Light absorber, article with light absorber, imaging device, and light absorbing composition

Abstract

In the present invention, the transmission spectrum of a light absorber 10 at an angle of incidence of 0° fulfills the following conditions. (I) The average value of the transmittance within the wavelength range of 450-600 nm is 75% or greater. (II) A first wavelength at which the transmittance is 50% within the wavelength range of 350-450 nm is 380 nm to 440 nm. (III) A second wavelength at which the transmittance is 50% within the wavelength range of 650-750 nm 680 nm to 740 nm. (IV) The maximum value of the transmittance within the wavelength range of 350-370 nm is 1% or less. (V) The maximum value of the transmittance within the wavelength range of 800-900 nm is 5% or less. (VI) The maximum value of the transmittance within the wavelength range of 1100-1200 nm is 5% or less.

Description

[Technical Field]

[0001] The present invention relates to a light absorber, an article with a light absorber, an imaging device, and a light absorbing composition. [Background technology]

[0002] In imaging devices using solid-state imaging elements such as CCDs (Charge Coupled Devices) or CMOSs ​​(Complementary Metal Oxide Semiconductors), various optical filters are placed in front of the solid-state imaging elements to obtain images with good color reproducibility. Solid-state imaging elements generally have spectral sensitivity over a wide wavelength range, from the ultraviolet to the infrared regions. Meanwhile, human visual sensitivity exists only in the visible light region. Therefore, a known technique involves placing an optical filter in front of the solid-state imaging element to block part of the infrared or ultraviolet light, in order to bring the spectral sensitivity of the solid-state imaging element in an imaging device closer to the human visual sensitivity.

[0003] Conventionally, such optical filters have typically utilized light reflection by a dielectric multilayer film to block infrared or ultraviolet light. However, in recent years, optical filters equipped with a film containing a light-absorbing agent have been attracting attention. Because the transmittance characteristics of optical filters equipped with a film containing a light-absorbing agent are less affected by the angle of incidence, they can produce good images with little change in color even when light is incident on the optical filter at an angle in an imaging device. Furthermore, light-absorbing optical filters that do not use a light-reflecting film can suppress the occurrence of ghosts and flares caused by multiple reflections by the light-reflecting film, making it easier to obtain good images in backlit conditions or when photographing night scenes. In addition, optical filters equipped with a film containing a light-absorbing agent are advantageous in terms of miniaturizing and thinning imaging devices.

[0004] As such a light absorber, a light absorber formed from phosphonic acid and copper ions is known. For example, Patent Document 1 describes an optical filter having a light absorbing layer containing a light absorber formed from phosphonic acid having a phenyl group or a halogenated phenyl group (phenyl-based phosphonic acid) and copper ions.

[0005] Patent Document 2 also describes an optical filter having a UV-IR absorbing layer capable of absorbing infrared and ultraviolet rays. The UV-IR absorbing layer contains a UV-IR absorber formed from phosphonic acid and copper ions. To ensure that the optical filter has predetermined optical properties, the UV-IR absorbing composition contains, for example, a phenyl-based phosphonic acid and a phosphonic acid having an alkyl group or a halogenated alkyl group (an alkyl-based phosphonic acid).

[0006] Furthermore, Patent Document 3 describes an infrared cut filter that includes an organic dye-containing layer and a copper phosphonate-containing layer.

[0007] On the other hand, Patent Document 4 describes an optical filter that includes an absorption layer, a reflection layer, and a transparent substrate, and that satisfies predetermined requirements in a spectral transmittance curve at an incident angle of 0°. The absorption layer contains a near-infrared absorbing dye such as a squarylium dye. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 6339755 [Patent Document 2] Patent No. 6232161 [Patent Document 3] Patent No. 6281023 [Patent Document 4] International Publication No. 2020 / 004641 Summary of the Invention [Problem to be solved by the invention]

[0009] In the optical filters described in Patent Documents 1 to 3, the cutoff wavelength close to the infrared region is adjusted to the range of 600 to 680 nm. While this is advantageous from the viewpoint of effectively blocking infrared light, it is difficult to say that it is advantageous from the viewpoint of increasing transmittance in the red band. On the other hand, in the optical filter described in Patent Document 4, although the wavelength at which transmittance is 50% near the infrared region is 680 nm or more, a reflective layer is required, and the reflective layer must compensate for the light blocking that is not sufficient with the absorbing layer. For this reason, the optical filter described in Patent Document 4 requires a complicated process to form the reflective layer.

[0010] Therefore, the present invention provides a light absorber that is likely to have high transmittance in the visible light region, particularly in the red light region, and that can effectively block near-infrared light. [Means for solving the problem]

[0011] The present invention provides Provided is a light absorber whose transmission spectrum at an incident angle of 0° satisfies the following conditions (I), (II), (III), (IV), (V), and (VI): (I) The average transmittance in the wavelength range of 450 nm to 600 nm is 75% or more. (II) The first wavelength at which the transmittance is 50% in the wavelength range of 350 nm to 450 nm is 380 nm or more and 440 nm or less. (III) The second wavelength at which the transmittance is 50% in the wavelength range of 650 nm to 750 nm is 680 nm or more and 740 nm or less. (IV) The maximum transmittance in the wavelength range of 350 nm to 370 nm is 1% or less. (V) The maximum transmittance in the wavelength range of 800 nm to 900 nm is 5% or less. (VI) The maximum transmittance in the wavelength range of 1100 nm to 1200 nm is 5% or less.

[0012] The present invention also provides Items and The above-mentioned light absorber formed on a part of the surface of the article, An article with a light absorber is provided.

[0013] The present invention also provides 1. A light absorbing composition comprising: The light-absorbing composition is provided such that the transmission spectrum at an incident angle of 0° of a light-absorbing material obtained by curing the light-absorbing composition satisfies the following conditions (i), (ii), (iii), (iv), (v), and (vi): (i) The average transmittance in the wavelength range of 450 nm to 600 nm is 75% or more. (ii) The first wavelength at which the transmittance is 50% in the wavelength range of 350 nm to 450 nm is 380 nm or more and 440 nm or less. (iii) The second wavelength at which the transmittance is 50% in the wavelength range of 650 nm to 750 nm is 680 nm or more and 740 nm or less. (iv) The maximum transmittance in the wavelength range of 350 nm to 370 nm is 1% or less. (v) The maximum transmittance in the wavelength range of 800 nm to 900 nm is 5% or less. (vi) The maximum transmittance in the wavelength range of 1100 nm to 1200 nm is 5% or less. [Effects of the Invention]

[0014] The light absorber tends to have high transmittance in the visible light region, particularly in the red light region, and can also effectively block near-infrared light. [Brief explanation of the drawings]

[0015] [Figure 1A] FIG. 1A is a cross-sectional view showing an example of a light absorber according to the present invention. [Figure 1B] FIG. 1B is a cross-sectional view showing one example of an article with a light absorber according to the present invention. [Figure 1C] FIG. 1C is a cross-sectional view showing another example of an article with a light absorber according to the present invention. [Figure 1D]FIG. 1D is a cross-sectional view showing an example of an optical member including a light absorber according to the present invention. [Figure 2] FIG. 2 is a diagram showing an example of an imaging device according to the present invention. [Figure 3A] FIG. 3A shows the transmission spectrum of the optical filter according to the first embodiment. [Figure 3B] FIG. 3B shows the transmission spectrum of the optical filter according to the first embodiment. [Figure 3C] FIG. 3C shows the transmission spectrum of the optical filter according to the first embodiment. [Figure 4A] FIG. 4A shows the transmission spectrum of the optical filter according to the second embodiment. [Figure 4B] FIG. 4B shows the transmission spectrum of the optical filter according to the second embodiment. [Figure 4C] FIG. 4C shows the transmission spectrum of the optical filter according to the second embodiment. [Figure 5A] FIG. 5A shows the transmission spectrum of the optical filter according to the third embodiment. [Figure 5B] FIG. 5B shows the transmission spectrum of the optical filter according to the third embodiment. [Figure 5C] FIG. 5C shows the transmission spectrum of the optical filter according to the third embodiment. [Figure 6] FIG. 6 shows the transmission spectrum of the optical filter according to Comparative Example 1. As shown in FIG. [Figure 7] FIG. 7 shows the transmission spectrum of the optical filter according to Comparative Example 2. As shown in FIG. [Figure 8] FIG. 8 shows the transmission spectrum of the optical filter according to Comparative Example 3. [Figure 9] FIG. 9 shows the transmission spectrum of the optical filter according to Comparative Example 4. [Figure 10] FIG. 10 shows the transmission spectrum of the optical filter according to Example 9. DETAILED DESCRIPTION OF THE INVENTION

[0016] It is conceivable that a camera equipped with a CMOS sensor or the like may be installed in a vehicle as part of an in-vehicle system. In addition, such cameras may also be used in driving devices, mobile devices, and transport devices, such as drones and autonomous robots. In this case, the camera mainly captures information such as captured images of the external situation, and the acquired information can support the operation of a driver, operator, or control system for automatic operation. In this case, from the viewpoint of improving the accuracy of recognition of the external environment, it is advantageous for the camera to be equipped with an optical filter that has high transmittance in the visible light range and can effectively block infrared light. The visible light range is the range of electromagnetic waves that humans can recognize as light. The lower limit of this wavelength range is 360 to 400 nm, and the upper limit of this wavelength range is 760 to 830 nm. According to Japanese Industrial Standards (JIS) Z 8120:2001, the visible light range can be 380 to 780 nm. Infrared light, particularly near-infrared light (NIR), is defined as electromagnetic waves with wavelengths beyond the visible light range, up to approximately 1400 nm.

[0017] Traffic lights, road signs, and other such devices may display danger or safety signs in red. Examples of such signs include red traffic lights and regulatory signs (road signs) such as "No Entry," "Stop," and "Slow Down." It is important for an optical filter's transmission spectrum to have high transmittance in the wavelength range corresponding to red in order to accurately recognize surrounding objects, including red traffic lights, regulatory signs, and other such signs. The red color displayed on regulatory signs and other such devices exhibits high reflectance in a wavelength range ranging from 580 to 620 nm, for example, with a lower limit of approximately 780 nm, depending on the specifications of the retroreflective sheeting and other components. Assuming the upper wavelength limit of the visible light range is 780 nm, it is advantageous for the transmission spectrum of the optical filter to have high transmittance in the wavelength range of 580 to 780 nm, or high transmittance in the wavelength range of 620 to 760 nm, or high transmittance in the wavelength range of 620 to 750 nm.

[0018] In addition, the ability of an optical filter to effectively block infrared rays is important for preventing problems such as a camera being unable to capture a good image due to the influence of infrared sensing by vehicles, moving devices, or transport devices traveling nearby. The characteristics of the optical filter described in Patent Document 4 are understood to have been adjusted from this perspective. Meanwhile, the optical filter described in Patent Document 4 includes a reflective layer in addition to an absorbing layer. For this reason, the present inventors undertook extensive trial and error to develop a technology that can increase transmittance in the red band and effectively block near-infrared rays without using a reflective layer. As a result, they have finally completed the present invention.

[0019] In this specification, unless otherwise specified, the visible light region or visible light area is defined as a wavelength range of 380 to 780 nm, and the red band is defined as a wavelength range of 580 to 780 nm or a portion of that range. Furthermore, unless otherwise specified, infrared light is defined as light (electromagnetic waves) with wavelengths greater than 780 nm, the upper limit of the visible light region, and ranging up to 1400 nm, and corresponds to near-infrared light (NIR). Ultraviolet light is defined as light (electromagnetic waves) with wavelengths ranging from 280 nm to 380 nm, the lower limit of the visible light region, and corresponds to UV-A and some of UV-B.

[0020] Hereinafter, embodiments of the present invention will be described. Note that the following description is for illustrative purposes only and the present invention is not limited to the following embodiments.

[0021] (light absorber) 1A is a cross-sectional view showing a light absorber 10. The transmission spectrum of the light absorber 10 at an incident angle of 0° satisfies the following conditions (I), (II), (III), (IV), (V), and (VI). (I) Average transmittance T in the wavelength range of 450 nm to 600 nm A 0(450-600) is 75% or more. (II) a first wavelength λ at which the transmittance is 50% in the wavelength range of 350 nm to 450 nm 50 0(UV)is between 380 nm and 440 nm. (III) a second wavelength λ at which the transmittance is 50% in the wavelength range of 650 nm to 750 nm 50 0(IR) is between 680 nm and 740 nm. (IV) Maximum transmittance T in the wavelength range of 350 nm to 370 nm M 0(350-370) is less than 1%. (V) Maximum transmittance T in the wavelength range of 800 nm to 900 nm M 0(800-900) is less than 5%. (VI) Maximum transmittance T in the wavelength range of 1100 nm to 1200 nm M 0(1100-1200) is less than 5%.

[0022] When the conditions (I), (II), and (III) are satisfied, the transmittance in the visible light region is likely to be high, and in particular, when the condition (III) is satisfied, the transmittance of the light absorber 10 in the red band is likely to be high. In addition, when the conditions (V) and (VI) are satisfied, the light absorber 10 can effectively block infrared rays. Furthermore, when the condition (IV) is satisfied, the light absorber 10 can effectively block ultraviolet rays.

[0023] Regarding condition (I), the average value T A 0(450-600) is preferably 80% or more, and more preferably 85% or more. In addition, the transmission spectrum of the light absorber 10 at an incident angle of 0° preferably further satisfies the following condition (Ia): (Ia) Average transmittance T in the wavelength range of 650 nm to 670 nm A 0(650-670) is more than 70%.

[0024] Regarding the condition (Ia), the average value T A 0(650-670) is preferably 72% or more, and more preferably 74% or more.

[0025] Regarding the condition (II), the first wavelength λ 50 0(UV) is preferably 385 nm or more and 420 nm or less, and more preferably 390 nm or more and 410 nm or less.

[0026] Regarding the condition (III), the second wavelength λ 50 0(IR) is preferably greater than 680 nm and equal to or less than 740 nm, more preferably equal to or greater than 685 nm and equal to or less than 730 nm, and even more preferably equal to or greater than 690 nm and equal to or less than 720 nm.

[0027] Regarding condition (IV), the maximum value T M 0(350-370) is preferably 0.5% or less.

[0028] Regarding the condition (V), the maximum value T M 0(800-900) is preferably 3% or less.

[0029] Regarding the condition (VI), the maximum value T M 0(1100-1200) is preferably 3% or less.

[0030] The transmission spectrum of the light absorber 10 at an incident angle of 0° further satisfies, for example, the following condition (VII): This makes it easier to reliably increase the transmittance of the light absorber 10 in the red band. (VII) Transmittance T at a wavelength of 750 nm 0(750) is more than 7%.

[0031] Regarding the condition (VII), the transmittance T 0(750) is preferably 10% or more, and more preferably 15% or more.

[0032] The transmission spectrum of the light absorber 10 at an incident angle of 0° further satisfies, for example, the following condition (VIII): This makes it easier to reliably increase the transmittance of the light absorber 10 in the red band. (VIII) Transmittance T at a wavelength of 780 nm 0(780) is more than 3%.

[0033] Regarding the condition (VIII), the transmittance T 0(780) is preferably 4% or more, and more preferably 5% or more.

[0034] The transmission spectrum of the light absorber 10 at an incident angle of 55° is, for example, a third wavelength λ at which the transmittance is 50% in the wavelength range of 350 nm to 450 nm. 50 55(UV) The third wavelength λ 50 55(UV) and the first wavelength λ 50 0(UV) The absolute value of the difference Δλ 50 0 / 55(UV) is, for example, 12 nm or less. This tends to reduce the incidence angle dependency of the transmission spectrum of the light absorber 10. Therefore, for example, it is possible to suppress changes in color in the central and peripheral parts of an image obtained by an imaging device equipped with the light absorber 10. In addition, it is possible to suppress changes in color in an image of a subject present within the range of the angle of view that can be captured by an imaging device equipped with the light absorber 10. The absolute value Δλ 50 0 / 55(UV) is preferably 10 nm or less, more preferably 8 nm or less, and even more preferably 6 nm or less.

[0035] The transmission spectrum of the light absorber 10 at an incident angle of 55° is, for example, a fourth wavelength λ 1 at which the transmittance is 50% in the wavelength range of 650 nm to 750 nm. 50 55(IR) The fourth wavelength λ 50 55(IR) and the second wavelength λ 50 0(IR) The absolute value of the difference Δλ 50 0 / 55(IR) is, for example, 24 nm or less. This tends to reduce the incidence angle dependency of the transmission spectrum of the light absorber 10. Therefore, for example, it is possible to suppress changes in color in the central and peripheral parts of an image obtained by an imaging device equipped with the light absorber 10. In addition, it is possible to suppress changes in color in an image of a subject present in the range of the angle of view that can be captured by an imaging device equipped with the light absorber 10. The absolute value Δλ 500 / 55(IR) is preferably 20 nm or less, more preferably 18 nm or less, and even more preferably 16 nm or less.

[0036] The transmission spectrum of the light absorber 10 at an incident angle of 45° is, for example, a wavelength λ at which the transmittance becomes 50% in the wavelength range of 350 nm to 450 nm. 50 45(UV) The wavelength λ 50 45(UV) and the first wavelength λ 50 0(UV) The absolute value of the difference Δλ 50 0 / 45(UV) is, for example, 10 nm or less, preferably 8 nm or less, and more preferably 5 nm or less.

[0037] The transmission spectrum of the light absorber 10 at an incident angle of 35° is, for example, a wavelength λ at which the transmittance becomes 50% in the wavelength range of 350 nm to 450 nm. 50 35(UV) The wavelength λ 50 35(UV) and the first wavelength λ 50 0(UV) The absolute value of the difference Δλ 50 0 / 35(UV) is, for example, 8 nm or less, preferably 6 nm or less, and more preferably 4 nm or less.

[0038] The transmission spectrum of the light absorber 10 at an incident angle of 45° is, for example, a wavelength λ at which the transmittance becomes 50% in the wavelength range of 650 nm to 750 nm. 50 45(IR) The wavelength λ 50 45(IR) and the second wavelength λ 50 0(IR) The absolute value of the difference Δλ 50 0 / 45(IR) is, for example, 18 nm or less, preferably 16 nm or less, and more preferably 12 nm or less.

[0039] The transmission spectrum of the light absorber 10 at an incident angle of 35° is, for example, a wavelength λ at which the transmittance becomes 50% in the wavelength range of 650 nm to 750 nm.50 35(IR) The wavelength λ 50 35(IR) and the second wavelength λ 50 0(IR) The absolute value of the difference Δλ 50 0 / 35(IR) is, for example, 12 nm or less, preferably 10 nm or less, and more preferably 8 nm or less.

[0040] The light absorber 10 typically contains a predetermined light absorbing agent. The light absorber contained in the light absorber 10 is not limited to a specific substance as long as the transmission spectrum of the light absorber 10 at an incident angle of 0° satisfies the conditions (I) to (VI). The light absorber 10 may contain, for example, a light absorbing compound containing a phosphonic acid and a copper component as a light absorber, and may also contain an ultraviolet absorber that absorbs at least a portion of ultraviolet light. The light absorber 10 is in a solid state such as a film or a membrane formed on a predetermined object, and can be produced by curing a liquid light absorbing composition that is its precursor. When the light absorber 10 contains a compound that can exhibit a predetermined function, the light absorbing composition that is its precursor may naturally also contain the compound or its precursor.

[0041] (phosphonic acid) The phosphonic acid in the light absorbing compound contained in the light absorber 10 or the light absorbing composition is not limited to a specific phosphonic acid as long as the transmission spectrum of the light absorber 10 at an incident angle of 0° satisfies the conditions (I) to (VI). The phosphonic acid is represented, for example, by the following formula (a). In formula (a), R1 is an alkyl group or a halogenated alkyl group in which at least one hydrogen atom in the alkyl group is substituted with a halogen atom. In this case, the transmission band of the light absorber 10 is likely to extend to a wavelength of around 700 nm, and the light absorber 10 is likely to have desired transmittance characteristics.

[0042] [ka]

[0043] The phosphonic acid is, for example, methylphosphonic acid, ethylphosphonic acid, normal (n-)propylphosphonic acid, isopropylphosphonic acid, normal (n-)butylphosphonic acid, isobutylphosphonic acid, sec-butylphosphonic acid, tert-butylphosphonic acid, or bromomethylphosphonic acid.

[0044] (Copper component) The copper component in the light-absorbing compound contained in the light absorber 10 or the light-absorbing composition conceptually encompasses copper ions, copper complexes, and copper-containing compounds. The copper component can have favorable absorption characteristics for a portion of light in the near-infrared region and high transmittance for light in the visible light region with wavelengths of 450 nm to 680 nm. Specifically, excellent near-infrared absorption characteristics are exhibited by selectively absorbing light of wavelengths in the near-infrared region corresponding to this energy through the transition of electrons in the d orbital of the divalent copper ion. In particular, the divalent copper ion may be mixed with phosphonic acid in the form of a copper salt, and the phosphonic acid may be coordinated to the copper ion to form a copper complex (copper salt).

[0045] The source of the copper component to be coordinated with the phosphonic acid may be, but is not limited to, an anhydrous or hydrated copper salt of an organic acid such as copper acetate, copper benzoate, copper pyrophosphate, or copper stearate, or a mixture thereof. These copper salts may be used alone, or multiple copper salts or mixtures thereof may be used.

[0046] The contents of the copper component and phosphonic acid in the light absorber 10 are not limited to specific values. The ratio of the content of the phosphonic acid to the content of the copper component in the light absorber 10 is, for example, 0.3 to 1.5 on a substance amount (molar) basis. The ratio of the content of the phosphonic acid to the content of the copper component in the light absorber 10 may be preferably 0.4 to 1.4, more preferably 0.6 to 1.2, and even more preferably 0.8 to 1.1.

[0047] (phosphate ester) The light absorber 10 or the light-absorbing composition may further contain, for example, a phosphate ester compound. The phosphate ester facilitates proper dispersion of the light-absorbing compound in the light absorber 10. The phosphate ester may function as a dispersant for the light-absorbing compound, or a portion of the phosphate ester may react with a metal component to form a compound. For example, the phosphate ester may coordinate with or react with the light-absorbing compound, or may partially form a complex with a copper component. As long as the light absorber 10 satisfies the conditions regarding a predetermined transmission spectrum, a compound containing a phosphate ester and a copper component may also absorb light of some wavelengths. The phosphate ester may not be substantially present in the light-absorbing composition, which is the precursor of the light absorber 10, as long as the light-absorbing substance containing at least a phosphonic acid and a copper component is properly dispersed. Furthermore, when an alkoxysilane monomer, described below, is contained in the light-absorbing composition to impart dispersion function, the amount of phosphate ester added can be reduced.

[0048] The phosphate ester is not limited to a specific phosphate ester or compound thereof. The phosphate ester may have, for example, a polyoxyalkyl group. Examples of such phosphate esters include Plysurf A208N: polyoxyethylene alkyl (C12, C13) ether phosphate ester, Plysurf A208F: polyoxyethylene alkyl (C8) ether phosphate ester, Plysurf A208B: polyoxyethylene lauryl ether phosphate ester, Plysurf A219B: polyoxyethylene lauryl ether phosphate ester, Plysurf AL: polyoxyethylene styrenated phenyl ether phosphate ester, Plysurf A212C: polyoxyethylene tridecyl ether phosphate ester, and Plysurf A215C: polyoxyethylene tridecyl ether phosphate ester. These are all products manufactured by Daiichi Kogyo Seiyaku Co., Ltd. Additionally, examples of phosphate esters include NIKKOL DDP-2: polyoxyethylene alkyl ether phosphate ester, NIKKOL DDP-4: polyoxyethylene alkyl ether phosphate ester, and NIKKOL DDP-6: polyoxyethylene alkyl ether phosphate ester. These are all products manufactured by Nikko Chemicals Co., Ltd. These phosphate ester compounds may be used alone or in combination.

[0049] The contents of phosphonic acid and phosphate ester in the light absorber 10 are not limited to specific values. The ratio of the content of phosphonic acid to the content of phosphate ester in the light absorber 10 is, for example, 0.6 to 1.6 on a mass basis. This suppresses hydrolysis of the phosphate ester even when the light absorber 10 comes into contact with water vapor, and the light absorber 10 is likely to have good weather resistance. The ratio of the content of phosphonic acid to the content of phosphate ester in the light absorber 10 may be preferably 0.7 to 1.5, and more preferably 0.8 to 1.4.

[0050] Furthermore, the ratio of the copper component content to the phosphorus component content in the light absorber 10 is not limited to a specific value. The ratio of the copper component content to the phosphorus component content in the light absorber 10 may be, for example, 1.0 to 3.0, and preferably 1.5 to 2.0, on a mass basis. The phosphorus component may be derived from phosphonic acid contained in the light absorber 10 or a light-absorbing composition that is a precursor thereof, or may be derived from phosphonic acid and phosphate ester contained in the light absorber 10 or a light-absorbing composition that is a precursor thereof, or may be contained in other additives.

[0051] (Alkoxysilane or its hydrolyzate) The light absorber 10 or the light-absorbing composition may further contain, for example, an alkoxysilane. Examples of alkoxysilane include alkoxysilane monomers and their partial hydrolysis products. The presence of alkoxysilane can prevent light-absorbing agent particles from agglomerating together, so that even if the content of the aforementioned phosphate ester is reduced, the light absorber is well dispersed in the light-absorbing composition or a light absorber cured therefrom. Furthermore, when a light-absorbing agent or a light-absorbing filter is manufactured using the light-absorbing composition, it is desirable to perform a process that sufficiently induces the hydrolysis reaction and condensation polymerization reaction of the alkoxysilane, thereby forming a siloxane bond (-Si-O-Si-), and thereby providing the light absorber with good moisture resistance. In addition, the light absorber has good heat resistance. This is because siloxane bonds have higher bond energy and are more chemically stable than bonds such as -C-C- and -C-O- bonds, and therefore have excellent heat and moisture resistance.

[0052] Furthermore, when the light-absorbing composition contains an alkoxysilane, the light-absorbing composition may be exposed to a relatively humid atmosphere for a certain period of time when curing the composition to produce a light absorber, which is called a humidification treatment. It is believed that the water component in the atmosphere promotes hydrolysis of the alkoxysilane contained in the light-absorbing composition or the light absorber, thereby promoting the formation of siloxane bonds. Furthermore, the humidification treatment allows the formation of a hard, dense light absorber 10 without the fine particles containing the light absorber agglomerating.

[0053] The alkoxysilane is not limited to a specific alkoxysilane as long as it can undergo a hydrolysis and condensation polymerization reaction to form a hydrolysis-condensation polymerization compound having a siloxane bond in the light absorber 10. The alkoxysilane may be, for example, a monomer such as tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, or 3-glycidoxypropylmethyldiethoxysilane, or may be a dimer or oligomer in which parts of these alkoxysilanes are bonded together.

[0054] (curable resin) The light absorber 10 or the light-absorbing composition further contains, for example, a curable resin. The resin is required to be capable of dispersing or dissolving the light-absorbing compound containing the above-mentioned phosphonic acid and copper component and retaining it. Furthermore, the resin is preferably liquid in an uncured or unreacted state and capable of dispersing or dissolving the light-absorbing compound containing the above-mentioned phosphonic acid and copper component. Furthermore, the resin is preferably one that contains the light-absorbing compound and can be applied as an uncured liquid resin to any object by a coating method such as spin coating, spraying, dipping, or dispensing to form a coating film. The object on which the coating film is formed is a substrate having any surface, whether flat or curved. The uncured liquid resin is preferably one that can be cured by heating, humidification, irradiation with energy such as light, or a combination of these methods. The resin is not limited to a specific resin as long as the transmission spectrum of the light absorber 10 at an incident angle of 0° satisfies any one of the conditions (I) to (VI), or the transmission spectrum of a plate-like body having a smooth surface and a thickness of 1 mm, formed by curing the resin, is 90% or more in the wavelength range of 450 nm to 800 nm. Examples of the resin include cyclic polyolefin resins, epoxy resins, polyimide resins, modified acrylic resins, silicone resins, and polyvinyl resins such as PVB.

[0055] (curing catalyst) The light absorber 10 or the light absorbing composition that is its precursor may contain a curing catalyst that is involved in the curing of the resin described above. catalyst may be a catalyst that can control conditions such as the resin curing speed, the resin curing reactivity, and the hardness of the cured resin.

[0056] The curing catalyst is preferably an organic compound containing a metal component (organometallic compound). The organometallic compound is not limited to a specific compound. The organometallic compound may be an organoaluminum compound, an organotitanium compound, an organozirconium compound, an organozinc compound, or an organotin compound.

[0057] Examples of organic aluminum compounds include, but are not limited to, aluminum salt compounds such as aluminum triacetate and aluminum octylate, aluminum alkoxide compounds such as aluminum trimethoxide, aluminum triethoxide, aluminum dimethoxide, aluminum diethoxide, aluminum triallyl oxide, aluminum diallyl oxide, and aluminum isopropoxide, as well as aluminum methoxybis(ethylacetoacetate), aluminum methoxybis(acetylacetonate), aluminum ethoxybis(ethylacetoacetate), aluminum ethoxybis(acetylacetonate), and aluminum isopropoxybis(ethylacetoacetate). Examples of the aluminum chelate compounds include aluminum isopropoxybis(methylacetoacetate), aluminum isopropoxybis(t-butylacetoacetate), aluminum butoxybis(ethylacetoacetate), aluminum dimethoxy(ethylacetoacetate), aluminum dimethoxy(acetylacetonate), aluminum diethoxy(ethylacetoacetate), aluminum diethoxy(acetylacetonate), aluminum diisopropoxy(ethylacetoacetate), aluminum diisopropoxy(methylacetoacetate), aluminum tris(ethylacetoacetate), and aluminum tris(acetylacetonate). These may be used alone or in combination.

[0058] Examples of organic titanium compounds include, but are not limited to, titanium chelates such as titanium tetraacetylacetonate, dibutyloxytitanium diacetylacetonate, titanium ethylacetoacetate, titanium octylene glycolate, and titanium lactate, as well as titanium alkoxides such as tetraisopropyl titanate, tetrabutyl titanate, tetramethyl titanate, tetra(2-ethylhexyl titanate), titanium tetra-2-ethylhexoxide, titanium butoxy dimer, titanium tetra-normal butoxide, titanium tetraisopropoxide, and titanium diisopropoxybis(ethylacetoacetate). These may be used alone or in combination.

[0059] Examples of organic zirconium compounds include, but are not limited to, zirconium chelates such as zirconium tetraacetylacetonate, zirconium dibutoxybis(ethylacetoacetate), zirconium monobutoxyacetylacetonate bis(ethylacetoacetate), zirconium tributoxymonoacetylacetonate, and zirconium tetraacetylacetonate, as well as zirconium alkoxides such as zirconium tetra-normal butoxide and zirconium tetra-normal propoxide. These may be used alone or in combination.

[0060] Examples of organic zinc compounds include zinc alkoxides such as dimethoxyzinc, diethoxyzinc, and ethylmethoxyzinc, which may be used alone or in combination.

[0061] Examples of organotin compounds include tin alkoxides such as dimethyltin oxide, diethyltin oxide, dipropyltin oxide, dibutyltin oxide, dipentyltin oxide, dihexyltin oxide, diheptyltin oxide, and dioctyltin oxide, which may be used alone or in combination.

[0062] As a curing catalyst, at least one of an alkoxide having a metal component and a hydrolyzate of an alkoxide having a metal component may be further contained. The alkoxide having a metal component and the hydrolyzate of an alkoxide having a metal component are collectively referred to as "metal alkoxide compounds." The metal alkoxide is represented by the general formula M(OR) n (M is a metal element, n is an integer of 1 or greater), and is a compound in which the hydrogen atom of a hydroxyl group of an alcohol is substituted with the metal element M. Metal alkoxides form M-OH upon hydrolysis and further form M-O-M bonds upon reaction with metal alkoxides of other molecules. For example, when a light-absorbing composition contains a compound such as a curable resin and the flowable light-absorbing composition is cured to form the light absorber 10, the metal alkoxide compound may function as a catalyst to promote curing of the light-absorbing composition. When the light-absorbing composition is cured by heat treatment, the higher the heat treatment temperature, the more likely it is that environmental resistance, such as heat resistance, will be improved. On the other hand, high heat treatment temperatures may deteriorate the properties of some light-absorbing compounds or ultraviolet absorbers described below. Deterioration of the properties of the ultraviolet absorber may cause the wavelength of light absorbed by the ultraviolet absorber to deviate from the intended absorption wavelength. The absorption ability of the ultraviolet absorber may also be reduced or eliminated. However, when the light absorber 10 contains a metal alkoxide compound, curing of the light-absorbing composition can be promoted even without high heat treatment temperatures. As a result, the light absorber 10 is likely to have high environmental resistance.

[0063] The metal component contained in the metal alkoxide compound is not limited to a specific component. Examples of the metal component include Al, Ti, Zr, Zn, Sn, and Fe. Examples of metal alkoxides that can be used include aluminum alkoxides CAT-AC and DX-9740 manufactured by Shin-Etsu Chemical Co., Ltd., aluminum alkoxide Orgatix AL-3001 manufactured by Matsumoto Fine Chemical Co., Ltd., aluminum isopropoxide manufactured by Tokyo Chemical Industry Co., Ltd., titanium alkoxides D-20, D-25, and DX-175 manufactured by Shin-Etsu Chemical Co., Ltd., titanium alkoxides Orgatix TA-8, TA-21, TA-30, TA-80, and TA-90 manufactured by Matsumoto Fine Chemical Co., Ltd., zirconia alkoxides D-15 and D-31 manufactured by Shin-Etsu Chemical Co., Ltd., and zirconia alkoxides Orgatix ZA-45 and ZA-65 manufactured by Matsumoto Fine Chemical Co., Ltd.

[0064] The ratio of the content of the copper component to the content of the metal component contained in the metal alkoxide compound in the light absorber 10 is not limited to a specific value. The ratio of the content of the copper component to the content of the metal component contained in the metal alkoxide compound in the light absorber 10 is 1×10 2 ~7×10 2 may be, preferably 2 × 10 2 ~6×10 2 and more preferably 3×10 2 ~5×10 2 may be.

[0065] Furthermore, the ratio of the content of the phosphorus component to the content of the metal component contained in the metal alkoxide compound in the light absorber 10 is not limited to a specific value. The ratio of the content of the phosphorus component to the content of the metal component contained in the metal alkoxide compound in the light absorber 10 is 0.5×10 on a mass basis. 2 ~5×10 2 may be, and preferably 1 × 10 2 ~4×10 2 and more preferably 1.5 × 10 2 ~3×102 may be.

[0066] (ultraviolet absorber) The light absorber 10 or its precursor, a light-absorbing composition, may contain an ultraviolet absorber that absorbs a portion of ultraviolet light. The ultraviolet absorber is not limited to a specific compound as long as the transmission spectrum of the light absorber 10 at an incident angle of 0° satisfies the conditions (I) to (VI). The ultraviolet absorber is, for example, a compound that does not have both a hydroxy group and a carbonyl group in its molecule, i.e., a compound that does not have both a hydroxy group and a carbonyl group in its molecule when represented by a structural formula. The curing of the light-absorbing composition can be promoted by, for example, the coordination of a reactant or precursor to a specific position in the molecule of an alkoxide containing a metal component. For example, the presence of a group that is easily coordinated with a substance other than the substance used in the reaction for curing the light-absorbing composition may weaken the catalytic activity. In particular, both hydroxy groups and carbonyl groups have high electron-donating properties, and when an alkoxide compound reacts or coordinates with a UV absorber containing these groups, some of them form a complex, which may change the UV absorption properties inherent to the UV absorber. However, when the ultraviolet absorber is a compound that does not have both a hydroxy group and a carbonyl group in the molecule, the alkoxide compound is unlikely to form a complex with the ultraviolet absorber, and the ultraviolet absorber's inherent ultraviolet absorbing properties are likely to be exhibited. Note that the ultraviolet absorber may contain only one of a hydroxy group and a carbonyl group in the molecule.

[0067] The UV absorber is preferably selected from the viewpoints of absorbing light in a desired wavelength range, being compatible with a specific solvent, dispersing well in a light-absorbing composition, particularly a curable resin, and having excellent environmental resistance. Examples of UV absorbers include benzophenone-based compounds, benzotriazole-based compounds, salicylic acid-based compounds, and triazine-based compounds. For example, Tinuvin PS, Tinuvin 99-2, Tinuvin 234, Tinuvin 326, Tinuvin 329, Tinuvin 900, Tinuvin 928, Tinuvin 405, and Tinuvin 460 can be used as UV absorbers. These are UV absorbers manufactured by BASF, and Tinuvin is a registered trademark.

[0068] The content of the ultraviolet absorber in the light absorber 10 is not limited to a specific value as long as the transmission spectrum of the light absorber 10 at an incident angle of 0° satisfies the conditions (I) to (VI). A high absorption capacity can be achieved by including a small amount of ultraviolet absorber. The ratio of the content of the ultraviolet absorber to the content of the copper component in the light absorber 10 is, for example, 0.01 to 1, preferably 0.02 to 0.5, and more preferably 0.07 to 0.14, by mass. The ratio of the content of the ultraviolet absorber to the content of the phosphorus component in the light absorber 10 is, for example, 0.02 to 2, preferably 0.04 to 1, and more preferably 0.12 to 0.26, by mass.

[0069] Figure 1 A As shown in Fig. 1, the light absorber 10 is, for example, in the form of a film. In this specification, the term "film" is synonymous with a coating or a layer. The light absorber 10 is not limited to being in the form of a film.

[0070] As long as the transmission spectrum of the light absorber 10 at an incident angle of 0° satisfies the conditions (I) to (VI), the thickness of the light absorber 10 is not limited to a specific value. The thickness of the light absorber 10 is, for example, 120 μm or less, preferably 100 μm or less, and more preferably 80 μm or less. A small thickness of the light absorber 10 is advantageous from the viewpoint of reducing the height of an imaging device including the light absorber 10.

[0071] Silicone resin is preferably used as the curable resin because it provides flexibility to the film-like light absorber 10 and allows for the incorporation of a light-absorbing compound containing phosphonic acid and a copper component, which has excellent light absorption properties, as a light absorber. A curing catalyst may also be added to improve the curing properties of resins such as silicone resins. Silicone resin curing catalysts are preferably compounds containing metal components, such as chelates containing metal components and alkoxides containing metal components. Meanwhile, conventionally, when UV absorbers are added to control the spectrum on the short wavelength side, interactions between the metal components contained in the curing catalyst and the UV absorber may occur, resulting in a significant shift in the cut wavelength on the short wavelength side, and thus altering the absorption characteristics inherent to the UV absorber. Therefore, previously, a layer containing a UV absorber and a layer of a resin containing a light absorber containing phosphonic acid and copper had to be provided as separate layers, which tended to increase the thickness of the light absorber. In the present invention, even when a single layer or film contains a curing catalyst for a resin made of a compound containing a metal component, the UV absorber can be incorporated into the same layer or film by using a specific UV absorber. This allows the ultraviolet absorber to exhibit its inherent ultraviolet absorbing performance, making it possible to obtain the light absorber 10 with fewer layers, and ultimately reducing the thickness of the light absorber 10.

[0072] The light absorber 10 can be produced, for example, by curing a predetermined light absorbing composition.

[0073] The light-absorbing composition is not limited to a specific composition as long as the transmission spectrum of the light absorber 10 at an incident angle of 0° satisfies the conditions (I) to (VI). The light-absorbing composition may contain, for example, a light-absorbing compound containing a phosphonic acid and a copper component, and an ultraviolet absorber that absorbs at least a portion of ultraviolet light. With regard to the light-absorbing compound, reference can be made to the description of the light-absorbing compound in the light absorber 10.

[0074] The light-absorbing composition further contains, for example, at least one of an alkoxide having a metal component and a hydrolysate of an alkoxide having a metal component. For the alkoxide having a metal component and the hydrolysate of an alkoxide having a metal component, the description of the alkoxide compound in the light absorber 10 can be referred to.

[0075] As long as the transmission spectrum of the light absorber 10 at an incident angle of 0° satisfies the conditions (I) to (VI), the ultraviolet absorber in the light-absorbing composition is not limited to a specific compound. For examples of ultraviolet absorbers, the description of the ultraviolet absorber in the light absorber 10 can be referred to. The ultraviolet absorber is, for example, a compound that does not contain both a hydroxy group and a carbonyl group in the molecule. In other words, the ultraviolet absorber may be a compound that contains only either a hydroxy group or a carbonyl group.

[0076] The light-absorbing composition further contains, for example, a phosphate ester, which facilitates proper dispersion of the light-absorbing compound in the light-absorbing composition. With regard to the phosphate ester, reference can be made to the description of the phosphate ester in the light absorber 10.

[0077] The light-absorbing composition further contains, for example, a curable resin. With regard to the curable resin, reference can be made to the description of the resin in the light absorber 10.

[0078] In preparing the light-absorbing composition, the source of the copper component in the light-absorbing compound is not limited to a specific substance. The source of the copper component is, for example, a copper salt. The copper salt may be an anhydride or hydrate of copper chloride, copper formate, copper stearate, copper benzoate, copper pyrophosphate, copper naphthenate, or copper citrate. For example, copper acetate monohydrate is expressed as Cu(CH3COO)2·H2O, and one mole of copper acetate monohydrate provides one mole of copper ions.

[0079] For example, a member in which the light absorber 10 is formed on the surface of an article can be used as an optical filter. In addition, the light absorber 10 can be formed on the surface of an article and then peeled off, so that the light absorber 10 itself can be used independently as an optical filter. The method for producing the light absorber 10 is not limited to a specific method. The light absorber 10 may be produced by methods such as casting (casting), compression molding, vacuum forming, press molding, injection molding, blow molding, and extrusion molding.

[0080] As shown in Fig. 1A, the light absorber 10 may be used alone. On the other hand, as shown in Fig. 1B, an article with a light absorber 1a can be provided. The article with a light absorber 1a includes an article 20 and the light absorber 10. The light absorber 10 covers at least a part of the surface of the article 20.

[0081] The shape of the article 20 in the light absorber-equipped article 1a is not limited to a specific shape. The article 20 may be a flat member or substrate. The article 20 is not limited to a specific article. The article 20 may be, for example, an optical element (including an acousto-optical element) such as a lens, a mirror, a prism, a diffuser, a flat microlens array, a polarizer, a diffraction grating, a hologram, an optical modulation element, an optical deflection element, or a filter. The article 20 may be a solid-state imaging device, a window or windshield of a building or an automobile, a light-transmitting shield such as a helmet or goggles, or a display device such as a display and a screen. The light absorber-equipped article 1a may be a so-called optical filter. The surface of the article 20 covered with the light absorber 10 may be flat, curved, or uneven.

[0082] The light absorber 10 may be obtained by molding an optical element such as a lens using the light absorbing composition. In this case, the light absorber 10 may be used alone.

[0083] (functional membrane) 1C and 1D, the article with a light absorber 1a or the light absorber 10 may include another functional film 30. The other functional film is not limited to a specific film, and may be a hard coating film (hard coat) for improving scratch resistance, a reflection-reducing film or an anti-reflection film for reducing reflected light belonging to a specific wavelength range from the surface of the article with a light absorber 1a or the light absorber 10 when light is incident on the article or the light absorber 10 (hereinafter, these are collectively referred to as "anti-reflection films"), a film for increasing the reflection of light belonging to a specific wavelength range from the surface of the article with a light absorber 1a or the light absorber 10 when light is incident on the article or the light absorber 10 (hereinafter, referred to as "reflective film"), a polarizing film for reducing the transmittance of light having a polarization direction other than a specific direction when light is incident on the article with a light absorber 1a or the light absorber 10, or a selective wavelength light-absorbing film that absorbs light in a certain wavelength range by other configuration, a predetermined action, or the like. The functional film 30 may be configured as a single film of any of these functional films, or may be configured as a plurality of functional films.

[0084] When the light absorber-equipped article 1a or the light absorber 10 has an antireflection film as the functional film 30, the light absorber-equipped article 1a or the light absorber 10 may have the antireflection film on one or both of its main surfaces. Here, the main surface is the surface having the largest area of ​​the substrate of the light absorber-equipped article 1a or the light absorber 10, etc.

[0085] The anti-reflection film has, for example, one or more layers made of one or more materials. The material constituting the anti-reflection film is not limited to a specific material. The anti-reflection film may be made of, for example, SiO2 or SiO 1.5 , TiO2 and TiO 1.5The antireflection coating may be a film formed by a sol-gel method or the like, mainly composed of TiO2, Ta2O3, SiO2, Nb2O5, ZnS, MgF, or a mixture thereof, and formed by a method such as vapor deposition, sputtering, or ion plating. The vapor deposition method may be ion beam assisted vapor deposition. The antireflection coating may be a single-layer film containing the above-mentioned material, or a multilayer film (dielectric multilayer film) in which films of different materials are alternately stacked. The antireflection coating may be formed in contact with the light absorber 10, or in contact with another functional layer film formed in contact with the light absorber 10.

[0086] Furthermore, when the light absorber-equipped article 1a or the light absorber 10 has a light-reflecting film as the functional film 30, the light absorber 10 and the light-reflecting film may cooperate to exhibit a light-blocking function, and this cooperation can reduce or block the transmission of light belonging to a specific wavelength range, thereby reducing the burden required of the light absorber 10 in terms of light absorption properties. This allows, for example, a reduction in the thickness of the light absorber 10. Furthermore, the content of a light-absorbing compound such as a light absorber or the content of an ultraviolet absorber in the light absorber 10 can also be reduced.

[0087] The selective wavelength light absorbing film is not limited to a specific film, and may be a film of a metal such as Ag (silver), Al (aluminum), Au (gold), or Pt (platinum), or may be a film containing a compound containing one or more of these metals or other metals. In particular, a metal film can accommodate a wide wavelength range and has a simple structure, so it can be used as a simple film that exhibits light reflection or light absorption functions. Such a selective wavelength light absorbing film can be used as a neutral density (ND) or half mirror.

[0088] When a UV absorber containing hydroxyl and carbonyl groups is used in a light absorber, the UV absorber may react with metal ions contained in functional films such as reflective and anti-reflective films, resulting in structural changes due to complex formation. In such cases, the absorption band shifts to longer wavelengths, resulting in changes in UV absorption ability and the loss of the desired optical properties. The UV absorber contained in light absorber 10 is a compound that does not contain both hydroxyl and carbonyl groups within its molecule. Therefore, even if a functional film containing metal components other than Si, such as Ti, Mg, or Ta, is formed, the optical properties, particularly the expected decrease in transmittance in the visible range, due to the reaction between the metal component and the UV absorber at the interface between the functional film and the light absorber are not affected. Another advantage is that it can suppress problems such as film peeling or wrinkling at the interface due to complex formation reactions.

[0089] A device including the light absorber 10 can be provided. The use of such a device is not limited to a specific application. Such a device is, for example, an in-vehicle camera or an in-vehicle sensor. In this case, since the light absorber 10 has a predetermined ultraviolet absorption property, it can protect an imaging element and a sensor element from ultraviolet rays. Furthermore, since the light absorber 10 has high transmittance at a wavelength of around 700 nm, the light absorber 10 can be used in sensing systems such as light detection and ranging (Lidar) systems using infrared or red lasers. Since the light absorber 10 has high transmittance, particularly for red light, a device including the light absorber 10 is likely to have an improved ability to recognize objects such as red traffic lights and road signs. In addition, since the light absorber 10 blocks light in a specific wavelength range by absorbing it, ghosts and flares can be suppressed in a device including the light absorber 10. Furthermore, Lidar systems can be installed not only in in-vehicle devices but also in portable information terminals such as smartphones.

[0090] As shown in FIG. 2, for example, an imaging device 100 including a light absorber 10 can be provided. The imaging device 100 further includes, for example, a lens system 40 and an imaging element 50. The light absorber 10 is disposed, for example, between the lens system 40 and the imaging element 50. The application of the imaging device 100 is not limited to a specific product. For example, the imaging device 100 can be applied as a camera module mounted on a portable information terminal such as a smartphone, a device incorporated in an in-vehicle sensing module, and a device incorporated in a sensing module of an unmanned aircraft such as a drone or an unmanned surface vehicle (USV). The light absorber 10 may be applied to an ambient light sensor for detecting the ambient brightness of a device, etc., in which the light absorber 10 is mounted. [Example]

[0091] The present invention will be described in more detail with reference to examples. Note that the present invention is not limited to the following examples. First, the evaluation method of the optical filters according to each example and each comparative example will be described.

[0092] (Transmission spectrum measurement) Using a JASCO V-670 ultraviolet-visible-near-infrared spectrophotometer, the transmission spectra of the optical filters according to each example were measured at angles of incidence of 0°, 35°, 45°, and 55°. The transmission spectra of the optical filters according to Examples 1 to 3 are shown in Figs. 3A to 5C. Similarly, the transmission spectra of the optical filters according to each comparative example were measured at an angle of incidence of 0°. The results are shown in Figs. 6 to 9. The characteristic values ​​of each optical filter obtained from these transmission spectra are shown in Tables 7 to 9. The subscript "IA" in each item in Tables 7 to 9 indicates the angle of incidence [°].

[0093] (Thickness measurement) The thickness of the optical filter was measured using a laser displacement meter LK-H008 manufactured by Keyence Corporation. 7 Shown below.

[0094] Example 1 4.500 g of copper acetate monohydrate and 240 g of tetrahydrofuran (THF) were mixed and stirred for 3 hours to obtain a copper acetate solution. Next, 2.572 g of Plysurf A208N, a phosphate ester compound manufactured by Daiichi Kogyo Seiyaku Co., Ltd., was added to the resulting copper acetate solution and stirred for 30 minutes to obtain Solution A. 40 g of THF was added to 2.886 g of n-butylphosphonic acid and stirred for 30 minutes to obtain Solution B. Solution B was added to Solution A while stirring and stirred at room temperature for 1 minute. Next, 100 g of toluene was added to this solution and stirred at room temperature for 1 minute to obtain Solution C. Solution C was placed in a flask and heated in an oil bath (Tokyo Rikakikai Co., Ltd., Model: OSB-2100) while undergoing a solvent removal treatment using a rotary evaporator (Tokyo Rikakikai Co., Ltd., Model: N-1110SF). The oil bath temperature was adjusted to 105°C. After the solvent removal treatment, Solution D was removed from the flask. In this way, composition α containing a compound formed by phosphonic acid and a copper component was obtained. It was presumed that the compound formed by phosphonic acid and a copper component was dispersed as fine particles in the composition.

[0095] 5 g of BASF's benzotriazole-based UV absorber Tinuvin 326 was added to 95 g of toluene and stirred for 30 minutes to obtain a UV absorber-containing composition β-1. Tinuvin 326 contained 2-[5-Chloro-(2H)-Benzotriazol-2-yl]-4-methyl-6-(tert-butyl)phenol, which is represented by the following formula (b-1).

[0096] [ka]

[0097] Composition α, 2.0 g of Composition β-1, and 0.09 g of CAT-AC (manufactured by Shin-Etsu Chemical Co., Ltd.) containing an aluminum alkoxide compound were added to 8.80 g of silicone resin KR-300 (manufactured by Shin-Etsu Chemical Co., Ltd.) and stirred for 30 minutes to obtain a light-absorbing composition according to Example 1. The amounts of materials added in preparing the light-absorbing composition or the contents of specified components in the light-absorbing composition are shown in Table 1. The ratios of the component contents are also shown in Table 4. The average molecular weight of Plysurf A208N used as the phosphate ester was determined to be 632 g / mol.

[0098] 0.1 g of Daikin Industries' surface antifouling coating agent Optool DSX (active ingredient concentration: 20% by mass) and 19.9 g of 3M's hydrofluoroether-containing liquid Novec 7100 were mixed and stirred for 5 minutes to prepare a fluorine treatment agent (active ingredient concentration: 0.1% by mass). This fluorine treatment agent was applied to a borosilicate glass substrate (SCHOTT, product name: D263 T eco) measuring 130 mm x 100 mm x 0.70 mm by flow coating. The glass substrate was then left at room temperature for 24 hours to dry the coating of the fluorine treatment agent. The glass surface was then gently wiped with a dust-free cloth soaked in Novec 7100 to remove excess fluorine treatment agent. In this manner, a fluorine-treated substrate was prepared.

[0099] The light-absorbing composition according to Example 1 was applied to an 80 mm × 80 mm area in the center of one main surface of a fluorine-treated substrate using a dispenser to form a coating film. The resulting coating film was thoroughly dried at room temperature, then placed in an oven where the temperature was gradually increased from room temperature to 45°C to volatilize the solvent and proceed to dryness. Finally, the coating film was heat-treated at 85°C for 6 hours to completely volatilize the solvent and harden it. The coating film was then peeled off from the fluorine-treated substrate to obtain an optical filter according to Example 1 made of a film-like light absorber. The transmission spectra of the optical filter according to Example 1 at incident angles of 0° and 35°, 0° and 45°, and 0° and 55° are shown in Figures 3A, 3B, and 3C, respectively. Parameters obtained from the transmission spectra are also shown in Table 7.

[0100] <Example 2> 5.0 g of the benzotriazole-based UV absorber Tinuvin 234 manufactured by BASF was added to 95.0 g of toluene and stirred for 30 minutes to prepare a UV absorber-containing composition β-2. Tinuvin 234 contained Phenol, 2-(2H-Benzotriazol-2-yl)-4,6-bis(1-methyl-1-Phenylethyl) represented by the following formula (b-2). The light-absorbing composition of Example 2 was prepared in the same manner as Example 1, except that 3.6 g of Composition β-2 was added instead of 2.0 g of Composition β-1. Table 1 shows the amounts of materials added in the preparation of the light-absorbing composition, and the contents of specified components in the light-absorbing composition. Table 4 also shows the component content ratios.

[0101] [ka]

[0102] An optical filter according to Example 2 made of a film-like light absorber was produced in the same manner as in Example 1, except that the light-absorbing composition according to Example 2 was used instead of the light-absorbing composition according to Example 1. Examples at incident angles of 0° and 35°, incident angles of 0° and 45°, and incident angles of 0° and 55° 2 The transmission spectra of the optical filters according to the present invention are shown in Figures 4A, 4B, and 4C, respectively. Table 7 shows the parameters obtained from the transmission spectra.

[0103] Example 3 5.0 g of the benzotriazole-based UV absorber Tinuvin 329 manufactured by BASF was added to 95.0 g of toluene and stirred for 30 minutes to prepare a UV absorber-containing composition β-3. Tinuvin 329 contained 2Phenol,2-(2H-Benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl) represented by the following formula (b-3). The light-absorbing composition of Example 3 was prepared in the same manner as in Example 1, except that 4.0 g of composition β-3 was added instead of 2.0 g of composition β-1. Table 1 shows the amounts of materials added in the preparation of the light-absorbing composition and the contents of specified components in the light-absorbing composition. Table 4 also shows the ratios of the component contents.

[0104] [ka]

[0105] An optical filter according to Example 3 consisting of a film-like light absorber was produced in the same manner as in Example 1, except that the light-absorbing composition according to Example 3 was used instead of the light-absorbing composition according to Example 1. The transmission spectra of the optical filter according to Example 3 at incident angles of 0° and 35°, 0° and 45°, and 0° and 55° are shown in Figures 5A, 5B, and 5C, respectively. Furthermore, each parameter observed from the transmission spectrum is shown in Table 7.

[0106] Example 4 A light-absorbing composition according to Example 4 was prepared in the same manner as in Example 1, except that 0.025 g of aluminum isopropoxide (Al component content 13.21 mass%) manufactured by Tokyo Chemical Industry Co., Ltd. was added instead of CAT-AC containing aluminum alkoxide. The amounts of materials added in preparing the light-absorbing composition or the contents of specified components in the light-absorbing composition are shown in Table 2. The ratios of the component contents are also shown in Table 5.

[0107] An optical filter according to Example 4 consisting of a film-like light absorber was produced in the same manner as in Example 1, except that the light-absorbing composition according to Example 4 was used instead of the light-absorbing composition according to Example 1. For the optical filter according to Example 4, transmission spectra were measured at incident angles of 0°, 35°, 45°, and 55°. Table 8 shows the transmission spectra at incident angles of 0° and 55° and each parameter that can be seen from a comparison between them.

[0108] <Example 5> A light-absorbing composition according to Example 5 was prepared in the same manner as in Example 1, except that 0.038 g of Orgatix AL-3001 (Al content 10.7 mass%) manufactured by Matsumoto Fine Chemical Co., Ltd., containing aluminum tri-secondary butoxide, was added instead of CAT-AC containing aluminum alkoxide. The amounts of materials added in preparing the light-absorbing composition or the contents of specified components in the light-absorbing composition are shown in Table 2. The ratios of the component contents are also shown in Table 5.

[0109] An optical filter according to Example 5 consisting of a film-like light absorber was produced in the same manner as in Example 1, except that the light-absorbing composition according to Example 5 was used instead of the light-absorbing composition according to Example 1. For the optical filter according to Example 5, transmission spectra were measured at incident angles of 0°, 35°, 45°, and 55°. Table 8 shows the transmission spectra at incident angles of 0° and 55° and each parameter that can be seen from a comparison between them.

[0110] Example 6 A light-absorbing composition according to Example 6 was prepared in the same manner as in Example 1, except that 0.05 g of Orgatix TA-8 (Ti content 16.9 mass%) manufactured by Matsumoto Fine Chemical Co., Ltd., containing titanium tetraisopropoxide, was added instead of CAT-AC containing aluminum alkoxide. The amounts of materials added in preparing the light-absorbing composition or the contents of specified components in the light-absorbing composition are shown in Table 2. The ratios of the component contents are also shown in Table 5.

[0111] An optical filter according to Example 6 consisting of a film-like light absorber was produced in the same manner as in Example 1, except that the light-absorbing composition according to Example 6 was used instead of the light-absorbing composition according to Example 1. For the optical filter according to Example 6, transmission spectra were measured at incident angles of 0°, 35°, 45°, and 55°. Table 8 shows the transmission spectra at incident angles of 0° and 55° and each parameter that can be seen from a comparison between them.

[0112] Example 7 The light-absorbing composition of Example 7 was prepared in the same manner as in Example 2, except that 0.07 g of Orgatix TA-30 (Ti content 8.5 mass%) manufactured by Matsumoto Fine Chemical Co., Ltd., containing titanium tetra-2-ethylhexoxide, was added instead of CAT-AC containing aluminum alkoxide. The amounts of materials added in preparing the light-absorbing composition or the contents of specified components in the light-absorbing composition are shown in Table 2. The ratios of the component contents are also shown in Table 5.

[0113] An optical filter according to Example 7, which is made of a film-like light absorber, was produced in the same manner as in Example 2, except that the light-absorbing composition according to Example 7 was used instead of the light-absorbing composition according to Example 2. For the optical filter according to Example 7, transmission spectra were measured at incident angles of 0°, 35°, 45°, and 55°. Table 8 shows the transmission spectra at incident angles of 0° and 55° and each parameter that can be seen from a comparison between them.

[0114] Example 8 A light-absorbing composition according to Example 8 was prepared in the same manner as in Example 1, except that 0.06 g of Orgatix ZA-45 (Zr content: 21.0 mass%) manufactured by Matsumoto Fine Chemical Co., Ltd., containing zirconium tetra-normal-propoxide, was added instead of CAT-AC containing aluminum alkoxide. The amounts of materials added in preparing the light-absorbing composition or the contents of specified components in the light-absorbing composition are shown in Table 2. The ratios of the component contents are also shown in Table 5.

[0115] An optical filter according to Example 8, which is made of a film-like light absorber, was produced in the same manner as in Example 1, except that the light-absorbing composition according to Example 8 was used instead of the light-absorbing composition according to Example 1. For the optical filter according to Example 8, transmission spectra were measured at incident angles of 0°, 35°, 45°, and 55°. Table 8 shows the transmission spectra at incident angles of 0° and 55° and each parameter that can be seen from a comparison between them.

[0116] <Comparative Example 1> A light-absorbing composition according to Comparative Example 1 was prepared in the same manner as in Example 1, except that composition β-1 was not added. The amounts of materials added in preparing the light-absorbing composition or the contents of predetermined components in the light-absorbing composition are shown in Table 3. The ratios of the component contents are shown in Table 6.

[0117] An optical filter according to Comparative Example 1 made of a film-like light absorber was produced in the same manner as in Example 1, except that the light-absorbing composition according to Comparative Example 1 was used instead of the light-absorbing composition according to Example 1. The transmission spectrum of the optical filter according to Comparative Example 1 at an incident angle of 0° is shown in Fig. 6. Furthermore, each parameter that can be seen from the transmission spectrum is shown in Table 9.

[0118] <Comparative Example 2> 2.0 g of BASF's hydroxybenzophenone-based UV absorber Uvinul 3049 was added to 98.0 g of toluene and stirred for 30 minutes to prepare UV absorber-containing composition β-4. Uvinul 3049 contained a compound represented by the following formula (b-4). A light-absorbing composition according to Comparative Example 2 was prepared in the same manner as in Example 1, except that 5.0 g of composition β-4 was added instead of 2.0 g of composition β-1. The amounts of materials added in the preparation of the light-absorbing composition and the contents of specified components in the light-absorbing composition are shown in Table 3. The ratios of the component contents are also shown in Table 6.

[0119] [ka]

[0120] An optical filter according to Comparative Example 2 made of a film-like light absorber was produced in the same manner as in Example 1, except that the light-absorbing composition according to Comparative Example 2 was used instead of the light-absorbing composition according to Example 1. The transmission spectrum of the optical filter according to Comparative Example 2 at an incident angle of 0° is shown in Fig. 7. Furthermore, each parameter that can be seen from the transmission spectrum is shown in Table 9.

[0121] <Comparative Example 3> A composition containing an ultraviolet absorber was prepared by adding 2.0 g of the ultraviolet absorber Uvinul 3049 to 98.0 g of toluene and stirring for 30 minutes. 5.0 g of this composition was added to 10.0 g of silicone resin KR-300 manufactured by Shin-Etsu Chemical Co., Ltd. and stirring was continued for 30 minutes to obtain a light-absorbing composition according to Comparative Example 3. The amounts of materials added in the preparation of the light-absorbing composition and the contents of specified components in the light-absorbing composition are shown in Table 3. The ratios of the component contents are also shown in Table 6.

[0122] An optical filter according to Comparative Example 3 made of a film-like light absorber was produced in the same manner as in Example 1, except that the light-absorbing composition according to Comparative Example 3 was used instead of the light-absorbing composition according to Example 1. The transmission spectrum of the optical filter according to Comparative Example 3 at an incident angle of 0° is shown in Fig. 8. Furthermore, each parameter that can be seen from the transmission spectrum is shown in Table 9.

[0123] <Comparative Example 4> A composition containing an ultraviolet absorber was prepared by adding 2.0 g of the ultraviolet absorber Uvinul 3049 to 98.0 g of toluene and stirring for 30 minutes. 5.0 g of this composition and 0.10 g of aluminum alkoxide CAT-AC (manufactured by Shin-Etsu Chemical Co., Ltd.) were added to 10.0 g of silicone resin KR-300 (manufactured by Shin-Etsu Chemical Co., Ltd.) and stirring for 30 minutes to obtain a light-absorbing composition according to Comparative Example 4. The amounts of materials added in the preparation of the light-absorbing composition and the contents of specified components in the light-absorbing composition are shown in Table 3. The ratios of the component contents are also shown in Table 6.

[0124] An optical filter according to Comparative Example 4 made of a film-like light absorber was produced in the same manner as in Example 1, except that the light-absorbing composition according to Comparative Example 4 was used instead of the light-absorbing composition according to Example 1. The transmission spectrum of the optical filter according to Comparative Example 4 at an incident angle of 0° is shown in Fig. 9. Furthermore, each parameter that can be seen from the transmission spectrum is shown in Table 9.

[0125] As shown in Tables 7 and 8, the transmission spectra of the optical filters according to the examples showed that these optical filters had the desired transmittance characteristics. On the other hand, the transmission spectrum of the optical filter according to Comparative Example 1 at an incident angle of 0° showed that the wavelength λ at which the transmittance was 50% in the wavelength range of 350 nm to 450 nm was 0. 50 0(UV) is 354 nm, and T M (350-370) Therefore, it is difficult to say that the optical filter according to Comparative Example 1 has the desired transmittance characteristics.

[0126] According to the transmission spectrum of the optical filter according to Comparative Example 2 at an incident angle of 0°, λ 50 0(UV) was 443 nm. Therefore, it is difficult to say that the optical filter according to Comparative Example 2 has the desired transmittance characteristics. The ultraviolet absorber Uvinul 3049 used in producing the optical filter according to Comparative Example 2 contains both a hydroxy group and a carbonyl group in the molecule, and it is presumed that the original absorption wavelength of the ultraviolet absorber shifted to the longer wavelength side due to a partial reaction between the alkoxide compound containing a metal component as a catalyst and the ultraviolet absorber.

[0127] Comparative Examples 3 and 4 are examples for examining the difference in the transmission spectrum of an optical filter depending on whether or not aluminum alkoxide is present in the light-absorbing composition. The difference in light absorption characteristics of the optical filters according to Comparative Examples 3 and 4 is particularly evident at the wavelength λ where the transmittance is 50% in the wavelength range of 350 nm to 450 nm. 50 0(UV)In the optical filter according to Comparative Example 4, which contains both an ultraviolet absorber and aluminum alkoxide, the wavelength λ 50 0(UV) On the other hand, in the optical filter according to Comparative Example 3, which does not contain aluminum alkoxide, the wavelength λ 50 0(UV) From these results, it can be seen that when an ultraviolet absorber containing both a hydroxyl group and a carbonyl group in the molecule is contained together with an alkoxide compound containing a metal component such as aluminum alkoxide, the inherent properties of the ultraviolet absorber are changed.

[0128] Example 9 An optical filter according to Example 9 was fabricated by forming antireflection films on both principal surfaces of the optical filter according to Example 1 by a vacuum deposition method. The antireflection film was a dielectric multilayer film in which layers made of SiO2 and layers made of TiO2 were alternately stacked, with the number of layers being 9 and the film thickness being approximately 0.4 μm. The optical filter according to Example 9 includes the light absorber according to Example 1 and antireflection films formed on both principal surfaces of the light absorber. The transmission spectrum of the optical filter according to Example 9 at an incident angle of 0° is shown in FIG. 10. Furthermore, each parameter that can be seen from the transmission spectrum is shown in Table 8.

[0129] [Table 1]

[0130] [Table 2]

[0131] [Table 3]

[0132] [Table 4]

[0133] Table 5

[0134] Table 6

[0135] Table 7

[0136] Table 8

[0137] Table 9

Claims

1. A light absorber whose transmission spectrum at an incident angle of 0° satisfies the following conditions (I), (II), (III), (IV), (V), (VI), and (Ia): (I) The average transmittance in the wavelength range of 450 nm to 600 nm is 75% or more. (II) The first wavelength at which the transmittance is 50% in the wavelength range of 350 nm to 450 nm is 380 nm or more and 440 nm or less. (III) The second wavelength at which the transmittance is 50% in the wavelength range of 650 nm to 750 nm is 680 nm or more and 740 nm or less. (IV) The maximum transmittance in the wavelength range of 350 nm to 370 nm is 1% or less. (V) The maximum transmittance in the wavelength range of 800 nm to 900 nm is 5% or less. (VI) The maximum transmittance in the wavelength range of 1100 nm to 1200 nm is 5% or less. (Ia) The average transmittance T A 0(650-670) in the wavelength range of 650 nm to 670 nm is 70% or more.

2. The light absorber according to claim 1 , wherein the transmission spectrum further satisfies the following condition (VII): (VII) The transmittance at a wavelength of 750 nm is 7% or more.

3. The light absorber according to claim 1 or 2, wherein the transmission spectrum further satisfies the following condition (VIII): (VIII) The transmittance at a wavelength of 780 nm is 3% or more.

4. a transmission spectrum of the light absorber at an incident angle of 55° has a third wavelength at which the transmittance is 50% in a wavelength range of 350 nm to 450 nm; the absolute value of the difference between the third wavelength and the first wavelength is 12 nm or less; The light absorber according to any one of claims 1 to 3.

5. a transmission spectrum of the light absorber at an incident angle of 55° has a fourth wavelength at which the transmittance is 50% in a wavelength range of 650 nm to 750 nm; an absolute value of the difference between the fourth wavelength and the second wavelength is 24 nm or less; The light absorber according to any one of claims 1 to 4.

6. a light absorbing compound comprising a phosphonic acid and a copper component; and an ultraviolet absorber that absorbs at least a portion of ultraviolet light. The light absorber according to any one of claims 1 to 5.

7. The light absorber according to claim 6 , further comprising at least one of an alkoxide having a metal component and a hydrolyzate of an alkoxide having a metal component.

8. The light absorber according to claim 7 , wherein the ultraviolet absorber is a compound having neither a hydroxy group nor a carbonyl group in the molecule.

9. Items and The light absorber according to any one of claims 1 to 8 formed on a part of the surface of the article, An article with a light absorber.

10. An imaging device comprising the light absorber according to any one of claims 1 to 8.

11. 1. A light absorbing composition comprising: A light-absorbing composition, wherein a transmission spectrum at an incident angle of 0° of a light absorber obtained by curing the light-absorbing composition satisfies the following conditions (i), (ii), (iii), (iv), (v), (vi), and (ia): (i) The average transmittance in the wavelength range of 450 nm to 600 nm is 75% or more. (ii) The first wavelength at which the transmittance is 50% in the wavelength range of 350 nm to 450 nm is 380 nm or more and 440 nm or less. (iii) The second wavelength at which the transmittance is 50% in the wavelength range of 650 nm to 750 nm is 680 nm or more and 740 nm or less. (iv) The maximum transmittance in the wavelength range of 350 nm to 370 nm is 1% or less. (v) The maximum transmittance in the wavelength range of 800 nm to 900 nm is 5% or less. (vi) The maximum transmittance in the wavelength range of 1100 nm to 1200 nm is 5% or less. (ia) The average transmittance T A 0(650-670) in the wavelength range of 650 nm to 670 nm is 70% or more.

12. 12. The light-absorbing composition of claim 11, wherein the transmission spectrum further satisfies the following condition (vii): (vii) The transmittance at a wavelength of 750 nm is 7% or more.

13. 13. The light-absorbing composition according to claim 11 or 12, wherein the transmission spectrum further satisfies the following condition (viii): (viii) The transmittance at a wavelength of 780 nm is 3% or more.

14. a transmission spectrum of the light absorber at an incident angle of 55° has a third wavelength at which the transmittance is 50% in a wavelength range of 350 nm to 450 nm; the absolute value of the difference between the third wavelength and the first wavelength is 12 nm or less; The light-absorbing composition according to any one of claims 11 to 13.

15. a transmission spectrum of the light absorber at an incident angle of 55° has a fourth wavelength at which the transmittance is 50% in a wavelength range of 650 nm to 750 nm; an absolute value of the difference between the fourth wavelength and the second wavelength is 24 nm or less; The light-absorbing composition according to any one of claims 11 to 14.

16. a light absorbing compound comprising a phosphonic acid and a copper component; and an ultraviolet absorber that absorbs at least a portion of ultraviolet light. The light-absorbing composition according to any one of claims 11 to 15.

17. 17. The light-absorbing composition of claim 16, further comprising at least one of an alkoxide having a metal component and a hydrolyzate of an alkoxide having a metal component.

18. 18. The light-absorbing composition according to claim 17, wherein the ultraviolet absorber is a compound having neither a hydroxy group nor a carbonyl group in the molecule.

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