Optical system, lens module and electronic device

Abstract

The application provides an optical system, a lens module and an electronic device. The optical system comprises a first lens to a seventh lens in sequence from an object side to an image side along an optical axis, wherein the fifth lens has a refractive power, the object side surface of the near-circumferential region of the fifth lens is a concave surface, the image side surface of the near-circumferential region of the fifth lens is a convex surface, the sixth lens has a refractive power, the object side surface of the near-circumferential region of the sixth lens is a concave surface, the image side surface of the near-circumferential region of the sixth lens is a convex surface, 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 seventh lens has a negative refractive power, the object side surface of the near-optical axis region of the seventh lens is a convex surface, the image side surface of the near-optical axis region of the seventh lens is a concave surface, and at least one of the object side surface and the image side surface of the seventh lens is provided with at least one inflection point. The above arrangement can eliminate aberration, shorten the total length of the optical system, be suitable for the design of large aperture and light and thin, and meet the high-pixel quality requirement.

Description

Technical Field

[0001] This invention belongs to the field of optical imaging technology, and particularly relates to an optical system, lens module and electronic device. Background Technology

[0002] With the development of science and technology, smartphones and smart electronic devices have become increasingly popular, and devices with diverse camera functions have gained widespread favor. At the same time, as consumer attitudes upgrade, higher demands are being placed on the slimness and lightness of mobile devices, the low-light shooting capabilities of camera equipment, and higher image quality. Existing lenses typically have apertures of f / 2.2 or higher, a thickness of less than 6mm, and a relatively small size, but their resolution is difficult to improve further. Due to the limitation of the f / 2.0 aperture, good shooting results are highly dependent on ambient light. Summary of the Invention

[0003] The purpose of this invention is to provide an optical system, lens module, and electronic device, which has the effects of large aperture and thinness.

[0004] To achieve the objectives of this invention, the following technical solution is provided:

[0005] In a first aspect, the present invention provides an optical system comprising, from the object side to the image side along the optical axis: a first lens having positive refractive power, wherein the object side of the first lens is convex and the image side of the first lens in the near-optical axis region is concave; a second lens having negative refractive power, wherein the object side of the second lens in the near-optical axis region is convex and the image side of the second lens is concave; a third lens having positive refractive power, wherein the object side of the third lens is convex; a fourth lens having refractive power, wherein the object side of the fourth lens in the near-optical axis region is convex and the image side of the fourth lens in the near-optical axis region is convex; and a fifth lens having refractive power, wherein the object side of the fifth lens in the near-circumferential region is concave. The fifth lens has a convex image-side surface in the near-circumferential region, and both its object-side and image-side surfaces are aspherical. The sixth lens has refractive power; its object-side surface in the near-circumferential region is concave, and its image-side surface in the near-circumferential region is convex. Both its object-side and image-side surfaces are aspherical, and at least one of its object-side and image-side surfaces has at least one inflection point. The seventh lens has negative refractive power; its object-side surface in the near-optical axis region is convex, and its image-side surface in the near-optical axis region is concave. Both its object-side and image-side surfaces are aspherical, and at least one of its object-side and image-side surfaces has at least one inflection point.

[0006] By employing a seven-element lens structure, using aspherical surfaces, and adding a refractive point, aberrations can be eliminated, the overall length of the optical system reduced, and the refractive power configured rationally. This makes the optical system more flexible, suitable for designs with large apertures and slim profiles, while simultaneously achieving high-resolution image quality. The large-aperture stop design allows the optical system to have a minimum aperture number (FNO) of 1.4, which is smaller than the FNO of existing lens groups (FNO 2.0 and above), resulting in greater light intake and better image quality.

[0007] In one embodiment, the optical system satisfies the condition: 1.4 ≤ f / EPD ≤ 2.0; where f is the effective focal length of the optical system, and EPD is the entrance pupil diameter of the optical system. Satisfying this relationship ensures sufficient light intake for the optical system, preventing vignetting around the edges of the image plane. Furthermore, when f / EPD ≤ 1.7, sufficient incident light improves shooting performance in low-light environments. On the other hand, reducing the aperture number reduces the size of the Airy disk, resulting in a higher resolution limit. Combined with a properly configured lens refractive power, the demand for high-resolution image quality can be met.

[0008] In one embodiment, the optical system satisfies the condition: 1.3 < TTL / ImgH < 1.7; where TTL is the distance from the object side of the first lens to the imaging plane on the optical axis, and ImgH is half the diagonal length of the effective pixel area on the imaging plane. Satisfying the above formula allows the lens to support high-pixel electronic image sensors; reducing TTL allows for compression of the entire imaging lens group's length, making it easier to achieve ultra-thinness and miniaturization. Combined with a rationally configured lens shape and refractive power, the system maintains both structural compactness and good imaging quality.

[0009] In one embodiment, the optical system satisfies the condition: 0.9 < SD11 / SD31 < 1.3; where SD11 is the effective half-aperture of the object-side surface of the first lens, and SD31 is the effective half-aperture of the object-side surface of the third lens. Satisfying the above formula compresses the size of the first, second, and third lenses at the head of the optical system, facilitating a small-head design for the optical system, while simultaneously improving image plane illumination, ensuring a suitable light deflection angle, and reducing the sensitivity of the optical system.

[0010] In one embodiment, the optical system satisfies the condition: |f / f4|≤0.30; where f is the effective focal length of the optical system and f4 is the effective focal length of the fourth lens. The fourth lens provides a portion of the positive or negative refractive power, adjusting the overall refractive power of the optical system. It forms a near-symmetrical structure with the first, second, and third lenses at the head of the optical system, balancing the distortion generated at the head of the optical system and avoiding higher-order aberrations caused by excessive refractive index.

[0011] In one embodiment, the optical system satisfies the condition: |f6 / R61| < 10.0; where f6 is the effective focal length of the sixth lens, and R61 is the radius of curvature of the near-optical axis region on the object side of the sixth lens. The sixth lens includes at least one inflection point, which can effectively improve the aberrations generated by the first to fifth lenses and enhance resolution.

[0012] In one embodiment, the optical system satisfies the condition: 0.50 ≤ (CT4 + T45) / (CT5 + CT6) ≤ 0.81; where CT4 is the thickness of the fourth lens on the optical axis, T45 is the distance between the fourth and fifth lenses on the optical axis, CT5 is the thickness of the fifth lens on the optical axis, and CT6 is the thickness of the sixth lens on the optical axis. Satisfying this condition maintains appropriate thicknesses of the fourth, fifth, and sixth lenses on the optical axis and a reasonable lens spacing, effectively improving the compactness of the lens structure and facilitating lens molding and assembly.

[0013] In one embodiment, the optical system satisfies the condition: 0.22 ≤ |R71-R72| / |R71+R72| < 0.8; where R71 is the radius of curvature of the near-optical axis region on the object side of the seventh lens, and R72 is the radius of curvature of the near-optical axis region on the image side of the seventh lens. Satisfying the above formula helps to correct aberrations generated by the optical system at large apertures, resulting in a uniform distribution of refractive forces perpendicular to the optical axis, significantly correcting distortions and aberrations generated by the first to sixth lenses, while avoiding excessive bending of the seventh lens and facilitating its molding and manufacturing.

[0014] In one embodiment, the optical system satisfies the condition: R22 / R31 < 1.3; where R22 is the radius of curvature of the near-optical axis region on the image side of the second lens, and R31 is the radius of curvature of the near-optical axis region on the object side of the third lens. Satisfying this condition, R22 and R31 form a "matching" relationship, reducing light reflection on the lens surface, improving illumination and image quality, and avoiding stray light interference.

[0015] Secondly, the present invention also provides a lens module including the optical system described in any embodiment of the first aspect. By incorporating the optical system provided by the present invention into the lens module, the lens module achieves the effects of a large aperture, high image quality, and a thinner profile.

[0016] Thirdly, the present invention also provides an electronic device comprising a housing and the lens module described in the second aspect, wherein the lens module is disposed within the housing. By incorporating the lens module provided by the present invention into the electronic device, the lens module achieves the effects of a large aperture, high image quality, and thinness, enabling the capture of images with good image quality in low-light environments. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1a This is a schematic diagram of the optical system of the first embodiment;

[0019] Figure 1b These are the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the first embodiment;

[0020] Figure 2a This is a schematic diagram of the optical system of the second embodiment;

[0021] Figure 2b The longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the second embodiment;

[0022] Figure 3a This is a schematic diagram of the optical system of the third embodiment;

[0023] Figure 3b The longitudinal spherical aberration curve, astigmatism curve, and distortion curve are from the third embodiment;

[0024] Figure 4a This is a schematic diagram of the optical system of the fourth embodiment;

[0025] Figure 4b These are the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the fourth embodiment;

[0026] Figure 5a This is a schematic diagram of the optical system of the fifth embodiment;

[0027] Figure 5b These are the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the fifth embodiment;

[0028] Figure 6a This is a schematic diagram of the optical system in the sixth embodiment;

[0029] Figure 6b The sixth embodiment includes the longitudinal spherical aberration curve, astigmatism curve, and distortion curve;

[0030] Figure 7a This is a schematic diagram of the optical system in the sixth embodiment;

[0031] Figure 7b The sixth embodiment includes the longitudinal spherical aberration curve, astigmatism curve, and distortion curve. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] This invention provides a lens module comprising a lens barrel and an optical system provided in this invention. The first to seventh lenses of the optical system are mounted within the lens barrel. This lens module can be a standalone lens for a digital camera or an imaging module integrated into an electronic device such as a smartphone. By incorporating the optical system provided in this invention into the lens module, the lens module achieves the effects of a large aperture, high image quality, and a slim design.

[0034] This invention provides an electronic device comprising a housing and a lens module provided in this invention, the lens module being disposed within the housing. Further, the electronic device may also include an electronic photosensitive element, the photosensitive surface of which serves as the imaging surface of the optical system. Light rays from an object passing through the first to seventh lenses and incident on the photosensitive surface of the electronic photosensitive element can be converted into electrical signals for an image. The electronic photosensitive element can be a complementary metal-oxide-semiconductor (CMOS) or a charge-coupled device (CCD). This electronic device can be a smartphone, personal digital assistant (PDA), tablet computer, smartwatch, drone, e-book reader, dashcam, wearable device, etc. By incorporating the lens module provided in this invention into the electronic device, the lens module achieves a large aperture, high image quality, and a slim profile, enabling the capture of high-quality images in low-light conditions.

[0035] The optical system provided in this embodiment of the invention comprises, from the object side to the image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens in sequence along the optical axis. Air gaps may exist between any two adjacent lenses in the first to seventh lenses.

[0036] Specifically, the shape and structure of the seven lenses are as follows:

[0037] A first lens has positive refractive power, its object-side surface is convex, and its image-side surface near the optical axis is concave. A second lens has negative refractive power, its object-side surface near the optical axis is convex, and its image-side surface is concave. A third lens has positive refractive power, and its object-side surface is convex. A fourth lens has refractive power, its object-side surface near the optical axis is convex, and its image-side surface near the optical axis is convex. A fifth lens has refractive power, its object-side surface near the circumference is concave, and its image-side surface near the circumference is convex; both its object-side and image-side surfaces are aspherical. A sixth lens has refractive power, its object-side surface near the circumference is concave, and its image-side surface near the circumference is convex; both its object-side and image-side surfaces are aspherical, and at least one of its object-side and image-side surfaces has at least one inflection point. The seventh lens has negative refractive power. The object-side surface of the seventh lens near the optical axis is convex, and the image-side surface of the seventh lens near the optical axis is concave. Both the object-side surface and the image-side surface of the seventh lens are aspherical. At least one of the object-side surface and the image-side surface of the seventh lens has at least one inversion point.

[0038] The optical system also includes an aperture stop, which can be located at any position between the first lens and the seventh lens, such as on the object side of the first lens.

[0039] By employing a seven-element lens structure, using aspherical surfaces, and adding a refractive point, aberrations can be eliminated, the overall length of the optical system reduced, and the refractive power configured rationally. This makes the optical system more flexible, suitable for designs with large apertures and slim profiles, while simultaneously achieving high-resolution image quality. The large-aperture stop design allows the optical system to have a minimum aperture number (FNO) of 1.4, which is smaller than the FNO of existing lens groups (FNO 2.0 and above), resulting in greater light intake and better image quality.

[0040] In one embodiment, the optical system satisfies the condition: 1.4 ≤ f / EPD ≤ 2.0; where f is the effective focal length of the optical system and EPD is the entrance pupil diameter of the optical system.

[0041] In this embodiment, the aperture stop is a front aperture stop, meaning it is located on the object-side side of the first lens. The entrance pupil diameter is the light entry point of the optical system and is approximately the same as the diameter of the aperture stop. Satisfying the above relationship ensures sufficient light intake for the optical system, preventing vignetting around the edges of the image plane. Furthermore, when f / EPD ≤ 1.7, sufficient incident light improves shooting performance in low-light conditions. On the other hand, reducing the aperture number reduces the size of the Airy disk, resulting in a higher resolution limit. Combined with a properly configured lens refractive power, the requirements for high-resolution image quality can be met.

[0042] In one embodiment, the optical system satisfies the condition: 1.3 < TTL / ImgH < 1.7; where TTL is the distance from the object side of the first lens to the imaging plane on the optical axis, and ImgH is half the diagonal length of the effective pixel area on the imaging plane.

[0043] In this embodiment, ImgH is the half-image height, which determines the size of the electronic image sensor. The larger ImgH is, the larger the maximum size of the electronic image sensor that can be supported. Satisfying the above formula allows the lens to support high-pixel electronic image sensors; the reduction of TTL allows for the compression of the entire imaging lens group length, making it easier to achieve ultra-thinness and miniaturization. By combining the surface shape and refractive power of each lens with a reasonable configuration, the compactness of the structure and good image quality can be maintained.

[0044] In one embodiment, the optical system satisfies the condition: 0.9 < SD11 / SD31 < 1.3; where SD11 is the effective half-aperture of the object side of the first lens, and SD31 is the effective half-aperture of the object side of the third lens.

[0045] In this embodiment, if SD11 / SD31≤0.9, SD31 is significantly larger than SD11, making it difficult to control aberrations and image plane illumination for edge rays; if SD11 / SD31≥1.3, the deflection angle of edge rays is prone to be too large, increasing the sensitivity of the optical system. Satisfying the above formula compresses the size of the first, second, and third lenses in the optical system head, making it easier to achieve a small head design for the optical system, while improving image plane illumination, resulting in a suitable light deflection angle and reducing the sensitivity of the optical system.

[0046] In one embodiment, the optical system satisfies the condition: |f / f4|≤0.30; where f is the effective focal length of the optical system and f4 is the effective focal length of the fourth lens.

[0047] In this embodiment, the fourth lens provides a portion of the positive or negative refractive power to adjust the overall refractive power of the optical system. It forms a near-symmetrical structure with the first, second, and third lenses at the head of the optical system, balancing the distortion generated at the head of the optical system and avoiding higher-order aberrations caused by excessive refractive index.

[0048] In one embodiment, the optical system satisfies the condition: |f6 / R61|<10.0; where f6 is the effective focal length of the sixth lens, and R61 is the radius of curvature of the near-optical axis region on the object side of the sixth lens.

[0049] In this embodiment, the sixth lens includes at least one inversion point, which can effectively improve the aberrations generated by the first to fifth lenses and enhance the resolution.

[0050] In one embodiment, the optical system satisfies the condition: 0.50≤(CT4+T45) / (CT5+CT6)≤0.81; where CT4 is the thickness of the fourth lens on the optical axis, T45 is the distance between the fourth lens and the fifth lens on the optical axis, CT5 is the thickness of the fifth lens on the optical axis, and CT6 is the thickness of the sixth lens on the optical axis.

[0051] In this embodiment, the rationality of thickness and gap is directly related to the difficulty of lens forming and manufacturing. Satisfying the above formula can keep the thickness of the fourth lens, fifth lens and sixth lens on the optical axis appropriate, and the lens spacing reasonable, which can effectively improve the compactness of the lens structure and facilitate lens forming and assembly.

[0052] In one embodiment, the optical system satisfies the condition: 0.22≤|R71-R72| / |R71+R72|<0.8; where R71 is the radius of curvature of the near-optical axis region on the object side of the seventh lens, and R72 is the radius of curvature of the near-optical axis region on the image side of the seventh lens.

[0053] In this embodiment, satisfying the above formula is beneficial for correcting aberrations generated by the optical system at large apertures, making the refractive force distribution uniform in the direction perpendicular to the optical axis, significantly correcting the distortion and aberrations generated by the first to sixth lenses, while avoiding excessive bending of the seventh lens, and making it easy to form and manufacture.

[0054] In one embodiment, the optical system satisfies the condition: R22 / R31 < 1.3; where R22 is the radius of curvature of the near-optical axis region on the image side of the second lens, and R31 is the radius of curvature of the near-optical axis region on the object side of the third lens.

[0055] In this embodiment, the above formula is satisfied, and R22 and R31 form a "cooperation" shape, which reduces the reflection of light on the lens surface, improves illuminance and image quality, and avoids the influence of stray light.

[0056] First Embodiment

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

[0058] The first lens L1 has positive refractive power. The object-side surface S1 of the near-optical axis region and the near-circumferential region of the first lens L1 is convex, and the image-side surface S2 of the near-optical axis region of the first lens L1 is concave and the image-side surface S2 of the near-circumferential region is convex.

[0059] The second lens L2 has negative refractive power. The object-side surface S3 of the near-optical axis region and the near-circular region of the second lens L2 are both convex surfaces, and the image-side surface S4 of the near-optical axis region and the near-circular region of the second lens L2 are both concave surfaces.

[0060] The third lens L3 has positive refractive power. The object-side surface S5 of the near-optical axis region and the near-circumferential region of the third lens L3 are both convex surfaces. The image-side surface S6 of the near-optical axis region of the third lens L3 is concave, and the image-side surface S6 of the near-circumferential region is convex.

[0061] The fourth lens L4 has positive refractive power. The object-side surface S7 of the near-optical axis region and the near-circumferential region of the fourth lens L4 are both concave, and the image-side surface S8 of the near-optical axis region and the near-circumferential region of the fourth lens L4 are both convex.

[0062] The fifth lens L5 has negative refractive power. The object-side surface S9 of the fifth lens L5 near the optical axis is convex, and the object-side surface S9 near the circumference is concave. The image-side surface S10 of the fifth lens L5 near the optical axis is concave, and the image-side surface S10 near the circumference is convex.

[0063] The sixth lens L6 has negative refractive power. The object-side surface S11 of the sixth lens L6 near the optical axis is convex, and the object-side surface S11 near the circumference is concave. The image-side surface S12 of the sixth lens L6 near the optical axis is concave, and the image-side surface S12 near the circumference is convex.

[0064] The seventh lens L7 has negative refractive power. The object-side surface S13 of the seventh lens L7 near the optical axis is convex, and the object-side surface S13 near the circumference is concave. The image-side surface S14 of the seventh lens L7 near the optical axis is concave, and the image-side surface S14 near the circumference is convex.

[0065] The first lens L1 to the seventh lens L7 mentioned above are all made of plastic.

[0066] In addition, the optical system also includes an aperture stop STO, an infrared cut-off filter L8, and an imaging surface S17. The aperture stop STO is located on the object-side side of the first lens L1, i.e., the side of the first lens L1 furthest from the second lens L2, and is used to control the amount of light entering the lens. In other embodiments, the aperture stop STO can also be located between two adjacent lenses, or on other lenses. The infrared cut-off filter L8 is located on the image-side side of the seventh lens L7, and includes an object-side side S15 and an image-side side S16. The infrared cut-off filter L8 filters out infrared light, ensuring that the light entering the imaging surface S17 is visible light with a wavelength of 380nm-780nm. The infrared cut-off filter L8 is made of glass and can be coated. The imaging surface S17 is the effective pixel area of ​​the electronic photosensitive element.

[0067] Table 1a shows the characteristics of the optical system of this embodiment, where the data were obtained using light with a wavelength of 546 nm, and the units for Y radius, thickness and focal length are millimeters (mm).

[0068] Table 1a

[0069]

[0070]

[0071] Where f 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 on the optical axis from the object side of the first lens L1 to the imaging surface S17 of the optical system.

[0072] In this embodiment, the object-side surface and image-side surface of any one of the lenses from the first lens L1 to the seventh lens L7 are aspherical. The surface shape x of each aspherical lens can be defined using, but is not limited to, the following aspherical formula:

[0073]

[0074] Where x is the distance vector from the vertex of the aspherical surface at a height of h along the optical axis; 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 i-th order correction coefficient of the aspherical surface. Table 1b gives the higher-order coefficients A4, A6, A8, A10, A12, A14, A15, A17 and A18 that can be used for each aspherical mirror S1-S14 in the first embodiment.

[0075] Table 1b

[0076]

[0077]

[0078] 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 represents the deviation of the focal point of light rays of different wavelengths after passing through the lenses of the optical system; the astigmatism curve represents the meridional and sagittal image plane curvature; and the distortion curve represents the distortion magnitude corresponding to different field of view angles. According to... Figure 1b It can be seen that the optical system given in the first embodiment can achieve good imaging quality.

[0079] Second Embodiment

[0080] Please refer to Figure 2a and Figure 2b The optical system of this embodiment includes, from the object side to the image side along the optical axis:

[0081] The first lens L1 has positive refractive power. The object-side surface S1 of the near-optical axis region and the near-circumferential region of the first lens L1 is convex, and the image-side surface S2 of the near-optical axis region of the first lens L1 is concave and the image-side surface S2 of the near-circumferential region is convex.

[0082] The second lens L2 has positive refractive power. The object-side surface S3 of the near-optical axis region and the near-circumferential region of the second lens L2 are both convex surfaces, and the image-side surface S4 of the near-optical axis region and the near-circumferential region of the second lens L2 are both concave surfaces.

[0083] The third lens L3 has positive refractive power. The object-side surface S5 of the near-optical axis region and the near-circumferential region of the third lens L3 are both convex surfaces. The image-side surface S6 of the near-optical axis region of the third lens L3 is concave, and the image-side surface S6 of the near-circumferential region is convex.

[0084] The fourth lens L4 has negative refractive power. The object-side surface S7 of the near-optical axis region and the near-circular region of the fourth lens L4 is concave, and the image-side surface S8 of the near-optical axis region of the fourth lens L4 is convex and the image-side surface S8 of the near-circular region is concave.

[0085] The fifth lens L5 has positive refractive power. The object-side surface S9 of the fifth lens L5 near the optical axis is convex, and the object-side surface S9 near the circumference is concave. The image-side surface S10 of the fifth lens L5 near the optical axis is concave, and the image-side surface S10 near the circumference is convex.

[0086] The sixth lens L6 has negative refractive power. The object-side surface S11 of the near-optical axis region and the near-circumferential region of the sixth lens L6 are both concave, and the image-side surface S12 of the near-optical axis region and the near-circumferential region of the sixth lens L6 are both convex.

[0087] The seventh lens L7 has negative refractive power. The object-side surface S13 of the seventh lens L7 near the optical axis is convex, and the object-side surface S13 near the circumference is concave. The image-side surface S14 of the seventh lens L7 near the optical axis is concave, and the image-side surface S14 near the circumference is convex.

[0088] The other structures of the second embodiment are the same as those of the first embodiment, and can be referred to accordingly.

[0089] Table 2a shows the characteristics of the optical system of this embodiment, where the data were obtained using light with a wavelength of 546 nm, and the units for Y radius, thickness and focal length are millimeters (mm).

[0090] Table 2a

[0091]

[0092]

[0093] The meanings of the parameters in Table 2a are the same as those in the first embodiment.

[0094] Table 2b gives the higher-order coefficients that can be used for each aspherical mirror in the second embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0095] Table 2b

[0096]

[0097] 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 represents the deviation of the focal point of light rays of different wavelengths after passing through the lenses of the optical system; the astigmatism curve represents the meridional and sagittal image plane curvature; and the distortion curve represents the distortion magnitude corresponding to different field of view angles. According to... Figure 2b It can be seen that the optical system given in the second embodiment can achieve good imaging quality.

[0098] Third Embodiment

[0099] Please refer to Figure 3a and Figure 3b The optical system of this embodiment includes, from the object side to the image side along the optical axis:

[0100] The first lens L1 has positive refractive power. The object-side surface S1 of the near-optical axis region and the near-circumferential region of the first lens L1 is convex, and the image-side surface S2 of the near-optical axis region of the first lens L1 is concave and the image-side surface S2 of the near-circumferential region is convex.

[0101] The second lens L2 has negative refractive power. The object-side surface S3 of the near-optical axis region and the near-circular region of the second lens L2 are both convex surfaces, and the image-side surface S4 of the near-optical axis region and the near-circular region of the second lens L2 are both concave surfaces.

[0102] The third lens L3 has positive refractive power. The object-side surface S5 of the third lens L3 near the optical axis is convex, and the object-side surface S5 near the circumference is concave. The image-side surface S6 of the third lens L3 near the optical axis is concave, and the image-side surface S6 near the circumference is convex.

[0103] The fourth lens L4 has positive refractive power. The object-side surface S7 of the near-optical axis region and the near-circumferential region of the fourth lens L4 are both concave, and the image-side surface S8 of the near-optical axis region and the near-circumferential region of the fourth lens L4 are both convex.

[0104] The fifth lens L5 has negative refractive power. The object-side surface S9 of the fifth lens L5 near the optical axis is convex, and the object-side surface S9 near the circumference is concave. The image-side surface S10 of the fifth lens L5 near the optical axis is concave, and the image-side surface S10 near the circumference is convex.

[0105] The sixth lens L6 has negative refractive power. The object-side surface S11 of the sixth lens L6 near the optical axis is convex, and the object-side surface S11 near the circumference is concave. The image-side surface S12 of the sixth lens L6 near the optical axis is concave, and the image-side surface S12 near the circumference is convex.

[0106] The seventh lens L7 has negative refractive power. The object-side surface S13 of the seventh lens L7 near the optical axis is convex, and the object-side surface S13 near the circumference is concave. The image-side surface S14 of the seventh lens L7 near the optical axis is concave, and the image-side surface S14 near the circumference is convex.

[0107] The other structures of the third embodiment are the same as those of the first embodiment, and can be referred to accordingly.

[0108] Table 3a shows the characteristics of the optical system of this embodiment, where the data were obtained using light with a wavelength of 546 nm, and the units for Y radius, thickness and focal length are millimeters (mm).

[0109] Table 3a

[0110]

[0111]

[0112] The meanings of the parameters in Table 3a are the same as those in the first embodiment.

[0113] Table 3b gives the higher-order coefficients that can be used for each aspherical mirror in the third embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0114] Table 3b

[0115]

[0116] 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 represents the deviation of the focal point of light rays of different wavelengths after passing through the lenses of the optical system; the astigmatism curve represents the meridional and sagittal image plane curvature; and the distortion curve represents the distortion magnitude corresponding to different field of view angles. According to... Figure 3b It can be seen that the optical system given in the third embodiment can achieve good imaging quality.

[0117] Fourth embodiment

[0118] Please refer to Figure 4a and Figure 4b The optical system of this embodiment includes, from the object side to the image side along the optical axis:

[0119] The first lens L1 has positive refractive power. The object-side surface S1 of the near-optical axis region and the near-circumferential region of the first lens L1 is convex, and the image-side surface S2 of the near-optical axis region of the first lens L1 is concave and the image-side surface S2 of the near-circumferential region is convex.

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

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

[0122] The fourth lens L4 has positive refractive power. The object-side surface S7 of the near-optical axis region and the near-circumferential region of the fourth lens L4 are both concave, and the image-side surface S8 of the near-optical axis region and the near-circumferential region of the fourth lens L4 are both convex.

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

[0124] The sixth lens L6 has positive refractive power. The object-side surface S11 of the sixth lens L6 near the optical axis is convex, and the object-side surface S11 near the circumference is concave. The image-side surface S12 of the sixth lens L6 near the optical axis is concave, and the image-side surface S12 near the circumference is convex.

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

[0126] The other structures of the fourth embodiment are the same as those of the first embodiment, and can be referred to accordingly.

[0127] Table 4a shows the characteristics of the optical system of this embodiment, where the data were obtained using light with a wavelength of 546 nm, and the units for Y radius, thickness and focal length are millimeters (mm).

[0128] Table 4a

[0129]

[0130] The meanings of the parameters in Table 4a are the same as those in the first embodiment.

[0131] Table 4b gives the higher-order coefficients that can be used for each aspherical mirror in the fourth embodiment, wherein each aspherical surface shape can be defined by the formula given in the fourth embodiment.

[0132] Table 4b

[0133]

[0134]

[0135] 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 represents the deviation of the focal point of light rays of different wavelengths after passing through the lenses of the optical system; the astigmatism curve represents the meridional and sagittal image plane curvature; and the distortion curve represents the distortion magnitude corresponding to different field of view angles. According to... Figure 4b It can be seen that the optical system given in the fourth embodiment can achieve good imaging quality.

[0136] Fifth Embodiment

[0137] Please refer to Figure 5a and Figure 5b The optical system of this embodiment includes, from the object side to the image side along the optical axis:

[0138] The first lens L1 has positive refractive power. The object-side surface S1 of the near-optical axis region and the near-circumferential region of the first lens L1 is convex, and the image-side surface S2 of the near-optical axis region of the first lens L1 is concave and the image-side surface S2 of the near-circumferential region is convex.

[0139] The second lens L2 has negative refractive power. The object-side surface S3 of the near-optical axis region and the near-circular region of the second lens L2 are both convex surfaces, and the image-side surface S4 of the near-optical axis region and the near-circular region of the second lens L2 are both concave surfaces.

[0140] The third lens L3 has positive refractive power. The object-side surface S5 of the near-optical axis region and the near-circumferential region of the third lens L3 are both convex surfaces. The image-side surface S6 of the near-optical axis region of the third lens L3 is concave, and the image-side surface S6 of the near-circumferential region is convex.

[0141] The fourth lens L4 has positive refractive power. The object-side surface S7 of the near-optical axis region and the near-circumferential region of the fourth lens L4 are both concave, and the image-side surface S8 of the near-optical axis region and the near-circumferential region of the fourth lens L4 are both convex.

[0142] The fifth lens L5 has negative refractive power. The object-side surface S9 of the near-optical axis region and the near-circular region of the fifth lens L5 are both concave; the image-side surface S10 of the near-optical axis region and the near-circular region of the fifth lens L5 are both convex.

[0143] The sixth lens L6 has positive refractive power. The object-side surface S11 of the sixth lens L6 near the optical axis is convex, and the object-side surface S11 near the circumference is concave. The image-side surface S12 of the sixth lens L6 near the optical axis is concave, and the image-side surface S12 near the circumference is convex.

[0144] The seventh lens L7 has negative refractive power. The object-side surface S13 of the near-optical axis region and the near-circumferential region of the seventh lens L7 are both convex. The image-side surface S14 of the near-optical axis region of the seventh lens L7 is concave, and the image-side surface S14 of the near-circumferential region is convex.

[0145] The other structures of the fifth embodiment are the same as those of the first embodiment, and can be referred to accordingly.

[0146] Table 5a shows the characteristics of the optical system of this embodiment, where the data were obtained using light with a wavelength of 546 nm, and the units for Y radius, thickness and focal length are millimeters (mm).

[0147] Table 5a

[0148]

[0149] The meanings of the parameters in Table 5a are the same as those in the first embodiment.

[0150] Table 5b gives the higher-order coefficients that can be used for each aspherical mirror in the fifth embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0151] Table 5b

[0152]

[0153]

[0154] 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 represents the deviation of the focal point of light rays of different wavelengths after passing through the lenses of the optical system; the astigmatism curve represents the meridional and sagittal image plane curvature; and the distortion curve represents the distortion magnitude corresponding to different field of view angles. According to... Figure 5b It can be seen that the optical system given in the fifth embodiment can achieve good imaging quality.

[0155] Sixth Embodiment

[0156] Please refer to Figure 6a and Figure 6b The optical system of this embodiment includes, from the object side to the image side along the optical axis:

[0157] The first lens L1 has positive refractive power. The object-side surface S1 of the near-optical axis region and the near-circumferential region of the first lens L1 is convex, and the image-side surface S2 of the near-optical axis region of the first lens L1 is concave and the image-side surface S2 of the near-circumferential region is convex.

[0158] The second lens L2 has negative refractive power. The object-side surface S3 of the near-optical axis region and the near-circular region of the second lens L2 are both convex surfaces, and the image-side surface S4 of the near-optical axis region and the near-circular region of the second lens L2 are both concave surfaces.

[0159] The third lens L3 has positive refractive power. The object-side surface S5 of the near-optical axis region and the near-circumferential region of the third lens L3 are both convex surfaces. The image-side surface S6 of the near-optical axis region of the third lens L3 is concave, and the image-side surface S6 of the near-circumferential region is convex.

[0160] The fourth lens L4 has positive refractive power. The object-side surface S7 of the near-optical axis region and the near-circumferential region of the fourth lens L4 are both concave, and the image-side surface S8 of the near-optical axis region and the near-circumferential region of the fourth lens L4 are both convex.

[0161] The fifth lens L5 has negative refractive power. The object-side surface S9 of the fifth lens L5 near the optical axis is convex, and the object-side surface S9 near the circumference is concave. The image-side surface S10 of the fifth lens L5 near the optical axis is concave, and the image-side surface S10 near the circumference is convex.

[0162] The sixth lens L6 has positive refractive power. The object-side surface S11 of the sixth lens L6 near the optical axis is convex, and the object-side surface S11 near the circumference is concave. The image-side surface S12 of the sixth lens L6 near the optical axis and near the circumference are both convex.

[0163] The seventh lens L7 has negative refractive power. The object-side surface S13 of the near-optical axis region and the near-circumferential region of the seventh lens L7 are both convex. The image-side surface S14 of the near-optical axis region of the seventh lens L7 is concave, and the image-side surface S14 of the near-circumferential region is convex.

[0164] The other structures of the sixth embodiment are the same as those of the first embodiment, and can be referred to accordingly.

[0165] Table 6a shows the characteristics of the optical system of this embodiment, where the data were obtained using light with a wavelength of 546 nm, and the units for Y radius, thickness and focal length are millimeters (mm).

[0166] Table 6a

[0167]

[0168]

[0169] The meanings of the parameters in Table 6a are the same as those in the first embodiment.

[0170] Table 6b gives the higher-order coefficients that can be used for each aspherical mirror in the sixth embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0171] Table 6b

[0172]

[0173] 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 represents the deviation of the focal point of light rays of different wavelengths after passing through the lenses of the optical system; the astigmatism curve represents the meridional and sagittal image plane curvature; and the distortion curve represents the distortion magnitude corresponding to different field of view angles. According to... Figure 6b It can be seen that the optical system given in the sixth embodiment can achieve good imaging quality.

[0174] Seventh Embodiment

[0175] Please refer to Figure 7a and Figure 7b The optical system of this embodiment includes, from the object side to the image side along the optical axis:

[0176] The first lens L1 has positive refractive power. The object-side surface S1 of the near-optical axis region and the near-circumferential region of the first lens L1 is convex, and the image-side surface S2 of the near-optical axis region of the first lens L1 is concave and the image-side surface S2 of the near-circumferential region is convex.

[0177] The second lens L2 has negative refractive power. The object-side surface S3 of the near-optical axis region and the near-circular region of the second lens L2 are both convex surfaces, and the image-side surface S4 of the near-optical axis region and the near-circular region of the second lens L2 are both concave surfaces.

[0178] The third lens L3 has positive refractive power. The object-side surface S5 of the near-optical axis region and the near-circumferential region of the third lens L3 are both convex surfaces. The image-side surface S6 of the near-optical axis region of the third lens L3 is concave, and the image-side surface S6 of the near-circumferential region is convex.

[0179] The fourth lens L4 has positive refractive power. The object-side surface S7 of the near-optical axis region and the near-circumferential region of the fourth lens L4 are both concave, and the image-side surface S8 of the near-optical axis region and the near-circumferential region of the fourth lens L4 are both convex.

[0180] The fifth lens L5 has positive refractive power. The object-side surface S9 of the fifth lens L5 near the optical axis is convex, and the object-side surface S9 near the circumference is concave. The image-side surface S10 of the fifth lens L5 near the optical axis is concave, and the image-side surface S10 near the circumference is convex.

[0181] The sixth lens L6 has positive refractive power. The object-side surface S11 of the sixth lens L6 near the optical axis is convex, and the object-side surface S11 near the circumference is concave. The image-side surface S12 of the sixth lens L6 near the optical axis is concave, and the image-side surface S12 near the circumference is convex.

[0182] The seventh lens L7 has negative refractive power. The object-side surface S13 of the seventh lens L7 near the optical axis is convex, and the object-side surface S13 near the circumference is concave. The image-side surface S14 of the seventh lens L7 near the optical axis is concave, and the image-side surface S14 near the circumference is convex.

[0183] The other structures of the seventh embodiment are the same as those of the first embodiment, and can be referred to accordingly.

[0184] Table 7a shows the characteristics of the optical system of this embodiment, where the data were obtained using light with a wavelength of 546 nm, and the units for Y radius, thickness and focal length are millimeters (mm).

[0185] Table 7a

[0186]

[0187]

[0188] Among them, the meanings of the parameters in Table 7a are the same as those of the parameters in the first embodiment.

[0189] Table 7b gives the high-order term coefficients of the aspherical mirrors that can be used in the seventh embodiment. Among them, each aspherical surface type can be defined by the formula given in the first embodiment.

[0190] Table 7b

[0191]

[0192] Figure 7b shows the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the seventh 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 curvature of the meridional image plane and the sagittal image plane; the distortion curve represents the distortion magnitude values corresponding to different field angles. According to Figure 7b it can be seen that the optical system given in the seventh embodiment can achieve good imaging quality.

[0193] Table 8 shows the values of GTL7 / ITL7, CDL1 / Imgh, Fno / TTL, <TTL / DL, TTL / Imgh, TTL / f, f1 / f, (R1+R2) / f1, R5 / R6, f3 / f, (R9+R10) / (R9-R10) and FBL / TTL in the optical systems of the first embodiment to the sixth embodiment.

[0194] Table 8

[0195]

[0196] It can be seen from Table 8 that the optical systems of the first embodiment to the seventh embodiment all satisfy the following conditional expressions: 1.4≤f / EPD≤2.0, 1.3<TTL / ImgH<1.7, 0.9<SD11 / SD31<1.3, |f / f4|≤0.30, |f6 / R61|<10.0, 0.50≤(CT4+T45) / (CT5+CT6)≤0.81, 0.22≤|R71-R72| / |R(71+R72|<0.8, R22 / R31<1.3. Among them, the image side near the optical axis region of the sixth lens in the first embodiment is a plane, and the radius of curvature is infinite. 1.00E+17 is obtained by calculating the direct reading value of the design software, and its meaning is infinite.

[0197] The above-disclosed is only a preferred embodiment of the present invention. Of course, the scope of rights of the present invention cannot be limited by this. Those of ordinary skill in the art can understand the whole or part of the processes of implementing the above embodiments, and the equivalent changes made according to the claims of the present invention still fall within the scope covered by the invention.

Claims

1. An optical system characterized by comprising: There are seven lenses with refractive power, which are sequentially arranged from the object side to the image side along the optical axis direction, and include: a first lens with positive refractive power, the object side surface of the first lens is convex, and the image side surface of the near optical axis region of the first lens is concave; a second lens with negative refractive power, the object side surface of the near optical axis region of the second lens is convex, and the image side surface of the second lens is concave; a third lens with positive refractive power, the object side surface of the third lens is convex, and both the object side surface and the image side surface of the third lens are aspherical surfaces; a fourth lens with refractive power, the object side surface of the near optical axis region of the fourth lens is convex, and the image side surface of the near optical axis region of the fourth lens is convex; a fifth lens with refractive power, the object side surface of the near circumferential region of the fifth lens is concave, the image side surface of the near circumferential region of the fifth lens is convex, and both the object side surface and the image side surface of the fifth lens are aspherical surfaces; a sixth lens with refractive power, the object side surface of the near circumferential region of the sixth lens is concave, the image side surface of the near circumferential region of the sixth lens is convex, and 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; a seventh lens with negative refractive power, the object side surface of the near optical axis region of the seventh lens is convex, the image side surface of the near optical axis region of the seventh lens is concave, and both the object side surface and the image side surface of the seventh lens are aspherical surfaces, and at least one of the object side surface and the image side surface of the seventh lens is provided with at least one inflection point; The optical system satisfies the condition formula: 0.50≤(CT4+T45) / (CT5+CT6)≤0.81; wherein CT4 is the thickness of the fourth lens on the optical axis, T45 is the distance between the fourth lens and the fifth lens on the optical axis, CT5 is the thickness of the fifth lens on the optical axis, and CT6 is the thickness of the sixth lens on the optical axis.

2. The optical system of claim 1, wherein, The optical system satisfies the condition formula: 1.4≤f / EPD≤2.0; wherein f is the effective focal length of the optical system, and EPD is the entrance pupil diameter of the optical system.

3. The optical system of claim 1, wherein, The optical system satisfies the condition formula: 1.3<TTL / ImgH<1.7; wherein TTL is the distance from the object side surface of the first lens to the imaging surface on the optical axis, and ImgH is half of the diagonal line length of the effective pixel region on the imaging surface.

4. The optical system of claim 1, wherein, The optical system satisfies the condition formula: 0.9<SD11 / SD31<1.3; wherein SD11 is the effective half aperture of the object side surface of the first lens, and SD31 is the effective half aperture of the object side surface of the third lens.

5. The optical system of claim 1, wherein, The optical system satisfies the condition formula: |f / f4|≤0.30; wherein f is the effective focal length of the optical system, and f4 is the effective focal length of the fourth lens.

6. The optical system of claim 1, wherein, The optical system satisfies the condition formula: |f6 / R61|<10.0; wherein f6 is the effective focal length of the sixth lens, and R61 is the curvature radius of the near optical axis region of the object side surface of the sixth lens.

7. The optical system of claim 1, wherein, The optical system satisfies the condition formula: 0.22≤|R71-R72| / |R71+R72|<0.8; R71 is a curvature radius of a region near an optical axis of an object side surface of the seventh lens, and R72 is a curvature radius of a region near an optical axis of an image side surface of the seventh lens.

8. The optical system of claim 1, wherein, The optical system satisfies a conditional expression: R22 / R31 < 1.3; R22 is a curvature radius of a region near an optical axis of an image side surface of the second lens, and R31 is a curvature radius of a region near an optical axis of an object side surface of the third lens.

9. A lens module, characterized by, The electronic device comprises a housing and the lens module as claimed in claim 9, and the lens module is arranged in the housing.

10. An electronic device, comprising: The electronic device comprises a housing and the lens module as claimed in claim 9, and the lens module is arranged in the housing.

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