An ultra-compact folded hybrid lens, a camera module and a terminal device

Abstract

The application discloses a folded hyper-hybrid small-volume lens, a camera module and a terminal device. The lens comprises a first lens, a second lens, a third lens and a fourth lens arranged along an optical axis from an object plane to an image plane; the first to third lenses are aspherical lenses, and the fourth lens is a hyperlens; the first lens has positive focal power, the object side surface thereof is a convex surface, and the image side surface thereof is a concave surface; the second lens has negative focal power, the object side surface thereof is a convex surface, and the image side surface thereof is a concave surface; the third lens has negative focal power, the object side surface thereof is a concave surface, and the image side surface thereof is a concave surface; and the fourth lens has negative focal power, the object side surface thereof is a convex surface, and the image side surface thereof has a microstructure arrangement. The application adopts the combination of three aspherical refractive lenses and one hyperlens, and introduces a pressed aspherical surface to enhance the focal power contribution ability of the fourth lens, thereby significantly reducing the number of traditional refractive lenses and reducing the axial length of the lens while ensuring the imaging definition. The lens has the advantages of small volume and high imaging.

Description

Technical Field

[0001] This invention relates to the field of optical imaging technology, and in particular to a hybrid refractive-hyper-magnification small-volume lens, camera module, and terminal device. Background Technology

[0002] In the development of wearable devices such as AR glasses, the projection engine, as one of its core components, directly impacts the user experience due to its size and weight. The projection lens, in particular, occupies a significant portion of the engine's volume. Therefore, researching simple and miniaturized projection lenses is essential.

[0003] Traditional refractive projection lenses, in order to achieve the required optical power to deflect light, must use curved lenses with a certain thickness. This design inevitably means that the lens occupies a large space along the optical axis, making it difficult to achieve ultra-thinness and lightweight design.

[0004] A metasurface is an artificial planar material composed of subwavelength structural units that can modulate the phase of light. Metalens made using metasurfaces can be fabricated on very thin planes, offering new possibilities for further improving the performance of optical systems and shortening the overall length of lenses within limited space. Therefore, how to effectively apply metasurface technology to optical lenses to achieve small size and high imaging performance remains a pressing technical challenge. Summary of the Invention

[0005] The purpose of this invention is to provide a hybrid superconducting lens, camera module, and terminal device, aiming to solve the problem of how to effectively apply metasurface technology to optical lenses to achieve small size and imaging.

[0006] To solve the above-mentioned technical problems, the objective of this invention is achieved through the following technical solution: providing a hybrid refractive-superlens small-volume lens, comprising 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 first lens, the second lens, and the third lens are aspherical lenses, and the fourth lens is a superlens; The first lens has positive optical power, its object side is convex, and its image side is concave. The second lens has negative optical power, its object side is convex, and its image side is concave. The third lens has negative optical power, and its object side is concave, as is its image side. The fourth lens has negative optical power, its object side is convex, and its image side has a microstructure arrangement.

[0007] Furthermore, the object-side surface of the fourth lens is an embossed aspherical surface.

[0008] Furthermore, the aforementioned hybrid super-folding small-volume lens satisfies: TTL / EFL≤0.8; EPD / EFL≤0.7; Wherein, TTL represents the distance from the center of the optical axis on the object side of the first lens to the image plane, EFL represents the effective focal length of the entire lens, and EPD represents the entrance pupil diameter of the lens system.

[0009] Furthermore, the TTL / MIC < 1.45; MIC represents the maximum image circle size.

[0010] Furthermore, it also includes an aperture stop located on the object side of the first lens.

[0011] Furthermore, the first lens, the second lens, and the third lens are made of plastic, and the fourth lens is made of plastic or glass.

[0012] Furthermore, the focal length f of the hybrid superconducting small-volume lens satisfies: f≥5.5mm.

[0013] Furthermore, the field of view (Fov) of the superconducting hybrid small-volume lens satisfies: Fov ≥ 25°.

[0014] Furthermore, the aperture number F of the hybrid super-refractive small-volume lens satisfies F≤1.8.

[0015] This invention also provides a camera module, including the hybrid small-volume lens described above.

[0016] This invention also provides a terminal device, including the camera module described above.

[0017] The beneficial effects of this invention are as follows: by using a combination of three aspherical refractive lenses and one superlens, the number of traditional refractive lenses is significantly reduced while ensuring image clarity, thus lowering the lens axial length. Furthermore, the introduction of imprinted aspherical surfaces further enhances the optical power contribution of the fourth lens, thereby further shortening the total lens length (TTL). Simultaneously, the aspherical characteristics help correct higher-order aberrations and improve image quality. This achieves a small size and high imaging performance. Attached Figure Description

[0018] 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.

[0019] Figure 1This is a schematic diagram of the structure of the hybrid superconducting lens provided in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the visible light MTF of a hybrid superconducting small-volume lens provided in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the visible light diffusion pattern of a hybrid superconducting small-volume lens provided in Embodiment 1 of the present invention. Figure 4 This is a schematic diagram of the structure of the hybrid superconducting lens provided in Embodiment 2 of the present invention; Figure 5 This is a schematic diagram of the MTF of visible light for a hybrid superconducting small-volume lens provided in Embodiment 2 of the present invention; Figure 6 This is a schematic diagram of the visible light diffusion pattern of the superconducting hybrid small-volume lens provided in Embodiment 2 of the present invention; Figure 7 This is a schematic diagram of the nanopillar arrangement of a metasurface lens provided in an embodiment of the present invention; Figure 8 This is a schematic diagram of the metasurface layer nanopillar structure of the metasurface lens provided in an embodiment of the present invention; Figure 9 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 10 This is a schematic diagram of the metasurface layer structure of the metasurface lens provided in Embodiment 1 of the present invention; Figure 11 This is a schematic diagram of the metasurface layer structure of the metasurface lens provided in Embodiment 2 of the present invention.

[0020] Explanation of the markings in the image: 100, Aperture stop; 200, First lens; 300, Second lens; 400, Third lens; 500, Fourth lens; 600, Imaging plane. Detailed Implementation

[0021] 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.

[0022] For ease of understanding, some of the technical terms involved in the embodiments of this invention will be explained and described below.

[0023] 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.

[0024] 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 focused into a clear 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.

[0025] 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.

[0026] 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 time frame. A larger f-number results in a shallower depth of field, blurring the background and creating an effect similar to a telephoto lens.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] Existing hybrid compact lenses, as a key component of camera systems, effectively compensate for the shortcomings of AR glasses in imaging capabilities, becoming one of the core technologies for improving camera photography experience and product competitiveness. Under the current technological system, the realization of hybrid compact lenses mainly relies on optical structure design and the integration of optical components. However, due to the hardware form constraints of AR glasses, they face multiple challenges in achieving structural simplicity and miniaturization.

[0036] This invention introduces metasurface technology, a type of artificial planar material composed of subwavelength structural units capable of modulating the phase of light. Metalenses made using metasurfaces 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 optical lenses to achieve small size and high imaging performance remains a pressing technical problem to be solved.

[0037] 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 AR glasses to achieve the goals of ultra-thin structure, miniaturization, and high image quality.

[0038] Please see Figure 1 and Figure 4This invention provides a hybrid superconducting lens, comprising a first lens 200, a second lens 300, a third lens 400, and a fourth lens 500 arranged along the optical axis from the object plane to the image plane; the first lens 200, the second lens 300, and the third lens 400 are aspherical lenses, and the fourth lens 500 is a superlens; The first lens 200 has positive optical power, its object side is convex, and its image side is concave. The second lens 300 has negative optical power, its object side is convex, and its image side is concave. The third lens 400 has negative optical power, and its object side is concave, and its image side is concave. The fourth lens 500 has negative optical power, its object side is convex, and its image side has a microstructure arrangement.

[0039] In this embodiment, the hybrid superconducting lens uses only a combination of one superlens and three refractive lenses. The first lens 200, the second lens 300, and the third lens 400 are constructed aspherical lenses, which effectively correct spherical aberration and astigmatism. The fourth lens 500 is a superlens with a subwavelength microstructure arrangement on its surface. By adjusting the geometric parameters of the microstructures (such as height, width, and period), the phase distribution of transmitted light is modulated, thereby achieving the light-converging or diverging function of a traditional curved lens.

[0040] Specifically, the first lens 200 is configured with positive optical power, its object-side surface is convex and its image-side surface is concave. This surface structure is beneficial for collecting light from the object side and initially converging it. The second lens 300 has negative optical power, its object-side surface is convex and its image-side surface is concave, used to compensate for chromatic aberration and higher-order aberrations generated by the first lens 200. The third lens 400 also has negative optical power, but both its object-side and image-side surfaces are concave, forming a double-concave shape, further diffusing light to balance system field curvature and distortion. The fourth lens 500 has negative optical power, its object-side surface is convex, and its image-side surface is provided with microstructures, utilizing the planar characteristics of the superlens to provide the required optical power contribution within a very small axial space. Through the above-mentioned alternating combination of positive and negative optical power and surface design, light is reasonably deflected within the system. Based on this, this embodiment uses a combination of three aspherical refractive lenses and one superlens, which significantly reduces the number of traditional refractive lenses and lowers the axial length of the lens while ensuring image sharpness, achieving miniaturization.

[0041] In one embodiment, the object-side surface of the fourth lens 500 is an embossed aspherical surface.

[0042] In this embodiment, the fourth lens 500 serves as a superlens. One side of its substrate (object side) is formed into an aspherical surface through an imprinting process, while the other side (image side) retains the microstructure arrangement. Imprinting an aspherical surface refers to imprinting a surface profile with an aspherical sagitta onto a wafer-level substrate using a mold. This profile provides additional optical power and offers greater freedom in surface shape than a traditional spherical surface. When the imprinted aspherical surface is combined with the phase modulation function of the superlens, the fourth lens 500 simultaneously possesses the dual capabilities of a refractive aspherical lens and a diffractive superlens. In the optical path, the imprinted aspherical portion primarily bears the basic optical power, while the microstructure portion is responsible for fine phase compensation and chromatic aberration correction. This hybrid design allows the fourth lens 500 to achieve the functions that would typically require multiple lenses within a single element. Based on this, the introduction of the imprinted aspherical surface further enhances the optical power contribution capability of the fourth lens 500, thereby further shortening the total lens length (TTL). Simultaneously, the aspherical characteristics help correct higher-order aberrations and improve image quality.

[0043] In this embodiment, the fourth lens 500 is a metasurface lens, and its image-side surface 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 fourth lens 500 can achieve optical performance comparable to or even better than that of traditional lenses while maintaining a slim and lightweight design, such as high transmittance, low chromatic aberration, and low distortion. The period range of the microstructure of the fourth lens 500 is 250-400nm, with the optimal period being 280nm in this embodiment; the height of the microstructure is 600-2000nm, with the optimal height being 1500nm in this embodiment; the diameter of the microstructure covers 80-180nm, arranged in square, regular hexagonal, and other shapes; the substrate material is a visible light low refractive index glass material, such as D263TECO, BF33, etc., and the main part of the microstructure is a visible light high refractive index material, such as silicon nitride, titanium oxide, etc.; the microstructure may also contain visible light low refractive index materials for protection, such as silicon oxide, etc.; 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.

[0044] In one embodiment, the hybrid super-refractive small-volume lens satisfies: TTL / EFL ≤ 0.8; where TTL represents the distance from the optical axis center of the object side of the first lens 200 to the image plane, and EFL represents the effective focal length of the entire lens.

[0045] In this embodiment, the condition TTL / EFL ≤ 0.8 characterizes the compactness of the lens, i.e., the ratio of total length to focal length. When this ratio is not greater than 0.8, it indicates that the physical axial length of the lens is compressed to a shorter range while maintaining a given focal length (i.e., angle of view). To achieve this ratio, this embodiment utilizes the reasonable distribution of optical power of the first to third aspherical lenses and the planar phase control characteristics of the fourth superlens. Specifically, the superlens provides a large phase change while occupying less axial space, thereby replacing the spatial thickness required by traditional curved lenses. At the same time, the use of aspherical lenses optimizes the radius of curvature and thickness of each lens, avoiding excessively large axial dimensions due to concentrated optical power.

[0046] This embodiment achieves an ultra-short total length lens structure by satisfying TTL / EFL≤0.8, which is beneficial for integration into thickness-sensitive devices, such as AR glasses or other camera modules with thin and light requirements.

[0047] Furthermore, the hybrid superlens lens satisfies the following condition: EPD / EFL ≤ 0.7; where EPD represents the entrance pupil diameter of the lens system. This further embodiment constrains the relationship between the entrance pupil diameter and the effective focal length. This ensures that the lens has a large relative entrance pupil size, i.e., a large aperture characteristic. Maintaining a large aperture under a short overall length constraint requires each lens, especially the superlens, to have efficient converging ability for peripheral light rays, while suppressing vignetting and aberrations, thereby ensuring bright and clear imaging even in low-light environments.

[0048] In one embodiment, the hybrid super-refractive small-volume lens satisfies the following condition: TTL / MIC < 1.45. A smaller TTL / MIC ratio indicates that the lens, while being axially compact, can support a sufficiently large imaging target surface (e.g., to match image sensors of 1 / 4 inch or larger). For example, in this embodiment, the TTL is limited to no more than 4.4 mm, indicating that the axial dimensions of the entire optical system are controlled within a small range. This requires precise design of the center thickness of each lens, the air gap, and the substrate thickness of the fourth lens. The MIC is defined as the maximum image circle size, that is, the diameter of the largest circular area on the image plane that the lens can form a sharp image. It is limited to no less than 2.52 mm, ensuring that the lens has a sufficient imaging target surface size to match common small-sized image sensors (such as 1 / 4 inch sensors).

[0049] To achieve a minimum image size (MIC) of ≥2.52mm within a compact space of TTL ≤ 4.4mm, in this embodiment, the convex side surface of the first lens 200 and the convex side surface of the second lens 300 together expand the field of view. Meanwhile, the biconcave surface of the third lens 400 and the negative optical power of the fourth superlens control the incident angle of edge rays, ensuring that light rays from the edge field of view can also converge within a larger image circle. In this way, an ultra-short total lens length (≤4.4mm) is achieved while ensuring a sufficient image size (≥2.52mm), thus balancing the potential for miniaturization and high-resolution imaging.

[0050] Among the three conditions for the above-mentioned hybrid refractive-hybrid small-volume lens, when TTL / EFL ≤ 0.8, EPD / EFL ≤ 0.7, and TTL / MIC < 1.45 are simultaneously satisfied, the hybrid refractive-hybrid small-volume lens of this invention can achieve a large relative aperture and an image plane size sufficient to cover mainstream micro image sensors within an extremely short axial dimension. The combination of these three factors overcomes the bottleneck of traditional refractive lenses, which struggle to balance short overall length, large aperture, and large image plane. It is particularly suitable for terminal devices such as AR glasses and micro-projection optical engines, which have stringent requirements for size, brightness, and resolution, achieving a balance between miniaturization, high brightness, and high imaging quality.

[0051] In one embodiment, the lens further includes an aperture stop 100 located on the object side of the first lens 200.

[0052] In this embodiment, the aperture stop is an optical element used to limit the aperture of the imaging beam, and its position has a significant impact on the aberration balance and illumination uniformity of the lens. The aperture stop 100 is placed in front of the first lens 200 (i.e., on the object side), making it the entrance pupil of the system. This front-positioned aperture stop 100 design helps reduce the aperture of each lens, thereby reducing the radial size of the lens; simultaneously, because the aperture stop 100 is located at the very front, it can effectively block off-axis stray light, improving image contrast.

[0053] In the specific optical path of this embodiment, the incident light first passes through the aperture limitation of the aperture stop 100, and then sequentially enters the first lens 200, the second lens 300, the third lens 400, and the fourth superlens. The aperture size of the aperture stop 100 determines the F-number (aperture number) of the system. In this embodiment, the aperture design of the aperture stop 100 can be matched with the optical power of the subsequent lenses, so that sufficient light can still be maintained even with a short TTL. Based on this, by setting the aperture stop 100 on the object side of the first lens 200, the beam width is effectively controlled, the radial dimension of the lens is reduced, and stray light is suppressed, thereby improving the imaging sharpness and signal-to-noise ratio.

[0054] In one embodiment, the first lens 200, the second lens 300, and the third lens 400 are made of plastic, and the fourth lens 500 is made of plastic or glass.

[0055] In this embodiment, the first lens 200, the second lens 300, and the third lens 400 are made of plastic, while the fourth lens 500 is made of either plastic or glass. Plastic materials (such as polycarbonate and cyclic olefin copolymers) have advantages such as ease of injection molding into aspherical surfaces, light weight, and low cost, making them suitable for mass production. Using plastic to fabricate the first three aspherical refractive lenses allows full utilization of their aspherical design freedom to correct aberrations, while simultaneously reducing the overall weight of the lens. The fourth lens 500, as a superlens, can be made of either plastic or glass as its substrate. If a plastic substrate is chosen, the entire lens can achieve an all-plastic structure, further reducing costs; if a glass substrate is chosen, the better thermal stability of glass can be utilized to improve the lens's performance consistency under high and low temperature environments. The microstructure arrangement of the fourth lens 500 can be fabricated on a plastic or glass substrate using nanoimprinting or photolithography processes.

[0056] Based on this, the use of plastic materials reduces the weight and manufacturing cost of the lens. At the same time, the material selection of the fourth lens 500 provides flexibility, allowing the use of glass to improve thermal stability or plastic to further reduce weight, depending on performance requirements.

[0057] In one embodiment, the focal length f of the hybrid superconducting small-volume lens satisfies: f ≥ 5.5 mm.

[0058] In this embodiment, focal length is a key parameter characterizing the lens's angle of view and magnification. Given a specific image size, a longer focal length results in a smaller field of view but a higher center resolution. This embodiment sets the focal length to be no less than 5.5 mm, meaning the lens falls within the medium focal length range, suitable for scenarios requiring a certain telephoto effect or minimal distortion, such as projection lenses in AR glasses, which need to clearly project the microdisplay image into the user's field of view. To achieve f≥5.5mm while maintaining a short overall length, in this embodiment, the positive optical power of the first lens 200 undertakes the main converging function, while the negative optical power of the second and third lenses 400 extends the system's focal length (i.e., the negative optical power lens group diverges the light, thereby increasing the back focal length), and the negative optical power of the fourth superlens further contributes to achieving a long focal length. Through this optical power allocation, even with a limited physical total length, a relatively long effective focal length can still be obtained. The technical advantage of this embodiment is that it achieves a focal length of no less than 5.5 mm within a compact volume, ensuring the lens has a suitable angle of view and magnification, making it suitable for medium field-of-view applications such as AR projection.

[0059] In one embodiment, the field of view (Fov) of the superconducting hybrid small-volume lens satisfies: Fov ≥ 25°.

[0060] In this embodiment, the field of view (Fov) determines the range of the object-side scene that the lens can cover. A diagonal Fov of not less than 25° indicates that the lens has a wide field of view and can capture or project a large image. In AR projection lenses, a larger Fov can provide a more immersive visual experience. To achieve Fov ≥ 25°, in this embodiment, the convex object-side surface of the first lens 200 has a large radius of curvature change to collect large-angle incident light; the convex object-side surface of the second lens 300 further guides edge light; the double concave surface of the third lens 400 effectively controls the field curvature and distortion that may occur under a large field of view; the fourth superlens uses microstructure design to finely modulate the phase of the edge field of view, ensuring that light from each field of view can be correctly focused onto the image plane. At the same time, the front aperture 100 helps to reduce vignetting under a large field of view. Based on this, a field of view of not less than 25° is achieved, providing a wide imaging or projection range and meeting the wide viewing angle requirements of devices such as AR glasses.

[0061] In one embodiment, the aperture number F of the hybrid super-refractive small-volume lens satisfies F≤1.8.

[0062] In this embodiment, the aperture number F is defined as the ratio of focal length to entrance pupil diameter. The smaller the F value, the stronger the light transmission capability of the lens. In this embodiment, F is less than 1.8, which is considered a large aperture lens, enabling a brighter image to be obtained without increasing exposure time or lighting brightness. This is particularly important for AR projection lenses because the light source brightness of AR optical engines is limited, and a large aperture can effectively improve the brightness of the projected image.

[0063] Based on the above solutions, the present invention provides the following various feasible specific embodiments.

[0064] Example 1: like Figure 1 As shown, the hybrid super-refractive lens provided in Embodiment 1 of the present invention includes an aperture stop 100, a first lens 200, a second lens 300, a third lens 400, and a fourth lens 500 arranged along the optical axis from the object plane to the image plane; the first lens 200, the second lens 300, and the third lens 400 are aspherical lenses made of plastic material, and the fourth lens 500 is a super-lens containing an imprinted aspherical surface.

[0065] The first lens 200 has positive optical power, its object side is convex, and its image side is concave; the second lens 300 has negative optical power, its object side is convex, and its image side is concave; the third lens 400 has negative optical power, its object side is concave, and its image side is concave; the fourth lens 500 has negative optical power, its object side is convex, and its image side has a microstructure arrangement.

[0066] like Figure 1 As shown, the incident light enters the first lens 200 after passing through the aperture 100, and then passes through the second lens 300, the third lens 400 and the fourth lens 500 in sequence, finally converging on the imaging surface 600.

[0067] For example, Table 1 details the specific optical data parameters of each lens in the hybrid superconducting small-volume lens provided in Embodiment 1 of the present invention, according to a feasible implementation. The optical data parameters in Table 1 correspond to... Figure 1 The image shows a small-volume hybrid lens with refractive and hyperbolic properties at room temperature.

[0068] Table 1: In Table 1, the surface numbers are assigned according to the surface sequence of each lens. For example, surface number 1 represents aperture 100, surface number 2 represents the object side of the first lens 200, surface number 3 represents the image side of the first lens 200, and so on. Here, Even Asphere represents an aspherical surface, Standard represents a standard surface, Metasurface represents a metasurface, radius of curvature represents the degree of curvature of the lens surface (positive values ​​indicate the surface bends towards the image plane, negative values ​​indicate the surface bends towards the object plane), and spacing represents the central axial distance from the current surface to the next surface. The units for both radius of curvature and spacing are millimeters (mm).

[0069] The surface shape of each aspherical lens satisfies the following equation: ; Where z represents the distance from the vertex of the even-order aspherical surface along the optical axis, r represents 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, and a2, a3, a4, a5, a6, a7, and a8 are the higher-order coefficients of the aspherical surface.

[0070] For example, Table 2 details the higher-order coefficients a2, a3, a4, a5, a6, a7, and a8 of the aspherical lens surface in this embodiment, using a feasible implementation method.

[0071] Table 2: In Table 2, the coefficient a2 with face number 2 has a value of -3.52E-04, and so on.

[0072] For example, Table 3 illustrates the phase of the metasurface in this embodiment with a feasible implementation: Table 3: Where R1 is the normalized radius of the binary surface of the superlens; A1 to A5 represent the coefficients of the phase of the supersurface.

[0073] In this case, the metasurface layer of the superlens is composed of periodically arranged nanopillars, such as... Figure 7 As shown, the arrangement is hexagonal, and the period of the nanopillars is p = 280 nm. Figure 8 As shown, the nanopillars have a height h1 = 1500 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 80 nm to 180 nm. The relationships between the nanopillar transmittance and phase and the nanopillar diameter are shown below. Figure 9 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 10 As shown.

[0074] Based on the specific optical data parameters exemplified in Example 1 of this embodiment, the hybrid superconducting small-volume lens achieves the design structure shown in Table 4 below. Table 4: In Table 4, the working wavelength of this hybrid superconducting small-volume lens is the visible light band; the F-number is 1.8 to ensure sufficient light intake and clear imaging even in darker environments; the focal length is 5.51mm; and the maximum field of view is 25°.

[0075] Figure 2 This is a schematic diagram of the visible light MTF of a hybrid superconducting lens provided in Embodiment 1 of the present invention. It can meet the requirements for high-quality imaging.

[0076] Figure 2 The meanings of each character in the Chinese character set are as follows: F1:T represents field of view 1: meridian (angle) 0.00001°, and F1:R represents field of view 1: sagittal (angle) 0.00001°. F2:T represents field of view 2: meridian (angle) 1.525384°, and F2:R represents field of view 2: sagittal (angle) 1.525384°. F3:T represents field of view 3: Meridian (angle) 3.047239°, and F3:R represents field of view 3: Arc (angle) 3.047239°. F4:T represents the field of view 4: Meridian (angle) 4.564456°, and F4:R represents the field of view 4: Sagitta (angle) 4.564456°; F5:T represents the field of view 5: Meridian (angle) 6.078178°, and F5:R represents the field of view 5: Arc (angle) 6.078178°. F6:T is the field of view 6: Meridian (angle) 7.588760°, F6:R is the field of view 6: Arc (angle) 7.588760°; F7:T represents the field of view 7: Meridian (angle) 9.093089°, and F7:R represents the field of view 7: Arc (angle) 9.093089°. F8:T is the field of view 8: Meridian (angle) 10.586812°, F8:R is the field of view 8: Arc (angle) 10.586812°; F9:T represents the field of view 9: Meridian (angle) 11.00°, and F9:R represents the field of view 9: Arc (angle) 11.00°. F10:T represents the field of view 10: Meridian (angle) 11.80°, and F10:R represents the field of view 10: Arc (angle) 11.801°. F11:T represents the field of view 11: Meridian (angle) 12.50°, and F11:R represents the field of view 11: Arc (angle) 12.50°.

[0077] Figure 3 This is a schematic diagram of the visible light diffusion pattern of the hybrid superconducting small-volume lens provided in Embodiment 1 of the present invention. The diffusion pattern is relatively concentrated and uniformly distributed across the entire long-wavelength band, which can meet the requirements of high-resolution imaging.

[0078] Example 2: like Figure 4 As shown, the hybrid super-refractive lens provided in Embodiment 2 of the present invention includes an aperture stop 100, a first lens 200, a second lens 300, a third lens 400, and a fourth lens 500 arranged along the optical axis from the object plane to the image plane; the first lens 200, the second lens 300, and the third lens 400 are aspherical lenses made of plastic material, and the fourth lens 500 is a super-lens containing an imprinted aspherical surface.

[0079] The first lens 200 has positive optical power, its object side is convex, and its image side is concave; the second lens 300 has negative optical power, its object side is convex, and its image side is concave; the third lens 400 has negative optical power, its object side is concave, and its image side is concave; the fourth lens 500 has negative optical power, its object side is convex, and its image side has a microstructure arrangement.

[0080] like Figure 4 As shown, the incident light enters the first lens 200 after passing through the aperture 100, and then passes through the second lens 300, the third lens 400 and the fourth lens 500 in sequence, finally converging on the imaging surface 600.

[0081] For example, Table 1 details the specific optical data parameters of each lens in the hybrid superconducting small-volume lens provided in Embodiment 2 of the present invention, according to a feasible implementation. The optical data parameters in Table 5 correspond to... Figure 4 The image shows a small-volume hybrid lens with refractive and hyperbolic properties at room temperature.

[0082] Table 5: In Table 5, the surface numbers are assigned according to the surface sequence of each lens. For example, surface number 1 represents aperture 100, surface number 2 represents the object side of the first lens 200, surface number 3 represents the image side of the first lens 200, and so on. Here, Even Asphere represents an aspherical surface, Standard represents a standard surface, Metasurface represents a metasurface, the radius of curvature represents the degree of curvature of the lens surface (positive values ​​indicate the surface bends towards the image plane, negative values ​​indicate the surface bends towards the object plane), and the spacing represents the central axial distance from the current surface to the next surface. The units for both the radius of curvature and the spacing are millimeters (mm).

[0083] The surface shape of each aspherical lens satisfies the following equation: ; Where z represents the distance from the vertex of the even-order aspherical surface along the optical axis, r represents 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, and a2, a3, a4, a5, a6, a7, and a8 are the higher-order coefficients of the aspherical surface.

[0084] For example, Table 6 details the higher-order coefficients a2, a3, a4, a5, a6, a7, and a8 of the aspherical lens surface in this embodiment, using a feasible implementation method.

[0085] Table 6: In Table 6, the coefficient a2 with face number 2 has a value of -1.04E-03, and so on.

[0086] For example, Table 7 illustrates the phase of the metasurface in this embodiment with a feasible implementation: Table 7: Where R1 is the normalized radius of the binary surface of the superlens; A1 to A10 represent the coefficients of the phase of the supersurface.

[0087] In this case, the metasurface layer of the metasurface lens is composed of periodically arranged nanopillars, such as... Figure 7As shown, the arrangement is hexagonal, and the period of the nanopillars is p = 280 nm. Figure 8 As shown, the nanopillars have a height h1 = 1500 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 80 nm to 180 nm. The relationships between the nanopillar transmittance and phase and the nanopillar diameter are shown below. Figure 9 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 11 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.

[0088] Based on the specific optical data parameters exemplified in Embodiment 2, the hybrid superconducting small-volume lens achieves the design structure shown in Table 8 below. Table 8: In Table 8, the working wavelength of this hybrid superconducting small-volume lens is the visible light band; the F-number is 1.8 to ensure sufficient light intake and clear imaging even in darker environments; the focal length is 5.5mm; and the maximum field of view is 25°.

[0089] Figure 5 This is a schematic diagram of the visible light MTF of the hybrid superconducting small-volume lens provided in Embodiment 2 of the present invention. It can meet the requirements of high-quality imaging.

[0090] Figure 6 This is a schematic diagram of the visible light diffusion pattern of the hybrid superconducting lens provided in Embodiment 2 of the present invention. The diffusion pattern is relatively concentrated and uniformly distributed across the entire long wavelength range, which can meet the requirements of high-resolution imaging.

[0091] Figure 6 The meanings of each character in the Chinese character set are as follows: F1:T represents field of view 1: meridian (angle) 0.00001°, and F1:R represents field of view 1: sagittal (angle) 0.00001°. F2:T represents field of view 2: meridian (angle) 1.525384°, and F2:R represents field of view 2: sagittal (angle) 1.525384°. F3:T represents field of view 3: Meridian (angle) 3.047239°, and F3:R represents field of view 3: Arc (angle) 3.047239°. F4:T represents the field of view 4: Meridian (angle) 4.564456°, and F4:R represents the field of view 4: Sagitta (angle) 4.564456°; F5:T represents the field of view 5: Meridian (angle) 6.078178°, and F5:R represents the field of view 5: Arc (angle) 6.078178°. F6:T is the field of view 6: Meridian (angle) 7.588760°, F6:R is the field of view 6: Arc (angle) 7.588760°; F7:T represents the field of view 7: Meridian (angle) 9.093089°, and F7:R represents the field of view 7: Arc (angle) 9.093089°. F8:T is the field of view 8: Meridian (angle) 10.586812°, F8:R is the field of view 8: Arc (angle) 10.586812°; F9:T represents the field of view 9: Meridian (angle) 11.00°, and F9:R represents the field of view 9: Arc (angle) 11.00°. F10:T represents the field of view 10: Meridian (angle) 11.80°, and F10:R represents the field of view 10: Arc (angle) 11.801°. F11:T represents the field of view 11: Meridian (angle) 12.50°, and F11:R represents the field of view 11: Arc (angle) 12.50°.

[0092] In summary, as described in Embodiments 1 and 2, this invention employs a combination of three aspherical refractive lenses and one superlens. While maintaining image sharpness, it significantly reduces the number of traditional refractive lenses and lowers the lens axial length. Furthermore, the introduction of imprinted aspherical surfaces further enhances the optical power contribution of the fourth lens, thereby further shortening the total lens length (TTL). Simultaneously, the aspherical characteristics help correct higher-order aberrations and improve image quality. This achieves a small size and high-fidelity imaging effect.

[0093] This invention also provides a camera module, including the aforementioned hybrid folding-super-folding small-volume lens. Because the camera module uses the aforementioned hybrid folding-super-folding small-volume lens, it also possesses advantages corresponding to optical lenses, such as short overall optical length, small size, and high imaging performance.

[0094] This invention also provides a terminal device, including the camera module described above. The electronic device can be a terminal device with video or photo capture capabilities, such as AR glasses, mobile phones, tablets, laptops, camcorders, video recorders, cameras, intelligent robots, or other devices with photo or video capture capabilities.

[0095] 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 superconducting lens with a small volume, characterized in that, It 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 first lens, the second lens, and the third lens are aspherical lenses, and the fourth lens is a superlens; The first lens has positive optical power, its object side is convex, and its image side is concave. The second lens has negative optical power, its object side is convex, and its image side is concave. The third lens has negative optical power, and its object side is concave, as is its image side. The fourth lens has negative optical power, its object side is convex, and its image side has a microstructure arrangement. The focal length f of the hybrid superconducting small-volume lens satisfies: f≥5.5mm.

2. The hybrid superconducting lens according to claim 1, characterized in that, The object-side surface of the fourth lens is an embossed aspherical surface.

3. The hybrid superconducting lens according to claim 1, characterized in that, The aforementioned hybrid compact lens satisfies the following requirements: TTL / EFL ≤ 0.8; EPD / EFL ≤ 0.7; Wherein, TTL represents the distance from the center of the optical axis on the object side of the first lens to the image plane, EFL represents the effective focal length of the entire lens, and EPD represents the entrance pupil diameter of the lens system.

4. The hybrid superconducting lens according to claim 3, characterized in that, The aforementioned hybrid compact lens satisfies the following requirements: TTL / MIC < 1.45; Wherein, MIC represents the maximum image circle size, and TTL represents the distance from the center of the optical axis on the side of the first lens to the image plane.

5. The hybrid superconducting lens according to claim 1, characterized in that, Its features are, It also includes an aperture stop, which is located on the object side of the first lens.

6. The hybrid superconducting small-volume lens according to claim 1, characterized in that, The first, second, and third lenses are made of plastic, and the fourth lens is made of either plastic or glass.

7. The hybrid superconducting lens according to any one of claims 1 to 6, characterized in that, The field of view (Fov) of the hybrid small-volume lens satisfies: Fov ≥ 25°.

8. The hybrid superconducting lens according to any one of claims 1 to 6, characterized in that, The aperture number F of the hybrid superconducting small-volume lens satisfies F≤1.

8.

9. A camera module, characterized in that, Including the superconducting hybrid small-volume lens as described in any one of claims 1-8 above.

10. A terminal device, characterized in that, Includes the camera module as described in claim 9 above.

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