JP6646179B2 - Optical filter - Google Patents

Description

  The present invention relates to an optical filter and a composition for an optical filter.

  In an imaging device using a solid-state imaging device such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), various optical filters are arranged in front of the solid-state imaging device to obtain an image having good color reproducibility. Have been. Generally, a solid-state imaging device has a spectral sensitivity in a wide wavelength range from an ultraviolet region to an infrared region. On the other hand, human visibility is present only in the visible light region. For this reason, a technique is known in which an optical filter that blocks infrared rays or ultraviolet rays is arranged on the front surface of the solid-state imaging device in order to make the spectral sensitivity of the solid-state imaging device in the imaging device close to human visibility.

  For example, Patent Document 1 has a UV-IR absorption layer capable of absorbing infrared rays and ultraviolet rays, and has a predetermined transmission characteristic when light having a wavelength of 300 nm to 1200 nm is incident at an incident angle of 0 ° and 40 °. An optical filter is described. The UV-IR absorption layer of this optical filter contains a UV-IR absorber formed by phosphonic acid and copper ions.

Japanese Patent No. 6232161

  Although the optical filter described in Patent Literature 1 has a desired characteristic with respect to transmittance, Haze of this optical filter is not considered at all in Patent Literature 1. Thus, the present invention provides an optical filter having a desired haze while containing a UV-IR absorber formed by phosphonic acid and copper ions.

The present invention
With a UV-IR absorption layer containing a UV-IR absorber capable of absorbing ultraviolet light and infrared light formed by phosphonic acid and copper ions,
The phosphonic acid includes a phosphonic acid having a phenyl group or a halogenated phenyl group in which at least one hydrogen atom in the phenyl group is substituted with a halogen atom,
Having a haze of 5% or less,
An optical filter is provided.

  The optical filter has a haze of 5% or less while including a UV-IR absorber formed by phosphonic acid and copper ions.

FIG. 1A is a sectional view showing an example of the optical filter of the present invention. FIG. 1B is a cross-sectional view illustrating another example of the optical filter of the present invention. FIG. 1C is a sectional view showing still another example of the optical filter of the present invention. FIG. 1D is a sectional view showing still another example of the optical filter of the present invention. FIG. 1E is a sectional view showing still another example of the optical filter of the present invention. FIG. 1F is a sectional view showing still another example of the optical filter of the present invention. FIG. 2 is a sectional view showing an example of a camera module including the optical filter of the present invention. FIG. 3 is a transmittance spectrum of the optical filter according to the first embodiment. FIG. 4 is a transmittance spectrum of the optical filter according to the fourth embodiment. FIG. 5 is a transmittance spectrum of the optical filter according to Example 13. FIG. 6 is a transmittance spectrum of the optical filter according to Example 14. FIG. 7 is a transmittance spectrum of the optical filter according to Example 15. FIG. 8 is a transmittance spectrum of the optical filter according to Comparative Example 1.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following description relates to an example of the present invention, and the present invention is not limited thereto.

  As described in Patent Document 1, an optical filter including a UV-IR absorbing layer including a UV-IR absorbing agent formed by phosphonic acid and copper ions may have desired characteristics with respect to transmittance. On the other hand, the present inventors have newly found that an optical filter having a UV-IR absorption layer containing a UV-IR absorber formed by phosphonic acid and copper ions does not always have a desirable haze. Was. Haze corresponds to a percentage of diffuse transmittance with respect to total light transmittance. For example, according to Japanese Industrial Standard (JIS) K7136: 2000, among light transmitted through a test piece, 0.1% from incident light due to forward scattering. It is defined as a percentage of transmitted light that deviates by more than 044 rad (2.5 °). In this specification, the definition of haze conforms to JIS K 7136: 2000, and the haze is measured according to JIS K 7136: 2000.

  If the optical filter has desirable characteristics in terms of transmittance but has high haze, placing the optical filter on the front surface of the solid-state imaging device of the imaging device may degrade the quality of an image obtained by the imaging device. . For example, problems such as uneven color, bleeding, occurrence of flare, and decrease in lightness may occur in an image. Therefore, the present inventors have repeatedly studied day and night on a technique for keeping haze low in an optical filter including a UV-IR absorption layer containing a UV-IR absorber formed of phosphonic acid and copper ions. As a result, the present inventors have found that the dispersion state of the UV-IR absorber formed by phosphonic acid and copper ions in the composition for producing an optical filter may affect the haze of the optical filter. I found something new. Even if the dispersion state of the UV-IR absorber formed by phosphonic acid and copper ions is appropriate from the viewpoint of achieving the desired transmittance in the optical filter, this dispersion state is advantageous for achieving a low haze. Is not always found. Further, based on this newly discovered finding, it has been newly discovered that the dispersion state of the UV-IR absorber formed by sulfonic acid and copper ions may affect the haze of the optical filter. Was. Then, the present inventors have repeatedly devised a great deal of trial and error and finally devised an optical filter having a low haze.

  As shown in FIG. 1A, the optical filter 1a includes a UV-IR absorption layer 10. The UV-IR absorption layer 10 contains a UV-IR absorber formed by at least one acid of phosphonic acid and sulfonic acid and copper ions and capable of absorbing ultraviolet light and infrared light. The optical filter 1a has a haze of 5% or less. For this reason, a high-quality image can be obtained by the imaging device in which the optical filter 1a is incorporated.

  The optical filter 1a desirably has a haze of 4% or less. Thereby, a high-quality image can be obtained more reliably by the imaging device incorporating the optical filter 1a. The optical filter 1a desirably has a haze of 1% or less. Thereby, a higher quality image can be obtained by the imaging device in which the optical filter 1a is incorporated.

The optical filter 1a desirably exhibits the following optical performances (i) to (iv) when light having a wavelength of 300 nm to 1200 nm is incident at an incident angle of 0 °. When the optical filter 1a exhibits the following optical performance together with the haze of 5% or less, a high-quality image can be obtained in an imaging device in which the optical filter 1a is incorporated.
(I) an average transmittance of 78% or more at a wavelength of 450 nm to 600 nm; (ii) a spectral transmittance of 1% or less at a wavelength of 300 nm to 350 nm; and (iii) a spectral transmittance and a wavelength which decrease with an increase in the wavelength of 600 nm to 750 nm. First IR cut-off wavelength (iv) existing in the range of 610 nm to 680 nm (iv) Spectral transmittance increasing with increasing wavelength at wavelengths of 350 nm to 450 nm and first UV cut-off wavelength existing in the range of wavelengths of 380 nm to 430 nm

  In the present specification, “spectral transmittance” is a transmittance when incident light of a specific wavelength is incident on an object such as a sample, and “average transmittance” is a spectral transmittance within a predetermined wavelength range. It is an average value of the transmittance, and in this specification, the “transmittance spectrum” is obtained by arranging the spectral transmittance at each wavelength within a predetermined wavelength range in order of wavelength.

  In this specification, the “IR cutoff wavelength” indicates a 50% spectral transmittance in a wavelength range of 600 nm or more when light having a wavelength of 300 nm to 1200 nm is incident on an optical filter at a predetermined incident angle. Means wavelength. The “first IR cutoff wavelength” is an IR cutoff wavelength when light is incident on the optical filter at an incident angle of 0 °. The “UV cutoff wavelength” refers to a wavelength that exhibits 50% spectral transmittance in a wavelength range of 450 nm or less when light having a wavelength of 300 nm to 1200 nm is incident on an optical filter at a predetermined incident angle. means. The “first UV cutoff wavelength” is a UV cutoff wavelength when light is incident on the optical filter at an incident angle of 0 °.

  Since the optical filter 1a exhibits the optical performances (i) to (iv) described above, the optical filter 1a has a large transmission amount of light having a wavelength of 450 nm to 600 nm, and a light having a wavelength of 300 nm to 400 nm and a wavelength of 650 nm or more. Can be effectively cut. For this reason, the transmittance spectrum of the optical filter 1a matches human visibility. Moreover, even if the optical filter 1a does not include a layer other than the UV-IR absorption layer 10, the above optical performances (i) to (iv) can be exhibited, and a haze of 5% or less can be realized.

  Regarding (i) above, the optical filter 1a preferably has an average transmittance of 80% or more, and more preferably 82% or more, at a wavelength of 450 nm to 600 nm.

  Regarding (ii) above, the optical filter 1a desirably has a spectral transmittance of 0.5% or less at a wavelength of 300 nm to 350 nm. Thereby, the optical filter 1a can more effectively cut the light in the ultraviolet region.

  Regarding the above (iii), the first IR cutoff wavelength (wavelength indicating a spectral transmittance of 50%) desirably exists in the wavelength range of 610 nm to 660 nm, and more desirably, in the wavelength range of 610 nm to 650 nm. Exists. As a result, the transmittance spectrum of the optical filter 1a is more suitable for human visibility.

  Regarding the above (iv), the first UV cutoff wavelength (wavelength showing a spectral transmittance of 50%) desirably exists in the range of 390 nm to 430 nm, and more desirably, in the range of 400 nm to 425 nm. Exists. As a result, the transmittance spectrum of the optical filter 1a is more suitable for human visibility.

The optical filter 1a desirably exhibits the following optical performance (v) when light having a wavelength of 300 nm to 1200 nm is incident at an incident angle of 0 °. Thereby, the optical filter 1a can effectively cut the light in the near infrared region.
(V) Spectral transmittance of 5% or less at wavelengths of 750 nm to 1080 nm

The optical filter 1a desirably exhibits the following optical performance (vi) when light having a wavelength of 300 nm to 1200 nm is incident at an incident angle of 0 °. Thereby, infrared rays having a relatively long wavelength (wavelengths from 1000 to 1100 nm) can be cut. Conventionally, in order to cut off light of this wavelength, a light reflection film composed of a dielectric multilayer film is often used. However, according to the optical filter 1a, light of this wavelength can be effectively cut without using such a dielectric multilayer film. Even if a light reflection film composed of a dielectric multilayer film is required, the level of reflection performance required for the light reflection film can be lowered, so that the number of stacked dielectrics in the light reflection film can be reduced, and the light reflection film Cost required for formation can be reduced.
(Vi) Spectral transmittance of 10% or less at wavelengths of 1000 to 1100 nm

The optical filter 1a desirably exhibits the following optical performance (vii) when light having a wavelength of 300 nm to 1200 nm is incident at an incident angle of 0 °. In this case, infrared rays having wavelengths of 1100 to 1200 nm can be cut. Thus, the optical filter 1a can effectively cut off light of this wavelength without using a dielectric multilayer film or with a small number of dielectric layers in the dielectric multilayer film.
(Vii) Spectral transmittance of 15% or less at wavelengths of 1100 to 1200 nm

  The phosphonic acid forming the UV-IR absorber in the UV-IR absorption layer 10 includes, for example, a primary phosphonic acid having an aryl group. This makes it easier for the optical filter 1a to exhibit the above-mentioned optical characteristics (i) to (iv).

  The aryl group of the first phosphonic acid is, for example, a phenyl group, a benzyl group, a toluyl group, a nitrophenyl group, a hydroxyphenyl group, a halogenated phenyl group in which at least one hydrogen atom in the phenyl group is substituted with a halogen atom, Or a halogenated benzyl group in which at least one hydrogen atom in the benzyl group is substituted with a halogen atom. Desirably, the primary phosphonic acid has, in part, a halogenated phenyl group. In this case, the optical filter 1a can more reliably exhibit the optical performances (i) to (iv) described above.

  The phosphonic acid forming the UV-IR absorber in the UV-IR absorption layer 10 desirably further includes a second phosphonic acid having an alkyl group. In the second phosphonic acid, the alkyl group is attached to the phosphorus atom. The alkyl group of the second phosphonic acid may be an aromatic alkyl group. For example, a phenylmethyl group, a phenylethyl group, a phenylpropyl group, a phenylbutyl group, a phenylheptyl group, and a phenylhexyl group can be exemplified. The aromatic alkyl group may be a halogenated aromatic alkyl group. The halogenated aromatic alkyl group is, for example, a halogenated phenylalkyl group in which at least one hydrogen atom in a phenyl group is substituted with a halogen atom.

  The alkyl group of the second phosphonic acid is, for example, an alkyl group having 6 or less carbon atoms. This alkyl group may have any of a straight chain and a branched chain. Further, as described above, the alkyl group of the second phosphonic acid may have an aromatic substituent or a halogenated aromatic substituent.

  The sulfonic acid forming the UV-IR absorber in the UV-IR absorption layer 10 includes, for example, a primary sulfonic acid having an aryl group. This makes it easier for the optical filter 1a to exhibit the above-mentioned optical characteristics (i) to (iv). The aryl group of the primary sulfonic acid is, for example, a phenyl group, a benzyl group, a toluyl group, a nitrophenyl group, a hydroxyphenyl group, or a halogenated phenyl group in which at least one hydrogen atom in the phenyl group is substituted with a halogen atom. . Or a halogenated benzyl group in which at least one hydrogen atom in the benzyl group is substituted with a halogen atom. The primary sulfonic acid can be benzenesulfonic acid, p-toluenesulfonic acid, 4-bromobenzenesulfonic acid, 4-methylbenzylsulfonic acid, or 4-bromobenzylsulfonic acid.

  The sulfonic acid forming the UV-IR absorber in the UV-IR absorption layer 10 desirably further includes a second sulfonic acid having an alkyl group. The second sulfonic acid is, for example, a sulfonic acid having a methyl group, an ethyl group, a propyl group, a butyl group, a heptyl group, or a hexyl group. The alkyl group of the second sulfonic acid may have an aromatic substituent.

  The UV-IR absorption layer 10 desirably further includes a phosphate ester for dispersing the UV-IR absorber and a matrix resin.

The phosphate ester contained in the UV-IR absorption layer 10 is not particularly limited as long as the UV-IR absorber can be appropriately dispersed. For example, a phosphate diester represented by the following formula (c1) and a phosphate diester represented by the following formula ( at least one of the phosphoric acid monoesters represented by c2). In the following formulas (c1) and (c2), R ₂₁ , R ₂₂ , and R ₃ are each a monovalent functional group represented by — (CH ₂ CH ₂ O) _n R ₄ , and n Is an integer of 1 to 25, and R ₄ represents an alkyl group having 6 to 25 carbon atoms. R ₂₁ , R ₂₂ , and R ₃ are the same or different types of functional groups.

  The phosphate ester is not particularly limited. For example, Plysurf A208N: polyoxyethylene alkyl (C12, C13) ether phosphate, Plysurf A208F: polyoxyethylene alkyl (C8) ether phosphate, Plysurf A208B: Polyoxyethylene lauryl ether phosphate, Plysurf A219B: Polyoxyethylene lauryl ether phosphate, Plysurf AL: Polyoxyethylene styrenated phenyl ether phosphate, Plysurf A212C: Polyoxyethylene tridecyl ether phosphate Or Plysurf A215C: polyoxyethylene tridecyl ether phosphate. These are all products manufactured by Daiichi Kogyo Seiyaku. The phosphoric acid ester is NIKKOL DDP-2: polyoxyethylene alkyl ether phosphate, NIKKOL DDP-4: polyoxyethylene alkyl ether phosphate, or NIKKOL DDP-6: polyoxyethylene alkyl ether phosphate. possible. These are all products made by Nikko Chemicals.

  The matrix resin contained in the UV-IR absorption layer 10 is, for example, a resin in which a UV-IR absorber can be dispersed and which can be cured by heat or ultraviolet. Furthermore, when a resin layer having a thickness of 0.1 mm is formed as the matrix resin, the transmittance of the resin layer at a wavelength of 350 nm to 900 nm is, for example, 70% or more, preferably 75% or more, and more preferably. Is 80% or more of a resin. The content of at least one acid of phosphonic acid and sulfonic acid is, for example, 5 to 400 parts by mass with respect to 100 parts by mass of the matrix resin.

  The matrix resin contained in the UV-IR absorption layer 10 is not particularly limited as long as it satisfies the above-mentioned characteristics. Sulfone resin, polyamideimide resin, (modified) acrylic resin, epoxy resin, or silicone resin. The matrix resin may contain an aryl group such as a phenyl group, and is preferably a silicone resin containing an aryl group such as a phenyl group. If the UV-IR absorption layer 10 is hard (rigid), cracks are likely to occur due to curing shrinkage during the manufacturing process of the optical filter 1a as the thickness of the UV-IR absorption layer 10 increases. When the matrix resin is a silicone resin containing an aryl group, the UV-IR absorption layer 10 tends to have good crack resistance. In addition, when a silicone resin containing an aryl group is used, the UV-IR absorber formed by at least one of the above-described phosphonic acid and sulfonic acid and copper ions does not easily aggregate. Further, when the matrix resin of the UV-IR absorption layer 10 is a silicone resin containing an aryl group, the phosphoric acid ester contained in the UV-IR absorption layer 10 is a phosphoric acid represented by the formula (c1) or (c2). It is desirable to have a flexible linear organic functional group such as an oxyalkyl group such as an acid ester. Because of the interaction based on the combination of at least one of the above-mentioned phosphonic acid and sulfonic acid, a silicone resin containing an aryl group, and a phosphoric ester having a linear organic functional group such as an oxyalkyl group, UV- This is because the IR absorber hardly agglomerates and can provide the UV-IR absorption layer 10 with good rigidity and good flexibility. Specific examples of the silicone resin used as the matrix resin include KR-255, KR-300, KR-2621-1, KR-211, KR-311, KR-216, KR-212, and KR-251. be able to. These are all silicone resins manufactured by Shin-Etsu Chemical Co., Ltd.

  The optical filter 1a further includes a hydrolysis-condensation product of an alkoxysilane monomer, if necessary. When the optical filter 1a contains a hydrolysis-condensation product of an alkoxysilane monomer, the optical filter 1a has good moisture resistance due to the siloxane bond (-Si-O-Si-) of the hydrolysis-condensation product of the alkoxysilane monomer. . In addition, the optical filter 1a has good heat resistance. This is because a siloxane bond has a higher binding energy than a bond such as a -CC- bond or a -CO- bond, is chemically stable, and has excellent heat resistance and moisture resistance.

  The UV-IR absorption layer 10 in the optical filter 1a can be formed by curing a coating film of a predetermined optical filter composition.

  The composition for an optical filter contains at least one acid of phosphonic acid and sulfonic acid, and copper ions. In addition, when the composition for an optical filter is formed by curing a coating film of the composition to form a layer having a thickness of 100 to 300 μm, the layer can absorb ultraviolet rays and infrared rays, and Is adjusted to have a haze of 5% or less (preferably 4% or less). It is sufficient that such characteristics appear when the layer of the cured product of the composition for an optical filter has a specific thickness included in the range of 100 to 300 μm. That is, the layer of the cured product of the composition for an optical filter does not have to satisfy such characteristics in all the ranges of 100 to 300 μm.

The composition for an optical filter desirably cures a coating film of the composition to form a layer having a thickness of 100 to 300 μm, and allows light having a wavelength of 300 nm to 1200 nm to enter this layer at an incident angle of 0 °. In this case, the composition is prepared so as to satisfy the following conditions (I) to (IV).
(I) It has an average transmittance of 78% or more at a wavelength of 450 nm to 600 nm.
(II) It has a spectral transmittance of 1% or less at a wavelength of 300 nm to 350 nm.
(III) The first IR cut-off wavelength having a spectral transmittance that decreases with an increase in the wavelength at a wavelength of 600 nm to 750 nm and a spectral transmittance of 50% at a wavelength of 600 nm to 750 nm falls within a range of a wavelength of 610 nm to 680 nm. Exists.
(IV) The first UV cut-off wavelength having a spectral transmittance that increases with an increase in the wavelength at a wavelength of 350 nm to 450 nm and having a spectral transmittance of 50% at a wavelength of 350 nm to 450 nm is within a range of a wavelength of 380 nm to 430 nm. Exists.

  The composition for an optical filter has, for example, a viscosity of 1 to 200 mPa · s at 22 to 23 ° C. In this case, the optical filter composition tends to flow, which seems to be disadvantageous for forming a coating film with the optical filter composition. In addition, it is necessary to add a relatively large amount of a solvent (dispersion medium) to adjust the viscosity of the composition for an optical filter to such a range, and a process for curing a coating film of the composition for an optical filter is required. May be longer. For this reason, until now, it is desirable that the present inventors prepare the composition for an optical filter so that the viscosity at 22 to 23 ° C. exceeds the viscosity of 200 mPa · s (for example, 300 mPa · s or more). I was thinking. On the other hand, the present inventors have drastically reviewed the viscosity of the optical filter composition from the viewpoint of reducing the haze of the UV-IR absorption layer obtained by curing the coating film of the optical filter composition. As a result, it has been newly found that it is desirable to adjust the viscosity at 22 to 23 ° C. of the composition for an optical filter to 1 to 200 mPa · s from the viewpoint of reducing the haze of the UV-IR absorption layer. Even when the above-mentioned UV-IR absorber is agglomerated to such an extent that the transmittance characteristics of the UV-IR absorption layer are not affected in the optical filter composition, the state of aggregation in the coating film of the optical filter composition is Unless properly resolved, it is considered that the haze of the UV-IR absorption layer tends to increase. On the other hand, when the composition for an optical filter has a viscosity of 1 to 200 mPa · s at 22 to 23 ° C., the composition for an optical filter flows appropriately in a coating film of the composition for an optical filter, and the UV-IR absorber It is considered that the cohesion state of is easily dissolved. As a result, it is considered that the haze of the UV-IR absorption layer can be reduced. When the viscosity at 22 to 23 ° C. of the composition for an optical filter is lower than 1 mPa · s, the amount of the solvent in the composition for an optical filter is too large, and the physical distance of the components constituting the UV-IR absorption layer is reduced. growing. For this reason, there is a possibility that the UV-IR absorption layer cannot be formed properly.

  The viscosity of the composition for an optical filter at 22 to 23 ° C. can be measured using, for example, a vibrating viscometer (probe: PR-10L, controller: VM-10A) manufactured by Sekonic Corporation.

  The composition for an optical filter desirably has a viscosity of 2 to 180 mPa · s at 22 to 23 ° C., and more desirably has a viscosity of 2 to 160 mPa · s at 22 to 23 ° C. Thereby, the haze of the UV-IR absorption layer obtained by curing the coating film of this composition can be more reliably reduced to 5% or less.

  In the composition for optical filters, the solid content is, for example, 3 to 17% by mass. In this case, it is considered that the content of the solid content is relatively small, the optical filter composition easily flows appropriately in the coating film of the optical filter composition, and the haze of the UV-IR absorption layer is easily reduced.

  In the composition for an optical filter, the solid content is desirably 5 to 17% by mass, and more desirably 6 to 17% by mass.

  In the composition for optical filters, the content of copper ions is, for example, 0.5 to 2.2% by mass. In this case, the content of copper ions in the composition is relatively small, the aggregation of the UV-IR absorber hardly occurs in the coating film of the composition for an optical filter, and the haze of the UV-IR absorption layer is easily reduced. Can be

  In the composition for optical filters, the content of copper ions is desirably 0.6 to 2.1% by mass.

  The composition for an optical filter contains a component contained in the UV-IR absorption layer 10 or a precursor of the component. The composition for an optical filter further contains, for example, a predetermined solvent (dispersion medium). The composition for an optical filter may include, for example, an alkoxysilane monomer. When the composition for an optical filter contains an alkoxysilane monomer, it is possible to suppress aggregation of the particles of the UV-IR absorber in the composition for an optical filter, and to reduce the content of the phosphoric acid ester even when the content of the phosphoric acid ester is reduced. The UV-IR absorber is well dispersed in the filter composition.

  An example of a method for manufacturing the optical filter 1a will be described. First, an example of a method for preparing the composition for an optical filter will be described. A copper salt such as copper acetate monohydrate is added to a predetermined solvent such as tetrahydrofuran (THF) and stirred to obtain a copper salt solution. Next, a phosphoric acid ester compound such as a phosphoric acid diester represented by the formula (c1) or a phosphoric acid monoester represented by the formula (c2) is added to the copper salt solution and stirred to prepare a solution A. I do. Further, the first phosphonic acid or the first sulfonic acid is added to a predetermined solvent such as THF and stirred to prepare a solution B. When a plurality of types of phosphonic acids or sulfonic acids are used as the first phosphonic acid or the first sulfonic acid, the first phosphonic acid or the first sulfonic acid is added to a predetermined solvent such as THF, and the mixture is stirred. Liquid B may be prepared by mixing a plurality of preliminary liquids prepared for each type of acid or primary sulfonic acid. In the preparation of the liquid B, an alkoxysilane monomer may be added.

  Next, while stirring the liquid A, the liquid B is added to the liquid A and stirred for a predetermined time. Next, a predetermined solvent such as toluene is added to this solution and stirred to obtain a liquid C. Next, a desolvation treatment is performed for a predetermined time while heating the liquid C to obtain a liquid D. As a result, components generated by dissociation of a solvent such as THF and a copper salt such as acetic acid (boiling point: about 118 ° C.) are removed, and the UV-IR absorber is formed by primary phosphonic acid or primary sulfonic acid and copper ions. Generated. The temperature at which the liquid C is heated is determined based on the boiling point of the component to be removed dissociated from the copper salt. In the desolvation treatment, a solvent such as toluene (boiling point: about 110 ° C.) used for obtaining the liquid C also volatilizes, but the solvent remains in the liquid D so that the viscosity of the liquid D is in a desired range. I do. The addition amount of the solvent for obtaining the solution C may be adjusted so that the viscosity of the solution D is in a desired range, or the time of the desolvation treatment may be adjusted.

  When the composition for an optical filter further contains a second phosphonic acid or a second sulfonic acid, for example, the H solution is further prepared as follows. First, a copper salt such as copper acetate monohydrate is added to a predetermined solvent such as tetrahydrofuran (THF) and stirred to obtain a copper salt solution. Next, to this copper salt solution, a phosphate ester compound such as a phosphate diester represented by the formula (c1) or a phosphate monoester represented by the formula (c2) is added and stirred to prepare a solution E. I do. In addition, the second phosphonic acid or the second sulfonic acid is added to a predetermined solvent such as THF and stirred to prepare a solution F. When a plurality of types of phosphonic acids or sulfonic acids are used as the second phosphonic acid or the second sulfonic acid, the second phosphonic acid or the second sulfonic acid is added to a predetermined solvent such as THF, and then stirred to form the second phosphonic acid or the second sulfonic acid. Alternatively, a plurality of preliminary liquids prepared for each type of the second sulfonic acid may be mixed to prepare the liquid F. While stirring the solution E, the solution F is added to the solution E and stirred for a predetermined time. Next, a predetermined solvent such as toluene is added to this solution and stirred to obtain a solution G. Next, a solution H is obtained by performing a desolvation treatment for a predetermined time while heating the solution G. As a result, components generated by dissociation of a solvent such as THF and a copper salt such as acetic acid are removed, and another UV-IR absorber is formed by the second phosphonic acid or the second sulfonic acid and the copper ions. The temperature at which solution G is heated is determined in the same manner as solution C, and the solvent for obtaining solution G is also determined in the same manner as solution C. The amount of the solvent for obtaining the solution G is not particularly limited.

  A composition for an optical filter can be prepared by adding a matrix resin such as a silicone resin to the liquid D and stirring the mixture. In addition, when the composition for an optical filter contains a UV-IR absorber formed by a second phosphonic acid or a second sulfonic acid and copper ions, a matrix resin such as a silicone resin is added to the liquid D and stirred. The composition for an optical filter can be prepared by further adding the solution H to the solution I obtained as described above and stirring the solution.

Next, the optical filter composition is applied to one main surface of a predetermined substrate to form a coating film. Although the substrate is not particularly limited, a glass substrate, a resin substrate, or a metal substrate (a steel substrate or a stainless steel substrate) can be used. For example, a liquid optical filter composition is applied to one main surface of a substrate by spin coating, die coating, or application by a dispenser to form a coating film. Next, the coating film is subjected to a predetermined heat treatment to cure the coating film. For example, this coating film is exposed to an environment at a temperature of 40C to 200C. If necessary, the coating film is subjected to a humidifying treatment in order to sufficiently hydrolyze and polycondense the alkoxysilane monomer contained in the composition for an optical filter. For example, the cured coating is exposed to an environment at a temperature of 40C to 100C and a relative humidity of 40% to 100%. As a result, a repeating structure of siloxane bonds (Si—O) _n is formed. Generally, in the hydrolysis and polycondensation reaction of an alkoxysilane containing a monomer, the alkoxysilane and water may be allowed to coexist in a liquid composition to carry out these reactions. However, if water is added to the optical filter composition before manufacturing the optical filter, the phosphate ester or the UV-IR absorber deteriorates in the process of forming the UV-IR absorption layer, and the UV -There is a possibility that the IR absorption performance is reduced or the durability of the optical filter is impaired. For this reason, it is desirable to perform a humidification treatment after the coating film is cured by a predetermined heat treatment. Thus, the UV-IR absorption layer 10 can be formed on the substrate. Thereafter, the UV-IR absorption layer 10 is peeled off from the substrate to obtain the optical filter 1a. The optical filter 1a has a simple configuration and is easily thinned. Therefore, the optical filter 1a can contribute to lowering the height of the imaging device and the optical system.

  As described above, the composition for an optical filter has a relatively low viscosity of, for example, 1 to 200 mPa · s at 22 to 23 ° C. In this case, the composition for optical filters contains a relatively large amount of solvent. Therefore, when the coating film of the composition for an optical filter is cured by heating, if the coating film is heated at a high temperature from the beginning, the UV-IR absorption layer is likely to crack due to rapid evaporation of the solvent. For this reason, after heating the coating film of the composition for an optical filter for a predetermined time in a relatively low temperature environment of 60 ° C. or less, it is possible to heat the coating film for a predetermined time in a relatively high temperature environment having a temperature exceeding 60 ° C. desirable. While the solvent is volatilized slowly, the bonding by the condensation polymerization reaction of the alkoxysilane monomer or the silicone resin proceeds in parallel, thereby preventing the UV-IR absorption layer from being cracked. As a result, an optical filter having desired transmittance characteristics and low haze can be stably manufactured. The coating film of the composition for an optical filter is desirably heated in an environment of 60 ° C. or lower for 10 minutes or more and then exposed to an environment of higher than 60 ° C. More desirably, the coating film of the composition for an optical filter is heated in an environment of 45 ° C. or lower for 20 minutes or more and then exposed to an environment of higher than 60 ° C.

<Modification>
The optical filter 1a can be changed from various viewpoints. For example, the optical filter 1a may be changed to the optical filters 1b to 1f shown in FIGS. 1B to 1F, respectively. The optical filters 1b to 1f have the same configuration as that of the optical filter 1a, unless otherwise specified. The components of the optical filters 1b to 1f that are the same as or correspond to the components of the optical filter 1a are denoted by the same reference numerals, and detailed description thereof will be omitted. The description regarding the optical filter 1a also applies to the optical filters 1b to 1f unless there is a technical contradiction.

As shown in FIG. 1B, an optical filter 1b according to another example of the present invention includes a UV-IR absorption layer 10, and a pair of antireflection films 30 disposed on both surfaces thereof. The anti-reflection film 30 is a film formed so as to form an interface between the optical filter 1b and air and for reducing reflection of light in a visible light region. The antireflection film 30 is a film formed of a dielectric such as a resin, an oxide, and a fluoride, for example. The antireflection film 30 may be a multilayer film formed by laminating two or more types of dielectrics having different refractive indexes. In particular, the antireflection film 30 may be a dielectric multilayer film made of a low refractive index material such as SiO ₂ and a high refractive index material such as TiO ₂ or Ta ₂ O ₅ . In this case, Fresnel reflection at the interface between the optical filter 1b and air is reduced, and the amount of light in the visible light region of the optical filter 1b can be increased. Note that a resin layer containing a silane coupling agent may be formed between the UV-IR absorption layer 10 and the antireflection film 30 in order to improve the adhesion of the antireflection film 30. The antireflection film 30 may be disposed on both main surfaces of the UV-IR absorption layer 10, or may be disposed on only one of the main surfaces. The optical filter 1b can contribute to reducing the height of the imaging device and the optical system, and can increase the amount of light in the visible light region as compared with the optical filter 1a.

As shown in FIG. 1C, an optical filter 1c according to another example of the present invention includes a UV-IR absorption layer 10 and a reflection film 40 that reflects infrared light and / or ultraviolet light disposed on one main surface thereof. Have. The reflection film 40 is, for example, a film formed by evaporating a metal such as aluminum, or a dielectric multilayer film in which layers made of a high-refractive-index material and layers made of a low-refractive-index material are alternately stacked. is there. As the high refractive index material _{TiO 2, ZrO 2, Ta 2} O 5, Nb 2 O 5, ZnO, and In ₂ O ₃ material having a refractive index of 1.7 to 2.5, such as are used. The low refractive index _{material, SiO 2, Al 2 O 3} , and a material having a refractive index of 1.2 to 1.6 of MgF ₂ or the like is used. The method for forming the dielectric multilayer film is, for example, a chemical vapor deposition (CVD) method, a sputtering method, or a vacuum evaporation method. Further, such a reflective film may be formed so as to form both main surfaces of the optical filter (not shown). When the reflection films are formed on both main surfaces of the optical filter, the stress is balanced on both the front and back surfaces of the optical filter, and there is an advantage that the optical filter is hardly warped.

  As shown in FIG. 1D, an optical filter 1d according to another example of the present invention includes a transparent dielectric substrate 20, and a UV-IR absorption layer 10 formed on one main surface of the transparent dielectric substrate 20. ing. The transparent dielectric substrate 20 is not particularly limited as long as it is a dielectric substrate having a high average transmittance (e.g., 80% or more) at 450 nm to 600 nm. In some cases, the transparent dielectric substrate 20 may have an absorbing ability in an ultraviolet region or an infrared region.

  The transparent dielectric substrate 20 is made of, for example, glass or resin. When the transparent dielectric substrate 20 is made of glass, the glass contains, for example, borosilicate glass such as D263Tec, soda-lime glass (blue plate), white plate glass such as B270, non-alkali glass, or copper. Infrared absorbing glass such as phosphate glass containing copper or fluorophosphate glass containing copper. When the transparent dielectric substrate 20 is an infrared absorbing glass such as a copper-containing phosphate glass or a copper-containing fluorophosphate glass, the infrared absorption performance and UV of the transparent dielectric substrate 20 have -The infrared absorption performance required for the optical filter 1d can be realized by a combination with the infrared absorption performance of the IR absorption layer 10. Therefore, the level of infrared absorption performance required for the UV-IR absorption layer 10 can be reduced. Such infrared-absorbing glass is, for example, BG-60, BG-61, BG-62, BG-63, or BG-67 manufactured by Schott, 500EXL manufactured by NEC Corporation, or HOYA. CM5000, CM500, C5000 or C500S manufactured by the company. Further, the infrared absorbing glass may have an ultraviolet absorbing property.

  The transparent dielectric substrate 20 may be a transparent crystalline substrate such as magnesium oxide, sapphire, or quartz. For example, sapphire has a high hardness and is therefore not easily scratched. For this reason, the plate-shaped sapphire may be disposed as a scratch-resistant protective material (protection filter) on the front surface of a camera module or a lens provided in a mobile terminal such as a smartphone and a mobile phone. By forming the UV-IR absorption layer 10 on such a plate-like sapphire, it is possible to protect the camera module and the lens and to shield ultraviolet rays or infrared rays. This eliminates the need to dispose an optical filter having an ultraviolet or infrared shielding property around a solid-state imaging device such as a CCD or CMOS or inside a camera module. Therefore, if the UV-IR absorption layer 10 is formed on a plate-like sapphire, it can contribute to a reduction in the height of the camera module.

  When the transparent dielectric substrate 20 is made of a resin, the resin may be, for example, a (poly) olefin resin, a polyimide resin, a polyvinyl butyral resin, a polycarbonate resin, a polyamide resin, a polysulfone resin, a polyethersulfone resin, or a polyamideimide resin. , (Modified) acrylic resin, epoxy resin, or silicone resin.

  When the transparent dielectric substrate 20 is a glass substrate, a resin layer containing a silane coupling agent is used to improve the adhesion between the transparent dielectric substrate 20 and the UV-IR absorption layer 10. -It may be formed between the IR absorption layer 10.

  As shown in FIG. 1E, an optical filter 1e according to another example of the present invention has a UV-IR absorption layer 10 formed on both main surfaces of a transparent dielectric substrate 20. Thus, the optical filter 1e can exhibit the above-described optical performances (i) to (iv) not by one UV-IR absorption layer 10 but by two UV-IR absorption layers 10. The thickness of the UV-IR absorption layer 10 on both main surfaces of the transparent dielectric substrate 20 may be the same or different. That is, the UV is applied to both main surfaces of the transparent dielectric substrate 20 such that the thickness of the UV-IR absorption layer 10 necessary for the optical filter 1e to obtain desired optical characteristics is evenly or unevenly distributed. -The IR absorption layer 10 is formed. Thereby, the thickness of each UV-IR absorption layer 10 formed on both main surfaces of the transparent dielectric substrate 20 is relatively small. As a result, the internal pressure of the coating film is low, and the occurrence of cracks can be prevented. Further, the time for applying the liquid optical filter composition can be reduced, and the time for curing the coating film of the optical filter composition can be reduced. When the transparent dielectric substrate 20 is thin, if the UV-IR absorption layer 10 is formed only on one main surface of the transparent dielectric substrate 20, the UV-IR absorption layer 10 is formed from the optical filter composition. The optical filter may warp due to the stress accompanying the shrinkage. However, since the UV-IR absorption layer 10 is formed on both main surfaces of the transparent dielectric substrate 20, even when the transparent dielectric substrate 20 is thin, warpage is suppressed in the optical filter 1e. Also in this case, in order to improve the adhesion between the transparent dielectric substrate 20 and the UV-IR absorption layer 10, a resin layer containing a silane coupling agent is provided between the transparent dielectric substrate 20 and the UV-IR absorption layer 10. May be formed.

  As shown in FIG. 1F, an optical filter 1f according to another example of the present invention includes an antireflection film 30. The antireflection film 30 is formed so as to form an interface between the optical filter 1f and air. In the optical filter 1f, the antireflection film 30 is disposed on both main surfaces of the optical filter 1f, but may be disposed on only one main surface. In this case, the amount of light in the visible light region of the optical filter 1f can be increased.

  Each of the optical filters 1a to 1f may be modified to include an infrared absorption film (not shown) separately from the UV-IR absorption layer 10, as necessary. The infrared absorbing film contains, for example, an organic infrared absorbing agent such as a cyanine-based, phthalocyanine-based, squarylium-based, diimmonium-based, or azo-based infrared absorbing agent or an infrared absorbing agent formed of a metal complex. The infrared absorbing film contains, for example, one or more infrared absorbing agents selected from these infrared absorbing agents. This organic infrared absorbent has a small wavelength range (absorption band) of light that can be absorbed and is suitable for absorbing light in a specific range of wavelength.

  Each of the optical filters 1a to 1f may be modified to include an ultraviolet absorbing film (not shown) separately from the UV-IR absorbing layer 10, as necessary. The ultraviolet absorbing film contains, for example, a benzophenone-based, triazine-based, indole-based, merocyanine-based, or oxazole-based ultraviolet absorber. The ultraviolet absorbing film contains, for example, one or more ultraviolet absorbing agents selected from these ultraviolet absorbing agents. These ultraviolet absorbers may include, for example, those that absorb ultraviolet light in the vicinity of 300 nm to 340 nm, emit light (fluorescence) having a longer wavelength than the absorbed wavelength, and function as a fluorescent agent or a fluorescent whitening agent. The ultraviolet absorbing film can reduce the incidence of ultraviolet light that causes deterioration of a material used for an optical filter such as a resin.

  The above-mentioned infrared absorber or ultraviolet absorber may be previously contained in the transparent dielectric substrate 20 made of resin. The infrared absorbing film or the ultraviolet absorbing film can be formed, for example, by forming a resin containing an infrared absorbing agent or an ultraviolet absorbing agent. In this case, the resin needs to be capable of appropriately dissolving or dispersing the infrared absorber or the ultraviolet absorber and to be transparent. Such resins include (poly) olefin resins, polyimide resins, polyvinyl butyral resins, polycarbonate resins, polyamide resins, polysulfone resins, polyethersulfone resins, polyamideimide resins, (modified) acrylic resins, epoxy resins, and silicone resins. Can be exemplified.

  The optical filters 1a to 1f are arranged, for example, in front of a solid-state imaging device such as a CCD or a CMOS (closer to a subject) in order to make the spectral sensitivity of the imaging device close to human visibility.

  Further, as shown in FIG. 2, for example, a camera module 100 using the optical filter 1d can be provided. The camera module 100 includes, for example, a lens system 2, a low-pass filter 3, a solid-state imaging device 4, a circuit board 5, an optical filter support housing 7, and an optical system housing 8 in addition to the optical filter 1d. The peripheral edge of the optical filter 1d is fitted in, for example, an annular concave portion that is in contact with an opening formed in the center of the optical filter support housing 7. The optical filter support case 7 is fixed to the optical system case 8. Inside the optical system housing 8, the lens system 2, the low-pass filter 3, and the solid-state imaging device 4 are arranged in this order along the optical axis. The solid-state imaging device 4 is, for example, a CCD or a CMOS. The light from the subject is collected by the lens system 2 after the ultraviolet and infrared rays are cut off by the optical filter 1d, and further passes through the low-pass filter 3 to enter the solid-state imaging device 4. The electric signal generated by the solid-state imaging device 4 is sent to the outside of the camera module 100 by the circuit board 5.

  In the camera module 100, the optical filter 1d also functions as a cover (protect filter) for protecting the lens system 2. In this case, a sapphire substrate is preferably used as the transparent dielectric substrate 20 in the optical filter 1d. Since the sapphire substrate has high scratch resistance, for example, it is desirable that the sapphire substrate is disposed outside (on the side opposite to the solid-state imaging device 4 side). Accordingly, the optical filter 1d has high scratch resistance against external contact and the like, absorbs ultraviolet rays and infrared rays, and has a low haze of 5% or less. The optical filter 1d desirably has the above-described optical performances (i) to (iv), and more desirably further has the optical performances (v) to (vii). Accordingly, it is not necessary to dispose an optical filter for cutting infrared rays or ultraviolet rays near the solid-state imaging device 4, and the camera module 100 can be easily lowered. Note that the camera module 100 shown in FIG. 2 is a schematic diagram for exemplifying the arrangement and the like of each component, and explains an aspect in which the optical filter 1d is used as a protection filter. As long as the optical filter 1d functions as a protection filter, the camera module using the optical filter 1d is not limited to the one shown in FIG. 2, and the low-pass filter 3 may be omitted as necessary. Other filters may be provided.

  The present invention will be described in more detail with reference to examples. Note that the present invention is not limited to the following embodiments.

<Example 1>
4.500 g of copper acetate monohydrate and 240 g of tetrahydrofuran (THF) were mixed and stirred for 3 hours to obtain a copper acetate solution. Next, 1.646 g of Plysurf A208N (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), which is a phosphoric ester compound, was added to the obtained copper acetate solution, followed by stirring for 30 minutes to obtain a solution A. 40 g of THF was added to 0.706 g of phenylphosphonic acid, followed by stirring for 30 minutes to obtain a B-1 solution. To 4.230 g of 4-bromophenylphosphonic acid was added 40 g of THF, and the mixture was stirred for 30 minutes to obtain a B-2 solution. Next, the B-1 solution and the B-2 solution are mixed and stirred for 1 minute, and 8.664 g of methyltriethoxysilane (MTES: manufactured by Shin-Etsu Chemical Co., Ltd.) and tetraethoxysilane (TEOS: special grade manufactured by Kishida Chemical Co., Ltd.) 2.840 g was added to this mixture, and the mixture was further stirred for 1 minute to obtain a solution B. Solution B was added to Solution A while stirring Solution A, and the mixture was stirred at room temperature for 1 minute. Next, 140 g of toluene was added to this solution, followed by stirring at room temperature for 1 minute to obtain a liquid C. The solution C was placed in a flask and heated with an oil bath (manufactured by Tokyo Rika Kikai Co., Ltd., model: OSB-2100), and the solvent was removed by a rotary evaporator (manufactured by Tokyo Rika Kiki Co., model: N-1110SF). went. The set temperature of the oil bath was adjusted to 105 ° C. Thereafter, the solution D according to Example 1 after the solvent removal treatment was taken out of the flask. The solvent removal treatment was performed so that the viscosity of the solution D was reduced to some extent without completely removing the solvent in the solvent removal treatment. Liquid D, which is a dispersion of fine particles of copper phenyl phosphonate (UV-IR absorber), was transparent, and the fine particles were well dispersed in liquid D. The obtained solution D was 107.06 g. Table 1 shows the amount of toluene added to obtain the solution D, the mass of the obtained solution D, and the concentration of copper ions in the solution D.

  4.500 g of copper acetate monohydrate and 240 g of THF were mixed and stirred for 3 hours to obtain a copper acetate solution. Next, 2.572 g of Plysurf A208N, which is a phosphate compound, was added to the obtained copper acetate solution, followed by stirring for 30 minutes to obtain a solution E. In addition, THF (40 g) was added to 2.886 g of n-butylphosphonic acid and stirred for 30 minutes to obtain a solution F. The solution F was added to the solution E while stirring the solution E, and the mixture was stirred at room temperature for 1 minute. Next, 84 g of toluene was added to this solution, followed by stirring at room temperature for 1 minute to obtain a solution G. The solution G was placed in a flask, and the mixture was desolvated by a rotary evaporator while being heated in an oil bath. The set temperature of the oil bath was adjusted to 105 ° C. Thereafter, the H solution according to Example 1 after the solvent removal treatment was taken out of the flask. The solvent removal treatment was performed so that the viscosity of the solution H became a predetermined viscosity without completely removing the solvent in the solvent removal treatment. The liquid H, which is a dispersion of fine particles of copper butylphosphonate (UV-IR absorber), was transparent, and the fine particles were well dispersed in the liquid H. The obtained liquid H was 68.12 g. Table 2 shows the amount of toluene added to obtain the H solution, the mass of the obtained H solution, and the concentration of copper ions in the H solution.

  To Liquid D, 10.69 g of a silicone resin (product name: KR-300, manufactured by Shin-Etsu Chemical Co., Ltd.) was added, and the mixture was stirred for 30 minutes to obtain Liquid I. 27.25 g of the H solution corresponding to 40% by mass of the total amount of the H solution was added to the I solution and stirred for 30 minutes to obtain a composition for an optical filter according to Example 1. Table 3 shows the addition amounts of the solution D, the solution H, and the silicone resin in the optical filter composition according to Example 1.

  0.1 g of a surface antifouling coating agent (manufactured by Daikin Industries, product name: Optool DSX, concentration of active ingredient: 20% by mass) and 19.9 g of Novec 7100 (manufactured by 3M, component: hydrofluoroether) were mixed. After stirring for 5 minutes, a fluorinating agent (concentration of active ingredient: 0.1% by mass) was prepared. This fluorinated agent was applied to a transparent glass substrate (manufactured by SCHOTT, product name: D263 Teco) made of borosilicate glass having dimensions of 76 mm x 76 mm x 0.21 mm at a rotation speed of 3000 rpm (revolutions per minute). Spin coated. Thereafter, the transparent glass substrate was left at room temperature for 24 hours to dry the coating film of the fluorinating agent, thereby obtaining a glass substrate which had been subjected to a fluorine treatment (easy peeling treatment).

  Using the dispenser, the composition for an optical filter according to Example 1 was applied to a square area having a center of about 30 mm × 30 mm of the main surface of the glass substrate subjected to the fluorine treatment to form a coating film. A frame having a 30 mm × 30 mm square hole as a center and having a thickness of 5 mm was attached to a glass substrate, and the composition for an optical filter according to Example 1 was applied inside the frame. Next, the transparent glass substrate having the undried coating film was placed in an oven and subjected to a heat treatment at 45 ° C. for 2 hours and further at 85 ° C. for 6 hours to cure the coating film. Thereafter, the glass substrate having the coating film was placed in a thermo-hygrostat set at a temperature of 85 ° C. and a relative humidity of 85% for 2 hours to perform a humidification treatment. Thereafter, a layer formed by curing the coating film of the composition for an optical filter from the glass substrate was peeled off, and an optical filter according to Example 1 was produced.

<Examples 2 to 15 and Comparative Example 1>
The procedure was performed except that the preparation conditions for the solution D were changed so that the amount of toluene added to obtain the solution D, the mass of the obtained solution D, and the concentration of copper ions in the solution D were as shown in Table 1. In the same manner as in Example 1, D solution according to Examples 2 to 15 and D solution according to Comparative example 1 were prepared. Except that the preparation conditions of the H solution were changed so that the amount of toluene added to obtain the H solution, the mass of the obtained H solution, and the concentration of copper ions in the H solution were as shown in Table 2, In the same manner as in Example 1, H solutions according to Examples 2 to 15 and Comparative Example 1 were prepared. The compositions for optical filters according to Examples 2 to 15 and Comparative Example 1 were prepared in the same manner as in Example 1 except that the addition amounts of the D liquid, the H liquid, and the silicone resin were adjusted as shown in Table 3. did. Furthermore, in the same manner as in Example 1 except that the optical filter compositions according to Examples 2 to 15 and Comparative Example 1 were used instead of the optical filter compositions according to Example 1, Optical filters according to 2 to 15 and Comparative Example 1 were produced.

<Example 16>
4.500 g of copper acetate monohydrate and 240 g of tetrahydrofuran (THF) were mixed and stirred for 3 hours to obtain a copper acetate solution. Next, 1.646 g of Plysurf A208N (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), which is a phosphoric ester compound, was added to the obtained copper acetate solution, followed by stirring for 30 minutes to obtain a solution A. 40 g of THF was added to 0.769 g of p-toluenesulfonic acid and stirred for 30 minutes to obtain a B-1 solution. To 4.230 g of 4-bromobenzenesulfonic acid was added 40 g of THF, and the mixture was stirred for 30 minutes to obtain a B-2 solution. Next, the B-1 solution and the B-2 solution are mixed and stirred for 1 minute, and 8.664 g of methyltriethoxysilane (MTES: manufactured by Shin-Etsu Chemical Co., Ltd.) and tetraethoxysilane (TEOS: special grade manufactured by Kishida Chemical Co., Ltd.) 2.840 g was added to this mixture, and the mixture was further stirred for 1 minute to obtain a solution B. Solution B was added to Solution A while stirring Solution A, and the mixture was stirred at room temperature for 1 minute. Next, 140 g of toluene was added to this solution, followed by stirring at room temperature for 1 minute to obtain a liquid C. The solution C was placed in a flask and heated with an oil bath (manufactured by Tokyo Rika Kikai Co., Ltd., model: OSB-2100), and the solvent was removed by a rotary evaporator (manufactured by Tokyo Rika Kiki Co., model: N-1110SF). went. The set temperature of the oil bath was adjusted to 105 ° C. Thereafter, the solution D according to Example 1 after the solvent removal treatment was taken out of the flask. The solvent removal treatment was performed so that the viscosity of the solution D was reduced to some extent without completely removing the solvent in the solvent removal treatment. Liquid D, which is a dispersion of fine particles of copper phenyl sulfonate (UV-IR absorber), was transparent, and the fine particles were well dispersed in Liquid D. The obtained solution D was 107.12 g. Table 1 shows the amount of toluene added to obtain the solution D, the mass of the obtained solution D, and the concentration of copper ions in the solution D.

  4.500 g of copper acetate monohydrate and 240 g of THF were mixed and stirred for 3 hours to obtain a copper acetate solution. Next, 2.572 g of Plysurf A208N, which is a phosphate compound, was added to the obtained copper acetate solution, followed by stirring for 30 minutes to obtain a solution E. In addition, 40 g of THF was added to 2.886 g of 1-butanesulfonic acid, followed by stirring for 30 minutes to obtain a solution F. The solution F was added to the solution E while stirring the solution E, and the mixture was stirred at room temperature for 1 minute. Next, 84 g of toluene was added to this solution, followed by stirring at room temperature for 1 minute to obtain a solution G. The solution G was placed in a flask, and the mixture was desolvated by a rotary evaporator while being heated in an oil bath. The set temperature of the oil bath was adjusted to 105 ° C. Thereafter, the H solution according to Example 1 after the solvent removal treatment was taken out of the flask. The solvent removal treatment was performed so that the viscosity of the solution H became a predetermined viscosity without completely removing the solvent in the solvent removal treatment. Liquid H, which is a dispersion of fine particles of copper butanesulfonate (UV-IR absorber), was transparent, and fine particles were well dispersed in liquid H. The obtained liquid H was 68.12 g. Table 2 shows the amount of toluene added to obtain the H solution, the mass of the obtained H solution, and the concentration of copper ions in the H solution.

  To Liquid D, 10.69 g of a silicone resin (product name: KR-300, manufactured by Shin-Etsu Chemical Co., Ltd.) was added, and the mixture was stirred for 30 minutes to obtain Liquid I. 27.25 g of the H solution corresponding to 40% by mass of the total amount of the H solution was added to the I solution and stirred for 30 minutes to obtain a composition for an optical filter according to Example 1. Table 3 shows the addition amounts of the D solution, the H solution, and the silicone resin in the optical filter composition according to Example 16.

  An optical filter according to Example 16 was produced in the same manner as in Example 1, except that the composition for an optical filter according to Example 16 was used instead of the composition for an optical filter according to Example 1.

(Measurement of viscosity of composition for optical filter)
Using a vibration type viscometer (produced by SECONIC, probe: PR-10L, controller: VM-10A), the viscosity at 22 to 23 ° C of the composition for an optical filter according to each example and comparative example 1 was measured. . Table 3 shows the results. As shown in Table 3, the viscosity at 22 to 23 ° C. of the optical filter composition according to each example was included in the range of 1 to 200 mPa · s, whereas the optical filter composition according to Comparative Example 1 was used. Had a viscosity of 330 mPa · s at 22 to 23 ° C.

(Measurement of solid content of optical filter composition and calculation of solid content ratio)
An aluminum sheet (manufactured by Sumitomo Aluminum Foil Co., Ltd., thickness: 12 μm) was spread on the bottom of a stainless steel tray, and each example and comparative example 1 was placed on the aluminum sheet so that the thickness after curing became 100 to 300 μm. Was applied to prepare an uncured sample. The sample before curing was placed in an oven whose internal temperature was maintained at 45 ° C., and the internal temperature of the oven was maintained at 45 ° C. for 2 hours. Thereafter, the temperature inside the oven was further raised to 85 ° C. over 30 minutes, and the temperature inside the oven was kept at 85 ° C. for 6 hours. After that, the oven was turned off and allowed to cool naturally, and the sample was taken out of the oven after the temperature inside the oven had dropped to about room temperature. Next, the sample is put into a thermo-hygrostat, the inside of the thermo-hygrostat is changed to an environment of a temperature of 85 ° C. and a relative humidity of 85% over 45 minutes, and the thermo-hygrostat is kept in the environment for 2 hours. Kept. Then, the temperature and humidity of the environment of the thermo-hygrostat were sufficiently reduced over 45 minutes, and then the sample was taken out of the thermo-hygrostat. The sample was sufficiently dry and cured. The mass Wb of the cured sample was measured, and the measurement result was determined as the mass of the solid content. From the mass Wb of the sample after curing and the mass Wa of the sample before curing, the solid content ratio (Wb / Wa × 100) in the composition for an optical filter according to each of Examples and Comparative Example 1 was determined. Table 3 shows the results.

(Measurement of optical filter thickness)
Using a laser displacement meter (manufactured by Keyence Corporation, product name: LK-H008), the distance between the front and back surfaces of the optical filter according to each example and comparative example 1 was measured, and the optical filter according to each example and comparative example 1 was measured. The thickness of the filter was calculated. Table 4 shows the results.

(Haze measurement)
Using a haze meter (manufactured by Murakami Color Research Laboratory Co., Ltd., product name: HM-65L2), the haze of the optical filter according to each example and comparative example 1 was measured in accordance with JIS K 7136: 2000.
Table 4 shows the results.

(Measurement of spectral transmittance)
Using an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, product name: V-670), light having a wavelength of 300 nm to 1200 nm was incident on the optical filter according to each example and comparative example 1 at an incident angle of 0 °. The transmission spectrum at that time was measured. From this transmittance spectrum, the average transmittance at a wavelength of 450 to 600 nm, the average transmittance at a wavelength of 300 to 350 nm, the IR cutoff wavelength, and the UV cutoff wavelength were determined for the optical filters according to the examples and comparative example 1. Was. Table 4 shows the results. FIGS. 3 to 8 show transmittance spectra according to Examples 1, 4, 13, 14, and 15 and Comparative Example 1, respectively.

  In the optical filter according to each example, the average transmittance at a wavelength of 450 nm to 600 nm was 78% or more, and the average transmittance at a wavelength of 300 nm to 350 nm was less than 0.2%. In the optical filters according to the respective examples, the IR cutoff wavelength was in the range of 610 nm to 680 nm, and the UV cutoff wavelength was in the range of 380 nm to 430 nm. From these results, the optical filters according to the examples had good transmittance characteristics. In addition, the haze of the optical filter according to each example was 5% or less. For this reason, the optical filters according to the examples had good optical characteristics from the viewpoint of haze in addition to the transmittance characteristics.

  In the optical filter according to Comparative Example 1, the average transmittance at a wavelength of 450 nm to 600 nm was 81.9%, and the average transmittance at a wavelength of 300 nm to 350 nm was less than 0.2%. Further, in the optical filter according to each example, the IR cutoff wavelength was 631 nm, and the UV cutoff wavelength was 407 nm. From these results, it was found that the optical filter according to Comparative Example 1 had good transmittance characteristics to some extent. On the other hand, the haze of the optical filter according to Comparative Example 1 was 8.4%, greatly exceeding 5%. For this reason, it was difficult to say that the optical filter according to Comparative Example 1 had desirable optical characteristics from the viewpoint of haze.

Claims (5)

With a UV-IR absorption layer containing a UV-IR absorber capable of absorbing ultraviolet light and infrared light formed by phosphonic acid and copper ions,
The phosphonic acid includes a phosphonic acid having a phenyl group or a halogenated phenyl group in which at least one hydrogen atom in the phenyl group is substituted with a halogen atom,
Having a haze of 5% or less,
Optical filter.   The optical filter according to claim 1, wherein the phosphonic acid further includes a phosphonic acid having an alkyl group. When light having a wavelength of 300 nm to 1200 nm is incident at an incident angle of 0 °,
Having a spectral transmittance of 1% or less at a wavelength of 300 nm to 350 nm,
Having an average transmittance of 78% or more at a wavelength of 450 nm to 600 nm,
Having a spectral transmittance of 5% or less at a wavelength of 750 nm to 1080 nm,
The optical filter according to claim 1. When light having a wavelength of 300 nm to 1200 nm is incident at an incident angle of 0 °,
An IR cutoff wavelength at which the spectral transmittance shows 50% at a wavelength of 600 nm to 750 nm exists in a range of 610 nm to 680 nm,
A UV cutoff wavelength having a spectral transmittance of 50% at a wavelength of 350 nm to 450 nm exists in a range of 380 nm to 430 nm.
The optical filter according to claim 3.   The optical filter according to claim 1, wherein the UV-IR absorption layer has a thickness of 100 to 300 μm.

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