Double-view measuring lens and optical system thereof

Abstract

The invention relates to the technical field of machine vision lenses, and discloses a double-view measuring lens and an optical system thereof. The optical system comprises a front group, a beam splitter prism and a rear group which are sequentially arranged from an object side to an image side, the rear group comprises a first multiplying power rear group arranged on a refraction path of the beam splitter prism and a second multiplying power rear group arranged on a reflection path of the beam splitter prism; a first diaphragm is arranged between the first multiplying power rear group and the beam splitter prism, and the first diaphragm is arranged at the combined focal length, located on the refraction path, of the front group; and a second diaphragm is arranged between the second multiplying power rear group and the beam splitter prism, and the second diaphragm is arranged at the combined focal length of the front group on the reflection path. The optical system provided by the invention is compact in structure and has two rear groups with different multiplying power, so that the optical system can be connected with two cameras for simultaneous detection, simultaneous measurement of a large field of view and a small field of view is realized, the precision is improved, the measurement time can be shortened, and the test efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of machine vision lenses, and in particular to a dual-field-of-view measurement lens and an optical system thereof. Background Art

[0002] With the rapid development of the machine vision industry, imagers based on visual inspection can achieve accurate measurement and analysis of product size, shape and surface features, and have been rapidly popularized in the field of industrial manufacturing, such as 3C electronics factories and precision hardware processing factories. At present, many imager measurement lenses on the market have only a single field of view and a single magnification, which cannot achieve dual-camera simultaneous measurement, and the measurement efficiency is low; the existing dual-field imager measurement lenses have the problem of long structural length, resulting in a bloated optical structure.

[0003] Therefore, for those skilled in the art, how to improve accuracy while shortening the measurement time and improving test efficiency has become a technical problem that needs to be solved urgently in this field.

[0004] The above information is presented as background information only to assist with understanding the present disclosure and no determination or admission is made as to whether any of the above may be used as prior art with respect to the present disclosure. Summary of the invention

[0005] The object of the present invention is to provide a dual-field-of-view measurement lens and an optical system thereof, so as to solve or at least partially solve the technical problems existing in the prior art.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides an optical system of a dual-field-of-view measurement lens, comprising a front group, a beam splitter prism and a rear group with positive optical power, which are arranged in sequence from the object side to the image side;

[0008] The front group includes a first lens with positive power, a second lens with positive power, a third lens with positive power, and a fourth lens with negative power; wherein the third lens and the fourth lens form a first cemented lens with negative power;

[0009] The rear group includes a first magnification rear group with positive optical power disposed on the refractive path of the beam splitter prism and a second magnification rear group with positive optical power disposed on the reflective path of the beam splitter prism;

[0010] A first aperture is arranged between the first magnification rear group and the dichroic prism, and the first aperture is arranged at the combined focal length of the front group on the refraction path; a second aperture is arranged between the second magnification rear group and the dichroic prism, and the second aperture is arranged at the combined focal length of the front group on the reflection path.

[0011] Optionally, the combined focal length of the front group is f 100 , the focal length of the first lens is f 110 , the focal length of the second lens 120 is f 120 , the focal length of the first cemented lens is f U1 ;

[0012] f 110 and f 100 satisfy the relation: 1.5 < |f 110 / f 100 | < 2.5;

[0013] f 110 and f 120 satisfy the relation: 0.75 < |f 110 / f 120 | < 1.25;

[0014] f U1 and f 100 satisfy the relation: 0.5 < |f U1 / f 100 | < 0.75.

[0015] Optionally, the first magnification rear group includes a fifth lens with a negative optical power, a sixth lens with a positive optical power, a seventh lens with a positive optical power, and an eighth lens with a positive optical power, which are arranged in sequence from the first diaphragm to the first image plane; among them, the fifth lens and the sixth lens form a second cemented lens with a negative optical power;

[0016] The combined focal length of the first magnification rear group is f 200 , the focal length of the second cemented lens is f U2 , the focal length of the seventh lens is f 230 , the focal length of the eighth lens is f 240 ;

[0017] f 230 and f 200 satisfy the relation: 1.4 < |f 230 / f 200 | < 3;

[0018] f 240 and f 200 satisfy the relation: 1.2 < |f 240 / f 200 | < 2;

[0019] f U2 and f 200 satisfy the relation: 1.5 < |f U2 / f 200 | < 2.5.

[0020] Optionally, the second magnification rear group includes a ninth lens with a negative focal power, a tenth lens with a positive focal power, an eleventh lens with a positive focal power, and a twelfth lens with a positive focal power, which are sequentially arranged from the second aperture stop to the second image plane; among them, the ninth lens and the tenth lens form a third cemented lens with a negative focal power;

[0021] The combined focal length of the second magnification rear group is f 300 , the focal length of the third cemented lens is f U3 , the focal length of the eleventh lens is f 330 , the focal length of the twelfth lens is f 340 ;

[0022] f U3 and f 300 satisfy the relational expression: 1.6 < |f U3 / f 300 | < 2.6;

[0023] f 330 and f 300 satisfy the relational expression: 2 < |f 330 / f 300 | < 3;

[0024] f 340 and f 300 satisfy the relational expression: 1.8 < |f 340 / f 300 | < 2.8.

[0025] Optionally, in the front group, the first lens is a plano-convex lens or a meniscus lens, and the second, third, and fourth lenses are all meniscus lenses;

[0026] In the first magnification rear group, the fifth lens is a biconcave lens, and the sixth, seventh, and eighth lenses are all biconvex lenses;

[0027] In the second magnification rear group, the ninth lens is a biconcave lens, and the tenth, eleventh, and twelfth lenses are all biconvex lenses.

[0028] Optionally, the beam splitting prism is a semi-transmissive and semi-reflective prism.

[0029] Optionally, the materials of the second lens and the third lens are crown glass.

[0030] Optionally, the optical axes of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens are all on a predetermined first optical axis; the optical axes of the ninth lens, the tenth lens, the eleventh lens, and the twelfth lens are all on a predetermined second optical axis; the first optical axis and the second optical axis are perpendicular;

[0031] The aperture center of the first diaphragm is on the first optical axis, and the aperture center of the second diaphragm is on the second optical axis.

[0032] Optionally, the magnification of the first magnification rear group is less than that of the second magnification rear group.

[0033] In a second aspect, the present invention provides a dual-field-of-view measurement lens, including the optical system of a dual-field-of-view measurement lens as described above.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] This application realizes a dual-field-of-view measurement lens with a compact structure, which can effectively compress the length dimension; it has two rear groups with different magnifications, so two cameras can be connected for detection at the same time, realizing simultaneous measurement of a large field of view and a small field of view. While improving the accuracy, it can also shorten the measurement time and improve the test efficiency.

[0036] The present invention has other characteristics and advantages, which will be obvious from the accompanying drawings incorporated herein and the subsequent specific embodiments, or will be described in detail in the accompanying drawings incorporated herein and the subsequent specific embodiments. These drawings and specific embodiments are jointly used to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] 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, without creative efforts, other drawings can be obtained based on these drawings.

[0038] Figure 1 It is a schematic structural diagram of an optical system of a dual-field-of-view measurement lens provided by an embodiment of the present invention.

[0039] Figure 2 It is an optical path diagram of an optical system of a dual-field-of-view measurement lens provided by an embodiment of the present invention.

[0040] Figure 3 It is a schematic front group structure diagram provided by an embodiment of the present invention.

[0041] Figure 4 It is a schematic structural diagram of the first magnification rear group provided by an embodiment of the present invention.

[0042] Figure 5 It is a schematic structural diagram of the second magnification rear group provided by an embodiment of the present invention.

[0043] Figure 6MTF diagram of the low-magnification optical system provided by the embodiment of the present invention.

[0044] Figure 7 MTF diagram of the high-magnification optical system provided by the embodiment of the present invention.

[0045] Figure 8 Schematic diagram of the distortion of the low-magnification optical system provided by the embodiment of the present invention.

[0046] Figure 9 Schematic diagram of the distortion of the high-magnification optical system provided by the embodiment of the present invention. Detailed implementation manners

[0047] To describe in detail the possible application scenarios, technical principles, specific implementable solutions, achievable objectives and effects, etc. of the present application, the following will be described in detail in conjunction with the listed specific embodiments and with reference to 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.

[0048] Referring to "embodiment" herein means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The term "embodiment" appearing in 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 the corresponding implementable technical solution.

[0049] Unless otherwise defined, the meanings of the technical terms used herein 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 herein is only for describing specific embodiments and is not intended to limit the present application.

[0050] In the description of the present application, the phrase "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, which means: there is A, there is B, and there is both A and B at the same time. In addition, the character " / " herein generally represents an "or" logical relationship between the associated objects before and after.

[0051] In the present 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 quantity, primary or secondary, or order relationship between these entities or operations.

[0052] Without further limitations, in this application, the terms "comprising", "including", "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 process, method or product.

[0053] Similar to the understanding in the "Examination Guidelines", in this application, expressions such as "greater than", "less than", "exceeding" are understood as not including the number itself; expressions such as "above", "below", "within" are understood as including the number itself. In addition, in the description of the embodiments of this application, the meaning of "a plurality of" is two or more (including two), and similar expressions related to "many" are understood in the same way, such as "multiple groups", "multiple times", etc., unless otherwise specifically defined.

[0054] 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., the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the specific embodiment or the drawings. It is only for the convenience of describing the specific embodiments of this application or for the reader's understanding, rather than indicating or implying 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 to the embodiments of this application.

[0055] 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 technical field to which this application belongs, the specific meanings of the above terms in the embodiments of this application can be understood according to specific circumstances.

[0056] Embodiment 1:

[0057] Please refer to Figure 1 and Figure 2 , Figure 1 is a schematic structural diagram of an optical system of a dual-field-of-view measurement lens provided by an embodiment of the present invention. Figure 2Optical path diagram of an optical system of a dual-field-of-view measurement lens provided by an embodiment of the present invention.

[0058] As Figure 1 shown, the optical system includes:

[0059] Including a front group 100 with positive optical power, a beam splitter prism BS, and a rear group arranged in sequence from the object side to the image side;

[0060] The 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, and a fourth lens 140 with negative optical power; wherein, the third lens 130 and the fourth lens 140 form a first cemented lens U1 with negative optical power;

[0061] The rear group includes a first magnification rear group 200 with positive optical power arranged on the refraction path of the beam splitter prism BS and a second magnification rear group 300 with positive optical power arranged on the reflection path of the beam splitter prism BS;

[0062] A first aperture stop S1 is arranged between the first magnification rear group 200 and the beam splitter prism BS, and the first aperture stop S1 is arranged at the combined focal length of the front group 100 on the refraction path; a second aperture stop S2 is arranged between the second magnification rear group 300 and the beam splitter prism BS, and the second aperture stop S2 is arranged at the combined focal length of the front group 100 on the reflection path.

[0063] Please refer to Figures 3 - 5 , Figure 3 structural schematic diagram of the front group 100 provided by an embodiment of the present invention, Figure 4 structural schematic diagram of the first magnification rear group 200 provided by an embodiment of the present invention, Figure 5 structural schematic diagram of the second magnification rear group 300 provided by an embodiment of the present invention;

[0064] As Figure 4 and Figure 5 shown, the first magnification rear group 200 is placed along the transmitted light direction of the beam splitter prism BS, and the second magnification rear group 300 is placed along the reflected light direction of the beam splitter prism BS; both the first aperture stop S1 and the second aperture stop S2 are located at the combined focal length of the front group 100, forming a telecentric structure to reduce measurement errors.

[0065] Furthermore, the combined focal length of the front group 100 is f 100 , 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 first cemented lens U1 is f U1 ;

[0066] f 110 and f 100Satisfy the relationship: 1.5 < |f 110 / f 100 | < 2.5;

[0067] f 110 and f 120 Satisfy the relationship: 0.75 < |f 110 / f 120 | < 1.25;

[0068] f U1 and f 100 Satisfy the relationship: 0.5 < |f U1 / f 100 | < 0.75.

[0069] As Figure 3 shown, in this embodiment, the first lens 110 and the second lens 120 have similar focal lengths, can better share the ability to deflect light, is conducive to compressing the system length, and at the same time the light incident angle is not too large, reducing off-axis aberrations.

[0070] Further, the first magnification rear group 200 includes a fifth lens 210 with a negative optical power, a sixth lens 220 with a positive optical power, a seventh lens 230 with a positive optical power, and an eighth lens 240 with a positive optical power, which are sequentially arranged from the first aperture S1 to the first image plane; wherein, the fifth lens 210 and the sixth lens 220 form a second cemented lens U2 with a negative optical power;

[0071] The combined focal length of the first magnification rear group 200 is f 200 , the focal length of the second cemented lens U2 is f U2 , the focal length of the seventh lens 230 is f 230 , the focal length of the eighth lens 240 is f 240 ;

[0072] f 230 and f 200 Satisfy the relationship: 1.4 < |f 230 / f 200 | < 3;

[0073] f 240 and f 200 Satisfy the relationship: 1.2 < |f 240 / f 200 | < 2;

[0074] f U2 and f 200 Satisfy the relationship: 1.5 < |f U2 / f 200 | < 2.5.

[0075] The front group 100 causes an increase in the angle of light entering the first magnification rear group 200 due to length compression. The sixth lens 220, the seventh lens 230, and the eighth lens 240 all have positive optical power and a biconvex structure, which is beneficial to reducing aberrations caused by light with a large incident angle. In this embodiment, the seventh lens 230 and the eighth lens 240 are made of glass materials with a high refractive index, which is beneficial to alleviating the incident angle of light entering the lens and reducing the tolerance sensitivity.

[0076] Specifically, the second magnification rear group 300 includes a ninth lens 310 with negative optical power, a tenth lens 320 with positive optical power, an eleventh lens 330 with positive optical power, and a twelfth lens 340 with positive optical power, which are sequentially arranged from the second aperture stop S2 to the second image plane; among them, the ninth lens 310 and the tenth lens 320 form a third cemented lens U3 with negative optical power;

[0077] The combined focal length of the second magnification rear group 300 is f 300 , the focal length of the third cemented lens U3 is f U3 , the focal length of the eleventh lens 330 is f 330 , the focal length of the twelfth lens 340 is f 340 ;

[0078] f U3 and f 300 satisfy the relationship: 1.6 < |f U3 / f 300 | < 2.6;

[0079] f 330 and f 300 satisfy the relationship: 2 < |f 330 / f 300 | < 3;

[0080] f 340 and f 300 satisfy the relationship: 1.8 < |f 340 / f 300 | < 2.8.

[0081] More specifically, in this embodiment, in the front group 100, the first lens 110 is a plano-convex lens or a meniscus lens, and the second lens 120, the third lens 130, and the fourth lens 140 are all meniscus lenses;

[0082] In the first magnification rear group 200, the fifth lens 210 is a biconcave lens, and the sixth lens 220, the seventh lens 230, and the eighth lens 240 are all biconvex lenses;

[0083] In the second magnification rear group 300, the ninth lens 310 is a biconcave lens, and the tenth lens 320, the eleventh lens 330, and the twelfth lens 340 are all biconvex lenses.

[0084] The beam-splitting prism BS is a semi-transmissive and semi-reflective prism.

[0085] As a preferred embodiment, the materials of the second lens 120 and the third lens 130 are crown glass. Using a crown glass lens combination is more conducive to correcting the chromatic aberration of the system.

[0086] Such as Figure 1 or Figure 2 As shown, the optical axes of the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the fifth lens 210, the sixth lens 220, the seventh lens 230, and the eighth lens 240 are all on a predetermined first optical axis ( Figure 1 the horizontal dotted line in Figure 1 ); the optical axes of the ninth lens 310, the tenth lens 320, the eleventh lens 330, and the twelfth lens 340 are all on a predetermined second optical axis (

[0087] the vertical dotted line in

[0088] It should be noted that the magnification of the first magnification rear group 200 is less than that of the second magnification rear group 300; in this embodiment, the first magnification rear group 200 is a low-magnification rear group, and the second magnification rear group 300 is a high-magnification rear group.

[0089] It can be understood that the aperture value of the diaphragm needs to be adjusted correspondingly according to the specific application scenario.

[0090] To verify whether the above optical system meets the design purpose, the following is a specific test example given according to the above settings of this embodiment:

[0091] In this test example, the data of each lens of the measurement lens optical system composed of the front group 100 and the first magnification rear group 200 are shown in Table 1 below:

[0092] Table 1

[0093]

[0094]

[0095] It should be noted that in Table 1, "front surface" corresponds to Figure 1 the left surface of the corresponding lens or lens group in Figure 1 and "rear surface" corresponds to

[0096] The lens data of each lens of the measurement lens optical system composed of the front group 100 and the second magnification rear group 300 are shown in Table 2 below:

[0097] Table 2

[0098]

[0099]

[0100] It should be noted that in Table 2, the "front surface" of each lens in the second magnification rear group 300 corresponds to Figure 1 the lower surface of the corresponding lens or lens group in Figure 5 (or the left surface of the corresponding lens or lens group in Figure 1 ), and the "rear surface" corresponds to Figure 5 the upper surface of the corresponding lens or lens group in

[0101] In this test example, the combined focal length f 100 of the front group 100 is 119 mm; the focal length f 110 of the first lens 110 is 234 mm, the focal length f 120 of the second lens 120 is 221 mm, and the focal length f U1 of the first cemented lens U1 is -89 mm; the combined focal length f 200 of the first magnification rear group 200 is 19 mm, the focal length f 230 of the seventh lens 230 is 32 mm, the focal length f 240 of the eighth lens 240 is 40 mm, and the focal length f U2 of the second cemented lens U2 is -42 mm;

[0102] The combined focal length f 300 of the second magnification rear group 200 is 51 mm, the focal length f 330 of the eleventh lens 330 is 67 mm, the focal length f 340 of the twelfth lens 340 is 110 mm, and the focal length f U3 of the third cemented lens U3 is -128 mm;

[0103] Substituting the above values into each relational expression shows that they all satisfy the relevant relational expressions of this embodiment, that is:

[0104] 1.5 < |f 110 / f 100 | < 2.5, 0.75 < |f 110 / f 120 | < 1.25, 0.5 < |f U1 / f 100 | < 0.75;

[0105] 1.4 <|f 230 / f 200 |<3, 1.2 <|f 240 / f 200 |<2, 1.5 <|f U2 / f 200 |<2.5;

[0106] 1.6 <|f U3 / f 300 |<2.6, 2 <|f 330 / f 300 |<3, 1.8 <|f 340 / f 300 |<2.8。

[0107] Please refer to Figures 6 - 9 , Figure 6 , which is the MTF (Modulation Transfer Function) graph of the small magnification optical system provided by the embodiment of the present invention, Figure 7 , and is the MTF graph of the large magnification optical system of the embodiment of the present invention, Figure 8 , and is the distortion schematic diagram of the small magnification optical system of the embodiment of the present invention, Figure 9 , and is the distortion schematic diagram of the large magnification optical system of the embodiment of the present invention.

[0108] In this example, the front group 100 and the first magnification rear group 200 form a small magnification measurement lens optical system, and its optical parameters are shown in Table 3 below:

[0109] Table 3

[0110] Working distance WD 150 mm Magnification ratio 0.16 times Field of view φ100 mm Target surface 1 inch MTF30 > 140 lp / mm Telecentricity <0.02° Distortion <0.05％

[0111] In this example, the front group 100 and the second magnification rear group 300 form a large magnification measurement lens optical system, and its optical parameters are shown in Table 4 below:

[0112] Table 4

[0113] Working distance WD 150 mm Magnification ratio 0.44 times Field of view Φ40 mm Target surface 1.1 inches MTF30 > 140 lp / mm Telecentricity <0.02° Distortion <0.03％

[0114] In summary, through the above structure, this embodiment realizes an optical system of a dual-field-of-view measurement lens, which is structurally compact and can effectively compress the length dimension; it has two magnifications, 0.16 times and 0.44 times respectively, and can be connected to two cameras for simultaneous detection, realizing simultaneous measurement of a large field of view and a small field of view. While improving the accuracy, it can also shorten the measurement time and improve the test efficiency.

[0115] Embodiment 2:

[0116] This embodiment provides a dual-field measurement lens, including the optical system of a dual-field measurement lens as described in Embodiment 1.

[0117] Based on the relatively detailed description of the optical system in the above embodiment, it will not be elaborated in this embodiment.

[0118] In summary, this embodiment realizes a dual-field measurement lens through the above structure. The structure is compact and can effectively compress the length dimension. It has two magnifications, 0.16 times and 0.44 times respectively, and can be connected to two cameras for simultaneous detection to achieve simultaneous measurement of large and small fields of view. The appearance size or overall shape of the target object can be magnified and quickly captured by the large-field camera, and the position requiring fine shape and accuracy is switched to the small-field camera for measurement. Thus, while improving the accuracy, the measurement time can be shortened.

[0119] As mentioned above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; 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 for 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 various embodiments of the present invention.

Claims

1. An optical system of a dual-field measurement lens, characterized in that: It comprises a front group (100) with positive optical power, a beam splitter prism and a rear group which are arranged in sequence from the object side to the image side; The front group (100) includes a first lens (110) having positive power, a second lens (120) having positive power, a third lens (130) having positive power, and a fourth lens (140) having negative power; wherein the third lens (130) and the fourth lens (140) form a first cemented lens having negative power; The rear group comprises a first magnification rear group (200) with positive optical power arranged on the refractive path of the dichroic prism and a second magnification rear group (300) with positive optical power arranged on the reflective path of the dichroic prism; A first aperture is arranged between the first magnification rear group (200) and the dichroic prism, and the first aperture is arranged at the combined focal length of the front group (100) located on the refraction path; a second aperture is arranged between the second magnification rear group (300) and the dichroic prism, and the second aperture is arranged at the combined focal length of the front group (100) located on the reflection path.

2. The optical system of a dual-field measurement lens according to claim 1, characterized in that: The combined focal length of the front group (100) is f 100 , 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 first cemented lens is f U1 ; f 110 and f 100 Satisfies the relationship: 1.5<|f 110 / f 100 |<2.5; f 110 and f 120 Satisfies the relationship: 0.75<|f 110 / f 120 |<1.25; f U1 and f 100 Satisfies the relationship: 0.5<|f U1 / f 100 |<0.

75.

3. The optical system of a dual-field measurement lens according to claim 2, characterized in that: The first magnification rear group (200) includes a fifth lens (210) with negative focal power, a sixth lens (220) with positive focal power, a seventh lens (230) with positive focal power, and an eighth lens (240) with positive focal power, which are arranged in sequence from the first aperture to the first image plane; wherein the fifth lens (210) and the sixth lens (220) form a second cemented lens with negative focal power; The combined focal length of the first magnification rear group (200) is f 200 , the focal length of the second doublet is f U2 , the focal length of the seventh lens (230) is f 230 , the focal length of the eighth lens (240) is f 240 ; f 230 and f 200 Satisfies the relationship: 1.4<|f 230 / f 200 |<3; f 240 and f 200 Satisfies the relationship: 1.2<|f 240 / f 200 |<2; f U2 and f 200 Satisfies the relationship: 1.5<|f U2 / f 200 |<2.

5.

4. The optical system of a dual-field measurement lens according to claim 3, characterized in that: The second magnification rear group (300) includes a ninth lens (310) with negative focal power, a tenth lens (320) with positive focal power, an eleventh lens (330) with positive focal power, and a twelfth lens (340) with positive focal power, which are arranged in sequence from the second aperture to the second image plane; wherein the ninth lens (310) and the tenth lens (320) form a third cemented lens with negative focal power; The combined focal length of the second magnification rear group (300) is f 300 , the focal length of the third doublet is f U3 , the focal length of the eleventh lens (330) is f 330 , the focal length of the twelfth lens (340) is f 340 ; f U3 and f 300 Satisfies the relationship: 1.6<|f U3 / f 300 |<2.6; f 330 and f 300 Satisfies the relationship: 2<|f 330 / f 300 |<3; f 340 and f 300 Satisfies the relationship: 1.8<|f 340 / f 300 |<2.

8.

5. The optical system of a dual-field-of-view measurement lens according to claim 4, characterized in that: In the front group (100), the first lens (110) is a plano-convex lens or a meniscus lens, and the second lens (120), the third lens (130) and the fourth lens (140) are all meniscus lenses; In the first magnification rear group (200), the fifth lens (210) is a biconcave lens, and the sixth lens (220), the seventh lens (230) and the eighth lens (240) are all biconvex lenses; In the second magnification rear group (300), the ninth lens (310) is a biconcave lens, and the tenth lens (320), the eleventh lens (330) and the twelfth lens (340) are all biconvex lenses.

6. The optical system of a dual-field-of-view measurement lens according to claim 4, characterized in that: The dichroic prism is a semi-transparent and semi-reflective prism.

7. The optical system of a dual-field-of-view measurement lens according to claim 4, characterized in that: The second lens (120) and the third lens (130) are made of crown glass.

8. The optical system of a dual-field-of-view measurement lens according to claim 1, characterized in that: The optical axes of the first lens (110), the second lens (120), the third lens (130), the fourth lens (140), the fifth lens (210), the sixth lens (220), the seventh lens (230) and the eighth lens (240) are all on a predetermined first optical axis; The optical axes of the ninth lens (310), the tenth lens (320), the eleventh lens (330) and the twelfth lens (340) are all on a predetermined second optical axis; the first optical axis and the second optical axis are perpendicular; The aperture center of the first aperture is on the first optical axis, and the aperture center of the second aperture is on the second optical axis.

9. The optical system of a dual-field measurement lens according to claim 1, characterized in that: The magnification of the first magnification rear group (200) is smaller than the magnification of the second magnification rear group (300).

10. A dual-field-of-view measurement lens, characterized in that: An optical system comprising a dual-field measurement lens as claimed in any one of claims 1 to 9.

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