Long-focus imaging optical system and camera module using the same

Abstract

This invention provides a telephoto imaging optical system and its application in a camera module, comprising six lenses. The first lens has positive optical power and a convex object-side surface; the second lens has negative optical power and a concave image-side surface; the third lens has positive optical power, a convex object-side surface, and a concave image-side surface; the fourth lens has positive optical power; the fifth lens has optical power, a convex object-side surface, and a concave image-side surface; and the sixth lens has optical power and a concave image-side surface. By rationally configuring the refractive power and surface shape of each lens, the optical lens can achieve the characteristics of telephoto, small overall size, and large aperture. Simultaneously, it can capture object details well, improving the optical lens's ability to capture details of the photographed object, enhancing image quality, and increasing resolution and image clarity to meet people's high-definition imaging requirements for telephoto optical lenses.

Description

Technical Field

[0001] This application relates to the field of optical imaging, and more particularly to a telephoto 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. Not only are optical lenses required to be thinner and smaller, but with the increasing demand for long-distance shooting, camera lenses need to have long focal lengths. However, this often leads to insufficient sharpness and poor image quality, resulting in unsatisfactory long-distance photography. To achieve higher image quality, optical lenses need to increase the number of lenses to correct aberrations. However, increasing the number of lenses increases the assembly difficulty and the size of the optical lens. Therefore, how to increase the focal length and improve image quality while meeting miniaturization requirements, so that distant scenes can be clearly imaged on the imaging plane, should be the research and development direction of the industry. Summary of the Invention

[0003] This application aims to address the problems of insufficient clarity, poor image quality, and large size in existing optical imaging systems. It provides a lens that features telephoto capabilities, a small overall size, and a large aperture, while also capturing object details effectively. This improves the lens's ability to capture details, enhances image quality, and increases resolution and image clarity to meet people's high-definition imaging requirements for telephoto lenses.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0005] A telephoto imaging optical system comprises, along the optical axis from the object plane to the image plane, an aperture stop, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens.

[0006] The first lens has positive optical power and its object side is convex.

[0007] The second lens has negative optical power, and its image-side surface is concave.

[0008] The third lens has positive optical power, and its object side is convex while its image side is concave.

[0009] The fourth lens has positive optical power;

[0010] The fifth lens has optical power, and its object side is convex and its image side is concave.

[0011] The sixth lens has optical power and its image-side surface is concave.

[0012] Preferably, the telephoto imaging optical system satisfies the following relationship:

[0013] 0 < |(f3+f6) / f6| < 2.6;

[0014] 3.0 <f45 / f<5.0;

[0015] 7.5 <f / (T23+T56)<11;

[0016] Where 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 and fifth lenses, f is the effective focal length of the optical imaging system, T23 is the air gap between the second and third lenses on the optical axis, and T56 is the air gap between the fifth and sixth lenses on the optical axis.

[0017] Preferably, the telephoto imaging optical system satisfies the following relationship:

[0018] 7.5 <f / (T23+T56)<11;

[0019] Where f is the effective focal length of the optical imaging system, T23 is the air gap between the second and third lenses on the optical axis, and T56 is the air gap between the fifth and sixth lenses on the optical axis.

[0020] Preferably, the telephoto imaging optical system satisfies the following relationship:

[0021] 2.8° / mm <HFOV / ImagH<3.4° / mm;

[0022] Where 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.

[0023] Preferably, the telephoto imaging optical system satisfies the following relationship:

[0024] 0 < |R8| / R2 < 2.4;

[0025] 0.4 < |(R11+R12) / R11| < 2.1;

[0026] Wherein, R2 is the radius of curvature of the image side of the first lens, R8 is the radius of curvature of the image side of the fourth lens, R11 is the radius of curvature of the object side of the sixth lens, and R12 is the radius of curvature of the image side of the sixth lens.

[0027] Preferably, the telephoto imaging optical system satisfies the following relationship:

[0028] 14mm < (FNO * f * ImgH) / TTL < 16mm;

[0029] 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 the diagonal length of the effective pixel area on the imaging surface, and TTL is the on-axis distance from the object side of the first lens to the imaging surface.

[0030] Preferably, the telephoto imaging optical system satisfies the following relationship:

[0031] 3 <EPD / (CT2+CT3)<5;

[0032] 5.0<(CT1+CT2+CT3+CT4+CT5+CT6) / CT3<7.2;

[0033] Wherein, 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.

[0034] Preferably, the telephoto imaging optical system satisfies the following relationship:

[0035] 3.5 <DT31 / SAG5<4.2;

[0036] Wherein, DT31 is half of the maximum effective light-transmitting aperture of the side surface of the third lens, and SAG5 is the distance from the maximum effective light-transmitting aperture of the side surface of the third lens to the intersection of the side surface of the first lens and the optical axis in the direction parallel to the optical axis.

[0037] Preferably, the F-number of the telephoto imaging optical system is ≤2.2, and the overall length is ≤19 mm.

[0038] Preferably, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are aspherical lenses.

[0039] On the other hand, embodiments of this application also provide a camera module, which includes at least an optical lens, and the aforementioned telephoto imaging optical system is installed in the optical lens.

[0040] Compared with the prior art, the beneficial effects of this application are as follows:

[0041] This invention provides a telephoto imaging optical system and its application in a camera module, comprising six lenses. The first lens has positive optical power and a convex object-side surface; the second lens has negative optical power and a concave image-side surface; the third lens has positive optical power, a convex object-side surface, and a concave image-side surface; the fourth lens has positive optical power; the fifth lens has optical power, a convex object-side surface, and a concave image-side surface; and the sixth lens has optical power and a concave image-side surface. By rationally configuring the refractive power and surface shape of each lens, the optical lens can achieve the characteristics of telephoto, small overall size, and large aperture. Simultaneously, it can capture object details well, improving the optical lens's ability to capture details of the photographed object, enhancing image quality, and increasing resolution and image clarity to meet people's high-definition imaging requirements for telephoto optical lenses. Attached Figure Description

[0042] 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.

[0043] Figure 1 This is a schematic diagram of the structure of the optical imaging system or camera module of Embodiment 1 of this application;

[0044] Figure 2 These are the on-axis chromatic aberration, astigmatism, and distortion curves of the optical imaging system or camera module of Embodiment 1 of this application;

[0045] Figure 3 This is a schematic diagram of the structure of the optical imaging system or camera module according to Embodiment 2 of this application;

[0046] Figure 4 These are the on-axis chromatic aberration, astigmatism, and distortion curves of the optical imaging system or camera module in Embodiment 2 of this application;

[0047] Figure 5 This is a schematic diagram of the structure of the optical imaging system or camera module of Embodiment 3 of this application;

[0048] Figure 6 These are the on-axis chromatic aberration, astigmatism, and distortion curves of the optical imaging system or camera module in Embodiment 3 of this application;

[0049] Figure 7 This is a schematic diagram of the structure of the optical imaging system or camera module of Embodiment 4 of this application;

[0050] Figure 8 These are the on-axis chromatic aberration, astigmatism, and distortion curves of the optical imaging system or camera module in Embodiment 4 of this application. Detailed Implementation

[0051] like Figure 1-8As shown, this application provides a telephoto imaging optical system, which is composed of an aperture stop, 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;

[0052] The first lens has positive optical power and its object side is convex.

[0053] The second lens has negative optical power, and its image-side surface is concave.

[0054] The third lens has positive optical power, and its object side is convex while its image side is concave.

[0055] The fourth lens has positive optical power;

[0056] The fifth lens has optical power, and its object side is convex and its image side is concave.

[0057] The sixth lens has optical power and its image-side surface is concave.

[0058] This invention discloses a telephoto optical system. 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 telephoto, small overall size and large aperture. At the same time, it can also capture object details better, 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 image clarity of the optical lens, so as to meet people's requirements for high-definition imaging of telephoto optical lenses.

[0059] Furthermore, the telephoto imaging optical system satisfies the following relationship: 14mm < (FNO*f*ImgH) / TTL < 16mm, 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 the diagonal length of the effective pixel area on the imaging plane, and TTL is the on-axis 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 telephoto, large aperture, and miniaturization characteristics, enabling the optical system to meet the requirements of telephoto while also possessing the characteristics of large aperture and miniaturization. When the value is below the lower limit of the relationship, FNO*f*ImgH further increases while ensuring the miniaturization of the optical system, which is not conducive to the optical lens meeting the characteristics of large aperture; when the value is below the lower limit of the relationship, while ensuring the large aperture of the optical system, it is difficult for the optical system to meet the characteristics of miniaturization, and it is difficult to obtain good imaging resolution.

[0060] 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 angle of the imaging optical system, and ImgH is half of the diagonal length of the effective pixel area on the imaging surface. By controlling the ratio of half of the maximum field angle of the optical system to half of the diagonal length of the effective pixel area 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 relationship, the field 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 distorted phenomenon in the periphery of the image; when lower than the lower limit of the above relationship, the focal length of the optical lens is too long, which is not conducive to meeting the field angle range of the optical lens, unable to obtain sufficient object space information, and affecting the shooting quality of the optical lens.

[0061] Furthermore, the telephoto imaging optical system satisfies the following relationship: 0 < |R8| / R2 < 2.4, where R2 is the curvature radius of the image side of the first lens, and R8 is the curvature radius of the image side of the fourth lens. By limiting the ratio of the curvature radius of the image side of the first lens to the curvature radius of the image side 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 and the edge field can be fully realized, enabling better balance of the aberrations in the entire field of view.

[0062] 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 on the surface during the design process, which is conducive 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 conducive to the processability of the sixth lens and reduces the difficulty of forming and assembling the sixth lens.

[0063] 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 optical components of the third lens and the sixth lens within a reasonable range, the remaining spherical aberration after balancing can balance the spherical aberration generated by the first lens and the second lens, thereby precisely controlling the axial field aberration of the system, improving the overall resolution of the optical lens, and also facilitating the compression of the size of the rear group lenses of the optical system, contributing to the miniaturized design of the imaging lens.

[0064] 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 for the mutual correction of aberrations. Exceeding the upper limit of the relationship, 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 relationship, the overall refractive power of the fifth lens and the fifth lens is too strong, making the lens group prone to serious astigmatism, and is not conducive to the improvement of imaging quality.

[0065] 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 gap between the second lens and the third lens on the optical axis, and T56 is the air gap between the fifth lens and the sixth lens on the optical axis. Controlling the ratio of the effective focal length f of the optical imaging lens, the air gap between the second lens and the third lens on the optical axis, and the sum of the air gaps between the fifth lens and the sixth lens on the optical axis within a reasonable range can ensure that the axial distances between the second lens and the third lens, and the fifth lens and the sixth lens are not too small while meeting the telephoto performance. This is beneficial for 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.

[0066] Further, 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 defining the range of the above sub-formula, it can be ensured that the central thicknesses of the second lens and the third lens are not too thin, which is beneficial to the lens processing and assembly processes. If it exceeds the upper limit of the relational formula, 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 relational formula, the ghosting risk 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, which is not conducive to improving the imaging quality of the lens.

[0067] Further, 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 formula is satisfied, it is possible to reasonably configure the ratio of the sum of the central thicknesses of each lens of 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 formula, 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 formula, 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.

[0068] Further, 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 of the third lens, and SAG5 is the distance parallel to the optical axis from the maximum effective clear aperture of the object side of the third lens to the intersection of the object side of the first lens and the optical axis. Satisfying the above relational formula is beneficial to avoiding the excessive curvature 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 the excessive curvature of the first lens, and facilitating the incidence of large-angle light to the optical system, thus ensuring the imaging quality of the optical system. By satisfying the upper limit of the relational formula, the object side of the first lens can be prevented from being too flat, reducing the risk of ghosting.

[0069] Example 1

[0070] 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.

[0071] 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: 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.

[0072] The first lens E1 has positive optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has negative optical power, with its object-side surface S3 being convex and its image-side surface S4 being concave. The third lens E3 has positive 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 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 concave 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.

[0073] 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).

[0074] Table 1

[0075]

[0076] 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:

[0077]

[0078] 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 that can be used for each aspherical surface in Example 1.

[0079] Table 2

[0080]

[0081] Figure 2 The on-axis chromatic aberration, astigmatism, and distortion curves of the optical imaging lens of Example 1 are shown. On-axis chromatic aberration represents the deviation of the focal point of light of different wavelengths after passing through the lens; astigmatism represents the curvature of the meridional and sagittal image planes; distortion represents the magnitude of distortion at different image heights. The optical imaging lens given in Example 1 can achieve good image quality.

[0082] Example 2

[0083] 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.

[0084] 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: 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.

[0085] The first lens E1 has positive optical power, with its object-side surface S1 being convex and its image-side surface S2 being convex. The second lens E2 has negative optical power, with its object-side surface S3 being concave and its image-side surface S4 being concave. The third lens E3 has positive 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 positive 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.

[0086] 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).

[0087] Table 3

[0088]

[0089] 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:

[0090]

[0091] 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, and r max The maximum value of the radial radius coordinate is u = r / r max Table 4 provides the conic coefficients and higher-order 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 Example 2.

[0092] Table 4

[0093]

[0094] Figure 4 The on-axis chromatic aberration, astigmatism, and distortion curves of the optical imaging lens of Example 2 are shown. On-axis chromatic aberration represents the deviation of the focal point of light of different wavelengths after passing through the lens; astigmatism represents the curvature of the meridional and sagittal image planes; distortion represents the magnitude of distortion at different image heights. The optical imaging lens given in Example 2 can achieve good image quality.

[0095] Example 3

[0096] 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.

[0097] 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: 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.

[0098] The first lens E1 has positive optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has negative optical power, with its object-side surface S3 being convex and its image-side surface S4 being concave. The third lens E3 has positive 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 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 concave 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.

[0099] 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).

[0100] Table 5

[0101]

[0102] 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:

[0103]

[0104] 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, and r max The maximum value of the radial radius coordinate is u = r / r max Table 6 provides the conic coefficients and higher-order 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 Example 3.

[0105] Table 6

[0106]

[0107] Figure 6The on-axis chromatic aberration, astigmatism, and distortion curves of the optical imaging lens of Example 3 are shown. On-axis chromatic aberration represents the deviation of the focal point of light of different wavelengths after passing through the lens; astigmatism represents the curvature of the meridional and sagittal image planes; distortion represents the magnitude of distortion at different image heights. The optical imaging lens given in Example 3 can achieve good image quality.

[0108] Example 4

[0109] 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.

[0110] 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: 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.

[0111] The first lens E1 has positive optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has negative optical power, with its object-side surface S3 being convex and its image-side surface S4 being concave. The third lens E3 has positive 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 convex and its image-side surface S8 being concave. 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 positive 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.

[0112] 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).

[0113] Table 7

[0114]

[0115] 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:

[0116]

[0117] 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, and r max The maximum value of the radial radius coordinate is u = r / r max Table 8 provides the conic coefficients and higher-order 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 Example 4.

[0118] Table 8

[0119]

[0120] Figure 8 The on-axis chromatic aberration, astigmatism, and distortion curves of the optical imaging lens of Example 4 are shown. On-axis chromatic aberration represents the deviation of the focal point of light of different wavelengths after passing through the lens; astigmatism represents the curvature of the meridional and sagittal image planes; distortion represents the magnitude of distortion at different image heights. The optical imaging lens given in Example 4 can achieve good image quality.

[0121] In Examples 1-4, the basic data is as follows:

[0122] Table 9

[0123]

[0124] In Examples 1-4, each conditional expression satisfies the conditions in the table below:

[0125] Table 10

[0126]

[0127] A camera module includes at least an optical lens, in which the aforementioned telephoto imaging optical system is installed. It features telephoto capability, small overall size, low cost, 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 image quality.

[0128] 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 telephoto imaging optical system, characterized in that: Along the optical axis from the object plane to the image plane, it consists of an aperture stop, 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 is convex. The second lens has negative optical power, and its image-side surface is concave. The third lens has positive optical power, and its object side is convex while its image side is concave. The fourth lens has positive optical power; The fifth lens has optical power, and its object side is convex and its image side 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; 7.5 < f / (T23+T56) < 11; Where 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 and fifth lenses, f is the effective focal length of the optical imaging system, T23 is the air gap between the second and third lenses on the optical axis, and T56 is the air gap between the fifth and sixth lenses on the optical axis.

2. 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 / ImgH < 3.4° / mm; Where 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.

3. The telephoto imaging optical system according to any one of claims 1-2, characterized in that: The telephoto imaging optical system satisfies the following relationship: 0 < |R8| / R2 < 2.4; 0.4 < |(R11+R12) / R11| < 2.1; Wherein, R2 is the radius of curvature of the image side of the first lens, R8 is the radius of curvature of the image side of the fourth lens, R11 is the radius of curvature of the object side of the sixth lens, and R12 is the radius of curvature of the image side of the sixth lens.

4. The telephoto imaging optical system according to any one of claims 1-2, characterized in that: The telephoto imaging optical system satisfies the following relationship: 14mm < (FNO*f*ImgH) / TTL < 16mm; 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 the diagonal length of the effective pixel area on the imaging surface, and TTL is the on-axis distance from the object side of the first lens to the imaging surface.

5. The telephoto imaging optical system according to any one of claims 1-2, 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; Wherein, 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.

6. The telephoto imaging optical system according to any one of claims 1-2, characterized in that: The telephoto imaging optical system satisfies the following relationship: 3.5 < DT31 / SAG5 < 4.2; Wherein, DT31 is half of the maximum effective light-transmitting aperture of the side surface of the third lens, and SAG5 is the distance from the maximum effective light-transmitting aperture of the side surface of the third lens to the intersection of the side surface of the first lens and the optical axis in the direction parallel to the optical axis.

7. The telephoto imaging optical system according to claim 1, characterized in that: The F-number of the telephoto imaging optical system ranges from 2.00 to 2.20, and the overall length ranges from 16.30 to 19.00 mm.

8. 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.

9. 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 1-8.

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