Telephoto lens

Abstract

The invention discloses a telephoto lens. The telephoto lens sequentially comprises a lens assembly and a special-shaped prism from an object side to an image side, the special-shaped prism comprises an incident surface, a first reflecting surface, a second reflecting surface, a third reflecting surface, an emergent surface and a connecting surface; one side of the emergent surface intersects with the third reflecting surface, the other opposite side of the emergent surface is located on the side, away from the third reflecting surface, of the second reflecting surface, the connecting surface intersects with the second reflecting surface to form a first intersecting line, the connecting surface intersects with the other opposite side of the emergent surface to form a second intersecting line, and the third reflecting surface intersects with the emergent surface to form a third intersecting line. The connecting surface is a single continuous surface or a composite surface consisting of a first sub-surface and a second sub-surface; an optical path compensation space is formed between the connecting surface and the third reflecting surface; the special-shaped prism is of an integrally-formed structure or is formed by gluing at least two sub-prisms. According to the invention, long focal length can be realized under the condition of small thickness, the structure is simple, and the size is small.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical imaging technology, in particular to a long-focus lens. BACKGROUND

[0002] With the development of the multi-function of various electronic products, the camera function becomes a necessary function of many electronic products, such as smart phones, tablet computers and the like with camera function. Therefore, the lens assembly has become a necessary component of various electronic devices.

[0003] However, in order to realize the photography of a more distant object, the lens needs to have a longer focal length, and the longer focal length means a large optical path, resulting in a large volume of the lens, which is difficult to use in thin smart phones and other image devices. SUMMARY

[0004] In view of the above problems, the purpose of the present application is to provide a long-focus lens which can realize a long focal length in a small thickness, has a simple structure and a small volume.

[0005] The present application provides a long-focus lens, which comprises a lens assembly and a special prism from the object side to the image side; the special prism comprises an incident surface, a first reflecting surface, a second reflecting surface, a third reflecting surface, an exit surface and a connecting surface; the incident surface and the second reflecting surface are the same surface, the second reflecting surface is arranged opposite to the third reflecting surface, and the first reflecting surface is arranged opposite to the exit surface; one side of the exit surface intersects with the third reflecting surface, and the opposite side of the exit surface is located on the side of the second reflecting surface away from the third reflecting surface, the connecting surface intersects with the second reflecting surface to form a first intersection line, the connecting surface intersects with the opposite side of the exit surface to form a second intersection line, the third reflecting surface intersects with the exit surface to form a third intersection line, the connecting surface is a single continuous surface or a composite surface composed of a first sub-surface and a second sub-surface, the first sub-surface intersects with the second reflecting surface to form the first intersection line, and the second sub-surface intersects with the opposite side of the exit surface to form the second intersection line; an optical path compensation space is formed between the connecting surface and the third reflecting surface; the special prism is an integral molding structure or is composed of at least two sub-prisms; the light passing through the lens assembly is incident into the special prism from the incident surface, is reflected from the first reflecting surface to the second reflecting surface for the first time, and is reflected at least once from the second reflecting surface and the third reflecting surface in turn, respectively, and finally passes through the optical path compensation space and is emitted from the exit surface to the imaging surface of the imaging chip.

[0006] Optionally, the first reflecting surface is provided with a reflecting film.

[0007] Optionally, a distance M5 between an optical axis of the lens assembly and a center of the imaging chip and a focal length f of the telephoto lens satisfy: 0.3≤M5 / f≤1.5.

[0008] Optionally, an equivalent thickness Hp of the shaped prism and the focal length f of the telephoto lens satisfy: 0.34≤Hp / f≤2.3.

[0009] Optionally, a thickness M1 of the lens assembly and a thickness M2 of the shaped prism satisfy: 0.54≤M1 / M2≤2.43.

[0010] Optionally, an included angle θ1 between an incident surface of the shaped prism and a first reflecting surface of the shaped prism satisfy: 22°≤θ1≤34°.

[0011] Optionally, the connecting surface is a plane, and an included angle θ2 between the connecting surface and a 0.6 field of view positive field edge light ray satisfy: 2°≤θ2≤35°.

[0012] Optionally, a distance M3 between the lens assembly and the shaped prism satisfy: 0.1mm≤M3.

[0013] Optionally, a distance M4 between the shaped prism and the imaging chip and an aperture FNO of the telephoto lens satisfy: 0.2≤M4 / FNO≤2.2.

[0014] Optionally, at a position adjacent to an intersection of the connecting surface and the second reflecting surface, a distance M6 between an intersection point of a 0.6 field of view negative field edge light ray and the second reflecting surface and a virtual intersection point between a 0.6 field of view positive field edge light ray and an extension surface of the second reflecting surface satisfy: 0.22mm≤M6≤3.89mm.

[0015] Optionally, a distance M7 between a reflection point of a 0 field of view chief ray on the first reflecting surface and a reflection point of the 0 field of view chief ray on the third reflecting surface to the exit surface satisfy: 1.74≤M7 / M2≤4.1.

[0016] Optionally, a distance M8 between a reflection point of a 0.6 field of view chief ray on the third reflecting surface to the exit surface and an intersection position of the exit surface and the third reflecting surface satisfy: 0.2mm≤M8.

[0017] Optionally, the lens assembly includes a plurality of lenses, a lens closest to an object side in the plurality of lenses is a first lens, and a focal length f1 of the first lens and a focal length f of the telephoto lens satisfy: 0.14≤f1 / f≤2.

[0018] Optionally, the lens assembly comprises a plurality of lenses, and the first two lenses arranged in sequence from the object side to the image side are a first lens and a second lens respectively, and a relationship between a focal length f1 of the first lens and a focal length f2 of the second lens satisfies: 2.08≤|f2| / f1.

[0019] Optionally, the special-shaped prism is a cemented prism, and one side of a cemented surface in the middle of the special-shaped prism is arranged at the intersection of the connecting surface and the second reflecting surface, and the other side is arranged at the intersection of the exit surface and the third reflecting surface, or one side of the cemented surface in the middle of the special-shaped prism is arranged at the intersection of the connecting surface and the second reflecting surface, and the other side is arranged at the intersection of the second reflecting surface after extension and the exit surface.

[0020] Optionally, the special-shaped prism comprises a first sub-prism and a second sub-prism which are cemented, the first sub-prism comprises the second reflecting surface and the third reflecting surface, the second sub-prism comprises the connecting surface and the exit surface, the first sub-prism and the second sub-prism are connected through a first cemented surface, one side of the first cemented surface coincides with the first intersection line, and the other side of the first cemented surface coincides with the third intersection line, or the special-shaped prism comprises a third sub-prism and a fourth sub-prism which are cemented, the third sub-prism comprises the second reflecting surface, the third reflecting surface and a first part of the exit surface, the fourth sub-prism comprises the connecting surface and a second part of the exit surface, the first part and the second part of the exit surface intersect to form a fourth intersection line, the fourth intersection line is located at the intersection of the extension of the second reflecting surface and the exit surface, the third sub-prism and the fourth sub-prism are connected through a second cemented surface, one side of the second cemented surface coincides with the first intersection line, and the other side of the second cemented surface coincides with the fourth intersection line.

[0021] Optionally, the special-shaped prism comprises a first sub-prism and a second sub-prism which are cemented, the first sub-prism comprises the second reflecting surface and the third reflecting surface, the second sub-prism comprises the connecting surface and the exit surface, the first sub-prism and the second sub-prism are connected through a first cemented surface, one side of the first cemented surface coincides with the first intersection line, and the other side of the first cemented surface coincides with the third intersection line, and an included angle θ3 between a 0.6 field of view negative field of view edge light and the first cemented surface satisfies: 1°≤θ3.

[0022] Optionally, the first reflecting surface of the special-shaped prism is provided with vignetting.

[0023] Optionally, the exit surface of the special-shaped prism is a plane, a spherical surface or an aspherical surface.

[0024] The long-focus lens comprises a lens assembly and a special-shaped prism from an object side to an image side. The lens assembly can adopt at least one positive lens to converge light, which is beneficial to realize long-focus shooting, can reduce the size of the lens, realize miniaturization, and is also beneficial to realize a large-aperture design. The back focal length of the lens is folded inside the special-shaped prism, so that light can reach the imaging surface of the imaging chip through a small optical path after being emitted from the special-shaped prism, the back focal length of the lens is correspondingly shortened, and the long focal length and miniaturization of the lens can be realized in a small thickness. The special-shaped prism is provided with a connecting surface for connecting the second reflecting surface and the exit surface. Because one side of the exit surface is located on the side of the second reflecting surface away from the third reflecting surface, the connecting surface protrudes outward relative to the second reflecting surface. The connecting surface and the third reflecting surface form an optical path compensation space, so that the special-shaped prism can be arranged in a smaller thickness between the incident surface and the third reflecting surface, and the light path difference of the light after multiple reflections in the smaller thickness of the special-shaped prism can be compensated when passing through the optical path compensation space, so that imaging on the imaging surface is ensured. Therefore, the special-shaped prism can be arranged in a smaller thickness between the incident surface and the third reflecting surface by arranging the connecting surface, so as to further reduce the local thickness of the special-shaped prism and facilitate the miniaturization of the lens. Therefore, the long-focus lens can realize long focal length, simple structure and small size by using the lens assembly and the special-shaped prism. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0026] Figure 1 A structural schematic diagram of a long-focus lens according to an embodiment of the present application is shown.

[0027] Figure 2 is Figure 1 a size schematic diagram.

[0028] Figure 3 is Figure 1 a size schematic diagram.

[0029] Figure 4 is Figure 1 a size schematic diagram.

[0030] Figure 5 is Figure 1 a size schematic diagram.

[0031] Figure 6 isFigure 1 A schematic diagram of a glued structure.

[0032] Figure 7 yes Figure 1 Another schematic diagram of the glued structure.

[0033] Figure 8 yes Figure 1 A schematic diagram of one dimension.

[0034] Figure 9 yes Figure 1 A schematic diagram of its specific structure.

[0035] Figure 10 A schematic diagram of the structure of a telephoto lens according to Embodiment 1 of this application is shown.

[0036] Figures 11 to 13 The MTF curve, distortion diagram, and relative illumination versus Y field of view diagram of the telephoto lens of Example 1 are shown respectively.

[0037] Figure 14 A schematic diagram of the structure of a telephoto lens according to Embodiment 2 of this application is shown.

[0038] Figures 15 to 17 The MTF curve, distortion diagram, and relative illumination versus Y field of view diagram of the telephoto lens of Example 2 are shown respectively.

[0039] Figure 18 A schematic diagram of the structure of a telephoto lens according to Embodiment 3 of this application is shown.

[0040] Figures 19 to 21 The MTF curve, distortion diagram, and relative illumination versus Y field of view diagram of the telephoto lens of Example 3 are shown respectively.

[0041] Figure 22 A schematic diagram of the structure of a telephoto lens according to Embodiment 4 of this application is shown.

[0042] Figures 23 to 25 The MTF curve, distortion diagram, and relative illumination versus Y field of view diagram of the telephoto lens of Example 4 are shown respectively.

[0043] Figure 26 A schematic diagram of the structure of a telephoto lens according to Embodiment 5 of this application is shown.

[0044] Figures 27 to 29 The MTF curve, distortion diagram, and relative illumination versus Y field of view diagram of the telephoto lens of Example 5 are shown respectively.

[0045] Figure 30 A schematic diagram of the structure of a telephoto lens according to Embodiment 6 of this application is shown.

[0046] Figures 31 to 33MTF curves, distortion, and relative illumination vs. Y field of view for the long lens of Example 6 are shown. DETAILED DESCRIPTION

[0047] The foregoing and other technical features, aspects, and effects of the present application will become better understood from the following detailed description of the preferred embodiments with reference to the accompanying drawings. The attached drawings are provided to illustrate preferred embodiments of the present application and to provide an understanding of the principles of the present application. The present application should not be considered limited to the preferred embodiments set forth in the figures, but include all solutions that are considered equivalent in scope to the technical features described in the claims. In the drawings:

[0048] It is to be understood that the terms "first", "second", "third", and "fourth" and the like in the description and in the claims are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. The terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0049] In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for the purpose of illustration. Specifically, the shape of the spherical surface shown in the drawings is shown by way of example. That is, the shape of the spherical surface is not limited to the shape of the spherical surface shown in the drawings. The drawings are merely examples and are not drawn to scale.

[0050] In this document, the paraxial region refers to a region near the optical axis. If a lens surface is convex and the position of the convex surface is not specified, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the position of the concave surface is not specified, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is referred to as the object side surface of the lens, and the surface of each lens closest to the image plane is referred to as the image side surface of the lens.

[0051] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0052] The features, principles, and other aspects of the present application are described in detail below.

[0053] Figure 1 A structural schematic diagram of a long lens according to an embodiment of the present application is shown.

[0054] According to the long-focus lens of the exemplary embodiment of the present application, the long-focus lens comprises, in order from the object side to the image side, a lens assembly 10 and a special prism P1; the special prism P1 comprises an incident surface S1, a first reflecting surface S2, a second reflecting surface S3, a third reflecting surface S4, an exit surface S5 and a connecting surface S6; the incident surface S1 and the second reflecting surface S3 are the same surface, the second reflecting surface S3 is arranged opposite to the third reflecting surface S4, and the first reflecting surface S2 is arranged opposite to the exit surface S5; one side of the exit surface S5 intersects the third reflecting surface S4, and the opposite side of the exit surface S5 is located on the side of the second reflecting surface S3 away from the third reflecting surface S4; the connecting surface S6 intersects the second reflecting surface S3 to form a first intersection line E1, the connecting surface S6 intersects the opposite side of the exit surface S5 to form a second intersection line E2, the third reflecting surface S4 intersects the exit surface S5 to form a third intersection line E3, the connecting surface S6 is a single continuous surface or a composite surface composed of a first sub-surface and a second sub-surface, the first sub-surface intersects the second reflecting surface S3 to form the first intersection line E1, and the second sub-surface intersects the opposite side of the exit surface S5 to form the second intersection line E2; an optical path compensation space is formed between the connecting surface S6 and the third reflecting surface S4. The light emitted by the lens assembly 10 is incident into the special prism P1 from the incident surface S1, is reflected by the first reflecting surface S2 for the first time to the second reflecting surface S3, and is reflected by the second reflecting surface S3 and the third reflecting surface S4 at least once in turn, respectively, and finally passes through the optical path compensation space and is emitted from the exit surface S5 to the imaging surface IMG of the imaging chip.

[0055] In the embodiment, the lens assembly 10 can adopt at least one positive lens to converge light, which is beneficial to realize long-focus shooting, and can reduce the size of the lens, realize miniaturization, and is also beneficial to realize a large aperture design; the rear focal length of the lens is folded inside the shaped prism P1, so that the light can reach the imaging surface IMG of the imaging chip through a smaller optical path after being emitted from the shaped prism P1, the rear focal length of the lens is correspondingly shortened, and then long focal length and miniaturization of the lens can be realized in a smaller thickness. The shaped prism P1 is provided with a connecting surface S6 for connecting the second reflecting surface S3 and the exit surface S5, because one side of the exit surface S5 is located on the side of the second reflecting surface S3 away from the third reflecting surface S4, the connecting surface S6 protrudes outward relative to the second reflecting surface S3, and the connecting surface S6 and the third reflecting surface S4 form an optical path compensation space; then the shaped prism P1 can be arranged between the incident surface S1 and the third reflecting surface S4 in a smaller thickness, and the light is reflected multiple times in the smaller thickness of the shaped prism P1, and the optical path difference after the light is reflected multiple times can be compensated when the light passes through the optical path compensation space, so that imaging on the imaging surface IMG is ensured, therefore, the shaped prism P1 is provided with the connecting surface S6, so that the incident surface S1 and the third reflecting surface S4 can be arranged in a smaller thickness, the local thickness of the shaped prism P1 can be further reduced, and miniaturization of the lens is beneficial. Therefore, the long-focus lens can realize long focal length in a smaller thickness through the lens assembly 10 and the shaped prism P1, and has a simple structure and small size.

[0056] In a specific example embodiment, according to the long-focus lens of the present application, the light passing through the lens assembly 10 is emitted from the incident surface S1 to the shaped prism P1, is reflected for the first time to the second reflecting surface S3 through the first reflecting surface S2, is reflected for the second time to the third reflecting surface S4 through the second reflecting surface S3, is reflected for the third time through the third reflecting surface S4, and finally passes through the optical path compensation space and is emitted from the exit surface S5 to the imaging surface IMG of the imaging chip. Among them, the second reflecting surface S3 and the third reflecting surface S4 only reflect once. However, the present application is not limited thereto, and the second reflecting surface S3 and the third reflecting surface S4 can reflect twice or more times, for example, the second reflecting surface S3 and the third reflecting surface S4 can reflect twice, then the light passing through the lens assembly 10 is emitted from the incident surface S1 to the shaped prism P1, is reflected for the first time to the second reflecting surface S3 through the first reflecting surface S2, is reflected for the second time to the third reflecting surface S4 through the second reflecting surface S3, is reflected for the third time to the second reflecting surface S3 through the third reflecting surface S4, is reflected for the fourth time to the third reflecting surface S4 through the second reflecting surface S3, is reflected for the fifth time through the third reflecting surface S4, and finally passes through the optical path compensation space and is emitted from the exit surface S5 to the imaging surface IMG of the imaging chip.

[0057] In an exemplary embodiment, the telephoto lens according to this application has a connecting surface S6 that is a single continuous surface or a composite surface composed of a first sub-surface and a second sub-surface. The single continuous surface includes a plane, a sphere, an aspherical surface, and a freeform surface. Preferably, the single continuous surface is a plane. The first sub-surface and the second sub-surface in the composite surface are both single continuous surfaces, such as a plane, a sphere, an aspherical surface, or a freeform surface. Preferably, the first sub-surface and the second sub-surface are both planes. The first sub-surface and the second sub-surface can intersect to form an intersection line or be connected through a transition region such as a rounded corner. Preferably, the second sub-surface can be parallel to the second reflecting surface.

[0058] In an exemplary embodiment, the telephoto lens according to this application has a reflective film on the first reflective surface S2. This ensures that the light is completely reflected when it is reflected by the first reflective surface S2, reducing the risk of the light being refracted out of the irregular prism P1 when it passes through the first reflective surface S2. This enhances the transmittance of the light from the incident surface S1 to the exit surface S5, reduces the diffraction stray light caused by the surface roughness or edge discontinuity of the first reflective surface S2, and avoids the image becoming foggy due to diffraction stray light.

[0059] In an exemplary implementation, such as Figure 2 As shown, the telephoto lens according to this application satisfies 22°≤θ1≤34°; wherein, the angle between the incident surface S1 and the first reflecting surface S2 of the irregular prism P1 is θ1. By satisfying 22°≤θ1≤34° and limiting the angle θ1 between the incident surface S1 and the first reflecting surface S2 of the irregular prism P1, the optical path direction of the light entering the irregular prism P1 can be controlled, causing the light to be reflected and folded multiple times. This increases the optical path, enabling a telephoto, large aperture, large target surface, and miniaturized design. It also reduces stray light in the telephoto lens and improves its imaging quality. Furthermore, it helps ensure that when light is reflected at least once by the second reflecting surface S3 and the third reflecting surface S4, all reflections are total internal reflections, reducing the risk of light being refracted out of the irregular prism P1 when passing through the second reflecting surface S3 and the third reflecting surface S4, and enhancing the transmittance of light from the incident surface S1 to the exit surface S5.

[0060] In an example embodiment, the long-focus lens according to the present application can be provided with a chamfer or a round corner at the intersection of the incident surface S1 and the first reflection surface S2, i.e. at the included angle θ1, and the tangent of the chamfer can be perpendicular to the incident surface S1. The chamfer or the round corner can reduce the lateral length of the incident surface S1 of the special-shaped prism P1, and further reduce the overall lateral length of the special-shaped prism, thereby saving the internal space of the lens module, improving the reliability of the module, and reducing stray light. However, the present application is not limited thereto, and other surfaces of the special-shaped prism P1 can be chamfered or rounded as needed to save the internal space of the lens module, improve the manufacturing yield of the prism, improve the overall reliability, and have a certain effect of preventing stray light.

[0061] In an example embodiment, the long-focus lens according to the present application further comprises a stop STO. Preferably, the stop STO can be arranged on the object side of the first lens L1. However, the present application is not limited thereto, and the stop STO can be arranged between two adjacent lenses.

[0062] In an example embodiment, the long-focus lens according to the present application increases vignetting on the first reflection surface S2 of the special-shaped prism P1, i.e. the part of the light beam of the large field of view is blocked by the frame or the stop STO, so that the first reflection surface S2 is provided with an appropriate area surface that satisfies the reflection of the edge light of the large field of view, and the distance between the incident surface S1 and the third reflection surface S4 is correspondingly reduced, i.e. the thickness of the special-shaped prism P1 is reduced, and further the overall height of the lens is reduced, so that the lens has a small size.

[0063] In an example embodiment, the long-focus lens according to the present application further comprises a filter IR for correcting color deviation and / or a protective glass for protecting the photosensitive elements on the imaging surface IMG. In an example embodiment, the filter IR of the long-focus lens according to the present application can be arranged between the exit surface S5 of the special-shaped prism P1 and the imaging chip, but the present application is not limited thereto, and the filter IR can also be arranged at other positions, such as between the lens assembly 10 and the incident surface S1 of the special-shaped prism P1.

[0064] In an example embodiment, the long-focus lens according to the present application, the object side or the image side of the filter IR is spherical or aspherical, which can be used to correct aberration, further improve the imaging quality, and can reduce the number of lenses, thereby reducing the overall height of the lens and realizing the lens with a small size.

[0065] In an example embodiment, as Figure 2As shown, the long-focus lens according to the present application can satisfy 0.3≤M5 / f≤1.5; wherein the distance between the optical axis of the lens assembly 10 and the center of the imaging chip is M5, and the focal length of the long-focus lens is f. Satisfying 0.3≤M5 / f≤1.5, by controlling the ratio range of the distance M5 between the optical axis of the lens assembly 10 and the center of the imaging chip and the focal length f of the long-focus lens, the length of the special prism P1 can be controlled, and the lens can have a small volume.

[0066] In an example embodiment, the long-focus lens according to the present application can satisfy 0.34≤Hp / f≤2.3; wherein the equivalent thickness of the special prism P1 is Hp, and the focal length of the long-focus lens is f. Satisfying 0.34≤Hp / f≤2.3, by controlling the ratio range of the equivalent thickness Hp of the special prism P1 and the focal length f of the long-focus lens, the length of the special prism P1 can be controlled within a certain range, which is beneficial to reduce the volume and realize the lens with a small volume.

[0067] In an example embodiment, as shown in Figure 2 the long-focus lens according to the present application can satisfy 0.54≤M1 / M2≤2.43; wherein the thickness of the lens assembly 10, i.e. the height of the lens assembly 10 in the direction of the optical axis, is M1, and the thickness of the special prism P1, i.e. the distance between the second reflecting surface S3 and the third reflecting surface S4, is M2. Satisfying 0.54≤M1 / M2≤2.43, by controlling the ratio range of the thickness M1 of the lens assembly 10 and the thickness M2 of the special prism P1, the system structure can be balanced, and local overheight can be avoided.

[0068] In an example embodiment, as shown in Figure 2 the long-focus lens according to the present application can satisfy 0.1mm≤M3; wherein the distance between the lens assembly 10 and the special prism P1 is M3. Satisfying 0.1mm≤M3, by controlling the value range of the distance M3 between the lens assembly 10 and the special prism P1, the lens assembly 10 can be prevented from colliding with the special prism P1.

[0069] In an example embodiment, as shown in Figure 2 the long-focus lens according to the present application can satisfy 0.2≤M4 / FNO≤2.2; wherein the distance between the special prism P1 and the imaging chip is M4, and the aperture of the long-focus lens is FNO. Satisfying 0.2≤M4 / FNO≤2.2, by controlling the ratio range of the distance M4 between the special prism P1 and the imaging chip and the aperture FNO of the long-focus lens, the imaging can be prevented from being dirty.

[0070] In an example embodiment, as shown in Figure 3As shown, the long-focus lens according to the present application can satisfy 2°≤θ2≤35°; wherein the connecting surface S6 is a plane, and the included angle between the connecting surface S6 and the 0.6 field of view positive field edge light is θ2. Satisfying 2°≤θ2≤35°, by controlling the value range of the included angle θ2 between the connecting surface S6 and the 0.6 field of view positive field edge light, the connecting surface S6 can maintain a smaller included angle with the 0.6 field of view positive field edge light, which helps to reduce the volume of the special prism P1 and realize the small volume of the lens. In other embodiments, when the connecting surface S6 is a composite surface composed of a first sub-surface and a second sub-surface, the included angle between the first sub-surface in the connecting surface S6 and the 0.6 field of view positive field edge light can also be set to θ2, satisfying 2°≤θ2≤35°, which helps to reduce the volume of the special prism P1 and realize the small volume of the lens.

[0071] In an example embodiment, as shown in Figure 3 As shown, the long-focus lens according to the present application can satisfy 0.22mm≤M6≤3.89mm; wherein, at the intersection adjacent to the connecting surface S6 and the second reflecting surface S3, the intersection point between the 0.6 field of view negative field edge light and the second reflecting surface S3, to the virtual intersection point between the 0.6 field of view positive field edge light and the extension of the second reflecting surface S3, the distance is M6. Satisfying 0.22mm≤M6≤3.89mm, by controlling the value range of the distance M6 between the intersection point between the 0.6 field of view negative field edge light and the second reflecting surface S3, to the virtual intersection point between the 0.6 field of view positive field edge light and the extension of the second reflecting surface S3 at the intersection adjacent to the connecting surface S6 and the second reflecting surface S3, the area of the reflecting surface can be avoided to be insufficient to cause light overflow due to process tolerance.

[0072] In an example embodiment, as shown in Figure 2 and Figure 4 As shown, the long-focus lens according to the present application can satisfy 1.74≤M7 / M2≤4.1; wherein the distance of the 0 field of view chief ray from the reflection point on the first reflecting surface S2 to the reflection point on the third reflecting surface S4 to the exit surface S5 is M7, and the thickness of the special prism P1 is M2. Satisfying 1.74≤M7 / M2≤4.1, by controlling the ratio range of the distance M7 of the 0 field of view chief ray from the reflection point on the first reflecting surface S2 to the reflection point on the third reflecting surface S4 to the exit surface S5 and the thickness M2 of the special prism P1, the length of the special prism P1 can be controlled, and the small volume of the lens can be realized.

[0073] In an example embodiment, as shown in Figure 5As shown, the long-focus lens according to the present application can satisfy 0.2mm≤M8; wherein the 0.6 field of view chief ray is reflected by the third reflecting surface S4 to the reflection point of the exit surface S5, and the distance from the reflection point to the intersection of the exit surface S5 and the third reflecting surface S4 is M8. Satisfying 0.2mm≤M8, by controlling the distance M8 from the reflection point of the 0.6 field of view chief ray reflected by the third reflecting surface S4 to the exit surface S5 to the intersection of the exit surface S5 and the third reflecting surface S4, the value range of M8 is controlled, so as to avoid the area of the reflecting surface being insufficient to cause full reflection and light overflow due to process tolerance.

[0074] In an example embodiment, the long-focus lens according to the present application can satisfy 0.14≤f1 / f≤2; wherein the lens assembly 10 includes a plurality of lenses, the lens closest to the object side in the plurality of lenses is the first lens L1, the focal length of the first lens L1 is f1, and the focal length of the long-focus lens is f. Satisfying 0.14≤f1 / f≤2, by controlling the ratio range of the focal length f1 of the first lens L1 to the focal length f of the long-focus lens, the spherical aberration is corrected, and the imaging quality is improved.

[0075] In an example embodiment, the long-focus lens according to the present application can satisfy 2.08≤|f2| / f1; wherein the lens assembly 10 includes a plurality of lenses, the first two lenses arranged in order from the object side to the image side in the plurality of lenses are the first lens L1 and the second lens L2, respectively, the focal length of the first lens L1 is f1, and the focal length of the second lens L2 is f2. Satisfying 2.08≤|f2| / f1, by controlling the ratio range of the absolute value of the focal length f2 of the second lens L2 to the focal length f1 of the first lens L1, the chromatic aberration is corrected, and the imaging quality is improved.

[0076] In an example embodiment, as shown, Figure 6 The special-shaped prism P1 includes a first sub-prism P11 and a second sub-prism P12 that are glued together, the first sub-prism P11 includes a second reflecting surface S3 and a third reflecting surface S4, the second sub-prism P12 includes a connecting surface S6 and an exit surface S5, the first sub-prism P11 and the second sub-prism P12 are connected through a first gluing surface S7, one side of the first gluing surface S7 coincides with the first intersection line E1, and the other side of the first gluing surface S7 coincides with the third intersection line E3; or, as shown, Figure 7As shown, the special-shaped prism P1 includes a third sub-prism P13 and a fourth sub-prism P14 which are glued together, the third sub-prism P13 includes the second reflecting surface S3, the third reflecting surface S4 and a first part of the exit surface S5, the fourth sub-prism P14 includes the connecting surface S6 and a second part of the exit surface S5, the first part and the second part of the exit surface S5 intersect to form a fourth intersection line E4, the fourth intersection line E4 is located at the intersection of the extension of the second reflecting surface S3 and the exit surface S5, the third sub-prism P13 and the fourth sub-prism P14 are connected through a second glue surface S8, one side of the second glue surface S8 coincides with the first intersection line E1, and the other side of the second glue surface S8 coincides with the fourth intersection line E4.

[0077] In an example embodiment, as shown, Figure 8 According to the long-focus lens of the present application, 1°≤θ3 can be met; wherein the special-shaped prism P1 includes a first sub-prism P11 and a second sub-prism P12 which are glued together, the first sub-prism P11 includes the second reflecting surface S3 and the third reflecting surface S4, the second sub-prism P12 includes the connecting surface S6 and the exit surface S5, the first sub-prism P11 and the second sub-prism P12 are connected through a first glue surface S7, one side of the first glue surface S7 coincides with the first intersection line E1, the other side of the first glue surface S7 coincides with the third intersection line E3, and the included angle between the 0.6 field of view negative field edge light and the first glue surface S7 is θ3. By controlling the value range of the included angle θ3 between the 0.6 field of view negative field edge light and the glue surface in the middle of the special-shaped prism P1, stray light caused by the glue surface can be avoided.

[0078] In an example embodiment, according to the long-focus lens of the present application, the entrance surface S1 or the exit surface S5 of the special-shaped prism P1 is a plane, a spherical surface or an aspherical surface, preferably, the entrance surface S1 or the exit surface S5 of the special-shaped prism P1 is set as a spherical surface or an aspherical surface, which can be used to correct aberration, further improve imaging quality, and reduce the number of lenses, thereby reducing the overall height of the lens and realizing a small-size lens. In one example embodiment, the exit surface S5 of the special-shaped prism P1 is a plane, a spherical surface or an aspherical surface; optionally, as shown, Figure 9 the exit surface S5 of the special-shaped prism P1 is an aspherical surface.

[0079] Based on the same inventive concept, the electronic device according to the example embodiment of the present application includes the long-focus lens described above. The electronic device can be, but is not limited to, a smartphone, a tablet computer, a notebook computer, a gimbal shooting device, a monitoring camera, a vehicle-mounted monitoring device and other imaging devices. The implementation of the electronic device can refer to the embodiments of the long-focus lens, and the repeated parts will not be described again.

[0080] The specific embodiments of the long-focus lens applicable to the above-described embodiments will be further described below with reference to the accompanying drawings.

[0081] Example 1 The following refers to Figure 10 A long-focus lens according to Embodiment 1 of the present application is described. Figure 10 A structural schematic diagram of a long-focus lens according to Embodiment 1 of the present application is shown.

[0082] As Figure 10 shown, the long-focus lens comprises, in order from the object side to the image side, a lens assembly 10 and a special prism P1; the special prism P1 comprises an incident surface S1, a first reflecting surface S2, a second reflecting surface S3, a third reflecting surface S4, an exit surface S5, and a connecting surface S6; the incident surface S1 and the second reflecting surface S3 are the same surface, the second reflecting surface S3 is oppositely arranged with the third reflecting surface S4, and the first reflecting surface S2 is oppositely arranged with the exit surface S5; one side of the exit surface S5 intersects the third reflecting surface S4, and the other side of the exit surface S5 is located on the side of the second reflecting surface S3 away from the third reflecting surface S4; the connecting surface S6 intersects the second reflecting surface S3 to form a first intersection line E1, the connecting surface S6 intersects the opposite side of the exit surface S5 to form a second intersection line E2, and the third reflecting surface S4 intersects the exit surface S5 to form a third intersection line E3; the connecting surface S6 is a single continuous surface, for example, a plane, and a light path compensation space is formed between the connecting surface S6 and the third reflecting surface S4. The lens assembly 10 comprises a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4. A stop STO can be arranged on the object side surface of the first lens L1. A filter IR can be arranged between the exit surface S5 of the special prism P1 and an imaging chip.

[0083] The following refers to Figure 10 and Table 1, the first lens L1 has positive focal power, the object side surface thereof is a convex surface, and the image side surface thereof is a convex surface. The second lens L2 has negative focal power, the object side surface thereof is a concave surface, and the image side surface thereof is a concave surface. The third lens L3 has negative focal power, the object side surface thereof is a concave surface, and the image side surface thereof is a concave surface. The fourth lens L4 has positive focal power, the object side surface thereof is a convex surface, and the image side surface thereof is a convex surface. The incident surface S1 and the exit surface S5 of the special prism P1 are both planes. The filter IR has an object side surface and an image side surface, and both the object side surface and the image side surface are planes. Light rays can pass through the lens assembly 10 and the special prism P1 in order, specifically: the stop STO, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the special prism P1, and the filter IR, and finally form an image on the imaging surface IMG of the imaging chip; wherein the light rays passing through the lens assembly 10 are incident from the incident surface S1 to the special prism P1, undergo a first reflection at the first reflecting surface S2 to the second reflecting surface S3, and then undergo a first reflection at the second reflecting surface S3 and a first reflection at the third reflecting surface S4 in turn, finally pass through the light path compensation space and exit from the exit surface S5 to the imaging surface IMG of the imaging chip.

[0084] Table 1 shows a basic parameter table of the long-focus lens of Example 1, wherein the units of the radius of curvature, the interval / thickness, and the focal length are all millimeters (mm).

[0085] Table 1:

[0086] wherein L1-R1 represents the object side surface of the first lens L1, L1-R2 represents the image side surface of the first lens L1, L2-R1 represents the object side surface of the second lens L2, L2-R2 represents the image side surface of the second lens L2, L3-R1 represents the object side surface of the third lens L3, L3-R2 represents the image side surface of the third lens L3, L4-R1 represents the object side surface of the fourth lens L4, L4-R2 represents the image side surface of the fourth lens L4, P1-S1 represents the entrance surface S1 of the shaped prism P1, P1-S5 represents the exit surface S5 of the shaped prism P1, IR-R1 represents the object side surface of the filter IR, and IR-R2 represents the image side surface of the filter IR.

[0087] In Example 1, the object side surface and the image side surface of any one of the first lens L1 to the fourth lens L4 are all even aspheric surfaces, and the surface type of the even aspheric surface can be defined by the following formula: (1) wherein Z represents the height in the direction of the optical axis, c is the reciprocal of the surface radius, k is the conic coefficient, and r is the radial direction aperture; a represents the aspheric coefficient, a1 represents the aspheric coefficient A2, a2 represents the aspheric coefficient A4, and so on.

[0089] Table 2 shows the conic coefficient and the high-order coefficients A2, A4, A6, A8, A10, A12, A14, and A16 that can be used when the object side surface and the image side surface of the first lens L1 to the fourth lens L4 in Example 1 are even aspheric surfaces.

[0090] Table 2:

[0091] In the embodiment 1, the focal length f of the telephoto lens is 15.8 mm, the aperture FNO is 2.59, the imaging circle diameter is 8.6 mm, and the working waveband is 420~680 nm. The distance M5 between the optical axis of the lens assembly 10 and the center of the imaging chip is 11.47 mm, and the relationship between M5 and the focal length f of the telephoto lens is M5 / f =0.73, which satisfies 0.3≤M5 / f≤1.5. The equivalent thickness Hp of the shaped prism P1 is 15.40 mm, and the relationship between Hp and the focal length f of the telephoto lens is Hp / f =0.97, which satisfies 0.34≤Hp / f≤2.3. The thickness M1 of the lens assembly 10 is 4.72 mm, the thickness M2 of the shaped prism P1 is 3.50 mm, and the relationship between M1 and M2 is M1 / M2 =1.35, which satisfies 0.54≤M1 / M2≤2.43. The included angle θ1 between the incidence face S1 of the shaped prism P1 and the first reflection face S2 of the shaped prism P1 is θ1 =26°, which satisfies 22°≤θ1≤34°. The connecting face S6 is a plane, the included angle θ2 between the connecting face S6 and the 0.6 field of view positive field edge light is θ2 =7°, which satisfies 2°≤θ2≤35°. The distance M3 between the lens assembly 10 and the shaped prism P1 is M3 =0.28 mm, which satisfies 0.1 mm≤M3. The distance M4 between the shaped prism P1 and the imaging chip is 1.67 mm, and the relationship between M4 and the aperture FNO of the telephoto lens is M4 / FNO =0.64, which satisfies 0.2≤M4 / FNO≤2.2. At the intersection between the connecting face S6 and the second reflection face S3, the intersection point between the 0.6 field of view negative field edge light and the second reflection face S3, and the virtual intersection point between the 0.6 field of view positive field edge light and the extension plane of the second reflection face S3, the distance M6 is M6 =0.29 mm, which satisfies 0.22 mm≤M6≤3.89 mm. The distance M7 from the reflection point of the 0 field of view chief ray on the first reflection face S2 to the reflection point of the 0 field of view chief ray on the third reflection face S4 to the exit face S5 is 7.16 mm, and the relationship between M7 and the thickness M2 of the shaped prism P1 is M7 / M2 =2.05, which satisfies 1.74≤M7 / M2≤4.1. The distance M8 from the reflection point of the 0.6 field of view chief ray on the third reflection face S4 to the exit face S5 to the intersection point between the exit face S5 and the third reflection face S4 is M8 =1.04 mm, which satisfies 0.2 mm≤M8. The focal length f1 of the first lens L1 and the focal length f of the telephoto lens satisfy f1 / f =0.40, which satisfies 0.14≤f1 / f≤2. The focal length f1 of the first lens L1 and the focal length f2 of the second lens L2 satisfy |f2| / f1 =14.43, which satisfies 2.08≤|f2| / f1.

[0092] Figure 11The MTF curve of the long-focus lens of embodiment 1 is shown, and the MTF (Modulation Transfer Function) curve shows the transmission of the imaging system to the image details (i.e. image contrast) of different spatial frequencies, and the OTF modulus is greater than 0.5 at a spatial frequency of 89 lp / mm, and the resolving power is good. Figure 12 The distortion diagram of the long-focus lens of embodiment 1 is shown, and the distortion is less than 2%, and the correction is good. Figure 13 The relative luminance and Y field diagram of the long-focus lens of embodiment 1 is shown, and the relative luminance is greater than 0.6, and the picture luminance is uniform. According to Figures 11 to 13 It can be seen that the long-focus lens given by embodiment 1 has good resolving power, good correction, and uniform picture luminance, and can achieve good imaging quality.

[0093] Example 2 The following refers to Figure 14 The long-focus lens according to embodiment 2 of the present application is described. Figure 14 The structural schematic diagram of the long-focus lens according to embodiment 2 of the present application is shown.

[0094] As Figure 14 shown, the long-focus lens sequentially includes a lens assembly 10 and a special-shaped prism P1 from the object side to the image side; the special-shaped prism P1 includes an incident surface S1, a first reflecting surface S2, a second reflecting surface S3, a third reflecting surface S4, an exit surface S5, and a connecting surface S6; the incident surface S1 and the second reflecting surface S3 are the same surface, the second reflecting surface S3 is oppositely arranged with the third reflecting surface S4, and the first reflecting surface S2 is oppositely arranged with the exit surface S5; one side of the exit surface S5 intersects the third reflecting surface S4, and the other side of the exit surface S5 is located on the side of the second reflecting surface S3 away from the third reflecting surface S4, the connecting surface S6 intersects the second reflecting surface S3 to form a first intersection line E1, the connecting surface S6 intersects the opposite side of the exit surface S5 to form a second intersection line E2, the third reflecting surface S4 intersects the exit surface S5 to form a third intersection line E3, and the connecting surface S6 is a single continuous surface, for example, a plane, and the connecting surface S6 and the third reflecting surface S4 form an optical path compensation space. The lens assembly 10 includes a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4. A stop STO can be arranged on the object side surface of the first lens L1. A filter IR can be arranged between the exit surface S5 of the special-shaped prism P1 and the imaging chip.

[0095] The following refers to Figure 14and Table 3, the first lens L1 has positive refractive power, the object side surface thereof is convex, and the image side surface thereof is concave. The second lens L2 has negative refractive power, the object side surface thereof is convex, and the image side surface thereof is concave. The third lens L3 has negative refractive power, the object side surface thereof is concave, and the image side surface thereof is concave. The fourth lens L4 has positive refractive power, the object side surface thereof is convex, and the image side surface thereof is concave. The incident surface S1 and the exit surface S5 of the special prism P1 are both planes. The filter IR has an object side surface and an image side surface, and both the object side surface and the image side surface are planes. The light rays can pass through the lens assembly 10 and the special prism P1 in sequence, specifically: the light stop STO, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the special prism P1 and the filter IR, and finally form an image on the imaging surface IMG of the imaging chip; wherein the light rays passing through the lens assembly 10 are incident from the incident surface S1 to the special prism P1, are reflected for the first time to the second reflecting surface S3 through the first reflecting surface S2, are reflected once in turn through the second reflecting surface S3 and the third reflecting surface S4 respectively, and finally pass through the optical path compensation space and are emitted from the exit surface S5 to the imaging surface IMG of the imaging chip.

[0096] Table 3 shows the basic parameter table of the long-focus lens of Example 2, wherein the units of the curvature radius, the interval / thickness and the focal length are all millimeters (mm).

[0097] Table 3:

[0098] Table 4 shows the conic coefficients and high-order coefficients A2, A4, A6, A8, A10, A12, A14 and A16 when the object side surface and the image side surface of the first lens L1 to the fourth lens L4 in Example 2 are even aspheric surfaces. Wherein the surface type of each even aspheric surface can be defined by the formula (1) given in the above Example 1.

[0099] Table 4:

[0100] In the embodiment 2, the focal length f of the telephoto lens is 23.49 mm, the aperture FNO is 2.6, the imaging circle diameter is 13.76 mm, and the working waveband is 420~680 nm. The distance M5 between the optical axis of the lens assembly 10 and the center of the imaging chip is 17.51 mm, and the relationship between M5 and the focal length f of the telephoto lens satisfies M5 / f =0.75, which meets 0.3≤M5 / f≤1.5. The equivalent thickness Hp of the special prism P1 is 24.41 mm, and the relationship between Hp and the focal length f of the telephoto lens satisfies Hp / f =1.04, which meets 0.34≤Hp / f≤2.3. The thickness M1 of the lens assembly 10 is 5.85 mm, the thickness M2 of the special prism P1 is 5.54 mm, and the relationship between M1 and M2 satisfies M1 / M2=1.06, which meets 0.54≤M1 / M2≤2.43. The included angle θ1 between the incident surface S1 of the special prism P1 and the first reflecting surface S2 of the special prism P1 satisfies θ1=26°, which meets 22°≤θ1≤34°. The connecting surface S6 is a plane, and the included angle θ2 between the connecting surface S6 and the 0.6 field of view positive field edge light satisfies θ2=5°, which meets 2°≤θ2≤35°. The distance M3 between the lens assembly 10 and the special prism P1 satisfies M3=0.17 mm, which meets 0.1 mm≤M3. The distance M4 between the special prism P1 and the imaging chip satisfies M4 / FNO=0.65, which meets 0.2≤M4 / FNO≤2.2. At the intersection between the connecting surface S6 and the second reflecting surface S3, the intersection point between the 0.6 field of view negative field edge light and the second reflecting surface S3, and the virtual intersection point between the 0.6 field of view positive field edge light and the extension of the second reflecting surface S3, the distance M6 satisfies M6=0.63 mm, which meets 0.22 mm≤M6≤3.89 mm. The distance M7 from the reflection point of the 0 field of view chief ray on the first reflecting surface S2 to the reflection point of the 0 field of view chief ray on the third reflecting surface S4 to the exit surface S5 satisfies M7 / M2=2.05, which meets 1.74≤M7 / M2≤4.1. The distance M8 from the reflection point of the 0.6 field of view chief ray on the third reflecting surface S4 to the exit surface S5 to the intersection point of the exit surface S5 and the third reflecting surface S4 satisfies M8=1.32 mm, which meets 0.2 mm≤M8. The focal length f1 of the first lens L1 and the focal length f of the telephoto lens satisfy f1 / f =0.41, which meets 0.14≤f1 / f≤2. The relationship between the focal length f1 of the first lens L1 and the focal length f2 of the second lens L2 satisfies |f2| / f1=6.42, which meets 2.08≤|f2| / f1.

[0101] Figure 15The MTF curve of the long-focus lens of embodiment 2 is shown, and the MTF (Modulation Transfer Function) curve shows the transmission of the imaging system to the image details (i.e. image contrast) of different spatial frequencies, and the OTF module value is greater than 0.5 at a spatial frequency of 89 lp / mm, and the resolving power is good. Figure 16 The distortion diagram of the long-focus lens of embodiment 2 is shown, and the distortion is less than 2%, and the correction is good. Figure 17 The relative luminance and Y field diagram of the long-focus lens of embodiment 2 is shown, and the relative luminance is greater than 0.6, and the picture luminance is uniform. According to Figures 15 to 17 It can be seen that the long-focus lens given by embodiment 2 has good resolving power, good correction, and uniform picture luminance, and can achieve good imaging quality.

[0102] Example 3 The following refers to Figure 18 The long-focus lens according to embodiment 3 of the present application is described. Figure 18 The structural schematic diagram of the long-focus lens according to embodiment 3 of the present application is shown.

[0103] As Figure 18 shown, the long-focus lens sequentially includes a lens assembly 10 and a special-shaped prism P1 from the object side to the image side; the special-shaped prism P1 includes an incident surface S1, a first reflecting surface S2, a second reflecting surface S3, a third reflecting surface S4, an exit surface S5, and a connecting surface S6; the incident surface S1 and the second reflecting surface S3 are the same surface, the second reflecting surface S3 is oppositely arranged with the third reflecting surface S4, and the first reflecting surface S2 is oppositely arranged with the exit surface S5; one side of the exit surface S5 intersects the third reflecting surface S4, and the other side of the exit surface S5 is located on the side of the second reflecting surface S3 away from the third reflecting surface S4, the connecting surface S6 intersects the second reflecting surface S3 to form a first intersection line E1, the connecting surface S6 intersects the opposite side of the exit surface S5 to form a second intersection line E2, the third reflecting surface S4 intersects the exit surface S5 to form a third intersection line E3, and the connecting surface S6 is a single continuous surface, for example, a plane, and the connecting surface S6 and the third reflecting surface S4 form an optical path compensation space. The lens assembly 10 includes a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4. A stop STO can be arranged on the object side surface of the first lens L1. A filter IR can be arranged between the exit surface S5 of the special-shaped prism P1 and the imaging chip.

[0104] The following refers to Figure 18and Table 5, the first lens L1 has positive refractive power, the object side surface is convex, and the image side surface is concave. The second lens L2 has negative refractive power, the object side surface is concave, and the image side surface is concave. The third lens L3 has negative refractive power, the object side surface is concave, and the image side surface is concave. The fourth lens L4 has positive refractive power, the object side surface is convex, and the image side surface is concave. The incident surface S1 and the exit surface S5 of the special prism P1 are both planes. The filter IR has an object side surface and an image side surface, and both the object side surface and the image side surface are planes. The light rays can pass through the lens assembly 10 and the special prism P1 in turn, specifically: the light stop STO, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the special prism P1, and the filter IR, and finally form an image on the imaging surface IMG of the imaging chip; wherein the light rays passing through the lens assembly 10 are incident from the incident surface S1 to the special prism P1, are reflected for the first time to the second reflecting surface S3 through the first reflecting surface S2, and are reflected once in turn through the second reflecting surface S3 and the third reflecting surface S4, respectively, and finally pass through the optical path compensation space and are emitted from the exit surface S5 to the imaging surface IMG of the imaging chip.

[0105] Table 5 shows the basic parameter table of the long-focus lens of Example 3, wherein the units of the curvature radius, the interval / thickness, and the focal length are all millimeters (mm).

[0106] Table 5:

[0107] Table 6 shows the conic coefficients and high-order coefficients A2, A4, A6, A8, A10, A12, A14, and A16 when the object side surface and the image side surface of the first lens L1 to the fourth lens L4 in Example 3 are even aspheric surfaces. Wherein the surface type of each even aspheric surface can be defined by the formula (1) given in the above-mentioned Example 1.

[0108] Table 6:

[0109] In embodiment 3, the focal length f of the telephoto lens is 23.49 mm, the aperture FNO is 2.59, the imaging circle diameter is 13.776 mm, and the working waveband is 420~680 nm. The distance M5 between the optical axis of the lens assembly 10 and the center of the imaging chip is 17.51 mm, and the relationship between M5 and the focal length f of the telephoto lens satisfies M5 / f = 0.75, which meets 0.3≤M5 / f≤1.5. The equivalent thickness Hp of the special prism P1 is 22.94 mm, and the relationship between Hp and the focal length f of the telephoto lens satisfies Hp / f = 0.98, which meets 0.34≤Hp / f≤2.3. The thickness M1 of the lens assembly 10 is 5.84 mm, the thickness M2 of the special prism P1 is 5.10 mm, and the relationship between M1 and M2 satisfies M1 / M2 = 1.15, which meets 0.54≤M1 / M2≤2.43. The included angle θ1 between the incidence surface S1 of the special prism P1 and the first reflection surface S2 of the special prism P1 satisfies θ1 = 26°, which meets 22°≤θ1≤34°. The connecting surface S6 is a plane, and the included angle θ2 between the connecting surface S6 and the 0.6 field of view positive field edge light satisfies θ2 = 10°, which meets 2°≤θ2≤35°. The distance M3 between the lens assembly 10 and the special prism P1 satisfies M3 = 0.18 mm, which meets 0.1 mm≤M3. The distance M4 between the special prism P1 and the imaging chip satisfies M4 / FNO = 0.96, which meets 0.2≤M4 / FNO≤2.2. At the intersection between the connecting surface S6 and the second reflection surface S3, the intersection point between the 0.6 field of view negative field edge light and the second reflection surface S3, and the virtual intersection point between the 0.6 field of view positive field edge light and the extension surface of the second reflection surface S3, the distance M6 satisfies M6 = 0.22 mm, which meets 0.22 mm≤M6≤3.89 mm. The distance M7 from the reflection point of the 0 field of view chief ray on the first reflection surface S2 to the reflection point of the 0 field of view chief ray on the third reflection surface S4 to the exit surface S5 satisfies M7 / M2 = 2.06, which meets 1.74≤M7 / M2≤4.1. The distance M8 from the reflection point of the 0.6 field of view chief ray on the third reflection surface S4 to the exit surface S5 to the intersection point of the exit surface S5 and the third reflection surface S4 satisfies M8 = 1.64 mm, which meets 0.2 mm≤M8. The focal length f1 of the first lens L1 and the focal length f of the telephoto lens satisfy f1 / f = 0.41, which meets 0.14≤f1 / f≤2. The relationship between the focal length f1 of the first lens L1 and the focal length f2 of the second lens L2 satisfies |f2| / f1 = 7.06, which meets 2.08≤|f2| / f1.

[0110] Figure 19The MTF curve of the long-focus lens of embodiment 3 is shown, and the MTF (Modulation Transfer Function) curve shows the transmission of the imaging system to the image details (i.e. image contrast) of different spatial frequencies, and the OTF modulus is greater than 0.5 at a spatial frequency of 89 lp / mm, and the resolving power is good. Figure 20 The distortion diagram of the long-focus lens of embodiment 3 is shown, and the distortion is less than 2%, and the correction is good. Figure 21 The relative luminance and Y field diagram of the long-focus lens of embodiment 3 is shown, and the relative luminance is greater than 0.6, and the picture luminance is uniform. According to Figures 19 to 21 It can be seen that the long-focus lens given by embodiment 3 has good resolving power, good correction, and uniform picture luminance, and can achieve good imaging quality.

[0111] Example 4 The following refers to Figure 22 The long-focus lens according to embodiment 4 of the present application is described. Figure 22 The structural schematic diagram of the long-focus lens according to embodiment 4 of the present application is shown.

[0112] As Figure 22 shown, the long-focus lens sequentially includes a lens assembly 10 and a special-shaped prism P1 from the object side to the image side; the special-shaped prism P1 includes an incident surface S1, a first reflecting surface S2, a second reflecting surface S3, a third reflecting surface S4, an exit surface S5, and a connecting surface S6; the incident surface S1 and the second reflecting surface S3 are the same surface, the second reflecting surface S3 is oppositely arranged with the third reflecting surface S4, and the first reflecting surface S2 is oppositely arranged with the exit surface S5; one side of the exit surface S5 intersects the third reflecting surface S4, and the other side of the exit surface S5 is located on the side of the second reflecting surface S3 away from the third reflecting surface S4, the connecting surface S6 intersects the second reflecting surface S3 to form a first intersection line E1, the connecting surface S6 intersects the opposite side of the exit surface S5 to form a second intersection line E2, the third reflecting surface S4 intersects the exit surface S5 to form a third intersection line E3, and the connecting surface S6 is a single continuous surface, for example, a plane, and the connecting surface S6 and the third reflecting surface S4 form an optical path compensation space. The lens assembly 10 includes a first lens L1, a second lens L2, and a third lens L3. A stop STO can be arranged on the object side surface of the first lens L1. A filter IR can be arranged between the exit surface S5 of the special-shaped prism P1 and the imaging chip.

[0113] The following refers to Figure 22and Table 7, the first lens L1 has positive refractive power, the object side surface is convex, and the image side surface is concave. The second lens L2 has positive refractive power, the object side surface is convex, and the image side surface is concave. The third lens L3 has negative refractive power, the object side surface is concave, and the image side surface is convex. The entrance surface S1 of the shaped prism P1 is a plane, and the exit surface S5 of the shaped prism P1 is an aspheric surface. The filter IR has an object side surface and an image side surface, and the object side surface is a plane and the image side surface is a spherical surface. The light rays can pass through the lens assembly 10 and the shaped prism P1 in turn, specifically: the light stop STO, the first lens L1, the second lens L2, the third lens L3, the shaped prism P1 and the filter IR, and finally form an image on the imaging surface IMG of the imaging chip; wherein the light passing through the lens assembly 10 is incident from the entrance surface S1 to the shaped prism P1, is reflected for the first time to the second reflecting surface S3 through the first reflecting surface S2, and is reflected once in turn through the second reflecting surface S3 and the third reflecting surface S4, respectively, and finally passes through the optical path compensation space and is emitted from the exit surface S5 to the imaging surface IMG of the imaging chip.

[0114] In this embodiment 4, the exit surface S5 of the shaped prism P1 is an aspheric surface, so that the shaped prism P1 of this embodiment 4 has one less lens than the shaped prism P1 of embodiment 3, and the total height of the shaped prism P1 is reduced by about 1 mm.

[0115] Table 7 shows the basic parameter table of the long-focus lens of embodiment 4, wherein the units of the radius of curvature, the interval / thickness and the focal length are all millimeters (mm).

[0116] Table 7:

[0117] Table 8 shows the conic coefficients and high-order coefficients A2, A4, A6, A8, A10, A12, A14 and A16 when the object side surface and the image side surface of the first lens L1 to the third lens L3 in embodiment 4 are even aspheric surfaces. Wherein the surface type of each even aspheric surface can be defined by the formula (1) given in the above embodiment 1.

[0118] Table 8:

[0119] In embodiment 4, the focal length f of the telephoto lens is 23.4 mm, the aperture FNO is 2.59, the imaging circle diameter is 13.77 mm, and the working waveband is 420~680 nm. The distance M5 between the optical axis of the lens assembly 10 and the center of the imaging chip is 16.15 mm, and the relationship between M5 and the focal length f of the telephoto lens satisfies M5 / f = 0.69, which meets 0.3≤M5 / f≤1.5. The equivalent thickness Hp of the special prism P1 is 22.36 mm, and the relationship between Hp and the focal length f of the telephoto lens satisfies Hp / f = 0.96, which meets 0.34≤Hp / f≤2.3. The thickness M1 of the lens assembly 10 is 4.56 mm, the thickness M2 of the special prism P1 is 5.2 mm, and the relationship between M1 and M2 satisfies M1 / M2 = 0.88, which meets 0.54≤M1 / M2≤2.43. The included angle θ1 between the incident surface S1 of the special prism P1 and the first reflecting surface S2 of the special prism P1 satisfies θ1 = 26°, which meets 22°≤θ1≤34°. The connecting surface S6 is a plane, and the included angle θ2 between the connecting surface S6 and the 0.6 field of view positive field edge light satisfies θ2 = 28°, which meets 2°≤θ2≤35°. The distance M3 between the lens assembly 10 and the special prism P1 satisfies M3 = 0.3 mm, which meets 0.1 mm≤M3. The distance M4 between the special prism P1 and the imaging chip satisfies M4 / FNO = 0.47, which meets 0.2≤M4 / FNO≤2.2. At the intersection between the connecting surface S6 and the second reflecting surface S3, the intersection point between the 0.6 field of view negative field edge light and the second reflecting surface S3, and the virtual intersection point between the 0.6 field of view positive field edge light and the extension of the second reflecting surface S3, the distance M6 satisfies M6 = 0.56 mm, which meets 0.22 mm≤M6≤3.89 mm. The distance M7 from the reflection point of the 0 field of view chief ray on the first reflecting surface S2 to the reflection point of the 0 field of view chief ray on the third reflecting surface S4 to the exit surface S5 satisfies M7 / M2 = 2.02, which meets 1.74≤M7 / M2≤4.1. The distance M8 from the reflection point of the 0.6 field of view chief ray on the third reflecting surface S4 to the exit surface S5 to the intersection point of the exit surface S5 and the third reflecting surface S4 satisfies M8 = 0.6 mm, which meets 0.2 mm≤M8. The focal length f1 of the first lens L1 and the focal length f of the telephoto lens satisfy f1 / f = 0.48, which meets 0.14≤f1 / f≤2. The relationship between the focal length f1 of the first lens L1 and the focal length f2 of the second lens L2 satisfies |f2| / f1 = 17.72, which meets 2.08≤|f2| / f1.

[0120] Figure 23The MTF curve of the long-focus lens of embodiment 4 is shown, and the MTF (Modulation Transfer Function) curve shows the transmission of the imaging system to the image details (i.e. image contrast) of different spatial frequencies. The OTF modulus is greater than 0.5 at a spatial frequency of 89 lp / mm, and the resolving power is good. Figure 24 The distortion diagram of the long-focus lens of embodiment 4 is shown, and the distortion is less than 2%, and the correction is good. Figure 25 The relative illumination and Y field diagram of the long-focus lens of embodiment 4 is shown, and the relative illumination is greater than 0.6, and the picture illumination is uniform. According to Figures 23 to 25 It can be seen that the long-focus lens given by embodiment 4 has good resolving power, good correction, and uniform picture illumination, and can achieve good imaging quality.

[0121] Example 5 The following refers to Figure 26 The long-focus lens according to embodiment 5 of the present application is described. Figure 26 The structural schematic diagram of the long-focus lens according to embodiment 5 of the present application is shown.

[0122] As Figure 26 shown, the long-focus lens sequentially includes a lens assembly 10 and a special prism P1 from the object side to the image side; the special prism P1 includes an incident surface S1, a first reflecting surface S2, a second reflecting surface S3, a third reflecting surface S4, an exit surface S5, and a connecting surface S6; the incident surface S1 and the second reflecting surface S3 are the same surface, the second reflecting surface S3 is oppositely arranged with the third reflecting surface S4, and the first reflecting surface S2 is oppositely arranged with the exit surface S5; one side of the exit surface S5 intersects the third reflecting surface S4, the other side of the exit surface S5 is located on the side of the second reflecting surface S3 away from the third reflecting surface S4, the connecting surface S6 intersects the second reflecting surface S3 to form a first intersection line E1, the connecting surface S6 intersects the opposite side of the exit surface S5 to form a second intersection line E2, the third reflecting surface S4 intersects the exit surface S5 to form a third intersection line E3, and the connecting surface S6 is a composite surface composed of a first sub-surface S61 and a second sub-surface S62, the first sub-surface S61 intersects the second reflecting surface S3 to form the first intersection line E1, and the second sub-surface S62 intersects the opposite side of the exit surface S5 to form the second intersection line E2; the first sub-surface S61 and the second sub-surface S62 can both be planes, the second sub-surface S62 can be oppositely parallel to the second reflecting surface S3, and the connecting surface S6 and the third reflecting surface S4 form an optical path compensation space. The lens assembly 10 includes a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4. A stop STO can be arranged on the object side surface of the first lens L1. A filter IR can be arranged between the exit surface S5 of the special prism P1 and an imaging chip.

[0123] The following refers toFigure 26 and Table 9, the first lens L1 has positive refractive power, the object side surface is convex, and the image side surface is concave. The second lens L2 has positive refractive power, the object side surface is concave, and the image side surface is convex. The third lens L3 has negative refractive power, the object side surface is concave, and the image side surface is concave. The fourth lens L4 has positive refractive power, the object side surface is convex, and the image side surface is convex. The entrance surface S1 of the shaped prism P1 is a plane, and the exit surface S5 of the shaped prism P1 is an aspheric surface. The filter IR has an object side surface and an image side surface, and the object side surface is a plane, and the image side surface is a plane. The light rays can pass through the lens assembly 10 and the shaped prism P1 in turn, specifically: the light stop STO, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the shaped prism P1 and the filter IR, and finally form an image on the imaging surface IMG of the imaging chip; wherein the light rays passing through the lens assembly 10 are incident from the entrance surface S1 to the shaped prism P1, and the first reflection surface S2 is reflected to the second reflection surface S3 for the first time, and then the second reflection surface S3 and the third reflection surface S4 are reflected once in turn, and finally pass through the optical path compensation space and exit from the exit surface S5 to the imaging surface IMG of the imaging chip.

[0124] Table 9 shows the basic parameter table of the long-focus lens of Example 5, wherein the units of the radius of curvature, the interval / thickness and the focal length are all millimeters (mm).

[0125] Table 9:

[0126] Table 10 shows the conic coefficients and high-order coefficients A2, A4, A6, A8, A10, A12, A14 and A16 when the object side surface and the image side surface of the first lens L1 to the fourth lens L4 in Example 5 are even aspheric surfaces. Wherein the surface type of each even aspheric surface can be defined by the formula (1) given in the above-mentioned Example 1.

[0127] Table 10:

[0128] In Example 5, the telephoto lens has a focal length f of 80mm, an aperture of FnO2, an imaging circle diameter of 8.56mm, and an operating wavelength of 420~680nm. The distance M5 between the optical axis of the lens assembly 10 and the center of the imaging chip is 24mm, and its relationship with the focal length f of the telephoto lens is M5 / f = 0.3, satisfying: 0.3≤M5 / f≤1.5. The equivalent thickness Hp of the irregular prism P1 is 27.53mm, and its relationship with the focal length f of the telephoto lens is Hp / f = 0.34, satisfying: 0.34≤Hp / f≤2.3. The thickness M1 of the lens assembly 10 is 8.5mm, and the thickness M2 of the irregular prism P1 is 3.5mm, and their relationship is M1 / M2 = 2.43, satisfying: 0.54≤M1 / M2≤2.43. The angle θ1 between the incident surface S1 and the first reflecting surface S2 of the irregular prism P1 is θ1=34°, satisfying: 22°≤θ1≤34°. The connecting surface S6 is a composite surface composed of a first sub-surface S61 and a second sub-surface S61. The angle θ2 between the first sub-surface S61 and the edge ray of the 0.6 field of view is θ2=35°, satisfying: 2°≤θ2≤35°. The distance M3 between the lens assembly 10 and the irregular prism P1 is M3=0.28mm, satisfying: 0.1mm≤M3. The distance M4 between the irregular prism P1 and the imaging chip is 4.4mm, and its relationship with the aperture FNO of the telephoto lens is M4 / FNO=2.2, satisfying: 0.2≤M4 / FNO≤2.2. At the intersection of the adjacent connecting surface S6 and the second reflecting surface S3, the distance M6 between the intersection point of the negative field-of-view ray at the edge of the 0.6 field of view and the second reflecting surface S3, and the virtual intersection point between the positive field-of-view ray at the edge of the 0.6 field of view and the extended surface of the second reflecting surface S3, is M6 = 3.89 mm, satisfying: 0.22 mm ≤ M6 ≤ 3.89 mm. The distance M7 between the reflection point of the 0 field-of-view principal ray at the first reflecting surface S2 and the reflection point at the third reflecting surface S4 towards the exiting surface S5 is 10.5 mm. The relationship between this distance and the thickness M2 of the irregular prism P1 is M7 / M2 = 4.1, satisfying: 1.74 ≤ M7 / M2 ≤ 4.1. The distance M8 between the reflection point of the 0.6 field-of-view principal ray at the third reflecting surface S4 towards the exiting surface S5, and the intersection point of the exiting surface S5 and the third reflecting surface S4, is M8 = 4.75 mm, satisfying: 0.2 mm ≤ M8. The focal length f1 of the first lens L1 is equal to the focal length f of the telephoto lens, f1 / f = 0.14, satisfying: 0.14 ≤ f1 / f ≤ 2. The focal length f1 of the first lens L1 is equal to the focal length f2 of the second lens L2, |f2| / f1 = 11.56, satisfying: 2.08 ≤ |f2| / f1.

[0129] Figure 27The MTF curve of the long-focus lens of embodiment 5 is shown, and the MTF (Modulation Transfer Function) curve shows the transmission of the imaging system to the image details (i.e. image contrast) of different spatial frequencies. The OTF modulus is greater than 0.5 at a spatial frequency of 89 lp / mm, and the resolving power is good. Figure 28 The distortion diagram of the long-focus lens of embodiment 5 is shown, and the distortion is less than 2%, and the correction is good. Figure 29 The relative luminance and Y field diagram of the long-focus lens of embodiment 5 is shown, and the relative luminance is greater than 0.6, and the picture luminance is uniform. According to Figures 27 to 29 It can be seen that the long-focus lens given by embodiment 5 has good resolving power, good correction, and uniform picture luminance, and can achieve good imaging quality.

[0130] Example 6 The following refers to Figure 30 The long-focus lens according to embodiment 6 of the present application is described. Figure 30 The structural schematic diagram of the long-focus lens according to embodiment 5 of the present application is shown.

[0131] As Figure 30 shown, the long-focus lens sequentially includes a lens assembly 10 and a special prism P1 from the object side to the image side; the special prism P1 includes an incident surface S1, a first reflecting surface S2, a second reflecting surface S3, a third reflecting surface S4, an exit surface S5, and a connecting surface S6; the incident surface S1 and the second reflecting surface S3 are the same surface, the second reflecting surface S3 is oppositely arranged with the third reflecting surface S4, and the first reflecting surface S2 is oppositely arranged with the exit surface S5; one side of the exit surface S5 intersects the third reflecting surface S4, the other side of the exit surface S5 is located on the side of the second reflecting surface S3 away from the third reflecting surface S4, the connecting surface S6 intersects the second reflecting surface S3 to form a first intersection line E1, the connecting surface S6 intersects the opposite side of the exit surface S5 to form a second intersection line E2, the third reflecting surface S4 intersects the exit surface S5 to form a third intersection line E3, and the connecting surface S6 is a composite surface composed of a first sub-surface S61 and a second sub-surface S62, the first sub-surface S61 intersects the second reflecting surface S3 to form the first intersection line E1, and the second sub-surface S62 intersects the opposite side of the exit surface S5 to form the second intersection line E2; the first sub-surface S61 and the second sub-surface S62 can both be planes, the second sub-surface S62 can be oppositely parallel to the second reflecting surface S3, and the connecting surface S6 and the third reflecting surface S4 form an optical path compensation space. The lens assembly 10 includes a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4. A stop STO can be arranged on the object side surface of the first lens L1. A filter IR can be arranged between the exit surface S5 of the special prism P1 and an imaging chip.

[0132] The following refers toFigure 30 According to Table 11, the first lens L1 has positive optical power, with a concave object-side surface and a convex image-side surface. The second lens L2 has negative optical power, with a concave object-side surface and a convex image-side surface. The third lens L3 has negative optical power, with a concave object-side surface and a concave image-side surface. The fourth lens L4 has positive optical power, with a convex object-side surface and a concave image-side surface. The incident surface S1 of the irregular prism P1 is a plane, and the exit surface S5 of the irregular prism P1 is an aspherical surface. The filter IR has an object-side surface and an image-side surface, with both the object-side and image-side surfaces being planes. Light rays can pass sequentially through the lens assembly 10 and the irregular prism P1, specifically: aperture STO, first lens L1, second lens L2, third lens L3, fourth lens L4, irregular prism P1 and filter IR, and finally image onto the imaging surface IMG of the imaging chip; wherein, the light rays passing through the lens assembly 10 enter the irregular prism P1 from the incident surface S1, undergo a first reflection on the first reflecting surface S2 to the second reflecting surface S3, and then undergo a second reflection on the second reflecting surface S3 and the third reflecting surface S4 respectively, and finally pass through the optical path compensation space and exit from the exit surface S5 to the imaging surface IMG of the imaging chip.

[0133] Table 11 shows the basic parameters of the telephoto lens of Example 6, where the units for radius of curvature, spacing / thickness, and focal length are all millimeters (mm).

[0134] Table 11:

[0135] Table 12 shows the conic coefficients and higher-order coefficients A2, A4, A6, A8, A10, A12, A14, and A16 that can be used when the object-side and image-side surfaces of the first lens L1 to the fourth lens L4 in Embodiment 6 are even-order aspherical surfaces. The surface shape of each even-order aspherical surface can be defined by formula (1) given in Embodiment 1 above.

[0136] Table 12:

[0137] In the embodiment 6, the focal length f of the long-focus lens is 10 mm, the aperture FNO is 5, the imaging circle diameter is 8.6 mm, and the working waveband is 420~680 nm. The distance M5 between the optical axis of the lens assembly 10 and the center of the imaging chip is 15 mm, and the relationship between the distance M5 and the focal length f of the long-focus lens satisfies M5 / f =1.5, which meets 0.3≤M5 / f≤1.5. The equivalent thickness Hp of the special-shaped prism P1 is 23.00 mm, and the relationship between the equivalent thickness Hp and the focal length f of the long-focus lens satisfies Hp / f =2.3, which meets 0.34≤Hp / f≤2.3. The thickness M1 of the lens assembly 10 is 2.7 mm, the thickness M2 of the special-shaped prism P1 is 5 mm, and the relationship between the thickness M1 and the thickness M2 satisfies M1 / M2=0.54, which meets 0.54≤M1 / M2≤2.43. The included angle θ1 between the incident surface S1 of the special-shaped prism P1 and the first reflecting surface S2 of the special-shaped prism P1 satisfies θ1=22°, which meets 22°≤θ1≤34°. The connecting surface S6 is a composite surface composed of a first sub-surface S61 and a second sub-surface S61, and the included angle θ2 between the first sub-surface S61 in the connecting surface S6 and the 0.6 field of view positive field edge light satisfies θ2=2°, which meets 2°≤θ2≤35°. The distance M3 between the lens assembly 10 and the special-shaped prism P1 satisfies M3=0.1 mm, which meets 0.1 mm≤M3. The distance M4 between the special-shaped prism P1 and the imaging chip is 1 mm, and the relationship between the distance M4 and the aperture FNO of the long-focus lens satisfies M4 / FNO=0.2, which meets 0.2≤M4 / FNO≤2.2. At the intersection between the connecting surface S6 and the second reflecting surface S3, the intersection point between the 0.6 field of view negative field edge light and the second reflecting surface S3, and the virtual intersection point between the 0.6 field of view positive field edge light and the extension surface of the second reflecting surface S3, the distance M6 satisfies M6=2.55 mm, which meets 0.22 mm≤M6≤3.89 mm. The distance M7 between the reflection point of the 0 field of view chief ray on the first reflecting surface S2 and the reflection point of the 0 field of view chief ray on the third reflecting surface S4 to the exit surface S5 satisfies M7 / M2=1.74, which meets 1.74≤M7 / M2≤4.1. The distance M8 between the reflection point of the 0.6 field of view chief ray on the third reflecting surface S4 to the exit surface S5 and the intersection point between the exit surface S5 and the third reflecting surface S4 satisfies M8=0.2 mm, which meets 0.2 mm≤M8. The relationship between the focal length f1 of the first lens L1 and the focal length f of the long-focus lens satisfies f1 / f =2, which meets 0.14≤f1 / f≤2. The relationship between the focal length f1 of the first lens L1 and the focal length f2 of the second lens L2 satisfies |f2| / f1=2.08, which meets 2.08≤|f2| / f1.

[0138] Figures 31 to 33The MTF curve of the long-focus lens of embodiment 6 is shown, the MTF (Modulation Transfer Function) curve shows the transfer of image details (i.e. image contrast) of an imaging system to different spatial frequencies, and the OTF modulus is greater than 0.3 at a spatial frequency of 89 lp / mm, and the resolving power is good. ​ The distortion graph of the long-focus lens of embodiment 6 is shown, and the distortion is less than 2%, and the correction is good. ​ The relative illumination and Y field of view graph of the long-focus lens of embodiment 6 is shown, and the relative illumination is greater than 0.4, and the picture illumination is uniform. ​ It can be seen that the long-focus lens given by embodiment 6 has good resolving power, good correction, and uniform picture illumination, and can achieve good imaging quality.

[0139] In summary, embodiment 1, embodiment 2, embodiment 3, embodiment 4, embodiment 5 and embodiment 6 respectively meet the relationship shown in Table 13.

[0140] Table 13:

[0141] The above description is only the preferred embodiment of the present application and the explanation of the technical principles applied. It should be understood by those skilled in the art that the scope of the application involved in the present application is not limited to the technical solutions formed by the specific combination of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the technical solutions formed by mutually replacing the above features and the technical features disclosed in the present application (but not limited to) having similar functions.

Claims

1. A telephoto lens, characterized in that, The image-side components, from the object side to the image side, sequentially include a lens assembly and an irregularly shaped prism. The irregularly shaped prism includes an incident surface, a first reflecting surface, a second reflecting surface, a third reflecting surface, an exit surface, and a connecting surface. The incident surface and the second reflecting surface are the same surface; the second reflecting surface and the third reflecting surface are positioned opposite each other; the first reflecting surface and the exit surface are positioned opposite each other. One side of the exit surface intersects with the third reflecting surface, and the opposite side of the exit surface is located on the side of the second reflecting surface furthest from the third reflecting surface. The connecting surface intersects with the second reflecting surface to form a first intersection line. The connecting surface intersects with the opposite side of the emitting surface to form a second intersection line, and the third reflecting surface intersects with the emitting surface to form a third intersection line. The connecting surface is a single continuous surface or a composite surface composed of a first sub-surface and a second sub-surface. The first sub-surface intersects with the second reflecting surface to form the first intersection line, and the second sub-surface intersects with the opposite side of the emitting surface to form a second intersection line. An optical path compensation space is formed between the connecting surface and the third reflecting surface. The irregular prism is an integrally formed structure or is composed of at least two sub-prisms bonded together. Light passing through the lens assembly enters the irregular prism from the incident surface, undergoes a first reflection from the first reflecting surface to the second reflecting surface, and is then reflected at least once each by the second and third reflecting surfaces, finally passing through the optical path compensation space and exiting from the exit surface to the imaging surface of the imaging chip.

2. The telephoto lens according to claim 1, characterized in that, The distance M5 between the optical axis of the lens assembly and the center of the imaging chip satisfies the following condition with respect to the focal length f of the telephoto lens: 0.3 ≤ M5 / f ≤ 1.

5.

3. The telephoto lens according to claim 1, characterized in that, The equivalent thickness Hp of the irregular prism and the focal length f of the telephoto lens satisfy the following condition: 0.34 ≤ Hp / f ≤ 2.

3.

4. The telephoto lens according to claim 1, characterized in that, The thickness M1 of the lens assembly and the thickness M2 of the irregular prism satisfy the following condition: 0.54 ≤ M1 / M2 ≤ 2.

43.

5. The telephoto lens according to claim 1, characterized in that, The connecting surface is a plane, and the angle θ2 between the connecting surface and the edge light rays of the 0.6 field of view front field of view satisfies: 2°≤θ2≤35°.

6. The telephoto lens according to claim 1, characterized in that, At the intersection of the connecting surface and the second reflecting surface, the distance M6 between the intersection point of the negative field-of-view ray at the edge of the 0.6 field of view and the second reflecting surface and the virtual intersection point of the positive field-of-view ray at the edge of the 0.6 field of view and the extended surface of the second reflecting surface satisfies: 0.22mm≤M6≤3.89mm.

7. The telephoto lens according to claim 1, characterized in that, The distance M7 between the reflection point of the 0 field principal ray on the first reflecting surface and the reflection point on the third reflecting surface towards the exiting surface, and the thickness M2 of the irregular prism, satisfy the following condition: 1.74≤M7 / M2≤4.

1.

8. The telephoto lens according to claim 1, characterized in that, The distance M8 from the point where the principal ray of the 0.6 field of view is reflected from the third reflecting surface to the exiting surface to the intersection of the exiting surface and the third reflecting surface satisfies: 0.2mm≤M8.

9. The telephoto lens according to claim 1, characterized in that, The irregular prism includes a first sub-prism and a second sub-prism glued together. The first sub-prism includes a second reflecting surface and a third reflecting surface. The second sub-prism includes a connecting surface and an exiting surface. The first sub-prism and the second sub-prism are connected by a first glued surface. One side of the first glued surface coincides with the first intersection line, and the other side of the first glued surface coincides with the third intersection line. Alternatively, the irregular prism includes a third sub-prism and a fourth sub-prism glued together. The third sub-prism includes the second reflecting surface, the third reflecting surface, and a first portion of the exiting surface. The fourth sub-prism includes the connecting surface and a second portion of the exiting surface. The first and second portions of the exiting surface intersect to form a fourth intersection line, and the fourth intersection line is located at the intersection of the extended surface of the second reflecting surface and the exiting surface. The third sub-prism and the fourth sub-prism are connected by a second glued surface. One side of the second glued surface coincides with the first intersection line, and the other side of the second glued surface coincides with the fourth intersection line.

10. The telephoto lens according to claim 1, characterized in that, The first reflecting surface of the irregular prism is tinted.

Images