Optical systems, camera modules and electronic equipment

Abstract

An optical system, a camera module and an electronic device, wherein the optical system includes, from the object side to the image side along the optical axis, the first lens to the sixth lens with refractive power, wherein the first lens has a negative refractive power, and the third lens has a positive refractive power, wherein the image side surface of the first lens and the object side surface of the second lens are both concave surfaces near the optical axis, and the image side surface of the second lens, the object side surface and the image side surface of the third lens, the image side surface of the fifth lens, and the object side surface of the sixth lens are all convex surfaces near the optical axis. By rationally designing the surface shape and refractive power of each lens of the optical system, it is beneficial to meet the characteristics of a larger field of view angle, a larger aperture, a large image height and lightness and thinness.

Description

Technical Field

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

[0002] In recent years, as camera modules are increasingly used in automotive assisted driving systems, people have put forward higher requirements for the imaging quality and diversity of camera modules, such as a larger field of view, clearer imaging, and sufficient light intake in dim environments. However, the improvement of imaging quality usually means a more complex structure of the optical system, which ultimately leads to an increase in the size and total length of the camera module, making it difficult to apply to thin and light electronic products.

[0003] Therefore, how to optimize the imaging quality and meet the requirements of large aperture, large image height and lightness while ensuring that the optical system has a large field of view has become one of the problems that must be solved in the industry. Summary of the invention

[0004] The purpose of the present invention is to provide an optical system, a camera module and an electronic device to solve the problem in the prior art that the optical system needs to have a large aperture, a large image height and be lightweight while having a large field of view.

[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, comprising a total of six lenses with refractive power, which include, in order from the object side to the image side along the optical axis: a first lens having negative refractive power, wherein the image side surface of the first lens is concave at the near optical axis; a second lens having refractive power, wherein the object side surface of the second lens is concave at the near optical axis, and the image side surface of the second lens is convex at the near optical axis; a third lens having positive refractive power, wherein both the object side surface and the image side surface of the third lens are convex at the near optical axis; a fourth lens having refractive power; a fifth lens having refractive power, wherein the image side surface of the fifth lens is convex at the near optical axis; and a sixth lens having refractive power, wherein the object side surface of the sixth lens is convex at the near optical axis.

[0007] The optical system satisfies the relationship: 150deg<(FOV*f) / Y<158deg; wherein FOV is the maximum field of view of the optical system, f is the focal length of the optical system, and Y is half of the image height corresponding to the maximum field of view of the optical system.

[0008] By making the first lens have a negative refractive power and the image side of the first lens be concave near the optical axis, it is beneficial to increase the incident angle of light, expand the field of view angle of the optical system. At the same time, it is also beneficial to reduce the head aperture of the optical system and increase the screen occupation ratio of the optical system; by making the object side of the second lens be concave near the optical axis and the image side of the second lens be convex near the optical axis, it is beneficial for the light to enter gently, so that the light will not be bent too much, effectively reducing the field curvature and astigmatism of the optical system, and the small-angle deflection of the light is beneficial to achieve the large-aperture effect; by making the third lens have a positive refractive power and both the object side and the image side of the third lens be convex near the optical axis, it is beneficial to contract the light, provide a reasonable incident angle for the marginal light, reduce the marginal aberration and the risk of ghost images. At the same time, it can also shorten the length of the optical system on the optical axis, which is beneficial to realize the thin and light of the optical system; by making the refractive powers of the fourth lens and the fifth lens cooperate with each other, and matching the convex surface of the image side of the fifth lens near the optical axis, it is beneficial to contract the light, correct the aberrations with each other, and reduce the aberrations and chromatic aberrations of the optical system; by making the object side of the sixth lens be convex near the optical axis, it is beneficial to reduce the distortion of the optical system and increase the illuminance. Therefore, satisfying the above configuration of refractive power and surface type is beneficial for the optical system to achieve the effects of a larger field of view angle, a larger aperture and being thin and light.

[0009] By making the optical system satisfy the relational expression 150deg < (FOV * f) / Y < 158deg, it is beneficial to achieve the effect of a large image height while having a large field of view angle, which is thus beneficial for matching with a larger-size photosensitive chip and improving the imaging quality of the optical system. Below the lower limit of the relational expression, the maximum field of view angle of the optical system is too small to reach the required field of view angle of the camera module, which is not conducive to safe driving; exceeding the upper limit of the relational expression, the image height corresponding to the maximum field of view angle of the optical system is too small, making it difficult to match with a large-size photosensitive chip, and easily causing the incident angle of the chief ray to be too large, thereby generating vignetting and reducing the imaging quality, which is not conducive to achieving the effect of a large image height.

[0010] In one implementation, the optical system satisfies the relational expression: 1.6 < f3 / f < 2.0; where f3 is the focal length of the third lens. By making the optical system satisfy the above relational expression, it is beneficial to reasonably configure the ratio of the focal length of the third lens to the focal length of the optical system, correct the marginal aberration, and improve the imaging resolution of the optical system. Exceeding the upper limit of the relational expression, the refractive power of the third lens is too weak, which is not conducive to the correction of chromatic aberration and aberration, thus reducing the imaging quality; below the lower limit of the relational expression, the focal length of the optical system is too large, which is not conducive to increasing the maximum field of view angle of the optical system to achieve the characteristic of a larger field of view angle.

[0011] In one embodiment, the optical system satisfies the relationship: 9.7 mm < |f4 * f5 / f| < 12.5 mm; where f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, and the fourth lens and the fifth lens are cemented together. By making the optical system satisfy the above relationship, it is beneficial to reduce the angle of the light exiting the optical system after being refracted by the lens group, thereby reducing the incident angle of the light entering the photosensitive element on the image side of the optical system, which is beneficial to improving the photosensitive performance of the photosensitive element and thus improving the imaging quality of the imaging system; by cementing the fourth lens and the fifth lens together, it is beneficial to converge the light, correct the aberrations with each other, and reduce the aberrations and chromatic aberrations of the optical system.

[0012] In one embodiment, the optical system satisfies the relationship: 8.5 mm < f * tan(FOV / 2) < 9.7 mm; where FOV / 2 is half of the maximum field of view angle of the optical system, and tan(FOV / 2) is the tangent value of half of the maximum field of view angle of the optical system. By making the optical system satisfy the above relationship, it is beneficial for the optical system to have the characteristics of high pixels, reasonably configure the focal length and the field of view angle, so as to obtain a better wide-angle shooting effect while having appropriate distortion, and meet the requirements of large field of view angle and imaging quality for electronic products such as mobile phones, cameras, vehicles, monitors, and medical devices.

[0013] In one embodiment, the optical system satisfies the relationship: 1 < |f12 / f| < 2.5; where f12 is the combined focal length of the first lens and the second lens. By making the optical system satisfy the above relationship, it is beneficial to reduce the design sensitivity of the optical system, balance the refractive power distribution between the lenses, and improve the imaging quality of the optical system. Below the lower limit of the relationship, the refractive power of the first lens and the second lens is too strong, which is likely to generate strong astigmatism and chromatic aberration, and is not conducive to realizing the high-resolution imaging characteristics of the optical system; exceeding the upper limit of the relationship, the refractive power of the first lens and the second lens is insufficient, and it is difficult for large-angle light to enter the optical system, which is not conducive to expanding the field of view range of the optical system.

[0014] In one embodiment, the optical system satisfies the relationship: 0.5 < SL / TTL < 0.75; where SL is the distance from the aperture of the optical system to the imaging plane on the optical axis, and TTL is the distance from the object side surface of the first lens to the imaging plane on the optical axis, that is, the total length. By making the optical system satisfy the above relationship, it is beneficial to reasonably set the aperture in the optical system, increase the aperture of the aperture, so as to effectively control the incident angle of the marginal field light when entering the optical system, adjust the light input amount of the optical system, improve the relative brightness of the marginal field, and thus improve the imaging quality. Below the lower limit of the relationship, the total length of the optical system is too large, which is not conducive to meeting the requirement of the optical system for being thin and light; exceeding the upper limit of the relationship, the imaging range of the object space of the optical system is too small, which is not conducive to meeting the requirement of the optical system for being wide-angle.

[0015] In one embodiment, the optical system satisfies the relationship: 2<|R10 / R9|<9.5; wherein R10 is the radius of curvature of the image side of the fifth lens at the optical axis, and R9 is the radius of curvature of the object side of the fifth lens at the optical axis. By making the optical system satisfy the above relationship, it is beneficial to reasonably configure the ratio of the radius of curvature of the image side of the fifth lens at the optical axis to the radius of curvature of the object side of the fifth lens at the optical axis, control the shape of the fifth lens, reduce the risk of ghosting, and improve the resolution of the optical system. Below the lower limit of the relationship, the absolute value of the radius of curvature of the image side of the fifth lens at the optical axis is too small, and the curvature of the image side of the fifth lens is too large, which is not conducive to the processing and molding of the fifth lens; exceeding the upper limit of the relationship, the absolute value of the radius of curvature of the image side of the fifth lens at the optical axis is too large, and the image side of the fifth lens is too smooth, which is easy to reflect with other lenses, increasing the risk of ghosting.

[0016] In one embodiment, the optical system satisfies the relationship: 0.7<(R1+R2) / (R1-R2)<2.7; wherein R1 is the radius of curvature of the object side of the first lens at the optical axis, and R2 is the radius of curvature of the image side of the first lens at the optical axis. By making the optical system satisfy the above relationship, it is beneficial to reasonably control the radius of curvature of the object side and the image side of the first lens, thereby effectively controlling the shape of the first lens, so that the first lens refracts the incident light more gently and avoids increasing the aberration. Below the lower limit of the relationship, the difference in radius of curvature between the object side and the image side of the first lens at the optical axis is too large, the object side or the image side of the first lens is too flat, and the refraction effect of the first lens on the incident light is weakened, which is not conducive to controlling the total length of the optical system; exceeding the upper limit of the relationship, the difference in radius of curvature between the object side and the image side of the first lens at the optical axis is too small, the curvature of the light by the first lens is too large, and it is easy to reflect with other lenses to produce ghost images.

[0017] In the second aspect, the present invention further provides a camera module, which includes a photosensitive chip and an optical system described in any one of the embodiments of the first aspect, wherein the photosensitive chip is arranged on the image side of the optical system. Wherein, the photosensitive surface of the photosensitive chip is located on the imaging surface of the optical system, and the light of the object incident on the photosensitive surface through the lens can be converted into an electrical signal of the image. The photosensitive chip can be a complementary metal oxide semiconductor (CMOS) or a charge-coupled device (CCD). The camera module can be an imaging module integrated in an electronic device, or it can be an independent lens. By adding the optical system provided by the present invention to the camera module, the surface shape and refractive power of each lens in the optical system can be reasonably designed, so that the camera module has the characteristics of a larger field of view angle, a larger aperture, a large image height and lightness.

[0018] In a third aspect, the present invention further provides an electronic device, the electronic device comprising a housing and the camera module described in the second aspect, the camera module being disposed in the housing. The electronic device includes but is not limited to a smart phone, a computer, and a smart watch. By adding the camera module provided by the present invention to the electronic device, the electronic device has the characteristics of a larger field of view, a larger aperture, a larger image height, and a thin and light structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

[0020] Figure 1 is a schematic structural diagram of the optical system of the first embodiment;

[0021] Figure 2 shows a longitudinal spherical aberration curve diagram, an astigmatism curve diagram and a distortion curve diagram of the first embodiment;

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

[0023] Figure 4 shows a longitudinal spherical aberration curve diagram, an astigmatism curve diagram and a distortion curve diagram of the second embodiment;

[0024] Figure 5 is a schematic structural diagram of an optical system of a third embodiment;

[0025] Figure 6shows a longitudinal spherical aberration curve diagram, an astigmatism curve diagram and a distortion curve diagram of the third embodiment;

[0026] Figure 7 is a schematic structural diagram of an optical system of a fourth embodiment;

[0027] Figure 8 shows a longitudinal spherical aberration curve diagram, an astigmatism curve diagram and a distortion curve diagram of the fourth embodiment;

[0028] Fig. 9 is a schematic structural diagram of an optical system of a fifth embodiment;

[0029] Fig.10 shows a longitudinal spherical aberration curve diagram, an astigmatism curve diagram and a distortion curve diagram of the fifth embodiment;

[0030] Fig.11 A schematic structural diagram of a camera module in one embodiment of the present invention is shown;

[0031] Fig.12 A schematic structural diagram of an electronic device in an embodiment of the present invention is shown. DETAILED DESCRIPTION

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

[0033] In a first aspect, the present invention provides an optical system, comprising a total of six lenses with refractive power, which include, in order from the object side to the image side along the optical axis: a first lens having negative refractive power, the object side surface of the first lens at the near optical axis can be convex, concave or flat, and the image side surface of the first lens at the near optical axis is concave; a second lens having positive refractive power or negative refractive power, the object side surface of the second lens at the near optical axis is concave, and the image side surface of the second lens at the near optical axis is convex; a third lens having positive refractive power, the object side surface and the image side surface of the third lens at the near optical axis are concave, and the image side surface of the second lens at the near optical axis is convex; The fourth lens may have positive or negative refractive power, and the object side surface and the image side surface of the fourth lens may be convex, concave or flat at the near optical axis; the fifth lens may have positive or negative refractive power, and the object side surface of the fifth lens may be convex, concave or flat at the near optical axis, and the image side surface of the fifth lens is convex at the near optical axis; the sixth lens may have positive or negative refractive power, and the object side surface of the sixth lens may be convex at the near optical axis, and the image side surface of the sixth lens may be convex, concave or flat at the near optical axis.

[0034] The optical system satisfies the relationship: 150deg<(FOV*f) / Y<158deg; wherein FOV is the maximum field of view of the optical system, f is the focal length of the optical system, and Y is half of the image height corresponding to the maximum field of view of the optical system.

[0035] By making the first lens have negative refractive power and the image side surface of the first lens is concave at the near optical axis, it is beneficial to increase the incident angle of light and expand the field angle of the optical system. At the same time, it is also beneficial to reduce the head diameter of the optical system and increase the screen-to-body ratio of the optical system; by making the object side surface of the second lens be concave at the near optical axis and the image side surface of the second lens be convex at the near optical axis, it is beneficial to the smooth injection of light so that the light will not be bent too much, effectively reducing the field curvature and astigmatism of the optical system, and the small angle deflection of light is beneficial to achieve a large aperture effect; by making the third lens have positive refractive power and the third lens have positive refractive power, The object side and image side of the three lenses are convex at the near optical axis, which is conducive to shrinking the light, providing a reasonable incident angle for the edge light, reducing edge aberrations and reducing the risk of ghost images. At the same time, it can also shorten the length of the optical system on the optical axis, which is conducive to achieving a thinner and lighter optical system. By matching the refractive power of the fourth lens and the fifth lens, and matching the convex surface of the image side of the fifth lens at the near optical axis, it is conducive to shrinking the light, correcting the aberrations, and reducing the aberration and chromatic aberration of the optical system. By making the object side of the sixth lens convex at the near optical axis, it is conducive to reducing the distortion of the optical system and increasing the illumination. Therefore, the configuration of the above refractive power and surface shape is conducive to the optical system to achieve a larger field angle, a larger aperture and a thinner effect.

[0036] By making the optical system satisfy the relationship 150deg<(FOV*f) / Y<158deg, it is beneficial to have a large field of view and achieve a large image height, which is beneficial to match with a larger photosensitive chip and improve the imaging quality of the optical system. Below the lower limit of the relationship, the maximum field of view of the optical system is too small, which cannot meet the field of view required by the camera module, which is not conducive to safe driving; exceeding the upper limit of the relationship, the image height corresponding to the maximum field of view of the optical system is too small, which is difficult to match with a large photosensitive chip, and it is easy to cause the main light incident angle to be too large, which will cause dark angles, reduce imaging quality, and is not conducive to achieving a large image height effect.

[0037] In one embodiment, the optical system satisfies the relation: 1.6 < f3 / f < 2.0; where f3 is the focal length of the third lens. By making the optical system satisfy the above relation, it is beneficial to reasonably configure the ratio of the focal length of the third lens to the focal length of the optical system, correct the marginal aberration, and improve the imaging resolution of the optical system. Exceeding the upper limit of the relation, the refractive power of the third lens is too weak, which is not conducive to correcting chromatic aberration and aberration, thereby reducing the imaging quality; below the lower limit of the relation, the focal length of the optical system is too large, which is not conducive to increasing the maximum field of view angle of the optical system to achieve the characteristics of a large field of view angle.

[0038] In one embodiment, the optical system satisfies the relation: 9.7 mm < |f4*f5 / f| < 12.5 mm; where f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, and the fourth lens and the fifth lens are cemented. By making the optical system satisfy the above relation, it is beneficial to reduce the angle of the light exiting the optical system after being refracted by the lens group, and further reduce the incident angle of the light entering the image-side photosensitive element of the optical system, which is beneficial to improving the photosensitive performance of the photosensitive element, and further improving the high-quality imaging of the imaging system; by cementing the fourth lens and the fifth lens, it is beneficial to contract the light, correct the aberration with each other, and reduce the aberration and chromatic aberration of the optical system.

[0039] In one embodiment, the optical system satisfies the relation: 8.5 mm < f*tan(FOV / 2) < 9.7 mm; where FOV / 2 is half of the maximum field of view angle of the optical system, and tan(FOV / 2) is the tangent value of half of the maximum field of view angle of the optical system. By making the optical system satisfy the above relation, it is beneficial to endow the optical system with the characteristics of high pixels, reasonably configure the focal length and the field of view angle, obtain a better wide-angle shooting effect while having appropriate distortion, and meet the requirements of large field of view angle and imaging quality of electronic products such as mobile phones, cameras, vehicles, monitors, and medical devices.

[0040] In one embodiment, the optical system satisfies the relation: 1 < |f12 / f| < 2.5; where f12 is the combined focal length of the first lens and the second lens. By making the optical system satisfy the above relation, it is beneficial to reduce the design sensitivity of the optical system, balance the distribution of refractive power between the lenses, and improve the imaging quality of the optical system. Below the lower limit of the relation, the refractive power of the first lens and the second lens is too strong, which is likely to generate strong astigmatism and chromatic aberration, and is not conducive to realizing the characteristics of high-resolution imaging of the optical system; exceeding the upper limit of the relation, the refractive power of the first lens and the second lens is insufficient, and it is difficult for large-angle light to enter the optical system, which is not conducive to expanding the field of view range of the optical system.

[0041] In one embodiment, the optical system satisfies the relation: 0.5 < SL / TTL < 0.75; where SL is the distance from the aperture of the optical system to the imaging surface on the optical axis, and TTL is the distance from the object side surface of the first lens to the imaging surface on the optical axis, i.e., the total length. By making the optical system satisfy the above relation, it is beneficial to reasonably arrange the aperture in the optical system, increase the aperture diameter of the aperture, so as to effectively control the incident angle of the marginal field light when entering the optical system, adjust the light input amount of the optical system, improve the relative brightness of the marginal field, and thus improve the imaging quality. Below the lower limit of the relation, the total length of the optical system is too large, which is not conducive to meeting the requirement of the optical system for being thin and light; exceeding the upper limit of the relation, the imaging range of the object space of the optical system is too small, which is not conducive to meeting the requirement of the optical system for being wide-angle.

[0042] In one embodiment, the optical system satisfies the relation: 2 < |R10 / R9| < 9.5; where R10 is the curvature radius of the image side surface of the fifth lens at the optical axis, and R9 is the curvature radius of the object side surface of the fifth lens at the optical axis. By making the optical system satisfy the above relation, it is beneficial to reasonably configure the ratio of the curvature radius of the image side surface of the fifth lens at the optical axis to the curvature radius of the object side surface of the fifth lens at the optical axis, control the shape of the fifth lens, and reduce the risk of ghosting, and improve the resolution ability of the optical system. Below the lower limit of the relation, the absolute value of the curvature radius of the image side surface of the fifth lens at the optical axis is too small, and the bending degree of the image side surface of the fifth lens is too large, which is not conducive to the processing and forming of the fifth lens; exceeding the upper limit of the relation, the absolute value of the curvature radius of the image side surface of the fifth lens at the optical axis is too large, and the image side surface of the fifth lens is too smooth, which is easy to reflect with other lenses, increasing the risk of ghosting.

[0043] In one embodiment, the optical system satisfies the relation: 0.7 < (R1 + R2) / (R1 - R2) < 2.7; where R1 is the curvature radius of the object side surface of the first lens at the optical axis, and R2 is the curvature radius of the image side surface of the first lens at the optical axis. By making the optical system satisfy the above relation, it is beneficial to reasonably control the curvature radii of the object side surface and the image side surface of the first lens, and thus effectively control the shape of the first lens, make the first lens refract the incident light more gently, and avoid increasing the aberration. Below the lower limit of the relation, the difference between the curvature radii of the object side surface and the image side surface of the first lens at the optical axis is too large, the object side surface or the image side surface of the first lens is too flat, and the refraction effect of the first lens on the incident light is weakened, which is not conducive to controlling the total length of the optical system; exceeding the upper limit of the relation, the difference between the curvature radii of the object side surface and the image side surface of the first lens at the optical axis is too small, the bending degree of the first lens on the light is too large, and it is easy to reflect with other lenses to generate ghosting.

[0044] In some embodiments, the optical system further includes a filter, which may be an infrared cutoff filter or an infrared bandpass filter. The infrared cutoff filter is used to filter out infrared light, and the infrared bandpass filter only allows infrared light to pass through. In the present application, the filter is an infrared cutoff filter, which is fixedly arranged relative to each lens in the optical system to prevent infrared light from reaching the imaging surface of the optical system and interfering with normal imaging. The filter can be assembled together with each lens as a part of the optical system. In other embodiments, the filter can also be an independent element outside the optical system. The filter can be installed between the optical system and the photosensitive chip when the optical system and the photosensitive chip are assembled. It can be understood that the filter can be made of optical glass coating, or it can be made of colored glass, or a filter of other materials, which can be selected according to actual needs and is not specifically limited in this embodiment. In other embodiments, a filter coating can be set on at least one lens from the first lens to the sixth lens to achieve the effect of filtering out infrared light.

[0045] In some embodiments, the optical system further includes protective glass for covering the photosensitive chip to protect the photosensitive chip.

[0046] The optical system of the present invention is described below by using more specific embodiments:

[0047] First embodiment

[0048] Please refer to Figure 1 and Figure 2 The optical system 10 of this embodiment includes, in order from the object side to the image side along the optical axis direction:

[0049] The first lens L1 has negative refractive power. The object-side surface S1 of the first lens L1 is concave at the near optical axis, and the image-side surface S2 of the first lens L1 is concave at the near optical axis.

[0050] The second lens L2 has positive refractive power. The object-side surface S3 of the second lens L2 is concave at the near optical axis, and the image-side surface S4 is convex at the near optical axis.

[0051] The third lens L3 has positive refractive power. The object-side surface S5 of the third lens L3 is convex at the near optical axis, and the image-side surface S6 is convex at the near optical axis.

[0052] The fourth lens L4 has negative refractive power. The object-side surface S7 of the fourth lens L4 is concave at the near optical axis, and the image-side surface S8 is concave at the near optical axis.

[0053] The fifth lens element L5 has positive refractive power. The object-side surface S9 of the fifth lens element L5 is convex at the near optical axis, and the image-side surface S10 is convex at the near optical axis.

[0054] The sixth lens L6 has negative refractive power. The object-side surface S11 of the sixth lens L6 is convex at the near optical axis, and the image-side surface S12 is concave at the near optical axis.

[0055] In addition, the optical system 10 also includes an aperture STO, a filter IR, a protective glass CG and an imaging surface IMG. In this embodiment, the aperture STO is arranged between the image side surface of the second lens of the optical system 10 and the object side surface of the third lens, and is used to control the amount of light entering. The filter IR is arranged between the sixth lens L6 and the protective glass CG, and includes an object side surface S13 and an image side surface S14. The filter IR includes an infrared cutoff filter IR, which is used to filter out infrared light so that the light incident on the imaging surface IMG is only visible light, and the wavelength of visible light is 380nm-780nm. The material of the first lens L1 to the sixth lens L6 is glass. The effective pixel area of ​​the photosensitive chip is located on the imaging surface IMG.

[0056] Table 1a shows various parameters of the optical system 10 of the present embodiment, wherein the Y radius is the radius of curvature of the object side or image side of the corresponding surface number at the optical axis. Surface number S1 and surface number S2 are the object side S1 and image side S2 of the first lens L1, respectively, that is, in the same lens, the surface with a smaller surface number is the object side, and the surface with a larger surface number is the image side. The first value in the "thickness" parameter column of the first lens L1 is the thickness of the lens on the optical axis, and the second value is the distance from the image side to the next surface of the lens in the image side direction on the optical axis. The reference wavelength of the focal length of the lens is 555nm, and the reference wavelength of the material refractive index and Abbe number of the lens is 587.56nm. The units of the Y radius, thickness and focal length are all millimeters (mm).

[0057] Table 1a

[0058]

[0059]

[0060] Wherein, f is the focal length of the optical system 10 , FNO is the aperture number of the optical system 10 , and FOV is the maximum field angle of the optical system 10 .

[0061] In this embodiment, the object-side surface and the image-side surface of the second lens L2, the third lens L3 and the sixth lens L6 are all aspherical surfaces, and the surface shape x of the aspherical surface can be defined by but not limited to the following aspherical surface formula:

[0062]

[0063] Wherein, x is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, h is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the vertex of the aspherical surface, k is the cone coefficient, and Ai is the coefficient corresponding to the i-th high-order term in the aspherical surface shape formula. Table 1b shows the cone coefficient k and high-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 of the aspherical mirror surfaces S3, S4, S5, S6, S11 and S12 that can be used in the first embodiment.

[0064] Table 1b

[0065]

[0066] Figure 2 (a) shows the longitudinal spherical aberration curves of the optical system 10 of the first embodiment at wavelengths of 642.7300nm, 610.0000nm, 555.0000nm, 510.0000nm, and 420.0000nm, wherein the abscissa along the X-axis direction represents the focus offset, i.e., the distance from the imaging plane to the intersection of the light and the optical axis (in mm), and the ordinate along the Y-axis direction represents the normalized field of view. The longitudinal spherical aberration curve represents the deviation of the convergent focus of light of different wavelengths after passing through each lens of the optical system 10. Figure 2 As can be seen in (a), the degree of deviation of the convergence focus of the light of each wavelength in the first embodiment tends to be consistent, and the dispersion spots or color halos in the imaging picture are effectively suppressed by the optical system 10, indicating that the imaging quality of the optical system 10 in this embodiment is good.

[0067] Figure 2 (b) also shows the astigmatism curve of the optical system 10 of the first embodiment at a wavelength of 555.0000nm, wherein the horizontal axis along the X-axis direction represents the focus offset, and the vertical axis along the Y-axis direction represents the field angle, and its unit is deg. The S curve in the astigmatism curve represents the sagittal field curvature at 555.0000nm, and the T curve represents the meridian field curvature at 555.0000nm. Figure 2 As can be seen in (b), the field curvature of the optical system 10 is small, the field curvature and astigmatism of each field of view are well corrected, and the center and edge of the field of view have clear images.

[0068] Figure 2 (c) also shows the distortion curve of the optical system 10 of the first embodiment when the wavelength is 555.0000nm. The horizontal axis along the X-axis direction represents the distortion value, the unit is %, and the vertical axis along the Y-axis direction represents the field of view angle, the unit is deg. The distortion curve represents the distortion value corresponding to different field of view angles. Figure 2It can be seen from (c) that at a wavelength of 555.0000nm, the image deformation caused by the main beam is small and the imaging quality of the system is excellent.

[0069] Depend on Figure 2 As can be seen from (a), (b) and (c), the optical system 10 of this embodiment has small aberration, good imaging quality and excellent imaging quality.

[0070] Second embodiment

[0071] Please refer to Figure 3 and Figure 4 The optical system 10 of this embodiment includes, in order from the object side to the image side along the optical axis direction:

[0072] The first lens L1 has negative refractive power. The object-side surface S1 of the first lens L1 is concave at the near optical axis, and the image-side surface S2 of the first lens L1 is concave at the near optical axis.

[0073] The second lens L2 has negative refractive power. The object-side surface S3 of the second lens L2 is concave at the near optical axis, and the image-side surface S4 is convex at the near optical axis.

[0074] The third lens L3 has positive refractive power. The object-side surface S5 of the third lens L3 is convex at the near optical axis, and the image-side surface S6 is convex at the near optical axis.

[0075] The fourth lens L4 has negative refractive power. The object-side surface S7 of the fourth lens L4 is convex at the near optical axis, and the image-side surface S8 is concave at the near optical axis.

[0076] The fifth lens element L5 has positive refractive power. The object-side surface S9 of the fifth lens element L5 is convex at the near optical axis, and the image-side surface S10 is convex at the near optical axis.

[0077] The sixth lens L6 has negative refractive power. The object-side surface S11 of the sixth lens L6 is convex at the near optical axis, and the image-side surface S12 is concave at the near optical axis.

[0078] The other structures of the second embodiment are the same as those of the first embodiment, and can be used as a reference.

[0079] Table 2a shows various parameters of the optical system 10 of this embodiment, wherein the aperture STO is arranged between the image side surface of the third lens and the object side surface of the fourth lens of the optical system 10, the filter IR is arranged between the sixth lens L6 and the protective glass CG, the reference wavelength of the focal length of the lens is 555nm, the reference wavelength of the material refractive index and the Abbe number of the lens is 587.56nm, the units of the Y radius, thickness and focal length are all millimeters (mm), and the meanings of other parameters are the same as those of the first embodiment.

[0080] Table 2a

[0081]

[0082]

[0083] Table 2b gives the coefficients of the higher-order terms that can be used for each aspherical mirror surface in the second embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0084] Table 2b

[0085]

[0086] Figure 4 (a) shows the longitudinal spherical aberration curves of the optical system 10 of the second embodiment at wavelengths of 642.7300nm, 610.0000nm, 555.0000nm, 510.0000nm, and 420.0000nm, wherein the abscissa along the X-axis direction represents the focus offset, i.e., the distance from the imaging plane to the intersection of the light and the optical axis (in mm), and the ordinate along the Y-axis direction represents the normalized field of view. The longitudinal spherical aberration curve represents the deviation of the convergent focus of light of different wavelengths after passing through each lens of the optical system 10. Figure 4 As can be seen in (a), the degree of deviation of the convergence focus of the light of each wavelength in the first embodiment tends to be consistent, and the dispersion spots or color halos in the imaging picture are effectively suppressed by the optical system 10, indicating that the imaging quality of the optical system 10 in this embodiment is good.

[0087] Figure 4 (b) also shows the astigmatism curve of the optical system 10 of the second embodiment at a wavelength of 555.0000nm, wherein the horizontal axis along the X-axis direction represents the focus offset, and the vertical axis along the Y-axis direction represents the image height, and the unit is mm. The S curve in the astigmatism curve represents the sagittal field curvature at 555.0000nm, and the T curve represents the meridian field curvature at 555.0000nm. Figure 4 As can be seen in (b), the field curvature of the optical system 10 is small, the field curvature and astigmatism of each field of view are well corrected, and the center and edge of the field of view have clear images.

[0088] Figure 4 (c) also shows the distortion curve of the optical system 10 of the second embodiment when the wavelength is 555.0000nm. The horizontal axis along the X-axis direction represents the distortion value, the unit is %, and the vertical axis along the Y-axis direction represents the field of view angle, the unit is deg. The distortion curve represents the distortion value corresponding to different field of view angles. Figure 4 It can be seen from (c) that at a wavelength of 555.0000nm, the image deformation caused by the main beam is small and the imaging quality of the system is excellent.

[0089] Depend on Figure 4 As can be seen from (a), (b) and (c), the optical system 10 of this embodiment has small aberration, good imaging quality and excellent imaging quality.

[0090] Third embodiment

[0091] Please refer to Figure 5 and Figure 6 The optical system 10 of this embodiment includes, in order from the object side to the image side along the optical axis direction:

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

[0093] The second lens L2 has negative refractive power. The object-side surface S3 of the second lens L2 is concave at the near optical axis, and the image-side surface S4 is convex at the near optical axis.

[0094] The third lens L3 has positive refractive power. The object-side surface S5 of the third lens L3 is convex at the near optical axis, and the image-side surface S6 is convex at the near optical axis.

[0095] The fourth lens L4 has positive refractive power. The object-side surface S7 of the fourth lens L4 is convex at the near optical axis, and the image-side surface S8 is convex at the near optical axis.

[0096] The fifth lens element L5 has negative refractive power. The object-side surface S9 of the fifth lens element L5 is concave at the near optical axis, and the image-side surface S10 is convex at the near optical axis.

[0097] The sixth lens L6 has positive refractive power. The object-side surface S11 of the sixth lens L6 is convex at the near optical axis, and the image-side surface S12 is concave at the near optical axis.

[0098] The other structures of the third embodiment are the same as those of the first embodiment, and can be used as a reference.

[0099] Table 3a shows various parameters of the optical system 10 of this embodiment, wherein the filter IR is arranged between the sixth lens L6 and the imaging plane IMG, the reference wavelength of the focal length of the lens is 555 nm, the reference wavelength of the material refractive index and the Abbe number of the lens is 587.56 nm, the units of the Y radius, thickness and focal length are all millimeters (mm), and the meanings of other parameters are the same as those of the first embodiment.

[0100] Table 3a

[0101]

[0102]

[0103] Table 3b gives the coefficients of the higher-order terms that can be used for each aspherical mirror surface in the third embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0104] Table 3b

[0105]

[0106] See also Figure 6 ,Depend on Figure 6 It can be seen from the longitudinal spherical aberration diagram (a), astigmatism curve diagram (b) and distortion curve diagram (c) in the figure that the longitudinal spherical aberration, astigmatism and distortion of the optical system 10 are well controlled, so that the optical system 10 of this embodiment has good imaging quality. Figure 6 (a) Figure 6 (b) and Figure 6 The wavelengths corresponding to the curves in (c) can be referred to in the second embodiment. Figure 4 (a) Figure 4 (b) Figure 4 The contents described in (c) will not be repeated here.

[0107] Fourth embodiment

[0108] Please refer to Figure 7 and Figure 8 The optical system 10 of this embodiment includes, in order from the object side to the image side along the optical axis direction:

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

[0110] The second lens L2 has negative refractive power. The object-side surface S3 of the second lens L2 is concave at the near optical axis, and the image-side surface S4 is convex at the near optical axis.

[0111] The third lens L3 has positive refractive power. The object-side surface S5 of the third lens L3 is convex at the near optical axis, and the image-side surface S6 is convex at the near optical axis.

[0112] The fourth lens L4 has positive refractive power. The object-side surface S7 of the fourth lens L4 is convex at the near optical axis, and the image-side surface S8 is convex at the near optical axis.

[0113] The fifth lens element L5 has negative refractive power. The object-side surface S9 of the fifth lens element L5 is concave at the near optical axis, and the image-side surface S10 is convex at the near optical axis.

[0114] The sixth lens L6 has positive refractive power. The object-side surface S11 of the sixth lens L6 is convex at the near optical axis, and the image-side surface S12 is convex at the near optical axis.

[0115] The other structures of the fourth embodiment are the same as those of the first embodiment, and can be referred to herein.

[0116] Table 4a shows various parameters of the optical system 10 of this embodiment, wherein the filter IR is arranged between the sixth lens L6 and the imaging plane IMG, the reference wavelength of the focal length of the lens is 555 nm, the reference wavelength of the material refractive index and the Abbe number of the lens is 587.56 nm, the units of the Y radius, thickness and focal length are all millimeters (mm), and the meanings of other parameters are the same as those of the first embodiment.

[0117] Table 4a

[0118]

[0119] Table 4b gives the coefficients of the higher-order terms that can be used for each aspherical mirror surface in the fourth embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0120] Table 4b

[0121]

[0122] See also Figure 8 ,Depend on Figure 8 It can be seen from the longitudinal spherical aberration diagram (a), astigmatism curve diagram (b) and distortion curve diagram (c) in the figure that the longitudinal spherical aberration, astigmatism and distortion of the optical system 10 are well controlled, so that the optical system 10 of this embodiment has good imaging quality. Figure 8 (a) Figure 8 (b) and Figure 8 The wavelengths corresponding to the curves in (c) can be referred to in the second embodiment. Figure 4 (a) Figure 4 (b) Figure 4 The contents described in (c) will not be repeated here.

[0123] Fifth embodiment

[0124] Please refer to Fig. 9 and Fig.10 The optical system 10 of this embodiment includes, in order from the object side to the image side along the optical axis direction:

[0125] The first lens L1 has negative refractive power. The object-side surface S1 of the first lens L1 is convex at the near optical axis, and the image-side surface S2 is concave at the near optical axis.

[0126] The second lens L2 has negative refractive power. The object-side surface S3 of the second lens L2 is concave at the near optical axis, and the image-side surface S4 is convex at the near optical axis.

[0127] The third lens L3 has positive refractive power. The object-side surface S5 of the third lens L3 is convex at the near optical axis, and the image-side surface S6 is convex at the near optical axis.

[0128] The fourth lens L4 has positive refractive power. The object-side surface S7 of the fourth lens L4 is convex at the near optical axis, and the image-side surface S8 is convex at the near optical axis.

[0129] The fifth lens element L5 has negative refractive power. The object-side surface S9 of the fifth lens element L5 is concave at the near optical axis, and the image-side surface S10 is convex at the near optical axis.

[0130] The sixth lens L6 has positive refractive power. The object-side surface S11 of the sixth lens L6 is convex at the near optical axis, and the image-side surface S12 is concave at the near optical axis.

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

[0132] Table 5a shows various parameters of the optical system 10 of this embodiment, wherein the filter IR and the protective glass CG are arranged between the sixth lens L6 and the imaging surface IMG, the reference wavelength of the focal length of the lens is 555 nm, the reference wavelength of the material refractive index and the Abbe number of the lens is 587.56 nm, the units of the Y radius, thickness and focal length are all millimeters (mm), and the meanings of other parameters are the same as those of the first embodiment.

[0133] Table 5a

[0134]

[0135] Table 5b gives the coefficients of the higher-order terms that can be used for each aspherical mirror surface in the fifth embodiment, wherein each aspherical surface shape can be defined by the formula given in the first embodiment.

[0136] Table 5b

[0137]

[0138] See also Fig.10 ,Depend on Fig.10 It can be seen from the longitudinal spherical aberration diagram (a), astigmatism curve diagram (b) and distortion curve diagram (c) in the figure that the longitudinal spherical aberration, astigmatism and distortion of the optical system 10 are well controlled, so that the optical system 10 of this embodiment has good imaging quality. Fig.10 (a) Fig.10 (b) and Fig.10 The wavelengths corresponding to the curves in (c) can be referred to in the second embodiment. Figure 4 (a) Figure 4 (b) Figure 4The content described in (c) thereof will not be elaborated here.

[0139] Table 6 shows the values of (FOV*f) / Y, f3 / f, |f4*f5 / f|, f*tan(FOV / 2), |f12 / f|, SL / TTL, |R10 / R9|, and (R1+R2) / (R1-R2) in the optical systems of the first to fifth embodiments.

[0140] Table 6

[0141] First embodiment Second embodiment Third embodiment Fourth embodiment Fifth embodiment (FOV*f) / Y(deg) 156.8 156.8 150.1 155.5 157.2 f3 / f 1.62 1.92 1.78 1.74 1.74 |f4*f5 / f|(mm) 10.53 10.89 12.09 9.96 10.91 f*tan(FOV / 2)(mm) 9.59 9.59 8.54 9.27 9.61 |f12 / f| 2.41 1.95 1.09 1.12 1.04 SL / TTL 0.74 0.51 0.69 0.70 0.71 |R10 / R9| 2.08 2.20 5.31 6.10 9.40 (R1+R2) / (R1-R2) 0.84 0.74 2.62 2.25 2.45

[0142] As can be seen from Table 6, the optical systems of the first to fifth embodiments all satisfy the following relational expressions: 150deg < (FOV*f) / Y < 158deg, 1.6 < f3 / f < 2.0, 9.7mm < |f4*f5 / f| < 12.5mm, 8.5mm < f*tan(FOV / 2) < 9.7mm, 1 < |f12 / f| < 2.5, 0.5 < SL / TTL < 0.75, 2 < |R10 / R9| < 9.5, and 0.7 < (R1+R2) / (R1-R2) < 2.7.

[0143] Please refer to Fig.11 , the present invention also provides an imaging module 20, which includes an image sensor chip 21 and the optical system 10 according to any one of the embodiments of the first aspect. The image sensor chip 21 is disposed on the image side of the optical system 10. Among them, the photosensitive surface of the image sensor chip 21 is located on the imaging surface of the optical system 10, and the light of the object incident on the photosensitive surface through the lens can be converted into an electrical signal of an image. The image sensor chip 21 can be a Complementary Metal Oxide Semiconductor (CMOS) or a Charge-coupled Device (CCD). By adding the optical system 10 provided by the present invention to the imaging module 20, the imaging module 20 can be reasonably designed in terms of the surface shape and refractive power of each lens in the optical system 10, so that the imaging module 20 has the characteristics of a large field of view angle, a large aperture, a large image height, and being thin and light.

[0144] Please refer to Fig.12 , the present invention also provides an electronic device 30, which includes a housing 31 and the above-mentioned imaging module 20, and the imaging module 20 is disposed in the housing 31. The electronic device 30 includes but is not limited to a smart phone, a computer, a smart watch, etc. By adding the imaging module 20 provided by the present invention to the electronic device 30, the electronic device 30 has the characteristics of a large field of view angle, a large aperture, a large image height, and being thin and light.

[0145] The above disclosures are only some preferred embodiments of the present invention, which certainly cannot be used to limit the scope of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. An optical system, characterized in that: There are six refractive lenses, including: A first lens has negative refractive power, and the image side surface of the first lens is concave at the near optical axis; A second lens having refractive power, wherein the object side surface of the second lens is concave at the near optical axis, and the image side surface of the second lens is convex at the near optical axis; A third lens element has positive refractive power, and both the object side surface and the image side surface of the third lens element are convex surfaces at the near optical axis; The fourth lens has refractive power; a fifth lens element having refractive power, wherein the image side surface of the fifth lens element is a convex surface near the optical axis; a sixth lens having refractive power, wherein the object side surface of the sixth lens is a convex surface near the optical axis; The optical system satisfies the relationship: 150deg<(FOV*f) / Y<158deg, 8.5mm <f*tan(FOV / 2)<9.7mm; Among them, FOV is the maximum field of view of the optical system, f is the focal length of the optical system, Y is half of the image height corresponding to the maximum field of view of the optical system, and tan(FOV / 2) is the tangent value of half of the maximum field of view of the optical system.

2. The optical system according to claim 1, wherein: The optical system satisfies the relationship: 1.6 <f3 / f<2.0; Wherein, f3 is the focal length of the third lens.

3. The optical system according to claim 1, wherein: The optical system satisfies the relationship: 9.7mm<|f4*f5 / f|<12.5mm; Among them, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, and the fourth lens is glued to the fifth lens.

4. The optical system according to claim 1, wherein: The optical system satisfies the relationship: 1<|f12 / f|<2.5; Wherein, f12 is the combined focal length of the first lens and the second lens.

5. The optical system according to claim 1, wherein: The optical system satisfies the relationship: 0.5 <SL / TTL<0.75; Wherein, SL is the distance from the aperture of the optical system to the imaging plane on the optical axis, and TTL is the distance from the object side of the first lens to the imaging plane on the optical axis.

6. The optical system according to claim 1, wherein: The optical system satisfies the relationship: 2<|R10 / R9|<9.5; Wherein, R10 is the curvature radius of the image side surface of the fifth lens at the optical axis, and R9 is the curvature radius of the object side surface of the fifth lens at the optical axis.

7. The optical system according to claim 1, wherein: The optical system satisfies the relationship: 0.7<(R1+R2) / (R1-R2)<2.7; Wherein, R1 is the curvature radius of the object side surface of the first lens at the optical axis, and R2 is the curvature radius of the image side surface of the first lens at the optical axis.

8. A camera module, characterized in that: It comprises the optical system as claimed in any one of claims 1 to 7 and a photosensitive chip, wherein the photosensitive chip is located on the image side of the optical system.

9. An electronic device, characterized in that: The electronic device includes a housing and a camera module as described in claim 8, and the camera module is arranged in the housing.

Images