Infrared optical lens and infrared optical equipment

Abstract

The present invention discloses an infrared optical lens and infrared optical equipment, wherein the infrared optical lens comprises a first lens, a second lens, a third lens and a fourth lens from the object side to the image side, the object side surface and the image side surface of the first lens, the second lens, the third lens and the fourth lens are all aspherical surfaces, the effective focal length f1 of the first lens and the total effective focal length f of the infrared optical lens satisfy 1.2<f1 / f<1.5, and 3.69mm≤f≤3.70mm, and the wavelength range of the light source is 812nm~832nm. The infrared optical lens and infrared optical equipment in the present invention can improve the resolution of the lens, reduce optical distortion, and ensure relative illumination by optimizing parameters such as lens thickness, focal length, and effective aperture, and can be widely used in optical equipment in the infrared band.

Description

Technical Field

[0001] The invention belongs to the technical field of optical lenses, and in particular relates to an infrared optical lens and infrared optical equipment. Background Art

[0002] In recent years, with the rapid development of depth recognition technology, three-dimensional depth cameras have been more and more widely used in AR enhancement technology. As one of the mainstream directions of depth recognition technology, the structured light solution performs depth recognition in the following way: a special image (coded pattern or dot matrix image) is projected onto the object by a projection lens module; an imaging receiving module is used to receive the image information reflected from the object; and the depth information of the object is obtained by processing the received image information through the back-end algorithm. As one of the core components of structured light depth recognition technology, the optical performance of the imaging receiving lens will greatly affect the accuracy of depth recognition.

[0003] Optical distortion and resolution are two important indicators for evaluating optical performance. The optical lenses in the prior art are still unable to effectively guarantee optical distortion and resolution in the infrared band.

[0004] Therefore, in view of the above technical problems, it is necessary to provide an infrared optical lens and an infrared optical device. Summary of the invention

[0005] The purpose of the present invention is to provide an infrared optical lens and an infrared optical device.

[0006] In order to achieve the above purpose, the technical solution provided by an embodiment of the present invention is as follows:

[0007] An infrared optical lens, comprising a first lens, a second lens, a third lens and a fourth lens from the object side to the image side, wherein the object side surface and the image side surface of the first lens, the second lens, the third lens and the fourth lens are all aspherical surfaces, wherein:

[0008] The first lens has positive refractive power, and its object side surface is convex at the optical axis;

[0009] The second lens has positive or negative optical power, and its object side optical axis is concave, and its image side optical axis is convex;

[0010] The third lens has positive refractive power, and its object side optical axis is concave, and its image side optical axis is convex;

[0011] The fourth lens has negative optical power, and its object side surface is convex at the optical axis, and has at least one concave surface off the axis on the object side surface, and its image side surface is concave at the optical axis, and has at least one convex surface off the axis on the image side surface;

[0012] The effective focal length f1 of the first lens and the total effective focal length f of the infrared optical lens satisfy 1.2<f1 / f<1.5, and 3.69mm≤f≤3.70mm, and the wavelength range of the light source is 812nm~832nm.

[0013] In one embodiment, the effective focal length f1 of the first lens, the effective focal length f2 of the second lens, the effective focal length f3 of the third lens and the total effective focal length f of the infrared optical lens satisfy 1.5<|f / f1|+|f / f2|+|f / f3|<2.1.

[0014] In one embodiment, the radius of curvature R1 of the object side surface of the first lens and the total effective focal length f of the infrared optical lens satisfy 0.1<R1 / f<0.6.

[0015] In one embodiment, the sum of the center thicknesses ∑CT of the first lens, the second lens, the third lens and the fourth lens on the optical axis and the spacing distance TTL from the object side surface of the first lens to the imaging surface of the infrared optical lens on the optical axis satisfy 0.45<∑CT / TTL<0.51.

[0016] In one embodiment, an axial distance SAG11 from the intersection of the object side surface of the first lens and the optical axis to the effective half-aperture vertex of the object side surface of the first lens and a center thickness CT1 of the first lens on the optical axis satisfy 0.35<SAG11 / CT1<0.45.

[0017] In one embodiment, the maximum effective semi-aperture DT42 of the image side surface of the fourth lens and half the diagonal length ImgH of the effective pixel area of ​​the photosensitive element on the imaging surface of the infrared optical lens satisfy 0.68<DT42 / ImgH<0.72.

[0018] In one embodiment, the total effective focal length f of the infrared optical lens and the entrance pupil diameter EPD of the infrared optical lens satisfy 1.8<f / EPD<1.9.

[0019] In one embodiment, the distance TTL from the center of the object side surface of the first lens to the imaging surface of the infrared optical lens on the optical axis and the half of the diagonal length of the effective pixel area on the imaging surface of the infrared optical lens ImgH meet 1.7 <TTL / ImgH<1.85。

[0020] In one embodiment, in the infrared optical lens:

[0021] The effective aperture of the first lens on the object side is 0.97mm to 0.98mm, and the effective aperture of the image side is 0.99mm to 1.05mm;

[0022] The effective aperture of the second lens on the object side is 0.95mm to 1.04mm, and the effective aperture of the image side is 1.11mm to 1.16mm;

[0023] The effective aperture of the third lens on the object side is 1.14mm to 1.19mm, and the effective aperture of the image side is 1.45mm to 1.57mm;

[0024] The effective aperture of the fourth lens on the object side is 2.05 mm to 2.14 mm, and the effective aperture of the fourth lens on the image side is 2.52 mm to 2.61 mm.

[0025] In one embodiment, the infrared optical lens further includes:

[0026] A filter, located on the image side of the fourth lens;

[0027] A lens barrel, used for encapsulating the first lens, the second lens, the third lens and the fourth lens;

[0028] A plurality of spacer rings are packaged between the first lens and the second lens, and / or the second lens and the third lens, and / or the third lens and the fourth lens.

[0029] The technical solution provided by an embodiment of the present invention is as follows:

[0030] An infrared optical device is provided with at least one infrared optical lens as described above.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] The infrared optical lens and infrared optical device of the present invention can improve the resolution of the lens, reduce optical distortion, and ensure relative illumination by optimizing parameters such as lens thickness, focal length, and effective aperture, and can be widely used in optical devices in the infrared band. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 It is a schematic diagram of the structure of the infrared optical lens of the present invention;

[0035] Figure 2 It is a schematic diagram of light transmission of the infrared optical lens of the present invention;

[0036] Figure 3is a resolution curve diagram of the optical lens in the first embodiment of the present invention;

[0037] Figure 4 is a distortion curve diagram of the optical lens in the first embodiment of the present invention;

[0038] Figure 5 It is a relative illumination curve diagram of the optical lens in the first embodiment of the present invention. DETAILED DESCRIPTION

[0039] The present invention will be described in detail below in conjunction with the various embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional changes made by a person skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0040] Ginseng Figure 1 , Figure 2 As shown, the present invention discloses an infrared optical lens, which includes a first lens 10, a second lens 20, a third lens 30 and a fourth lens 40 from the object side to the image side, and the object side surface and the image side surface of the first lens 10, the second lens 20, the third lens 30 and the fourth lens 40 are all aspherical surfaces, wherein:

[0041] The first lens 10 has positive refractive power, and its object side surface is convex at the optical axis;

[0042] The second lens 20 has positive or negative refractive power, and its object side optical axis is concave, and its image side optical axis is convex;

[0043] The third lens 30 has positive refractive power, and its object side optical axis is concave, and its image side optical axis is convex;

[0044] The fourth lens 40 has negative refractive power, with a convex surface on the object side at the optical axis and at least one concave surface on the object side off-axis, a concave surface on the image side at the optical axis and at least one convex surface on the image side off-axis.

[0045] Furthermore, the infrared optical lens also includes:

[0046] A filter 50, located on the image side of the fourth lens 40;

[0047] The lens barrel 60 is used to encapsulate the first lens 10, the second lens 20, the third lens 30 and the fourth lens 40;

[0048] A plurality of spacer rings 70 are packaged between the first lens and the second lens, between the second lens and the third lens, and between the third lens and the fourth lens.

[0049] The effective focal length f1 of the first lens 10 in the present invention and the total effective focal length f of the infrared optical lens satisfy 1.2<f1 / f<1.5, and 3.69mm≤f≤3.70mm, and the wavelength range of the light source is 812nm~832nm. Reasonable configuration of the effective focal length of the first lens can effectively correct the spherical aberration of the lens and ensure high imaging quality.

[0050] Preferably, the effective focal length f1 of the first lens, the effective focal length f2 of the second lens, the effective focal length f3 of the third lens and the total effective focal length f of the infrared optical lens satisfy 1.5<|f / f1|+|f / f2|+|f / f3|<2.1.

[0051] Preferably, the object side curvature radius R1 of the first lens and the total effective focal length f of the infrared optical lens satisfy 0.1<R1 / f<0.6, which can better correct the aberration of the system's off-axis field of view and ensure high resolution in the central field of view; at the same time, it is conducive to obtaining a larger lens aperture.

[0052] Preferably, the sum of the center thicknesses ∑CT of the first lens, the second lens, the third lens and the fourth lens on the optical axis and the spacing distance TTL from the object side of the first lens to the imaging surface of the infrared optical lens on the optical axis satisfy 0.45<∑CT / TTL<0.51, which can better correct the aberration of the off-axis field of view area of ​​the imaging system and is conducive to making each lens have better processability.

[0053] Preferably, an axial distance SAG11 from the intersection of the object side surface of the first lens and the optical axis to the effective semi-aperture vertex of the object side surface of the first lens and a center thickness CT1 of the first lens on the optical axis satisfy 0.35<SAG11 / CT1<0.45.

[0054] Preferably, the maximum effective semi-aperture DT42 of the image side surface of the fourth lens and half the diagonal length ImgH of the effective pixel area of ​​the photosensitive element on the imaging surface of the infrared optical lens satisfy 0.68<DT42 / ImgH<0.72, which is conducive to meeting the miniaturization requirements and ensuring a higher relative brightness at the same time.

[0055] Preferably, the total effective focal length f of the infrared optical lens and the entrance pupil diameter EPD of the infrared optical lens satisfy 1.8<f / EPD<1.9.

[0056] Preferably, the distance TTL from the center of the object side surface of the first lens to the imaging surface of the infrared optical lens on the optical axis and the half of the diagonal length of the effective pixel area on the imaging surface of the infrared optical lens ImgH satisfy 1.7 <TTL / ImgH<1.85。

[0057] In the present invention, the effective aperture of the object side of the first lens is 0.97mm-0.98mm, and the effective aperture of the image side is 0.99mm-1.05mm; the effective aperture of the object side of the second lens is 0.95mm-1.04mm, and the effective aperture of the image side is 1.11mm-1.16mm; the effective aperture of the object side of the third lens is 1.14mm-1.19mm, and the effective aperture of the image side is 1.45mm-1.57mm; the effective aperture of the object side of the fourth lens is 2.05mm-2.14mm, and the effective aperture of the image side is 2.52mm-2.61mm.

[0058] Preferably, the effective aperture of the objective side of the first lens is 0.978mm-0.980mm, and the effective aperture of the image side is 1.001mm-1.032mm; the effective aperture of the objective side of the second lens is 0.999mm-1.030mm, and the effective aperture of the image side is 1.119mm-1.152mm; the effective aperture of the objective side of the third lens is 1.140mm-1.181mm, and the effective aperture of the image side is 1.465mm-1.568mm; the effective aperture of the objective side of the fourth lens is 2.067mm-2.137mm, and the effective aperture of the image side is 2.520mm-2.601mm.

[0059] The present invention improves resolution and reduces distortion by controlling the ratio of the center thickness to the total thickness of each lens and reasonably allocating the focal length ratio of each lens.

[0060] The present invention is further described below in conjunction with specific embodiments.

[0061] Embodiment 1:

[0062] In this embodiment, the total effective focal length of the infrared optical lens is f=3.697 mm, and the first lens 10, the second lens 20, the third lens 30 and the fourth lens 40 are all resin lenses, the center is a lens, and the edges are corroded and matted. The material, refractive index and effective focal length are as follows:

[0063] The first lens 10 is made of E48R, has a refractive index of 1.531, an effective focal length f1=5.190 mm, an effective aperture on the object side of 0.979 mm, and an effective aperture on the image side of 1.008 mm;

[0064] The second lens 20 is made of EP5000, has a refractive index of 1.635, an effective focal length f2=23.898 mm, an effective aperture of the object side is 1.000 mm, and an effective aperture of the image side is 1.124 mm;

[0065] The third lens 30 is made of E48R, has a refractive index of 1.531, an effective focal length f3=3.112 mm, an effective aperture on the object side is 1.145 mm, and an effective aperture on the image side is 1.567 mm;

[0066] The fourth lens 40 is made of E48R, has a refractive index of 1.531, an effective focal length f4=-4.231 mm, an effective aperture on the object side is 2.078 mm, and an effective aperture on the image side is 2.541 mm.

[0067] The ratio of the effective focal length f1 of the first lens 10 to the total effective focal length f of the infrared optical lens is f1 / f=1.404;

[0068] The effective focal length f1 of the first lens, the effective focal length f2 of the second lens, the effective focal length f3 of the third lens and the total effective focal length f of the infrared optical lens satisfy |f / f1|+|f / f2|+|f / f3|=2.055.

[0069] The object side curvature radius of the first lens is R1=0.713 mm, and its ratio to the total effective focal length f of the infrared optical lens is R1 / f=0.193.

[0070] The sum of the center thicknesses of the first lens, the second lens, the third lens and the fourth lens on the optical axis ∑CT=2.754 mm, the spacing distance between the object side surface of the first lens and the imaging surface of the infrared optical lens on the optical axis TTL=5.495 mm, ∑CT / TTL=0.501.

[0071] The axial distance SAG11 from the intersection of the object side surface of the first lens and the optical axis to the effective half-aperture vertex of the object side surface of the first lens is 0.273 mm, the center thickness CT1 of the first lens on the optical axis is 0.713 mm, and SAG11 / CT1 is 0.383.

[0072] The maximum effective semi-aperture DT42 of the image side of the fourth lens is 2.078 mm, half of the diagonal length of the effective pixel area of ​​the photosensitive element on the imaging surface of the infrared optical lens is ImgH=3.000 mm, and DT42 / ImgH=0.693.

[0073] The total effective focal length of the infrared optical lens is f=3.697 mm, the entrance pupil diameter EPD of the infrared optical lens is EPD=1.957 mm, and f / EPD=1.890.

[0074] The distance from the center of the object side surface of the first lens to the imaging surface of the infrared optical lens on the optical axis is TTL=5.495 mm, and its ratio to half the diagonal length ImgH of the effective pixel area on the imaging surface of the infrared optical lens is TTL / ImgH=1.832.

[0075] The surface of each lens is aspherical and satisfies the aspherical formula:

[0076]

[0077] Among them, Z is the aspheric curve, C=1 / r (r is the paraxial spherical radius), Y is the radius of curvature, K is the cone constant (quadratic surface constant), and a, b, c, d, e... are high-order coefficients (4th order, 6th order, 8th order, 10th order, 12th order...).

[0078] The object side surface and image side surface of the first lens 10 are S1 and S2 respectively, the object side surface and image side surface of the second lens 20 are S3 and S4 respectively, the object side surface and image side surface of the third lens 30 are S5 and S6 respectively, the object side surface and image side surface of the fourth lens 40 are S7 and S8 respectively, and S1-SAG to S8-SAG are the sag heights of each surface (at 0.2mm, 0.4mm, 0.6mm, and 0.8mm). The specific surface parameters are shown in Tables 1 and 2.

[0079] Table 1: Lens surface parameters Table 1

[0080]

[0081]

[0082] Table 2: Lens surface parameters Table 2

[0083] S1-SAG S2-SAG S3-SAG S4-SAG 0.2 0.01053133471831 0.00358468367088 -0.0029627972579 -0.0041806080557 0.4 0.0425848711431 0.01401446798168 -0.0142510824849 -0.0306896222098 0.6 0.09762709732581 0.02974991466551 -0.0430703504256 -0.107575797538 0.8 0.17821387441138 0.04399101030559 -0.1127596259901 -0.2651009697167 S5-SAG S6-SAG S7-SAG S8-SAG 0.2 -0.0121891159602 -0.0194555166513 0.02641705079163 0.08433036546007 0.4 -0.0770284860696 -0.168859781545 0.14796709693557 0.36194696248054 0.6 -0.2165234475881 -0.4596294670822 0.17868469806762 0.49149316737987 0.8 -0.4897369094091 -0.9396372914827 -0.0255041738777 0.13647018150703

[0084] Ginseng Figure 3 The graph of image height (Real Image Height)-resolution (MTF) in this embodiment is shown, and from top to bottom, they are the resolution curves of the meridian direction (S) and arc loss direction (T) when the spatial frequency is 0%, the meridian direction (S) and arc loss direction (T) when the spatial frequency is 33%, the meridian direction (S) and arc loss direction (T) when the spatial frequency is 66%, and the meridian direction (S) and arc loss direction (T) when the spatial frequency is 132%. It can be seen that the infrared optical lens in this embodiment has good resolution at high frequencies, and the center area to the peripheral area is relatively smooth.

[0085] Ginseng Figure 4 The distortion curve in this embodiment is shown in FIG. 1 , and it can be seen that the distortion of the infrared optical lens in this embodiment is relatively small, less than 1.7%. Figure 5 The graph shown is a relative field height (Relative Field Height)-relative illumination (Relative Illumination) curve in this embodiment. It can be seen that the relative illumination of the infrared optical lens in this embodiment is greater than 32%.

[0086] Embodiment 2:

[0087] In this embodiment, the total effective focal length of the infrared optical lens is f=3.693 mm, and the first lens, the second lens, the third lens and the fourth lens are all resin lenses, the center is a lens, and the edges are corroded and matte treated. The material, refractive index and effective focal length are as follows:

[0088] The first lens is made of E48R, with a refractive index of 1.531, an effective focal length of f1 = 4.565mm, an effective aperture of 0.979mm on the object side, and an effective aperture of 1.027mm on the image side;

[0089] The second lens is made of EP5000, with a refractive index of 1.635, an effective focal length of f2 = -115.52mm, an effective aperture of 1.026mm on the object side, and an effective aperture of 1.144mm on the image side;

[0090] The third lens is made of E48R, with a refractive index of 1.531, an effective focal length of f3 = 4.133mm, an effective aperture of 1.169mm on the object side, and an effective aperture of 1.472mm on the image side;

[0091] The fourth lens is made of E48R, has a refractive index of 1.531, an effective focal length of f4=-5.416mm, an effective aperture on the object side is 2.101mm, and an effective aperture on the image side is 2.554mm.

[0092] The ratio of the effective focal length f1 of the first lens to the total effective focal length f of the infrared optical lens is f1 / f=1.236;

[0093] The effective focal length f1 of the first lens, the effective focal length f2 of the second lens, the effective focal length f3 of the third lens and the total effective focal length f of the infrared optical lens satisfy |f / f1|+|f / f2|+|f / f3|=1.670.

[0094] The object side curvature radius of the first lens is R1=1.751 mm, and its ratio to the total effective focal length f of the infrared optical lens is R1 / f=0.474.

[0095] The sum of the center thicknesses of the first lens, the second lens, the third lens and the fourth lens on the optical axis ∑CT=2.537 mm, the spacing distance between the object side surface of the first lens and the imaging surface of the infrared optical lens on the optical axis TTL=5.099 mm, ∑CT / TTL=0.498.

[0096] The axial distance SAG11 from the intersection of the object side surface of the first lens and the optical axis to the effective half-aperture vertex of the object side surface of the first lens is 0.299 mm, the center thickness CT1 of the first lens on the optical axis is 0.738 mm, and SAG11 / CT1 is 0.405.

[0097] The maximum effective semi-aperture DT42 of the image side of the fourth lens is 2.101 mm, half of the diagonal length of the effective pixel area of ​​the photosensitive element on the imaging surface of the infrared optical lens is ImgH=3.000 mm, and DT42 / ImgH=0.700.

[0098] The total effective focal length of the infrared optical lens is f=3.693 mm, the entrance pupil diameter EPD of the infrared optical lens is EPD=1.957 mm, and f / EPD=1.887.

[0099] The distance TTL from the center of the object side surface of the first lens to the imaging surface of the infrared optical lens on the optical axis is 5.099 mm, and its ratio to half the diagonal length ImgH of the effective pixel area on the imaging surface of the infrared optical lens is TTL / ImgH=1.700.

[0100] Embodiment three:

[0101] In this embodiment, the total effective focal length of the infrared optical lens is f=3.693 mm, and the first lens, the second lens, the third lens and the fourth lens are all resin lenses, the center is a lens, and the edges are corroded and matte treated. The material, refractive index and effective focal length are as follows:

[0102] The first lens is made of E48R, with a refractive index of 1.531, an effective focal length of f1 = 4.589 mm, an effective aperture of 0.979 mm on the object side, and an effective aperture of 1.026 mm on the image side;

[0103] The second lens is made of EP5000, with a refractive index of 1.635, an effective focal length of f2 = 69.587 mm, an effective aperture of 1.024 mm on the object side, and an effective aperture of 1.133 mm on the image side;

[0104] The third lens is made of E48R, with a refractive index of 1.531, an effective focal length of f3 = 5.097mm, an effective aperture of 1.151mm on the object side, and 1.519mm on the image side;

[0105] The fourth lens is made of E48R, has a refractive index of 1.531, an effective focal length of f4=-7.044mm, an effective aperture on the object side is 2.136mm, and an effective aperture on the image side is 2.600mm.

[0106] The ratio of the effective focal length f1 of the first lens to the total effective focal length f of the infrared optical lens is f1 / f=1.243;

[0107] The effective focal length f1 of the first lens, the effective focal length f2 of the second lens, the effective focal length f3 of the third lens and the total effective focal length f of the infrared optical lens satisfy |f / f1|+|f / f2|+|f / f3|=1.582.

[0108] The object side curvature radius of the first lens is R1=1.764 mm, and its ratio to the total effective focal length f of the infrared optical lens is R1 / f=0.478.

[0109] The sum of the center thicknesses of the first lens, the second lens, the third lens and the fourth lens on the optical axis ∑CT=2.593 mm, the spacing distance between the object side surface of the first lens and the imaging surface of the infrared optical lens on the optical axis TTL=5.183 mm, ∑CT / TTL=0.500.

[0110] The axial distance SAG11 from the intersection of the object side surface of the first lens and the optical axis to the effective half-aperture vertex of the object side surface of the first lens is 0.296 mm, the center thickness CT1 of the first lens on the optical axis is 0.697 mm, and SAG11 / CT1 is 0.425.

[0111] The maximum effective semi-aperture DT42 of the image side of the fourth lens is 2.136 mm, half of the diagonal length of the effective pixel area of ​​the photosensitive element on the imaging surface of the infrared optical lens is ImgH=3.000 mm, and DT42 / ImgH=0.712.

[0112] The total effective focal length of the infrared optical lens is f=3.693 mm, the entrance pupil diameter EPD of the infrared optical lens is EPD=1.957 mm, and f / EPD=1.887.

[0113] The distance from the center of the object side surface of the first lens to the imaging surface of the infrared optical lens on the optical axis is TTL=5.183 mm, and its ratio to half the diagonal length ImgH of the effective pixel area on the imaging surface of the infrared optical lens is TTL / ImgH=1.728.

[0114] It can be seen from the above technical solutions that the present invention has the following beneficial effects:

[0115] The infrared optical lens and infrared optical device of the present invention can improve the resolution of the lens, reduce optical distortion, and ensure relative illumination by optimizing parameters such as lens thickness, focal length, and effective aperture, and can be widely used in optical devices in the infrared band.

[0116] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0117] In addition, it should be understood that although the present specification is described according to embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that those skilled in the art can understand.

Claims

1. An infrared optical lens, characterized in that: The infrared optical lens is composed of a first lens, a second lens, a third lens and a fourth lens from the object side to the image side, and the object side surfaces and the image side surfaces of the first lens, the second lens, the third lens and the fourth lens are all aspherical surfaces, wherein: The first lens has positive refractive power, and its object side surface is convex at the optical axis; The second lens has positive or negative optical power, and its object side optical axis is concave, and its image side optical axis is convex; The third lens has positive refractive power, and its object side optical axis is concave, and its image side optical axis is convex; The fourth lens has negative optical power, and its object side surface is convex at the optical axis, and has at least one concave surface off the axis on the object side surface, and its image side surface is concave at the optical axis, and has at least one convex surface off the axis on the image side surface; The effective focal length f1 of the first lens and the total effective focal length f of the infrared optical lens satisfy 1.2<f1 / f<1.5, and 3.69mm≤f≤3.70mm, and the wavelength range of the light source is 812nm~832nm; The effective focal length f1 of the first lens, the effective focal length f2 of the second lens, the effective focal length f3 of the third lens and the total effective focal length f of the infrared optical lens satisfy 1.5<|f / f1|+|f / f2|+|f / f3|<2.1; The object side curvature radius R1 of the first lens and the total effective focal length f of the infrared optical lens satisfy 0.1<R1 / f<0.6; The sum of the center thicknesses ∑CT of the first lens, the second lens, the third lens and the fourth lens on the optical axis and the spacing distance TTL from the object side of the first lens to the imaging surface of the infrared optical lens on the optical axis satisfy 0.45<∑CT / TTL<0.51; An axial distance SAG11 from the intersection of the object side surface of the first lens and the optical axis to the effective half-aperture vertex of the object side surface of the first lens and a center thickness CT1 of the first lens on the optical axis satisfy 0.35<SAG11 / CT1<0.45; The maximum effective semi-aperture DT42 of the image side surface of the fourth lens and half of the diagonal length ImgH of the effective pixel area of ​​the photosensitive element on the imaging surface of the infrared optical lens satisfy 0.68<DT42 / ImgH<0.72; The distance TTL from the center of the object side surface of the first lens to the imaging surface of the infrared optical lens on the optical axis and half of the diagonal length of the effective pixel area on the imaging surface of the infrared optical lens ImgH meet 1.7 <TTL / ImgH<1.85; In the infrared optical lens: The effective aperture of the first lens on the object side is 0.97mm to 0.98mm, and the effective aperture of the image side is 0.99mm to 1.05mm; The effective aperture of the second lens on the object side is 0.95mm to 1.04mm, and the effective aperture of the image side is 1.11mm to 1.16mm; The effective aperture of the third lens on the object side is 1.14mm to 1.19mm, and the effective aperture of the image side is 1.45mm to 1.57mm; The effective aperture of the fourth lens on the object side is 2.05 mm to 2.14 mm, and the effective aperture of the fourth lens on the image side is 2.52 mm to 2.61 mm.

2. The infrared optical lens according to claim 1, characterized in that: The total effective focal length f of the infrared optical lens and the entrance pupil diameter EPD of the infrared optical lens satisfy 1.8<f / EPD<1.

9.

3. The infrared optical lens according to claim 1, characterized in that: The infrared optical lens also includes: A filter, located on the image side of the fourth lens; A lens barrel, used for encapsulating the first lens, the second lens, the third lens and the fourth lens; A plurality of spacer rings are packaged between the first lens and the second lens, and / or the second lens and the third lens, and / or the third lens and the fourth lens.

4. Infrared optical device, characterized in that The infrared optical device is provided with at least one infrared optical lens according to any one of claims 1 to 3.

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