Optical lens

Abstract

The present invention provides an optical lens, which includes in sequence along the optical axis from the light propagation direction: a first lens with negative optical power, whose object side surface is convex and whose image side surface is concave; a second lens with negative optical power, whose object side surface is convex and whose image side surface is concave; a reflective element, wherein the reflective element includes an incident surface, a reflective surface and an exit surface; a third lens with positive optical power, whose object side surface and image side surface are both convex; a fourth lens with positive optical power, whose object side surface and image side surface are both convex; a fifth lens with positive optical power, whose object side surface and image side surface are both convex; a sixth lens with negative optical power, whose object side surface and image side surface are both concave; a seventh lens with positive optical power, whose object side surface is convex and whose image side surface is concave. The optical lens provided by the present invention can improve the imaging quality of the optical lens, reduce aberrations, and improve the imaging quality of the optical lens.

Description

Technical Field

[0001] The present invention relates to the technical field of imaging lenses, and in particular to an optical lens. Background Art

[0002] As the market environment continues to increase its requirements for panoramic camera lenses, panoramic lenses have been widely used, and the pursuit of the imaging effects of panoramic lenses has become more diversified, requiring both high-definition image quality and a wider viewing angle to record more information. These have made wide-angle high-definition imaging lenses receive more attention.

[0003] Since wide-angle lenses generally have large distortion, the edge imaging effect will be poor, and since the effective focal length of wide-angle lenses is short, the peripheral light entering will have a large compression deformation. Of course, wide-angle lenses have their unique perspective and sense of envelopment, but they appear to be seriously distorted for flat backgrounds. Therefore, how to overcome the distortion of wide-angle lenses is a difficult problem. The development of chips is also moving in two different directions: one is a large-target chip, which has good light transmittance and is very suitable for high-quality image processing needs. Under the same light conditions, it obtains more light information, better image quality, and more information for post-processing. But at the same time, the disadvantage is that the product volume and weight are large; the second is the miniaturization of the chip, which has a lower cost but poor imaging clarity. How to make the wide-angle lens have the advantages of large wide angle and small distortion, and match the imaging chip with a larger target surface to achieve high-definition imaging is a technical problem that technicians in this field need to solve. Summary of the invention

[0004] In view of the above problems, an object of the present invention is to provide an optical lens that at least solves one of the technical problems existing in the prior art.

[0005] The technical solution adopted by the present invention is:

[0006] An optical lens, comprising, in order from the light propagation direction along the optical axis:

[0007] The first lens has a negative optical power, the object side surface of which is convex, and the image side surface of which is concave;

[0008] The second lens has a negative optical power, its object side surface is convex, and its image side surface is concave;

[0009] A reflective element, the reflective element comprising an incident surface, a reflective surface and an exit surface;

[0010] The third lens has positive refractive power, and both the object side surface and the image side surface are convex;

[0011] The fourth lens has positive refractive power, and both the object side surface and the image side surface are convex;

[0012] The fifth lens with a positive optical power, having a convex object side and a convex image side;

[0013] The sixth lens with a negative optical power, having a concave object side and a concave image side;

[0014] The seventh lens with a positive optical power, having a convex object side and a concave image side;

[0015] Wherein, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 21.8 < TTL / f < 22.2; the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: 1.6 < f1 / f2 < 2.2.

[0016] Further preferably, the combined focal length fa of the first lens, the second lens and the third lens and the combined focal length fb of the fourth lens, the fifth lens, the sixth lens and the seventh lens satisfy: 2 < fa / fb < 2.5.

[0017] Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -7.8 < f1 / f < -7; the curvature radius R1 of the object side of the first lens and the curvature radius R2 of the image side of the first lens satisfy: 2.5 < R1 / R2 < 3.

[0018] Further preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -4.3 < f2 / f < -3.8; the curvature radius R3 of the object side of the second lens and the curvature radius R4 of the image side of the second lens satisfy: 2.5 < R3 / R4 < 3.5.

[0019] Further preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 6.5 < f3 / f < 7; the curvature radius R5 of the object side of the third lens and the curvature radius R6 of the image side of the third lens satisfy: -1.8 < R5 / R6 < -0.8.

[0020] Further preferably, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 4.2 < f4 / f < 4.8; the curvature radius R7 of the object side of the fourth lens and the curvature radius R8 of the image side of the fourth lens satisfy: -0.22 < R7 / R8 < -0.12.

[0021] Further preferably, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 5 < f5 / f < 5.5; the curvature radius R9 of the object side of the fifth lens and the curvature radius R10 of the image side of the fifth lens satisfy: -1.3 < R9 / R10 < -0.8.

[0022] More preferably, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -2.8 < f6 / f < -2.4; the object-side curvature radius R11 of the sixth lens and the image-side curvature radius R12 of the sixth lens satisfy: -40 < R11 / R12 < -15.

[0023] More preferably, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 5.1 < f7 / f < 5.5; the object-side curvature radius R13 of the seventh lens and the image-side curvature radius R14 of the seventh lens satisfy: 0 < R13 / R14 < 0.1.

[0024] More preferably, the effective focal length f of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 3.3 < IH / f < 3.5; the total optical length TTL of the optical lens, the true image height IH corresponding to the maximum field of view angle of the optical lens and the maximum field of view angle FOV of the optical lens satisfy: 0.03 / ° < TTL / IH / FOV < 0.035 / °

[0025] More preferably, the distance CT23 along the optical axis direction of the light propagation between the second lens and the third lens and the total optical length TTL of the optical lens satisfy: 0.35 < CT23 / TTL < 0.4.

[0026] More preferably, the reflecting element is a right-angled reflecting prism, and the incident surface and the exit surface are flat surfaces.

[0027] Compared with the prior art, the optical lens provided by the present invention can improve the imaging quality of the optical lens, reduce aberration, and improve the imaging quality of the optical lens by setting a specific surface shape and reasonably distributing the optical power, so that the lens has one or more advantages such as an ultra-large field of view angle, a large image plane, a large aperture, and high imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and / or additional aspects and advantages of the present invention will become apparent and easy to understand from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0029] Figure 1 is a schematic structural diagram of the optical lens in Embodiment 1 of the present invention.

[0030] Figure 2 is an F-(theta) distortion curve graph of the optical lens in Embodiment 1 of the present invention.

[0031] Figure 3 is a vertical chromatic aberration curve graph of the optical lens in Embodiment 1 of the present invention.

[0032] Figure 4This is a relative illumination curve diagram of the optical lens in Example 1 of the present invention.

[0033] Figure 5 This is the MTF curve diagram of the optical lens in Example 1 of the present invention.

[0034] Figure 6 Schematic diagram of the structure of the optical lens in Example 2 of the present invention.

[0035] Figure 7 Graph showing the F-(theta) distortion of the optical lens in Example 2 of the present invention.

[0036] Figure 8 Graph showing the vertical axis chromatic aberration of the optical lens in Example 2 of the present invention.

[0037] Fig. 9 This is a relative illumination curve diagram of the optical lens in Example 2 of the present invention.

[0038] Fig.10 This is an MTF curve diagram of the optical lens in Example 2 of the present invention.

[0039] Fig.11 Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

[0040] Fig.12 Graph showing the F-(theta) distortion of the optical lens in Example 3 of the present invention.

[0041] Fig.13 Graph showing the vertical axis chromatic aberration of the optical lens in Example 3 of the present invention.

[0042] Fig.14 This is a relative illumination curve diagram of the optical lens in Example 3 of the present invention.

[0043] Fig.15 This is the MTF curve diagram of the optical lens in Example 3 of the present invention.

[0044] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0045] In order to better understand the present application, a more detailed description will be made of various aspects of the present application with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of the embodiments of the present application, and are not intended to limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0046] It should be noted that in this specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of the present invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0047] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0048] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is called the object side of the lens, and the surface of each lens closest to the imaging plane is called the image side of the lens.

[0049] It should also be understood that the terms "comprises", "including", "having", "includes" and / or "comprising", when used in this specification, indicate the presence of the stated features, elements and / or components, but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire listed features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application". And, the term "exemplary" is intended to refer to an example or illustration.

[0050] Unless otherwise defined, all terms (including technical terms and scientific terms) used in this article have the same meaning as commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having the same meaning as their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0051] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0052] The optical lens provided by the embodiment of the present invention includes, along the optical axis in the light propagation direction (from the object side to the imaging surface), a first lens, a second lens, a reflection element, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens in sequence, and an air gap is provided between each lens. It can be understood that the surface where light enters each lens is called the object side surface of the lens, and the surface where light exits each lens is called the image side surface of the lens.

[0053] Among them, the first lens may have a negative optical power, its object side surface is convex, and its image side surface is concave. The second lens may have a negative optical power, its object side surface is convex, and its image side surface is concave. The reflection element includes an incident surface, a reflection surface, and an exit surface. The third lens may have a positive optical power, and both its object side surface and image side surface are convex. The fourth lens may have a positive optical power, and both its object side surface and image side surface are convex. The fifth lens may have a positive optical power, and both its object side surface and image side surface are convex. The sixth lens may have a negative optical power, and both its object side surface and image side surface are concave. The seventh lens may have a positive optical power, its object side surface is convex, and its image side surface is concave.

[0054] In some embodiments, the reflection element may adopt a right-angle reflecting prism, and the incident surface and the exit surface may be planes. It can be understood that the incident surface faces the object side, and the exit surface faces the imaging surface. The light from the object side direction enters the prism from the incident surface, is reflected by the reflection surface, and then exits from the exit surface. By setting the right-angle reflecting prism, the optical path direction can be changed, the optical path can be bent, so that the direction of the incident light is perpendicular to the arrangement direction of the multiple lenses, and the overall thickness of the optical system can be reduced.

[0055] In some embodiments, the optical lens may further include a diaphragm, and the diaphragm may be located between the third lens and the fourth lens. It can be understood that the diaphragm is used to limit the amount of incident light to change the brightness of the image. When the diaphragm is located between the third lens and the fourth lens, it is convenient for the correction of diaphragm aberration.

[0056] In some embodiments, the optical lens may further include a filter and a protective glass, and the filter and the protective glass may be sequentially arranged along the optical axis between the seventh lens and the imaging surface. The filter is used to filter out interfering light to prevent the interfering light from reaching the imaging surface of the optical lens and affecting normal imaging. The protective glass plays a role in protecting the optical lens, preventing the photosensitive chip from being damaged, and can improve the anti-impact and scratch-resistant capabilities of the optical lens, while having almost no impact on the imaging quality of the optical lens.

[0057] In some embodiments, the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 21.8 < TTL / f < 22.2. Specifically, TTL refers to the propagation path distance of light from the object side surface of the first lens to the imaging surface. Meeting the above conditions can make the system have a relatively compact structure and better realize the miniaturization of the system.

[0058] In some embodiments, the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: 1.6 < f1 / f2 < 2.2. By satisfying the above conditions, through reasonable setting of the ratio of the focal lengths of the first lens and the second lens, while achieving a large field of view angle, the deflection degree of the incident light within the large field of view can be reasonably balanced, the sensitivity of the optical system can be reduced, the difficulty of distortion correction of the system can be reduced, and the overall imaging quality can be improved.

[0059] In some embodiments, the combined focal length fa of the first lens, the second lens, and the third lens and the combined focal length fb of the fourth lens, the fifth lens, the sixth lens, and the seventh lens satisfy: 2 < fa / fb < 2.5. By satisfying the above conditions, through reasonable setting of the ratio of the focal lengths of the lens groups before and after the aperture, it is beneficial to reduce the spherical aberration and field curvature generated by the front lens group of the optical lens, and at the same time enable the rear lens group to better balance the distortion and astigmatism generated by the front lens group, improving the imaging quality of the optical lens.

[0060] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -7.8 < f1 / f < -7; the curvature radius R1 of the object side surface of the first lens and the curvature radius R2 of the image side surface of the first lens satisfy: 2.5 < R1 / R2 < 3. By satisfying the above conditions, the first lens can have an appropriate negative optical power and surface shape, which can slow down the deflection degree of the incident light, help more light enter the optical system within a larger range, is beneficial to expanding the field of view angle of the lens, and at the same time is beneficial to reducing the system aberration, realizing the development of the lens towards ultra-thinness and wide-angle.

[0061] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -4.3 < f2 / f < -3.8; the curvature radius R3 of the object side surface of the second lens and the curvature radius R4 of the image side surface of the second lens satisfy: 2.5 < R3 / R4 < 3.5. By satisfying the above conditions, through reasonable setting of the optical power and surface shape of the second lens, the incident light can be further diverged, which is beneficial to improving the field of view angle of the system, reducing the difficulty of distortion correction of the edge field of view while increasing the field of view angle, making the lens have less distortion, and improving the overall imaging quality.

[0062] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 6.5 < f3 / f < 7; the curvature radius R5 of the object side surface of the third lens and the curvature radius R6 of the image side surface of the third lens satisfy: -1.8 < R5 / R6 < -0.8. By satisfying the above conditions, the third lens can bear a reasonable positive optical power, can converge the light rays emitted from the reflection element to the greatest extent, effectively reduce the field curvature and distortion of the system, and improve the imaging quality.

[0063] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 4.2 < f4 / f < 4.8; the curvature radius R7 of the object side surface of the fourth lens and the curvature radius R8 of the image side surface of the fourth lens satisfy: -0.22 < R7 / R8 < -0.12. Meeting the above conditions is conducive to further convergence of light rays, enabling the divergent light rays to smoothly enter the rear optical system and better achieving high-quality imaging of the lens.

[0064] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 5 < f5 / f < 5.5; the curvature radius R9 of the object side surface of the fifth lens and the curvature radius R10 of the image side surface of the fifth lens satisfy: -1.3 < R9 / R10 < -0.8. Meeting the above conditions can effectively improve the aberration of the edge field of view and enhance the overall imaging quality of the optical lens.

[0065] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -2.8 < f6 / f < -2.4; the curvature radius R11 of the object side surface of the sixth lens and the curvature radius R12 of the image side surface of the sixth lens satisfy: -40 < R11 / R12 < -15. Meeting the above conditions, by setting the sixth lens to have a large negative refractive power, it is conducive to balancing various aberrations generated by the front lens group and improving the overall imaging quality.

[0066] In some embodiments, the effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 5.1 < f7 / f < 5.5; the curvature radius R13 of the object side surface of the seventh lens and the curvature radius R14 of the image side surface of the seventh lens satisfy: 0 < R13 / R14 < 0.1. Meeting the above conditions is conducive to increasing the area of light entering the imaging surface, achieving large target surface imaging of the lens, and enhancing the imaging quality of the optical lens.

[0067] In some embodiments, the effective focal length f of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 3.3 < IH / f < 3.5; the overall optical length TTL of the optical lens, the true image height IH corresponding to the maximum field of view angle of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 0.03 / ° < TTL / IH / FOV < 0.035 / °. Meeting the above conditions, while ensuring that the lens has a large field of view angle, it has a larger imaging surface and a smaller overall length, and better achieves ultra-wide angle, miniaturization, and high-pixel imaging of the lens.

[0068] In some embodiments, the distance CT23 along the optical axis for light propagation between the second lens and the third lens and the total optical length TTL of the optical lens satisfy: 0.35 < CT23 / TTL < 0.4. By satisfying the above conditions, by providing a relatively large air gap between the second and third lenses, while satisfying the deflection of incident light, a relatively large placement space is reserved for the reflective element, interference between different components is reduced, and the imaging yield is improved.

[0069] In some embodiments, the effective focal length f of the optical lens, the maximum field of view FOV of the optical lens, and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 56° < (f × FOV) / IH < 60°. By satisfying the above conditions, by reasonably restricting the relationship between the focal length, field of view angle, and image height of the optical lens, it is beneficial to achieve the balance of miniaturization, large field of view angle, and large target surface imaging of the optical lens.

[0070] In some embodiments, the focal length f3 of the third lens and the focal length f4 of the fourth lens satisfy: 1.3 < f3 / f4 < 1.7; the focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy: -2.2 < f5 / f6 < -1.9. By satisfying the above conditions, by reasonably distributing the focal length relationship of the lenses after the reflective element, it is possible to avoid excessive deflection of light when passing through the system, reduce the difficulty of aberration correction, and at the same time be able to better correct the field curvature and distortion of the lens, ensuring that the field curvature and distortion of the lens are controlled at a relatively small level, and achieving high-pixel imaging of the system.

[0071] In some embodiments, the focal length f1 of the first lens and the focal length f7 of the seventh lens satisfy: -1.5 < f1 / f7 < -1.1. By satisfying the above conditions, by reasonably setting the focal length relationship of the first and last lenses in the lens, while ensuring that as much light as possible enters the system, the area of light entering the imaging surface is increased, which is beneficial to achieving large image surface imaging of the lens, while also increasing the light input and improving the relative illuminance of the system.

[0072] In some embodiments, the combined focal length fa of the first lens, the second lens, and the third lens and the effective focal length f of the optical lens satisfy: 8 < fa / f < 10. By satisfying the above conditions, it is beneficial for large-angle light to enter the system to achieve a large field of view angle of the system, and it is also beneficial to increase the light flux of the system, better achieve a large aperture of the lens, and improve the relative illuminance of the system.

[0073] In some embodiments, the combined focal length fb of the fourth lens, the fifth lens, the sixth lens, and the seventh lens and the effective focal length f of the optical lens satisfy: 4 < fb / f < 4.5. By satisfying the above conditions, it is beneficial to balance the distortion and astigmatism generated by the front-end lens of the optical lens and improve the imaging quality of the optical lens.

[0074] In some embodiments, the optical lens satisfies the following conditional expressions: f < 2 mm; 190° < FOV < 210°; 35 mm < TTL < 36 mm; 5 mm < IH < 6 mm; Fno < 2.1. In the above conditional expressions, f represents the effective focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, TTL represents the total optical length of the optical lens (i.e., the propagation path distance of light from the object side of the first lens to the imaging surface), IH represents the true image height corresponding to the maximum field of view angle of the optical lens, and Fno represents the aperture value of the optical lens. Meeting the above ranges, the optical lens has at least one or more advantages such as an ultra-large field of view angle, a large image plane, and a large aperture.

[0075] In some embodiments, the lens material in the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. On the other hand, when the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected by the low dispersion characteristic of the glass itself. The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens provided by the present invention can all adopt glass lenses.

[0076] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens can adopt spherical lenses or aspherical lenses. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens. More specifically, the first lens, the third lens, the fourth lens, and the sixth lens of the present invention all adopt spherical lenses, and the second lens, the fifth lens, and the seventh lens all adopt aspherical lenses.

[0077] In various embodiments of the present invention, when the lens adopts an aspherical lens, the shapes of the aspherical surfaces of the optical lens satisfy the following equations:

[0078] ;

[0079] where z is the distance between the surface and the vertex of the surface in the optical axis direction, h is the distance from the optical axis to the surface, c is the curvature of the vertex of the surface, K is the conic coefficient, and B, C, D, and E are the fourth-order, sixth-order, eighth-order, and tenth-order surface coefficients, respectively.

[0080] The present invention is further described below in multiple embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens are different. For specific differences, please refer to the parameter table of each embodiment. The following embodiments are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following embodiments. Any other changes, substitutions, combinations or simplifications that do not deviate from the innovative points of the present invention should be regarded as equivalent replacement methods and are included in the protection scope of the present invention.

[0081] Example 1

[0082] See also Figure 1 , which is a schematic diagram of the structure of the optical lens 100 provided in Embodiment 1 of the present invention. The optical lens 100 includes, in order from the light propagation direction (from the object side to the imaging surface) along the optical axis: a first lens L1, a second lens L2, a right-angle reflection prism 10, a third lens L3, an aperture ST, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, a filter G1 and a protective glass G2. It can be understood that the surface of each lens where the light enters is called the object side surface of the lens, and the surface where the light exits is called the image side surface of the lens.

[0083] The first lens L1 has negative refractive power, its object side surface S1 is convex, and its image side surface S2 is concave;

[0084] The second lens L2 has negative refractive power, its object-side surface S3 is convex, and its image-side surface S4 is concave;

[0085] The right-angle reflecting prism 10 includes an incident surface S5, a reflecting surface R0 and an exiting surface S6; the incident surface S5 and the exiting surface S6 can be planes. It can be understood that the incident surface S5 faces the object side, and the exiting surface S6 faces the imaging surface.

[0086] The third lens L3 has positive refractive power, and its object-side surface S7 and image-side surface S8 are both convex;

[0087] The fourth lens L4 has positive refractive power, and its object-side surface S9 and image-side surface S10 are both convex surfaces;

[0088] The fifth lens L5 has positive refractive power, and its object-side surface S11 and image-side surface S12 are both convex surfaces;

[0089] The sixth lens L6 has negative refractive power, and its object-side surface S13 and image-side surface S14 are both concave surfaces;

[0090] The seventh lens L7 has positive refractive power, its object-side surface S15 is convex, and its image-side surface S16 is concave;

[0091] The object side surface S17 and the image side surface S18 of the filter G1 are both planes;

[0092] The object-side surface S19 and the image-side surface S20 of the protective glass G2 are both flat surfaces.

[0093] The first lens L1, the third lens L3, the fourth lens L4, and the sixth lens L6 are all glass spherical lenses, and the second lens L2, the fifth lens L5, and the seventh lens L7 are all glass aspherical lenses.

[0094] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0095] Table 1-1

[0096]

[0097] The surface parameters of the aspheric lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0098] Table 1-2

[0099]

[0100] In this embodiment, the F-(theta) distortion curve, the vertical axis chromatic aberration curve, the relative illumination curve, and the MTF curve of the optical lens 100 are respectively as shown in FIG. Figure 2 , Figure 3 , Figure 4 , Figure 5 shown.

[0101] Figure 2 The F-(theta) distortion curve of Example 1 is shown, which represents the distortion of light of different wavelengths at different image heights on the imaging surface, with the horizontal axis representing the distortion value (unit: %) and the vertical axis representing the half field angle (unit: °). It can be seen from the figure that the distortion of the optical lens is controlled within ±2%, indicating that the optical lens can correct the distortion well.

[0102] Figure 3 The vertical chromatic aberration curve of Example 1 is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.546 μm) at different image heights on the imaging surface, the horizontal axis represents the vertical chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field angle. It can be seen from the figure that the vertical chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2 μm, indicating that the optical lens can correct chromatic aberration well.

[0103] Figure 4The relative illumination curve of Example 1 is shown, which represents the relative illumination values ​​at different viewing angles on the imaging plane, with the horizontal axis representing the half viewing angle (unit: °) and the vertical axis representing the relative illumination (unit: %). It can be seen from the figure that the relative illumination value of the optical lens is still greater than 0.7 at the maximum half viewing angle, indicating that the optical lens has good relative illumination.

[0104] Figure 5 The MTF (Modulation Transfer Function) curve of Example 1 is shown, which represents the imaging modulation degree of the lens at different spatial frequencies under each field of view, the horizontal axis represents the spatial frequency (unit: cycle / mm), and the vertical axis represents the MTF value. It can be seen from the figure that the MTF value of this embodiment is above 0.5 in the entire field of view, and in the range of 0 to 200 cycles / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency conditions.

[0105] Example 2

[0106] See also Figure 6 , shown is a schematic diagram of the structure of the optical lens 200 provided in Example 2 of the present invention. Compared with Example 1, the main difference between this embodiment and Example 1 is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0107] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0108] Table 2-1

[0109]

[0110] The surface parameters of the aspheric lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0111] Table 2-2

[0112]

[0113] In this embodiment, the F-(theta) distortion curve, the vertical axis chromatic aberration curve, the relative illumination curve, and the MTF curve of the optical lens 200 are shown as follows: Figure 7 , Figure 8 , Fig. 9 , Fig.10 shown.

[0114] from Figure 7 It can be seen that the distortion of the optical lens is controlled within ±2%, which means that the optical lens can correct the distortion well.

[0115] from Figure 8It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2.5μm, indicating that the optical lens can correct chromatic aberration well.

[0116] from Fig. 9 It can be seen that at the maximum half field of view angle, the relative illumination value of the optical lens is still greater than 0.7, indicating that the optical lens has good relative illumination.

[0117] from Fig.10 It can be seen that the MTF value of this embodiment is above 0.5 in the whole field of view. In the range of 0 to 200 cycles / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution capability in both low-frequency and high-frequency conditions.

[0118] Example 3

[0119] See also Fig.11 , shown is a schematic diagram of the structure of the optical lens 300 provided in Example 3 of the present invention. Compared with Example 1, the main difference between this embodiment and Example 1 is that the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0120] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0121] Table 3-1

[0122]

[0123] The surface parameters of the aspheric lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0124] Table 3-2

[0125]

[0126] In this embodiment, the F-(theta) distortion curve, the vertical axis chromatic aberration curve, the relative illumination curve, and the MTF curve of the optical lens 300 are shown as follows: Fig.12 , Fig.13 , Fig.14 , Fig.15 shown.

[0127] from Fig.12 It can be seen that the distortion of the optical lens is controlled within ±2%, which means that the optical lens can correct the distortion well.

[0128] from Fig.13 It can be seen that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2.5μm, indicating that the optical lens can correct chromatic aberration well.

[0129] from Fig.14 It can be seen that at the maximum half field of view angle, the relative illumination value of the optical lens is still greater than 0.7, indicating that the optical lens has good relative illumination.

[0130] from Fig.15 It can be seen that the MTF value of this embodiment is above 0.5 in the whole field of view. In the range of 0 to 200 cycles / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, and has good imaging quality and good detail resolution capability in both low-frequency and high-frequency conditions.

[0131] Please refer to Table 4, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f of the optical lens, the total optical length TTL, the aperture value Fno, the main ray incidence angle CRA at the maximum image height, the real image height IH corresponding to the maximum field of view angle, the maximum field of view angle FOV, and the numerical value corresponding to each conditional expression in each embodiment.

[0132] Table 4

[0133]

[0134] In summary, the optical lens provided by the present invention has at least the following advantages:

[0135] (1) Through the combination of specific surface shapes and reasonable optical focal length distribution, it has an ultra-large field of view (FOV can reach 200°), expands the field of view and has small distortion; it can realize the large image plane characteristics of the lens, can carry a larger chip, and realize high-definition imaging of the lens. At the same time, the present invention also has a large aperture performance, high relative illumination, and can achieve high-definition imaging even in a dim environment, which can improve the imaging quality of the optical lens, reduce aberrations, and improve the imaging quality of the optical lens.

[0136] (2) The design of a folding prism is used to bend the optical path and reduce the overall thickness of the optical system.

[0137] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0138] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An optical lens, characterized in that: In the light propagation direction along the optical axis, it successively includes: A first lens with negative optical power, its object side is convex, and its image side is concave; A second lens with negative optical power, its object side is convex, and its image side is concave; A reflecting element, which includes an incident surface, a reflecting surface, and an exit surface; A third lens with positive optical power, its object side and image side are both convex; A fourth lens with positive optical power, its object side and image side are both convex; A fifth lens with positive optical power, its object side and image side are both convex; A sixth lens with negative optical power, its object side and image side are both concave; A seventh lens with positive optical power, its object side is convex, and its image side is concave; Wherein, the number of lenses with optical power in the optical lens is seven; the total optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 21.8 < TTL / f < 22.2; the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: 1.6 < f1 / f2 < 2.2; the combined focal length fa of the first lens, the second lens, and the third lens and the combined focal length fb of the fourth lens, the fifth lens, the sixth lens, and the seventh lens satisfy: 2 < fa / fb < 2.

5.

2. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -7.8 < f1 / f < -7; the curvature radius R1 of the object side of the first lens and the curvature radius R2 of the image side of the first lens satisfy: 2.5 < R1 / R2 < 3.

3. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -4.3 < f2 / f < -3.8; the curvature radius R3 of the object side of the second lens and the curvature radius R4 of the image side of the second lens satisfy: 2.5 < R3 / R4 < 3.

5.

4. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 6.5 < f3 / f < 7; the curvature radius R5 of the object side of the third lens and the curvature radius R6 of the image side of the third lens satisfy: -1.8 < R5 / R6 < -0.

8.

5. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 4.2 < f4 / f < 4.8; the curvature radius R7 of the object side of the fourth lens and the curvature radius R8 of the image side of the fourth lens satisfy: -0.22 < R7 / R8 < -0.

12.

6. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 5 < f5 / f < 5.5; the curvature radius R9 of the object side of the fifth lens and the curvature radius R10 of the image side of the fifth lens satisfy: -1.3 < R9 / R10 < -0.

8.

7. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -2.8 < f6 / f < -2.4; the curvature radius R11 of the object side of the sixth lens and the curvature radius R12 of the image side of the sixth lens satisfy: -40 < R11 / R12 < -15.

8. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f7 of the seventh lens satisfy: 5.1 < f7 / f < 5.5; the radius of curvature R13 of the object side surface of the seventh lens and the radius of curvature R14 of the image side surface of the seventh lens satisfy: 0 < R13 / R14 < 0.

1.

9. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 3.3 < IH / f < 3.5; the total optical length TTL of the optical lens, the true image height IH corresponding to the maximum field of view angle of the optical lens, and the maximum field of view angle FOV of the optical lens satisfy: 0.03 / ° < TTL / IH / FOV < 0.035 / °.

10. The optical lens according to claim 1, characterized in that: The distance CT23 along the optical axis direction of light propagation between the second lens and the third lens and the total optical length TTL of the optical lens satisfy: 0.35 < CT23 / TTL < 0.

4.

11. The optical lens according to claim 1, characterized in that: The reflecting element uses a right-angle reflecting prism, and the incident surface and the exit surface are flat surfaces.

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