Six-piece low-distortion large-target-surface optical lens

Abstract

The invention discloses a six-piece low-distortion large-target-surface optical lens which is sequentially arranged from an object side to an image side along an optical axis as follows: the object side surface of a first lens is a convex surface, the image side surface of the first lens is a concave surface, and the first lens has positive focal power; the object side surface of the second lens is a concave surface, the image side surface of the second lens is a convex surface, and the second lens has positive focal power; the object side surface of the third lens is a concave surface, the image side surface of the third lens is a convex surface, and the third lens has negative focal power; the object side surface of the fourth lens is a concave surface, the image side surface of the fourth lens is a convex surface, and the fourth lens has positive focal power; the object side surface of the fifth lens is a concave surface, the image side surface of the fifth lens is a convex surface, and the fifth lens has positive focal power; the object side surface of the sixth lens is a concave surface, the image side surface is a concave surface, and the sixth lens has negative focal power. According to the six-piece type low-distortion large-target-surface optical lens, through the optimal design of the first lens to the sixth lens in the technical scheme, the full field angle can reach 108 degrees or above, the optical distortion of the optical system is smaller than 0.6%, the TV distortion is lower than 0.1%, and the target surface gt is larger than gt; and the thickness is 12mm.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical imaging technology, and more particularly to a six-piece low-distortion large target optical lens. BACKGROUND

[0002] At present, the lenses with the same parameters have too many lenses and complex structures, and are mostly made of glass and plastic materials, which makes the overall cost of the lenses too high and the total length of the lenses limited. Compared with general lenses, large target lenses often have smaller field angles or larger distortions, and it is difficult to meet the requirements of large field angles, large targets and low distortions at the same time. At the same time, with the continuous development of the market, large target lenses are required to have lower distortion and larger field angle. SUMMARY

[0003] Therefore, in order to adapt to the development of new technologies, a large target wide-angle lens with a six-piece structure and all-plastic material is provided, and specifically, the present application provides a six-piece low-distortion large target optical lens.

[0004] In order to achieve the above purpose, the present application adopts the following technical scheme: A six-piece low-distortion large target optical lens, from the object side to the image side along the optical axis in order including a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens; The object side of the first lens is convex and the image side is concave, and has positive focal power; The object side of the second lens is concave and the image side is convex, and has positive focal power; The object side of the third lens is concave and the image side is convex, and has negative focal power; The object side of the fourth lens is concave and the image side is convex, and has positive focal power; The object side of the fifth lens is concave and the image side is convex, and has positive focal power; The object side of the sixth lens is concave and the image side is concave, and has negative focal power.

[0005] As a further improvement of the above technical scheme: As an optimization scheme of the above technical scheme, the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are all made of plastic material.

[0006] As an optimization scheme of the above technical scheme, the six-piece low-distortion large target optical lens satisfies the following conditional formula: -0.05 < R1+R2 / R3+R4 < 0.2; -0.9 < R5+R6 / R7+R8 < 0.1; 100 < R9+R10 / R11+R12 < 900; wherein R1 is a radius of curvature of an object side surface of the first lens, and R2 is a radius of curvature of an image side surface of the first lens; R3 is a radius of curvature of an object side surface of the second lens, and R4 is a radius of curvature of an image side surface of the second lens; R5 is a radius of curvature of an object side surface of the third lens, and R6 is a radius of curvature of an image side surface of the third lens; R7 is a radius of curvature of an object side surface of the fourth lens, and R8 is a radius of curvature of an image side surface of the fourth lens; R9 is a radius of curvature of an object side surface of the fifth lens, and R10 is a radius of curvature of an image side surface of the fifth lens; R11 is a radius of curvature of an object side surface of the sixth lens, and R12 is a radius of curvature of an image side surface of the sixth lens.

[0007] As an optimization scheme of the above technical solution, the six-piece low-distortion large target surface optical lens satisfies the following conditional expression: 20≤Vd1≤61; 20≤Vd2≤61; 20≤Vd3≤61; 20≤Vd4≤61; 20≤Vd5≤61; 20≤Vd6≤61; wherein Vd1 is the Abbe number of the first lens; Vd2 is the Abbe number of the second lens; Vd3 is the Abbe number of the third lens; Vd4 is the Abbe number of the fourth lens; Vd5 is the Abbe number of the fifth lens; and Vd6 is the Abbe number of the sixth lens.

[0008] As an optimization scheme of the above technical solution, the six-piece low-distortion large target surface optical lens satisfies the following conditional expression: 2.75<IMH / F<3.5; wherein F is the effective focal length of the six-piece low-distortion large target surface optical lens, and IMH is the total image height of the maximum field of view of the six-piece low-distortion large target surface optical lens.

[0009] As an optimization scheme of the above technical solution, the six-piece low-distortion large target surface optical lens satisfies the following conditional expression: 2<FNO / ENPD<3.5, wherein FNO is the aperture of the six-piece low-distortion large target surface optical lens, and ENPD is the entrance pupil diameter of the six-piece low-distortion large target surface optical lens.

[0010] As the optimization scheme of the above technical solution, the six-piece low-distortion large target surface optical lens satisfies the following conditional expression: 0 < TTL / IMH / FOV < 1; Wherein, TTL is the axial distance from the object side of the first lens to the imaging surface; FOV is the maximum field of view angle of the six-piece low-distortion large target surface optical lens; IMH is the total image height of the maximum field of view of the six-piece low-distortion large target surface optical lens.

[0011] As the optimization scheme of the above technical solution, the six-piece low-distortion large target surface optical lens satisfies the following conditional expression: DFOV >= 108°; Wherein, DFOV is the total field of view angle of the six-piece low-distortion large target surface optical lens.

[0012] As the optimization scheme of the above technical solution, the first lens and the second lens are provided with a diaphragm.

[0013] As the optimization scheme of the above technical solution, the sixth lens and the imaging surface are provided with an IR&CG piece.

[0014] Compared with the prior art, the beneficial effects of the present application are: The six-piece low-distortion large target surface optical lens of the present application can make the total field of view angle reach more than 108°, and the optical distortion of the optical system is less than 0.6%, the TV distortion is less than 0.1%, and the target surface is greater than 12mm, through the optimization design of the first lens to the sixth lens in the technical scheme.

[0015] Secondly, the six-piece low-distortion large target surface optical lens of the present application adopts a full plastic design, which can reduce the cost while effectively reducing the weight of the lens BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The lens section and light path diagram of the six-piece low-distortion large target surface optical lens of the present application embodiment 1; Figure 2 The field curvature distortion diagram of the six-piece low-distortion large target surface optical lens of the present application embodiment 1; Figure 3 The TV distortion diagram of the six-piece low-distortion large target surface optical lens of the present application embodiment 1; Figure 4 The lens section and light path diagram of the six-piece low-distortion large target surface optical lens of the present application embodiment 2; Figure 5 The field curvature distortion diagram of the six-piece low-distortion large target surface optical lens of the present application embodiment 2; Figure 6TV distortion diagram of the six-piece low-distortion large-aperture optical lens of embodiment 2 of the present application; Figure 7 Lens section and light path diagram of the six-piece low-distortion large-aperture optical lens of embodiment 3 of the present application; Figure 8 Field curvature distortion diagram of the six-piece low-distortion large-aperture optical lens of embodiment 3 of the present application; Figure 9 TV distortion diagram of the six-piece low-distortion large-aperture optical lens of embodiment 3 of the present application.

[0017] BRIEF DESCRIPTION OF DRAWINGS: 1, first lens; 2, diaphragm; 3, second lens; 4, third lens; 5, fourth lens; 6, fifth lens; 7, sixth lens; 8, IR&CG piece; 9, imaging surface. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments.

[0019] In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more than two; the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail" and the like indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0020] In the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0021] In the professional description of the technical solution, the object side of the lens refers to the side of the lens facing the object, and the image side refers to the side of the lens facing the imaging surface 9. When a tangent plane is made at any point on the surface of the lens, the object side surface is always on the image side of the tangent plane, and the curvature radius is positive, then the object side surface of the lens is convex; otherwise, the object side surface of the lens is concave. When a tangent plane is made at any point on the surface of the lens, the image side surface is always on the object side of the tangent plane, and the curvature radius is negative, then the image side surface of the lens is convex; otherwise, the image side surface of the lens is concave. If a tangent plane is made at any point on the surface of the lens, the object side surface or the image side surface is on the image side of the tangent plane, and on the object side of the tangent plane, then the surface has a reverse point, and the concave-convex judgment of the object side and the image side surface near the optical axis still applies to the above method.

[0022] The six-piece low-distortion large-target optical lens of the technical solution is composed of six lenses, which has simple structure, small volume, low distortion, and can ensure small distortion, large field of view and large target through the mutual combination of different structure lenses and the reasonable allocation of the focal power of each lens.

[0023] From the object side to the image side along the optical axis, it includes a first lens 1 with positive focal power, a second lens 3 with positive focal power, a third lens 4 with negative focal power, a fourth lens 5 with positive focal power, a fifth lens 6 with positive focal power, and a sixth lens 7 with negative focal power. The object side surface of the first lens 1 is convex and the image side surface is concave, the object side surface of the second lens 3 is concave and the image side surface is convex, the object side surface of the third lens 4 is concave and the image side surface is convex, the object side surface of the fourth lens 5 is concave and the image side surface is convex, the object side surface of the fifth lens 6 is concave and the image side surface is convex, and the object side surface of the sixth lens 7 is concave and the image side surface is concave.

[0024] Through the structure design of the first lens 1 to the sixth lens 7, the target surface of the six-piece low-distortion large-target optical lens involved in the embodiment is greater than 12mm, and has low distortion performance. At the same time, the optical system has a large field of view. The six-piece low-distortion large-target optical lens involved in the embodiment adopts a full-plastic design, which can reduce the cost while effectively reducing the weight of the lens.

[0025] The six lenses are all aspheric lenses, which have strong characteristics of aspheric surface type freedom, strong correction ability of light deflection and aberration than spherical surface, and can further improve the resolution and distortion correction of the lens. It is also conducive to correcting the exit angle of the lens light, which can better match the photosensitive element.

[0026] At the same time, each lens should satisfy the following relationship: 20≤Vd1≤61; 20≤Vd2≤61; 20≤Vd3≤61; 20≤Vd4≤61; 20≤Vd5≤61; 20≤Vd6≤61; wherein Vd1 is the Abbe number of the first lens 1; Vd2 is the Abbe number of the second lens 3; Vd3 is the Abbe number of the third lens 4; Vd4 is the Abbe number of the fourth lens 5; Vd5 is the Abbe number of the fifth lens 6; Vd6 is the Abbe number of the sixth lens 7.

[0027] In addition, the six-piece low-distortion large-target optical lens related to the embodiment can also satisfy the following conditional expression.

[0028] 2.75<IMH / F<3.5 wherein F is the effective focal length of the lens, and IMH is the full image height of the maximum field of view of the lens.

[0029] In the six-piece low-distortion large-target optical lens related to the embodiment, when the system focal length is within a certain range, by controlling the full image height of the optical lens within the above range, the optical lens has a larger target.

[0030] In addition, the six-piece low-distortion large-target optical lens related to the embodiment can also satisfy the following conditional expression.

[0031] -0.05<R1+R2 / R3+R4<0.2 -0.9<R5+R6 / R7+R8<0.1 100<R9+R10 / R11+R12<900 wherein R1 is the radius of curvature of the object side of the first lens 1, R2 is the radius of curvature of the image side of the first lens 1, R3 is the radius of curvature of the object side of the second lens 3, R4 is the radius of curvature of the image side of the second lens 3, R5 is the radius of curvature of the object side of the third lens 4, R6 is the radius of curvature of the image side of the third lens 4, R7 is the radius of curvature of the object side of the fourth lens 5, R8 is the radius of curvature of the image side of the fourth lens 5, R9 is the radius of curvature of the object side of the fifth lens 6, R10 is the radius of curvature of the image side of the fifth lens 6, R11 is the radius of curvature of the object side of the sixth lens 7, and R12 is the radius of curvature of the image side of the sixth lens 7.

[0032] In the embodiment, the lens combination structure satisfying the above curvature relationship can reasonably control the shape of each lens of the optical system, which is helpful to realize a larger field of view, In addition, the six-piece low-distortion large-aperture optical lens according to the embodiment can also satisfy the following conditional expression.

[0033] 2<FNO / ENPD<3.5, wherein FNO is the aperture of the six-piece low-distortion large-aperture optical lens, and ENPD is the entrance pupil diameter of the lens. By satisfying the above relationship, the optical system has a larger aperture.

[0034] In the embodiment, the first lens 1 to the sixth lens 7 are all aspherical lenses. Since the aspherical surface has a large degree of freedom, the correction ability of the deflection and aberration of light is obviously stronger than that of a spherical surface, which is beneficial to improve the resolution and correct the distortion of the lens. At the same time, it is also beneficial to correct the exit angle of the lens, and can better match the photosensitive element.

[0035] In addition, the diaphragm 2 is arranged between the first lens 1 and the second lens 3. By arranging in this way, it is beneficial to meet the requirement of smaller distortion, better balance the exit angle of the optical system, and further improve the imaging quality by matching the corresponding image sensor.

[0036] In addition, the IR&CG plate 8 is arranged between the sixth lens 7 and the imaging surface 9.

[0037] Embodiment 1 As shown in the following table, the related design parameters of the embodiment 1 are as follows: Figure 1 In the above table, the units of surface radius and thickness are millimeters; the surface marked with “*” represents an aspherical surface, and the surface type of the aspherical lens satisfies the following relationship: In the formula, the parameter c is the curvature corresponding to the lens radius, y is the radial coordinate, the unit of the radial coordinate is the same as the unit of the lens length, and k is the conic quadratic coefficient; when the k coefficient is less than -1, the surface type curve of the lens is a hyperbola, when the k coefficient is equal to -1, the surface type curve of the lens is a parabola, when the k coefficient is between -1 and 0, the surface type curve of the lens is an ellipse, when the k coefficient is equal to 0, the surface type curve of the lens is a circle, and when the k coefficient is greater than 0, the surface type curve of the lens is a flat ellipse; a4, a6, a8, a10, a12, a14, and a16 are respectively the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, and sixteenth-order radial coordinates corresponding to the surface coefficients. The numerical value of the conic coefficient k is shown in the above table, and the remaining detailed aspherical surface related parameters are shown in the following table: ; ​Figure 2 is the field curvature distortion chart of the six-piece low-distortion large target surface optical lens 1 of the embodiment. Optical distortion refers to the distortion phenomenon caused by the bending, scattering or refraction of light when passing through optical elements such as lenses or lenses. Mainly affects the shape and picture quality of the picture. Figure 2 , the optical distortion is less than 0.5% picture deformation variable is extremely low. Figure 3 is the TV distortion chart of the six-piece low-distortion large target surface optical lens of the embodiment. TV distortion mainly affects the brightness and color of the image. The TV distortion is less than 0.1%, which is invisible to the human eye, and the picture is more real.

[0038] Moreover, by using different dispersion materials in combination, chromatic aberration can be effectively reduced, so that the system meets higher imaging quality, and the use range of the lens is expanded.

[0039] Embodiment 2 As shown in the attached Figure 4 , the lens cross section and light path chart of embodiment 2, the related design parameters of embodiment 2 are shown in the following table; The rest of the detailed aspherical surface related parameters are shown in the following table; ; Figure 5 is the field curvature distortion chart of the six-piece low-distortion large target surface optical lens 1 of the embodiment. Optical distortion refers to the distortion phenomenon caused by the bending, scattering or refraction of light when passing through optical elements such as lenses or lenses. Mainly affects the shape and picture quality of the picture. Figure Five , the optical distortion is less than 0.5% picture deformation variable is extremely low. Figure 6 is the TV distortion chart of the six-piece low-distortion large target surface optical lens of the embodiment. TV distortion mainly affects the brightness and color of the image. The TV distortion is less than 0.1%, which is invisible to the human eye, and the picture is more real.

[0040] Moreover, by using different dispersion materials in combination, chromatic aberration can be effectively reduced, so that the system meets higher imaging quality, and the use range of the lens is expanded.

[0041] Embodiment 3 As shown in the attached Figure 7 , the lens cross section and light path chart of embodiment 3, the related design parameters of embodiment 3 are shown in the following table; The rest of the detailed aspherical surface related parameters are shown in the following table; ; Figure 8 is the field curvature distortion chart of the six-piece low-distortion large target surface optical lens 1 of the embodiment, and the optical distortion refers to the distortion phenomenon caused by the bending, scattering or refraction of light when passing through optical elements such as lenses or lenses. Mainly affects the shape and picture quality of the picture. Figure 8 , the optical distortion is less than 0.5% picture deformation variable is extremely low. Figure 9 is the TV distortion chart of the six-piece low-distortion large target surface optical lens of the embodiment, and the TV distortion mainly affects the brightness and color of the image. The TV distortion is less than 0.1%, which is invisible to the human eye, and the picture is more real.

[0042] And by using different dispersion materials, chromatic aberration can be effectively reduced, the system can meet higher imaging quality, and the use range of the lens is expanded.

[0043] In summary, according to the optimization design of the three embodiments, the full field angle of the optical system reaches more than 108°, the corresponding TV distortion is less than 0.1%, the image distortion is small, and the imaging picture is more real. Because the aspheric surface is used in the system, the system aberration is well corrected, and high-definition imaging can be realized.

[0044] The above is only a preferred specific embodiment of the technical solution, but the protection scope of the technical solution is not limited to this. Any person skilled in the art can make equivalent replacement or change within the technical range disclosed by the technical solution according to the technical solution and the technical solution concept, which should be covered within the protection scope of the technical solution.

Claims

1. A six-piece low-distortion large-aperture optical lens, characterized in that, from the object side to the image side along the optical axis, sequentially comprising a first lens (1), a second lens (3), a third lens (4), a fourth lens (5), a fifth lens (6), and a sixth lens (7); the object side surface of the first lens (1) is convex and the image side surface is concave, having positive refractive power; the object side surface of the second lens (3) is concave and the image side surface is convex, having positive refractive power; the object side surface of the third lens (4) is concave and the image side surface is convex, having negative refractive power; the object side surface of the fourth lens (5) is concave and the image side surface is convex, having positive refractive power; the object side surface of the fifth lens (6) is concave and the image side surface is convex, having positive refractive power; the object side surface of the sixth lens (7) is concave and the image side surface is concave, having negative refractive power.

2. The six-element low-distortion, large-format optical lens of claim 1, wherein, The first lens (1), the second lens (3), the third lens (4), the fourth lens (5), the fifth lens (6), and the sixth lens (7) are all made of plastic.

3. The six-piece low-distortion large-format optical lens of claim 1, wherein, The six-piece low-distortion large-aperture optical lens satisfies the following conditional expressions: -0.05 < R1+R2 / R3+R4 < 0.2; -0.9 < R5+R6 / R7+R8 < 0.1; 100 < R9+R10 / R11+R12 < 900; wherein, R1 is the curvature radius of the object side surface of the first lens (1), and R2 is the curvature radius of the image side surface of the first lens (1); R3 is the curvature radius of the object side surface of the second lens (3), and R4 is the curvature radius of the image side surface of the second lens (3); R5 is the curvature radius of the object side surface of the third lens (4), and R6 is the curvature radius of the image side surface of the third lens (4); R7 is the curvature radius of the object side surface of the fourth lens (5), and R8 is the curvature radius of the image side surface of the fourth lens (5); R9 is the curvature radius of the object side surface of the fifth lens (6), and R10 is the curvature radius of the image side surface of the fifth lens (6); R11 is the curvature radius of the object side surface of the sixth lens (7), and R12 is the curvature radius of the image side surface of the sixth lens (7).

4. The six-piece low-distortion large-format optical lens of claim 1, wherein, The six-piece low-distortion large-aperture optical lens satisfies the following conditional expressions: 20 < Vd1 < 61; 20 < Vd2 < 61; 20 < Vd3 < 61; 20 < Vd4 < 61; 20 < Vd5 < 61; 20 < Vd6 < 61; wherein, Vd1 is the Abbe number of the first lens (1); Vd2 is the Abbe number of the second lens (3); Vd3 is the Abbe number of the third lens (4); Vd4 is the Abbe number of the fourth lens (5); Vd5 is the Abbe number of the fifth lens (6); and Vd6 is the Abbe number of the sixth lens (7).

5. The six-piece low-distortion large-format optical lens of claim 1, wherein, The six-piece low-distortion large-aperture optical lens satisfies the following conditional expressions: 2.75 < IMH / F < 3.5; wherein, F is the effective focal length of the six-piece low-distortion large-aperture optical lens, and IMH is the full image height of the maximum field of view of the six-piece low-distortion large-aperture optical lens.

6. The six-element low distortion large-format optical lens of claim 1, wherein, The six-piece low-distortion large-aperture optical lens satisfies the following conditional expressions: 2 < FNO / ENPD < 3.5, Wherein, FNO is the aperture of the six-piece low-distortion large target surface optical lens, and ENPD is the entrance pupil diameter of the six-piece low-distortion large target surface optical lens.

7. The six-piece low-distortion large-format optical lens of claim 1, wherein, The six-piece low-distortion large target surface optical lens satisfies the following conditional expression: 0 < TTL / IMH / FOV < 1; Wherein, TTL is the on-axis distance from the object side of the first lens (1) to the imaging surface (9); FOV is the maximum field of view angle of the six-piece low-distortion large target surface optical lens; IMH is the total image height of the maximum field of view of the six-piece low-distortion large target surface optical lens.

8. The six-piece low-distortion large-format optical lens of claim 1, wherein, The six-piece low-distortion large target surface optical lens satisfies the following conditional expression: DFOV is the total field of view angle of the six-piece low-distortion large target surface optical lens. The first lens (1) and the second lens (3) are provided with a diaphragm (2) therebetween.

9. The six-piece low-distortion large-format optical lens of claim 1, wherein, The sixth lens (7) and the imaging surface (9) are provided with an IR&CG piece (8) therebetween.

10. The six-piece low-distortion large-format optical lens of claim 1, wherein, ​

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