TW201938698A - Infrared absorbing composition capable of suppressing generation of aggregated foreign matter and exerting good infrared absorbing ability - Google Patents

Abstract

The present invention provides an infrared absorbing composition, which suppresses generation of aggregated foreign matter, in addition, which is capable of serving as an infrared shielding filter of a solid-state imaging device to exert good infrared absorbing ability by using the resulting infrared absorbing film in combination with a dielectric multilayer film. The infrared absorbing composition of the present invention comprises: two or more organic dyes having a maximum absorbing wavelength in the range of more than 650 nm and less than 900 nm; an inorganic compound having a maximum absorbing wavelength in the range of more than 900 nm and less than 2000 nm; a binder resin; and a solvent, wherein the infrared absorbing composition satisfies the following formula (I): X > Y ≥ 0.80Z. In formula (I), X, Y and Z are in the order of: the average absorbance values of the infrared absorbing composition with the wavelength in the range of more than 700 nm and less than 800 nm, the wavelength in the range of more than 800 nm and less than 900 nm, and the wavelength in the range of more than 900 nm and less than 1200 nm.

Description

Infrared absorbing composition

The present invention relates to an infrared absorbing composition.

Charge-Coupled Device (CCD) image sensors or Complementary metal oxide semiconductor (CMOS) image sensors are mounted in video cameras, digital cameras, mobile phones with camera functions, etc. Solid-state imaging element. The sensitivity of the photodiodes included in these solid-state imaging elements is in a range from a visible light region to an infrared region. Therefore, a filter for shielding infrared rays is provided in the solid-state imaging device. With the infrared shielding filter, the sensitivity of the solid-state imaging device can be corrected in a manner close to the visual sensitivity of humans.

As the infrared shielding filter, an infrared absorbing film formed of an infrared absorbing composition and a dielectric multilayer film as a laminate of a plurality of dielectric layers are known. As the infrared absorbing composition, a composition containing a metal oxide such as cesium tungsten oxide and an organic pigment has been developed (see Patent Documents 1 and 2). The infrared absorbing film is formed by, for example, applying an infrared absorbing composition containing the metal oxide, an organic pigment, a solvent, and the like, and then drying it by heating.
[Prior Art Literature]
[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2013-195480
[Patent Document 2] Japanese Patent Laid-Open No. 2014-197170

[Problems to be Solved by the Invention]
The cesium tungsten oxide is particularly a material having excellent infrared shielding ability in a wavelength range of 900 nm or more. In the aforementioned Patent Documents 1 and 2, an infrared absorbing composition using cesium tungsten oxide with more formulations than organic pigments is also implemented to improve infrared shielding performance in the wavelength range.

However, the present inventors have found that in such an infrared absorbing composition, when the content of an inorganic oxide such as cesium tungsten oxide is high, agglomerated foreign matter increases. Foreign matter in the infrared absorbing composition affects infrared shielding properties, contrast characteristics, transparency, and the like of the obtained infrared absorbing film. The contrast characteristic is a characteristic related to the ratio of the minimum value to the maximum value (extinction ratio) of the amount of transmitted light when the light is made incident under a predetermined condition. The larger the ratio, the more excellent the contrast characteristics, which are reduced due to the presence of foreign matter or the like. In addition, there is a case where a patterned infrared absorbing film is formed using the infrared absorbing composition, but the presence of a foreign substance also affects the patternability. Furthermore, when the content of an inorganic oxide such as cesium tungsten oxide in the infrared absorbing composition is high, it also affects the visible light transmittance, and the device performance may be impaired.

On the other hand, as the infrared shielding filter, a design in which an infrared absorbing film formed of an infrared absorbing composition and a dielectric multilayer film are combined is also considered. However, the incident angle dependence of the dielectric multilayer film is large. Therefore, in the infrared shielding filter of the solid-state imaging element, it is not good to design a dielectric multilayer film to shield infrared rays near the visible light region.

The present invention has been made based on the above-mentioned circumstances, and an object thereof is to provide an infrared absorbing composition in which generation of agglomerated foreign matter is suppressed, and by using the obtained infrared absorbing film in combination with a dielectric multilayer film, As an infrared shielding filter of a solid-state imaging element, it exhibits good infrared absorption ability.

[Means for solving problems]
An invention made to solve the above-mentioned problem is an infrared absorbing composition containing two or more organic pigments having a maximum absorption wavelength in a range of 650 nm to 900 nm, and a wavelength of 900 nm to 2000. An inorganic compound having a maximum absorption wavelength in a range of nm or less; a binder resin; and a solvent, and satisfying the following formula (I).
X ＞ Y ≧ 0.80Z ・ ・ ・ (I)
(In the formula (I), X is an average value of absorbance of the infrared absorbing composition in a range of wavelengths from 700 nm to 800 nm; Y is a value in a range of wavelengths from 800 nm to 900 nm. The average value of the absorbance of the infrared absorbing composition; Z is the average value of the absorbance of the infrared absorbing composition in a range of wavelengths from 900 nm to 1200 nm.)

[Effect of the invention]
According to the present invention, it is possible to provide an infrared absorbing composition in which generation of condensed foreign matter is suppressed, and by using the obtained infrared absorbing film in combination with a dielectric multilayer film, it can be used as an infrared shielding filter for a solid-state imaging element Film and exert good infrared absorption ability.

Hereinafter, an infrared absorbing composition according to an embodiment of the present invention will be described in detail.

＜ Infrared absorbing composition ＞
The infrared absorbing composition (hereinafter, also simply referred to as a "composition") according to an embodiment of the present invention contains:
[A] Two or more organic pigments having a maximum absorption wavelength in a range of wavelengths from 650 nm to 900 nm;
[B] An inorganic compound having a maximum absorption wavelength in a range of wavelengths from 900 nm to 2000 nm;
[C] adhesive resin; and
[D] Solvent,
In addition, the following formula (I) is satisfied.
X ＞ Y ≧ 0.80Z ・ ・ ・ (I)
(In the formula (I), X is an average value of absorbance of the infrared absorbing composition in a range of wavelengths from 700 nm to 800 nm; Y is a value in a range of wavelengths from 800 nm to 900 nm. The average value of the absorbance of the infrared absorbing composition; Z is the average value of the absorbance of the infrared absorbing composition in a range of wavelengths from 900 nm to 1200 nm.)

In the optical characteristics of the infrared absorbing composition, the formula (I) shows a tendency that the absorption ability of infrared rays having a longer wavelength is low and the absorption ability of infrared rays having a shorter wavelength is high. This composition contains an [A] organic pigment and has optical characteristics satisfying the formula (I). Therefore, the [A] organic pigment can sufficiently shield infrared rays in a region near visible light having a wavelength of 700 nm to 800 nm. In addition, since this composition contains an [B] inorganic compound, it can absorb infrared rays having a wavelength of 900 nm or more. Furthermore, as represented by the formula (I), in this composition, the shielding property of infrared rays having a longer wavelength is not high. That is, the content of [B] inorganic compound is relatively small. Therefore, in this composition, generation | occurrence | production of the aggregation foreign material by [B] inorganic compound can be suppressed. On the other hand, although the infrared shielding property of the composition having a relatively long wavelength is not high in this way, it can also sufficiently shield the wavelength by using it in combination with a dielectric multilayer film having a high absorption capacity of infrared rays having a wavelength of 900 nm or more. Long infrared. In addition, as described above, the composition has high infrared shielding ability in a region close to visible light, and thus can reduce the incidence angle dependency caused by the dielectric multilayer film when used in combination with the dielectric multilayer film. That is, the composition is preferably used in combination with a dielectric multilayer film having a low infrared shielding property on the shorter wavelength side and a high infrared shielding property on the longer wavelength side, thereby reducing the incidence angle dependency. At the same time, it has a good infrared shielding ability in a wide wavelength range.

Regarding the relationship between X and Y, X / 2> Y is preferable, and X / 3> Y is more preferable. In the case where such a relationship is satisfied, the content of the [B] inorganic compound is smaller, and the generation of agglomerated foreign matter is suppressed. On the other hand, X / 100 <Y is preferable, and X / 10 <Y is more preferable. In the case where such a relationship is satisfied, by using it in combination with a dielectric multilayer film, a good infrared absorption ability can be exhibited in a wide wavelength range. In addition, the X, Y, and Z can be adjusted by the blending ratio of each component, especially the [A] organic pigment and the [B] inorganic compound.

Regarding the relationship between X and Z, X / 2> Z is preferable, and X / 3> Z is more preferable. On the other hand, X / 100 <Z is preferable, and X / 10 <Z is more preferable. In the case where such a relationship is satisfied, by using it in combination with a dielectric multilayer film, a good infrared absorption ability can be exhibited in a wide wavelength range.

This composition contains not only the above-mentioned [A] component to [D] component, but also other components. Hereinafter, each component is demonstrated in detail.

([A] organic pigment)
[A] An organic pigment contains two or more components having a maximum absorption wavelength in a wavelength range of 300 nm to 1200 nm and a wavelength range of 650 nm to 900 nm. Each of the two or more organic pigments constituting the component [A] has a maximum absorption wavelength in a range of a wavelength of 650 nm or more and 900 nm or less. Here, in this specification, the "maximum absorption wavelength" refers to the relationship between the wavelength and the absorbance when a two-dimensional graph of the X axis and the Y axis (where the X axis is the wavelength and the Y axis is the absorbance) , The absorbance changes from increasing to decreasing apex. The "maximum absorption wavelength" refers to a wavelength having the largest absorbance among the maximum absorption wavelengths. By containing an organic pigment [A], this composition can fully shield infrared rays, especially in a region near visible light, while having sufficient visible light transmittance. The lower limit of the maximum absorption wavelength is preferably 680 nm. On the other hand, the upper limit of the maximum absorption wavelength is preferably 850 nm. The [A] organic pigment is usually dissolved in the [D] solvent.

[A] Two or more organic pigments may be used in combination, or three or more may be used in combination. By using a plurality of organic pigments in combination, particularly the infrared shielding properties close to the wavelength of visible light can be improved. When used in combination with a dielectric multilayer film, the incident angle dependency may be reduced. The upper limit of the number of types of the [A] organic pigment is not particularly limited, and may be, for example, 10 types, 5 types, 3 types, or 2 types.

[A] The organic pigment preferably contains a first organic pigment and a second organic pigment, and satisfies the following formula (II).
10 ≦ λ2-λ1 ≦ 120 ... (II)
(In formula (II), λ1 is the maximum absorption wavelength (nm) of the first organic pigment; λ2 is the maximum absorption wavelength (nm) of the second organic pigment)

When the difference between the maximum absorption wavelengths of the two organic pigments is within the above range, better infrared absorption or visible light transmission can be exhibited. The lower limit of the maximum absorption wavelength difference (λ2-λ1) is more preferably 20 nm, and even more preferably 40 nm. The upper limit of the maximum absorption wavelength difference (λ2-λ1) is more preferably 60 nm. Furthermore, in the case where [A] the organic pigment contains three or more organic pigments, it is preferable that the organic pigment having the smallest maximum absorption wavelength and the organic pigment having the largest maximum absorption wavelength satisfy the relationship of the formula (II). .

In the case where [A] an organic pigment includes three organic pigments (organic pigment (A), organic pigment (B), and organic pigment (C) in order of maximum absorption wavelength in ascending order), as the maximum absorption of the organic pigment (A) The wavelength is preferably 650 nm or more and less than 720 nm. The maximum absorption wavelength of the organic pigment (B) is preferably 720 nm or more and less than 750 nm. The maximum absorption wavelength of the organic pigment (C) is preferably 750 nm or more and less than 850 nm. The maximum absorption wavelength difference between the organic pigment (A) and the organic pigment (B) and the maximum absorption wavelength difference between the organic pigment (B) and the organic pigment (C) are preferably 10 nm or more, and more preferably 20 nm or more. . By using these three organic pigments in combination, especially the infrared shielding properties close to the wavelength of visible light can be improved, and when used in combination with a dielectric multilayer film, the incident angle dependency may be reduced.

[A] The organic dye includes an organic dye or an organic pigment, and an organic dye is preferred. By using an organic dye, the solubility of the [D] solvent is improved, and the generation of agglomerated foreign matter can be further suppressed.

As the organic dye, a diiminium compound, a stilbene compound, a cyanine compound, a phthalocyanine compound, a naphthalocyanine compound, a quaterrylene compound, an ammonium compound, an immonium compound, Azo compounds, anthraquinone compounds, porphyrin compounds, pyrrolopyrrole compounds, oxonol compounds, ketonium compounds, hexaphyrin compounds, or combinations thereof. The organic dye preferably contains a phthalocyanine compound (phthalocyanine dye). Phthalocyanine dyes are excellent in hue, heat resistance, light resistance, and the like. As [A] organic dye, two or more kinds of phthalocyanine dyes may be used, and one kind of phthalocyanine dye and an organic dye other than phthalocyanine dye may be used in combination.

The lower limit of the solubility of the organic dye [A] organic pigment with respect to the main solvent is preferably 2% by mass, more preferably 3% by mass, and even more preferably 5% by mass. In this way, the high solubility of the [A] organic pigment with respect to the main solvent can further reduce the generation of agglomerated foreign matter. In addition, the so-called main solvent refers to the solvent having the largest content in the [D] solvent on a mass basis. In addition, the solubility is a value at 20 ° C and 0.1 MPa, and refers to the concentration of the [A] organic pigment in a solution in which the largest amount of the [A] organic pigment is dissolved in the main solvent, that is, in a saturated solution. (quality%). The solubility of the [A] organic pigment can be achieved by a combination of the [A] organic pigment and a main solvent. The upper limit of the solubility is not particularly limited, and may be, for example, 50% by mass.

As the lower limit of the content (WA) of the [A] organic pigment in the composition, when the total amount of the components other than the [D] solvent is 100% by mass, it is preferably 5% by mass, and more preferably 7% by mass. %. By setting the content of the [A] organic pigment (the content ratio in the solid content) to be greater than the lower limit, it is possible to improve infrared shielding performance in a region close to visible light (for example, 700 nm to 800 nm). On the other hand, the upper limit of the content (WA) is preferably 20% by mass, and more preferably 15% by mass. When the content of the [A] organic pigment (the content ratio in the solid content) is equal to or lower than the above-mentioned upper limit, the generation of aggregated foreign matter can be further suppressed, and visible light transmittance can be improved.

([B] inorganic compound)
[B] An inorganic compound is a component which has an absorption wavelength in the range of 900 nm to 2000 nm in wavelength, and functions as an infrared shielding agent that shields infrared radiation having a longer wavelength. [B] The inorganic compound may be a so-called inorganic pigment. [B] The inorganic compound is usually particulate and is dispersed in the composition.

[B] The inorganic compound is preferably an oxide of a metal or a semimetal (such as silicon). As [B] inorganic oxide, specifically, cesium tungsten oxide, quartz, magnetite, aluminum oxide, titanium dioxide, zirconia, spinel, tin-doped indium oxide, antimony-doped tin oxide, or these The combination. These inorganic compounds may be used singly or in combination of two or more.

As [B] inorganic compound, among these, cesium tungsten oxide is preferable. Cesium tungsten oxide is an infrared shielding agent that has high absorption of infrared rays (especially infrared rays having a wavelength of about 900 nm to 2,000 nm) (that is, high shielding ability to infrared rays) and low absorption to visible light. Therefore, by using cesium tungsten oxide, it is possible to maintain good visible light transmittance of the obtained infrared absorbing film and improve infrared shielding properties.

Cesium tungsten oxide can be represented by the following formula (a), for example.
Cs _x WO _y ... (a)
In the formula (A), 0.001 ≦ x ≦ 1.1. 2.2 ≦ y ≦ 3.0.

When x in the formula (a) is 0.001 or more, infrared rays can be sufficiently shielded. The lower limit of x is preferably 0.01, and more preferably 0.1. On the other hand, when x is 1.1 or less, generation of an impurity phase in cesium tungsten oxide can be more reliably avoided. The upper limit of x is preferably 1 and more preferably 0.5.

When y in the formula (a) is 2.2 or more, the chemical stability as a material can be further improved. The lower limit of y is preferably 2.5. On the other hand, when y is 3.0 or less, infrared rays can be sufficiently shielded.

Specific examples of the cesium tungsten oxide represented by the formula (a) include Cs _0.33 WO ₃ and the like.

[B] The inorganic compound is preferably fine particles. The upper limit of the average particle diameter (D50) of the [B] inorganic compound is preferably 500 nm, more preferably 200 nm, still more preferably 50 nm, still more preferably 30 nm, and even more preferably 20 nm. When the average particle diameter is equal to or less than the upper limit, generation of agglomerated foreign matter can be suppressed, and visible light transmittance can be further improved. On the other hand, the average particle diameter of the [B] inorganic compound is usually 1 nm or more and may be 10 nm or more for reasons such as ease of handling during production. The average particle diameter (D50) is a secondary particle diameter in the composition.

[B] An inorganic compound can be synthesized by a conventional method, but can also be obtained as a commercially available product. For example, cesium tungsten oxide can also be obtained as a dispersion of cesium tungsten oxide particles such as "YMF-02" by Sumitomo Metal Mining Corporation.

As the lower limit of the content (WB) of the [B] inorganic compound in the composition, when the total amount of components other than the [D] solvent is set to 100% by mass, it is preferably 1% by mass, and more preferably 3% by mass. %. By setting the content of the [B] inorganic compound (the content ratio in the solid content) to be above the lower limit, it is possible to further increase the wavelength with a longer wavelength (for example, 900 nm or more) by using it in combination with a dielectric multilayer film Infrared shielding performance. On the other hand, the upper limit of the content (WB) is preferably 20% by mass, and more preferably 10% by mass. By setting the content of the [B] inorganic compound (the content ratio in the solid content) to be equal to or less than the upper limit described above, the generation of agglomerated foreign matter can be further suppressed.

The lower limit of the ratio (WA / WB) of the content of [A] organic pigment (WA) to the content of [B] inorganic compound (WB) is preferably 0.2, more preferably 0.3, even more preferably 0.5, and more It is preferably 1.0, and sometimes even more preferably 1.5. On the other hand, the upper limit of the ratio (WA / WB) is preferably 10, more preferably 8, even more preferably 5, sometimes even more preferably 3, and even more preferably 1.5. By setting the ratio (WA / WB) within the above range, the balance between the content of [A] organic pigment (WA) and the content of [B] inorganic compound (WB) becomes better, and it can be fully utilized. Effects of the present invention. Specifically, by setting the ratio (WA / WB) to be greater than or equal to the lower limit, visible light transmittance tends to be improved. On the other hand, by setting the ratio (WA / WB) to be equal to or lower than the upper limit described above, there is a tendency that the shielding properties of infrared rays close to the visible light region are improved.

Particularly preferably, the content (WA) of the [A] organic pigment is 5 mass% to 20 mass%, and the ratio of the content of the [A] organic pigment (WA) to the content of the [B] inorganic compound (WB) ( WA / WB) is 0.2 or more and 10 or less. In this case, using a sufficient amount of [A] organic pigment, the infrared rays in the region near the visible light are more fully shielded, and the content of the [B] inorganic compound is moderately suppressed, so the generation of condensed foreign matter can be further reduced. . In addition, the infrared absorbing ability of an infrared shielding filter of a solid-state imaging element when used in combination with a dielectric multilayer film is further improved. The more preferable ranges of the content (WA) and the ratio (WA / WB) of the organic pigment [A] are as described above.

([C] Binder Resin)
[C] The binder resin is a component serving as a matrix in the formed infrared absorbing film. [C] The binder resin is not particularly limited, but a resin having an acidic functional group such as a carboxyl group or a phenolic hydroxyl group is preferred. Among these, a polymer having a carboxyl group (hereinafter, also referred to as a “carboxyl-containing polymer”) is preferred. Examples of the carboxyl group-containing polymer include an ethylenically unsaturated monomer having one or more carboxyl groups (hereinafter also referred to as "unsaturated monomer (1)") and other copolymerizable ethylenically unsaturated monomers ( Hereinafter, it is also referred to as a copolymer of "unsaturated monomer (2)".

Examples of the unsaturated monomer (1) include (meth) acrylic acid, maleic acid, maleic anhydride, succinic acid mono [2- (meth) acryloxyethyl] ester, and ω- Carboxyl polycaprolactone mono (meth) acrylate, p-vinyl benzoic acid and the like.

Examples of the unsaturated monomer (2) include:
Maleimide compounds such as N-phenylmaleimide, N-cyclohexylmaleimide, etc .;
Aromatic vinyl compounds such as styrene, α-methylstyrene, p-hydroxystyrene, p-hydroxy-α-methylstyrene, p-vinylbenzyl glycidyl ether, fluorene, etc .;
Methyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, allyl (meth) acrylate , Benzyl (meth) acrylate, polyethylene glycol (degree of polymerization 2 to 10) methyl ether (meth) acrylate, polypropylene glycol (degree of polymerization 2 to 10) methyl ether (meth) acrylate, polyethylene glycol Alcohol (degree of polymerization 2 to 10) mono (meth) acrylate, polypropylene glycol (degree of polymerization 2 to 10) mono (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate , Tricyclo [5.2.1.0 ^2,6 ] decane-8-yl (meth) acrylate, dicyclopentenyl (meth) acrylate, glycerol mono (meth) acrylate, (meth) acrylic acid- 4-hydroxyphenyl ester, ethylene oxide modified (meth) acrylate of p-cumylphenol, glycidyl (meth) acrylate, -3,4-epoxycyclohexyl (meth) acrylate Methyl ester, 3-[(meth) propenyloxymethyl] oxetane, 3-[(meth) propenyloxymethyl] -3-ethyloxetane, etc. ( (Meth) acrylates;
Cyclohexyl vinyl ether, isobornyl vinyl ether, tricyclic [5.2.1.0 ^2,6 ] decane-8-yl vinyl ether, pentacyclopentadecyl vinyl ether, 3- (vinyloxymethyl) Group) vinyl ethers such as 3-ethyloxetane;
Polystyrene, polymethyl (meth) acrylate, poly-n-butyl (meth) acrylate, polysiloxane is equivalent to a macromonomer having a mono (meth) acrylfluorene group at the end of a polymer molecular chain, and the like.

The unsaturated monomer (2) is also preferably a monomer that provides a structural unit having a polymerizable unsaturated bond. By using such a monomer, a polymer having a polymerizable unsaturated bond can be obtained.

Examples of the monomer that provides a structural unit having a polymerizable unsaturated bond include:
Ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (methyl) ) Acrylate, tripropylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediene Di (meth) acrylate compounds such as alcohol di (meth) acrylate, neopentyl glycol di (meth) acrylate, tripropylene glycol diacrylate, etc .;
Tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, etc. Ester compound
Tetra (meth) acrylate compounds such as pentaerythritol tetra (meth) acrylate;
Penta (meth) acrylate compounds such as dipentaerythritol penta (meth) acrylate and the like.

The structural unit having a polymerizable unsaturated bond may have a specific group possessed by the structural unit in the polymer, a group having a reaction with the specific group, and a (meth) acrylfluorenyl group or a vinyl group. The compounds are obtained by reaction. For example, a structural unit having a polymerizable unsaturated bond can be introduced by the following methods: (1) a method of reacting a polymer having a carboxyl group with an unsaturated compound containing an epoxy group, and the like; (2) making an epoxy group having an epoxy group; A method for reacting a polymer with (meth) acrylic acid, etc .; (3) A method for reacting a polymer having a hydroxyl group with a (meth) acrylate or vinyl compound having an isocyanate group; (4) A method A method of reacting a polymer having an acid anhydride site with (meth) acrylic acid and the like.

As the unsaturated monomer (2), a monomer including a structural unit including a ring structure is also preferable. Examples of such a monomer that provides a structural unit including a ring structure include a maleimide compound, an aromatic vinyl compound, a cycloalkyl vinyl ether, and a cycloalkyl group among the unsaturated monomers exemplified above. The (meth) acrylate is preferably a maleimide compound.

Moreover, as [C] binder resin, polysiloxane etc. can also be used.

The lower limit of the glass transition temperature (Tg) of the [C] binder resin is preferably -10 ° C, and more preferably 30 ° C. On the other hand, the upper limit of the glass transition temperature is preferably 250%, and more preferably 200%. When the glass transition temperature of the [C] binder resin is within the above range, generation of agglomerated foreign matter or the like can be further reduced.

The lower limit of the polystyrene-equivalent weight average molecular weight (Mw) obtained by the gel permeation chromatography (GPC) as the [C] binder resin is preferably 500, more preferably 1,000. On the other hand, the upper limit of the polystyrene-equivalent weight average molecular weight (Mw) is preferably 50,000, and more preferably 30,000. When the polystyrene-equivalent weight average molecular weight (Mw) of the [C] binder resin is within the above range, generation of agglomerated foreign matter and the like can be further reduced.

As the [C] binder resin, it is also preferable to use a resin that functions as a dispersant for the [B] inorganic compound (hereinafter, also referred to as a “dispersant”). When a dispersion medium is used, the dispersibility of the [B] inorganic compound and the like is improved, and the generation of aggregated foreign matter can be further reduced.

The lower limit of the amine value of the dispersant is preferably 100 mgKOH / g, and more preferably 110 mgKOH / g. On the other hand, the upper limit of the amine value is preferably 200 mgKOH / g, and more preferably 150 mgKOH / g. By using the dispersant having the amine value, the dispersibility of the [B] inorganic compound is improved, and the generation of aggregated foreign matter can be further reduced, and the visible light transmittance or infrared shielding property of the obtained infrared absorbing film is further improved. The "amine value" is the number of mg of KOH equivalent to HCl required to neutralize 1 g of the solid content of the dispersant. When multiple dispersants are used, the amine value is a weighted average.

The dispersant is preferably a block copolymer. The block copolymer is preferably a block copolymer having an A block containing a functional group containing a nitrogen atom and a B block having a solvent affinity. The nitrogen atom-containing functional group of the A block shows good adsorptivity to the [B] inorganic compound. Therefore, by using a block copolymer having an A block and a B block, the dispersibility of the [B] inorganic compound can be further improved.

The A block preferably has a structural unit represented by the following formula (1), for example.

[Chemical 1]

In formula (1), X is a divalent linking group. R ¹ is a hydrogen atom or a methyl group. R ² and R ³ are each independently a hydrogen atom, or a chain-like or cyclic hydrocarbon group which may have a substituent, or R ² and R ³ are bonded to each other and form a ring structure together with these bonded nitrogen atoms.

Examples of the X include a methylene group, an alkylene group having 2 to 10 carbon atoms, an arylene group, a group represented by -CONH-R ⁷ -(*), and -COO-R ⁸ -(*). Expressed bases and so on. R ⁷ and R ⁸ are each independently a methylene group, an alkylene group having 2 to 10 carbon atoms, or an alkyleneoxy group 2 to 10 carbon atoms. (*) Indicates a bonding site with N. X is preferably a group represented by -COO-R ^8- , and R ^{8 is} preferably an alkylene group having 2 to 6 carbon atoms.

R ² and R ^{3 are} preferably a chain hydrocarbon group, more preferably a chain hydrocarbon group having 1 to 5 carbon atoms, and even more preferably a methyl group, an ethyl group, and a propyl group.

Examples of the monomer that provides the structural unit represented by the formula (1) include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, and (methyl) Dimethylaminopropyl acrylate, diethylaminopropyl (meth) acrylate, and the like.

The A block may include a structural unit other than the structural unit represented by the formula (1). The content ratio of the A block in the block copolymer is preferably, for example, 30% by mass or more and 70% by mass or less.

The B block preferably has a structural unit represented by the following formula (2), for example.

[Chemical 2]

In formula (2), R ^{4 is} each independently an alkylene group having 2 to 4 carbon atoms. R ⁵ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. R ⁶ is a hydrogen atom or a methyl group. n is an integer from 1 to 150.

R ^{4 is} preferably ethylene or methyl. R ^{5 is} preferably methyl, ethyl, propyl, or butyl. The upper limit of n is preferably 20, more preferably 10, and even more preferably 5.

Examples of the monomer that provides the structural unit represented by the formula (2) include polyethylene glycol (n = 1 to 5) methyl ether (meth) acrylate, and polyethylene glycol (n = 1 to 5). ) Ether (meth) acrylate, polyethylene glycol (n = 1 to 5) propyl ether (meth) acrylate, polypropylene glycol (n = 1 to 5) methyl ether (meth) acrylate, polypropylene glycol ( n = 1 to 5) diethyl ether (meth) acrylate, polypropylene glycol (n = 1 to 5) propyl ether (meth) acrylate, and the like.

The B block may include a structural unit other than the structural unit represented by the formula (2). As another structural unit which a B block can contain, the structural unit derived from a (meth) acrylate is mentioned. Specifically, as a monomer which provides another structural unit, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, ( Butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, phenyl (meth) acrylate, cyclohexyl (meth) acrylate, and the like.

The content ratio of the B block in the block copolymer is preferably, for example, 30% by mass or more and 70% by mass or less.

The lower limit of the average molecular weight of the block copolymer is, for example, 3,000, and preferably 6,000. On the other hand, the upper limit is, for example, 30,000, and preferably 20,000.

The block copolymer can be synthesized by a conventionally known method. Moreover, a commercial product can also be used for a block copolymer and other dispersing agents.

When the content of the [C] binder resin in the composition is 100% by mass based on the total amount of components other than the [D] solvent, it is preferably 10% by mass or more and 50% by mass or less.

([D] Solvent)
[D] The solvent can be appropriately selected and used as long as it disperses or dissolves other components and does not react with these components and has a moderate volatility. [D] The solvent may be used singly or in combination of two or more kinds. In the case where the [D] solvent contains one solvent, the solvent is the main solvent. In addition, when two or more solvents are used in combination, the solvent having the highest content on a mass basis is the main solvent.

Examples of the [D] solvent include:
Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol mono-n-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol Mono-n-propyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono- (Poly) alkanediol monomers such as n-butyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-n-butyl ether, tripropylene glycol monomethyl ether, and tripropylene glycol monoethyl ether. Alkyl ethers
Alkyl lactates such as methyl lactate and ethyl lactate;
(Cyclo) alkyl alcohols such as methanol, ethanol, propanol, butanol, isopropanol, isobutanol, tertiary butanol, octanol, 2-ethylhexanol, cyclohexanol;
Ketone alcohols such as diacetone alcohol;
Ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether (Poly) alkanediol monoalkane such as diethyl ether acetate, dipropylene glycol monomethyl ether acetate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, etc. Ether ether acetates;
Other ethers such as diethylene glycol dimethyl ether, diethylene glycol methyl ether, diethylene glycol diethyl ether, tetrahydrofuran;
Ketones such as methyl ethyl ketone, 2-heptanone, 3-heptanone and other chain ketones, cyclic ketones such as cyclopentanone and cyclohexanone;
Diacetates such as propylene glycol diacetate, 1,3-butanediol diacetate, and 1,6-hexanediol diacetate;
Methyl 3-methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, ethyl ethoxyacetate, 3-methyl Alkoxycarboxylic acid esters such as methyl-3-methoxybutylpropionate;
Ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, n-amyl formate, isoamyl acetate, n-butyl propionate, ethyl butyrate, n-propyl butyrate , Isopropyl butyrate, n-butyl butyrate, methyl pyruvate, ethyl pyruvate, n-propyl pyruvate, methyl ethyl acetate, ethyl acetate, ethyl 2-oxobutyrate, etc. Other esters;
Aromatic hydrocarbons such as toluene and xylene;
N, N-dimethylformamide, N, N-dimethylacetamidamine, N-methylpyrrolidone, and the like amidines and lactams.

Among these, ketones are preferred, and cyclic ketones are more preferred.

The content of the [D] solvent in the infrared absorbing composition is not particularly limited. The lower limit of the solid content concentration (total concentration of each component other than the [D] solvent) in the infrared absorbing composition is preferably 5% by mass, and more preferably 10% by mass. On the other hand, the upper limit of the solid content concentration is preferably 50% by mass, and more preferably 40% by mass. By setting the solid content concentration within the above range, dispersibility, stability, coatability, and the like become better.

(Polymerizable compound)
The resin composition may further include a polymerizable compound. When the composition contains a polymerizable compound, it can exhibit good curability and good heat resistance of the obtained infrared absorbing film. The polymerizable compound refers to a compound having two or more polymerizable groups. However, the polymerizable compound does not include a [C] binder resin. Examples of the polymerizable group include an ethylenically unsaturated group, an oxetanyl group, an oxetanyl group, and an N-alkoxymethylamino group. The polymerizable compound is preferably a compound having two or more (meth) acrylfluorenyl groups and a compound having two or more N-alkoxymethylamino groups, and more preferably two or more ( (Meth) acrylfluorenyl compounds. The polymerizable compound may be used singly or in combination of two or more kinds.

Examples of the compound having two or more (meth) acrylfluorenyl groups include polyfunctional (meth) acrylates, which are reactants of an aliphatic polyhydroxy compound and (meth) acrylic acid, and modified with caprolactone. Polyfunctional (meth) acrylate, polyfunctional (meth) acrylate modified by alkylene oxide, polyfunctional amine group as a reactant of hydroxyl (meth) acrylate and polyfunctional isocyanate, etc. Polyfunctional (meth) acrylates having a carboxyl group, such as formate (meth) acrylate, a reactant of a (meth) acrylate having a hydroxyl group and an acid anhydride, and the like.

Here, examples of the aliphatic polyhydroxy compound include divalent aliphatic polyhydroxy compounds such as ethylene glycol, propylene glycol, polyethylene glycol, and polypropylene glycol, or glycerol, trimethylolpropane, pentaerythritol, and the like. Trivalent or higher aliphatic polyhydroxy compounds such as dipentaerythritol. Examples of the (meth) acrylate having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, trimethylolpropane di (meth) acrylate, and pentaerythritol tri (meth) acrylate. , Dipentaerythritol penta (meth) acrylate, glycerol dimethacrylate and the like. Examples of the polyfunctional isocyanate include toluene diisocyanate, hexamethylene diisocyanate, diphenylmethylene diisocyanate, isophorone diisocyanate, and the like. Examples of the acid anhydride include diprotic anhydrides such as succinic anhydride, maleic anhydride, glutaric anhydride, itaconic anhydride, phthalic anhydride, and hexahydrophthalic anhydride, or pyromellitic dianhydride. Tetraprotic acid dianhydride such as biphenyltetracarboxylic dianhydride, benzophenone tetracarboxylic dianhydride and the like.

Specific examples of the compound having two or more (meth) acrylfluorenyl groups include, for example, ω-carboxy polycaprolactone mono (meth) acrylate, ethylene glycol (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate Ester, polypropylene glycol di (meth) acrylate, bisphenoxyethanol, di (meth) acrylate, dimethylol tricyclodecane di (meth) acrylate, 2-hydroxy-3- (formaldehyde) Propyl) propenyloxypropylmethacrylate, 2- (2'-vinyloxyethoxy) ethyl (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (Meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tris (2- (meth) acrylic acid ethoxyethyl) ) Phosphate ester, ethylene oxide modified dipentaerythritol hexaacrylate, succinic acid modified pentaerythritol triacrylate, urethane (meth) acrylate compound, and the like.

Among the compounds having two or more (meth) acrylfluorenyl groups, a polyfunctional (meth) acrylate is preferable, and a polyfunctional having three or more (meth) acrylfluorene groups is more preferable. (Meth) acrylate. Specifically, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate are preferable.

Examples of the compound having two or more N-alkoxymethylamino groups include compounds having a melamine structure, a benzoguanamine structure, and a urea structure. Specific examples of the compound having two or more N-alkoxymethylamino groups include N, N, N ', N', N '', N ''-hexa (alkoxymethyl) Melamine, N, N, N ', N'-tetrakis (alkoxymethyl) benzoguanamine, N, N, N', N'-tetrakis (alkoxymethyl) acetylene urea and the like.

As the lower limit of the content of the polymerizable compound in the composition, when the total amount of components other than the [D] solvent is 100% by mass, it is preferably 5% by mass, more preferably 10% by mass, and even more preferably It is 20% by mass. On the other hand, the upper limit of the content is preferably 60% by mass, and more preferably 50% by mass.

(Polymerization initiator)
The composition may further include a polymerization initiator. The polymerization initiator is a component that starts a polymerization reaction of a polymerizable compound. Examples of the polymerization initiator include a photopolymerization initiator and a thermal polymerization initiator, and a photopolymerization initiator is preferred. This makes it possible to impart sensitivity (radiation sensitivity) to the composition. The photopolymerization initiator refers to a compound that generates an active species that initiates polymerization of a polymerizable compound by exposure to radiation such as visible light, ultraviolet rays, extreme ultraviolet rays, electron beams, and X-rays. The polymerization initiator may be used singly or in combination of two or more.

Examples of the polymerization initiator include thioxanthone-based compounds, acetophenone-based compounds, biimidazole-based compounds, triazine-based compounds, O-fluorenyl oxime-based compounds, onium salt-based compounds, benzoin-based compounds, and A benzophenone-based compound, an α-diketone-based compound, a polynuclear quinone-based compound, a diazo-based compound, a fluorenimine sulfonate-based compound, an onium salt-based compound, and the like. Among these, a thioxanthone-based compound, an acetophenone-based compound, a biimidazole-based compound, a triazine-based compound, and an O-fluorenyl oxime-based compound are preferred, and an O-fluorenyl oxime-based compound is more preferred.

Examples of the thioxanthone-based compound include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4 -Dichlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, and the like.

Examples of the acetophenone-based compound include 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinylpropane-1-one and 2-benzyl-2-dimethyl Amino-1- (4-morpholinylphenyl) butane-1-one, 2- (4-methylbenzyl) -2- (dimethylamino) -1- (4-morpholinyl Phenyl) butane-1-one and the like.

Examples of the biimidazole-based compound include 2,2'-bis (2-chlorophenyl) -4,4 ', 5,5'-tetraphenyl-1,2'-biimidazole and 2,2'- Bis (2,4-dichlorophenyl) -4,4 ', 5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis (2,4,6-trichlorobenzene) Group) -4,4 ', 5,5'-tetraphenyl-1,2'-biimidazole and the like.

When a biimidazole-based compound is used, a hydrogen donor is preferably used in combination in terms of improving sensitivity. The "hydrogen donor" as used herein means a compound capable of supplying a hydrogen atom to a radical generated from a biimidazole-based compound by exposure. Examples of the hydrogen donor include thiol-based hydrogen donors such as 2-mercaptobenzothiazole and 2-mercaptobenzoxazole; 4,4'-bis (dimethylamino) benzophenone; 4 , 4'-bis (diethylamino) benzophenone and other amine-based hydrogen donors.

Examples of the triazine-based compound include compounds described in paragraphs [0063] to [0065] of Japanese Patent Laid-Open No. 57-6096 and Japanese Patent Laid-Open No. 2003-238898.

Examples of the O-fluorenyl oxime-based compound include 1,2-octanedione-1- [4- (phenylthio) phenyl] -2- (O-benzylidene oxime), and ethyl ketone-1 -[9-ethyl-6- (2-methylbenzylidene) -9H-carbazol-3-yl] -1- (O-ethylamidoxime), ethyl ketone-1- [9-ethyl -6- (2-methyl-4-tetrahydrofurylmethoxybenzyl) -9H-carbazol-3-yl] -1- (O-ethylamidoxime), ethyl ketone-1- [ 9-ethyl-6- {2-methyl-4- (2,2-dimethyl-1,3-dioxolyl) methoxybenzyl} -9H-carbazole-3 -Yl] -1- (O-acetylamoxime) and the like. As commercially available products of O-fluorenyl oxime-based compounds, NCI-831, NCI-930 (the above are manufactured by ADEKA), OXE-03, OXE-04 (the above are BASF ( BASF).

When a photopolymerization initiator is used, a sensitizer may be used in combination. Examples of the sensitizer include 4,4'-bis (dimethylamino) benzophenone, 4,4'-bis (diethylamino) benzophenone, and 4-bis Ethylaminoacetophenone, 4-dimethylaminophenylacetone, ethyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2,5 -Bis (4-diethylaminobenzylidene) cyclohexanone, 7-diethylamino-3- (4-diethylaminobenzyl) coumarin, 4- (diethyl Aminoamino) chalcone and the like.

The lower limit of the content of the polymerization initiator is preferably 1 part by mass, and more preferably 5 parts by mass with respect to 100 parts by mass of the polymerizable compound. On the other hand, the upper limit of the content is preferably 100 parts by mass, and more preferably 40 parts by mass.

(additive)
The composition may optionally contain various other additives.

Examples of the additives include surfactants, adhesion promoters, antioxidants, ultraviolet absorbers, anticoagulants, residue improvers, developability improvers, thiol compounds, and dispersants other than resins.

Examples of the surfactant include a fluorine surfactant, a silicone surfactant, and the like. When the content of the surfactant in the composition is 100% by mass based on the total amount of components other than the [D] solvent, it may be, for example, 0.01% by mass or more and 5% by mass or less.

Examples of the adhesion promoter include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (2-methoxyethoxy) silane, and N- (2-aminoethyl) -3. -Aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-shrink Glyceryloxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-chloropropane Methylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and the like.

Examples of the antioxidant include 2,2-thiobis (4-methyl-6-tert-butylphenol), 2,6-di-tert-butylphenol, and pentaerythritol tetra [3- (3,5 -Di-third-butyl-4-hydroxyphenyl) propionate], 3,9-bis [2- [3- (3-third-butyl-4-hydroxy-5-methylphenyl)- Propyloxy] -1,1-dimethylethyl] -2,4,8,10-tetraoxa-spiro [5.5] undecane, thiodiethylenebis [3- (3,5- Di-third butyl-4-hydroxyphenyl) propionate] and the like. When the content of the antioxidant in the composition is 100% by mass based on the total amount of components other than the [D] solvent, it may be, for example, 0.01% by mass or more and 5% by mass or less.

Examples of the ultraviolet absorber include 2- (3-thirdbutyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, and alkoxybenzophenones.

Examples of the anticoagulant include sodium polyacrylate.

Examples of the residue improving agent include malonic acid, adipic acid, itaconic acid, citraconic acid, fumaric acid, mesaconic acid, 2-aminoethanol, 3-amino-1-propanol, 5-amino-1-pentanol, 3-amino-1,2-propanediol, 2-amino-1,3-propanediol, 4-amino-1,2-butanediol, and the like.

Examples of the developability improving agent include: [2- (meth) acryloxyethyl] succinate, [2- (meth) acryloxyethyl] phthalate, and ω -Agents such as carboxypolycaprolactone mono (meth) acrylate and the like.

The thiol-based compound is a compound having a thiol group (thiol group). The thiol-based compound is preferably a compound having two or more mercapto groups in one molecule. When the content of the thiol-based compound in the composition is 100% by mass based on the total amount of components other than the [D] solvent, it may be, for example, 0.1% by mass or more and 5% by mass or less. By setting the content of the thiol-based compound to the above range, the curability and the like can be further improved.

(Preparation)
The method for preparing the composition is not particularly limited, and it can be prepared by mixing the components. This composition can be filtered to remove aggregates as necessary.

(use)
This infrared absorbing composition can be preferably used as a material for forming an infrared absorbing film. In particular, the infrared absorbing composition can be more preferably used as a material for forming an infrared absorbing film of an infrared shielding filter (more preferably, a near infrared shielding filter) as a solid-state imaging element.

(Method for forming infrared absorbing film)
An example of a method for forming an infrared absorbing film using the infrared absorbing composition is the following method, which includes:
A step of forming a coating film on one side of the substrate (step 1);
A step of irradiating at least a part of the coating film with radiation (step 2); and a step of developing the coating film after irradiation with radiation (step 3),
The coating film is formed using the infrared absorbing composition.

(step 1)
In step 1, a coating film is formed on one surface side of a substrate (support) using the composition. Examples of the substrate include a glass substrate and a synthetic resin substrate. The shape of the substrate is not limited to a plate shape. When an infrared absorbing film is incorporated in a solid-state imaging element described later, a transparent substrate, a microlens, a color filter, and the like as constituent elements of the solid-state imaging element may correspond to the substrate.

The formation of the coating film can be usually performed by coating the composition. The coating can be performed by a suitable coating method such as a spray method, a roll coating method, a spin coating method (spin coating method), a slot die coating method (slit coating method), or a bar coating method.

After coating, a pre-baking is performed to evaporate the solvent, thereby forming a coating film. The conditions for the heating and drying in the pre-baking are, for example, about 70 ° C. to 110 ° C., about 1 minute to about 10 minutes.

(Step 2)
In step 2, at least a part of the coating film is irradiated with radiation. Examples of the radiation light source used in the exposure of the coating film include xenon lamps, halogen lamps, tungsten lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halogen lamps, medium-pressure mercury lamps, and low-pressure mercury lamps, or argon ion lightning. Laser, yttrium aluminum garnet (YAG) laser, XeCl excimer laser, nitrogen laser and other laser light sources. As an exposure light source, an ultraviolet light emitting diode (LED) can also be used. The radiation having a wavelength in the range of 190 nm to 450 nm is preferred. The radiation exposure amount is usually about 10 J / m ² or more and about 50,000 J / m ² or less.

(Step 3)
In step 3, the coating film after radiation irradiation is developed. The developer is usually an alkaline developer or an organic solvent developer. Furthermore, after development, it is usually washed with water.

As the alkaline developing solution, for example, sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide (TMAH), choline, 1,8-diazabicyclo- [5.4. 0] -7-undecene, 1,5-diazabicyclo- [4.3.0] -5-nonene and other aqueous solutions. To the alkaline developer, for example, an appropriate amount of a water-soluble organic solvent such as methanol, ethanol, or a surfactant may be added.

As the organic solvent developer, acetone, methyl ethyl ketone, 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3 -Ketones such as hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone; propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butene acetate Ester, isoamyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isoamyl formate, methyl valerate, methyl pentenoate, methyl butenoate, ethyl butenoate Ester, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, amyl lactate, isoamyl lactate Esters, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenyl acetate, benzyl formate, benzene formate Esters such as methyl ethyl, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, and 2-phenylethyl acetate.

As the development processing method, a spray development method, a spray development method, a dip development method, a puddle development method, and the like can be applied. The development conditions are performed at normal temperature for 5 seconds to 300 seconds.

The non-exposed portion of the coating film is dissolved and removed by the development. Thereafter, by performing post-baking as necessary, an infrared shielding film patterned into a predetermined shape can be obtained. The post-baking conditions are usually about 180 ° C. to 280 ° C., about 1 minute to about 60 minutes.

When the composition does not contain a polymerizable compound and a polymerization initiator, etc., unlike the formation method described above, curing treatment such as exposure may not be performed. In addition, the development process may not be performed, and in this case, an unpatterned infrared absorbing film may be formed.

(Infrared absorbing film)
The use of the infrared absorbing film is not particularly limited, and it can be preferably used as an infrared shielding filter for a solid-state imaging element. In particular, the infrared absorbing film is incorporated into a solid-state imaging element together with a dielectric multilayer film, and can better function as an infrared shielding filter.

The infrared absorbing film can be used by being laminated on the surface of a transparent substrate. As the transparent substrate, glass, transparent resin, or the like can be used. Examples of the transparent resin include polycarbonate, polyester, aromatic polyimide, polyimide, imine, and polyimide. In addition, as described later, the infrared absorbing film may be directly laminated on a member of a solid-state imaging element.

When the infrared absorbing film is used in a solid-state imaging device, the lower limit of the infrared absorbing film is usually 0.5 μm, and preferably 1 μm. On the other hand, the upper limit of the average film thickness is usually 5 μm, and preferably 3 μm. When the average film thickness of the infrared absorbing film is within the above range, the balance between visible light transmittance and infrared shielding properties becomes better.

As described above, the infrared absorbing film formed of the infrared absorbing composition has a shorter infrared shielding property on the shorter wavelength side, and has a lower infrared shielding property on the longer wavelength side. That is, the infrared absorbing film also satisfies the formula (I).

In addition, the lower limit of the average transmittance of the infrared absorbing film at a wavelength of 430 nm or more and 580 nm or less is preferably 75%, more preferably 80%. The upper limit of the average transmittance may be, for example, 95% or 90%. The lower limit of the average transmittance of the infrared absorbing film at a wavelength of 700 nm to 800 nm is preferably less than 15%, more preferably less than 12%, and even more preferably less than 10%. The lower limit of the average transmittance may be, for example, 1% or 5%. The lower limit of the average transmittance of the infrared absorbing film above the wavelength of 801 nm to 1200 nm is preferably less than 80%, more preferably less than 50%. The lower limit of the average transmittance may be, for example, 10% or 30%.

(Solid-state image sensor)
Hereinafter, a solid-state imaging element including the infrared absorbing film and a dielectric multilayer film will be described. The infrared absorbing film and the dielectric multilayer film function well as an infrared shielding filter by virtue of the infrared absorbing ability of the both.

A solid-state imaging element usually has a structure in which a plurality of layers of photodiodes, a color filter, and a microlens are stacked in this order. A planarizing layer may be provided between these layers. In a solid-state imaging device, light is incident from the microlens side. The incident light passes through the microlenses and color filters and reaches the photodiode. The color filter is configured, for example, in each of the R (red), G (green), and B (blue) filters so that only light in a specific wavelength range is transmitted.

The infrared absorbing film formed of the infrared absorbing composition has a higher infrared shielding property on the shorter wavelength side, while the infrared shielding property on the longer wavelength side is lower. As the dielectric multilayer film, it is preferable to use an optical characteristic having a low infrared shielding property on the short wavelength side and a high infrared shielding property on the long wavelength side as the dielectric multilayer film. The dielectric multilayer film preferably satisfies the following formula (i).
x <y ≦ z / 0.95 ... (i)
(In formula (i), x is an average value of the absorbance of a dielectric multilayer film in a range of wavelengths from 700 nm to 800 nm; y is a dielectric in a range of wavelengths from 800 nm to 900 nm The average value of the absorbance of the bulk multilayer film; z is the average value of the absorbance of the dielectric multilayer film in the range of wavelengths from 900 nm to 1200 nm.)

The dielectric multilayer film can be produced by a method described in, for example, Japanese Patent Laid-Open No. 2016-146619.

By using such a dielectric multilayer film in combination with the infrared absorbing film, it is possible to reduce the incidence angle dependency that can be generated in the dielectric multilayer film, and to exert a good infrared absorption ability in a wide wavelength range. Regarding the relationship between x and y, it is preferably x <y / 2, and more preferably x <y / 3. In addition, x> y / 100 is preferred, and x> y / 10 is preferred. Regarding the relationship between x and z, it is preferably x <z / 2, and more preferably x <z / 3. In addition, x> z / 100 is preferred, and x> z / 10 is preferred.

In addition, as the upper limit of the x (the average value of the absorbance of the dielectric multilayer film in a range of 700 nm to 800 nm), 1.2 is preferred, and 1.15 is more preferred. The upper limit of the average value of the absorbance in the visible light region (wavelength 430 nm to 630 nm) of the dielectric multilayer film is preferably 0.03, and more preferably 0.02. In this case, in the dielectric multilayer film, the visible light transmittance is improved, and the incident angle dependency can be further reduced.

The infrared absorbing film and the dielectric multilayer film may be integrated into a solid-state imaging element, or may be separately incorporated into a solid-state imaging element. In the case where the infrared absorbing film and the dielectric multilayer film are incorporated into a solid-state imaging element independently, there are advantages such as an increase in design freedom, suppression of multiple reflections, and reduction in thickness. On the other hand, when the infrared absorbing film and the dielectric multilayer film are integrated, there is an advantage that productivity is improved when a solid-state imaging element is assembled.

The infrared absorbing film and the dielectric multilayer film may be arranged on the outer surface side of the microlenses of a solid-state imaging element, between the microlenses and a color filter, between the color filter and a photodiode, and the like. Further, for example, another layer (a flattening layer, etc.) may be further provided between the infrared absorbing film and a microlens, a color filter, a photodiode, or the like.

The solid-state imaging device can be effectively used in digital still cameras, mobile phone cameras, digital video cameras, PC cameras, surveillance cameras, automotive cameras, portable information terminals, computers, video games, medical equipment, etc.
[Example]

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples.

<Synthesis example 1>
An organic pigment (A-1) (maximum absorption wavelength: 735 nm) as a phthalocyanine dye represented by the following formula was synthesized along Scheme 1 below. As a starting material, 1,2-dicyano-3,6-bis (4-methoxybutyl) benzene (R = methyl, X = hydrogen atom, n = 4) was used. As "1. base", lithium pentoxide (solid lithium and pentane-1-ol) was used, and as "2. acid", glacial acetic acid was used. In addition, as a salt providing M ²⁺ , a vanadyl salt is used.

[Chemical 3]

[Chemical 4]

<Synthesis example 2>
Using the method described in paragraphs [0020] to [0025] (Example 1) of Japanese Patent Laid-Open No. 05-25177, an organic pigment (A-2) as a phthalocyanine dye represented by the following formula (maximum absorption) 700 nm).

[Chemical 5]

<Synthesis example 3>
An inorganic compound (B-1) as a powder of cesium tungsten oxide (Cs _0.33 WO ₃ ) was synthesized using the method described in paragraph [0113] of Japanese Patent No. 4096205.

<Synthesis example 4>
Synthesized as benzyl methacrylate / styrene / N-phenylmaleimide / -2-hydroxyethyl methacrylate / -2-ethylhexyl methacrylate / methacrylic acid = 14/10 / 12/15/29/20 (mass ratio) copolymer resin (C-2) (acid value: 130 mgKOH / g) to obtain propylene glycol monomethyl ether acetic acid of the binder resin (C-2) Ester 33.9% by mass solution.

Each component used is as follows.
A: Organic pigment
A-1: Organic pigment (A-1) obtained in Synthesis Example 1 (phthalocyanine dye; maximum absorption wavelength 735 nm; solubility with respect to cyclopentanone 10% by mass)
A-2: Organic pigment (A-2) obtained in Synthesis Example 2 (phthalocyanine dye; maximum absorption wavelength 700 nm; solubility with respect to cyclopentanone 10% by mass)
A-3: "FDN-001" by Yamada Chemical Industry Co., Ltd. (phthalocyanine dye; maximum absorption wavelength of 760 nm; solubility over 2% by mass relative to cyclopentanone)
A-4: "FDN-002" of Yamada Chemical Industry Co., Ltd. (phthalocyanine dye; maximum absorption wavelength of 810 nm; solubility over 2% by mass with respect to cyclopentanone)
B: inorganic compound
B-1: Inorganic compound (B-1) obtained in Synthesis Example 3
C: Adhesive resin
C-1: "BYK-LPN6919" by BYK-Chemie (dispersant, solid content = 61% by mass, amine value 120 mgKOH / g)
C-2: Adhesive resin (C-2) obtained in Synthesis Example 4
D: Solvent
D-1: cyclopentanone
E: Polymerizable compound
E-1: "KAYARAD DPHA" by Nippon Kayakusho
F: polymerization initiator
F-1: "NCI-930" (O-fluorenyl oxime compound) from ADEKA
G: Surfactant
G-1: "FTX-218D" (fluorine-based surfactant) from Neos
H: Antioxidant
H-1: BASF's "irganox 1010"
I: Additive "Karenz MT PE1" (Pentaerythritol tetrakis (3-mercaptobutyrate)) of Showa Denko Corporation

[Example 1]
25.00 parts by mass of the inorganic compound (B-1), 13.11 parts by mass of the binder resin (C-1) as a dispersant (solid content amount = 61% by mass), 61.89 parts by mass of the solvent (D-1), and 0.1 mm 2,000 parts by mass of zirconia particles having a diameter of 10 mm were filled in a container and dispersed with a paint shaker, thereby obtaining a dispersion liquid of an inorganic compound (B-1) having an average particle diameter (D50) of 19 nm. In addition, the particle diameter was measured using a light scattering measurement device ("ALV-5000" of German ALV company) by a dynamic light scattering (DLS) method. Each component was added to this dispersion so that it might become a composition as shown in Table 1, and the infrared absorption composition of Example 1 was obtained.

[Example 2 to Example 6, Comparative Example 1 to Comparative Example 5]
Each of the infrared absorbing compositions of Examples 2 to 6 and Comparative Examples 1 to 5 was obtained in the same manner as in Example 1 except that the components were used so as to have the composition described in Table 1.

Each of the obtained infrared absorbing compositions was applied onto a glass substrate by a spin coating method so as to have a predetermined film thickness. Thereafter, heating was performed at 100 ° C. for 120 seconds, and exposure was performed so as to be 1000 mJ / cm ² using an i-ray stepper. Then, an infrared absorbing film having a thickness of 2.0 μm was produced on the glass substrate by heating at 220 ° C. for 300 seconds. The thickness of the film was measured using a stylus-type step meter ("α Step IQ" of Yamato Scientific Co., Ltd.).
Next, using a spectrophotometer ("V-7300" of Japan Spectroscopy Corporation), the transmittance in each wavelength region of the infrared absorption film produced on the glass substrate was measured with a glass substrate contrasted. From the obtained transmission spectrum, X (average of absorbance in a range of wavelengths from 700 nm to 800 nm) and Y (average of absorbance in a range of wavelengths from 800 nm to 900 nm) are determined. , And Z (average absorbance in a range of wavelengths from 900 nm to 1200 nm). These values are shown in Table 1. The transmission spectrum of the infrared absorbing composition of Example 6 is shown in FIG. 1.

[Evaluation]
Evaluation of each infrared absorbing composition was performed by the following method. The results are shown in Table 1.

(Transmittance Evaluation)
Based on the transmission spectrum obtained from each of the infrared absorbing compositions, the transmittance was evaluated by the following evaluation criteria.
(Visible light transmittance)
The average transmittance of 430 nm to 580 nm was calculated and evaluated using the following criteria. When the average transmittance is 70% or less, the sensitivity when used as an infrared shielding filter decreases.
○: 80% or more △: 75% or more and less than 80%
×: less than 75%
(Infrared shielding 1)
The average transmittance of 700 nm to 800 nm was calculated and evaluated using the following criteria. When the average transmittance is 15% or more, when used as an infrared shielding filter, the effect of cutting off noise components is reduced, and the sensitivity is reduced.
○: less than 10%
△: 10% or more and less than 15%
×: 15% or more (infrared shielding 2)
The average transmittance of 801 nm to 1200 nm was calculated and evaluated using the following criteria. When the average transmittance is 80% or more, when used as an infrared shielding filter, the effect of cutting off noise components is reduced, and the sensitivity is reduced.
○: less than 50%
△: 50% or more and less than 80%
×: 80% or more

(Incidence angle dependency)
According to the method described in paragraphs [0177] to [0178] of Japanese Patent Laid-Open No. 2016-146619, an 18-layer layer obtained by alternately stacking silicon oxide layers and titanium oxide layers with optimized thicknesses is obtained A dielectric multilayer film (M1) and a 28-layer dielectric multilayer film (M2) formed by alternately stacking a silicon oxide layer and a titanium oxide layer. FIG. 2 shows a transmission spectrum when the dielectric multilayer film (M1) has an incident angle of 0 ° and a transmission spectrum when the incident angle is 30 °. FIG. 3 shows a transmission spectrum when the dielectric multilayer film (M2) has an incident angle of 0 ° and a transmission spectrum when the incident angle is 30 °.
An infrared absorbing film produced by using the infrared absorbing composition of each of Examples and Comparative Examples by the same method as the transmittance evaluation, and the dielectric multilayer film (M1) or the dielectric In an infrared shielding filter laminated with an electrical multilayer film (M2), the wavelength (half-value wavelength) at which the transmittance of light incident at an incidence angle of 0 ° is calculated to be 50% in the range of 600 nm to 900 nm ), The difference from the half-value wavelength of light incident at an incident angle of 30 °, and evaluated based on the following criteria. The combination with the dielectric multilayer film (M1) is set as the incident angle dependency 1, and the combination with the dielectric multilayer film (M2) is set as the incident angle dependency 2. When the difference between each half-value wavelength is 16 nm or more, color shading or a decrease in sensitivity may occur.
○: less than 5 nm
△: 5 nm or more and less than 16 nm
×: 16 nm or more In addition, FIG. 4 shows an incident angle of an infrared shielding filter obtained by combining an infrared absorbing film obtained from the infrared absorbing composition of Example 6 and a dielectric multilayer film (M2). A transmission spectrum at 0 ° and a transmission spectrum at a wavelength of 350 nm to 750 nm when the incident angle is 30 °. In addition, FIG. 5 shows an infrared shielding filter obtained by combining an infrared absorbing film obtained from the infrared absorbing composition of Comparative Example 2 and a dielectric multilayer film (M2) at an incident angle of 0 °. A transmission spectrum and a transmission spectrum in a wavelength range of 350 nm to 750 nm when the incident angle is 30 °.

(Contrast: foreign matter evaluation)
An infrared absorbing composition was applied on a glass substrate by a spin coating method so as to have a predetermined film thickness. Thereafter, heating was performed at 100 ° C. for 120 seconds, and exposure was performed so as to be 1000 mJ / cm ² using an i-ray stepper. Then, an infrared absorbing film having a thickness of 1.0 μm was produced on the glass substrate by heating at 220 ° C. for 300 seconds. The infrared absorbing film was measured for a contrast value using a contrast meter ("CT-1BA" manufactured by Tubosaka Corporation) and evaluated based on the following criteria.
○: More than 10,000
△: More than 5000 and less than 10,000 ×: Not more than 5000 or cannot be measured

[Table 1]

As shown in Table 1, the visible light transmittance and contrast of the infrared absorbing films obtained from the infrared absorbing compositions of Examples 1 to 6 were high. The reason for this is considered to be that there are few aggregated foreign bodies. In addition, in the infrared absorbing films obtained from the infrared absorbing compositions of Examples 1 to 6, the infrared shielding properties 1 at a wavelength of 700 to 800 nm and the infrared shielding properties 2 at a wavelength of 801 to 1200 nm were also good. . Among the infrared absorbing films obtained from the infrared absorbing compositions of Examples 1 to 6, the infrared shielding properties 1 of wavelengths near 700 to 800 nm, which are particularly close to visible light, were sufficient. ) And the dielectric multilayer film (M2), the incident angle dependency is small.

On the other hand, in the infrared absorbing films obtained from the infrared absorbing compositions of Comparative Examples 1 and 2, the infrared shielding properties 1 at a wavelength near 700 to 800 nm of visible light were low. Therefore, when a dielectric multilayer film (M1) having a high shielding property at a wavelength of 700 nm to 800 nm is to be used to cut off the wavelength of 700 nm to 800 nm, the dielectric multilayer film (M1) is particularly disadvantageous. The incidence angle dependency is large with respect to the wavelength transmittance of 600 nm to 700 nm, so the incidence angle dependency is large. This difference is also shown in the transmission spectra of FIG. 4 and FIG. 5. It can be seen that the incidence angle dependency is large in the case of Comparative Example 2 (FIG. 5). In contrast, in the case of Example 6 (FIG. 4) Incidence angle dependency is small. Furthermore, when the infrared absorbing film obtained from the infrared absorbing composition of Comparative Examples 1 and 2 was combined with a dielectric multilayer film (M2), the wavelengths of 700 nm to 800 nm could not be sufficiently shielded.

Moreover, regarding Comparative Example 3 to Comparative Example 5, it was found that the obtained infrared absorbing film had a large amount of foreign matter and had low visible light transmittance and contrast.
[Industrial availability]

The infrared absorbing composition of the present invention can be preferably used as a forming material for an infrared shielding filter or the like of a solid-state imaging element.

no

FIG. 1 is a transmission spectrum of an infrared absorbing composition of Example 6. FIG.

FIG. 2 is a transmission spectrum of a dielectric multilayer film (M1) used in evaluation of an example.

FIG. 3 is a transmission spectrum of a dielectric multilayer film (M2) used in evaluation of an example.

FIG. 4 is a transmission spectrum of an infrared shielding filter combined with an infrared absorbing film obtained from the infrared absorbing composition of Example 6 and a dielectric multilayer film (M2).

FIG. 5 is a transmission spectrum of an infrared shielding filter combined with an infrared absorbing film obtained from the infrared absorbing composition of Comparative Example 2 and a dielectric multilayer film (M2).

Claims (6)

An infrared absorbing composition containing: Two or more organic pigments with a maximum absorption wavelength in the range of 650 nm to 900 nm; Inorganic compounds with a maximum absorption wavelength in the range from 900 nm to 2000 nm; Adhesive resin; and Solvent, And satisfies the following formula (I), X ＞ Y ≧ 0.80Z ・ ・ ・ (I) In the formula (I), X is an average value of the absorbance of the infrared absorbing composition in a range of wavelengths of 700 nm to 800 nm; Y is a value of the range of wavelengths of 800 nm to 900 nm. An average value of the absorbance of the infrared absorbing composition; Z is an average value of the absorbance of the infrared absorbing composition in a range of a wavelength of 900 nm to 1200 nm. The infrared absorbing composition according to item 1 of the scope of patent application, wherein when the total amount of components other than the solvent is set to 100% by mass, The content (WA) of the organic pigment is 5 mass% or more and 20 mass% or less, The ratio (WA / WB) of the content (WA) of the organic pigment to the content (WB) of the inorganic compound is 0.2 or more and 10 or less. The infrared absorbing composition according to item 1 or item 2 of the patent application scope, wherein the organic pigment comprises a first organic pigment and a second organic pigment, And satisfies the following formula (II), 10 ≦ λ2-λ1 ≦ 120 ... (II) In formula (II), λ1 is the maximum absorption wavelength (nm) of the first organic pigment; λ2 is the maximum absorption wavelength (nm) of the second organic pigment. The infrared absorbing composition according to item 1, 2, or 3 of the scope of patent application, wherein the solvent contains a main solvent, The organic pigment is an organic dye, The solubility of the organic dye with respect to the main solvent is 2% by mass or more. The infrared absorbing composition according to any one of claims 1 to 4 of the scope of patent application, wherein the organic pigment contains a phthalocyanine dye. The infrared absorbing composition according to any one of claims 1 to 5 of the scope of patent application, which is used to form an infrared absorbing film used in a solid-state imaging element.