Telephoto lens for external attachment to mobile phones

Abstract

Telephoto lens for external attachment to mobile phones, characterized in that the physical mechanical length of the telephoto lens is less than 12 mm per magnification factor in relation to the zoom magnification; where the physical mechanical length of the telephoto lens is defined as the distance from the front cover of the telephoto lens to the front of the mobile phone lens when the telephoto lens is attached to the mobile phone; where the specified zoom magnification is defined as B / A per magnification factor, where A is the original focal length of the mobile phone lens and B is the total focal length after attaching the external telephoto lens to the mobile phone.

Description

Technical area

[0001] The present invention relates to the technical field of optical lenses and in particular a telephoto lens for external attachment to mobile phones. Background technology

[0002] To improve the ability to capture distant details with mobile phones, various manufacturers are increasing the telephoto lens performance of their devices. However, due to the limited dimensions of mobile phones, the performance of native telephoto lenses on smartphones is restricted. When photographing distant objects with a mobile phone's native telephoto lens, using the device's digital zoom function leads to a significant deterioration in image sharpness. Therefore, attaching an external telephoto lens to the mobile phone is necessary to meet the demands of capturing high-resolution images from a great distance.

[0003] External telephoto lenses, due to their longer focal length, typically have a higher number of lenses and a greater overall optical system length than conventional lenses. This often results in external telephoto lenses for mobile phones being longer and heavier than average. When taking photos with a mobile phone in combination with an external telephoto lens, camera shake is common. Therefore, to achieve stable image quality, a tripod is necessary to stabilize the external telephoto lens. Content of the utility model

[0004] Therefore, the technical problem to be solved by the present utility model is to overcome the difficulties encountered in the existing technology, in particular the large volume and weight of external telephoto lenses for mobile phones and the resulting image blurring in handheld shots, in order to provide a portable telephoto lens for external attachment to mobile phones.

[0005] The technical solution to the aforementioned technical problems is as follows: Telephoto lens for external attachment to mobile phones, wherein the physical mechanical length of the telephoto lens is less than 12 mm per magnification factor in relation to the zoom magnification; where the physical mechanical length of the telephoto lens is defined as the distance from the front cover of the telephoto lens to the front of the mobile phone lens when the telephoto lens is attached to the mobile phone; where the specified zoom magnification is defined as B / A per magnification factor, where A is the original focal length of the mobile phone lens and B is the total focal length after attaching the external telephoto lens to the mobile phone.

[0006] Furthermore, the telephoto lens comprises, along the optical path from the object side to the image side, a first lens group G1, a second lens group, a prism group, a third lens group and a fourth lens group arranged successively; wherein the focal lengths of all lens groups satisfy the following conditions: 1.5 <f(G1) / f(G2)<3; 1.2 <f(G3) / f(G4)<2,4; 0.1 <f(G3−G4) / f(G1−G4)<0,5; where f(G1) denotes the focal length of the first lens group, f(G2) the focal length of the second lens group, f(G3) the focal length of the third lens group, f(G4) the focal length of the fourth lens group, f(G3-G4) the combined focal length from the third lens group to the fourth lens group, and f(G1-G4) the combined focal length from the first lens group to the fourth lens group.

[0007] Furthermore, all lenses in the first lens group, the second lens group, the third lens group and the fourth lens group are spherical lenses.

[0008] Furthermore, the first lens group comprises a first lens and a second lens arranged along the optical axis from the object side to the image side in this order; wherein the first lens is a spherical lens with a positive focal length and the second lens is a spherical lens with a negative focal length.

[0009] Furthermore, the second lens group comprises a third lens and a fourth lens, arranged along the optical axis from the object side to the image side in this order; wherein the third lens is a spherical lens with a positive focal length and the fourth lens is a spherical lens with a negative focal length.

[0010] Furthermore, the third lens group includes a fifth lens, the fifth lens being a spherical lens with a positive focal length.

[0011] Furthermore, the fourth lens group is arranged along the optical axis from the object side to the image side in the following order: sixth lens, seventh lens, eighth lens and ninth lens; wherein the sixth lens is a spherical lens with a positive focal length, the seventh lens is a spherical lens with a negative focal length, the eighth lens is a spherical lens with a positive focal length and the ninth lens is a spherical lens with a negative focal length.

[0012] Furthermore, the prism group includes at least one prism.

[0013] Furthermore, all lenses in the first lens group, the second lens group, the third lens group and the fourth lens group are optical glasses.

[0014] The present technical concept of the utility models offers the following advantages: Since the physical mechanical length of the telephoto lens is less than 12 mm per magnification factor, the length and weight of the telephoto lens can be reduced for the same zoom magnification. When the telephoto lens is attached externally to a mobile phone, no additional tripod support is required to ensure stable image capture. Furthermore, the design demonstrates a significant increase in image sharpness; when shooting at a defined distance, the sharpness perceived by the user is increased by at least a factor of two compared to shooting without an external lens on the mobile phone. Figures

[0015] To more clearly illustrate the specific embodiments of the present utility model or the technical solutions in the prior art, the drawings that must be used in the specific embodiments or the description of the prior art are briefly presented below. Naturally, the drawings in the following description represent some embodiments of the present utility model. Other drawings can be obtained by the person skilled in the art based on these drawings without any creative effort. Fig. Figure 1 shows the equivalent beam path diagram of the telephoto lens for external mounting on mobile phones according to the first embodiment of the present utility model; Fig. 2.1 shows the diagram of the spherical aberration of the telephoto lens for external attachment to mobile phones according to the first embodiment of the present utility model; Fig.2.2 shows the field curvature diagram of the telephoto lens for external attachment to mobile phones according to the first embodiment of the present utility model; Fig. 2.3 shows the distortion diagram of the telephoto lens for external attachment to mobile phones according to the first embodiment of the present utility model; Fig. Figure 3 shows the equivalent beam path diagram of the telephoto lens for external attachment to mobile phones according to the second embodiment of the present utility model; Fig. 4.1 shows the diagram of the spherical aberration of the telephoto lens for external attachment to mobile phones according to the second embodiment of the present utility model; Fig. 4.2 shows the field curvature diagram of the telephoto lens for external attachment to mobile phones according to the second embodiment of the present utility model; Fig.4.3 shows the distortion diagram of the telephoto lens for external attachment to mobile phones according to the second embodiment of the present utility model.

[0016] Labels in the accompanying drawings: G1, first lens group; G2, second lens group; G3, third lens group; G4, fourth lens group; 1, first lens; 2, second lens; 3, third lens; 4, fourth lens; 5, fifth lens; 6, sixth lens; 7, seventh lens; 8, eighth lens; 9, ninth lens; L, prism group; L1, first prism; L2, second prism; P, mobile phone model. Specific embodiments

[0017] The technical solutions of this utility model are clearly and completely described below in conjunction with the accompanying drawings. The described embodiments are, of course, part of the embodiments of this utility model and not all possible embodiments. Starting from the embodiments of this utility model, all other embodiments that a person skilled in the art could achieve without inventive work fall within the scope of protection of this utility model.

[0018] When describing the utility model, it should be noted that the terms "center," "top," "bottom," "left," "right," "vertical," "horizontal," "inside," "outside," etc., refer to orientations or positions shown in the accompanying drawings or to the orientations or positions in which the subject matter of the application is typically arranged in use. These terms serve only to facilitate and simplify the description of the application and are not intended to indicate or imply that the arrangement or component referred to has a specific orientation or must be constructed and operated in a particular manner. Therefore, they are not to be understood as limiting the utility model. The terms "first," "second," and "third" are used for descriptive purposes only and are not to be interpreted as indicating or implying any relative meaning.

[0019] A telephoto lens for external attachment to mobile phones, such as in Fig.The telephoto lens is primarily designed to be attached to the mobile phone's camera. In combination with the phone's native lens, it allows for the capture of distant objects and their magnification within the image. The physical mechanical length of the telephoto lens is less than 12 mm per magnification factor; for example, the physical mechanical length of the telephoto lens is 10 mm per magnification factor.The physical mechanical length of the telephoto lens is defined as the distance from the front cover of the telephoto lens to the front of the mobile phone lens when the telephoto lens is attached to the mobile phone; the zoom magnification is defined as B / A per magnification factor: if the original focal length of the mobile phone lens is A and, after attaching the telephoto lens, the combined focal length of the telephoto lens and the mobile phone lens as a complete system is B, then the zoom magnification of the telephoto lens intended for external attachment to the mobile phone is B / A per magnification factor.

[0020] As in Fig. 1 The telephoto lens comprises the following lens groups arranged successively along the optical axis from the object side to the image side: first lens group G1, second lens group G2, prism group L, third lens group G3 and fourth lens group G4; wherein the focal lengths of all lens groups satisfy the following conditions: 1.5 <f(G1) / f(G2)<3; 1.2 <f(G3) / f(G4)<2,4; 0.1 <f(G1−G4) / f(G1−G4)<0,5; where f(G1) denotes the focal length of the first lens group (G1), f(G2) the focal length of the second lens group (G2), f(G3) the focal length of the third lens group (G3), f(G4) the focal length of the fourth lens group (G4), f(G3-G4) the combined focal length from the third lens group (G3) to the fourth lens group (G4) and f(G1-G4) the combined focal length from the first lens group (G1) to the fourth lens group (G4).

[0021] In some embodiments of this exemplary embodiment, the first lens group G1 comprises a first lens 1 and a second lens 2, arranged along the optical axis from the object side to the image side in this order; wherein the second lens group G2 comprises a third lens 3 and a fourth lens 4, arranged along the optical axis from the object side to the image side in this order; wherein the prism group L comprises the first prism L1 and the second prism L2, wherein the third lens group G3 comprises the fifth lens 5, and wherein the fourth lens group G4 comprises, successively along the optical axis from the object side to the image side, the sixth lens 6, the seventh lens 7, the eighth lens 8, and the ninth lens 9.The first lens 1 is a spherical lens with a positive focal length; the second lens 2 is a spherical lens with a negative focal length; the third lens 3 is a spherical lens with a positive focal length; the fourth lens 4 is a spherical lens with a negative focal length; the fifth lens 5 is a spherical lens with a positive focal length; the sixth lens 6 is a spherical lens with a positive focal length; the seventh lens 7 is a spherical lens with a negative focal length; the eighth lens 8 is a spherical lens with a positive focal length; and the ninth lens 9 is a spherical lens with a negative focal length. All of these lenses—the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7, the eighth lens 8, and the ninth lens 9—are optical glasses.The penultimate plane of the beam path corresponds to the native lens of the mobile phone model P; the combination of both serves to evaluate the performance after the attachment of an external telephoto lens.

[0022] In some embodiments of the present exemplary embodiment, the number of lenses in the telephoto lens is not limited to 9 lenses. The number of lenses in the telephoto lens can be varied further, as long as the combined focal length of the different lens groups in the telephoto lens satisfies the mathematical relationship mentioned above.

[0023] In some embodiments of this exemplary design, the adjacent surfaces of the first lens 1 and the second lens 2 are bonded together, as are the adjacent surfaces of the seventh lens 7 and the eighth lens 8. The combination of bonded lenses enables effective correction of chromatic aberrations, thereby making the color reproduction of the captured image more realistic. It should be noted that the aforementioned multiple combinations of double-sided bonded spherical lenses are joined by bonding. As an interchangeable embodiment based on the concept of the present utility model, and to distinguish it from this application, modifications of the aforementioned joining methods, such as fitting, one-piece forming, and similar joining methods, as well as adaptive changes to the shape of the joined lens, also fall within the scope of protection of this application.For a single lens or two successive lenses with the same optical signature, a single lens can be divided into two or more lenses, or two successive lenses with the same focal length can be combined into one lens. Such simple modifications to the optical structure of the patent application, e.g., the focal length distribution of the modified lens or lens group, are within the mathematical scope of the patent application. Based on this embodiment, changes and substitutions of the number and combination of lenses made to distinguish the patent application from the present application, provided they do not depart from the fundamental concept of the application, are also within the scope of protection of this application.

[0024] See Fig. 2.1, Fig. 2.2 and Fig. 2.3. Fig.2.1 shows the diagram of the spherical aberration of the telephoto lens according to the first embodiment of the present embodiment. Fig. 2.2 shows the field curvature diagram of the telephoto lens according to the first embodiment of the present embodiment. Fig. Figure 2.3 shows the distortion diagram of the telephoto lens according to the first embodiment of the present embodiment. The curves show that the spherical aberration is substantially less than ±0.1, which ensures sharpness in the center of the image; the field curvature is substantially less than ±0.1, which ensures consistent sharpness across the wide field of view; and the distortion is less than 3%, which guarantees low shape distortion in the image.

[0025] Table 1 shows the actual parameters of the individual lenses of the first embodiment of the telephoto lens, which correspond to the mathematical relationships mentioned above: Table 1: surface Surface shape Radius of curvature (mm) Center thickness (mm) Refractive index Abbe number first lens spherical 226,559 2,03 1,65 64,94 second lens spherical -22,156 0,9 1,89 38,02 spherical -64,993 0,2 third lens spherical 21,657 2,58 1,57 75,66 spherical -125,907 2,23 fourth lens spherical -101,867 1,07 1,65 53,67 spherical 39,956 3,02 first prism spherical infinity 22.89 (optical expansion) 1,59 66,15 spherical infinity 0,5 second prism spherical infinity 33,16 1,53 65,14 spherical infinity 0,2 fifth lens spherical 7,043 5,49 2 27,68 spherical 6,374 2,46 sixth lens spherical -6,706 1,79 1,92 42,32 spherical -4,682 0,88 seventh lens spherical -3,281 2,74 1,72 26,1 eighth lens spherical -8,214 1,99 1,82 51 spherical -5,915 1,79 ninth lens spherical 9,078 1,52 1,99 32,14 spherical 38,495 6,97 Mobile phone model Ideal image plane infinity 15 spherical infinity 0

[0026] In the first embodiment of the present exemplary embodiment, the focal length distribution from the first lens 1 to the ninth lens 9 satisfies the following relationship: f(1−2) / f(3−4)=1.9755; f(5) / f(6−9)=1.784; f(5−9) / f(1−9)=0.2032; where f(mn) denotes the combined focal length of the system from lens m to lens n, where m and n are positive integers and 1 ≤ m < n ≤ 9.

[0027] Table 2 shows the actual parameters of the individual lenses of the second embodiment of the telephoto lens, which correspond to the mathematical relationships mentioned above: Table 2: surface Surface shape Radius of curvature (mm) Center thickness (mm) Refractive index Abbe number first lens spherical 97,642 2,42 1,56 69,14 second lens spherical -18,968 0,9 1,82 42,88 spherical -68,658 0,2 third lens spherical 26,679 3,97 1,54 73,12 spherical -45,847 1,81 fourth lens spherical -76,496 1,47 1,76 53,76 spherical 61,473 2,15 first prism spherical infinity 33,16 1,49 65,99 spherical infinity 0,5 second prism spherical infinity 22,88 1,55 64,95 spherical infinity 0,46 fifth lens spherical 6,294 4,98 2,01 27,16 spherical 5,536 2,37 sixth lens spherical -5,547 1,2 1,82 40,82 spherical -3,903 0,69 seventh lens spherical -3,283 3,13 1,74 27,68 eighth lens spherical -97,789 3,32 1,83 45,46 spherical -7,483 0,29 ninth lens spherical 13,033 1,65 1,93 36,1 spherical -45,372 7,8 Mobile phone model Ideal image plane infinity 15 spherical infinity 0

[0028] Fig. 3, in the second embodiment of the present embodiment, the focal length distribution from the first lens 1 to the ninth lens 9 satisfies the following relationship: f(1−2) / f(3−4)=2.6885; f(5) / f(6−9)=1.6386; f(5−9) / f(1−9)=0,2009; where f(mn) denotes the combined focal length of the system from lens m to lens n, where m and n are positive integers and 1 ≤ m < n ≤ 9.

[0029] See Fig. 4.1, Fig. 4.2, Fig. 4.3, Fig. Figure 4.1 shows the diagram of the spherical aberration of the telephoto lens according to the second embodiment of the present embodiment. Fig. Figure 4.2 shows the field curvature diagram of the telephoto lens according to the second embodiment of the present embodiment. Fig.Figure 4.3 shows the distortion diagram of the telephoto lens according to the second embodiment of the present embodiment. The curves show that the spherical aberration is substantially less than ±0.1, which ensures sharpness in the center of the image; the field curvature is substantially less than ±0.1, which ensures consistent sharpness across the wide field of view; and the distortion is less than 3%, which guarantees low shape distortion in the image.

[0030] The focal length relationship between the first and second embodiments of the telephoto lens is shown in Table 3: Design I Design II f(1-2) / f(3-4) 1,9755 2,6885 f(5) / f(6-9) 1,784 1,6386 f(5-9) / f(1-4) 0,2032 0,2009 Physical mechanical length in relation to zoom magnification (mm per magnification factor) 10 10

[0031] The physical mechanical length of the telephoto lens corresponds to its axial length. In the optical design of the telephoto lens, the total length is determined by adding the lengths of the first lens (1) through the ninth lens (9) (whereby the lengths of the first prism (L1) and the second prism (L2) must be adjusted back to their actual lengths). The zoom magnification is calculated by adding an ideal image plane with a focal length A mm according to this design, which changes the focal length of the new optical system to B mm; the zoom magnification is therefore B / A. Compared to conventional telephoto lenses, the optical design of this lens uses a larger number of lenses, enabling further volume compression and increased performance.

[0032] The present utility model discloses a telephoto lens for external attachment to mobile phones, featuring an integrated design. Compared to conventional external telephoto lenses for mobile phones, this lens offers a shorter length and reduced weight while providing the same zoom magnification. When the telephoto lens is externally attached to a mobile phone, no additional tripod support is required to ensure stable image capture, thus improving portability. Furthermore, the design demonstrates a significant increase in image sharpness; when shooting at a defined distance, the sharpness perceived by the user is at least twice as sharp compared to shooting without an external lens on the mobile phone.

[0033] It is clear that the foregoing embodiments are merely illustrative and do not limit the possible embodiments. The person skilled in the art could easily imagine other variations or modifications in various forms based on the above description. There is neither the need nor the possibility to exhaust all embodiments here. The obvious modifications or variations thus derived remain within the scope of protection of the utility model.

Claims

[1] Telephoto lens for external attachment to mobile phones, characterized by , that the physical mechanical length of the telephoto lens is less than 12 mm per magnification factor in relation to the zoom magnification; where the physical mechanical length of the telephoto lens is defined as the distance from the front cover of the telephoto lens to the front of the mobile phone lens when the telephoto lens is attached to the mobile phone; where the specified zoom magnification is defined as B / A per magnification factor, where A is the original focal length of the mobile phone lens and B is the total focal length after attaching the external telephoto lens to the mobile phone. [2] Telephoto lens for external attachment to mobile phones according to claim 1, characterized by, that the telephoto lens comprises a first lens group (G1), second lens group (G2), prism group (L), third lens group (G3) and fourth lens group (G4) arranged successively along the beam path from the object side to the image side; wherein the focal lengths of all lens groups satisfy the following conditions: 1.5 <f(G1) / f(G2)<3; 1.2 <f(G3) / f(G4)<2,4; 0.1 <f(G3 −G4) / f(G1−G4)<0,5; where f(G1) denotes the focal length of the first lens group (G1), f(G2) the focal length of the second lens group (G2), f(G3) the focal length of the third lens group (G3), f(G4) the focal length of the fourth lens group (G4), f(G3-G4) the combined focal length from the third lens group (G3) to the fourth lens group (G4) and f(G1-G4) the combined focal length from the first lens group (G1) to the fourth lens group (G4). [3] Telephoto lens for external attachment to mobile phones according to claim 2, characterized by, that all lenses in the first lens group (G1), the second lens group (G2), the third lens group (G3) and the fourth lens group (G4) are spherical lenses. [4] Telephoto lens for external attachment to mobile phones according to claim 2, characterized by , that the first lens group (G1) comprises a first lens (1) and a second lens (2) arranged along the optical axis from the object side to the image side in this order; wherein the first lens (1) is a spherical lens with a positive focal length and the second lens (2) is a spherical lens with a negative focal length. [5] Telephoto lens for external attachment to mobile phones according to claim 2, characterized by, that the second lens group (G2) comprises a third lens (3) and a fourth lens (4) arranged along the optical axis from the object side to the image side in this order; wherein the third lens (3) is a spherical lens with a positive focal length and the fourth lens (4) is a spherical lens with a negative focal length. [6] Telephoto lens for external attachment to mobile phones according to claim 2, characterized by , that the third lens group (G3) includes a fifth lens (5), wherein the fifth lens (5) is a spherical lens with a positive focal length. [7] Telephoto lens for external attachment to mobile phones according to claim 2, characterized by, that the fourth lens group (G4) is arranged along the optical axis from the object side to the image side in the following order: sixth lens (6), seventh lens (7), eighth lens (8) and ninth lens (9); wherein the sixth lens (6) is a spherical lens with a positive focal length, the seventh lens (7) is a spherical lens with a negative focal length, the eighth lens (8) is a spherical lens with a positive focal length and the ninth lens (9) is a spherical lens with a negative focal length. [8] Telephoto lens for external attachment to mobile phones according to claim 2, characterized by , that the prism group (L) includes at least one prism. [9] Telephoto lens for external attachment to mobile phones according to claim 2, characterized by , that all lenses in the first lens group (G1), the second lens group (G2), the third lens group (G3) and the fourth lens group (G4) are optical glasses.

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