Large-image-plane optical imaging system

Abstract

The invention relates to the technical field of optical lenses, and discloses a large-image-plane optical imaging system which comprises an optical imaging lens comprising 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, and the object side surface of the first lens to the image side surface of the fifth lens are aspheric surfaces. The first lens has negative refractive power, the second lens has positive refractive power, the third lens has positive refractive power, the fourth lens has negative refractive power, the object side surface of the fourth lens is a concave surface in a paraxial position, the image side surface of the fourth lens is a convex surface in a paraxial position, the fifth lens has positive refractive power, and the object side surface of the fifth lens is a convex surface in a paraxial position; the diaphragm is arranged between the first lens and the second lens; according to the invention, through exquisite matching and focal power allocation of the five lenses, while the cost is controlled, the imaging quality comparable to that of six lenses and the optimized diaphragm position and lens shape are realized, so that edge light rays are smoothly incident to a sensor, and the brightness and balance of image edges are ensured.

Description

Technical Field

[0001] This invention relates to the field of optical lens technology, specifically to a large image plane optical imaging system. Background Technology

[0002] With the rapid development of consumer electronics and security monitoring, higher requirements are being placed on lenses, demanding wider angles, higher resolution, less distortion, more compact structures, and lower costs.

[0003] Traditional wide-angle lenses often use a six- or more lens structure. Although they have excellent performance, they have disadvantages such as high cost, complex structure, and large size. Some five-element lenses either have insufficient field of view or have problems such as insufficient edge field of view resolution and severe distortion. Therefore, there is a need for an optical lens that can achieve a large image plane, wide angle, and low distortion with a limited number of lens elements. Summary of the Invention

[0004] This invention provides a large-image-size optical imaging system. Through the ingenious combination of five lenses and the adjustment of optical power, it achieves imaging quality comparable to a six-lens lens while controlling costs. The optimized aperture position and lens shape allow edge light to be smoothly incident on the sensor, ensuring the brightness and uniformity of the image edges. This solves the problems mentioned in the background technology, such as insufficient field of view, insufficient edge field of view resolution, and severe distortion.

[0005] This invention provides the following technical solution: A large-image-plane optical imaging system includes an optical imaging lens comprising: a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially from the object side to the image side. The object side of the first lens to the image side of the fifth lens are all aspherical. The first lens has negative refractive power, and its object side is convex at the paraxial position. The second lens has positive refractive power, and its object side is convex at the paraxial position. The third lens has positive refractive power, and its image side is convex at the paraxial position. The fourth lens has negative refractive power, and its object side is concave at the paraxial position, while its image side is convex at the paraxial position. The fifth lens has positive refractive power, and its object side is convex at the paraxial position. An aperture stop is disposed between the first lens and the second lens.

[0006] As a preferred embodiment of the present invention, the optical imaging lens satisfies the following relationship: -1.65 < f / R4 < -0.35; 0.33 < |f1 / f2| < 1.50.

[0007] As a preferred embodiment of the present invention, 1.12 < (T12 + T23 + T45) / T34 < 3.56.

[0008] As a preferred embodiment of the present invention, 0.23 < ∑CT / TTL < 0.61.

[0009] As a preferred technical solution of the present invention, 3.21 <TTL / EFL<4.15。

[0010] As a preferred embodiment of the present invention, 2.43 <TTL / f<4.49。

[0011] As a preferred embodiment of the present invention, 1.25 <TL / Dg<1.61。

[0012] As a preferred embodiment of the present invention, 40.21 <V3+V5<46.85。

[0013] As a preferred embodiment of the present invention, -0.53 <f2 / R3<-0.12。

[0014] As a preferred embodiment of the present invention, -25.68 <f4 / CT4<-20.36。

[0015] Compared with the prior art, the present invention provides a large image plane optical imaging system, which has the following beneficial effects: The parts not mentioned in this device are the same as or can be implemented using existing technologies. The large image plane optical imaging lens provided by this invention is a five-lens type. The surface structure of each lens is combined with the optimal range of optical parameters. Through the ingenious matching of the five lenses and the adjustment of optical power, while controlling costs, it achieves imaging quality comparable to a six-lens lens. The optimized aperture position and lens shape make the edge light enter the sensor smoothly, ensuring the brightness and uniformity of the image edge. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, the elements or parts are not necessarily drawn to actual scale.

[0017] Figure 1 This is a schematic diagram of the optical imaging lens of the present invention; Figure 2 This is a schematic diagram of the field curvature / distortion of the present invention. Figure 1 ; Figure 3 A schematic diagram of axial aberration of the present invention Figure 1 ; Figure 4 This is a schematic diagram of the field curvature / distortion of the present invention. Figure 2 ; Figure 5 A schematic diagram of axial aberration of the present invention Figure 2 ; Figure 6 This is a schematic diagram of the field curvature / distortion of the present invention. Figure 3 ; Figure 7 A schematic diagram of axial aberration of the present invention Figure 3 ; Figure 8 This is a schematic diagram of the field curvature / distortion of the present invention. Figure 4 ; Figure 9 A schematic diagram of axial aberration of the present invention Figure 4 ; Figure 10 This is a schematic diagram of the field curvature / distortion of the present invention. Figure 5 ; Figure 11 A schematic diagram of axial aberration of the present invention Figure 5 .

[0018] In the diagram: 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Fifth lens; 6. Aperture stop. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Reference Figure 1 A large-image-plane optical imaging system includes 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 sequentially from the object side to the image side. The object side of the first lens 1 to the image side of the fifth lens 5 are all aspherical. Specifically, the first lens 1 has negative refractive power and its object side is convex at the paraxial position; the second lens 2 has positive refractive power and its object side is convex at the paraxial position; the third lens 3 has positive refractive power and its image side is convex at the paraxial position; the fourth lens 4 has negative refractive power, its object side is concave at the paraxial position, and its image side is convex at the paraxial position; and the fifth lens 5 has positive refractive power and its object side is convex at the paraxial position. An aperture 6 is disposed between the first lens 1 and the second lens 2.

[0021] In some embodiments, the optical imaging lens satisfies the following two relationships: The ratio of the overall focal length of the optical imaging lens group to the radius of curvature of the image side of the second lens 2 satisfies the following range: -1.65 < f / R4 < -0.35; 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: 0.33 < |f1 / f2| < 1.50.

[0022] In some embodiments, the ratio of the sum of the optical axis distances from the first lens 1 to the second lens 2, the second lens 2 to the third lens 3, and the fourth lens 4 to the fifth lens 5, to the optical axis distance from the third lens 3 to the fourth lens 4 satisfies the following range: 1.12<(T12+T23+T45) / T34<3.56.

[0023] In some embodiments, the ratio of the sum of the center thicknesses of the first lens 1 to the fifth lens 5 along the optical axis to the total optical length of the optical imaging lens satisfies the following range: 0.23 < ∑CT / TTL < 0.61.

[0024] In some embodiments, the ratio of the total optical length of the optical imaging lens to the focal length of the optical imaging lens satisfies the following range: 3.21 <TTL / EFL<4.15。

[0025] 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 satisfies the following range: 2.43 <TTL / f<4.49。

[0026] 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 satisfies the following range: 1.25 <TL / Dg<1.61。

[0027] In some embodiments, the sum of the Abbe number of the third lens 3 and the Abbe number of the fifth lens 5 satisfies the following range: 40.21 <V3+V5<46.85。

[0028] 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: -0.53 <f2 / R3<-0.12。

[0029] In some embodiments, the ratio of the focal length to the center thickness of the fourth lens 4 satisfies the following range: -25.68 <f4 / CT4<-20.36。

[0030] In the above embodiments, the meanings of "alphanumeric" are as follows: f: Overall focal length of the optical imaging lens; 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; T12: Optical axis distance between the first lens 1 and the second lens 2; T23: The optical axis distance between the second lens 2 and the third lens 3; T34: The optical axis distance between the third lens 3 and the fourth lens 4; T45: The optical axis distance between the fourth lens 4 and the fifth lens 5; 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; TL: Distance between the object-side vertex of the first lens 1 and the imaging plane; Dg: The diagonal length of the image formed on the image plane at the maximum usable angle of view of the optical imaging lens; V3: Abbe number of the third lens 3; V5: Abbe number of the fifth lens 5; R3: Radius of curvature of the side surface of the third lens 3; f4: Focal length of the fourth lens 4; CT4: Center thickness of the fourth lens 4; EFL: Focal length of an optical imaging lens.

[0031] Example 1: Based on the above design, the specific selected parameters for the optical imaging lens are: overall focal length f=2.66, aperture fno=1.41, and field of view FOV=101.44°. The parameters are shown in Table 1-1. Figure 2 and Figure 3 Field curvature / distortion diagram;

[0032] The corresponding aspherical coefficients are shown in Table 2-1:

[0033]

[0034] Example 2: Based on the above design, the specific selected parameters for the optical imaging lens are: overall focal length f=1.74, aperture fno=1.41, and field of view FOV=97.493°. The parameters are shown in Table 2-1. Figure 4 and Figure 5 Field curvature / distortion diagram;

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

[0036]

[0037] Example 3: Based on the above design, the specific selected parameters for the optical imaging lens are: overall focal length f=1.67, aperture fno=1.40, and field of view FOV=99.014°. The parameters are shown in Table 3-1. Figure 6 and Figure 7 Field curvature / distortion diagram;

[0038] The corresponding aspherical coefficients are shown in Table 3-2:

[0039]

[0040] Example 4: Based on the above design, the specific selected parameters for the optical imaging lens are: overall focal length f=1.74, aperture fno=1.41, and field of view FOV=99.446°. These parameters are shown in Table 4-1. Figure 8 and Figure 9 Field curvature / distortion diagram;

[0041] The corresponding aspherical coefficients are shown in Table 4-2:

[0042]

[0043] Example 5: Based on the above design, the specific parameters selected for the optical imaging lens are: overall focal length f=1.60, aperture fno=1.40, and field of view FOV=101.601°. These parameters are shown in Table 5-1. Figure 10 and Figure 11 Field curvature / distortion diagram;

[0044] The corresponding aspherical coefficients are shown in Table 5-2:

[0045]

[0046] The large-image-size optical imaging lens provided by this invention is a five-element lens. The surface structure of each lens is combined with the optimal range of optical parameters. Through the ingenious matching of the five lenses and the adjustment of the optical power, the imaging quality comparable to that of a six-element lens is achieved while controlling costs. The optimized aperture position and lens shape allow the edge light to be smoothly incident on the sensor, ensuring the brightness and uniformity of the image edge.

[0047] Components not described in detail in this article are existing technologies.

[0048] 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 large-image-plane optical imaging system, characterized in that, Optical imaging lenses include: The first lens, second lens, third lens, fourth lens, and fifth lens are arranged sequentially from the object side to the image side. Among them, the object-side surface of the first lens to the image-side surface of the fifth lens are all aspherical. The first lens has negative refractive power and its object-side surface is convex at the paraxial position. The second lens has positive refractive power and its object-side surface is convex at the paraxial position. The third lens has positive refractive power and its image-side surface is convex at the paraxial position. The fourth lens has negative refractive power, its object-side surface is concave at the paraxial position, and its image-side surface is convex at the paraxial position. The fifth lens has positive refractive power and its object-side surface is convex at the paraxial position. An aperture is positioned between the first lens and the second lens.

2. The large image plane optical imaging system according to claim 1, characterized in that, Optical imaging lenses satisfy the following relationship: -1.65 < f / R4 < -0.35; 0.33 < |f1 / f2| < 1.

50.

3. The large image plane optical imaging system according to claim 1, characterized in that, 1.12<(T12+T23+T45) / T34<3.

56.

4. The large image plane optical imaging system according to claim 1, characterized in that, 0.23 < ∑CT / TTL < 0.

61.

5. The large image plane optical imaging system according to claim 1, characterized in that, 3.21 <TTL / EFL<4.15。 6. The large image plane optical imaging system according to claim 1, characterized in that, 2.43 <TTL / f<4.49。 7. The large image plane optical imaging system according to claim 1, characterized in that, 1.25 <TL / Dg<1.61。 8. A large image plane optical imaging system according to claim 1, characterized in that, 40.21 <V3+V5<46.85。 9. A large image plane optical imaging system according to claim 1, characterized in that, -0.53 <f2 / R3<-0.12。 10. A large image plane optical imaging system according to claim 1, characterized in that, -25.68 <f4 / CT4<-20.36。

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