Low-distortion optical system and camera module using the same
Patent Information
- Application Number
- CN202611046567.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-14
- Publication Date
- 2026-09-18
AI Technical Summary
[0002]随着科学技术的进步和社会经济发展，摄像镜头被广泛应用到各种不同领域中，如智能机器人，但摄像镜头或低畸变光学系统往往存在成本高、成像质量差、畸变大、视觉范围窄、体积大等缺点
本发明提供了一种成本低、成像质量好、小体积的低畸变光学系统及其应用的摄像模组，主要由5枚非球面塑胶镜片组合，无玻璃镜片，降低物料与加工成本，正负光焦度交替排布搭配高低阿贝数透镜组合，大幅降低色差和畸变，TTL≤5.5mm，实现镜头小型化适配微型机器人模组，在机器视觉、机器人等领域具有更强的竞争力。
Smart Images
Figure CN122776431A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of optical imaging, and more particularly to a low-distortion optical system and a camera module for its application. Background Technology
[0002] With the advancement of science and technology and the development of society and the economy, camera lenses are widely used in various fields, such as intelligent robots. However, camera lenses or low-distortion optical systems often have disadvantages such as high cost, poor image quality, large distortion, narrow visual range, and large size. Summary of the Invention
[0003] To overcome the shortcomings of existing optical lenses in terms of cost, image quality, distortion, and size, this application provides a low-distortion optical system and its application camera module that combines low cost, good image quality, and small size, which is more competitive in fields such as machine vision and robotics.
[0004] A low-distortion optical system comprises, along the optical axis from the object plane to the image plane, a first lens, a second lens, a third lens, a fourth lens, and a fifth lens, wherein: The object-side and image-side surfaces of the first lens are both concave, and its optical power is negative. The object-side and image-side surfaces of the second lens are both convex, and its optical power is positive. The object side of the third lens is convex, the image side is concave, and its optical power is negative. The object-side and image-side surfaces of the fourth lens are both convex, and its optical power is positive. The object-side surface of the fifth lens is convex, and the image-side surface is concave; its optical power is negative. Preferably, each lens of this low-distortion optical system satisfies the following condition: -5mm < f1 < -1.50mm; 1mm < f2 < 2.3mm; -4.3mm < f3 < -1.5mm; 1mm < f4 < 2.7mm; -4.1mm < f5 < -2mm; Where f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, and f5 is the focal length of the fifth lens.
[0005] Preferably, the radius of curvature R of the side surface of the second lens satisfies: R < -1mm.
[0006] Preferably, the low-distortion optical system satisfies the following condition: TTL ≤ 5.5mm; Where TTL is the on-axis distance from the object side of the first lens to the imaging plane.
[0007] Preferably, the refractive index Nd1 and Abbe number Vd1 of the first lens material satisfy: 1.53 < Nd1 < 1.83, 50.00 < Vd1 < 65.00, respectively; The refractive index Nd2 and Abbe number Vd2 of the material of the second lens satisfy the following conditions: 1.53 < Nd2 < 1.83, 50.00 < Vd2 < 65.00; The refractive index Nd3 and Abbe number Vd3 of the material of the third lens satisfy the following conditions: 1.61 < Nd3 < 1.7, 19.00 < Vd3 < 27. The refractive index Nd4 and Abbe number Vd4 of the fourth lens material satisfy the following conditions: 1.53 < Nd4 < 1.83, 50.00 < Vd4 < 65.00; The refractive index Nd5 and Abbe number Vd5 of the fifth lens material satisfy the following conditions: 1.61 < Nd5 < 1.7 and 19.00 < Vd5 < 27, respectively.
[0008] Preferably, the first lens is a plastic aspherical lens.
[0009] Preferably, the field of view (FOV) of the low-distortion optical system satisfies: 115° ≤ FOV.
[0010] Preferably, the third lens and the fourth lens are independent of each other, and an air gap is provided between them.
[0011] Preferably, the F-number of the low-distortion optical system satisfies: 1.8 ≤ F-number ≤ 2.1.
[0012] Preferably, the aperture of the low-distortion optical system is located between the first lens and the second lens.
[0013] On the other hand, this application also provides a camera module, which includes at least an optical lens, and the aforementioned low-distortion optical system is installed in the optical lens.
[0014] Compared with the prior art, the beneficial effects of this application are as follows: This invention provides a low-cost, high-quality, and compact low-distortion optical system and its application in camera modules. It mainly consists of five aspherical plastic lenses, eliminating glass lenses and reducing material and processing costs. The alternating arrangement of positive and negative optical powers, combined with high and low Abbe number lenses, significantly reduces chromatic aberration and distortion. With a TTL of ≤5.5mm, it achieves lens miniaturization to adapt to micro-robot modules, giving it a stronger competitive edge in fields such as machine vision and robotics. Attached Figure Description
[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below.
[0016] Figure 1 This is a schematic diagram of the structure of the low-distortion optical system or camera module of Embodiment 1 of this application; Figure 2 This is a graph showing the astigmatism and distortion of the low-distortion optical system or camera module in Embodiment 1 of this application; Figure 3 This is the MTF curve of the low-distortion optical system or camera module of Embodiment 1 of this application; Figure 4 This is a schematic diagram of the structure of the low-distortion optical system or camera module in Embodiment 2 of this application; Figure 5 This is a graph showing the astigmatism and distortion of the low-distortion optical system or camera module in Embodiment 2 of this application; Figure 6 This is the MTF curve of the low-distortion optical system or camera module of Embodiment 2 of this application; Figure 7 This is a schematic diagram of the structure of the low-distortion optical system or camera module of Embodiment 3 of this application; Figure 8 This is a graph showing the astigmatism and distortion of the low-distortion optical system or camera module in Embodiment 3 of this application; Figure 9 This is the MTF curve of the low-distortion optical system or camera module of Embodiment 3 of this application. Detailed Implementation
[0017] like Figure 1-9 As shown, this application provides a low-distortion optical system, which includes, along the optical axis from the object plane to the image plane, a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, an aperture 6, and a chip protective glass 7, wherein: The object-side surface and the image-side surface of the first lens 1 are both concave, and its optical power is negative. The object-side surface and the image-side surface of the second lens 2 are both convex, and its optical power is positive. The object side of the third lens 3 is convex, and the image side is concave; its optical power is negative. The object-side and image-side surfaces of the fourth lens 4 are both convex, and its optical power is positive. The object-side surface of the fifth lens 5 is convex, and the image-side surface is concave; its optical power is negative. This invention provides a low-distortion optical system and its application in a camera module, mainly composed of five lenses. The first lens 1 has concave object-side and image-side surfaces, and its optical power is negative; the second lens 2 has convex object-side and image-side surfaces, and its optical power is positive; the third lens 3 has a convex object-side surface and a concave image-side surface, and its optical power is negative; the fourth lens 4 has a convex object-side and image-side surface, and its optical power is positive; and the fifth lens 5 has a convex object-side surface and a concave image-side surface, and its optical power is negative. The system features a reasonable number of lenses and a simple structure. By rationally allocating the optical power of the lenses, lens aberrations are optimized, improving the imaging quality of the low-distortion optical system. It also combines low cost, high imaging quality, small size, and short overall length, making it more competitive in the fields of machine vision and robotics.
[0018] Furthermore, as a preferred embodiment of the present invention and not a limitation thereof, each lens of the low-distortion optical system satisfies the following condition, wherein f1 is the focal length of the first lens 1, f2 is the focal length of the second lens 2, f3 is the focal length of the third lens 3, f4 is the focal length of the fourth lens 4, and f5 is the focal length of the fifth lens 5: (1) -5mm < f1 < -1.50mm, by constraining the effective focal length of the first lens 1 within a reasonable range, the distortion of the system is controlled, so that the imaging center has a higher angular resolution; (2) 1mm < f2 < 2.3mm. By constraining the effective focal length of the second lens 2 within a reasonable range, the optical system has excellent temperature characteristics, balances the temperature focus drift problem caused by the negative focal length lens, and can also correct distortion. (3) -4.3mm < f3 < -1.5mm, by constraining the effective focal length of the third lens 3 within a reasonable range, the spherical aberration of the system is finely adjusted and controlled, thereby effectively improving the imaging quality of the system; (4) 1mm < f4 < 2.7mm. By reasonably controlling the effective focal length of the fourth lens 4 within a reasonable range, the astigmatism and field curvature of the system are well corrected, and the imaging quality of the system is effectively improved. (5) -4.1mm < f5 < -2mm. By constraining the effective focal length of the fifth lens 5 within a reasonable range, it is beneficial to balance the aberrations introduced by the preceding lens and improve the imaging quality. Preferably, the refractive index Nd1 and Abbe constant Vd1 of the material of the first lens 1 satisfy: 1.53 < Nd1 < 1.83, 50.00 < Vd1 < 65.00 respectively. This design can effectively reduce chromatic aberration, optimize lens aberration, and thus effectively improve the imaging quality of the system. Preferably, the refractive index Nd2 and Abbe number Vd2 of the material of the second lens 2 satisfy: 1.53 < Nd2 < 1.83, 50.00 < Vd2 < 65.00, respectively, which can ensure good optical performance, further guarantee the viewing angle, improve the lens resolution and adjust the lens distortion; Preferably, the refractive index Nd3 and Abbe number Vd3 of the material of the third lens 3 satisfy: 1.61 < Nd3 < 1.7, 19.00 < Vd3 < 27 respectively. This design can effectively reduce chromatic aberration, optimize lens aberration, and thus effectively improve the imaging quality of the system. Preferably, the refractive index Nd4 and Abbe number Vd4 of the material of the fourth lens 4 satisfy: 1.53 < Nd4 < 1.83, 50.00 < Vd4 < 65.00, which can ensure good optical performance, further guarantee the viewing angle, improve the lens resolution and reduce distortion. Preferably, the refractive index Nd5 and Abbe number Vd5 of the material of the fifth lens 5 satisfy: 1.61 < Nd5 < 1.7, 19.00 < Vd5 < 27 respectively. This design can effectively reduce chromatic aberration, optimize lens aberration, and thus effectively improve the imaging quality of the system. Furthermore, as a preferred embodiment of the present invention and not a limitation thereof, the radius of curvature R of the object side of the first lens 1 satisfies: R < -1mm. By controlling the value of R of the object side of the first lens 1, distortion and field curvature can be effectively corrected, thereby improving the imaging quality of the system.
[0019] Furthermore, as a preferred embodiment of the present invention and not a limitation thereof, the total optical length TTL of the low distortion optical system satisfies: TTL ≤ 5.5mm, where TTL is the on-axis distance from the object side of the first lens 1 to the imaging plane. This design allows the entire low distortion optical system to be integrated within a smaller area, which is beneficial to the miniaturization of the low distortion optical system.
[0020] Furthermore, as a preferred embodiment of the present invention and not a limitation thereof, the first lens 1 is an aspherical lens, preferably made of plastic. This design can improve image quality and correct distortion.
[0021] Furthermore, as a preferred embodiment of the present invention and not a limitation thereof, the full field of view (FOV) of this low-distortion optical system satisfies: 115°≤FOV, a design that meets the application requirements of customers.
[0022] Furthermore, as a preferred embodiment of the present invention and not a limitation thereof, the third lens 3 and the fourth lens 4 are independent of each other, and an air gap is provided between them, which can significantly increase the degree of freedom of the system and improve the imaging quality.
[0023] Furthermore, as a preferred embodiment of the present invention and not a limitation thereof, the F-number of the low-distortion optical system satisfies: 1.8 ≤ F-number ≤ 2.1, which can increase the amount of light entering the low-distortion optical system.
[0024] Furthermore, as a preferred embodiment of the present invention and not a limitation thereof, the aperture 6 of the low-distortion optical system is located between the first lens 1 and the second lens 2, and this design effectively improves the aberrations of the system.
[0025] Specifically, this is a preferred embodiment of the invention and not a limitation thereof, such as Figure 1-3 As shown, in this embodiment 1, the focal length of the first lens 1 is f1 = -2.37mm, the focal length of the second lens 2 is f2 = 1.72mm, the focal length of the third lens 3 is f3 = -3.75mm, the focal length of the fourth lens 4 is f4 = 1.61mm, the focal length of the fifth lens 5 is f5 = -3.82mm, and the total optical length TTL is 5.17mm. The surface type, radius of curvature, thickness, and material parameters of each lens are shown in Table 1. Table 1: Basic parameters of the low-distortion optical system in Example 1
[0026] In Table 1 above, along the optical axis from the object plane to the image plane, OBJ is the object plane; S1 and S2 correspond to the two surfaces of the first lens 1; S3 and S4 correspond to the two surfaces of the second lens 2; S5 and S6 correspond to the two surfaces of the third lens 3; S7 and S8 correspond to the two surfaces of the fourth lens 4; S9 and S10 correspond to the two surfaces of the fifth lens 5; STO is the location of the aperture stop 6; S11 and S12 correspond to the two surfaces of the chip protective glass 7; IMA corresponds to the image plane 8.
[0027] Furthermore, in Table 1, the object-side and image-side surfaces of any lens (excluding the chip protective glass) are aspherical. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formulas:
[0028] Where x is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, h is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the vertex of the aspherical surface, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th higher-order term in the aspherical surface shape formula. Table 2 gives the conic coefficients and higher-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, and A26 that can be used for each aspherical surface in Example 1.
[0029] Table 2: Aspherical correlation values of the lens surface in Example 1
[0030]
[0031] Figure 2 The astigmatism and distortion curves of the optical imaging lens of Example 1 are shown. Astigmatism represents the curvature of the meridional image plane and the curvature of the sagittal image plane, and distortion represents the distortion magnitude value corresponding to different image heights. Figure 3 The MTF curve of the optical imaging lens of Example 1 is shown, which represents the MTF values in the meridional and sagittal directions of different fields of view at different spatial frequencies. Figure 2 and Figure 3 It can be seen that the optical imaging system given in Example 1 can achieve good imaging quality and has higher imaging quality.
[0032] Specifically, this is a preferred embodiment of the invention and not a limitation thereof, such as Figure 4-6 As shown, in this embodiment 2, the focal length of the first lens 1 is f1 = -3.18mm, the focal length of the second lens 2 is f2 = 1.51mm, the focal length of the third lens 3 is f3 = -2.53mm, the focal length of the fourth lens 4 is f4 = 1.48mm, the focal length of the fifth lens 5 is f5 = -3.05mm, and the total optical length TTL is 5.17mm. The surface type, radius of curvature, thickness, and material parameters of each lens are shown in Table 3. Table 3: Basic parameters of the low-distortion optical system in Example 2
[0033] In Table 3 above, along the optical axis from the object plane to the image plane, OBJ is the object plane; S1 and S2 correspond to the two surfaces of the first lens 1; S3 and S4 correspond to the two surfaces of the second lens 2; S5 and S6 correspond to the two surfaces of the third lens 3; S7 and S8 correspond to the two surfaces of the fourth lens 4; S9 and S10 correspond to the two surfaces of the fifth lens 5; STO is the location of the aperture stop 6; S11 and S12 correspond to the two surfaces of the chip protective glass 7; IMA corresponds to the image plane 8.
[0034] Furthermore, in Table 3, the object-side and image-side surfaces of any lens (excluding the chip protective glass) are aspherical. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formulas:
[0035] Where x is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, h is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the vertex of the aspherical surface, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th higher-order term in the aspherical surface shape formula. Table 4 gives the conic coefficients and higher-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, and A26 that can be used for each aspherical surface in Example 2.
[0036] Table 4: Aspherical correlation values of the lens surface in Example 2
[0037]
[0038] Figure 5 The astigmatism and distortion curves of the optical imaging lens in Example 2 are shown. Astigmatism represents the curvature of the meridional image plane and the curvature of the sagittal image plane, and distortion represents the magnitude of distortion at different image heights. Figure 6 The MTF curve of the optical imaging lens of Example 2 is shown, which represents the MTF values in the meridional and sagittal directions of different fields of view at different spatial frequencies. Figure 5 and Figure 6 It can be seen that the optical imaging system given in Example 2 can achieve good imaging quality and has higher imaging quality.
[0039] Specifically, this is a preferred embodiment of the invention and not a limitation thereof, such as Figure 7-9 As shown, in this embodiment 3, the focal length of the first lens 1 is f1 = -3.31mm, the focal length of the second lens 2 is f2 = 1.53mm, the focal length of the third lens 3 is f3 = -2.64mm, the focal length of the fourth lens 4 is f4 = 1.51mm, the focal length of the fifth lens 5 is f5 = -3.12mm, and the total optical length TTL is 5.17mm. The surface type, radius of curvature, thickness, and material parameters of each lens are shown in Table 5. Table 5: Basic parameters of the low-distortion optical system in Example 3
[0040] In Table 5 above, along the optical axis from the object plane to the image plane, OBJ is the object plane; S1 and S2 correspond to the two surfaces of the first lens 1; S3 and S4 correspond to the two surfaces of the second lens 2; S5 and S6 correspond to the two surfaces of the third lens 3; S7 and S8 correspond to the two surfaces of the fourth lens 4; S9 and S10 correspond to the two surfaces of the fifth lens 5; STO is the location of the aperture stop 6; S11 and S12 correspond to the two surfaces of the chip protective glass 7; IMA corresponds to the image plane 8.
[0041] Furthermore, in Table 5, the object-side and image-side surfaces of any lens (excluding the chip protective glass) are aspherical. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formulas:
[0042] Where x is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, h is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the vertex of the aspherical surface, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th higher-order term in the aspherical surface shape formula. Table 6 gives the conic coefficients and higher-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, and A26 for each aspherical surface that can be used in Example 3.
[0043] Table 6: Aspherical Correlation Values of Lens Surface in Example 3
[0044]
[0045] Figure 8 The astigmatism and distortion curves of the optical imaging lens in Example 3 are shown. Astigmatism represents the curvature of the meridional image plane and the curvature of the sagittal image plane, and distortion represents the magnitude of distortion at different image heights. Figure 9 The MTF curve of the optical imaging lens of Example 3 is shown, which represents the MTF values in the meridional and sagittal directions of different fields of view at different spatial frequencies. Figure 8 and Figure 9 It can be seen that the optical imaging system given in Example 3 can achieve good imaging quality and has higher imaging quality.
[0046] Furthermore, in Examples 1-3, the basic data is as follows: Table 7: Basic Data for Examples 1-3
[0047] A camera module includes at least an optical lens, in which the aforementioned low-distortion optical system is installed. The optical lens of the present invention is mainly composed of 5 lenses. By rationally allocating the lens power, optimizing lens aberrations, and improving the imaging quality of the low-distortion optical system, it takes into account the characteristics of low cost, good imaging quality, small size and short overall length, and has stronger competitiveness in the fields of machine vision and robotics.
[0048] The above description provides one or more embodiments in conjunction with specific content, and does not imply that the specific implementation of the present invention is limited to these descriptions. Any methods or structures that are similar to or identical to those of the present invention, or any technical deductions or substitutions made based on the concept of the present invention, should be considered within the scope of protection of the present invention.
Claims
1. A low-distortion optical system, comprising, sequentially from the object plane to the image plane along the optical axis, a first lens, a second lens, a third lens, a fourth lens, and a fifth lens, characterized in that: The object-side and image-side surfaces of the first lens are both concave, and its optical power is negative. The object-side and image-side surfaces of the second lens are both convex, and its optical power is positive. The object side of the third lens is convex, the image side is concave, and its optical power is negative. The object-side and image-side surfaces of the fourth lens are both convex, and its optical power is positive. The object-side surface of the fifth lens is convex, and the image-side surface is concave; its optical power is negative. The lenses of this low-distortion optical system satisfy the following conditions: -5mm < f1 < -1.50mm; 1mm < f2 < 2.3mm; -4.3mm < f3 < -1.5mm; 1mm < f4 < 2.7mm; -4.1mm < f5 < -2mm; Where f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, and f5 is the focal length of the fifth lens.
2. The low-distortion optical system according to claim 1, characterized in that: The radius of curvature R of the side surface of the second lens satisfies: R < -1mm.
3. The low-distortion optical system according to claim 1, characterized in that: This low-distortion optical system meets the following condition: TTL ≤ 5.5mm; Where TTL is the on-axis distance from the object side of the first lens to the imaging plane.
4. The low-distortion optical system according to any one of claims 1-3, characterized in that: The refractive index Nd1 and Abbe number Vd1 of the material of the first lens satisfy the following conditions: 1.53 < Nd1 < 1.83, 50.00 < Vd1 < 65.00; The refractive index Nd2 and Abbe number Vd2 of the material of the second lens satisfy the following conditions: 1.53 < Nd2 < 1.83, 50.00 < Vd2 < 65.00; The refractive index Nd3 and Abbe number Vd3 of the material of the third lens satisfy the following conditions: 1.61 < Nd3 < 1.7, 19.00 < Vd3 < 27. The refractive index Nd4 and Abbe number Vd4 of the fourth lens material satisfy the following conditions: 1.53 < Nd4 < 1.83, 50.00 < Vd4 < 65.00; The refractive index Nd5 and Abbe number Vd5 of the fifth lens material satisfy the following conditions: 1.61 < Nd5 < 1.7 and 19.00 < Vd5 < 27, respectively.
5. The low-distortion optical system according to any one of claims 1-3, characterized in that: The first lens is a plastic aspherical lens.
6. The low-distortion optical system according to any one of claims 1-3, characterized in that: The field of view (FOV) of this low-distortion optical system satisfies: 115° ≤ FOV.
7. The low-distortion optical system according to any one of claims 1-3, characterized in that: The third and fourth lenses are independent of each other, with an air gap between them.
8. The low-distortion optical system according to any one of claims 1-3, characterized in that: The F-number of this low-distortion optical system satisfies: 1.8 ≤ F-number ≤ 2.
1.
9. The low-distortion optical system according to any one of claims 1-3, characterized in that: The aperture of this low-distortion optical system is located between the first lens and the second lens.
10. A camera module, comprising at least an optical lens, characterized in that: The optical lens is equipped with the low-distortion optical system according to any one of claims 1-9.