Large-aperture imaging optical system and camera module applying same

Abstract

The invention provides a large aperture imaging optical system and a camera module applying the same, the large aperture imaging optical system is composed of six lenses, the first lens has negative focal power, the image side surface is a concave surface, the second lens has positive focal power, the object side surface is a convex surface, the image side surface is a convex surface, the third lens has focal power, and the fourth lens has focal power. The fifth lens has focal power, the object side surface is a convex surface, the sixth lens has negative focal power, the object side surface is a convex surface, and the image side surface is a concave surface, six aspheric lenses are selected, and the refractive power and the surface type of each lens are reasonably configured, so that the optical lens can have the characteristics of small aperture, ultra thinness, wide angle and large aperture; meanwhile, detail information of an object can be well captured, the detail ability of the optical lens for capturing the shot object is improved, the picture texture of the optical lens is improved, and the resolution ratio and the imaging definition of the optical lens are improved, so that the high-definition imaging requirement of people on the long-focus optical lens is met.

Description

Technical Field

[0001] This application relates to the field of optical imaging, and particularly to a large-aperture imaging optical system and an imaging module using the same. Background Art

[0002] With the continuous development of technology, people have higher and higher requirements for the imaging quality of optical lenses. It is not only required that the imaging system has high definition and wide angle, but also needs to be lightweight. However, when the existing optical lenses achieve high-resolution imaging, they often face problems such as increased volume, low light efficiency utilization, and insufficient dynamic focusing ability, resulting in poor user experience. Therefore, how to achieve high resolution, wide angle, and large aperture while ensuring the thinness and lightness of the optical system has become a key problem to be solved in the industry. Summary of the Invention

[0003] This application aims to provide a large-aperture imaging optical system, which has the characteristics of ultra-wide angle, small overall size, and large aperture. The structure is compact, which is convenient for processing and installation. At the same time, the configuration of the large aperture can increase the light input of the optical system and higher imaging quality.

[0004] A large-aperture imaging optical system is composed of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens in sequence along the optical axis from the object plane to the image plane; The first lens has a negative focal power, and its image side is concave; The second lens has a positive focal power, its object side is convex, and its image side is convex; The third lens has a focal power; The fourth lens has a focal power; The fifth lens has a focal power, and its object side is convex; The sixth lens has a negative focal power, its object side is convex, and its image side is concave.

[0005] For the large-aperture imaging optical system as described above, the imaging optical system satisfies the following relationships: 1.8 < |(f4 - f5) / (f4 + f5)| < 3.4; 1.0 < f345 / f < 2.5; 2.5 < (f23 + f456) / f < 3.8; Wherein, f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, f345 is the effective combined focal length of the third lens, the fourth lens, and the fifth lens, f is the effective focal length of the imaging optical system, f23 is the combined focal length of the second lens and the third lens, f456 is the combined focal length of the fourth lens, the fifth lens, and the sixth lens, and f is the effective focal length of the imaging optical system.

[0006] The large-aperture imaging optical system as described above, the imaging optical system satisfies the following relationship: 18 ° / mm < (ImgH * HFOV) / (Fno * DT11 * TTL) < 27 ° / mm; Wherein, ImgH is half of the diagonal length of the effective pixel area on the imaging surface, HFOV is half of the maximum field of view angle of the imaging optical system, Fno is the F-number of the optical imaging lens, DT11 is the maximum effective radius of the object side surface of the first lens, and TTL is the axial distance from the object side surface of the first lens to the imaging surface.

[0007] The large-aperture imaging optical system as described above, the imaging optical system satisfies the following relationship: 2.8° / mm < HFOV / ImagH < 3.4° / mm; Wherein, HFOV is half of the maximum field of view angle of the imaging optical system, and ImgH is half of the diagonal length of the effective pixel area on the imaging surface.

[0008] The large-aperture imaging optical system as described above, the imaging optical system satisfies the following relationship: 0.9 < f / R11 < 2.5; 1.6 < DT62 / R12 < 3.3; Wherein, f is the effective focal length of the imaging optical system, R11 is the curvature radius of the object side surface of the sixth lens, R12 is the curvature radius of the image side surface of the sixth lens, and DT62 is the maximum effective radius of the image side surface of the sixth lens.

[0009] The large-aperture imaging optical system as described above, the imaging optical system satisfies the following relationship: 5.5 < TTL / (CT1 + CT2 - T12) < 7.9; 2.6 < CT3 / |SAG6| < 6.0; 1.8 < BFL / (T12 + T23) < 4.7; Wherein, TTL is the axial distance from the object side surface of the first lens to the imaging surface, CT1 is the central thickness of the first lens on the optical axis, CT2 is the central thickness of the second lens on the optical axis, T12 is the air gap between the first lens and the second lens on the optical axis, CT3 is the thickness of the third lens on the optical axis, SAG6 is the distance parallel to the optical axis from the maximum effective aperture of the image side surface of the third lens to the intersection of the image side surface of the third lens and the optical axis, BFL is the shortest distance in the optical axis direction from the image side surface of the sixth lens to the imaging surface of the optical system, T12 is the air gap between the first lens and the second lens on the optical axis, and T23 is the air gap between the second lens and the third lens on the optical axis.

[0010] The large-aperture imaging optical system described above satisfies the following relationship: The imaging optical system satisfies the following relationship: 0 < |(SAG1 - SAG3)| / (SAG1 + SAG3) < 1.8; Wherein, SAG1 is the distance parallel to the optical axis from the intersection of the object side of the first lens and the optical axis to the maximum effective light-passing aperture of the object side of the first lens, and SAG3 is the distance parallel to the optical axis from the intersection of the object side of the second lens and the optical axis to the maximum effective light-passing aperture of the object side of the second lens.

[0011] In the large-aperture imaging optical system described above, the first lens, the second lens, the third lens, the fifth lens, and the sixth lens are aspherical lenses, and are all separated by air gaps.

[0012] In the large-aperture imaging optical system described above, the F number of the imaging optical system ≤ 2.2, and the overall length ≤ 5.1 mm.

[0013] In the large-aperture imaging optical system described above, the following relationship is satisfied: The diaphragm is disposed between the first lens and the second lens.

[0014] On the other hand, an embodiment of the present application further provides an imaging module, which at least includes an optical lens, and the above large-aperture imaging optical system is installed in the optical lens.

[0015] Compared with the prior art, the beneficial effects of the present application are as follows: The present invention provides a large-aperture imaging optical system and an imaging module using the same. By selecting 6 plastic aspherical lenses and reasonably configuring the refractive power and surface shape of each lens, the optical lens can have the characteristics of small aperture, ultra-thin, wide-angle, and large aperture. At the same time, it can also better capture the detailed information of the object, improve the ability of the optical lens to capture the details of the photographed object, improve the image quality of the optical lens, improve the resolution and imaging clarity of the optical lens, so as to meet the high-definition imaging requirements of people for telephoto optical lenses. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments.

[0017] Figure 1 is a schematic structural diagram of the imaging optical system according to Embodiment 1 of the present application; Figure 2 is the axial chromatic aberration, astigmatism, and distortion curves of the imaging optical system according to Embodiment 1 of the present application; Figure 3 is a schematic structural diagram of the imaging optical system according to Embodiment 2 of the present application; Figure 4are the axial chromatic aberration, astigmatism and distortion curves of the imaging optical system according to Embodiment 2 of the present application; Figure 5 is a schematic structural diagram of the imaging optical system according to Embodiment 3 of the present application; Figure 6 are the axial chromatic aberration, astigmatism and distortion curves of the imaging optical system according to Embodiment 3 of the present application; Figure 7 is a schematic structural diagram of the imaging optical system according to Embodiment 4 of the present application; Figure 8 are the axial chromatic aberration, astigmatism and distortion curves of the imaging optical system according to Embodiment 4 of the present application. Detailed implementation manners

[0018] As Figure 1-8 shown, a large-aperture imaging optical system includes a first lens, a diaphragm, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and an infrared filter sequentially arranged from the object side. The first lens, the second lens, the third lens, the fifth lens and the sixth lens are aspherical lenses, and are all separated with air intervals; the first lens has a negative optical power, and its image side is concave; the second lens has a positive optical power, its object side is convex, and its image side is convex; the third lens has an optical power; the fourth lens has an optical power; the fifth lens has an optical power, and its object side is convex; the sixth lens has a negative optical power, its object side is convex, and its image side is concave; the F number of the imaging optical system ≤ 2.2, and the overall length ≤ 5.1 mm.

[0019] The imaging optical system of the embodiment of the present invention is composed of 6 lenses. By selecting 6 aspherical lenses and reasonably configuring the refractive power and surface shape of each lens, the optical lens can have the characteristics of small aperture, ultra-thinness, wide angle and large aperture. At the same time, it can also capture object detail information better, improve the ability of the optical lens to capture details of the photographed object, improve the picture quality of the optical lens, improve the resolution and imaging clarity of the optical lens, so as to meet people's high-definition imaging requirements for long-focus optical lenses.

[0020] As a preferred embodiment of the present application, the optical imaging system satisfies the following condition: 18 ° / mm < (ImgH * HFOV) / (Fno * DT11 * TTL) < 27 ° / mm, where ImgH is half of the diagonal length of the effective pixel area on the imaging surface, HFOV is half of the maximum field of view angle of the imaging optical system, FNO is the F-number of the optical imaging lens, DT11 is the maximum effective radius of the object side surface of the first lens, and TTL is the on-axis distance from the object side surface of the first lens to the imaging surface. This relational expression reflects the constraint conditions of the optical lens in terms of small aperture, ultra-thinness, wide angle, and large aperture characteristics, enabling the optical system to have the characteristics of large aperture and miniaturization while meeting the wide-angle requirement. When it is lower than the lower limit of the relational expression, on the basis of ensuring the wide-angle of the optical system, Fno * DT11 * TTL further increases, which is not conducive to the optical lens meeting the characteristics of miniaturization and large aperture; when it exceeds the upper limit of the relational expression, on the basis of ensuring the wide-angle and large aperture of the optical system, the front-end aperture of the optical system is excessively compressed, making it difficult for the imaging system to obtain good imaging resolution.

[0021] As a preferred embodiment of the present application, the optical imaging system satisfies the following condition: 0.9 < f / R11 < 2.5, where f is the effective focal length of the imaging optical system and R11 is the curvature radius of the object side surface of the sixth lens. By limiting the range of the above relational expression, it is beneficial to constrain the bending degree of the object side surface of the sixth lens, allowing more light to enter the optical system. At the same time, it is also beneficial to reasonably distribute the refractive power of the optical system and correct the off-axis aberration of the optical system. When it exceeds the upper limit of the relational expression, the focal length of the optical system is too large, which is not conducive to realizing the miniaturization characteristic, and thus affects the thinness and lightness of the entire optical system; when it is lower than the lower limit of the relational expression, the curvature radius of the object side surface of the sixth lens is too small, and the image side surface of the sixth lens is too curved, which further increases the ghost image risk.

[0022] As a preferred embodiment of the present application, the optical imaging system satisfies the following condition: 1.6 < DT62 / R12 < 3.3, where R12 is the curvature radius of the image side surface of the sixth lens and DT62 is the maximum effective radius of the image side surface of the sixth lens. By limiting the ratio of the maximum effective semi-aperture of the image side surface of the sixth lens to its image side surface curvature radius, it is beneficial to reasonably control the bending degree of the image side surface of the sixth lens and increase the aperture of the sixth lens in the direction perpendicular to the optical axis, thereby improving the relative illumination of imaging; at the same time, it is also beneficial to suppress the aberration of the edge field of view and improve the imaging quality of the system. When it is lower than the lower limit of the above conditional expression, the effective aperture of the image side surface of the sixth lens is too small, resulting in serious deflection of the edge light and increased edge aberration, which is not conducive to improving the imaging quality. When it exceeds the upper limit of the above conditional expression, the surface shape of the image side surface of the sixth lens is too curved, and the degree of light deflection is too large, which also easily leads to increased edge aberration and is not conducive to improving the imaging quality.

[0023] As a preferred embodiment of the present application, the optical imaging system satisfies the following condition: 5.5 < TTL / (CT1 + CT2 - T12) < 7.9, where TTL is the on-axis distance from the object side surface of the first lens to the imaging surface, CT1 is the central thickness of the first lens on the optical axis, CT2 is the central thickness of the second lens on the optical axis, and T12 is the air gap between the first lens and the second lens on the optical axis. By controlling the ratio range of the above relationship, it is possible to avoid the unreasonable thickness of the first lens and the second lens, reduce the thickness tolerance sensitivity of the optical system, and at the same time, it is also beneficial to control the assembly thickness tolerance of the entire optical system, thereby reducing the production cost. Below the lower limit of the relationship, the thickness of the first lens or the second lens increases, and the thickness tolerance sensitivity of the optical system increases, requiring better processability during manufacturing, thereby increasing the production cost; exceeding the upper limit of the relationship, the overall optical length of the optical system increases, which is not conducive to meeting the requirements of lightweight and miniaturization of the optical system.

[0024] As a preferred embodiment of the present application, the optical imaging system satisfies the following condition: 2.6 < CT3 / |SAG6| < 6.0, where CT3 is the thickness of the third lens on the optical axis, and SAG6 is the distance parallel to the optical axis from the maximum effective clear aperture of the image side surface of the third lens to the intersection of the image side surface of the third lens and the optical axis. By limiting the range of the above conditional formula, it is possible to reasonably configure the ratio of the central thickness of the third lens to the sagittal height of the image side surface, which is beneficial to the reasonable deflection of light when passing through the third lens, thereby improving the imaging quality of the system. At the same time, it is also beneficial to increase the aperture of the third lens, so that light can exit from the third lens at a larger angle. Exceeding the upper limit of the above conditional formula, the sagittal height of the image side surface of the third lens is too small, resulting in excessive deflection of marginal light when passing through the third lens, thereby increasing the marginal aberration of the system and being unfavorable for improving the imaging quality. Below the lower limit of the above conditional formula, the central thickness of the third lens is too small, and the ratio of thicknesses at different positions of the third lens changes too much, which is not conducive to the reasonable deflection of light, resulting in a decrease in the MTF value of the system and a decrease in the system resolution.

[0025] As a preferred embodiment of the present application, the optical imaging system satisfies the following condition: 1.8 < |(f4 - f5) / (f4 + f5)| < 3.4, where f4 is the effective focal length of the fourth lens and f5 is the effective focal length of the fifth lens. By reasonably controlling the focal length ratio of the fourth lens and the fifth lens, the optical system can satisfy a large field of view angle range while obtaining high imaging resolution. Exceeding the upper limit of the relationship, the refractive power of the fourth lens and the fifth lens is insufficient, and it is difficult for large-angle light to enter the optical system, which is not conducive to expanding the field of view angle range of the optical system; below the lower limit of the relationship, the refractive power of the fourth lens and the fifth lens is too strong, and strong astigmatism and chromatic aberration are easily generated, which is not conducive to high-resolution imaging characteristics.

[0026] As a preferred embodiment of the present application, the optical imaging system satisfies the following conditions: 1.0 < f345 / f < 2.5, where f345 is the combined focal length of the third, fourth, and fifth lenses, and f is the effective focal length of the imaging optical system. By constraining the ratio of the combined focal length of the third, fourth, and fifth lenses to the effective focal length of the optical lens, the optical power distribution of the third, fourth, and fifth lenses can be made appropriate, enabling the fourth lens to have diverse cooperation. Thus, on the basis of meeting the miniaturization design of the optical lens, the internal aberration of the optical lens can be balanced, which helps to adjust the field curvature and astigmatism at the imaging edge of the optical lens and meet the imaging quality requirements of the optical lens for the surrounding environment.

[0027] As a preferred embodiment of the present application, the optical imaging system satisfies the following conditions: 2.5 < (f23 + f456) / f < 3.8, where f23 is the combined focal length of the second and third lenses, f456 is the combined focal length of the fourth, fifth, and sixth lenses, and f is the effective focal length of the imaging optical system. By making the optical system satisfy the above relationship, it is beneficial to reasonably constrain the ratio of the combined focal lengths of the second, third, fourth, fifth, and sixth lenses to the focal length of the optical system, correct the aberration generated by the lenses before the light passes through the sixth lens, improve the resolution of the optical system. At the same time, it is also beneficial to reduce the exit angle of the light after being refracted by the optical system and enter the photosensitive element on the image side of the camera module at a smaller angle, thereby improving the photosensitive performance of the photosensitive element and the imaging quality of the camera module.

[0028] As a preferred embodiment of the present application, the optical imaging system satisfies the following conditions: 0 < |(SAG1 - SAG3)| / (SAG1 + SAG3) < 1.8, where SAG1 is the distance parallel to the optical axis from the intersection of the optical axis and the object side surface of the first lens at the maximum effective clear aperture of the object side surface of the first lens, and SAG3 is the distance parallel to the optical axis from the intersection of the optical axis and the object side surface of the second lens at the maximum effective clear aperture of the object side surface of the second lens. By restricting the range of the sagittal height ratio of the object side surfaces of the first and second lenses, the shapes of the object side surfaces of the first and second lenses can be constrained to correct the field curvature of the imaging optical lens and reduce the risk of ghost image generation, thereby improving the imaging quality of the optical lens. When the ratio is higher than the upper limit, the sagittal height of the image side surface of the first lens is too large, making the image side surface of the first lens too curved, which is not conducive to the manufacturing, molding, and assembly of the first lens and easily leads to a decline in the imaging quality of the optical lens.

[0029] As a preferred embodiment of the present application, the optical imaging system satisfies the following conditions: 1.8 < BFL / (T12 + T23) < 4.7, where BFL is the shortest distance from the image side of the sixth lens to the imaging surface of the optical system in the optical axis direction (also known as the optical back focal length), T12 is the air gap between the first lens and the second lens on the optical axis, and T23 is the air gap between the second lens and the third lens on the optical axis. When the above condition formula is satisfied, by controlling the above optical back focal length within a reasonable range, the matching degree between the captured image and the image sensor is effectively ensured, and the matching of the optical system and the image sensor is guaranteed; at the same time, by controlling the thickness of the above combined lens on the optical axis, the compactness of the combined lens structure can be effectively improved, the optical total length of the optical system can be reduced, the size of the optical system can be further reduced, and it can better develop in the direction of miniaturization. Moreover, it is beneficial to the forming and assembly of the combined lens, reduces the manufacturing cost of the optical system, and also reduces the eccentricity sensitivity of the optical system, which is beneficial to ensuring the imaging effect of the optical system.

[0030] Embodiment 1 The following refers to Figures 1 to 2 Describe the optical imaging lens according to Embodiment 1 of the present application. Figure 1 Fig. shows a schematic structural diagram of the optical imaging lens according to Embodiment 1 of the present application.

[0031] As Figure 1 shown, the optical imaging lens according to an exemplary embodiment of the present application sequentially includes, along the optical axis from the object side to the image side: a first lens E1, a STO, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, an infrared filter E7, and an imaging surface S15.

[0032] The first lens E1 has a negative optical power, its object side surface S1 is concave, and its image side surface S2 is concave. The second lens E2 has a positive optical power, its object side surface S3 is convex, and its image side surface S4 is convex. The third lens E3 has a negative optical power, its object side surface S5 is concave, and its image side surface S6 is concave. The fourth lens E4 has a positive optical power, its object side surface S7 is convex, and its image side surface S8 is convex. The fifth lens E5 has a negative optical power, its object side surface S9 is convex, and its image side surface S10 is concave. The sixth lens E6 has a negative optical power, its object side surface S11 is convex, and its image side surface S12 is concave. The filter E7 has an object side surface S13 and an image side surface S14. Light from the object sequentially passes through the surfaces S1 to S14 and finally forms an image on the imaging surface S15.

[0033] Table 1 shows the surface types, curvature radii, thicknesses, and materials of the lenses of the optical imaging lens of Embodiment 1, where the units of the curvature radii and thicknesses are both millimeters (mm).

[0034] Table 1

[0035] In Table 1, for any one of the lenses of the first lens E1, the second lens E2, the third lens E3, the fourth lens E4, the fifth lens E5, and the sixth lens E6, both the object side surface and the image side surface are Q-type aspherical surfaces. The surface shapes of the respective aspherical lenses can be defined by, but are not limited to, the following aspherical formula:

[0036] where Z is the distance from a corresponding point on the aspherical surface to the plane tangent to the surface vertex, r is the radial coordinate of the aspherical surface, c is the curvature of the aspherical surface vertex, K is the conic coefficient, Am is the aspherical coefficient, rmax is the maximum value of the radial radius coordinate, and u = r / rmax. Table 2 gives the conic coefficients and the high-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, and A30 for the respective aspherical surfaces that can be used in the first embodiment.

[0037] Table 2

[0038] Embodiment 2 The following refers to Figures 3 to 4 Describe the optical imaging lens according to Embodiment 2 of the present application. Figure 3 Fig. shows a schematic structural diagram of the optical imaging lens according to Embodiment 2 of the present application.

[0039] As Figure 3 shown, the optical imaging lens according to the exemplary embodiment of the present application sequentially includes, along the optical axis from the object side to the image side: a first lens E1, a STO, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, an infrared filter E7, and an imaging surface S15.

[0040] The first lens E1 has a negative optical power. Its object side surface S1 is a convex surface, and its image side surface S2 is a concave surface. The second lens E2 has a positive optical power. Its object side surface S3 is a convex surface, and its image side surface S4 is a convex surface. The third lens E3 has a negative optical power. Its object side surface S5 is a convex surface, and its image side surface S6 is a concave surface. The fourth lens E4 has a positive optical power. Its object side surface S7 is a concave surface, and its image side surface S8 is a convex surface. The fifth lens E5 has a negative optical power. Its object side surface S9 is a convex surface, and its image side surface S10 is a concave surface. The sixth lens E6 has a negative optical power. Its object side surface S11 is a convex surface, and its image side surface S12 is a concave surface. The filter E7 has an object side surface S13 and an image side surface S14. Light from the object sequentially passes through the respective surfaces S1 to S14 and finally forms an image on the imaging surface S15.

[0041] Table 3 shows the surface type, radius of curvature, thickness, and material of each lens of the optical imaging lens of Embodiment 2. Herein, the units of the radius of curvature and the thickness are both millimeters (mm).

[0042] Table 3

[0043] In Table 3, for any one of the first lens E1, the second lens E2, the third lens E3, the fourth lens E4, the fifth lens E5, and the sixth lens E6, both the object side surface and the image side surface of the lens are Q-type aspherical surfaces. The surface profiles of the aspherical lenses can be defined by, but are not limited to, the following aspherical formula:

[0044] wherein, Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the surface vertex, r is the radial coordinate of the aspherical surface, c is the curvature of the aspherical surface vertex, K is the conic coefficient, Am is the aspherical coefficient, rmax is the maximum value of the radial radius coordinate, and u = r / rmax. Table 4 gives the conic coefficients and the high-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, and A30 for each aspherical surface that can be used in the second embodiment.

[0045] Table 4

[0046] Embodiment Three The following refers to Figures 5 to 6 Describe the optical imaging lens according to Embodiment 3 of the present application. Figure 5 Fig. shows a schematic structural diagram of the optical imaging lens according to Embodiment 3 of the present application.

[0047] As Figure 5 shown, the optical imaging lens according to the exemplary embodiment of the present application sequentially includes, along the optical axis from the object side to the image side: a first lens E1, a STO, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, an infrared filter E7, and an imaging surface S15.

[0048] The first lens E1 has a negative optical power, its object side S1 is convex, and its image side S2 is concave. The second lens E2 has a positive optical power, its object side S3 is convex, and its image side S4 is convex. The third lens E3 has a negative optical power, its object side S5 is convex, and its image side S6 is concave. The fourth lens E4 has a positive optical power, its object side S7 is concave, and its image side S8 is convex. The fifth lens E5 has a negative optical power, its object side S9 is convex, and its image side S10 is concave. The sixth lens E6 has a negative optical power, its object side S11 is convex, and its image side S12 is concave. The filter E7 has an object side S13 and an image side S14. The light from the object sequentially passes through the surfaces S1 to S14 and finally forms an image on the imaging surface S15.

[0049] Table 5 shows the surface types, radii of curvature, thicknesses, and materials of the lenses of the optical imaging lens of Embodiment 3, where the units of the radii of curvature and thicknesses are both millimeters (mm).

[0050] Table 5

[0051] In Table 5, for any one of the lenses of the first lens E1, the second lens E2, the third lens E3, the fourth lens E4, the fifth lens E5, and the sixth lens E6, both the object side and the image side are Q-type aspherical surfaces, and the surface shapes of the aspherical lenses can be defined by, but not limited to, the following aspherical formula:

[0052] where Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the surface vertex, r is the radial coordinate of the aspherical surface, c is the curvature of the aspherical surface vertex, K is the conic coefficient, Am is the aspherical coefficient, rmax is the maximum value of the radial radius coordinate, and u = r / rmax. Table 6 gives the conic coefficients and the high-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, and A30 of the aspherical surfaces that can be used in the third embodiment.

[0053] Table 6

[0054] Embodiment Four The following refers to Figures 7 to 8 Describe the optical imaging lens according to Embodiment 4 of the present application. Figure 7 Shows a schematic structural diagram of the optical imaging lens according to Embodiment 4 of the present application.

[0055] As Figure 7As shown, the optical imaging lens according to an exemplary embodiment of the present application sequentially includes, from the object side to the image side along the optical axis: a first lens E1, a STO, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, an infrared filter E7, and an imaging surface S15.

[0056] The first lens E1 has a negative optical power. Its object surface S1 is convex, and its image surface S2 is concave. The second lens E2 has a positive optical power. Its object surface S3 is convex, and its image surface S4 is convex. The third lens E3 has a positive optical power. Its object surface S5 is concave, and its image surface S6 is convex. The fourth lens E4 has a negative optical power. Its object surface S7 is convex, and its image surface S8 is concave. The fifth lens E5 has a positive optical power. Its object surface S9 is convex, and its image surface S10 is convex. The sixth lens E6 has a negative optical power. Its object surface S11 is convex, and its image surface S12 is concave. The filter E7 has an object surface S13 and an image surface S14. Light from the object sequentially passes through the surfaces S1 to S14 and finally forms an image on the imaging surface S15.

[0057] Table 7 shows the surface types, radii of curvature, thicknesses, and materials of the lenses of the optical imaging lens of Example 4, where the units of the radii of curvature and thicknesses are both millimeters (mm).

[0058] Table 7

[0059] In Table 7, for any one of the lenses of the first lens E1, the second lens E2, the third lens E3, the fourth lens E4, the fifth lens E5, and the sixth lens E6, both the object surface and the image surface are Q-type aspherical surfaces. The surface profiles of the aspherical lenses can be defined by, but are not limited to, the following aspherical formula:

[0060] where Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the surface vertex, r is the radial coordinate of the aspherical surface, c is the curvature of the aspherical surface vertex, K is the conic coefficient, Am is the aspherical coefficient, rmax is the maximum value of the radial radius coordinate, and u = r / rmax. Table 8 gives the conic coefficients and the high-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, and A30 for the aspherical surfaces that can be used in Example 4.

[0061] Table 8

[0062] In Examples 1-4, the basic data is as follows: Table 9

[0063] In Examples 1-4, each conditional expression satisfies the conditions in the following table: Table 10

[0064] An imaging module includes at least an optical lens, and the above-mentioned large-aperture imaging optical system is installed in the optical lens. By selecting 6 aspherical lenses and reasonably configuring the refractive power and surface shape of each lens, it has the characteristics of ultra-wide angle, small overall size and large aperture, with a compact structure, which is convenient for processing and installation. At the same time, the configuration of the large aperture can increase the light input of the optical system and higher imaging quality.

[0065] As described above, one or more implementation manners are provided in combination with specific contents, and it is not determined that the specific implementation of the present invention is only limited to these descriptions. Any implementation similar or identical to the method, structure, etc. of the present invention, or any technical deduction or replacement made under the premise of the inventive concept of the present invention, should be regarded as the protection scope of the present invention.

Claims

1. A large aperture imaging optical system, characterized in that: Along the optical axis, from the object plane to the image plane, it is composed of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens in sequence; The first lens has negative optical power, and its image side surface is concave; The second lens has positive refractive power, and its object side surface is convex, and its image side surface is convex; The third lens has an optical power; The fourth lens has optical power; The fifth lens has optical power, and its object side surface is convex; The sixth lens has negative optical power, its object side surface is convex, and its image side surface is concave; The imaging optical system satisfies the following relationship: 1.8 < |(f4-f5) / (f4+f5)| < 3.4; 1.0 < f345 / f < 2.5; 2.5 < (f23+f456) / f < 3.8; Among them, f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, f345 is the effective combined focal length of the third lens, the fourth lens and the fifth lens, f is the effective focal length of the imaging optical system, f23 is the combined focal length of the second lens and the third lens, f456 is the combined focal length of the fourth lens, the fifth lens and the sixth lens, and f is the effective focal length of the imaging optical system.

2. The large aperture imaging optical system according to claim 1, characterized in that: The imaging optical system satisfies the following relationship: 18 ° / mm < (ImgH*HFOV) / (Fno*DT11*TTL) < 27 ° / mm; Among them, ImgH is half of the diagonal length of the effective pixel area on the imaging plane, HFOV is half of the maximum field of view angle of the imaging optical system, Fno is the F number of the optical imaging lens, DT11 is the maximum effective radius of the object side of the first lens, and TTL is the axial distance from the object side of the first lens to the imaging plane.

3. The large aperture imaging optical system according to claim 1, characterized in that: The imaging optical system satisfies the following relationship: 2.8° / mm < HFOV / ImagH < 3.4° / mm; Among them, HFOV is half of the maximum field of view of the imaging optical system, and ImgH is half of the diagonal length of the effective pixel area on the imaging surface.

4. The large aperture imaging optical system according to any one of claims 1 to 3, characterized in that: The imaging optical system satisfies the following relationship: 0.9 < f / R11 < 2.5; 1.6 < DT62 / R12 < 3.3; Wherein, f is the effective focal length of the imaging optical system, R11 is the curvature radius of the object side of the sixth lens, R12 is the curvature radius of the image side of the sixth lens, and DT62 is the maximum effective radius of the image side of the sixth lens.

5. The large aperture imaging optical system according to any one of claims 1 to 3, characterized in that: The imaging optical system satisfies the following relationship: 5.5 < TTL / (CT1+CT2-T12) < 7.9; 2.6 < CT3 / |SAG6| < 6.0; 1.8 < BFL / (T12+ T23) < 4.7; Among them, TTL is the on-axis distance from the object side of the first lens to the imaging plane, CT1 is the center thickness of the first lens on the optical axis, CT2 is the center thickness of the second lens on the optical axis, T12 is the air gap between the first lens and the second lens on the optical axis, CT3 is the thickness of the third lens on the optical axis, SAG6 is the distance from the maximum effective aperture of the image side of the third lens to the intersection of the image side of the third lens and the optical axis parallel to the optical axis, BFL is the shortest distance from the image side of the sixth lens to the imaging plane of the optical system in the optical axis direction, T12 is the air gap between the first lens and the second lens on the optical axis, and T23 is the air gap between the second lens and the third lens on the optical axis.

6. The large aperture imaging optical system according to any one of claims 1 to 3, characterized in that: The imaging optical system satisfies the following relationship: 0 < |(SAG1-SAG3)| / (SAG1+SAG3) < 1.8; Among them, SAG1 is the distance from the maximum effective aperture of the object side of the first lens to the intersection of the object side of the first lens and the optical axis in the direction parallel to the optical axis, and SAG3 is the distance from the maximum effective aperture of the object side of the second lens to the intersection of the object side of the second lens and the optical axis in the direction parallel to the optical axis.

7. The large aperture imaging optical system according to any one of claims 1 to 3, characterized in that: The first lens, the second lens, the third lens, the fifth lens and the sixth lens are aspherical lenses, and are all separated and arranged with air as intervals.

8. The large aperture imaging optical system according to any one of claims 1 to 3, characterized in that: The imaging optical system has an F number of ≤2.2 and an overall length of ≤5.1 mm.

9. The large aperture imaging optical system according to any one of claims 1 to 3, characterized in that: The following relationship is satisfied: the aperture is provided 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 a large aperture imaging optical system as described in any one of claims 1 to 9.

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