Small-head optical imaging system

Abstract

The invention relates to the technical field of optical lenses, and discloses a small-head optical imaging system, and the optical imaging lens comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are sequentially arranged from the object side to the image side along an optical axis, and the object side surface of the first lens to the image side surface of the fifth lens are aspheric surfaces; the diaphragm is arranged in front of the first lens; the small-head high-definition imaging lens is of a five-lens type, the surface shape structures of all the lenses are combined with the optimal range of optical parameters, the head size of the imaging lens can be effectively shortened and the visual angle of the lens can be improved under the condition that imaging deformation is reduced while imaging is maintained, and the small-head high-definition imaging lens has high resolution brought by high pixels and is high in resolution ratio. The optical imaging lens is small in size and integrated, can adapt to the increasingly pursued light and thin design of a mobile phone, and enables a rear cover of the mobile phone to be flat as far as possible and not to protrude or only to slightly protrude.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical lens, in particular to a small head optical imaging system. BACKGROUND

[0002] With the development of science and technology, people's requirements for lens imaging are getting higher and higher, miniaturization, high performance and high resolution have become the trend of modern electronic products such as mobile phones; with the pixel size of electronic imaging sensor getting smaller and smaller, people's requirements for angle and imaging are also getting higher and higher, and the traditional optical imaging system cannot meet the requirements of higher resolution optical lens system. SUMMARY

[0003] The present application provides a small head optical imaging system, by sequentially arranging first lens, second lens, third lens, fourth lens and fifth lens from object side to image side along the optical axis, and specific design conditions, the problem of high imaging resolution mentioned in the background technology is solved.

[0004] The present application provides the following technical scheme: A small head optical imaging system, the optical imaging lens comprises: first lens, second lens, third lens, fourth lens and fifth lens arranged in sequence from object side to image side along the optical axis, the object side surface of the first lens to the image side surface of the fifth lens are aspherical surface; a diaphragm, arranged before the first lens; the first lens has positive refractive power, and the object side surface thereof is convex at the near axis; the second lens has negative refractive power, and the object side surface thereof is convex; the third lens has positive refractive power, and the image side surface thereof is convex; the fourth lens has positive refractive power, and the object side surface thereof is convex at the near axis, and the image side surface thereof is convex at the near axis; the fifth lens has negative refractive power, and the object side surface thereof is concave at the near axis.

[0005] As a preferred technical scheme of the present application, the optical imaging lens satisfies the following relationship: 4.8450 0.3310

[0006] As a preferred technical scheme of the present application, the optical imaging lens satisfies the following relationship: -1.31

[0007] As a preferred technical scheme of the present application, the optical imaging lens satisfies the following relationship: 0.6130

[0008] As a preferred technical scheme of the present application, the optical imaging lens satisfies the following relationship: 2.05

[0009] As a preferred technical solution of the present application, the optical imaging lens satisfies the following relationship: 1.4340 < TTL / f < 1.498.

[0010] As a preferred technical solution of the present application, the optical imaging lens satisfies the following relationship: 1.5920 < TL / Dg < 1.6100.

[0011] As a preferred technical solution of the present application, the optical imaging lens satisfies the following relationship: -0.792 < F23 / F4 < 0.631.

[0012] As a preferred technical solution of the present application, the optical imaging lens satisfies the following relationship: 10.1970 < f2 / R3 < 10.4120.

[0013] As a preferred technical solution of the present application, the optical imaging lens satisfies the following relationship: 2.4480 < f3 / R5 < 2.4670.

[0014] Compared with the prior art, the present application provides a small-head optical imaging system, which has the following beneficial effects: The parts not involved in the device are the same as or can be realized by the prior art. In the present application, the small-head high-definition imaging lens is a five-lens type, and the combination of the surface structure of each lens and the optimized range of optical parameters can effectively shorten the head size of the imaging lens and improve the lens view angle while reducing the imaging deformation during imaging. The small-volume integrated optical imaging lens technology has high resolution brought by high pixels, can adapt to the increasingly pursued thin design of mobile phones, makes the back cover of the mobile phone as flat as possible, and has only slight bulge, and the multiple lenses are designed in a specific manner, so that the optical imaging lens can meet the requirements of high imaging quality and low distortion. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the specific embodiments or the prior art, the drawings needed in the specific embodiments or the prior art description will be briefly introduced below. In all the drawings, the elements or parts are not necessarily drawn according to the actual proportions.

[0016] Figure 1 is a schematic diagram of the optical imaging lens of the present application; Figure 2 is a schematic diagram of the field curvature / distortion of the present application Figure One ; Figure 3 is a schematic diagram of the axial aberration of the present application Figure One ; Figure 4 is a schematic diagram of the field curvature / distortion of the present application Figure Two ; Figure 5 Axial aberration diagram of the present application Figure Two ; Figure 6 Curvature of field / distortion diagram of the present application Figure Three ; Figure 7 Axial aberration diagram of the present application Figure Three ; Figure 8 Curvature of field / distortion diagram of the present application Figure Four ; Figure 9 Axial aberration diagram of the present application Figure Four .

[0017] In the figure: 1, first lens; 2, second lens; 3, third lens; 4, fourth lens; 5, fifth lens; 6, diaphragm. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0019] Reference Figure 1 , a small head optical imaging system, which is mainly an optical imaging lens, comprising: a first lens 1, a second lens 2, a third lens 3, a fourth lens 4 and a fifth lens 5 arranged in order from the object side to the image side along the optical axis, the object side surface of the first lens 1 to the image side surface of the fifth lens 5 are aspherical surfaces; a diaphragm 6, arranged before the first lens 1; the first lens 1 has positive refractive power, and the object side surface thereof is convex at the near axis; the second lens 2 has negative refractive power, and the object side surface thereof is convex; the third lens 3 has positive refractive power, and the image side surface thereof is convex; the fourth lens 4 has positive refractive power, and the object side surface thereof is convex at the near axis, and the image side surface thereof is convex at the near axis; the fifth lens 5 has negative refractive power, and the object side surface thereof is concave at the near axis.

[0020] In some embodiments, the optical imaging lens satisfies the following relationship: The ratio of the overall focal length value of the optical imaging lens group to the curvature radius of the image side surface of the fourth lens 4 satisfies: 4.8450 < f / R4 < 5.1350; The absolute value range of the ratio of the focal length of the first lens 1 to the focal length of the second lens 2 satisfies: 0.3310 < |f1 / f2| < 0.3340.

[0021] In some embodiments, the ratio of the focal length of the combination of the second lens 2 and the third lens 3 to the focal length of the entire optical imaging lens group satisfies a range of -1.31. <F23 / EFL<-1.25。

[0022] In some embodiments, the ratio of the sum of the center thicknesses of the first lens 1 to the fifth lens 5 on the optical axis to the total optical length of the optical imaging lens satisfies the following range: 0.6130 < ∑CT / TTL < 0.6140.

[0023] In some embodiments, the ratio of the overall focal length of the optical imaging lens group to the entrance pupil diameter of the optical imaging lens satisfies the following range: 2.05 <f / EPD<2.05。

[0024] In some embodiments, the ratio of the total optical length of the optical imaging lens to the overall focal length of the optical imaging lens group satisfies the following range: 1.4340. <TTL / f<1.498。

[0025] In some embodiments, the ratio of the distance between the object-side vertex of the first lens 1 and the imaging plane to the diagonal length of the image plane at the maximum usable viewing angle of the optical imaging lens group satisfies the following range: 1.5920. <TL / Dg<1.6100。

[0026] In some embodiments, the ratio of the focal length of the combination of the second lens 2 and the third lens 3 to the focal length of the fourth lens 4 satisfies the following range: -0.792. <F23 / f4<0.631。

[0027] In some embodiments, the ratio of the focal length of the second lens 2 to the radius of curvature of the image-side surface of the third lens 3 satisfies the following range: 10.1970. <f2 / R3<10.4120。

[0028] In some embodiments, the ratio of the focal length of the third lens 3 to the radius of curvature of the image-side surface of the fifth lens 5 satisfies the following range: 2.4480. <f3 / R5<2.4670。

[0029] In the above embodiments, the meanings of "alphanumeric" are as follows: f: The overall focal length of the optical imaging lens group; R4: Radius of curvature of the image side of the second lens 2; f1: Focal length of the first lens 1; f2: Focal length of the second lens 2; f3: Focal length of the third lens; f4: Focal length of the fourth lens; f23: The focal length of the combination of the second lens 2 and the third lens 3; EFL: Focal length of the optical imaging lens group; TTL: Total optical length of an optical imaging lens; ∑CT: The sum of the center thicknesses of the first lens 1 to the fifth lens 5 on the optical axis; EPD: entrance pupil diameter of an optical imaging lens; TL: Distance between the object-side vertex of the first lens 1 and the imaging plane; Dg: The diagonal length of the image plane at the maximum usable viewing angle of the optical imaging lens group; R3: Radius of curvature of the side surface of the third lens 3; R4: Radius of curvature of the side surface of the fourth lens; R5: Radius of curvature of the side surface of the fifth lens 5.

[0030] Example 1: Based on the above design, the specific selected parameters for the optical imaging lens are: overall focal length f=2.72, aperture fno=2.09, and field of view FOV=81.22°. The parameters are shown in Table 1-1. Figure 2 Field curvature / distortion diagram and Figure 3 Axial mirror aberration diagram;

[0031] The corresponding aspherical coefficients are shown in Table 1-2:

[0032] Example 2: Based on the above design, the specific selected parameters for the optical imaging lens are: overall focal length f=2.57, aperture fno=2.17, and field of view FOV=79.89°. The parameters are shown in Table 2-1. Figure 4 Field curvature / distortion diagram and Figure 5 Axial mirror aberration diagram;

[0033] The corresponding aspherical coefficients are shown in Table 2-2:

[0034] Example 3: Based on the above design, the specific selected parameters for the optical imaging lens are: overall focal length f=2.60, aperture fno=2.16, and field of view FOV=81.31°. The parameters are shown in Table 3-1. Figure 6 Field curvature / distortion diagram and Figure 7 Axial mirror aberration diagram;

[0035] The corresponding aspherical coefficients are shown in Table 3-2:

[0036] Example 4: Based on the above design, the specific selected parameters for the optical imaging lens are: overall focal length f=2.59, aperture fno=2.16, and field of view FOV=80.62°. These parameters are shown in Table 4-1. Figure 8 Field curvature / distortion diagram and Figure 9 Axial mirror aberration diagram;

[0037] The corresponding aspherical coefficients are shown in Table 4-2:

[0038] In this invention, the small-head high-definition imaging lens is a five-lens type. The surface structure of each lens is combined with the optimal range of optical parameters. It can effectively shorten the head size of the imaging lens and improve its lens angle while maintaining imaging and reducing imaging distortion. It has high resolution brought by high pixel count. It is an optical imaging lens technology with small volume integration. It can adapt to the increasingly thin and light design of mobile phones, so that the back cover of the mobile phone is as flat as possible, with no protrusion or only a slight protrusion.

[0039] Components not described in detail in this article are existing technologies.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A small-head optical imaging system, characterized in that, Optical imaging lenses include: A first lens, a second lens, a third lens, a fourth lens, and a fifth lens are arranged sequentially from the object side to the image side along the optical axis. The object side of the first lens to the image side of the fifth lens are all aspherical surfaces. An aperture is positioned in front of the first lens; The first lens has positive refractive power, and its object-side surface is convex near the axis. The second lens has negative refractive power, and its object-side surface is convex. The third lens has positive refractive power, and its image-side surface is convex. The fourth lens has positive refractive power; its object side is convex near the axis, and its image side is convex near the axis. The fifth lens has negative refractive power, and its object-side surface is concave near the axis.

2. The small-head optical imaging system according to claim 1, characterized in that, Optical imaging lenses satisfy the following relationship: 4.8450 < f / R4 < 5.1350; 0.3310 < |f1 / f2| < 0.3340.

3. The small-head optical imaging system according to claim 1, characterized in that, Optical imaging lenses satisfy the following relationship: -1.31 <F23 / EFL<-1.25。 4. The small-head optical imaging system according to claim 1, characterized in that, The optical imaging lens satisfies the following relationship: 0.6130 < ∑CT / TTL < 0.6140.

5. A small-head optical imaging system according to claim 1, characterized in that, Optical imaging lenses satisfy the following relationship: 2.05 <f / EPD<2.05。 6. The small-head optical imaging system according to claim 1, characterized in that, Optical imaging lenses satisfy the following relationship: 1.4340 <TTL / f<1.498。 7. The small-head optical imaging system according to claim 1, characterized in that, Optical imaging lenses satisfy the following relationship: 1.5920 <TL / Dg<1.6100。 8. A small-head optical imaging system according to claim 1, characterized in that, Optical imaging lenses satisfy the following relationship: -0.792 <F23 / F4<0.631。 9. A small-head optical imaging system according to claim 1, characterized in that, Optical imaging lenses satisfy the following relationship: 10.1970 <f2 / R3<10.4120。 10. A small-head optical imaging system according to claim 1, characterized in that, Optical imaging lenses satisfy the following relationship: 2.4480 <f3 / R5<2.4670。

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