Modular high-magnification telecentric lens group

Abstract

The application relates to the technical field of imaging optical systems and device design, and discloses a modular high-magnification telecentric lens group. The modular high-magnification telecentric lens group comprises a common modular front group, a diaphragm T and a plurality of rear groups with different combined focal lengths; the diaphragm T is arranged at a combined focal length focal point of the common modular front group, the common modular front group has a fixed combined focal length f 100 , and the common modular front group can be matched with each rear group to form a telecentric lens group with different magnifications. The modular high-magnification telecentric lens group provided by the application can form telecentric lens groups with different magnifications by selecting rear groups with different combined focal lengths according to use requirements based on the common lens front group, so that the modular design of the high-magnification lens is realized; only a rear group with a small number of lenses needs to be replaced to realize different magnification requirements, thereby effectively reducing the development difficulty and improving the cost efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of imaging optical system and device design, and particularly relates to a modular high-magnification telecentric lens group. BACKGROUND

[0002] In a precise optical measurement system, using a common industrial lens can cause the following problems: the change of object distance can cause the difference of magnification, parallax, large distortion, etc., which is difficult to meet the requirements of high-precision detection, while the telecentric lens can reduce or even eliminate the above problems. It can make the image magnification not change with the change of object distance within a certain object distance range. Its principle advantage makes it very suitable for precise measurement and detection field.

[0003] However, most of the existing telecentric lenses have fixed magnification. In actual application, the sizes of the objects to be measured are different in different application scenarios, and there are many items to be detected. Therefore, a series of telecentric lenses with different magnifications need to be designed to cope with it. If the telecentric lens can be modularized or some components can be shared, not only the production cost can be effectively reduced, but also the research and development difficulty can be reduced, different non-standard projects can be quickly responded to, and the efficiency can be improved. The patent with publication number "CN219417848U" and the name "Telecentric lens and mechanical vision detection equipment" discloses a telecentric lens. By changing the face type and material of the first lens, the eighth lens and the ninth lens, two magnification lenses of 0.64 times and 0.91 times are realized. However, it only achieves the sharing of part of the lenses and does not realize the modularization. The development of high-magnification telecentric lenses is difficult and expensive. At present, there is no modular high-magnification telecentric lens on the market.

[0004] In summary, it is a technical problem to be solved in the field to develop a modular high-magnification telecentric lens.

[0005] The above information is given as background information only to assist with an understanding of the present disclosure, and does not determine or acknowledge whether any of the above is applicable as prior art with respect to the present disclosure. SUMMARY

[0006] The purpose of the present application is to provide a modular high-magnification telecentric lens group to solve or at least partially solve the technical problems existing in the prior art.

[0007] To achieve this purpose, the present application adopts the following technical solutions:

[0008] The present application provides a modular high-magnification telecentric lens group, which comprises a common module front group, a diaphragm T and a plurality of rear groups with different combined focal lengths.

[0009] The diaphragm T is placed at the combined focal length focal point of the common module front group, and the common module front group has a fixed combined focal length f100 The common module front group can be matched with each of the rear groups to form telecentric lens groups with different magnifications. 100 WD satisfy the relationship: 0.3<|f 100 / WD|<0.7.

[0010] Optionally, the common module front group comprises, in order from the object side to the image side, a first lens with positive refractive power, a second lens with positive refractive power, a third lens with positive refractive power, a fourth lens with negative refractive power, a fifth lens with positive refractive power, a sixth lens with negative refractive power, and a seventh lens with positive refractive power, wherein the third lens and the fourth lens form a cemented lens U11 with negative refractive power, and the fifth lens and the sixth lens form a cemented lens U12 with positive refractive power.

[0011] The focal length of the first lens is f 110 , the focal length of the second lens is f 120 , the focal length of the cemented lens U11 is f U11 , the focal length of the cemented lens U2 is f U12 , and the focal length of the seventh lens is f 170 :

[0012] f 100 and f 110 satisfy the relationship: 0.25<|f 100 / f 110 |<0.65.

[0013] f 110 and f 120 satisfy the relationship: 0.75<|f 110 / f 120 |<1.25.

[0014] f 100 and f U11 satisfy the relationship: |f 100 / f U11 |<0.7.

[0015] f 100 and f U12 satisfy the relationship: |f 100 / f U12 |<0.25.

[0016] f 100 and f 170 satisfy the relationship: 0.3<|f 100 / f 170 |<0.9.

[0017] Optionally, the third lens has a refractive index Nd3 and an Abbe number Vd3, and Nd3 and Vd3 satisfy the following relationships respectively: 1.42 < Nd3 < 1.55, 70 < Vd3 < 95.

[0018] The seventh lens has a refractive index Nd7 and an Abbe number Vd7, and Nd7 and Vd7 satisfy the following relationships respectively: 1.48 < Nd7 < 1.65, 65 < Vd7 < 95.

[0019] Optionally, the plurality of rear groups with different combined focal lengths include a first rear group with negative optical power, a second rear group with negative optical power, and a third rear group with negative optical power.

[0020] The common module front group is matched with the first rear group to form a telecentric lens group with a 2x magnification, the common module front group is matched with the second rear group to form a telecentric lens group with a 3x magnification, and the common module front group is matched with the third rear group to form a telecentric lens group with a 4x magnification.

[0021] Optionally, the first rear group includes, arranged in order from the object side to the image side, an eighth lens with negative optical power, a ninth lens with positive optical power, and a tenth lens with negative optical power, wherein the ninth lens and the tenth lens form a cemented lens U21.

[0022] The combined focal length of the first rear group is f 200 , the focal length of the eighth lens 210 is f 210 , and the focal length of the cemented lens U21 is f U21 .

[0023] f 210 and f 200 satisfy the relationship: |f 210 / f 200 | < 0.15.

[0024] f U21 and f 200 satisfy the relationship: |f U21 / f 200 | < 0.2.

[0025] Optionally, the second rear group includes, arranged in order from the object side to the image side, an eleventh lens with negative optical power, a twelfth lens with positive optical power, and a thirteenth lens with negative optical power, wherein the twelfth lens and the thirteenth lens form a cemented lens U31.

[0026] The combined focal length of the second rear group is f 300 , the focal length of the eleventh lens is f 310 , and the focal length of the cemented lens U31 is f U31 .

[0027] f 310 and f 300 satisfy the relationship: 0.25<|f 310 / f 300 |<0.75;

[0028] f U31 and f 300 satisfy the relationship: |f U31 / f 300 |>1.

[0029] Optionally, the third rear group comprises a fourteenth lens with negative optical power, a fifteenth lens with positive optical power, and a sixteenth lens with negative optical power, wherein the fifteenth lens and the sixteenth lens form a cemented lens U41;

[0030] The combined focal length of the third rear group is f 400 , the focal length of the fourteenth lens is f 410 , and the focal length of the cemented lens U41 is f U41 ;

[0031] f 410 and f 400 satisfy the relationship: 0.5<|f 400 / f 410 |<1.5;

[0032] f U41 and f 400 satisfy the relationship: |f U41 / f 400 |>10.

[0033] Optionally, in the common module front group, the first lens, the second lens, the third lens, and the fifth lens are all double convex lenses, the fourth lens and the sixth lens are all double concave lenses, and the seventh lens is a meniscus lens;

[0034] In the first rear group, the ninth lens is a double convex lens, and the tenth lens is a double concave lens; in the second rear group, the twelfth lens is a double convex lens, and the thirteenth lens is a double concave lens; in the third rear group, the fifteenth lens is a double convex lens, and the sixteenth lens is a double concave lens.

[0035] Optionally, a half-transmission half-reflection prism is further arranged between the seventh lens and the diaphragm T;

[0036] One of the rear groups is arranged on the refractive path and the reflection path of the half-transmission half-reflection prism, respectively; wherein another diaphragm is further arranged on the reflection path of the common module front group;

[0037] The diaphragm T is arranged at the combined focal point of the front group of the common module on the refractive path.

[0038] Optionally, a half-reflection prism is arranged between the seventh lens and the diaphragm T.

[0039] The rear group is arranged on the refractive path of the half-reflection prism, and the coaxial illumination light source is arranged on the reflection path of the half-reflection prism.

[0040] The diaphragm T is arranged at the combined focal point of the front group of the common module on the refractive path.

[0041] Compared with the prior art, the present application has the following beneficial effects:

[0042] The modular high-magnification telecentric lens group provided by the present application forms a telecentric lens group with different magnification by selecting a rear group with different combined focal lengths according to the use requirement through the common lens front group, so that the modular design of the high-magnification lens is realized.

[0043] The present application has other characteristics and advantages, which will be apparent or will be described in detail in the accompanying drawings and subsequent specific embodiments incorporated herein, which together serve to explain the specific principles of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description are only some embodiments of the present application, and those skilled in the art can also obtain other accompanying drawings according to these accompanying drawings without creative labor.

[0045] Figure 1 is a structural schematic diagram of a modular high-magnification telecentric lens group provided by an embodiment of the present application.

[0046] Figure 2 is an image-side MTF curve diagram of the optical system in Embodiment 1.

[0047] Figure 3 is a structural schematic diagram of another modular high-magnification telecentric lens group provided by an embodiment of the present application.

[0048] Figure 4Figure 6 is a graph of the image-side MTF curve for the optical system of Example 2.

[0049] Figure 5 Figure 7 is a schematic diagram of another modular high-magnification telecentric lens provided by an embodiment of the present application.

[0050] Figure 6 Figure 8 is a graph of the image-side MTF curve for the optical system of Example 3. DETAILED DESCRIPTION

[0051] To make possible application scenarios, technical principles, specific schemes that can be implemented, purposes and effects that can be achieved, the following specific embodiments are combined with the accompanying drawings to make a detailed description. The embodiments described herein are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0052] In this paper, the term "embodiment" means that the specific features, structures or characteristics described in conjunction with the embodiment can be included in at least one embodiment of the present application. The term "embodiment" appearing at various places in the specification does not necessarily refer to the same embodiment, and does not particularly limit its independence or association with other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, the technical features mentioned in each embodiment can be combined in any way to form a corresponding implementable technical solution.

[0053] Unless otherwise defined, the meanings of the technical terms used herein are the same as those commonly understood by those skilled in the art to which the present application belongs; the use of related terms herein is only for the purpose of describing specific embodiments, and is not intended to limit the present application.

[0054] In the description of the present application, the phrase "and / or" is a description of the logical relationship between the objects, which means that there can be three relationships, for example, A and / or B, which means that there are three cases: A exists, B exists, and A and B exist at the same time. In addition, the character " / " in this paper generally represents that the associated objects before and after are a "or" logical relationship.

[0055] In the present application, such as "first" and "second", the terms are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual quantity, primary and secondary or order relationship between the entities or operations.

[0056] In the present application, the terms "comprise", "contain", "include", or other similar phrases as used in a clause means to encompass the non-exclusive inclusion, and the terms do not exclude the presence of additional elements in the process, method, or product comprising the stated elements, so that the process, method, or product comprising a series of elements can not only include those defined elements, but also include other elements not explicitly listed, or also include elements inherent to such process, method, or product.

[0057] In the present application, the terms "greater than", "less than", "exceed", and the like are understood as not including the number; the terms "above", "below", "within", and the like are understood as including the number. In addition, in the description of the embodiments of the present application, the meaning of "multiple" is two or more (including two), and similar expressions related to "multiple" are also understood in this way, for example, "multiple groups", "multiple times", and the like, unless otherwise explicitly specified.

[0058] In the description of the embodiments of the present application, the spatial-related expressions used, such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "perpendicular", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship based on the orientation or positional relationship shown in the specific embodiments or the drawings, and are only for the convenience of describing the specific embodiments of the present application or for the reader to understand, and do not indicate or imply that the indicated device or component must have a specific position, a specific orientation, or be constructed or operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0059] Unless otherwise explicitly specified or limited, in the description of the embodiments of the present application, the terms "mount", "connect", "connect", "fix", "set", and the like should be interpreted broadly. For example, the "connection" can be a fixed connection, or a detachable connection, or an integral setting; it can be a mechanical connection, or an electrical connection, or a communication connection; it can be directly connected, or indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art to which the present application belongs, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0060] Please refer to Figure 1 , Figure 3 and Figure 5 , Figure 1 is a structural schematic diagram of a modular high-magnification telecentric lens group provided by the embodiments of the present application, Figure 3is a structural schematic diagram of another modular high-magnification telecentric lens group provided by an embodiment of the present application, Figure 5 is a structural schematic diagram of still another modular high-magnification telecentric lens group provided by an embodiment of the present application.

[0061] As shown in Figure 1 , Figure 3 or Figure 5 indicated, the modular high-magnification telecentric lens group comprises a common module front group 100, a stop T and a plurality of rear groups with different combined focal lengths;

[0062] The stop T is placed at the combined focal length focal point of the common module front group 100, the common module front group 100 has a fixed combined focal length f 100 , and the common module front group 100 can be matched with each rear group to form a telecentric lens group with different magnifications; the working distance of the telecentric lens group is WD, f 100 and WD satisfy the relationship: 0.3<|f 100 / WD|<0.7.

[0063] Specifically, the common module front group 100 comprises, arranged in order from the object side to the image side, a first lens 110 with positive refractive power, a second lens 120 with positive refractive power, a third lens 130 with positive refractive power, a fourth lens 140 with negative refractive power, a fifth lens 150 with positive refractive power, a sixth lens 160 with negative refractive power and a seventh lens 170 with positive refractive power, wherein the third lens 130 and the fourth lens 140 form a cemented lens U11 with negative refractive power, and the fifth lens 150 and the sixth lens 160 form a cemented lens U12 with positive refractive power;

[0064] The focal length of the first lens 110 is f 110 , the focal length of the second lens 120 is f 120 , the focal length of the cemented lens U11 is f U11 , the focal length of the cemented lens U2 is f U12 , and the focal length of the seventh lens 170 is f 170 :

[0065] f 100 and f 110 satisfy the relationship: 0.25<|f 100 / f 110 |<0.65;

[0066] f 110 and f 120 satisfy the relationship: 0.75<|f 110 / f 120 |<1.25;

[0067] f 100 and fU11 satisfies the relationship: |f 100 / f U11 |<0.7;

[0068] f 100 and f U12 satisfies the relationship: |f 100 / f U12 |<0.25;

[0069] f 100 and f 170 satisfies the relationship: 0.3<|f 100 / f 170 |<0.9.

[0070] According to the above relationships, the first lens 110 and the second lens 120 in the common module front group 100 have similar focal lengths, can better share the ability to deflect light, can reduce the light incidence angle, reduce the off-axis aberration, at the same time, form a smaller spherical aberration, provide a good foundation for the subsequent aberration correction, in addition, it is also beneficial to reduce the tolerance sensitivity. The cemented lens U12 has a small optical power, which is beneficial to correct high-order aberrations, and the negative optical power formed by the cemented surface further corrects the spherical aberration; the seventh lens 170 tends to be bent towards the stop structure, which can reduce the spherical aberration.

[0071] Further, the refractive index of the third lens 130 is Nd3, and the Abbe number is Vd3, Nd3 and Vd3 satisfy the relationship: 1.42<Nd3<1.55, 70<Vd3<95 respectively;

[0072] The refractive index of the seventh lens 170 is Nd7, and the Abbe number is Vd7, Nd7 and Vd7 satisfy the relationship: 1.48<Nd7<1.65, 65<Vd7<95 respectively.

[0073] Using the lens combination satisfying the above refractive index and dispersion relationship is more beneficial to correct the system chromatic aberration and reduce the design difficulty of the rear group.

[0074] In the embodiment, the rear groups with different focal lengths described above include a first rear group 200 with negative optical power, a second rear group 300 with negative optical power, and a third rear group 400 with negative optical power;

[0075] The common module front group 100 is matched with the first rear group 200, which can form a telecentric lens group with a 2x magnification; the common module front group 100 is matched with the second rear group 300, which can form a telecentric lens group with a 3x magnification; the common module front group 100 is matched with the third rear group 400, which can form a telecentric lens group with a 4x magnification.

[0076] Specifically, as Figure 1As shown, the first rear group 200 includes an eighth lens 210 with negative optical power, a ninth lens 220 with positive optical power, and a tenth lens 230 with negative optical power arranged sequentially from the object side to the image side, wherein the ninth lens 220 and the tenth lens 230 form a cemented lens U21.

[0077] The combined focal length of the first rear group 200 is f. 200 The focal length of the eighth lens 210 is f. 210 The focal length of the cemented lens U21 is f. U21 ;

[0078] f 210 and f 200 Satisfy the relation: |f 210 / f 200 |<0.15;

[0079] f U21 and f 200 Satisfy the relation: |f U21 / f 200 |<0.2.

[0080] Specifically, such as Figure 3 As shown, the second rear group 300 includes an eleventh lens 310 with negative optical power, a twelfth lens 320 with positive optical power, and a thirteenth lens 330 with negative optical power arranged sequentially from the object side to the image side, wherein the twelfth lens 320 and the thirteenth lens 330 form a cemented lens U31.

[0081] The combined focal length of the second rear group 300 is f. 300 The focal length of the eleventh lens 310 is f. 310 The focal length of the cemented lens U31 is f. U31 ;

[0082] f 310 and f 300 The relation is satisfied: 0.25 < |f 310 / f 300 |<0.75;

[0083] f U31 and f 300 Satisfy the relation: |f U31 / f 300 |>1.

[0084] Specifically, such as Figure 5 As shown, the third rear group 400 includes a fourteenth lens 410 with negative optical power, a fifteenth lens 420 with positive optical power, and a sixteenth lens 430 with negative optical power, wherein the fifteenth lens 420 and the sixteenth lens 430 form a cemented lens U41.

[0085] The combined focal length of the third rear group 400 is f 400 The focal length of the fourteenth lens 410 is f 410 The focal length of the cemented lens U41 is f U41 ;

[0086] f 410 and f 400 satisfy the relationship: 0.5<|f 400 / f 410 |<1.5;

[0087] f U41 and f 400 satisfy the relationship: |f U41 / f 400 |>10.

[0088] More specifically, in the common module front group 100, the first lens 110, the second lens 120, the third lens 130 and the fifth lens 150 are all double convex lenses, the fourth lens 140 and the sixth lens 160 are both double concave lenses, and the seventh lens 170 is a meniscus lens.

[0089] In the first rear group 200, the ninth lens 220 is a double convex lens, and the tenth lens 230 is a double concave lens; in the second rear group 300, the twelfth lens 320 is a double convex lens, and the thirteenth lens 330 is a double concave lens; in the third rear group 400, the fifteenth lens 420 is a double convex lens, and the sixteenth lens 430 is a double concave lens.

[0090] In this embodiment, the optical axes of all lenses are on a predetermined optical axis; the aperture of the diaphragm S is a circular hole, and the center of the circular hole is on the predetermined optical axis.

[0091] It can be understood that the aperture value of the diaphragm S needs to be adjusted according to the specific application scenario.

[0092] As an optional implementation, a semi-transmissive semi-reflective prism is further arranged between the seventh lens 170 and the diaphragm T;

[0093] A rear group is arranged on the refractive path and the reflection path of the semi-transmissive semi-reflective prism respectively; wherein another diaphragm is further arranged on the reflection path of the common module front group 100;

[0094] The diaphragm T is arranged at the combined focal length focal point of the common module front group 100 on the refractive path; and the other diaphragm is arranged at the combined focal length focal point of the common module front group 100 on the reflection path.

[0095] As another optional implementation, a semi-transmissive semi-reflective prism is further arranged between the seventh lens 170 and the diaphragm T;

[0096] A rear group is set on the refraction path of the semi-transparent and semi-reflective prism; a coaxial illumination source is set on the reflection path of the semi-transparent and semi-reflective prism.

[0097] The aperture T is located at the focal point of the combined focal length in the front group 100 of the common module, which is on the refraction path.

[0098] The following three specific embodiments are given to explain the telecentric lens group formed by combining the aforementioned shared module front group 100 with the first rear group 200, the second rear group 300, and the third rear group 400:

[0099] Example 1:

[0100] In Embodiment 1, the first rear group 200 and the shared module front group 100 can form a telecentric lens with a magnification of 2x. The lens data of each lens in the telecentric lens group are shown in Table 1 below:

[0101] Table 1

[0102]

[0103]

[0104] It should be noted that in Table 1, "front surface" corresponds to... Figure 1 The left surface of the lens or lens group corresponds to the middle surface, while the rear surface corresponds to the middle surface. Figure 1 The right side surface of the corresponding lens or lens group; or it can be understood as: the object surface in Figure 1 On the left, the image plane (or image surface) is... Figure 1 On the right side, the surface closer to the object is called the "front surface", and the surface closer to the image is called the "back surface".

[0105] In Embodiment 1, the combined focal length f of the shared module front group 100 is... 100 =60mm; Focal length f of the first lens 110 110 =129mm, the focal length f of the second lens is 120. 120 =135mm, the focal length f of the cemented lens U11 U11 = -95mm, focal length f of cemented lens U12 U12 =358mm, the focal length f of the seventh lens is 170. 170 =97mm. The combined focal length f of the first rear group of 200mm. 200 = -437mm, the focal length f of the eighth lens 210 210 = -36mm, the focal length f of the cemented lens U21 U21 =74mm.

[0106] In Example 1, the optical parameters of the telecentric lens group are shown in Table 2 below:

[0107] Table 2

[0108] Working distance WD 114 mm Numerical aperture NA 0.12 Resolution 3 microns Magnification 2x Target surface 1.1 inch Telecentricity <0.1° Distortion <0.1％

[0109] In Table 2, the formula for calculating the resolution is 0.65*λ / NA, where λ is the wavelength.

[0110] like Figure 2 As shown, Figure 2 The image-side MTF (Modulation Transfer Function) curve of the optical system in Example 1 is shown.

[0111] Example 2:

[0112] In Embodiment 2, the second rear group 300 and the shared module front group 100 can form a telecentric lens with a magnification of 3x. The lens data of each lens in the telecentric lens group are shown in Table 3 below:

[0113] Table 3

[0114]

[0115]

[0116] In Example 2, the combined focal length f of the shared module front group 100 100 =60mm; Focal length f of the first lens 110 110 =129mm, the focal length f of the second lens is 120. 120＝ 135mm, the focal length f of the cemented lens U11 U11 = -95mm, focal length f of cemented lens U12 U12 =358mm, the focal length f of the seventh lens is 170. 170 =97mm. The combined focal length f of the rear 300mm group. 300 = -57mm, the focal length f of the eleventh lens 310 310 = -27mm, focal length f of cemented lens U31 U31 =101mm.

[0117] In Example 2, the optical parameters of the telecentric lens group are shown in Table 4 below:

[0118] Table 4

[0119] Working distance WD 114 mm Numerical aperture NA 0.13 Resolution 2.75 microns Magnification 3x Target surface 1.1 inch Telecentricity <0.1° Distortion <0.1％

[0120] In Table 4, the formula for calculating resolution is 0.65*λ / NA, where λ is the wavelength.

[0121] like Figure 4 As shown, Figure 4 This is the image-side MTF curve of the optical system in Example 2.

[0122] Example Three:

[0123] In Example Three, the third rear group 400 and the common module front group 100 can constitute a telecentric lens with 4 times magnification, and the lens data of the telecentric lens group is shown in Table Five below:

[0124] Table Five

[0125]

[0126]

[0127] In Example Three, the combined focal length f of the common module front group 100 is 60mm; the focal length f of the first lens 110 is 129mm, the focal length f of the second lens 120 is 135mm, the focal length f of the cemented lens U11 is -95mm, the focal length f of the cemented lens U12 is 358mm, the focal length f of the seventh lens 170 is 97mm. The combined focal length f of the rear group 400 is -36mm, the focal length f of the fourteenth lens 410 is -38mm, the focal length f of the cemented lens U41 is -549mm. 100 110 120 U11 U12 170 400 410 U41

[0128] In Example Three, the optical parameters of the telecentric lens group are shown in Table Six below:

[0129] Table Six

[0130]

[0131]

[0132] In Table Six, the calculation formula of the resolution is 0.65*λ / NA, and λ is the wavelength.

[0133] As shown in Figure 6, the image-side MTF curve of the optical system in Example Three is shown. Figure 6 Figure 6

[0134] ​​​​​​​​​​​In summary, compared with existing technologies, the modular high-magnification telecentric lens group provided in this application, by sharing a front lens group and selecting rear groups with different focal length combinations according to usage requirements, forms a telecentric lens group with different magnifications, such as 2.0x, 3.0x, 4.0x, etc., realizing a modular design of high-magnification lenses; only the rear lens group with a smaller number of lenses needs to be replaced to meet different magnification requirements, effectively reducing the difficulty of research and development, reducing the maintenance and upgrade costs of the telecentric lens group, and improving cost-effectiveness.

[0135] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A modular high-magnification telecentric lens group, characterized by, The common module front group (100), an aperture T and a plurality of different combination focal length rear groups are combined; A diaphragm T is placed at the combined focal point of the common front group (100) with a fixed combined focal length f 100 , which can be matched with each of the rear groups to form telecentric lens groups with different magnifications; the working distance of the telecentric lens group is WD, f 100 and WD satisfy the relationship: 0.3<|f 100 / WD|<0.7; The common module front group (100) is composed of a first lens (110) with positive refractive power, a second lens (120) with positive refractive power, a third lens (130) with positive refractive power, a fourth lens (140) with negative refractive power, a fifth lens (150) with positive refractive power, a sixth lens (160) with negative refractive power and a seventh lens (170) with positive refractive power arranged in order from the object side to the image side, wherein the third lens (130) and the fourth lens (140) form a cemented lens U11 with negative refractive power, and the fifth lens (150) and the sixth lens (160) form a cemented lens U12 with positive refractive power; The focal length of the first lens (110) is f 110 The focal length of the second lens (120) is f 120 The focal length of the cemented lens U1 is f U11 The focal length of the cemented lens U2 is f U12 The focal length of the seventh lens (170) is f 170 : f 100 and f 110 satisfying the relation: 0.25<|f 100 / f 110 <0.65; f 110 and f 120 satisfying the relation: 0.75<|f 110 / f 120 <1.25; f 100 and f U11 satisfies the relation: |f 100 / f U11 |<0.7; f 100 and f U12 satisfies the relation: |f 100 / f U12 | < 0.25; f 100 and f 170 satisfies the relation: 0.3<|f 100 / f 170 <0.9; The plurality of different combination focal length rear groups are composed of a first rear group (200) with negative refractive power, a second rear group (300) with negative refractive power and a third rear group (400) with negative refractive power; The first rear group (200) is composed of an eighth lens (210) with negative refractive power, a ninth lens (220) with positive refractive power and a tenth lens (230) with negative refractive power arranged in order from the object side to the image side; The second rear group (300) is composed of an eleventh lens (310) with negative refractive power, a twelfth lens (320) with positive refractive power and a thirteenth lens (330) with negative refractive power arranged in order from the object side to the image side; The third rear group (400) is composed of a fourteenth lens (410) with negative refractive power, a fifteenth lens (420) with positive refractive power and a sixteenth lens (430) with negative refractive power.

2. The modular high-magnification telecentric lens group according to claim 1, characterized in that, The refractive index of the third lens (130) is Nd3, and the Abbe number is Vd3, and Nd3 and Vd3 satisfy the relationship: 1.42 < Nd3 < 1.55, 70 < Vd3 < 95 respectively; The refractive index of the seventh lens (170) is Nd7, and the Abbe number is Vd7, and Nd7 and Vd7 satisfy the relationship: 1.48 < Nd7 < 1.65, 65 < Vd7 < 95 respectively.

3. The modular high magnification telecentric lens group according to claim 1, wherein the common module front group (100) and the first rear group (200) are combined to form a 2x magnification telecentric lens group; the common module front group (100) and the second rear group (300) are combined to form a 3x magnification telecentric lens group; and the common module front group (100) and the third rear group (400) are combined to form a 4x magnification telecentric lens group. The ninth lens (220) and the tenth lens (230) form a cemented lens U21; 4. The modular high-magnification telecentric lens group according to claim 3, characterized in that, The twelfth lens (320) and the thirteenth lens (330) form a cemented lens U31; The combined focal length of the first rear group (200) is f 200 The focal length of the eighth lens 210 is f 210 The focal length of the cemented lens U21 is f U21 ; f 210 and f 200 satisfies the relation: |f 210 / f 200 | < 0.15; f U21 and f 200 satisfies the relation: |f U21 / f 200 | < 0.

2.

5. The modular high-magnification telecentric lens group according to claim 4, characterized in that, The fifteenth lens (420) and the sixteenth lens (430) form a cemented lens U41; The combined focal length of the second rear group (300) is f 300 The focal length of the eleventh lens (310) is f 310 The focal length of the cemented lens U31 is f U31 ; f 310 and f 300 satisfies the relation: 0.25 < |f 310 / f 300 < 0.75; f U31 and f 300 satisfies the relation: |f U31 / f 300 |>1.

6. The modular high-magnification telecentric lens group according to claim 5, characterized in that, ​ The combined focal length of the third rear group (400) is f 400 The focal length of the fourteenth lens (410) is f 410 The focal length of the cemented lens U41 is f U41 ; f 410 and f 400 satisfying the relation: 0.5<|f 400 / f 410 |<1.5; f U41 and f 400 satisfies the relationship: |f U41 / f 400 |>10.

7. The modular high-magnification telecentric lens group according to claim 6, characterized in that, The first lens (110), the second lens (120), the third lens (130) and the fifth lens (150) are all double convex lenses, the fourth lens (140) and the sixth lens (160) are all double concave lenses, and the seventh lens (170) is a meniscus lens in the common module front group (100); The ninth lens (220) is a double convex lens and the tenth lens (230) is a double concave lens in the first rear group (200); the twelfth lens (320) is a double convex lens and the thirteenth lens (330) is a double concave lens in the second rear group (300); the fifteenth lens (420) is a double convex lens and the sixteenth lens (430) is a double concave lens in the third rear group (400).

8. The modular high-magnification telecentric lens set according to claim 1, wherein, A half-transmission half-reflection prism is further arranged between the seventh lens (170) and the diaphragm T; One of the rear groups is arranged on the refractive path and the reflection path of the half-transmission half-reflection prism respectively; wherein another diaphragm is further arranged on the reflection path of the common module front group (100); The diaphragm T is arranged at the combined focal length focal point of the common module front group (100) on the refractive path; and the other diaphragm is arranged at the combined focal length focal point of the common module front group (100) on the reflection path.

9. The modular high-magnification telecentric lens set according to claim 1, wherein, A half-transmission half-reflection prism is further arranged between the seventh lens (170) and the diaphragm T; One of the rear groups is arranged on the refractive path of the half-transmission half-reflection prism; and a coaxial illumination light source is arranged on the reflection path of the half-transmission half-reflection prism; The diaphragm T is arranged at the combined focal length focal point of the common module front group (100) on the refractive path.

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