Optical systems, lens modules and electronic devices

Abstract

The present invention provides an optical system, a lens module and an electronic device. The optical system sequentially includes, along the optical axis direction from the object side to the image side: a first lens with positive optical power; a second lens with optical power; a third lens with negative optical power; a fourth lens with positive optical power, wherein the object side surface and the image side surface of the fourth lens are both convex surfaces; a fifth lens with negative optical power; wherein, the optical system satisfies the following relational expression: 0.2 < TD / f < 0.5; TD is the distance on the optical axis from the object side surface of the first lens to the image side surface of the fifth lens, and f is the effective focal length of the optical system. By reasonably configuring the surface types and optical powers of the lenses from the first lens to the fifth lens, the long focal length telescopic function is realized and the requirements of miniaturization and high imaging quality are met.

Description

Technical Field

[0001] The present invention belongs to the field of optical imaging, and particularly relates to an optical system, a lens module, and an electronic device. Background Art

[0002] In recent years, with the continuous development of technologies related to smart phones, the requirements for miniaturization of mobile phone lenses and high-quality imaging quality have been increasing day by day. Moreover, with the advancement of semiconductor manufacturing processes and the reduction of the pixel size of photosensitive elements, electronic products with a thin, light, short, and excellent-function form are bound to become a development trend. The application of camera modules is becoming more and more extensive, and it will also become a major trend in the future development of technology to install camera modules in various intelligent electronic products, vehicle-mounted devices, identification systems, and entertainment and sports equipment.

[0003] Nowadays, it has become the mainstream in the mobile phone market for mobile phones to be equipped with one, two, or even more than three lenses with different imaging functions. The volume of existing lenses is not easy to reduce, it is difficult to miniaturize, and the imaging quality of shooting distant details is not good, which cannot conform to the general trend of technological development and is difficult to be applied to the mainstream mobile phone market. Summary of the Invention

[0004] The purpose of the present invention is to provide an optical system that can simultaneously meet the requirements of telephoto function, miniaturization, and high imaging quality.

[0005] To achieve the purpose of the present invention, the following technical solutions are provided:

[0006] In a first aspect, the present invention provides an optical system that sequentially includes, from the object side to the image side along the optical axis direction: a first lens with a positive focal power; a second lens with a focal power; a third lens with a negative focal power; a fourth lens with a positive focal power, and both the object side surface and the image side surface of the fourth lens are convex surfaces; a fifth lens with a negative focal power; wherein, the optical system satisfies the following relational expression: 0.2 < TD / f < 0.5; TD is the distance on the optical axis from the object side surface of the first lens to the image side surface of the fifth lens, and f is the effective focal length of the optical system. By reasonably configuring the surface types and focal powers of each lens from the first lens to the fifth lens, the long focal length telephoto function is realized, and the requirements of miniaturization and high imaging quality are met. When TD / f ≥ 0.5, the structure of the optical lens is not compact enough, resulting in too long a lens length and being not conducive to the assembly of the lens elements. When TD / f ≤ 0.2, the length of the optical lens is too small, it is difficult to correct lens aberrations, and the telephoto imaging quality is not good. By reasonably setting the value of TD / f, further reasonably distributing the lens focal powers and configuring the lens shapes, while meeting the miniaturization of the lens, it is also conducive to improving the telephoto ability of the lens.

[0007] In one embodiment, the optical system satisfies the conditional formula: -1 < f12 / f345 < -0.2; where f12 is the combined focal length of the first lens and the second lens, and f345 is the combined focal length of the third lens, the fourth lens, and the fifth lens. By controlling the magnitudes and directions of the combined focal length of the first lens and the second lens and the combined focal length of the third lens, the fourth lens, and the fifth lens, the camera lens can achieve the balance of system spherical aberration, obtain good imaging quality in the on-axis field of view, and at the same time, the principal plane of the system can be far from the imaging plane, enhancing the telephoto function of the lens.

[0008] In one embodiment, the optical system satisfies the conditional formula: 0.3 < f1 / f < 0.5; where f1 is the effective focal length of the first lens. When f1 / f ≥ 0.5, the optical power of the first lens is too large, it is difficult for the negative lens of the system to correct aberrations, and the imaging quality is poor; when f1 / f ≤ 0.3, the optical power of the first lens is unevenly distributed, resulting in insufficient telephoto ability of the optical lens. Reasonably distributing the optical power of the first lens is beneficial to enhancing the telephoto ability of the system, reducing the system spherical aberration at the same time, and improving the clarity of the image plane.

[0009] In one embodiment, the optical system satisfies the conditional formula: -1.5 < f5 / f < -0.5; where f5 is the effective focal length of the fifth lens. By configuring the fifth lens with negative optical power and reasonably setting the value of f5 / f, the lens can achieve the telephoto function with a longer focal length through a fifth lens with a smaller size, and can achieve the effect of providing a narrower field of view and forming a larger target image.

[0010] In one embodiment, the optical system satisfies the following conditional formula: 0 < R4 / R5 < 3.0; where R4 is the curvature radius of the object side surface of the second lens, and R5 is the curvature radius of the image side surface of the second lens. When R4 / R5 ≤ 0, the surface shape of the second lens will be overly curved, with poor forming, affecting the manufacturing yield. When R4 / R5 ≥ 3, the surface shape of the second lens is too smooth, resulting in difficult aberration correction, excessive astigmatism in the outer field of view, and affecting the imaging quality of the telephoto lens. By adjusting the curvature radius of the second lens, the processing feasibility of the second lens is ensured, and at the same time, the system spherical aberration and astigmatism are effectively corrected, improving the imaging quality of the camera.

[0011] In one embodiment, the optical system satisfies the following conditional formula: 1.4 < SD11 / SD52 < 2.0. Where SD11 is the maximum effective semi-aperture of the object side surface of the first lens, and SD52 is the maximum effective semi-aperture of the image side surface of the fifth lens. By reasonably setting the value of SD11 / SD52, it is beneficial to control the outer diameter size of the lens system group of the camera lens. It is beneficial to reduce the thickness in the radial direction, thereby miniaturizing the lens.

[0012] In one embodiment, the optical system satisfies the following conditional formula: 0.5 < (CT2 + CT3 + CT4 + CT5) / CT1 < 1.5; where CT1 is the thickness of the first lens on the optical axis, CT2 is the thickness of the second lens on the optical axis, CT3 is the thickness of the third lens on the optical axis, CT4 is the thickness of the fourth lens on the optical axis, and CT5 is the thickness of the fifth lens on the optical axis. By reasonably setting the value of (CT2 + CT3 + CT4 + CT5) / CT1, the resistance of the first lens to the environment can be enhanced, and appropriately configuring the thickness of each lens is conducive to the miniaturized design of the structure, avoiding the lens being too thin and affecting the lens strength, thereby affecting the manufacturing yield.

[0013] In one embodiment, the optical system satisfies the following conditional formula: 1.0 < TTL / ImgH - FFL / ImgH < 3.0; where TTL is the distance from the object side of the first lens to the imaging surface of the optical system on the optical axis, FFL is the distance from the image side of the fifth lens to the imaging surface of the optical system on the optical axis, and ImgH is half of the diagonal length of the effective pixel area of the imaging surface. By reasonably setting the value of TTL / ImgH - FFL / ImgH, while meeting the telephoto function, the size of the lens group can be effectively controlled, and the optical system has sufficient imaging size to increase the image brightness, thereby improving the imaging quality.

[0014] In one embodiment, the optical system satisfies the following conditional formula: 1.0 < T23 / T34 < 3.0; where T23 is the air separation distance between the second lens and the third lens on the optical axis, and T34 is the air separation distance between the third lens and the fourth lens on the optical axis. By reasonably setting the value of T23 / T34, sufficient space can be ensured between the third lens and the fourth lens, avoiding lens interference while making full use of the space, which is conducive to the assembly of the lens and meets the requirements of miniaturization of the optical lens.

[0015] In one embodiment, the optical system satisfies the following conditional formula: 20 < V3 < 60; where V3 is the dispersion coefficient of the third lens. By reasonably setting the dispersion coefficient of the third lens, the deflection degree of light passing through the third lens can be controlled, which is conducive to strengthening the lens aberration correction ability and balancing chromatic aberration.

[0016] In one embodiment, the optical system satisfies the following conditional formula: 20 < V5 < 60; where V5 is the dispersion coefficient of the fifth lens. By reasonably setting the dispersion coefficient of the fifth lens, the deflection degree of light passing through the fifth lens can be controlled, which is conducive to strengthening the lens aberration correction ability and balancing chromatic aberration.

[0017] In one embodiment, the optical system satisfies the following conditional formula: 0.5 < T12 + T23 + T34 + T45 < 2.5; where T12 is the air separation distance between the first lens and the second lens on the optical axis, and T45 is the air separation distance between the fourth lens and the fifth lens on the optical axis. When T12 + T23 + T34 + T45 ≤ 0.5, the space margin for the interval distribution between the lenses is too small, resulting in increased sensitivity of the optical system and being unfavorable for the assembly of each lens. When T12 + T23 + T34 + T45 ≥ 2.5, it is not conducive to the miniaturization requirements of the telephoto lens. By reasonably setting the value of T12 + T23 + T34 + T45, while ensuring the processability of the lens assembly, the lens interval distance is fully compressed, enabling the telephoto lens to achieve the characteristics of miniaturization.

[0018] In a second aspect, the present invention provides a lens module, including a lens barrel and the optical system of the first aspect, and the first lens to the fifth lens of the optical system are installed in the lens barrel. By installing each of the first lens to the fifth lens of the optical system of the first aspect in the lens module, the lens module meets the requirements of long focal length telephoto function, miniaturization, and high imaging quality.

[0019] In a third aspect, the present invention further provides an electronic device, including: a housing, an electronic photosensitive element, and the lens module of the second aspect. The lens module and the electronic photosensitive element are arranged in the housing, and the electronic photosensitive element is arranged on the imaging surface of the optical system, and is used for converting the light of the object incident on the electronic photosensitive element through the first lens to the fourth lens into an electrical signal of an image. By adding the lens module of the second aspect to the electronic device, the electronic device can achieve the shooting function of long focal length telephoto, meet the requirements of device miniaturization, and achieve the effect of high imaging quality. Description of the Drawings

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0021] Figure 1a is a schematic structural diagram of the optical system of the first embodiment;

[0022] Figure 1b is the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the first embodiment;

[0023] Figure 2a is a schematic structural diagram of the optical system of the second embodiment;

[0024] Figure 2b 7 are the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the second embodiment;

[0025] Figure 3a is a schematic structural diagram of an optical system of a third embodiment;

[0026] Figure 3b 7 are the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the third embodiment;

[0027] Figure 4a is a schematic structural diagram of an optical system of a fourth embodiment;

[0028] Figure 4b 7 are the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the fourth embodiment;

[0029] Figure 5a is a schematic structural diagram of an optical system of a fifth embodiment;

[0030] Figure 5b 7 are the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the fifth embodiment;

[0031] Figure 6a is a schematic structural diagram of an optical system of a sixth embodiment;

[0032] Figure 6b 7 are the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the sixth embodiment;

[0033] Figure 7a is a schematic structural diagram of an optical system of a seventh embodiment;

[0034] Figure 7b 1 and 2 are the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the seventh embodiment. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] The embodiment of the present invention provides a lens module, a lens barrel and the optical system, wherein the first lens to the fifth lens of the optical system are installed in the lens barrel. The lens module can be an independent lens of a digital camera, or an imaging module integrated in an electronic device such as a smart phone. By installing each lens of the first lens to the fifth lens of the optical system in the lens module, the lens module meets the requirements of long-focus telephoto function, miniaturization and high imaging quality.

[0037] The embodiment of the present invention also provides an electronic device, including: a housing, an electronic photosensitive element and a lens module of the second aspect, the lens module and the electronic photosensitive element are arranged in the housing, and the electronic photosensitive element is arranged on the imaging surface of the optical system, and is used to convert the light of the object incident on the electronic photosensitive element through the first lens to the fourth lens into an electrical signal of an image. The electronic photosensitive element can be a complementary metal oxide semiconductor (CMOS) or a charge-coupled device (CCD). The electronic device can be a smart phone, a personal digital assistant (PDA), a tablet computer, a smart watch, a drone, an e-book reader, a driving recorder, a wearable device, etc. By adding the lens module of the second aspect to the electronic device, the electronic device can realize the telephoto shooting function, meet the requirements of the miniaturization of the device, and achieve the effect of high imaging quality.

[0038] The embodiment of the present invention provides an optical system, which includes: a first lens, a second lens, a third lens, a fourth lens and a fifth lens in order from the object side to the image side along the optical axis. Among the first lens to the fifth lens, there is an air gap between any two adjacent lenses.

[0039] The optical system further comprises an aperture, which can be arranged at any position between the first lens to the fifth lens, such as between the first lens and the second lens.

[0040] The first lens has positive optical power; the second lens has optical power; the third lens has negative optical power; the fourth lens has positive optical power, and both the object side surface and the image side surface of the fourth lens are convex surfaces; the fifth lens has negative optical power;

[0041] Among them, the optical system satisfies the following relationship:

[0042] 0.2 <TD / f<0.5;

[0043] TD is the distance from the object side of the first lens to the image side of the fifth lens on the optical axis, and f is the effective focal length of the optical system.

[0044] By reasonably configuring the surface shapes and optical powers of the first to fifth lenses, a long focal length telescopic function is achieved, meeting the requirements of miniaturization and high imaging quality. When TD / f ≥ 0.5, the optical lens structure is not compact enough, resulting in an overly long lens length and being unfavorable for lens assembly. When TD / f ≤ 0.2, the optical lens length is too small, making it difficult to correct lens aberrations and resulting in poor telephoto imaging quality. By reasonably setting the value of TD / f, further reasonably distributing the optical powers of the lenses and configuring the lens shapes, while meeting the miniaturization of the lens, it is also beneficial to improve the telephoto ability of the lens.

[0045] In one embodiment, the optical system satisfies the conditional formula: -1 < f12 / f345 < -0.2; where f12 is the combined focal length of the first lens and the second lens, and f345 is the combined focal length of the third lens, the fourth lens, and the fifth lens. By controlling the magnitudes and directions of the combined focal length of the first lens and the second lens and the combined focal length of the third lens, the fourth lens, and the fifth lens, the camera lens can achieve the balance of the system spherical aberration, obtain good imaging quality in the axial field of view, and at the same time, the principal plane of the system can be far from the imaging plane, strengthening the telephoto function of the lens.

[0046] In one embodiment, the optical system satisfies the conditional formula: 0.3 < f1 / f < 0.5; where f1 is the effective focal length of the first lens. When f1 / f ≥ 0.5, the optical power of the first lens is too large, making it difficult for the negative lens of the system to correct aberrations and resulting in poor imaging quality; when f1 / f ≤ 0.3, the optical power of the first lens is unevenly distributed, leading to insufficient telephoto ability of the optical lens. Reasonably distributing the optical power of the first lens is beneficial to improving the telephoto ability of the system, reducing the system spherical aberration at the same time, and improving the clarity of the image plane.

[0047] In one embodiment, the optical system satisfies the conditional formula: -1.5 < f5 / f < -0.5; where f5 is the effective focal length of the fifth lens. By configuring the fifth lens with negative optical power and reasonably setting the value of f5 / f, the lens can achieve the telephoto function with a longer focal length through a fifth lens of a smaller size, and can achieve the effect of providing a narrower field of view and forming a larger target image.

[0048] In one embodiment, the optical system satisfies the following conditional formula: 0 < R4 / R5 < 3.0; where R4 is the curvature radius of the object side surface of the second lens, and R5 is the curvature radius of the image side surface of the second lens. When R4 / R5 ≤ 0, the surface shape of the second lens will be overly curved, with poor molding, affecting the manufacturing yield. When R4 / R5 ≥ 3, the surface shape of the second lens is too smooth, resulting in difficulty in correcting aberrations and excessive astigmatism in the outer field of view, affecting the imaging quality of the telephoto lens. By adjusting the curvature radius of the second lens, the processing feasibility of the second lens is ensured, and at the same time, the system spherical aberration and astigmatism are effectively corrected, improving the imaging quality of the camera.

[0049] In one embodiment, the optical system satisfies the following conditional formula: 1.4 < SD11 / SD52 < 2.0. Wherein, SD11 is the maximum effective semi-aperture of the object side of the first lens, and SD52 is the maximum effective semi-aperture of the image side of the fifth lens. By reasonably setting the value of SD11 / SD52, it is beneficial to control the outer diameter size of the lens system group of the camera lens. This helps to reduce the thickness in the radial direction, thereby miniaturizing the lens.

[0050] In one embodiment, the optical system satisfies the following conditional formula: 0.5 < (CT2 + CT3 + CT4 + CT5) / CT1 < 1.5; wherein, CT1 is the thickness of the first lens on the optical axis, CT2 is the thickness of the second lens on the optical axis, CT3 is the thickness of the third lens on the optical axis, CT4 is the thickness of the fourth lens on the optical axis, and CT5 is the thickness of the fifth lens on the optical axis. By reasonably setting the value of (CT2 + CT3 + CT4 + CT5) / CT1, the resistance of the first lens to the environment can be enhanced, and appropriately configuring the thickness of each lens is beneficial for the miniaturized design of the structure, avoiding the lens being too thin and affecting the lens strength, thereby affecting the manufacturing yield.

[0051] In one embodiment, the optical system satisfies the following conditional formula: 1.0 < TTL / ImgH - FFL / ImgH < 3.0; wherein, TTL is the distance from the object side of the first lens to the imaging surface of the optical system on the optical axis, FFL is the distance from the image side of the fifth lens to the imaging surface of the optical system on the optical axis, and ImgH is half of the diagonal length of the effective pixel area of the imaging surface. By reasonably setting the value of TTL / ImgH - FFL / ImgH, while satisfying the telephoto function, the size of the lens group can be effectively controlled, and the optical system has sufficient imaging size to increase the image brightness, thereby improving the imaging quality.

[0052] In one embodiment, the optical system satisfies the following conditional formula: 1.0 < T23 / T34 < 3.0; wherein, T23 is the air separation distance between the second lens and the third lens on the optical axis, and T34 is the air separation distance between the third lens and the fourth lens on the optical axis. By reasonably setting the value of T23 / T34, it can ensure that there is sufficient space between the third lens and the fourth lens. While avoiding lens interference, it can make full use of the space, which is beneficial for the assembly of the lens and meets the requirements of miniaturization of the optical lens.

[0053] In one embodiment, the optical system satisfies the following conditional formula: 20 < V3 < 60; wherein, V3 is the dispersion coefficient of the third lens. By reasonably setting the dispersion coefficient of the third lens, the deflection degree of light passing through the third lens can be controlled, which is beneficial for strengthening the lens aberration correction ability and balancing chromatic aberration.

[0054] In one embodiment, the optical system satisfies the following conditional formula: 20 < V5 < 60; where V5 is the dispersion coefficient of the fifth lens. By reasonably setting the dispersion coefficient of the fifth lens, the deflection degree of light passing through the fifth lens can be controlled, which is beneficial to strengthening the lens aberration correction ability and balancing chromatic aberration.

[0055] In one embodiment, the optical system satisfies the following conditional formula: 0.5 < T12 + T23 + T34 + T45 < 2.5; where T12 is the air separation distance between the first lens and the second lens on the optical axis, and T45 is the air separation distance between the fourth lens and the fifth lens on the optical axis. When T12 + T23 + T34 + T45 ≤ 0.5, the space margin for the interval distribution between the lenses is too small, resulting in increased sensitivity of the optical system and being unfavorable for the assembly of each lens. When T12 + T23 + T34 + T45 ≥ 2.5, it is not conducive to the miniaturization requirements of the telephoto lens. By reasonably setting the value of T12 + T23 + T34 + T45, while ensuring the lens assembly processability, the lens interval distance can be fully compressed, enabling the telephoto lens to achieve the characteristics of miniaturization.

[0056] The first embodiment

[0057] Please refer to Figure 1a and Figure 1b , the optical system of this embodiment, from the object side to the image side along the optical axis direction includes in sequence:

[0058] The first lens L1, having a positive optical power, the object side surface S1 of the first lens L1 is a convex surface, and the image side surface S2 of the first lens L1 is a convex surface.

[0059] The second lens L2, having a positive optical power, the object side surface S3 of the second lens L2 is a convex surface, and the image side surface S4 of the second lens L2 is a concave surface.

[0060] The third lens L3, having a negative optical power, the object side surface S5 of the third lens L3 is a concave surface, and the image side surface S6 of the third lens L3 is a concave surface.

[0061] The fourth lens L4, having a positive optical power, the object side surface S7 of the fourth lens L4 is a convex surface, and the image side surface S8 of the fourth lens L4 is a convex surface.

[0062] The fifth lens L5, having a negative optical power, the object side surface S9 of the fourth lens L4 is a concave surface, and the image side surface S10 of the fourth lens L4 is a concave surface.

[0063] The materials of the above-mentioned first lens L1 to fifth lens L5 are all plastic.

[0064] In addition, the optical system also includes an aperture STO, an infrared cutoff filter L6 and an imaging surface S13. The aperture STO is arranged at the object side S1 adjacent to the first lens L1 to control the amount of light entering. In other embodiments, the aperture STO can also be arranged between other two adjacent lenses. The infrared cutoff filter L6 is arranged on the image side of the fifth lens L5, which includes an object side S11 and an image side S12. The infrared cutoff filter L6 is used to filter out infrared light so that the light incident on the imaging surface S13 is visible light, and the wavelength of visible light is 380nm-780nm. The material of the infrared cutoff filter L6 is glass (Glass), and a film can be coated on the glass. The electronic photosensitive element is arranged on the image side of the optical system to receive the light of the image formed by the optical system. The surface where the image formed by the optical system is located is the imaging surface S11.

[0065] Table 1a shows the characteristics of the optical system of this embodiment, and the units of Y radius, thickness and focal length are all millimeters (mm).

[0066] Table 1a

[0067]

[0068]

[0069] Wherein, EFL is the effective focal length of the optical system, FNO is the aperture number of the optical system, FOV is the field of view 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.

[0070] In this embodiment, the object side surface and the image side surface of any lens from the first lens L1 to the fourth lens L4 are aspherical surfaces, and the surface shape x of each aspherical lens can be defined by but not limited to the following aspherical surface formula:

[0071]

[0072] Where x is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the Y radius R in Table 1a above); k is the cone coefficient; Ai is the correction coefficient of the i-th order of the aspheric surface. Table 1b gives the correction coefficients that can be used for

[0073] In the first embodiment, the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 of the aspherical mirror surfaces S1-S8 are provided.

[0074] Table 1b

[0075]

[0076]

[0077] Figure 1b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the first embodiment are shown. The longitudinal spherical aberration curve indicates the deviation of the focal point of light of different wavelengths after passing through each lens of the optical system; the astigmatism curve indicates the meridional image curvature and sagittal image curvature; and the distortion curve indicates the distortion magnitude value corresponding to different field angles. Figure 1b It can be seen that the optical system provided in the first embodiment can achieve good imaging quality.

[0078] Second embodiment

[0079] Please refer to Figure 2a and Figure 2b The optical system of this embodiment, from the object side to the image side along the optical axis direction, includes:

[0080] The first lens L1 has positive refractive power, an object-side surface S1 of the first lens L1 is a convex surface, and an image-side surface S2 of the first lens L1 is a convex surface.

[0081] The second lens L2 has negative refractive power, the object-side surface S3 of the second lens L2 is convex, and the image-side surface S4 of the second lens L2 is concave.

[0082] The third lens L3 has negative refractive power. The object-side surface S5 of the third lens L3 is a concave surface. The image-side surface S6 of the third lens L3 is a concave surface.

[0083] The fourth lens L4 has positive refractive power. The object-side surface S7 of the fourth lens L4 is a convex surface. The image-side surface S8 of the fourth lens L4 is a convex surface.

[0084] The fifth lens L5 has negative refractive power. The object-side surface S9 of the fourth lens L4 is concave, and the image-side surface S10 of the fourth lens L4 is concave.

[0085] The other structures of the second embodiment are the same as those of the first embodiment, and can be used as a reference.

[0086] Table 2a shows the characteristics of the optical system of this embodiment, and the units of Y radius, thickness and focal length are all millimeters (mm).

[0087] Table 2a

[0088]

[0089] The meanings of the parameters in Table 2a are the same as those in the first embodiment.

[0090] Table 2b gives the coefficients of the higher-order terms that can be used for each aspherical mirror surface in the second embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0091] Table 2b

[0092]

[0093]

[0094] Figure 2b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the second embodiment are shown. The longitudinal spherical aberration curve indicates the deviation of the convergence point of light of different wavelengths after passing through each lens of the optical system; the astigmatism curve indicates the meridional image curvature and sagittal image curvature; and the distortion curve indicates the distortion magnitude value corresponding to different field angles. Figure 2b It can be seen that the optical system provided in the second embodiment can achieve good imaging quality.

[0095] Third embodiment

[0096] Please refer to Figure 3a and Figure 3b The optical system of this embodiment, from the object side to the image side along the optical axis direction, includes:

[0097] The first lens L1 has positive refractive power, an object-side surface S1 of the first lens L1 is a convex surface, and an image-side surface S2 of the first lens L1 is a convex surface.

[0098] The second lens L2 has negative refractive power, the object-side surface S3 of the second lens L2 is convex, and the image-side surface S4 of the second lens L2 is concave.

[0099] The third lens L3 has negative refractive power. The object-side surface S5 of the third lens L3 is a concave surface. The image-side surface S6 of the third lens L3 is a concave surface.

[0100] The fourth lens L4 has positive refractive power. The object-side surface S7 of the fourth lens L4 is a convex surface. The image-side surface S8 of the fourth lens L4 is a convex surface.

[0101] The fifth lens L5 has negative refractive power. The object-side surface S9 of the fourth lens L4 is concave, and the image-side surface S10 of the fourth lens L4 is concave.

[0102] The other structures of the third embodiment are the same as those of the first embodiment, and can be used as a reference.

[0103] Table 3a shows a table of characteristics of the optical system of this embodiment, and the units of Y radius, thickness and focal length are all millimeters (mm).

[0104] Table 3a

[0105]

[0106]

[0107] The meanings of the parameters in Table 3a are the same as those in the first embodiment.

[0108] Table 3b gives the coefficients of the higher-order terms that can be used for each aspherical mirror surface in the third embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0109] Table 3b

[0110]

[0111] Figure 3b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the third embodiment are shown. The longitudinal spherical aberration curve indicates the deviation of the focal point of light of different wavelengths after passing through each lens of the optical system; the astigmatism curve indicates the meridional image curvature and sagittal image curvature; and the distortion curve indicates the distortion magnitude value corresponding to different field angles. Figure 3b It can be seen that the optical system provided in the third embodiment can achieve good imaging quality.

[0112] Fourth embodiment

[0113] Please refer to Figure 4a and Figure 4b The optical system of this embodiment, from the object side to the image side along the optical axis direction, includes:

[0114] The first lens L1 has positive refractive power, an object-side surface S1 of the first lens L1 is a convex surface, and an image-side surface S2 of the first lens L1 is a convex surface.

[0115] The second lens L2 has negative refractive power, the object-side surface S3 of the second lens L2 is convex, and the image-side surface S4 of the second lens L2 is concave.

[0116] The third lens L3 has negative refractive power. The object-side surface S5 of the third lens L3 is a concave surface. The image-side surface S6 of the third lens L3 is a concave surface.

[0117] The fourth lens L4 has positive refractive power. The object-side surface S7 of the fourth lens L4 is a convex surface. The image-side surface S8 of the fourth lens L4 is a convex surface.

[0118] The fifth lens L5 has negative refractive power. The object-side surface S9 of the fourth lens L4 is concave, and the image-side surface S10 of the fourth lens L4 is concave.

[0119] The other structures of the fourth embodiment are the same as those of the first embodiment, and can be referred to herein.

[0120] Table 4a shows a table of characteristics of the optical system of this embodiment, and the units of Y radius, thickness and focal length are all millimeters (mm).

[0121] Table 4a

[0122]

[0123] The meanings of the parameters in Table 4a are the same as those in the first embodiment.

[0124] Table 4b gives the coefficients of the higher-order terms that can be used for each aspherical mirror surface in the fourth embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0125] Table 4b

[0126]

[0127] Figure 4b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the fourth embodiment are shown. The longitudinal spherical aberration curve indicates the deviation of the convergence point of light of different wavelengths after passing through each lens of the optical system; the astigmatism curve indicates the meridional image curvature and sagittal image curvature; and the distortion curve indicates the distortion magnitude value corresponding to different field angles. Figure 4b It can be seen that the optical system provided in the fourth embodiment can achieve good imaging quality.

[0128] Fifth embodiment

[0129] Please refer to Figure 5a and Figure 5b The optical system of this embodiment, from the object side to the image side along the optical axis direction, includes:

[0130] The first lens L1 has positive refractive power, an object-side surface S1 of the first lens L1 is a convex surface, and an image-side surface S2 of the first lens L1 is a convex surface.

[0131] The second lens L2 has negative refractive power, the object-side surface S3 of the second lens L2 is convex, and the image-side surface S4 of the second lens L2 is concave.

[0132] The third lens L3 has negative refractive power, the object-side surface S5 of the third lens L3 is convex, and the image-side surface S6 of the third lens L3 is concave.

[0133] The fourth lens L4 has positive refractive power. The object-side surface S7 of the fourth lens L4 is a convex surface. The image-side surface S8 of the fourth lens L4 is a convex surface.

[0134] The fifth lens L5 has negative refractive power. The object-side surface S9 of the fourth lens L4 is concave. The image-side surface S10 of the fourth lens L4 at the optical axis is concave, and the image-side surface S10 at the circumference is convex.

[0135] The other structures of the fifth embodiment are the same as those of the first embodiment, and can be referred to herein.

[0136] Table 5a shows a table of characteristics of the optical system of this embodiment, and the units of Y radius, thickness and focal length are all millimeters (mm).

[0137] Table 5a

[0138]

[0139] The meanings of the parameters in Table 5a are the same as those in the first embodiment.

[0140] Table 5b gives the coefficients of the higher-order terms that can be used for each aspherical mirror surface in the fifth embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0141] Table 5b

[0142]

[0143]

[0144] Figure 5b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the fifth embodiment are shown. The longitudinal spherical aberration curve indicates the deviation of the convergence point of light of different wavelengths after passing through each lens of the optical system; the astigmatism curve indicates the meridional image curvature and sagittal image curvature; and the distortion curve indicates the distortion magnitude value corresponding to different field angles. Figure 5b It can be seen that the optical system provided in the fifth embodiment can achieve good imaging quality.

[0145] Sixth embodiment

[0146] Please refer to Figure 6a and Figure 6b The optical system of this embodiment, from the object side to the image side along the optical axis direction, includes:

[0147] The first lens L1 has positive refractive power, an object-side surface S1 of the first lens L1 is a convex surface, and an image-side surface S2 of the first lens L1 is a convex surface.

[0148] The second lens L2 has negative refractive power, the object-side surface S3 of the second lens L2 is convex, and the image-side surface S4 of the second lens L2 is concave.

[0149] The third lens L3 has negative refractive power. The object-side surface S5 of the third lens L3 is a concave surface. The image-side surface S6 of the third lens L3 is a concave surface.

[0150] The fourth lens L4 has positive refractive power. The object-side surface S7 of the fourth lens L4 is a convex surface. The image-side surface S8 of the fourth lens L4 is a convex surface.

[0151] The fifth lens L5 has negative refractive power. The object-side surface S9 of the fourth lens L4 is concave, and the image-side surface S10 of the fourth lens L4 is concave.

[0152] The other structures of the sixth embodiment are the same as those of the first embodiment, and can be referred to herein.

[0153] Table 6a shows a table of the characteristics of the optical system of this embodiment, and the units of Y radius, thickness and focal length are all millimeters (mm).

[0154] Table 6a

[0155]

[0156] The meanings of the parameters in Table 6a are the same as those in the first embodiment.

[0157] Table 6b gives the coefficients of the higher-order terms that can be used for each aspherical mirror surface in the sixth embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0158] Table 6b

[0159]

[0160]

[0161] Figure 6b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the sixth embodiment are shown. The longitudinal spherical aberration curve indicates the deviation of the convergence point of light of different wavelengths after passing through each lens of the optical system; the astigmatism curve indicates the meridional image curvature and sagittal image curvature; and the distortion curve indicates the distortion magnitude value corresponding to different field angles. Figure 6b It can be seen that the optical system provided in the sixth embodiment can achieve good imaging quality.

[0162] Seventh embodiment

[0163] Please refer to Figure 7a and Figure 7b The optical system of this embodiment, from the object side to the image side along the optical axis direction, includes:

[0164] The first lens L1 has positive refractive power, an object-side surface S1 of the first lens L1 is a convex surface, and an image-side surface S2 of the first lens L1 is a convex surface.

[0165] The second lens L2 has negative refractive power, the object-side surface S3 of the second lens L2 is convex, and the image-side surface S4 of the second lens L2 is concave.

[0166] The third lens L3 has negative refractive power, the object-side surface S5 of the third lens L3 is convex, and the image-side surface S6 of the third lens L3 is concave.

[0167] The fourth lens L4 has positive refractive power. The object-side surface S7 of the fourth lens L4 is a convex surface. The image-side surface S8 of the fourth lens L4 is a convex surface.

[0168] The fifth lens L5 has negative refractive power. The object-side surface S9 of the fourth lens L4 is concave, and the image-side surface S10 of the fourth lens L4 is concave.

[0169] The other structures of the seventh embodiment are the same as those of the first embodiment, and can be referred to herein.

[0170] Table 7a shows a table of the characteristics of the optical system of this embodiment, and the units of Y radius, thickness and focal length are all millimeters (mm).

[0171] Table 7a

[0172]

[0173]

[0174] The meanings of the parameters in Table 7a are the same as those in the first embodiment.

[0175] Table 7b gives the coefficients of the higher-order terms that can be used for each aspherical mirror surface in the seventh embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0176] Table 7b

[0177]

[0178] Figure 7b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the seventh embodiment are shown. The longitudinal spherical aberration curve indicates the deviation of the convergence point of light of different wavelengths after passing through each lens of the optical system; the astigmatism curve indicates the meridional image curvature and sagittal image curvature; and the distortion curve indicates the distortion magnitude value corresponding to different field angles. Figure 7b It can be seen that the optical system provided in the seventh embodiment can achieve good imaging quality.

[0179] Table 8 shows the values ​​of TD / f, f12 / f345, f1 / f, f5 / f, R4 / R5, SD11 / SD52, (CT2+CT3+CT4+CT5) / CT1, TTL / ImgH-FFL / ImgH, T23 / T34, V3, V5, T12+T23+T34+T45 of the optical systems of the first to seventh embodiments. It can be seen from Table 8 that each embodiment satisfies the following conditional formula: 0.2 <TD / f<0.5、-1<f12 / f345<-0.2、0.3<f1 / f<0.5、-1.5<f5 / f<-0.5、0<R4 / R5<3.0、1.4<SD 11 / SD 52<2.0、0.5<(CT 2+CT3+CT 4+CT 5) / CT 1<1.5、1.0<TTL / ImgH-FFL / ImgH<3.0、1.0<T23 / T34<3.0、20<V3<60、20<V5<60、0.5<T12+T23+T34+T45<2.5。

[0180] Table 8

[0181]

[0182] What is disclosed above is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of implementing the above-mentioned embodiment and making equivalent changes according to the claims of the present invention still fall within the scope of the invention.

Claims

1. An optical system, characterized in that: The optical system is composed of 5 lenses, which include: A first lens having positive optical power; A second lens having optical power; A third lens having negative optical power; a fourth lens having positive refractive power, wherein both the object-side surface and the image-side surface of the fourth lens are convex surfaces; a fifth lens having negative optical power, wherein the image side surface of the fifth lens is an aspherical surface; The optical system satisfies the following relationship: 0.2 <TD / f<0.5; TD is the distance from the object side surface of the first lens to the image side surface of the fifth lens on the optical axis, and f is the effective focal length of the optical system.

2. The optical system according to claim 1, wherein: The optical system satisfies the condition: -1 <f12 / f345<-0.2; Wherein, f12 is the combined focal length of the first lens and the second lens, and f345 is the combined focal length of the third lens, the fourth lens and the fifth lens.

3. The optical system according to claim 1, wherein: The optical system satisfies the condition: 0.3 <f1 / f<0.5; Wherein, f1 is the effective focal length of the first lens.

4. The optical system according to claim 1, wherein: The optical system satisfies the condition: -1.5 <f5 / f<-0.5; Wherein, f5 is the effective focal length of the fifth lens.

5. The optical system according to claim 1, wherein: The optical system satisfies the following conditional formula: 0 <R4 / R5<3.0; Wherein, R4 is the curvature radius of the object side surface of the second lens, and R5 is the curvature radius of the image side surface of the second lens.

6. The optical system according to claim 1, wherein: The optical system satisfies the following conditional formula: 1.4 <SD11 / SD52<2.0; Wherein, SD11 is the maximum effective semi-aperture of the object side of the first lens, and SD52 is the maximum effective semi-aperture of the image side of the fifth lens.

7. The optical system according to claim 1, wherein: The optical system satisfies the following conditional formula: 0.5<(CT2+CT3+CT4+CT5) / CT1<1.5; Wherein, CT1 is the thickness of the first lens on the optical axis, CT2 is the thickness of the second lens on the optical axis, CT3 is the thickness of the third lens on the optical axis, CT4 is the thickness of the fourth lens on the optical axis, and CT5 is the thickness of the fifth lens on the optical axis.

8. The optical system according to claim 1, wherein: The optical system satisfies the following conditional formula: 1.0 <TTL / ImgH-FFL / ImgH<3.0; Wherein, TTL is the distance from the object side of the first lens to the imaging surface of the optical system on the optical axis, FFL is the distance from the image side of the fifth lens to the imaging surface of the optical system on the optical axis, and ImgH is half of the diagonal length of the effective pixel area of ​​the imaging surface.

9. The optical system according to claim 1, wherein: The optical system satisfies the following conditional formula: 1.0 <T23 / T34<3.0; Wherein, T23 is the air spacing distance between the second lens and the third lens on the optical axis, and T34 is the air spacing distance between the third lens and the fourth lens on the optical axis.

10. The optical system according to claim 1, wherein: The optical system satisfies the following conditional formula: 20<V3<60； Wherein, V3 is the dispersion coefficient of the third lens.

11. The optical system according to claim 1, wherein: The optical system satisfies the following conditional formula: 20<V5<60； Wherein, V5 is the dispersion coefficient of the fifth lens.

12. The optical system according to claim 1, wherein: The optical system satisfies the following conditional formula: 0.5 <T12+T23+T34+T45<2.5; Wherein, T12 is the air spacing distance between the first lens and the second lens on the optical axis, and T45 is the air spacing distance between the fourth lens and the fifth lens on the optical axis.

13. A lens module, characterized in that: include: A lens barrel and an optical system as claimed in any one of claims 1 to 12, wherein the first lens to the fifth lens of the optical system are installed in the lens barrel.

14. An electronic device, characterized in that: include: A shell, an electronic photosensitive element and a lens module as described in claim 13, wherein the lens module and the electronic photosensitive element are arranged in the shell, and the electronic photosensitive element is arranged on the imaging surface of the optical system, and is used to convert the light of the object that passes through the first lens to the fifth lens and is incident on the electronic photosensitive element into an electrical signal of an image.

Images