Long-focus imaging optical system and camera module applying same

Abstract

The invention provides a long-focus imaging optical system and a camera module applying the same, the long-focus imaging optical system is composed of six lenses, the first lens has positive focal power, the object side surface of the first lens is a convex surface, the second lens has negative focal power, the image side surface of the second lens is a concave surface, the third lens has positive focal power, the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a concave surface; the fourth lens has positive focal power, the fifth lens has focal power, the object side surface of the fifth lens is a convex surface, the image side surface of the fifth lens is a concave surface, the sixth lens has focal power, the image side surface of the sixth lens is a concave surface, and the refractive power and the surface type of each lens are reasonably configured, so that the optical lens has the characteristics of long focus, small overall size 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] The present application relates to the field of optical imaging, and in particular to a telephoto imaging optical system and a camera module using the same. Background Art

[0002] With the continuous development of science and technology, people have higher and higher requirements for the imaging quality of optical lenses. Not only do they require optical lenses to be lighter, thinner and smaller, but as the demand for long-distance shooting increases, camera lenses need to have long focal lengths. However, problems such as insufficient clarity and poor image quality are prone to occur, resulting in unsatisfactory long-distance photography effects. In order to achieve higher imaging quality, the optical lens needs to increase the number of lenses to correct aberrations. However, the increase in the number of lenses increases the difficulty of assembly and the size of the optical lens. Therefore, how to increase the focal length and improve the image quality while meeting the requirements of miniature design so that distant scenes can be clearly imaged on the imaging surface should be the research and development direction of the industry. Summary of the invention

[0003] The present application aims to solve the problems of insufficient clarity, poor image quality and large size in existing optical imaging systems, and to provide a device with the characteristics of long focus, small overall size and large aperture, while also being able to better capture object detail information, improve the ability of the optical lens to capture details of the photographed object, improve the image quality of the optical lens, and improve the resolution and imaging clarity of the optical lens to meet people's requirements for high-definition imaging with a long-focus optical lens.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions: A telephoto imaging optical system, which is composed of an aperture, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens in sequence from the object plane to the image plane along the optical axis; The first lens has positive optical power, and its object side surface is convex; The second lens has negative optical power, and its image side surface is concave; The third lens has positive refractive power, its object side surface is convex, and its image side surface is concave; The fourth lens has positive refractive power; The fifth lens has optical power, and its object side surface is convex, and its image side surface is concave; The sixth lens has optical power, and its image side surface is concave.

[0005] Preferably, the telephoto imaging optical system satisfies the following relationship: 0<|(f3+f6) / f6|<2.6; 3.0 <f45 / f<5.0; 7.5 <f / (T23+T56)<11; Wherein, f3 is the effective focal length of the third lens, f6 is the effective focal length of the sixth lens, f45 is the effective combined focal length of the fourth lens and the fifth lens, f is the effective focal length of the optical imaging system, T23 is the air spacing between the second lens and the third lens on the optical axis, and T56 is the air spacing between the fifth lens and the sixth lens on the optical axis.

[0006] Preferably, the telephoto imaging optical system satisfies the following relationship: 7.5 <f / (T23+T56)<11; Wherein, f is the effective focal length of the optical imaging system, T23 is the air interval between the second lens and the third lens on the optical axis, and T56 is the air interval between the fifth lens and the sixth lens on the optical axis.

[0007] Preferably, the telephoto 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 telephoto imaging optical system, and ImgH is half of the diagonal length of the effective pixel area on the imaging surface.

[0008] Preferably, the telephoto imaging optical system satisfies the following relationship: 0<|R8| / R2<2.4; 0.4<|(R11+R12) / R11|<2.1; Among them, R2 is the curvature radius of the image side of the first lens, R8 is the curvature radius of the image side of the fourth lens, R11 is the curvature radius of the object side of the sixth lens, and R12 is the curvature radius of the image side of the sixth lens.

[0009] Preferably, the telephoto imaging optical system satisfies the following relationship: 14mm<(FNO*f*ImgH) / TTL<16mm; Wherein, f is the effective focal length of the optical imaging system, FNO is the F number of the optical imaging lens, ImgH is half of the diagonal length of the effective pixel area on the imaging plane, and TTL is the axial distance from the object side of the first lens to the imaging plane.

[0010] Preferably, the telephoto imaging optical system satisfies the following relationship: 3 <EPD / (CT2+CT3)<5; 5.0<(CT1+CT2+CT3+CT4+CT5+CT6) / CT3<7.2; Among them, EPD is the entrance pupil diameter of the optical imaging system, 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, CT3 is the center thickness of the third lens on the optical axis, CT4 is the center thickness of the fourth lens on the optical axis, CT5 is the center thickness of the fifth lens on the optical axis, and CT6 is the center thickness of the sixth lens on the optical axis.

[0011] Preferably, the telephoto imaging optical system satisfies the following relationship: 3.5 <DT31 / SAG5<4.2; Among them, DT31 is half of the maximum effective aperture of the objective side of the third lens, and SAG5 is the distance from the maximum effective aperture of the objective side of the third lens to the intersection of the objective side of the first lens and the optical axis in the direction parallel to the optical axis.

[0012] Preferably, the telephoto imaging optical system has an F number ≤ 2.2 and an overall length ≤ 19 mm.

[0013] Preferably, the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are aspherical lenses.

[0014] On the other hand, an embodiment of the present application further provides a camera module, comprising at least an optical lens, wherein the above-mentioned telephoto imaging optical system is installed in the optical lens.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a telephoto imaging optical system and a camera module applied thereto, which are composed of 6 lenses, wherein a first lens has positive focal power, and an object side surface thereof is a convex surface, a second lens has negative focal power, and an image side surface thereof is a concave surface, the third lens has positive focal power, and an object side surface thereof is a convex surface, and an image side surface thereof is a concave surface, the fourth lens has positive focal power, the fifth lens has focal power, and an object side surface thereof is a convex surface, and an image side surface is a concave surface, and the sixth lens has focal power, and an image side surface thereof is a concave surface. By reasonably configuring the refractive power and surface shape of each lens, the optical lens can have the characteristics of telephoto, small overall size and large aperture, and can also better capture object detail information, thereby improving the optical lens's ability to capture details of the photographed object, improving the image quality of the optical lens, and improving the resolution and imaging clarity of the optical lens, so as to meet people's high-definition imaging requirements for a telephoto optical lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for describing the embodiments are briefly introduced below.

[0017] Figure 1It is a structural schematic diagram of an optical imaging system or camera module according to Embodiment 1 of the present application; Figure 2 is the axial chromatic aberration, astigmatism and distortion curve of the optical imaging system or camera module in Example 1 of the present application; Figure 3 It is a structural schematic diagram of an optical imaging system or camera module according to Embodiment 2 of the present application; Figure 4 is the axial chromatic aberration, astigmatism and distortion curve of the optical imaging system or camera module in Example 2 of the present application; Figure 5 It is a structural schematic diagram of an optical imaging system or camera module according to Embodiment 3 of the present application; Figure 6 The axial chromatic aberration, astigmatism and distortion curves of the optical imaging system or camera module of Example 3 of the present application; Figure 7 It is a structural schematic diagram of an optical imaging system or camera module according to Embodiment 4 of the present application; Figure 8 These are the axial chromatic aberration, astigmatism and distortion curves of the optical imaging system or camera module of Example 4 of the present application. DETAILED DESCRIPTION

[0018] like Figure 1-8 As shown, the present application provides a telephoto imaging optical system, which is composed of an aperture, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens in sequence from the object plane to the image plane along the optical axis; The first lens has positive optical power, and its object side surface is convex; The second lens has negative optical power, and its image side surface is concave; The third lens has positive refractive power, its object side surface is convex, and its image side surface is concave; The fourth lens has positive refractive power; The fifth lens has optical power, and its object side surface is convex, and its image side surface is concave; The sixth lens has optical power, and its image side surface is concave.

[0019] The embodiment of the present invention discloses a telephoto optical system. 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 telephoto, small overall size and large aperture, and at the same time can better capture the detail 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, and improve the resolution and imaging clarity of the optical lens, so as to meet people's high-definition imaging requirements for telephoto optical lenses.

[0020] Furthermore, the telephoto imaging optical system satisfies the following relationship: 14 mm < (FNO * f * ImgH) / TTL < 16 mm, where f is the effective focal length of the optical imaging system, FNO is the F-number of the optical imaging lens, ImgH is half of the diagonal length of the effective pixel region on the imaging surface, 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 telephoto, large aperture, and miniaturization characteristics, enabling the optical system to have the characteristics of large aperture and miniaturization while meeting the telephoto requirements. When it is lower than the lower limit of the relational expression, on the basis of ensuring the miniaturization of the optical system, FNO * f * ImgH further increases, which is not conducive to the optical lens meeting the large aperture characteristic; when it is lower than the lower limit of the relational expression, on the basis of ensuring the large aperture of the optical system, it is difficult for the optical system to meet the miniaturization characteristic and it is difficult to obtain good imaging resolution.

[0021] Furthermore, the telephoto imaging optical system satisfies the following relationship: 2.8° / mm < HFOV / ImagH < 3.4° / mm; where 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 region on the imaging surface. By controlling the ratio of half of the maximum field of view angle of the optical system to half of the diagonal length of the effective pixel region on the imaging surface, the optical system also has telephoto characteristics under a certain target surface, enabling the imaging lens to have a good telephoto imaging function, thereby increasing the imaging range of the optical system for distant objects and presenting a clearer shooting effect. When exceeding the upper limit of the above relational expression, the field of view angle of the optical lens is too large, which is not conducive to the optical lens maintaining a long focal length to achieve a telephoto effect, and at the same time, it will also cause excessive off-axis field distortion, resulting in a distortion phenomenon in the periphery of the image; when lower than the lower limit of the above relational expression, the focal length of the optical lens is too long, which is not conducive to meeting the field of view angle range of the optical lens, and it is impossible to obtain sufficient object space information, affecting the shooting quality of the optical lens.

[0022] Furthermore, the telephoto imaging optical system satisfies the following relationship: 0 < |R8| / R2 < 2.4, where R2 is the radius of curvature of the image side surface of the first lens, and R8 is the radius of curvature of the image side surface of the fourth lens. By limiting the ratio of the radius of curvature of the image side surface of the first lens to the radius of curvature of the image side surface of the fourth lens, the reasonable surface shape trends of the first lens and the fourth lens can be controlled, and the good deflection effect and aberration correction ability for the light rays in the central field of view and the peripheral field of view can be fully realized, enabling better balance of the aberrations in the entire field of view.

[0023] Furthermore, the telephoto imaging optical system satisfies the following relationship: 0.4 < |(R11 + R12) / R11| < 2.1, where R11 is the curvature radius of the object side of the sixth lens, and R12 is the curvature radius of the image side of the sixth lens. By constraining the ratio of the curvature radii of the object side and the image side of the sixth lens, the surface shape of the sixth lens will not be too curved, and it has a high degree of freedom during the design process, which is beneficial to better correcting the astigmatism and field curvature of the optical lens, reducing the risk of ghost images, and improving the imaging quality of the optical lens. In addition, it is also beneficial to the processability of the sixth lens and reduces the difficulty of forming and assembling the sixth lens.

[0024] Furthermore, the telephoto imaging optical system satisfies the following relationship: 0 < |(f3 + f6) / f6| < 2.6, where f3 is the effective focal length of the third lens, and f6 is the effective focal length of the sixth lens. By reasonably allocating the ratio of the optical power of the third lens and the sixth lens optical components within a reasonable range, it is possible to balance the remaining spherical aberration after balancing to balance the spherical aberration generated by the first lens and the second lens, and then precisely control the axial field aberration of the system, thereby improving the overall resolution of the optical lens. At the same time, it is also beneficial to compress the size of the rear group lenses of the optical system, which helps the miniaturization design of the imaging lens.

[0025] Furthermore, the telephoto imaging optical system satisfies the following relationship: 3.0 < f45 / f < 5.0, where f45 is the effective combined focal length of the fourth lens and the fifth lens, and f is the effective focal length of the optical imaging system. The fourth lens provides positive refractive power for the optical system, and the fifth lens provides refractive power for the optical system. By using the structure of two lenses with refractive power glued together, it is beneficial to the mutual correction of aberrations. Exceeding the upper limit of the relational expression, the refractive power of the glued lens combination is too small, which is likely to generate large marginal aberrations and chromatic aberrations, and is not conducive to improving the resolution performance; exceeding the lower limit of the relational expression, the overall refractive power of the fifth lens and the fifth lens is too strong, which makes the lens group prone to serious astigmatism, and is not conducive to the improvement of imaging quality.

[0026] Furthermore, the telephoto imaging optical system satisfies the following relationship: 7.5 < f / (T23 + T56) < 11, where f is the effective focal length of the optical imaging system, T23 is the air separation between the second lens and the third lens on the optical axis, and T56 is the air separation between the fifth lens and the sixth lens on the optical axis. By controlling the ratio of the effective focal length f of the optical imaging lens to the sum of the air separations between the second lens and the third lens and between the fifth lens and the sixth lens on the optical axis within a reasonable range, while meeting the telephoto performance, it can ensure that the axial distances between the second lens and the third lens, and between the fifth lens and the sixth lens are not too small. This is beneficial to the assembly process, avoiding light interference due to the two lenses being too close, and at the same time being able to adjust the field curvature and astigmatism of the camera lens, reducing the sensitivity of the lens, weakening the ghost image energy between the second lens and the sixth lens, and improving the imaging quality of the lens.

[0027] Furthermore, the telephoto imaging optical system satisfies the following relationship: 3 < EPD / (CT2 + CT3) < 5, where EPD is the entrance pupil diameter of the optical imaging system, CT2 is the central thickness of the second lens on the optical axis, and CT3 is the central thickness of the third lens on the optical axis. By limiting the range of the above sub-expression, it can ensure that the central thicknesses of the second lens and the third lens are not too thin, which is beneficial to the processing and assembly processes of the lens. If it exceeds the upper limit of the relationship, the second lens and the third lens are too thin, which easily leads to problems such as difficult processing and lens deformation, thus affecting the imaging quality of the lens; if it is lower than the lower limit of the relationship, the risk of ghost images of the second lens and the third lens increases, and it is not conducive to reducing the distortion and field curvature of the optical system, and is not conducive to improving the imaging quality of the lens.

[0028] Furthermore, the telephoto imaging optical system satisfies the following relationship: 5.0 < (CT1 + CT2 + CT3 + CT4 + CT5 + CT6) / CT3 < 7.2, where 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, CT3 is the central thickness of the third lens on the optical axis, CT4 is the central thickness of the fourth lens on the optical axis, CT5 is the central thickness of the fifth lens on the optical axis, and CT6 is the central thickness of the sixth lens on the optical axis. When the above conditional expression is satisfied, it can reasonably configure the ratio of the sum of the central thicknesses of each lens in the optical system to the central thickness of the third lens, which is beneficial to shortening the total length of the optical system, making the structure of the optical system more compact, and thus realizing miniaturized design; at the same time, it is also beneficial to reducing the eccentricity sensitivity of the third lens, which is beneficial to the production and assembly of the optical system. If it exceeds the upper limit of the above conditional expression, the sum of the central thicknesses of each lens is too large, which is not conducive to realizing a compact structure and miniaturized design; if it is lower than the lower limit of the above conditional expression, the central thickness of the third lens is too large, resulting in an increase in the eccentricity sensitivity of the third lens, which is not conducive to the production and assembly of the third lens.

[0029] Furthermore, the telephoto imaging optical system satisfies the following relationship: 3.5 < DT31 / sag5 < 4.2, where DT31 is half of the maximum effective clear aperture of the object side surface of the third lens, and SAG5 is the distance parallel to the optical axis from the maximum effective clear aperture of the object side surface of the third lens to the intersection of the object side surface of the first lens and the optical axis. Satisfying the above relationship is beneficial to avoiding excessive bending of the object side surface of the first lens, reducing the processing difficulty of the first lens, avoiding the problem of uneven coating caused by excessive bending of the first lens, facilitating the incidence of large-angle light rays onto the optical system, thereby ensuring the imaging quality of the optical system. By satisfying the upper limit of the relationship, it is possible to avoid the object side surface of the first lens from being too flat and reduce the risk of ghosting.

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

[0031] As Figure 1 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: STO, the first lens E1, the second lens E2, the third lens E3, the fourth lens E4, the fifth lens E5, the sixth lens E6, the infrared filter E7, and the imaging surface S15.

[0032] The first lens E1 has a positive 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 negative optical power, its object side surface S3 is a convex surface, and its image side surface S4 is a concave surface. The third lens E3 has a positive 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 convex 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 concave 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 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, the object side surface and the image side surface of 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 are all Q-type aspherical surfaces, and the surface shape of each aspherical lens can be defined by but not limited to the following aspherical formula:

[0036] Wherein, 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 cone coefficient, Am is the aspherical coefficient, rmax is the maximum radial radius coordinate, and u=r / rmax. Table 2 shows the cone coefficients and high-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 Example 1.

[0037] Table 2

[0038] Figure 2 The axial chromatic aberration, astigmatism and distortion curves of the optical imaging lens of Example 1 are shown. Axial chromatic aberration indicates that light of different wavelengths deviates from the focal point after passing through the lens; astigmatism indicates the meridional image curvature and sagittal image curvature; distortion indicates the distortion magnitude value corresponding to different image heights. The optical imaging lens given in Example 1 can achieve good imaging quality.

[0039] Embodiment 2 The following reference Figure 3 to Figure 4 An optical imaging lens according to Embodiment 2 of the present application is described. Figure 3 A schematic structural diagram of an optical imaging lens according to Embodiment 2 of the present application is shown.

[0040] like Figure 3 As shown, the optical imaging lens according to an exemplary embodiment of the present application includes, in order from the object side to the image side along the optical axis: STO, a first lens E1, 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.

[0041] The first lens E1 has positive focal power, and its object side surface S1 is convex, and its image side surface S2 is convex. The second lens E2 has negative focal power, and its object side surface S3 is concave, and its image side surface S4 is concave. The third lens E3 has positive focal power, and its object side surface S5 is convex, and its image side surface S6 is concave. The fourth lens E4 has positive focal power, and its object side surface S7 is concave, and its image side surface S8 is convex. The fifth lens E5 has positive focal power, and its object side surface S9 is convex, and its image side surface S10 is concave. The sixth lens E6 has negative focal power, and 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. The light from the object passes through each surface S1 to S14 in sequence and is finally imaged on the imaging surface S15.

[0042] Table 3 shows the surface type, curvature radius, thickness and material of each lens of the optical imaging lens of Example 2, wherein the units of the curvature radius and thickness are both millimeters (mm).

[0043] Table 3

[0044] In Table 3, the object side surface and the image side surface of 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 are all Q-type aspherical surfaces, and the surface shape of each aspherical lens can be defined by but not limited to the following aspherical formula:

[0045] 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 cone coefficient, Am is the aspherical coefficient, and r is the curvature of the vertex of the aspherical surface. max is the maximum radial radius coordinate, u=r / r max Table 4 shows the conic coefficients and high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28 and A30 of each aspheric surface that can be used in Example 2.

[0046] Table 4

[0047] Figure 4 The axial chromatic aberration, astigmatism and distortion curves of the optical imaging lens of Example 2 are shown. Axial chromatic aberration indicates that light of different wavelengths deviates from the focal point after passing through the lens; astigmatism indicates the meridional image curvature and sagittal image curvature; distortion indicates the distortion magnitude value corresponding to different image heights. The optical imaging lens given in Example 2 can achieve good imaging quality.

[0048] Embodiment 3 The following reference Figures 5 and 6 An optical imaging lens according to Embodiment 3 of the present application is described. Figure 5 A schematic structural diagram of an optical imaging lens according to Embodiment 3 of the present application is shown.

[0049] like Figure 5 As shown, the optical imaging lens according to an exemplary embodiment of the present application includes, in order from the object side to the image side along the optical axis: STO, a first lens E1, 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.

[0050] The first lens E1 has positive focal power, and its object side surface S1 is convex, and its image side surface S2 is concave. The second lens E2 has negative focal power, and its object side surface S3 is convex, and its image side surface S4 is concave. The third lens E3 has positive focal power, and its object side surface S5 is convex, and its image side surface S6 is concave. The fourth lens E4 has positive focal power, and its object side surface S7 is convex, and its image side surface S8 is convex. The fifth lens E5 has negative focal power, and its object side surface S9 is convex, and its image side surface S10 is concave. The sixth lens E6 has negative focal power, and its object side surface S11 is concave, and its image side surface S12 is concave. The filter E7 has an object side surface S13 and an image side surface S14. The light from the object passes through each surface S1 to S14 in sequence and is finally imaged on the imaging surface S15.

[0051] Table 5 shows the surface type, curvature radius, thickness and material of each lens of the optical imaging lens of Example 3, wherein the units of the curvature radius and thickness are both millimeters (mm).

[0052] Table 5

[0053] In Table 5, the object side surface and the image side surface of 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 are all Q-type aspherical surfaces, and the surface shape of each aspherical lens can be defined by but not limited to the following aspherical formula:

[0054] 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 cone coefficient, Am is the aspherical coefficient, and r is the curvature of the vertex of the aspherical surface. max is the maximum radial radius coordinate, u=r / r max Table 6 shows the conic coefficients and high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28 and A30 of the aspheric surfaces that can be used in Example 3.

[0055] Table 6

[0056] Figure 6 The axial chromatic aberration, astigmatism and distortion curves of the optical imaging lens of Example 3 are shown. Axial chromatic aberration indicates that light of different wavelengths deviates from the focal point after passing through the lens; astigmatism indicates the meridional image curvature and sagittal image curvature; distortion indicates the distortion magnitude value corresponding to different image heights. The optical imaging lens given in Example 3 can achieve good imaging quality.

[0057] Embodiment 4: The following reference Figures 7 and 8 An optical imaging lens according to Embodiment 4 of the present application is described. Figure 7 A schematic structural diagram of an optical imaging lens according to Embodiment 4 of the present application is shown.

[0058] like Figure 7 As shown, the optical imaging lens according to an exemplary embodiment of the present application includes, in order from the object side to the image side along the optical axis: STO, a first lens E1, 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.

[0059] The first lens E1 has positive focal power, and its object side surface S1 is convex, and its image side surface S2 is concave. The second lens E2 has negative focal power, and its object side surface S3 is convex, and its image side surface S4 is concave. The third lens E3 has positive focal power, and its object side surface S5 is convex, and its image side surface S6 is concave. The fourth lens E4 has positive focal power, and its object side surface S7 is convex, and its image side surface S8 is concave. The fifth lens E5 has negative focal power, and its object side surface S9 is convex, and its image side surface S10 is concave. The sixth lens E6 has positive focal power, and 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. The light from the object passes through each surface S1 to S14 in sequence and is finally imaged on the imaging surface S15.

[0060] Table 7 shows the surface type, curvature radius, thickness and material of each lens of the optical imaging lens of Example 4, wherein the units of the curvature radius and thickness are both millimeters (mm).

[0061] Table 7

[0062] In Table 7, the object side surface and the image side surface of 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 are all Q-type aspherical surfaces, and the surface shape of each aspherical lens can be defined by but not limited to the following aspherical formula:

[0063] 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 cone coefficient, Am is the aspherical coefficient, and r is the curvature of the vertex of the aspherical surface. max is the maximum radial radius coordinate, u=r / r max Table 8 shows the conic coefficients and high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28 and A30 of the aspheric surfaces that can be used in Example 4.

[0064] Table 8

[0065] Figure 8 The axial chromatic aberration, astigmatism and distortion curves of the optical imaging lens of Example 4 are shown. Axial chromatic aberration indicates the deviation of light of different wavelengths from the focal point after passing through the lens; astigmatism indicates the meridional image curvature and sagittal image curvature; distortion indicates the distortion magnitude value corresponding to different image heights. The optical imaging lens given in Example 4 can achieve good imaging quality.

[0066] In Examples 1-4, the basic data are as follows: Table 9

[0067] In Examples 1-4, each conditional expression satisfies the conditions in the following table: Table 10

[0068] A camera module comprises at least an optical lens, in which the above-mentioned telephoto imaging optical system is installed. The camera module has the characteristics of telephoto, small overall size, low cost and large aperture, compact structure, and is easy to process and install. At the same time, the configuration of large aperture can increase the amount of light entering the optical system and achieve higher imaging quality.

[0069] As described above, one or more implementation methods are provided in combination with specific contents, and the specific implementation of the present invention is not limited to these descriptions. Any similarity or similarity with the method, structure, etc. of the present invention, or any technical deduction or replacement based on the concept of the present invention, shall be regarded as the protection scope of the present invention.

Claims

1. A telephoto imaging optical system, characterized in that: Along the optical axis, from the object plane to the image plane, it is composed of an aperture, 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 positive optical power, and its object side surface is convex; The second lens has negative optical power, and its image side surface is concave; The third lens has positive refractive power, its object side surface is convex, and its image side surface is concave; The fourth lens has positive refractive power; The fifth lens has optical power, and its object side surface is convex, and its image side surface is concave; The sixth lens has optical power, and its image side surface is concave; The telephoto imaging optical system satisfies the following relationship: 0 < |(f3+f6) / f6| < 2.6; 3.0 < f45 / f < 5.0; Among them, f3 is the effective focal length of the third lens, f6 is the effective focal length of the sixth lens, f45 is the effective combined focal length of the fourth lens and the fifth lens, and f is the effective focal length of the optical imaging system.

2. The telephoto imaging optical system according to claim 1, characterized in that: The telephoto imaging optical system satisfies the following relationship: 7.5 < f / (T23+T56) < 11; Wherein, f is the effective focal length of the optical imaging system, T23 is the air interval between the second lens and the third lens on the optical axis, and T56 is the air interval between the fifth lens and the sixth lens on the optical axis.

3. The telephoto imaging optical system according to claim 1, characterized in that: The telephoto 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 telephoto imaging optical system, and ImgH is half of the diagonal length of the effective pixel area on the imaging surface.

4. The telephoto imaging optical system according to any one of claims 1 to 3, characterized in that: The telephoto imaging optical system satisfies the following relationship: 0 < |R8| / R2 < 2.4; 0.4 < |(R11+R12) / R11| < 2.1; Among them, R2 is the curvature radius of the image side of the first lens, R8 is the curvature radius of the image side of the fourth lens, R11 is the curvature radius of the object side of the sixth lens, and R12 is the curvature radius of the image side of the sixth lens.

5. The telephoto imaging optical system according to any one of claims 1 to 3, characterized in that: The telephoto imaging optical system satisfies the following relationship: 14mm < (FNO*f*ImgH) / TTL < 16mm; Wherein, f is the effective focal length of the optical imaging system, FNO is the F number of the optical imaging lens, ImgH is half of the diagonal length of the effective pixel area on the imaging plane, and TTL is the axial distance from the object side of the first lens to the imaging plane.

6. The telephoto imaging optical system according to any one of claims 1 to 3, characterized in that: The telephoto imaging optical system satisfies the following relationship: 3 < EPD / (CT2+CT3) < 5; 5.0 < (CT1+CT2+CT3+CT4+CT5+CT6) / CT3 < 7.2; Among them, EPD is the entrance pupil diameter of the optical imaging system, 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, CT3 is the center thickness of the third lens on the optical axis, CT4 is the center thickness of the fourth lens on the optical axis, CT5 is the center thickness of the fifth lens on the optical axis, and CT6 is the center thickness of the sixth lens on the optical axis.

7. The telephoto imaging optical system according to any one of claims 1 to 3, characterized in that: The telephoto imaging optical system satisfies the following relationship: 3.5 < DT31 / SAG5 < 4.2; Among them, DT31 is half of the maximum effective aperture of the objective side of the third lens, and SAG5 is the distance from the maximum effective aperture of the objective side of the third lens to the intersection of the objective side of the first lens and the optical axis in the direction parallel to the optical axis.

8. The telephoto imaging optical system according to claim 1, wherein: The telephoto imaging optical system has an F number of ≤2.2 and an overall length of ≤19 mm.

9. The telephoto imaging optical system according to claim 1, characterized in that: The first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are aspherical lenses.

10. A camera module, comprising at least an optical lens, characterized in that: The optical lens is equipped with the telephoto imaging optical system according to any one of claims 1 to 9.

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