Optical lens, camera module and endoscope

Abstract

The invention discloses an optical lens, a camera module and an endoscope, the optical lens comprises four lenses with refractive power, the optical lens comprises a first lens, an optical filter, a second lens, a third lens and a fourth lens which are sequentially arranged in the direction from the object side to the image side of an optical axis, the first lens has negative refractive power, and the fourth lens has negative refractive power. The image side surface of the first lens is a concave surface near the optical axis; the second lens has positive refractive power, and the object side surface of the second lens is a convex surface near the optical axis; the third lens has positive refractive power, and the object side surface of the third lens is a convex surface near the optical axis; the fourth lens has negative refractive power, the object side surface of the fourth lens is a concave surface near the optical axis, and the optical lens meets the following relational expressions: 110default; a FOVlt; 155 deg and 1.7 lt are included; and TTL / ImgHlt; and 2.7. According to the optical lens, the camera module and the endoscope disclosed by the invention, the requirement of a large field angle can be met on the basis of considering the miniaturization design.

Description

Technical Field

[0001] This application relates to the field of optical imaging technology, and particularly relates to an optical lens, a camera module, and an endoscope. Background Art

[0002] A medical endoscope is mainly an auxiliary medical device that passes a tube equipped with a camera module into the human body to improve the diagnostic accuracy by taking images of the internal human body. In related technologies, considering that the endoscope usually needs to be inserted into the human body, in order to minimize the harm to the patient as much as possible, it is usually required that the endoscope has good insertability. That is, the outer diameter of the head end of the endoscope should be small, the length of the bending hard end should be short, and the viewing range should be large. In other words, it is required that the endoscope should have the characteristics of a compact structure and a large field of view. Therefore, how to balance the structural compactness and the large field of view of the endoscope is an urgent problem to be solved. Summary of the Invention

[0003] Embodiments of this application disclose an optical lens, a camera module, and an endoscope, which can effectively balance the requirements of the endoscope for a compact structure and a large field of view.

[0004] To achieve the above object, in the first aspect, there are a total of four lenses with refractive power, and the optical lens includes, in order along the object side to the image side direction of the optical axis:

[0005] A first lens, the first lens has negative refractive power, and the image side surface of the first lens is concave near the optical axis;

[0006] A filter;

[0007] A second lens, the second lens has positive refractive power, and the object side surface of the second lens is convex near the optical axis;

[0008] A third lens, the third lens has positive refractive power, and the object side surface of the third lens is convex near the optical axis;

[0009] A fourth lens, the fourth lens has negative refractive power, and the object side surface of the fourth lens is concave near the optical axis;

[0010] The optical lens satisfies the following relational expression:

[0011] 110deg < FOV < 155deg and 1.7 < TTL / ImgH < 2.7;

[0012] Wherein, FOV is the maximum field of view angle of the optical lens, TTL is the distance from the object side surface of the first lens to the imaging surface of the optical lens on the optical axis, and ImgH is half of the image height corresponding to the maximum field of view angle of the optical lens.

[0013] As an optional implementation manner, the optical lens satisfies the following relational expressions:

[0014] -1.4 < f1 / f < -0.6, and / or, 1.2 < f2 / f < 4, and / or, 0.5 < f3 / f < 1.1, and / or, -2 < f4 / f < -0.8;

[0015] Wherein, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, and f is the focal length of the optical lens.

[0016] As an optional implementation manner, the optical lens satisfies the following relational expressions:

[0017] 0.7 < |R11| / f, and / or, 0.3 < R12 / f, and / or, 0.6 < R21 / f < 2, and / or, 9 < |R22| / f, and / or, 0.5 < R31 / f < 1.0, and / or, -1.1 < R32 / f < -0.4, and / or, -1.3 < R41 / f < -0.4, and / or, 3 < |R42| / f, and / or, -1.7 < R31 / R32 < -0.6;

[0018] Wherein, R11 is the curvature radius of the object side surface of the first lens at the optical axis, R12 is the curvature radius of the image side surface of the first lens at the optical axis, R21 is the curvature radius of the object side surface of the second lens at the optical axis, R22 is the curvature radius of the image side surface of the second lens at the optical axis, R31 is the curvature radius of the object side surface of the third lens at the optical axis, R32 is the curvature radius of the image side surface of the third lens at the optical axis, R41 is the curvature radius of the object side surface of the fourth lens at the optical axis, R42 is the curvature radius of the image side surface of the fourth lens at the optical axis, and f is the focal length of the optical lens.

[0019] As an optional implementation manner, the optical lens satisfies the following relational expressions:

[0020] 2.5 < TD / ΣAT < 3.5, and / or, 2.5 < TTL / f < 5.5, and / or, 1.2 < ImgH / f < 2.3, and / or, 2.2 < TTL / BL < 3;

[0021] Wherein, TTL is the distance on the optical axis from the object side surface of the first lens to the imaging surface of the optical lens, ImgH is half of the image height corresponding to the maximum field of view angle of the optical lens, TD is the distance on the optical axis from the object side surface of the first lens to the image side surface of the fourth lens, ΣAT is the sum of the distances on the optical axis between the image side surface of the first lens and the object side surface of the filter, the image side surface of the filter and the object side surface of the second lens, the image side surface of the second lens and the object side surface of the third lens, and the image side surface of the third lens and the object side surface of the fourth lens, f is the focal length of the optical lens, and BL is the distance on the optical axis from the image side surface of the fourth lens to the imaging surface of the optical lens.

[0022] As an alternative embodiment, the optical lens satisfies the following relational expressions:

[0023] 3 < FNO < 5, and / or, 26deg < FOV / FNO < 40deg;

[0024] Wherein, FNO is the f-number of the optical lens.

[0025] As an alternative embodiment, the optical lens satisfies the following relational expressions:

[0026] 0.9 < CT3 / CT4 < 2.1, and / or, 1 < ET1 / CT1 < 1.9, and / or, 1 < ET4 / CT4 < 2.1, and / or, 6 < AT12 / AT34 < 22; and / or, 1 < SD11 / SD42 < 1.3, and / or, 0.8 < SD22 / SD31 < 1, and / or, 0.4 < SD11 / ImgH < 0.6;

[0027] Wherein, CT3 is the thickness of the third lens on the optical axis, CT4 is the thickness of the fourth lens on the optical axis, ET1 is the distance in the direction parallel to the optical axis from the maximum effective semi-aperture of the object side surface of the first lens to the maximum effective semi-aperture of the image side surface of the first lens, ET4 is the distance in the direction parallel to the optical axis from the maximum effective semi-aperture of the object side surface of the fourth lens to the maximum effective semi-aperture of the image side surface of the fourth lens, AT12 is the sum of the distances on the optical axis between the image side surface of the first lens and the object side surface of the filter, and the image side surface of the filter and the object side surface of the second lens, AT34 is the distance on the optical axis between the image side surface of the third lens and the object side surface of the fourth lens, SD11 is the maximum effective semi-aperture of the object side surface of the first lens, SD42 is the maximum effective semi-aperture of the image side surface of the fourth lens, SD22 is the maximum effective semi-aperture of the image side surface of the second lens, and SD31 is the maximum effective semi-aperture of the object side surface of the third lens.

[0028] As an alternative implementation, the optical lens satisfies the following relational expressions:

[0029] 0.5 < (|SAG11| + |SAG12|) / CT1 < 1.5, and / or, 0.1 < (|SAG21| + |SAG22|) / CT2 < 0.4, and / or, 0.1 < (|SAG31| + |SAG32|) / CT3 < 0.9, and / or, 0.3 < (|SAG41| + |SAG42|) / CT4 < 1, and / or, -14 < f4 / |SAGY41| < -3, and / or, f4 / |SAGY42| < -10;

[0030] Wherein, CT1 is the thickness of the first lens on the optical axis, SAG11 is the distance in the optical axis direction from the maximum effective semi-aperture of the object side of the first lens to the intersection of the object side of the first lens and the optical axis, SAG12 is the distance in the optical axis direction from the maximum effective semi-aperture of the image side of the first lens to the intersection of the image side of the first lens and the optical axis, SAG21 is the distance in the optical axis direction from the maximum effective semi-aperture of the object side of the second lens to the intersection of the object side of the second lens and the optical axis, SAG22 is the distance in the optical axis direction from the maximum effective semi-aperture of the image side of the second lens to the intersection of the image side of the second lens and the optical axis, SAG31 is the distance in the optical axis direction from the maximum effective semi-aperture of the object side of the third lens to the intersection of the object side of the third lens and the optical axis, SAG32 is the distance in the optical axis direction from the maximum effective semi-aperture of the image side of the third lens to the intersection of the image side of the third lens and the optical axis, SAG41 is the distance in the optical axis direction from the maximum effective semi-aperture of the object side of the fourth lens to the intersection of the object side of the fourth lens and the optical axis, SAG42 is the distance in the optical axis direction from the maximum effective semi-aperture of the image side of the fourth lens to the intersection of the image side of the fourth lens and the optical axis, CT2 is the thickness of the second lens on the optical axis, CT3 is the thickness of the third lens on the optical axis, and CT4 is the thickness of the fourth lens on the optical axis.

[0031] As an alternative implementation, the optical lens further includes a diaphragm, the diaphragm is located between the filter and the object side of the second lens, and / or, the optical lens further includes a protective glass, the protective glass is disposed between the image side of the fourth lens and the imaging surface of the optical lens.

[0032] In a second aspect, the present application discloses an imaging module, the imaging module includes an image sensor and the optical lens as described in the first aspect above, and the image sensor is disposed on the image side of the optical lens. The imaging module with the above optical lens can meet the requirement of a large field of view on the basis of taking into account the miniaturized design.

[0033] In a third aspect, the present application discloses an endoscope, which includes a tube body and the imaging module as described in the second aspect above, and the imaging module is disposed in the tube body. The endoscope with the above imaging module can meet the requirement of a large field of view angle on the basis of taking into account the miniaturized design.

[0034] Compared with the prior art, the beneficial effects of the present application are as follows:

[0035] In the optical lens provided by the present application, in order to achieve a large field of view angle on the basis of realizing the miniaturized design. The present application realizes the aperture change from a large aperture to a small aperture by providing a lens with four refractive powers and, at the same time, disposing a filter between the first lens and the second lens. On this basis, the present application also designs the refractive powers and surface shapes of the four lenses, that is, by using four lenses with refractive powers, the pressure of refracting light can be dispersed to each lens, so as to reduce the task amount of a single lens refracting light and avoid the lens being too bent to increase the tolerance sensitivity. Specifically, the first lens has a negative refractive power, and with the design that its image side surface is concave at the near optical axis, it is beneficial to the incidence and convergence of light in a large field of view range, and at the same time, the optical lens can have a smaller head aperture; the second lens has a positive refractive power, and the object side surface of the second lens is convex at the near optical axis, which can effectively correct the aberration generated by the first lens and improve the imaging quality of the optical lens. The third lens has a positive refractive power, and its object side surface is convex at the near optical axis, which is beneficial to reducing the incident angle of light entering the optical lens, so that as much light as possible enters the optical lens. The fourth lens has a negative refractive power, and the object side surface is concave at the near optical axis, which is beneficial to correcting the spherical aberration, coma aberration and distortion generated by the first lens, the second lens and the third lens, and further improving the imaging quality of the optical lens.

[0036] In addition, when the optical lens satisfies the relational expressions 110deg < FOV < 155deg and 1.7 < TTL / ImgH < 2.7, the optical lens can have the effect of imaging with a large viewing angle while realizing the miniaturized design, which is beneficial to improving the imaging quality of the optical lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to these drawings.

[0038] Figure 1A It is a schematic structural diagram of the optical lens disclosed in the first embodiment of the present application;

[0039] Figure 1B is a schematic diagram of the structure of each lens disclosed in the first embodiment of the present application;

[0040] Figure 2 is a longitudinal spherical aberration graph (mm), an astigmatism curve graph (mm), and a distortion curve graph (%) of the optical lens disclosed in the first embodiment of the present application;

[0041] Figure 3 is a schematic structural diagram of an optical lens disclosed in the second embodiment of the present application;

[0042] Figure 4 is a longitudinal spherical aberration graph (mm), an astigmatism curve graph (mm), and a distortion curve graph (%) of the optical lens disclosed in the second embodiment of the present application;

[0043] Figure 5 is a schematic structural diagram of an optical lens disclosed in the third embodiment of the present application;

[0044] Figure 6 is a longitudinal spherical aberration graph (mm), an astigmatism curve graph (mm), and a distortion curve graph (%) of the optical lens disclosed in the third embodiment of the present application;

[0045] Figure 7 is a schematic structural diagram of an optical lens disclosed in a fourth embodiment of the present application;

[0046] Figure 8 is a longitudinal spherical aberration graph (mm), an astigmatism curve graph (mm), and a distortion curve graph (%) of the optical lens disclosed in the fourth embodiment of the present application;

[0047] Fig. 9 is a schematic structural diagram of an optical lens disclosed in a fifth embodiment of the present application;

[0048] Fig.10 is a longitudinal spherical aberration graph (mm), an astigmatism curve graph (mm), and a distortion curve graph (%) of the optical lens disclosed in the fifth embodiment of the present application;

[0049] Fig.11 It is a structural schematic diagram of the camera module disclosed in this application;

[0050] Fig.12 It is a schematic diagram of the structure of the endoscope disclosed in this application. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0052] In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, "plurality" means two or more.

[0053] The technical solution of the present application will be further described below in conjunction with embodiments and drawings.

[0054] Please also read Figure 1A , Figure 1B According to the first aspect of the present application, the present application discloses an optical lens 100, which has a total of four lenses with refractive power, and along the direction from the object side to the image side of the optical axis, it includes: a first lens L1, a filter IR, a second lens L2, a third lens L3 and a fourth lens L4.

[0055] Optionally, the first lens L1 has a negative refractive power, which helps to compress the length of the optical axis of the lens group of the optical lens 100 near the object side, thereby reducing the thickness of the entire optical lens 100 in the direction of the optical axis near the object side, and is also conducive to reducing the head size of the first lens L1. The object side surface S1 of the first lens L1 can be convex or concave at the near optical axis, so that the surface shape of the object side surface S1 of the first lens L1 can be adjusted, thereby enhancing the light path control ability of the light incident surface of the first lens L1. The image side surface S2 of the first lens L1 is concave at the near optical axis, so that the surface shape of the image side surface of the first lens L1 can also be adjusted, which helps to correct aberrations such as astigmatism.

[0056] Optionally, the second lens L2 may have a positive refractive power, so as to balance the aberrations generated by the lens group for compressing the optical lens 100. The object-side surface S3 of the second lens L2 may be a convex surface at the near optical axis, and the image-side surface S4 of the second lens L2 may be a convex surface or a concave surface at the near optical axis, so as to adjust the traveling direction of the light, which helps to balance the volume configuration of the lens group of the optical lens 100 at the object side end, and also can balance the aberrations generated by the first lens L1, which helps to improve the imaging quality of the optical lens 100.

[0057] Optionally, the third lens L3 may have positive refractive power, so that it can cooperate with the second lens L2 and the first lens L1 to reduce the coma of the peripheral field of view. The object side surface S5 of the third lens L3 is convex at the near optical axis, and the image side surface S6 of the third lens L3 is concave or convex at the near optical axis, which can help adjust the surface shape of the third lens L3, thereby helping to adjust the direction of light travel and help to increase the imaging surface.

[0058] Optionally, the fourth lens L4 may have a negative refractive power, so as to balance the aberrations generated by the optical lens. The object side surface S7 of the fourth lens L4 may be a concave surface at the near optical axis, and the image side surface S8 of the fourth lens L4 may be a convex or concave surface at the near optical axis, so as to facilitate the adjustment of the surface shape of the fourth lens L4, thereby helping to improve the focusing performance of the central field of view.

[0059] It is understandable that the present application only provides a preferred solution regarding the refractive power and surface design of each lens of the optical lens 100. In other embodiments, the surface design and refractive power distribution of the optical lens 100 may also adopt other solutions, which cannot be fully listed here due to space constraints, and any other arbitrary combination is also feasible.

[0060] It is understandable that the filter IR is disposed between the first lens L1 and the second lens L2, and the filter IR may be an infrared cutoff filter. The infrared cutoff filter can filter out infrared light, improve the imaging quality, and make the imaging more in line with the visual experience of the human eye. It is understandable that the filter IR may be made of optical glass coating, or may be made of colored glass, or a filter IR of other materials, which may be selected according to actual needs and is not specifically limited in this embodiment.

[0061] Optionally, the optical lens 100 further includes a stop STO, which may be an aperture stop and / or a field stop, and may be disposed between the filter IR and the object side surface S3 of the second lens L2. Thus, it is possible to achieve an aperture change from a large aperture to a small aperture, and to achieve aperture adjustment of the optical lens 100. It is understandable that, in other embodiments, the stop STO may also be disposed between the other two lenses, for example, the stop STO may also be disposed between the second lens L2 and the third lens L3, and the specific setting may be adjusted according to actual conditions, and this embodiment does not specifically limit this.

[0062] Optionally, the optical lens 100 further includes a protective glass CG, which may be disposed between the image-side surface S8 of the fourth lens L4 and the imaging surface IMG of the optical lens 100 .

[0063] In some embodiments, the optical lens 100 can be applied to an endoscope. Therefore, the materials of the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 can be selected as plastics to achieve the lightweight of the optical lens 100 while being more conducive to the machining of the complex surface of the lens.

[0064] In some embodiments, the optical lens 100 satisfies the following relationship: 110deg < FOV < 155deg; where FOV is the maximum field of view angle of the optical lens 100. When the optical lens 100 satisfies the relationship 120deg < FOV < 155deg, the optical lens 100 can have the characteristic of a large field of view angle, thereby achieving large field of view angle imaging. Optionally, the relationship can further satisfy 120deg < FOV < 150deg, so that the large field of view angle characteristic of the optical lens is more prominent.

[0065] In some embodiments, the optical lens 100 satisfies the relationship: 26deg < FOV / FNO < 40deg, where FNO is the f-number of the optical lens 100. In this way, the optical lens 100 can have the characteristics of a large aperture while taking into account the large field of view angle, that is, it can achieve a balance between illuminance and depth of field and enhance the light input to improve the image quality. Optionally, the relationship can further satisfy 28deg < FOV / FNO < 38deg.

[0066] In some embodiments, the optical lens 100 satisfies the relationship: 3 < FNO < 5. Thus, the optical lens 100 can have sufficient light input to meet the characteristics of a large aperture. Optionally, the relationship can further satisfy 3.4 < FNO < 4.7, so that the large aperture characteristic of the optical lens is more obvious.

[0067] In some embodiments, the optical lens 100 satisfies the following relationship: 2.2 < TTL / BL < 3. Where BL is the distance from the image side S8 of the fourth lens L4 to the imaging surface IMG of the optical lens 100 on the optical axis (i.e., the back focal length of the optical lens), and TTL is the distance from the object side S1 of the first lens L1 to the imaging surface IMG of the optical lens 100 on the optical axis (i.e., the total length of the optical lens 100). When the optical lens 100 satisfies the relationship 2.2 < TTL / BL < 3, it can effectively control the back focal length of the optical lens 100 and avoid the situation that the back focal length of the optical lens 100 is too large, resulting in the compression of the lens space of the optical lens 100. Optionally, the relationship can further be 2.4 < TTL / BL < 2.8, so that the back focal length of the optical lens 100 is appropriate, thereby enabling the optical lens to have sufficient lens space.

[0068] In some embodiments, the optical lens 100 satisfies the following relationship: 2.5 < TTL / f < 5.5. Wherein, f is the focal length of the optical lens 100. In this way, while further realizing the miniaturized design of the optical lens, the optical lens 100 can also have a high imaging quality. Optionally, this relationship can further be 3 < TTL / f < 5, which is further beneficial to the improvement of the imaging quality of the optical lens.

[0069] In some embodiments, the optical lens 100 satisfies the relationship: 1.7 < TTL / ImgH < 2.7, where ImgH is half of the image height corresponding to the maximum field of view angle of the optical lens 100. By defining the ratio of the total length of the optical lens 100 to half of the image height corresponding to the maximum field of view angle of the optical lens 100, while realizing the miniaturized design, the optical lens 100 can have a good imaging effect. Optionally, this relationship can further be 1.9 < TTL / ImgH < 2.5, so that the optical lens can better balance the miniaturized design and good imaging quality.

[0070] In some embodiments, the optical lens 100 satisfies the relationship: 1.2 < ImgH / f < 2.3. By defining the ratio of half of the image height corresponding to the maximum field of view angle of the optical lens to the focal length of the optical lens 100, the ratio of the height of the optical lens 100 to the imaging surface IMG of the optical lens 100 can be within a small range, so that through a reasonable structural layout, the miniaturization of the optical lens 100 can be realized. Optionally, this relationship can further satisfy 1.4 < ImgH / f < 2.1, which is further beneficial to the miniaturized design of the optical lens 100.

[0071] In some embodiments, the optical lens 100 satisfies the following relationship: -1.4 < f1 / f < -0.6, where f1 is the focal length of the first lens L1 and f is the focal length of the optical lens 100. By controlling the ratio of the focal length of the first lens L1 to the focal length of the optical lens 100, a reasonable refractive power distribution can be achieved for the first lens L1, which is beneficial to the convergence of light. At the same time, it helps to reduce the overall spherical aberration, chromatic aberration, and distortion of the first lens L1 to a reasonable position, reduce the design difficulty of the subsequent lenses, and improve the overall resolution of the optical lens 100 and strengthen the peripheral aberration correction of the optical lens 100. In addition, it is beneficial to the size compression of the first lens L1, thereby contributing to the formation of a small-sized optical lens 100. Optionally, this relationship further satisfies -1.3 < f1 / f < -0.7, which is further beneficial to the size compression of the optical lens 100.

[0072] In some embodiments, the optical lens 100 satisfies the following relationship: 1.2 < f2 / f < 4, where f2 is the focal length of the second lens L2. By controlling the ratio of the focal length of the second lens L2 to the focal length of the optical lens 100, the second lens L2 can have a reasonable refractive power, thereby reducing the angle of the light incident from the first lens L1. At the same time, it is beneficial to improve the overall resolution of the optical lens 100 and strengthen the peripheral aberration correction of the optical lens 100. Optionally, the relationship can further satisfy 1.6 < f2 / f < 3.5, which is further beneficial to improving the imaging quality of the optical lens 100.

[0073] In some embodiments, the optical lens 100 satisfies the following relationship: 0.5 < f3 / f < 1.1, where f3 is the focal length of the third lens L3. By controlling the ratio of the focal length of the third lens L3 to the focal length of the optical lens 100, the third lens L3 can have a reasonable refractive power, further reducing the angle of the light incident from the first lens L1. At the same time, it can improve the overall resolution of the optical lens 100 and strengthen the peripheral aberration correction of the optical lens 100. Optionally, the relationship further satisfies 0.65 < f3 / f < 0.95, which is further beneficial to improving the imaging quality of the optical lens 100.

[0074] In some embodiments, the optical lens 100 satisfies the following relationship: -2 < f4 / f < -0.8, where f4 is the focal length of the fourth lens L4. By controlling the ratio of the focal length of the fourth lens L4 to the focal length of the optical lens 100, the fourth lens L4 can have a reasonable refractive power, helping to correct the aberrations introduced by the first lens L1, the second lens L2, and the third lens L3, thereby being beneficial to improving the imaging quality of the optical lens 100. Optionally, the relationship further satisfies -1.7 < f4 / f < -1, which is further beneficial to improving the imaging quality of the optical lens 100.

[0075] In some embodiments, the optical lens 100 satisfies the following relationship: 0.7 < |R11| / f; where R11 is the curvature radius of the object side surface S1 of the first lens L1 at the optical axis. When the optical lens 100 satisfies the relationship 0.7 < |R11| / f, the surface type complexity of the first lens L1 can be reduced, thereby effectively suppressing the increase of field curvature and distortion. At the same time, it can reduce the forming difficulty of the first lens L1 and is beneficial to controlling the size of the first lens L1.

[0076] In some embodiments, the optical lens 100 satisfies the following relational expression: 0.3 < R12 / f; where R12 is the curvature radius of the image side surface S2 of the first lens L1 on the optical axis. When the optical lens 100 satisfies the relational expression 0.3 < R12 / f, the surface type complexity of the first lens L1 can be reduced, thereby effectively suppressing the increase of field curvature and distortion, and at the same time reducing the forming difficulty of the first lens L1. Optionally, the relational expression can further satisfy 0.4 < R12 / f < 5, which is more beneficial to the forming of the first lens L1.

[0077] In some embodiments, the optical lens 100 satisfies the following relational expression: 0.6 < R21 / f < 2, where R21 is the curvature radius of the object side surface S3 of the second lens L2 on the optical axis. When the optical lens 100 satisfies this relational expression, the surface type complexity of the second lens L2 can be reduced, thereby effectively suppressing the increase of field curvature and distortion, and at the same time reducing the forming difficulty of the second lens L2. Optionally, the relational expression can further satisfy 0.8 < R21 / f < 1.7, further reducing the forming difficulty of the second lens L2.

[0078] In some embodiments, the optical lens 100 satisfies the following relational expression: 9 < |R22| / f, where R22 is the curvature radius of the image side surface S4 of the second lens L2 on the optical axis. When the optical lens 100 satisfies this relational expression, the surface type complexity of the second lens L2 can be reduced, thereby effectively suppressing the increase of field curvature and distortion, and at the same time reducing the forming difficulty of the second lens L2.

[0079] In some embodiments, the optical lens 100 satisfies the following relational expression: 0.5 < R31 / f < 1.0, where R31 is the curvature radius of the object side surface of the third lens L3 on the optical axis. When the optical lens 100 satisfies this relational expression, the surface type complexity of the third lens L3 can be reduced, thereby effectively suppressing the increase of field curvature and distortion, and at the same time reducing the forming difficulty of the third lens L3. Optionally, the relational expression can further satisfy 0.6 < R31 / f < 0.95, which is further beneficial to reducing the forming difficulty of the third lens L3.

[0080] In some embodiments, the optical lens 100 satisfies the following relational expression: -1.1 < R32 / f < -0.4, where R32 is the curvature radius of the image side surface of the third lens L3 on the optical axis. When the optical lens 100 satisfies this relational expression, the surface type complexity of the third lens L3 can be reduced, thereby effectively suppressing the increase of field curvature and distortion, and at the same time reducing the forming difficulty of the third lens L3. Optionally, the relational expression can further satisfy -0.95 < R32 / f < -0.5, which is further beneficial to reducing the forming difficulty of the third lens L3.

[0081] In some embodiments, the optical lens 100 satisfies the following relationship: -1.3 < R41 / f < -0.4, where R41 is the curvature radius of the object side surface S7 of the fourth lens L4 on the optical axis. When the optical lens 100 satisfies this relationship, the surface type complexity of the fourth lens L4 can be reduced, thereby effectively suppressing the increase of field curvature and distortion, and at the same time reducing the molding difficulty of the fourth lens L4. Optionally, this relationship can further satisfy -1.2 < R41 / f < -0.5, which is beneficial to the molding of the fourth lens L4.

[0082] In some embodiments, the optical lens 100 satisfies the following relationship: 3 < |R42| / f, where R42 is the curvature radius of the image side surface S8 of the fourth lens L4 on the optical axis. When the optical lens 100 satisfies this relationship, the surface type complexity of the fourth lens L4 can be reduced, thereby effectively suppressing the increase of field curvature and distortion, and at the same time reducing the molding difficulty of the fourth lens L4.

[0083] In some embodiments, the optical lens 100 satisfies the following relationship: -2.3 < R11 / R12 < 100. By limiting the ratio of the curvature radius of the object side surface S1 of the first lens L1 and the curvature radius of the image side surface S2 of the first lens L1 near the optical axis, the surface type bending condition of the first lens L1 can be reasonably controlled, thereby facilitating the processing of the first lens L1 and being beneficial to improving the processing yield of the optical lens 100.

[0084] In some embodiments, the optical lens 100 satisfies the following relationship: 7 < |R22 / R21| < 30. By limiting the ratio of the curvature radius of the object side surface S3 of the second lens L2 and the curvature radius of the image side surface S4 of the second lens L2 near the optical axis, the surface type bending condition of the second lens L2 can be reasonably controlled, thereby facilitating the processing of the second lens L2 and being beneficial to improving the processing yield of the optical lens 100.

[0085] In some embodiments, the optical lens 100 satisfies the following relationship: -1.7 < R31 / R32 < -0.6. By limiting the ratio of the curvature radius of the object side surface and the curvature radius of the image side surface of the third lens L3 near the optical axis, the surface type bending condition of the third lens L3 can be reasonably controlled, thereby facilitating the processing of the third lens L3 and being beneficial to improving the processing yield of the optical lens 100. In addition, the astigmatism introduced by the first lens L1 and the second lens L2 can be further corrected, so that the light rays in the entire field of view of the optical lens 100 can be refracted at a smaller angle. Optionally, this relationship can further satisfy -1.4 < R31 / R32 < -0.8, which is further beneficial to the refraction of light rays.

[0086] In some embodiments, the optical lens 100 satisfies the following relationship: 4<|R42 / R41|. By limiting the ratio of the radius of curvature of the object side surface S7 of the fourth lens L4 and the image side surface S8 of the fourth lens L4 at the near optical axis, the surface curvature of the fourth lens L4 can be reasonably controlled, thereby facilitating the processing of the fourth lens L4 and improving the processing yield of the optical lens 100.

[0087] In some embodiments, the optical lens 100 satisfies the following relationship: 0.5<(|SAG11|+|SAG12|) / CT1<1.5. Wherein, CT1 is the thickness of the first lens L1 on the optical axis, SAG11 is the distance from the maximum effective semi-aperture of the object side surface S1 of the first lens L1 to the intersection of the object side surface S1 of the first lens L1 and the optical axis in the direction of the optical axis (the sagittal height of the object side surface S1 of the first lens L1), and SAG12 is the distance from the maximum effective semi-aperture of the image side surface S2 of the first lens L1 to the intersection of the image side surface S2 of the first lens L1 and the optical axis in the direction of the optical axis (i.e., the sagittal height of the image side surface S2 of the first lens L1). When the optical lens satisfies this relationship, it is easy to control the refractive power and thickness of the first lens L1, thereby avoiding the first lens L1 from being too thick or too thin, and facilitating the processing of the first lens. At the same time, the incident angle of light on the first lens L1 can also be reduced, thereby reducing the sensitivity of the optical lens 100. Optionally, the relationship may further satisfy 0.55<(|SAG11|+|SAG12|) / CT1<1.3, which is more convenient for processing the first lens L1.

[0088] In some embodiments, the optical lens 100 satisfies the following relationship: 0.1<(|SAG21|+|SAG22|) / CT2<0.4. Wherein, CT2 is the thickness of the second lens L2 on the optical axis, SAG21 is the distance from the maximum effective semi-aperture of the object side surface S3 of the second lens L2 to the intersection of the object side surface S3 of the second lens L2 and the optical axis in the optical axis direction (the sagittal height of the object side surface S3 of the second lens L2), and SAG22 is the distance from the maximum effective semi-aperture of the image side surface S4 of the second lens L2 to the intersection of the image side surface S4 of the second lens L2 and the optical axis in the optical axis direction (i.e., the sagittal height of the image side surface S4 of the second lens L2). When the optical lens satisfies this relationship, it is easy to control the refractive power and thickness of the second lens L2, thereby avoiding the second lens L2 from being too thick or too thin, and facilitating the processing of the second lens. At the same time, the incident angle of light on the second lens L2 can also be reduced, thereby reducing the sensitivity of the optical lens 100. Optionally, the relationship may further satisfy 0.16<(|SAG21|+|SAG22|) / CT2<0.3, thereby making it easier to process the second lens L2.

[0089] In some embodiments, the optical lens 100 satisfies the following relationship: 0.1<(|SAG31|+|SAG32|) / CT3<0.9. Wherein, CT3 is the thickness of the third lens L3 on the optical axis, SAG11 is the distance from the maximum effective semi-aperture of the object side surface S5 of the third lens L3 to the intersection of the object side surface S5 of the third lens L3 and the optical axis in the direction of the optical axis (the sagittal height of the object side surface S5 of the third lens L3), and SAG32 is the distance from the maximum effective semi-aperture of the image side surface S6 of the third lens L3 to the intersection of the image side surface S6 of the third lens L3 and the optical axis in the direction of the optical axis (i.e., the sagittal height of the image side surface S6 of the third lens L3). When the optical lens satisfies this relationship, it is easy to control the refractive power and thickness of the third lens L3, thereby preventing the third lens L3 from being too thick or too thin, and facilitating the processing of the third lens L3. At the same time, it is also helpful to reduce the distortion and field curvature generated by correcting the first lens L1 and the second lens L2, so that the refractive power of the imaging surface IMG close to the optical lens 100 is more uniform. Optionally, the relationship can further satisfy 0.2<(|SAG31|+|SAG32|) / CT3<0.8, so that the third lens L3 is easier to process.

[0090] In some embodiments, the optical lens 100 satisfies the following relationship: 0.3<(|SAG41|+|SAG42|) / CT4<1. Wherein, CT4 is the thickness of the fourth lens L4 on the optical axis, SAG41 is the distance from the maximum effective semi-aperture of the object side surface S7 of the fourth lens L4 to the intersection of the object side surface S7 of the fourth lens L4 and the optical axis in the optical axis direction (the sagittal height of the object side surface S7 of the fourth lens L4), and SAG42 is the distance from the maximum effective semi-aperture of the image side surface S8 of the fourth lens L4 to the intersection of the image side surface S8 of the fourth lens L4 and the optical axis in the optical axis direction (i.e., the sagittal height of the image side surface S8 of the fourth lens L4). When the optical lens satisfies this relationship, it is easy to control the thickness and refractive power of the fourth lens L4, so that the thickness of the fourth lens L4 is controllable, thereby facilitating the processing and molding of the fourth lens L4. At the same time, it can also effectively reduce the incident angle of light on the imaging surface IMG of the optical lens 100, thereby reducing the sensitivity of the optical lens 100, and is conducive to correcting the distortion and field curvature generated by the first lens L1, the second lens L2, and the third lens L3, so that the refractive power close to the optical lens 100 is more uniform. Optionally, the relationship can further satisfy 0.35<(|SAG41|+|SAG42|) / CT4<0.9, so that it is easier to process the fourth lens L4.

[0091] In some embodiments, the optical lens 100 satisfies the following relationship: -14 < f4 / |SAGY41| < -3. When the optical lens satisfies this relationship, the refractive power and shape of the fourth lens L4 can be made reasonable, so that chromatic aberration and spherical aberration can be minimized, which is beneficial to improving the imaging quality of the optical lens. At the same time, through reasonable refractive power distribution, the light-gathering ability of the optical lens 100 can be strengthened and it is beneficial to control the size of the optical lens 100. Optionally, this relationship can further satisfy -12 < f4 / |SAGY41| < -4, which is further convenient for controlling the size of the optical lens 100.

[0092] In some embodiments, the optical lens 100 satisfies the following relationship: f4 / |SAGY42| < -10. When the optical lens satisfies this relationship, the refractive power and shape of the fourth lens L4 can be made reasonable, so that chromatic aberration and spherical aberration can be minimized, which is beneficial to improving the imaging quality of the optical lens. At the same time, through reasonable refractive power distribution, the light-gathering ability of the optical lens 100 can be strengthened and it is beneficial to control the size of the optical lens 100. Optionally, this relationship can further satisfy f4 / |SAGY42| < -16, which is further convenient for controlling the size of the optical lens 100.

[0093] In some embodiments, the optical lens 100 satisfies the following relationship: 1 < ET1 / CT1 < 1.9. Wherein, ET1 is the distance in the direction parallel to the optical axis from the maximum effective semi-aperture of the object side S1 of the first lens L1 to the maximum effective semi-aperture of the image side S2 of the first lens L1 (i.e., the edge thickness of the first lens L1). By limiting the ratio of the edge thickness of the first lens L1 to the central thickness of the first lens L1, the thickness of the first lens L1 can be reasonably controlled, realizing the miniaturized design of the optical lens 100, and at the same time being beneficial to reducing the sensitivity of the optical lens 100. Optionally, this relationship can further satisfy 1.2 < ET1 / CT1 < 1.7, which is beneficial to the miniaturized design of the optical lens 100.

[0094] In some embodiments, the optical lens 100 satisfies the following relationship: 1 < ET4 / CT4 < 2.1. Wherein, ET4 is the distance in the direction parallel to the optical axis from the maximum effective semi-aperture of the object side S7 of the fourth lens L4 to the maximum effective semi-aperture of the image side S8 of the fourth lens L4 (i.e., the edge thickness of the fourth lens L4). By limiting the ratio of the edge thickness of the fourth lens L4 to the central thickness of the fourth lens L4, the thickness of the fourth lens L4 can be reasonably controlled, realizing the miniaturized design of the optical lens 100, and at the same time being beneficial to reducing the sensitivity of the optical lens 100. Optionally, this relationship can further satisfy 1.2 < ET4 / CT4 < 1.9, which is beneficial to the miniaturized design of the optical lens 100.

[0095] In some embodiments, the optical lens 100 satisfies the following relationship: 0.9 < CT3 / CT4 < 2.1. Here, CT3 is the thickness of the third lens L3 on the optical axis (i.e., the central thickness of the third lens L3), and CT4 is the thickness of the fourth lens L4 on the optical axis (i.e., the central thickness of the fourth lens L4). When this relationship is satisfied, the thickness ratio of the third lens L3 and the fourth lens L4 can be effectively controlled, realizing the miniaturized design of the optical lens 100. At the same time, the third lens L3 and the fourth lens L4 can have better processing characteristics, which is beneficial to reducing the sensitivity of the optical lens 100. Optionally, this relationship can further satisfy 1.1 < CT3 / CT4 < 1.9, which is beneficial to the miniaturized design of the optical lens 100.

[0096] In some embodiments, the optical lens 100 satisfies the following relationship: 2.5 < TD / ΣAT < 3.5, where TD is the distance from the object side of the first lens L1 to the image side of the fourth lens L4 on the optical axis, and ΣAT is the sum of the distances on the optical axis between the image side of the first lens L1 and the object side of the filter IR, the image side of the filter IR and the object side of the second lens L2, the image side of the second lens L2 and the object side of the third lens L3, and the image side of the third lens L3 and the object side of the fourth lens L4. When this relationship is satisfied, the relationship between the thicknesses of the respective lenses and the distances between adjacent lenses can be further balanced, so that the arrangement between the respective lenses of the optical lens 100 is more compact, further reducing the total length of the optical lens 100, which is beneficial to the miniaturized design of the optical lens. Optionally, this relationship can further satisfy: 2.6 < TD / ΣAT < 3, so that the overall structure of the optical lens 100 is more compact and more beneficial to the miniaturized design.

[0097] In some embodiments, the optical lens 100 satisfies the following relationship: 6 < AT12 / AT34 < 22, where AT12 is the sum of the distances on the optical axis between the image side of the first lens and the object side of the filter, and the image side of the filter and the object side of the second lens, and AT34 is the distance on the optical axis between the image side of the third lens and the object side of the fourth lens. When this relationship is satisfied, the arrangement between the third lens L3 and the fourth lens L4 is more compact, while the arrangement between the first lens L1 and the second lens L2 is relatively loose, which is beneficial to controlling the small-angle refraction of light between the first lens and the second lens and facilitating the light collection of the optical lens. Optionally, this relationship can further satisfy 6.3 < AT12 / AT34 < 21.9.

[0098] In some embodiments, the optical lens 100 satisfies the following relationship: 1<SD11 / SD42<1.3, SD11 is the maximum effective semi-aperture of the object side of the first lens, and SD42 is the maximum effective semi-aperture of the image side of the fourth lens. When this relationship is satisfied, the aperture of the object side of the first lens L1 and the aperture of the image side of the fourth lens L4 are close, which is beneficial to improve the space utilization of the optical lens 100.

[0099] In some embodiments, the optical lens 100 satisfies the following relationship: 0.8<SD22 / SD31<1, where SD22 is the maximum effective semi-aperture of the image side surface of the second lens, and SD31 is the maximum effective semi-aperture of the object side surface of the third lens. When this relationship is satisfied, the aperture of the image side surface of the second lens L2 and the aperture of the object side surface of the third lens L3 are close, so that the step difference between the two can be reduced, making the transition of light between the two smoother.

[0100] In some embodiments, the optical lens 100 satisfies the following relationship: 0.4<SD11 / ImgH<0.6, so that the aperture of the object side of the first lens L1 is slightly smaller than the size of the imaging surface IMG, thereby reducing the head aperture of the optical lens and achieving a small head design.

[0101] The optical lens 100 of this embodiment will be described in detail below with reference to specific parameters.

[0102] First embodiment

[0103] The structural schematic diagram of the optical lens 100 disclosed in the first embodiment of the present application is as follows Figure 1A As shown, the optical lens 100 includes a first lens L1, a filter IR, an aperture STO, a second lens L2, a third lens L3, a fourth lens L4 and a protective glass CG which are arranged in sequence from the object side to the image side along the optical axis.

[0104] In this embodiment, the first lens L1 has negative refractive power, and the object side surface S1 and the image side surface S2 of the first lens L1 are both concave surfaces at the near optical axis. The second lens L2 has positive refractive power, and the object side surface S3 and the image side surface S4 of the second lens L2 are both convex surfaces at the near optical axis. The third lens L3 has positive refractive power, and the object side surface S5 and the image side surface S6 of the third lens L3 are both convex surfaces at the near optical axis. The fourth lens L4 has negative refractive power, and the object side surface S7 and the image side surface S8 of the fourth lens L4 are respectively concave and convex surfaces at the near optical axis.

[0105] Specifically, the parameters of the optical lens 100 are given in the following Table 1. Among them, the elements along the optical axis of the optical lens 100 from the object side to the image side are arranged in sequence according to the order of the elements from top to bottom in Table 1. In the same lens, the surface with a smaller surface number is the object side of the lens, and the surface with a larger surface number is the image side of the lens, such as surface numbers 1 and 2 correspond to the object side surface S1 and image side surface S2 of the first lens L1 respectively. The Y radius in Table 1 is the radius of curvature of the object side surface or image side surface of the corresponding surface number at the optical axis. The first value in the "thickness" parameter column of the lens is the thickness of the lens on the optical axis, and the second value is the distance from the image side surface of the lens to the next surface on the optical axis. The value of the aperture STO in the "Thickness" parameter column is the distance from the aperture STO to the vertex of the next surface (the vertex refers to the intersection of the surface and the optical axis) on the optical axis. The default direction from the object side of the first lens L1 to the image side of the last lens is the positive direction of the optical axis. When the value is negative, it indicates that the aperture STO is set on the image side of the next surface vertex. If the aperture STO thickness is a positive value, the aperture STO is on the object side of the next surface vertex. It can be understood that the units of the Y radius, thickness, and focal length in Table 1 are all mm. And the refractive index, Abbe number, etc. in Table 1 are all obtained at a reference wavelength of 587.56nm, and the focal length is obtained at a reference wavelength of 555nm.

[0106] In the first embodiment, the object side surface and the image side surface of any lens of the first lens L1 to the fourth lens L4 are both aspherical surfaces, and the surface shape x of each aspherical lens can be defined by but not limited to the following aspherical surface formula:

[0107]

[0108] Wherein, x is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of h along the optical axis; c is the curvature of the aspheric surface at the optical axis, c=1 / Y (i.e., the paraxial curvature c is the reciprocal of the curvature radius Y in Table 1 below); K is the cone coefficient; Ai is the correction coefficient of the i-th order of the aspheric surface. Table 2 below gives the high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 that can be used for the surface numbers 1-8 in the first embodiment.

[0109] It can be understood that, the surface numbers 1 and 2 in the following Tables 1 and 2 correspond to the object-side surface S1 and the image-side surface S2 of the first lens L1, respectively, the surface numbers 3 and 4 correspond to the object-side surface S3 and the image-side surface S4 of the second lens L2, and so on, the surface numbers 7 and 8 correspond to the object-side surface S7 and the image-side surface S8 of the fourth lens L4, respectively.

[0110] Table 1

[0111]

[0112] Table 2

[0113]

[0114]

[0115] Please refer to (A) in FIG. 2, which shows the longitudinal spherical aberration curve of the optical lens 100 in the first embodiment at wavelengths of 435nm, 470nm, 510nm, 555nm, 610nm and 650nm. In (A) in FIG. 2, the abscissa along the X-axis direction represents the focus offset, and the ordinate along the Y-axis direction represents the normalized field of view. It can be seen from (A) in FIG. 2 that the spherical aberration value of the optical lens 100 in the first embodiment is better, indicating that the imaging quality of the optical lens 100 in this embodiment is better.

[0116] See also Figure 2 (B) in the figure is the astigmatism diagram of the optical lens 100 in the first embodiment at a wavelength of 555 nm. The horizontal axis along the X-axis direction represents the focus offset, and the vertical axis along the Y-axis direction represents the image height, in units of mm. In the astigmatism curve, T represents the curvature of the imaging surface 101 in the meridian direction, and S represents the curvature of the imaging surface 101 in the sagittal direction. Figure 2 It can be seen from (B) in FIG. 1 that at this wavelength, the astigmatism of the optical lens 100 is well compensated.

[0117] See also Figure 2 (C) is a distortion curve of the optical lens 100 in the first embodiment at a wavelength of 555 nm. The horizontal axis along the X-axis represents the distortion, and the vertical axis along the Y-axis represents the image height, in units of mm. Figure 2 As can be seen from (C) in FIG. 1 , at this wavelength, the distortion of the optical lens 100 is well corrected.

[0118] Second embodiment

[0119] like Figure 3 As shown, the optical lens 100 of the present application includes a first lens L1, a filter IR, an aperture STO, a second lens L2, a third lens L3, a fourth lens L4 and a protective glass CG which are arranged in sequence from the object side to the image side along the optical axis.

[0120] In this embodiment, the first lens L1 has negative refractive power, and the object side surface S1 and the image side surface S2 of the first lens L1 are both concave surfaces at the near optical axis. The second lens L2 has positive refractive power, and the object side surface S3 and the image side surface S4 of the second lens L2 are convex and concave surfaces at the near optical axis, respectively. The third lens L3 has positive refractive power, and the object side surface S5 and the image side surface S6 of the third lens L3 are convex and concave surfaces at the near optical axis, respectively. The fourth lens L4 has negative refractive power, and the object side surface S7 and the image side surface S8 of the fourth lens L4 are concave and convex surfaces at the near optical axis, respectively.

[0121] Specifically, the parameters of the optical lens 100 are given in the following Table 3. The definition of each parameter can be obtained from the description of the above-mentioned embodiment, and will not be repeated here. Accordingly, the following Table 4 gives the high-order coefficients of each aspherical lens that can be used in the second embodiment.

[0122] Table 3

[0123]

[0124]

[0125] Table 4

[0126]

[0127] See also Figure 4 It can be seen from the longitudinal spherical aberration curve (A), the light astigmatism diagram (B) and the distortion curve diagram (C) in the figure that the longitudinal spherical aberration, astigmatism and distortion of the optical lens 100 are well controlled, so that the optical lens 100 of this embodiment has good imaging quality. Figure 4 The wavelengths corresponding to the curves (A), (B) and (C) in FIG. 1 can be referred to in the first embodiment. Figure 2 The contents described in (A), (B), and (C) will not be repeated here.

[0128] Third embodiment

[0129] like Figure 5 As shown, the optical lens 100 of the present application includes a first lens L1, a filter IR, an aperture STO, a second lens L2, a third lens L3, a fourth lens L4 and a protective glass CG which are arranged in sequence from the object side to the image side along the optical axis.

[0130] In this embodiment, the first lens L1 has negative refractive power, and the object side surface S1 and the image side surface S2 of the first lens L1 are both concave surfaces at the near optical axis. The second lens L2 has positive refractive power, and the object side surface S3 and the image side surface S4 of the second lens L2 are respectively convex and concave surfaces at the near optical axis. The third lens L3 has positive refractive power, and the object side surface S5 and the image side surface S6 of the third lens L3 are both convex surfaces at the near optical axis. The fourth lens L4 has negative refractive power, and the object side surface S7 and the image side surface S8 of the fourth lens L4 are both concave surfaces at the near optical axis.

[0131] Specifically, the parameters of the optical lens 100 are given in the following Table 5. The definition of each parameter can be obtained from the description of the above-mentioned embodiment, and will not be repeated here. Accordingly, the following Table 6 gives the high-order coefficients of each aspherical lens that can be used in the third embodiment.

[0132] Table 5

[0133]

[0134] Table 6

[0135]

[0136]

[0137] See also Figure 6 It can be seen from the longitudinal spherical aberration curve (A), the light astigmatism diagram (B) and the distortion curve diagram (C) in the figure that the longitudinal spherical aberration, astigmatism and distortion of the optical lens 100 are well controlled, so that the optical lens 100 of this embodiment has good imaging quality. Figure 6 The wavelengths corresponding to the curves (A), (B) and (C) in FIG. 1 can be referred to in the first embodiment. Figure 2 (A) Figure 2 (B) Figure 2 The contents described in (C) will not be repeated here.

[0138] Fourth embodiment

[0139] like Figure 7 As shown, the optical lens 100 of the present application includes a first lens L1, a filter IR, an aperture STO, a second lens L2, a third lens L3, a fourth lens L4 and a protective glass CG which are arranged in sequence from the object side to the image side along the optical axis.

[0140] In this embodiment, the first lens L1 has negative refractive power, and the object side surface S1 and the image side surface S2 of the first lens L1 are both concave surfaces at the near optical axis. The second lens L2 has positive refractive power, and the object side surface S3 and the image side surface S4 of the second lens L2 are respectively convex and concave surfaces at the near optical axis. The third lens L3 has positive refractive power, and the object side surface S5 and the image side surface S6 of the third lens L3 are both convex surfaces at the near optical axis. The fourth lens L4 has negative refractive power, and the object side surface S7 and the image side surface S8 of the fourth lens L4 are both concave surfaces at the near optical axis.

[0141] Specifically, the parameters of the optical lens 100 are given in the following Table 7. The definition of each parameter can be obtained from the description of the above-mentioned embodiment, and will not be repeated here. Accordingly, the following Table 8 gives the high-order coefficients of each aspherical lens that can be used in the fourth embodiment.

[0142] Table 7

[0143]

[0144]

[0145] Table 8

[0146]

[0147] See also Figure 8 It can be seen from the longitudinal spherical aberration curve (A), the light astigmatism diagram (B) and the distortion curve diagram (C) in the figure that the longitudinal spherical aberration, astigmatism and distortion of the optical lens 100 are well controlled, so that the optical lens 100 of this embodiment has good imaging quality. Figure 8 (A) Figure 8 (B) and Figure 8 The wavelengths corresponding to the curves in (C) can be referred to in the first embodiment. Figure 2 (A) Figure 2 (B) Figure 2 The contents described in (C) will not be repeated here.

[0148] Fifth embodiment

[0149] like Fig. 9 As shown, the optical lens 100 of the present application includes a first lens L1, a filter IR, an aperture STO, a second lens L2, a third lens L3, a fourth lens L4 and a protective glass CG which are arranged in sequence from the object side to the image side along the optical axis.

[0150] In this embodiment, the first lens L1 has negative refractive power, and the object side surface S1 and the image side surface S2 of the first lens L1 are convex and concave respectively at the near optical axis. The second lens L2 has positive refractive power, and the object side surface S3 and the image side surface S4 of the second lens L2 are convex and concave respectively at the near optical axis. The third lens L3 has positive refractive power, and the object side surface S5 and the image side surface S6 of the third lens L3 are both convex at the near optical axis. The fourth lens L4 has negative refractive power, and the object side surface S7 and the image side surface S8 of the fourth lens L4 are both concave at the near optical axis.

[0151] Specifically, the parameters of the optical lens 100 are given in the following Table 9, and the definition of each parameter can be obtained from the description of the above-mentioned embodiment, and will not be repeated here. Accordingly, the following Table 10 gives the high-order coefficients of each aspherical lens that can be used in the fifth embodiment.

[0152] Table 9

[0153]

[0154] Table 10

[0155]

[0156] See also Fig.10 ,Depend on Fig.10It can be seen from the longitudinal spherical aberration curve (A), the light astigmatism diagram (B) and the distortion curve diagram (C) in the figure that the longitudinal spherical aberration, astigmatism and distortion of the optical lens 100 are well controlled, so that the optical lens 100 of this embodiment has good imaging quality. Fig.10 (A) Fig.10 (B) and Fig.10 The wavelengths corresponding to the curves in (C) can be referred to in the first embodiment. Figure 2 (A) Figure 2 (B) Figure 2 The contents described in (C) will not be repeated here.

[0157] Please refer to Table 11, which is a summary of the ratios of various relationship equations in the first to fifth embodiments of the present application.

[0158] Table 11

[0159] Relationship / Example First embodiment Second embodiment Third embodiment Fourth embodiment Fifth embodiment f1 / f -0.852 -0.969 -0.894 -1.185 -0.832 f2 / f 1.693 2.523 2.149 1.970 3.043 f3 / f 0.724 0.742 0.768 0.788 0.863 f4 / f -1.117 -1.376 -1.306 -1.347 -1.570 R11 / f -1.200 -1.759 -1.398 -0.753 43.511 R12 / f 0.807 0.789 0.787 4.738 0.442 R21 / f 0.958 1.221 1.103 1.011 1.582 R22 / f -14.815 10.392 21.509 20.598 43.511 R31 / f 0.781 0.765 0.713 0.742 0.852 R32 / f -0.604 -0.645 -0.788 -0.831 -0.742 R41 / f -0.609 -0.674 -0.921 -0.948 -1.101 R42 / f -4.010 -3.074 18.279 19.090 24.266 FOV (unit: degree) 132.100 139.500 130.000 130.000 145.000 TTL / ImgH 2.189 2.000 2.315 1.946 2.422 TTL / f 3.333 4.085 3.833 3.091 4.892 ImgH / f 1.523 2.043 1.655 1.589 2.020 R11 / R12 -1.487 -2.230 -1.776 -0.159 98.443 R22 / R21 -15.461 8.509 19.492 20.384 27.502 R31 / R32 -1.293 -1.186 -0.905 -0.893 -1.147 R42 / R41 6.588 4.563 -19.849 -20.128 -22.034 CT3 / CT4 1.736 1.514 1.340 1.220 1.734 ET1 / CT1 1.409 1.302 1.556 1.311 1.488 ET4 / CT4 1.679 1.717 1.594 1.401 1.728 (|SAG11|+|SAG12|) / CT1 0.717 1.210 1.147 0.620 1.103 (|SAG21|+|SAG22|) / CT2 0.238 0.214 0.287 0.192 0.176 (|SAG31|+|SAG32|) / CT3 0.484 0.732 0.344 0.219 0.455 (|SAG41|+|SAG42|) / CT4 0.814 0.787 0.594 0.401 0.728 f4 / |SAG41| -4.811 -5.121 -8.575 -11.399 -7.739 f4 / |SAG42| -53.456 -110.326 -26.934 -111.422 -16.096 FOV / FNO (unit: deg) 30.023 36.711 34.211 31.707 32.955 TTL / BL 2.420 2.712 2.599 2.620 2.770 TD / ΣAT 2.834 2.889 2.645 3.034 2.893 AT12 / AT34 11.093 12.887 13.463 6.459 21.820 SD11 / SD42 1.046 1.081 1.173 1.113 1.281 SD22 / SD31 0.921 0.921 0.925 0.840 0.889 SD11 / ImgH 0.535 0.467 0.545 0.522 0.545

[0160] See also Fig.11 The present application also discloses a camera module 200, which includes an image sensor 201 and an optical lens 100 as described in any one of the first embodiment to the fifth embodiment of the first aspect above, and the image sensor 201 is arranged on the image side of the optical lens 100. The optical lens 100 is used to receive the light signal of the subject and project it to the image sensor 201, and the image sensor 201 is used to convert the light signal corresponding to the subject into an image signal, which will not be described in detail here. It can be understood that the camera module 200 with the above-mentioned optical lens 100 has all the technical effects of the above-mentioned optical lens 100, and can realize large field of view imaging on the basis of realizing miniaturized design. Since the above-mentioned technical effects have been described in detail in the embodiments of the optical lens 100, they will not be described in detail here.

[0161] See also Fig.12 The present application also discloses an endoscope 300, which includes a tube body 301 and the above-mentioned camera module 200, and the camera module 200 is arranged on the tube body 301. It can be understood that the endoscope 300 may include an industrial endoscope or a medical endoscope.

[0162] The optical lens, camera module and endoscope disclosed in the embodiments of the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the optical lens, camera module and endoscope of the present application and its core ideas. At the same time, for general technicians in this field, according to the ideas of the present application, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. An optical lens, characterized in that: There are a total of four refractive lenses, and the optical lens includes the following components arranged in sequence from the object side to the image side along the optical axis: The first lens, the first lens has a negative refractive power, and the image side surface of the first lens is concave near the optical axis; A filter; The second lens, the second lens has a positive refractive power, and the object side surface of the second lens is convex near the optical axis; The third lens, the third lens has a positive refractive power, and the object side surface of the third lens is convex near the optical axis; The fourth lens, the fourth lens has a negative refractive power, and the object side surface of the fourth lens is concave near the optical axis; The optical lens satisfies the following relational expressions: 110deg < FOV < 155deg and 1.7 < TTL / ImgH < 2.7; Wherein, FOV is the maximum field of view angle of the optical lens, TTL is the distance from the object side surface of the first lens to the imaging surface of the optical lens on the optical axis, and ImgH is half of the image height corresponding to the maximum field of view angle of the optical lens.

2. The optical lens according to claim 1, characterized in that: The optical lens satisfies the following relational expressions: -1.4 < f1 / f < -0.6, and / or, 1.2 < f2 / f < 4, and / or, 0.5 < f3 / f < 1.1, and / or, -2 < f4 / f < -0.8; Wherein, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, and f is the focal length of the optical lens.

3. The optical lens according to claim 1, characterized in that: The optical lens satisfies the following relational expressions: 0.7 < |R11| / f, and / or, 0.3 < R12 / f, and / or, 0.6 < R21 / f < 2, and / or, 9 < |R22| / f, and / or, 0.5 < R31 / f < 1.0, and / or, -1.1 < R32 / f < -0.4, and / or, -1.3 < R41 / f < -0.4, and / or, 3 < |R42| / f, and / or, -1.7 < R31 / R32 < -0.6; Wherein, R11 is the curvature radius of the object side surface of the first lens at the optical axis, R12 is the curvature radius of the image side surface of the first lens at the optical axis, R21 is the curvature radius of the object side surface of the second lens at the optical axis, R22 is the curvature radius of the image side surface of the second lens at the optical axis, R31 is the curvature radius of the object side surface of the third lens at the optical axis, R32 is the curvature radius of the image side surface of the third lens at the optical axis, R41 is the curvature radius of the object side surface of the fourth lens at the optical axis, R42 is the curvature radius of the image side surface of the fourth lens at the optical axis, and f is the focal length of the optical lens.

4. The optical lens according to claim 1, characterized in that: The optical lens satisfies the following relational expressions: 2.5 < TTL / f < 5.5, and / or, 1.2 < ImgH / f < 2.3, and / or, 2.2 < TTL / BL < 3, and / or, 2.5 < TD / ΣAT < 3.5; Wherein, TTL is the distance on the optical axis from the object side surface of the first lens to the imaging surface of the optical lens, TD is the distance on the optical axis from the object side surface of the first lens to the image side surface of the fourth lens, ΣAT is the sum of the distances on the optical axis from the image side surface of the first lens to the object side surface of the filter, from the image side surface of the filter to the object side surface of the second lens, from the image side surface of the second lens to the object side surface of the third lens, and from the image side surface of the third lens to the object side surface of the fourth lens, f is the focal length of the optical lens, and BL is the distance on the optical axis from the image side surface of the fourth lens to the imaging surface of the optical lens.

5. The optical lens according to claim 1, characterized in that: The optical lens satisfies the following relational expressions: 3 < FNO < 5, and / or, 26deg < FOV / FNO < 40deg; Wherein, FNO is the f-number of the optical lens.

6. The optical lens according to claim 1, characterized in that: The optical lens satisfies the following relational expressions: 0.9 < CT3 / CT4 < 2.1, and / or, 1 < ET1 / CT1 < 1.9, and / or, 1 < ET4 / CT4 < 2.1, and / or, 6 < AT12 / AT34 < 22; and / or, 1 < SD11 / SD42 < 1.3, and / or, 0.8 < SD22 / SD31 < 1, and / or, 0.4 < SD11 / ImgH < 0.6; Wherein, CT3 is the thickness of the third lens on the optical axis, CT4 is the thickness of the fourth lens on the optical axis, ET1 is the distance in the direction parallel to the optical axis from the maximum effective semi-aperture at the object side surface of the first lens to the maximum effective semi-aperture at the image side surface of the first lens, ET4 is the distance in the direction parallel to the optical axis from the maximum effective semi-aperture at the object side surface of the fourth lens to the maximum effective semi-aperture at the image side surface of the fourth lens, AT12 is the sum of the distances on the optical axis from the image side surface of the first lens to the object side surface of the filter and from the image side surface of the filter to the object side surface of the second lens, AT34 is the distance on the optical axis from the image side surface of the third lens to the object side surface of the fourth lens, SD11 is the maximum effective semi-aperture of the object side surface of the first lens, SD42 is the maximum effective semi-aperture of the image side surface of the fourth lens, SD22 is the maximum effective semi-aperture of the image side surface of the second lens, and SD31 is the maximum effective semi-aperture of the object side surface of the third lens.

7. The optical lens according to claim 1, characterized in that: The optical lens satisfies the following relational expressions: 0.5 < (|SAG11| + |SAG12|) / CT1 < 1.5, and / or, 0.1 < (|SAG21| + |SAG22|) / CT2 < 0.4, and / or, 0.1 < (|SAG31| + |SAG32|) / CT3 < 0.9, and / or, 0.3 < (|SAG41| + |SAG42|) / CT4 < 1, and / or, -14 < f4 / |SAGY41| < -3, and / or, f4 / |SAGY42| < -10; Wherein, CT1 is the thickness of the first lens on the optical axis, SAG11 is the distance from the maximum effective half-diameter of the object side surface of the first lens to the intersection of the object side surface of the first lens and the optical axis in the direction of the optical axis, SAG12 is the distance from the maximum effective half-diameter of the image side surface of the first lens to the intersection of the image side surface of the first lens and the optical axis in the direction of the optical axis, SAG21 is the distance from the maximum effective half-diameter of the object side surface of the second lens to the intersection of the object side surface of the second lens and the optical axis in the direction of the optical axis, SAG22 is the distance from the maximum effective half-diameter of the image side surface of the second lens to the intersection of the image side surface of the second lens and the optical axis in the direction of the optical axis, and SAG31 is the distance from the object side surface of the third lens SAG32 is the distance from the maximum effective semi-diameter of the image side surface of the third lens to the intersection of the image side surface of the third lens and the optical axis in the optical axis direction, SAG41 is the distance from the maximum effective semi-diameter of the object side surface of the fourth lens to the intersection of the object side surface of the fourth lens and the optical axis in the optical axis direction, SAG42 is the distance from the maximum effective semi-diameter of the image side surface of the fourth lens to the intersection of the image side surface of the fourth lens and the optical axis in the optical axis direction, CT2 is the thickness of the second lens on the optical axis, CT3 is the thickness of the third lens on the optical axis, and CT4 is the thickness of the fourth lens on the optical axis.

8. The optical lens according to claim 1, characterized in that: The optical lens further includes an aperture, which is located between the filter and the object side surface of the second lens, and / or the optical lens further includes a protective glass, which is arranged between the image side surface of the fourth lens and the imaging surface of the optical lens.

9. A camera module, characterized in that: The camera module includes an image sensor and an optical lens as described in any one of claims 1 to 8, and the image sensor is arranged on the image side of the optical lens.

10. An endoscope, characterized in that: The endoscope includes a tube body and a camera module as described in claim 9, and the camera module is arranged on the tube body.

Images