Infrared cut filter with low reflection of high incident visible light and film system design

Abstract

This invention provides an infrared cutoff filter with low reflection of visible light incident at large angles, comprising a substrate, a first film stack, a second film stack, a third film stack, and a fourth film stack. The first film stack is deposited on the lower surface of the substrate, the second film stack is deposited on the surface of the first film stack, the third film stack is deposited on the surface of the second film stack, and the fourth film stack is deposited on the surface of the third film stack. When light is incident on the lens at a large angle, this invention significantly reduces reflection in the blue and blue-green wavelengths, thereby making colors more realistic.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical coating, in particular to a large-angle incident visible light low-reflection infrared cut-off filter and film system design. BACKGROUND

[0002] The current mainstream image taking lens internal structure is mainly composed of a sensor, an infrared filter, a lens group and a protective cover sheet, wherein the infrared filter is a very important core element in the lens assembly, the infrared filter can effectively filter near-infrared light and allow visible light to pass through, so that the image is clearer and the color is more realistic. With the scene angle of the lens becoming larger and larger, the entire image taking assembly becomes thinner and thinner, the distance between the sensor and the infrared filter becomes closer and closer, so that the reflection stray light between the sensor and the filter becomes larger and larger, and the ghosting, halation and red spot phenomenon becomes more and more serious. The measures such as improving the infrared filter spectrum requirement and replacing the blue glass substrate have reached a bottleneck, and the space for improvement is becoming smaller and smaller. The outer surface of the current protective cover sheet is coated with super-hard waterproof film, and the inner surface is coated with ordinary antireflection film. When the inner surface is coated with an ordinary infrared filter film, the color cast, stray light and ghosting problem is obviously improved when the lens takes images in a small-angle scene, and the color of the photographed photo is softer and more natural. However, when the light is incident on the lens at a large angle, the ordinary infrared filter film coated on the inner surface of the cover sheet will have high reflection in the blue and blue-green wave bands, resulting in serious color distortion. SUMMARY

[0003] (I) Technical problem to be solved

[0004] The present application aims to provide a large-angle incident visible light low-reflection infrared cut-off filter, which can reduce the reflection in the blue and blue-green wave bands when the light is incident on the lens at a large angle, thereby making the color more realistic. In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0005] (II) Technical scheme

[0006] A large-angle incident visible light low-reflection infrared cut-off filter, comprising a substrate, a first film stack, a second film stack, a third film stack and a fourth film stack, the first film stack is deposited on the lower surface of the substrate, the second film stack is deposited on the surface of the first film stack, the third film stack is deposited on the surface of the second film stack, and the fourth film stack is deposited on the surface of the third film stack, the film system structure is represented as: SUB|(a0L1a1H1 b1L1……a3H1 b3L1)(c1H2 d1L2……cxH2 dxL2)(e1H3f1L3……exH3fxL3)(j1H4 k1L4……j3H4 k3L4)|Air;

[0007] Wherein (a0L1 a1H1 b1L1 ……a3H1 b3L1) is the first film stack; (c1H2 d1L2 ……cxH2 dxL2) is the second film stack; (e1H3 f1L3 ……exH3 fxL3) is the third film stack, (j1H4 k1L4 ……j3H4 k3L4) is the fourth film stack;

[0008] SUB represents the substrate, Air represents air, H represents the high refractive index material film layer, L represents the low refractive index material film layer; a, b, c, d, e, f, j, k respectively represent the physical thickness of different film layers, x represents the number of times of alternating plating of the second film stack, y represents the number of times of alternating plating of the third film stack, x is in the range of 10-20, y is in the range of 7-20, and x+y is in the range of 17-40.

[0009] Further, the physical thickness of a, b, c, d, e, f, j, and k is in the range of 0-300nm.

[0010] Further, the total number of layers of the second film stack and the third film stack is in the range of 34-80 layers, the refractive index of the high refractive index material film layer H is in the range of 2.0-3.0, and the refractive index of the low refractive index material film layer L is in the range of 1.2-1.6.

[0011] Further, the high refractive index material film layer contains at least one of TiO2, Ta2O5, Ti3O5, Nb2O5, ZrO2, and the low refractive index material film layer contains one or a mixture of two of SiO2, silicon aluminum mixture, MgF2.

[0012] Further, the super-hard anti-reflection film and the waterproof and anti-fingerprint film are sequentially plated on the upper surface of the substrate.

[0013] A film system design structure of a large-angle incident visible light low-reflection infrared cut-off filter,

[0014] (1) In the first film stack (a0L1 a1H1 b1L1 ……a3H1 b3L1), the thickness of the a0L1 film layer is not limited, the thickness of the a2H1 film layer is greater than 80nm, and the thickness of the film layer other than the a0L1 film layer and the a2H1 film layer is less than 80nm;

[0015] (2) In the second film stack (c1H2 d1L2 ……cxH2 dxL2), the physical thickness of the high refractive index material H2 film layer c1, c2, c3, …, cx is in the range of 80-150nm according to the requirement of infrared cut-off wavelength; the physical thickness of the low refractive index material L2 film layer d1, d2, d3, …, dx is in the range of 100-200nm according to the requirement of infrared cut-off wavelength;

[0016] (3) In the third film stack (e1H3 f1L3…exH3 fxL3), the physical thickness e1, e2, e3, …, ex of the high refractive index material H3 film layer is in the range of 80-150 nm according to the requirement of the infrared cutoff wavelength, and the physical thickness f1, f2, f3, …, fx of the low refractive index material L3 film layer is in the range of 100-200 nm according to the requirement of the infrared cutoff wavelength;

[0017] (4) In the fourth film stack (j1H4 k1L4…j3H4 k3L4), the thickness of the j1H4 film layer and the k3L4 film layer is greater than 80 nm, and the thickness of the film layers other than the j1H4 film layer and the k3L4 film layer is less than 80 nm.

[0018] Further, after the thickness of the first film stack is optimized according to product requirements, the reflectivity of visible light between 0 and 40 degrees can be well controlled, and the reflectivity of yellow and red light bands is controlled, the stability of blue and green characteristic peaks is maintained, and the appearance color consistency of products in continuous production is improved; the thickness of the second film stack is optimized according to the requirement of the product infrared cutoff band range, and the cutoff effect of the infrared rear band is controlled; the thickness of the third film stack is optimized according to the requirement of the product infrared cutoff band range, and the cutoff effect of the infrared front band is controlled; after the thickness of the fourth film stack is optimized according to product requirements, the reflectivity of visible light between 0 and 40 degrees can be well controlled, and the number of reflected light ripples is reduced.

[0019] (Three) Beneficial effects

[0020] Compared with the prior art, the present application has obvious advantages and beneficial effects. Specifically, the present application uses TFCalc and Macleod for design optimization, and at an incident angle of 0-40°, a visible light band low reflection, high transmission, infrared band cutoff infrared filter film system is designed, the reflection in the 420-680 nm band is less than 5%, after the upper surface of the substrate is coated with super-hard anti-reflection film and waterproof and anti-fingerprint film, and the lower surface of the substrate is coated with infrared cutoff filter film, the overall average transmittance in the 420-650 nm band is greater than 97%, and the minimum transmittance is greater than 93%, thereby making the color more realistic. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a film system structure diagram of the present application;

[0022] Figure 2 is a transmittance spectrum diagram of example one;

[0023] Figure 3 is a transmittance spectrum diagram of example two;

[0024] Figure 4 is a transmittance spectrum diagram of example three.

[0025] BRIEF DESCRIPTION OF DRAWINGS

[0026] 1, substrate 2, first film stack 3, second film stack

[0027] 4, third film stack 5, fourth film stack 6, superhard anti-reflective film

[0028] 7, waterproof and anti-fingerprint film DETAILED DESCRIPTION

[0029] Embodiments of the present application are described in detail below with reference to the attached drawing figures, wherein the same or like reference numerals and characters throughout the figures denote the same or like elements or components. The embodiments described below are exemplary and are intended to be illustrative of the present application and are not to be construed as limiting the present application.

[0030] The present application is further described below in conjunction with the accompanying drawings and the detailed description.

[0031] Referring to Figure 1 The drawing shows an infrared cut-off filter with low reflection of visible light at large incidence angle, which comprises a substrate 1, a first film stack 2, a second film stack 3, a third film stack 4 and a fourth film stack 5. The first film stack 2 is deposited on the lower surface of the substrate 1, the second film stack 3 is deposited on the surface of the first film stack 2, the third film stack 4 is deposited on the surface of the second film stack 3, and the fourth film stack 5 is deposited on the surface of the third film stack 3. The film system structure is represented as: SUB|(a0L1 a1H1 b1L1……a3H1 b3L1)(c1H2d1L2……cxH2 dxL2)(e1H3 f1L3……exH3 fxL3)(j1H4 k1L4……j3H4 k3L4)|Air; wherein (a0L1 a1H1 b1L1……a3H1 b3L1) is the first film stack 2, (c1H2d1L2……cxH2 dxL2) is the second film stack 3, (e1H3 f1L3……exH3 fxL3) is the third film stack 4, and (j1H4 k1L4……j3H4 k3L4) is the fourth film stack 5; SUB represents the substrate 1, Air represents air, H represents a high refractive index material film layer, and L represents a low refractive index material film layer; a, b, c, d, e, f, j, and k respectively represent the physical thickness of different film layers, x represents the number of times of alternating film deposition of the second film stack, and y represents the number of times of alternating film deposition of the third film stack; x is in the range of 10-20, y is in the range of 7-20, and x+y is in the range of 17-40.

[0032] The physical thickness of a, b, c, d, e, f, j, and k ranges between 0-300 nm; the total number of layers of the second film stack and the third film stack ranges between 34-80 layers; the refractive index of the high refractive index material film layer H is between 2.0-3.0; the refractive index of the low refractive index material film layer L is between 1.2-1.6; the high refractive index material film layer contains at least one of TiO2, Ta2O5, Ti3O5, Nb2O5, and ZrO2; the low refractive index material film layer contains one or a mixture of two of SiO2, a silicon-aluminum mixture, and MgF2; the substrate can be made of a visible light-transmitting glass, resin, crystal, or sapphire material; and the upper surface of the substrate is sequentially coated with the super-hard anti-reflection film 6 and the waterproof and anti-fingerprint film 7.

[0033] A film system design structure of a large-angle incident visible light low-reflection infrared cut-off filter,

[0034] (1) In the first film stack 2 (a0L1 a1H1 b1L1 …… a3H1 b3L1), the thickness of the a0L1 film layer is not limited, the thickness of the a2H1 film layer is greater than 80 nm, and the thickness of the film layers other than the a0L1 film layer and the a2H1 film layer is less than 80 nm.

[0035] (2) In the second film stack 3 (c1H2 d1L2 …… cxH2 dxL2), the physical thickness of the high refractive index material H2 film layer c1, c2, c3, ……, cx ranges between 80-150 nm according to the infrared cut-off wavelength requirement; the physical thickness of the low refractive index material L2 film layer d1, d2, d3, ……, dx ranges between 100-200 nm according to the infrared cut-off wavelength requirement.

[0036] (3) In the third film stack 4 (e1H3 f1L3 …… exH3 fxL3), the physical thickness of the high refractive index material H3 film layer e1, e2, e3, ……, ex ranges between 80-150 nm according to the infrared cut-off wavelength requirement; the physical thickness of the low refractive index material L3 film layer f1, f2, f3, ……, fx ranges between 100-200 nm according to the infrared cut-off wavelength requirement.

[0037] (4) In the fourth film stack 5 (j1H4 k1L4 …… j3H4 k3L4), the thickness of the j1H4 film layer and the k3L4 film layer is greater than 80 nm, and the thickness of the film layers other than the j1H4 film layer and the k3L4 film layer is less than 80 nm.

[0038] Furthermore, after optimizing the thickness of the first membrane stack 2 according to product requirements, it can effectively control the reflectivity of visible light between 0 and 40 degrees, and control the reflectivity of the yellow and red light bands, while maintaining the stability of the blue and green characteristic peaks, thereby improving the consistency of the appearance color of products produced continuously. After optimizing the thickness of the second membrane stack 3 according to the product's infrared cutoff band requirements, it controls the cutoff effect of the infrared back band. After optimizing the thickness of the third membrane stack 4 according to the product's infrared cutoff band requirements, it controls the cutoff effect of the infrared front band. After optimizing the thickness of the fourth membrane stack 5 according to product requirements, it can effectively control the reflectivity of visible light between 0 and 40 degrees, reducing the number of ripples in the reflected light.

[0039] Example 1:

[0040] Using ordinary optical glass as a substrate, the upper surface of the substrate is coated with an ultra-hard antireflective film and a waterproof and fingerprint-resistant film. The lower surface of the substrate is coated with the filter film system designed in this invention, which is composed of alternating layers of high-refractive-index material Ta2O5 and low-refractive-index material SiO2. The high-refractive-index material Ta2O5 has a refractive index of 2.1825 at 546 nm, and the low-refractive-index material SiO2 has a refractive index of 1.4647 at 539 nm. The physical thickness of the first layer to the last layer of this film system is designed as follows:

[0041] First membrane stack: 0nm (SiO2), 15.54nm (Ta2O5), 36.02nm (SiO2), 139.1nm (Ta2O5), 50.97nm (SiO2), 22.36nm (Ta2O5), 55.9nm (SiO2)

[0042] Second membrane stack: 130.21nm (Ta2O5), 187.89nm (SiO2), 122.68nm (Ta2O5), 187.96nm (SiO2), 122.88nm (Ta2O5), 188.67nm (SiO2), 120.44nm (Ta2O5), 182.83nm (SiO2), 116.12nm (Ta2O5), 174.35nm (SiO2). O2), 112.26nm (Ta2O5), 171.79nm (SiO2), 113.68nm (Ta2O5), 172.52nm (SiO2), 114.81nm (Ta2 O5), 174.2nm (SiO2), 113.43nm (Ta2O5), 171.79nm (SiO2), 109.13nm (Ta2O5), 162.47nm (SiO2)

[0043] Third membrane stack: 106.53nm (Ta2O5), 161.72nm (SiO2), 102.48nm (Ta2O5), 159.52nm (SiO2), 104.51nm (Ta2O5), 158.44nm (SiO2), 102.83nm (Ta2O5), 161.81nm (SiO2), 101.57nm (Ta2O5), 159.68nm (SiO2), 102.69nm (Ta2O5), 160.4nm (SiO2), 102.07nm (Ta2O5), 166.34nm (SiO2)

[0044] Fourth membrane stack: 126.98nm (Ta2O5), 37.54nm (SiO2), 39.91nm (Ta2O5), 21.53nm (SiO2), 62.27nm (Ta2O5), 89.5nm (SiO2)

[0045] The similarities between this embodiment and other conventional infrared filters are that the second and third film stacks are basically the same as the film systems of conventional infrared filters; the differences are that the special combination of thick and thin layers in the first and fourth film stacks can effectively achieve low reflection of visible light at a large angle without affecting the infrared cutoff effect.

[0046] The coating was applied using the OTFC-1550 optical coating machine. Actual measured spectra are as follows: Figure 2 As shown.

[0047] like Figure 2 In the graph, the horizontal axis represents the wavelength of light, and the vertical axis represents the transmittance of the filter. The spectral curves were obtained from measurements taken at incident angles of 0°, 30°, and 40°. Figure 2 It can be seen that in the visible light band of 420-650nm, its minimum transmittance is higher than 93% and its average transmittance is higher than 97%, while in the infrared band of 800-1000nm, its cutoff transmittance is less than 1%.

[0048] Example 2:

[0049] Using ordinary optical glass as a substrate, the upper surface of the substrate is coated with an ultra-hard antireflective film and a waterproof and fingerprint-resistant film. The lower surface of the substrate is coated with the filter film system designed in this invention, which is composed of alternating layers of high-refractive-index material Ta2O5 and low-refractive-index material SiO2. The high-refractive-index material Ta2O5 has a refractive index of 2.1825 at 546 nm, and the low-refractive-index material SiO2 has a refractive index of 1.4647 at 539 nm. The physical thickness of the first layer to the last layer of this film system is designed as follows:

[0050] First membrane stack: 11.1nm (SiO2), 14.37nm (Ta2O5), 37.18nm (SiO2), 134.05nm (Ta2O5), 64.3nm (SiO2), 11.66nm (Ta2O5), 77.62nm (SiO2)

[0051] Second membrane stack: 125.12nm (Ta2O5), 185.71nm (SiO2), 123.41nm (Ta2O5), 189.47nm (SiO2), 122.64nm (Ta2O5), 185.49nm (SiO2), 121.16nm (Ta2O5), 183.84nm (SiO2), 120.5nm (Ta2O5), 181.02nm (SiO2). O2), 116.3nm (Ta2O5), 172.23nm (SiO2), 108.52nm (Ta2O5), 164.3nm (SiO2), 112.5nm (Ta2O5 ), 176.05nm(SiO2), 117.35nm(Ta2O5), 172.47nm(SiO2), 105.86nm(Ta2O5), 150.68nm(SiO2)

[0052] Third membrane stack: 99.38nm (Ta2O5), 145.32nm (SiO2), 94.81nm (Ta2O5), 144.71nm (SiO2), 94.34nm (Ta2O5), 143.52nm (SiO2), 93.31nm (Ta2O5), 142.94nm (SiO2), 92.16nm (Ta2O5), 142.05nm (SiO2), 95.8nm (Ta2O5), 145.06nm (SiO2), 94.22nm (Ta2O5), 150.69nm (SiO2)

[0053] Fourth membrane stack: 118.8nm (Ta2O5), 40.72nm (SiO2), 36.64nm (Ta2O5), 20.78nm (SiO2), 58.64nm (Ta2O5), 87.59nm (SiO2).

[0054] The similarities between this embodiment and other conventional infrared filters are that the second and third film stacks are basically the same as the film systems of conventional infrared filters; the differences are that the special combination of thick and thin layers in the first and fourth film stacks can effectively achieve low reflection of visible light at a large angle without affecting the infrared cutoff effect.

[0055] The coating was applied using the OTFC-1550 optical coating machine. Actual measured spectra are as follows: Figure 3 As shown.

[0056] like Figure 3 In the graph, the horizontal axis represents the wavelength of light, and the vertical axis represents the transmittance of the filter. The spectral curves were obtained from measurements taken at incident angles of 0°, 30°, and 40°. Figure 3 It can be seen that in the visible light band of 420-650nm, its minimum transmittance is higher than 93% and its average transmittance is higher than 97%, while in the infrared band of 800-1000nm, its cutoff transmittance is less than 1%.

[0057] Example 3:

[0058] Using ordinary optical glass as a substrate, the upper surface is coated with an ultra-hard anti-reflective film and a waterproof and fingerprint-resistant film, while the lower surface is coated with the filter film system designed in this invention. This system is composed of alternating layers of high-refractive-index material ZrO2 and low-refractive-index material "silicon-aluminum mixture." The high-refractive-index ZrO2 layer has a refractive index of 2.192 at 600 nm, and the low-refractive-index silicon-aluminum mixture layer has a refractive index of 1.4706 at 540 nm. The physical thickness of the first to last layers of this film system is designed as follows:

[0059] First membrane stack: 22.5nm (SiO2), 15.1nm (Ta2O5), 36.96nm (SiO2), 138.59nm (Ta2O5), 55.19nm (SiO2), 19.04nm (Ta2O5), 63.61nm (SiO2).

[0060] Second membrane stack: 131.21nm (Ta2O5), 188.7nm (SiO2), 125.05nm (Ta2O5), 190.8nm (SiO2), 126.06nm (Ta2O5), 189.45nm (SiO2), 124.9nm (Ta2O5), 189.11nm (SiO2), 124.63nm (Ta2O5), 185.65nm (SiO2). 2), 120.85nm(Ta2O5), 177.57nm(SiO2), 113.54nm(Ta2O5), 168.91nm(SiO2), 114.84nm(Ta2 O5), 173.9nm (SiO2), 116.76nm (Ta2O5), 171.72nm (SiO2), 110.5nm (Ta2O5), 159.01nm (SiO2)

[0061] Third membrane stack: 103.36nm (Ta2O5), 152.17nm (SiO2), 100.29nm (Ta2O5), 148.43nm (SiO2), 99.74nm (Ta2O5), 146.56nm (SiO2), 98.69nm (Ta2O5), 147.79nm (SiO2), 98.36nm (Ta2O5), 146.97nm (SiO2), 98.81nm (Ta2O5), 150.1nm (SiO2), 99.06nm (Ta2O5), 153.38nm (SiO2)

[0062] Fourth membrane stack: 118.86nm (Ta2O5), 47.08nm (SiO2), 26.44nm (Ta2O5), 24.09nm (SiO2), 87.73nm (Ta2O5), 82.4nm (SiO2)

[0063] The similarities between this embodiment and other conventional infrared filters are that the second and third film stacks are basically the same as the film systems of conventional infrared filters; the differences are that the special combination of thick and thin layers in the first and fourth film stacks can effectively achieve low reflection of visible light at a large angle without affecting the infrared cutoff effect.

[0064] The coating was applied using the OTFC-1550 optical coating machine. Actual measured spectra are as follows: Figure 4 As shown.

[0065] like Figure 4 In the diagram, the horizontal axis represents the wavelength of light, and the vertical axis represents the transmittance of the filter. The spectral curves are obtained from measurements at incident angles of 0°, 30°, and 40°. Figure 4 It can be seen that in the visible light band of 420-650nm, its minimum transmittance is higher than 93% and its average transmittance is higher than 97%, while in the infrared band of 800-1000nm, its cutoff transmittance is less than 1%.

[0066] This invention forms an infrared cut-off filter that acts as a cover by depositing specific film layers in a specific order on the surface of a substrate. When light enters the lens at a large angle, the reflection in the blue light band and blue-green band is greatly reduced, thereby making the colors more realistic.

[0067] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A low-reflection infrared cutoff filter for large-angle incident visible light, characterized in that: The system includes a substrate, a first film stack, a second film stack, a third film stack, and a fourth film stack. The first film stack is deposited on the lower surface of the substrate, the second film stack is deposited on the surface of the first film stack, the third film stack is deposited on the surface of the second film stack, and the fourth film stack is deposited on the surface of the third film stack. The film system structure is represented as: SUB |(a0L1 a1H1 b1L1……a3H1 b3L1)(c1H2 d1L2……cxH2dxL2)(e1H3 f1L3……eyH3 fyL3)(j1H4 k1L4……j3H4 k3L4)| Air; Among them, (a0L1 a1H1 b1L1……a3H1 b3L1) is the first film stack, with the thickness of the a0L1 film layer being 0-22.5nm, the thickness of the a2H1 film layer being 80-139.1nm, and the thickness of all film layers except the a0L1 and a2H1 films being less than 80nm; (c1H2d1L2……cxH2 dxL2) is the second film stack, with the physical thicknesses of the high-refractive-index material H2 film layer (c1, c2, c3, ..., cx) ranging from 80-150nm; and the physical thicknesses of the low-refractive-index material L2 film layer (d1, d2, d3, ..., dx) ranging from 100-200nm; (e1H3 f1L3……exH3 fxL3) The third layer consists of high-refractive-index material H3 with physical thicknesses e1, e2, e3, ..., ex ranging from 80 to 150 nm, and low-refractive-index material L3 with physical thicknesses f1, f2, f3, ..., fx ranging from 100 to 200 nm. The fourth layer consists of (j1H4 k1L4 ... j3H4 k3L4) with thicknesses of j1H4 ranging from 80 to 126.98 nm and k3L4 ranging from 80 to 89.5 nm. The thicknesses of all layers except j1H4 and k3L4 are less than 80 nm. SUB represents the substrate, Air represents air, H represents a high refractive index material film layer, and L represents a low refractive index material film layer; a, b, c, d, e, f, j, and k represent the physical thicknesses of different film layers, x represents the number of times the second film stack is alternately coated, y represents the number of times the third film stack is alternately coated, x ranges from 10 to 20, y ranges from 7 to 20, and x+y ranges from 17 to 40. The physical thicknesses of a, b, c, d, e, f, j, and k range from 0 to 300 nm. The total number of layers in the second and third film stacks is between 34 and 80, the refractive index of the high refractive index material layer H is between 2.0 and 3.0, and the refractive index of the low refractive index material layer L is between 1.2 and 1.

6.

2. The infrared cutoff filter with low reflection for large-angle incident visible light according to claim 1, characterized in that: The high refractive index material film contains at least one of TiO2, Ta2O5, Ti3O5, Nb2O5, and ZrO2, and the low refractive index material film contains one or a mixture of two of SiO2, a silicon-aluminum mixture, and MgF2.

3. The infrared cutoff filter with low reflection for large-angle incident visible light according to claim 1, characterized in that: The substrate is sequentially coated with an ultra-hard anti-reflective film and a waterproof and fingerprint-resistant film.

4. The film system design structure of the infrared cut-off filter with low reflection of visible light incident at a large angle according to claim 1, characterized in that: (1) In the first membrane stack (a0L1 a1H1 b1L1……a3H1 b3L1), the thickness of the a0L1 membrane is 0-22.5nm, the thickness of the a2H1 membrane is 80-139.1nm, and the thickness of the membranes other than the a0L1 membrane and the a2H1 membrane is less than 80nm. (2) In the second film stack (c1H2 d1L2……cxH2 dxL2), the physical thicknesses of the high refractive index material H2 film layer (c1, c2, c3, ..., cx) range from 80 to 150 nm; the physical thicknesses of the low refractive index material L2 film layer (d1, d2, d3, ..., dx) range from 100 to 200 nm. (3) In the third film stack (e1H3 f1L3……exH3 fxL3), the physical thicknesses of the high refractive index material H3 film layer e1, e2, e3, ..., ex range from 80 to 150 nm; the physical thicknesses of the low refractive index material L3 film layer f1, f2, f3, ..., fx range from 100 to 200 nm. (4) In the fourth membrane stack (j1H4 k1L4……j3H4 k3L4), the thickness of the j1H4 membrane is 80-126.98nm, the thickness of the k3L4 membrane is 80-89.5nm, and the thickness of the membranes other than the j1H4 membrane and the k3L4 membrane is less than 80nm.

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