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, in order from an object side to an image side: a first lens having positive fold power, the object side surface of the first lens being convex at the optical axis; a second lens having negative fold power, the image side surface of the second lens being concave at the optical axis; a third lens having fold power; a fourth lens having fold power; a fifth lens having fold power; and a sixth lens having fold power. The optical system satisfies the condition formula: -2 < f1 / f2345 < -0.5; wherein f1 is the effective focal length of the first lens, and f2345 is the combined focal length of the second lens, the third lens, the fourth lens and the fifth lens. By reasonably configuring the fold power and surface type of each lens, and by simultaneously satisfying the value of f1 / f2345 being between -2 and -0.5, the optical power of the two parts of the optical system can be reasonably distributed, the chromatic aberration of the optical system can be better corrected, and thus the performance of the optical system is improved.

Description

Technical Field

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

[0002] With the wide application of electronic products such as mobile phones, tablet computers, drones, and computers in life, various technological improvements emerge in an endless stream. Among them, the improvement and innovation of the shooting effect of camera lenses in the improvement of new electronic products have become one of the focuses of people's attention and an important part of technological improvement.

[0003] At present, due to the unreasonable distribution of optical power in a six-lens optical system, the chromatic aberration of the optical system is not corrected or not thoroughly corrected, resulting in poor shooting effects of the optical system and low performance of the optical system. Summary of the Invention

[0004] The object of the present invention is to provide an optical system that can well correct the chromatic aberration of the optical system and has good shooting effects.

[0005] To achieve the object 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 sequentially includes, from the object side to the image side: a first lens having a positive refractive power, and the object side surface of the first lens is convex at the optical axis; a second lens having a negative refractive power, and the image side surface of the second lens is concave at the optical axis; a third lens having a refractive power; a fourth lens having a refractive power; a fifth lens having a refractive power; a sixth lens having a refractive power; the optical system satisfies the conditional formula: -2 < f1 / f2345 < -0.5; where f1 is the effective focal length of the first lens, and f2345 is the combined focal length of the second lens, the third lens, the fourth lens, and the fifth lens. By reasonably configuring the refractive powers and surface types of each lens, and simultaneously satisfying that the value of f1 / f2345 is between -2 and -0.5, it helps to reasonably distribute the optical power of the two parts of the optical system, can better correct the chromatic aberration of the optical system, and thus improve the performance of the optical system.

[0007] In an implementation manner, the object side surface and the image side surface of any one of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are aspherical surfaces. By setting the object side surfaces and the image side surfaces of the first lens to the sixth lens as aspherical surfaces, the aberration generated by the optical system is eliminated, which is beneficial to further improving the performance of the optical system.

[0008] In one embodiment, the optical system satisfies the conditional equation: TTL / Imgh < 2.4; where TTL is the distance on the optical axis from the object-side surface of the first lens to the imaging plane of the optical system, and ImgH is half the diagonal length of the effective pixel area on the imaging plane of the optical system. By ensuring that the ratio of TTL to Imgh is within 2.4, the optical system can have a shorter overall length while maintaining a fixed imaging plane, thereby achieving miniaturized design requirements.

[0009] In one embodiment, the optical system satisfies the conditional equation: TTL / f<1.1; wherein TTL is the distance on the optical axis from the object-side surface of the first lens to the imaging plane of the optical system, and f is the effective focal length of the optical system. By ensuring that the ratio of TTL to f is within 1.1, the effective focal length of the optical system has a larger lower limit while maintaining a constant overall system length and miniaturization, thereby meeting the optical system's long focal length requirement.

[0010] In one embodiment, the optical system satisfies the conditional formula: FNO < 2.6, where FNO is the aperture number of the optical system. By ensuring the aperture number of the optical system is within 2.6, the optical system can achieve high light throughput while maintaining the telephoto performance of the lens, allowing the optical system to achieve clear imaging even in dark environments.

[0011] In one embodiment, the optical system satisfies the condition: map2 / map1>0.6; where map2 is the aperture of light passing through the image side of the sixth lens when the optical system's aperture number is maximum, and map1 is the aperture of light passing through the central field of view through the image side of the sixth lens. By ensuring that map2 / map1 is greater than 0.6, the relative brightness of the optical system is improved, enabling clear imaging even in dark environments.

[0012] In one embodiment, the optical system satisfies the following condition: Imgh / tan(HFOV)>6mm; where ImgH is half the diagonal length of the effective pixel area on the imaging plane of the optical system, and HFOV is the half field of view of the optical system. By ensuring that Imgh / tan(HFOV) is greater than 6mm, the optical system's telephoto characteristics are maintained, increasing the imaging magnification.

[0013] In one embodiment, the optical system satisfies the conditional formula: 1.5 < TTL / (ct23 + ct45) < 6; where TTL is the distance on the optical axis from the object side surface of the first lens to the imaging surface of the optical system, ct23 is the distance on the optical axis between the image side surface of the second lens and the object side surface of the third lens, and ct45 is the distance on the optical axis between the image side surface of the fourth lens and the object side surface of the fifth lens. By making the value of TTL / (ct23 + ct45) fall between 1.5 and 6, the third lens and the fourth lens are arranged in a compact manner, becoming the transition part for the system's light ray refraction. As a result, less optical power is distributed, reducing the overall sensitivity of the optical system.

[0014] In one embodiment, the optical system satisfies the conditional formula: (r4 + r1) / (r4 - r1) > 1; where r1 is the curvature radius at the optical axis of the object side surface of the first lens, and r4 is the curvature radius at the optical axis of the image side surface of the second lens. It can be understood that the above two curvature radii mainly perform the function of correcting spherical aberration for the entire system. By making the value of (r4 + r1) / (r4 - r1) greater than 1, the primary aberration of the optical system can be well corrected, thereby improving the performance.

[0015] In a second aspect, the present invention further provides a lens module. The lens module includes a lens barrel, a photosensitive element, and the optical system according to any one of the embodiments in the first aspect. The first lens to the sixth lens of the optical system are installed in the lens barrel, and the photosensitive element is disposed on the image side of the optical system. By incorporating the optical system provided by the present invention into the lens module, the lens module can meet the design requirements of a long focal length, has a high magnification ratio and relative brightness, and can simultaneously well correct the chromatic aberration of the optical system, thereby having excellent shooting performance.

[0016] In a third aspect, the present invention further provides an electronic device. The electronic device includes a housing and the lens module of the second aspect, and the lens module is disposed within the housing. By incorporating the lens module provided by the present invention into the electronic device, the optical system within the working range of the near-infrared band exhibits the characteristics of high resolution and miniaturization, thereby accurately and real-time capturing the information of the driver and transmitting the captured image information to the photosensitive element, achieving real-time monitoring and recognition of the driver. By incorporating the lens module provided by the present invention into the electronic device, the electronic device can meet the design requirements of a long focal length, has a high magnification ratio and relative brightness, and can simultaneously well correct the chromatic aberration of the optical system, thereby having excellent shooting performance. Description of the Drawings

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

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

[0019] Figure 1b 1 are 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 1 and 2 are the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the second embodiment;

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

[0023] Figure 3b 1 and 2 are the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the third embodiment;

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

[0025] Figure 4b 1 and 2 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 1 and 2 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 1 and 2 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 1 and 2 are the longitudinal spherical aberration curve, astigmatism curve, and distortion curve of the seventh embodiment. DETAILED DESCRIPTION

[0032] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] An embodiment of the present invention provides an electronic device, which includes a housing and the lens module of the second aspect, wherein the lens module is arranged in the housing. The electronic device can be a smart phone, a personal digital assistant (PDA), a tablet computer, a smart watch, a drone, an e-book reader, a driving recorder, a wearable device, etc. By adding the lens module provided by the present invention to the electronic device, the optical system within the working range of the near-infrared band exhibits the characteristics of high resolution and miniaturization, thereby accurately and in real time capturing the driver's information, and transmitting the captured image information to the photosensitive element, thereby realizing real-time monitoring and identification of the driver. By adding the lens module provided by the present invention to the electronic device, the electronic device can meet the design requirements of a long focal length, have a high magnification and relative brightness, and at the same time can well correct the chromatic aberration of the optical system, thereby having better shooting performance.

[0034] An embodiment of the present invention provides a lens module, comprising a lens barrel, a photosensitive element, and the optical system described in any one of the embodiments of the first aspect, wherein the first to sixth lenses of the optical system are mounted within the lens barrel, and the photosensitive element is disposed on the image side of the optical system. The photosensitive element is configured to convert light from an object passing through the first to sixth lenses and incident on the photosensitive element into an electrical signal representing an image. The photosensitive element may be a complementary metal oxide semiconductor (CMOS) or a charge-coupled device (CCD). The lens module may be an independent lens of a digital camera, or an imaging module integrated into an electronic device such as a smartphone or tablet computer. By incorporating the optical system provided by the present invention into the lens module, the lens module can meet the design requirements of a long focal length, have a high magnification and relative brightness, and can effectively correct the chromatic aberration of the optical system, thereby achieving superior shooting performance.

[0035] An embodiment of the present invention provides an optical system, comprising, from the object side to the image side, the following components:

[0036] A first lens having positive refractive power, wherein the object-side surface of the first lens is convex at the optical axis;

[0037] A second lens element having negative refractive power, wherein the image-side surface of the second lens element is concave at the optical axis;

[0038] The third lens has a refracting power;

[0039] The fourth lens has a refracting power;

[0040] The fifth lens has a refracting power;

[0041] a sixth lens having a refracting power;

[0042] The optical system satisfies the conditional formula:

[0043] -2 <f1 / f2345<-0.5;

[0044] Wherein, f1 is the effective focal length of the first lens, and f2345 is the combined focal length of the second lens, the third lens, the fourth lens, and the fifth lens.

[0045] By properly configuring the refractive power and surface shape of each lens while ensuring that the f1 / f2345 value is between -2 and -0.5, it helps to properly distribute the optical power of the two parts of the optical system, better correct the chromatic aberration of the optical system, and thus improve the performance of the optical system.

[0046] In one embodiment, the object-side surface and image-side surface of any of the first, second, third, fourth, fifth, and sixth lenses are aspherical. By providing aspherical surfaces for the object-side and image-side surfaces of the first through sixth lenses, aberrations generated by the optical system are eliminated, thereby further improving the performance of the optical system.

[0047] In one embodiment, the optical system satisfies the conditional equation: TTL / Imgh < 2.4; where TTL is the distance on the optical axis from the object-side surface of the first lens to the imaging plane of the optical system, and ImgH is half the diagonal length of the effective pixel area on the imaging plane of the optical system. By ensuring that the ratio of TTL to Imgh is within 2.4, the optical system can have a short overall system length while keeping the imaging plane fixed, thereby achieving miniaturization requirements. Specifically, the value of TTL / Imgh can be 0.1, 0.3, 0.5, 1, 1.5, 2, 2.35, etc.

[0048] In one embodiment, the optical system satisfies the conditional equation: TTL / f < 1.1; where TTL is the distance on the optical axis from the object-side surface of the first lens to the imaging plane of the optical system, and f is the effective focal length of the optical system. By ensuring that the ratio of TTL to f is within 1.1, the effective focal length of the optical system has a large lower limit while maintaining the total system length and miniaturization, thereby meeting the optical system's long focal length requirements. Specifically, the value of TTL / f can be 1.08, 1, 0.85, 0.6, 0.4, 0.15, etc.

[0049] In one embodiment, the optical system satisfies the conditional formula: FNO < 2.6, where FNO is the aperture number of the optical system. By ensuring the aperture number of the optical system is within 2.6, the optical system can achieve high light throughput while maintaining the telephoto performance of the lens, enabling clear imaging even in dark environments. Specifically, FNO values ​​can be 0.1, 0.5, 0.9, 1.2, 1.8, 2.3, 2.5, etc.

[0050] In one embodiment, the optical system satisfies the condition: map2 / map1>0.6; where map2 is the clear aperture of light on the image side of the sixth lens when the optical system's aperture number is maximum, and map1 is the clear aperture of light from the central field of view on the image side of the sixth lens. By ensuring that the map2 / map1 value is greater than 0.6, the relative brightness of the optical system is improved, achieving clear imaging even in dark environments. Specifically, the map2 / map1 value can be 0.62, 0.68, 0.75, 0.9, 1.4, 2.2, etc.

[0051] In one embodiment, the optical system satisfies the following condition: Imgh / tan(HFOV) > 6mm; where ImgH is half the diagonal length of the effective pixel area on the imaging plane of the optical system, and HFOV is the half field of view of the optical system. By ensuring that Imgh / tan(HFOV) is greater than 6mm, the optical system's telephoto characteristics are maintained and the imaging magnification is increased. Specifically, Imgh / tan(HFOV) values ​​can be 6.1mm, 6.5mm, 7mm, 8mm, 9.5mm, and 12mm, among others.

[0052] In one embodiment, the optical system satisfies the conditional formula: 1.5 < TTL / (ct23 + ct45) < 6; where TTL is the distance from the object side surface of the first lens to the imaging surface of the optical system on the optical axis, ct23 is the distance between the image side surface of the second lens and the object side surface of the third lens on the optical axis, and ct45 is the distance between the image side surface of the fourth lens and the object side surface of the fifth lens on the optical axis. By satisfying that the value of TTL / (ct23 + ct45) is between 1.5 and 6, the third lens and the fourth lens are arranged compactly, becoming the transition part of the system for light ray refraction. Thus, less optical power is distributed, reducing the overall sensitivity of the optical system. Specifically, the value of TTL / (ct23 + ct45) can be 1.52, 1.67, 1.83, 2.56, 3.75, 4.25, 5.51, 5.97, etc.

[0053] In one embodiment, the optical system satisfies the conditional formula: (r4 + r1) / (r4 - r1) > 1; where r1 is the radius of curvature of the object side surface of the first lens on the optical axis, and r4 is the radius of curvature of the image side surface of the second lens on the optical axis. It can be understood that the above two radii of curvature mainly perform the function of correcting spherical aberration of the entire system. By satisfying that the value of (r4 + r1) / (r4 - r1) is greater than 1, the first-order aberration of the optical system can be well corrected, thereby improving the performance. Specifically, the value of (r4 + r1) / (r4 - r1) can be 1.2, 1.8, 2.5, 3.5, 5, etc.

[0054] First Embodiment

[0055] Please refer to Figure 1a and Figure 1b , the optical system of this embodiment includes, in sequence from the object side to the image side:

[0056] The first lens L1, having a positive refracting power. The object side surface S1 of the first lens L1 is convex on the optical axis and concave at the circumference; the image side surface S2 of the first lens L1 is convex both on the optical axis and at the circumference;

[0057] The second lens L2, having a negative refracting power. The object side surface S3 of the second lens L2 is convex both on the optical axis and at the circumference; the image side surface S4 of the second lens L2 is concave both on the optical axis and at the circumference;

[0058] The third lens L3, having a negative refracting power. The object side surface S5 of the third lens L3 is concave both on the optical axis and at the circumference; the image side surface S6 of the third lens L3 is convex on the optical axis and concave at the circumference;

[0059] The fourth lens L4 has positive refractive power. The object-side surface S7 of the fourth lens L4 is convex both on the optical axis and on the circumference. The image-side surface S8 of the fourth lens L4 is concave on the optical axis and convex on the circumference.

[0060] The fifth lens L5 has negative refractive power. The object-side surface S9 of the fifth lens L5 is concave both on the optical axis and on the circumference. The image-side surface S10 of the fifth lens L5 is concave on the optical axis and convex on the circumference.

[0061] The sixth lens L6 has positive refractive power. The object-side surface S11 of the sixth lens L6 is convex both at the optical axis and at the circumference. The image-side surface S12 of the sixth lens L6 is concave both at the optical axis and at the circumference.

[0062] The first lens L1 to the sixth lens L6 are all made of plastic.

[0063] In addition, the optical system also includes an aperture STO, an infrared cutoff filter L7, and an imaging surface S15. The aperture STO is arranged between the image side surface S4 of the second lens L2 and the object side surface S5 of the third lens L3, and is used to control the amount of light entering. In other embodiments, the aperture ST0 can also be arranged on the object side or image side surface of the lens. The infrared cutoff filter L7 is arranged on the image side of the sixth lens L6, and includes an object side surface S13 and an image side surface S14. The object side surface S13 of the infrared cutoff filter L7 is opposite to the image side surface S12 of the sixth lens L6. The infrared cutoff filter L7 is used to filter out infrared light so that the light entering the imaging surface S15 is visible light with a wavelength of 380nm-780nm. The material of the infrared cutoff filter L7 is glass, and a film can be coated on the glass. The imaging surface S15 is the effective pixel area of ​​the photosensitive element.

[0064] Table 1a shows the characteristics of the optical system of this embodiment, wherein the data are obtained using light with a wavelength of 587 nm, and the units of Y radius, thickness and focal length are all millimeters (mm).

[0065] Table 1a

[0066]

[0067]

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

[0069] In this embodiment, the object-side surface and the image-side surface of any lens from the first lens L1 to the sixth lens L6 are both aspherical surfaces. The surface shape x of each aspherical lens can be defined by, but is not limited to, the following aspherical surface formula:

[0070]

[0071] Where x is the maximum sag height of the aspheric surface at a height h along the optical axis, from the vertex of the aspheric surface; c is the paraxial curvature of the aspheric surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the Y radius R in Table 1a above); k is the conic coefficient; Ai is the correction coefficient for the i-th order of the aspheric surface. Table 1b lists the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for each aspheric mirror surface S1-S14 in the first embodiment.

[0072] Table 1b

[0073]

[0074]

[0075] Figure 1b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the first embodiment are shown. The reference wavelength of the light of the astigmatism curve and distortion curve is 555nm, among which the longitudinal spherical aberration curve represents the deviation of the focal point of light of different wavelengths after passing through each lens of the optical system; the astigmatism curve represents the meridional image curvature and sagittal image curvature; the distortion curve represents the distortion value corresponding to different field angles. Figure 1b It can be seen that the optical system provided in the first embodiment can achieve good imaging quality.

[0076] Second embodiment

[0077] Please refer to Figure 2a and Figure 2b The optical system of this embodiment includes, from the object side to the image side, the following components:

[0078] The first lens L1 has positive refractive power. The object-side surface S1 of the first lens L1 is convex along the optical axis and concave along the circumference. The image-side surface S2 of the first lens L1 is convex along the optical axis and along the circumference.

[0079] The second lens L2 has negative refractive power. The object-side surface S3 of the second lens L2 is concave along the optical axis and convex along the circumference. The image-side surface S4 of the second lens L2 is concave along the optical axis and convex along the circumference.

[0080] The third lens L3 has negative refractive power. The object-side surface S5 of the third lens L3 is concave both on the optical axis and on the circumference. The image-side surface S6 of the third lens L3 is convex on the optical axis and concave on the circumference.

[0081] The fourth lens L4 has positive refractive power. The object-side surface S7 of the fourth lens L4 is convex both on the optical axis and on the circumference. The image-side surface S8 of the fourth lens L4 is convex on the optical axis and concave on the circumference.

[0082] The fifth lens L5 has negative refractive power. The object-side surface S9 of the fifth lens L5 is concave both on the optical axis and on the circumference. The image-side surface S10 of the fifth lens L5 is concave on the optical axis and convex on the circumference.

[0083] The sixth lens L6 has positive refractive power. The object-side surface S11 of the sixth lens L6 is convex both at the optical axis and at the circumference. The image-side surface S12 of the sixth lens L6 is concave both at the optical axis and at the circumference.

[0084] The other structures of the second embodiment are the same as those of the first embodiment, and can be used as a reference.

[0085] Table 2a shows a table of characteristics of the optical system of this embodiment, wherein the data are obtained using light with a wavelength of 587 nm, and the units of Y radius, thickness and focal length are all millimeters (mm).

[0086] Table 2a

[0087]

[0088] Wherein, f is the effective focal length of the optical system, FNO is the aperture number of the optical system, FOV is the maximum field angle of the optical system in the diagonal direction, and TTL is the distance from the object side of the first lens to the imaging plane of the optical system on the optical axis.

[0089] Table 2b gives the high-order coefficients of each aspherical mirror surface that can be used in the second embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0090] Table 2b

[0091]

[0092]

[0093] Figure 2b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the second embodiment are shown. The reference wavelength of the light of the astigmatism curve and the distortion curve is 555nm. Figure 2b It can be seen that the optical system provided in the second embodiment can achieve good imaging quality.

[0094] Third embodiment

[0095] Please refer to Figure 3a and Figure 3b The optical system of this embodiment includes, from the object side to the image side, the following components:

[0096] The first lens L1 has positive refractive power. The object-side surface S1 of the first lens L1 is convex along the optical axis and concave along the circumference. The image-side surface S2 of the first lens L1 is convex along the optical axis and along the circumference.

[0097] The second lens L2 has negative refractive power. The object-side surface S3 of the second lens L2 is concave along the optical axis and convex along the circumference. The image-side surface S4 of the second lens L2 is concave along the optical axis and convex along the circumference.

[0098] The third lens L3 has negative refractive power. The object-side surface S5 of the third lens L3 is concave both on the optical axis and on the circumference. The image-side surface S6 of the third lens L3 is concave both on the optical axis and on the circumference.

[0099] The fourth lens L4 has negative refractive power. The object-side surface S7 of the fourth lens L4 is concave along the optical axis and convex along the circumference. The image-side surface S8 of the fourth lens L4 is convex along the optical axis and concave along the circumference.

[0100] The fifth lens L5 has negative refractive power. The object-side surface S9 of the fifth lens L5 is concave along the optical axis and convex along the circumference. The image-side surface S10 of the fifth lens L5 is concave along the optical axis and along the circumference.

[0101] The sixth lens L6 has negative refractive power. The object-side surface S11 of the sixth lens L6 is convex both at the optical axis and at the circumference. The image-side surface S12 of the sixth lens L6 is concave both at the optical axis and at the circumference.

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

[0103] Table 3a shows a table of characteristics of the optical system of this embodiment, wherein the data are obtained using light with a wavelength of 587 nm, and the units of Y radius, thickness and focal length are all millimeters (mm).

[0104] Table 3a

[0105]

[0106] Wherein, f is the effective focal length of the optical system, FNO is the aperture number of the optical system, FOV is the maximum field angle of the optical system in the diagonal direction, and TTL is the distance from the object side of the first lens to the imaging plane of the optical system on the optical axis.

[0107] Table 3b gives the high-order coefficients of each aspheric mirror surface that can be used in the third embodiment, wherein each aspheric surface shape can be defined by the formula given in the first embodiment.

[0108] Table 3b

[0109]

[0110]

[0111] Figure 3b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the third embodiment are shown. The reference wavelength of the light of the astigmatism curve and the distortion curve is 555nm. Figure 3b It can be seen that the optical system provided in the third embodiment can achieve good imaging quality.

[0112] Fourth embodiment

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

[0114] The first lens L1 has positive refractive power. The object-side surface S1 of the first lens L1 is convex along the optical axis and concave along the circumference. The image-side surface S2 of the first lens L1 is concave along the optical axis and convex along the circumference.

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

[0116] The third lens L3 has negative refractive power. The object-side surface S5 of the third lens L3 is convex along the optical axis and concave along the circumference. The image-side surface S6 of the third lens L3 is concave along the optical axis and along the circumference.

[0117] The fourth lens L4 has negative refractive power. The object-side surface S7 of the fourth lens L4 is convex both on the optical axis and on the circumference. The image-side surface S8 of the fourth lens L4 is concave on the optical axis and convex on the circumference.

[0118] The fifth lens L5 has negative refractive power. The object-side surface S9 of the fifth lens L5 is concave both on the optical axis and on the circumference. The image-side surface S10 of the fifth lens L5 is concave on the optical axis and convex on the circumference.

[0119] The sixth lens L6 has negative refractive power. The object-side surface S11 of the sixth lens L6 is convex both at the optical axis and at the circumference. The image-side surface S12 of the sixth lens L6 is concave both at the optical axis and at the circumference.

[0120] The other structures of the fourth embodiment are the same as those of the first embodiment, and can be used as a reference.

[0121] Table 4a shows a table of characteristics of the optical system of this embodiment, wherein the data are obtained using light with a wavelength of 587 nm, and the units of Y radius, thickness and focal length are all millimeters (mm).

[0122] Table 4a

[0123]

[0124] Wherein, f is the effective focal length of the optical system, FNO is the aperture number of the optical system, FOV is the maximum field angle of the optical system in the diagonal direction, and TTL is the distance from the object side of the first lens to the imaging plane of the optical system on the optical axis.

[0125] Table 4b gives the high-order coefficients of the aspheric mirror surfaces that can be used in the fourth embodiment, wherein the aspheric surface shapes can be defined by the formula given in the first embodiment.

[0126] Table 4b

[0127]

[0128]

[0129] Figure 4b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the fourth embodiment are shown. The reference wavelength of the light of the astigmatism curve and the distortion curve is 555nm. Figure 4b It can be seen that the optical system provided in the fourth embodiment can achieve good imaging quality.

[0130] Fifth embodiment

[0131] Please refer to Figure 5a and Figure 5b The optical system of this embodiment includes, in order from the object side to the image side along the optical axis:

[0132] The first lens L1 has positive refractive power. The object-side surface S1 of the first lens L1 is convex along the optical axis and concave along the circumference. The image-side surface S2 of the first lens L1 is convex along the optical axis and along the circumference.

[0133] The second lens L2 has negative refractive power. The object-side surface S3 of the second lens L2 is convex both on the optical axis and on the circumference. The image-side surface S4 of the second lens L2 is concave on the optical axis and convex on the circumference.

[0134] The third lens L3 has negative refractive power. The object-side surface S5 of the third lens L3 is convex along the optical axis and concave along the circumference. The image-side surface S6 of the third lens L3 is concave along the optical axis and along the circumference.

[0135] The fourth lens L4 has negative refractive power. The object-side surface S7 of the fourth lens L4 is convex both at the optical axis and at the circumference. The image-side surface S8 of the fourth lens L4 is concave both at the optical axis and at the circumference.

[0136] The fifth lens L5 has negative refractive power. The object-side surface S9 of the fifth lens L5 is convex both on the optical axis and on the circumference. The image-side surface S10 of the fifth lens L5 is concave on the optical axis and convex on the circumference.

[0137] The sixth lens L6 has negative refractive power. The object-side surface S11 of the sixth lens L6 is concave at the optical axis and convex at the circumference. The image-side surface S12 of the sixth lens L6 is convex at the optical axis and concave at the circumference.

[0138] The other structures of the fifth embodiment are the same as those of the first embodiment, and can be referred to for reference.

[0139] Table 5a shows a table of characteristics of the optical system of this embodiment, wherein the data are obtained using light with a wavelength of 587 nm, and the units of Y radius, thickness and focal length are all millimeters (mm).

[0140] Table 5a

[0141]

[0142] Wherein, f is the effective focal length of the optical system, FNO is the aperture number of the optical system, FOV is the maximum field angle of the optical system in the diagonal direction, and TTL is the distance from the object side of the first lens to the imaging plane of the optical system on the optical axis.

[0143] Table 5b gives the high-order coefficients of each aspherical mirror surface that can be used in the fifth embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0144] Table 5b

[0145]

[0146]

[0147] Figure 5b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the fifth embodiment are shown. The reference wavelength of the light of the astigmatism curve and the distortion curve is 555nm. Figure 5b It can be seen that the optical system provided in the fifth embodiment can achieve good imaging quality.

[0148] Sixth embodiment

[0149] Please refer to Figure 6a and Figure 6b The optical system of this embodiment includes, in order from the object side to the image side along the optical axis:

[0150] The first lens L1 has positive refractive power. The object-side surface S1 of the first lens L1 is convex along the optical axis and concave along the circumference. The image-side surface S2 of the first lens L1 is convex along the optical axis and along the circumference.

[0151] The second lens L2 has negative refractive power. The object-side surface S3 of the second lens L2 is concave along the optical axis and convex along the circumference. The image-side surface S4 of the second lens L2 is concave along the optical axis and along the circumference.

[0152] The third lens L3 has negative refractive power. The object-side surface S5 of the third lens L3 is concave both on the optical axis and on the circumference. The image-side surface S6 of the third lens L3 is concave both on the optical axis and on the circumference.

[0153] The fourth lens L4 has negative refractive power. The object-side surface S7 of the fourth lens L4 is convex both at the optical axis and at the circumference. The image-side surface S8 of the fourth lens L4 is concave both at the optical axis and at the circumference.

[0154] The fifth lens element L5 has negative refractive power. The object-side surface S9 of the fifth lens element L5 is concave along the optical axis and convex along the circumference. The image-side surface S10 of the fifth lens element L5 is convex along the optical axis and along the circumference.

[0155] The sixth lens L6 has negative refractive power. The object-side surface S11 of the sixth lens L6 is concave at the optical axis and convex at the circumference. The image-side surface S12 of the sixth lens L6 is concave both at the optical axis and at the circumference.

[0156] The other structures of the sixth embodiment are the same as those of the first embodiment, and can be referred to for reference.

[0157] Table 6a shows a table of characteristics of the optical system of this embodiment, wherein the data are obtained using light with a wavelength of 587 nm, and the units of Y radius, thickness and focal length are all millimeters (mm).

[0158] Table 6a

[0159]

[0160] Wherein, f is the effective focal length of the optical system, FNO is the aperture number of the optical system, FOV is the maximum field angle of the optical system in the diagonal direction, and TTL is the distance from the object side of the first lens to the imaging plane of the optical system on the optical axis.

[0161] Table 6b gives the high-order coefficients of each aspheric mirror surface that can be used in the sixth embodiment, wherein each aspheric surface shape can be defined by the formula given in the first embodiment.

[0162] Table 6b

[0163]

[0164]

[0165] Figure 6b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the sixth embodiment are shown. The reference wavelength of the light of the astigmatism curve and the distortion curve is 555nm. Figure 6b It can be seen that the optical system provided in the sixth embodiment can achieve good imaging quality.

[0166] Seventh embodiment

[0167] Please refer to Figure 7a and Figure 7b The optical system of this embodiment includes, in order from the object side to the image side along the optical axis:

[0168] The first lens L1 has positive refractive power. The object-side surface S1 of the first lens L1 is convex along the optical axis and concave along the circumference. The image-side surface S2 of the first lens L1 is convex along the optical axis and along the circumference.

[0169] The second lens L2 has negative refractive power. The object-side surface S3 of the second lens L2 is convex both on the optical axis and on the circumference. The image-side surface S4 of the second lens L2 is concave both on the optical axis and on the circumference.

[0170] The third lens L3 has negative refractive power. The object-side surface S5 of the third lens L3 is convex along the optical axis and concave along the circumference. The image-side surface S6 of the third lens L3 is concave along the optical axis and along the circumference.

[0171] The fourth lens L4 has negative refractive power. The object-side surface S7 of the fourth lens L4 is concave both on the optical axis and on the circumference. The image-side surface S8 of the fourth lens L4 is concave on the optical axis and convex on the circumference.

[0172] The fifth lens L5 has negative refractive power. The object-side surface S9 of the fifth lens L5 is concave both on the optical axis and on the circumference. The image-side surface S10 of the fifth lens L5 is concave on the optical axis and convex on the circumference.

[0173] The sixth lens L6 has negative refractive power. The object-side surface S11 of the sixth lens L6 is convex both at the optical axis and at the circumference. The image-side surface S12 of the sixth lens L6 is concave both at the optical axis and at the circumference.

[0174] The other structures of the seventh embodiment are the same as those of the first embodiment, and can be used as a reference.

[0175] Table 7a shows a table of characteristics of the optical system of this embodiment, wherein the data are obtained using light with a wavelength of 587 nm, and the units of Y radius, thickness and focal length are all millimeters (mm).

[0176] Table 7a

[0177]

[0178] Wherein, f is the effective focal length of the optical system, FNO is the aperture number of the optical system, FOV is the maximum field angle of the optical system in the diagonal direction, and TTL is the distance from the object side of the first lens to the imaging plane of the optical system on the optical axis.

[0179] Table 7b gives the high-order coefficients of each aspheric mirror surface that can be used in the seventh embodiment, wherein the surface shape of each aspheric surface can be defined by the formula given in the first embodiment.

[0180] Table 7b

[0181]

[0182]

[0183] Figure 7b The longitudinal spherical aberration curve, astigmatism curve and distortion curve of the optical system of the seventh embodiment are shown. The reference wavelength of the light of the astigmatism curve and the distortion curve is 555nm. Figure 7b It can be seen that the optical system provided in the seventh embodiment can achieve good imaging quality.

[0184] Table 8 shows the values ​​of TTL / Imgh, TTL / f, f1 / f2345, FNO, map2 / map1, Imgh / tan(HFOV), TTL / (ct23+ct45), and (r4+r1) / (r4-r1) for the optical systems of the first to seventh embodiments. The unit of Imgh / tan(HFOV) is millimeter (mm).

[0185] Table 8

[0186] TTL / Imgh TTL / f f1 / f2345 FNO First embodiment 1.99 0.92 -1.24 2.20 Second embodiment 2.02 0.93 -1.23 2.17 Third embodiment 2.02 0.93 -1.31 2.17 Fourth embodiment 2.02 0.93 -1.19 2.17 Fifth embodiment 2.02 0.93 -1.16 2.17 Sixth embodiment 2.02 0.93 -1.24 2.25 Seventh embodiment 2.02 0.93 -1.23 2.17 map2 / map1 Imgh / tan(HFOV) TTL / (ct23+ct45) (r4+r1) / (r4-r1) First embodiment 0.89 7.57 4.09 3.12 Second embodiment 0.84 7.56 4.53 2.12 Third embodiment 0.81 7.55 3.69 2.30 Fourth embodiment 0.88 7.55 4.06 2.44 Fifth embodiment 0.92 7.56 4.08 2.30 Sixth embodiment 0.83 7.56 3.30 2.17 Seventh embodiment 0.89 7.56 4.05 2.56

[0187] As can be seen from Table 8, the optical systems in the first to seventh embodiments all satisfy the following conditions: TTL / Imgh<2.4, TTL / f<1.1, -2 <f1 / f2345<-0.5、FNO<2.6、0.6<map2 / map1、Imgh / tan(HFOV)> 6mm, 1.5 <TTL / (ct23+ct45)<6、(r4+r1) / (r4-r1)> 1.

[0188] The above disclosure is only a preferred embodiment of the present invention, and certainly cannot be used to limit the scope of the rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. An optical system, characterized in that: There are six lenses with refractive power, including the following from object side to image side: A first lens having positive refractive power, wherein the object-side surface of the first lens is convex at the optical axis; A second lens element having negative refractive power, wherein the image-side surface of the second lens element is concave at the optical axis; The third lens has a refracting power; The fourth lens has a refracting power; The fifth lens has a refracting power; a sixth lens having a refracting power; The optical system satisfies the conditional formula: -1.24≤f1 / f2345≤-1.16; 2.17≤FNO≤2.25; 1.5 <TTL / (ct23+ct45)≤4.53; 3.12≥(r4+r1) / (r4-r1)>1； 7.55mm≤Imgh / tan(HFOV)≤7.57mm; Wherein, f1 is the effective focal length of the first lens, f2345 is the combined focal length of the second lens, the third lens, the fourth lens and the fifth lens; FNO is the aperture number of the optical system; TTL is the distance from the object side surface of the first lens to the imaging surface of the optical system on the optical axis, ct23 is the distance from the image side surface of the second lens to the object side surface of the third lens on the optical axis, ct45 is the distance from the image side surface of the fourth lens to the object side surface of the fifth lens on the optical axis; r1 is the curvature radius of the object side surface of the first lens at the optical axis, r4 is the curvature radius of the image side surface of the second lens at the optical axis; ImgH is half of the diagonal length of the effective pixel area on the imaging surface of the optical system.

2. The optical system according to claim 1, wherein The object-side surface and the image-side surface of any one of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are both aspherical surfaces.

3. The optical system according to claim 1, wherein The optical system satisfies the conditional formula: 1.99≤TTL / Imgh≤2.02; Wherein, ImgH is half of the diagonal length of the effective pixel area on the imaging surface of the optical system.

4. The optical system according to claim 1, wherein The optical system satisfies the conditional formula: 0.92≤TTL / f≤0.93; Wherein, f is the effective focal length of the optical system.

5. The optical system according to claim 1, wherein The optical system satisfies the conditional formula: 3.30≤TTL / (ct23+ct45)≤4.

53.

6. A lens module, characterized in that: The optical system comprises a lens barrel, a photosensitive element, and the optical system according to any one of claims 1 to 5, wherein the first lens to the sixth lens of the optical system are installed in the lens barrel, and the photosensitive element is arranged on the image side of the optical system.

7. An electronic device, characterized in that: It comprises a shell and the lens module as claimed in claim 6, wherein the lens module is arranged in the shell.

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