Optical system, imaging device and terminal equipment

Abstract

The embodiment of the present application provides an optical system, an imaging device and a terminal device. The optical system includes an object plane, an image plane, an aperture, a filter and seven lenses. By setting a non-rotationally symmetrical aspherical surface on at least one of the seven lenses, an ultra-wide-angle and small-distortion imaging effect is achieved. By applying the optical system to the imaging device and the terminal device, the functions of the imaging device and the terminal device are enhanced, and the user experience is improved.

Description

Technical Field

[0001] The present application relates to the field of optical imaging technology, and in particular to an optical system, an imaging device and a terminal device. Background Art

[0002] As people's demand for taking photos with terminal devices such as mobile phones increases, higher requirements are placed on the quality and diversity of lens imaging in the field of view environment, such as larger chip size, larger aperture, smaller image distortion, etc. In order to meet user requirements, camera modules are gradually developing in the direction of larger chips, larger apertures, and smaller distortion.

[0003] At present, mobile phone camera modules often use ultra-wide-angle imaging systems. The large viewing angle and limited structural size make it difficult to compress the ultra-wide-angle lens design to a lower level. This has caused the ultra-wide-angle imaging systems of some mobile phones on the market to have large optical distortions, and these optical distortions can be clearly perceived by users during actual use or require distortion correction to be turned on. The distortion of ultra-wide-angle lenses on the market is generally less than -10%. However, in the application of terminal devices, when using an ultra-wide-angle lens to record video, the video image will be corrected for distortion in real time, which will consume a lot of processing resources in the terminal device, which is a great challenge to the power consumption and processing speed of the device.

[0004] Therefore, there is an urgent need for an ultra-wide-angle lens that can optimize optical imaging quality and reduce optical distortion to meet market demand. Summary of the invention

[0005] The present application provides an optical system, an imaging device and a terminal device to solve the problems of the prior art.

[0006] In the first aspect, the present application provides an optical system, including: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens arranged in sequence along the optical axis from the object plane to the image plane; the first lens, the second lens, the fourth lens and the seventh lens have negative optical focal length; the third lens and the fifth lens have positive optical focal length; the sixth lens has optical focal length; wherein at least one of the first lens, the second lens, the fourth lens, the sixth lens and the seventh lens has a non-rotationally symmetric aspherical surface. Through the scheme provided in this embodiment, the non-rotationally symmetric aspherical surface is set on the lens with negative optical focal length to reduce the distortion of the image on the image plane, so as to achieve the ultra-wide-angle and small-distortion imaging effect of the optical system, and scenes such as recording videos and taking photos for preview do not require algorithm distortion correction.

[0007] In a possible design, the non-rotationally symmetric aspheric surface is disposed on the seventh lens. Through the solution provided by this embodiment, the non-rotationally symmetric aspheric surface of the seventh lens plays a role in correcting aberrations.

[0008] In a possible design, the TV distortion of the image formed by the optical system on the image plane is TDT, which satisfies the following formula: |TDT|≤3.0%. Through the solution provided in this embodiment, the TV distortion TDT is controlled below 3.0%, further reducing the distortion.

[0009] In a possible design, the maximum range of the image formed by the optical system on the image plane has a length of Imgx in the x direction and a length of Imgy in the y direction, and the half image height of the image is Imgy / Imgx, which satisfies the following formula: Imgy / Imgx=0.75. The solution provided in this embodiment improves the imaging quality and increases the shooting competitiveness of the smart terminal device.

[0010] In a possible design, the field of view of the optical system is FOV, which satisfies the following formula: 100°≤FOV≤130°. The solution provided in this embodiment realizes the ultra-wide-angle function.

[0011] In a possible design, an aperture is provided between the second lens and the third lens. The solution provided in this embodiment determines the amount of light entering the lens and the F number of the optical system, which helps to reduce the F number and increase the aperture.

[0012] In a possible design, the total optical length of the optical system is TTL, and half of the length of the diagonal of the imaging area on the image plane is ImgH, which satisfies the following formula: TTL / ImgH≤1.7. Through the solution provided in this embodiment, while reducing the total optical length TTL of the lens, the pixels of the image formed on the image plane are relatively not reduced or not significantly reduced, while ensuring the imaging quality and ultra-wide angle, the lens thickness is thin, which can save more space in the terminal device.

[0013] In a possible design, the fifth lens has a fifth object side and a fifth image side. The fifth object side has a fifth object side edge away from the optical axis and a fifth object side center located on the optical axis. The fifth image side has a fifth image side edge away from the optical axis and a fifth image side center located on the optical axis. The fifth object side and the fifth image side are respectively curved towards the object plane with respect to the fifth object side center and the fifth image side center. The fifth object side center and the fifth image side center are respectively convex towards the image plane with respect to the fifth object side edge and the fifth image side edge. The radius of curvature R9 of the fifth object side is greater than the radius of curvature R10 of the fifth image side, and 4.7 ≤ R9 / R10 ≤ 5.7 is satisfied. Through the solution provided in this embodiment, the fifth lens performs secondary convergence on the light rays to control the size of the light spot.

[0014] In a possible design, the sixth lens has a sixth object side and a sixth image side. The sixth object side has a sixth object side edge away from the optical axis and a sixth object side center located on the optical axis. The sixth image side has a sixth image side edge away from the optical axis and a sixth image side center located on the optical axis. The regions of the sixth object side near the sixth object side edge and the regions of the sixth image side near the sixth image side edge are respectively curved towards the object plane. The sixth object side center and the sixth image side center both protrude towards the object plane. The effective focal length f6 of the sixth lens and the effective focal length fx of the optical system in the x-axis direction satisfy -6.5 < f6 / fx ≤ 5.5. Through the solution provided in this embodiment, the sixth lens performs secondary divergence and redistribution on the converged light rays, so that the light intensity distribution of the light spot formed by the light rays exiting the sixth lens is more uniform.

[0015] In a possible design, the seventh lens has a seventh object side and a seventh image side. The seventh object side has a seventh object side edge away from the optical axis and a seventh object side center located on the optical axis. The seventh image side has a seventh image side edge away from the optical axis and a seventh image side center located on the optical axis. The regions of the seventh object side near the seventh object side edge and the regions of the seventh image side near the seventh image side edge are respectively curved towards the image plane. The seventh object side center and the seventh image side center both protrude towards the object plane. The radius of curvature R13 of the seventh object side and the radius of curvature R14 of the seventh image side satisfy 1.4 ≤ R13 / R14 ≤ 1.7. Through the solution provided in this embodiment, the seventh lens performs triple divergence and secondary redistribution on the light rays that have undergone secondary divergence and redistribution, so that the pixel point distribution of the image formed on the image plane is uniform, the distortion is smaller, and the imaging quality is higher.

[0016] Through the solution provided in this embodiment, high-quality imaging performance is achieved by reasonably allocating the optical powers of the fifth lens, the sixth lens, and the seventh lens.

[0017] In a possible design, the effective focal length of the optical system in the x-axis direction of the plane perpendicular to the optical axis is fx, the effective focal length in the y-axis direction of the plane perpendicular to the optical axis is fy, and the entrance pupil diameter is EPD, which satisfies the following formula: fx / EPD=2.0, fy / EPD=2.0. Through the solution provided in this embodiment, the aperture number is set to 2.0, which can increase the shutter speed, so that the lens has a large amount of light entering and a wider range of applications.

[0018] In a possible design, the third lens has a third image side surface, the curvature radius of the third image side surface in the y-axis direction of the plane perpendicular to the optical axis is R6, the fifth lens has a fifth image side surface, the curvature radius of the fifth image side surface in the y-axis direction of the plane perpendicular to the optical axis is R10, and the effective focal length of the optical system in the y-axis direction of the plane perpendicular to the optical axis is fy, which satisfies the following formula: -0.75≤(R6-R10) / fy≤-0.5. Through the solution provided in this embodiment, the first convergence of the third lens and the second convergence of the fifth lens can enlarge the light spot.

[0019] In a possible design, the seventh lens has a seventh object side surface and a seventh image side surface, and the seventh object side surface and the seventh image side surface are respectively centrally symmetrical about the optical axis. Through the solution provided by this embodiment, the seventh object side surface of the seventh lens is centrally symmetrical about the optical axis, ensuring that the light incident on the seventh image side surface of the seventh lens is centrally symmetrical about the optical axis, and the seventh image side surface of the seventh lens is centrally symmetrical about the optical axis, ensuring that the image formed on the image plane is in the middle of the image plane and is also centrally symmetrical about the optical axis.

[0020] In a second aspect, the present application provides an imaging device, which includes the optical system provided in the first aspect. By setting the optical system provided in the first aspect in the imaging device, the lens length of the imaging device can be shortened, and the field of view angle can be increased and the distortion can be reduced while ensuring that the image size of the image plane remains basically unchanged, thereby realizing an imaging device that combines ultra-wide angle and small distortion.

[0021] In a third aspect, the present application provides a terminal device, which includes the imaging device provided in the second aspect. By providing the imaging device having the optical system provided in the first aspect in the terminal device, various shooting application scenarios under different large fields of view can be realized, thereby enhancing the functions of the terminal device and improving the user experience.

[0022] It can be seen that in all the above aspects, by introducing a non-rotationally symmetric aspheric lens into the optical system, the design freedom is increased, which is beneficial to improving the imaging quality of the lens in a compact system and achieving ultra-wide-angle and small distortion imaging effects. Scenarios such as recording videos and taking photos for preview do not require distortion correction algorithms, and can be used for terminal devices to shoot and record images, such as using lenses of portable electronic products such as mobile phones, tablets, and monitors to shoot external videos and photos, including various shooting application scenarios under different large fields of view. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of an optical system provided in Example 1 of the present application;

[0024] Figure 2 A schematic diagram of grid distortion of an image formed on an image plane in an optical system provided in Example 1 of the present application;

[0025] Figure 3 A schematic diagram of an optical system provided in Example 2 of the present application;

[0026] Figure 4 A schematic diagram of grid distortion of an image formed on an image plane in an optical system provided in 2 of the present application;

[0027] Figure 5 A schematic diagram of an optical system provided in Example 3 of the present application;

[0028] Figure 6 A schematic diagram of grid distortion of an image formed on an image plane in an optical system provided in 3 of the present application;

[0029] Figure 7 A schematic diagram of an optical system provided in Example 4 of the present application;

[0030] Figure 8 A schematic diagram of grid distortion of an image formed on an image plane in an optical system provided in 4 of the present application;

[0031] Fig. 9 A schematic diagram of an optical system provided in Example 5 of the present application;

[0032] Fig.10 A schematic diagram of grid distortion of an image formed on an image plane in an optical system provided in 5 of the present application;

[0033] Fig.11 A schematic diagram of an optical system provided in Example 6 of the present application;

[0034] Fig.126 provided in the present application is a schematic diagram of grid distortion of an image formed on an image plane in an optical system.

[0035] Reference numerals:

[0036] 1- first lens;

[0037] 2- Second lens;

[0038] 3- the third lens;

[0039] 4- the fourth lens;

[0040] 5-fifth lens;

[0041] 6-sixth lens;

[0042] 7-seventh lens;

[0043] 8-object plane;

[0044] 9- aperture;

[0045] 10- filter;

[0046] 11-optical axis;

[0047] S1-first object side;

[0048] S2- first image side;

[0049] S3-second object side;

[0050] S4-second image side;

[0051] S5-third object side;

[0052] S6-third image side;

[0053] S7-fourth object side;

[0054] S8-Fourth image side view;

[0055] S9- fifth object side;

[0056] S10- fifth image side view;

[0057] S11-Sixth object side;

[0058] S12-sixth image side view;

[0059] S13-Seventh object side;

[0060] S14-Seventh image side view;

[0061] S15 - object side of the filter;

[0062] S16-filter image side view;

[0063] S17-Image plane. DETAILED DESCRIPTION

[0064] The terms used in the implementation section of this application are only used to explain the specific embodiments of this application and are not intended to limit this application.

[0065] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0066] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0067] It should be noted that the directional words such as "upper", "lower", "left", and "right" described in the embodiments of the present application are described at the angles shown in the accompanying drawings and should not be understood as limiting the embodiments of the present application. In addition, in the context, it is also necessary to understand that when it is mentioned that an element is connected to another element "upper" or "lower", it can not only be directly connected to another element "upper" or "lower", but also indirectly connected to another element "upper" or "lower" through an intermediate element.

[0068] Please refer to the attached Figure 1-12 ,in, Figure 1 A schematic diagram of an optical system provided in Example 1 of the present application; Figure 2 A schematic diagram of grid distortion of an image formed on an image plane in an optical system provided in Example 1 of the present application; Figure 3 A schematic diagram of an optical system provided in Example 2 of the present application; Figure 4 A schematic diagram of grid distortion of an image formed on an image plane in an optical system provided in 2 of the present application; Figure 5 A schematic diagram of an optical system provided in Example 3 of the present application; Figure 6 A schematic diagram of grid distortion of an image formed on an image plane in an optical system provided in 3 of the present application;

[0069] Figure 7 A schematic diagram of an optical system provided in Example 4 of the present application; Figure 8 A schematic diagram of grid distortion of an image formed on an image plane in an optical system provided in 4 of the present application; Fig. 9 A schematic diagram of an optical system provided in Example 5 of the present application; Fig.10 A schematic diagram of grid distortion of an image formed on an image plane in an optical system provided in 5 of the present application; Fig.11 A schematic diagram of an optical system provided in Example 6 of the present application; Fig.12 6 provided in the present application is a schematic diagram of grid distortion of an image formed on an image plane in an optical system.

[0070] Different from the lenses of professional SLR cameras, the lenses suitable for terminal devices are highly limited. In order to meet the basic photography needs of users, ultra-wide-angle lenses are often used for terminal devices.

[0071] like Figure 1 , 3 , 5, 7, 9, and 11 show an optical system provided by embodiments 1 to 6 of the present application. The optical system includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, and a seventh lens 7, which are arranged in sequence on an optical axis 11 from an object plane 8 to an image plane S17. The optical system is composed of a lens group consisting of seven lenses, and the optical focal power of each lens in the lens group is set differently.

[0072] The focal power is equal to the difference between the convergence of the image-side beam and the convergence of the object-side beam, and it characterizes the ability of the optical system to deflect light. If the focal power is positive, the lens has a converging effect, and if the focal power is negative, the lens has a diverging effect.

[0073] Specifically, the first lens 1 has negative optical power, and its first object side surface S1 has a first object side edge away from the optical axis 11 and a first object side center located on the optical axis 11, and the first image side surface S2 of the first lens 1 has a first image side edge away from the optical axis 11 and a first image side center located on the optical axis 11, and the first object side surface S1 and the first image side surface S2 are respectively curved toward the image plane S17 relative to the first object side center and the first image side center, and the first object side edge and the first image side edge are respectively curved toward the image plane S17 relative to the first object side center and the first image side center. The first lens 1 is set to a structure in which the periphery and the center are convex toward the image plane S17, so that the first lens 1 can receive more incident light, so that the field angle of the optical system is larger, and a wide-angle function is achieved.

[0074] The second lens 2 has a negative optical power. It has a second object side S3 and a second image side S4, as well as a second object side edge and a second image side edge that are away from the optical axis 11. Both the second object side edge and the second image side edge are curved towards the image plane S17. The second object side S3 and the second image side S4 bulge towards the object plane 8. The radius of curvature of the second object side S3 is greater than that of the second image side S4. The second lens 2 is arranged as a concave lens in a crescent shape with the periphery curved towards the image plane S17 relative to the center, so that the light rays refracted by the first lens 1 are further deflected in a direction away from the optical axis 11 and have a smaller angle with the optical axis 11.

[0075] The third lens 3 has a positive optical power. It has a third object side S5 and a third image side S6. The third object side S5 is a convex surface that bulges towards the object side, and the third image side S6 is a convex surface that bulges towards the image side. The third lens 3 is arranged as a convex lens with two convex surfaces to converge the light rays that are further deflected by the second lens 2 and have a smaller angle with the optical axis 11.

[0076] The fourth lens 4 has a negative optical power. It has a fourth object side S7 and a fourth image side S8. The fourth object side S7 has a fourth object side edge away from the optical axis 11 and a fourth object side center located on the optical axis 11. The fourth image side S8 has a fourth image side edge away from the optical axis 11 and a fourth image side center located on the optical axis 11. The fourth object side edge and the fourth image side edge are respectively curved towards the object plane 8 relative to the fourth object side center and the fourth image side center. The fourth object side S7 and the fourth image side S8 both bulge towards the image plane S17. The radius of curvature of the fourth object side S7 is smaller than that of the fourth image side S8. The fourth lens 4 is arranged as a concave lens in a crescent shape with the periphery curved towards the object plane 8 relative to the center to deflect the light rays converged by the third lens 3, so that the light rays diverge in a direction away from the optical axis 11.

[0077] The fifth lens 5 has a positive optical power. It has a fifth object side S9 and a fifth image side S10. The fifth object side S9 has a fifth object side edge away from the optical axis 11 and a fifth object side center located on the optical axis 11. The fifth image side S10 has a fifth image side edge away from the optical axis 11 and a fifth image side center located on the optical axis 11. The fifth object side S9 and the fifth image side S10 are respectively curved towards the object plane 8 relative to the fifth object side center and the fifth image side center. The fifth object side center and the fifth image side center are respectively curved towards the image plane S17 relative to the fifth object side edge and the fifth image side edge. The radius of curvature R9 of the fifth object side S9 is greater than the radius of curvature R10 of the fifth image side S10, satisfying 4.7 < R9 / R10 < 5.7. The fifth lens 5 is arranged as a convex lens with the periphery curved towards the object plane 8 and two convex surfaces bulging towards the image plane S17 to perform secondary convergence on the light rays diverged by the fourth lens 4, so that the light rays propagate in a direction towards the optical axis 11 to control the size of the light spot.

[0078] The sixth lens 6 has a focal power, i.e., its focal power can be positive or negative. Its sixth object side S11 has a sixth object side edge away from the optical axis 11 and a sixth object side center located on the optical axis 11. The sixth image side S12 of the sixth lens 6 has a sixth image side edge away from the optical axis 11 and a sixth image side center located on the optical axis 11. The regions of the sixth object side S11 near the sixth object side edge and the sixth image side S12 near the sixth image side edge are each curved toward the object surface 8. The sixth object side edge and the sixth image side edge are each curved toward the object surface 8 relative to the sixth object side center and the sixth image side center. The sixth object side center and the sixth image side center both protrude toward the object surface 8. The effective focal length f6 of the sixth lens 6 and the effective focal length fx of the lens group in the x-axis direction satisfy -6.5 < f6 / fx ≤ 5.5. The sixth lens 6 is configured with a structure where the periphery is curved toward the object surface 8 and the center protrudes toward the object surface 8, performing secondary divergence and redistribution of the light rays that are converged by the fifth lens 5, so that the light intensity distribution of the light spot formed by the light rays exiting the sixth lens 6 is more uniform.

[0079] The seventh lens 7 has a negative focal power. Its seventh object side S13 has a seventh object side edge away from the optical axis 11 and a seventh object side center located on the optical axis 11. The seventh image side S14 of the seventh lens 7 has a seventh image side edge away from the optical axis 11 and a seventh image side center located on the optical axis 11. The regions of the seventh object side S13 near the seventh object side edge and the seventh image side S14 near the seventh image side edge are each curved toward the object surface 8. The seventh object side edge and the seventh image side edge are each curved toward the object surface 8 relative to the seventh object side center and the seventh image side center. The seventh object side center and the seventh image side center both protrude toward the object surface 8. The radius of curvature R13 of the seventh object side S13 and the radius of curvature R14 of the seventh image side S14 satisfy 1.4 < R13 / R14 < 1.7. The seventh lens 7 is configured with a structure where the periphery is curved toward the object surface 8 and the center protrudes toward the object surface 8, performing tertiary divergence and secondary redistribution of the light rays that are secondarily diverged and redistributed by the sixth lens 6, so that the pixel point distribution of the image formed on the image surface S17 after exiting the seventh lens 7 is uniform, the distortion is smaller, and the imaging quality is higher.

[0080] In this optical system, at least one of the first lens 1, the second lens 2, the fourth lens 4, the sixth lens 6, and the seventh lens 7 has an aspherical surface that is non-rotationally symmetric. Specifically, among the five lenses with negative focal power, non-rotationally symmetric aspherical surfaces are provided, and the number can vary from 1 to 10. According to permutations and combinations, there are countless configuration schemes. The aspherical surface that is non-rotationally symmetric of the lens is the object side and / or the image side of the lens. The surfaces of the other lenses without non-rotationally symmetric aspherical surfaces can be configured as spherical surfaces or aspherical surfaces commonly used in the prior art, such as Q-type aspherical surfaces.

[0081] The present application preferably takes the seventh object-side surface S13 and the seventh image-side surface S14 of the seventh lens 7 as non-rotationally symmetric aspherical surfaces, and the twelve surfaces of the first lens 1 to the sixth lens 6 are all Q-type aspherical surfaces as an example for explanation, but this is only for the convenience of explanation and does not limit the scope of protection of the present application.

[0082] In the optical system, the surface shapes of the twelve Q-type aspheric surfaces of the first lens 1 to the sixth lens 6 may satisfy but are not limited to being defined by the following aspheric surface formula:

[0083]

[0084] Among them, z is the aspheric height, r is the radial coordinate of the aspheric surface, c is the vertex spherical curvature of the aspheric surface, K is the quadratic surface constant, and a m is the aspheric coefficient, r max is the maximum radial radius coordinate, u=r / r max .

[0085] The surface shape of the non-rotationally symmetric aspherical surface of the seventh lens 7 is defined by the following aspherical surface formula:

[0086]

[0087] Among them, z is the vector height parallel to the z-axis; N is the total number of polynomial coefficients in the series, Ai is the coefficient of the i-th expanded polynomial, r is the radial coordinate of the aspheric surface, c is the vertex spherical curvature of the aspheric surface, and K is the quadratic surface constant.

[0088] The TV distortion of the image formed on the image plane S17 by the optical system is TDT. TV distortion is a relative distortion, that is, the degree of deformation of the actual image. The optical system can control the TV distortion TDT below 3.0%, reduce the distortion of the image on the image plane S17, and achieve the ultra-wide-angle and small-distortion imaging effect of the optical system. No algorithm is required for distortion correction in scenes such as recording videos and taking photos.

[0089] Furthermore, in the optical system, the maximum range of the image formed by the imaging area of ​​the optical system on the image plane S17 has a length in the x direction of Imgx and a length in the y direction of Imgy, and the half image height of the image is Imgy / Imgx, which satisfies the following formula: Imgy / Imgx=0.75, and an imaging area with a resolution of 4:3 is formed on the image plane S17, thereby improving the imaging quality and increasing the shooting competitiveness of the smart terminal device.

[0090] The angle between the edge of the area where the first object side surface S1 of the first lens 1 can receive the light emitted from the object plane 8 and the two straight lines between the first object side edge of the first lens 1 is called the field of view angle FOV of the optical system, which satisfies the following formula: 100°≤FOV≤130°, realizing the ultra-wide-angle function.

[0091] Furthermore, an aperture 9 is provided between the second lens 2 and the third lens 3, and the aperture 9 determines the amount of light entering the lens and the F number of the optical system, which helps to reduce the F number and increase the aperture. The F number is the aperture number, and the aperture is a device used to control the amount of light that passes through the lens and irradiates the photosensitive element. The aperture size is expressed by the F number / F value, and the aperture F number is a relative value obtained by the focal length of the lens / the diameter of the lens (the inverse of the relative aperture).

[0092] Furthermore, the total optical length of the optical system is TTL, and half of the length of the diagonal of the imaging area on the image plane S17 is ImgH, which satisfies the following formula: 1.2≤TTL / ImgH≤1.7. The diagonal of the imaging area on the image plane S17 is the diagonal of the rectangular area with a resolution of 4:3. By limiting the ratio of the total optical length to the imaging area to the range of 1.2 to 1.7, while reducing the total optical length TTL of the lens, the pixels of the image formed on the image plane S17 are relatively not reduced or not significantly reduced. While ensuring the imaging quality, the lens can be made smaller, thereby achieving an ultra-wide angle.

[0093] In this optical system, the effective focal length of the optical system in the x-axis direction of the plane perpendicular to the optical axis 11 is fx, the effective focal length in the y-axis direction of the plane perpendicular to the optical axis 11 is fy, and the entrance pupil diameter is EPD, which satisfies the following formula: fx / EPD=2.0, fy / EPD=2.0. At this time, the aperture number of the lens group is set to 2.0, which can increase the shutter speed, so that the amount of light entering the lens is large and the application range is wider.

[0094] In the optical system, the third lens 3 has a third image side surface S6, and the curvature radius of the third image side surface S6 in the y-axis direction of the plane perpendicular to the optical axis 11 is R6. The fifth lens 5 has a fifth image side surface S10, and the curvature radius of the fifth image side surface S10 in the y-axis direction of the plane perpendicular to the optical axis 11 is R10. The effective focal length of the optical system in the y-axis direction of the plane perpendicular to the optical axis 11 is fy, which satisfies the following formula: -0.75≤(R6-R10) / fy≤-0.5, indicating that the convexity of the third image side surface S6 of the third lens 3 is smaller than that of the fifth image side surface S10 of the fifth lens 5. After the light is transmitted, the first convergence of the third lens 3 and the second convergence of the fifth lens 5 can enlarge the light spot.

[0095] In the optical system, the seventh lens 7 has a seventh object-side surface S13 and a seventh image-side surface S14 , and the seventh object-side surface S13 and the seventh image-side surface S14 are respectively centrally symmetric with respect to the optical axis 11 .

[0096] Specifically, the on-axis distance from the intersection of the seventh object side surface S13 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to the effective radius vertex of the seventh object side surface S13 is sag11(x); the on-axis distance from the intersection of the seventh object side surface S13 with the optical axis 11 in the y-axis direction perpendicular to the optical axis 11 to the effective radius vertex of the seventh object side surface S13 is sag11(y); sag11(x) is symmetric about the y-axis, and sag11(y) is symmetric about the x-axis, satisfying: sag11(x)=sag11(-x), sag11(y)=sag11(-y). The axial distance from the intersection of the seventh image side surface S14 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to the effective radius vertex of the seventh image side surface S14 is sag12(x); the y-axis distance from the intersection of the seventh image side surface S14 with the optical axis 11 in the axial direction perpendicular to the optical axis 11 to the effective radius vertex of the seventh image side surface S14 is sag12(y); sag12(x) is symmetric about the y-axis, and sag12(y) is symmetric about the x-axis, satisfying: sag12(x)=sag12(-x), sag12(y)=sag12(-y).

[0097] The seventh lens 7 is configured as above to make the seventh object-side surface S13 symmetrical about the optical axis 11, to ensure that the light incident on the seventh image-side surface S14 of the seventh lens 7 is symmetrical about the optical axis 11, and the seventh image-side surface S14 is symmetrical about the optical axis 11, to ensure that the image formed on the image plane S17 is in the center of the image plane S17 and is also symmetrical about the optical axis 11.

[0098] Example 1

[0099] like Figure 1As shown, Example 1 of the present application provides an optical system, which has an object plane 8, an image plane S17, an aperture 9, a filter 10 and a lens group consisting of seven lenses. Along the optical axis 11 from the object plane 8 to the image plane S17, a first lens 1, a second lens 2, an aperture 9, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7 and a filter 10 are arranged in sequence. Among them, the ratio of the focal length f1 of the first lens 1 to the effective focal length ft of the lens group is |f1 / ft|=7.328, the ratio of the focal length f2 of the second lens 2 to the effective focal length ft of the lens group is |f2 / ft|=37.864, the ratio of the focal length f3 of the third lens 3 to the effective focal length ft of the lens group is |f3 / ft|=1.473, the ratio of the focal length f4 of the fourth lens 4 to the effective focal length ft of the lens group is |f4 / ft|=3.717, the ratio of the focal length f5 of the fifth lens 5 to the effective focal length ft of the lens group is |f5 / ft|=1.058, the ratio of the focal length f6 of the sixth lens 6 to the effective focal length ft of the lens group is |f6 / ft|=4.654, and the ratio of the focal length f7 of the seventh lens 7 to the effective focal length ft of the lens group is |f7 / ft|=3.663.

[0100] The seventh object-side surface S13 and the seventh image-side surface S14 of the seventh lens 7 are both non-rotationally symmetric aspherical surfaces, and the maximum value TDT of TV distortion within the imaging range of the lens group satisfies |TDT|=2.20%.

[0101] The first lens 1 receives light from the object plane 8 and refracts it to the second lens 2 behind it. The range of light that it can receive is the maximum field of view FOV of the lens group. In this embodiment 1, FOV=122°.

[0102] The effective focal length ft of the lens group has two components in the direction perpendicular to the optical axis 11, namely the effective focal length fx in the x-axis direction and the effective focal length fy in the y-axis direction. The ratio of the entrance pupil diameter EPD of the lens group to fx and fy is the aperture F number Fno, and Fno satisfies fx / EPD=2.0, fy / EPD=2.0.

[0103] The distance from the first object-side surface S1 of the first lens 1 of the lens group to the image plane S17 of the lens group on the optical axis 11 is the total optical length TTL, and half of the diagonal length of the effective pixel area on the image plane S17 of the lens group is ImgH, satisfying TTL / ImgH=1.34.

[0104] The curvature radius of the fifth object-side surface S9 of the fifth lens 5 is R9, and the curvature radius of the fifth image-side surface S10 of the fifth lens 5 is R10, satisfying R9 / R10=4.925. The middle thickness of the fifth lens 5 is much greater than the peripheral thickness, thereby enhancing the secondary convergence of light.

[0105] The curvature radius of the sixth object-side surface S11 of the sixth lens 6 is R11, and the curvature radius of the sixth image-side surface S12 of the sixth lens 6 is R12, satisfying R11 / R12=1.595. The sixth lens 6 appropriately diffuses and amplifies the light.

[0106] The curvature radius R13 of the seventh object-side surface S13 of the seventh lens 7 and the curvature radius R14 of the seventh image-side surface S14 of the seventh lens 7 satisfy R13 / R14=1.529. The seventh lens 7 appropriately diffuses and amplifies the light and corrects the aberration of the light by using the non-rotationally symmetric aspherical surface, so that the image quality formed on the image plane S17 is higher.

[0107] The curvature radius R6 of the third image side surface S6 of the third lens 3 in the y-axis direction perpendicular to the optical axis 11, the curvature radius R10 of the fifth image side surface S10 of the fifth lens in the y-axis direction perpendicular to the optical axis 11, and the effective focal length fy in the Y-axis direction of the imaging lens satisfy: (R6-R10) / fy=-0.588.

[0108] The on-axis distance from the intersection of the seventh object side surface S13 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to the vertex of the effective radius of the seventh object side surface S13 is sag11(x); the on-axis distance from the intersection of the seventh object side surface S13 with the optical axis 11 in the y-axis direction perpendicular to the optical axis 11 to the vertex of the effective radius of the seventh object side surface S13 is sag11(y); sag11(x) is symmetric about the y-axis, and sag11(y) is symmetric about the x-axis, satisfying: sag11(x)=sag11(-x), sag11(y)=sag11(-y). The axial distance from the intersection of the seventh image side surface S14 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to the effective radius vertex of the seventh image side surface S14 is sag12(x); the y-axis distance from the intersection of the seventh image side surface S14 with the optical axis 11 in the axial direction perpendicular to the optical axis 11 to the effective radius vertex of the seventh image side surface S14 is sag12(y); sag12(x) is symmetric about the y-axis, and sag12(y) is symmetric about the x-axis, satisfying: sag12(x)=sag12(-x), sag12(y)=sag12(-y).

[0109] In the optical system of the present embodiment 1, the object plane 8 is a plane, the first object-side surface S1 and the first image-side surface S2 of the first lens 1, the second object-side surface S3 and the second image-side surface S4 of the second lens 2, the third object-side surface S5 and the third image-side surface S6 of the third lens 3, the fourth object-side surface S7 and the fourth image-side surface S8 of the fourth lens 4, the fifth object-side surface S9 and the fifth image-side surface S10 of the fifth lens 5, the sixth object-side surface S11 and the sixth image-side surface S12 of the sixth lens 6 are Q-type aspherical surfaces, the seventh object-side surface S13 and the seventh image-side surface S14 of the seventh lens 7 are XY polynomial type non-rotationally symmetric aspherical surfaces, the filter 10 has a certain thickness, the filter object-side surface S15 and the filter image-side surface S16 are both planes, and the image plane S17 is a plane.

[0110] The surface shape of the Q-type aspheric surface can satisfy but is not limited to the following aspheric surface formula:

[0111]

[0112] Among them, z is the aspheric height, r is the radial coordinate of the aspheric surface, c is the vertex spherical curvature of the aspheric surface, K is the quadratic surface constant, and a m is the aspheric coefficient, r max is the maximum radial radius coordinate, u=r / r max .

[0113] The surface shape of the non-rotationally symmetric aspherical surface of the seventh lens 7 is defined by the following aspherical surface formula:

[0114]

[0115] Among them, z is the vector height parallel to the z-axis; N is the total number of polynomial coefficients in the series, Ai is the coefficient of the i-th expanded polynomial, r is the radial coordinate of the aspheric surface, c is the vertex spherical curvature of the aspheric surface, and K is the quadratic surface constant.

[0116] The basic parameters of the optical system of this embodiment 1 are shown in Tables 1a to 1d. Table 1a shows the parameters of each surface, where R is the radius of curvature, Th is the surface thickness, nd is the refractive index of the surface material, vd is the Abbe coefficient of the surface material, and f' is the focal length, all of which are in millimeters (mm). Table 1b shows the parameters of each lens, where f1 to f7 are the effective focal lengths of each lens, TTL is the total optical length of the optical system, half of the diagonal length of the effective pixel area on the image plane S17 is ImgH, the maximum field of view is FOV, the aperture number of the optical imaging system is Fno, and the effective focal length of the lens group is EFL. Table 1c shows the aspheric parameters of each lens. Table 1d shows the aspheric parameters of a lens with a non-rotationally symmetric aspheric surface.

[0117]

[0118] Table 1a

[0119]

[0120]

[0121] Table 1b

[0122]

[0123]

[0124] Table 1c

[0125]

[0126]

[0127]

[0128] Table 1d

[0129] The basic parameters used in Table 1a to Table 1d are used to design the optical system of this embodiment 1, forming Figure 1 The optical system architecture shown in the figure makes full use of the mutual cooperation of the positive and negative transformation of the optical power among the seven lenses, and realizes the ultra-wide-angle and small-distortion ultra-wide-angle lens through the aberration correction and distortion reduction function of the non-rotationally symmetric aspherical surface on the light. Figure 2 As shown in FIG. 1 , the distortion of the image formed by the object on the image plane S17 through the optical system of this embodiment 1 is pincushion distortion, and the distortion is controlled within 2.20%. Figure 2 In the figure, the square solid grid is the ideal image formed under ideal conditions. The image of the object corresponding to the intersection of the solid grid through the optical system of this embodiment 1 is the pixel points suspended around the solid grid. It can be seen that the actual image has a pincushion distortion relative to the solid grid, but the degree of distortion is not large. The pixel points are basically close to the solid grid, which well achieves the purpose of this embodiment 1.

[0130] Example 2

[0131] like Figure 3As shown, Example 2 of the present application provides an optical system, which has an object plane 8, an image plane S17, an aperture 9, a filter 10 and a lens group consisting of seven lenses. Along the optical axis 11 from the object plane 8 to the image plane S17, a first lens 1, a second lens 2, an aperture 9, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7 and a filter 10 are arranged in sequence. Among them, the ratio of the focal length f1 of the first lens 1 to the effective focal length ft of the lens group is |f1 / ft|=7.395, the ratio of the focal length f2 of the second lens 2 to the effective focal length ft of the lens group is |f2 / ft|=40.943, the ratio of the focal length f3 of the third lens 3 to the effective focal length ft of the lens group is |f3 / ft|=1.484, the ratio of the focal length f4 of the fourth lens 4 to the effective focal length ft of the lens group is |f4 / ft|=3.744, the ratio of the focal length f5 of the fifth lens 5 to the effective focal length ft of the lens group is |f5 / ft|=1.069, the ratio of the focal length f6 of the sixth lens 6 to the effective focal length ft of the lens group is |f6 / ft|=4.712, and the ratio of the focal length f7 of the seventh lens 7 to the effective focal length ft of the lens group is |f7 / ft|=3.202.

[0132] The seventh object-side surface S13 and the seventh image-side surface S14 of the seventh lens 7 are both non-rotationally symmetric aspherical surfaces, and the maximum value TDT of TV distortion within the imaging range of the lens group satisfies |TDT|=2.23%.

[0133] The first lens 1 receives light from the object plane 8 and refracts it to the second lens 2 behind it. The range of light that it can receive is the maximum field of view FOV of the lens group. In this embodiment 2, FOV=122°.

[0134] The effective focal length ft of the lens group has two components in the direction perpendicular to the optical axis 11, namely the effective focal length fx in the x-axis direction and the effective focal length fy in the y-axis direction. The ratio of the entrance pupil diameter EPD of the lens group to fx and fy is the aperture number Fno, and Fno satisfies fx / EPD=2.0, fy / EPD=2.0.

[0135] The distance from the first object-side surface S1 of the first lens 1 of the lens group to the image plane S17 of the lens group on the optical axis 11 is the total optical length TTL, and half of the diagonal length of the effective pixel area on the image plane S17 of the lens group is ImgH, satisfying TTL / ImgH=1.325.

[0136] The curvature radius of the fifth object-side surface S9 of the fifth lens 5 is R9, and the curvature radius of the fifth image-side surface S10 of the fifth lens 5 is R10, satisfying R9 / R10=4.873. The middle thickness of the fifth lens 5 is much greater than the peripheral thickness, thereby enhancing the secondary convergence of light.

[0137] The curvature radius of the sixth object-side surface S11 of the sixth lens 6 is R11, and the curvature radius of the sixth image-side surface S12 of the sixth lens 6 is R12, satisfying R11 / R12=1.592. The sixth lens 6 appropriately diffuses and amplifies the light.

[0138] The curvature radius R13 of the seventh object-side surface S13 of the seventh lens 7 and the curvature radius R14 of the seventh image-side surface S14 of the seventh lens 7 satisfy R13 / R14=1.523. The seventh lens 7 appropriately diffuses and amplifies the light and corrects the aberration of the light by using the non-rotationally symmetric aspherical surface, so that the image quality formed on the image plane S17 is higher.

[0139] The curvature radius R6 of the third image side surface S6 of the third lens 3 in the y-axis direction perpendicular to the optical axis 11, the curvature radius R10 of the fifth image side surface S10 of the fifth lens in the y-axis direction perpendicular to the optical axis 11, and the effective focal length fy in the Y-axis direction of the imaging lens satisfy: (R6-R10) / fy=-0.594.

[0140] The on-axis distance from the intersection of the seventh object side surface S13 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to the vertex of the effective radius of the seventh object side surface S13 is sag11(x); the on-axis distance from the intersection of the seventh object side surface S13 with the optical axis 11 in the y-axis direction perpendicular to the optical axis 11 to the vertex of the effective radius of the seventh object side surface S13 is sag11(y); sag11(x) is symmetric about the y-axis, and sag11(y) is symmetric about the x-axis, satisfying: sag11(x)=sag11(-x), sag11(y)=sag11(-y). The axial distance from the intersection of the seventh image side surface S14 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to the effective radius vertex of the seventh image side surface S14 is sag12(x); the y-axis distance from the intersection of the seventh image side surface S14 with the optical axis 11 in the axial direction perpendicular to the optical axis 11 to the effective radius vertex of the seventh image side surface S14 is sag12(y); sag12(x) is symmetric about the y-axis, and sag12(y) is symmetric about the x-axis, satisfying: sag12(x)=sag12(-x), sag12(y)=sag12(-y).

[0141] In the optical system of the present embodiment 2, the object plane 8 is a plane, the first object side surface S1 and the first image side surface S2 of the first lens 1, the second object side surface S3 and the second image side surface S4 of the second lens 2, the third object side surface S5 and the third image side surface S6 of the third lens 3, the fourth object side surface S7 and the fourth image side surface S8 of the fourth lens 4, the fifth object side surface S9 and the fifth image side surface S10 of the fifth lens 5, the sixth object side surface S11 and the sixth image side surface S12 of the sixth lens 6 are Q-type aspherical surfaces, the seventh object side surface S13 and the seventh image side surface S14 of the seventh lens 7 are XY polynomial type non-rotationally symmetric aspherical surfaces, the filter 10 has a certain thickness, the filter object side surface S15 and the filter image side surface S16 are both planes, and the image plane S17 is a plane.

[0142] The surface shape of the Q-type aspheric surface can satisfy but is not limited to the following aspheric surface formula:

[0143]

[0144] Among them, z is the aspheric height, r is the radial coordinate of the aspheric surface, c is the vertex spherical curvature of the aspheric surface, K is the quadratic surface constant, and a m is the aspheric coefficient, r max is the maximum radial radius coordinate, u=r / r max .

[0145] The surface shape of the non-rotationally symmetric aspherical surface of the seventh lens 7 is defined by the following aspherical surface formula:

[0146]

[0147] Among them, z is the vector height parallel to the z-axis; N is the total number of polynomial coefficients in the series, Ai is the coefficient of the i-th expanded polynomial, r is the radial coordinate of the aspheric surface, c is the vertex spherical curvature of the aspheric surface, and K is the quadratic surface constant.

[0148] The basic parameters of the optical system of this embodiment 2 are shown in Tables 2a to 2d. Table 2a shows the parameters of each surface, wherein R is the radius of curvature, Th is the surface thickness, nd is the refractive index of the surface material, vd is the Abbe coefficient of the surface material, and f' is the focal length, all of which are in millimeters (mm). Table 2b shows the parameters of each lens, wherein f1 to f7 are the effective focal lengths of each lens, TTL is the total optical length of the optical system, half of the diagonal length of the effective pixel area on the image plane S17 is ImgH, the maximum field of view is FOV, the aperture number of the optical imaging system is Fno, and the effective focal length of the lens group is EFL. Table 2c shows the aspheric parameters of each lens. Table 2d shows the aspheric parameters of a lens having a non-rotationally symmetric aspheric surface.

[0149]

[0150] Table 2a

[0151] f1(mm) -21.450 f2(mm) -118.757 f3(mm) 4.305 f4(mm) -10.860 f5(mm) 3.099 f6(mm) -13.667 f7(mm) -9.288 TTL(mm) 6.889 Fno 2.090 ImgH(mm) 5.200 FOV(°) 122 EFL 2.901

[0152] Table 2b

[0153]

[0154]

[0155]

[0156] Table 2c

[0157]

[0158]

[0159] Table 2d

[0160] The basic parameters used in Table 2a to Table 2d are used to design the optical system of this embodiment 2 to form the following Figure 3 The optical system architecture shown in the figure makes full use of the mutual cooperation of the positive and negative transformation of the optical power among the seven lenses, and realizes the ultra-wide-angle and small-distortion ultra-wide-angle lens through the aberration correction and distortion reduction function of the non-rotationally symmetric aspherical surface on the light. Figure 4 As shown in FIG. 1 , the distortion of the image formed by the object on the image plane S17 through the optical system of this embodiment 2 is a pincushion distortion, and the distortion is controlled within 2.23%. Figure 4 In the figure, the square solid grid is the ideal image formed under ideal conditions. The image of the object corresponding to the intersection of the solid grid through the optical system of this embodiment 2 is the pixel points suspended around the solid grid. It can be seen that the actual image has a pincushion distortion relative to the solid grid, but the degree of distortion is not large. The pixel points are basically close to the solid grid, which well achieves the purpose of this embodiment 2.

[0161] Example 3

[0162] like Figure 5As shown, Example 3 of the present application provides an optical system, which has an object plane 8, an image plane S17, an aperture 9, a filter 10 and a lens group consisting of seven lenses. Along the optical axis 11 from the object plane 8 to the image plane S17, a first lens 1, a second lens 2, an aperture 9, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7 and a filter 10 are arranged in sequence. Among them, the ratio of the focal length f1 of the first lens 1 to the effective focal length ft of the lens group is |f1 / ft|=7.353, the ratio of the focal length f2 of the second lens 2 to the effective focal length ft of the lens group is |f2 / ft|=32.444, the ratio of the focal length f3 of the third lens 3 to the effective focal length ft of the lens group is |f3 / ft|=1.485, the ratio of the focal length f4 of the fourth lens 4 to the effective focal length ft of the lens group is |f4 / ft|=3.768, the ratio of the focal length f5 of the fifth lens 5 to the effective focal length ft of the lens group is |f5 / ft|=1.075, the ratio of the focal length f6 of the sixth lens 6 to the effective focal length ft of the lens group is |f6 / ft|=4.690, and the ratio of the focal length f7 of the seventh lens 7 to the effective focal length ft of the lens group is |f7 / ft|=3.764.

[0163] The seventh object-side surface S13 and the seventh image-side surface S14 of the seventh lens 7 are both non-rotationally symmetric aspherical surfaces, and the maximum value TDT of TV distortion within the imaging range of the lens group satisfies |TDT|=2.12%.

[0164] The first lens 1 receives light from the object plane 8 and refracts it to the second lens 2 behind it. The range of light that it can receive is the maximum field of view FOV of the lens group. In this embodiment 1, FOV=122°.

[0165] The effective focal length ft of the lens group has two components in the direction perpendicular to the optical axis 11, namely the effective focal length fx in the x-axis direction and the effective focal length fy in the y-axis direction. The ratio of the entrance pupil diameter EPD of the lens group to fx and fy is the aperture number Fno, and Fno satisfies fx / EPD=2.0, fy / EPD=2.0.

[0166] The distance from the first object-side surface S1 of the first lens 1 of the lens group to the image plane S17 of the lens group on the optical axis 11 is the total optical length TTL, and half of the diagonal length of the effective pixel area on the image plane S17 of the lens group is ImgH, satisfying TTL / ImgH=1.551.

[0167] The curvature radius of the fifth object-side surface S9 of the fifth lens 5 is R9, and the curvature radius of the fifth image-side surface S10 of the fifth lens 5 is R10, satisfying R9 / R10=5.254. The middle thickness of the fifth lens 5 is much greater than the peripheral thickness, thereby enhancing the secondary convergence of light.

[0168] The curvature radius of the sixth object-side surface S11 of the sixth lens 6 is R11, and the curvature radius of the sixth image-side surface S12 of the sixth lens 6 is R12, satisfying R11 / R12=1.598. The sixth lens 6 appropriately diffuses and amplifies the light.

[0169] The curvature radius R13 of the seventh object-side surface S13 of the seventh lens 7 and the curvature radius R14 of the seventh image-side surface S14 of the seventh lens 7 satisfy R13 / R14=1.524. The seventh lens 7 appropriately diffuses and amplifies the light and corrects the aberration of the light by using the non-rotationally symmetric aspherical surface, so that the image quality formed on the image plane S17 is higher.

[0170] The curvature radius R6 of the third image side surface S6 of the third lens 3 in the y-axis direction perpendicular to the optical axis 11, the curvature radius R10 of the fifth image side surface S10 of the fifth lens in the y-axis direction perpendicular to the optical axis 11, and the effective focal length fy in the Y-axis direction of the imaging lens satisfy: (R6-R10) / fy=-0.585.

[0171] The on-axis distance from the intersection of the seventh object side surface S13 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to the vertex of the effective radius of the seventh object side surface S13 is sag11(x); the on-axis distance from the intersection of the seventh object side surface S13 with the optical axis 11 in the y-axis direction perpendicular to the optical axis 11 to the vertex of the effective radius of the seventh object side surface S13 is sag11(y); sag11(x) is symmetric about the y-axis, and sag11(y) is symmetric about the x-axis, satisfying: sag11(x)=sag11(-x), sag11(y)=sag11(-y). The axial distance from the intersection of the seventh image side surface S14 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to the effective radius vertex of the seventh image side surface S14 is sag12(x); the y-axis distance from the intersection of the seventh image side surface S14 with the optical axis 11 in the axial direction perpendicular to the optical axis 11 to the effective radius vertex of the seventh image side surface S14 is sag12(y); sag12(x) is symmetric about the y-axis, and sag12(y) is symmetric about the x-axis, satisfying: sag12(x)=sag12(-x), sag12(y)=sag12(-y).

[0172] In the optical system of the present embodiment 3, the object plane 8 is a plane, the first object side surface S1 and the first image side surface S2 of the first lens 1, the second object side surface S3 and the second image side surface S4 of the second lens 2, the third object side surface S5 and the third image side surface S6 of the third lens 3, the fourth object side surface S7 and the fourth image side surface S8 of the fourth lens 4, the fifth object side surface S9 and the fifth image side surface S10 of the fifth lens 5, the sixth object side surface S11 and the sixth image side surface S12 of the sixth lens 6 are Q-type aspherical surfaces, the seventh object side surface S13 and the seventh image side surface S14 of the seventh lens 7 are XY polynomial type non-rotationally symmetric aspherical surfaces, the filter 10 has a certain thickness, the filter object side surface S15 and the filter image side surface S16 are both planes, and the image plane S17 is a plane.

[0173] The surface shape of the Q-type aspheric surface can satisfy but is not limited to the following aspheric surface formula:

[0174]

[0175] Among them, z is the aspheric height, r is the radial coordinate of the aspheric surface, c is the vertex spherical curvature of the aspheric surface, K is the quadratic surface constant, and a m is the aspheric coefficient, r max is the maximum radial radius coordinate, u=r / r max .

[0176] The surface shape of the non-rotationally symmetric aspherical surface of the seventh lens 7 is defined by the following aspherical surface formula:

[0177]

[0178] Among them, z is the vector height parallel to the z-axis; N is the total number of polynomial coefficients in the series, Ai is the coefficient of the i-th expanded polynomial, r is the radial coordinate of the aspheric surface, c is the vertex spherical curvature of the aspheric surface, and K is the quadratic surface constant.

[0179] The basic parameters of the optical system of this embodiment 3 are shown in Tables 3a to 3d. Table 3a shows the parameters of each surface, wherein R is the radius of curvature, Th is the surface thickness, nd is the refractive index of the surface material, vd is the Abbe coefficient of the surface material, and f' is the focal length, all of which are in millimeters (mm). Table 3b shows the parameters of each lens, wherein f1 to f7 are the effective focal lengths of each lens, TTL is the total optical length of the optical system, half of the diagonal length of the effective pixel area on the image plane S17 is ImgH, the maximum field of view is FOV, the aperture number of the optical imaging system is Fno, and the effective focal length of the lens group is EFL. Table 3c shows the aspheric parameters of each lens. Table 3d shows the aspheric parameters of a lens having a non-rotationally symmetric aspheric surface.

[0180]

[0181]

[0182] Table 3a

[0183] f1(mm) -24.571 f2(mm) -108.420 f3(mm) 4.962 f4(mm) -12.593 f5(mm) 3.594 f6(mm) -15.674 f7(mm) -12.578 TTL(mm) 8.063 Fno 2.043 ImgH(mm) 5.200 FOV(°) 122 EFL 3.342

[0184] Table 3b

[0185]

[0186]

[0187]

[0188] Table 3c

[0189]

[0190]

[0191] Table 3d

[0192] The basic parameters used in Table 3a to Table 3d are used to design the optical system of this embodiment 3 to form the following Figure 5 The optical system architecture shown in the figure makes full use of the mutual cooperation of the positive and negative transformation of the optical power among the seven lenses, and realizes the ultra-wide-angle and small-distortion ultra-wide-angle lens through the aberration correction and distortion reduction function of the non-rotationally symmetric aspherical surface on the light. Figure 6 As shown in FIG. 1 , the distortion of the image formed by the object on the image plane S17 through the optical system of this embodiment 3 is pincushion distortion, and the distortion is controlled within 2.12%. Figure 6 In the figure, the square solid grid is the ideal image formed under ideal conditions. The image of the object corresponding to the intersection of the solid grid through the optical system of this embodiment 3 is the pixel points suspended around the solid grid. It can be seen that the actual image has a pincushion distortion relative to the solid grid, but the degree of distortion is not large. The pixel points are basically close to the solid grid, which well achieves the purpose of this embodiment 3.

[0193] Example 4

[0194] like Figure 7As shown, Example 4 of the present application provides an optical system, which has an object plane 8, an image plane S17, an aperture 9, a filter 10 and a lens group consisting of seven lenses. Along the optical axis 11 from the object plane 8 to the image plane S17, a first lens 1, a second lens 2, an aperture 9, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7 and a filter 10 are arranged in sequence. Among them, the ratio of the focal length f1 of the first lens 1 to the effective focal length ft of the lens group is |f1 / ft|=7.389, the ratio of the focal length f2 of the second lens 2 to the effective focal length ft of the lens group is |f2 / ft|=26.075, the ratio of the focal length f3 of the third lens 3 to the effective focal length ft of the lens group is |f3 / ft|=1.568, the ratio of the focal length f4 of the fourth lens 4 to the effective focal length ft of the lens group is |f4 / ft|=3.978, the ratio of the focal length f5 of the fifth lens 5 to the effective focal length ft of the lens group is |f5 / ft|=1.106, the ratio of the focal length f6 of the sixth lens 6 to the effective focal length ft of the lens group is |f6 / ft|=5.897, and the ratio of the focal length f7 of the seventh lens 7 to the effective focal length ft of the lens group is |f7 / ft|=4.527.

[0195] The seventh object-side surface S13 and the seventh image-side surface S14 of the seventh lens 7 are both non-rotationally symmetric aspherical surfaces, and the maximum value TDT of TV distortion within the imaging range of the lens group satisfies |TDT|=2.88%.

[0196] The first lens 1 receives light from the object plane 8 and refracts it to the second lens 2 behind it. The range of light that it can receive is the maximum field of view FOV of the lens group. In this embodiment 1, FOV=130°.

[0197] The effective focal length ft of the lens group has two components in the direction perpendicular to the optical axis 11, namely the effective focal length fx in the x-axis direction and the effective focal length fy in the y-axis direction. The ratio of the entrance pupil diameter EPD of the lens group to fx and fy is the aperture number Fno, and Fno satisfies fx / EPD=2.0, fy / EPD=2.0.

[0198] The distance from the first object-side surface S1 of the first lens 1 of the lens group to the image plane S17 of the lens group on the optical axis 11 is the total optical length TTL, and half of the diagonal length of the effective pixel area on the image plane S17 of the lens group is ImgH, satisfying TTL / ImgH=1.211.

[0199] The curvature radius of the fifth object-side surface S9 of the fifth lens 5 is R9, and the curvature radius of the fifth image-side surface S10 of the fifth lens 5 is R10, satisfying R9 / R10=4.82. The middle thickness of the fifth lens 5 is much greater than the peripheral thickness, thereby enhancing the secondary convergence of light.

[0200] The curvature radius of the sixth object-side surface S11 of the sixth lens 6 is R11, and the curvature radius of the sixth image-side surface S12 of the sixth lens 6 is R12, satisfying R11 / R12=1.493. The sixth lens 6 appropriately diffuses and amplifies the light.

[0201] The curvature radius R13 of the seventh object-side surface S13 of the seventh lens 7 and the curvature radius R14 of the seventh image-side surface S14 of the seventh lens 7 satisfy R13 / R14=1.463. The seventh lens 7 appropriately diffuses and amplifies the light and corrects the aberration of the light by using the non-rotationally symmetric aspherical surface, so that the image quality formed on the image plane S17 is higher.

[0202] The curvature radius R6 of the third image side surface S6 of the third lens 3 in the y-axis direction perpendicular to the optical axis 11, the curvature radius R10 of the fifth image side surface S10 of the fifth lens in the y-axis direction perpendicular to the optical axis 11, and the effective focal length fy in the Y-axis direction of the imaging lens satisfy: (R6-R10) / fy=-0.630.

[0203] The on-axis distance from the intersection of the seventh object side surface S13 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to the vertex of the effective radius of the seventh object side surface S13 is sag11(x); the on-axis distance from the intersection of the seventh object side surface S13 with the optical axis 11 in the y-axis direction perpendicular to the optical axis 11 to the vertex of the effective radius of the seventh object side surface S13 is sag11(y); sag11(x) is symmetric about the y-axis, and sag11(y) is symmetric about the x-axis, satisfying: sag11(x)=sag11(-x), sag11(y)=sag11(-y). The axial distance from the intersection of the seventh image side surface S14 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to the effective radius vertex of the seventh image side surface S14 is sag12(x); the y-axis distance from the intersection of the seventh image side surface S14 with the optical axis 11 in the axial direction perpendicular to the optical axis 11 to the effective radius vertex of the seventh image side surface S14 is sag12(y); sag12(x) is symmetric about the y-axis, and sag12(y) is symmetric about the x-axis, satisfying: sag12(x)=sag12(-x), sag12(y)=sag12(-y).

[0204] In the optical system of the present embodiment 4, the object plane 8 is a plane, the first object side surface S1 and the first image side surface S2 of the first lens 1, the second object side surface S3 and the second image side surface S4 of the second lens 2, the third object side surface S5 and the third image side surface S6 of the third lens 3, the fourth object side surface S7 and the fourth image side surface S8 of the fourth lens 4, the fifth object side surface S9 and the fifth image side surface S10 of the fifth lens 5, the sixth object side surface S11 and the sixth image side surface S12 of the sixth lens 6 are Q-type aspherical surfaces, the seventh object side surface S13 and the seventh image side surface S14 of the seventh lens 7 are XY polynomial type non-rotationally symmetric aspherical surfaces, the filter 10 has a certain thickness, the filter object side surface S15 and the filter image side surface S16 are both planes, and the image plane S17 is a plane.

[0205] The surface shape of the Q-type aspheric surface can satisfy but is not limited to the following aspheric surface formula:

[0206]

[0207] Among them, z is the aspheric height, r is the radial coordinate of the aspheric surface, c is the vertex spherical curvature of the aspheric surface, K is the quadratic surface constant, and a m is the aspheric coefficient, r max is the maximum radial radius coordinate, u=r / r max .

[0208] The surface shape of the non-rotationally symmetric aspherical surface of the seventh lens 7 is defined by the following aspherical surface formula:

[0209]

[0210] Among them, z is the vector height parallel to the z-axis; N is the total number of polynomial coefficients in the series, Ai is the coefficient of the i-th expanded polynomial, r is the radial coordinate of the aspheric surface, c is the vertex spherical curvature of the aspheric surface, and K is the quadratic surface constant.

[0211] The basic parameters of the optical system of this embodiment 4 are shown in Tables 4a to 4d. Table 4a shows the parameters of each surface, wherein R is the radius of curvature, Th is the surface thickness, nd is the refractive index of the surface material, vd is the Abbe coefficient of the surface material, and f' is the focal length, all of which are in millimeters (mm). Table 4b shows the parameters of each lens, wherein f1 to f7 are the effective focal lengths of each lens, TTL is the total optical length of the optical system, half of the diagonal length of the effective pixel area on the image plane S17 is ImgH, the maximum field of view is FOV, the aperture number of the optical imaging system is Fno, and the effective focal length of the lens group is EFL. Table 4c shows the aspheric parameters of each lens. Table 4d shows the aspheric parameters of a lens having a non-rotationally symmetric aspheric surface.

[0212]

[0213]

[0214] Table 4a

[0215] f1(mm) -18.486 f2(mm) -65.239 f3(mm) 3.923 f4(mm) -9.952 f5(mm) 2.768 f6(mm) -14.754 f7(mm) -11.327 TTL(mm) 6.295 Fno 2.073 ImgH(mm) 5.200 FOV(°) 130 EFL 2.502

[0216] Table 4b

[0217]

[0218]

[0219]

[0220] Table 4c

[0221]

[0222]

[0223] Table 4d

[0224] The basic parameters used in Tables 4a to 4d are used to design the optical system of this embodiment 4, forming Figure 7 The optical system architecture shown in the figure makes full use of the mutual cooperation of the positive and negative transformation of the optical power among the seven lenses, and realizes the ultra-wide-angle and small-distortion ultra-wide-angle lens through the aberration correction and distortion reduction function of the non-rotationally symmetric aspherical surface on the light. Figure 8 As shown in FIG. 1 , the distortion of the image formed by the object on the image plane S17 through the optical system of this embodiment 4 is pincushion distortion, and the distortion is controlled within 2.88%. Figure 8 In the figure, the square solid grid is the ideal image formed under ideal conditions. The image of the object corresponding to the intersection of the solid grid through the optical system of this embodiment 4 is the pixel points suspended around the solid grid. It can be seen that the actual image has a pincushion distortion relative to the solid grid, but the degree of distortion is not large. The pixel points are basically close to the solid grid, which well achieves the purpose of this embodiment 4.

[0225] Example 5

[0226] like Fig. 9As shown, Example 5 of the present application provides an optical system, which has an object plane 8, an image plane S17, an aperture 9, a filter 10 and a lens group consisting of seven lenses. Along the optical axis 11 from the object plane 8 to the image plane S17, a first lens 1, a second lens 2, an aperture 9, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7 and a filter 10 are arranged in sequence. Among them, the ratio of the focal length f1 of the first lens 1 to the effective focal length ft of the lens group is |f1 / ft|=7.508, the ratio of the focal length f2 of the second lens 2 to the effective focal length ft of the lens group is |f2 / ft|=42.385, the ratio of the focal length f3 of the third lens 3 to the effective focal length ft of the lens group is |f3 / ft|=1.486, the ratio of the focal length f4 of the fourth lens 4 to the effective focal length ft of the lens group is |f4 / ft|=3.767, the ratio of the focal length f5 of the fifth lens 5 to the effective focal length ft of the lens group is |f5 / ft|=1.074, the ratio of the focal length f6 of the sixth lens 6 to the effective focal length ft of the lens group is |f6 / ft|=4.738, and the ratio of the focal length f7 of the seventh lens 7 to the effective focal length ft of the lens group is |f7 / ft|=3.769.

[0227] The seventh object-side surface S13 and the seventh image-side surface S14 of the seventh lens 7 are both non-rotationally symmetric aspherical surfaces, and the maximum value TDT of TV distortion within the imaging range of the lens group satisfies |TDT|=1.11%.

[0228] The first lens 1 receives light from the object plane 8 and refracts it to the second lens 2 behind it. The range of light that it can receive is the maximum field of view FOV of the lens group. In this embodiment 5, FOV=110°.

[0229] The effective focal length ft of the lens group has two components in the direction perpendicular to the optical axis 11, namely the effective focal length fx in the x-axis direction and the effective focal length fy in the y-axis direction. The ratio of the entrance pupil diameter EPD of the lens group to fx and fy is the aperture number Fno, and Fno satisfies fx / EPD=2.0, fy / EPD=2.0.

[0230] The distance from the first object-side surface S1 of the first lens 1 of the lens group to the image plane S17 of the lens group on the optical axis 11 is the total optical length TTL, and half of the diagonal length of the effective pixel area on the image plane S17 of the lens group is ImgH, satisfying TTL / ImgH=1.697.

[0231] The curvature radius of the fifth object-side surface S9 of the fifth lens 5 is R9, and the curvature radius of the fifth image-side surface S10 of the fifth lens 5 is R10, satisfying R9 / R10=4.923. The middle thickness of the fifth lens 5 is much greater than the peripheral thickness, thereby enhancing the secondary convergence of light.

[0232] The curvature radius of the sixth object-side surface S11 of the sixth lens 6 is R11, and the curvature radius of the sixth image-side surface S12 of the sixth lens 6 is R12, satisfying R11 / R12=1.591. The sixth lens 6 appropriately diffuses and amplifies the light.

[0233] The curvature radius R13 of the seventh object-side surface S13 of the seventh lens 7 and the curvature radius R14 of the seventh image-side surface S14 of the seventh lens 7 satisfy R13 / R14=1.520. The seventh lens 7 appropriately diffuses and amplifies the light and corrects the aberration of the light by using the non-rotationally symmetric aspherical surface, so that the image quality formed on the image plane S17 is higher.

[0234] The curvature radius R6 of the third image side surface S6 of the third lens 3 in the y-axis direction perpendicular to the optical axis 11, the curvature radius R10 of the fifth image side surface S10 of the fifth lens in the y-axis direction perpendicular to the optical axis 11, and the effective focal length fy in the Y-axis direction of the imaging lens satisfy: (R6-R10) / fy=-0.595.

[0235] The on-axis distance from the intersection of the seventh object side surface S13 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to the vertex of the effective radius of the seventh object side surface S13 is sag11(x); the on-axis distance from the intersection of the seventh object side surface S13 with the optical axis 11 in the y-axis direction perpendicular to the optical axis 11 to the vertex of the effective radius of the seventh object side surface S13 is sag11(y); sag11(x) is symmetric about the y-axis, and sag11(y) is symmetric about the x-axis, satisfying: sag11(x)=sag11(-x), sag11(y)=sag11(-y). The axial distance from the intersection of the seventh image side surface S14 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to the effective radius vertex of the seventh image side surface S14 is sag12(x); the y-axis distance from the intersection of the seventh image side surface S14 with the optical axis 11 in the axial direction perpendicular to the optical axis 11 to the effective radius vertex of the seventh image side surface S14 is sag12(y); sag12(x) is symmetric about the y-axis, and sag12(y) is symmetric about the x-axis, satisfying: sag12(x)=sag12(-x), sag12(y)=sag12(-y).

[0236] In the optical system of the present embodiment 5, the object plane 8 is a plane, the first object-side surface S1 and the first image-side surface S2 of the first lens 1, the second object-side surface S3 and the second image-side surface S4 of the second lens 2, the third object-side surface S5 and the third image-side surface S6 of the third lens 3, the fourth object-side surface S7 and the fourth image-side surface S8 of the fourth lens 4, the fifth object-side surface S9 and the fifth image-side surface S10 of the fifth lens 5, the sixth object-side surface S11 and the sixth image-side surface S12 of the sixth lens 6 are Q-type aspherical surfaces, the seventh object-side surface S13 and the seventh image-side surface S14 of the seventh lens 7 are XY polynomial type non-rotationally symmetric aspherical surfaces, the filter 10 has a certain thickness, the filter object-side surface S15 and the filter image-side surface S16 are both planes, and the image plane S17 is a plane.

[0237] The surface shape of the Q-type aspheric surface can satisfy but is not limited to the following aspheric surface formula:

[0238]

[0239] Among them, z is the aspheric height, r is the radial coordinate of the aspheric surface, c is the vertex spherical curvature of the aspheric surface, K is the quadratic surface constant, and a m is the aspheric coefficient, r max is the maximum radial radius coordinate, u=r / r max .

[0240] The surface shape of the non-rotationally symmetric aspherical surface of the seventh lens 7 is defined by the following aspherical surface formula:

[0241]

[0242] Among them, z is the vector height parallel to the z-axis; N is the total number of polynomial coefficients in the series, Ai is the coefficient of the i-th expanded polynomial, r is the radial coordinate of the aspheric surface, c is the vertex spherical curvature of the aspheric surface, and K is the quadratic surface constant.

[0243] The basic parameters of the optical system of this embodiment 5 are shown in Tables 5a to 5d. Table 5a shows the parameters of each surface, wherein R is the radius of curvature, Th is the surface thickness, nd is the refractive index of the surface material, vd is the Abbe coefficient of the surface material, and f' is the focal length, all of which are in millimeters (mm). Table 5b shows the parameters of each lens, wherein f1 to f7 are the effective focal lengths of each lens, TTL is the total optical length of the optical system, half of the diagonal length of the effective pixel area on the image plane S17 is ImgH, the maximum field of view is FOV, the aperture number of the optical imaging system is Fno, and the effective focal length of the lens group is EFL. Table 5c shows the aspheric parameters of each lens. Table 5d shows the aspheric parameters of a lens having a non-rotationally symmetric aspheric surface.

[0244]

[0245]

[0246] Table 5a

[0247] f1(mm) -27.464 f2(mm) -155.035 f3(mm) 5.436 f4(mm) -13.777 f5(mm) 3.929 f6(mm) -17.332 f7(mm) -13.787 TTL(mm) 8.825 Fno 2.081 ImgH(mm) 5.200 FOV(°) 110 EFL 3.658

[0248] Table 5b

[0249]

[0250]

[0251] Table 5c

[0252]

[0253]

[0254] Table 5d

[0255] The basic parameters used in Table 5a to Table 5d are used to design the optical system of this embodiment 5 to form the following Fig. 9 The optical system architecture shown in the figure makes full use of the mutual cooperation of the positive and negative transformation of the optical power among the seven lenses, and realizes the ultra-wide-angle and small-distortion ultra-wide-angle lens through the aberration correction and distortion reduction function of the non-rotationally symmetric aspherical surface on the light. Fig.10 As shown in FIG. 1 , the distortion of the image formed by the object on the image plane S17 through the optical system of this embodiment 5 is pincushion distortion, and the distortion is controlled within 1.11%. Fig.10 In the figure, the square solid grid is the ideal image formed under ideal conditions. The image of the object corresponding to the intersection of the solid grid through the optical system of this embodiment 5 is the pixel points suspended around the solid grid. It can be seen that the actual image has a pincushion distortion relative to the solid grid, but the degree of distortion is not large. The pixel points are basically close to the solid grid, which well achieves the purpose of this embodiment 5.

[0256] Example 6

[0257] like Fig.11As shown, Example 6 of the present application provides an optical system, which has an object plane 8, an image plane S17, an aperture 9, a filter 10 and a lens group consisting of seven lenses. Along the optical axis 11 from the object plane 8 to the image plane S17, a first lens 1, a second lens 2, an aperture 9, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7 and a filter 10 are arranged in sequence. Among them, the ratio of the focal length f1 of the first lens 1 to the effective focal length ft of the lens group is |f1 / ft|=6.551, the ratio of the focal length f2 of the second lens 2 to the effective focal length ft of the lens group is |f2 / ft|=17.832, the ratio of the focal length f3 of the third lens 3 to the effective focal length ft of the lens group is |f3 / ft|=1.890, the ratio of the focal length f4 of the fourth lens 4 to the effective focal length ft of the lens group is |f4 / ft|=3.886, the ratio of the focal length f5 of the fifth lens 5 to the effective focal length ft of the lens group is |f5 / ft|=1.361, the ratio of the focal length f6 of the sixth lens 6 to the effective focal length ft of the lens group is |f6 / ft|=4.528, and the ratio of the focal length f7 of the seventh lens 7 to the effective focal length ft of the lens group is |f7 / ft|=3.867.

[0258] The seventh object-side surface S13 and the seventh image-side surface S14 of the seventh lens 7 are both non-rotationally symmetric aspherical surfaces, and the maximum value TDT of TV distortion within the imaging range of the lens group satisfies |TDT|=2.91%.

[0259] The first lens 1 receives light from the object plane 8 and refracts it to the second lens 2 behind it. The range of light that it can receive is the maximum field of view FOV of the lens group. In this embodiment 6, FOV=122°.

[0260] The effective focal length ft of the lens group has two components in the direction perpendicular to the optical axis 11, namely the effective focal length fx in the x-axis direction and the effective focal length fy in the y-axis direction. The ratio of the entrance pupil diameter EPD of the lens group to fx and fy is the aperture number Fno, and Fno satisfies fx / EPD=2.0, fy / EPD=2.0.

[0261] The distance from the first object-side surface S1 of the first lens 1 of the lens group to the image plane S17 of the lens group on the optical axis 11 is the total optical length TTL, and half of the diagonal length of the effective pixel area on the image plane S17 of the lens group is ImgH, satisfying TTL / ImgH=1.284.

[0262] The curvature radius of the fifth object-side surface S9 of the fifth lens 5 is R9, and the curvature radius of the fifth image-side surface S10 of the fifth lens 5 is R10, satisfying R9 / R10=5.651. The middle thickness of the fifth lens 5 is much greater than the peripheral thickness, thereby enhancing the secondary convergence of light.

[0263] The curvature radius of the sixth object-side surface S11 of the sixth lens 6 is R11, and the curvature radius of the sixth image-side surface S12 of the sixth lens 6 is R12, satisfying R11 / R12=0.535. The sixth lens 6 appropriately diffuses and amplifies the light.

[0264] The curvature radius R13 of the seventh object-side surface S13 of the seventh lens 7 and the curvature radius R14 of the seventh image-side surface S14 of the seventh lens 7 satisfy R13 / R14=1.635. The seventh lens 7 appropriately diffuses and amplifies the light and corrects the aberration of the light by using the non-rotationally symmetric aspherical surface, so that the image quality formed on the image plane S17 is higher.

[0265] The curvature radius R6 of the third image side surface S6 of the third lens 3 in the y-axis direction perpendicular to the optical axis 11, the curvature radius R10 of the fifth image side surface S10 of the fifth lens in the y-axis direction perpendicular to the optical axis 11, and the effective focal length fy in the Y-axis direction of the imaging lens satisfy: (R6-R10) / fy=-0.704.

[0266] The on-axis distance from the intersection of the seventh object side surface S13 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to the vertex of the effective radius of the seventh object side surface S13 is sag11(x); the on-axis distance from the intersection of the seventh object side surface S13 with the optical axis 11 in the y-axis direction perpendicular to the optical axis 11 to the vertex of the effective radius of the seventh object side surface S13 is sag11(y); sag11(x) is symmetric about the y-axis, and sag11(y) is symmetric about the x-axis, satisfying: sag11(x)=sag11(-x), sag11(y)=sag11(-y). The axial distance from the intersection of the seventh image side surface S14 with the optical axis 11 in the x-axis direction perpendicular to the optical axis 11 to the effective radius vertex of the seventh image side surface S14 is sag12(x); the y-axis distance from the intersection of the seventh image side surface S14 with the optical axis 11 in the axial direction perpendicular to the optical axis 11 to the effective radius vertex of the seventh image side surface S14 is sag12(y); sag12(x) is symmetric about the y-axis, and sag12(y) is symmetric about the x-axis, satisfying: sag12(x)=sag12(-x), sag12(y)=sag12(-y).

[0267] In the optical system of the sixth embodiment, the object plane 8 is a plane, the first object side surface S1 and the first image side surface S2 of the first lens 1, the second object side surface S3 and the second image side surface S4 of the second lens 2, the third object side surface S5 and the third image side surface S6 of the third lens 3, the fourth object side surface S7 and the fourth image side surface S8 of the fourth lens 4, the fifth object side surface S9 and the fifth image side surface S10 of the fifth lens 5, the sixth object side surface S11 and the sixth image side surface S12 of the sixth lens 6 are Q-type aspherical surfaces, the seventh object side surface S13 and the seventh image side surface S14 of the seventh lens 7 are XY polynomial type non-rotationally symmetric aspherical surfaces, the filter 10 has a certain thickness, the filter object side surface S15 and the filter image side surface S16 are both planes, and the image plane S17 is a plane.

[0268] The surface shape of the Q-type aspheric surface can satisfy but is not limited to the following aspheric surface formula:

[0269]

[0270] Among them, z is the aspheric height, r is the radial coordinate of the aspheric surface, c is the vertex spherical curvature of the aspheric surface, K is the quadratic surface constant, and a m is the aspheric coefficient, r max is the maximum radial radius coordinate, u=r / r max .

[0271] The surface shape of the non-rotationally symmetric aspherical surface of the seventh lens 7 is defined by the following aspherical surface formula:

[0272]

[0273] Among them, z is the vector height parallel to the z-axis; N is the total number of polynomial coefficients in the series, Ai is the coefficient of the i-th expanded polynomial, r is the radial coordinate of the aspheric surface, c is the vertex spherical curvature of the aspheric surface, and K is the quadratic surface constant.

[0274] The basic parameters of the optical system of this embodiment 6 are shown in Tables 6a to 6d. Table 6a shows the parameters of each surface, wherein R is the radius of curvature, Th is the surface thickness, nd is the refractive index of the surface material, vd is the Abbe coefficient of the surface material, and f' is the focal length, all of which are in millimeters (mm). Table 6b shows the parameters of each lens, wherein f1 to f7 are the effective focal lengths of each lens, TTL is the total optical length of the optical system, half of the diagonal length of the effective pixel area on the image plane S17 is ImgH, the maximum field of view is FOV, the aperture number of the optical imaging system is Fno, and the effective focal length of the lens group is EFL. Table 6c shows the aspheric parameters of each lens. Table 6d shows the aspheric parameters of a lens having a non-rotationally symmetric aspheric surface.

[0275]

[0276]

[0277] Table 6a

[0278] f1(mm) -16.683 f2(mm) -45.410 f3(mm) 4.813 f4(mm) -9.896 f5(mm) 3.467 f6(mm) 11.532 f7(mm) -9.848 TTL(mm) 6.675 Fno 2.159 ImgH(mm) 5.200 FOV(°) 122 EFL 2.547

[0279] Table 6b

[0280]

[0281]

[0282]

[0283] Table 6c

[0284]

[0285]

[0286] Table 6d

[0287] The basic parameters used in Table 6a to Table 6d are used to design the optical system of this embodiment 6 to form the following Fig.11 The optical system architecture shown in the figure makes full use of the mutual cooperation of the positive and negative transformation of the optical power among the seven lenses, and realizes the ultra-wide-angle and small-distortion ultra-wide-angle lens through the aberration correction and distortion reduction function of the non-rotationally symmetric aspherical surface on the light. Fig.12 As shown in FIG. 1 , the distortion of the image formed by the object on the image plane S17 through the optical system of this embodiment 6 is barrel distortion, and the distortion is controlled within -2.91%. Fig.12 In the figure, the square solid grid is the ideal image formed under ideal conditions. The image of the object corresponding to the intersection of the solid grid through the optical system of this embodiment 6 is the pixel points suspended around the solid grid. It can be seen that the actual image has undergone barrel distortion relative to the solid grid, but the degree of distortion is not large. The pixel points are basically close to the solid grid, which well achieves the purpose of this embodiment 6.

[0288] Example 7

[0289] Embodiment 7 of the present application provides an imaging device, which includes an optical system provided by any one of Embodiments 1 to 6. The imaging device may be a camera module, an infrared camera module, or the like. By providing the optical system in the imaging device, the lens length of the imaging device can be shortened, and the field of view angle can be increased and the distortion can be reduced while ensuring that the imaging size of the image plane S17 remains basically unchanged, thereby realizing an imaging device that combines ultra-wide angle and small distortion.

[0290] Example 8

[0291] Embodiment 8 of the present application provides a terminal device, which includes the imaging device provided in Embodiment 7. By providing the imaging device with the optical system in the terminal device, various shooting application scenarios under different large fields of view can be realized, thereby enhancing the functions of the terminal device and improving the user experience. The terminal device can be a mobile phone, a tablet computer, or other device.

[0292] It can be seen that in all the above aspects, by introducing a non-rotationally symmetric aspheric lens into the optical system, the design freedom is increased, which is beneficial to improving the imaging quality of the lens in a compact system and achieving ultra-wide-angle and small distortion imaging effects. Scenarios such as recording videos and taking photos for preview do not require distortion correction algorithms, and can be used for terminal devices to shoot and record images, such as using lenses of portable electronic products such as mobile phones, tablets, and monitors to shoot external videos and photos, including various shooting application scenarios under different large fields of view.

Claims

1. An optical system, characterized in that: The lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens which are arranged in sequence along the optical axis from the object plane to the image plane; The first lens, the second lens, the fourth lens and the seventh lens have negative optical power; The third lens and the fifth lens have positive refractive power; The sixth lens has optical power; Wherein, at least one of the first lens, the second lens, the fourth lens, the sixth lens and the seventh lens has a non-rotationally symmetric aspherical surface; The third lens has a third image side surface, the curvature radius of the third image side surface in the y-axis direction of the plane perpendicular to the optical axis is R6, the fifth lens has a fifth image side surface, the curvature radius of the fifth image side surface in the y-axis direction of the plane perpendicular to the optical axis is R10, and the effective focal length of the optical system in the y-axis direction of the plane perpendicular to the optical axis is fy, which satisfies the following formula: -0.75<(R6-R10) / fy<-0.5; The total optical length of the optical system is TTL, and half of the length of the diagonal of the imaging area on the image plane is ImgH, which satisfies the following formula: 1.2≤TTL / ImgH≤1.

7.

2. The optical system according to claim 1, wherein: The non-rotationally symmetric aspherical surface is arranged on the seventh lens.

3. The optical system according to claim 1, wherein: The TV distortion of the image formed by the optical system on the image plane is TDT, which satisfies the following formula: |TDT|≤3.0%.

4. The optical system according to claim 1, wherein: The maximum range of the image formed by the optical system on the image plane has a length of Imgx in the x direction and a length of Imgy in the y direction. The half image height of the image is Imgy / Imgx, which satisfies the following formula: Imgy / Imgx=0.

75.

5. The optical system according to claim 1, wherein: The field of view of the optical system is FOV, which satisfies the following formula: 100°≤FOV≤130°.

6. The optical system according to claim 1, wherein: An aperture is arranged between the second lens and the third lens.

7. The optical system according to claim 1, wherein: The fifth lens has a fifth object-side surface and a fifth image-side surface, the fifth object-side surface has a fifth object-side edge away from the optical axis and a fifth object-side center located on the optical axis, the fifth image-side surface has a fifth image-side edge away from the optical axis and a fifth image-side center located on the optical axis, the fifth object-side surface and the fifth image-side surface are respectively curved toward the object plane relative to the fifth object-side center and the fifth image-side center, the fifth object-side center and the fifth image-side center are respectively convex toward the image plane relative to the fifth object-side edge and the fifth image-side edge, a curvature radius R9 of the fifth object-side surface is greater than a curvature radius R10 of the fifth image-side surface, and 4.7≤R9 / R10≤5.7 is satisfied.

8. The optical system according to claim 1, wherein: The sixth lens has a sixth object side surface and a sixth image side surface, the sixth object side surface has a sixth object side edge away from the optical axis and a sixth object side center located on the optical axis, the sixth image side surface has the sixth image side edge away from the optical axis and the sixth image side center located on the optical axis, an area of ​​the sixth object side surface close to the sixth object side edge and an area of ​​the sixth image side surface close to the sixth image side are respectively curved toward the object plane, the sixth object side center and the sixth image side center are both convex toward the object plane, and an effective focal length f6 of the sixth lens and an effective focal length fx of the optical system in the x-axis direction satisfy -6.5≤f6 / fx≤5.

5.

9. The optical system according to claim 1, wherein: The seventh lens has a seventh object side surface and a seventh image side surface, the seventh object side surface has a seventh object side edge away from the optical axis and a seventh object side center located on the optical axis, the seventh image side surface has a seventh image side edge away from the optical axis and a seventh image side center located on the optical axis, an area of ​​the seventh object side surface close to the seventh object side edge and an area of ​​the seventh image side surface close to the seventh image side edge are respectively curved toward the image plane, the seventh object side center and the seventh image side center are both convex toward the object plane, and a curvature radius R13 of the seventh object side surface and a curvature radius R14 of the seventh image side surface satisfy 1.4≤R13 / R14≤1.

7.

10. The optical system according to claim 1, wherein: The effective focal length of the optical system in the x-axis direction of the plane perpendicular to the optical axis is fx, the effective focal length in the y-axis direction of the plane perpendicular to the optical axis is fy, and the entrance pupil diameter is EPD, which satisfies the following formulas: fx / EPD=2.0, fy / EPD=2.

0.

11. The optical system according to claim 1, wherein: The seventh lens has a seventh object-side surface and a seventh image-side surface, and the seventh object-side surface and the seventh image-side surface are respectively centrally symmetric with respect to the optical axis.

12. An imaging device, characterized in that: Comprising the optical system as claimed in any one of claims 1-11.

13. A terminal device, characterized in that: It comprises the imaging device as claimed in claim 12.

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