optical filter

Abstract

The present application discloses a kind of optical filter, including substrate layer and near infrared absorption layer on the substrate layer, wherein the near infrared absorption layer includes: copper complex, which is formed by copper compound for providing copper ion, phosphonic acid shown in formula 1 and at least one phosphorus-containing compound shown in formula 2 to formula 4, wherein the OD value of the optical filter to 930nm-950nm incident light wavelength is greater than 4.The present application can efficiently absorb near infrared by setting specific near infrared absorption layer in optical filter, and has excellent visible light transmittance, and can reduce the burden of subsequent processing.

Description

TECHNICAL FIELD

[0001] The present application relates to a filter, in particular to a filter comprising a near-infrared absorbing layer, the near-infrared absorbing layer comprising a copper complex. BACKGROUND

[0002] The near-infrared absorbing filter is widely used in optical devices, such as image sensors. As the market demands for imaging accuracy and pattern optical quality are increasing, the current near-infrared absorbing filter cannot meet the new requirements. Therefore, it is necessary to develop a near-infrared absorbing filter with good transmittance in the visible light region and good shielding property (i.e. low transmittance, lower than the current 8-15% transmittance) in the near-infrared region to meet the stringent requirements of the current standards.

[0003] On the other hand, the optical recognition elements currently widely used usually use near-infrared light as the recognition light source, especially near-infrared light with a wavelength of 940 nm. Therefore, in devices that integrate optical recognition elements and image sensors, the filter of the image sensor must effectively block the recognition light source.

[0004] The filtering effect of the absorbing filter is related to the thickness of the material. The thinner the material, the better the light transmittance. The thicker the material, the more significant the filtering effect. The known technology has reported technical means for improving the filtering effect by increasing the thickness of materials with near-infrared cutoff function, such as blue glass, absorbing dye layer, or increasing the number and thickness of optical coatings, such as anti-reflection film. However, as the market increasingly emphasizes portability (e.g. light, thin, short, small), technical means for improving optical performance by increasing the thickness of materials or coatings no longer meet market demand.

[0005] In addition, although the filtering effect can be enhanced by increasing the thickness of the coating, the material processing and the difficulty of the process will deteriorate with the increase of the thickness and complexity of the coating, and the loss rate will also increase, which will increase the cost and lead to a decrease in industrial applicability. The increase in the thickness of the coating also causes the deterioration of image quality, which does not meet the current market trend of pursuing high definition. SUMMARY

[0006] To solve the above problems, the present application provides a filter, which comprises:

[0007] a substrate layer; and

[0008] a near-infrared absorbing layer on the substrate layer, wherein the near-infrared absorbing layer comprises:

[0009] a copper complex formed by a copper compound for providing copper ions, a phosphonic acid represented by Formula 1, and at least one phosphorus-containing compound represented by Formulae 2-4,

[0010]

[0011] wherein R, R1, R2, R3 are each independently a substituted or unsubstituted C1 to C 12 alkyl group or a substituted or unsubstituted C6 to C 12 aryl group,

[0012] wherein the optical filter has an OD value of greater than 4 for a 930 nm to 950 nm incident light wavelength.

[0013] In one embodiment, the substituted or unsubstituted C1 to C 12 alkyl group is selected from the group consisting of a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a sec-butyl group, an i-butyl group, a t-butyl group; and the substituted or unsubstituted C6 to C 12 aryl group is selected from the group consisting of a phenyl group, a naphthyl group, a chlorophenyl group.

[0014] In one embodiment, the near-infrared absorbing layer has a haze of 0.4% or less.

[0015] In one embodiment, the near-infrared absorbing layer has at least one main peak in an X-ray photoelectron spectrum at a binding energy of 930 electron volts (eV) to 940 electron volts (eV). In another embodiment, the at least one main peak in the X-ray photoelectron spectrum has a counts per second value of 4500 or more.

[0016] In one embodiment, the near-infrared absorbing layer has a thickness of 25 μm to 150 μm.

[0017] In one embodiment, the optical filter has an OD value of greater than 4.5 for a 940 nm incident light wavelength.

[0018] In one embodiment, the near-infrared absorbing layer further includes an optical resin in which the copper complex is dispersed. In one embodiment, the optical resin is a thermoplastic resin and / or a photo-curable resin. In one embodiment, the optical resin is selected from the group consisting of polycarbonate-based, polyester-based, polycycloolefin-based, polyacrylic-based, silicone-based, and polyimide-based.

[0019] In one embodiment, the optical filter further includes a filter layer on the other side of the base layer relative to the near-infrared absorbing layer.

[0020] In one embodiment, the optical filter further includes a filter layer on the other side of the base layer relative to the near-infrared absorbing layer.

[0021] In one embodiment, the light filter layer includes a first absorbing dye layer and a second absorbing dye layer, the first absorbing dye layer includes a near-infrared absorbing dye, and the second absorbing dye layer includes an ultraviolet absorbing dye.

[0022] In one embodiment, the near-infrared absorbing dye is at least one selected from the group consisting of azo-based compounds, diimmonium-based compounds, dithiol metal complexes, squaraine-based compounds, cyanine-based compounds, and phthalocyanine-based compounds.

[0023] In one embodiment, the ultraviolet absorbing dye is at least one selected from the group consisting of azomethine-based compounds, indole-based compounds, ketone-based compounds, benzimidazole-based compounds, and triazine-based compounds.

[0024] In one embodiment, the first absorbing dye layer and the second absorbing dye layer each have a thickness of 0.5 μm to 10 μm, and the total thickness of the light filter layer is 0.5 μm to 10 μm.

[0025] In one embodiment, the light filter further includes at least one anti-reflection layer positioned at the outermost side of the light filter.

[0026] In one embodiment, the material of the at least one anti-reflection layer is at least one selected from TiO2, SiO2, Y2O3, MgF2, Al2O3, Nb2O5, AlF3, Bi2O3, Gd2O3, LaF3, PbTe, Sb2O3, SiO, SiN, Ta2Os, ZnS, ZnSe, ZrO2, and Na3AlF6, and has a thickness of 0.5 μm to 10 μm.

[0027] In one embodiment, the light filter further includes a protective layer, and the material of the protective layer is an optical resin.

[0028] In one embodiment, the protective layer has a thickness of 10 μm to 30 μm, and is positioned between the near-infrared absorbing layer and the anti-reflection layer.

[0029] In one embodiment, the total thickness of the light filter is 225 μm to 800 μm.

[0030] In one embodiment, the light filter has a passband overlapping a wavelength range of 350 nm to 850 nm, and the center wavelength of the passband is positioned within the wavelength range of 350 nm to 850 nm.

[0031] In one embodiment, the light filter has a haze of 0.5% or less.

[0032] In an embodiment, the maximum transmittance of the optical filter to the wavelength range of 930 nm to 950 nm incident light is 0.01% or less; the maximum transmittance of the optical filter to the wavelength range of 930 nm to 950 nm incident light is 0.005% or less; the minimum transmittance of the optical filter to the wavelength range of 460 nm to 560 nm incident light is 80% or more; the minimum transmittance of the optical filter to the wavelength range of 460 nm to 560 nm incident light is 85% or more.

[0033] In an embodiment, when the incident light irradiates the optical filter at the incident angles of 0 degree and 30 degrees respectively, there is a shift in the center wavelength of the passband of the optical filter, and the shift amplitude is 1.4 nm or less; when the incident light irradiates the optical filter at the incident angles of 0 degree and 35 degrees respectively, there is a shift in the center wavelength of the passband of the optical filter, and the shift amplitude is 1.9 nm or less.

[0034] The optical filter of the present application can efficiently absorb the incident light with a wavelength of 800 nm to 1100 nm, more particularly, excellently absorb the incident light with a wavelength of 940 nm, while having a high transmittance to visible light, by disposing a specific near-infrared absorbing layer therein. Therefore, the present application achieves excellent near-infrared cutoff effect and maintains high transmittance to visible light without increasing the product thickness, the coating thickness, and the complexity. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figures 1A to 1C 、 Figures 2 to 4 is a schematic structural diagram of the optical filter of the present application;

[0036] Figure 5 is an X-ray photoelectron spectrum of the near-infrared absorbing layer in Preparation Example 1;

[0037] Figure 6 is a transmittance curve diagram of the first filter layer and the second filter layer in Preparation Example 1;

[0038] Figure 7 is a transmittance curve diagram of the AF32 glass and the transmittance curve diagram of the filter layer and the near-infrared absorbing layer in Preparation Example 1;

[0039] Figure 8 is a transmittance curve diagram of the three embodiments of the substrate layer, the substrate layer + filter layer, and the substrate layer + near-infrared absorbing layer + filter layer in Preparation Example 1;

[0040] Figure 9 is a transmittance curve diagram of the optical filter of Example 1 and Comparative Example 1;

[0041] Figure 10 is a transmittance curve diagram of the optical filter of Example 2 and Comparative Example 1;

[0042] Figure 11Transmittance curve of the filter of Example 3 and Comparative Example 1;

[0043] Figure 12 Transmittance curve of the filter of Example 4 and Comparative Example 1;

[0044] Figure 13 OD value curve of the filters of Examples 1 to 4 against 930 to 950 nm incident light wavelength;

[0045] Figure 14 Transmittance curve of the filter of Example 1 irradiated at 0, 30, and 35 degrees of incident angle, respectively;

[0046] Figure 15 Transmittance curve of the filter of Example 3 irradiated at 0, 30, and 35 degrees of incident angle, respectively;

[0047] Explanation of main component symbols

[0048] 1, 1', 1", 1"' - filter;

[0049] 10 - near infrared absorbing layer;

[0050] 11 - adhesive layer;

[0051] 12 - protective layer;

[0052] 20 - base layer;

[0053] 30 - filter layer;

[0054] 31 - first absorbing dye layer;

[0055] 32 - second absorbing dye layer;

[0056] 40 - anti-reflection layer. DETAILED DESCRIPTION

[0057] The scope and effects of the present application can be easily understood by those skilled in the art from the following specific examples.

[0058] It is to be understood that the structures, proportions, sizes, etc. shown in the drawings accompanying the present specification are merely intended to assist in the understanding of the present description and are not intended to limit the scope of the present application, and thus, any modification, change in proportion, or adjustment in size, which does not affect the effects that can be achieved by the present application, should still fall within the scope of the present application. Also, the terms such as "upper", "first", "second", etc. used in the present specification are merely intended to facilitate clear description and are not intended to limit the scope of the present application, and thus, any change in relative relationship or adjustment without substantial change in technical content should be considered as within the scope of the present application.

[0059] When "comprise", "include" or "have" a certain element in the present description, unless otherwise stated, other elements, components, structures, regions, parts, devices, systems, steps or connection relationships, etc. can also be included, but not excluding these other elements.

[0060] Unless otherwise explicitly stated herein, the singular forms "a" and "the" as used herein also include the plural forms, and "or" and "and / or" as used herein can be used interchangeably.

[0061] The numerical ranges described herein are inclusive and combinable, and any numerical value falling within the numerical ranges described herein can be used as a maximum or minimum value to derive a sub-range; for example, the numerical range "25 to 200" should be understood as including any sub-range between the endpoints 25 and 200, such as 25 to 150, 30 to 200, 30 to 150, etc. sub-ranges; in addition, if a numerical value falls within each range described herein (e.g. between the maximum and minimum values), it should be considered as included within the scope of the present application.

[0062] The present application mainly provides an optical filter. Specifically, the optical filter of the present application comprises a substrate layer and a near-infrared absorbing layer on the substrate layer.

[0063] The near-infrared absorbing layer of the present application can be prepared from a near-infrared composition. The near-infrared composition can include a copper compound, a phosphonic acid, and a phosphorus-containing compound.

[0064] The copper compound mainly serves as a source of copper ions, and a known copper compound that can provide divalent copper ions (Cu2+) can be used, such as a copper salt, which can be exemplified by copper acetate or a hydrate of copper acetate, and can also be exemplified by copper chloride, copper formate, copper stearate, copper benzoate, copper pyrophosphate, copper naphthenate, anhydride or hydrate of copper citrate. In one embodiment, the copper compound is copper acetate.

[0065] The phosphonic acid is shown in formula 1 below,

[0066]

[0067] wherein R is a substituted or unsubstituted C1to C12alkyl group or a substituted or unsubstituted C6to C12aryl group.

[0068] Alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, iso-butyl, t-butyl, pentyl, and the like, and substituted alkyl groups include, but are not limited to, haloalkyl, hydroxyalkyl, nitroalkyl, alkoxyalkyl, and the like. Aryl groups include, but are not limited to, phenyl, naphthyl, and the like, and substituted aryl groups include, but are not limited to, haloaryl (e.g., chlorophenyl), nitroaryl, hydroxyaryl, alkoxyaryl, alkylaryl, haloalkylaryl, nitroalkylaryl, hydroxyalkylaryl. In one embodiment, the phosphonic acid is butyl phosphonic acid.

[0069] The phosphorus-containing compounds are shown in Formulae 2 to 4 below,

[0070]

[0071] wherein R, R1, R2, R3are each independently a C1to C12alkyl group or a C6to C12aryl group, as defined for R in Formula 1.

[0072] The phosphorus-containing compounds can have a dispersing function to disperse components in the composition (including the formed copper complex) from each other, to achieve uniform dispersion, and one of the effects of this function is that the crystallite size in the composition can be 100 nm or less, further 5 nm to 80 nm, or 20 nm to 60 nm, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100 nm. When the crystallite size is 5 nm or more, sufficient near-infrared absorbing properties can be exhibited, and when the crystallite size is 100 nm or less, the number average particle size is small, and a product made from the near-infrared absorbing composition has low haze. In the present application, at least one phosphorus-containing compound shown in Formulae 2 to 4 is used to prepare the near-infrared absorbing composition.

[0073] The copper compound, the phosphonic acid, and the phosphorus-containing compound in the near-infrared absorbing composition can be formulated in a desired ratio. For example, in the near-infrared absorbing composition, the copper compound can be 150 parts by weight, and can be exemplified by 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, or 150 parts by weight; the phosphonic acid can be 100 parts by weight, and can be exemplified by 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 parts by weight; and the total amount of the phosphorus-containing compound can be 1 to 90 parts by weight, and can be exemplified by 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 90 parts by weight.

[0074] In an embodiment, the near-infrared absorbing composition of the present application includes the phosphorus-containing compounds represented by Formulae 2 to 4 at the same time, and the ratio can be formulated as desired. For example, in the near-infrared absorbing composition, the phosphorus-containing compound represented by Formula 2 can be 1 to 90 parts by weight, the phosphorus-containing compound represented by Formula 3 can be 1 to 90 parts by weight, and the phosphorus-containing compound represented by Formula 4 can be 1 to 90 parts by weight, wherein each of the phosphorus-containing compounds represented by Formulae 2 to 4 can be exemplified by 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 90 parts by weight. In another embodiment, the phosphorus-containing compound represented by Formula 2: the phosphorus-containing compound represented by Formula 3: the phosphorus-containing compound represented by Formula 4 is 20:20:50.

[0075] In an embodiment, the near-infrared absorbing composition of the present application can be in the form of a dispersion, i.e., further includes a solvent in addition to the copper compound, the phosphonic acid, and the phosphorus-containing compound. In formulation, the copper compound, the phosphonic acid, and the phosphorus-containing compound can be added to the solvent and mixed, and the ratio of these components to the solvent can be 1:5 to 1:1, for example, 1:3, but is not limited thereto.

[0076] The solvent can be selected from those known in the art, including but not limited to water, alcohols, ketones, ethers, esters, aromatic hydrocarbons, halogenated hydrocarbons, dimethylformamide, dimethylacetamide, dimethylsulfoxide, sulfolane, and the like. Specifically, alcohols such as methanol, ethanol, propanol, and the like. Esters such as alkyl formates, alkyl acetates, alkyl propionates, alkyl butyrates, alkyl lactates, alkyl alkoxyacetates, alkyl 3-alkoxypropionates, alkyl 2-alkoxypropionates, alkyl 2-alkoxy-2-methylpropionates, alkyl pyruvates, alkyl acetoacetates, alkyl 2-oxobutyrates, and the like. Ethers such as, for example, diethylene glycol dimethyl ether, tetrahydrofuran, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, and the like. Ketones such as, for example, methyl ethyl ketone, cyclohexanone, cyclopentanone, 2-heptanone, 3-heptanone, and the like. Aromatic hydrocarbons such as, for example, toluene, xylene, and the like.

[0077] The mixing can be, for example, sufficient agitation at room temperature (e.g., 25°C) for a period of time of, for example, 4 hours or more, 6 hours or more, 8 hours or more, but is not limited thereto.

[0078] In the near infrared absorbing composition, the components interact with and react with each other to form a copper complex, which can be represented as Cu2+X, wherein Cu2+is provided by the copper compound and X is contributed by the phosphonic acid and / or phosphorus-containing compound.

[0079] In one embodiment, the near infrared absorbing composition can further be in the form of a coating liquid. Specifically, the near infrared absorbing composition in the form of a dispersion liquid described above can be mixed with an optical resin to form a coating liquid, and the ratio of the dispersion liquid to the optical resin can be 5: 1 to 1: 1 or 3: 1 to 1: 1, for example, 0.65:0.35, but is not limited thereto. In the case of using the near infrared absorbing composition in the form of a coating liquid, it is formed on a substrate, dried and cured to form a near infrared absorbing layer.

[0080] The optical resin can be a thermoplastic resin and / or a photocurable resin. In one embodiment, the optical resin is selected from the group consisting of polycarbonates, polyesters, polycycloolefins, polyacrylics, silicone resins, and polyimides. In one embodiment, the optical resin is a silicone resin.

[0081] Further, in order to perform a curing process, a curing agent such as a photocuring agent can be further added, so that the film can be cured by light irradiation.

[0082] In one embodiment, the near-infrared absorbing layer of the present application has a haze of 0.4% or less, 0.3% or less, or 0.2% or less, for example, 0.4%, 0.35%, 0.3%, 0.25%, 0.2%, 0.19%, 0.18%, 0.17%, 0.16%, 0.15%, 0.14%, 0.13%, 0.12%, 0.11%, or 0.1%.

[0083] The thickness of the near-infrared absorbing layer also affects the characteristics of near-infrared absorption. Generally speaking, as the thickness of the near-infrared absorbing layer increases, the near-infrared cutoff ability also increases, but does not meet the demand for thinness, and as the thickness of the near-infrared absorbing layer decreases, the near-infrared cutoff ability also decreases. In one embodiment, the near-infrared absorbing layer of the present application can achieve excellent near-infrared cutoff ability in a relatively thin case, specifically, the thickness of the near-infrared absorbing layer is between 25 μm and 150 μm, between 50 μm and 150 μm, or between 100 μm and 150 μm, for example, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 125 μm, 130 μm, 135 μm, 140 μm, 145 μm, 146 μm, 147 μm, or 150 μm.

[0084] In one embodiment, the near-infrared absorbing layer of the present application has at least one main peak in the X-ray photoelectron spectrum at a binding energy of 930 electron volts to 940 electron volts. In one embodiment, the count per second value of the at least one main peak is 4500 or more, 4600 or more, 4700 or more, 4800 or more, 4900 or more, or 5000 or more.

[0085] In one embodiment, the near-infrared absorbing layer of the present application has a maximum transmittance of 0.1% or less, less than 0.1%, 0.05% or less, less than 0.05%, 0.01% or less, less than 0.01%, 0.005% or less, or less than 0.005%, for example, 0.1%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, 0.02%, 0.01%, 0.009%, 0.0008%, 0.007%, 0.0006%, 0.005%, 0.004%, 0.003%, 0.002%, or 0.001%, for the wavelength range of 930 nm to 950 nm (including for 940 nm incident light); and, on the other hand, has an OD value of 3 or more, more than 3, 3.5 or more, more than 3.5, 4 or more, more than 4, 4.5 or more, or more than 4.5, for example, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, for the wavelength range of 930 nm to 950 nm (including for 940 nm incident light). In one embodiment, the near-infrared absorbing layer of the present application has a minimum transmittance of 80% or more, or 85% or more, for example, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, or 90%, for the wavelength range of 460 nm to 560 nm.

[0086] In one embodiment, the near-infrared absorbing layer of the present application has a passband overlapping with the wavelength range of 350 nm to 850 nm, 350 nm to 800 nm, or 350 nm to 750 nm, and the center wavelength of the passband is within the wavelength range of 350 nm to 850 nm, 350 nm to 800 nm, 350 nm to 750 nm, 400 nm to 700 nm, 450 nm to 650 nm, 500 nm to 600 nm, or 500 nm to 550 nm. Herein, the "passband" refers to a section exhibiting a transmittance of 50% or more for incident light within a wavelength range, and the "center wavelength of the passband" refers to the average of the two incident light wavelengths at which a transmittance of 50% is exhibited for incident light.

[0087] In an embodiment, the substrate layer can be used to support the near-infrared absorbing layer, and also to assist the filtering effect of the near-infrared absorbing layer, so that the optical filter exhibits better optical performance, for example, further improving the cutoff effect of near-infrared and / or ultraviolet. The substrate layer can be glass, for example, transparent glass (such as AF32 glass) or blue glass, wherein when blue glass is selected, the substrate layer can exhibit a cutoff effect for near-infrared. The blue glass is, for example, phosphate glass, for example, blue glass formed from materials such as metaphosphate compounds, carbonate compounds, metal oxides, and metal fluorides, wherein the metaphosphate compounds include but are not limited to aluminum metaphosphate, magnesium metaphosphate, lithium metaphosphate, zinc metaphosphate, and calcium metaphosphate, the carbonate compounds include but are not limited to calcium carbonate, barium carbonate, and strontium carbonate, the metal oxides include but are not limited to copper oxide, aluminum oxide, zinc oxide, and magnesium oxide, and the metal fluorides include but are not limited to aluminum fluoride, magnesium fluoride, calcium fluoride, strontium fluoride, barium fluoride, and zinc fluoride. The glass raw materials can be uniformly mixed and then placed in a crucible, and the crucible is then placed in an atmospheric or reducing atmosphere furnace, and the temperature is controlled between 700°C and 1000°C to obtain a homogenized glass.

[0088] In an embodiment, the substrate layer is blue glass, wherein the molar ratio of phosphorus / (aluminum + lanthanum + niobium + yttrium) can be 1.5 to 16, and the molar ratio of fluorine / (fluorine + oxygen) can be 0.01 to 0.2. In an embodiment, the blue glass contains 35 to 55 mol% of phosphorus, 3.5 to 15 mol% of aluminum, 15 to 25 mol% of alkali metal, 10 to 35 mol% of alkaline earth metal and divalent metal, 10 to 21 mol% of copper, and a total of 0 to 7 mol% of lanthanum + niobium + yttrium, and wherein the molar ratio of copper / phosphorus is 0.25 to 0.7, and the molar ratio of fluorine / (fluorine + oxygen) is 0.01 to 0.2.

[0089] In an embodiment, the thickness of the substrate layer is between 200 μm and 500 μm, between 200 μm and 400 μm, or between 200 μm and 300 μm, for example, 200 μm, 225 μm, 250 μm, 275 μm, 300 μm, 325 μm, 350 μm, 375 μm, 400 μm, 425 μm, 450 μm, 475 μm, or 500 μm.

[0090] The arrangement of the layers in the optical filter of the present application is not limited, for example, as shown in FIG. 1, the optical filter 1 includes a near-infrared absorbing layer 10 and a substrate layer 20, wherein the near-infrared absorbing layer 10 is located on the substrate layer 20. Figure 1A

[0091] In an embodiment, the optical filter of the present application further includes a filter layer. In an embodiment, the position of the filter layer in the optical filter is not limited, for example, as shown in FIG. 2, the optical filter 1 includes a near-infrared absorbing layer 10, a substrate layer 20, and a filter layer 30, wherein the near-infrared absorbing layer 10 is located on the substrate layer 20, and the filter layer 30 is located on the near-infrared absorbing layer 10. Figure 1A ​As shown, the filter layer 30 is located on the other side of the base layer 20 relative to the near-infrared absorbing layer 10, i.e., the near-infrared absorbing layer 10 and the filter layer 30 are located on the two sides of the base layer 20, respectively. In other embodiments, the filter layer 30 can also be located on the same side of the base layer 20 as the near-infrared absorbing layer 10, i.e., the near-infrared absorbing layer 10 and the filter layer 30 are located on the same side of the base layer 20. Figure 3 As shown, the filter layer 30 in the filter 1" is located between the near-infrared absorbing layer 10 and the base layer 20; the filter layer 30 can also be located on the same side of the base layer 20 as the near-infrared absorbing layer 10, i.e., the near-infrared absorbing layer 10 and the filter layer 30 are located on the same side of the base layer 20. Figure 4 As shown, the near-infrared absorbing layer 10 in the filter 1"' is located between the filter layer 30 and the base layer 20.

[0092] The filter layer is used to assist the near-infrared absorbing layer to exhibit more excellent optical performance, for example, to further improve the cutoff effect on near-infrared and / or ultraviolet. In an embodiment, the filter layer can include a first absorbing dye layer and a second absorbing dye layer, and each of them includes a near-infrared absorbing dye and an ultraviolet absorbing dye. As shown in Figure 1B and 1C As shown, the filter layer 30 in the filter 1 is a double-layer structure of the first absorbing dye layer 31 and the second absorbing dye layer 32, and Figure 1B and 1C The difference between them is only the arrangement order of the first absorbing dye layer 31 and the second absorbing dye layer 32.

[0093] The filter layer can include a transparent resin material, including but not limited to, which can be selected from epoxy resin, polyurethane, polyacrylate, polyolefin, polycarbonate, polycycloolefin, and polyvinyl butyral, and the resin material can be used as the base of the filter layer coating liquid.

[0094] The near-infrared absorbing dye, such as azo-based compounds, diimmonium-based compounds, dithiol metal complexes, squaraine-based compounds, cyanine-based compounds, and phthalocyanine-based compounds, can adjust the maximum absorption wavelength to be between 650-1100 nm, or more specifically between 650-750 nm. The ultraviolet absorbing dye, such as azomethine-based compounds, indole-based compounds, ketone-based compounds, benzimidazole-based compounds, and triazine-based compounds.

[0095] In an embodiment, the thickness of the filter layer is 0.5-10 μm, for example, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm. In the case of the filter layer being a multi-layer structure, such as a double-layer structure of the first absorbing dye layer and the second absorbing dye layer, the thickness of each layer is 0.5-10 μm, for example, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, or 10 μm.

[0096] In one embodiment, the filter of the present invention further includes at least one anti-reflection layer located on the outermost side of the filter. For example... Figure 2 As shown, the anti-reflective layer 40 is located on the outermost two sides of the filter 1'.

[0097] In one embodiment, the antireflective layer is a coating formed from at least one material selected from TiO2, SiO2, Y2O3, MgF2, Al2O3, Nb2O5, AlF3, Bi2O3, Gd2O3, LaF3, PbTe, Sb2O3, SiO, SiN, Ta2Os, ZnS, ZnSe, ZrO2, and Na3AlF6. In another embodiment, the antireflective layer is formed by alternating layers of TiO2 and SiO2.

[0098] In one embodiment, the thickness of the antireflective layer is from 0.5 μm to 10 μm, for example, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm.

[0099] In one embodiment, the filter of the present invention further includes a protective layer, and the material of the protective layer is an optical resin. The optical resin referred to herein may be the optical resin used in the near-infrared absorbing composition formed in the form of a coating liquid described above.

[0100] In one embodiment, the thickness of the protective layer is from 10 μm to 30 μm, for example, 10 μm, 15 μm, 20 μm, 25 μm, or 30 μm. In one embodiment, the protective layer is located on top of the near-infrared absorbing layer, or between the near-infrared absorbing layer and a layer covering it. Figure 2 As shown, the protective layer 12 is located between the near-infrared absorption layer 10 and the anti-reflection layer 40. The protective layer is used to protect the near-infrared absorption layer. Since the near-infrared absorption layer is relatively soft, subsequent processing directly on it can easily cause scratches on the surface of the near-infrared absorption layer or even cause the near-infrared absorption layer to fall off. Therefore, a protective layer can be formed on it first to prevent damage.

[0101] In one embodiment, the filter of the present invention further includes an adhesive layer located between the near-infrared absorption film and the substrate layer. Figure 2 As shown, the adhesive layer 11 is located between the near-infrared absorbing layer 10 and the substrate layer 20. The adhesive layer can use materials known in the art for bonding adjacent layers; for example, hexamethyldisilazane (HMDS) can be used. The adhesive layer is used to prevent the near-infrared absorbing layer from detaching from the substrate layer under certain conditions, thereby improving the stability of the filter.

[0102] In one embodiment, the filter of the present invention includes: a substrate layer, a near-infrared absorption layer, a filter layer, an adhesive layer, a protective layer, and an anti-reflection layer. For example... Figure 2As shown, the filter 1' of the present application includes a substrate layer 20; a near-infrared absorbing layer 10 on one side of the substrate layer 20; an adhesive layer 11 between the substrate layer 20 and the near-infrared absorbing layer; a filter layer 30 on the other side of the substrate layer 20; a protective layer 12 on the near-infrared absorbing layer 10; and an anti-reflective layer 40 on the outermost two sides of the filter.

[0103] In one embodiment, the total thickness of the filter of the present application is about 225 μm to about 800 μm, about 250 μm to about 500 μm, or about 300 μm to about 500 μm, such as about 225 μm, about 250 μm, about 275 μm, about 300 μm, about 325 μm, about 350 μm, about 375 μm, about 400 μm, about 425 μm, about 450 μm, about 475 μm, about 500 μm, about 550 μm, about 600 μm, about 650 μm, about 700 μm, about 750 μm, or about 800 μm.

[0104] In one embodiment, the filter of the present application has a haze of 0.5% or less, 0.4%, or 0.3% or less, such as 0.5%, 0.45%, 0.4%, 0.35%, 0.3%, 0.25%, 0.2%, 0.19%, 0.18%, 0.17%, 0.16%, 0.15%, 0.14%, 0.13%, 0.12%, 0.11%, or 0.1%.

[0105] In one embodiment, the filter of the present application has a maximum transmittance of 0.01% or less, less than 0.01%, 0.005% or less, or less than 0.005% for a wavelength range of 930 nm to 950 nm incident light (including 940 nm incident light), such as 0.01%, 0.009%, 0.008%, 0.007%, 0.006%, 0.005%, 0.004%, 0.003%, 0.002%, 0.001%; on the other hand, has an OD value of 4 or more, more than 4, 4.5 or more, more than 4.5, 4.8 or more, or more than 4.8 for a wavelength range of 930 nm to 950 nm incident light (including 940 nm incident light), such as 4, 4.01, 4.1, 4.2, 4.3, 4.4, 4.5, 4.51, 4.6, 4.7, 4.8, 4.81, 4.9. In one embodiment, the filter of the present application has a minimum transmittance of 80% or more, or 85% or more for a wavelength range of 460 nm to 560 nm incident light, such as 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%.

[0106] In one embodiment, the filter of the present application has a passband overlapping the wavelength range of 350 nm to 850 nm, 350 nm to 800 nm, or 350 nm to 750 nm, and the center wavelength of the passband is within the wavelength range of 350 nm to 850 nm, 350 nm to 800 nm, 350 nm to 750 nm, 400 nm to 700 nm, 450 nm to 650 nm, 500 nm to 600 nm, or 500 nm to 550 nm.

[0107] In one embodiment, when the incident light is irradiated to the filter of the present application at the incident angles of 0 degree and 30 degrees, respectively, the center wavelength of the passband is shifted, and the shift is 1.4 nm or less, for example, 1.4 nm, 1.3 nm, 1.2 nm, or 1.1 nm. In one embodiment, when the incident light is irradiated to the filter of the present application at the incident angles of 0 degree and 35 degrees, respectively, the center wavelength of the passband is shifted, and the shift is 1.9 nm or less, for example, 1.9 nm, 1.8 nm, or 1.7 nm.

[0108] The present application will be described in further detail in accordance with the following specific examples, however, these specific examples are by no means intended to limit the scope of the present application.

[0109] Preparation Example 1

[0110] Near-infrared absorbing layer

[0111] 150 parts by weight of copper acetate was mixed with 15000 parts by weight of ethanol, and stirred at room temperature for 1.5 hours to form a first mixed solution; 20 parts by weight of a phosphorus-containing compound shown in Formula 2 (plysurf A242G, purchased from Japan First Industrial Co., Ltd.), 20 parts by weight of a phosphorus-containing compound shown in Formula 3 (plysurf W542C, purchased from Japan First Industrial Co., Ltd.), and 50 parts by weight of a phosphorus-containing compound shown in Formula 4 (plysurf A285C, purchased from Japan First Industrial Co., Ltd.) were mixed with 1500 parts by weight of ethanol to form a second mixed solution. The first mixed solution and the second mixed solution were mixed, and stirred at room temperature for 1 hour, then 100 parts by weight of butyl phosphonic acid was added, and the reaction was carried out at room temperature for 3 hours. Then it was put into an oven at 85°C for 12 hours to obtain a powder. The powder was mixed with xylene at a weight ratio of 1:3 to form a dispersion liquid, and the dispersion liquid was mixed with an optical resin at a weight ratio of 0.65:0.35 to form a coating liquid, which was then coated on a substrate, and baked at a temperature of 70°C for 30 minutes to obtain a near-infrared absorbing layer. The transmittance curve of the near-infrared absorbing layer is shown in FIG. 1. Figure 7

[0112] ​The near-infrared absorbing layer described above was subjected to X-ray photoelectron (ESCA / XPS) analysis, and the X-ray photoelectron spectrum thereof is shown in Fig. 1. It can be observed that there are characteristic peaks associated with copper complexes (Cu(POx)y, CuO, Cu2O, Cu(OH)2) at a binding energy of 930 eV to 940 eV. In addition, peaks appearing at a binding energy of 940 eV or more are satellite peaks. Figure 5

[0113] Filter layer

[0114] A first absorbing dye layer was prepared by adding 0.02 g of a squarylium compound and a cyanine compound as infrared absorbing dyes to 5 g of an epoxy resin, coating the mixture on a substrate, and baking the mixture at a temperature of 70°C for 30 minutes. A second absorbing dye layer was prepared by adding 0.02 g of a triazine compound as an ultraviolet absorbing dye to 5 g of an epoxy resin, coating the mixture on a substrate, and baking the mixture at a temperature of 70°C for 30 minutes.

[0115] A transmittance curve of the first absorbing dye layer and the second absorbing dye layer described above is shown in Fig. 2. Figure 6

[0116] In addition, a first absorbing dye layer was formed on a substrate as described above, and a second absorbing dye layer was formed on the first absorbing dye layer to prepare a filter layer having a double-layer structure, and a transmittance curve thereof is shown in Fig. 3. Figure 7

[0117] Preparation Example 2

[0118] A blue glass was used as a substrate layer in accordance with the contents of the specification. Then, a filter layer was formed on one side of the blue glass substrate layer in accordance with the method described in Preparation Example 1. Then, a near-infrared absorbing layer was formed on the other side of the blue glass substrate layer in accordance with the method described in Preparation Example 1. A transmittance curve of the substrate layer, the double-layer structure of the substrate layer + filter layer, and the triple-layer structure of the substrate layer + near-infrared absorbing layer + filter layer is shown in Fig. 4. Figure 8 As can be seen from the results, the filter having only the double-layer structure of the substrate layer + filter layer was insufficient in the cutoff effect with respect to near-infrared incident light. In contrast, the filter having the triple-layer structure of the substrate layer + near-infrared absorbing layer + filter layer exhibited an excellent cutoff effect with respect to near-infrared incident light, particularly incident light having a wavelength of 850 nm or more. It can be seen from this that the near-infrared absorbing layer contributes to the cutoff effect of near-infrared light, and the substrate layer + near-infrared absorbing layer of the present application can greatly improve the cutoff effect of near-infrared light while maintaining a high transmittance in the visible light region.

[0119] Example 1

[0120] The configuration of each layer structure in the filter of Example 1 is shown in Fig. 5. Figure 2 ​​​The filter was prepared according to the method of Example 1, but the thickness of the near-infrared absorbing layer was changed to 146.22 μm, 147.44 μm and 146.63 μm, as Examples 2 to 4. In addition, the filter was prepared according to the method of Example 1, but the thickness of the near-infrared absorbing layer was changed to 165.11 μm, as Comparative Example 1.

[0121] Examples 2 to 4 and Comparative Example 1

[0122] The filter was prepared according to the method of Example 1, but the thickness of the near-infrared absorbing layer was changed to 146.22 μm, 147.44 μm and 146.63 μm, as Examples 2 to 4. In addition, the filter was prepared according to the method of Example 1, but the thickness of the near-infrared absorbing layer was changed to 165.11 μm, as Comparative Example 1.

[0123] The transmittance curves of Examples 1 to 4 and Comparative Example 1 are shown in Figures 9 to 12 The transmittance data are shown in Table 1 below.

[0124] Table 1

[0125]

[0126] According to these results, the filter of the present application has very high cutoff property for the wavelength of incident light of 930 nm to 950 nm, even reaching an OD value of 4.5 or more. To further show the OD value of the filter of the present application for the wavelength of incident light of 930 nm to 950 nm, the transmittance curve and data were made into Figure 13 which is the OD value curve of the filter of Examples 1 to 4 for the wavelength of 930 nm to 950 nm. On the other hand, the filter of the present application has excellent transmittance for visible light, has a passband overlapping the wavelength range of 350 nm to 850 nm, and has a center wavelength of the passband in the wavelength range of 350 nm to 850 nm.

[0127] Figure 14 To observe the shift amount by irradiating the transmittance spectrum of the filter of Example 1 with incident light at different angles of 0 degree, 30 degrees and 35 degrees. Similarly, Figure 15The transmittance spectrum of the filter of Example 3 was irradiated with light at different angles of incidence of 0 degrees, 30 degrees, and 35 degrees. The results show that the transmittance curves obtained by irradiating the filter at different angles of incidence are highly similar. For example, taking the transmittance data of Example 1 and Example 3 as examples (as shown in Table 2 below), when irradiated at 0 degrees and 30 degrees, respectively, the shift amplitude of the center wavelength of the passband is 1.1 nm and 1.4 nm, respectively; when irradiated at 0 degrees and 35 degrees, respectively, the shift amplitude of the center wavelength of the passband is 1.7 nm and 1.9 nm, respectively. In comparison, the filter of Comparative Example 2, which is prepared according to the method of Example 1 but without the near-infrared absorbing layer, when irradiated at 0 degrees and 30 degrees, respectively, the shift amplitude of the center wavelength of the passband is as high as 9.6 nm; when irradiated at 0 degrees and 35 degrees, respectively, the shift amplitude of the center wavelength of the passband is even as high as 10.1 nm, showing a large shift amplitude. As is well known, such a shift will cause glare and ghosting if the amplitude is large, and the filter of the present application exhibits a low shift amplitude, thereby significantly reducing glare and ghosting and improving image quality.

[0128] Table 2

[0129] Example 1 0 degree incidence 30 degree incidence 35 degree incidence Transmittance at 50% (UV region) T 50％UV ]] 414.1 nm 414.0 nm 414.0 nm Transmittance at 50% (IR region) T 50％IR ]] 628.9 nm 626.86 nm 625.56 nm Center wavelength = (T 50％UV +T 50％IR ) / 2 521.5 nm 520.4 nm 519.8 nm Shift from 0 degree incidence / 1.1 nm 1.7 nm Example 3 0 degree incidence 30 degree incidence 35 degree incidence [CAT 50％UV ]]> 415.2 nm 414.8 nm 414.4 nm [TECHNICAL FIELD] 50％IR ]] 629.9 nm 627.7 nm 626.9 nm Center wavelength = (T 50％UV +T 50％IR ) / 2 522.6 nm 521.2 nm 520.7 nm Shift from 0 degree incidence / 1.4 nm 1.9 nm Comparative Example 2 0 degree incidence 30 degree incidence 35 degree incidence [CAT 50％UV ]] 414.6 406.7 nm 406.4 nm [CAT 50％IR ]] 628.2 nm 616.9 nm 616.2 nm Center wavelength = (T 50％UV +T 50％IR ) / 2 521.4 nm 511.8 nm 511.3 nm Shift from 0 degree incidence / 9.6 nm 10.1 nm Comparative Example 2 0 degree incidence 30 degree incidence 35 degree incidence 406.7 nm 406.4 nm 628.2 nm 616.9 nm 616.2 nm 521.4 nm 511.8 nm 511.3 nm Shift from 0 degree incidence 9.6 nm 10.1 nm Comparative Example 2 0 degree incidence 30 degree incidence 35 degree incidence 406.7 nm 406.4 nm 628.2 nm 616.9 nm 616.2 nm 521.4 nm 511.8 nm 511.3 nm Shift from 0 degree incidence 9.6 nm 10.1 nm Comparative Example 2 0 degree incidence 30 degree incidence 35 degree incidence 406.7 nm 406.4 nm 628.2 nm 616.9 nm 616.2 nm 521.4 nm 511.8 nm 511.3 nm Shift from 0 degree incidence 9.6 nm 10.1 nm Comparative Example 2 0 degree incidence 30 degree incidence 35 degree incidence 406.7 nm 406.4 nm 628.2 nm 616.9 nm 616.2 nm 521.4 nm 511.8 nm 511.3 nm Shift from 0 degree incidence 9.6 nm 10.1 nm Comparative Example 2 0 degree incidence 30 degree incidence 35 degree incidence 406.7 nm 406.4 nm 628.2 nm 616.9 nm 616.2 nm 521.4 nm 511.8 nm 511.3 nm

[0130] The above embodiments and specific examples are not intended to limit the present application, and the technical features or schemes listed can be combined with each other, and the present application can be implemented or applied by other different embodiments, and the details described herein can be changed or modified according to different viewpoints and applications without departing from the present application.

Claims

1. An optical filter, characterized by, Comprising: a base layer; and a near-infrared absorbing layer on the base layer, wherein the near-infrared absorbing layer comprises: a copper complex formed from a copper compound to provide copper ions, a phosphonic acid represented by Formula 1 below, and a phosphorus-containing compound represented by Formulae 2 to 4, [Formula 1] [Formula 2] [Formula 3] [Formula 4] wherein R, R1, R2, R3 are each independently a substituted or unsubstituted C1to C 12 alkyl or a substituted or unsubstituted C6to C 12 aryl; the unsubstituted C1to C 12 alkyl is selected from the group consisting of methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, i-butyl, t-butyl and pentyl; the substituted C1to C 12 alkyl is selected from the group consisting of haloalkyl, hydroxyalkyl, nitroalkyl, and alkoxyalkyl; the unsubstituted C6to C 12 aryl is selected from the group consisting of phenyl and naphthyl; and the substituted C6to C 12 aryl is selected from the group consisting of haloaryl, nitroaryl, hydroxyaryl, alkoxyaryl, alkylaryl, haloalkylaryl, nitroalkylaryl and hydroxyalkylaryl; wherein the optical filter has an OD value of greater than 4 for a 930 nm to 950 nm incident light wavelength.

2. The filter according to claim 1, characterized in that said unsubstituted C1to C4alkyl is selected from the group consisting of methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, i-butyl and t-butyl; said unsubstituted C6to C10aryl is selected from the group consisting of chlorophenyl. 12 said unsubstituted C1to C4alkyl is selected from the group consisting of methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, i-butyl and t-butyl; said unsubstituted C6to C10aryl is selected from the group consisting of chlorophenyl. 12 said unsubstituted C1to C4alkyl is selected from the group 3. The filter of claim 1, wherein The near-infrared absorbing layer has a haze of 0.4% or less.

4. The filter of claim 1, wherein The near-infrared absorbing layer has at least one main peak in X-ray photoelectron spectroscopy at a binding energy of 930 electron volts to 940 electron volts.

5. The filter of claim 4, wherein, The at least one main peak has a count per second value of 4500 or more.

6. The filter of claim 1, wherein, The optical filter has an OD value of greater than 4.5 for a 940 nm incident light wavelength.

7. The filter of claim 1, wherein The near-infrared absorbing layer has a thickness of 25 μm to 150 μm.

8. The filter of claim 1, wherein, The base layer has a material of glass and a thickness of 200 μm to 500 μm.

9. The filter of claim 1, wherein, Further comprising a light-filtering layer on the other side of the base layer relative to the near-infrared absorbing layer.

10. The filter according to claim 9, characterized in that The light-filtering layer further comprises a first absorbing dye layer and / or a second absorbing dye layer, the first absorbing dye layer comprising a near-infrared absorbing dye, and the second absorbing dye layer comprising an ultraviolet absorbing dye.

11. The filter of claim 10, wherein, The near-infrared absorbing dye is at least one selected from the group consisting of an azo-based compound, a hydrazine-based compound, a dithiol metal complex, a squarylium-based compound, a cyanine-based compound, and a phthalocyanine-based compound.

12. The filter of claim 10, wherein, The ultraviolet absorbing dye is at least one selected from the group consisting of an azomethine-based compound, an indole-based compound, a ketone-based compound, a benzimidazole-based compound, and a triazine-based compound.

13. The filter of claim 10, wherein, The first absorbing dye layer and the second absorbing dye layer each have a thickness of 0.5 μm to 10 μm, and the light-filtering layer has a total thickness of 0.5 μm to 10 μm.

14. The filter of claim 1, wherein, Further comprising at least one anti-reflection layer on the outermost side of the optical filter.

15. The filter of claim 14, wherein, The at least one anti-reflection layer has a material selected from at least one of TiO2, SiO2, Y2O3, MgF2, Al2O3, Nb2O5, AlF3, Bi2O3, Gd2O3, LaF3, PbTe, Sb2O3, SiO, SiN, Ta2Os, ZnS, ZnSe, ZrO2, and Na3AlF6, and a thickness of 0.5 μm to 10 μm.

16. The filter of claim 14, wherein, Further comprising a protective layer, and the protective layer has a material of an optical resin.

17. The filter of claim 16, wherein, The protective layer has a thickness of 10 μm to 30 μm, and is positioned between the near-infrared absorbing layer and the anti-reflection layer.

18. The filter of claim 1, wherein, The optical filter has a total thickness of 225 μm to 800 μm.

19. The filter of claim 1, wherein, The optical filter has a haze of 0.5% or less.

20. The filter of claim 1, wherein, The optical filter has a maximum transmittance of 0.01% or less for a 930 nm to 950 nm incident light wavelength range.

21. The filter of claim 20, wherein, The optical filter has a maximum transmittance of 0.005% or less for a 930 nm to 950 nm incident light wavelength range.

22. The filter of claim 1, wherein, The optical filter has a minimum transmittance of 80% or more for a 460 nm to 560 nm incident light wavelength range.

23. The filter of claim 22, wherein, The minimum transmittance of the optical filter to the wavelength range of 460 nm to 560 nm of incident light is 85% or more.

24. The filter of claim 1, wherein, The optical filter has a passband overlapping the wavelength range of 350 nm to 850 nm, and a center wavelength of the passband is in the wavelength range of 350 nm to 850 nm.

25. The filter of claim 24, wherein, When the incident light irradiates the optical filter at an incident angle of 0 degree and 30 degrees respectively, the center wavelength of the passband has a shift, and the shift amplitude is 1.4 nm or less.

26. The filter of claim 24, wherein, When the incident light irradiates the optical filter at an incident angle of 0 degree and 35 degrees respectively, the center wavelength of the passband has a shift, and the shift amplitude is 1.9 nm or less.

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