Optical filter

Abstract

An object of the present invention is to provide an optical filter which has a high visible-light transmitting property and a high light-blocking property against light in the range of wavelengths of 1000 to 1200nm and in which a decrease in the light-blocking property against ultraviolet light and near-infrared light at a high incident angle is suppressed.SOLUTION: The present invention relates to an optical filter including a base material and a dielectric multilayer film laminated as an outermost layer on at least one principal surface side of the base material, in which the base material includes a dye (U) having a maximum absorption band at 380 to 425nm in dichloromethane, a dye (A) having a maximum absorption band at 690 to 730nm in dichloromethane, and a polymer, and the optical filter satisfies all of specific spectral characteristics (i- 1) to (i- 8).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 ultraviolet and near-infrared wavelength regions. [Background technology]

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

[0003] Such optical filters can be made in various ways, for example, by laminating dielectric thin films with different refractive indices alternately on one or both sides of a transparent substrate (dielectric multilayer film), and using optical interference to reflect light that needs to be blocked, such as a reflective filter.

[0004] Here, human visibility is said to be up to about 700 nm, while the sensitivity of image sensors installed in imaging devices is said to be up to about 1200 nm. If light enters the sensor without blocking the near-infrared region above 700 nm, the image will differ from what the human eye sees, raising concerns about reduced image reproducibility. To bring the sensitivity ranges of both closer together and correct color tones, there is a demand for optical filters that block light in the near-infrared wavelength region, particularly the 1000-1200 nm wavelength region.

[0005] Furthermore, optical filters with dielectric multilayer films have problems such as changes in the optical thickness of the dielectric multilayer film depending on the angle of incidence of light, resulting in variations in the spectral transmittance curve with the angle of incidence, light leakage due to high transmittance of ultraviolet and near-infrared light, which should have high reflectance at high angles of incidence, and noise due to ultraviolet and near-infrared light reflected by the dielectric multilayer film. The use of such filters can potentially affect the spectral sensitivity of solid-state imaging devices depending on the angle of incidence. In particular, with the recent trend toward thinner camera modules, use at higher angles of incidence is expected. Therefore, there has been a demand for optical filters that can block ultraviolet and near-infrared light without significantly affecting the transmittance of visible light and independent of the angle of incidence.

[0006] Patent Document 1 describes an optical filter having an average transmittance of 5% or less in the wavelength range of 1100 to 1200 nm. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2018 / 043564 Summary of the Invention [Problem to be solved by the invention]

[0008] The optical filter described in Patent Document 1 achieves low transmittance in the wavelength range of 1100 to 1200 nm by adding a dye having an absorption band in this range. However, since such a dye also has an absorption band in the visible range, transmittance is reduced not only in the long wavelength range but also in the visible range.

[0009] Therefore, an object of the present invention is to provide an optical filter that has high transmittance for visible light, high blocking ability for light in the wavelength range of 1000 to 1200 nm, and that suppresses a decrease in blocking ability for ultraviolet light and near-infrared light at high angles of incidence. [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 as an outermost layer on at least one main surface side of the substrate, the substrate has a resin film containing a dye (U) having a maximum absorption wavelength in dichloromethane of 380 to 425 nm, a dye (A) having a maximum absorption wavelength in dichloromethane of 690 to 730 nm, and a resin; The optical filter satisfies all of the following spectral characteristics (i-1) to (i-8). (i-1) Average transmittance T in the spectral transmittance curve at wavelengths of 1000 to 1200 nm and an incident angle of 0 degrees 1000-1200(0deg)AVE is 1.5% or less (i-2) Average transmittance T in the spectral transmittance curve at a wavelength of 1000 to 1200 nm and an incident angle of 40 degrees 1000-1200(40deg)AVE is less than 10% (i-3) Average transmittance T in the spectral transmittance curve at wavelengths of 440 to 600 nm and an incident angle of 0 degrees 440-600(0deg)AVE Over 90% (i-4) Average transmittance T in the spectral transmittance curve at wavelengths of 440 to 600 nm and an incident angle of 40 degrees 440-600(40deg)AVE Over 83% (i-5) UV50 wavelength at which transmittance is 50% at an incident angle of 0 degrees (0deg) is in the range of 420-435 nm (i-6) The wavelength at which the transmittance is 20% at a wavelength of 350 to 450 nm and an incident angle of 0 degrees is called UV20. (0deg) The wavelength when the transmittance is 40% is called UV40. (0deg) The wavelength at which the transmittance is 50% is called UV50 (0deg) year, The wavelength at which the transmittance is 20% at a wavelength of 350 to 450 nm and an incident angle of 40 degrees is called UV20. (40deg) The wavelength when the transmittance is 40% is called UV40. (40deg) The wavelength at which the transmittance is 50% is called UV50 (40deg) When UV20 (0deg) and UV20 (40deg) The absolute value of the difference is 12 nm or less. UV40(0deg) and UV40 (40deg) The absolute value of the difference is 12 nm or less. UV50 (0deg) and UV50 (40deg) The absolute difference is 12 nm or less (i-7) The wavelength at which the transmittance is 20% at a wavelength of 640 to 700 nm and an incident angle of 0 degrees is called IR20 (0deg) year, The wavelength at which the transmittance is 20% at a wavelength of 640 to 700 nm and an incident angle of 40 degrees is called IR20. (40deg) When IR20 (0deg) and IR20 (40deg) The absolute value of the difference is 15 nm or less (i-8) Wavelength IR20 at which transmittance is 20% at an incident angle of 0 degrees (0deg) is in the range of 640-700 nm [Effects of the Invention]

[0011] According to the present invention, an optical filter can be provided that has high transmittance for visible light, high blocking ability for light in the wavelength range of 1000 to 1200 nm, and suppresses a decrease in blocking ability for ultraviolet light and near-infrared light at high angles of incidence. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view schematically illustrating an example of an optical filter according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view schematically showing another example of the optical filter according to the embodiment. [Figure 3] FIG. 3 is a cross-sectional view schematically showing another example of the optical filter according to the embodiment. [Figure 4] FIG. 4 is a cross-sectional view schematically showing another example of the optical filter according to the embodiment. [Figure 5] FIG. 5 is a diagram showing the spectral transmittance curve of the optical filter of Example 3-1. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the present invention will be described. In this specification, the near-infrared absorbing dye may be abbreviated as "NIR dye" and the ultraviolet absorbing dye may be abbreviated as "UV dye". In this specification, a 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, a 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, the internal transmittance is the transmittance obtained by subtracting the influence of interface reflection from the measured transmittance, as expressed by the formula {measured transmittance / (100-reflectance)}×100. In this specification, the transmittance of a substrate and the transmittance of a resin film, including a case where a dye is contained in the resin, are all referred to as "internal transmittance" even when they are referred to as "transmittance." On the other hand, the transmittance measured by dissolving a dye in a solvent such as dichloromethane and the transmittance of an optical filter having a dielectric multilayer film are actually measured transmittances.

[0015] In this specification, for example, a transmittance of 90% or more in a specific wavelength range means that the transmittance is not less than 90% across the entire wavelength range, i.e., the minimum transmittance is 90% or more across the wavelength range. Similarly, for example, a transmittance of 1% or less in a specific wavelength range means that the transmittance is not more than 1% across the entire wavelength range, i.e., the maximum transmittance is 1% or less across the wavelength range. The same applies to internal transmittance. The average transmittance and average internal transmittance in a specific wavelength range are the arithmetic mean of the transmittance and internal transmittance per 1 nm in the wavelength range. In this specification, the use of "to" to indicate a range of values ​​includes the upper and lower limits.

[0016] <Optical filters> An optical filter according to one embodiment of the present invention (hereinafter also referred to as "the present filter") comprises a substrate and a dielectric multilayer film laminated as an outermost layer on at least one main surface of the substrate, and satisfies specific spectral characteristics described below. The substrate has a resin film containing a dye (U) having a maximum absorption wavelength in dichloromethane between 380 and 425 nm, a dye (A) having a maximum absorption wavelength in dichloromethane between 690 and 730 nm, and a resin. The dye (U) is a UV dye, and the dye (A) is an NIR dye. By including a dye that absorbs ultraviolet and near-infrared light in the substrate, the absorption characteristics of the substrate can suppress degradation of the spectral characteristics of the dielectric multilayer film at high angles of incidence, such as light leakage and noise in the ultraviolet and near-infrared regions. The dyes and resins will be described below.

[0017] An example of the configuration of the present filter will be described with reference to the drawings. Figures 1 to 4 are cross-sectional views that schematically show an example of an optical filter according to an embodiment. 1 is an example in which a dielectric multilayer film 30 is provided on one main surface side of a substrate 10. Note that "having a specific layer on the main surface side of the substrate" does not only mean that the layer is provided in contact with the main surface of the substrate, but also includes a case in which another functional layer is provided between the substrate and the layer.

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

[0019] 3 is an example in which a substrate 10 has a support 11 and a resin film 12 laminated on one main surface 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 of the support 11 on which the resin film 12 is not laminated.

[0020] 4 is an example in which a substrate 10 has a support 11 and resin films 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 spectral characteristics (i-1) to (i-8). (i-1) Average transmittance T in the spectral transmittance curve at wavelengths of 1000 to 1200 nm and an incident angle of 0 degrees 1000-1200(0deg)AVE is 1.5% or less (i-2) Average transmittance T in the spectral transmittance curve at a wavelength of 1000 to 1200 nm and an incident angle of 40 degrees 1000-1200(40deg)AVE is less than 10% (i-3) Average transmittance T in the spectral transmittance curve at wavelengths of 440 to 600 nm and an incident angle of 0 degrees 440-600(0deg)AVE Over 90% (i-4) Average transmittance T in the spectral transmittance curve at wavelengths of 440 to 600 nm and an incident angle of 40 degrees 440-600(40deg)AVE Over 83% (i-5) UV50 wavelength at which transmittance is 50% at an incident angle of 0 degrees (0deg) is in the range of 420-435 nm (i-6) The wavelength at which the transmittance is 20% at a wavelength of 350 to 450 nm and an incident angle of 0 degrees is called UV20. (0deg) The wavelength when the transmittance is 40% is called UV40. (0deg) The wavelength at which the transmittance is 50% is called UV50 (0deg) year, The wavelength at which the transmittance is 20% at a wavelength of 350 to 450 nm and an incident angle of 40 degrees is called UV20. (40deg) The wavelength when the transmittance is 40% is called UV40. (40deg) The wavelength at which the transmittance is 50% is called UV50 (40deg) When UV20 (0deg) and UV20 (40deg) The absolute value of the difference is 12 nm or less. UV40 (0deg) and UV40 (40deg) The absolute value of the difference is 12 nm or less. UV50 (0deg) and UV50 (40deg) The absolute difference is 12 nm or less (i-7) The wavelength at which the transmittance is 20% at a wavelength of 640 to 700 nm and an incident angle of 0 degrees is called IR20 (0deg) year, The wavelength at which the transmittance is 20% at a wavelength of 640 to 700 nm and an incident angle of 40 degrees is called IR20. (40deg) When IR20 (0deg) and IR20 (40deg) The absolute value of the difference is 15 nm or less (i-8) Wavelength IR20 at which transmittance is 20% at an incident angle of 0 degrees (0deg) is in the range of 640-700 nm

[0022] This filter, which satisfies all of the spectral characteristics (i-1) to (i-8), is an optical filter that has high transmittance for visible light, high blocking ability for light in the wavelength range of 1000 to 1200 nm, and suppresses the decrease in blocking ability for ultraviolet light and near-infrared light at high angles of incidence.

[0023] Satisfying the spectral characteristic (i-1) means that the shielding property is excellent in the range of 1000 to 1200 nm. 1000-1200(0deg)AVE is preferably 1% or less, more preferably 0.7% or less.

[0024] By satisfying the spectral characteristic (i-2), it means that the blocking property in the range of 1000 to 1200 nm is excellent even at a high angle of incidence. 1000-1200(40deg)AVE is preferably 8% or less, more preferably 7% or less.

[0025] Satisfying the spectral characteristics (i-3) means that the film has excellent transmittance in the visible light range. 440-600(0deg)AVE is preferably 91% or more, more preferably 92% or more.

[0026] By satisfying the spectral characteristics (i-4), it means that the transmittance of visible light is excellent even at high angles of incidence. 440-600(40deg)AVE is preferably 85% or more, more preferably 88% or more.

[0027] The spectral characteristic (i-5) means that the UV blocking band is shifted toward longer wavelengths, which enhances the blocking ability in the 1000 to 1200 nm wavelength range. (0deg)is preferably in the range of 420 to 430 nm.

[0028] By satisfying the spectral characteristic (i-6), it means that there is little shift even at high incident angles and excellent color reproducibility in the UV absorption start band of wavelengths 350 to 450 nm. (0deg) and UV20 (40deg) The absolute value of the difference between the UV40 and UV50 is preferably 10 nm or less, more preferably 9 nm or less. (0deg) and UV40 (40deg) The absolute value of the difference between the UV50 and UV60 is preferably 10 nm or less, more preferably 9 nm or less. (0deg) and UV50 (40deg) The absolute value of the difference between is preferably 8 nm or less, and more preferably 7 nm or less.

[0029] By satisfying the spectral characteristics (i-7), it means that there is little shift even at high angles of incidence and excellent color reproducibility in the NIR absorption onset band of wavelengths 640 to 700 nm. (0deg) and IR20 (40deg) The absolute value of the difference between is preferably 13 nm or less, and more preferably 12 nm or less.

[0030] By satisfying the spectral characteristics (i-8), it is possible to cut the near-infrared wavelength range from 700 nm onwards, and it means that a large amount of visible light can be captured. (0deg) is preferably in the range of 650 to 680 nm.

[0031] The optical filter of the present invention preferably further satisfies the following spectral characteristic (i-9). (i-9) The wavelength at which the transmittance is 10% at a wavelength of 350 to 450 nm and an incident angle of 0 degrees is called UV10. (0deg) The wavelength at which the transmittance is 50% is called UV50 (0deg) When UV10 (0deg) and UV50 (0deg) The absolute value of the difference is 15 nm or less

[0032] Satisfying the spectral characteristic (i-9) means that the slope of the spectral transmittance curve is steep in the UV absorption onset band of wavelengths from 350 to 450 nm. The spectral characteristic (i-9) is more preferably 8 nm or less, and particularly preferably 7 nm or less.

[0033] The substrate and the dielectric multilayer film are described below. This filter is designed, for example, by imparting ultraviolet and near-infrared absorption capabilities to the substrate, and by using the absorption characteristics of the substrate and the reflection characteristics of the dielectric multilayer film to satisfy the above-mentioned spectral characteristics (i-1) to (i-8).

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

[0035] In the present filter, it is preferable that the dielectric multilayer film satisfies all of the following spectral characteristics (iv-1) to (iv-8). (iv-1) Wavelength UV50 where transmittance is 50% at an incident angle of 0 degrees (0deg) is in the range of 420-430 nm (iv-2) Average transmittance T in the spectral transmittance curve at wavelengths of 440 to 600 nm and an incident angle of 0 degrees 440-600(0deg)AVE Over 90% (iv-3) Minimum transmittance T in the spectral transmittance curve at wavelengths of 440 to 600 nm and an incident angle of 0 degrees 440-600(0deg)MIN Over 90% (iv-4) Average transmittance T in the spectral transmittance curve at wavelengths of 440 to 600 nm and an incident angle of 40 degrees 440-600(40deg)AVE Over 90% (iv-5) Minimum transmittance T in the spectral transmittance curve at wavelengths of 440 to 600 nm and an incident angle of 40 degrees 440-600(40deg)MIN Over 80% (iv-6) Wavelength IR20 at which transmittance is 20% at an incident angle of 0 degrees (0deg) is in the range of 680-740 nm (iv-7) Average transmittance T in the spectral transmittance curve at wavelengths of 1000 to 1200 nm and an incident angle of 0 degrees 1000-1200(0deg)AVE is 1.5% or less (iv-8) Average transmittance T in the spectral transmittance curve at wavelengths of 1000 to 1200 nm and an incident angle of 40 degrees 1000-1200(40deg)AVE is less than 10%

[0036] Meeting the spectral characteristics (iv-1) means that the center of the UV-blocking band is between 420 and 430 nm. (0deg) is preferably in the range of 420 to 427 nm.

[0037] Satisfying the spectral characteristics (iv-2) means that the film has excellent transmittance in the visible light range. 440-600(0deg)AVE is preferably 91% or more, more preferably 92% or more.

[0038] Satisfying the spectral characteristics (iv-3) means that the film has excellent transmittance in the visible light range. 440-600(0deg)MIN is preferably 91% or more, more preferably 92% or more.

[0039] By satisfying the spectral characteristics (iv-4), it means that the transmittance of visible light is excellent even at high angles of incidence. 440-600(40deg)AVE is preferably 91% or more, more preferably 92% or more.

[0040] By satisfying the spectral characteristics (iv-5), it means that the transmittance of visible light is excellent even at high angles of incidence. 440-600(40deg)MIN is preferably 82% or more, more preferably 85% or more.

[0041] By satisfying the spectral characteristics (iv-6), it is possible to create an optical filter that blocks light in the near-infrared wavelength range from 700 nm onwards and has little dependence on the angle of incidence. (0deg) is preferably in the range of 660 to 700 nm, more preferably in the range of 660 to 690 nm.

[0042] By satisfying the spectral characteristic (iv-7), it means that the film has excellent light-blocking properties in the long wavelength region of 1000 to 1200 nm. 1000-1200(0deg)AVEis preferably 1.2% or less, more preferably 1% or less.

[0043] By satisfying the spectral characteristic (iv-8), it means that the film has excellent light-blocking properties in the long wavelength region of 1000 to 1200 nm even at high incident angles. 1000-1200(40deg)AVE is preferably 9% or less, more preferably 8% or less.

[0044] The transmission band of the dielectric multilayer film can be shifted to either a longer or shorter wavelength side by adjusting the film thickness of the multilayer film. In the present invention, by shifting the entire light-blocking band of the multilayer film to a longer wavelength side as shown in characteristics (iv-1) and (iv-6), the multilayer film can block the 1000 to 1200 nm band as shown in characteristic (iv-7). This allows for an optical filter with excellent light-blocking properties in the 1000 to 1200 nm range to be obtained, as shown in the above spectral characteristic (i-1). On the other hand, shifting the entire light-shielding band toward longer wavelengths to block light from 1000 to 1200 nm tends to result in a shift toward oblique incidence in the ultraviolet region from 400 to 430 nm. This shift toward oblique incidence is preferably compensated for by the absorption characteristics of the UV dye (U) described below. Specifically, by incorporating a UV dye satisfying the spectral characteristic (ii-1) described below, i.e., a UV dye with a steep slope in the UV absorption region from 400 to 430 nm, into the resin film, a resin film satisfying the spectral characteristic (iii-4) described below, i.e., a resin film with a steep slope in the UV absorption region from 400 to 430 nm, can be obtained. Combining this resin film with the dielectric multilayer film described above results in an optical filter in which the shift toward oblique incidence in the ultraviolet region is suppressed, as shown in the spectral characteristic (i-6) described above.

[0045] In this filter, at least one of the dielectric multilayer films is preferably designed as a near-infrared reflective layer (hereinafter also referred to as an NIR reflective layer), and the other of the dielectric multilayer films is preferably designed as an NIR reflective layer, a reflective layer having a reflection range other than the near-infrared range, or an anti-reflection layer.

[0046] The NIR reflective layer is a dielectric multilayer film designed to block light in the near-infrared region. The NIR reflective layer has 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 reflective region of the NIR reflective layer may include the light-shielding region of the resin film in the near-infrared region. The NIR reflective layer is not limited to NIR reflection characteristics, and may be appropriately designed to further block light in wavelength regions other than the near-infrared region, for example, the near-ultraviolet region.

[0047] The NIR reflective layer is composed of, for example, a dielectric multilayer film in which dielectric films with low refractive index (low refractive index film) and dielectric films with high refractive index (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 materials for the high refractive index film include Ta2O5, TiO2, and Nb2O5. Of these, TiO2 is preferred in terms of film formability, reproducibility in refractive index, etc., and stability.

[0048] 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 materials for the low refractive index film include SiO2, SiO x N y In terms of reproducibility, stability, economy, etc. in film formation, SiO2 is preferred.

[0049] To shift the light-blocking band of the NIR reflective layer toward longer wavelengths, several types of dielectric multilayer films with different spectral characteristics can be combined to transmit and select the desired wavelength band. In this case, the light-blocking band can be shifted to longer wavelengths by increasing the film thickness without changing the film thickness ratio of silica and titania that make up the multilayer film. Specifically, the desired light-blocking band can be adjusted by increasing the thickness of the silica and titania by 1 to 8%. In order to shift the light-shielding band to the longer wavelength side and shield the 1000 to 1200 nm region of the NIR reflective layer, the total number of laminated dielectric multilayer films constituting the reflective layer is preferably 20 or more, more preferably 30 or more, and even more preferably 35 or more. This number of laminated layers is preferable because it allows the dielectric multilayer film to shield the 1000 to 1200 nm region and also allows for a steep change in transmittance in the boundary wavelength region between the transmission region and the light-shielding region. However, since a large total number of laminated layers can cause warping or an increase in film thickness, the total number of laminated layers is preferably 100 or less, more preferably 75 or less, and even more preferably 60 or less. The overall thickness of the reflective layer is preferably 2 to 10 μm.

[0050] If the total number of layers and thickness of the dielectric multilayer film are within the above ranges, the NIR reflective layer satisfies the requirement for miniaturization, and the incidence angle dependency can be suppressed while maintaining high productivity.

[0051] The dielectric multilayer film can be formed by vacuum film-forming processes such as CVD, sputtering, and vacuum deposition, or wet film-forming processes such as spraying and dipping.

[0052] The NIR reflective layer may be a single layer (a group of dielectric multilayer films) that provides predetermined optical characteristics, or two layers that provide predetermined optical characteristics. When there are two or more layers, the reflective layers may have the same or different configurations. 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 blocks light in the short wavelength band of the near-infrared region, and the other may be a near-infrared / near-ultraviolet reflective layer that blocks light in both the long wavelength band of the near-infrared region and the near-ultraviolet region.

[0053] Examples of antireflection layers include dielectric multilayer films, intermediate refractive index media, and moth-eye structures in which the refractive index changes gradually. Among these, dielectric multilayer films are preferred from the viewpoints of optical efficiency and productivity. Antireflection layers are obtained by alternately laminating dielectric multilayer films, similar to reflective layers.

[0054] <Base material> In the optical filter of the present invention, the substrate has a resin film containing the dye (U) and the dye (A) described below and a resin.

[0055] <Spectral characteristics of resin film> The resin film preferably satisfies all of the following spectral properties (iii-1) to (iii-6). (iii-1) The internal transmittance in the spectral transmittance curve at a wavelength of 400 nm is 2% or less (iii-2) Average internal transmittance T in the spectral transmittance curve at wavelengths of 400 to 420 nm 400-420AVE is less than 5% (iii-3) The wavelength UV50 at which the internal transmittance is 50% is in the range of 415 to 440 nm. (iii-4) In the wavelength range of 400 to 430 nm, when the wavelength when the internal transmittance is 10% is UV10, and when the wavelength when the internal transmittance is 50% is UV50, The absolute difference between UV10 and UV50 is 15nm or less (iii-5) Average internal transmittance T in the spectral transmittance curve at wavelengths of 440 to 550 nm 440-550AVE Over 93% (iii-6) The wavelength IR20 at which the internal transmittance is 20% is in the range of 650 to 700 nm.

[0056] By satisfying the spectral characteristic (iii-1), it means that the film has excellent light-blocking properties against ultraviolet light in the vicinity of 400 nm. 400 is preferably 1.5% or less, more preferably 1% or less.

[0057] By satisfying the spectral characteristic (iii-2), it means that the film has excellent light-blocking properties against ultraviolet light of 400 to 420 nm. 400-420AVE is preferably 4.5% or less, more preferably 4% or less.

[0058] Satisfying the spectral characteristic (iii-3) means that the center of the UV-cut band is in the range of 415 to 440 nm. UV50 is preferably in the range of 420 to 435 nm.

[0059] By satisfying the spectral characteristic (iii-4), it means that in the UV absorption start band of wavelengths 400 to 430 nm, the slope of the spectral transmittance curve is steep. The spectral characteristic (iii-4) is preferably 14 nm or less, more preferably 13 nm or less.

[0060] By satisfying the spectral characteristic (iii-5), it means that the transmittance in the visible light region is excellent. T 440-550AVE is preferably 94% or more, more preferably 95% or more.

[0061] By satisfying the spectral characteristic (iii-6), it means that an optical filter with a small oblique incidence shift can be obtained in combination with the above dielectric multilayer film that shields the region after 700 nm while transmitting visible light. In the spectral characteristic (iii-6), IR20 is preferably in the range of 660 to 690 nm.

[0062] The resin film preferably further satisfies the following spectral characteristics (iii-7) and (iii-8). (iii-7) The average internal transmittance T in the spectral transmittance curve at wavelengths 350 to 390 nm 350-390AVE is 10% or less (iii-8) The average internal transmittance T in the spectral transmittance curve at wavelengths 400 to 430 nm 400-430AVE is 15% or less

[0063] By satisfying the spectral characteristic (iii-7) and the spectral characteristic (iii-8), it means that ultraviolet light can be widely shielded. T 350-390AVE is preferably 9% or less, more preferably 8% or less. T 400-430AVE is preferably 14% or less, more preferably 13% or less.

[0064] <UV dye> The dye (U) is a UV dye having a maximum absorption wavelength at 380 to 425 nm in dichloromethane. By containing such a dye, ultraviolet light can be effectively cut.

[0065] The dye (U) has a maximum absorption wavelength in dichloromethane preferably from 385 to 420 nm, more preferably from 390 to 420 nm.

[0066] Furthermore, the dye (U) preferably satisfies the following spectral characteristic (ii-1). (ii-1) In the wavelength range of 400 to 430 nm, when the wavelength at which the transmittance in dichloromethane is 10% is UV10, and when the wavelength at which the transmittance is 50% is UV50, The absolute value of the difference between UV10 and UV50 is preferably 18 nm or less, more preferably 16 nm or less

[0067] Satisfying the spectral characteristic (ii-1) means that the slope of the spectral transmission curve is steep in the UV absorption onset band.

[0068] Examples of the dye (U) include oxazole dyes, merocyanine dyes, cyanine dyes, naphthalimide dyes, oxadiazole dyes, oxazine dyes, oxazolidine dyes, naphthalic acid dyes, styryl dyes, anthracene dyes, cyclic carbonyl dyes, and triazole dyes. Among these, merocyanine dyes are particularly preferred. One type may be used alone, or two or more types may be used in combination.

[0069] As the dye (U), a merocyanine dye represented by the following formula (M) is particularly preferred.

[0070] [ka]

[0071] The symbols in formula (M) are as follows:

[0072] R 1 represents a monovalent hydrocarbon group having 1 to 12 carbon atoms which may have a substituent. The substituent is preferably an alkoxy group, an acyl group, an acyloxy group, a cyano group, a dialkylamino group, or a chlorine atom. The alkoxy group, acyl group, acyloxy group, and dialkylamino group preferably have 1 to 6 carbon atoms.

[0073] Unsubstituted R 1 Specifically, preferred are alkyl groups having 1 to 12 carbon atoms in which some of the hydrogen atoms may be substituted with an aliphatic ring, an aromatic ring, or an alkenyl group; cycloalkyl groups having 3 to 8 carbon atoms in which some of the hydrogen atoms may be substituted with an aromatic ring, an alkyl group, or an alkenyl group; and aryl groups having 6 to 12 carbon atoms in which some of the hydrogen atoms may be substituted with an aliphatic ring, an alkyl group, or an alkenyl group.

[0074] R 1 When is an unsubstituted alkyl group, the alkyl group may be linear or branched, and more preferably has 1 to 6 carbon atoms.

[0075] R 1 is an alkyl group having 1 to 12 carbon atoms in which some of the hydrogen atoms are substituted with an aliphatic ring, an aromatic ring, or an alkenyl group, an alkyl group having 1 to 4 carbon atoms having a cycloalkyl group having 3 to 6 carbon atoms, or an alkyl group having 1 to 4 carbon atoms substituted with a phenyl group is more preferred, and an alkyl group having 1 or 2 carbon atoms substituted with a phenyl group is particularly preferred. Note that an alkyl group substituted with an alkenyl group means an alkenyl group as a whole that does not have an unsaturated bond between the 1- and 2-positions, such as an allyl group or a 3-butenyl group.

[0076] Preferred R 1 is an alkyl group having 1 to 6 carbon atoms in which some of the hydrogen atoms may be substituted with a cycloalkyl group or a phenyl group. Particularly preferred is Q 1 is an alkyl group having 1 to 6 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a t-butyl group.

[0077] R 2 ~R5 each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms. The alkyl group and alkoxy group preferably have 1 to 6 carbon atoms, and more preferably 1 to 4 carbon atoms.

[0078] R 2 and R 3 At least one of R is preferably an alkyl group, and more preferably both are alkyl groups. 2 and R 3 When R is not an alkyl group, a hydrogen atom is more preferred. 2 and R 3 In any case, an alkyl group having 1 to 6 carbon atoms is particularly preferred.

[0079] R 4 and R 5 At least one of R is preferably a hydrogen atom, and more preferably both are hydrogen atoms. 4 or R 5 When is not a hydrogen atom, it is preferably an alkyl group having 1 to 6 carbon atoms.

[0080] Y is R 6 and R 7 represents a methylene group or an oxygen atom substituted with R 6 and R 7 each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms.

[0081] X represents any one of the divalent groups represented by the following formulas (X1) to (X5).

[0082] [ka]

[0083] R 8 and R 9 each independently represents a monovalent hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, and R 10 ~R19 each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms which may have a substituent. R 8 ~R 19 The substituents of R 1 The same substituents as those in R are mentioned, and the preferred embodiments are also the same. 8 ~R 19 is a hydrocarbon group having no substituents, R 1 The same aspects as above can be mentioned.

[0084] In formula (X1), R 8 and R 9 may be different groups, but are preferably the same group. 8 and R 9 When is an unsubstituted alkyl group, it may be linear or branched, and more preferably has 1 to 6 carbon atoms.

[0085] Preferred R 8 and R 9 Each of R is an alkyl group having 1 to 6 carbon atoms in which some of the hydrogen atoms may be substituted with a cycloalkyl group or a phenyl group. 8 and R 9 are all alkyl groups having 1 to 6 carbon atoms, and specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a t-butyl group.

[0086] In formula (X2), R 10 and R 11 are more preferably alkyl groups having 1 to 6 carbon atoms, and it is particularly preferred that they are the same alkyl groups.

[0087] In formula (X3), R 12 and R 15 are preferably both hydrogen atoms or unsubstituted alkyl groups having 1 to 6 carbon atoms. 13 and R 14are preferably all hydrogen atoms or all alkyl groups having 1 to 6 carbon atoms.

[0088] In formula (X4), two groups R bonded to the same carbon atom 16 and R 17 and R 18 and R 19 are preferably all hydrogen atoms or all alkyl groups having 1 to 6 carbon atoms.

[0089] As the compound (M), the following compounds (M1), (M2) and (M3) are preferred. Compound (M1) is a compound represented by the formula (M), wherein Y is R 6 and R 7 and X represents a divalent group represented by formula (X1). The compound (M2) is a compound in which Y in formula (M) represents an oxygen atom and X represents a divalent group represented by formula (X1). Compound (M3) is a compound represented by the formula (M), wherein Y is R 6 and R 7 and X represents a divalent group represented by formula (X2).

[0090] The dye (U) preferably contains a compound (M1) having a maximum absorption wavelength of around 420 nm and a steep spectral curve in the vicinity of the ultraviolet absorption band. Furthermore, it is more preferable that the dye (U) contains a compound (M1) and a compound (M2). By combining two types of UV dyes, the average transmittance in the range of 400 to 420 nm can be reduced. Furthermore, it is particularly preferable that the dye (U) contains the compounds (M1), (M2), and (M3). By combining three types of UV dyes, the average transmittance can be reduced in the 400 to 430 nm wavelength range, i.e., in a wider wavelength range.

[0091] Specific examples of the compound (M1) that can be used as the dye (U) include the compounds shown in the table below.

[0092] [Table 1]

[0093] Specific examples of the compound (M2) that can be used as the dye (U) include the compounds shown in the table below.

[0094] [Table 2]

[0095] Specific examples of the compound (M3) that can be used as the dye (U) include the compounds shown in the table below.

[0096] [Table 3]

[0097] Among these, compounds M1-1 to M1-4 are preferred as compound (M) from the viewpoints of solubility in resins and solvents, visible light transmittance, maximum absorption wavelength, and particularly satisfying the optical property (ii-1). Compounds M2-5 to M2-8 are preferred from the viewpoints of solubility in resins and solvents, visible light transmittance, maximum absorption wavelength, and ease of synthesis. Compounds M3-5 to M3-8 are preferred from the viewpoints of solubility in resins and solvents, visible light transmittance, and maximum absorption wavelength. When two compounds (M) having different structures are used in combination, a combination of one selected from compounds M1-1 to M1-4 and one selected from compounds M2-5 to M2-8 is preferred from the viewpoint of efficiently broadening the absorption band from 400 to 430 nm. When three compounds (M) having different structures are used in combination, a combination of one selected from compounds M1-1 to M1-4, one selected from compounds M2-5 to M2-8, and one selected from compounds M3-5 to M3-8 is preferred from the viewpoint of efficiently broadening the absorption band from 400 to 430 nm and the short wavelength band from 350 to 395 nm. The compound (M) can be produced by a known method.

[0098] The content of the UV dye (U) in the resin film is preferably 0.1 to 15 parts by mass, more preferably 1 to 10 parts by mass, relative to 100 parts by mass of the resin. Within such a range, it is less likely to cause a decrease in resin properties.

[0099] <NIR dye> In the optical filter of the present invention, the base material contains the above-mentioned dye (U) and a dye (A). The dye (A) is a NIR dye having a maximum absorption wavelength in the range of 690 to 730 nm in dichloromethane. By containing such a dye, infrared light can be effectively cut.

[0100] As the dye (A), at least one selected from the group consisting of squarylium dyes, cyanine dyes, phthalocyanine dyes, naphthalocyanine dyes, dithiol metal complex dyes, azo dyes, polymethine dyes, phthalide dyes, naphthoquinone dyes, anthraquinone dyes, indophenol dyes, pyrylium dyes, thiopyrylium dyes, croconium dyes, tetradehydrookorine dyes, triphenylmethane dyes, aminium dyes and diimonium dyes is preferable. Among these NIR dyes, squarylium dyes are preferable from the spectroscopic viewpoint.

[0101] As the squarylium dye, the compound represented by the following formula (I) is preferable.

[0102]

Chemical formula

[0103] However, the symbols in the formula (I) are as follows. R 24 and R 26 are each independently a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group or an alkoxy group having 1 to 6 carbon atoms, an acyloxy group having 1 to 10 carbon atoms, -NR 27 R 28 (R 27 and R 28are each independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or -C(=O)-R 29 (R 29 represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an aryl group having 6 to 11 carbon atoms, or an araryl group having 7 to 18 carbon atoms which may have a substituent and which may have an oxygen atom between the carbon atoms), -NHR 30 , or -SO2-R 30 (R 30 represents a hydrocarbon group having 1 to 25 carbon atoms, each of which may have one or more hydrogen atoms substituted with a halogen atom, a hydroxyl group, a carboxyl group, a sulfo group, or a cyano group, and which may contain an unsaturated bond, an oxygen atom, or a saturated or unsaturated ring structure between carbon atoms), or a group represented by the following formula (S): 41 , R 42 are independently a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 10 carbon atoms. k is 2 or 3.

[0104] [ka]

[0105] R 21 and R 22 , R 22 and R 25 , and R 21 and R 23 may be linked to each other to form, together with the nitrogen atom, 5- or 6-membered heterocycles A, B, and C, respectively.

[0106] R when heterocycle A is formed 21 and R 22 represents a divalent group -Q- to which they are bonded, which is an alkylene group or alkyleneoxy group in which a hydrogen atom may be substituted with an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an acyloxy group having 1 to 10 carbon atoms which may have a substituent.

[0107] R when heterocycle B is formed 22 and R 25and R when heterocycle C is formed. 21 and R 23 are the divalent groups -X 1 -Y 1 - and -X 2 -Y 2 -(The side that is bonded to nitrogen is X 1 and X 2 ) as X 1 and X 2 are groups represented by the following formula (1x) or (2x), and Y 1 and Y 2 are each a group selected from the following formulas (1y) to (5y): 1 and X 2 are groups represented by the following formula (2x), Y 1 and Y 2 may each be a single bond, in which case: An oxygen atom may be present between the carbon atoms.

[0108] [ka]

[0109] In formula (1x), four Z's each independently represent 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 R each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. 31 ~R 36 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms, R 37 represents an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms.

[0110] R 27 , R 28 , R 29 , R 31 ~R 37 , R when not forming a heterocycle 21 ~R23 , and R 25 may be bonded to any other of these to form a 5- or 6-membered ring. 31 and R 36 , R 31 and R 37 may be directly bonded.

[0111] When a heterocyclic ring is not formed, R 21 and R 22 are each independently a hydrogen atom, an alkyl group or aryl group having 1 to 6 carbon atoms which may have a substituent, or an aryl group or araryl group having 6 to 11 carbon atoms which may have a substituent. When no heterocycle is formed, R 23 and R 25 are each independently a hydrogen atom, a halogen atom, or an alkyl or alkoxy group having 1 to 6 carbon atoms.

[0112] As the compound (I), for example, a compound represented by formula (I-1) is preferred from the viewpoint of increasing the visible light transmittance.

[0113] [ka]

[0114] The symbols in formula (I-1) have the same definitions as those of the same symbols in formula (I), and the preferred embodiments are also the same.

[0115] In compound (I-1), X 1 As the group (2x), the group (2x) is preferred. 1 is preferably a single bond or a group (1y). 31 ~R 36 is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom or a methyl group. 1 -X 1 Specific examples of - include divalent organic groups represented by formulas (11-1) to (12-3).

[0116] -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)

[0117] In addition, in compound (I-1), R 21 are more preferably independently a group represented by formula (4-1) or formula (4-2) from the viewpoints of solubility, heat resistance, and the steepness of the change in the spectral transmittance curve near the boundary between the visible region and the near-infrared region.

[0118] [ka]

[0119] In formula (4-1) and formula (4-2), R 71 ~R 75 are independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms.

[0120] In compound (I-1), R 24 From the viewpoint of increasing the transmittance of visible light, especially light with a wavelength of 430 to 550 nm, -NH-SO2-R 30 is preferred. In compound (I-1), R 24 -NH-SO2-R 30 The compound is shown in formula (I-12).

[0121] [ka]

[0122] R in compound (I-12)23 and R 26 are each independently preferably a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms, and more preferably a hydrogen atom.

[0123] In compound (I-12), R 30 From the viewpoint of light resistance, R is preferably an alkyl group having 1 to 12 carbon atoms, which may be branched, an alkoxy group having 1 to 12 carbon atoms, which may be branched, or a hydrocarbon group having 6 to 16 carbon atoms and an unsaturated ring structure. Examples of the unsaturated ring structure include benzene, toluene, xylene, furan, and benzofuran. 30 are more preferably independently an alkyl group having 1 to 12 carbon atoms which may have a branch or an alkoxy group having 1 to 12 carbon atoms which may have a branch. 30 In each group represented by the formula (I), some or all of the hydrogen atoms may be substituted with halogen atoms, particularly fluorine atoms.

[0124] Compound (I) can be produced by known methods, for example, as described in U.S. Pat. No. 5,543,086, U.S. Patent Application Publication No. 2014 / 0061505, and WO 2014 / 088063.

[0125] The content of the NIR dye (A) in the resin film is preferably 0.1 to 15 parts by mass, more preferably 1 to 10 parts by mass, based on 100 parts by mass of the resin.

[0126] <Base material composition> The substrate in the present filter may have a single-layer structure or a multi-layer structure, and the material of the substrate is not particularly limited, and may be an organic or inorganic material as long as it is a transparent material that transmits visible light of 400 to 700 nm. When the substrate has a single layer structure, it is preferable that the substrate is a resin substrate made of a resin film containing a resin, a UV dye (U), and a NIR dye (A). When the substrate has a multilayer structure, a composite substrate is preferred in which a resin film containing the UV dye (U) and the NIR dye (A) 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.

[0127] The resin is not limited as long as it is a transparent resin, and one or more transparent resins selected from polyester resin, acrylic resin, epoxy resin, enethiol resin, polycarbonate resin, polyether resin, polyarylate resin, polysulfone resin, polyethersulfone resin, polyparaphenylene resin, polyarylene ether phosphine oxide resin, polyamide resin, polyimide resin, polyamideimide resin, polyolefin resin, cyclic olefin resin, polyurethane resin, polystyrene resin, etc. These resins may be used alone or in combination of two or more. From the viewpoint of the spectral characteristics, glass transition temperature (Tg) and adhesiveness of the resin film, one or more resins selected from polyimide resin, polycarbonate resin, polyester resin and acrylic resin are preferred.

[0128] The UV dye (U) and the NIR dye (A) may be contained in the same resin film, or may be contained in separate resin films.

[0129] As the transparent inorganic material, glass or crystalline material is preferred. Examples of glass that can be used for the support include absorption-type glass (near-infrared absorbing glass) containing copper ions in fluorophosphate glass or phosphate glass, soda-lime glass, borosilicate glass, alkali-free glass, and quartz glass. As the glass, phosphate glass and fluorophosphate glass are preferred from the viewpoint of absorbing infrared light (particularly 1000 to 1200 nm). Note that "phosphate glass" also includes silicophosphate glass, in which part of the glass skeleton is composed of SiO2.

[0130] The glass may be chemically strengthened glass obtained by ion exchange at a temperature equal to or lower than the glass transition point to exchange alkali metal ions (e.g., Li ions, Na ions) having a small ionic radius present on the main surface of the glass plate with alkali ions having a larger ionic radius (e.g., Na ions or K ions for Li ions, and K ions for Na ions).

[0131] Examples of crystalline materials that can be used for the support include birefringent crystals such as quartz, lithium niobate, and sapphire.

[0132] As the support, inorganic materials are preferred, and glass and sapphire are particularly preferred, from the viewpoint of shape stability related to long-term reliability of optical properties, mechanical properties, etc., and ease of handling during filter production.

[0133] The resin film can be formed by dissolving or dispersing the dye (U) and dye (A), the resin or resin raw materials, and other optional components in a solvent to prepare a coating solution, applying the coating solution to a support, drying, and optionally curing the coating solution. The support may be the support included in the filter, or a peelable support used only when forming the resin film. The solvent may be any suitable dispersion medium or solvent capable of stably dispersing the dye (U) and dye (A).

[0134] The coating liquid may also contain a surfactant to prevent voids caused by microbubbles, depressions caused by the adhesion of foreign matter, and repellency during the drying process. For example, the coating liquid can be applied by dip coating, cast coating, or spin coating. After the coating liquid is applied to a support, a resin film is formed by drying. When the coating liquid contains raw materials for a transparent resin, it is further subjected to a curing treatment such as thermal curing or photocuring.

[0135] The resin film can also be produced in the form of a film by extrusion molding. When the substrate has a single-layer structure (resin substrate) consisting of a resin film containing the dye (U) and the dye (A), the resin film can be used as is as the substrate. When the substrate has a multi-layer structure (composite substrate) having a support and a resin film containing the dye (U) and the dye (A) laminated on at least one main surface of the support, the substrate can be produced by laminating this film on the support and integrating them by thermocompression bonding or the like.

[0136] The optical filter may have one resin film layer or two or more resin films. When the optical filter has two or more resin films, the layers may have the same or different configurations.

[0137] When the substrate has a single layer structure (resin substrate) made of a resin film containing the dye (U) and the dye (A), the thickness of the resin film is preferably 50 to 150 μm. When the substrate has a multilayer structure (composite substrate) having a support and a resin film containing the dye (A) laminated on at least one main surface of the support, the thickness of the resin film is preferably 0.3 to 20 μm.

[0138] The shape of the substrate is not particularly limited, and may be a block, plate, or film. The thickness of the substrate is preferably 300 μm or less from the viewpoints of reducing warpage during the formation of the dielectric multilayer film and reducing the height of the optical element. When the substrate is a resin substrate made of a resin film, the thickness is preferably 50 to 300 μm, and when the substrate is a composite substrate comprising a support and a resin film, the thickness is preferably 100 to 300 μm.

[0139] The filter may also include other components, such as a component (layer) that provides absorption by inorganic fine particles that control the transmission and absorption of light in a specific wavelength range. Specific examples of inorganic fine particles include ITO (indium tin oxide), ATO (antimony-doped tin oxide), cesium tungstate, and lanthanum boride. ITO fine particles and cesium tungstate fine particles have high transmittance for visible light and absorb light over a wide range of infrared wavelengths exceeding 1200 nm, and therefore can be used when blocking such infrared light is required.

[0140] When used in an imaging device such as a digital still camera, this filter can provide an imaging device with excellent color reproducibility. An imaging device using this filter includes a solid-state imaging element, an imaging lens, and this filter. This filter can be used, for example, by being placed between the imaging lens and the solid-state imaging element, or by being directly attached to the solid-state imaging element, imaging lens, etc. of the imaging device via an adhesive layer. [Example]

[0141] Next, the present invention will be explained more specifically with reference to examples. Each optical property was measured using an ultraviolet-visible spectrophotometer (UH-4150, manufactured by Hitachi High-Technologies Corporation). Unless the angle of incidence is specifically stated, the spectral characteristics are values ​​measured at an angle of incidence of 0 degrees (perpendicular to the main surface of the optical filter).

[0142] The dyes used in each example are as follows: Compounds 1 to 17 are UV dyes, and compounds 18 and 19 are NIR dyes. Compound 1 (merocyanine compound): Synthesized with reference to Japanese Patent No. 6504176. Compound 2: Nikkafluor U1 manufactured by Nippon Chemical Industry Co., Ltd. was used. Compound 3 (cyanine compound): SMP-416 manufactured by Hayashibara Chemical Industry Co., Ltd. was used. Compound 4 (cyanine compound): SMP-370 manufactured by Hayashibara Chemical Industry Co., Ltd. was used. Compound 5 (cyanine compound): SMP-471 manufactured by Hayashibara Chemical Industry Co., Ltd. was used. Compound 6: Kayalight 408 manufactured by Nippon Kayaku Co., Ltd. was used. Compound 7: Kayalight B manufactured by Nippon Kayaku Co., Ltd. was used. Compound 8: Nikkafluor MCT manufactured by Nippon Chemical Industry Co., Ltd. was used. Compound 9 (merocyanine compound): Synthesized with reference to Japanese Patent No. 6504176. Compound 10 (merocyanine compound): Synthesized with reference to Japanese Patent No. 6504176. Compound 11 (benzoxazole compound): UVITEX OB, manufactured by Tokyo Chemical Industry Co., Ltd. Compound 12 (merocyanine compound): Synthesized with reference to Japanese Patent No. 6504176. Compound 13 (merocyanine compound): Synthesized with reference to Japanese Patent No. 6504176. Compound 14 (azo compound): Synthesized with reference to Japanese Patent No. 6256335. Compound 15 (merocyanine compound): Synthesized with reference to Japanese Patent No. 6504176. Compound 16 (triazine compound): Synthesized with reference to Japanese Patent No. 6256335. Compound 17 (merocyanine compound): Synthesized with reference to Japanese Patent No. 6504176. Compound 18: Synthesized with reference to Japanese Patent No. 605169. Compound 19: Synthesized with reference to Japanese Patent No. 4800769.

[0143] [ka]

[0144] [ka]

[0145] [Chemistry]

[0146] <Examples 1-1 to 1-6: Spectral Characteristics of Dielectric Multilayer Films> On a glass substrate (alkali glass, D263 manufactured by Schott), 42-layer dielectric multilayer films 1 to 6 were produced by alternately depositing TiO2 films and SiO2 films by vapor deposition. The refractive index of the SiO2 film was 1.47, and the refractive index of the TiO2 film was 2.39. Also, the thickness ratio of the SiO2 film / TiO2 film was within the range of 0.9 to 1.1. Further, the film thickness of each multilayer film was as shown in the following table. The spectral characteristics at incident angles of 0 degrees and 40 degrees are shown in the following table. Note that Examples 1-1 to 1-6 are reference examples.

[0147] [Table 4]

[0148] <Spectral Characteristics of UV Dye in Dichloromethane>[ Each dye was uniformly dissolved in dichloromethane. For each of the obtained solutions, using a spectrophotometer, the maximum absorption wavelength, the wavelength UV50 when the transmittance was 50% at wavelengths of 350 to 450 nm, the wavelength UV10 when the transmittance was 10% at wavelengths of 350 to 450 nm, and the absolute value of the difference between the wavelength UV50 when the transmittance was 50% (UV50 - UV10) were measured. The results are shown in the following table.

[0149] [Table 5]

[0150] <Example 2-1: Spectral Characteristics of Resin Film>[ 100 parts by mass of polyimide resin (C-3G30G manufactured by Mitsubishi Gas Chemical Company) was mixed with 2 parts by mass of compound 1, 3.3 parts by mass of compound 12, and 4 parts by mass of compound 18, and an organic solvent (a mixed solvent of gamma-butyrolactone and cyclohexanone) was added, followed by stirring 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 resin film 1 with a thickness of 2 μm.

[0151] <Examples 2-2 to 2-5> Resin films 2 to 5 were obtained in the same manner as in Example 2-1, except that the type and content of the dye were as shown in the table below.

[0152] The spectral internal transmittance curve was calculated using the spectral transmittance curve and the spectral reflectance curve of this resin film-coated glass substrate. The spectral characteristics are shown in the table below. Examples 2-1 to 2-5 are reference examples.

[0153] [Table 6]

[0154] <Spectral characteristics of optical filters> <Example 3-1> Multilayer film 4 of Example 1-4 was formed on a glass substrate (alkali glass, D263 manufactured by Schott). Resin layer 1 of Example 2-1 was formed thereon by spin coating. Then, an anti-reflection film made of seven layers of silica / titania was formed on resin layer 1 to produce an absorption-type infrared cut filter. The transmission spectrum of the obtained infrared cut filter was measured using a spectrophotometer in the wavelength range of 350 nm to 1200 nm at incident angles of 0 degrees and 40 degrees. The results are shown in the table below. The spectral transmittance curve is shown in Figure 5.

[0155] <Examples 3-2 to 3-7, 3-9 to 3-12> An infrared cut filter was prepared in the same manner as in Example 3-1 except that the types of multilayer film and resin film were combined as shown in the table below, and the transmission spectrum was measured. The results are shown in the table below.

[0156] <Example 3-8> An infrared cut filter was prepared in the same manner as in Example 3-1, except that the support used was changed from an alkali glass substrate to a fluorophosphate glass substrate (NF50T manufactured by AGC, plate thickness 0.2 mm), and the transmission spectrum was measured. The results are shown in the table below.

[0157] Examples 3-1 to 3-3, 3-8, and 3-9 are working examples, and Examples 3-4 to 3-7 and 3-10 to 3-12 are comparative examples. UV20 shift amount: UV20 (0deg) and UV20 (40deg) Absolute value of the difference between UV40 shift amount: UV40 (0deg) and UV40 (40deg) Absolute value of the difference between UV50 shift amount: UV50 (0deg) and UV50 (40deg) Absolute value of the difference between IR20 shift amount: IR20 (0deg) and IR20 (40deg) Absolute value of the difference between

[0158] [Table 7]

[0159] From the above results, it can be seen that the optical filters of Examples 3-1 to 3-3, 3-8, and 3-9 have good light blocking properties in the near-infrared region, particularly in the 1000 to 1200 nm region, and have excellent transmittance in the visible region of 440 to 600 nm. Example 3-8 has better light blocking properties in the 1000 to 1200 nm region than Example 3-1, because the glass substrate itself, which serves as the support, is absorbent. On the other hand, the optical filter of Example 3-4, which used a resin film 3 with a high average internal transmittance in the range of 400 to 420 nm, resulted in a large UV20 shift amount and poor oblique incidence characteristics. Furthermore, the optical filters of Examples 3-5 and 3-7, which shielded the 1000 to 1200 nm region by the absorption ability of the dye contained in the resin film, also absorbed the visible light region of 440 to 600 nm, resulting in low transmittance. Furthermore, the optical filters of Examples 3-6, 3-7, 3-10 to 3-12, which used multilayer films 1, 2 or 3 in which UV50 was less than 420 nm, i.e., the light-blocking region was not shifted to longer wavelengths and the light-blocking properties in the 1000 to 1200 nm region were low, resulted in low light-blocking properties in the 1000 to 1200 nm region.

[0160] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application (Patent Application No. 2020-158813) filed on September 23, 2020, the contents of which are incorporated herein by reference. [Industrial Applicability]

[0161] The optical filter of the present invention has high transmittance for visible light, high blocking ability for light in the wavelength range of 1000 to 1200 nm, and good near-infrared light blocking properties, in which the decrease in blocking ability for ultraviolet light and near-infrared light at high incident angles is suppressed. It is useful for applications in information acquisition devices, such as cameras and sensors for transport aircraft, which have been increasingly sophisticated in recent years. [Explanation of symbols]

[0162] 1A, 1B, 1C, 1D...optical filter, 10...substrate, 11...support, 12...resin film, 30...dielectric multilayer film

Claims

1. An optical filter comprising a substrate and a dielectric multilayer film on at least one main surface side of the substrate, the substrate has a resin film containing a dye (U) having a maximum absorption wavelength in dichloromethane of 380 to 425 nm, a dye (A) having a maximum absorption wavelength in dichloromethane of 690 to 730 nm, and a resin; The optical filter satisfies all of the following spectral characteristics (i-2) and (i-4) to (i-8). (i-2) Average transmittance T in the spectral transmittance curve at a wavelength of 1000 to 1200 nm and an incident angle of 40 degrees １０００－１２００（４０ｄｅｇ）ＡＶＥ is less than 10% (i-4) Average transmittance T in the spectral transmittance curve at a wavelength of 440 to 600 nm and an incident angle of 40 degrees ４４０－６００（４０ｄｅｇ）ＡＶＥ Over 83% (i-5) Wavelength UV50 at which the transmittance is 50% at an incident angle of 0 degrees （０ｄｅｇ） is in the range of 420 to 435 nm (i-6) The wavelength at which the transmittance is 20% at a wavelength of 350 to 450 nm and an incident angle of 0 degrees is called UV20. （０ｄｅｇ） The wavelength at which the transmittance is 40% is UV40 （０ｄｅｇ） The wavelength at which the transmittance is 50% is called UV50. （０ｄｅｇ） year, At a wavelength of 350 to 450 nm and an incident angle of 40 degrees, the wavelength at which the transmittance is 20% is called UV20. （４０ｄｅｇ） The wavelength at which the transmittance is 40% is UV40 （４０ｄｅｇ） The wavelength at which the transmittance is 50% is called UV50. （４０ｄｅｇ） When UV20 （０ｄｅｇ） and UV20 （４０ｄｅｇ） The absolute value of the difference is 12 nm or less, UV40 （０ｄｅｇ） and UV40 （４０ｄｅｇ） The absolute value of the difference is 12 nm or less, UV50 （０ｄｅｇ） and UV50 （４０ｄｅｇ） The absolute value of the difference is 12 nm or less (i-7) At a wavelength of 640 to 700 nm and an incident angle of 0 degrees, the wavelength at which the transmittance is 20% is defined as IR20 （０ｄｅｇ） year, The wavelength at which the transmittance is 20% at a wavelength of 640 to 700 nm and an incident angle of 40 degrees is called IR20. （４０ｄｅｇ） When IR20 （０ｄｅｇ） and IR20 （４０ｄｅｇ） The absolute value of the difference is 15 nm or less (i-8) Wavelength IR20 at which the transmittance is 20% at an incident angle of 0 degrees （０ｄｅｇ） is in the range of 640 to 700 nm

2. 2. The optical filter according to claim 1, wherein the optical filter further satisfies the following spectral characteristic (i-1): (i-1) Average transmittance T in the spectral transmittance curve at a wavelength of 1000 to 1200 nm and an incident angle of 0 degrees １０００－１２００（０ｄｅｇ）ＡＶＥ is 1.5% or less

3. In the requirement (i-2), the average transmittance T １０００－１２００（４０ｄｅｇ）ＡＶＥ 3. The optical filter according to claim 1, wherein the .lambda.

4. The optical filter according to any one of claims 1 to 3, wherein the optical filter further satisfies the following spectral characteristic (i-3): (i-3) Average transmittance T in the spectral transmittance curve at a wavelength of 440 to 600 nm and an incident angle of 0 degrees ４４０－６００（０ｄｅｇ）ＡＶＥ More than 90%

5. The optical filter according to any one of claims 1 to 4, wherein the optical filter further satisfies the following spectral characteristic (i-9): (i-9) The wavelength at which the transmittance is 10% at a wavelength of 350 to 450 nm and an incident angle of 0 degrees is called UV10. （０ｄｅｇ） The wavelength at which the transmittance is 50% is called UV50. （０ｄｅｇ） When UV10 （０ｄｅｇ） and UV50 （０ｄｅｇ） The absolute value of the difference is 15 nm or less

6. 6. The optical filter according to claim 1, wherein the dielectric multilayer film satisfies all of the following spectral characteristics (iv-1) to (iv-8): (iv-1) Wavelength UV50 at which the transmittance is 50% at an incident angle of 0 degrees （０ｄｅｇ） is in the range of 420 to 430 nm (iv-2) Average transmittance T in the spectral transmittance curve at a wavelength of 440 to 600 nm and an incident angle of 0 degrees ４４０－６００（０ｄｅｇ）ＡＶＥ More than 90% (iv-3) Minimum transmittance T in the spectral transmittance curve at a wavelength of 440 to 600 nm and an incident angle of 0 degrees ４４０－６００（０ｄｅｇ）ＭＩＮ More than 90% (iv-4) Average transmittance T in the spectral transmittance curve at a wavelength of 440 to 600 nm and an incident angle of 40 degrees ４４０－６００（４０ｄｅｇ）ＡＶＥ More than 90% (iv-5) Minimum transmittance T in the spectral transmittance curve at a wavelength of 440 to 600 nm and an incident angle of 40 degrees ４４０－６００（４０ｄｅｇ）ＭＩＮ More than 80% (iv-6) Wavelength IR20 at which the transmittance is 20% at an incident angle of 0 degrees （０ｄｅｇ） is in the range of 680 to 740 nm (iv-7) Average transmittance T in the spectral transmittance curve at a wavelength of 1000 to 1200 nm and an incident angle of 0 degrees １０００－１２００（０ｄｅｇ）ＡＶＥ is 1.5% or less (iv-8) Average transmittance T in the spectral transmittance curve at a wavelength of 1000 to 1200 nm and an incident angle of 40 degrees １０００－１２００（４０ｄｅｇ）ＡＶＥ is less than 10%

7. 7. The optical filter according to claim 1, wherein the resin film satisfies all of the following spectral characteristics (iii-1) to (iii-6). (iii-1) The internal transmittance in the spectral transmittance curve at a wavelength of 400 nm is 2% or less. (iii-2) Average internal transmittance T in the spectral transmittance curve at wavelengths of 400 to 420 nm ４００－４２０ＡＶＥ is less than 5% (iii-3) The wavelength UV50 at which the internal transmittance is 50% is in the range of 415 to 440 nm. (iii-4) In the wavelength range of 400 to 430 nm, when the wavelength when the internal transmittance is 10% is UV10, and when the wavelength when the internal transmittance is 50% is UV50, The absolute difference between UV10 and UV50 is 15 nm or less (iii-5) Average internal transmittance T in the spectral transmittance curve at wavelengths of 440 to 550 nm ４４０－５５０ＡＶＥ Over 93% (iii-6) The wavelength IR20 at which the internal transmittance is 20% is in the range of 650 to 700 nm.

8. 8. The optical filter according to claim 1, wherein the resin film further satisfies the following spectral characteristics (iii-7) to (iii-8). (iii-7) Average internal transmittance T in the spectral transmittance curve at wavelengths of 350 to 390 nm ３５０－３９０ＡＶＥ is less than 10% (iii-8) Average internal transmittance T in the spectral transmittance curve at wavelengths of 400 to 430 nm ４００－４３０ＡＶＥ is less than 15%

9. 9. The optical filter according to claim 1, wherein the dye (U) comprises a compound represented by the following formula (M): 【Chemistry 1】 The symbols in formula (M) are as follows. R １ represents a monovalent hydrocarbon group having 1 to 12 carbon atoms which may have a substituent. R ２ ~R ５ each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms. Y is R ６ and R ７ represents a methylene group or an oxygen atom substituted with R ６ and R ７ each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms. X represents any one of the divalent groups represented by the following formulas (X1) to (X5) (where R ８ and R ９ each independently represents a monovalent hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, R １０ ~R １９ each independently represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms which may have a substituent. 【Chemistry 2】

10. The dye (U) In the formula (M), Y is R ６ and R ７ 10. The optical filter according to claim 9, comprising a compound in which X is a methylene group substituted with X, and X is a divalent group represented by formula (X1).

11. The dye (U) In the formula (M), Y is R ６ and R ７ a compound in which X is a divalent group represented by formula (X1); The optical filter according to claim 9 , comprising a compound in which in the formula (M), the Y is an oxygen atom and the X is a divalent group represented by the formula (X1).

12. The dye (U) In the formula (M), Y is R ６ and R ７ a compound in which X is a divalent group represented by formula (X1); a compound in which Y in the formula (M) is an oxygen atom and X is a divalent group represented by the formula (X1); In the formula (M), Y is R ６ and R ７ and a compound in which X is a divalent group represented by formula (X2).

13. The optical filter according to any one of claims 1 to 12, wherein the dye (A) comprises a squarylium dye.

14. The optical filter according to any one of claims 1 to 13, wherein the substrate includes a support and the resin film, the resin film is laminated on at least one main surface of the support, and the support includes phosphate glass or fluorophosphate glass.

15. 15. The optical filter according to claim 1, wherein the resin is a transparent resin.

16. An imaging device comprising the optical filter according to any one of claims 1 to 15.

Images