Modularized high-magnification telecentric lens group

Abstract

The invention relates to the technical field of imaging optical system and device design, and discloses a modular high-magnification telecentric lens group. The modularized high-magnification telecentric lens group comprises a common module front group, a diaphragm T and a plurality of rear groups with different combined focal lengths, a diaphragm T is placed at a combined focal length focus of the front group of the common module, the front group of the common module has a fixed combined focal length f100, and the front group of the common module can be respectively matched with the rear groups to form telecentric lens groups with different amplification factors. According to the modular high-magnification telecentric lens group provided by the invention, the lens front group is shared, and the rear groups with different combined focal lengths are selected according to use requirements, so that the telecentric lens group with different magnifications is formed, and the modular design of the high-magnification lens is realized; and the requirement of different amplification factors can be realized only by replacing the rear group with a small number of lenses, so that the research and development difficulty is effectively reduced, and the cost benefit is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of imaging optical systems and device design, and particularly to a modular high-magnification telecentric lens group. Background Art

[0002] In a precision optical measurement system, using an ordinary industrial lens will have problems such as different magnification caused by the change of object distance, parallax, and large distortion, which are difficult to meet the requirements of high-precision detection. While a telecentric lens can reduce or even eliminate the above problems. It can make the obtained image magnification not change with the change of object distance within a certain object distance range. Its principle advantage makes it very suitable for the fields of precision measurement and detection.

[0003] However, most of the existing telecentric lenses have a fixed magnification. In practical applications, the sizes of the items to be measured in different application scenarios are different, and there are also many items to be detected. Therefore, a series of telecentric lenses with different magnifications need to be designed to cope with them. The patent with the publication number "CN219417848U" and the name "Telecentric Lens and Machine Vision Detection Equipment" discloses a telecentric lens, which realizes two magnification lenses of 0.64 times and 0.91 times respectively by changing the surface shapes and materials of the first lens, the eighth lens, and the ninth lens. However, it only achieves the sharing of some lenses and does not realize modularization. The development of high-magnification telecentric lenses is difficult and expensive, and there is currently no modular high-magnification telecentric lens on the market.

[0004] In summary, developing a modular high-magnification telecentric lens has become an urgent technical problem in this field.

[0005] The above information is given as background information only to assist in understanding the present disclosure, and it is not determined or admitted whether any of the above content can be used as prior art relative to the present disclosure. Summary of the Invention

[0006] The purpose of the present invention 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 invention adopts the following technical solutions:

[0008] The present invention provides a modular high-magnification telecentric lens group, including a common module front group, a diaphragm T, and several rear groups with different combined focal lengths;

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

[0010] Optionally, the front group of the common module includes a first lens with a positive optical power, a second lens with a positive optical power, a third lens with a positive optical power, a fourth lens with a negative optical power, a fifth lens with a positive optical power, a sixth lens with a negative optical power, and a seventh lens with a positive optical power, which are arranged in sequence from the object side to the image side. Among them, the third lens and the fourth lens form a cemented lens U11 with a negative optical power, and the fifth lens and the sixth lens form a cemented lens U12 with a positive optical 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 , 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 refractive index of the third lens is Nd3 The Abbe number is Vd 3 Nd 3 and Vd 3 respectively satisfy the relational expressions: 1.42 < Nd 3 < 1.55, 70 < Vd 3 < 95;

[0018] The refractive index of the seventh lens is Nd 7 and the Abbe number is Vd 7 Nd 7 and Vd 7 respectively satisfy the relational expressions: 1.48 < Nd 7 < 1.65, 65 < Vd 7 < 95.

[0019] Optionally, the rear group with several different combined focal lengths includes a first rear group with a negative optical power, a second rear group with a negative optical power, and a third rear group with a negative optical power;

[0020] The front group of the common module is paired with the first rear group to form a telecentric lens group with a magnification of 2 times; the front group of the common module is paired with the second rear group to form a telecentric lens group with a magnification of 3 times; the front group of the common module is paired with the third rear group to form a telecentric lens group with a magnification of 4 times.

[0021] Optionally, the first rear group includes an eighth lens with a negative optical power, a ninth lens with a positive optical power, and a tenth lens with a negative optical power, which are arranged in sequence from the object side to the image side. Among them, 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 The focal length of the cemented lens U21 is f U21 ;

[0023] f 210 and f 200 satisfy the relational expression: |f 210 / f 200 | < 0.15;

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

[0025] Optionally, the second rear group includes an eleventh lens with negative focal power, a twelfth lens with positive focal power, and a thirteenth lens with negative focal power, which are arranged in sequence from the object side to the image side. Among them, 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 relational expression: 0.25 < |f 310 / f 300 | < 0.75;

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

[0029] Optionally, the third rear group includes a fourteenth lens with negative focal power, a fifteenth lens with positive focal power, and a sixteenth lens with negative focal power. Among them, 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 relational expression: 0.5 < |f 400 / f 410 | < 1.5;

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

[0033] Optionally, in the front group of the common module, the first lens, the second lens, the third lens, and the fifth lens are all biconvex lenses, the fourth lens and the sixth lens are both biconcave lenses, and the seventh lens is a meniscus lens;

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

[0035] Optionally, a semi-transmissive and semi-reflective prism is further disposed between the seventh lens and the diaphragm T;

[0036] One of the rear groups is respectively disposed on the refraction path and the reflection path of the semi-transmissive and semi-reflective prism; wherein, another diaphragm is further disposed on the reflection path of the front group of the common module;

[0037] Wherein, the diaphragm T is disposed at the combined focal length focus of the front group of the common module on the refraction path; the other diaphragm is disposed at the combined focal length focus of the front group of the common module on the reflection path.

[0038] Optionally, a semi-transmissive and semi-reflective prism is further disposed between the seventh lens and the diaphragm T;

[0039] One of the rear groups is disposed on the refraction path of the semi-transmissive and semi-reflective prism; on the reflection path of the semi-transmissive and semi-reflective prism, a coaxial illumination light source is disposed;

[0040] Wherein, the diaphragm T is disposed at the combined focal length focus of the front group of the common module on the refraction path.

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

[0042] The modular high-magnification telecentric lens group provided by the present invention forms a telecentric lens group with different magnification ratios by sharing the front group of the lens and selecting rear groups with different combined focal lengths according to the use requirements, realizing the modular design of the high-magnification lens; in the design, only the rear group with fewer lenses needs to be replaced to meet the requirements of different magnification ratios, effectively reducing the R & D difficulty and improving the cost effectiveness.

[0043] The present invention has other characteristics and advantages, which will be obvious from the accompanying drawings incorporated herein and the subsequent detailed description, or will be described in detail in the accompanying drawings incorporated herein and the subsequent detailed description, and these accompanying drawings and detailed description are used together to explain the specific principles of the present invention. Description of the Drawings

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

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

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

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

[0048] Figure 4 It is the image - side MTF curve graph of the optical system in Embodiment 2.

[0049] Figure 5 It is a schematic structural diagram of yet another modular high - magnification telecentric lens group provided by an embodiment of the present invention.

[0050] Figure 6 It is the image - side MTF curve graph of the optical system in Embodiment 3. Detailed implementation manners

[0051] To illustrate in detail the possible application scenarios, technical principles, specific implementable solutions, achievable purposes and effects of the present application, the following is described in detail with reference to the specific embodiments listed and in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of the present application, so they are only examples and cannot be used to limit the protection scope of the present application.

[0052] Referring to "embodiment" in this text means that the specific features, structures or characteristics described in connection with the embodiment may be included in at least one embodiment of the present application. The term "embodiment" appearing at various positions in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or relevance to 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 corresponding implementable technical solutions.

[0053] Unless otherwise defined, the meanings of the technical terms used in this text are the same as those generally understood by those skilled in the technical field to which the present application belongs; the use of the relevant terms in this text is only for describing specific embodiments and is not intended to limit the present application.

[0054] In the description of the present application, the term "and / or" is an expression used to describe the logical relationship between objects, indicating that there can be three relationships. For example, A and / or B means: there is A, there is B, and there is both A and B at the same time. In addition, the character " / " in this text generally represents an "or" logical relationship between the associated objects before and after.

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

[0056] Without further limitations, in this application, the expressions "including", "comprising", "having", or other similar expressions used in a statement are intended to cover non-exclusive inclusion. These expressions do not exclude the possibility that there may be additional elements in the process, method, or product that includes the said elements. Thus, in a process, method, or product that includes a series of elements, it may include not only those defined elements, but also other elements not explicitly listed, or elements inherent to such a process, method, or product.

[0057] Similar to the understanding in the "Examination Guidelines", in this application, expressions such as "greater than", "less than", "exceeding", etc. are understood not to include the recited number; expressions such as "above", "below", "within", etc. are understood to include the recited number. In addition, in the description of the embodiments of this application, the meaning of "a plurality of" is two or more (including two). Similar expressions related to "many", such as "multiple groups", "multiple times", etc., are understood in the same way, unless otherwise specifically and clearly defined.

[0058] In the description of the embodiments of this application, the spatially 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", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the specific embodiment or the drawing. This is only for the convenience of describing the specific embodiments of this application or for the reader's understanding, and does not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, it should not be construed as a limitation on the embodiments of this application.

[0059] Unless otherwise clearly specified or limited, in the description of the embodiments of this application, the terms "installed", "connected", "joined", "fixed", "set", etc. should be understood in a broad sense. For example, the said "connection" can be a fixed connection, a detachable connection, or an integral setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be directly connected, or indirectly connected through an intermediate medium; it can be the communication inside two elements or the interaction relationship between two elements. For those skilled in the art to which this application pertains, the specific meanings of the above terms in the embodiments of this application can be understood according to specific circumstances.

[0060] Please refer toFigure 1 , Figure 3 and Figure 5 , Figure 1 are schematic structural diagrams of a modular high-magnification telecentric lens group provided by an embodiment of the present invention, Figure 3 is a schematic structural diagram of another modular high-magnification telecentric lens group provided by an embodiment of the present invention, Figure 5 is a schematic structural diagram of yet another modular high-magnification telecentric lens group provided by an embodiment of the present invention.

[0061] As Figure 1 , Figure 3 or Figure 5 shown, the modular high-magnification telecentric lens group includes a common module front group 100, a diaphragm T, and several rear groups with different combined focal lengths;

[0062] The diaphragm T is placed at the combined focal length focus 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 respectively combined with each rear group to form telecentric lens groups with different magnification ratios; the working distance of the telecentric lens group is WD, and f 100 and WD satisfy the relationship: 0.3 < |f 100 / WD| < 0.7.

[0063] Specifically, the common module front group 100 includes a first lens 110 with positive optical power, a second lens 120 with positive optical power, a third lens 130 with positive optical power, a fourth lens 140 with negative optical power, a fifth lens 150 with positive optical power, a sixth lens 160 with negative optical power, and a seventh lens 170 with positive optical power, which are arranged in sequence from the object side to the image side. Among them, the third lens 130 and the fourth lens 140 form a cemented lens U11 with negative optical power, and the fifth lens 150 and the sixth lens 160 form a cemented lens U12 with positive optical 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 120Satisfy the relational expression: 0.75 < |f 110 / f 120 | < 1.25;

[0067] f 100 and f U11 Satisfy the relational expression: |f 100 / f U11 | < 0.7;

[0068] f 100 and f U12 Satisfy the relational expression: |f 100 / f U12 | < 0.25;

[0069] f 100 and f 170 Satisfy the relational expression: 0.3 < |f 100 / f 170 | < 0.9.

[0070] According to the above relational expressions, the first lens 110 and the second lens 120 in the front group 100 of the common module have similar focal lengths, can better share the ability to deflect light, can reduce the light incident angle, reduce the off-axis aberration, and at the same time form a smaller spherical aberration, providing 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 correcting the high-order aberration, and at the same time uses the negative optical power formed by the cemented surface to further correct the spherical aberration; the seventh lens 170 tends to be bent towards the aperture stop structure, which can reduce the spherical aberration and coma aberration.

[0071] Furthermore, the refractive index of the third lens 130 is Nd 3 , and the Abbe number is Vd 3 , Nd 3 and Vd 3 respectively satisfy the relational expressions: 1.42 < Nd 3 < 1.55, 70 < Vd 3 < 95;

[0072] The refractive index of the seventh lens 170 is Nd 7 , and the Abbe number is Vd 7 , Nd 7 and Vd 7 respectively satisfy the relational expressions: 1.48 < Nd 7 < 1.65, 65 < Vd 7 < 95.

[0073] Using a lens combination that satisfies the above refractive index and dispersion relationships is more conducive to correcting the chromatic aberration of the system and reducing the design difficulty of the rear group.

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

[0075] The front group 100 of the common module is paired with the first rear group 200 to form a telecentric lens group with a magnification of 2 times; the front group 100 of the common module is paired with the second rear group 300 to form a telecentric lens group with a magnification of 3 times; the front group 100 of the common module is paired with the third rear group 400 to form a telecentric lens group with a magnification of 4 times.

[0076] Specifically, as Figure 1 shown, the first rear group 200 includes an eighth lens 210 with a negative optical power, a ninth lens 220 with a positive optical power, and a tenth lens 230 with a negative optical power arranged in sequence from the object side to the image side. Among them, 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 , and the focal length of the cemented lens U21 is f U21 ;

[0078] f 210 and f 200 satisfy the relationship: |f 210 / f 200 | < 0.15;

[0079] f U21 and f 200 satisfy the relationship: |f U21 / f 200 | < 0.2.

[0080] Specifically, as Figure 3 shown, the second rear group 300 includes an eleventh lens 310 with a negative optical power, a twelfth lens 320 with a positive optical power, and a thirteenth lens 330 with a negative optical power arranged in sequence from the object side to the image side. Among them, 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 , and the focal length of the cemented lens U31 is f U31 ;

[0082] f 310 and f 300 satisfy the relationship: 0.25 < |f 310 / f 300 | < 0.75;

[0083] f U31 and f 300 satisfy the relationship: |f U31 / f 300 |> 1.

[0084] Specifically, as Figure 5 shown, the third rear group 400 includes a fourteenth lens 410 with a negative optical power, a fifteenth lens 420 with a positive optical power, and a sixteenth lens 430 with a negative optical power. Among them, 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 , and 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 biconvex lenses, the fourth lens 140 and the sixth lens 160 are both biconcave lenses, and the seventh lens 170 is a meniscus lens;

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

[0090] In this embodiment, the optical axes of all lenses are on the 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 correspondingly according to the specific application scenario.

[0092] As an optional implementation manner, a half - reflecting and half - transmitting prism is further provided between the seventh lens 170 and the diaphragm T;

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

[0094] Wherein, the diaphragm T is arranged at the combined focal length focus of the front group 100 of the common module on the refraction path; another diaphragm is arranged at the combined focal length focus of the front group 100 of the common module on the reflection path.

[0095] As another alternative embodiment, a semi-transmissive semi-reflective prism is also arranged between the seventh lens 170 and the diaphragm T;

[0096] A rear group is arranged on the refraction path of the semi-transmissive semi-reflective prism; on the reflection path of the semi-transmissive semi-reflective prism, a coaxial illumination light source is arranged;

[0097] Wherein, the diaphragm T is arranged at the combined focal length focus of the front group 100 of the common module on the refraction path.

[0098] The following gives three specific embodiments for explanation according to the telecentric lens groups formed by the above-mentioned front group 100 of the common module combined with the first rear group 200, the second rear group 300, and the third rear group 400 respectively:

[0099] Embodiment 1:

[0100] In Embodiment 1, the first rear group 200 and the front group 100 of the common module can form a telecentric lens with a magnification of 2 times. The data of each lens of 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 corresponding lens or lens group, and "rear surface" corresponds to Figure 1 the right surface of the corresponding lens or lens group; or it can be understood that: the object side is on Figure 1 the left, the image side (or image plane) is on Figure 1 the right, the surface closer to the object side is the "front surface", and the surface closer to the image side is the "rear surface".

[0105] In Embodiment 1, the combined focal length f of the front group 100 of the common module 100 = 60mm; the focal length f of the first lens 110 110 = 129mm, the focal length f of the second lens 120 120 = 135mm, the focal length f of the cemented lens U11U11 = -95 mm, the focal length f of the cemented lens U12 U12 = 358 mm, the focal length f of the seventh lens 170 170 = 97 mm. The combined focal length f of the first rear group 200 200 = -437 mm, the focal length f of the eighth lens 210 210 = -36 mm, the focal length f of the cemented lens U21 U21 = 74 mm.

[0106] In Embodiment 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 inches Telecentricity <0.1° Distortion <0.1％

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

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

[0111] Embodiment 2:

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

[0113] Table 3

[0114]

[0115]

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

[0117] In Embodiment 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 inches Telecentricity <0.1° Distortion <0.1％

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

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

[0122] Embodiment 3:

[0123] In Embodiment 3, the third rear group 400 and the front group 100 of the common module can form a telecentric lens with a magnification of 4 times. The lens data of the telecentric lens group are shown in Table 5 below:

[0124] Table 5

[0125]

[0126]

[0127] In Embodiment 3, the combined focal length f of the front group 100 of the common module 100 = 60 mm; the focal length f of the first lens 110 110 = 129 mm, the focal length f of the second lens 120 120 = 135 mm, the focal length f of the cemented lens U11 U11 = -95 mm, the focal length f of the cemented lens U12 U12 = 358 mm, the focal length f of the seventh lens 170 170 = 97 mm. The combined focal length f of the rear group 400 400 = -36 mm, the focal length f of the fourteenth lens 410 410 = -38 mm, the focal length f of the cemented lens U41 U41 = -549 mm.

[0128] In Embodiment 3, the optical parameters of the telecentric lens group are shown in Table 6 below:

[0129] Table 6

[0130]

[0131]

[0132] In Table 6, the resolution calculation formula is 0.65 * λ / NA, where λ is the wavelength.

[0133] As Figure 6 shown Figure 6 is the image-side MTF curve graph of the optical system in Embodiment 3.

[0134] In summary, compared with the prior art, a modular high-magnification telecentric lens group provided by the present application forms a telecentric lens group with different magnification ratios by sharing the front lens group and selecting rear lens groups with different combined focal lengths according to the usage requirements. For example, the magnification ratio of the telecentric lens group can be 2.0x, 3.0x, 4.0x, etc., realizing the modular design of the high-magnification lens; only by replacing the rear lens group with a smaller number of lenses can the requirements of different magnification ratios be achieved, effectively reducing the R & D difficulty, reducing the maintenance and upgrade costs of the telecentric lens group, and improving the cost-effectiveness.

[0135] The above is described. The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions 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 set, characterized in that: It comprises a common module front group (100), an aperture T and a plurality of rear groups with different combined focal lengths; The aperture T is placed at the focus of the combined focal length of the common module front group (100), and the common module front group (100) has a fixed combined focal length f 100 The common module front group (100) can be matched with each of the rear groups 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.

2. A modular high-magnification telecentric lens assembly according to claim 1, characterized in that: The shared module front group (100) comprises a first lens (110) with positive focal power, a second lens (120) with positive focal power, a third lens (130) with positive focal power, a fourth lens (140) with negative focal power, a fifth lens (150) with positive focal power, a sixth lens (160) with negative focal power and a seventh lens (170) with positive focal power, which are arranged in sequence 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 focal power, and the fifth lens (150) and the sixth lens (160) form a cemented lens U12 with positive focal 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 U11 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 Satisfies the relationship: 0.25<|f 100 / f 110 |<0.65; f 110 and f 120 Satisfies the relationship: 0.75<|f 110 / f 120 |<1.25; f 100 and f U11 Satisfies the relationship: |f 100 / f U11 |<0.7; f 100 and f U12 Satisfies the relationship: |f 100 / f U12 |<0.25; f 100 and f 170 Satisfies the relationship: 0.3<|f 100 / f 170 |<0.

9.

3. A modular high-magnification telecentric lens assembly according to claim 2, characterized in that: The refractive index of the third lens (130) is Nd3, and the Abbe number is Vd3. Nd3 and Vd3 respectively satisfy the relationship: 1.42 <Nd3<1.55,70<Vd3<95; The refractive index of the seventh lens (170) is Nd7, and the Abbe number is Vd7. Nd7 and Vd7 respectively satisfy the relationship: 1.48 <Nd7<1.65,65<Vd7<95。 4. The modular high-magnification telecentric lens assembly according to claim 2, characterized in that: The plurality of rear groups with different combined focal lengths 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; The shared module front group (100) and the first rear group (200) can be matched to form a telecentric lens group with a 2-fold magnification; the shared module front group (100) and the second rear group (300) can be matched to form a telecentric lens group with a 3-fold magnification; and the shared module front group (100) and the third rear group (400) can be matched to form a telecentric lens group with a 4-fold magnification.

5. The modular high-magnification telecentric lens assembly according to claim 4, characterized in that: 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, which are arranged in sequence from the object side to the image side, wherein the ninth lens (220) and the tenth lens (230) form a cemented lens U21; 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 relationship: |f 210 / f 200 |<0.15; f U21 and f 200 Satisfies the relationship: |f U21 / f 200 |<0.

2.

6. A modular high-magnification telecentric lens assembly according to claim 5, characterized in that: 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, which are arranged in sequence from the object side to the image side, wherein the twelfth lens (320) and the thirteenth lens (330) form a cemented lens U31; 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 relationship: 0.25<|f 310 / f 300 |<0.75; f U31 and f 300 Satisfies the relationship: |f U31 / f 300 |>1.

7. The modular high-magnification telecentric lens assembly according to claim 6, characterized in that: 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; 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 Satisfies the relationship: 0.5<|f 400 / f 410 |<1.5; f U41 and f 400 Satisfies the relationship: |f U41 / f 400 |>10.

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

9. The modular high-magnification telecentric lens assembly according to claim 2, characterized in that: A semi-transparent and semi-reflective prism is also arranged between the seventh lens (170) and the aperture T; The rear group is respectively arranged on the refraction path and the reflection path of the semi-transparent and semi-reflective prism; wherein another aperture is also arranged on the reflection path of the common module front group (100); The aperture T is arranged at the combined focal length focus of the common module front group (100) located on the refraction path; and the other aperture is arranged at the combined focal length focus of the common module front group (100) located on the reflection path.

10. The modular high-magnification telecentric lens assembly according to claim 2, characterized in that: A semi-transparent and semi-reflective prism is also arranged between the seventh lens (170) and the aperture T; A rear group is arranged on the refraction path of the semi-transparent and semi-reflective prism; a coaxial illumination light source is arranged on the reflection path of the semi-transparent and semi-reflective prism; The aperture T is arranged at the combined focal length focus of the common module front group (100) located on the refraction path.

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