Low-distortion high-pixel optical system and camera module using the same

Abstract

The application provides a low-distortion high-pixel optical system and an applied camera module, which are mainly composed of eight lenses, wherein the first lens has a convex object plane, a concave image plane and negative optical power; the second lens has a convex object plane, a concave image plane and negative optical power; the third lens has a concave object plane, a convex image plane and positive optical power; the fourth lens has a convex object plane and positive optical power; the fifth lens has a convex object plane, a convex image plane and positive optical power; the sixth lens has a concave object plane, a concave image plane and negative optical power; the seventh lens has a convex image plane and positive optical power; and the eighth lens has a convex object plane, a concave image plane and negative optical power. The application has reasonable lens number, simple structure, optimized lens aberration, improved resolution performance, wide angle, small distortion and high resolution, and is applied to a video conference equipment in a video transmission technology, so that image noise can be reduced, good imaging quality can be realized, and post-processing algorithm is facilitated.

Description

Technical Field

[0001] This application relates to the field of optical imaging, and more particularly to a low-distortion, high-pixel optical system and its application in camera modules. Background Technology

[0002] With technological advancements and the needs of socio-economic development, video transmission technology has developed rapidly, leading to the emergence of video conferencing equipment utilizing this technology. Currently, existing video transmission lenses typically have only around two million pixels, resulting in high image noise, poor image quality, and difficulties in post-processing algorithms. Therefore, providing a high-quality optical system has become a key objective. Summary of the Invention

[0003] To overcome the problems of high image noise and poor imaging quality that are commonly found in existing optical systems or camera lenses used in video transmission lenses, this application provides a low-distortion, high-pixel optical system that has the advantages of wide angle, low distortion, and high resolution.

[0004] To achieve its objectives, the present invention employs the following technical solution:

[0005] A low-distortion, high-pixel optical system comprises, along the optical axis from the object plane to the image plane, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens.

[0006] The object plane side of the first lens is convex, and the image plane side is concave, and its optical power is negative.

[0007] The object side of the second lens is convex, and the image side is concave, and its optical power is negative.

[0008] The object plane side of the third lens is concave, the image plane side is convex, and its optical power is positive.

[0009] The object plane of the fourth lens is convex, and its optical power is positive.

[0010] The fifth lens has a convex object plane and a convex image plane, and its optical power is positive.

[0011] The object plane side of the sixth lens is concave, the image plane side is concave, and its optical power is negative.

[0012] The image plane side of the seventh lens is convex, and its optical power is positive.

[0013] The object side of the eighth lens is convex, and the image side is concave, with a negative optical power.

[0014] Furthermore, each lens in this optical system satisfies the following condition:

[0015] -30mm < f1 < -23mm;

[0016] -23mm < f2 < -18mm;

[0017] 45mm < f3 < 1056mm;

[0018] 10mm < f4 < 13mm;

[0019] 6mm < f5 < 6.3mm;

[0020] -9mm < f6 < -7.5mm;

[0021] 11mm < f7 < 33mm;

[0022] -36mm < f8 < -9mm;

[0023] Where f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, f7 is the focal length of the seventh lens, and f8 is the focal length of the eighth lens.

[0024] Furthermore, each lens in this optical system satisfies the following condition:

[0025] -9 < f1 / f < -6;

[0026] -7 < f2 / f < -5;

[0027] 13 < f3 / f < 306;

[0028] 2 < f4 / f < 4;

[0029] 1 < f5 / f < 2;

[0030] -3 < f6 / f < -2;

[0031] 3 < f7 / f < 10;

[0032] -11 < f8 / f < -2;

[0033] Where f is the focal length of the entire optical system, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, f7 is the focal length of the seventh lens, and f8 is the focal length of the eighth lens.

[0034] Furthermore, the refractive index Nd1 and Abbe constant Vd1 of the first lens satisfy: 1.69 < Nd1 < 1.8, 53 < Vd1 < 56;

[0035] The refractive index Nd2 and Abbe number Vd2 of the material of the second lens satisfy: 1.53 < Nd2 < 1.54, 55 < Vd2 < 56;

[0036] The refractive index Nd3 and Abbe number Vd3 of the material of the third lens satisfy the following conditions: 1.53 < Nd3 < 1.54, 55 < Vd3 < 56;

[0037] The refractive index Nd4 and Abbe number Vd4 of the material of the fourth lens satisfy: 1.61 < Nd4 < 1.62, 63 < Vd4 < 64;

[0038] The refractive index Nd5 and Abbe number Vd5 of the material of the fifth lens satisfy: 1.53 < Nd5 < 1.54, 55 < Vd5 < 56;

[0039] The refractive index Nd6 and Abbe number Vd6 of the material of the sixth lens satisfy: 1.66 < Nd6 < 1.67, 20 < Vd6 < 21;

[0040] The refractive index Nd7 and Abbe number Vd7 of the seventh lens satisfy the following conditions: 1.49 < Nd7 < 1.6, 55 < Vd7 < 82;

[0041] The refractive index Nd8 and Abbe number Vd8 of the material of the eighth lens satisfy the following conditions: 1.66 < Nd8 < 1.67, 20.36 < Vd8 < 20.37.

[0042] Furthermore, the learning system satisfies the following relationship:

[0043] 0.73 < f / TTL*ImagH < 0.75;

[0044] Where f is the effective focal length of the optical system, TTL is the on-axis distance from the object side of the first lens to the imaging plane, and ImgH is half the diagonal length of the effective pixel area on the imaging plane.

[0045] Furthermore, the first and fourth lenses are spherical lenses, while the second, third, fifth, sixth, seventh, and eighth lenses are aspherical lenses.

[0046] Furthermore, the field of view (FOV) of this optical system satisfies: 122° < FOV < 125°, and the F-number of the optical system is 2.4.

[0047] Furthermore, the system aperture is positioned between the fourth and fifth lenses.

[0048] On the other hand, embodiments of this application also provide a camera module, which includes at least an optical lens, wherein the aforementioned low-distortion high-pixel optical system is installed within the optical lens.

[0049] Compared with the prior art, the beneficial effects of this application are as follows:

[0050] This invention provides a low-distortion, high-pixel optical system and its application in a camera module, which mainly consists of 8 lenses. The number of lenses is reasonable and the structure is simple. By rationally allocating the optical power of the lenses, the lens aberration is optimized and the resolution performance is improved. It has the advantages of wide angle, low distortion, and high resolution. When applied to video conferencing equipment in video transmission technology, it can reduce image noise, achieve good imaging quality, and facilitate post-processing algorithms. Attached Figure Description

[0051] 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.

[0052] Figure 1 This is a schematic diagram of the structure of the optical system or camera lens in Embodiment 1 of this application;

[0053] Figure 2 This is a distortion curve diagram of the optical system or camera lens in Embodiment 1 of this application;

[0054] Figure 3 This is an MTF curve of the optical system or camera lens of Embodiment 1 of this application;

[0055] Figure 4 This is a schematic diagram of the structure of the optical system or camera lens in Embodiment 2 of this application;

[0056] Figure 5 This is a distortion curve diagram of the optical system or camera lens in Embodiment 2 of this application;

[0057] Figure 6 This is the MTF curve of the optical system or camera lens in Embodiment 2 of this application;

[0058] Figure 7 This is a schematic diagram of the structure of the optical system or camera lens in Embodiment 3 of this application;

[0059] Figure 8 This is a distortion curve diagram of the optical system or camera lens in Embodiment 3 of this application;

[0060] Figure 9 This is the MTF curve of the optical system or camera module in Embodiment 3 of this application. Detailed Implementation

[0061] This application provides a low-distortion, high-pixel optical system comprising a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, an aperture stop STO, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, and a filter E9 arranged sequentially from the object side along the optical axis.

[0062] The object plane side of the first lens E1 is convex, and the image plane side is concave, and its optical power is negative.

[0063] The object side of the second lens E2 is convex, and the image side is concave, and its optical power is negative.

[0064] The object plane side of the third lens E3 is concave, and the image plane side is convex, and its optical power is positive.

[0065] The object side of the fourth lens E4 is convex, and its optical power is positive.

[0066] The fifth lens E5 has a convex object plane and a convex image plane, and its optical power is positive.

[0067] The object plane side of the sixth lens E6 is concave, the image plane side is concave, and its optical power is negative.

[0068] The image plane side of the seventh lens E7 is convex, and its optical power is positive.

[0069] The object plane side of the eighth lens E8 is convex, the image plane side is convex, and its optical power is negative.

[0070] The first lens E1 and the fourth lens E4 are spherical lenses, while the second lens E2, the third lens E3, the sixth lens E6, the seventh lens E7, and the eighth lens E8 are aspherical lenses.

[0071] This invention provides a low-distortion, high-pixel optical system, mainly composed of eight lenses. The number of lenses is reasonable and the structure is simple. By rationally allocating the optical power of the lenses, lens aberrations are optimized and resolution performance is improved. It has the advantages of wide angle, low distortion, and high resolution. When applied to video conferencing equipment in video transmission technology, it can reduce image noise, achieve good imaging quality, and facilitate subsequent algorithm processing.

[0072] Preferably, each lens of the optical system satisfies the following conditions: (1) -30mm < f1 < -23mm; (2) -23mm < f2 < -18mm; (3) 45mm < f3 < 1056mm; (4) 10mm < f4 < 13mm; (5) 6mm < f5 < 6.3mm; (6) -9mm < f6 < -7.5mm; (7) 12mm < f7 < 33mm; (8) -36mm < f8 < -9mm; where f1 is the focal length of the first lens E1. f2 is the focal length of the second lens E2, f3 is the focal length of the third lens E3, f4 is the focal length of the fourth lens E4, f5 is the focal length of the fifth lens E5, f6 is the focal length of the sixth lens E6, f7 is the focal length of the seventh lens E7, and f8 is the focal length of the eighth lens E8. By rationally allocating the focal lengths of each lens, the imaging quality of the system is effectively improved, featuring wide-angle and low-distortion characteristics, while also possessing the advantage of high angular resolution. This reduces image noise, achieves good imaging quality, and is beneficial for subsequent algorithm processing.

[0073] Preferably, each lens of the optical system satisfies the following condition:

[0074] (1) -9 < f1 / f < -6, by constraining the effective focal length ratio of the first lens E1 to the optical system within a reasonable range, the distortion of the system is controlled, so that the imaging center has a higher angular resolution;

[0075] (2) -7 < f2 / f < -5. By constraining the effective focal length ratio of the second lens E2 to the optical imaging system within a reasonable range, the configured optical system has excellent temperature characteristics, thereby improving the stability of the optical system imaging at high and low temperatures and improving the imaging quality.

[0076] (3) 13 < f3 / f < 306. By constraining the effective focal length ratio of the third lens E3 to the optical imaging system within a reasonable range, the spherical aberration of the system can be finely adjusted and controlled, thereby effectively improving the imaging quality of the system.

[0077] (4) 2 < f4 / f < 4. By reasonably controlling the effective focal length ratio range of the fourth lens E4 and the optical imaging system, the astigmatism and field curvature of the system are well corrected, and the imaging quality of the system is effectively improved.

[0078] (5) 1 < f5 / f < 2. By constraining the ratio of the optical power of the fifth lens E5 to the effective focal length of the optical imaging system within a reasonable range, the configured optical system has excellent temperature characteristics, thereby improving the stability of the optical system imaging at high and low temperatures and improving the imaging quality.

[0079] (6) -3 < f6 / f < -2, by constraining the effective focal length ratio of the sixth lens E6 to the optical imaging system within a reasonable range, the lens aberration is optimized and the resolution performance is improved;

[0080] (7) 3 < f7 / f < 10. By constraining the effective focal length ratio of the seventh lens E7 to the optical imaging system within a reasonable range, good optical performance can be guaranteed, lens aberrations can be optimized, resolution performance can be improved, and the viewing angle can be further guaranteed.

[0081] (8) -11 < f8 / f < -2. By constraining the effective focal length ratio of the eighth lens E8 to the optical imaging system within a reasonable range, the internal aberrations of the optical lens can be balanced, which in turn helps to adjust the field curvature and astigmatism at the imaging edge of the optical lens and meet the imaging quality of the optical lens for the surrounding environment.

[0082] Where f is the focal length of the entire optical system, f1 is the focal length of the first lens E1, f2 is the focal length of the second lens E2, f3 is the focal length of the third lens E3, f4 is the focal length of the fourth lens E4, f5 is the focal length of the fifth lens E5, f6 is the focal length of the sixth lens E6, f7 is the focal length of the seventh lens E7, and f8 is the focal length of the eighth lens E8.

[0083] Preferably, the refractive index Nd1 and Abbe constant Vd1 of the material of the first lens E1 satisfy: 1.69 < Nd1 < 1.8, 53 < Vd1 < 56. This design can effectively reduce chromatic aberration, optimize lens aberration, and thus effectively improve the imaging quality of the system.

[0084] Preferably, the refractive index Nd2 and Abbe number Vd2 of the material of the second lens E2 satisfy: 1.53 < Nd2 < 1.54, 55 < Vd2 < 56, which can ensure good optical performance, further guarantee the viewing angle, improve the lens resolution and reduce distortion.

[0085] Preferably, the refractive index Nd3 and Abbe number Vd3 of the material of the third lens E3 satisfy: 1.53 < Nd3 < 1.54, 55 < Vd3 < 56. This design can effectively reduce chromatic aberration, optimize lens aberration, and thus effectively improve the imaging quality of the system.

[0086] Preferably, the refractive index Nd4 and Abbe number Vd4 of the material of the fourth lens E4 satisfy: 1.61 < Nd4 < 1.62, 63 < Vd4 < 64, which can ensure good optical performance, further guarantee the viewing angle, improve the lens resolution and reduce distortion.

[0087] Preferably, the refractive index Nd5 and Abbe number Vd5 of the fifth lens E5 satisfy: 1.53 < Nd5 < 1.54, 55 < Vd5 < 56. This design can effectively reduce chromatic aberration, optimize lens aberration, and thus effectively improve the imaging quality of the system.

[0088] Preferably, the refractive index Nd6 and Abbe number Vd6 of the material of the sixth lens E6 satisfy: 1.66 < Nd6 < 1.67, 20 < Vd6 < 21. This design can effectively reduce chromatic aberration, optimize lens aberration, and thus effectively improve the imaging quality of the system.

[0089] Preferably, the refractive index Nd7 and Abbe number Vd7 of the seventh lens E7 satisfy: 1.49 < Nd7 < 1.6, 55 < Vd7 < 82, which can ensure good optical performance, further guarantee the viewing angle, improve the lens resolution and reduce distortion.

[0090] Preferably, the refractive index Nd8 and Abbe number Vd8 of the material of the eighth lens E8 satisfy: 1.66 < Nd8 < 1.67, 20.36 < Vd8 < 20.37, which can ensure good optical performance, further guarantee the viewing angle, improve the lens resolution and reduce distortion.

[0091] Preferably, the optical system satisfies the following relationship: 0.73 < f / TTL*ImagH < 0.75; where f is the effective focal length of the optical system, TTL is the axial distance from the object side of the first lens E1 to the imaging plane, and ImgH is half the diagonal length of the effective pixel area on the imaging plane. This relationship reflects the constraints of the optical lens in terms of field of view and thinness. When the above relationship is satisfied, the market demand for small head and thinness of the optical lens can be met while ensuring a wide field of view. When the upper limit of the relationship is exceeded, further reducing f / TTL*ImagH while ensuring a wide field of view will excessively compress the thinness of the optical lens, which is not conducive to improving the performance of the optical lens. When the relationship is lower than the lower limit, the thinness of the optical lens is insufficient, which is not conducive to the miniaturization design of the optical lens.

[0092] Preferably, the field of view (FOV) of the optical system satisfies: 122° < FOV < 125°, and the F-number of the optical system is 2.4. This design can effectively miniaturize the lens. The optical system configured in this invention has the advantage of wide angle, compact structure, easy processing and installation, increases the light intake of the optical system and higher imaging quality. Through reasonable allocation of optical power and optimization of high-order aspherical parameters, it can achieve low distortion while taking into account high resolution and wide-angle shooting functions.

[0093] Specifically, as a preferred embodiment of the present invention and not a limitation thereof, reference is made to... Figures 1 to 3 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, as follows: Figure 1As shown, 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 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 concave and its image-side surface S6 being convex. 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 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 concave and its image-side surface S12 being concave. The seventh lens E7 has positive optical power, with its object-side surface S13 being concave and its image-side surface S14 being convex. The eighth lens E8 has negative optical power, with its object-side surface S15 being convex and its image-side surface S16 being concave. The filter E9 has an object-side surface S17 and an image-side surface S18. Light from the object passes sequentially through each surface S1 to S18 and is finally imaged onto the imaging surface S19.

[0094] Table 1 shows the surface type, radius of curvature, thickness, and material of each lens in the optical imaging lens of Example 1, where the units for radius of curvature and thickness are millimeters (mm):

[0095] Table 1: Basic parameters of the optical system in Example 1

[0096]

[0097] In Table 1 above, the object-side surface and image-side surface of any one of the following lenses—E2, E3, E5, to E8—are aspherical. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formulas:

[0098]

[0099] Where x is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, h is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the vertex of the aspherical surface, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th higher-order term in the aspherical surface shape formula. Table 2 gives the conic coefficients and higher-order coefficients A4, A6, A8, A10, A12, A14, and A16 that can be used for each aspherical surface in Example 1.

[0100] Table 2: Aspherical correlation values ​​of the lens surface in Example 1

[0101]

[0102] Figure 2 The astigmatism and distortion curves of the optical imaging lens of Example 1 are shown. Astigmatism represents the meridional image plane curvature and the sagittal image plane curvature; distortion represents the distortion magnitude corresponding to different image heights.

[0103] Figure 3 The MTF curve of the optical imaging lens of Example 1 is shown, which represents the MTF values ​​in the meridional and sagittal directions of different fields of view.

[0104] Depend on Figure 2 and Figure 3 It can be seen that the optical lens given in Example 1 can achieve good imaging quality.

[0105] Specifically, this is a preferred embodiment of the invention and not a limitation thereof. Figure 4 A schematic diagram of the structure of an optical imaging lens according to Embodiment 2 of this application is shown, as follows: Figure 4 As shown, 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 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 concave and its image-side surface S6 being convex. 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 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 concave and its image-side surface S12 being concave. The seventh lens E7 has positive optical power, with its object-side surface S13 being convex and its image-side surface S14 being convex. The eighth lens E8 has negative optical power, with its object-side surface S15 being convex and its image-side surface S16 being concave. The filter E9 has an object-side surface S17 and an image-side surface S18. Light from the object passes sequentially through each surface S1 to S18 and is finally imaged onto the imaging surface S19.

[0106] Table 3 shows the surface type, radius of curvature, thickness, and material of each lens in the optical imaging lens of Example 2, where the units for radius of curvature and thickness are millimeters (mm):

[0107] Table 3: Basic parameters of the optical system in Example 2

[0108]

[0109] In Table 3 above, the object-side surface and image-side surface of any one of the following lenses—E2 (second lens), E3 (third lens), E6 (sixth lens), to E8 (eighth lens)—are aspherical. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formulas:

[0110]

[0111] Where x is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, h is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the vertex of the aspherical surface, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th higher-order term in the aspherical surface shape formula. Table 4 gives the conic coefficients and higher-order term coefficients A4, A6, A8, A10, A12, A14, and A16 that can be used for each aspherical surface in Example 2.

[0112] Table 4: Aspherical correlation values ​​of the lens surface in Example 2

[0113]

[0114] Figure 5 The astigmatism and distortion curves of the optical imaging lens of Example 2 are shown. Astigmatism represents the meridional image plane curvature and the sagittal image plane curvature; distortion represents the distortion magnitude corresponding to different image heights.

[0115] Figure 6 The MTF curve of the optical imaging lens of Example 2 is shown, which represents the MTF values ​​in the meridional and sagittal directions of different fields of view.

[0116] Depend on Figure 5 and Figure 6 It can be seen that the optical imaging lens given in Example 2 can achieve good imaging quality.

[0117] Specifically, this is a preferred embodiment of the invention and not a limitation thereof. Figure 7 A schematic diagram of the structure of an optical imaging lens according to Embodiment 3 of this application is shown, as follows: Figure 7 As shown, 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 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 concave and its image-side surface S6 being convex. 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 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 concave and its image-side surface S12 being concave. The seventh lens E7 has positive optical power, with its object-side surface S13 being convex and its image-side surface S14 being convex. The eighth lens E8 has negative optical power, with its object-side surface S15 being convex and its image-side surface S16 being concave. The filter E9 has an object-side surface S17 and an image-side surface S18. Light from the object passes sequentially through each surface S1 to S18 and is finally imaged onto the imaging surface S19.

[0118] 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).

[0119] Table 5: Basic parameters of the optical system in Example 3

[0120]

[0121] In Table 5 above, the object-side surface and image-side surface of any one of the following lenses—E2 (second lens), E3 (third lens), E6 (sixth lens), to E8 (eighth lens)—are aspherical. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formulas:

[0122]

[0123] Where x is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, h is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the vertex of the aspherical surface, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th higher-order term in the aspherical surface shape formula. Table 6 gives the conic coefficients and higher-order coefficients A4, A6, A8, A10, A12, A14, and A16 for each aspherical surface that can be used in the first embodiment.

[0124] Table 6: Aspherical Correlation Values ​​of Lens Surface in Example 3

[0125]

[0126] Figure 8 The astigmatism and distortion curves of the optical imaging lens of Example 3 are shown. Astigmatism represents the meridional image plane curvature and the sagittal image plane curvature; distortion represents the distortion magnitude corresponding to different image heights.

[0127] Figure 9 The MTF curve of the optical imaging lens of Example 3 is shown, which represents the MTF values ​​in the meridional and sagittal directions of different fields of view.

[0128] Depend on Figure 8 and Figure 9 It can be seen that the optical imaging lens given in Example 3 can achieve good imaging quality.

[0129] Furthermore, in Examples 1-3, the basic data is as follows:

[0130] Table 7: Basic Data for Examples 1-3

[0131]

[0132] A camera module includes at least an optical lens, within which the aforementioned low-distortion, high-resolution optical system is installed. This invention discloses a low-distortion, high-resolution optical system and its application in a camera module. It mainly consists of eight lenses, with a reasonable number of lenses and a simple structure. By rationally allocating the lens power, lens aberrations are optimized, and resolution performance is improved. It possesses advantages such as wide-angle, low distortion, and high resolution. When applied to video conferencing equipment using video transmission technology, it can reduce image noise, achieve good imaging quality, and facilitate subsequent algorithm processing.

[0133] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A low-distortion, high-pixel optical system, comprising, sequentially from the object plane to the image plane along the optical axis, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens, characterized in that: The object plane side of the first lens is convex, and the image plane side is concave, and its optical power is negative. The object side of the second lens is convex, and the image side is concave, and its optical power is negative. The object plane side of the third lens is concave, the image plane side is convex, and its optical power is positive. The object plane of the fourth lens is convex, and its optical power is positive. The fifth lens has a convex object plane and a convex image plane, and its optical power is positive. The object plane side of the sixth lens is concave, the image plane side is concave, and its optical power is negative. The image plane side of the seventh lens is convex, and its optical power is positive. The object side of the eighth lens is convex, and the image side is concave, and its optical power is negative. The first and fourth lenses are spherical lenses, and the system aperture is located between the fourth and fifth lenses; Each lens in this optical system satisfies the following condition: -30mm < f1 < -23mm; -23mm < f2 < -18mm; 45mm < f3 < 1056mm; 10mm < f4 < 13mm; 6mm < f5 < 6.3mm; -9mm < f6 < -7.5mm; 11mm < f7 < 33mm; -36mm < f8 < -9mm; Where f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, f7 is the focal length of the seventh lens, and f8 is the focal length of the eighth lens.

2. The low-distortion, high-pixel optical system according to claim 1, characterized in that: Each lens in this optical system satisfies the following condition: -9 < f1 / f < -6; -7 < f2 / f < -5; 13 < f3 / f < 306; 2 < f4 / f < 4; 1 < f5 / f < 2; -3 < f6 / f < -2; 3 < f7 / f < 10; -11 < f8 / f < -2; Where f is the focal length of the entire optical system, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, f7 is the focal length of the seventh lens, and f8 is the focal length of the eighth lens.

3. The low-distortion, high-pixel optical system according to claim 1, characterized in that: The refractive index Nd1 and Abbe constant Vd1 of the material of the first lens satisfy: 1.69 < Nd1 < 1.8, 53 < Vd1 < 56; The refractive index Nd2 and Abbe number Vd2 of the material of the second lens satisfy: 1.53 < Nd2 < 1.54, 55 < Vd2 < 56; The refractive index Nd3 and Abbe number Vd3 of the material of the third lens satisfy the following conditions: 1.53 < Nd3 < 1.54, 55 < Vd3 < 56; The refractive index Nd4 and Abbe number Vd4 of the material of the fourth lens satisfy: 1.61 < Nd4 < 1.62, 63 < Vd4 < 64; The refractive index Nd5 and Abbe number Vd5 of the material of the fifth lens satisfy: 1.53 < Nd5 < 1.54, 55 < Vd5 < 56; The refractive index Nd6 and Abbe number Vd6 of the material of the sixth lens satisfy: 1.66 < Nd6 < 1.67, 20 < Vd6 < 21; The refractive index Nd7 and Abbe number Vd7 of the seventh lens satisfy the following conditions: 1.49 < Nd7 < 1.6, 55 < Vd7 < 82; The refractive index Nd8 and Abbe number Vd8 of the material of the eighth lens satisfy the following conditions: 1.66 < Nd8 < 1.67, 20.36 < Vd8 < 20.

37.

4. The low-distortion, high-pixel optical system according to any one of claims 1-3, characterized in that: The learning system satisfies the following relationship: 0.73mm < f / TTL*ImagH < 0.75mm; Where f is the effective focal length of the optical system, TTL is the on-axis distance from the object side of the first lens to the imaging plane, and ImgH is half the diagonal length of the effective pixel area on the imaging plane.

5. The low-distortion, high-pixel optical system according to any one of claims 1-3, characterized in that: The second, third, fifth, sixth, seventh, and eighth lenses are aspherical lenses.

6. The low-distortion, high-pixel optical system according to any one of claims 1-3, characterized in that: The field of view (FOV) of this optical system satisfies the following condition: 122° < FOV < 125°.

7. The low-distortion, high-pixel optical system according to any one of claims 1-3, characterized in that: The F-number of this optical system is 2.

4.

8. A camera module, comprising at least an optical lens, characterized in that: The optical lens is equipped with the low-distortion, high-pixel optical system according to any one of claims 1-7.

Images