Optical lens

Abstract

The present invention provides an optical lens, which sequentially includes, from the object side to the image side: a catadioptric element, the reflection surface of the catadioptric element forms an angle of 45° with the optical axis where it is located; a first lens with positive optical power, the object side surface of which is convex and the image side surface of which is concave; a second lens with negative optical power, the object side surface of which is convex and the image side surface of which is concave; a third lens with optical power, the object side surface of which is concave and the image side surface of which is convex; a fourth lens with positive optical power, the object side surface of which is concave and the image side surface of which is convex; the first lens adopts a trimmed lens forming process, and the first lens satisfies the conditional formula: 0.95 < D1min / D1max < 0.99, where D1max represents the maximum optical aperture of the first lens and D1min represents the minimum optical aperture of the first lens. The optical lens of the present invention adopts a trimmed lens forming process to compress the lateral dimension of the lens aperture, and can preferably realize the design of a periscope lens with a large aperture and a large field of view, and can meet the design requirements of the thinning of smart phones.

Description

Technical Field

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

[0002] Telephoto cameras can meet consumers' needs for photographing specific targets, but the total optical length of traditional telephoto cameras is too large and does not meet the requirements of lightweight design of smartphones.

[0003] In order to give mobile phone photography a more powerful telephoto feature, the periscope mobile phone lens has been a hot topic since its birth and has become a standard feature of some flagship imaging mobile phones. In order to pursue higher quality and more stable telephoto performance, the optical system needs to have a larger aperture and light throughput. However, after the optical path of the periscope telephoto lens passes through the prism and other reflective parts, the size of the lens aperture cannot be increased due to the thickness of the mobile phone, which hinders the development of telephoto lenses with large apertures, large fields of view, and high-quality imaging. Moreover, the increase in the aperture of the periscope telephoto lens will also bring about the problem of module motor mismatch, and thus the inability to complete the autofocus of the drive lens. In addition, the current periscope telephoto lens will have a very obvious purple-edge halo effect in actual shooting, which also hinders the improvement and optimization of the image quality of mobile phone lenses. Summary of the invention

[0004] The 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] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] An optical lens, comprising, from the object side to the image side, the following:

[0007] A reflective element, wherein the angle between the reflective surface of the reflective element and the optical axis is 45°;

[0008] The first lens has positive refractive power, its object side surface is convex, and its image side surface is concave;

[0009] The second lens has a negative optical power, its object side surface is convex, and its image side surface is concave;

[0010] a third lens having optical power, whose object side surface is concave and whose image side surface is convex;

[0011] The fourth lens element has positive refractive power, its object-side surface is concave, and its image-side surface is convex.

[0012] Among them, the first lens is formed by a trimming lens forming process, and the first lens satisfies the conditional formula: 0.95 < D1min / D1max < 0.99, where D1max represents the maximum optical aperture of the first lens, and D1min represents the minimum optical aperture of the first lens.

[0013] The optical lens satisfies the conditional formula: 0.55 < IH / f < 0.65, where IH represents the image height corresponding to the maximum field of view angle of the optical lens, and f represents the effective focal length of the optical lens.

[0014] Further preferably, the optical lens satisfies the conditional formula: 0.95 < TTL / f < 1.05; where TTL represents the distance from the object side of the first lens to the imaging plane on the optical axis, and f represents the effective focal length of the optical lens.

[0015] Further preferably, the optical lens satisfies the conditional formula: 1.6 < TTL / IH < 1.7; where TTL represents the distance from the object side of the first lens to the imaging plane on the optical axis, and IH represents the image height corresponding to the maximum field of view angle of the optical lens.

[0016] Further preferably, the optical lens satisfies the conditional formula: 0.4 < f1 / f < 0.6, where f1 represents the effective focal length of the first lens, and f represents the effective focal length of the optical lens.

[0017] Further preferably, the optical lens satisfies the conditional formula: 0.01 < R1 / R2 < 0.1; 3 < R2 / f < 20; where R1 represents the radius of curvature of the object side of the first lens, R2 represents the radius of curvature of the image side of the first lens, and f represents the effective focal length of the optical lens.

[0018] Further preferably, the optical lens satisfies the conditional formula: -0.8 < f2 / f < -0.4, 1.5 < R3 / R4 < 5; where f2 represents the effective focal length of the second lens, f represents the effective focal length of the optical lens, R3 represents the radius of curvature of the object side of the second lens, and R4 represents the radius of curvature of the image side of the second lens.

[0019] Further preferably, the optical lens satisfies the conditional formula: -0.2 < R5 / f < -0.1, -0.19 < R6 / f < -0.15; where R5 represents the radius of curvature of the object side of the third lens, R6 represents the radius of curvature of the image side of the third lens, and f represents the effective focal length of the optical lens.

[0020] Further preferably, the optical lens satisfies the conditional expressions: 1.5 < f4 / f < 6, 4 < R7 / R8 < 18; where f4 represents the effective focal length of the fourth lens, f represents the effective focal length of the optical lens, R7 represents the radius of curvature of the object side surface of the fourth lens, and R8 represents the radius of curvature of the image side surface of the fourth lens.

[0021] Further preferably, the optical lens satisfies the conditional expressions: -25 < R7 / f < -5, -3 < R8 / f < -0.8; where R7 represents the radius of curvature of the object side surface of the fourth lens, R8 represents the radius of curvature of the image side surface of the fourth lens, and f represents the effective focal length of the optical lens.

[0022] Further preferably, the optical lens satisfies the conditional expressions: 4.5 < CT1 / CT2 < 5.5, 0.4 < CT3 / CT4 < 0.9; where CT1 represents the central thickness of the first lens, CT2 represents the central thickness of the second lens, CT3 represents the central thickness of the third lens, and CT4 represents the central thickness of the fourth lens.

[0023] Further preferably, the optical lens satisfies the conditional expressions: 0.5 < BFL / TTL < 0.6, 0.5 < BFL / f < 0.6; where TTL represents the distance from the object side surface of the first lens to the imaging surface on the optical axis, f represents the effective focal length of the optical lens, and BFL represents the back focal length of the optical lens.

[0024] Compared with the prior art, when the object-side light beam of the optical lens of the present invention passes through the refractive-reflective element, it is reflected on the reflective surface of the refractive-reflective element, causing the optical axis to turn by 90°. Then it passes through the first lens, the second lens, the third lens, and the fourth lens in sequence, and finally undergoes the filtering process of the filter to complete image acquisition on the photosensitive chip; and because the first lens adopts the lens slicing process, while ensuring that the lens has a large light-gathering aperture, it minimizes the lateral size of the lens to the greatest extent, thereby better realizing the periscope imaging effect of the large aperture and large field of view of the lens, and also meeting the development trend of ultra-thinning of portable electronic devices such as mobile phones. Description of the Drawings

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and easy to understand from the description of the embodiments in conjunction with the following drawings, where:

[0026] Figure 1 It is a cross-sectional schematic diagram of the trimmed lens of the first lens provided by the embodiment of the present invention.

[0027] Figure 2 It is a structural schematic diagram of the optical lens in Embodiment 1 of the present invention.

[0028] Figure 3 Graph showing the axial aberration of the optical lens in Example 1 of the present invention.

[0029] Figure 4 4 is a distortion curve diagram of the optical lens in Example 1 of the present invention.

[0030] Figure 5 : is the magnification chromatic aberration curve of the optical lens in Example 1 of the present invention.

[0031] Figure 6 Schematic diagram of the structure of the optical lens in Example 2 of the present invention.

[0032] Figure 7 Graph showing the axial aberration of the optical lens in Embodiment 2 of the present invention.

[0033] Figure 8 4 is a distortion curve diagram of the optical lens in Example 2 of the present invention.

[0034] Fig. 9 : is the magnification chromatic aberration curve of the optical lens in Example 2 of the present invention.

[0035] Fig.10 Schematic diagram of the structure of the optical lens in Example 3 of the present invention.

[0036] Fig.11 Graph showing the axial aberration of the optical lens in Embodiment 3 of the present invention.

[0037] Fig.12 3 is a distortion curve diagram of the optical lens in Example 3 of the present invention.

[0038] Fig.13 : is the magnification chromatic aberration curve of the optical lens in Example 3 of the present invention. DETAILED DESCRIPTION

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] The optical lens provided by the embodiment of the present invention is composed of a folding and reflecting element and four lenses. Specifically, the optical lens includes, from the object side to the image side, a folding and reflecting element, a first lens, a second lens, a third lens, a fourth lens and a filter.

[0047] Specifically, the included angle between the reflecting surface of the catadioptric element and the optical axis where it is located is 45°; the catadioptric element is used to turn the incident optical path, and the catadioptric element can adopt a right-angle catadioptric prism, and the included angle between its reflecting surface and the optical axis where it is located is 45°; the catadioptric prism can be made of glass or plastic material.

[0048] The first lens has a positive focal power, its object side is convex, and its image side is concave.

[0049] The second lens has a negative focal power, its object side is convex, and its image side is concave.

[0050] The third lens has a positive or negative focal power, its object side is concave, and its image side is convex.

[0051] The fourth lens has a positive focal power, its object side is concave, and its image side is convex.

[0052] In some embodiments, the optical lens may further include a diaphragm, and the diaphragm may be located between the catadioptric element and the first lens; it can be understood that the diaphragm is used to limit the amount of incident light to change the brightness of the image.

[0053] When the object-side light beam of the optical lens of the present invention passes through the catadioptric element, it is reflected on the reflecting surface of the prism, causing the optical axis to turn 90°. Then it passes through the first lens, the second lens, the third lens, and the fourth lens in sequence, and finally undergoes the filtering process of the filter to complete image acquisition on the photosensitive chip (imaging surface).

[0054] In some embodiments, the first lens adopts a trimmed lens forming process, and the first lens satisfies the conditional formula: 0.95 < D1min / D1max < 0.99, where D1max represents the maximum optical aperture of the first lens, and D1min represents the minimum optical aperture of the first lens; more specifically, D1min > 5 mm. Generally speaking, the effective aperture of the first lens (close to the prism) is the largest in the system, and the amount of incident light of the optical system is also largely determined by the aperture size of the first lens. The shape of a conventional optical lens in the direction perpendicular to the optical axis is circular. In order to increase the amount of incident light of the periscope lens, the first lens is injection molded by a trimmed lens forming process, so that the lateral dimension of the first lens is trimmed to a certain extent (for the schematic cross-sectional view of the trimmed shape in the lateral direction, see Figure 1 ), effectively compressing the lateral dimension of the lens in the mobile phone lens module, and minimizing the lateral dimension of the lens to the greatest extent while ensuring that the lens has a large light passing aperture, so as to better achieve the periscope imaging effect of large aperture, large aperture ratio, and large field of view of the optical lens, and also meet the development trend of ultra-thinness of portable electronic devices such as mobile phones.

[0055] It should be noted that after the light path of the periscope optical lens in the present invention is turned by the catadioptric element (prism), the lens lies horizontally inside the mobile phone. Therefore, the aperture of the lens is limited by the thickness of the mobile phone itself. The lens of the first lens of the present invention will be trimmed in the thickness direction of the mobile phone and can maintain the original size unchanged in another direction perpendicular thereto. The first lens is formed by trimming the lens, which can effectively increase the light input and increase the aperture value of the system. More specifically, the trimmed lens of the first lens of the present invention is formed by injection molding with a mold.

[0056] In an embodiment of the present invention, the first lens is a plastic lens and is formed by a lens trimming process. The refractive index of the material of the first lens is between 1.5 and 1.6, and the Abbe number is between 50 and 60. By controlling the range of the refractive index and the Abbe number of the first lens, the stress influence of the lens material in product manufacturing can be reduced, the process difficulty of slicing the lens can be reduced, and the stability of injection molding of the trimmed lens and the product yield can be improved.

[0057] In some embodiments, the refractive index of the material of the second lens is between 1.5 and 1.7, and the Abbe number is between 18 and 65; the refractive index of the material of the fourth lens is between 1.5 and 1.7, and the Abbe number is between 22 and 60. By restricting the refractive index and the Abbe number of the second lens and the fourth lens, it helps the object-side light beam to smoothly transition to the subsequent third lens and fourth lens after being compressed by the first lens and the second lens, thereby ensuring high-quality imaging and low sensitivity of the optical lens. At the same time, by reasonably matching the refractive index and the Abbe number of the lens, it is beneficial to balance the purple wavelength aberration of the optical lens and helps to improve the purple fringing effect existing in the actual shooting effect of the periscope telephoto lens.

[0058] Further preferably, the optical lens satisfies the conditional formula: 0.55 < IH / f < 0.65, where IH represents the image height corresponding to the maximum field of view angle of the optical lens, and f represents the effective focal length of the optical lens. Meeting the above conditions can not only achieve the telephoto characteristics of the lens to meet the local shooting requirements, but also achieve the large image plane characteristics of the lens, be able to carry a larger-sized chip, and achieve high-definition imaging of the lens.

[0059] Further preferably, the optical lens satisfies the conditional formula: 0.95 < TTL / f < 1.05; where TTL represents the distance from the object side surface of the first lens to the imaging surface on the optical axis, and f represents the effective focal length of the optical lens. Meeting the above conditions ensures that while the lens has a long focal length, the total length of the lens is small, which is beneficial to achieving the balance of telephoto and miniaturization and is convenient to be mounted on a thin and light electronic device.

[0060] Further preferably, the optical lens satisfies the conditional formula: 1.6 < TTL / IH < 1.7; where TTL represents the distance from the object side of the first lens to the imaging plane on the optical axis, and IH represents the image height corresponding to the maximum field of view angle of the optical lens. Meeting the above conditions ensures that, with the same total length of the lens, a larger imaging surface is obtained, enabling a larger-sized imaging chip to be matched to achieve high-definition imaging, and better achieving the balance between the small total length and the large imaging surface of the lens.

[0061] Further preferably, the optical lens satisfies the conditional formula: 0.4 < f1 / f < 0.6, where f1 represents the effective focal length of the first lens, and f represents the effective focal length of the optical lens. Meeting the above conditions can endow the first lens with a large positive refractive power, which is beneficial for collecting light at large angles, while reducing the height of the light incident on the first lens, facilitating the miniaturization of the lens.

[0062] Further preferably, the optical lens satisfies the conditional formula: 0.01 < R1 / R2 < 0.1; where R1 represents the curvature radius of the object side of the first lens, and R2 represents the curvature radius of the image side of the first lens. Meeting the above conditions, by controlling the shapes of the object side and the image side of the first lens, on the one hand, the difficulty of lens manufacturing can be effectively reduced, providing a greater possibility for realizing edge-cut lenses; on the other hand, while effectively increasing the light input of the optical lens, the spherical aberration and astigmatism of the system can be corrected, improving the imaging quality of the lens.

[0063] Further preferably, the optical lens satisfies the conditional formula: 3 < R2 / f < 20; where R2 represents the curvature radius of the image side of the first lens, and f represents the effective focal length of the optical lens. Meeting the above conditions, by reasonably controlling the ratio of the curvature radius of the image side of the first lens to the focal length of the optical lens, the optical deflection angle borne by the lens can be effectively distributed, thereby ensuring the smooth propagation of the object-side light beam after refraction by the first lens in the subsequent system, enabling the system to have better imaging quality and lower sensitivity.

[0064] Further preferably, the optical lens satisfies the conditional formulas: -0.8 < f2 / f < -0.4, 1.5 < R3 / R4 < 5; where f2 represents the effective focal length of the second lens, f represents the effective focal length of the optical lens, R3 represents the curvature radius of the object side of the second lens, and R4 represents the curvature radius of the image side of the second lens. Meeting the above conditions can effectively diverge the light trend emerging from the first lens, enabling the light to transition smoothly to the rear, reducing the difficulty of aberration correction; at the same time, it can also enable the light emerging from the first lens to have a larger light receiving surface when entering the rear optical system, achieving a larger light input, which is beneficial for increasing the relative illumination of the captured image.

[0065] Further preferably, the optical lens satisfies the conditional expressions: -5 < f3 / f < 6.5, 1.5 < f4 / f < 6; where f3 represents the effective focal length of the third lens, f4 represents the effective focal length of the fourth lens, and f represents the effective focal length of the optical lens. Meeting the above conditions can reasonably configure the refractive power relationship between the third lens and the fourth lens, making the optical power distribution of the entire optical lens more balanced, effectively promoting the aberration balance of the optical lens, improving the imaging quality of the lens, having a wider depth of focus, and enabling the imaging light to smoothly enter the image sensor for stable imaging, achieving a clear shooting effect for long-distance telephoto shooting.

[0066] Further preferably, the optical lens satisfies the conditional expressions: -0.2 < R5 / f < -0.1, -0.19 < R6 / f < -0.15; where R5 represents the curvature radius of the object side surface of the third lens, R6 represents the curvature radius of the image side surface of the third lens, and f represents the effective focal length of the optical lens. Meeting the above conditions is conducive to the smooth transition of light by reasonably setting the meniscus surface shape of the third lens, while correcting various aberrations of the optical lens and improving the imaging quality of the optical lens.

[0067] Further preferably, the optical lens satisfies the conditional expressions: 4 < R7 / R8 < 18, -25 < R7 / f < -5, -3 < R8 / f < -0.8; where f represents the effective focal length of the optical lens, R7 represents the curvature radius of the object side surface of the fourth lens, and R8 represents the curvature radius of the image side surface of the fourth lens. Meeting the above conditions can ensure that the curvature radius of the fourth lens is of appropriate size, guarantee the processing quality of the fourth lens, make the light smoothly converge on the imaging surface, and reduce the sensitivity of the entire system. In addition, by controlling the curvature radius of the fourth lens and the effective focal length of the fourth lens, a stable large image plane high-quality imaging effect can be obtained for the optical system, and the optical aperture size of the fourth lens can be effectively restricted, thus avoiding the problem that the lens aperture is too large to be adapted to the size of the commonly used module motor.

[0068] Further preferably, the optical lens satisfies the conditional expressions: 4.5 < CT1 / CT2 < 5.5, 0.4 < CT3 / CT4 < 0.9; where CT1 represents the central thickness of the first lens, CT2 represents the central thickness of the second lens, CT3 represents the central thickness of the third lens, and CT4 represents the central thickness of the fourth lens. Meeting the above conditions is conducive to reasonably configuring the shapes and curvatures of the lenses, reducing the difficulty and sensitivity of the lens forming process, improving the processability of the optical lens, while also being able to compress the size of the optical system, reduce the overall length of the lens group in the mobile phone lens module, and the assembly structure is compact, meeting the development requirements of the miniaturization of the mobile phone lens module.

[0069] Further preferably, the optical lens satisfies the conditional formula: 2.5 < CT1 / CT4 < 4.5; where CT1 represents the central thickness of the first lens, and CT4 represents the central thickness of the fourth lens. By satisfying the above conditions, the ratio of the central thickness of the first lens to the central thickness of the fourth lens can be controlled, enabling the central thickness of the first lens to be greater than that of the fourth lens, reducing the deflection angle of the incident light on the first lens, and decreasing the sensitivity of the first lens in the entire optical lens. At the same time, it helps the optical lens correct chromatic aberration and spherical aberration, reduce the introduction of aberration, and is beneficial to improving the imaging quality of the optical lens.

[0070] Further preferably, the optical lens satisfies the conditional formulas: 0.5 < BFL / TTL < 0.6, 0.5 < BFL / f < 0.6; where TTL represents the distance from the object side of the first lens to the imaging plane on the optical axis, f represents the effective focal length of the optical lens, and BFL represents the back focal length of the optical lens. By satisfying the above conditions, the lens can have an appropriate back focal length, ensuring the compatibility between the lens and the camera body while making the lens structure more compact.

[0071] Further preferably, the optical lens satisfies the conditional formulas: 1.9mm < EPD / Fno < 2.5mm, 3mm < IH / Fno < 3.5mm; where EPD represents the entrance pupil diameter of the optical lens, Fno represents the aperture value of the optical lens, and IH represents the image height corresponding to the maximum field of view angle of the optical lens. By satisfying the above conditions, through the control of the light passing aperture, aperture value, and image height of the optical lens, it is possible to have a larger light passing amount while ensuring that the optical lens has a large image plane, which is beneficial to the realization of optical image stabilization technology in the periscope telephoto module and improves the imaging quality of the optical lens. In addition, achieving a balance between the aperture value and the light passing aperture is beneficial to the realization of the structural process of the edge-cut lens, effectively avoiding excessive and ineffective edge cutting.

[0072] Further preferably, the optical lens satisfies the conditional formulas: 1 < DM1 / DM4 < 1.3, DM4 < 4.5mm; where DM1 represents the effective optical aperture of the first lens, and DM4 represents the effective optical aperture of the fourth lens. By satisfying the above conditions, through the control of the effective optical apertures of the first and fourth lenses (the head and tail lenses), it is possible to effectively reduce the maximum aperture size of the entire lens while ensuring that the lens has a large aperture, a large image plane, and high-quality imaging effects, thus realizing a small-sized and thin-and-light telephoto lens module. In addition, it can also effectively control the aperture size of the entire lens, which is beneficial to the adaptation of large-aperture optical lenses to conventional motors in mobile phone modules.

[0073] In an embodiment of the present invention, the designed wavelength range of the optical lens is 435nm - 650nm. The maximum field of view (FOV) of the optical lens satisfies: 30° < FOV < 35°. The image height (IH) corresponding to the maximum field of view of the optical lens satisfies: 8mm < IH < 8.5mm. By controlling the image height and field of view of the optical lens and optimizing the aberration of short-wavelength light, it is ensured that while achieving a large image plane and a large field of view, the influence of purple fringing during lens shooting is improved, and the imaging quality is enhanced.

[0074] 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. Additionally, when the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected due to the low dispersion characteristic of the glass itself. The optical lens provided by the present invention can adopt an all-plastic lens structure, which not only enables the lens to have excellent imaging performance but also makes the lens structure relatively compact, and can better achieve the balance between lens miniaturization and high image quality.

[0075] In some embodiments, the first lens, the second lens, the third lens, and the fourth 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 achieving lens miniaturization. More specifically, the first lens, the second lens, the third lens, and the fourth lens of the present invention can all adopt aspherical lenses, which can effectively reduce the aberration of the optical lens, thereby reducing the number of lenses and the size of the lenses, and better achieving lens miniaturization.

[0076] To enable the system to have better optical performance, multiple aspherical lenses are used in the lens. The shapes of the aspherical surfaces of the optical lens satisfy the following equation:

[0077]

[0078] 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 surface vertex, K is the conic coefficient, and B, C, D, E, F, G, H, I, J are the second-order, fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, fourteenth-order, sixteenth-order, eighteenth-order, and twentieth-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 2 , 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, from the object side to the imaging surface S13, a prism Pr, an aperture ST, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4 and a filter G1, and there may be an air gap between any two adjacent lenses.

[0082] The prism Pr adopts a folding prism design, specifically a right-angle triangular prism, including an incident surface S1, a reflection surface R0 and an exit surface S2; the incident surface S1 and the exit surface S2 are both planes. It can be understood that the incident surface S1 faces the object side, and the exit surface S2 faces the first lens L1.

[0083] The first lens L1 has positive refractive power, an object-side surface S3 of the first lens is a convex surface, and an image-side surface S4 of the first lens is a concave surface at the optical axis.

[0084] The second lens L2 has negative refractive power, the object-side surface S5 of the second lens is a convex surface, and the image-side surface S6 of the second lens is a concave surface.

[0085] The third lens L3 has negative refractive power, the object-side surface S7 of the third lens is concave, and the image-side surface S8 of the third lens is convex.

[0086] The fourth lens L4 has positive refractive power, the object-side surface S9 of the fourth lens is a concave surface, and the image-side surface S10 of the fourth lens is a convex surface.

[0087] The object-side surface S11 and the image-side surface S12 of the filter G1 are both planes.

[0088] The imaging surface S13 is a plane.

[0089] The prism Pr may be made of glass or plastic, and the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 are all plastic aspherical lenses.

[0090] Specifically, the first lens L1 is a trimmed plastic lens, which is directly injection molded through a trimming process. Therefore, the diameter of the lens can be further compressed in the thickness direction of the mobile phone, so that the optical lens with large light flux and large field of view can be well adapted to the conventional module assembly of the mobile phone lens, providing greater possibilities for realizing a large aperture, large image surface, and small-volume telephoto lens module.

[0091] Specifically, Figure 1 FIG. 1 is a schematic cross-sectional view of the cut edge shape of the first lens provided in an embodiment of the present invention. In order to clearly reflect the effect of the cut edge lens of the first lens L1, Figure 2 Two dotted lines are drawn along the optical axis in a single direction (in any direction perpendicular to the optical axis) of the first lens L1 in Example 1, and the outer side of the dotted lines represents the portion removed by the slicing lens. More specifically, the trimming amount of the first lens L1 in a single direction in Example 1 is 0.045 mm on one side.

[0092] The relevant parameters of each lens in the optical lens of the first embodiment are shown in Table 1-1.

[0093] Table 1-1

[0094]

[0095] The surface parameters of the aspheric lens of the optical lens 100 in Example 1 are shown in Table 1-2.

[0096] Table 1-2

[0097]

[0098] In this embodiment, the axial aberration curve, the distortion curve, and the magnification chromatic aberration curve of the optical lens 100 are respectively as follows: Figure 3 , Figure 4 , Figure 5 shown.

[0099] Figure 3 The axial aberration curve of Example 1 is shown, which represents the aberration of each wavelength (such as 435nm, 495nm, 555nm, 610nm, 650nm) on the optical axis at the imaging surface, the horizontal axis represents the offset (unit: mm) of the focus point after the light passes through the optical lens, and the vertical axis represents the normalized pupil diameter. It can be seen from the figure that the offset of the axial aberration is controlled within ±0.05 mm, indicating that the optical lens 100 can better correct the axial aberration.

[0100] Figure 4The F-Tanθ distortion curve of the optical lens in Example 1 is shown, where the horizontal axis represents the F-Tanθ distortion (unit: percentage) of light at different image heights on the imaging surface, and the vertical axis represents the image height corresponding to the half field of view (unit: mm). It can be seen from the figure that the distortion value in the full field of view is within 2%, indicating that the distortion of the optical lens 100 is well corrected.

[0101] Figure 5 The magnification chromatic aberration curve of Example 1 is shown, which represents the chromatic aberration of each wavelength (such as 435nm, 495nm, 555nm, 610nm, 650nm) relative to the central wavelength (555nm) at different image heights on the imaging surface, the horizontal axis represents the vertical axis chromatic aberration value of each wavelength relative to the central wavelength (unit: micrometer), and the vertical axis represents the normalized field angle. It can be seen from the figure that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2 micrometers, indicating that the optical lens 100 can perfectly correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image surface.

[0102] according to Figures 3 to 5 It can be seen that the optical lens 100 in this embodiment effectively corrects various aberrations, especially can realize the aberration correction of short wavelength light, effectively improves the purple light halo effect existing in telephoto shooting, improves the imaging quality, and makes the lens have the excellent characteristics of large aperture, large image surface and miniaturization.

[0103] Example 2

[0104] See also Figure 6 , which 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. Specifically, in Example 2, the trimming amount of the first lens L1 in a single direction is 0.076 mm on one side.

[0105] The relevant parameters of each lens in the optical lens 200 in Example 2 are shown in Table 2-1.

[0106] Table 2-1

[0107]

[0108] The surface parameters of the aspheric lens of the optical lens 200 in Example 2 are shown in Table 2-2.

[0109] Table 2-2

[0110]

[0111] In this embodiment, the axial aberration curve, the distortion curve, and the magnification chromatic aberration curve of the optical lens 200 are respectively as follows: Figure 7, Figure 8 , Fig. 9 shown.

[0112] Figure 7 The axial aberration curve of Example 2 is shown. It can be seen from the figure that the offset of the axial aberration is controlled within ±0.05 mm, which means that the optical lens 200 can correct the axial aberration well.

[0113] Figure 8 The F-Tanθ distortion curve of the optical lens in Example 2 is shown. It can be seen from the figure that the distortion value in the whole field of view is within 1.5%, indicating that the distortion of the optical lens 200 is well corrected.

[0114] Fig. 9 The magnification chromatic aberration curve of Example 2 is shown. It can be seen from the figure that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2 microns, indicating that the optical lens 200 can extremely well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane.

[0115] according to Figures 7 to 9 It can be seen that the optical lens 200 in this embodiment effectively corrects various aberrations, especially can realize the aberration correction of short wavelength light, effectively improves the purple light halo effect existing in telephoto shooting, improves the imaging quality, and makes the lens have the excellent characteristics of large aperture, large image surface and miniaturization.

[0116] Example 3

[0117] See also Fig.10 , which is a schematic diagram of the structure of the optical lens 300 provided in Embodiment 3 of the present invention. Compared with Embodiment 1, the main differences of this embodiment are that the third lens L3 has positive focal power, and the optical parameters such as the curvature radius of each lens surface and the lens thickness are different, and the trimming amount of the first lens L1 in a single direction in Embodiment 3 is 0.11 mm on one side.

[0118] The relevant parameters of each lens in the optical lens 300 in Example 3 are shown in Table 3-1.

[0119] Table 3-1

[0120]

[0121] The surface parameters of the aspheric lens of the optical lens 300 in Example 3 are shown in Table 3-2.

[0122] Table 3-2

[0123]

[0124] In this embodiment, the axial aberration curve, the distortion curve, and the magnification chromatic aberration curve of the optical lens 300 are respectively as follows: Fig.11 , Fig.12 , Fig.13 shown.

[0125] Fig.11 The axial aberration curve of Example 3 is shown. It can be seen from the figure that the offset of the axial aberration is controlled within ±0.05 mm, which means that the optical lens 300 can correct the axial aberration well.

[0126] Fig.12 The F-Tanθ distortion curve of the optical lens in Example 3 is shown. It can be seen from the figure that the distortion value in the whole field of view is within 1.5%, indicating that the distortion of the optical lens 300 is well corrected.

[0127] Fig.13 The magnification chromatic aberration curve of Example 3 is shown. It can be seen from the figure that the vertical axis chromatic aberration of the longest wavelength and the shortest wavelength is controlled within ±2 microns μm, indicating that the optical lens 300 can extremely well correct the chromatic aberration of the edge field of view and the secondary spectrum of the entire image plane.

[0128] according to Figures 11 to 13 It can be seen that the optical lens 300 in this embodiment effectively corrects various aberrations, especially can realize the aberration correction of short wavelength light, effectively improves the purple light halo effect existing in telephoto shooting, improves the imaging quality, and makes the lens have the excellent characteristics of large aperture, large image surface and miniaturization.

[0129] Please refer to Table 4, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f, the total optical length TTL, the aperture number Fno, the image height IH, the field of view FOV of the optical lens, and the numerical values ​​corresponding to each conditional expression in the embodiments.

[0130] Table 4

[0131]

[0132] In summary, when the object-side light beam of the optical lens provided by the embodiment of the present invention passes through the folding and reflecting element, it is reflected on the reflective surface of the folding and reflecting element, so that the optical axis turns 90°, and then passes through the first lens, the second lens, the third lens and the fourth lens in sequence, and finally passes through the filtering treatment of the filter to complete the image acquisition on the photosensitive chip; and because the first lens adopts the trimming lens molding process, while ensuring that the lens has a large aperture, the lateral size of the lens is minimized to the greatest extent, so as to better achieve the periscope imaging effect of the lens with a large aperture and a large field of view, and can also meet the development trend of ultra-thin portable electronic devices such as mobile phones. Therefore, the optical lens provided by the present invention optimizes the size of the lens in the radial dimension by reasonably matching the materials and surface shapes of each lens, and can effectively optimize and improve the purple edge effect existing in the actual shooting of the telephoto lens while obtaining a larger image surface and making the optical lens perfectly adaptable to the autofocus drive motor in the conventional image module. In addition, based on the molding process of the trimming lens, the optical lens of the present application adopts a periscope telephoto design scheme with a large aperture and a large field of view, which effectively compresses the lateral size of the lens in the vertical direction of the mobile phone lens module.

[0133] 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.

[0134] 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.

[0135] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and improved concepts of the present invention within the technical scope disclosed by the present invention, and they should be covered by the protection scope of the present invention.

Claims

1. An optical lens, characterized in that: From the object side to the image side, it successively includes: A catadioptric element, the reflection surface of the catadioptric element forms an angle of 45° with the optical axis where it is located; A first lens with positive optical power, its object side surface is convex, and its image side surface is concave; A second lens with negative optical power, its object side surface is convex, and its image side surface is concave; A third lens with optical power, its object side surface is concave, and its image side surface is convex; A fourth lens with positive optical power, its object side surface is concave, and its image side surface is convex; Wherein, the first lens adopts a cutting-edge lens forming process, and the first lens satisfies the conditional formula: 0.95 < D1min / D1max < 0.99, D1max represents the maximum optical aperture of the first lens, and D1min represents the minimum optical aperture of the first lens; The optical lens satisfies the conditional formula: 0.55 < IH / f < 0.65, 1.6 < TTL / IH < 1.7; IH represents the image height corresponding to the maximum field of view angle of the optical lens, f represents the effective focal length of the optical lens, and TTL represents the distance on the optical axis from the object side surface of the first lens to the imaging surface.

2. The optical lens according to claim 1, characterized in that: The optical lens satisfies the conditional formula: 0.95 < TTL / f < 1.05; wherein, TTL represents the distance on the optical axis from the object side surface of the first lens to the imaging surface, and f represents the effective focal length of the optical lens.

3. The optical lens according to claim 1, characterized in that: The optical lens satisfies the conditional formula: 0.4 < f1 / f < 0.6, where f1 represents the effective focal length of the first lens, and f represents the effective focal length of the optical lens.

4. The optical lens according to claim 1, characterized in that: The optical lens satisfies the conditional formula: 0.01 < R1 / R2 < 0.1; 3 < R2 / f < 20; where R1 represents the curvature radius of the object side surface of the first lens, R2 represents the curvature radius of the image side surface of the first lens, and f represents the effective focal length of the optical lens.

5. The optical lens according to claim 1, characterized in that: The optical lens satisfies the conditional formula: -0.8 < f2 / f < -0.4, 1.5 < R3 / R4 < 5; where f2 represents the effective focal length of the second lens, f represents the effective focal length of the optical lens, R3 represents the curvature radius of the object side surface of the second lens, and R4 represents the curvature radius of the image side surface of the second lens.

6. The optical lens according to claim 1, characterized in that: The optical lens satisfies the conditional formula: -0.2 < R5 / f < -0.1, -0.19 < R6 / f < -0.15; where R5 represents the curvature radius of the object side surface of the third lens, R6 represents the curvature radius of the image side surface of the third lens, and f represents the effective focal length of the optical lens.

7. The optical lens according to claim 1, characterized in that: The optical lens satisfies the conditional formula: 1.5 < f4 / f < 6, 4 < R7 / R8 < 18; where f4 represents the effective focal length of the fourth lens, f represents the effective focal length of the optical lens, R7 represents the curvature radius of the object side surface of the fourth lens, and R8 represents the curvature radius of the image side surface of the fourth lens.

8. The optical lens according to claim 1, characterized in that: The optical lens satisfies the conditional formula: -25 < R7 / f < -5, -3 < R8 / f < -0.8; where R7 represents the curvature radius of the object side surface of the fourth lens, R8 represents the curvature radius of the image side surface of the fourth lens, and f represents the effective focal length of the optical lens.

9. The optical lens according to claim 1, characterized in that: The optical lens satisfies the conditional formula: 4.5 < CT1 / CT2 < 5.5, 0.4 < CT3 / CT4 < 0.9; where CT1 represents the central thickness of the first lens, CT2 represents the central thickness of the second lens, CT3 represents the central thickness of the third lens, and CT4 represents the central thickness of the fourth lens.

10. The optical lens according to claim 1, characterized in that: The optical lens satisfies the conditional formula: 0.5 < BFL / TTL < 0.6, 0.5 < BFL / f < 0.6; where TTL represents the distance from the object side of the first lens to the imaging surface on the optical axis, f represents the effective focal length of the optical lens, and BFL represents the back focal length of the optical lens.

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