Light-absorptive composition, light-absorbing film, light-absorbing film manufacturing method, and optical filter

Abstract

A light-absorptive composition according to the present invention contains: an ultraviolet absorbing agent having a hydroxy group and a carbonyl group in the molecule; and metal components. At least a portion of the metal components is bound to an organic oxy group.

Description

Light-absorbing composition, light-absorbing film, method for producing light-absorbing film, and optical filter

[0001] The present invention relates to a light-absorbing composition, a light-absorbing film, a method for producing a light-absorbing film, and an optical filter.

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

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

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

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

[0006] Furthermore, Patent Document 3 describes an ophthalmic device including a vertical violet light cutoff filter, which sharply absorbs light with wavelengths in the range of approximately 400 nm to 450 nm.

[0007] International Publication No. 2018 / 088561 Patent No. 6232161 Special Publication No. 2007-535708

[0008] The techniques described in Patent Documents 1 and 2 need to be reconsidered from the perspective of light absorption characteristics in the short wavelength region around 400 nm. On the other hand, the violet light vertical cutoff filter described in Patent Document 3 is thought to have low transmittance for visible light in the wavelength region around 500 to 650 nm. Therefore, the present invention provides a light-absorbing composition, a light-absorbing film, and an optical filter that are advantageous from the perspective of reproducing human visual sensitivity, particularly light absorption characteristics in the short wavelength region. The present invention also provides a method for producing such a light-absorbing film.

[0009] The present invention provides a light-absorbing composition comprising: an ultraviolet absorber having a hydroxy group and a carbonyl group in the molecule; and a metal component, wherein at least a portion of the metal component is bonded to an organic oxy group.

[0010] The present invention also provides a light-absorbing film comprising: an ultraviolet absorber having a hydroxy group and a carbonyl group in the molecule; and a metal component, wherein at least a portion of the metal component is bonded to an organic oxy group.

[0011] The present invention also provides a method for producing a light-absorbing film, which comprises curing the light-absorbing composition by heating at a temperature of 120° C. or higher.

[0012] The present invention also provides an optical filter comprising the above-mentioned light-absorbing film.

[0013] The light-absorbing composition is advantageous from the viewpoint of reproducing human visual sensitivity, particularly from the viewpoint of light absorption characteristics in the short wavelength region. In addition, the light-absorbing film and the optical filter are advantageous from the viewpoint of reproducing human visual sensitivity, particularly from the viewpoint of light absorption characteristics in the short wavelength region.

[0014] FIG. 1 is a cross-sectional view showing an example of a light-absorbing film according to the present invention. FIG. 2A is a cross-sectional view showing an example of an optical filter according to the present invention. FIG. 2B is a cross-sectional view showing an example of an optical filter according to the present invention. FIG. 3 is a transmission spectrum of an optical filter according to Example 1. FIG. 4 is a transmission spectrum of an optical filter according to Example 2. FIG. 5 is a transmission spectrum of an optical filter according to Example 3. FIG. 6 is a transmission spectrum of an optical filter according to Example 4. FIG. 7 is a transmission spectrum of an optical filter according to Example 5. FIG. 8 is a transmission spectrum of an optical filter according to Example 6. FIG. 9 is a transmission spectrum of an optical filter according to Example 7. FIG. 10 is a transmission spectrum of an optical filter according to Example 8. FIG. 11 is a transmission spectrum of an optical filter according to Example 9. FIG. 12 is a transmission spectrum of an optical filter according to Example 10. FIG. 13 is a transmission spectrum of an optical filter according to Example 11. FIG. 14 is a transmission spectrum of an optical filter according to Example 12. FIG. 15 is a transmission spectrum of an optical filter according to Example 13. FIG. 16 is a transmission spectrum of an optical filter according to Example 14. FIG. 17 is the transmission spectrum of the optical filter according to Example 15. FIG. 18 is the transmission spectrum of the optical filter according to Example 16. FIG. 19 is the transmission spectrum of the optical filter according to Example 17. FIG. 20 is the transmission spectrum of the optical filter according to Example 18. FIG. 21 is the transmission spectrum of the optical filter according to Example 19. FIG. 22 is the transmission spectrum of the optical filter according to Example 20. FIG. 23 is the transmission spectrum of the optical filter according to Comparative Example 1. FIG. 24 is the transmission spectrum of the optical filter according to Comparative Example 2. FIG. 25 is the transmission spectrum of the optical filter according to Comparative Example 3. FIG. 26 is the transmission spectrum of the optical filter according to Comparative Example 4. FIG. 27 is the transmission spectrum of the optical filter according to Comparative Example 5. FIG. 28 is the transmission spectrum of a transparent glass substrate. FIG. 29 is the transmission spectrum of the optical filter according to Example 21. FIG. 30 is the reflection spectrum of the optical filter according to Example 21. FIG. 31 is the transmission spectrum of the optical filter according to Example 21 in a high-temperature, high-humidity test.FIG. 32 is a transmission spectrum of the optical filter according to Example 21 in a heat cycle test. FIG. 33 is a transmission spectrum of the optical filter according to Example 23. FIG. 34 is a transmission spectrum of the optical filter according to Example 24. FIG. 35 is a transmission spectrum of the optical filter according to Example 26. FIG. 36 is a transmission spectrum of the optical filter according to Example 32. FIG. 37 is a reflection spectrum of the optical filter according to Example 23. FIG. 38 is a reflection spectrum of the optical filter according to Example 24. FIG. 39 is a reflection spectrum of the optical filter according to Example 26. FIG. 40 is a reflection spectrum of the optical filter according to Example 32. FIG. 41 is a transmission spectrum of the optical filter according to Example 36. FIG. 42 is a reflection spectrum of the optical filter according to Example 36. FIG. 43 is a reflection spectrum of the optical filter according to Example 38. FIG. 44 is a transmission spectrum of the optical filter according to Example 41. FIG. 45 is a reflection spectrum of the optical filter according to Comparative Example 6.

[0015] If an optical filter for an imaging device using a solid-state imaging element could effectively absorb light in the short-wavelength region around 400 nm, the value of the optical filter could be further enhanced from the perspective of reproducing human visual sensitivity. 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. 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. Based on these facts, it is difficult to say that the optical filters described in Patent Documents 1 and 2 are advantageous in terms of effectively absorbing light in the short-wavelength region around 400 nm. The violet light vertical cutoff filter described in Patent Document 3 may be able to effectively absorb light in the short-wavelength region around 400 nm, but the transmittance of the filter for visible light in the wavelength range of 500 to 650 nm is considered low.

[0016] Therefore, the present inventors have conducted extensive research to develop a light-absorbing composition that is advantageous from the viewpoint of reproducing human visual sensitivity, particularly from the viewpoint of effectively absorbing light in the short wavelength region around 400 nm in wavelength. As a result of extensive trial and error, the present inventors have newly discovered that a light-absorbing composition containing a predetermined ultraviolet absorber and a metal component is advantageous from the viewpoint of effectively absorbing light in the short wavelength region, and have completed the present invention.

[0017] Hereinafter, embodiments of the present invention will be described. Note that the following description is for illustrative purposes only and the present invention is not limited to the following embodiments.

[0018] The light-absorbing composition according to the present invention contains an ultraviolet absorber having a hydroxyl group and a carbonyl group in the molecule, and a metal component. Additionally, at least a portion of the metal component is bonded to an organic oxy group. Typically, at least a portion of the metal component is bonded to an oxygen atom in the organic oxy group. This allows a light-absorbing film or optical filter produced using the light-absorbing composition to effectively absorb light in a wavelength region around 400 nm, which is advantageous from the perspective of reproducing human visual sensitivity.

[0019] Advantageous conditions for an ultraviolet absorber include an appropriate light absorption range and transmittance range, photochemical stability, low enough photosensitization within the range of use to have no adverse effects, and thermochemical stability. From this perspective, it is considered that the light absorption mechanism of ultraviolet absorbers utilizes a hydrogen transfer reaction of a hydroxy group within the molecule due to photoexcitation (an intramolecular hydrogen abstraction reaction). Examples of ultraviolet absorbers that exhibit this mechanism include compounds such as hydroxybenzophenone, salicylic acid, hydroxyphenylbenzotriazole, hydroxyphenyltriazine, and substituted acrylonitrile. In hydroxybenzophenone and salicylic acid, a reaction involving hydrogen transfer between a hydroxy group and a carbonyl group contained within the molecule is involved in the absorption of ultraviolet light, etc. On the other hand, in hydroxyphenylbenzotriazole, hydroxyphenyltriazine, and substituted acrylonitrile, a reaction involving hydrogen transfer between a hydroxy group and a nitrogen atom contained within the molecule is involved in the absorption of ultraviolet light, etc. These UV absorbers contain a hydroxy group with an unshared electron pair in their molecule, which is presumed to cause interactions such as partial complexation with a coexisting metal component or hydrogen donor. In systems such as light-absorbing compositions containing UV absorbers and their cured products, a comparison was made between a case in which a UV absorber having a hydroxy group is present alone and a case in which a metal component or hydrogen donor and a UV absorber having a hydroxy group are present together. This comparison supports the above presumption, revealing differences in their optical properties, such as their light absorption spectra and light transmission spectra. In particular, it was found that a light-absorbing film obtained by curing a light-absorbing composition containing a UV absorber having a hydroxy group and a carbonyl group in its molecule and a metal component exhibits a shift in the light absorption band at wavelengths of 300 to 500 nm toward longer wavelengths. Therefore, such a light-absorbing film is advantageous for effectively and appropriately absorbing light with a wavelength of around 400 nm. In addition, when the light absorption band shifts to the longer wavelength side, for example, a phenomenon may become apparent in which the maximum absorption wavelength shifts to the longer wavelength side within the wavelength range of 300 nm to 500 nm in the transmission spectrum, or a phenomenon in which the wavelength at which the transmittance is 50% (UV cutoff wavelength) shifts to the longer wavelength side.Thus, in the light-absorbing composition according to the present invention, the light-absorbing film that is a cured product thereof, and the optical filter including the light-absorbing film, the absorption characteristics inherent to the ultraviolet absorber are adjusted so that light in the short wavelength region can be effectively absorbed, and as a result, the spectral transmittance of such a light-absorbing film or optical filter tends to be more appropriate when used together with a solid-state imaging device or the like.

[0020] As described above, in the light-absorbing composition, at least a portion of the metal component is bonded to an organic oxy group and typically exists in the form of M-O-R, where R represents a specific organic group, such as an alkyl group, an aryl group, or a vinyl group.

[0021] The arrangement of the hydroxy group and the 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 desirably arranged with one to three atoms between them. This is thought to facilitate hydrogen transfer between the hydroxy group and the carbonyl group in the ultraviolet absorber. Therefore, the phenomenon of the light absorption band in the wavelength range of 300 to 500 nm shifting to the longer wavelength side is likely to occur effectively. As a result, the light-absorbing film obtained by curing the light-absorbing composition is more likely to effectively and appropriately absorb light with a wavelength of around 400 nm.

[0022] In the transmission spectrum of the light-absorbing film obtained by curing the light-absorbing composition according to the present invention at an incident angle of 0 degrees, the transmittance T 400 is, for example, 10% or less. This makes it possible for the light-absorbing film obtained by curing the light-absorbing composition to more reliably absorb light with a wavelength of around 400 nm effectively and appropriately.

[0023] Transmittance T 400 is preferably 3% or less, and more preferably 1% or less.

[0024] The ultraviolet absorber is not limited to a specific ultraviolet absorber as long as it has a hydroxy group and a carbonyl group in its molecule. The ultraviolet absorber is preferably a compound that does not easily aggregate even when mixed with the metal component.

[0025] The ultraviolet absorber preferably contains a benzophenone-based compound represented by the following formula (A1): In this case, a light-absorbing film or optical filter produced using the light-absorbing composition is more likely to effectively absorb light in the short wavelength region around 400 nm.

[0026]

[0027] In formula (A1), R 11 , R 12 , R 21 , and R 22 At least one of R is a hydroxy group. 11 , R 12 , R 21 , or R 22 is a functional group other than a hydroxy group, a plurality of R 11 , multiple R 12 , multiple R 21 , or multiple R 22 may be present, and R 11 , R 12 , R 21 , and R 22 At least one of them may not be present.

[0028] 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 atom, 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 are substituted with halogen 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 are substituted with halogen atoms.

[0029] More preferably, the ultraviolet absorber contains a benzophenone-based compound represented by the following formula (A2): In this case, a light-absorbing film or optical filter produced using the light-absorbing composition is more likely to effectively absorb light in the short wavelength region around 400 nm.

[0030]

[0031] In formula (A2), R 31 is a hydrogen atom, a hydroxy group, a carboxyl group, an aldehyde group, a halogen atom, a group having a halogen atom, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. 41 and R 42 may be a hydroxy group, a carboxyl group, an aldehyde group, a group having a halogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms; R 41 and R 42 In formula (A2), a plurality of R 41 may be present, and multiple R 42 may be present. The group having a halogen atom may be a halogenated alkyl group in which at least one hydrogen atom in the alkyl group is substituted with a halogen atom. The group having a halogen atom may be a halogenated aryl group in which at least one hydrogen atom in the aryl group is substituted with a halogen atom. The group having a halogen atom may be a halogenated alkoxy group in which at least one hydrogen atom in the alkoxy group is substituted with a halogen atom.

[0032] The benzophenone compound represented by formula (A1) or formula (A2) is not limited to a specific compound, and examples of the benzophenone compound include at least one selected from the group consisting of 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'-carboxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-n-octoxybenzophenone, 2-hydroxy-5-chlorobenzophenone, and 2,4-dibenzoylresorcinol.

[0033] The ultraviolet absorber may contain a salicylic acid-based compound represented by the following formula (B): In this case, a light-absorbing film or optical filter produced using the light-absorbing composition is more likely to effectively absorb light in the short wavelength region around 400 nm.

[0034]

[0035] In formula (B), R 51 may be a hydroxy group, a carboxy group, a group containing a halogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. 51 may be present, and R 51 In formula (B), R may not be present. 52 is a hydrogen atom, an aryl group, or a halogenated aryl group in which one or more hydrogen atoms have been substituted with a halogen atom. The halogen-containing group may be a halogenated alkyl group in which at least one hydrogen atom in the alkyl group has been substituted with a halogen atom. The halogen-containing group may be a halogenated aryl group in which at least one hydrogen atom in the aryl group has been substituted with a halogen atom. The halogen-containing group may be a halogenated alkoxy group in which at least one hydrogen atom in the alkoxy group has been substituted with a halogen atom.

[0036] The salicylic acid compound represented by formula (B) is not limited to a specific compound and includes, for example, at least one selected from the group consisting of phenyl salicylate, 4-butylphenyl salicylate, and octylphenyl salicylate.

[0037] The metal component is not limited to a specific metal component. The metal component is typically a component that does not aggregate in the light-absorbing composition and the light-absorbing film formed using the light-absorbing composition, and is thermally and chemically stable. In addition, the metal component is typically a component that can interact with the above-mentioned ultraviolet absorber.

[0038] The light-absorbing composition may contain a predetermined compound containing a metal component, such as a complex, and preferably contains an alkoxide containing a metal component.

[0039] The metal component includes at least one selected from the group consisting of, for example, Li, Na, Mg, Ca, Sr, Ba, Ge, Sn, Pb, Al, Ga, In, Tl, Zn, Cd, Cu, Ag, Au, Ni, Pd, Pt, Co, Rh, Ir, Fe, Mn, Cr, Mo, W, V, Nb, Ta, Ti, and Zr. In this case, the metal component is likely to interact with the ultraviolet absorber.

[0040] The content of the ultraviolet absorber in the light-absorbing composition is not limited to a specific value. The content is, for example, 0.05 to 10%, preferably 0.1 to 8%, and more preferably 0.2 to 6%, by mass. The content may be 3% or less, 2% or less, or 1% or less.

[0041] The content of the metal component in the light-absorbing composition is not limited to a particular value and is, for example, 0.005 to 5%, preferably 0.01 to 3%, and more preferably 0.02 to 2%, by mass.

[0042] In the light-absorbing composition, the ratio of the content of the ultraviolet absorber to the content of the metal component is not limited to a specific value. This ratio, on a mass basis, is, for example, 0.05 to 300, preferably 0.07 to 280, and more preferably 0.1 to 260. This ratio may be 240 or less, 200 or less, 150 or less, 100 or less, 50 or less, 40 or less, or 30 or less. Furthermore, the molar ratio of the content of the ultraviolet absorber to the content of the metal component is also not limited to a specific value. This molar ratio is, for example, 0.001 to 40, preferably 0.005 to 35, and more preferably 0.01 to 30. This molar ratio may be 25 or less, 20 or less, 15 or less, 10 or less, 5 or less, or 3 or less. This makes it possible for a light-absorbing film or optical filter produced using the light-absorbing composition to more reliably and effectively absorb light in the short wavelength region around 400 nm.

[0043] The light-absorbing composition may further contain a curable resin. In this case, a light-absorbing film containing an ultraviolet absorber and a metal component can be formed by curing the resin in the light-absorbing composition. In addition, for example, by applying the light-absorbing composition to a predetermined substrate and curing the resin, an article having a substrate and having desired light absorption properties can be produced.

[0044] The curable resin is not limited to a specific resin, and may be, for example, an acrylic resin, an epoxy resin, a polycarbonate resin, a polyether resin, a polyester resin, a cyclic olefin resin, a silicone resin, or a polyvinyl acetal (PVA) resin.

[0045] The resin is preferably a silicone resin. More preferably, the resin is a silicone resin containing an aryl group such as a phenyl group. If the resin contained in the light-absorbing film is hard (rigid), cracks are more likely to occur due to cure shrinkage during the production of the light-absorbing film as the thickness of the layer containing the resin increases. If the resin is a silicone resin containing an aryl group, the light-absorbing film formed from the light-absorbing composition is more likely to have good crack resistance. Furthermore, silicone resins containing aryl groups tend to have high compatibility or dispersibility with metal components and UV absorbers, and are less likely to cause aggregation of these components. 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. These are all silicone resins manufactured by Shin-Etsu Chemical Co., Ltd. Silicone resins tend to have high heat resistance. Since the light-absorbing composition contains a silicone resin, it is expected that a light-absorbing film obtained using the light-absorbing composition will also contain a silicone resin and have heat resistance. From this perspective, it is advantageous for the light-absorbing composition to contain a silicone resin as a curable resin.

[0046] In the light-absorbing composition, the ratio of the content of the ultraviolet absorber to the content of the solid content of the resin is not limited to a specific value. This ratio is, for example, 0.1% to 10%, preferably 0.2% to 5%, and more preferably 0.4% to 3%, by mass. This is advantageous from the viewpoint of suppressing problems such as a decrease in weather resistance or bleed-out.

[0047] The resin may preferably be a PVA resin. The PVA resin is more preferably a polyvinyl butyral (PVB) resin or a polyvinyl formal (PVF) resin. These resins are obtained by the reaction of polyvinyl alcohol with an aldehyde. PVB resin and PVF resin contain, in addition to butyral or formal groups, acetyl groups and hydroxyl groups bonded to the vinyl groups. These resins may have the advantage of good affinity with metal components due to the contribution of some of the hydroxyl groups contained therein. PVB resin and PVF resin can contain a relatively large amount of ultraviolet absorber, and the resin composition after curing tends to have high flexibility and durability.

[0048] Specific examples of PVB resins are S-LEC KS-1, KS-3, KS-5, KX-1, BL-1, BL-S, and BX-L. These are all PVA resins (PVB resins) manufactured by Sekisui Chemical Co., Ltd., and S-LEC is a registered trademark. Other specific examples of PVB resins are Mobital B20H, B30T, B30H, and B45H. These are all PVA resins (PVB resins) manufactured by Kuraray Co., Ltd., and Mobital is a registered trademark. Specific examples of PVF resins are Vinylec K and Vinylec H. These are all PVA resins (PVF resins) manufactured by JNC Corporation, and Vinylec is a registered trademark. Since the light-absorbing composition contains a PVA resin, a light-absorbing film obtained using the light-absorbing composition also contains a PVA resin and is likely to have flexibility and durability. In particular, PVB resin has been widely used as an interlayer film for automobile windshields, and is expected to have high transparency and non-yellowing properties.

[0049] PVB resins and PVF resins, including the products listed in the specific examples above, are often available in powder form. To incorporate PVB resins and PVF resins into liquid resin compositions, they are dissolved in an appropriate amount in, for example, (I) alcohol-based solvents such as methanol, ethanol, n-propanol, isopropanol, and n-butanol; (II) aromatic solvents such as toluene, cyclopentanone, and xylene; (III) ketone-based solvents such as methyl ethyl ketone (MEK), methyl butyl ketone (MBK), and ethyl acetate; (IV) ester-based solvents such as ethyl acetate, n-propyl acetate, isopropyl acetate, and isobutyl acetate; (V) glycol ester-based organic solvents such as propylene glycol monomethyl ether acetate; or (VI) glycol ether-based organic solvents such as propylene glycol monomethyl ether and dipropylene glycol methyl ether. These organic solvents may be used alone or in combination. Among these, the organic solvent is preferably an aromatic organic solvent, an alcoholic organic solvent, or a mixture thereof, more preferably a mixture of an aromatic organic solvent and an alcoholic organic solvent, because it has excellent transparency and the resin solution is stable over time. In this case, the aromatic organic solvent is preferably toluene, and the alcoholic organic solvent is preferably ethanol or propanol, more preferably ethanol. Furthermore, when a mixture of an aromatic organic solvent and an alcoholic organic solvent is used as the organic solvent, it is preferably used under the condition that the mass ratio of the aromatic organic solvent to the alcoholic organic solvent is 1:0.1 to 10, and more preferably the mass ratio of the aromatic organic solvent to the alcoholic organic solvent is 1:0.5 to 5. From the viewpoint of solubility in various solvents, PVB resin is preferably used.

[0050] It is advantageous for a light-absorbing composition to contain an ultraviolet absorber having a hydroxy group and a carbonyl group in its molecule, a metal component, and a PVA resin in terms of suppressing bleed-out of the ultraviolet absorber. When an additive-type ultraviolet absorber is contained in the PVB resin, the ultraviolet absorber may powder or float to the surface of the light-absorbing film or optical film, depending on the conditions of the usage environment and the method of producing the light-absorbing film. When a light-absorbing composition or light-absorbing film contains an ultraviolet absorber having a hydroxy group and a carbonyl group in its molecule, a metal component, and a PVA resin, the ultraviolet absorber, partially bonded to the metal component by complexation or the like, is more likely to bond to some of the hydroxyl groups of the PVA resin via the metal component. As a result, the ultraviolet absorber is relatively strongly retained within the resin matrix, which tends to suppress bleed-out of the ultraviolet absorber.

[0051] An example of a method for preparing a light-absorbing composition will be described. An ultraviolet absorber is added to a predetermined solvent and stirred to prepare a solution of the ultraviolet absorber. In addition, a compound containing a metal component and a resin are mixed and stirred to prepare a liquid composition containing the metal component. The light-absorbing composition can be prepared by mixing and stirring the solution of the ultraviolet absorber and the liquid composition containing the metal component in predetermined amounts.

[0052] The light-absorbing composition may be a liquid composition containing a PVB resin. This liquid composition typically contains a solvent that dissolves or disperses the PVB in the liquid. This solvent is not limited to a specific solvent, but when selecting a solvent for dissolving the PVB, an organic solvent may be used as the solvent, taking into consideration the solubility of PVB. The concentration of PVB in the liquid composition is not limited to a specific value. The concentration is set appropriately taking into consideration the solubility of PVB in the solvent. The concentration is, for example, about 10 to 50 mass %.

[0053] The light-absorbing composition can be used to provide, for example, a light-absorbing film 10 as shown in FIG. 1 . The light-absorbing film 10 can be obtained, for example, by curing a coating of the light-absorbing composition. The light-absorbing film 10 contains a UV absorber having a hydroxy group and a carbonyl group in its molecule, and a metal component. In the light-absorbing film 10, at least a portion of the metal component is bonded to an organic oxy group. At least a portion of the metal component is bonded to an oxygen atom in the organic oxy group. This makes it easier for the light-absorbing film 10 to effectively absorb light in the short wavelength region around 400 nm.

[0054] As described above, in the light-absorbing composition, at least a portion of the metal component is bonded to an organic oxy group and typically exists in the form of M-O-R, where R represents a specific organic group, such as an alkyl group, an aryl group, or a vinyl group.

[0055] In the ultraviolet absorber of the light-absorbing film 10, the hydroxy group and the carbonyl group are preferably spaced apart by 1 to 3 atoms, which makes it easier for the light-absorbing film 10 to more reliably absorb light with a wavelength of around 400 nm effectively and appropriately.

[0056] The ultraviolet absorber in the light-absorbing film 10 includes, for example, a benzophenone-based compound represented by the above formula (A1), which makes it easier for the light-absorbing film 10 to more reliably and effectively absorb light in the short wavelength region around 400 nm.

[0057] The ultraviolet absorber in the light-absorbing film 10 preferably contains a benzophenone-based compound represented by the above formula (A2), which makes it easier for the light-absorbing film 10 to more reliably absorb light in the short wavelength region around 400 nm effectively.

[0058] The ultraviolet absorber in the light-absorbing film 10 includes, for example, a salicylic acid-based compound represented by the above formula (B), which makes it easier for the light-absorbing film 10 to more reliably and effectively absorb light in the short wavelength region around 400 nm.

[0059] The light absorbing film 10 contains, for example, an alkoxide containing a metal component.

[0060] The metal component in the light absorbing film 10 includes at least one selected from the group consisting of, for example, Li, Na, Mg, Ca, Sr, Ba, Ge, Sn, Pb, Al, Ga, In, Tl, Zn, Cd, Cu, Ag, Au, Ni, Pd, Pt, Co, Rh, Ir, Fe, Mn, Cr, Mo, W, V, Nb, Ta, Ti, and Zr.

[0061] The content of the ultraviolet absorber in the light-absorbing film 10 is not limited to a specific value and is, for example, 0.1% to 10%, preferably 0.2% to 5%, and more preferably 0.4% to 3%, by mass.

[0062] The content of the metal component in the light absorbing film 10 is not limited to a specific value. The content is, for example, 0.02% to 5%, preferably 0.04% to 4%, and more preferably 0.06% to 3.5%, by mass.

[0063] The thickness of the light-absorbing film 10 is not limited to a specific value and may be, for example, 10 μm to 600 μm, 10 μm to 400 μm, or 10 μm to 300 μm.

[0064] In the transmission spectrum of the light absorbing film 10 at an incident angle of 0 degrees, the transmittance T 400 is, for example, 5% or less.

[0065] In the production of the light-absorbing film 10, the method for curing the light-absorbing composition is not limited to a specific method. For example, the light-absorbing composition may be cured by heating it at a predetermined temperature. In this case, the predetermined temperature is not limited to a specific temperature as long as it is possible to cure the light-absorbing composition. The predetermined temperature is, for example, 85°C or higher, preferably 120°C or higher, more preferably 140°C or higher, and even more preferably 150 to 160°C. This makes it easier for the light-absorbing film 10 to have good heat resistance while preventing deterioration of the ultraviolet absorber.

[0066] Transmittance T 400 is preferably 3% or less, and more preferably 1% or less.

[0067] 1 and 2, for example, optical filters 1a and 1b can be provided that include a light absorbing film 10. The optical filters 1a and 1b tend to effectively absorb light in the short wavelength region around 400 nm.

[0068] In the transmission spectrum of the optical filters 1a and 1b at an incident angle of 0 degrees, the maximum value T of the transmittance in the wavelength range of 300 to 380 nm M 300-380 is, for example, 3% or less, which makes it easier for the optical filter to effectively absorb light in the short wavelength region around 400 nm.

[0069] Maximum transmittance T M 300-380 is preferably 2% or less, and more preferably 1% or less.

[0070] In the transmission spectrum of the optical filters 1a and 1b at an incident angle of 0 degrees, the wavelength at which the transmittance is 50% in the wavelength range of 300 to 520 nm is defined as the ultraviolet cutoff wavelength λ UV In the optical filters 1a and 1b, for example, 405 nm≦λ UV ≦500 nm is satisfied, which makes it easier for the light absorbing film 10 to effectively absorb light in the short wavelength region around 400 nm.

[0071] The optical filters 1a and 1b preferably have a wavelength of 405 nm≦λ UV ≦490 nm, and more preferably 405 nm≦λ UV The condition of ≦480 nm is met.

[0072] In the transmission spectra of the optical filters 1a and 1b at an incident angle of 0 degrees, the average transmittance T in the wavelength range of 550 to 570 nm A 550-570 is, for example, 87% or more. This allows the optical filters 1a and 1b to appropriately transmit visible light, which is advantageous from the perspective of reproducing the visual sensitivity of humans.

[0073] Average transmittance T A 550-570 is preferably 88% or more, and more preferably 90% or more.

[0074] The transmission spectrum obtained by irradiating light having a wavelength in the range of 300 nm to 1200 nm onto the optical filters 1a and 1b at an incident angle of 0° may satisfy the following requirements (ia), (ii-a), (iii-a), (iv-a), (va), and (vi-a): (ia) The maximum value T of the transmittance in the wavelength range of 300 nm to 380 nm M 300-380 (ii-a) Transmittance T at a wavelength of 400 nm 400 (iii-a) Transmittance T at a wavelength of 410 nm 410 (iv-a) The wavelength λ at which the transmittance becomes 50% within the wavelength range of 350 nm to 500 nm UV [nm] is in the range of 405 nm to 490 nm. (va) The average value T of the transmittance at wavelengths of 550 nm to 570 nm A 550-570 is 87% or more. (vi-a) Wavelength (λ UV -10) Transmittance T at nm 0 UV- For the wavelength (λ UV +10) Transmittance T at nm 0 UV+ The ratio T 0 UV+ / T 0 UV- is 1.8 or more.

[0075] By satisfying the above requirement (ia), the optical filters 1a and 1b can exhibit high ultraviolet absorption. M 300-380 is more preferably 2% or less, even more preferably 1% or less, particularly preferably 0.5% or less, and especially preferably 0.3% or less.

[0076] By satisfying the requirements (ii-a) and (iii-a) above in addition to the requirement (ia), the optical filters 1a and 1b can exhibit higher ultraviolet absorption properties. In particular, the optical filters 1a and 1b can be applied to optical filter applications that require higher ultraviolet absorption performance. 400is preferably 4% or less, more preferably 3% or less, and even more preferably 1% or less. 410 is preferably 9% or less, more preferably 8% or less, even more preferably 6% or less, particularly preferably 3% or less, and especially preferably 1% or less.

[0077] By satisfying the above requirement (iv-a), the optical filters 1a and 1b can exhibit high ultraviolet absorption properties, and the spectrum perceived by the imaging element can easily match the spectrum corresponding to the human visual sensitivity. UV is preferably 420 nm to 490 nm, and more preferably 420 nm to 450 nm. In this case, purple fringing is easily suppressed in the obtained image. Purple fringing is a color bleeding that appears approximately purple, particularly around the contours of a subject. In addition, the transmittance of light in the human visible light range can be increased, making it easier to obtain bright images.

[0078] By satisfying the above requirement (va), the transmittance of light in the human visible light range tends to be high, making it easier to obtain bright images. In particular, the transmittance of the wavelength range corresponding to the maximum sensitivity on the human luminosity curve tends to be high, making it easier for humans to perceive brightness when viewing an image. Average value T A 550-570 is preferably 88% or more, and more preferably 90% or more.

[0079] By satisfying the above requirement (vi-a), the wavelength λ UV Since the transmission spectrum changes sharply in the vicinity of the UV cutoff wavelength, ultraviolet rays that are invisible to humans can be more sharply blocked, and the amount of light included in the visible light range can be increased. 0 UV+ / T 0 UV- is preferably 1.9 or more, more preferably 2.0 or more, even more preferably 2.2 or more, and particularly preferably 2.4 or more.

[0080] The reflection spectrum obtained by irradiating light having a wavelength in the range of 300 nm to 1200 nm onto the optical filters 1a and 1b at an incident angle of 5° may satisfy the following requirements (ib) and (ii-b). In addition, the reflection spectrum obtained by irradiating light having a wavelength in the range of 300 nm to 1200 nm onto the optical filters 1a and 1b at an incident angle of 40° may satisfy the following requirements (iii-b) and (iv-b). Furthermore, the reflection spectrum obtained by irradiating light having a wavelength in the range of 300 nm to 1200 nm onto the optical filters 1a and 1b at an incident angle of 60° may satisfy the following requirements (vb) and (vi-b). (ib) The maximum value R of reflectance in the wavelength range of 300 nm to 450 nm 5 300-450 (ii-b) The maximum reflectance R in the wavelength range of 300 nm to 600 nm 5 300-600 (iii-b) The maximum reflectance R in the wavelength range of 300 nm to 450 nm 40 300-450 (iv-b) The maximum reflectance R in the wavelength range of 300 nm to 600 nm 40 300-600 (vb) The maximum reflectance R in the wavelength range of 300 nm to 450 nm 60 300-450 (vi-b) The maximum reflectance R in the wavelength range of 300 nm to 600 nm 60 300-600 is less than 35%.

[0081] Satisfying the above requirements (ib) to (vi-b) is extremely advantageous from the viewpoint of preventing ghosts, flares, or noise that occur when light reflected from the surfaces of the optical filters 1a and 1b is multiple-scattered, for example, inside or at the edges of a camera module or a housing. 5 300-450 is preferably 15% or less. 40 300-450 is preferably 15% or less. 60 300-450 is preferably 20% or less. 5300-600 is preferably 20% or less. 40 300-600 is preferably 20% or less. 60 300-600 is preferably 25% or less.

[0082] The optical filters 1a and 1b may satisfy the following requirements (ic), (ii-c), (iii-c), (iv-c), and (vc): λ of (ic) 30 UV [nm] is the wavelength at which the transmittance is 50% within the wavelength range of 350 nm to 500 nm in the transmission spectrum when light in the wavelength range of 300 nm to 1200 nm is incident on the optical filter at an incident angle of 30°. 40 UV [nm] is the wavelength at which the transmittance is 50% within the wavelength range of 350 nm to 500 nm in the transmission spectrum when light in the wavelength range of 300 nm to 1200 nm is incident on the optical filter at an incident angle of 40°. 50 UV [nm] is the wavelength at which the transmittance is 50% within the wavelength range of 350 nm to 500 nm in the transmission spectrum when light in the wavelength range of 300 nm to 1200 nm is incident on the optical filter at an incident angle of 50°. 60 UV [nm] is the wavelength at which the transmittance is 50% within the wavelength range of 350 nm to 500 nm in the transmission spectrum when light in the wavelength range of 300 nm to 1200 nm is incident on the optical filter at an incident angle of 60°. 70 UV [nm] is the wavelength at which the transmittance is 50% within the wavelength range of 350 nm to 500 nm in the transmission spectrum when light in the wavelength range of 300 nm to 1200 nm is incident on the optical filter at an incident angle of 70°. 30 UV -λ UV |≦2.4nm (ii-c) |λ 40 UV -λ UV |≦3.0nm (iii-c) |λ 50 UV-λ UV |≦5.0nm (iv-c) |λ 60 UV -λ UV |≦9.0nm (vc)|λ 70 UV -λ UV |≦18.0 nm

[0083] A complete absorption type UV cut filter can have the advantage of having a small angular dependency of its transmission spectrum. UV cut filters that use a reflective film to cut UV rays tend to have a UV cutoff wavelength that shifts toward shorter wavelengths for light incident at an angle. This means that the UV light to be cut may be detected by a sensor depending on the angle of incidence. On the other hand, optical filters 1a and 1b satisfy the above requirements (ic) to (vc), exhibiting little change in UV cutoff wavelength for oblique incidence and being less likely to shift the UV cutoff wavelength toward shorter wavelengths. Therefore, optical filters 1a and 1b not only suppress ghosting and flare, but also facilitate good color reproducibility with minimal in-plane color unevenness, making it easier to obtain high-quality images.

[0084] With respect to (ic), |λ 30 UV -λ UV | is preferably |λ 30 UV -λ UV |≦1.6 nm, and more preferably |λ 30 UV -λ UV |≦1.2 nm. Regarding (ii-c), |λ 40 UV -λ UV | is preferably |λ 40 UV -λ UV |≦2.0 nm, and more preferably |λ 40 UV -λ UV |≦1.5 nm. Regarding (iii-c), |λ 50 UV -λ UV | is preferably |λ 50 UV -λ UV|≦3.5 nm, and more preferably |λ 50 UV -λ UV |≦2.5 nm. Regarding (iv-c), |λ 60 UV -λ UV | is preferably |λ 60 UV -λ UV |≦6.0 nm, and more preferably |λ 60 UV -λ UV |≦4.5 nm. With respect to (vc), |λ 70 UV -λ UV | is preferably |λ 70 UV -λ UV |≦12.0 nm, and more preferably |λ 70 UV -λ UV |≦9.0 nm.

[0085] The optical filters 1a and 1b may satisfy the following requirements (id), (ii-d), and (iii-d): m 480-600 is the minimum value of the transmittance in the wavelength range of 480 nm to 600 nm in the transmission spectrum of the optical filter at an incident angle of 0° before the start of the high-temperature, high-humidity test and the heat cycle test. The high-temperature, high-humidity test is performed under conditions of a temperature of 85°C and a relative humidity of 85%. DH-240 UV [nm] is the wavelength at which the transmittance in the wavelength range of 350 nm to 500 nm becomes 50% in the transmission spectrum of the optical filter at an incident angle of 0° after 240 hours have passed since the start of the high-temperature, high-humidity test, and T DH-240 480-600 is the minimum value of the transmittance in the wavelength range of 480 nm to 600 nm in the transmission spectrum. DH-480 UV [nm] is the wavelength at which the transmittance in the wavelength range of 350 nm to 500 nm becomes 50% in the transmission spectrum of the optical filter at an incident angle of 0° after 480 hours have passed since the start of the high-temperature, high-humidity test, and T DH-480 480-600is the minimum value of the transmittance in the wavelength range of 480 nm to 600 nm in the transmission spectrum. DH-1K UV [nm] is the wavelength at which the transmittance in the wavelength range of 350 nm to 500 nm becomes 50% in the transmission spectrum of the optical filter at an incident angle of 0° after 1008 hours have elapsed since the start of the high-temperature, high-humidity test, and T DH-1K 480-600 is the minimum value of the transmittance in the wavelength range of 480 nm to 600 nm in the transmission spectrum. DH-240 UV -λ UV |≦3 nm and |T DH-240 480-600 -T m 480-600 |≦2% (ii-d)|λ DH-480 UV -λ UV |≦3.5 nm and |T DH-480 480-600 -T m 480-600 |≦2.5% (iii-d) |λ DH-1K UV -λ UV |≦4 nm and |T DH-1K 480-600 -T m 480-600 |≦3%

[0086] When the optical filters 1a and 1b satisfy the requirements (id), (ii-d), and (iii-d), the optical filters 1a and 1b can exhibit high ultraviolet absorption even in a high-temperature, high-humidity environment, and the spectrum perceived by the imaging element tends to match the spectrum corresponding to human visual sensitivity. In addition, even in a high-temperature, high-humidity environment, the transmittance of light in the human visible light range tends to be high, making it easier to obtain bright images.

[0087] The optical filters 1a and 1b may satisfy the following requirements (ie), (ii-e), and (iii-e): m 480-600is the minimum value of the transmittance in the wavelength range of 480 nm to 600 nm in the transmission spectrum of the optical filter at an incident angle of 0° before the start of the high-temperature, high-humidity test and the heat cycle test. The heat cycle test is a test that includes, as one cycle, maintaining the environmental temperature at 85°C for 30 minutes, changing the environmental temperature from 85°C to -40°C over 5 minutes, maintaining the environmental temperature at -40°C for 30 minutes, and changing the environmental temperature from -40°C to 85°C over 5 minutes, in this order. λ of (ie) HC-144 UV [nm] is the wavelength at which the transmittance becomes 50% within the wavelength range of 350 nm to 500 nm in the transmission spectrum of the optical filter at an incident angle of 0° after 144 cycles in the heat cycle test, and T HC-144 480-600 is the minimum value of the transmittance in the wavelength range of 480 nm to 600 nm in the transmission spectrum. HC-576 UV [nm] is the wavelength at which the transmittance becomes 50% within the wavelength range of 350 nm to 500 nm in the transmission spectrum of the optical filter at an incident angle of 0° after 576 cycles in the heat cycle test, and T HC-576 480-600 is the minimum value of the transmittance in the wavelength range of 480 nm to 600 nm in the transmission spectrum. HC-1K UV [nm] is the wavelength at which the transmittance becomes 50% within the wavelength range of 350 nm to 500 nm in the transmission spectrum of the optical filter at an incident angle of 0° after 1008 cycles in the heat cycle test, and T HC-1K 480-600 is the minimum value of the transmittance in the wavelength range of 480 nm to 600 nm in the transmission spectrum. HC-144 UV -λ UV |≦3 nm and |T HC-144 480-600 -T m 480-600 |≦2% (ii-e)|λ HC-576 UV -λ UV |≦3.5 nm, and |T HC-576 480-600 -T m480-600 |≦2.5% (iii-e)|λ HC-1K UV -λ UV |≦4 nm, and |T HC-1K 480-600 -T m 480-600 |≦3%

[0088] If the optical filters 1a and 1b satisfy the requirements (i), (ii-e), and (iii-e), the optical filters 1a and 1b can exhibit high ultraviolet absorption even if the temperature of the environment of the optical filters 1a and 1b changes, and the spectrum sensitive to the imaging element tends to match the spectrum corresponding to the human visual sensitivity. In addition, even if the temperature of the environment of the optical filters 1a and 1b changes, the transmittance of light belonging to the human visible light range tends to be high, making it easier to obtain bright images.

[0089] The optical filter 1a is, for example, composed of a single light-absorbing film 10. In this case, the optical filter 1a can be used, for example, separately from an imaging element or an optical component. The optical filter 1a may be bonded to the imaging element and the optical component. On the other hand, the optical filter 1a may be constructed by applying the above-mentioned light-absorbing composition to the imaging element or the optical component and curing the light-absorbing composition.

[0090] The optical filter 1a can be produced, for example, by peeling off the light-absorbing film 10 formed on a 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 a surface treatment such as coating with a fluorine-containing compound.

[0091] 2A , the optical filter 1b includes a light-absorbing film 10 and a transparent dielectric substrate 20. The light-absorbing film 10 is provided parallel to one main surface of the transparent dielectric substrate 20. The light-absorbing 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 to one main surface of the transparent dielectric substrate 20 and curing the light-absorbing composition.

[0092] The type of transparent dielectric substrate 20 is not limited to a specific type. The transparent dielectric substrate 20 may have absorption 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 specific glass or resin. When the transparent dielectric substrate 20 is made of glass, the transparent dielectric substrate 20 may be, for example, transparent glass made of silicate glass such as soda-lime glass or borosilicate glass, or phosphate glass or fluorophosphate glass containing coloring components such as Cu and Co. Phosphate glass and fluorophosphate glass containing coloring components are, for example, infrared-absorbing glass and are themselves light-absorbing. When the light-absorbing film 10 is used together with a 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 with desired optical characteristics, allowing for greater freedom in designing the optical filter.

[0093] When the material of the transparent dielectric substrate 20 is a resin, the resin is, 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, a polysulfone resin, a polyethersulfone resin, a polycarbonate resin, or a silicone resin.

[0094] Each of the optical filters 1a and 1b may be modified to further include other functional films, such as an infrared absorbing film, an infrared reflective film, and an anti-reflection film. Such functional films may be provided on the light absorbing film 10 or the transparent dielectric substrate 20. For example, the optical filter may include an anti-reflection film to increase the transmittance of a predetermined wavelength range (e.g., the visible light range). The anti-reflection film may be configured as a layer of a low-refractive index material such as MgF2 and SiO2, or as a laminate of a layer of such a low-refractive index material and a layer of a high-refractive index material such as TiO2, or as a dielectric multilayer film. Such anti-reflection films may be formed by methods involving physical reactions, such as vacuum deposition and sputtering, or by methods involving chemical reactions, such as CVD and sol-gel processes.

[0095] The optical filter may be configured, for example, by disposing the light-absorbing film 10 between two glass plates. This improves the rigidity and mechanical strength of the optical filter. In addition, the main surface of the optical filter becomes hard, which is advantageous from the viewpoint of preventing scratches, etc. This advantage is particularly important when a relatively flexible resin is used as the binder or matrix in the light-absorbing film 10.

[0096] By providing an antireflection film on the surface of the light-absorbing film and optical filter obtained by curing the light-absorbing composition, an optical filter with even better optical properties can be provided. For example, as shown in FIG. 2B, an optical filter 1c can be provided that includes a light-absorbing film 10 and an antireflection film 30. In an optical filter having an antireflection film formed thereon, when light is incident on the optical filter at a predetermined angle of incidence, the amount of light reflected from the optical filter is reduced, approaching zero. This is extremely advantageous in an imaging device equipped with an optical filter having an antireflection film formed thereon, from the perspective of preventing ghosts, flare, and noise caused by multiple scattering of reflected light within the imaging device or camera module, for example.

[0097] The material of the anti-reflection film is not limited to a specific material. The method for forming the anti-reflection film is not limited to a specific method. The method for forming the anti-reflection film may be a gas phase method or a liquid phase method. For example, the method for forming the anti-reflection film may be a vapor deposition method. The method for forming the anti-reflection film may be a sol-gel method using a reactive material containing silicon, which is a liquid phase method that is excellent for forming anti-reflection films.

[0098] Antireflective coatings can be single-layer films made of the same material or multilayer films made of two or more different materials. The materials constituting each layer of the film and multilayer film are not limited to specific materials. Examples of such materials include inorganic compounds such as SiO2, TiO2, Ta2O3, MgF2, Al2O3, CaF2, ZrO2, CeO2, and ZnS. For example, when an antireflective coating or a layer contained in an antireflective coating contains SiO2, the film or layer may be formed by the so-called sol-gel method using an alkoxysilane compound as the starting material. The sol-gel method involves hydrolysis of the alkoxysilane compound in the presence of water and a catalyst, followed by condensation polymerization, resulting in a dense, hard film containing SiO2. The sol-gel method has the advantage of being able to form a film or layer containing SiO2 without requiring high temperatures.

[0099] When forming an anti-reflective coating using the sol-gel method, the starting material is not limited to a specific material, and the functional groups contained in the starting material are also not limited to a specific functional group. The starting material preferably includes a "trifunctional silane containing an alkyl group" such as MTES (methyltriethoxysilane) and TEOS (tetraethoxysilane), and a "tetrafunctional silane." Tetrafunctional silanes are essential for forming a film or layer with a strong and dense skeleton. However, using tetrafunctional silanes alone makes it difficult to control the reactivity and adjust the polarity of the film or layer. In addition, cracks are likely to occur in the film or layer. When the starting material contains a trifunctional silane in addition to a tetrafunctional silane, the flexibility of the silica skeleton is improved, making it easier to adjust the polarity of the film or layer and reducing cracking in the film or layer. Easily adjusting the polarity of the film or layer is desirable from the perspective of adjusting the refractive index of the anti-reflective coating. The organic functional groups in the trifunctional silane are not inherently limited to a specific functional group. In particular, trifunctional silanes having methyl groups as organic functional groups are desirable in order to form homogeneous liquids and coating films when combined with tetrafunctional silanes.

[0100] In the starting material, the ratio of the amount of "trifunctional silane containing an alkyl group" to the amount of "tetrafunctional silane" is not limited to a specific value. Desirably, in the starting material, the relationship of the amount of "trifunctional silane containing an alkyl group" to the amount of "tetrafunctional silane" is satisfied, based on mass, from 5:1 to 1:3. This facilitates the suppression of cracks in the antireflective coating, and facilitates the formation of a strong skeleton by the tetrafunctional silane. The starting material may contain components other than those involved in the sol-gel process. For example, the starting material may contain fine particles and a filler for adjusting the refractive index. In this case, the fine particles and the filler may be hollow or may be a high refractive index material. The starting material may contain a component that decomposes at a low temperature. This facilitates the adjustment of the refractive index of the antireflective coating. The temperature at which the coating is baked in the sol-gel process is not limited to a specific temperature. The temperature is, for example, in the range of 60°C to 250°C, preferably in the range of 70°C to 230°C, and more preferably in the range of 80°C to 200°C. Since the light absorbing film and the optical filter can have high heat resistance, no problems arise when baking the coating film in the sol-gel method, and a strong anti-reflection film can be easily formed.

[0101] When the antireflective coating is a single-layer coating, it is desirable that the material of the single-layer coating have a low refractive index. The refractive index n1 of the antireflective coating material tends to be lowest when n1 = √n0. n0 is the refractive index of the substrate used to form the antireflective coating. For example, when the antireflective coating contains hollow particles formed from metal oxides such as SiO2 and TiO2 or organic materials such as PMMA, the interior of the hollow particles is occupied by air, which has a refractive index of approximately 1, and the refractive index of the antireflective coating tends to be low. If the refractive index required for the antireflective coating is not too low, the antireflective coating may contain solid particles formed from the above materials. If the antireflective coating requires mechanical strength such as scratch resistance, it is advantageous for the antireflective coating to contain such solid particles. A film may be formed by a sol-gel method while containing such hollow or solid particles. In particular, when hollow or solid particles made of SiO2 are used, there is a good affinity between the SiO2 in the film formed by the sol-gel method and the hollow or solid particles, which is expected to suppress aggregation of the hollow or solid particles and to suppress bleed-out, etc.

[0102] The antireflection coating may have a multilayer structure including a layer containing SiO formed by a sol-gel method and a layer formed by, for example, vacuum deposition, sol-gel, or other methods. For example, by forming the antireflection coating into a multilayer structure using two or more materials with different refractive indices, the wavelength band in which the antireflection effect is obtained is likely to be relatively wide, and the minimum reflectance value in the optical filter is likely to be low. When the antireflection coating is combined with a layer containing SiO formed by a sol-gel method to form a multilayer structure, the combined layer may be, for example, a layer containing hollow particles and containing SiO formed by a sol-gel method, a layer made of a material with a relatively high refractive index such as TiO or TaO, or a layer made of another material such as MgF.

[0103] As shown in FIG. 2B, for example, the light incident surface and light exit surface of the optical filter 1c are formed by an anti-reflection film 30. In other words, the optical filter 1c is provided with the anti-reflection film 30 on, for example, both surfaces thereof. The anti-reflection film 30 contains, for example, SiO2. The transmission spectrum obtained when light having a wavelength in the range of 300 nm to 1200 nm is incident on the optical filter 1c at an incident angle of 0° satisfies, for example, the following requirements (if), (ii-f), (iii-f), (iv-f), (vf), (vi-f), and (vii-f): (if) Maximum transmittance Tb in the wavelength range of 300 nm to 380 nm M 300-380 (ii-f) Transmittance Tb at a wavelength of 400 nm 400 (iii-f) Transmittance Tb at a wavelength of 410 nm 410 (iv-f) The wavelength λb at which the transmittance becomes 50% within the wavelength range of 350 nm to 500 nm UV [nm] is in the range of 405 nm to 490 nm. (vf) The minimum value Tb of the transmittance in the wavelength range of 480 nm to 600 nm m 480-600 (vi-f) The average transmittance Tb in the wavelength range of 550 nm to 570 nm a550-570 (vii-f) Wavelength (λb UV -10) Transmittance Tb at nm 0 UV- For wavelength (λb UV +10) Transmittance Tb at nm 0 UV+ Ratio Tb 0 UV+ / Tb 0 UV- is 2.5 or more.

[0104] The reflection spectrum obtained by making light having a wavelength of 300 nm to 1200 nm incident on the optical filter 1c at an incident angle of 5° satisfies, for example, the requirements (ig) and (ii-g) below. The reflection spectrum obtained by making light having a wavelength of 300 nm to 1200 nm incident on the optical filter 1c at an incident angle of 40° satisfies, for example, the requirements (iii-g) and (iv-g) below. The reflection spectrum obtained by making light having a wavelength of 300 nm to 1200 nm incident on the optical filter 1c at an incident angle of 60° satisfies, for example, the requirements (vg) and (vi-g) below. (ig) Maximum reflectance R in the wavelength range of 300 nm to 450 nm 5 300-450 (ii-g) The maximum reflectance R in the wavelength range of 300 nm to 600 nm 5 300-600 (iii-g) The maximum reflectance R in the wavelength range of 300 nm to 450 nm 40 300-450 (iv-g) The maximum reflectance R in the wavelength range of 300 nm to 600 nm 40 300-600 (vg) The maximum reflectance R in the wavelength range of 300 nm to 450 nm 60 300-450 (vi-g) The maximum reflectance R in the wavelength range of 300 nm to 600 nm 60 300-600 is less than 14%.

[0105] The present invention will be described in more detail with reference to examples. Note that the present invention is not limited to the following examples. First, the evaluation method of the optical filters according to each example and each comparative example will be described.

[0106] <Transmission Spectrum Measurement> The transmission spectrum and reflection spectrum of each optical filter were measured at a predetermined angle of incidence using an ultraviolet-visible-near-infrared spectrophotometer (manufactured by JASCO Corporation, product name: V-670).

[0107] <Thickness Measurement> The distance to the surface of each optical filter was measured using a laser displacement meter (manufactured by Keyence Corporation, product name: LK-H008), and the thickness of the light-absorbing film was measured by subtracting the thickness of the transparent glass substrate.

[0108] <Ultraviolet Absorbent> The following ultraviolet absorbents were used in the production of the optical filters according to the examples and comparative examples.

[0109]

[0110] The structural formulas of the ultraviolet absorbers (1-i), (1-ii), (1-iii), and (1-iv) are represented by the following formulas (C), (D), (E), and (F), respectively.

[0111]

[0112]

[0113]

[0114]

[0115] <Compounds containing metal components> In producing the optical filters according to the examples and comparative example 5, the following compounds containing metal components were used.

[0116]

[0117] Example 1 5.0 g of ultraviolet absorber (1-i) and 95.0 g of ethanol were mixed and stirred for 30 minutes to obtain an ultraviolet absorber solution according to Example 1. Next, 99.38 g of silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KR-300) and 0.62 g of compound (2-i) containing a metal component were mixed and stirred for 30 minutes to obtain a metal component-containing liquid composition according to Example 1. 2.0 g of the ultraviolet absorber solution according to Example 1 and 10.0 g of the metal component-containing liquid composition according to Example 1 were mixed and stirred for 30 minutes to obtain a light-absorbing composition according to Example 1. The contents of each component and the mass ratios of the specified components in the ultraviolet absorber solution, metal component-containing liquid composition, and light-absorbing composition are shown in Table 3. The amount of solid content in the light-absorbing composition was determined on the assumption that the solid content in the silicone resin KR-300 was 50 mass % and the metal component content in the compound (2-i) containing a metal component was 6.5 mass %.

[0118] A light-absorbing composition was applied using a dispenser to a 40 mm x 40 mm area in the center of one main surface of a transparent glass substrate (manufactured by SCHOTT, product name: D263 T eco) made of borosilicate glass and measuring 76 mm x 76 mm x 0.21 mm, forming a coating film. The resulting coating film was thoroughly dried at room temperature and then heat-treated in an oven at 160°C for 1 hour to volatilize the solvent and harden the film, thereby obtaining a light-absorbing film according to Example 1 containing an ultraviolet absorber and a metal component. In this manner, an optical filter according to Example 1 including the light-absorbing film according to Example 1 was prepared. The transmission spectrum of the optical filter according to Example 1 is shown in Figure 3. The wavelength-transmittance characteristics and the thickness of the light-absorbing film obtained from Figure 3 are also shown in Table 5.

[0119] Example 2 2.0 g of the ultraviolet absorber (1-ii) and 98.0 g of toluene were mixed and stirred for 30 minutes to obtain an ultraviolet absorber solution according to Example 2. Next, 99.38 g of silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KR-300) and 0.62 g of a compound (2-i) containing a metal component were mixed and stirred for 30 minutes to obtain a metal component-containing liquid composition according to Example 2. 5.0 g of the ultraviolet absorber solution according to Example 2 and 10.0 g of the metal component-containing liquid composition according to Example 2 were mixed and stirred for 30 minutes to obtain a light-absorbing composition according to Example 2. The contents of each component and the mass ratios of the specified components in the ultraviolet absorber solution, metal component-containing liquid composition, and light-absorbing composition are shown in Table 3.

[0120] A coating of the light-absorbing composition was cured on a transparent glass substrate in the same manner as in Example 1, except that the light-absorbing composition of Example 2 was used instead of the light-absorbing composition of Example 1 and the heat treatment temperature was set to 120°C, thereby obtaining a light-absorbing film of Example 2. In this manner, an optical filter of Example 2 including the light-absorbing film of Example 2 was produced. The transmission spectrum of the optical filter of Example 2 is shown in Figure 4. Furthermore, the characteristics related to wavelength and transmittance as seen in Figure 4 and the thickness of the light-absorbing film are shown in Table 5.

[0121] Examples 3 and 4 Light-absorbing compositions according to Examples 3 and 4 were prepared in the same manner as in Example 2, except that the amounts of the ultraviolet absorber solution and the metal component-containing liquid composition added were changed as shown in Table 3. Except that the light-absorbing compositions according to Examples 3 and 4 were used instead of the light-absorbing composition according to Example 2, coatings of the light-absorbing compositions were cured on transparent glass substrates to form light-absorbing films according to Examples 3 and 4, respectively, and optical filters according to Examples 3 and 4 were produced. The transmission spectra of the optical filters according to Examples 3 and 4 are shown in Figures 5 and 6, respectively. Furthermore, the wavelength-transmittance characteristics and the thickness of the light-absorbing films obtained from Figures 5 and 6 are shown in Table 5.

[0122] Examples 5 to 8 The preparation of an ultraviolet absorber solution, a metal component-containing liquid composition, and a light-absorbing composition were carried out in the same manner as in Example 1, except that the types of components and the amounts of the components were adjusted as shown in Table 3, thereby obtaining light-absorbing compositions according to Examples 5 to 8. In Examples 5 to 8, a compound (2-ii) containing a metal component was used to prepare the metal component-containing liquid composition. In Examples 5 and 6, an ultraviolet absorber (1-i) was used to prepare the ultraviolet absorber solution, and in Examples 7 and 8, an ultraviolet absorber (1-ii) was used to prepare the ultraviolet absorber solution. The amount of solids in the light-absorbing composition was determined on the assumption that the content of the metal component in the metal component-containing compound (2-ii) was 11.3 mass%.

[0123] The optical filters of Examples 5 to 8 were produced by curing coatings of the light-absorbing compositions on transparent glass substrates to form the light-absorbing films of Examples 5 to 8, respectively, in the same manner as in Example 1, except that the light-absorbing compositions of Examples 5 to 8 were used instead of the light-absorbing composition of Example 1. The transmission spectra of the optical filters of Examples 5 to 8 are shown in Figures 7 to 10, respectively. Table 5 also shows the wavelength-transmittance characteristics and the thickness of the light-absorbing films observed from Figures 7 to 10.

[0124] Examples 9 to 19 The preparation of an ultraviolet absorber solution, a metal component-containing liquid composition, and a light-absorbing composition were carried out in the same manner as in Example 1, except that the types of components and the amounts of the components were adjusted as shown in Table 3, thereby obtaining the light-absorbing compositions of Examples 9 to 19. In Examples 9 to 17, an ultraviolet absorber (1-i) was used to prepare the ultraviolet absorber solution, and in Examples 18 and 19, an ultraviolet absorber (1-ii) was used to prepare the ultraviolet absorber solution. In Examples 9 to 19, a compound (2-iii) containing a metal component was used to prepare the metal component-containing liquid composition. The amount of solids in the light-absorbing composition was determined on the assumption that the content of the metal component in the metal component-containing compound (2-iii) was 13.2 mass%.

[0125] The optical filters of Examples 9 to 19 were produced by curing coatings of the light-absorbing compositions on transparent glass substrates to form light-absorbing films of Examples 9 to 19 in the same manner as in Example 1, except that the light-absorbing compositions of Examples 9 to 19 were used instead of the light-absorbing composition of Example 1. The transmission spectra of the optical filters of Examples 9 to 19 are shown in Figures 11 to 21, respectively. The wavelength-transmittance characteristics and the thickness of the light-absorbing films observed from Figures 11 to 21 are also shown in Table 5.

[0126] Example 20 A light-absorbing composition according to Example 20 was obtained in the same manner as in Example 1, except that the ultraviolet absorber solution according to Example 20 was prepared using ultraviolet absorber (1-iii) instead of ultraviolet absorber (1-i). A coating of the light-absorbing composition was cured on a transparent glass substrate to form a light-absorbing film according to Example 20 in the same manner as in Example 1, except that the light-absorbing composition according to Example 20 was used instead of the light-absorbing composition according to Example 1, and an optical filter according to Example 20 was produced. The transmission spectrum of the optical filter according to Example 20 is shown in FIG. 22. The wavelength-transmittance characteristics and the thickness of the light-absorbing film obtained from FIG. 22 are also shown in Table 5.

[0127] Comparative Example 1 2.0 g of the UV absorber solution according to Example 1 and 10.0 g of silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KR-300) were mixed and stirred for 30 minutes to obtain a light-absorbing composition according to Comparative Example 1. The contents of each component in the UV absorber solution and the light-absorbing composition and the mass ratios of the specified components are shown in Table 4. A coating of the light-absorbing composition was cured on a transparent glass substrate to form a light-absorbing film according to Comparative Example 1 in the same manner as in Example 1, except that the light-absorbing composition according to Comparative Example 1 was used instead of the light-absorbing composition according to Example 1, thereby producing an optical filter according to Comparative Example 1. The transmission spectrum of the optical filter according to Comparative Example 1 is shown in FIG. 23 . The wavelength-transmittance characteristics and the thickness of the light-absorbing film obtained from FIG. 23 are also shown in Table 5.

[0128] Comparative Example 2 5.0 g of the UV absorber solution according to Example 2 and 10.0 g of silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KR-300) were mixed and stirred for 30 minutes to obtain a light-absorbing composition according to Comparative Example 2. The contents of each component in the UV absorber solution and the light-absorbing composition and the mass ratios of the specified components are shown in Table 4. A coating of the light-absorbing composition was cured on a transparent glass substrate to form a light-absorbing film according to Comparative Example 2 in the same manner as in Example 1, except that the light-absorbing composition according to Comparative Example 2 was used instead of the light-absorbing composition according to Example 1, thereby producing an optical filter according to Comparative Example 2. The transmission spectrum of the optical filter according to Comparative Example 2 is shown in FIG. 24. The wavelength-transmittance characteristics and the thickness of the light-absorbing film obtained from FIG. 24 are also shown in Table 5.

[0129] Comparative Example 3 2.0 g of the UV absorber solution according to Example 20 and 10.0 g of silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KR-300) were mixed and stirred for 30 minutes to obtain a light-absorbing composition according to Comparative Example 3. The contents of each component in the UV absorber solution and the light-absorbing composition and the mass ratios of the specified components are shown in Table 4. A coating of the light-absorbing composition was cured on a transparent glass substrate to form a light-absorbing film according to Comparative Example 3 in the same manner as in Example 1, except that the light-absorbing composition according to Comparative Example 3 was used instead of the light-absorbing composition according to Example 1, thereby producing an optical filter according to Comparative Example 3. The transmission spectrum of the optical filter according to Comparative Example 3 is shown in FIG. 25 . The wavelength-transmittance characteristics and the thickness of the light-absorbing film obtained from FIG. 25 are also shown in Table 5.

[0130] Comparative Examples 4 and 5 An ultraviolet absorber solution according to Comparative Example 4 was prepared in the same manner as in Example 1, except that ultraviolet absorber (1-iv) was used instead of ultraviolet absorber (1-i). 2.0 g of the ultraviolet absorber solution according to Comparative Example 4 and 10.0 g of silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KR-300) were mixed and stirred for 30 minutes to obtain a light-absorbing composition according to Comparative Example 4. 2.0 g of the ultraviolet absorber solution according to Comparative Example 4 and 10.0 g of the metal component-containing liquid composition according to Example 1 were mixed and stirred for 30 minutes to obtain a light-absorbing composition according to Comparative Example 5. Except for using the light-absorbing compositions according to Comparative Examples 4 and 5 instead of the light-absorbing composition according to Example 1, coatings of the light-absorbing compositions were cured on transparent glass substrates to form light-absorbing films according to Comparative Examples 4 and 5, respectively, to produce optical filters according to Comparative Examples 4 and 5. The transmission spectra of the optical filters according to Comparative Examples 4 and 5 are shown in FIGS. 26 and 27, respectively. Table 5 shows the wavelength and transmittance characteristics and the thickness of the light absorbing film as seen from FIGS.

[0131] As shown in Table 5, in the optical filters according to Examples 1 to 20, the transmittance T 400 The maximum transmittance T in the wavelength range of 300 to 380 nm was 1% or less, and it was confirmed that the optical filter according to Example 1 had good optical properties including sufficient ultraviolet absorption ability. M 300-380 is 1% or less, and in the optical filters according to the examples other than Examples 12 and 14 to 17, T M 300-380 is 0.5% or less, and in the optical filters according to the examples other than Examples 12 to 17, T M 300-380 In the optical filters according to Examples 1 to 20, the average transmittance T A 550-570 was over 90%.

[0132] The transmission spectrum of the transparent glass substrate used in each example and comparative example is shown in Figure 28. Based on this transmission spectrum, the transmittance T 400 It was suggested that the rate was less than 5%.

[0133] The optical filter according to Example 1 is compared with the optical filter according to Comparative Example 1. In the optical filter according to Comparative Example 1, T 400 was 55.25%. The optical filter according to Example 1 has an increased ability to absorb light at wavelengths around 400 nm and longer than that, compared to the optical filter according to Comparative Example 1. This suggests that the wavelength band of light absorption shifts to the longer wavelength side due to interactions such as partial complex formation between the aluminum component, which is a metal component, and the ultraviolet absorber in the light absorbing film. Also, in the optical filter according to Example 1, the average value T A 550-570 The efficiency was as high as 90% or more. This suggests that the proper inclusion of the ultraviolet absorber in the presence of the alkoxy group suppresses the occurrence of scattering due to the appearance of irregularities on the surface of the light-absorbing film caused by bleed-out.

[0134] The optical filter according to Example 2 is compared with the optical filter according to Comparative Example 2. In the optical filter according to Comparative Example 2, T 400 was 36.39%. The optical filter according to Example 2 has an increased ability to absorb light at wavelengths around 400 nm and longer wavelengths than that, compared to the optical filter according to Comparative Example 2. It is presumed that the same circumstances exist between Example 2 and Comparative Example 2 as between Example 1 and Comparative Example 1.

[0135] In the optical filters according to Examples 1 to 20, the UV cutoff wavelength λ UV is 441 to 480 nm, and in the optical filters according to the examples other than Examples 1 to 4 and 20, the UV cutoff wavelength λ UV was 450 to 480 nm.

[0136] As shown in Table 5, the UV cutoff wavelength λ of the optical filter according to Example 1 UVand the UV cutoff wavelength λ of the optical filter according to Comparative Example 1 UV The difference between the UV cutoff wavelength λ of the optical filter according to Example 2 and the UV cutoff wavelength λ of the optical filter according to Example 2 is 42 nm. UV and the UV cutoff wavelength λ of the optical filter according to Comparative Example 2 UV The difference between the UV cutoff wavelength λ of the optical filter according to Example 20 and the UV cutoff wavelength λ of the optical filter according to Example 20 is 41 nm. UV and the UV cutoff wavelength λ of the optical filter according to Comparative Example 3 UV The difference between the UV cutoff wavelength λ and the UV absorber wavelength λ is 45 nm. From these facts, it can be understood that the UV cutoff wavelength λ of the optical filter according to the present invention is shifted to the longer wavelength side when the light-absorbing film further contains a metal component, compared to when the light-absorbing film contains only the UV absorber. This phenomenon is understood to occur when the light absorption band of the light-absorbing film shifts to the longer wavelength side, or when the absorption maximum wavelength shifts to the longer wavelength side. Such a phenomenon is advantageous from the viewpoint of imparting desired characteristics to the optical filter and improving the characteristics of the optical filter used together with the solid-state imaging device. From the viewpoint of improving the characteristics of the optical filter used together with the solid-state imaging device, the UV cutoff wavelength λ of the optical filter according to the present invention is UV For example, |λ UV -λ UV R | ≧ 10 nm. UV R is the UV cutoff wavelength λ of an optical filter fabricated in the same manner as the optical filter according to the present invention, except that the light-absorbing film does not contain a metal component. UV In the optical filter according to the present invention, it is preferable that |λ UV -λ UV R |≧20 nm or more is satisfied, and more preferably, |λ UV -λ UV R |≧35 nm or more is satisfied, and more preferably, |λ UV -λ UV R |≧40 nm or more is satisfied.

[0137] According to the evaluation results of the optical filters of Comparative Examples 4 and 5, when benzophenone without a hydroxy group in the molecule was used as an ultraviolet absorber, the above-mentioned advantages were not obtained, regardless of the presence or absence of a metal component in the light-absorbing film. Comparing the Examples with Comparative Examples 4 and 5 suggests that in order to shift the UV cutoff wavelength to longer wavelengths, a hydroxy group must be present in one molecule of the ultraviolet absorber, and that an interaction such as complex formation between the hydroxy group or the hydroxy group from which hydrogen has been removed and the metal component is required. Furthermore, in benzophenone-based compounds having a hydroxy group, the mechanism of light absorption is understood to be brought about by a resonance structure involving hydrogen abstraction and acceptance between a carbonyl group and a hydroxy group in one molecule. Examples of substances that absorb light by such hydrogen abstraction and acceptance in one molecule include hydroxybenzophenone, salicylic acid, benzotriazole-based compounds, and triazine compounds. Benzotriazole-based compounds and triazine compounds have a hydroxy group, and a mechanism of hydrogen abstraction and acceptance occurs between the nitrogen in the molecule. On the other hand, in order to cause a shift in the UV cutoff wavelength or a shift in the light absorption band through interaction with a metal component, it is considered desirable to use an ultraviolet absorber having a hydroxy group and a carbonyl group in one molecule, such as hydroxybenzophenone and salicylic acid.

[0138] According to Table 3, the content of the ultraviolet absorber in the light-absorbing composition is, by mass, for example, 0.05% to 3%, preferably 0.1% to 2%, and more preferably 0.2% to 1%. The content of the metal component in the light-absorbing composition is, by mass, for example, 0.005% to 5%, preferably 0.01 to 3%, and more preferably 0.02% to 2%.

[0139] Furthermore, according to Table 3, the content of the ultraviolet absorber in the light-absorbing film 10 is not limited to a specific value. The content is, for example, 0.1% to 10%, preferably 0.2% to 5%, and more preferably 0.4% to 3%, by mass. The content of the metal component in the light-absorbing film 10 is, for example, 0.02% to 5%, preferably 0.04% to 4%, and more preferably 0.06% to 3.5%, by mass.

[0140] Example 21 5.0 g of ultraviolet absorber (1-i), 80.0 g of cyclohexanone, and 8.0 g of polyvinyl butyral were mixed and stirred for 30 minutes. Next, 0.308 g of compound (2-i) containing a metal component was mixed and stirred for 30 minutes, yielding a light-absorbing composition according to Example 21. Details of the light absorber and the metal-component-containing compound are shown in Tables 1 and 2. The content of each component and the mass ratio of the specified components in the light-absorbing composition according to Example 21 are shown in Table 7. Note that the component ratios of the light-absorbing composition according to Example 21 were determined on the assumption that the content of the metal component in compound (2-i) containing a metal component was 6.5 mass % as shown in Table 2.

[0141] The light-absorbing composition according to Example 21 was spin-coated onto one main surface of a transparent glass substrate (manufactured by SCHOTT, product name: D263T eco) made of borosilicate glass and measuring 76 mm x 76 mm x 0.21 mm, to form a coating film. The resulting coating film was thoroughly dried at room temperature and then placed in an oven and heat-treated at 140°C for 1 hour and then at 160°C for 2 hours to complete the reaction, yielding a light-absorbing film according to Example 21. In this manner, an optical filter including the light-absorbing film according to Example 21 was fabricated. The transmission spectra of the optical filter according to Example 21 at incident angles of 0°, 30°, 40°, 50°, 60°, and 70° are shown in FIG. 29 . The reflection spectra of the optical filter according to Example 21 at incident angles of 5°, 40°, 50°, and 60° are shown in FIG. 30 . Table 8 also shows the wavelength and transmittance characteristics observed in FIG. 29 and the thickness of the light-absorbing film. Table 9 shows the incidence angle dependence of the transmission spectrum, |λ 30 UV -λ UV |, |λ 40 UV-λ UV |, |λ 50 UV -λ UV |, |λ 60 UV -λ UV | and |λ 70 UV -λ UV Table 10 shows the maximum reflectance in the wavelength range of 300 nm to 450 nm and the maximum reflectance in the wavelength range of 300 nm to 600 nm for each angle of incidence of the reflection spectrum.

[0142] The optical filter of Example 21 was placed inside a constant temperature and humidity test chamber and subjected to a high temperature and humidity test (dump heat test) in which it was exposed to an environment of a temperature of 85°C and a relative humidity of 85% for 1008 hours. A constant temperature and humidity tester KCL-2000A manufactured by Tokyo Rikakikai Co., Ltd. was used as the constant temperature and humidity test chamber. The optical filter was removed 240 hours and 480 hours after the start of the high temperature and humidity test, and the transmission spectrum of the optical filter was measured. This measurement was performed at 25°C and an incident angle of 0°. Figure 31 shows the transmission spectra of the optical filter of Example 21 before and after the high temperature and humidity test. Table 11 shows |λ DH-240 UV -λ UV The value of | and |T DH-240 480-600 -T m 480-600 The value of |,|λ DH-480 UV -λ UV The value of | and |T DH-480 480-600 -T m 480-600 The value of |,|λ DH-1K UV -λ UV The value of | and |T DH-1K 480-600 -T m 480-600 | indicates the value of

[0143] The optical filter according to Example 21, which had not undergone a high-temperature, high-humidity test, was placed inside a heat cycle chamber and subjected to 1,008 cycles of a heat cycle test at 85°C / -40°C. The temperature inside the heat cycle chamber was maintained at 85°C and -40°C for 30 minutes, respectively, and the temperature was raised or lowered from one temperature to the other over a period of 5 minutes. A thermal shock tester TSA-103ES manufactured by ESPEC Corporation was used as the heat cycle chamber. The optical filter was removed at the end of 144 cycles and 576 cycles, and the transmission spectrum of the optical filter was measured. Figure 32 shows the transmission spectra of the optical filter according to Example 21 before and after the heat cycle test. The measurement was performed at 25°C and an incident angle of 0°. Table 12 shows |λ HC-144 UV -λ UV The value of | and |T HC-144 480-600 -T m 480-600 The value of |,|λ HC-576 UV -λ UV The value of | and |T HC-576 480-600 -T m 480-600 The value of |,|λ HC-1K UV -λ UV The value of | and |T HC-1K 480-600 -T m 480-600 | indicates the value of

[0144] Examples 22 to 35 Optical filters comprising the light-absorbing compositions according to Examples 22 to 35 and the light-absorbing films according to Examples 22 to 35 were produced in the same manner as in Example 21, based on the materials and production conditions shown in Table 1, Table 2 or Table 6, and Table 7. In Examples 26 and 32, a transparent glass substrate that had been coated with a fluorine compound in advance was used, and after the light-absorbing film was formed, the light-absorbing film was peeled off from the transparent glass substrate, thereby obtaining an optical filter comprising the light-absorbing film.

[0145] The transmission spectra of the optical filters according to Examples 22 to 35 were measured at incident angles of 0°, 30°, 40°, 50°, 60°, and 70°. Figures 33 to 36 show the transmission spectra of the optical filters according to Examples 23, 24, 26, and 32. Table 8 shows the parameters that can be seen from the transmission spectra of the optical filters according to Examples 22 to 35 when the incident angle is 0°.

[0146] The reflection spectra of the optical filters according to Examples 22 to 35 were measured at incident angles of 5°, 40°, 50°, and 60°. Figures 37 to 40 show the reflection spectra of the optical filters according to Examples 23, 24, 26, and 32, respectively. Table 10 shows the maximum reflectance in the wavelength range of 300 nm to 450 nm and the maximum reflectance in the wavelength range of 300 nm to 600 nm for each incident angle of the reflection spectra of the optical filters according to Examples 21, 23, 24 to 29, and 32.

[0147] The optical filters of Examples 23, 24, 26, and 32 were subjected to a high temperature and high humidity test and a heat cycle test in the same manner as in Example 21. Tables 11 and 12 show the parameters of the optical filters of Examples 23, 24, 26, and 32, in the same manner as in Example 21.

[0148] Example 36: An optical filter according to Example 36 was obtained by coating both principal surfaces of the optical filter of Example 23 with an antireflection film. The antireflection film included a single layer film containing silicon oxide such as SiO2 formed by a sol-gel method. A liquid antireflection film precursor (alkoxysilane-containing composition) containing at least an alkoxysilane compound and water was prepared. This alkoxysilane-containing composition contained methyltriethoxysilane (MTES) and tetraethoxysilane (TEOS) in a mass ratio of 4:1. Furthermore, this alkoxysilane-containing composition contained water and ethanol as solvents and was prepared by mixing them.

[0149] The alkoxysilane composition was applied to both sides of the optical filter of Example 23 by spin coating. One side of the optical filter was the surface of a light-absorbing film, and the other side of the optical filter was the surface of a transparent glass substrate. In applying the alkoxysilane composition, first, the alkoxysilane composition was applied to one side, and the coating film was temporarily dried by leaving it at room temperature for about 1 minute, and then the alkoxysilane composition was applied to the opposite side. Then, the film was baked at 160°C for about 1 hour to volatilize and remove excess solvent, and the coating film was hardened by hydrolysis and condensation polymerization of the alkoxysilane to obtain an antireflection film. In this way, the optical filter of Example 36 was obtained. The obtained antireflection film was porous and had a thickness of about 180 nm.

[0150] The transmission spectrum of the optical filter according to Example 36 was measured at incident angles of 0°, 30°, 40°, 50°, 60°, and 70°. Figure 41 shows the transmission spectrum of the optical filter according to Example 36. Table 8 shows the parameters that can be seen from the transmission spectrum of the optical filter according to Example 36 when the incident angle is 0°.

[0151] The reflection spectra of the optical filter according to Example 36 were measured at incident angles of 5°, 40°, 50°, and 60°. Figure 42 shows the reflection spectra of the optical filter. Table 10 shows the maximum reflectance in the wavelength range of 300 nm to 450 nm and the maximum reflectance in the wavelength range of 300 nm to 600 nm for each incident angle of the reflection spectrum of the optical filter according to Example 36.

[0152] Examples 37 to 41 Optical filters comprising the light-absorbing compositions of Examples 37 to 41 and the light-absorbing films of Examples 37 to 41 were prepared in the same manner as in Example 21, based on the materials and preparation conditions listed in Tables 1, 2, and 7. For Examples 37 to 41, transmission spectra were measured at incident angles of 0°, 30°, 40°, 50°, 60°, and 70°. Figures 43 and 44 show the transmission spectra of the optical filters of Examples 38 and 41, respectively. Table 8 shows the various parameters that can be observed from the transmission spectra of the optical filters of Examples 37 to 41 when the incident angle is 0°.

[0153] Comparative Example 6 An optical filter including the light-absorbing composition of Comparative Example 6 and the light-absorbing film of Comparative Example 6 was produced in the same manner as in Example 21, based on the materials and production conditions listed in Tables 1, 2, and 7. For Comparative Example 6, the transmission spectrum was measured at incident angles of 0°, 30°, 40°, 50°, 60°, and 70°. Figure 45 shows the transmission spectrum of the optical filter of Comparative Example 6. Table 8 shows each parameter that can be seen from the transmission spectrum of the optical filter of Comparative Example 6 when the incident angle is 0°.

[0154]

[0155]

[0156]

[0157]

[0158]

[0159]

[0160]

[0161]

[0162]

[0163]

Claims

1. an ultraviolet absorber having a hydroxy group and a carbonyl group in the molecule; A metal component-containing compound containing a metal component and an organic oxy group to which at least a portion of the metal component is bonded. Light absorbing composition.

2. 2. The light absorbing composition of claim 1, wherein the hydroxy group and the carbonyl group are spaced apart by 1 to 3 atoms.

3. The light-absorbing composition is capable of forming a light-absorbing film by curing the light-absorbing composition, transmitted light incident on the light absorbing film at an incident angle of 0 degrees has a transmission spectrum in which the transmittance T400 at a wavelength of 400 nm is 5% or less; The light absorbing composition of claim 1 .

4. The light absorbing composition according to claim 1 , wherein the ultraviolet absorber comprises a benzophenone-based compound represented by the following formula (A1): 【Chemistry 1】 [In formula (A1), R 11 , R 12 , R 21 , and R 22 At least one of R is a hydroxy group. 11 , R 12 , R 21 , or R 22 is a functional group other than a hydroxy group, a plurality of R 11 , multiple R 12 , multiple R 21 , or multiple R 22 may be present, R 11 , R 12 , R 21 , and R 22 At least one of may not be present.

5. The light absorbing composition according to claim 1 , wherein the ultraviolet absorber comprises a benzophenone-based compound represented by the following formula (A2): 【Chemistry 2】 [In formula (A2), R 31 is a hydrogen atom, a hydroxyl group, a carboxyl group, an aldehyde group, a halogen atom, a group having a halogen atom, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. 41 and R 42 may be a hydroxy group, a carboxyl group, an aldehyde group, a group having a halogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms; R 41 and R 42 In formula (A2), a plurality of R 41 may be present, and multiple R 42 may also be present.

6. The light absorbing composition according to claim 1 , wherein the ultraviolet absorber comprises a salicylic acid compound represented by the following formula (B): 【Chemistry 3】 [In formula (B), R 51 may be a hydroxy group, a carboxy group, a group containing a halogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. 51 may be present, R 51 In formula (B), R 52 is a hydrogen atom, an aryl group, or a halogenated aryl group in which one or more hydrogen atoms are substituted with halogen atoms.

7. The light-absorbing composition of claim 1, wherein the metal component-containing compound comprises an alkoxide containing the metal component.

8. 2. The light absorbing composition of claim 1 , wherein the metal component comprises at least one selected from the group consisting of Li, Na, Mg, Ca, Sr, Ba, Ge, Sn, Pb, Al, Ga, In, Tl, Zn, Cd, Cu, Ag, Au, Ni, Pd, Pt, Co, Rh, Ir, Fe, Mn, Cr, Mo, W, V, Nb, Ta, Ti, and Zr.

9. 10. The light absorbing composition of claim 1 further comprising a curable resin.

10. 10. The light absorbing composition of claim 9, wherein the resin is a silicone resin.

11. 2. The light absorbing composition according to claim 1, wherein a molar ratio of the content of said ultraviolet absorbing agent to the content of said metal component is 0.001 to 10.

12. an ultraviolet absorber having a hydroxy group and a carbonyl group in the molecule; A metal component-containing compound containing a metal component and an organic oxy group to which at least a portion of the metal component is bonded. Light absorbing film.

13. 13. The light absorbing film according to claim 12, wherein the hydroxy group and the carbonyl group are spaced apart by 1 to 3 atoms.

14. The transmitted light incident on the light absorbing film at an incident angle of 0 degrees has a transmission spectrum in which the transmittance T400 at a wavelength of 400 nm is 5% or less. The light absorbing film according to claim 12.

15. The light-absorbing film according to claim 12 , wherein the ultraviolet absorber comprises a benzophenone-based compound represented by the following formula (A1): 【Chemistry 4】 [In formula (A1), R 11 , R 12 , R 21 , and R 22 At least one of R is a hydroxy group. 11 , R 12 , R 21 , or R 22 is a functional group other than a hydroxy group, a plurality of R 11 , multiple R 12 , multiple R 21 , or multiple R 22 may be present, R 11 , R 12 , R 21 , and R 22 At least one of may not be present.

16. The light-absorbing film according to claim 12 , wherein the ultraviolet absorber comprises a benzophenone-based compound represented by the following formula (A2): 【Chemistry 5】 [In formula (A2), R 31 is a hydrogen atom, a hydroxyl group, a carboxyl group, an aldehyde group, a halogen atom, a group having a halogen atom, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. 41 and R 42 may be a hydroxy group, a carboxyl group, an aldehyde group, a group having a halogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms; R 41 and R 42 In formula (A2), a plurality of R 41 may be present, and multiple R 42 may also be present.

17. The light-absorbing film according to claim 12 , wherein the ultraviolet absorber comprises a salicylic acid compound represented by the following formula (B): 【Chemistry 5】 [In formula (B), R 51 may be a hydroxy group, a carboxy group, a group containing a halogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. 51 may be present, R 51 In formula (B), R 52 is a hydrogen atom, an aryl group, or a halogenated aryl group in which one or more hydrogen atoms are substituted with halogen atoms.

18. The light absorbing film of claim 12, wherein the metal component-containing compound includes an alkoxide containing the metal component.

19. 13. The light absorbing film according to claim 12, wherein the metal component comprises at least one selected from the group consisting of Li, Na, Mg, Ca, Sr, Ba, Ge, Sn, Pb, Al, Ga, In, Tl, Zn, Cd, Cu, Ag, Au, Ni, Pd, Pt, Co, Rh, Ir, Fe, Mn, Cr, Mo, W, V, Nb, Ta, Ti, and Zr.

20. The light-absorbing film according to claim 12 , further comprising a silicone resin.

21. Applying a light absorbing composition according to any one of claims 1 to 11 onto a substrate; and heating the light absorbing composition at a temperature of 120° C. or higher. A method for producing a light absorbing film.

22. An optical filter comprising the light absorbing film according to any one of claims 12 to 20.

23. The transmitted light incident on the optical filter at an incident angle of 0 degrees has a transmission spectrum in which the maximum transmittance T M 300-380 in the wavelength range of 300 to 380 nm is 3% or less.

23. The optical filter of claim 22.

24. The optical filter of claim 23, wherein the transmission spectrum has a transmittance of 50% and includes an ultraviolet cutoff wavelength λ UV in the range of 405 nm to 500 nm.

25. The optical filter according to claim 23, wherein the transmission spectrum has an average transmittance T A 550-570 of 87% or more in the wavelength range of 550 to 570 nm.

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