External long-focus lens for mobile phones

Abstract

Provides external long-focus lenses for mobile phones. The actual mechanical length / zoom magnification of the long focal length lens is less than 12 mm / times. The long focal length lens includes a first lens group G1, a second lens group G2, a prism group L, a third lens group G3, and a fourth lens group G4, which are arranged in this order from the object side to the image side along the optical path. The focal lengths of all the lens groups are 1.5

Description

[Technical Field]

[0001] The present invention relates to the field of optical lenses, and more particularly to a long focal length lens for external use on mobile phones. [Background technology]

[0002] To improve mobile phone's ability to capture distant details, mobile phone manufacturers are improving the long-focus performance of their lenses. However, due to the size of mobile phones, there is an upper limit to the performance of the original long-focus lens of a mobile phone. When using the original long-focus lens of a mobile phone to photograph distant objects, the clarity of the image is significantly reduced when using the digital zoom function of the mobile phone itself. Therefore, it is necessary to attach an external long-focus lens to the mobile phone to meet the requirements of long-distance, high-definition image capture.

[0003] However, external long-focus lenses have long focal lengths, and accordingly the number of lenses required and the overall length of the optical system are often longer than with ordinary lenses. Currently, external long-focus lenses for mobile phones are generally long and heavy, which makes them prone to shaking when shooting. Therefore, a tripod is required to support the external long-focus lens when in use, which allows for a stable image. Summary of the Invention [Problem to be solved by the invention]

[0004] Therefore, the technical problem that this invention aims to solve is to overcome the technical problem that the long focal length lenses attached to mobile phones in the prior art are large in volume and weight, and the screen is prone to shaking when taking pictures while holding the phone, and thereby provide an external long focal length lens for mobile phones that is easy to carry. [Means for solving the problem]

[0005] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0006] A telephoto lens for external attachment to a mobile phone, wherein the actual mechanical length / zoom ratio of the telephoto lens is < 12 mm / times, where The definition of the actual mechanical length of the telephoto lens is the distance from the front cover of the telephoto lens to the tip of the mobile phone lens when the telephoto lens is externally attached to the mobile phone, The definition of the zoom ratio is B / A times, the original focal length of the mobile phone lens is A, and the overall focal length of both after the telephoto lens is externally attached to the mobile phone is B.

[0007] Furthermore, it includes a first lens group G1, a second lens group, a prism group, a third lens group, and a fourth lens group sequentially arranged from the object side to the image side along the optical path, and the focal lengths of all the lens groups are 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, satisfying the relationship Here, f(G1) represents the focal length of the first lens group, f(G2) represents the focal length of the second lens group, f(G3) represents the focal length of the third lens group, f(G4) represents the focal length of the fourth lens group, f(G3 - G4) represents the combined focal length from the third lens group to the fourth lens group, and f(G1 - G4) represents the combined focal length from the first lens group to the fourth lens group.

[0008] Furthermore, all the lenses in the first lens group, the second lens group, the third lens group, and the fourth lens group are all spherical lenses.

[0009] Furthermore, the first lens group includes a first lens and a second lens sequentially arranged from the object side to the image side along the optical axis, the first lens is a spherical lens with positive power, and the second lens is a spherical lens with negative power.

[0010] Furthermore, the second lens group includes a third lens and a fourth lens arranged sequentially from the object side to the image side along the optical axis, the third lens being a spherical lens with positive power, and the fourth lens being a spherical lens with negative power.

[0011] Furthermore, the third lens group includes a fifth lens, which is a spherical lens with positive power.

[0012] Furthermore, the fourth lens group includes a sixth lens, a seventh lens, an eighth lens, and a ninth lens arranged in sequence from the object side to the image side along the optical axis, the sixth lens being a spherical lens with positive power, the seventh lens being a spherical lens with negative power, the eighth lens being a spherical lens with positive power, and the ninth lens being a spherical lens with negative power.

[0013] Furthermore, the prism group includes at least one prism.

[0014] Furthermore, all of the lenses in the first lens group, the second lens group, the third lens group, and the fourth lens group are optical glass lenses. [Effects of the Invention]

[0015] The technical solution of this invention has the following advantages: Because the actual mechanical length of the long-focus lens / zoom magnification ratio is less than 12 mm / times, the length and weight of the long-focus lens can be shortened while maintaining the same optical zoom ratio; when the long-focus lens is attached to a mobile phone, a stable image can be obtained without the need for an additional tripod to support the long-focus lens; and, in addition, this design has a significant advantage in terms of clarity; for a given object distance, the clarity perceived by the user is at least one-fold higher than the effect of a photograph taken without an external lens attached to the mobile phone. [Brief explanation of the drawings]

[0016] [Figure 1]1 is an equivalent optical path diagram of a long focal length lens for external use in a mobile phone according to a first embodiment of the present invention; [Figure 2A] 1 is a diagram showing the spherical aberration of the external long focal length lens for a mobile phone according to the first embodiment of the present invention; [Figure 2B] 1 is a diagram showing the curvature of field of an external long focal length lens for a mobile phone according to a first embodiment of the present invention; [Figure 2C] 3 is a diagram showing distortion of the external long focal length lens for a mobile phone according to the first embodiment of the present invention; FIG. [Figure 3] 10 is an equivalent optical path diagram of a long focal length lens for external use in a mobile phone according to a second embodiment of the present invention; [Figure 4A] 10 is a diagram showing the spherical aberration of the external long focal length lens for a mobile phone according to the second embodiment of the present invention; FIG. [Figure 4B] FIG. 10 is a diagram showing the curvature of field of the external long focal length lens for a mobile phone according to the second embodiment of the present invention. [Figure 4C] 10 is a diagram showing distortion of the external long focal length lens for a mobile phone according to the second embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0017] In order to more clearly describe the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces drawings that need to be used in the description of the specific embodiments or the prior art. It is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can further derive other drawings based on these drawings without any creative work.

[0018] The following clearly and completely describes the technical solutions of the present invention with reference to the drawings, and it is obvious that the described embodiments are only some of the embodiments of the present invention, not all of the embodiments, and all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without any creative work fall within the scope of protection of the present invention.

[0019] In the description of the present invention, with regard to what needs to be described, the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is merely for facilitating the description of the present invention and simplifying the description. It does not indicate or imply that such a device or element must have a specific orientation and must be structured and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention. Also, the terms "first", "second", "third" are only for the purpose of description and cannot be understood as indicating or suggesting relative importance.

[0020] A telephoto lens for external attachment to a mobile phone shown in FIG. 1, which is mainly used for being externally attached to the lens of a mobile phone. The telephoto lens and the original lens of the mobile phone can cooperate to photograph a distant object and enlarge it on the screen. The actual mechanical length / zoom ratio of the telephoto lens < 12 mm / ×, for example, the actual mechanical length / zoom ratio of the telephoto lens = 10 mm / ×. Here, the definition of the actual mechanical length of the telephoto lens is the distance from the front cover of the telephoto lens to the tip of the mobile phone lens when the telephoto lens is externally attached to the mobile phone and used. The definition of the zoom ratio is B / A×. If the original focal length of the mobile phone lens is A, after the telephoto lens is externally attached to the mobile phone, the focal length after considering the telephoto lens and the mobile phone lens as an integral body is B, and the zoom ratio of the telephoto lens for external attachment to the mobile phone is B / A×.

[0021] As shown in FIG. 1, the telephoto lens includes a first lens group G1, a second lens group G2, a prism group L, a third lens group G3, and a fourth lens group G4 sequentially arranged from the object side to the image side along the optical axis. The focal lengths of all the lens groups satisfy 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, Here, f(G1) represents the focal length of the first lens group (G1), f(G2) represents the focal length of the second lens group (G2), f(G3) represents the focal length of the third lens group (G3), f(G4) represents the focal length of the fourth lens group (G4), f(G3-G4) represents the composite focal length from the third lens group (G3) to the fourth lens group (G4), and f(G1-G4) represents the composite focal length from the first lens group (G1) to the fourth lens group (G4).

[0022] In some embodiments of this example, the first lens group G1 includes a first lens 1 and a second lens 2 arranged sequentially from the object side to the image side along the optical axis, the second lens group G2 includes a third lens 3 and a fourth lens 4 arranged sequentially from the object side to the image side along the optical axis, the prism group L includes a first prism L1 and a second prism L2, the third lens group G3 includes a fifth lens 5, and the fourth lens group G4 includes a sixth lens 6, a seventh lens 7, an eighth lens 8, and a ninth lens 9 arranged sequentially from the object side to the image side along the optical axis. Here, the first lens 1 is a spherical lens with positive power, the second lens 2 is a spherical lens with negative power, the third lens 3 is a spherical lens with positive power, the fourth lens 4 is a spherical lens with negative power, the fifth lens 5 is a spherical lens with positive power, the sixth lens 6 is a spherical lens with positive power, the seventh lens 7 is a spherical lens with negative power, the eighth lens 8 is a spherical lens with positive power, and the ninth lens 9 is a spherical lens with negative power. Here, 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 all optical glass lenses. The penultimate plane of the optical path is a mobile phone model P of the original lens of a mobile phone, which is used to combine the two and evaluate the performance after actually attaching an external long focal length lens.

[0023] In some other embodiments of this embodiment, the number of lenses in the long focal length lens is not limited to nine, and the number of lenses in the long focal length lens may vary, as long as the composite optical focal length of each lens group in the long focal length lens satisfies the mathematical relationship described above.

[0024] In some embodiments of this embodiment, the adjacent surfaces of the first lens 1 and the second lens 2 are cemented together, and the adjacent surfaces of the seventh lens 7 and the eighth lens 8 are cemented together. The cemented lens combination can effectively correct chromatic aberration, making the colors of the captured image more realistic. The combination of the spherical doublet lenses is cemented. As an alternative embodiment, based on the concept of the present invention, in order to distinguish it from the present application, the above combination method may be modified to a combination method such as bonding or integral molding, and the lens shape after combination may also be adaptively modified, which is also within the scope of protection of the present application. For a single lens or two consecutive power lenses with the same sign, the single lens can be divided into two or more lenses, or two consecutive lenses with the same sign can be combined into one lens. In this way, a simple transformation can be made to the optical structure of the patent, for example, to allocate the power of the transformed lens or lens group within the mathematical relationship range of the patent. Based on this embodiment, the number of lenses and the combination method may be changed or replaced to distinguish it from the present application, provided that it does not deviate from the gist of the present application, and all of them fall within the scope of protection of the present application.

[0025] As shown in Figures 2A, 2B, and 2C, Figure 2A is a spherical aberration diagram of the long focal length lens in the first embodiment of this example, Figure 2B is a field curvature diagram of the long focal length lens in the first embodiment of this example, and Figure 2C is a distortion diagram of the long focal length lens in the first embodiment of this example. As can be seen from the curves in the figures, the spherical aberration is basically less than ±0.1, which ensures clarity at the center of the image, the field curvature is basically less than ±0.1, which ensures similar clarity across a large field of view screen, and the distortion is less than 3%, which ensures small deformations on the captured image.

[0026] Table 1 below lists the actual parameters of each lens of the long focal length lens in the first embodiment according to the above mathematical relationships. [Table 1]

[0027] In the first embodiment of this example, the focal lengths of the first lens 1 to the ninth lens 9 are distributed as follows: f(1-2) / f(3-4)=1.9755, f(5) / f(6-9)=1.784, The relationship f(5-9) / f(1-9)=0.2032 is satisfied. Here, f(mn) is the composite focal length from the mth lens to the nth lens, m and n are both positive integers, and 1≦m <n≦9である。

[0028] Table 2 below lists the actual parameters of each lens of the long focal length lens in the second embodiment according to the above mathematical relationships. [Table 2]

[0029] Referring to FIG. 3, in the second embodiment of this example, the focal lengths of the first lens 1 to the ninth lens 9 are distributed as follows: f(1-2) / f(3-4)=2.6885, f(5) / f(6-9)=1.6386, The relationship f(5-9) / f(1-9)=0.2009 is satisfied. Here, f(mn) is the composite focal length from the mth lens to the nth lens, m and n are both positive integers, and 1≦m <n≦9である。

[0030] As shown in Figures 4A, 4B, and 4C, Figure 4A is a spherical aberration diagram of the long focal length lens in the second embodiment of this example, Figure 4B is a field curvature diagram of the long focal length lens in the second embodiment of this example, and Figure 4C is a distortion diagram of the long focal length lens in the second embodiment of this example. As can be seen from the curves in the figures, the spherical aberration is basically less than ±0.1, which ensures clarity at the center of the image, the field curvature is basically less than ±0.1, which ensures similar clarity across a large field of view screen, and the distortion is less than 3%, which ensures small deformations on the captured image.

[0031] The relational expressions for the focal lengths in the first and second long focal length lenses are shown in Table 3 below. [Table 3]

[0032] Here, the actual mechanical length of the long focal length lens is the axial length of the long focal length lens, and is calculated by accumulating the total length from the first lens 1 to the ninth lens 9 in the optical path design of the long focal length lens (here, the first prism L1 and the second prism L2 need to be converted to actual lengths). The zoom magnification is calculated by adding an ideal surface with a focal length of A mm after the design, so that the focal length of the new optical system becomes B mm, and the zoom magnification is B / A times. The lens optical design of this application uses more lenses than conventional long focal length lenses, further reducing the volume and improving performance.

[0033] The external long-focus lens for mobile phones provided by this invention adopts an integrated design, which shortens the length and weight of the long-focus lens compared to conventional external long-focus lenses for mobile phones while maintaining the same optical zoom ratio. When used externally, the long-focus lens can be stabilized without the need for a tripod to support the long-focus lens, making it more portable. Furthermore, this design has a significant advantage in clarity, and for a given object distance, the clarity perceived by the user is at least one-fold higher than the effect when shooting without an external lens on the mobile phone.

[0034] It should be understood that the above examples are merely illustrative and do not limit the embodiments. Those skilled in the art can make other different modifications or variations based on the above description. It is not possible or necessary to comprehensively list all embodiments here. Any obvious modifications or variations derived therefrom are still within the scope of protection of the invention and creation. [Explanation of symbols]

[0035] G1 First lens group G2 Second lens group G3 Third lens group G4 4th 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 9th lens L Prism Group L1 First prism L2 Second prism P mobile phone model

Claims

1. A long focal length lens for external attachment to a mobile phone, the actual mechanical length / zoom magnification of said long focal length lens being <12mm / times, wherein: The definition of the actual mechanical length of the long focal length lens is the distance from the front cover of the long focal length lens to the tip of the lens of the mobile phone when the long focal length lens is externally attached to the mobile phone; The definition of the zoom magnification is B / A times, the original focal length of the lens for the mobile phone is A, and the total focal length of both after the long focal length lens is attached to the mobile phone is B.

2. The optical system includes a first lens group (G1), a second lens group (G2), a prism group (L), a third lens group (G3), and a fourth lens group (G4), which are arranged in this order from the object side to the image side along the optical path, and the focal lengths of all the lens groups are 1.5<f(G1) / f(G2)<3, 1.2<f(G3) / f(G4)<2.4, The relationship 0.1<f(G3-G4) / f(G1-G4)<0.5 is satisfied, Here, f(G1) represents the focal length of the first lens group (G1), f(G2) represents the focal length of the second lens group (G2), f(G3) represents the focal length of the third lens group (G3), f(G4) represents the focal length of the fourth lens group (G4), f(G3-G4) represents the composite focal length from the third lens group (G3) to the fourth lens group (G4), and f(G1-G4) represents the composite focal length from the first lens group (G1) to the fourth lens group (G4).

3. 3. The external long focal length lens for a mobile phone according to claim 2, wherein all of the 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. The long focal length lens for external use on a mobile phone as described in claim 2, characterized in that the first lens group (G1) includes a first lens (1) and a second lens (2) arranged sequentially from the object side to the image side along the optical axis, the first lens (1) being a spherical lens with positive power, and the second lens (2) being a spherical lens with negative power.

5. The long focal length lens for external use on a mobile phone as described in claim 2, characterized in that the second lens group (G2) includes a third lens (3) and a fourth lens (4) arranged sequentially from the object side to the image side along the optical axis, the third lens (3) being a spherical lens with positive power, and the fourth lens (4) being a spherical lens with negative power.

6. The external long focal length lens for a mobile phone according to claim 2, characterized in that the third lens group (G3) includes a fifth lens (5), which is a spherical lens with a positive power.

7. The fourth lens group (G4) includes a sixth lens (6), a seventh lens (7), an eighth lens (8), and a ninth lens (9) arranged in sequence from the object side to the image side along the optical axis, wherein the sixth lens (6) is a spherical lens with positive power, the seventh lens (7) is a spherical lens with negative power, the eighth lens (8) is a spherical lens with positive power, and the ninth lens (9) is a spherical lens with negative power. A long focal length lens for external attachment to a mobile phone as described in claim 2.

8. 3. The external long focal length lens for a mobile phone according to claim 2, wherein the prism group (L) includes at least one prism.

9. 3. The external long focal length lens for a mobile phone according to claim 2, wherein all of the 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 glass lenses.

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