An ultra-compact hybrid long-focus camera lens, a camera module and an electronic device

Abstract

The application discloses a folded hyper-compact long-focus camera lens, a camera module and electronic equipment. The lens comprises an imaging lens group and a turning lens group arranged along an optical axis from an object plane to an image plane; the imaging lens group comprises a first lens, a second lens, a third lens and a fourth lens arranged along the optical axis from the object plane to the image plane; the turning lens group comprises at least one prism; the first lens is a spherical lens with positive focal power; the second lens is a hyper-surface lens with positive focal power; the third lens is an aspherical lens with negative focal power; and the fourth lens is an aspherical lens with negative focal power. The application significantly reduces the number of lenses required by the imaging lens group, greatly compresses the axial physical total length of the imaging lens group, realizes the light passing capability of a large aperture and small distortion in a full field of view range, and effectively achieves the purpose of miniaturization and thinning of the long-focus camera lens.

Description

Technical Field

[0001] This invention relates to the field of optical imaging technology, and in particular to a hybrid telephoto lens, camera module, and electronic device. Background Technology

[0002] With the continuous improvement of the performance of electronic image sensors, the application requirements of hybrid telephoto lenses in consumer electronics, mobile terminals and other fields are increasing, especially the demand for large-area, high-pixel, and telephoto lenses.

[0003] Currently, most common visible light telephoto lenses employ a periscope optical path structure to compress the overall system length. They typically consist of glass spherical lenses, resin aspherical lenses, and prisms, or only resin aspherical lenses and prisms. However, limitations in the manufacturing process and yield of aspherical lenses restrict their surface design, resulting in a relatively long overall lens length and a large number of required lenses, which hinders miniaturization and thinner designs. Therefore, there is an urgent need for a new lens structure that can effectively shorten the overall optical length, reduce the number of lenses, and maintain large aperture imaging capabilities while maintaining high image quality. Summary of the Invention

[0004] The purpose of this invention is to provide a hybrid telephoto lens, camera module, and electronic device, which aims to solve the problem of how to effectively shorten the total optical length, reduce the number of lenses, and take into account large aperture imaging capabilities while maintaining high imaging quality.

[0005] To solve the above-mentioned technical problems, the objective of this invention is achieved through the following technical solution: providing a hybrid telephoto lens, comprising an imaging lens group and a steering lens group arranged along the optical axis from the object plane to the image plane; the imaging lens group includes a first lens, a second lens, a third lens, and a fourth lens arranged along the optical axis from the object plane to the image plane; the steering lens group includes at least one prism; The first lens is a spherical lens with positive optical power; the second lens is a metasurface lens with positive optical power; the third lens is an aspherical lens with negative optical power; and the fourth lens is an aspherical lens with negative optical power.

[0006] Furthermore, the aforementioned super-hybrid telephoto lens satisfies: 6≤(Fno×Imgh) / L≤13; 110≤(f×FOV) / L≤170; Where Fno is the aperture number, Imgh is the diagonal size of the imaging target surface, L is the total length of the imaging lens group, f is the focal length, and FOV is the diagonal field of view.

[0007] Furthermore, the object-side surface of the first lens is convex near the optical axis, and the image-side surface is concave near the optical axis; the image-side surface of the second lens has microstructures arranged; the object-side surface of the third lens is convex near the optical axis, and the image-side surface is concave near the optical axis; the object-side surface of the fourth lens is convex / concave near the optical axis, and the image-side surface is concave near the optical axis.

[0008] Furthermore, the steering lens assembly includes a prism.

[0009] Furthermore, the first lens and the prism are both made of visible light glass, and the third lens and the fourth lens are both made of visible light resin.

[0010] Furthermore, the super-hybrid telephoto lens also includes an aperture stop, which is located between the second lens and the third lens.

[0011] Furthermore, the super-hybrid telephoto lens also includes a color filter, which is located between the prism and the image plane.

[0012] Furthermore, the focal length f of the hybrid telephoto lens satisfies: f≥18mm.

[0013] Furthermore, the aperture number Fno of the hybrid telephoto lens satisfies: 2.8 ≤ Fno ≤ 4.0.

[0014] Furthermore, the field of view (FOV) of the super-hybrid telephoto lens satisfies: FOV ≤ 30°.

[0015] Furthermore, the operating temperature of the super-high-resolution hybrid telephoto camera lens meets the following requirements: -40℃ to 85℃.

[0016] This invention also provides a camera module, including the hybrid telephoto lens described above.

[0017] This invention also provides an electronic device, including the camera module described above.

[0018] The beneficial effects of this invention are as follows: A four-element imaging lens group structure consisting of a spherical lens, a metasurface lens, and two aspherical negative lenses, combined with prisms in the steering lens group for optical path folding, successfully combines the planar ultra-thin characteristics of the metasurface lens with the efficient aberration balancing capability of the aspherical lens. Compared to traditional pure refractive telephoto lenses of the same focal length and aperture specifications, this embodiment significantly reduces the number of lenses required for the imaging lens group, greatly compresses the axial physical length of the imaging lens group, and simultaneously achieves large aperture light transmission capability and low distortion across the entire field of view, effectively achieving the goal of miniaturization and thinning of telephoto camera lenses. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of the super-high-resolution hybrid telephoto lens provided in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the visible light MTF of the superconducting hybrid telephoto lens provided in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the visible light diffusion pattern of the superconducting hybrid telephoto lens provided in Embodiment 1 of the present invention. Figure 4 This is a schematic diagram of distortion in the hybrid telephoto lens provided in Embodiment 1 of the present invention; Figure 5 This is a schematic diagram of the structure of the super-high-resolution hybrid telephoto lens provided in Embodiment 2 of the present invention; Figure 6 This is a schematic diagram of the visible light MTF of the superconducting hybrid telephoto lens provided in Embodiment 2 of the present invention; Figure 7 This is a schematic diagram of the visible light diffusion pattern of the superconducting telephoto lens provided in Embodiment 2 of the present invention; Figure 8 This is a distortion diagram of the hybrid telephoto lens provided in Embodiment 2 of the present invention; Figure 9 This is a schematic diagram of the nanopillar arrangement of a metasurface lens provided in an embodiment of the present invention; Figure 10 This is a schematic diagram of the metasurface layer nanopillar structure of the metasurface lens provided in an embodiment of the present invention; Figure 11 A schematic diagram showing the relationship between the transmittance and phase of the metasurface lens nanopillar and the nanopillar diameter, as provided in an embodiment of the present invention. Figure 12 This is a schematic diagram of the metasurface layer structure of the metasurface lens provided in Embodiment 1 of the present invention; Figure 13 This is a schematic diagram of the metasurface layer structure of the metasurface lens provided in Embodiment 2 of the present invention.

[0021] Explanation of the markings in the image: 1. Imaging lens group; 10. Aperture stop; 11. First lens; 12. Second lens; 13. Third lens; 14. Fourth lens; 4. Filter; 2. Turning lens group; 21. Prism; 3. Imaging plane. Detailed Implementation

[0022] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] For ease of understanding, some of the technical terms involved in the embodiments of this invention will be explained and described below.

[0024] The optical axis is the direction in which light rays travel through an optical system, with the principal ray serving as a reference for the central field of view. In other words, the optical axis is a ray that passes perpendicularly through the center of an ideal lens. When light rays parallel to the optical axis enter a convex lens, an ideal convex lens should cause all the light rays to converge at a single point behind the lens; this point is the focal point.

[0025] Focal length, also known as focal length, is a measure of the convergence or divergence of light in an optical system. It refers to the distance from the optical center of a lens to the focal point when a distant object is projected into a sharp image on the focal plane. The optical center is the point on the lens where the direction of light propagation remains unchanged regardless of the direction of light passing through it. For fixed-focus lenses, the position of their optical center is fixed, therefore the focal length is fixed. For zoom lenses, changes in the optical center result in changes in the focal length, therefore the focal length can be adjusted.

[0026] The aperture is a device used to control the amount of light passing through the lens and entering the sensor inside the camera body; it is usually located inside the lens.

[0027] The aperture f-number is a relative value derived from the lens's focal length divided by its light-gathering diameter. A smaller f-number allows more light to enter the lens within the same unit of time. Conversely, a smaller aperture with a larger f-number results in a greater depth of field.

[0028] Optical power is equal to the difference between the image-side convergence and the object-side convergence of the light beam. It characterizes the ability of an optical system to deflect light rays. When the refractive index of air is approximately assumed to be 1, optical power is generally expressed as the reciprocal of the image-side focal length.

[0029] Optical power characterizes the ability of an optical system to refract an incident parallel beam of light. The higher the optical power value, the more pronounced the refraction of the parallel beam. When the optical power is greater than zero, the refraction is converging; when the optical power is less than zero, the refraction is diverging; when the optical power is equal to zero, it is plane refraction, in which case the axial parallel beam remains axially parallel after refraction, and no refraction occurs.

[0030] Total track length (TTL) refers to the total length from the lens head to the imaging plane, and is the main factor that determines the camera height.

[0031] The Abbe number, also known as the dispersion coefficient, is the ratio of the difference in refractive index of an optical material at different wavelengths, representing the degree of dispersion of the material.

[0032] The field of view (FOV) in optical instruments is the angle between the two edges of the lens, representing the maximum range through which the image of the target object can pass through the lens. The size of the FOV determines the field of view of the optical instrument; a larger FOV results in a wider field of view but a lower optical magnification.

[0033] The object side and the image side are defined by the lens. The side where the subject is located is called the object side, and the surface of the lens closest to the object side can be called the object side surface. The side where the image of the subject is located is called the image side, and the surface of the lens closest to the image side can be called the image side surface.

[0034] An aperture stop is an edge, frame, or specially designed perforated barrier in an optical assembly used to limit the size of an imaging beam or a unit of imaging space.

[0035] Distortion, also known as image distortion, refers to the degree of distortion in the image formed by an optical system relative to the object itself. Distortion occurs due to the spherical aberration of the aperture. The height of the intersection point between the principal ray from different fields of view and the Gaussian image plane is not equal to the ideal image height; this difference is the distortion. Therefore, distortion only changes the imaging position of an off-axis object point on the ideal plane, causing a distortion in the image shape, but it does not affect the image's sharpness.

[0036] Existing hybrid telephoto lenses, as a key component of camera systems, effectively compensate for the shortcomings in imaging capabilities of devices such as mobile phones and drones, becoming one of the core technologies for improving the camera photography experience and product competitiveness. Under the current technological system, the realization of hybrid telephoto lenses mainly relies on optical structure design and the integration of optical components. However, due to the hardware constraints of cameras in mobile phones, drones, and other devices, they face multiple challenges in achieving structural simplicity and miniaturization.

[0037] This invention introduces metasurface technology. A metasurface is an artificial planar material composed of subwavelength structural units, capable of modulating the phase of light. Metasurface lenses can be fabricated on very thin planes, offering new possibilities for further improving the performance of optical systems and shortening the overall lens length within limited space. Therefore, how to effectively apply metasurface technology to the optical lenses of devices such as mobile phones and drones to solve the problems of small size, low chromatic aberration, and high imaging performance remains an urgent issue to be addressed.

[0038] This invention combines the optical properties of traditional optical materials with those of metasurfaces, applying a hybrid refracto-metasurface system to applications requiring ultra-thinness, miniaturization, and high image quality, thus possessing broad application potential. Therefore, the following embodiments of this invention aim to effectively apply metasurface technology to mobile phone cameras to achieve the goals of ultra-thin structure, miniaturization, and high image quality.

[0039] Please see Figure 1 and Figure 5 This invention provides a hybrid telephoto lens, including an imaging lens group 1 and a steering lens group 2 arranged along the optical axis from the object plane to the image plane; the imaging lens group 1 includes a first lens 11, a second lens 12, a third lens 13 and a fourth lens 14 arranged along the optical axis from the object plane to the image plane; the steering lens group 2 includes at least one prism 21. The first lens 11 is a spherical lens with positive optical power; the second lens 12 is a metasurface lens with positive optical power; the third lens 13 is an aspherical lens with negative optical power; and the fourth lens 14 is an aspherical lens with negative optical power.

[0040] In this embodiment, the imaging lens group 1 is the core optical component of the lens, used to converge light from the object (object surface) and form a high-quality optical image. The imaging lens group 1 consists of only four optical lenses with specific optical power and surface shape, arranged sequentially along the optical axis as follows: first lens 11, second lens 12, third lens 13, and fourth lens 14. This four-lens configuration is a relatively streamlined design in traditional telephoto lenses, which helps to shorten the axial dimension of the lens and reduce the overall weight. The steering lens group 2 is located behind the imaging lens group 1, i.e., on the side closer to the image plane, and contains at least one prism 21 as an optical path deflection element. This prism 21 uses its internal reflective surface (total internal reflection surface or coated reflective surface) to deflect the converged light beam emitted from the imaging lens group 1 at least once or multiple times, thereby folding the optical path that originally extended in one direction (such as the thickness direction of the device) to another direction (such as the length direction of the device). This provides sufficient optical back focal length space for the telephoto lens without increasing the thickness of the device, thus achieving both a thin and light device and telephoto functionality.

[0041] In this embodiment, the turning lens group 2 may include one to three prisms 21 to achieve at least one to five turnings of light; preferably, it includes only one prism 21, which can reduce unnecessary reflection loss, reduce the difficulty of processing and assembly, and better balance optical performance and manufacturing cost while completing optical path folding and compressing lens thickness.

[0042] More specifically, firstly, the first lens 11 is configured as a spherical lens with positive optical power, meaning that the first lens 11 has the ability to converge light, effectively collecting the incident light beam from the subject and guiding the light into the subsequent optical path at a relatively gentle angle. This facilitates the system achieving the required optical power distribution with a shorter axial distance. Secondly, the second lens 12 is configured as a metasurface lens with positive optical power. The metasurface lens has an array of subwavelength microstructures arranged on its planar substrate to control the phase of light waves. Unlike traditional refractive lenses that rely on surface thickness to achieve optical power, the physical thickness of the metasurface lens depends only on the substrate thickness. It can achieve beam converging functionality equivalent to a traditional curved positive lens within an extremely thin dimension. Placing the metasurface lens as the second lens 12 at the front of the optical path allows for effective convergence of the light beam collected by the first lens 11 within a very short axial space, thereby significantly compressing the axial length required for the subsequent optical path. Finally, both the third lens 13 and the fourth lens 14 are configured as aspherical lenses with negative optical power. The primary purpose of using two aspherical lenses with negative optical power consecutively is to effectively correct image distortion that is prone to occur under large aperture conditions within a compact optical path structure, ensuring geometrical fidelity of the image across the entire field of view. The surface curvature of the aspherical lens changes continuously from the center to the edge, providing more flexible light control than spherical lenses within the constraints of limited lens thickness and number. This allows the four-element lens to be adapted to smaller aperture numbers (i.e., large apertures), ensuring that off-axis rays also converge accurately on the image plane, achieving a clear and low-distortion imaging effect with the same edge and center field of view. At the same time, the combination of positive and negative optical power lenses also helps to correct fundamental aberrations such as chromatic aberration while maintaining a short overall length.

[0043] Based on this, this embodiment features a four-element imaging lens group 1 consisting of one spherical lens, one metasurface lens, and two aspherical negative lenses. Combined with the prism 21 of the turning lens group 2 for optical path folding, it successfully combines the planar ultra-thin characteristics of the metasurface lens with the efficient aberration balancing capability of the aspherical lens. Compared to traditional pure refractive telephoto lenses of the same focal length and aperture specifications, this embodiment significantly reduces the number of lenses required for the imaging lens group 1, greatly compresses the axial physical length of the imaging lens group 1, and simultaneously achieves large aperture light transmission capability and low distortion across the entire field of view, effectively achieving the goal of miniaturization and thinning of telephoto camera lenses.

[0044] In one embodiment, the super-hybrid telephoto lens satisfies: 6≤(Fno×Imgh) / L≤13; 110≤(f×FOV) / L≤170; where Fno is the aperture number, Imgh is the diagonal size of the imaging target surface, L is the total length of the imaging lens group 1, f is the focal length, and FOV is the diagonal field of view.

[0045] In this embodiment, there is a specific correlation between the optical performance and structural size of the hybrid telephoto lens. By limiting the above-mentioned conditional formula, it can be ensured that the lens can achieve a better balance between miniaturization, large aperture and high image quality.

[0046] First, the hybrid telephoto lens of this embodiment satisfies the condition formula 6 ≤ (Fno × Imgh) / L ≤ 13. In this condition formula, Fno represents the aperture number of the lens, which is the ratio of the lens focal length to the effective aperture, reflecting the lens's light transmission capability; the smaller the value of Fno, the larger the aperture, and the more light energy can enter the lens under the same lighting conditions. Imgh is the diagonal size of the imaging target surface, used to characterize the size specification of the imaging target surface that the lens can cover. L represents the total length of the imaging lens group 1, which is precisely defined as the physical distance between the optical axis center position of the first lens 11 on the object side and the optical axis center position of the fourth lens 14 on the image side. The condition formula (Fno × Imgh) / L of this embodiment establishes a comprehensive performance index to correlate the lens's aperture capability (reflected by the product of Fno and Imgh) with the lens's axial dimension (L). When this ratio is between 6 and 13, it indicates that the visible light camera lens, while possessing a large imaging target area (larger image size) and a large aperture (smaller f-no), can still maintain a relatively short physical length for the imaging lens group 1. If the ratio is below the lower limit of 6, the total length of the lens may be too long for the given image area and aperture requirements, failing to fully realize the advantages of miniaturization; conversely, if it is above the upper limit of 13, the aperture number or image area may be excessively sacrificed in pursuit of an extremely small size, resulting in insufficient light transmission or inability to adapt to large-area image sensors.

[0047] Secondly, the hybrid telephoto lens of this embodiment also satisfies the condition 110 ≤ (f × FOV) / L ≤ 170. In this condition, f represents the effective focal length of the entire hybrid telephoto lens, which determines the lens's field of view and magnification. FOV represents the diagonal field of view of the lens, used to describe the maximum spatial angle range that the lens can clearly image. The condition (f × FOV) / L is used to characterize the combined parameters of the lens's telephoto ratio and compactness. The product of focal length f and field of view FOV reflects the combined effect of the object space range covered by the lens and its telephoto capability (ability to bring distant objects closer). Dividing the product of focal length f and field of view FOV by the total physical length L of the imaging lens group 1 yields a ratio that quantifies the telephoto and field of view capabilities that the lens can achieve per unit structural length. When this ratio is within the range of 110 to 170, the lens of the present invention has a relatively long focal length (e.g., f≥18mm) to achieve telephoto functionality, and with a corresponding field of view, the axial dimension L of the imaging lens group 1 is effectively compressed, balancing high structural compactness and optical integration efficiency. For example, in Embodiment 1 below, this ratio is 117.52; in Embodiment 2, the ratio is 163.08, both falling within the range of 110 to 170. This range ensures that the lens achieves significant telephoto characteristics without sacrificing overall length control, thus truly realizing the design goal of a miniaturized telephoto lens.

[0048] Based on this, the embodiments of the present invention, by satisfying the above two conditional formulas, establish a clear and quantifiable optimal matching relationship between the physical size, light transmission capability, imaging range, and focal length of the hybrid telephoto lens. This ensures that the lens achieves a miniaturized overall optical length while possessing the characteristics of a large aperture (smaller Fno) and a high imaging range coverage (a balance between a large image height and FOV), thereby providing bright, clear, and appropriately angled telephoto images in various shooting environments.

[0049] In one embodiment, the object side of the first lens 11 is convex near the optical axis, and the image side is concave near the optical axis; the image side of the second lens 12 has microstructures arranged; the object side of the third lens 13 is convex near the optical axis, and the image side is concave near the optical axis; the object side of the fourth lens 14 is convex / concave near the optical axis, and the image side is concave near the optical axis.

[0050] In this embodiment, the first lens 11 with positive optical power has a surface shape defined as a convex surface near the optical axis on the object side and a concave surface near the optical axis on the image side. This convex-concave meniscus structure is beneficial for collecting light rays from different field angles on the object side and smoothly guiding them into the subsequent optical system. It helps to achieve the required optical power within a limited axial distance and has a positive effect on the overall length of the control system. It can also effectively reduce the aberrations, especially spherical aberration and coma, generated by large field angle light rays on the surface of the first lens 11.

[0051] In this embodiment, the second lens 12, which has positive optical power, serves as a metasurface lens. The metasurface lens comprises a substrate and microstructures. Each microstructure has a specific shape, size, and arrangement to achieve precise control over the phase, amplitude, or polarization state of the incident light wave. Through the design of the microstructures, the metasurface lens can achieve optical performance comparable to or even superior to that of traditional lenses while maintaining a slim and lightweight design, such as high transmittance, low chromatic aberration, and low distortion. The period of the microstructure of the second lens ranges from 250 to 400 nm, with an optimal period of 300 nm in this embodiment; the height of the microstructure ranges from 600 to 2000 nm, with an optimal height of 1200 nm in this embodiment; the diameter of the microstructure covers 90 to 200 nm and is arranged in square, hexagonal, or other shapes; the substrate material is a visible light low-refractive-index glass material, such as D263TECO or BF33, and the main part of the microstructure is a visible light high-refractive-index material, such as silicon nitride or titanium oxide; the microstructure may also include visible light low-refractive-index materials for protection, such as silicon oxide; through the coordination of materials and the optical power of each lens, the imaging quality of the imaging lens is improved, and the size of the system is reduced.

[0052] In this embodiment, the third lens 13 with negative optical power is defined as having a convex surface near the optical axis on the object side and a concave surface near the optical axis on the image side. This meniscus-shaped negative lens shape helps to achieve the required negative optical power with a relatively gentle surface curvature, thereby reducing the deflection angle of edge rays under large aperture conditions. It has a direct effect on correcting distortion under large field of view, and its aspherical surface shape further enhances this correction capability.

[0053] In this embodiment, the fourth lens 14, which has negative optical power, has its image-side surface defined as concave near the optical axis, while its object-side surface can be either convex or concave near the optical axis. This design flexibility provides optimization freedom for optical design. Regardless of the object-side surface shape, the concave shape of its image-side surface is beneficial for matching the emitted beam from the front lens. As the last optical surface of the imaging lens group 1, it projects the fully corrected beam at an appropriate angle to the subsequent steering lens group 2, further optimizing factors affecting imaging uniformity such as distortion and field curvature under a compact overall length constraint.

[0054] Based on this, the specific surface orientation and structural features of each lens are defined. The meniscus shape of the first lens 11 facilitates the smooth collection of light; the planar substrate and image plane microstructure arrangement of the second lens 12 achieve ultra-thin beam convergence; the meniscus negative lens shape of the third lens 13, combined with the aspherical design, effectively corrects distortion; and the flexible surface shape and concave image side features of the fourth lens 14 provide the final structural guarantee for achieving small distortion across the entire field of view within a compact overall length. The combination of these surface features is the key geometric basis for achieving the large aperture, small distortion, and short overall length of the super-hybrid telephoto camera lens of this invention.

[0055] In one embodiment, the steering lens assembly 2 includes a prism 21.

[0056] In this embodiment, the prism 21, as an independent optical element, is disposed on the image side of the imaging lens group 1. The converging light beam from the imaging lens group 1 first enters the prism 21, and after undergoing at least one reflection based on total internal reflection or a reflective coating, the propagation direction of the light beam is changed. This deflection design can transform the light path, which originally propagates along the thickness direction of the device (such as the Z-axis direction of a mobile phone), into a path that propagates along the length or width direction of the device (such as the X-axis or Y-axis direction of a mobile phone). This embodiment, employing only a single prism 21, achieves optical path folding and compresses the device thickness while minimizing the number of optical elements.

[0057] In one embodiment, the first lens 11 and the prism 21 are both made of visible light glass, and the third lens 13 and the fourth lens 14 are both made of visible light resin.

[0058] In this embodiment, the choice of materials for the optical lenses has a crucial impact on their performance, cost, and reliability. Specifically, the first lens 11, located at the foremost point of the object and in direct contact with the external environment, and the prism 21 used to change the optical path, are both made of visible light glass. The rigidity and thermal stability of the glass material ensure that both maintain a precise reflection angle at different operating temperatures, guaranteeing the pointing stability of the optical path. Since the third lens 13 and the fourth lens 14 are both aspherical, they are made of visible light resin, which allows for low-cost and high-efficiency mass production of aspherical lenses with complex surface shapes. Furthermore, the substrate of the second lens 12 is made of visible light glass to ensure flatness and stability during the micro / nano structure transfer process, while the microstructure on its surface is made of a high-refractive-index dielectric material, such as silicon nitride (Si3N4) or titanium oxide (TiO2).

[0059] In one embodiment, the hybrid telephoto lens further includes an aperture stop 10 located between the second lens 12 and the third lens 13.

[0060] In this embodiment, the aperture stop 10 is a key component in the optical system used to limit the size of the imaging beam aperture, directly affecting the aperture number Fno of the lens. The hybrid telephoto lens provided in this embodiment of the invention also includes an aperture stop 10, which is positioned in the optical path between the second lens 12 and the third lens 13. The placement of the aperture stop 10 in this position is closely related to the overall structural design of the hybrid telephoto lens. The second lens 12 is a metasurface lens with positive optical power, effectively converging the light beam within an extremely thin planar structure, thus compressing the beam aperture to a certain extent. Positioning the aperture stop 10 immediately after the second lens 12 and before the third lens 13 allows for precise limitation of the light transmission in a relatively small beam aperture area with a smaller physical aperture, thereby effectively defining the system's large aperture specification. Simultaneously, this position is located in the slightly forward-central region of the imaging lens group 1, which is beneficial for symmetrically limiting on-axis and off-axis beams, achieving a large aperture design while ensuring uniformity of the entire field of view imaging, and avoiding excessive vignetting or image quality degradation at the edges of the field of view.

[0061] In one embodiment, the superconducting telephoto lens further includes a filter 4 located between the prism 21 and the image plane.

[0062] In this embodiment, the main function of filter 4 is to selectively transmit visible light while effectively absorbing near-infrared light. Processing light through filter 4 is a crucial step in ensuring accurate color reproduction. The object-side and image-side surfaces of filter 4 are typically planar to avoid introducing additional optical power or aberrations. Placing filter 4 behind prism 21 and in front of the image plane utilizes the relatively spacious area between prism 21 and the image plane, facilitating installation. Furthermore, its planar structure prevents additional complex aberrations from affecting the converging beam after it has been deflected by prism 21.

[0063] In one embodiment, the focal length f of the hybrid telephoto lens satisfies: f ≥ 18 mm.

[0064] In this embodiment, the focal length f of the lens is the core parameter that determines its angle of view and magnification. The longer the focal length of the lens, the narrower its angle of view, and the stronger its telephoto capability. The focal length f of the lens of this invention is 18mm or longer (for example, 28.02mm and 21.02mm in the following embodiments one and two). When used in conjunction with a wide-angle main camera, this telephoto lens can achieve long-distance shooting.

[0065] In one embodiment, the aperture number Fno of the hybrid telephoto lens satisfies: 2.8 ≤ Fno ≤ 4.0.

[0066] In this embodiment, the aperture number Fno is the ratio of the lens's effective aperture to its focal length, a key indicator of the lens's light-gathering capability. A smaller Fno value indicates a larger aperture, meaning more light energy reaches the image plane per unit time. The aperture number Fno of this invention falls within the range of 2.8 to 4.0, allowing the telephoto lens to achieve a large effective aperture while maintaining a compact structure. This ensures excellent imaging capabilities even in low-light environments, capturing images with less noise and clearer details.

[0067] In one embodiment, the field of view (FOV) of the super-hybrid telephoto lens satisfies: FOV ≤ 30°.

[0068] In this embodiment, the field of view (FOV) describes the maximum spatial range that the lens can observe, and it is directly related to the lens's focal length and the size of the imaging target. With a fixed imaging target size, the longer the lens's focal length, the narrower its FOV. Therefore, the characteristic of FOV ≤ 30° corresponds to the aforementioned focal length limitation of f ≥ 18mm. For example, in Embodiment 1 below, when the focal length is 28.2mm, the corresponding FOV is 18.1°; in Embodiment 2 below, when the focal length is 21.1mm, the corresponding FOV is 24.0°, both satisfying the FOV ≤ 30° condition. By limiting the lens's diagonal FOV to 30° or less and combining it with a long focal length, the lens can effectively eliminate interference from the surrounding cluttered environment, achieving the optical effects of magnifying details and compressing the sense of space.

[0069] In one embodiment, the hybrid telephoto lens operates at a temperature range of -40°C to 85°C. The hybrid telephoto lens maintains stable imaging performance even within this extreme operating temperature range of -40°C to 85°C.

[0070] Based on the above solutions, the present invention provides the following various feasible embodiments of lens architecture and component parameters.

[0071] Example 1: like Figure 1 As shown, the super-high-resolution hybrid telephoto lens provided in Embodiment 1 of the present invention includes a first lens 11, a second lens 12, an aperture 10, a third lens 13, a fourth lens 14, and a prism 21 arranged along the optical axis from the object plane to the image plane.

[0072] The first lens 11 is a spherical lens with positive optical power. Its object side is convex near the optical axis, and its image side is concave near the optical axis. Its material is glass.

[0073] The second lens 12 is a metasurface lens with positive optical power, and its image side has a microstructure arrangement. Its material is glass.

[0074] Among them, the third lens 13 is an aspherical lens with negative optical power. Its object side is convex near the optical axis and its image side is concave near the optical axis. Its material is resin.

[0075] Among them, the fourth lens 14 is an aspherical lens with negative optical power. Its object side is convex near the optical axis and its image side is concave near the optical axis. Its material is resin.

[0076] The prism 21 can be a secondary reflection prism, and the material of the prism 21 is glass.

[0077] like Figure 1 As shown, the incident light passes sequentially through the first lens 11, the second lens 12, the aperture 10, the third lens 13, the fourth lens 14, and the prism 21, and converges on the imaging surface 3.

[0078] For example, Table 1 details the specific optical data parameters of each lens in the hybrid telephoto lens provided in Embodiment 1 of the present invention, using a feasible implementation method. The optical data parameters in Table 1 correspond to... Figure 1 The image shows a hybrid telephoto lens with refractive index and supersonic extension at room temperature.

[0079] Table 1: In Table 1, the surface numbers are assigned according to the surface order of each lens. For example, surface number 1 represents the object side of the first lens 11, surface number 2 represents the image side of the first lens 11, and so on.

[0080] Wherein, Standard represents the standard surface; EVEN ASPHERE represents the aspherical surface; Binary2 represents the binary surface; Infinity represents that the surface is planar; the radius of curvature represents the degree of curvature of the lens surface, with a positive value indicating that the lens surface bends towards the image plane and a negative value indicating that the lens surface bends towards the object plane; the spacing represents the central axial distance from the current surface to the next surface; the refractive index and Abbe number are used to describe the material of each lens, and the focal length represents the effective focal length of each lens; the unit is millimeters (mm).

[0081] The surface shape of an aspherical lens satisfies the following equation: ; Where z is the distance from the vertex of the extended aspherical surface along the optical axis, r is the height from the optical axis, c is the curvature 1 / R, R is the radius of curvature at the vertex of the lens; k is the conic coefficient, N is the highest term number, and a i For aspherical higher-order terms, the coefficients are given.

[0082] For example, Table 2 details the conic coefficient k and higher-order coefficient a of the aspherical lens surface in this embodiment, using a feasible implementation method. i .

[0083] Table 2: In Table 2, the value of coefficient a2 with face number 6 is 8.04E-03, and so on.

[0084] The phase of the second lens 12 (i.e., metasurface lens) in this embodiment of the invention is increased by polynomial expansion: Where N is the number of polynomial coefficients in the series, and A i It is the square coefficient of ρ, where ρ is the normalized radial aperture coordinate, and M is the diffraction order.

[0085] For example, Table 3 details the binary surface coefficients of the metasurface lens in this embodiment with a feasible implementation method.

[0086] Table 3: Where R1 is the normalized radius of the binary surface; A1 to A10 are the binary surface coefficients of the metasurface lens.

[0087] In this case, the metasurface layer of the metasurface lens is composed of periodically arranged nanopillars, such as... Figure 9 As shown, the arrangement is hexagonal, and the period of the nanopillars is p = 300 nm. Figure 10 As shown, the nanopillars have a height h1 = 1200 nm and a refractive index n = 2.3. A protective layer exists outside the nanopillars, with a height h2 = 3400 nm and a refractive index n = 1.52. The nanopillar diameters range from 100 nm to 200 nm. The relationships between the nanopillar transmittance and phase and the nanopillar diameter are shown below. Figure 11 As shown in (a) and (b) in the figure. The diameter of the nanopillars at different positions of the metasurface lens can be obtained based on the phase distribution formula of the metasurface lens, such as... Figure 12 As shown.

[0088] Based on the lens architecture and component parameters of Embodiment 1, the aperture number, image height, and total length of the imaging lens group 1 in this embodiment satisfy (Fno×Imgh) / L=6.75; the total length of the imaging lens group 1, field of view, and focal length satisfy (f×FOV) / L=117.52; the hybrid telephoto lens provided in this embodiment operates in the wavelength range of 430~650nm, has an aperture of 3.23, a focal length of 28.02mm, a maximum field of view of 18.06°, and a corresponding image height of 9.0mm, meeting the usage requirements of a telephoto lens.

[0089] Figure 2 This is a schematic diagram of the modulation transfer function (MTF) of a visible telephoto camera lens provided in an embodiment of the present invention. The hybrid telephoto camera lens of the present invention has an MTF value ≥ 0.4 in the entire field of view at 150 lp / mm, which can be matched with conventional chips and meet the requirements of high-resolution imaging.

[0090] Figure 3 This is a schematic diagram of the blur pattern of a visible telephoto lens provided in an embodiment of the present invention. The visible telephoto lens of the present invention has a relatively concentrated blur pattern across the entire wavelength band, with an RMS Radius ≤ 1.5 μm across the entire field of view, and is uniformly distributed, which can meet the requirements of high-resolution imaging.

[0091] Figure 4 This is a distortion diagram of a visible telephoto lens provided in an embodiment of the present invention. The distortion diagram is used to represent the distortion values ​​corresponding to different fields of view, such as... Figure 4 As shown, the visible telephoto lens provided in this embodiment of the invention has a distortion of less than 0.3% across the entire field of view in the working wavelength band, and the overall distortion is small.

[0092] Example 2: like Figure 5 As shown, the super-high-resolution hybrid telephoto lens provided in Embodiment 2 of the present invention includes a first lens 11, a second lens 12, an aperture 10, a third lens 13, a fourth lens 14, a prism 21, and a filter 4 arranged along the optical axis from the object plane to the image plane.

[0093] The first lens 11 is a spherical lens with positive optical power. Its object side is convex near the optical axis, and its image side is concave near the optical axis. Its material is glass.

[0094] The second lens 12 is a metasurface lens with positive optical power, and its image side has a microstructure arrangement. Its material is glass.

[0095] Among them, the third lens 13 is an aspherical lens with negative optical power. Its object side is convex near the optical axis and its image side is concave near the optical axis. Its material is resin.

[0096] Among them, the fourth lens 14 is an aspherical lens with negative optical power. Its object side is concave near the optical axis, and its image side is concave near the optical axis. Its material is resin.

[0097] The prism 21 can be a four-fold reflection prism, and the material of the prism 21 is glass.

[0098] The material of filter 4 is glass.

[0099] like Figure 5As shown, the incident light passes sequentially through the first lens 11, the second lens 12, the aperture 10, the third lens 13, the fourth lens 14, the prism 21, and the filter 4, and converges on the imaging surface 3.

[0100] For example, Table 4 details the specific optical data parameters of each lens in the hybrid telephoto lens provided in Embodiment 2 of the present invention, using a feasible implementation method. The optical data parameters in Table 4 correspond to... Figure 5 The image shows a hybrid telephoto lens with refractive index and supersonic extension at room temperature.

[0101] Table 4: In Table 4, the surface numbers are assigned according to the surface order of each lens. For example, surface number 1 represents the object side of the first lens 11, surface number 2 represents the image side of the first lens 11, and so on.

[0102] Wherein, Standard represents the standard surface; EVEN ASPHERE represents the aspherical surface; Binary2 represents the binary surface; Infinity represents that the surface is planar; the radius of curvature represents the degree of curvature of the lens surface, with a positive value indicating that the lens surface bends towards the image plane and a negative value indicating that the lens surface bends towards the object plane; the spacing represents the central axial distance from the current surface to the next surface; the refractive index and Abbe number are used to describe the material of each lens, and the focal length represents the effective focal length of each lens; the unit is millimeters (mm).

[0103] The surface shape of an aspherical lens satisfies the following equation: ; Where z is the distance from the vertex of the extended aspherical surface along the optical axis, r is the height from the optical axis, c is the curvature 1 / R, R is the radius of curvature at the vertex of the lens; k is the conic coefficient, N is the highest term number, and a i For aspherical higher-order terms, the coefficients are given.

[0104] For example, Table 5 details the conic coefficient k and higher-order coefficient a of the aspherical lens surface in this embodiment, using a feasible implementation method. i .

[0105] Table 5: In Table 5, the value of coefficient a2 with face number 6 is 1.09E+00, and so on.

[0106] The phase of the second lens 12 (i.e., metasurface lens) in this embodiment of the invention is increased by polynomial expansion: Where N is the number of polynomial coefficients in the series, and Ai It is the square coefficient of ρ, where ρ is the normalized radial aperture coordinate, and M is the diffraction order.

[0107] For example, Table 6 details the binary surface coefficients of the metasurface lens in this embodiment with a feasible implementation method.

[0108] Table 6: Where R1 is the normalized radius of the binary surface; A1 to A10 are the binary surface coefficients of the metasurface lens.

[0109] In this case, the metasurface layer of the metasurface lens is composed of periodically arranged nanopillars, such as... Figure 9 As shown, the arrangement is hexagonal, and the period of the nanopillars is p = 300 nm. Figure 10 As shown, the nanopillars have a height h1 = 1200 nm and a refractive index n = 2.3. A protective layer exists outside the nanopillars, with a height h2 = 3400 nm and a refractive index n = 1.52. The nanopillar diameters range from 100 nm to 200 nm. The relationships between the nanopillar transmittance and phase and the nanopillar diameter are shown below. Figure 11 As shown in (a) and (b) in the figure. The diameter of the nanopillars at different positions of the metasurface lens can be obtained based on the phase distribution formula of the metasurface lens, such as... Figure 13 As shown. It should be noted that the diameter of the nanopillars in Examples 1 and 2 can be selected within the above range according to the desired target phase and nanopillar transmittance, thereby forming different phase distributions to adapt to different optical parameter requirements.

[0110] Based on the lens architecture and component parameters of Embodiment 2, the aperture number, image height, and total length of the imaging lens group 1 in this embodiment satisfy (Fno×Imgh) / L=11.13; the total length of the imaging lens group 1, field of view, and focal length satisfy (f×FOV) / L=163.08; the hybrid telephoto lens provided in this embodiment operates in the wavelength range of 430~650nm, has an aperture of 3.82, a focal length of 21.02mm, a maximum field of view of 23.96°, and a corresponding image height of 9.0mm, meeting the usage requirements of a telephoto lens.

[0111] Figure 6 This is a schematic diagram of the modulation transfer function (MTF) of a visible telephoto camera lens provided in an embodiment of the present invention. The hybrid telephoto camera lens of the present invention has an MTF value ≥ 0.4 in the entire field of view at 150 lp / mm, which can be matched with conventional chips and meet the requirements of high-resolution imaging.

[0112] Figure 7This is a schematic diagram of the blur pattern of a visible telephoto lens provided in an embodiment of the present invention. The visible telephoto lens of the present invention has a relatively concentrated blur pattern across the entire wavelength band, with an RMS Radius ≤ 2.5 μm across the entire field of view, and is uniformly distributed, which can meet the requirements of high-resolution imaging.

[0113] Figure 8 This is a distortion diagram of a visible telephoto lens provided in an embodiment of the present invention. The distortion diagram is used to represent the distortion values ​​corresponding to different fields of view, such as... Figure 8 As shown, the visible telephoto lens provided in this embodiment of the invention has a distortion of less than 0.5% across the entire field of view in the working wavelength band, and the overall distortion is small.

[0114] In summary, the lens architecture and component parameters provided in Embodiment 1 and Embodiment 2 satisfy the relationships shown in Table 7 below.

[0115] Table 7: In summary, this invention comprises a four-element imaging lens group 1 consisting of a spherical lens, a metasurface lens, and two aspherical negative lenses. Combined with the prism 21 of the steering lens group 2 for optical path folding, it successfully combines the planar ultra-thin characteristics of the metasurface lens with the efficient aberration balancing capability of the aspherical lens. Compared to traditional pure refractive telephoto lenses of the same focal length and aperture specifications, this embodiment significantly reduces the number of lenses required for the imaging lens group 1, substantially compresses the axial physical length of the imaging lens group 1, and simultaneously achieves large aperture light transmission capability and low distortion across the entire field of view, effectively achieving the goal of miniaturization and thinning of telephoto camera lenses.

[0116] This invention also provides a camera module, including the hybrid telephoto lens described above. Because the camera module uses the aforementioned hybrid telephoto lens, it also possesses advantages corresponding to optical lenses, such as large aperture, low distortion, fewer lens elements, miniaturized lens, and thinner and lighter design.

[0117] This invention also provides an electronic device, including the camera module described above. The electronic device can be an electronic device with video or photographic capabilities, such as a mobile phone, tablet computer, laptop, camcorder, video recorder, camera, intelligent robot, or other devices with photographic or video recording capabilities.

[0118] Finally, it should be noted that the above descriptions are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions within the technical scope disclosed in the present invention should be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A hybrid telephoto lens, characterized in that, It includes an imaging lens group and a steering lens group arranged along the optical axis from the object plane to the image plane; the imaging lens group includes a first lens, a second lens, a third lens and a fourth lens arranged along the optical axis from the object plane to the image plane; the steering lens group includes at least one prism; The first lens is a spherical lens with positive optical power; The second lens is a metasurface lens with positive optical power; The third lens is an aspherical lens with negative optical power; The fourth lens is an aspherical lens with negative optical power.

2. The hybrid telephoto lens according to claim 1, characterized in that, The aforementioned hybrid telephoto lens satisfies: 6≤(Fno×Imgh) / L≤13; 110≤(f×FOV) / L≤170; Where Fno is the aperture number, Imgh is the diagonal size of the imaging target surface, L is the total length of the imaging lens group, f is the focal length, and FOV is the diagonal field of view.

3. The hybrid telephoto lens according to claim 1, characterized in that, The object-side surface of the first lens is convex near the optical axis, and the image-side surface is concave near the optical axis. The image-side surface of the second lens has a microstructure arrangement; The object-side surface of the third lens is convex near the optical axis, and the image-side surface is concave near the optical axis. The fourth lens has a convex / concave surface near the optical axis on the object side and a concave surface near the optical axis on the image side.

4. The hybrid telephoto lens according to claim 1, characterized in that, The steering lens assembly includes a prism.

5. The hybrid telephoto lens according to claim 1, characterized in that, The first lens and the prism are both made of visible light glass, and the third lens and the fourth lens are both made of visible light resin.

6. The hybrid telephoto lens according to claim 1, characterized in that, It also includes an aperture stop, which is located between the second lens and the third lens.

7. The hybrid telephoto lens according to claim 1, characterized in that, It also includes a color filter, which is located between the prism and the image plane.

8. The hybrid telephoto lens according to any one of claims 1 to 7, characterized in that, The focal length f of the hybrid telephoto lens satisfies: f≥18mm.

9. The hybrid telephoto lens according to any one of claims 1 to 7, characterized in that, The aperture number Fno of the hybrid telephoto lens satisfies: 2.8≤Fno≤4.

0.

10. The hybrid telephoto lens according to any one of claims 1 to 7, characterized in that, The field of view (FOV) of the hybrid telephoto lens meets the following requirement: FOV ≤ 30°.

11. The hybrid telephoto lens according to any one of claims 1 to 7, characterized in that, The operating temperature of the hybrid telephoto lens meets the requirement of -40℃ to 85℃.

12. A camera module, characterized in that, Including the super-hybrid telephoto lens as described in any one of claims 1-11 above.

13. An electronic device, characterized in that, Including the camera module as described in claim 12 above.

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