Grouped telephoto lens

Abstract

The utility model discloses a kind of group long focus lens, group long focus lens includes first lens group, turn-back prism, second lens group and chip imaging assembly;Turn-back prism includes light inlet side and light outlet side, and light inlet side and / or light outlet side of turn-back prism is provided filter film;First lens group includes at least three lenses, is arranged before the light inlet side of turn-back prism;Second lens group includes at least one lens, is arranged after the light outlet side of turn-back prism, or is provided immediately adjacent the light inlet side of turn-back prism, and located between first lens group and the light inlet side of turn-back prism;First lens group and / or second lens group move along optical axis direction and focus.The utility model discloses a kind of group long focus lens, satisfy the demand of miniaturization.

Description

Technical Field

[0001] This utility model relates to the field of optical imaging technology, and in particular to a group telephoto lens. Background Technology

[0002] With the rapid development of mobile communication technology and the widespread adoption of smartphones, the functions and application scenarios of mobile phone lenses are constantly being enriched and expanded. Among them, telephoto lenses, as a functional module capable of long-distance shooting and optical zoom, have received widespread attention in the smartphone market.

[0003] However, for telephoto lenses to capture distant and high-quality images, they inevitably require a long focal length and a large aperture, necessitating a sufficiently large lens size. This creates a trade-off between size, macro capability, and zoom ratio, making it impossible to balance performance and size, and hindering the miniaturization of telephoto lenses. Existing technologies, such as modules that increase the optical path by folding the light path with prisms, have achieved significant progress in recent years; however, the aforementioned trade-offs still persist in telephoto lenses. Utility Model Content

[0004] In view of the above problems, the purpose of this utility model is to provide a clustered telephoto lens that can achieve a smaller size and meet the requirements of miniaturization.

[0005] This invention provides a clustered telephoto lens, comprising a first lens group, a folding prism, a second lens group, and a chip imaging component. The folding prism includes an input side and an output side, and a filter film is disposed on the input side and / or the output side of the folding prism. The first lens group includes at least three lenses arranged in front of the input side of the folding prism. The second lens group includes at least one lens arranged after the output side of the folding prism, or adjacent to the input side of the folding prism, and located between the first lens group and the input side of the folding prism. The first lens group and / or the second lens group move along the optical axis for focusing.

[0006] Optionally, if the first lens group is arranged before the light-incoming side of the folding prism and the second lens group is arranged after the light-outcoming side of the folding prism, the distance M1 from the bottom of the folding prism to the outermost point of the object-side surface of the lens closest to the object side of the first lens group, and the distance M2 from the bottom of the folding prism to the bottom surface of the circuit board where the chip imaging component is located, satisfy: M2+0.5<M1<M2+4.

[0007] Optionally, if the first lens group is arranged before the light-inlet side of the reflecting prism and the second lens group is arranged after the light-outlet side of the reflecting prism, the distance M1 from the bottom of the reflecting prism to the outermost point of the object side surface of the lens closest to the object side of the first lens group, the distance M2 from the bottom of the reflecting prism to the bottom surface of the circuit board where the chip imaging component is located, and the total optical length M3 of the group telephoto lens satisfy: M1 + M2 < M3 - 2.

[0008] Optionally, the distance M4 between the intersection of the zero-field principal ray and the second reflecting surface of the folding prism and the incident optical axis satisfies: M4≥3.5mm.

[0009] Optionally, if the first lens group is arranged before the light-inlet side of the folding prism and the second lens group is arranged after the light-outlet side of the folding prism, in the telephoto state, the distance H8a between the lens of the first lens group closest to the folding prism and the folding prism along the optical axis, and in the near-focus state, the distance H8b between the lens of the first lens group closest to the folding prism and the folding prism along the optical axis, the near-focus object distance H0, and the system focal length f' of the grouped telephoto lens satisfy: ABS(H8a-H8b) / (f'*H0 / (H0-f')-f')≤ 1.

[0010] Optionally, the optical power EFX1 of the first lens group and the system focal length f' of the grouped telephoto lens satisfy: EFX1 / f'<1.

[0011] Optionally, the second lens group includes a fourth lens, wherein the equivalent thickness H9 of the reflecting prism and the center thickness H11 of the fourth lens satisfy: 0.01≤H11 / H9≤0.1.

[0012] Optionally, the equivalent thickness H9 of the reflecting prism and the system focal length f' of the clustered telephoto lens satisfy: 0.25≤f' / H9≤1.2.

[0013] Optionally, the second lens group includes a fourth lens, the focal length f4 of the fourth lens and the system focal length f' of the grouped telephoto lens satisfying: -5≤f4 / f'≤0.

[0014] Optionally, the radius of curvature C3 of the object-side surface of the lens closest to the object side in the first lens group, and the radius of curvature C12 of the object-side surface of the fourth lens in the second lens group, satisfy: 0.5≤C3 / C12≤1.8.

[0015] The clustered telephoto lens provided by this utility model includes a first lens group, a folding prism, a second lens group, and a chip imaging component. The first and second lens groups are used for focusing and image formation. Multiple light path reflections are achieved through the folding prism, significantly reducing the overall height and shoulder height of the clustered telephoto lens. Furthermore, the folding prism includes an input side and an output side, and a filter film is provided on the input and / or output sides of the folding prism, further reducing the height of the lens module. Therefore, the clustered telephoto lens can have a smaller size, meeting the requirements of miniaturization while maintaining the original optical performance. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the folded optical path structure of a clustered telephoto lens according to an embodiment of this application is shown.

[0018] Figure 2 and Figure 3 The diagrams show the front structure of the folded optical path in the telephoto and near-focus states of the grouped telephoto lens according to Embodiment 1 of this application.

[0019] Figure 4 and Figure 5 The MTF curves of the grouped telephoto lens in Example 1 in both telephoto and near-focus states are shown respectively.

[0020] Figure 6 and Figure 7 The diagrams show the front structure of the folded optical path in the telephoto and near-focus states of the grouped telephoto lens according to Embodiment 2 of this application.

[0021] Figure 8 and Figure 9 The MTF curves of the grouped telephoto lens in Example 2 are shown in the telephoto and near-focus states, respectively.

[0022] Figure 10 and Figure 11 The diagrams show the front structure of the folded optical path in the telephoto and near-focus states of the grouped telephoto lens according to Embodiment 3 of this application.

[0023] Figure 12 and Figure 13 The MTF curves of the grouped telephoto lens in Example 3 in both telephoto and near-focus states are shown respectively. Detailed Implementation

[0024] The foregoing and other technical contents, features, and effects of this utility model will be clearly presented in the following detailed description of the preferred embodiments with reference to the accompanying drawings. Through the description of the specific embodiments, a more in-depth and specific understanding can be gained of the technical means and effects adopted by this utility model to achieve its intended purpose. However, the accompanying drawings are for reference and illustration only and are not intended to limit this utility model; some well-known parts may not be shown. In the various drawings, the same elements are represented by similar reference numerals. For clarity, the various parts in the drawings are not necessarily drawn strictly to scale.

[0025] It is important to understand that the terms "first," "second," "third," and "fourth," etc., are used merely to distinguish elements or circuits with similar properties, and do not indicate or imply relative importance or a specific order. The terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, which includes not only the listed elements but also other elements not expressly listed.

[0026] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shape of the sphere shown in the drawings is illustrated by way of example. That is, the shape of the sphere is not limited to that shown in the drawings. The drawings are for illustrative purposes only and are not drawn strictly to scale.

[0027] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the subject is called the object-side surface of the lens, and the surface of each lens closest to the image plane is called the image-side surface of the lens.

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0029] The features, principles and other aspects of this application are described in detail below.

[0030] Please refer to Figure 1 , Figure 1 A schematic diagram of the folded optical path structure of a clustered telephoto lens according to an embodiment of this application is shown.

[0031] A clustered telephoto lens according to an exemplary embodiment of this application includes a first lens group 10, a folding prism P1, a second lens group 20, and a chip imaging assembly 30; the folding prism P1 includes an input side and an output side, and a filter film is disposed on the input side and / or the output side of the folding prism P1; the first lens group 10 includes at least three lenses, arranged in front of the input side of the folding prism P1; the second lens group 20 includes at least one lens, arranged after the output side of the folding prism P1, or disposed immediately adjacent to the input side of the folding prism P1, and located between the first lens group 10 and the input side of the folding prism P1; the first lens group 10 and / or the second lens group 20 move along the optical axis direction for focusing.

[0032] The reflecting prism P1 includes an input side and an output side. In one embodiment, as shown... Figure 1 As shown, the light-inlet side and the light-outlet side can be the same surface; however, this application is not limited to this. For example, the light-inlet side and the light-outlet side can be located at the top and bottom of the folding prism P1, respectively, or at the top and waist of the folding prism P1, etc. After entering the folding prism P1 from the light-inlet side, the light can be reflected at least twice before exiting from the light-outlet side. If the first lens group 10 is arranged before the light-inlet side of the folding prism P1, and the second lens group 20 is arranged after the light-outlet side of the folding prism P1, the light can pass through the first lens group 10, the folding prism P1, and the second lens group 20 in sequence, and finally be projected onto the imaging surface IMG of the chip imaging assembly 30. If the first lens group 10 is arranged before the light-inlet side of the folding prism P1, and the second lens group 20 is arranged adjacent to the light-inlet side of the folding prism P1 and located between the first lens group 10 and the light-inlet side of the folding prism P1, then light can pass through the first lens group 10, the second lens group 20 and the folding prism P1 in sequence, and finally be projected onto the imaging surface IMG of the chip imaging assembly 30.

[0033] The retroreflector prism P1 can perform multiple light path reflections, achieving light path folding and changing the original straight direction of light. The back focal length of the lens can be folded inside the retroreflector prism P1, allowing light rays emitted from the retroreflector prism P1 to reach the imaging plane IMG after a shorter optical path, thus shortening the back focal length of the lens and significantly reducing the overall height and shoulder height of the lens module. By rationally allocating the optical power, spacing, and refractive index of each lens in the first lens group 10 and the second lens group 20, as well as the angle and thickness of the retroreflector prism P1, the overall height and shoulder height of the grouped telephoto lenses can be significantly reduced. Moreover, the retroreflector prism P1 includes an input side and an output side, and the input side and / or output side of the retroreflector prism P1 are equipped with a filter film, which can further reduce the height of the lens module.

[0034] The first lens group 10 and / or the second lens group 20 move along the optical axis for autofocus (AF), achieving excellent image quality at close range (e.g., 20cm) and infinity. Optionally, the first lens group 10, while moving along the optical axis for AF, can also move in the XY direction (with the optical axis pointing to the Z-axis) to achieve OIS (Optical Image Stabilization). Furthermore, the grouping configuration allows the AF & OIS travel to be 50%-80% of the conventional focusing travel, meeting the requirements for reduced height and facilitating the miniaturization of the lens module.

[0035] Therefore, the clustered telephoto lens of this utility model can achieve a smaller size and meet the requirements of miniaturization.

[0036] In an exemplary embodiment, according to the grouped telephoto lens of this application, the first lens group 10 may include at least three lenses, for example, three, four, or five lenses; the lenses may be spherically or aspherically molded. In one exemplary embodiment, the lens closest to the object side of the first lens group 10 has positive optical power and can function as a light-gathering element. In one exemplary embodiment, such as... Figure 1 As shown, the first lens group 10 includes a first lens L1, a second lens L2, and a third lens L3 sequentially from the object side to the image side. The first lens L1 has positive optical power, the second lens L2 has negative optical power, and the third lens L3 has positive optical power. In one exemplary embodiment, the second lens L2 may be meniscus-shaped, with its object side being concave.

[0037] In an exemplary implementation, such as Figure 1 As shown, according to the grouped telephoto lens of this application, the second lens group 20 includes only one lens, which can reduce the module shoulder height. This lens is designated as the fourth lens L4, which can be spherically or aspherically molded. In one exemplary embodiment, the fourth lens L4 has negative optical power to correct chromatic aberration. In another exemplary embodiment, the center of the fourth lens L4 convexes towards the object side, and the object side surface of the fourth lens L4 has two troughs, i.e., one trough from the center to each side.

[0038] In an exemplary embodiment, the lenses in the first lens group 10 and the second lens group 20 of the present application can be made of glass, plastic, or a glass-plastic hybrid, etc.

[0039] In an exemplary embodiment, the grouped telephoto lens according to this application further includes an aperture stop STO. Preferably, the aperture stop STO may be disposed on the object side of the lens closest to the object side of the first lens group 10. However, this application is not limited to this, and the aperture stop STO may also be disposed between two adjacent lenses among the plurality of lenses in the first lens group 10, etc.

[0040] In an exemplary implementation, such as Figure 1As shown, according to the grouped telephoto lens of this application, if the first lens group 10 is arranged before the light-incoming side of the reflecting prism P1, and the second lens group 20 is arranged after the light-outcoming side of the reflecting prism P1, the distance M1 from the bottom of the reflecting prism P1 to the outermost point of the object-side surface of the lens closest to the object side of the first lens group 10, and the distance M2 from the bottom of the reflecting prism P1 to the bottom surface of the circuit board 40 where the chip imaging component 30 is located, satisfy: M2+0.5<M1<M2+4. Therefore, by controlling the size of the distance M1 from the bottom of the reflecting prism P1 to the outermost point of the object-side surface of the lens closest to the object side of the first lens group 10, and the distance M2 from the bottom of the reflecting prism P1 to the bottom surface of the circuit board 40 where the chip imaging component 30 is located, it is beneficial to reduce the shoulder height of the lens module and achieve miniaturization of the lens module.

[0041] In an exemplary implementation, such as Figure 1 As shown, according to the grouped telephoto lens of this application, if the first lens group 10 is arranged before the light-incoming side of the reflecting prism P1, and the second lens group 20 is arranged after the light-outcoming side of the reflecting prism P1, the distance M1 from the bottom of the reflecting prism P1 to the outermost point of the object-side surface of the lens closest to the object side of the first lens group 10, the distance M2 from the bottom of the reflecting prism P1 to the bottom surface of the circuit board 40 where the chip imaging assembly 30 is located, and the total optical length M3 of the grouped telephoto lens ( Figure 2 (not shown in the diagram), satisfying: M1 + M2 < M3 - 2. Then, by controlling the distance M1 from the bottom of the folding prism P1 to the outermost point of the object side of the lens closest to the object side of the first lens group 10, the distance M2 from the bottom of the folding prism P1 to the bottom surface of the circuit board 40 where the chip imaging component 30 is located, and the total optical length M3 of the grouped telephoto lens, it is beneficial to reduce the total optical length of the system and realize the miniaturization of the lens module.

[0042] In an exemplary implementation, such as Figure 1 As shown, the clustered telephoto lens according to this application can satisfy M4≥3.5mm; where M4 is the distance between the intersection of the zero-field principal ray and the second reflecting surface of the folding prism P1 and the incident optical axis. Satisfying M4≥3.5mm, and controlling the range of values ​​for the distance M4 between the intersection of the zero-field principal ray and the second reflecting surface of the folding prism P1 and the incident optical axis, is beneficial for lens module assembly.

[0043] In an exemplary implementation, such as Figure 1As shown, according to the clustered telephoto lens of this application, if the first lens group 10 is arranged before the light-incoming side of the reflecting prism P1, and the second lens group 20 is arranged after the light-outcoming side of the reflecting prism P1, in the telephoto state, the distance H8a between the lens of the first lens group 10 closest to the reflecting prism P1 and the reflecting prism P1 along the optical axis, and in the near-focus state, the distance H8b between the lens of the first lens group 10 closest to the reflecting prism P1 and the reflecting prism P1 along the optical axis, the near-focus object distance H0, and the system focal length f' of the clustered telephoto lens satisfy: ABS(H8a-H8b) / (f'*H0 / (H0-f')-f')≤ 1. This can help reduce the travel during lens focusing and is beneficial for the miniaturization of the lens module.

[0044] In an exemplary embodiment, the grouped telephoto lens according to this application can satisfy EFX1 / f'<1; where EFX1 is the optical power of the first lens group 10, and f' is the system focal length of the grouped telephoto lens. Satisfying EFX1 / f'<1, by controlling the range of the ratio between the optical power EFX1 of the first lens group 10 and the system focal length f' of the grouped telephoto lens, is beneficial for correcting aberrations and improving image quality.

[0045] In an exemplary implementation, such as Figure 1 As shown, the grouped telephoto lens according to this application satisfies 0.01≤H11 / H9≤0.1; wherein, the second lens group 20 includes a fourth lens L4, H9 is the equivalent thickness of the reflecting prism P1, and H11 is the center thickness of the fourth lens L4. Satisfying 0.01≤H11 / H9≤0.1, by controlling the ratio range of the center thickness H11 of the fourth lens L4 and the equivalent thickness H9 of the reflecting prism P1, it is beneficial to control the height of the prism light exit surface module, which is beneficial to reducing the shoulder height of the lens module and realizing the miniaturization of the lens module.

[0046] In an exemplary embodiment, the clustered telephoto lens according to this application satisfies 0.25≤f' / H9≤1.2; where H9 is the equivalent thickness of the reflecting prism P1, and f' is the system focal length of the clustered telephoto lens. Satisfying 0.25≤f' / H9≤1.2, by controlling the range of the ratio between the equivalent thickness H9 of the reflecting prism P1 and the system focal length f' of the clustered telephoto lens, is beneficial for controlling the thickness of the prism within a reasonable range, for optimizing optical system aberrations, and for reducing system size, thus achieving miniaturization of the lens module.

[0047] In an exemplary embodiment, the clustered telephoto lens according to this application satisfies -5 ≤ f4 / f' ≤ 0; wherein, the second lens group 20 includes a fourth lens L4, f4 is the focal length of the fourth lens L4, and f' is the system focal length of the clustered telephoto lens. Satisfying -5 ≤ f4 / f' ≤ 0, by controlling the range of the ratio of the focal length f4 of the fourth lens L4 to the system focal length f' of the clustered telephoto lens, is beneficial for correcting distortion and improving image quality.

[0048] In an exemplary embodiment, the grouped telephoto lens according to this application satisfies 0.5 ≤ C3 / C12 ≤ 1.8; where C3 is the radius of curvature of the object-side surface of the lens closest to the object in the first lens group 10, the second lens group 20 includes a fourth lens L4, and C12 is the radius of curvature of the object-side surface of the fourth lens L4. Satisfying 0.5 ≤ C3 / C12 ≤ 1.8, by controlling the range of the ratio of the radius of curvature C3 of the object-side surface of the lens closest to the object in the first lens group 10 to the radius of curvature C12 of the object-side surface of the fourth lens L4, is beneficial for meeting the system focal length requirements and improving image quality.

[0049] In an exemplary embodiment, the grouped telephoto lens according to this application satisfies 0.2 ≤ f1 / f' ≤ 1; wherein, the first lens group 10 includes a first lens L1 closest to the object side, f1 is the focal length of the first lens L1, and f' is the system focal length of the grouped telephoto lens. Satisfying 0.2 ≤ f1 / f' ≤ 1, by controlling the range of the ratio of the focal length f1 of the first lens L1 to the system focal length f' of the grouped telephoto lens, is beneficial for converging light and achieving a large aperture.

[0050] In an exemplary embodiment, the grouped telephoto lens according to this application satisfies 0.01≤AB1 / N1≤0.05; wherein, the first lens group 10 includes a first lens L1 closest to the object side, AB1 is the Abbe number of the first lens L1, and N1 is the refractive index of the first lens L1. Satisfying 0.01≤AB1 / N1≤0.05, by controlling the range of the ratio of the Abbe number AB1 to the refractive index N1 of the first lens L1, is beneficial for correcting chromatic aberration and achieving high image quality at a large aperture.

[0051] In an exemplary embodiment, the clustered telephoto lens according to this application satisfies 1≤Np≤1.9; where Np is the refractive index of the reflecting prism P1. Satisfying 1≤Np≤1.9, by controlling the range of the refractive index Np of the reflecting prism P1, is beneficial to controlling the signal-to-noise ratio of the system and improving the imaging quality.

[0052] In an exemplary embodiment, the grouped telephoto lens according to this application satisfies 0.25mm≤H12≤14mm; where H12 is the distance from the object side of the lens closest to the imaging surface IMG in the second lens group 20 to the imaging surface IMG. Satisfying 0.25mm≤H12≤14mm, by controlling the range of the distance H12 from the object side of the lens closest to the imaging surface IMG in the second lens group 20 to the imaging surface IMG, helps to reduce the probability of speckled imaging and improve image quality.

[0053] In an exemplary embodiment, the folding prism P1 can be modified by chamfering or rounding. The chamfered and rounded corners are suppressed by coating, screen printing or other methods to suppress stray light, which helps to improve the reliability of the module and reduce stray light.

[0054] In an exemplary embodiment, the autofocus (AF) drive of the first lens group 10 may employ a voice coil motor (VCM), and its motion guide structure may be selected from solutions such as suspension wires, springs, balls, or guide rods.

[0055] Based on the same inventive concept, the electronic device according to the exemplary embodiments of this application includes the aforementioned clustered telephoto lens. The electronic device may be, but is not limited to, a smartphone, tablet computer, laptop computer, gimbal camera, surveillance lens, vehicle monitoring equipment, and other imaging devices. Implementation of this electronic device can be found in the embodiments of the clustered telephoto lens; repeated details will not be elaborated further.

[0056] However, those skilled in the art will understand that the number of lenses constituting the optical imaging lens can be varied to obtain the various results and advantages described herein without departing from the technical solutions claimed in this application. For example, although four lenses are described as an example in the embodiments, the optical imaging lens is not limited to including four lenses. If desired, the optical imaging lens may also include other numbers of lenses.

[0057] The following describes in further detail, with reference to the accompanying drawings, specific embodiments of the clustered telephoto lens applicable to the above-described embodiments.

[0058] Example 1

[0059] The following is for reference Figure 2 and Figure 3 Describes a clustered telephoto lens according to Embodiment 1 of this application. Figure 2 and Figure 3 The diagrams show the front structure of the folded optical path in the telephoto and near-focus states of the grouped telephoto lens according to Embodiment 1 of this application.

[0060] like Figure 2 and Figure 3As shown, the clustered telephoto lens includes a first lens group 10, a reflecting prism P1, a second lens group 20, and a chip imaging assembly 30. The reflecting prism P1 includes an input side and an output side, and a filter film is provided on the input side and / or the output side of the reflecting prism P1. The first lens group 10 is arranged before the input side of the reflecting prism P1, and the second lens group 20 is arranged after the output side of the reflecting prism P1. In other embodiments, the first lens group 10 is arranged before the input side of the reflecting prism P1, and the second lens group 20 is arranged adjacent to the input side of the reflecting prism P1 and located between the first lens group 10 and the input side of the reflecting prism P1. The first lens group 10 and / or the second lens group 20 move along the optical axis to focus. The first lens group 10 includes a first lens L1, a second lens, and a third lens L3 sequentially from the object side to the image side. The second lens group 20 includes a fourth lens L4. An aperture stop STO can be provided on the object side of the first lens L1.

[0061] Please refer to the following as well. Figure 2 , Figure 3 As per Table 1, the first lens L1 has positive optical power, with both its object-side and image-side surfaces being convex. The second lens L2 has negative optical power, with both its object-side and image-side surfaces being concave. The third lens L3 has positive optical power, with both its object-side and image-side surfaces being convex. The reflecting prism P1 has an input side and an output side. The fourth lens L4 has positive optical power, with both its object-side and image-side surfaces being concave. Light from the object first passes through the first lens group 10, specifically the aperture stop STO, the first lens L1, the second lens L2, and the third lens L3; then it enters the reflecting prism P1 through the input side, undergoes at least two internal reflections within the reflecting prism P1, and exits through the output side; after passing through the second lens group 20, i.e., the fourth lens L4, it is projected onto the imaging surface IMG of the chip imaging assembly 30.

[0062] Table 1 shows the basic parameters of the clustered telephoto lens of Example 1, where the units for radius of curvature, thickness, and focal length are millimeters (mm).

[0063] Table 1:

[0064]

[0065] Wherein, L1 R1 represents the object-side surface of the first lens L1, and L1 R2 represents the image-side surface of the first lens L1; L2 R1 represents the object-side surface of the second lens L2, and L2 R2 represents the image-side surface of the second lens L2; ​​L3 R1 represents the object-side surface of the third lens L3, and L3 R2 represents the image-side surface of the third lens L3; Prism R1 represents the light-inlet side of the folding prism P1, and Prism R2 represents the light-outlet side of the folding prism P1; L4 R1 represents the object-side surface of the fourth lens L4, and L4 R2 represents the image-side surface of the fourth lens L4. In this context, the thickness corresponding to "8 L3 R2" in the surface serial number is "0.45 / 1.43". 0.45mm represents the distance H8a along the optical axis between the third lens L3 (the lens in the first lens group 10 closest to the reflecting prism P1) and the reflecting prism P1 in the telephoto state, and 1.43mm represents the distance H8b along the optical axis between the third lens L3 (the lens in the first lens group 10 closest to the reflecting prism P1) and the reflecting prism P1 in the near-focus state (macro, such as 20cm). The sign of the radius of curvature is determined by the left or right of the surface's center, with the object side on the left and the image side on the right. If the surface is to the left of the center, the radius of curvature is positive; if the surface is to the right of the center, the radius of curvature is negative.

[0066] In Embodiment 1, the object-side surface and image-side surface of any one of the first lens L1 to the fourth lens L4 can both be even-order aspherical surfaces. The shape of the aspherical surface can be defined using, but is not limited to, the following aspherical surface formula:

[0067] (1)

[0068] Where x is the distance vector from the vertex of the extended aspherical surface at a height of h along the optical axis; c is the paraxial curvature of the extended aspherical surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the radius of curvature in Table 1 above); k is the conic coefficient; Ai is the correction coefficient of the i-th order of the extended aspherical surface.

[0069] Table 2 shows the conic coefficients and higher-order coefficients A2, A4, A6, A8, A10, A12, A14, A16, A18 and A20 that can be used when the object side and image side of the first lens L1 to the fourth lens L4 in Embodiment 1 are even-order aspherical surfaces.

[0070] Table 2:

[0071]

[0072] In Example 1, the system focal length f' of the clustered telephoto lens is 13.85mm, the aperture value F# is 2.65, the imaging circle diameter is 8.24mm, and the operating wavelength is 420~380nm. In the telephoto state, the distance H8a between the third lens L3 (i.e., the lens of the first lens group 10 closest to the reflecting prism P1) and the reflecting prism P1 along the optical axis is [missing information]. In the near-focus state, the distance H8b between the third lens L3 (i.e., the lens of the first lens group 10 closest to the reflecting prism P1) and the reflecting prism P1 along the optical axis is [missing information]. The near-focus object distance H0 (e.g., 20cm) and the system focal length f' of the clustered telephoto lens are related by the formula ABS(H8a-H8b) / (f'*H0 / (H0-f')-f')=0.95, which satisfies ABS(H8a-H8b) / (f'*H0 / (H0-f')-f')≤ 1. The center thickness H11 of the fourth lens L4 and the equivalent thickness H9 of the reflecting prism P1 are related by the formula H11 / H9 = 0.035, satisfying 0.01 ≤ H11 / H9 ≤ 0.1. The equivalent thickness H9 of the reflecting prism P1 and the system focal length f' of the group telephoto lens are related by the formula f' / H9 = 0.962, satisfying 0.25 ≤ f' / H9 ≤ 1.2. The focal length f1 of the first lens L1 and the system focal length f' of the group telephoto lens are related by the formula f1 / f' = 0.604, satisfying 0.2 ≤ f1 / f' ≤ 1. The focal length f4 of the fourth lens L4 and the system focal length f' of the group telephoto lens are related by the formula f4 / f' = -1.716, satisfying -5 ≤ f4 / f' ≤ 0. The Abbe number AB1 of the first lens L1 is related to its refractive index N1 by the formula AB1 / N1 = 0.028, satisfying 0.01 ≤ AB1 / N1 ≤ 0.05. The radius of curvature C3 of the object-side surface of the lens closest to the object side in the first lens group 10 is related to the radius of curvature C12 of the object-side surface of the fourth lens L4 by the formula C3 / C12 = 1.429, satisfying 0.5 ≤ C3 / C12 ≤ 1.8. The refractive index Np of the reflecting prism P1 is 1.680, satisfying 1 ≤ Np ≤ 1.9. The distance H12 from the object-side surface of the lens closest to the imaging plane IMG in the second lens group 20 to the imaging plane IMG is 1.410 mm, satisfying 0.25 mm ≤ H12 ≤ 14 mm.

[0073] Figure 4 The diagram shows the MTF curve of the clustered telephoto lens in the telephoto state of Example 1. The MTF (Modulation Transfer Function) curve shows the transmission of image details (i.e. image contrast) at different spatial frequencies by the imaging system. At infinity and a spatial frequency of 125 lp / mm, the OTF modulus is greater than 0.2, indicating good resolution. Figure 5The diagram shows the MTF (Modulation Transfer Function) curve of the clustered telephoto lens in Example 1 at close focus. The MTF curve shows the imaging system's transmission of image details (i.e., image contrast) at different spatial frequencies. At a close focus of 20cm and a spatial frequency of 120lp / mm, the MTF modulus is greater than 0.1, indicating excellent resolution. According to... Figures 4 to 5 It can be seen that the clustered telephoto lens given in Example 1 has good resolution in both telephoto and close-focus states, and can achieve good image quality.

[0074] Example 2

[0075] The following is for reference Figure 6 and Figure 7 Description of a clustered telephoto lens according to Embodiment 2 of this application. Figure 6 and Figure 7 The diagrams show the front structure of the folded optical path in the telephoto and near-focus states of the grouped telephoto lens according to Embodiment 2 of this application.

[0076] like Figure 6 and Figure 7 As shown, the clustered telephoto lens includes a first lens group 10, a reflecting prism P1, a second lens group 20, and a chip imaging assembly 30. The reflecting prism P1 includes an input side and an output side, and a filter film is provided on the input side and / or the output side of the reflecting prism P1. The first lens group 10 is arranged before the input side of the reflecting prism P1, and the second lens group 20 is arranged after the output side of the reflecting prism P1. In other embodiments, the first lens group 10 is arranged before the input side of the reflecting prism P1, and the second lens group 20 is arranged adjacent to the input side of the reflecting prism P1 and located between the first lens group 10 and the input side of the reflecting prism P1. The first lens group 10 and / or the second lens group 20 move along the optical axis to focus. The first lens group 10 includes a first lens L1, a second lens L2, and a third lens L3 sequentially from the object side to the image side. The second lens group 20 includes a fourth lens L4. An aperture stop STO can be set on the object side of the first lens L1.

[0077] Please refer to the following as well. Figure 6 , Figure 7According to Table 3, the first lens L1 has positive optical power, with both its object-side and image-side surfaces being convex. The second lens L2 has negative optical power, with both its object-side and image-side surfaces being concave. The third lens L3 has positive optical power, with both its object-side and image-side surfaces being concave. The reflecting prism P1 has an input side and an output side. The fourth lens L4 has positive optical power, with both its object-side and image-side surfaces being concave. Light from the object first passes through the first lens group 10, specifically the aperture stop STO, the first lens L1, the second lens L2, and the third lens L3; then it enters the reflecting prism P1 through the input side, undergoes at least two reflections inside the reflecting prism P1, and exits through the output side; after passing through the second lens group 20, i.e., the fourth lens L4, it is projected onto the imaging surface IMG of the chip imaging assembly 30.

[0078] Table 3 shows the basic parameters of the clustered telephoto lens of Example 2, where the units for radius of curvature, thickness, and focal length are millimeters (mm).

[0079] Table 3:

[0080]

[0081] Table 4 shows the conic coefficients and higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 for the object-side and image-side surfaces of the first lens L1 to the fourth lens L4 in Embodiment 2 to be even-order aspherical surfaces. The surface shape of each even-order aspherical surface can be defined by formula (1) given in Embodiment 1 above.

[0082] Table 4:

[0083]

[0084] In Example 2, the system focal length f' of the clustered telephoto lens is 13.81mm, the aperture value F# is 2.65, the imaging circle diameter is 8.33mm, and the operating wavelength is 420~380nm. In the telephoto state, the distance H8a between the third lens L3 (i.e., the lens of the first lens group 10 closest to the reflecting prism P1) and the reflecting prism P1 along the optical axis is [missing information]. In the near-focus state, the distance H8b between the third lens L3 (i.e., the lens of the first lens group 10 closest to the reflecting prism P1) and the reflecting prism P1 along the optical axis is [missing information]. The near-focus object distance H0 (e.g., 20cm) and the system focal length f' of the clustered telephoto lens have the relationship ABS(H8a-H8b) / (f'*H0 / (H0-f')-f')=0.95, which satisfies ABS(H8a-H8b) / (f'*H0 / (H0-f')-f')≤ 1. The center thickness H11 of the fourth lens L4 and the equivalent thickness H9 of the reflecting prism P1 are related by the formula H11 / H9 = 0.035, satisfying 0.01 ≤ H11 / H9 ≤ 0.1. The equivalent thickness H9 of the reflecting prism P1 and the system focal length f' of the group telephoto lens are related by the formula f' / H9 = 0.962, satisfying 0.25 ≤ f' / H9 ≤ 1.2. The focal length f1 of the first lens L1 and the system focal length f' of the group telephoto lens are related by the formula f1 / f' = 0.564, satisfying 0.2 ≤ f1 / f' ≤ 1. The focal length f4 of the fourth lens L4 and the system focal length f' of the group telephoto lens are related by the formula f4 / f' = -1.791, satisfying -5 ≤ f4 / f' ≤ 0. The Abbe number AB1 of the first lens L1 is related to its refractive index N1 by the formula AB1 / N1 = 0.028, satisfying 0.01 ≤ AB1 / N1 ≤ 0.05. The radius of curvature C3 of the object-side surface of the lens closest to the object side in the first lens group 10 is related to the radius of curvature C12 of the object-side surface of the fourth lens L4 by the formula C3 / C12 = 1.349, satisfying 0.5 ≤ C3 / C12 ≤ 1.8. The refractive index Np of the reflecting prism P1 is 1.720, satisfying 1 ≤ Np ≤ 1.9. The distance H12 from the object-side surface of the lens closest to the imaging plane IMG in the second lens group 20 to the imaging plane IMG is 1.405 mm, satisfying 0.25 mm ≤ H12 ≤ 14 mm.

[0085] Figure 8 The diagram shows the MTF curve of the clustered telephoto lens in the telephoto state of Example 2. The MTF (Modulation Transfer Function) curve shows the transmission of image details (i.e. image contrast) at different spatial frequencies by the imaging system. At infinity and a spatial frequency of 125 lp / mm, the OTF modulus is greater than 0.2, indicating good resolution. Figure 9The diagram shows the MTF (Modulation Transfer Function) curve of the clustered telephoto lens in Example 2 at close focus. The MTF curve shows the imaging system's transmission of image details (i.e., image contrast) at different spatial frequencies. At a close focus of 20cm and a spatial frequency of 120lp / mm, the MTF modulus is greater than 0.1, indicating excellent resolution. According to... Figures 8 to 9 It can be seen that the clustered telephoto lens given in Example 2 has good resolution in both telephoto and close-focus states, and can achieve good image quality.

[0086] Example 3

[0087] The following is for reference Figure 10 and Figure 11 Description of a clustered telephoto lens according to Embodiment 2 of this application. Figure 10 and Figure 11 The diagrams show the front structure of the folded optical path in the telephoto and near-focus states of the grouped telephoto lens according to Embodiment 3 of this application.

[0088] like Figure 10 and Figure 11 As shown, the clustered telephoto lens includes a first lens group 10, a reflecting prism P1, a second lens group 20, and a chip imaging assembly 30. The reflecting prism P1 includes an input side and an output side, and a filter film is provided on the input side and / or the output side of the reflecting prism P1. The first lens group 10 is arranged before the input side of the reflecting prism P1, and the second lens group 20 is arranged after the output side of the reflecting prism P1. In other embodiments, the first lens group 10 is arranged before the input side of the reflecting prism P1, and the second lens group 20 is arranged adjacent to the input side of the reflecting prism P1 and located between the first lens group 10 and the input side of the reflecting prism P1. The first lens group 10 and / or the second lens group 20 move along the optical axis to focus. The first lens group 10 includes a first lens L1, a second lens, and a third lens L3 sequentially from the object side to the image side. The second lens group 20 includes a fourth lens L4. An aperture stop STO can be provided on the object side of the first lens L1.

[0089] Please refer to the following as well. Figure 10 , Figure 11According to Table 5, the first lens L1 has positive optical power, with both its object-side and image-side surfaces being convex. The second lens L2 has negative optical power, with both its object-side and image-side surfaces being concave. The third lens L3 has positive optical power, with both its object-side and image-side surfaces being concave. The reflecting prism P1 has an input side and an output side. The fourth lens L4 has positive optical power, with both its object-side and image-side surfaces being concave. Light from the object first passes through the first lens group 10, specifically the aperture stop STO, the first lens L1, the second lens L2, and the third lens L3; then it enters the reflecting prism P1 through the input side, undergoes at least two reflections inside the reflecting prism P1, and exits through the output side; after passing through the second lens group 20, i.e., the fourth lens L4, it is projected onto the imaging surface IMG of the chip imaging assembly 30.

[0090] Table 5 shows the basic parameters of the clustered telephoto lens of Example 3, where the units for radius of curvature, thickness, focal length, and aperture are all millimeters (mm).

[0091] Table 5:

[0092]

[0093] Table 6 shows the conic coefficients and higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 for the object-side and image-side surfaces of the first lens L1 to the fourth lens L4 in Embodiment 3 to be even-order aspherical surfaces. The surface shape of each even-order aspherical surface can be defined by formula (1) given in Embodiment 1 above.

[0094] Table 6:

[0095]

[0096] In Example 3, the system focal length f' of the clustered telephoto lens is 13.88mm, the aperture value F# is 2.65, the imaging circle diameter is 8.31mm, and the operating wavelength is 420~380nm. In the telephoto state, the distance H8a between the third lens L3 (i.e., the lens of the first lens group 10 closest to the reflecting prism P1) and the reflecting prism P1 along the optical axis is [missing information]. In the near-focus state, the distance H8b between the third lens L3 (i.e., the lens of the first lens group 10 closest to the reflecting prism P1) and the reflecting prism P1 along the optical axis is [missing information]. The near-focus object distance H0 (e.g., 20cm) and the system focal length f' of the clustered telephoto lens have the relationship ABS(H8a-H8b) / (f'*H0 / (H0-f')-f')=0.95, which satisfies ABS(H8a-H8b) / (f'*H0 / (H0-f')-f')≤ 1. The center thickness H11 of the fourth lens L4 and the equivalent thickness H9 of the reflecting prism P1 are related by the formula H11 / H9 = 0.035, satisfying 0.01 ≤ H11 / H9 ≤ 0.1. The equivalent thickness H9 of the reflecting prism P1 and the system focal length f' of the group telephoto lens are related by the formula f' / H9 = 0.962, satisfying 0.25 ≤ f' / H9 ≤ 1.2. The focal length f1 of the first lens L1 and the system focal length f' of the group telephoto lens are related by the formula f1 / f' = 0.563, satisfying 0.2 ≤ f1 / f' ≤ 1. The focal length f4 of the fourth lens L4 and the system focal length f' of the group telephoto lens are related by the formula f4 / f' = -1.841, satisfying -5 ≤ f4 / f' ≤ 0. The Abbe number AB1 of the first lens L1 is related to its refractive index N1 by the formula AB1 / N1 = 0.028, satisfying 0.01 ≤ AB1 / N1 ≤ 0.05. The radius of curvature C3 of the object-side surface of the lens closest to the object side in the first lens group 10 is related to the radius of curvature C12 of the object-side surface of the fourth lens L4 by the formula C3 / C12 = 1.360, satisfying 0.5 ≤ C3 / C12 ≤ 1.8. The refractive index Np of the reflecting prism P1 is 1.720, satisfying 1 ≤ Np ≤ 1.9. The distance H12 from the object-side surface of the lens closest to the imaging plane IMG in the second lens group 20 to the imaging plane IMG is 1.391 mm, satisfying 0.25 mm ≤ H12 ≤ 14 mm.

[0097] Figure 12 The diagram shows the MTF curve of the clustered telephoto lens in the telephoto state of Example 3. The MTF (Modulation Transfer Function) curve shows the transmission of image details (i.e. image contrast) at different spatial frequencies by the imaging system. At infinity and a spatial frequency of 125 lp / mm, the OTF modulus is greater than 0.2, indicating good resolution. Figure 13The diagram shows the MTF (Modulation Transfer Function) curve of the clustered telephoto lens in Example 3 at close focus. The MTF curve shows the imaging system's transmission of image details (i.e., image contrast) at different spatial frequencies. At a close focus of 20cm and a spatial frequency of 120lp / mm, the MTF modulus is greater than 0.1, indicating excellent resolution. According to... Figures 12 to 13 As can be seen, the clustered telephoto lens given in Example 3 has good resolution in both telephoto and close-focus states, and can achieve good image quality.

[0098] In summary, Examples 1, 2, and 3 satisfy the relationships shown in Table 7.

[0099] Table 7:

[0100]

[0101] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the utility model involved in this application is not limited to the technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A clustered telephoto lens, characterized in that, It includes a first lens group, a folding prism, a second lens group, and a chip imaging component; The folding prism includes an input side and an output side, and a filter film is provided on the input side and / or the output side of the folding prism; The first lens group includes at least three lenses and is arranged in front of the light-inlet side of the folding prism; the second lens group includes at least one lens and is arranged after the light-outlet side of the folding prism, or is arranged immediately adjacent to the light-inlet side of the folding prism and is located between the first lens group and the light-inlet side of the folding prism; the first lens group and / or the second lens group move along the optical axis to focus.

2. The grouped telephoto lens according to claim 1, characterized in that, If the first lens group is arranged before the light-inlet side of the folding prism and the second lens group is arranged after the light-outlet side of the folding prism, the distance M1 from the bottom of the folding prism to the outermost point of the object side surface of the lens closest to the object side of the first lens group, and the distance M2 from the bottom of the folding prism to the bottom surface of the circuit board where the chip imaging component is located, satisfy: M2+0.5<M1<M2+4.

3. The grouped telephoto lens according to claim 1, characterized in that, If the first lens group is arranged before the light-inlet side of the folding prism, and the second lens group is arranged after the light-outlet side of the folding prism, the distance M1 from the bottom of the folding prism to the outermost point of the object-side surface of the lens closest to the object side of the first lens group, the distance M2 from the bottom of the folding prism to the bottom surface of the circuit board where the chip imaging component is located, and the total optical length M3 of the grouped telephoto lens satisfy: M1 + M2 < M3 - 2.

4. The grouped telephoto lens according to claim 1, characterized in that, The distance M4 between the intersection of the zero-field principal ray and the second reflecting surface of the folding prism and the incident optical axis satisfies: M4≥3.5mm.

5. The grouped telephoto lens according to claim 1, characterized in that, If the first lens group is arranged before the light-inlet side of the folding prism, and the second lens group is arranged after the light-outlet side of the folding prism, in the telephoto state, the distance H8a between the lens of the first lens group closest to the folding prism and the folding prism along the optical axis, and the distance H8b between the lens of the first lens group closest to the folding prism and the folding prism along the optical axis in the near-focus state, the near-focus object distance H0, and the system focal length f' of the grouped telephoto lens satisfy: ABS(H8a-H8b) / (f'*H0 / (H0-f')-f')≤ 1.

6. The grouped telephoto lens according to claim 1, characterized in that, The optical power EFX1 of the first lens group and the system focal length f' of the grouped telephoto lens satisfy: EFX1 / f' < 1.

7. The grouped telephoto lens according to claim 1, characterized in that, The second lens group includes a fourth lens, and the equivalent thickness H9 of the reflecting prism and the center thickness H11 of the fourth lens satisfy: 0.01≤H11 / H9≤0.

1.

8. The grouped telephoto lens according to claim 1, characterized in that, The equivalent thickness H9 of the reflecting prism and the system focal length f' of the clustered telephoto lens satisfy: 0.25≤f' / H9≤1.

2.

9. The grouped telephoto lens according to claim 1, characterized in that, The second lens group includes a fourth lens, the focal length of which, f4, and the system focal length, f', of the grouped telephoto lens satisfy: -5 ≤ f4 / f' ≤ 0.

10. The grouped telephoto lens according to claim 1, characterized in that, The radius of curvature C3 of the object-side surface of the lens closest to the object in the first lens group, and the radius of curvature C12 of the object-side surface of the second lens group satisfy: 0.5≤C3 / C12≤1.8.

Images