Optical lens

Abstract

The present invention provides an optical lens, which sequentially includes, from the object side to the imaging surface: a first reflecting element with positive optical power and a second group with negative optical power; the image side surface of the first reflecting element is convex, and a reflecting surface is provided between the object side surface and the image side surface of the first reflecting element; the second group sequentially includes, along the optical axis from the object side to the imaging surface: a second lens with negative optical power, a third lens with optical power, and a fourth lens with optical power; the object side surface of the third lens is concave; the object side surface of the fourth lens is convex; the focal length f1 of the first reflecting element and the combined focal length f of the second group Q2 Satisfy: -0.6 < f1 / f Q2 < 0. The optical lens of the present invention adopts the combination of a reflecting element with diopter and multiple lenses, which can reduce the number of lenses, reduce costs, effectively compress the optical aperture of the lenses, and has the characteristics of miniaturization and thinness.

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] In order to pursue a longer and better photography experience on mobile devices, periscope lenses that use prisms and other refractive elements to turn the light path began to appear and gradually became standard lenses in imaging modules. However, due to the thickness of the mobile device itself, the aperture of the periscope lens cannot be increased, which hinders the development of periscope lenses with large apertures, large image surfaces, and large light throughput. In addition, conventional prisms only play a turning role in the light path. The compression imaging of large-aperture and large-field-of-view light can only depend on subsequent lenses with refractive power, and the aperture of these lenses is limited by the thickness of the module. Therefore, the periscope lens cannot have a large light throughput and high-performance imaging effect. Summary of the invention

[0003] In view of the above problems, an object of the present invention is to provide an optical lens having the advantage of excellent imaging quality.

[0004] The technical solution adopted by the present invention is:

[0005] An optical lens, comprising, from the object side to the imaging surface, a first reflecting element with positive optical power and a second reflecting element with negative optical power;

[0006] The object side surface of the first reflective element is a concave surface or a convex surface, the image side surface of the first reflective element is a convex surface, and a reflective surface is provided between the object side surface and the image side surface of the first reflective element; the reflective surface of the first reflective element forms an angle of 30° to 60° with the optical axes of the object side surface and the image side surface of the first reflective element; the first reflective element adopts an integrally formed structure;

[0007] The second group includes, in order from the object side to the imaging plane along the optical axis: a second lens having negative optical power, a third lens having optical power, and a fourth lens having optical power;

[0008] The object side surface of the third lens is a concave surface;

[0009] The object side surface of the fourth lens is a convex surface;

[0010] The focal length f1 of the first reflective element and the combined focal length f Q2 Satisfied: -0.6 <f1 / f Q2 <0.

[0011] Further preferably, both the object side surface and the image side surface of the first reflective element are aspherical surfaces; the reflective surface of the first reflective element forms an angle of 45° with the optical axes of the object side surface and the image side surface of the first reflective element.

[0012] Further preferably, the object side, the image side and the reflection surface of the first reflection element are all rectangular, and the clear aperture DM1 in the wide side direction of the first reflection element satisfies: DM1 < 4.5 mm; the clear aperture DM1 in the wide side direction of the first reflection element and the clear aperture DL1 in the long side direction of the first reflection element satisfy: 0.7 < DM1 / DL1 < 1.

[0013] Further 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: 0.7 < IH / f < 0.8.

[0014] Further preferably, the total length TTL on the optical axis from the object side of the first reflection element to the imaging surface and the effective focal length f of the optical lens satisfy: 1.5 < TTL / f < 2; the total length TTL on the optical axis from the object side of the first reflection element to the imaging surface and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 2 < TTL / IH < 2.8.

[0015] Further preferably, the effective focal length f of the optical lens and the combined focal length f Q2 of the second group satisfy: -25 < f Q2 / f < -1.

[0016] Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first reflection element satisfy: 0.3 < f1 / f < 1; the effective focal length of the optical lens and the radius of curvature R2 of the image side of the first reflection element satisfy: -1 < R2 / f < -0.2.

[0017] Further preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -3 < f2 / f < -0.3; the radius of curvature R3 of the object side of the second lens and the radius of curvature R4 of the image side of the second lens satisfy: 0.1 < R3 / R4 < 2.

[0018] Further preferably, the effective focal length f of the optical lens and the radius of curvature R5 of the object side of the third lens satisfy: -0.5 < R5 / f < -0.2; the effective focal length f of the optical lens and the radius of curvature R7 of the object side of the fourth lens satisfy: R7 / f > 0.1.

[0019] Further preferably, the propagation length CT1 of the light on the optical axis of the first reflection element and the sum CT of the central thicknesses of the lenses in the second group on the optical axis Q2 satisfy: 2.5 < CT1 / CT Q2 < 4.

[0020] Further preferably, the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.6 < BFL / f < 0.9; the back focal length BFL of the optical lens and the total length TTL on the optical axis from the object side of the first reflecting element to the imaging surface satisfy: 0.38 < BFL / TTL < 0.48.

[0021] The optical lens of the present invention adopts a combination of a reflecting element and a lens. The diopter of the reflecting element itself has a good balancing effect on the aberration in the optical system. After the light with a large far-field and large aperture is effectively compressed by the reflecting element and then enters the subsequent lens, the number of subsequent lenses can be reduced and the cost can be lowered. In addition, while increasing the light input and improving the optical performance of the system, the optical aperture of the lens is effectively compressed, thereby solving the problem of the aperture limitation of the subsequent lens under the aperture and having the characteristics of miniaturization and thinning. Description of the Drawings

[0022] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, where:

[0023] Figure 1 It is a schematic structural diagram of the optical lens in Embodiment 1 of the present invention.

[0024] Figure 2 It is a chromatic aberration magnification curve diagram of the optical lens in Embodiment 1 of the present invention.

[0025] Figure 3 It is a distortion curve diagram of the optical lens in Embodiment 1 of the present invention.

[0026] Figure 4 It is an axial aberration curve diagram of the optical lens in Embodiment 1 of the present invention.

[0027] Figure 5 It is a schematic structural diagram of the optical lens in Embodiment 2 of the present invention.

[0028] Figure 6 It is a chromatic aberration magnification curve diagram of the optical lens in Embodiment 2 of the present invention.

[0029] Figure 7 It is a distortion curve diagram of the optical lens in Embodiment 2 of the present invention.

[0030] Figure 8 It is an axial aberration curve diagram of the optical lens in Embodiment 2 of the present invention.

[0031] Fig. 9 It is a schematic structural diagram of the optical lens in Embodiment 3 of the present invention.

[0032] Fig.10 It is a chromatic aberration magnification curve diagram of the optical lens in Embodiment 3 of the present invention.

[0033] Fig.11 3 is a distortion curve diagram of the optical lens in Example 3 of the present invention.

[0034] Fig.12 Graph showing the axial aberration of the optical lens in Embodiment 3 of the present invention.

[0035] Fig.13 Schematic diagram of the structure of the optical lens in Example 4 of the present invention.

[0036] Fig.14 4 is a graph showing the magnification chromatic aberration of the optical lens in Example 4 of the present invention.

[0037] Fig.15 This is a distortion curve diagram of the optical lens in Example 4 of the present invention.

[0038] Fig.16 4 is an axial aberration curve diagram of the optical lens in Example 4 of the present invention.

[0039] Fig.17 Schematic diagram of the structure of the optical lens in Example 5 of the present invention.

[0040] Fig.18 Graph showing the magnification chromatic aberration of the optical lens in Embodiment 5 of the present invention.

[0041] Fig.19 This is a distortion curve diagram of the optical lens in Example 5 of the present invention.

[0042] Fig. 20 Graph showing the axial aberration of the optical lens in Embodiment 5 of the present invention.

[0043] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] The optical lens provided by the embodiment of the present invention includes, from the object side to the imaging surface, a first reflective element with positive optical power and a second group with negative optical power. The first reflective element of the present invention is used to deflect light, and by changing the angle of the incident light, the direction of the incident light is perpendicular to the arrangement direction of the second group, thereby reducing the overall thickness of the optical system and achieving the effect of a periscope-type long focal length lens.

[0052] In some embodiments, the object side surface of the first reflective element is a concave surface or a convex surface, and the image side surface of the first reflective element is a convex surface. The light incident surface of the first reflective element is the object side surface, and the light exiting surface of the first reflective element is the image side surface. A reflective surface is provided between the object side surface and the image side surface of the first reflective element. The light enters the system through the object side surface (light incident surface) of the first reflective element, and after being reflected by the reflective surface, it is emitted from the image side surface (light exiting surface) of the first reflective element and enters the subsequent second group. The second group includes, from the object side to the imaging surface along the optical axis, a second lens with negative optical power, a third lens with optical power, and a fourth lens with optical power. The third lens may have negative optical power or positive optical power, and the fourth lens may have negative optical power or positive optical power. Among them, the object side surface of the second lens may be a concave surface or a convex surface, and the image side surface of the second lens may be a concave surface or a convex surface. The object side surface of the third lens is a concave surface, and the image side surface of the third lens may be a concave surface or a convex surface. The object-side surface of the fourth lens is a convex surface, and the image-side surface of the fourth lens can be a concave surface or a convex surface.

[0053] In some embodiments, the reflection surface of the first reflection element forms an angle of 30° to 60° with the optical axes of the object side and image side of the first reflection element; the first reflection element adopts an integrally formed structure. In some embodiments, the first reflection element may adopt a prism structure for turning the light. Specifically, it may be an isosceles right-angle prism, and the reflection surface of the prism forms an angle of 45° with the optical axes of the object side and image side of the prism. The object side and image side of the prism may both be aspherical surfaces, and the reflection surface may be a plane. It is understandable that its object side faces the object side, and its image side faces the imaging surface. Light from the object side direction enters the prism from the object side, is reflected by the reflection surface, and then is emitted from the image side. The setting of the folding prism can change the direction of the light path, bend the light path, so that the direction of the incident light is perpendicular to the arrangement direction of the multiple lenses, and reduce the overall thickness of the optical system; at the same time, the angle of the incident light can be converged, which is conducive to achieving the effect of periscope telephoto lens.

[0054] In some embodiments, the optical lens may further include an aperture, and the aperture may be located between the first reflective element and the second lens. It is understood that the aperture is used to limit the amount of incoming light to change the brightness of the image.

[0055] In some embodiments, the optical lens may further include a filter, which may be disposed between the fourth lens and the imaging surface. The filter is used to filter out interference light to prevent the interference light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0056] In some embodiments, the focal length f1 of the first reflective element and the combined focal length f Q2 Satisfied: -0.6 <f1 / f Q2 <0; More specifically, the focal length f1 of the first reflective element and the combined focal length fQ2 Satisfy: -0.5 < f1 / f Q2 <-0.03. In the present application, the first reflecting element is an aspherical prism, and both the object side and the image side of the prism are aspherical. Since the prism itself has a relatively large positive diopter, light with a large far-field, large aperture is effectively compressed by the aspherical prism and then enters the subsequent lenses of the second group. The light rays are expanded to a certain extent in the second group, causing the peripheral light rays and the central light rays to turn upwards, reaching a higher imaging position, better realizing large target surface imaging of the lens, and improving the imaging quality. Meeting the above conditions, while increasing the light input and improving the optical performance of the system, the optical aperture of the lenses in the second group is effectively compressed, thus solving the problem of the aperture limitation of the subsequent lenses under a large aperture, making the overall lens have the characteristics of miniaturization, large aperture, and large image surface, and being able to better meet the design requirements of periscope telephoto lenses.

[0057] In some embodiments, the object side, the image side, and the reflecting surface of the first reflecting element in the present application are all rectangular. It can be understood that since the reflecting surface of the prism forms a 45° angle with the optical axes of the object side and the image side of the prism, the width of the rectangle is equivalent to the thickness direction of the optical system.

[0058] In some embodiments, the clear aperture semi-diameter DM1 in the width direction of the first reflecting element satisfies: DM1 < 4.5 mm; the clear aperture semi-diameter DM1 in the width direction of the first reflecting element and the clear aperture semi-diameter DL1 in the long side direction of the first reflecting element satisfy: 0.7 < DM1 / DL1 < 1. In the present application, the first reflecting element adopts an aspherical prism design, and the reflecting surface of the prism forms a 45° angle with the optical axes of the object side (light incident surface) and the image side (light exit surface) of the prism. The prism changes the angle of the incident light rays, enabling the lens to be installed in the electronic device in a horizontal manner; since the object side (light incident surface), the reflecting surface, and the image side (light exit surface) of the prism are all rectangular, therefore, to horizontally place the periscope lens in the electronic device, the width direction of the prism needs to be controlled within a certain range (such as not greater than the thickness of the electronic device), while the long side direction is not restricted; more specifically, meeting the above conditions, a larger clear aperture can be set in the long side direction of the prism, increasing the light flux of the system to a large extent, and ensuring that the rear end of the lens can be horizontally placed in the electronic device, being able to well realize the requirement of thinning of periscope electronic devices.

[0059] 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: 0.7 < IH / f < 0.8. Meeting the above conditions can make the lens have a longer focal length and a larger imaging surface.

[0060] In some embodiments, the total length TTL on the optical axis from the object side of the first reflecting element to the imaging surface and the effective focal length f of the optical lens satisfy: 1.5 < TTL / f < 2; the total length TTL on the optical axis from the object side of the first reflecting element to the imaging surface and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 2 < TTL / IH < 2.8. It can be understood that TTL refers to the propagation path length of light from the object side of the first reflecting element to the imaging surface along the optical axis. Meeting the above conditions can make the lens have a longer focal length and a larger imaging surface.

[0061] In some embodiments, the effective focal length f of the optical lens and the combined focal length f of the second group Q2 satisfy: -25 < f Q2 / f < -1. Meeting the above conditions can effectively expand the light beam refracted from the first reflecting element, shorten the total length of the lens and the lens aperture of the second group while ensuring the long focal length performance of the lens, and can effectively reduce the height of the periscope telephoto module, meeting the requirements of the thinness development of terminal devices.

[0062] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first reflecting element satisfy: 0.3 < f1 / f < 1. Meeting the above conditions, the first reflecting element uses an aspherical prism with refractive power to replace the ordinary prism in the periscope telephoto lens, and the first reflecting element is set to have a large positive refractive power. After effectively compressing the light with a large field of view and large aperture from afar by the first reflecting element, it enters the subsequent second group at a relatively gentle angle, which can greatly reduce the size of the light passing aperture and the number of lenses of the subsequent lenses, and better achieve the long focal length performance and large light passing aperture of the lens.

[0063] In some embodiments, the effective focal length of the optical lens and the radius of curvature R2 of the image side of the first reflecting element satisfy: -1 < R2 / f < -0.2. Meeting the above conditions, the first reflecting element uses an aspherical prism design. By reasonably controlling the size of the radius of curvature of the image side of the first reflecting element, the aspherical surface type of the prism is easy to process, providing greater possibility for the injection molding integration of the aspherical prism. At the same time, it can effectively converge the exit angle of the light, reduce the size of the light passing aperture of the second group in the thickness direction of the electronic device (such as a mobile phone), and can better achieve the balance of the large aperture and the small rear aperture of the lens.

[0064] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -3 < f2 / f < -0.3; the radius of curvature R3 of the object side surface of the second lens and the radius of curvature R4 of the image side surface of the second lens satisfy: 0.1 < R3 / R4 < 2. Meeting the above conditions, the second lens has a negative refractive power, which is beneficial to expanding the light rays refracted by the first reflecting element and making them propagate in the subsequent lens group at an angle close to the optical axis. At the same time, it can effectively correct the aberration brought by the first reflecting element and improve the overall imaging quality.

[0065] In some embodiments, the effective focal length f of the optical lens and the radius of curvature R5 of the object side surface of the third lens satisfy: -0.5 < R5 / f < -0.2; the effective focal length f of the optical lens and the radius of curvature R7 of the object side surface of the fourth lens satisfy: R7 / f > 0.1. Meeting the above conditions is beneficial to correcting the aberration and distortion of the system and improving the overall imaging quality.

[0066] In some embodiments, the propagation length CT1 of the light rays on the optical axis of the first reflecting element and the sum CT of the central thicknesses of each lens in the second group on the optical axis Q2 satisfy: 2.5 < CT1 / CT Q2 < 4. Meeting the above conditions, on the one hand, it ensures that the light rays can pass through a longer optical path in a limited space, thereby achieving a longer focal length. On the other hand, it can effectively reduce the total length of the rear lens group and better achieve the balance between long focal length performance and miniaturization.

[0067] In some embodiments, the back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.6 < BFL / f < 0.9; the back focal length BFL of the optical lens and the total length TTL on the optical axis from the object side surface of the first reflecting element to the imaging surface satisfy: 0.38 < BFL / TTL < 0.48. Meeting the above conditions can make the lens have a larger back focal length, reserve enough space for the placement of the imaging chip, prevent interference between components in the lens module, and at the same time enable the light rays to pass through a longer optical path in a limited space, enabling the lens to achieve a longer focal length.

[0068] In some embodiments, the refractive index Nd1 of the first reflecting element satisfies: Nd1 < 1.6. Meeting the above conditions, the first reflecting element adopts an aspherical prism with a diopter, that is, an aspherical design is adopted on the object side surface and / or the image side surface of the prism, and an injection molding process is used to realize the integral molding of the product, which is beneficial to reducing the weight and manufacturing cost of the reflecting element, reducing the processing difficulty, and providing advantages for realizing large prism anti-shake.

[0069] In some embodiments, the focal length f1 of the first reflecting element and the focal length f2 of the second lens satisfy: -3 < f1 / f2 < -0.3. Meeting the above conditions can effectively converge and reflect the light rays with a large field of view by the first reflecting element. After passing through the second lens, the light rays are expanded to a certain extent, making the light rays approach parallel to the optical axis and enter the subsequent optical elements, reducing the difficulty of aberration correction.

[0070] In some embodiments, the propagation length CT1 of the light rays on the optical axis of the first reflecting element and the total length of the object side surface of the first reflecting element to the imaging surface on the optical axis satisfy: 0.35 < CT1 / TTL < 0.45. Meeting the above conditions, when the light rays enter the first reflecting element, they will be reflected once. By setting a longer reflection path, this enables the light rays to pass through a longer optical path within a limited space, thereby achieving a longer focal length.

[0071] In some embodiments, the half-aperture DM1 of the first reflecting element in the wide-side direction for light passing through and the maximum effective half-aperture DM of the lenses in the second group Q2 satisfy: 0.5 < DM Q2 / DM1 < 0.7. Meeting the above conditions can make the second group have a smaller light-passing aperture, which better meets the characteristics of a thin and light periscope telephoto lens.

[0072] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the optical lens and the entrance pupil diameter EPD of the optical lens satisfy: 1.7 < IH / EPD < 1.8. Meeting the above conditions can increase the width of the light beam entering the optical lens, improving the brightness at the image plane of the optical lens and avoiding vignetting.

[0073] In some embodiments, the optical lens satisfies the following conditional expressions: 10mm < f < 15mm; FOV < 45°; 19mm < TTL < 23mm; Fno < 2.5; 8mm < IH < 11mm. 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 length of the object side surface of the first reflecting element to the imaging surface on the optical axis (i.e., the propagation path length of the light rays from the object side surface of the first reflecting element to the imaging surface along the optical axis), Fno represents the aperture value of the optical lens, and IH represents the true image height corresponding to the maximum field of view angle of the optical lens. Meeting the above ranges, the optical lens has at least one or more advantages such as long focal length, large image plane, and large aperture.

[0074] In some embodiments, the first reflective element and lens material in the optical lens provided by the present invention may be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. 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 reflective element, the second lens, the third lens, and the fourth lens provided by the present invention may be made of plastic material, which can make the structure of the lens more compact, can better achieve the balance between miniaturization of the lens and high image quality, and reduce costs.

[0075] In some embodiments, the first reflective element adopts an aspheric prism, the reflective surface of the first reflective element is a plane, the second lens, the third lens, and the fourth lens can adopt a spherical lens or an aspheric lens, and the aspheric structure can effectively reduce the aberration of the optical system compared to the spherical structure, thereby reducing the number of lenses and reducing the size of the lenses, and better realizing the miniaturization of the lens. More specifically, the object side and the image side of the first reflective element of the present invention are both aspheric, and the second lens, the third lens, and the fourth lens are all aspheric lenses.

[0076] In various embodiments of the present invention, when the lens and the first reflective element are aspherical lenses, the shapes of the aspherical surfaces of the optical lens satisfy the following equations:

[0077] ;

[0078] Among them, z is the distance between the surface and the vertex of the surface in the direction of the optical axis, h is the distance from the optical axis to the surface, c is the curvature of the surface vertex, K is the quadratic surface coefficient, B, C, D, E, F, G, and H are the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, and sixteenth-order surface coefficients respectively.

[0079] 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.

[0080] Example 1

[0081] See also Figure 1 , Figure 1Schematic 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), a first reflective element L1, a stop ST, a second group Q2, and a filter G1; the second group Q2 has a negative optical power and includes, in order from the light propagation direction along the optical axis, a second lens L2, a third lens L3, and a fourth lens L4. 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.

[0082] Among them, the first reflective element L1 has a positive optical focal length, and the first reflective element L1 adopts a folding prism design, which can be specifically an isosceles right-angle prism, including an object side surface (light incident surface) S1, a reflection surface R0 and an image side surface (light exit surface) S2; its object side surface S1 is a concave surface, and its image side surface S2 is a convex surface; its object side surface S1 and image side surface S2 are both aspherical surfaces, and the reflection surface R0 is a plane. The reflection surface of the prism forms an angle of 45° with the optical axes of the object side surface and the image side surface of the prism. It can be understood that its object side surface S1 faces the object side, and its image side surface S2 faces the imaging surface.

[0083] The second lens L2 has negative refractive power, its object-side surface S3 is convex, and its image-side surface S4 is concave;

[0084] The third lens L3 has positive refractive power, its object-side surface S5 is concave, and its image-side surface S6 is convex;

[0085] The fourth lens L4 has negative refractive power, its object-side surface S7 is convex, and its image-side surface S8 is concave;

[0086] The object side surface S9 and the image side surface S10 of the filter G1 are both planes;

[0087] The imaging surface S11 is a plane.

[0088] The first reflective element L1 , the second lens L2 , the third lens L3 , and the fourth lens L4 are all plastic aspherical lenses.

[0089] The relevant parameters of each lens in the optical lens 100 in Example 1 are shown in Table 1-1.

[0090] Table 1-1

[0091]

[0092] The surface parameters of the aspheric lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0093] Table 1-2

[0094]

[0095] In this embodiment, the magnification chromatic aberration curve, the distortion curve, and the axial aberration curve of the optical lens 100 are respectively as follows: Figure 2 , Figure 3 , Figure 4 shown.

[0096] Figure 2 The magnification chromatic aberration curve of Example 1 is shown, which represents the chromatic aberration of each wavelength relative to the central wavelength (0.55 μm) at different image heights on the imaging surface, the horizontal axis represents the 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 chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2 μm, indicating that the optical lens 100 can correct chromatic aberration very well.

[0097] Figure 3 The 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 image height (unit: mm). It can be seen from the figure that the distortion of the optical lens is controlled within ±0.5%, indicating that the optical lens 100 can correct the distortion well.

[0098] Figure 4 The axial aberration curve of Example 1 is shown, which represents the aberration of each wavelength on the optical axis at the imaging plane, the horizontal axis represents the axial aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the offset of the axial aberration is controlled within ±0.05mm, indicating that the optical lens 100 can better correct the axial aberration.

[0099] Example 2

[0100] See also Figure 5 , 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 differences of this embodiment are: the third lens L3 has negative focal power; the fourth lens L4 has positive focal power; the image side surface S6 of the third lens L3 is a concave surface; the image side surface S8 of the fourth lens L4 is a convex surface; the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0101] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0102] Table 2-1

[0103]

[0104] The surface parameters of the aspheric lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0105] Table 2-2

[0106]

[0107] In this embodiment, the magnification chromatic aberration curve, the distortion curve, and the axial aberration curve of the optical lens 200 are respectively as follows: Figure 6 , Figure 7 , Figure 8 shown.

[0108] from Figure 6 It can be seen that the chromatic aberration between the longest wavelength and the shortest wavelength is controlled within ±2 μm, indicating that the optical lens 200 can correct chromatic aberration very well.

[0109] from Figure 7 It can be seen that the distortion of the optical lens is controlled within ±1%, indicating that the optical lens 200 can correct the distortion well.

[0110] from Figure 8 It can be seen that the offset of the axial aberration is controlled within ±0.05 mm, indicating that the optical lens 200 can correct the axial aberration well.

[0111] Example 3

[0112] See also Fig. 9 , 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 differences of this embodiment are: the fourth lens L4 has positive focal power; the object side surface S1 of the first reflective element L1 is a convex surface; the image side surface S8 of the fourth lens L4 is a convex surface; the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0113] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0114] Table 3-1

[0115]

[0116] The surface parameters of the aspheric lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0117] Table 3-2

[0118]

[0119] In this embodiment, the magnification chromatic aberration curve, the distortion curve, and the axial aberration curve of the optical lens 300 are respectively as follows: Fig.10 , Fig.11 , Fig.12 shown.

[0120] from Fig.10It can be seen that the chromatic aberration between the longest wavelength and the shortest wavelength is controlled within ±2 μm, indicating that the optical lens 300 can correct chromatic aberration very well.

[0121] from Fig.11 It can be seen that the distortion of the optical lens is controlled within ±1%, indicating that the optical lens 300 can correct the distortion well.

[0122] from Fig.12 It can be seen that the offset of the axial aberration is controlled within ±0.05 mm, indicating that the optical lens 300 can correct the axial aberration well.

[0123] Example 4

[0124] See also Fig.13 , shown is a schematic diagram of the structure of the optical lens 400 provided in Example 4 of the present invention. Compared with Example 1, the main differences of this embodiment are: the fourth lens L4 has positive focal power; the object side surface S1 of the first reflective element L1 is a convex surface; the object side surface S3 of the second lens L2 is a concave surface; the image side surface S4 of the second lens L2 is a convex surface; the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0125] The relevant parameters of each lens in the optical lens 400 in Example 4 are shown in Table 4-1.

[0126] Table 4-1

[0127]

[0128] The surface parameters of the aspheric lens of the optical lens 400 in Example 4 are shown in Table 4-2.

[0129] Table 4-2

[0130]

[0131] In this embodiment, the magnification chromatic aberration curve, the distortion curve, and the axial aberration curve of the optical lens 400 are respectively as follows: Fig.14 , Fig.15 , Fig.16 shown.

[0132] from Fig.14 It can be seen that the chromatic aberration between the longest wavelength and the shortest wavelength is controlled within ±2 μm, indicating that the optical lens 400 can correct chromatic aberration very well.

[0133] from Fig.15 It can be seen that the distortion of the optical lens is controlled within ±0.5%, indicating that the optical lens 400 can correct the distortion well.

[0134] from Fig.16It can be seen that the offset of the axial aberration is controlled within ±0.05 mm, indicating that the optical lens 400 can correct the axial aberration well.

[0135] Example 5

[0136] See also Fig.17 , shown is a schematic diagram of the structure of the optical lens 500 provided in Example 5 of the present invention. Compared with Example 1, the main differences of this embodiment are: the third lens L3 has negative optical power; the fourth lens L4 has positive optical power; the object side surface S1 of the first reflective element L1 is a convex surface; the image side surface S6 of the third lens L3 is a concave surface; the optical parameters such as the curvature radius of each lens surface and the lens thickness are different.

[0137] The relevant parameters of each lens in the optical lens 500 in Example 5 are shown in Table 5-1.

[0138] Table 5-1

[0139]

[0140] The surface parameters of the aspheric lens of the optical lens 500 in Example 5 are shown in Table 5-2.

[0141] Table 5-2

[0142]

[0143] In this embodiment, the magnification chromatic aberration curve, the distortion curve, and the axial aberration curve of the optical lens 500 are respectively as follows: Fig.18 , Fig.19 , Fig. 20 shown.

[0144] from Fig.18 It can be seen that the chromatic aberration between the longest wavelength and the shortest wavelength is controlled within ±2 μm, indicating that the optical lens 500 can correct chromatic aberration very well.

[0145] from Fig.19 It can be seen that the distortion of the optical lens is controlled within ±1%, indicating that the optical lens 500 can correct the distortion well.

[0146] from Fig. 20 It can be seen that the offset of the axial aberration is controlled within ±0.05 mm, indicating that the optical lens 500 can correct the axial aberration well.

[0147] Please refer to Table 6, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f of the optical lens, the total length TTL from the object side of the first reflective element to the imaging surface on the optical axis, the aperture value Fno, 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.

[0148] Table 6

[0149]

[0150] In summary of the above embodiments, the beneficial effects of the optical lens provided by the present invention are as follows: the combination of an aspherical prism and a lens is adopted. Due to the refractive power of the prism itself and the non-curved surface, the aberrations in the optical system are well balanced. The light with a large field of view and a large aperture at a distance is effectively compressed by the prism before entering the subsequent lens, which can reduce the number of subsequent lenses and reduce costs. In addition, while increasing the amount of light entering and improving the optical performance of the system, the optical aperture of the lens is effectively compressed, thereby solving the problem of the aperture limitation of the subsequent lens under the aperture, and having the characteristics of miniaturization and thinness.

[0151] 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.

[0152] 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: From the object side to the imaging surface, it sequentially includes: a first reflecting element with positive optical power and a second group with negative optical power; The object side surface of the first reflecting element is concave or convex, the image side surface of the first reflecting element is convex, and a reflecting surface is provided between the object side surface and the image side surface of the first reflecting element; the reflecting surface of the first reflecting element forms a 45° angle with the optical axes of the object side surface and the image side surface of the first reflecting element; the first reflecting element adopts an integrally formed structure; The second group consists of three lenses, and sequentially includes from the object side to the imaging surface along the optical axis: a second lens with negative optical power, a third lens with optical power, and a fourth lens with optical power; The object side surface of the third lens is concave; The object side surface of the fourth lens is convex; The focal length f1 of the first reflective element and the combined focal length f Q2 Satisfied: -0.6 <f1 / f Q2 <0.

2. The optical lens according to claim 1, characterized in that: Both the object side surface and the image side surface of the first reflecting element are aspherical surfaces.

3. The optical lens according to claim 2, characterized in that: The object side surface, the image side surface, and the reflecting surface of the first reflecting element are all rectangular, and the clear aperture semi-diameter DM1 in the wide side direction of the first reflecting element satisfies: 3.6mm ≤ DM1 < 4.5mm; the clear aperture semi-diameter DM1 in the wide side direction of the first reflecting element and the clear aperture semi-diameter DL1 in the long side direction of the first reflecting element satisfy: 0.7 < DM1 / DL1 < 1.

4. 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: 0.7 < IH / f < 0.

8.

5. The optical lens according to claim 1, characterized in that: The total length TTL on the optical axis from the object side surface of the first reflecting element to the imaging surface and the effective focal length f of the optical lens satisfy: 1.5 < TTL / f < 2; the total length TTL on the optical axis from the object side surface of the first reflecting element to the imaging surface and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 2 < TTL / IH < 2.

8.

6. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the combined focal length f of the second group Q2 Satisfied: -25 <f Q2 / f<-1.

7. 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 reflecting element satisfy: 0.3 < f1 / f < 1; the effective focal length of the optical lens and the curvature radius R2 of the image side surface of the first reflecting element satisfy: -1 < R2 / f < -0.

2.

8. 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: -3 < f2 / f < -0.3; 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: 0.1 < R3 / R4 < 2.

9. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the curvature radius R5 of the object side surface of the third lens satisfy: -0.5 < R5 / f < -0.2; the effective focal length f of the optical lens and the curvature radius R7 of the object side surface of the fourth lens satisfy: 0.1 < R7 / f ≤ 19.

248.

10. The optical lens according to claim 1, characterized in that: The sum of the propagation length CT1 of the light on the optical axis of the first reflective element and the center thickness CT of each lens in the second group on the optical axis Q2 Satisfaction: 2.5 <CT1 / CT Q2 <4.

11. The optical lens according to claim 1, characterized in that: The back focal length BFL of the optical lens and the effective focal length f of the optical lens satisfy: 0.6 < BFL / f < 0.9; the back focal length BFL of the optical lens and the total length TTL on the optical axis from the object side surface of the first reflecting element to the imaging surface satisfy: 0.38 < BFL / TTL < 0.48.

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