Optical imaging lens

Abstract

The utility model discloses an optical imaging lens, which relates to the field of optical lenses, and comprises a first lens group, a second lens group and a third lens group, the first lens group comprises a first lens, a second lens and a third lens which are sequentially arranged along an optical axis from an object side to an image side, the object side surface of the first lens is a convex surface, the image side surface of the first lens is a concave surface, and the object side surface of the second lens is a convex surface; the object side surface of the second lens is a convex surface, the image side surface of the second lens is a concave surface, at least one of the object side surface and the image side surface of the second lens is an aspheric surface, and the object side surface and the image side surface of the third lens are convex surfaces; a diaphragm; the second lens group comprises a fourth lens, a fifth lens and a sixth lens which are sequentially arranged in the direction from the object side to the image side along the optical axis, the object side surface and the image side surface of the fourth lens are convex surfaces, at least one of the object side surface and the image side surface of the fourth lens is an aspheric surface, and the object side surface and the image side surface of the sixth lens are convex surfaces, at least one of the object side surface and the image side surface of the sixth lens is an aspheric surface. The optical imaging lens provided by the technical scheme of the utility model can realize the effect of good imaging quality.

Description

Technical Field

[0001] This utility model relates to the field of optical lens technology, and in particular to an optical imaging lens. Background Technology

[0002] As society develops, people's demands for image quality are gradually increasing. However, the distortion caused by image compression and deformation around the image cannot be easily restored by simply relying on software adjustments. Utility Model Content

[0003] The main purpose of this invention is to provide an optical imaging lens that can maintain low distortion at the periphery of the image and keep the image clear at all times.

[0004] To achieve the above objectives, the present invention proposes an optical imaging lens, which, along an optical axis from the object side to the image side, comprises:

[0005] The first lens group includes a first lens with negative refractive power, a second lens with negative refractive power, and a third lens with positive refractive power, and the three lenses are arranged sequentially along the optical axis from the object side to the image side. The object side of the first lens is convex and the image side is concave. The object side of the second lens is convex and the image side is concave. At least one of the object side and the image side of the second lens is aspherical. The object side and the image side of the third lens are both convex.

[0006] Aperture; and

[0007] The second lens group includes a fourth lens with positive refractive power, a fifth lens with negative refractive power, and a sixth lens with positive refractive power, and the three lenses are arranged sequentially along the optical axis from the object side to the image side. The object side and image side of the fourth lens are both convex and at least one is aspherical. The object side of the fifth lens is concave, the image side is convex and at least one is aspherical. The object side and image side of the sixth lens are both convex and at least one is aspherical.

[0008] The focal length of the optical imaging lens is F, and the combined focal length of the first lens group is fg1, satisfying: -0.4 <F / fg1<0。

[0009] In one embodiment, the focal length of the first lens is f1, and satisfies: -0.4 <F / f1<-0.1。

[0010] In one embodiment, the focal length of the second lens is f2, and satisfies: -0.5 <F / f2<-0.2。

[0011] In one embodiment, the focal length of the third lens is f3, and it satisfies: 0.2 < F / f3 < 0.5.

[0012] In one embodiment, the focal length of the fourth lens is f4, and it satisfies: 0.1 < F / f4 < 0.4.

[0013] In one embodiment, the focal length of the fifth lens is f5, and it satisfies: -0.7 < F / f5 < -0.3.

[0014] In one embodiment, the focal length of the sixth lens is f6, and it satisfies: 0.4 < F / f6 < 0.7.

[0015] In one embodiment, both the object side and the image side of the second lens are aspherical surfaces; and / or,

[0016] both the object side and the image side of the fourth lens are aspherical surfaces; and / or,

[0017] both the object side and the image side of the fifth lens are aspherical surfaces; and / or,

[0018] both the object side and the image side of the sixth lens are aspherical surfaces.

[0019] In one embodiment, the aperture number of the optical imaging lens is FNO, and it satisfies: FNO ≤ 3.8; and / or,

[0020] The field angle of the optical imaging lens is FOV, and it satisfies: 134° ≥ FOV ≥ 93°.

[0021] In one embodiment, the optical imaging lens further includes an infrared filter, a protective glass, and an imaging surface, and the three are arranged in sequence along the optical axis from the object side to the image side. Among them, the infrared filter is arranged on the side of the fifth lens away from the fourth lens.

[0022] In the technical solution of the present utility model, by arranging the first lens group, the aperture stop, and the second lens group in sequence along the optical axis from the object side to the image side, where the first lens group includes three lenses and the second lens group includes three lenses. In this way, six lenses are arranged in sequence from the object side to the image side, and the focal length F of the optical imaging lens and the combined focal length fg1 of the first lens group satisfy the relationship of -0.4 < F / fg1 < 0. Using six lenses, the coordination of their refractive indices and glass shapes enables the periphery of the picture to maintain low distortion, keeps the picture always clear, controls the distortion within a certain range, and achieves the effect of good imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the structure of an embodiment of the optical imaging lens provided by this utility model;

[0025] Figure 2 Field curvature diagram of an embodiment of the optical imaging lens provided by this utility model;

[0026] Figure 3 A distortion diagram of an embodiment of the optical imaging lens provided by this utility model;

[0027] Figure 4 This is a schematic diagram of the structure of the second embodiment of the optical imaging lens provided by this utility model;

[0028] Figure 5 Field curvature diagram of embodiment two of the optical imaging lens provided by this utility model;

[0029] Figure 6 Distortion diagram of the second embodiment of the optical imaging lens provided by this utility model;

[0030] Figure 7 This is a schematic diagram of the structure of the optical imaging lens of embodiment three provided by this utility model;

[0031] Figure 8 Field curvature diagram of embodiment three of the optical imaging lens provided by this utility model;

[0032] Figure 9 The distortion diagram of the optical imaging lens of embodiment three provided by this utility model.

[0033] Explanation of icon numbers:

[0034] 100. First lens group; 110. First lens; 120. Second lens; 130. Third lens;

[0035] 200. Aperture;

[0036] 300. Second lens group; 310. Fourth lens; 320. Fifth lens; 330. Sixth lens;

[0037] 400. Infrared filter;

[0038] 500. Protective glass;

[0039] 600, Imaging plane.

[0040] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0041] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0042] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0043] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0044] In existing technologies, surveillance camera lenses use visible light to capture images during the day and infrared light to assist in nighttime surveillance. In the market, the imaging focus of general lenses will shift due to the use of light sources of different wavelengths, which cannot meet the requirement of maintaining the resolution of megapixels.

[0045] This invention proposes an optical imaging lens.

[0046] Please see Figure 1 , Figure 4 and Figure 7In one embodiment of this utility model, the optical imaging lens includes: a first lens group 100, an aperture 200, and a second lens group 300, which are arranged sequentially along an optical axis O from the object side to the image side. The first lens group 100 includes a first lens 110 with negative refractive power, a second lens 120 with positive refractive power, and a third lens 130 with positive refractive power, arranged sequentially along the optical axis O from the object side to the image side. The first lens 110 has a convex object-side surface S1 and a concave image-side surface S2. The second lens 120 has a convex object-side surface S3 and a concave image-side surface S4. At least one of the object-side surface S3 and the image-side surface S4 of the second lens 120 is aspherical. The third lens has convex object-side surface S5 and the image-side surface S6. The second lens group 300 includes a first lens 110 with negative refractive power, a second lens 120 with positive refractive power, and a third lens 130 with positive refractive power. A fourth lens 310, a fifth lens 320 with negative refractive power, and a sixth lens 330 with positive refractive power are arranged sequentially along the optical axis O from the object side to the image side. The fourth lens 310 has convex object-side surface S7 and image-side surface S8, with at least one being aspherical. The fifth lens 320 has a concave object-side surface S9 and a convex image-side surface S10, with at least one being aspherical. The sixth lens 330 has convex object-side surface S9 and image-side surface S10, with at least one being aspherical. The focal length of the optical forming lens is F, and the combined focal length of the first lens group 100 is fg1, satisfying -0.4. <F / fg1<0。

[0047] Based on the above, in the specific implementation process, the first lens 110, the second lens 120, the third lens 130, the aperture 200, the fourth lens 310, the fifth lens 320 and the sixth lens 330 are installed sequentially along the optical axis O from the object side to the image side, and the five lenses respectively have an object side facing the object side and an image side facing the image side.

[0048] Specifically, the first lens 110 is a convex-concave lens, that is, the object side S1 of the first lens 110 is a convex surface that protrudes towards the object side, the image side S2 is a concave surface, and the optical axis O passes through the object side S1 and the image side S2.

[0049] The second lens 120 is a convex-concave lens, that is, the object-side surface S3 of the second lens 120 is a convex surface protruding towards the object side, and the image-side surface S4 is a concave surface. At least one of the object-side surface S3 and the image-side surface S4 of the second lens 120 is an aspherical surface; the optical axis O passes through the object-side surface S3 and the image-side surface S4.

[0050] The third lens 130 is a biconvex lens, that is, the object side S5 of the third lens 130 is a convex surface convex towards the object side, and the image side S6 is a convex surface convex towards the image side. The optical axis O passes through the object side S5 and the image side S6.

[0051] The aperture stop 200 is disposed between the second lens 120 and the fourth lens 310, and the distances among the three can be adjusted according to requirements.

[0052] The fourth lens 310 is a biconvex lens. That is, the object side surface S7 of the fourth lens 310 is a convex surface protruding toward the object side, the image side surface S8 is a convex surface protruding toward the image side, and at least one of the object side surface S7 and the image side surface S8 is an aspherical surface. The optical axis O passes through the object side surface S7 and the image side surface S8.

[0053] The fifth lens 320 is a concave-convex lens. That is, the object side surface S9 of the fifth lens 320 is a concave surface, the image side surface S10 is a convex surface, and at least one of the object side surface S9 and the image side surface S10 of the fifth lens 320 is an aspherical surface. The optical axis O passes through the object side surface S9 and the image side surface S10.

[0054] The sixth lens 330 is a biconvex lens. That is, the object side surface S11 of the sixth lens 330 is a convex surface protruding toward the object side, the image side surface S12 is a convex surface protruding toward the image side, and at least one of the object side surface S11 and the image side surface S12 of the sixth lens 330 is an aspherical surface. The optical axis O passes through the object side surface S11 and the image side surface S12.

[0055] In the technical solution of the present utility model, the first lens group 100, the aperture stop 200, and the second lens group 300 are sequentially arranged along the optical axis from the object side to the image side. Among them, the first lens group 100 includes three lenses, and the second lens group 300 includes three lenses. In this way, the six lenses are sequentially arranged from the object side to the image side, and the focal length F of the optical imaging lens and the combined focal length fg1 of the first lens group 100 satisfy the relationship of -0.4 < F / fg1 < 0. By using six lenses, the coordination of the refractive index and the glass shape enables the periphery of the picture to maintain low distortion, keeps the picture always clear, controls the distortion within a certain range, and achieves the effect of good imaging quality.

[0056] Further, in order to enable the optical imaging lens to maintain good optical performance and high imaging quality, in the specific implementation process, the optical imaging lens satisfies the following conditions:

[0057] -0.4 < F / f1 < -0.1;

[0058] -0.5 < F / f2 < -0.2;

[0059] 0.2 < F / f3 < 0.5;

[0060] 0.1 < F / f4 < 0.4;

[0061] -0.7 < F / f5 < -0.3;

[0062] 0.4 < F / f6 < 0.7;

[0063] FNO≤3.8;

[0064] 134° ≥ FOV ≥ 93°;

[0065] Where F is the focal length of the optical imaging lens, f1 is the focal length of the first lens 110, f2 is the focal length of the second lens 120, f3 is the focal length of the fourth lens 310, f4 is the focal length of the fifth lens 320, and f5 is the focal length of the sixth lens 330. FNO is the aperture number of the optical imaging lens, and FOV is the field of view of the optical imaging lens.

[0066] In the specific implementation process, the object side S3 and image side S4 of the second lens 120 are both aspherical, the object side S7 and image side S8 of the fourth lens 310 are both aspherical, the object side S9 and image side S10 of the fifth lens 320 are both aspherical, and the object side S11 and image side S12 of the sixth lens 330 are both aspherical.

[0067] In addition, in specific implementation, the optical imaging lens also includes an infrared filter 400, a protective glass 500, and an imaging surface 600, which are arranged sequentially from the object side to the image side along the O-axis. The infrared filter 400 is located on the side of the sixth lens 330 opposite to the fifth lens 320. Specifically, the infrared filter 400 is located between the sixth lens 330 and the protective glass 500 to filter out excess infrared light in the image light, thereby improving image quality. The protective glass 500 is located between the infrared filter 400 and the imaging surface 600 to protect the imaging surface 600, which is used for imaging.

[0068] Example 1

[0069] Based on the above, refer to Figures 1 to 3 As shown, in this embodiment, the aperture stop 200 is located between the second lens 120 and the fourth lens 310. The table below records the system parameters of this embodiment, including the radius of curvature r, center thickness d, refractive index Nd, Abbe constant Vd, and effective aperture D. The unit of distance is mm. Taking the first lens 110 as an example, the numbers 1 and 2 in the table below represent the two surfaces of the first lens 110 in the direction from the object side to the image side, and so on. Numbers 16 and 17 represent the two surfaces of the protective glass 500 in the direction from the object side to the image side.

[0070]

[0071]

[0072] Furthermore, in this embodiment, the aspherical surface profile shape Z of the object-side surface S3 and image-side surface S4 of the second lens 120, the object-side surface S7 and image-side surface S8 of the fourth lens 310, the object-side surface S9 and image-side surface S10 of the fifth lens 320, and the object-side surface S11 and image-side surface S12 of the sixth lens 330 is obtained by the following formula:

[0073]

[0074] in,

[0075] Z: Aspherical surface profile shape;

[0076] c: the reciprocal of the radius of curvature;

[0077] h: Off-axis half-height of the surface;

[0078] k: Conic coefficient;

[0079] A4, A6, A8, A10, A12, A14 and A16: Coefficients of each order of the off-axis half-height h of the surface.

[0080] In this embodiment, the conic coefficient k, radius of curvature R, and coefficients A4, A6, A8, A10, A12, A14, and A16 of the object-side surface S3 and image-side surface S4 of the second lens 120, the object-side surface S7 and image-side surface S8 of the fourth lens 310, the object-side surface S9 and image-side surface S10 of the fifth lens 320, and the object-side surface S11 and image-side surface S12 of the sixth lens 330 are shown in the following table:

[0081]

[0082] The imaging quality of the optical imaging lens is verified using various simulated data from the optical imaging lens in this embodiment, with reference to... Figure 2 For the field curve diagram, Figure 3 This is a distortion image, which can effectively improve image quality.

[0083] Example 2

[0084] Based on the above, refer to Figures 4 to 6 As shown, in this embodiment, the aperture stop 200 is located between and close to the fourth lens 310, and close to the second lens 120. The table below records the system parameters of this embodiment, including the radius of curvature r, center thickness d, refractive index Nd, Abbe constant Vd, and effective aperture D. The unit of distance is mm. Taking the first lens 110 as an example, the numbers 1 and 2 in the table below represent the two surfaces of the first lens 110 in the direction from the object side to the image side, and so on. Numbers 16 and 17 represent the two surfaces of the protective glass 500 in the direction from the object side to the image side.

[0085]

[0086]

[0087] Furthermore, in this embodiment, the aspherical surface profile shape Z of the object-side surface S3 and image-side surface S4 of the second lens 120, the object-side surface S7 and image-side surface S8 of the fourth lens 310, the object-side surface S9 and image-side surface S10 of the fifth lens 320, and the object-side surface S11 and image-side surface S12 of the sixth lens 330 is obtained by the following formula:

[0088]

[0089] in,

[0090] Z: Aspherical surface profile shape;

[0091] c: the reciprocal of the radius of curvature;

[0092] h: Off-axis half-height of the surface;

[0093] k: Conic coefficient;

[0094] A4, A6, A8, A10, A12, A14 and A16: Coefficients of each order of the off-axis half-height h of the surface.

[0095] In this embodiment, the conic coefficient k, radius of curvature R, and coefficients A4, A6, A8, A10, A12, A14, and A16 of the object-side surface S3 and image-side surface S4 of the second lens 120, the object-side surface S7 and image-side surface S8 of the fourth lens 310, the object-side surface S9 and image-side surface S10 of the fifth lens 320, and the object-side surface S11 and image-side surface S12 of the sixth lens 330 are shown in the following table:

[0096]

[0097]

[0098] The imaging quality of the optical imaging lens is verified using various simulated data from the optical imaging lens in this embodiment, with reference to... Figure 5 For the field curve diagram, Figure 6 This is a distortion image, which can effectively improve image quality.

[0099] Example 3

[0100] Based on the above, refer to Figures 7 to 9As shown, in this embodiment, the aperture stop 200 is located between and close to the fourth lens 310, and close to the second lens 120. The table below records the system parameters of this embodiment, including the radius of curvature r, center thickness d, refractive index Nd, Abbe constant Vd, and effective aperture D. The unit of distance is mm. Taking the first lens 110 as an example, the numbers 1 and 2 in the table below represent the two surfaces of the first lens 110 in the direction from the object side to the image side, and so on. Numbers 16 and 17 represent the two surfaces of the protective glass 500 in the direction from the object side to the image side.

[0101]

[0102]

[0103] Furthermore, in this embodiment, the aspherical surface profile shape Z of the object-side surface S3 and image-side surface S4 of the second lens 120, the object-side surface S7 and image-side surface S8 of the fourth lens 310, the object-side surface S9 and image-side surface S10 of the fifth lens 320, and the object-side surface S11 and image-side surface S12 of the sixth lens 330 is obtained by the following formula:

[0104]

[0105] in,

[0106] Z: Aspherical surface profile shape;

[0107] c: the reciprocal of the radius of curvature;

[0108] h: Off-axis half-height of the surface;

[0109] k: Conic coefficient;

[0110] A4, A6, A8, A10, A12, A14 and A16: Coefficients of each order of the off-axis half-height h of the surface.

[0111] In this embodiment, the conic coefficient k, radius of curvature R, and coefficients A4, A6, A8, A10, A12, A14, and A16 of the object-side surface S3 and image-side surface S4 of the second lens 120, the object-side surface S7 and image-side surface S8 of the fourth lens 310, the object-side surface S9 and image-side surface S10 of the fifth lens 320, and the object-side surface S11 and image-side surface S12 of the sixth lens 330 are shown in the following table:

[0112]

[0113]

[0114] The imaging quality of the optical imaging lens is verified using various simulated data from the optical imaging lens in this embodiment, with reference to... Figure 8For the field curve diagram, Figure 9 This is a distortion image, which can effectively improve image quality.

[0115] The above description is merely an exemplary embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural transformations made based on the inventive concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. An optical imaging lens, characterized in that, Along an optical axis from the object side to the image side, the optical imaging lens includes: The first lens group includes a first lens with negative refractive power, a second lens with negative refractive power, and a third lens with positive refractive power, and the three lenses are arranged sequentially along the optical axis from the object side to the image side. The object side of the first lens is convex and the image side is concave. The object side of the second lens is convex and the image side is concave. At least one of the object side and the image side of the second lens is aspherical. The object side and the image side of the third lens are both convex. Aperture; and The second lens group includes a fourth lens with positive refractive power, a fifth lens with negative refractive power, and a sixth lens with positive refractive power, and the three lenses are arranged sequentially along the optical axis from the object side to the image side. The object side and image side of the fourth lens are both convex and at least one is aspherical. The object side of the fifth lens is concave, the image side is convex and at least one is aspherical. The object side and image side of the sixth lens are both convex and at least one is aspherical. The focal length of the optical imaging lens is F, and the combined focal length of the first lens group is fg1, satisfying: -0.4 <F / fg1<0。 2. The optical imaging lens as described in claim 1, characterized in that, The focal length of the first lens is f1, and it satisfies: -0.4 <F / f1<-0.1。 3. The optical imaging lens as described in claim 2, characterized in that, The second lens has a focal length of f2 and satisfies: -0.5 <F / f2<-0.2。 4. The optical imaging lens as described in claim 1, characterized in that, The focal length of the third lens is f3, and it satisfies: 0.2 <F / f3<0.5。 5. The optical imaging lens as described in claim 1, characterized in that, The fourth lens has a focal length of f4 and satisfies: 0.1 <F / f4<0.4。 6. The optical imaging lens as described in claim 1, characterized in that, The fifth lens has a focal length of f5 and satisfies: -0.7 <F / f5<-0.3。 7. The optical imaging lens as described in claim 1, characterized in that, The sixth lens has a focal length of f6 and satisfies: 0.4 <F / f6<0.7。 8. The optical imaging lens as described in claim 1, characterized in that, The object-side and image-side surfaces of the second lens are both aspherical; and / or, The object-side and image-side surfaces of the fourth lens are both aspherical; and / or, The object-side and image-side surfaces of the fifth lens are both aspherical; and / or, The object-side and image-side surfaces of the sixth lens are both aspherical.

9. The optical imaging lens as described in claim 1, characterized in that, The aperture number of the optical imaging lens is FNO, and satisfies: FNO ≤ 3.8; and / or, The field of view of the optical imaging lens is FOV, and satisfies: 134°≥FOV≥93°.

10. The optical imaging lens according to any one of claims 1-9, characterized in that, The optical imaging lens also includes an infrared filter, a protective glass, and an imaging surface, which are arranged sequentially from the object side to the image side along the optical axis. The infrared filter is located on the side of the fifth lens that is away from the fourth lens.

Images