optical filter

Abstract

The present invention is a filter having a substrate and a dielectric multilayer film, wherein the dielectric multilayer film is stacked on at least one main surface side of the substrate and serves as the outermost layer, wherein the substrate has a resin film comprising a pigment (IR) and a resin, wherein the pigment (IR) has a maximum absorption wavelength in the resin in the range of 680 nm to 800 nm, and the filter satisfies specific spectral characteristics (i-1) to (i-23) in the spectral transmittance curves under incident angles of 0 degrees, 30 degrees, and 70 degrees.

Description

Technical Field

[0001] This invention relates to a filter that transmits light in the visible wavelength range and blocks light in the near-infrared wavelength range. Background Technology

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

[0003] For such filters, examples include: diffusing filters that alternately stack dielectric films with different refractive indices (dielectric multilayer films) on one or both sides of a transparent substrate and use light interference to reflect the light that is to be blocked.

[0004] Optical filters with dielectric multilayer films suffer from several problems. The optical thickness of the multilayer film varies with the angle of incidence, leading to variations in the spectral transmittance profile caused by the angle of incidence. These problems include light leakage due to increased transmittance of near-infrared light, which should have high reflectivity at high angles of incidence, and noise caused by near-infrared light reflected from the multilayer film. When using such filters, the spectral sensitivity of solid-state imaging elements may be affected by the angle of incidence. In particular, with the recent reduction in camera module height, applications under high angle-of-incidence conditions are envisioned.

[0005] Here, the sensitivity of the image sensor mounted in the imaging device reaches its maximum in the vicinity of 700nm to 850nm, so a filter is required that has almost no effect on the visible light transmittance and can block light in this near-infrared region even at high incident angles.

[0006] Patent Document 1 describes a filter that uses a substrate with a sufficiently strong absorption band near 700 nm and a wide absorption band in the near-infrared wavelength range above 900 nm as a filter that can simultaneously suppress color shading and ghosting in camera images at a high level.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: International Publication No. 2018 / 043564 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] However, the filter described in Patent Document 1 uses near-infrared absorbing pigments with a maximum absorption wavelength of 800 nm or more, thereby reducing the transmittance in the visible light region.

[0012] Therefore, the object of the present invention is to provide a filter having high transmittance of visible light and high blocking power of near-infrared light above 700 nm, and suppressing the reduction of blocking power of near-infrared light above 700 nm at high incident angles.

[0013] means for solving problems

[0014] The present invention provides a filter having the following configuration.

[0015] [1] A filter having a substrate and a dielectric multilayer film, the dielectric multilayer film being stacked on at least one main surface side of the substrate and serving as the outermost layer, wherein,

[0016] The substrate has a resin film comprising a pigment (IR) and a resin.

[0017] The pigment (IR) has a maximum absorption wavelength in the resin in the range of 680 nm to 800 nm, and

[0018] The filter satisfies all of the following spectral characteristics (i-1) to (i-23):

[0019] Spectral characteristics (i-1) to (i-9) in the spectral transmittance curve under the condition of 0 degrees incident angle:

[0020] (i-1) Average transmittance T in the wavelength range of 440 nm to 490 nm 440-490(0度)AVE It is over 85%;

[0021] (i-2) Average transmittance T in the wavelength range of 490 nm to 560 nm 490-560(0度)AVE It is over 90%;

[0022] (i-3) Average transmittance T in the wavelength range of 560 nm to 590 nm 560-590(0度)AVE It is over 83%;

[0023] (i-4) Wavelength IR50 when transmittance is 50% (0度) Within the range of 600nm to 680nm;

[0024] (i-5) Maximum transmittance T in the wavelength range of 700 nm to 760 nm 700-760(0度)MAX Less than 2%;

[0025] (i-6) Transmittance T at a wavelength of 750 nm750(0度) Less than 0.5%;

[0026] (i-7) Maximum transmittance T in the wavelength range of 760 nm to 800 nm 760-800(0度)MAX Less than 1%;

[0027] (i-8) Maximum transmittance T in the wavelength range of 800 nm to 900 nm 800-900(0度)MAX Less than 1%;

[0028] (i-9) Maximum transmittance T in the wavelength range of 900 nm to 1100 nm 900-1100(0度)MAX Less than 1%;

[0029] Spectral characteristics (i-10) to (i-18) in the spectral transmittance curve under the condition of an incident angle of 30 degrees:

[0030] (i-10) Average transmittance T in the wavelength range of 440 nm to 490 nm 440-490(30度)AVE It is over 84%;

[0031] (i-11) Average transmittance T in the wavelength range of 490 nm to 560 nm 490-560(30度)AVE It is over 90%;

[0032] (i-12) Average transmittance T in the wavelength range of 560 nm to 590 nm 560-590(30度)AVE It is over 83%;

[0033] (i-13) Wavelength IR50 when transmittance is 50% (30度) Within the range of 600nm to 680nm;

[0034] (i-14) Maximum transmittance T in the wavelength range of 700 nm to 760 nm 700-760(30度)MAX Less than 2%;

[0035] (i-15) Transmittance T at a wavelength of 750 nm 750(30度) Less than 0.5%;

[0036] (i-16) Maximum transmittance T in the wavelength range of 760 nm to 800 nm 760-800(30度)MAX Less than 1%;

[0037] (i-17) Maximum transmittance T in the wavelength range of 800 nm to 900 nm 800-900(30度)MAX Less than 1%;

[0038] (i-18) Maximum transmittance T in the wavelength range of 900 nm to 1100 nm 900-1100(30度)MAX Less than 5%;

[0039] (i-19) wavelength IR50 (0度) With the wavelength IR50 (30度) The absolute value of the difference is less than 8nm;

[0040] Spectral characteristics (i-20) to (i-23) in the spectral transmittance curve under the condition of an incident angle of 70 degrees:

[0041] (i-20) Maximum transmittance T in the wavelength range of 700 nm to 760 nm 700-760(70度)MAX Less than 1.5%;

[0042] (i-21) Transmittance T at a wavelength of 750 nm 750(70度) Less than 1.5%;

[0043] (i-22) Maximum transmittance T in the wavelength range of 760 nm to 800 nm 760-800(70度)MAX Less than 1.5%;

[0044] (i-23) Maximum transmittance T in the wavelength range of 800 nm to 900 nm 800-900(70度)MAX It is below 1.5%.

[0045] Invention Effects

[0046] According to the present invention, a filter can be provided that has high transmittance of visible light and high blocking power for near-infrared light above 700 nm, and suppresses the reduction of blocking power for near-infrared light above 700 nm at high incident angles. Attached Figure Description

[0047] Figure 1 A cross-sectional view is shown schematically as an example of a filter according to one embodiment.

[0048] Figure 2 A cross-sectional view is shown to schematically illustrate another example of a filter according to one embodiment.

[0049] Figure 3 A cross-sectional view is shown to schematically illustrate another example of a filter according to one embodiment.

[0050] Figure 4 A cross-sectional view is shown to schematically illustrate another example of a filter according to one embodiment.

[0051] Figure 5 A graph showing the spectral transmittance curve of the dielectric multilayer film 1 in Example 2-1.

[0052] Figure 6 A graph showing the spectral transmittance curve of the dielectric multilayer film 2 in Example 2-2.

[0053] Figure 7 A graph showing the spectral transmittance curve of the filter in Example 3-11.

[0054] Figure 8 A graph showing the spectral transmittance curve of the filter in Example 3-13. Detailed Implementation

[0055] The embodiments of the present invention will be described below.

[0056] In this specification, near-infrared absorbing pigments are sometimes referred to as "NIR pigments" and ultraviolet absorbing pigments are sometimes referred to as "UV pigments".

[0057] In this specification, compounds represented by formula (I) are referred to as compound (I). The same applies to compounds represented by other formulas. Pigments containing compound (I) are also referred to as pigment (I), and the same applies to other pigments. Furthermore, groups represented by formula (I) are also referred to as group (I), and the same applies to groups represented by other formulas.

[0058] In this specification, internal transmittance refers to the transmittance obtained by subtracting the effect of interface reflection from the measured transmittance, expressed by the formula {measured transmittance / (100 - reflectance)} × 100.

[0059] In this specification, the transmittance of the substrate, the transmittance of the resin film including cases where the resin contains pigments, and the transmittance measured by dissolving the pigments in solvents such as dichloromethane, when described as "transmittance," are all referred to as "internal transmittance." On the other hand, the transmittance of a filter having a dielectric multilayer film is the measured transmittance.

[0060] In this specification, a transmittance of 90% or more for a specific wavelength range means that the transmittance is not less than 90% across the entire wavelength range, i.e., the minimum transmittance within that wavelength range is 90% or more. Similarly, a transmittance of 1% or less for a specific wavelength range means that the transmittance is not greater than 1% across the entire wavelength range, i.e., the maximum transmittance within that wavelength range is 1% or less. The same applies to internal transmittance. The average transmittance and average internal transmittance within a specific wavelength range are the arithmetic mean of the transmittance and internal transmittance per 1 nm within that wavelength range.

[0061] The spectral characteristics can be measured using a UV-Vis spectrophotometer.

[0062] In this specification, the "~" sign indicating a numerical range includes both the upper and lower limits.

[0063] <Filter>

[0064] A filter according to one embodiment of the present invention (hereinafter also referred to as "this filter") is a filter having a substrate and a dielectric multilayer film, the dielectric multilayer film being stacked on at least one main surface side of the substrate and serving as the outermost layer, and the filter satisfying specific spectral characteristics described later.

[0065] Here, the substrate has a resin film comprising a pigment (IR) and resin, wherein the pigment (IR) has a maximum absorption wavelength in the resin in the range of 680 nm to 800 nm. The pigment (IR) is an NIR pigment. By containing a pigment that absorbs near-infrared light in the substrate, the absorption characteristics of the substrate can be utilized to suppress the degradation of the spectral characteristics of the dielectric multilayer film at high incident angles, such as light leakage and noise generation in the near-infrared region. The pigments and resins will be explained later.

[0066] The structure of this filter will be illustrated using the accompanying drawings. Figures 1-4 A cross-sectional view illustrating an example of a filter according to one embodiment.

[0067] Figure 1 The filter 1A shown is an example of having a dielectric multilayer film 30 on one main surface side of the substrate 10. It should be noted that "having a specific layer on the main surface side of the substrate" is not limited to having the layer in contact with the main surface of the substrate, but also includes having other functional layers between the substrate and the layer.

[0068] Figure 2 The filter 1B shown is an example of having a dielectric multilayer film 30 on both main surfaces of the substrate 10.

[0069] Figure 3 The filter 1C shown is an example of a substrate 10 having a support 11 and a resin film 12 laminated on one main surface side of the support 11. The filter 1C further has a dielectric multilayer film 30 on the resin film 12 and a dielectric multilayer film 30 on the unlaminated main surface side of the resin film 12 on the support 11.

[0070] Figure 4 The filter 1D shown is an example of a substrate 10 having a support 11 and resin films 12 laminated on two main surfaces of the support 11. The filter 1D further has a dielectric multilayer film 30 on each resin film 12.

[0071] The filter of the present invention satisfies all of the following spectral characteristics (i-1) to (i-23).

[0072] Spectral characteristics (i-1) to (i-9) in the spectral transmittance curve under the condition of 0 degrees incident angle:

[0073] (i-1) Average transmittance T in the wavelength range of 440 nm to 490 nm 440-490(0度)AVE It is over 85%;

[0074] (i-2) Average transmittance T in the wavelength range of 490 nm to 560 nm 490-560(0度)AVE It is over 90%;

[0075] (i-3) Average transmittance T in the wavelength range of 560 nm to 590 nm 560-590(0度)AVE It is over 83%;

[0076] (i-4) Wavelength IR50 when transmittance is 50% (0度) Within the range of 600nm to 680nm;

[0077] (i-5) Maximum transmittance T in the wavelength range of 700 nm to 760 nm 700-760(0度)MAX Less than 2%;

[0078] (i-6) Transmittance T at a wavelength of 750 nm 750(0度) Less than 0.5%;

[0079] (i-7) Maximum transmittance T in the wavelength range of 760 nm to 800 nm 760-800(0度)MAX Less than 1%;

[0080] (i-8) Maximum transmittance T in the wavelength range of 800 nm to 900 nm 800-900(0度)MAX Less than 1%;

[0081] (i-9) Maximum transmittance T in the wavelength range of 900 nm to 1100 nm 900-1100(0度)MAX It is less than 1%.

[0082] Spectral characteristics (i-10) to (i-18) in the spectral transmittance curve under the condition of an incident angle of 30 degrees:

[0083] (i-10) Average transmittance T in the wavelength range of 440 nm to 490 nm 440-490(30度)AVE It is over 84%;

[0084] (i-11) Average transmittance T in the wavelength range of 490 nm to 560 nm 490-560(30度)AVE It is over 90%;

[0085] (i-12) Average transmittance T in the wavelength range of 560 nm to 590 nm 560-590(30度)AVE It is over 83%;

[0086] (i-13) Wavelength IR50 when transmittance is 50% (30度)Within the range of 600nm to 680nm;

[0087] (i-14) Maximum transmittance T in the wavelength range of 700 nm to 760 nm 700-760(30度)MAX Less than 2%;

[0088] (i-15) Transmittance T at a wavelength of 750 nm 750(30度) Less than 0.5%;

[0089] (i-16) Maximum transmittance T in the wavelength range of 760 nm to 800 nm 760-800(30度)MAX Less than 1%;

[0090] (i-17) Maximum transmittance T in the wavelength range of 800 nm to 900 nm 800-900(30度)MAX Less than 1%;

[0091] (i-18) Maximum transmittance T in the wavelength range of 900 nm to 1100 nm 900-1100(30度)MAX It is below 5%.

[0092] (i-19) The wavelength IR50 mentioned above (0度) Compared with the above wavelength IR50 (30度) The absolute value of the difference is less than 8nm.

[0093] Spectral characteristics (i-20) to (i-23) in the spectral transmittance curve under the condition of an incident angle of 70 degrees:

[0094] (i-20) Maximum transmittance T in the wavelength range of 700 nm to 760 nm 700-760(70度)MAX Less than 1.5%;

[0095] (i-21) Transmittance T at a wavelength of 750 nm 750(70度) Less than 1.5%;

[0096] (i-22) Maximum transmittance T in the wavelength range of 760 nm to 800 nm 760-800(70度)MAX Less than 1.5%;

[0097] (i-23) Maximum transmittance T in the wavelength range of 800 nm to 900 nm 800-900(70度)MAX It is below 1.5%.

[0098] This filter, which satisfies all spectral characteristics (i-1) to (i-23), is a filter with excellent visible light transmittance and near-infrared light blocking properties, and suppresses the reduction of near-infrared light blocking properties at very high incident angles such as 70 degrees.

[0099] The spectral characteristics (i-1) to (i-9) are the characteristics under the condition of an incident angle of 0 degrees.

[0100] By satisfying the spectral characteristic (i-1), it indicates excellent transmittance in the blue light region of 440nm to 490nm. 440-490(0度)AVE Preferably, it is 87% or more, and more preferably 87.5% or more.

[0101] By satisfying the spectral characteristics (i-2), it indicates excellent transmittance in the blue and green light regions of 490nm to 560nm. 490-560(0度)AVE Preferably, it is 92% or more, and more preferably 93% or more.

[0102] By satisfying the spectral characteristics (i-3), it indicates excellent transmittance in the green and yellow light regions of 560nm to 590nm. 560-590(0度)AVE Preferably, it is 84% ​​or more, and more preferably 86% or more.

[0103] By satisfying the spectral characteristics (i-4), it indicates that it can block infrared light and effectively absorb visible transmitted light. IR50 (0度) Preferably, it is in the range of 610nm to 670nm, and more preferably in the range of 620nm to 660nm.

[0104] By satisfying the spectral characteristics (i-5), it indicates excellent blocking properties in the near-infrared region of 700nm to 760nm. 700-760(0度)MAX Preferably, it is 0.7% or less, more preferably 0.5% or less.

[0105] By satisfying the spectral characteristics (i-6), it is indicated that the blocking performance in the 750nm near-infrared region is excellent. 750(0度) Preferably, it is 0.4% or less, more preferably 0.2% or less.

[0106] By satisfying the spectral characteristics (i-7) to (i-9), it indicates excellent blocking properties in the long wavelength range beyond the near-infrared light of 760 nm to 1100 nm.

[0107] T 760-800(0度)MAX Preferably, it is 0.8% or less, more preferably 0.7% or less.

[0108] T 800-900(0度)MAX Preferably, it is 0.8% or less, more preferably 0.7% or less.

[0109] T 900-1100(0度)MAX Preferably, it is 0.8% or less, more preferably 0.7% or less.

[0110] The spectral characteristics (i-10) to (i-18) are those under the condition of an incident angle of 30 degrees.

[0111] By satisfying the spectral characteristics (i-10), it is indicated that the transmittance in the blue light region of 440nm to 490nm is excellent, even at high incident angles. T 440-490(30度)AVE Preferably, it is 84.5% or more, and more preferably 85% or more.

[0112] By satisfying the spectral characteristics (i-11), it is indicated that the transmittance in the blue and green light regions of 490 nm to 560 nm is excellent, even at high incident angles. 490-560(30度)AVE Preferably, it is 91% or more, and more preferably 92% or more.

[0113] By satisfying the spectral characteristics (i-12), it is indicated that the transmittance is excellent even at high incident angles in the green and yellow light regions of 560 nm to 590 nm. 560-590(30度)AVE Preferably, it is 83.5% or more, and more preferably 85.5% or more.

[0114] By satisfying the spectral characteristics (i-13), it is shown that infrared light can be blocked and visible transmitted light can be effectively absorbed even at high incident angles. IR50 (30度) Preferably, it is in the range of 610nm to 670nm, and more preferably in the range of 620nm to 660nm.

[0115] By satisfying the spectral characteristics (i-14), it is indicated that the blocking performance in the near-infrared region of 700 nm to 760 nm is excellent, even at high incident angles. 700-760(30度)MAX Preferably, it is 1.3% or less, more preferably 1.2% or less.

[0116] By satisfying the spectral characteristics (i-15), it is shown that the blocking performance in the near-infrared region of 750 nm is excellent, even at high incident angles. 750(30度) Preferably, it is 0.4% or less, more preferably 0.3% or less.

[0117] By satisfying the spectral characteristics (i-16) to (i-18), it is shown that the blocking performance is excellent even at high incident angles in the long wavelength range beyond the near-infrared light of 760 nm to 1100 nm.

[0118] T 760-800(30度)MAX Preferably, it is 0.5% or less, more preferably 0.4% or less.

[0119] T 800-900(30度)MAX Preferably, it is 0.5% or less, more preferably 0.4% or less.

[0120] T 900-1100(30度)MAX Preferably, it is 4.5% or less, more preferably 4% or less.

[0121] By satisfying the spectral characteristics (i-19), it indicates that the near-infrared light absorption band with wavelengths of 600nm to 680nm shows little shift even at high incident angles, resulting in excellent color reproducibility. The aforementioned wavelength IR50... (0度) Compared with the above wavelength IR50 (30度) The absolute value of the difference is preferably 7nm or less, and more preferably 6nm or less.

[0122] The spectral characteristics (i-20) to (i-23) are those under the condition of an incident angle of 70 degrees.

[0123] By satisfying the spectral characteristics (i-20), it indicates that there is no light leakage even at very high incident angles, and the blocking performance in the near-infrared region of 700nm to 760nm is excellent. 700-760(70度)MAX Preferably, it is 1.4% or less, more preferably 1.3% or less.

[0124] By satisfying the spectral characteristics (i-21), it is indicated that there is no light leakage even at very high incident angles, and the blocking performance in the 750nm near-infrared region is excellent. 750(70度) Preferably, it is 0.7% or less, more preferably 0.6% or less.

[0125] By satisfying the spectral characteristics (i-22)~(i-23), it is indicated that there is no light leakage even at very high incident angles, and the blocking performance is excellent in the long wavelength range beyond the near-infrared light of 760nm~900nm.

[0126] T 760-800(70度)MAX Preferably, it is 1% or less, more preferably 0.8% or less.

[0127] T 800-900(70度)MAX Preferably, it is 1.4% or less, more preferably 1.3% or less.

[0128] The filter of the present invention preferably further comprises a pigment (U) having a maximum absorption wavelength in the resin in the range of 370 nm to 430 nm, and the filter also satisfies the following spectral characteristics (i-24).

[0129] (i-24) In the spectral transmittance curve under the condition of 0 degrees of incident angle, within the wavelength range of 400 nm to 440 nm, the wavelength UV at which the transmittance is 50% is set as UV50. (0度) In the spectral transmittance curve under an incident angle of 30 degrees, within the wavelength range of 400 nm to 440 nm, the wavelength UV at which the transmittance is 50% is set as UV50. (30度) ,at this time,

[0130] The above wavelength UV50 (0度) With the above wavelength UV50 (30度)The absolute value of the difference is less than 5nm.

[0131] The pigment (U) is the UV pigment described later. By having a substrate containing a UV-absorbing pigment, the absorption characteristics of the substrate can be used to suppress the reduction of the spectral characteristics of the dielectric multilayer film at high incident angles, such as the generation of light leakage and noise in the ultraviolet region.

[0132] By satisfying the spectral characteristics (i-24), it indicates that even at high incident angles, the shift is minimal before and after the ultraviolet light absorption initiation band of wavelengths from 400 nm to 440 nm, resulting in excellent color reproducibility. The aforementioned wavelength UV50... (0度) With the above wavelength UV50 (30度) The absolute value of the difference is preferably less than 3nm, and more preferably less than 2nm.

[0133] <Dielectric Multilayer Film>

[0134] In this filter, a dielectric multilayer film is stacked on at least one main surface side of the substrate and serves as the outermost layer.

[0135] In this filter, the dielectric multilayer film preferably satisfies all of the following spectral characteristics (iv-1) to (iv-12).

[0136] Spectral characteristics of the spectral transmittance curves under the condition of 0 degrees of incident angle (iv-1) to (iv-6):

[0137] (iv-1) Average transmittance T in the wavelength range of 440 nm to 490 nm 440-490(0度)AVE It is over 90%;

[0138] (iv-2) Average transmittance T in the wavelength range of 490 nm to 560 nm 490-560(0度)AVE It is over 90%;

[0139] (iv-3) Average transmittance T in the wavelength range of 560 nm to 590 nm 560-590(0度)AVE It is over 90%;

[0140] (iv-4) The shortest wavelength IR50 with 50% transmittance in the range above 600 nm. (0度) Within the range of 630nm to 730nm;

[0141] (iv-5) Maximum transmittance T in the wavelength range of 700 nm to 760 nm 700-760(0度)MAX It is over 25%;

[0142] (iv-6) Maximum transmittance T in the wavelength range of 760 nm to 900 nm 760-900(0度)MAX It is below 2%.

[0143] Spectral characteristics of the spectral transmittance curves under an incident angle of 30 degrees (iv-7) to (iv-12):

[0144] (iv-7) Average transmittance T in the wavelength range of 440 nm to 490 nm 440-490(30度)AVE It is over 90%;

[0145] (iv-8) Average transmittance T in the wavelength range of 490 nm to 560 nm 490-560(30度)AVE It is over 90%;

[0146] (iv-9) Average transmittance T in the wavelength range of 560 nm to 590 nm 560-590(30度)AVE It is over 90%;

[0147] (iv-10) The shortest wavelength IR50 with 50% transmittance in the range above 600 nm. (30度) Within the range of 630nm to 730nm;

[0148] (iv-11) Maximum transmittance T in the wavelength range of 700 nm to 760 nm 700-760(30度)MAX It is over 25%;

[0149] (iv-12) Maximum transmittance T in the wavelength range of 760 nm to 900 nm 760-900(30度)MAX It is below 2%.

[0150] By satisfying the spectral characteristics (iv-1) to (iv-3), it indicates excellent transmittance in the visible light region.

[0151] T 440-490(0度)AVE Preferably, it is 92% or more, and more preferably 93% or more.

[0152] T 490-560(0度)AVE Preferably, it is 91% or more, and more preferably 92% or more.

[0153] T 560-590(0度)AVE Preferably, it is 92% or more, and more preferably 93% or more.

[0154] By satisfying the spectral characteristics (iv-4), it indicates that it can block infrared light and effectively absorb visible transmitted light. IR50 (0度) Preferably, it is in the range of 640nm to 720nm, and more preferably in the range of 650nm to 710nm.

[0155] By satisfying the spectral characteristics (iv-5), it is shown that light leakage (ripples) of dielectric multilayer films can be generated in the wavelength range of 700 nm to 760 nm.

[0156] T700-760(0度)MAX Preferably, it is 30% or more, and more preferably 50% or more.

[0157] By satisfying the spectral characteristics (iv-6), it indicates excellent light blocking properties in the wavelength range of 760 nm to 900 nm. 760-900(0度)MAX Preferably, it is 1.8% or less, more preferably 1.5% or less.

[0158] By satisfying the spectral characteristics (iv-7) to (iv-9), it is indicated that the transmittance in the visible light region is excellent even at high incident angles.

[0159] T 440-490(30度)AVE Preferably, it is 92% or more, and more preferably 93% or more.

[0160] T 490-560(30度)AVE Preferably, it is 92% or more, and more preferably 93% or more.

[0161] T 560-590(30度)AVE Preferably, it is 92% or more, and more preferably 93% or more.

[0162] By satisfying the spectral characteristics (iv-10), it indicates that a large amount of visible light can be absorbed even at high incident angles. IR50 (30度) Preferably, it is in the range of 640nm to 720nm, and more preferably in the range of 650nm to 710nm.

[0163] By satisfying the spectral characteristics (iv-11), it is shown that light leakage (ripple) of dielectric multilayer films can be generated even at high incident angles in the wavelength range of 700 nm to 760 nm.

[0164] T 700-760(30度)MAX Preferably, it is 30% or more, and more preferably 50% or more.

[0165] By satisfying the spectral characteristics (iv-12), it is shown that the light blocking performance is excellent even at high incident angles in the wavelength range of 760 nm to 900 nm. 760-900(30度)MAX Preferably, it is 1.8% or less, more preferably 1.5% or less.

[0166] As shown in the spectral characteristics (iv-5) above, the dielectric multilayer film of the present invention can produce light leakage (ripple) in the wavelength range of 700 nm to 760 nm at an incident angle of 0 degrees. Light in this wavelength range is absorbed by the NIR pigment of the resin film described later; therefore, even if light leakage occurs, the filter as a whole blocks light. Furthermore, the multilayer film designed to produce light leakage in the wavelength range of 700 nm to 760 nm is less prone to light leakage in the wavelength range of 800 nm to 900 nm, even at high incident angles.

[0167] On the other hand, multilayer films that do not leak light at an incident angle of 0 degrees exhibit light leakage around 800 nm at very high incident angles of approximately 70 degrees. To cover this leakage using the absorption capacity of NIR dyes, dyes with maximum absorption wavelengths above 800 nm are required. However, dyes with absorption capacity above 800 nm also absorb visible light, thus reducing the overall visible light transmittance of the filter.

[0168] The filter of the present invention is a filter that has high visible light transmittance as shown in spectral characteristics (i-1) to (i-3) and suppresses oblique incidence shift as shown in spectral characteristics (i-20) to (i-23) by combining the multilayer film of the medium and the resin film described later.

[0169] 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 a NIR reflective layer). The other dielectric multilayer film is preferably designed as an NIR reflective layer, a reflective layer having a reflective region other than the near-infrared region, or an anti-reflective layer.

[0170] A NIR reflective layer is a dielectric multilayer film designed to block light in the near-infrared region. For example, an NIR reflective layer may transmit visible light and primarily reflect light in the near-infrared region, excluding the light-blocking region of the resin film acting as an absorption layer. It should be noted that 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 also be appropriately designed to block light in wavelength ranges other than the near-infrared region, such as near-ultraviolet light, in addition to its NIR reflective properties.

[0171] The NIR reflective layer is, for example, composed of a dielectric multilayer film obtained by alternately stacking a low-refractive-index dielectric film (low-refractive-index film) and a high-refractive-index dielectric film (high-refractive-index film). The refractive index of the high-refractive-index film is preferably 1.6 or higher, more preferably 2.2 to 2.5. Examples of materials for the high-refractive-index film include Ta₂O₅, TiO₂, and Nb₂O₅. Among these, TiO₂ is preferred considering factors such as film formation properties, reproducibility of refractive index, and stability.

[0172] On the other hand, the refractive index of the low-refractive-index film is preferably less than 1.6, more preferably greater than or equal to 1.45 and less than 1.55. Examples of materials that can be used for low-refractive-index films include SiO2 and SiO2. x N y From the perspectives of film-forming reproducibility, stability, and economy, SiO2 is preferred.

[0173] To form a multilayer film that can produce light leakage (ripple) in the wavelength range of 700nm to 760nm at an incident angle of 0 degrees, one approach is to combine multiple multilayer films with different spectral characteristics when transmitting and selecting the desired wavelength band. Specifically, the reflected light can be shifted by balancing silicon dioxide and titanium dioxide, thereby adjusting to the desired light blocking wavelength band.

[0174] In the NIR reflective layer, the total number of layers of the dielectric multilayer film constituting the reflective layer is preferably 20 or more, more preferably 30 or more, and even more preferably 35 or more. However, when the total number of layers increases, warping or film thickness may occur. Therefore, the total number of layers is preferably 100 or less, more preferably 75 or less, and even more preferably 60 or less.

[0175] In addition, the overall thickness of the reflective layer is preferably 2μm to 10μm.

[0176] If the total number of layers and the thickness of the dielectric multilayer film are within the above range, the NIR reflective layer meets the requirements for miniaturization and can suppress incident angle dependence while maintaining high productivity.

[0177] In addition, vacuum film formation processes such as CVD, sputtering, and vacuum evaporation can be used in the formation of dielectric multilayer films; wet film formation processes such as spraying and immersion can also be used.

[0178] A specific spectral characteristic can be imparted using a single NIR reflective layer (a set of dielectric multilayer films), or by using two or more NIR reflective layers. When there are two or more NIR reflective layers, each reflective layer can have the same or different configurations. Typically, multiple reflective layers with different reflection bands are used. When two reflective layers are provided, one can be configured as a near-infrared reflective layer that blocks short-wavelength light in the near-infrared region, and the other can be configured as a near-infrared and near-ultraviolet reflective layer that blocks both long-wavelength light and light in the near-infrared and near-ultraviolet regions.

[0179] Examples of antireflective layers include: multilayer dielectric films, intermediate refractive index media, and moth-eye structures with gradually changing refractive index. Among these, multilayer dielectric films are preferred from the perspective of optical efficiency and productivity. Antireflective layers, like reflective layers, are obtained by alternately stacking dielectric films.

[0180] <Substrate>

[0181] In the filter of the present invention, the substrate has a resin film comprising NIR pigment (IR) and resin, as described later.

[0182] <Spectral properties of resin films>

[0183] The resin film preferably satisfies all of the following spectral characteristics (ii-1) to (ii-4).

[0184] (ii-1) In the spectral transmittance curve, the average internal transmittance T in the wavelength range of 440 nm to 490 nm 440-490AVE It is over 84%;

[0185] (ii-2) In the spectral transmittance curve, the average internal transmittance T in the wavelength range of 490 nm to 560 nm. 490-560AVE It is over 94%;

[0186] (ii-3) In the spectral transmittance curve, the average internal transmittance T in the wavelength range of 560 nm to 590 nm 560-590AVE It is over 80%;

[0187] (ii-4) In the spectral transmittance curve, the maximum internal transmittance T in the wavelength range of 700 nm to 760 nm. 700-760MAX It is below 5%.

[0188] By satisfying the spectral characteristics (ii-1) to (ii-3), it is indicated that the transmittance in the visible light region is high.

[0189] T 440-490AVE Preferably, it is 85% or more, and more preferably 86% or more.

[0190] T 490-560AVE Preferably, it is 95% or more, and more preferably 96% or more.

[0191] T 560-590AVE Preferably, it is 84% ​​or more, and more preferably 86% or more.

[0192] By satisfying the spectral characteristics (ii-4), it is indicated that it can absorb light in a wide wavelength range of 700 nm to 760 nm.

[0193] T 700-760MAX Preferably, it is 1% or less, more preferably 0.5% or less.

[0194] The resin film preferably also satisfies the following spectral characteristics (ii-5).

[0195] (ii-5) In the spectral transmittance curve, the maximum internal transmittance T in the wavelength range of 760 nm to 800 nm. 760-800MAX It is below 15%.

[0196] T 760-800MAX Preferably, it is 1% or less, more preferably 0.5% or less.

[0197] <NIR Pigment>

[0198] NIR pigments (IR) are NIR pigments that have the maximum absorption wavelength in the resin range of 680 nm to 800 nm. By containing this pigment, near-infrared light can be effectively blocked. Additionally, "resin" refers to the resin that constitutes the resin film.

[0199] For the pigment (IR), it is preferable that the spectral transmittance curve of the coated film obtained by dissolving the pigment (IR) in the resin in such a way that the transmittance at the maximum absorption wavelength is 10% satisfies all the following spectral characteristics (iii-1) to (iii-3).

[0200] (iii-1) In the spectral transmittance curve, the average internal transmittance T in the wavelength range of 440 nm to 490 nm 440-490AVE It is over 94%;

[0201] (iii-2) In the spectral transmittance curve, the average internal transmittance T in the wavelength range of 490 nm to 560 nm 490-560AVE It is over 94%;

[0202] (iii-3) In the spectral transmittance curve, the average internal transmittance T in the wavelength range of 560 nm to 590 nm 560-590AVE It is over 94%.

[0203] By satisfying the spectral characteristics (iii-1) to (iii-3), it is indicated that the transmittance in the visible light region is high.

[0204] T 440-490AVE Preferably, it is 95% or more, and more preferably 96% or more.

[0205] T 490-560AVE Preferably, it is 96% or higher, and more preferably 98% or higher.

[0206] T 560-590AVE Preferably, it is 95% or more, and more preferably 96% or more.

[0207] As an NIR pigment (IR), it can be composed of one compound or contain two or more compounds. From the viewpoint of easily satisfying the spectral characteristics (ii-4) of the above-mentioned resin film, such as absorbing light in a wide wavelength range of 700 nm to 760 nm, it is preferable to include three or more compounds in the resin that have the maximum absorption wavelength in the range of 680 nm to 800 nm, and it is particularly more preferable to include compounds selected by selecting one or more of each of compounds (A) to (C) with the following characteristics.

[0208] Compound (A): A compound in a resin that has a maximum absorption wavelength in the range of wavelengths greater than or equal to 680 nm and less than 720 nm;

[0209] Compound (B): A compound in a resin that has a maximum absorption wavelength in the range of wavelengths greater than or equal to 720 nm and less than 740 nm;

[0210] Compound (C): A compound in a resin that has the maximum absorption wavelength in the range of wavelengths above 740 nm and below 780 nm.

[0211] From the viewpoints of visible light transmittance, solubility in resin, and durability, NIR pigments are preferably derived from squaric acid. Choose from salt pigments or anthocyanin pigments.

[0212] <Square acid inner> Salt pigment >

[0213] Squamous acid Salt pigments are preferably compounds represented by formula (I) or formula (II) below.

[0214] It should be noted that within the squaric acid... When two or more identical symbols exist in a salt pigment compound, these symbols can be the same or different. The same applies to anthocyanins.

[0215] <Square acid inner> Salt compound (I) >

[0216]

[0217] The symbols in the above formula are as follows.

[0218] R 24 and R 26 Each of the following can independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group or an alkoxy group with 1 to 20 carbon atoms, an acyl group with 1 to 10 carbon atoms, an aryl group with 6 to 11 carbon atoms, an aralkyl group with 7 to 18 carbon atoms that may have substituents and may have oxygen atoms between carbon atoms, and -NR. 27 R 28 (R 27 and R 28 Each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or a -C(=O)-R group. 29 (R 29 (Hydrogen atom, halogen atom, hydroxyl group, may have substituents and may contain unsaturated bonds between carbon atoms, oxygen atom, saturated or unsaturated ring structure, hydrocarbon group with 1 to 25 carbon atoms), -NHR 30or -SO2-R 30 (R 30 Each of the above groups consists of one or more hydrogen atoms that may be substituted with halogen atoms, hydroxyl groups, carboxyl groups, sulfonyl groups, or cyano groups, and may contain unsaturated bonds, oxygen atoms, saturated or unsaturated ring structures, or hydrocarbon groups with 1 to 25 carbon atoms, or groups represented by the following formula (S) (R). 41 and R 42 Each can independently represent a hydrogen atom, a halogen atom, or an alkyl group or an alkoxy group having 1 to 10 carbon atoms. (k is 2 or 3).

[0219]

[0220] R 21 and R 22 They can connect with each other and form 5- or 6-membered heterocycles A and R together with nitrogen atoms. 22 and R 25 They can connect with each other and form 5- or 6-membered heterocycles B and R together with nitrogen atoms. 21 and R 23 They can connect with each other and form 5- or 6-membered heterocyclic C atoms together with nitrogen atoms.

[0221] As R in the case of forming heterocyclic A 21 and R 22 The bonded divalent group -Q- represents an alkylene or alkyleneoxy group, wherein the hydrogen atom of the alkylene or alkyleneoxy group may be replaced by 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 and a substituent.

[0222] As R in the case of forming heterocyclic B 22 and R 25 The bonded divalent group -X 1 -Y 1 - and R in the case of forming heterocyclic C 21 and R 23 The bonded divalent group -X 2 -Y 2 -(The side bonded to nitrogen is X) 1 and X 2 ), X 1 and X 2 Each is a group represented by formula (1x) or formula (2x) below, Y 1 and Y 2 Each is represented by a group selected from any of the following formulas (1y) to (5y). In X 1 and X 2 When each of the groups is represented by the following formula (2x), Y 1and Y 2 Each can be a single bond, and in this case, there can be oxygen atoms between carbon atoms.

[0223]

[0224] In formula (1x), each of the four Zs independently represents a hydrogen atom, a hydroxyl group, an alkyl group with 1 to 6 carbon atoms or an alkoxy group with 1 to 6 carbon atoms, or -NR. 38 R 39 (R 38 and R 39 Each can independently represent an alkyl group having 1 to 20 hydrogen 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 It represents an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms.

[0225] R 27 R 28 R 29 R 31 ~R 37 R without the formation of heterocycles 21 ~R 23 and R 25 Each can bond with any of these groups to form a 5-membered or 6-membered ring. R 31 and R 36 Direct bonding is possible, R 31 and R 37 They can be bonded directly.

[0226] R without heterocyclic formation 21 R 22 R 23 and R 25 Each of the following can be independently represented as a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group having 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbon atoms, an acyloxy group having 1 to 10 carbon atoms, an aryl group having 6 to 11 carbon atoms, or an aralkyl group having 7 to 18 carbon atoms that may have substituents and may have oxygen atoms between carbon atoms.

[0227] As for compound (I), for example, compounds represented by any of formulas (I-1) to (I-3) can be listed. From the viewpoints of solubility in resin, heat resistance and light resistance in resin, and visible light transmittance of the resin layer containing the compound, the compound represented by formula (I-1) is particularly preferred.

[0228]

[0229] The symbols in equations (I-1) to (I-3) are defined in the same way as the same symbols in equation (I), and the preferred methods are also the same.

[0230] In compound (I-1), as X 1 Preferred group (2x) is used as Y. 1 Preferably, a single bond or a group (1y). In this case, as R 31 ~R 36 Preferably, it is an alkyl group having 1 to 3 hydrogen atoms, more preferably a hydrogen atom or a methyl group. It should be noted that, as -Y 1 -X 1 Specifically, divalent organic groups represented by formulas (11-1) to (12-3) can be listed.

[0231] -C(CH3)2-CH(CH3)-……(11-1)

[0232] -C(CH3)2-CH2-……(11-2)

[0233] -C(CH3)2-CH(C2H5)-……(11-3)

[0234] -C(CH3)2-C(CH3)(nC3H7)-……(11-4)

[0235] -C(CH3)2-CH2-CH2-……(12-1)

[0236] -C(CH3)2-CH2-CH(CH3)-……(12-2)

[0237] -C(CH3)2-CH(CH3)-CH2-……(12-3)

[0238] Furthermore, in compound (I-1), considering the steepness of the change near the boundary between the visible and near-infrared regions in the spectral transmittance curve, R... 21 More preferably, it is a group represented by formula (4-1) or formula (4-2).

[0239]

[0240] In equations (4-1) and (4-2), R 71 ~R 75 Independently represents an alkyl group having 1 to 4 hydrogen atoms, halogen atoms, or carbon atoms.

[0241] In compound (I-1), R 24 Preferred is -NR 27 R28 As -NR 27 R 28 From the viewpoint of solubility in resins and coating solvents, -NH-C(=O)-R is preferred. 29 or -NH-SO2-R 30 .

[0242] In compound (I-1) R 24 -NH-C(=O)-R 29 The compound is shown in formula (I-11).

[0243]

[0244] R 23 and R 26 The atom is preferably a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and more preferably all of them are hydrogen atoms.

[0245] As R 29 Preferably, the substituent is an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an aralkyl group having 7 to 18 carbon atoms and having an oxygen atom between the carbon atoms. Examples of substituents include: hydroxyl, carboxyl, sulfonyl, cyano, alkyl group having 1 to 6 carbon atoms, fluoroalkyl group having 1 to 6 carbon atoms, alkoxy group having 1 to 6 carbon atoms, and acyloxy group having 1 to 6 carbon atoms.

[0246] As R 29 Preferably, the group is selected from alkyl groups with 1 to 17 carbon atoms that are straight-chain, branched, or cyclic, phenyl groups that can be substituted by alkoxy groups with 1 to 6 carbon atoms, and aralkyl groups with 7 to 18 carbon atoms that can have oxygen atoms between carbon atoms.

[0247] As R 29 Alternatively, the following groups can be used independently: the group is a hydrocarbon group with 5 to 25 carbon atoms that has one or more hydrogen atoms that can be replaced by hydroxyl, carboxyl, sulfonyl or cyano groups and can contain unsaturated bonds, oxygen atoms, saturated or unsaturated ring structures between carbon atoms, and has at least one branched chain.

[0248] As compound (I-11), more specifically, the compounds shown in the table below can be listed. Additionally, the compounds shown in the table below are in squaric acid. The symbols on the left and right sides of the salt skeleton have the same meaning.

[0249] [Table 1]

[0250]

[0251] Of the compounds (I-11), compounds (I-11-1) to (I-11-12) are preferred from the viewpoints of visible light transmittance, solubility in resin, and durability. Of these, compounds (I-11-1) to (I-11-4) are further preferred from the viewpoints of solubility in resin and durability.

[0252] In compound (I-1) R 24 -NH-SO2-R 30 The compound is shown in formula (I-12).

[0253]

[0254] R 23 and R 26 The atom is preferably a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and more preferably all of them are hydrogen atoms.

[0255] From the perspective of lightfastness, R 30 Independently preferred are alkyl groups having 1 to 12 branched carbon atoms, alkoxy groups having 1 to 12 branched carbon atoms, or hydrocarbon groups having 6 to 16 carbon atoms with an unsaturated ring structure. Examples of unsaturated ring structures include: benzene, toluene, xylene, furan, benzofuran, etc. 30 More preferably, it is an alkyl group having 1 to 12 branched carbon atoms or an alkoxy group having 1 to 12 branched carbon atoms. It should be noted that, in the representation of R... 30 In each of the groups, some or all of the hydrogen atoms can be replaced by halogen atoms, especially fluorine atoms.

[0256] As compound (I-12), more specifically, the compounds shown in the table below can be listed. Additionally, the compounds shown in the table below are in squaric acid. The symbols on the left and right sides of the salt skeleton have the same meaning.

[0257] [Table 2]

[0258]

[0259] Of the compounds (I-12), compounds (I-12-1) to (I-12-8) and (I-12-13) to (I-12-20) are preferred from the viewpoints of visible light transmittance, solubility in resin, and durability. Of these, compounds (I-12-1) to (I-12-5) are further preferred from the viewpoints of solubility in resin and durability.

[0260] <Square acid inner> Salt compound (II) >

[0261]

[0262] The symbols in the above formula are as follows.

[0263] Each ring Z is independently a 5-membered or 6-membered ring with 0 to 3 heteroatoms, and the hydrogen atoms in ring Z can be substituted.

[0264] R 1 and R 2 They can connect with each other and form heterocycles A1,R together with nitrogen atoms. 2 and R 3 They can connect with each other and form heterocycles B1 and R together with nitrogen atoms. 1 The carbon atoms or heteroatoms constituting ring Z can connect with each other and form a heterocycle C1 together with a nitrogen atom. In this case, the hydrogen atoms in heterocycles A1, B1, and C1 can be substituted. R without heterocycle formation... 1 and R 2 Each can independently represent a hydrogen atom, a halogen atom, or a hydrocarbon group, which may contain unsaturated bonds, heteroatoms, saturated or unsaturated ring structures between carbon atoms, and may have substituents. R 4 And R in the case of no heterocycle formation 3 Each of these can independently represent a hydrogen atom, a halogen atom, or an alkyl or alkoxy group, wherein each alkyl or alkoxy group may contain heteroatoms between carbon atoms and may have substituents.

[0265] As for compound (II), for example, compounds represented by any of formulas (II-1) to (II-3) can be listed. From the viewpoint of solubility in resin and visible light transmittance in resin, compounds represented by formula (II-3) are particularly preferred.

[0266]

[0267] In equations (II-1) and (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 that may have substituents; R 3 ~R 6 Each can independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms that may have substituents.

[0268] In equation (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 that may have substituents; R 7 and R 8 Each can independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 5 carbon atoms that may have substituents.

[0269] Considering factors such as solubility in resins and visible light transmittance, R in compounds (II-1) and (II-2) 1 and R 2 Alkyl groups having 1 to 15 carbon atoms are preferred, alkyl groups having 7 to 15 carbon atoms are more preferred, and R is even more preferred. 1 and R 2 At least one of them is a branched alkyl group having 7 to 15 carbon atoms, with R being particularly preferred. 1 and R 2 Both are branched alkyl groups with 8 to 15 carbon atoms.

[0270] Considering factors such as solubility in transparent resins and visible light transmittance, R in compound (II-3) 1 Alkyl groups having 1 to 15 carbon atoms are preferred, more preferably alkyl groups having 1 to 10 carbon atoms, and particularly preferably ethyl or isopropyl.

[0271] From the perspectives of visible light transmittance and ease of synthesis, R 4 The preferred atoms are hydrogen atoms or halogen atoms, with hydrogen atoms being particularly preferred.

[0272] R 7 and R 8 The preferred components are hydrogen atoms, halogen atoms, and alkyl groups having 1 to 5 carbon atoms that can be replaced by halogen atoms; more preferably, hydrogen atoms, halogen atoms, and methyl groups.

[0273] R 9 ~R 12 The preferred components are hydrogen atoms, halogen atoms, and alkyl groups having 1 to 5 carbon atoms that can be replaced by halogen atoms.

[0274] As -CR 9 R 10 -CR 11 R 12 - Examples of divalent organic groups represented by the following groups (13-1) to (13-5) can be listed.

[0275] -CH(CH3)-C(CH3)2-……(13-1)

[0276] -C(CH3)2-CH(CH3)-……(13-2)

[0277] -C(CH3)2-CH2-……(13-3)

[0278] -C(CH3)2-CH(C2H5)-……(13-4)

[0279] -CH(CH3)-C(CH3)(CH2-CH(CH3)2)-……(13-5)

[0280] As compounds (II-3), more specifically, the compounds shown in the table below can be listed. Additionally, the compounds shown in the table below are in squaric acid. The symbols on the left and right sides of the salt skeleton have the same meaning.

[0281] [Table 3]

[0282]

[0283] Of the compounds (II-3), compounds (II-3-1) to (II-3-4) are preferred from the viewpoints of visible light transmittance, solubility in resin, and durability. Of these, compound (II-3-2) is further preferred from the viewpoint of solubility in resin.

[0284] Compounds (I) through (II) can each be manufactured by known methods. Compound (I) can be manufactured 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. Compound (II) can be manufactured by the method described in International Publication No. 2017 / 135359.

[0285] <Anthocyanins>

[0286] Anthocyanins are preferably compounds represented by formula (III).

[0287] <Anthocyanin compound (III)>

[0288]

[0289] The symbols in the above formula are as follows.

[0290] R 101 ~R 109 Each can independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 15 carbon atoms that may have substituents, or an aryl group having 5 to 20 carbon atoms that may have substituents. R 110 ~R 114Each can be independently represented by a hydrogen atom, a halogen atom, or an alkyl group having 1 to 15 carbon atoms.

[0291] X - It represents a monovalent anion.

[0292] n1 is either 0 or 1. (This is related to the inclusion of -(CH2)) n1 The hydrogen atom bonded to the carbon ring can be replaced by a halogen atom, an alkyl group having 1 to 15 carbon atoms that can have a substituent, or an aryl group having 5 to 20 carbon atoms that can have a substituent.

[0293] In the above, alkyl groups (including those with alkoxy groups) can be straight-chain, branched, or saturated ring structures. Aryl groups are groups bonded via carbon atoms of aromatic rings such as benzene, naphthyl, biphenyl, furan, thiophene, and pyrrole rings that constitute aromatic compounds. Examples of substituents that can be alkyl groups with 1 to 15 carbon atoms, alkoxy groups with 1 to 15 carbon atoms, or aryl groups with 5 to 20 carbon atoms include halogen atoms and alkoxy groups with 1 to 10 carbon atoms.

[0294] In equation (III), R 101 Preferably, it is an alkyl group having 1 to 15 carbon atoms or an aryl group having 5 to 20 carbon atoms. From the viewpoint of maintaining high visible light transmittance in the resin, it is more preferably an alkyl group having 1 to 15 carbon atoms with a branched chain.

[0295] In equation (III), R 102 ~R 105 R 108 and R 109 Each atom is preferably a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, an alkoxy group having 1 to 15 carbon atoms, or an aryl group having 5 to 20 carbon atoms. From the viewpoint of obtaining high visible light transmittance, a hydrogen atom is more preferred.

[0296] In equation (III), R 110 ~R 114 Each of the components is preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms, and from the viewpoint of obtaining high visible light transmittance, a hydrogen atom is more preferred.

[0297] R 106 and R 107 Each of the following 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 straight-chain, cyclic, or branched alkyl groups), and more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. Additionally, R 106 and R 107 Preferably, they are the same group.

[0298] As X - Examples include: I - BF4 - PF6 - ClO4 - Anions represented by formulas (X1) and (X2), preferably BF4. - or PF6 - .

[0299]

[0300] In the following description, pigment (III) excluding R 101 ~R 114 The parts other than that are also called the skeleton (III).

[0301] Compounds in formula (III) with n1 = 1 are shown in formula (III-1), and compounds in formula (III) with n1 = 0 are shown in formula (III-2).

[0302]

[0303] In equations (III-1) and (III-2), R 101 ~R 114 and X - The same applies as in equation (III). R 115 ~R 120 Each can independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 15 carbon atoms that may have substituents, an alkoxy group having 1 to 15 carbon atoms that may have substituents, or an aryl group having 5 to 20 carbon atoms that may have substituents. R 115 ~R 120 Each of the following 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 straight-chain, cyclic, or branched alkyl groups), and more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms. Additionally, R 115 ~R 120 Preferably, they are the same group.

[0304] As a compound represented by formula (III), a compound represented by formula (III-1) is particularly preferred.

[0305] As compounds represented by formula (III-1), more specifically, compounds in which the atoms or groups bonded to each skeleton are respectively represented by the atoms or groups shown in the table below. In all the compounds shown in the table below, R 101 ~R 109 The left and right sides of the expression are identical.

[0306] R in the table below 110 -R 114 The atom or group bonded to the central benzene ring in each formula is represented by "H" when all five atoms are hydrogen atoms. In R... 110 -R 114 If any one of the elements is a substituent and the others are hydrogen atoms, only the symbol for the substituent and the combination of the substituents are recorded. For example, "R 112 The description of "-C(CH3)3" indicates R 112 It is -C(CH3)3 and otherwise consists of hydrogen atoms.

[0307] R in Table 4 115 -R 120 The atom or group bonded to the central cyclohexane ring in formula (III-1) is represented by "H" if all six atoms are hydrogen atoms. In R 115 -R 120 If any one of them is a substituent and the others are hydrogen atoms, only the symbol of the substituent and the combination of the substituent are recorded.

[0308] [Table 4]

[0309]

[0310] Of the compounds (III-1), compounds (III-1-1) to (III-1-12) are preferred from the viewpoints of visible light transmittance, solubility in resin, and durability. Of these, compounds (III-1-2), (III-1-6), and (III-1-9) are more preferred from the viewpoints of visible light transmittance and durability.

[0311] Pigment (III) can be manufactured, for example, by the methods described in Dyes and pigments 73 (2007) 344-352 and J. Heterocyclic chem, 42, 959 (2005).

[0312] The content of NIR pigment (IR) in the resin film is preferably 0.1 to 25 parts by mass relative to 100 parts by mass of resin, more preferably 0.3 to 15 parts by mass. It should be noted that when two or more compounds are combined, the above content refers to the sum of all compounds.

[0313] Furthermore, when the NIR pigment (IR) contains compounds (A) to (C), the content of compound (A) is preferably 0.5 to 5 parts by mass relative to 100 parts by mass of resin, the content of compound (B) is preferably 0.5 to 5 parts by mass, and the content of compound (C) is preferably 0.5 to 5 parts by mass.

[0314] <UV Pigment>

[0315] The pigment (U) is a UV pigment that has the maximum absorption wavelength in the resin in the range of 370 nm to 430 nm. By containing this pigment, ultraviolet light can be effectively blocked.

[0316] As pigments (U), the following can be listed: Azole pigments, anthocyanins, naphthalene dicarboximide pigments, diazole pigments, Azine pigment, Pigments include azole alkyl pigments, naphthalene dicarboxylic acid pigments, styrene pigments, anthracene pigments, cyclic carbonyl pigments, and triazole pigments. Among these, anthocyanin pigments are particularly preferred. Furthermore, pigments (U) can be used alone or in combination with two or more.

[0317] As a pigment (U), anthocyanin pigment represented by the following formula (M) is particularly preferred.

[0318]

[0319] The symbols in equation (M) are as follows.

[0320] R 1 It indicates a monovalent hydrocarbon group with 1 to 12 carbon atoms that can have substituents.

[0321] As substituents, alkoxy, acyl, acyloxy, cyano, dialkylamino, or chlorine atoms are preferred. The number of carbon atoms in the aforementioned alkoxy, acyl, acyloxy, and dialkylamino groups is preferably 1 to 6.

[0322] R as a non-substituent 1 Specifically, preferably, alkyl groups having 1 to 12 carbon atoms in which a portion of the hydrogen atom can be replaced by an aliphatic ring, an aromatic ring, or an alkenyl group; cycloalkyl groups having 3 to 8 carbon atoms in which a portion of the hydrogen atom can be replaced by an aromatic ring, an alkyl group, or an alkenyl group; and aryl groups having 6 to 12 carbon atoms in which a portion of the hydrogen atom can be replaced by an aliphatic ring, an alkyl group, or an alkenyl group.

[0323] In R 1 When the alkyl group is unsubstituted, it can be straight-chain or branched, and more preferably has 1 to 6 carbon atoms.

[0324] In R 1When the alkyl group having 1 to 12 carbon atoms in which a portion of the hydrogen atom is replaced by an aliphatic ring, aromatic ring, or alkenyl group is present, it is more preferred to have 1 to 4 carbon atoms in a cycloalkyl group having 3 to 6 carbon atoms, or alkyl groups having 1 to 4 carbon atoms replaced by a phenyl group. Alkyl groups having 1 or 2 carbon atoms replaced by a phenyl group are particularly preferred. It should be noted that alkenyl-substituted alkyl groups refer to alkyl groups that, although entirely alkenyl, do not have unsaturated bonds between the 1 and 2 positions, such as allyl or 3-butenyl.

[0325] Preferred R 1 An alkyl group having 1 to 6 carbon atoms, in which a portion of a hydrogen atom can be replaced by a cycloalkyl or phenyl group. Particularly preferred is R. 1 Alkyl groups having 1 to 6 carbon atoms, specifically including: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, etc.

[0326] R 2 ~R 5 Each of the following can be independently represented: 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 and alkoxy groups preferably have 1 to 6 carbon atoms, more preferably 1 to 4.

[0327] R 2 and R 3 Preferably, at least one of them is an alkyl group, and more preferably, all of them are alkyl groups. In R 2 and R 3 In the absence of an alkyl group, a hydrogen atom is more preferred. 2 and R 3 Alkyl groups having 1 to 6 carbon atoms are particularly preferred.

[0328] R 4 and R 5 Preferably, at least one of them is a hydrogen atom, more preferably, all of them are hydrogen atoms. In R 4 and R 5 In the absence of hydrogen atoms, alkyl groups with 1 to 6 carbon atoms are preferred.

[0329] Y indicates that R 6 and R 7 Substituted methylene or oxygen atom.

[0330] R 6 and R 7 Each can be independently represented by 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.

[0331] X represents any one of the divalent groups represented by the following formulas (X1) to (X5).

[0332]

[0333] R 8 and R 9 Each can independently represent a monovalent hydrocarbon group with 1 to 12 carbon atoms that can have substituents, R 10 ~R 19 Each can independently represent a hydrogen atom or a monovalent hydrocarbon group with 1 to 12 carbon atoms that may have substituents.

[0334] As R 8 ~R 19 Substituents, such as those with R, can be listed. 1 Substituents with the same substituents in R are preferred in the same way. 8 ~R 19 In the case of a hydrocarbon group without substituents, examples of R groups without substituents can be listed. 1 The same method.

[0335] In equation (X1), R 8 and R 9 Different groups can be used, but the same group is preferred. In R 8 and R 9 When the alkyl group is unsubstituted, it can be linear or branched, and the number of carbon atoms is more preferably 1 to 6.

[0336] Preferred R 8 and R 9 All are alkyl groups having 1 to 6 carbon atoms, in which a hydrogen atom can be substituted by a cycloalkyl or phenyl group. Particularly preferred are R... 8 and R 9 All of them are alkyl groups with 1 to 6 carbon atoms. Specifically, examples include: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, etc.

[0337] In equation (X2), R 10 and R 11 More preferably, they are alkyl groups having 1 to 6 carbon atoms, R 10 and R 11 The same alkyl group is particularly preferred.

[0338] In equation (X3), R 12 and R 15 Preferably, the alkyl group consists of 1 to 6 carbon atoms, either all of which are hydrogen atoms or without substituents. R is one of two groups bonded to the same carbon atom. 13 and R 14 Preferably, all of them are hydrogen atoms or are alkyl groups having 1 to 6 carbon atoms.

[0339] In formula (X4), two groups R bonded to the same carbon atom 16 and R17 and R 18 and R 19 Preferably, all of them are hydrogen atoms or are alkyl groups having 1 to 6 carbon atoms.

[0340] Compound (M) can be manufactured using known methods.

[0341] The UV pigment (U) content in the resin film is preferably 0.1 to 15 parts by weight, more preferably 1 to 10 parts by weight, relative to 100 parts by weight of the resin. Within this range, it is less likely to lead to a decrease in the resin properties.

[0342] <Base Material Composition>

[0343] The substrate in this filter can be a single-layer structure or a multi-layer structure. Furthermore, the material used as the substrate can be any transparent material that transmits visible light in the range of 400nm to 700nm; it can be organic or inorganic, without any particular restrictions.

[0344] When the substrate has a single-layer structure, a resin substrate composed of a resin film containing resin and NIR pigment (IR) is preferred.

[0345] When the substrate has a multilayer structure, it is preferable to have a composite substrate containing a resin film of NIR pigment (IR) laminated on at least one main surface of the support. In this case, the support preferably comprises a transparent resin or a transparent inorganic material.

[0346] There are no restrictions on the type of resin used, as long as it is transparent. One or more transparent resins selected from polyester resins, acrylic resins, epoxy resins, olefin-thiol resins, polycarbonate resins, polyether resins, polyaryl ester resins, polysulfone resins, polyethersulfone resins, poly(p-phenylene) resins, polyaryl ether phosphine oxide resins, polyamide resins, polyimide resins, polyamide-imide resins, polyolefin resins, cyclic olefin resins, polyurethane resins, and polystyrene resins can be used. These resins can be used alone or in combination of two or more.

[0347] From the viewpoints of the spectral characteristics, glass transition temperature (Tg), and adhesion of the resin film, it is preferable to select one or more resins selected from polyimide resin, polycarbonate resin, polyester resin, and acrylic resin.

[0348] When using multiple compounds as NIR pigments (IR) or other pigments, these compounds can be contained in the same resin film or in different resin films.

[0349] As a transparent inorganic material, glass and crystalline materials are preferred.

[0350] Examples of glasses that can be used as supports include: absorbing glasses containing copper ions (near-infrared absorbing glasses) such as fluorophosphate glasses and phosphate glasses, soda-lime glass, borosilicate glass, alkali-free glass, and quartz glass.

[0351] From the viewpoint of being able to absorb infrared light (especially 900nm to 1200nm), phosphate glasses and fluorophosphate glasses are preferred as glass. It should be noted that "phosphate glasses" also include silicate phosphate glasses in which a portion of the glass skeleton is composed of SiO2.

[0352] As a glass, chemically strengthened glass can also be obtained by exchanging alkali metal ions with small ionic radii (e.g., Li ions, Na ions) present on the main surface of the glass plate with alkali metal ions with larger ionic radii (e.g., Na ions or K ions for Li ions, and K ions for Na ions) through ion exchange at temperatures below the glass transition temperature.

[0353] Examples of crystalline materials that can be used as supports include: quartz, lithium niobate, sapphire, and other birefringent crystals.

[0354] As a support, inorganic materials are preferred from the perspective of shape stability related to long-term reliability of optical and mechanical properties, and from the perspective of manufacturability during filter manufacturing. Glass and sapphire are particularly preferred.

[0355] The resin film can be formed by dissolving or dispersing a pigment (IR), resin, or resin raw material components, and other components as needed, in a solvent to prepare a coating solution; applying the coating solution to a support and drying it; and further curing it as needed. The support can be a support included in this filter, or a peelable support used only during the formation of the resin film. Furthermore, the solvent can be any dispersion medium that can be stably dispersed or a solvent that can dissolve the resin.

[0356] In addition, the coating liquid may contain surfactants to improve voids caused by tiny air bubbles, depressions caused by the adhesion of foreign matter, and pinholes during the drying process. Furthermore, methods such as dip coating, cast coating, or spin coating can be used when applying the coating liquid. The coating liquid is applied to a support and then dried to form a resin film. If the coating liquid contains a transparent resin component, further curing treatments such as thermosetting or photocuring are performed.

[0357] Furthermore, resin films can also be manufactured into a film shape through extrusion molding. When the substrate is a single-layer structure (resin substrate) consisting of a resin film containing pigment (IR), the resin film can be used directly as the substrate. When the substrate is a multilayer structure (composite substrate) having a support and a resin film containing pigment (IR) laminated on at least one main surface of the support, the substrate can be manufactured by laminating the film onto the support and integrating it using methods such as hot pressing.

[0358] A filter may contain one layer of resin film or two or more layers of resin film. When there are two or more layers of resin film, each layer may have the same composition or different compositions.

[0359] When the substrate is a single-layer structure (resin substrate) composed of a resin film containing pigment (IR), the thickness of the resin film is preferably 20 μm to 150 μm.

[0360] When the substrate is a multilayer structure (composite substrate) having a support and a pigment-containing (IR) resin film laminated on at least one main surface of the support, the thickness of the resin film is preferably 0.3 μm to 20 μm. It should be noted that when the filter has two or more resin films, the total thickness of each resin film is preferably within the above range.

[0361] There are no particular restrictions on the shape of the substrate; it can be in the form of blocks, plates, or films.

[0362] Furthermore, from the viewpoint of reducing warpage during the formation of a dielectric multilayer film and lowering the height of the optical element, the thickness of the substrate is preferably 300 μm or less. When the substrate is a resin substrate composed of a resin film, the thickness of the substrate is preferably 50 μm to 300 μm. When the substrate is a composite substrate having a support and a resin film, the thickness of the substrate is preferably 50 μm to 300 μm.

[0363] This filter can have other constituent elements such as inorganic particles that generate absorption by controlling the transmission and absorption of light within a specific wavelength range. Specific examples of inorganic particles include: ITO (indium tin oxide), ATO (antimony-doped tin oxide), cesium tungstate, and lanthanum boride. ITO particles and cesium tungstate particles have high visible light transmittance and light absorption over a wide range of infrared wavelengths greater than 1200 nm, thus they can be used when infrared light blocking is required.

[0364] Example

[0365] Next, the invention will be described in more detail through examples.

[0366] The ultraviolet-visible spectrophotometer (UH-4150 model manufactured by Hitachi High Technology Co., Ltd.) was used to measure the various spectral characteristics.

[0367] It should be noted that the spectral characteristics without a specified incident angle are values ​​measured at an incident angle of 0 degrees (perpendicular to the main surface of the filter).

[0368] The pigments used in each example are described below.

[0369] Compound 1 (squamous acid) Salt pigment): synthesized based on U.S. Patent No. 5,543,086.

[0370] Compound 2 (squamous acid) (Hydrogen pigment): Based on International Publication No. 2017 / 135359.

[0371] Compound 3 (anthocyanin): synthesized based on Dyes and pigments 73 (2007) 344-352.

[0372] Compound 4 (anthocyanin): synthesized based on Dyes and pigments 73 (2007) 344-352.

[0373] Compound 5 (diammonium pigment): synthesized based on Japanese Patent Application Publication No. 2014-25016.

[0374] Compound 6 (squamous acid) (Hydrogen pigment): Based on International Publication No. 2019 / 230660.

[0375] Compound 7 (partial cyanide compound): synthesized with reference to Japanese Patent No. 6504176.

[0376] Compound 8 (partial cyanide compound): synthesized with reference to Japanese Patent No. 6504176.

[0377] Compound 9 (squamous acid) Salt pigment): synthesized based on U.S. Patent Application Publication No. 2014 / 0061505 and International Publication No. 2014 / 088063.

[0378] Compound 10 (anthocyanin): synthesized based on Dyes and pigments 73 (2007) 344-352.

[0379] Compound 1

[0380] Compound 2

[0381] Compound 3

[0382] Compound 4

[0383] Compound 5

[0384] Compound 6

[0385] Compound 7

[0386] Compound 8

[0387] Compound 9

[0388] Compound 10

[0389] <Spectral properties of pigments>

[0390] The 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.

[0391] Each pigment compound was added to the polyimide resin solution prepared above, with 7.5 parts by mass of each pigment compound shown in the table below relative to 100 parts by mass of resin. The solution was heated at 50°C and stirred for 2 hours. The pigment-containing resin solution was then coated onto a glass substrate (alkali glass, Schott AG D263) using a spin coater and dried to obtain a resin film (coated film) with a thickness of 2 μm.

[0392] The transmission and reflectance spectra of the resin film were measured using a spectrophotometer at an incident angle of 5 degrees within the wavelength range of 350 nm to 1200 nm. The internal transmittance curve of the spectrum was calculated using the obtained spectral transmittance and reflectance curves, and normalized to a level that makes the transmittance at the maximum absorption wavelength 10%.

[0393] The spectral characteristics are shown in the table below.

[0394] [Table 5]

[0395]

[0396] <Examples 1-1 to 1-12: Spectral Characteristics of Resin Films>

[0397] The 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.

[0398] Each compound was added to the polyimide resin solution prepared above in the manner specified in the table below, relative to 100 parts by mass of resin. The solution was heated at 50°C and stirred for 2 hours. The pigment-containing resin solution was then coated onto a glass substrate (alkali glass, Schott AG D263) using a spin coater and dried to obtain a resin film (coated film) with a thickness of 2 μm.

[0399] The transmission and reflection spectra of the resin film were measured using a spectrophotometer in the wavelength range of 350 nm to 1200 nm at an incident angle of 5 degrees.

[0400] The spectral characteristics are shown in the table below.

[0401] It should be noted that Examples 1-1 to 1-12 are for reference only.

[0402]

[0403] Resin films from Examples 1-3, 1-5, 1-11, and 1-12, which used three NIR dyes with maximum absorption wavelengths in the range of 680 nm to 800 nm in a balanced manner, yielded excellent transmittance in the visible light region and excellent light blocking properties in the range of 700 nm to 760 nm. It can be said that, in order to block light in the 700 nm to 760 nm range over a wide range while maintaining transmittance in the visible light region, it is preferable to use three or more NIR dyes with maximum absorption wavelengths in the range of 680 nm to 800 nm in a balanced manner.

[0404] The visible light transmittance of the resin films in Examples 1-7, 1-8, 1-9, and 1-10, which used two NIR dyes with a maximum absorption wavelength in the range of 680 nm to 800 nm and one NIR dye with a maximum absorption wavelength above 800 nm, was reduced.

[0405] The resin films of Examples 1-6, which increased the amount of NIR pigment added in order to achieve light blocking properties using only one NIR pigment, showed reduced transmittance in the visible light region.

[0406] <Examples 2-1 to 2-2: Spectral Characteristics of Dielectric Multilayer Films>

[0407] A reflective layer comprising a dielectric multilayer film 1 or 2 obtained by alternately stacking TiO2 and SiO2 films was designed. The number of layers, thickness, and spectral characteristics are shown in the table below.

[0408] In addition, the spectral transmittance curves of dielectric multilayer film 1 and dielectric multilayer film 2 are shown in the figure. Figure 5 and Figure 6 middle.

[0409] It should be noted that Examples 2-1 and 2-2 are for reference only.

[0410] [Table 7]

[0411]

[0412] <Example 3-1: Spectral Characteristics of a Filter>

[0413] A filter is obtained by sequentially stacking a dielectric multilayer film 1 prepared in Example 2-1, a glass substrate (alkali glass, D263 manufactured by Schott AG), a resin film from Example 1-1, and a 7-layer antireflection film obtained by alternating evaporation of SiO2 and TiO2.

[0414] The transmission spectra of the obtained filters were measured using a spectrophotometer at incident directions of 0°, 30°, and 70°.

[0415] To evaluate glare and ghosting, the filter on the sensor of a commercially available digital camera (Sony CyberShot DSC-HX5 manufactured by Sony Corporation) was removed and replaced with the filter made in Example 3-1. A white light source (tungsten-based halogen light source) was passed through a bandpass filter (750nm±20nm, 800nm±20nm, 850nm±20nm, 900nm±5nm), and an image was taken at a shutter speed of 15 seconds. The presence of glare or ghosting was visually confirmed. Additionally, the bandpass filter was removed, and a white light (total light) image was taken at a shutter speed of 0.25 seconds. The presence of glare or ghosting was visually confirmed.

[0416] The situation where glare or ghosting is not visually confirmed is rated as A, the situation where glare or ghosting is visually confirmed is rated as B, and the situation where glare or ghosting is particularly strongly observed in the situation where glare or ghosting is confirmed is rated as C.

[0417] <Example 3-2~Example 3-11>

[0418] Except for changing the resin membrane to the resin membrane shown in the table below, the filter was obtained in the same manner as in Example 3-1.

[0419] <Example 3-12>

[0420] A filter was obtained in the same manner as in Example 3-1, except that a fluorophosphate glass (manufactured by AGC Corporation, NF50T) was used as the glass substrate and the resin film was changed to the resin film shown in the table below.

[0421] <Example 3-13>

[0422] The filter was obtained in the same manner as in Example 3-1, except that the dielectric multilayer film 2 prepared in Example 2-2 was used instead of the dielectric multilayer film 1.

[0423] The results of the spectral characteristics and evaluation of glare and ghosting are shown in the table below.

[0424] In addition, the spectral transmittance curves of the filters in Example 3-11 and Example 3-13 are shown respectively. Figure 7 and Figure 8 middle.

[0425] It should be noted that Examples 3-3, 3-5, 3-11, and 3-12 are examples, while Examples 3-1, 3-2, 3-4, 3-6 to 3-10 and 3-13 are comparative examples.

[0426]

[0427] The results above show that the filters of Examples 3-3, 3-5, 3-11, and 3-12 did not leak light even at high incident angles in the 700nm–900nm range, and exhibited high transmittance in the visible light region. Furthermore, they suppressed glare and ghosting.

[0428] The filters in Examples 3-1, 3-2, 3-4, 3-7 to 3-10 showed low light blocking properties in the wavelength range of 700 nm to 760 nm.

[0429] The filter in Example 3-6 resulted in low visible light transmittance.

[0430] The filter in Example 3-13 has low light blocking properties in the wavelength range of 700nm to 900nm. In addition, at a high incident angle of 70 degrees, light leakage occurs in the wavelength range of 760nm to 900nm, and glare and ghosting are confirmed.

[0431] Although the present invention has been described in detail and with reference to specific embodiments, various changes or modifications can be made without departing from the spirit and scope of the invention, as will be apparent to those skilled in the art. This application is based on Japanese Patent Application No. 2020-176883, filed on October 21, 2020, the contents of which are incorporated herein by reference.

[0432] Industrial practicality

[0433] The filter of this invention exhibits excellent visible light transmittance and good near-infrared light blocking properties, suppressing the reduction in near-infrared light blocking at high incident angles. It is useful in applications where high-performance information acquisition devices, such as cameras or webcams for transport aircraft and sensors, are increasingly being developed.

[0434] Label Explanation

[0435] 1A, 1B, 1C, 1D... Filters, 10... Substrate, 11... Support, 12... Resin film, 30... Dielectric multilayer film.

Claims

1. A filter having a substrate and a dielectric multilayer film, the dielectric multilayer film being stacked on at least one major surface side of the substrate and serving as the outermost layer, wherein, The substrate has a resin film comprising a pigment (IR) and a resin. The pigment (IR) has a maximum absorption wavelength in the resin in the range of 680 nm to 800 nm. The pigment (IR) comprises compounds selected by choosing one or more from each of compounds (A), (B), and (C). The compound (A) has a maximum absorption wavelength in the resin in the range of wavelengths greater than or equal to 680 nm and less than 720 nm; The compound (B) has a maximum absorption wavelength in the resin in the range of wavelengths greater than or equal to 720 nm and less than 740 nm; The compound (C) has a maximum absorption wavelength in the resin in the range of wavelengths above 740 nm and below 780 nm. The pigment (IR) is selected from squaric acid. Salt pigments or anthocyanins, and The filter satisfies all of the following spectral characteristics (i-1) to (i-23): Spectral characteristics (i-1) to (i-9) in the spectral transmittance curve under the condition of 0 degrees incident angle: (i-1) an average transmittance T in the range of wavelengths from 440 nm to 490 nm 440-490(0度)AVE is 85% or more; (i-2) average transmittance T in the range of wavelengths from 490 nm to 560 nm 490-560(0度)AVE is 90% or more; (i-3) an average transmittance T in the range of wavelengths from 560 nm to 590 nm 560-590(0度)AVE is 83% or more; (i-4) wavelength at 50% transmittance IR50 (0度) in the range of 600 nm to 680 nm; (i-5) a maximum transmittance T in the range of wavelengths from 700 nm to 760 nm 700-760(0度)MAX is 2% or less; (i-6) Transmittance T at a wavelength of 750 nm 750(0度) Below 0.5%; (i-7) maximum transmittance T in the range of wavelengths from 760 nm to 800 nm 760-800(0度)MAX is 1% or less; (i-8) maximum transmittance T in the range of wavelengths from 800 nm to 900 nm 800-900(0度)MAX is 1% or less; (i-9) a maximum transmittance T in the range of wavelengths from 900 nm to 1100 nm 900-1100(0度)MAX is 1% or less; Spectral characteristics (i-10) to (i-18) in the spectral transmittance curve under the condition of an incident angle of 30 degrees: (i-10) an average transmission T in the range of wavelengths from 440 nm to 490 nm of at least 70% 440-490(30度)AVE is 84% or more; (i-11) an average transmittance T in the range of wavelengths from 490 nm to 560 nm 490-560(30度)AVE is 90% or more; (i-12) average transmittance T in the range of wavelengths from 560 nm to 590 nm 560-590(30度)AVE is 83% or greater; (i-13) wavelength at 50% transmittance IR50 (30度) in the range of 600 nm to 680 nm; (i-14) a maximum transmittance T in the range of wavelengths from 700 nm to 760 nm 700-760(30度)MAX is 2% or less; (i-15) transmittance T at a wavelength of 750 nm 750(30度) is 0.5% or less; (i-16) a maximum transmittance T in the range of wavelengths from 760 nm to 800 nm 760-800(30度)MAX is 1% or less; (i-17) a maximum transmittance T in the range of wavelengths from 800 nm to 900 nm 800-900(30度)MAX is 1% or less; (i-18) a maximum transmittance T in the range of wavelengths from 900 nm to 1100 nm 900-1100(30度)MAX is 5% or less; (i-19) the wavelength IR50 (0度) with the wavelength IR50 (30度) is 8 nm or less. Spectral characteristics (i-20) to (i-23) in the spectral transmittance curve under the condition of an incident angle of 70 degrees: (i-20) a maximum transmittance T in the range of wavelengths from 700 nm to 760 nm 700-760(70度)MAX is 1.5% or less; (i-21) transmittance T at a wavelength of 750 nm 750(70度) is 1.5% or less; (i-22) maximum transmittance T in the range of wavelengths from 760 nm to 800 nm 760-800(70度)MAX is 1.5% or less; (i-23) Maximum transmittance T in the range of wavelengths from 800 nm to 900 nm 800-900(70度)MAX is 1.5% or less.

2. The filter as described in claim 1, wherein, The resin film further comprises a pigment (U) having a maximum absorption wavelength in the resin in the range of 370 nm to 430 nm, and The filter also satisfies the following spectral characteristics (i-24): (i-24) In the spectral transmittance curve at an incident angle of 0 degrees, in the range of wavelengths from 400 nm to 440 nm, the wavelength UV at which the transmittance is 50% is set as UV50 (0度) In the spectral transmittance curve at an incident angle of 30 degrees, in the range of wavelengths from 400 nm to 440 nm, the wavelength UV at which the transmittance is 50% is set as UV50 (30度) At this time, the wavelength UV50 (0度) the wavelength UV50 (30度) is 5 nm or less.

3. The filter as described in claim 1 or 2, wherein, The resin film satisfies all of the following spectral characteristics (ii-1) to (ii-4): (ii-1) the average internal transmittance T in the range of wavelengths from 440 nm to 490 nm in the spectral transmittance curve is at least 84%; and 440-490AVE is at least 84%; and (ii-2) the average internal transmittance T in the range of wavelengths from 490 nm to 560 nm in the spectral transmittance curve is at least 94%. 490-560AVE is at least 94%. (ii-3) In the spectral transmittance curve, the average internal transmittance T in the wavelength range of 560 nm to 590 nm 560-590AVE It is over 80%; (ii-4) In the spectral transmittance curve, the maximum internal transmittance T in the wavelength range of 700 nm to 760 nm. 700-760MAX It is below 5%.

4. The filter as described in claim 1 or 2, wherein, The resin film also satisfies the following spectral characteristics (ii-5): (ii-5) In the spectral transmittance curve, the maximum internal transmittance T in the wavelength range of 760 nm to 800 nm. 760-800MAX It is below 15%.

5. The filter as described in claim 1 or 2, wherein, For the pigment (IR), in the spectral transmittance curve of the coated film obtained by dissolving the pigment (IR) in the resin in such a way that the transmittance at the maximum absorption wavelength is 10%, all of the following spectral characteristics (iii-1) to (iii-3) are satisfied: (iii-1) In the spectral transmittance curve, the average internal transmittance T in the wavelength range of 440 nm to 490 nm 440-490AVE It is over 94%; (iii-2) In the spectral transmittance curve, the average internal transmittance T in the wavelength range of 490 nm to 560 nm 490-560AVE It is over 94%; (iii-3) In the spectral transmittance curve, the average internal transmittance T in the wavelength range of 560 nm to 590 nm 560-590AVE It is over 94%.

6. The filter as described in claim 1 or 2, wherein, The pigment (IR) comprises three or more compounds that have a maximum absorption wavelength in the resin in the range of 680 nm to 800 nm.

7. The filter as claimed in claim 2, wherein, The pigment (U) includes anthocyanin.

8. The filter as described in claim 1 or 2, wherein, The dielectric multilayer film satisfies all of the following spectral characteristics (iv-1) to (iv-12): Spectral characteristics of the spectral transmittance curves under the condition of 0 degrees of incident angle (iv-1) to (iv-6): (iv-1) Average transmittance T in the wavelength range of 440 nm to 490 nm 440-490(0度)AVE It is over 90%; (iv-2) Average transmittance T in the wavelength range of 490 nm to 560 nm 490-560(0度)AVE It is over 90%; (iv-3) Average transmittance T in the wavelength range of 560 nm to 590 nm 560-590(0度)AVE It is over 90%; (iv-4) The shortest wavelength IR50 with 50% transmittance in the range above 600 nm. (0度) Within the range of 630nm to 730nm; (iv-5) Maximum transmittance T in the wavelength range of 700 nm to 760 nm 700-760(0度)MAX It is above 25%; (iv-6) Maximum transmittance T in the wavelength range of 760 nm to 900 nm 760-900(0度)MAX Less than 2%; Spectral characteristics of the spectral transmittance curves under an incident angle of 30 degrees (iv-7) to (iv-12): (iv-7) Average transmittance T in the wavelength range of 440 nm to 490 nm 440-490(30度)AVE It is over 90%; (iv-8) Average transmittance T in the wavelength range of 490 nm to 560 nm 490-560(30度)AVE It is over 90%; (iv-9) Average transmittance T in the wavelength range of 560 nm to 590 nm 560-590(30度)AVE It is over 90%; (iv-10) The shortest wavelength IR50 with 50% transmittance in the wavelength range above 600 nm. (30度) Within the range of 630nm to 730nm; (iv-11) Maximum transmittance T in the wavelength range of 700 nm to 760 nm 700-760(30度)MAX It is above 25%; (iv-12) Maximum transmittance T in the wavelength range of 760 nm to 900 nm 760-900(30度)MAX It is below 2%.

9. The filter as described in claim 1 or 2, wherein, The substrate includes a support and the resin film, the resin film being laminated on at least one main surface of the support, and the support comprising phosphate glass or fluorophosphate glass.

10. The filter as claimed in claim 1 or 2, wherein, The resin is a transparent resin.

11. The filter as claimed in claim 1 or 2, wherein, The resin is a polyimide resin.

Images