JP7451951B2 - Coloring compositions, infrared pass filters, filters for solid-state imaging devices, and solid-state imaging devices - Google Patents

Description

The present invention relates to a coloring composition, an infrared pass filter, a filter for a solid-state image sensor, and a solid-state image sensor. More specifically, the present invention relates to a coloring composition composed of a single coloring material suitable for use in an infrared pass filter.

A solid-state image sensor such as a CMOS image sensor or a CCD image sensor includes a photoelectric conversion element that converts the intensity of light into an electrical signal. In addition to the plurality of photoelectric conversion elements, the solid-state image sensor includes a color filter located on the photoelectric conversion element for each color, and an infrared pass filter located on the photoelectric conversion element for infrared (for example, Patent Document 1 ).

The infrared pass filter blocks visible light that can be detected by the infrared photoelectric conversion element, thereby increasing the accuracy of infrared detection by the infrared photoelectric conversion element. The constituent material of the infrared pass filter is, for example, a black coloring material such as a bisbenzofuranone pigment, an azomethine pigment, a perylene pigment, or an azo dye (see, for example, Patent Document 2).

Japanese Patent Application Publication No. 2016-177273 JP 2018-119077 Publication

Incidentally, the infrared pass filter described in the prior art is composed of a mixture of a plurality of coloring materials in order to block visible light. Generally used coloring material molecules have a conjugated system and have associative and aggregating properties. In a coloring composition composed of a mixture of multiple colorants, association and aggregation are promoted more than in a coloring composition composed of a single colorant, and stability over time such as viscosity stability may decrease. , it is desired to develop a coloring composition composed of a single coloring material.

An object of the present invention is to provide a coloring composition composed of a single coloring material and having excellent stability over time, an infrared pass filter, a filter for a solid-state image sensor, and a solid-state image sensor using the same.

In order to solve the above problems, the coloring composition according to the present invention contains a diketopyrrolopyrrole compound represented by the following formula (1).

However, in formula (1), R1, R2, R7, and R8 are a hydrogen atom, a linear alkyl group having 1 or more carbon atoms, or a branched alkyl group having 3 or more carbon atoms. In addition, R3, R4, R5, and R6 are furan or pyrrole, and as represented by the following formula (2), the 3rd and 4th positions are unsubstituted and are bonded to the 2nd and 5th positions. are doing.

It is preferable that the above-mentioned coloring composition contains a polymerizable compound, a binder resin, and a photopolymerization initiator.

The infrared pass filter according to the present invention contains the above coloring composition.

The above infrared pass filter has a colorant concentration in the film of 30 to 60%, and when the film is formed to a thickness of 1.2 μm, the average of light with a wavelength of 400 to 800 nm, which is part of the visible region and near-infrared region, is It is preferable that the transmittance is 30% or less, and the average transmittance of light in the near-infrared region of 900 to 1000 nm is 90% or more.

The filter for a solid-state image sensor according to the present invention includes three color filters, a red filter, a green filter, and a blue filter, located on the light incident side with respect to the first photoelectric conversion element, and a second photoelectric conversion element. On the other hand, the infrared pass filter described above is located on the light incident side.

Preferably, the solid-state imaging device filter further includes an infrared cut filter located on the light incident side with respect to the first photoelectric conversion element.

It is preferable that the above-mentioned filter for a solid-state image sensor has a through hole at a position corresponding to the infrared pass filter of the infrared cut filter.

A solid-state image sensor according to the present invention includes a light conversion element, and either the above-mentioned infrared pass filter or the above-mentioned solid-state image sensor filter.

According to the present invention, it is possible to provide a coloring composition composed of a single coloring material and having excellent stability over time, an infrared pass filter, a filter for a solid-state image sensor, and a solid-state image sensor using the same.

FIG. 1 is an exploded perspective view showing a layer structure in an embodiment of a solid-state image sensor.

The coloring composition of the present invention contains a diketopyrrolopyrrole compound represented by the following formula (1) as a coloring material.

However, in formula (1), R1, R2, R7, and R8 are a hydrogen atom, a linear alkyl group having 1 or more carbon atoms, or a branched alkyl group having 3 or more carbon atoms. Further, R3, R4, R5, and R6 are thiophene, furan, or pyrrole, and as represented by the following formula (2), the 3rd and 4th positions are unsubstituted, and the 2nd and 5th positions are unsubstituted. are combined.

When R3, R4, R5, and R6 are composed of thiophene, furan, and pyrrole, the conjugated system of the diketopyrrolopyrrole compound is expanded, and it becomes possible to absorb light in a wide range of wavelengths from the visible region to the near-infrared region. R3, R4 and R5, R6 may be all the same or different.

Preferably, R3, R4 and R5, R6 are thiophene or pyrrole. By being composed of thiophene or pyrrole, diketopyrrolopyrrole compounds exhibit high stability. More preferably, R3, R4 and R5, R6 are thiophene. By being composed of thiophene, diketopyrrolopyrrole compounds exhibit higher stability.

A hydrogen bond can be formed between the oxygen of the amide group bonded to R7 and R8, the hydrogen of R7 and R8, and the hydrogen of the linear alkyl group or the branched alkyl group. The hydrogen bonds formed allow the diketopyrrolopyrrole compounds to associate with each other to form an association that allows absorption of long wavelength light.

From the viewpoint of compound solubility, R1, R2, R7, and R8 are preferably linear alkyl groups having 12 or more carbon atoms or branched alkyl groups having 12 or more carbon atoms. R1, R2 and R7, R8 may be the same linear alkyl group or branched alkyl group, or may be different linear alkyl groups or branched alkyl groups.

The coloring composition of the present invention can contain, in addition to the diketopyrrolopyrrole compound of formula (1), a polymerizable compound, a binder resin, and a photopolymerization initiator in order to pattern a coating film by photolithography.

Examples of the polymerizable compound include pentaerythritol triacrylate, pentaerythritol tetraacrylate, trimethylolpropane triacrylate, trimethylolpropane PO-modified (n=1) triacrylate, trimethylolpropane PO-modified (n=2) triacrylate, Trimethylolpropane EO modified (n=1) triacrylate, trimethylolpropane EO modified (n=2) triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, isocyanuric Acid EO modified diacrylates, isocyanuric acid EO modified triacrylates, isocyanuric acid EO modified citriacrylates, or mixtures containing one or more thereof can be used.

Typically, the polymerizable compound used is one containing a trifunctional acrylic monomer as a main component. When an acrylic monomer used in general photosensitive resins such as a tetrafunctional monomer or a pentafunctional monomer is used as a monomer, the sensitivity of the photosensitive resin may become excessively high. As a result, the shape of the base tends to have a large influence on the shape of the colored layer. When a monomer containing a trifunctional acrylic monomer as a main component is used, it is possible to prevent the sensitivity of the photosensitive resin from becoming excessively high.

Binder resins are obtained by copolymerizing several types of monomers and oligomers. Monomers and oligomers that form the binder resin include methyl (meth)acrylate, ethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, cyclohexyl (meth)acrylate, and β-carboxylate. Ethyl (meth)acrylate, diethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, triethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate acrylate, pentaerythritol tri(meth)acrylate, glycidyl(meth)acrylate, 1,6-hexanediol diglycidyl ether di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, neopentyl glycol diglycidyl ether di( Various acrylic esters such as meth)acrylate, dipentaerythritol hexa(meth)acrylate, tricyclodecanyl(meth)acrylate, ester acrylate, (meth)acrylic ester of methylolated melamine, epoxy(meth)acrylate, and urethane acrylate. and methacrylic esters, (meth)acrylic acid, styrene, vinyl acetate, hydroxyethyl vinyl ether, ethylene glycol divinyl ether, pentaerythritol trivinyl ether, (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, N-vinylformamide, acrylonitrile Examples include. These can be used alone or in combination of two or more.

The binder resin is preferably a copolymer of a monomer having an acidic group so as to be dissolved in an alkaline developer. Carboxyl groups are mainly used as acidic groups, and examples of carboxyl group-containing monomers include unsaturated polycarboxylic acids such as unsaturated monocarboxylic acids, unsaturated dicarboxylic acids, and unsaturated tricarboxylic acids. Mention may be made of unsaturated carboxylic acids having at least one carboxyl group. Here, examples of the unsaturated monocarboxylic acid include acrylic acid, methacrylic acid, crotonic acid, α-chloroacrylic acid, and cinnamic acid. Examples of unsaturated dicarboxylic acids include maleic acid, fumaric acid, itaconic acid, citraconic acid, and mesaconic acid. The unsaturated polyhydric carboxylic acid may be an acid anhydride thereof, specifically maleic anhydride, itaconic anhydride, citraconic anhydride, or the like. Further, the unsaturated polycarboxylic acid may be a mono(2-methacryloyloxyalkyl) ester thereof, such as mono(2-methacryloyloxyethyl) succinate, mono(2-methacryloyloxyethyl) succinate, ethyl), mono(2-acryloyloxyethyl) phthalate, mono(2-methacryloyloxyethyl) phthalate, and the like. The unsaturated polycarboxylic acid may be a mono(meth)acrylate of a dicarboxy polymer at both ends thereof, such as ω-carboxypolycaprolactone monoacrylate, ω-carboxypolycaprolactone monomethacrylate, and the like. These carboxyl group-containing monomers can be used alone or in combination of two or more.

It is preferable that the weight average molecular weight of the binder resin is within the range of 5,000 to 20,000. If the weight average molecular weight is less than 5,000, only low molecular weight compounds will be present in the coloring composition, and when patterning a coating film by photolithography, the degree of curing of exposed areas will be small and a good pattern shape will not be obtained. do not have. If the weight average molecular weight exceeds 20,000, the solubility in a developer will be poor and a good pattern will not be obtained.

A thermosetting resin can be used as the binder resin, and examples of the thermosetting resin include epoxy resin, benzoguanamine resin, rosin-modified maleic acid resin, rosin-modified fumaric acid resin, melamine resin, urea resin, phenolic resin, Alternatively, a mixture containing one or more of them can be used.

Examples of photopolymerization initiators include oxime ester initiators and α-aminoalkylphenone initiators. Examples of oxime ester initiators include 1,2-octanedione, 1-[4-(phenylthio)phenyl-2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2- As the initiator, 2-benzyl-2-dimethylamino-1-(4-morpholino), methylbenzoyl)-9H-carbazol-3-yl]-,1-(O-acetyloxime), phenyl)-butanone-1,2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one.

Further, other photopolymerization initiators can also be used. Examples of photopolymerization initiators that can be used together include 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, diethoxyacetophenone, and 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane. 1-one, 1-hydroxycyclohexyl phenyl ketone, and acetophenone photopolymerization such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, benzoin, benzoin methyl ether, Benzoin-based photoinitiators such as benzoin ethyl ether, benzoin isopropyl ether, and benzyl dimethyl ketal, benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone, and 4-benzoyl Benzophenone-based photoinitiators such as -4'-methyldiphenyl sulfide, thioxanthone-based light such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, isopropylthioxanthone, and 2,4-diisopropylthioxanthone Polymerization initiator, 2,4,6-trichloro-s-triazine, 2-phenyl4,6-bis(trichloromethyl)-s-triazine, 2-(p-methoxyphenyl-4,6-bis(trichloromethyl)) -s-triazine, 2-(p-tolyl)-4,6-bis(trichloromethyl)-s-triazine, 2-piperonyl-4,6-bis(trichloromethyl)-s-triazine, 2,4-bis (Trichloromethyl)-6-styryl-chloromethyl)-s-triazine, 2,4-bis(trichloromethyl)-6-styryl-s-triazine, 2-(naphth-1-yl)-4,6-bis (trichloromethyl)-s-triazine, 2-(4-methoxynaphth-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2,4-trichloromethyl(piperonyl)-6-triazine, and Triazine photopolymerization initiators such as 2,4-trichloromethyl(4'-methoxystyryl)-6-triazine, borate photopolymerization initiators, carbazole photopolymerization initiators, imidazole photopolymerization initiators, or the like. Mixtures containing one or more of the following can be used.

Examples of the solvent include cyclohexane, cyclohexanone, ethyl cellosolve acetate, tetrahydrofuran, butyl cellosolve acetate, 1-methoxy-2-propyl acetate, diethylene glycol dimethyl ether, propylene glycol monomethyl ether acetate, ethylbenzene, ethylene glycol diethyl ether, xylene, ethyl cellosolve, methyl -n amyl ketone, propylene glycol monomethyl ether toluene, methyl ethyl ketone, ethyl acetate, methanol, ethanol, isopropyl alcohol, butanol, isobutyl ketone, petroleum solvents, or mixtures containing one or more thereof can be used.

Additionally, additives may be added to the coloring composition as necessary. As additives it is possible to use, for example, surfactants, storage stabilizers or mixtures containing one or more of these.

Examples of surfactants include sodium lauryl sulfate, polyoxyethylene alkyl ether sulfate, sodium dodecylbenzenesulfonate, alkali salts of styrene-acrylic acid copolymers, sodium stearate, sodium alkylnaphthalene sulfonate, and alkyldiphenyl ether disulfone. Sodium lauryl sulfate, monoethanolamine lauryl sulfate, triethanolamine lauryl sulfate, ammonium lauryl sulfate, monoethanolamine stearate, sodium stearate, sodium lauryl sulfate, monoethanolamine of styrene-acrylic acid copolymer, and polyoxyethylene alkyl Anionic surfactants such as ether phosphates, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene alkyl ether phosphates, polyoxyethylene sorbitan monostearate, and Nonionic surfactants such as polyethylene glycol monolaurate, cationic surfactants such as alkyl quaternary ammonium salts and their ethylene oxide adducts, alkyl betaines such as alkyldimethylaminoacetic acid betaines, and alkylimidazolines. Amphoteric surfactants, silicone surfactants, or mixtures containing one or more thereof can be used.

Storage stabilizers include, for example, quaternary ammonium chlorides such as benzyl trimethyl chloride and diethyl hydroxyamine, organic acids such as lactic acid and oxalic acid, their methyl ethers, organic acids such as t-butylpyrocatechol, triethylphosphine and triphenylphosphine, etc. Phosphine, phosphites, or mixtures containing one or more thereof can be used.

In order to pattern the coating film by photolithography, it is preferable to use a device such as a stepper exposure device and a photomask having a predetermined pattern. After exposure through a photomask, a pattern is formed by removing unexposed areas with a developer.

It is preferable to use an alkaline developer as the developer. As the alkaline developer, an inorganic alkaline developer such as sodium hydroxide, potassium hydroxide, or sodium carbonate, or an organic alkaline developer such as tetrahydroxyammonium can be used. Further, in order to improve the wettability to the coating film, it is also preferable to include a surfactant in the developer.

The coloring composition of the present invention can be used in an infrared pass filter. By using the coloring composition of the present invention, an infrared pass filter that blocks light with a wavelength of 400 to 800 nm, which is a part of the visible region and near-infrared region, and transmits light in the near-infrared region of 900 to 1000 nm, is formed. can.

The film thickness of the infrared pass filter of the present invention is usually 0.1 μm to 15 μm, preferably 0.3 to 10 μm, and more preferably 0.5 μm to 5 μm.

The colorant concentration in the film is preferably 30 to 60%. When the coloring material concentration is less than 30%, the transmittance in the visible light region increases and noise increases. Furthermore, when the coloring material concentration exceeds 60%, the transmittance of infrared rays decreases and the sensitivity decreases. Moreover, when the coloring material concentration exceeds 60%, the proportions of the polymerizable compound, binder resin, and photopolymerization initiator in the coloring composition decrease, resulting in a decrease in patterning properties in photolithography.

When the coloring material concentration in the film is 30 to 60%, the average transmittance of light in the wavelength range of 400 to 800 nm, which is part of the visible region and near-infrared region, is 30% or less when the film is formed to a thickness of 1.2 μm. Therefore, it is possible to form an infrared pass filter having an average transmittance of 90% or more for light in the near-infrared region of 900 to 1000 nm.

The coloring composition and infrared pass filter of the present invention can be used as a color filter for solid-state image sensors.

With reference to FIG. 1, a filter for a solid-state image sensor and an embodiment of the solid-state image sensor will be described. FIG. 1 is a schematic configuration diagram separately showing each layer in a part of a solid-state image sensor.

<Solid-state image sensor>
As shown in FIG. 1, the solid-state image sensor 10 includes a solid-state image sensor filter 10F and a plurality of photoelectric conversion elements 11. The solid-state image sensor filter 10F includes a plurality of visible light filters 12R, 12G, 12B, an infrared pass filter 12P, an infrared cut filter 13, a barrier layer 14, a plurality of visible light microlenses 15R, 15G, 15B, and , and an infrared microlens 15P.

The plurality of photoelectric conversion elements 11 include a red photoelectric conversion element 11R, a green photoelectric conversion element 11G, a blue photoelectric conversion element 11B, and an infrared photoelectric conversion element 11P. The solid-state image sensor 10 includes a plurality of red photoelectric conversion elements 11R, a plurality of green photoelectric conversion elements 11G, a plurality of blue photoelectric conversion elements 11B, and a plurality of infrared photoelectric conversion elements 11P. The plurality of infrared photoelectric conversion elements 11P measure the intensity of infrared rays. Note that in FIG. 1, for convenience of illustration, a repeating unit of the photoelectric conversion element 11 in the solid-state image sensor 10 is shown.

<Color filter>
The color filter for visible light includes a red filter 12R, a green filter 12G, and a blue filter 12B. The red filter 12R is located on the light incident side with respect to the red photoelectric conversion element 11R. The green filter 12G is located on the light incident side with respect to the green photoelectric conversion element 11G. The blue filter 12B is located on the light incident side with respect to the blue photoelectric conversion element 11B.

The filters 12R, 12G, and 12B for each color are formed by forming a coating film containing a colored photosensitive resin and patterning the coating film using a photolithography method. For example, a coating film containing a red photosensitive resin is formed by applying a coating liquid containing a red photosensitive resin and drying the coating film. The red filter 12R is formed by exposing a coating film containing a red photosensitive resin to a region corresponding to the red filter 12R and developing it. Note that the green filter 12G and the blue filter 12B are also formed by the same method as the red filter 12R.

As the pigment contained in the coloring composition of the red filter 12R, the green filter 12G, and the blue filter 12B, organic or inorganic pigments can be used alone or in combination of two or more types. The pigment is preferably a pigment with high color development and high heat resistance, particularly a pigment with high heat decomposition resistance, and organic pigments are usually used. Pigments that can be used include phthalocyanine, azo, anthraquinone, quinacridone, dioxazine, anthanthrone, indanthrone, perylene, thioindigo, isoindoline, quinophthalone, and diketopyrrolopyrrole. Examples include organic pigments such as pigments.
Specific examples of organic pigments that can be used in the coloring composition of the present invention are shown below using color index numbers.

Examples of blue pigments used in the blue coloring composition of filters for each color include C.I. Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 22, 60, 64. , 81, among which C.I. Pigment Blue 15:6 is preferred.

Examples of red pigments used in the red coloring composition include C.I. Pigment Red 7, 9, 14, 41, 48:1, 48:2, 48:3, 48:4, 81:1, 81:2, 81:3, 97, 122, 123, 146, 149, 168, 177, 178, 180, 184, 185, 187, 192, 200, 202, 208, 210, 215, 216, 217, 220, 223, 224, Red pigments such as 226, 227, 228, 240, 246, 254, 255, 264, 272, C.I. Pigment Orange 36, 43, 51, 55, 59, 61, 71, 73, and for toning if necessary, C.I. Pigment Yellow 1, 2, 3, 4, 5, 6, 10, 12, 13, 14, 15, 16, 17, 18, 24, 31, 32, 34, 35, 35:1, 36, 36:1 , 37, 37:1, 40, 42, 43, 53, 55, 60, 61, 62, 63, 65, 73, 74, 77, 81, 83, 93, 94, 95, 97, 98, 100, 101 , 104, 106, 108, 109, 110, 113, 114, 115, 116, 117, 118, 119, 120, 123, 126, 127, 128, 129, 138, 139, 147, 150, 151, 152, 153 , 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 179, 180, 181, 182, 185, 187, 188 , 193, 194, 198, 199, 213, 214, etc.

In addition, the green coloring composition includes, for example, green pigments such as C.I. Pigment Green 7, 10, 36, 37, 58, and 59, and C.I. Pigment Yellow 1, 2, 3, 4, and C.I. 5, 6, 10, 12, 13, 14, 15, 16, 17, 18, 24, 31, 32, 34, 35, 35:1, 36, 36:1, 37, 37:1, 40, 42, 43, 53, 55, 60, 61, 62, 63, 65, 73, 74, 77, 81, 83, 93, 94, 95, 97, 98, 100, 101, 104, 106, 108, 109, 110, 113, 114, 115, 116, 117, 118, 119, 120, 123, 126, 127, 128, 129, 138, 139, 147, 150, 151, 152, 153, 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 179, 180, 181, 182, 185, 187, 188, 193, 194, 198, 199, 213, 214 and the like.

<Infrared pass filter>
The solid-state image sensor filter 10F includes an infrared pass filter 12P on the light incident side with respect to the infrared photoelectric conversion element 11P. The infrared pass filter 12P cuts visible light that can be detected by the infrared photoelectric conversion element 11P. Thereby, the detection accuracy of infrared rays by the infrared photoelectric conversion element 11P is improved. The infrared rays that can be detected by the infrared photoelectric conversion element 11P are near infrared rays having a wavelength of 900 nm or more and 1000 nm or less.

The infrared pass filter 12P is an optical filter that blocks light in the visible region and transmits light in the near-infrared region, and includes a coloring composition, a polymerizable compound, a binder resin, and a photopolymerization initiator.

Note that the above embodiment can be modified and implemented as follows.
<Infrared cut filter>
The solid-state image sensor can also be provided with an infrared cut filter 13 separately. The infrared cut filter 13 cuts, from the photoelectric conversion elements 11, infrared rays in a wavelength band that can be detected as noise by each photoelectric conversion element 11. This improves the detection accuracy of the photoelectric conversion element 11.

For example, as shown in FIG. 1, the infrared cut filter 13 may be configured to include a through hole 13H on the light incident side of the infrared pass filter 12P and not be located on the light incident side of the infrared pass filter 12P. The infrared cut filter 13 is a layer common to the red filter 12R, the green filter 12G, and the blue filter 12B.

Further, the infrared cut filter 13 may be provided so as to be located on the light incident side with respect to the infrared pass filter 12P. That is, the infrared cut filter 13 does not need to be provided with the through hole 13H. In this case, the infrared cut filter 13 is configured to block near infrared rays having a wavelength of 700 nm or more and less than 900 nm, for example. With this configuration, the infrared photoelectric conversion element 11P can also efficiently detect near-infrared rays having a wavelength of 900 nm or more and 1000 nm or less.

The constituent material of the infrared cut filter 13 is a transparent resin containing an infrared absorbing dye. Examples of infrared absorbing dyes include anthraquinone dyes, cyanine dyes, phthalocyanine dyes, dithiol dyes, diimonium dyes, squarylium dyes, and croconium dyes. Examples of the transparent resin include acrylic resin, polyamide resin, polyimide resin, polyurethane resin, polyester resin, polyether resin, polyolefin resin, polycarbonate resin, polystyrene resin, and norbornene resin. The infrared cut filter 13 is formed by film formation using a liquid phase film formation method such as a coating method.

The infrared pass filter 12P may be thicker than the color filters 12R, 12G, and 12B. With this configuration, it is possible to improve the non-transmission of visible light in the infrared pass filter 12P.

Note that the accuracy of the processing of the microlenses 15R, 15G, 15B, and 15P may be reduced due to differences in level in the base on which they are formed. In the configuration including the infrared cut filter 13, from the viewpoint of improving the flatness of the base of each microlens 15R, 15G, 15B, 15P, the thickness of each color filter 12R, 12G, 12B and the thickness of the infrared cut filter 13 are It is preferable that the total thickness of the infrared pass filter 12P is approximately equal to the thickness of the infrared pass filter 12P.

Examples of the present invention are shown below, but the technical scope of the present invention is not limited to these examples.

<Synthesis of diketopyrrolopyrrole compound 1>
Prepare 100 parts by mass of tert-amyl alcohol and 71.5 parts by mass of sodium tert-pentoxide, put them into a reaction vessel equipped with a stirring device and a reflux tube, and introduce nitrogen gas into the reaction vessel. , stirred and refluxed for 1 hour while heating to 100°C. A solution prepared by dissolving 30 parts by mass of 2-thiophenecarbonitrile and 30 parts by mass of diethyl succinate in 25 parts by mass of tert-amyl alcohol was added to the stirred solution, and then heated to 100°C for 10 hours. Stir and reflux. After the stirred solution was cooled to room temperature, 50 parts by mass of methanol was added to precipitate a solid. Precursor 1 was obtained by filtering the stirred solution heated to 70°C.

Prepare 3 parts by mass of Precursor 1, 1.8 parts by mass of potassium carbonate, and 100 parts by mass of N,N-dimethylformamide, put them into a reaction vessel equipped with a stirring device and a reflux tube, and place them into a reaction vessel equipped with a stirring device and a reflux tube. The mixture was stirred and refluxed for 1 hour while heating to 120° C. while introducing nitrogen gas into the mixture. While adding 6 parts by mass of 1-bromodecane to the stirred solution, the mixture was further stirred and refluxed for 20 hours. Precursor 2 was obtained by concentrating the stirred solution and washing the concentrate with hexane.

Prepare 2 parts by mass of Precursor 2, 100 parts by mass of chloroform, and 1.3 parts by mass of N-bromosuccinimide, put these into a reaction vessel equipped with a stirring device, and introduce nitrogen gas into the reaction vessel. The mixture was stirred for 1 hour while being introduced. Precursor 3 was obtained by adding 50 parts by mass of methanol to the stirred solution and filtering the generated precipitate.

Prepare 5.5 parts by mass of precursor 3, 0.2 parts by mass of tetrakistriphenylphosphine palladium (0), 25 parts by mass of sodium carbonate, 100 parts by mass of tetrahydrofuran, and 50 parts by mass of distilled water. These were placed in a reaction vessel equipped with a stirring device and a reflux tube, and while nitrogen gas was introduced into the reaction vessel, the mixture was stirred and refluxed for 30 minutes while heating to 50°C. A solution prepared by dissolving 3 parts by mass of 5-formyl-2-thiopheneboronic acid in 50 parts by mass of tetrahydrofuran was added to the stirred solution, and the mixture was stirred and refluxed for 10 hours while heating to 70°C. After extracting and concentrating the aqueous layer of the stirred solution, it was purified by silica gel column chromatography to obtain Precursor 4.

2.5 parts by mass of precursor 4, 4 parts by mass of N-dodecylcyanoacetamide, 100 parts by mass of tetrahydrofuran, and 2.5 parts by mass of piperidine were prepared, and a stirring device and a reflux pipe were installed. The mixture was stirred and refluxed for 24 hours while heating to 70°C while introducing nitrogen gas into the reaction vessel. After concentrating the stirred solution, it was purified by silica gel column chromatography to obtain diketopyrrolopyrrole compound 1.

<Synthesis of binder resin 1>
Prepare 60 parts by weight of propylene glycol monomethyl ether acetate, 40 parts by weight of phenyl methacrylate, and 0.60 parts by weight of benzoyl peroxide, and put these into a reaction vessel equipped with a stirring device and a reflux tube to react. While introducing nitrogen gas into the container, the mixture was stirred and refluxed for 8 hours while heating to 80°C. As a result, binder resin 1 was obtained.

<Preparation of coloring composition>
Liquid preparation example 1
4.5 parts by mass of diketopyrrolopyrrole compound 1 as a coloring material, 4.3 parts by mass of M-350 (manufactured by Toagosei Co., Ltd.) as a polymerizable compound, and 5.4 parts by mass of binder resin 1 as a binder resin. 0.9 parts by mass of OXE02 (manufactured by BASF) as a photopolymerization initiator, 60 parts by mass of propylene glycol monomethyl ether acetate as a solvent, and 25 parts by mass of tetrahydrofuran were prepared, and these were stirred for 2 hours. Evaluation liquid 1 was obtained.

Preparation examples 2 to 7
Evaluation liquids 2 to 7 were obtained in the same manner as in Preparation Example 1, except that the amounts of each component were changed as shown in Table 1.

Preparation example 8
Evaluation liquid 8 was obtained in the same manner as in Preparation Example 1, except that Precursor 2 was used as the coloring material.

Preparation example 9
Evaluation liquid 9 was obtained in the same manner as in Preparation Example 1, except that diketopyrrolopyrrole compound 2, which is obtained as an impurity when purifying Precursor 4 as a coloring material, was used in Preparation Example 1.

<Temporal stability evaluation>
The initial viscosity of the evaluation liquid immediately after preparation was measured using a TVE-22LT model viscometer (manufactured by Toki Sangyo Co., Ltd.) while maintaining the temperature of the evaluation liquid at 25°C. Next, the evaluation liquid was held at 25°C for 168 hours, and then the viscosity over time was measured while keeping the temperature of the evaluation liquid at 25°C, and the rate of change in viscosity over time was calculated using the following formula to evaluate the stability over time.
Viscosity change rate (%) = (｜Initial viscosity -Viscosity over time after 168 hours of holding at -25°C｜
/ initial viscosity) x 100

A viscosity change rate of 10% or less is a standard for stability, and evaluation liquids 1 to 9 showed high stability over time with a viscosity change rate of 5% or less.

<Example 1>
Evaluation liquid 1 was applied onto a glass substrate using a spin coater so that the film thickness after baking was 1.2 μm, and baking treatment was performed on a hot plate at 100° C. for 2 minutes to obtain the filter of Example 1. .

<Examples 2 to 4>
Filters of Examples 2 to 4 were obtained in the same manner as in Preparation Example 1 using Evaluation Solutions 2 to 4.

<Comparative Examples 1 to 5>
Filters of Comparative Examples 1 to 5 were obtained in the same manner as in Example 1 using Evaluation Solutions 5 to 9.

<Spectral characteristic evaluation>
For each of the obtained filters, the transmittance of light with a wavelength of 400 to 1100 nm was measured using a spectrophotometer U-4100 (manufactured by Hitachi High-Technologies). Table 2 shows the average transmittance of light with a wavelength of 400 to 800 nm and the average transmittance of light with a wavelength of 900 to 1000 nm.

The filter using the coloring composition implemented in the present invention has an average transmittance of 30% or less for light in the wavelength range of 400 to 800 nm, which is a part of the visible region and the near-infrared region, and has a transmittance of 900 to 800 nm in the near-infrared region. The average transmittance of light at 1000 nm was 90% or more, showing good characteristics as an infrared pass filter.

INDUSTRIAL APPLICATION This invention can be utilized for a solid-state imaging device etc.

10...Solid-state imaging device 10F...Filter for solid-state imaging device 11...Photoelectric conversion element 11R...Photoelectric conversion element for red 11G...Photoelectric conversion element for green 11B...Photoelectric conversion element for blue 11P...Photoelectric conversion element for infrared 12R...Filter for red 12G...Green filter 12B...Blue filter 12P...Infrared pass filter 13...Infrared cut filter 13H...Through hole 14...Barrier layer 15R...Red microlens 15G...Green microlens 15B...Blue microlens 15P...Infrared rays Microlens 15S...Incidence surface

Claims (8)

A coloring composition containing a diketopyrrolopyrrole compound represented by the following formula (1) as a coloring material

However, in formula (1), R1, R2, R7, and R8 are a hydrogen atom, a linear alkyl group having 1 or more carbon atoms, or a branched alkyl group having 3 or more carbon atoms. In addition, R3, R4, R5, and R6 are furan or pyrrole, and as represented by the following formula (2), the 3rd and 4th positions are unsubstituted and are bonded to the 2nd and 5th positions. are doing.
The coloring composition according to claim 1, comprising a polymerizable compound, a binder resin, and a photoinitiator. An infrared pass filter comprising the coloring composition according to claim 1 or 2. The coloring material concentration in the film is 30 to 60%, and when the film is formed to a thickness of 1.2 μm, the average transmittance of light in the wavelength range of 400 to 800 nm, which is part of the visible region and near-infrared region, is 30% or less. 4. The infrared pass filter according to claim 3, wherein the infrared pass filter has an average transmittance of 90% or more for light in the near-infrared region of 900 to 1000 nm. Three color filters, a red filter, a green filter, and a blue filter, located on the light incident side with respect to the first photoelectric conversion element;
A filter for a solid-state imaging device, comprising the infrared pass filter according to claim 3 or 4, which is located on the light incident side with respect to the second photoelectric conversion element. The filter for a solid-state image sensor according to claim 5, further comprising an infrared cut filter located on a light incident side with respect to the first photoelectric conversion element. The filter for a solid-state imaging device according to claim 6, wherein the infrared cut filter has a through hole at a position corresponding to the infrared pass filter. A photoelectric conversion element,
A solid-state image sensor comprising either the infrared pass filter according to claim 3 or 4 and the solid-state image sensor filter according to any one of claims 5 to 7.