Optical filter

Abstract

Disclosed is an optical filter including a base layer and a near-infrared absorbing layer on the base layer, in which the near-infrared absorbing layer includes: a copper complex formed of a copper compound for providing copper ions, a phosphonic acid represented by Formula 1 herein, and at least one phosphorus-containing compound represented by Formula 2 to Formula 4 herein, the OD value of the optical filter to the wavelength of incident light ranging from 930 nm to 950 nm is larger than 4. By arranging the specific near infrared ray absorption layer on the optical filter, the optical filter can efficiently absorb near infrared rays and has excellent visible light transmittance, and the burden of subsequent processing can be relieved.

Description

Technical Field

[0001] The present invention relates to an optical filter, in particular to an optical filter comprising a near infrared ray absorption layer, wherein the near infrared ray absorption layer comprises a copper complex. Background Art

[0002] Near-infrared absorption filters are widely used in optical devices, such as image sensors. As the market's requirements for imaging accuracy and pattern optical quality continue to increase, current near-infrared absorption filters can no longer meet new demands. Therefore, it is necessary to develop near-infrared absorption filters that have good transmittance in the visible light region and good shielding properties in the near-infrared region (i.e., low transmittance, lower than the current 8 to 15% transmittance) to meet the stringent requirements of the current standards that are constantly improving.

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

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

[0005] Furthermore, although the light filtering effect can be enhanced by increasing the coating thickness, the material processing and process difficulty will deteriorate with the increase of coating thickness and complexity, and the loss rate will also increase, which will in turn increase the cost and thus lead to a decrease in industrial utilization. The increase in coating thickness also causes the image quality to deteriorate, which is inconsistent with the current market trend of pursuing high definition. Summary of the invention

[0006] In view of the above problems, the present invention provides a filter, which comprises:

[0007] basal layer; and

[0008] A near infrared absorbing layer is located on the substrate layer, wherein the near infrared absorbing layer comprises:

[0009] A copper complex, which is formed by a copper compound for providing copper ions, a phosphonic acid as shown in Formula 1 below, and at least one phosphorus-containing compound as shown in Formulas 2 to 4,

[0010]

[0011] wherein R, R1, R2, and R3 are each independently substituted or unsubstituted C1 to C 12 Alkyl or substituted or unsubstituted C6 to C 12 Aryl,

[0012] The OD value of the filter for incident light wavelengths from 930nm to 950nm is greater than 4.

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

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

[0015] In one embodiment, the X-ray photoelectron spectrum of the near infrared absorbing layer has at least one main peak at a binding energy of 930 eV to 940 eV. In another embodiment, the counts per second value of at least one main peak in the X-ray photoelectron spectrum is greater than 4500.

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

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

[0018] In one embodiment, the near infrared ray absorbing layer further comprises an optical resin, and the copper complex is dispersed in the optical resin. In one embodiment, the optical resin is a thermoplastic resin and / or a photocurable resin. In one embodiment, the optical resin is selected from polycarbonates, polyesters, polycycloolefins, polyacrylic acids, siloxane resins, and polyimides.

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

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

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

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

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

[0024] In one embodiment, the thickness of the first absorption dye layer and the second absorption dye layer are respectively 0.5 μm to 10 μm, and the total thickness of the filter layer is 0.5 μm to 10 μm.

[0025] In one embodiment, the optical filter further comprises at least one anti-reflection layer located at the outermost side of the optical filter.

[0026] In one embodiment, the material of at least one anti-reflective layer is selected from at least one of TiO2, SiO2, Y2O3, MgF2, A12O3, Nb2O5, AlF3, Bi2O3, Gd2O3, LaF3, PbTe, Sb2O3, SiO, SiN, Ta2Os, ZnS, ZnSe, ZrO2 and Na3AlF6, and the thickness is 0.5 μm to 10 μm.

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

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

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

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

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

[0032] In one embodiment, the maximum transmittance of the filter for incident light in the wavelength range of 930nm to 950nm is less than 0.01%; the maximum transmittance for incident light in the wavelength range of 930nm to 950nm is less than 0.005%; the minimum transmittance for incident light in the wavelength range of 460nm to 560nm is greater than 80%; and the minimum transmittance for incident light in the wavelength range of 460nm to 560nm is greater than 85%.

[0033] In one embodiment, when the incident light irradiates the filter at incident angles of 0 degrees and 30 degrees, respectively, the central wavelength of the passband of the filter is shifted, and the shift amplitude is less than 1.4nm; when the incident light irradiates the filter at incident angles of 0 degrees and 35 degrees, respectively, the central wavelength of the passband of the filter is shifted, and the shift amplitude is less than 1.9nm.

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

[0035] Figures 1A to 1C , Figures 2 to 4 is a schematic diagram of the structure of the optical filter of the present invention;

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

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

[0038] Figure 7 The transmittance curve of AF32 glass and the transmittance curve of the filter layer and the near-infrared absorption layer in Preparation Example 1;

[0039] Figure 8 The transmittance curves of three implementation schemes, namely, the base layer, the base layer + the filter layer, and the base layer + the near-infrared absorption layer + the filter layer in Preparation Example 1;

[0040] Fig. 9 is a transmittance curve diagram of the optical filters of Example 1 and Comparative Example 1;

[0041] Fig.10 is a transmittance curve diagram of the optical filters of Example 2 and Comparative Example 1;

[0042] Fig.11is a transmittance curve diagram of the optical filters of Example 3 and Comparative Example 1;

[0043] Fig.12 is a transmittance curve diagram of the optical filters of Example 4 and Comparative Example 1;

[0044] Fig.13 OD value curves of the optical filters of Examples 1 to 4 for incident light wavelengths of 930 nm to 950 nm;

[0045] Fig.14 is a transmittance curve diagram of the filter of Example 1 when incident angles are 0 degrees, 30 degrees, and 35 degrees respectively;

[0046] Fig.15 is a transmittance curve diagram of the filter of Example 3 when incident angles are 0 degrees, 30 degrees, and 35 degrees respectively;

[0047] Main component symbols

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

[0049] 10-near infrared absorption layer;

[0050] 11- adhesive layer;

[0051] 12- protective layer;

[0052] 20 - basal 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 following describes the implementation of the present invention through specific embodiments. Those skilled in the art can easily understand the scope and effectiveness of the present invention based on the contents described herein.

[0058] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents described in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions under which the present invention can be implemented, and therefore have no substantial technical significance. Any structural modification, change in proportional relationship, or adjustment of size, without affecting the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical content described in the present invention. At the same time, the terms such as "upper", "first", "second", etc. cited in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0059] When “includes,” “comprising,” or “has” specific elements as described herein, unless otherwise stated, other elements, components, structures, regions, parts, devices, systems, steps, or connections may also be included, rather than excluding these other elements.

[0060] Unless clearly stated otherwise herein, the singular forms "a", "an" and "the" described herein also include plural forms, and "or" and "and / or" described herein are used interchangeably.

[0061] The numerical ranges described herein are inclusive and combinable, and any numerical value falling within the numerical range described herein can be used as the maximum value or the minimum value to derive its sub-range; for example, the numerical range of "25 to 200" should be understood to include any sub-range between endpoint 25 and endpoint 200, such as 25 to 150, 30 to 200, 30 to 150... and other sub-ranges; in addition, if a numerical value falls within the ranges described herein (such as between the maximum value and the minimum value), it should be deemed to be included in the scope of the present invention.

[0062] The present invention mainly provides an optical filter. Specifically, the optical filter of the present invention comprises a base layer and a near infrared ray absorption layer located on the base layer.

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

[0064] The copper compound is mainly used as a supply 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 listed as copper acetate or a hydrate of copper acetate, and can also be listed as an anhydride or hydrate of copper chloride, copper formate, copper stearate, copper benzoate, copper pyrophosphate, copper naphthenate, and copper citrate. In one embodiment, the copper compound is copper acetate.

[0065] Phosphonic acid is shown in the following formula 1,

[0066]

[0067] Wherein, R is a substituted or unsubstituted C1 to C12 alkyl group or a substituted or unsubstituted C6 to C12 aryl group.

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

[0069] The phosphorus-containing compounds are shown in Formula 2 to Formula 4 below:

[0070]

[0071] Wherein, R, R1, R2, and R3 are each independently a C1 to C12 alkyl group or a C6 to C12 aryl group, which is defined as described for R in Formula 1.

[0072] The phosphorus-containing compound can have a dispersing function, so that the components in the composition (including the formed copper complex) do not agglomerate with each other and achieve uniform dispersion. One of the effects of this function is that the crystallite size can be less than 100nm, further between 5nm and 80nm, or between 20nm and 60nm, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100nm. When the crystallite size is above 5nm, sufficient near-infrared absorption characteristics can be displayed; and when the crystallite size is below 100nm, the particle number is small and the particle size is small, and the product made of the near-infrared absorbing composition has a lower haze. In the present invention, in order to prepare the near-infrared absorbing composition, at least one phosphorus-containing compound shown in Formula 2 to Formula 4 is used.

[0073] The copper compound, phosphonic acid and phosphorus-containing compound in the near-infrared absorbing composition can be adjusted in proportion as required. For example, in the near-infrared absorbing composition, the copper compound can be 150 parts by weight, which can be 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, The amount of the phosphorus-containing compound can be 1 to 90 parts by weight, which can be 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 phosphorus-containing compound can be 1 to 90 parts by weight in total, which can be 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 one embodiment, the near-infrared absorbing composition of the present invention includes the phosphorus-containing compounds shown in Formula 2 to Formula 4 at the same time, and the proportion can be adjusted according to the needs. For example, in the near-infrared absorbing composition, the phosphorus-containing compound shown in Formula 2 can be 1 to 90 parts by weight, the phosphorus-containing compound shown in Formula 3 can be 1 to 90 parts by weight, and the phosphorus-containing compound shown in Formula 4 can be 1 to 90 parts by weight, wherein the phosphorus-containing compounds shown in Formula 2 to Formula 4 can be listed as 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 shown in Formula 2: the phosphorus-containing compound shown in Formula 3: the phosphorus-containing compound shown in Formula 4 is 20:20:50.

[0075] In one embodiment, the near infrared absorbing composition of the present invention may be in the form of a dispersion, that is, in addition to the copper compound, phosphonic acid and phosphorus-containing compound, further comprising a solvent. During preparation, the copper compound, phosphonic acid and phosphorus-containing compound may be added to the solvent and mixed, and the ratio of these components to the solvent may be 1:5 to 1:1, for example 1:3, but not limited thereto.

[0076] The solvent may be selected from known ones, including but not limited to water, alcohols, ketones, ethers, esters, aromatic hydrocarbons, halogenated hydrocarbons, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, cyclopentane, etc. Specifically, alcohols include methanol, ethanol, propanol, etc. Esters include alkyl formates, alkyl acetates, alkyl propionates, alkyl butyrates, alkyl lactates, alkyl alkoxy acetates, alkyl 3-alkoxy propionates, alkyl 2-alkoxy propionates, alkyl 2-alkoxy-2-methylpropionates, alkyl pyruvates, alkyl acetoacetates, alkyl 2-oxobutyrates, etc. Examples of ethers include 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, etc. Examples of ketones include methyl ethyl ketone, cyclohexanone, cyclopentanone, 2-heptanone, 3-heptanone, etc. Examples of aromatic hydrocarbons include toluene and xylene, etc.

[0077] Mixing, for example, stirring fully at room temperature (such as 25° C.), for example, stirring for more than 4 hours, more than 6 hours, or more than 8 hours, but not limited thereto.

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

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

[0080] The optical resin may be a thermoplastic resin and / or a photocurable resin. In one embodiment, the optical resin is selected from polycarbonates, polyesters, polycycloolefins, polyacrylic acids, siloxane resins and polyimides. In one embodiment, the optical resin is a siloxane resin.

[0081] In addition, a curing agent, such as a photocuring agent, may be further added to perform a curing process, so that the film may be cured by light irradiation.

[0082] In one embodiment, the near infrared absorbing layer of the present invention has a haze of less than 0.4%, 0.3% or 0.2%, 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 absorption layer also affects the characteristics of near-infrared absorption. Generally speaking, as the thickness of the near-infrared absorption layer increases, the near-infrared cutoff ability also increases, but it does not meet the demand for thinness. On the other hand, as the thickness of the near-infrared absorption layer decreases, the near-infrared cutoff ability also decreases. In one embodiment, the near-infrared absorbing layer of the present invention can also achieve excellent near-infrared cutoff ability even when it is relatively thin. Specifically, the thickness of the near-infrared absorbing layer is between 25μm and 150μm, between 50μm and 150μm, or between 100μm and 150μm, for example, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 110μm, 120μm, 125μm, 130μm, 135μm, 140μm, 145μm, 146μm, 147μm or 150μm.

[0084] In one embodiment, the X-ray photoelectron spectrum of the near infrared absorbing layer of the present invention has at least one main peak at a binding energy of 930 electron volts to 940 electron volts. In one embodiment, the counts per second 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 maximum transmittance of the near infrared absorbing layer of the present invention for incident light in the wavelength range of 930 nm to 950 nm (including incident light at 940 nm) is 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, 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%; ​​on the other hand, the OD value for the incident light wavelength range of 930nm to 950nm (including the incident light of 940nm) is 3 or more, greater than 3, greater than 3.5, greater than 3.5, greater than 4, greater than 4.5, or greater 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. In one embodiment, the minimum transmittance of the near infrared absorbing layer of the present invention for incident light in the wavelength range of 460nm to 560nm is 80% or more or 85% or more, for example, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89% or 90%.

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

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

[0088] In one embodiment, the base layer is blue glass, wherein the molar ratio of phosphorus / (aluminum+lanthanum+niobium+yttrium) may be 1.5 to 16, and the molar ratio of fluorine / (fluorine+oxygen) may be 0.01 to 0.2. In one embodiment, the blue glass contains 35 to 55 mol% of phosphorus, 3.5 to 15 mol% of aluminum, 15 to 25 mol% of alkali metals, 10 to 35 mol% of alkaline earth metals and divalent metals, 10 to 21 mol% of copper, and 0 to 7 mol% of the total of lanthanum+niobium+yttrium elements, 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 one 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 invention is not limited. For example, Figure 1A As shown, the optical filter 1 includes a near infrared ray absorbing layer 10 and a base layer 20 , wherein the near infrared ray absorbing layer 10 is located on the base layer 20 .

[0091] In one embodiment, the optical filter of the present invention further comprises a filter layer. In one embodiment, the position of the filter layer in the optical filter is not limited. For example, Figure 1AAs shown in FIG. 1 , the filter layer 30 is located on the other side of the substrate layer 20 relative to the near infrared absorption layer 10, that is, the near infrared absorption layer 10 and the filter layer 30 are located on both sides of the substrate layer 20. Figure 3 As shown, the filter layer 30 in the filter 1" is located between the near infrared absorption layer 10 and the base layer 20; Figure 4 As shown, the near infrared absorption layer 10 in the optical filter 1 ″′ is located between the optical filter layer 30 and the base layer 20 .

[0092] The filter layer is used to assist the near infrared absorbing layer in exhibiting better optical properties, for example, to further enhance the cutoff effect on near infrared and / or ultraviolet rays. In one embodiment, the filter layer may 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. Figure 1B and 1C As shown, the filter layer 30 in the filter 1 is specifically a double-layer structure of a first absorbing dye layer 31 and a second absorbing dye layer 32. Figure 1B and 1C The only difference lies in the arrangement order of the first absorbing dye layer 31 and the second absorbing dye layer 32 .

[0093] The filter layer may include a transparent resin material, including but not limited to epoxy resin, polyurethane, polyacrylate, polyolefin, polycarbonate, polycycloolefin and polyvinyl butyral. The resin material may serve as a base for the filter layer coating liquid.

[0094] Near infrared absorbing dyes such as azo compounds, diimmonium compounds, dithiol metal complexes, squaraine compounds, cyanine compounds and phthalocyanine compounds can adjust the maximum absorption wavelength to between 650 and 1100 nm, or more specifically between 650 and 750 nm. Ultraviolet absorbing dyes such as azomethine compounds, indole compounds, ketone compounds, benzimidazole compounds and triazine compounds.

[0095] In one embodiment, the thickness of the filter layer is 0.5 μm to 10 μm, such as 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm. When the filter layer is a multi-layer structure, such as a double-layer structure of a first absorption dye layer and a second absorption dye layer, the thickness of each layer is 0.5 μm to 10 μm, such as 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 optical filter of the present invention further comprises at least one anti-reflection layer, which is located on the outermost side of the optical filter. Figure 2 As shown, the anti-reflection layer 40 is located on the outermost sides of the filter 1 ′.

[0097] In one embodiment, the anti-reflection layer is a coating formed of at least one material selected from TiO2, SiO2, Y2O3, MgF2, A12O3, Nb2O5, AlF3, Bi2O3, Gd2O3, LaF3, PbTe, Sb2O3, SiO, SiN, Ta2Os, ZnS, ZnSe, ZrO2 and Na3AlF6. In one embodiment, the anti-reflection layer is formed by alternating layers of TiO2 layers and SiO2 layers.

[0098] In one embodiment, the anti-reflection layer has a thickness of 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 optical filter of the present invention further comprises a protective layer, and the material of the protective layer is an optical resin. The optical resin here can refer to the optical resin used in the near infrared absorbing composition in the form of a coating liquid.

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

[0101] In one embodiment, the optical filter of the present invention further comprises an adhesive layer, which is located between the near infrared absorbing film and the base layer. Figure 2 As shown, the adhesive layer 11 is located between the near infrared absorbing layer 10 and the base layer 20. The adhesive layer can use materials known in the art for bonding two adjacent layers, for example, hexamethyldisilazane (HMDS) can be used. The adhesive layer is used to prevent the near infrared absorbing layer from being separated from the base layer under certain conditions, so as to improve the stability of the filter.

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

[0103] In one embodiment, the total thickness of the filter of the present invention is about 225 μm to about 800 μm, about 250 μm to about 500 μm, or about 300 μm to about 500 μm, for example, 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 invention has a haze of less than 0.5%, 0.4% or 0.3%, for example 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 maximum transmittance of the filter of the present invention for incident light in the wavelength range of 930nm to 950nm (including incident light at 940nm) is 0.01% or less, less than 0.01%, 0.005% or less, or less than 0.005%, for example, 0.01%, 0.009%, 0.008%, 0.007%, 0.006%, 0.005%, 0.004%, 0.003%, On the other hand, the OD value for the incident light wavelength range of 930nm to 950nm (including the incident light of 940nm) is 4 or more, greater than 4, 4.5 or more, greater than 4.5, 4.8 or more, or greater than 4.8, for example, 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 minimum transmittance of the filter of the present invention for the incident light wavelength range of 460nm to 560nm is 80% or more or 85% or more, for example, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%.

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

[0107] In one embodiment, when the incident light irradiates the optical filter of the present invention at an incident angle of 0 and 30 degrees, the central wavelength of the passband is shifted, and the shift amplitude is 1.4 nm or less, such as 1.4 nm, 1.3 nm, 1.2 nm or 1.1 nm. In one embodiment, when the incident light irradiates the optical filter of the present invention at an incident angle of 0 and 35 degrees, the central wavelength of the passband is shifted, and the shift amplitude is 1.9 nm or less, such as 1.9 nm, 1.8 nm or 1.7 nm.

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

[0109] Preparation Example 1

[0110] Near infrared absorption layer

[0111] 150 parts by weight of copper acetate and 15,000 parts by weight of ethanol were mixed and stirred at room temperature for 1.5 hours to form a first mixed solution; 20 parts by weight of the phosphorus-containing compound shown in formula 2 (plysurf A242G, purchased from Japan Daiichi Industry Pharmaceutical Co., Ltd.), 20 parts by weight of the phosphorus-containing compound shown in formula 3 (plysurf W542C, purchased from Japan Daiichi Industry Pharmaceutical Co., Ltd.) and 50 parts by weight of the phosphorus-containing compound shown in formula 4 (plysurf A285C, purchased from Japan Daiichi Industry Pharmaceutical Co., Ltd.) were mixed with 1,500 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, and then 100 parts by weight of butylphosphonic acid were added and stirred at room temperature for 3 hours. Then, the mixture was placed in an oven at 85°C for 12 hours to obtain a powder. The powder and xylene were mixed at a weight ratio of 1:3 to form a dispersion, and the dispersion was mixed with an optical resin at a weight ratio of 0.65:0.35 to form a coating solution, which was then coated on the substrate and baked at 70°C for 30 minutes to obtain a near-infrared absorption layer. The transmittance curve of the near-infrared absorption layer is shown in the figure. Figure 7 shown.

[0112] The near infrared absorbing layer is subjected to X-ray photoelectron (ESCA / XPS) analysis, and the X-ray photoelectron spectrum thereof is as follows: Figure 5 As shown. It can be observed that the characteristic peaks associated with copper complexes (Cu(POx)y, CuO, Cu2O, Cu(OH)2) are observed when the binding energy is 930eV to 940eV. In addition, the peaks that appear when the binding energy is above 940eV are satellite peaks.

[0113] Filter layer

[0114] 0.02 g of a square acid compound and a cyanine compound as infrared absorbing dyes were added to 5 g of epoxy resin, coated on a substrate, and baked at 70°C for 30 minutes to obtain a first absorbing dye layer; 0.02 g of a triazine compound as an ultraviolet absorbing dye was added to 5 g of epoxy resin, coated on a substrate, and baked at 70°C for 30 minutes to obtain a second absorbing dye layer.

[0115] The transmittance curves of the first absorbing dye layer and the second absorbing dye layer are as follows: Figure 6 shown.

[0116] In addition, as described above, a first absorbing dye layer is formed on the substrate, and a second absorbing dye layer is formed on the first absorbing dye layer to obtain a filter layer with a double-layer structure. The transmittance curve is shown in FIG. Figure 7 shown.

[0117] Preparation Example 2

[0118] According to the specification, blue glass is used as the base layer. Then, a filter layer is formed on one side of the blue glass base layer according to the method described in Preparation Example 1. Then, a near infrared absorption layer is formed on the other side of the blue glass base layer according to the method described in Preparation Example 1. The transmittance curves of the base layer, the double-layer structure of base layer + filter layer, and the three-layer structure of base layer + near infrared absorption layer + filter layer are shown in FIG. Figure 8 As shown. From the results, the filter with only a double-layer structure of base layer + filter layer has insufficient cutoff effect on near-infrared incident light. In contrast, the filter with a three-layer structure of base layer + near-infrared absorption layer + filter layer can show excellent cutoff effect on near-infrared incident light, especially those with a wavelength of more than 850nm. From this, the contribution of the near-infrared absorption layer can be concluded. The base layer + near-infrared absorption layer of the present invention can greatly improve the cutoff effect of near-infrared light and maintain high transmittance in the visible light segment.

[0119] Example 1

[0120] The structure of each layer in the filter of Example 1 is as follows Figure 2As shown, the base layer is blue glass with a thickness of 200 μm; the adhesive layer is hexamethyldisilazane with a thickness of 60 μm; the near-infrared absorption layer is prepared according to the method described in Preparation Example 1, with a thickness of 145.44 μm; the protective layer is optical resin with a thickness of 10 μm; the filter layer is prepared according to the method described in Preparation Example 1, with a thickness of 5 μm; the anti-reflection layer is alternately stacked TiO2 layers and SiO2 layers, with a total thickness of 1 μm.

[0121] Examples 2 to 4 and Comparative Example 1

[0122] According to the method of Example 1, optical filters were prepared, 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, according to the method of Example 1, optical filters were prepared, but the thickness of the near infrared absorbing layer was changed to 165.11 μm, as Comparative Example 1.

[0123] The transmittance curves of the above-mentioned Examples 1 to 4 and Comparative Example 1 are shown in FIG. 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 invention has a very high cutoff for incident light wavelengths of 930nm to 950nm, and even reaches an OD value of 4.5 or above. To further show the OD value of the filter of the present invention for incident light wavelengths of 930nm to 950nm, a transmittance curve and data were made. Fig.13 , which is a graph of OD values ​​of the filters of Examples 1 to 4 for wavelengths of 930nm to 950nm. On the other hand, the filter of the present invention has excellent transmittance to visible light, and has a passband overlapping with the wavelength range of 350nm to 850nm, and the center wavelength of the passband is within the wavelength range of 350nm to 850nm.

[0127] Fig.14 The transmittance spectrum of the filter of Example 1 is obtained by irradiating light at different angles of 0, 30, and 35 degrees, and the offset can be observed through this. Similarly, Fig.15The transmittance spectra of the filter of Example 3 are irradiated with light at different angles of 0, 30, and 35 degrees. The results show that the transmittance curves obtained by irradiating the filter at different incident angles are highly similar. For example, taking the transmittance data of Example 1 and Example 3 as an example (as shown in Table 2 below), when the incident light is at 0 and 30 degrees, the shift amplitude of the center wavelength of the passband is 1.1nm and 1.4nm respectively; when the incident light is at 0 and 35 degrees, the shift amplitude of the center wavelength of the passband is 1.7nm and 1.9nm respectively. In contrast, the filter of Comparative Example 2, which is prepared according to the method of Example 1 but does not have a near-infrared absorption layer, has a shift amplitude of up to 9.6nm when the incident light is at 0 and 30 degrees, respectively; when the incident light is at 0 and 35 degrees, the shift amplitude of the center wavelength of the passband is as high as 10.1nm, showing a large shift amplitude. It is well known that such a large offset will cause glare and ghosting. However, the filter of the present invention significantly reduces glare and ghosting and improves image quality because of its low offset amplitude.

[0128] Table 2

[0129] Example 1 0 degree incidence 30 degree incidence 35 degree incidence <![CDATA[Corresponding wavelength at 50% transmittance (UV region) T 50％UV > 414.1nm 414.0nm 414.0nm <![CDATA[Corresponding wavelength at 50% transmittance (IR region) T 50％IR > 628.9nm 626.86nm 625.56nm <![CDATA[Central wavelength = (T 50％UV + T 50％IR ) / 2]]> 521.5nm 520.4nm 519.8nm The deviation compared to 0 degree incidence / 1.1 nm 1.7nm Example 3 0 degree incidence 30 degree incidence 35 degree incidence <![CDATA[T 50％UV ]]> 415.2nm 414.8nm 414.4nm <![CDATA[T 50％IR ]]> 629.9nm 627.7nm 626.9nm <![CDATA[Central wavelength = (T 50％UV + T 50％IR ) / 2]]> 522.6nm 521.2nm 520.7nm The deviation compared to 0 degrees of incidence / 1.4 nm 1.9nm Comparative Example 2 0 degree incidence 30 degree incidence 35 degree incidence <![CDATA[T 50％UV ]]> 414.6 406.7nm 406.4nm <![CDATA[T 50％IR ]]> 628.2nm 616.9nm 616.2nm <![CDATA[Central wavelength = (T 50％UV + T 50％IR ) / 2]]> 521.4nm 511.8nm 511.3nm The deviation compared to 0 degrees of incidence / 9.6nm 10.1nm

[0130] The above-mentioned implementation modes and specific examples are not intended to limit the present invention. The listed technical features or schemes can be combined with each other. The present invention can also be implemented or applied through other different implementation modes. The details recorded in this document can also be given different changes or modifications according to different viewpoints and applications without departing from the present invention.

Claims

1. A filter, characterized in that: include: Basal layer; as well as A near infrared absorbing layer is located on the base layer, wherein the near infrared absorbing layer comprises: A copper complex is formed by a copper compound for providing copper ions, a phosphonic acid as shown in Formula 1 below, and at least one phosphorus-containing compound as shown in Formulas 2 to 4, wherein R, R1, R2, and R3 are each independently substituted or unsubstituted C1 to C 12 Alkyl or substituted or unsubstituted C6 to C 12 Aryl, Wherein, the OD value of the filter for incident light wavelengths from 930nm to 950nm is greater than 4.

2. The optical filter according to claim 1, characterized in that: The substituted or unsubstituted C1 to C 12 The alkyl group is selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and tert-butyl; the substituted or unsubstituted C6 to C 12 The aryl group is selected from the group consisting of phenyl, naphthyl and chlorophenyl.

3. The optical filter according to claim 1, characterized in that: The near infrared absorbing layer has a haze of 0.4% or less.

4. The optical filter according to claim 1, characterized in that The X-ray photoelectron spectrum of the near infrared absorption layer has at least one main peak when the binding energy is 930 electron volts to 940 electron volts.

5. The optical filter according to claim 4, characterized in that: The counts per second of the at least one main peak is greater than 4500.

6. The optical filter according to claim 1, characterized in that: The OD value of the filter for incident light wavelength of 940 nm is greater than 4.

5.

7. The optical filter according to claim 1, characterized in that: The near infrared absorbing layer has a thickness of 25 μm to 150 μm.

8. The optical filter according to claim 1, characterized in that: The base layer is made of glass, and has a thickness of 200 μm to 500 μm.

9. The optical filter according to claim 1, characterized in that: The invention also comprises a filter layer, wherein the filter layer is located on the other side of the base layer relative to the near infrared ray absorption layer.

10. The optical filter according to claim 9, characterized in that: The filter layer further includes a first absorption dye layer and / or a second absorption dye layer, the first absorption dye layer includes a near infrared absorption dye, and the second absorption dye layer includes an ultraviolet absorption dye.

11. The optical filter according to claim 10, characterized in that: The near infrared absorbing dye is at least one selected from the group consisting of azo compounds, diimmonium compounds, dithiol metal complexes, squarylium compounds, cyanine compounds, and phthalocyanine compounds.

12. The optical filter according to claim 10, characterized in that: The ultraviolet absorbing dye is at least one selected from the group consisting of azomethine compounds, indole compounds, ketone compounds, benzimidazole compounds and triazine compounds.

13. The optical filter according to claim 10, characterized in that: The thickness of the first absorption dye layer and the second absorption dye layer are respectively 0.5 μm to 10 μm, and the total thickness of the filter layer is 0.5 μm to 10 μm.

14. The optical filter according to claim 1, characterized in that: It also includes at least one anti-reflection layer, and the anti-reflection layer is located on the outermost side of the filter.

15. The optical filter according to claim 14, characterized in that: The material of the at least one anti-reflection layer is selected from at least one of TiO2, SiO2, Y2O3, MgF2, A12O3, Nb2O5, AlF3, Bi2O3, Gd2O3, LaF3, PbTe, Sb2O3, SiO, SiN, Ta2Os, ZnS, ZnSe, ZrO2 and Na3AlF6, and the thickness is 0.5μm to 10μm.

16. The optical filter according to claim 14, characterized in that: A protective layer is also included, and the material of the protective layer is optical resin.

17. The optical filter according to claim 16, characterized in that: The protective layer has a thickness of 10 μm to 30 μm, and is located between the near infrared absorption layer and the anti-reflection layer.

18. The optical filter according to claim 1, characterized in that: The total thickness of the filter is 225 μm to 800 μm.

19. The optical filter according to claim 1, characterized in that: The optical filter has a haze of 0.5% or less.

20. The optical filter according to claim 1, characterized in that The maximum transmittance of the filter for incident light in the wavelength range of 930nm to 950nm is less than 0.01%.

21. The optical filter according to claim 20, characterized in that The maximum transmittance of the filter for incident light in the wavelength range of 930nm to 950nm is less than 0.005%.

22. The optical filter according to claim 1, characterized in that The minimum transmittance of the filter to incident light in the wavelength range of 460nm to 560nm is above 80%.

23. The optical filter according to claim 23, characterized in that: The minimum transmittance of the filter to incident light in the wavelength range of 460nm to 560nm is above 85%.

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

25. The optical filter according to claim 24, characterized in that When incident light irradiates the filter at incident angles of 0 degrees and 30 degrees, respectively, the central wavelength of the passband is shifted, and the shift amplitude is less than 1.4 nm.

26. The optical filter according to claim 24, characterized in that When the incident light irradiates the filter at incident angles of 0 degrees and 35 degrees respectively, the central wavelength of the passband is shifted, and the shift amplitude is less than 1.9 nm.

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