JP3904028B2 - Wavelength selective absorption filter - Google Patents

Description

  The present invention relates to an optical filter that absorbs near-infrared light and neon light, and more specifically, has a wide and large absorption in the near-infrared region, absorbs neon light, and transmits light in other visible light regions. The present invention relates to a wavelength selective absorption filter that is high in durability and has excellent durability with little change in optical characteristics over time even when stored at high temperature and high humidity.

  An optical filter having near-infrared absorption ability has a property of blocking near-infrared light and allowing visible light to pass therethrough, and is used in various applications.

  In recent years, plasma displays have attracted attention as thin, large-screen displays. However, there is a problem that electronic devices that use near-infrared remote controls malfunction due to near-infrared rays emitted from plasma displays. A filter is provided.

  As a near-infrared absorption filter, (1) a filter containing metal ions such as copper or iron on phosphoric acid glass, and (2) a layer having a different refractive index is laminated, and a specific wavelength is set by causing interference with transmitted light. Proposed interference filters, (3) acrylic resin filters containing copper ions in copolymers, and (4) filters in which a layer in which an infrared absorbing dye is dispersed or dissolved in a resin are laminated.

Among these, the filter (4) has good processability and productivity, and has a relatively large degree of freedom in optical design, and therefore various methods for producing the filter have been proposed (for example, Patent Document 1). To 9).
JP 2002-82219 A JP 2002-214427 A JP 2002-303720 A JP 2002-333517 A JP 2003-82302 A Japanese Patent Laid-Open No. 2003-96040 Japanese Patent Laid-Open No. 11-305033 JP-A-11-326629 Japanese Patent Laid-Open No. 11-326631 JP 2000-227515 A JP 2002-264278 A International Publication No. 97/38855 Pamphlet JP 2003-114323 A JP 2002-138203 A

  Some of these methods have the ability to sufficiently block the near-infrared rays emitted from the plasma display. However, when used for a long time under high temperature and high humidity, the optical properties are not stable over time. there were.

  As a method to suppress the temporal stability of the optical characteristics when used for a long time under high temperature and high humidity, the glass transition temperature of the resin constituting the near infrared absorption layer is higher than the guaranteed use temperature of the equipment using the near infrared absorption filter (For example, refer to Patent Documents 7 to 10) and a method for reducing the amount of residual solvent in the near-infrared absorbing layer (for example, refer to Patent Documents 10 and 11).

  In addition, it is known that aromatic diimmonium compound-based dyes used as near-infrared absorbing dyes are generally vulnerable to heat (see, for example, page 17 of Patent Document 12).

  Therefore, as a technique for suppressing dye alteration due to heat in a near-infrared absorbing layer containing a diimmonium compound, the diimmonium compound is purified and a specific diimmonium compound having an endothermic peak at a temperature of 220 ° C. or higher in DSC measurement. Have also been proposed (for example, see Patent Document 13), a method for containing a diimmonium compound having a melting point of 190 ° C. or higher in the near-infrared shielding layer (for example, see Patent Document 14), and the like. Yes.

  Furthermore, since the plasma display also emits neon orange light (wavelength of around 600 nm), there is a problem that the vivid color rendering property and the sharpness of the image of the display are impaired only by maintaining the temporal stability of the near infrared absorption layer. there were.

  The purpose of the present invention is to change optical characteristics over time in a selective absorption optical filter that has a large and broad absorption in the near infrared region, absorbs neon light, and has a high light transmittance in other visible light regions. The object of the present invention is to provide a wavelength-selective absorption filter having a small amount and excellent durability.

  As a result of intensive studies to solve the above problems, the present inventors have finally completed the present invention. That is, the present invention is as follows.

The first invention uses a polyester-based film as a transparent substrate, and a single-layer or multiple-layer wavelength-selective absorption layer containing a resin, a near-infrared absorbing dye (A), and a dye (B) on the transparent substrate. A wavelength-selective absorption filter having a maximum absorption at a wavelength of 800 to 1200 nm and a wavelength of 550 to 620 nm,
One of the near-infrared absorbing dyes (A) is an aromatic diimmonium dye (a) having bis (trifluoromethanesulfonyl) imidic acid as a counter ion,
One of the dyes (B) is a porphyrin dye or an azaporphyrin dye (b).

  In the second invention, the multi-layer wavelength selective absorption layer includes a near-infrared absorption layer containing a resin and a near-infrared absorption dye (A), and a neon cut layer containing a resin and a dye (B) in this order. The wavelength selective absorption filter according to the first invention, wherein the wavelength selective absorption filter is formed on a material.

  In a third invention, the wavelength selective absorption layer contains 5 to 100 parts by mass (mass ratio) of the porphyrin dye or azaporphyrin dye (b) with respect to 100 parts by mass of the aromatic diimmonium dye (a). A wavelength selective absorption filter according to the first aspect of the invention.

  A fourth invention is the wavelength selective absorption filter according to the first invention, wherein the resin constituting the wavelength selective absorption layer is an acrylic resin.

  In a fifth aspect of the invention, the single wavelength selective absorption layer contains an organic solvent, a resin, an aromatic diimmonium dye (a), a porphyrin dye or an azaporphyrin dye (b) on the transparent substrate. The wavelength selective absorption filter according to the first invention, wherein the coating liquid A is formed by coating and drying.

  In a sixth aspect of the present invention, a multilayer wavelength selective absorption layer is formed by applying and drying a coating liquid B containing an organic solvent, a resin, and an aromatic diimmonium dye (a) on the transparent substrate. The formed near-infrared absorbing layer, and a coating liquid C containing an organic solvent and a resin and a porphyrin-based dye or an azaporphyrin-based dye (b) are formed by coating and drying immediately above the near-infrared absorbing layer. The wavelength selective absorption filter according to the first aspect of the invention is characterized by including a neon cut layer.

  A seventh invention is the wavelength selective absorption filter according to the fifth or sixth invention, wherein the coating liquid A or B further contains a surfactant having an HLB of 2 to 12.

An eighth invention is the wavelength selective absorption filter according to the seventh invention, wherein the surfactant is a silicone surfactant or a fluorine surfactant.
A ninth invention is the wavelength selective absorption filter according to any one of the first to eighth inventions, wherein an intermediate layer containing particles is provided between the transparent substrate and the wavelength selective absorption layer.
According to a tenth aspect, in the ninth aspect, the particles are selected from silica, kaolinite, talc, calcium carbonate, zeolite, alumina, acrylic, PMMA, nylon, styrene, polyester, and benzoguanamine / formalin condensate. The wavelength selective absorption filter described in 1.

  When the wavelength selective absorption filter according to the present invention is installed on the front surface of the plasma display, it can absorb unnecessary near-infrared rays emitted from the display and prevent the malfunction of precision instruments as in the case of the conventional wavelength selective absorption filter. In addition, since unnecessary neon light is absorbed, the sharpness of the image is high, and the change due to temperature and humidity is small, and it is possible to reduce the temporal change of the high quality of the plasma display.

  The wavelength selective absorption filter of the present invention is formed by laminating a single-layer or multiple-layer wavelength selective absorption layer containing a resin, a near-infrared absorbing dye (A), and a dye (B) on a transparent substrate, And it is a wavelength selective absorption filter which has maximum absorption in wavelength 800-1200 nm and wavelength 550-620 nm, Comprising: One of the said near-infrared absorption pigment | dyes (A) is aromatic which uses bis (trifluoromethanesulfonyl) imido acid as a counter ion It is a diimmonium dye (a), and is characterized in that one of the dyes (B) is a porphyrin dye or an azaporphyrin dye (b).

Hereinafter, the present invention will be described in detail.
(Transparent substrate)
In the present invention, the transparent substrate is not particularly limited, but preferably has a total light transmittance of 80% or more and a haze of 5% or less. When the substrate is inferior in transparency, not only the brightness of the display is lowered, but the sharpness of the image becomes poor.

  Examples of such transparent substrates include polyester-based, acrylic-based, cellulose-based, polyethylene-based, polypropylene-based, polyolefin-based, polyvinyl chloride-based, polycarbonate, phenol-based, urethane-based plastic films or sheets, glass, and the like. The thing which bonded two or more arbitrary types of these is mentioned. A polyester film having a good balance between heat resistance and flexibility is preferable, and a polyethylene terephthalate film is more preferable.

  Polyester film suitable as a transparent substrate for use in the present invention, as dicarboxylic acid component, aromatic dicarboxylic acid or ester thereof such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, and glycol component, ethylene glycol, diethylene glycol, The polyester chip obtained by performing esterification reaction or transesterification reaction using 1,4-butanediol, neopentyl glycol, etc., and then polycondensation reaction is dried and then melted in an extruder, and converted from a T die to a sheet. It is a film produced by stretching an unstretched sheet obtained by extrusion in at least one axial direction, followed by heat setting treatment and relaxation treatment.

  The film is particularly preferably a biaxially stretched film from the viewpoint of strength. Examples of the stretching method include a tubular stretching method, a simultaneous biaxial stretching method, a sequential biaxial stretching method, and the like, but a sequential biaxial stretching method is preferable in view of flatness, dimensional stability, thickness unevenness, and the like. The sequential biaxially stretched film is, for example, roll-stretched in the longitudinal direction at a glass transition temperature (Tg) or higher (Tg + 30 ° C. or lower) of the polyester in the longitudinal direction at a magnification of 2.0 to 5.0 times. Subsequently, after preheating with a tenter, the film is stretched in the width direction at a temperature of 120 ° C. or more and 150 ° C. or less and a magnification of 1.2 times or more and 5.0 times or less. Further, the biaxially stretched film is subjected to heat setting treatment at a temperature of 220 ° C. or higher (melting point −10 ° C. or lower). Next, by relaxing 3% to 8% in the width direction, a polyester film suitable as a transparent substrate used in the present invention can be produced. Further, in order to further improve the dimensional stability in the longitudinal direction of the film, a longitudinal relaxation treatment may be used in combination.

  In order to provide the film with handleability (for example, rollability after lamination), it is preferable to incorporate particles and form protrusions on the film surface. As particles to be included in the film, inorganic particles such as silica, kaolinite, talc, calcium carbonate, zeolite, alumina, etc., heat resistant polymer particles such as acrylic, PMMA, nylon, polystyrene, polyester, benzoguanamine / formalin condensate, etc. Is mentioned. From the viewpoint of transparency, the content of particles in the film is preferably small, for example, preferably 1 ppm or more and 1000 ppm or less. Furthermore, it is preferable to select particles having a refractive index close to that of the resin used from the viewpoint of transparency. Moreover, in order to provide various functions as needed, the film may contain a light-resistant agent (ultraviolet ray inhibitor), a pigment, an antistatic agent, and the like.

  The transparent substrate used in the present invention may be a single layer film or a composite film of two or more layers in which a surface layer and a center layer are laminated. In the case of a composite film, there is an advantage that the functions of the surface layer and the center layer can be designed independently. For example, by containing particles only on the thin surface layer and forming irregularities on the surface, the handling property is maintained, but the thick central layer does not substantially contain particles, so that the composite film as a whole is transparent. Can be further improved. The method for producing the composite film is not particularly limited. However, in consideration of productivity, the raw material for the surface layer and the central layer are extruded from separate extruders, led to one die, and after obtaining an unstretched sheet, at least It is particularly preferable to produce by a so-called coextrusion method in which it is oriented in a uniaxial direction.

  Although the thickness of a transparent base material changes with raw materials, when using a polyester film, 35 micrometers or more are preferable, More preferably, it is 50 micrometers or more. On the other hand, the thickness is preferably 260 μm or less, more preferably 200 μm or less. When the thickness is small, not only the handling property becomes poor, but also when heated at the time of drying to reduce the amount of residual solvent in the wavelength selective absorption layer, heat wrinkles occur on the film, resulting in poor flatness. Cheap. On the other hand, when the thickness is large, not only is there a problem in terms of cost, but flatness due to curling tends to occur when the material is wound and stored in a roll shape.

(Middle layer)
The wavelength selective absorption filter of the present invention has a structure in which a single layer or multiple layers of a wavelength selective absorption layer is laminated on a transparent substrate. An intermediate layer may be provided for the purpose of improving the transparency of the substrate. In addition, when not containing particle | grains in a film, high transparency can be obtained, maintaining handling property by providing the intermediate | middle layer containing particle | grains simultaneously at the time of film manufacture.

  Examples of the resin constituting the intermediate layer include polyester resins, polyurethane resins, polyester urethane resins, acrylic resins, melamine resins, etc., so that the adhesion to the substrate and the wavelength selective absorption layer is good. It is important to select, for example, if the resin constituting the substrate and the wavelength selective absorption layer is an ester, it is preferable to select a polyester or polyester urethane having a similar structure.

  The intermediate layer may contain a crosslinking agent for the purpose of improving adhesion and improving water resistance to form a crosslinked structure. Examples of the crosslinking agent include urea, epoxy, melamine, and isocyanate. In particular, when the resin undergoes whitening or strength reduction under high temperature and high humidity, the effect of the crosslinking agent is remarkable. Instead of using a crosslinking agent, a graft copolymer resin having self-crosslinking property may be used as the resin.

  The intermediate layer may contain various kinds of particles for the purpose of forming irregularities on the surface and improving slipperiness. Examples of the particles to be included in the intermediate layer include inorganic particles such as silica, kaolinite, talc, calcium carbonate, zeolite, and alumina, organic materials such as acrylic, PMMA, nylon, styrene, polyester, and benzoguanamine / formalin condensate. Particles. In addition, it is preferable to select particles having a refractive index close to that of the resin used from the viewpoint of transparency.

  Furthermore, in order to give various functions to the intermediate layer, a surfactant, an antistatic agent, a dye, an ultraviolet absorber, or the like may be contained.

  The intermediate layer may be a single layer if it has the desired function, but may be laminated in two or more layers as necessary.

  The thickness of the intermediate layer is not particularly limited as long as it has a desired function, but is preferably 0.01 μm or more and 5 μm or less. When the thickness is small, the function as an intermediate layer is hardly exhibited. On the contrary, when the thickness is thick, the transparency tends to be poor.

  The intermediate layer is preferably provided by a coating method. As the coating method, using a known coating method such as gravure coating method, kiss coating method, dip method, spray coating method, curtain coating method, air knife coating method, blade coating method, reverse roll coating method, etc. An in-line coating method in which a coating layer is provided, an offline coating method in which a coating layer is provided after film production, and the like can be employed. Among these methods, the in-line coating method not only excels in cost, but also makes the coating layer contain particles so that it is not necessary to contain particles in the transparent base material, so that the transparency is highly improved. Is preferable.

(Wavelength selective absorption layer)
In the wavelength selective absorption filter of the present invention, a wavelength selective absorption layer composed of a single layer or a multi-layer structure including a dye having near infrared absorption ability is laminated on a transparent substrate directly or via an intermediate layer.

  The near-infrared absorbing dye is a dye having a maximum absorption in the near-infrared region having a wavelength of 800 nm or more and 1200 nm or less. Examples include naphthoquinone, pyrylium, thiopyrylium, squarylium, croconium, tetradehydrocholine, triphenylmethane, cyanine, azo, and aminium compounds. These compounds are used alone or in admixture of two or more. In the present invention, the following formula (I) has a large absorption in the near infrared region, a wide absorption region, and a high transmittance in the visible light region. It is necessary to contain the diimonium salt compound shown by this.

Specific examples of R ^{1 to} R ⁸ in the general formula (I) include (1) methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, tert -Butyl group, n-amyl group, n-hexyl group, n-octyl group, 2-hydroxyethyl group, 2-cyanoethyl group, 3-hydroxypropyl group, 3-cyanopropyl group, methoxyethyl group, ethoxyethyl group, Alkyl groups such as butoxyethyl groups, (2) aryl groups such as phenyl groups, fluorophenyl groups, chlorophenyl groups, tolyl groups, diethylaminophenyl, naphthyl groups, (3) vinyl groups, propenyl groups, butenyl groups, pentenyl groups, etc. Alkenyl group, (4) benzyl group, p-fluorobenzyl group, p-chlorophenyl group, phenylpropyl group, naphthylethyl group, etc. Aralkyl group, and the like.

R ^{9 to} R ¹² include hydrogen, fluorine, chlorine, bromine, diethylamino group, dimethylamino group, cyano group, nitro group, methyl group, ethyl group, propyl group, trifluoromethyl group, methoxy group, and ethoxy group. And propoxy group.

In the formula (I), X ⁻ represents fluorine ion, chlorine ion, bromine ion, iodine ion, perchlorate ion, hexafluoroantimonate ion, hexafluorophosphate ion, tetrafluoroborate ion, bis (trifluoromethane) Sulfonyl) imido ion and the like. In the present invention, since an azaporphyrin-based dye or the like is used as a neon cut dye (described later), it is necessary to include a near-infrared absorbing dye in which X ⁻ is a bis (trifluoromethanesulfonyl) imido ion. This compound is commercially available, and examples thereof include CIR-1085 and CIR-RL manufactured by Nippon Carlit, and IRG-068 manufactured by Nippon Kayaku.

  In addition to the diimonium salt compound represented by the above formula (I), the wavelength selective absorption filter of the present invention can be added with other near infrared absorbing dyes for the purpose of expanding and adjusting the absorption region in the near infrared region. . Preferably, those that do not promote the deterioration of the diimmonium salt dye are specifically mentioned, and specific examples include phthalocyanine, cyanine dye, and dithiol metal complex systems having an absorption peak at 800 nm or more and 1200 nm or less.

In the present invention, in order to control the target absorption in the near-infrared region and the transmittance in the visible light region, the amount of the near-infrared-absorbing dye is 0.01 g / in any surface in the thickness direction of the wavelength selective absorption layer. it is preferably adjusted so that m ² or more 1.0 g / m ² or less. When the amount of the near-infrared absorbing dye is small, the absorption ability in the near-infrared region is insufficient, and conversely, when it is large, the transparency in the visible light region is insufficient and the brightness of the display is lowered. .

  In the present invention, the wavelength selective absorption layer needs to contain a neon cut dye. The plasma display emits so-called neon orange light centered around 600 nm, and has a drawback that a bright red color cannot be obtained because the orange color is mixed with the red color. By including a neon cut pigment, the above problem can be solved.

  In the present invention, the neon cut dye is a dye having a maximum absorption in a wavelength range of 550 nm or more and 620 nm or less. Specifically, cyanine, squarylium, azomethine, xanthene, oxonol, azo, phthalocyanine Quinone, azurenium, pyrylium, croconium, dithiol metal complex, pyromethene, azaporphyrin, and the like. These dyes can be used alone or in admixture of two or more. In the present invention, it is necessary to use a porphyrin dye or an azaporphyrin dye.

A porphyrin pigment or an azaporphyrin pigment is a pigment represented by the following formulas (II) and (III). Specific examples of R ^{11 to} R ¹⁴ and R ^{15 to} R ²² in formula (II) and formula (III) are hydrogen atom, halogen atom, nitro group, cyano group, hydroxy group, amino group, carboxyl group, sulfonic acid Group, alkyl group having 1 to 20 carbon atoms, halogenoalkyl group, alkoxy group, alkoxyalkoxy group, aryloxy group, monoalkylamino group, dialkylamino group, aralkyl group, aryl group, heteroaryl group, alkylthio group, or An arylthio group is mentioned, and each may independently form a ring excluding an aromatic ring via a linking group. M includes two hydrogen atoms, a divalent metal atom, a trivalent mono-substituted metal atom, a tetravalent di-substituted metal atom, or an oxy metal atom.

  This compound is available as a commercial product, and examples thereof include TAP-2, TAP-5, TAP-9, TAP-10, TAP-12 manufactured by Yamada Chemical Industry, PD-319, PD-311 manufactured by Mitsui Chemicals. It is done.

The neon-cut dye content is adjusted so that the obtained wavelength selective absorption filter has sharp absorption in the wavelength region of 550 nm to 620 nm and the transmittance at the maximum absorption wavelength is 30% or less. It is preferable to do this. Specifically, on a transparent substrate, it is preferable to present the neon-cut dye 0.001 g / m ² or more 0.1 g / m ² or less.

  In the present invention, the wavelength selective absorption layer is composed of a single layer or multiple layers. As the wavelength selective absorption layer, two types of dyes, the aromatic diimmonium dye (a) having bis (trifluoromethanesulfonyl) imidic acid as a counter ion and the porphyrin dye or azaporphyrin dye (b), are applied in the same manner. It is preferable to have a single layer structure mixed in the layer.

  In the present invention, an aromatic diimmonium dye having bis (trifluoromethanesulfonyl) imidic acid as a counter ion as a near-infrared absorbing dye and a porphyrin dye or azaporphyrin dye as a neon cut dye in a single wavelength selective absorption layer The reason why it is essential to adopt is that mixing these two kinds of pigments in the same coating layer provides an effect of improving the durability of the wavelength selective absorption layer. Although the mechanism for improving durability is not clear, bis (trifluoromethanesulfonyl) imidic acid, which is a counter ion of diimmonium dye, and azaporphyrin dye (or porphyrin dye) have some interaction, and humidity and It is estimated that the deterioration of the dye due to temperature can be suppressed.

  Moreover, in this invention, as a wavelength selection absorption layer, the near-infrared absorption layer containing resin and a near-infrared absorption pigment | dye (A), and the neon cut layer containing resin and pigment | dye (B) are in this order on a transparent base material. A wavelength selective absorption layer having a multilayer structure formed can be used. A multilayer comprising a layer containing an aromatic diimmonium dye (a) and a porphyrin dye or azaporphyrin dye (b) each containing bis (trifluoromethanesulfonyl) imidic acid as a counter ion as a wavelength selective absorption layer. Also with the configuration, the effect of improving the durability can be obtained as in the case of the single wavelength selective absorption layer. The reason for this is not clear, but the interaction between the dye (a) and the dye (b) works at the interface between the near-infrared absorbing layer and the neon cut layer, and the movement of the dye occurs at the interface, and the same layer The same effect as in the case where the pigment (a) and the pigment (b) are present in the glass is obtained.

  The azaporphyrin-based dye (or porphyrin-based dye) is preferably contained in the diimmonium-based dye in an amount of 5 parts by mass or more, more preferably 10 parts by mass or more, with respect to 100 parts by mass. The upper limit is preferably 100 parts by mass, more preferably 50 parts by mass or less. When the ratio of the azaporphyrin dye to the aromatic diimmonium dye is not in the preferred range, the above-mentioned interaction does not work and it may be difficult to improve the durability.

  In the present invention, the near-infrared absorbing dye or the neon cut dye is laminated on the transparent substrate by a coating method in a state of being dispersed or dissolved in the resin. The resin is not particularly limited as long as it can dissolve or disperse the near-infrared absorbing dye or neon cut dye uniformly, but a polyester-based, acrylic-based, polyamide-based, polyurethane-based, polyolefin-based, or polycarbonate-based resin is preferably used. Can be used. Among them, an acrylic resin excellent in transparency, heat resistance, and solvent resistance at the time of dye mixing is preferable, and in particular, when using a diimmonium dye having bis (trifluoromethanesulfonyl) imidic acid as a counter ion, It is preferable to employ an acrylic resin from the viewpoint of the adhesion of the resin and the affinity with the pigment.

  Moreover, it is preferable that the glass transition temperature of said resin is more than the use guarantee temperature of the apparatus in which the wavelength selection absorption filter is used. When the glass transition temperature of the resin is equal to or lower than the operating temperature of the device in which the wavelength selective absorption filter is used, the pigments dispersed in the resin are likely to react with each other, and the resin absorbs moisture in the outside air. Deterioration of dyes and resins increases. In the present invention, the glass transition temperature of the resin is not particularly limited as long as it is equal to or higher than the operating temperature of the equipment in which the wavelength selective absorption filter is used, but it is particularly preferably 85 ° C. or higher and 160 ° C. or lower.

  When the glass transition temperature of the resin is less than 85 ° C., the interaction between the dye and the resin, the interaction between the dyes, and the like occur, and the modification of the dye occurs. If the glass transition temperature exceeds 160 ° C., the resin must be dissolved in a solvent and heated to a sufficient temperature when applied on a transparent substrate. Poor property and further deterioration of the dye occurs. Moreover, when drying at low temperature, since drying requires a long time, productivity will worsen and productivity will become bad. In addition, there is a possibility that sufficient drying cannot be performed, and when the solvent remains in the coating film in a large amount, it is the same as when the above-mentioned glass transition temperature is equal to or lower than the operating temperature of the device in which the wavelength selective absorption filter is used. Furthermore, it causes modification of diimmonium salt pigments with poor durability.

  When a wavelength selective absorption layer having a multilayer structure is used, the resin used for the neon cut layer is different from the diimmonium salt dye, and the porphyrin dye or azaporphyrin dye (b) itself has excellent durability. Therefore, the influence of the glass transition temperature and drying conditions of the resin is small. However, when a resin having a strong polarity such as amine is used as the resin used for the neon cut layer, the durability of the diimonium salt dye at the interface between the neon cut layer and the near infrared absorbing layer containing the diimmonium salt dye is used. May worsen sex.

  As the resin used for the neon cut layer not containing a diimmonium salt dye, polyester-based, acrylic-based, polyamide-based, polyurethane-based, polyolefin-based, and polycarbonate-based resins can be suitably used. Among these resins, an acrylic resin that is excellent in transparency and heat resistance when the pigment is mixed is preferable. Moreover, when bonding with an antireflection film, glass, and an electromagnetic wave prevention film, you may use an adhesive as resin.

  Examples of the pressure-sensitive adhesive include known acrylic adhesives, silicone adhesives, urethane adhesives, polyvinyl butyral adhesives (PVB), ethylene-vinyl acetate adhesives (EVA), polyvinyl ethers, saturated amorphous polyesters, A melamine resin etc. are mentioned. Among these pressure-sensitive adhesives, acrylic pressure-sensitive adhesives are preferable from the viewpoint of transparency.

  The acrylic pressure-sensitive adhesive is made of, for example, a resin mainly composed of acrylic acid ester or methacrylic acid ester. In addition, the pressure-sensitive adhesive can be used as a curing agent, for example, by mixing one or more metal chelate-based, isocyanate-based, and epoxy-based crosslinking agents together with the above-mentioned pressure-sensitive resin.

  The amount of the near-infrared absorbing dye in the wavelength selective absorption layer is preferably 1% by mass or more and 10% by mass or less based on the resin. When the amount of the near-infrared absorbing dye in the resin is small, it is necessary to increase the coating amount of the wavelength selective absorption layer in order to achieve the target near-infrared absorbing ability, and in accordance with this, sufficient drying is performed. Requires a high temperature and / or a long time, and is liable to cause deterioration of the pigment or poor flatness of the substrate. On the contrary, when the amount of the near-infrared absorbing dye in the resin is large, the interaction between the dyes becomes strong, and even if the residual solvent is reduced, the dye is likely to be denatured over time.

  In the present invention, the wavelength selective absorption layer having a single layer structure comprises a coating solution A containing an organic solvent, a resin, an aromatic diimmonium dye (a), a porphyrin dye or an azaporphyrin dye (b). It is formed by applying and drying on a transparent substrate. A wavelength selective absorption layer having a multilayer structure is formed by coating and drying a coating liquid B containing an organic solvent, a resin, and an aromatic diimmonium dye (a) on a transparent substrate. A coating liquid C containing an organic solvent and a resin and a porphyrin-based dye or an azaporphyrin-based dye (b) was applied and dried immediately above the near-infrared absorbing layer and the near-infrared absorbing layer. Includes a neon cut layer.

  At this time, it is preferable to contain a surfactant in the coating solution A or B. The coating liquid C can also contain a surfactant. However, when a pressure-sensitive adhesive is used as the resin, the surfactant need not be contained.

  By including a surfactant in the coating solution used for forming the wavelength selective absorption layer, the coating appearance of the wavelength selective absorption layer, in particular, dents from adhesion of foreign matter, etc. due to minute bubbles, dents, repelling in the drying process Improved. Furthermore, the surfactant in the wavelength selective absorption layer (coating layer) bleeds to the surface by heat treatment during drying of the coating layer. As a result, slipperiness can be imparted to the surface of the coating layer. In addition, the handling property is improved and the film can be easily wound into a roll shape even if the surface of the wavelength selective absorption layer and / or the opposite surface is made to contain particles that cause deterioration of transparency and the surface unevenness is not formed.

  In the present invention, it is important that the HLB of the surfactant is 2 or more and 12 or less. The lower limit value of HLB is preferably 3, particularly preferably 4. On the other hand, the upper limit value of HLB is preferably 11, particularly preferably 10. When the HLB is low, the leveling property is insufficient due to insufficient surface activity. On the other hand, when the HLB is high, not only the slipping property is insufficient, but also the wavelength selective absorption layer easily absorbs moisture, and the time stability of the diimmonium dye becomes poor.

  The HLB is a W.A. of Atlas Powder, Inc. of the United States. C. Griffin named Hydrophile Lyophile Balance and indexed the balance of hydrophilic groups and lipophilic groups contained in the surfactant molecules as characteristic values. The lower the value, the more hydrophilic the higher the hydrophilicity. Get higher.

  It is important that the content of the surfactant is 0.01% by mass or more and 2% by mass or less with respect to the resin constituting the wavelength selective absorption layer. When the surfactant content is low, the effect of improving the coating appearance and imparting slipperiness is insufficient. Conversely, when the surfactant content is high, the wavelength-selective absorption layer tends to absorb moisture, resulting in deterioration of the dye. Promoted.

  As the surfactant, a known cationic, anionic, or nonionic surfactant can be suitably used, but a nonionic surfactant that does not have a polar group is preferred in view of problems such as deterioration with a near-infrared absorbing dye. A silicone-based or fluorine-based surfactant having excellent surface activity is preferable.

  Silicone surfactants include dimethyl silicone, amino silane, acrylic silane, vinyl benzyl silane, vinyl benzyl amino silane, glycid silane, mercapto silane, dimethyl silane, polydimethyl siloxane, polyalkoxy siloxane, hydrodiene modified siloxane, vinyl modified siloxane, hydroxy Examples include modified siloxane, amino-modified siloxane, carboxyl-modified siloxane, halogenated-modified siloxane, epoxy-modified siloxane, methacryloxy-modified siloxane, mercapto-modified siloxane, fluorine-modified siloxane, alkyl group-modified siloxane, phenyl-modified siloxane, and alkylene oxide-modified siloxane.

  Fluorosurfactants include ethylene tetrafluoride, perfluoroalkyl ammonium salt, perfluoroalkyl sulfonic acid amide, sodium perfluoroalkyl sulfonate, perfluoroalkyl potassium salt, perfluoroalkyl carboxylate, perfluoroalkyl sulfone. Acid salts, perfluoroalkyl ethylene oxide adducts, perfluoroalkyl trimethyl ammonium salts, perfluoroalkyl amino sulfonates, perfluoroalkyl phosphate esters, perfluoroalkyl alkyl compounds, perfluoroalkyl alkyl betaines, perfluoroalkyl halides, etc. Is mentioned.

  In the present invention, the wavelength selective absorption layer is laminated by applying and drying a coating liquid containing a resin, a near-infrared absorbing dye, and a surfactant on a transparent substrate. From the viewpoint, it is necessary to dilute with an organic solvent.

  Examples of the organic solvent include (1) alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, tridecyl alcohol, cyclohexyl alcohol, 2-methylcyclohexyl alcohol, and (2) ethylene glycol. , Glycols such as diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, glycerin, (3) ethylene glycol monomethyl ether, ethylene glycol monoethylene ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether , Diethylene glycol butyl ether, ethylene glycol monomethyl Glycol ethers such as ether acetate, ethylene glycol monoethyl acetate, ethylene glycol monobutyl acetate, diethylene glycol monomethyl acetate, diethylene glycol monoethyl acetate, diethylene glycol monobutyl acetate, (4) ethyl acetate, isopropylene acetate, n-butyl acetate, etc. Examples include esters, (5) ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, isophorone, diacetone alcohol, etc. These may be used alone or in combination of two or more. Can do.

  Preferably, ketones having excellent dye solubility are contained in an amount of 30% by mass to 80% by mass with respect to the total organic solvent used in the coating solution, and other organic solvents are considered in view of leveling properties and drying properties. It is preferable to select. The boiling point of the organic solvent is preferably 60 ° C. or higher and 180 ° C. or lower. When the boiling point is low, the solid content concentration of the coating solution changes during coating, and the coating thickness is difficult to stabilize. On the other hand, when the boiling point is high, the amount of the organic solvent remaining in the coating film increases and the temporal stability becomes poor.

  Examples of the method for dissolving or dispersing the near-infrared absorbing dye and the resin in an organic solvent include stirring, dispersion and pulverization methods under heating. By heating, the solubility of the pigment and the resin can be improved, and a defect in the coating appearance due to undissolved substances or the like is prevented. Moreover, it becomes possible to form a layer having excellent transparency by dispersing and pulverizing the resin and the pigment in the coating liquid in a fine particle state of 0.3 μm or less. As the disperser and pulverizer, known ones can be used. Specifically, a ball mill, a sand mill, an attritor, a roll mill, an agitator, a colloid mill, an ultrasonic homogenizer, a homomixer, a pearl mill, a wet jet mill, a paint Examples include a shaker, a butterfly mixer, a planetary mixer, a Henschel mixer, and the like.

  When contamination or undissolved material of 1 μm or more is present in the coating solution, the appearance after coating becomes poor. Therefore, it is necessary to remove it with a filter or the like before coating. Various filters can be suitably used as the filter, but it is preferable to use a filter that removes 99% or more of a 1 μm size filter. When a coating solution containing 1 μm or more of contamination or undissolved material is applied and dried, a dent or the like is generated around the coating liquid, which may be a defect of a size of 100 μm or more and 1000 μm or less.

  It is preferable that solid content concentration, such as resin and a pigment | dye contained in a coating liquid, shall be 10 to 30 weight%. When the solid content concentration is low, it takes time to dry after coating, resulting in poor productivity and an increase in the amount of solvent remaining in the coating film, resulting in poor temporal stability. On the other hand, when the solid content concentration is high, the viscosity of the coating solution becomes high and the leveling property is insufficient, resulting in a poor coating appearance. Adjusting the viscosity of the coating solution to 10 cps or more and 300 cps or less is preferable in terms of coating appearance, and it is preferable to adjust the solid content concentration, the organic solvent, and the like so as to be in this range.

  In the present invention, as a method for coating the wavelength selective absorption layer on the transparent substrate, gravure coating method, kiss coating method, dip method, spray coating method, curtain coating method, air knife coating method, blade coating method, reverse roll coating method Ordinarily used methods such as a bar coating method and a lip coating method can be applied. Among these, a gravure coating method that can be applied uniformly, particularly a reverse gravure method is preferable. The diameter of the gravure is preferably 80 mm or less. When the diameter is large, the frequency of occurrence of ridges in the flow direction increases.

The coating amount of the wavelength selective absorption layer after drying is not particularly limited, but the lower limit is preferably 1 g / m ² , more preferably 3 g / m ² , and the upper limit is preferably 50 g / m ² , more preferably 30 g / m. ² . When the coating amount after drying is small, the near-infrared absorbing power tends to be insufficient. For this reason, when the amount of the near-infrared absorbing dye in the resin is increased, the amount of the dye present at the interface between the surface and the anchor layer is increased, and the resin is easily influenced by the outside air and the resin of the anchor layer. As a result, the deterioration of the dye is likely to occur, and the temporal stability becomes poor. Conversely, when the coating amount after drying is large, the near-infrared absorbing ability is sufficient, but the transparency in the visible light region is lowered, and the brightness of the display is lowered. Therefore, if the amount of the near-infrared absorbing dye in the resin is reduced, the optical characteristics can be adjusted, but drying tends to be insufficient. As a result, the temporal stability of the dye becomes poor due to the residual solvent in the coating film. On the other hand, when the drying is sufficient, the flatness of the substrate becomes poor.

  As a method for applying the coating liquid on the transparent substrate and drying, known hot air drying, an infrared heater, and the like can be mentioned. Hot air drying with a high drying speed is preferable.

  In the initial constant rate drying stage after coating, it is preferably dried at 20 ° C. or more and 80 ° C. or less using hot air of 2 m / sec to 30 m / sec. When the initial drying is performed strongly (the hot air temperature is high and the hot air volume is large), minute defects of the coating such as fine coating removal from foam, fine repellency, and cracks tend to occur. Conversely, when the initial drying is weakened (the hot air temperature is low and the hot air volume is small), the appearance is good, but the drying time is long and there is a problem in terms of cost. When a surfactant is not added to the coating solution, the above minute defects are likely to occur, and the initial drying needs to be considerably weakened.

  In the reduction drying process, it is necessary to make the temperature higher than the initial drying and to reduce the solvent in the coating film. Particularly preferably, the lower limit is 140 ° C and the upper limit is 170 ° C. When the temperature is low, the solvent in the coating film is difficult to decrease and becomes a residual solvent, resulting in insufficient stability of the dye over time. On the other hand, when the temperature is high, not only the flatness of the base material becomes poor due to heat wrinkles, but also the near-infrared absorbing dye is deteriorated by heat. The passing time is preferably 5 seconds or more and 180 seconds or less. If the time is short, the amount of solvent remaining in the coating film will increase, resulting in poor stability over time. Conversely, if the time is long, not only will the productivity be poor, but heat wrinkles will occur on the substrate. Therefore, the flatness becomes poor. The upper limit of the passage time is particularly preferably 30 seconds from the viewpoint of productivity and flatness.

  In the final stage of drying, it is preferable that the hot air temperature is lower than the glass transition temperature of the resin, and the actual temperature of the substrate is lower than the glass transition temperature of the resin in a flat state. When leaving the drying furnace at a high temperature, when the coated surface comes into contact with the roll surface, slippage is poor, and not only scratches but also curls may occur.

(Wavelength selective absorption filter)
In the present invention, the wavelength selective absorption filter is an optical filter having maximum absorption at wavelengths of 800 to 1200 nm and wavelengths of 550 to 620 nm. The wavelength selective absorption filter is preferably as low as possible in the near infrared region having a wavelength of 800 nm to 1200 nm. Specifically, the transmittance in the near infrared region is preferably 20% or less, and particularly preferably 10% or less. When the transmittance is high, absorption of near infrared rays emitted from the plasma display is insufficient, and malfunction of electronic equipment using the near infrared remote controller cannot be prevented.

  Further, it is preferable that the average transmittance in the visible region is higher than the average transmittance in the near-infrared region, and has sharp absorption at a wavelength of 550 nm to 620 nm, and further at a wavelength of 570 nm to 600 nm. Specifically, the transmittance at the maximum absorption wavelength within the above wavelength range is preferably 40% or less, particularly preferably 30% or less. When the transmittance in this region is high, it becomes difficult to obtain the effect of absorbing the neon light emitted from the plasma display and improving the red color. In addition, when the absorption in this region is wide, the overall transmittance of the visible light region is lowered, so that the brightness of the display tends to be lowered. The transmittance in the visible light region excluding the wavelength of 550 nm to 620 nm is preferably as high as possible, preferably 50% or more, particularly preferably 60% or more. When the transmittance is low, the color of the display is hindered and the image has a low luminance.

  The adjustment of the transmittance can be changed depending on the coating amount of the wavelength selective absorption layer and the abundance of the near infrared absorbing dye per unit area.

  As the color tone of the wavelength selective absorption filter, when expressed in the Lab color system, the a value is preferably -10.0 to +10.0, and the b value is preferably -10.0 to +10.0. If it is this range, even if it installs in the front surface of a plasma display, it becomes a natural color and is preferable.

  The method for adjusting the color tone can be achieved by coating the wavelength selective absorption layer, the abundance of the near-infrared absorbing dye per unit area, mixing other dyes, or optimizing drying conditions. In addition, when the adhesion layer and other optical filter colored on the front surface or back surface of the wavelength selective absorption filter mentioned later exist, it is preferable to adjust the color tone of the wavelength selective absorption filter to a natural color including that.

  As for the coating appearance of the wavelength selective absorption layer, it is necessary to avoid the disadvantage that the maximum diameter is 300 μm or more, more preferably 100 μm. The defect of 300 μm or more becomes like a bright spot when installed on the front surface of the plasma display, and the defect becomes noticeable. Also, streaks, unevenness, etc. with a thin coating layer become prominent on the front surface of the display and become a problem.

  It is preferable that the wavelength selective absorption filter does not change the transmittance of near-infrared rays and the transmittance of visible light even when left for a long period of time under high temperature and high humidity. When the temporal stability under high temperature and high humidity is poor, not only the color tone of the image on the display changes, but also the effect of the present invention for preventing malfunction of the electronic device using the near infrared remote controller may be lost.

  The stability over time is improved by mixing an aromatic diimmonium dye (a) with a bis (trifluoromethanesulfonyl) imide acid as a counter ion and a porphyrin dye or azaporphyrin dye (b). Reduce the amount of residual solvent in the wavelength selective absorption layer by adjusting the type of organic solvent used in the coating solution, the thickness of the coating layer, drying conditions, etc., or adjust the content of the dye in the resin It becomes possible to make it still better.

  Further, as described above, a near-infrared absorbing layer containing an aromatic diimmonium dye (a) having a resin and bis (trifluoromethanesulfonyl) imidic acid as a counter ion, a resin and a porphyrin dye or an azaporphyrin dye ( It is also a preferred embodiment from the viewpoint of temporal stability that a wavelength selective absorption layer having a multilayer structure in which the neon cut layer containing b) is formed in this order on a transparent substrate is used.

  Further, the amount of residual solvent in the wavelength selective absorption layer is preferably as small as possible, but is preferably 3% by mass or less. If the amount is 3% by mass or less, there is substantially no difference in stability over time. However, in order to further reduce the amount of residual solvent, for example, if drying is performed under severe conditions, problems such as poor planarity of the filter occur, and productivity such as reduced pressure drying decreases.

  In the present invention, for the purpose of blocking harmful electromagnetic waves emitted from the display, a conductive layer may be provided on the same surface as the infrared absorbing layer or on the opposite surface directly or via an adhesive. Either a metal mesh or a conductive thin film may be used for the conductive layer. When a metal mesh is used, it is necessary to have a metal mesh conductive layer having an aperture ratio of 50% or more. If the aperture ratio of the metal mesh is low, the electromagnetic shielding property is good, but there is a problem that the light transmittance is lowered. Therefore, an aperture ratio of 50% or more is necessary to obtain a good light transmittance. As the metal mesh used in the present invention, a metal foil having high electrical conductivity is subjected to etching treatment to form a mesh, a woven mesh using metal fibers, or metal on the surface of polymer fibers. You may use the fiber adhered using methods, such as plating. The metal used for the electromagnetic wave absorbing layer is not particularly limited as long as it has high electrical conductivity and good stability, but is not particularly limited, but from the viewpoint of workability, cost, etc., preferably copper, nickel, Tungsten etc. are good.

  When a conductive thin film is used, the transparent conductive layer may be any conductive film, but is preferably a metal oxide. Thereby, a higher visible light transmittance can be obtained. Further, in the present invention, when it is desired to improve the conductivity of the transparent conductive layer, it is preferably a repeating structure of three or more layers of metal oxide / metal / metal oxide. Conductivity can be obtained while maintaining a high visible light transmittance by multilayering the metal. Used in the present invention. The metal oxide may be any metal oxide as long as it has electrical conductivity and visible light transmittance. Examples include tin oxide, indium oxide, indium tin oxide, zinc oxide, titanium oxide, and bismuth oxide. The above is an example and is not particularly limited. The metal layer used in the present invention is preferably gold, silver or a compound containing them from the viewpoint of conductivity.

  Further, when the conductive layer is formed into multiple layers, for example, when the number of repeated layers is 3, the thickness of the silver layer is preferably 50 to 200 mm, more preferably 50 to 100 mm. When the film thickness is thicker than this, the light transmittance decreases, and when it is thin, the resistance value increases. The thickness of the metal oxide layer is preferably 100 to 1000 mm, more preferably 100 to 500 mm. If it is thicker than this, it will be colored to change its color tone, and if it is thin, the resistance value will increase. In addition, when three or more layers are formed, for example, when five layers are formed such as metal oxide / silver / metal oxide / silver / metal oxide, the thickness of the central metal oxide is the other metal. It is preferable that it is thicker than the thickness of the oxide layer. By doing so, the light transmittance of the entire multilayer film is improved.

  In the present invention, an antireflection layer or an anti-flicker layer may be provided directly or via an adhesive on the same surface as the wavelength selective absorption layer of the wavelength selective absorption filter or on the opposite surface. Moreover, in the wavelength selective absorption layer consisting of a plurality of layers, an adhesive resin is used for the neon cut layer, the function of the adhesive layer is given to the neon cut layer, and the glass plate may be bonded to a resin sheet, It may be attached directly to the display. Further, an adhesive layer may be formed on the surface of the single wavelength selective absorption layer.

  In the wavelength selective absorption filter of the present invention, a layer having an ultraviolet absorbing ability may be provided for the purpose of improving light resistance. In order to impart ultraviolet absorbing ability, an ultraviolet absorber may be added to any of the wavelength selective absorption layer, the transparent substrate, the pressure-sensitive adhesive layer, the antireflection layer, and the glare prevention layer. As the UV absorber, known ones such as organic UV inhibitors and inorganic UV inhibitors can be used.

  Next, examples and comparative examples of the present invention will be shown. The characteristic value measurement method and effect evaluation method used in the present invention are as follows.

<Viscosity of coating liquid>
The coating solution was adjusted to 20 ° C. and measured using a B-type viscometer (BL) manufactured by Tokyo Keiki Co., Ltd., at a rotor rotational speed of 60 rpm.

<Total light transmittance, haze>
Using a haze meter (Nippon Denshoku Industries, NDH2000), the total light transmittance and haze were measured.

<Light transmittance>
Using a spectrophotometer (manufactured by Hitachi, U-3500 type), the air in the range of 1100 nm to 200 nm was irradiated with light on the wavelength selective absorption layer side, and indoor air was measured as a reference for transmittance.

<Color tone>
Using a color difference meter (manufactured by Nippon Denshoku Industries Co., Ltd., ZE-2000), the wavelength selective absorption layer side is irradiated with light, and the a color value and b value of the Lab color system are used as standard light, C light source, 2 degrees. Measured at viewing angle.

<Stability over time>
After leaving for 48 hours in an atmosphere of temperature 80 ° C. and humidity 95%, the transmittance and color tone were measured. As the amount of change in color tone, ΔE was obtained from Equation 1 below. Note that ΔE indicates that the smaller the value, the less the change in color tone.

ΔE = √ ((a value before processing−a value after processing) ² + (b value before processing−b value after processing) ² )
... (1)

  Next, the amount of change ΔT before and after the temporal treatment of the transmittance was obtained from the following equation 2. ΔT indicates that the smaller the value, the smaller the amount of change.

Change amount (%) = (| transmittance after processing−transmittance before processing | / transmittance before processing) × 100
... (2)

<Appearance of coating film>
(1) Minute defects The filter after the formation of the wavelength selective absorption layer was placed on a white film, visually observed under a three-wavelength fluorescent lamp, and the following evaluation was performed. The micro defects were ranked according to the following criteria by measuring the number of defects having a size of 300 μm or more per 100 m ² area.
◎: Less than 1 micro defect ○: 1 or more and less than 5 △: Micro defect is 5 or more and less than 10 ×: 10 or more micro defects

(2) Coating failure For coating defects such as coating spots and streaks, place the wavelength selective absorption filter on a white film and visually observe the wavelength selective absorption layer surface under a 3-wavelength fluorescent lamp. Ranking was performed according to the criteria.
◎: Coating failure is not observed even when observing while moving the wavelength selective absorption filter ○: Slightly known coating failure is observed when observing while moving the wavelength selective absorption filter △: When observing while moving the wavelength selective absorption filter , Coating failure can be found ×: coating failure can be understood even when the wavelength selective absorption filter is stationary

<Adhesion>
The adhesion was measured by a test method in accordance with the provisions of JIS K 5400 8.5.1. Specifically, 100 grid-shaped cut scratches are attached from the side where the wavelength selective absorption layer is laminated using a cutter guide with a gap interval of 2 mm, and cellophane adhesive tape (Nichiban Co., Ltd. “No. 405”, 24 mm width) After being attached to the grid-like cut scratched surface and rubbed with an acrylic plate (“Sumipex” manufactured by Sumitomo Chemical Co., Ltd.), the situation when peeled off vertically was observed and observed.
○: No peeled-off squares Δ: Peeled-off squares exist, but peeled-off squares are less than 10 squares ×: 10 or more squares peeled

Example 1
(Preparation of base material)
A polyethylene terephthalate resin having an intrinsic viscosity of 0.62 dl / g is charged into a twin screw extruder, melt-extruded from a T-die at 290 ° C., solidified while applying electrostatic force on a cooled rotating metal roll, A stretched sheet was obtained.

Next, the unstretched sheet was heated to 90 ° C. with a roll stretching machine and longitudinally stretched by 3.5 times, and then the coating amount after drying the following coating liquid A on the longitudinally stretched film was 0.5 g / as will be m ^2, it was coated on both surfaces of the longitudinally stretched film, wind speed 10 m / sec and passed through 20 seconds under hot air at 120 ° C., to form an intermediate coating layer. Further, the film was heated by a tenter to 140 ° C. and then stretched 3.7 times, and then heat treated while relaxing 5% in the width (transverse) direction at 235 ° C., and a biaxially stretched polyethylene terephthalate film having an intermediate coating layer on both sides Got. The obtained film had a thickness of 100 μm, a total light transmittance of 90.2%, and a haze of 0.5%.

(Composition of coating liquid A for intermediate coating layer)
・ Ion-exchanged water 50.0% by mass
・ Isopropyl alcohol 28.9% by mass
・ Acrylic-melamine resin 10.0% by mass
(Nippon Carbide Industries Co., Ltd., A-08, solid content concentration: 46 mass%)
・ Polyester resin 10.0% by mass
(Toyobo, Vironal MD-1250, solid content: 30% by mass)
・ Polymethyl methacrylate cross-linked particles 1.0% by mass
(Nippon Shokubai, Eposta MA1001)
・ Silicon surfactant 0.1% by mass
(Dow Corning, Paintad 32)

(Adjustment of coating liquid B for wavelength selective absorption layer)
Toluene, methyl ethyl ketone, and a resin were mixed at the following mass ratio and stirred under heating to dissolve the resin, and then a dye and a surfactant were added and stirred for 30 minutes or more. Next, the coating solution B was prepared by removing undissolved substances with a filter having a nominal filtration accuracy of 1 μm.
・ Toluene 39.995% by mass
・ Methyl ethyl ketone 40.000% by mass
-Acrylic resin 18.7776% by mass
(Made by Mitsubishi Rayon, BR-80, Tg = 105 ° C)
・ Aromatic diimmonium pigment 0.695% by mass
(Nippon Carlit, CIR1085, counter ion: bis (trifluoromethanesulfonyl) imidic acid)
・ Phthalocyanine pigment 0.357% by mass
(Nippon Shokubai, IR-10A)
・ Azaporphyrin pigment 0.118% by mass
(Yamada Kasei TAP-2)
・ Silicone surfactant 0.059% by mass
(Dow Corning, Paintad 57, HLB = 6.7)

(Production of wavelength selective absorption filter)
The coating liquid B (solid content concentration: 20 mass%, viscosity: 40 cps) is applied to one of the intermediate coating layers, and the transmittance at 950 nm after drying is 4.3% (coating amount after drying is 8.0 g). / M ² ), using a slanted gravure with a diameter of 60 cm, and coating with reverse, 20 seconds with hot air of 5 m / second at 40 ° C., 20 seconds with hot air of 20 m / second at 150 ° C., and 90 ° C. And dried with passing through hot air of 20 m / sec for 10 seconds to obtain a wavelength selective absorption filter. The mass ratio of the aromatic diimmonium dye (a) to the azaporphyrin dye (b) in the wavelength selective absorption layer was (a) / (b) = 100/17.

The obtained wavelength selective absorption filter had strong absorption in the near infrared region, high transmittance in the visible light region, and sharp absorption near 590 nm. Furthermore, stability over time and coating appearance were also good.
Table 1 shows the types of dyes used in the wavelength selective absorption layer, and Tables 2 and 3 show the physical properties of the obtained wavelength selective absorption filter.

Example 2
A wavelength selective absorption filter was obtained in the same manner as in Example 1 except that the following coating liquid C was used. In the wavelength selective absorption layer, the mass ratio of the aromatic diimmonium dye (a) to the azaporphyrin dye (b) was (a) / (b) = 100/17.

(Adjustment of coating liquid C for wavelength selective absorption layer)
Toluene, cyclopentanone, and a resin were mixed at the following mass ratio and stirred under heating to dissolve the resin, and then a dye and a surfactant were added and stirred for 30 minutes or more. Subsequently, the undissolved material was removed with a filter having a nominal filtration accuracy of 1 μm to prepare a coating solution C.
・ Toluene 40.088 mass%
・ Cyclopentanone 40.088% by mass
-Copolyester resin having a fluorene skeleton 18.7876% by mass
(Kanebo, O-PET, Tg = 150 ° C.)
・ Aromatic diimmonium pigment 0.695% by mass
(Nippon Carlit, CIR1085, counter ion: bis (trifluoromethanesulfonyl) imidic acid)
-Phthalocyanine pigment 0.176% by mass
(Nippon Shokubai, IR-12)
・ Azaporphyrin pigment 0.118% by mass
(Yamada Kasei TAP-2)
・ Silicone surfactant 0.059% by mass
(Dow Corning, Paintad 57, HLB = 6.7)

The obtained wavelength selective absorption filter had a strong absorption in the near-infrared region, a high transmittance in the visible light region, and a sharp absorption near 590 nm, as in Example 1. Furthermore, stability over time and coating appearance were also good. However, the adhesion with the substrate was slightly poor.
Table 1 shows the types of dyes used in the wavelength selective absorption layer, and Tables 2 and 3 show the physical properties of the obtained wavelength selective absorption filter.

Comparative Example 1
A wavelength selective absorption filter was obtained in the same manner as in Example 1 except that the following coating solution D was used.
(Adjustment of coating liquid D for wavelength selective absorption layer)
Toluene, methyl ethyl ketone, and a resin were mixed at the following mass ratio and stirred under heating to dissolve the resin, and then a dye and a surfactant were added and stirred for 30 minutes or more. Subsequently, the undissolved material was removed with a filter having a nominal filtration accuracy of 1 μm to prepare a coating solution D.
・ Toluene 39.998% by mass
・ Methyl ethyl ketone 39.998 mass%
-Acrylic resin 18.825 mass%
(Made by Mitsubishi Rayon, BR-80)
・ Aromatic diimmonium pigment 0.697% by mass
(Nippon Carlit, CIR1085, counter ion: bis (trifluoromethanesulfonyl) imidic acid)
-Phthalocyanine pigment 0.358% by mass
(Nippon Shokubai, IR-10A)
・ Squarylium pigment 0.065% by mass
(Kyowa Hakko, SD184)
・ Silicone surfactant 0.059% by mass
(Dow Corning, Paintad 57, HLB = 6.7)

The obtained wavelength selective absorption filter had a strong absorption in the near-infrared region, a high transmittance in the visible light region, and a sharp absorption near 590 nm, as in Example 1. However, the temporal stability was poor.
Table 1 shows the types of dyes used in the wavelength selective absorption layer, and Tables 2 and 3 show the physical properties of the obtained wavelength selective absorption filter.

Comparative Example 2
A wavelength selective absorption filter was obtained in the same manner as in Example 1 except that the following coating solution E was used. The mass ratio of the aromatic diimmonium dye (a) to the azaporphyrin dye (b) in the wavelength selective absorption layer was (a) / (b) = 100/19.

(Adjustment of coating liquid E for wavelength selective absorption layer)
Toluene, methyl ethyl ketone, and a resin were mixed at the following mass ratio and stirred under heating to dissolve the resin, and then a dye and a surfactant were added and stirred for 30 minutes or more. Subsequently, the undissolved material was removed with a filter having a nominal filtration accuracy of 1 μm to prepare a coating solution E.
・ Toluene 40.002% by mass
・ Methyl ethyl ketone 40.002 mass%
・ Acrylic resin 18.839% by mass
(Made by Mitsubishi Rayon, BR-80)
・ Aromatic diimonium dye 0.622% by mass
(Nippon Shokubai, IRG022, counter ion: hexafluoroantimonic acid)
-Phthalocyanine pigment 0.358% by mass
(Nippon Shokubai, IR-10A)
・ Azaporphyrin pigment 0.118% by mass
(Yamada Kasei TAP-2)
・ Silicone surfactant 0.059% by mass
(Dow Corning, Paintad 57, HLB = 6.7)

The obtained wavelength selective absorption filter had a strong absorption in the near-infrared region, a high transmittance in the visible light region, and a sharp absorption near 590 nm, as in Example 1. However, the temporal stability was poor.
Table 1 shows the types of dyes used in the wavelength selective absorption layer, and Tables 2 and 3 show the physical properties of the obtained wavelength selective absorption filter.

Example 3
(Adjustment of coating solution F for near-infrared absorbing layer in wavelength selective absorbing layer)
Toluene, methyl ethyl ketone, and a resin were mixed at the following mass ratio and stirred under heating to dissolve the resin, and then a dye and a surfactant were added and stirred for 30 minutes or more. Subsequently, the undissolved material was removed with a filter having a nominal filtration accuracy of 1 μm to prepare the coating solution F.
・ Toluene 40.56 mass%
・ Methyl ethyl ketone 40.57 mass%
-Acrylic resin 18.7776% by mass
(Made by Mitsubishi Rayon, BR-80, Tg = 105 ° C)
・ Aromatic diimmonium pigment 0.695% by mass
(Nippon Carlit, CIR1085, counter ion: bis (trifluoromethanesulfonyl) imidic acid)
・ Phthalocyanine pigment 0.357% by mass
(Nippon Shokubai, IR-10A)
・ Silicone surfactant 0.059% by mass
(Dow Corning, Paintad 57, HLB = 6.7)

(Adjustment of coating liquid G for neon cut layer in wavelength selective absorption layer)
After mixing at the following mass ratio, the mixture was stirred for 30 minutes or more. Next, the undissolved material was removed with a filter having a nominal filtration accuracy of 1 μm to prepare the coating solution G.
・ Methyl ethyl ketone 49.808% by mass
・ Acrylic adhesive 49.847% by mass
(Soken Chemicals, SK Dyne 1435, solid content 30% by weight)
・ Azaporphyrin pigment 0.045% by mass
(Yamada Kasei TAP-2)
・ Curing agent 0.150% by mass
(Soken Chemical, L-45)
・ Curing agent 0.150% by mass
(TD-75, manufactured by Soken Chemical)

(Production of wavelength selective absorption filter)
On the intermediate coating layer forming surface obtained in the same manner as in Example 1, the transmittance at 950 nm after drying the coating solution F is 4.3% (the coating amount after drying is 8.0 g / m ² ). The film was applied in reverse using a diagonal gravure with a diameter of 60 cm, heated at 40 ° C. with hot air of 5 m / second for 20 seconds, 150 ° C. with hot air of 20 m / second for 20 seconds, and further heated at 90 ° C. with hot air of 20 m / second. It was allowed to pass for 10 seconds and dried to form a near-infrared absorbing layer. Next, the coating solution G is applied onto the near infrared absorbing layer using a lip coater so that the coating amount after drying is 16 g / m ² , and heated at 40 ° C. with hot air of 5 m / second for 20 seconds. A neon cut layer was formed by passing for 20 seconds at 150 ° C. with hot air of 20 m / sec for 20 seconds and further passing at 90 ° C. with hot air of 20 m / sec for 10 seconds. That is, a wavelength selective absorption filter having a wavelength selective absorption layer composed of two layers of a near infrared absorption layer and a neon cut layer was obtained. In the wavelength selective absorption layer, the mass ratio of the aromatic diimmonium dye (a) to the azaporphyrin dye (b) was (a) / (b) = 100/17.

The obtained wavelength selective absorption filter had strong absorption in the near infrared region, high transmittance in the visible light region, and sharp absorption near 590 nm. Furthermore, stability over time and coating appearance were also good.
Table 1 shows the types of dyes used in the wavelength selective absorption layer, and Tables 2 and 3 show the physical properties of the obtained wavelength selective absorption filter.

  The wavelength selective absorption filter of the present invention has a low transmittance in the near-infrared region and neon light region, a high transmittance in the visible light region, little change in optical characteristics over time, and excellent durability. It is possible to stably display an image that is good by being installed on the front side of the camera, and it is possible to prevent malfunction of precision equipment using a near-infrared remote controller, which can greatly contribute to the industry.

Claims (10)

A polyester-based film is used as a transparent substrate, and a single-layer or multiple-layer wavelength selective absorption layer containing a resin, a near-infrared absorbing dye (A), and a dye (B) is laminated on the transparent substrate, And the wavelength selective absorption filter which has maximum absorption in wavelength 800-1200nm and wavelength 550-620nm,
One of the near-infrared absorbing dyes (A) is an aromatic diimmonium dye (a) having bis (trifluoromethanesulfonyl) imidic acid as a counter ion,
One of the dyes (B) is a porphyrin dye or an azaporphyrin dye (b).   A multi-layer wavelength selective absorption layer is formed on a transparent substrate in this order, a near-infrared absorption layer containing a resin and a near-infrared absorption dye (A), and a neon cut layer containing a resin and a dye (B). The wavelength selective absorption filter according to claim 1, wherein   The wavelength selective absorption layer contains 5 to 100 parts by mass (mass ratio) of the porphyrin dye or azaporphyrin dye (b) with respect to 100 parts by mass of the aromatic diimmonium dye (a). Item 2. The wavelength selective absorption filter according to Item 1.   The wavelength selective absorption filter according to claim 1, wherein the resin constituting the wavelength selective absorption layer is an acrylic resin.   A single-layer wavelength selective absorption layer comprises a coating solution A containing an organic solvent, a resin, an aromatic diimmonium dye (a), a porphyrin dye or an azaporphyrin dye (b) on the transparent substrate. 2. The wavelength selective absorption filter according to claim 1, wherein the wavelength selective absorption filter is formed by coating and drying.   Near-infrared absorption formed by coating and drying a coating liquid B containing an organic solvent, a resin, and an aromatic diimmonium dye (a) on the transparent base material. A neon cut layer formed by coating and drying a coating liquid C containing an organic solvent and a resin and a porphyrin-based dye or azaporphyrin-based dye (b) immediately above the near-infrared absorbing layer The wavelength selective absorption filter according to claim 1.   The wavelength selective absorption filter according to claim 5 or 6, wherein the coating liquid A or B further contains a surfactant having an HLB of 2 to 12.   The wavelength selective absorption filter according to claim 7, wherein the surfactant is a silicone-based surfactant or a fluorine-based surfactant. The wavelength selective absorption filter according to any one of claims 1 to 8, further comprising an intermediate layer containing particles between the transparent substrate and the wavelength selective absorption layer. The wavelength selective absorption filter according to claim 9, wherein the particles are selected from silica, kaolinite, talc, calcium carbonate, zeolite, alumina, acrylic, PMMA, nylon, styrene, polyester, and benzoguanamine / formalin condensate. .