JP7500950B2 - Infrared pass filter, filter for solid-state image sensor, and solid-state image sensor - Google Patents

Description

The present invention relates to an infrared pass filter, a filter for a solid-state imaging device that includes the same, and a solid-state imaging device that includes the same.

Solid-state imaging devices such as CMOS image sensors and CCD image sensors have photoelectric conversion elements that convert the intensity of light into an electrical signal. Above the photoelectric conversion elements, color filters for each color are provided to correspond to each pixel, and above the color filters, microlenses are provided to correspond to each pixel, so that the light collected by the microlenses is colored by the color filters and enters the photoelectric conversion elements.

A solid-state imaging element that captures not only visible light images but also infrared light images has color filters for each color on multiple photoelectric conversion elements, and an infrared pass filter on the infrared photoelectric conversion element (see, for example, Patent Document 1).

The infrared pass filter blocks visible light that can be detected by the infrared photoelectric conversion element, thereby improving the detection accuracy of the infrared light 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 Documents 2 and 3).

The possible range of applications of solid-state imaging elements that enable the detection of infrared light is not limited to the range of applications of solid-state imaging elements that detect visible light, but extends to a variety of other uses. Therefore, technology that increases the durability of infrared pass filters, and ultimately the durability of solid-state imaging elements, could significantly promote the widespread use of solid-state imaging elements for monitoring and analysis under a variety of conditions.

JP 2008-91535 A JP 2016-177273 A JP 2018-119077 A

On the other hand, the materials that make up infrared pass filters are not as durable as those that make up photoelectric conversion elements, such as in terms of heat resistance and light resistance. In addition, the infrared pass filters described in the above-mentioned prior art contain several colorants in order to sufficiently block visible light. If even one of the colorants contained in the filter has low durability, the infrared pass filter will have low durability. In order to significantly promote the use of solid-state imaging elements for monitoring and analysis under various conditions, it is necessary to improve the infrared light detection accuracy of infrared pass filters, and ultimately the spectral detection accuracy of visible light and infrared light of solid-state imaging elements.

The object of the present invention is to provide an infrared pass filter that improves the durability of a solid-state imaging element that captures not only visible light images but also infrared light images, a filter for a solid-state imaging element that includes the infrared pass filter, and a solid-state imaging element that includes the filter for a solid-state imaging element.

The infrared pass filter of the present invention, which is intended to solve the above problems, is an optical filter that blocks light in the visible region and transmits light in the near-infrared region, and contains 40 to 70% by weight of a perylene pigment with an average particle size of 50 to 300 nm.

The infrared pass filter preferably has an average transmittance of 30% or less for light with wavelengths of 400 to 800 nm, which is part of the visible region and near-infrared region, and an average transmittance of 70% or more for light with wavelengths of 900 to 1000 nm in the near-infrared region.

The infrared pass filter preferably contains an acrylic polymer. By containing an acrylic polymer, it is possible to increase the possibility of providing an infrared pass filter with high durability.

The solid-state imaging device filter of the present invention, which solves the above problem, includes color filters for multiple colors and the above-mentioned infrared pass filter of the present invention, positioned on the light incident side of the photoelectric conversion element.

It is preferable that the solid-state imaging device filter includes an infrared cut filter located on the light incidence side further than the color filters for each of the plurality of colors and the infrared pass filter.

The infrared cut filter has a through hole at a position overlapping the infrared pass filter in a plan view.

The solid-state imaging device filter preferably includes a barrier layer for suppressing the transmission of an oxidation source that oxidizes the infrared pass filter at a position on the light incident side further than the color filters for each of the plurality of colors and the infrared pass filter, and the oxygen permeability of the barrier layer is preferably 5.0 cc/ ^m2 /day/atom or less. By including such a barrier layer, it is possible to increase the possibility of providing a solid-state imaging device filter with high durability.

To solve the above problem, the solid-state imaging device of the present invention includes a plurality of photoelectric conversion elements and the above-described filter for the solid-state imaging device of the present invention.

The present invention provides an infrared pass filter that improves the durability of a solid-state imaging device, a filter for a solid-state imaging device that includes the infrared pass filter, and a solid-state imaging device that includes the filter for a solid-state imaging device.

1 is a schematic perspective view illustrating one embodiment of a solid-state imaging device of the present invention, in which one unit in an XY plane is disassembled into components in the Z direction.

With reference to Figure 1, an embodiment of the infrared cut filter, filter for solid-state imaging device, and solid-state imaging device of the present invention will be described. Figure 1 is a schematic perspective view illustrating an example of one unit in the X-Y plane of a solid-state imaging device that is actually stacked and integrated, broken down into each component in the Z direction. Note that in this embodiment, infrared light means light having a wavelength in the range of 800 nm or more and 1 mm or less, and near-infrared light means infrared light having a wavelength in the range of 800 nm or more and 1100 nm or less.

[Solid-state imaging element]
1, a solid-state imaging device (one unit) 10 is composed of a solid-state imaging device filter 10F and a plurality of photoelectric conversion elements 11. The plurality of photoelectric conversion elements 11 are composed of a red photoelectric conversion element 11R, a green photoelectric conversion element 11G, a blue photoelectric conversion element 11B, and an infrared light photoelectric conversion element 11P. The infrared light photoelectric conversion element 11P converts the intensity of infrared light into an electrical signal.

<Filters for solid-state imaging devices>
The filter for solid-state imaging devices of the present invention includes a plurality of color filters 12R, 12G, and 12B for visible light, an infrared pass filter 12P of the present invention, a plurality of microlenses 15R, 15G, and 15B for visible light, and a microlens 15P for infrared light. It is also preferable to include an infrared cut filter 13, and it is more preferable to include a barrier layer 14. The filter for solid-state imaging devices 10F of FIG. 1 shows a form including all of these components.
Hereinafter, each element constituting the solid-state imaging device filter 10F will be described.

(Color filter)
The color filters for visible light are composed of a red filter 12R, a green filter 12G, and a blue filter 12B. The red filter 12R is located on the light incident side of the red photoelectric conversion element 11R, the green filter 12G is located on the light incident side of the green photoelectric conversion element 11G, and the blue filter 12B is located on the light incident side of the blue photoelectric conversion element 11B, so as to overlap each other in a plan view.

Each color filter 12R, 12G, 12B is formed by forming a coating film containing a colored photosensitive resin and patterning the coating film using a photolithography method. First, 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. Next, the red filter 12R is formed by exposing the coating film to an area corresponding to the red filter 12R and developing it. The green filter 12G and the blue filter 12B are also formed in sequence 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, an organic or inorganic pigment can be used alone or in a mixture of two or more kinds. The pigment is preferably a pigment having high color development and high heat resistance, particularly a pigment having high thermal decomposition resistance, and an organic pigment is usually used. Examples of the pigment that can be used include organic pigments such as phthalocyanine-based, azo-based, anthraquinone-based, quinacridone-based, dioxazine-based, anthanthrone-based, indanthrone-based, perylene-based, thioindigo-based, isoindoline-based, quinophthalone-based, and diketopyrrolopyrrole-based pigments.
Specific examples of organic pigments that can be used in the coloring composition are shown below by color index numbers.

Blue pigments used in the blue coloring composition of the blue filter include, for example, pigments such as C.I. Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 22, 60, 64, and 81, with C.I. Pigment Blue 15:6 being preferred. Purple pigments for toning include, for example, pigments such as C.I. Pigment Violet 1, 19, 23, 27, 29, 30, 32, 37, 40, 42, and 50, with C.I. Pigment Violet 23 being preferred.

Red coloring compositions include, for example, 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, 226, 227, 228, 240, 246, 254, 255, 264, 272, C.I. This composition is obtained by using red pigments such as Pigment Orange 36, 43, 51, 55, 59, 61, 71, and 73, and, if necessary, a yellow pigment described below for color matching.

The green coloring composition is a composition obtained by using a green pigment such as C.I. Pigment Green 7, 10, 36, 37, 58, or 59, and, if necessary, a yellow pigment as described below for color adjustment.

Yellow pigments for color mixing include 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, 1 20, 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 other pigments are listed, and among them, C.I. Pigment Yellow 13, 150, 185 are preferred.

(Infrared pass filter)
The solid-state imaging device filter 10F includes an infrared pass filter 12P on the light incident side of the infrared light photoelectric conversion element 11P. The infrared pass filter 12P cuts visible light that can be detected by the infrared light photoelectric conversion element 11P. This improves the detection accuracy of infrared light by the infrared light photoelectric conversion element 11P. The infrared light that can be detected by the infrared light photoelectric conversion element 11P is near-infrared light having a wavelength of 800 nm or more and 1100 nm or less.

As described above, 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 its constituent materials include a black pigment and a transparent resin. The black pigment is preferably a perylene pigment that has a single black color. For example, black colorants such as azo-based and methine-based materials have low durability against heat and light, and in the case of a mixture that has a black color due to two or more colorants, if even one of the pigments contained has low durability, the infrared pass filter will have low durability. In addition, the average transmittance of light in the visible region with wavelengths of 400 to 800 nm becomes higher than 30%, and it becomes impossible to block light in the visible region, so that the infrared light photoelectric conversion element 11P detects visible light that becomes noise, resulting in a solid-state imaging element with low detection accuracy.

The average particle size of the perylene pigment contained in the infrared pass filter 12P of the present invention is 50 to 300 nm, and more preferably 50 to 100 nm. If the average particle size is smaller than 50 nm, the surface area of the pigment will be large, and the pigment itself will be prone to decomposition due to the absorption of heat and light energy, resulting in low durability. Furthermore, if the average particle size is larger than 300 nm, the surface irregularities of the infrared pass filter film will be large, and the incident light will be easily reflected and scattered by the surface irregularities, reducing the amount of infrared light that can be detected by the infrared light photoelectric conversion element 11P, resulting in a solid-state imaging element with low detection accuracy.

The average particle size of the pigment refers to the numerical value of the average particle size (D50) of the pigment particles in the pigment dispersion (mill base). Specifically, it is measured by the dynamic light scattering method, for example, the average particle size measured with Nikkiso Co., Ltd.'s "Nanotrac UPA-EX150."

The infrared pass filter 12P of the present invention contains 40 to 70% by weight of perylene pigment. If the perylene pigment content is less than 40% by weight, it will not be possible to block light in the visible range, and the infrared light photoelectric conversion element 11P will also detect visible light that becomes noise, resulting in a solid-state imaging element with low detection accuracy. Furthermore, if the perylene pigment content is more than 70% by weight, the content of other substances besides the pigment will be reduced, making it more likely that cracks and surface irregularities will occur during coating formation, making it impossible to form a uniform film.

The transmission spectrum of the infrared pass filter 12P is preferably such that the average transmittance of light with wavelengths of 400 to 800 nm is 30% or less, and more preferably 10% or less. If the average transmittance of light with wavelengths of 400 to 800 nm is higher than 30%, light in the visible region cannot be blocked, and the infrared light photoelectric conversion element 11P detects visible light that becomes noise, resulting in a solid-state imaging element with low detection accuracy. In addition, the average transmittance of light in the near-infrared region of 900 to 1000 nm is preferably 70% or more, and more preferably 80% or more. If the average transmittance of light in the near-infrared region of 900 to 1000 nm is lower than 70%, less near-infrared light passes through the infrared pass filter, resulting in a solid-state imaging element with low detection accuracy.

Near-infrared light having a wavelength of 850 nm and near-infrared light having a wavelength of 940 nm are absorbed and removed by water vapor contained in the atmosphere. The infrared photoelectric conversion element 11P detects at least one of the near-infrared light having a wavelength of 850 nm and the near-infrared light having a wavelength of 940 nm.

In particular, the sunlight spectrum has an absorption band around 940 nm caused by the absorption of water vapor, which reduces the spectral intensity. Therefore, when the solid-state imaging element is used outdoors or during the day, near-infrared light with a wavelength of 940 nm is less susceptible to the influence of sunlight, which is disturbing light. Therefore, if the central wavelength of the light source used is set to 940 nm, it is possible to provide a solid-state imaging element with less noise. Therefore, it is preferable that the infrared photoelectric conversion element 11P detects near-infrared light with a wavelength of 940 nm.

The binder resin forming the infrared pass filter 12P is preferably an acrylic polymer, which has excellent durability. The acrylic polymer is a polymer compound formed by polymerizing a monomer containing acrylic acid or methacrylic acid. The monomer containing acrylic acid is an acrylate, and the monomer containing methacrylic acid is a methacrylate. The acrylic polymer may contain a monomer other than the acrylic monomers described above.

The monomers other than the above-mentioned acrylic monomers may be, for example, styrene-based monomers, (meth)acrylic monomers, vinyl ester-based monomers, vinyl ether-based monomers, halogen-containing vinyl-based monomers, and diene-based monomers. The styrene-based monomers may be, for example, styrene, α-methylstyrene, p-methylstyrene, m-methylstyrene, p-methoxystyrene, p-hydroxystyrene, p-acetoxystyrene, vinyltoluene, ethylstyrene, phenylstyrene, and benzylstyrene.

The (meth)acrylic monomer may be, for example, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, and 2-ethylhexyl methacrylate. The vinyl ester monomer may be, for example, vinyl acetate. The vinyl ether monomer may be, for example, vinyl methyl ether. The halogen-containing vinyl monomer may be, for example, vinyl chloride. The diene monomer may be, for example, butadiene and isobutylene. The acrylic polymer may contain only one type of monomer other than the above-mentioned acrylic monomer, or may contain two or more types.

The acrylic polymer may also contain a monomer for adjusting the polarity of the acrylic polymer. The monomer for adjusting the polarity adds an acid group or a hydroxyl group to the acrylic polymer. Such a monomer may be, for example, acrylic acid, methacrylic acid, maleic anhydride, maleic acid half ester, 2-hydroxyethyl acrylate, and 4-hydroxyphenyl (meth)acrylate.

When the acrylic polymer is a copolymer in which two or more kinds of acrylic monomers are polymerized, the acrylic polymer may have any of the following structures: random copolymer, alternating copolymer, block copolymer, and graft copolymer. If the acrylic polymer has a random copolymer structure, the manufacturing process is easy. Therefore, random copolymers are more preferable than other copolymers.

The polymerization method for obtaining the acrylic polymer may be, for example, radical polymerization, cationic polymerization, anionic polymerization, living radical polymerization, living cationic polymerization, and living anionic polymerization. As the polymerization method for obtaining the acrylic polymer, radical polymerization is preferably selected because it is easy to produce industrially. The radical polymerization may be a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, and a suspension polymerization method. For the radical polymerization, it is preferable to use a solution polymerization method. By using the solution polymerization method, it is easy to control the molecular weight of the acrylic polymer. Furthermore, after polymerization of the acrylic monomer, the solution containing the acrylic polymer can be used in the form of a solution for manufacturing a filter for a solid-state imaging device.

In radical polymerization, the above-mentioned acrylic monomer may be diluted with a polymerization solvent, and then a radical polymerization initiator may be added to polymerize the acrylic monomer.

The polymerization solvent may be an ester solvent, an alcohol ether solvent, a ketone solvent, an aromatic solvent, an amide solvent, an alcohol solvent, or the like. The ester solvent may be, for example, methyl acetate, ethyl acetate, n-butyl acetate, isobutyl acetate, t-butyl acetate, methyl lactate, or ethyl lactate. The alcohol ether solvent may be, for example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, 3-methoxy-1-butanol, or 3-methoxy-3-methyl-1-butanol. The ketone solvent may be, for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, or cyclohexanone.

The aromatic solvent may be, for example, benzene, toluene, xylene, etc. The amide solvent may be, for example, formamide, dimethylformamide, etc. The alcohol solvent may be, for example, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, s-butanol, t-butanol, diacetone alcohol, 2-methyl-2-butanol, etc. Among these, ketone solvents and ester solvents are preferred because they can be used in the manufacture of filters for solid-state imaging devices. Note that, among the above-mentioned polymerization solvents, one type may be used alone, or two or more types may be mixed and used.

In radical polymerization, the amount of polymerization solvent used is not particularly limited, but when the total amount of acrylic monomers is set to 100 parts by weight, the amount of polymerization solvent used is preferably 1 part by weight or more and 1,000 parts by weight or less, and more preferably 10 parts by weight or more and 500 parts by weight or less.

The radical polymerization initiator may be, for example, a peroxide or an azo compound. The peroxide may be, for example, benzoyl peroxide, t-butyl peroxyacetate, t-butyl peroxybenzoate, and di-t-butyl peroxide. The azo compound may be, for example, azobisisobutyronitrile, azobisamidinopropane salt, azobiscyanovaleric acid (salt), and 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide].

The amount of radical polymerization initiator used is preferably 0.0001 parts by weight or more and 20 parts by weight or less, more preferably 0.001 parts by weight or more and 15 parts by weight or less, and even more preferably 0.005 parts by weight or more and 10 parts by weight or less, when the total amount of acrylic monomers is set to 100 parts by weight. The radical polymerization initiator may be added to the acrylic monomers and polymerization solvent before the start of polymerization, or may be dropped into the polymerization reaction system. Dropping the radical polymerization initiator into the polymerization reaction system for the acrylic monomers and polymerization solvent is preferable because it can suppress heat generation due to polymerization.

The constituent material of the infrared pass filter 12P can contain inorganic oxide particles to adjust the refractive index. The durability of the infrared pass filter is improved when inorganic oxide particles that are highly resistant to heat and light are contained. Examples of inorganic oxides are aluminum oxide, silicon oxide, zirconium oxide, and titanium oxide. The infrared pass filter 12P can contain additives to provide other functions, such as a light stabilizer, an antioxidant, a heat stabilizer, and an antistatic agent.

The infrared pass filter 12P can have a thickness of, for example, 300 nm or more and 3 μm or less.

The infrared pass filter 12P is formed by forming a coating film from a curable composition containing a black pigment and an acrylic polymer, and then patterning the coating film using a photolithography method or a dry etching method.

The black pigment is finely dispersed in a colorant carrier such as a resin and/or a solvent, together with a dispersing aid as necessary, using various dispersing means such as a kneader, two-roll mill, three-roll mill, ball mill, horizontal sand mill, vertical sand mill, annular bead mill, or attritor to produce a dispersion, which is then mixed with an acrylic polymer and a solvent to obtain a curable composition.

When dispersing a colorant such as a black pigment, a dispersing aid such as a resin-type dispersant or a surfactant may be added as appropriate. Dispersing aids are highly effective in preventing reagglomeration of the colorant after dispersion, so compositions dispersed using dispersing aids have good spectral characteristics and viscosity stability.

Resin-type dispersants have a colorant-affinity site that has the property of adsorbing to added pigments, and a site that is compatible with the colorant carrier, and they function by adsorbing to the added colorant and stabilizing its dispersion in the colorant carrier. Specific examples of resin-type dispersants include polyurethane, polyacrylate and other polycarboxylate esters, unsaturated polyamides, polycarboxylic acids, polycarboxylate (partial) amine salts, polycarboxylate ammonium salts, polycarboxylate alkylamine salts, polysiloxanes, long-chain polyaminoamide phosphates, hydroxyl-containing polycarboxylate esters, and their modifications; oil-based dispersants such as amides formed by the reaction of poly(lower alkylene imines) with polyesters having free carboxyl groups and their salts; water-soluble resins and water-soluble polymer compounds such as (meth)acrylic acid-styrene copolymers, (meth)acrylic acid-(meth)acrylic acid ester copolymers, styrene-maleic acid copolymers, polyvinyl alcohol, and polyvinylpyrrolidone; polyesters, modified polyacrylates, ethylene oxide/propylene oxide adducts, and phosphate esters; these can be used alone or in a mixture of two or more types, but are not necessarily limited to these.

It is preferable to use about 5 to 200% by weight of the resin-type dispersant based on the total amount of pigment, and from the viewpoint of film-forming properties, it is more preferable to use about 10 to 100% by weight.

A commercially available resin-type dispersant is Disperbyk-1 manufactured by BYK Japan.
01, 103, 107, 108, 110, 111, 116, 130, 140, 154, 161, 162, 163, 164, 165, 166, 170, 171, 174, 180, 181, 182, 183, 184, 185, 190, 2000, 2001, 2020, 2025, 2050, 2070, 2095, 2150, 2155, or Anti-Terra-U, 203, 204, or BYK- P104, P104S, 220S, 6919, or Lactimon, Lactimon-WS, or Bykumen, etc., SOLSPERSE-3000, 9000, 13000, 13240, 13650, 13940, 16000, 17000, 18000, 20000, 21000, 24000, 26000, 27000, 28000, 31845, 32000 manufactured by Lubrizol Japan Co., Ltd. 32500, 32550, 33500, 32600, 34750, 35100, 36600, 38500, 41000, 41090, 53095, 55000, 76500, etc. manufactured by Ciba Japan Co., Ltd. EFKA-46, 47, 48, 452, 4008, 4009, 4010, 4015, 4020, 4047, 4050, 4055, 4060, 4080, 4400, 4401, 4402, 4403, 4404, 4405, 4406, 4407, 4408, 4409, 4500, 4501, 4502, 4503, 4504, 4505, 4506, 4507, 4508, 4509, 4600, 4600, 4600, 4601, 4602, 4603, 4604, 4605, 4606, 4607, 4608, 4609, 4700, 4701, 4702, 4703, 4704, 4705, 4706, 4707, 4708, 4709, 4800, 4801, 4802, 4803, 4804, 4805, 4806, 4807, 4808, 4809, 4900, 4901, 490 06, 4408, 4300, 4310, 4320, 4330, 4340, 450, 451, 453, 4540, 4550, 4560, 4800, 5010, 5065, 5066, 5070, 7500, 7554, 1101, 120, 150, 1501, 1502, 1503, etc., and Ajisper PA111, PB711, PB821, PB822, PB824, etc. manufactured by Ajinomoto Fine-Techno Co., Ltd.

Examples of surfactants include anionic surfactants such as sodium lauryl sulfate, polyoxyethylene alkyl ether sulfate, sodium dodecylbenzene sulfonate, alkali salts of styrene-acrylic acid copolymers, sodium stearate, sodium alkyl naphthalene sulfonate, sodium alkyl diphenyl ether disulfonate, monoethanolamine lauryl sulfate, triethanolamine lauryl sulfate, ammonium lauryl sulfate, monoethanolamine stearate, monoethanolamine of styrene-acrylic acid copolymers, and polyoxyethylene alkyl ether phosphates; nonionic surfactants such as polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene alkyl ether phosphates, polyoxyethylene sorbitan monostearate, and polyethylene glycol monolaurate; cationic surfactants such as alkyl quaternary ammonium salts and their ethylene oxide adducts; alkyl betaines such as alkyl dimethylaminoacetate betaines, and amphoteric surfactants such as alkyl imidazolines, which may be used alone or in a mixture of two or more, but are not necessarily limited to these.

When a resin-type dispersant or surfactant is added, the amount is preferably 0.1 to 55 parts by weight, and more preferably 0.1 to 45 parts by weight, per 100 parts by weight of colorant. If the amount of resin-type dispersant or surfactant is less than 0.1 parts by weight, it is difficult to obtain the desired effect, and if the amount is more than 55 parts by weight, the excess dispersant may adversely affect the dispersion.

When photolithography is used to form the infrared pass filter 12P, the constituent material of the infrared pass filter 12P is a photosensitive composition containing a black pigment and an acrylic polymer. The photosensitive composition contains a photopolymerization initiator, a polymerizable monomer, an organic solvent, a leveling agent, etc.

As photopolymerization initiators, acetophenone-based photopolymerization initiators, benzoin photopolymerization initiators, benzophenone-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, triazine-based photopolymerization initiators, oxime ester-based photopolymerization initiators, etc. are used alone or in combination of two or more.

Polymerizable monomers include (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, cyclohexyl (meth)acrylate, phenoxyethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isobornyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, tetrahydrofuran, Examples of such monomers include (meth)acrylic acid esters such as furfuryl (meth)acrylate; N-vinylpyrrolidone; styrene and its derivatives, styrenes such as α-methylstyrene; acrylamides such as (meth)acrylamide, methylol (meth)acrylamide, alkoxymethylol (meth)acrylamide, and diacetone (meth)acrylamide; other vinyl compounds such as (meth)acrylonitrile, ethylene, propylene, butylene, vinyl chloride, and vinyl acetate; and macromonomers such as polymethyl methacrylate macromonomer and polystyrene macromonomer. These monomers can be used alone or in combination of two or more.

Examples of organic solvents include ethyl lactate, benzyl alcohol, 1,2,3-trichloropropane, 1,3-butanediol, 1,3-butylene glycol, 1,3-butylene glycol diacetate, 1,4-dioxane, 2-heptanone, 2-methyl-1,3-propanediol, 3,5,5-trimethyl-2-cyclohexen-1-one, 3,3,5-trimethylcyclohexanone, ethyl 3-ethoxypropionate, 3-methyl-1,3-butanediol, 3-methoxy-3-methyl-1-butanol, 3-methoxy-3-methylbutyl acetate, 3-methoxybutanol, 3-methoxybutyl acetate, 4-heptanone, m-xylene, m-diethylbenzene, m-dichlorobenzene, N,N-dimethylacetamide, N,N-dimethylformamide, n-butyl alcohol. butyl ether, n-propyl acetate, o-xylene, o-chlorotoluene, o-diethylbenzene, o-dichlorobenzene, p-chlorotoluene, p-diethylbenzene, sec-butylbenzene, tert-butylbenzene, γ-butyrolactone, isobutyl alcohol, isophorone, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monotertiary butyl ether, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, ethylene glycol monopropyl ether, ethylene glycol monohexyl ether, ethylene glycol ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, diisobutyl ketone, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether, cyclohexanol, cyclohexanol acetate, cyclohexanone, dipropylene glycol dimethyl ether, dipropylene glycol methyl ether acetate, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monomethyl Examples of the esters include propylene glycol ether, diacetone alcohol, triacetin, tripropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, propylene glycol diacetate, propylene glycol phenyl ether, propylene glycol monoethyl ether, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether, propylene glycol monopropyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether propionate, benzyl alcohol, methyl isobutyl ketone, methylcyclohexanol, n-amyl acetate, n-butyl acetate, isoamyl acetate, isobutyl acetate, propyl acetate, and dibasic acid esters. These can be used alone or in combination of two or more.

As the leveling agent, dimethylsiloxane having a polyether structure or polyester structure in the main chain is preferable. Specific examples of dimethylsiloxane having a polyether structure in the main chain include FZ-2122 manufactured by Dow Corning Toray Co., Ltd. and BYK-333 manufactured by BYK-Chemie. Specific examples of dimethylsiloxane having a polyester structure include BYK-310 and BYK-370 manufactured by BYK-Chemie. Dimethylsiloxane having a polyether structure and dimethylsiloxane having a polyester structure can also be used in combination. These can be used alone or in a mixture of two or more types.

When the dry etching method is used to form the infrared pass filter 12P, the constituent material of the infrared pass filter 12P is a curable composition containing a black pigment and an acrylic polymer. The curable composition does not need to be a photosensitive composition. The curable composition may further contain a transparent resin. The transparent resin is, for example, an acrylic resin, a polyamide resin, a polyimide resin, a polyurethane resin, a polyester resin, a polyether resin, a polyolefin resin, a polycarbonate resin, a polystyrene resin, or a norbornene resin. The infrared pass filter 12P is formed by film formation using a coating method or the like. The curable composition may also contain additives such as a curing agent, a crosslinking agent, and a leveling agent.

(Infrared cut filter)
The color filters for each of the above colors are organic color filters that do not have the function of cutting infrared light, so light outside the range of human visual sensitivity (for example, wavelengths longer than 700 nm) may enter the photoelectric conversion element, which causes a problem that the color of the subject captured by the imaging element may differ from the color of the subject observed by the human eye.

In order to avoid color separation that is affected by light outside the range of human visual sensitivity as described above, an infrared cut filter is used. That is, the infrared cut filter cuts out infrared light from the incident light. The light from which the infrared light has been cut is then made to enter each color filter, reducing the effects of infrared light.

The solid-state imaging device filter 10F of the present invention preferably includes an infrared cut filter 13 located further on the light incident side than the color filters 12R, 12G, and 12B for each of the multiple colors and the infrared pass filter 10P, and the infrared cut filter 13 includes a through hole 13H at a position overlapping the infrared pass filter 10P in a plan view.

By providing the through hole 13H, the infrared light incident on the infrared pass filter 12P is not cut off by the infrared cut filter 13. The infrared cut filter 13 cuts off the infrared light common to the red filter 12R, the green filter 12G, and the blue filter 12B.

When forming the infrared cut filter 13, a coating liquid containing an infrared cut dye and an acrylic polymer, and an organic solvent are applied onto the color filters 12R, 12G, 12B, and 12P, and the coating is dried. The dried coating is then thermally cured by post-baking. This forms the infrared cut filter 13.

The through-holes 13H in the infrared cut filter 13 are formed by a processing method such as patterning using photolithography or dry etching. When photolithography is used, the material constituting the infrared cut filter 13 is a photosensitive composition containing an infrared absorbing dye. The photosensitive composition contains a binder resin, a photopolymerization initiator, a polymerizable monomer, an organic solvent, a leveling agent, etc., and the materials listed as the constituent materials of the infrared pass filter 12P can be used.

When a dry etching method is used to form the through-hole 13H in the infrared cut filter 13, the constituent material of the infrared cut filter 13 is a curable composition containing an infrared absorbing dye, and includes a transparent resin. 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 coating method or the like. The curable composition may also contain additives such as a curing agent, a crosslinking agent, and a leveling agent.

(Barrier Layer)
The filter 10F for solid-state imaging devices of the present invention is provided with a barrier layer 14 that suppresses the transmission of an oxidation source that oxidizes the infrared pass filter 10P, located further on the light incident side than the color filters 12R, 12G, and 12B for each of the multiple colors and the infrared pass filter 10P, and it is preferable that the oxygen permeability of the barrier layer 14 is 5.0 cc/ ^m2 /day/atom or less.

The barrier layer 14 suppresses the transmission of oxidation sources to the infrared pass filter 12P. Oxidation sources include oxygen and water. The barrier layer 14 prevents the oxidation sources from reaching the infrared pass filter 12P, making the infrared pass filter 12P less susceptible to oxidation by the oxidation sources. This makes it possible to improve the light resistance of the infrared pass filter 12P.

The material forming the barrier layer 14 is an inorganic compound, and is preferably a silicon compound. The material forming such a barrier layer 14 is, for example, at least one selected from the group consisting of silicon nitride, silicon oxide, and silicon oxynitride.

The barrier layer 14 can be formed by a gas phase deposition method such as sputtering, CVD, or ion plating, or a liquid phase deposition method such as coating. For example, the barrier layer 14 made of silicon oxide is formed on the substrate on which the infrared cut filter 13 is formed by sputtering a target made of silicon oxide. For example, the barrier layer 14 made of silicon oxide is formed on the substrate on which the infrared cut filter 13 is formed by CVD using silane and oxygen. For example, the barrier layer 14 made of silicon oxide is formed by applying a coating liquid containing polysilazane, modifying it, and drying the coating.

It is preferable that the oxygen permeability, thickness, and visible light transmittance of the barrier layer 14 satisfy at least one of the following conditions [A1] to [A3].
[A1] The oxygen permeability in accordance with JIS K 7126-2006 is 5.0 cc/m ² /day/atom or less.
[A2] The barrier layer 14 has a thickness of 10 nm or more and 500 nm or less.
[A3] The barrier layer 14 has a visible light transmittance (average) of 90% or more.
If the configuration satisfies [A1], the arrival of an oxidation source, in particular oxygen, at the infrared pass filter 12P is sufficiently suppressed. From the viewpoint of further improving the light resistance of the infrared pass filter 12P, the oxygen permeability is preferably 3.0 cc/ ^m2 /day/atom or less, more preferably 1.0 cc/ ^m2 /day/atom or less, and even more preferably 0.7 cc/ ^m2 /day/atom or less.

If the configuration satisfies [A2], it is easy to select constituent materials that satisfy [A1] and [A3]. Furthermore, it is possible to prevent cracks from occurring in the barrier layer 14. If the configuration satisfies [A3], the absorption of visible light by the barrier layer 14 is sufficiently suppressed.

The layer structure of the barrier layer 14 may be a single layer structure made of a single compound, a laminated structure of layers made of a single compound, or a laminated structure of layers made of different compounds. For example, the barrier layer 14 may have a laminated structure in which layers that do not satisfy [A1] as a single layer are laminated to satisfy [A1].

In one embodiment of the solid-state imaging element of FIG. 1, the barrier layer 14 is positioned further on the light incident side than the infrared cut filter 13. This prevents the oxidation source from reaching the infrared cut filter 13 by the barrier layer 14, making the infrared cut filter 13 less susceptible to oxidation by the oxidation source. This improves the light resistance of the infrared cut filter 13, which means that the light resistance of the solid-state imaging element can be improved.

(Microlens)
The microlenses are composed of a red microlens 15R, a green microlens 15G, a blue microlens 15B, and an infrared microlens 15P. The red microlens 15R is on the light incident side of the red filter 12R, the green microlens 15G is on the light incident side of the green filter 12G, the blue microlens 15B is on the light incident side of the blue filter 12B, and the infrared microlens 15P is on the light incident side of the infrared pass filter 12P, all of which are located at positions where the microlenses and filters overlap in a plan view.

Each microlens 15R, 15G, 15B, and 15P has an incident surface 15S, which is the outer surface. Each microlens 15R, 15G, 15B, and 15P has a refractive index difference between itself and the outside air to focus the light that enters the incident surface 15S toward each photoelectric conversion element 11R, 11G, 11B, and 11P.

Each of the microlenses 15R, 15G, 15B, and 15P is formed by forming a coating film containing a transparent resin, patterning the coating film using a photolithography method, and reflowing the coating film by heat treatment. 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 may be a microlens. In this case, the microlens, which has the function of taking in light toward the photoelectric conversion element, also has the function of cutting infrared light, making it possible to simplify the layer structure of the filter for solid-state imaging elements.

The present invention will be described below based on examples, but the present invention is not limited thereto.
An infrared pass filter, a filter for a solid-state imaging device including the infrared pass filter, and the filter for a solid-state imaging device were prepared in the following order, and their durability was evaluated.

Example 1
(Preparation of Pigment Dispersion (hereinafter abbreviated as Dispersion) 1)
The perylene pigment, dispersant and solvent compositions were mixed together in the amounts shown below by weight in order to obtain a homogeneous mixture.
Colorant: Perylene pigment Lumogen Black K0088 manufactured by BASF: 12.0 parts Dispersant: Disperbyk-2001 manufactured by BYK Japan: 19.6 parts Solvent: Propylene glycol monomethyl ether acetate: 68.4 parts Then, using zirconia beads having a diameter of 0.1 mm, the mixture was dispersed for 1 hour using a Disper disperser DISPERMAT LC55 (manufactured by Eiko Seiki Co., Ltd.). Then, the mixture was filtered through a 5 μm filter to obtain Dispersion 1.

(Average Particle Size of Pigment Particles in Dispersion 1)
The average particle size (D50) of the pigment particles in the resulting Dispersion 1 was measured using a Nanotrac UPA-EX150 (manufactured by Nikkiso Co., Ltd.) and found to be 128 nm.

(Production of Acrylic Polymer 1)
60 parts by weight of propylene glycol monomethyl ether acetate (PGMAc) was prepared as a polymerization solvent, 40 parts by weight of phenyl methacrylate (C10H10O2) was prepared as an acrylic monomer, and 0.60 parts by weight of benzoyl peroxide (BPO) was prepared as a radical polymerization initiator. These were placed in a reaction vessel equipped with a stirrer and a reflux tube, and stirred and refluxed for 8 hours while introducing nitrogen gas into the reaction vessel and heating to 80°C. As a result, acrylic polymer 1 was obtained.

<Manufacture of infrared pass filter 1>
93.5 parts of the dispersion 1 and 6.5 parts of the acrylic polymer 1 were mixed, stirred with a stirrer for 1 hour, and then filtered through a 5 μm filter to obtain a curable composition 1. The curable composition 1 was applied onto a glass substrate with a spin coater so that the film thickness after post-baking would be 1 μm, and then dried on a hot plate at 70° C. for 1 minute, and then further post-baked on a hot plate at 230° C. for 3 minutes to obtain an infrared pass filter 1 containing 50% by weight of a perylene pigment.

<Evaluation of Infrared Pass Filter 1>
The spectral transmittance of the infrared pass filter 1 formed on the glass for light with wavelengths of 400 to 1100 nm was measured using a spectrophotometer U-4100 (manufactured by Hitachi High-Technologies Corporation). As a result, the average transmittance of light in the visible region of 400 to 800 nm was 19%, and the average transmittance of light in the near-infrared region of 900 to 1000 nm was 86%. It was found to be a good infrared pass filter that can block light in the visible region that becomes noise and transmit light in the near-infrared region.

The infrared pass filter 1 formed on the glass was then further heat-treated on a hot plate at 250°C for 10 minutes, after which the spectral transmittance of light with wavelengths of 400 to 1100 nm was measured using a spectrophotometer U-4100 (Hitachi High-Technologies Corporation). Compared to before the heat treatment, the average transmittance of light from 400 to 800 nm changed by 0.1%, and the average transmittance of light from 900 to 1000 nm changed by 1.4%. The spectral transmittance curves before and after the treatment almost overlapped, demonstrating that this is an infrared pass filter with extremely high heat resistance.

After irradiating the infrared pass filter 1 formed on glass with 100,000 lux of light from a xenon lamp for 24 hours, the spectral transmittance of light with wavelengths of 400 to 1100 nm was measured using a spectrophotometer U-4100 (Hitachi High-Technologies Corporation). Compared to before treatment, the average transmittance of light from 400 to 800 nm changed by 0.5%, and the average transmittance of light from 900 to 1000 nm changed by 0.8%. The spectral transmittance curves before and after treatment overlapped, demonstrating that this is an infrared pass filter with extremely high light resistance.

(Evaluation of Barrier Layer)
As a preliminary test, a barrier layer made of silicon oxide with a thickness of 50 nm was formed on a PET film by a CVD method using silane and oxygen. The oxygen permeability of the formed barrier layer was measured using an oxygen permeability measuring device OX-TRAN (manufactured by MOCON Corporation) and was confirmed to be 1.1 cc/ ^m2 /day/atom.

<Production and evaluation of filters for solid-state imaging devices>
A barrier layer formed under the same conditions as above was laminated on the infrared pass filter 1 formed on glass to form a filter for solid-state imaging devices without microlenses. The infrared pass filter 1 was irradiated with light of 100,000 lux from a xenon lamp for 200 hours, and then the spectral transmittance of light with wavelengths of 400 to 1100 nm was measured using a spectrophotometer U-4100 (manufactured by Hitachi High-Technologies Corporation). Compared to before the treatment, the change in the average transmittance of light from 400 to 800 nm was 0.3%, and the change in the average transmittance of light from 900 to 1000 nm was 0.4%. The spectral transmittance curves before and after the treatment also overlapped, and it was found that laminating a barrier layer resulted in a filter for solid-state imaging devices with even higher light resistance.

Example 2
(Preparation of Dispersion 2 and Average Particle Size)
A mixture produced under the same conditions as Dispersion 1 described in Example 1 above was stirred and mixed to become uniform, and then dispersed for 1 hour using glass beads with a diameter of 1 mm in a paint shaker (manufactured by Asada Iron Works Co., Ltd.). The mixture was then filtered through a 5 μm filter to obtain Dispersion 2. The average particle size (D50) of the pigment particles in the obtained Dispersion 2 was measured using a Nanotrac UPA-EX150 (manufactured by Nikkiso Co., Ltd.) and found to be 233 nm.

<Manufacture of infrared pass filter 2>
93.5 parts of the dispersion 2 and 6.5 parts of the acrylic polymer 1 described in Example 1 were mixed, stirred with a stirrer for 1 hour, and then filtered through a 5 μm filter to obtain a curable composition 2. The curable composition 2 was applied onto a glass substrate with a spin coater, dried on a hot plate at 70° C. for 1 minute, and then post-baked on a hot plate at 230° C. for 3 minutes to obtain an infrared pass filter 2 containing 50% by weight of a perylene pigment.

<Evaluation of Infrared Pass Filter 2>
The spectral transmittance of the infrared pass filter 2 formed on the glass for light with wavelengths of 400 to 1100 nm was measured using a spectrophotometer U-4100 (manufactured by Hitachi High-Technologies Corporation). As a result, the average transmittance of light in the visible region of 400 to 800 nm was 14%, and the average transmittance of light in the near-infrared region of 900 to 1000 nm was 79%. It was found to be a good infrared pass filter that can block light in the visible region that becomes noise, and can transmit light in the near-infrared region.

<Comparative Example 1>
When the dispersion time was extended to 3 hours in the manufacturing method of Dispersion 1 described in Example 1 above, the dispersion liquid became highly viscous during dispersion, i.e., the dispersion liquid gelled due to excessive dispersion, and the viscosity did not decrease even when a solvent was added thereafter, and the coating liquid became unstable, making it impossible to evaluate thereafter. In other words, it was found that it was not possible to manufacture a dispersion with an average particle size of less than 50 nm.

<Comparative Example 2>
(Preparation of Dispersion 3 and Average Particle Size)
The perylene pigment, dispersant and solvent compositions were mixed together in the amounts shown below by weight in order to obtain a homogeneous mixture.
Colorant: Perylene pigment Lumogen Black K0088 manufactured by BASF: 14.5 parts Dispersant: Disperbyk-2001 manufactured by BYK Japan: 15.8 parts Solvent: Propylene glycol monomethyl ether acetate: 69.7 parts Then, using glass beads having a diameter of 1 mm, the mixture was dispersed for 1 hour using a paint shaker (manufactured by Asada Iron Works). Then, the mixture was filtered through a 5 μm filter to obtain Dispersion 3. The average particle size (D50) of the pigment particles in the obtained Dispersion 3 was measured using Nanotrac UPA-EX150 (manufactured by Nikkiso Co., Ltd.), and it was found that the average particle size was as large as 334 nm. It was found that the amount of dispersant was too small relative to the pigment, resulting in a poor dispersion state and a particle size larger than 300 nm.

<Manufacture and Evaluation of Infrared Pass Filter 3>
85 parts of the dispersion 3 and 15 parts of the acrylic polymer 1 were mixed, stirred with a stirrer for 1 hour, and filtered with a 5 μm filter to obtain a curable composition 3. The curable composition 3 was applied to a glass substrate with a spin coater, dried on a hot plate at 70 ° C. for 1 minute, and then post-baked on a hot plate at 230 ° C. for 3 minutes to obtain an infrared pass filter 3 containing 50 wt % of perylene pigment. It was observed that the infrared pass filter 3 formed on the glass had a cloudy film (matte black) and had large surface unevenness. Since the average particle diameter of the dispersion 3, which is the composition of the infrared pass filter 3, is also 334 nm, which is larger than 300 nm, it was found that when the film was formed, surface unevenness was generated, and incident light was reflected and scattered, resulting in a decrease in light transmittance. It was also found that the solid-state imaging element using the infrared pass filter 3 had a reduced amount of infrared light that could be detected by the infrared light photoelectric conversion element, resulting in a solid-state imaging element with low detection accuracy.

<Comparative Example 3>
(Preparation and average particle size of dispersion 4)
The perylene pigment, dispersant and solvent compositions were mixed together in the amounts shown below by weight in order to obtain a homogeneous mixture.
Colorant Perylene pigment BASF Lumogen Black K0088: 22.0 parts Dispersant BYK Japan Disperbyk-2001: 19.6 parts Solvent Propylene glycol monomethyl ether acetate: 68.4 parts Then, using zirconia beads with a diameter of 0.1 mm, the dispersion was dispersed for 1 hour using a Disper disperser DISPERMATLC55 (manufactured by Eiko Seiki Co., Ltd.), and the dispersion gelled (became highly viscous) and could not be filtered through a 5 μm filter. The average particle size (D50) of the pigment particles in the obtained Dispersion 4 was measured using Nanotrac UPA-EX150 (manufactured by Nikkiso Co., Ltd.), and it was found that the average particle size was as large as 342 nm. This is because in Dispersion 4, in which the amount of dispersant is too small relative to the pigment, the perylene pigment concentration was 71% by weight, which is higher than 70% by weight, and dispersion was not possible.

<Manufacture and Evaluation of Infrared Pass Filter 4>
The above dispersion 4 was applied to a glass substrate by a spin coater, dried on a hot plate at 70°C for 1 minute, and then post-baked on a hot plate at 230°C for 3 minutes to obtain an infrared pass filter 4. As in Comparative Example 2, the infrared pass filter 4 had a cloudy (matte black) film and was found to have large surface irregularities. Since the average particle size of the dispersion 4, which is the composition of the infrared pass filter 4, is 342 nm and larger than 300 nm, it was found that the surface irregularities were generated when the film was formed, and the incident light was reflected and scattered, resulting in a decrease in the light transmittance. It was also found that the solid-state imaging element using the infrared pass filter 4 had a reduced amount of infrared light that the infrared light photoelectric conversion element could detect, resulting in a solid-state imaging element with low detection accuracy.

<Comparative Example 4>
<Manufacture and Evaluation of Infrared Pass Filter 5>
79 parts of the dispersion 1 and 21 parts of the acrylic polymer 1 were mixed, stirred with a stirrer for 1 hour, and then filtered through a 5 μm filter to obtain a curable composition 4. The curable composition 4 was applied onto a glass substrate with a spin coater so that the film thickness after post-baking would be 1 μm, and then dried on a hot plate at 70° C. for 1 minute, and then further post-baked on a hot plate at 230° C. for 3 minutes to obtain an infrared pass filter 5.

The spectral transmittance of the infrared pass filter 5 formed on the glass at wavelengths of 400 to 1100 nm was measured using a spectrophotometer U-4100 (Hitachi High-Technologies Corporation). As a result, the average transmittance of light in the visible region of 400 to 800 nm was 33%, and the average transmittance of light in the near-infrared region of 900 to 1000 nm was 95%. Since the amount of dispersion 1 was small at 79 parts, it was found that the infrared pass filter 5, which had a perylene pigment concentration of 38% by weight, less than 40% by weight, was an infrared pass filter that could not sufficiently block light in the visible region. It was found that the solid-state imaging element using the infrared pass filter 5 could not sufficiently block light in the visible region, and therefore also detected visible light that would cause noise in the infrared light photoelectric conversion element, resulting in a solid-state imaging element with low detection accuracy.

10...Solid-state imaging element (one unit)
10F: filter for solid-state imaging element 11: photoelectric conversion element 11R: red photoelectric conversion element 11G: green photoelectric conversion element 11B: blue photoelectric conversion element 11P: infrared photoelectric conversion element 12R: red color filter (red filter)
12G: Green color filter (green filter)
12B: Blue color filter (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 microlens 15S... incident surface

Claims (9)

The infrared pass filter is an optical filter that blocks light in the visible region and transmits light in the near-infrared region, and contains only a perylene pigment having an average particle size of 50 to 300 nm as a black coloring material , with the content of the perylene pigment being 40 to 70% by weight. 2. The infrared pass filter according to claim 1, wherein the perylene pigment has an average particle size of 128 to 300 nm. The infrared pass filter according to claim 1 or 2, in which the average transmittance of light in the visible region and part of the near infrared region at wavelengths of 400 to 800 nm is 30% or less, and the average transmittance of light in the near infrared region at wavelengths of 900 to 1000 nm is 70% or more. The infrared pass filter according to any one of claims 1 to 3, which contains an acrylic polymer. The infrared pass filter according to claim 4, wherein the acrylic polymer is an acrylic polymer derived from phenyl methacrylate. A filter for a solid-state imaging device, comprising a plurality of color filters for each color and the infrared pass filter according to any one of claims 1 to 5, positioned on the light incident side of a photoelectric conversion element. 7. The filter for a solid- state imaging element according to claim 6 , further comprising an infrared cut filter at a position on the light incident side further than the color filters for each of the plurality of colors and the infrared pass filter, and the infrared cut filter has a through hole at a position overlapping the infrared pass filter in a planar view. 8. The filter for a solid-state imaging device according to claim 6 , further comprising a barrier layer for suppressing transmission of an oxidation source that oxidizes the infrared pass filter, the barrier layer being disposed on the light incident side of the color filters for each of the plurality of colors and the infrared pass filter, the oxygen permeability of the barrier layer being 5.0 cc/ ^m2 /day/atom or less. A solid-state imaging device comprising: a plurality of photoelectric conversion elements; and the filter for solid-state imaging devices according to any one of claims 6 to 8.