Optical systems, camera modules and terminal equipment

Abstract

The embodiments of the present application disclose an optical system, a camera module and a terminal device. The optical system includes a first lens and a fifth lens with positive refractive power, a second lens and a seventh lens with negative refractive power, a third lens, a fourth lens and a sixth lens with refractive power, the object side surface of the first lens is convex at the near optical axis, the image side surface of the fourth lens is concave at the near optical axis, the object side surface and the image side surface of the fifth lens are both convex at the near optical axis, the image side surface of the sixth lens is convex at the near optical axis, and the image side surface of the seventh lens is concave at the near optical axis; the image side surface of the first lens and the object side surface of the second lens are glued together. The present application reasonably configures the refractive power and surface shape of the first lens to the seventh lens in the optical system and limits the gluing of the first lens and the second lens, so that the optical system can achieve the characteristics of miniaturization and small head and improve the molding yield of the lens.

Description

Technical Field

[0001] The present application belongs to the field of optical imaging technology, and in particular, relates to an optical system, a camera module and a terminal device. Background Art

[0002] In recent years, with the rapid development of manufacturing technology for electronic products such as smartphones, tablets, and cameras and the emergence of increasingly diversified user needs, the market's requirements for optical system specifications have become increasingly higher.

[0003] At present, the size of the optical system tends to be miniaturized and thinner under the market trend, but the head of the optical system is large, which is not conducive to the under-screen packaging of the optical system, and the screen opening is large. In addition, the thickness ratio of the lens is usually large, which makes it difficult to shape the lens.

[0004] Therefore, how to improve the molding yield of the lens and realize the miniaturization of the optical system and the characteristics of a small head should be the research and development direction of the industry. Summary of the invention

[0005] The embodiments of the present application provide an optical system, a camera module and a terminal device. The optical system can achieve the characteristics of miniaturization and a small head and improve the molding yield of the lens of the optical system.

[0006] In a first aspect, an embodiment of the present application provides an optical system, which includes a plurality of lenses, wherein the plurality of lenses include a first lens arranged in sequence from an object side (the object side refers to the side where light is incident) to an image side (the image side refers to the side where light is emitted), and having a positive refractive power, wherein the object side surface of the first lens is convex at the near optical axis; a second lens having a negative refractive power; a third lens having a refractive power; a fourth lens having a refractive power, wherein the image side surface of the fourth lens is concave at the near optical axis; a fifth lens having a positive refractive power, wherein both the object side surface and the image side surface of the fifth lens are convex at the near optical axis; a sixth lens having a refractive power, wherein the image side surface of the sixth lens is convex at the near optical axis; a seventh lens having a negative refractive power, wherein the image side surface of the seventh lens is concave at the near optical axis; and the image side surface of the first lens and the object side surface of the second lens are glued together.

[0007] Among them, the refractive power is the focal length, which represents the ability of the optical system to deflect light. Positive refractive power means that the lens converges the light beam, and negative refractive power means that the lens diverges the light beam. When the lens has no refractive power, that is, when the focal length is zero, it is a plane refraction. At this time, the parallel light beam along the axis is still a parallel light beam along the axis after refraction, and no refraction occurs.

[0008] The present application reasonably configures the refractive power of the first to seventh lenses in the optical system and the surface shapes of the first lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens and limits the bonding of the first lens and the second lens, so that the optical system has the characteristics of miniaturization and small head and improves the molding yield of the lenses of the optical system. The present application reduces the thickness ratio of the lens by setting the bonding of the first lens and the second lens, improves the molding yield, and reduces the possibility of the generation of weld lines.

[0009] In other embodiments, the optical system includes a plurality of lenses, wherein the plurality of lenses include a first lens arranged in sequence from the object side (the object side refers to the side where light is incident) to the image side (the image side refers to the side where light is emitted), having a positive refractive power, the object side surface of the first lens is convex at near the optical axis, and the object side surface and the image side surface of the first lens are both convex at the circumference; a second lens having a negative refractive power, the object side surface of the second lens is concave at the circumference, and the image side surface of the second lens is convex at the circumference; a third lens having a refractive power; a fourth lens having a refractive power, and the image side surface of the fourth lens is at near the optical axis. is concave; a fifth lens having positive refractive power, the object side surface and the image side surface of the fifth lens are both convex at the near optical axis, the object side surface of the fifth lens is concave at the circumference, and the image side surface of the fifth lens is convex at the circumference; a sixth lens having refractive power, the object side surface of the sixth lens is concave at the circumference, and the image side surface of the sixth lens is convex at the near optical axis and at the circumference; a seventh lens having negative refractive power, the image side surface of the seventh lens is concave at the near optical axis, and the image side surface of the seventh lens is convex at the circumference; the image side surface of the first lens and the object side surface of the second lens are glued together.

[0010] It should be noted that, compared with the aforementioned embodiment, the present embodiment limits the surface shape of the lens at the circumference, which can enhance the performance of the optical system of the present application and improve the molding yield of the lens. Specifically, the object side surface and the image side surface of the first lens are convex at the circumference, which can make the first lens have an appropriate thickness, reduce the thickness ratio of the first lens, reduce the molding and manufacturing difficulty of the first lens, and help improve the optical convergence ability of the first lens; the object side surface of the second lens is a concave surface at the circumference and the image side surface of the second lens is a convex surface at the circumference, which can effectively focus light, and the first lens The image side surface is convex at the circumference and the object side surface of the second lens is concave at the circumference, which is conducive to the bonding of the first lens and the second lens, so as to reduce the thickness ratio of the lens, improve the molding yield, and reduce the possibility of the weld line; the object side surface of the fifth lens is concave at the circumference, and the image side surface of the fifth lens is convex at the circumference, which is conducive to the miniaturization of the optical system; the object side surface of the sixth lens is concave at the circumference, and the image side surface of the sixth lens is convex at the circumference, which is conducive to correcting aberrations; the image side surface of the seventh lens is convex at the circumference, which effectively corrects the distortion and aberrations generated by the first lens to the sixth lens.

[0011] In one embodiment, the optical system satisfies the conditional formula: (CT1+CT2) / TTL>0.23, CT1 is the thickness of the first lens on the optical axis, CT2 is the thickness of the second lens on the optical axis, and TTL is the distance from the object side of the first lens to the imaging surface on the optical axis in the optical system. The thickness of the lens affects the difficulty of lens molding and manufacturing. When the difference between the middle thickness and the edge thickness of the lens is large, that is, the thickness ratio of the lens is large, and the thickness ratio is greater than 2.5, a weld line will appear during the injection molding process. By limiting the appropriate range of (CT1+CT2) / TTL and limiting the bonding of the first lens and the second lens, the first lens and the second lens can have an appropriate thickness, reduce the lens thickness ratio, reduce the molding and manufacturing difficulty of the first lens and the second lens, improve the molding yield, reduce the possibility of weld lines during injection molding, and enable the bonded lens formed after the first lens and the second lens are bonded to meet the under-screen lens design.

[0012] In one embodiment, the optical system satisfies the conditional formula: SD11 / ImgH<0.28, SD11 is the maximum effective aperture of the object side of the first lens, specifically, SD11 is the vertical distance from the maximum effective aperture of the object side of the first lens to the optical axis, and ImgH is half of the image height corresponding to the maximum field angle of the optical system. By limiting SD11 / ImgH<0.28, the structural characteristics of the small head of the optical system can be ensured, and the screen opening diameter can be reduced when used under the screen. If SD11 / ImgH>0.28, the screen opening will be too large, which is not conducive to increasing the screen-to-body ratio of the screen.

[0013] In one embodiment, the optical system satisfies the condition: FNO / SD11≥0.24mm -1 , FNO is the aperture number of the optical system, SD11 is the maximum effective aperture of the object side of the first lens, specifically, SD11 is the vertical distance from the maximum effective aperture of the object side of the first lens to the optical axis. The aperture of the present application is placed in front, and the entrance pupil diameter is the light entrance of the optical system. By limiting the appropriate range of FNO / SD11, it can be ensured that the optical system can reasonably control the amount of light entering the optical system while meeting the small aperture, thereby reducing the difficulty of the optical system in controlling the light trend and improving the overall imaging performance.

[0014] In one embodiment, the optical system satisfies the conditional formula: 0.7<f / f12<1.2, f is the focal length of the optical system, and f12 is the combined focal length of the first lens and the second lens. The cemented lens formed by the cementation of the first lens and the second lens provides a portion of positive refractive power for the optical system, which is used to adjust the overall refractive power of the optical system, converge the light and smoothly transition to the third lens to the seventh lens; by limiting f / f12<1.2, high-order aberrations caused by excessive refractive power can be avoided, and by limiting f / f12>0.7, it can ensure that a sufficiently large convergence ability is provided, reducing the pressure of the third lens to the seventh lens in processing light.

[0015] In one embodiment, the optical system satisfies the conditional formula: |f6 / R61|<11, f6 is the focal length of the sixth lens, and R61 is the radius of curvature of the object side of the sixth lens at the optical axis. This can avoid excessive bending of the object side of the sixth lens at the optical axis, reduce the difficulty of lens processing, and also avoid excessive refractive power of the sixth lens. The refractive power is evenly distributed in the optical system, which can effectively balance the aberrations generated by the first lens to the fifth lens and improve the resolution.

[0016] In one embodiment, the optical system satisfies the conditional formula: 0.9<|R71-R72| / |R71+R72|<3.5, R71 is the radius of curvature of the object side of the seventh lens at the optical axis, and R72 is the radius of curvature of the image side of the seventh lens at the optical axis. By reasonably limiting the range of |R71-R72| / |R71+R72|, it is helpful to correct the aberrations generated by the optical system at a large aperture, so that the refractive power of the optical system in the direction perpendicular to the optical axis is uniformly configured, and the distortion and aberration generated by the first lens to the sixth lens are effectively corrected, while avoiding excessive bending of the seventh lens, reducing the difficulty of molding and manufacturing the seventh lens.

[0017] In one embodiment, the optical system satisfies the conditional formula: 0.18<∑CT / ∑AT<2.7, ∑CT is the sum of the thicknesses of the first lens to the seventh lens on the optical axis, and ∑AT is the sum of the air spacings between adjacent lenses from the first lens to the seventh lens on the optical axis. By reasonably limiting the range of ∑CT / ∑AT, it is beneficial to reasonably control the distance between lenses and realize a compact structure of the optical system. If ∑CT / ∑AT>2.7, the lenses are arranged too closely, which is not conducive to assembly. If ∑CT / ∑AT<0.18, the spacing between the lenses is too large, which is not conducive to the miniaturization design of the optical system.

[0018] In one embodiment, the optical system satisfies the conditional formula: FNO≤2.3, where FNO is the aperture number of the optical system. The aperture of the present application is placed in front, and the entrance pupil diameter is the light entrance of the optical system. By limiting the appropriate range of FNO, it can be ensured that the optical system has sufficient light intake, and the illumination intensity of a single pixel point is increased, thereby improving the shooting effect in a dark environment. In addition, the increase in aperture will reduce the size of the Airy disk, thereby having a higher resolution limit. By reasonably configuring the refractive power of the lens, the design requirements of high pixels can be met.

[0019] In one embodiment, the optical system satisfies the conditional formula: TTL / ImgH<1.55, TTL is the distance from the object side of the first lens in the optical system to the imaging plane on the optical axis, and ImgH is half of the image height corresponding to the maximum field angle of the optical system. ImgH determines the size of the photosensitive element. The larger the ImgH, the larger the size of the maximum photosensitive element that can be supported. By limiting the appropriate range of TTL / ImgH, the optical system can be matched with a high-pixel photosensitive element; the reduction of TTL compresses the length of the entire optical system, making it easy to achieve ultra-thinness and miniaturization of the optical system. Reasonable configuration of the size and refractive power of the lens is conducive to maintaining the compactness of the optical system structure and to achieving good imaging quality for the optical system.

[0020] In a second aspect, the present application provides a camera module, comprising a photosensitive element and the optical system described in any one of the aforementioned embodiments, wherein the photosensitive element is located on the image side of the optical system.

[0021] In a third aspect, the present application provides a terminal device, comprising the camera module.

[0022] By reasonably configuring the refractive powers of the first to seventh lenses in the optical system and the surface shapes of the first lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens and limiting the bonding of the first lens and the second lens, the optical system has the characteristics of miniaturization and small head and the molding yield of the lenses of the optical system is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the background technology, the drawings required for use in the embodiments of the present application or the background technology will be described below.

[0024] Figure 1 is a schematic structural diagram of an optical system provided in the first embodiment of the present application;

[0025] Figure 2 are the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the first embodiment;

[0026] Figure 3is a schematic structural diagram of an optical system provided in a second embodiment of the present application;

[0027] Figure 4 are the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the second embodiment;

[0028] Figure 5 is a schematic structural diagram of an optical system provided in the third embodiment of the present application;

[0029] Figure 6 are a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the third embodiment;

[0030] Figure 7 is a schematic structural diagram of an optical system provided in a fourth embodiment of the present application;

[0031] Figure 8 are a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the fourth embodiment;

[0032] Fig. 9 is a schematic structural diagram of an optical system provided in a fifth embodiment of the present application;

[0033] Fig.10 are a longitudinal spherical aberration curve, an astigmatism curve, and a distortion curve of the optical system of the fifth embodiment;

[0034] Fig.11 It is a schematic diagram of the optical system provided by the present application applied in a terminal device. DETAILED DESCRIPTION

[0035] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0036] The present application provides an optical system including seven lenses, which are arranged in sequence from the object side to the image side as a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens.

[0037] Specifically, the surface shapes and refractive powers of the seven lenses are as follows:

[0038] The first lens has positive refractive power, and the object side surface of the first lens is convex at the near optical axis; the second lens has negative refractive power; the third lens has refractive power; the fourth lens has refractive power, and the image side surface of the fourth lens is concave at the near optical axis; the fifth lens has positive refractive power, and the object side surface and the image side surface of the fifth lens are both convex at the near optical axis; the sixth lens has refractive power, and the image side surface of the sixth lens is convex at the near optical axis; the seventh lens has negative refractive power, and the image side surface of the seventh lens is concave at the near optical axis; wherein the image side surface of the first lens and the object side surface of the second lens are glued together.

[0039] The present application reasonably configures the refractive power of the first to seventh lenses in the optical system and the surface shapes of the first lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens and limits the bonding of the first lens and the second lens, so that the optical system has the characteristics of miniaturization and small head and improves the molding yield of the lenses of the optical system. The present application reduces the thickness ratio of the lens by setting the bonding of the first lens and the second lens, improves the molding yield, and reduces the possibility of the generation of weld lines.

[0040] Or, specifically, the surface shapes and refractive powers of the seven lenses are as follows:

[0041] The first lens has positive refractive power, the object side surface of the first lens is convex at the near optical axis, and the object side surface and image side surface of the first lens are both convex at the circumference; the second lens has negative refractive power, the object side surface of the second lens is concave at the circumference, and the image side surface of the second lens is convex at the circumference; the third lens has refractive power; the fourth lens has refractive power, and the image side surface of the fourth lens is concave at the near optical axis; the fifth lens has positive refractive power, and the object side surface and image side surface of the fifth lens are concave at the near optical axis. The object side surface of the fifth lens is concave at the circumference, and the image side surface of the fifth lens is convex at the circumference; the sixth lens has a refractive power, the object side surface of the sixth lens is concave at the circumference, and the image side surface of the sixth lens is convex at the near optical axis and at the circumference; the seventh lens has a negative refractive power, the image side surface of the seventh lens is concave at the near optical axis, and the image side surface of the seventh lens is convex at the circumference; wherein the image side surface of the first lens and the object side surface of the second lens are glued together.

[0042] It should be noted that, compared with the aforementioned embodiment, the present embodiment limits the surface shape of the lens at the circumference, which can enhance the performance of the optical system of the present application and improve the molding yield of the lens. Specifically, the object side surface and the image side surface of the first lens are convex at the circumference, which can make the first lens have an appropriate thickness, reduce the thickness ratio of the first lens, reduce the molding and manufacturing difficulty of the first lens, and help improve the optical convergence ability of the first lens; the object side surface of the second lens is a concave surface at the circumference and the image side surface of the second lens is a convex surface at the circumference, which can effectively focus light, and the first lens The image side surface is convex at the circumference and the object side surface of the second lens is concave at the circumference, which is conducive to the bonding of the first lens and the second lens, so as to reduce the thickness ratio of the lens, improve the molding yield, and reduce the possibility of the weld line; the object side surface of the fifth lens is concave at the circumference, and the image side surface of the fifth lens is convex at the circumference, which is conducive to the miniaturization of the optical system; the object side surface of the sixth lens is concave at the circumference, and the image side surface of the sixth lens is convex at the circumference, which is conducive to correcting aberrations; the image side surface of the seventh lens is convex at the circumference, which effectively corrects the distortion and aberrations generated by the first lens to the sixth lens.

[0043] In one embodiment, the optical system satisfies the conditional formula: (CT1+CT2) / TTL>0.23, CT1 is the thickness of the first lens on the optical axis, CT2 is the thickness of the second lens on the optical axis, and TTL is the distance from the object side of the first lens to the imaging surface on the optical axis in the optical system. The thickness of the lens affects the difficulty of lens molding and manufacturing. When the difference between the middle thickness and the edge thickness of the lens is large, that is, the thickness ratio of the lens is large, and the thickness ratio is greater than 2.5, a weld line will appear during the injection molding process. By limiting the appropriate range of (CT1+CT2) / TTL and limiting the bonding of the first lens and the second lens, the first lens and the second lens can have an appropriate thickness, reduce the lens thickness ratio, reduce the molding and manufacturing difficulty of the first lens and the second lens, improve the molding yield, reduce the possibility of weld lines during injection molding, and enable the bonded lens formed after the first lens and the second lens are bonded to meet the under-screen lens design.

[0044] In one embodiment, the optical system satisfies the conditional formula: SD11 / ImgH<0.28, SD11 is the maximum effective aperture of the object side of the first lens, specifically, SD11 is the vertical distance from the maximum effective aperture of the object side of the first lens to the optical axis, and ImgH is half of the image height corresponding to the maximum field angle of the optical system. By limiting SD11 / ImgH<0.28, the structural characteristics of the small head of the optical system can be ensured, and the screen opening diameter can be reduced when used under the screen. If SD11 / ImgH>0.28, the screen opening will be too large, which is not conducive to increasing the screen-to-body ratio of the screen.

[0045] In one embodiment, the optical system satisfies the condition: FNO / SD11≥0.24mm -1 , FNO is the aperture number of the optical system, SD11 is the maximum effective aperture of the object side of the first lens, specifically, SD11 is the vertical distance from the maximum effective aperture of the object side of the first lens to the optical axis. The aperture of the present application is placed in front, and the entrance pupil diameter is the light entrance of the optical system. By limiting the appropriate range of FNO / SD11, it can be ensured that the optical system can reasonably control the amount of light entering the optical system while meeting the small aperture, thereby reducing the difficulty of the optical system in controlling the light trend and improving the overall imaging performance.

[0046] In one embodiment, the optical system satisfies the conditional formula: 0.7<f / f12<1.2, f is the focal length of the optical system, and f12 is the combined focal length of the first lens and the second lens. The cemented lens formed by the cementation of the first lens and the second lens provides a portion of positive refractive power for the optical system, which is used to adjust the overall refractive power of the optical system, converge the light and smoothly transition to the third lens to the seventh lens; by limiting f / f12<1.2, high-order aberrations caused by excessive refractive power can be avoided, and by limiting f / f12>0.7, it can ensure that a sufficiently large convergence ability is provided, reducing the pressure of the third lens to the seventh lens in processing light.

[0047] In one embodiment, the optical system satisfies the conditional formula: |f6 / R61|<11, f6 is the focal length of the sixth lens, and R61 is the radius of curvature of the object side of the sixth lens at the optical axis. This can avoid excessive bending of the object side of the sixth lens at the optical axis, reduce the difficulty of lens processing, and also avoid excessive refractive power of the sixth lens. The refractive power is evenly distributed in the optical system, which can effectively balance the aberrations generated by the first lens to the fifth lens and improve the resolution.

[0048] In one embodiment, the optical system satisfies the conditional formula: 0.9<|R71-R72| / |R71+R72|<3.5, R71 is the radius of curvature of the object side of the seventh lens at the optical axis, and R72 is the radius of curvature of the image side of the seventh lens at the optical axis. By reasonably limiting the range of |R71-R72| / |R71+R72|, it is helpful to correct the aberrations generated by the optical system at a large aperture, so that the refractive power of the optical system in the direction perpendicular to the optical axis is uniformly configured, and the distortion and aberration generated by the first lens to the sixth lens are effectively corrected, while avoiding excessive bending of the seventh lens, reducing the difficulty of molding and manufacturing the seventh lens.

[0049] In one embodiment, the optical system satisfies the conditional formula: 0.18<∑CT / ∑AT<2.7, ∑CT is the sum of the thicknesses of the first lens to the seventh lens on the optical axis, and ∑AT is the sum of the air spacings between adjacent lenses from the first lens to the seventh lens on the optical axis. By reasonably limiting the range of ∑CT / ∑AT, it is beneficial to reasonably control the distance between lenses and realize a compact structure of the optical system. If ∑CT / ∑AT>2.7, the lenses are arranged too closely, which is not conducive to assembly. If ∑CT / ∑AT<0.18, the spacing between the lenses is too large, which is not conducive to the miniaturization design of the optical system.

[0050] In one embodiment, the optical system satisfies the conditional formula: FNO≤2.3, where FNO is the aperture number of the optical system. The aperture of the present application is placed in front, and the entrance pupil diameter is the light entrance of the optical system. By limiting the appropriate range of FNO, it can be ensured that the optical system has sufficient light intake, and the illumination intensity of a single pixel point is increased, thereby improving the shooting effect in a dark environment. In addition, the increase in aperture will reduce the size of the Airy disk, thereby having a higher resolution limit. By reasonably configuring the refractive power of the lens, the design requirements of high pixels can be met.

[0051] In one embodiment, the optical system satisfies the conditional formula: TTL / ImgH<1.55, TTL is the distance from the object side of the first lens in the optical system to the imaging plane on the optical axis, and ImgH is half of the image height corresponding to the maximum field angle of the optical system. ImgH determines the size of the photosensitive element. The larger the ImgH, the larger the size of the maximum photosensitive element that can be supported. By limiting the appropriate range of TTL / ImgH, the optical system can be matched with a high-pixel photosensitive element; the reduction of TTL compresses the length of the entire optical system, making it easy to achieve ultra-thinness and miniaturization of the optical system. Reasonable configuration of the size and refractive power of the lens is conducive to maintaining the compactness of the optical system structure and to achieving good imaging quality for the optical system.

[0052] The present application is described in detail below through five specific embodiments.

[0053] Embodiment 1

[0054] like Figure 1 As shown, the straight line 11 represents the optical axis, the side of the first lens L1 away from the second lens L2 is the object side 12, and the side of the seventh lens L7 away from the sixth lens L6 is the image side 13. In the optical system provided by this embodiment, from the object side 12 to the image side 13 are the aperture STO, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the infrared filter element IRCF.

[0055] The first lens L1 has positive refractive power and is made of plastic. Its object-side surface S1 is convex near the optical axis and at the circumference, and its image-side surface S2 is convex near the optical axis and at the circumference, and both are aspherical.

[0056] The second lens L2 has negative refractive power and is made of plastic. Its object-side surface S3 is concave near the optical axis and at the circumference, and its image-side surface S4 is convex near the optical axis and at the circumference, and both are aspherical.

[0057] The third lens L3 has negative refractive power and is made of plastic. Its object-side surface S5 is concave near the optical axis and at the circumference, and its image-side surface S6 is concave near the optical axis and at the circumference, and both are aspherical.

[0058] The fourth lens L4 has negative refractive power and is made of plastic. Its object-side surface S7 is convex near the optical axis and at the circumference, and its image-side surface S8 is concave near the optical axis and at the circumference, and both are aspherical.

[0059] The fifth lens L5 has positive refractive power and is made of plastic. Its object-side surface S9 is convex near the optical axis and concave at the circumference. Its image-side surface S10 is convex near the optical axis and at the circumference, and both are aspherical.

[0060] The sixth lens L6 has positive refractive power and is made of plastic. Its object-side surface S11 is convex near the optical axis and concave at the circumference. Its image-side surface S12 is convex near the optical axis and at the circumference, and both are aspherical.

[0061] The seventh lens L7 has negative refractive power and is made of plastic. Its object-side surface S13 is concave at the near optical axis and at the circumference, its image-side surface S14 is concave at the near optical axis, and its image-side surface S14 is convex at the circumference, and both are aspherical.

[0062] The stop STO may be located on the object side of the first lens L1 or between any two adjacent lenses. In this embodiment, the stop STO is disposed on the object side of the first lens L1.

[0063] The infrared filter element IRCF is arranged after the seventh lens L7, and includes an object-side surface S15 and an image-side surface S16. The infrared filter element IRCF is used to filter out infrared light so that the light incident on the imaging surface is visible light. The wavelength of visible light is 380nm-780nm. The material of the infrared filter element IRCF is glass.

[0064] The imaging plane S17 is the plane where the image of the object is formed after the light passes through the optical system.

[0065] Table 1a shows the characteristic table of the optical system of this embodiment, wherein the radius of curvature in this embodiment is the radius of curvature of each lens at the near optical axis, and the reference wavelength of the refractive index and the Abbe number is 587 nm.

[0066] Table 1a

[0067]

[0068] Wherein, f is the focal length of the optical system, FNO is the aperture number of the optical system, FOV is the maximum field angle of the optical system, and TTL is the distance from the object side of the first lens to the imaging plane of the optical system on the optical axis.

[0069] In this embodiment, the object-side surface and the image-side surface of the first lens L1 to the seventh lens L7 are all aspherical surfaces, and the surface shape of each aspherical lens can be defined by but not limited to the following aspherical surface formula:

[0070]

[0071] Among them, 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 distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the aspherical vertex, k is the cone constant, and Ai is the coefficient corresponding to the i-th high-order term in the aspherical surface shape formula.

[0072] Table 1b gives the high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 that can be used for each aspherical mirror surface S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14 in the first embodiment.

[0073] Table 1b

[0074]

[0075]

[0076] Figure 2 The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the first embodiment are shown. Among them, the longitudinal spherical aberration curve represents the deviation of the focal point of light rays of different wavelengths after passing through the lenses of the optical system, and the reference wavelengths of the longitudinal spherical aberration curve are 656.2725nm, 587.5618nm, 546.0740nm, 486.1327nm and 435.8343nm; the astigmatism curve represents the meridional image curvature and the sagittal image curvature, wherein S represents the sagittal direction, T represents the meridional direction, and the reference wavelength of the astigmatism curve is 546.0740nm; the distortion curve represents the distortion magnitude values ​​corresponding to different field angles, and the reference wavelength of the distortion curve is 546.0740nm. According to Figure 2 It can be seen that the optical system provided in the first embodiment can achieve good imaging quality.

[0077] Embodiment 2

[0078] like Figure 3As shown, the straight line 11 represents the optical axis, the side of the first lens L1 away from the second lens L2 is the object side 12, and the side of the seventh lens L7 away from the sixth lens L6 is the image side 13. In the optical system provided by this embodiment, from the object side 12 to the image side 13 are the aperture STO, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the infrared filter element IRCF.

[0079] The first lens L1 has positive refractive power and is made of plastic. Its object side surface S1 is convex at the near optical axis and at the circumference, and its image side surface S2 is concave at the near optical axis. Its image side surface S2 is convex at the near optical axis and at the circumference, and both are aspherical.

[0080] The second lens L2 has negative refractive power and is made of plastic. Its object-side surface S3 is convex at the near optical axis and concave at the circumference. Its image-side surface S4 is concave at the near optical axis and convex at the circumference, and both are aspherical.

[0081] The third lens L3 has negative refractive power and is made of plastic. Its object-side surface S5 is concave near the optical axis and at the circumference, and its image-side surface S6 is concave near the optical axis and at the circumference, and both are aspherical.

[0082] The fourth lens L4 has positive refractive power and is made of plastic. Its object-side surface S7 is convex at the near optical axis and at the circumference, its image-side surface S8 is concave at the near optical axis, and its image-side surface S8 is convex at the circumference, and both are aspherical.

[0083] The fifth lens L5 has positive refractive power and is made of plastic. Its object-side surface S9 is convex near the optical axis and concave at the circumference. Its image-side surface S10 is convex near the optical axis and at the circumference, and both are aspherical.

[0084] The sixth lens L6 has negative refractive power and is made of plastic. Its object-side surface S11 is concave near the optical axis and at the circumference, and its image-side surface S12 is convex near the optical axis and at the circumference, and both are aspherical.

[0085] The seventh lens L7 has negative refractive power and is made of plastic. Its object-side surface S13 is concave at the near optical axis and at the circumference, its image-side surface S14 is concave at the near optical axis, and its image-side surface S14 is convex at the circumference, and both are aspherical.

[0086] The stop STO may be located on the object side of the first lens L1 or between any two adjacent lenses. In this embodiment, the stop STO is disposed on the object side of the first lens L1.

[0087] The infrared filter element IRCF is arranged after the seventh lens L7, and includes an object-side surface S15 and an image-side surface S16. The infrared filter element IRCF is used to filter out infrared light so that the light incident on the imaging surface is visible light. The wavelength of visible light is 380nm-780nm. The material of the infrared filter element IRCF is glass.

[0088] The imaging plane S17 is the plane where the image of the object is formed after the light passes through the optical system.

[0089] Table 2a shows the characteristic table of the optical system of this embodiment, wherein the radius of curvature in this embodiment is the radius of curvature of each lens at the near optical axis, and the reference wavelength of the refractive index and the Abbe number is 587 nm.

[0090] Table 2a

[0091]

[0092] Wherein, f is the focal length of the optical system, FNO is the aperture number of the optical system, FOV is the maximum field angle of the optical system, and TTL is the distance from the object side of the first lens to the imaging plane of the optical system on the optical axis.

[0093] Table 2b gives the high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 that can be used for each aspherical mirror surface S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14 in the second embodiment, wherein the surface shape of each aspherical surface can be defined by the formula given in the first embodiment.

[0094] Table 2b

[0095] Surface number S1 S2 S3 S4 S5 S6 S7 K 1.7333E-01 -9.9000E+01 -9.9000E+01 -9.9000E+01 9.9000E+01 8.3279E+00 -6.8126E+01 A4 -1.5044E-02 -1.7262E-01 -1.7262E-01 -6.7093E-02 -3.9924E-02 2.7319E-02 -3.5703E-02 A6 1.2765E-01 7.6055E-01 7.6055E-01 -1.9204E-01 -3.7966E-01 -4.8762E-02 1.6487E-01 A8 -9.3096E-01 -4.9819E+00 -4.9819E+00 5.9814E-01 1.1696E+00 -8.0679E-02 -5.4710E-01 A10 4.0054E+00 1.7568E+01 1.7568E+01 -2.4387E+00 -4.5098E+00 3.2176E-01 1.1804E+00 A12 -1.0741E+01 -3.5280E+01 -3.5280E+01 6.8831E+00 1.2275E+01 -2.7050E-01 -1.7247E+00 A14 1.7953E+01 4.0164E+01 4.0164E+01 -1.1539E+01 -1.9774E+01 1.1758E-02 1.6455E+00 A16 -1.8121E+01 -2.2499E+01 -2.2499E+01 1.1487E+01 1.8761E+01 7.0632E-02 -9.9259E-01 A18 1.0044E+01 2.7232E+00 2.7232E+00 -6.4267E+00 -9.9282E+00 -1.0264E-02 3.4939E-01 A20 -2.3314E+00 1.5826E+00 1.5826E+00 1.5542E+00 2.2702E+00 -7.3503E-03 -5.4620E-02 Surface number S8 S9 S10 S11 S12 S13 S14 K -6.5729E+01 7.3532E+01 -1.4297E+01 -9.0036E+01 -2.9782E+01 1.8339E-01 -5.6209E+00 A4 -1.5022E-01 -1.3845E-01 -2.5639E-01 2.5861E-01 5.4935E-01 2.7402E-01 -3.0815E-02 A6 3.5314E-01 1.8813E-01 5.1265E-01 -3.6808E-01 -8.6815E-01 -5.6449E-01 -8.5689E-02 A8 -9.4454E-01 9.3384E-02 -3.8291E-01 2.9732E-01 8.0109E-01 4.4567E-01 6.7601E-02 A10 1.7090E+00 -6.4611E-01 -6.9217E-02 -1.7933E-01 -5.2540E-01 -1.9057E-01 -2.1116E-02 A12 -2.1520E+00 8.7105E-01 3.0497E-01 1.8640E-02 2.3503E-01 4.9068E-02 2.8752E-03 A14 1.8378E+00 -6.0435E-01 -2.1868E-01 5.1001E-02 -6.7973E-02 -7.7706E-03 -1.3602E-05 A16 -1.0138E+00 2.3432E-01 7.7193E-02 -3.1707E-02 1.2020E-02 7.3261E-04 -4.4898E-05 A18 3.2407E-01 -4.7444E-02 -1.4089E-02 7.5442E-03 -1.1750E-03 -3.6960E-05 5.1321E-06 A20 -4.4936E-02 3.8245E-03 1.0653E-03 -6.5760E-04 4.8477E-05 7.3623E-07 -1.8735E-07

[0096] Figure 4 The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the second embodiment are shown. Among them, the longitudinal spherical aberration curve represents the deviation of the focal point of light rays of different wavelengths after passing through the lenses of the optical system, and the reference wavelengths of the longitudinal spherical aberration curve are 656.2725nm, 587.5618nm, 546.0740nm, 486.1327nm and 435.8343nm; the astigmatism curve represents the meridional image curvature and the sagittal image curvature, wherein S represents the sagittal direction, T represents the meridional direction, and the reference wavelength of the astigmatism curve is 546.0740nm; the distortion curve represents the distortion magnitude values ​​corresponding to different field angles, and the reference wavelength of the distortion curve is 546.0740nm. According to Figure 4 It can be seen that the optical system provided in the second embodiment can achieve good imaging quality.

[0097] Embodiment 3

[0098] like Figure 5 As shown, the straight line 11 represents the optical axis, the side of the first lens L1 away from the second lens L2 is the object side 12, and the side of the seventh lens L7 away from the sixth lens L6 is the image side 13. In the optical system provided by this embodiment, from the object side 12 to the image side 13 are the aperture STO, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the infrared filter element IRCF.

[0099] The first lens L1 has positive refractive power and is made of plastic. Its object-side surface S1 is convex near the optical axis and at the circumference, and its image-side surface S2 is convex near the optical axis and at the circumference, and both are aspherical.

[0100] The second lens L2 has negative refractive power and is made of plastic. Its object-side surface S3 is concave at the near optical axis and at the circumference, its image-side surface S4 is concave at the near optical axis, and its image-side surface S4 is convex at the circumference, and both are aspherical.

[0101] The third lens L3 has positive refractive power and is made of plastic. Its object-side surface S5 is concave at the near optical axis and at the circumference, its image-side surface S6 is convex at the near optical axis, and its image-side surface S6 is concave at the circumference, and both are aspherical.

[0102] The fourth lens L4 has negative refractive power and is made of plastic. Its object-side surface S7 is concave at the near optical axis and is convex at the circumference. Its image-side surface S8 is concave at the near optical axis and is convex at the circumference, and both are aspherical.

[0103] The fifth lens L5 has positive refractive power and is made of plastic. Its object-side surface S9 is convex near the optical axis and concave at the circumference. Its image-side surface S10 is convex near the optical axis and at the circumference, and both are aspherical.

[0104] The sixth lens L6 has negative refractive power and is made of plastic. Its object-side surface S11 is concave near the optical axis and at the circumference, and its image-side surface S12 is convex near the optical axis and at the circumference, and both are aspherical.

[0105] The seventh lens L7 has negative refractive power and is made of plastic. Its object-side surface S13 is concave at the near optical axis and at the circumference, its image-side surface S14 is concave at the near optical axis, and its image-side surface S14 is convex at the circumference, and both are aspherical.

[0106] The stop STO may be located on the object side of the first lens L1 or between any two adjacent lenses. In this embodiment, the stop STO is disposed on the object side of the first lens L1.

[0107] The infrared filter element IRCF is arranged after the seventh lens L7, and includes an object-side surface S15 and an image-side surface S16. The infrared filter element IRCF is used to filter out infrared light so that the light incident on the imaging surface is visible light. The wavelength of visible light is 380nm-780nm. The material of the infrared filter element IRCF is glass.

[0108] The imaging plane S17 is the plane where the image of the object is formed after the light passes through the optical system.

[0109] Table 3a shows the characteristic table of the optical system of this embodiment, wherein the radius of curvature in this embodiment is the radius of curvature of each lens at the near optical axis, and the reference wavelength of the refractive index and the Abbe number is 587 nm.

[0110] Table 3a

[0111]

[0112] Wherein, f is the focal length of the optical system, FNO is the aperture number of the optical system, FOV is the maximum field angle of the optical system, and TTL is the distance from the object side of the first lens to the imaging plane of the optical system on the optical axis.

[0113] Table 3b gives the high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 that can be used for each aspherical mirror surface S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14 in the third embodiment, wherein the surface shape of each aspherical surface can be defined by the formula given in the first embodiment.

[0114] Table 3b

[0115] Surface number S1 S2 S3 S4 S5 S6 S7 K 1.8662E-01 -1.4830E+00 -1.4830E+00 5.5011E+01 6.6213E+01 2.1154E+01 -1.8866E+01 A4 -1.2654E-02 -2.1166E-03 -2.1166E-03 -4.2453E-02 -9.0765E-02 1.2155E-01 1.2383E-01 A6 9.2538E-02 -3.5288E-01 -3.5288E-01 -1.3765E-01 -5.6944E-01 -1.2320E+00 -1.2678E+00 A8 -7.2581E-01 3.9993E+00 3.9993E+00 4.8518E-01 2.1006E+00 4.3860E+00 4.7747E+00 A10 3.3943E+00 -2.3776E+01 -2.3776E+01 -1.8729E+00 -7.3980E+00 -1.1380E+01 -1.1921E+01 A12 -1.0218E+01 8.2067E+01 8.2067E+01 4.3745E+00 1.6560E+01 1.9535E+01 1.9762E+01 A14 1.9833E+01 -1.6944E+02 -1.6944E+02 -6.8292E+00 -2.3280E+01 -2.0645E+01 -2.0849E+01 A16 -2.3955E+01 2.0589E+02 2.0589E+02 6.7251E+00 2.1330E+01 1.3119E+01 1.3310E+01 A18 1.6321E+01 -1.3578E+02 -1.3578E+02 -3.8311E+00 -1.1876E+01 -4.6341E+00 -4.6561E+00 A20 -4.7768E+00 3.7378E+01 3.7378E+01 9.4162E-01 2.9654E+00 6.9887E-01 6.8225E-01 Surface number S8 S9 S10 S11 S12 S13 S14 K -9.9000E+01 1.2206E+01 -1.1820E+01 -9.5516E+01 1.0432E+01 1.5072E+01 -3.7093E+00 A4 -1.5789E-01 -1.8741E-01 -4.9276E-02 6.0654E-01 7.6930E-01 1.9614E-01 2.1394E-02 A6 4.3070E-02 5.4568E-01 3.5108E-01 -1.1636E+00 -1.5191E+00 -6.3423E-01 -2.8744E-01 A8 -2.7787E-01 -9.8463E-01 -6.5217E-01 9.5295E-01 1.5437E+00 6.4823E-01 3.1302E-01 A10 7.9637E-01 8.9627E-01 5.9004E-01 -3.2548E-01 -9.5562E-01 -3.7912E-01 -1.7689E-01 A12 -1.1939E+00 -3.7644E-01 -2.8269E-01 -4.1826E-02 3.7384E-01 1.4251E-01 6.0069E-02 A14 1.1501E+00 7.1282E-03 6.8694E-02 6.7452E-02 -9.2631E-02 -3.4701E-02 -1.2660E-02 A16 -7.2039E-01 5.7125E-02 -5.4853E-03 -1.8847E-02 1.4088E-02 5.2690E-03 1.6229E-03 A18 2.5835E-01 -2.1096E-02 -7.9841E-04 1.7276E-03 -1.1981E-03 -4.5281E-04 -1.1602E-04 A20 -3.8445E-02 2.5045E-03 1.3635E-04 4.8267E-06 4.3470E-05 1.6824E-05 3.5525E-06

[0116] Figure 6 The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the third embodiment are shown. Among them, the longitudinal spherical aberration curve represents the deviation of the focal point of light rays of different wavelengths after passing through the lenses of the optical system, and the reference wavelengths of the longitudinal spherical aberration curve are 656.2725nm, 587.5618nm, 546.0740nm, 486.1327nm and 435.8343nm; the astigmatism curve represents the meridional image curvature and the sagittal image curvature, wherein S represents the sagittal direction, T represents the meridional direction, and the reference wavelength of the astigmatism curve is 546.0740nm; the distortion curve represents the distortion magnitude values ​​corresponding to different field angles, and the reference wavelength of the distortion curve is 546.0740nm. According to Figure 6 It can be seen that the optical system provided in the third embodiment can achieve good imaging quality.

[0117] Embodiment 4

[0118] like Figure 7 As shown, the straight line 11 represents the optical axis, the side of the first lens L1 away from the second lens L2 is the object side 12, and the side of the seventh lens L7 away from the sixth lens L6 is the image side 13. In the optical system provided by this embodiment, from the object side 12 to the image side 13 are the aperture STO, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the infrared filter element IRCF.

[0119] The first lens L1 has positive refractive power and is made of plastic. Its object-side surface S1 is convex near the optical axis and at the circumference, and its image-side surface S2 is convex near the optical axis and at the circumference, and both are aspherical.

[0120] The second lens L2 has negative refractive power and is made of plastic. Its object-side surface S3 is concave at the near optical axis and at the circumference, its image-side surface S4 is concave at the near optical axis, and its image-side surface S4 is convex at the circumference, and both are aspherical.

[0121] The third lens L3 has positive refractive power and is made of plastic. Its object-side surface S5 is concave near the optical axis and at the circumference, and its image-side surface S6 is convex near the optical axis and at the circumference, and both are aspherical.

[0122] The fourth lens L4 has negative refractive power and is made of plastic. Its object-side surface S7 is concave at the near optical axis and at the circumference, its image-side surface S8 is concave at the near optical axis, and its image-side surface S8 is convex at the circumference, and both are aspherical.

[0123] The fifth lens L5 has positive refractive power and is made of plastic. Its object-side surface S9 is convex near the optical axis and concave at the circumference. Its image-side surface S10 is convex near the optical axis and at the circumference, and both are aspherical.

[0124] The sixth lens L6 has negative refractive power and is made of plastic. Its object-side surface S11 is concave near the optical axis and at the circumference, and its image-side surface S12 is convex near the optical axis and at the circumference, and both are aspherical.

[0125] The seventh lens L7 has negative refractive power and is made of plastic. Its object-side surface S13 is convex at the near optical axis and at the circumference, its image-side surface S14 is concave at the near optical axis, and its image-side surface S14 is convex at the circumference, and both are aspherical.

[0126] The stop STO may be located on the object side of the first lens L1 or between any two adjacent lenses. In this embodiment, the stop STO is disposed on the object side of the first lens L1.

[0127] The infrared filter element IRCF is arranged after the seventh lens L7, and includes an object-side surface S15 and an image-side surface S16. The infrared filter element IRCF is used to filter out infrared light so that the light incident on the imaging surface is visible light. The wavelength of visible light is 380nm-780nm. The material of the infrared filter element IRCF is glass.

[0128] The imaging plane S17 is the plane where the image of the object is formed after the light passes through the optical system.

[0129] Table 4a shows the characteristic table of the optical system of this embodiment, wherein the radius of curvature in this embodiment is the radius of curvature of each lens at the near optical axis, and the reference wavelength of the refractive index and the Abbe number is 587 nm.

[0130] Table 4a

[0131]

[0132] Wherein, f is the focal length of the optical system, FNO is the aperture number of the optical system, FOV is the maximum field angle of the optical system, and TTL is the distance from the object side of the first lens to the imaging plane of the optical system on the optical axis.

[0133] Table 4b gives the high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 that can be used for each aspheric mirror surface S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14 in the fourth embodiment, wherein the surface shape of each aspheric surface can be defined by the formula given in the first embodiment.

[0134] Table 4b

[0135] Surface number S1 S2 S3 S4 S5 S6 S7 K 1.6186E-01 1.3416E+01 1.3416E+01 5.4222E+01 -9.7935E+01 1.6840E+01 -2.3495E+01 A4 -9.6509E-03 -1.1224E-01 6.4203E-02 -5.4901E-02 -2.7576E-02 1.9698E-01 2.1031E-01 A6 -3.0555E-02 3.6878E+00 -2.0748E+00 -6.2319E-02 -9.4215E-01 -1.7682E+00 -1.9402E+00 A8 7.2028E-01 -5.2707E+01 2.1980E+01 -1.4561E-01 4.0856E+00 6.8634E+00 6.2600E+00 A10 -6.0527E+00 3.8728E+02 -1.2898E+02 9.6816E-01 -1.2387E+01 -1.7124E+01 -1.1800E+01 A12 2.6397E+01 -1.6830E+03 4.4981E+02 -3.1731E+00 2.3413E+01 2.7897E+01 1.3848E+01 A14 -6.6353E+01 4.5727E+03 -9.5569E+02 5.5661E+00 -2.6595E+01 -2.8986E+01 -9.7902E+00 A16 9.6863E+01 -7.8629E+03 1.2129E+03 -5.4135E+00 1.7436E+01 1.8677E+01 3.7286E+00 A18 -7.6369E+01 8.3216E+03 -8.4416E+02 2.7852E+00 -5.5289E+00 -6.8273E+00 -5.3360E-01 A20 2.5163E+01 -4.9497E+03 2.4749E+02 -6.5535E-01 3.3885E-01 1.0777E+00 -2.7420E-02 Surface number S8 S9 S10 S11 S12 S13 S14 K -5.4937E+01 1.4346E+01 -2.2597E+01 -9.7402E+01 3.5911E+01 -9.8753E+01 -4.6931E+00 A4 -7.7229E-02 -1.1282E-01 -2.4566E-01 3.8719E-01 6.3480E-01 4.6010E-02 -1.7561E-01 A6 -6.1201E-01 3.8118E-01 1.1776E+00 -5.5713E-01 -1.0671E+00 -1.2697E-01 1.4633E-01 A8 1.4717E+00 -6.1771E-01 -1.7891E+00 2.9272E-01 9.7084E-01 1.4878E-01 -8.0733E-02 A10 -1.7235E+00 5.4167E-01 1.5274E+00 8.0498E-03 -5.6683E-01 -9.4672E-02 3.0468E-02 A12 9.1202E-01 -3.5427E-01 -8.4541E-01 -1.1241E-01 2.1670E-01 3.4560E-02 -7.8705E-03 A14 1.5110E-01 1.9688E-01 3.1175E-01 7.2534E-02 -5.3730E-02 -7.5240E-03 1.3426E-03 A16 -4.5546E-01 -8.0997E-02 -7.4035E-02 -2.2417E-02 8.3161E-03 9.7335E-04 -1.4310E-04 A18 2.1199E-01 1.9410E-02 1.0230E-02 3.5402E-03 -7.2972E-04 -6.9454E-05 8.6271E-06 A20 -3.2171E-02 -1.9417E-03 -6.2410E-04 -2.3051E-04 2.7699E-05 2.1135E-06 -2.2561E-07

[0136] Figure 8 The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the fourth embodiment are shown. Among them, the longitudinal spherical aberration curve represents the deviation of the focal point of light rays of different wavelengths after passing through the lenses of the optical system, and the reference wavelengths of the longitudinal spherical aberration curve are 656.2725nm, 587.5618nm, 546.0740nm, 486.1327nm and 435.8343nm; the astigmatism curve represents the meridional image curvature and the sagittal image curvature, wherein S represents the sagittal direction, T represents the meridional direction, and the reference wavelength of the astigmatism curve is 546.0740nm; the distortion curve represents the distortion magnitude values ​​corresponding to different field angles, and the reference wavelength of the distortion curve is 546.0740nm. According to Figure 8 It can be seen that the optical system provided in the fourth embodiment can achieve good imaging quality.

[0137] Embodiment 5

[0138] like Fig. 9 As shown, the straight line 11 represents the optical axis, the side of the first lens L1 away from the second lens L2 is the object side 12, and the side of the seventh lens L7 away from the sixth lens L6 is the image side 13. In the optical system provided by this embodiment, from the object side 12 to the image side 13 are the aperture STO, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the infrared filter element IRCF.

[0139] The first lens L1 has positive refractive power and is made of plastic. Its object-side surface S1 is convex near the optical axis and at the circumference, and its image-side surface S2 is convex near the optical axis and at the circumference, and both are aspherical.

[0140] The second lens L2 has negative refractive power and is made of plastic. Its object-side surface S3 is concave near the optical axis and at the circumference, and its image-side surface S4 is convex near the optical axis and at the circumference, and both are aspherical.

[0141] The third lens L3 has negative refractive power and is made of plastic. Its object-side surface S5 is convex at the near optical axis and concave at the circumference. Its image-side surface S6 is concave at the near optical axis and at the circumference, and both are aspherical.

[0142] The fourth lens L4 has negative refractive power and is made of plastic. Its object-side surface S7 is convex near the optical axis and at the circumference, and its image-side surface S8 is concave near the optical axis and at the circumference, and both are aspherical.

[0143] The fifth lens L5 has positive refractive power and is made of plastic. Its object-side surface S9 is convex near the optical axis and concave at the circumference. Its image-side surface S10 is convex near the optical axis and at the circumference, and both are aspherical.

[0144] The sixth lens L6 has positive refractive power and is made of plastic. Its object-side surface S11 is concave near the optical axis and at the circumference, and its image-side surface S12 is convex near the optical axis and at the circumference, and both are aspherical.

[0145] The seventh lens L7 has negative refractive power and is made of plastic. Its object-side surface S13 is concave at the near optical axis and is convex at the circumference. Its image-side surface S14 is concave at the near optical axis and is convex at the circumference, and both are aspherical.

[0146] The stop STO may be located on the object side of the first lens L1 or between any two adjacent lenses. In this embodiment, the stop STO is disposed on the object side of the first lens L1.

[0147] The infrared filter element IRCF is arranged after the seventh lens L7, and includes an object-side surface S15 and an image-side surface S16. The infrared filter element IRCF is used to filter out infrared light so that the light incident on the imaging surface is visible light. The wavelength of visible light is 380nm-780nm. The material of the infrared filter element IRCF is glass.

[0148] The imaging plane S17 is the plane where the image of the object is formed after the light passes through the optical system.

[0149] Table 5a shows the characteristic table of the optical system of this embodiment, wherein the radius of curvature in this embodiment is the radius of curvature of each lens at the near optical axis, and the reference wavelength of the refractive index and the Abbe number is 587 nm.

[0150] Table 5a

[0151]

[0152] Wherein, f is the focal length of the optical system, FNO is the aperture number of the optical system, FOV is the maximum field angle of the optical system, and TTL is the distance from the object side of the first lens to the imaging plane of the optical system on the optical axis.

[0153] Table 5b gives the high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 of the aspheric mirror surfaces S1, S2, S3, S4, S5, S6, S7, S8, S9, S10, S11, S12, S13, S14 that can be used in the fifth embodiment, wherein the surface shape of each aspheric surface can be defined by the formula given in the first embodiment.

[0154] Table 5b

[0155] Surface number S1 S2 S3 S4 S5 S6 S7 K 1.8537E-02 1.3886E+01 1.3886E+01 2.8122E+01 -9.9000E+01 1.2257E+00 -9.8357E+01 A4 -2.3607E-02 1.8746E-01 1.8746E-01 -6.5014E-02 -4.3557E-02 4.5891E-02 -1.8453E-01 A6 1.7809E-01 -3.2430E+00 -3.2430E+00 -1.8391E-01 -6.8862E-02 1.1436E-01 6.2818E-01 A8 -1.2617E+00 2.8138E+01 2.8138E+01 -1.6059E-02 -2.0685E+00 -1.5333E+00 -1.3853E+00 A10 4.6321E+00 -1.4350E+02 -1.4350E+02 1.2546E+00 9.2460E+00 4.9772E+00 1.8566E+00 A12 -9.1713E+00 4.4905E+02 4.4905E+02 -2.3966E+00 -1.9355E+01 -8.6981E+00 -1.4346E+00 A14 7.9192E+00 -8.6789E+02 -8.6789E+02 3.3352E-01 2.3035E+01 9.2586E+00 3.6395E-01 A16 1.7807E+00 1.0083E+03 1.0083E+03 3.9663E+00 -1.5201E+01 -5.9948E+00 2.6565E-01 A18 -8.0306E+00 -6.4441E+02 -6.4441E+02 -4.7081E+00 4.6156E+00 2.1763E+00 -1.7823E-01 A20 4.0223E+00 1.7392E+02 1.7392E+02 1.6964E+00 -2.9384E-01 -3.4157E-01 2.3341E-02 Surface number S8 S9 S10 S11 S12 S13 S14 K -9.8761E+01 -1.2904E+01 -3.0578E+01 -5.4585E+01 -3.3931E+01 -1.1145E-01 -1.0530E+01 A4 -1.1363E-01 -1.9284E-01 5.1025E-02 5.1126E-01 3.7663E-01 2.2183E-01 2.6175E-02 A6 -3.4649E-01 2.1966E-01 -4.6233E-01 -1.4916E+00 -4.8186E-01 -4.5359E-01 -1.0789E-01 A8 2.0114E+00 -2.6642E-02 1.4830E+00 2.8796E+00 3.1900E-01 3.5779E-01 7.1539E-02 A10 -5.5619E+00 7.5528E-02 -2.4963E+00 -3.9340E+00 -1.6387E-01 -1.6148E-01 -2.5238E-02 A12 8.9773E+00 -1.1454E+00 2.4384E+00 3.4585E+00 7.2315E-02 4.7427E-02 5.5689E-03 A14 -9.0730E+00 2.2682E+00 -1.4358E+00 -1.8918E+00 -2.3772E-02 -9.2667E-03 -8.1194E-04 A16 5.6475E+00 -2.0504E+00 5.0485E-01 6.2465E-01 4.9647E-03 1.1603E-03 7.6471E-05 A18 -1.9789E+00 9.1698E-01 -9.8131E-02 -1.1451E-01 -5.7276E-04 -8.3965E-05 -4.1137E-06 A20 3.0088E-01 -1.6440E-01 8.1450E-03 8.9771E-03 2.7653E-05 2.6608E-06 9.0874E-08

[0156] Fig.10 The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the fifth embodiment are shown. Among them, the longitudinal spherical aberration curve represents the deviation of the focal point of light rays of different wavelengths after passing through the lenses of the optical system, and the reference wavelengths of the longitudinal spherical aberration curve are 656.2725nm, 587.5618nm, 546.0740nm, 486.1327nm and 435.8343nm; the astigmatism curve represents the meridional image curvature and the sagittal image curvature, wherein S represents the sagittal direction, T represents the meridional direction, and the reference wavelength of the astigmatism curve is 546.0740nm; the distortion curve represents the distortion magnitude values ​​corresponding to different field angles, and the reference wavelength of the distortion curve is 546.0740nm. According to Fig.10 It can be seen that the optical system provided in the fifth embodiment can achieve good imaging quality.

[0157] Table 6 shows the values ​​of (CT1+CT2) / TTL, SD11 / ImgH, FNO / SD11, f / f12, |f6 / R61|, ΣCT / ΣAT, FNO, TTL / ImgH, |R71-R72| / |R71+R72| of the optical systems of the first to fifth embodiments.

[0158] Table 6

[0159]

[0160]

[0161] It can be seen from Table 6 that all embodiments can satisfy: (CT1+CT2) / TTL>0.23, SD11 / ImgH<0.28, FNO / SD11≥0.24mm -1 , 0.7<f / f12<1.2, |f6 / R61|<11, 0.9<|R71-R72| / |R71+R72|<3.5, 0.18<∑CT / ΣAT<2.7, FNO≤2.3, TTL / ImgH<1.55.

[0162] See also Fig.11 The optical system involved in the present application is applied to a camera module 20 in a terminal device 30. The terminal device 30 may be a mobile phone, a tablet computer, a drone, a computer, etc. The photosensitive element of the camera module 20 is located on the image side of the optical system, and the camera module 20 is assembled inside the terminal device 30.

[0163] The present application provides a camera module, including a photosensitive element and an optical system provided in an embodiment of the present application, wherein the photosensitive element is located on the image side of the optical system, and is used to convert light passing through the first lens to the seventh lens and incident on the electronic photosensitive element into an electrical signal of an image. The electronic photosensitive element may be a complementary metal oxide semiconductor (CMOS) or a charge-coupled device (CCD). By installing the optical system in the camera module, the camera module has the characteristics of miniaturization and a small head, and the molding yield of the lens is improved.

[0164] The present application also provides a terminal device, which includes the camera module provided in the embodiment of the present application. The terminal device can be a mobile phone, a tablet computer, a drone, a computer, etc. By installing the camera module in the terminal device, the terminal device has the characteristics of miniaturization and a small head, and the molding yield of the lens is improved.

[0165] The above is a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications are also considered to be within the scope of protection of the present application.

Claims

1. An optical system, characterized in that: There are 7 lenses with refractive power, which are arranged in sequence from the object side to the image side: A first lens has positive refractive power, and the object side surface of the first lens is convex at the near optical axis; The second lens has negative refractive power; The third lens has refractive power; a fourth lens having refractive power, wherein the image side surface of the fourth lens is concave at the near optical axis; A fifth lens element having positive refractive power, wherein both the object side surface and the image side surface of the fifth lens element are convex surfaces near the optical axis; a sixth lens element having refractive power, wherein the image side surface of the sixth lens element is a convex surface near the optical axis; A seventh lens element having negative refractive power, wherein the image side surface of the seventh lens element is a concave surface near the optical axis, and the image side surface of the seventh lens element is an aspherical surface; The image side surface of the first lens and the object side surface of the second lens are cemented; The optical system satisfies the condition: SD11 / ImgH<0.28, SD11 is the maximum effective aperture of the object side of the first lens, and ImgH is half of the image height corresponding to the maximum field angle of the optical system.

2. The optical system according to claim 1, characterized in that The optical system satisfies the condition: (CT1+CT2) / TTL>0.23, CT1 is the thickness of the first lens on the optical axis, CT2 is the thickness of the second lens on the optical axis, and TTL is the distance from the object side surface to the imaging surface on the optical axis in the optical system.

3. The optical system according to claim 1, characterized in that The optical system satisfies the condition: FNO / SD11≥0.24mm -1 , FNO is the aperture number of the optical system, and SD11 is the maximum effective aperture of the object side of the first lens.

4. The optical system according to claim 1, characterized in that The optical system satisfies the condition: 0.7<f / f12<1.2, f is the focal length of the optical system, and f12 is the combined focal length of the first lens and the second lens.

5. The optical system according to claim 1, characterized in that The optical system satisfies the condition: |f6 / R61|<11, f6 is the focal length of the sixth lens, and R61 is the radius of curvature of the object side of the sixth lens at the optical axis.

6. The optical system according to claim 1, characterized in that The optical system satisfies the condition: 0.9<|R71-R72| / |R71+R72|<3.5, R71 is the curvature radius of the object side surface of the seventh lens at the optical axis, and R72 is the curvature radius of the image side surface of the seventh lens at the optical axis.

7. The optical system according to claim 1, characterized in that The optical system satisfies the condition: 0.18<∑CT / ∑AT<2.7, ΣCT is the sum of thicknesses of the first lens to the seventh lens on the optical axis, and ΣAT is the sum of air spaces between adjacent lenses from the first lens to the seventh lens on the optical axis.

8. The optical system according to claim 1, characterized in that The optical system satisfies the condition: 2.06 <FNO≤2.3, FNO is the aperture number of the optical system.

9. The optical system according to claim 1, characterized in that The optical system satisfies the condition: TTL / ImgH<1.55, TTL is the distance from the object side surface of the first lens in the optical system to the imaging surface on the optical axis, and ImgH is half of the image height corresponding to the maximum field angle of the optical system.

10. A camera module, characterized in that: The optical system comprises a photosensitive element and the optical system as claimed in any one of claims 1 to 9, wherein the photosensitive element is located on the image side of the optical system.

11. A terminal device, characterized in that: Comprising the camera module as claimed in claim 10.

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