Optical System, Lens Module, and Electronic Device

Abstract

The present invention provides an optical system, a lens module, and an electronic device. The optical system includes a first lens; a second lens; a third lens; a fourth lens; a fifth lens, both the object side surface and the image side surface of which are aspherical surfaces, and at least one of the object side surface and the image side surface is provided with at least one inflection point; a sixth lens, both the object side surface and the image side surface of which are aspherical surfaces, and at least one of the object side surface and the image side surface is provided with at least one inflection point. By reasonably configuring the surface types and refractive powers of the respective lenses in the present application, the optical system can simultaneously meet requirements such as high pixel count, large aperture, good image quality, compact structure, and effective reduction of internal stray light, etc.

Description

Technical Field

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

[0002] With the continuous development of manufacturing technologies for electronic products such as smart phones and tablets, the lens, which is one of the important basic parts for image data acquisition, is also developing diversely. In recent years, the development trend has gradually changed to the pursuit of large aperture, high pixel support and good imaging quality.

[0003] However, in traditional lenses, the lens spacing is relatively large, the aperture number and pixel support are difficult to meet market demands, and it is easy to generate stray light that is difficult to eliminate between the lens and the mechanism, which brings great troubles to the production of optical imaging lenses. Summary of the Invention

[0004] The purpose of the present application is to provide an optical system, a lens module and an electronic device to solve the above technical problems.

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

[0006] In a first aspect, the present application provides an optical system, which sequentially includes, from the object side to the image side along the optical axis direction: a first lens with positive refractive power, and the object side surface of the first lens is a convex surface; a second lens with negative refractive power, and the near-optical-axis part of the image side surface of the second lens is a concave surface; a third lens with refractive power, and the near-optical-axis part of the object side surface of the third lens is a convex surface; a fourth lens with refractive power, and both the object side surface and the image side surface of the fourth lens are aspherical surfaces; a fifth lens with positive refractive power, and the near-periphery part of the object side surface of the fifth lens is a concave surface, both the object side surface and the image side surface of the fifth lens are aspherical surfaces, and at least one of the object side surface and the image side surface of the fifth lens is provided with at least one inflection point; a sixth lens with negative refractive power, and the near-optical-axis part of the object side surface of the sixth lens is a convex surface, and the near-optical-axis part of the image side surface of the sixth lens is a concave surface; both the object side surface and the image side surface of the sixth lens are aspherical surfaces, and at least one of the object side surface and the image side surface of the sixth lens is provided with at least one inflection point. By reasonably configuring the surface types and refractive powers of the lenses from the first lens to the sixth lens, the optical system described in the present application can meet the requirements of high pixels, large aperture and good image quality while maintaining a compact structure and effectively reducing the influence of internal stray light.

[0007] In one embodiment, it is characterized in that the optical system satisfies the conditional formula: |SAG41| / |SAG42| < 20.0; where SAG41 is the sagitta at the maximum effective aperture of the object side surface of the fourth lens, and SAG42 is the sagitta at the maximum effective aperture of the image side surface of the fourth lens. Among them, the change in the sagitta of the fourth lens will cause a change in surface adaptability, thus being more suitable for aberration correction. When the optical system satisfies the above conditional formula, the fourth lens does not introduce an excessive surface tilt angle, which is beneficial to the processing and forming of the lens. And it can further improve the aberration correction ability of the optical system, enhance the resolution, so as to have a certain friendliness to the processing of the lens.

[0008] In one embodiment, the optical system satisfies the conditional formula: 2.2 < (CT2 + CT3 + CT4) / (CT23 + CT34) ≤ 8.5; where 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, CT23 is the axial interval distance from the image side surface of the second lens to the object side surface of the third lens, and CT34 is the axial interval distance from the image side surface of the third lens to the object side surface of the fourth lens. When the optical system satisfies the above conditional formula, the average refractive indices of the second lens, the third lens, and the fourth lens and the air gap are reasonably adjusted, the center thickness and edge thickness of the second lens, the third lens, and the fourth lens are increased, and the air gap between the lenses is compressed, which can improve the overall compactness of the lens group to a certain extent, and is beneficial to reducing the deflection angle of light during refraction, thereby reducing the tolerance sensitivity.

[0009] In one embodiment, the optical system satisfies the conditional formula: 0.35 < f / |f3| + f / |f4| < 0.8; where f is the effective focal length of the optical system, f3 is the effective focal length of the third lens, and f4 is the effective focal length of the fourth lens. Among them, the refractive power changes of the third lens and the fourth lens enable the distortion and coma generated by the front lens group to be significantly balanced. The third lens and the fourth lens themselves do not introduce large aberrations, so the surface shapes of the third lens and the fourth lens can be flexibly set to improve the resolution of the optical system; when the optical system satisfies the above conditional formula, the refractive power distribution of the third lens and the fourth lens is relatively reasonable, the deflection angle of the marginal rays can be well controlled, and at the same time, it is helpful to improve the image plane illuminance and increase the stability of the optical system.

[0010] In one embodiment, the optical system satisfies the conditional formula: |SAG61 / CT6| ≤ 1.8; where SAG61 is the sagitta at the effective aperture of the object side surface of the sixth lens, and CT6 is the thickness of the sixth lens on the optical axis. When the optical system satisfies the above conditional formula, the change in the sagitta and surface shape of the sixth lens provides different possibilities for the refractive power distribution in the direction perpendicular to the optical axis near the image plane, and also enables better guiding of light rays, avoiding too large an incident angle of the light rays onto the image plane, thus well matching the high-pixel photosensitive chip. At the same time, the sixth lens can effectively balance the aberration generated by the front lens group, which is more conducive to improving the image quality of the system.

[0011] In one embodiment, the optical system satisfies the conditional formula: 0.2 < ||R51| - |R52|| / (|R51| + |R52|) ≤ 0.8; where R51 is the radius of curvature of the object side surface of the fifth lens on the optical axis, and R52 is the radius of curvature of the image side surface of the fifth lens on the optical axis. When the optical system satisfies the above conditional formula, the fifth lens contains at least one inflection point and is an aspherical surface, and can compress the lens thickness, thereby effectively improving the aberration generated by the front lens group and further improving the resolution.

[0012] In one embodiment, the optical system satisfies the conditional formula: f123 / |f56| ≤ 0.36; where f123 is the total effective focal length of the first lens, the second lens, and the third lens, and f56 is the total effective focal length of the fifth lens and the sixth lens. Among them, the rationality of the thickness and gap is directly related to the difficulty of lens forming and manufacturing. When the optical system satisfies the above conditional formula, the middle thickness and edge thickness of the first lens, the second lens, and the third lens can be kept appropriate, and the refractive power distribution is reasonable, thereby effectively improving the structure, rationality, and compactness of the lens, which is beneficial to the compression of the overall length of the optical system and the balance of the image quality, and can reduce the difficulty of lens arrangement and assembly.

[0013] In one embodiment, the optical system satisfies the conditional formula: 0.60 mm < (CT1 + BF) / FNO ≤ 0.85 mm; where CT1 is the thickness of the first lens on the optical axis, BF is the axial distance from the farthest point on the image side surface of the sixth lens to the image plane, and FNO is the aperture number of the optical system. The reasonable setting of BF can better meet the matching of the lens optical system and the chip; when the optical system satisfies the above conditional formula, the first lens can maintain good thickness and surface shape at a small aperture number, which helps to reduce the risk of lens forming. In addition, it also provides support for the increase of the field of view angle.

[0014] In one embodiment, the optical system satisfies the conditional formula: 6.1 < |f3| / n3 < 22.7; where f3 is the effective focal length of the third lens, and n3 is the refractive index of the material of the third lens at a wavelength of 587.6 nm. When the optical system satisfies the above conditional formula, the refractive power of the third lens and other lenses can be reasonably distributed, so that the optical system supports aberration balance and image quality improvement under different materials, and also makes it easy to compress the air gap between the second lens, the third lens, and the fourth lens, thereby improving the compactness of the optical system and avoiding the influence of stray light.

[0015] In one embodiment, the optical system satisfies the conditional formula: ET34 / ImgH ≤ 0.12; where ET34 is the axial distance from the maximum effective aperture of the image side of the third lens to the maximum effective aperture of the object side of the fourth lens, and ImgH is half of the diagonal length of the effective imaging area on the imaging surface of the optical system. Among them, ImgH determines the size of the electronic photosensitive chip. The larger ImgH is, the larger the maximum size of the supported electronic photosensitive chip is. When the optical system satisfies the above conditional formula, the optical system can support an electronic photosensitive chip with a higher pixel count; at the same time, the effective aperture distance between the third lens and the fourth lens can be effectively controlled, so that the deflection angle of the marginal rays is smaller, which is beneficial to reducing the tolerance sensitivity of the optical system and further improving the marginal field performance.

[0016] In a second aspect, the present application further provides a lens module, including a lens barrel, an electronic photosensitive element, and the optical system according to any one of the embodiments of the first aspect. The first lens to the sixth lens of the optical system are installed in the lens barrel, and the electronic photosensitive element is arranged on the image side 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 sixth lens into an electrical signal of an image. By installing the above optical system in the lens module, the lens module can meet the requirements of high pixels, large aperture, and good image quality while maintaining a compact structure and effectively reducing the influence of internal stray light.

[0017] In a third aspect, the present application further provides an electronic device, including a housing and the lens module according to the second aspect, and the lens module is arranged in the housing. By providing the lens module according to the second aspect in the electronic device, the electronic device can meet the requirements of high pixels, large aperture, and good image quality while maintaining a compact structure and effectively reducing the influence of internal stray light. Description of the Drawings

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0019] Figure 1a is a schematic structural diagram of the optical system of the first embodiment;

[0020] Figure 1b is the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the first embodiment;

[0021] Figure 2a is a schematic structural diagram of the optical system of the second embodiment;

[0022] Figure 2b is the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the second embodiment;

[0023] Figure 3a is a schematic structural diagram of the optical system of the third embodiment;

[0024] Figure 3b is the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the third embodiment;

[0025] Figure 4a is a schematic structural diagram of the optical system of the fourth embodiment;

[0026] Figure 4b is the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the fourth embodiment;

[0027] Figure 5a is a schematic structural diagram of the optical system of the fifth embodiment;

[0028] Figure 5b is the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the fifth embodiment;

[0029] Figure 6a is a schematic structural diagram of the optical system of the sixth embodiment;

[0030] Figure 6b is the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the sixth embodiment.

[0031] Figure 7a is a schematic structural diagram of the optical system of the seventh embodiment;

[0032] Figure 7b is the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the seventh embodiment. Detailed implementation manners

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are only a part rather than all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0034] An embodiment of the present application provides a lens module, which includes a lens barrel, an electronic photosensitive element, and an optical system provided by the embodiment of the present invention. The first lens to the sixth lens of the optical system are installed in the lens barrel, and the electronic photosensitive element is arranged on the image side of the optical system for converting the light of an object incident on the electronic photosensitive element through the first lens to the sixth lens 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). The lens module may be an independent lens of a digital camera or an imaging module integrated on an electronic device such as a smart phone. By installing the first lens to the sixth lens of the optical system in the lens module and reasonably configuring the surface shapes and refractive powers of the lenses of the first lens to the sixth lens, the lens module provided by the embodiment of the present application can meet the requirements of high pixel, large aperture, and good image quality while maintaining a compact structure and effectively reducing the influence of internal stray light.

[0035] An embodiment of the present application provides an electronic device, which includes a housing and the lens module provided by the embodiment of the present application. The lens module and the electronic photosensitive element are arranged in the housing. The electronic device may 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 arranging the lens module in the second aspect in the electronic device, the electronic device can meet the requirements of high pixel, large aperture, and good image quality while maintaining a compact structure and effectively reducing the influence of internal stray light.

[0036] An embodiment of the present application provides an optical system, which sequentially includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens from the object side to the image side along the optical axis direction. An air gap may exist between any two adjacent lenses among the first lens to the sixth lens.

[0037] Specifically, the specific shapes and structures of the six lenses are as follows:

[0038] The first lens has a positive refractive power, and the object side surface of the first lens is convex; the second lens has a negative refractive power, and the image side surface of the second lens near the optical axis is concave; the third lens has a refractive power, and the object side surface of the third lens near the optical axis is convex; the fourth lens has a refractive power, and both the object side surface and the image side surface of the fourth lens are aspherical surfaces; the fifth lens has a positive refractive power, the object side surface of the fifth lens near the circumference is concave, both the object side surface and the image side surface of the fifth lens are aspherical surfaces, and at least one of the object side surface and the image side surface of the fifth lens is provided with at least one inflection point; the sixth lens has a negative refractive power, the object side surface of the sixth lens near the optical axis is convex, and the image side surface of the sixth lens near the optical axis is concave; both the object side surface and the image side surface of the sixth lens are aspherical surfaces, and at least one of the object side surface and the image side surface of the sixth lens is provided with at least one inflection point. At the same time, by reasonably configuring the surface shapes and refractive powers of the first lens to the sixth lens, the optical system provided by the embodiment of the present application can meet the requirements of high pixels, large aperture and good image quality while maintaining a compact structure and effectively reducing the influence of internal stray light.

[0039] In an embodiment, the optical system satisfies the conditional formula: |SAG41| / |SAG42| < 20.0; where SAG41 is the sagitta at the maximum effective aperture of the object side surface of the fourth lens, and SAG42 is the sagitta at the maximum effective aperture of the image side surface of the fourth lens. Among them, the change in the sagitta of the fourth lens will cause an adaptive change in the surface shape, which is more suitable for the correction of aberrations. When the optical system satisfies the above conditional formula, the fourth lens does not introduce an excessive surface shape inclination angle, which is beneficial to the processing and forming of the lens. And it can further improve the aberration correction ability of the optical system, enhance the resolving power, so as to have a certain friendliness to the processing of the lens.

[0040] In an embodiment, the optical system satisfies the conditional formula: 2.2 < (CT2 + CT3 + CT4) / (CT23 + CT34) ≤ 8.5; where 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, CT23 is the interval distance on the optical axis from the image side surface of the second lens to the object side surface of the third lens, and CT34 is the interval distance on the optical axis from the image side surface of the third lens to the object side surface of the fourth lens. When the optical system satisfies the above conditional formula, by reasonably adjusting the average refractive index of the second lens, the third lens and the fourth lens and the air gap, increasing the center thickness and edge thickness of the second lens, the third lens and the fourth lens, and compressing the air gap between the lenses, the overall compactness of the lens group can be improved to a certain extent, which is beneficial to reducing the deflection angle of light during refraction, thereby reducing the tolerance sensitivity.

[0041] In one embodiment, the optical system satisfies the conditional formula: 0.35 < f / |f3| + f / |f4| < 0.8; where f is the effective focal length of the optical system, f3 is the effective focal length of the third lens, and f4 is the effective focal length of the fourth lens. Among them, the refractive power of the third lens and the fourth lens changes, so that the distortion and coma generated by the front lens group can be significantly balanced. The third lens and the fourth lens themselves do not introduce large aberrations. Therefore, the surface shapes of the third lens and the fourth lens can be flexibly set to improve the resolution of the optical system. When the optical system satisfies the above conditional formula, the refractive power distribution of the third lens and the fourth lens is relatively reasonable, the deflection angle of the marginal rays can be well controlled, and at the same time, it helps to improve the image plane illuminance and increase the stability of the optical system.

[0042] In one embodiment, the optical system satisfies the conditional formula: |SAG61 / CT6| ≤ 1.8; where SAG61 is the sag of the object side effective aperture of the sixth lens, and CT6 is the thickness of the sixth lens on the optical axis. When the optical system satisfies the above conditional formula, the change of the sag and surface shape of the sixth lens provides different possibilities for the refractive power distribution in the direction perpendicular to the optical axis near the image plane, and also enables better guiding of light rays to avoid too large an incident angle of the light rays incident on the image plane, thus well matching the high-pixel photosensitive chip. At the same time, the sixth lens can effectively balance the aberrations generated by the front lens group, which is more conducive to the improvement of the system image quality.

[0043] In one embodiment, the optical system satisfies the conditional formula: 0.2 < ||R51| - |R52|| / (|R51| + |R52|) ≤ 0.8; where R51 is the radius of curvature of the object side of the fifth lens on the optical axis, and R52 is the radius of curvature of the image side of the fifth lens on the optical axis. When the optical system satisfies the above conditional formula, the fifth lens contains at least one inflection point and is an aspherical surface, and at the same time, the lens thickness can be compressed, thereby effectively improving the aberrations generated by the front lens group and further improving the resolution.

[0044] In one embodiment, the optical system satisfies the conditional formula: f123 / |f56| ≤ 0.36; where f123 is the total effective focal length of the first lens, the second lens, and the third lens, and f56 is the total effective focal length of the fifth lens and the sixth lens. Among them, the rationality of the thickness and the gap is directly related to the difficulty of lens forming and manufacturing. When the optical system satisfies the above conditional formula, the middle thickness and edge thickness of the first lens, the second lens, and the third lens can be kept appropriate, and the refractive power distribution is reasonable, thereby effectively improving the structure, rationality, and compactness of the lens, which is beneficial to the compression of the overall length of the optical system and the balance of the image quality, and can reduce the difficulty of lens arrangement and assembly.

[0045] In one embodiment, the optical system satisfies the conditional formula: 0.60 mm < (CT1 + BF) / FNO ≤ 0.85 mm; where CT1 is the thickness of the first lens on the optical axis, BF is the axial distance from the farthest point on the image side of the sixth lens to the image plane, and FNO is the f-number of the optical system. A reasonable setting of BF can better meet the matching between the lens optical system and the chip; when the optical system satisfies the above conditional formula, the first lens can maintain good thickness and surface shape at a small f-number, which helps to reduce the risk of lens forming. In addition, it also provides support for increasing the field of view angle.

[0046] In one embodiment, the optical system satisfies the conditional formula: 6.1 < |f3| / n3 < 22.7; where f3 is the effective focal length of the third lens, and n3 is the refractive index of the material of the third lens at a wavelength of 587.6 nm. When the optical system satisfies the above conditional formula, the refractive powers of the third lens and other lenses can be reasonably distributed, enabling the optical system to support aberration balance and image quality improvement under different materials. It also makes it easier to compress the air gaps between the second lens, the third lens, and the fourth lens, thereby improving the compactness of the optical system and avoiding the influence of stray light.

[0047] In one embodiment, the optical system satisfies the conditional formula: ET34 / ImgH ≤ 0.12; where ET34 is the axial distance from the maximum effective aperture of the image side of the third lens to the maximum effective aperture of the object side of the fourth lens, and ImgH is half of the diagonal length of the effective imaging area on the imaging plane of the optical system. Among them, ImgH determines the size of the electronic photosensitive chip. The larger ImgH is, the larger the maximum size of the supported electronic photosensitive chip is. When the optical system satisfies the above conditional formula, the optical system can support an electronic photosensitive chip with a higher pixel count; at the same time, the effective aperture distance between the third lens and the fourth lens can be effectively controlled, resulting in a smaller deflection angle of the marginal rays, which is beneficial to reducing the tolerance sensitivity of the optical system and further improving the marginal field performance.

[0048] The first embodiment

[0049] Please refer to Figure 1a and Figure 1b , the optical system of this embodiment sequentially includes, from the object side to the image side along the optical axis direction:

[0050] The first lens L1, having a positive refractive power, with the object side surface S1 of the first lens L1 being convex near the optical axis and near the circumference, and the image side surface S2 of the first lens L1 being convex near the optical axis and near the circumference;

[0051] The second lens L2, having a negative refractive power, with the object side surface S3 of the second lens L2 being concave near the optical axis and near the circumference, the image side surface S4 of the second lens L2 being concave near the optical axis, and the image side surface S4 being convex near the circumference;

[0052] The third lens L3 has a negative refractive power. The object side surface S5 of the third lens L3 is convex near the optical axis and concave near the circumference. The image side surface S6 of the third lens L3 is concave near the optical axis and near the circumference.

[0053] The fourth lens L4 has a positive refractive power. The object side surface S7 of the fourth lens L4 is convex near the optical axis and near the circumference. The image side surface S8 of the fourth lens L4 is concave near the optical axis and near the circumference.

[0054] The fifth lens L5 has a positive refractive power. The object side surface S9 of the fifth lens L5 is concave near the optical axis and near the circumference. The image side surface S10 of the fifth lens L5 is convex near the optical axis and near the circumference.

[0055] The sixth lens L6 has a negative refractive power. The object side surface S11 of the sixth lens L6 is convex near the optical axis and near the circumference. The image side surface S12 of the sixth lens L6 is concave near the optical axis and near the circumference.

[0056] The materials of the above-mentioned first lens L1 to sixth lens L6 are all plastics.

[0057] In addition, the optical system further includes a diaphragm STO, an infrared filter L7, and an image plane S15. The diaphragm STO is disposed on the side of the first lens L1 away from the second lens L2 for controlling the amount of incident light. In other embodiments, the diaphragm STO can also be disposed between two adjacent lenses or on other lenses. The infrared filter L7 is disposed on the image side of the sixth lens L6 and includes an object side surface S13 and an image side surface S14. The infrared filter L7 is used to filter out infrared light so that the light incident on the image plane S15 is visible light, and the wavelength of the visible light is 380nm - 780nm. The material of the infrared filter L7 is glass and can be coated with a film on the glass. The image plane S15 is the plane where the image of the light of the object to be photographed is formed after passing through the optical system.

[0058] Table 1a shows a table of the characteristics of the optical system of this embodiment, where the data is obtained using light with a wavelength of 587.6nm, and the units of the Y radius, thickness, and focal length are all millimeters (mm).

[0059] Table 1a

[0060]

[0061] Wherein, f is the effective focal length of the optical system, FNO is the f-number of the optical system, FOV is the field of view angle of the optical system, and TTL is the distance from the object side surface of the first lens to the imaging surface of the optical system on the optical axis.

[0062] In this embodiment, the object side and the image side of any one of the first lens L1 to the sixth lens L6 are aspherical surfaces. The surface profile x of each aspherical lens can be defined by, but not limited to, the following aspherical formula:

[0063]

[0064] Where x is the sagitta, the distance from the vertex of the aspherical surface to the aspherical surface along the optical axis at a position with a height of h; c is the paraxial curvature of the aspherical 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 conic coefficient; Ai is the correction coefficient of the i-th order of the aspherical surface. Table 1b gives the higher-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for each of the aspherical mirrors S1 - S16 in the first embodiment.

[0065] Table 1b

[0066]

[0067] Figure 1b Shows the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system of the first embodiment. Among them, the longitudinal spherical aberration curve represents the deviation of the convergence points of light rays of different wavelengths after passing through each lens of the optical system; the astigmatism curve represents the meridional image plane curvature and sagittal image plane curvature; the distortion curve represents the distortion magnitude values corresponding to different field angles. According to Figure 1b it can be seen that the optical system given in the first embodiment can achieve good imaging quality.

[0068] Second Embodiment

[0069] Please refer to Figure 2a and Figure 2b , the optical system of this embodiment includes, in order from the object side to the image side along the optical axis:

[0070] The first lens L1, having a positive refractive power. The object side S1 of the first lens L1 is convex near the optical axis and near the circumference, and the image side S2 of the first lens L1 is concave near the optical axis and convex near the circumference;

[0071] The second lens L2, having a negative refractive power. The object side S3 of the second lens L2 is convex near the optical axis and concave near the circumference, and the image side S4 of the second lens L2 is concave near the optical axis and near the circumference;

[0072] The third lens L3, having a negative refractive power. The object side S5 of the third lens L3 is convex near the optical axis and near the circumference, and the image side S6 of the third lens L3 is concave near the optical axis and near the circumference;

[0073] The fourth lens L4 has a positive refractive power. The area near the optical axis and the area near the circumference of the object side surface S7 of the fourth lens L4 are convex surfaces, the area near the optical axis of the image side surface S8 of the fourth lens L4 is a concave surface, and the area near the circumference of the image side surface S8 is a convex surface;

[0074] The fifth lens L5 has a positive refractive power. The area near the optical axis of the object side surface S9 of the fifth lens L5 is a convex surface, the area near the circumference of the object side surface S9 is a concave surface, and the areas near the optical axis and the circumference of the image side surface S10 of the fifth lens L5 are convex surfaces;

[0075] The sixth lens L6 has a negative refractive power. The area near the optical axis of the object side surface S11 of the sixth lens L6 is a convex surface, the area near the circumference of the object side surface S11 is a concave surface, the area near the optical axis of the image side surface S12 of the sixth lens L6 is a concave surface, and the area near the circumference of the image side surface S12 is a convex surface.

[0076] The other structures of the second embodiment are the same as those of the first embodiment, and can be referred to accordingly.

[0077] Table 2a shows a table of the characteristics of the optical system of this embodiment, where the data is obtained using light with a wavelength of 587.6 nm. The units of the Y radius, thickness, and focal length are all millimeters (mm).

[0078] Table 2a

[0079]

[0080]

[0081] Among them, the meanings of the parameters in Table 2a are the same as those of the parameters in the first embodiment.

[0082] Table 2b gives the higher-order term coefficients of the aspherical mirror surfaces that can be used in the second embodiment. Among them, the aspherical surface types can be defined by the formulas given in the first embodiment.

[0083] Table 2b

[0084]

[0085] Figure 2b Shows the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system of the second embodiment. According to Figure 2b It can be seen that the optical system given in the second embodiment can achieve good imaging quality.

[0086] Third Embodiment

[0087] Please refer to Figure 3a and Figure 3b For the optical system of this embodiment, along the optical axis direction from the object side to the image side, it sequentially includes:

[0088] The first lens L1 has a positive refractive power. The object side surface S1 of the first lens L1 is convex near the optical axis and near the circumference, and the image side surface S2 of the first lens L1 is concave near the optical axis and near the circumference.

[0089] The second lens L2 has a negative refractive power. The object side surface S3 of the second lens L2 is convex near the optical axis and concave near the circumference, and the image side surface S4 of the second lens L2 is concave near the optical axis and near the circumference.

[0090] The third lens L3 has a positive refractive power. The object side surface S5 of the third lens L3 is convex near the optical axis and near the circumference, and the image side surface S6 of the third lens L3 is concave near the optical axis and near the circumference.

[0091] The fourth lens L4 has a positive refractive power. The object side surface S7 of the fourth lens L4 is convex near the optical axis and concave near the circumference, and the image side surface S8 of the fourth lens L4 is convex near the optical axis and near the circumference.

[0092] The fifth lens L5 has a positive refractive power. The object side surface S9 of the fifth lens L5 is convex near the optical axis and concave near the circumference, and the image side surface S10 of the fifth lens L5 is convex near the optical axis and concave near the circumference.

[0093] The sixth lens L6 has a negative refractive power. The object side surface S11 of the sixth lens L6 is convex near the optical axis and concave near the circumference, and the image side surface S12 of the sixth lens L6 is concave near the optical axis and convex near the circumference.

[0094] The other structures of the third embodiment are the same as those of the first embodiment, and can be referred to.

[0095] Table 3a shows a table of the characteristics of the optical system of this embodiment, where the data is obtained with light of a wavelength of 587.6 nm, and the units of the Y radius, thickness, and focal length are all millimeters (mm).

[0096] Table 3a

[0097]

[0098]

[0099] Among them, the meanings of the parameters in Table 3a are the same as those of the parameters in the first embodiment.

[0100] Table 3b gives the higher-order term coefficients of the aspherical mirror surfaces that can be used in the third embodiment. Among them, the aspherical surface types can be defined by the formulas given in the first embodiment.

[0101] Table 3b

[0102]

[0103] Figure 3b The longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system of the third embodiment are shown. According to Figure 3b it can be seen that the optical system given in the third embodiment can achieve good imaging quality.

[0104] Fourth Embodiment

[0105] Please refer to Figure 4a and Figure 4b , the optical system of this embodiment sequentially includes, from the object side to the image side along the optical axis direction:

[0106] The first lens L1 has a positive refractive power. The object side surface S1 of the first lens L1 is convex near the optical axis and near the circumference, the image side surface S2 of the first lens L1 is concave near the optical axis, and the image side surface S2 is convex near the circumference;

[0107] The second lens L2 has a negative refractive power. The object side surface S3 of the second lens L2 is convex near the optical axis and concave near the circumference, and the image side surface S4 of the second lens L2 is concave near the optical axis and near the circumference;

[0108] The third lens L3 has a positive refractive power. The object side surface S5 of the third lens L3 is convex near the optical axis and near the circumference, and the image side surface S6 of the third lens L3 is convex near the optical axis and near the circumference;

[0109] The fourth lens L4 has a negative refractive power. The object side surface S7 of the fourth lens L4 is convex near the optical axis and concave near the circumference, and the image side surface S8 of the fourth lens L4 is concave near the optical axis and near the circumference;

[0110] The fifth lens L5 has a positive refractive power. The object side surface S9 of the fifth lens L5 is convex near the optical axis and concave near the circumference, the image side surface S10 of the fifth lens L5 is concave near the optical axis, and the image side surface S10 is convex near the circumference;

[0111] The sixth lens L6 has a negative refractive power. The object side surface S11 of the sixth lens L6 is convex near the optical axis and concave near the circumference, and the image side surface S12 of the sixth lens L6 is concave near the optical axis and convex near the circumference.

[0112] The other structures of the fourth embodiment are the same as those of the first embodiment, and can be referred to.

[0113] Table 4a shows a table of the characteristics of the optical system of this embodiment, where the data is obtained with light of a wavelength of 587.6 nm, and the units of the Y radius, thickness, and focal length are all millimeters (mm).

[0114] Table 4a

[0115]

[0116]

[0117] Among them, the meanings of the parameters in Table 4a are the same as those of the parameters in the first embodiment.

[0118] Table 4b gives the higher-order term coefficients that can be used for each aspherical mirror surface in the fourth embodiment. Among them, each aspherical surface type can be defined by the formula given in the first embodiment.

[0119] Table 4b

[0120]

[0121] Figure 4b shows the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system of the fourth embodiment. According to Figure 4b it can be known that the optical system given in the fourth embodiment can achieve good imaging quality.

[0122] The fifth embodiment

[0123] Please refer to Figure 5a and Figure 5b , the optical system of this embodiment sequentially includes, from the object side to the image side along the optical axis direction:

[0124] The first lens L1, which has a positive refractive power. The object side surface S1 of the first lens L1 is convex near the optical axis and near the circumference, and the image side surface S2 of the first lens L1 is concave near the optical axis and near the circumference;

[0125] The second lens L2, which has a negative refractive power. The object side surface S3 of the second lens L2 is convex near the optical axis and concave near the circumference, and the image side surface S4 of the second lens L2 is concave near the optical axis and convex near the circumference;

[0126] The third lens L3, which has a positive refractive power. The object side surface S5 of the third lens L3 is convex near the optical axis and near the circumference, and the image side surface S6 of the third lens L3 is convex near the optical axis and concave near the circumference;

[0127] The fourth lens L4, which has a negative refractive power. The object side surface S7 of the fourth lens L4 is concave near the optical axis and near the circumference, and the image side surface S8 of the fourth lens L4 is convex near the optical axis and concave near the circumference;

[0128] The fifth lens L5, which has a positive refractive power. The object side surface S9 of the fifth lens L5 is convex near the optical axis and concave near the circumference, and the image side surface S10 of the fifth lens L5 is convex near the optical axis and near the circumference;

[0129] The sixth lens L6 has a negative refractive power. The object side surface S11 of the sixth lens L6 is convex near the optical axis and concave near the circumference. The image side surface S12 of the sixth lens L6 is concave near the optical axis and convex near the circumference.

[0130] The other structures of the fifth embodiment are the same as those of the first embodiment, and can be referred to.

[0131] Table 5a shows a table of the characteristics of the optical system of this embodiment, and the data therein are obtained with light rays of a wavelength of 587.6 nm. The units of the Y radius, thickness, and focal length are all millimeters (mm).

[0132] Table 5a

[0133]

[0134]

[0135] Among them, the meanings of the parameters in Table 5a are the same as those of the parameters in the first embodiment.

[0136] Table 5b gives the high-order term coefficients of the aspherical mirror surfaces that can be used in the fifth embodiment. Among them, the aspherical surface types can be defined by the formulas given in the first embodiment.

[0137] Table 5b

[0138]

[0139] Figure 5b Shows the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system of the fifth embodiment. According to Figure 5b It can be seen that the optical system given in the fifth embodiment can achieve good imaging quality.

[0140] Sixth embodiment

[0141] Please refer to Figure 6a and Figure 6b , the optical system of this embodiment sequentially includes, from the object side to the image side along the optical axis direction:

[0142] The first lens L1 has a positive refractive power. The object side surface S1 of the first lens L1 is convex near the optical axis and near the circumference. The image side surface S2 of the first lens L1 is concave near the optical axis and convex near the circumference.

[0143] The second lens L2 has a negative refractive power. The object side surface S3 of the second lens L2 is convex near the optical axis and near the circumference. The image side surface S4 of the second lens L2 is concave near the optical axis and near the circumference.

[0144] The third lens L3 has a positive refractive power. The object side surface S5 of the third lens L3 is convex near the optical axis and concave near the circumference. The image side surface S6 of the third lens L3 is concave near the optical axis and convex near the circumference.

[0145] The fourth lens L4 has a positive refractive power. The object side surface S7 of the fourth lens L4 is concave both near the optical axis and near the circumference. The image side surface S8 of the fourth lens L4 is convex both near the optical axis and near the circumference.

[0146] The fifth lens L5 has a positive refractive power. The object side surface S9 of the fifth lens L5 is convex near the optical axis and concave near the circumference. The image side surface S10 of the fifth lens L5 is concave near the optical axis and convex near the circumference.

[0147] The sixth lens L6 has a negative refractive power. The object side surface S11 of the sixth lens L6 is convex near the optical axis and concave near the circumference. The image side surface S12 of the sixth lens L6 is concave near the optical axis and convex near the circumference.

[0148] The other structures of the sixth embodiment are the same as those of the first embodiment, and can be referred to.

[0149] Table 6a shows a table of the characteristics of the optical system of this embodiment, where the data are obtained with light of a wavelength of 587.6 nm. The units of the Y radius, thickness, and focal length are all millimeters (mm).

[0150] Table 6a

[0151]

[0152]

[0153] Among them, the meanings of the parameters in Table 6a are the same as those of the parameters in the first embodiment.

[0154] Table 6b gives the higher-order term coefficients of the aspherical mirror surfaces that can be used in the sixth embodiment. Among them, the aspherical surface types can be defined by the formulas given in the first embodiment.

[0155] Table 6b

[0156]

[0157] Figure 6b Shows the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system of the sixth embodiment. According to Figure 6b It can be seen that the optical system given in the sixth embodiment can achieve good imaging quality.

[0158] Seventh embodiment

[0159] Please refer to Figure 7a and Figure 7b For the optical system of this embodiment, along the optical axis direction from the object side to the image side, it sequentially includes:

[0160] The first lens L1 has a positive refractive power. At the near-optical axis and near-circumference of the object side surface S1 of the first lens L1, it is convex, and at the near-optical axis and near-circumference of the image side surface S2 of the first lens L1, it is concave;

[0161] The second lens L2 has a negative refractive power. At the near-optical axis of the object side surface S3 of the second lens L2, it is convex, at the near-circumference of the object side surface S3, it is concave, and at the near-optical axis and near-circumference of the image side surface S4 of the second lens L2, it is concave;

[0162] The third lens L3 has a positive refractive power. At the near-optical axis and near-circumference of the object side surface S5 of the third lens L3, it is convex. At the near-optical axis of the image side surface S6 of the third lens L3, it is concave, and at the near-circumference of the image side surface S6, it is convex;

[0163] The fourth lens L4 has a positive refractive power. At the near-optical axis of the object side surface S7 of the fourth lens L4, it is convex, at the near-circumference of the object side surface S7, it is concave, and at the near-optical axis and near-circumference of the image side surface S8 of the fourth lens L4, it is concave;

[0164] The fifth lens L5 has a positive refractive power. At the near-optical axis of the object side surface S9 of the fifth lens L5, it is convex, at the near-circumference of the object side surface S9, it is concave, and at the near-optical axis and near-circumference of the image side surface S10 of the fifth lens L5, it is convex;

[0165] The sixth lens L6 has a negative refractive power. At the near-optical axis of the object side surface S11 of the sixth lens L6, it is convex, at the near-circumference of the object side surface S11, it is concave. At the near-optical axis of the image side surface S12 of the sixth lens L6, it is concave, and at the near-circumference of the image side surface S12, it is convex;

[0166] The other structures of the seventh embodiment are the same as those of the first embodiment, and can be referred to.

[0167] Table 7a shows a table of the characteristics of the optical system of this embodiment, where the data is obtained with light of a wavelength of 587.6 nm. The units of the Y radius, thickness, and focal length are all millimeters (mm).

[0168] Table 7a

[0169]

[0170]

[0171] Among them, the meanings of the parameters in Table 7a are the same as those of the parameters in the first embodiment.

[0172] Table 7b gives the higher-order term coefficients for each aspherical mirror surface that can be used in the seventh embodiment, where each aspherical surface profile can be defined by the formula given in the first embodiment.

[0173] Table 7b

[0174]

[0175] Figure 7b shows the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system of the seventh embodiment. According to Figure 7b it can be seen that the optical system given in the seventh embodiment can achieve good imaging quality.

[0176] Table 8 shows the values of |SAG41| / |SAG42|, (CT2 + CT3 + CT4) / (CT23 + CT34), f / |f3| + f / |f4|, |SAG61 / CT6|, ||R51| - |R52|| / ||R51| + |R52||, f123 / |f56|, (CT1 + BF) / FNO, |f3| / n3, and ET34 / ImgH for the optical systems of the first to seventh embodiments.

[0177] Table 8

[0178] |SAG41| / |SAG42| (CT2 + CT3 + CT4) / (CT23 + CT34) f / |f3| + f / |f4| |SAG61 / CT6| |f3| / n3 First Embodiment 1.14 3.75 0.62 0.11 22.65 Second Embodiment 19.75 5.80 0.62 0.67 17.05 Third Embodiment 0.06 4.52 0.56 1.50 14.70 Fourth Embodiment 1.31 2.21 0.56 1.4 6.29 Fifth Embodiment 1.16 5.59 0.63 0.22 6.15 Sixth Embodiment 0.52 2.50 0.39 0.68 7.95 Seventh Embodiment 0.76 8.50 0.77 1.80 8.50 f123 / |f56| ||R51| - |R52|| / ||R51| + |R52|| (CT1 + BF) / FNO ET34 / ImgH First Embodiment 0.12 0.31 0.78 0.12 Second Embodiment 0.36 0.59 0.83 0.03 Third Embodiment 0.35 0.68 0.65 0.03 Fourth Embodiment 0.19 0.34 0.64 0.06 Fifth Embodiment 0.10 0.68 0.85 0.01 Sixth Embodiment 0.06 0.21 0.66 0.08 Seventh Embodiment 0.22 0.80 0.66 0.02

[0179] As can be seen from Table 11, each embodiment satisfies the following conditional expressions: |SAG41| / |SAG42| < 20.0, 2.2 < (CT2 + CT3 + CT4) / (CT23 + CT34) ≤ 8.5, 0.35 < f / |f3| + f / |f4| < 0.8, |SAG61 / CT6| ≤ 1.8, 0.2 < ||R51| - |R52|| / ||R51| + |R52|| ≤ 0.8, f123 / |f56| ≤ 0.36, 0.60 < (CT1 + BF) / FNO ≤ 0.85, 6.1 < |f3| / n3 < 22.7, and ET34 / ImgH ≤ 0.12.

[0180] The technical features of the above embodiments can be combined arbitrarily. For the sake of brief description, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combinations of these technical features do not conflict, they should be considered as falling within the scope described in this specification.

[0181] The above embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the appended claims.

Claims

1. An optical system, characterized in that, There are a total of six lenses with refractive power, which successively include, from the object side to the image side along the optical axis direction: The first lens, having positive refractive power, and the object side surface of the first lens is convex; The second lens, having negative refractive power, and the image side surface of the second lens near the optical axis is concave; The third lens, having refractive power, and the object side surface of the third lens near the optical axis is convex; The fourth lens, having refractive power, and both the object side surface and the image side surface of the fourth lens are aspherical surfaces; The fifth lens, having positive refractive power, and the object side surface of the fifth lens near the circumference is concave, both the object side surface and the image side surface of the fifth lens are aspherical surfaces, and at least one of the object side surface and the image side surface of the fifth lens is provided with at least one inflection point; The sixth lens, having negative refractive power, and the object side surface of the sixth lens near the optical axis is convex, and the image side surface of the sixth lens near the optical axis is concave; both the object side surface and the image side surface of the sixth lens are aspherical surfaces, and at least one of the object side surface and the image side surface of the sixth lens is provided with at least one inflection point; The optical system satisfies the conditional formula: 2.2 < (CT2 + CT3 + CT4) / (CT23 + CT34) ≤ 8.5; 0.06 ≤ f123 / |f56| ≤ 0.36; 0.11 ≤ |SAG61 / CT6| ≤ 1.8; ET34 / ImgH ≤ 0.12; Wherein, 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, CT23 is the interval distance on the optical axis from the image side surface of the second lens to the object side surface of the third lens, CT34 is the interval distance on the optical axis from the image side surface of the third lens to the object side surface of the fourth lens; f123 is the total effective focal length of the first lens, the second lens and the third lens, f56 is the total effective focal length of the fifth lens and the sixth lens; SAG61 is the sagitta at the effective aperture of the object side surface of the sixth lens, CT6 is the thickness of the sixth lens on the optical axis; ET34 is the axial distance from the maximum effective aperture of the image side surface of the third lens to the maximum effective aperture of the object side surface of the fourth lens, ImgH is half of the diagonal length of the effective imaging area on the imaging surface of the optical system.

2. The optical system according to claim 1, characterized in that, The optical system satisfies the conditional formula: |SAG41| / |SAG42| < 20.0; Wherein, SAG41 is the sagitta at the maximum effective aperture of the object side surface of the fourth lens, SAG42 is the sagitta at the maximum effective aperture of the image side surface of the fourth lens.

3. The optical system according to claim 1, characterized in that, The optical system satisfies the conditional formula: 0.35 < f / |f3| + f / |f4| < 0.8; Wherein, f is the effective focal length of the optical system, f3 is the effective focal length of the third lens, f4 is the effective focal length of the fourth lens.

4. The optical system according to claim 1, characterized in that, The optical system satisfies the conditional formula: 0.2 < ||R51| - |R52|| / (|R51| + |R52|) ≤ 0.8; Wherein, R51 is the radius of curvature of the object side surface of the fifth lens at the optical axis, R52 is the radius of curvature of the image side surface of the fifth lens at the optical axis.

5. The optical system according to claim 1, wherein The optical system satisfies the conditional formula: 0.60mm < (CT1 + BF) / FNO ≤ 0.85mm; wherein, CT1 is the thickness of the first lens on the optical axis, BF is the axial distance from the farthest point on the image side of the sixth lens to the image plane, and FNO is the aperture number of the optical system.

6. The optical system according to claim 1, wherein The optical system satisfies the conditional formula: 6.1 < |f3| / n3 < 22.7; wherein, f3 is the effective focal length of the third lens, and n3 is the refractive index of the material of the third lens at a wavelength of 587.6nm.

7. A lens module, characterized in that, It includes a lens barrel, an electronic photosensitive element, and the optical system according to any one of claims 1 to 6. The first lens to the sixth lens of the optical system are installed in the lens barrel, and the electronic photosensitive element is arranged on the image side 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 sixth lens into an electrical signal of an image.

8. An electronic device, characterized in that, It includes a housing and the lens module according to claim 7. The lens module is arranged in the housing.

Images