Imaging lens

Abstract

The utility model discloses an imaging lens which comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are sequentially arranged from an object plane to an image plane along an optical axis. Wherein the first lens is a negative-focal-power lens, the second lens is a positive-focal-power lens, the third lens is a positive-focal-power lens, and the fourth lens and the fifth lens both have focal power and are opposite in focal power; the focal power of the first lens is phi 1, the focal power of the second lens is phi 2, the focal power of the third lens is phi 3, and the focal power of the imaging lens is phi; wherein-0.75 < = (phi 1 + phi 2) / phi < =-0.05, and 0.01 < = (phi 1 + phi 2 + phi 3) / phi < = 0.55. According to the technical scheme, the imaging lens comprises the five lenses, the focal power matching mode of the five lenses is set, and the design scheme of the imaging lens which is simple in structure, low in cost and small in distortion is achieved.

Description

Technical Field

[0001] The embodiment of the utility model relates to the technical field of optical devices, and in particular to an imaging lens. Background Art

[0002] As people's safety awareness continues to improve, surveillance cameras play an increasingly important role in machine vision, artificial intelligence, criminal investigation monitoring, unmanned driving, etc., all of which have promoted the development of the security monitoring field.

[0003] In recent years, many series of surveillance lenses have been launched for different purposes or environments. Among them, the 6.0mm focal length lens has a relatively large market share due to its unique performance. However, the distortion of this type of lens on the market is generally greater than 15%, which is large and affects the imaging effect. Utility Model Content

[0004] The utility model provides an imaging lens, which realizes an imaging lens with small distortion by reasonably setting a lens composition mode and a focal length distribution mode.

[0005] The embodiment of the utility model provides an imaging lens, comprising a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in sequence from the object plane to the image plane along the optical axis;

[0006] Wherein, the first lens is a negative power lens, the second lens is a positive power lens, the third lens is a positive power lens, and the fourth lens and the fifth lens both have power and opposite power;

[0007] The focal power of the first lens is Φ1, the focal power of the second lens is Φ2, the focal power of the third lens is Φ3, and the focal power of the imaging lens is Φ;

[0008] Among them, -0.75≤(Φ1+Φ2) / Φ≤-0.05, 0.01≤(Φ1+Φ2+Φ3) / Φ≤0.55.

[0009] Optionally, the focal power of the fourth lens is Φ4, and the focal power of the fifth lens is Φ5;

[0010] Among them, -0.65≤Φ1 / Φ≤-0.25, 0.15≤Φ2 / Φ≤0.45, 0.55≤Φ3 / Φ≤0.68,

[0011] -1.50≤Φ4 / Φ≤1.50, -1.25≤Φ5 / Φ≤1.25.

[0012] Optionally, the refractive index of the third lens is Nd3, and the Abbe constant of the third lens is Vd3;

[0013] Among them, 1.40≤Nd3≤1.65, 75.5≤Vd3≤96.50.

[0014] Optionally, an axial distance between the centers of the first lens and the second lens is TH12, an axial distance between the centers of the second lens and the third lens is TH23, and an axial distance between the centers of the third lens and the fourth lens is TH34;

[0015] Among them, 1.55≤TH12≤5.50mm; 0.05≤TH23≤1.85mm; 0.05≤TH34≤1.25mm.

[0016] Optionally, the center thickness of the first lens is CT1, and the center thickness of the second lens is CT2;

[0017] Among them, 0.65≤CT1≤2.45, 1.45≤CT2≤2.85.

[0018] Optionally, the total image height of the imaging lens is IC, the total optical length of the imaging lens is TTL, the total focal length of the imaging lens is f, and the optical back focus of the imaging lens is OBFL;

[0019] Among them, 0.13≤IC / TTL≤0.18; 3.45≤TTL / f≤4.25; 0.18≤OBFL / TTL≤0.45.

[0020] Optionally, the first lens includes a first object-side surface close to the object plane and a first image-side surface close to the image plane, the first object-side surface is a concave surface, and the first image-side surface is a concave surface;

[0021] The second lens comprises a second image-side surface close to the image plane, and the second image-side surface is a convex surface;

[0022] The third lens comprises a third object-side surface close to the object plane and a third image-side surface close to the image plane, the third object-side surface is a convex surface or a plane, and the third image-side surface is a convex surface;

[0023] The fourth lens includes a fourth image-side surface close to the image plane, and the fifth lens includes a fifth object-side surface close to the object plane and a fifth image-side surface close to the image plane; the fourth image-side surface is a concave surface, the fifth object-side surface is a convex surface, and the fifth image-side surface is a convex surface; or, the fourth image-side surface is a convex surface, the fifth object-side surface is a concave surface, and the fifth image-side surface is a convex surface.

[0024] Optionally, the first lens, the second lens, the fourth lens and the fifth lens are all plastic aspheric lenses;

[0025] The third lens is a glass spherical lens.

[0026] Optionally, the imaging lens further includes an aperture stop and a filter;

[0027] The aperture stop is disposed in the optical path between the second lens and the third lens; or, the aperture stop is disposed in the optical path between the third lens and the fourth lens;

[0028] The filter is arranged in the optical path between the fifth lens and the image plane.

[0029] Optionally, the aperture number of the imaging lens is F#;

[0030] Among them, 1.52≤F#≤1.65.

[0031] The imaging lens provided by the embodiment of the utility model is configured to include five lenses, so that the number of lenses in the entire optical system is small, which is conducive to realizing a miniaturized imaging lens configuration. In addition, in the imaging lens provided by the embodiment of the utility model, by configuring the focal power matching mode and specific focal power values ​​of the five lenses, the characteristics of small distortion and large aperture of the imaging lens can be realized, which is conducive to improving the imaging quality.

[0032] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present utility model, nor are they intended to limit the scope of the present utility model. Other features of the present utility model will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0034] Figure 1 This is a schematic structural diagram of an imaging lens provided in Embodiment 1 of the present utility model;

[0035] Figure 2 It is a schematic diagram of a spherical aberration curve of an imaging lens provided in the first embodiment of the utility model;

[0036] Figure 3 This is a schematic diagram of a light fan of an imaging lens provided in the first embodiment of the utility model;

[0037] Figure 4 This is a schematic diagram of field curvature distortion of an imaging lens provided in Embodiment 1 of the present utility model;

[0038] Figure 5 This is a schematic diagram of the structure of an imaging lens provided in Embodiment 2 of the present utility model;

[0039] Figure 6 This is a schematic diagram of a spherical aberration curve of an imaging lens provided in Embodiment 2 of the present utility model;

[0040] Figure 7 This is a schematic diagram of a light fan of an imaging lens provided in Embodiment 2 of the present utility model;

[0041] Figure 8 This is a schematic diagram of field curvature distortion of an imaging lens provided in Embodiment 2 of the present utility model;

[0042] Fig. 9 This is a schematic diagram of the structure of an imaging lens provided by Embodiment 3 of the present utility model;

[0043] Fig.10 This is a schematic diagram of a spherical aberration curve of an imaging lens provided in Embodiment 3 of the present utility model;

[0044] Fig.11 This is a schematic diagram of a light fan of an imaging lens provided in Embodiment 3 of the present utility model;

[0045] Fig.12 This is a schematic diagram of field curvature distortion of an imaging lens provided in Embodiment 3 of the present utility model;

[0046] Fig.13 This is a schematic diagram of the structure of an imaging lens provided by Embodiment 4 of the present utility model;

[0047] Fig.14 This is a schematic diagram of a spherical aberration curve of an imaging lens provided by the fourth embodiment of the utility model;

[0048] Fig.15 This is a schematic diagram of a light fan of an imaging lens provided by a fourth embodiment of the utility model;

[0049] Fig.16 This is a schematic diagram of field curvature distortion of an imaging lens provided in Embodiment 4 of the present utility model. DETAILED DESCRIPTION

[0050] In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0051] Embodiment 1

[0052] Figure 1 is a schematic diagram of the structure of an imaging lens provided in the first embodiment of the utility model, such as Figure 1 As shown, the imaging lens provided by the first embodiment of the utility model comprises a first lens 110, a second lens 120, a third lens 130, a fourth lens 140 and a fifth lens 150 arranged in sequence from the object plane to the image plane along the optical axis; wherein the first lens 110 is a negative optical power lens, the second lens 120 is a positive optical power lens, the third lens 130 is a positive optical power lens, the fourth lens 140 and the fifth lens 150 both have optical power and the optical power is opposite; the optical power of the first lens 110 is Φ1, the optical power of the second lens 120 is Φ2, the optical power of the third lens 130 is Φ3, and the optical power of the imaging lens is Φ; wherein, -0.75≤

[0053] (Φ1+Φ2) / Φ≤-0.05, 0.01≤(Φ1+Φ2+Φ3) / Φ≤0.55.

[0054] Specifically, the focal length is equal to the difference between the convergence of the image-side light beam and the convergence of the object-side light beam, and it characterizes the ability of the optical system to deflect light. The larger the absolute value of the focal length, the stronger the ability to bend light, and the smaller the absolute value of the focal length, the weaker the ability to bend light. When the focal length is a positive number, the refraction of light is convergent; when the focal length is a negative number, the refraction of light is divergent. The focal length can be used to characterize a certain refractive surface of a lens (i.e., a surface of a lens), can be used to characterize a certain lens, and can also be used to characterize a system formed by multiple lenses (i.e., a lens group). In the embodiment of the utility model, setting the first lens 110 as a negative focal length lens can ensure that the first lens 110 can effectively deflect large-angle incident light, thereby effectively increasing the field of view of the imaging lens, and ensuring that the optical system can have wide-angle or even ultra-wide-angle characteristics. And setting the first lens 110 as a negative focal length lens can quickly expand the light aperture and increase the aperture of the lens. The second lens 120 and the third lens 130 are set as positive power lenses, so that the second lens 120 and the third lens 130 can realize timely correction of the large aberrations generated by the first lens 110, especially can have a significant correction effect on the edge aberrations of the optical system, thereby improving the imaging resolution of the optical system. Further setting the fourth lens 140 and the fifth lens 150 both have optical power and the optical power is opposite, which can ensure the aberration balance of the lens and the stability of high and low temperature performance while eliminating the high-order aberrations of the lens as much as possible, and at the same time can control the target surface (size) and improve the image quality of the lens, meeting the use requirements in more situations.

[0055] Specifically, the focal power Φ1 of the first lens 110, the focal power Φ2 of the second lens 120 and the focal power Φ of the imaging lens satisfy -0.75≤(Φ1+Φ2) / Φ≤-0.05. When the above conditions are met, the optical system can have the characteristic of small optical distortion. Further, the focal power Φ1 of the first lens 110, the focal power Φ2 of the second lens 120, the focal power Φ3 of the third lens 130 and the focal power Φ of the imaging lens satisfy 0.01≤(Φ1+Φ2+Φ3) / Φ≤0.55. When the above conditions are met, the system can have the characteristic of large aperture.

[0056] Furthermore, the aperture number of the imaging lens is F#, wherein 1.52≤F#≤1.65. The aperture number is within this range, ensuring that the imaging lens has a large aperture to meet the imaging requirements.

[0057] In summary, the imaging lens provided by the embodiment of the utility model is provided with five lenses, so that the number of lenses in the entire optical system is small, which is conducive to realizing a miniaturized imaging lens setting. In addition, in the imaging lens provided by the embodiment of the utility model, by setting the focal power matching mode and specific focal power values ​​of the five lenses, the characteristics of small distortion and large aperture of the imaging lens can be realized, which is conducive to improving the imaging quality.

[0058] Based on the above embodiment, the optical power of the fourth lens 140 is Φ4, and the optical power of the fifth lens 150 is Φ5; wherein, -0.65≤Φ1 / Φ≤-0.25, 0.15≤Φ2 / Φ≤0.45, 0.55≤Φ3 / Φ≤0.68, -1.50≤Φ4 / Φ≤1.50, and -1.25≤Φ5 / Φ≤1.25.

[0059] Specifically, the focal length of the first lens 110 within this range can smoothly collect the object light into the imaging system, reducing the proportion of high-order aberrations. At the same time, by reasonably controlling the value of Φ1 / Φ, the head aperture of the system can be reduced, and the aperture of the lens system can be miniaturized.

[0060] The focal length of the second lens 120 within this range can diverge the light at a gentler deflection angle, thereby increasing the entrance pupil diameter, which is beneficial to achieving a large aperture characteristic of the optical system.

[0061] The focal length of the third lens 130 within this range can make the light of each field of view emerge at a reasonable angle, which can effectively reduce the aberration related to the field of view and also effectively reduce the tolerance sensitivity of the lens.

[0062] The fourth lens 140 and the fifth lens 150 are matched with positive and negative optical powers. When the fourth lens 140 is a negative optical power lens, the fifth lens 150 is a positive optical power lens; when the fourth lens 140 is a positive optical power lens, the fifth lens 150 is a negative optical power lens. The fourth lens 140 and the fifth lens 150 are matched with positive and negative optical powers and the optical power range is appropriately set, which can make the light deflection angle transition smooth, and can also make the system have a smaller tolerance sensitivity while ensuring the imaging quality.

[0063] Based on the above embodiment, the refractive index of the third lens 130 is Nd3, and the Abbe constant of the third lens 130 is Vd3; wherein 1.40≤Nd3≤1.65, 75.5≤Vd3≤96.50. When the refractive index Nd3 of the third lens 130 and the Abbe constant Vd3 meet the above conditions, the chromatic aberration of the optical system can be effectively corrected, which is beneficial to the improvement of the resolution of the optical system.

[0064] Based on the above embodiment, the center axial distance between the first lens 110 and the second lens 120 is TH12, the center axial distance between the second lens 120 and the third lens 130 is TH23, and the center axial distance between the third lens 130 and the fourth lens 140 is TH34; wherein, 1.55≤TH12≤5.50mm; 0.05≤TH23≤1.85mm; 0.05≤TH34≤1.25mm. When the above conditions are met, the total optical length TTL of the imaging lens can be guaranteed to meet TTL≤22.5mm, and the imaging lens structure is compact.

[0065] Based on the above embodiment, the center thickness of the first lens 110 is CT1, and the center thickness of the second lens 120 is CT2; wherein 0.65≤CT1≤2.45, 1.45≤CT2≤2.85. When the above conditions are met, the optical system can be ensured to have good adaptability to high and low temperature environments.

[0066] Based on the above embodiment, the total image height of the imaging lens is IC, the total optical length of the imaging lens is TTL, the total focal length of the imaging lens is f, and the optical back focus of the imaging lens is OBFL; wherein, 0.13≤IC / TTL≤0.18; 3.45≤TTL / f≤4.25; 0.18≤OBFL / TTL≤0.45. When the above conditions are met, it can be ensured that the system has the characteristics of a large target surface, a short total length, and a long optical back focus.

[0067] On the basis of the above embodiments, the first lens 110 includes a first object-side surface close to the object plane and a first image-side surface close to the image plane, the first object-side surface is convex, and the first image-side surface is concave; the second lens 12 includes a second image-side surface close to the image plane, and the second image-side surface is convex; the third lens 130 includes a third object-side surface close to the object plane and a third image-side surface close to the image plane, the third object-side surface is a convex surface or a plane, and the third image-side surface is a convex surface; the fourth lens 140 includes a fourth image-side surface close to the image plane, and the fifth lens 150 includes a fifth object-side surface close to the object plane and a fifth image-side surface close to the image plane; the fourth image-side surface is concave, the fifth object-side surface is convex, and the fifth image-side surface is convex; or, the fourth image-side surface is convex, the fifth object-side surface is concave, and the fifth image-side surface is convex.

[0068] Specifically, the object side of the lens can be understood as the surface of the lens close to the object plane, and the image side of the lens can be understood as the surface of the lens close to the image plane. Specifically, the object side of the first lens 110 is a convex surface, and the image side is a concave surface, which can be understood as the object side of the first lens 110 is convex toward the object plane at the near optical axis position, and the image side is concave toward the image plane at the near optical axis position, that is, the first lens 110 is a lens with a convex-concave structure. The image side of the second lens 120 is a convex surface, which can be understood as the image side of the second lens 120 is convex toward the image plane at the near optical axis position. The object side of the third lens 130 is a convex surface or a plane, and the image side is a convex surface, which can be understood as the object side of the third lens 130 is convex toward the object plane or remains flat at the near optical axis position, and the image side is convex toward the image plane at the near optical axis position, that is, the third lens 130 is a lens with a double convex structure or a plane-convex structure. The image side surface of the fourth lens 140 is a concave surface, which can be understood as the image side surface of the fourth lens 140 is concave toward the image plane at the near optical axis position; the object side surface of the fifth lens 150 is a convex surface, and the image side surface is a convex surface, which can be understood as the object side surface of the fifth lens 150 is convex toward the object plane at the near optical axis position, and the image side surface is convex toward the image plane at the near optical axis position, that is, the fifth lens 150 is a lens with a double convex structure. Alternatively, the image side surface of the fourth lens 140 is a convex surface, which can be understood as the image side surface of the fourth lens 140 is convex toward the image plane at the near optical axis position; the object side surface of the fifth lens 150 is a concave surface, and the image side surface is a convex surface, which can be understood as the object side surface of the fifth lens 150 is concave toward the object plane at the near optical axis position, and the image side surface is convex toward the image plane at the near optical axis position, that is, the fifth lens 150 is a lens with a concave-convex structure. By reasonably setting the surface shape of each lens, it can be ensured that the edge light trend is smoother, the relative illumination between the edge image and the center image is improved, and the imaging effect is improved.

[0069] On the basis of the above embodiment, the first lens 110 , the second lens 120 , the fourth lens 140 and the fifth lens 150 are all plastic aspherical lenses; and the third lens 130 is a glass spherical lens.

[0070] Specifically, the characteristic of the aspheric lens is that the curvature changes continuously from the center of the lens to the periphery of the lens. Unlike the spherical lens with a constant curvature from the center of the lens to the periphery of the lens, the aspheric lens has a better curvature radius characteristic, and has the advantages of improving distortion aberration and improving astigmatism aberration. Setting the first lens 110, the second lens 120, the fourth lens 140 and the fifth lens 150 to use aspheric lenses can eliminate the aberrations that occur during imaging as much as possible, thereby improving the imaging quality of the lens. On this basis, the aspheric lens can be a plastic aspheric lens, which is conducive to reducing the processing technology of the aspheric lens, and the cost of the aspheric lens is relatively low.

[0071] Furthermore, the spherical lens is characterized by having a constant curvature from the center of the lens to the periphery of the lens, ensuring that the lens is set in a simple manner. Furthermore, since the thermal expansion coefficient of a glass lens is small and the stability is good, the third lens 130 can be set as a glass spherical lens. The thermal properties of a glass spherical lens are more stable, and when it bears more optical power, it can ensure that the lens has good resolution in a wider temperature range (-40°C to 80°C). In addition, compared with plastic aspherical lenses, the range of glass materials available is wider, and the refractive index and Abbe constant are relatively free to choose. To a certain extent, the high-level aberrations and chromatic aberrations of the lens can be controlled to meet the use requirements under complex conditions.

[0072] In the imaging lens provided by the embodiment of the utility model, a glass spherical lens and a plastic aspherical lens can be mixed and matched, so that the cost of the imaging lens can be effectively controlled while ensuring the optical performance of the imaging lens; at the same time, the materials of each lens have a mutual compensation effect, which can ensure that it can still be used normally in high and low temperature environments.

[0073] Based on the above embodiments, continue to refer to Figure 1 As shown, the imaging lens further includes an aperture stop 160 and a filter 170; the aperture stop 160 is disposed in the optical path between the second lens 120 and the third lens 130; or, the aperture stop 160 is disposed in the optical path between the third lens 130 and the fourth lens 140; the filter 170 is disposed in the optical path between the fifth lens 150 and the image plane.

[0074] Specifically, the aperture stop 160 can be provided to adjust the propagation direction of the light beam, which is beneficial to improving the imaging quality. In addition, the aperture stop 160 in the imaging lens is located in the optical path between the second lens 120 and the third lens 130, or is provided in the optical path between the third lens 130 and the fourth lens 140. The aperture stop 160 is located in the middle of the imaging lens to ensure that the front and rear apertures of the imaging lens are minimized.

[0075] As a feasible implementation, specific parameters in the imaging lens are described below.

[0076] Table 1 Optical design values ​​of the imaging lens in Example 1

[0077] Conditional expression Example 1 Lower limit Upper limit Nd3 1.46 1.40 1.65 Vd3 90.27 75.50 96.50 (Φ1+Φ2) / Φ -0.29 -0.75 -0.05 (Φ1+Φ2+Φ3) / Φ 0.34 0.01 0.55 F# 1.60 1.52 1.65 Φ1 / Φ -0.51 -0.65 -0.25 Φ2 / Φ 0.22 0.15 0.45 Φ3 / Φ 0.63 0.55 0.68 Φ4 / Φ -1.02 -1.50 1.50 Φ5 / Φ 1.03 -1.25 1.25 TH12 4.00 1.55 5.50 TH23 0.50 0.05 1.85 TH34 0.21 0.05 1.25 CT1 0.96 0.65 2.45 CT2 1.73 1.45 2.85 IC / TTL 0.15 0.13 0.18 TTL / f 3.93 3.45 4.25 OBFL / TTL 0.30 0.18 0.45

[0078] Table 2 Design values ​​of optical physical parameters of an imaging lens

[0079]

[0080] The surface numbers in Table 2 are numbered according to the order of the surfaces of each lens. "S1" represents the object surface of the first lens, "S2" represents the image surface of the first lens, and so on. "PL" represents a plane; "STO" represents the aperture of the lens; the radius of curvature represents the curvature of the lens surface, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side; "infinite" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface, the refractive index represents the ability of the material between the current surface and the next surface to deflect light, and the space represents that the current position is air with a refractive index of 1; the Abbe constant represents the dispersion characteristics of the material between the current surface and the next surface to the light; the k value represents the numerical value of the cone coefficient of the aspheric surface; the aperture represents the aperture size of the current surface.

[0081] The aspheric cone coefficient can be defined by the following aspheric formula, but is not limited to the following representation method:

[0082]

[0083] Among them, z is the axial vector height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitted sphere, which is the inverse of the radius of curvature; k is the fitting cone coefficient; AG is the coefficient of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order terms of the aspheric polynomial.

[0084] Table 3 Aspheric coefficients of an imaging lens

[0085]

[0086] Among them, "-2.5864E-03" means -2.5864*10 -3 The remaining coefficients are expressed in this way.

[0087] Based on the above parameter definitions, the optical parameters that can be achieved by the imaging lens in the first embodiment of the present invention are as follows: focal length f is 5.72 mm, F# is 1.60, field of view angle DFOV=64°, and total optical length TTL=22.48 mm.

[0088] Furthermore, Figure 2 This is a schematic diagram of the spherical aberration curve of an imaging lens provided by the first embodiment of the utility model. The vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the pupil radius is 1.7338mm; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm). The different linear curves in the figure represent different wavelengths of system imaging (436nm, 486nm, 546nm, 588nm and 656nm respectively), as shown in FIG. Figure 2It can be seen that the axial aberrations at different wavelengths are all controlled within the range of (-0.1mm, +0.1mm), indicating that the spherical aberration of the imaging lens at each wavelength is well controlled.

[0089] Figure 3 This is a schematic diagram of the light fan of an imaging lens provided in Example 1 of the utility model. The light fan diagram is one of the most commonly used evaluation methods in modern optical design. The horizontal axis is the beam aperture, and the vertical axis is the vertical axis aberration. The most ideal curve is a straight line that coincides with the horizontal axis, indicating that all light rays converge at the same point on the image plane, and the corresponding interval on the vertical axis of the curve is the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberrations of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. By Figure 3 It can be seen that each wavelength (436nm, 486nm, 546nm, 588nm and 656nm) in each field of view is close to the horizontal axis, indicating that the vertical axis aberration of each wavelength of the system is well corrected. At the same time, there is no obvious dispersion of each wavelength, indicating that the chromatic aberration of the system is also well corrected, thereby ensuring that the optical system can achieve high-resolution imaging requirements.

[0090] Figure 4 Schematic diagram of field curvature distortion of an imaging lens provided in the first embodiment of the present utility model. In the coordinate system on the left side of the figure, the horizontal coordinate represents the magnitude of the field curvature, and the unit is mm; the vertical coordinate represents the normalized image height, and there is no unit; Figure 4 As can be seen from the left figure, the field curvature of the lens provided by this embodiment is effectively controlled at each wavelength (436nm, 486nm, 546nm, 588nm and 656nm), that is, when imaging, the difference between the image quality at the center and the image quality at the periphery is small. In the coordinate system on the right, the horizontal coordinate represents the size of the distortion, in %, and the vertical coordinate represents the normalized image height, without unit; Figure 4 It can be seen from the figure on the right that the maximum distortion of the lens provided in this embodiment is controlled within 10%, the distortion is well corrected, the imaging distortion is small, and the difference between the image and the actual object is small.

[0091] In summary, the imaging lens provided in the first embodiment of the present invention adopts a mixed combination of 1 spherical glass lens and 4 aspherical plastic transparent lenses. By matching the lens materials and reasonably allocating the optical focal length of each component, it can match the 1 / 2.7″ target surface sensor, and the resolution can reach 4K image quality requirements, realizing 24-hour all-weather high-definition monitoring, and the real-life picture is clear in high and low temperature environments; the optical distortion of the lens system is smaller than that of the lenses with the same specifications and parameters on the market. At the same time, in terms of manufacturability, each lens has low sensitivity, and the lens surface is simple and easy to manufacture, which reduces the processing cost of the system; the lens system has high cost performance.

[0092] Embodiment 2

[0093] Figure 5 : is a schematic diagram of the structure of an imaging lens provided in the second embodiment of the present utility model. Figure 5 As shown, the imaging lens provided by the second embodiment of the present invention includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140 and a fifth lens 150 which are arranged in sequence from the object plane to the image plane along the optical axis; wherein the first lens 110 is a negative optical power lens, the second lens 120 is a positive optical power lens, the third lens 130 is a positive optical power lens, the fourth lens 140 and the fifth lens 150 both have optical power and the optical power is opposite; the optical power of the first lens 110 is Φ1, the optical power of the second lens 120 is Φ2, the optical power of the third lens 130 is Φ3, and the optical power of the imaging lens is Φ; wherein, -0.75≤(Φ1+Φ2) / Φ≤-0.05, 0.01≤(Φ1+Φ2+Φ3) / Φ≤0.55.

[0094] The configuration of the above-mentioned lens is the same as that in the first embodiment, and will not be described in detail here.

[0095] As another feasible implementation, specific parameters in the imaging lens are described below.

[0096] Table 4 Optical design values ​​of the imaging lens in Example 2

[0097] Conditional expression Example 2 Lower limit Upper limit Nd3 1.50 1.40 1.65 Vd3 81.61 75.50 96.50 (Φ1+Φ2) / Φ -0.19 -0.75 -0.05 (Φ1+Φ2+Φ3) / Φ 0.43 0.01 0.55 F# 1.62 1.52 1.65 Φ1 / Φ -0.48 -0.65 -0.25 Φ2 / Φ 0.29 0.15 0.45 Φ3 / Φ 0.62 0.55 0.68 Φ4 / Φ -1.14 -1.50 1.50 Φ5 / Φ 1.07 -1.25 1.25 TH12 4.35 1.55 5.50 TH23 0.15 0.05 1.85 TH34 0.21 0.05 1.25 CT1 1.55 0.65 2.45 CT2 1.88 1.45 2.85 IC / TTL 0.17 0.13 0.18 TTL / f 4.12 3.45 4.25 OBFL / TTL 0.27 0.18 0.45

[0098] Table 5 Design values ​​of optical physical parameters of an imaging lens

[0099]

[0100] The surface numbers in Table 5 are numbered according to the order of the surfaces of each lens. "S1" represents the object surface of the first lens, "S2" represents the image surface of the first lens, and so on. "PL" represents a plane; "STO" represents the aperture of the lens; the radius of curvature represents the curvature of the lens surface, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side; "infinite" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface, the refractive index represents the ability of the material between the current surface and the next surface to deflect light, and the space represents that the current position is air with a refractive index of 1; the Abbe constant represents the dispersion characteristics of the material between the current surface and the next surface to light; the k value represents the numerical value of the cone coefficient of the aspheric surface; the aperture represents the aperture size of the current surface.

[0101] The aspheric cone coefficient can be defined by the following aspheric formula, but is not limited to the following representation method:

[0102]

[0103] Among them, z is the axial vector height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitted sphere, which is the inverse of the radius of curvature; k is the fitting cone coefficient; AG is the coefficient of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order terms of the aspheric polynomial.

[0104] Table 6 Aspheric coefficients of an imaging lens

[0105]

[0106] Among them, "-5.4580E-04" means -5.4580*10 -4 The remaining coefficients are expressed in this way.

[0107] Based on the above parameter definitions, the optical parameters that can be achieved by the imaging lens in the second embodiment of the present invention are as follows: focal length f is 5.43 mm, F# is 1.62, field of view angle DFOV=66.5°, and total optical length TTL=22.39 mm.

[0108] Furthermore, Figure 6 This is a schematic diagram of the spherical aberration curve of an imaging lens provided by the second embodiment of the utility model. The vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the pupil radius is 1.6070mm; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm). The different linear curves in the figure represent different wavelengths of system imaging (436nm, 486nm, 546nm, 588nm and 656nm respectively), as shown in FIG. Figure 6 It can be seen that the axial aberrations at different wavelengths are all controlled within the range of (-0.1mm, +0.1mm), indicating that the spherical aberration of the imaging lens at each wavelength is well controlled.

[0109] Figure 7 This is a schematic diagram of the light fan of an imaging lens provided in Example 2 of the utility model. The light fan diagram is one of the most commonly used evaluation methods in modern optical design. The horizontal axis is the beam aperture, and the vertical axis is the vertical axis aberration. The most ideal curve is a straight line that coincides with the horizontal axis, indicating that all light rays converge at the same point on the image plane, and the corresponding interval on the vertical axis of the curve is the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberrations of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. By Figure 7It can be seen that each wavelength (436nm, 486nm, 546nm, 588nm and 656nm) in each field of view is close to the horizontal axis, indicating that the vertical axis aberration of each wavelength of the system is well corrected. At the same time, there is no obvious dispersion of each wavelength, indicating that the chromatic aberration of the system is also well corrected, thereby ensuring that the optical system can achieve high-resolution imaging requirements.

[0110] Figure 8 Schematic diagram of field curvature distortion of an imaging lens provided by Embodiment 2 of the present utility model. In the coordinate system on the left side of the figure, the horizontal coordinate represents the magnitude of the field curvature, in units of mm; the vertical coordinate represents the normalized image height, in units of mm; Figure 8 As can be seen from the left figure, the field curvature of the lens provided by this embodiment is effectively controlled at each wavelength (436nm, 486nm, 546nm, 588nm and 656nm), that is, when imaging, the difference between the image quality at the center and the image quality at the periphery is small. In the coordinate system on the right, the horizontal coordinate represents the size of the distortion, in %, and the vertical coordinate represents the normalized image height, without unit; Figure 8 It can be seen from the figure on the right that the maximum distortion of the lens provided in this embodiment is controlled within 10%, the distortion is well corrected, the imaging distortion is small, and the difference between the image and the actual object is small.

[0111] In summary, the imaging lens provided in the second embodiment of the present invention adopts a mixed combination of 1 spherical glass lens and 4 aspherical plastic transparent lenses. By matching the lens materials and reasonably allocating the optical focal length of each component, it can match the 1 / 2.7″ target surface sensor, and the resolution can reach 4K image quality requirements, realizing 24-hour all-weather high-definition monitoring, and the real-life picture is clear in high and low temperature environments; the optical distortion of the lens system is smaller than that of the lenses with the same specifications and parameters on the market. At the same time, in terms of manufacturability, each lens has low sensitivity, and the lens surface is simple and easy to manufacture, which reduces the processing cost of the system; the lens system has high cost performance.

[0112] Embodiment 3

[0113] Fig. 9 : is a schematic diagram of the structure of an imaging lens provided in Embodiment 3 of the present utility model, such as Fig. 9As shown, the imaging lens provided by the third embodiment of the present invention includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140 and a fifth lens 150 which are arranged in sequence from the object plane to the image plane along the optical axis; wherein the first lens 110 is a negative optical power lens, the second lens 120 is a positive optical power lens, the third lens 130 is a positive optical power lens, the fourth lens 140 and the fifth lens 150 both have optical power and the optical power is opposite; the optical power of the first lens 110 is Φ1, the optical power of the second lens 120 is Φ2, the optical power of the third lens 130 is Φ3, and the optical power of the imaging lens is Φ; wherein, -0.75≤(Φ1+Φ2) / Φ≤-0.05, 0.01≤(Φ1+Φ2+Φ3) / Φ≤0.55.

[0114] Among them, in the above lens setting method, the aperture is set in the light path between the third lens and the fourth lens, and the remaining settings are the same as those in the first embodiment, which will not be repeated here.

[0115] As another feasible implementation, specific parameters in the imaging lens are described below.

[0116] Table 7 Optical design values ​​of the imaging lens in Example 3

[0117] Conditional expression Example 3 Lower limit Upper limit Nd3 1.46 1.40 1.65 Vd3 90.27 75.50 96.50 (Φ1+Φ2) / Φ -0.15 -0.75 -0.05 (Φ1+Φ2+Φ3) / Φ 0.44 0.01 0.55 F# 1.56 1.52 1.65 Φ1 / Φ -0.50 -0.65 -0.25 Φ2 / Φ 0.36 0.15 0.45 Φ3 / Φ 0.59 0.55 0.68 Φ4 / Φ -1.21 -1.50 1.50 Φ5 / Φ 1.07 -1.25 1.25 TH12 4.51 1.55 5.50 TH23 0.15 0.05 1.85 TH34 0.14 0.05 1.25 CT1 1.53 0.65 2.45 CT2 2.43 1.45 2.85 IC / TTL 0.14 0.13 0.18 TTL / f 4.10 3.45 4.25 OBFL / TTL 0.30 0.18 0.45

[0118] Table 8 Design values ​​of optical physical parameters of an imaging lens

[0119]

[0120] The surface numbers in Table 8 are numbered according to the order of the surfaces of each lens. "S1" represents the object surface of the first lens, "S2" represents the image surface of the first lens, and so on. "PL" represents a plane; "STO" represents the aperture of the lens; the radius of curvature represents the curvature of the lens surface, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side; "infinity" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface, the refractive index represents the ability of the material between the current surface and the next surface to deflect light, and the space represents that the current position is air with a refractive index of 1; the Abbe constant represents the dispersion characteristics of the material between the current surface and the next surface to the light; the k value represents the numerical value of the cone coefficient of the aspheric surface; the aperture represents the aperture size of the current surface.

[0121] The aspheric cone coefficient can be defined by the following aspheric formula, but is not limited to the following representation method:

[0122]

[0123] Among them, z is the axial vector height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitted sphere, which is the inverse of the radius of curvature; k is the fitting cone coefficient; AG is the coefficient of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order terms of the aspheric polynomial.

[0124] Table 9 Aspheric coefficients of an imaging lens

[0125]

[0126] Among them, "-6.7297E-05" means -6.7297*10 -5 The remaining coefficients are expressed in this way.

[0127] Based on the above parameter definitions, the optical parameters that can be achieved by the imaging lens in the third embodiment of the present invention are as follows: focal length f is 5.46 mm, F# is 1.56, field of view angle DFOV=66.0°, and total optical length TTL=22.38 mm.

[0128] Furthermore, Fig.10 This is a schematic diagram of the spherical aberration curve of an imaging lens provided by the third embodiment of the utility model. The vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the pupil radius is 1.6554mm; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm). The different linear curves in the figure represent different wavelengths of system imaging (436nm, 486nm, 546nm, 588nm and 656nm respectively), as shown in FIG. Fig.10 It can be seen that the axial aberrations at different wavelengths are all controlled within the range of (-0.1mm, +0.1mm), indicating that the spherical aberration of the imaging lens at each wavelength is well controlled.

[0129] Fig.11 This is a schematic diagram of the light fan of an imaging lens provided in Example 3 of the utility model. The light fan diagram is one of the most commonly used evaluation methods in modern optical design. The horizontal axis is the beam aperture, and the vertical axis is the vertical axis aberration. The most ideal curve is a straight line that coincides with the horizontal axis, indicating that all light rays converge at the same point on the image plane, and the corresponding interval on the vertical axis of the curve is the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberrations of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. By Fig.11 It can be seen that each wavelength (436nm, 486nm, 546nm, 588nm and 656nm) in each field of view is close to the horizontal axis, indicating that the vertical axis aberration of each wavelength of the system is well corrected. At the same time, there is no obvious dispersion of each wavelength, indicating that the chromatic aberration of the system is also well corrected, thereby ensuring that the optical system can achieve high-resolution imaging requirements.

[0130] Fig.12 Schematic diagram of field curvature distortion of an imaging lens provided in Embodiment 3 of the present utility model. In the coordinate system on the left side of the figure, the horizontal coordinate represents the magnitude of the field curvature, in units of mm; the vertical coordinate represents the normalized image height, in units of mm; Fig.12 As can be seen from the left figure, the field curvature of the lens provided by this embodiment is effectively controlled at each wavelength (436nm, 486nm, 546nm, 588nm and 656nm), that is, when imaging, the difference between the image quality at the center and the image quality at the periphery is small. In the coordinate system on the right, the horizontal coordinate represents the size of the distortion, in %, and the vertical coordinate represents the normalized image height, without unit; Fig.12 It can be seen from the figure on the right that the maximum distortion of the lens provided in this embodiment is controlled within 10%, the distortion is well corrected, the imaging distortion is small, and the difference between the image and the actual object is small.

[0131] In summary, the imaging lens provided in the third embodiment of the present invention adopts a mixed combination of 1 spherical glass lens and 4 aspherical plastic transparent lenses. By matching the lens materials and reasonably allocating the optical focal length of each component, it can match the 1 / 2.7″ target surface sensor, and the resolution can reach 4K image quality requirements, realizing 24-hour all-weather high-definition monitoring, and the real-life picture is clear in high and low temperature environments; the optical distortion of the lens system is smaller than that of the lenses with the same specifications and parameters on the market. At the same time, in terms of manufacturability, each lens has low sensitivity, and the lens surface is simple and easy to manufacture, which reduces the processing cost of the system; the lens system has high cost performance.

[0132] Embodiment 4

[0133] Fig.13 : is a schematic diagram of the structure of an imaging lens provided by the fourth embodiment of the utility model, such as Fig.13 As shown, the imaging lens provided by the fourth embodiment of the present invention includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140 and a fifth lens 150 arranged in sequence from the object plane to the image plane along the optical axis; wherein the first lens 110 is a negative optical power lens, the second lens 120 is a positive optical power lens, the third lens 130 is a positive optical power lens, the fourth lens 140 and the fifth lens 150 both have optical power and the optical power is opposite; the optical power of the first lens 110 is Φ1, the optical power of the second lens 120 is Φ2, the optical power of the third lens 130 is Φ3, and the optical power of the imaging lens is Φ; wherein,

[0134] -0.75≤(Φ1+Φ2) / Φ≤-0.05, 0.01≤(Φ1+Φ2+Φ3) / Φ≤0.55.

[0135] Among them, the optical focal power combination mode and the surface configuration mode of the fourth lens and the fifth lens in the above lens configuration mode are different from those in the above embodiment, and the remaining configuration modes are the same as those in the first embodiment, which will not be described again.

[0136] As another feasible implementation, specific parameters in the imaging lens are described below.

[0137] Table 10: Optical design values ​​of the imaging lens in Example 4

[0138] Conditional expression Example 4 Lower limit Upper limit Nd3 1.44 1.40 1.65 Vd3 94.50 75.50 96.50 (Φ1+Φ2) / Φ -0.52 -0.75 -0.05 (Φ1+Φ2+Φ3) / Φ 0.09 0.01 0.55 F# 1.60 1.52 1.65 Φ1 / Φ -0.36 -0.65 -0.25 Φ2 / Φ 0.23 0.15 0.45 Φ3 / Φ 0.61 0.55 0.68 Φ4 / Φ 1.24 -1.50 1.50 Φ5 / Φ -0.81 -1.25 1.25 TH12 2.46 1.55 5.50 TH23 1.52 0.05 1.85 TH34 0.78 0.05 1.25 CT1 2.15 0.65 2.45 CT2 1.89 1.45 2.85 IC / TTL 0.15 0.13 0.18 TTL / f 4.07 3.45 4.25 OBFL / TTL 0.23 0.18 0.45

[0139] Table 11 Design values ​​of optical physical parameters of an imaging lens

[0140]

[0141] The surface numbers in Table 11 are numbered according to the order of the surfaces of each lens. "S1" represents the object surface of the first lens, "S2" represents the image surface of the first lens, and so on. "PL" represents a plane; "STO" represents the aperture of the lens; the radius of curvature represents the curvature of the lens surface, a positive value represents that the surface is bent toward the image side, and a negative value represents that the surface is bent toward the object side; "infinite" represents that the surface is a plane and the radius of curvature is infinite; the thickness represents the central axial distance from the current surface to the next surface, the refractive index represents the ability of the material between the current surface and the next surface to deflect light, and the space represents that the current position is air with a refractive index of 1; the Abbe constant represents the dispersion characteristics of the material between the current surface and the next surface to the light; the k value represents the numerical value of the cone coefficient of the aspheric surface; the aperture represents the aperture size of the current surface.

[0142] The aspheric cone coefficient can be defined by the following aspheric formula, but is not limited to the following representation method:

[0143]

[0144] Among them, z is the axial vector height of the aspheric surface in the Z direction; r is the height of the aspheric surface; c is the curvature of the fitted sphere, which is the inverse of the radius of curvature; k is the fitting cone coefficient; AG is the coefficient of the 4th, 6th, 8th, 10th, 12th, 14th, and 16th order terms of the aspheric polynomial.

[0145] Table 12 Aspheric coefficients of an imaging lens

[0146]

[0147] Among them, "1.2800E-04" means 1.2800*10 -4 The remaining coefficients are expressed in this way.

[0148] Based on the above parameter definitions, the optical parameters that can be achieved by the imaging lens in the fourth embodiment of the present invention are as follows: focal length f is 5.51 mm, F# is 1.60, field of view angle DFOV=66.2°, and total optical length TTL=22.39 mm.

[0149] Furthermore, Fig.14 This is a schematic diagram of the spherical aberration curve of an imaging lens provided by the fourth embodiment of the utility model. The vertical direction represents the normalization of the aperture, 0 represents the optical axis, and the pupil radius is 1.6686mm; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm). The different linear curves in the figure represent different wavelengths of system imaging (436nm, 486nm, 546nm, 588nm and 656nm respectively), as shown in FIG. Fig.14 It can be seen that the axial aberrations at different wavelengths are all controlled within the range of (-0.1mm, +0.1mm), indicating that the spherical aberration of the imaging lens at each wavelength is well controlled.

[0150] Fig.15 This is a schematic diagram of the light fan of an imaging lens provided in the fourth embodiment of the utility model. The light fan diagram is one of the most commonly used evaluation methods in modern optical design. The horizontal axis is the beam aperture, and the vertical axis is the vertical axis aberration. The most ideal curve is a straight line that coincides with the horizontal axis, indicating that all light rays converge at the same point on the image plane, and the corresponding interval on the vertical axis of the curve is the maximum dispersion range of the light beam on the ideal image plane. The light fan diagram can not only reflect the monochromatic aberrations of different wavelengths, but also indicate the size of the vertical axis chromatic aberration. By Fig.15 It can be seen that each wavelength (436nm, 486nm, 546nm, 588nm and 656nm) in each field of view is close to the horizontal axis, indicating that the vertical axis aberration of each wavelength of the system is well corrected. At the same time, there is no obvious dispersion of each wavelength, indicating that the chromatic aberration of the system is also well corrected, thereby ensuring that the optical system can achieve high-resolution imaging requirements.

[0151] Fig.16 Schematic diagram of field curvature distortion of an imaging lens provided by the fourth embodiment of the present utility model. In the coordinate system on the left side of the figure, the horizontal coordinate represents the magnitude of the field curvature, and the unit is mm; the vertical coordinate represents the normalized image height, and there is no unit; Fig.16 As can be seen from the left figure, the field curvature of the lens provided by this embodiment is effectively controlled at each wavelength (436nm, 486nm, 546nm, 588nm and 656nm), that is, when imaging, the difference between the image quality at the center and the image quality at the periphery is small. In the coordinate system on the right, the horizontal coordinate represents the size of the distortion, in %, and the vertical coordinate represents the normalized image height, without unit; Fig.16It can be seen from the figure on the right that the maximum distortion of the lens provided in this embodiment is controlled within 10%, the distortion is well corrected, the imaging distortion is small, and the difference between the image and the actual object is small.

[0152] In summary, the imaging lens provided in the fourth embodiment of the present invention adopts a mixed combination of 1 spherical glass lens and 4 aspherical plastic transparent lenses. By matching the lens materials and reasonably allocating the optical focal length of each component, it can match the 1 / 2.7″ target surface sensor, and the resolution can reach 4K image quality requirements, realizing 24-hour all-weather high-definition monitoring, and the real-life picture is clear in high and low temperature environments; the optical distortion of the lens system is smaller than that of the lenses with the same specifications and parameters on the market. At the same time, in terms of manufacturability, each lens has low sensitivity, and the lens surface is simple and easy to manufacture, which reduces the processing cost of the system; the lens system has high cost performance.

[0153] The above specific implementations do not constitute a limitation on the protection scope of the present utility model. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. An imaging lens, characterized in that: It includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are arranged in sequence from the object plane to the image plane along the optical axis; Wherein, the first lens is a negative power lens, the second lens is a positive power lens, the third lens is a positive power lens, and the fourth lens and the fifth lens both have power and opposite power; The focal power of the first lens is Φ1, the focal power of the second lens is Φ2, the focal power of the third lens is Φ3, and the focal power of the imaging lens is Φ; Among them, -0.75≤(Φ1+Φ2) / Φ≤-0.05, 0.01≤(Φ1+Φ2+Φ3) / Φ≤0.

55.

2. The imaging lens according to claim 1, characterized in that: The focal power of the fourth lens is Φ4, and the focal power of the fifth lens is Φ5; Among them, -0.65≤Φ1 / Φ≤-0.25, 0.15≤Φ2 / Φ≤0.45, 0.55≤Φ3 / Φ≤0.68, -1.50≤Φ4 / Φ≤1.50, -1.25≤Φ5 / Φ≤1.

25.

3. The imaging lens according to claim 1, wherein: The refractive index of the third lens is Nd3, and the Abbe constant of the third lens is Vd3; Among them, 1.40≤Nd3≤1.65, 75.5≤Vd3≤96.

50.

4. The imaging lens according to claim 1, wherein: The axial distance between the centers of the first lens and the second lens is TH12, the axial distance between the centers of the second lens and the third lens is TH23, and the axial distance between the centers of the third lens and the fourth lens is TH34; Among them, 1.55≤TH12≤5.50mm; 0.05≤TH23≤1.85mm; 0.05≤TH34≤1.25mm.

5. The imaging lens according to claim 1, wherein: The center thickness of the first lens is CT1, and the center thickness of the second lens is CT2; Among them, 0.65≤CT1≤2.45, 1.45≤CT2≤2.

85.

6. The imaging lens according to claim 1, wherein: The total image height of the imaging lens is IC, the total optical length of the imaging lens is TTL, the total focal length of the imaging lens is f, and the optical back focus of the imaging lens is OBFL; Among them, 0.13≤IC / TTL≤0.18; 3.45≤TTL / f≤4.25; 0.18≤OBFL / TTL≤0.

45.

7. The imaging lens according to claim 1, characterized in that: The first lens comprises a first object-side surface close to the object plane and a first image-side surface close to the image plane, the first object-side surface is a concave surface, and the first image-side surface is a concave surface; The second lens comprises a second image-side surface close to the image plane, and the second image-side surface is a convex surface; The third lens comprises a third object-side surface close to the object plane and a third image-side surface close to the image plane, the third object-side surface is a convex surface or a plane, and the third image-side surface is a convex surface; The fourth lens includes a fourth image-side surface close to the image plane, and the fifth lens includes a fifth object-side surface close to the object plane and a fifth image-side surface close to the image plane; the fourth image-side surface is a concave surface, the fifth object-side surface is a convex surface, and the fifth image-side surface is a convex surface; or, the fourth image-side surface is a convex surface, the fifth object-side surface is a concave surface, and the fifth image-side surface is a convex surface.

8. The imaging lens according to claim 1, wherein: The first lens, the second lens, the fourth lens and the fifth lens are all plastic aspherical lenses; The third lens is a glass spherical lens.

9. The imaging lens according to claim 1, wherein: The imaging lens also includes an aperture stop and a filter; The aperture stop is disposed in the optical path between the second lens and the third lens; or, the aperture stop is disposed in the optical path between the third lens and the fourth lens; The filter is arranged in the optical path between the fifth lens and the image plane.

10. The imaging lens according to claim 1, wherein: The aperture number of the imaging lens is F#; Among them, 1.52≤F#≤1.65.

Images