JP6686222B2 - Composition for optical filter and method for producing 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 CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor), various optical filters are arranged in front of the solid-state imaging device in order to obtain an image having good color reproducibility. Has been done. Generally, a solid-state image sensor has spectral sensitivity in a wide wavelength range from the ultraviolet region to the infrared region. On the other hand, human visibility exists only in the visible light region. Therefore, in order to bring the spectral sensitivity of the solid-state image sensor in the image pickup device closer to human visual sensitivity, a technique is known in which an optical filter that blocks infrared rays or ultraviolet rays is arranged in front of the solid-state image sensor.

  For example, Patent Document 1 includes a UV-IR absorption layer capable of absorbing infrared rays and ultraviolet rays, and has a predetermined transmission characteristic when light with a wavelength of 300 nm to 1200 nm is incident at incident angles of 0 ° and 40 °. An optical filter having 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

  The optical filter described in Patent Document 1 has a desired characteristic with respect to transmittance, but Patent Document 1 does not consider the haze of the optical filter at all. Therefore, the present invention provides an optical filter composition which contains a UV-IR absorber and is advantageous for producing an optical filter having a desired haze. The present invention also provides a method for producing an optical filter using the composition for an optical filter.

The present invention is
Containing at least one acid of phosphonic acid and sulfonic acid, phosphoric acid ester, and alkoxysilane or a hydrolyzate of alkoxysilane,
Has a viscosity of 1 to 200 mPa · s at 22 to 23 ° C.,
Contains 3 to 17 mass% solids,
Provided is a composition for an optical filter.

Further, the present invention is
There is provided a method of making an optical filter comprising curing the composition described above.

  The above composition for an optical filter is advantageous for producing an optical filter having a desired haze while containing a UV-IR absorber.

FIG. 1A is a sectional view showing an example of the optical filter of the present invention. FIG. 1B is a cross-sectional view showing 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 equipped with 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 the thirteenth embodiment. FIG. 6 is a transmittance spectrum of the optical filter according to the fourteenth embodiment. FIG. 7 is a transmittance spectrum of the optical filter according to the fifteenth embodiment. 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. In addition, 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 containing a UV-IR absorber formed by phosphonic acid and copper ions may have desired properties regarding 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. It was The haze corresponds to the percentage of the diffuse transmittance with respect to the total light transmittance. For example, in Japanese Industrial Standard (JIS) K 7136: 2000, out of the transmitted light passing through the test piece, forward scattering causes the incident light to reach 0. It is defined as the percentage of transmitted light that deviates from 044 rad (2.5 °) or more. In the present specification, the definition of haze follows JIS K 7136: 2000, and the haze is measured according to JIS K 7136: 2000.

  If the optical filter has desirable properties in terms of transmittance but has a high haze, placing the optical filter in front of the solid-state image sensor of the image pickup device may reduce the image quality of the image obtained by the image pickup device. . For example, problems such as color unevenness, bleeding, flare, and decrease in brightness may occur in the image. Therefore, the inventors of the present invention have repeatedly studied day and night about a technique for keeping the haze low in an optical filter provided with a UV-IR absorption layer containing a UV-IR absorber formed by phosphonic acid and copper ions. As a result, the inventors have found that the dispersion state of the UV-IR absorber formed by the phosphonic acid and the copper ion in the composition for producing the optical filter may influence 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 realizing low haze. It has been newly found that Furthermore, based on this newly discovered finding, it was also 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. It was Therefore, the present inventors repeated 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 1 a includes a UV-IR absorption layer 10. The UV-IR absorption layer 10 contains a UV-IR absorber capable of absorbing ultraviolet rays and infrared rays formed by at least one acid of phosphonic acid and sulfonic acid and copper ions. The optical filter 1a has a haze of 5% or less. Therefore, a high-quality image can be obtained by the image pickup device in which the optical filter 1a is incorporated.

  The optical filter 1a desirably has a haze of 4% or less. This makes it possible to more reliably obtain a high-quality image with the image pickup apparatus incorporating the optical filter 1a. The optical filter 1a desirably has a haze of 1% or less. As a result, a higher quality image can be obtained by the image pickup device having the optical filter 1a incorporated therein.

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 °. Since the optical filter 1a exhibits the following optical performance together with a haze of 5% or less, a high-quality image can be obtained in an image pickup device incorporating the optical filter 1a.
(I) Average transmittance of 78% or more at wavelengths of 450 nm to 600 nm (ii) Spectral transmittance of 1% or less at wavelengths of 300 nm to 350 nm (iii) Spectral transmittance and wavelength that decrease with increasing wavelength at wavelengths of 600 nm to 750 nm First IR cutoff wavelength existing in the range of 610 nm to 680 nm (iv) Spectral transmittance increasing with an increase in wavelength at a wavelength of 350 nm to 450 nm, and first UV cutoff wavelength existing in the range of 380 nm to 430 nm.

  In the present specification, the “spectral transmittance” is the transmittance when incident light having a specific wavelength is incident on an object such as a sample, and the “average transmittance” is the spectral transmittance within a predetermined wavelength range. In this specification, the “transmittance spectrum” refers to the spectral transmittance at each wavelength within a predetermined wavelength range arranged in order of wavelength.

  In the present specification, the “IR cutoff wavelength” indicates a spectral transmittance of 50% in a wavelength range of 600 nm or more when light having a wavelength of 300 nm to 1200 nm is incident on the 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 °. In addition, the “UV cutoff wavelength” is a wavelength showing a spectral transmittance of 50% in a wavelength range of 450 nm or less when light having a wavelength of 300 nm to 1200 nm is incident on the 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) above, the optical filter 1a has a large amount of transmission of light having a wavelength of 450 nm to 600 nm, and light having wavelengths of 300 nm to 400 nm and 650 nm or more. Can be effectively cut. Therefore, the transmittance spectrum of the optical filter 1a is suitable for human visibility. Moreover, even if the optical filter 1a does not include a layer other than the UV-IR absorption layer 10, the optical performances (i) to (iv) described above can be exhibited, and a haze of 5% or less can be realized.

  Regarding the above (i), 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 the above (ii), 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 showing a spectral transmittance of 50%) is preferably in the range of wavelength 610 nm to 660 nm, more preferably in the range of wavelength 610 nm to 650 nm. Exists in. 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%) is preferably in the range of 390 nm to 430 nm, and more preferably in the range of 400 nm to 425 nm. Exists in. 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 °. As a result, the optical filter 1a can effectively cut 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 with a wavelength of 300 nm to 1200 nm is incident at an incident angle of 0 °. Thereby, infrared rays having a relatively long wavelength (wavelength 1000 to 1100 nm) can be cut. Conventionally, in order to cut off light of this wavelength, a light reflecting film made 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 laminated dielectrics in the light reflection film can be reduced and The cost required for formation can be reduced.
(Vi) Spectral transmittance of 10% or less at a wavelength of 1000 to 1100 nm

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

  The phosphonic acid forming the UV-IR absorber in the UV-IR absorbing layer 10 includes, for example, a primary phosphonic acid having an aryl group. As a result, the optical filter 1a is likely to exhibit the above 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, Alternatively, it is 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 a halogenated phenyl group in a part thereof. In this case, the optical filter 1a is more likely to exhibit the optical performances (i) to (iv) more reliably.

  The phosphonic acid forming the UV-IR absorber in the UV-IR absorbing layer 10 desirably further comprises a secondary phosphonic acid having an alkyl group. In the secondary phosphonic acid, the alkyl group is attached to the phosphorus atom. The alkyl group of the secondary 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 the phenyl group is substituted with a halogen atom.

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

  The sulfonic acid forming the UV-IR absorber in the UV-IR absorbing layer 10 includes, for example, a first sulfonic acid having an aryl group. As a result, the optical filter 1a is likely to exhibit the above 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. . Alternatively, it is 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 absorbing layer 10 desirably further comprises a secondary 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 secondary sulfonic acid may have an aromatic substituent.

  The UV-IR absorption layer 10 desirably further includes a phosphoric acid ester in which the UV-IR absorber is dispersed, and a matrix resin.

The phosphoric acid ester contained in the UV-IR absorbing layer 10 is not particularly limited as long as it can appropriately disperse the UV-IR absorbing agent. For example, the phosphoric acid diester represented by the following formula (c1) and the following formula (c1) It contains 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 kinds of functional groups from each other.

  The phosphate ester is not particularly limited, and for example, Plysurf A208N: polyoxyethylene alkyl (C12, C13) ether phosphate ester, Plysurf A208F: polyoxyethylene alkyl (C8) ether phosphate ester, 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, Prisurf A215C: polyoxyethylene tridecyl ether phosphate ester. All of these are products manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. The phosphoric acid ester is NIKKOL DDP-2: polyoxyethylene alkyl ether phosphoric acid ester, NIKKOL DDP-4: polyoxyethylene alkyl ether phosphoric acid ester, or NIKKOL DDP-6: polyoxyethylene alkyl ether phosphoric acid ester. possible. All of these are products manufactured 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 heat-cured or UV-cured. Further, when a resin layer having a thickness of 0.1 mm is formed from the resin as the matrix resin, the transmittance of the resin layer for the wavelength of 350 nm to 900 nm is, for example, 70% or more, preferably 75% or more, and more preferably Can use a resin of 80% or more. 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 the above characteristics are satisfied, but examples thereof include (poly) olefin resin, polyimide resin, polyvinyl butyral resin, polycarbonate resin, polyamide resin, polysulfone resin and polyether. It is a sulfone resin, a polyamide-imide resin, a (modified) acrylic resin, an epoxy resin, or a 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), as the thickness of the UV-IR absorption layer 10 increases, cracks easily occur due to curing shrinkage during the manufacturing process of the optical filter 1a. When the matrix resin is a silicone resin containing an aryl group, the UV-IR absorption layer 10 tends to have good crack resistance. Further, when a silicone resin containing an aryl group is used, the UV-IR absorber formed by at least one of the above phosphonic acid and sulfonic acid and copper ions is less likely to aggregate. Furthermore, 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 phosphorus compound represented by the formula (c1) or the formula (c2). It is desirable to have a linear organic functional group having flexibility 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 acid ester having a linear organic functional group such as an oxyalkyl group, UV- This is because the IR absorber is less likely to aggregate and can provide the UV-IR absorbing 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 contains a hydrolyzed polycondensation product of an alkoxysilane monomer, if necessary. When the optical filter 1a contains a hydrolysis-condensation polymer of an alkoxysilane monomer, the optical filter 1a has good moisture resistance due to the siloxane bond (-Si-O-Si-) of the hydrolysis-condensation polymer of the alkoxysilane monomer. . In addition, the optical filter 1a has good heat resistance. This is because the siloxane bond has higher bond energy and is more chemically stable than bonds such as —C—C— bond and —C—O— bond, 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 optical filters contains at least one acid of phosphonic acid and sulfonic acid, and copper ions. In addition, the composition for an optical filter is such that when the coating film of this composition is cured to form a layer having a thickness of 100 to 300 μm, this layer can absorb ultraviolet rays and infrared rays, and this layer Has a haze of 5% or less (preferably 4% or less). It should be noted that such properties may be exhibited when the layer of the cured product of the optical filter composition has a specific thickness included in the range of 100 to 300 μm. That is, the layer of the cured product of the optical filter composition does not have to satisfy such characteristics in the entire range of 100 to 300 μm.

Desirably, the composition for an optical filter cures the coating film of this composition to form a layer having a thickness of 100 to 300 μm, and makes light having a wavelength of 300 nm to 1200 nm incident on this layer at an incident angle of 0 °. It 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 cutoff wavelength having a spectral transmittance of 50% at a wavelength of 600 nm to 750 nm and a spectral transmittance of 50% at a wavelength of 600 nm to 750 nm is within the range of 610 nm to 680 nm. Exists.
(IV) The first UV cutoff wavelength having a spectral transmittance of 50% at a wavelength of 350 nm to 450 nm and having a spectral transmittance of increasing at a wavelength of 350 nm to 450 nm, and having a spectral transmittance of 50% at a wavelength of 380 nm to 430 nm. Exists.

  The composition for optical filters has a viscosity of 1 to 200 mPa · s at 22 to 23 ° C., for example. In this case, the composition for optical filters tends to flow easily, which is disadvantageous for forming a coating film by the composition for optical filters. In addition, it is necessary to add a relatively large amount of solvent (dispersion medium) in order to adjust the viscosity of the optical filter composition to such a range, and the treatment for curing the coating film of the optical filter composition can be performed. It can be long. Therefore, until now, it is desirable for the present inventors to adjust the viscosity of the optical filter composition at 22 to 23 ° C. to exceed the viscosity of 200 mPa · s (for example, 300 mPa · s or more). I was thinking. On the other hand, the present inventors 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 was newly found that adjusting the viscosity of the composition for an optical filter at 22 to 23 ° C. to 1 to 200 mPa · s is desirable from the viewpoint of reducing the haze of the UV-IR absorption layer. Even when the above-mentioned UV-IR absorber in the optical filter composition is aggregated to such an extent that does not affect the transmittance characteristics of the UV-IR absorption layer, the aggregated state in the coating film of the optical filter composition is It is considered that the haze of the UV-IR absorption layer tends to be high unless it is appropriately resolved. On the other hand, when the composition for optical filters has a viscosity of 1 to 200 mPa · s at 22 to 23 ° C., the composition for optical filters appropriately flows in the coating film of the composition for optical filters, and the UV-IR absorber is used. It is considered that the aggregation state of is easily eliminated. As a result, it is considered that the haze of the UV-IR absorption layer can be reduced. When the viscosity of the optical filter composition at 22 to 23 ° C. is less than 1 mPa · s, the amount of the solvent in the optical filter composition is too large, and the physical distance between the components forming the UV-IR absorption layer is increased. growing. Therefore, there is a possibility that the UV-IR absorption layer cannot be properly formed.

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

  The composition for an optical filter desirably has a viscosity of 2 to 180 mPa · s at 22 to 23 ° C., and more desirably 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 surely reduced to 5% or less.

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

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

  In the composition for optical filters, the content of copper ions is, for example, 0.5 to 2.2 mass%. In this case, the content of copper ions in the composition is relatively small, aggregation of the UV-IR absorber is less likely to occur in the coating film of the optical filter composition, and it is considered that the haze of the UV-IR absorption layer is easily reduced. To 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. Further, the optical filter composition further contains, for example, a predetermined solvent (dispersion medium). The composition for optical filters may contain, for example, an alkoxysilane monomer. When the composition for an optical filter contains an alkoxysilane monomer, it is possible to prevent the particles of the UV-IR absorber from aggregating in the composition for an optical filter, and even if 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 of 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 solution of the copper salt and stirred to prepare a solution A. To do. Further, the first phosphonic acid or the first sulfonic acid is added to a predetermined solvent such as THF and stirred to prepare the liquid B. When a plurality of types of phosphonic acid or sulfonic acid is used as the primary phosphonic acid or primary sulfonic acid, the primary phosphonic acid or primary sulfonic acid is added to a predetermined solvent such as THF and stirred, and then the primary phosphonic acid is added. Liquid B may be prepared by mixing a plurality of preparatory liquids prepared for each type of acid or primary sulfonic acid. An alkoxysilane monomer may be added in the preparation of the liquid B.

  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, the solution C is subjected to desolvation treatment for a predetermined time while being heated to obtain the solution D. This removes components generated by dissociation of a solvent such as THF and a copper salt such as acetic acid (boiling point: about 118 ° C.), and the primary phosphonic acid or primary sulfonic acid and copper ions form a UV-IR absorber. Is generated. The temperature for heating the liquid C is determined based on the boiling points of the components to be removed which are dissociated from the copper salt. In the solvent removal treatment, the solvent such as toluene (boiling point: about 110 ° C.) used to obtain the liquid C also volatilizes, but the solvent remains in the liquid D so that the viscosity of the liquid D falls within a desired range. To do. The addition amount of the solvent for obtaining the liquid C may be adjusted so that the viscosity of the liquid D falls within a desired range, or the time for the desolvation treatment may be adjusted.

  When the composition for an optical filter further contains a secondary phosphonic acid or a secondary sulfonic acid, the H liquid is further prepared, for example, 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, 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 solution of the copper salt and stirred to prepare a solution E. To do. Further, the second phosphonic acid or the second sulfonic acid is added to a predetermined solvent such as THF and the mixture is stirred to prepare a liquid 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 give the second phosphonic acid. Alternatively, the F liquid may be prepared by mixing a plurality of preliminary liquids prepared for each type of the secondary sulfonic acid. While stirring Solution E, Solution F is added to 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 liquid G. Next, the solution G is subjected to desolvation treatment for a predetermined time while heating the solution G to obtain the solution H. As a result, a component generated by dissociation of a solvent such as THF and a copper salt such as acetic acid is removed, and another UV-IR absorber is generated by the secondary phosphonic acid or secondary sulfonic acid and the copper ion. The temperature for heating the G liquid is determined in the same manner as the C liquid, and the solvent for obtaining the G liquid is also determined in the same manner as the C liquid. The addition amount of the solvent for obtaining the liquid 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. Further, when the composition for an optical filter contains a UV-IR absorber formed by a secondary phosphonic acid or a secondary sulfonic acid and copper ions, a matrix resin such as a silicone resin is added to the liquid D and stirred. The composition for optical filter can be prepared by further adding the solution H to the solution I thus obtained and stirring.

Next, the composition for an optical filter is applied to one main surface of a predetermined substrate to form a coating film. The substrate is not particularly limited, but a glass substrate, a resin substrate, or a metal substrate (steel substrate or stainless substrate) can be used. For example, a liquid optical filter composition is applied to one main surface of the substrate by spin coating, die coating, or application with a dispenser to form a coating film. Next, this coating film is subjected to a predetermined heat treatment to cure the coating film. For example, the coating film is exposed to an environment having a temperature of 40 ° C to 200 ° C. If necessary, the coating film is subjected to a humidification treatment so that the alkoxysilane monomer contained in the optical filter composition is sufficiently hydrolyzed and polycondensed. For example, the cured coating film is exposed to an environment of a temperature of 40 ° C. to 100 ° C. 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 perform these reactions. However, if water is added to the composition for an optical filter in advance when manufacturing the optical filter, the phosphoric acid ester or the UV-IR absorber deteriorates in the process of forming the UV-IR absorbing layer, and the UV -IR absorption performance may be deteriorated or durability of the optical filter may be impaired. For this reason, it is desirable to perform the humidification treatment after the coating film is cured by a predetermined heat treatment. In this way, the UV-IR absorption layer 10 can be formed on the substrate. After that, 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, a viscosity of 1 to 200 mPa · s at 22 to 23 ° C. In this case, the composition for an optical filter contains a relatively large amount of solvent. Therefore, when the coating film of the optical filter composition is cured by heating, if the coating film is heated from the beginning at a high temperature, the UV-IR absorption layer is likely to be cracked due to rapid volatilization of the solvent. Therefore, after heating the coating film of the composition for an optical filter in a relatively low temperature environment of 60 ° C. or lower for a predetermined time, the coating film may be heated in a relatively high temperature environment having a temperature higher than 60 ° C. for a predetermined time. desirable. It is possible to prevent the solvent from being volatilized slowly, and at the same time, the bonding due to the polycondensation reaction of the alkoxysilane monomer or the silicone resin to proceed in parallel to cause cracks in the UV-IR absorption layer. 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 exposed to an environment exceeding 60 ° C. after being heated for 20 minutes or more in an environment of 45 ° C. or less.

<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 constituents of the optical filters 1b to 1f that are the same as or correspond to the constituents of the optical filter 1a are designated 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 technically contradictory.

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 arranged on both surfaces thereof. The antireflection film 30 is a film that is formed so as to form an interface between the optical filter 1b and air and that reduces reflection of light in the visible light region. The antireflection film 30 is, for example, a film formed of a dielectric material such as resin, oxide, and fluoride. The antireflection film 30 may be a multilayer film formed by laminating two or more kinds 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. 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 arranged on both main surfaces of the UV-IR absorption layer 10, or may be arranged on only one main surface. The optical filter 1b can contribute to lowering 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 is disposed on one main surface of the UV-IR absorption layer 10 and reflects infrared rays and / or ultraviolet rays. I have it. The reflective film 40 is, for example, a film formed by depositing 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 laminated. is there. As the high refractive index material, a material having a refractive index of 1.7 to 2.5 such as TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , ZnO, and In ₂ O ₃ is used. As the low refractive index material, a material having a refractive index of 1.2 to 1.6 such as SiO ₂ , Al ₂ O ₃ and MgF ₂ is used. The method of 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 reflection film may be formed so as to form both main surfaces of the optical filter (not shown). When the reflective film is 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 the optical filter is less likely to warp.

  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 (for example, 80% or more) at 450 nm to 600 nm. Depending on the case, the transparent dielectric substrate 20 may have absorption ability in the ultraviolet region or the infrared region.

  The transparent dielectric substrate 20 is made of glass or resin, for example. When the transparent dielectric substrate 20 is made of glass, the glass contains, for example, borosilicate glass such as D263 Teco, soda lime glass (blue plate), white plate glass such as B270, non-alkali glass, or copper. Infrared absorptive glass such as phosphate glass or fluorophosphate glass containing copper. When the transparent dielectric substrate 20 is infrared absorbing glass such as copper-containing phosphate glass or copper-containing fluorophosphate glass, the transparent dielectric substrate 20 has infrared absorbing performance and UV. 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 lowered. Such infrared absorbing glass is, for example, BG-60, BG-61, BG-62, BG-63, or BG-67 manufactured by Schott, 500EXL manufactured by Nippon Electric Glass Co., Ltd., or HOYA. CM5000, CM500, C5000, or C500S manufactured by the same 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, since sapphire has a high hardness, it is hard to be scratched. Therefore, the plate-shaped sapphire may be disposed as a scratch-resistant protective material (protect filter) on the front surface of a camera module or a lens provided in a mobile terminal such as a smartphone or a mobile phone. By forming the UV-IR absorption layer 10 on such a plate-shaped sapphire, it is possible to shield the camera module and the lens as well as to block the ultraviolet ray or the infrared ray. As a result, it is not necessary to dispose an optical filter having an ultraviolet or infrared shielding property around a solid-state image sensor such as CCD or CMOS or inside a camera module. Therefore, if the UV-IR absorption layer 10 is formed on the plate-shaped sapphire, it can contribute to the lowering of the height of the camera module.

  When the transparent dielectric substrate 20 is made of resin, the resin is, for example, (poly) olefin resin, polyimide resin, polyvinyl butyral resin, polycarbonate resin, polyamide resin, polysulfone resin, polyether sulfone resin, 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 added to the transparent dielectric substrate 20 and the UV in order 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. This allows the optical filter 1e to exhibit the optical performances (i) to (iv) above by the two UV-IR absorption layers 10 instead of the one UV-IR absorption layer 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 on the both main surfaces of the transparent dielectric substrate 20 is so that the thickness of the UV-IR absorption layer 10 required for the optical filter 1e to obtain desired optical characteristics is evenly or unevenly distributed. The -IR absorption layer 10 is formed. As a result, 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 shortened, and the time for curing the coating film of the optical filter composition can be shortened. When the transparent dielectric substrate 20 is thin, if the UV-IR absorbing layer 10 is formed only on one main surface of the transparent dielectric substrate 20, it occurs when the UV-IR absorbing layer 10 is formed from the optical filter composition. The optical filter may warp due to the stress associated with the contraction. 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. You may form in.

  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 arranged on both main surfaces of the optical filter 1f, but may be arranged only on 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 so as to include an infrared absorption film (not shown) separately from the UV-IR absorption layer 10, if necessary. The infrared absorbing film contains, for example, an organic infrared absorbing agent such as cyanine-based, phthalocyanine-based, squarylium-based, diimmonium-based, and azo-based, or an infrared absorbent composed 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 absorber has a small wavelength range (absorption band) of light that can be absorbed, and is suitable for absorbing light having a wavelength in a specific range.

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

  The above infrared absorber or ultraviolet absorber may be contained in the transparent dielectric substrate 20 made of resin in advance. The infrared absorbing film or the ultraviolet absorbing film can be formed by, for example, forming a film containing an infrared absorbing agent or a resin containing the ultraviolet absorbing agent. In this case, the resin is required to be able to appropriately dissolve or disperse the infrared absorber or the ultraviolet absorber and to be transparent. Examples of such resin include (poly) olefin resin, polyimide resin, polyvinyl butyral resin, polycarbonate resin, polyamide resin, polysulfone resin, polyether sulfone resin, polyamideimide resin, (modified) acrylic resin, epoxy resin, and silicone resin. Can be illustrated.

  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 inside the imaging device (on the side closer to the subject) in order to bring the spectral sensitivity of the imaging device closer to human visual sensitivity.

  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 image sensor 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 recess that contacts an opening formed in the center of the optical filter support housing 7. The optical filter support housing 7 is fixed to the optical system housing 8. Inside the optical system casing 8, the lens system 2, the low-pass filter 3, and the solid-state image sensor 4 are arranged in this order along the optical axis. The solid-state image sensor 4 is, for example, a CCD or a CMOS. The light from the subject is filtered by the optical filter 1d to block ultraviolet rays and infrared rays, is then condensed by the lens system 2, passes through the low-pass filter 3, and enters the solid-state image sensor 4. The electric signal generated by the solid-state image sensor 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 (protection filter) that protects the lens system 2. In this case, preferably, a sapphire substrate is 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 arranged on the outer side (the side opposite to the solid-state image sensor 4 side). Thereby, 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 preferably has the optical performances (i) to (iv) described above, and more preferably has the optical performances (v) to (vii). As a result, there is no need to dispose an optical filter for cutting infrared rays or ultraviolet rays near the solid-state image sensor 4, and the camera module 100 can be easily lowered. It should be noted that the camera module 100 shown in FIG. 2 is a schematic diagram for exemplifying the arrangement of each component and the like, and illustrates a mode in which the optical filter 1d is used as a protect 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 if necessary, Other filters may be provided.

  The present invention will be described in more detail by way of examples. The present invention is not limited to the examples below.

<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 PRYSURF A208N (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), which is a phosphoric acid ester compound, was added to the obtained copper acetate solution and stirred for 30 minutes to obtain a solution A. 40 g of THF was added to 0.706 g of phenylphosphonic acid and stirred for 30 minutes to obtain solution B-1. 40 g of THF was added to 4.230 g of 4-bromophenylphosphonic acid, and the mixture was stirred for 30 minutes to obtain solution B-2. 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 mixed liquid, and the mixture was further stirred for 1 minute to obtain a liquid 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, and the mixture was stirred 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 Rikakikai Co., Ltd., model: OSB-2100), while being desolvated by a rotary evaporator (manufactured by Tokyo Rikakikai Co., Ltd., model: N-1110SF). went. The set temperature of the oil bath was adjusted to 105 ° C. Then, the D liquid according to Example 1 after the desolvation treatment was taken out from the flask. The solvent removal treatment was carried out so that the viscosity of the liquid D was lowered to some extent without completely removing the solvent in the solvent removal treatment. Liquid D, which is a dispersion liquid of fine particles of phenyl copper phosphonate (UV-IR absorber), was transparent, and the fine particles were well dispersed in liquid D. The obtained liquid D was 107.06 g. Table 1 shows the addition amount of toluene for obtaining the D liquid, the mass of the obtained D liquid, and the concentration of copper ions in the D liquid.

  4.500 g of copper acetate monohydrate and 240 g of THF were mixed and stirred for 3 hours to obtain a copper acetate solution. Next, to the obtained copper acetate solution, 2.572 g of Phlysurf A208N, which is a phosphoric acid ester compound, was added and stirred for 30 minutes to obtain solution E. Further, 40 g of THF was added to 2.886 g of n-butylphosphonic acid and stirred for 30 minutes to obtain a liquid F. The liquid F was added to the liquid E while stirring the liquid E, and the mixture was stirred at room temperature for 1 minute. Next, 84 g of toluene was added to this solution, and the mixture was stirred at room temperature for 1 minute to obtain a liquid G. This solution G was placed in a flask and heated with an oil bath to perform desolvation treatment with a rotary evaporator. The set temperature of the oil bath was adjusted to 105 ° C. Then, the H liquid according to Example 1 after the desolvation treatment was taken out from the flask. The solvent was not completely removed in the desolvation treatment, and the desolvation treatment was carried out so that the viscosity of the H solution became a predetermined viscosity. Liquid H, which is a dispersion liquid of fine particles of copper butylphosphonate (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 liquid, the mass of the obtained H liquid, and the concentration of copper ions in the H liquid.

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

  A surface antifouling coating agent (manufactured by Daikin Industries, Ltd., product name: OPTOOL DSX, concentration of active ingredient: 20% by mass) and 0.1 g of Novec 7100 (manufactured by 3M, ingredient: hydrofluoroether) were mixed. The mixture was stirred for 5 minutes to prepare a fluorination agent (concentration of active ingredient: 0.1% by mass). This fluorination agent was applied to a transparent glass substrate (manufactured by SCHOTT, product name: D263 Teco) made of borosilicate glass having dimensions of 76 mm × 76 mm × 0.21 mm at a rotation speed of 3000 rpm (revolutions per minute). Spin coated. Then, the transparent glass substrate was left at room temperature for 24 hours to dry the coating film of the fluorine-treating agent, and a glass substrate which had been subjected to fluorine treatment (easy peeling treatment) was obtained.

  The optical filter composition according to Example 1 was applied to a square area of about 30 mm × 30 mm at the center of the main surface of a glass substrate that had been treated with fluorine using a dispenser to form a coating film. A frame having a square hole of 30 mm × 30 mm in the center and having a thickness of 5 mm was attached to a glass substrate, and the optical filter composition according to Example 1 was applied to the inside of the frame. Next, the transparent glass substrate having the undried coating film was placed in an oven and heat-treated at 45 ° C. for 2 hours and at 85 ° C. for 6 hours to cure the coating film. Then, the glass substrate having the coating film was placed in a constant temperature and humidity chamber set at a temperature of 85 ° C. and a relative humidity of 85% for 2 hours to perform a humidification treatment. After that, the layer formed by curing the coating film of the composition for an optical filter was peeled from the glass substrate, and the optical filter according to Example 1 was produced.

<Examples 2 to 15 and Comparative Example 1>
Except that the preparation conditions of the D liquid were changed so that the addition amount of toluene for obtaining the D liquid, the mass of the obtained D liquid, and the concentration of copper ions in the D liquid were as shown in Table 1. In the same manner as in Example 1, a D liquid according to Examples 2 to 15 and a D liquid according to Comparative Example 1 were prepared. Except that the preparation conditions of the H liquid were changed so that the addition amount of toluene for obtaining the H liquid, the mass of the obtained H liquid, and the concentration of copper ions in the H liquid were as shown in Table 2. In the same manner as in Example 1, solutions H of Examples 2 to 15 and Comparative Example 1 were prepared. The optical filter compositions according to Examples 2 to 15 and Comparative Example 1 were prepared in the same manner as in Example 1 except that the amounts of D liquid, H liquid, and silicone resin were adjusted as shown in Table 3. did. Further, each of the examples was performed in the same manner as in Example 1 except that the optical filter compositions according to Examples 1 to 15 and Comparative Example 1 were used instead of the optical filter composition according to Example 1. 2-15 and the optical filter which concerns on the 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 PRYSURF A208N (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), which is a phosphoric acid ester compound, was added to the obtained copper acetate solution and stirred for 30 minutes to obtain a solution A. 40 g of THF was added to 0.769 g of p-toluenesulfonic acid, and the mixture was stirred for 30 minutes to obtain solution B-1. 40 g of THF was added to 4.230 g of 4-bromobenzenesulfonic acid and stirred for 30 minutes to obtain solution B-2. 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 mixed liquid, and the mixture was further stirred for 1 minute to obtain a liquid 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, and the mixture was stirred 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 Rikakikai Co., Ltd., model: OSB-2100), while being desolvated by a rotary evaporator (manufactured by Tokyo Rikakikai Co., Ltd., model: N-1110SF). went. The set temperature of the oil bath was adjusted to 105 ° C. Then, the D liquid according to Example 1 after the desolvation treatment was taken out from the flask. The solvent removal treatment was carried out so that the viscosity of the liquid D was lowered to some extent without completely removing the solvent in the solvent removal treatment. Liquid D, which is a dispersion liquid of fine particles of phenyl copper sulfonate (UV-IR absorber), was transparent, and the fine particles were well dispersed in liquid D. The obtained liquid D was 107.12 g. Table 1 shows the addition amount of toluene for obtaining the D liquid, the mass of the obtained D liquid, and the concentration of copper ions in the D liquid.

  4.500 g of copper acetate monohydrate and 240 g of THF were mixed and stirred for 3 hours to obtain a copper acetate solution. Next, to the obtained copper acetate solution, 2.572 g of Phlysurf A208N, which is a phosphoric acid ester compound, was added and stirred for 30 minutes to obtain solution E. Further, THF 40 g was added to 1-butanesulfonic acid 2.886 g and stirred for 30 minutes to obtain a liquid F. The liquid F was added to the liquid E while stirring the liquid E, and the mixture was stirred at room temperature for 1 minute. Next, 84 g of toluene was added to this solution, and the mixture was stirred at room temperature for 1 minute to obtain a liquid G. This solution G was placed in a flask and heated with an oil bath to perform desolvation treatment with a rotary evaporator. The set temperature of the oil bath was adjusted to 105 ° C. Then, the H liquid according to Example 1 after the desolvation treatment was taken out from the flask. The solvent was not completely removed in the desolvation treatment, and the desolvation treatment was carried out so that the viscosity of the H solution became a predetermined viscosity. Liquid H, which is a dispersion liquid of fine particles of copper butanesulfonate (UV-IR absorber), was transparent, and 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 liquid, the mass of the obtained H liquid, and the concentration of copper ions in the H liquid.

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

(Viscosity measurement of the composition for optical filters)
Using a vibration type viscometer (manufactured by Sequonic, probe: PR-10L, controller: VM-10A), the viscosities of the optical filter compositions according to each Example and Comparative Example 1 at 22 to 23 ° C. were measured. . The results are shown in Table 3. As shown in Table 3, the viscosity of the optical filter composition according to each example at 22 to 23 ° C. was included in the range of 1 to 200 mPa · s, while the optical filter composition according to Comparative Example 1 was used. The viscosity at 22 to 23 ° C. was 330 mPa · s.

(Measurement of solid content of optical filter composition and calculation of solid content ratio)
An aluminum sheet (manufactured by Sumikari Aluminum Foil Co., Ltd., thickness: 12 μm) is laid on the bottom of a stainless steel tray, and each example and comparative example 1 are set so that the cured sheet has a thickness of 100 to 300 μm. The composition for an optical filter according to 1. was applied to prepare a pre-curing sample. The pre-curing sample was placed in an oven whose internal temperature was kept at 45 ° C, and the internal temperature of the oven was kept at 45 ° C for 2 hours as it was. Then, 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 as it was. After that, the power of the oven was turned off to allow natural cooling, and after the temperature inside the oven had dropped to a temperature of about room temperature, the sample was taken out from the oven. Next, the sample is placed in a constant temperature and humidity chamber, and the inside of the constant temperature and humidity chamber is changed to an environment of temperature 85 ° C and relative humidity of 85% over 45 minutes, and the constant temperature and humidity chamber is kept in that environment for 2 hours. I kept it. After that, the environment of the constant temperature and constant humidity tank was sufficiently lowered over 45 minutes to reduce the temperature and humidity, and then the sample was taken out from the constant temperature and constant humidity tank. The sample was well dried 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 optical filter composition according to each Example and Comparative Example 1 was determined. The results are shown in Table 3.

(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 according to each example and comparative example 1 was measured. The thickness of the filter was calculated. The results are shown in Table 4.

(Measurement of haze)
A haze meter (Murakami Color Research Laboratory, product name: HM-65L2) was used to measure the haze of the optical filters according to each Example and Comparative Example 1 in accordance with JIS K 7136: 2000.
The results are shown in Table 4.

(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 made incident on the optical filters according to each of Examples and Comparative Example 1 at an incident angle of 0 °. The transmittance 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 are obtained for the optical filters according to each of the examples and the comparative example 1. It was The results are shown in Table 4. The transmittance spectra of Examples 1, 4, 13, 14, and 15 and Comparative Example 1 are shown in FIGS. 3 to 8, 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%. Further, in the optical filters according to each example, 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 respective examples had good transmittance characteristics. In addition, the haze of the optical filter according to each example was 5% or less. Therefore, the optical filters according to the respective 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 wavelengths of 450 nm to 600 nm was 81.9%, and the average transmittance at wavelengths of 300 nm to 350 nm was less than 0.2%. In addition, in the optical filter according to each example, the IR cutoff wavelength was 631 nm and the UV cutoff wavelength was 407 nm. From this result, the optical filter according to Comparative Example 1 had a good transmittance characteristic to some extent. On the other hand, the haze of the optical filter according to Comparative Example 1 was 8.4%, which greatly exceeded 5%. Therefore, it was hard to say that the optical filter according to Comparative Example 1 has desirable optical characteristics from the viewpoint of haze.

Claims (7)

Containing at least one acid of a phosphonic acid having an aryl group and a sulfonic acid having an aryl group, a phosphoric acid ester, an alkoxysilane or a hydrolyzate of an alkoxysilane, and a copper ion ,
Has a viscosity of 1 to 200 mPa · s at 22 to 23 ° C.,
Containing 3 to 17 mass% solids ,
The content of the copper ions is 0.5 to 2.2 mass%,
Composition for optical filter.   When the coating film of the composition for an optical filter is cured to form a layer having a thickness of 100 to 300 μm, the layer can absorb ultraviolet rays and infrared rays, and the haze of the layer is 5% or less. The composition of claim 1, wherein the composition is: When the acid includes the phosphonic acid, 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,
When the acid includes the sulfonic acid, the sulfonic acid includes a phenyl group or a sulfonic acid having a halogenated phenyl group in which at least one hydrogen atom in the phenyl group is substituted with a halogen atom,
The composition according to claim 1 or 2. When the acid comprises the phosphonic acid, the phosphonic acid further comprises a phosphonic acid having an alkyl group,
When the acid includes the sulfonic acid, the sulfonic acid further includes a sulfonic acid having an alkyl group,
The composition according to claim 3. Further contains resin,
The composition according to any one of claims 1 to 4, wherein the acid content is 5 to 400 parts by mass with respect to 100 parts by mass of the resin. Comprising curing a composition according to any one of claim 1 5, a method of manufacturing an optical filter.   The method according to claim 6, wherein the coating film of the composition is heated in an environment of 60 ° C or lower for 10 minutes or more, and then the composition is cured by exposing the coating film to an environment of higher than 60 ° C.

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