JP7510278B2 - Light absorber, article with light absorber, imaging device, and light absorbing composition - Google Patents

Description

The present invention relates to a light absorber, an article with a light absorber, an imaging device, and a light absorbing composition.

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. Generally, solid-state imaging elements have spectral sensitivity over a wide wavelength range from the ultraviolet to infrared regions. Meanwhile, human visual sensitivity exists only in the visible light region. For this reason, a technique is known in which an optical filter that blocks part of infrared or ultraviolet light is placed in front of the solid-state imaging element in order to bring the spectral sensitivity of the solid-state imaging element in the imaging device closer to the human visual sensitivity.

Conventionally, such optical filters have generally used a dielectric multilayer film to block infrared or ultraviolet rays. However, in recent years, optical filters with a film containing a light absorbent have been attracting attention. The transmittance characteristics of optical filters with a film containing a light absorbent are not easily affected by the angle of incidence, so good images with little change in color can be obtained even when light is incident on the optical filter at an angle in an imaging device. In addition, 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 with a film containing a light absorbent are also advantageous in terms of making imaging devices smaller and thinner.

As such a light absorbing agent, a light absorbing agent 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 absorbing agent formed from a phosphonic acid having a phenyl group or a halogenated phenyl group (phenyl-based phosphonic acid) and copper ions.

Patent Document 2 also describes an optical filter with a UV-IR absorbing layer capable of absorbing infrared and ultraviolet rays. The UV-IR absorbing layer contains a UV-IR absorbent formed of phosphonic acid and copper ions. In order for the optical filter to have 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 (alkyl-based phosphonic acid).

Patent Document 3 also describes an infrared cut filter that includes an organic dye-containing layer and a copper phosphonate-containing layer.

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 certain requirements in the spectral transmittance curve at an incident angle of 0°. The absorption layer contains a near-infrared absorbing dye such as a squarylium dye.

Patent No. 6339755 Patent No. 6232161 Patent No. 6281023 International Publication No. 2020/004641

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. Although this is advantageous from the viewpoint of blocking infrared rays well, it is difficult to say that it is advantageous from the viewpoint of increasing the transmittance in the red band. On the other hand, in the optical filter described in Patent Document 4, although the wavelength at which the 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 insufficient blocking of light by the absorbing layer. For this reason, in the optical filter described in Patent Document 4, a complicated process is required to form the reflective layer.

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 band, and that can effectively block near-infrared light.

The present invention relates to
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.

The present invention also provides a method for producing a method for manufacturing a semiconductor device comprising the steps of:
The goods,
The above-mentioned light absorber formed on a part of the surface of the article,
An article with a light absorber is provided.

The present invention also provides a method for producing a method for manufacturing a semiconductor device comprising the steps of:
1. A light absorbing composition comprising:
The present invention provides a light-absorbing composition, the transmission spectrum of a light-absorbing material obtained by curing the light-absorbing composition at an incident angle of 0° satisfying 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.

The above light absorber tends to have high transmittance in the visible light range, especially in the red light band. In addition, the above light absorber can effectively block near-infrared light.

FIG. 1A is a cross-sectional view showing an example of a light absorber according to the present invention. FIG. 1B is a cross-sectional view showing one example of an article with a light absorber according to the present invention. FIG. 1C is a cross-sectional view showing another example of an article with a light absorber according to the present invention. FIG. 1D is a cross-sectional view showing an example of an optical member including a light absorber according to the present invention. FIG. 2 is a diagram showing an example of an imaging device according to the present invention. FIG. 3A shows a transmission spectrum of the optical filter according to the first embodiment. FIG. 3B shows the transmission spectrum of the optical filter according to the first embodiment. FIG. 3C shows the transmission spectrum of the optical filter according to the first embodiment. FIG. 4A shows a transmission spectrum of the optical filter according to the second embodiment. FIG. 4B shows the transmission spectrum of the optical filter according to the second embodiment. FIG. 4C shows the transmission spectrum of the optical filter according to the second embodiment. FIG. 5A shows a transmission spectrum of the optical filter according to the third embodiment. FIG. 5B shows the transmission spectrum of the optical filter according to the third embodiment. FIG. 5C shows the transmission spectrum of the optical filter according to the third embodiment. FIG. 6 shows the transmission spectrum of the optical filter according to the first comparative example. FIG. 7 shows the transmission spectrum of the optical filter according to Comparative Example 2. FIG. 8 shows the transmission spectrum of the optical filter according to Comparative Example 3. FIG. 9 shows the transmission spectrum of the optical filter according to Comparative Example 4.

It is conceivable that a camera equipped with a CMOS sensor or the like may be mounted on a vehicle as part of an in-vehicle system. In addition, such a camera may be used in driving devices, moving devices, and transport devices, such as drones and autonomous robots. In this case, the camera mainly acquires information such as captured images of the external situation, and the acquired information may support the operation of the 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 rays. The visible light range is the range of wavelengths of electromagnetic waves that humans can recognize as light, with the lower limit of the wavelength range being 360 to 400 nm and the upper limit of the wavelength range being 760 to 830 nm. According to the Japanese Industrial Standards (JIS) Z 8120:2001, the visible light range may be in the range of 380 to 780 nm. Infrared light, particularly near infrared light (NIR), is defined as electromagnetic waves with wavelengths in the range of up to about 1400 nm, which is beyond the visible light wavelength range.

In traffic signals and road signs, etc., danger or safety indications may be displayed in red. For example, in addition to red traffic lights, traffic signs (road signs) such as no entry, stop, and slow down are examples of such indications. In the transmission spectrum of an optical filter, it is important that the transmittance in the wavelength range corresponding to red is high in order to accurately recognize surrounding objects, including the above-mentioned red traffic lights and regulatory signs. The red color displayed in regulatory signs, etc., has a low limit of 580 to 620 nm and a high reflectance in a wavelength range exceeding approximately 780 nm, depending on the specifications of the member such as the retroreflective sheet. Assuming that 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 a high transmittance in the wavelength range of 580 to 780 nm, a high transmittance in the wavelength range of 620 to 760 nm, or a high transmittance in the wavelength range of 620 to 750 nm.

In addition, the ability of the optical filter to effectively block infrared rays is important in order to prevent problems such as the camera not being able to capture a good image due to the influence of infrared sensing in vehicles, moving devices, or transport devices traveling in the vicinity. It is understood that the characteristics of the optical filter described in Patent Document 4 have been adjusted from this perspective. Meanwhile, the optical filter described in Patent Document 4 has a reflective layer in addition to an absorbing layer. For this reason, the inventors have undergone extensive trial and error in order to develop a technology that can increase the 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.

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

The following describes an embodiment of the present invention. Note that the following description is merely an example of the present invention, and the present invention is not limited to the following embodiment.

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) The average transmittance T ^A _0(450-600) in the wavelength range of 450 nm to 600 nm is 75% or more.
(II) The first wavelength λ ⁵⁰⁰ _(UV) 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 λ ⁵⁰⁰ _(IR) 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 T ^M _0(350-370) in the wavelength range of 350 nm to 370 nm is 1% or less.
(V) The maximum transmittance T ^M _0(800-900) in the wavelength range of 800 nm to 900 nm is 5% or less.
(VI) The maximum transmittance T ^M _0(1100-1200) in the wavelength range of 1100 nm to 1200 nm is 5% or less.

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

Regarding the 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) The average transmittance T ^A _0(650-670) in the wavelength range of 650 nm to 670 nm is 70% or more.

Regarding condition (Ia), the average value T ^A _0(650-670) is preferably 72% or more, and more preferably 74% or more.

Regarding condition (II), the first wavelength λ ⁵⁰⁰ _(UV) is preferably 385 nm or more and 420 nm or less, and more preferably 390 nm or more and 410 nm or less.

Regarding condition (III), the second wavelength λ ⁵⁰⁰ _(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.

Regarding condition (IV), the maximum value T ^M _0(350-370) is desirably 0.5% or less.

Regarding condition (V), the maximum value T ^M _0(800-900) is desirably 3% or less.

Regarding condition (VI), the maximum value T ^M _0(1100-1200) is desirably 3% or less.

The transmission spectrum of the light absorber 10 at the 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) The transmittance T ₀₍₇₅₀₎ at a wavelength of 750 nm is 7% or more.

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

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) The transmittance T ₀₍₇₈₀₎ at a wavelength of 780 nm is 3% or more.

Regarding condition (VIII), the transmittance T _{0 (780)} is desirably 4% or more, and more desirably 5% or more.

The transmission spectrum of the light absorber 10 at an incident angle of 55° has a third wavelength λ ⁵⁰ _{55 (UV)} at which the transmittance is 50% in the wavelength range of 350 nm to 450 nm, for example. The absolute value Δλ ⁵⁰ _{0/55 (UV} ) of the difference between the third wavelength λ ⁵⁰ 55 _(UV) and the first wavelength λ ⁵⁰ _{0 (UV)} is, for example, 12 nm or less. This makes it easy for the incidence angle dependency of the transmission spectrum of the light absorber 10 to be small. For this reason, for example, it is possible to suppress a change in color in the central and peripheral parts of an image obtained by an imaging device including the light absorber 10. In addition, it is possible to suppress a change 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 including 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.

The transmission spectrum of the light absorber 10 at an incident angle of 55° has a fourth wavelength λ ⁵⁰ _{55 (IR)} at which the transmittance is 50% in the wavelength range of 650 nm to 750 nm, for example. The absolute value Δλ ⁵⁰ _{0/55 (IR} ) of the difference between the fourth wavelength λ ⁵⁰ 55 _(IR) and the second wavelength λ ⁵⁰ _{0 (IR)} is, for example, 24 nm or less. This makes it easy for the incidence angle dependency of the transmission spectrum of the light absorber 10 to be small. For this reason, for example, it is possible to suppress a change in color in the central and peripheral parts of an image obtained by an imaging device including the light absorber 10. In addition, it is possible to suppress a change 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 including the light absorber 10. The absolute value Δλ ⁵⁰ _{0/55 (IR)} is preferably 20 nm or less, more preferably 18 nm or less, and even more preferably 16 nm or less.

The transmission spectrum of the light absorber 10 at an incident angle of 45° has, for example, a wavelength λ ⁵⁰ _45(UV) at which the transmittance is 50% in the wavelength range of 350 nm to 450 nm. The absolute value Δλ ⁵⁰ _0/45(UV) of the difference between the wavelength λ ⁵⁰ ₄₅₍ UV) and the first wavelength λ ⁵⁰ _0(UV) is, for example, 10 nm or less, preferably 8 nm or less, and more preferably 5 nm or less.

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

The transmission spectrum of the light absorber 10 at an incident angle of 45° has, for example, a wavelength λ ⁵⁰ _45(IR) at which the transmittance is 50% in the wavelength range of 650 nm to 750 nm. The absolute value Δλ ⁵⁰ _0/45(IR) of the difference between the wavelength λ ⁵⁰ ₄₅₍ IR) and the second wavelength λ ⁵⁰ _0(IR) is, for example, 18 nm or less, desirably 16 nm or less, and more desirably 12 nm or less.

The transmission spectrum of the light absorber 10 at an incident angle of 35° has, for example, a wavelength λ ⁵⁰ _35(IR) at which the transmittance is 50% in the wavelength range of 650 nm to 750 nm. The absolute value Δλ ⁵⁰ _0/35(IR) of the difference between the wavelength λ ⁵⁰ ₃₅₍ IR) and the second wavelength λ ⁵⁰ _0(IR) is, for example, 12 nm or less, desirably 10 nm or less, and more desirably 8 nm or less.

The light absorber 10 typically contains a predetermined light absorbing agent. The light absorbing agent 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 contains, for example, a light absorbing compound formed containing a phosphonic acid and a copper component, and an ultraviolet absorbing agent that absorbs at least a portion of ultraviolet light.

The phosphonic acid in the light absorbing compound 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), R ₁ 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 reach a wavelength of around 700 nm, and the light absorber 10 is likely to have the desired transmittance characteristics.

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.

The light absorber 10 further contains, for example, at least one of an alkoxide having a metal component and a hydrolyzate of an alkoxide having a metal component. The alkoxide compound containing at least one of an alkoxide having a metal component and a hydrolyzate of an alkoxide having a metal component can function as a catalyst to promote the curing of the light absorbing composition when the light absorbing composition contains a curable compound and the flowable light absorbing composition is cured to form the light absorber 10. The higher the temperature of the heat treatment when the light absorbing composition is cured by heat treatment, the easier it is to improve environmental resistance such as heat resistance. On the other hand, if the temperature of the heat treatment is high, the characteristics of some ultraviolet absorbers may be deteriorated. If the characteristics of the ultraviolet absorber are deteriorated, the wavelength of light absorbed by the ultraviolet absorber may deviate from the expected absorption wavelength. There is also a possibility that the absorption ability of the ultraviolet absorber may be deteriorated or disappear. However, when the light absorber 10 contains an alkoxide compound, the curing of the light absorbing composition can be promoted even if the temperature of the heat treatment is not high. As a result, the light absorber 10 is likely to have high environmental resistance.

The metal components contained in the alkoxide compound are not limited to specific components. Examples of the metal components are Al, Ti, Zr, Zn, Sn, and Fe. Examples of alkoxide compounds that can be used include CAT-AC, DX-9740, D-20, D-25, DX-175, D-15, and D-31. All of these are products of Shin-Etsu Chemical Co., Ltd.

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 hydroxyl group and a carbonyl group in the molecule, and when expressed by a structural formula, a compound that does not have both a hydroxyl group and a carbonyl group in one molecule. The curing of the light absorbing composition can be promoted by, for example, coordinating a reactant or precursor to a specific position in the molecule of an alkoxide having a metal component. For example, if there is a group that is easily coordinated by a substance other than the substance to be subjected to the reaction for curing the light absorbing composition, the action of the catalyst may be weakened. In particular, both the hydroxyl group and the carbonyl group have high electron donating properties, and the alkoxide compound reacts or coordinates with an ultraviolet absorber having these groups, and some of them form a complex, which may change the ultraviolet absorbing properties inherent to the ultraviolet 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 less likely to form a complex with the ultraviolet absorber, and the ultraviolet absorbing properties of the ultraviolet absorber are more likely to be exhibited. The ultraviolet absorber may contain only one of a hydroxy group and a carbonyl group in the molecule.

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 the light absorbing composition, and having excellent environmental resistance. Examples of UV absorbers are 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.

The light absorber 10 further contains, for example, a phosphate ester. The action of the phosphate ester makes it easy for the light absorbing compound to be appropriately dispersed in the light absorber 10. The phosphate ester may function as a dispersant for the light absorbing compound, or a part of the phosphate ester may react with the metal component to form a compound. For example, the phosphate ester may be coordinated to the light absorbing compound or may react with the compound, or may form a partial complex with the copper component.

The phosphate ester is not limited to a specific phosphate ester. The phosphate ester has, 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, or Plysurf A215C: polyoxyethylene tridecyl ether phosphate ester. All of these are products manufactured by Daiichi Kogyo Seiyaku Co., Ltd. In addition, 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. All of these are products manufactured by Nikko Chemicals Co., Ltd.

The light absorber 10 further contains, for example, a resin. 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 the conditions (I) to (VI). Examples of the resin are cyclic polyolefin resins, epoxy resins, polyimide resins, modified acrylic resins, silicone resins, and polyvinyl resins such as PVB. The resin in the light absorbing film 10 may be a cured product of a curable resin that can be cured by irradiation with energy such as heat or light.

The content of phosphonic acid and phosphoric acid ester in the light absorber 10 is not limited to a specific value. The ratio of the content of phosphonic acid to the content of phosphoric acid ester in the light absorber 10 is, for example, 1.0 to 3.0 on a mass basis. This suppresses hydrolysis of the phosphoric acid 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 copper component content to the phosphorus component content derived from the phosphonic acid and phosphate ester is not limited to a specific value. The ratio is, for example, 1 to 3, and preferably 1.5 to 2, on a mass basis.

The content of the alkoxide compound in the light absorber 10 is not limited to a specific value. As described above, the alkoxide compound acts as a catalyst to promote the curing of the light absorbing composition. The inclusion of a small amount of the alkoxide compound in the light absorbing composition can exert this catalytic action. The ratio of the phosphorus component content to the metal component content in the alkoxide compound is, for example, 5 to 5,000, and preferably 50 to 500, on a mass basis. The phosphorus component is typically derived from the light absorbing compound and the phosphate ester. On the other hand, the ratio of the copper component content to the metal component content in the alkoxide compound is, for example, 10 to 10,000, and preferably 100 to 1,000.

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, on a mass basis. 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, on a mass basis.

As shown in FIG. 1, the light absorber 10 is, for example, in the form of a film. In this specification, "film" is synonymous with a coating or layer. The light absorber 10 is not limited to being in the form of a film.

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, 500 μm or less, preferably 250 μm or less, more preferably 150 μm or less, and even more preferably 100 μm or less. A small thickness of the light absorber 10 is advantageous from the viewpoint of reducing the height of an imaging device equipped with the light absorber 10.

The light absorber 10 can be produced, for example, by curing a specific light absorbing 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 is not limited to a specific composition. The light absorbing composition contains, 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, the description of the light absorbing compound in the light absorber 10 can be referred to.

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.

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 hydroxyl group and a carbonyl group in the molecule. In other words, the ultraviolet absorber may be a compound that contains only one of a hydroxyl group and a carbonyl group.

The light absorbing composition further contains, for example, a phosphate ester. This makes it easier for the light absorbing compound to be properly dispersed in the light absorbing composition. With regard to the phosphate ester, the description of the phosphate ester in the light absorber 10 can be referred to.

The light absorbing composition further contains, for example, a curable resin. For the curable resin, please refer to the description of the resin in the light absorber 10.

In the preparation of 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, and copper citrate. For example, copper acetate monohydrate is represented as Cu(CH ₃ COO) _{2.H 2} O, and one mole of copper acetate monohydrate provides one mole of copper ion.

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 itself can be used independently as an optical filter by forming the light absorber 10 on the surface of an article and then peeling it off. The method for producing the light absorber 10 is not limited to a specific method. The light absorber 10 may be produced by a method such as casting, compression molding, vacuum molding, press molding, injection molding, blow molding, and extrusion molding.

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 a light absorber 10. The light absorber 10 covers at least a portion of the surface of the article 20.

The shape of the article 20 in the light absorber-attached 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, and a filter. The article 20 may be a solid-state imaging device, a window or windshield of a building or an automobile, a helmet, a light-transmitting shield such as goggles, or a display device such as a display and a screen. The surface of the article 20 covered by the light absorber 10 may be a flat surface, a curved surface, or a surface having irregularities.

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.

As shown in FIG. 1C, the dielectric multilayer film 30 may be formed on the light absorber-attached article 1a. In addition, as shown in FIG. 1D, the dielectric multilayer film 30 may be formed on the light absorber 10. In the dielectric multilayer film 30, for example, two or more types of dielectrics having different refractive indexes, such as SiO ₂ , TiO ₂ , MgF ₂ , and Ta ₂ O _5, are alternately laminated. The dielectric multilayer film 30 may exhibit light reflectivity or anti-reflection properties. A light shielding function may be exhibited by cooperation between the light absorber 10 and the dielectric multilayer film 30. For example, when the dielectric multilayer film 30 has light reflectivity, the burden required of the light absorber 10 in terms of light absorption characteristics can be reduced. Therefore, for example, the thickness of the light absorber 10 can be reduced. In addition, the content of the light absorbing composition or the content of the ultraviolet absorbing agent in the light absorber 10 can also be reduced.

A device including the light absorber 10 can be provided. The use of such a device is not limited to a specific use. Such a device is, for example, an in-vehicle camera and an in-vehicle sensor. In this case, since the light absorber 10 has a predetermined ultraviolet absorbing property, the image pickup element and the sensor element can be protected from ultraviolet rays. In addition, since the light absorber 10 has a high transmittance in the vicinity of a wavelength of 700 nm, the light absorber 10 can be used in a sensing system such as a light detection and ranging (Lidar) system using an infrared or red laser. Since the light absorber 10 has a high transmittance of light that belongs to the red color in particular, the device including the light absorber 10 is likely to have a high 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 the device including the light absorber 10. Furthermore, the Lidar system can be installed not only in devices for in-vehicle use, but also in portable information terminals such as smartphones.

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. The imaging device 100 can be applied, for example, as a camera module mounted on a portable information terminal such as a smartphone, a device incorporated in an on-board sensing module, and a device incorporated in a sensing module in 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 brightness of the surroundings of a device in which the light absorber 10 is mounted.

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.

(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 incident angles of 0°, 35°, 45°, and 55°. The results are shown in Figures 3A to 5C. Similarly, the transmission spectra of the optical filters according to each Comparative Example were measured at an incident angle of 0°. The results are shown in Figures 6 to 9. The characteristic values of each optical filter taken from these transmission spectra are shown in Table 3. The subscript "IA" in each item in Table 3 indicates the incident angle [°].

(Thickness measurement)
The thickness of the optical filter was measured using a laser displacement meter LK-H008 manufactured by Keyence Corp. The results are shown in Table 3.

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 a phosphoric acid ester compound Plysurf A208N manufactured by Daiichi Kogyo Seiyaku Co., Ltd. was added to the obtained copper acetate solution and stirred for 30 minutes to obtain a solution A. In addition, 40 g of THF was added to 2.886 g of n-butylphosphonic acid and stirred for 30 minutes to obtain a solution B. While stirring the solution A, solution B was added to the solution A and stirred at room temperature for 1 minute. Next, 100 g of toluene was added to this solution, and the solution was stirred at room temperature for 1 minute to obtain a solution C. This solution C was placed in a flask and heated in an oil bath (manufactured by Tokyo Rikakikai Co., Ltd., model: OSB-2100), while a solvent removal treatment was performed using a rotary evaporator (manufactured by Tokyo Rikakikai Co., Ltd., model: N-1110SF). The set temperature of the oil bath was adjusted to 105°C. Then, the D solution after the solvent removal treatment was taken out of the flask. In this way, a 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.

5 g of benzotriazole-based UV absorber Tinuvin 326 manufactured by BASF was added to 95 g of toluene and stirred for 30 minutes to obtain composition β-1 containing a UV absorber. 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).

Composition α, 2.0 g of composition β-1, and 0.09 g of aluminum alkoxide compound CAT-AC manufactured by Shin-Etsu Chemical Co., Ltd. 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 the light absorbing composition according to Example 1. The amounts of materials added in the preparation of the light absorbing composition or the contents of specific components in the light absorbing composition are shown in Table 1. The ratios of the contents of the components are also shown in Table 2. The average molecular weight of Plysurf A208N used as the phosphate ester was determined to be 632 g/mol.

0.1 g of the surface antifouling coating agent Optool DSX (active ingredient concentration: 20% by mass) manufactured by Daikin Industries, Ltd. and 19.9 g of hydrofluoroether-containing liquid Novec 7100 manufactured by 3M 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 by flow coating to borosilicate glass (manufactured by SCHOTT, product name: D263 T eco) having dimensions of 130 mm x 100 mm x 0.70 mm. The glass substrate was then left at room temperature for 24 hours to dry the coating of the fluorine treatment agent, and the glass surface was then lightly wiped with a dust-free cloth containing Novec 7100 to remove excess fluorine treatment agent. In this way, a fluorine-treated substrate was produced.

The light absorbing composition according to Example 1 was applied to an area of 80 mm x 80 mm in the center of one of the main surfaces of the fluorine-treated substrate using a dispenser to form a coating film. The obtained coating film was thoroughly dried at room temperature, then placed in an oven and the temperature was gradually increased in the range of room temperature to 45°C to volatilize the solvent and proceed to dry, and finally heat-treated at 85°C for 6 hours to completely volatilize the solvent and harden the film. 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.

Example 2
As an ultraviolet absorber, 5.0 g of benzotriazole ultraviolet absorber Tinuvin 234 manufactured by BASF was added to 95.0 g of toluene and stirred for 30 minutes to prepare a composition β-2 containing an ultraviolet absorber. Tinuvin 234 contained Phenol, 2-(2H-Benzotriazol-2-yl)-4,6-bis(1-methyl-1-Phenylethyl) represented by the following formula (b-2). A light-absorbing composition according to Example 2 was prepared in the same manner as in Example 1, except that 3.6 g of composition β-2 was added instead of 2.0 g of composition β-1 in the preparation of the light-absorbing composition. The amounts of materials added in the preparation of the light-absorbing composition or the contents of predetermined components in the light-absorbing composition are shown in Table 1. The ratio of the contents of the components is also shown in Table 2.

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. The transmission spectra of the optical filter according to Example 1 at angles of incidence of 0° and 35°, 0° and 45°, and 0° and 55° are shown in Figures 4A, 4B, and 4C, respectively.

Example 3
As an ultraviolet absorber, 5.0 g of benzotriazole ultraviolet absorber Tinuvin 329 manufactured by BASF was added to 95.0 g of toluene and stirred for 30 minutes to prepare a composition β-3 containing an ultraviolet absorber. Tinuvin 329 contained 2Phenol,2-(2H-Benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl) represented by the following formula (b-3). A light-absorbing composition according to 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 in the preparation of the light-absorbing composition. The amounts of materials added in the preparation of the light-absorbing composition or the contents of predetermined components in the light-absorbing composition are shown in Table 1. The ratio of the contents of the components is also shown in Table 2.

An optical filter according to 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 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.

<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 the preparation of the light-absorbing composition or the contents of predetermined components in the light-absorbing composition are shown in Table 1. The content ratios of the components are shown in Table 2.

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.

<Comparative Example 2>
As an ultraviolet absorber, 2.0 g of hydroxybenzophenone ultraviolet absorber Uvinul3049 manufactured by BASF was added to 98.0 g of toluene and stirred for 30 minutes to prepare composition β-4 containing an ultraviolet absorber. Uvinul3049 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 in the preparation of the light-absorbing composition. The amounts of materials added in the preparation of the light-absorbing composition or the contents of predetermined components in the light-absorbing composition are shown in Table 1. The ratio of the contents of the components is also shown in Table 2.

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.

<Comparative Example 3>
2.0 g of ultraviolet absorber Uvinul3049 was added to 98.0 g of toluene and stirred for 30 minutes to prepare a composition containing an ultraviolet absorber. 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 stirred 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 or the contents of predetermined components in the light absorbing composition are shown in Table 1. The ratio of the contents of the components is also shown in Table 2.

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.

<Comparative Example 4>
2.0 g of ultraviolet absorber Uvinul3049 was added to 98.0 g of toluene and stirred for 30 minutes to prepare a composition containing an ultraviolet absorber. 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 stirred for 30 minutes to obtain a light absorbing composition according to Comparative Example 4. The amount of material added in the preparation of the light absorbing composition or the content of a specific component in the light absorbing composition is shown in Table 1. The content ratio of the components is also shown in Table 2.

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.

As shown in Table 3, 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 ⁵⁰ _{0 (UV)} at which the transmittance was 50% in the wavelength range of 350 nm to 450 nm was 354 nm, and T ^M _(350-370) exceeded 70%. For this reason, it was difficult to say that the optical filter according to Comparative Example 1 had the desired transmittance characteristics.

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 the preparation of the optical filter according to Comparative Example 2 contains both a hydroxyl group and a carbonyl group in the molecule, and it is presumed that the original absorption wavelength of the ultraviolet absorber shifted to the long wavelength side due to a partial reaction between the alkoxide compound containing a metal component as a catalyst and the ultraviolet absorber.

Comparative Examples 3 and 4 are examples for examining the difference in the transmission spectrum of an optical filter caused by the presence or absence of an aluminum alkoxide in a light-absorbing composition. The difference in light absorption characteristics of the optical filters according to Comparative Examples 3 and 4 appeared particularly at the wavelength λ ⁵⁰ _{0 (UV)} at which the transmittance was 50% in the wavelength range of 350 nm to 450 nm. In the optical filter according to Comparative Example 4, which contains both an ultraviolet absorber and an aluminum alkoxide, the wavelength λ ⁵⁰ _{0 (UV)} was 444 nm. On the other hand, in the optical filter according to Comparative Example 3, which does not contain an aluminum alkoxide, the wavelength λ ⁵⁰ _{0 (UV)} was 400 nm. From these results, it can be understood 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 an aluminum alkoxide, the inherent properties of the ultraviolet absorber change.

REFERENCE SIGNS LIST 1a Article with light absorber 10 Light absorber 20 Article 30 Dielectric multilayer film 40 Lens system 50 Imaging element 100 Imaging device

Claims (12)

a light absorbing compound comprising a phosphonic acid and a copper component;
an ultraviolet absorbing agent that absorbs at least a portion of ultraviolet light;
At least one of an alkoxide having a metal component and a hydrolysate of an alkoxide having a metal component;
The ultraviolet absorber is a compound having either a hydroxyl group or a carbonyl group in the molecule,
A light absorber having a transmission spectrum at an incident angle of 0° that 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. 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. 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. 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. 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 a 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. The goods,
The light absorber according to any one of claims 1 to 5 formed on a part of the surface of the article,
An article with a light absorber. An imaging device equipped with a light absorber according to any one of claims 1 to 5. 1. A light absorbing composition comprising:
a light absorbing compound comprising a phosphonic acid and a copper component;
an ultraviolet absorbing agent that absorbs at least a portion of ultraviolet light;
At least one of an alkoxide having a metal component and a hydrolysate of an alkoxide having a metal component is contained,
The ultraviolet absorber is a compound having either a hydroxyl group or a carbonyl group in the molecule,
A light-absorbing composition, wherein a 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. 9. The light-absorbing composition of claim 8, wherein the transmission spectrum further satisfies the following condition (vii):
(vii) The transmittance at a wavelength of 750 nm is 7% or more. 10. The light-absorbing composition of claim 8, wherein the transmission spectrum further satisfies the following condition (viii):
(viii) The transmittance at a wavelength of 780 nm is 3% or more. 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 8 to 10. The 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 a difference between the fourth wavelength and the second wavelength is 24 nm or less;
The light absorbing composition according to any one of claims 8 to 11.

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