Light-absorbing compositions, light-absorbing films, and optical filters

Abstract

The present invention provides a light-absorbing composition, a light-absorbing film, and an optical filter that are advantageous in terms of reproducing human visual sensitivity, particularly in terms of light absorption characteristics in the short-wavelength region, as well as a method for manufacturing such a light-absorbing film. [Solution] The light-absorbing composition according to the present invention contains an ultraviolet absorber having a hydroxyl group and a carbonyl group in its molecule, and a metal component. At least a portion of the metal component is bonded to an organic oxy group.

Description

[Technical Field]

[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. [Background technology]

[0002] In imaging devices using solid-state image sensors such as CCDs (Charge Coupled Devices) or CMOSs ​​(Complementary Metal Oxide Semiconductors), various optical filters are placed in front of the solid-state image sensor to obtain images with good color reproduction. Generally, solid-state image sensors have spectral sensitivity over a wider wavelength range than the human visual sensitivity corresponding to the visible light region. For this reason, a technique is known in which an optical filter that blocks some infrared or ultraviolet light is placed in front of the solid-state image sensor to bring the spectral sensitivity of the solid-state image sensor in the imaging device closer to the human visual sensitivity.

[0003] Traditionally, optical filters typically used dielectric multilayer films to block infrared or ultraviolet light through light reflection. However, in recent years, optical filters equipped with films containing light-absorbing agents have attracted attention. Because the transmittance characteristics of optical filters with films containing light-absorbing agents are less affected by the angle of incidence, good images with minimal color changes can be obtained even when light is incident on the optical filter at an oblique angle in the imaging device. Furthermore, light-absorbing optical filters that do not use light-reflective films can suppress the occurrence of ghosting and flare caused by multiple reflections by light-reflective films, making it easier to obtain good images in backlit conditions and when shooting night scenes. In addition, optical filters with films containing light-absorbing agents are also advantageous in terms of miniaturization and thinning of imaging devices.

[0004] As such light absorbers, those formed from phosphonic acid and copper ions are known. For example, Patent Document 1 describes an optical filter comprising 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 equipped with a UV-IR absorbing layer capable of absorbing infrared and ultraviolet rays. The UV-IR absorbing layer contains a UV-IR absorbent formed from phosphonic acid and copper ions. To ensure that the optical filter satisfies predetermined optical properties, the UV-IR absorbing composition contains, for example, phenyl phosphonic acid and phosphonic acid having an alkyl group or a halogenated alkyl group (alkyl phosphonic acid).

[0006] Furthermore, Patent Document 3 describes an ophthalmic device that includes a violet light vertical cutoff filter. The violet light vertical cutoff filter abruptly absorbs light with wavelengths in the range of approximately 400 nm to 450 nm. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] International Publication No. 2018 / 088561 [Patent Document 2] Patent No. 6232161 [Patent Document 3] Special Publication No. 2007-535708 [Overview of the project] [Problems that the invention aims to solve]

[0008] The technologies described in Patent Documents 1 and 2 warrant reconsideration from the viewpoint 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 considered to have low transmittance of visible light around 500-650 nm. Therefore, the present invention provides a light-absorbing composition, a light-absorbing film, and an optical filter that are advantageous from the viewpoint of reproducing human visual sensitivity, particularly in terms of light absorption characteristics in the short-wavelength region. The present invention also provides a method for manufacturing such a light-absorbing film. [Means for solving the problem]

[0009] The present invention UV absorbers having hydroxyl groups and carbonyl groups in their molecules, It contains metal components, At least a portion of the aforementioned metal component is bonded to an organic oxy group. A light-absorbing composition is provided.

[0010] Furthermore, the present invention is UV absorbers having hydroxyl groups and carbonyl groups in their molecules, It contains metal components, At least a portion of the aforementioned metal component is bonded to an organic oxy group. We provide a light-absorbing film.

[0011] Furthermore, the present invention is The above light-absorbing composition is cured by heating it at a temperature of 120°C or higher. This invention provides a method for manufacturing a light-absorbing film.

[0012] Furthermore, the present invention provides an optical filter equipped with the above-described light-absorbing film. [Effects of the Invention]

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

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

[0015] In optical filters for imaging devices using solid-state image sensors, if effective absorption of light in the short-wavelength region around 400 nm can be achieved, the value of the optical filter can be further enhanced from the viewpoint 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 350 nm to 450 nm range 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 350 nm to 450 nm range 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 from the viewpoint 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 visible light around 500 to 650 nm of that filter is considered to be low.

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

[0017] The following describes embodiments of the present invention. Note that the following description is illustrative and not limited to the embodiments described below.

[0018] The light-absorbing composition according to the present invention contains an ultraviolet absorber having hydroxyl and carbonyl groups in its molecule, and a metal component. In addition, 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 the oxygen atom in the organic oxy group. As a result, a light-absorbing film or optical filter made using the light-absorbing composition is more likely to effectively absorb light in the wavelength region around 400 nm, which is advantageous from the viewpoint of reproducing human visual sensitivity.

[0019] Advantageous conditions for UV absorbers include appropriate light absorption and transmission ranges, photochemical stability, low photosensitization effect that does not affect the range of use, and thermochemical stability. From this perspective, it is conceivable that the mechanism of light absorption by UV absorbers utilizes the intramolecular hydrogen transfer reaction of hydroxyl groups (intramolecular hydrogen abstraction reaction) induced by photoexcitation. Examples of UV absorbers that exhibit such a mechanism include compounds such as hydroxybenzophenone, salicylic acid, hydroxyphenylbenzotriazole, hydroxyphenyltriazine, and substituted acrylonitrile. In hydroxybenzophenone and salicylic acid, the reaction involving the transfer of hydrogen between the hydroxyl group and carbonyl group within the molecule is involved in the absorption of ultraviolet light and other light. On the other hand, in hydroxyphenylbenzotriazole, hydroxyphenyltriazine, and substituted acrylonitrile, the reaction involving the transfer of hydrogen between the hydroxyl group and nitrogen atom within the molecule is involved in the absorption of ultraviolet light and other light. These UV absorbers have hydroxyl groups with lone pairs of electrons within their molecules, and it is presumed that they interact with coexisting metal components or hydrogen donors, such as through partial complexation. We compared the case where a UV absorber with hydroxyl groups exists alone with the case where a metal component or hydrogen donor and a UV absorber with hydroxyl groups coexist in a system of light-absorbing compositions and their cured products. This comparison revealed differences in optical properties, such as their light absorption spectra and light transmission spectra, supporting the above presumption. In particular, it was found that in a light-absorbing film obtained by curing a light-absorbing composition containing UV absorbers with hydroxyl and carbonyl groups within their molecules, along with a metal component, the light absorption band at wavelengths of 300-500 nm shifts to longer wavelengths. Therefore, such a light-absorbing film is advantageous for effectively and appropriately absorbing light around 400 nm. Furthermore, if the light absorption band shifts to longer wavelengths, phenomena such as the maximum absorption wavelength shifting to longer wavelengths within the 300nm to 500nm range of the transmission spectrum, or the wavelength at which transmittance is 50% (UV cutoff wavelength) shifting to longer wavelengths, may become apparent.Thus, according to the light-absorbing composition, the light-absorbing film which is a cured product thereof, and the optical filter equipped with the light-absorbing film, the absorption characteristics inherent in the ultraviolet absorber are adjusted to effectively absorb light in the short-wavelength region. As a result, the spectral transmittance of such a light-absorbing film or optical filter tends to be more suitable when used with a solid-state image sensor 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 MOR state. R represents a predetermined organic group, such as an alkyl group, an aryl group, or a vinyl group.

[0021] The arrangement of hydroxyl groups and carbonyl groups in UV absorbers is not limited to a specific configuration. Preferably, in UV absorbers, the hydroxyl group and the carbonyl group are separated by 1 to 3 atoms. This is thought to facilitate hydrogen transfer between the hydroxyl group and the carbonyl group in the UV absorber. As a result, the phenomenon of the light absorption band shifting to longer wavelengths in the 300-500 nm range is effectively facilitated. Consequently, the light-absorbing film obtained by curing the light-absorbing composition is more reliably able to effectively and appropriately absorb light around 400 nm.

[0022] In the transmission spectrum of a 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 at a wavelength of 400 nm is... 400 For example, this is 10% or less. As a result, the light-absorbing film obtained by curing the light-absorbing composition is more reliably able to effectively and appropriately absorb light around a wavelength of 400 nm.

[0023] Transmittance T 400 The percentage 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 is not easily aggregated even when mixed with a metal component.

[0025] The ultraviolet absorber preferably contains a benzophenone compound represented by the following formula (A1). In this case, the light absorption film or optical filter produced using the light absorption composition can more reliably and effectively absorb light in the short wavelength region near 400 nm.

[0026]

Chemical formula

[0027] In formula (A1), at least one of R 11 , R​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​

[0029] The ultraviolet absorber more preferably includes a benzophenone compound represented by the following formula (A2). In this case, the light-absorbing film or optical filter made using the light-absorbing composition is more reliably able to effectively absorb light in the short-wavelength region around 400 nm.

[0030] [ka]

[0031] In equation (A2), R 31 R 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. In formula (A2), R 41 and R 42 R may be a hydroxyl 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. 41 and R 42 It does not have to exist. In equation (A2), multiple R 41 There may be multiple R 42 A halogen atom may be present. The group having a halogen atom may be an alkyl halide 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 an aryl halide 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 an alkoxy halide 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. The benzophenone compound is, for example, 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 compound represented by the following formula (B). In this case, the light-absorbing film or optical filter made using the light-absorbing composition is more reliably and effectively absorbs light in the short-wavelength region around 400 nm.

[0034] [ka]

[0035] In equation (B), R 51 R may be a hydroxyl group, a carboxyl 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. In formula (B), multiple R 51 It is possible for R to exist, 51 It is not necessary for R to exist. In equation (B), 52This is a hydrogen atom, an aryl group, or an aryl halide in which one or more hydrogen atoms are substituted with halogen atoms. The group having a halogen atom may be an alkyl halide 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 an aryl halide 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 an alkoxy halide in which at least one hydrogen atom in the alkoxy group is substituted with a halogen atom.

[0036] The salicylic acid compounds represented by formula (B) are not limited to specific compounds. For example, the salicylic acid compounds represented by formula (B) include at least one selected from the group consisting of phenyl salicylate, 4-butylphenyl salicylate, and octylphenyl salicylate.

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

[0038] The light-absorbing composition may contain a predetermined compound containing a metal component. This compound is, for example, a complex. Preferably, the light-absorbing composition contains an alkoxide containing a metal component.

[0039] The metallic component includes, for example, 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. In this case, the metallic component readily interacts with the above-mentioned 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% by mass, preferably 0.1 to 8%, and more preferably 0.2 to 6%. The content may also be 3% or less, 2% or less, or 1% or less.

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

[0042] In a 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. The ratio, on a mass basis, is, for example, 0.05 to 300, preferably 0.07 to 280, and more preferably 0.1 to 260. The 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. The molar ratio is, for example, 0.001 to 40, preferably 0.005 to 35, and more preferably 0.01 to 30. The molar ratio may be 25 or less, 20 or less, 15 or less, 10 or less, 5 or less, or 3 or less. As a result, light-absorbing films or optical filters made using light-absorbing compositions are more reliably and effectively able to 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 coating the light-absorbing composition onto a predetermined substrate and curing the resin, an article with a substrate having desired light-absorbing properties can be produced.

[0044] Curable resins are not limited to specific resins. Examples of curable resins include acrylic resins, epoxy resins, polycarbonate resins, polyether resins, polyester resins, cyclic olefin resins, silicone resins, or polyvinyl acetal (PVA) resins.

[0045] The resin is preferably a silicone resin. More preferably, the resin is a silicone resin containing aryl groups such as phenyl groups. If the resin contained in the light-absorbing film is hard (rigid), cracks are likely to occur due to curing shrinkage during the fabrication of the light-absorbing film as the thickness of the layer containing the resin increases. If the resin is a silicone resin containing aryl groups, the light-absorbing film formed by the light-absorbing composition tends to have good crack resistance. In addition, silicone resins containing aryl groups tend to have high compatibility or dispersibility with metal components and ultraviolet absorbers, and are less likely to aggregate 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. Because the light-absorbing composition contains silicone resin, the light-absorbing film obtained using the light-absorbing composition is also expected to contain silicone resin and have heat resistance. From this viewpoint, it is advantageous for the light-absorbing composition to contain silicone resin as a curable resin.

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

[0047] The resin may preferably be a PVA resin. More preferably, the PVA resin is 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 and PVF resins contain acetyl and hydroxyl groups bonded to vinyl groups, in addition to butyral or formal groups. These resins may have the advantage of good affinity with metal components due to the contribution of some of the hydroxyl groups they contain. PVB and PVF resins can contain relatively large amounts of UV absorbers, and the cured resin composition tends to have high flexibility and durability.

[0048] Specific examples of PVB resins are Esrec 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 Esrec is a registered trademark. Another specific example of PVB resin is 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. Because the light-absorbing composition contains PVA resin, the light-absorbing film obtained using the light-absorbing composition also contains PVA resin and tends to have flexibility and durability. In particular, PVB resin has a proven track record of use as an interlayer in automobile windshields, and high transparency and non-yellowing properties can be expected.

[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 appropriate amounts 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; and (VI) glycol ether-based organic solvents such as propylene glycol monomethyl ether and dipropylene glycol methyl ether. These organic solvents may be used individually or in combination of two or more. In particular, because of its excellent transparency and the stability of the resin solution over time, the organic solvent is preferably an aromatic organic solvent, an alcohol-based organic solvent, or a mixture thereof, and more preferably a mixture of an aromatic organic solvent and an alcohol-based organic solvent. In this case, the aromatic organic solvent is preferably toluene, and the alcohol-based organic solvent is preferably ethanol or propanol, and more preferably ethanol. Furthermore, when using a mixture of an aromatic organic solvent and an alcohol-based organic solvent as the organic solvent, it is preferable to use it under the condition that the mass of the aromatic organic solvent : the mass of the alcohol-based organic solvent = 1:0.1 to 10, and more preferably under the condition that the mass of the aromatic organic solvent : the mass of the alcohol-based organic solvent = 1:0.5 to 5. From the viewpoint of solubility in various solvents, PVB resin is preferably used.

[0050] Including a UV absorber having hydroxyl and carbonyl groups in its molecule, a metal component, and a PVA resin in a light-absorbing composition is advantageous from the viewpoint of suppressing the bleed-out of the UV absorber. When an additive-type UV absorber is included in the PVB resin, depending on the usage environment and the conditions of the light-absorbing film manufacturing method, the UV absorber may powderize or float to the surface of the light-absorbing film or optical film. When a light-absorbing composition or light-absorbing film contains a UV absorber having hydroxyl and carbonyl groups in its molecule, a metal component, and a PVA resin, the UV absorber, which is partially complexed with the metal component, becomes more likely to bond with some of the hydroxyl groups of the PVA resin via the metal component. As a result, the UV absorber is relatively strongly retained inside the resin matrix, and the bleed-out of the UV absorber is easily suppressed.

[0051] An example of a method for preparing a light-absorbing composition is described below. 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 a metal component. A light-absorbing composition can be prepared by mixing the solution of the ultraviolet absorber and the liquid composition containing a metal component in predetermined amounts and stirring.

[0052] The light-absorbing composition may be a liquid composition containing PVB resin. This liquid composition usually 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 to dissolve PVB, an organic solvent may be used, taking into account the solubility of PVB. The concentration of PVB in the liquid composition is not limited to a specific value. It is set appropriately considering the solubility of PVB in the solvent. The concentration is, for example, about 10 to 50% by mass.

[0053] A light-absorbing film 10, as shown in Figure 1, can be provided using a light-absorbing composition. 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 an ultraviolet absorber having hydroxyl and carbonyl groups 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 the oxygen atom in the organic oxy group. As a result, the light-absorbing film 10 is able 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 MOR state. R represents a predetermined 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, preferably, the hydroxyl group and the carbonyl group are separated by 1 to 3 atoms. This makes it easier for the light-absorbing film 10 to reliably, effectively, and appropriately absorb light around a wavelength of 400 nm.

[0056] The ultraviolet absorber in the light-absorbing film 10 includes, for example, a benzophenone compound represented by the above formula (A1). This makes the light-absorbing film 10 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 compound represented by the above formula (A2). This makes the light-absorbing film 10 more reliably able to effectively absorb light in the short-wavelength region around 400 nm.

[0058] The ultraviolet absorber in the light-absorbing film 10 includes, for example, a salicylic acid-based compound represented by formula (B) above. This makes the light-absorbing film 10 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, for example, 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.

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

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

[0063] The thickness of the light-absorbing film 10 is not limited to a specific value. For example, the thickness of the light-absorbing film 10 may be 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 at a wavelength of 400 nm is shown. 400 For example, it is 5% or less.

[0065] In the manufacture 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 can 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 150-160°C. This makes it easier for the light-absorbing film 10 to have good heat resistance while preventing degradation of the ultraviolet absorber.

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

[0067] As shown in Figures 1 and 2, for example, optical filters 1a and 1b equipped with a light-absorbing film 10 can be provided. Optical filters 1a and 1b can effectively absorb light in the short-wavelength region around 400 nm.

[0068] In the transmission spectra of optical filters 1a and 1b at an incident angle of 0 degrees, the maximum value T of transmittance in the wavelength range of 300 to 380 nm is... M 300-380 For example, this is less than 3%. This allows the optical filter to effectively absorb light in the short-wavelength region around 400 nm.

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

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

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

[0072] In the transmission spectra of optical filters 1a and 1b at an incident angle of 0 degrees, the average value T of transmittance in the wavelength range of 550 to 570 nm is... A 550-570 For example, this is 87% or more. As a result, optical filters 1a and 1b can transmit visible light appropriately, which is advantageous from the standpoint of reproducing human visual sensitivity.

[0073] Average value of transmittance T A 550-570 The percentage should preferably be 88% or higher, and more preferably 90% or higher.

[0074] The transmission spectra obtained by incidenting light in the wavelength range of 300 nm to 1200 nm onto optical filters 1a and 1b at an incident angle of 0° may satisfy the requirements of (ia), (ii-a), (iii-a), (iv-a), (va), and (vi-a) below. (ia) Maximum transmittance T in the wavelength range of 300 nm to 380 nm M 300-380 The percentage is less than 3%. (ii-a) Transmittance T at a wavelength of 400 nm 400 It is less than 5%. (iii-a) Transmittance T at a wavelength of 410 nm 410 It is less than 10%. (iv-a) The wavelength λ in the range of 350 nm to 500 nm at which the transmittance is 50% UV [nm] is within the range of 405nm to 490nm. (va) Average value T of transmittance at wavelengths of 550nm to 570nm A 550-570 The percentage is over 87%. (vi-a) Wavelength (λ UV Transmittance T at -10 nm 0 UV-Wavelength (λ) UV Transmittance T at +10 nm 0 UV+ Ratio T 0 UV+ / T 0 UV- The value is 1.8 or higher.

[0075] By satisfying the requirements of (ia) above, optical filters 1a and 1b can exhibit high ultraviolet absorption. Maximum value T M 300-380 It 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] In addition to the requirements of (ia), optical filters 1a and 1b can exhibit higher ultraviolet absorption by satisfying the requirements of (ii-a) and (iii-a) above. In particular, optical filters 1a and 1b can be used for optical filter applications that require higher ultraviolet absorption performance. Transmittance T 400 The transmittance T is preferably 4% or less, more preferably 3% or less, and even more preferably 1% or less. 410 The percentage 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 requirements of (iv-a) above, optical filters 1a and 1b can exhibit high ultraviolet absorption, and the spectrum perceived by the image sensor will more easily match the spectrum corresponding to human visual sensitivity. Wavelength λ UV The wavelength range is preferably 420nm to 490nm, and more preferably 420nm to 450nm. In this case, purple fringing is easily suppressed in the resulting image. Purple fringing is a chromatic aberration that appears particularly around the contours of the subject, exhibiting a slightly purple hue. In addition, the transmittance of light belonging to 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 belonging to the human visible light range tends to be higher, making it easier to obtain brighter images. In particular, the transmittance in the wavelength range corresponding to the maximum sensitivity on the human luminous efficiency curve tends to be higher, making it easier for humans to perceive brightness when observing the image. Average value T A 550-570 The percentage should preferably be 88% or higher, and more preferably 90% or higher.

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

[0080] The reflection spectra obtained by incidenting light in the wavelength range of 300 nm to 1200 nm onto optical filters 1a and 1b at an incident angle of 5° may satisfy the requirements of (ib) and (ii-b) below. In addition, the reflection spectra obtained by incidenting light in the wavelength range of 300 nm to 1200 nm onto optical filters 1a and 1b at an incident angle of 40° may satisfy the requirements of (iii-b) and (iv-b) below. Furthermore, the reflection spectra obtained by incidenting light in the wavelength range of 300 nm to 1200 nm onto optical filters 1a and 1b at an incident angle of 60° may satisfy the requirements of (vb) and (vi-b) below. (ib) Maximum reflectance R in the wavelength range of 300 nm to 450 nm 5 300-450 The percentage is less than 20%. (ii-b) Maximum reflectance R in the wavelength range of 300 nm to 600 nm 5 300-600 The percentage is 25% or less. (iii-b) The maximum value R of the reflectance in the wavelength range of 300 nm to 450 nm 40 300-450 is 20% or less. (iv-b) The maximum value R of the reflectance in the wavelength range of 300 nm to 600 nm 40 300-600 is 25% or less. (v-b) The maximum value R of the reflectance in the wavelength range of 300 nm to 450 nm 60 300-450 is 30% or less. (vi-b) The maximum value R of the reflectance in the wavelength range of 300 nm to 600 nm 60 300-600 is 35% or less.

[0081] Meeting the requirements of (i-b) to (vi-b) above is very advantageous from the perspective of preventing ghost, flare, or noise generated by multiple scattering of the reflected light reflected from the surfaces of the optical filters 1a and 1b, for example, inside or at the edges of the camera module or the housing. The maximum value R 5 300-450 is preferably 15% or less. The maximum value R 40 300-450 is preferably 15% or less. The maximum value R 60 300-450 is preferably 20% or less. The maximum value R 5 300-600 is preferably 20% or less. The maximum value R 40 300-600 is preferably 20% or less. The maximum value R 60 300-600 is preferably 25% or less.

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

[0083] A fully absorbent UV-cut filter has the advantage of having little angle dependence of the transmission spectrum. UV-cut filters that cut UV rays with a reflective film tend to shift the UV cutoff wavelength to the shorter wavelength side for light incident at an oblique angle. Therefore, the UV rays that you want to cut may be detected by the sensor depending on the angle of incidence. On the other hand, optical filters 1a and 1b satisfy the above requirements (ic) to (vc), and the change in UV cutoff wavelength for oblique incidence is small, and the shift of the UV cutoff wavelength to the shorter wavelength side is less likely to occur. Therefore, with optical filters 1a and 1b, in addition to the function of suppressing ghosting and flare, it is easier to achieve good color reproduction with less color unevenness in the plane, and high-quality images can be easily obtained.

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

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

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

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

[0088] If optical filters 1a and 1b satisfy requirements (ie), (ii-e), and (iii-e), then even if the ambient temperature of optical filters 1a and 1b changes, optical filters 1a and 1b will be able to exhibit high ultraviolet absorption, and the spectrum perceived by the image sensor will more easily match the spectrum corresponding to human visual sensitivity. In addition, even if the ambient temperature of optical filters 1a and 1b changes, the transmittance of light belonging to the human visible light range will tend to increase, making it easier to obtain bright images.

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

[0090] The optical filter 1a can be manufactured, for example, by peeling off a light-absorbing film 10 formed on a substrate. In this case, the substrate material may be glass, resin, or metal. The surface of the substrate may be subjected to a surface treatment such as a coating using a fluorine-containing compound.

[0091] As shown in Figure 2A, the optical filter 1b comprises 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, for example, be in contact with one main surface of the transparent dielectric substrate 20. In this case, for example, the light-absorbing film 10 can be formed 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 absorbing ability in the infrared region. The transparent dielectric substrate 20 may have an average spectral transmittance of 90% or more at wavelengths of, for example, 350 nm to 900 nm. The material of the transparent dielectric substrate 20 is not limited to a specific material, but may be, for example, a predetermined glass or resin. When the material of the transparent dielectric substrate 20 is glass, the transparent dielectric substrate 20 may be, for example, a transparent glass made of silicate glass such as soda-lime glass and borosilicate glass, or a phosphate glass and fluorine phosphate glass containing coloring components such as Cu and Co. Phosphate glass and fluorine phosphate glass containing coloring components are, for example, infrared absorbing glasses and have light absorbing properties themselves. When the light absorbing film 10 is used together with the infrared absorbing glass transparent dielectric substrate 20, the light absorption and transmission spectra of both can be adjusted to fabricate an optical filter with desired optical properties, providing a high degree of freedom in the design of the optical filter.

[0093] If the material of the transparent dielectric substrate 20 is a resin, the resin may be, for example, a cyclic olefin resin such as 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 further modified to include other functional films such as an infrared absorbing film, an infrared reflective film, and an anti-reflective film. Such functional films may be provided on the light absorbing film 10 or the transparent dielectric substrate 20. For example, by including an anti-reflective film in the optical filter, the transmittance in a predetermined wavelength range (e.g., the visible light range) can be increased. The anti-reflective film may be composed of layers of low refractive index materials such as MgF2 and SiO2, a laminate of such low refractive index material layers and layers of high refractive index materials such as TiO2, or a dielectric multilayer film. Such anti-reflective 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 methods.

[0095] The optical filter may be constructed, for example, by placing a light-absorbing film 10 between two plate-shaped 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 scratch prevention, etc. These advantages are particularly important when a relatively flexible resin is used as the binder or matrix in the light-absorbing film 10.

[0096] By curing a light-absorbing composition and providing an anti-reflective coating on the surface of the light-absorbing film and the optical filter, an optical filter with even better optical properties can be provided. For example, as shown in Figure 2B, an optical filter 1c equipped with a light-absorbing film 10 and an anti-reflective coating 30 can be provided. In an optical filter with an anti-reflective coating, when light is incident on the optical filter at a predetermined incident angle, the light reflected from the optical filter is reduced to almost zero. This is very advantageous in imaging devices equipped with an optical filter with an anti-reflective coating, for example, from the viewpoint of preventing ghosting, flare, and noise caused by multiple scattering of reflected light within the imaging device or camera module.

[0097] The material of the anti-reflective coating is not limited to a specific material. The method of forming the anti-reflective coating is not limited to a specific method. The method of forming the anti-reflective coating may be a gas-phase method or a liquid-phase method. For example, the method of forming the anti-reflective coating may be a vapor deposition method. The method of forming the anti-reflective coating may also be a sol-gel method using a silicon-containing reactive material, and this method is an excellent liquid-phase method for forming anti-reflective coatings.

[0098] Anti-reflective coatings can be single-layer films composed of the same type of material, or multilayer films composed of two or more different materials. The materials constituting each layer of the film and multilayer film are not limited to specific materials. These materials include, for example, inorganic compounds such as SiO2, TiO2, Ta2O3, MgF2, Al2O3, CaF2, ZrO2, CeO2, and ZnS. For example, if an anti-reflective coating or a layer contained within an anti-reflective coating contains SiO2, the coating or layer may be formed by the so-called sol-gel method using an alkoxysilane compound as a starting material. In the sol-gel method, the alkoxysilane compound undergoes hydrolysis and condensation polymerization in the presence of water and a catalyst to obtain a dense and 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 film using the sol-gel method, the starting material is not limited to a specific material, nor are the functional groups it possesses limited to a specific functional group. Preferably, the starting material 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 films or layers with a strong and dense framework. On the other hand, with tetrafunctional silanes alone, it is difficult to control the reactivity and adjust the polarization 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 framework is improved, making it easier to adjust the polarization of the film or layer and suppressing cracks in the film or layer. Easier adjustment of the polarization of the film or layer is desirable from the viewpoint of adjusting the refractive index of the anti-reflective film. The organic functional groups in trifunctional silanes are not inherently limited to a specific functional group. In particular, trifunctional silanes having a methyl group as an organic functional group are desirable in order to form a homogeneous liquid and coating film when combined with tetrafunctional silanes.

[0100] In the starting material, the ratio of the amount of "trifunctional silane containing alkyl groups" to the amount of "tetrafunctional silane" is not limited to a specific value. Preferably, in the starting material, the relationship between the amount of "trifunctional silane containing alkyl groups" and the amount of "tetrafunctional silane" by mass is satisfied to 5:1 to 1:3. This makes it easier to suppress cracks in the anti-reflective coating and to form a strong framework with the tetrafunctional silane. The starting material may contain components other than those involved in the sol-gel method. For example, the starting material may contain fine particles and fillers to adjust the refractive index. In this case, the fine particles and fillers may be hollow and may be high refractive index materials. The starting material may contain components that decompose at low temperatures. This makes it easier to adjust the refractive index of the anti-reflective coating. In the sol-gel method, the temperature at which the coating is fired 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 optical filter can have high heat resistance, problems do not occur during the firing of the coating film in the sol-gel method, and a strong anti-reflective film can be easily formed.

[0101] When the anti-reflective coating is a single layer, it is desirable that the refractive index of the single layer material be low. The reflectivity is most likely to be small when the refractive index n1 of the anti-reflective coating material is n1 = √n0. n0 is the refractive index of the substrate for forming the anti-reflective coating. For example, when the anti-reflective 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 with a refractive index of approximately 1, so the refractive index of the anti-reflective coating tends to be low. If the refractive index required for the anti-reflective coating is not so low, the anti-reflective coating may contain solid particles formed from the above materials. When mechanical strength such as scratch resistance is required for the anti-reflective coating, it is advantageous for the anti-reflective coating to contain such solid particles. Film formation may be performed by the sol-gel method with such hollow particles or solid particles included. In particular, when hollow or solid particles made of SiO2 are used, the affinity between the SiO2 in the film formed by the sol-gel method and the hollow or solid particles is good, which suppresses aggregation of the hollow or solid particles and can be expected to suppress bleed-out.

[0102] The anti-reflective coating may have a multilayer structure comprising a layer containing SiO2 formed by the sol-gel method and a layer formed by, for example, vacuum deposition, the sol-gel method, or other methods. For example, by forming a multilayer anti-reflective coating with two or more materials having different refractive indices, a relatively wide wavelength band in which the anti-reflective effect is obtained can be secured, and the minimum reflectance in the optical filter tends to be lower. When a multilayer structure is formed in the anti-reflective coating by combining it with a layer containing SiO2 formed by the sol-gel method, the combined layer may be, for example, a layer containing hollow particles and SiO2 formed by the sol-gel method, a layer made of a material having a relatively high refractive index such as TiO2 and Ta2O3, or a layer made of other materials such as MgF2.

[0103] As shown in Figure 2B, for example, in the optical filter 1c, the incident and exit surfaces of light are formed by an anti-reflective coating 30. In other words, the optical filter 1c has, for example, an anti-reflective coating 30 on both sides. The anti-reflective coating 30 contains, for example, SiO2. When light in the wavelength range of 300 nm to 1200 nm is incident on the optical filter 1c at an incident angle of 0°, the transmission spectrum obtained 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 300nm to 380nm M 300-380 The percentage is less than 0.1%. (ii-f) Transmittance Tb at a wavelength of 400 nm 400 It is less than 5%. (iii-f) Transmittance Tb at a wavelength of 410 nm 410 It is less than 10%. (iv-f) Wavelength λb at which transmittance is 50% within the wavelength range of 350nm to 500nm UV [nm] is within the range of 405nm to 490nm. (vf) Minimum transmittance Tb at wavelengths of 480nm to 600nm m 480-600 The percentage is over 92%. (vi-f) Average value Tb of transmittance at wavelengths of 550nm to 570nm a 550-570 It is over 90%. (vii-f) Wavelength (λb UV Transmittance Tb at -10 nm 0 UV- For the wavelength (λb UV Transmittance Tb at +10 nm 0 UV+ ratio Tb 0 UV+ / Tb 0 UV- The value is 2.5 or higher.

[0104] The reflection spectrum obtained by incidenting light in the wavelength range of 300 nm to 1200 nm onto the optical filter 1c at an incident angle of 5° satisfies, for example, the requirements of (ig) and (ii-g) below. The reflection spectrum obtained by incidenting light in the wavelength range of 300 nm to 1200 nm onto the optical filter 1c at an incident angle of 40° satisfies, for example, the requirements of (iii-g) and (iv-g) below. The reflection spectrum obtained by incidenting light in the wavelength range of 300 nm to 1200 nm onto the optical filter 1c at an incident angle of 60° satisfies, for example, the requirements of (vg) and (vi-g) below. (ig) Maximum reflectance R in the wavelength range of 300 nm to 450 nm 5 300-450 The percentage is 7% or less. (ii-g) Maximum reflectance R in the wavelength range of 300 nm to 600 nm 5 300-600 The percentage is 9% or less. (iii-g) Maximum reflectance R in the wavelength range of 300 nm to 450 nm 40 300-450 The percentage is 8% or less. (iv-g) Maximum reflectance R in the wavelength range of 300 nm to 600 nm 40 300-600 The percentage is less than 10%. (vg) Maximum reflectance R in the wavelength range of 300nm to 450nm 60 300-450 The percentage is 12% or less. (vi-g) Maximum reflectance R in the wavelength range of 300 nm to 600 nm 60 300-600 The percentage is 14% or less. [Examples]

[0105] The present invention will be described in more detail by reference to examples. However, the present invention is not limited to the following examples. First, the evaluation method for optical filters in each example and comparative example will be described.

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

[0107] <Thickness measurement> Using a laser displacement meter (manufactured by KEYENCE CORPORATION, product name: LK-H008), the distance from the surface of each optical filter was measured, and by subtracting the thickness of the transparent glass substrate, the thickness of the light absorption film was measured.

[0108] <00​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​In the fabrication of the optical filters according to Example and Comparative Example 5, compounds containing the following metal components were used.

[0116] [Table 2]

[0117] <Example 1> 5.0 g of UV absorber (1-i) and 95.0 g of ethanol were mixed and stirred for 30 minutes to obtain the UV 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 the metal component-containing liquid composition according to Example 1. 2.0 g of the UV 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 the light-absorbing composition according to Example 1. Table 3 shows the content of each component and the mass ratio of the predetermined components in the UV absorber solution, the metal component-containing liquid composition, and the light-absorbing composition. The amount of solids in the light-absorbing composition was determined based on the assumption that the solids content of the silicone resin KR-300 is 50% by mass and the metal component content of compound (2-i) is 6.5% by mass.

[0118] A transparent glass substrate made of borosilicate glass with dimensions of 76 mm × 76 mm × 0.21 mm (manufactured by SCHOTT, product name: D263 T eco) was coated with a light-absorbing composition using a dispenser over a 40 mm × 40 mm area in the center of one main surface to form a coating film. After the obtained coating film was thoroughly dried at room temperature, it was heat-treated in an oven at 160°C for 1 hour to evaporate the solvent and cure it, obtaining a light-absorbing film according to Example 1 that contains an ultraviolet absorber and a metal component. In this way, an optical filter according to Example 1 equipped with the light-absorbing film according to Example 1 was fabricated. The transmission spectrum of the optical filter according to Example 1 is shown in Figure 3. The characteristics related to wavelength and transmittance and the thickness of the light-absorbing film observed from Figure 3 are shown in Table 5.

[0119] <Example 2> 2.0 g of the UV absorber (1-ii) and 98.0 g of toluene were mixed and stirred for 30 minutes to obtain the UV 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 the metal component-containing compound (2-i) were mixed and stirred for 30 minutes to obtain the metal component-containing liquid composition according to Example 2. 5.0 g of the UV 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 the light-absorbing composition according to Example 2. The content of each component and the mass ratio of the predetermined components in the UV absorber solution, the metal component-containing liquid composition, and the light-absorbing composition are shown in Table 3.

[0120] Except for using the light-absorbing composition according to Example 2 instead of the light-absorbing composition according to Example 1 and setting the heat treatment temperature to 120°C, the coating film of the light-absorbing composition was cured on a transparent glass substrate in the same manner as in Example 1 to obtain the light-absorbing film according to Example 2. In this way, an optical filter according to Example 2 equipped with the light-absorbing film according to Example 2 was fabricated. The transmission spectrum of the optical filter according to Example 2 is shown in Figure 4. Furthermore, the characteristics related to wavelength and transmittance and the thickness of the light-absorbing film observed from Figure 4 are shown in Table 5.

[0121] <Examples 3 and 4> The light-absorbing compositions for 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 were changed as shown in Table 3. The light-absorbing films for Examples 3 and 4 were formed by curing the coating film of the light-absorbing composition on a transparent glass substrate in the same manner as in Example 2, except that the light-absorbing compositions for Examples 3 and 4 were used instead of the light-absorbing composition for Example 2, and the optical filters for Examples 3 and 4 were fabricated. The transmission spectra of the optical filters for Examples 3 and 4 are shown in Figures 5 and 6, respectively. The characteristics related to wavelength and transmittance and the thickness of the light-absorbing film, as observed from Figures 5 and 6, are shown in Table 5.

[0122] <Examples 5-8> Except for adjusting the types and content of components as shown in Table 3, the UV absorber solution, the metal component-containing liquid composition, and the light-absorbing composition were prepared in the same manner as in Example 1 to obtain the light-absorbing compositions of Examples 5 to 8. In Examples 5 to 8, compound (2-ii) containing the metal component was used to prepare the metal component-containing liquid composition. In Examples 5 and 6, UV absorber (1-i) was used to prepare the UV absorber solution, and in Examples 7 and 8, UV absorber (1-ii) was used to prepare the UV absorber solution. Assuming that the metal component content in compound (2-ii) is 11.3% by mass, the amount of solids in the light-absorbing composition was determined.

[0123] Except for using the light-absorbing composition according to Example 1, the light-absorbing compositions according to Examples 5 to 8 were used instead, and in the same manner as in Example 1, the coating film of the light-absorbing composition was cured on a transparent glass substrate to form the light-absorbing films according to Examples 5 to 8, and optical filters according to Examples 5 to 8 were fabricated. The transmission spectra of the optical filters according to Examples 5 to 8 are shown in Figures 7 to 10, respectively. Furthermore, the characteristics related to wavelength and transmittance, and the thickness of the light-absorbing film observed from Figures 7 to 10 are shown in Table 5.

[0124] <Examples 9-19> Except for adjusting the types and content of components as shown in Table 3, the UV absorber solution, the metal component-containing liquid composition, and the light-absorbing composition were prepared in the same manner as in Example 1 to obtain the light-absorbing compositions of Examples 9 to 19. In Examples 9 to 17, UV absorber (1-i) was used to prepare the UV absorber solution, and in Examples 18 and 19, UV absorber (1-ii) was used to prepare the UV absorber solution. In Examples 9 to 19, compound (2-iii) containing a metal component was used to prepare the metal component-containing liquid composition. Assuming that the metal component content in compound (2-iii) is 13.2% by mass, the amount of solids in the light-absorbing composition was determined.

[0125] Except for using the light-absorbing composition of Examples 9 to 19 instead of the light-absorbing composition of Example 1, the light-absorbing films of Examples 9 to 19 were cured on a transparent glass substrate in the same manner as in Example 1, and optical filters of Examples 9 to 19 were fabricated. The transmission spectra of the optical filters of Examples 9 to 19 are shown in Figures 11 to 21, respectively. The characteristics related to wavelength and transmittance, as well as the thickness of the light-absorbing film, as observed from Figures 11 to 21, are 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). An optical filter according to Example 20 was fabricated by curing a coating of the light-absorbing composition on a transparent glass substrate 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. The transmission spectrum of the optical filter according to Example 20 is shown in Figure 22. The characteristics related to wavelength and transmittance and the thickness of the light-absorbing film observed from Figure 22 are 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 the light-absorbing composition according to Comparative Example 1. The content of each component in the UV absorber solution and the light-absorbing composition and the mass ratio of the predetermined components are shown in Table 4. Except for using the light-absorbing composition according to Comparative Example 1 instead of the light-absorbing composition according to Example 1, the coating film of the light-absorbing composition was cured on a transparent glass substrate in the same manner as in Example 1 to form the light-absorbing film according to Comparative Example 1, and an optical filter according to Comparative Example 1 was fabricated. The transmission spectrum of the optical filter according to Comparative Example 1 is shown in Figure 23. Furthermore, the characteristics related to wavelength and transmittance and the thickness of the light-absorbing film observed from Figure 23 are shown in Table 5.

[0128] <Comparative Example 2> 5.0 g of the ultraviolet absorber solution according to Example 2 and 10.0 g of a 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. Table 4 shows the contents of the respective components and the mass ratios of the predetermined components in the ultraviolet absorber solution and the light-absorbing composition. A light-absorbing film according to Comparative Example 2 was formed by curing a coating film of the light-absorbing composition on a transparent glass substrate 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, and an optical filter according to Comparative Example 2 was produced. The transmission spectrum of the optical filter according to Comparative Example 2 is shown in FIG. 24. Table 5 shows the characteristics regarding the wavelength and transmittance read from FIG. 24 and the thickness of the light-absorbing film.

[0129] <Comparative Example 3> 2.0 g of the ultraviolet absorber solution according to Example 20 and 10.0 g of a 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. Table 4 shows the contents of the respective components and the mass ratios of the predetermined components in the ultraviolet absorber solution and the light-absorbing composition. A light-absorbing film according to Comparative Example 3 was formed by curing a coating film of the light-absorbing composition on a transparent glass substrate 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, and an optical filter according to Comparative Example 3 was produced. The transmission spectrum of the optical filter according to Comparative Example 3 is shown in FIG. 25. Table 5 shows the characteristics regarding the wavelength and transmittance read from FIG. 25 and the thickness of the light-absorbing film.

[0130] <Comparative Examples 4 and 5> A UV absorber solution according to Comparative Example 4 was prepared in the same manner as in Example 1, except that UV absorber (1-iv) was used instead of UV absorber (1-i). 2.0 g of the UV 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 the light-absorbing composition according to Comparative Example 4. 2.0 g of the UV 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 the light-absorbing composition according to Comparative Example 5. Except that the light-absorbing compositions according to Comparative Examples 4 and 5 were used instead of the light-absorbing composition according to Example 1, the coating film of the light-absorbing composition was cured on a transparent glass substrate to form the light-absorbing films according to Comparative Examples 4 and 5, respectively, and optical filters according to Comparative Examples 4 and 5 were fabricated in the same manner as in Example 1. The transmission spectra of the optical filters according to Comparative Examples 4 and 5 are shown in Figures 26 and 27, respectively. Furthermore, Table 5 shows the characteristics related to wavelength and transmittance, as well as the thickness of the light-absorbing film, as observed from Figures 26 and 27.

[0131] As shown in Table 5, the optical filters according to Examples 1 to 20 have a transmittance T at a wavelength of 400 nm. 400 The value was 1% or less, confirming that the optical filter according to Example 1 has good optical properties, including sufficient ultraviolet absorption capacity. In the optical filters according to Examples 1 to 20, the maximum transmittance T at wavelengths of 300 to 380 nm was M 300-380 It is 1% or less, and in the optical filters relating to examples other than Examples 12, 14-17, T M 300-380 It is 0.5% or less, and in the optical filters relating to examples other than Examples 12 to 17, T M 300-380 The value was 0.15% or less. In the optical filters according to Examples 1 to 20, the average value T of transmittance in the wavelength range of 550 to 570 nm A 550-570 The figure was over 90%.

[0132] Figure 28 shows the transmission spectra of the transparent glass substrates used in each example and comparative example. Based on these transmission spectra, the light absorption films in Examples 1 to 20 have a transmittance T at a wavelength of 400 nm. 400 It was suggested that the percentage was 5% or less.

[0133] The optical filter according to Example 1 and the optical filter according to Comparative Example 1 are compared. In the optical filter according to Comparative Example 1, T 400 The value was 55.25%. The optical filter according to Example 1 showed increased absorption capacity for light around 400 nm and longer wavelengths compared to the optical filter according to Comparative Example 1. This suggests that the wavelength band of light absorption shifts to longer wavelengths due to interactions such as the partial formation of complexes between the metallic component, aluminum, and the ultraviolet absorber within the light absorption film. In addition, the average value T in the optical filter according to Example 1 was A 550-570 The figure was high, exceeding 90%. This suggests that the UV absorber is properly encapsulated in the presence of alkoxy groups, suppressing the appearance of surface irregularities on the light-absorbing film due to bleed-out and the resulting scattering.

[0134] The optical filter according to Example 2 and the optical filter according to Comparative Example 2 are compared. In the optical filter according to Comparative Example 2, T 400 The figure was 36.39%. The optical filter according to Example 2 has increased absorption capacity for light around 400 nm and longer wavelengths compared to the optical filter according to Comparative Example 2. It is presumed that the same circumstances as those between Example 1 and Comparative Example 1 exist between Example 2 and Comparative Example 2.

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

[0136] As shown in Table 5, the UV cutoff wavelength λ in the optical filter according to Example 1 UV and the UV cutoff wavelength λ in the optical filter according to Comparative Example 1 UV The difference is 42 nm. UV cutoff wavelength λ in the optical filter according to Example 2 UV and the UV cutoff wavelength λ in the optical filter according to Comparative Example 2 UV The difference is 41 nm. UV cutoff wavelength λ in the optical filter according to Example 20 UV and the UV cutoff wavelength λ in the optical filter according to Comparative Example 3 UV The difference is 45 nm. From these facts, it can be understood that when a light-absorbing film containing an ultraviolet absorber also contains a metal component, the UV cutoff wavelength shifts to the longer wavelength side compared to when the light-absorbing film contains only an ultraviolet absorber. This phenomenon is understood to occur because the light absorption band of the light-absorbing film shifts to the longer wavelength side, or 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 with a solid-state image sensor. From the viewpoint of improving the characteristics of the optical filter used with a solid-state image sensor, the UV cutoff wavelength λ in the optical filter according to the present invention UV For example, |λ UV -λ UV R |The condition of being greater than or equal to 10 nm is met. λ UV R The UV cutoff wavelength λ of an optical filter manufactured 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, preferably |λ UV -λ UV R The condition |≧20nm or greater is met, and more preferably |λ UV -λ UV R The condition |≧35nm or greater is met, and more preferably |λ UV -λ UV R The condition of being greater than or equal to 40nm is met.

[0137] The evaluation results of the optical filters in Comparative Examples 4 and 5 showed that when benzophenone without a hydroxyl group in the molecule was used as an ultraviolet absorber, the above 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, it was suggested that the presence of a hydroxyl group in one molecule of the ultraviolet absorber is necessary for the UV cutoff wavelength to shift toward longer wavelengths, and that interaction such as complex formation between the hydroxyl group or the hydroxyl group from which hydrogen has been removed and the metal component is necessary. Furthermore, in benzophenone compounds having a hydroxyl group, the mechanism of light absorption is understood to be brought about by a resonance structure related to hydrogen abstraction and acceptance between the carbonyl group and the hydroxyl group within one molecule. Examples of substances in which light absorption occurs due to such hydrogen abstraction and acceptance within one molecule include hydroxybenzophenone, salicylic acid, benzotriazole compounds, and triazine compounds. Benzotriazole compounds and triazine compounds have a hydroxyl group, and a mechanism of hydrogen abstraction and acceptance occurs between it and 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 metal components, it is considered desirable to use UV absorbers that have both a hydroxyl group and a carbonyl group in a single molecule, such as hydroxybenzophenone and salicylic acid.

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

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

[0140] <Example 21> 5.0 g of UV 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 to obtain the 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 predetermined components in the light-absorbing composition according to Example 21 are shown in Table 7. The component ratio of the light-absorbing composition according to Example 21 was determined assuming that the content of the metal component in compound (2-i) containing a metal component was 6.5% by mass, as shown in Table 2.

[0141] A transparent glass substrate made of borosilicate glass with dimensions of 76 mm × 76 mm × 0.21 mm (manufactured by SCHOTT, product name: D263T eco) was coated with the light-absorbing composition according to Example 21 by spin coating on one main surface to form a coating film. After the obtained coating film was thoroughly dried at room temperature, it was 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 and obtain the light-absorbing film according to Example 21. In this way, an optical filter equipped with 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 Figure 29. The reflection spectra of the optical filter according to Example 21 at incident angles of 5°, 40°, 50°, and 60° are shown in Figure 30. Furthermore, Table 8 shows the characteristics related to wavelength and transmittance and the thickness of the light-absorbing film as observed from Figure 29. Table 9 shows the incident 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 The parameters are shown as follows. Table 10 shows the maximum reflectance values ​​in the wavelength range of 300 nm to 450 nm and in the wavelength range of 300 nm to 600 nm for each incident angle 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 high humidity test (damp heat test) by exposing it to an environment of 85°C and 85% relative humidity for 1008 hours. A constant temperature and humidity chamber KCL-2000A manufactured by Tokyo Rikakikai Co., Ltd. was used as the constant temperature and humidity test chamber. The optical filter was removed at 240 hours and 480 hours after the start of the high temperature and high humidity test, and the transmission spectrum of the optical filter was measured. This measurement was performed at 25°C with an incident angle of 0°. Figure 31 shows the transmission spectrum of the optical filter of Example 21 before and after the high temperature and high humidity test. Table 11 shows |λ DH-240 UV -λ UV |value and |T DH-240 480-600 -T m 480-600 |value, |λ DH-480 UV -λ UV |value and |T DH-480 480-600 -T m 480-600 |value, |λ DH-1K UV -λ UV |value and |T DH-1K 480-600 -T m 480-600 This indicates the value of |.

[0143] An optical filter according to Example 21, which had not undergone high-temperature and high-humidity testing, was placed inside a heat cycle chamber and subjected to 1008 heat cycles at 85°C / -40°C. The temperature inside the heat cycle chamber was maintained at 85°C and -40°C for 30 minutes each, and then the temperature was raised or lowered from one temperature to the other over a period of 5 minutes. An ESPEC thermal shock tester TSA-103ES 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 spectrum of the optical filter according to Example 21 before and after the heat cycle test. The measurement was performed at 25°C with an incident angle of 0°. Table 12 shows |λ HC-144 UV -λ UV |value and |T HC-144 480-600 -T m 480-600 |value, |λ HC-576 UV -λ UV |value and |T HC-576 480-600 -T m 480-600 |value, |λ HC-1K UV -λ UV |value and |T HC-1K 480-600 -T m 480-600 This indicates the value of |.

[0144] <Examples 22-35> Based on the materials and manufacturing conditions shown in Tables 1, 2 or 6, and 7, optical filters equipped with the light-absorbing compositions and light-absorbing films according to Examples 22-35 were prepared in the same manner as in Example 21. In Examples 26 and 32, a transparent glass substrate pre-coated with a fluorine compound was used, and after the formation of the light-absorbing film, the light-absorbing film was peeled off from the transparent glass substrate to obtain an optical filter consisting of 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 observed from the transmission spectra of the optical filters according to Examples 22 to 35 at an incident angle of 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 values ​​in the wavelength range of 300 nm to 450 nm and the maximum reflectance values ​​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 for Examples 23, 24, 26, and 32 were subjected to high-temperature, high-humidity tests and heat cycle tests, similar to those for Example 21. Tables 11 and 12 show the parameters of the optical filters for Examples 23, 24, 26, and 32, similar to those for Example 21.

[0148] <Example 36> An anti-reflective coating was applied to both main surfaces of the optical filter of Example 23 to obtain the optical filter according to Example 36. The anti-reflective coating consisted of a single layer film containing silicon oxide such as SiO2, formed by the sol-gel method. A liquid anti-reflective coating precursor (alkoxysilane-containing composition) was prepared, containing at least an alkoxysilane compound and water. 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 these.

[0149] An 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 the light-absorbing film, and the other side was the surface of the transparent glass substrate. In applying the alkoxysilane composition, first, the alkoxysilane composition was applied to one side and left at room temperature for about 1 minute to pre-dry the coating, after which the alkoxysilane composition was applied to the opposite side. Then, the coating was fired at 160°C for about 1 hour to volatilize and remove excess solvent, and the coating was cured by hydrolysis and condensation polymerization of the alkoxysilane to obtain an anti-reflective film. In this way, the optical filter according to Example 36 was obtained. The obtained anti-reflective film was porous, and its film thickness was approximately 180 nm.

[0150] The transmission spectra of the optical filter according to Example 36 were 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 observed from the transmission spectrum of the optical filter according to Example 36 at an incident angle of 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 values ​​for the optical filter according to Example 36 in the wavelength range of 300nm to 450nm and in the wavelength range of 300nm to 600nm for each incident angle.

[0152] <Examples 37-41> Based on the materials and manufacturing conditions described in Tables 1, 2, and 7, optical filters equipped with the light-absorbing compositions and light-absorbing films according to Examples 37-41 were fabricated in the same manner as in Example 21. For Examples 37-41, the 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 parameters that can be observed from the transmission spectra of the optical filters of Examples 37-41 at an incident angle of 0°.

[0153] <Comparative Example 6> Based on the materials and manufacturing conditions described in Tables 1, 2, and 7, an optical filter equipped with the light-absorbing composition and light-absorbing film according to Comparative Example 6 was fabricated in the same manner as in Example 21. For Comparative Example 6, the transmission spectra were 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 the parameters that can be observed from the transmission spectrum of the optical filter of Comparative Example 6 at an incident angle of 0°.

[0154] [Table 3]

[0155] [Table 4]

[0156] [Table 5]

[0157] [Table 6]

[0158] [Table 7]

[0159] Table 8

[0160] Table 9

[0161] Table 10

[0162] Table 11

[0163] Table 12

Claims

1. UV absorbers having hydroxyl groups and carbonyl groups in their molecules, It contains metal components, At least a portion of the aforementioned metal component is bonded to an organic oxy group. Light-absorbing composition.

2. The light-absorbing composition according to claim 1, wherein the hydroxyl group and the carbonyl group are separated by 1 to 3 atoms.

3. In the transmission spectrum of the light-absorbing film obtained by curing the light-absorbing composition, at an incident angle of 0 degrees, the transmittance T at a wavelength of 400 nm is... 400 The light-absorbing composition according to claim 1, wherein the amount is 5% or less.

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

5. The light-absorbing composition according to claim 1, wherein the ultraviolet absorber comprises a benzophenone compound represented by the following formula (A2). 【Chemistry 2】 [In formula (A2), R 31 R 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. In formula (A2), R 41 and R 42 R may be a hydroxyl 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. 41 and R 42 It does not have to exist. In formula (A2), multiple R 41 There may be multiple R 42 It may exist.

6. The light-absorbing composition according to claim 1, wherein the ultraviolet absorber comprises a salicylic acid compound represented by the following formula (B). 【Transformation 3】 [In equation (B), R 51 R may be a hydroxyl group, a carboxyl 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. In formula (B), multiple R 51 It is possible that R exists, 51 It is not necessary for R to exist. In equation (B), 52 This is a hydrogen atom, an aryl group, or an aryl halide group in which one or more hydrogen atoms are substituted with halogen atoms.

7. The light-absorbing composition according to claim 1, comprising an alkoxide containing the aforementioned metal component.

8. The light-absorbing composition according to 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. The light-absorbing composition according to claim 1, further comprising a curable resin.

10. The light-absorbing composition according to claim 9, wherein the resin is a silicone resin.

11. The light-absorbing composition according to claim 1, wherein the molar ratio of the content of the ultraviolet absorber to the content of the metal component is 0.001 to 10.

12. UV absorbers having hydroxyl groups and carbonyl groups in their molecules, It contains metal components, At least a portion of the aforementioned metal component is bonded to an organic oxy group. Light-absorbing film.

13. The light-absorbing film according to claim 12, wherein the hydroxyl group and the carbonyl group are separated by 1 to 3 atoms.

14. In the transmission spectrum at an incident angle of 0 degrees, the transmittance T at a wavelength of 400 nm is shown. 400 The light-absorbing film according to claim 12 or 13, wherein the amount is 5% or less.

15. The light-absorbing film according to claim 12, wherein the ultraviolet absorber comprises a benzophenone 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 them is a hydroxyl group. In formula (A1), R 11 , R 12 , R 21 , or R 22 If the functional group is not a hydroxyl group, then multiple R 11 , multiple R 12 , multiple R 21 , or multiple R 22 It is possible that R exists, 11 , R 12 , R 21 , and R 22 At least one of these may not be present.

16. The light-absorbing film according to claim 12, wherein the ultraviolet absorber comprises a benzophenone compound represented by the following formula (A2). 【Transformation 5】 [In formula (A2), R 31 R 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. In formula (A2), R 41 and R 42 R may be a hydroxyl 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. 41 and R 42 It does not have to exist. In formula (A2), multiple R 41 There may be multiple R 42 It may exist.

17. The light-absorbing film according to claim 12, wherein the ultraviolet absorber comprises a salicylic acid compound represented by the following formula (B). 【Transformation 5】 [In equation (B), R 51 R may be a hydroxyl group, a carboxyl 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. In formula (B), multiple R 51 It is possible that R exists, 51 It is not necessary for R to exist. In equation (B), 52 This is a hydrogen atom, an aryl group, or an aryl halide group in which one or more hydrogen atoms are substituted with halogen atoms.

18. The light-absorbing film according to claim 12, comprising an alkoxide containing the aforementioned metal component.

19. 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 containing a silicone resin.

21. The method includes curing the light-absorbing composition according to any one of claims 1 to 11 by heating it at a temperature of 120°C or higher. A method for manufacturing a light-absorbing film.

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

23. In the transmission spectrum at an incident angle of 0 degrees, the maximum transmittance T is the value within the wavelength range of 300 to 380 nm. M 300-380 The optical filter according to claim 22, wherein the content is 3% or less.

24. In the transmission spectrum in the wavelength range of 300 to 520 nm, the ultraviolet cutoff wavelength λ is such that the transmittance is 50%. UV 405 nm ≤ λ UV The optical filter according to claim 22, wherein the wavelength is ≤ 500 nm.

25. Average value T of transmittance in the wavelength range of 550-570 nm A 550-570 The optical filter according to claim 22, wherein the amount is 87% or more.

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