A macro lens

Abstract

The application discloses a macro lens, comprising a front lens group, a diaphragm and a rear lens group arranged in sequence from an object side to an image side; wherein the front lens group and the rear lens group both have positive refractive power; a focal length of the lens is f, a focal length of the front lens group is f S1 , and a focal length of the rear lens group is f S2 ; the f S1 , f S2 and f satisfy the following relationship: 0.85<|f S1 / f|<1.15, 1.20<|f S2 / f|<1.65. The lens formed by the application not only has a compact structure, but also can ensure high imaging resolution, low distortion and short working distance, and has good industrial application value.

Description

Technical Field

[0001] This invention relates to the field of machine vision lens technology, and more particularly to a macro lens. Background Technology

[0002] With the continuous upgrading of modern industrial automation and intelligence, the requirements for machine vision systems are also constantly increasing. Especially in the precision manufacturing process, when it is necessary to position and inspect workpieces, the space for such inspection applications is often relatively narrow and the requirements for inspection accuracy are more stringent. This requires the lens to be small enough, the resolution to be as high as possible, the working distance to be as close as possible, and the depth of field to be increased as much as possible to meet the inspection needs.

[0003] However, most of the compact optical lenses currently available on the market are surveillance lenses, with working distances of several meters or even infinity. Meanwhile, the performance of lenses commonly used in industry varies greatly, and they generally suffer from problems such as large distortion and insufficient working distance, which cannot meet the application needs of precision manufacturing.

[0004] Therefore, the development of high-resolution, low-distortion, macro optical lenses is even more urgent.

[0005] The above information is provided as background information only to aid in understanding this disclosure and does not constitute an assertion or admission that any of the above content can be used as prior art relative to this disclosure. Summary of the Invention

[0006] This invention provides a macro lens to address the shortcomings of existing technologies.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A macro lens includes a front lens group S1, an aperture T, and a rear lens group S2 arranged sequentially from the object side to the image side; wherein,

[0009] Both the front lens group S1 and the rear lens group S2 have positive optical power.

[0010] The focal length of the lens is f, and the focal length of the front lens group S1 is f. S1 The focal length of the rear lens group S2 is f. S2 The f S1 f S2 Each of them satisfies the following relationship with f:

[0011] 0.85<|f S1 / f|<1.15, 1.20<|f S2 / f|<1.65.

[0012] Furthermore, in the macro lens, the front lens group S1 includes a first lens G1, a second lens G2, and a third lens G3 arranged sequentially from the object plane to the image plane;

[0013] The first lens G1 has positive optical power and is a meniscus structure;

[0014] The second lens G2 has positive optical power and is a biconvex structure;

[0015] The third lens G3 has negative optical power and is a biconcave structure;

[0016] The second lens G2 and the third lens G3 are cemented together to form a first cemented lens U1 with negative optical power.

[0017] Furthermore, in the macro lens, the rear lens group S2 includes a fourth lens G4, a fifth lens G5, a sixth lens G6, and a seventh lens G7 arranged sequentially from the object plane to the image plane;

[0018] The fourth lens G4 has negative optical power and is a biconcave structure;

[0019] The fifth lens G5 has positive optical power and is a biconvex structure;

[0020] The sixth lens G6 has negative optical power and is a meniscus structure;

[0021] The seventh lens G7 has positive optical power;

[0022] The fourth lens G4 and the fifth lens G5 are cemented together to form a second cemented lens U2 with positive optical power.

[0023] Furthermore, in the macro lens, the distance L from the vertex of the front surface of the first lens G1 to the vertex of the rear surface of the seventh lens G7 satisfies the following relationship with f:

[0024] |L / f|>0.50.

[0025] Furthermore, in the macro lens, the optical back intercept BFL from the vertex of the rear surface of the seventh lens G7 to the image plane satisfies the following relationship with f:

[0026] |BFL / f| < 1.35.

[0027] Furthermore, in the macro lens, the half-image height y' of the lens and f satisfy the following relationship:

[0028] |y' / f|<0.35.

[0029] Furthermore, in the macro lens, the focal length of the first lens G1 is f. G1The f G1 The following relationship is satisfied with f:

[0030] 0.80 < |f G1 / f|<1.25.

[0031] Furthermore, in the macro lens, the focal length of the first cemented lens U1 is f. U1 The f U1 The following relationship is satisfied with f:

[0032] 2.10 < |f U1 / f|<2.80;

[0033] The focal length of the second cemented lens U2 is f U2 The f U2 The following relationship is satisfied with f:

[0034] 2.20 < |f U2 / f|<4.50.

[0035] Furthermore, in the macro lens, the focal length of the sixth lens G6 is f. G6 The f G6 The following relationship is satisfied with f:

[0036] 1.00 < |f G6 / f|<1.35;

[0037] The focal length of the seventh lens G7 is f G7 The f G7 The following relationship is satisfied with f:

[0038] 0.75 < |f G7 / f|<1.20.

[0039] Furthermore, in the macro lens, the first lens G1, the second lens G2, the third lens G3, the fourth lens G4, the fifth lens G5, the sixth lens G6, and the seventh lens G7 are all spherical mirrors;

[0040] The seventh lens G7 has a meniscus structure or a biconvex structure.

[0041] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0042] The macro lens provided in this invention uses optical elements such as a front lens group and a rear lens group arranged sequentially from the object plane to the image plane, and rationally configures the optical power of each lens group and the focal length relationship between the lens and each lens group. This results in a lens that is not only compact in structure, but also ensures high imaging resolution, low distortion, and short working distance, thereby meeting the needs of industrial applications and having great value for adoption and promotion. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the structure of a macro lens provided in an embodiment of the present invention;

[0045] Figure 2 This is an optical distortion curve diagram of a macro lens provided in an embodiment of the present invention;

[0046] Figure 3 This is another structural schematic diagram of a macro lens provided in an embodiment of the present invention. Detailed Implementation

[0047] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0048] In the description of this invention, it should be understood that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be an intermediate component present simultaneously. When a component is considered to be "set" on another component, it can be directly set on the other component or there may be an intermediate component present simultaneously.

[0049] Furthermore, terms such as “long,” “short,” “inner,” and “outer” indicate orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings. They are used only for the purpose of describing the present invention and are not intended to indicate or imply that the device or component referred to must have this specific orientation or operate in a specific orientational configuration. Therefore, they should not be construed as limitations of the present invention.

[0050] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0051] Example 1

[0052] In view of the aforementioned deficiencies in existing macro optical lenses, the applicant, based on years of extensive practical experience and professional knowledge in the design and manufacture of such products, and in conjunction with the application of theoretical principles, has actively conducted research and innovation in order to create a technology that can overcome the deficiencies in the existing technology, making macro optical lenses more practical. After continuous research, design, and repeated prototype production and improvements, this invention, which has real practical value, has finally been created.

[0053] Please refer to Figure 1 This invention provides a macro lens, comprising a front lens group S1, an aperture T, and a rear lens group S2 arranged sequentially from the object side to the image side; wherein,

[0054] Both the front lens group S1 and the rear lens group S2 have positive optical power.

[0055] The focal length of the lens is f, and the focal length of the front lens group S1 is f. S1 The focal length of the rear lens group S2 is f. S2 The f S1 f S2 Each of them satisfies the following relationship with f:

[0056] 0.85<|f S1 / f|<1.15, 1.20<|f S2 / f|<1.65.

[0057] It should be noted that the above structure can realize a macro lens with a focal length of 35mm, an image-side F-number of 2.8, a maximum imaging surface of φ17.6mm, and a resolution of 145lp / mm. This means that with the largest corresponding imaging chip, the pixel count can reach 12 million pixels, and the maximum optical distortion across the entire field of view is less than 0.10%. Specifically... Figure 2 As shown, Figure 2 This is the optical distortion curve of the lens. The lens uses a full-group focusing system, enabling it to achieve sharp imaging at relatively close working distances, with a minimum working distance of 70mm.

[0058] Please refer to this again. Figure 1 In this embodiment, the front lens group S1 includes a first lens G1, a second lens G2 and a third lens G3 arranged sequentially from the object plane to the image plane;

[0059] The first lens G1 has positive optical power and is a meniscus structure;

[0060] The second lens G2 has positive optical power and is a biconvex structure;

[0061] The third lens G3 has negative optical power and is a biconcave structure;

[0062] The second lens G2 and the third lens G3 are cemented together to form a first cemented lens U1 with negative optical power.

[0063] Preferably, the rear lens group S2 includes a fourth lens G4, a fifth lens G5, a sixth lens G6, and a seventh lens G7 arranged sequentially from the object plane to the image plane;

[0064] The fourth lens G4 has negative optical power and is a biconcave structure;

[0065] The fifth lens G5 has positive optical power and is a biconvex structure;

[0066] The sixth lens G6 has negative optical power and is a meniscus structure;

[0067] The seventh lens G7 has positive optical power;

[0068] The fourth lens G4 and the fifth lens G5 are cemented together to form a second cemented lens U2 with positive optical power.

[0069] Preferably, the distance L from the vertex of the front surface of the first lens G1 to the vertex of the rear surface of the seventh lens G7 satisfies the following relationship with f:

[0070] |L / f|>0.50.

[0071] Preferably, the optical back intercept BFL from the vertex of the rear surface of the seventh lens G7 to the image plane satisfies the following relationship with f:

[0072] |BFL / f| < 1.35.

[0073] Preferably, the half-image height y' of the lens and f satisfy the following relationship:

[0074] |y' / f|<0.35.

[0075] Preferably, the focal length of the first lens G1 is f. G1 The f G1 The following relationship is satisfied with f:

[0076] 0.80 < |f G1 / f|<1.25.

[0077] Preferably, the focal length of the first cemented lens U1 is f. U1 The f U1The following relationship is satisfied with f:

[0078] 2.10 < |f U1 / f|<2.80;

[0079] The focal length of the second cemented lens U2 is f U2 The f U2 The following relationship is satisfied with f:

[0080] 2.20 < |f U2 / f|<4.50.

[0081] Preferably, the focal length of the sixth lens G6 is f. G6 The f G6 The following relationship is satisfied with f:

[0082] 1.00 < |f G6 / f|<1.35;

[0083] The focal length of the seventh lens G7 is f G7 The f G7 The following relationship is satisfied with f:

[0084] 0.75 < |f G7 / f|<1.20.

[0085] Preferably, the first lens G1, the second lens G2, the third lens G3, the fourth lens G4, the fifth lens G5, the sixth lens G6, and the seventh lens G7 are all spherical mirrors.

[0086] In this embodiment, the specific structure of the seventh lens G7 can be implemented in different ways, and each implementation will be described in detail below:

[0087] In the first implementation, such as Figure 1 As shown, the seventh lens G7 has a meniscus structure;

[0088] For example, the specific data of each optical element in the lens can be shown in Table 1 below:

[0089] Table 1:

[0090]

[0091] In this embodiment, the focal length of the lens, i.e., f, is 35mm, and the maximum aperture is F#=2.8. The focal length f of the front lens group S1 is... s1 =37.68mm, the focal length f of the rear lens group S2 S2=50.11mm, the distance L from the vertex of the front surface of the first lens G1 to the vertex of the rear surface of the seventh lens G7 is 25mm, the optical back intercept BFL is 37.2mm, the half image height y' is 8.8mm, and the focal length f of the first lens G1 is... G1 =31.97mm, the focal length f of the first cemented lens U1 U1 =-79.91mm, the focal length f of the second cemented lens U2 U2 =136.7mm, the focal length f of the sixth lens G6 G6 =-39mm, the focal length f of the seventh lens G7 G7 =31.02mm.

[0092] The specific relational expressions are: |f S1 / f|=1.08;|f S2 / f|=1.43; |L / f|=0.71; |BFL / f|=1.06; |y' / f|=0.25; |f G1 / f|=0.91;|f U1 / f|=2.28;|f U2 / f|=3.91;|f G6 / f|=1.11;|f G7 / f|=0.89;

[0093] As can be seen, the above results satisfy the following relationship: 0.85 < |f S1 / f|<1.15; 1.20<|f S2 / f|<1.65; |L / f|>0.50; |BFL / f|<1.35; |y' / f|<0.35; 0.80<|f G1 / f| < 1.25; 0.80 < |f G1 / f| < 1.25; 2.10 < |f U1 / f| < 2.80; 2.20 < |f U2 / f| < 4.50; 1.00 < |f G6 / f| < 1.35; 0.75 < |f G7 / f|<1.20.

[0094] In the second implementation, such as Figure 3 As shown, the seventh lens G7 has a biconvex structure;

[0095] For example, the specific data of each optical element in the lens can be shown in Table 2 below:

[0096] Table 2:

[0097]

[0098] In this embodiment, the focal length of the lens, i.e., f, is 35mm, and the maximum aperture is F#=2.8. The focal length f of the front lens group S1 is... s1 =37.72mm, the focal length f of the rear lens group S2 S2 =53.57mm, the distance L from the vertex of the front surface of the first lens G1 to the vertex of the rear surface of the seventh lens G7 is 25mm, the optical back intercept BFL is 36.91mm, the half image height y' is 8.8mm, and the focal length f of the first lens G1 is... G1 =32.22mm, the focal length f of the first cemented lens U1 U1 =-95.93mm, the focal length f of the second cemented lens U2 U2 =93.93mm, the focal length f of the sixth lens G6 G6 =-44.42mm, the focal length f of the seventh lens G7 G7 =38.78mm.

[0099] The specific relational expressions are: |f S1 / f|=1.02;|f S2 / f|=1.53; |L / f|=0.71; |BFL / f|=1.05; |y' / f|=0.25; |f G1 / f|=0.92;|f U1 / f|=2.74;|f U2 / f|=2.68;|f G6 / f|=1.27;|f G7 / f|=1.11;

[0100] As can be seen, the above results satisfy the following relationship: 0.85 < |f S1 / f|<1.15; 1.20<|f S2 / f|<1.65; |L / f|>0.50; |BFL / f|<1.35; |y' / f|<0.35; 0.80<|f G1 / f| < 1.25; 0.80 < |f G1 / f| < 1.25; 2.10 < |f U1 / f| < 2.80; 2.20 < |f U2 / f| < 4.50; 1.00 < |f G6 / f| < 1.35; 0.75 < |f G7 / f|<1.20.

[0101] Although the terms "front lens group" and "rear lens group" are used frequently in this document, the possibility of using other terms is not excluded. These terms are used merely for the convenience of describing and explaining the essence of the invention; interpreting them as any additional limitation would contradict the spirit of the invention.

[0102] The macro lens provided in this invention uses optical elements such as a front lens group and a rear lens group arranged sequentially from the object plane to the image plane, and rationally configures the optical power of each lens group and the focal length relationship between the lens and each lens group. This results in a lens that is not only compact in structure, but also ensures high imaging resolution, low distortion, and short working distance, thereby meeting the needs of industrial applications and having great value for adoption and promotion.

[0103] In summary, after reading this detailed disclosure, those skilled in the art will understand that the foregoing detailed disclosure is presented by way of example only and is not restrictive. Although not explicitly stated herein, those skilled in the art will understand that this application is intended to encompass various reasonable changes, improvements, and modifications to the embodiments. These changes, improvements, and modifications are intended to be made by this application and are within the spirit and scope of the exemplary embodiments of this application.

[0104] Furthermore, certain terms used in this application have been used to describe embodiments of this application. For example, "an embodiment," "an embodiment," and / or "some embodiments" mean that a particular feature, structure, or characteristic described in connection with that embodiment may be included in at least one embodiment of this application. Therefore, it is to be emphasized and understood that two or more references to "an embodiment" or "an embodiment" or "an alternative embodiment" in various parts of this specification do not necessarily refer to the same embodiment. Moreover, specific features, structures, or characteristics may be appropriately combined in one or more embodiments of this application.

[0105] It should be understood that in the foregoing description of the embodiments of this application, various features are combined in a single embodiment, drawing, or description for the purpose of simplifying the understanding of a feature. However, this does not mean that the combination of these features is necessary, and those skilled in the art may extract some features as separate embodiments when reading this application. That is, the embodiments in this application can also be understood as an integration of multiple sub-embodiments. It is also valid when the content of each sub-embodiment contains fewer than all the features of a single foregoing disclosed embodiment.

[0106] Each patent, patent application, publication of the patent application, and other materials such as articles, books, specifications, publications, documents, articles, etc., cited herein may be incorporated by reference. The entire contents used for all purposes, except for any history of prosecution documents associated with it, that may be inconsistent with or conflict with this document, or that may have a limiting effect on the widest extent of the claims, are now or hereafter associated with this document. For example, in the event of any inconsistency or conflict between the description, definition, and / or use of terms associated with any of the included materials and the terms, description, definition, and / or used in connection with this document, the terms used herein shall prevail.

[0107] Finally, it should be understood that the embodiments disclosed herein are illustrative of the principles of the embodiments of this application. Other modified embodiments are also within the scope of this application. Therefore, the embodiments disclosed herein are merely examples and not limitations. Those skilled in the art can adopt alternative configurations to implement the applications in this application based on the embodiments in this application. Therefore, the embodiments of this application are not limited to the embodiments precisely described in the application.

Claims

1. A macro lens, characterized in that, It includes a front lens group (S1), an aperture stop (T), and a rear lens group (S2) arranged sequentially from the object side to the image side; wherein, Both the front lens group (S1) and the rear lens group (S2) have positive optical power; The focal length of the lens is f, and the focal length of the front lens group (S1) is f. S1 The focal length of the rear lens group (S2) is f. S2 The f S1 f S2 Each of them satisfies the following relationship with f: 0.85<|f S1 / f|<1.15,1.20<|f S2 / f|<1.65; The macro lens has a minimum working distance of 70mm and a maximum optical distortion of less than 0.10% across the entire field of view. The front lens group (S1) includes a first lens (G1), a second lens (G2), and a third lens (G3) arranged sequentially from the object plane to the image plane. The first lens (G1) has positive optical power and is a meniscus structure; The second lens (G2) has positive optical power and is a biconvex structure; The third lens (G3) has negative optical power and is a biconcave structure; The second lens (G2) and the third lens (G3) are cemented together to form a first cemented lens (U1) with negative optical power. The rear lens group (S2) includes a fourth lens (G4), a fifth lens (G5), a sixth lens (G6), and a seventh lens (G7) arranged sequentially from the object plane to the image plane. The fourth lens (G4) has negative optical power and is a biconcave structure; The fifth lens (G5) has positive optical power and is a biconvex structure; The sixth lens (G6) has negative optical power and is a meniscus structure; The seventh lens (G7) has positive optical power; The fourth lens (G4) and the fifth lens (G5) are cemented together to form a second cemented lens (U2) with positive optical power. The distance L from the vertex of the front surface of the first lens (G1) to the vertex of the rear surface of the seventh lens (G7) satisfies the following relationship with f: |L / f|>0.50; The optical back intercept BFL from the vertex of the rear surface of the seventh lens (G7) to the image plane satisfies the following relationship with f: |BFL / f| < 1.35; The half-image height y' of the lens and f satisfy the following relationship: |y' / f|<0.

35.

2. The macro lens according to claim 1, characterized in that, The focal length of the first lens (G1) is f G1 The f G1 The following relationship is satisfied with f: 0.80<|f G1 / f|<1.25。 3. The macro lens according to claim 2, characterized in that, The focal length of the first cemented lens (U1) is f. U1 The f U1 The following relationship is satisfied with f: 2.10<|f U1 / f|<2.80; The focal length of the second cemented lens (U2) is f. U2 The f U2 The following relationship is satisfied with f: 2.20<|f U2 / f|<4.50。 4. The macro lens according to claim 3, characterized in that, The focal length of the sixth lens (G6) is f G6 The f G6 The following relationship is satisfied with f: 1.00<|f G6 / f|<1.35; The focal length of the seventh lens (G7) is f G7 The f G7 The following relationship is satisfied with f: 0.75<|f G7 / f|<1.20。 5. The macro lens according to claim 4, characterized in that, The first lens (G1), the second lens (G2), the third lens (G3), the fourth lens (G4), the fifth lens (G5), the sixth lens (G6), and the seventh lens (G7) are all spherical mirrors; The seventh lens (G7) has a meniscus structure or a biconvex structure.

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