JP7344091B2 - Light-absorbing composition, light-absorbing film, and optical filter - Google Patents

Description

The present invention relates to a light-absorbing composition, a light-absorbing film, and an optical filter.

In imaging devices using solid-state image sensors such as CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor), various optical filters are placed in front of the solid-state image sensor to obtain images with good color reproducibility. has been done. In general, solid-state imaging devices have spectral sensitivity over a wide wavelength range from the ultraviolet region to the infrared region. On the other hand, human visibility exists only in the visible light region. For this reason, in order to bring the spectral sensitivity of a solid-state image sensor in an imaging device closer to the human visual sensitivity, a technique is known in which an optical filter is placed in front of the solid-state image sensor to block part of the infrared or ultraviolet light. .

Conventionally, such optical filters have generally utilized light reflection by a dielectric multilayer film to block infrared rays or ultraviolet rays. On the other hand, in recent years, optical filters equipped with a film containing a light absorber have attracted attention. The transmittance characteristics of an optical filter equipped with a film containing a light absorbing agent are not easily affected by the angle of incidence, so it is possible to produce good images with little change in color even when light enters the optical filter obliquely in an imaging device. Obtainable. In addition, a light-absorbing optical filter that does not use a light-reflecting film can suppress the occurrence of ghosts and flares caused by multiple reflections from the light-reflecting film, so it is possible to obtain good images when shooting backlit conditions or night scenes. Cheap. In addition, an optical filter including a film containing a light absorbing agent is advantageous in terms of making the imaging device smaller and thinner.

As such a light absorbent, a light absorbent formed from phosphonic acid and copper ions is known. For example, Patent Document 1 describes an optical filter that includes a light absorption layer containing a light absorption agent formed by a phosphonic acid having a phenyl group or a halogenated phenyl group (phenyl phosphonic acid) and copper ions. has been done.

Further, Patent Document 2 describes an optical filter including a UV-IR absorption layer capable of absorbing infrared rays and ultraviolet rays. The UV-IR absorbing layer contains UV-IR absorbers formed by phosphonic acid and copper ions. In order for the optical filter to satisfy predetermined optical properties, the UV-IR absorbing composition contains, for example, a phenyl phosphonic acid and a phosphonic acid having an alkyl group or a halogenated alkyl group (alkyl phosphonic acid). ing.

Further, Patent Document 3 describes an infrared cut filter including an organic dye-containing layer containing a predetermined organic dye and a copper phosphonate-containing layer.

International Publication No. 2018/088561 Patent No. 6232161 International Publication No. 2017/006571

The techniques described in Patent Documents 1 to 3 have room for reexamination from the viewpoint of absorption characteristics in a short wavelength region around a wavelength of 400 nm. Therefore, the present invention provides a light-absorbing composition, a light-absorbing film, and an optical filter that are advantageous from the viewpoint of absorption characteristics in a short wavelength region.

The present invention
phosphonic acid,
an ultraviolet absorber having a hydroxyl group and a carbonyl group in its molecule;
Contains a metal component and
A light-absorbing composition is provided.

Moreover, the present invention
phosphonic acid,
an ultraviolet absorber having a hydroxyl group and a carbonyl group in its molecule;
Contains a metal component and
Provides a light absorption film.

Further, the present invention provides an optical filter including the above-mentioned light absorption film.

The above-mentioned light-absorbing composition is advantageous from the viewpoint of absorption characteristics in a short wavelength region. In addition, the above light absorption film and the above optical filter are advantageous from the viewpoint of absorption characteristics in a short wavelength region.

FIG. 1 is a cross-sectional view showing an example of a light absorption film according to the present invention. FIG. 2 is a sectional view showing an example of an optical filter according to the present invention. FIG. 3 is a transmission spectrum of the optical filter according to Example 1. FIG. 4 is a transmission spectrum of the optical filter according to Example 2. FIG. 5 is a transmission spectrum of the optical filter according to Example 3. FIG. 6 is a transmission spectrum of the optical filter according to Example 4. FIG. 7 is a transmission spectrum of the optical filter according to Comparative Example 1. FIG. 8 is a transmission spectrum of the optical filter according to Comparative Example 2. FIG. 9 is a transmission spectrum of the optical filter according to Comparative Example 3. FIG. 10 is a transmission spectrum of the optical filter according to Comparative Example 4. FIG. 11 is a transmission spectrum of a transparent glass substrate. FIG. 12 is an LC-UV chromatograph of ethanol containing a fragment of the light-absorbing film according to Example 5. FIG. 13 is an absorption spectrum regarding the characteristic peaks in the LC-UV chromatograph shown in FIG. 12. FIG. 14 is a transmission spectrum of an ethanol solution in which the ultraviolet absorber was eluted from the fragment of the light-absorbing film according to Example 5. FIG. 15 shows transmission spectra of five types of ethanol solutions in which ultraviolet absorbers are dissolved at predetermined concentrations. FIG. 16 is a graph showing the relationship between the value tr obtained by dividing the minimum value of transmittance by the maximum value of transmittance and the concentration η [%] of the ultraviolet absorber, based on the transmission spectrum shown in FIG. 15. FIG. 17 is a transmission spectrum of an ethanol solution in which the ultraviolet absorber was eluted from the fragment of the light-absorbing film according to Comparative Example 5.

If an optical filter for an imaging device using a solid-state image sensor can effectively absorb light in a short wavelength region around 400 nm in addition to absorbing light in a long wavelength region such as infrared rays, then The value of optical filters increases. According to the optical filter described in Patent Document 1, the wavelength at which the spectral transmittance is 50% in the wavelength range of 350 nm to 450 nm is less than 400 nm. In addition, according to the optical filter described in Patent Document 2, the wavelength at which the spectral transmittance is 50% in the wavelength range of 350 nm to 450 nm is in the range of approximately 390 nm to 415 nm. According to these facts, it is hard to say that the optical filters described in Patent Documents 1 and 2 are advantageous from the viewpoint of effectively absorbing light in a short wavelength region around a wavelength of 400 nm. The infrared cut filter described in Patent Document 3 requires a plurality of light absorption layers including an organic dye-containing layer and a copper phosphonate-containing layer. Therefore, it is hard to say that the technique described in Patent Document 3 is advantageous from the viewpoint of simplifying the optical filter.

Therefore, the present inventors have conducted extensive studies to develop an advantageous light-absorbing composition from the viewpoint of effectively absorbing light in the short wavelength region around 400 nm while containing phosphonic acid and metal components. Ta. As a result of extensive trial and error, the present inventors have discovered that a light-absorbing composition containing a predetermined ultraviolet absorber in addition to phosphonic acid and a metal component effectively absorbs light in the short wavelength region. The present invention has been completed based on the new discovery that the invention is advantageous.

Embodiments of the present invention will be described below. It should be noted that the following description relates to illustrating the present invention, and the present invention is not limited to the following embodiments.

The light-absorbing composition according to the present invention contains phosphonic acid, an ultraviolet absorber having a hydroxyl group and a carbonyl group in its molecule, and a metal component. A light-absorbing film or an optical filter produced using a light-absorbing composition because the light-absorbing composition contains a phosphonic acid and a metal component as well as an ultraviolet absorber having a hydroxyl group and a carbonyl group in the molecule. tends to effectively absorb light in a wavelength region around 400 nm.

Advantageous conditions for UV absorbers include appropriate light absorption and transmission ranges, photochemical stability, low photosensitization to the extent that there is no effect within the range of use, and thermochemical Conditions include being stable. From this point of view, it is conceivable to utilize a hydrogen transfer reaction of a hydroxy group within a molecule (an intramolecular hydrogen abstraction reaction) due to photoexcitation as a mechanism of light absorption by an ultraviolet absorber. Examples of ultraviolet absorbers that exhibit such a mechanism include compounds such as hydroxybenzophenone, salicylic acid, hydroxyphenylbenzotriazole, hydroxyphenyltriazine, and substituted acrylonitrile. In hydroxybenzophenone and salicylic acid, a reaction involving the transfer of hydrogen between a hydroxy group and a carbonyl group contained within the molecule is involved in the absorption of light such as ultraviolet light. On the other hand, in hydroxyphenylbenzotriazole, hydroxyphenyltriazine, and substituted acrylonitrile, a reaction involving hydrogen transfer between a hydroxy group and a nitrogen atom contained in the molecule is involved in light absorption such as ultraviolet light. Since these ultraviolet absorbers have a hydroxyl group in their molecules, it is presumed that they partially interact with the coexisting metal component or hydrogen donor, such as complexation. In systems such as light-absorbing compositions containing ultraviolet absorbers and their cured products, there are cases in which the ultraviolet absorber having a hydroxy group exists alone, and cases in which the ultraviolet absorber having a hydroxy group is present in combination with a metal component or a hydrogen donor. Compare with coexisting cases. According to this comparison, differences occur in optical properties such as their light absorption spectra and their light transmission spectra, supporting the above speculation. In particular, in a light-absorbing film obtained by curing a light-absorbing composition containing phosphonic acid, an ultraviolet absorber having a hydroxyl group and a carbonyl group in the molecule, and a metal component, It was found that a phenomenon occurs in which the optical absorption band shifts to the longer wavelength side. Therefore, such a light absorption film is advantageous in effectively and appropriately absorbing light with a wavelength of around 400 nm. Note that when the optical absorption band shifts to the longer wavelength side or expands to the longer wavelength side, for example, the absorption maximum wavelength shifts to the longer wavelength side within the wavelength range of 300 nm to 500 nm in the transmission spectrum, or the transmittance increases by 50 nm. % (UV cutoff wavelength) may shift to the longer wavelength side. As described above, according to the light-absorbing composition of the present invention, the light-absorbing film that is a cured product of the light-absorbing composition, and the optical filter equipped with the light-absorbing film, the absorption properties inherent to the ultraviolet absorber can be improved. Adjusted to effectively absorb light in the short wavelength region. As a result, the spectral transmittance of such a light absorption film or optical filter tends to be more appropriate when used together with a solid-state image sensor or the like.

The arrangement of the hydroxy group and carbonyl group in the ultraviolet absorber is not limited to a specific arrangement. In the ultraviolet absorber, the hydroxy group and the carbonyl group are preferably spaced apart by 1 to 6 atoms. It is thought that this makes it easy for hydrogen to migrate between the hydroxyl group and the carbonyl group in the ultraviolet absorber. For this reason, a phenomenon in which the optical absorption band in the wavelength range of 300 to 500 nm is shifted toward longer wavelengths tends to occur effectively. As a result, the light-absorbing film obtained by curing the light-absorbing composition easily absorbs light with a wavelength of around 400 nm more reliably and effectively and appropriately.

In the transmission spectrum of the light-absorbing film obtained by curing the light-absorbing composition of the present invention at an incident angle of 0 degrees, the transmittance T ₄₀₀ at a wavelength of 400 nm, the transmittance T 550 at a wavelength of 550 nm, and the transmittance T ₅₅₀ at a wavelength of 800 nm. The transmittance T ₈₀₀ in , for example, satisfies the conditions of 8≦T ₅₅₀ /T ₄₀₀ and 8≦T ₅₅₀ /T ₈₀₀ . As a result, a light-absorbing film or optical filter made using a light-absorbing composition can exhibit high transmittance for visible light while appropriately absorbing ultraviolet and infrared rays in the wavelength region around the visible range. Cheap.

Transmittance T ₄₀₀ , transmittance T ₅₅₀ , and transmittance T ₈₀₀ preferably satisfy the conditions of 12≦T ₅₅₀ /T ₄₀₀ and 28≦T ₅₅₀ /T ₈₀₀ , more preferably 16≦T ₅₅₀ /T ₄₀₀ and The condition of 60≦T ₅₅₀ /T ₈₀₀ is satisfied.

The ultraviolet absorber is not limited to a specific ultraviolet absorber as long as it has a hydroxyl group and a carbonyl group in its molecule. The ultraviolet absorber is preferably a compound that does not easily aggregate even when mixed with phosphonic acid and metal components. Such ultraviolet absorbers include, for example, at least hydroxybenzophenone.

The ultraviolet absorber desirably contains a benzophenone compound represented by the following formula (A1). In this case, the light-absorbing film or optical filter produced using the light-absorbing composition more reliably tends to effectively absorb light in a short wavelength region around 400 nm.

In formula (A1), at least one of R ₁₁ , R ₁₂ , R ₂₁ , and R ₂₂ is a hydroxy group. In formula (A1), when R ₁₁ , R ₁₂ , R ₂₁ , or R ₂₂ is a functional group other than a hydroxy group, plural R ₁₁ , plural R ₁₂ , plural R ₂₁ , or plural R ₂₂ are At least one of R ₁₁ , R ₁₂ , R ₂₁ , and R ₂₂ may be absent.

When R ₁₁ , R ₁₂ , R ₂₁ , or R ₂₂ is a functional group other than a hydroxy group, the functional group is, for example, a carboxyl group, an aldehyde group, a halogen, an alkyl group having 1 to 12 carbon atoms, an alkyl group having 1 to 12 carbon atoms in which one or more hydrogen atoms have been substituted with a halogen atom, an alkoxy group having 1 to 12 carbon atoms, or one or more hydrogen atoms in which one or more hydrogen atoms have been substituted with a halogen atom; It may also be an alkoxy group having 1 to 12 carbon atoms.

The ultraviolet absorber desirably contains a benzophenone compound represented by the following formula (A2). In this case, the light-absorbing film or optical filter produced using the light-absorbing composition more reliably tends to effectively absorb light in a short wavelength region around 400 nm.

In formula (A2), R ₃₁ is a hydroxy group, a carboxyl group, an aldehyde group, a halogen, an alkyl group having 1 to 12 carbon atoms, or a 1 to 12 hydrogen atom in which one or more hydrogen atoms are substituted with a halogen atom. may be an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms in which one or more hydrogen atoms have been replaced with a halogen atom. . In formula (A2), R ₃₁ does not need to be present. In formula (A2), R ₄₁ and R ₄₂ are a hydroxy group, a carboxyl group, an aldehyde group, a halogen, an alkyl group having 1 to 12 carbon atoms, or a group in which one or more hydrogen atoms are substituted with a halogen atom. - an alkyl group having 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms in which one or more hydrogen atoms have been replaced with a halogen atom; It's okay. In formula (A2), R ₄₁ and R ₄₂ may not be present. In formula (A2), a plurality of R ₄₁ may be present, and a plurality of R ₄₂ may be present.

The benzophenone compound represented by formula (A1) or formula (A2) is not limited to a specific compound. The benzophenone compounds are, for example, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy- 4-methoxy-4'-chlorobenzophenone, 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxy-2'- A group consisting of carboxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-n-octoxybenzophenone, 2-hydroxy-5-chlorobenzophenone, and 2,4-dibenzoylresorcin At least one selected from

The phosphonic acid is not limited to any particular phosphonic acid. The light-absorbing composition may contain a single type of phosphonic acid, or may contain multiple types of phosphonic acids. Phosphonic acid is represented by the following formula (B), for example. In this case, the light-absorbing film or optical filter produced using the light-absorbing composition effectively absorbs light in a wavelength range longer than 750 nm, and more reliably absorbs light in a short wavelength range around 400 nm. Easy to absorb light effectively.

In formula (B), R ₃ is an alkyl group, a halogenated alkyl group in which at least one hydrogen atom in the alkyl group is substituted with a halogen atom, an aryl group, or an aryl group in which at least one hydrogen atom in the aryl group is substituted with a halogen atom. is a halogenated aryl group.

The phosphonic acid represented by formula (B) is not limited to a specific phosphonic acid. The phosphonic acids represented by formula (B) include methylphosphonic acid, ethylphosphonic acid, normal (n-)propylphosphonic acid, isopropylphosphonic acid, normal (n-)butylphosphonic acid, isobutylphosphonic acid, sec-butylphosphonic acid, It may be a phosphonic acid such as tert-butylphosphonic acid and phenylphosphonic acid, and at least one hydrogen atom in the above phosphonic acid such as bromomethylphosphonic acid, fluoroethylphosphonic acid, bromophenylphosphonic acid, and iodophenylphosphonic acid. may be substituted with a halogen atom.

The metal component is not limited to a specific metal component. The metal component is, for example, a copper component. In this case, the light-absorbing film or optical filter produced using the light-absorbing composition more reliably tends to effectively absorb light in a short wavelength region around 400 nm. In the light-absorbing composition, the metal component may exist as a metal ion, or may exist in the form of a complex with a predetermined compound. The source of the metal component is not limited to a particular compound. Sources of metal components are, for example, acetates, benzoates, formates, stearates, pyrophosphates, oxides, chlorides, hydroxides, or hydrated salts thereof.

In the light-absorbing composition, the ratio of the ultraviolet absorber content to the metal component content is not limited to a specific value. The ratio is, for example, 0.001 to 0.100, preferably 0.001 to 0.030, based on the amount of substance. As a result, the light-absorbing film or optical filter produced using the light-absorbing composition more reliably tends to effectively absorb light in the short wavelength range around 400 nm.

In the light-absorbing composition, the ratio of the ultraviolet absorber content to the phosphonic acid content is not limited to a specific value. The ratio is, for example, 0.1% to 5%, preferably 0.1% to 3%, and more preferably 0.1% to 1% on a mass basis. As a result, the light-absorbing film or optical filter produced using the light-absorbing composition more reliably tends to effectively absorb light in the short wavelength range around 400 nm.

In the light-absorbing composition, in addition to the reaction between the phosphonic acid and the metal component, a particulate light-absorbing agent may be formed by a reaction between the phosphonic acid, the metal component, and the ultraviolet absorber. For example, phosphonic acid-copper compounds formed from the reaction of phosphonic acid and a copper component are infrared absorbers. The average particle diameter of the particulate light absorber is, for example, 5 nm to 200 nm. If the average particle diameter of the fine particles is 5 nm or more, no special process is required to make the fine particles finer, and there is a small possibility that the structure of the fine particles containing at least the light absorber will be destroyed. Further, fine particles are well dispersed in the light-absorbing composition. In addition, when the average particle diameter of the fine particles is 200 nm or less, the influence of Mie scattering can be reduced, the transmittance of visible light can be improved in the light absorption film, and the contrast and haze of images taken with an imaging device can be improved. The deterioration of the characteristics can be suppressed. The average particle diameter of the fine particles is preferably 100 nm or less. In this case, since the influence of Rayleigh scattering is reduced, the transparency to visible light increases in the light-absorbing film formed using the light-absorbing composition. Further, the average particle diameter of the fine particles is more preferably 75 nm or less. In this case, the light-absorbing film produced using the light-absorbing composition has particularly high transparency to visible light. Note that the average particle diameter of the fine particles can be measured by a dynamic light scattering method.

The light-absorbing composition may further contain, for example, a phosphoric acid ester. Due to the action of the phosphoric acid ester, the light absorbing agent is easily dispersed appropriately in the light absorbing composition or the light absorbing film obtained by curing it. Further, in addition to the function of the phosphoric acid ester as a dispersant, a part of the phosphoric acid ester may react with a metal component to form a compound. Further, the phosphoric acid ester may further coordinate or react with the compound formed by the metal component and the phosphonic acid to form a compound. The light absorber may contain components of these compounds or copper salts thereof.

The phosphoric ester is, for example, a phosphoric ester having a polyoxyalkyl group. The phosphoric ester having a polyoxyalkyl group is not limited to a specific phosphoric ester. Phosphate esters having a polyoxyalkyl group are, for example, Plysurf A208N: polyoxyethylene alkyl (C12, C13) ether phosphate, Plysurf A208F: polyoxyethylene alkyl (C8) ether phosphate, Plysurf A208B : Polyoxyethylene lauryl ether phosphate, Plysurf A219B: Polyoxyethylene lauryl ether phosphate, Plysurf AL: Polyoxyethylene styrenated phenyl ether phosphate, Plysurf A212C: Polyoxyethylene tridecyl ether phosphoric acid Ester, or Plysurf A215C: polyoxyethylene tridecyl ether phosphate ester. These are all products manufactured by Daiichi Kogyo Seiyaku Co., Ltd. Further, the phosphoric acid ester is, for example, NIKKOL DDP-2: polyoxyethylene alkyl ether phosphoric acid ester, NIKKOL DDP-4: polyoxyethylene alkyl ether phosphoric acid ester, or NIKKOL DDP-6: polyoxyethylene alkyl ether phosphoric acid. It may also be an ester. These are all products manufactured by Nikko Chemicals. In the light-absorbing composition, the mass ratio of the phosphonic acid content to the phosphoric acid ester content is from 0.2 to 10.0, preferably from 0.3 to 8.0.

The light-absorbing composition may further contain a resin. The resin is preferably a transparent resin that exhibits high transmittance at least in the visible light range. For example, but not limited to these, acrylic resin, epoxy resin, polycarbonate resin, polyether resin, polyester resin, cyclic olefin resin, silicone resin, etc. are used as the resin.

The resin is preferably a silicone resin containing aryl groups such as phenyl groups. If the resin contained in the light absorption film is hard (rigid), as the thickness of the layer containing the resin increases, cracks are likely to occur due to curing shrinkage during the production of the light absorption film. When the resin is a silicone resin containing an aryl group, the light-absorbing film formed from the light-absorbing composition tends to have good crack resistance. Furthermore, silicone resins containing aryl groups tend to have high compatibility or dispersibility with phosphonic acid and ultraviolet absorbers, and are difficult to aggregate light absorbers. Specific examples of silicone resins include KR-255, KR-300, KR-2621-1, KR-211, KR-311, KR-216, KR-212, KR-251, and KR-5230. can. These are all silicone resins manufactured by Shin-Etsu Chemical Co., Ltd.

In the light-absorbing composition, the ratio of the content of the ultraviolet absorber to the solid content of the resin is not limited to a specific value. The ratio is, for example, 0.1% to 1.8%, preferably 0.2% to 1.5%, on a mass basis. This is advantageous from the viewpoint of suppressing the occurrence of problems such as deterioration in weather resistance or bleed-out.

The light-absorbing composition may further contain an alkoxysilane, if necessary. In this case, siloxane bonds (-Si-O-Si-) are formed by hydrolytic condensation of alkoxysilane, and the light absorption film tends to have a dense structure. The alkoxysilane may be a monomer, may be in the form of an oligomer or polymer that has undergone some degree of hydrolysis and polycondensation, or may be a mixture thereof.

As the monomer alkoxysilane, tetraethoxysilane, tetramethoxysilane, methyltrimethoxysilane, and ethyltrimethoxysilane are used from the viewpoints of easy availability, easy reaction control, film adhesion, film weather resistance, etc. Methoxysilane, methyltriethoxysilane, ethyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane, diethyldimethoxysilane, dimethyldiethoxysilane, diethyldiethoxysilane, 3-glycidoxypropyltrimethoxysilane , 3-glycidoxypropyltriethoxysilane, and 3-glycidoxypropylmethyldiethoxysilane. One or more types of alkoxysilane can be used within a range that does not affect the effects of the present invention.

When the light-absorbing composition contains these alkoxysilanes, it has the effect of suppressing the aggregation of the light-absorbing agent composed of phosphonic acid and metal components, reducing the amount of the phosphate ester compound that functions as a dispersant. can.

An example of a method for preparing a light-absorbing composition will be explained. A metal salt such as acetate is added to a predetermined solvent such as tetrahydrofuran (THF) and stirred to prepare liquid A, which is a solution of the metal salt. In preparing Solution A, a phosphoric acid ester may be added. Next, phosphonic acid is added to a predetermined solvent such as THF and stirred to prepare Solution B. When the light-absorbing composition contains multiple types of phosphonic acids, each phosphonic acid is added to a predetermined solvent such as THF and stirred to mix multiple preliminary solutions prepared for each type of phosphonic acid. Solution B may also be prepared by In preparing the B solution, an alkoxysilane may be added as necessary. The phosphonic acid used for preparing Solution B is, for example, a phosphonic acid having an aryl group or a halogenated aryl group. While stirring the A liquid, add the B liquid to the A liquid and stir for a predetermined time. Next, a predetermined solvent such as toluene is added to this solution and stirred to obtain liquid C. Next, a solvent removal process is performed for a predetermined period of time while heating Solution C to obtain Solution D. As a result, components generated by dissociation of a solvent such as THF and a metal salt such as acetic acid (boiling point: about 118° C.) are removed, and a light absorbent is produced by the phosphonic acid and the metal component. The temperature at which liquid C is heated is determined based on the boiling point of the component to be removed that has dissociated from the metal salt. In addition, in the solvent removal treatment, the solvent such as toluene (boiling point: about 110° C.) used to obtain liquid C also evaporates. Since it is desirable that this solvent remains to some extent in the light-absorbing composition, the amount of solvent to be added and the time for desolvation treatment can be determined from this point of view. Note that o-xylene (boiling point: about 144° C.) can also be used instead of toluene to obtain liquid C. In this case, since the boiling point of o-xylene is higher than that of toluene, the amount added can be reduced to about one quarter of the amount of toluene added.

If necessary, the H solution can be adjusted as follows. A metal salt such as acetate is added to a predetermined solvent such as THF and stirred to prepare liquid E, which is a solution of the metal salt. In preparing Solution E, a phosphoric acid ester may be added. Next, phosphonic acid is added to a predetermined solvent such as THF and stirred to prepare Solution F. The phosphonic acid used in the preparation of Solution F can be, for example, a phosphonic acid having an alkyl group or a halogenated alkyl group. While stirring the E solution, add the F solution to the E solution and stir for a predetermined time. Next, a predetermined solvent such as toluene is added to this solution and stirred to obtain liquid G. Next, while heating the G liquid, a desolvation process is performed for a predetermined period of time to obtain a H liquid. As a result, components generated by dissociation of a solvent such as THF and a metal salt such as acetic acid (boiling point: about 118° C.) are removed, and a light absorbent is produced by the phosphonic acid and the metal component. The temperature at which liquid G is heated is determined based on the boiling point of the component to be removed that has dissociated from the metal salt. In addition, in the solvent removal treatment, the solvent such as toluene (boiling point: about 110° C.) used to obtain the G liquid is also volatilized. Since it is desirable that this solvent remains to some extent in the light-absorbing composition, the amount of solvent to be added and the time for desolvation treatment can be determined from this point of view. Note that o-xylene (boiling point: about 144° C.) can also be used instead of toluene to obtain the G liquid. In this case, since the boiling point of o-xylene is higher than that of toluene, the amount added can be reduced to about one quarter of the amount of toluene added.

A UV absorber having a hydroxyl group and a carbonyl group in its molecule is added to a predetermined solvent such as toluene and stirred to obtain a U liquid. A light-absorbing composition can be prepared by mixing and stirring liquid U and liquid D together with a silicone resin if necessary. The light-absorbing composition can also be prepared by mixing and stirring liquid U, liquid D, and liquid H together with a silicone resin if necessary. Solution U may be added in the preparation of Solution D or Solution H. For example, liquid U may be added in the preparation of liquid C and liquid G.

For example, the light-absorbing film 10 shown in FIG. 1 can be provided using the light-absorbing composition. The light-absorbing film 10 is obtained, for example, by curing a coating film of a light-absorbing composition. The light absorption film 10 contains phosphonic acid, an ultraviolet absorber having a hydroxyl group and a carbonyl group in its molecule, and a metal component. Thereby, the light absorption film 10 tends to effectively absorb light in a short wavelength region around a wavelength of 400 nm.

In the ultraviolet absorber of the light absorption film 10, the hydroxy group and the carbonyl group are preferably arranged with 1 to 6 atoms apart. Thereby, the light absorption film 10 can more reliably easily absorb light with a wavelength of around 400 nm effectively and appropriately.

In the transmission spectrum of the light absorption film 10 at an incident angle of 0 degrees, the transmittance T ₄₀₀ at a wavelength of 400 nm, the transmittance T ₅₅₀ at a wavelength of 550 nm, and the transmittance T ₈₀₀ at a wavelength of 800 nm are 8≦T ₅₅₀ /T ₄₀₀ and satisfies the condition of 8≦T ₅₅₀ /T ₈₀₀ . Thereby, the light absorption film 10 can easily exhibit high transmittance to visible light while appropriately absorbing ultraviolet rays and infrared rays in the wavelength region around the visible light region.

In the light absorption film 10, the transmittance T ₄₀₀ , the transmittance T ₅₅₀ , and the transmittance T ₈₀₀ preferably satisfy the conditions of 12≦T ₅₅₀ /T ₄₀₀ and 28≦T ₅₅₀ /T ₈₀₀ , and more preferably 16≦ The conditions of T ₅₅₀ /T ₄₀₀ and 60≦T ₅₅₀ /T ₈₀₀ are satisfied.

The ultraviolet absorber in the light absorption film 10 includes, for example, a benzophenone compound represented by the above formula (A1). Thereby, the light absorption film 10 can more reliably and effectively absorb light in a short wavelength region around 400 nm.

The ultraviolet absorber in the light absorption film 10 desirably contains a benzophenone compound represented by the above formula (A2). Thereby, the light absorption film 10 can more reliably easily absorb light in a short wavelength region around 400 nm effectively.

The phosphonic acid in the light absorption film 10 is represented by the above formula (B), for example. Thereby, the light absorption film 10 effectively absorbs light in a wavelength range longer than 750 nm, and more reliably easily absorbs light in a short wavelength range around 400 nm.

The metal component in the light absorption film 10 is, for example, a copper component. In this case, the light absorption film 10 can more reliably and effectively absorb light in a short wavelength region around 400 nm.

The light absorption film 10 may further contain, for example, a phosphoric acid ester. Due to the action of the phosphoric acid ester, the light absorbent is easily dispersed appropriately in the light absorption film 10.

As shown in FIG. 1, for example, an optical filter 1a including a light absorption film 10 can be provided. The optical filter 1a can easily absorb light in a short wavelength region around a wavelength of 400 nm effectively.

In the transmission spectrum of the optical filter 1a at an incident angle of 0 degrees, the transmittance T ₄₀₀ at a wavelength of 400 nm, the transmittance T ₅₅₀ at a wavelength of 550 nm, and the transmittance T ₈₀₀ at a wavelength of 800 nm are, for example, 8≦T ₅₅₀ /T ₄₀₀ and satisfies the condition of 8≦T ₅₅₀ /T ₈₀₀ .

In the optical filter 1a, the transmittance T ₄₀₀ , the transmittance T ₅₅₀ , and the transmittance T ₈₀₀ preferably satisfy the conditions of 12≦T ₅₅₀ /T ₄₀₀ and 28≦T ₅₅₀ /T ₈₀₀ , and more preferably 16≦T. The conditions of ₅₅₀ /T ₄₀₀ and 60≦T ₅₅₀ /T ₈₀₀ are satisfied. Furthermore, in the optical filter 1a, the transmittance T ₄₀₀ , the transmittance T ₅₅₀ , and the transmittance T ₈₀₀ preferably satisfy the conditions of T ₅₅₀ /T ₄₀₀ ≦120 and T ₅₅₀ /T ₈₀₀ ≦1×10 ⁷ , for example. satisfies the conditions of T ₅₅₀ /T ₄₀₀ ≦100 and T ₅₅₀ /T ₈₀₀ ≦1×10 ⁶ .

In the transmission spectrum of the optical filter 1a at an incident angle of 0 degrees, the following (I), (II), (III), (IV), (V), (VI), (VII), and (VIII) are preferable. , (IX), and (X) are further satisfied. Thereby, the optical filter 1a can easily exhibit desired characteristics.
(I) The maximum transmittance T ^M _300-380 at a wavelength of 300 nm to 380 nm is 1% or less.
(II) Transmittance T ₄₀₀ at a wavelength of 400 nm is 20% or less.
(III) The UV cutoff wavelength λ ^UV _CF , which is the wavelength at which the transmittance is 50% in the wavelength range of 400 nm to 490 nm, satisfies the condition of 405 nm≦λ ^UV _CF ≦480 nm.
(IV) The average value of transmittance T ^A _480-580 at a wavelength of 480 nm to 580 nm is 78% or more.
(V) The IR cutoff wavelength λ ^IR _CF , which is the wavelength at which the transmittance is 50% in the wavelength range of 590 nm to 700 nm, satisfies the condition of 600 nm≦λ ^IR _CF ≦700 nm.
(VI) The average value of transmittance T ^A _700-750 at a wavelength of 700 nm to 750 nm is 10% or less.
(VII) The maximum transmittance T ^M _800-950 at a wavelength of 800 nm to 950 nm is 3% or less.
(VIII) The maximum transmittance T ^M _700-1000 at a wavelength of 700 nm to 1000 nm is 10% or less.
(IX) The maximum transmittance T ^M _700-1100 at a wavelength of 700 nm to 1100 nm is 15% or less.
(X) The maximum transmittance T ^M _700-1200 at a wavelength of 700 nm to 1200 nm is 20% or less.

Regarding the above condition (I), in the transmission spectrum of the optical filter 1a at an incident angle of 0 degrees, the maximum transmittance T ^M _300-385 in the wavelength range of 300 nm to 385 nm is preferably 1% or less, and more preferably The maximum transmittance T ^M _300-390 in the wavelength range of 300 nm to 390 nm is 1% or less.

Regarding the condition (II) above, the transmittance T ₄₀₀ is preferably 10% or less, more preferably 5% or less.

Regarding the above condition (III), the condition of 405 nm≦λ ^UV _CF ≦470 nm is preferably satisfied, and more preferably the condition of 405 nm≦λ ^UV _CF ≦460 nm is satisfied.

Regarding the above condition (IV), the average value T ^A _480-580 is preferably 82% or more.

Regarding the above condition (V), the condition of 620 nm≦λ ^IR _CF ≦680 nm is preferably satisfied.

Regarding the above condition (VI), the average value T ^A _700-750 is preferably 3% or less.

Regarding the above condition (VII), the maximum transmittance T ^M _800-950 is preferably 1% or less, more preferably 0.5% or less.

Regarding the above condition (VIII), the maximum transmittance T ^M _700-1000 is preferably 7% or less, more preferably 5% or less.

Regarding the above condition (IX), the maximum transmittance T ^M _700-1100 is preferably 10% or less, more preferably 5% or less.

Regarding the above condition (X), the maximum transmittance T ^M _700-1200 is preferably 15% or less, more preferably 10% or less.

The transmission spectrum of the optical filter 1a at an incident angle of 0 degrees may satisfy, for example, the following conditions (α), (β), and (γ).
(α) In the wavelength range of 300 nm to 450 nm, the difference λ ^RUV _1% between the maximum wavelength showing 1% transmittance and the minimum wavelength showing 1% transmittance is 90 nm or more.
⁽ β) The difference λ ^R _CF between the IR cutoff wavelength λ IR _CF and the UV cutoff wavelength λ ^UV _CF is 180 nm or more.
(γ) In the wavelength range of 700 nm to 1200 nm, the difference λ ^RIR _1% between the maximum wavelength showing 1% transmittance and the minimum wavelength showing 1% transmittance is 200 nm or more.

By satisfying the condition (α), the optical filter 1a can exhibit good ultraviolet absorption performance. By satisfying the condition (β), a sufficient amount of visible light can be received by a sensor such as a solid-state image sensor that receives light that has passed through the optical filter 1a. By satisfying the condition (γ), the optical filter 1a can exhibit good infrared absorption performance. Therefore, by satisfying the conditions (α), (β), and (γ), the optical filter 1a can exhibit good ability to absorb ultraviolet rays and ultraviolet rays, that is, good UV-IR absorption ability.

Regarding the condition (γ), the difference λ ^RIR _1% is preferably 300 nm or more, more preferably 350 nm or more.

The optical filter 1a is composed of a single light absorption film 10, for example. In this case, the optical filter 1a may be used separately from the image sensor or the optical component, for example. The optical filter 1a may be bonded to an image sensor and an optical component. On the other hand, the optical filter 1a may be configured by applying the above-mentioned light-absorbing composition to an image sensor or an optical component and curing the light-absorbing composition.

The thickness of the light absorption film 10 is not limited to a specific value. The thickness of the light absorption film 10 is, for example, 10 μm to 600 μm, may be 20 μm to 400 μm, or may be 30 μm to 300 μm.

The optical filter 1a can be manufactured, for example, by peeling off the light absorption film 10 formed on the substrate from the substrate. In this case, the material of the substrate may be glass, resin, or metal. The surface of the substrate may be subjected to surface treatment such as coating with a fluorine-containing compound.

The optical filter 1a may be modified, for example, like the optical filter 1b shown in FIG. The optical filter 1b is configured in the same manner as the optical filter 1a, unless otherwise specified. Components of the optical filter 1b that are the same as or correspond to the components of the optical filter 1a are given the same reference numerals, and detailed description thereof will be omitted. The explanation regarding the optical filter 1a also applies to the optical filter 1b unless there is a technical contradiction.

As shown in FIG. 2, the optical filter 1b includes a light absorption film 10 and a transparent dielectric substrate 20. The light absorption film 10 is formed parallel to one main surface of the transparent dielectric substrate 20. The light absorption film 10 may be in contact with one main surface of the transparent dielectric substrate 20, for example. In this case, the light-absorbing film 10 can be formed, for example, by applying the above-mentioned light-absorbing composition onto one main surface of the transparent dielectric substrate 20 and curing the light-absorbing composition.

The type of transparent dielectric substrate 20 is not limited to a specific type. The transparent dielectric substrate 20 may have absorption ability in the infrared region. The transparent dielectric substrate 20 may have an average spectral transmittance of 90% or more in the wavelength range of 350 nm to 900 nm, for example. The material of the transparent dielectric substrate 20 is not limited to a specific material, but may be, for example, a predetermined glass or resin. When the material of the transparent dielectric substrate 20 is glass, the transparent dielectric substrate 20 is, for example, a transparent glass made of silicate glass such as soda lime glass and borosilicate glass, or a colored glass such as Cu and Co. It can be a phosphate glass and a fluorophosphate glass containing components. Phosphate glass and fluorophosphate glass containing a coloring component are, for example, infrared absorbing glasses and have light absorbing properties themselves. When the light absorption film 10 is used together with the transparent dielectric substrate 20 made of infrared absorbing glass, the light absorption and transmission spectra of both can be adjusted to produce an optical filter having desired optical characteristics. High degree of freedom in design.

When the material of the transparent dielectric substrate 20 is a resin, the resin may be, for example, a cyclic olefin resin such as a norbornene resin, a polyarylate resin, an acrylic resin, a modified acrylic resin, a polyimide resin, a polyetherimide resin, or a polysulfone resin. resin, polyether sulfone resin, polycarbonate resin, or silicone resin.

Each of the optical filters 1a and 1b may be modified to further include other functional films such as an infrared reflective film and an antireflection film. Such a functional film may be formed on the light absorption film 10 or the transparent dielectric substrate 20. For example, by providing an optical filter with an antireflection film, the transmittance in a predetermined wavelength range (eg, visible light range) can be increased. The antireflection coating may be constructed as a layer of a low refractive index material such as MgF ₂ and SiO ₂ , or a laminate of a layer of such a low refractive index material and a layer of a high refractive index material such as TiO ₂ . It may be configured as a dielectric multilayer film. Such an antireflection film can be formed by a method involving a physical reaction, such as vacuum deposition and sputtering, or a method involving a chemical reaction, such as a CVD method or a sol-gel method.

The optical filter may be configured, for example, with the light absorption film 10 disposed between two plates of glass. This improves the rigidity and mechanical strength of the optical filter. In addition, the main surface of the optical filter is hard, which is advantageous from the standpoint of preventing scratches. This advantage is particularly important when a relatively flexible resin is used as the binder or matrix in the light-absorbing film 10.

Examples will explain the present invention in more detail. Note that the present invention is not limited to the following examples.

<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, 1.646 g of Plysurf A208N (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), a phosphate ester compound, was added to the resulting copper acetate solution and stirred for 30 minutes to obtain liquid 1-A. . 40 g of THF was added to 0.706 g of phenylphosphonic acid and stirred for 30 minutes to obtain a 1-B1 solution. 40 g of THF was added to 4.230 g of 4-bromophenylphosphonic acid and stirred for 30 minutes to obtain liquid 1-B2. Next, 1-B1 liquid and 1-B2 liquid were mixed and stirred for 1 minute, and 8.664 g of methyltriethoxysilane (MTES) (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KBE-13) and tetraethoxysilane were added. (TEOS) (Special Grade, manufactured by Kishida Chemical Co., Ltd.) (2.830 g) was added to this mixed solution, and the mixture was further stirred for 1 minute to obtain Solution 1-B. Solution 1-B was added to solution 1-A while stirring solution 1-A, and the mixture was stirred at room temperature for 1 minute. Next, 140 g of toluene was added to this solution, and the mixture was stirred at room temperature for 1 minute to obtain liquid 1-C. 1-C liquid was put into a flask and heated in an oil bath (manufactured by Tokyo Rika Kikai Co., Ltd., model: OSB-2100), while the solvent was removed using a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd., model: N-1110SF). I did it. The set temperature of the oil bath was adjusted to 105°C. Thereafter, the liquid after the solvent removal treatment was taken out of the flask to obtain liquid 1-D. In this way, a 1-D liquid containing an aryl phosphonic acid, a copper component, and a phosphoric acid ester was obtained.

0.12 g of UV absorber Uvinul 3049 (manufactured by BASF, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone) and 99.88 g of toluene were mixed and stirred for 30 minutes to prepare the UV absorber. A 1-U solution containing the following was obtained.

4.500 g of copper acetate monohydrate and 240 g of 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, was added to the obtained copper acetate solution and stirred for 30 minutes to obtain liquid 1-E. 40 g of THF was added to 2.886 g of n-butylphosphonic acid and stirred for 30 minutes to obtain a 1-F solution. While stirring Solution 1-E, Solution 1-F was added, and the mixture was further stirred at room temperature for 1 minute. Next, 1-U solution containing an ultraviolet absorber was added to this solution, and the mixture was stirred at room temperature for 1 minute to obtain 1-G solution. Solution 1-G was placed in a flask and heated in an oil bath, while solvent removal was performed using a rotary evaporator. The set temperature of the oil bath was adjusted to 105°C. Thereafter, the solution after the solvent removal treatment was taken out of the flask to obtain a 1-H solution. In this way, a 1-H solution containing an alkyl phosphonic acid, a copper component, a phosphoric acid ester, and an ultraviolet absorber was obtained.

8.800 g of silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KR-300) was added to Liquid 1-D, and the mixture was stirred for 30 minutes to obtain Liquid 1-I. An amount corresponding to 40% by mass of the total amount of 1-H solution was added to 1-I solution, and stirring was further performed for 30 minutes to obtain a light-absorbing composition according to Example 1. The light-absorbing composition according to Example 1 contains an aryl phosphonic acid, an alkyl phosphonic acid, a copper component, a phosphoric acid ester, an alkoxysilane or a hydrolyzate thereof, and a polymerizable resin (silicone resin). , and an ultraviolet absorber. Table 1 shows the content of each component in the light-absorbing composition according to Example 1. In Table 1, the ratio of the content of the ultraviolet absorber to the solid content of the resin was calculated on the premise that the solid content of the resin was 50% by mass.

A dispenser was used in a 40 mm x 40 mm area at the center of one main surface of a transparent glass substrate made of borosilicate glass (manufactured by SCHOTT, product name: D263 T eco) having dimensions of 76 mm x 76 mm x 0.21 mm. The light-absorbing composition according to Example 1 was applied to form a coating film. After sufficiently drying the obtained coating film at room temperature, it was placed in an oven and heat-treated at 45°C for 2 hours and at 85°C for 30 minutes to volatilize the solvent and harden the coating film. Further, the transparent glass substrate was placed in an environment of 85° C. and 85% relative humidity for about 2 hours to promote the hydrolysis reaction of the alkoxysilane. In this way, the light absorption film according to Example 1 was formed, and the optical filter according to Example 1 was obtained.

(Transmission spectrum measurement)
The transmission spectrum of the optical filter according to Example 1 at an incident angle of 0° was measured using an ultraviolet-visible near-infrared spectrophotometer (manufactured by JASCO Corporation, product name: V-670). FIG. 3 shows the transmission spectrum of the optical filter according to Example 1. Further, Tables 2, 3, and 4 show the characteristics related to transmittance read from FIG. 3. From these results, the transmittance of the optical filter according to Example 1 at 400 nm is 5% or less, and the optical filter according to Example 1 has desirable absorption characteristics for light in the short wavelength region including ultraviolet rays. It was confirmed that the material had good optical properties. For reference, FIG. 11 shows the transmission spectrum of D263 Teco used as a transparent glass substrate.

(thickness measurement)
The distance to the surface of the optical filter was measured using a laser displacement meter (manufactured by Keyence Corporation, product name: LK-H008), and the thickness of the light absorption film was calculated by subtracting the thickness of the transparent glass substrate. The results are shown in Table 2.

<Example 2>
Instead of the 1-U liquid used in the preparation of the light-absorbing composition according to Example 1, it contains an ultraviolet absorber prepared by mixing 0.04 g of Uvinul 3049 (manufactured by BASF) and 99.96 g of toluene. A light-absorbing composition according to Example 2 was prepared in the same manner as in Example 1, except that the 2-U liquid was used, and a light-absorbing film was formed to produce an optical filter according to Example 2. did. The transmission spectrum of the optical filter according to Example 2 at an incident angle of 0° was measured in the same manner as in Example 1. In addition, the thickness of the light absorption film in the optical filter according to Example 2 was calculated in the same manner as in Example 1. FIG. 4 shows the transmission spectrum of the optical filter according to Example 2 at an incident angle of 0°. Tables 2 to 4 show each parameter that can be seen from the transmission spectrum in FIG. 4 and the thickness of the light absorption film. From these results, the transmittance at 400 nm of the optical filter according to Example 2 is 5% or less, and the optical filter according to Example 2 has desirable absorption performance for light in the short wavelength region including ultraviolet rays. It was confirmed that the material had good optical properties.

<Example 3>
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, 1.646 g of Plysurf A208N, which is a phosphate ester compound, was added to the obtained copper acetate solution and stirred for 30 minutes to obtain liquid 3-A. 40 g of THF was added to 0.706 g of phenylphosphonic acid and stirred for 30 minutes to obtain a 3-B1 solution. 40 g of THF was added to 4.230 g of 4-bromophenylphosphonic acid and stirred for 30 minutes to obtain liquid 3-B2. Next, 3-B1 liquid and 3-B2 liquid were mixed and stirred for 1 minute, and 8.664 g of methyltriethoxysilane (MTES) (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KBE-13) and tetraethoxysilane were added. (TEOS) (special grade, manufactured by Kishida Chemical Co., Ltd.) (2.830 g) was added to this mixed liquid, and the mixture was further stirred for 1 minute to obtain liquid 3-B. Solution 3-B was added to solution 3-A while stirring solution 3-A, and the mixture was stirred at room temperature for 1 minute. Next, 140 g of toluene was added to this solution, and the mixture was stirred at room temperature for 1 minute to obtain liquid 3-C. 3-C put the liquid in a flask and while heating it in an oil bath (manufactured by Tokyo Rikakikai Co., Ltd., model: OSB-2100), remove the solvent using a rotary evaporator (manufactured by Tokyo Rikakikai Co., Ltd., model: N-1110SF). I did it. The set temperature of the oil bath was adjusted to 105°C. Thereafter, the liquid after the solvent removal treatment was taken out of the flask to obtain a 3-D liquid. In this way, a 3-D liquid containing an aryl phosphonic acid, a copper component, and a phosphoric acid ester was obtained.

5 g of UV absorber Uvinul 3050 (manufactured by BASF, 2,2',4,4'-tetrahydroxybenzophenone) and 95 g of ethanol were mixed and stirred for 30 minutes to obtain 3-U containing the UV absorber. I got the liquid.

4.500 g of copper acetate monohydrate and 240 g of 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, was added to the obtained copper acetate solution and stirred for 30 minutes to obtain liquid 3-E. 40 g of THF was added to 2.886 g of n-butylphosphonic acid and stirred for 30 minutes to obtain a 3-F solution. Solution 3-F was added to solution 3-E while stirring solution 3-E, and the mixture was stirred at room temperature for 1 minute. Next, 100 g of toluene was added to this solution, and the mixture was stirred at room temperature for 1 minute to obtain liquid 3-G. The 3-G solution was placed in a flask and heated in an oil bath, while solvent removal was performed using a rotary evaporator. The set temperature of the oil bath was adjusted to 105°C. Thereafter, the 3-H solution after the solvent removal treatment was taken out of the flask to obtain a 3-H solution. In this way, a 3-H solution containing an alkyl phosphonic acid, a copper component, and a phosphoric acid ester was obtained.

8.800 g of silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KR-300) was added to the 3-D solution and stirred for 30 minutes to obtain a 3-I solution. An amount equivalent to 40% by mass of the total amount of 3-H solution was added to 3-I solution, and 0.96 g of 3-U solution containing an ultraviolet absorber was added and stirred for 30 minutes. A light-absorbing composition was obtained. The light-absorbing composition according to Example 3 contains an aryl phosphonic acid, an alkyl phosphonic acid, a copper component, a phosphoric acid ester, an alkoxysilane or a hydrolyzate thereof, and a polymerizable resin (silicone resin). , and an ultraviolet absorber.

A dispenser was used in a 40 mm x 40 mm area at the center of one main surface of a transparent glass substrate made of borosilicate glass (manufactured by SCHOTT, product name: D263 T eco) having dimensions of 76 mm x 76 mm x 0.21 mm. The light-absorbing composition according to Example 3 was applied to form a coating film. After sufficiently drying the obtained coating film at room temperature, it was placed in an oven and heat-treated at 45°C for 2 hours and at 85°C for 30 minutes to volatilize the solvent and harden the coating film. Further, the transparent glass substrate was placed in an environment of 85° C. and 85% relative humidity for about 2 hours to promote the hydrolysis reaction of the alkoxysilane. In this way, a light absorption film according to Example 3 was formed, and an optical filter according to Example 3 was obtained. The transmission spectrum of the optical filter according to Example 3 at an incident angle of 0° was measured in the same manner as in Example 1. In addition, the thickness of the light absorption film in the optical filter according to Example 3 was calculated in the same manner as in Example 1. FIG. 5 shows the transmission spectrum of the optical filter according to Example 3 at an incident angle of 0°. Tables 2 to 4 show each parameter that can be seen from the transmission spectrum in FIG. 5 and the thickness of the light absorption film. From these results, the transmittance at 400 nm of the optical filter according to Example 3 is 5% or less, and the optical filter according to Example 3 has desirable absorption performance for light in the short wavelength region including ultraviolet rays. It was confirmed that the material had good optical properties.

<Example 4>
Instead of the 3-U liquid used in the preparation of the light-absorbing composition according to Example 3, an ultraviolet absorber prepared by mixing 1.67 g of Uvinul 3050 (manufactured by BASF) and 98.33 g of toluene was used. A light-absorbing composition according to Example 4 was prepared in the same manner as in Example 3, except that the 4-U liquid containing Created. The transmission spectrum of the optical filter according to Example 4 at an incident angle of 0° was measured in the same manner as in Example 1. In addition, the thickness of the light absorption film in the optical filter according to Example 4 was calculated in the same manner as in Example 1. FIG. 6 shows the transmission spectrum of the optical filter according to Example 4 at an incident angle of 0°. Tables 2 to 4 show each parameter that can be seen from the transmission spectrum in FIG. 6 and the thickness of the light absorption film. From these results, the transmittance of the optical filter according to Example 4 at 400 nm is 5% or less, and the optical filter according to Example 4 has desirable absorption performance for light in the short wavelength region including ultraviolet rays. It was confirmed that the material had good optical properties.

<Comparative example 1>
0.250 g of UV absorber Uvinul 3049 (manufactured by BASF) and 12.25 g of toluene were mixed and stirred for 30 minutes to dissolve the UV absorber. Thereafter, 25.000 g of silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KR-300) was added to the solution and stirred for 30 minutes to obtain an ultraviolet absorbing composition according to Comparative Example 1.

A dispenser was used in a 40 mm x 40 mm area at the center of one main surface of a transparent glass substrate made of borosilicate glass (manufactured by SCHOTT, product name: D263 T eco) having dimensions of 76 mm x 76 mm x 0.21 mm. Then, the ultraviolet absorbing composition according to Comparative Example 1 was applied to form a coating film. The resulting coating film was placed in an oven and heat treated at 45° C. for 2 hours and at 85° C. for 1 hour to volatilize the solvent and cure the coating film. In this way, a light absorption film according to Comparative Example 1 was formed, and an ultraviolet absorption filter according to Comparative Example 1 was obtained.

The transmission spectrum of the ultraviolet absorption filter according to Comparative Example 1 at an incident angle of 0° was measured in the same manner as in Example 1. In addition, the thickness of the light absorption film in the ultraviolet absorption filter according to Comparative Example 1 was calculated in the same manner as in Example 1. FIG. 7 shows the transmission spectrum of the ultraviolet absorption filter according to Comparative Example 1 at an incident angle of 0°. Tables 2 to 4 show each parameter that can be seen from the transmission spectrum in FIG. 7 and the thickness of the light absorption film. From these results, it was found that the ultraviolet absorption filter according to Comparative Example 1 had a high transmittance of 40.78% at a wavelength of 400 nm, and had a problem with respect to absorption of light near a wavelength of 400 nm. This is due to the absorption characteristics of the dye Uvinul 3049, and it was confirmed that Uvinul 3049 alone cannot sufficiently absorb wavelengths around 400 nm.

<Comparative example 2>
The ultraviolet absorbent composition according to Comparative Example 2 was prepared in the same manner as in Comparative Example 1, except that Uvinul 3050 (manufactured by BASF) was used instead of the ultraviolet absorbent used in the preparation of the ultraviolet absorbent composition according to Comparative Example 1. A composition was prepared, and a light absorption film was formed to produce an ultraviolet absorption filter according to Comparative Example 2. The transmission spectrum of the ultraviolet absorption filter according to Comparative Example 2 at an incident angle of 0° was measured in the same manner as in Example 1. In addition, the thickness of the light absorption film in the ultraviolet absorption filter according to Comparative Example 2 was calculated in the same manner as in Example 1. FIG. 8 shows the transmission spectrum of the ultraviolet absorption filter according to Comparative Example 2 at an incident angle of 0°. Tables 2 to 4 show each parameter that can be seen from the transmission spectrum in FIG. 8 and the thickness of the light absorption film.

<Comparative example 3>
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, 1.646 g of Plysurf A208N (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), a phosphate ester compound, was added to the obtained copper acetate solution and stirred for 30 minutes to obtain liquid 13-A. 40 g of THF was added to 0.706 g of phenylphosphonic acid and stirred for 30 minutes to obtain liquid 13-B1. 40 g of THF was added to 4.230 g of 4-bromophenylphosphonic acid and stirred for 30 minutes to obtain liquid 13-B2. Mix 13-B1 liquid and 13-B2 liquid and stir for 1 minute to add 8.664 g of methyltriethoxysilane (MTES) (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KBE-13) and tetraethoxysilane (TEOS). (Special grade, manufactured by Kishida Chemical Co., Ltd.) 2.830 g was added to this mixed solution, and the mixture was further stirred for 1 minute to obtain Solution 13-B. While stirring the 13-A solution, the 13-B solution was added to the 13-A solution, and the mixture was stirred at room temperature for 1 minute. Next, 140 g of toluene was added to this solution, and the mixture was stirred at room temperature for 1 minute to obtain liquid 13-C. This 13-C solution was put into a flask and heated in an oil bath (manufactured by Tokyo Rikakikai Co., Ltd., model: OSB-2100), while the solvent was removed using a rotary evaporator (manufactured by Tokyo Rikakikai Co., Ltd., model: N-1110SF). processed. The set temperature of the oil bath was adjusted to 105°C. Thereafter, the liquid after the solvent removal treatment was taken out of the flask to obtain liquid 13-D. In this way, a 13-D liquid containing an aryl phosphonic acid, a copper component, a phosphoric acid ester, and an alkoxysilane or a hydrolyzate thereof was obtained.

4.500 g of copper acetate monohydrate and 240 g of THF were mixed and stirred for 3 hours to obtain a copper acetate solution. Next, 2.572 g of Plysurf A208N, which is a phosphate ester compound, was added to the obtained copper acetate solution and stirred for 30 minutes to obtain liquid 13-E. Further, 40 g of THF was added to 2.886 g of n-butylphosphonic acid and stirred for 30 minutes to obtain a 13-F solution. While stirring the 13-E solution, the 13-F solution was added to the 13-E solution, and the mixture was stirred at room temperature for 1 minute. Next, 100 g of toluene was added to this solution, and the mixture was stirred at room temperature for 1 minute to obtain liquid 13-G. This 13-G solution was placed in a flask and heated in an oil bath, while being subjected to solvent removal treatment using a rotary evaporator. The set temperature of the oil bath was adjusted to 105°C. Thereafter, the liquid after the solvent removal treatment was taken out of the flask to obtain a 13-H liquid. In this way, a 13-H solution containing an alkyl phosphonic acid, a copper component, and a phosphoric acid ester was obtained.

8.800 g of silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KR-300) was added to Liquid 13-D and stirred for 30 minutes to obtain Liquid 13-I. An amount corresponding to 40% by mass of the total amount of 13-H solution was added to 13-I solution and stirred for 30 minutes to obtain a light-absorbing composition according to Comparative Example 3. The light-absorbing composition according to Comparative Example 3 contains an aryl phosphonic acid, an alkyl phosphonic acid, a copper component, a phosphoric acid ester, an alkoxysilane or a hydrolyzate thereof, and a polymerizable resin. there was.

A dispenser was used in a 40 mm x 40 mm area at the center of one main surface of a transparent glass substrate made of borosilicate glass (manufactured by SCHOTT, product name: D263 T eco) having dimensions of 76 mm x 76 mm x 0.21 mm. Then, the light-absorbing composition according to Comparative Example 3 was applied to form a coating film. After sufficiently drying the obtained coating film at room temperature, it was placed in an oven and heat-treated at 45°C for 2 hours and at 85°C for 30 minutes to volatilize the solvent and harden the coating film. Further, the transparent glass substrate was placed in an environment of 85° C. and 85% relative humidity for about 2 hours to promote the hydrolysis reaction of the alkoxysilane. In this way, a light absorption film according to Comparative Example 3 was formed, and an optical filter according to Comparative Example 3 was obtained.

The transmission spectrum of the optical filter according to Comparative Example 3 at an incident angle of 0° was measured in the same manner as in Example 1. In addition, the thickness of the light absorption film in the optical filter according to Comparative Example 3 was calculated in the same manner as in Example 1. FIG. 9 shows the transmission spectrum of the optical filter according to Comparative Example 3 at an incident angle of 0°. Tables 2 to 4 show each parameter that can be seen from the transmission spectrum in FIG. 9 and the thickness of the light absorption film. From these results, it was confirmed that the transmittance at 400 nm of the optical filter according to Comparative Example 3 was 35.06%, and the ultraviolet absorption characteristics of the optical filter according to Comparative Example 3 were insufficient.

<Comparative example 4>
A dispenser was used in a 40 mm x 40 mm area at the center of one main surface of a transparent glass substrate made of borosilicate glass (manufactured by SCHOTT, product name: D263 T eco) having dimensions of 76 mm x 76 mm x 0.21 mm. Then, the ultraviolet absorbing composition according to Comparative Example 1 was applied to form a coating film. The resulting coating film was placed in an oven and heat-treated at 45° C. for 2 hours and at 85° C. for 1 hour to volatilize the solvent and cure the coating film, thereby forming a light-absorbing film. Next, the light-absorbing composition according to Comparative Example 3 was similarly applied to the other main surface of the transparent glass substrate to form a coating film. After sufficiently drying the obtained coating film at room temperature, it was placed in an oven and heat-treated at 45°C for 2 hours and at 85°C for 30 minutes to volatilize the solvent and harden the coating film. Thereafter, the transparent glass substrate was placed in an environment with a temperature of 85° C. and a relative humidity of 85% for about 2 hours to promote the hydrolysis reaction of the alkoxysilane. In this way, the light absorption film according to Comparative Example 4 was formed on both sides of the transparent glass substrate, and an optical filter according to Comparative Example 4 was obtained.

The transmission spectrum of the optical filter according to Comparative Example 4 at an incident angle of 0° was measured in the same manner as in Example 1. In addition, the thickness of the light absorption film in the optical filter according to Comparative Example 4 was calculated in the same manner as in Example 1. FIG. 10 shows the transmittance of the optical filter according to Comparative Example 4 at an incident angle of 0°. Tables 2 to 4 show each parameter that can be seen from the transmission spectrum and the thickness of the light absorption film. From these results, the transmittance of the optical filter according to Comparative Example 4 at a wavelength of 400 nm was as high as 14.52%, and it was difficult to say that the optical filter according to Comparative Example 4 had sufficient light absorption characteristics. . For this reason, it has been found that simply forming a layer containing an ultraviolet absorber and a layer containing copper phosphonate separately and stacking them on each other has a drawback regarding the absorption of light at a wavelength of around 400 nm. Therefore, it is suggested that combining a predetermined ultraviolet absorber and a metal component in the same layer as in Examples 1 to 4 is advantageous from the viewpoint of light absorption at a wavelength of around 400 nm.

The UV cutoff wavelengths λ ^UV _CF of the optical filters according to Examples 1 to 4 are 445 nm, 434 nm, 436 nm, and 430 nm, respectively. In addition, the transmittance T ₄₀₀ of the optical filters according to Examples 1 to 4 is 1.49%, 4.93%, 1.82%, and 4.54%, respectively. On the other hand, the ultraviolet absorption filters according to Comparative Examples 1 and 2 are filters that utilize the light absorption performance of a single benzophenone ultraviolet absorber, and the UV cutoff wavelength λ ^UV _CF of the ultraviolet absorption filters according to Comparative Examples 1 and 2 is , 402 nm and 398 nm, respectively. In addition, the transmittance T ₄₀₀ of the ultraviolet absorption filters according to Comparative Examples 1 and 2 is 40.78% and 57.15%, respectively. The optical filter according to Comparative Example 4 includes a light absorption film containing only a benzophenone ultraviolet absorber and a light absorption film containing phosphonic acid and a copper component on both sides of a transparent glass substrate. The UV cutoff wavelength λ ^UV _CF of the optical filter according to Comparative Example 4 is 412 nm, and the transmittance T ₄₀₀ of the ultraviolet absorption filter according to Comparative Examples 1 and 2 is 14.52%. Therefore, the UV cutoff wavelength λ ^UV _CF of the optical filter according to the example is about 30 nm larger than the UV cutoff wavelength λ ^UV _CF of the ultraviolet absorption filter according to Comparative Examples 1 and 2, and the optical filter according to Comparative Example 4 It is approximately 15 nm or more larger than the UV cutoff wavelength λ ^UV _CF of the filter. Further, the transmittance _T400 of the optical filter according to the example is about 35 points or more smaller than the T400 of the optical filter according to Comparative Examples 1 and 2, and about 10 points or more smaller than the transmittance _T400 of the optical filter according to Comparative Example 4. small. From these facts, it is understood that the light absorption properties of the optical filter according to the present invention in the short wavelength region including ultraviolet rays can be expressed at longer wavelengths than the light absorption properties exhibited by the benzophenone ultraviolet absorber alone. be done. The mechanism for such effects is unclear. For example, in the process of preparing a light-absorbing composition, the hydroxyl group of the ultraviolet absorber interacts with the copper component to form a complex, causing the inherent absorption properties of the ultraviolet absorber to shift toward longer wavelengths. This is considered to be the reason why such an effect was obtained.

According to Examples 1 to 4, in the light-absorbing composition, the ratio of the content of the ultraviolet absorber to the solid content of the resin is 0.36% to 1.09% on a mass basis, It has been found to be advantageous for obtaining good properties. On the other hand, according to Comparative Examples 1 and 2, in the ultraviolet absorbing composition, the ratio of the content of the ultraviolet absorber to the solid content of the resin was 2.00% on a mass basis, and A large amount of pigment is added. Nevertheless, the ultraviolet absorption characteristics of the ultraviolet absorption filters according to Comparative Examples 1 and 2 are significantly inferior to the ultraviolet absorption characteristics of the optical filters according to Examples 1 to 4. According to the present invention, in a light-absorbing composition, it is possible to achieve good ultraviolet absorption characteristics even if the ratio of the content of the ultraviolet absorber to the solid content of the resin is adjusted to less than 2.00%. It is understood that A small ratio of the content of the ultraviolet absorber to the solid content of the resin is advantageous from the viewpoint of suppressing the occurrence of problems such as deterioration in weather resistance or bleed-out. In the light-absorbing composition, the ratio of the content of the ultraviolet absorber to the solid content of the resin is preferably 0.1% to 1.8%, more preferably 0.2 to 1.8%, based on mass. It is 1.5%.

According to Examples 1 to 4, in the light-absorbing composition, the ratio of the ultraviolet absorber content to the phosphonic acid content is adjusted to 0.263% to 0.788% on a mass basis. . From this result, it is understood that the optical filter can exhibit advantageous properties by using a much smaller amount of ultraviolet absorber than phosphonic acid. Since the ratio of the content of the ultraviolet absorber to the content of phosphonic acid is not too large, it is possible to suppress a decrease in visible light transmittance. The ratio of the content of the ultraviolet absorber to the content of phosphonic acid is preferably 0.1 to 5.0%, more preferably 0.1 to 3.0%, and even more preferably It is 0.1 to 1.0%.

According to Examples 1 to 4, in the light-absorbing composition, the ratio of the content of the ultraviolet absorber to the content of the copper component is 0.002 to 0.006 based on the amount of substance. It is assumed that many of the copper components form a complex with phosphonic acid. Therefore, the content of the copper component is larger than the content of the ultraviolet absorber. The ratio of the content of the ultraviolet absorber to the content of the copper component is preferably 0.001 to 0.100, more preferably 0.001 to 0.030, based on the amount of substance.

The optical filter of the present invention, like the optical filters according to Examples 1 to 4, is produced by coating a light-absorbing composition on a transparent glass substrate and curing the coating film to form an absorbing film. It can be a laminate of a transparent substrate and a light absorption film. On the other hand, the optical filter of the present invention may be an optical filter consisting only of a light-absorbing film, which is obtained by forming a light-absorbing film on a support and then peeling the light-absorbing film from the support. According to FIG. 11, it is understood that the transmission spectrum of the transparent glass substrate does not significantly affect the optical properties shown in Tables 2 to 4. This is because, in the transmission spectrum of a transparent glass substrate, the transmittance is approximately constant from at least a specific wavelength exceeding 350 nm to a wavelength of 1200 nm. Therefore, even if the optical filter includes a light absorption film and does not have a transparent glass substrate, the conditions of 8≦T ₅₅₀ /T ₄₀₀ and 8≦T ₅₅₀ /T ₈₀₀ , the conditions (I) to (X), and Conditions (α) to (γ) can be satisfied.

(Detection of ultraviolet absorber)
An ethanol elution test was conducted on the ultraviolet absorber contained in the light absorption film in the following manner.

<Example 5>
First, in order to easily remove the light absorption film from the optical filter, the main surface of a transparent glass substrate on which the light absorption film is to be formed was previously surface-treated with a fluorine compound to prepare a fluorine-treated substrate. 0.1 g of surface antifouling coating agent (manufactured by Daikin Industries, Ltd., product name: Optool DSX, active ingredient concentration: 20% by mass) and 19.9 g of hydrofluoroether-containing liquid (manufactured by 3M Company, product name: Novec 7100) and stirred for 5 minutes to prepare a fluorination agent (concentration of active ingredient: 0.1% by mass). This fluorine treatment agent was applied to the main surface of a transparent glass substrate made of borosilicate glass (manufactured by SCHOTT, product name: D263 T eco) measuring 76 mm x 76 mm x 0.21 mm to form a coating film, and then heated at room temperature for 24 hours. The coating film of the fluorine treatment agent was left to dry for a while. Thereafter, the glass surface was lightly wiped with a dust-free cloth containing Novec 7100 to remove excess fluorine treatment agent, etc., to obtain a fluorine treatment substrate.

The entire amount of the light-absorbing composition obtained under the same conditions and method as in Example 3 was applied to one main surface of the fluorine-treated substrate using a dispenser to form a coating film, and the resulting coating film was After sufficiently drying at room temperature, it was placed in an oven and heat-treated at 45°C for 2 hours and at 85°C for 30 minutes. Thereby, the solvent contained in the light-absorbing composition was volatilized and the coating film was cured. Further, the fluorine-treated substrate was placed in an environment at a temperature of 85° C. and a relative humidity of 85% for about 2 hours to promote the hydrolysis reaction of the alkoxysilane. In this way, the light absorption film according to Example 5 was formed, and the optical filter according to Example 5 was obtained. The ultraviolet absorber contained in the light absorption film was 2,2'-4,4'-tetrahydroxybenzophenone.

Next, the light absorption film was carefully peeled off from the optical filter according to Example 5 using tweezers to obtain a film-like light absorption film. The mass of the light absorption film was 9.500 g. In the process of producing the light-absorbing composition according to Example 3, the 3-U solution contained 5% by mass of an ultraviolet absorber, and 0.960 g of the 3-U solution was added to prepare the light-absorbing composition. Therefore, the light absorbing film contained 0.048 g of ultraviolet absorber. The content of the ultraviolet absorber in the light absorption film was 0.505% on a mass basis.

A part of the light-absorbing film was cut to take out 0.100 g of light-absorbing film fragments, and the pieces were immersed in 1.000 g of ethanol for 24 hours in an attempt to elute the ultraviolet absorber contained in the light-absorbing film fragments. . The amount of ultraviolet absorber contained in a 0.100 g light-absorbing film fragment was 0.000505 g. Assuming that all of the ultraviolet absorber contained in this fragment is eluted into ethanol, the ultraviolet absorber in ethanol can be calculated to be 0.050% on a mass basis. On the other hand, as a control, fragments of a light-absorbing film were prepared in the same manner using the light-absorbing composition according to Comparative Example 3, which did not contain an ultraviolet absorber, and immersed in 1.000 g of ethanol for 24 hours to prevent elution. I observed the situation.

The ethanol containing fragments of the light-absorbing film containing the ultraviolet absorber was colored yellow, indicating that components that absorb in the visible light region were eluted from the light-absorbing film into the ethanol. It was suggested. The ethanol containing fragments of the light-absorbing film without the UV absorber remained nearly colorless and transparent. In ethanol containing a fragment of a light-absorbing film containing an ultraviolet absorber, LC-UV measurements were performed to identify components that absorb in a region including the visible light region. For this measurement, a high performance liquid chromatography device Ultimate 3000 manufactured by Thermo Fisher Scientific was used. FIG. 12 shows the spectrum of the LC-UV chromatography in this measurement at a wavelength of 450±150 nm. In FIG. 12, the horizontal axis represents time [minutes], and the vertical axis represents relative absorption intensity. As a control, the background (relative The absorption intensity remained at almost zero), and no characteristic movements were observed.

In FIG. 12, a characteristic absorption intensity peak was seen at a time of 5.8 minutes. The absorption spectrum of this peak is shown in FIG. The horizontal axis represents wavelength [nm], and the vertical axis represents relative absorbance. From the spectrum shown in FIG. 13, it was confirmed that there were characteristic absorption peaks at wavelengths of 285 nm and 342 nm.

Next, LC-MS measurements were performed on ethanol containing fragments of the light-absorbing film containing the ultraviolet absorber. The measurement was performed using a liquid chromatography mass spectrometer, Orbitrap Fusion, manufactured by Thermo Fisher Scientific. According to the mass spectrum that is the measurement result, it was found that the eluate into ethanol contained C ₁₃ H ₉ O ₅ (negative ion detection) and C ₁₃ H ₁₁ O ₅ (positive ion detection).

From the results of these LC-UV measurements and LC-MS measurements, it was estimated that the components eluted into ethanol from the light-absorbing film containing the ultraviolet absorber contained tetrahydroxybenzophenone, which is an ultraviolet absorber.

(Identification of eluted components of ultraviolet absorber)
The transmission spectrum of the ethanol solution in which the ultraviolet absorber was eluted from the fragment of the light-absorbing film according to Example 5 was measured. The ethanol solution containing the UV absorber was filled into a quartz cell (manufactured by JASCO Corporation, model number J/1/Q/1) with an optical path length of 1 mm, and a UV-visible near-infrared spectrophotometer (manufactured by JASCO Corporation) was charged. , product name: V-670) to measure its transmission spectrum. The transmission spectrum is shown in FIG. At a wavelength of 300 to 450 nm, the value obtained by dividing the minimum value of transmittance by the maximum value of transmittance was 0.895. The minimum value of transmittance corresponded to the minimum value of transmittance near a wavelength of 348 nm.

Next, 2,2',4,4'-tetrahydroxybenzophenone, which is an ultraviolet absorber, is dissolved in ethanol, and 0.005%, 0.010%, 0.025%, 0.100% on a mass basis, and 5 types of ethanol solutions in which 0.200% ultraviolet absorber was dissolved were prepared. The transmission spectra of the ethanol solutions in which these ultraviolet absorbers were dissolved were measured in the same manner as the ethanol solutions in which the ultraviolet absorbers were eluted from the fragments of the light-absorbing film containing the ultraviolet absorbers according to Example 5. This transmission spectrum is shown in FIG. In these transmission spectra, the wavelength corresponding to the minimum value of transmittance was 348 nm. Furthermore, in these transmission spectra, the value tr, which is the minimum value of transmittance divided by the maximum value of transmittance, was determined. Table 5 and FIG. 16 show the relationship between the concentration η [%] of the ultraviolet absorbent and the value tr. From the graph shown in FIG. 16, the relationship between the concentration η [%] and the value tr is η=(-1/a)ln(tr/b) (where a=1.213×10 ¹ , b=1. 004). The broken line graph shown in FIG. 16 is a calibration curve for determining the concentration of the ultraviolet absorbent. In the ethanol solution in which the ultraviolet absorber in the light-absorbing film according to Example 5 was eluted, tr=0.895. Therefore, when the light-absorbing film according to Example 5 is immersed in ethanol and the UV absorber is eluted into the ethanol, the UV absorber is dissolved so that the concentration of the UV absorber is 0.0095% on a mass basis. It was suggested that the ethanol solution had the same light transmission properties as the ethanol solution.

When the UV absorber is eluted into ethanol from the fragment of the light absorbing film containing the UV absorber according to Example 5, it is assumed that 0.0095% of the UV absorber is contained in the ethanol on a mass basis. It is understood from the above study that when all the ultraviolet absorber contained in the light absorption film is eluted, the concentration of the ultraviolet absorber in the ethanol solution is 0.05%. Therefore, it is estimated that 19% of the ultraviolet absorber contained in the light absorption film was eluted into ethanol from the fragments of the light absorption film containing the ultraviolet absorber according to Example 5 based on the mass.

<Comparative example 5>
A light-absorbing composition according to Comparative Example 5 was obtained under the same conditions and method as in Example 5, except that all the additions of phosphonic acid and copper acetate monohydrate were omitted. In addition, a fluorine-treated substrate was produced in the same manner as in Example 5. The entire amount of the light-absorbing composition according to Comparative Example 5 was applied to one main surface of the fluorine-treated substrate using a dispenser, and the resulting coating film was sufficiently dried at room temperature, and then placed in an oven for 45 minutes. A heat treatment was performed at 85° C. for 2 hours and 30 minutes at 85° C. to volatilize the solvent and harden the coating film. Further, the transparent glass substrate was placed in an environment of 85° C. and 85% relative humidity for about 2 hours to promote the hydrolysis reaction of the alkoxysilane. In this way, a light absorption film according to Comparative Example 5 was formed, and an optical filter according to Comparative Example 5 was obtained.

Next, the light absorption film was carefully peeled off from the optical filter according to Comparative Example 5 using tweezers to obtain a film-like light absorption film. The total amount of the obtained light-absorbing film was 4.200 g. In the process of producing a light-absorbing composition according to Comparative Example 5, a liquid containing an ultraviolet absorber corresponding to the 3-U liquid contained 5% by mass of an ultraviolet absorber, and 0.960 g of the liquid was added. A light-absorbing composition was prepared. Therefore, the light-absorbing film contained 0.048 g of ultraviolet absorber, and the content of the ultraviolet absorber in the light-absorbing film was 1.130% on a mass basis.

Cut a part of the light-absorbing film, take out 0.100 g of light-absorbing film fragments, and soak them in 1.000 g of ethanol for 24 hours to try to elute the ultraviolet absorber contained in the light-absorbing film fragments. Ta. The amount of ultraviolet absorber contained in 0.100 g of the light absorption film was 0.00113 g. Assuming that all of the ultraviolet absorber is eluted into ethanol, the concentration of the ultraviolet absorber in the ethanol solution can be calculated to be 0.113% on a mass basis.

(Identification of eluted components of ultraviolet absorber)
The transmission spectrum of the ethanol solution in which the ultraviolet absorber was eluted from the fragment of the light-absorbing film according to Comparative Example 5 was measured. The ethanol solution containing the UV absorber was filled into a quartz cell (manufactured by JASCO Corporation, model number J/1/Q/1) with an optical path length of 1 mm, and a UV-visible near-infrared spectrophotometer (manufactured by JASCO Corporation) was charged. , product name: V-670) to measure its transmission spectrum. The transmission spectrum is shown in FIG. At a wavelength of 300 to 450 nm, the value tr, which is the minimum value of transmittance divided by the maximum value of transmittance, was 0.550. According to the calibration curve shown in FIG. 16 and the above equation representing the calibration curve, when the light-absorbing film according to Comparative Example 5 is immersed in ethanol and the ultraviolet absorber is eluted into the ethanol, the concentration of the ultraviolet absorber is It was found that it had light transmission characteristics equivalent to an ethanol solution in which an ultraviolet absorber was dissolved at a concentration of 0.0496% on a mass basis.

When the UV absorber was eluted into ethanol from the fragment of the light absorbing film containing the UV absorber according to Comparative Example 5, it was assumed that the ethanol solution contained 0.0496% of the UV absorber on a mass basis. It is understood from the above study that if all the ultraviolet absorber contained in the light-absorbing film is eluted into ethanol, the concentration of the ultraviolet absorber in the ethanol solution will be 0.113%. Therefore, it was estimated that 43.89% of the ultraviolet absorber contained in the light-absorbing film was eluted into ethanol.

Comparing Example 5 and Comparative Example 5, it is understood that in Comparative Example 5, more ultraviolet absorber was eluted into ethanol. In a light-absorbing film containing a UV absorber, the UV absorber is included with metal components such as copper, which causes some interactions such as complexation, and the UV absorber is eluted into organic solvents such as ethanol. It is estimated that it will become difficult.

When a light absorption film containing an ultraviolet absorber and a metal component such as copper is immersed in ethanol for 24 hours, the amount of ultraviolet absorber eluted into the ethanol is the amount contained in the light absorption film on a mass basis. It was suggested that the UV absorber should be adjusted to 10% to 40%, more quantitatively 10% to 20%.

1a, 1b optical filter 10 light absorption film 20 transparent dielectric substrate

Claims (18)

A light-absorbing composition,
phosphonic acid,
an ultraviolet absorber having a hydroxyl group and a carbonyl group in its molecule;
Contains a metal component,
In the transmission spectrum at an incident angle of 0 degrees of the light-absorbing film obtained by curing the light-absorbing composition, transmittance T 400 at a wavelength of 400 nm, transmittance T 550 at a wavelength of 550 nm, and transmittance at a wavelength _of 800 _nm . T ₈₀₀ satisfies the conditions of 8≦T ₅₅₀ /T ₄₀₀ and 8≦T ₅₅₀ /T ₈₀₀ ,
Light-absorbing composition. The light-absorbing composition according to claim 1, wherein the hydroxy group and the carbonyl group are separated by 1 to 6 atoms. The light-absorbing composition according to claim 1 or 2 , wherein the ultraviolet absorber contains a benzophenone compound represented by the following formula (A1).

[In formula (A1), at least one of R ₁₁ , R ₁₂ , R ₂₁ , and R ₂₂ is a hydroxy group. In formula (A1), when R ₁₁ , R ₁₂ , R ₂₁ , or R ₂₂ is a functional group other than a hydroxy group, plural R ₁₁ , plural R ₁₂ , plural R ₂₁ , or plural R ₂₂ are At least one of R ₁₁ , R ₁₂ , R ₂₁ , and R ₂₂ may be absent. ] The light-absorbing composition according to any one of claims 1 to 3 , wherein the ultraviolet absorber contains a benzophenone compound represented by the following formula (A2).

[In formula (A2), R ₃₁ is a hydroxy group, a carboxyl group, an aldehyde group, a halogen, an alkyl group having 1 to 12 carbon atoms, or 1 to 12 in which one or more hydrogen atoms are substituted with a halogen atom. an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms in which one or more hydrogen atoms have been replaced with a halogen atom; Optionally, R ₃₁ may be absent. In formula (A2), R ₄₁ and R ₄₂ are a hydroxy group, a carboxyl group, an aldehyde group, a halogen, an alkyl group having 1 to 12 carbon atoms, or a group in which one or more hydrogen atoms are substituted with a halogen atom. - an alkyl group having 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms in which one or more hydrogen atoms have been replaced with a halogen atom; R ₄₁ and R ₄₂ may be absent. In formula (A2), a plurality of R ₄₁ may be present, and a plurality of R ₄₂ may be present. ] The light-absorbing composition according to claim 1 , wherein the phosphonic acid is represented by the following formula (B).

[In formula (B), R ₃ is an alkyl group, a halogenated alkyl group in which at least one hydrogen atom in the alkyl group is replaced with a halogen atom, an aryl group, or an aryl group in which at least one hydrogen atom is replaced by a halogen atom] It is a substituted halogenated aryl group. ] The light-absorbing composition according to any one of claims 1 to 5 , wherein the metal component includes a copper component. The light-absorbing composition according to any one of claims 1 to 6 , further containing a phosphoric acid ester. phosphonic acid,
an ultraviolet absorber having a hydroxyl group and a carbonyl group in its molecule;
Contains a metal component,
In the transmission spectrum at an incident angle of 0 degrees, the transmittance T ₄₀₀ at a wavelength of 400 nm , the transmittance T ₅₅₀ at a wavelength of 550 nm , and the transmittance T ₈₀₀ at a wavelength of 800 nm are 8≦T ₅₅₀ /T ₄₀₀ and 8≦T ₅₅₀ / Meets the conditions of T ₈₀₀ ,
light absorption film. The light-absorbing film according to claim 8 , wherein the hydroxy group and the carbonyl group are separated by 1 to 6 atoms. The light absorption film according to claim 8 or 9 , wherein the ultraviolet absorber contains a benzophenone compound represented by the following formula (A1).

[In formula (A1), at least one of R ₁₁ , R ₁₂ , R ₂₁ , and R ₂₂ is a hydroxy group. In formula (A1), when R ₁₁ , R ₁₂ , R ₂₁ , or R ₂₂ is a functional group other than a hydroxy group, plural R ₁₁ , plural R ₁₂ , plural R ₂₁ , or plural R ₂₂ are At least one of R ₁₁ , R ₁₂ , R ₂₁ , and R ₂₂ may be absent. ] The light-absorbing film according to any one of claims 8 to 10 , wherein the ultraviolet absorber contains a benzophenone compound represented by the following formula (A2).

[In formula (A2), R ₃₁ is a hydroxy group, a carboxyl group, an aldehyde group, a halogen, an alkyl group having 1 to 12 carbon atoms, or 1 to 12 in which one or more hydrogen atoms are substituted with a halogen atom. an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms in which one or more hydrogen atoms have been replaced with a halogen atom; Optionally, R ₃₁ may be absent. In formula (A2), R ₄₁ and R ₄₂ are a hydroxy group, a carboxyl group, an aldehyde group, a halogen, an alkyl group having 1 to 12 carbon atoms, or a group in which one or more hydrogen atoms are substituted with a halogen atom. - an alkyl group having 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms in which one or more hydrogen atoms have been replaced with a halogen atom; R ₄₁ and R ₄₂ may be absent. In formula (A2), a plurality of R ₄₁ may be present, and a plurality of R ₄₂ may be present. ] The light-absorbing film according to any one of claims 8 to 11 , wherein the phosphonic acid is represented by the following formula (B).

[In formula (B), R ₃ is an alkyl group, a halogenated alkyl group in which at least one hydrogen atom in the alkyl group is replaced with a halogen atom, an aryl group, or an aryl group in which at least one hydrogen atom is replaced by a halogen atom] It is a substituted halogenated aryl group. ] The light absorption film according to any one of claims 8 to 12 , wherein the metal component includes a copper component. The light-absorbing film according to any one of claims 8 to 13 , further containing a phosphoric acid ester. An optical filter comprising the light absorption film according to any one of claims 8 to 14 . In the transmission spectrum at an incident angle of 0 degrees, the transmittance T ₄₀₀ at a wavelength of 400 nm, the transmittance T ₅₅₀ at a wavelength of 550 nm, and the transmittance T ₈₀₀ at a wavelength of 800 nm are 8≦T ₅₅₀ /T ₄₀₀ and 8≦T ₅₅₀ / The optical filter according to claim 15 , which satisfies the condition of T ₈₀₀ . In the transmission spectrum, the following conditions (I), (II), (III), (IV), (V), (VI), (VII), (VIII), (IX), and (X) are further set. 17. The optical filter according to claim 16, which satisfies the requirements of claim 16 .
(I) The maximum transmittance in the wavelength range of 300 nm to 380 nm is 1% or less.
(II) Transmittance at a wavelength of 400 nm is 20% or less.
(III) The UV cutoff wavelength λ ^UV _CF , which is the wavelength at which the transmittance is 50% in the wavelength range of 400 nm to 490 nm, satisfies the condition of 405 nm≦λ ^UV _CF ≦480 nm.
(IV) The average value of transmittance in the wavelength range of 480 nm to 580 nm is 78% or more.
(V) The IR cutoff wavelength λ ^IR _CF , which is the wavelength at which the transmittance is 50% in the wavelength range of 590 nm to 700 nm, satisfies the condition of 600 nm≦λ ^IR _CF ≦700 nm.
(VI) The average value of transmittance at a wavelength of 700 nm to 750 nm is 10% or less.
(VII) The maximum transmittance in the wavelength range of 800 nm to 950 nm is 3% or less.
(VIII) The maximum transmittance in the wavelength range of 700 nm to 1000 nm is 10% or less.
(IX) The maximum transmittance in the wavelength range of 700 nm to 1100 nm is 15% or less.
(X) The maximum transmittance in the wavelength range of 700 nm to 1200 nm is 20% or less. The optical filter according to claim 17 , wherein the transmission spectrum further satisfies the following conditions (α), (β), and (γ).
(α) In the wavelength range of 300 nm to 450 nm, the difference between the maximum wavelength showing 1% transmittance and the minimum wavelength showing 1% transmittance is 90 nm or more.
(β) The difference between the IR cutoff wavelength λ ^IR _CF and the UV cutoff wavelength λ ^UV _CF is 180 nm or more.
(γ) In the wavelength range of 700 nm to 1200 nm, the difference between the maximum wavelength showing 1% transmittance and the minimum wavelength showing 1% transmittance is 200 nm or more.

Images