the following formula. Internal transmittance = Measured transmittance / (100 - reflectance) * 100 The optical properties are shown in the table below. Examples 1-1 to 1-5 are for reference only.

[0216] [Table 11]

[0217] Examples 1-1 to 1-3 have high visible light transmittance because they contain only the amount of dye necessary to absorb the near-infrared light region where light leakage can occur in multilayer films. Examples 1-4 contain insufficient dyes, and therefore fail to fully absorb the near-infrared light region, where light loss can occur in multilayer films. Examples 1-5 show a broad absorption range in the near-infrared region but low visible light transmittance. This is likely because increasing the amount of dye added broadened the absorption range, resulting in absorption of visible light as well.

[0218] <Examples 2-1 to 2-2: Optical properties of dielectric multilayer films> We designed two dielectric multilayer films: Film 1, consisting of 32 alternating layers of TiO2 and SiO2 films with a total thickness of 3.94 μm; and Film 2, consisting of 40 alternating layers with a total thickness of 4.94 μm. The optical properties of dielectric multilayer film 1 and dielectric multilayer film 2 are shown in the table below. Furthermore, the spectral transmittance curves of dielectric multilayer film 1 and dielectric multilayer film 2 are shown in Figures 5 and 6, respectively. Examples 2-1 and 2-2 are for reference only.

[0219] [Table 12]

[0220] Dielectric multilayer film 1 has low ripple, but light loss occurs beyond 780 nm. The dielectric multilayer film 2 has a large ripple, but there is almost no light loss beyond 780 nm.

[0221] <Example 3-1: Optical properties of an optical filter> A dielectric multilayer film 1 from Example 2-1 was laminated onto the main surface of a glass substrate (alkali glass, Schott D263). On the other main surface of the glass substrate, a resin film from Example 1-1 was formed by spin coating, and a dielectric multilayer film (anti-reflective film) consisting of alternating layers of SiO2 and TiO2 was deposited on the resin film by vapor deposition to fabricate an optical filter 1.

[0222] <Example 3-2: Optical properties of an optical filter> An optical filter 2 was fabricated in the same manner as in Example 3-1, except that the dielectric multilayer film 2 from Example 2-2 was stacked instead of the dielectric multilayer film 1 from Example 2-1.

[0223] <Example 3-3: Optical properties of optical filters> An optical filter 3 was fabricated in the same manner as in Example 3-1, except that the resin film of Example 1-1 was replaced with the resin film of Example 1-5.

[0224] The optical characteristics of optical filters 1 to 3 are shown in the table below. Note that Example 3-1 is an example, and Examples 3-2 and 3-3 are comparative examples.

[0225] [Table 13]

[0226] The optical filter in Example 3-1 exhibited high transmittance of visible light, low ripple at a high incident angle of 40 degrees, and simultaneously achieved light shielding in the long-wavelength region, including the near-infrared region of 750-1000 nm. The optical filter in Example 3-2 exhibited a large dependence on the incident angle of the dielectric multilayer film, and was unable to achieve low ripple at a high incident angle of 40 degrees. In Example 3-3, the optical filter exhibited a significant decrease in visible light transmittance due to excessive absorption by the dye. [Industrial applicability]

[0227] The optical filter of the present invention has excellent transmittance of visible light and good near-infrared light shielding characteristics, with suppressed changes in near-infrared light shielding performance at high incidence angles. It is useful in applications such as information acquisition devices like cameras and sensors for transport aircraft, where performance has been steadily increasing in recent years. [Explanation of symbols]

[0228] 1A, 1B, 1C, 1D... Optical filters, 10... Substrate, 11... Support, 12... Resin film, 30... Dielectric multilayer film

Claims

1. An optical filter comprising a substrate and a dielectric multilayer film laminated on at least one main surface side of the substrate, The substrate has at least one layer of resin film containing a dye (IR) and a resin, The total thickness of the aforementioned resin film is 0.3 to 20 μm. The optical filter is an optical filter that satisfies all of the following optical characteristics (i-1) to (i-4) and (i-7) to (i-10). (i-1) The average reflectance R on at least one surface of the optical filter at a wavelength of 450 to 500 nm and an incident angle of 5 degrees. ４５０－５００（５ｄｅｇ）ＡＶＥ The average reflectance R at an incident angle of 40 degrees is 3% or less. ４５０－５００（４０ｄｅｇ）ＡＶＥ less than 5% (i-2) The average reflectance R on at least one surface of the optical filter at a wavelength of 500 to 580 nm and an incident angle of 5 degrees. ５００－５８０（５ｄｅｇ）ＡＶＥ The average reflectance R at an incident angle of 40 degrees is 2.5% or less. ５００－５８０（４０ｄｅｇ）ＡＶＥ less than 4% (i-3) On at least one surface of the optical filter, the following relationships are satisfied: R 450-500 (5deg) AVE > R 500-580 (5deg) AVE and R 450-500 (40deg) AVE > R 500-580 (40deg) AVE (i-4) The maximum reflectance R on at least one surface of the optical filter at a wavelength of 450 to 580 nm and an incident angle of 5 degrees. ４５０－５８０（５ｄｅｇ）ＭＡＸ The maximum reflectance R is 4% or less and at an incident angle of 40 degrees. ４５０－５８０（４０ｄｅｇ）ＭＡＸ less than 6% (i-7) Average transmittance T at an incident angle of 0 degrees in the wavelength range of 450 to 580 nm. ４５０－５８０（０ｄｅｇ）ＡＶＥ over 88% (i-8) In the wavelength range of 600 to 800 nm, the absolute difference between the wavelength at which the transmittance is 20% at an incident angle of 0 degrees and the wavelength at which the transmittance is 20% at an incident angle of 40 degrees is 10 nm or less. (i-9) In the wavelength range of 600-800 nm, the wavelength at which the transmittance is 20% at an incident angle of 0 degrees is in the range of 640-690 nm. (i - 10) At a wavelength of 750 to 1000 nm, the maximum transmittance T at an incident angle of 0 degrees ７５０－１０００（０ｄｅｇ）ＭＡＸ is 1% or less, and the maximum transmittance T at an incident angle of 40 degrees ７５０－１０００（４０ｄｅｇ）ＭＡＸ is 1% or less

2. The optical filter according to claim 1, wherein the optical filter satisfies the following optical characteristics (i-5) and (i-6). (i-5) In the wavelength range of 450-500 nm, the maximum difference between the transmittance at an incident angle of 0 degrees and the transmittance at an incident angle of 40 degrees is 6% or less. (i-6) In the wavelength range of 500 to 580 nm, the maximum 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.

3. The optical filter according to claim 1 or 2, wherein the resin film satisfies all of the following optical properties (ii-1) to (ii-6). (ii-1) Average internal transmittance T at wavelengths of 450-580 nm ４５０－５８０ＡＶＥ over 88% (ii-2) At wavelengths of 600-700 nm, the wavelength at which the internal transmittance is 20% is in the range of 640-690 nm. (ii-3) Internal transmittance T at a wavelength of 700 nm ７００ less than 1% (ii-4) Internal transmittance T at a wavelength of 750 nm ７５０ less than 10% (ii-5) Internal transmittance T at a wavelength of 800 nm ８００ less than 20% (ii-6) Internal transmittance T at a wavelength of 950 nm ９５０ 60% to 95%

4. The optical filter according to any one of claims 1 to 3, wherein the dielectric multilayer film satisfies all of the following optical properties (iv-1) to (iv-8). (iv-1) Average transmittance T at an incident angle of 0 degrees in the wavelength range of 450-580 nm ４５０－５８０（０ｄｅｇ）ＡＶＥ The transmittance is 90% or more, and the average transmittance at an incident angle of 40 degrees is T. ４５０－５８０（４０ｄｅｇ）ＡＶＥ over 90% (iv-2) In the wavelength range of 450-500 nm, the absolute 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) In the wavelength range of 500-580 nm, the absolute 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. (iv-4) In the wavelength range of 450-500 nm, the maximum difference between the transmittance at an incident angle of 0 degrees and the transmittance at an incident angle of 40 degrees is 6% or less. (iv-5) In the wavelength range of 500-580 nm, the maximum 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. (iv-6) In the wavelength range of 600-800 nm, the wavelength at which the transmittance at an incident angle of 0 degrees is 20% is in the range of 720-770 nm. (iv-7) Maximum transmittance T at an incident angle of 0 degrees in the wavelength range of 780-850 nm ７８０－８５０（０ｄｅｇ）ＭＡＸ 4% to less than 10% (iv-8) Maximum transmittance T at an incident angle of 40 degrees in wavelengths of 900-980 nm ９００－９８０（４０ｄｅｇ）ＭＡＸ 1% or more but less than 5%

5. The aforementioned dye (IR) is A compound (A) having a maximum absorption wavelength in dichloromethane between 690 nm and 735 nm. A compound (B) having a maximum absorption wavelength in dichloromethane between 735 nm and 835 nm. An optical filter according to any one of claims 1 to 4, comprising one or more compounds selected from each of the compounds (C) having a maximum absorption wavelength of 900 nm to 1000 nm in dichloromethane.

6. The optical filter according to claim 5, wherein the maximum difference between the maximum absorption wavelength of compound (A) and the maximum absorption wavelength of compound (B) is 40 nm or more.

7. The optical filter according to any one of claims 1 to 6, wherein the substrate comprises a support and the resin film.

8. The optical filter according to claim 7, wherein the support is any of phthalate glass, phosphate glass, soda-lime glass, borosilicate glass, alkali-free glass, or quartz glass.

9. The optical filter according to any one of claims 1 to 8, having one layer of the aforementioned resin film.

10. The optical filter according to any one of claims 1 to 9, having two or more layers of the aforementioned resin film.

11. An information acquisition device comprising an optical filter according to any one of claims 1 to 10.

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