A large-aperture imaging optical system and a camera module using the same

Abstract

The application provides a large-aperture imaging optical system and an application camera module thereof, which are composed of six lenses, the first lens has negative optical power, and the image side is a concave surface; the second lens has positive optical power, the object side is a convex surface, and the image side is a convex surface; the third lens has optical power; the fourth lens has optical power; the fifth lens has optical power, and the object side is a convex surface; and the sixth lens has negative optical power, the object side is a convex surface, and the image side is a concave surface. By selecting six aspheric lenses and reasonably configuring the refractive power and surface type of each lens, the optical lens can have the characteristics of small aperture, ultra-thin, wide angle and large aperture, can also preferably capture the detail information of an object, improve the detail capturing ability of the optical lens for the object, improve the picture quality of the optical lens, and improve the resolution and imaging clarity of the optical lens, so as to meet the high-definition imaging requirement of people on the long-focus optical lens.

Description

Technical Field

[0001] This application relates to the field of optical imaging, and more particularly to a large aperture imaging optical system and a camera module for its application. Background Technology

[0002] With the continuous development of technology, people have increasingly higher requirements for the imaging quality of optical lenses. They not only demand high definition and wide angle from the imaging system, but also need to consider lightweight design. However, while achieving high-resolution imaging, existing optical lenses often face problems such as increased size, low light efficiency, and insufficient dynamic focusing capabilities, resulting in a poor user experience. Therefore, how to achieve high resolution, wide angle, and large aperture while ensuring a thinner and lighter 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 features an ultra-wide angle, small overall size, and large aperture. It has a compact structure, is easy to manufacture and install, and the large aperture configuration can increase the amount of light entering the optical system and achieve higher imaging quality.

[0004] A large aperture imaging optical system, consisting of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens sequentially along the optical axis from the object plane to the image plane;

[0005] The first lens has negative optical power and its image-side surface is concave.

[0006] The second lens has positive optical power, and its object side is convex, as is its image side;

[0007] The third lens has optical power;

[0008] The fourth lens has optical power;

[0009] The fifth lens has optical power and its object side is convex.

[0010] The sixth lens has negative optical power, with its object side being convex and its image side being concave.

[0011] As described above, the large-aperture imaging optical system satisfies the following relationship:

[0012] 1.8 < |(f4-f5) / (f4+f5)| < 3.4;

[0013] 1.0 <f345 / f<2.5;

[0014] 2.5 < (f23 + f456) / f < 3.8;

[0015] 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, fourth and fifth lenses, f is the effective focal length of the imaging optical system, 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.

[0016] As described above, the large-aperture imaging optical system satisfies the following relationship:

[0017] 18 ° / mm<(ImgH*HFOV) / (Fno*DT11*TTL)<27 ° / mm;

[0018] Where ImgH is half the diagonal length of the effective pixel area on the imaging surface, HFOV is half the maximum field of view 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 on-axis distance from the object side of the first lens to the imaging surface.

[0019] As described above, the large-aperture imaging optical system satisfies the following relationship:

[0020] 2.8° / mm <HFOV / ImagH<3.4° / mm;

[0021] Where 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.

[0022] As described above, the large-aperture imaging optical system satisfies the following relationship:

[0023] 0.9 <f / R11<2.5;

[0024] 1.6 <DT62 / R12<3.3;

[0025] Where f is the effective focal length of the imaging optical system, R11 is the radius of curvature of the object side of the sixth lens, R12 is the radius of curvature of the image side of the sixth lens, and DT62 is the maximum effective radius of the image side of the sixth lens.

[0026] As described above, the large-aperture imaging optical system satisfies the following relationship:

[0027] 5.5 <TTL / (CT1+CT2-T12)<7.9;

[0028] 2.6 <CT3 / |SAG6|<6.0;

[0029] 1.8 <BFL / ( T12+ T23)<4.7;

[0030] Wherein, TTL is the axial 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 and second lenses 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 in the direction 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 direction of the optical axis, T12 is the air gap between the first and second lenses on the optical axis, and T23 is the air gap between the second and third lenses on the optical axis.

[0031] The large-aperture imaging optical system described above satisfies the following relationship:

[0032] 0<|(SAG1-SAG3)| / (SAG1+SAG3)<1.8;

[0033] Wherein, SAG1 is the distance from the point where the maximum effective aperture of the first lens surface is parallel to the optical axis to the point where the first lens surface intersects with the optical axis, and SAG3 is the distance from the point where the maximum effective aperture of the second lens surface is parallel to the optical axis to the point where the second lens surface intersects with the optical axis.

[0034] 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 they are all separated by air gaps.

[0035] As described above, the large aperture imaging optical system has an F-number ≤ 2.2 and an overall length ≤ 5.1 mm.

[0036] The large aperture imaging optical system described above satisfies the following relationship: the aperture stop is located between the first lens and the second lens.

[0037] On the other hand, this application embodiment also provides a camera module, which includes at least an optical lens, and the optical lens is equipped with the above-mentioned large aperture imaging optical system.

[0038] Compared with the prior art, the beneficial effects of this application are as follows:

[0039] This invention provides a large-aperture imaging optical system and its application in a camera module. By selecting six plastic aspherical lenses and rationally 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 optical lens's ability to capture the details of the photographed object, improve the image quality of the optical lens, and improve the resolution and image clarity of the optical lens, so as to meet people's requirements for high-definition imaging of telephoto optical lenses. Attached Figure Description

[0040] 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.

[0041] Figure 1 This is a schematic diagram of the imaging optical system of Embodiment 1 of this application;

[0042] Figure 2 These are the on-axis chromatic aberration, astigmatism, and distortion curves of the imaging optical system of Embodiment 1 of this application;

[0043] Figure 3 This is a schematic diagram of the imaging optical system of Embodiment 2 of this application;

[0044] Figure 4 These are the on-axis chromatic aberration, astigmatism, and distortion curves of the imaging optical system of Embodiment 2 of this application;

[0045] Figure 5 This is a schematic diagram of the imaging optical system of Embodiment 3 of this application;

[0046] Figure 6 These are the on-axis chromatic aberration, astigmatism, and distortion curves of the imaging optical system of Embodiment 3 of this application;

[0047] Figure 7 This is a schematic diagram of the imaging optical system of Embodiment 4 of this application;

[0048] Figure 8 These are the on-axis chromatic aberration, astigmatism, and distortion curves of the imaging optical system in Embodiment 4 of this application. Detailed Implementation

[0049] like Figure 1-8As shown, a large-aperture imaging optical system includes a first lens, an aperture stop, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and an infrared filter arranged sequentially from the object side. The first, second, third, fifth, and sixth lenses are aspherical lenses and are separated by air gaps. The first lens has negative optical power and its image-side surface is concave. The second lens has positive optical power and its object-side and image-side surfaces are both convex. The third lens has 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 and its object-side and image-side surfaces are both convex. The imaging optical system has an F-number ≤ 2.2 and an overall length ≤ 5.1 mm.

[0050] The imaging optical system of this invention consists of 6 lenses. By selecting 6 aspherical lenses and rationally 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 optical lens's ability to capture the details of the photographed object, improve the image quality of the optical lens, and improve the resolution and imaging clarity of the optical lens, so as to meet people's requirements for high-definition imaging of telephoto optical lenses.

[0051] In a preferred embodiment of this application, the optical imaging system satisfies the following condition: 18 ° / mm < (ImgH*HFOV) / (Fno*DT11*TTL) < 27 ° / mm, where ImgH is half the diagonal length of the effective pixel area on the imaging plane, HFOV is half the maximum field of view 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. This relationship reflects the constraints of the optical lens in terms of small aperture, ultra-thinness, wide angle, and large aperture characteristics, enabling the optical system to meet the wide-angle requirements while also possessing the characteristics of a large aperture and miniaturization. When the value is below the lower limit of the relationship, Fno*DT11*TTL further increases while ensuring the wide angle of the optical system, which is not conducive to the optical lens meeting the characteristics of miniaturization and a large aperture; when the value exceeds the upper limit of the relationship, the front aperture of the optical system is excessively compressed while ensuring the wide angle and large aperture of the optical system, making it difficult for the imaging system to obtain good imaging resolution.

[0052] As a preferred embodiment of the present application, the optical imaging system satisfies the following conditions: 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 relationship, 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. Exceeding the upper limit of the relationship, the focal length of the optical system is too large, which is not conducive to achieving the miniaturization characteristics and further affects the thinness and lightness of the entire optical system. Below the lower limit of the relationship, 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, thereby increasing the risk of ghost images.

[0053] As a preferred embodiment of the present application, the optical imaging system satisfies the following conditions: 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 curvature radius of the image side surface, 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 illuminance of imaging. At the same time, it is also beneficial to suppress the aberration of the edge field and improve the imaging quality of the system. When below the lower limit of the above conditional formula, the effective aperture of the image side surface of the sixth lens is too small, resulting in serious deflection of the edge light and an increase in edge aberration, which is not conducive to improving the imaging quality. Exceeding the upper limit of the above conditional formula, 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 an increase in edge aberration and is not conducive to improving the imaging quality.

[0054] As a preferred embodiment of the present application, the optical imaging system satisfies the following conditions: 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 unreasonable thicknesses 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 production costs. 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 production costs. 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.

[0055] 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 of the third lens to the intersection of the image side of the third lens and the optical axis. By defining the range of the above conditional formula, the ratio of the central thickness of the third lens to the sagitta of the image side can be reasonably configured, 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 expand the aperture of the third lens, enabling light to exit from the third lens at a larger angle. Exceeding the upper limit of the above conditional formula, the sagitta of the image side 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 various parts of the third lens changes too much, which is unfavorable for the reasonable deflection of light, reducing the MTF value of the system and resulting in a decrease in the system resolution.

[0056] 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 angle range while obtaining high imaging resolution. Exceeding the upper limit of the relational expression, the refractive power of the fourth lens and the fifth lens is insufficient, making it difficult for large-angle light to enter the optical system, which is unfavorable for expanding the field angle range of the optical system; below the lower limit of the relational expression, the refractive power of the fourth lens and the fifth lens is too strong, easily generating strong astigmatism and chromatic aberration, which is unfavorable for high-resolution imaging characteristics.

[0057] As a preferred embodiment of the present application, the optical imaging system satisfies the following condition: 1.0 < f345 / f < 2.5, where f345 is the effective combined focal length of the third lens, the fourth lens, and the fifth lens, and f is the effective focal length of the imaging optical system. By restricting the ratio of the combined focal length of the third lens, the fourth lens, and the fifth lens to the effective focal length of the optical lens, the optical power distribution of the third lens, the fourth lens, and the fifth lens can be made appropriate, enabling the fourth lens to have diverse cooperation. Thus, on the basis of meeting the miniaturized design of the optical lens, the internal aberration of the optical lens can be balanced, and furthermore, it helps to adjust the field curvature and astigmatism of the imaging edge of the optical lens, meeting the imaging quality of the optical lens for the surrounding environment.

[0058] As a preferred embodiment of the present application, the optical imaging system satisfies the following condition: 2.5 < (f23 + f456) / f < 3.8, where 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. By making the optical system satisfy the above relational expression, it is beneficial to reasonably constrain the ratio of the combined focal length of the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens to the focal length of the optical system, correct the aberration generated by the lenses before the light passes through the sixth lens, and 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 located 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.

[0059] As a preferred embodiment of the present application, the optical imaging system satisfies the following condition: 0 < |(SAG1 - SAG3)| / (SAG1 + SAG3) < 1.8, where SAG1 is the distance parallel to the optical axis from the intersection of the object side surface of the first lens and the optical axis to 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 object side surface of the second lens and the optical axis to 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 lens and the second lens, the shapes of the object side surfaces of the first lens and the second lens 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, forming and assembly of the first lens, and easily leads to a decline in the imaging quality of the optical lens.

[0060] As a preferred embodiment of the present application, the optical imaging system satisfies the following condition: 1.8 < BFL / (T12 + T23) < 4.7, where 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 (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 lenses 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 lenses, 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.

[0061] Example 1

[0062] The following is for reference Figures 1 to 2 Describes an optical imaging lens according to Embodiment 1 of this application. Figure 1 A schematic diagram of the structure of an optical imaging lens according to Embodiment 1 of this application is shown.

[0063] like Figure 1 As shown, the optical imaging lens according to an exemplary embodiment of this application includes, in sequence 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.

[0064] The first lens E1 has negative optical power, with its object-side surface S1 being concave and its image-side surface S2 being concave. The second lens E2 has positive optical power, with its object-side surface S3 being convex and its image-side surface S4 being convex. The third lens E3 has negative optical power, with its object-side surface S5 being concave and its image-side surface S6 being concave. The fourth lens E4 has positive optical power, with its object-side surface S7 being convex and its image-side surface S8 being convex. The fifth lens E5 has negative optical power, with its object-side surface S9 being convex and its image-side surface S10 being concave. The sixth lens E6 has negative optical power, with its object-side surface S11 being convex and its image-side surface S12 being concave. The filter E7 has an object-side surface S13 and an image-side surface S14. Light from the object passes sequentially through surfaces S1 to S14 and is finally imaged onto the imaging surface S15.

[0065] Table 1 shows the surface type, radius of curvature, thickness, and material of each lens in the optical imaging lens of Example 1, wherein the units for radius of curvature and thickness are millimeters (mm).

[0066] Table 1

[0067]

[0068] In Table 1, the object-side surface and image-side surface of any one of the lenses E1, E2, E3, E4, E5, and E6 are Q-type aspherical surfaces. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formulas:

[0069]

[0070] Where Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, r is the radial coordinate of the aspherical surface, c is the curvature of the vertex of the aspherical surface, 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 higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28 and A30 of each aspherical surface that can be used in the first embodiment.

[0071] Table 2

[0072]

[0073] Example 2

[0074] The following is for reference Figures 3 to 4 Describes an optical imaging lens according to Embodiment 2 of this application. Figure 3 A schematic diagram of the structure of an optical imaging lens according to Embodiment 2 of this application is shown.

[0075] like Figure 3 As shown, the optical imaging lens according to an exemplary embodiment of this application includes, in sequence 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.

[0076] The first lens E1 has negative optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has positive optical power, with its object-side surface S3 being convex and its image-side surface S4 being convex. The third lens E3 has negative optical power, with its object-side surface S5 being convex and its image-side surface S6 being concave. The fourth lens E4 has positive optical power, with its object-side surface S7 being concave and its image-side surface S8 being convex. The fifth lens E5 has negative optical power, with its object-side surface S9 being convex and its image-side surface S10 being concave. The sixth lens E6 has negative optical power, with its object-side surface S11 being convex and its image-side surface S12 being concave. The filter E7 has an object-side surface S13 and an image-side surface S14. Light from the object passes sequentially through surfaces S1 to S14 and is finally imaged onto the imaging surface S15.

[0077] Table 3 shows the surface type, radius of curvature, thickness, and material of each lens in the optical imaging lens of Example 2, wherein the units for radius of curvature and thickness are millimeters (mm).

[0078] Table 3

[0079]

[0080] In Table 3, the object-side surface and image-side surface of any one of the lenses E1, E2, E3, E4, E5, and E6 are Q-type aspherical surfaces. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formulas:

[0081]

[0082] Where Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, r is the radial coordinate of the aspherical surface, c is the curvature of the vertex of the aspherical surface, 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 higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28 and A30 of each aspherical surface that can be used in the second embodiment.

[0083] Table 4

[0084]

[0085] Example 3

[0086] The following is for reference Figures 5 to 6 Describes an optical imaging lens according to Embodiment 3 of this application. Figure 5 A schematic diagram of the structure of an optical imaging lens according to Embodiment 3 of this application is shown.

[0087] like Figure 5 As shown, the optical imaging lens according to an exemplary embodiment of this application includes, in sequence 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.

[0088] The first lens E1 has negative optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has positive optical power, with its object-side surface S3 being convex and its image-side surface S4 being convex. The third lens E3 has negative optical power, with its object-side surface S5 being convex and its image-side surface S6 being concave. The fourth lens E4 has positive optical power, with its object-side surface S7 being concave and its image-side surface S8 being convex. The fifth lens E5 has negative optical power, with its object-side surface S9 being convex and its image-side surface S10 being concave. The sixth lens E6 has negative optical power, with its object-side surface S11 being convex and its image-side surface S12 being concave. The filter E7 has an object-side surface S13 and an image-side surface S14. Light from the object passes sequentially through surfaces S1 to S14 and is finally imaged onto the imaging surface S15.

[0089] Table 5 shows the surface type, radius of curvature, thickness, and material of each lens in the optical imaging lens of Example 3, wherein the units for radius of curvature and thickness are millimeters (mm).

[0090] Table 5

[0091]

[0092] In Table 5, the object-side surface and image-side surface of any one of the lenses E1, E2, E3, E4, E5, and E6 are Q-type aspherical surfaces. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formulas:

[0093]

[0094] Where Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, r is the radial coordinate of the aspherical surface, c is the curvature of the vertex of the aspherical surface, 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 higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28 and A30 of each aspherical surface that can be used in the third embodiment.

[0095] Table 6

[0096]

[0097] Example 4

[0098] The following is for reference Figures 7 to 8 Describes an optical imaging lens according to Embodiment 4 of this application. Figure 7 A schematic diagram of the structure of an optical imaging lens according to Embodiment 4 of this application is shown.

[0099] like Figure 7 As shown, the optical imaging lens according to an exemplary embodiment of this application includes, in sequence 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.

[0100] The first lens E1 has negative optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has positive optical power, with its object-side surface S3 being convex and its image-side surface S4 being convex. The third lens E3 has positive optical power, with its object-side surface S5 being concave and its image-side surface S6 being convex. The fourth lens E4 has negative optical power, with its object-side surface S7 being convex and its image-side surface S8 being concave. The fifth lens E5 has positive optical power, with its object-side surface S9 being convex and its image-side surface S10 being convex. The sixth lens E6 has negative optical power, with its object-side surface S11 being convex and its image-side surface S12 being concave. The filter E7 has an object-side surface S13 and an image-side surface S14. Light from the object passes sequentially through surfaces S1 to S14 and is finally imaged onto the imaging surface S15.

[0101] Table 7 shows the surface type, radius of curvature, thickness, and material of each lens in the optical imaging lens of Example 4, wherein the units for radius of curvature and thickness are millimeters (mm).

[0102] Table 7

[0103]

[0104] In Table 7, the object-side surface and image-side surface of any one of the lenses E1, E2, E3, E4, E5, and E6 are Q-type aspherical surfaces. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formulas:

[0105]

[0106] Where Z is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, r is the radial coordinate of the aspherical surface, c is the curvature of the vertex of the aspherical surface, 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 higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28 and A30 of each aspherical surface that can be used in the fourth embodiment.

[0107] Table 8

[0108]

[0109] In Examples 1-4, the basic data is as follows:

[0110] Table 9

[0111]

[0112] In Examples 1-4, each conditional expression satisfies the conditions in the table below:

[0113] Table 10

[0114]

[0115] A camera module includes at least an optical lens, in which the aforementioned large-aperture imaging optical system is installed. By selecting six aspherical lenses and rationally configuring the refractive power and surface shape of each lens, it features an ultra-wide-angle lens, small overall size, and a large aperture. The structure is compact, easy to manufacture and install. At the same time, the large aperture configuration can increase the amount of light entering the optical system and achieve higher image quality.

[0116] 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 large-aperture imaging optical system, characterized in that: Along the optical axis from the object plane to the image plane, it consists 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 object side is convex while its image side is concave. The second lens has positive optical power, and its object side is convex, as is its image side; The third and fifth lenses have negative optical power, the fourth lens has positive optical power, the object-side surface of the third lens is convex and the image-side surface is concave, the object-side surface of the fourth lens is concave and the image-side surface is convex, and the object-side surface of the fifth lens is convex and the image-side surface is concave; or the third and fifth lenses have positive optical power, the fourth lens has negative optical power, the object-side surface of the third lens is concave and the image-side surface is convex, the object-side surface of the fourth lens is convex and the image-side surface is concave, and the object-side surface of the fifth lens is convex and the image-side surface is convex. The sixth lens has negative optical power, and its object side is convex while its image side is concave. The imaging optical system satisfies the following relationship: 1.83 ≤ |(f4-f5) / (f4+f5)| ≤ 2.34; 1.04 ≤ f345 / f ≤ 1.96; 2.65 ≤ (f23+f456) / f ≤3.78; 2.87≤CT3 / |SAG6|≤3.08; 4.30 ≤ Overall length of the optical system ≤ 5.01 mm; 5.66 ≤ TTL / (CT1+CT2-T12) ≤7.84; 1.88 ≤ BFL / (T12+ T23) ≤ 3.24; 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, fourth, and fifth lenses, 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, f is the effective focal length of the imaging optical system, 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 in the direction parallel to the optical axis, TTL is the axial 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 and second lenses on 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 direction of the optical axis, and T23 is the air gap between the second and third lenses on the optical axis.

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

3. The large aperture imaging optical system according to claim 1, characterized in that, The imaging optical system satisfies the following relationship: 0<|(SAG1-SAG3)| / (SAG1+SAG3)<1.8; Wherein, SAG1 is the distance from the point where the maximum effective aperture of the first lens surface is parallel to the optical axis to the point where the first lens surface intersects with the optical axis, and SAG3 is the distance from the point where the maximum effective aperture of the second lens surface is parallel to the optical axis to the point where the second lens surface intersects with the optical axis.

4. The large aperture imaging optical system according to claim 1, characterized in that, The first lens, the second lens, the third lens, the fifth lens, and the sixth lens are aspherical lenses, and they are all separated by air gaps.

5. The large aperture imaging optical system according to claim 1, characterized in that, The F-number of the imaging optical system is ≤2.

2.

6. The large aperture imaging optical system according to claim 1, characterized in that, The following relationship must be satisfied: the aperture is positioned between the first lens and the second lens.

7. A camera module, comprising at least an optical lens, characterized in that: The optical lens is equipped with the large aperture imaging optical system as described in any one of claims 1-6.

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