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 sequentially includes, from the object side to the image side along the optical axis direction: a first lens with negative optical power; a second lens with positive optical power; a third lens with negative optical power; a fourth lens and a fifth lens with optical power; and at least one inflection point is provided on the image side surface of the fifth lens at the optical axis. The optical system satisfies the conditional expressions: 1.1 < tanHFOV / SD1 < 1.8 and 1.7 < TL / ImgH < 2.2. By reasonably setting the surface types and optical powers of the first lens to the fifth lens, and setting an appropriate ratio of tanHFOV / SD1, while maintaining a wide viewing angle, the aperture of the first lens will not increase excessively, which is beneficial to the miniaturization of the system; setting an appropriate ratio of TL / ImgH is beneficial to the compression of the total length of the system, and realizes an ultra-thin design while maintaining high resolution.

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] In recent years, with the development of portable electronic devices such as smart phones and tablet computers and the popularity of online communities, more and more people like to take pictures or selfies and share them with others, and the demand for shooting angles is increasing. A wide-angle lens can expand the shooting field of view and take panoramic or large-scale pictures within a limited distance range.

[0003] However, for a general wide-angle camera lens, due to its characteristics of a large field of view angle and a large relative aperture, the total length of the lens group is often relatively long, making it difficult to be mounted on ultra-thin electronic products. At the same time, with the development of CMOS chip technology, the pixel size of the chip is getting smaller and smaller, and the imaging quality requirements for the matching optical system are getting higher and higher, making it difficult to meet the requirements of a high-pixel photosensitive chip. Summary of the Invention

[0004] The purpose of the present invention is to provide an optical system that meets the requirements of miniaturized structure and large viewing angle.

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

[0006] In a first aspect, the present invention provides an optical system, which has five refractive lenses. Along the optical axis direction from the object side to the image side, it sequentially includes: a first lens with a negative optical power, the object side surface of the first lens at the optical axis is concave, and the object side surface at the circumference is convex, and the image side surface of the first lens at the optical axis is concave; a second lens with a positive optical power, the object side surface of the second lens at the optical axis is convex, and the image side surface at the optical axis is convex; a third lens with a negative optical power, the image side surface of the third lens at the optical axis is concave; a fourth lens with an optical power, the image side surface of the fourth lens at the optical axis is convex; a fifth lens with an optical power, the image side surface of the fifth lens at the optical axis is concave, and at least one inflection point is provided on the image side surface of the fifth lens at the optical axis. The optical system satisfies the following conditional expressions: 1.1 < tanHFOV / SD1 < 1.8; where HFOV is half of the maximum field of view angle of the optical system, and SD1 is the maximum effective semi-aperture of the object side surface of the first lens; and 1.7 < TL / ImgH < 2.2; where TL is the distance on the optical axis from the object side surface of the first lens to the imaging surface of the optical system, and ImgH is half of the diagonal length of the effective pixel area of the optical system. By reasonably setting the surface shapes and optical powers of the first lens to the fifth lens, it is ensured that the optical system meets the requirements of miniaturization, high resolution, and large viewing angle. When the value of tanHFOV / SD1 is lower than the lower limit, the aperture of the first lens of the system becomes larger, resulting in the enlargement of the entire module; when the value of tanHFOV / SD1 is higher than the upper limit, the aperture of the first lens is excessively compressed, which is not conducive to the entry of light rays with a large viewing angle into the camera lens. Reasonably setting the value of tanHFOV / SD1 can maintain a wide viewing angle while preventing the aperture of the first lens from increasing excessively, which is beneficial to the miniaturization of the system. When the value of TL / ImgH is higher than the upper limit, the length of the system becomes longer, resulting in an increase in the height of the module; when the value of TL / ImgH is lower than the lower limit, the system is excessively compressed, and the aberration correction is also insufficient, making it difficult to achieve a high resolution. Setting an appropriate ratio of TL / ImgH is beneficial to the compression of the total length of the system and realizes an ultra-thin design.

[0007] In an implementation manner, the optical system satisfies the following conditional expression: -5 < f5 / f1 < 7; where f1 is the effective focal length of the first lens, and f5 is the effective focal length of the fifth lens. Setting the first lens with a negative optical power enables incident light rays at a larger angle to enter the system, which is beneficial for wide-angleization; at the same time, reasonably configuring the optical power of the fifth lens can correct the system aberration, improve the image quality, and ensure a sufficient back focal length, which is beneficial for the assembly and cooperation of the electronic photosensitive element and improves the yield.

[0008] In one embodiment, the optical system satisfies the following conditional formula: 0.4 < SD1 / ImgH < 0.7. By reasonably setting the ratio of SD1 / ImgH, the system can have a larger aperture to ensure the light passing amount, and the size of the head of the system can be maintained without excessive increase.

[0009] In one embodiment, the optical system satisfies the following conditional formula: 0.16 < T12 / OAL < 0.26; where T12 is the distance on the optical axis from the image side of the first lens to the object side of the second lens, and OAL is the distance on the optical axis from the object side of the first lens to the image side of the fifth lens. When the value of T12 / OAL is lower than the lower limit, the air gap between the lenses is compressed, and the shape of the first lens will be insufficient, which is not conducive to wide-angleization; when the value of T12 / OAL is higher than the upper limit, the system has a large gap and insufficient thinning. By reasonably configuring the value of T12 / OAL, the maximum field of view angle of this wide-angle lens group can be effectively increased.

[0010] In one embodiment, the optical system satisfies the following conditional formula: -3 < R1 / R2 ≤ -0.261, where R1 is the curvature radius of the object side of the first lens and R2 is the curvature radius of the image side of the first lens. By setting the first lens near the optical axis to a biconcave shape, the first lens has a sufficient negative optical power, realizing wide-angleization.

[0011] In one embodiment, the optical system satisfies the following conditional formula: -6 < R3 / R4 < -2, where R3 is the curvature radius of the object side of the second lens and R4 is the curvature radius of the image side of the second lens. By setting the second lens near the optical axis to a biconvex shape, it is beneficial to converge the light rays and realize the shortening of the overall length.

[0012] In one embodiment, the optical system satisfies the following conditional formula: 2 < (CT2 + CT3) / CT1 < 4; where CT1 is the central thickness of the first lens on the optical axis, CT2 is the central thickness of the second lens on the optical axis, and CT3 is the central thickness of the third lens on the optical axis. By reasonably configuring the above thicknesses, the length of the lens can be further shortened, and the first lens is easier to form, reducing the cost.

[0013] In one embodiment, the optical system satisfies the following conditional formula: 1 ≤ V1 / V5 < 2.5; where V1 is the dispersion coefficient of the first lens and V5 is the dispersion coefficient of the fifth lens. By reasonably setting the ratio of V1 / V5, the chromatic aberration of this wide-angle lens can be reduced and the resolution can be improved.

[0014] In one embodiment, the optical system satisfies the following conditional formula: -1 < f2 / f3 < 0; where f2 is the effective focal length of the second lens and f3 is the effective focal length of the third lens. The second lens provides a strong positive optical power, which is beneficial to the development of the ultra-thin wide-angle lens; the third lens provides a negative optical power, which can correct the aberration generated by the second lens and improve the resolution. Through the reasonable configuration of the focal length ratio of the two lenses, while being beneficial to the ultra-thinning of the optical system, it can also correct the aberration generated by the second lens and improve the resolution.

[0015] In a second aspect, the present invention further provides a lens module, including a lens barrel and the optical system according to any one of the first aspect, and the first lens to the fifth lens of the optical system are installed in the lens barrel. By installing each lens of the optical system, the lens module can meet the characteristics of miniaturization and large-angle shooting.

[0016] In a third aspect, the present invention further provides an electronic device, including a housing, an electronic photosensitive element, and the lens module according to the second aspect. The lens module and the electronic photosensitive element are arranged in the housing, and the electronic photosensitive element is arranged on the imaging surface of the optical system for converting the light of the object incident on the electronic photosensitive element through the first lens to the fifth lens into an electrical signal of an image. By providing the lens module of the present invention, the electronic device can achieve thin, light and miniaturization, and can perform large-angle shooting. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

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

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

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

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

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

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

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

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

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

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

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

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

[0030] Figure 7a is a schematic structural diagram of the optical system of the seventh embodiment;

[0031] Figure 7b are the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the seventh embodiment. Detailed implementation manners

[0032] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0033] An embodiment of the present invention provides a lens module, including a lens barrel and the optical system provided by the embodiment of the present invention. The first lens to the fifth lens of the optical system are installed in the lens barrel. This lens module can be an independent lens of a digital camera or an imaging module integrated on an electronic device such as a smart phone. By installing each lens of the optical system, the lens module has the characteristics of miniaturization and large-angle shooting.

[0034] An embodiment of the present invention further provides an electronic device, which includes a housing, an electronic photosensitive element, and the lens module provided by the embodiment of the present invention. The lens module and the electronic photosensitive element are disposed in the housing. The electronic photosensitive element is disposed on the imaging surface of the optical system and is configured to convert the light of an object incident on the electronic photosensitive element through the first lens to the fifth 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 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 dash cam, a wearable device, etc. By providing the lens module of the present invention, the electronic device can achieve thinness, lightness, and miniaturization, and can perform large-angle shooting.

[0035] An embodiment of the present invention provides an optical system including, for example, an optical system composed of five lenses, namely, a first lens, a second lens, a third lens, a fourth lens, and a fifth lens. The first lens to the fifth lens are sequentially disposed from the object side to the image side along the optical axis direction. Among the first lens to the fifth lens, an air gap may be provided between any two adjacent lenses.

[0036] Specifically, the specific shapes and structures of the five lenses are as follows:

[0037] The first lens has a negative focal power. The object side surface of the first lens at the optical axis is concave, and the object side surface at the circumference is convex. The image side surfaces of the first lens at the optical axis and at the circumference are both concave. The second lens has a positive focal power. The object side surfaces of the second lens at the optical axis and at the circumference are both convex, and the image side surfaces at the optical axis and at the circumference are both convex. The third lens has a negative focal power, and the image side surface of the third lens at the optical axis is concave. The fourth lens has a focal power, and the image side surface of the fourth lens at the optical axis is convex. The fifth lens has a focal power. The object side surface of the fifth lens at the circumference is concave. The image side surface of the fifth lens at the optical axis is concave, and the image side surface at the circumference is convex. And at least one inflection point is provided on the image side surface of the fifth lens at the optical axis.

[0038] The optical system further includes a diaphragm. The diaphragm can be disposed at any position between the first lens to the fifth lens, such as between the first lens and the second lens, etc.

[0039] The optical system satisfies the following conditional expressions:

[0040] 1.1 < tanHFOV / SD1 < 1.8; where HFOV is half of the maximum field of view angle of the optical system, and SD1 is the maximum effective semi-aperture of the object side surface of the first lens. And

[0041] 1.7 < TL / ImgH < 2.2, where TL is the distance from the object side of the first lens to the imaging surface of the optical system on the optical axis, and ImgH is half of the diagonal length of the effective pixel area of the optical system.

[0042] The surface shapes and optical powers of the first lens to the fifth lens are reasonably set to ensure that the optical system meets the requirements of miniaturization, high resolution, and large viewing angle. At the same time, setting an appropriate ratio of tanHFOV / SD1 can maintain a wide viewing angle while preventing the aperture of the first lens from increasing excessively, which is beneficial to the miniaturization of the system. Setting an appropriate ratio of TL / ImgH is conducive to compressing the total length of the optical system and achieving an ultra-thin design.

[0043] If tanHFOV / SD1 ≤ 1.1, the aperture of the first lens becomes larger, resulting in an increase in the structure of the entire optical system. If tanHFOV / SD1 ≥ 1.8, the aperture of the first lens is excessively compressed, which is not conducive to light rays with a large viewing angle entering the optical system.

[0044] If TL / ImgH ≤ 1.7, the optical system is excessively compressed, and aberration correction is insufficient, making it difficult to achieve a high resolution. If TL / ImgH ≥ 2.2, the total length of the optical system becomes longer, resulting in an increase in the structure and making it difficult to achieve miniaturization.

[0045] In one embodiment, the optical system satisfies the following conditional formula: -5 < f5 / f1 < 7, where f1 is the effective focal length of the first lens and f5 is the effective focal length of the fifth lens. The first lens provides a negative optical power, enabling incident light rays at a larger angle to enter the optical system, which is beneficial to a wide viewing angle design. Reasonably configuring the optical power of the fifth lens can correct the system aberration, improve the image quality, and at the same time ensure a sufficient back focal length, which is beneficial to the assembly and cooperation of the electronic photosensitive element and improves the yield.

[0046] In one embodiment, the optical system satisfies the following conditional formula: 0.4 < SD1 / ImgH < 0.7; SD1 is the maximum effective semi-aperture of the object side of the first lens; ImgH is half of the diagonal length of the effective pixel area of the optical system. This can not only ensure a relatively large aperture of the optical system to guarantee the light transmission amount but also maintain that the head of the system does not increase excessively.

[0047] In one embodiment, the optical system satisfies the following conditional formula: 0.16 < T12 / OAL < 0.26; where T12 is the distance on the optical axis from the image side surface of the first lens to the object side surface of the second lens, and OAL is the distance on the optical axis from the object side surface of the first lens to the image side surface of the fifth lens. If T12 / OAL ≤ 0.16, the spacing between the lenses will be compressed, and the shape of the first lens cannot be effectively realized, which is not conducive to the wide-angle design. If T12 / OAL ≥ 0.26, the gap of the optical system is large, and the ultra-thinning is insufficient, which is not conducive to the miniaturization of the structure. Reasonably configuring the value of T12 / OAL can effectively increase the maximum field of view angle of this wide-angle lens group.

[0048] In one embodiment, the optical system satisfies the following conditional formula: -3 < R1 / R2 ≤ -0.261; where R1 is the curvature radius of the object side surface of the first lens, and R2 is the curvature radius of the image side surface of the first lens. By setting the first lens near the optical axis to a biconcave shape, the first lens has a sufficient negative optical power, achieving wide-angleization.

[0049] In one embodiment, the optical system satisfies the following conditional formula: -6 < R3 / R4 < -2, where R3 is the curvature radius of the object side surface of the second lens, and R4 is the curvature radius of the image side surface of the second lens. By setting the second lens near the optical axis to a biconvex shape, it is beneficial to converge the light rays and achieve the shortening of the overall length.

[0050] In one embodiment, the optical system satisfies the following conditional formula: 2 < (CT2 + CT3) / CT1 < 4; where CT1 is the central thickness of the first lens on the optical axis, CT2 is the central thickness of the second lens on the optical axis, and CT3 is the central thickness of the third lens on the optical axis. When the above thickness configuration is satisfied, the length of the optical system can be further shortened, and it is easier to mold the first lens, reducing the cost.

[0051] In one embodiment, the optical system satisfies the following conditional formula: 1 ≤ V1 / V5 < 2.5; where V1 is the dispersion coefficient of the first lens, and V5 is the dispersion coefficient of the fifth lens. When V1 / V5 satisfies the above relational formula, the chromatic aberration of this optical system can be reduced, and the resolution can be improved.

[0052] In one embodiment, the optical system satisfies the following conditional formula: -1 < f2 / f3 < 0; where f2 is the effective focal length of the second lens, and f3 is the effective focal length of the third lens. The second lens provides a strong positive optical power, which is beneficial to the ultra-thin design of the optical system. The third lens provides a negative optical power, which can correct the aberration generated by the second lens and improve the resolution ability.

[0053] First Embodiment

[0054] Please refer to Figure 1a and Figure 1b, the optical system of this embodiment successively includes, from the object side to the image side along the optical axis direction:

[0055] The first lens L1 has a negative optical power. The object side surface S1 of the first lens L1 at the optical axis is concave, and the object side surface S1 at the circumference is convex. The image side surface S2 of the first lens L1 is concave;

[0056] The second lens L2 has a positive optical power. The object side surface S3 of the second lens L2 is convex, and the image side surface S4 of the second lens L2 is convex;

[0057] The third lens L3 has a negative optical power. The object side surface S5 of the third lens L3 at the optical axis is convex, and the object side surface S5 at the circumference is concave. The image side surface S6 of the third lens L3 is concave;

[0058] The fourth lens L4 has a positive optical power. The object side surface S7 of the fourth lens L4 is concave, and the image side surface S8 of the fourth lens L4 is convex;

[0059] The fifth lens L5 has a negative optical power. The object side surface S9 of the fifth lens L5 at the optical axis is convex, and the object side surface S9 at the circumference is concave; The image side surface S10 of the fifth lens L5 at the optical axis is concave, and the image side surface S10 at the circumference is convex.

[0060] The materials of the above-mentioned first lens L1 to fifth lens L5 are all plastic.

[0061] In addition, the optical system further includes a diaphragm STO, an infrared cut-off filter L6, and an imaging surface S13. The diaphragm STO is arranged between the first lens L1 and the second lens L2 and is adjacent to the second lens L2, and is used to control the amount of incident light. In other embodiments, the diaphragm STO can also be arranged between other adjacent two lenses. The infrared cut-off filter L6 is arranged on the image side of the fifth lens L5, and it includes an object side surface S11 and an image side surface S12. The infrared cut-off filter L6 is used to filter out infrared light so that the light incident on the imaging surface S13 is visible light, and the wavelength of the visible light is 380nm - 780nm. The material of the infrared cut-off filter L6 is glass, and a film can be coated on the glass. The imaging surface S13 is the effective pixel area of the electronic photosensitive element.

[0062] Table 1a shows a table of the characteristics of the optical system of this embodiment, and the data therein are obtained with light having a wavelength of 555nm. The units of the Y radius, thickness, and focal length are all millimeters (mm).

[0063] Table 1a

[0064]

[0065] Among them, EFL is the effective focal length of the optical system, FNO is the f-number of the optical system, HFOV is half of the maximum field of view angle of the optical system, and TL is the distance from the object side surface of the first lens to the imaging surface of the optical system on the optical axis.

[0066] In this embodiment, the object side surface and the image side surface of any one of the first lens L1 to the fifth lens L5 are aspherical surfaces. The surface shape x of each aspherical lens can be defined by, but not limited to, the following aspherical formula:

[0067]

[0068] Among them, x is the sagitta, the distance from the vertex of the aspherical surface when the aspherical surface is at a position with a height of h along the optical axis direction; c is the paraxial curvature of the aspherical surface, c = 1 / R (that is, 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, A15, A17, and A18 that can be used for each aspherical mirror surface S1 - S10 in the first embodiment.

[0069] Table 1b

[0070]

[0071]

[0072] 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 curvature of the meridional image plane and the sagittal image plane; the distortion curve represents the distortion magnitude values 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.

[0073] Second Embodiment

[0074] Please refer to Figure 2a and Figure 2b , the optical system of this embodiment sequentially includes, from the object side to the image side along the optical axis direction:

[0075] The first lens L1, having a negative optical power, the object side surface S1 of the first lens L1 is concave at the optical axis and convex at the circumference, and the image side surface S2 of the first lens L1 is concave;

[0076] The second lens L2, having a positive optical power, the object side surface S3 of the second lens L2 is convex, and the image side surface S4 of the third lens L2 is convex;

[0077] The third lens L3 has a negative optical power. The object side S5 of the third lens L3 is convex, and the image side S6 of the third lens L3 is concave;

[0078] The fourth lens L4 has a positive optical power. The object side S7 of the fourth lens L4 at the optical axis is concave, and the object side S7 at the circumference is convex. The image side S8 of the fourth lens L4 is convex;

[0079] The fifth lens L5 has a positive optical power. The object side S9 of the fifth lens L5 at the optical axis is convex, and the object side S9 at the circumference is concave; the image side S10 of the fifth lens L5 at the optical axis is concave, and the image side S10 at the circumference is convex.

[0080] The other structures of the second embodiment are the same as those of the first embodiment, and can be referred to.

[0081] Table 2a 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).

[0082] Table 2a

[0083]

[0084] Among them, the meanings of the parameters in Table 2a are the same as those of the parameters in the first embodiment.

[0085] Table 2b gives the higher-order term coefficients of each aspherical lens that can be used in the second embodiment. Among them, each aspherical surface type can be defined by the formula given in the first embodiment.

[0086] Table 2b

[0087]

[0088]

[0089] Figure 2b Shows the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system of the second 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 2b It can be seen that the optical system given in the second embodiment can achieve good imaging quality.

[0090] Third Embodiment

[0091] 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:

[0092] The first lens L1 has a negative optical power. The object side surface S1 of the first lens L1 at the optical axis is concave, and the object side surface S1 at the circumference is convex. The image side surface S2 of the first lens L1 is concave;

[0093] The second lens L2 has a positive optical power. The object side surface S3 of the second lens L2 is convex, and the image side surface S4 of the third lens L2 is convex;

[0094] The third lens L3 has a negative optical power. The object side surface S5 of the third lens L3 is concave, and the image side surface S6 of the third lens L3 at the optical axis is concave, and the image side surface S6 at the circumference is convex;

[0095] The fourth lens L4 has a positive optical power. The object side surface S7 of the fourth lens L4 is concave, and the image side surface S8 of the fourth lens L4 is convex;

[0096] The fifth lens L5 has a negative optical power. The object side surface S9 of the fifth lens L5 at the optical axis is convex, and the object side surface S9 at the circumference is concave; The image side surface S10 of the fifth lens L5 at the optical axis is concave, and the image side surface S10 at the circumference is convex.

[0097] The other structures of the third embodiment are the same as those of the first embodiment, and can be referred to.

[0098] Table 3a shows a table of the characteristics of the optical system of this embodiment, and the data therein are obtained with light rays having a wavelength of 587.6 nm. The units of the Y radius, thickness, and focal length are all millimeters (mm).

[0099] Table 3a

[0100]

[0101] Among them, the meanings of the parameters in Table 3a are the same as those of the parameters in the first embodiment.

[0102] Table 3b gives the higher-order term coefficients of each aspherical lens that can be used in the third embodiment. Among them, each aspherical surface type can be defined by the formula given in the first embodiment.

[0103] Table 3b

[0104]

[0105]

[0106] Figure 3bThe longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system of the third embodiment are shown. Among them, the longitudinal spherical aberration curve represents the deviation of the 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 3b it can be known that the optical system given in the third embodiment can achieve good imaging quality.

[0107] Fourth Embodiment

[0108] 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:

[0109] The first lens L1 has a negative optical power. The object side surface S1 of the first lens L1 at the optical axis is concave, and the object side surface S1 at the circumference is convex. The image side surface S2 of the first lens L1 is concave;

[0110] The second lens L2 has a positive optical power. The object side surface S3 of the second lens L2 is convex, and the image side surface S4 of the third lens L2 is convex;

[0111] The third lens L3 has a negative optical power. The object side surface S5 of the third lens L3 is concave, and the image side surface S6 of the third lens L3 is concave;

[0112] The fourth lens L4 has a positive optical power. The object side surface S7 of the fourth lens L4 is convex, and the image side surface S8 of the fourth lens L4 is convex;

[0113] The fifth lens L5 has a negative optical power. The object side surface S9 of the fifth lens L5 is concave; the image side surface S10 of the fifth lens L5 at the optical axis is concave, and the image side surface S10 at the circumference is convex.

[0114] The other structures of the fourth embodiment are the same as those of the first embodiment, and can be referred to accordingly.

[0115] Table 4a shows a table of the characteristics of the optical system of this embodiment, where the data are obtained with light rays of a wavelength of 555 nm. The units of the Y radius, thickness, and focal length are all millimeters (mm).

[0116] Table 4a

[0117]

[0118]

[0119] Among them, the meanings of the parameters in Table 4a are the same as those of the parameters in the first embodiment.

[0120] Table 4b shows the higher-order term coefficients of the aspherical lenses that can be used in the fourth embodiment. Among them, each aspherical surface type can be defined by the formula given in the first embodiment.

[0121] Table 4b

[0122]

[0123] Figure 4b shows the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system of the fourth 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 4b it can be seen that the optical system given in the fourth embodiment can achieve good imaging quality.

[0124] Fifth Embodiment

[0125] 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:

[0126] The first lens L1 has a negative optical power. The object side surface S1 of the first lens L1 at the optical axis is concave, and the object side surface S1 at the circumference is convex. The image side surface S2 of the first lens L1 is concave;

[0127] The second lens L2 has a positive optical power. The object side surface S3 of the second lens L2 is convex, and the third lens L2's image side surface S4 is convex;

[0128] The third lens L3 has a negative optical power. The object side surface S5 of the third lens L3 is concave, and the image side surface S6 of the third lens L3 is concave;

[0129] The fourth lens L4 has a positive optical power. The object side surface S7 of the fourth lens L4 at the optical axis is concave, and the object side surface S7 at the circumference is convex. The image side surface S8 of the fourth lens L4 is convex;

[0130] The fifth lens L5 has a negative optical power. The object side surface S9 of the fifth lens L5 at the optical axis is convex, and the object side surface S9 at the circumference is concave; the image side surface S10 of the fifth lens L5 at the optical axis is concave, and the image side surface S10 at the circumference is convex.

[0131] The other structures of the fifth embodiment are the same as those of the first embodiment, and can be referred to.

[0132] Table 5a shows a table of the characteristics of the optical system of this embodiment, where the data is obtained using light rays with a wavelength of 587.6 nm. The units of the Y radius, thickness, and focal length are all millimeters (mm).

[0133] Table 5a

[0134]

[0135] Among them, the meanings of the parameters in Table 5a are the same as those of the parameters in the first embodiment. Table 5b gives the higher-order term coefficients of the aspherical lenses that can be used in the fifth embodiment. Among them, each aspherical surface type can be defined by the formula given in the first embodiment.

[0136] Table 5b

[0137]

[0138] Figure 5b Shows the longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the fifth embodiment. Among them, the longitudinal spherical aberration curve represents the deviation of the convergence points of the light rays of different wavelengths after passing through each lens of the optical system; the astigmatism curve represents the meridional image plane curvature and the sagittal image plane curvature; the distortion curve represents the distortion magnitude values corresponding to different field angles. According to Figure 5b It can be known that the optical system given in the fifth embodiment can achieve good imaging quality.

[0139] Sixth Embodiment

[0140] 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:

[0141] The first lens L1 has a negative optical power. The object side surface S1 of the first lens L1 at the optical axis is concave, and the object side surface S1 at the circumference is convex. The image side surface S2 of the first lens L1 is concave;

[0142] The second lens L2 has a positive optical power. The object side surface S3 of the second lens L2 is convex, and the image side surface S4 of the third lens L2 is convex;

[0143] The third lens L3 has a negative optical power. The object side surface S5 of the third lens L3 at the optical axis is convex, and the object side surface S5 at the circumference is concave. The image side surface S6 of the third lens L3 is concave;

[0144] The fourth lens L4 has a negative optical power. The object side surface S7 of the fourth lens L4 is concave, and the image side surface S8 of the fourth lens L4 is convex;

[0145] The fifth lens L5 has a positive optical power. The object side surface S9 of the fifth lens L5 at the optical axis is convex, and the object side surface S9 at the circumference is concave; the image side surface S10 of the fifth lens L5 at the optical axis is concave, and the image side surface S10 at the circumference is convex.

[0146] The other structures of the sixth embodiment are the same as those of the first embodiment, and can be referred to accordingly.

[0147] Table 6a shows a table of the characteristics of the optical system of this embodiment, and the data in it are obtained with light rays having a wavelength of 587.6 nm. The units of the Y radius, thickness, and focal length are all millimeters (mm).

[0148] Table 6a

[0149]

[0150] Among them, the meanings of the parameters in Table 6a are the same as those of the parameters in the first embodiment. Table 6b gives the higher-order term coefficients of each aspherical lens that can be used in the sixth embodiment. Among them, each aspherical surface type can be defined by the formula given in the first embodiment.

[0151] Table 6b

[0152]

[0153]

[0154] Figure 6b Shows the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the optical system of the sixth 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 6b It can be known that the optical system given in the sixth embodiment can achieve good imaging quality.

[0155] Seventh embodiment

[0156] Please refer to Figure 7a and Figure 7b , the optical system of this embodiment sequentially includes, from the object side to the image side along the optical axis direction:

[0157] The first lens L1 has a negative optical power. The object side surface S1 of the first lens L1 at the optical axis is concave, and the object side surface S1 at the circumference is convex. The image side surface S2 of the first lens L1 is concave;

[0158] The second lens L2 has a positive optical power. The object side surface S3 of the second lens L2 is convex, and the third lens L2's image side surface S4 is convex;

[0159] The third lens L3 has a negative optical power. The object side surface S5 of the third lens L3 at the optical axis is convex, and the object side surface S5 at the circumference is concave. The image side surface S6 of the third lens L3 is concave;

[0160] The fourth lens L4 has a positive optical power. The object side surface S7 of the fourth lens L4 is convex, the image side surface S8 at the optical axis of the fourth lens L4 is convex, and the image side surface S8 at the circumference is concave;

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

[0162] The other structures of the seventh embodiment are the same as those of the first embodiment, and can be referred to accordingly.

[0163] Table 7a shows a table of the characteristics of the optical system of this embodiment, where the data are obtained with light rays of a wavelength of 587.6 nm, and the units of the Y radius, thickness, and focal length are all millimeters (mm).

[0164] Table 7a

[0165]

[0166] Among them, the meanings of the parameters in Table 7a are the same as those of the parameters in the first embodiment. Table 7b gives the higher-order term coefficients of the aspherical lenses that can be used in the seventh embodiment. Among them, the aspherical surface types can be defined by the formulas given in the first embodiment.

[0167] Table 7b

[0168]

[0169]

[0170] 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 the lenses 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.

[0171] Table 8 shows the values of TL / ImgH, tanHFOV / SD1, f5 / f1, SD1 / ImgH, T12 / OAL, R1 / R2, R3 / R4, (CT2 + CT3) / CT1, V1 / V5, and f2 / f3 of the optical systems of the first to seventh embodiments. It can be seen from Table 8 that each embodiment satisfies the conditions: 1.7 < TL / ImgH < 2.2, 1.1 < tanHFOV / SD1 < 1.8, -5 < f5 / f1 < 7, 0.4 < SD1 / ImgH < 0.7, 0.16 < T12 / OAL < 0.26, -3 < R1 / R2 ≤ -0.261, -6 < R3 / R4 < -2, 2 < (CT2 + CT3) / CT1 < 4, 1 ≤ V1 / V5 < 2.5, and -1 < f2 / f3 < 0.

[0172] Table 8

[0173]

[0174]

[0175] What is disclosed above is only a preferred embodiment of the present invention. Of course, the scope of the rights of the present invention cannot be limited thereby. Those of ordinary skill in the art can understand all 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 in that, it has a total of five refractive lenses, which successively include from the object side to the image side along the optical axis direction: The first lens, which has a negative optical power, the object side surface of the first lens at the optical axis is concave, the object side surface at the circumference is convex, and the image side surface of the first lens at the optical axis is concave; The second lens, which has a positive optical power, the object side surface of the second lens at the optical axis is convex, and the image side surface at the optical axis is convex; The third lens, which has a negative optical power, the image side surface of the third lens at the optical axis is concave; The fourth lens, which has an optical power, the image side surface of the fourth lens at the optical axis is convex; The fifth lens, which has an optical power, the image side surface of the fifth lens at the optical axis is concave, and at least one inflection point is provided on the image side surface of the fifth lens at the optical axis; The optical system satisfies the following conditional expressions: 1.1 < tanHFOV / SD1 < 1.8; wherein, HFOV is half of the maximum field of view angle of the optical system, and SD1 is the maximum effective semi-aperture of the object side surface of the first lens; 1.7 < TL / ImgH < 2.2; wherein, TL is the distance on the optical axis from the object side surface of the first lens to the imaging surface of the optical system, and ImgH is half of the diagonal length of the effective pixel region of the optical system; and -3 < R1 / R2 ≤ -0.261; wherein, R1 is the curvature radius of the object side surface of the first lens, and R2 is the curvature radius of the image side surface of the first lens.

2. The optical system according to claim 1, characterized in that, the optical system satisfies the following conditional expression: -5 < f5 / f1 < 7; wherein, f1 is the effective focal length of the first lens, and f5 is the effective focal length of the fifth lens.

3. The optical system according to claim 1, characterized in that, the optical system satisfies the following conditional expression: 0.4 < SD1 / ImgH < 0.

7.

4. The optical system according to claim 1, characterized in that, the optical system satisfies the following conditional expression: 0.16 < T12 / OAL < 0.26; wherein, T12 is the distance on the optical axis from the image side surface of the first lens to the object side surface of the second lens, and OAL is the distance on the optical axis from the object side surface of the first lens to the image side surface of the fifth lens.

5. The optical system according to claim 1, characterized in that, the optical system satisfies the following conditional expression: -6 < R3 / R4 < -2; where R3 is the curvature radius of the object side surface of the second lens, and R4 is the curvature radius of the image side surface of the second lens.

6. The optical system according to claim 1, characterized in that, the optical system satisfies the following conditional expression: 2 < (CT2 + CT3) / CT1 < 4; wherein, CT1 is the central thickness of the first lens on the optical axis, CT2 is the central thickness of the second lens on the optical axis, and CT3 is the central thickness of the third lens on the optical axis.

7. The optical system according to claim 1, characterized in that, the optical system satisfies the following conditional expression: 1 ≤ V1 / V5 < 2.5; Wherein, V1 is the dispersion coefficient of the first lens, and V5 is the dispersion coefficient of the fifth lens.

8. The optical system according to claim 1, characterized in that the optical system satisfies the following conditional formula: -1 < f2 / f3 < 0; wherein, f2 is the effective focal length of the second lens, and f3 is the effective focal length of the third lens.

9. A lens module, characterized in that it includes a lens barrel and the optical system according to any one of claims 1 to 8, and the first lens to the fifth lens of the optical system are installed in the lens barrel.

10. An electronic device, characterized in that it includes a housing, an electronic photosensitive element, and the lens module according to claim 9. The lens module and the electronic photosensitive element are arranged in the housing, and the electronic photosensitive element is arranged on the imaging surface of the optical system and is used to convert the light of an object incident on the electronic photosensitive element through the first lens to the fifth lens into an electrical signal of an image.

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